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We report on the first measurement of inclusive J/ψ elliptic flow, v2, in heavy-ion collisions at the LHC. The measurement is performed with the ALICE detector in Pb-Pb collisions at sNN−−−√=2.76 TeV in the rapidity range 2.5<y<4.0. The dependence of the J/ψ v2 on the collision centrality and on the J/ψ transverse momentum is studied in the range 0<pT<10 GeV/c. For semi-central Pb-Pb collisions at sNN−−−√=2.76 TeV, an indication of non-zero v2 is observed with a maximum value of v2=0.116±0.046(stat.)±0.029(syst.) for J/ψ in the transverse momentum range 2<pT<4 GeV/c. The elliptic flow measurement complements the previously reported ALICE results on the inclusive J/ψ nuclear modification factor and favors the scenario of a significant fraction of J/ψ production from charm quarks in a deconfined partonic phase.
Measurements of cross sections of inelastic and diffractive processes in proton--proton collisions at LHC energies were carried out with the ALICE detector. The fractions of diffractive processes in inelastic collisions were determined from a study of gaps in charged particle pseudorapidity distributions: for single diffraction (diffractive mass MX<200 GeV/c2) σSD/σINEL=0.21±0.03,0.20+0.07−0.08, and 0.20+0.04−0.07, respectively at centre-of-mass energies s√=0.9,2.76, and 7~TeV; for double diffraction (for a pseudorapidity gap Δη>3) σDD/σINEL=0.11±0.03,0.12±0.05, and 0.12+0.05−0.04, respectively at s√=0.9,2.76, and 7~TeV. To measure the inelastic cross section, beam properties were determined with van der Meer scans, and, using a simulation of diffraction adjusted to data, the following values were obtained: σINEL=62.8+2.4−4.0(model)±1.2(lumi) mb at s√= 2.76~TeV and 73.2+2.0−4.6(model)±2.6(lumi) mb at s√ = 7~TeV. The single- and double-diffractive cross sections were calculated combining relative rates of diffraction with inelastic cross sections. The results are compared to previous measurements at proton--antiproton and proton--proton colliders at lower energies, to measurements by other experiments at the LHC, and to theoretical models.
In high-energy heavy-ion collisions, the correlations between the emitted particles can be used as a probe to gain insight into the charge creation mechanisms. In this article, we report the first results of such studies using the electric charge balance function in the relative pseudorapidity \Delta\eta and azimuthal angle \Delta\phi in Pb-Pb collisions at sqrt{s_{NN}} = 2.76 TeV with the ALICE detector at the Large Hadron Collider. The width of the balance function decreases with growing centrality (i.e. for more central collisions) in both projections. This centrality dependence is not reproduced by HIJING, while AMPT, a model which incorporates strings and parton rescattering, exhibits qualitative agreement with the measured correlations in \Delta\phi but fails to describe the correlations in \Delta\eta. A thermal blast wave model incorporating local charge conservation and tuned to describe the p_T spectra and v_2 measurements reported by ALICE, is used to fit the centrality dependence of the width of the balance function and to extract the average separation of balancing charges at freeze-out. The comparison of our results with measurements at lower energies reveals an ordering with sqrt{s_{NN}}: the balance functions become narrower with increasing energy for all centralities. This is consistent with the effect of larger radial flow at the LHC energies but also with the late stage creation scenario of balancing charges. However, the relative decrease of the balance function widths in \Delta\eta and \Delta\phi with centrality from the highest SPS to the LHC energy exhibits only small differences. This observation cannot be interpreted solely within the framework where the majority of the charge is produced at a later stage in the evolution of the heavy-ion collision.
In high--energy heavy--ion collisions, the correlations between the emitted particles can be used as a probe to gain insight into the charge creation mechanisms. In this Letter, we report the first results of such studies using the electric charge balance function in the relative pseudorapidity (Δη) and azimuthal angle (Δφ) in Pb--Pb collisions at sNN−−−−√=2.76 TeV with the ALICE detector at the Large Hadron Collider. The width of the balance function decreases with growing centrality (i.e. for more central collisions) in both projections. This centrality dependence is not reproduced by HIJING, while AMPT, a model which incorporates strings and parton rescattering, exhibits qualitative agreement with the measured correlations in Δφ but fails to describe the correlations in Δη. A thermal blast--wave model incorporating local charge conservation and tuned to describe the pmT spectra and v2 measurements reported by ALICE, is used to fit the centrality dependence of the width of the balance function and to extract the average separation of balancing charges at freeze--out. The comparison of our results with measurements at lower energies reveals an ordering with sNN−−−−√:the balance functions become narrower with increasing energy for all centralities. This is consistent with the effect of larger radial flow at the LHC energies but also with the late stage creation scenario of balancing charges. However, the relative decrease of the balance function widths in Δη and \dphi with centrality from the highest SPS to the LHC energy exhibits only small differences. This observation cannot be interpreted solely within the framework where the majority of the charge is produced at a later stage in the evolution of the heavy--ion collision.
n this paper measurements are presented of π+, π−, K+, K−, p and p¯¯¯ production at mid-rapidity < 0.5, in Pb-Pb collisions at sNN−−−√=2.76 TeV as a function of centrality. The measurement covers the transverse momentum (pT) range from 100, 200, 300 MeV/c up to 3, 3, 4.6 GeV/c, for π, K, and p respectively. The measured pT distributions and yields are compared to expectations based on hydrodynamic, thermal and recombination models. The spectral shapes of central collisions show a stronger radial flow than measured at lower energies, which can be described in hydrodynamic models. In peripheral collisions, the pT distributions are not well reproduced by hydrodynamic models. Ratios of integrated particle yields are found to be nearly independent of centrality. The yield of protons normalized to pions is a factor ~1.5 lower than the expectation from thermal models.
We present the first wide-range measurement of the charged-particle pseudorapidity density distribution, for different centralities (the 0-5%, 5-10%, 10-20%, and 20-30% most central events) in Pb-Pb collisions at sNN−−−√=2.76 TeV at the LHC. The measurement is performed using the full coverage of the ALICE detectors, −5.0<η<5.5, and employing a special analysis technique based on collisions arising from LHC "satellite" bunches. We present the pseudorapidity density as a function of the number of participating nucleons as well as an extrapolation to the total number of produced charged particles (Nch=17165±772 for the 0-5% most central collisions). From the measured dNch/dη distribution we derive the rapidity density distribution, dNch/dy, under simple assumptions. The rapidity density distribution is found to be significantly wider than the predictions of the Landau model. We assess the validity of longitudinal scaling by comparing to lower energy results from RHIC. Finally the mechanisms of the underlying particle production are discussed based on a comparison with various theoretical models.
Measurements of charge-dependent azimuthal correlations with the ALICE detector at the LHC are reported for Pb-Pb collisions at √𝑠𝑁𝑁=2.76 TeV. Two- and three-particle charge-dependent azimuthal correlations in the pseudorapidity range |𝜂|<0.8 are presented as a function of the collision centrality, particle separation in pseudorapidity, and transverse momentum. A clear signal compatible with a charge-dependent separation relative to the reaction plane is observed, which shows little or no collision energy dependence when compared to measurements at RHIC energies. This provides a new insight for understanding the nature of the charge-dependent azimuthal correlations observed at RHIC and LHC energies.
We report the first measurement of the net-charge fluctuations in Pb-Pb collisions at sNN−−−√ = 2.76 TeV, measured with the ALICE detector at the CERN Large Hadron Collider. The dynamical fluctuations per unit entropy are observed to decrease when going from peripheral to central collisions. An additional reduction in the amount of fluctuations is seen in comparison to the results from lower energies. We examine the dependence of fluctuations on the pseudorapidity interval, which may account for the dilution of fluctuations during the evolution of the system. We find that the fluctuations at LHC are smaller compared to the measurements at the Relativistic heavy Ion Collider (RHIC), and as such, closer to what has been theoretically predicted for the formation of Quark-Gluon Plasma (QGP).
This publication describes the methods used to measure the centrality of inelastic Pb-Pb collisions at a center-of-mass energy of 2.76 TeV per colliding nucleon pair with ALICE. The centrality is a key parameter in the study of the properties of QCD matter at extreme temperature and energy density, because it is directly related to the initial overlap region of the colliding nuclei. Geometrical properties of the collision, such as the number of participating nucleons and number of binary nucleon-nucleon collisions, are deduced from a Glauber model with a sharp impact parameter selection, and shown to be consistent with those extracted from the data. The centrality determination provides a tool to compare ALICE measurements with those of other experiments and with theoretical calculations.
Correlations of two charged identical kaons (KchKch) are measured in pp collisions at s√=7~TeV by the ALICE experiment at the Large Hadron Collider (LHC). One-dimensional KchKch correlation functions are constructed in three multiplicity and four transverse momentum ranges. The KchKch femtoscopic source parameters R and λ are extracted. The KchKch correlations show a slight increase of femtoscopic radii with increasing multiplicity and a slight decrease of radii with increasing transverse momentum. These trends are similar to the ones observed for ππ and K0sK0s correlations in pp and heavy-ion collisions. However at high multiplicities, there is an indication that the one-dimensional correlation radii for charged kaons are larger than those for pions in contrast to what was observed in heavy-ion collisions at RHIC.
We present the analysis of the semi-inclusive distribution of reconstructed charged particle jets recoiling from a high pT hadron trigger in central Pb Pb collisions at sNN−−−−√=2.76 TeV. We measure, subtract and unfold the large underlying event background in such collisions, utilizing a novel technique that does not impose fragmentation bias on the measured jet population. The Pb Pb measurements are compared to a pp PYTHIA reference distribution generated at the same s√. Modification of jet structure due to quenching is explored by varying the cone radius R (0.2, 0.4) and the lower pT cutoff of charged particle constituents (0.15, 2.0 GeV/c).
