361 research outputs found
Response to tilted magnetic fields in Bi2Sr2CaCu2O8 with columnar defects: Evidence for transverse Meissner effect
The transverse Meissner effect (TME) in the highly layered superconductor
Bi2Sr2CaCu2O(8+y) with columnar defects is investigated by transport
measurements. We present detailed evidence for the persistence of the
Bose-glass phase when H is tilted at an angle theta < theta_c (T) away from the
column direction: (i) the variable-range vortex hopping process for low
currents crosses over to the half-loops regime for high currents; (ii) in both
regimes near theta_c(T) the energy barriers vanish linearly with tan(theta) ;
(iii) the transition temperature is governed by T_{BG}(0) -T_{BG}(theta) sim
|tan(theta)|^{1/\nu_{\perp}} with \nu_{\perp}=1.0 +/- 0.1. Furthermore, above
the transition as theta->\theta_c+, moving kink chains consistent with a
commensurate-incommensurate transition scenario are observed. These results
thereby clearly show the existence of the TME for theta < theta_c(T).Comment: 4 pages, RevTeX, 5 EPS figure
Analysis of Energy Consumption Performance towards Optimal Radioplanning of Wireless Sensor Networks in Heterogeneous Indoor Environments
In this paper the impact of complex indoor environment in the deployment and energy consumption of a wireless sensor network infrastructure is analyzed. The variable nature of the radio channel is analyzed by means of deterministic in-house 3D ray launching simulation of an indoor scenario, in which wireless sensors, based on an in-house CyFi implementation, typically used for environmental monitoring, are located. Received signal power and current consumption measurement results of the in-house designed wireless motes have been obtained, stating that adequate consideration of the network topology and morphology lead to optimal performance and power consumption reduction. The use of radioplanning techniques therefore aid in the deployment of more energy efficient elements, optimizing the overall performance of the variety of deployed wireless systems within the indoor scenario
Effect of field tilting on the vortices in irradiated Bi-2212
We report on transport measurements in a Bi-2212 single crystal with columnar
defects parallel to the c-axis. The tilt of the magnetic field away from the
direction of the tracks is studied for filling factors f=B_z/B_phi<1. Near the
Bose Glass transition temperature T_BG, the angular scaling laws are verified
and we find the field independent critical exponents nu'=1.1 and z'=5.30.
Finally, above H_perpC we evidence the signature of a smectic-A like vortex
phase. These experimental results provide support for the Bose Glass theory.Comment: 2 pages LaTeX, 2 EPS figures, uses fleqn and espcrc2 style macros.
Submitted to Proceedings of M2S-HTSC-V
Bose-Glass behaviour in Bi_{2}Sr_{2}Ca_{1-x}Y_{x}Cu_{2}O_{8} crystals with columnar defects: experimental evidence for variable-range hopping
We report on vortex transport in Bi_{2}Sr_{2}Ca_{1-x}Y_{x}Cu_{2}O_{8}
crystals irradiated at different doses of heavy ions. We show evidence of a
flux-creep resistivity typical of a variable-range vortex hopping mechanism as
predicted by Nelson and Vinokur.Comment: 5 pages LaTeX2e (uses elsart.cls), 1 Encapsulated PostScript figur
Multiple time-scale approach for a system of Brownian particles in a non-uniform temperature field
The Smoluchowsky equation for a system of interacting Brownian particles in a
temperature gradient is derived from the Kramers equation by means of a
multiple time-scale method. The interparticle interactions are assumed to be
represented by a mean-field description. We present numerical results that
compare well with the theoretical prediction together with an extensive
discussion on the prescription of the Langevin equation in overdamped systems.Comment: 8 pages, 2 figure
Vegetal diamine oxidase alleviates histamine-induced contraction of colonic muscles
