921 research outputs found
Stream Insect Production as a Function of Alkalinity and Detritus Processing
The study was conducted to determine if aquatic insect production was significantly different between high and low alkalinity mountain streams and if any differences were associated with food availability factors. The major objectives included determining: (1) if annual production differences occur between high and low alkalinity streams; (2) if processing rates of terrestrial detritus differs between high and low alkalinity streams; (3) if detrital processing rates are related to stream insect productivities; (4) if primary productivity varies between high and low alkalinity streams; (5) if toxic effects or micronutrient limitations exist in high or low alkalinity streams that could limit insect survivals. A high alkalinity stream was defined as one having over 150 milligrams per liter average total alkalinity. Six study sites on four high alkalinity streams were located in the Wasatch National Forest near Logan in northern Utah. Six study sites on four low alkalinity streams were located in the Shoshone National Forest near Yellowstone National Park in northern Wyoming. Sites from each region were shown to not differ significantly for all physical parameters tested.
The mean annual production of 22 of the 29 invertebrate taxa analyzed were significantly higher in the high alkalinity streams, while 2 taxa were significantly more productive in the low alkalinity streams. The mean annual production of all taxa summed was significantly higher in the high alkalinity streams. All high alkalinity sites had significantly higher production than any low alkalinity site.
Alder leaf packs left open to allow invertebrate activity had a significantly higher rate of weight loss in the high alkalinity stream. Alder leaf packs placed inside fine mesh bags to exclude invertebrate activity showed no significant differences in weight loss when the experiments were terminated. The patterns of weight loss for these mesh packs did differ between the two stream types. In the high alkalinity stream, the leaves had a early rapid weight loss phase followed by a period of reduced weight loss. In the low alkalinity stream, the leaves experienced little weight loss during the early phase of the study but lost weight rapidly during the latter phase.
The survivorships of all taxa tested did not differ significantly between high and low alkalinity water.
Estimates of detrital inputs based on drift measurements and standing crops of detritus collected with invertebrate samples showed no significant differences between regions.
The following conclusions resulted from the study. The high alkalinity streams had a significantly much higher production of aquatic invertebrates than did the low alkalinity streams. The high alkalinity streams also had significantly higher standing crops of attached algae and faster processing of alder leaves. Algae and processed allochthonous detritus are two major food sources for many aquatic invertebrates. It is concluded that a major reason for the great difference in invertebrate production between the physically similar high and low alkalinity streams in this study was the availability difference of these two food sources. The insects in the high alkalinity streams had much more of both food types available to them so a much higher annal production of aquatic invertebrates was supported
Acute and late toxicities of radiotherapy for patients with discoid lupus erythematosus: a retrospective case-control study
Pattern scaling using ClimGen: monthly-resolution future climate scenarios including changes in the variability of precipitation
Development, testing and example applications of the pattern-scaling approach for generating future climate change projections are reported here, with a focus on a particular software application called âClimGenâ. A number of innovations have been implemented, including using exponential and logistic functions of global-mean temperature to represent changes in local precipitation and cloud cover, and interpolation from climate model grids to a finer grid while taking into account land-sea contrasts in the climate change patterns. Of particular significance is a new approach for incorporating changes in the inter-annual variability of monthly precipitation simulated by climate models. This is achieved by diagnosing simulated changes in the shape of the gamma distribution of monthly precipitation totals, applying the pattern-scaling approach to estimate changes in the shape parameter under a future scenario, and then perturbing sequences of observed precipitation anomalies so that their distribution changes according to the projected change in the shape parameter. The approach cannot represent changes to the structure of climate timeseries (e.g. changed autocorrelation or teleconnection patterns) were they to occur, but is shown here to be more successful at representing changes in low precipitation extremes than previous pattern-scaling methods
Successful treatment of a severely injured soldier from Afghanistan with pumpless extracorporeal lung assist and neurally adjusted ventilatory support
