Predicting the Viability of Fish Populations in a Modified Riverine Environment

Riverine fishes evolved to life in a highly variable, flow-driven environment. During the two past centuries, large rivers have been substantially altered by human activities. This has resulted in declines of fish populations that depend on the large river environment. The research described here uses models to evaluate the effects of human activities on the viability of fish populations in rivers. I focused on five modifications of the river environment associated with impoundment: (1) seasonal allocation of river flow; (2) diversion of river flow; (3) fragmentation of the river habitat by dams; (4) conversion of free-flowing river to reservoir habitat; and (5) alteration of migration patterns. To understand the role of flow regulation on chinook salmon (Oncorhynchus tshawytscha) recruitment, I developed an individual-based model to predict recruitment as a function of seasonal flow patterns in the Tuolumne River, California. I used simulated annealing to find flow patterns that maximize chinook recruitment under wet and dry hydrologic conditions. As water availability increased, I found that the optimal flow pattern shifted from allocating low flows uniformly across seasons to a pattern with high spring flows. When I considered a new objective: maximizing the variance of spawning times among recruits, the optimal flow regime called for a winter pulse in flow just before the peak spawning date for the minority (late-fall) run. To evaluate the recovery options for chinook salmon in the Tuolumne River, Ideveloped an age-based model to conduct a population viability analysis (PVA). I developed a flow-dependent spawner-recruitment relationship from the recruitment model. Its shape depended on the flow regime, suggesting that such relationships are not fixed properties of species, but depend on environmental conditions. The PVA model suggested that recovery, in the absence of straying, would be enhanced most by significantly reducing ocean harvest, followed by reduced diversion of water from the river. For white sturgeon (Acipenser transmontanus) populations in the Snake River, Idaho a main concern is habitat fragmentation by dams resulting in smaller, isolated populations. Simulation experiments to evaluate the effects of fragmentation suggested that population viability was higher when dams were spaced widely enough apart to retain free-flowing habitat. A simulation experiment to evaluate the effects of altered migration patterns associated with impoundment showed that both the likelihood of persistence and the genetic diversity among white sturgeon populations were enhanced by balanced upstream and downstream migration rates. Models that simulate the responses of fish populations to modified river habitat do not consider the potential for an evolutionary response. I designed a PVA model simulating the genetic basis of age at maturity for individual fish. Simulated individual variation in this trait lead to increased population viability only when the variation was heritable and subjected to an altered selective regime. The results support the idea that predicting population viability depends on estimating the potential for evolution in fitness-related traits for populations exposed to anthropogenic changes in the environment that impose strong, directional selective forces

Diagnosis and Treatment of Bradykinin-Mediated Angioedema: Outcomes from an Angioedema Expert Consensus Meeting

Several types of angioedema exist beyond hereditary angioedema (HAE) types I/II; however, the diagnostic and treatment needs of these conditions are not well understood. Noticeably, there are no licensed treatments available for other forms of angioedema beyond HAE types I/II, and similarly they are unresponsive to conventional antihistamine/glucocorticoid treatment. A group of angioedema experts met in Budapest in May 2013 to discuss such issues, presenting their experience, reviewing available literature and identifying unmet diagnostic and treatment needs in three different angioedema types: HAE with normal C1-inhibitor (C1-INH; previously referred to as type III HAE); nonallergic angiotensin-converting enzyme inhibitor (ACEI)-induced angioedema (ACEI-AAE), and acquired angioedema due to C1-INH deficiency (C1-INH-AAE). The group identified unmet diagnostic and treatment needs in HAE-nC1-INH, C1-INH-AAE and ACEI-AAE, explored remedies and made recommendations on how to diagnose and treat these forms of angioedema. The group discussed the difficulties associated with using diagnostic markers, such as the level and function of C1-INH, C1q and C4 to reliably diagnose the angioedema type, and considered the use of genetic testing to identify mutations in FXII or XPNPEP2 that have been associated with HAE-nC1-INH and ACEI-AAE, respectively. Due to the lack of approved treatments for HAE-nC1-INH, ACEI-AAE and C1-INH-AAE, the group presented several case studies in which therapies approved for treatment of HAE types I/II, such as icatibant, ecallantide and pasteurized, nanofiltered C1-INH, were successful. It was uniformly agreed that further studies are needed to improve the diagnosis and treatment of angioedema other than HAE types I/II. (c) 2014 S. Karger AG, Basel

Non-supersymmetric black rings as thermally excited supertubes

We construct a seven-parameter family of supergravity solutions that describe non-supersymmetric black rings and black tubes with three charges, three dipoles and two angular momenta. The black rings have regular horizons and non-zero temperature. They are naturally interpreted as the supergravity descriptions of thermally excited configurations of supertubes, specifically of supertubes with two charges and one dipole, and of supertubes with three charges and two dipoles. In order to fully describe thermal excitations near supersymmetry of the black supertubes with three charges and three dipoles a more general family of black ring solutions is required.Comment: 35 pages. v2: ref added and minor typo correcte

