973 resultados para Mixed state-control constraints


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Controlled choice over public schools attempts giving options to parents while maintaining diversity, often enforced by setting feasibility constraints with hard upper and lower bounds for each student type. We demonstrate that there might not exist assignments that satisfy standard fairness and non-wastefulness properties; whereas constrained non-wasteful assignments which are fair for same type students always exist. We introduce a "controlled" version of the deferred acceptance algorithm with an improvement stage (CDAAI) that finds a Pareto optimal assignment among such assignments. To achieve fair (across all types) and non-wasteful assignments, we propose the control constraints to be interpreted as soft bounds-flexible limits that regulate school priorities. In this setting, a modified version of the deferred acceptance algorithm (DAASB) finds an assignment that is Pareto optimal among fair assignments while eliciting true preferences. CDAAI and DAASB provide two alternative practical solutions depending on the interpretation of the control constraints. JEL C78, D61, D78, I20.

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We investigate the mixing-demixing transition and the collapse in a quasi-two-dimensional degenerate boson-fermion mixture (DBFM) with a bosonic vortex. We solve numerically a quantum-hydrodynamic model based on a new density functional which accurately takes into account the dimensional crossover. It is demonstrated that with the increase of interspecies repulsion, a mixed state of DBFM could turn into a demixed state. The system collapses for interspecies attraction above a critical value which depends on the vortex quantum number. For interspecies attraction just below this critical limit there is almost complete mixing of boson and fermion components. Such mixed and demixed states of a DBFM could be experimentally realized by varying an external magnetic field near a boson-fermion Feshbach resonance, which will result in a continuous variation of interspecies interaction.

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This paper presents two Variable Structure Controllers (VSC) for continuous-time switched plants. It is assumed that the state vector is available for feedback. The proposed control system provides a switching rule and also the variable structure control input. The design is based on Lyapunov-Metzler (LM) inequalities and also on Strictly Positive Real (SPR) systems stability results. The definition of Lyapunov-Metzler-SPR (LMS) systems and its direct application in the design of VSC for switched systems are introduced in this paper. Two examples illustrate the design of the proposed VSC, considering a plant given by a switched system with a switched-state control law and two linear time-invariant systems, that are not controllable and also can not be stabilized with state feedback. ©2008 IEEE.

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For every possible spectrum of 2(N)-dimensional density operators, we construct an N-qubit X-state of the same spectrum and maximal genuine multipartite (GM-) concurrence, hence characterizing a global unitary transformation that -constrained to output X-states-maximizes the GM-concurrence of an arbitrary input mixed state of N qubits. We also apply semidefinite programming methods to obtain N-qubit X-states with maximal GM-concurrence for a given purity and to provide an alternative proof of optimality of a recently proposed set of density matrices for the purpose, the so-called X-MEMS. Furthermore, we introduce a numerical strategy to tailor a quantum operation that converts between any two given density matrices using a relatively small number of Kraus operators. We apply our strategy to design short operator-sum representations for the transformation between any given N-qubit mixed state and a corresponding X-MEMS of the same purity.

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This article examines religious practices in the United States, which govern modesty and other dress norms for men. I focus both on the spaces within which they most collide with regulatory regimes of the state and the legal implications of these norms, particularly for observant Muslim men. Undergirding the research are those ‘‘gender equality’’ claims made by many religious adherents, that men are required to maintain proper modesty norms just as are women. Also undergirding the research is the extensive anti-Islam bias in American culture today. The spaces within which men’s religiously proscribed dress and grooming norms are most at issue—indicated by First Amendment legal challenges to rights of religious practice—are primarily those state-controlled, total institutions Goffman describes, such as in the military and prisons. The implications of gendered modesty norms are important, as state control over religious expression in prisons, for example, is much more difficult to contest than in other spaces, although this depends entirely on who is doing the contesting and within which religious context. In American society today—and particularly within the context of growing Islamaphobia following the 9/11 attacks—the implications are greatest for those men practicing ‘‘prison Islam.’’

