970 resultados para Critical problems


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In this paper I review the ways in which the glassy state is obtained both in nature and in materials science and highlight a "new twist"--the recent recognition of polymorphism within the glassy state. The formation of glass by continuous cooling (viscous slowdown) is then examined, the strong/fragile liquids classification is reviewed, and a new twist-the possibility that the slowdown is a result of an avoided critical point-is noted. The three canonical characteristics of relaxing liquids are correlated through the fragility. As a further new twist, the conversion of strong liquids to fragile liquids by pressure-induced coordination number increases is demonstrated. It is then shown that, for comparable systems, it is possible to have the same conversion accomplished via a first-order transition within the liquid state during quenching. This occurs in the systems in which "polyamorphism" (polymorphism in the glassy state) is observed, and the whole phenomenology is accounted for by Poole's bond-modified van der Waals model. The sudden loss of some liquid degrees of freedom through such weak first-order transitions is then related to the polyamorphic transition between native and denatured hydrated proteins, since the latter are also glass-forming systems--water-plasticized, hydrogen bond-cross-linked chain polymers (and single molecule glass formers). The circle is closed with a final new twist by noting that a short time scale phenomenon much studied by protein physicists-namely, the onset of a sharp change in d/dT ( is the Debye-Waller factor)--is general for glass-forming liquids, including computer-simulated strong and fragile ionic liquids, and is closely correlated with the experimental glass transition temperature. The latter thus originates in strong anharmonicity in certain components of the vibrational density of states, which permits the system to access the multiple minima of its configuration space. The connection between the anharmonicity in these modes, vibrational localization, the Kauzmann temperature, and the fragility of the liquid is proposed as the key problem in glass science.

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We study the critical behavior of the diluted antiferromagnet in a field with the tethered Monte Carlo formalism. We compute the critical exponents (including the elusive hyperscaling violations exponent θ). Our results provide a comprehensive description of the phase transition and clarify the inconsistencies between previous experimental and theoretical work. To do so, our method addresses the usual problems of numerical work (large tunneling barriers and self-averaging violations).

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Investigation about the psychological experiences of the reproductive life cycle showed that in critical moments special reactions may happen. These reactions seem to be defensive in nature, are set in motion in order to promote some kind of emotional protection and are performed in two opposite directions: a) a decreasing of the contact with aggressive impulses and b) an increasing of the use of rationalization and denial of frustrating situations. Examples of those rearrangements were observed at samples of: 1) pregnant women in obstetric high-risk consultation, 2) infertile couples waiting for infertility consultations and 3) pregnant women waiting for amniocentesis results. These data seem to be in accordance with the classical psychological points of view: a) gestation should be considered as a period of protection, b) during pregnancy a “primary maternal preoccupation” (Winnicot, 1958) emerges leading to the mobilization of all resources available for pregnant women and c) along gestational development psychological changes show how flexible maternal functioning may become. What was not expected is that in the absence of pregnancy, infertile couples should behave very similarly to what it is observed when pregnancy is in danger or when medical problems about the mother’s or the baby’s health arise in the horizon. Due to its “freezing” consequences upon emotional development we propose that this kind of reaction will be designated as “stand-by reaction”.

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This paper departs from this point to consider whether and how crisis thinking contributes to practices of affirmative critique and transformative social action in late-capitalist societies. I argue that different deployments of crisis thinking have different ‘affect-effects’ and consequences for ethical and political practice. Some work to mobilize political action through articulating a politics of fear, assuming that people take most responsibility for the future when they fear the alternatives. Other forms of crisis thinking work to heighten critical awareness by disrupting existential certainty, asserting an ‘ethics of ambiguity’ which assumes that the continuous production of uncertain futures is a fundamental part of the human condition (de Beauvoir, 2000). In this paper, I hope to illustrate that the first deployment of crisis thinking can easily justify the closing down of political debate, discouraging radical experimentation and critique for the sake of resolving problems in a timely and decisive way. The second approach to crisis thinking, on the other hand, has greater potential to enable intellectual and political alterity in everyday life—but one that poses considerable challenges for our understandings of and responses to climate change...

