13,020 research outputs found

    Technical management techniques for identification and control of industrial safety and pollution hazards

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    Constructive recommendations are suggested for pollution problems from offshore energy resources industries on outer continental shelf. Technical management techniques for pollution identification and control offer possible applications to space engineering and management

    The role of dietary polyphenols in the moderation of the inflammatory response in early stage colorectal cancer

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    Current focus in colorectal cancer management is on reducing overall mortality by increasing the number of early stage cancers diagnosed and treated with curative intent. Despite the success of screening programmes in down-staging colorectal cancer, interval cancer rates are substantial and other strategies are desirable. Sporadic colorectal cancer is largely associated with lifestyle factors including diet. Polyphenols are phytochemicals ingested as part of a normal diet which are abundant in plant foods including fruits/berries and vegetables. These may exert their anti-carcinogenic effects via the modulation of inflammatory pathways. Key signal transduction pathways are fundamental to the association of inflammation and disease progression including those mediated by NF-κB and STAT, PI3K and COX. Our aim was to examine the evidence for the effect of dietary polyphenols intake on tumour and host inflammatory responses to determine if polyphenols may be effective as part of a dietary intervention. There is good epidemiological evidence of a reduction in colorectal cancer risk from case-control and cohort studies assessing polyphenol intake. It would be premature to suggest a major public health intervention to promote their consumption however, dietary change is safe and feasible, emphasising the need for further investigation of polyphenols and colorectal cancer risk

    Paper Session III-C - Hawaii\u27s Initiatives in Space

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    Activities related to space exploration and development have been identified by many in Hawaii as offering unique opportunities for the State of Hawaii to broaden and diversify its economic base. Although there have been many space-related programs and projects underway in Hawaii, few realized the extent to which this had occurred. In February 1987, the Department of Business and Economic Development of the State of Hawaii asked Arthur D. Little, Inc., to evaluate Hawaii\u27s potential for more extensive efforts in connection with space. The study team evaluated world-wide developments and Hawaii\u27s competitive position in eight segments of space-related activities: satellite communication, remote sensing, navigation, space science, materials processing, on-orbit services, defense and launch services. Specific recommendations were put forth to enhance the State\u27s position. Further evaluation was conducted to select two alternative sites as possible locations for a commercial launch facility to be potentially developed on the island of Hawaii. An environmental impact statement and a master plan are being formulated as a precursor to development of one or the other site

    The measurement of low pay in the UK labour force survey

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    Consideration of the National Minimum Wage requires estimates of the distribution of hourly pay. The UK Labour Force Survey (LFS) is a key source of such estimates. The approach most frequently adopted by researchers has been to measure hourly earnings from several questions on pay and hours. The Office for National Statistics is now applying a new approach, based on an alternative more direct measurement introduced in March 1999. These two measures do not produce identical values and this paper investigates sources of discrepancies and concludes that the new variable is more accurate. The difficulty with using the new variable is that it is only available on a subset of respondents. An approach is developed in which missing values of the new variable are replaced by imputed values. The assumptions underlying this imputation approach and results of applying it to LFS data are presented. The relation to weighting approaches is also discussed

    Geophysics

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    Contains reports on three research projects

    Strong Enhancement of Superconducting Correlation in a Two-Component Fermion Gas

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    We study high-density electron-hole (e-h) systems with the electron density slightly larger than the hole density. We find a new superconducting phase, in which the excess electrons form Cooper pairs moving in an e-h BCS phase. The coexistence of the e-h and e-e orders is possible because e and h have opposite charges, whereas analogous phases are impossible in the case of two fermion species that have the same charge or are neutral. Most strikingly, the e-h order enhances the superconducting e-h order parameter by more than one order of magnitude as compared with that given by the BCS formula, for the same value of the effective e-e attractive potential \lambda^{ee}. This new phase should be observable in an e-h system created by photoexcitation in doped semiconductors at low temperatures.Comment: 5 pages including 5 PostScript figure

