A Psychophysical Comparison of Two Methods for Adaptive Histogram Equalization

Adaptive histogram equalization (ahe) is a method for adaptive contrast enhancement of digital images propped by Pizer et. Al.. It has the properties that it is an automatic, reproducible method for the simultaneous viewing of contrast within a digital image with a large dynamic range. Recent experiments have show that in specific cases, there is no significant difference in the ability of ahe and linear intensity windowing to display grey-scale contrast. More recently, Pizer et al. have proposed a variant of ahe which limits the allowed contrast enhancement of the image. The contrast-limited adaptive histogram equalization (clahe) produces images in which the noise content of an image is nor excessively enhanced, but in which sufficient contrast is provided for the visualization of structures within the image. Images processed with clahe have a more natural appearance and facilitate the comparison of different areas of an image. However, the reduced contrast enhancement of clahe may hinder the ability of an observer to detect the presence of some significant grey-scale contrast. In this work, a psychophysical observer experiment was performed to determine if there is a significant difference in the ability of ahe and clahe to depict grey-scale contrast. Observers were presented with CT images of the chest processed with ahe and clahe into some of which subtle artificial lesions were introduced. The observers were asked to rate their confidence regarding the presence of the lesions; this rating-scale data was analyzed using Receiver Operating Characteristic curving techniques. These ROC curves were compared for significant differences in the observers\u27 performances. In this study, no difference was found in the abilities of ahe and clahe to depict contrast information

Detection of a Fully-resolved Compton Shoulder of the Iron K-alpha Line in the Chandra X-ray Spectrum of GX 301-2

We report the detection of a fully-resolved, Compton-scattered emission line in the X-ray spectrum of the massive binary GX 301-2 obtained with the High Energy Transmission Grating Spectrometer onboard the Chandra X-ray Observatory. The iron K-alpha fluorescence line complex observed in this system consists of an intense narrow component centered at an energy of E = 6.40 keV and a redward shoulder that extends down to ~6.24 keV, which corresponds to an energy shift of a Compton back-scattered iron K-alpha photon. From detailed Monte Carlo simulations and comparisons with the observed spectra, we are able to directly constrain the physical properties of the scattering medium, including the electron temperature and column density, as well as an estimate for the metal abundance.Comment: 13 pages, 4 figures, 1 table, accepted for publication in ApJ Lette

"Pseudosarcoma" in a pregnant woman

BACKGROUND: Intravascular fasciitis (IVF) is a rare benign condition characterised by reactive myofibroblastic proliferation arising from the superficial or deep fascia and involving arteries and/or veins. It is a distinct variant of the more common condition of nodular fasciitis, which possesses similar clinical and histological features to IVF, but lacks vascular invasion. A thorough review of the literature revealed 26 reported cases of IVF. CASE PRESENTATION: We report a case of IVF in a 16-week pregnant lady affecting the hypothenar eminence of the hand associated with the ulnar artery. CONCLUSION: The characteristic involvement of muscular arteries and veins by reactive myofibroblastic proliferation in IVF suggests a malignant component and often leads to an inappropriate diagnosis for this benign condition. We propose that hormone-related changes associated with pregnancy may play an important role in the aetiopathogenesis of this myofibroblastic lesion

A Gene Co-Expression Network in Whole Blood of Schizophrenia Patients Is Independent of Antipsychotic-Use and Enriched for Brain-Expressed Genes

Despite large-scale genome-wide association studies (GWAS), the underlying genes for schizophrenia are largely unknown. Additional approaches are therefore required to identify the genetic background of this disorder. Here we report findings from a large gene expression study in peripheral blood of schizophrenia patients and controls. We applied a systems biology approach to genome-wide expression data from whole blood of 92 medicated and 29 antipsychotic-free schizophrenia patients and 118 healthy controls. We show that gene expression profiling in whole blood can identify twelve large gene co-expression modules associated with schizophrenia. Several of these disease related modules are likely to reflect expression changes due to antipsychotic medication. However, two of the disease modules could be replicated in an independent second data set involving antipsychotic-free patients and controls. One of these robustly defined disease modules is significantly enriched with brain-expressed genes and with genetic variants that were implicated in a GWAS study, which could imply a causal role in schizophrenia etiology. The most highly connected intramodular hub gene in this module (ABCF1), is located in, and regulated by the major histocompatibility (MHC) complex, which is intriguing in light of the fact that common allelic variants from the MHC region have been implicated in schizophrenia. This suggests that the MHC increases schizophrenia susceptibility via altered gene expression of regulatory genes in this network

