758 research outputs found

    Relationships between Meteorological and other Variables and Bobwhite Spring Call Counts

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    Accurate assessment of quail population trends is critical to the success of future conservation efforts. Financial considerations and time constraints often limit population trend estimates to indices, the most common of which are spring call counts and autumn covey counts. While all indices have limitations and caveats, spring call count data specifically possess variability that makes them ill-suited for detecting fine-scale trends. However, because spring call counts record calling males and are relatively easy to conduct, they are assumed to represent an index of breeding potential and produce the most data per unit cost. Here, we examine their variability, comparing the number of male northern bobwhites (Colinus virginianus; hereafter, bobwhite) calling and weather measurements recorded during \u3e4,000 spring call counts conducted May–July 2014–2017. The number of male bobwhites recorded per call count decreased \u3e2 hours after sunrise, as ambient temperatures increased, but increased with relative humidity. An increase in ambient noise was associated with recording fewer male bobwhites. There was no correlation with either wind speed/hour for 3 of 4 years, or with the Palmer Drought Severity Index. Comparing these results with other spring call counts in the literature highlights inconsistency in spring call count timing, and discrepancies between call count protocols and weather conditions that affect detection probability. We suggest incorporating these results into future call counts to more accurately assess bobwhite population trends

    The Resonance Peak in Sr2_2RuO4_4: Signature of Spin Triplet Pairing

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    We study the dynamical spin susceptibility, χ(q,ω)\chi({\bf q}, \omega), in the normal and superconducting state of Sr2_2RuO4_4. In the normal state, we find a peak in the vicinity of Qi(0.72π,0.72π){\bf Q}_i\simeq (0.72\pi,0.72\pi) in agreement with recent inelastic neutron scattering (INS) experiments. We predict that for spin triplet pairing in the superconducting state a {\it resonance peak} appears in the out-of-plane component of χ\chi, but is absent in the in-plane component. In contrast, no resonance peak is expected for spin singlet pairing.Comment: 4 pages, 4 figures, final versio

    Analysis of Predator Avoidance Behavior in California Valley Quail

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    Quail populations have been in decline across the United States, primarily due to habitat loss and climate. For remedy, landowners and game managers have attempted to restore populations by releasing captive-reared quail. These releases were largely unsuccessful, presumably due to high predation losses. Recently, there has been an increased interest in quail translocations, which tend to have lower mortality rates than captive-reared bird releases. Translocations are expensive and unpredictable, and require many person-hours; releasing captive-reared quail would be more efficient if the practice were successful. We compared predator avoidance behavior between captive-reared and wild-translocated California quail (Callipepla californica) in an aviary using simulated predator attacks (raptorial and mammalian). We recorded predator detection time, antipredator response time, and antipredator response type. Antipredator response type (run, flush, or freeze) frequencies were different, where captive-reared quail ran more frequently than wild-translocated quail when encountering a simulated predator. Predator detection time between captive-reared and wild-translocated quail was not different. However, antipredator response time was quicker for captive-reared quail than wild-translocated quail when subjected to simulated raptorial and mammalian attacks. The differences in antipredator response time and response type may be due to the lack of predator interaction experience of captive-reared birds and offer insight into observed differences in postrelease mortality between captive-reared and wild-trapped quail

    Dirty black holes: Entropy versus area

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    Considerable interest has recently been expressed in the entropy versus area relationship for ``dirty'' black holes --- black holes in interaction with various classical matter fields, distorted by higher derivative gravity, or infested with various forms of quantum hair. In many cases it is found that the entropy is simply related to the area of the event horizon: S = k A_H/(4\ell_P^2). For example, the ``entropy = (1/4) area'' law *holds* for: Schwarzschild, Reissner--Nordstrom, Kerr--Newman, and dilatonic black holes. On the other hand, the ``entropy = (1/4) area'' law *fails* for: various types of (Riemann)^n gravity, Lovelock gravity, and various versions of quantum hair. The pattern underlying these results is less than clear. This paper systematizes these results by deriving a general formula for the entropy: S = {k A_H/(4\ell_P^2)} + {1/T_H} \int_\Sigma [rho - {L}_E ] K^\mu d\Sigma_\mu + \int_\Sigma s V^\mu d\Sigma_\mu. (K^\mu is the timelike Killing vector, V^\mu the four velocity of a co--rotating observer.) If no hair is present the validity of the ``entropy = (1/4) area'' law reduces to the question of whether or not the Lorentzian energy density for the system under consideration is formally equal to the Euclideanized Lagrangian. ****** To appear in Physical Review D 15 July 1993 ****** [Stylistic changes, minor typos fixed, references updated, discussion of the Born-Infeld system excised]Comment: plain LaTeX, 17 pages, minor revision

