Construction of an Inexpensive Lighted Sorting Chamber

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141750/1/naaq0063.pd

Using pentosidine and hydroxyproline to predict age and sex in an avian species

All living organisms are subject to senescence accompanied by progressive and irreversible physiological changes. The error damage and cross-linking theories suggest that cells and tissues are damaged by an accumulation of cross-linked proteins, slowing down bodily processes and resulting in aging. A major category of these cross-linked proteins are compounds called advanced glycation end products (AGEs). We investigated the relationship between accumulation of the AGE, pentosidine (Ps), and hydroxyproline (HYP) a post-translationally modified amino acid, with age, sex, and breeding status (breeder/ nonbreeder) from skin samples of known age (i.e., banded as fledglings), free-ranging Double-crested Cormorants (Phalacrocorax auritus, Lesson 1831). We developed multivariate models and evaluated the predictive capability of our models for determining age and breeding versus nonbreeding birds. We found significant relationships with Ps and HYP concentration and age, and Ps concentration and sex. Based on our two-class model using Ps and HYP as explanatory variables, we were able to accurately determine whether a cormorant was a breeder or nonbreeder in 83.5% of modeled classifications. Our data indicate that Ps and HYP concentrations can be used to determine breeding status of cormorants and potentially age of cormorants although sex-specific models may be necessary. Although the accumulation of Ps explained the greatest amount of variance in breeding status and age, importantly, Ps covaried with HYP and combined improved prediction of these demographics in cormorants. Our data support the error damage and cross-linking theories of aging. Both Ps and HYP increase predictably in cormorants and are predictive of age and breeding status. Given the ubiquity of these biomarkers across taxa, their use in estimating demographic characteristics of animals could provide a powerful tool in animal ecology, conservation, and management

High-order Discretization of a Gyrokinetic Vlasov Model in Edge Plasma Geometry

We present a high-order spatial discretization of a continuum gyrokinetic Vlasov model in axisymmetric tokamak edge plasma geometries. Such models describe the phase space advection of plasma species distribution functions in the absence of collisions. The gyrokinetic model is posed in a four-dimensional phase space, upon which a grid is imposed when discretized. To mitigate the computational cost associated with high-dimensional grids, we employ a high-order discretization to reduce the grid size needed to achieve a given level of accuracy relative to lower-order methods. Strong anisotropy induced by the magnetic field motivates the use of mapped coordinate grids aligned with magnetic flux surfaces. The natural partitioning of the edge geometry by the separatrix between the closed and open field line regions leads to the consideration of multiple mapped blocks, in what is known as a mapped multiblock (MMB) approach. We describe the specialization of a more general formalism that we have developed for the construction of high-order, finite-volume discretizations on MMB grids, yielding the accurate evaluation of the gyrokinetic Vlasov operator, the metric factors resulting from the MMB coordinate mappings, and the interaction of blocks at adjacent boundaries. Our conservative formulation of the gyrokinetic Vlasov model incorporates the fact that the phase space velocity has zero divergence, which must be preserved discretely to avoid truncation error accumulation. We describe an approach for the discrete evaluation of the gyrokinetic phase space velocity that preserves the divergence-free property to machine precision

Double-crested cormorant colony effects on soil chemistry, vegetation structure and avian diversity

Effects of Double-crested Cormorants (Phalacrocorax auritus) on vegetation, soil chemistry and tree health have been documented from their breeding colonies in the northern breeding grounds of Canada and the United States (U.S.) but not for areas within the southeastern United States where breeding activity is relatively novel. We compared vegetation and tree metrics such as structure diversity, and soil chemistry among colony islands, uninhabited islands, and abandoned colony islands within Guntersville Reservoir, a temperate forest ecosystem. Avian diversity and community structure were also quantified on these islands. Concentrations of potassium (K), phosphorus (P) and nitrate (NO3 −) in soil were negatively related to cormorant use, while tree diversity was lower on historic (tree mean=4.35 ± 2.46 species) and colony (tree mean=3.91 ± 3.12 species) islands relative to reference islands (tree mean=9.11 ± 3.88 species). Canopy cover was less (min:\u3c20%), and midstories denser on colony and historic islands relative to reference islands. Avian diversity was significantly lower for colony islands (mean=6 ± 3 species) than both reference (11 ± 7 species) and historic (10 ± 7 species) islands. These effects of cormorant nesting can be seen even after 10 years of colony abandonment supporting that cormorants can have long-term effects on insular habitats in temperate forest ecosystems

Space Use and Movements of Southeastern Breeding Double-Crested Cormorants (\u3ci\u3eNannopterum auritum\u3c/i\u3e) in the United States

Abstract: Seasonal movements of Double-crested Cormorants (Nannopterum auritum) have been studied at breeding and wintering sites in the southeastern United States, but little information exists on the movements of these birds within and from their southern breeding sites in lacustrine systems. Since 2001, cormorants have established nesting colonies on islands in Guntersville Reservoir in Alabama, USA. Following the movements of tagged cormorants using satellite telemetry, we found that the mean home range during the 2017 breeding season (May–August) was 41.76 km2, with a core use area of 6.36 km2. The mean home range used by these birds was largest during the period coinciding with incubation: 9–30 May: (98.86 ± 80.64 km2) compared with the chick-rearing 31 May–4 July: 18.30 ± 22.56 km2), and the post-fledge periods (5 July–15 August: 42.04 ± 30.95 km2). There was no significant difference in the metrics of movement and space use between male and female cormorants assessed in this study. Differences in space used by cormorants breeding in Alabama relative to their northern breeding grounds may be explained by landscape characteristics and availability of prey

Evaluation of phenotypic and genotypic approaches as predictors of Salmonella strains of clinical and non-clinical origin

This study investigated the possible phenotypic and genotypic similarities and differences between Salmonella isolates obtained from swine with clinical salmonellosis to isolates obtained from swine showing no clinical disease. Phenotypic analysis was done by antimicrobial resistance profiling and amplified fragment length polymorphism (AFLP) fingerprinting was employed for genotypic analysis

Diamonds are Forever

We defend the thesis that every necessarily true proposition is always true. Since not every proposition that is always true is necessarily true, our thesis is at odds with theories of modality and time, such as those of Kit Fine and David Kaplan, which posit a fundamental symmetry between modal and tense operators. According to such theories, just as it is a contingent matter what is true at a given time, it is likewise a temporary matter what is true at a given possible world; so a proposition that is now true at all worlds, and thus necessarily true, may yet at some past or future time be false in the actual world, and thus not always true. We reconstruct and criticize several lines of argument in favor of this picture, and then argue against the picture on the grounds that it is inconsistent with certain sorts of contingency in the structure of time

The role of truck wash practices in dissemination of Salmonella and Campylobacter in commercial swine production

This study investigated the sources of two foodborne pathogens, Salmonella and Campylobacter in a commercial swine production system. Pathogens were characterized using conventional culture and isolation techniques and antibiograms