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ω-Azido fatty acids as probes to detect fatty acid biosynthesis, degradation, and modification
(2014)
FAs play a central role in the metabolism of almost all known cellular life forms. Although GC-MS is regarded as a standard method for FA analysis, other methods, such as HPLC/MS, are nowadays widespread but are rarely applied to FA analysis. Here we present azido-FAs as probes that can be used to study FA biosynthesis (elongation, desaturation) or degradation (β-oxidation) upon their uptake, activation, and metabolic conversion. These azido-FAs are readily accessible by chemical synthesis and their matization with high sensitivity by HPLC/MS, contributing a powerful tool to FA analysis, and hence, lipid analysis in general.
Four species of mole crickets (Orthoptera: Gryllotalpidae) are known from the West Indies: Neocurtilla hexadactyla (Perty), Scapteriscus abbreviatus Scudder, S. didactylus (Latreille), and S. imitatus Nickle and Castner. All are adventive (not native). We document their distributions in West Indian islands/countries by use of records from the literature and examination of specimens. Scapteriscus abbreviatus has been suggested to have arrived in, and been transported about the West Indies in ship ballast (immigration). Based on records of arrival in various parts of the West Indies and the species’ inability to fly, this suggestion seems reasonable. Scapteriscus imitatus pparently was released in Puerto Rico as a result of mistaken identification (introduction – arriving with assistance from humans – although inadvertent), and has not expanded its range in the West Indies. Although the principal mode of dispersal for the other two species also has been suggested to be ship ballast, we present an alternative based on flight which would seem at least equally as plausible. We suggest that S. didactylus could have dispersed by flight from South America through the Lesser Antilles; likewise N. hexadactyla probably from the Yucatan Peninsula to Cuba, and from South America northward through the Lesser Antilles, in at least some localities assisted by wind. Our zoogeographical alternative, if correct, means that the natural range expansions of these latter two species began very long ago and without human assistance – they were not introduced recently to the West Indies.
The traffic AAA-ATPase PilF is essential for pilus biogenesis and natural transformation of Thermus thermophilus HB27. Recently, we showed that PilF forms hexameric complexes containing six zinc atoms coordinated by conserved tetracysteine motifs. Here we report that zinc binding is essential for complex stability. However, zinc binding is neither required for pilus biogenesis nor natural transformation. A number of the mutants did not exhibit any pili during growth at 64 °C but still were transformable. This leads to the conclusion that type 4 pili and the DNA translocator are distinct systems. At lower growth temperatures (55 °C) the zinc-depleted multiple cysteine mutants were hyperpiliated but defective in pilus-mediated twitching motility. This provides evidence that zinc binding is essential for the role of PilF in pilus dynamics. Moreover, we found that zinc binding is essential for complex stability but dispensable for ATPase activity. In contrast to many polymerization ATPases from mesophilic bacteria, ATP binding is not required for PilF complex formation; however, it significantly increases complex stability. These data suggest that zinc and ATP binding increase complex stability that is important for functionality of PilF under extreme environmental conditions.
Three years after the advent of Zimbabwe's Inclusive Government in February 2009, the country still awaits the elections that people hope will lead to a more enduring political settlement. Zimbabwe: Mired in Transition reviews the experience of recent years assesses the progress that has been made. What is the public mood, and how has it changed? What steps have been taken to reform the media? How important is a new constitution. Although the economy has stabilised to some extent with the adoption of a multi-currency regime, industrial and agricultural production are depressed, and investment inflows are limited; what spaces exist for fiscal reform? Are local authority structures and the state bureaucracy equipped to handle the tasks that will ne asked of them? In terms of two important areas, the book extends its analysis further back than 2009. First, is the issue of emigration. Estimates of the number of Zimbabweans in the diaspora range from three to four million; what impact us this having on national development, and to what extent might the trend of migration be reversed? The second concerns young people, the chapter on which concludes: 'We already have a 'lost generation' - those who were once called the 'born frees'. Unless positive changes are made, we will still have another'. This collection of eleven essays examines in detail some of the pressing questions which Zimbabweans must ask as they chart a way forward.
