121 research outputs found
Vibrational properties of amorphous silicon from tight-binding O(N) calculation
We present an O(N) algorithm to study the vibrational properties of amorphous
silicon within the framework of tight-binding approach. The dynamical matrix
elements have been evaluated numerically in the harmonic approximation
exploiting the short-range nature of the density matrix to calculate the
vibrational density of states which is then compared with the same obtained
from a standard O() algorithm. For the purpose of illustration, an
1000-atom model is studied to calculate the localization properties of the
vibrational eigenstates using the participation numbers calculation.Comment: 5 pages including 5 ps figures; added a figure and a few references;
accepted in Phys. Rev.
CDMS, Supersymmetry and Extra Dimensions
The CDMS experiment aims to directly detect massive, cold dark matter
particles originating from the Milky Way halo. Charge and lattice excitations
are detected after a particle scatters in a Ge or Si crystal kept at ~30 mK,
allowing to separate nuclear recoils from the dominating electromagnetic
background. The operation of 12 detectors in the Soudan mine for 75 live days
in 2004 delivered no evidence for a signal, yielding stringent limits on dark
matter candidates from supersymmetry and universal extra dimensions. Thirty Ge
and Si detectors are presently installed in the Soudan cryostat, and operating
at base temperature. The run scheduled to start in 2006 is expected to yield a
one order of magnitude increase in dark matter sensitivity.Comment: To be published in the proceedings of the 7th UCLA symposium on
sources and detection of dark matter and dark energy in the universe, Marina
del Rey, Feb 22-24, 200
QCD Corrections and Non-standard Three Vector Boson Couplings in Production at Hadron Colliders
The process p\,p\hskip-7pt\hbox{^{^{(\!-\!)}}} \rightarrow W^{+} W^{-} + X
\rightarrow \ell^+_1 \nu_1 \ell^-_2 \bar \nu_2 + X is calculated to for general and conserving couplings (). The prospects for probing the couplings in this reaction are
explored. The impact of QCD corrections and various
background processes on the observability of non-standard couplings in
production at the Tevatron and the Large Hadron Collider (LHC) is
discussed in detail. Sensitivity limits for anomalous couplings are
derived at next-to-leading order for the Tevatron and LHC center of mass
energies, and are compared to the bounds which can be achieved in other
processes. Unless a jet veto or a cut on the total transverse momentum of the
hadrons in the event is imposed, the QCD corrections and
the background from top quark production decrease the sensitivity of
p\,p\hskip-7pt\hbox{^{^{(\!-\!)}}} \rightarrow W^{+} W^{-} + X \rightarrow
\ell^+_1 \nu_1 \ell^-_2 \bar \nu_2 + X to anomalous couplings by a
factor two to five.Comment: REVTEX 3, 62 pages, 21 Figures (not included available upon request),
the postscript file of the complete paper is available at
ftp://ucdhep.ucdavis.edu/han/ww/ww_paper.p
Search for Neutral Higgs Bosons of the Minimal Supersymmetric Standard Model in e+e- Interactions at sqrt(s) up to 209 GeV
A search for the lightest neutral CP-even and neutral CP-odd Higgs bosons of
the Minimal Supersymmetric Standard Model is performed using 216.6 pb-1 of data
collected with the L3 detector at LEP at centre-of-mass energies between 203
and 209 GeV. No indication of a signal is found. Including our results from
lower centre-of-mass energies, lower limits on the Higgs boson masses are set
as a function of tan(beta) for several scenarios. For tan(beta) greater than
0.7 they are mh > 84.5 GeV and mA > 86.3 GeV at 95% confidence level
Search for Supersymmetry in Di-Photon Final States at sqrt{s} = 1.96 TeV
We report results of a search for supersymmetry (SUSY) with gauge-mediated
symmetry breaking in di-photon events collected by the D0 experiment at the
Fermilab Tevatron Collider in 2002--2006. In 1.1 fb of data, we find no
significant excess beyond the background expected from the standard model and
set the most stringent lower limits to date for a standard benchmark model on
the lightest neutralino and chargino masses of 125 GeV and 229 GeV,
respectively, at 95% confidence
Search for scalar top quarks in the acoplanar charm jets and missing transverse energy final state in collisions at TeV
We present a search for the pair production of scalar top quarks,
, using 995 pb of data collected in collisions
with the D0 detector at the Fermilab Tevatron Collider at
TeV. Both scalar top quarks are assumed to decay into a charm quark and a
neutralino (), where is the
lightest supersymmetric particle. This leads to a final state with two
acoplanar charm jets and missing transverse energy. We find the yield of such
events to be consistent with the standard model expectation, and exclude sets
of and masses at the 95% C.L. that
substantially extend the domain excluded by previous searches.Comment: 10 pages, 5 figures, submitted to Physics Letters
Preparing for Critical Infrastructure Breakdowns: The Limits of Crisis Management and the Need for Resilience
Prevalence and incidence of iron deficiency in European community-dwelling older adults: an observational analysis of the DO-HEALTH trial
Background and aim
Iron deficiency is associated with increased morbidity and mortality in older adults. However, data on its prevalence and incidence among older adults is limited. The aim of this study was to investigate the prevalence and incidence of iron deficiency in European community-dwelling older adults aged ≥ 70 years.
