Ultra Wideband Channel Characterization and Ranging in Data Centers

This paper presents a detailed measurement based characterization of the Ultra Wideband (UWB) channels in a data center environment and examines the accuracy of direct ranging using Time of Arrival (ToA) measurements. Modern data centers present a unique indoor environment that to our knowledge has not yet been characterized. Our ranging experiments indicate that it is possible to achieve an accuracy of fraction of a meter via direct ranging and point to the feasibility of locating individual servers using more sophisticated cooperative ranging

The four-loop DRED gauge beta-function and fermion mass anomalous dimension for general gauge groups

We present four-loop results for the gauge beta-function and the fermion mass anomalous dimension for a gauge theory with a general gauge group and a multiplet of fermions transforming according to an arbitrary representation, calculated using the dimensional reduction scheme. In the special case of a supersymmetric theory we confirm previous calculations of both the gauge beta-function and the gaugino mass beta-function.Comment: 44 pages, added references (v2) minor changes (v3

Exciton-magnon transitions in the frustrated chromium antiferromagnets CuCrO2, alpha-CaCr2O4, CdCr2O4, and ZnCr2O4

We report on optical transmission spectroscopy of the Cr-based frustrated triangular antiferromagnets CuCrO2 and alpha-CaCr2O4, and the spinels CdCr2O4 and ZnCr2O4 in the near-infrared to visible-light frequency range. We explore the possibility to search for spin correlations far above the magnetic ordering temperature and for anomalies in the magnon lifetime in the magnetically ordered state by probing exciton-magnon sidebands of the spin-forbidden crystal-field transitions of the Cr3+ ions (spin S = 3/2). In CuCrO2 and alpha-CaCr2O4 the appearance of fine structures below T_N is assigned to magnon sidebands by comparison with neutron scattering results. The temperature dependence of the line width of the most intense sidebands in both compounds can be described by an Arrhenius law. For CuCrO2 the sideband associated with the 4A2 -> 2T2 transition can be observed even above T_N. Its line width does not show a kink at the magnetic ordering temperature and can alternatively be described by a Z2 vortex scenario proposed previously for similar materials. The exciton-magnon features in alpha-CaCr2O4 are more complex due to the orthorhombic distortion. While for CdCr2O4 magnon sidebands are identified below T_N and one sideband excitation is found to persist across the magnetic ordering transition, only a weak fine structure related to magnetic ordering has been observed in ZnCr2O4.Comment: 14 pages, 10 figures, all comments are welcome and appreciated, accepted for publication in PR

Lage ammoniakemissie ligboxenstal De M.e

Om de ammoniakemissie uit de ligboxenstal te verlagen neemt proefbedrijf De M.e allerlei maatregelen. De stal is bij de bouw voorzien van een dichte, hellende vloer met giergoot en de dieren krijgen een rantsoen op de DVE-norm met een lage OEB. Leveren deze maatregelen ook het gewenste effect op? Om die vraag te beantwoorden meet het Centrum voor Landbouw en Milieu op het proefbedrijf De M.e al enkele jaren de ammoniakemissie uit de ligboxenstal

Four-loop beta function and mass anomalous dimension in Dimensional Reduction

Within the framework of QCD we compute renormalization constants for the strong coupling and the quark masses to four-loop order. We apply the DR-bar scheme and put special emphasis on the additional couplings which have to be taken into account. This concerns the epsilon-scalar--quark Yukawa coupling as well as the vertex containing four epsilon-scalars. For a supersymmetric Yang Mills theory, we find, in contrast to a previous claim, that the evanescent Yukawa coupling equals the strong coupling constant through three loops as required by supersymmetry.Comment: 15 pages, fixed typo in Eq. (18

Bhat (Black Soybean): A traditional legume with high nutritional and nutraceutical properties from NW Himalayan region of India

307-319Bhat (black soybean) under the genus Glycine, is cultivated for food, fodder and medicinal uses by rural communities in Asia particularly, in China, Japan, Korea, Indonesia and India. In the Himalayan region of India, this legume is not only an integral part of a climate resilient farming system but also finds place in ethnodietary recipes and fondly consumed as a pulse. Black soybean ensures both food and nutritional security in hills where nutritional deficiencies are in abundance among rural, tribal and backward population engaged in subsistence farming in marginal rainfed terrains. Cultivation of black soybean is less capital intensive. Its ability to survive under harsh conditions particularly, in the event of failure of rain, makes it a better choice than other competitive crops grown during rainy season. Despite its enormous potentials, the legume has not gained the popularity in India and presently, area under this valuable legume is confined to North Himalayan hill region and scattered pockets of central India. Its high nutritive value, remedial and health promoting effects due to presence of various bioactive compounds make this legume an excellent functional food. Present review summarises the potential role of black soybean for human nutrition and health benefits