Polarization Limits in K-Rb Spin-Exchange Mixtures

We present measurements of the optical absorption of K vapor at 795 nm due to the presence of high pressure He gas. The results set a limit on the polarization attainable in hybrid spin-exchange optical pumping of He-3

Massive photons: an infrared regularization scheme for lattice QCD+QED

Standard methods for including electromagnetic interactions in lattice quantum chromodynamics calculations result in power-law finite-volume corrections to physical quantities. Removing these by extrapolation requires costly computations at multiple volumes. We introduce a photon mass to alternatively regulate the infrared, and rely on effective field theory to remove its unphysical effects. Electromagnetic modifications to the hadron spectrum are reliably estimated with a precision and cost comparable to conventional approaches that utilize multiple larger volumes. A significant overall cost advantage emerges when accounting for ensemble generation. The proposed method may benefit lattice calculations involving multiple charged hadrons, as well as quantum many-body computations with long-range Coulomb interactions.Comment: 6 pages, 4 figures, 2 tables; significant revisions to abstract and main text; revised presentation of results for clarity (results unchanged); acknowledgements updated; matches published versio

Hypoxia does not influence the response of fish to a mixture of estrogenic chemicals

The official published version can be obtained from the link below - Copyright @ 2009 American Chemical SocietyChemical risk assessment procedures assign a major role to standardized toxicity tests, in which the response of a particular organism to a single test substance is determined under otherwise constant and favorable conditions in the laboratory. This approach fails to consider the potential for chemical interactions, as well as failing to consider how the toxicological response varies, depending on the conditions of exposure. As yet, the issue of confounding factors on chemically mediated effects in wildlife has received little attention, despite the fact that a range of physicochemical parameters, including temperature, water quality, and pH, are known to modify chemical toxicity. Here, we consider how the estrogenic response of fish varies with regard to hypoxia. Fathead minnows (Pimephales promelas) were exposed to a mixture of estrogenic chemicals under hypoxic or normoxic conditions. Their estrogenic response was characterized using an in vivo assay, involving the analysis of the egg yolk protein, vitellogenin (VTG). The results revealed that there was no effect of hypoxia on the VTG response in either treatment group at the end of the exposure period. This suggests that this end point is robust and relatively insensitive to the effects of any physiological changes that arise as a result of hypoxia. The implications of these negative findings are discussed in terms of their relevance with regard to the development of risk assessment policy.This work was funded by a grant from the Natural Environment Research Council(NE/D00389X/1)

Regional genetic structure in the Magellanic penguin (Spheniscus magellanicus) suggests metapopulation dynamics

Using microsatellite markers and mitochondrial DNA (mtDNA) sequences (cytochrome oxidase 1 gene), we estimated levels of genetic structuring among nine Magellanic Penguin (Spheniscus magellanicus) colonies distributed throughout three major reproductive regions of the South Atlantic Ocean. Overall, breeding colonies showed relatively high levels of genetic diversity at both nuclear and mtDNA markers (mean heteorzygosity: He = 0.598; mean allelic diversity: A = 7.11; mtDNA haplotype diversity: h = 0.812). A hierarchical analysis of molecular variance based on microsatellite data showed limited genetic structuring of breeding colonies, with 99% of the variation explained by differences among individuals and 0.7–1.0% attributed to differences among the three regions. The mtDNA analysis revealed higher levels of genetic structuring, with 3.43% of the variation explained by regions and 2.24% explained by colonies within the regions. Furthermore, a Mantel test revealed a significant association between geographic and genetic distances among colonies. The limited genetic structuring we detected is likely a result of (1) population intermixing through natal dispersal and (2) the large effective sizes of the reproductive colonies, both of which prevent genetic differentiation at neutral markers, balanced with (3) the regional association of breeding colonies to distinct feeding grounds and (4) a recent expansion of the population. Our results suggest that the demographic dynamics of breeding colonies of Magellanic Penguins may be framed under a metapopulation model, in which colonies with large numbers of breeding pairs could be considered source populations for maintaining the overall abundance of this species in the Atlantic Ocean

Physiological condition in Magellanic Penguins: Does it matter if you have to walk a long way to your nest?