The charged-particle pseudorapidity density measured over 4 units of pseudorapidity in non-single-diffractive (NSD) p-Pb collisions at a centre-of-mass energy per nucleon pair sNN−−−√=5.02 TeV is presented. The average value at midrapidity is measured to be 16.81±0.71 (syst.), which corresponds to 2.14±0.17 (syst.) per participating nucleon. This is 16% lower than in NSD pp collisions interpolated to the same collision energy, and 84% higher than in d-Au collisions at sNN−−−√=0.2 TeV. The measured pseudorapidity density in p-Pb collisions is compared to model predictions, and provides new constraints on the description of particle production in high-energy nuclear collisions.
Measurement of the inclusive differential jet cross section in pp collisions at √s = 2.76 TeV
(2013)
The ALICE collaboration at the CERN Large Hadron Collider reports the first measurement of the inclusive differential jet cross section at mid-rapidity in pp collisions at s√=2.76 TeV, with integrated luminosity of 13.6 nb−1. Jets are measured over the transverse momentum range 20 to 125 GeV/c and are corrected to the particle level. Calculations based on Next-to-Leading Order perturbative QCD are in good agreement with the measurements. The ratio of inclusive jet cross sections for jet radii R=0.2 and R=0.4 is reported, and is also well reproduced by a Next-to-Leading Order perturbative QCD calculation when hadronization effects are included.
In Dutch V-final clauses the verbs tend to form a cluster in which the main verb is separated from its syntactic arguments by one or more other verbs. In HPSG the link between the main verb and its arguments is canonically modeled in terms of argument inheritance, also known as argument composition or generalized raising. When applied to Dutch, this treatment yields a number of problems, making incorrect predictions about the interaction with the binding principles and the passive lexical rule. To repair them this paper proposes an alternative, in which subject raising and complement raising are modeled in terms of different devices. More specifically, while subject raising is modeled in terms of lexical constraints, as for English, complement raising is modeled in terms of a more general constraint on headed phrases. This new constraint not only accounts for complement raising out of verbal complements, it also deals with complement raising out of adjectival and adpositional complements, as well as with complement raising out of PP adjuncts and subject NPs. It is, hence, a rather powerful device. To prevent overgeneration we add a number of constraints. For Dutch, the relevant constraints block complement raising out of CPs, V-initial VPs and P-initial PPs. For English, the Empty COMPS Constraint is sufficient to block complement raising entirely.
Hungarian infinitival constructions have both mono-clausal and bi-clausal properties at the same time. The arguments of the infinitive behave the same way as the arguments of the finite verb do, but the non-finite verb has its own left periphery. After discussing the general description of Hungarian sentence structure and presenting an HPSG analysis for it – including a description of the connection between word order and scope order in the Hungarian left periphery – this paper presents an analysis for Hungarian infinitival constructions. The analysis lexically distinguishes the left peripheral arguments of the infinitive from its complements, and allows the infinitive and its left peripheral arguments to form constituents, while the complements of the infinitive are inherited to the finite verb.
This paper presents a unified approach to multiple nominative and accusative constructions in Korean. We identify 16 semantic relations holding between two consecutive NPs in multiple case marking constructions, and propose each semantic relation as a licensing condition on double case marking. We argue that the multiple case marking constructions are merely the sequences of double case marking, which are formed by dextrosinistrally sequencing the pairs of the same-case marked NPs of same or different type. Some appealing consequences of this proposal include a new comprehensive classification of the sequences of same-case NPs and a straightforward account of some long standing problems such as how the additional same-case NPs are licensed, and in what respects the multiple nominative marking and the multiple accusative marking are alike and different from each other.
This paper presents a syntactic HPSG analysis of distance distributivity in Polish, where the challenge is to uniformly analyse a number of function lexemes PO 'each' which share their form and semantic contribution, but differ in their syntactic behaviour. To this end, the HPSG notion of weak head is employed in a novel way.
We show how the variation in the passive in Danish, English, and German can be accounted for. The dimensions in which the three languages differ are
- the existence of a morphological passive in Danish
- a subject requirement in Danish and English resulting in expletive insertion in impersonal
- constructions in Danish and absence of impersonal passives in English the possibility to promote the secondary object to subject in Danish
The differences are accounted for by differences in the structural/lexical case distinction and by mapping processes that insert expletives in Danish. The passive in general is accounted for by a lexical rule that is uniform across languages and hence captures the generalization regarding passive.
In this paper I introduce the notion of Usage Preferences (UPs), which are statistically significant preferences in usage which can concern any aspect of linguistics. I suggest that multiple violations of UPs can have additive effects, causing grammatical sentences to be judged as unacceptable. A new judgment on sentences is proposed, the downarrow (↓) to mark sentences that are taken to be grammatical but unacceptable due to UP violations. I illustrate the idea of UPs on the basis of a discussion of the English verbal anaphor do so, involving both a corpus analysis and two acceptability experiments. This leads to a discussion of the relationship between grammaticality and acceptability and to remarks on the methodological importance of taking UPs into account both in linguistic theorizing and in the construction of acceptability experiments.
This paper presents an analysis of the complex NP island effects in Chinese. I follow Ginzburg & Sag (2000)'s analysis of in situ wh-interrogative construction and propose that feature percolation from the non-head clause daughter to the head daughter is required for a proper treatment of in situ wh-relative. A semantic analysis of the idiosyncrasy of weishenme 'why' reveals that a definite reading is forced for a wh-relative when weishenme stays in situ. This requirement causes feature percolation into relative head to fail. In this way I show that island effects in Chinese can be independently ruled out in the grammar as a case of contradiction.
The present article discusses several aspects of the so-called correlate-es construction in German. This complex clausal construction can be identified by a correlative nominal element es ('it') occuring in the matrix clause and a right-peripheral full clausal argument linked to es. The article supports the hypothesis that correlative es has a janus-faced nature between an expletive and a referential meaning. This is the reason why existing approaches are not sufficient to capture the properties of the discussed construction in its entirety. The first part of the article sums up the common view on correlative es including the empirical properties of the construction as well as a brief survey of the relevant previous approaches trying to account for correlative es. Based on new empirical data, the second part of the article shows that none of these accounts is able to capture all relevant facts of the correlate-es construction because existing approaches usually ignore that the realization of correlative es is verb-class dependent. Hence, a new constraint-based analysis is developed that takes both empirical observations into account, the verb-class dependence and the janus-faced nature.
Nonverbal predicates in Modern Hebrew have been the subject of investigation in a number of studies. However, to our knowledge, none of them was corpus-based. Corpus searches reveal that the nonverbal constructions which are most commonly addressed in the literature are not the most commonly used ones. Once a broader range of data is considered additional issues are raised. Our analysis addresses these issues, unifying the treatment of three types of copular constructions that we identify in MH. The analysis is implemented as part of a larger-scale grammar, and is extensively tested.
Khoekhoe, a Central Khoisan language, has been claimed to have a clause-second position and topological fields similar to German and Dutch. The position in front of the clause-second position can be occupied by either the matrix verb or a dependent. We argue that monomoraic words are exempt from the general head-final order of Khoekhoe and suggest that this can give rise to discontinuous constituents, where second-position clitics intervene within the VP. We show that this idea provides a simple account of Khoekhoe word order variation and formalize it within a linearization-based HPSG analysis that has a wider scope than the previous Minimalist analyses of Khoekhoe and that is compatible with evidence from tonology.
Simpler Syntax is an approach to grammar that calls for very restrictive limits on the notion of 'grammatical competence'. Specifically, it does not account for unacceptability judgments for sentences that are well-formed if they are fully licensed by the constructions of the language. SS leads us to seek accounts for such judgments in terms other than grammar per se, e.g., processing complexity, semantic or pragmatic well-formedness, discourse coherence, etc. I review several examples that suggest that the line that SS draws between competence on the one hand and performance and other mechanisms on the other is on the right track. Specifically, it does not account for unacceptability judgments for sentences that are well-formed if they are fully licensed by the constructions of the language. SS leads us to seek accounts for such judgments in terms other than grammar per se, e.g., processing complexity, semantic or pragmatic well-formedness, discourse coherence, etc. I review several examples that suggest that the line that SS draws between competence on the one hand and performance and other mechanisms on the other is on the right track.
In most recent work, Crysmann and Bonami (2012) suggest to reconcile the insights of inferential-realisational morphology (Anderson, 1992; Stump, 2001; Brown and Hippisley, 2012) with the full typology of variable morphotactics: situations where the expression of analogous feature sets can appear in various positions in the string. The authors proposed to account for these facts by importing, into HPSG, a variant of Paradigm Function Morphology (Stump, 2001) where realisation rules are doubly indexed for linear position and paradigmatic opposition. In this paper we first introduce more empirical challenges for theories of morphotactics that neither PFM nor the reformist approach of Crysmann and Bonami (2012) can accommodate. We then argue for a reappraisal of methods for morph introduction, and propose a new approach that replaces stipulation of classes of paradigmatic opposition with a general distinction between expression and conditioning (Carstairs, 1987; Noyer, 1992) which greatly expands the scope of Pāṇini’s Principle.
Unbounded dependencies in Modern Standard Arabic often involve not a gap but a null resumptive pronoun. The facts are quite complex, but it is not too difficult to extend the SLASH mechanism of HPSG to handle dependencies with a null resumptive pronoun. It is also not too difficult to restrict the distribution of gaps appropriately.
The transverse momentum (pT) distribution of primary charged particles is measured in minimum bias (non-single-diffractive) p-Pb collisions at sNN−−−√=5.02 TeV with the ALICE detector at the LHC. The pT spectra measured near central rapidity in the range 0.5<pT<20 GeV/c exhibit a weak pseudorapidity dependence. The nuclear modification factor RpPb is consistent with unity for pT above 2 GeV/c. This measurement indicates that the strong suppression of hadron production at high pT observed in Pb-Pb collisions at the LHC is not due to an initial-state effect. The measurement is compared to theoretical calculations.
