570 research outputs found
PACCE: Perl Algorithm to Compute Continuum and Equivalent Widths
We present Perl Algorithm to Compute continuum and Equivalent Widths (pacce).
We describe the methods used in the computations and the requirements for its
usage. We compare the measurements made with pacce and "manual" ones made using
iraf splot task. These tests show that for SSP models the equivalent widths
strengths are very similar (differences <0.2A) for both measurements. In real
stellar spectra, the correlation between both values is still very good, but
with differences of up to 0.5A. pacce is also able to determine mean continuum
and continuum at line center values, which are helpful in stellar population
studies. In addition, it is also able to compute the uncertainties in the
equivalent widths using photon statistics. The code is made available for the
community through the web at http://www.if.ufrgs.br/~riffel/software.html.Comment: 8 pages, 5 figures, accepted by Astrophysics and Space Scienc
The quantum J_{1}-J_{1'}-J_{2} spin-1/2 Heisenberg antiferromagnet: A variational method study
The phase transition of the quantum spin-1/2 frustrated Heisenberg
antiferroferromagnet on an anisotropic square lattice is studied by using a
variational treatment. The model is described by the Heisenberg Hamiltonian
with two antiferromagnetic interactions: nearest-neighbor (NN) with different
coupling strengths J_{1} and J_{1'} along x and y directions competing with a
next-nearest-neighbor coupling J_{2} (NNN). The ground state phase diagram in
the ({\lambda},{\alpha}) space, where {\lambda}=J_{1'}/J_{1} and
{\alpha}=J_{2}/J_{1}, is obtained. Depending on the values of {\lambda} and
{\alpha}, we obtain three different states: antiferromagnetic (AF), collinear
antiferromagnetic (CAF) and quantum paramagnetic (QP). For an intermediate
region {\lambda}_{1}<{\lambda}<1 we observe a QP state between the ordered AF
and CAF phases, which disappears for {\lambda} above some critical value
{\lambda}_{1}. The boundaries between these ordered phases merge at the quantum
critical endpoint (QCE). Below this QCE there is again a direct first-order
transition between the AF and CAF phases, with a behavior approximately
described by the classical line {\alpha}_{c}{\simeq}{\lambda}/2
The discontinuous nature of chromospheric activity evolution
Chromospheric activity has been thought to decay smoothly with time and,
hence, to be a viable age indicator. Measurements in solar type stars in open
clusters seem to point to a different conclusion: chromospheric activity
undergoes a fast transition from Hyades level to that of the Sun after about 1
Gyr of main--sequence lifetime and any decaying trend before or after this
transition must be much less significant than the short term variations.Comment: 6 pages, 1 figure, to be published in Astrophysics and Space Scienc
Green functions for generalized point interactions in 1D: A scattering approach
Recently, general point interactions in one dimension has been used to model
a large number of different phenomena in quantum mechanics. Such potentials,
however, requires some sort of regularization to lead to meaningful results.
The usual ways to do so rely on technicalities which may hide important
physical aspects of the problem. In this work we present a new method to
calculate the exact Green functions for general point interactions in 1D. Our
approach differs from previous ones because it is based only on physical
quantities, namely, the scattering coefficients, and , to construct .
