86,526 research outputs found

    A Measure of Control for Secondary Cytokine-Induced Injury of Articular Cartilage: A Computational Study

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    In previous works, the author and collaborators establish a mathematical model for injury response in articular cartilage. In this paper we use mathematical software and computational techniques, applied to an existing model to explore in more detail how the behavior of cartilage cells is influenced by several of, what are believed to be, the most significant mechanisms underlying cartilage injury response at the cellular level. We introduce a control parameter, the radius of attenuation, and present some new simulations that shed light on how inflammation associated with cartilage injuries impacts the metabolic activity of cartilage cells. The details presented in the work can help to elucidate targets for more effective therapies in the preventative treatment of post-traumatic osteoarthritis

    Reflections on God and Evil in the Krishna Bhakti Theology of Caitanya

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    The story that forms the short prologue at the start of Valmiki’s Rāmāyana expresses something of how the bhakta deals with tragic loss and senseless violence. In the briefest of words, the story goes something like this: As Valmiki is performing his morning ablutions in the Tamasa River, he witnesses two cranes sweetly cooing at one another lovingly on a branch in a nearby tree. Suddenly, a hunter comes along and shoots an arrow through the chest of the male crane, who immediately drops to the ground. The female, herself alighting on the ground, sees her beloved mate writhing in agony with his mortal wound, and thus she begins to weep, drowning herself in the tears of her sorrow. Valmiki, upon seeing this senseless killing, in his anger curses the hunter from that day on to wander all the days of his life homelessly. Who can mortally wound such an innocent loving creature? What kind of person does this? What kind of senseless act is this? Where is God in all this? Questions such as these are easily elicited from those who hear this story. We shall return to this story following a brief sketch of the relationship between God and evil in a bhakti theology

    Supervision of School-based, Agricultural Education: A Historical Review

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    This study’s purpose was to understand the historical evolution of the supervision of school-based, agricultural education (SBAE). Supervision as a concept is described, including its emergence as an integral part of public school education in the United States. Moreover, the perspectives of early leaders of vocational education, such as Charles Prosser, are examined, as well as the impact of the Smith-Hughes Act of 1917 and other key federal legislation that came afterward. Supervision of SBAE as inspection and administrative oversight and for the purpose of instructional improvement is explored. We also discuss the early supervisory role of teacher educators of agricultural education; the ascendance and, in some cases, later decline of state staff as supervisors; and the role of local school administrators in the supervision of SBAE, including some of the philosophical tensions and divergent views among and between those stakeholders. Implications and recommendations are offered regarding the supervision of SBAE in the future, especially the role of professional organizations, such as the National Association of Agricultural Educators, the American Association for Agricultural Education, and the National Association of Supervisors of Agricultural Education, and their working in concert with The National Council for Agricultural Education

    Modified method of characteristics for the shallow water equations

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    Flow in open channels is frequently modelled using the shallow water equations (SWEs) with an up-winded scheme often used for the nonlinear terms in the numerical scheme (Delis et al., 2000; Erduran et al., 2002). This paper presents a mathematical model based on the SWEs to compute one dimensional (1-D) open channel flow. Two techniques have been used for the simulation of the flood wave along streams which are initially dry. The first one uses up-winding applied to the convective acceleration term in the SWEs to overcome the problem of numerical instabilities. This is applied to the integration of the shallow water equations within the domain, so the scheme does not require any special treatment, such as artificial viscosity or front tracking technique, to capture steep gradients in the solution. As in all initial value problems, the main difficulty is the boundaries, the conventional method of characteristics (MOC) can be applied in a straight forward way for a lot of cases, but when dealing with a very shallow initial depths followed by a flood wave, it is not possible to overcome the problem of reflections. So a modified method of characteristics (MMOC) is the second technique that has been developed by the authors to obtain a fully transparent downstream boundary and is the main subject of this paper. The mathematical model which integrates the SWEs using a staggered finite difference scheme within the domain and the MMOC near the boundary has been tested not only by comparing its results with some analytical solutions for both steady and unsteady flow but also by comparing the results obtained with the results of other models such as Abiola et al. (1988)

    Digital overlaying of the universal transverse Mercator grid with LANDSAT data derived products

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    Picture elements of data from the LANDSAT multispectral scanner are correlated with the universal tranverse Mercator grid. In the procedure, a series of computer modules was used to make approximations of universal transverse Mercator grid locations for all picture elements from the grid locations of a limited number of known control points and to provide display and digital storage of the data. The software has been written in FORTRAN 4 language for a Varian 70-series computer

    Challenges encountered during acid resin transfer preparation of fossil fish from Monte Bolca, Italy

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    Copyright: Palaeontological Association May 2015. This is an open access article, available to all readers online, published under a creative commons licensing (https://creativecommons.org/licenses/by/4.0/). The file attached is the published version of the article

    Subsidies, Market Closure, Cross-Border Investment, and Effects on Competition: The Case of FDI in the Telecommunications Sector

