6,021 research outputs found

    THE EFFECT OF UNREPORTED DEMAND ON THE ​F/A-18’S SUPPLY CHAIN

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    This research investigates the causes of unreported demand associated with F/A-18 aircraft components during the execution of cannibalization and the issuance of repairable parts from the Stricken Aircraft Reclamation and Disposal Program (SARDIP). The current transition to the F-35 Joint Strike Fighter across the entire Marine Corps F/A-18 Type Model Series (TMS) platform provides an opportunity to research and analyze various aspects of the divestiture process. During the divestiture period of the F/A-18 platform, missing demand signals lead to inaccuracies in demand forecasting. This inaccurate demand capture increases stress on the supply system and future funding requirements within the organization. This study analyzes five years of demand data gathered from the Navy Enterprise Resource Planning (ERP) system in order to identify causes and sources of lost demand associated with cannibalization and SARDIP issues. In addition, this study presents an analysis of current Marine Corps aviation supply policies and cannibalization actions to identify shortfalls in demand reporting. The data gathered suggest that unreported demand leads to increases in demand variability and the ability to allocate funds for F/A-18 components. Although the impacts of unreported demand for the F/A-18 will disappear once the platform is no longer in service, unreported demand will continue to affect all aircraft remaining in service.Captain, United States Marine CorpsCaptain, United States Marine CorpsMajor, United States Marine CorpsApproved for public release. Distribution is unlimited

    The dissipative effect of thermal radiation loss in high-temperature dense plasmas

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    A dynamical model based on the two-fluid dynamical equations with energy generation and loss is obtained and used to investigate the self-generated magnetic fields in high-temperature dense plasmas such as the solar core. The self-generation of magnetic fields might be looked at as a self-organization-type behavior of stochastic thermal radiation fields, as expected for an open dissipative system according to Prigogine's theory of dissipative structures.Comment: 4 pages, 1 postscript figure included; RevTeX3.0, epsf.tex neede

    Genetic Engineering of Lesquerella with Increased Ricinoleic Acid Content in Seed Oil

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    Seeds of castor (Ricinus communis) are enriched in oil with high levels of the industrially valuable fatty acid ricinoleic acid (18:1OH), but production of this plant is limited because of the cooccurrence of the ricin toxin in its seeds. Lesquerella (Physaria fendleri) is being developed as an alternative industrial oilseed because its seeds accumulate lesquerolic acid (20:1OH), an elongated form of 18:1OH in seed oil which lacks toxins. Synthesis of 20:1OH is through elongation of 18:1OH by a lesquerella elongase, PfKCS18. Oleic acid (18:1) is the substrate for 18:1OH synthesis, but it is also used by fatty acid desaturase 2 (FAD2) and FAD3 to sequentially produce linoleic and linolenic acids. To develop lesquerella that produces 18:1OH-rich seed oils such as castor, RNA interference sequences targeting KCS18, FAD2 and FAD3 were introduced to lesquerella to suppress the elongation and desaturation steps. Seeds from transgenic lines had increased 18:1OH to 1.1–26.6% compared with that of 0.4–0.6% in wild-type (WT) seeds. Multiple lines had reduced 18:1OH levels in the T2 generation, including a top line with 18:1OH reduced from 26.7% to 19%. Transgenic lines also accumulated more 18:1 than that of WT, indicating that 18:1 is not efficiently used for 18:1OH synthesis and accumulation. Factors limiting 18:1OH accumulation and new targets for further increasing 18:1OH production are discussed. Our results provide insights into complex mechanisms of oil biosynthesis in lesquerella and show the biotechnological potential to tailor lesquerella seeds to produce castor-like industrial oil functionality

    The Berry phase in inflationary cosmology

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    We derive an analogue of the Berry phase associated with inflationary cosmological perturbations of quantum mechanical origin by obtaining the corresponding wavefunction. We have further shown that cosmological Berry phase can be completely envisioned through the observable parameters, viz. spectral indices. Finally, physical significance of this phase is discussed from the point of view of theoretical and observational aspects with some possible consequences of this quantity in inflationary cosmology.Comment: 9 pages, Modified version to appear in Classical and Quantum Gravity. arXiv admin note: text overlap with arXiv:quant-ph/0307084 by other author

    Hablamos Juntos (Together We Speak): Interpreters, Provider Communication, and Satisfaction with Care

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    The Hablamos Juntos—Together We Speak (HJ)—national demonstration project targeted the improvement of language access for Spanish-speaking Latinos in areas with rapidly growing Latino populations. The objective of HJ was to improve doctor-patient communication by increasing access to and quality of interpreter services for Spanish-speaking patients. To investigate how access to interpreters for adult Spanish-speaking Latinos is associated with ratings of doctor/office staff communication and satisfaction with care. Cross-sectional cohort study. A total of 1,590 Spanish-speaking Latino adults from eight sites across the United States who participated in the outpatient HJ evaluation. We analyzed two multi-item measures of doctor communication (4 items) and office staff helpfulness (2 items), and one global item of satisfaction with care by interpreter use. We performed regression analyses to control for patient sociodemographic characteristics, survey year, and clustering at the site of care. Ninety-five percent of participants were born outside the US, 81% were females, and survey response rates ranged from 45% to 85% across sites. In this cohort of Spanish-speaking patients, those who needed and always used interpreters reported better experiences with care than their counterparts who needed but had interpreters unavailable. Patients who always used an interpreter had better adjusted ratings of doctor communication [effect size (ES = 0.51)], office staff helpfulness (ES = 0.37), and satisfaction with care (ES = 0.37) than patients who needed but did not always use an interpreter. Patients who needed and always used interpreters also reported better experiences with care in all three domains measured [doctor communication (ES = 0.30), office staff helpfulness (ES = 0.21), and satisfaction with care (ES = 0.23)] than patients who did not need interpreters. Among adult Spanish-speaking Latinos, interpreter use is independently associated with higher satisfaction with doctor communication, office staff helpfulness, and ambulatory care. Increased attention to the need for effective interpreter services is warranted in areas with rapidly growing Spanish-speaking populations