Highlights
• Floating ability facilitates water dispersal.
• Hydrochorous seed dispersal is more effective than wind dispersal.
• Storage in water induced germination rate.
Abstract
In many Central European countries Fraxinus pennsylvanica is an invasive species that spreads rapidly in floodplain forests. The aim of this study was to analyse anemochorous and hydrochorous dispersal distances and to compare the findings with dispersal data for the native Fraxinus excelsior. A simulation revealed that wind dispersal distances are similar for both species, reaching to 120–250 m. By contrast, the mean floating time (50% floating samaras) measured in an experiment was 2 days in the case of F. pennsylvanica and 0.5 days for F. excelsior. This high floating ability facilitates water dispersal over several kilometres in both species, but for the invasive species the modelled mean dispersal distance was 3.7 times higher. A germination test of F. pennsylvanica seeds revealed that the rate, onset and speed of germination increase with the duration of the inundation. After a maximum storage time in water of about 15 days the germination rate amounts to 78%, which was higher than the germination rate of seeds without storage in water (53%). We also found that regeneration was enhanced in flooded areas. Hydrochory, therefore, may be viewed as an important factor explaining the successful invasion of F. pennsylvanica in floodplain forests in Central Europe.
Seed dispersal is hard to measure, and there is still a lack of knowledge about dispersal-related traits of plant species. Therefore, we developed D3, the Dispersal and Diaspore Database (available at
www.seed-dispersal.info), which aims at simplifying ecological and evolutionary analyses by providing and integrating various items related to seed dispersal: empirical studies, functional traits, image analyses and ranking indices (quantifying the adaptation to dispersal modes).
Currently, the database includes data for more than 5000 taxa and 33 items as well as digital images of diaspores (i.e. the dispersal units), seeds, fruits and infructescences. The included items cover common traits like diaspore mass, size, shape, terminal velocity and seed number per diaspore. Furthermore, we present newly or further developed items like ecomorphological categorizations of the diaspore and fruit as well as information from literature on prevailing dispersal modes. Finally, we introduce several items which are not covered in other databases yet: surface structure and form of the diaspore, the exposure of the diaspores in the infructescence and dispersal rankings. Dispersal rankings allow estimations of how well certain species are adapted to a specific dispersal mode in comparison to a larger species set. They are calculated as the percentile rank of an indicator of species’ dispersal potential in relation to a larger species set.
Especially for the new and further developed items we outline the basic concepts in detail, describe the measurement and categorization methods and show how to interpret and integrate these data for single species as well as for larger species sets. Thereby, we calculate baseline statistics of seed dispersal of the Central European flora. We found that diaspores of 72% of the taxa show specializations related to long-distance dispersal, i.e. most often elongated appendages or nutrient-rich tissues. Diaspore masses, sizes and terminal velocities vary over several orders of magnitude and can be approximated by lognormal distributions.
We report a high precision measurement of the transverse single spin asymmetry AN at the center of mass energy √s=200 GeV in elastic proton–proton scattering by the STAR experiment at RHIC. The AN was measured in the four-momentum transfer squared t range 0.003⩽|t|⩽0.035 (GeV/c)2, the region of a significant interference between the electromagnetic and hadronic scattering amplitudes. The measured values of AN and its t-dependence are consistent with a vanishing hadronic spin-flip amplitude, thus providing strong constraints on the ratio of the single spin-flip to the non-flip amplitudes. Since the hadronic amplitude is dominated by the Pomeron amplitude at this √s, we conclude that this measurement addresses the question about the presence of a hadronic spin flip due to the Pomeron exchange in polarized proton–proton elastic scattering.
The prize-collecting vehicle routing problem with single and multiple depots and non-linear cost
(2013)
In this paper, we propose a new routing problem to model a highly relevant planning task in small package shipping. We consider the Prize-Collecting Vehicle Routing Problem with Non-Linear cost in its single and multi-depot version, which integrates the option of outsourcing customers to subcontractors instead of serving them with the private fleet. Thereby, a lower bound on the total customer demand to be served by the private fleet guarantees a high utilization of the fleet capacity. To represent the practical situation, where a discount is given by a subcontractor if larger amounts of packages are outsourced, subcontracting costs follow a non-linear function. The considered problem is NP-hard and we propose an Adaptive Variable Neighborhood Search algorithm to solve instances of realistic size. We propose new benchmark sets for the single and the multi-depot problem, which are adapted from test instances of the capacitated VRP and the closely related Multi-Depot VRP with Private fleet and Common carrier. In numerical studies, we investigate the performance of our algorithm on the newly generated test instances and on standard benchmark problems of related problems. Moreover, we study the effect of different cost functions and different values of the minimal demand to be served by the private fleet on the routing solutions obtained.
Insurance guarantee schemes aim to protect policyholders from the costs of insurer insolvencies. However, guarantee schemes can also reduce insurers’ incentives to conduct appropriate risk management. We investigate stock insurers’ risk-shifting behavior for insurance guarantee schemes under the two different financing alternatives: a flat-rate premium assessment versus a risk-based premium assessment. We identify which guarantee scheme maximizes policyholders’ welfare, measured by their expected utility. We find that the risk-based insurance guarantee scheme can only mitigate the insurer’s risk-shifting behavior if a substantial premium loading is present. Furthermore, the risk-based guarantee scheme is superior for improving policyholders’ welfare compared to the flat-rate scheme when the mitigating effect occurs.
Identification of the intermediates and determination of their structures in the reduction of dioxygen to water by cytochrome c oxidase (CcO) are particularly important to understanding both O2 activation and proton pumping by the enzyme. In this work, we report the products of the rapid reaction of O2 with the mixed valence form (CuA(2+), heme a(3+), heme a3(2+)-CuB(1+)) of the enzyme. The resonance Raman results show the formation of two ferryl-oxo species with characteristic Fe(IV)=O stretching modes at 790 and 804 cm(-1) at the peroxy oxidation level (PM). Density functional theory calculations show that the protein environment of the proximal H-bonded His-411 determines the strength of the distal Fe(IV)=O bond. In contrast to previous proposals, the PM intermediate is also formed in the reaction of Y167F with O2. These results suggest that in the fully reduced enzyme, the proton pumping ν(Fe(IV)=O) = 804 cm(-1) to ν(Fe(IV)=O) = 790 cm(-1) transition (P→F, where P is peroxy and F is ferryl) is triggered not only by electron transfer from heme a to heme a3 but also by the formation of the H-bonded form of the His-411-Fe(IV)=O conformer in the proximal site of heme a3. The implications of these results with respect to the role of an O=Fe(IV)-His-411-H-bonded form to the ring A propionate of heme a3-Asp-399-H2O site and, thus, to the exit/output proton channel (H2O) pool during the proton pumping P→F transition are discussed. We propose that the environment proximal to the heme a3 controls the spectroscopic properties of the ferryl intermediates in cytochrome oxidases.
Background: Understanding the coupling of O2 reduction to proton pumping by CcO requires detection of reaction intermediates.
Results: We have detected two oxoferryl intermediates at the PM oxidation state.
Conclusion: The H-bonding properties of the proximal heme a3 His ligand control the strength of the oxoferryl species.
Significance: The role of His-411, Thr-389, Gly-386, and Asp-399 residues in the proton pumping P→F transition is outlined.
We present a numerical investigation of energy and charge distributions during electron-beam-induced growth of tungsten nanostructures on SiO2 substrates by using a Monte Carlo simulation of the electron transport. This study gives a quantitative insight into the deposition of energy and charge in the substrate and in the already existing metallic nanostructures in the presence of the electron beam. We analyze electron trajectories, inelastic mean free paths, and the distribution of backscattered electrons in different compositions and at different depths of the deposit. We find that, while in the early stages of the nanostructure growth a significant fraction of electron trajectories still interacts with the substrate, when the nanostructure becomes thicker the transport takes place almost exclusively in the nanostructure. In particular, a larger deposit density leads to enhanced electron backscattering. This work shows how mesoscopic radiation-transport techniques can contribute to a model that addresses the multi-scale nature of the electron-beam-induced deposition (EBID) process. Furthermore, similar simulations can help to understand the role that is played by backscattered electrons and emitted secondary electrons in the change of structural properties of nanostructured materials during post-growth electron-beam treatments.
The TolC-like protein HgdD of the filamentous, heterocyst-forming cyanobacterium Anabaena sp. PCC 7120 is part of multiple three-component "AB-D" systems spanning the inner and outer membranes and is involved in secretion of various compounds, including lipids, metabolites, antibiotics, and proteins. Several components of HgdD-dependent tripartite transport systems have been identified, but the diversity of inner membrane energizing systems is still unknown. Here we identified six putative resistance-nodulation-cell division (RND) type factors. Four of them are expressed during late exponential and stationary growth phase under normal growth conditions, whereas the other two are induced upon incubation with erythromycin or ethidium bromide. The constitutively expressed RND component Alr4267 has an atypical predicted topology, and a mutant strain (I-alr4267) shows a reduction in the content of monogalactosyldiacylglycerol as well as an altered filament shape. An insertion mutant of the ethidium bromide-induced all7631 did not show any significant phenotypic alteration under the conditions tested. Mutants of the constitutively expressed all3143 and alr1656 exhibited a Fox(-) phenotype. The phenotype of the insertion mutant I-all3143 parallels that of the I-hgdD mutant with respect to antibiotic sensitivity, lipid profile, and ethidium efflux. In addition, expression of the RND genes all3143 and all3144 partially complements the capability of Escherichia coli ΔacrAB to transport ethidium. We postulate that the RND transporter All3143 and the predicted membrane fusion protein All3144, as homologs of E. coli AcrB and AcrA, respectively, are major players for antibiotic resistance in Anabaena sp. PCC 7120.
