The X-ray CCD camera of the MAXI Experiment on the ISS/JEM

MAXI, Monitor of All-sky X-ray Image, is the X-ray observatory on the Japanese experimental module (JEM) Exposed Facility (EF) on the International Space Station (ISS). MAXI is a slit scanning camera which consists of two kinds of X-ray detectors: one is a one-dimensional position-sensitive proportional counter with a total area of $\sim 5000 cm^2$, the Gas Slit Camera (GSC), and the other is an X-ray CCD array with a total area $\sim 200 cm^2$, the Solid-state Slit Camera (SSC). The GSC subtends a field of view with an angular dimension of 1$^\circ\times 180^\circ$ while the SSC subtends a field of view with an angular dimension of 1$^\circ$ times a little less than 180$^\circ$. In the course of one station orbit, MAXI can scan almost the entire sky with a precision of 1$^\circ$ and with an X-ray energy range of 0.5-30 keV. We have developed the engineering model of CCD chips and the analogue electronics for the SSC. The energy resolution of EM CCD for Mn K$\alpha$ has a full-width at half maximum of $\simeq$ 182 eV. Readout noise is $\simeq$ 11 e^- rms.Comment: 10 pages, 4 figures Accepted for Nuclear Instruments and Method in Physics Researc

The Radial Structure of the Cygnus Loop Supernova Remnant --- Possible evidence of a cavity explosion ---

We observed the North-East (NE) Limb toward the center region of the Cygnus Loop with the ASCA Observatory. We found a radial variation of electron temperature (kTe) and ionization timescale (log(\tau)) whereas no variation could be found for the abundances of heavy elements. In this paper, we re-analyzed the same data set and new observations with the latest calibration files. Then we constructed the precise spatial variations of kTe, log(\tau), and abundances of O, Ne, Mg, Si, and Fe over the field of view (FOV). We found a spatial variation not only in kTe and in log(\tau) but also in most of heavy elements. As described in Miyata et al. (1994), values of kTe increase and those of log(\tau) decrease toward the inner region. We found that the abundance of heavy elements increases toward the inner region. The radial profiles of O, Ne, and Fe show clear jump structures at a radius of 0.9 Rs, where Rs is the shock radius. Outside of 0.9 Rs, abundances of all elements are constant. On the contrary, inside of 0.9 Rs, abundances of these elements are 20--30 % larger than those obtained outside of 0.9 Rs. The radial profile of kTe also shows the jump structure at 0.9 Rs. This means that the hot and metal rich plasma fills the volume inside of 0.9 Rs. We concluded that this jump structure was the possible evidence for the pre-existing cavity produced by the precursor. If the ejecta fills inside of 0.9 Rs, the total mass of the ejecta was roughly 4\Msun. We then estimated the main-sequence mass to be roughly 15\Msun, which supports the massive star in origin of the Cygnus Loop supernova remnant and the existence of a pre-existing cavity.Comment: 37 pages, 14 figures. Accepted for publication of Ap

Variants of C-C Motif Chemokine 22 (CCL22) Are Associated with Susceptibility to Atopic Dermatitis: Case-Control Studies

Atopic dermatitis (AD) is a common inflammatory skin disease caused by multiple genetic and environmental factors. AD is characterized by the local infiltration of T helper type 2 (Th2) cells. Recent clinical studies have shown important roles of the Th2 chemokines, CCL22 and CCL17 in the pathogenesis of AD. To investigate whether polymorphisms of the CCL22 gene affect the susceptibility to AD, we conducted association studies and functional studies of the related variants. We first resequenced the CCL22 gene and found a total of 39 SNPs. We selected seven tag SNPs in the CCL22 gene, and conducted association studies using two independent Japanese populations (1st population, 916 cases and 1,032 controls; 2nd population 1,034 cases and 1,004 controls). After the association results were combined by inverse variance method, we observed a significant association at rs4359426 (meta-analysis, combined P = 9.6×10−6; OR, 0.74; 95% CI, 0.65–0.85). Functional analysis revealed that the risk allele of rs4359426 contributed to higher expression levels of CCL22 mRNA. We further examined the allelic differences in the binding of nuclear proteins by electrophoretic mobility shift assay. The signal intensity of the DNA-protein complex derived from the G allele of rs223821, which was in absolute LD with rs4359426, was higher than that from the A allele. Although further functional analyses are needed, it is likely that related variants play a role in susceptibility to AD in a gain-of-function manner. Our findings provide a new insight into the etiology and pathogenesis of AD

