1,514 research outputs found

    The Role of Licence-Exemption in Spectrum Reform

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    Spectrum reform initiatives in the US and Europe have identified a need to move away from the traditional command and control approach towards flexible and tradable licences and licence-exemption. Current regulatory initiatives are tending to focus on the flexible licensing route, and there is a risk that licence-exemption will be sidelined during the important formative years of this major policy transition. This must not happen; licence-exemption supports innovation and entrepreneurship and is an important second leg of a market-based spectrum management regime. A current case in point is the transition in UHF frequency bands from analogue to digital TV, where licence exempt use of resulting gaps in the spectrum could yield enormous benefits for citizens and consumers.spectrum policy, spectrum management, wireless services, deregulation, Telecommunications, regulation, Networks

    Measurement Via Optical Near-Nulling and Subaperture Stitching

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    A subaperture stitching interferometer system provides near-nulling of a subaperture wavefront reflected from an object of interest over a portion of a surface of the object. A variable optical element located in the radiation path adjustably provides near-nulling to facilitate stitching of subaperture interferograms, creating an interferogram representative of the entire surface of interest. This enables testing of aspheric surfaces without null optics customized for each surface prescription. The surface shapes of objects such as lenses and other precision components are often measured with interferometry. However, interferometers have a limited capture range, and thus the test wavefront cannot be too different from the reference or the interference cannot be analyzed. Furthermore, the performance of the interferometer is usually best when the test and reference wavefronts are nearly identical (referred to as a null condition). Thus, it is necessary when performing such measurements to correct for known variations in shape to ensure that unintended variations are within the capture range of the interferometer and accurately measured. This invention is a system for nearnulling within a subaperture stitching interferometer, although in principle, the concept can be employed by wavefront measuring gauges other than interferometers. The system employs a light source for providing coherent radiation of a subaperture extent. An object of interest is placed to modify the radiation (e.g., to reflect or pass the radiation), and a variable optical element is located to interact with, and nearly null, the affected radiation. A detector or imaging device is situated to obtain interference patterns in the modified radiation. Multiple subaperture interferograms are taken and are stitched, or joined, to provide an interferogram representative of the entire surface of the object of interest. The primary aspect of the invention is the use of adjustable corrective optics in the context of subaperture stitching near-nulling interferometry, wherein a complex surface is analyzed via multiple, separate, overlapping interferograms. For complex surfaces, the problem of managing the identification and placement of corrective optics becomes even more pronounced, to the extent that in most cases the null corrector optics are specific to the particular asphere prescription and no others (i.e. another asphere requires completely different null correction optics). In principle, the near-nulling technique does not require subaperture stitching at all. Building a near-null system that is practically useful relies on two key features: simplicity and universality. If the system is too complex, it will be difficult to calibrate and model its manufacturing errors, rendering it useless as a precision metrology tool and/or prohibitively expensive. If the system is not applicable to a wide range of test parts, then it does not provide significant value over conventional null-correction technology. Subaperture stitching enables simpler and more universal near-null systems to be effective, because a fraction of a surface is necessarily less complex than the whole surface (excepting the extreme case of a fractal surface description). The technique of near-nulling can significantly enhance aspheric subaperture stitching capability by allowing the interferometer to capture a wider range of aspheres. More over, subaperture stitching is essential to a truly effective near-nulling system, since looking at a fraction of the surface keeps the wavefront complexity within the capability of a relatively simple nearnull apparatus. Furthermore, by reducing the subaperture size, the complexity of the measured wavefront can be reduced until it is within the capability of the near-null design

    Steward Leadership

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    As a teacher, husband, father, grandfather, and friend, and with the Holy Spirit’s help, I really want to keep getting to know the Master more intimately so I can truly help those in my sphere of influence appreciate to their maximum potential as assets in God’s kingdom. Posting about Christian leadership from In All Things - an online hub committed to the claim that the life, death, and resurrection of Jesus Christ has implications for the entire world. http://inallthings.org/steward-leadership

    Assessing the Impact of the Mobile Assisted Career Exploration Unit 3 Years Later

