53 research outputs found

    Behavior of the giant-dipole resonance in 120^{120}Sn and 208^{208}Pb at high excitation energ

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    The properties of the giant-dipole resonance (GDR) are calculated as a function of excitation energy, angular momentum, and the compound nucleus particle decay width in the nuclei 120^{120}Sn and 208^{208}Pb, and are compared with recent experimental data. Differences observed in the behavior of the full-width-at-half-maximum of the GDR for 120^{120}Sn and 208^{208}Pb are attributed to the fact that shell corrections in 208^{208}Pb are stronger than in 120^{120}Sn, and favor the spherical shape at low temperatures. The effects shell corrections have on both the free energy and the moments of inertia are discussed in detail. At high temperature, the FWHM in 120^{120}Sn exhibits effects due to the evaporation width of the compound nucleus, while these effects are predicted for 208^{208}Pb.Comment: 28 pages in RevTeX plus eight postscript figures. Submitted to Nucl. Phys.

    Shell Model for Warm Rotating Nuclei

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    In order to provide a microscopic description of levels and E2 transitions in rapidly rotating nuclei with internal excitation energy up to a few MeV, use is made of a shell model which combines the cranked Nilsson mean-field and the residual surface delta two-body force. The damping of collective rotational motion is investigated in the case of a typical rare-earth nucleus, namely \Yb. It is found that rotational damping sets in at around 0.8 MeV above the yrast line, and the levels which form rotational band structures are thus limited. We predict at a given rotational frequency existence of about 30 rotational bands of various lengths, in overall agreement with the experimental findings. The onset of the rotational damping proceeds quite gradually as a function of the internal excitation energy. The transition region extends up to around 2 MeV above yrast and it is characterized by the presence of scars of discrete rotational bands which extend over few spin values and stand out among the damped transitions, and by a two-component profile in the EγEγE_\gamma -E_\gamma correlation. The important role played by the high-multipole components of the two-body residual interaction is emphasized.Comment: 28 pages, LaTe

    Meta-analysis of type 2 Diabetes in African Americans Consortium

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    Type 2 diabetes (T2D) is more prevalent in African Americans than in Europeans. However, little is known about the genetic risk in African Americans despite the recent identification of more than 70 T2D loci primarily by genome-wide association studies (GWAS) in individuals of European ancestry. In order to investigate the genetic architecture of T2D in African Americans, the MEta-analysis of type 2 DIabetes in African Americans (MEDIA) Consortium examined 17 GWAS on T2D comprising 8,284 cases and 15,543 controls in African Americans in stage 1 analysis. Single nucleotide polymorphisms (SNPs) association analysis was conducted in each study under the additive model after adjustment for age, sex, study site, and principal components. Meta-analysis of approximately 2.6 million genotyped and imputed SNPs in all studies was conducted using an inverse variance-weighted fixed effect model. Replications were performed to follow up 21 loci in up to 6,061 cases and 5,483 controls in African Americans, and 8,130 cases and 38,987 controls of European ancestry. We identified three known loci (TCF7L2, HMGA2 and KCNQ1) and two novel loci (HLA-B and INS-IGF2) at genome-wide significance (4.15 × 10(-94)<P<5 × 10(-8), odds ratio (OR)  = 1.09 to 1.36). Fine-mapping revealed that 88 of 158 previously identified T2D or glucose homeostasis loci demonstrated nominal to highly significant association (2.2 × 10(-23) < locus-wide P<0.05). These novel and previously identified loci yielded a sibling relative risk of 1.19, explaining 17.5% of the phenotypic variance of T2D on the liability scale in African Americans. Overall, this study identified two novel susceptibility loci for T2D in African Americans. A substantial number of previously reported loci are transferable to African Americans after accounting for linkage disequilibrium, enabling fine mapping of causal variants in trans-ethnic meta-analysis studies.Peer reviewe

    Novel Loci for Adiponectin Levels and Their Influence on Type 2 Diabetes and Metabolic Traits : A Multi-Ethnic Meta-Analysis of 45,891 Individuals

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    J. Kaprio, S. Ripatti ja M.-L. Lokki työryhmien jäseniä.Peer reviewe

    Applications of HUGIN to Diagnosis and Control of Autonomous Vehicles

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    Abstract. We present an application of HUGIN to solve problems related to diagnosis and control of autonomous vehicles. The application is based on a distributed architecture supporting diagnosis and control of autonomous units. The purpose of the architecture is to assist the operator or piloting system in managing fault detection, risk assessment, and recovery plans under uncertainty. To handle uncertainty, we focus on the use of probabilistic graphical models (PGMs) as implemented in the HUGIN tool. We describe the application of PGMs to three problems of diagnosis and control of autonomous vehicles. Based on the HUGIN tool, limited memory influence diagrams (LIMIDs) are used to represent and solve complex problems of diagnosis and control of autonomous ground and underwater vehicles. In particular, we describe how battery monitoring and control problems related to an underwater and a ground vehicle are solved and how to solve the problem of assessing the quality of a sonar image related to an underwater vehicle.

    Sand Deposits Offshore Oahu, Hawaii

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    The value of sand as aggregate for concrete for the construction industry and as sediment for artificial beach replenishment at tourist destinations on Oahu has increased following a legislative moratorium on the mining of beach sand. Concern for future shortfalls of sand supply prompted prospecting for offshore deposits. Sand channels extend offshore from major valleys and coastal embayments on Oahu. Most of these accumulations join sinuous deposits of sediment ponded on ancient terraces that parallel the coastline. Sand cores were collected from these mapped deposits. Statistical analysis of particle size distributions of 279 samples from these cores reveals local areas that are promising for future exploitation. In some areas, variations of grain size can be related to water depth and distance from shore, but in most areas, grain sizes are not simply related to the geographic distribution of sampled sand. Along the leeward Oahu coast, size distributions are related to depth in core : 5 ft of fine sand covers medium and coarse sand. Comparisons between samples from different locales reveals relationships primarily to submarine geomorphology and secondarily to coastal wave climate
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