    Translocating Wild California Valley Quail to Texas: An Evaluation of Survival, Dispersal, Tracking Efficacy, and Roost Preference

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    Quail translocations are becoming increasingly popular in regions of suitable habitat where local quail populations have declined. In northeastern Texas, USA, northern bobwhite (Colinus virginianus) populations have drastically declined for over a century and have reached undetectable levels in many areas. As a result, the number of quail hunters and quail conservation funding have also declined. California valley quail (Callipepla californica; hereafter, valley quail) have increased across their range and have been translocated to many states and countries. Thus, the goal of this study was to determine whether translocating wild valley quail to Texas was feasible, and evaluate their survival, dispersal, roost location preference, and potential predator impacts. We translocated 748 wild valley quail from Idaho, USA to northeastern Texas in 2019 and 2020. We collected quail location data from very high frequency (VHF) and digital transmitters. Motion-triggered cameras, scent stations, simulated nests, and raptor transects were used to record predator presence and potential predator impacts. Survival of birds with tracking devices was 63% (VHF) in 2019, and 38.8% (VHF) and 92.5% (digital tag) in 2020. Survival was greater for quail with digital transmitters. Median dispersal distance was 633.5 m in 2019 and 246.6 m in 2020 for valley quail with VHF transmitters, and 310.4 m for quail with digital transmitters. Minimum convex polygon area medians were 4.3 ha in 2019 and 3.1 ha in 2020 for quail with VHF transmitters, and 16.1 ha in 2020 for quail with digital transmitters. Roost sites were primarily in young stands of oak trees. Median simulated nest survival was 2 days (minimum [min] = 1, interquartile range [IQR] = 2–5.4, maximum [max] = 23) in 2019, and 7.5 days (min = 2, IQR = 4.5–15.2, max = 23) in 2020. The most frequent mammalian predators observed were raccoons (Procyon lotor), feral hogs (Sus scrofa), and white-tailed deer (Odocoileus virginianus). Red-tailed hawks (Buteo jamaicensis) were the most frequent aerial predator. We completed the first documented translocation of wild California valley quail to Texas, demonstrating it is feasible. Future translocation may benefit from translocating more birds over a longer period of time, with more consistent methodology. The establishment of a sustainable population may require ≥7 years of translocation at a rate of 500 birds per year with \u3e2,000 ha of suitable habitat

    Climate Impacts on North American Quail

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    North America’s quail population trends are often linked to regional climate. Extreme climate events such as severe drought, hard freezes, or excessive winter precipitation can reduce quail populations by as much as 84%. Above-average spring and summer temperatures coincident with drought can reduce the laying season for quail by ≤60 days. Exposure of quail eggs to high temperatures during preincubation can initiate and alter embryonic development. Here, we review the impacts of extreme climate events and a changing climate on the survival, reproduction, and population trends of 6 North American quail species: California quail (Callipepla californica), Gambel’s quail (Callipepla gambelii), Montezuma quail (Cyrtonix montezumae), mountain quail (Oreortyx pictus), northern bobwhite (Colinus virginianus), and scaled quail (Callipepla squamata). Climate change scenarios are especially troubling when considered in conjunction with the heat stress hypothesis, which suggests that reproduction is reduced during heat and drought events by elevated corticosterone levels due to heat stress. Global climate change is predicted to increase the west-to-east precipitation gradient across North America. While eastern North America will see more frequent heavy precipitation events, western North America will experience more frequent and severe spring heat waves, droughts, and wildfires. These will further imperil western quail populations in the near term by decreasing the frequency of successful reproductive events. Over the long term, we expect both an elevational increase and southwest-to-northeast shift in species ranges, and concordant extirpation of local populations. Of North American quail species, California quail may see its range contract the most, approximately 50% under a 3° C global temperature increase scenario. Conversely, milder winters may increase the area over which climate is favorable to bobwhites by approximately 25%. However, these gains will largely be contiguous with regions where bobwhite populations are rapidly declining, or have been extirpated, due to intensive agriculture and other land use changes. Extirpation of local populations may not be reversible, as there are few examples of successfully reestablished populations. There is a critical need for a national recovery plan that incorporates the impacts of future climate change on quail populations. We recommend that incorporating quail and other grassland birds into agricultural enterprises become standard practice. Long-term solutions will require increasing habitat quantity and connectivity. We also recommend research to further test and expand upon the heat stress hypothesis, and we recommend land management practices to mitigate the negative consequences of climate change

