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Volume 40 (2003)
- Issue 4 Pages 183-
- Issue 2 Pages 83-
- Issue 1 Pages 3-
Volume 40, Issue 4
Displaying 1-5 of 5 articles from this issue
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Original Article
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Akio Tsuchiya, Hiroshi SakugawaArticle type: Original Article
2003 Volume 40 Issue 4 Pages 183-195
Published: 2003
Released on J-STAGE: February 16, 2004
JOURNAL FREE ACCESSIn this study, the effects upon medium and small-sized tree individuals after the dieback of red pine were investigated in Saijo Basin, Hiroshima, in terms of forest structure, tree-ring chronologies, energy balance, vessel parameters of stem cross sections, and the biomass of dead pines. It was found from forest structure that the canopy layer has been greatly reduced due to the withering of red pines, and the highest class has shifted down to medium-sized trees such as Cryptomeria japonica, Quercus serrata, Acanthopanax sciadophylloides, and Ilex rotunda. Also, it was found from tree-ring chronologies that such medium-sized individuals were increasing their thickening growth. This coincides with the fact that downward short-wave radiation can now reach the middle layers so that they are guaranteed the radiation necessary for phtosynthesis, and the percentage of vessel area has risen to support the increasing growth. Such changes began in the second half of the 1970s. However, understory individuals such as Eurya japonica, Lyonia ovalifolia, and Ilex crenata have been left lightly stressed. Also, the dead biomass of red pines was estimated to be 2,204 to 10,870 t/km2. The dieback accelerated the growth of medium-sized trees but it did not encourage the growth of small-sized trees near the forest floor. Consequently, the two layers, which had remained together in the forest before the dieback, have increased the distances between them.
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Eiji Tokunaga, Kana Mima, Nobuko Hashiguchi, Masahide Kaji, Yutaka Toc ...Article type: Original Article
2003 Volume 40 Issue 4 Pages 197-202
Published: 2003
Released on J-STAGE: February 16, 2004
JOURNAL FREE ACCESSJet airplanes enable people to travel more than 10000km in 10hours, but the prolonged sitting involved sometimes causes “Economy-class syndrome”. The air pressure in passenger aircraft is comparable to that at 2000m above sea-level and relative humidity (RH) is less than 20%. There is no study on the effects of hypobaric hypoxia and low humidity on physiological responses. Nine healthy male students sat quietly for 2hours in a chair under the following four conditions: A, sea-level air pressure, 60%RH; B, sea-level air pressure, 20%RH; C, air pressure at 2000m above sea-level, 60%RH; D, air pressure at 2000m above sea-level, 20%RH. Blood samples were collected from a vein of the foot, and the circumference of the lower leg and body weight were measured before and after 2 hours of sitting. The circumference of the lower leg increased significantly under all conditions. The increases were more prominent in hypoxia. Albumin and total protein concentration increased significantly under the B, C and D conditions. Red blood cell count increased significantly under the B, D conditions. Hematocrit percentage increased significantly only under the D conditions. These findings suggest that prolonged sitting in low air pressure and low humidity environments, similar to the conditions on an airplane-trip, can increase the stasis and hemoconcentration.
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Akio Tsuchiya, Takahisa TohyamaArticle type: Original Article
2003 Volume 40 Issue 4 Pages 203-217
Published: 2003
Released on J-STAGE: February 16, 2004
JOURNAL FREE ACCESSFrom November 2001 to May 2002, except for March, radiation balance was measured above the water surface of Minaga Reservoir, and vertical profiles of temperature and humidity were measured using captive and hot-air balloons in Saijo Basin, Hiroshima Prefecture, western Honshu. In November, heat storage into water caused by daytime net radiation was high, and nighttime temperatures reached the dew point due to radiative cooling. As a result, radiation fog hovered over 100m above the ground surface. In winter, from December to February, the thickness of radiation fog was limited because daytime net radiation did not reach sufficiently high levels although nighttime cooling was strong. The energy input was plentiful from April to May, but fog did not occur because temperature decrease was weak. It was found through measurements that the heat storage change of water regulated a negative net radiation during nighttime, and the heat release and vapor supply from water surface, as well as temperature decrease due to radiative cooling caused by non-water mass, generated fog in the basin. When estimating the amount of condensation at nighttime from the total area of reservoirs in the basin (4.1km2), the specific height of fog, and the decrease of absolute humidity from sunset to daybreak, it was found to total 844.6t in November, 114.8t in December, and 49.2t in February.
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Review
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Jun SatoArticle type: Introduction
2003 Volume 40 Issue 4 Pages 219-224
Published: 2003
Released on J-STAGE: February 16, 2004
JOURNAL FREE ACCESSIt has been long observed that weather change is associated with increased complaints of pain, although the exact mechanism for this phenomenon remains unclear. To clarify this issue, we have used a climate-controlled room to examine the effects of exposure to low barometric pressure (27hPa lower than the natural atmospheric pressure) and low ambient temperature (7 °C decrease from 22°C) on the pain-related behaviors of rats rendered monoarthritic or neuropathic. Our results show that low-pressure and low-temperature exposures intensify abnormalities in the pain-related behaviors of these rats. Additionally, sympathetic nervous activity makes an important contribution to the low-pressure effect, while it does not appear to be important for the low-temperature effect. Our recent experiments also demonstrated that inner ear destruction inhibited the low-pressure effect on the neuropathic rats, suggesting a specific organ which senses changes in barometric pressure is located in the inner ear.
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Satoru TakadaArticle type: Introduction
2003 Volume 40 Issue 4 Pages 225-234
Published: 2003
Released on J-STAGE: February 16, 2004
JOURNAL FREE ACCESSVarious models on human thermal system have been proposed. The characteristics of each model are summarized in this paper. It is shown that all the models essentially consist of heat balance equations for human body represented as several nodes and that the temperature regulation responses (blood flow, sweating, shivering) are described by the functions of deviation of skin and core temperatures from respective reference temperature. An example of comparison between the calculated results by a model of human thermal system and the experimental results are shown, and the problems in predicting the temperature regulation response by models are pointed out to describe the outlook for the future work and the application of the models.
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