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There are strong indications that particles containing secondary organic aerosol (SOA) exhibit amorphous solid or semi-solid phase states in the atmosphere. This may facilitate deposition ice nucleation and thus influence cirrus cloud properties. However, experimental ice nucleation studies of biogenic SOA are scarce. Here, we investigated the ice nucleation ability of viscous SOA particles.
The SOA particles were produced from the ozone initiated oxidation of α-pinene in an aerosol chamber at temperatures in the range from −38 to −10 ◦C at 5–15 % relative humidity with respect to water to ensure their formation in a highly viscous phase state, i.e. semi-solid or glassy. The ice nucleation ability of SOA particles with different sizes was investigated with a new continuous flow diffusion chamber. For the first time, we observed heterogeneous ice nucleation of viscous α-pinene SOA in the deposition mode for ice saturation ratios between 1.3 and 1.4 significantly below the homogeneous freezing limit. The maximum frozen fractions found at temperatures between −36.5 and −38.3 °C ranged from 6 to 20 % and did not depend on the particle surface area. Global modelling of monoterpene SOA particles suggests that viscous biogenic SOA particles are indeed present in regions where cirrus cloud formation takes place. Hence, they could make up an important contribution to the global ice nuclei (IN) budget.
There are strong indications that particles containing secondary organic aerosol (SOA) exhibit amorphous solid or semi-solid phase states in the atmosphere. This may facilitate heterogeneous ice nucleation and thus influence cloud properties. However, experimental ice nucleation studies of biogenic SOA are scarce. Here, we investigated the ice nucleation ability of viscous SOA particles.
The SOA particles were produced from the ozone initiated oxidation of α-pinene in an aerosol chamber at temperatures in the range from −38 to −10 °C at 5–15 % relative humidity with respect to water to ensure their formation in a highly viscous phase state, i.e. semi-solid or glassy. The ice nucleation ability of SOA particles with different sizes was investigated with a new continuous flow diffusion chamber. For the first time, we observed heterogeneous ice nucleation of viscous α-pinene SOA for ice saturation ratios between 1.3 and 1.4 significantly below the homogeneous freezing limit. The maximum frozen fractions found at temperatures between −39.0 and −37.2 °C ranged from 6 to 20 % and did not depend on the particle surface area. Global modelling of monoterpene SOA particles suggests that viscous biogenic SOA particles are indeed present in regions where cirrus cloud formation takes place. Hence, they could make up an important contribution to the global ice nucleating particle budget.
Cloud microphysical processes involving the ice phase in tropospheric clouds are among the major uncertainties in cloud formation, weather and General Circulation Models (GCMs). The simultaneous detection of aerosol particles, liquid droplets, and ice crystals, especially in the small cloud-particle size range below 50 µm, remains challenging in mixed phase, often unstable ice-water phase environments. The Cloud Aerosol Spectrometer with Polarisation (CASPOL) is an airborne instrument that has the ability to detect such small cloud particles and measure their effects on the backscatter polarisation state. Here we operate the versatile Cosmics-Leaving- OUtdoor-Droplets (CLOUD) chamber facility at the European Organisation for Nuclear Research (CERN) to produce controlled mixed phase and other clouds by adiabatic expansions in an ultraclean environment, and use the CASPOL to discriminate between different aerosols, water and ice particles. In this paper, optical property measurements of mixed phase clouds and viscous Secondary Organic Aerosol (SOA) are presented. We report observations of significant liquid – viscous SOA particle polarisation transitions under dry conditions using CASPOL. Cluster analysis techniques were subsequently used to classify different types of particles according to their polarisation ratios during phase transition. A classification map is presented for water droplets, organic aerosol (e.g., SOA and oxalic acid), crystalline substances such as ammonium sulphate, and volcanic ash. Finally, we discuss the benefits and limitations of this classi- fication approach for atmospherically relevant concentration and mixtures with respect to the CLOUD 8–9 campaigns and its potential contribution to Tropical Troposphere Layer (TTL) analysis.
Cloud microphysical processes involving the ice phase in tropospheric clouds are among the major uncertainties in cloud formation, weather, and general circulation models. The detection of aerosol particles, liquid droplets, and ice crystals, especially in the small cloud particle-size range below 50 μm, remains challenging in mixed phase, often unstable environments. The Cloud Aerosol Spectrometer with Polarization (CASPOL) is an airborne instrument that has the ability to detect such small cloud particles and measure the variability in polarization state of their backscattered light. Here we operate the versatile Cosmics Leaving OUtdoor Droplets (CLOUD) chamber facility at the European Organization for Nuclear Research (CERN) to produce controlled mixed phase and other clouds by adiabatic expansions in an ultraclean environment, and use the CASPOL to discriminate between different aerosols, water, and ice particles. In this paper, optical property measurements of mixed-phase clouds and viscous secondary organic aerosol (SOA) are presented. We report observations of significant liquid–viscous SOA particle polarization transitions under dry conditions using CASPOL. Cluster analysis techniques were subsequently used to classify different types of particles according to their polarization ratios during phase transition. A classification map is presented for water droplets, organic aerosol (e.g., SOA and oxalic acid), crystalline substances such as ammonium sulfate, and volcanic ash. Finally, we discuss the benefits and limitations of this classification approach for atmospherically relevant concentrations and mixtures with respect to the CLOUD 8–9 campaigns and its potential contribution to tropical troposphere layer analysis.
The CARIBIC (Civil Aircraft for the Regular Investigation of the Atmosphere Based on an Instrument Container) passenger aircraft observatory performed in situ measurements at 10–12 km altitude in the South Asian summer monsoon anticyclone between June and September 2008. These measurements enable us to investigate this atmospheric region (which so far has mostly been observed from satellites) using the broad suite of trace gases and aerosol particles measured by CARIBIC. Elevated levels of a variety of atmospheric pollutants (e.g. carbon monoxide, total reactive nitrogen oxides, aerosol particles, and several volatile organic compounds) were recorded. The measurements provide detailed information about the chemical composition of air in different parts of the monsoon anticyclone, particularly of ozone precursors. While covering a range of 3500 km inside the monsoon anticyclone, CARIBIC observations show remarkable consistency, i.e. with distinct latitudinal patterns of trace gases during the entire monsoon period.
Using the CARIBIC trace gas and aerosol particle measurements in combination with the Lagrangian particle dispersion model FLEXPART, we investigated the characteristics of monsoon outflow and the chemical evolution of air masses during transport. The trajectory calculations indicate that these air masses originated mainly from South Asia and mainland Southeast Asia. Estimated photochemical ages of the air were found to agree well with transport times from a source region east of 90–95° E. The photochemical ages of the air in the southern part of the monsoon anticyclone were systematically younger (less than 7 days) and the air masses were mostly in an ozone-forming chemical mode. In its northern part the air masses were older (up to 13 days) and had unclear ozone formation or destruction potential. Based on analysis of forward trajectories, several receptor regions were identified. In addition to predominantly westward transport, we found evidence for efficient transport (within 10 days) to the Pacific and North America, particularly during June and September, and also of cross-tropopause exchange, which was strongest during June and July. Westward transport to Africa and further to the Mediterranean was the main pathway during July.
The CARIBIC (Civil Aircraft for the Regular Investigation of the Atmosphere Based on an Instrument Container) passenger aircraft observatory performed in situ measurements at 10–12 km altitude in the South Asian summer monsoon anticyclone between June and September 2008. These measurements enable us to investigate this atmospheric region, which so far has mostly been observed from satellites, using the broad suite of trace gases and aerosols measured by CARIBIC. Elevated levels of a range of atmospheric pollutants were recorded e.g. carbon monoxide, total reactive nitrogen oxides, aerosol particles and several volatile organic compounds. The measurements provide detailed information about the chemical composition of air in different parts of the monsoon anticyclone, particularly of ozone precursors. While covering a range of 3500 km inside the monsoon anticyclone, CARIBIC observations show remarkable consistency, i.e. with regular latitudinal patterns of trace gases during the entire monsoon period. Trajectory calculations indicate that these air masses originated mainly from South Asia and Mainland Southeast Asia.
Using the CARIBIC trace gas and aerosol measurements in combination with the Lagrangian particle dispersion model FLEXPART we investigated the characteristics of monsoon outflow and the chemical evolution of air masses during transport. Estimated photochemical ages of the air were found to agree well with transport times from a source region east of 95 ° E. The photochemical ages of the air in the southern part of the monsoon anticyclone were consistently younger (less than 7 days) and the air masses mostly in an ozone forming chemical regime. In its northern part the air masses were older (up to 13 days) and had unclear ozone formation or destruction potential. Based on analysis of forward trajectories several receptor regions were identified. In addition to predominantly westward transport, we found evidence for efficient transport (within 10 days) to the Pacific and North America, particularly during June and September, and also of cross-tropopause exchange, which was strongest during June and July. Westward transport to Africa and further to the Mediterranean was the main pathway during July.
The first concerted multi-model intercomparison of halogenated very short-lived substances (VSLS) has been performed, within the framework of the ongoing Atmospheric Tracer Transport Model Intercomparison Project (TransCom). Eleven global models or model variants participated, simulating the major natural bromine VSLS, bromoform (CHBr3) and dibromomethane (CH2Br2), over a 20-year period (1993-2012). The overarching goal of TransCom-VSLS was to provide a reconciled model estimate of the stratospheric source gas injection (SGI) of bromine from these gases, to constrain the current measurement-derived range, and to investigate inter-model differences
due to emissions and transport processes. Models ran with standardised idealised chemistry, to isolate differences due to transport, and we investigated the sensitivity of results to a range of VSLS emission inventories. Models were tested in their ability to reproduce the observed seasonal and spatial distribution of VSLS at the surface, using measurements from NOAA’s long-term global monitoring network, and in the tropical troposphere, using recent aircraft measurements - including high altitude observations from the NASA Global Hawk platform.
The models generally capture the seasonal cycle of surface CHBr3 and CH2Br2 well, with a strong model measurement correlation (r ≥0.7) and a low sensitivity to the choice of emission inventory, at most sites. In a given model, the absolute model-measurement agreement is highly sensitive to the choice of emissions and inter-model differences are also apparent, even when using the same inventory, highlighting the challenges faced in evaluating such inventories at the global scale. Across the ensemble, most consistency is found within the tropics where most of the models (8 out of 11) achieve optimal agreement to surface CHBr3 observations using the lowest of the three CHBr3 emission inventories tested (similarly, 8 out of 11 models for CH2Br2). In general, the models are able to reproduce well observations of CHBr3 and CH2Br2 obtained in the tropical tropopause layer (TTL) at various locations throughout the Pacific. Zonal variability in VSLS loading in the TTL is generally consistent among models, with CHBr3 (and to a lesser extent CH2Br2) most elevated over the tropical West Pacific during boreal winter. The models also indicate the Asian Monsoon during boreal summer to be an important pathway for VSLS reaching the stratosphere, though the strength of this signal varies considerably among models.