You reap what you sow! differences in knowledge exchange effectiveness between communication types
(2014)
FOR KNOWLEDGE-INTENSIVE ORGANIZATIONS IN THE FINANCE INDUSTRY, AN EFFECTIVE KNOWLEDGE EXCHANGE AMONG EMPLOYEES IS CRUCIAL FOR THE COMPETITIVE PERFORMANCE. THEREFORE, COMPANIES INCREASINGLY RELY ON SOCIAL MEDIA PLATFORMS TO FACILITATE COMMUNICATION AND COLLABORATION. TO ENHANCE OUR UNDERSTANDING OF SUCCESSFUL COMMUNICATION IN ENTERPRISE SOCIAL MEDIA, WE APPLY HUMAN CODING AND QUANTITATIVE ANALYSIS TO THE CONTENT AND TONE OF 15,505 ENTERPRISE MICROBLOGGING MESSAGES CREATED BY 1,166 EMPLOYEES OF AN INTERNATIONAL FINANCIAL SERVICE PROVIDER. OUR RESULTS SUGGEST THAT A MORE FACTUAL-ORIENTED COMMUNICATION TYPE BENEFITS FROM A HIGHER KNOWLEDGE EXCHANGE EFFECTIVENESS COMPARED TO A PRIMARILY SELF-DISCLOSING COMMUNICATION TYPE.
Wrack burial reduces germination and establishment of the invasive cordgrass Spartina densiflora
(2014)
Germination and emergence of halophytes may decrease significantly by seed burial in dead plant material, or wrack, which is common and abundant in tidal marshes. The effects of plant debris (wrack) burial on seed germination and seedling establishment of Spartina densiflora, an invasive cordgrass, were studied under greenhouse conditions and compared with field observations. Five wrack burial depths were applied: control without wrack, 1 cm (1235 ± 92 g DW wrack m-2), 2 cm (3266 ± 13 g DW m-2), 4 cm (4213 ± 277 g DW m-2), and 8 cm (6138 ± 227 g DW m-2). Sediment pH, electrical conductivity, redox potential and temperature were recorded. Quiescence increased with wrack load up to ~20% at 8 cm deep. Germination decreased with wrack load from 96% to 14%, which could be related with anoxic conditions under the debris since sediment redox potential was as low as -83 ± 7 mV at 8 cm. Germination percentage increased and quiescent and dormant percentages decreased at higher daily sediment temperatures and with higher daily temperature fluctuations, conditions that were recorded without or under low loads of wrack. Spartina densiflora did not show primary dormancy, but its seeds entered into a non-deep physiological dormancy below 1 cm deep in plant debris. The establishment of S. densiflora seedlings was also greatly reduced by wrack burial since only 6 seedlings (11 ± 5 % of germinated seeds) emerged above plant debris from 1 cm and all seedlings died from deeper than 1 cm. S. densiflora seedling development was also reduced by wrack burial. The inverse relationship between germination and emergence of S. densiflora with wrack burial recorded in our study is useful to predict its invasion dynamics and to plan the management of invaded marshes.
This book addresses itself to mobilisation and involvement of rural people in development projects. It describes an imperfect but, nonetheless, exciting and thought-provoking exercise that drew social science researchers and students from four public universities in Kenya into an experiment in participatory research, community education and development in two locations. The experiment was grounded on the assumptions that the people of Kenya are a primary resource and that given proper roles and contribution of planners, researchers and programme implementers, self-sustainable development can become a reality. The contributors of this book have focused on the potential of the university to facilitate participation of the people in development. They have given specific suggestions on how this might be accomplished.
This paper investigates the determinants of value and growth investing in a large administrative panel of Swedish residents over the 1999-2007 period. We document strong relationships between a household’s portfolio tilt and the household’s financial and demographic characteristics. Value investors have higher financial and real estate wealth, lower leverage, lower income risk, lower human capital, and are more likely to be female than the average growth investor. Households actively migrate to value stocks over the life-cycle and, at higher frequencies, dynamically offset the passive variations in the value tilt induced by market movements. We verify that these results are not driven by cohort effects, financial sophistication, biases toward popular or professionally close stocks, or unobserved heterogeneity in preferences. We relate these household-level results to some of the leading explanations of the value premium.
Abstract Trial-to-trial variability and spontaneous activity of cortical recordings have been suggested to reflect intrinsic noise. This view is currently challenged by mounting evidence for structure in these phenomena: Trial-to-trial variability decreases following stimulus onset and can be predicted by previous spontaneous activity. This spontaneous activity is similar in magnitude and structure to evoked activity and can predict decisions. Allof the observed neuronal properties described above can be accounted for, at an abstract computational level, by the sampling-hypothesis, according to which response variability reflects stimulus uncertainty. However, a mechanistic explanation at the level of neural circuit dynamics is still missing.