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    The specific objective of this research was to determine if the MACE (Mobile Assisted Career Exploration) Program has had an effect on the realistic occupational decision-making ability of students after a period of 3 years. Subjects were 12th grade students at Dixie High School. The experimental group was composed of 40 students (15 males and 25 females) who had been involved in project MACE in the ninth grade. The control group was composed of 32 students (15 males and 1 7 females) who had moved into the boundaries of Dixie High School since the loth grade and who had, therefore, not been involved in the MACE Program. Both groups were administered the SVIB (Strong Vocational Interest Blanks) to determine their highest interests. Grades for both semesters of the 11th grade and the first semester of the 12th grade were collected as an indicator of each student\u27s strongest aptitudes. A questionnaire was administered wherein the student was required to 1) select an occupation that he was planning to enter; 2) report whether he thought his interest and aptitudes agreed with his job choice (the SVIB and grades were used as instruments to verify if a student\u27s interests and aptitudes did in fact agree with his job choice); 3) report the degree of certainty he felt about his job choice; 4) select the type of training that would be required to qualify for his job choice; 5) report a specific institution where such training could be acquired; 6) report those persons and/ or influencing factors which had lead up to his job selection; and 7) report at which grade level he had decided on his present job choice. Seven null hypotheses were formulated stating differences would not be found between the control and experimental groups on the criteria measured by the aforementioned measuring instruments. Results of the study indicate that in fact no difference was found between the experimental and control groups in the following areas tested. Correct identification of personal interests with job choice. Correct identification of personal aptitudes with job choice. Degree of certainty about job choice. Selection of the categories mobile van, parents and personal interests as being of assistance in making a job choice. Selection of the ninth and 10th grades as the time periods when job choice was made. Selection of an appropriate type of education or training for the student\u27s job choice. Selection of a specific and appropriate institution at which the student had made plans to obtain the training or education for his job choice. On the criteria measured, the MACE Program had no apparent longitudinal effect on the occupational decision-making ability (as defined in this study) of the students tested. Several limitations of the study should be considered in this conclusion: 1) sample size was small and limited to a rural, all-white population; 2) other measures may detect advantageous effects of the program. However, it is recommended that a program such as MACE be part of a total K-12 career development program rather than a one grade level experience

    The Role of Licence-Exemption in Spectrum Reform

    Get PDF
    Spectrum reform initiatives in the US and Europe have identified a need to move away from the traditional command and control approach towards flexible and tradable licences and licence-exemption. Current regulatory initiatives are tending to focus on the flexible licensing route, and there is a risk that licence-exemption will be sidelined during the important formative years of this major policy transition. This must not happen; licence-exemption supports innovation and entrepreneurship and is an important second leg of a market-based spectrum management regime. A current case in point is the transition in UHF frequency bands from analogue to digital TV, where licence exempt use of resulting gaps in the spectrum could yield enormous benefits for citizens and consumers

    The Role of Licence-Exemption in Spectrum Reform

    Get PDF
    Spectrum reform initiatives in the US and Europe have identified a need to move away from the traditional command and control approach towards flexible and tradable licences and licence-exemption. Current regulatory initiatives are tending to focus on the flexible licensing route, and there is a risk that licence-exemption will be sidelined during the important formative years of this major policy transition. This must not happen; licence-exemption supports innovation and entrepreneurship and is an important second leg of a market-based spectrum management regime. A current case in point is the transition in UHF frequency bands from analogue to digital TV, where licence exempt use of resulting gaps in the spectrum could yield enormous benefits for citizens and consumers

    Reliability and Validity of the 2002 and 2006 Chapel Hill Expert Surveys on Party Positioning

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    This research note reports on the 2002 and 2006 Chapel Hill expert surveys (CHES), which measure national party positioning on European integration, ideology, and several European Union (EU) and non-EU policies. The reliability of expert judgments is examined and the CHES data are cross-validated with data from the Comparative Manifesto Project, the 2003 Benoit-Laver expert survey and the 2002 Rohrschneider-Whitefield survey. The dataset is available on the CHES website