We derive an ensemble climatological mean estimate of the stratospheric bromine SGI from CHBr3 and CH2Br2 of 2.0 (1.2-2.5) ppt, ∼57% larger than the best estimate from the most re- cent World Meteorological Organization (WMO) Ozone Assessment Report. We find no evidence for a long-term, transport-driven trend in the stratospheric SGI of bromine over the simulation period. However, transport-driven inter-annual variability in the annual mean bromine SGI is of the order of a ±5%, with SGI exhibiting a strong positive correlation with ENSO in the East Pacific
Given an Abelian semi-group (A, +), an A-valued curvature measure is a valuation with values in A-valued measures. If A = R, complete classifications of Hausdorff-continuous translation-invariant SO(n)-invariant valuations and curvature measures were obtained by Hadwiger and Schneider, respectively. More recently, characterisation results have been achieved for curvature measures with values in A = Sym^p R^n and A = Sym^2 Λ^q R^n for p, q ≥ 1 with varying assumptions as for their invariance properties.
In the present work, we classify all smooth translation-invariant SO(n)-covariant curvature measures with values in any SO(n)-representation in terms of certain differential forms on the sphere bundle S R^n and describe their behaviour under the globalisation map. The latter result also yields a similar classification of all continuous SO(n)-module-valued SO(n)-covariant valuations. Furthermore, a decomposition of the space of smooth translation-
invariant scalar-valued curvature measures as an SO(n)-module is obtained. As a corollary, we construct explicit bases of continuous translation-invariant scalar-valued valuations and smooth translation-invariant scalar-valued curvature measures.
Xenia von Sankt-Petersburg (Ksenija Peterburgskaja) ist eine der bedeutendsten weiblichen Heiligen in der gesamten Orthodoxie. Ihr ungewöhnliches Leben entfaltete sich im 18. Jh. in der damaligen russischen Hauptstadt Sankt-Petersburg, zu deren heiligen Patronin sie später erwählt wurde. Doch erst in den vierziger Jahre des 19. Jahrhunderts wurden die ersten Zeugnisse über ihren Lebensweg und ihr religiöses Wirken schriftlich festgehalten. Um das Jahr 1912 entstand schliesslich eine Heiligenvita Xenias; sie wurde auf Grundlage bestehender Textfragmente und dem überlieferter Erzählungen aufgezeichnet. Im Jahr 1978 wurde Xenia zunächst von der Russisch-Orthodoxen Kirche im Ausland und dann im Jahr 1988 von dem Heiligen Synod (pomestnyj sobor) der Russisch-Orthodoxen Kirche des Moskauer Patriarchats offiziell heilig gesprochen.
Die Kanonisierung bestätigte aber nur eine seit fast zweihundert Jahren bestehende Volksverehrung. Ihrem hagiographischen Typus nach wurde Xenia als jurodivaja kategorisiert. Dieses russische Wort bedeutet in etwa eine Selige, ein Tolle, eine Wahnsinnige; sinngemäss eine heilige Närrin, die um Christi Willen vor der Augen der Öffentlichkeit einen Irrgang vorspielt, bewusst ein provokatives als deviant geltendes Verhalten an den Tag legt und sich dadurch den geltenden gesellschaftlichen Konventionen radikal verweigert.
The first concerted multi-model intercomparison of halogenated very short-lived substances (VSLS) has been performed, within the framework of the ongoing Atmospheric Tracer Transport Model Intercomparison Project (TransCom). Eleven global models or model variants participated (nine chemical transport models and two chemistry–climate models) by simulating the major natural bromine VSLS, bromoform (CHBr3) and dibromomethane (CH2Br2), over a 20-year period (1993–2012). Except for three model simulations, all others were driven offline by (or nudged to) reanalysed meteorology. The overarching goal of TransCom-VSLS was to provide a reconciled model estimate of the stratospheric source gas injection (SGI) of bromine from these gases, to constrain the current measurement-derived range, and to investigate inter-model differences due to emissions and transport processes. Models ran with standardised idealised chemistry, to isolate differences due to transport, and we investigated the sensitivity of results to a range of VSLS emission inventories. Models were tested in their ability to reproduce the observed seasonal and spatial distribution of VSLS at the surface, using measurements from NOAA's long-term global monitoring network, and in the tropical troposphere, using recent aircraft measurements – including high-altitude observations from the NASA Global Hawk platform.
The models generally capture the observed seasonal cycle of surface CHBr3 and CH2Br2 well, with a strong model–measurement correlation (r ≥ 0.7) at most sites. In a given model, the absolute model–measurement agreement at the surface is highly sensitive to the choice of emissions. Large inter-model differences are apparent when using the same emission inventory, highlighting the challenges faced in evaluating such inventories at the global scale. Across the ensemble, most consistency is found within the tropics where most of the models (8 out of 11) achieve best agreement to surface CHBr3 observations using the lowest of the three CHBr3 emission inventories tested (similarly, 8 out of 11 models for CH2Br2). In general, the models reproduce observations of CHBr3 and CH2Br2 obtained in the tropical tropopause layer (TTL) at various locations throughout the Pacific well. Zonal variability in VSLS loading in the TTL is generally consistent among models, with CHBr3 (and to a lesser extent CH2Br2) most elevated over the tropical western Pacific during boreal winter. The models also indicate the Asian monsoon during boreal summer to be an important pathway for VSLS reaching the stratosphere, though the strength of this signal varies considerably among models.
We derive an ensemble climatological mean estimate of the stratospheric bromine SGI from CHBr3 and CH2Br2 of 2.0 (1.2–2.5) ppt, ∼ 57 % larger than the best estimate from the most recent World Meteorological Organization (WMO) Ozone Assessment Report. We find no evidence for a long-term, transport-driven trend in the stratospheric SGI of bromine over the simulation period. The transport-driven interannual variability in the annual mean bromine SGI is of the order of ±5 %, with SGI exhibiting a strong positive correlation with the El Niño–Southern Oscillation (ENSO) in the eastern Pacific. Overall, our results do not show systematic differences between models specific to the choice of reanalysis meteorology, rather clear differences are seen related to differences in the implementation of transport processes in the models.
Interleukin (IL)-22 is a STAT3-activating cytokine displaying characteristic AU-rich elements (ARE) in the 3'-untranslated region (3'-UTR) of its mRNA. This architecture suggests gene regulation by modulation of mRNA stability. Since related cytokines undergo post-transcriptional regulation by ARE-binding tristetraprolin (TTP), the role of this destabilizing protein in IL-22 production was investigated. Herein, we demonstrate that TTP-deficient mice display augmented serum IL-22. Likewise, IL-22 mRNA was enhanced in TTP-deficient splenocytes and isolated primary T cells. A pivotal role for TTP is underscored by an extended IL-22 mRNA half-life detectable in TTP-deficient T cells. Luciferase-reporter assays performed in human Jurkat T cells proved the destabilizing potential of the human IL-22-3'-UTR. Furthermore, overexpression of TTP in HEK293 cells substantially decreased luciferase activity directed by the IL-22-3'-UTR. Transcript destabilization by TTP was nullified upon cellular activation by TPA/A23187, an effect dependent on MEK1/2 activity. Accordingly, IL-22 mRNA half-life as determined in TPA/A23187-stimulated Jurkat T cells decreased under the influence of the MEK1/2 inhibitor U0126. Altogether, data indicate that TTP directly controls IL-22 production, a process counteracted by MEK1/2. The TTP-dependent regulatory pathway described herein likely contributes to the role of IL-22 in inflammation and cancer and may evolve as novel target for pharmacological IL-22 modulation.
NLP4CMC III : 3rd workshop on natural language processing for computer-mediated communication
(2016)
The present paper reports the first results of the compilation and annotation of a blog corpus for German. The main aim of the project is the representation of the blog discourse structure and relations between its elements (blog posts, comments) and participants (bloggers, commentators). The data included in the corpus were manually collected from the scientific blog portal SciLogs. The feature catalogue for the corpus annotation includes three types of information which is directly or indirectly provided in the blog or can be construed by means of statistical analysis or computational tools. At this point, only directly available information (e.g., title of the blog post, name of the blogger etc.) has been annotated. We believe, our blog corpus can be of interest for the general study of blog structure or related research questions as well as for the development of NLP methods and techniques (e.g. for authorship detection).
Already today modern driver assistance systems contribute more and more to make individual mobility in road traffic safer and more comfortable. For this purpose, modern vehicles are equipped with a multitude of sensors and actuators which perceive, interpret and react to the environment of the vehicle. In order to reach the next set of goals along this path, for example to be able to assist the driver in increasingly complex situations or to reach a higher degree of autonomy of driver assistance systems, a detailed understanding of the vehicle environment and especially of other moving traffic participants is necessary.
It is known that motion information plays a key role for human object recognition [Spelke, 1990]. However, full 3D motion information is mostly not taken into account for Stereo Vision-based object segmentation in literature. In this thesis, novel approaches for motion-based object segmentation of stereo image sequences are proposed from which a generic environmental model is derived that contributes to a more precise analysis and understanding of the respective traffic scene. The aim of the environmental model is to yield a minimal scene description in terms of a few moving objects and stationary background such as houses, crash barriers or parking vehicles. A minimal scene description aggregates as much information as possible and it is characterized by its stability, precision and efficiency.
Instead of dense stereo and optical flow information, the proposed object segmentation builds on the so-called Stixel World, an efficient superpixel-like representation of space-time stereo data. As it turns out this step substantially increases stability of the segmentation and it reduces the computational time by several orders of magnitude, thus enabling real-time automotive use in the first place. Besides the efficient, real-time capable optimization, the object segmentation has to be able to cope with significant noise which is due to the measurement principle of the used stereo camera system. For that reason, in order to obtain an optimal solution under the given extreme conditions, the segmentation task is formulated as a Bayesian optimization problem which allows to incorporate regularizing prior knowledge and redundancies into the object segmentation.