    Fluid Models of Many-server Queues with Abandonment

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    We study many-server queues with abandonment in which customers have general service and patience time distributions. The dynamics of the system are modeled using measure- valued processes, to keep track of the residual service and patience times of each customer. Deterministic fluid models are established to provide first-order approximation for this model. The fluid model solution, which is proved to uniquely exists, serves as the fluid limit of the many-server queue, as the number of servers becomes large. Based on the fluid model solution, first-order approximations for various performance quantities are proposed

    Stress and Predation Impacts on North American Quail Translocations

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    Translocations have been used in attempts to bolster or restore native quail populations for \u3e150 years, often with little success. However, with some northeastern United States quail populations undetectable or extirpated, and others across the United States on the extreme decline, translocation as a tool for quail population restoration is becoming increasingly popular. Two factors contributing to translocation failure are physiological stress and predation. Chronic stress associated with translocations can result in weight loss, reduced immune system function, suppressed reproduction, and an altered fight-or-flight response. These stress-induced responses increase vulnerability to predation, the primary cause of quail mortality. Here, we review the relationship between quail translocations, stress, and predation, and recommend future research and best practices to mitigate the impacts of stress and predation on translocated quail. To improve future translocation outcomes, more research is needed on stress mitigation throughout the translocation process (capture, handling, transport, and release). While capture and handling are unavoidably stressful, there is greater potential to reduce stress levels during holding and transport. Recent validation of fecal corticosterone metabolites as a non-invasive method to quantify stress in quail offers a useful tool for testing stress reduction protocols. Preliminary experimental results regarding nutritional supplements and stress levels are inconclusive, but enrichment during temporary holding and access to travel rations may help improve survival in long-distance (\u3e800 km) translocations. We also recommend predator control at release sites, particularly for raccoons (Procyon lotor) and other mesomammals

    Quantum Cosmology for a Quadratic Theory of Gravity

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    For pure fourth order (LR2{\cal{L}} \propto R^2) quantum cosmology the Wheeler-DeWitt equation is solved exactly for the closed homogeneous and isotropic model. It is shown that by imposing as boundary condition that Ψ=0\Psi = 0 at the origin of the universe the wave functions behave as suggested by Vilenkin.Comment: 13 pages, latex,no figure

    Charged Black Holes In Quadratic Theories

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    We point out that in general the Reissner-Nordstr\"om (RN) charged black holes of general relativity are not solutions of the four dimensional quadratic gravitational theories. They are, e.g., exact solutions of the R+R2R+R^2 quadratic theory but not of a theory where a RabRabR_{ab}R^{ab} term is present in the gravitational Lagrangian. In the case where such a non linear curvature term is present with sufficiently small coupling, we obtain an approximate solution for a charged black hole of charge QQ and mass MM. For QMQ\ll M the validity of this solution extends down to the horizon. This allows us to explore the thermodynamic properties of the quadratic charged black hole and we find that, to our approximation, its thermodynamics is identical to that of a RN black hole. However our black hole's entropy is not equal to the one fourth of the horizon area. Finally we extend our analysis to the rotating charged black hole and qualitatively similar results are obtained.Comment: 11 pages, LaTeX/RevTeX3.
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