Toward Large-Area Sub-Arcsecond X-Ray Telescopes II

In order to advance significantly scientific objectives, future x-ray astronomy missions will likely call for x-ray telescopes with large aperture areas (approx. = 3 sq m) and fine angular resolution (approx. = 1"). Achieving such performance is programmatically and technologically challenging due to the mass and envelope constraints of space-borne telescopes and to the need for densely nested grazing-incidence optics. Such an x-ray telescope will require precision fabrication, alignment, mounting, and assembly of large areas (approx. = 600 sq m) of lightweight (approx. = 2 kg/sq m areal density) high-quality mirrors, at an acceptable cost (approx. = 1 M$/sq m of mirror surface area). This paper reviews relevant programmatic and technological issues, as well as possible approaches for addressing these issues-including direct fabrication of monocrystalline silicon mirrors, active (in-space adjustable) figure correction of replicated mirrors, static post-fabrication correction using ion implantation, differential erosion or deposition, and coating-stress manipulation of thin substrates

Genomic survey of the non-cultivatable opportunistic human pathogen, Enterocytozoon bieneusi

© 2009 The Authors. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PLoS Pathogens 5 (2009): e1000261, doi:10.1371/journal.ppat.1000261.Enterocytozoon bieneusi is the most common microsporidian associated with human disease, particularly in the immunocompromised population. In the setting of HIV infection, it is associated with diarrhea and wasting syndrome. Like all microsporidia, E. bieneusi is an obligate, intracellular parasite, but unlike others, it is in direct contact with the host cell cytoplasm. Studies of E. bieneusi have been greatly limited due to the absence of genomic data and lack of a robust cultivation system. Here, we present the first large-scale genomic dataset for E. bieneusi. Approximately 3.86 Mb of unique sequence was generated by paired end Sanger sequencing, representing about 64% of the estimated 6 Mb genome. A total of 3,804 genes were identified in E. bieneusi, of which 1,702 encode proteins with assigned functions. Of these, 653 are homologs of Encephalitozoon cuniculi proteins. Only one E. bieneusi protein with assigned function had no E. cuniculi homolog. The shared proteins were, in general, evenly distributed among the functional categories, with the exception of a dearth of genes encoding proteins associated with pathways for fatty acid and core carbon metabolism. Short intergenic regions, high gene density, and shortened protein-coding sequences were observed in the E. bieneusi genome, all traits consistent with genomic compaction. Our findings suggest that E. bieneusi is a likely model for extreme genome reduction and host dependence.This research was supported by National Institutes of Health (NIH) grants R21 AI064118 (DEA) and R21 AI52792 (ST). HGM was supported in part by NIH contracts HHSN266200400041C and HHSN2662004037C (Bioinformatics Resource Centers) and by the G. Unger Vetlesen Foundation

Iodine-125 brachytherapy for brain tumours - a review

Iodine-125 brachytherapy has been applied to brain tumours since 1979. Even though the physical and biological characteristics make these implants particularly attractive for minimal invasive treatment, the place for stereotactic brachytherapy is still poorly defined

Toward Large-Area Sub-Arcsecond X-Ray Telescopes

The future of x-ray astronomy depends upon development of x-ray telescopes with larger aperture areas (>1 sq m) and finer angular resolution(100 sq m) of lightweight (1 kg/sq m areal density) high quality mirrors-possibly entailing active (in-space adjustable) alignment and figure correction. This paper discusses relevant programmatic and technological issues and summarizes progress toward large area sub-arcsecond x-ray telescopes. Key words: X-ray telescopes, x-ray optics, active optics, electroactive devices, silicon mirrors, differential deposition, ion implantation

Gastrointestinal hemorrhage after laparoscopic gastric bypass

Gastrointestinal hemorrhage is a potential perioperative complication after Roux-en-Y gastric bypass. The surgeon performing laparoscopic gastric bypass should understand the need for early recognition and management of this complication, as it can be life-threatening. This paper discusses the incidence and clinical presentation of gastrointestinal hemorrhage, mechanisms for hemorrhage, management options, and possible methods of prevention

Gastrointestinal hemorrhage after laparoscopic gastric bypass

Gastrointestinal hemorrhage is a potential perioperative complication after Roux-en-Y gastric bypass. The surgeon performing laparoscopic gastric bypass should understand the need for early recognition and management of this complication, as it can be life-threatening. This paper discusses the incidence and clinical presentation of gastrointestinal hemorrhage, mechanisms for hemorrhage, management options, and possible methods of prevention

Development of Baseline Monthly Utility Models for Fort Hood, Texas

The Fort Hood Army base in central Texas has more than 5,200 buildings and can be considered as typical of large Department of Defense Army bases in the continental United States. The annual utility bill of the base exceeds $25 million. Baseline monthly models for electricity use, electricity demand, gas use, and water use for the three cantonment areas of Fort Hood have been developed. Such models can be used as screening tools for detecting changes in future utility bills and also to track/evaluate the extent to which Presidential Executive Order 12902, mandating 30% decrease in energy utility bills from 1985 to 2005, is being met. In this analysis, 1990 has been selected as the baseline year to illustrate the predictive capability of the models. Since ascertaining the uncertainty of our predictions is very important for meaningful evaluations, we have also presented the relevant equations for computing the 95% prediction intervals of the regression models and illustrated their use with measured data over the period of 1989-1993. This study also evaluated two different types of energy modeling software- the Princeton Scorekeeping method (PRISM) and EModel- in order to ascertain which is more appropriate for baseline modeling of large Army installations such as Fort Hood. It was found that the EModel software, which has more flexibility to handle different types of linear single variate change point models, gave more accurate modeling results