Object segmentation as it is discussed here means unsupervised segmentation since typically the number of objects in the scene and their individual object parameters are not known in advance. This information has to be estimated from the input data as well.
For inference, two approaches with their individual pros and cons are proposed, evaluated and compared. The first approach is based on dynamic programming. The key advantage of this approach is the possibility to take into account non-local priors such as shape or object size information which is impossible or which is prohibitively expensive with more local, conventional graph optimization approaches such as graphcut or belief propagation.
In the first instance, the Dynamic Programming approach is limited to one-dimensional data structures, in this case to the first Stixel row. A possible extension to capture multiple Stixel rows is discussed at the end of this thesis.
Further novel contributions include a special outlier concept to handle gross stereo errors associated with so-called stereo tear-off edges. Additionally, object-object interactions are taken into account by explicitly modeling object occlusions. These extensions prove to be dramatic improvements in practice.
This first approach is compared with a second approach that is based on an alternating optimization of the Stixel segmentation and of the relevant object parameters in an expectation maximization (EM) sense. The labeling step is performed by means of the _−expansion graphcut algorithm, the parameter estimation step is done via one-dimensional sampling and multidimensional gradient descent. By using the Stixel World and due to an efficient implementation, one step of the optimization only takes about one millisecond on a standard single CPU core. To the knowledge of the author, at the time of development there was no faster global optimization in a demonstrator car.
For both approaches, various testing scenarios have been carefully selected and allow to examine the proposed methods thoroughly under different real-world conditions with limited groundtruth at hand. As an additional innovative application, the first approach was successfully implemented in a demonstrator car that drove the so-called Bertha Benz Memorial Route from Mannheim to Pforzheim autonomously in real traffic.
At the end of this thesis, the limits of the proposed systems are discussed and a prospect on possible future work is given.
BACKGROUND: Microvascular ischemia is one of the hallmarks of hypertrophic cardiomyopathy (HCM) and has been associated with poor outcome. However, myocardial fibrosis, seen on cardiovascular magnetic resonance (CMR) as late gadolinium enhancement (LGE), can be responsible for rest perfusion defects in up to 30% of patients with HCM, potentially leading to an overestimation of the ischemic burden. We investigated the effect of left ventricle (LV) scar on the total LV ischemic burden using novel high-resolution perfusion analysis techniques in conjunction with LGE quantification.
METHODS: 30 patients with HCM and unobstructed epicardial coronary arteries underwent CMR with Fermi constrained quantitative perfusion analysis on segmental and high-resolution data. The latter were corrected for the presence of fibrosis on a pixel-by-pixel basis.
RESULTS: High-resolution quantification proved more sensitive for the detection of microvascular ischemia in comparison to segmental analysis. Areas of LGE were associated with significant reduction of myocardial perfusion reserve (MPR) leading to an overestimation of the total ischemic burden on non-corrected perfusion maps. Using a threshold MPR of 1.5, the presence of LGE caused an overestimation of the ischemic burden of 28%. The ischemic burden was more severe in patients with fibrosis, also after correction of the perfusion maps, in keeping with more severe disease in this subgroup.
CONCLUSIONS: LGE is an important confounder in the assessment of the ischemic burden in patients with HCM. High-resolution quantitative analysis with LGE correction enables the independent evaluation of microvascular ischemia and fibrosis and should be used when evaluating patients with HCM.
Stifter-Gänge
(2007)
Ist 'das Ding' Stifters liebstes Substantiv, so darf 'gehen' als sein bevorzugtes Verb gelten. In der Erzählung 'Der Waldgänger' sieht sich etwa der an einem lebensweltlichen und geographischen "Scheidepunkte" innehaltende Wanderer von einer Landschaft umgeben, in der die Dinge buchstäblich ihren Gang gehen:
'Ganz oben, wo das Thal mit noch geringer Tiefe anfängt, begann auch ein winziges Wasserfädlein, neben dem Wanderer abwärts zu gehen. Es ging in dem Rinnsale neben dem Wege unhörbar und nur glizzernd vorwärts, bis es durch die Menge des durch die Höhen sickernden Wassers gestärkt vor ihm plaudernd und rauschend einher hüpfte, als wolle es ihm den Weg durch die Thalmündung hinaus zeigen [...]. Sie gingen an manchem Waldabhange, an mancher schattigen Stelle vorbei [...], sie gingen an manchen zerstreuten Häuschen, an mancher Mühle, an mancher auf einem tiefgelegenen Wiesenflecken weidenden Kuh vorüber, bis endlich nach einigen Stunden Wanderns [...] die hingebreitete große Ebene begann. Der Bach ging breit und wallend links gegen die Felder und Bäume [...]. (WG, 98f)'
Dem Gang der Dinge untersteht der Lauf der Welt. Diese Identität von Naturvorgängen und Lebensläufen immer neu, allen Irrwegen und Katastrophen, allen Sprüngen und Brüchen zum Trotz, unter Beweis stellen zu wollen, tritt Stifters Autorschaft an. Trauma und Trost seines Universums liegen beschlossen in dem fast stereotyp wiederkehrenden Satz: "Und so ging es immer fort."
Does an increase in competition increase or decrease bank stability? I exploit how the state-specific process of interstate banking deregulation lowered barriers to entry into urban banking markets and find that greater competition significantly increases bank stability. This result is robust to the inclusion of additional fixed effects and other influences, such as merger and acquisitions or diversification. Moreover, I find that greater competition reduces banks' nonperforming loans and increases bank profitability. These findings suggest that competition increases stability as it improves bank profitability and asset quality.
Returns to experience for U.S. workers have changed over the post-war period. This paper argues that a simple model goes a long way towards replicating these changes. The model features three well-known ingredients: (i) an aggregate production function with constant skill-biased technical change; (ii) cohort qualities that vary with average years of schooling; and crucially (iii) time-invariant age-efficiency profiles. The model quantitatively accounts for changes in longitudinal and cross-sectional returns to experience, as well as the differential evolution of the college wage premium for young and old workers.
We reconsider the role for human capital in accounting for cross-country income differences. Our contribution is to bring to bear new data on the pre- and post- migration labor market experiences of immigrants to the U.S. Immigrants from poor countries experience wage gains that are only 40 percent of the GDP per worker gap, which implies that “country" accounts for 40 percent of income differences, while human capital accounts for 60 percent. Our approach handles selection by comparing the wage of the same individual in two different countries. We also provide evidence on and a correction for skill transfer.
We examine the impact of house prices on labour supply decisions using UK micro data. We combine household survey data with local level house price measures and controls for local labour demand. Our micro data also allows us to control for individual level income expectations. We find significant house price effects on labour supply, consistent with leisure being a normal good. Labour supply responses to house prices are concentrated among young married female owners and older owners. This finding suggests house prices affect the decisions of marginal workers in the economy. Our estimates imply house prices are economically important for the participation decisions for these workers.
Although Walter Benjamin was never timid when it came to writing, one practice he consistently avoided was that of creating neologisms. It is therefore with all the more reluctance that I find myself compelled to resort to something similar, in order to sum up a motif that has imposed itself over the years in my reading of Benjamin. What is involved is, to be sure, not exactly a neologism, since it does not involve the creation of a new word, but rather the highlighting of a word-part, a suffix (eine Nachsilbe). In English, to be sure, this suffix, when spoken, is indistinguishable from a word: what distinguishes it from a word is not audible, but only legible: a hyphen, marking a separation that is also a joining, a 'Bindestrich' that does not bind it to anything in particular and yet that requires it to be bound to something else. The suffix in question thus sounds deceptively familiar, since it coincides, audibly, with the word "abilities". However, unlike that word, its first letter - which purely by accident happens to be the first letter of the alphabet--is preceded by a dash. When written in isolation, this gives it a somewhat bizarre appearance, to be sure, since suffixes are not usually encountered separately from the words they modify. But this bizarre appearance pales when compared to its German 'original'. If the book of essays to be published in English under the title, "Benjamin’s -abilities," is ever translated into German - "back" into German I was tempted to write, since German here is of course the language in which Benjamin wrote and in which I generally read him - then its title, were it to be entirely faithful to the English, would indeed have to involve the creation of a neologism. For translated back into German, the German title would require its readers to "read, what was never written", namely: "Benjamins -barkeiten" (written, "Bindestrich- b--kleingeschrieben").
En tentant de regarder une image singulière avec quelques mots de Walter Benjamin, je voudrais, non pas me livrer à un exercice de commentaire, de glose ou de déchiffrement, mais, plus modestement, faire acte de reconnaissance, porter témoignage d’une experience de l’image, d’une 'poétique de l’image'. Walter Benjamin, l’un des penseurs qui a le plus radicalement bouleversé - réinventé - la notion de lisibilité (Lesbarkeit), est aussi l’un des penseurs au contact duquel l’histoire de l’art se trouve bouleversée dans son rapport même à la visibilité (Sichtbarkeit) et à la temporalité des images. Il ne s’agit pas seulement de rendre hommage à celui qui, mieux que quiconque, aura théorisé le rôle de la reproductibilité, taconté l’histoire de "l’art en tant que photographie" ou décrit le "déclin de l’aura". Il s’agit de travailler avec sa façon de mettre le temps au coeur de toute question d’image, et de faire de l’image - à commencer par la fameuse "image dialectique" - l’opérateur central de toute historicité. Le meilleur hommage, la meilleure justice que l’on puisse rendre à quelque chose, dit Benjamin - en parlant des "guenilles", des "rebuts" de l’histoire -, c’est de l’utiliser. Je vais tâcher de suivre cette leçon en vous présentant un objet de travail et en essayant de restituer la 'valeur d’usage' d’un ou de deux textes de Benjamin pour tenter de savoir, tout simplement, 'comment regarder une image'.
We study money creation and destruction in today’s monetary architecture and examine the impact of monetary policy and capital regulation in a general equilibrium setting. There are two types of money created and destructed: bank deposits, when banks grant loans to firms or to other banks and central bank money, when the central bank grants loans to private banks. We show that equilibria yield the first-best level of money creation and lending when prices are flexible, regardless of the monetary policy or capital regulation. When prices are rigid, we identify the circumstances in which money creation is excessive or breaks down and the ones in which an adequate combination of monetary policy and capital regulation can restore efficiency.
The dramatic shift from traditional pension plans to participant-directed 401(k) plans has increased the decision-making responsibility of individual investors for their own retirement planning. With this shift comes increasing evidence that investors are making poor decisions in choosing how much to save for retirement and in selecting among their investment options. Studies question the value of efforts to improve these decisions through regulatory reforms or investor education.
