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Abstract  

This paper reports the results of instrumental neutron activation analysis (INAA) on 3,704 obsidian samples, taking the measurements of 23 elements. The results are summarized, combining the results of INAA conducted earlier by Ambiru et al. on 1,444 samples. The samples for these analyses are taken from seventy obsidian sources located at various places of Japan.

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Abstract  

Co-authored publications across sectors have been used as indicators of the triple helix model and more generally for the study of science–technology relations. However, how to measure the relationships among the three or more sectors is a technically difficult issue. Using mutual information as an indicator has proved to be effective, but it is not widely used. In this paper, we introduced φ coefficients and partial correlation as conventional indicators to measure the relationships among sectors on the basis of Japanese publication data in the ISI-databases. We also proposed a new approach of graphical modeling based on partial correlation for studying university–industry–government relationships and relationships with other sectors. The conventional indicators give results that are consistent with mutual information, which shows that collaborations among the three national sectors (U, I, G) are getting weaker and that members of these sectors tend to collaborate much more with foreign researchers. It is also shown that universities used to play the central role in the national publication system and acted as a bridge between national sectors and foreign researchers. However, since 2000, the situation has been changing. The center of the Japanese research network is becoming more “foreign” oriented.

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Abstract  

Indoor radon and thoron concentrations were dominated with their exhalation rate from building materials. Thus, the evaluation of exhalation rate with highly precise is important. This paper presented a new technique to measure the dependence radon/thoron exhalation rate, from building materials used in Japan, on absolute humidity. The measurement technique consisted of a solid state alpha detector equipped a ventilation-type chamber and humidity control system in a flow through method. The exhalation rate of dried samples (Indian red granite and Japanese gray granite) was measured at various absolute humidity levels in the range of 1–20 g cm−3. It was found that exhalation rate increased exponential with increasing of absolute humidity for both samples. Furthermore, the dependence of radon emanation coefficient on building material’s temperature was also studied using an accumulation chamber equipped with scintillation cell alpha detector. The emanation coefficient of dry sample increased proportionally with increasing the material’s temperature with a correlation factor of 0.88.

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Abstract  

The wet and dry deposition of gamma-emitting nuclides are presented for Tsukuba and eleven stations in Japan following the nuclear reactor accident at Chernobyl'. In Japan fallout from the reactor at Chernobyl' was first detected on May 3, 1986, a week after the accident. Abruptly high radioactive deposition, which mainly consists of131I,132I,103Ru,137Cs and134Cs, was observed in early May. The cumulative amount of131I,103Ru and137Cs in May at Tsukuba were 5854±838 Bq·m–2, 364±54 Bq·m–2 and 130±26 Bq·m–2 (decay was corrected to April 26), respectively. The monthly137Cs deposition in May corresponds to 2.5% of the cumulative137Cs deposition during the period from 1960 through 1982. Most of the Chernobyl' radioactivities, especially131I, are scavenged from the atmosphere by the wet removal process.

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Abstract  

Determination of ppm levels of B in 21 igneous and sedimentary rocks of the Japanese geochemical reference samples prepared by the Geological Survey of Japan (GSJ) has been performed by neutron-induced prompt γ-ray analysis (PGA) using cold and thermal guided neutron beams of the JRR-3M. Owing to the Doppler broadened γ-ray line of B 478 keV, many elements such as Na, Ni, Cl and so on showed spectral interference in the determination of B. The interference was corrected by computer fitting and a reference peak method. The analytical results obtained by the present method almost agreed with the GSJ values recommended in 1994 within the standard deviation of the recommended values. Sodium contents determined by the PGA in the reference rock samples are also reported.

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Abstract  

To determine the levels of210Pb and210Po in human tissues of people in Japan, various tissue samples were obtained at autopsy from the cadavers of 22 oncologic cases, mainly in Niigata Prefecture in northern Japan, from 1986 to 1988.Wet ashing, followed by electrochemical deposition and alpha spectrometry were used to separate and determine the210Pb and210Po present. Among the tissues analyzed, the highest concentrations of210Pb and210Po were observed in bone (sternum), liver, and kidneys. The total body burden of210Pb and210Po was found to be approximately 427 pCi and 514 pCi, respectively. This estimated210Po value did not differ significantly from values found in populations in the U.S.A. and European countries.

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Abstract  

210Pb and210Po in human hair have been measured to serve as an aid in order to estimate the dietary intake and body burden of these radionuclides of Japanese. The210Po concentrations found in 83 hair samples were ranging from 4.0 to 59.3 mBq/g with a mean (median) value of 18.2±12.2 (14.9) mBq/g as compared to the210Pb concentrations from 0.7 to 6.5 mBq/g with a mean (median) value of 2.3±1.1 (2.0) mBq/g. The210Po/210Pb activity ratios (mean: 8.7±5.1, median: 7.1) were surprisingly higher compared with the available literature value of about 2. The high concentration of210Po in human hair of Japanese may be due to the ingestion of animal protein mainly in the form of seafood.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: H. Muramatsu, S. Yoshizawa, T. Abe, T. Ishii, M. Wada, Y. Horiuchi, and R. Kanekatsu

Abstract  

The concentration of 7Be in surface air at Nagano City has been measured during the period from August 2000 to March 2005. The average monthly concentrations of 7Be in surface air were in the range of 3.3–14 mBq/m3 with pronounced two peaks in spring and autumn. It took 30–40 hours to recover the 7Be concentrations observed before, once 7Be was washed out by wet precipitations. For a pronounced increase in the concentrations of 7Be found in winter, a low-pressure trough coming close to the Japanese Islands with high concentrations of 7Be is responsible under the characteristic distribution of atmospheric pressure around the Japanese Islands.

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Summary  

The Japanese government has been attempting to reform the national research system for the past 20 years. This paper describes the structural changes of the system and its performance based on bibliometric analyses and discusses the effects of S&T policy. The investigation indicates that although Japan gradually increased its production of highly cited publications, its share of low-cited publications is much higher than the former. Detailed analyses reveal that the top eight universities account for half of the highly cited publications in the university sector, while other hundreds of universities have massively increased their low-cited publications since 1990. The development of financial and human resources for research in the 1990s enabled new actors to be involved in scientific research, but the resources were concentrated to a small number of universities, reinforcing the collaboration between these universities and others.

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Summary  

In this article we present an indicator - Probabilistic Partnership Index (PPI) - for use in measuring scientific linkages. This indicator is based on the Monte-Carlo simulation which provides a standard model to each network established in collaboration between two countries. Any relationship that occurs within a (whole) network can be projected to a standard model respectively and thus PPI is useful in examining individual networks within complex exchanges. We investigate inter-sectoral cooperation between France and Japan for the period of 1981-2004, by classifying every research unit appearing in the data set by its sector. We examine international collaborative patterns, domestic collaborative patterns and multilateral relationships established within the French-Japanese cooperation. We also compare PPI with the classic collaborative linkage indexes - Jaccard Index, Salton-Ochiai Index and Probabilistic Affinity Index - in order to describe the specificity of the new indicator. Our hope is that PPI will prove to be a useful and complementary tool for the analysis of international collaboration.

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