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Bipolar mixed states combine depressive and manic features, presenting diagnostic and treatment challenges and reflecting a severe form of the illness. DSM-IV criteria for a mixed state require combined depressive and manic syndromes, but a range of mixed states has been described clinically. A unified definition of mixed states would be valuable in understanding their diagnosis, mechanism and treatment implications. We investigated the manner in which depressive and manic features combine to produce a continuum of mixed states. In 88 subjects with bipolar disorder (DSM-IV), we evaluated symptoms and clinical characteristics, and compared depression-based, mania-based, and other published definitions of mixed states. We developed an index of the extent to which symptoms were mixed (Mixed State Index, MSI) and characterized its relationship to clinical state. Predominately manic and depressive mixed states using criteria from recent literature, as well as Kraepelinian mixed states, had similar symptoms and MSI scores. Anxiety correlated significantly with depression scores in manic subjects and with mania scores in depressed subjects. Discriminant function analysis associated mixed states with symptoms of hyperactivity and negative cognitions, but not subjective depressive or elevated mood. High MSI scores were associated with severe course of illness. For depressive or manic episodes, characteristics of mixed states emerged with two symptoms of the opposite polarity. This was a cross-sectional study. Mixed states appear to be a continuum. An index of the degree to which depressive and manic symptoms combine appears useful in identifying and characterizing mixed states. We propose a depressive or manic episode with three or more symptoms of the opposite polarity as a parsimonious definition of a mixed state.

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Post-1949 Han migration to Xinjiang Uyghur Autonomous Region in northwest China is a hotly debated issue among the Xinjiang scholars and within the region itself. While it is often discussed using statistical data as a large-scale historical process, I argue in this article for a more differentiated view of Han migrants. I demonstrate that in the popular discourse migrants are distinguished into numerous categories like Bingtuaners , Profit-Driven Migrants, Border Supporters, Qualified Personnel, Educated Youth, and others. Accordingly, I argue that Han migrants to Xinjiang should not be understood as a homogeneous category of participants in a singular state project intended to establish state control over the region. High return rates demonstrate that state attempts to make Han settle in Xinjiang are only partly successful, and that migrants follow their own strategies when situation permits, rather than fulfill the government’s plans. Individuals who have migrated since the 1980s are especially careful in their assessment of the economic incentives of settlement, and many decide to remain mobile.

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Since 1991, policies of economic liberalization in Ethiopia have been effective in releasing the economy from rigid state control. At the same time, they have also exposed Ethiopian people to domestic and international free market competition. In African countries, the retreat of governments from rural development due to economic liberalization policies has led to the re-evaluation of the role of cooperatives. Since 1999, in Ethiopia, several coffee farmers cooperative unions have been established to support peasants who are handicapped by their lack of negotiating power in the global economy. Coffee cooperatives have become market-oriented and are now relatively democratic compared to the former Marxist cooperatives of the previous regime. Thus far, these coffee cooperatives have provided higher profits to coffee farmers than have private traders. The actual volume of purchase, however, is limited due to financial constraints. Because of this, the majority of cooperatives continues to rely on conventional marketing channels rather than on unions. Considering their weak financial condition, it is too early to judge the sustainability of the cooperatives because international prices have been high recently, and it is not yet clear how they would survive a downward international price trend.

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Ion channels underlying the electrical activity of neurons can be regulated by neurotransmitters via two basic mechanisms: ligand binding and covalent modification. Whereas neurotransmitters often act by binding directly to ion channels, the intracellular messenger cyclic AMP is thought usually to act indirectly, by activating protein kinase A, which in turn can phosphorylate channel proteins. Here we show that cyclic AMP, and transmitters acting via cyclic AMP, can act in a protein kinase A-independent manner in the brain. In hippocampal pyramidal cells, cyclic AMP and norepinephrine were found to cause a depolarization by enhancing the hyperpolarization-activated mixed cation current, IQ (also called Ih). This effect persisted even after protein kinase A activity was blocked, thus strongly suggesting a kinase-independent action of cyclic AMP. The modulation of this current by ascending monoaminergic fibers from the brainstem is likely to be a widespread mechanism, participating in the state control of the brain during arousal and attention.

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Korea is one of the world's most volatile areas, not least because traditional UN mediation and peacekeeping missions are impossible. Having intervened in the Korean War on behalf of the southern side, the UN is a party to the conflict, rather than a neutral arbiter. The situation is particularly problematic because political interactions are characterized by a high degree of state-control over security policy. In both parts of the peninsula the state has, at least until recently, exercised the exclusive right to deal with the opponent on the other side of the hermetically divided peninsula. Given these domestic and international constrains, alternative approaches to conflict resolution are urgently needed. The recently proliferating literature on human security offers possible solutions, for it urges policy makers to view security beyond the conventional military-based defence of the state and its territory. Using such a conceptual framework, the essay assesses the potential significance non-state interactions between North and South, particularly those that promote communication, information exchange and face-to-face encounters. Even though these interactions remain limited, they are of crucial importance, for they provide an opportunity to reduce the stereotypical threat images that continue to fuel conflict on the peninsula.

