8,476 research outputs found
Nongame Birds, Small Mammals, Reptiles, Fishes: Sand Lake National Wildlife Refuge, 1995-1996
The goal of this study was to conduct a nongame vertebrate survey at SLNWR by primary habitat types, with emphasis placed on nongame breeding birds and small mammals . Specific objectives were to determine: 1) avian and mammalian species composition by primary habitat types with special emphasis on nongame/neotropical avian species and nongame small mammals, 2) the presence of other vertebrate species (amphibians, reptiles , and fishes) by primary habitat type, 3) present vertebrate biota occurrence, as compared to pre-1940 occurence as found in the literature and other records or sources, 4) significant changes in habitat and/ or vegetation on SLNWR, based on current and historical literature and refuge files, and 5) to make recommendations for preserving/ enhancing populations of nongame vertebrate species on SLNWR
Analytical Rebridging Monte Carlo: Application to cis/trans Isomerization in Proline-Containing, Cyclic Peptides
We present a new method, the analytical rebridging scheme, for Monte Carlo
simulation of proline-containing, cyclic peptides. The cis/trans isomerization
is accommodated by allowing for two states of the amide bond. We apply our
method to five peptides that have been previously characterized by NMR methods.
Our simulations achieve effective equilibration and agree well with
experimental data in all cases. We discuss the importance of effective
equilibration and the role of bond flexibility and solvent effects on the
predicted equilibrium properties.Comment: 29 pages, 8 PostScript figures, LaTeX source. to appear in J. Chem.
Phys., 199
Evaluation of enzyme immunoassays in the diagnosis of camel (Camelus dromedarius) trypanosomiasis:a preliminary investigation
Three enzyme immunoassays were used for the serodiagnosis of Trypanosoma evansi in camels in the Sudan in order to evaluate their ability to discriminate between infected and non-infected animals. Two assays were used for the detection of trypanosomal antibodies, one using specific anti-camel IgG conjugate and another using a non-specific Protein A conjugate. The third assay detected the presence of trypanosomal antigens using anti-T. evansi antibodies in a double antibody sandwich assay. Inspection of the frequency distribution of assay results suggested that the ELISA for circulating trypanosomal antibodies using specific antisera and the ELISA for circulating antigens can distinguish between non-infected camels and infected camels exhibiting patent infections or not. The ELISA using Protein A conjugate to bind non-specifically to camel immunoglobulin did not appear to discriminate between infected and non-infected animals
The distribution of extremal points of Gaussian scalar fields
We consider the signed density of the extremal points of (two-dimensional)
scalar fields with a Gaussian distribution. We assign a positive unit charge to
the maxima and minima of the function and a negative one to its saddles. At
first, we compute the average density for a field in half-space with Dirichlet
boundary conditions. Then we calculate the charge-charge correlation function
(without boundary). We apply the general results to random waves and random
surfaces. Furthermore, we find a generating functional for the two-point
function. Its Legendre transform is the integral over the scalar curvature of a
4-dimensional Riemannian manifold.Comment: 22 pages, 8 figures, corrected published versio
Analysis of multiply spliced transcripts in lymphoid tissue reservoirs of rhesus macaques infected with RT-SHIV during HAART.
Highly active antiretroviral therapy (HAART) can reduce levels of human immunodeficiency virus type 1 (HIV-1) to undetectable levels in infected individuals, but the virus is not eradicated. The mechanisms of viral persistence during HAART are poorly defined, but some reservoirs have been identified, such as latently infected resting memory CD4⁺ T cells. During latency, in addition to blocks at the initiation and elongation steps of viral transcription, there is a block in the export of viral RNA (vRNA), leading to the accumulation of multiply-spliced transcripts in the nucleus. Two of the genes encoded by the multiply-spliced transcripts are Tat and Rev, which are essential early in the viral replication cycle and might indicate the state of infection in a given population of cells. Here, the levels of multiply-spliced transcripts were compared to the levels of gag-containing RNA in tissue samples from RT-SHIV-infected rhesus macaques treated with HAART. Splice site sequence variation was identified during development of a TaqMan PCR assay. Multiply-spliced transcripts were detected in gastrointestinal and lymphatic tissues, but not the thymus. Levels of multiply-spliced transcripts were lower than levels of gag RNA, and both correlated with plasma virus loads. The ratio of multiply-spliced to gag RNA was greatest in the gastrointestinal samples from macaques with plasma virus loads <50 vRNA copies per mL at necropsy. Levels of gag RNA and multiply-spliced mRNA in tissues from RT-SHIV-infected macaques correlate with plasma virus load
Steep sharp-crested gravity waves on deep water
A new type of steady steep two-dimensional irrotational symmetric periodic
gravity waves on inviscid incompressible fluid of infinite depth is revealed.
We demonstrate that these waves have sharper crests in comparison with the
Stokes waves of the same wavelength and steepness. The speed of a fluid
particle at the crest of new waves is greater than their phase speed.Comment: 4 pages, 2 figures, submitted to Phys. Rev. Let
Distribution of nearest distances between nodal points for the Berry function in two dimensions
According to Berry a wave-chaotic state may be viewed as a superposition of
monochromatic plane waves with random phases and amplitudes. Here we consider
the distribution of nodal points associated with this state. Using the property
that both the real and imaginary parts of the wave function are random Gaussian
fields we analyze the correlation function and densities of the nodal points.
Using two approaches (the Poisson and Bernoulli) we derive the distribution of
nearest neighbor separations. Furthermore the distribution functions for nodal
points with specific chirality are found. Comparison is made with results from
from numerical calculations for the Berry wave function.Comment: 11 pages, 7 figure
Fermions, Gauge Theories, and the Sinc Function Representation for Feynman Diagrams
We extend our new approach for numeric evaluation of Feynman diagrams to
integrals that include fermionic and vector propagators. In this initial
discussion we begin by deriving the Sinc function representation for the
propagators of spin-1/2 and spin-1 fields and exploring their properties. We
show that the attributes of the spin-0 propagator which allowed us to derive
the Sinc function representation for scalar field Feynman integrals are shared
by fields with non-zero spin. We then investigate the application of the Sinc
function representation to simple QED diagrams, including first order
corrections to the propagators and the vertex.Comment: 10 pages, Latex, 9 figure
MScMS-II: an innovative IR-based indoor coordinate measuring system for large-scale metrology applications
According to the current great interest concerning large-scale metrology applications in many different fields of manufacturing industry, technologies and techniques for dimensional measurement have recently shown a substantial improvement. Ease-of-use, logistic and economic issues, as well as metrological performance are assuming a more and more important role among system requirements. This paper describes the architecture and the working principles of a novel infrared (IR) optical-based system, designed to perform low-cost and easy indoor coordinate measurements of large-size objects. The system consists of a distributed network-based layout, whose modularity allows fitting differently sized and shaped working volumes by adequately increasing the number of sensing units. Differently from existing spatially distributed metrological instruments, the remote sensor devices are intended to provide embedded data elaboration capabilities, in order to share the overall computational load. The overall system functionalities, including distributed layout configuration, network self-calibration, 3D point localization, and measurement data elaboration, are discussed. A preliminary metrological characterization of system performance, based on experimental testing, is also presente
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