258 research outputs found
Osprey Nest Abundance, Distribution, and Productivity in Casco Bay
With support from the Casco Bay Estuary Partnership (CBEP), and in collaboration with the Maine Department of Inland Fisheries and Wildlife (MDIFW), Biodiversity Research Institute (BRI) initiated efforts to collect a 3-year (2011-2013) baseline on Osprey nest abundance, distribution, and productivity in Casco Bay. This survey effort represents the first comprehensive inventory ever to be conducted on Ospreys in Casco Bay, and it will enable evaluations of long-term population trends by comparing to existing datasets held by the MDIFW. Findings from the 2011 season are summarized in a full report submitted to CBEP (DeSorbo et al.2013). Here, we provide a brief summary of the results of the Osprey survey conducted in 2012 (year two). The purpose of this report is to provide a brief summary of preliminary findings from the 2012 season. An in-depth comparison to 2011 findings and a more extensive analysis of the factors contributing to overall patterns observed will be the subject of future reports
Osprey Nest Abundance, Distribution, and Productivity in Casco Bay
Ospreys are one of the most well-established ecological bioindicator species because their nest distribution and productivity reflect patterns and changes in the foodweb that supports them. Osprey tissues (eggs, blood, feathers) reflect contaminants in aquatic ecosystems and as a result, they are regularly sampled throughout their range to monitor geographic and temporal contaminant patterns
Experimental study of the correlation length of critical-current fluctuations in the presence of surface disorder: Probing vortex long-range interactions
We report on critical currents and voltage noise measurements in Niobium
strips in the superconducting state, in the presence of a bulk vortex lattice
() and in the surface superconducting state ().
For homogeneous surfaces, the correlation length of the current fluctuations
can be associated with the electromagnetic skin depth of vortex superficial
instabilities. The modification of the surface state by means of low energy
irradiation induces a strong modification of the critical current and of the
noise. The appearance of a corner frequency in the spectral domain can be
linked with the low wave-vectors of the artificial corrugation. Since this
latter occurs only for , we propose that the long-range
interactions allow the correlation length to extend up to values imposed by the
surface topography.Comment: accepted for publication in PR
Child-mediated health communication: A conceptual framework for increasing stroke literacy in hard to reach populations
Effectively engaging economically-disadvantaged ethnic minority communities for promoting health has proved to be challenging for a variety of reasons, including factors related to healthcare access, literacy, inadequate or ineffective cultural appropriateness of materials, and the relatively low priority for health due to competing demands related to economic hardship. We have developed a framework of Child-Mediated Health Communication (CMHC), which focuses on children as channels for carrying out health promotion interventions to parents and other caregivers. CMHC is an innovative, alternative strategy for engaging this underserved population, where traditional methods of health promotion have not been successful. We discuss the theoretical foundation, development, and effectiveness of a CMHC framework in our stroke preparedness communication intervention, Hip Hop Stroke
Anomalous Sliding Friction and Peak Effect near the Flux Lattice Melting Transition
Recent experiments have revealed a giant "peak effect" in ultrapure high
superconductors. Moreover, the new data show that the peak effect
coincides exactly with the melting transition of the underlying flux lattice.
In this work, we show using dynamical scaling arguments that the friction due
to the pinning centers acting on the flux lattice develops a singularity near a
continuous phase transition and can diverge for many systems. The magnitude of
the nonlinear sliding friction of the flux lattice scales with this atomistic
friction. Thus, the nonlinear conductance should diverge for a true continuous
transition in the flux lattice or peak at a weakly first order transition or
for systems of finite size.Comment: 4 pages, to appear in Phys. Rev.
