50 research outputs found

    Fault diagnostic instrumentation design for environmental control and life support systems

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    As a development phase moves toward flight hardware, the system availability becomes an important design aspect which requires high reliability and maintainability. As part of continous development efforts, a program to evaluate, design, and demonstrate advanced instrumentation fault diagnostics was successfully completed. Fault tolerance designs for reliability and other instrumenation capabilities to increase maintainability were evaluated and studied

    Identical Particle Scattering From A Weakly Coupled Bose-Einstein Condensed Gas

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    We calculate the scattering states and cross sections for a Bose-Einstein condensed dilute gas trapped in a spherical square well of finite depth. The interactions are treated in the scattering length approximation. We solve the Gross-Pitaevskii equation and the Bogoliubov equations for bound and scattering states. The results show that there are transparency effects reminiscent of those conjectured to occur for strongly coupled systems. When incident particle wavelengths λ are comparable to the well size a, exchange induced transparency enhancement is dramatic only for particular combinations of well depth, interaction strength, and particle number. For particles with large momenta (a/λ≫1),however, exchange with the condensate results in enhanced transmission for all coupling strengths. We calculated the rate of decay of the scattering states to leading order in anharmonic corrections to the Bogoliubov approximation and found the corresponding inelastic cross sections to be extremely small

    The Ability of Cardiac Autonomic Modulations Stress Index to Independently Predict VO2max in Cardiometabolically Healthy Individuals

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    Cardiac autonomic modulation (CAM) is crucial for heart health, mediated by the sympathetic and autonomic systems (SAS). The link between CAM and aerobic exercise underscores the importance of aerobic fitness assessments in optimizing training to enhance performance. Heart rate variability (HRV) assesses CAM in various healthy populations, with the Stress Index (SI) identified as key in determining the SAS regulation involvement in performance and recovery outcomes. The SI may provide a quick and non-invasive metric to assess aerobic performance. PURPOSE: To determine if the SI can accurately predict aerobic performance via VO2max in healthy individuals free of metabolic diseases. METHODS: fifty cardiometabolically healthy individuals (n = 30 males, n = 20 females; Age 37.8 + 12.7 years, %BF 24.9 + 4.0) completed a single maximal treadmill exercise protocol to determine VO2max. HRV was measured for 5 minutes in the supine position prior to performing the exercise protocol using an elastic belt and Bluetooth monitor (Polar H7). CardioMood software was used to process HRV indices; SI, high frequency (HF), low frequency (LF), and total power (TP) were assessed for the frequency domain, and standard deviation of all NN intervals (SDNN) and the square root of the mean of the squares of successive R-R interval differences (RMSSD) for the time domain. The data was analyzed using a multiple correlation and linear regression between HRV indices and VO2max to determine the relationship between the two. All analyses were performed using SAS (v. 28.0.1.1). RESULTS: HRV indices SI was not significantly correlated to VO2max (r = -0.118, p = 0.414). Additionally, SI and all other HRV indices were not able to independently or combined predict VO2max (R2 = 0.014, p = 0.414). CONCLUSION: The utilization of HRV to assess CAM has proven beneficial in multiple clinical and athletic settings. However, the utilization of the SI to predict aerobic performance via VO2max does not appear to be significant. Thus, there are potential limitations to HRV to non-invasively assess aerobic performance

    Identical particle scattering from a weakly coupled Bose-Einstein condensed gas

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    We calculate the scattering states and cross sections for a Bose-Einstein condensed dilute gas trapped in a spherical square well of finite depth. The interactions are treated in the scattering length approximation. We solve the Gross-Pitaevskii equation and the Bogoliubov equations for bound and scattering states. The results show that there are transparency effects reminiscent of those conjectured to occur for strongly coupled systems. When incident particle wavelengths λ are comparable to the well size a, exchange induced transparency enhancement is dramatic only for particular combinations of well depth, interaction strength, and particle number. For particles with large momenta (a/λ≫1),however, exchange with the condensate results in enhanced transmission for all coupling strengths. We calculated the rate of decay of the scattering states to leading order in anharmonic corrections to the Bogoliubov approximation and found the corresponding inelastic cross sections to be extremely small