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The present dissertation is concerned with the determination of the magnetic field distribution in ma[.rnetic electron lenses by means of the finite element method. In the differential form of this method a Poisson type equation is solved by numerical methods over a finite boundary. Previous methods of adapting this procedure to the requirements of digital computers have restricted its use to computers of extremely large core size. It is shown that by reformulating the boundary conditions, a considerable reduction in core store can be achieved for a given accuracy of field distribution. The magnetic field distribution of a lens may also be calculated by the integral form of the finite element rnethod. This eliminates boundary problems mentioned but introduces other difficulties. After a careful analysis of both methods it has proved possible to combine the advantages of both in a .new approach to the problem which may be called the 'differential-integral' finite element method. The application of this method to the determination of the magnetic field distribution of some new types of magnetic lenses is described. In the course of the work considerable re-programming of standard programs was necessary in order to reduce the core store requirements to a minimum.

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In the contemporary customer-driven supply chain, maximization of customer service plays an equally important role as minimization of costs for a company to retain and increase its competitiveness. This article develops a multiple-criteria optimization approach, combining the analytic hierarchy process (AHP) and an integer linear programming (ILP) model, to aid the design of an optimal logistics distribution network. The proposed approach outperforms traditional cost-based optimization techniques because it considers both quantitative and qualitative factors and also aims at maximizing the benefits of deliverer and customers. In the approach, the AHP is used to determine the relative importance weightings or priorities of alternative warehouses with respect to some critical customer-oriented criteria. The results of AHP prioritization are utilized as the input of the ILP model, the objective of which is to select the best warehouses at the lowest possible cost. In this article, two commercial packages are used: including Expert Choice and LINDO.

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The aim of this study is to address the main deficiencies with the prevailing project cost and time control practices for construction projects in the UK. A questionnaire survey was carried out with 250 top companies followed by in-depth interviews with 15 experienced practitioners from these companies in order to gain further insights of the identified problems, and their experience of good practice on how these problems can be tackled. On the basis of these interviews and syntheses with literature, a list of 65 good practice recommendations have been developed for the key project control tasks: planning, monitoring, reporting and analysing. The Delphi method was then used, with the participation of a panel of 8 practitioner experts, to evaluate these improvement recommendations and to establish their degree of relevance. After two rounds of Delphi, these recommendations are put forward as "critical", "important", or "helpful" measures for improving project control practice.

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We prove some multiplicity results concerning quasilinear elliptic equations with natural growth conditions. Techniques of nonsmooth critical point theory are employed.

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* Supported by Ministero dell’Università e della Ricerca Scientifica e Tecnologica (40% – 1993). ** Supported by Ministero dell’Università e della Ricerca Scientifica e Tecnologica (40% – 1993).

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One of the major problems for Critical Discourse Analysts is how to move on from their insightful critical analyses to successfully 'acting on the world in order to transform it'. This paper discusses, with detailed exemplification, some of the areas where linguists have moved beyond description to acting on and changing the world. Examples from three murder trials show how essential it is, in order to protect the rights of witnesses and defendants, to have audio records of significant interviews with police officers. The article moves on to discuss the potentially serious consequences of the many communicative problems inherent in legal/lay interaction and illustrates a few of the linguist-led improvements to important texts. Finally, the article turns to the problems of using linguistic data to try to determine the geographical origin of asylum seekers. The intention of the article is to act as a call to arms to linguists; it concludes with the observation that 'innumerable mountains remain for those with a critical linguistic perspective who would like to try to move one'. © 2011 John Benjamins Publishing Company.

