Bayesian mapping of neural tube defects prevalence in Heshun County, Shanxi Province, China during 1998～2001

Objective: To estimate the prevalence rates of neural tube defects (NTDs) in Heshun County, Shanxi Province, China by Bayesian smoothing technique. Methods: A total of 80 infants in the study area who were diagnosed with NTDs were analyzed. Two mapping techniques were then used. Firstly, the GIS software ArcGIS was used to map the crude prevalence rates. Secondly, the data were smoothed by the method of empirical Bayes estimation. Results: The classical statistical approach produced an extremely dishomogeneous map, while the Bayesian map was much smoother and more interpretable. The maps produced by the Bayesian technique indicate the tendency of villages in the southeastern region to produce higher prevalence or risk values. Conclusions: The Bayesian smoothing technique addresses the issue of heterogeneity in the population at risk and it is therefore recommended for use in explorative mapping of birth defects. This approach provides procedures to identify spatial health risk levels and assists in generating hypothesis that will be investigated in further detail.

Incidence and Development of Powdery Mildew （Blumeria graminis f.sp. tritici） in the Czech Republic in the Years 1999-2010 and Race Spectrum of This Population

Powdery mildew （Blumeria graminis f.sp. tritici） is one of the most important leaf diseases of wheat on the worldwide. Evolutionary potential of a pathogen population is reflected in its population genetic structure. Severity of powdery mildew in twelve years of small-plot experiments was in individual years different. Incidence of powdery mildew was followed in 1999-2010 and powdery mildew development was studied in 2003 and 2004 in the Crop Research Institute （CRI）. These experiments were made on the cultivar Kanzler, susceptible cultivar to powdery mildew. Disease severity was made as a percentage of typical symptoms of the disease. Structure of powdery mildew population was probed in 2009 and 2010 in CRI and in the locality Humpolec. The highest was in 2004 and the lowest in 2003. Development of the disease in two extreme years depended on progress of weather factors mainly to average daily temperature and photosynthetic active radiation. In the year 2009 was higher disease severity in CRI than in the CRI station in Humpolec but in 2010 vice versa higher disease severity was in Humpolec. Observation showed that in small distances of two localities can be differences in composition of powdery mildew population. Higher virulence in CRI was to the gene of specific resistance Pml whereas in Humpolec to the gene Pm 17. In the year 2010 in CRI was the highest virulence to the gene Pm 1 whereas in Humpolec the highest virulence was to the genes Pm3fand Pm4a. Differences of powdery mildew were in 12 years of observation were very distinct and showed difference in structure of powdery mildew population in near localities.

A New Strain of Entomopathogenic Bacillus of the Tea Pest, Eterusia magnifica （Butl.） （Zyganiidae： Lepidoptera） from Darjeeling Foothill Region of India

An entomopathogenic strain of Bacillus sp. was isolated from diseased red slug caterpillars of the leaf-feediug pest of tea, Eterusia magnifica, from the Darjeeling foothill region. Analysis of the bacterimn based on polyphasic approach such as growth phase, biochemical tests, whole body＂ protein, crystal protein profiles along with bioassay （i.e. LC50 and LT50 values） established it as a different strain but close to Bacillus thuringiensis kurstaki （Btk）, the commercial microbial pesticides of lepidopterans. Among biochemical parameters differences were noted between the new strain and Btk in ONPG, lysine decarboxylase, omithin decarboxylase, urease, nitrate reduction, V-P and glucose utilization tests. PAGE analysis of the whole body protein for the new strain recorded a 34 kDa band which was absent in Btk （used as reference）. Crystal protein profile of the newly isolated bacterial strain showed 53 and 49 kDa bands whereas in Btk only 52 kDa band was evident. Although the LC50 values of the new strain and Btk were close, their LT50 values were much different, the new strain showing a lower value than Btk. In light of the above differences and in absence of any report of entomopathogenic bacterial strain of E. magnifica, the isolated strain of Bacillus appeared to be new to science and hence was designated as RS01. The new strain opens up the possibility of its futttre use as microbial pesticide after standardizing its formulation and checking its safety aspects.

Effect of high negative incidence on the performance of a centrifugal compressor stage with conventional vaned diffusers

Three vaned diffusers, designed to have high negative incidence (-8°) at the design operating point, are studied experimentally. The overall performance (efficiency and pressure ratio) are measured at three rotational speeds, and flow angles before and after the diffuser are measured at the design rotational speed and with three mass flow rates. The results are compared to corresponding results of the original vaneless diffuser design. Attention is paid to the performance at lower mass flows than the design mass flow. The results show that it is possible to improve the performance at mass flows lower than the design mass flow with a vaned diffuser designed with high negative incidence. However, with the vaned diffusers, the compressor still stalls at higher mass flow rates than with the vaneless one. The flow angle distributions after the diffuser are more uniform with the vaned diffusers.

Effect of Winglet Geometry Arrangement and Incidence on Tip Clearance Control in a Compressor Cascade

An experimental study is conducted to investigate the influences of blade tip winglet on the flow field of a compressor cascade. The tests are performed in a low speed linear cascade with stationary endwall, with three blade tip configurations, including the baseline tip, the suction-side winglet tip and the pressure-side winglet tip. The fiowfield downstream of the cascade is measured using five-hole probe, from which the three-dimensional velocity field, vorticity field and pressure field are obtained. Static pressure measurements are made on the endwall above the blade row using pressure taps embedded in the plywood endwall. All measurements are made at both design and off-design conditions for tip clearance level of about 2 percent of the blade chord. The results revealed the incidence variation significantly affects the secondary flow and the associated loss field downstream of the cascade, where the tip leakage vortex and passage vortex exist as the major contributors on the field. The winglet geometry arrangements can change the trajectory of the tip leakage vortex. The suction-side winglet tip blade provides a lower overall total pressure loss coefficient when compared to the baseline tip blade and pressure-side winglet tip blade at all incidence angles.