Excess of histamine in gut lumen generates a pronounced gastrointestinal discomfort, which may include diarrhea and peristalsis dysfunctions. Deleterious effects of histamine can be alleviated with antihistamine drugs targeting histamine receptors. However, many antihistamine agents come with various undesirable side effects. Vegetal diamine oxidase (vDAO) might be a relevant alternative owing to its histaminase activity. Mammalian intestinal mucosa contains an endogenous DAO, yet possessing lower activity compared to that of vDAO preparation. Moreover, in several pathological conditions such as inflammatory bowel disease and irritable bowel syndrome, this endogenous DAO enzyme can be lost or inactivated. Here, we tested the therapeutic potential of vDAO by focusing on the well-known effect of histamine on gut motility. Using ex vivo and in vitro assays, we found that vDAO is more potent than commercial anti-histamine drugs at inhibiting histamine-induced contraction of murine distal colon muscles. We also identified pyridoxal 5′-phosphate (the biologically active form of vitamin B6) as an effective enhancer of vDAO antispasmodic activity. Furthermore, we discovered that rectally administered vDAO can be retained on gut mucosa and remain active. These observations make administration of vDAO in the gut lumen a valid alternative treatment for histamine-induced intestinal dysfunctions
Textile characteristics of fiber from Huacaya alpacas (Vicugna pacos)
Fiber from alpacas represents a substantial component of economic output for South American countries. In this study it determined the textile characteristics of fibers obtained from Huacaya alpacas raised at the South American Camelids Research and Development Center-Lachocc (CRDC-Lachocc) located at The National University of Huancavelica (UNH). Fleece samples were obtained from the mid-side rib area of 74 white alpacas (42 females and 32 males) of varying ages. The Average Fiber Diameter (AFD), Standard Deviation of the Average Fiber Diameter (SDAFD), Fiber Diameter Coefficient of Variation (FDCV), Comfort Factor (CF) and Staple Length (SL) were measured as textile characteristics and related to sex and age group. Most of the fleece samples could be classified as baby alpaca fleece according to the Peruvian Technical Standard classification (231.301.2014). Sex had no influence on any textile characteristic (p > 0.05). Meanwhile, age affected only AFD and CF (p < 0.05). Together the results indicated that alpacas farmed at CRDC-Lachocc had good potential to produce high quality fibers
CALIOPE: supercomputing for air quality improvement
CALIOPE és un sistema de predicció de la qualitat de l’aire desenvolupat pel Departament de Ciències de la Terra del Barcelona Supercomputing Center - Centre Nacional de Supercomputació (BSC-CNS). Gràcies al potencial quant a tractament i anàlisi de dades que proporciona la supercomputació, CALIOPE ofereix pronòstics de la qualitat de l’aire per a Catalunya, la península Ibèrica i Europa, amb informació detallada sobre els principals contaminants regulats per les autoritats europees. A més, els propers mesos el sistema inclourà la simulació de Barcelona a escala urbana (CALIOPE Urban). Aquesta informació és fàcilment accessible des d’un web dirigit tant a gestors públics com a la ciutadania.Paraules clau: qualitat de l’aire, contaminació atmosfèrica, meteorologia, sistema de pronòstic, emissions, supercomputació.CALIOPE is the air quality forecast system developed by the Earth Sciences Department of Barcelona Supercomputing Center - Centre Nacional de Supercomputació (BSC-CNS). Thanks to the data processing and analysis potential that supercomputing provides, CALIOPE offers air quality forecasts for Catalonia, the Iberian Peninsula and Europe at large, with detailed information on the main pollutants regulated by the European authorities. In the next few months, the system will include Barcelona’s simulation on an urban scale (CALIOPE Urban). This information is easily accessible on a website so that both public administrations and citizens can consult it.Keywords: air quality, air pollution, meteorology, forecast system, emissions, supercomputing
An Exploration of the Ozone Dimer Potential Energy Surface
The (O3)2 dimer potential energy surface is thoroughly explored at the ab initio CCSD(T) computational level. Five minima are characterized with binding energies between 0.35 and 2.24 kcal/mol. The most stable may be characterized as slipped parallel, with the two O3 monomers situated in parallel planes. Partitioning of the interaction energy points to dispersion and exchange as the prime contributors to the stability, with varying contributions from electrostatic energy, which is repulsive in one case. Atoms in Molecules analysis of the wavefunction presents specific O⋯O bonding interactions, whose number is related to the overall stability of each dimer. All internal vibrational frequencies are shifted to the red by dimerization, particularly the antisymmetric stretching mode whose shift is as high as 111 cm−1. In addition to the five minima, 11 higher-order stationary points are identified
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