High Efficiency Positron Accumulation for High-Precision Measurements

Positrons are accumulated within a Penning trap designed to make more precise measurements of the positron and electron magnetic moments. The retractable radioactive source used is weak enough to require no license for handling radioactive material and the radiation dosage one meter from the source gives an exposure several times smaller than the average radiation dose on the earth's surface. The 100 mK trap is mechanically aligned with the 4.2 K superconducting solenoid that produces a 6 tesla magnetic trapping field with a direct mechanical coupling.Comment: 7 pages, 9 figure

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

The Direction of Research and Management of Double-crested Cormorants Heading into the 2000s: Symposium Overview and Future Information Needs

An overview is provided of a symposium on the direction of research and management of Doublecrested Cormorants (Phalacrocorax auritus) heading into the 2000s. The current symposium built on previous efforts and described a number of focus areas of informational need, including cormorant impacts on natural resources, demographics of cormorants, assessment of control efforts, assessment of fish consumption and bioenergetics, and cormorant spatial ecology and influences on movements. The cormorant symposium highlighted a shift in research focus relative to earlier symposia, from evaluating potential impacts on commercial and natural resources to evaluating management actions in attaining desired goals. In addition, the symposium addressed the pressing need to obtain baseline information on cormorant population demographics. The shift reflects a response to increasing management efforts and intensity in North America and the need to understand the effects and effectiveness of increased cormorant control at several spatial scales. The symposium furthered communication and the sharing of information on cormorant issues in North America. However, uncertainty regarding impacts to cormorants associated with policy changes and management actions and outcomes presents significant future challenges

The Probability of Winning at Solitaire: A Preliminary Description of a State-Transition Approach

This paper is the very beginning of a proposal of an approach that may offer a method for solving a currently unsolved problem - calculating the probability of winning at Solitaire. We describe the game as a series of state transitions, from an initial state to a winning state. The state variables and allowable transitions are described, and a list of “next steps” is given. It is hoped that this approach may prove fruitful

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

Migratory Flyways May Affect Population Structure in Double‐Crested Cormorants

Double‐crested cormorants (Phalacrocorax auritus) recovered from a demographic bottleneck so well that they are now considered a nuisance species at breeding and wintering grounds across the United States and Canada. Management of this species could be improved by refining genetic population boundaries and assigning individuals to their natal population. Further, recent radio‐telemetry data suggest the existence of Interior and Atlantic migratory flyways, which could reduce gene flow and result in substantial genetic isolation. In this study, we used 1,784 individuals collected across the eastern United States, a large panel of microsatellite markers developed for this species, and individuals banded as chicks and recaptured as adults to explore the effects of migratory flyways on population structure, quantify the genetic effects of demographic bottlenecks, and determine whether individuals could be assigned to their natal population based on genotype. We found evidence for genetic population division only along migratory flyways, no evidence of genetic bottlenecks, and mixed effectiveness of assignment tests. Our population structure findings suggest that gene flow is high across large scales; for example, individuals from New York, Minnesota, and Alabama are all in panmixia. We also found that traditional subspecies ranges may not be valid because \u3e1 subspecies was present in single genetic populations. The lack of evidence for genetic bottlenecks also likely underscores the vagility of this species, suggesting that even during demographic bottlenecks, populations were not isolated from allelic exchange. Finally, the failure of assignment tests to consistently perform is likely due in part to imperfect a priori sampling of Atlantic and Interior chicks and the high vagility of adults. We conclude that the demographic bottleneck is not likely to have reduced genetic diversity, and that assignment tests remain unreliable for this species. We recommend double-crested cormorants be managed by flyway. Further development of genomic resources in this species could improve population subdivision resolution, improve assignment tests, and reveal further information on demographic histories

Performance of selected agricultural spray nozzles using particle image velocimetry

The aim of the present study was to investigate the influence of nozzle configurations on spray drift and explain the influences using several atomization characteristics (length of spray sheet, spray angle, velocity distribution of flow field, fluctuation of velocity, and droplet size). Nozzles manufactured by one company (Lechler GmbH, Germany) were tested by spraying local tap water in a wind tunnel at an operating pressure of 0.3 MPa and under room temperature. The nozzles tested were compact air-induction flat fan nozzles (IDK120-02, IDK120-03), standard flat fan nozzles (ST110-02, ST110-03), and hollow-cone swirl nozzles (TR80-02, TR80-03). The atomization process was recorded using a Particle Image Velocimetry (PIV) system, droplet size was measured by a Sympatec Helos laser-diffraction particle-size analyzer, and spray drift was evaluated in a wind tunnel with deposition measured using a calibrated fluorometer (Turner-Sequoia model 450). Results showed that spray drift was significantly different among nozzle types (