6,704 research outputs found
Supplement to MTI Study on Selective Passenger Screening in the Mass Transit Rail Environment, MTI Report 09-05
This supplement updates and adds to MTIs 2007 report on Selective Screening of Rail Passengers (Jenkins and Butterworth MTI 07-06: Selective Screening of Rail Passengers). The report reviews current screening programs implemented (or planned) by nine transit agencies, identifying best practices. The authors also discuss why three other transit agencies decided not to implement passenger screening at this time. The supplement reconfirms earlier conclusions that selective screening is a viable security option, but that effective screening must be based on clear policies and carefully managed to avoid perceptions of racial or ethnic profiling, and that screening must have public support. The supplement also addresses new developments, such as vapor-wake detection canines, continuing challenges, and areas of debate. Those interested should also read MTI S-09-01 Rail Passenger Selective Screening Summit
Photoproduction Processes in Polarized ep - Collisions at HERA
We study various conceivable photoproduction reactions in a polarized ep
collider mode of HERA with respect to their sensitivity to the proton's
polarized gluon distribution. A special emphasis is put on the `resolved' part
of the cross sections which in principle opens the possibility to determine for
the first time also the completely unknown parton content of longitudinally
polarized photons. In the very promising case of dijet production we also
investigate the impact of parton showering, hadronization and jet finding on
the parton level results.Comment: 16 pages, LaTeX, 7 figures, uses epsfig, amssymb, and a41 (included)
styles; Contribution to the proceedings of the 1997 workshop on 'Physics with
Polarized Protons at HERA', Hamburg and Zeuthen, Germany, March-September
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Depth sensitive sampling of implanted species in Genesis Collectors using UV laser ablation and SIMS
SIMS profiling of laser abalation pits in CVD diamond implanted with oxygen- 18 shows that homogenised 193nm excimer laser beam can successfully ablate a layer a few nm thick, removing surface contamination without signicant loss of implanted sample
The pulsation spectrum of VX Hydrae
We present the results of a two-year, multisite observing campaign
investigating the high-amplitude delta Scuti star VX Hydrae during the 2006 and
2007 observing seasons. The final data set consists of nearly 8500 V-band
observations spanning HJD 2453763.6 to 2454212.7 (2006 January 28 to 2007 April
22). Separate analyses of the two individual seasons of data yield 25
confidently-detected frequencies common to both data sets, of which two are
pulsation modes, and the remaining 23 are Fourier harmonics or beat frequencies
of these two modes. The 2006 data set had five additional frequencies with
amplitudes less than 1.5 mmag, and the 2007 data had one additional frequency.
Analysis of the full 2006-2007 data set yields 22 of the 25 frequencies found
in the individual seasons of data. There are no significant peaks in the
spectrum other than these between 0 and 60 c/d. The frequencies of the two main
pulsation modes derived from the 2006 and 2007 observing seasons individually
do not differ at the level of 3-sigma, and thus we find no conclusive evidence
for period change over the span of these observations. However, the amplitude
of f(1) = 5.7898 c/d changed significantly between the two seasons, while the
amplitude of f(0) = 4.4765 c/d remained constant; amplitudes of the Fourier
harmonics and beat frequencies of f(1) also changed. Similar behavior was seen
in the 1950s, and it is clear that VX Hydrae undergoes significant amplitude
changes over time.Comment: 14 pages, 5 figures, published in Publications of the Astronomical
Society of the Pacific, v.121, p.1076 (October 2009
Corrections to updated analyses of the results from the Island Closure Feasibility Study for the Dassen/Robben Island pair given in Appendix A of MARAM/IWS/DEC14/Peng/B12
DAFF have recently advised of detection of errors in the data agreed to be used to provide results from the island closure feasibility study to be presented to the Panel, as listed in document MARAM/IWS/DEC14/Peng/C1. This involves the recruit survey biomass series advised; the errors are corrected in a revised Table provided in MARAM/IWS/DEC14/Peng/C4. These errors affect only the results for method (iv) for Dassen and Robben Islands which were reported in Appendix A of
MARAM/IWS/DEC14/Peng/B12. These analyses have consequently been repeated with the corrected data
Dietary patterns and depressive symptoms over time: examining the relationships with socioeconomic position, health behaviours and cardiovascular risk
Recent research suggests that diet quality influences depression risk; however, a lack of experimental evidence leaves open the possibility that residual confounding explains the observed relationships. The aim of this study was to document the cross-sectional and longitudinal associations between dietary patterns and symptoms of depression and to undertake a detailed examination of potential explanatory factors, particularly socioeconomic circumstances, in the diet-depression relationship
A STATISTICAL MODEL FOR STOCK ASSESSMENT OF SOUTHERN BLUEFIN TUNA WITH TEMPORAL CHANGES IN SELECTIVITY
Assessment of the status of southern bluefin tuna (SBT) by Australia and Japan has used a method (ADAPT) that imposes a number of structural restrictions, and is similar to methods used for a number of stocks worldwide. A flexible method for assessment of the SBT population is presented that is much less restrictive and has potentially wide applicability. The three key features are: (1) all fitting to data is within the context of maximum likelihood, (2) catch-at-age data are not assumed to be without error (as in existing methods), but rather to be random variables, while age-specific selectivity is allowed to change over time within the bounds of specific structure, and (3) autocorrelation in recruitment processes is considered within the likelihood framework of the model. While the results suggest the stock has been depleted considerably from its virgin biomass, and are generally consistent with previous assessments, they also indicate that it is not as much below the biomass that will produce maximum suitable yield as previously estimated and that the extent of stock rebuilding necessary may not be as large as has been argued. The available data are shown to provide little information on the steepness parameter of the stock-recruitment function, and hence on sustainable catch levels for the stock.Afr. J. mar. Sci. 25: 331–36
A statistical model for stock assessment of southern bluefin tuna with temporal changes in selectivity
Assessment of the status of southern bluefin tuna (SBT) by Australia and Japan has used a method (ADAPT) that imposes a number of structural restrictions, and is similar to methods used for a number of stocks world-wide. A flexible method for assessment of the SBT population is presented that is much less restrictive and has potentially wide applicability. The three key features are: (1) all fitting to data is within the context of maximum likelihood, (2) catch-at-age data are not assumed to be without error (as in existing methods), but rather to be random variables, while age-specific selectivity is allowed to change over time within the bounds of specific structure, and (3) autocorrelation in recruitment processes is considered within the likelihood framework of the model. While the results suggest the stock has been depleted considerably from its virgin biomass, and are generally consistent with previous assessments, they also indicate that it is not as much below the biomass that will produce maximum suitable yield as previously estimated and that the extent of stock rebuilding necessary may not be as large as has been argued. The available data are shown to provide little information on the steepness parameter of the stock-recruitment function, and hence on sustainable catch levels for the stock
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