This article posits that deficiencies in workplace retirement savings cannot be adequately addressed until the reasons for poor investment decisions are better understood. We report the results of an exploratory study that asked subjects to complete a simulated retirement investment task and collected information about their financial knowledge and preferences. The study enabled us to measure financial literacy and evaluate its relationship to retirement investment decision-making. In line with existing research, we found a strong relationship between financial literacy and successful retirement investing. Our results suggest, however, that the relevant understanding in this context is not about math so much as it is a basic knowledge of the relative costs and benefits of the major investment categories. Finally, we present results suggesting that financial literacy is separate from investment preferences — specifically, that tolerance for risk is a separate and highly predictive variable in estimating retirement planning success.
Our research suggests that individual employees are likely to lack the skills necessary to support the current regulatory model of participant-directed retirement investing. The structure and regulation of retirement plans ought to take this fact seriously. We explore the potential for investor education and professional advice, respectively, to overcome the limitations of individualized choice.
Directors have traditionally been elected by a plurality of the votes cast. This means that in uncontested elections, a candidate who receives even a single vote is elected. Proponents of “shareholder democracy” have advocated a shift to a majority voting rule in which a candidate must receive a majority of the votes cast to be elected. Over the past decade, they have been successful, and the shift to majority voting has been one of the most popular and successful governance reforms.
Yet critics are skeptical as to whether majority voting improves board accountability. Tellingly, directors of companies with majority voting rarely fail to receive majority approval – even more rarely than directors of companies with plurality voting. Even when such directors fail to receive majority approval, they are unlikely to be forced to leave the board. This poses a puzzle: why do firms switch to majority voting and what effect does the switch have, if any, on director behavior?
We empirically examine the adoption and impact of a majority voting rule using a sample of uncontested director elections from 2007 to 2013. We test and find partial support for four hypotheses that could explain why directors of majority voting firms so rarely fail to receive majority support: selection; deterrence/accountability; electioneering by firms; and restraint by shareholders.
Our results further suggest that the reasons for and effects of adopting majority voting may differ between early and later adopters. We find that early adopters of majority voting were more shareholder-responsive than other firms even before they adopted majority voting. These firms seem to have adopted majority voting voluntarily, and the adoption of majority voting has made little difference in their responsiveness to shareholders responsiveness going forward. By contrast, for late adopters, we find no evidence that they were more shareholder-responsive than other firms before they adopted majority voting, but strong evidence that they became more responsive after adopting majority voting.
Differences between early and late adopters can have important implications for understanding the spread of corporate governance reforms and evaluating their effects on firms. Reform advocates, rather than targeting the firms that, by their measures, are most in need of reform, instead seem to have targeted the firms that are already most responsive. They may then have used the widespread adoption of majority voting to create pressure on the nonadopting firms. Empirical studies of the effects of governance changes thus need to be sensitive to the possibility that early adopters and late adopters of reforms differ from each other and that the reforms may have different effects on these two groups of firms.
The article discusses the methodology adopted for a cross-linguistic synchronic and diachronic corpus study on indefinites. The study covered five indefinite expressions, each in a different language. The main goal of the study was to verify the distribution of these indefinites synchronically and to attest their historical development. The methodology we used is a form of functional labeling which combines both context (syntax) and meaning (semantics) using as a starting point Haspelmath’s (1997) functional map. In the article we identify Haspelmath’s functions with logico-semantic interpretations and propose a binary branching decision tree assigning each instance of an indefinite exactly one function in the map.
Event studies have become increasingly important in securities fraud litigation after the Supreme Court’s decision in Halliburton II. Litigants have used event study methodology, which empirically analyzes the relationship between the disclosure of corporate information and the issuer’s stock price, to provide evidence in the evaluation of key elements of federal securities fraud, including materiality, reliance, causation, and damages. As the use of event studies grows and they increasingly serve a gatekeeping function in determining whether litigation will proceed beyond a preliminary stage, it will be critical for courts to use them correctly.
This Article explores an array of considerations related to the use of event studies in securities fraud litigation. It starts by describing the basic function of the event study: to determine whether a highly unusual price movement has occurred and the traditional statistical approach to making that determination. The Article goes on to identify special features of securities fraud litigation that distinguish litigation from the scholarly context in which event studies were developed. The Article highlights the fact that the standard approach can lead to the wrong conclusion and describes the adjustments necessary to address the litigation context. We use the example of six dates in the Halliburton litigation to illustrate these points.
Finally, the Article highlights the limitations of event studies – what they can and cannot prove – and explains how those limitations relate to the legal issues for which they are introduced. These limitations bear upon important normative questions about the role event studies should play in securities fraud litigation.
Cells perform a wide range of functions such as signalling, transportation, immunoprotection and metabolism. Unravelling the molecular mechanism behind those processes will provide a platform for more targeted and rational drug design. This is achieved by discerning the structural and functional aspects of the biological macromolecules involved. This thesis discusses about the biophysical characterization of protein structures and the biological importance of protein dynamics. Membrane receptors and enzymes which are ubiquitously present in our biological systems and regulate wide variety of functions are excellent choice for such study. From a pharmaceutical point of view, receptor and enzymes are exceptionally important drug targets as they represent the major share (receptor, 30% and enzymes, 47%) of all marketed drugs. Therefore, apart from biological insights, the detailed study of receptors and enzymes will provide the basis for new pharmaceutical applications. Most information about receptor activation and enzyme activity come from the structural and functional analysis of target members of the above mentioned systems.
In “Chapter 1 – General Introduction” the readers are introduced to the world of proteins with special focus on G-protein coupled receptors (GPCRs) and methyltransferases. The first part of this chapter discusses about GPCRs with emphasis on their classification, structural features and functions. GPCRs are the most abundant membrane receptors present in mammalian cells, accounting for almost 15% of all membrane proteins. The GPCR superfamily consists of ~800 members and can be subdivided into six classes (A-F). Class A containing rhodopsin, peptide hormones, olfactory GPCRs, is the most abundant with a large share of 85% of GPCR protein family. GPCRs share a common architecture of 7 transmembrane a-helices, with different ligand binding sites. Although a variety of ligands ranging from subatomic particles (a photon) to large proteins can activate a GPCR, their mechanism of signal transduction is almost similar. There are two major signal transduction pathways identified for GPCRs: the cAMP pathway and the phosphatidylinositol pathway. The therapeutic relevance of GPCRs has also been pointed out here since a large share (30%) of modern marketed drugs target GPCRs.
In the second part of this chapter, the structural and functional characterizations of methyltransferases (MTs) are discussed in detail. Several important biological processes in cells e.g. drug metabolism, gene transcription, epigenetic regulations are modulated by methylation of targets ranging from small biomolecules to large proteins. MTs are the proteins which catalyze this methylation reaction and transfer the methyl group to an acceptor molecule through SN2 like nucleophilic substitution reaction. The MTs can be classified on the basis of the substrate atoms they methylate: O (54% of all MTs), N (23%), C (18%), S (3%) and other acceptors (such as halides; 2%). They can also be categorized into five different classes (Class I-V) depending upon distinctive structural features facilitating substrate binding or catalytic activity. Rossmann fold and SET (acronym acquired from the Drosophila Su(var)3-9 and 'Enhancer of zeste' proteins) domain are the two characteristic structural motifs commonly found in MTs. Similar to GPCRs, MTs dysfunction has been shown to be involved in various diseases including neuropsychiatric diseases and cancer. Therefore they are also interesting targets for drug development. The final part of this chapter discusses the importance of structural biology in gathering information related to structure and conformational dynamics of proteins. The two prominent biophysical techniques used in structural biology, X-ray crystallography and NMR, are discussed with focus on their advantages and limitation. The importance of NMR spectroscopic techniques to investigate different dynamic processes of protein at atomic resolution under physiological conditions is also discussed. Real time NMR spectroscopy required for the analysis of slow protein dynamic processes (protein folding, enzyme catalysis, domain rearrangement) has been explained in detail.
The second part of the thesis (Chapters 3-4), which is the cumulative part, comprises the original publications grouped into 2 chapters according to their topic:
• NMR-spectroscopic characterization of the transiently populated photointermediates of bovine rhodopsin and it’s interaction with arrestin (Chapter 3)
• Structural and biophysical characterization of PaMTH1, a putative SAM dependent O-methyltransferase from filamentous fungi Podospora anserina (Chapter 4)
Each chapter is initiated by a detailed introduction to the topic, providing the framework for the following papers. The personal contribution of this thesis’ author to each publication is stated in the introduction to the respective article.
In dieser Arbeit wurden die Strukturen von drei Membranproteinen mittels Einzelpartikel-Kryo‑Elektronenmikroskopie (Kryo‑EM) gelöst. Bei den Membranproteinen handelt es sich um den humanen TRP-Kanal Polycystin‑2, den sekundär-aktiven Transporter BetP aus Corynebacterium glutamicum und den Rotor-Ring der N‑Typ ATPase aus Burkholderia pseudomallei.
Kanäle sind Membranproteine, die Ionen durch eine Pore über die Membran diffundieren lassen. Durch einen präzisen, kanalabhängigen Regulationsmechanismus wird die Pore nur bei Bedarf geöffnet. TRP (transient receptor potential) Kanäle sind anhand von DNA-Sequenzvergleichen identifiziert worden und kommen ausschließlich in Eukaryonten vor. In dieser Arbeit lag der Fokus auf der Strukturbestimmung des humanen TRP Kanals Polycystin‑2 (PC‑2). PC‑2 wurde in einer Studie entdeckt, in der Patienten mit der autosomal dominanten Erbkrankheit „polyzystische Nierenerkrankung“ untersucht wurden. Patienten mit dieser Krankheit tragen eine Mutation in einem der beiden Gene PKD1 oder PKD2, welche für die Proteine Polycystin‑1 und ‑2 kodieren. In dieser Arbeit wurden verschiedene Deletionsmutanten von PC‑2 hergestellt und in das Genom menschlicher HEK293 GnTI‑ Zellen inseriert. Die Zellen, die PC‑2 bzw. die Deletionskonstrukte am stärksten synthetisierten, wurden isoliert und für die rekombinante Proteinherstellung verwendet. Die Expression von PC‑2 führte zu der Entstehung von kristalloidem endoplasmatischem Retikulum. Mutationsstudien in dieser Arbeit zeigen, dass diese morphologische Veränderung durch die Akkumulation von Membranproteinen, die mit sich selbst interagieren, begünstigt wird. Weiter ist es in dieser Arbeit gelungen, PC‑2 zu reinigen und die Struktur des Proteins mit Hilfe von Einzelpartikel Kryo-EM mit einer Auflösung von 4.6 Å zu bestimmen. Die Membrandomäne von PC‑2 ist sehr ähnlich zu den bekannten TRP Kanal Strukturen. Ein Vergleich der PC‑2 Struktur mit dem offenen und geschlossenen TRPV1 Kanal legt nahe, dass PC‑2 in seiner offenen Konformation gelöst wurde.