Geographical Analysis of Scorpion Populations on Habitat Islands

We examined the population structure of sand scorpions (Paruroctonus mesaensis) by performing genetic and morphological analyses. Sand scorpions were expected to show large genetic distances among populations because they are limited to sandy habitats. However, allozyme analysis showed only moderate genetic differentiation among populations. The morphological analysis showed a geographical association among regional sites. A positive association was found among genetic, morphological and geographical distance matrices. However, the morphological distance matrix showed a higher correlation value with geographical distance than with genetic distance. This result suggests that local environmental conditions may affect scorpion morphology more than they affect genetic structure among populations. The sand scorpion population structure can be described as one with gene flow among populations in the middle of the range and increased isolation along the range boundaries. The major mechanism of genetic exchange is probably sand corridors that periodically connect different sand dune systems. As the age of the North American Sonoran Desert may be less than 10 000 years, it is also possible that isolation has not existed long enough to differentiate the populations to a greater extent. © 1995 The Genetical Society of Great Britain

A Test of the Central-Marginal Model Using Sand Scorpion Populations (Paruroctonus mesaensis, Vaejovidae)

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Species Delimitation and Morphological Divergence in the Scorpion <i>Centruroides vittatus</i> (Say, 1821): Insights from Phylogeography

<div><p>Scorpion systematics and taxonomy have recently shown a need for revision, partially due to insights from molecular techniques. Scorpion taxonomy has been difficult with morphological characters as disagreement exists among researchers with character choice for adequate species delimitation in taxonomic studies. Within the family Buthidae, species identification and delimitation is particularly difficult due to the morphological similarity among species and extensive intraspecific morphological diversity. The genus <i>Centruroides</i> in the western hemisphere is a prime example of the difficulty in untangling the taxonomic complexity within buthid scorpions. In this paper, we present phylogeographic, Ecological Niche Modeling, and morphometric analyses to further understand how population diversification may have produced morphological diversity in <i>Centruroides vittatus</i> (Say, 1821). We show that <i>C. vittatus</i> populations in the Big Bend and Trans-Pecos region of Texas, USA are phylogeographically distinct and may predate the Last Glacial Maximum (LGM). In addition, we suggest the extended isolation of Big Bend region populations may have created the <i>C. vittatus</i> variant once known as <i>C. pantheriensis</i>.</p></div

Genome Analyses of a New Mycoplasma Species from the Scorpion Centruroides vittatus

Arthropod Mycoplasma are little known endosymbionts in insects, primarily known as plant disease vectors. Mycoplasma in other arthropods such as arachnids are unknown. We report the first complete Mycoplasma genome sequenced, identified, and annotated from a scorpion, Centruroides vittatus, and designate it as Mycoplasma vittatus. We find the genome is at least a 683,827 bp single circular chromosome with a GC content of 42.7% and with 987 protein-coding genes. The putative virulence determinants include 11 genes associated with the virulence operon associated with protein synthesis or DNA transcription and ten genes with antibiotic and toxic compound resistance. Comparative analysis revealed that the M. vittatus genome is smaller than other Mycoplasma genomes and exhibits a higher GC content. Phylogenetic analysis shows M. vittatus as part of the Hominis group of Mycoplasma. As arthropod genomes accumulate, further novel Mycoplasma genomes may be identified and characterized

The Complete Mitochondrial Genome of the Scorpion Centruroides vittatus (Arachnida: Scorpiones)

The complete mitochondrial genome (mitogenome) of the Striped scorpion (Centruroides vittatus) was assembled from Illumina-based whole genome sequencing. The circular genome is 14,602 bp in length with 13 protein coding genes, 21 tRNA, two rRNAs, a translocation-inversion of tRNALeu compared to the horse shoe crab mitogenome, and the absence of tRNAAsp. The A + T content of the mitogenome is 68.1%. Our Bayesian and maximum likelihood phylogenetic analyses placed the C. vittatus mitogenome as a sister group of C. limpidus and nestled within the new world Buthids

Reduced Gene Flow in Two Common Headwater Fishes in the Ouachita Mountains: A Response to Stream Drying and In-steam Barriers

Stream drying and in-stream barriers can influence migration and recolonization, yet we know little about how these impact population genetics of fishes. We analyzed microsatellite DNA from two common headwater fishes, Longear Sunfish (Lepomis megalotis) and Highland Stoneroller (Campostoma spadiceum), to compare population genetics of fishes in streams with varying degrees of connectivity. We sampled perennial and intermittent streams including examples with and without anthropogenic structures (road crossings). An additional perennial stream with a large waterfall was added to examine potential effects of a natural structure. We collected between 24 and 30 individuals of each species from three equidistant locations along each of five study streams. We found that Longear Sunfish and Highland Stoneroller populations experienced greater reductions in gene flow along the intermittent streams than along the perennial streams. However, the greatest reduction in gene flow between sub-populations generally coincided with the presence of permanent in-stream structures. Our study highlighted how overall genetic connectivity of fish populations is reduced by stream drying and showed that these effects can be exacerbated by in-stream barriers