    The ASTRO-H X-ray Observatory

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    The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by the Institute of Space and Astronautical Science (ISAS). ASTRO-H will investigate the physics of the high-energy universe via a suite of four instruments, covering a very wide energy range, from 0.3 keV to 600 keV. These instruments include a high-resolution, high-throughput spectrometer sensitive over 0.3-2 keV with high spectral resolution of Delta E < 7 eV, enabled by a micro-calorimeter array located in the focal plane of thin-foil X-ray optics; hard X-ray imaging spectrometers covering 5-80 keV, located in the focal plane of multilayer-coated, focusing hard X-ray mirrors; a wide-field imaging spectrometer sensitive over 0.4-12 keV, with an X-ray CCD camera in the focal plane of a soft X-ray telescope; and a non-focusing Compton-camera type soft gamma-ray detector, sensitive in the 40-600 keV band. The simultaneous broad bandpass, coupled with high spectral resolution, will enable the pursuit of a wide variety of important science themes.Comment: 22 pages, 17 figures, Proceedings of the SPIE Astronomical Instrumentation "Space Telescopes and Instrumentation 2012: Ultraviolet to Gamma Ray

    Oral abstracts 1: SpondyloarthropathiesO1. Detecting axial spondyloarthritis amongst primary care back pain referrals

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    Background: Inflammatory back pain (IBP) is an early feature of ankylosing spondylitis (AS) and its detection offers the prospect of early diagnosis of AS. However, since back pain is very common but only a very small minority of back pain sufferers have ASpA or AS, screening of back pain sufferers for AS is problematic. In early disease radiographs are often normal so that fulfilment of diagnostic criteria for AS is impossible though a diagnosis of axial SpA can be made if MRI evidence of sacroiliitis is present. This pilot study was designed to indicate whether a cost-effective pick up rate for ASpA/early AS could be achieved by identifying adults with IBP stratified on the basis of age. Methods: Patients aged between 18 and 45 years who were referred to a hospital physiotherapy service with back pain of more than 3 months duration were assessed for IBP. All were asked to complete a questionnaire based on the Berlin IBP criteria. Those who fulfilled IBP criteria were also asked to complete a second short questionnaire enquiring about SpA comorbidities, to have a blood test for HLA-B27 and CRP level and to undergo an MRI scan of the sacroiliac joints. This was a limited scan, using STIR, diffusion-weighted, T1 and T2 sequences of the sacroiliac joints to minimize time in the scanner and cost. The study was funded by a research grant from Abbott Laboratories Ltd. Results: 50 sequential patients agreed to participate in the study and completed the IBP questionnaire. Of these 27 (54%) fulfilled criteria for IBP. Of these, 2 patients reported a history of an SpA comorbidity - 1 psoriasis; 1 ulcerative colitis - and 3 reported a family history of an SpA comorbidity - 2 psoriasis; 1 Crohn's disease. 4 were HLA-B27 positive, though results were not available for 7. Two patients had marginally raised CRP levels (6, 10 -NR ≤ 5). 19 agreed to undergo MRI scanning of the sacroiliac joints and lumbar spine; 4 scans were abnormal, showing evidence of bilateral sacroiliitis on STIR sequences. In all cases the changes met ASAS criteria but were limited. Of these 4 patients 3 were HLA-B27 positive but none gave a personal or family history of an SpA-associated comorbidity and all had normal CRP levels. Conclusions: This was a pilot study yielding only limited conclusions. However, it is clear that: Screening of patients referred for physiotherapy for IBP is straightforward, inexpensive and quick. It appears that IBP is more prevalent in young adults than overall population data suggest so that targeting this population may be efficient. IBP questionnaires could be administered routinely during a physiotherapy assessment. HLA-B27 testing in this group of patients with IBP is a suitable screening tool. The sacroiliac joint changes identified were mild and their prognostic significance is not yet clear so that the value of early screening needs further evaluation. Disclosure statement: C.H. received research funding for this study from Abbott. A.K. received research funding for this study, and speaker and consultancy fees, from Abbott. All other authors have declared no conflicts of interes
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