Der sekundär aktive Transporter BetP von C. glutamicum gehört zu der Familie der BCC- (betaine-carnitine-choline) Transporter und wird durch osmotischen Schock aktiviert. Nach seiner Aktivierung importiert BetP zwei Natriumionen und ein Glycinbetain Molekül. Durch die Akkumulierung von Glycinbetain in der Zelle steigt das osmotische Potential des Zytoplasmas, was den Wasserausstrom aus der Zelle stoppt. Viele Strukturen, die BetP in unterschiedlichen Stadien des Transportprozesses zeigen, konnten bereits mittels Röntgenkristallographie gelöst werden. Allerdings ist die N‑terminale Domäne für die Kristallisation entfernt worden und die C‑terminale Domäne, die komplett aufgelöst ist, ist an einem wichtigen Kristallkontakt beteiligt. Um strukturelle Informationen über die N‑ und C‑terminale Domäne ohne Kristallisationsartefakte zu erhalten, wurde in dieser Arbeit die Struktur von BetP mittels Einzelpartikel Kryo‑EM bestimmt. Die Struktur mit einer Auflösung von 6.8 Å zeigt BetP in einem zum Zytoplasma geöffneten Zustand. Der größte Unterschied zu allen Kristallstrukturen ist die Position der C‑terminalen α‑Helix, die um ~30° rotiert ist und dadurch deutlich enger am Protein zu liegen kommt. Da BetP in Abwesenheit von aktivierenden Stoffen analysiert wurde, wird vermutet, dass es sich bei der gelösten Struktur um den inaktiven Zustand von BetP handelt.
Rotierende ATPasen sind membrangebunden Enzymkomplexe, die bei der zellulären Energieumwandlung eine entscheidende Rolle einnehmen. Sie bestehen aus einem löslichen und einem membrangebundenen Teil. Während in dem löslichen Teil der zelluläre Energieträger Adenosintriphosphat (ATP) entweder synthetisiert oder hydrolysiert wird, baut der membrangebundene Teil entweder einen Ionengradienten auf oder nutzt die Energie eines existierenden Gradienten für die ATP Synthese. Ein wesentlicher Bestandteil des membrangebundenen Teils einer rotierenden ATPase ist der Rotor-Ring. Dieser transportiert Ionen über die Membran und rotiert dabei um seine eigene Achse. In dieser Arbeit wurde eine Studie fortgesetzt, die den Rotor-Ring der N‑Typ ATPase von B. pseudomallei mittels Kryo‑EM untersuchte und zeigte, dass der Rotor-Ring aus 17 identischen Untereinheiten aufgebaut ist. Damit hat die N‑Typ ATPase das größte Ionen-zu-ATP-Verhältnis aller bisher charakterisierten ATPasen. In dieser Arbeit wurde die c17 Stöchiometrie des N‑Typ ATPase Rotor-Rings bestätigt und die Struktur mittels Kryo‑EM bestimmt. Im besonderen Fokus lag dabei der Einfluss von Detergenzien auf die Strukturbestimmung. Es konnte gezeigt werden, dass die beiden Parameter Dichte und Mizellengröße der verwendeten Detergenzien ausschlaggebend für den Erfolg der Strukturbestimmung dieses sehr kleinen Membranproteins sind.
A three-dimensional gridded climatology of carbon monoxide (CO) has been developed by trajectory mapping of global MOZAIC-IAGOS in situ measurements from commercial aircraft data. CO measurements made during aircraft ascent and descent, comprising nearly 41 200 profiles at 148 airports worldwide from December 2001 to December 2012, are used. Forward and backward trajectories are calculated from meteorological reanalysis data in order to map the CO measurements to other locations and so to fill in the spatial domain. This domain-filling technique employs 15 800 000 calculated trajectories to map otherwise sparse MOZAIC-IAGOS data into a quasi-global field. The resulting trajectory-mapped CO data set is archived monthly from 2001 to 2012 on a grid of 5° longitude × 5° latitude × 1 km altitude, from the surface to 14 km altitude.
The mapping product has been carefully evaluated, firstly by comparing maps constructed using only forward trajectories and using only backward trajectories. The two methods show similar global CO distribution patterns. The magnitude of their differences is most commonly 10 % or less and found to be less than 30 % for almost all cases. Secondly, the method has been validated by comparing profiles for individual airports with those produced by the mapping method when data from that site are excluded. While there are larger differences below 2 km, the two methods agree very well between 2 and 10 km with the magnitude of biases within 20 %. Finally, the mapping product is compared with global MOZAIC-IAGOS cruise-level data, which were not included in the trajectory-mapped data set, and with independent data from the NOAA aircraft flask sampling program. The trajectory-mapped MOZAIC-IAGOS CO values show generally good agreement with both independent data sets.
Maps are also compared with version 6 data from the Measurements Of Pollution In The Troposphere (MOPITT) satellite instrument. Both data sets clearly show major regional CO sources such as biomass burning in Central and southern Africa and anthropogenic emissions in eastern China. While the maps show similar features and patterns, and relative biases are small in the lowermost troposphere, we find differences of ∼ 20 % in CO volume mixing ratios between 500 and 300 hPa. These upper-tropospheric biases are not related to the mapping procedure, as almost identical differences are found with the original in situ MOZAIC-IAGOS data. The total CO trajectory-mapped MOZAIC-IAGOS column is also higher than the MOPITT CO total column by 12–16 %.
The data set shows the seasonal CO cycle over different latitude bands and altitude ranges as well as long-term trends over different latitude bands. We observe a decline in CO over the northern hemispheric extratropics and the tropics consistent with that reported by previous studies using other data sources.
We anticipate use of the trajectory-mapped MOZAIC-IAGOS CO data set as an a priori climatology for satellite retrieval and for air quality model validation and initialization.
A three-dimensional gridded climatology of carbon monoxide (CO) has been developed by trajectory mapping of global MOZAIC-IAGOS in situ measurements from commercial aircraft data. CO measurements made during aircraft ascent and descent, comprising nearly 41 200 profiles at 148 airports worldwide from December 2001 to December 2012 are used. Forward and backward trajectories are calculated from meteorological reanalysis data in order to map the CO measurements to other locations, and so to fill in the spatial domain. This domain-filling technique employs 15 800 000 calculated trajectories to map otherwise sparse MOZAIC-IAGOS data into a quasi-global field. The resulting trajectory-mapped CO dataset is archived monthly from 2001–2012 on a grid of 5° longitude × 5° latitude × 1 km altitude, from the surface to 14 km altitude.
The mapping product has been carefully evaluated, by comparing maps constructed using only forward trajectories and using only backward trajectories. The two methods show similar global CO distribution patterns. The magnitude of their differences is most commonly 10 % or less, and found to be less than 30 % for almost all cases. The trajectory-mapped CO dataset has also been validated by comparison profiles for individual airports with those produced by the mapping method when data from that site are excluded. While there are larger differences below 2 km, the two methods agree very well between 2 and 10 km with the magnitude of biases within 20 %.
Maps are also compared with Version 6 data from the Measurements Of Pollution In The Troposphere (MOPITT) satellite instrument. While agreement is good in the lowermost troposphere, the MOPITT CO profile shows negative biases of ∼ 20 % between 500 and 300 hPa. These upper troposphere biases are not related to the
mapping procedure, as almost identical differences are found with the original in situ MOZAIC-IAGOS data. The total CO trajectory-mapped MOZAIC-IAGOS climatology column agrees with the MOPITT CO total column within ±5 %, which is consistent with previous reports.
The maps clearly show major regional CO sources such as biomass burning in the central and southern Africa and anthropogenic emissions in eastern China. The dataset shows the seasonal CO cycle over different latitude bands and altitude ranges that are representative of the regions as well as long-term trends over latitude bands. We observe a decline in CO over the Northern Hemisphere extratropics and the tropics consistent with that reported by previous studies.
Similar maps have been made using the concurrent O3 measurements by MOZAICIAGOS, as the global variation of O3–CO correlations can be a useful tool for the evaluation of ozone sources and transport in chemical transport models. We anticipate use of the trajectory-mapped MOZAIC-IAGOS CO dataset as an a priori climatology for satellite retrieval, and for air quality model validation and initialization.
The transport of air masses originating from the Asian monsoon anticyclone into the extratropical upper troposphere and lower stratosphere (Ex-UTLS) above potential temperatures Θ = 380K was identified during the HALO aircraft mission TACTS in August and September 2012. In-situ measurements of CO, O3 and N2O during TACTS Flight 2 on the 30 August 2012 show the irreversible mixing of aged with younger (originating from the troposphere) stratospheric air masses within the Ex-UTLS. Backward trajectories calculated with the trajetory module of the CLaMS model indicate that these tropospherically affected air masses originate from the Asian monsoon anticyclone. From the monsoon circulation region these air masses are quasi-isentropically transported above Θ = 380 K into the Ex-UTLS where they subsequently mix with stratospheric air masses. The overall trace gas distribution measured during TACTS shows that this transport pathway has a significant impact on the Ex-UTLS during boreal summer and autumn. This leads to an intensification of the tropospheric influence on the Ex-UTLS with ∆Θ > 30 K (relative to the tropopause) within three weeks during the TACTS mission. In the same time period a weakening of the tropospheric influence on the lowermost stratosphere (LMS) is determined. Therefore, the study shows that the transport of air masses originating from the Asian summer monsoon region within the lower stratosphere above Θ = 380K is of major importance for the change of the chemical composition of the Ex-UTLS from summer to autumn.
