12,114 research outputs found
Estimations for the Single Diffractive production of the Higgs boson at the Tevatron and the LHC
The single diffractive production of the standard model Higgs boson is
computed using the diffractive factorization formalism, taking into account a
parametrization for the Pomeron structure function provided by the H1
Collaboration. We compute the cross sections at next-to-leading order accuracy
for the gluon fusion process, which includes QCD and electroweak corrections.
The gap survival probability () is also introduced to account for
the rescattering corrections due to spectator particles present in the
interaction, and to this end we compare two different models for the survival
factor. The diffractive ratios are predicted for proton-proton collisions at
the Tevatron and the LHC for the Higgs boson mass of = 120 GeV.
Therefore, our results provide updated estimations for the diffractive ratios
of the single diffractive production of the Higgs boson in the Tevatron and LHC
kinematical regimes.Comment: 20 pages, 6 figures, 3 table
Darth Fader: Using wavelets to obtain accurate redshifts of spectra at very low signal-to-noise
We present the DARTH FADER algorithm, a new wavelet-based method for
estimating redshifts of galaxy spectra in spectral surveys that is particularly
adept in the very low SNR regime. We use a standard cross-correlation method to
estimate the redshifts of galaxies, using a template set built using a PCA
analysis on a set of simulated, noise-free spectra. Darth Fader employs wavelet
filtering to both estimate the continuum & to extract prominent line features
in each galaxy spectrum. A simple selection criterion based on the number of
features present in the spectrum is then used to clean the catalogue: galaxies
with fewer than six total features are removed as we are unlikely to obtain a
reliable redshift estimate. Applying our wavelet-based cleaning algorithm to a
simulated testing set, we successfully build a clean catalogue including
extremely low signal-to-noise data (SNR=2.0), for which we are able to obtain a
5.1% catastrophic failure rate in the redshift estimates (compared with 34.5%
prior to cleaning). We also show that for a catalogue with uniformly mixed SNRs
between 1.0 & 20.0, with realistic pixel-dependent noise, it is possible to
obtain redshifts with a catastrophic failure rate of 3.3% after cleaning (as
compared to 22.7% before cleaning). Whilst we do not test this algorithm
exhaustively on real data, we present a proof of concept of the applicability
of this method to real data, showing that the wavelet filtering techniques
perform well when applied to some typical spectra from the SDSS archive. The
Darth Fader algorithm provides a robust method for extracting spectral features
from very noisy spectra. The resulting clean catalogue gives an extremely low
rate of catastrophic failures, even when the spectra have a very low SNR. For
very large sky surveys, this technique may offer a significant boost in the
number of faint galaxies with accurately determined redshifts.Comment: 22 pages, 15 figures. Accepted for publication in Astronomy &
Astrophysic
Evidence of Low-Temperature Superparamagnetism in Mn_{4}$ Nanoparticle Ensembles
Please refer to the abstract within the main body of the paper
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Use and cost of disease-modifying therapies by Sonya Slifka Study participants: has anything really changed since 2000 and 2009?
Background:Disease-modifying therapies benefit individuals with relapsing forms of multiple sclerosis, but their utility remains unclear for those without relapses. Objective:To determine disease-modifying therapy use and costs in 2009, compare use in 2009 and 2000, and examine compliance with evidence-based guidelines. Methods:We determined the extent and characteristics of disease-modifying therapy use by participants in the Sonya Slifka Longitudinal Multiple Sclerosis Study (Slifka) in 2000 (n=2156) and 2009 (n=2361) and estimated out-of-pocket and total (payer) costs for 2009. Two multivariable logistic regressions predicted disease-modifying therapy use. Results:Disease-modifying therapy use increased from 55.3% in 2000 to 61.5% in 2009. In 2009, disease-modifying therapy use was reported by 76.5% of participants with relapsing-remitting multiple sclerosis, 73.2% with progressive-relapsing multiple sclerosis, 62.5% with secondary progressive multiple sclerosis, and 41.8% with primary progressive multiple sclerosis. Use was significantly associated with relapsing-remitting multiple sclerosis, shorter duration of illness, one to two relapses per year, non-ambulatory symptoms, using a cane, younger age, higher family income, and having health insurance. Average annual costs in 2009 were US16,302-18,928 for payers. Conclusion:Use rates were highest for individuals with relapsing-remitting multiple sclerosis, but substantial for those with progressive courses although clinical trials have not demonstrated significant benefits for them
The new automated daily mortality surveillance system
The experience reported in an earlier Eurosurveillance issue on a fast method to evaluate the impact of the 2003 heatwave on mortality in Portugal, generated a daily mortality surveillance system (VDM) that has been operating ever since jointly with the Portuguese Heat Health Watch Warning System. This work describes the VDM system and how it evolved to become an automated system operating year-round, and shows briefly its potential using mortality data from January 2006 to June 2009 collected by the system itself. The new system has important advantages such as: rapid information acquisition, completeness (the entire population is included), lightness (very little information is exchanged, date of death, age, sex, place of death registration). It allows rapid detection of impacts (within five days) and allows a quick preliminary quantification of impacts that usually took several years to be done. These characteristics make this system a powerful tool for public health action. The VDM system also represents an example of inter-institutional cooperation, bringing together organisations from two different ministries, Health and Justice, aiming at improving knowledge about the mortality in the population
GORLIN-GOLTZ SYNDROME: A CASE REPORT
Introdução: O Síndrome de Gorlin-Goltz é uma condição hereditária autossómica dominante rara caracterizada por: carcinomas basocelulares, queratoquistos odontogénicos, depressões palmo-plantares, calcificações da foice cerebral e malformações esqueléticas. Associa-se também a meduloblastoma e outras neoplasias.
Caso Clínico: Adolescente de 11 anos, com antecedentes de macrocefalia. Referenciada à consulta de estomatologia por quistos mandibulares recidivantes. O exame anátomo-patológico revelou tratarem-se de queratoquistos odontogénicos, pelo que é encaminhada para a consulta de pediatria. Objetivamente,
apresentava macrocefalia e facies “gros seiro” com bossas frontais e hipertelorismo. Efetuou estudo genético, que detetou mutação do gene PTCH1, confirmando a suspeita clínica.
Discussão: Os queratoquistos odontogénicos são o achado mais representativo do síndrome de Gorlin-Goltz nas duas primeiras décadas de vida, sendo de extrema importância um elevado índice de suspeição por parte do pediatra, com especial relevância para as alterações minor. Após o estabelecimento do
diagnóstico, é necessária uma equipa multidisciplinar para um adequado seguimento e tratamento atempado.Introduction: The Gorlin-Goltz syndrome is a rare autosomal dominant inherited condition characterized by: basal cell carcinomas, odontogenic keratocysts, palmar or plantar pits, calcification of the falx cerebri and skeletal malformations. Medulloblastoma and other tumors are also associated with it.
Case report: An 11-year-old female, with a history of macrocephaly, was referred to the Stomatology Department for recurrent mandibular cyst. Histopathological exam revealed odontogenic keratocysts, so the patient was referred to the Pediatric Department. Physical examination revealed macrocephaly and
coarse face, with frontal bossing and hy pertelorism. The genetic study performed detected a mutation in PTCH1 gene, confirming the clinical suspicion.
Discussion: Odontogenic keratocysts are the most representative finding in Gorlin-Goltz Syndrome in the first two decades of life, therefore a high suspicion level is mandatory among pediatricians concerning detection of minor changes. After the diagnosis, a multidisciplinary team is required for adequate follow-up and timely treatment
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