177,563 research outputs found
Tevatron - probing TeV-scale gravity today
No full textThe production of black holes at Tevatron and LHC in spacetimes with compactified space-like large extra dimensions is studied. Either black holes can already be observed in ¯ pp collisions at s = 1.8 TeV or the fundamental gravity scale has to be above 1.4 TeV. At LHC the creation of a large number of quasi-stable black holes is predicted, with lifetimes beyond several hundred fm/c. A cut-off in the high-PT jet cross section is shown to be a unique signature of black hole production. This signal is compared to the jet plus missing energy signature due to graviton production in the final state as proposed by the ATLAS collaboration
Varying the dietary supply of C and N to manipulate the manure composition of water buffalo heifers in Oman
No full textOptimizing the composition of manure has the potential to reduce nutrient losses to the environment and to increase crop yields. In this study the effect of dietary ratios of carbon (C) to nitrogen (N) and neutral detergent fibre (NDF) to soluble carbohydrates (SC) on faeces composition of water buffalo heifers was assessed. Two digestibility trials were conducted with 12 animals each, fed one control and four test diets composed to achieve (1) high C/N and high NDF/SC ratios (HH), (2) low C/N and low NDF/SC ratios (LL), (3) high C/N and low NDF/SC ratios (HL) and (4) low C/N and high NDF/SC (LH) ratios. Faecal C/N ratios were generally lower than dietary C/N ratios, but the reduction was especially large for high C/N ratio diets (HH=55 %, HL=51 %). Faecal N concentration was positively correlated (r(2) = 0.6; P < 0.001) with N intake, but the increase in faecal N was more pronounced for diets that supplied low amounts of N. Faecal NDF concentration was positively related to NDF intake (r(2) = 0.42; P < 0.001), as well as the faecal C/N ratio (r(2) = 0.3; P < 0.001). Results demonstrate that C/N ratio and NDF concentration of buffalo manure were affected by diet composition. Diets with high C/N ratio and low NDF/SC ratio are preferable with regard to manure quality, but may not satisfy the nutritional requirements of producing animals, since N concentration in these diets was low and fibre concentration simultaneously high
Particulate Rate of Passage and Faeces Quality of Water Buffalo Fed Diets Varying in Concentrations of Nitrogen and Structural and Non-structural Carbohydrates
No full textEffects of diet concentrations of carbon (C), nitrogen (N), neutral detergent fibre (NDF) and soluble carbohydrates (SC) on digesta passage and faeces quality were studied in water buffalo. Rhodes grass hay, soybean meal, wheat bran and maize were combined for a high C/N - high NDF/SC ratio (HH), low C/N - low NDF/SC ratio (LL), high C/N - low NDF/SC ratio (HL) and low C/N - high NDF/SC (LH) ratio. Diets were offered to four heifers each during 21 days adaptation and 7 days experimentation. When the experiment started animals received a pulse dose of ytterbium-marked fibre; particle passage was derived from a one-compartment age-dependent Gamma-2 model. Diet N concentration significantly affected faecal concentration of N (r= 0.82, P= 0.83, P<0.001). Ruminal particle passage (gimel) ranged from 0.033 h(-1) (HL) to 0.043 h(-1) (LL), and was significantly related to the N (r= -0.84, P<0.001) and C (r= -0.57, P<0.05) concentration of the diet. Total tract retention time was shortest (P <0.001) for diet LL. The results indicate that differences in diet quality entail significant quality differences in buffalo dung that are not annihilated by the species' very efficient digestion of fibrous feeds.Deutsche Forschungsgemeinschaf
Particulate Rate of Passage and Faeces Quality of Water Buffalo Fed Diets Varying in Concentrations of Nitrogen and Structural and Non-structural Carbohydrates
No full textEffects of diet concentrations of carbon (C), nitrogen (N), neutral detergent fibre (NDF) and soluble carbohydrates (SC) on digesta passage and faeces quality were studied in water buffalo. Rhodes grass hay, soybean meal, wheat bran and maize were combined for a high C/N - high NDF/SC ratio (HH), low C/N - low NDF/SC ratio (LL), high C/N - low NDF/SC ratio (HL) and low C/N - high NDF/SC (LH) ratio. Diets were offered to four heifers each during 21 days adaptation and 7 days experimentation. When the experiment started animals received a pulse dose of ytterbium-marked fibre; particle passage was derived from a one-compartment age-dependent Gamma-2 model. Diet N concentration significantly affected faecal concentration of N (r= 0.82, P= 0.83, P<0.001). Ruminal particle passage (gimel) ranged from 0.033 h(-1) (HL) to 0.043 h(-1) (LL), and was significantly related to the N (r= -0.84, P<0.001) and C (r= -0.57, P<0.05) concentration of the diet. Total tract retention time was shortest (P <0.001) for diet LL. The results indicate that differences in diet quality entail significant quality differences in buffalo dung that are not annihilated by the species' very efficient digestion of fibrous feeds.Deutsche Forschungsgemeinschaf