Colony edges, as opposed to interiors, are often considered less advantageous nesting places in colonial species. For temperate-breeding penguins, inland colony edges should be less desirable than other edges, as there are added costs of walking farther inland, and ambient temperatures are higher. During settlement and incubation, we compared body condition and baseline and stress-induced levels of the hormone corticosterone in male Magellanic Penguins (Spheniscus magellanicus) nesting on the sea edge of a colony with those nesting on the inland edge, \u3e800 m from shore. Body condition in both groups was significantly lower during settlement than during incubation, but was similar in both groups within breeding stages. Corticosterone levels were similar between breeding stages and for groups within each breeding stage. While body condition can vary over time, penguins appear to be well buffered to physiological extremes, as they do not show modification of corticosterone levels with variations in nesting conditions

Age and food deprivation affects expression of the glucocorticosteriod stress response in Magellanic penguin (Spheniscus magellanicus) chicks

We examined how the glucocortical stress response in free‐living Magellanic penguin (Spheniscus magellanicus) chicks changes with age and whether adrenocortical function of chicks within a brood varies in relation to food provisioned by adults. Chicks showed little corticosterone response to capture stress shortly after hatching, an intermediate response around 45‐d posthatch, and a robust stress response near fledging. However, in response to an adrenocorticotropic hormone (ACTH) challenge, hatchlings were capable of secreting corticosterone at adult‐like levels. The larger sibling in broods of two showed a similar gradual stress‐response development pattern. In contrast, by day 45, when differences in body condition were well established between siblings, the smaller, food‐deprived chicks significantly increased baseline levels of corticosterone but showed normal stress‐induced levels. Near fledging, baseline levels had returned to normal, but stress‐induced levels were lower than expected. Similar to altricial species, normally developing semialtricial Magellanic penguin chicks do not express a robust corticosterone stress response until near fledging. Chronic stressors such as food deprivation cause corticosterone use to be up‐regulated earlier than expected. However, in cases of extended chronic stress, down‐regulation may ensue, thus avoiding the negative effects of chronically elevated levels of corticosterone

Coral Reef Conservation Program (CRCP) Local Action Strategy (LAS) Project 3B “Southeast Florida Coral Reef Fishery-Independent Baseline Assessment” – 2012-2013 Interim Report

Reef fishes are important biologic, ecologic, and economic resources of the marine ecosystem which must be managed for sustainability. Until recently there was no long-term monitoring program in place to assess the condition of fish resources of the northern Florida Reef Tract (FRT) (northern Miami-Dade, Broward, Palm Beach, and Martin counties). An assessment/monitoring plan for the northern Florida reef tract was designed through a joint cooperative effort by scientists at the University of Miami Rosenstiel School of Marine and Atmospheric Science, NOAA-Southeast Fisheries Science Center and Nova Southeastern University Oceanographic Center (NSUOC). This report is a synoptic compilation of the two-year data collection from all partner agencies, and includes data from the 234 and 354 sites or Primary Sampling Units (PSUs) sampled in 2012 and 2013, respectively. The majority of the field work was accomplished through funding granted to NSUOC. Significant amounts of data were also collected by multiple partner agencies that were able to dedicate their time and resources to the project. In 2012 funding for the first year of data collection was awarded by Florida Department of Environmental Protection (FDEP) to NSUOC on July 1st, 2012. Funding for a second year of sampling was awarded by National Oceanic and Atmospheric Administration (NOAA) Coral Reef Conservation Program (CRCP) to NSUOC through the National Coral Reef Institute Cooperative Agreement on June 18, 2013. Field sampling for each year began in May and ran through October. Funding for a third year of data collection (2014) and a final report was awarded by NOAA CRCP to NSUOC. Over the course of the two-year study period for this interim report, \u3e170,000 individual fish of 266 species were recorded. Total mean density for all sites and strata combined for both years was 162 fishes/SSU. For 2012, mean density was 151 fishes/SSU; in 2013 it was 168 fishes/SSU. However, in general, 2012 counts were higher at most sites. When low vs. high slope strata were compared, the high slope strata showed higher fish density. Likewise, species richness was higher at most sites in 2012 than 2013 and was also significantly higher for both years on sites with high slope. Multivariate analyses showed patterns in the reef fish communities associated with benthic habitats. Water depth was a primary determinant of fish distribution with differences in assemblages between shallow and deep sites. Also most of the surveys in the southern regions (Broward-Miami, Deerfield, and South Palm Beach) clustered tightly together indicating high similarity between communities in the deep habitats within these regions. Conversely, fish communities in North Palm Beach and Martin were much more variable and mostly separated in disparate areas of the plot. This suggests that the Martin and North Palm Beach fish communities are distinctly different from the southern regions. The dataset, in its entirety, provides the opportunity for further mining to examine individual species and reef fish assemblage correlations with a host of abiotic and biotic variables. Thus, from both management and ecological-sciences perspectives, it is a valuable resource. It is already clear there are significant differences in the geographic distribution of reef fishes at local and regional scales. There are interacting strata and latitudinal differences in total reef fish abundance, species distribution, sizes, and assemblage structure. The combination of data from all three years will provide a complete regional baseline fishery-independent assessment

