利用内部信息的农用自动引导行走车的研究(第3报)——农业环境内位置检测系统

采用内部传感器（压电式陀螺仪角速度计和雷达式速度计）来检测行走车的角速度和速度，通过对检测量的积分可分别得到方向角和移动距离，并可由位置计算模型获得行走车的方位。考虑到农业环境内车辆的纵摇和横摇的影响，使用３个角速度计构成相互垂直的直角坐标系，依此对角速度进行修正。该位置检测系统获得了较好的检测精度。     

Measurement of the maximum amount of water-extractable phosphorus in animal manure compost by continuous and sequential water extraction

Measuring the phosphorus (P) solubility in animal manure compost (AMC) is important to estimate both the risk of P loss from agricultural land and the P availability for crops in agriculture that use AMC as fertilizer. Water-extractable phosphorus (WEP) has most often been used to estimate P solubility in AMC. A single water extraction with a high ratio of compost to water is usually used to determine WEP, but in many cases, this may not evaluate the maximum WEP. In this study, we extracted the P included in AMC by using a continuous extraction method with a large amount of water, and tested this approach for 16 AMCs: four cattle manure composts, five swine manure composts, five layer (chicken) manure composts, and two broiler (chicken) litter composts. The P dissolution patterns were fitted to kinetic models, and the maximum WEP (WEP_max) was determined by the coefficient of the non-linear regression equation. The WEP_max values corresponded to the sum of H₂O- and sodium bicarbonate (NaHCO₃)-extractable P measured using the modified Hedley sequential extraction method. The result also suggests that the maximum amount of WEP from AMC can be estimated rapidly using a sequential extraction (the Hedley method) that has been widely used to characterize P in manure or AMC. The maximum water-extractable magnesium (Mg) (WEMg_max) was significantly positively correlated with WEP_max (r = 0.854, P < 0.01). This suggests that WEP_max in the AMCs is affected by water-soluble magnesium compounds.     

A weeding-duration model for Abies sachalinensis plantations in Hokkaido, northern Japan

I developed a weeding-duration model for Sakhalin fir (Abies sachalinensis (Fr. Schmidt) Masters) plantations that employs a generalized linear model. The number of years following planting that weeding is necessary is the response variable, and elevation, slope steepness, maximum snow depth, annual precipitation, geology, soil, site index, slope aspect, and vegetation type are explanatory variables. Among the explanatory variables, geology, soil, slope aspect, and vegetation type are categorical data. A Poisson distribution is assumed for the response variable, with a log-link function. Elevation, slope steepness, maximum snow depth, annual precipitation, site index, and vegetation type had a significant effect on weeding duration. Among the eight models with the smallest Akaike information criterion (AIC), I chose the model with no multicollinearity among the explanatory variables. The weeding-duration model includes site index, maximum snow depth, slope steepness (angle) and vegetation type as explanatory variables; elevation and annual precipitation were not included in the selected model because of multicol- linearity with maximum snow depth. This model is useful for cost-benefit analyses of afforestation or reforestation with Abies sachalinensis.     

Dynamic responses of nailed plywood-timber joints under a band-limited white-noise wave

In this study, dynamic tests of nailed plywood-timber joints are conducted under a band-limited white-noise wave using a uniaxial hydraulic shaking table. The principal results are as follows: dynamic responses of nailed plywood-timber joints under a band-limited white-noise wave are reasonably related to the static load-slip relationships and the dynamic responses under harmonic waves of them. When nailed plywood-timber joints are shaken under a composite wave of wide frequency range, they resonate transitionally with one of the frequency components one after another decreasing their equivalent resonant frequencies along their static load-slip curves. Nailed plywood-timber joints are in danger of ultimate failures even though the input maximum accelerations do not exceed their damage limits, if they are shaken for long times with or without intermittences. In this case, nailed plywood-timber joints are prone to fail in low-cyclic bending fatigue failure of nails. Nailed plywood-timber joints, on the other hand, are prone to fail in typical static failure modes when they are shaken under strong input maximum accelerations equivalent to their ultimate limits.     