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Lepton flavor violating radion decays in the Randall-Sundrum scenario
No full textWe predict the branching ratios of the lepton flavor violating radion decays r --> e(+/-)mu(+/-), r --> e(+/-)tau(+/-) and r --> mu(+/-)tau(+/-) in the two Higgs doublet model, in the framework of the Randall-Sundrum scenario. We observe that their branching ratios are at most of the order of 10(-8), for small values of radion mass and they decrease with increasing values of mr. Among these processes, the r --> tau(+/-)mu(+/-) decay would be the most suitable one to measure its branching ratio
Brane-World Gravity
No full textThe observable universe could be a 1+3-surface (the “brane”) embedded in a 1+3+d-dimensional spacetime (the “bulk”), with Standard Model particles and fields trapped on the brane while gravity is free to access the bulk. At least one of the d extra spatial dimensions could be very large relative to the Planck scale, which lowers the fundamental gravity scale, possibly even down to the electroweak (∼ TeV) level. This revolutionary picture arises in the framework of recent developments in M theory. The 1+10-dimensional M theory encompasses the known 1+9-dimensional superstring theories, and is widely considered to be a promising potential route to quantum gravity. At low energies, gravity is localized at the brane and general relativity is recovered, but at high energies gravity “leaks” into the bulk, behaving in a truly higher-dimensional way. This introduces significant changes to gravitational dynamics and perturbations, with interesting and potentially testable implications for high-energy astrophysics, black holes, and cosmology. Brane-world models offer a phenomenological way to test some of the novel predictions and corrections to general relativity that are implied by M theory. This review analyzes the geometry, dynamics and perturbations of simple brane-world models for cosmology and astrophysics, mainly focusing on warped 5-dimensional brane-worlds based on the Randall–Sundrum models. We also cover the simplest brane-world models in which 4-dimensional gravity on the brane is modified at low energies – the 5-dimensional Dvali–Gabadadze–Porrati models. Then we discuss co-dimension two branes in 6-dimensional models
Varying the dietary supply of C and N to manipulate the manure composition of water buffalo heifers in Oman
No full textOptimizing the composition of manure has the potential to reduce nutrient losses to the environment and to increase crop yields. In this study the effect of dietary ratios of carbon (C) to nitrogen (N) and neutral detergent fibre (NDF) to soluble carbohydrates (SC) on faeces composition of water buffalo heifers was assessed. Two digestibility trials were conducted with 12 animals each, fed one control and four test diets composed to achieve (1) high C/N and high NDF/SC ratios (HH), (2) low C/N and low NDF/SC ratios (LL), (3) high C/N and low NDF/SC ratios (HL) and (4) low C/N and high NDF/SC (LH) ratios. Faecal C/N ratios were generally lower than dietary C/N ratios, but the reduction was especially large for high C/N ratio diets (HH=55 %, HL=51 %). Faecal N concentration was positively correlated (r(2) = 0.6; P < 0.001) with N intake, but the increase in faecal N was more pronounced for diets that supplied low amounts of N. Faecal NDF concentration was positively related to NDF intake (r(2) = 0.42; P < 0.001), as well as the faecal C/N ratio (r(2) = 0.3; P < 0.001). Results demonstrate that C/N ratio and NDF concentration of buffalo manure were affected by diet composition. Diets with high C/N ratio and low NDF/SC ratio are preferable with regard to manure quality, but may not satisfy the nutritional requirements of producing animals, since N concentration in these diets was low and fibre concentration simultaneously high
Radion phenomenology in the Randall Sundrum scenario
No full textPhenomenology of a radion (#phi#) in the Randall-Sundrum scenario is discussed. The radion couples to the trace of energy momentum tensor of the standard model with a strength suppressed only by a new scale (#LAMBDA#_#phi#) which is an order of the electroweak scale. In particular, the effective coupling of a radion to two gluons is enhanced due to the trace anomaly of QCD. Therefore, its production cross section at hadron colliders could be enhanced, and the dominant decay mode of a relatively light radion is #phi##->#gg, unlike the SM Higgs boson case. We also present constraints on the mass m_#phi# and the new scale #LAMBDA#_#phi# from the Higgs search limit at LEP, perturbative unitarity bound and the stability of the radion/Higgs potential under radiative corrections. (orig.)Available from TIB Hannover: RA 2999(01-033) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
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