There is ample epidemiologic evidence for an association of chronic hepatitis C virus (HCV) infection with B-cell non-Hodgkin lymphoma (B-NHL). B-NHL subtypes most frequently associated with HCV are marginal zone lymphoma and diffuse large B-cell lymphoma. The most convincing evidence for a causal relationship between HCV infection and lymphoma development is the observation of B-NHL regression after HCV eradication by antiviral therapy (AVT). In fact, for indolent HCV-associated B-NHL, first-line AVT instead of standard immune-chemotherapy might be considered. Molecular mechanisms of HCV-NHL development are still poorly understood. Three general theories have emerged to understand the HCV-induced lymphomagenesis: (1) continuous external stimulation of lymphocyte receptors by viral antigens and consecutive proliferation; (2) HCV replication in B cells with oncogenic effect mediated by intracellular viral proteins; (3) permanent B-cell damage, e.g., mutation of tumor suppressor genes, caused by a transiently intracellular virus (“hit and run” theory). This review systematically summarizes the data on epidemiology, interventional studies, and molecular mechanisms of HCV-associated B-NHL.
The elliptic, v2, triangular, v3, and quadrangular, v4, azimuthal anisotropic flow coefficients are measured for unidentified charged particles, pions, and (anti-)protons in Pb–Pb collisions at √sNN=2.76 TeV with the ALICE detector at the Large Hadron Collider. Results obtained with the event plane and four-particle cumulant methods are reported for the pseudo-rapidity range |η|<0.8 at different collision centralities and as a function of transverse momentum, pT, out to pT=20 GeV/c. The observed non-zero elliptic and triangular flow depends only weakly on transverse momentum for pT>8 GeV/c. The small pT dependence of the difference between elliptic flow results obtained from the event plane and four-particle cumulant methods suggests a common origin of flow fluctuations up to pT=8 GeV/c. The magnitude of the (anti-)proton elliptic and triangular flow is larger than that of pions out to at least pT=8 GeV/c indicating that the particle type dependence persists out to high pT.
The PI3K/mammalian Target of Rapamycin (mTOR) pathway is often aberrantly activated in rhabdomyosarcoma (RMS) and represents a promising therapeutic target. Recent evaluation of AZD8055, an ATP-competitive mTOR inhibitor, by the Preclinical Pediatric Testing Program showed in vivo antitumor activity against childhood solid tumors, including RMS. Therefore, in the present study, we searched for AZD8055-based combination therapies. Here, we identify a new synergistic lethality of AZD8055 together with ABT-737, a BH3 mimetic that antagonizes Bcl-2, Bcl-xL, and Bcl-w but not Mcl-1. AZD8055 and ABT-737 cooperate to induce apoptosis in alveolar and embryonal RMS cells in a highly synergistic fashion (combination index < 0.2). Synergistic induction of apoptosis by AZD8055 and ABT-737 is confirmed on the molecular level, as AZD8055 and ABT-737 cooperate to trigger loss of mitochondrial membrane potential, activation of caspases, and caspase-dependent apoptosis that is blocked by the pan-caspase inhibitor Z-VAD-fmk. Similar to AZD8055, the PI3K/mTOR inhibitor NVP-BEZ235, the PI3K inhibitor NVP-BKM120 and Akt inhibitor synergize with ABT-737 to trigger apoptosis, whereas no cooperativity is found for the mTOR complex 1 inhibitor RAD001. Interestingly, molecular studies reveal a correlation between the ability of different PI3K/mTOR inhibitors to potentiate ABT-737-induced apoptosis and to suppress Mcl-1 protein levels. Importantly, knockdown of Mcl-1 increases ABT-737-induced apoptosis similar to AZD8055/ABT-737 cotreatment. This indicates that AZD8055-mediated suppression of Mcl-1 protein plays an important role in the synergistic drug interaction. By identifying a novel synergistic interaction of AZD8055 and ABT-737, our findings have important implications for the development of molecular targeted therapies for RMS.
Many snake venoms are known for their antithrombotic activity. They contain components that specifically target different platelet-activating receptors such as the collagen-binding integrin α2β1 and the von Willebrand factor receptor GPIb. In a search for an α2β1 integrin-blocking component from the venom of the habu snake (Trimeresurus flavoviridis), we employed two independent purification protocols. First, we used the integrin α2A domain, a major collagen-binding domain, as bait for affinity purification of an α2β1 integrin-binding toxin from the crude venom. Second, in parallel, we used classical protein separation protocols and tested for α2β1 integrin-inhibiting capabilities by ELISA. Using both approaches, we identified flavocetin-A as an inhibitor of α2β1 integrin. Hitherto, flavocetin-A has been reported as a GPIb inhibitor. However, flavocetin-A inhibited collagen-induced platelet aggregation even after GPIb was blocked with other inhibitors. Moreover, flavocetin-A antagonized α2β1 integrin-mediated adhesion and migration of HT1080 human fibrosarcoma cells, which lack any GPIb, on collagen. Protein chemical analyses proved that flavocetin-A binds to α2β1 integrin and its α2A domain with high affinity and in a cooperative manner, which most likely is due to its quaternary structure. Kinetic measurements confirmed the formation of a strong complex between integrin and flavocetin-A, which dissociates very slowly. This study proves that flavocetin-A, which has long been known as a GPIb inhibitor, efficiently targets α2β1 integrin and thus blocks collagen-induced platelet activation. Moreover, our findings suggest that the separation of GPIb- and α2β1 integrin-blocking members within the C-type lectin-related protein family is less strict than previously assumed.
Cellular cytotoxicity is the hallmark of NK cells mediating both elimination of virus-infected or malignant cells, and modulation of immune responses. NK cytotoxicity is triggered upon ligation of various activating NK cell receptors. Among these is the C-type lectin-like receptor NKp80 which is encoded in the human Natural Killer Gene Complex (NKC) adjacent to its ligand, activation-induced C-type lectin (AICL). NKp80-AICL interaction promotes cytolysis of malignant myeloid cells, but also stimulates the mutual crosstalk between NK cells and monocytes.
While many activating NK cell receptors pair with ITAM-bearing adaptors, we recently reported that NKp80 signals via a hemITAM-like sequence in its cytoplasmic domain. Here we molecularly dissect the NKp80 hemITAM and demonstrate that two non-consensus amino acids, in particular arginine 6, critically impair both hemITAM phosphorylation and Syk recruitment. Impaired Syk recruitment results in a substantial attenuation of cytotoxic responses upon NKp80 ligation. Reconstituting the hemITAM consensus or Syk overexpression resulted in robust NKp80-mediated responsiveness. Collectively, our data provide a molecular rationale for the restrained activation potential of NKp80 and illustrate how subtle alterations in signaling motifs determine subsequent cellular responses. They also suggest that non-consensus alterations in the NKp80 hemITAM, as commonly present among mammalian NKp80 sequences, may have evolved to dampen NKp80-mediated cytotoxic responses toward AICL-expressing cells.
Background: The activating NK receptor NKp80 triggers cytotoxicity by human NK cells via a cytoplasmic hemITAM sequence.
Results: A non-consensus hemITAM residue impairs the capacity of NKp80 to recruit Syk kinase and to trigger cytotoxicity.
Conclusion: Unlike typical hemITAM receptors, NKp80 does not efficiently recruit Syk kinase resulting in attenuated effector responses.
Significance: An attenuated cytotoxic responsiveness critically impacts on the immunomodulatory function of NKp80.
The anaerobic acetogenic bacterium Acetobacterium woodii has a novel Na(+)-translocating electron transport chain that couples electron transfer from reduced ferredoxin to NAD(+) with the generation of a primary electrochemical Na(+) potential across its cytoplasmic membrane. In previous assays in which Ti(3+) was used to reduce ferredoxin, Na(+) transport was observed, but not a Na(+) dependence of the electron transfer reaction. Here, we describe a new biological reduction system for ferredoxin in which ferredoxin is reduced with CO, catalyzed by the purified acetyl-CoA synthase/CO dehydrogenase from A. woodii. Using CO-reduced ferredoxin, NAD(+) reduction was highly specific and strictly dependent on ferredoxin and occurred at a rate of 50 milliunits/mg of protein. Most important, this assay revealed for the first time a strict Na(+) dependence of this electron transfer reaction. The Km was 0.2 mm. Na(+) could be partly substituted by Li(+). Na(+) dependence was observed at neutral and acidic pH values, indicating the exclusive use of Na(+) as a coupling ion. Electron transport from reduced ferredoxin to NAD(+) was coupled to electrogenic Na(+) transport, indicating the generation of ΔμNa(+). Vice versa, endergonic ferredoxin reduction with NADH as reductant was possible, but only in the presence of ΔμNa(+), and was accompanied by Na(+) efflux out of the vesicles. This is consistent with the hypothesis that Rnf also catalyzes ferredoxin reduction at the expense of an electrochemical Na(+) gradient. The physiological significance of this finding is discussed.
Background: Ferredoxin:NAD+-oxidoreductases (Rnf) found in many bacteria are novel ion-translocating electron transport chains.
Results: A Na+ requirement for the reaction and its reversible coupling to the transmembrane Na+ gradient are demonstrated.
Conclusion: Na+ is the coupling ion. Rnf not only generates a Na+ potential but also uses it to drive the reverse reaction.
Significance: Evidence for a function of Rnf in ferredoxin reduction is provided.
