A study of perpetual inventory systems

Thesis (M.B.A.)--Boston Universit

High definition systems in Japan

The successful implementation of a strategy to produce high-definition systems within the Japanese economy will favorably affect the fundamental competitiveness of Japan relative to the rest of the world. The development of an infrastructure necessary to support high-definition products and systems in that country involves major commitments of engineering resources, plants and equipment, educational programs and funding. The results of these efforts appear to affect virtually every aspect of the Japanese industrial complex. The results of assessments of the current progress of Japan toward the development of high-definition products and systems are presented. The assessments are based on the findings of a panel of U.S. experts made up of individuals from U.S. academia and industry, and derived from a study of the Japanese literature combined with visits to the primary relevant industrial laboratories and development agencies in Japan. Specific coverage includes an evaluation of progress in R&D for high-definition television (HDTV) displays that are evolving in Japan; high-definition standards and equipment development; Japanese intentions for the use of HDTV; economic evaluation of Japan's public policy initiatives in support of high-definition systems; management analysis of Japan's strategy of leverage with respect to high-definition products and systems

Gas accretion as the origin of chemical abundance gradients in distant galaxies

It has recently been suggested that galaxies in the early Universe can grow through the accretion of cold gas, and that this may have been the main driver of star formation and stellar mass growth. Because the cold gas is essentially primordial, it has a very low abundance of elements heavier than helium (metallicity). As it is funneled to the centre of a galaxy, it will lead the central gas having an overall lower metallicity than gas further from the centre, because the gas further out has been enriched by supernovae and stellar winds, and not diluted by the primordial gas. Here we report chemical abundances across three rotationally-supported star-forming galaxies at z~3, only 2 Gyr after the Big Bang. We find an 'inverse' gradient, with the central, star forming regions having a lower metallicity than less active ones, opposite to what is seen in local galaxies. We conclude that the central gas has been diluted by the accretion of primordial gas, as predicted by 'cold flow' models.Comment: To Appear in Nature Oct 14, 2010; Supplementary Information included her

Dispersal and survival rates of adult and juvenile Red-tailed tropicbirds (Phaethon rubricauda) exposed to potential contaminants

Annual survival and dispersal rates of adult and juvenile red-tailed tropicbirds were examined in connection with exposure to heavy metals. From 1990-2000 the incineration of a U.S. stockpile of chemical weapons stored at Johnston Atoll exposed nesting tropicbirds to increased levels of human disturbance, smoke stack emissions and potential leaks. Using a multi-state mark-recapture modeling approach, birds nesting in this site (downwind of the plant) were compared to those nesting in a reference site (upwind of the plant) with less human disturbance, no exposure to smoke stack emissions or other potential incineration emissions. We did not find any difference in survival of adults or juveniles when comparing the two sites. Adult breeding dispersal rates did not differ between the sites but we did find differences in the age-specific natal dispersal rates. Birds fledged from downwind areas were less likely to return to their natal area to nest and more likely to immigrate to the upwind area than vice-versa. This asymmetry in emigration rates is believed to be due to differing vegetation densities and has implications for vegetation management in relation to tropicbird nest success and population size

Dynamic Power Convertor Development for Radioisotope Power Systems at NASA Glenn Research Center