In this study, we demonstrate that all of these phenomena can be accounted for by a noise-free self-organizing recurrent neural network model (SORN). It combines spike-timing dependent plasticity (STDP) and homeostatic mechanisms in a deterministic network of excitatory and inhibitory McCulloch-Pitts neurons. The network self-organizes to spatio-temporally varying input sequences.
We find that the key properties of neural variability mentioned above develop in this model as the network learns to perform sampling-like inference. Importantly, the model shows high trial-to-trial variability although it is fully deterministic. This suggests that the trial-to-trial variability in neural recordings may not reflect intrinsic noise. Rather, it may reflect a deterministic approximation of sampling-like learning and inference. The simplicity of the model suggests that these correlates of the sampling theory are canonical properties of recurrent networks that learn with a combination of STDP and homeostatic plasticity mechanisms.
Author Summary Neural recordings seem very noisy. If the exact same stimulus is shown to an animal multiple times, the neural response will vary. In fact, the activity of a single neuron shows many features of a stochastic process. Furthermore, in the absence of a sensory stimulus, cortical spontaneous activity has a magnitude comparable to the activity observed during stimulus presentation. These findings have led to a widespread belief that neural activity is indeed very noisy. However, recent evidence indicates that individual neurons can operate very reliably and that the spontaneous activity in the brain is highly structured, suggesting that much of the noise may in fact be signal. One hypothesis regarding this putative signal is that it reflects a form of probabilistic inference through sampling. Here we show that the key features of neural variability can be accounted for in a completely deterministic network model through self-organization. As the network learns a model of its sensory inputs, the deterministic dynamics give rise to sampling-like inference. Our findings show that the notorious variability in neural recordings does not need to be seen as evidence for a noisy brain. Instead it may reflect sampling-like inference emerging from a self-organized learning process.
The administration of intravenous fluid to critically ill patients is one of the most common but also one of the most fiercely debated interventions in intensive care medicine. During the past decade, a number of important studies have been published which provide clinicians with improved knowledge regarding the timing, the type and the amount of fluid they should give to their critically ill patients. However, despite the fact that many thousands of patients have been enrolled in these trials of alternative fluid strategies, consensus remains elusive and practice is widely variable. Early adequate resuscitation of patients in shock followed by a restrictive strategy may be associated with better outcomes. Colloids such as modern hydroxyethyl starch are more effective than crystalloids in early resuscitation of patients in shock, and are safe when administered during surgery. However, these colloids may not be beneficial later in the course of intensive care treatment and should best be avoided in intensive care patients who have a high risk of developing acute kidney injury. Albumin has no clear benefit over saline and is associated with increased mortality in neurotrauma patients. Balanced fluids reduce the risk of hyperchloraemic acidosis and possibly kidney injury. The use of hypertonic fluids in patients with sepsis and acute lung injury warrants further investigation and should be considered experimental at this stage. Fluid therapy impacts relevant patient-related outcomes. Clinicians should adopt an individualized strategy based on the clinical scenario and best available evidence. One size does not fit all.
The primary objective of What on Earth is a Ruling Party in a Multiparty Democracy? is to provoke thought and thereby stimulate debate. To this end, provocatively, this collection of topical issues ranges from 'The place of the miniskirt in sociocultural development' to 'Which citizen in Zambia should not take part in (partisan) politics?' The Author, Mubanga E Kashoki, is a Professor of African Languages at the institute of Economic and Social Research in the University of Zambia.
What happened in Cyprus? The economic consequences of the last communist government in Europe
(2014)
This paper reviews developments in the Cypriot economy following the introduction of the euro on 1 January 2008 and leading to the economic collapse of the island five years later. The main cause of the collapse is identified with the election of a communist government in February 2008, within two months of the introduction of the euro, and its subsequent choices for action and inaction on economic policy matters. The government allowed a rapid deterioration of public finances, and despite repeated warnings, damaged the country's creditworthiness and lost market access in May 2011. The destruction of the island's largest power station in July 2011 subsequently threw the economy into recession. Together with the intensification of the euro area crisis in the summer and fall of 2011, these events weakened the banking system which was vulnerable due to its exposure in Greece. Rather than deal with its fiscal crisis, the government secured a loan from the Russian government that allowed it to postpone action until after the February 2013 election. Rather than protect the banking system, losses were imposed on banks and a campaign against them was coordinated and used as a platform by the communist party for the February 2013 election. The strategy succeeded in delaying resolution of the crisis and avoiding short-term political cost for the communist party before the election, but also in precipitating a catastrophe right after the election.