The transport of air masses originating from the Asian monsoon anticyclone into the extratropical upper troposphere and lower stratosphere (Ex-UTLS) above potential temperatures Θ = 380 K was identified during the HALO aircraft mission TACTS in August and September 2012. In situ measurements of CO, O3 and N2O during TACTS flight 2 on 30 August 2012 show the irreversible mixing of aged stratospheric air masses with younger (recently transported from the troposphere) ones within the Ex-UTLS. Backward trajectories calculated with the trajectory module of CLaMS indicate that these tropospherically affected air masses originate from the Asian monsoon anticyclone. These air masses are subsequently transported above potential temperatures Θ = 380 K from the monsoon circulation region into the Ex-UTLS, where they subsequently mix with stratospheric air masses. The overall trace gas distribution measured during TACTS shows that this transport pathway had affected the chemical composition of the Ex-UTLS during boreal summer and autumn 2012. This leads to an intensification of the tropospheric influence on the extratropical lower stratosphere with PV > 8 pvu within 3 weeks during the TACTS mission. During the same time period a weakening of the tropospheric influence on the lowermost stratosphere (LMS) is determined. The study shows that the transport of air masses originating from the Asian summer monsoon region within the lower stratosphere affects the change in the chemical composition of the Ex-UTLS over Europe and thus contributes to the flushing of the LMS during summer 2012.
We present an estimation of the uptake coefficient (γ) and yield of nitryl chloride (ClNO2) (f) for the heterogeneous processing of dinitrogen pentoxide (N2O5) using simultaneous measurements of particle and trace gas composition at a semi-rural, non-coastal, mountain site in the summer of 2011. The yield of ClNO2 varied between (0.035 ± 0.027) and (1.38 ± 0.60) with a campaign average of (0.49 ± 0.35). The large variability in f reflects the highly variable chloride content of particles at the site. Uptake coefficients were also highly variable with minimum, maximum and average γ values of 0.004, 0.11 and 0.028 ± 0.029, respectively, with no significant correlation with particle composition, but a weak dependence on relative humidity. The uptake coefficients obtained are compared to existing parameterisations based on laboratory datasets and with other values obtained by analysis of field data.
We present an estimation of the uptake coefficient (γ) and yield of nitryl chloride (ClNO2) (f) for the heterogeneous processing of dinitrogen pentoxide (N2O5) using simultaneous measurements of particle and trace gas composition at a semi-rural, non-coastal, mountain site in the summer of 2011. The yield of ClNO2 varied between (0.035 ± 0.027) and (1.38 ± 0.60) with a campaign average of (0.49 ± 0.35). The large variability in f reflects the highly variable chloride content of particles at the site. Uptake coefficients were also highly variable with minimum, maximum and average γ values of 0.004, 0.11 and 0.028 ± 0.029, respectively, with no significant correlation with particle composition, but a weak dependence on relative humidity. The uptake coefficients obtained are compared to existing parameterizations based on laboratory datasets and with other values obtained by analysis of field data.
The exact mechanisms for new particle formation (NPF) under different boundary layer conditions are not known yet. One important question is if amines and sulfuric acid lead to efficient NPF in the atmosphere. Furthermore, it is not clear to what extent highly oxidized organic molecules (HOM) are involved in NPF. We conducted field measurements at a rural site in central Germany in the proximity of three larger dairy farms to investigate if there is a connection between NPF and the presence of amines and/or ammonia due to the local emissions from the farms. Comprehensive measurements using a nitrate Chemical Ionization-Atmospheric Pressure interface-Time Of Flight (CI-APi-TOF) mass spectrometer, a Proton Transfer Reaction-Mass Spectrometer (PTR-MS), particle counters and Differential Mobility Analyzers (DMAs) as well as measurements of trace gases and meteorological parameters were performed. It is shown that the nitrate CI-APi-TOF is suitable for sensitive measurements of sulfuric acid, amines, a nitrosamine, ammonia, iodic acid and HOM. NPF was found to correlate with sulfuric acid, while an anti-correlation with RH, amines and ammonia is observed. The anti-correlation between NPF and amines could be due to the efficient uptake of these compounds by nucleating clusters and small particles. Much higher HOM dimer (C19/C20 compounds) concentrations during the night than during the day indicate that these HOM do not efficiently self-nucleate as no night-time NPF is observed. Observed iodic acid probably originates from an iodine-containing reservoir substance but the iodine signals are very likely too low to have a significant effect on NPF.
The exact mechanisms for new particle formation (NPF) under different boundary layer conditions are not known yet. One important question is whether amines and sulfuric acid lead to efficient NPF in the atmosphere. Furthermore, it is not clear to what extent highly oxidized organic molecules (HOMs) are involved in NPF. We conducted field measurements at a rural site in central Germany in the proximity of three larger dairy farms to investigate whether there is a connection between NPF and the presence of amines and/or ammonia due to the local emissions from the farms. Comprehensive measurements using a nitrate chemical ionization–atmospheric pressure interface time-of-flight (CI-APi-TOF) mass spectrometer, a proton-transfer-reaction mass spectrometer (PTR-MS), particle counters and differential mobility analyzers (DMAs), as well as measurements of trace gases and meteorological parameters, were performed. We demonstrate here that the nitrate CI-APi-TOF is suitable for sensitive measurements of sulfuric acid, amines, a nitrosamine, ammonia, iodic acid and HOMs. NPF was found to correlate with sulfuric acid, while an anti-correlation with RH, amines and ammonia is observed. The anti-correlation between NPF and amines could be due to the efficient uptake of these compounds by nucleating clusters and small particles. Much higher HOM dimer (C19/C20 compounds) concentrations during the night than during the day indicate that these HOMs do not efficiently self-nucleate as no nighttime NPF is observed. Observed iodic acid probably originates from an iodine-containing reservoir substance, but the iodine signals are very likely too low to have a significant effect on NPF.
A new global synthesis and biomization of long (> 40 kyr) pollen-data records is presented and used with simulations from the HadCM3 and FAMOUS climate models and the BIOME4 vegetation model to analyse the dynamics of the global terrestrial biosphere and carbon storage over the last glacial–interglacial cycle. Simulated biome distributions using BIOME4 driven by HadCM3 and FAMOUS at the global scale over time generally agree well with those inferred from pollen data. Global average areas of grassland and dry shrubland, desert, and tundra biomes show large-scale increases during the Last Glacial Maximum, between ca. 64 and 74 ka BP and cool substages of Marine Isotope Stage 5, at the expense of the tropical forest, warm-temperate forest, and temperate forest biomes. These changes are reflected in BIOME4 simulations of global net primary productivity, showing good agreement between the two models. Such changes are likely to affect terrestrial carbon storage, which in turn influences the stable carbon isotopic composition of seawater as terrestrial carbon is depleted in 13C.
New particle formation driven by acid–base chemistry was initiated in the CLOUD chamber at CERN by introducing atmospherically relevant levels of gas-phase sulfuric acid and dimethylamine (DMA). Ammonia was also present in the chamber as a gas-phase contaminant from earlier experiments. The composition of particles with volume median diameters (VMDs) as small as 10 nm was measured by the Thermal Desorption Chemical Ionization Mass Spectrometer (TDCIMS). Particulate ammonium-to-dimethylaminium ratios were higher than the gas-phase ammonia-to-DMA ratios, suggesting preferential uptake of ammonia over DMA for the collected 10–30 nm VMD particles. This behavior is not consistent with present nanoparticle physicochemical models, which predict a higher dimethylaminium fraction when NH3 and DMA are present at similar gas-phase concentrations. Despite the presence in the gas phase of at least 100 times higher base concentrations than sulfuric acid, the recently formed particles always had measured base : acid ratios lower than 1 : 1. The lowest base fractions were found in particles below 15 nm VMD, with a strong size-dependent composition gradient. The reasons for the very acidic composition remain uncertain, but a plausible explanation is that the particles did not reach thermodynamic equilibrium with respect to the bases due to rapid heterogeneous conversion of SO2 to sulfate. These results indicate that sulfuric acid does not require stabilization by ammonium or dimethylaminium as acid–base pairs in particles as small as 10 nm.
New particle formation driven by acid-base chemistry was initiated in the CLOUD chamber at CERN by introducing atmospherically relevant levels of gas phase sulfuric acid and dimethylamine (DMA). Ammonia was also present in the chamber as a gas-phase contaminant from earlier experiments. The composition of particles with volume median diameters (VMDs) as small as 10 nm was measured by the Thermal Desorption Chemical Ionization Mass Spectrometer (TDCIMS). Particulate ammonium-to-dimethylaminium ratios were higher than the gas phase ammonia-to-DMA ratios, suggesting preferential uptake of ammonia over DMA for the collected 10-30 nm VMD particles. This behavior is not consistent with present nanoparticle physico-chemical models, which predict a higher dimethylaminium fraction when NH3 and DMA are present at similar gas phase concentrations. Despite the presence in the gas phase of at least 100 times higher base concentrations than sulfuric acid, the recently formed particles always had measured base:acid ratios lower than 1:1. The lowest base fractions were found in particles below 15 nm VMD, with a strong size-dependent composition gradient that suggests a change to a mixed-phase state as the particles grew beyond this size. The reasons for the very acidic composition remain uncertain, but a possible explanation is that the particles did not reach thermodynamic equilibrium with respect to the bases due to rapid heterogeneous conversion of SO2 to sulfate. These results indicate that sulfuric acid does not require stabilization by ammonium or dimethylaminium as acid-base pairs in particles as small as 10 nm.
A new global synthesis and biomization of long (> 40 kyr) pollen-data records is presented, and used with simulations from the HadCM3 and FAMOUS climate models to analyse the dynamics of the global terrestrial biosphere and carbon storage over the last glacial–interglacial cycle. Global modelled (BIOME4) biome distributions over time generally agree well with those inferred from pollen data. The two climate models show good agreement in global net primary productivity (NPP). NPP is strongly influenced by atmospheric carbon dioxide (CO2) concentrations through CO2 fertilization. The combined effects of modelled changes in vegetation and (via a simple model) soil carbon result in a global terrestrial carbon storage at the Last Glacial Maximum that is 210–470 Pg C less than in pre-industrial time. Without the contribution from exposed glacial continental shelves the reduction would be larger, 330–960 Pg C. Other intervals of low terrestrial carbon storage include stadial intervals at 108 and 85 kaBP, and between 60 and 65 kaBP during Marine Isotope Stage 4. Terrestrial carbon storage, determined by the balance of global NPP and decomposition, influences the stable carbon isotope composition (δ 13C) of seawater because terrestrial organic carbon is depleted in 13C. Using a simple carbon-isotope mass balance equation we find agreement in trends between modelled ocean δ 13C based on modelled land carbon storage, and palaeo-archives of ocean δ 13C, confirming that terrestrial carbon storage variations may be important drivers of ocean δ 13 C changes.
