Ecological Controls on the Campanian Distribution of Hesperornis (Aves: Hesperornithiformes) in the Western Interior Seaway

The epicontinental Western Interior Seaway (WIS) of Late Cretaceous North America provided a unique marine habitat for cephalopods, fish, marine reptiles, and the foot-propelled diving seabird Hesperornis. While several predator-prey relationships among Hesperornis or other hesperornithiforms and other WIS animals have been hypothesized based on gut contents, bite marks, and coprolites/colonites, ecological relationships have not been quantitatively tested. Paleontological species distribution modeling (SDM) studies have focused on extinct non-marine taxa and marine invertebrates, with only two marine vertebrate studies of extant taxa. Here, two SDM methods were used to test the influence of vertebrate faunas, sedimentary rock type, paleogeography, and outcrop area on Hesperornis occurrences: generalized linear models (GLMs) and occupancy models (an extension of standard GLMs). Results of both model types indicate a decreased probability of Hesperornis presence at elasmosaur-occupied sites and an increased probability of Hesperornis presence with higher paleolatitudes. The negative association between elasmosaurs and Hesperornis in all highest-ranked models, coupled with evidence of similar diets, may indicate food resource competition, but the geographic distributions of both taxa may instead reflect different habitat preferences. The positive impact of paleolatitude may reflect seasonal migrations resulting in large breeding congregations at higher paleolatitudes (based on probable immature specimens), preference for specific environmental conditions or feeding areas (e.g., along oceanographic fronts or upwelling zones), or migration mortality. While Spearman’s correlation test did not identify a western, middle, or eastern WIS preference for Hesperornis, the inclusion of this regional covariate with paleolatitude in the highest-ranked occupancy models may indicate an interaction effect between these two covariates that favored higher Hesperornis abundance in South Dakota and Manitoba along probable mixing zones or fronts. Taxa hypothesized by previous authors to have had ecological interactions with hesperornithiforms were not supported by the models as major factors in the Hesperornis distribution. These include Tylosaurus and polycotylid plesiosaurs, hypothesized feeders on Hesperornis, Enchodus, a teleost consumed by the smaller hesperornithiform Fumicollis, and Squalicorax, an opportunistic shark that consumed hesperornithiforms. This study represents the first paleogeographic model for Hesperornis occurrences and the first GLM and occupancy modeling applications to extinct marine vertebrates. These models examine previous hypotheses and provide novel interpretations for hesperornithiform ecology

Predicting the Distribution of the Extinct Sea Bird Hesperornis

In the Late Cretaceous, North America was divided by a shallow epicontinental sea known as the Western Interior Seaway. Native life included various marine reptiles, fish, ammonites, and seabirds such as Hesperornis . Previous research has applied ecological niche modeling to discuss competition among large vertebrates in the seaway (mosasaurs and predatory fish) but ignored small vertebrates. The present study combined localities of Hesperornis fossils with sea surface temperature estimates to characterize the distribution of Hesperornis in the upper Great Plains. Temperature interpolation in ArcGIS and niche analysis in Maxent predicted that Hesperornis preferred warmer marine waters (highest suitability values) and may support the hypothesis that Hesperornis migrated between the paleo Arctic and the lower Western Interior Seaway. Most of the study area, however, is homogenous in suitability, indicating the results are largely inconclusive. Additional ecosystem variables (e.g., biological interactions and rock type) will be applied in future analyses to describe the distribution of Hesperorni

Effects of p21 on HIV transcription

HIV represents a global health problem. The phenomenon of HIV latency presents challenges in treating and curing HIV infection. Understanding the mechanisms behind HIV latency may provide the route to cure HIV. In a subset of elite controllers, elevated levels of p21 provide resistance to HIV replication by inhibiting transcription. I attempted to understand the mechanisms by overexpressing p21 in HEK 293T cells

The first detection of the 232 GHz vibrationally excited H2O maser in Orion KL with ALMA

We investigated the ALMA science verification data of Orion KL and found a spectral signature of the vibrationally excited H2O maser line at 232.68670 GHz (nu2=1, 5,5,0-6,4,3). This line has been detected in circumstellar envelopes of late-type stars so far but not in young stellar objects including Orion KL. Thus, this is the first detection of the 232 GHz vibrationally excited H2O maser in star-forming regions. The distribution of the 232 GHz maser is concentrated at the position of the radio Source I, which is remarkably different from other molecular lines. The spectrum shows a double-peak structure at the peak velocities of -2.1 and 13.3 km s-1. It appears to be consistent with the 22 GHz H2O masers and 43 GHz SiO masers observed around Source I. Thus, the 232 GHz H2O maser around Source I would be excited by the internal heating by an embedded protostar, being associated with either the root of the outflows/jets or the circumstellar disk around Source I, as traced by the 22 GHz H2O masers or 43 GHz SiO masers, respectively.Comment: 11 pages, 4 figures, accepted for publication in ApJ

Recombinant anticoccidial vaccines - a cup half full?