Vitrification procedure decreases inositol 1,4,5‐trisphophate receptor expression,resulting in low fertility of pig oocytes

Although cryopreservation of mammalian oocytes is an important technology, it is well known that unfertilized oocytes, especially in pigs, are highly sensitive to low temperature and that cryopreserved oocytes show low fertility and developmental ability. The aim of the present study was to clarify why porcine in vitro matured (IVM) oocytes at the metaphase II (MII) stage showed low fertility and developmental ability after vitrification. In vitro matured cumulus oocyte complexes (COCs) were vitrified with Cryotop and then evaluated for fertility through in vitro fertilization (IVF). Although sperm‐penetrated oocytes were observed to some extent (30–40%), the rate of pronuclear formation was low (9%) and none of them progressed to the two‐cell stage. The results suggest that activation ability of cryopreserved oocytes was decreased by vitrification. We examined the localization and expression level of the type 1 inositol 1,4,5 trisphosphate receptor (IP₃R1), the channel responsible for Ca²⁺ release during IVF in porcine oocytes. Localization of IP₃R1 close to the plasma membrane and total expression level of IP₃R1 protein were both decreased by vitrification. In conclusion, our present study indicates that vitrified‐warmed porcine COCs showed a high survival rate but low fertility after IVF. This low fertility seems to be due to the decrease in IP₃R1 by the vitrification procedure.     

Advances in table grape breeding in Japan

In Japan, few grape cultivars related to Vitis vinifera existed 200 years ago, on account of Japan’s high rainfall. Many V. labruscana and vinifera cultivars were introduced to Japan in the 19th century. Labruscana was grown instead of vinifera, mainly because of severe disease problems and a high incidence of berry cracking. Grape breeding for table use started in the 20th century, with the goal of combining the berry quality of vinifera with the ease of cultivation of labruscana. By 1945, three strategies were used: 1) crossing among introduced diploid vinifera and vinifera-related cultivars of Japanese origin, 2) interspecific crossing in tetraploid cultivars, and 3) interspecific crossing in diploid cultivars, resulting in ‘Neo Muscat’, ‘Kyoho’, and ‘Muscat Bailey A’. Later, tetraploid interspecific crossing over generations developed many ‘Kyoho’-related cultivars, including ‘Pione’, many of which have large berries, intermediate flesh texture between the two species, a labruscan or neutral flavor, and moderate disease resistance. Interspecific diploid crossing over generations developed ‘Shine Muscat’ in 2006, with large berries, crispy flesh, a muscat flavor, no cracking, seedless fruit by gibberellin application, and moderate resistance to downy mildew and ripe rot.     

Glucosinolate metabolism,functionality and breeding for the improvement of Brassicaceae vegetables

Unique secondary metabolites, glucosinolates (S-glucopyranosyl thiohydroximates), are naturally occurring S-linked glucosides found mainly in Brassicaceae plants. They are enzymatically hydrolyzed to produce sulfate ions, D-glucose, and characteristic degradation products such as isothiocyanates. The functions of glucosinolates in the plants remain unclear, but isothiocyanates possessing a pungent or irritating taste and odor might be associated with plant defense from microbes. Isothiocyanates have been studied extensively in experimental in vitro and in vivo carcinogenesis models for their cancer chemopreventive properties. The beneficial isothiocyanates, glucosinolates that are functional for supporting human health, have received attention from many scientists studying plant breeding, plant physiology, plant genetics, and food functionality. This review presents a summary of recent topics related with glucosinolates in the Brassica family, along with a summary of the chemicals, metabolism, and genes of glucosinolates in Brassicaceae. The bioavailabilities of isothiocyanates from certain functional glucosinolates and the importance of breeding will be described with emphasis on glucosinolates.     

Sarcoptes scabiei var. canis refractory to ivermectin treatment in two dogs

A 10-year-old castrated male Shih Tzu presented with severe generalized pruritus. Skin scrapings revealed the presence of Sarcoptes scabiei var. canis. A Yorkshire terrier in the same household simultaneously developed pruritus due to scabies. Both dogs were treated with 300 μg/kg ivermectin, at first orally and then subcutaneously at 14 day intervals. However, live mites were still found on day 35, and the skin condition deteriorated in both dogs. These findings suggested that the S. scabiei in these dogs was clinically refractory to ivermectin. The pruritus in both dogs rapidly and completely disappeared following topical fipronil administration. This appears to be the first report of canine scabies refractory to ivermectin treatment.