2,317 research outputs found

    Inhibition of monocyte complement receptor enhancement by low molecular weight material from human lung cancers

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    We have studied the effect of dialysates from lung cancer homogenates to alter both the expression of complement (C3b) receptors per se and also to inhibit leucoattractant-induced enhancement of complement rosettes on monocytes from healthy individuals. Enhancement and enhancement-inhibition by tumour extracts were compared with material derived from normal lung excised from distance from the tumour. There was no significant difference between tumour homogenate (TH) and normal lung homogenate (NLH) in terms of enhancement of complement rosettes per se. In contrast, TH produced a dose- and time-dependent inhibition of leucoattractant-induced enhancement of C3b rosettes which was significantly different from that obtained with NLH. This enhancement-inhibition was observed with four undifferentiated, four squamous and three adenocarcinomas of lung. The degree of enhancement-inhibition was not related to the type of tumour or varying accompanying histological features such as necrosis and the degree of infiltration with inflammatory cells. Following gel filtration on Sephadex G-50 each type of cancer gave a major peak of inhibitory activity which eluted with molecules having an apparent molecular size of approximately 3,000 daltons. A second larger peak (8,000-10,000 daltons) was also detected with extracts from the undifferentiated and adenocarcinomas. These results support previous findings, mainly from experimental animals, indicating that 'anti-macrophage/monocyte principles' are elaborated from certain tumour types

    The Effect of Breeding Herd Parity Structure on Genetic Improvement of the Sow Herd

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    This study focuses on the value of the genetic lag associated with maintaining sows for additional parities in a commercial swine herd. Three traits were included in this study: number born alive (NBA), 21 day litter weight (W21), and days to market (D250). The economic values assigned to these traits were 22.00/pig,22.00/pig, 0.70/lb., and 0.17/day,respectively.Thegeneticimprovementpergenerationmadeforeachtraitwasassumedtobe0.3pigs,3.0lbs.,and3.0days,respectively.ItwasestimatedthatthevalueofthegeneticlagassociatedwithretainingasowtoP3,P5,andP7was0.17/day, respectively. The genetic improvement per generation made for each trait was assumed to be 0.3 pigs, 3.0 lbs., and 3.0 days, respectively. It was estimated that the value of the genetic lag associated with retaining a sow to P3, P5, and P7 was 24.80, 46.89,and46.89, and 73.97 in a herd whose seedstock supplier has a generation interval of 1.5 years. This minimal loss does not justify the costs of developing a gilt and decreased P1 production. Therefore, sows should remain in the breeding herd until culling for non-voluntary reasons or inferior production becomes necessary

    Establishing uranium migration parameters for the Indian Springs Range

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    For the past 24 years, depleted uranium (DU) kinetic energy penetrators used by the US Air Force have been tested and evaluated to develop targeting system algorithms at a site in the Mojave Desert. This two-fold study focused on reducing uncertainties in the environmental parameters used to model DU migration in arid soils through extensive soil characterization; and evaluated potential horizontal migration of DU through close examination of erosion tracts traversing the target area. Model error reduction was achieved by developing site-specific parameters for DU migration on various impacted soil horizons. Parameters determined in this work included distribution coefficients, soil texture, soil pH, uranium activity concentration, and soil particle density, as well as characterization of motile playa layers subject to sporadic flash flooding events. Using these values in the Residual Radiation (RESRAD) computer code resulted in an individual\u27s first year total dose of 35 mrem under a resident farmer scenario. A sensitivity analysis was performed on several parameters, identifying the soil distribution coefficient (Kd) and density as the most significant to source removal and dose reduction. Data generated from RESRAD provided 238U soil clean up criterion of 200 pCi g-1 for decommissioning based on agricultural land usage requirements, and a limit on the sum of exposures from all model pathways to 25 mrem per year. Observations were made validating DU transport by erosion with activity concentration decreasing exponentially with distance. Recommendations are made to help mitigate the DU surface transport processes

    A development of logistics management models for the Space Transportation System

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    A new analytic queueing approach was described which relates stockage levels, repair level decisions, and the project network schedule of prelaunch operations directly to the probability distribution of the space transportation system launch delay. Finite source population and limited repair capability were additional factors included in this logistics management model developed specifically for STS maintenance requirements. Data presently available to support logistics decisions were based on a comparability study of heavy aircraft components. A two-phase program is recommended by which NASA would implement an integrated data collection system, assemble logistics data from previous STS flights, revise extant logistics planning and resource requirement parameters using Bayes-Lin techniques, and adjust for uncertainty surrounding logistics systems performance parameters. The implementation of these recommendations can be expected to deliver more cost-effective logistics support

