6,016 research outputs found

    Leading From the Middle: Mid-Level District Staff and Instructional Improvement

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    This three-year research project demonstrates that mid-level central office staff can make or break critical reform initiatives. It also provides strong recommendations for a new vision of leadership in which central office and school staff become equal partners

    Tracing Through Scalar Entanglement

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    As a toy model of a gapped system, we investigate the entanglement entropy of a massive scalar field in 1+1 dimensions at nonzero temperature. In a small mass m and temperature T limit, we put upper and lower bounds on the two largest eigenvalues of the covariance matrix used to compute the entanglement entropy. We argue that the entanglement entropy has exp(-m/T) scaling in the limit m >> T. We comment on the relation between our work and the Ryu-Takayanagi proposal for computing the entanglement entropy holographically.Comment: 17 pages, 11 figures; v2 ref added, typos fixed; v3 refs added, minor clarifications, version to appear in PR

    Thermal Corrections to R\'enyi entropies for Free Fermions

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    We calculate thermal corrections to R\'{e}nyi entropies for free massless fermions on a sphere. More specifically, we take a free fermion on R×Sd1\mathbb{R}\times\mathbb{S}^{d-1} and calculate the leading thermal correction to the R\'{e}nyi entropies for a cap like region with opening angle 2θ2\theta. By expanding the density matrix in a Boltzmann sum, the problem of finding the R\'{e}nyi entropies can be mapped to the problem of calculating a two point function on an nn sheeted cover of the sphere. We follow previous work for conformal field theories to map the problem on the sphere to a conical region in Euclidean space. By using the method of images, we calculate the two point function and recover the R\'{e}nyi entropies.Comment: 15 pages, 5 figure

    Integrating gender into index-based agricultural insurance: a focus on South Africa

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    Index insurance is an agricultural risk management tool that can provide a safety net for smallholder farmers experiencing climate risk. While uptake and scale-out of index insurance may be slow among smallholders, we can learn from experiences that demonstrate where crop insurance can protect smallholders’ livelihoods from climate risk. Integrating gender into climate risk management is necessary to ensure that the benefits of index insurance are experienced by both men and women. A dedicated intention to integrate gender may be required. Taking South Africa as a case study, the potential for gender-sensitive index insurance scale-out among smallholders is investigated

    Phase Transitions and Conductivties of Floquet Fluids

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    We investigate the phase structure and conductivity of a relativistic fluid in a circulating electric field with a transverse magnetic field. This system exhibits behavior similar to other driven systems such as strongly coupled driven CFTs [Rangamani2015] or a simple anharmonic oscillator. We identify distinct regions of fluid behavior as a function of driving frequency, and argue that a "phase" transition will occur. Such a transition could be measurable in graphene, and may be characterized by sudden discontinuous increase in the Hall conductivity. The presence of the discontinuity depends on how the boundary is approached as the frequency or amplitude is dialed. In the region where two solution exists the measured conductivity will depend on how the system is prepared.Comment: v2: corrected typos and updated reference

    An insight into the impact of arable farming on Irish biodiversity: A scarcity of studies hinders a rigorous assessment

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    peer-reviewedTo help understand and counteract future agronomic challenges to farmland biodiversity, it is essential to know how present farming practices have affected biodiversity on Irish farms. We present an overview of existing research data and conclusions, describing the impact of crop cultivation on biodiversity on Irish arable farms. An extensive literature review clearly indicates that peer-reviewed publications on research conducted in Ireland on this topic are quite scarce: just 21 papers investigating the effect of conventional crop cultivation on Irish biodiversity have been published within the past 30 years. Principally, these studies have concluded that conventional crop cultivation has had an adverse impact on biodiversity on Irish farms, with 15 of the 21 studies demonstrating negative trends for the taxa investigated. Compared to other EU states, the relative dearth of baseline data and absence of monitoring programmes designed to assess the specific impacts of crop cultivation on Irish biodiversity highlight the need to develop long-term research studies. With many new challenges facing Irish agriculture, a research programme must be initiated to measure current levels of biodiversity on arable land and to assess the main farming ‘pressures’ causing significant biodiversity loss or gains in these systems.This work was funded under the EPA ERTDI Research Programme (Grant 2006-B-MS-46)

    The Failure of Whiteness in Art Education: A Personal Narrative Informed by Critical Race Theory

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    This article explores failure from the perspective of a white art educator interested in social justice and educational equity. Interconnected notions of failure are explored, including: the author’s learning from personal failure as a process of professional growth over the course of her career; the specter of “school failure” and its impact on K-12 students’ educational opportunities and experiences; entrenched, systemic inequities in public schools and their failure to serve marginalized students and communities; and the potential complicity of the author’s individual professional failures – if left unaddressed – in perpetuating racialized inequities in art education. Whiteness, or white power, knowledge, and privilege, is implicit in all these failures, both in the ways it shapes the uneven landscape of public education and in the author’s own process of professional growth as an art educator. The article is structured as a personal narrative that highlights salient professional failures over three phases of the author’s career, including: her early years as an elementary art teacher in a low-income African American community in Florida; her work as a doctoral student, which was informed by critical race theory; and her evolving practice as a university art educator working with racially diverse pre-service teachers

    Impact of introducing human immunodeficiency virus testing, treatment and care in a tuberculosis clinic in rural Kenya

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    SETTING: In July 2005, Médecins Sans Frontières and the Ministry of Health, Kenya, implemented an integrated tuberculosis-human immunodeficiency virus (TB-HIV) programme in western Kenya. OBJECTIVE: To evaluate the impact of an integrated TB-HIV programme on patient care and TB programme outcomes. DESIGN: Retrospective evaluation of three time periods: before (January-June 2005), shortly after (January-June 2006) and medium term after (January-December 2007) the implementation of the integrated programme. RESULTS: Respectively 79% and 91% of TB patients were HIV tested shortly and at medium term after service integration. The HIV-positive rate varied from 96% before the intervention to respectively 88% (305/347) and 74% (301/405) after. The estimated number of HIV-positive cases was respectively 303, 323 and 331 in the three periods. The proportion of patients receiving cotrimoxazole prophylaxis increased significantly from 47% (142/303) to 94% (303/323) and 86% (285/331, P < 0.05). Before the intervention, 87% (171/197) of the TB-HIV patients would have been missed when initiating antiretroviral treatment, compared to respectively 29% (60/210) and 36% (78/215) after the integration. The TB programme success rate increased from 56% (230/409) to 71% (319/447) in the third period (P < 0.05); however, there was no significant decrease in the default rate: 20% to 22% (P = 0.66) and 18% (P = 0.37). CONCLUSION: Integrated TB-HIV care has a very positive impact on the management of TB-HIV patients and on TB treatment outcomes

    Demonstration of ultra-high-Q small mode volume toroid microcavities on a chip

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    Optical microcavities confine light spatially and temporally and find application in a wide range of fundamental and applied studies. In many areas, the microcavity figure of merit is not only determined by photon lifetime (or the equivalent quality-factor, Q), but also by simultaneous achievement of small mode volume V . Here we demonstrate ultra-high Q-factor small mode volume toroid microcavities on-a-chip, which exhibit a Q/V factor of more than 106(λ/n)310^{6}(\lambda/n)^{-3}. These values are the highest reported to date for any chip-based microcavity. A corresponding Purcell factor in excess of 200 000 and a cavity finesse of 2.8×1062.8\times10^{6} is achieved, demonstrating that toroid microcavities are promising candidates for studies of the Purcell effect, cavity QED or biochemical sensingComment: 4 pages, 3 figures, Submitted to Applied Physics Letter
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