104 research outputs found
Service Delivery Utilizing Wireless Technology Within The Air Traffic Control Communication And Navigation Domain To Improve Positioning Awareness
Current air traffic levels around the world have pushed the enterprise architecture deployed to support air traffic management to the breaking point. Technology limitations prevent expansion of the current solutions to handle rising utilization levels without adopting radically different information delivery approaches. Meanwhile, an architectural transition would present the opportunity to support business and safety requirements that are not currently addressable. The purpose of this research paper is to create a framework for more effectively sharing positioning information utilizing improved air traffic control navigation and communication systems
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A methodology to quantify the release of spent nuclear fuel from dry casks during security-related scenarios.
Assessing the risk to the public and the environment from a release of radioactive material produced by accidental or purposeful forces/environments is an important aspect of the regulatory process in many facets of the nuclear industry. In particular, the transport and storage of radioactive materials is of particular concern to the public, especially with regard to potential sabotage acts that might be undertaken by terror groups to cause injuries, panic, and/or economic consequences to a nation. For many such postulated attacks, no breach in the robust cask or storage module containment is expected to occur. However, there exists evidence that some hypothetical attack modes can penetrate and cause a release of radioactive material. This report is intended as an unclassified overview of the methodology for release estimation as well as a guide to useful resource data from unclassified sources and relevant analysis methods for the estimation process
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Guideline for bolted joint design and analysis : version 1.0.
This document provides general guidance for the design and analysis of bolted joint connections. An overview of the current methods used to analyze bolted joint connections is given. Several methods for the design and analysis of bolted joint connections are presented. Guidance is provided for general bolted joint design, computation of preload uncertainty and preload loss, and the calculation of the bolted joint factor of safety. Axial loads, shear loads, thermal loads, and thread tear out are used in factor of safety calculations. Additionally, limited guidance is provided for fatigue considerations. An overview of an associated Mathcad{copyright} Worksheet containing all bolted joint design formulae presented is also provided
SHROOM3 is downstream of the planar cell polarity pathway and loss-of-function results in congenital heart defects
Congenital heart disease (CHD) is the most common birth defect, and the leading cause of death due to birth defects, yet causative molecular mechanisms remain mostly unknown. We previously implicated a novel CHD candidate gene, SHROOM3, in a patient with CHD. Using a Shroom3 gene trap knockout mouse (Shroom3gt/gt) we demonstrate that SHROOM3 is downstream of the noncanonical Wnt planar cell polarity signaling pathway (PCP) and loss-of-function causes cardiac defects. We demonstrate Shroom3 expression within cardiomyocytes of the ventricles and interventricular septum from E10.5 onward, as well as within cardiac neural crest cells and second heart field cells that populate the cardiac outflow tract. We demonstrate that Shroom3gt/gt mice exhibit variable penetrance of a spectrum of CHDs that include ventricular septal defects, double outlet right ventricle, and thin left ventricular myocardium. This CHD spectrum phenocopies what is observed with disrupted PCP. We show that during cardiac development SHROOM3 interacts physically and genetically with, and is downstream of, key PCP signaling component Dishevelled 2. Within Shroom3gt/gt hearts we demonstrate disrupted terminal PCP components, actomyosin cytoskeleton, cardiomyocyte polarity, organization, proliferation and morphology. Together, these data demonstrate SHROOM3 functions during cardiac development as an actomyosin cytoskeleton effector downstream of PCP signaling, revealing SHROOM3’s novel role in cardiac development and CHD
The Astropy Problem