A low potential electron carrier ferredoxin (E0′ ≈ −500 mV) is used to fuel the only bioenergetic coupling site, a sodium-motive ferredoxin:NAD+ oxidoreductase (Rnf) in the acetogenic bacterium Acetobacterium woodii. Because ferredoxin reduction with physiological electron donors is highly endergonic, it must be coupled to an exergonic reaction. One candidate is NADH-dependent caffeyl-CoA reduction. We have purified a complex from A. woodii that contains a caffeyl-CoA reductase and an electron transfer flavoprotein. The enzyme contains three subunits encoded by the carCDE genes and is predicted to have, in addition to FAD, two [4Fe-4S] clusters as cofactor, which is consistent with the experimental determination of 4 mol of FAD, 9 mol of iron, and 9 mol of acid-labile sulfur. The enzyme complex catalyzed caffeyl-CoA-dependent oxidation of reduced methyl viologen. With NADH as donor, it catalyzed caffeyl-CoA reduction, but this reaction was highly stimulated by the addition of ferredoxin. Spectroscopic analyses revealed that ferredoxin and caffeyl-CoA were reduced simultaneously, and a stoichiometry of 1.3:1 was determined. Apparently, the caffeyl-CoA reductase-Etf complex of A. woodii uses the novel mechanism of flavin-dependent electron bifurcation to drive the endergonic ferredoxin reduction with NADH as reductant by coupling it to the exergonic NADH-dependent reduction of caffeyl-CoA.
Characteristically, most solid tumors exhibit an increased tumor interstitial fluid pressure (TIFP) that directly contributes to the lowered uptake of macromolecular therapeutics into the tumor interstitium. Abnormalities in the tumor-associated lymph vessels are a central brick in the development and prolonged sustaining of an increased TIFP. In the current study, vascular endothelial growth factor C (VEGF-C) was used to enhance tumor-associated lymphangiogenesis as a new mechanism to actively reduce the TIFP by increased lymphatic drainage of the tumor tissue. Human A431 epidermoid vulva carcinoma cells were inoculated in NMRI nu/nu mice to generate a xenograft mouse model. Seven days after tumor cell injection, VEGF-C was peritumorally injected to induce lymphangiogenesis. Tumor growth and TIFP was lowered significantly over time in VEGF-C-treated tumors in comparison to control or VEGF-A-treated animals. These data demonstrate for the first time that actively induced lymphangiogenesis can lower the TIFP in a xenograft tumor model and apparently reduce tumor growth. This model represents a novel approach to modulate biomechanical properties of the tumor interstitium enabling a lowering of TIFP in vivo.
Novel treatment options are needed for the successful therapy of patients with high-risk neuroblastoma. Here, we investigated the cyclin-dependent kinase (CDK) inhibitor SNS-032 in a panel of 109 neuroblastoma cell lines consisting of 19 parental cell lines and 90 sublines with acquired resistance to 14 different anticancer drugs. Seventy-three percent of the investigated neuroblastoma cell lines and all four investigated primary tumor samples displayed concentrations that reduce cell viability by 50% in the range of the therapeutic plasma levels reported for SNS-032 (<754 nM). Sixty-two percent of the cell lines and two of the primary samples displayed concentrations that reduce cell viability by 90% in this concentration range. SNS-032 also impaired the growth of the multidrug-resistant cisplatin-adapted UKF-NB-3 subline UKF-NB-3rCDDP1000 in mice. ABCB1 expression (but not ABCG2 expression) conferred resistance to SNS-032. The antineuroblastoma effects of SNS-032 did not depend on functional p53. The antineuroblastoma mechanism of SNS-032 included CDK7 and CDK9 inhibition-mediated suppression of RNA synthesis and subsequent depletion of antiapoptotic proteins with a fast turnover rate including X-linked inhibitor of apoptosis (XIAP), myeloid cell leukemia sequence 1 (Mcl-1), baculoviral IAP repeat containing 2 (BIRC2; cIAP-1), and survivin. In conclusion, CDK7 and CDK9 represent promising drug targets and SNS-032 represents a potential treatment option for neuroblastoma including therapy-refractory cases.
The antineoplastic alkaloid ellipticine is a prodrug, the pharmacological efficiency of which is dependent on its cytochrome P450 (CYP)- and/or peroxidase-mediated activation to species forming DNA adducts in target tissues. Here, we found that this compound is cytotoxic to human BHT-101, B-CPAP and 8505-C thyroid cancer cells and blocks one or more phases of cell cycle in these cancer cells. Ellipticine toxicity to the thyroid cancer cells corresponded to levels of DNA adducts generated by the CYP- and/or peroxidase-mediated ellipticine metabolites, 12-hydroxy- and 13-hydroxyellipticine, in these cells. Cultivation of all tested cells under hypoxic conditions (1 % oxygen) led to a decrease in ellipticine toxicity. Such a lower sensitivity of cells to ellipticine correlates with a decrease in the formation of ellipticine-derived DNA adducts in these cells. Using Western blotting, the expression of CYP1A1, 1B1, 3A4, thyroid peroxidase (TPO), cyclooxygenase-1 (COX-1) and cytochrome b5, the enzymes that catalyze, and/or influence ellipticine metabolism, was investigated in the cancer cells. Furthermore, the effects of ellipticine treatment on the expression levels of these proteins in thyroid cancer cells were also examined. The results indicate that the highest expression levels of cytochrome b5 together with CYP1A1 and 3A4 determine the highest DNA adduct formation and cytotoxicity of ellipticine in B-CPAP cells. They also demonstrate that formation of covalent DNA adducts by ellipticine is the predominant mechanism responsible for its cytotoxicity in studied cells.
The gauge principle is fundamental in formulating the Standard Model. Fermion–gauge-boson couplings are the inescapable consequence and the primary determining factor for observable phenomena. Vertices describing such couplings are simple in perturbation theory and yet the existence of strong-interaction bound-states guarantees that many phenomena within the Model are nonperturbative. It is therefore crucial to understand how dynamics dresses the vertices and thereby fundamentally alters the appearance of fermion–gauge-boson interactions. We consider the coupling of a dressed-fermion to an Abelian gauge boson, and describe a unified treatment and solution of the familiar longitudinal Ward–Green–Takahashi identity and its less well known transverse counterparts. Novel consequences for the dressed-fermion–gauge-boson vertex are exposed.
Previous experimental measurements from nuclear collisions have indicated modifications of jets by interaction with the medium created in the collision. Observables from particle correlations in the ALICE detector continue to provide access to key properties of the hot deconfined nuclear matter. New results from two- and three-particle number and transverse momentum correlations are discussed. Specifically, correlation function properties are characterized as a function of transverse momentum and centrality and for different charge combinations. Fourier decompositions are performed, identified particle ratios are studied in the jet-like peak and in the bulk, and the away-side shape is looked at in three-particle correlations.
The proportion of elderly women in the population is rising, and in tandem, the incidence of breast cancer rises with age. Because of health and tolerability concerns, as well as life expectancy, physicians may be reluctant to advise a standard treatment regimen for elderly patients with metastatic breast cancer. To elucidate this issue, we performed a literature review of clinical studies that included women with metastatic breast cancer who were over the age of 65. Our results show that although little clinical evidence exists, what is available suggests that standard treatment is tolerated and beneficial for patients meeting certain criteria. A geriatric assessment may identify specific patient groups (independent, dependent, or frail) and thereby guide treatment. Treatment recommendations for elderly patients with metastatic breast cancer are sparse, although first-line endocrine treatment, usually aromatase inhibitors or tamoxifen, is recommended for hormone-sensitive disease. In general, the evidence from clinical studies suggests that aromatase inhibitors are more effective than either tamoxifen or megestrol acetate as first- or second-line treatment in postmenopausal women with metastatic breast cancer. Ultimately, quality of life, treatment effects, and comorbidities are important aspects in this population and may guide treatment choice. To provide evidence-based treatment guidance, future clinical trials should include more patients over the age of 65 years.
The ALICE detector is ideally suited to study the production of anti- and hyper-matter due to its excellent particle identification capabilities. The measurement of the He¯4-nucleus in Pb–Pb collisons at sNN=2.76TeV is presented. We further show the performance for the reconstruction of the (anti-)hypertriton in the decay to He3+π− (He¯3+π+). In addition to this, two searches have been performed, one for the H-Dibaryon →Λpπ− and one for the Λn bound state (Λn¯→d¯π+). No signals are observed for these exotic states and upper limits have been determined.
In high-energy nuclear collisions, heavy quark potential at finite temperature controls the quarkonium suppression. Including the relaxation of the medium induced by the relative velocity between quarkonia and the deconfined expanding matter, the Debye screening is reduced and the quarkonium dissociation takes place at a higher temperature. As a consequence of the velocity-dependent dissociation temperature, the quarkonium suppression at high transverse momentum is significantly weakened in high-energy nuclear collisions at RHIC and LHC.
We investigate the modification of the pion self-energy at finite temperature due to its interaction with a low-density, isospin-symmetric nuclear medium embedded in a constant magnetic background. To one loop, for fixed temperature and density, we find that the pion effective mass increases with the magnetic field. For the π−, interestingly, this happens solely due to the trivial Landau quantization shift ∼|eB|, since the real part of the self-energy is negative in this case. In a scenario in which other charged particle species are present and undergo an analogous trivial shift, the relevant behavior of the effective mass might be determined essentially by the real part of the self-energy. In this case, we find that the pion mass decreases by ∼10% for a magnetic field |eB|∼mπ2, which favors pion condensation at high density and low temperatures.
In the stomach, neoplastic lesions often arise in the setting of precursor conditions such as gastritis, intestinal metaplasia, or adenomatous lesions. Biopsies may, therefore, underestimate disease severity or even miss the diagnosis (sampling error). Endomicroscopy is able to visualize typical features of such pathologies. It enables in vivo microscopy of gastritis with definition of enhanced vascularity and vascular leakage, but the typical cobblestone appearance of the gastric mucosa is preserved. The presence of intestinal metaplasia is confirmed by columnar absorptive cells with brush border and goblet cells within villiform foveolar epithelium. Gastric neoplasia is characterized by crowded glands with intraluminal folding and glandular budding and branching accompanied by increased density of dilated and distorted capillaries. Finally, in gastric cancer, gland and overall mucosal architecture is progressively lost. These features are shown side by side with white-light endoscopic findings. Endomicroscopy is used in such a setting to rapidly screen larger areas (optical biopsies) and subsequently target tissue sampling to areas with highly suspicious microscopic patterns. In experienced hands, it therefore constitutes an important part especially in the presence of neoplastic lesions within noncircumscript gastric premalignant conditions. This article is part of an expert video encyclopedia.