Law and literature: that is a sufficiently broad subject to warrant reference to the Fontane character Effy Briest’s "wide field." Indeed, the sites where law and literature encounter each other, where they border on each other, merge, converge, overlap, or where they relate as opposites, even finding themselves as rivals or enemies seem legion. In contrast to the intentions of Effy Briest in that famous novel, my reference to this line is not intended to abort further inquiries; instead I want to chart the field in question with the aim of developing a preliminary typology of the ways in which law and literature have been engaged and have engaged one another. Against the background of this overview, I want to turn to a much smaller field. This small field - a plot of long fallow farmland, to be exact, located between two adjacent, perfectly maintained wheat fields in a fictive Swiss village - will serve as an example or test site for "law and literature" as they emerge in Gottfried Keller’s narrative 'Romeo und Julia auf dem Dorfe', from his mid-nineteenth century collection of novellas 'Die Leute von Seldwyla'. Whether and how the case study of that small field at the centre of Keller’s story can make a case for the larger field of "law and literature" remains to be seen.
Was den Tragödien zwischen Lessing und Hebbel an Tragik fehlen mag, muß der tragische Verlauf der (Literatur-)Geschichte wettmachen. Als Nietzsche im Jahr der Veröffentlichung von Grillparzers "Jüdin von Toledo" mit seiner "Geburt der Tragödie" den literarischen Gattungsbegriff um das Phänomen 'tragischer Erkenntnis' erweiterte, stellte er jenen frei flottierenden Tragikbegriff zur Verfügung, der seitdem sein Unwesen bis zu Benno von Wiese getrieben hat. Dessen Buch zur deutschen Tragödie entstand im historischpolitischen Umfeld jener Jahre, die vor allem unmittelbar nach 1945 und gelegentlich auch heute noch als 'deutsche Tragödie' euphemistisch umschrieben werden. Die in beiden Fällen fatalen Implikationen der notorischen Vermischung von literarischen Begriffen bzw. literarischen Verfahren mit politischen Semantiken oder historischen Verläufen ist Grund genug, zunächst einmal auf ihrem Unterschied zu beharren, auch und gerade im Falle von Tragödien - so es denn solche gibt. Aber auch wer im Vertrauen darauf, daß gegangene Wege der Nietzsche-Rezeption tragischer Konsequenz entbehren, Askese üben und der Differenz zwischen literarischen und historischen Verläufen Rechnung tragen möchte, wird an der lange vor Nietzsches Tragödienbuch, nämlich schon um 1848 verfaßten, aber erst 1872 kurz nach Grillparzers Tod veröffentlichten "Jüdin von Toledo" scheitern. Zu kraß ist dieses Stück, als daß man ästhetische Strukturen und politische Implikate hier sauber trennen könnte. Genauso unmöglich ist es aber, ihren Zusammenhang im Zeichen der Tragik zu stiften.
Als der Positivismus auf allen Fronten, insbesondere derjenigen der 'harten' Wissenschaften wie Physik und Mathematik, in die berühmte Grundlagenkrise geraten war, richtete sich das Interesse der Kulturwissenschaften am Anfang des 20. Jahrhunderts auf eine Neubestimmung von Natur und Geist. Der geheime Fluchtpunkt, das flüssige Substrat dieser sehr heterogenen intellektuellen Anstrengungen hieß damals häufig: Leben. Im Sog solcher Strömungen gelangte auch Goethes Metamorphosen-Lehre zu neuer Geltung. Nach Jahrzehnten der Latenz und Ridikülisierung durch Haeckels 1866 erschienene 'Generelle Morphologie der Organismen' in Zusammenhang mit Darwin gebracht und deszendenztheoretisch aktualisiert, begann die Metamorphose nach der Jahrhundertwende in zahlreichen anderen und keineswegs nur monistischen Zusammenhängen nachgerade zu wuchern: bei Kulturwissenschaftlern wie Simmel und Cassirer, in der idealistischen Biologie, bei rationalitätskritischen Lebensphilosophen wie Spengler und Klages, unter Kunst- und später Literaturwissenschaftlern wie Worringer, Wölfflin, Walzel, Jolles, Günther Müller, bei Künstlern wie Rilke, Einstein und Kafka. In einem Kapitel mit der Überschrift "Zur ideologischen Morphologie der literarischen Bestiae" nahm Franz Bleis 1922 erschienenes 'Bestiarium der Modernen Literatur' die Morphologie-Mode bereits satirisch-kritisch in den Blick.
Wem es an eigener Erfahrung oder Anschauung mangelt, der kann sich u.a. von Theweleit darüber belehren lassen, dass beim Fußball viel gelitten wird. Auch der Fan ist alles andere als ein 'standhafter Zuschauer ästhetischer Leiden', denn er leidet wahrhaftig und sozusagen leibhaft mit. Darin ist und bleibt, mit Verlaub, auch der moderne Fußball ein so archaisches Phänomen wie, sagen wir, die sophokleische Tragödie, in der auch viel gelitten wird und die auch keine Zuschauer, sondern ausschließlich Ritualteilnehmer kennt. Mit dem Leidensbegriff, den die moderne Kultur ausgebildet hat, hat der Fußball nichts zu tun, eher schon fungiert er als Gegengift für Kulturleidende. Man kann sich kaum vorstellen, dass Adorno von diesem Mittel Gebrauch gemacht haben sollte. O-Ton Youtube: "[M]an muß […] daran erinnern, daß die Menschen, die also auf dem Sportfeld zuschauen und zwar in allen Ländern […], gegen die Fremdgruppe, also gegen das ausländische Team, sich in einer Weise benehmen, die den einfachsten Anforderungen der Gastfreundschaft [...] aufs Krasseste widerspricht." Nun ja; Adorno war eben Theoretiker von "Gruppenverhalten" und als Fußball-Fan ist er so schwer vorstellbar wie als Spieler. Oder doch? Gibt es vielleicht auch bei ihm Rudimente eines Fan-Begehrens, die nicht in der Analyse von Gruppenverhalten aufgehen und theorieimmanente Selbst-Widerstände artikulieren? Dagegen spricht vorläufig die übermächtige Tradition des Leidens an der Kultur, der Adorno ganz ohne Zweifel verhaftet ist, eben weil er ihr Fan nicht sein konnte oder wollte.
Before turning to the essay on the experiment from 1793, which is unavoidable when discussing series, but does not exhaust the varied functions of seriality in Goethe’s morphology, a few words about the purpose of reconstructing Goethe’s practice of seriality are necessary. I want to argue that Goethe’s morphology is the site of a massive transformation of the notion of form, the scope and implications of which resurface after long latency at the beginning of the 20th century, for example, with Georg Simmel’s sociological notion of form-processes and the related idea of "reciprocity" ('Wechselwirkung') (cf. 265). My interest lies in interpreting what looks like a theory of organisms and nature as a more general theory of formation and transformation.
Die Tatsache, dass Benjamins Schreiben in vielen Fällen zu keiner abgeschlossenen Gestalt geführt und sich nicht immer zu einem 'Text' gefügt hat, erfordert dringend eine produktionsästhetische Perspektive, die das Augenmerk mit Entschiedenheit auf die Entstehungsprozesse lenkt. In diesem Punkt kann die Benjamin-Forschung Neuland betreten. Was damit zudem zur Diskussion steht, ist nichts Geringeres als eine überlieferungsgeschichtliche Revision ihrer textuellen Grundlage. Was heute als Texte Benjamins gelesen werden kann, ist das Resultat von jahrzehntelanger Werkpolitik. Sie unterliegen einer editorisch hergestellten Suggestion von Abgeschlossenheit, die sie aber in der Logik von Benjamins Produktion häufig nicht besitzen. Alles, was aus dem Nachlass an Aufzeichnungen, Notizen, Entwürfen, Arbeitshandschriften überliefert ist und in den Archiven schlummert, ist vielmehr Zeuge eines infiniten 'work in progress', der sich nicht in ein werkästhetisches Korsett zwingen lässt. Im Folgenden wird an einer kleinen, aber prominenten Aufzeichnung Benjamins materiale Poetik des Schreibens exemplarisch veranschaulicht. Die Fragen nach den Implikationen und Konsequenzen für den interpretatorischen und überlieferungskritischen Umgang mit seinen nachgelassenen Schriften stehen dabei im Vordergrund.
In a letter to Scholem, dated 22 December, 1924, Benjamin famously writes of the manuscript that was to become his 'Trauerspiel' book: "[I]ndessen überrascht mich nun vor allem, daß, wenn man so will, das Geschriebene fast ganz aus Zitaten besteht" (GS I.3, 881). Much has been made of the mosaic-like citational technique to which Benjamin refers here; his "Zitatbegriff" is said, for example, to subtend the theory of a "mikrologische Verarbeitung" of "Denkbruchstücken" into "Ideen" that Benjamin develops as his theory of representation in the "Erkenntniskritische Vorrede", which in turn figures the relation between individual phenomena and their "ideas" in astral terms. Because, however, the 'Trauerspiel' book is so often understood only on this theoretical level, e.g. as either an early articulation of Benjamin’s "avant garde" and "messianic" philosophy of history (Jäger, Kany, and Pizer) or as a performance of his systems of allegory (Menninghaus) and "constructivism" (Schöttker), his "Zitierpraxis" and the actual citations that form large parts of 'Der Ursprung des deutschen Trauerspiel' have seldom been read for the purchase they provide on the vexed status of the period and concept that was the book’s direct subject, namely, the German Baroque.
