2,214 research outputs found

    Some effects of dust on photometry of high-z galaxies: Confounding the effects of evolution

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    Photometric observations of very distant galaxies--e.g., color vs. z or magnitude vs. z, have been used over the past decade or so in investigations into the evolution of the stellar component. Numerous studies have predicted significant color variations as a result of evolution, in addition to the shifting of different rest wavelengths into the band of observation. Although there is significant scatter, the data can be fit with relatively straightforward, plausible models for galaxian evolution. In very few cases are the effects of dust extinction included in the models. This is due in a large part to the uncertainty about the distribution and optical properties of the grains, and even whether or not they are present in significant numbers in some types of galaxies such as ellipticals. It is likely that the effects of dust on broadband observations are the greatest uncertainty in studies of very distant galaxies. We use a detailed Monte Carlo radiative transfer model within a spherical geometry for different star/dust distributions to examine the effects of dust on the broadband colors of galaxies as a function of redshift. The model fully accounts for absorption and angular redistribution in scattering. In this summary, we consider only the effects on color vs. redshift for three simple geometries each with the same total dust optical depth. Elsewhere at this conference, Capuano, Thronson, & Witt consider other effects of altering the relative dust/star distribution

    Star-dust geometries in galaxies: The effect of interstellar matter distributions on optical and infrared properties of late-type galaxies

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    The presence of substantial amounts of interstellar dust in late-type galaxies affects observable parameters such as the optical surface brightness, the color, and the ratio of far-infrared to optical luminosity of these galaxies. We conducted radiative transfer calculations for late-type galaxy environments to examine two different scenarios: (1) the effects of increasing amounts of dust in two fixed geometries with different star distributions; and (2) the effects of an evolving dust-star geometry in which the total amount of dust is held constant, for three different star distributions. The calculations were done for ten photometric bands, ranging from the far-ultraviolet to the near-infrared (K), and scattered light was included in the galactic surface brightness at each wavelength. The energy absorbed throughout these ten photometric bands was assumed to re-emerge in the far-infrared as thermal dust emission. We also considered the evolutionary contraction of a constant amount of dust relative to pre-existing star distributions

    Editorial: Endocrine modulators of neurological processes: potential treatment targets of pediatric neurological diseases.

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    Editorial on the Research Topic Endocrine Modulators of Neurological Processes: Potential Treatment Targets of Pediatric Neurological Diseases

    THE ANALYSIS OF OVER-DISPERSED COUNT DATA FROM A SINGLE FACTOR STUDY

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    Methods for analyzing over-dispersed count data in a one-way layout were compared using a Monte Carlo study. Several variance stabilizing transformations were examined as alternatives to analyzing the raw data using a general linear model. Additionally, generalized linear models were fit using a log link. For the generalized linear model, three approaches to account for over-dispersion were investigated: (1) a negative binomial distribution with known k, (2) a Poisson distribution with Pearson\u27s X2 as an estimate of the scale parameter, and (3) a Poisson distribution with over-dispersion estimated using the deviance. The analysis of the raw data and log transformed data controlled the size of the tests better than the generalized linear models in the region of the sample space studied

    Unicentric or multicentric castleman disease? A case report of a pelvic intraperitoneal mass in a middle aged woman

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    Castleman Disease is a lymphoid disorder characterized by the presence of an enlarged or abnormal lymph node/lymphatic tissue. The disease is classified into unicentric or multicentric variants. The unicentric form is a benign disorder that is usually asymptomatic and consists of a single lymphoid mass that is predominantly located in the mediastinum, but can also rarely develop in the neck or abdomen. The multicentric type involves more than one lymphatic station and is related to the presence of type B symptoms (fevers, night sweats and weight loss), HIV/HHV8 infection and increased serum IL-6 levels. We present the case of an unusual pelvic intraperitoneal manifestation of Castleman Disease in a 52-year-old caucasian woman who showed clinical, radiological, histological and laboratory findings common to both Unicentric and Multicentric Castleman Disease

    An Integrated Approach to Risk and Impacts of Geo-Resources Exploration and Exploitation

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    Geo-resources are widely exploited in our society, with huge benefits for both economy and communities. Nevertheless, with benefits come risks and impacts. Understanding how such risks and impacts are intrinsically borne in a given project is of critical importance for both industry and society. In particular, it is crucial to distinguish between the specific impacts related to exploiting a given energy resource and those shared with the exploitation of other energy resources. A variety of different approaches can be used to identify and assess such risks and impacts. In particular, Life Cycle Assessment (LCA) and risk assessments (RAs) are the most commonly adopted. Although both are widely used to support decision making in environmental management, they are rarely used in combination perhaps because they have been developed by largely different groups of specialists. By analyzing the structure and the ratio of the two tools, we have developed an approach for combining and harmonizing LCA and MRA; the resulting protocol envisages building MRA upon LCA both qualitatively and quantitatively. We demonstrate the approach in a case study using a virtual site (based on a real one) for geothermal energy production

    Stimulated single-fiber electromyography (sSFEMG) in Lambert-Eaton syndrome

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    Objective: To report the clinical features and the neurophysiological approach of a patient with Lambert-Eaton myasthenic syndrome (LEMS), highlighting the diagnostic role of the stimulated single fiber electromyography (sSFEMG). Case report: A 60-year-old woman presenting with the LEMS triad (proximal and axial weakness, autonomic dysfunction and areflexia) was evaluated by neurophysiological tests (electroneuromyography, repetitive stimulation test (TSR), voluntary and stimulated SFEMG). We reported: 1) increase of compound muscle action potential (CMAP) amplitude (>60%) following brief isometric exercise compared to the rest (baseline); 2) decremental/incremental response of CMAP amplitude at low- (3 Hz) and high-frequency (30 Hz) repetitive stimulation test (RST), respectively; 3) increased neuromuscular jitter and blocking at voluntary single-fiber electromyography (vSFEMG); 4) stimulation rate-dependent reduction of the neuromuscular jitter and blocking at sSFEMG. Diagnosis was confirmed by serological demonstration of circulating voltage gated calcium channels (VGCC) antibodies. Significance: The present case highlights the role of the sSFEMG in the diagnosis of LEMS, underling the stimulation rate-dependency of both neuromuscular jitter and blocks
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