Hiroshima University

About: Hiroshima University is a education organization based out in Hiroshima, Japan. It is known for research contribution in the topics: Population & Cancer. The organization has 33602 authors who have published 69290 publications receiving 1495648 citations. The organization is also known as: Hiroshima Daigaku.

A New Attenuation Relation for Strong Ground Motion in Japan Based on Recorded Data

Abstract: Following the 1995 Hyogo-ken Nanbu Kobe. Earthquake, the Japanese government, in an effort to prevent future earthquake disasters, installed networks consisting of a large number of strong-motion observation stations. Further, national seismic hazard maps were made available to the public on an Internet website in March 2005 by the Headquarters for Earthquake Research Promotion. However, these maps indicate only the local seismic intensity for Japan, as empirically con- verted from predicted peak velocity in consolidated soils. For various applications, other strong-motion indexes such as the response spectral acceleration are required. In this study, a database of whole Japanese strong ground motion records between 1963 and 2003 is established in order to identify a new standard attenuation relation for Japan, for response acceleration as well as peak value. It is usually very difficult to determine a suitable model form due to the large variability of strong-motion data and correlation among the model variables, because the strong coupling of variables in an attenuation model, and the statistical power of the data is often not large enough to determine the necessity of these parameters. Therefore, in this study, our model has only three variables: earthquake magnitude, shortest distance to the seismic fault plane, and focal depth. To improve predictions given by the model, site correction terms are adopted and additional terms for correcting regional anomalous seismic intensity with respect to the base model are determined. The good fit between the model and observed strong-motion records suggests that the new model is reasonably robust.

Developmental defects of the ventromedial hypothalamic nucleus and pituitary gonadotroph in the Ftz‐F1 disrupted mice

Abstract: Ad4BP (or SF-1) has been iden- tified as a transcription factor which regulates all the steroidogenic P450 genes in the peripheral or- gans, and is encoded by the mammalian homo- logue of Drosophila FTZ-F1 gene. mRNA coding for Ad4BP was detected in the hypothalamus and pituitary of rats by RT-PCR. Immunohistochemi- cal analyses using an antiserum to Ad4BP in the brain and pituitary revealed that the transcrip- tion factor is expressed in nuclei of the dorso- medial part of the ventromedial hypothalamus (dmVMH) and in some subpopulation of the ade- nohypophysial cells. Double immunostaining of the pituitary for Ad4BP and trophic peptide hor- mones, FSH, TSH, and ACTH, indicated a re- stricted localization of Ad4BP to the gonadotroph. Disruption of the mouse Ftz-FI gene was clarified to induce severe defects in the organization of the dmVMH and the function of the pituitary gona- dotroph. However, some of the dm VMH neurons and pituitary gonadotrophs persisted, which pro- vided a sharp contrast to complete agenesis of the peripheral steroidogenic tissues (adrenal and go- nads) in the mutant mouse. Additional abnormal- ities were seen in the ventrolateral part of VMH and dorsomedial hypothalamic nucleus, both of which do not express Ad4BP but have strong reciprocal fiber-connections with the dmVMH. Aromatase P450-containing cells in the medial preoptico-amygdaloid region, which were devoid of Ad4BP, persisted even in the brain of the gene disrupted mice. The present results clearly showed that the hypothalamic and pituitary Ad4BPs are essential to normal development of the functional VMH and gonadotroph through some mechanism distinct from that in the periph-