1,989 research outputs found

    High-Definition Optical Coherence Tomography for the in vivo Detection of Demodex Mites

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    Background: Demodex mites are involved in different skin diseases and are commonly detected by skin scrape tests or superficial biopsies. A new high-definition optical coherence tomography (HD-OCT) with high lateral and axial resolution in a horizontal (en-face) and vertical (slice) imaging mode might offer the possibility of noninvasive and fast in vivo examination of demodex mites. Methods: Twenty patients with demodex-related skin diseases and 20 age- and gender-matched healthy controls were examined by HD-OCT. Mites per follicle and follicles per field of view were counted and compared to skin scrape tests. Results: HD-OCT images depicted mites in the en-face mode as bright round dots in groups of 3-5 mites per hair follicle. In the patients with demodex-related disease, a mean number of 3.4 mites per follicle were detected with a mean number of 2.9 infested follicles per area of view compared to a mean of 0.6 mites in 0.4 infested follicles in the controls. The skin scrape tests were negative in 21% of the patients. Conclusion: The innovative HD-OCT enables fast and noninvasive in vivo recognition of demodex mites and might become a useful tool in the diagnosis and treatment monitoring of demodex-related skin diseases. Copyright (C) 2012 S. Karger AG, Base

    Observational biases in Lagrangian reconstructions of cosmic velocity fields

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    Lagrangian reconstruction of large-scale peculiar velocity fields can be strongly affected by observational biases. We develop a thorough analysis of these systematic effects by relying on specially selected mock catalogues. For the purpose of this paper, we use the MAK reconstruction method, although any other Lagrangian reconstruction method should be sensitive to the same problems. We extensively study the uncertainty in the mass-to-light assignment due to luminosity incompleteness, and the poorly-determined relation between mass and luminosity. The impact of redshift distortion corrections is analyzed in the context of MAK and we check the importance of edge and finite-volume effects on the reconstructed velocities. Using three mock catalogues with different average densities, we also study the effect of cosmic variance. In particular, one of them presents the same global features as found in observational catalogues that extend to 80 Mpc/h scales. We give recipes, checked using the aforementioned mock catalogues, to handle these particular observational effects, after having introduced them into the mock catalogues so as to quantitatively mimic the most densely sampled currently available galaxy catalogue of the nearby universe. Once biases have been taken care of, the typical resulting error in reconstructed velocities is typically about a quarter of the overall velocity dispersion, and without significant bias. We finally model our reconstruction errors to propose an improved Bayesian approach to measure Omega_m in an unbiased way by comparing the reconstructed velocities to the measured ones in distance space, even though they may be plagued by large errors. We show that, in the context of observational data, a nearly unbiased estimator of Omega_m may be built using MAK reconstruction.Comment: 29 pages, 21 figures, 6 tables, Accepted by MNRAS on 2007 October 2. Received 2007 September 30; in original form 2007 July 2

    The scaling relation of early-type galaxies in clusters. II: Spectroscopic data for galaxies in eight nearby clusters

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    AIMS: We present in this work low and intermediate resolution spectroscopic data collected for 152 early type galaxies in 8 nearby clusters with z \leq 0.10. METHODS: We use low resolution data to produce the redshift and the K-correction for every individual galaxy, as well as to give their overall spectral energy distribution, and some spectral indicators, including the 4000\AA break, the Mg2_2 strength, and the NaD equivalent width.We have also obtained higher resolution data for early type galaxies in three of the clusters, to determine their central velocity dispersion. RESULTS: The effect of the resolution on the measured parameters is discussed. CONCLUSIONS: New accurate systemic redshift and velocity dispersion is presented for four of the surveyed clusters, A98, A3125, A3330, and DC2103-39. We have found that the K-correction values for E/S0 bright galaxies in a given nearby clusters are very similar. We also find that the distribution of the line indicators significantly differ from cluster to cluster.Comment: 16 pages, 9 figures, Accepted in A&

