6,413 research outputs found
The Snowmelt-Runoff Model (SRM) user's manual
A manual to provide a means by which a user may apply the snowmelt runoff model (SRM) unaided is presented. Model structure, conditions of application, and data requirements, including remote sensing, are described. Guidance is given for determining various model variables and parameters. Possible sources of error are discussed and conversion of snowmelt runoff model (SRM) from the simulation mode to the operational forecasting mode is explained. A computer program is presented for running SRM is easily adaptable to most systems used by water resources agencies
Spin-triplet paired phases inside ferromagnet induced by Hund's rule coupling and electronic correlations: Application to
We discuss a mechanism of real-space spin-triplet pairing, alternative to
that due to quantum paramagnon excitations, and demonstrate its applicability
to . Both the Hund's rule ferromagnetic exchange and
inter-electronic correlations contribute to the same extent to the equal-spin
pairing, particularly in the regime in which the weak-coupling solution does
not provide any. The theoretical results, obtained within the
orbitally-degenerate Anderson lattice model, match excellently the observed
phase diagram for with the coexistent ferromagnetic (FM1) and
superconducting (-type) phase. Additionally, weak - and -type
paired phases appear in very narrow regions near the metamaganetic (FM2
FM1) and FM1 paramagnetic first-order
phase-transition borders, respectively. The values of magnetic moments in the
FM2 and FM1 states are also reproduced correctly in a semiquantitative manner.
The Hund's metal regime is also singled out as appearing near FM1-FM2 boundary
Analysis of standing vertical jumps using a force platform
A force platform analysis of vertical jumping provides an engaging demonstration of the kinematics and dynamics of one-dimensional motion. The height of the jump may be calculated (1) from the flight time of the jump, (2) by applying the impulse–momentum theorem to the force–time curve, and (3) by applying the work–energy theorem to the force-displacement curve
User's guide for the Nimbus 7 ERB Solar Analysis Tape (ESAT)
Five years of Nimbus 7 ERB solar data is available in compact form on a single ERB solar analysis tape (ESAT). The period covered is November 16, 1978 through October 31, 1983. The Nimbus 7 satellite performs just under 14 orbits a day and the ERB solar telescope observe the Sun once per orbit as the satellite passes + or - near the south pole. The data were carefully calibrated and screened. Mean orbital and daily values are given for the total solar irradiance plus selected spectral intervals. In addition, selected solar activity indicators are on the tape. The ERB experiment, the solar data calibration and screening procedures, the solar activity indicators, and the tape format are described briefly
Mechanical and Chemical Control of Smooth Cordgrass in Waillapa Bay, Washington
We evaluated four methods to control smooth cordgrass
(Spartina alterniflora Loisel), hereafter spartina, in Willapa
Bay, Washington: mowing, mowing plus herbicide combination,
herbicide only for clones, and aerial application of herbicide
for meadows. (PDF has 7 pages.
Triply Special Relativity
We describe an extension of special relativity characterized by {\it three}
invariant scales, the speed of light, , a mass, and a length .