Eimeria species parasites can cause the disease coccidiosis, most notably in chickens. The occurrence of coccidiosis is currently controlled through a combination of good husbandry, chemoprophylaxis and/or live parasite vaccination; however, scalable, cost-effective subunit or recombinant vaccines are required. Many antigens have been proposed for use in novel anticoccidial vaccines, supported by the capacity to reduce disease severity or parasite replication, increase body weight gain in the face of challenge or improve feed conversion under experimental conditions, but none has reached commercial development. Nonetheless, the protection against challenge induced by some antigens has been within the lower range described for the ionophores against susceptible isolates or current live vaccines prior to oocyst recycling. With such levels of efficacy it may be that combinations of anticoccidial antigens already described are sufficient for development as novel multi-valent vaccines, pending identification of optimal delivery systems. Selection of the best antigens to be included in such vaccines can be informed by knowledge defining the natural occurrence of specific antigenic diversity, with relevance to the risk of immediate vaccine breakthrough, and the rate at which parasite genomes can evolve new diversity. For Eimeria, such data are now becoming available for antigens such as apical membrane antigen 1 (AMA1) and immune mapped protein 1 (IMP1) and more are anticipated as high-capacity, high-throughput sequencing technologies become increasingly accessible

A Bayesian technique for improving the sensitivity of the atmospheric neutrino L/E analysis

This paper outlines a method for improving the precision of atmospheric neutrino oscillation measurements. One experimental signature for these oscillations is an observed deficit in the rate of $\nu_{\mu}$ charged-current interactions with an oscillatory dependence on $L_{\nu}/E_{\nu}$, where $L_{\nu}$ is the neutrino propagation distance, and $E_{\nu}$ is the neutrino energy. For contained-vertex atmospheric neutrino interactions, the $L_{\nu}/E_{\nu}$ resolution varies significantly from event to event. The precision of the oscillation measurement can be improved by incorporating information on $L_{\nu}/E_{\nu}$ resolution into the oscillation analysis. In the analysis presented here, a Bayesian technique is used to estimate the $L_{\nu}/E_{\nu}$ resolution of observed atmospheric neutrinos on an event-by-event basis. By separating the events into bins of $L_{\nu}/E_{\nu}$ resolution in the oscillation analysis, a significant improvement in oscillation sensitivity can be achieved.Comment: 12 pages, 7 figures, submitted to Nucl. Instrum. Methods A, accompanies arXiv:1208.2915 [hep-ex

Eimeria species occurrence varies between geographic regions and poultry production systems and may influence parasite genetic diversity

Coccidiosis is one of the biggest challenges faced by the global poultry industry. Recent studies have highlighted the ubiquitous distribution of all Eimeria species which can cause this disease in chickens, but intriguingly revealed a regional divide in genetic diversity and population structure for at least one species, Eimeria tenella. The drivers associated with such distinct geographic variation are unclear, but may impact on the occurrence and extent of resistance to anticoccidial drugs and future subunit vaccines. India is one of the largest poultry producers in the world and includes a transition between E. tenella populations defined by high and low genetic diversity. The aim of this study was to identify risk factors associated with the prevalence of Eimeria species defined by high and low pathogenicity in northern and southern states of India, and seek to understand factors which vary between the regions as possible drivers for differential genetic variation. Faecal samples and data relating to farm characteristics and management were collected from 107 farms from northern India and 133 farms from southern India. Faecal samples were analysed using microscopy and PCR to identify Eimeria occurrence. Multiple correspondence analysis was applied to transform correlated putative risk factors into a smaller number of synthetic uncorrelated factors. Hierarchical cluster analysis was used to identify poultry farm typologies, revealing three distinct clusters in the studied regions. The association between clusters and presence of Eimeria species was assessed by logistic regression. The study found that large-scale broiler farms in the north were at greatest risk of harbouring any Eimeria species and a larger proportion of such farms were positive for E. necatrix, the most pathogenic species. Comparison revealed a more even distribution for E. tenella across production systems in south India, but with a lower overall occurrence. Such a polarised region- and system-specific distribution may contribute to the different levels of genetic diversity observed previously in India and may influence parasite population structure across much of Asia and Africa. The findings of the study can be used to prioritise target farms to launch and optimise appropriate anticoccidial strategies for long-term control