Kenichi Tatsumi

Crop classification of upland fields using Random forest of time-series Landsat 7 ETM+ data

Application of Random forest approach for crop classification.The use of EVI obtained from time-series Landsat 7 ETM+ imagery as predictor variables.Effects of number of predictor variables, decision trees and training data on classification accuracy.Random forest as an appropriate method to classify the upland field crops within a homogeneous region. Crop classification of homogeneous landscapes and phenology is a common requirement to estimate land cover mapping, monitoring, and land use categories accurately. In recent missions, classification methods using medium or high spatial resolution data, which are multi-temporal with multiple frequencies, have become more attractive. A new mode of incorporating spatial and temporal dependence in a homogeneous region was tried using the Random Forest (RF) classifier for crop classification. A time-series of medium spatial resolution enhanced vegetation index (EVI) and its summary statistics obtained from Landsat 7 Enhanced Thematic Mapper Plus (Landsat 7 ETM+) were used to develop a new technique for crop type classification. Eight classes were studied: alfalfa, asparagus, avocado, cotton, grape, maize, mango, and tomato. Evaluation was based on several criteria: sensitivity to training dataset size, the number of variables, and mapping accuracy. Results showed that the training dataset size strongly affects the classifier accuracy, but if the training data increase, the rate of improvement decreases. The RF algorithm yielded overall accuracy of 81% and a Kappa statistic of 0.70, indicating high model performance. Additionally, the variable importance measures demonstrated that the mode and sum of EVI had extremely important variables for crop class separability. RF had computationally good performance. They can be enhanced by choosing an appropriate classifier for multiple statistics and time-series of Landsat imagery. It might be more economical to use no-cost imaging for crop classification using open-source software.

Blocking effect of sperm immobilizing antibodies on sperm penetration of human zonae pellucidae

To investigate the mechanism of the blocking effect of sperm immobilizing antibodies on human fertilization, an in vitro zona penetration test was carried out using media containing the IgG fraction extracted from sperm immobilizing antibody-negative or-positive serum. The sperm penetration rate of the test was 100% (6/6) when spermatozoa were treated with the IgG fraction derived from sperm immobilizing antibody-negative serum, whereas it was only 17% (1/6) when spermatozoa were treated with the IgG fraction derived from sperm immobilizing antibody-positive serum. Electron microscopic observation of the sperm immobilizing antibody-negative and-positive serum-treated spermatozoa showed that the number of acrosome-reacted spermatozoa was significantly greater in the sperm immobilizing antibody-negative serum than in the antibody-positive serum. Therefore, it appears that one of the blocking mechanisms of the spermatozoal penetration of the zona pellucida by sperm immobilizing antibodies may be due to inhibition of the acrosome reaction in the spermatozoa.

A New Therapeutic Antibody Removal Method Using Antigen Positive Red Cells: Application to M-Incompatible Pregnant Women

A study was made for the therapeutic removal of red cell antibodies using antigen positive red cells. With preliminary experiments in vitro, the criteria for the optimal absorption of anti‐M with O MM red cells were estimated to be the following: an incubation time of 10min, an incubation temperature of 0–4°C (in an ice‐water bath), and a red cell‐to‐plasma ratio of 1:2.5.

Effects of climate change on daily minimum and maximum temperatures and cloudiness in the Shikoku region: a statistical downscaling model approach

In this study, we present a detailed analysis of the effect of changes in cloudiness (CLD) between a future period (2071–2099) and the base period (1961–1990) on daily minimum temperature (TMIN) and maximum temperature (TMAX) in the same period for the Shikoku region, Japan. This analysis was performed using climate data obtained with the use of the Statistical DownScaling Model (SDSM). We calibrated the SDSM using the National Center for Environmental Prediction (NCEP) reanalysis dataset for the SDSM input and daily time series of temperature and CLD from 10 surface data points (SDP) in Shikoku. Subsequently, we validated the SDSM outputs, specifically, TMIN, TMAX, and CLD, obtained with the use of the NCEP reanalysis dataset and general circulation model (GCM) data against the SDP. The GCM data used in the validation procedure were those from the Hadley Centre Coupled Model, version 3 (HadCM3) for the Special Report on Emission Scenarios (SRES) A2 and B2 scenarios and from the third generation Coupled Global Climate Model (CGCM3) for the SRES A2 and A1B scenarios. Finally, the validated SDSM was run to study the effect of future changes in CLD on TMIN and TMAX. Our analysis showed that (1) the negative linear fit between changes in TMAX and those in CLD was statistically significant in winter while the relationship between the two changes was not evident in summer, (2) the dependency of future changes in TMAX and TMIN on future changes in CLD were more evident in winter than in other seasons with the present SDSM, (3) the diurnal temperature range (DTR) decreased in the southern part of Shikoku in summer in all the SDSM projections while DTR increased in the northern part of Shikoku in the same season in these projections, (4) the dependencies of changes in DTR on changes in CLD were unclear in summer and winter. Results of the SDSM simulations performed for climate change scenarios such as those from this study contribute to local-scale agricultural and hydrological simulations and development of agricultural and hydrological models.

Effects of the supernatants of mixed lymphocyte cultures and decidual cell line cultures on mouse embryo development in vitro.

The effects of supernatants of human mixed lymphocyte cultures (MLC), with or without human decidual cell line culture extract (decidual factor; DCF), on F1-hybrid mouse embryo development in vitro from the two-cell stage were investigated. The development of mouse embryos from the two-cell stage through the expanded blastocyst stage was facilitated significantly by the addition of supernatants of not only MLC, but also MLC supplemented with DCF (MLCDCF) to the culture medium. Moreover, the supernatant of MLCDCF accelerated the attachment of the hatched blastocyst to the culture dish substratum and the outgrowth of trophoblasts in vitro. The findings indicate that the supernatant of MLCDCF facilitates the in vitro activity of mouse embryos for implantation and that the maternal immune response, along with the decidual tissue, contributes to the implantation processes.