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    Telecommunications long was a sector where sellers of services operated in protected local markets, where law and government regulation created and enforced barriers to entry, especially by foreign firms. In many nations, in fact, the provision of telecommunications services was reserved for state-owned monopoly suppliers. During the late 1980s and through the 1990s, however, many of these barriers have been removed while formerly state-owned firms have been partially or wholly privatized. This has in turn engendered some cross entry by telecom service providers; firms that once were purely domestic in the scope of their operations thus have become multinational. During the summer of 2000, however, US Senator Ernest Hollings, with co-sponsorship of 29 other US Senators, introduced a bill (S.2793) in the US Congress that would have effectively blocked non-US telecommunications service providers from acquiring US telecom firms if the former were state-owned, or even only partly state-owned. The bill was aimed specifically at the proposed acquisition of US mobile telecommunications service provider Voice Stream by the German firm Deutsche Telekom (DT), but the language of the bill would have served to block virtually any non-US state-owned firm in the telecom sector from buying a US firm. While the bill did not become law, it reflected a long history of efforts in Congress to prevent US firms from being acquired by state-owned non-US firms (e.g., a legislative bill to do this had been introduced by Senator Frank Murkowski during the late 1980s, and while this bill also failed to be passed into law, some provisions from the bill were incorporated into the Exon-Florio legislation that was first enacted as a temporary measure in 1988 but subsequently made part of US permanent law in 1992). The Hollings bill was doubtlessly motivated in part by xenophobia (Senator Hollings is himself of the American generation that fought Germany during World War II). But it was also motivated, as was the Murkowski bill a decade earlier, by fears that subsidies and/or monopoly profits accruing to state-owned firms in their home markets might be used to affect operations in the US market to the detriment of locally-owned competitors. The extreme case of such behavior would be predatory pricing by the state-owned firm aimed at bankrupting its competitors, where temporary losses created by below-cost pricing in the US market would be offset by subsidies or monopoly profits in the home market. The ultimate goal of the predatory firm would be to establish a monopoly in the United States. In fact, the Hollings bill was shelved in part because DT was able to establish that it was neither a recipient of significant subsidies in Germany nor a monopoly service provider in the German market (although the firm once held a statutory monopoly there, the market has been opened to competition and some new entry has occurred). Also figuring in the shelving of the bill was argumentation that competition in the US market for wireless telecom services would be enhanced by the entry of DT. However, fears have persisted about the possibly deleterious effects of subsidies or monopoly profits garnered by a firm in its home market on competition in a geographically separate market in which that firm (or a subsidiary of that firm) is a seller. Indeed, the issues raised by the Hollings bill pertain to numerous sectors in which multinational firms compete. Accordingly, the US Council of Economic Advisors was ordered by the US President following the introduction of the Hollings bill to advise on what might be the effects of such competition.

    Economic Issues Raised by Treatment of Takings Under NAFTA Chapter 11

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    Chapter 11 of the North American Free Trade Agreement (NAFTA) allows most foreign investors from any NAFTA country to seek monetary damages for properties that might be appropriated, or any measure that might be deemed "tantamount to an expropriation" by the governments of any of the other NAFTA parties (Canada, Mexico, and the United States); to obtain such damages, the investor must go through the dispute settlement process provided in chapter 11 part B. A number of investors have used these provisions to argue that diminished value of an investment due to environment regulation is indeed tantamount to an expropriation and hence subject to monetary damages. If this line of argumentation is generally upheld, it would amount to a requirement that governments compensate investors for losses resulting from requirements to implement environmental safeguards (or to cease from activities that cause environmental damage). This article uses the reasoning of Ronald Coase, which is extensively articulated for the benefit of readers not familiar with this reasoning, to argue that in fact that such a requirement can in fact lead to an optimal outcome in terms of tradeoff of cost/benefit of an environmental regulation. However, Coase argued also that a requirement that the "polluter pay" can also lead to an optimal outcome, and for reasons of perceived equity, this latter approach is most often implemented in environmental regulation. The article goes further to argue that for a number of reasons not considered by Coase, the latter approach might, in an imperfect world where conditions for optimality are violated, in fact come closer to achieving an optimal outcome than the former.

    Serological survey of anti-group A rotavirus IgM in UK adults

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    Rotaviral associated disease of infants in the UK is seasonal and infection in adults not uncommon but the relationship between these has been little explored. Adult sera collected monthly for one year from routine hospital samples were screened for the presence of anti-group A rotavirus immunoglobulin M class antibodies as a marker of recent infection. Anti-rotavirus IgM was seen in all age groups throughout the year with little obvious seasonal variation in the distribution of antibody levels. IgM concentrations and the proportion seropositive above a threshold both increased with age with high concentrations consistently observed in the elderly. Results suggest either high infection rates of rotavirus in adults, irrespective of seasonal disease incidence in infants, IgM persistence or IgM cross-reactivity. These results support recent evidence of differences between infant and adult rotavirus epidemiology and highlight the need for more extensive surveys to investigate age and time related infection and transmission of rotavirus
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