Stent insertion is an established technique of endoscopic retrograde cholangiopancreatography (ERCP) to treat symptomatic malignant or benign biliary strictures, and stent placement is accomplished by using the over-the-wire (OTW) method. In some cases, however, it might be challenging and sometimes time consuming to pass a complex biliary stricture with the guidewire. Stent-exchange technique with a guidewire left in place during stent removal might therefore be helpful to guarantee successful and time-sparing interventions.
A simple method is presented to remove the stent with the guidewire left in place, using the OTW stent-exchange method in ERCP. This technique simplifies stent OTW exchange by using a simple endoscopy snare. This article is part of an expert video encyclopedia.
Dieulafoy's lesion (DL) is a rare source of gastrointestinal tract bleeding that may occur at any site in the gastrointestinal tract and may be difficult to detect by endoscopy. DL is characterized by a large, tortuous arteriole in the submucosa. This is a case of duodenal DL that is detected and treated by endoscopy. This article is part of an expert video encyclopedia.
This is the case report of a 58-year-old male patient who presented with recurring abdominal pain of 4 months duration. He had undergone multiple investigations including upper and lower gastrointestinal tract endoscopies and diagnostic laparoscopy, but there were no significant findings detected.
Capsule endoscopy revealed a submucosal small bowel tumor that was suspected to originate from the distal third of the small bowel. Surgery was indicated and a highly differentiated neuroendocrine tumor was found at laparotomy at the distal ileum. An ileocecal resection was performed confirming a neuroendocrine tumor of the small bowel (G2T2N1M1). This article is part of an expert video encyclopedia.
A rare cause of recurrent melena was identified by capsule endoscopy: arteriovenous malformation
(2013)
Small bowel endoscopy is indicated for patients with an unidentified bleeding site in esophagogastroduodenoscopy and ileocolonoscopy and symptoms of intestinal blood loss or unexplained anemia. In approximately two-thirds of these cases, capsule endoscopy (CE) detects a lesion within the small bowel that explains the patient's symptoms.
The case of an 80-year-old female patient with recurrent melena and anemia is presented here by the authors. Endoscopy of the upper gastrointestinal tract as well as ileocolonoscopy did not show any pathological findings. CE revealed an area with abnormal mucosa in the middle third of the small bowel, which was strongly suspected of having malignant origin. Surgical exploration led to resection of a small jejunal segment with a palpable mass and increased blood flow. Surprisingly, the final diagnosis determined by the pathologist was arteriovenous malformation (AVM). This article is part of an expert video encyclopedia.
The author presents the case of a patient with severe bleeding from a duodenal ulcer that could not be controlled by endoscopic application of metal clips and injection of fibrin glue. Angiographic embolization with placement of coils into the feeding vessel stopped the bleeding. However, 3 days later, a fistula emerged from coil material penetrating into the dorsal duodenum and a peritoneal leakage developed. The fistula was completely closed by placing an over-the-scope clip on the enteral opening of the fistula. This article is part of an expert video encyclopedia.
Small bowel varices may be found in less than 5% of patients with suspected small bowel bleeding. These varices are associated with portal hypertension or thrombosis of mesenteric venous vessels and with altered abdominal vascular anatomy with or without prior small bowel surgery. In bleeding small bowel varices, therapeutic options include endoscopic injection of tissue adhesives, endovascular approaches such as balloon-occluded retrograde transvenous or percutaneous obliteration and transjugular intrahepatic portosystemic shunt, and surgical resection. This is a case report of a 53-year-old patient with ethylic liver cirrhosis who presented with severe, life-threatening hematochezia due to small bowel varices. This article is part of an expert video encyclopedia.
Peutz–Jeghers syndrome (PJS) is a rare autosomal-dominant inherited disorder characterized by gastrointestinal hamartomas, mucocutaneous pigmentation, and an elevated cancer risk. Moreover, intussusception risk may be as high as 50% at the age of 20 years and is caused by large polyps. There is some evidence that endoscopic surveillance of PJS patients with removal of small intestinal polyps with a diameter of more than 15 mm efficiently prevents intussusceptions. In recent years, capsule endoscopy (CE) has largely replaced small-bowel radiography techniques to screen for small-bowel polyps. Magnetic resonance imaging may be equally efficient as CE for screening of large polyps. Balloon enteroscopy may be used for endoscopic snare resection of polyps. This article is part of an expert video encyclopedia.
The small intestine is a part of the gastrointestinal tract in which digestion and absorption of nutrients takes place. The small bowel follows the stomach and is followed by the large intestine, reaching from the pylorus to the valve of Bauhin and is separated into the duodenum, the jejunum, and the ileum.
Capsule endoscopy (CE) has the potential to offer a perfect overview of the small-bowel mucosa and complete visualization of the entire small bowel is achieved in most cases. In this video, there is an overview offered on normal findings in small-bowel CE and typical anatomical landmarks are indicated. This article is part of an expert video encyclopedia.
This is an example of capsule endoscopy (CE) revealing terminal ileitis in an young male patient with recurrent abdominal pain who had previously been investigated with colonoscopy and esophagogastroduodenoscopy without any significant findings. CE revealed severe inflammation of the terminal ileum. This article is part of an expert video encyclopedia.
Small bowel tumors are detected in approximately 10% of patients with small bowel endoscopies for obscure or overt mid-intestinal bleeding. Small bowel tumors may be of malignant or benign etiology. Malignant etiologies include adenocarcinoma, neuroendocrine tumors, or lymphoma, whereas benign lesions are typically lipomas, inflammatory polyps, or adenomas. Within the group of nonneoplastic lesions inflammatory polyps are most frequent. Significant bleeding and bowel obstruction due to intussusception might occur, and surgical or endoscopic treatment has been reported for symptomatic patients. A case is demonstrated with an inflammatory fibroid polyp detected by capsule endoscopy and confirmed by balloon enteroscopy. This article is part of an expert video encyclopedia.
Operatively altered anatomy such as Billroth II gastroenterostomy represents a challenge in endoscopic retrograde cholangiopancreatography and might require dedicated instruments. In this article, the authors demonstrate the technique of endoscopic retrograde cholangiography and sphincterotomy in a patient with Billroth's operation-II. Sphincterotomy is performed with a specially designed Billroth papillotome to enable papillotomy in the direction of the papillary roof. This article is part of an expert video encyclopedia.
In this article, the video demonstrated is an example of a 76-year-old male patient who presented with recurrent intestinal bleeding of unknown origin at the university hospital. Previously performed upper and lower gastrointestinal tract endoscopy did not reveal a bleeding lesion. Capsule endoscopy revealed small-bowel angiectasia that were treated by argon plasma coagulation at subsequent balloon enteroscopy. This article is part of an expert video encyclopedia.
Small bowel endoscopy is indicated for patients with an unidentified bleeding site in esophagogastroduodenoscopy and ileocolonoscopy and symptoms of intestinal blood loss or unexplained anemia. In approximately two-thirds of these cases, capsule endoscopy (CE) detects a lesion within the small bowel that explains the patient's symptoms. In few cases, though, lesions outside of the small bowel might be revealed by CE. Therefore, attention to all intestines that are visualized by CE might be necessary not to overlook bleeding sites that had not been discovered by prior flexible endoscopy.
Here the case of a 71-year-old male patient with unexplained anemia is presented by the authors. Small-bowel CE revealed minor bleeding from a neoplastic mass in the cecum. The final diagnosis of an adenocarcinoma of the ascending colon was established after the patient underwent a right hemicolectomy. This article is part of an expert video encyclopedia.
Small bowel endoscopy is indicated for patients with an unidentified bleeding site in esophago-gastro-duodenoscopy and ileo-colonoscopy and symptoms of intestinal blood loss or unexplained anemia. In approximately two-thirds of these cases, capsule endoscopy (CE) detects a lesion within the small bowel that explains the patient's symptoms. In few cases, though, lesions outside of the small bowel might be revealed by CE. Therefore, attention to all intestines that are visualized by CE might be necessary not to overlook bleeding sites that had not been discovered by prior flexible endoscopy.
The authors present the case of a 71-year-old male patient who presented to their outpatient clinic for unexplained anemia. Small bowel CE revealed minor bleeding from an adenocarcinoma in the cecum. This article is part of an expert video encyclopedia.
Operatively altered anatomy might provide a challenge for endoscopic retrograde cholangiopancreatography. However, with the support of the balloon-assisted enteroscopy technique the access route to the biliary system even in long-limb Roux-Y anastomosis is feasible in most cases.
In this video case report, an 81-year-old woman was symptomatic for stone obstruction of the common bile duct (CBD). Complete gastrectomy had been performed in this patient for stomach cancer many years earlier. Balloon-assisted enteroscopy was used for retrograde access of the duodenum via a Roux-Y anastomosis. There was major difficulty in intubating the CBD via the native papilla in this case because access was prevented by the tangential approach of the enteroscope. After performing an incomplete papillectomy, the insertion of a guidewire into the CBD was feasible and the bile duct stone was removed. This article is part of an expert video encyclopedia.
Here the authors report the case of an elderly woman who had upper abdominal pain, upper gastrointestinal hemorrhage, and jaundice (a symptomatic triad termed the ‘Quincke’ triad) a few days after endoscopic sphincterotomy. Abdominal ultrasonography demonstrated an echo-rich filling of the choledochus consistent with hemobilia. Endoscopic retrograde cholangiography was immediately performed and blood clots were removed from the common bile duct. A nasobiliary catheter was placed to irrigate the bile duct for prevention of recurring obstruction of the bile ducts from blood clots. Further follow-up of the patient was uneventful. This article is part of an expert video encyclopedia.
