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21.
Carayonovus insignis n. gen., n. sp., a remarkable new genus and species of Heteroptera, is described from Reunion Island. It is tentatively placed in the family Anthocoridae (Cimicoidea), but because of its remarkable sexual dimorphism and possession of characters not normally associated with this family or even with Cimicoidea, the genus is discussed in terms of the validity or otherwise of including it in these taxa. Its habitat preference is also examined.  相似文献   
22.
A study was carried out to determine Fusarium wilt distribution in Bambara nut farmers’ fields and its management using farm yard manure (FYM). Four villages in Busia County were purposively sampled for the study. The data generated were subjected to analysis of variance and treatment means separated by least significant difference test. Fusarium wilt incidence in the fields ranged from 14.63 to 43.56%. In the greenhouse, FYM reduced the disease incidence by 10.2% and severity by 9.5% on the black landrace and 1.9 and 12.8%, respectively, on the red landrace. In the field, FYM reduced disease incidence by 9.1% and severity by 6.9% on the black landrace and 10.4 and 10.4%, respectively, on the red landrace. Farm yard manure had the lowest area under disease progress curve irrespective of the landrace. The study confirmed the presence of the pathogen in the fields and the ability to manage the disease using FYM.  相似文献   
23.
The phylogeny of the Vitrinidae is reconstructed in a cladistic analysis based on characters of the genitalia, the copulation behaviour and the radula. The genera with an atrial stimulator turned out to be the earliest branches of the Vitrinidae, whereas the genera with a glandula amatoria form a monophyletic, taxonomically apomorphic group. The differences between the proposed phylogeny and previous hypotheses are discussed. The ancestral areas of the Vitrinidae and its sister group, the limacoid slugs Boettgerillidae–Limacidae–Agriolimacidae, are estimated using weighted ancestral area analysis. The Vitrinidae and the limacoid slugs might have originated by a vicariance event between Central Europe and the Near East. © 2002 The Linnean Society of London. Zoological Journal of the Linnean Society , 2002, 134 , 347–358.  相似文献   
24.
The gill surface area of 0-group, post-metamorphic Pleuronectes flesus L. was examined using digital image analysis software and expressed in relation to body mass according to the equation log Y=loga+c logW ( a =239·02; c =0·723). The components that constitute gill area, total filament length, interlamellar space and unilateral lamellar area were measured. The measurement of the length of every filament on all eight arches showed that commonly used methods of calculation can lead to an under-estimation of up to 24% of total filament length. Direct measurements of unilateral lamellar area with digital image analysis showed that previously reported gill area data for the same species was over-estimated by as much as 58%. In addition, in this species the neglect of gill pouch asymmetry after metamorphosis, can bring about a 14% over-estimation of total gill area.  相似文献   
25.
The current guideline for exposure to radiofrequency radiation (RFR) was developed through assessment of the biological effects data collected primarily from the rat. The consensus that a lack of hazardous biological effects occurred below a whole-body-averaged specific absorption rate (SAR) of 4.0 W/kg led to the proposition of a 0.4 W/kg guideline with a built-in safety factor of 10. This paper demonstrates that if the RFR absorption rate in the rat had been normalized with respect to total body surface area rather than body mass, the exposure guideline would be 2.3 W/m2, which translates to an SAR of approximately 0.06 W/kg for an adult human. It is further shown that a given RFR absorption rate, normalized as a fraction of a species' heat loss per unit of surface area, is independent of body mass over a range of 0.03-100 kg; however, a normalization of the RFR absorption rate to heat loss per unit of body mass is highly dependent on the species' mass. Normalizing the rate of RFR absorption to the surface area of the rat indicates that the current RFR exposure guideline of 0.4 W/kg may be too high.  相似文献   
26.
27.
The fate of15N labeled nitrogen applied to mature citrus trees   总被引:1,自引:0,他引:1  
Summary The efficiency and balance of nitrogen from one year's application was studied in a long-term fertigation experiment. Enriched nitrogen fertilizer, K15NO3, was applied to a 22-year-old Shamouti orange tree with a history of high N applications (N3) and to an N-starved tree (N1). The distribution of N in the different parts of the trees and in the soil was determined after the experimental trees were excavated. Similar total recovery of the labeled fertilizer N was found in the trees and soil in both treatments (N1−61.7% N3−56%). However, the distribution between tree and soil was different. The amount of recovered residual fertilizer in the soil was much larger in the N3 treatment than in N1. The highest percentage of fertilizer N was found in the new organs,i.e. fruits, twigs and leaves. The roots and branches took up only 6–14% from the labeled fertilizer. Only 20.9% of the leaf N and 23.4% of the fruit N in the N3 tree originated in the labeled fertilizer, indicating translocation of N from older parts of the tree to new growth. Evidence was found of storage of N in the wooded branches, while the roots contained a surprisingly small part of labeled fertilizer. Contribution 1599E.  相似文献   
28.
This study is based on a sample of 9,134 children ranging in age from 2 to 17 years from which the excessively lean and fat children by skinfold thickness were excluded. This sample was derived from the combined data sets of the first and second National Health and Nutrition Examination Surveys (NHANES I and II) of 1971-1974 and 1976-1980. Means and percentiles of upper arm muscle area were calculated for 3 cm increments in stature from 84 to 184 cm for boys and from 84 to 176 cm for girls. Based on means, Z-score units, and percentile ranges of upper arm muscle area by stature, five operational categories of nutritional status have been established. It is recommended that these standards and this classification system be used to supplement current standards of weight for age and weight for height in order to obtain a more complete assessment of body composition and nutritional status.  相似文献   
29.
电刺激杏仁复合体能诱发心律失常。心律失常的类型为心动过缓伴室性或结性期外收缩。刺激杏仁复合体不同亚核均能诱发心律失常,不同类型的心律失常在核内具有相应的代表点。心律失常发作与杏仁局部区域诱发的爆发性后放电有关。推测杏仁复合体内神经元过度激活可能通过杏仁-迷走神经运动背核及杏仁-下丘脑外侧区等通路下行,使心率减慢、房室传导阻滞而导致心律失常。  相似文献   
30.
Birch ( Betula pendula Roth.) was investigated under steady-state nutrition and growth at different incident photon flux densities (PFD) and different relative addition rates of nitrogen. PFD had a strong influence on the relative growth rate at optimum nutrition and on the nitrogen productivity (growth rate per unit of nitrogen) but little effect on the formal relationships between nitrogen and growth, i.e. PFD and nitrogen nutrition are orthogonal growth factors. At a given suboptimum nitrogen (the same distance from optimum), increased PFD increased the relative growth rate and, therefore, the relative uptake rate and the required relative addition rate in accordance with the theoretical equality between these three parameters at steady-state nutrition. Correspondingly, at a given suboptimum relative addition rate, increased PFD decreased nitrogen status (larger distance from optimum) at an unchanged relative growth rate. Nutrient uptake rate, dry matter content, and partitioning of biomass and nutrients are strongly influenced by nitrogen status. PFD influences these characteristics, but only to an extent corresponding to its effect on the nitrogen status. The influence of PDF on the relative growth rate at optimum and on nitrogen productivity is well described by hyperbolic relationships, similar to reported PFD/photosynthesis relationships. These expressions for plant growth as well as the productivities of leaf area and quantum appear to be valuable characteristics of plant responses to light and nutrition. Although the calculated PFD/growth relationships indicate saturation at high values of PFD, a more realistic estimate of PFD at which saturation occurs is about 30 mol m−2 day−1, where the highest relative growth rate and nitrogen productivity were experimentally determined. No significant effect was observed because of day length differences between the present and previous experiments.  相似文献   
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