The Astropy Project (http://astropy.org) is, in its own words, "a community
effort to develop a single core package for Astronomy in Python and foster
interoperability between Python astronomy packages." For five years this
project has been managed, written, and operated as a grassroots,
self-organized, almost entirely volunteer effort while the software is used by
the majority of the astronomical community. Despite this, the project has
always been and remains to this day effectively unfunded. Further, contributors
receive little or no formal recognition for creating and supporting what is now
critical software. This paper explores the problem in detail, outlines possible
solutions to correct this, and presents a few suggestions on how to address the
sustainability of general purpose astronomical software
Exploring the symbiotic pangenome of the nitrogen-fixing bacterium Sinorhizobium meliloti
<p>Abstract</p> <p>Background</p> <p><it>Sinorhizobium meliloti </it>is a model system for the studies of symbiotic nitrogen fixation. An extensive polymorphism at the genetic and phenotypic level is present in natural populations of this species, especially in relation with symbiotic promotion of plant growth. AK83 and BL225C are two nodule-isolated strains with diverse symbiotic phenotypes; BL225C is more efficient in promoting growth of the <it>Medicago sativa </it>plants than strain AK83. In order to investigate the genetic determinants of the phenotypic diversification of <it>S. meliloti </it>strains AK83 and BL225C, we sequenced the complete genomes for these two strains.</p> <p>Results</p> <p>With sizes of 7.14 Mbp and 6.97 Mbp, respectively, the genomes of AK83 and BL225C are larger than the laboratory strain Rm1021. The core genome of Rm1021, AK83, BL225C strains included 5124 orthologous groups, while the accessory genome was composed by 2700 orthologous groups. While Rm1021 and BL225C have only three replicons (Chromosome, pSymA and pSymB), AK83 has also two plasmids, 260 and 70 Kbp long. We found 65 interesting orthologous groups of genes that were present only in the accessory genome, consequently responsible for phenotypic diversity and putatively involved in plant-bacterium interaction. Notably, the symbiosis inefficient AK83 lacked several genes required for microaerophilic growth inside nodules, while several genes for accessory functions related to competition, plant invasion and bacteroid tropism were identified only in AK83 and BL225C strains. Presence and extent of polymorphism in regulons of transcription factors involved in symbiotic interaction were also analyzed. Our results indicate that regulons are flexible, with a large number of accessory genes, suggesting that regulons polymorphism could also be a key determinant in the variability of symbiotic performances among the analyzed strains.</p> <p>Conclusions</p> <p>In conclusions, the extended comparative genomics approach revealed a variable subset of genes and regulons that may contribute to the symbiotic diversity.</p
Ultrastructural localization of carbonic anhydrase in gastric parietal cells with the immunoglobulin-enzyme bridge method
Ultrastructural immunostaining of carbonic anhydrase in gastric parietal cells was accomplished with the immunoglobulin-peroxidase bridge procedure applied to cryostat sections of fixed guinea-pig stomach prior to dehydration and embedment. Of a variety of fixatives tested, only freshly prepared paraformaldehyde buffered with calcium acetate provided both immunostaining and adequate preservation of ultrastructural morphology. Delipidization or exposure of specimens to detergent prior to staining enhanced the intensity of the immunostaining and increased the sensitivity of the method. Increased diaminobenzidine concentration in the peroxidase substrate appeared also to intensify the densification at the reactive site. Carbonic anhydrase was localized ultrastructurally with this pre-embedment immunobridge procedure in the hyaloplasm of gastric parietal cells and less consistently in the superficial surface epithelium. The basal portion of the parietal cells stained more intensely than the apical region and immunoreactivity appeared concentrated at the plasmalemma and around mitochondria.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42849/1/10735_2005_Article_BF01012020.pd
Genome-wide association identifies nine common variants associated with fasting proinsulin levels and provides new insights into the pathophysiology of type 2 diabetes.