Small-bowel tumors are rare and account for approximately 5% of all gastrointestinal tumors. Approximately 65% of small-bowel tumors are malignant, and approximately 40% of these tumors are adenocarcinomas. Similar to colorectal adenocarcinoma, premalignant adenomas of the small bowel may progress to carcinoma. This occurs both sporadically and in the context of hereditary tumor syndromes such as familial adenomatous polyposis or hereditary nonpolyposis colorectal cancer (Lynch syndrome). Herein cases with small-bowel adenocarcinomas visualized with both capsule endoscopy and double-balloon enteroscopy are presented. This article is part of an expert video encyclopedia.
The production cross section of electrons from semileptonic decays of beauty hadrons was measured at mid-rapidity (|y|<0.8) in the transverse momentum range 1<pT<8 GeV/c with the ALICE experiment at the CERN LHC in pp collisions at a center of mass energy √s=7 TeV using an integrated luminosity of 2.2 nb−1. Electrons from beauty hadron decays were selected based on the displacement of the decay vertex from the collision vertex. A perturbative QCD calculation agrees with the measurement within uncertainties. The data were extrapolated to the full phase space to determine the total cross section for the production of beauty quark–antiquark pairs.
The inclusive transverse momentum (pT) distributions of primary charged particles are measured in the pseudo-rapidity range |η|<0.8 as a function of event centrality in Pb–Pb collisions at √sNN=2.76 TeV with ALICE at the LHC. The data are presented in the pT range 0.15<pT<50 GeV/c for nine centrality intervals from 70–80% to 0–5%. The results in Pb–Pb are presented in terms of the nuclear modification factor RAA using a pp reference spectrum measured at the same collision energy. We observe that the suppression of high-pT particles strongly depends on event centrality. The yield is most suppressed in central collisions (0–5%) with RAA≈0.13 at pT=6–7 GeV/c. Above pT=7 GeV/c, there is a significant rise in the nuclear modification factor, which reaches RAA≈0.4 for pT>30 GeV/c. In peripheral collisions (70–80%), only moderate suppression (RAA=0.6–0.7) and a weak pT dependence is observed. The measured nuclear modification factors are compared to other measurements and model calculations.
Long-range angular correlations on the near and away side in p–Pb collisions at √sNN=5.02 TeV
(2013)
Angular correlations between charged trigger and associated particles are measured by the ALICE detector in p–Pb collisions at a nucleon–nucleon centre-of-mass energy of 5.02 TeV for transverse momentum ranges within 0.5<pT,assoc<pT,trig<4 GeV/c. The correlations are measured over two units of pseudorapidity and full azimuthal angle in different intervals of event multiplicity, and expressed as associated yield per trigger particle. Two long-range ridge-like structures, one on the near side and one on the away side, are observed when the per-trigger yield obtained in low-multiplicity events is subtracted from the one in high-multiplicity events. The excess on the near-side is qualitatively similar to that recently reported by the CMS Collaboration, while the excess on the away-side is reported for the first time. The two-ridge structure projected onto azimuthal angle is quantified with the second and third Fourier coefficients as well as by near-side and away-side yields and widths. The yields on the near side and on the away side are equal within the uncertainties for all studied event multiplicity and pT bins, and the widths show no significant evolution with event multiplicity or pT. These findings suggest that the near-side ridge is accompanied by an essentially identical away-side ridge.
We investigate the phase structure of strongly interacting matter at non-vanishing isospin before the onset of pion condensation in the framework of the unquenched Polyakov–Quark-Meson model with 2+1 quark flavors. We show results for the order parameters and all relevant thermodynamic quantities. In particular, we obtain a moderate change of the pressure with isospin at vanishing baryon chemical potential, whereas the chiral condensate decreases more appreciably. We compare the effective model to recent lattice data for the decrease of the pseudo-critical temperature with the isospin chemical potential. We also demonstrate the major role played by the value of the pion mass in the curvature of the transition line, and the need for lattice results with a physical pion mass. Limitations of the model at nonzero chemical potential are also discussed.
The width of the ω meson in cold nuclear matter is computed in a hadronic many-body approach, focusing on a detailed treatment of the medium modifications of intermediate πρ states. The π and ρ propagators are dressed by their self-energies in nuclear matter taken from previously constrained many-body calculations. The pion self-energy includes Nh and Δh excitations with short-range correlations, while the ρ self-energy incorporates the same dressing of its 2π cloud with a full 3-momentum dependence and vertex corrections, as well as direct resonance-hole excitations; both contributions were quantitatively fit to total photo-absorption spectra and πN→ρN scattering. Our calculations account for in-medium decays of type ωN→πN(⁎),ππN(Δ), and 2-body absorptions ωNN→NN(⁎),πNN. This causes deviations of the in-medium ω width from a linear behavior in density, with important contributions from spacelike ρ propagators. The ω width from the ρπ cloud may reach up to 200 MeV at normal nuclear matter density, with a moderate 3-momentum dependence. This largely resolves the discrepancy of linear T–ϱ approximations with the values deduced from nuclear photoproduction measurements.
Herbal hepatotoxicity is a rare but highly disputed disease because numerous confounding variables may complicate accurate causality assessment. Case evaluation is even more difficult when the WHO global introspection method (WHO method) is applied as diagnostic algorithm. This method lacks liver specificity, hepatotoxicity validation, and quantitative items, basic qualifications required for a sound evaluation of hepatotoxicity cases. Consequently, there are no data available for reliability, sensitivity, specificity, positive and negative predictive value. Its scope is also limited by the fact that it cannot discriminate between a positive and a negative causality attribution, thereby stimulating case overdiagnosing and overreporting. The WHO method ignores uncertainties regarding daily dose, temporal association, start, duration, and end of herbal use, time to onset of the adverse reaction, and course of liver values after herb discontinuation. Insufficiently considered or ignored are comedications, preexisting liver diseases, alternative explanations upon clinical assessment, and exclusion of infections by hepatitis A-C, cytomegalovirus (CMV), Epstein-Barr virus (EBV), herpes simplex virus (HSV), and varicella zoster virus (VZV). We clearly prefer as alternative the scale of CIOMS (Council for International Organizations of Medical Sciences) which is structured, quantitative, liver specific, and validated for hepatotoxicity. In conclusion, causality of herbal hepatotoxicity is best assessed by the liver specific CIOMS scale validated for hepatotoxicity rather than the obsolete WHO method that is liver unspecific and not validated for hepatotoxicity. CIOMS based assessments will ensure the correct diagnosis and exclude alternative diagnosis that may require other specific therapies.
For the pathologist, the diagnosis of drug induced liver injury (DILI) is challenging, because histopathological features mimic all primary hepatic and biliary diseases, lacking changes that are specific for DILI. Therefore, in any patient of suspected DILI who underwent liver biopsy, the pathologist will assure the clinician that the observed hepatic changes are compatible with DILI, but this information is less helpful due to lack of specificity. Rather, the pathologist should assess liver biopsies blindly, without knowledge of prior treatment by drugs. This will result in a detailed description of the histological findings, associated with suggestions for potential causes of these hepatic changes. Then, it is up to the physician to reassess carefully the differential diagnoses, if not done before. At present, liver histology is of little impact establishing the diagnosis of DILI with the required degree of certainty, and this shortcoming also applies to herb induced liver injury (HILI). To reach at the correct diagnoses of DILI and HILI, clinical and structured causality assessments are therefore better approaches than liver histology results obtained through liver biopsy, an invasive procedure with a low complication rate.
The relationship between achievement of a pathologic complete response (pCR) and favorable long-term outcome varies among breast cancer subtypes. We aimed to highlight which neoadjuvant treatment strategy could be most successful in each breast cancer subtype. A recent FDA meta-analysis on randomized neoadjuvant breast cancer trials suggests that the survival differences of patients with or without a pCR were less pronounced in luminal A-like tumors, despite the overall favorable prognosis of these patients. Moreover, even though the strong prognostic effect of pCR in HER2 positive and TNBC, the NOAH study was the only trial which showed a trend in surrogacy of pCR for long-term outcome in HER2-positive subtype. Results from GeparTrio study suggest that patients with hormone-positive tumors might need a response-guided approach, with either an intensification of treatment in case of an early response or a change to other chemotherapy in case of no early response. Furthermore, data from German neoadjuvant trials confirm that an increasing number of chemotherapy cycles is associated with a higher pCR rate, especially in patients with HER2-positive/hormone-positive tumors. In line with these suggestions, Tryphaena study showed a pCR rate that exceeding the 60% threshold, the highest pCR results presented in a large multicenter study. In TNBC, the highest pCR rate in the German neoadjuvant studies was obtained with the simultaneous application of docetaxel, doxorubicin and cyclophosphamide for 6 cycles. However, as shown in GaparQuinto and NSABP 40 trials, treatment effect in TNBC might be further maximized by adding bevacizumab, and two randomized neoadjuvant trials are expected this year to report data on the efficacy of carboplatin.
Hepatology highlights
(2013)
Cognition requires the dynamic modulation of effective connectivity, i.e. the modulation of the postsynaptic neuronal response to a given input. If postsynaptic neurons are rhythmically active, this might entail rhythmic gain modulation, such that inputs synchronized to phases of high gain benefit from enhanced effective connectivity. We show that visually induced gamma-band activity in awake macaque area V4 rhythmically modulates responses to unpredictable stimulus events. This modulation exceeded a simple additive superposition of a constant response onto ongoing gamma-rhythmic firing, demonstrating the modulation of multiplicative gain. Gamma phases leading to strongest neuronal responses also led to shortest behavioral reaction times, suggesting functional relevance of the effect. Furthermore, we find that constant optogenetic stimulation of anesthetized cat area 21a produces gamma-band activity entailing a similar gain modulation. As the gamma rhythm in area 21a did not spread backwards to area 17, this suggests that postsynaptic gamma is sufficient for gain modulation.