Methods
Secondary analysis of the DO-HEALTH trial, a 3-year clinical trial including 2157 community-dwelling adults aged ≥ 70 years from Austria, France, Germany, Portugal and Switzerland. Iron deficiency was defined as soluble transferrin receptor (sTfR) > 28.1 nmol/L. Prevalence and incidence rate (IR) of iron deficiency per 100 person-years were examined overall and stratified by sex, age group, and country. Sensitivity analysis for three commonly used definitions of iron deficiency (ferritin 1.5) were also performed.
Results
Out of 2157 participants, 2141 had sTfR measured at baseline (mean age 74.9 years; 61.5% women). The prevalence of iron deficiency at baseline was 26.8%, and did not differ by sex, but by age (35.6% in age group ≥ 80, 29.3% in age group 75–79, 23.2% in age group 70–74); P 1.5. Occurrences of iron deficiency were observed with IR per 100 person-years of 9.2 (95% CI 8.3–10.1) and did not significantly differ by sex or age group. The highest IR per 100 person-years was observed in Austria (20.8, 95% CI 16.1–26.9), the lowest in Germany (6.1, 95% CI 4.7–8.0). Regarding the other definitions of iron deficiency, the IR per 100 person-years was 4.5 (95% CI 4.0–4.9) for ferritin 1.5.
Conclusions
Iron deficiency is frequent among relatively healthy European older adults, with people aged ≥ 80 years and residence in Austria and Portugal associated with the highest risk
MAREJADAS RURALES Y LUCHA POR LA VIDA, VOL. I:CONSTRUCCIÓN SOCIOCULTURAL Y ECONÓMICA DEL CAMPO.
Este volumen incluye trabajos que abordan temáticas
que demuestran que el campo es una construcción sociocultural, por lo tanto,
el medio rural es diferenciado y está en constante cambio y adaptación a los
procesos globales y locales.
Son 19 trabajos divididos en dos secciones, la primera, denominada Nuevas
dinámicas sociales, económicas y culturales en el medio rural, está compuesta
por 8 capítulos, en esta sección se incluyen aquellos trabajos que analizan de
manera concreta los cambios perceptibles en las relaciones rurales y en las
actividades económicas; procesos como desagrarización y nuevas actividades
económicas son abordados aquí, así como propuestas metodológicas para el
estudio de lo rural considerando los cambios y adaptaciones que se registran
en los territorios.
La segunda sección, Resistencias y alternativas al modelo neoliberal en la
producción agrícola y alimentaria, está integrada por 11 trabajos que abordan
las diversas formas en que los campesinos y productores agrícolas resisten y
se adaptan a los cambios globales y a las modificaciones de política pública,
desde los mercados alternativos hasta la producción de nuevos cultivos que
generan un mercado nuevo a su producción, hasta las resistencias y defensa de
la milpa, las reflexiones que nos ofrecen dan idea de la diversidad de formas
en que la vida campesina se mantiene a pesar de todos los embates.INSTITUTO DE CIENCIAS AGROPECUARIAS Y RURALES (ICAR), UNIVERSIDAD DE GUADALAJARA, EL COLEGIO DE MICHOACÁN A.C., CUCOSTA SUR GRANA, FACULTAD DE ESTUDIOS SUPERIORES ACATLÁN-UNAM, ECOSU
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