    The architecture of Abell 1386 and its relationship to the Sloan Great Wall

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    We present new radial velocities from AAOmega on the Anglo-Australian Telescope for 307 galaxies (b_J < 19.5) in the region of the rich cluster Abell 1386. Consistent with other studies of galaxy clusters that constitute sub-units of superstructures, we find that the velocity distribution of A1386 is very broad (21,000--42,000 kms^-1, or z=0.08--0.14) and complex. The mean redshift of the cluster that Abell designated as number 1386 is found to be ~0.104. However, we find that it consists of various superpositions of line-of-sight components. We investigate the reality of each component by testing for substructure and searching for giant elliptical galaxies in each and show that A1386 is made up of at least four significant clusters or groups along the line of sight whose global parameters we detail. Peculiar velocities of brightest galaxies for each of the groups are computed and found to be different from previous works, largely due to the complexity of the sky area and the depth of analysis performed in the present work. We also analyse A1386 in the context of its parent superclusters: Leo A, and especially the Sloan Great Wall. Although the new clusters may be moving toward mass concentrations in the Sloan Great Wall or beyond, many are most likely not yet physically bound to it.Comment: 21 pages, 9 figures, includes the full appendix table. Accepted for publication in MNRA

    Headache prevalence in the population of L’Aquila (Italy) after the 2009 earthquake

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    Stress induced by the events of daily life is considered a major factor in pathogenesis of primary tension-type headache. Little is known about the impact that could have a more stressful event, like a natural disaster, both in patients with chronic headache, both in people that do not had headache previously. The aim of the present study was to observe the prevalence of headache in the population following the devastating earthquake that affected the province of L’Aquila on April 6, 2009. The study population was conducted in four tent cities (Onna, Bazzano, Tempera-St. Biagio, Paganica). Sanitary access is recorded in the registers of medical triage, in the first 5 weeks, after the April 6, 2009. The prevalence of primary headache presentation was 5.53% (95% CI 4.2–7.1), secondary headache was 2.82% (95% CI 1.9–4.9). Pain intensity, assessed by Numerical Rating Scale score showed a mean value of 7 ± 1.1 (range 4–10). The drugs most used were the NSAIDs (46%) and paracetamol (36%), for impossibility of finding causal drugs. This study shows how more stressful events not only have an important role in determining acute exacerbation of chronic headache, but probably also play a pathogenic role in the emergence of primary headache. Also underlines the lack of diagnostic guidelines or operating protocols to early identify and treat headache in the emergency settings

    Reação de genótipos de Stylosanthes capitata à antracnose.

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    O Brasil detém o maior rebanho bovino comercial do mundo, baseado na utilização de pastagens. Atualmente, o uso de leguminosas forrageiras vem crescendo, em consorciação com poáceas ou exclusiva (bancos de proteínas), entre as quais Stylosanthes capitata Swartz. tem se destacado. Porém, sua utilização comercial tem sido limitada, em decorrência da antracnose, causada pelo fungo Colletotrichum gloeosporioides. Este trabalho teve como objetivo identificar genótipos de S. capitata com alto grau de resistência à antracnose. O trabalho foi desenvolvido na Embrapa Gado de Corte, de 2012 a 2014. Inicialmente, semearam-se 30 acessos de S. capitata em casa de vegetação, mantendo-se apenas uma planta por recipiente, onde estas permaneceram durante sete semanas até a realização da inoculação. Em delineamento de blocos ao acaso, em esquema fatorial (30 acessos do hospedeiro x quatro isolados do patógeno), com 10 repetições, conduziram-se dois experimentos, em épocas diferentes. Os isolados monospóricos de C. gloeosporioides (GC2, GC20, GC672 e GC722) foram selecionados com base na sua representatividade das raças fisiológicas mais frequentes no Brasil. Tais isolados foram inoculados com suspensões de 106 conídios/mL nos acessos hospedeiros. Baseado no grau de resistência ao patógeno, os acessos foram classificados como imune a altamente suscetível. No campo, em experimento em blocos ao acaso com quatro repetições, avaliaram-se a severidade da doença em 44 acessos da leguminosa. Dentre os genótipos inoculados, nos dois experimentos, os acessos GC1081, GC1087, GC1090, GC1094, GC1173 e GC2298 comportaram-se como resistentes a todos os isolados do patógeno estudados. Os isolados GC2 e GC672 foram os mais agressivos, independentemente do acesso do hospedeiro. Os resultados do experimento de campo evidenciaram a variabilidade genética do germoplasma estudado quanto à resistência a essa doença. No entanto, não foi possível selecionar acessos resistentes ao patógeno. Em tais condições, pode ocorrer nova variação fisiológica do patógeno, mais agressiva que aquelas artificialmente inoculadas. Temperatura e umidade relativa médias de 22-26º C e 77% UR, respectivamente, proporcionaram condições adequadas para a evolução da doença no campo

