Association between hand-grip strength and depressive symptoms: Locomotive Syndrome and Health Outcomes in Aizu Cohort Study (LOHAS).

First published online: February 21, 2015no study has examined the longitudinal association between hand-grip strength and mental health, such as depressive symptoms

対馬・龍良山の照葉樹林の研究 V.成熟林分における林冠ギャップとギャップ更新

Gaps are very important structure for the maintenance mechanism of tree populations, community organization or species diversity of forest communities. To evaluate gap structure and gap regeneration in well-preserved primary evergreen broad-leaved forests, this paper in the series of this study described actual states of canopy gaps and clarified gap regeneration of major tree species in oldgrowth evergreen broad-leaved forest stands, Tatera Forest Reserve, Tsushima, southwestern Japan. The results clarified the gap structure such as percentage gap area, gap density, gap size and characteristics of gapmakers etc. and the gap regeneration behaviors of major tree species in the stands

対馬・龍良山の照葉樹林の研究 VII. 原生林と二次林の組成と構造の比較解析

対馬・龍良山の照葉樹林研究の一環として、本研究では原生林と二次林の組成と構造を比較解析し、原生状態への復帰過程にある二次林の保護の重要性を指摘した｡1)原生林の林冠層では、シイノキ、イスノキ、ウラジロガシが優占していた｡シイノキは、ギャップ形成後、ギャップ内で定着した稚樹で更新するとともに、萌芽によっても更新していた｡一方、イスノキは、ギャップ形成前に定着した稚樹がギャップ形成後、ギャップ内で成長して更新する更新様式であった｡サカキは典型的な亜高木性樹種であった｡2)二次林の林冠層は、シイノキでほとんど優占されていた｡このシイノキの林冠木のほとんどが萌芽起源であった｡しかしながら、林内にはシイノキの稚樹や幼木が少なかった｡イスノキは林冠層にはわずかしかなかったが、稚樹・幼木として多数出現した｡サカキの稚樹・幼木は少なかった｡3)今後、人為撹乱がなければ、二次林の林冠層のシイノキは減少し、イスノキは増加することが予想され、この二次林は着実に原生状態へ復帰しつつあると判断された｡したがって、原生状態へ復帰させるために、この二次林を人為撹乱から保護することは重要な課題といえる｡In the Tatera Forest Reserve, tracts of secondary forests are contiguous to the primary forest. The secondary forest is young and regenerating after deforestation for production of charcoal. Our comparative study in the primary and secondary forests revealed that the canopy gap is present in the primary forest but absent in the secondary one, that Castanopsis cuspidata var. sieboldii is the dominant canopy tree species in both of the forests, and that Distylium racemosum, the second dominant in the canopy of the primary forest, is the major species having abundant regenerating saplings in the both forests. Those facts imply that the secondary forest will surely reach the same status as the primary forest and merge in the latter without difference in structure and composition, unless man disturbs or interferes the secondary forest tract for many years in the future. One of the conclusions in the present study emphasizes the importance of the secondary forest for the preservation of primeval fores

Land mobile satellite propagation measurements in Japan using ETS-V satellite

Propagation characteristics of land mobile satellite communications channels have been investigated actively in recent years. Information of propagation characteristics associated with multipath fading and shadowing is required to design commercial land mobile satellite communications systems, including protocol and error correction method. CRL (Communications Research Laboratory) has carried out propagation measurements using the Engineering Test Satellite-V (ETS-V) at L band (1.5 GHz) through main roads in Japan by a medium gain antenna with an autotracking capability. This paper presents the propagation statistics obtained in this campaign