The critical stress in various stress levels of bending member on fire exposure for mechanical graded lumber

This study focused on the relationship between stress level and the fire resistance of structural lumber. The 210 samples were prepared from 15-year-old trees of Acacia mangium from the Forest Estate Plantation, Indonesia. Specimens were 20 ® × 20 (T) × 500mm (L) and were air-dried. Sixty samples were tested under four-point bending stress to obtain the modulus of elasticity (MOE) and the modulus of rupture (MOR) for classifying the stress grades of the remaining 150 samples. The tests were performed using a four-point load bending position at various stress level while the specimens were exposed to fire along the shear-free region. Time to failure was affected by the stress levels in an exponential trend. Despite changes in stress level, charring rate, and time to failure, the critical stress of a member from the same species was similar. The fire performance under applied load could be predicted by using simplified fire-testing methods. The developed testing apparatus is valid for evaluating the small-scale fire resistant behavior of structural lumber in bending.     

Bone morphological analyses in Spontaneously Diabetic Torii (SDT) fatty rats

The Spontaneously Diabetic Torii (SDT) fatty rat, a model for obese type 2 diabetes, shows bone quantitative abnormalities, namely low bone mineral density (BMD). The objective of this study was to evaluate bone morphological changes, in particular identifying the bone qualitative abnormalities, in the SDT fatty rat. Male SDT fatty rats showed increases in total trabecular area and trabecular number and decreases in trabecular thickness in cancellous bones of the proximal tibia, indicating trabecular miniaturization. The SDT fatty rat is useful for investigation of pathophysiological changes in bone quality in diabetic osteoporosis.     

Stocking effectiveness of hatchery-released kuruma prawns estimated by two-stage sampling of commercial catch in Ariake Sound, Japan

ABSTRACT:    To evaluate the stocking effectiveness of the kuruma prawn Penaeus japonicus , a two-stage sampling survey of Gensiki bottom-drift-netters was carried out in Ariake Sound, Saga Prefecture, Japan. A total of 471 000 hatchery-produced juveniles, marked by cutting off the right uropods, was released. Thirty-three fishing days were randomly drawn from four boats, which were selected from the 80 boats operating in the fishery. All prawns caught on the selected days were examined, and the hatchery-produced individuals were identified by their regenerated uropods. A telephone survey of all boats was also conducted, to determine the number of fishing days. A total of 286 marked prawns were caught on the survey days for the Saga area in Ariake Sound, from the last half of July to the first half of September 2002. The recapture rate and standard error were estimated at 0.76 ± 0.52%. Economic efficiency was estimated at 0.28 ± 0.02. Strategies for sampling schemes and stock recovery are also discussed.     

防火林带营造木荷火力楠混交林生长效果分析

对马尾松低产林改造,营造防火林带木荷火力楠生长效果进行了调查,发现林木生长良好。结果显示：经过14a的培育,其林木生长不同,木荷火力楠混交林的林分生长量,比木荷、火力楠纯林的林分生长量更具优势,平均树高、胸径、树冠、枝下高、郁闭度、单株材积、蓄积量,分别比木荷、火力楠纯林林分平均树高大13.54%、8.55%,胸径粗18.39%、14.21%,树冠大8.24%、22.26%,枝下高8.75%、17.67%,郁闭度大2.13%、3.23%,单株材积大45.43%、41.18%,蓄积量大54.95%、37.54%。土壤肥力N、P、K分别提高0.9%、1.92%、1.79%,1.80%、6.00%、3.64%。木荷火力楠混交林能涵养水源、保持水土,有效控制林火蔓延,可减少森林火灾和灾后损失。     

Responding to climate change and expectations for research

Paddy and Water Environment -     

The conservation and fishery benefits of protecting large pike (Esox lucius L.) by harvest regulations in recreational fishing

Traditional fisheries management theory supports aggressive exploitation of old and large fish to maximize a stock’s biomass production and yield. Here we present an age-structured fish population model with multidimensional density-dependence to test the hypotheses that protection of large, fecund individuals is beneficial for the population and selected fisheries variables and that effects of maternal size on early survival rate change the resilience and fisheries productivity of a pike population (Esox lucius L.) exploited by recreational angling. We find that, compared to the traditional regulatory approach of management by small minimum-length limits (so that culling of large fish is encouraged), preservation of large and old individuals through harvestable-slot length limits promises considerable benefits for fisheries quality, without compromising the long-term conservation of the population. We also find that ignoring maternal effects on early survival of offspring might overestimate the equilibrium spawning stock abundance by up to 17% and the predicted harvest by up to 11%, potentially putting pike populations at risk from overharvest if size-dependent maternal effects are ignored in fisheries models. If the findings from our simulation study hold for empirical systems, they suggest altered harvest regulations in many of consumptive pike recreational fisheries are needed to protect large individuals to a greater extent that currently pursued.     

Supplementation of Citric Acid and Amino Acid Chelated Trace Elements in Low‐Fish Meal Diet for Rainbow Trout Affect Growth and Phosphorus Utilization

This study was conducted to evaluate the effect of citric acid (CA) and amino acid chelated trace elements (AA) on the growth, phosphorus (P) utilization efficiency and loading in rainbow trout fed a diet formulated with a low‐fish meal (FM) concentration. A low‐FM basal diet with or without monocalcium phosphate supplementation served as positive and negative control correspondingly. Dietary treatments consisted of the basal diet supplemented either with 1% CA, AA (equivalent to 40 Zn, 20 Mn, and 4 Cu mg/Kg of diet instead of inorganic trace element mix) or a combination of both. Duplicate groups of 35 fish (13.2 g) were fed until apparent satiation during 12 wk. Group of fish fed diets supplemented with 1% CA or AA had a final growth and feed utilization similar to that observed in fish fed the positive control diet (P > 0.05). P absorption was increased with the addition of CA or AA. P retention efficiency rates for these diets were higher in comparison with the rest of the treatments consequently showing the lowest P loading values (P < 0.05). The results indicate that addition of 1% CA or AA, to a low‐FM diet without inorganic P supplementation enhanced fish growth, P retention, and decreased P load to the environment.