197 research outputs found

    A Stochastic Approach to Designing Affordable, Environmentally Acceptable Systems

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    Presented at the 1999 NSF Grantees Conference, Long Beach, CA, January 1999.The focus of the work being conducted under this grant is to create a virtual stochastic l environment that will enable designers to make decisions in the presence of uncertainty while considering all aspects relevant to the design at the earliest possible time. This paper describes a portion of this research involving the application of a probabilistic method which allows designers to make direct trades between probability of meeting design goals and product performance (such as specific fuel consumption). The example described here is focused on the cycle selection for a notional commercial aircraft engine such that the design merit can be quantified in terms of a probability of meeting a design target. Ultimately, this research will be extended to include environmental aspects such as acoustic noise and emissions requirements

    Minimizing Vehicle Environmental and Economic Cost Via Thermodynamic Work Potential

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    Presented at the 2001 NSF DMII Grantees Conference, Tampa, FL, January 2001.The objective of this paper is to highlight several research opportunities currently being pursued at Georgia Tech to advance the state-of-the-art in vehicle design methods by applying the concept of thermodynamic work potential. The paper begins with a broad definition of thermodynamic work potential and describes several attributes that make it useful for vehicle design. Among these attributes are the ability to link aerothermodynamic performance and vehicle mass together in a "unified theory of vehicle design," as well as the ability to provide a means for explicitly calculating vehicle operating cost accountability. In addition, work potential methods are suggested as an excellent framework from which to conduct technology risk and benefit studies

    Ensuring Continuity of Congress

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    Throughout its history, the U.S. Congress has had several brushes with catastrophe that threatened to prevent it from functioning or to change its balance of power. This report advances reforms to ensure that Congress can continue functioning if many of its members die or become incapacitated or if lawmakers\u27 ability to meet at the Capitol is challenged. It recommends procedures for (1) rapidly replacing members of Congress in the event of mass death or incapacity; (2) declaring members of Congress incapacitated during an emergency; and (3) implementing emergency protocols.https://ir.lawnet.fordham.edu/rule_of_law_clinic/1001/thumbnail.jp

    Some Assembly Required: How Scientific Explanations are Constructed During Clinical Interviews

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    This article is concerned with commonsense science knowledge, the informally-gained knowledge of the natural world that students possess prior to formal instruction in a scientific discipline. Although commonsense science has been the focus of substantial study for more than two decades, there are still profound disagreements about its nature and origin, and its role in science learning. What is the reason that it has been so difficult to reach consensus? We believe that the problems run deep; there are difficulties both with how the field has framed questions and the way that it has gone about seeking answers. In order to make progress, we believe it will be helpful to focus on one type of research instrument – the clinical interview – that is employed in the study of commonsense science. More specifically, we argue that we should seek to understand and model, on a moment-by-moment basis, student reasoning as it occurs in the interviews employed to study commonsense science. To illustrate and support this claim, we draw on a corpus of interviews with middle school students in which the students were asked questions pertaining to the seasons and climate phenomena. Our analysis of this corpus is based on what we call the mode-node framework. In this framework, student reasoning is seen as drawing on a set of knowledge elements we call nodes, and this set produces temporary explanatory structures we call dynamic mental constructs. Furthermore, the analysis of our corpus seeks to highlight certain patterns of student reasoning that occur during interviews, patterns in what we call conceptual dynamics. These include patterns in which students can be seen to search through available knowledge (nodes), in which they assemble nodes into an explanation, and in which they converge on and shift among alternative explanations

    Spitzer Mid-Infrared Observations of Seven Bipolar Planetary Nebulae

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    We have investigated the mid-infrared (MIR) and visual structures of seven bipolar planetary nebulae (BPNe), using imaging and spectroscopy acquired using the Spitzer Space Telescope (SST), and the Observatorio Astronomico Nacional in Mexico. The results show that the sources are more extended towards longer MIR wavelengths, as well as having higher levels of surface brightness in the 5.8 and 8.0 microns bands. It is also noted that the 5.8/4.5 and 8.0/4.5 microns flux ratios increase with increasing distance from the nuclei of the sources. All of these latter trends may be attributable to emission by polycyclic aromatic hydrocarbons (PAHs) and/or warm dust continua within circum-nebular photo-dissociation regions (PDRs). A corresponding decrease in the flux ratios 8.0/5.8 microns may, by contrast, arise due to changes in the properties of the PAH emitting grains. We note evidence for possible 8.0 microns ring-like structures in the envelope of NGC 2346, located in a region beyond the minor axis limits of the ionized envelope. An analysis of the inner two rings shows that whilst they have higher surface brightnesses at longer MIR wavelengths, they are relatively stronger (compared to underlying emission) at 3.6 and 4.5 microns. There is also evidence for point reflection symmetry along the major axis of the outflow.Comment: 27 pages, 22 figures, Accepted for publication in MNRAS. 69 pages in arXi

    Exploring the relationship between chronic undernutrition and asymptomatic malaria in Ghanaian children

