1,949 research outputs found

    An Alternative to Developmental Coursework: Critical Skill Integration

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    This interactive session explores ways in which an associate degree liberal arts and sciences department eliminated developmental coursework through the integration of critical skills (reading, reasoning, thinking and math) into the core curriculum. We will discuss the importance of honoring disciplinary perspectives while also considering how best to deliver a core for associate degree adult learners

    How to observe a non-Kerr spacetime

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    We present a generic criterion which can be used in gravitational-wave data analysis to distinguish an extreme-mass-ratio inspiral into a Kerr background spacetime from one into a non-Kerr background spacetime. The criterion exploits the fact that when an integrable system, such as the system that describes geodesic orbits in a Kerr spacetime, is perturbed, the tori in phase space which initially corresponded to resonances disintegrate so as to form the so called Birkhoff chains on a surface of section, according to the Poincar\'{e}-Birkhoff theorem. The KAM curves of these islands in such a chain share the same ratio of frequencies, even though the frequencies themselves vary from one KAM curve to another inside an island. On the other hand, the KAM curves, which do not lie in a Birkhoff chain, do not share this characteristic property. Such a temporal constancy of the ratio of frequencies during the evolution of the gravitational-wave signal will signal a non-Kerr spacetime which could then be further explored.Comment: 4 pages, 2 figure

    The non-integrability of the Zipoy-Voorhees metric

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    The low frequency gravitational wave detectors like eLISA/NGO will give us the opportunity to test whether the supermassive compact objects lying at the centers of galaxies are indeed Kerr black holes. A way to do such a test is to compare the gravitational wave signals with templates of perturbed black hole spacetimes, the so-called bumpy black hole spacetimes. The Zipoy-Voorhees (ZV) spacetime (known also as the γ\gamma spacetime) can be included in the bumpy black hole family, because it can be considered as a perturbation of the Schwarzschild spacetime background. Several authors have suggested that the ZV metric corresponds to an integrable system. Contrary to this integrability conjecture, in the present article it is shown by numerical examples that in general ZV belongs to the family of non-integrable systems.Comment: 10 pages, 13 figure

    Dynamics and constraints of the Unified Dark Matter flat cosmologies

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    We study the dynamics of the scalar field FLRW flat cosmological models within the framework of the Unified Dark Matter (UDM) scenario. In this model we find that the main cosmological functions such as the scale factor of the Universe, the scalar field, the Hubble flow and the equation of state parameter are defined in terms of hyperbolic functions. These analytical solutions can accommodate an accelerated expansion, equivalent to either the dark energy or the standard Λ\Lambda models. Performing a joint likelihood analysis of the recent supernovae type Ia data and the Baryonic Acoustic Oscillations traced by the SDSS galaxies, we place tight constraints on the main cosmological parameters of the UDM cosmological scenario. Finally, we compare the UDM scenario with various dark energy models namely Λ\Lambda cosmology, parametric dark energy model and variable Chaplygin gas. We find that the UDM scalar field model provides a large and small scale dynamics which are in fair agreement with the predictions by the above dark energy models although there are some differences especially at high redshifts.Comment: 11 pages, 7 figures, published in Physical Review D, 78, 083509, (2008

    Regional Human Rights Regimes: A Comparison and Appraisal

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    For Americans at least, active concern for human rights on the international plane is demonstrated perhaps most conspicuously in the promotion and protection of human rights through the United Nations and its allied agencies--apart, that is, from the promotion and protection of human rights through United States foreign policy and the work of such nongovernmental organizations as Amnesty International. Supplementing this globally-oriented human rights activity, however, are international human rights regimes operating regionally in Western Europe, the Americas, Africa and the Middle East. Concededly, Asia is not yet represented, and only the first three of the represented regions have gone so far as to create enforcement mechanisms within the framework of a human rights charter, as evidenced by the European Convention for the Protection of Human Rights and Fundamental Freedoms and the European Social Charter, the American Convention on Human Rights and the Banjul (African) Charter on Human and Peoples\u27 Rights. The Permanent Arab Commission on Human Rights, founded by the Council of the League of Arab States in September 1968 but since then understandably preoccupied by the rights of Palestinian Arabs in and to the Israeli-occupied territories, has yet to bring a proposed Arab Convention on Human Rights to successful conclusion, and so far has tended to function more in terms of the promotion than the protection of human rights. Nevertheless, the regional development of human rights norms, institutions and procedures is likely to grow. Already an important dynamic of international human rights law and policy, it is, in any event, here to stay

    Developing a framework for the analysis of power through depotentia

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    Stakeholder participation in tourism policy-making is usually perceived as providing a means of empowerment. However participatory processes drawing upon stakeholders from traditionally empowered backgrounds may provide the means of removing empowerment from stakeholders. Such an outcome would be in contradiction to the claims that participatory processes improve both inclusivity and sustainability. In order to form an understanding of the sources through which empowerment may be removed, an analytical perspective has been developed deriving from Lukes�s views of power dating from 1974. This perspective considers the concept of depotentia as the removal of �power to� without speculating upon the underlying intent and also provides for the multidimensionality of power to be examined within a single study. The application of this analytical perspective has been tested upon findings of the government-commissioned report of the Countryside and Community Research Unit in 2005. The survey and report investigated the progress of Local Access Forums in England created in response to the Countryside and Rights of Way Act 2000. Consideration of the data from this perspective permits the classification of individual sources of depotentia which can each be addressed and potentially enable stakeholder groups to reverse loss of empowerment where it has occurred
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