    Fast symplectic map tracking for the CERN Large Hadron Collider

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    Tracking simulations remain the essential tool for evaluating how multipolar imperfections in ring magnets restrict the domain of stable phase-space motion. In the Large Hadron Collider (LHC) at CERN, particles circulate at the injection energy, when multipole errors are most significant, for more than 10^{7} turns, but systematic tracking studies are limited to a small fraction of this total time—even on modern computers. A considerable speedup is expected by replacing element-by-element tracking with the use of a symplectified one-turn map. We have applied this method to the realistic LHC lattice, version 6, and report here our results for various map orders, with special emphasis on precision and speed

    Behavioral correlates between daily activity and sociality in wild and captive origin African lions

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    Study of behavioral correlations within and across populations has long been of interest to ethologists. An exploration of behavioral correlations between sociality and behavior of African lions (Panthera leo) was undertaken to examine if this approach is better able to reveal important aspects of lion behavior not easily discernible by looking at these behaviors separately. Resting behavior and received play interactions were correlated in 2 captive-origin prides and one wild pride, attributable to the involvement of cubs and sub-adults. Direct and exploratory movement was negatively correlated with groom centrality in 2 of the 3 prides, due to adults engaging in high levels of both of these activities. Exploration of these behavioral correlations highlighted the differences between age-groups in activity and sociality, facilitating the understanding of the complex behavior and interactions of lions. In addition, the finding of similar behavioral correlations between captive-origin and the wild prides provides confidence in the suitability if captive-origin candidates for ex-situ release. This is imperative to ensure the success of sub-groups and prides under an ex-situ reintroduction program

    Clusters and Superclusters in the Las Campanas Redshift Survey

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    Two-dimensional high-resolution density field of galaxies of the Las Campanas Redshift Survey (LCRS) with a smoothing length 0.8 Mpc/h is used to extract clusters and groups of galaxies, and a low-resolution field with a smoothing length 10 Mpc/h to find superclusters of galaxies. Properties of these density field (DF) clusters and superclusters are studied and compared with the properties of Abell clusters and superclusters, and LCRS loose groups. We calculate the DF-cluster luminosity function, and show that most luminous clusters in high-density environments are about ten times brighter than most luminous clusters in low-density environments. We present a catalogue of DF-superclusters and show that superclusters that contain Abell clusters are richer and more luminous than superclusters without Abell clusters. A pdf file of the paper with high-resolution figures is available in Tartu Observatory web-site (http://www.aai.ee/~maret/cosmoweb.html)Comment: 19 pages LaTeX text, 15 PostScript Figures, submitted to Astronomy and Astrophysic

    Luminous superclusters: remnants from inflation

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    We derive the luminosity and multiplicity functions of superclusters compiled for the 2dF Galaxy Redshift Survey, the Sloan Digital Sky Survey (Data Release 4), and for three samples of simulated superclusters. We find for all supercluster samples Density Field (DF) clusters, which represent high-density peaks of the class of Abell clusters, and use median luminosities/masses of richness class 1 DF-clusters to calculate relative luminosity/mass functions. We show that the fraction of very luminous (massive) superclusters in real samples is more than tenfolds greater than in simulated samples. Superclusters are generated by large-scale density perturbations which evolve very slowly. The absence of very luminous superclusters in simulations can be explained either by non-proper treatment of large-scale perturbations, or by some yet unknown processes in the very early Universe.Comment: 6 pages, 3 Figures, submitted for Astronomy and Astrophysic

    The Accuracy of Referral for Portable Lipid Analyzers in an Old Order Mennonite Population

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    The primary purposes of this study were to: 1) examine the accuracy for referral of two portable lipid analyzers (PLAs) in an old order Mennonite population through a comparison to a national standardized reference laboratory, 2) examine the relationship of total cholesterol values with other known cardiovascular risk factors, and 3) foster the continued participatory model of health care service in this community. The self-selected sample was composed of 42 adult members of an old order Mennonite community residing in south central Kentucky. A descriptive correlational design was used in this study. There were clinically relevant variations in the total cholesterol and LDL-C in both of the analyzers. Additionally, there was a correlation between total cholesterol values and age. The study also facilitated the participatory model used with this community previously as the community members assisted in planning, implementing, and evaluating this project
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