Southeast Florida Coral Reef Fishery-Independent Baseline Assessment

Reef fishes are important biologic, ecologic, and economic resources of the marine ecosystem which must be managed for sustainability. Until recently, there was no long-term monitoring program in place to assess the condition of reef fish resources of the northern Florida Reef Tract (FRT) (northern Miami-Dade, Broward, Palm Beach, and Martin counties). An assessment/monitoring plan for the northern portion of the Florida reef tract was designed through a joint cooperative effort by scientists at the University of Miami, Rosenstiel School of Marine and Atmospheric Science (RSMAS), National Oceanic and Atmospheric Administration (NOAA)-Southeast Fisheries Science Center (SEFSC) and Nova Southeastern University Oceanographic Center (NSUOC). This report is a synoptic compilation of a three-year data collection from all partner agencies, and includes data from the 232, 324, and 308 sites or Primary Sampling Units (PSUs) sampled in 2012, 2013, and 2014, respectively. The majority of the field work was accomplished through funding provided to NSUOC by the NOAA Coral Reef Conservation Program (CRCP), with supplementary funding provided by FDEP-CRCP. Significant amounts of data were also collected by multiple Southeast Florida Coral Reef Initiative (SEFCRI) partner agencies that were able to dedicate their time and resources to the project. Field sampling for each year began in May and ran through October. During the three-year study period, \u3e560,000 individual fish of 289 species were recorded. Total mean density for all sites and strata combined for all three years was 170 fishes/SSU (Second-Stage Sample Unit = SSU or site, 177 m2). For 2012, mean density was 151 fishes/SSU; in 2013 it was 168 fishes/SSU; and in 2014 it was 186 fishes/SSU. When low vs. high slope strata were compared, the high slope strata showed higher fish density. Multivariate analyses showed patterns in the reef fish communities associated with benthic habitats. Water depth was a primary determinant of fish distribution with differences in assemblages between shallow and deep sites. Also most of the surveys in the southern regions (Broward-Miami, Deerfield, and South Palm Beach) clustered tightly together indicating high similarity between communities in the deep habitats within these regions. Conversely, fish communities in North Palm Beach and Martin were much more variable and mostly separated in disparate areas of the plot. This suggests that the Martin and North Palm Beach fish communities are distinctly different from the southern regions. The dataset, in its entirety, provides the opportunity for further mining to examine individual species and reef fish assemblage correlations with a host of abiotic and biotic variables. Thus, from both management and ecological-sciences perspectives, these data are a valuable resource. It is already clear there are significant differences in the geographic distribution of reef fishes at local and regional scales. There are interacting strata and latitudinal differences in total reef fish abundance, species distribution, sizes, and assemblage structure. The combination of data from all three years provides a complete regional baseline fishery-independent assessment

A Selective Irreversible Inhibitor of Furin Does Not Prevent Pseudomonas Aeruginosa Exotoxin A-Induced Airway Epithelial Cytotoxicity

Many bacterial and viral pathogens (or their toxins), including Pseudomonas aeruginosa exotoxin A, require processing by host pro-protein convertases such as furin to cause disease. We report the development of a novel irreversible inhibitor of furin (QUB-F1) consisting of a diphenyl phosphonate electrophilic warhead coupled with a substrate-like peptide (RVKR), that also includes a biotin tag, to facilitate activity-based profiling/visualisation. QUB-F1 displays greater selectivity for furin, in comparison to a widely used exemplar compound (furin I) which has a chloromethylketone warhead coupled to RVKR, when tested against the serine trypsin-like proteases (trypsin, prostasin and matriptase), factor Xa and the cysteine protease cathepsin B. We demonstrate QUB-F1 does not prevent P. aeruginosa exotoxin A-induced airway epithelial cell toxicity; in contrast to furin I, despite inhibiting cell surface furin-like activity to a similar degree. This finding indicates additional proteases, which are sensitive to the more broad-spectrum furin I compound, may be involved in this process

Enhancing the social issues components in our computing curriculum: Computing for the social good

The acceptance and integration of social issues into computing curricula is still a work in progress twenty years after it was first incorporated into the ACM Computing Curricula. Through an international survey of computing instructors, this paper corroborates prior work showing that most institutions include the societal impact of ICT in their programs. However, topics often concentrate on computer history, codes of ethics and intellectual property, while neglecting broader issues of societal impact. This paper explores how these neglected topics can be better developed through a subtle change of focus to the significant role that ICT plays in addressing the needs of the community. Drawing on the survey and a set of implementation cases, the paper provides guidance by means of examples and resources to empower teaching teams to engage students in the application of ICT to bring about positive social outcomes – computing for the social good