The Thermal Energy Conversion Branch at NASA Glenn Research Center (GRC) is supporting the development of high-efficiency power convertors for use in Radioisotope Power Systems (RPS). Significant progress was made towards such a system that utilized Stirling conversion during the 2001 to 2015 timeframe. Flight development of the Advanced Stirling Radioisotope Generator (ASRG) was cancelled in 2013 by the Department of Energy (DOE) and NASA Headquarters primarily due to budget constraints, and the Advanced Stirling Convertor (ASC) technology contract was subsequently concluded in 2015. A new chapter of technology development has recently been initiated by the NASA RPS Program. This effort is considering all dynamic power convertor options, such as Stirling and Brayton cycles. Four convertor development contracts supporting this effort were awarded in 2017. The awarded contracts include two free-piston Stirling, one thermoacoustic Stirling, and one turbo-Brayton designs. The technology development contracts each consist of up to three phases: Design, Fabricate, and Test. As of May 2018, all contracts have completed the Design Phase, and each underwent a design review with an independent review board. Three of the contracts are planned to execute the Phase 2 option for fabrication. Convertors manifesting from these development efforts will then undergo independent validation and verification at NASA facilities, which will consist of convertor performance and RPS viability demonstrations. Example tests include launch vibration simulation, performance mapping over the environmental temperature range, and static acceleration exposure. In parallel with this renewed development effort, NASA GRC is still demonstrating free-piston Stirling convertor technology using assets from previous projects. The Stirling Research Laboratory (SRL) is still operating several convertors from previous development projects which have similarities and relevance to current contract designs. Four of which are flexure-bearing based, and another six are gas-bearing based. One of the flexure-bearing convertors has accumulated over 110,000 hours of operation, and holds the current record for maintenance-free heat-engine run-time. Another flexure-bearing convertor was recently manually shutdown after 105,620 hours of operation, then disassembled and inspected. This inspection produced a wealth of information about the effects of this amount of runtime on the technology's components. One of the engineering unit flexure-bearing convertors recently underwent launch simulation vibration test, a static acceleration exposure up to 20 g, and was then placed on extended operation. Amongst the gas-bearing convertors, the longest running unit has accumulated over 70,000 hours of operation. Four high-fidelity gas-bearing convertors from the ASRG project are still operating continuously, for which the longest runtime has reached 28,000 hours

Bioinformatics analysis of circulating miRNAs related to cancer following spinal cord injury

Patients with spinal cord injury (SCI) have an increased risk of developing esophageal, bladder and hematologic malignancies compared with the normal population. In the present study, we aimed to identify, through in silico analysis, miRNAs and their target genes related to the three most frequent types of cancer in individuals with SCI. In a previous study, we reported a pattern of expression of miRNAs in 17 sedentary SCI males compared with 22 healthy able-bodied males by TaqMan OpenArray. This list of miRNAs deregulated in SCI patients was uploaded to miRWALK2.0 to predict the target genes and pathways of selected miRNAs. We used Cytoscape software to construct the network displaying the miRNAs and their gene targets. Among the down-regulated miRNAs in SCI, 21, 19 and 20 miRNAs were potentially associated with hematological, bladder and esophageal cancer, respectively, and three target genes (TP53, CCND1 and KRAS) were common to all three types of cancer. The three up-regulated miRNAs were potentially targeted by 18, 15 and 10 genes associated with all three types of cancer. Our current bioinformatics analysis suggests the potential influence of several miRNAs on the development of cancer in SCI. In general, these data may provide novel information regarding potential molecular mechanisms involved in the development of cancer among individuals with SCI. Further studies aiming at understanding how miRNAs contribute to the development of the major cancers that affect patients after SCI may help elucidate the role of these molecules in the pathophysiology of the disease.39CAPES - Coordenação de Aperfeiçoamento de Pessoal e Nível SuperiorFAPESP – Fundação de Amparo à Pesquisa Do Estado De São PauloSem informação2017/23563-

Nanoscale Processes in the Environment: Nanobiogeochemistry of Microbe/Mineral Interactions