LSST Science Book, Version 2.0

A survey that can cover the sky in optical bands over wide fields to faint magnitudes with a fast cadence will enable many of the exciting science opportunities of the next decade. The Large Synoptic Survey Telescope (LSST) will have an effective aperture of 6.7 meters and an imaging camera with field of view of 9.6 deg^2, and will be devoted to a ten-year imaging survey over 20,000 deg^2 south of +15 deg. Each pointing will be imaged 2000 times with fifteen second exposures in six broad bands from 0.35 to 1.1 microns, to a total point-source depth of r~27.5. The LSST Science Book describes the basic parameters of the LSST hardware, software, and observing plans. The book discusses educational and outreach opportunities, then goes on to describe a broad range of science that LSST will revolutionize: mapping the inner and outer Solar System, stellar populations in the Milky Way and nearby galaxies, the structure of the Milky Way disk and halo and other objects in the Local Volume, transient and variable objects both at low and high redshift, and the properties of normal and active galaxies at low and high redshift. It then turns to far-field cosmological topics, exploring properties of supernovae to z~1, strong and weak lensing, the large-scale distribution of galaxies and baryon oscillations, and how these different probes may be combined to constrain cosmological models and the physics of dark energy.Comment: 596 pages. Also available at full resolution at http://www.lsst.org/lsst/sciboo

LSST: from Science Drivers to Reference Design and Anticipated Data Products

(Abridged) We describe here the most ambitious survey currently planned in the optical, the Large Synoptic Survey Telescope (LSST). A vast array of science will be enabled by a single wide-deep-fast sky survey, and LSST will have unique survey capability in the faint time domain. The LSST design is driven by four main science themes: probing dark energy and dark matter, taking an inventory of the Solar System, exploring the transient optical sky, and mapping the Milky Way. LSST will be a wide-field ground-based system sited at Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m effective) primary mirror, a 9.6 deg$^2$ field of view, and a 3.2 Gigapixel camera. The standard observing sequence will consist of pairs of 15-second exposures in a given field, with two such visits in each pointing in a given night. With these repeats, the LSST system is capable of imaging about 10,000 square degrees of sky in a single filter in three nights. The typical 5$\sigma$ point-source depth in a single visit in $r$ will be $\sim 24.5$ (AB). The project is in the construction phase and will begin regular survey operations by 2022. The survey area will be contained within 30,000 deg$^2$ with $\delta<+34.5^\circ$, and will be imaged multiple times in six bands, $ugrizy$, covering the wavelength range 320--1050 nm. About 90\% of the observing time will be devoted to a deep-wide-fast survey mode which will uniformly observe a 18,000 deg$^2$ region about 800 times (summed over all six bands) during the anticipated 10 years of operations, and yield a coadded map to $r\sim27.5$. The remaining 10\% of the observing time will be allocated to projects such as a Very Deep and Fast time domain survey. The goal is to make LSST data products, including a relational database of about 32 trillion observations of 40 billion objects, available to the public and scientists around the world.Comment: 57 pages, 32 color figures, version with high-resolution figures available from https://www.lsst.org/overvie

Salespeople’s Renqing Orientation, Self-esteem, and Selling Behaviors: An Empirical Study in Taiwan

The purpose of this study was to investigate how salespeople’s renqing orientation and self-esteem jointly affect their selling behavior. Data were obtained from a survey of salespeople from 17 pharmaceutical and consumer-goods companies in Taiwan (n = 216). Salespeople’s renqing orientation (i.e., their propensity to adhere to the accepted norm of reciprocity) compensates the negative effect of self-esteem on their selling behaviors, such as adaptive selling and hard work. Our study results underscore the critical role of the character trait of renqing orientation in a culture emphasizing a norm of reciprocity. Therefore, it would be useful to consider a strategy of recruiting salespeople with either a high self-esteem or a combination of high renqing orientation and low self-esteem. The existing literature of industrial/organizational psychology and marketing primarily relies on constructs that are derived from Western cultural contexts. However, the present paper extended these literatures by investigating the possible joint effects of self-esteem with a trait originated from the Chinese culture on salespeople’s selling behaviors

Cellular Immune Responses and Viral Diversity in Individuals Treated during Acute and Early HIV-1 Infection

Immune responses induced during the early stages of chronic viral infections are thought to influence disease outcome. Using HIV as a model, we examined virus-specific cytotoxic T lymphocytes (CTLs), T helper cells, and viral genetic diversity in relation to duration of infection and subsequent response to antiviral therapy. Individuals with acute HIV-1 infection treated before seroconversion had weaker CTL responses directed at fewer epitopes than persons who were treated after seroconversion. However, treatment-induced control of viremia was associated with the development of strong T helper cell responses in both groups. After 1 yr of antiviral treatment initiated in acute or early infection, all epitope-specific CTL responses persisted despite undetectable viral loads. The breadth and magnitude of CTL responses remained significantly less in treated acute infection than in treated chronic infection, but viral diversity was also significantly less with immediate therapy. We conclude that early treatment of acute HIV infection leads to a more narrowly directed CTL response, stronger T helper cell responses, and a less diverse virus population. Given the need for T helper cells to maintain effective CTL responses and the ability of virus diversification to accommodate immune escape, we hypothesize that early therapy of primary infection may be beneficial despite induction of less robust CTL responses. These data also provide rationale for therapeutic immunization aimed at broadening CTL responses in treated primary HIV infection