284 research outputs found
Evanescent incompressible strips as origin of the observed Hall resistance overshoot
In this work we provide a systematic explanation to the unusual non-monotonic
behavior of the Hall resistance observed at two-dimensional electron systems.
We use a semi-analytical model based on the interaction theory of the integer
quantized Hall effect to investigate the existence of the anomalous, \emph{i.e}
overshoot, Hall resistance . The observation of the overshoot resistance
at low magnetic field edge of the plateaus is elucidated by means of
overlapping evanescent incompressible strips, formed due to strong magnetic
fields and interactions. Utilizing a self-consistent numerical scheme we also
show that, if the magnetic field is decreased the decreases to its
expected value. The effects of the sample width, temperature, disorder strength
and magnetic field on the overshoot peaks are investigated in detail. Based on
our findings, we predict a controllable procedure to manipulate the maxima of
the peaks, which can be tested experimentally. Our model does not depend on
specific and intrinsic properties of the material, provided that a single
particle gap exists.Comment: A theoretical follow-up paper of arXiv:1007.258
Determination of Best management Practices anD innovations in Beef cattle farming anD their aDoPtion in the eastern meDiterranean region of turkey
abstract Boz, I., 2014. Determination of best management practices and innovations in beef cattle farming and their adoption in the Eastern Mediterranean region of Turkey. Bulg. J. Agric. Sci., The primary purpose of this study was to determine best management practices and innovations in beef cattle farming and their adoption in the Eastern Mediterranean Region of Turkey. A stratified random sample of 170 beef cattle farmers operated in the region was the participant of the study. Data were collected by administering a questionnaire filled during the face-to-face interviews conducted with each individual respondent. Results showed that adoption level was quite low and it was influenced by socioeconomic variables of cooperative membership, investments, farm size, owning improved breeds, and income; and by information-seeking variables of reading newspapers, using the Internet, contacts with extension personnel, and contacts with private veterinarians. It was concluded that governmental support for livestock sector had limited influence on the adoption of BMPs and innovations and therefore on the viability of beef cattle farming. The findings of this study are expected to provide useful information for scientists, policy-makers and extension organizations
Catalytic Dehydrogenation of Tetradecanol over Copper/Barium Oxide Catalysts
The liquid phase dehydrogenation of tetradecanol to tetradecanal has been studied over a series of CuO/BaO catalysts. Catalytic activity and selectivity to tetradecanal was found to depend on the ratio of easily reducible copper sites to less easily reducible copper sites. The catalysts have been characterized by X-ray diffraction, temperature programmed reduction, and thermo-gravimetric analysis. TPR results have shown that there were at least two types of copper oxides with varying reducibility. The relationship between the activity and area ratio of various copper oxide sites and a scheme for the conversion of tetradecanol were discussed
Muerte de un lince ibérico. Establecimiento de la causa y la autoría
Las ciencias forenses se aplican desde hace poco tiempo
como herramientas en las investigaciones de delitos contra el
medio ambiente. En este trabajo se expone un caso pionero en cuanto a la utilización de estas técnicas en un caso de un delit
o contra
la fauna silvestre.
La investigación se inicia tras la apari
ción de un lince ibérico muerto en el interior de una finca, donde se
encontraron también varios pollos supuestamente utilizados como cebos envenenados y otro cadáver, el de un zorro. El lince ib
érico
es uno de los mamíferos más amenazados del planeta.
Se
llevaron a cabo distintos análisis a partir de la necropsia de los cadáveres en
el Centro de Análisis y Diagnóstico de la Fauna Silvestre (CAD), el laboratorio de referencia para la fauna silvestre pertene
ciente a la
Junta de Andalucía. Los resultados fuer
on concluyentes, ambas muertes se produjeron como consecuencia de la ingestión de cebos
envenenados con un plaguicida extremadamente tóxico, el aldicarb. También se encontró esta sustancia en los pollos recogidos
en el
interior de la finca.
Con el fin de e
stablecer la culpabilidad de los propietarios de la finca, que negaron tener nada que ver con las
muertes y la colocación de los cebos, se utilizó una herramienta novedosa en este tipo de investigaciones, la genética forens
e. En
base a los resultados se co
nsiguió establecer una relación de parentesco entre los pollos utilizados como cebos envenenados y los
pollos propiedad reconocida de los sospechosos, que permitió demostrar que todos tenían el mismo origen.
Gracias al trabajo
conjunto y coordinado durante
toda la investigación y el informe pericial elaborado por el laboratorio del CAD, la Consejería de
Medio Ambiente y Organización del Territorio de la Junta de Andalucía consiguió una sentencia ejemplar contra los envenenador
es.The application of forensic science as a research tool to resolve crimes against the environment is relatively rec
ent. To our
knowledge this is the first instance in which the forensic genetic have been used as a definitive evidence to find out guilty
in crimes
against the wildlife.