Renormalization or particular mathematical prescriptions are not invoked. The
simple formulation of the method makes it easy to extend to more general
contexts, such as for lattices of general point interactions; on a line; on
a half-line; under periodic boundary conditions; and confined in a box.Comment: Revtex, 9 pages, 3 EPS figures. To be published in PR
Occasional Finding Of Neurological Disorders During Children Hearing Loss Evaluation Using The Abr
One of the most important applications of the Brainstem evoked response audiometry (ABR) is in the evaluation of hearing loss in children. Today the ABR is also indicated in the screening of cochleovestibular syndromes to detect retrocochlear lesions, to monitor patients in a coma (brain death), in monitoring the brainstem during skull base surgery, etc. Among the many BERA qualities, is its capacity to evaluate the neurophysiologic integrity of the auditory brainstem pathway. In doing so, sometimes while evaluating hearing function in children we are faced with ABR waves that suggest the presence of retrocochlear lesions (trace asymmetry, increased interpeak intervals), many times confirmed through image studies. These cases are seen as occasional findings of neurologic disorders during children hearing loss evaluation. In this study we report 2 cases of neurologic disorders diagnosed with the use of the ABR to evaluate hearing loss in children. © Revista Brasileira de Otorrinolaringologia. All Rights reserved.733424428Jewett, D.L., Romano, M.N., Williston, J.S., Human auditory evoked potentials: Possible brain stem components detected on the scalp (1970) Science, 167 (924), pp. 1517-1518Starr, A., Hamilton, A.E., Correlation between confirmed sites of neurological lesions and abnormalities of far-field auditory brainstem responses (1976) Electroencephalogr Clin Neurophysiol, 41 (6), pp. 595-608Levine, R.A., Gardner, J.C., Fullerton, B.C., Stufflebeam, S.M., Carlisle, E.W., Furst, M., Effects of multiple sclerosis brainstem lesions on sound lateralization and brainstem auditory evoked potentials (1993) Hear Res, 68 (1), pp. 73-88Moller, A.R., Jannetta, P.J., Auditory evoked potentials recorded intracranially from the brain stem in man (1982) Exp Neurol, 78 (1), pp. 144-157Hashimoto, I., Ishiyama, Y., Yoshimoto, T., Nemoto, S., Brain-stem auditory-evoked potentials recorded directly from human brain-stem and thalamus (1981) Brain, 104 (PART 4), pp. 841-859Anson, B., Donaldson, J., (1981) Surgical anatomy of the temporal bone, , 3rd ed. Philadelphia: W.B. Saunders;Sousa LCA, Piza MRT, Costa SS. Poster: Brainstem Evoked Auditory Potential (ABR) in Neurology and Neurosurgery: 99th Meeting of the American Academy of Otolaryngology- Head and Neck Surgery. New Orleans, USA, Setembro1995Sousa, L.C.A., Piza, M.R.T., Costa, S.S., Diagnosis of Menières Disease: Routine and Extended Tests (2002) Otolaryngol Clin North Am, , JuneMarangos, N., Maier, W., Merz, R., Laszig, R., Brainstem response in cerebellopontine angle tumors (2001) Otol Neurotol, 22 (1), pp. 95-99Haapaniemi, J., Laurikainen, E., Jahansson, R., Rinne, T., Varpula, M., Audiovestibular findings and location of na acoustic neuroma (2000) Eur Arch Otorhinolaryngol, 257 (4), pp. 237-241Costa, S.S., Sousa, L.C.A., Cruz, O.L.M., Colli, B.O., Andrade, M.J., Rollin, G.A.F.S., Schwannoma vestibular: Apresentação atípica (1995) J Bras Neurosurg, 6 (2), pp. 41-48Sousa LCA, Piza MRT, Costa SS, Ferez M, Colli BO. Electrophysiologic Monitoring (ABR) of Coma Status,: 99th Meeting of the American Academy of Otolaryngology. Head and Neck Surgery, New Orleans, USA1995Coser, P.L., Menon, A.D., Electrophysiological study of auditory pathways and the vestibular system in tumor pathology of the 8th cranial nerve and of the cerebellopontile angle (1981) Rev Laryngol Otol Rhinol (Bord), 102 (5-6), pp. 239-24
Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector
A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results
Haematological and biochemical parameters in Churra-da-Terra-Quente ewes from the northeast of Portugal
Hematological and biochemical parameters, including plasma electrolytes and thyroid hormones, were determined in 73 clinically healthy Churra-da-Terra-Quente ewes, a typical breed from the northeast of Portugal. The hemogram values were: erythrocytes 9.8±1.51012/L; haemoglobin 118.1±19.1g/L; haematocrit 40.8±5.9%; leukocytes 5.7±1.8109/L; and platelets 544.3±177.2109/L. The thrombin time was 17.3±1.7 seconds. The values of biochemical parameters were: total protein 76.4±6.1g/L; glucose 2.87±0.60mmol/L; total cholesterol 1.65±0.33mmol/L; aspartate aminotransferase 155.9±49.2U/L; alanine aminotransferase 23.2±9.6U/L; γ-glutamyl transferase 48.0±18.7U/L; total alkaline phosphatase 121.6±76.1U/L; glutamate dehydrogenase 6.4±3.7U/L; urea 7.32±2.22mmol/L; creatinine 123.0±54.1μmol/L; total calcium 2.53±0.25mmol/L; phosphorus 2.10±0.46mmol/L; magnesium 1.01±0.09mmol/L; sodium 152.04±3.65mmol/L; potassium 4.7±0.4mmol/L; ionized calcium 1.32±0.07mmol/L; total thyroxine 111.75±42.29nmol/L; total triiodothyronine 1.01±0.28nmol/L; free T4 11.93±1.78pmol/L; free T3 4.22±1.33pmol/L; and thyroid-stimulating hormone 0.18±0.19μIU/mL. Although differences among the Churra-da-Terra-Quente breed and other breeds may occur, the hematological and biochemical parameters, plasma electrolytes, and thyroid hormones, for this indigenous breed, were generally situated within the reference intervals previously reported for sheep
