14,040 research outputs found

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

    Full text link
    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

    Is physical education relevant? Interpersonal skills, values and hybridity

    Get PDF
    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

    Model-independent Analyses of Dark-Matter Particle Interactions

    Get PDF
    A model-independent treatment of dark-matter particle elastic scattering has been developed, yielding the most general interaction for WIMP-nucleon low-energy scattering, and the resulting amplitude has been embedded in the nucleus, taking into account the selection rules imposed by parity and time-reversal. One finds that, in contrast to the usual spin-independent/spin-dependent (SI/SD) formulation, the resulting cross section contains six independent nuclear response functions, three of which are associated with possible velocity-dependent interactions. We find that current experiments are four orders of magnitude more sensitive to derivative couplings than is apparent in the standard SI/SD treatment, which necessarily associates such interactions with cross sections proportional to the square of the WIMP velocity relative to the nuclear center of mass.Comment: 10 pages, 2 figures; talk presented at TAUP201

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

    Full text link
    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

    Limit Theorems For Quantum Walks Associated with Hadamard Matrices

    Full text link
    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

    The Whole World in Your Hand: Active and Interactive Segmentation

    Get PDF
    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

    Get PDF
    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
    • ā€¦
    corecore