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We provide an easily computable formula for a bipartite mixed-state entanglement measure. Our formula can be applied to readily calculate the entanglement for any rank-2 mixed state of a bipartite system. We use this formula to provide a tight upper bound for the entanglement of formation for rank-2 states of a qubit and a qudit. We also outline situations where our formula could be applied to study the entanglement properties of complex quantum systems.

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This study explores the origins and development of honors education at a Historically Black College and University (HBCU), Morgan State University, within the context of the Maryland higher education system. During the last decades, public and private institutions have invested in honors experiences for their high-ability students. These programs have become recruitment magnets while also raising institutional academic profiles, justifying additional campus resources. The history of higher education reveals simultaneous narratives such as the tension of post-desegregated Black colleges facing uncertain futures; and the progress of the rise and popularity of collegiate honors programs. Both accounts contribute to tracing seemingly parallel histories in higher education that speaks to the development of honors education at HBCUs. While the extant literature on honors development at Historically White Institutions (HWIs) of higher education has gradually emerged, our understanding of activity at HBCUs is spotty at best. One connection of these two phenomena is the development of honors programs at HBCUs. Using Morgan State University, I examine the role and purpose of honors education at a public HBCU through archival materials and oral histories. Major unexpected findings that constructed this historical narrative beyond its original scope were the impact of the 1935/6 Murray v Pearson, the first higher education desegregation case. Other emerging themes were Morgan’s decades-long efforts to resist state control of its governance, Maryland’s misuse of Morrill Act funds, and the border state’s resistance to desegregation. Also, the broader histories of Black education, racism, and Black citizenship from Dred Scott and Plessy, the 1863 Emancipation Proclamation to Brown, inform this study. As themes are threaded together, Critical Race Theory provides the framework for understanding the emerging themes. In the immediate wake of the post-desegregation era, HBCUs had to address future challenges such as purpose and mission. Competing with HWIs for high-achieving Black students was one of the unanticipated consequences of the Brown decision. Often marginalized from higher education research literature, this study will broaden the research repository of honors education by documenting HBCU contributions despite a challenging landscape.

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This study identifies and compares competing policy stories of key actors involved in the Ecuadorian education reform under President Rafael Correa from 2007-2015. By revealing these competing policy stories the study generates insights into the political and technical aspects of education reform in a context where state capacity has been eroded by decades of neoliberal policies. Since the elections in 2007, President Correa has focused much of his political effort and capital on reconstituting the state’s authority and capacity to not only formulate but also implement public policies. The concentration of power combined with a capacity building agenda allowed the Correa government to advance an ambitious comprehensive education reform with substantive results in equity and quality. At the same time the concentration of power has undermined a more inclusive and participatory approach which are essential for deepening and sustaining the reform. This study underscores both the limits and importance of state control over education; the inevitable conflicts and complexities associated with education reforms that focus on quality; and the limits and importance of participation in reform. Finally, it examines the analytical benefits of understanding governance, participation and quality as socially constructed concepts that are tied to normative and ideological interests.

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Estudos apontam fatores que podem aumentar a longevidade; no entanto, muitas questões pertinentes a este tema ainda não foram elucidadas. Percepções do próprio longevo a respeito dos fatores contribuintes para longevidade são importantes, permitindo levantamento de cada fator e suas interações com demais variáveis que promovem a longevidade. O presente artigo relata dados da investigação sobre "o segredo da longevidade", segundo percepções dos próprios longevos, analisados pelo referencial metodológico da grounded theory. Foram entrevistados trinta ferroviários longevos do município de Botucatu (SP). A análise das falas dos longevos possibilitou determinar que a percepção dos fatores se aglutina em torno de categorias progressivamente abrangentes que culminam na representação coletiva de que a longevidade é dependente do embate entre fatores prejudiciais que aniquilam a vida e fatores saudáveis que geram e preservam a vida, sobre o qual a falta de controle social e do Estado torna pessimista a visão do futuro.