Screening and in silico characterization of prophages in Helicobacter pylori clinical strains
Publisher Copyright: © The AuthorsThe increase of antibiotic resistance calls for alternatives to control Helicobacter pylori, a Gram-negative bacterium associated with various gastric diseases. Bacteriophages (phages) can be highly effective in the treatment of pathogenic bacteria. Here, we developed a method to identify prophages in H. pylori genomes aiming at their future use in therapy. A polymerase chain reaction (PCR)-based technique tested five primer pairs on 74 clinical H. pylori strains. After the PCR screening, 14 strains most likely to carry prophages were fully sequenced. After that, a more holistic approach was taken by studying the complete genome of the strains. This study allowed us to identify 12 intact prophage sequences, which were then characterized concerning their morphology, virulence, and antibiotic-resistance genes. To understand the variability of prophages, a phylogenetic analysis using the sequences of all H. pylori phages reported to date was performed. Overall, we increased the efficiency of identifying complete prophages to 54.1 %. Genes with homology to potential virulence factors were identified in some new prophages. Phylogenetic analysis revealed a close relationship among H. pylori-phages, although there are phages with different geographical origins. This study provides a deeper understanding of H. pylori-phages, providing valuable insights into their potential use in therapy.proofinpres
Measurement of the correlation between flow harmonics of different order in lead-lead collisions at √sNN = 2.76 TeV with the ATLAS detector
Correlations between the elliptic or triangular flow coefficients vm (m=2 or 3) and other flow harmonics vn (n=2 to 5) are measured using √sNN=2.76 TeV Pb+Pb collision data collected in 2010 by the ATLAS experiment at the LHC, corresponding to an integrated luminosity of 7 μb−1. The vm−vn correlations are measured in midrapidity as a function of centrality, and, for events within the same centrality interval, as a function of event ellipticity or triangularity defined in a forward rapidity region. For events within the same centrality interval, v3 is found to be anticorrelated with v2 and this anticorrelation is consistent with similar anticorrelations between the corresponding eccentricities, ε2 and ε3. However, it is observed that v4 increases strongly with v2, and v5 increases strongly with both v2 and v3. The trend and strength of the vm−vn correlations for n=4 and 5 are found to disagree with εm−εn correlations predicted by initial-geometry models. Instead, these correlations are found to be consistent with the combined effects of a linear contribution to vn and a nonlinear term that is a function of v22 or of v2v3, as predicted by hydrodynamic models. A simple two-component fit is used to separate these two contributions. The extracted linear and nonlinear contributions to v4 and v5 are found to be consistent with previously measured event-plane correlations
Search for W′→tb→qqbb decays in pp collisions at √s=8 TeV with the ATLAS detector
A search for a massive W′ gauge boson decaying to a top quark and a bottom quark is performed with the ATLAS detector in pp collisions at the LHC. The dataset was taken at a centre-of-mass energy of √s=8 TeV and corresponds to 20.3 fb−1 of integrated luminosity. This analysis is done in the hadronic decay mode of the top quark, where novel jet substructure techniques are used to identify jets from high-momentum top quarks. This allows for a search for high-mass W′ bosons in the range 1.5–3.0 TeV. b-tagging is used to identify jets originating from b-quarks. The data are consistent with Standard Model background-only expectations, and upper limits at 95 % confidence level are set on the W′→tb cross section times branching ratio ranging from 0.16pb to 0.33pb for left-handed W′ bosons, and ranging from 0.10pb to 0.21pb for W′ bosons with purely right-handed couplings. Upper limits at 95 % confidence level are set on the W′-boson coupling to tb as a function of the W′ mass using an effective field theory approach, which is independent of details of particular models predicting a W′boson
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