18,618 research outputs found
Winter Home Range and Habitat Use of the Virginia Northern Flying Squirrel (Glaucomys sabrinus fuscus)
We radio-tracked two male and one female Virginia northern flying squirrels (Glaucomys sabrinus fuscus) in the Allegheny Mountains of West Virginia at Snowshoe Mountain Resort, in winter 2003 and Canaan Valley National Wildlife Refuge in winter 2004, respectively, to document winter home range and habitat use in or near ski areas. Male home range size in the winter was larger than that reported for males during summer and fall, whereas the female home range we observed was smaller than those reported for summer and fall. However, winter habitat use was similar to summer and fall habitat use reported in other studies. Virginia northern flying squirrels foraged and denned in both red spruce (Picea rubens)-dominated forests and northern hardwood forests; however, selection of red spruce-dominated forests and open areas was greater than expected based on availability. Use of northern hardwood forest occurred less than expected based on availability. Male squirrels denned near, and routinely crossed, downhill ski slopes and unimproved roads during foraging bouts, whereas the female approached, but did not cross forest edges onto roads or trails
Microgastrinae (Hymenoptera: Braconidae) parasitizing Epirrita autumnata (Lepidoptera: Geometridae) larvae in Fennoscandia with description of Cotesia autumnatae Shaw, sp. n.
The microgastrine subset of hymenopteran parasitoids of the geometrid Epirrita
autumnata is investigated in Fennoscandia. Ecology, including population dynamics,
of the moth has been intensively studied in northern and mountainous
Finland, Norway and Sweden. Recently supported hypotheses about the causes
of its cyclic population dynamics stress the role of parasitoids, while the
parasitoid complex with some 15 species is insufficiently known. The complex
includes four solitarymicrogastrine species, Protapanteles anchisiades (Nixon),
P. immunis (Wesmael), Cotesia salebrosa (Marshall) and C. autumnatae Shaw,
sp. n. Here, we provide detailed figures for the latter, which is morphologically
close to C. jucunda (Marshall), and describe the species as new to science. We
also providemore general habitus figures of the other three species, as well as an
identification key for the four species, aiming to aid recognition of these species
by ecologists dealingwithmicrogastrine parasitoids of E. autumnata and their alternative
geometrid hosts
A smart environment for biometric capture
The development of large scale biometric systems require experiments to be performed on large amounts of data. Existing capture systems are designed for fixed experiments and are not easily scalable. In this scenario even the addition of extra data is difficult. We developed a prototype biometric tunnel for the capture of non-contact biometrics. It is self contained and autonomous. Such a configuration is ideal for building access or deployment in secure environments. The tunnel captures cropped images of the subject's face and performs a 3D reconstruction of the person's motion which is used to extract gait information. Interaction between the various parts of the system is performed via the use of an agent framework. The design of this system is a trade-off between parallel and serial processing due to various hardware bottlenecks. When tested on a small population the extracted features have been shown to be potent for recognition. We currently achieve a moderate throughput of approximate 15 subjects an hour and hope to improve this in the future as the prototype becomes more complete
Viscous damping of r-modes: Small amplitude instability
We study the viscous damping of r-modes of compact stars and analyze in
detail the regions where small amplitude modes are unstable to the emission of
gravitational radiation. We present general expressions for the viscous damping
times for arbitrary forms of interacting dense matter and derive general
semi-analytic results for the boundary of the instability region. These results
show that many aspects, like in particular the physically important minima of
the instability boundary, are surprisingly insensitive to detailed microscopic
properties of the considered form of matter. Our general expressions are
applied to the cases of hadronic stars, strange stars, and hybrid stars, and we
focus on equations of state that are compatible with the recent measurement of
a heavy compact star. We find that hybrid stars with a sufficiently small core
can "masquerade" as neutron stars and feature an instability region that is
indistinguishable from that of a neutron star, whereas neutron stars with a
core density high enough to allow direct Urca reactions feature a notch on the
right side of the instability region.Comment: 22 pages, 16 figures, published versio
Dynamical Mass Estimates for the Halo of M31 from Keck Spectroscopy
The last few months have seen the measurements of the radial velocities of
all of the dwarf spheroidal companions to the Andromeda galaxy (M31) using the
spectrographs (HIRES and LRIS) on the Keck Telescope. This paper summarises the
data on the radial velocities and distances for all the companion galaxies and
presents new dynamical modelling to estimate the mass of extended halo of M31.
