116 research outputs found

    Chemical and Rb-Sr isotopic features of the shock-melted chondrite Yamato-793533

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    The Sr isotopic compositions and Rb and Sr abundances, as well as major element abundances in olivine, pyroxenes and glass, were determined for a chip and 21 fractions separated from a shock-melted chondrite Yamato-793533, a dark-colored, porous stone with glassy texture. Two lithologies were recognized for the 1.5g specimen studied (Yamato-793533, 67) ; L (Main portion) and L to LL (Dark portion) chondritic in terms of chemical compositions of olivine and pyroxenes. The chemical compositions of glass are relatively homogeneous (SiO2=67-77%) compared to those of other ordinary chondrites, suggesting a moderate cooling rate after shock-melting. The data points for fractions do not foem any isochron in a 87Rb/86Sr vs. 87Sr/86Sr diagram. However, it is noted that six out of nine points for the dark portion plot around a 1.2 Ga line, while most of points for the main portion plot around a 4.55 Ga chondrite isochron. The observed difference could be responsible for difference in melting degrees between the two portions. Similar Rb-Sr features have been found among shock-melted Yamato-79 LL-chondrites which are considered to be paired stones experienced the same shock-melting event at 1.2 Ga. Consequently, the Rb-Sr systematics as well as petrologic features strongly suggest that Yamato-793533 is a member of a series of the shock-melted Yamato-79 LL-chondrites

    Development of complex hydrides for fast ionic conduction

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    Complex hydrides have been attracting much attention as solid-state fast ionic conductors since we reported the fast lithium ionic conduction in LiBH4 [1]. The development of fast ionic conductors is important because of their potential applications as solid electrolytes in rechargeable batteries [2]. We have worked on the development of lithium ionic conductors as well as sodium ionic conductors of complex hydrides. Please click Additional Files below to see the full abstract

    How do gall-forming social aphids keep their closed nest clean?

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    Interactive technology assessment (iTA) provides an answer to the ethical problem of normative bias in evaluation research. This normative bias develops when relevant perspectives on the evaluand (the thing being evaluated) are neglected. In iTA this bias is overcome by incorporating different perspectives into the assessment. As a consequence, justification of decisions based on the assessment is provided by stakeholders having achieved agreement. In this article, agreement is identified with wide reflective equilibrium to show that it indeed has the potential of justifying decisions. We work out several conditions for this agreement to be achievable and just

    When to help juveniles, adults, or both: analyzing the evolutionary models of stage-structured mutualism

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    Mutualism is common in nature and is crucial for population dynamics, community structure, and ecosystem functioning. Studies have recently pointed out that life-history stage structure (e.g., juveniles and adults) is a key factor to better understand the ecological consequences of mutualism (termed stage-structured mutualism). Despite the potential importance, little is known about what kinds of stage-structured mutualism can evolve and when it is likely to occur. Here, we theoretically investigated how a mutualistic partner species should allocate efforts of mutualistic associations for different life-history stages of its host species to maximize its fitness. We assessed the partner’s optimal strategy by using a one host–one partner model with the host’s juvenile-adult stage structure. The results showed that different forms of stage-structured mutualism can evolve, such as juvenile-specialized association, adult-specialized association, and inter-stage partner sharing (i.e., the partner associates with both the juvenile and adult stages of the host) depending on the shape of association trade-off, i.e., how much association with one stage is weakened when the partner strengthens its association with the other stage. In general, stage-specialized association (either juvenile-specialized or adult-specialized association) tends to evolve when being associated with that stage is relatively beneficial. Meanwhile, when the association trade-off is weak, inter-stage partner sharing can occur if the mutualistic benefits of juvenile-specific and adult-specific associations are sufficiently large. We also found that when the association trade-off is strong, alternative stable states occur in which either juvenile-specialized or adult-specialized associations evolve depending on the initial trait value. These results suggest that pairwise interspecific mutualism is more complicated than previously thought, implying that we may under-or overestimate the strength of mutualistic interactions when looking at only certain life-history stages. This study provides a conceptual basis for better understanding the mechanisms underlying ontogenetic shifts of mutualistic partners and more complex mutualistic networks mediated by the life-history stages of organisms and their stage-structured interactions

    Matrix-Embedded Osteocytes Regulate Mobilization of Hematopoietic Stem/Progenitor Cells

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    The bone marrow (BM) niche comprises multiple cell types that regulate hematopoietic stem/progenitor cell (HSPC) migration out of the niche and into the circulation. Here, we demonstrate that osteocytes, the major cellular component of mature bone, are regulators of HSPC egress. Granulocyte colony-stimulating factor (G-CSF), used clinically to mobilize HSPCs, induces changes in the morphology and gene expression of the osteocytic network that precedes changes in osteoblasts. This rapid response is likely under control of the sympathetic nervous system, since osteocytes express the β2-adrenergic receptor and surgical sympathectomy prevents it. Mice with targeted ablation of osteocytes or a disrupted osteocyte network have comparable numbers of HSPCs in the BM but fail to mobilize HSPCs in response to G-CSF. Taken together, these results indicate that the BM/bone niche interface is critically controlled from inside of the bone matrix and establish an important physiological role for skeletal tissues in hematopoietic function

    The Pilot Study for Health Check-Ups System at Elementary School in Cambodia

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    Background: In Cambodia, there is no national health check-ups system for the schoolchildren and the general population. This pilot study aimed to promote a school health check-ups system in collaboration with the government of Cambodia. Method: From 2016 to 2017, we conducted a survey in an elementary school in Siem Reap province, Cambodia. Two hundred and ninety-two students were eligible for data analysis. Physical examination, questionnaire and urinalysis were conducted using the Japanese school health check-ups model. Anthropometry was measured using the World Health Organization’s growth reference data for school-age children. Results: Among 292 schoolchildren, 88.7% were diagnosed as healthy. Based on the evaluation criteria of health examination in the study, two (0.7%) students with rale, one (0.3%) student with abnormal urinalysis, and another 27 students complaining of cardiopulmonary symptoms were recommended for further consultation at hospital. The prevalence of overweight (15.1%) was higher than that of underweight (8.6%). According to parents’ questionnaires responses, the coverage rate of the National Immunization Program varied from 41.8% to 79.8% depending on each particular vaccine. Conclusion: In this pilot study, we showed the prevalence of healthy among Cambodian schoolchildren and detected the students having possibility of health problem through this health check-ups and then recommended for further hospital visit. Based on the results, we assume that health check-ups system in elementary school as a whole Cambodia will be effective to assess the current health status in ordinary time and possibility of early detection of disease
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