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    <p>Abstract</p> <p>Background</p> <p>A moderate association has been found between asymptomatic parasitaemia and undernutrition. However, additional investigation using the gold standard for asymptomatic parasitaemia confirmation, polymerase chain reaction (PCR), is needed to validate this association. Anthropometric measurements and blood samples from children less than five years of age in a rural Ghanaian community were used to determine if an association exists between chronic undernutrition and PCR-confirmed cases of asymptomatic malaria.</p> <p>Methods</p> <p>This was a descriptive cross-sectional study of 214 children less than five years of age from a community near Kumasi, Ghana. Blood samples and anthropometric measurements from these children were collected during physical examinations conducted in January 2007 by partners of the Barekuma Collaborative Community Development Programme.</p> <p>Results</p> <p>Findings from the logistic model predicting the odds of asymptomatic malaria indicate that children who experienced mild, moderate or severe stunting were not more likely to have asymptomatic malaria than children who were not stunted. Children experiencing anaemia had an increased likelihood (OR = 4.15; 95% CI: 1.92, 8.98) of asymptomatic malaria. Similarly, increased spleen size, which was measured by ultrasound, was also associated with asymptomatic malaria (OR = 2.17; 95% CI: 1.44, 3.28). Fast breathing, sex of the child, and age of the child were not significantly associated with the asymptomatic malaria.</p> <p>Conclusions</p> <p>No significant association between chronic undernutrition and presence of asymptomatic malaria was found. Children who experience anaemia and children who have splenomegaly are more likely to present asymptomatic malaria. Programmes aimed at addressing malaria should continue to include nutritional components, especially components that address anaemia.</p

    Missing non-Western voices on social justice for education : a postcolonial perspective on traditions of marginalized communities

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    This chapter reviews the theories and development of a number of non-Western philosophical and legal social justice traditions that have been marginalized in the literature, adopting primarily a postcolonial perspective on how they can contribute to education, transcending colonizer distortions of knowledge to present and draw implications from bodies of knowledge that have been removed from the dominating international literature. This approach is accompanied by a critique of globalization that has, according to many authors, created a hegemonic position for primarily Anglo-American systems in this respect including the view of “epistemicide,” imperialism, “symbolic violence,” and neocolonization, particularly in relation to the right to culture as a social justice principle. Various forms of colonization, including that under the current globalization period, produce cultural hierarchies of values and knowledge, or even expunge cultural and knowledge traditions. This chapter examines selected humanistic traditions of social justice that have existed for centuries, long pre-dating the modern period, focusing on those that have suffered an injustice in their suppression and distortion through a Bourdieuian “symbolic” violence applying not only to the knowledge that is suppressed, expunged, or lost through colonization and globalization and the cultural and intellectual capital they carry but also the identities, values, and traditional social institutions from which they are derived. The first section examines the conceptions and practices of social justice established in ancient Mesopotamia that provides the historical foundation to many later systems. The second presents the Confucian system of social justice as a foundation to the just society that has informed administration, education, and the principles of justice of a number of countries consisting of equitable distribution, equal opportunities, the rights of individuals and the principle of equity. The next section examines the Islamic social justice tradition consisting of distributive, retributive, and fairness and equity and the aim of piety to correct injustices, individually and collectively and establish equal rights for women and men in many spheres and the role of education in emphasizing the role of mind in its critical and reasoning capacities and reason in the formation of character, morality, and the human community with a strong emphasis on education and becoming learned. Finally, a representative selection of indigenous systems of social justice are examined where principles of individual rights and obligations to others and nature carried with them obligations in how others are treated and cared for due to stronger collective rather than individualistic values

    Effectiveness of a national quality improvement programme to improve survival after emergency abdominal surgery (EPOCH): a stepped-wedge cluster-randomised trial

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    Background: Emergency abdominal surgery is associated with poor patient outcomes. We studied the effectiveness of a national quality improvement (QI) programme to implement a care pathway to improve survival for these patients. Methods: We did a stepped-wedge cluster-randomised trial of patients aged 40 years or older undergoing emergency open major abdominal surgery. Eligible UK National Health Service (NHS) hospitals (those that had an emergency general surgical service, a substantial volume of emergency abdominal surgery cases, and contributed data to the National Emergency Laparotomy Audit) were organised into 15 geographical clusters and commenced the QI programme in a random order, based on a computer-generated random sequence, over an 85-week period with one geographical cluster commencing the intervention every 5 weeks from the second to the 16th time period. Patients were masked to the study group, but it was not possible to mask hospital staff or investigators. The primary outcome measure was mortality within 90 days of surgery. Analyses were done on an intention-to-treat basis. This study is registered with the ISRCTN registry, number ISRCTN80682973. Findings: Treatment took place between March 3, 2014, and Oct 19, 2015. 22 754 patients were assessed for elegibility. Of 15 873 eligible patients from 93 NHS hospitals, primary outcome data were analysed for 8482 patients in the usual care group and 7374 in the QI group. Eight patients in the usual care group and nine patients in the QI group were not included in the analysis because of missing primary outcome data. The primary outcome of 90-day mortality occurred in 1210 (16%) patients in the QI group compared with 1393 (16%) patients in the usual care group (HR 1·11, 0·96–1·28). Interpretation: No survival benefit was observed from this QI programme to implement a care pathway for patients undergoing emergency abdominal surgery. Future QI programmes should ensure that teams have both the time and resources needed to improve patient care. Funding: National Institute for Health Research Health Services and Delivery Research Programme
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