508 research outputs found
The Distribution of Amphipods in Southeastern Minnesota and Their Relation to Water Quality and Land Use
The distribution of the amphipods Gammarus pseudolimnaeus and Hyalella azteca was determined from 97 designated trout streams in Minnesota, along with temperature, conductivity, and nitrate levels. Streams were classified into 4 land use/geology groups. G. pseudolimnaeus was found in 11 counties and at 123 of 168 sites in 83 of the 97 streams sampled. Hyalella azteca was found in 7 counties at 26 sites m 21 streams. Spearman rank correlations showed a high degree of correlation between nitrate (range: 0-11 mg N/L), conductivity (range: 325-870 ÎĽS/cm), and geology. The relative abundance of G. pseudolimnaeus was negatively correlated with nitrate, geology groups, and H. azteca relative abundance; G. pseudolimnaeus was most common in low-order streams originating from diffuse springs, and H. Azteca was more common in larger streams. The distribution of G. pseudolimnaeus with its strong correlation to geology may be largely influenced by land use and it may be a good long-term indicator of water quality
Logarithmic conformal field theories and AdS correspondence
We generalize the Maldacena correspondence to the logarithmic conformal field
theories. We study the correspondence between field theories in
(d+1)-dimensional AdS space and the d-dimensional logarithmic conformal field
theories in the boundary of . Using this correspondence, we get the
n-point functions of the corresponding logarithmic conformal field theory in
d-dimensions.Comment: 10 pages, LaTeX. A paragraph was added. To appear in Int. J. Mod.
Phys.
Effects of Feeding Legume Silage With Differing Tannin Levels on Lactating Dairy Cattle
Condensed tannins (CT) bind to plant proteins in the rumen, reducing protein degradation to ammonia and increasing milk production and milk protein (e.g. Waghorn, 1987). Previous research showed that the reduced soluble non-protein nitrogen (NPN) content of red clover (Trifolium pratense) silage (RCS) was related to its greater N efficiency relative to lucerne (Medicago sativa) silage (LS) (Broderick et al., 2001). Commercial cultivars of birdsfoot trefoil (Lotus corniculatus; BFT) contain modest levels of CT which reduce NPN formation in silage (Albrecht & Muck, 1991). The objective was to compare silages made from BFT with RCS and LS for milk production and N efficiency in lactating dairy cows
Gravitino Propagator in anti de Sitter space
We construct the gauge invariant part of the propagator for the massless
gravitino in AdS(d+1) by coupling it to a conserved current. We also derive the
propagator for the massive gravitino.Comment: 24 pages; LaTe
Quarkonium from the Fifth Dimension
Adding fundamental matter of mass m_Q to N=4 Yang Mills theory, we study
quarkonium, and "generalized quarkonium" containing light adjoint particles. At
large 't Hooft coupling the states of spin<=1 are anomalously light (Kruczenski
et al., hep-th/0304032). We examine their form factors, and show these hadrons
are unlike any known in QCD. By a traditional yardstick they appear infinite in
size (as with strings in flat space) but we show that this is a failure of the
yardstick. All of the hadrons are actually of finite size ~ \sqrt{g^2N}/m_Q,
regardless of their radial excitation level and of how many valence adjoint
particles they contain. Certain form factors for spin-1 quarkonia vanish in the
large-g^2N limit; thus these hadrons resemble neither the observed J/Psi
quarkonium states nor rho mesons.Comment: 57 pages, LaTeX, 5 figure
Effect of Alfalfa Silage Storage Structure and Roasting Corn on Production and Ruminal Metabolism of Lactating Dairy Cows
Abstract The objective of this study was to determine if feeding roasted corn would improve production and nutrient utilization when supplemented to lactating cows fed 1 of 3 different alfalfa silages (AS). Forty-two lactating Holstein cows (6 fitted with ruminal cannulas) averaging 77 d in milk and 43kg of milk/d pretrial were assigned to 2 cyclic changeover designs. Treatments were AS ensiled in bag, bunker, or O 2 -limiting tower silos and supplemented with ground shelled corn (GSC) or roasted GSC (RGSC). Silages were prepared from second-cutting alfalfa, field-wilted an average of 24h, and ensiled over 2 d. Production and N utilization were evaluated in 36 cows during four 28-d periods, and ruminal fermentation was evaluated with 6 cows during five 21-d periods. Experimental diets contained 40% AS, 15% corn silage, and 35% of