    The Size and Shape of Voids in Three-Dimensional Galaxy Surveys

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    The sizes and shapes of voids in a galaxy survey depend not only on the physics of structure formation, but also on the sampling density of the survey and on the algorithm used to define voids. Using an N-body simulation with a CDM power spectrum, we study the properties of voids in samples with different number densities of galaxies, both in redshift space and in real space. When voids are defined as regions totally empty of galaxies, their characteristic volume is strongly dependent on sampling density; when they are defined as regions whose density is 0.2 times the mean galaxy density, the dependence is less strong. We compare two void-finding algorithms, one in which voids are nonoverlapping spheres, and one, based on the algorithm of Aikio and Mahonen, which does not predefine the shape of a void. Regardless of the algorithm chosen, the characteristic void size is larger in redshift space than in real space, and is larger for low sampling densities than for high sampling densities. We define an elongation statistic Q which measures the tendency of voids to be stretched or squashed along the line of sight. Using this statistic, we find that at sufficiently high sampling densities (comparable to the number densities of galaxies brighter than L_*), large voids tend to be slightly elongated along the line of sight in redshift space.Comment: LaTex, 21 pages (including 7 figures), ApJ, submitte

    Fundamental Discreteness Limitations of Cosmological N-Body Clustering Simulations

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    We explore some of the effects that discreteness and two-body scattering may have on N-body simulations with ``realistic'' cosmological initial conditions. We use an identical subset of particles from the initial conditions for a 1283128^3 Particle-Mesh (PM) calculation as the initial conditions for a variety P3^3M and Tree code runs. We investigate the effect of mass resolution (the mean interparticle separation) since most ``high resolution'' codes only have high resolution in gravitational force. The phase-insensitive two--point statistics, such as the power spectrum (autocorrelation) are somewhat affected by these variations, but phase-sensitive statistics show greater differences. Results converge at the mean interparticle separation scale of the lowest mass-resolution code. As more particles are added, but the force resolution is held constant, the P3^3M and the Tree runs agree more and more strongly with each other and with the PM run which had the same initial conditions. This shows high particle density is necessary for correct time evolution, since many different results cannot all be correct. However, they do not so converge to a PM run which continued the fluctuations to small scales. Our results show that ignoring them is a major source of error on comoving scales of the missing wavelengths. This can be resolved by putting in a high particle density. Since the codes never agree well on scales below the mean comoving interparticle separation, we find little justification for quantitative predictions on this scale. Some measures vary by 50%, but others can be off by a factor of three or more. Our results suggest possible problems with the density of galaxy halos, formation of early generation objects such as QSO absorber clouds, etc.Comment: Revised version to be published in Astrophysical Journal. One figure changed; expanded discussion, more information on code parameters. Latex, 44 pages, including 19 figures. Higher resolution versions of Figures 10-15 available at: ftp://kusmos.phsx.ukans.edu/preprints/nbod

    Cosmic Voids and Galaxy Bias in the Halo Occupation Framework

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    (Abridged) We investigate the power of void statistics to constrain galaxy bias and the amplitude of dark matter fluctuations. We use the halo occupation distribution (HOD) framework to describe the relation between galaxies and dark matter. After choosing HOD parameters that reproduce the mean space density n_gal and projected correlation function w_p measured for galaxy samples with M_r<-19 and M_r<-21 from the Sloan Digital Sky Survey (SDSS), we predict the void probability function (VPF) and underdensity probability function (UPF) of these samples by populating the halos of a large, high-resolution N-body simulation. If we make the conventional assumption that the HOD is independent of large scale environment at fixed halo mass, then models constrained to match n_gal and w_p predict nearly identical void statistics, independent of the scatter between halo mass and central galaxy luminosity or uncertainties in HOD parameters. Models with sigma_8=0.7 and sigma_8=0.9 also predict very similar void statistics. However, the VPF and UPF are sensitive to environmental variations of the HOD in a regime where these variations have little impact on w_p. For example, doubling the minimum host halo mass in regions with large scale (5 Mpc/h) density contrast delta<-0.65 has a readily detectable impact on void probabilities of M_r<-19 galaxies, and a similar change for delta<-0.2 alters the void probabilities of M_r<-21 galaxies at a detectable level. The VPF and UPF provide complementary information about the onset and magnitude of density- dependence in the HOD. By detecting or ruling out HOD changes in low density regions, void statistics can reduce systematic uncertainties in the cosmological constraints derived from HOD modeling, and, more importantly, reveal connections between halo formation history and galaxy properties.Comment: emulateapj, 16 pages, 13 figure
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