This is defined by a non-linear extension of the Poincare algerbra, ,
which we describe here. For , becomes the Snyder
presentation of the -Poincare algebra, while for it
becomes the phase space algebra of a particle in deSitter spacetime. We
conjecture that the algebra is relevant for the low energy behavior of quantum
gravity, with taken to be the Planck mass, for the case of a nonzero
cosmological constant . We study the modifications of
particle motion which follow if the algebra is taken to define the Poisson
structure of the phase space of a relativistic particle.Comment: 13 page
Shape in an Atom of Space: Exploring quantum geometry phenomenology
A phenomenology for the deep spatial geometry of loop quantum gravity is
introduced. In the context of a simple model, an atom of space, it is shown how
purely combinatorial structures can affect observations. The angle operator is
used to develop a model of angular corrections to local, continuum flat-space
3-geometries. The physical effects involve neither breaking of local Lorentz
invariance nor Planck scale suppression, but rather reply on only the
combinatorics of SU(2) recoupling. Bhabha scattering is discussed as an example
of how the effects might be observationally accessible.Comment: 14 pages, 7 figures; v2 references adde
In situ studies of algal biomass in relation to physicochemical characteristics of the Salt Plains National Wildlife Refuge, Oklahoma, USA
This is the first in a series of experiments designed to characterize the Salt Plains National Wildlife Refuge (SPNWR) ecosystem in northwestern Oklahoma and to catalogue its microbial inhabitants. The SPNWR is the remnant of an ancient ocean, encompassing ~65 km(2 )of variably hypersaline flat land, fed by tributaries of the Arkansas River. Relative algal biomass (i.e., chlorophyll concentrations attributed to Chlorophyll-a-containing oxygenic phototrophs) and physical and chemical parameters were monitored at three permanent stations for a one-year period (July 2000 to July 2001) using a nested block design. Salient features of the flats include annual air temperatures that ranged from -10 to 40°C, and similar to other arid/semi-arid environments, 15–20-degree daily swings were common. Shade is absent from the flats system; intense irradiance and high temperatures (air and sediment surface) resulted in low water availability across the SPNWR, with levels of only ca. 15 % at the sediment surface. Moreover, moderate daily winds were constant (ca. 8–12 km h(-1)), sometimes achieving maximum speeds of up to 137 km h(-1). Typical of freshwater systems, orthophosphate (PO(4)(3-)) concentrations were low, ranging from 0.04 to <1 μM; dissolved inorganic nitrogen levels were high, but spatially variable, ranging from ca. 250–600 μM (NO(3)(- )+ NO(2)(-)) and 4–166 μM (NH(4)(+)). Phototroph abundance was likely tied to nutrient availability, with high-nutrient sites exhibiting high Chl-a levels (ca. 1.46 mg m(-2)). Despite these harsh conditions, the phototrophic microbial community was unexpectedly diverse. Preliminary attempts to isolate and identify oxygenic phototrophs from SPNWR water and soil samples yielded 47 species from 20 taxa and 3 divisions. Our data indicate that highly variable, extreme environments might support phototrophic microbial communities characterized by higher species diversity than previously assumed
Neutralizing antibody response during acute and chronic hepatitis C virus infection
Little is known about the role of Abs in determining the outcome of hepatitis C virus (HCV) infection. By using infectious retroviral pseudotypes bearing HCV glycoproteins, we measured neutralizing Ab (nAb) responses during acute and chronic HCV infection. In seven acutely infected health care workers, only two developed a nAb response that failed to associate with viral clearance. In contrast, the majority of chronically infected patients had nAbs. To determine the kinetics of strain-specific and crossreactive nAb emergence, we studied patient H, the source of the prototype genotype 1a H77 HCV strain. An early weak nAb response, specific for the autologous virus, was detected at seroconversion. However, neutralization of heterologous viruses was detected only between 33 and 111 weeks of infection. We also examined the development of nAbs in 10 chimpanzees infected with H77 clonal virus. No nAb responses were detected in three animals that cleared virus, whereas strain-specific nAbs were detected in six of the seven chronically infected animals after approximately 50 weeks of infection. The delayed appearance of high titer crossreactive nAbs in chronically infected patients suggests that selective mechanism(s) may operate to prevent the appearance of these Abs during acute infection. The long-term persistence of these nAbs in chronically infected patients may regulate viral replication
Evidence of sympathetic cooling of Na+ ions by a Na MOT in a hybrid trap
A hybrid ion-neutral trap provides an ideal system to study collisional
dynamics between ions and neutrals. This system provides a general cooling
method that can be applied to optically inaccessible species and can also
potentially cool internal degrees of freedom. The long range polarization
potentials () between ions and neutrals result in large
scattering cross sections at cold temperatures, making the hybrid trap a
favorable system for efficient sympathetic cooling of ions by collisions with
neutral atoms. We present experimental evidence of sympathetic cooling in a
hybrid trap of \ce{Na+} ions, which are closed shell and therefore do not have
a laser induced atomic transition, by equal mass cold Na atoms in a
magneto-optical trap (MOT).Comment: 7 figure
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