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A nemzetközi, elsősorban európai szervezettudományban mára meghatározóvá vált a kritikai megközelítés, a hazai szakirodalomban mégis elvétve találni rá utalásokat. A szerzők írásukban tárgyalják, hogy a kritikai menedzsmentelméletek (KME) szemszögéből miként bírálható a mindenkori szervezeti gyakorlat, és miért bírálandók a főáramú menedzsmentelméletek. A tanulmány fő részében elméleti megkülönböztetéseket tesznek: egyrészt elhatárolják a kritikai megközelítést a főáramú szervezetelméletektől, másrészt több szempontból is különbséget tesznek a különféle – de egyaránt a KME alá tartozó – kritikai megközelítések között. De a kritikai szemlélethez hűen nem csak a puszta elméletismertetés volt a céljuk: e bevezetés és problémafelvető tanulmány – s a későbbiekben tervezett cikksorozat – szándékuk szerint vitaindítóként is szolgál. Abban bíznak, hogy a felvetett kérdésekről valódi, lényegi párbeszédet generálhatnak a hazai menedzsmenttudományban (kutatók, oktatók és elméletalkalmazók körében), mely kihathat a szervezeti gyakorlatra is. _____ Critical Management Studies (CMS) as a field of organization studies (OS) has become central internationally, and especially in Europe. Yet, its appearance is still very rare in the Hungarian OS literature. In this study first the authors discuss how the nowadays dominant organizational practices along with the mainstream management and organization theories are to be criticized from a Critical Management perspective. In the main section, so as to define CMS, they make important theoretical distinctions, first between CMS and mainstream organization theories (in general), and then among the different critical approaches that nevertheless all fall under the broad CMS umbrella. But, in line with a truly critical attitude, they not only go into theoretical discussions but, at least to their intention, the purpose of this introductory paper is also to addresses important problems both in the theory and the practice of organization and management. Therefore, it could serve as an opening of an important debate or dialogue in the Hungarian academic community (researchers, educators and other professionals), a theoretical discussion that could have real influence on organizational practice too.

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The job of a principal is becoming more demanding and more critical each year. Principals are asked to undertake huge challenges and to succeed regardless of what obstacles lie ahead. The purpose of this study was to identify which Administrative Task Areas and Specific Task Areas caused the most difficulties for first- and second-year principals.^ A survey was taken of first- and second-year principals in Dade County, Florida. These beginning principals rated their level of proficiency for each administrative task area and each specific task within those areas. Participants rated their perceptions on a scale from one to four. The data were analyzed based on frequency distributions, percentages, means, and standard deviations.^ Beginning principals perceived themselves as least proficient in the administrative task areas of management and personnel duties. They believed their strongest areas were curriculum and instruction and school-community relations. Within these areas, the specific administrative task areas identified as most problematic were identifying proper procedures for construction in the schools, visiting classrooms to help teachers improve instruction, awareness of issues related to school law, establishing accounting procedures for the school's internal funds, and procedures for dismissing incompetent staff members.^ Many beginning principals surveyed volunteered to make recommendations for future beginning principals. Of these recommendations, the most popular responses addressed obtaining more experience with the budget and internal funds prior to becoming a principal. In addition, there was a strong need for more training dealing with school personnel and the importance of networking with a veteran principal.^ The principal training programs for five of the largest school districts in Florida were reviewed. These programs were found to incorporate a vast amount of the recommendations included in the literature. Florida is moving in the right direction toward excellence in the public schools. ^

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Transparency is an important concept in International Relations. The possibility of realizing transparency in practice operates as a central analytical axis defining distinct positions on core theoretical problems within the field, from the security dilemma to the function of international institutions and beyond. As a political practice the pursuit of transparent governance is a dominant feature of global politics, promoted by a wide range of actors across a vast range of issue areas, from nuclear proliferation to Internet governance to the politics of foreign aid. Yet, despite its importance, precisely what transparency means or how the concept is understood is frequently ill-defined by academics and policy-makers alike. As a result, the epistemological and ontological underpinnings of approaches to transparency in IR often sit in tension with their wider theoretical commitments. This article will examine the three primary understandings of transparency used in IR in order to unpack these commitments. It finds that while transparency is often explicitly conceptualized as a property of information, particularly within rationalist scholarship, this understanding rests upon an unarticulated set of sociological assumptions. This analysis suggests that conceptualizing ‘transparency-as-information’ without a wider sociology of knowledge production is highly problematic, potentially obscuring our ability to recognize transparent practices in global governance. Understanding transparency as dialogue, as a social practice rooted in shared cognitive capacities and epistemic frameworks, provides a firmer analytical ground from which to examine transparency in International Relations.

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This article examines how we can encourage students to engage critically with marketing ideas and activities. Critical marketing studies are currently on the margins of the discipline, and the ideas and challenges to conventional marketing studies posed by critical scholars are rarely tested or implemented in the marketing classroom. Often these are perceived as too academic and elitist to be relevant to the modern business environment. Drawing largely from debates in the management education literature, this article discusses the problems and possibilities of introducing critical reflection into the marketing curriculum and describes some strategies for encouraging critique in the marketing classroom.