1,932 research outputs found
The prominent role of the heaviest fragment in multifragmentation and phase transition for hot nuclei
The role played by the heaviest fragment in partitions of multifragmenting
hot nuclei is emphasized. Its size/charge distribution (mean value,
fluctuations and shape) gives information on properties of fragmenting nuclei
and on the associated phase transition.Comment: 11 pages, Proceedings of IWND09, August 23-25, Shanghai (China
Comparison of year-of-exam- and age-matched estimates of heritability in the Framingham Heart Study data
Several different approaches can be used to examine generational and temporal trends in family studies. The measurement of offspring and parents can be made over a short period of time with parents and offspring having quite different ages, or measurements can be made at the same ages but with decades between parent and offspring measures. A third approach, used in the Framingham Heart Study, has repeated examinations across a broad range of age and time, and provides a unique opportunity to compare these approaches. Parents and offspring were matched both on (year of exam) and on age. Heritability estimates for systolic blood pressure, body mass index, height, weight, cholesterol, and glucose were obtained by regressing offspring on midparent values with and without adjustment for age. Higher estimates of heritability were obtained for age-matched than for year-of-exam-matched data for all traits considered. For most traits, estimates of the heritability of the change over time (slope) of the trait were near zero. These results suggest that the optimal design to identify genetic effects in traits with large age-related effects may be to measure parents and offspring at similar ages and not to rely on age-adjustment or longitudinal measures to account for these temporal effects
Genetic association study of UCMA/GRP and OPTN genes (PDB6 locus) with Paget's disease of bone
We performed a genetic association study of rare variants and single nucleotide polymorphisms (SNPs) of UCMA/GRP and OPTN genes, in French-Canadian patients with Paget's disease of bone (PDB) and in healthy controls from the same population. We reproduced the variant found in the UCMA/GRP basal promoter and tested its functionality using in vitro transient transfection assays. Interestingly, this SNP rs17152980 appears to affect the transcription level of UCMA/GRP. In addition, we have identified five rare genetic variants in UCMA/GRP gene, four of them being population-specific, although none were found to be associated with PDB. Six Tag SNPs of UCMA/GRP gene were associated with PDB, particularly the SNP rs17152980 (uncorrected P = 3.8 x 10(-3)), although not significant after Bonferroni's correction. More importantly, we replicated the strong and statistically significant genetic association of two SNPs of the OPTN gene, the rs1561570 (uncorrected P = 5.7 x 10(-7)) and the rs2095388 (uncorrected P = 4.9 x 10(-3)), With PDB. In addition, we identified a very rare variant found to be located close to the basal promoter of the OPTN gene, at -232 bp from its distal transcription start site. Furthermore, depending on the type of allele present (G or A), the binding of several important nuclear factors such as the vitamin D or the retinoic acid receptors is predicted to be altered at this position, suggesting a significant effect in the regulation of transcription of the OPTN gene. In conclusion, we identified a functional SNP located in the basal promoter of the UCMA/GRP gene which provided a weak genetic association with PDB. In addition, we replicated the strong genetic association of two already known SNPs of the OPTN gene, with PDB in a founder effect population. We also identified a very rare variant in the promoter of OPTN, and through bioinformatic analysis, identified putative transcription factor binding sites likely to affect OPTN gene transcription. (C) 2012 Elsevier Inc. All rights reserved.Fonds de la Recherche du Quebec - Sante (FRQS), Canada; Portuguese Science and Technology Foundation, Portugal [SFRH/BPD/48206/2008]; Catalyst Grant (Bone Health) from the Canadian Institutes of Health Research (Canada); CHUQ Foundation (Canada); Groupe de Recherche en Maladies Osseuses (Canada); Canadian Foundation for Innovation (Canada); FRSQ (Canada); Laval University (Canada); CHUQ (CHUL) Research Centre (Canada); Centre of Marine Sciences (CCMAR) (Portugal)info:eu-repo/semantics/publishedVersio
Correspondence between genomic- and genealogical/coalescent-based inference of homozygosity by descent in large French-Canadian genealogies
