1,501 research outputs found

    Notes on rare, vagrant and exotic avifauna at Macquarie Island, 1901-2000

    Get PDF
    The occurrence and status of rare, vagrant and exotic bird taxa recorded at Macquarie Island between 1901 and 2000 are reviewed. The number of species recorded at the island, excluding those that have bred regularly on the main island between 1901 and 2000, is increased to 56 non-breeding species, seven species that have been confirmed breeding since 1980 and four introduced/exotic species breeding on the island

    Universal Behavior in Large-scale Aggregation of Independent Noisy Observations

    Full text link
    Aggregation of noisy observations involves a difficult tradeoff between observation quality, which can be increased by increasing the number of observations, and aggregation quality which decreases if the number of observations is too large. We clarify this behavior for a protypical system in which arbitrarily large numbers of observations exceeding the system capacity can be aggregated using lossy data compression. We show the existence of a scaling relation between the collective error and the system capacity, and show that large scale lossy aggregation can outperform lossless aggregation above a critical level of observation noise. Further, we show that universal results for scaling and critical value of noise which are independent of system capacity can be obtained by considering asymptotic behavior when the system capacity increases toward infinity.Comment: 10 pages, 3 figure

    Black holes in which the electrostatic or scalar equation is solvable in closed form

    Full text link
    We show that the method used in the Schwarzschild black hole for finding the elementary solution of the electrostatic equation in closed form cannot extend in higher dimensions. By contrast, we prove the existence of static, spherically symmetric geometries with a non-degenerated horizon in which the static scalar equation can be solved in closed form. We give the explicit results in 6 dimensions. We determine moreover the expressions of the electrostatic potential and of the static scalar field for a point source in the extremal Reissner-Nordstrom black holes in higher dimensions.Comment: 20 pages, no figur

    Predators on marine fish farms in Tasmania

    Get PDF
    Marine aquaculture of the salmonids atlantic salmon (Salrno salar) and rainbow trout (Salmo gairdneri) is a rapidly growing industry in Tasmania. There is considerable damage to the fish on these farms by avian and mammalian predators. The mode by which these predators attack the fish on the farms allows for practical methods to reduce the loss of fish. Physically excluding predators from the fish is ultimately the only way to prevent this loss entirely. A total of six predators that interact with the farms are described and the necessity for the protection methods to be incorporated into the design of the farms prior to farm development is emphasised

    Initial state maximizing the nonexponentially decaying survival probability for unstable multilevel systems

    Full text link
    The long-time behavior of the survival probability for unstable multilevel systems that follows the power-decay law is studied based on the N-level Friedrichs model, and is shown to depend on the initial population in unstable states. A special initial state maximizing the asymptote of the survival probability at long times is found and examined by considering the spontaneous emission process for the hydrogen atom interacting with the electromagnetic field.Comment: 5 pages, 1 table. Accepted for publication in Phys. Rev.

    Understanding of BRCA VUS genetic results by breast cancer specialists.

    Get PDF
    BACKGROUND: Mainstreaming genetic medicine, increased media coverage and clinical trials for BRCA mutation carriers are leading oncologists into more patient discussions about BRCA genetic testing. BRCA variants of uncertain significance (VUS) occur in 10-20% of tests. VUS detection introduces additional uncertainty for patient and potentially clinician. We aimed to explore the ability of breast cancer specialists (BCS) in the UK to correctly respond to a VUS report. METHODS: A survey sent to 800 UK BCS collected demographics data, VUS general knowledge and interpretation and communication based on two genetics reports. A separate survey of UK clinical geneticists collected demographics data, laboratory reporting practice and methods used to clarify VUS pathogenicity including classification systems. RESULTS: Of the 155 BCS (22.5%) who completed the survey, 12% reported no genetics training. Ninety five percent referred patients for BRCA genetic tests, 71% felt unsure about the clinical implications of the test reports presented here. A VUS report from a patient with a positive family history was interpreted and theoretically communicated correctly by 94% but when presented with a different VUS report with no management guidance and negative family history, 39% did not know how to communicate this result to the patient. Geneticists reported multiple VUS classification systems; the most commonly used was word-based in 32%. CONCLUSIONS: A consistent and standardised format to report particularly VUS results across all diagnostic laboratories plus additional training of UK BCS will be necessary for effective mainstreaming of BRCA testing to the oncology clinic

    Initial wave packets and the various power-law decreases of scattered wave packets at long times

    Full text link
    The long time behavior of scattered wave packets ψ(x,t)\psi (x,t) from a finite-range potential is investigated, by assuming ψ(x,t)\psi (x,t) to be initially located outside the potential. It is then shown that ψ(x,t)\psi (x,t) can asymptotically decrease in the various power laws at long time, according to its initial characteristics at small momentum. As an application, we consider the square-barrier potential system and demonstrate that ψ(x,t)\psi (x,t) exhibits the asymptotic behavior t3/2t^{-3/2}, while another behavior like t5/2t^{-5/2} can also appear for another ψ(x,t)\psi (x,t).Comment: 5 pages, 1 figur

    Electrostatics in a Schwarzschild black hole pierced by a cosmic string

    Get PDF
    We explicitly determine the expression of the electrostatic potential generated by a point charge at rest in the Schwarzschild black hole pierced by a cosmic string. We can then calculate the electrostatic self-energy. From this, we find again the upper entropy bound for a charged object by employing thermodynamics of the black hole.Comment: Latex, 8 pages, 1 figure in late
    corecore