On 23 July 2014, the U.S. Securities and Exchange Commission (SEC) passed the “Money Market Reform: Amendments to Form PF ,” designed to prevent investor runs on money market mutual funds such as those experienced in institutional prime funds following the bankruptcy of Lehman Brothers. The present article evaluates the reform choices in the U.S. and draws conclusions for the proposed EU regulation of money market funds.
Research results confirm the existence of various forms of international tax planning by multinational firms. Prominent examples for firms employing tax avoidance strategies are Amazon, Google and Starbucks. Increasing availability of administrative data for Europe has enabled researchers to study behavioural responses of European multinationals to taxation. The present paper summarizes what we can learn from these recent studies in general and about German multinationals in particular.
BACKGROUND: Micro-RNAs (miRNA) are attributed to the systems biological role of a regulatory mechanism of the expression of protein coding genes. Research has identified miRNAs dysregulations in several but distinct pathophysiological processes, which hints at distinct systems-biology functions of miRNAs. The present analysis approached the role of miRNAs from a genomics perspective and assessed the biological roles of 2954 genes and 788 human miRNAs, which can be considered to interact, based on empirical evidence and computational predictions of miRNA versus gene interactions.
RESULTS: From a genomics perspective, the biological processes in which the genes that are influenced by miRNAs are involved comprise of six major topics comprising biological regulation, cellular metabolism, information processing, development, gene expression and tissue homeostasis. The usage of this knowledge as a guidance for further research is sketched for two genetically defined functional areas: cell death and gene expression. Results suggest that the latter points to a fundamental role of miRNAs consisting of hyper-regulation of gene expression, i.e., the control of the expression of such genes which control specifically the expression of genes.
CONCLUSIONS: Laboratory research identified contributions of miRNA regulation to several distinct biological processes. The present analysis transferred this knowledge to a systems-biology level. A comprehensible and precise description of the biological processes in which the genes that are influenced by miRNAs are notably involved could be made. This knowledge can be employed to guide future research concerning the biological role of miRNA (dys-) regulations. The analysis also suggests that miRNAs especially control the expression of genes that control the expression of genes.
We use data from the 2009 Internet Survey of the Health and Retirement Study to examine the consumption impact of wealth shocks and unemployment during the Great Recession in the US. We find that many households experienced large capital losses in housing and in their financial portfolios, and that a non-trivial fraction of respondents have lost their job. As a consequence of these shocks, many households reduced substantially their expenditures. We estimate that the marginal propensities to consume with respect to housing and financial wealth are 1 and 3.3 percentage points, respectively. In addition, those who became unemployed reduced spending by 10 percent. We also distinguish the effect of perceived transitory and permanent wealth shocks, splitting the sample between households who think that the stock market is likely to recover in a year’s time, and those who do not. In line with the predictions of standard models of intertemporal choice, we find that the latter group adjusted much more than the former its spending in response to financial wealth shocks.
Part IV of our series "Cyberpeace: Dimensionen eines Gegenentwurfs" on cyberpeace. Matthias Schulze argues that what some perceive as cyberwar is not actually war but rather cyber conflict. The question therefore arises if this conflict will ever be solved. Ben Kamis on the other hand identifies motives in the use of language. He argues that talking about cyberpeace reinforces the impression that we are right in the middle of a cyberwar. I would not agree with that. As Johan Galtung puts it: “The use of the term ‘peace’ may in itself be peace-productive” (Galtung 1969: 167). But how do we define cyberpeace? Who should define it and how do we pursue it?...
Water footprints have been proposed as sustainability indicators, relating the consumption of goods like food to the amount of water necessary for their production and the impacts of that water use in the source regions. We further developed the existing water footprint methodology, by globally resolving virtual water flows from production to consumption regions for major food crops at 5 arcmin spatial resolution. We distinguished domestic and international flows, and assessed local impacts of export production. Applying this method to three exemplary cities, Berlin, Delhi and Lagos, we find major differences in amounts, composition, and origin of green and blue virtual water imports, due to differences in diets, trade integration and crop water productivities in the source regions. While almost all of Delhi's and Lagos' virtual water imports are of domestic origin, Berlin on average imports from more than 4000 km distance, in particular soy (livestock feed), coffee and cocoa. While 42% of Delhi's virtual water imports are blue water based, the fractions for Berlin and Lagos are 2 and 0.5%, respectively, roughly equal to the water volumes abstracted in these two cities for domestic water use. Some of the external source regions of Berlin's virtual water imports appear to be critically water scarce and/or food insecure. However, for deriving recommendations on sustainable consumption and trade, further analysis of context-specific costs and benefits associated with export production will be required.