OBJECTIVE: Proinsulin is a precursor of mature insulin and C-peptide. Higher circulating proinsulin levels are associated with impaired β-cell function, raised glucose levels, insulin resistance, and type 2 diabetes (T2D). Studies of the insulin processing pathway could provide new insights about T2D pathophysiology. RESEARCH DESIGN AND METHODS: We have conducted a meta-analysis of genome-wide association tests of ∼2.5 million genotyped or imputed single nucleotide polymorphisms (SNPs) and fasting proinsulin levels in 10,701 nondiabetic adults of European ancestry, with follow-up of 23 loci in up to 16,378 individuals, using additive genetic models adjusted for age, sex, fasting insulin, and study-specific covariates. RESULTS: Nine SNPs at eight loci were associated with proinsulin levels (P < 5 × 10(-8)). Two loci (LARP6 and SGSM2) have not been previously related to metabolic traits, one (MADD) has been associated with fasting glucose, one (PCSK1) has been implicated in obesity, and four (TCF7L2, SLC30A8, VPS13C/C2CD4A/B, and ARAP1, formerly CENTD2) increase T2D risk. The proinsulin-raising allele of ARAP1 was associated with a lower fasting glucose (P = 1.7 × 10(-4)), improved β-cell function (P = 1.1 × 10(-5)), and lower risk of T2D (odds ratio 0.88; P = 7.8 × 10(-6)). Notably, PCSK1 encodes the protein prohormone convertase 1/3, the first enzyme in the insulin processing pathway. A genotype score composed of the nine proinsulin-raising alleles was not associated with coronary disease in two large case-control datasets. CONCLUSIONS: We have identified nine genetic variants associated with fasting proinsulin. Our findings illuminate the biology underlying glucose homeostasis and T2D development in humans and argue against a direct role of proinsulin in coronary artery disease pathogenesis
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Z-inertial fusion energy: power plant final report FY 2006.
This report summarizes the work conducted for the Z-inertial fusion energy (Z-IFE) late start Laboratory Directed Research Project. A major area of focus was on creating a roadmap to a z-pinch driven fusion power plant. The roadmap ties ZIFE into the Global Nuclear Energy Partnership (GNEP) initiative through the use of high energy fusion neutrons to burn the actinides of spent fuel waste. Transmutation presents a near term use for Z-IFE technology and will aid in paving the path to fusion energy. The work this year continued to develop the science and engineering needed to support the Z-IFE roadmap. This included plant system and driver cost estimates, recyclable transmission line studies, flibe characterization, reaction chamber design, and shock mitigation techniques
Dynamics and free-surface geometry of turbulent liquid sheets
Turbulent liquid sheets have been proposed to protect solid structures in fusion power plants by attenuating damaging radiation. For the High-Yield Lithium-Injection Fusion Energy (HYLIFE-II) inertial fusion energy (IFE) power plant concept, arrays of molten-salt sheets form a sacrificial barrier between the fusion event and the chamber first wall while permitting target injection and ignition. Thick liquid protection can help make fusion energy commercially attractive by reducing chamber size and prolonging chamber lifetime. Establishing an experimental design database for this basic building block flow will provide valuable information about various thick liquid protection schemes and allow reactor designers to establish acceptable tolerances between chamber components.
Turbulent water sheets issuing downwards into ambient air were studied experimentally at Reynolds numbers of 53,000 ??0,000 and Weber numbers of 2,900 ??,000 based on average velocity and the short dimension of the nozzle exit ( and delta). Initial conditions were quantified by the streamwise (x) and transverse (z) velocity components using laser-Doppler velocimetry just upstream of the nozzle exit. Characterization of the mean free-surface position and free-surface fluctuations, or surface ripple, and estimation of the amount of mass ejected as droplets from the free surface were quantified in the near-field (within 25 and delta of the nozzle exit). Surface ripple and mean sheet geometry were determined directly from planar laser-induced fluorescence visualizations of the free surface. The droplets due to the turbulent breakup of the jet, termed here the hydrodynamic source term, were measured using a simple collection technique to within 1 and delta of the nominal free surface of the jet. The influence of various passive flow control techniques such as removing low-momentum fluid at the free surface (boundary-layer cutting) on sheet geometry, surface ripple, and turbulent breakup were also quantified. The data obtained in this research will allow designers of inertial fusion energy systems to identify the parameter ranges necessary for successful implementation of the thick liquid wall protection system.Ph.D.Committee Co-Chair: Minami Yoda; Committee Co-Chair: Said I. Abdel-Khalik; Committee Member: Cyrus K. Aidun; Committee Member: Donald R. Webster; Committee Member: Ralph W. Moir; Committee Member: S. Mostafa Ghiaasiaa
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