672 research outputs found
Spectral Measurement of Watershed Coefficients in the Southern Great Plains
The author has identified the following significant results. It was apparent that the spectra calibration of runoff curve numbers cannot be achieved on watersheds where significant areas of timber were within the drainage area. The absorption of light by wet soil conditions restricts differentiation of watersheds with regard to watershed runoff curve numbers. It appeared that the predominant factor influencing the classification of watershed runoff curve numbers was the difference in soil color and its associated reflectance when dry. In regions where vegetation grown throughout the year, where wet surface conditions prevail or where watersheds are timbered, there is little hope of classifying runoff potential with visible light alone
Evapotranspiration of native vegetation in the closed basin of the San Luis Valley, Colorado
June 1987.Bibliography: page 21.Grant nos. 14-08-001-G895 and 14-08-0001-G1006; project no. 06; financed in part by the U.S. Department of the Interior, Geological Survey and Bureau of Reclamation, through the Colorado Water Resources Research Institute in cooperation with the U.S.D.A. Agricultural Research Service
Microrheology, stress fluctuations and active behavior of living cells
We report the first measurements of the intrinsic strain fluctuations of
living cells using a recently-developed tracer correlation technique along with
a theoretical framework for interpreting such data in heterogeneous media with
non-thermal driving. The fluctuations' spatial and temporal correlations
indicate that the cytoskeleton can be treated as a course-grained continuum
with power-law rheology, driven by a spatially random stress tensor field.
Combined with recent cell rheology results, our data imply that intracellular
stress fluctuations have a nearly power spectrum, as expected for
a continuum with a slowly evolving internal prestress.Comment: 4 pages, 2 figures, to appear in Phys. Rev. Let
Guided Neuronal Growth on Arrays of Biofunctionalized GaAs/InGaAs Semiconductor Microtubes
We demonstrate embedded growth of cortical mouse neurons in dense arrays of
semiconductor microtubes. The microtubes, fabricated from a strained
GaAs/InGaAs heterostructure, guide axon growth through them and enable
electrical and optical probing of propagating action potentials. The coaxial
nature of the microtubes -- similar to myelin -- is expected to enhance the
signal transduction along the axon. We present a technique of suppressing
arsenic toxicity and prove the success of this technique by overgrowing
neuronal mouse cells.Comment: 3 pages, 4 figure
Gravity of Monopole and String and Gravitational Constant in 3He-A
We discuss the effective metric produced in superfluid 3He-A by such
topological objects as radial disgyration and monopole. In relativistic
theories these metrics are similar to that of the local string and global
monopole correspondingly. But in 3He-A they have the negative angle deficit,
which corresponds to the negative mass of the topological objects. The
effective gravitational constant G in superfluid 3He-A, derived from the
comparison with relativistic theories, is inversely proportional to the square
of the gap amplitude Delta, which plays the part of the Planck energy cut-off.
G depends on temperature and increases with T, which corresponds to the vacuum
screening of the Newton's constant.Comment: Latex file, 10 pages, no figure
Max Schottelius : Pioneer in Pheochromocytoma
First descriptions of diseases attract tremendous interest because they reveal scientific insight even in retrospect. Max Schottelius, the pathologist contributing the first histological description of pheochromocytoma, remains anonymous. We reviewed the description by Schottelius and weighed the report in modern context. Schottelius described the classical diagnostic elements of pheochromocytoma, including the brown appearance after exposure to chromate-containing Mueller's fixative. This color change, known as chromaffin reaction, results fromoxidation of catecholamines and is reflected in the name pheochromocytoma, meaning dusky-colored chromate-positive tumor. Thus Schottelius performed the first known histochemical contribution to diagnosis, which is today standard with immunohistochemistry for chromogranin. Copyright (c) 2017 Endocrine Society This article has been published under the terms of the Creative Commons Attribution NonCommercial, No-Derivatives License (CC BY-NC-ND).Peer reviewe
Two-Dimensional Diffusion in the Presence of Topological Disorder
How topological defects affect the dynamics of particles hopping between
lattice sites of a distorted, two-dimensional crystal is addressed.
Perturbation theory and numerical simulations show that weak, short-ranged
topological disorder leads to a finite reduction of the diffusion coefficient.
Renormalization group theory and numerical simulations suggest that
longer-ranged disorder, such as that from randomly placed dislocations or
random disclinations with no net disclinicity, leads to subdiffusion at long
times.Comment: 10 pages, 6 figure
Outbreak of Marburg hemorrhagic fever among miners in Kamwenge and Ibanda Districts, Uganda, 2007
Marburg hemorrhagic fever was detected among 4 miners in Ibanda District, Uganda, from June through September, 2007. Infection was likely acquired through exposure to bats or bat secretions in a mine in Kamwenge District, Uganda, and possibly human-to-human transmission between some patients. We describe the epidemiologic investigation and the health education response
Renormalized field theory and particle density profile in driven diffusive systems with open boundaries
We investigate the density profile in a driven diffusive system caused by a
plane particle source perpendicular to the driving force. Focussing on the case
of critical bulk density we use a field theoretic renormalization
group approach to calculate the density as a function of the distance
from the particle source at first order in (: spatial
dimension). For we find reasonable agreement with the exact solution
recently obtained for the asymmetric exclusion model. Logarithmic corrections
to the mean field profile are computed for with the result for .Comment: 32 pages, RevTex, 4 Postscript figures, to appear in Phys. Rev.
Surface critical behavior of driven diffusive systems with open boundaries
Using field theoretic renormalization group methods we study the critical
behavior of a driven diffusive system near a boundary perpendicular to the
driving force. The boundary acts as a particle reservoir which is necessary to
maintain the critical particle density in the bulk. The scaling behavior of
correlation and response functions is governed by a new exponent eta_1 which is
related to the anomalous scaling dimension of the chemical potential of the
boundary. The new exponent and a universal amplitude ratio for the density
profile are calculated at first order in epsilon = 5-d. Some of our results are
checked by computer simulations.Comment: 10 pages ReVTeX, 6 figures include
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