Essential Fish Habitat project status report

: Groundfish that associate with rugged seafloor types are difficult to assess with bottom-trawl sampling gear. Simrad ME70 multibeam echosounder (MBES) data and video imagery were collected to characterize trawlable and untrawlable areas, and to ultimately improve efforts to determine habitat-specific groundfish biomass. The data were collected during two acoustic-trawl surveys of the Gulf of Alaska (GOA) during 2011 and 2012 by NOAA Alaska Fisheries Science Center (AFSC) researchers. MBES data were collected continuously along the trackline, which included parallel transects (1-20 nmi spacing) and fine-scale survey locations in 2011. Video data were collected at camera stations using a drop camera system. Multibeamderived seafloor metrics were overlaid with the locations of previously conducted AFSC bottomtrawl (BT) survey hauls and 2011 camera stations. Generalized linear models were used to identify the best combination of multibeam metrics to discriminate between trawlable and untrawlable seafloor for the region of overlap between the camera stations or haul paths and the MBES data. The most discriminatory models were chosen based on the Akaike information criterion (AIC). The two best models were developed using data collected at camera stations with either oblique incidence backscatter strength (Sb) or mosaic Sb in combination with bathymetric position index and seafloor ruggedness and described over 54% of the variation between trawlable and untrawlable seafloor types. A map of predicted seafloor trawlability produced from the model using mosaic Sb and benthic-terrain metrics demonstrated that 58% of the area mapped (5,987 km2 ) had \u3e 50% probability of being trawlable and 42% of being untrawlable. The model predicted 69% of trawlable and untrawlable haul locations correctly. Successful hauls occurred in areas with 62% probability of being trawlable and haul locations with gear damage occurred in areas with a 38% probability of being trawlable. This model and map produced from multibeamderived seafloor metrics may be used to refine seafloor interpretation for the AFSC BT surveys and to advance efforts to develop habitat-specific biomass estimates for GOA groundfish populations

Review Essay—Battle on the Potomac

This War Really Matters: Inside the Fight for Defense Dollar

Conservation of structure and mechanism in primary and secondary transporters exemplified by SiaP, a sialic acid binding virulence factor from Haemophilus influenzae

Extracytoplasmic solute receptors (ESRs) are important components of solute uptake systems in bacteria, having been studied extensively as parts of ATP binding cassette transporters. Herein we report the first crystal structure of an ESR protein from a functionally characterized electrochemical ion gradient-dependent secondary transporter. This protein, SiaP, forms part of a tripartite ATP-independent periplasmic transporter specific for sialic acid in Haemophilus influenzae. Surprisingly, the structure reveals an overall topology similar to ATP binding cassette ESR proteins, which is not apparent from the sequence, demonstrating that primary and secondary transporters can share a common structural component. The structure of SiaP in the presence of the sialic acid analogue 2,3-didehydro-2-deoxyN-acetylneuraminic acid reveals the ligand bound in a deep cavity with its carboxylate group forming a salt bridge with a highly conserved Arg residue. Sialic acid binding, which obeys simple bimolecular association kinetics as determined by stopped-flow fluorescence spectroscopy, is accompanied by domain closure about a hinge region and the kinking of an alpha-helix hinge component. The structure provides insight into the evolution, mechanism, and substrate specificity of ESR-dependent secondary transporters that are widespread in prokaryotes

Exploiting Human Memory B Cell Heterogeneity for Improved Vaccine Efficacy

The major goal in vaccination is establishment of long-term, prophylactic humoral memory to a pathogen. Two major components to long-lived humoral memory are plasma cells for the production of specific immunoglobulin and memory B cells that survey for their specific antigen in the periphery for later affinity maturation, proliferation, and differentiation. The study of human B cell memory has been aided by the discovery of a general marker for B cell memory, expression of CD27; however, new data suggests the existence of CD27− memory B cells as well. These recently described non-canonical memory populations have increasingly pointed to the heterogeneity of the memory compartment. The novel B memory subsets in humans appear to have unique origins, localization, and functions compared to what was considered to be a “classical” memory B cell. In this article, we review the known B cell memory subsets, the establishment of B cell memory in vaccination and infection, and how understanding these newly described subsets can inform vaccine design and disease treatment

Quenching Effects in the Hadron Spectrum

Lattice QCD has generated a wealth of data in hadronic physics over the last two decades. Until relatively recently, most of this information has been within the "quenched approximation" where virtual quark--anti-quark pairs are neglected. This review presents a descriptive discussion of the effects of removing this approximation in the calculation of hadronic masses.Comment: To appear in "Lattice Hadron Physics", ed. A.C. Kalloniatis, D.B. Leinweber and A.G. William

Lensing Magnification: A novel method to weigh high-redshift clusters and its application to SpARCS

We introduce a novel method to measure the masses of galaxy clusters at high redshift selected from optical and IR Spitzer data via the red-sequence technique. Lyman-break galaxies are used as a well understood, high-redshift background sample allowing mass measurements of lenses at unprecedented high redshifts using weak lensing magnification. By stacking a significant number of clusters at different redshifts with average masses of ~1-3x10^14M_sun, as estimated from their richness, we can calibrate the normalisation of the mass-richness relation. With the current data set (area: 6 deg^2) we detect a magnification signal at the >3-sigma level. There is good agreement between the masses estimated from the richness of the clusters and the average masses estimated from magnification, albeit with large uncertainties. We perform tests that suggest the absence of strong systematic effects and support the robustness of the measurement. This method - when applied to larger data sets in the future - will yield an accurate calibration of the mass-observable relations at z>~1 which will represent an invaluable input for cosmological studies using the galaxy cluster mass function and astrophysical studies of cluster formation. Furthermore this method will probably be the least expensive way to measure masses of large numbers of z>1 clusters detected in future IR-imaging surveys.Comment: 5 pages, 1 figure, 1 table, accepted by ApJL, minor revision