Our research starts when an Iberian lynx was found dead into a farm; very close to sev
eral chickens used as
poisoned baits and a fox carcass. Iberian lynx is one of the most endangered mammals in the planet.
A comprehensive investigation
from the carcasses was performed in the Analysis and Diagnostic Center for Wildlife in Andalucia (CAD),
the reference laboratory
for wildlife of the Andalusian Government (Spain). The results determined that the deaths occurred as a result of ingestion o
f baits
poisoned with an extremely toxic pesticide, aldicarb. This substance was also found in chickens ga
thered inside the farm.
In order to establish the guilt of the owners of the farm, who refused to be related to the deaths and the placement of the b
aits, an
innovative tool was used in this kind of research, the forensic genetic.
Based on the results we
got, we established a relationship
between the chickens used as poisoned baits and the chickens from the farmer, all of them had the same origin.
Thanks to the
coordinated actuation during the complete investigation and the official report by the CAD labor
atory used in the trial, the Ministry
of Environmental and Territorial Organization got an exemplary sentence against the poisoners
Theoretical Investigation of Local Electron Temperature in Quantum Hall Systems
In this work we solve thermo-hydrodynamical equations considering a two
dimensional electron system in the integer quantum Hall regime, to calculate
the spatial distribution of the local electron temperature. We start from the
self-consistently calculated electrostatic and electrochemical potentials in
equilibrium. Next, by imposing an external current, we investigate the
variations of the electron temperature in the linear-response regime. Here a
local relation between the electron density and conductivity tensor elements is
assumed. Following the Ohm's law we obtain local current densities and by
implementing the results of the thermo-hydrodynamical theory, calculate the
local electron temperature. We observe that the local electron temperature
strongly depends on the formation of compressible and incompressible strips.Comment: 10 pages, 4 figure
Classical limit for the scattering of Dirac particles in a magnetic field
We present a relativistic quantum calculation at first order in perturbation
theory of the differential cross section for a Dirac particle scattered by a
solenoidal magnetic field. The resulting cross section is symmetric in the
scattering angle as those obtained by Aharonov and Bohm (AB) in the string
limit and by Landau and Lifshitz (LL) for the non relativistic case. We show
that taking pr_0\|sin(\theta/2)|/\hbar<<1 in our expression of the differential
cross section it reduces to the one reported by AB, and if additionally we
assume \theta << 1 our result becomes the one obtained by LL. However, these
limits are explicitly singular in \hbar as opposed to our initial result. We
analyze the singular behavior in \hbar and show that the perturbative Planck's
limit (\hbar -> 0) is consistent, contrarily to those of the AB and LL
expressions. We also discuss the scattering in a uniform and constant magnetic
field, which resembles some features of QCD
The Rare Decay D^0 -> gamma gamma
We present a calculation of the rare decay mode D^0 -> gamma gamma, in which
the long distance contributions are expected to be dominant. Using the Heavy
Quark Chiral Perturbation Theory Lagrangian with a strong g coupling as
recently determined by CLEO from the D^* -> D pi width, we consider both the
anomaly contribution which relates to the annihilation part of the weak
Lagrangian and the one-loop pi, K diagrams. The loop contributions which are
proportional to g and contain the a_1 Wilson coefficient are found to dominate
the decay amplitude, which turns out to be mainly parity violating. The
branching ratio is then calculated to be (1.0+-0.5)x10^(-8). Observation of an
order of magnitude larger branching ratio could be indicative of new physics.Comment: 16 pages, 5 figures, additional reference and several remarks added,
results unchange
Design evolution of the Giant Magellan Telescope Integral Field Spectrograph, GMTIFS
We report the design evolution for the GMT Integral Field Spectrograph, (GMTIFS). To support the range of operating modes – a spectroscopic channel providing integral field spectroscopy with variable spaxel scales, and a parallel imaging channel Nyquist sampling the LTAO corrected field of view - the design process has focused on risk mitigation for the demanding operational tolerances. We summarise results from prototype components, confirming concepts are meeting the necessary specifications. Ongoing review and simulation of the scientific requirements also leads to new demonstrations of the science that will be made possible with this new generation of high performance AO assisted instrumentation
Natalizumab, Fingolimod and Dimethyl Fumarate Use and Pregnancy-Related Relapse and Disability in Women With Multiple Sclerosis
To investigate pregnancy-related disease activity in a contemporary multiple sclerosis (MS) cohort
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