Thermodynamics of Nonstoichiometric Nickel Tellurides. I. Heat Capacity and Thermodynamic Functions of the Ύ Phase from 5 to 350°K
Heat capacities of the nickel tellurides were measured at compositions NiTe1.1 and NiTe2.0 (near limits of homogeneity of the ÎŽ phase) and at one intermediate composition, NiTe1.5, from 5 to 350°K. Heat capacity values and entropy and enthalpy increments are tabulated. No evidence of orderâdisorder transitions, or thermal anomalies, or of contributions to the thermal properties from the anisotropy or phonon scattering by the holes in the structure on approaching the composition NiTe2 was observed. Although simple additivity of the heat capacities of the constituent elements failed to represent that of the solution compositions adequately, a KoppâNeumann treatment in terms of the limiting compositions of the ÎŽ phase gives good agreement with the experimental heat capacity and entropy of NiTe1.5 and hence is useful in interpolating to other intermediate compositions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70090/2/JCPSA6-28-3-497-1.pd
Experiments in vortex avalanches
Avalanche dynamics is found in many phenomena spanning from earthquakes to
the evolution of species. It can be also found in vortex matter when a type II
superconductor is externally driven, for example, by increasing the magnetic
field. Vortex avalanches associated with thermal instabilities can be an
undesirable effect for applications, but "dynamically driven" avalanches
emerging from the competition between intervortex interactions and quenched
disorder constitute an interesting scenario to test theoretical ideas related
with non-equilibrium dynamics. However, differently from the equilibrium phases
of vortex matter in type II superconductors, the study of the corresponding
dynamical phases - in which avalanches can play a role - is still in its
infancy. In this paper we critically review relevant experiments performed in
the last decade or so, emphasizing the ability of different experimental
techniques to establish the nature and statistical properties of the observed
avalanche behavior.Comment: To be published in Reviews of Modern Physics April 2004. 17 page
Effect of Crystallographic Texture on Magnetic Characteristics of Cobalt Nanowires
Cobalt nanowires with controlled diameters have been synthesized using electrochemical deposition in etched ion-track polycarbonate membranes. Structural characterization of these nanowires with diameter 70, 90, 120 nm and length 30 ÎŒm was performed by scanning electron microscopy, high-resolution transmission electron microscopy, and X-ray diffraction techniques. The as-prepared wires show uniform diameter along the whole length and X-ray diffraction analysis reveals that [002] texture of these wires become more pronounced as diameter is reduced. Magnetic characterization of the nanowires shows a clear difference of squareness and coercivity between parallel and perpendicular orientations of the wires with respect to the applied field direction. In case of parallel applied field, the coercivity has been found to be decreasing with increasing diameter of the wires while in perpendicular case; the coercivity observes lower values for larger diameter. The results are explained by taking into account the magnetocrystalline and shape anisotropies with respect to the applied field and domain transformation mechanism when single domain limit is surpassed
Infrared Emission from Interstellar Dust. I. Stochastic Heating of Small Grains
We present a method for calculating the infrared emission from a population
of dust grains heated by starlight, including very small grains for which
stochastic heating by starlight photons results in high temperature transients.
Because state-to-state transition rates are generally unavailable for complex
molecules, we consider model PAH, graphitic, and silicate grains with realistic
vibrational mode spectra and realistic radiative properties. The vibrational
density of states is used in a statistical-mechanical description of the
emission process. Unlike previous treatments, our approach fully incorporates
multiphoton heating effects, important for large grains or strong radiation
fields. We discuss how the "temperature" of the grain is related to its
vibrational energy. By comparing with an "exact" statistical calculation of the
emission process, we determine the conditions under which the "thermal" and the
"continuous cooling" approximations can be used to calculate the emission
spectrum.
We present results for the infrared emission spectra of PAH grains of various
sizes heated by starlight. We show how the relative strengths of the 6.2, 7.7,
and 11.3um features depend on grain size, starlight spectrum and intensity, and
grain charging conditions. We show results for grains in the "cold neutral
medium", "warm ionized medium", and representative conditions in
photodissociation regions. Our model results are compared to observed ratios of
emission features for reflection nebulae and photodissociation regions, the
Milky Way, normal spiral galaxies, and starburst galaxies.Comment: Submitted to ApJ. 42 pages, 18 figures, Late
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