Empirical Geographic Modeling of Switchgrass Yields in the United States

Switchgrass (Panicum virgatum L.) is a perennial grass native to the United States that has been studied as a sustainable source of biomass fuel. Although many field‐scale studies have examined the potential of this grass as a bioenergy crop, these studies have not been integrated. In this study, we present an empirical model for switchgrass yield and use this model to predict yield for the conterminous United States. We added environmental covariates to assembled yield data from field trials based on geographic location. We developed empirical models based on these data. The resulting empirical models, which account for spatial autocorrelation in the field data, provide the ability to estimate yield from factors associated with climate, soils, and management for both lowland and upland varieties of switchgrass. Yields of both ecotypes showed quadratic responses to temperature, increased with precipitation and minimum winter temperature, and decreased with stand age. Only the upland ecotype showed a positive response to our index of soil wetness and only the lowland ecotype showed a positive response to fertilizer. We view this empirical modeling effort, not as an alternative to mechanistic plant‐growth modeling, but rather as a first step in the process of functional validation that will compare patterns produced by the models with those found in data. For the upland variety, the correlation between measured yields and yields predicted by empirical models was 0.62 for the training subset and 0.58 for the test subset. For the lowland variety, the correlation was 0.46 for the training subset and 0.19 for the test subset. Because considerable variation in yield remains unexplained, it will be important in the future to characterize spatial and local sources of uncertainty associated with empirical yield estimates

The influence of trigger factors on hereditary angioedema due to C1-inhibitor deficiency

Background: Hereditary angioedema (HAE) resulting from C1-inhibitor deficiency is characterized by attacks of subcutaneous and submucosal edema. Many factors have been presumed to induce edema. Our study analyzed these factors in a fairly large patient population. Methods. In the first stage of our study, we analyzed the data recorded by 92 subjects in their patient diaries over seven years. The second phase included 27 HAE patients, who had been completing the diary entry 'Trigger factors' every day for seven months whether or not they had experienced an attack. Results: During the initial stage, 91% of the subjects described some factor possibly related to the onset of an attack. They could identify a trigger factor - most commonly (21%) mental stress - in 30% of the 3176 attacks. We found a significant (p < 0.001) difference in the distribution of the trigger factors of the edematous attacks of different locations. The 27 participants of the second phase identified 882 potential trigger factors and recorded 365 attacks. Of these, 246 (67%) occurred on days when the patients identified a potential trigger factor. The likelihood of edema-formation associated with the latter was as follows: menstruation - 63%, infection - 38%, mental stress - 26%, physical exertion - 25%, meteorological changes - 21%, fatigue - 17%. Conclusion: This analysis of the trigger factors explored, for the first time, their potential role in inducing HAE attacks. Our findings might open new perspectives in extending the indications for edema-prophylaxis, and could contribute to a better understanding of the pathomechanism of HAE attacks. © 2014Zotter et al.; licensee BioMed Central Ltd

From Fake Supergravity to Superstars

The fake supergravity method is applied to 5-dimensional asymptotically AdS spacetimes containing gravity coupled to a real scalar and an abelian gauge field. The motivation is to obtain bulk solutions with R x S^3 symmetry in order to explore the AdS/CFT correspondence when the boundary gauge theory is on R x S^3. A fake supergravity action, invariant under local supersymmetry through linear order in fermion fields, is obtained. The gauge field makes things more restrictive than in previous applications of fake supergravity which allowed quite general scalar potentials. Here the superpotential must take the form W(\phi) ~ exp(-k\phi) + c exp(2\phi/(3k)), and the only freedom is the choice of the constant k. The fermion transformation rules of fake supergravity lead to fake Killing spinor equations. From their integrability conditions, we obtain first order differential equations which we solve analytically to find singular electrically charged solutions of the Lagrangian field equations. A Schwarzschild mass term can be added to produce a horizon which shields the singularity. The solutions, which include "superstars", turn out to be known in the literature. We compute their holographic parameters.Comment: 42 pages, 3 figure

Whole genome sequencing and identification of Bacillus endophyticus and B. anthracis isolated from anthrax outbreaks in South Africa

Abstract Background Bacillus endophyticus is a soil plant-endophytic bacterium, while B. anthracis is the causative agent of anthrax. The virulence factors of B. anthracis are the plasmid encoded tripartite toxins (pXO1) and poly-γ-glutamic acid (PGA) capsule (pXO2). B. endophyticus isolated alongside B. anthracis from animals that died of anthrax in Northern Cape Province (NCP), South Africa, harbored polyglutamate genes. The study compared the characteristics of B. anthracis and B. endophyticus with other Bacillus species with a focus on the presence of the PGA capsule or/and unbound PGA. The morphology and whole genome sequence analysis of B. endophyticus strains and B. anthracis were compared. Results In conventional microbiology, B. endophyticus showed gram-positive round-shaped rods in single/short chains, which were endospore-forming, non-motile, non-haemolytic with white and dry colonies, and γ-phage resistant. B. anthracis was differentiated from B. endophyticus based on the latter’s box-shaped rods in pairs/long chains, white-grey and slimy colonies, encapsulated and γ-phage susceptible. The study identified a PGA polyglutamate synthase operon that consisted of pgsBCA, γ-glutamyltranspeptidase (ggt) and pgsE in B. endophyticus genomes. Conclusions PGA regions of B. anthracis contain capBCADE genes located in the pXO2 required for capsulation formation, while B. endophyticus contain the pgsBCAE genes in the chromosome. Whole genome and microbiology analysis identified B. endophyticus, as a non-capsuled endospore-forming bacterium that consists of PGA required for biosynthesis. B. endophyticus strains do not synthesize surface associated PGA, therefore capsule visualization of B. anthracis is a key diagnostic characteristic. The study highlights the significance of using whole genome shotgun sequencing to identify virulence and other important genes that might be present amongst unknown samples from natural outbreaks. None of the B. anthracis related plasmids or virulence genes were found in the B. endophyticus genomes