Winter distribution and size structure of Antarctic krill Euphausia superba populations in-shore along the West Antarctic Peninsula

Antarctic krill Euphausia superba are a key component of food webs in the maritime West Antarctic Peninsula, and their life history is tied to the seasonal cycles of sea ice and primary production in the region. Previous work has shown a general in-shore migration of krill in winter in this region; however, the very near-shore has not often been sampled as part of these surveys. We investigated distribution, abundance, and size structure of krill in 3 fjordic bays along the peninsula, and in the adjacent Gerlache Strait area using vertically stratified MOCNESS net tows and ADCP acoustic biomass estimates. Krill abundance was high within bays, with net estimated densities exceeding 60 krill m-3, while acoustic estimates were an order of magnitude higher. Krill within bays were larger than krill in the Gerlache Strait. Within bays, krill aggregations were observed near the seafloor during the day with aggregations extending to the sediment interface, and exhibited diel vertical migration higher into the water column at night. We suggest these high winter krill abundances within fjords are indicative of an active seasonal migration by krill in the peninsula region. Potential drivers for such a migration include reduced advective losses and costs, and availability of sediment food resources within fjords. Seasonally near-shore krill may also affect stock and recruitment assessments and may have implications for managing the krill fishery in this area

A population-specific reference panel empowers genetic studies of Anabaptist populations

Genotype imputation is a powerful strategy for achieving the large sample sizes required for identification of variants underlying complex phenotypes, but imputation of rare variants remains problematic. Genetically isolated populations offer one solution, however population-specific reference panels are needed to assure optimal imputation accuracy and allele frequency estimation. Here we report the Anabaptist Genome Reference Panel (AGRP), the first whole-genome catalogue of variants and phased haplotypes in people of Amish and Mennonite ancestry. Based on high-depth whole-genome sequence (WGS) from 265 individuals, the AGRP contains >12 M high-confidence single nucleotide variants and short indels, of which ~12.5% are novel. These Anabaptist-specific variants were more deleterious than variants with comparable frequencies observed in the 1000 Genomes panel. About 43,000 variants showed enriched allele frequencies in AGRP, consistent with drift. When combined with the 1000 Genomes Project reference panel, the AGRP substantially improved imputation, especially for rarer variants. The AGRP is freely available to researchers through an imputation server

Gut evacuation rate and grazing impact of the krill Thysanoessa raschii and T. inermis

Gut evacuation rates and ingestion rates were measured for the krill Thysanoessa raschii and T. inermis in Godthåbsfjord, SW Greenland. Combined with biomass of the krill community, the grazing potential on phytoplankton along the fjord was estimated. Gut evacuation rates were 3.9 and 2.3 h−1 for T. raschii and T. inermis, respectively. Ingestion rates were 12.2 ± 7.5 µg C mg C−1 day−1 (n = 4) for T. inermis and 4.9 ± 3.2 µg C mg C−1 day−1 (n = 4) for T. raschii, corresponding to daily rations of 1.2 and 0.5 % body carbon day−1. Clearance experiments conducted in parallel to the gut evacuation experiment gave similar results for ingestion rates and daily rations. Krill biomass was highest in the central part of the fjord’s length, with T. raschii dominating. Community grazing rates from krill and copepods were comparable; however, their combined impact was low, estimated as <1 % of phytoplankton standing stock being removed per day during this late spring study

Measuring productivity and efficiency: a Kalman filter approach

In the Kalman filter setting, one can model the inefficiency term of the standard stochastic frontier composed error as an unobserved state. In this study a panel data version of the local level model is used for estimating time-varying efficiencies of firms. We apply the Kalman filter to estimate average efficiencies of U.S. airlines and find that the technical efficiency of these carriers did not improve during the period 1999-2009. During this period the industry incurred substantial losses, and the efficiency gains from reorganized networks, code-sharing arrangements, and other best business practices apparently had already been realized

A survey of health professions students for knowledge, attitudes, and confidence about tuberculosis, 2005

<p>Abstract</p> <p>Background</p> <p>In 2003 the NIH perceived a need to strengthen teaching about tuberculosis (TB) to health professions students. The National Tuberculosis Curriculum Consortium (NTCC) was funded to meet this need. The purpose of this study was to survey students enrolled in NTCC schools prior to NTCC-developed educational materials being made available to faculty.</p> <p>Methods</p> <p>A self-administered survey for students in NTCC schools to establish a baseline level of knowledge, attitudes, and confidence about tuberculosis.</p> <p>Results</p> <p>1480/2965 (50%) students in 28 programs in 20 NTCC schools completed the survey. If public health students are eliminated from totals (only 61 respondents of 765 public health students), the overall response proportion for the seven clinically-related disciplines was 64.5%. The majority (74%) were in schools of medicine (MD/DO), undergraduate nursing (BSN), and pharmacy (PharmD); others were in programs for physician assistants (PA), advanced practice nursing (NP/APN), respiratory therapy (RT), clinical laboratory sciences (MT/CLS), and public health (MPH). Almost 90% had attended at least one lecture about TB. Although 91.4% knew TB was transmitted via aerosols, about one-third did not know the method for administering tuberculin, or that Bacillus Calmette-Guerin (BCG) vaccine was not a contraindication to TB skin testing. Fewer than two-thirds knew that about 10% of people in the U.S.A. who have latent tuberculosis infection (LTBI) and a normal immune system will develop TB disease, or that BCG is not part of the routine vaccination program in the U.S.A. because it complicates surveillance for new TB infection.</p> <p>Conclusion</p> <p>There is room for improvement in knowledge, attitudes, and confidence about TB by health professions students surveyed. The NTCC-developed educational products may be used by faculty to improve student performance to be assessed with future surveys.</p

