29,659 research outputs found

    3D body scanning and healthcare applications

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    Developed largely for the clothing industry, 3D body-surface scanners are transforming our ability to accurately measure and visualize a person's body size, shape, and skin-surface area. Advancements in 3D whole-body scanning seem to offer even greater potential for healthcare applications

    Anthropometry and body composition of 18 year old men according to duration of breast feeding: birth cohort study from Brazil

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    Objective: To assess the association between duration of breast feeding and measures of adiposity in adolescence. Design: Population based birth cohort study. Setting: Pelotas, a city of 320 000 inhabitants in a relatively developed area in southern Brazil. Participants: All newborn infants in the city's hospitals were enrolled in 1982; 78.8% (2250) of all male participants were located at age 18 years when enrolling in the national army. Main outcome measures: Weight, height, sitting height, subscapular and triceps skinfolds, and body composition (body fat, lean mass). Results: Neither the duration of total breast feeding nor that of predominant breast feeding (breast milk plus non-nutritive fluids) showed consistent associations with anthropometric or body composition indices. After adjustment for confounding factors, the only significant associations were a greater than 50% reduction in obesity among participants breast fed for three to five months compared with all other breastfeeding categories (P = 0.007) and a linear decreasing trend in obesity with increasing duration of predominant breast feeding (P = 0.03). Similar significant effects were not observed for other measures of adiposity. Borderline direct associations also occurred between total duration of breast feeding and adult height (P = 0.06). Conclusions: The significant reduction in obesity among children breast fed for three to five months is difficult to interpret, as no a priori hypothesis existed regarding a protective effect of intermediate duration of breast feeding. The findings indicate that, in this population, breast feeding has no marked protective effect against adolescent adiposity

    Random matrices and quantum spin chains

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    Random matrix ensembles are introduced that respect the local tensor structure of Hamiltonians describing a chain of nn distinguishable spin-half particles with nearest-neighbour interactions. We prove a central limit theorem for the density of states when n→∞n \rightarrow\infty, giving explicit bounds on the rate of approach to the limit. Universality within a class of probability measures and the extension to more general interaction geometries are established. The level spacing distributions of the Gaussian Orthogonal, Unitary and Symplectic Ensembles are observed numerically for the energy levels in these ensembles.Comment: Updated figures, as accepted in 'Markov Processes and Related Fields' on 3 March 201

    Spectra and eigenstates of spin chain Hamiltonians

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    We prove that translationally invariant Hamiltonians of a chain of nn qubits with nearest-neighbour interactions have two seemingly contradictory features. Firstly in the limit n→∞n\rightarrow\infty we show that any translationally invariant Hamiltonian of a chain of nn qubits has an eigenbasis such that almost all eigenstates have maximal entanglement between fixed-size sub-blocks of qubits and the rest of the system; in this sense these eigenstates are like those of completely general Hamiltonians (i.e. Hamiltonians with interactions of all orders between arbitrary groups of qubits). Secondly in the limit n→∞n\rightarrow\infty we show that any nearest-neighbour Hamiltonian of a chain of nn qubits has a Gaussian density of states; thus as far as the eigenvalues are concerned the system is like a non-interacting one. The comparison applies to chains of qubits with translationally invariant nearest-neighbour interactions, but we show that it is extendible to much more general systems (both in terms of the local dimension and the geometry of interaction). Numerical evidence is also presented which suggests that the translational invariance condition may be dropped in the case of nearest-neighbour chains.Comment: Updated figures, as accepted in 'Communications in Mathematical Physics' on 5 January 201

    EAGLE ISS - A modular twin-channel integral-field near-IR spectrograph

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    The ISS (Integral-field Spectrograph System) has been designed as part of the EAGLE Phase A Instrument Study for the E-ELT. It consists of two input channels of 1.65x1.65 arcsec field-of-view, each reconfigured spatially by an image-slicing integral-field unit to feed a single near-IR spectrograph using cryogenic volume-phase-holographic (VPH) gratings to disperse the image spectrally. A 4k x 4k array detector array records the dispersed images. The optical design employs anamorphic magnification, image slicing, VPH gratings scanned with a novel cryo-mechanism and a three-lens camera. The mechanical implementation features IFU optics in Zerodur, a modular bench structure and a number of high-precision cryo-mechanisms.Comment: 12 pages, to be published in Proc SPIE 7735: Ground-based & Airborne Instrumentation for Astronomy II

    NASA Green Flight Challenge: Conceptual Design Approaches and Technologies to Enable 200 Passenger Miles per Gallon

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    The Green Flight Challenge is one of the National Aeronautics and Space Administration s Centennial Challenges designed to push technology and make passenger aircraft more efficient. Airliners currently average around 50 passenger-miles per gallon and this competition will push teams to greater than 200 passenger-miles per gallon. The aircraft must also fly at least 100 miles per hour for 200 miles. The total prize money for this competition is $1.65 Million. The Green Flight Challenge will be run by the Comparative Aircraft Flight Efficiency (CAFE) Foundation September 25 October 1, 2011 at Charles M. Schulz Sonoma County Airport in California. Thirteen custom aircraft were developed with electric, bio-diesel, and other bio-fuel engines. The aircraft are using various technologies to improve aerodynamic, propulsion, and structural efficiency. This paper will explore the feasibility of the rule set, competitor vehicles, design approaches, and technologies used

    Who Owns the Local Church? A Pressing Issue for Dioceses in Bankruptcy

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    The recent bankruptcies of Catholic Dioceses are unprecedented. For the first time, Bankruptcy Courts must deal with the difficult question of who owns the parish church. In this paper, I will explore two possible sources of confusion about this question. The first is the non- commercial, charitable nature of the Church. The second is its organizational complexity. Resolving the confusion requires a familiarity with various different sources of law including charities law, bankruptcy law, trust law, and Canon Law. In this paper I address this issue by: 1. discussing why the equities and policies that govern charitable bankruptcies are different from those that govern commercial bankruptcies; 2. laying out a road map for determining ownership issues that indicates what sub-questions must be answered and in what order; and 3. discussing the role that each of the different sources of law plays in answering these questions. My conclusion is that, in most circumstances, individual parishes do have a significant ownership stake in assets that are given or dedicated for their use

    Do We Really Need 1001 Shifts for Energy Calibration?

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