    Economic transition and speculative urbanisation in China: gentrification versus dispossession

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    Gentrification requires properties to be available for investment through market transactions. In mainland China which has gone through transition from a planned to a market economy, it is necessary to unleash decommodified real estate properties and make them amenable to investment. This entails inhabitants’ dispossession to dissociate them from claiming their rights to the properties and to their neighbourhoods. This paper argues that while China’s urban accumulation may have produced new-build gentrification, redevelopment projects have been targeting dilapidated urban spaces that are yet to be fully converted into commodities. This means that dispossession is a precursor to gentrification. Dispossession occurs through both coercion and co-optation, and reflects the pathdependency of China’s socialist legacy. The findings contribute to the debates on contextualising the workings of gentrification in the global South, and highlight the importance of identifying multiple urban processes at work to produce gentrification and speculative urban accumulation

    Obstáculos epistemológicos en la comprensión del concepto: respiración celular en estudiantes de dos niveles educativos diferentes

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    The objective of this article is to recognize the epistemological obstacles present in the conception of Cellular Respiration in two student populations, the first of grade eleven of the urban college in Duitama Boyacá and the second of eighth semester of the undergraduate degree in Biology of the University District Francisco José de Caldas in the city of Bogotá. For this, two qualitative surveys were used, using Bloom's taxonomy for the drafting of the same, with open-ended questions to avoid a capricious response (Cubero, 1997) and one of them with a drawing option in which the data obtained were tabulated and subsequently analyzed in accordance with Bachelard (1975). The most prevalent obstacles in young people are the basic experience, general knowledge and verbal obstacle, which prevent a theoretical rupture of knowledge, avoiding an epistemic formation of knowledge and that in turn, feeding our submissive mind. (Pozo, 1989).El presente artículo tiene como objetivo reconocer los obstáculos epistemológicos presentes en la concepción de Respiración Celular en dos poblaciones de estudiantes, la primera de grado once del Colegio Urbano en Duitama Boyacá y la segunda de octavo semestre del pregrado en Licenciatura en Biología de la Universidad Distrital Francisco José de Caldas en la ciudad de Bogotá. Para ello, se hizo uso de dos encuestas de carácter cualitativo, empleando la taxonomía de Bloom para la redacción de la misma, con preguntas de tipo abierta para evitar una respuesta de forma caprichosa (Cubero,1997) y una de ellas con opción de dibujo en donde los datos obtenidos fueron tabulados y posteriormente analizados de acuerdo con Bachelard (1938). Los obstáculos con mayor prevalencia en los jóvenes son la experiencia básica, conocimiento general y obstáculo verbal, los cuales impiden una ruptura teórica del saber, evitando una formación epistémica del conocimiento y que, a su vez, la alimentación de una mente sumisa (Pozo, 1989)

    Self-Transforming Configuration Based on Atmospheric-Adaptive Materials for Solid Oxide Cells

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    Solid oxide cells (SOC) with a symmetrical configuration have been focused due to the practical benefits of such configurations, such as minimized compatibility issues, a simple fabrication process and reduced cost compared to SOCs with the asymmetrical configuration. However, the performance of SOCs using a single type of electrode material (symmetrical configuration) is lower than the performance of those using the dissimilar electrode materials (asymmetrical configuration). Therefore, to achieve a high-performance cell, we design a 'self-transforming cell' with the asymmetric configuration using only materials of the single type, one based on atmospheric adaptive materials. Atmospheric-adaptive perovskite Pr0.5Ba0.5Mn0.85Co0.15O3-delta (PBMCo) was used for the so-called self-transforming cell electrodes, which changed to layered perovskite and metal in the fuel atmosphere and retained its original structure in the air atmosphere. In fuel cell mods, the self-transforming cell shows excellent electrochemical performance of 1.10Wcm(-2) at 800 degrees C and good stability for 100 h without any catalyst. In electrolysis mode, the moderate current densities of -0.42A cm(-2) for 3 vol.% H2O and -0.62 A cm(-2) for 10 vol.% H2O, respectively, were observed at a cell voltage of 1.3V at 800 degrees C. In the reversible cycling test, the transforming cell maintains the constant voltages for 30 h at +/- 0.2A cm(-2) under 10 vol. % H2O

    Isocurvature perturbations in extra radiation

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    Recent cosmological observations, including measurements of the CMB anisotropy and the primordial helium abundance, indicate the existence of an extra radiation component in the Universe beyond the standard three neutrino species. In this paper we explore the possibility that the extra radiation has isocurvatrue fluctuations. A general formalism to evaluate isocurvature perturbations in the extra radiation is provided in the mixed inflaton-curvaton system, where the extra radiation is produced by the decay of both scalar fields. We also derive constraints on the abundance of the extra radiation and the amount of its isocurvature perturbation. Current observational data favors the existence of an extra radiation component, but does not indicate its having isocurvature perturbation. These constraints are applied to some particle physics motivated models. If future observations detect isocurvature perturbations in the extra radiation, it will give us a hint to the origin of the extra radiation.Comment: 41 pages, 8 figures; version accepted for publication in JCA
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