    Climate change, the Great Barrier Reef and the response of Australians

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    © 2016, Palgrave Macmillan Ltd. All rights reserved. Inspiration, aspirations, attitudes, and perception of threats play a pivotal role in the way that individuals associate themselves with natural environments. These sentiments affect how people connect to natural places, including their behaviours, perceived responsibility, and the management interventions they support. World Heritage Areas hold an important place in the lives of people who visit, aspire to visit, or derive a sense of security and well-being from their existence. Yet, the connection between people and special places is rarely quantified and policymakers find it difficult to incorporate these human dimensions into decision-making processes. Here we describe the personal concern and connection that Australians have with the Great Barrier Reef and discuss how the results may help with its management. We utilize a statistically representative sample of Australian residents (n = 2,002) and show empirically that climate change is perceived to be the biggest threat to the Great Barrier Reef, and that the Great Barrier Reef inspires Australians, promotes pride, and instills a sense of individual identity and collective responsibility to protect it. An increased understanding of the high levels of personal connection to iconic natural resources may help managers to enhance public support for protecting climate-sensitive systems within Australia and around the world

    Cystic mucinous adenocarcinoma of the lung: a case report

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    Mucinous cystic tumors of the lung are uncommon, the preoperative pathologic diagnosis is difficult and their biological behavior is still controversial. We report the case of a patient with a clinically benign cystic lesion that post-operatively showed to be consistent with an invasive adenocarcinoma arising in a mucinous cystadenoma of the lung

    Stakeholder perspectives on shale gas fracking: A Q-method study of environmental discourses

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    The rapid expansion of shale gas exploration worldwide is a significant source of environmental controversy. Successful shale gas policymaking is dependent upon a clear understanding of the dynamics of competing stakeholder perspectives on these issues, and so methods are needed to delineate the areas of agreement and conflict that emerge. This empirical study, based in the United Kingdom, examines emergent perspectives on a range of environmental, health and socio-economic impacts associated with shale gas fracking using Q- methodology: a combined qualitative-quantitative approach. The analysis reveals three typologies of perspectives amongst key industry, civil society and non-affiliated citizen stakeholders; subsequently contextualised in relation to Dryzek’s typology of environmental discourses. These are labelled A) “Don’t trust the fossil fuels industry: campaign for renewables” (mediating between sustainable development and democratic pragmatism discourses); B) “Shale gas is a bridge fuel: economic growth and environmental scepticism” (mediating between economic rationalism and ecological modernisation discourses); and C) “Take place protective action and legislate in the public interest” (reflecting a discourse of administrative rationalism). The implications of these competing discourses for nascent shale gas policy in the UK are discussed in light of recent Government public consultation on changes to national planning policy

    Mucinous cystic neoplasms of the mesentery: a case report and review of the literature

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    <p>Abstract</p> <p>Background</p> <p>Mucinous cystic neoplasms arise in the ovary and various extra-ovarian sites. While their pathogenesis remains conjectural, their similarities suggest a common pathway of development. There have been rare reports involving the mesentery as a primary tumour site.</p> <p>Case presentation</p> <p>A cystic mass of uncertain origin was demonstrated radiologically in a 22 year old female with chronic abdominal pain. At laparotomy, the mass was fixed within the colonic mesentery. Histology demonstrated a benign mucinous cystadenoma.</p> <p>Methods and results</p> <p>We review the literature on mucinous cystic neoplasms of the mesentery and report on the pathogenesis, biologic behavior, diagnosis and treatment of similar extra-ovarian tumors. We propose an updated classification of mesenteric cysts and cystic tumors.</p> <p>Conclusion</p> <p>Mucinous cystic neoplasms of the mesentery present almost exclusively in women and must be considered in the differential diagnosis of mesenteric tumors. Only full histological examination of a mucinous cystic neoplasm can exclude a borderline or malignant component. An updated classification of mesenteric cysts and cystic tumors is proposed.</p
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