A variant approach to the overlap action
I describe an implementation of the overlap action, which is built from an
action which is itself an approximate overlap action. It appears to be about a
factor of 15-20 less expensive to use, than the usual overlap action with the
Wilson fermion action as its kernel. Ingredients include a fat link to suppress
coupling to dislocations and a free field action with a spectrum which
resembles an overlap; much of the gain comes from the use of eigenmodes of the
approximate action to begin the overlap calculation. As a physics example, I
compute the quark condensate in finite volume in the quenched approximation.Comment: 15 pages, Revtex, postscript figures. COLO-HEP-44
Finite-volume Correction to the Pion Decay Constant in the Epsilon-Regime
In the chiral limit of QCD, the pion decay constant F can be extracted from
lattice gauge theory by means of a coupling to isospin chemical potential. Here
we compute the leading correction due to finite volume in the epsilon-expansion
of chiral perturbation theory. A comparison is made to recent Monte Carlo data.Comment: 7 pages. Corrects an error in the published versio
Gluino Condensation in an Interacting Instanton Ensemble
We perform a semi-classical study of chiral symmetry breaking and of the
spectrum of the Dirac operator in QCD with adjoint fermions. For this purpose
we calculate matrix elements of the adjoint Dirac operator between instanton
zero modes and study their symmetry properties. We present simulations of the
instanton ensemble for different numbers of Majorana fermions in the adjoint
representation. These simulations provide evidence that instantons lead to
gluino condensation in supersymmetric gluodynamics.Comment: 32 pages, 5 figures, acknowledgment adde
Illinois Waterfowl Surveys and Investigations W-43-R-63 Annual Progress Report FY2016 Period: 1 July 2015 â 30 June 2016
Objectives
1) Inventory abundance and distribution of waterfowl and other waterbirds (a minimum of 10 species and guilds) during autumn migration at a minimum of 30 sites along the Illinois and central Mississippi rivers of Illinois,
2) Estimate waterfowl and other waterbird population sizes (a minimum of 10 species and guilds) during autumn migration using an aerial quadrat survey along the central Illinois River for comparison with aerial inventories (Objective 1),
3) Investigate the ecology of up to 50 gadwall and 50 American green-winged teal during spring migration in and near the central Illinois River valley of Illinois,
4) Determine breeding bird use of and nest density in a minimum of 10 moist-soil wetlands managed for waterfowl during summer in central Illinois,
5) Investigate the breeding ecology of a minimum of 50 sandhill cranes during spring and summer in northeastern Illinois consistent with an ongoing research project,
6) Investigate movements and home range size of a minimum of 10 Canada geese during winter in and near the Greater Chicago Metropolitan Area of Illinois, and
7) Determine habitat quality of a minimum of 100 wetlands and deepwater habitats during spring, summer, and early autumn for migrating dabbling ducks, breeding wetland birds, and migrating shorebirds in Illinois.Illinois Department of Natural Resources, Division of Wildlife & U.S. Fish and Wildlife Service Contract Number: RC09-13FWUIUCunpublishednot peer reviewedOpe
The Spectrum of the Dirac Operator in the Linear Sigma Model with Quarks
We derive the spectrum of the Dirac operator for the linear sigma-model with
quarks in the large N_c approximation using renormalization group flow
equations. For small eigenvalues, the Banks-Casher relation and the vanishing
linear term are recovered. We calculate the coefficient of the next to leading
term and investigate the spectrum beyond the low energy regime.Comment: 15 pages, 6 figures, to appear in Phys. Rev.
Nucleation and Growth of the Superconducting Phase in the Presence of a Current
We study the localized stationary solutions of the one-dimensional
time-dependent Ginzburg-Landau equations in the presence of a current. These
threshold perturbations separate undercritical perturbations which return to
the normal phase from overcritical perturbations which lead to the
superconducting phase. Careful numerical work in the small-current limit shows
that the amplitude of these solutions is exponentially small in the current; we
provide an approximate analysis which captures this behavior. As the current is
increased toward the stall current J*, the width of these solutions diverges
resulting in widely separated normal-superconducting interfaces. We map out
numerically the dependence of J* on u (a parameter characterizing the material)
and use asymptotic analysis to derive the behaviors for large u (J* ~ u^-1/4)
and small u (J -> J_c, the critical deparing current), which agree with the
numerical work in these regimes. For currents other than J* the interface
moves, and in this case we study the interface velocity as a function of u and
J. We find that the velocities are bounded both as J -> 0 and as J -> J_c,
contrary to previous claims.Comment: 13 pages, 10 figures, Revte
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