The Role of AGG Interruptions in the Transcription of FMR1 Premutation Alleles

Fragile X associated disorders are caused by a premutation allele in the fragile X mental retardation 1 gene (FMR1) and are hypothesized to result from the toxic effect of elevated levels of expanded FMR1 transcripts. Increased levels of FMR1 mRNA have indeed been reported in premutation carriers; however the mechanism by which expanded alleles lead to elevated levels of FMR1 mRNA in premutation carriers is unknown. Within the CGG repeat tract AGG interruptions are found, generally 1–3 present in normal/intermediate alleles (6–54 CGG repeats) and usually 0–1 in premutation alleles (55–200 CGG repeats). They are present at specific locations, generally occurring after 9 or 10 uninterrupted CGG repeats [(CGG)9AGG(CGG)9AGG(CGG)n]. We evaluated both the number of AGG interruptions and the resulting length of the uninterrupted 3′ CGG repeat pure tract in premutation alleles derived from two large cohorts of male and female carriers to determine whether the presence of AGG interruptions or the length of a pure stretch of CGG repeats influence the levels of FMR1 mRNA in blood. Our findings indicate that neither the number of AGG interruptions, nor their position along the CGG tract have a significant affect on mRNA levels in premutation carriers. We also, as expected based on previous findings, observed a highly significant correlation between CGG repeat number (as both total length and length of pure CGG stretch) and FMR1 mRNA expression levels, in both males and females. Importantly, we did not observe any significant difference in FMR1 mRNA levels in premutation carriers based on age

Precise Thermal NDE for Quantifying Structural Damage

We have developed precise thermal NDE as a wide-area inspection tool to quantify structural damage within airframes and bridge decks. We used infrared cameras and image processing to produce precise temperature, thermal inertia, and cooling-rate maps of flash-heated aircraft skins. These maps allowed us to distinguish major structural defects from minor flaws which do not warrant costly repairs. We quantified aircraft skin corrosion defects with metal losses as low as 5% with 3% overall uncertainty [1–6]. We proved the feasibility of precise thermal NDE to inspect naturally-heated asphalt-concrete bridge decks. To this end, we quantified structural damage within asphalt-concrete slabs by locating the sites, and determining the relative volumes, of concrete displacements from 2-inch deep and 4-inch deep synthetic delaminations in asphalt-concrete slabs [4–8]

Conditional Stat1 Ablation Reveals the Importance of Interferon Signaling for Immunity to Listeria monocytogenes Infection

Signal transducer and activator of transcription 1 (Stat1) is a key player in responses to interferons (IFN). Mutations of Stat1 cause severe immune deficiencies in humans and mice. Here we investigate the importance of Stat1 signaling for the innate and secondary immune response to the intracellular bacterial pathogen Listeria monocytogenes (Lm). Cell type-restricted ablation of the Stat1 gene in naïve animals revealed unique roles in three cell types: macrophage Stat1 signaling protected against lethal Lm infection, whereas Stat1 ablation in dendritic cells (DC) did not affect survival. T lymphocyte Stat1 reduced survival. Type I IFN (IFN-I) signaling in T lymphocytes reportedly weakens innate resistance to Lm. Surprisingly, the effect of Stat1 signaling was much more pronounced, indicating a contribution of Stat1 to pathways other than the IFN-I pathway. In stark contrast, Stat1 activity in both DC and T cells contributed positively to secondary immune responses against Lm in immunized animals, while macrophage Stat1 was dispensable. Our findings provide the first genetic evidence that Stat1 signaling in different cell types produces antagonistic effects on innate protection against Lm that are obscured in mice with complete Stat1 deficiency. They further demonstrate a drastic change in the cell type-dependent Stat1 requirement for memory responses to Lm infection

A Dynamic Landscape for Antibody Binding Modulates Antibody-Mediated Neutralization of West Nile Virus

Neutralizing antibodies are a significant component of the host's protective response against flavivirus infection. Neutralization of flaviviruses occurs when individual virions are engaged by antibodies with a stoichiometry that exceeds a required threshold. From this “multiple-hit” perspective, the neutralizing activity of antibodies is governed by the affinity with which it binds its epitope and the number of times this determinant is displayed on the surface of the virion. In this study, we investigated time-dependent changes in the fate of West Nile virus (WNV) decorated with antibody in solution. Experiments with the well-characterized neutralizing monoclonal antibody (MAb) E16 revealed a significant increase in neutralization activity over time that could not be explained by the kinetics of antibody binding, virion aggregation, or the action of complement. Additional kinetic experiments using the fusion-loop specific MAb E53, which has limited neutralizing activity because it recognizes a relatively inaccessible epitope on mature virions, identified a role of virus “breathing” in regulating neutralization activity. Remarkably, MAb E53 neutralized mature WNV in a time- and temperature-dependent manner. This phenomenon was confirmed in studies with a large panel of MAbs specific for epitopes in each domain of the WNV envelope protein, with sera from recipients of a live attenuated WNV vaccine, and in experiments with dengue virus. Given enough time, significant inhibition of infection was observed even for antibodies with very limited, or no neutralizing activity in standard neutralization assays. Together, our data suggests that the structural dynamics of flaviviruses impacts antibody-mediated neutralization via exposure of otherwise inaccessible epitopes, allowing for antibodies to dock on the virion with a stoichiometry sufficient for neutralization