Research on the genetics of complex traits overwhelmingly focuses on the additive effects of genes. Yet, animal studies have shown that non-additive effects, in particular homozygosity effects, can shape complex traits. Recent investigations in human studies found some significant homozygosity effects. However, most human populations display restricted ranges of homozygosity by descent (HBD), making the identification of homozygosity effects challenging. Founder populations give rise to higher HBD levels. When deep genealogical data are available in a founder population, it is possible to gain information on the time to the most recent common ancestor (MRCA) from whom a chromosomal segment has been transmitted to both parents of an individual and in turn to that individual. This information on the time to MRCA can be combined with the time to MRCA inferred from coalescent models of gene genealogies. HBD can also be estimated from genomic data. The extent to which the genomic HBD measures correspond to the genealogical/coalescent measures has not been documented in founder populations with extensive genealogical data. In this study, we used simulations to relate genomic and genealogical/coalescent HBD measures. We based our simulations on genealogical data from two ongoing studies from the French-Canadian founder population displaying different levels of inbreeding. We simulated single-nucleotide polymorphisms (SNPs) in a 1-Mb genomic segment from a coalescent model in conjunction with the observed genealogical data. We compared genealogical/coalescent HBD to two genomic methods of HBD estimation based on hidden Markov models (HMMs). We found that genomic estimates of HBD correlated well with genealogical/coalescent HBD measures in both study genealogies. We described generation time to coalescence in terms of genomic HBD estimates and found a large variability in generation time captured by genomic HBD when considering each SNP. However, SNPs in longer segments were more likely to capture recent time to coalescence, as expected. Our study suggests that estimating the coalescent gene genealogy from the genomic data to use in conjunction with observed genealogical data could provide valuable information on HBD
Fragment properties of fragmenting heavy nuclei produced in central and semi-peripheral collisions
Fragment properties of hot fragmenting sources of similar sizes produced in
central and semi-peripheral collisions are compared in the excitation energy
range 5-10 AMeV. For semi-peripheral collisions a method for selecting compact
quasi-projectiles sources in velocity space similar to those of fused systems
(central collisions) is proposed. The two major results are related to
collective energy. The weak radial collective energy observed for
quasi-projectile sources is shown to originate from thermal pressure only. The
larger fragment multiplicity observed for fused systems and their more
symmetric fragmentation are related to the extra radial collective energy due
to expansion following a compression phase during central collisions. A first
attempt to locate where the different sources break in the phase diagram is
proposed.Comment: 23 pages submitted to NP
Multifragmentation and phase transition for hot nuclei
5 pages, Proceedings of NN2009, August 17-21, Beijing (China)Recent important progress on the knowledge of multifragmentation and phase transition for hot nuclei, thanks to the high detection quality of the INDRA array, is reported. It concerns i) the radial collective energies involved in hot fragmenting nuclei/sources produced in central and semi- peripheral collisions and their influence on the observed fragment partitions, ii) a better knowledge of freeze-out properties obtained by means of a simulation based on all the available experimental information and iii) the quantitative study of the bimodal behaviour of the heaviest fragment distribution for fragmenting hot heavy quasi-projectiles which allows the extraction, for the first time, of an estimate of the latent heat of the phase transition
Bianchi Type V Viscous Fluid Cosmological Models in Presence of Decaying Vacuum Energy
Bianchi type V viscous fluid cosmological model for barotropic fluid
distribution with varying cosmological term is investigated. We have
examined a cosmological scenario proposing a variation law for Hubble parameter
in the background of homogeneous, anisotropic Bianchi type V space-time.
The model isotropizes asymptotically and the presence of shear viscosity
accelerates the isotropization. The model describes a unified expansion history
of the universe indicating initial decelerating expansion and late time
accelerating phase. Cosmological consequences of the model are also discussed.Comment: 10 pages, 3 figure
Quality assessment of health management information system (HMIS) data for maternal and child health in Jimma zone, Ethiopia
Health management information system (HMIS) data underpin attainment of health targets in low- and middle-income countries. However, the quality of HMIS data is often poor. The study appraised the completeness, timeliness, and internal consistency of eight key maternal and child health (MCH) indicators collected for all the primary health care units (PHCUs) located within three districts of Jimma Zone, Ethiopia. Results show that the HMIS may over-report the coverage of key MCH services, namely, antenatal care, skilled birth attendance and postnatal care. The quality of data at the zonal level could be improved to inform MCH research and programmatic efforts.Global Affairs Canada (GAC)Canadian institutes of Health Research (CIHR
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