7,082 research outputs found

    An Assessment of Health-Economic Burden of Obesity Trends with Population-Based Preventive Strategies in a Developed Economy

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    The burden of obesity varies with age, ethnicity, socio-economic status and state economies. All new projections should hence accommodate population ageing, and other population changes such as immigration, health-care system reform, or technological advances for disease treatment for a comprehensible assessment of global burden. The unfordable and expensive nature for reversing the obesity tide arises from policies developed to combat obesity. Most of these approaches aim at bringing the problem under control, rather than affecting a cure, and obviously require a multi-disciplinary and intensive regimen. Prevention is the only feasible option and is essential for all affected countries. Yet it is not simple to have population based UK-wide strategic framework for tackling obesity. Besides existence of multiple layers of governance, there are clear demarcations between targets in diet; nutrition and physical activity level between regions some of which are not realistic. Population based approaches target policies and process, aiming for a transition towards healthy population diets, activity levels and weight status. It is essential to understand these aspects differ culturally and between and within countries. There are still no clear and appropriate answers about answer when, where, why, and, how costs accrue in obese populations, further long term commitments are required for the same. Most population-based prevention policies are cost effective, largely paying for themselves through future health gains and resulting reductions in health expenditures. Therefore these prevention programs should be high on the scientific and political agendas

    Microwave response of an HEMT photoconductor

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    Interdigitated photodetectors of various geometries have been fabricated on GaAlAs/GaAs heterostructure material. Optical response characteristics of these devices have been examined at both dc and microwave frequencies. The microwave response, at frequencies to 8 GHz, was studied by illuminating the devices with the output of an internally modulated GaAlAs diode laser. Results of these measurements are presented and compared with that of GaAs photoconductors

    Optical control of an 8-element Ka-band phased array using a high-speed optoelectronic interconnect

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    Optical distribution of control signals in electronically steered phased array antennas is being considered. A demonstration experiment is described in which a high speed hybrid GaAs optoelectronic integrated circuit (OEIC) was used to control an eight element phased array antenna. The OEIC, which accepts a serial optical control signal as input and converts it to 16 demultiplexed parallel outputs, was used to control the monolithic GaAs phase shifters of a Ka-band patch panel array antenna. Antenna pattern switching speeds of 2.25 microsec, limited by interface circuitry, were observed

    System architecture of MMIC-based large aperture arrays for space application

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    The persistent trend to use millimeter-wave frequencies for satellite communications presents the challenge to design large-aperture phased arrays for space applications. These arrays, which comprise 100 to 10,000 elements, are now possible due to the advent of lightwave technology and the availability of monolithic microwave integrated circuits. In this paper, system aspects of optically controlled array design are studied. In particular, two architectures for a 40 GHz array are outlined, and the main system-related issues are examined: power budget, synchronization in frequency and phase, and stochastic effects

    Photoresponse of YBa2Cu3O(7-delta) granular and epitaxial superconducting thin films

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    The response is reported of thin films of YBa2Cu3O(7-delta) with either a very grainy or a smooth epitaxial morphology to visible radiation. SrTiO3 substrates were employed for both types of films. The grainy films were formed by sequential multi-layer electron beam evaporation while the epitaxial films were formed by laser ablation. Both films were patterned into H shaped detectors via a negative photolithographic process employing a Br/ethanol etchant. The bridge region of the H was 50 microns wide. The patterned films formed by laser ablation and sequential evaporation had critical temperatures of 74 K and 72 K respectively. The bridge was current biased and illuminated with chopped He-Ne laser radiation and the voltage developed in response to the illumination was measured. A signal was detected only above the critical temperature and the peak of the response coincided with the resistive transition for both types of films although the correspondence was less exact for the grainy film. The details of the responses and their analysis are presented

    Progressive Damage and Failure Analysis of Bonded Composite Joints at High Energy Dynamic Impacts

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    Both wing and fuselage structures utilize bonded composite joints for structural efficiency in modern commercial and military aircraft. To ensure compliance with certification requirements mechanical fasteners are typically used as a failsafe mechanism for appropriate strength in the event of complete stiffener disbond. However, the use of fasteners decreases the structural efficiency of the structure by adding weight. This establishes the requirement to better exploit the efficiency of bonded structures and fully understand the failure behavior of adhesively bonded composite structures, particularly when subjected to elevated loading rates due to high energy dynamic impacts (HEDI). For this reason, the NASA Advanced Composite Consortium (ACC) HEDI team developed an experimentation and numerical modeling program for high rate loading of composite joints. In the present work, the response of adhesively bonded composite joints subjected to elevated loading rates is studied numerically and validated against experimental results. Due to dynamic considerations of experiments, the idea of wedge insert was extended to use with Split Hopkinson Pressure Bar (SHPB) testing techniques. Mode-I and Mode-II test configurations were simulated to evaluate the capability of two continuum damage material (CDM) models in LS-DYNA, namely MAT162 and MAT261. Three different levels of fidelity were considered to investigate the level of detail required to numerically predict the failure behavior and the results from high fidelity analysis are presented

    Measurement techniques for cryogenic Ka-band microstrip antennas

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    The measurement of cryogenic antennas poses unique logistical problems since the antenna under test must be embedded in a cooling chamber. A method of measuring the performance of cryogenic microstrip antennas using a closed cycle gas cooled refrigerator in a far field range is described. Antenna patterns showing the performance of gold and superconducting Ka-band microstrip antennas at various temperatures are presented

    Efimov states and their Fano resonances in a neutron-rich nucleus

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    Asymmetric resonances in elastic n+19^{19}C scattering are attributed to Efimov states of such neutron-rich nuclei, that is, three-body bound states of the n+n+18^{18}C system when none of the pairs is bound or some of them only weakly bound. By fitting to the general resonance shape described by Fano, we extract resonance position, width, and the "Fano profile index". While Efimov states have been discussed extensively in many areas of physics, there is only one very recent experimental observation in trimers of cesium atoms. The conjunction that we present of the Efimov and Fano phenomena may lead to experimental realization in nuclei.Comment: 4 double-column pages, 3 figure

    Recent developments on the ALICE central Trigger processor

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    The ALI CE Central Trigger Processor has been constructed and tested, and will shortly be installed in the experimental area. In this review, we introduce the new developments in hardware and software, present a measurement of the minimum propagation time, and illustrate various trigger applications
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