The best fit values for the total mass of M31 are between 7 and 10 x 10^{11}
solar masses, depending on the details of the modelling. The mass estimate is
accompanied by considerable uncertainty caused by the smallness of the dataset;
for example, the upper bound on the total mass is roughly 24 x 10^{11} solar
masses, while the lower bound is about 3 x 10^{11} solar masses. These values
are less than the most recent estimates of the most likely mass of the Milky
Way halo. Bearing in mind all the uncertainties, a fair conclusion is that the
M31 halo is roughly as massive as that of the Milky Way halo. There is no
dynamical evidence for the widely held belief that M31 is more massive -- it
may even be less massive.Comment: In press, The Astrophysical Journal (Letters
Atomic electron energies including relativistic effects and quantum electrodynamic corrections
Atomic electron energies have been calculated relativistically. Hartree-Fock-Slater wave functions served as zeroth-order eigenfunctions to compute the expectation of the total Hamiltonian. A first order correction to the local approximation was thus included. Quantum-electrodynamic corrections were made. For all orbitals in all atoms with 2 less than or equal to Z less than or equal to 106, the following quantities are listed: total energies, electron kinetic energies, electron-nucleus potential energies, electron-electron potential energies consisting of electrostatic and Breit interaction (magnetic and retardation) terms, and vacuum polarization energies. These results will serve for detailed comparison of calculations based on other approaches. The magnitude of quantum electrodynamic corrections is exhibited quantitatively for each state
The pervasiveness and implications of statistical misconceptions among academics with a special interest in business research methods
Statistics play a very important role in business research, particularly in studies that choose to use quantitative or mixed methods. Alongside statistical analysis, aspects related to research design (such as sampling, reliability and validity issues) require a good grounding in statistical concepts reinforced by careful practice to avoid potential mistakes arising from statistical misconceptions. Although quite a considerable number of published studies have focused on students' faulty thinking regarding statistical concepts, little research explores the extent to which these are also held by academics who are their instructors. This empirical study addresses this by answering the following questions: First, are statistical misconceptions pervasive among academics with a special interest in business research methods? If so, second, is there an association between the pervasiveness of statistical misconceptions and the preferred research tradition (qualitative, quantitative, mixed methods)?. Data were collected via a web questionnaire from a purposive sample of academics with an expressed interest in business research methods. The questionnaire comprised 30 categorical statements (agree, disagree, don't know) focusing on statistical misconceptions (and conceptions) relating to descriptive statistics, design strategies, inferential statistics and regression, and five demographic questions. We targeted a critical case purposive sample of 679 potential respondents. Although 166 consented to take part, only 80 completed the questionnaire and their responses form the basis of the statistical analysis, a response rate of 11.8 %. The study provides empirical evidence of both an absence of knowledge and a high pervasiveness of faulty notions that have infected the thinking of academics relating to both research design and the use of statistics. This is particularly so for academics who prefer quantitative methods, those preferring qualitative methods being more likely to admit that they do not know. The study argues that such lack of knowledge and misconceptions reduce the true utility of statistics in research. Recommendations are offered regarding the teaching of statistics within business research methods.peer-reviewe
Learning Incoherent Subspaces: Classification via Incoherent Dictionary Learning
In this article we present the supervised iterative projections and rotations (s-ipr) algorithm, a method for learning discriminative incoherent subspaces from data. We derive s-ipr as a supervised extension of our previously proposed iterative projections and rotations (ipr) algorithm for incoherent dictionary learning, and we employ it to learn incoherent sub-spaces that model signals belonging to different classes. We test our method as a feature transform for supervised classification, first by visualising transformed features from a synthetic dataset and from the ‘iris’ dataset, then by using the resulting features in a classification experiment
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