Growing situation of afforested trees and damage to lower-story trees caused by felling in multi-storied forest management in Peninsular Malaysia

The growing condition of afforestation trees and damage to lower-story trees caused by felling and hauling of upper-story trees in a multi-storied forest in Peninsular Malaysia was surveyed. Seventy months have passed since the planting ofAcacia mangium upperstory trees, which have grown 233 m³/ha in volume. The growth ofShorea leprosula thirty-five months after planting of lower-story trees have reached 5.54 m in height. However, as the ratio of height to basal diameter exceeds 100:1, trees are tapering to a considerable degree. A backhoe was installed in order to fell the upper-story trees. From the results of logging, the damage ratio estimation of the lower-story trees was simulated by using the Monte Carlo method. The damage ratio differed considerably depending on planting patterns, height of upper-story trees and felling skills. The results of this survey proved that the felling and hauling of upper-story trees would be technically feasible in the future, except when one row upper-story trees and one row lower-story trees method were employed.     

The method for designing the profile of forest roads supported by genetic algorithm

This study examines a method for designing an optimum profile of a forest road in a short matter of time. In this method, a genetic algorithm (GA) searches for points where the gradient changes and dynamic programing (DP) designs the longitudinal slope. This method can be applied to the ground heights of an actual forest road. The evaluation function of the DP assesses the total expenditure. The inverse of this function is the fitness function. Crossover and mutation are operators of an evolution simulation of a GA. They are each repeated 20 times and 420 profiles are designed and assessed, all within about 10 min. A comparison of the profile designed by the GA with that of an actual forest road shows only one section where the formation level differed substantially. Overall, both profiles seem to show a high degree of correspondence. From this result, we believe that the profile designed by the GA is best, or the one of the best. A conventional method takes about 65 h to calculate all changing points of gradients. However, by using the GA, the calculation time was reduced to about 1/389 that of the coventional method, showing that the method which uses the GA through the profile design is very useful.     

Work environment of processor operators

Seven processor operations were investigated to examine the work environment of the processor operator. The invisible objects in the visual field of four processors were the jib, head, instrument for measuring logs, wiper, and cabin. The operator looked mostly at “the head of the processor” during delimbing, bucking and arranging; “the delimbed tree-length log for bucking” during delimbing and bucking; “the bucked log” during bucking and arranging; and “the sides of the road” during moving and skidding. From the frequency of fixation for each fixated object, the instrument for measuring logs and the head was found to require the most attention. The height of three processors’ steps for “mounting and alighting” were higher than the optimum value (58 cm), obtained from an anthropometric investigation of forest machine operators. The levers and pedals of four processors were arranged at suitable positions, according to JIS guidelines.     

Seasonal changes in oocyte size and maturity of the giant jellyfish, Nemopilema nomurai

To determine the reproductive season of the giant jellyfish Nemopilema nomurai, we investigated gonadal maturity in specimens collected from the East China Sea, Korea Strait, Wakasa Bay, and the Shonai Coast of Yamagata Prefecture. After the sex of the samples was determined, the long axis of at least 256 oocytes from each female was measured. In specimens collected from the coast of Japan in 2005 and in 2006, all gonads were sufficiently developed to determine sex. However, 18 of the 20 specimens from the East China Sea collected in July 2005 were immature, and sex could not be determined. The maximum and third quartile of oocyte length had a significant correlation with days elapsed from 30 June, but they were not related to bell diameter. Observations of gonad tissue sections of specimens collected in Wakasa Bay in 2006 confirmed that oocyte length was a good proxy for female maturity. Male maturity could also be determined. In conclusion, the sex of all of the small-sized medusae collected along the coast of Japan was determinable, and their gonads were at various stages of development up to fully mature. Therefore, the occurrence of small-sized jellyfish during the autumn in Wakasa Bay is not caused by recruitment of young population from the nearby coast.     

First record of wild ephyrae of the giant jellyfish Nemopilema nomurai

To understand the causes and to control harmful blooms of the giant Nomura??s jellyfish Nemopilema nomurai, it is essential to study the seed population (benthic polyps) and its environment. To locate the habitat of polyps, the first step is to find ephyrae shortly after detachment from polyps. We found five ephyrae of N. nomurai of 1?C2?mm diameter for the first time from plankton samples collected at two sites, one specimen in the northwestern East China Sea (32°12.3??N, 123°12??E) and the other four specimens in the Yellow Sea (34°05.8??N, 121°50.0??E), on 22 and 26 May 2011. From the developmental state and water temperature of ca. 16?°C at the sampling stations, the collected ephyrae were estimated to have detached from polyps in early May of the year. Considering the increase of water temperature which induces strobilation and the direction of transport in the northwestern East China Sea and in the Yellow Sea, the locality of the seed polyps of the present specimens is probably the sea-floor close to the Changjiang River mouth and along the coast of Jiangsu Province.     

Dietary docosahexaenoic acid can alter the surface expression of CD4 and CD8 on T cells in peripheral blood

The effect of dietary docosahexaenoic acid (DHA) on T cell states in peripheral blood was investigated. Weanling male C57Bl/6N mice were kept on one of three 10% fat diets containing various amounts of DHA and linoleic acid for 4 weeks. Changing the concentration of dietary DHA did not alter the proportion of T cells expressing CD4 or CD8. However, increasing the concentration of dietary DHA lowered the expression of CD4 and CD8 on the cell surface. The decreased expression of these surface molecules involved in T cell proliferation has serious implications in the role of DHA as an immunosuppressant.