17,041 research outputs found

    Ortelius\u27s Map of the World and Homann\u27s Ship Model Map

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    Abraham Ortelius and Johann Baptist Homann were very successful cartographers who benefitted from the rising trend in curiosity cabinets during the Renaissance. Ortelius lived from 1527-1598 and was born in Antwerp, Belgium, and Homann became famous in Nuremberg, Germany during his life from 1663-1724. [excerpt

    Limit Theorems For Quantum Walks Associated with Hadamard Matrices

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    We study a one-parameter family of discrete-time quantum walk models on the line and in the xy-plane associated with the Hadamard walk. Weak convergence in the long-time limit of all moments of the walker's pseudo-velocity on the line and in the xy-plane is proved. Symmetrization on the line and in the xy-plane is theoretically investigated, leading to the resolution of the Konno-Namiki-Soshi conjecture in the special case of symmetrization of the unbiased Hadamard walk on the line . A necessary condition for the existence of a phenomenon known as localization is given

    Model-independent WIMP Scattering Responses and Event Rates: A Mathematica Package for Experimental Analysis

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    The community's reliance on simplified descriptions of WIMP-nucleus interactions reflects the absence of analysis tools that integrate general theories of dark matter with standard treatments of nuclear response functions. To bridge this gap, we have constructed a public-domain Mathematica package for WIMP analyses based on our effective theory formulation. Script inputs are 1) the coefficients of the effective theory, through which one can characterize the low-energy consequences of arbitrary ultraviolet theories of WIMP interactions; and 2) one-body density matrices for commonly used targets, the most compact description of the relevant nuclear physics. The generality of the effective theory expansion guarantees that the script will remain relevant as new ultraviolet theories are explored; the use of density matrices to factor the nuclear physics from the particle physics will allow nuclear structure theorists to update the script as new calculations become available, independent of specific particle-physics contexts. The Mathematica package outputs the resulting response functions (and associated form factors) and also the differential event rate, once a galactic WIMP velocity profile is specified, and thus in its present form provides a complete framework for experimental analysis. The Mathematica script requires no a priori knowledge of the details of the non-relativistic effective field theory or nuclear physics, though the core concepts are reviewed here and in arXiv:1203.3542.Comment: 30+6 page

    Is physical education relevant? Interpersonal skills, values and hybridity

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    Discussion surrounding the relevance of the document Health and Physical Education in the New Zealand Curriculum has focused on a range of areas. While some writers claim it has the potential to be emancipatory and the inclusion of interpersonal skills and values is important and meaningful, others have levelled criticisms that the document is trying to do too much and has a middle class agenda. This article reports part of the findings of a small study which explored how some Maori and Pasifika students viewed their experiences of physical education in one major urban New Zealand high school. The experiences of these students are related to Besley's notion of hybridity. Her argument suggests that young people actively negotiate and make critical decisions about what they think is relevant to them. The students believed physical education has provided them with opportunities to develop and practice care for others and to learn and apply interpersonal skills as well as to gain confidence and apply their skills in situations outside the school setting. The study argues the need for curriculum to connect with the wider lives of students and any degree of connection can only occur if students are given a voice in the curriculum implementation process

    The Whole World in Your Hand: Active and Interactive Segmentation

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    Object segmentation is a fundamental problem in computer vision and a powerful resource for development. This paper presents three embodied approaches to the visual segmentation of objects. Each approach to segmentation is aided by the presence of a hand or arm in the proximity of the object to be segmented. The first approach is suitable for a robotic system, where the robot can use its arm to evoke object motion. The second method operates on a wearable system, viewing the world from a human's perspective, with instrumentation to help detect and segment objects that are held in the wearer's hand. The third method operates when observing a human teacher, locating periodic motion (finger/arm/object waving or tapping) and using it as a seed for segmentation. We show that object segmentation can serve as a key resource for development by demonstrating methods that exploit high-quality object segmentations to develop both low-level vision capabilities (specialized feature detectors) and high-level vision capabilities (object recognition and localization)

    Lessons from crossing symmetry at large N

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    20 pages, v2: Assumptions stated more clearly, version published in JHEPWe consider the four-point correlator of the stress tensor multiplet in N=4 SYM. We construct all solutions consistent with crossing symmetry in the limit of large central charge c ~ N^2 and large g^2 N. While we find an infinite tower of solutions, we argue most of them are suppressed by an extra scale \Delta_{gap} and are consistent with the upper bounds for the scaling dimension of unprotected operators observed in the numerical superconformal bootstrap at large central charge. These solutions organize as a double expansion in 1/c and 1/\Delta_{gap}. Our solutions are valid to leading order in 1/c and to all orders in 1/\Delta_{gap} and reproduce, in particular, instanton corrections previously found. Furthermore, we find a connection between such upper bounds and positivity constraints arising from causality in flat space. Finally, we show that certain relations derived from causality constraints for scattering in AdS follow from crossing symmetry.Peer reviewe

    The impact of private sector provision on equitable provision of coronary revascularisation

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    Objective: To investigate the impact of including private sector data on assessments of equity of coronary revascularisation provision using NHS data only. Design: Analyses of Hospital Episodes Statistics and private sector data by age, sex, and PCT of residence. For each PCT, the share of London's total population and revascularisations (all admissions, NHS-funded, and privately-funded admissions) were calculated. GINI coefficients were derived to provide an index of inequality across sub-populations, with parametric bootstrapping to estimate confidence intervals. Setting: London Participants London residents undergoing coronary revascularisation April 2001 - December 2003. Intervention Coronary artery bypass graft or angioplasty Main outcome measures: Directly-standardised revascularisation rates, GINI coefficients. Results: NHS-funded age-standardised revascularisation rates varied from 95.2 to 193.9 per 100,000 and privately funded procedures from 7.6 to 57.6. Although the age distribution did not vary by funding, the proportion of revascularisations among women that were privately funded (11.0%) was lower than among men (17.0%). Privately funded rates were highest in PCTs with the lowest death rates (p=0.053). NHS-funded admission rates were not related to deprivation nor age-standardised deaths rates from coronary heart disease. Privately-funded admission rates were lower in more deprived PCTs. NHS provision was significantly more egalitarian (Gini coefficient 0.12) than the private sector (0.35). Including all procedures was significantly less equal (0.13) than NHS funded care alone. Conclusion: Private provision exacerbates geographical inequalities. Those responsible for commissioning care for defined populations must have access to consistent data on provision of treatment wherever it takes place

    An analysis of the shapes of interstellar extinction curves. VII Milky Way spectrophotometric optical-through-ultraviolet extinction and its R-dependence

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    We produce a set of 72 NIR-through-UV extinction curves by combining new Hubble Space Telescope/STIS optical spectrophotometry with existing International Ultraviolet Explorer spectrophotometry (yielding gapless coverage from 1150 to 10000 ?) and NIR photometry. These curves are used to determine a new, internally consistent NIR-through-UV Milky Way mean curve and to characterize how the shapes of the extinction curves depend on R(V). We emphasize that while this dependence captures much of the curve variability, considerable variation remains that is independent of R(V). We use the optical spectrophotometry to verify the presence of structure at intermediate wavelength scales in the curves. The fact that the optical-through-UV portions of the curves are sampled at relatively high resolution makes them very useful for determining how extinction affects different broadband systems, and we provide several examples. Finally, we compare our results to previous investigations

    BRIEF COMMUNICATION The projection of species distribution models

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