either GSC or RGSC on a dry matter basis. No significant interactions between AS and corn sources were detected for any production trait. Although the chemical composition of the 3 AS was similar, feeding AS from the O 2 -limited tower silo elicited positive production responses. Yields of 3.5% fat-corrected milk and fat were increased 1.7kg/d and 150g/d, and milk fat content was increased 0.3% when cows were fed diets based on AS from the O 2 -limiting silo compared with the other 2 silages. The responses in milk fat were paralleled by an average increase in acid detergent fiber digestibility of 270g/d for cows fed AS from the O 2 -limiting tower silo. However, ruminal concentrations of lipogenic volatile fatty acids were unchanged with AS source. Cows fed RGSC consumed 0.6kg/d more dry matter and yielded 30g/d more protein and 50g/d more lactose than cows fed GSC diets. There was no evidence of increased total tract digestibility of organic matter or starch, or reduced ruminal NH 3 concentration, when feeding RGSC. Free amino acids increased, and isovalerate decreased in rumen fluid from cows fed RGSC diets. However, responses in production with roasted corn were mainly due to increased dry matter intake, which increased the supply of energy and nutrients available for synthesis of milk and milk components
Holographic Normal Ordering and Multi-particle States in the AdS/CFT Correspondence
The general correlator of composite operators of N=4 supersymmetric gauge
field theory is divergent. We introduce a means for renormalizing these
correlators by adding a boundary theory on the AdS space correcting for the
divergences. Such renormalizations are not equivalent to the standard normal
ordering of current algebras in two dimensions. The correlators contain contact
terms that contribute to the OPE; we relate them diagrammatically to
correlation functions of compound composite operators dual to multi-particle
states.Comment: 18 pages, one equation corr., further comments and refs. adde
Recovery of the Schwarzschild Metric in Theories with Localized Gravity Beyond Linear Order
We solve the Einstein equations in the Randall-Sundrum framework with a
static, spherically symmetric matter distribution on the {\it physical brane}
and obtain an approximate expression for the gravitational field outside the
source to second order in the gravitational coupling. This expression when
confined on the {\it physical brane} coincides with the standard form of the
Schwarzschild metric. Therefore, the Randall-Sundrum scenario is consistent
with the Mercury precession test of General Relativity.Comment: 17 pages, plain Tex, references added, typos correcte
Strong tree level unitarity violations in the extra dimensional Standard Model with scalars in the bulk
We show how the tree level unitarity violations of compactified extra
dimensional extensions of the Standard Model become much stronger when the
scalar sector is included in the bulk. This effect occurs when the couplings
are not suppressed for larger Kaluza-Klein levels, and could have relevant
consequences for the phenomenology of the next generation of colliders. We also
introduce a simple and generic formalism to obtain unitarity bounds for finite
energies, taking into account coupled channels including the towers of
Kaluza-Klein excitations.Comment: Version to appear in Phys. Rev. D Typos corrected and remarks added
to clarify figure
Unitarity of Compactified Five Dimensional Yang-Mills Theory
Compactified five dimensional Yang-Mills theory results in an effective
four-dimensional theory with a Kaluza-Klein (KK) tower of massive vector
bosons. We explicitly demonstrate that the scattering of the massive vector
bosons is unitary at tree-level for low energies, and analyze the relationship
between the unitarity violation scale in the KK theory and the
nonrenormalizability scale in the five dimensional gauge theory. In the
compactified theory, low-energy unitarity is ensured through an interlacing
cancellation among contributions from the relevant KK levels. Such
cancellations can be understood using a Kaluza-Klein equivalence theorem which
results from the geometric ``Higgs'' mechanism of compactification. In these
theories, the unitarity violation is delayed to energy scales higher than the
customary limit through the introduction of additional vector bosons rather
than Higgs scalars.Comment: 10 pages, 1 eps figure, discussion of deconstruction expanded,
version accepted for publication in PL
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