Bei Walter Benjamin steht die Moderne im Zeichen des Verlusts. Denn er fasst Moderne nicht als Erfüllung vorgeformter Geschichte, sondern in den Spuren ihres Verschwindens. Zum Schauplatz dieser negativen Gründungsfigur wird für Benjamin der Begriff der Erfahrung. Modern ist, wer um die Erfahrung gebracht worden ist. Und so schildert Benjamin den Dichter, der von einer Ecke aus, das Glücksspiel beobachtet, als einen um seine Erfahrung gebrachten: "Der Dichter nimmt nicht am Spiele teil. Er steht in seiner Ecke; nicht glücklicher als sie, die Spielenden. Er ist auch ein um seine Erfahrung betrogener Mann, ein Moderner." (GS I, 636) Das Erkennen der Moderne im Zeichen des Verlusts und Betrogenseins entsteht durch eine Rückschau. Im zurückgewendeten Blick erscheint Moderne in der Differenz von Vergangenem und Gegenwärtigem, von vormaliger Fülle und Mangel im Jetzt. Bei aller "Schönheit" (GS II, 442), die Benjamin dabei dem Entschwinden abgewinnt, ist die vollzogene Figur melancholische Trope. Aus der melancholischen Differenz heraus scheint die Kontinuität der translatio abgebrochen. Auf diesen Bruch richtet Benjamin immer wieder seinen Blick, ob er nun über die veränderten Rezeptionsbedingungen von Kunst im "Zeitalter technischer Reproduzierbarkeit" spricht oder über den Unterschied von Roman und Erzählung. Während die Erzählung bei Benjamin für das Einst einsteht, in dem Erfahrung noch tradierbar war, bedeutet die Moderne des Romans demgegenüber einen irreversiblen Verlust des Austauschs von Erfahrungen: "Es ist, als wenn ein Vermögen, das uns unveräußerlich schien, das Gesichtertste unter dem Sicheren, von uns genommen würde. Nämlich das Vermögen Erfahrungen auszutauschen." (GS II, 439)1 Was uns "genommen wurde", scheint auf immer verloren und daher ist, was uns offenbar ausweglos bleibt: Die Melancholie. Jedoch bietet Benjamin selbst eine Perspektive an, wie mit dieser Figur der Moderne umzugehen ist und somit einen Ausweg aus der Melancholie heraus. Dieser Ausweg zeigt sich im Begriff der Übung an. Denn Übung bei Benjamin - und das möchte ich zeigen - ist doppelt markiert: Sie steht zum einen für jenes Einst an Erfahrung, das mit der Moderne verschwunden ist. Zum anderen ist sie das, was die Moderne weiterbringt. Sie trainiert den Körper, schult die Sinne. Kurz: Sie übt im Umgang mit der Technik und damit im Umgang mit der Moderne. Allerdings - und das ist die Crux an der ganzen Sache -, ist sie dabei stets in Gefahr: Umzuschlagen nämlich in Dressur, um damit den Menschen der Technik zu unterwerfen. Dass Benjamin diesen feinen Unterschied gesehen hat, darin besteht seine Aktualität. Sie steht dabei ganz im Licht der Antike. Denn mit dem Begriff der Übung und seinem unterschiedlichen, doppelten Gebrauch aktualisiert er ein geläufiges Verfahren der Antike. Entgegen seiner eigenen Insistenz auf Verlustfiguren wie den "Abschied für ewig" (GS I, 623) oder der "Liebe [...] auf den letzten Blick" (ebd.), führt seine Verwendung der Übung vor, dass die Moderne selbst in ihren melancholischsten Zügen und der Verlustmarkierung der Erfahrung, sich übend mit ihren eigenen Bedingungen auseinandersetzt und auf diese Weise die abgebrochene Erfahrung gänzlich unmelancholisch wieder ins Spiel bringt.
BACKGROUND: Recent findings support the idea that interleukin (IL)-22 serum levels are related to disease severity in end-stage liver disease. Existing scoring systems--Model for End-Stage Liver Disease (MELD), Survival Outcomes Following Liver Transplantation (SOFT) and Pre-allocation-SOFT (P-SOFT)--are well-established in appraising survival rates with or without liver transplantation. We tested the hypothesis that IL-22 serum levels at transplantation date correlate with survival and potentially have value as a predictive factor for survival.
MATERIAL AND METHODS: MELD, SOFT, and P-SOFT scores were calculated to estimate post-transplantation survival. Serum levels of IL-22, IL-6, IL-10, C-reactive protein (CRP), and procalcitonin (PCT) were collected prior to transplantation in 41 patients. Outcomes were assessed at 3 months, 1 year, and 3 years after transplantation.
RESULTS: IL-22 significantly correlated with MELD, P-SOFT, and SOFT scores (Rs 0.35, 0.63, 0.56 respectively, p<0.05) and with the discrimination in post-transplantation survival. IL-6 showed a heterogeneous pattern (Rs 0.40, 0.63, 0.57, respectively, p<0.05); CRP and PCT did not correlate. We therefore added IL-22 serum values to existing scoring systems in a generalized linear model (GLM), resulting in a significantly improved outcome prediction in 58% of the cases for both the P-SOFT (p<0.01) and SOFT scores (p<0.001).
CONCLUSIONS: Further studies are needed to address the concept that IL-22 serum values at the time of transplantation provide valuable information about survival rates following orthotopic liver transplantation.
Die hämatopoetische Stammzelltransplantation (HSZT) stellt für zahlreiche Erkrankungen die einzige Chance auf Heilung dar. Gleichzeitig ist dieses Therapieverfahren mit einer hohen Morbidität und Mortalität verbunden, welche auf diverse akute Nebenwirkungen aber auch langfristige Komplikationen zurückzuführen ist. Unter anderem wurden vielfältige Funktionsbeeinträchtigungen erfasst, welche in einer gravierenden körperlichen Dekonditionierung sowie einem erhöhtem Risiko für kardiovaskuläre Folgeerkrankungen münden können. Sport- und Bewegungstherapie konnte sich in diesem Rahmen als Supportivmaßnahme vor allem bei erwachsenen Krebspatienten etablieren. Die Studienlage für Kinder und Adoleszenten mit Krebs ist nicht gleichsam evident. In der pädiatrischen SZT gibt es bis dato lediglich vier international publizierte Studien. Aufgrund des skizzierten Forschungsdefizits, sollten im Rahmen der vorliegenden randomisiert-kontrollierten Untersuchung, die physischen und psychischen Effekte einer strukturierten Sporttherapie während und nach der HSZT evaluiert werden.
Die erste Studienphase bezieht sich auf die stationäre Behandlung der Patienten und wurde in einem randomisiert-kontrollierten Design durchgeführt. Mit stationärer Aufnahme wurden teilnehmende Probanden in eine von zwei Studiengruppen randomisiert (Interventionsgruppe (IG) oder Kontrollgruppe (KG)). Während die IG ein Ausdauer-, Kraft- und Beweglichkeitstraining erhielt, führte die KG Konzentrations- und Entspannungsübungen durch. Beiden Gruppen wurde das altersentsprechende sowie individualisierte Training täglich zwischen 30–60min angeboten. Mit stationärer Entlassung gingen die Patienten in Phase II, die ambulante Nachbehandlung über. In dieser Pilotstudie sollten neben der Machbarkeit von Sporttherapie, die physischen Effekte bis 6 Monate nach HSZT analysiert werden. Aufgrund der wohnortgestützten ambulanten Weiterbehandlung wurde eine Neu-Stratifizierung der Patienten durchgeführt, wodurch vier Gruppen entstanden: IG–IG, IG–KG, KG–IG und KG–KG. Als MZP dienten die stationäre Aufnahme (T0) und Entlassung (T1) sowie für die Phase II Tag+100 (T2) und Tag+200 (T3). Die Testungen inkludierten motorische Testverfahren (6-Minuten-Walking-Test (6MWT), Spiroergometrie, Handkraft (Hk), Beinkraft (Bk)), psychometrische Testverfahren (Lebensqualität (LQ)) sowie klinische Parameter (z.B. Blutwerte) und die Körperzusammensetzung.
In vier Studienjahren (2011-2014) wurden 70 Patienten mit einem mittleren Alter von 11,0 Jahren (5–18Jahre) eingeschlossen. Stationär kam es zu einer Drop out Rate von 18,6% sowie zu Tag+200 von 54,3%. Die Patientencharakteristika zeigten abgesehen vom BMI bei Aufnahme (p<.05) keine Gruppenunterschiede.
Das stationäre Training wurde von beiden Gruppen mit 3,1 (2–4; IG) bzw. 2,9 (0,3–4; KG) Trainingseinheiten pro Woche ähnlich gut angenommen (je ~51min/Trainingseinheit). Für drei von den vier motorischen Testverfahren zeigte sich anhand der relativen Veränderungen für die IG ein Erhalt der Leistungsfähigkeit (6MWT: 2,4 (-66,1–25,7)%; Hk: -3,6±16,3%; Bk: -1,6 (-52,6–144,4)%). Gleichzeitig reduzierte die KG diese Daten jeweils signifikant (6MWT: -14,6 (-73,2–18,0)%; Hk: -10,9±20,0%; Bk: -13,0 (-57,9–131,7)%; p<.05). Die VO2peak ml/kg/min der Spiroergometrie zeigte innerhalb beider Gruppen eine signifikante Verschlechterung (IG: 15,0±16,7%; KG: -18,7±22,7%; p<.05). Die LQ präsentierte dagegen ein uneinheitliches Bild für beide Studiengruppen. Für die Körperzusammensetzung und klinischen Parameter konnten keine signifikanten Unterschiede berechnet werden.
Im ambulanten Setting demonstrierte die Aufbereitung des Trainings eine generelle Machbarkeit. Das Training wurde in 53,6±10,2% der Ambulanztermine integriert. Die hohe Ausfallrate war primär auf Kontraindikationen (63,3±22,1%) und Sondertermine (14,6±7,0%) zurückzuführen. Die Trainingshäufigkeit belief sich insgesamt auf 0,7 Trainingseinheiten/Woche bei 42,5min pro Trainingseinheit. Die Betrachtung der physischen Effekte zeigte eine generelle Verbesserung der Daten innerhalb aller Gruppen. Gruppen mit sportlicher Intervention (stationär oder ambulant) wiesen partiell (6MWT, Bk) höhere Messwerte und Verbesserungen auf. Signifikanzen lagen keine vor.
Gesamt betrachtet konnte in Studienphase 1 dem therapieassoziiertem körperlichen Abbau durch Bewegungstherapie entgegengewirkt werden. Gleichzeitig zeigte das Assessment, ausgenommen LQ, Körperzusammensetzung sowie die Spiroergometrie eine gute Anwendbarkeit in dem Setting. Für die ambulante Studienphase kann eine generelle Machbarkeit von Sporttherapie nach HSZT postuliert werden. Weitere Erhebungen wären in diesem Setting hinsichtlich der Trainingseffekte noch erforderlich. Zukünftige Studien sollten multizentrisch durchgeführt werden, um mit Hilfe größerer Fallzahlen umfassendere Erkenntnisse zu erlangen.