Mississippi State University

About: Mississippi State University is a education organization based out in Starkville, Mississippi, United States. It is known for research contribution in the topics: Population & Catfish. The organization has 14115 authors who have published 28594 publications receiving 700030 citations. The organization is also known as: The Mississippi State University of Agriculture and Applied Science & Mississippi State University of Agriculture and Applied Science.

Macroecology of a host-parasite relationship

Abstract: fish assemblages each significantly accounted for the regional variation in mussel assemblages. Furthermore, mussel assemblages showed strong spatial autocorrelation. Variation partitioning revealed that pure fish effects accounted for 15.4% of the variation in mussel assemblages; pure spatial and environmental effects accounted for 16.1% and 7.8%, respectively. Shared variation among fish, space and environmental variables totaled 40%. Of this shared variation, 36.8% was associated with the fish matrix. Thus, the variation in mussel assemblages that was associated with the distribution and abundance of fishes was substantial (> 50%), indicating that fish community structure is an important determinant of mussel community structure. Although animals commonly disperse plants and, thus, influence the structure of plant communities, our results show a strong macroecological association between two disparate animal groups with one strongly affecting the assemblage structure of

Evidence for global cooling in the Late Cretaceous

Abstract: The Late Cretaceous ‘greenhouse’ world witnessed a transition from one of the warmest climates of the past 140 million years to cooler conditions, yet still without significant continental ice. Low-latitude sea surface temperature (SST) records are a vital piece of evidence required to unravel the cause of Late Cretaceous cooling, but high-quality data remain illusive. Here, using an organic geochemical palaeothermometer (TEX86), we present a record of SSTs for the Campanian–Maastrichtian interval (~83–66 Ma) from hemipelagic sediments deposited on the western North Atlantic shelf. Our record reveals that the North Atlantic at 35 °N was relatively warm in the earliest Campanian, with maximum SSTs of ~35 °C, but experienced significant cooling (~7 °C) after this to <~28 °C during the Maastrichtian. The overall stratigraphic trend is remarkably similar to records of high-latitude SSTs and bottom-water temperatures, suggesting that the cooling pattern was global rather than regional and, therefore, driven predominantly by declining atmospheric pCO2 levels. The Late Cretaceous experienced significant cooling, yet a lack of low-latitude records mean the regional extent of this cooling is poorly constrained. Linnert et al. present a TEX86sea surface temperature record from a palaeolatitude of ~35 °N and show that Late Cretaceous cooling was global in nature.

Spatial variability and trends in observed snow depth over North America

Abstract: [1] This study uses a gridded dataset of daily U.S. and Canadian surface observations from 1960–2000 to study regional spatial and temporal variability and trends in snow depth across North America. Analysis shows minimal change in North American snow depth through January, with regions of decreasing snow depths beginning in late January. These regional decreases grow in intensity and extent through March and into April, implying an earlier onset of spring melt. The region showing the greatest decreases in snow depth occurs in central Canada, along a line from the Yukon Territory in northwestern Canada to the Great Lakes region. The regional decreases in spring snow depth across central Canada are likely a result of more rapid melt of shallower winter snowpacks, evident through shallower snow cover (2–10 cm) during May and October and a decrease in extent of deeper snowpacks (>40cm) through March and April.

The effects of virtual reality, augmented reality, and motion parallax on egocentric depth perception

Abstract: As the use of virtual and augmented reality applications becomes more common, the need to fully understand how observers perceive spatial relationships grows more critical. One of the key requirements in engineering a practical virtual or augmented reality system is accurately conveying depth and layout. This requirement has frequently been assessed by measuring judgments of egocentric depth. These assessments have shown that observers in virtual reality (VR) perceive virtual space as compressed relative to the real-world, resulting in systematic underestimations of egocentric depth. Previous work has indicated that similar effects may be present in augmented reality (AR) as well.This paper reports an experiment that directly measured egocentric depth perception in both VR and AR conditions; it is believed to be the first experiment to directly compare these conditions in the same experimental framework. In addition to VR and AR, two control conditions were studied: viewing real-world objects, and viewing real-world objects through a head-mounted display. Finally, the presence and absence of motion parallax was crossed with all conditions. Like many previous studies, this one found that depth perception was underestimated in VR, although the magnitude of the effect was surprisingly low. The most interesting finding was that no underestimation was observed in AR.

A novel core genome-encoded superantigen contributes to lethality of community-associated MRSA necrotizing pneumonia

Abstract: Bacterial superantigens (SAg) stimulate T-cell hyper-activation resulting in immune modulation and severe systemic illnesses such as Staphylococcus aureus toxic shock syndrome. However, all known S. aureus SAgs are encoded by mobile genetic elements and are made by only a proportion of strains. Here, we report the discovery of a novel SAg staphylococcal enterotoxin-like toxin X (SElX) encoded in the core genome of 95% of phylogenetically diverse S. aureus strains from human and animal infections, including the epidemic community-associated methicillin-resistant S. aureus (CA-MRSA) USA300 clone. SElX has a unique predicted structure characterized by a truncated SAg B-domain, but exhibits the characteristic biological activities of a SAg including Vβ-specific T-cell mitogenicity, pyrogenicity and endotoxin enhancement. In addition, SElX is expressed by clinical isolates in vitro, and during human, bovine, and ovine infections, consistent with a broad role in S. aureus infections of multiple host species. Phylogenetic analysis suggests that the selx gene was acquired horizontally by a progenitor of the S. aureus species, followed by allelic diversification by point mutation and assortative recombination resulting in at least 17 different alleles among the major pathogenic clones. Of note, SElX variants made by human- or ruminant-specific S. aureus clones demonstrated overlapping but distinct Vβ activation profiles for human and bovine lymphocytes, indicating functional diversification of SElX in different host species. Importantly, SElX made by CA-MRSA USA300 contributed to lethality in a rabbit model of necrotizing pneumonia revealing a novel virulence determinant of CA-MRSA disease pathogenesis. Taken together, we report the discovery and characterization of a unique core genome-encoded superantigen, providing new insights into the evolution of pathogenic S. aureus and the molecular basis for severe infections caused by the CA-MRSA USA300 epidemic clone.