This project involves the application of nanoscience to the fields of fundamental and applied environmental geochemistry and biogeochemistry [1] Probing ligand-mineral interactions at the nanoscale: We have developed a chemical force microscopy (CFM) technique that probes the forces of interaction in aqueous solution between complex organic molecules and mineral surfaces in both distance and force nanospace. Using this method, previously unknown interactions between microbially produced siderophores and iron oxide mineral surfaces have been revealed Iron is a required nutrient for all organisms including bacteria, fungi and plants. The insoluble nature of iron in oxidizing, circumneutral aqueous environments, however, limits concentrations to levels well below the 10 -7 -10 -8 M required for bacterial growth. A response to this limitation is the extracellular release of low molecular weight biomolecules known as siderophores. With formation constants (K f ) on the order of 10 20-10 5 0 , the siderophore-Fe(III) complex is highly stable and thermodynamically favorable under environmental conditions. Indeed, much is known about siderophore interaction with soluble sources of iron; however, the largest source of iron in soils are solid forms, specifically, oxide minerals. Siderophores are known to release ferric iron from minerals, but the nature of the interaction of siderophores with the surface and the associated dissolution mechanism has been unknown. The CFM techniques used in this study have allowed us to directly measure the forces of interaction between siderophores and mineral surfaces for the first time A protein coupling technique was employed to covalently attach the siderophore azotobactin to a hydrazide terminated AFM tip. The activated tip was probed against two minerals: goethite (aFeOOH) and its isostructural Al-equivalent diaspore (a-AlOOH). Upon contact with each mineral surface, the adhesion force between azotobactin and the iron containing goethite was two to three times the value observed for the isostructural Al-equivalent diaspore. The relative force affinity for the iron containing mineral (versus aluminum) correlates with the difference between the aqueous complex formation constants estimated for azotobactin and Fe(III) (aq) (K f =10 2 8 ) and Al(III) (aq) (K f~1 0 1 6 ). Further, the adhesion force between azotobactin and goethite significantly decreases (4 nN to 2 nN) when small amounts of soluble iron (0.1 mM FeCl 3 ·6H 2 O) are added to the system at pH 3.5 suggesting a significant specific interaction between azotobactin's chelating groups and the mineral surface. Specifically, plateau features in the force data generated upon tip retraction fro

Nanoscale Processes in the Environment: Nanobiogeochemistry of Microbe/Mineral Interactions

This project involves the application of nanoscience to the fields of fundamental and applied environmental geochemistry and biogeochemistry [1] Probing ligand-mineral interactions at the nanoscale: We have developed a chemical force microscopy (CFM) technique that probes the forces of interaction in aqueous solution between complex organic molecules and mineral surfaces in both distance and force nanospace. Using this method, previously unknown interactions between microbially produced siderophores and iron oxide mineral surfaces have been revealed Iron is a required nutrient for all organisms including bacteria, fungi and plants. The insoluble nature of iron in oxidizing, circumneutral aqueous environments, however, limits concentrations to levels well below the 10 -7 -10 -8 M required for bacterial growth. A response to this limitation is the extracellular release of low molecular weight biomolecules known as siderophores. With formation constants (K f ) on the order of 10 20-10 5 0 , the siderophore-Fe(III) complex is highly stable and thermodynamically favorable under environmental conditions. Indeed, much is known about siderophore interaction with soluble sources of iron; however, the largest source of iron in soils are solid forms, specifically, oxide minerals. Siderophores are known to release ferric iron from minerals, but the nature of the interaction of siderophores with the surface and the associated dissolution mechanism has been unknown. The CFM techniques used in this study have allowed us to directly measure the forces of interaction between siderophores and mineral surfaces for the first time A protein coupling technique was employed to covalently attach the siderophore azotobactin to a hydrazide terminated AFM tip. The activated tip was probed against two minerals: goethite (aFeOOH) and its isostructural Al-equivalent diaspore (a-AlOOH). Upon contact with each mineral surface, the adhesion force between azotobactin and the iron containing goethite was two to three times the value observed for the isostructural Al-equivalent diaspore. The relative force affinity for the iron containing mineral (versus aluminum) correlates with the difference between the aqueous complex formation constants estimated for azotobactin and Fe(III) (aq) (K f =10 2 8 ) and Al(III) (aq) (K f~1 0 1 6 ). Further, the adhesion force between azotobactin and goethite significantly decreases (4 nN to 2 nN) when small amounts of soluble iron (0.1 mM FeCl 3 ·6H 2 O) are added to the system at pH 3.5 suggesting a significant specific interaction between azotobactin's chelating groups and the mineral surface. Specifically, plateau features in the force data generated upon tip retraction fro