    Toward an internally consistent astronomical distance scale

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    Accurate astronomical distance determination is crucial for all fields in astrophysics, from Galactic to cosmological scales. Despite, or perhaps because of, significant efforts to determine accurate distances, using a wide range of methods, tracers, and techniques, an internally consistent astronomical distance framework has not yet been established. We review current efforts to homogenize the Local Group's distance framework, with particular emphasis on the potential of RR Lyrae stars as distance indicators, and attempt to extend this in an internally consistent manner to cosmological distances. Calibration based on Type Ia supernovae and distance determinations based on gravitational lensing represent particularly promising approaches. We provide a positive outlook to improvements to the status quo expected from future surveys, missions, and facilities. Astronomical distance determination has clearly reached maturity and near-consistency.Comment: Review article, 59 pages (4 figures); Space Science Reviews, in press (chapter 8 of a special collection resulting from the May 2016 ISSI-BJ workshop on Astronomical Distance Determination in the Space Age

    Cross Correlations of X-ray and Optically Selected Clusters With Near Infrared and Optical Galaxies

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    We compute the real-space cluster-galaxy cross-correlation xi_cg(r) using the ROSAT-ESO Flux Limited X-ray (REFLEX) cluster survey, a group catalogue constructed from the final version of the 2dFGRS, and galaxies extracted from 2MASS and APM surveys. This first detailed calculation of the cross-correlation for X-ray clusters and groups, is consistent with previous works and shows that xi_cg(r) can not be described by a single power law. We analyse the clustering dependence on the cluster X-ray luminosity L_X and virial mass M_vir thresholds as well as on the galaxy limiting magnitude. We also make a comparison of our results with those obtained for the halo-mass cross-correlation function in a LambdaCDM N-body simulation to infer the scale dependence of galaxy bias around clusters. Our results indicate that the distribution of galaxies shows a significant anti-bias at highly non-linear small cluster-centric distances (b_cg(r) ~ 0.7), irrespective of the group/cluster virial mass or X-ray luminosity and galaxy characteristics, which show that a generic process controls the efficiency of galaxy formation and evolution in high density regions. On larger scales b_cg(r) rises to a nearly constant value of order unity, the transition occuring at approximately 2 Mpch^(-1) for 2dF groups and 5 Mpch^(-1) for REFLEX clusters.Comment: 9 pages, 6 figures. Minor changes, replaced to match version accepted for publication in MNRA

    Charge separation relative to the reaction plane in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}}= 2.76 TeV

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    Measurements of charge dependent azimuthal correlations with the ALICE detector at the LHC are reported for Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}} = 2.76 TeV. Two- and three-particle charge-dependent azimuthal correlations in the pseudo-rapidity range η<0.8|\eta| < 0.8 are presented as a function of the collision centrality, particle separation in pseudo-rapidity, and transverse momentum. A clear signal compatible with a charge-dependent separation relative to the reaction plane is observed, which shows little or no collision energy dependence when compared to measurements at RHIC energies. This provides a new insight for understanding the nature of the charge dependent azimuthal correlations observed at RHIC and LHC energies.Comment: 12 pages, 3 captioned figures, authors from page 2 to 6, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/286
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