We examine the photoinduced excited state dynamics of pyrene modified adenosine, a versatile probe for folding and hybridization of ribonucleic acids. Measurements in different solvents revealed complex ultrafast dynamics, but high robustness since the overall fluorescence quantum yield (Φf) is hardly affected. The result is a strong fluorescent RNA-probe whose spectral properties change in a defined way upon environmental changes.
Problems of production and study of new neutron-enriched heavy nuclei are discussed. Low-energy multinucleon transfer reactions are shown to be quite appropriate for this purpose. Reactions with actinide beams and targets are of special interest for synthesis of new neutron-enriched transfermium nuclei and not-yet-known nuclei with closed neutron shell N = 126 having the largest impact on the astrophysical r-process. The estimated cross sections for the production of these nuclei look very promising for planning such experiments at currently available accelerators. These experiments, however, are rather expensive and difficult to perform because of low intensities of the massive projectile beams and problems of separating and detecting the heavy reaction products. Thus, realistic predictions of the corresponding cross sections for different projectile-target combinations are definitely required. Some uncertainty still remains in the values of several parameters used for describing the low-energy nuclear dynamics. This uncertainty does not allow one to perform very accurate predictions for the productions of new heavier-than-target (trans-target) nuclei in multinucle on transfer reactions. Nevertheless these predictions are rather promising (large cross sections) to start such experiments at available accelerators if the problem of separation of heavy transfer reaction products would be solved.
Above 1 MeV of incident neutron energy the fission fragment angular distribution (FFAD) has generally a strong anisotropic behavior due to the combination of the incident orbital momentum and the intrinsic spin of the fissioning nucleus. This effect has to be taken into account for the efficiency estimation of devices used for fission cross section measurements. In addition it bears information on the spin deposition mechanism and on the structure of transitional states. We designed and constructed a detection device, based on Parallel Plate Avalanche Counters (PPAC), for measuring the fission fragment angular distributions of several isotopes, in particular 232Th. The measurement has been performed at n_TOF at CERN taking advantage of the very broad energy spectrum of the neutron beam. Fission events were recognized by back to back detection in coincidence in two position-sensitive detectors surrounding the targets. The detection efficiency, depending mostly on the stopping of fission fragments in backings and electrodes, has been computed with a Geant4 simulation and validated by the comparison to the measured case of 235U below 3 keV where the emission is isotropic. In the case of 232Th, the result is in good agreement with previous data below 10 MeV, with a good reproduction of the structures associated to vibrational states and the opening of second chance fission. In the 14 MeV region our data are much more accurate than previous ones which are broadly scattered.
It can hardly be disputed that the theme of popularity is central to the Enlightenment. Popularity is the sociality equivalent to the individual appeal: 'Dare to know.' Parallel to this runs the following imperative: 'Dare to encourage your neighbour and your fellow man and woman to think on their own – even though they do not belong to the erudite elite.' It is also undeniable that Romantic authors and philosophers polemically attempted to tear down the popularity project of the Enlightenment, their main criticism being its tendency towards mediocrity. It is less well known that Romantic authors and philosophers themselves, around the turn of the nineteenth century, made popularity their central concern. To quote Friedrich Schlegel in the journal Athenaeum: 'The time of popularity has come.' This article explores the Romantics' alternative conception of popularity, with especial reference to Johann Gottlieb Fichte and the Grimm Brothers. To this end, it is helpful to reconstruct the background of the Romantic attempt to create an independent concept of popularity: the debate between Immanuel Kant and the German popular philosopher Christian Garve on the necessity, possibilities, and limits of popularity.
The influence and power of some OECD states is under threat but China appears to remain astonishingly flexible, economically potent, and politically strong. How accurate is this view? To answer this question, major aspects of Chinese economic regulation that were adopted in the country’s progress towards capitalist modernization are examined. The analysis requires a historical reconstruction of how China changed the way it intervenes economically and politically, especially with regard to the institutions of the central state. Such a reconstruction reveals that, since the 1990s, the central state has indeed increased its steering capacities. These capacities have a distinctive basis that includes acceptance of a state-centered approach, idiosyncratic innovation policies taking place in the "shadow" of the state’s hierarchy, and the ongoing influence of the communist party. An all-embracing controlling power is, however, not detectable. What does exist in China’s competition-driven system of “statecapitalist” regulation, is a set of limits on the state’s capacity to govern.
Marginality does not mean isolation. In Africa where people are permanently on the move in search, inter alia, of a 'better elsewhere', marginality means disconnection to obvious possibilities and the invisibility of the myriad connections that make life possible for the ordinarily sidestepped. This book is about the workings of networks of the mobile in Africa, a continent usually associated with the 'global shadows' of the world. How do changes in the possibilities for communication, with the recent hype of mobile technology, influence the social and economic dynamics in Africa's mobile margins? To what extent is the freedom associated with new Information and Communication Technologies reality or disillusion for people dwelling in the margins? Are ordinary Africans increasingly Side@Ways? How social are these emergent Side@Ways? Contributions to answering these and related questions are harvested from ethnographic insights by team members of the WOTRO funded 'Mobile Africa revisited' research programme hosted by the African Studies Centre, Leiden, The Netherlands.
Vestiges
(2013)
The poems in this collection are adequate, with great lines. The rhythm is stimulating to all the five senses thanks to the use of multiple images. A lot of imagery in Vestiges gives a picture of a war front after a ferocious battle. The objects, animals, and images in the poems disorient and lead the reader to focusing on putting flesh to the bones than just getting the juice of the poems... The rhythm more than anything else carries the reader through this chaotic tableau painted in Vestiges. In a way, this comes across as a substantiation of the poet's vision of our world and an explanation as to why he considers this collection as a skeleton; and precisely skeletons left by the ravages of war. Is the poet's world and ours a field of ruins and topsy-turvydom to which we are all blind? The answer is yours.
The Green Cross of Kafira
(2013)
In his last play published posthumously the late Francis Imbuga presents the dramatic dialogue of his characters as mind games. In addition to using a narrator, Sikia Macho, to fill us in on the broken politics of Kafira, centring around detention without trial, Imbuga deliberately delays the inciting action, the formation of the Green Party of Kafira which then challenges the hitherto political monolith called the National Party. The candidate of the new party, former detainee Pastor Mgei, wins the election, and thereby dethrones the so-called Chief of Chiefs. In The Green Cross of Kafira, Imbuga, with a renewed sense of urgency, addresses the theme of dictatorship in Africa, and completes his trilogy of the Kafira plays which begins with Betrayal in the city followed by Man of Kafira.
Thousands of Cameroonian women played an essential role in the radically anti-colonial nationalist movement led by the Union of the Populations of Cameroon (UPC): they were the women of the Democratic Union of Cameroonian Women (UDEFEC). Drawing on women nationalists' petitions to the United Nations, one of the largest collections of political documents written by African women during the decolonization era, as well as archival research and oral interviews, this work shows how UDEFEC transcended ethnic, class, education and social divides, and popularized nationalism in both urban and rural areas through the Trust Territories of the Cameroons under French and British administration. Foregrounding issues such as economic autonomy and biological and agricultural fertility, UDEFEC politics wove anti-imperial democracy and notions of universal human rights into locally rooted political cultures and histories. UDEFEC's history sheds light on the essential components of women's successful political mobilization in Africa, and contributes to the discussion of women's involvement in nationalist movements in formerly colonized territories.
This is a story of Nigeria, told from the inside. After a successful career in the private sector, Nasir El-Rufai rose to the top ranks of Nigeria's political hierarchy, serving first as the privatization czar at the Bureau for Public Enterprises and then as Minister of the Federal Capital Territory of Abuja under former President Olesegun Obasanjo. In this tell-all memoir, El-Rufai reflects on a life in public service to Nigeria, the enormous challenges faced by the country, and what can be done while calling on a new generation of leaders to take the country back from the brink of destruction. The shocking revelations disclosed by El-Rufai about the formation of the current leadership and the actions of prominent statesmen make this memoir required reading for anyone seeking to understand the dynamics of power politics in Africa's most populous nation.
Most Nigerians, when they talk about Nigeria, will always refer to her with bubbling jingoism as 'giant of Africa' or 'our great nation, Nigeria' but fail to ask 'giant of what?' Goodness or Evil? Productivity or Consumption? Success or Failure? Meritocracy or Mediocrity? Hollowness or Substance? Capturing the 'mood of the nation' this book offers diagnosis on the country which are broad-based, instructive and well presented. Part I outlines the developmental stages of Nigeria while Part II gives an in depth diagnosis of the major problems besetting Nigeria, following Part III gives examples of nations and leadership traits Nigeria could emulate.
An important feature of Ghanaian tertiary education is the foundational African Studies Programme which was initiated in the early 1960s. Unfortunately hardly any readers exist which bring together a body of knowledge on the themes, issues and debates which inform and animate research and teaching in African Studies particularly on the African continent. This becomes even more important when we consider the need for knowledge on Africa that is not Eurocentric or sensationalised, but driven from internal understandings of life and prospects in Africa. Dominant representations and perceptions of Africa usually depict a continent in crisis. Rather than buying into external representations of Africa, with its 'lacks' and aspirations for Western modernities, we insist that African scholars in particular should be in the forefront of promoting understanding of the pluri-lingual, overlapping, and dense reality of life and developments on the continent, to produce relevant and usable knowledge. Continuing and renewed interest in Africa's resources, including the land mass, economy, minerals, visual arts and performance cultures, as well as bio-medical knowledge and products, by old and new geopolitical players, obliges African scholars to transcend disciplinary boundaries and to work with each other to advance knowledge and uses of those resources in the interests of Africa's people.