桂西壮族手皮纹的分析

本文对广西西部500例健康壮族大、中学生的手皮纹进行了观察分析,计算出各型指纹频率、指纹脊线总数、指纹频度指数、atd角度、a-b脊线数、τ距比、主线横向指数、皮纹花样出现率、掌褶纹出现率共九项基本参数,并将这些数值与汉族作了比较,桂西壮族的手纹与汉族既有相似之处,又有本民族的特点。     

Predator driven changes in community structure

Summary The zooplankton community of a small pond changed markedly with temporal variation in predation pressure. Long term changes in zooplankton community structure occurred following the replacement of planktivorous fish by phantom midge (Chaoborus americanus) larvae as the predominant predator of zooplankton. The interannual changes following the establishment of Chaoborus included the apparent or near extinction, of species ill adapted to the new predation pressure and the successful colonization of well adapted species. Seasonal changes in the species composition and size distribution of the zooplankton community correlate with temporal variation in predation intensity associated with temperature-activity patterns of the predator or changes in the stage structure of the predator population.     

Between-year variation in flowering and fruit set in frost-prone and frost-sheltered populations of dioecious Rubus chamaemorus

Summary The flowering and fruiting patterns of the dioecious perennial herb Rubus chamaemorus L. were studied in frost-prone (open) and frost-sheltered (Shaded) habitats in northern Sweden over 6 years. The number of ramets with flower buds, the proportion of flower buds that opened, and fruit set varied markedly between years. In the frost-prone populations, the occurrence or absence of detrimental frosts during the development of flowers and fruit could explain much of the variation, both in the proportion of flower buds that developed into flowers, and in fruit set. In the frost-sheltered populations, most female flowers that did not develop into fruit aborted without any signs of physical damage and before any ovules had begun to enlarge. Flower mortality caused by herbivores feeding on reproductive parts was commonly low, but reached values higher than 10% in one of the shaded populations. Hand-pollination increased the proportion of ovules producing seeds in the mature fruits by about 20%, and in one year also increased fruit set significantly in one population. Fruit-producing female ramets had a higher mortality and a lower probability of flowering in the subsequent year than male ramets and non-fruiting female ramets. In R. chamaemorus, the conditions for fruit maturation are highly unpredictable at the time of flower initiation. It is suggested that the apparent over-initiation of flower buds is advantageous, as it allows the plant to attain a high reproductive success in years favourable for flowering and fruit development.     

蛋白和酯酶电泳在根霉鉴定上的应用

对根霉(Rhizopus)属的十个种或变种共二十四株菌的菌体可溶性蛋白和酯酶同工酶进行了电泳的研究得到对这个属分类上更多的依据.在严格控制培养,提取和电泳条件的情况下,同一株菌不同批次所得菌体蛋白电泳图谱有较好的重复性.在相同的条件下,每个种的根霉有各自特征性蛋白图谱,种内不同菌株的蛋白图谱和酯酶酶谱基本相同.特别是形态特征明显、分类地位明确的种,种内各株的图谱也较一致,如R. stolonifer;与R.circinans.在确定新变种R. delemar var. latoapicalis时,电泳图谱与R.delemar var.delema:有明显不同,起到了佐证作用.因此认为,蛋白图谱与酯酶酶谱相辅相成,在根霉种的分类中是一有效的辅助手段.     

立枯丝核菌蛋白质电泳图谱研究 Ⅰ.融合群与图谱的相关性

用来自日本和美国的立枯丝核菌8个融合群11个类群代表菌株进行可溶性蛋白质电泳,其结果表明,各融合群及亚群之间电泳图谱有显著差异,而同一类群菌株的电泳图谱则相似。分析来源于华东等地已鉴定的融合类群117个菌株的电泳图谱显示,同一融合群内菌株,虽然采集地区、寄主植物或致病力不同,其蛋白质图谱仍十分相似;而不同融合类群的菌株,即使在同一田块中同一种寄主植物上引起相似病害,其图谱也显示出明显差异。本文就上述可溶性蛋白质图谱显示的结果与其它研究者在血清学、DNA同源性.酯酶等生化水平上对融合群的研究结果进行了比较和探讨。     

Population density ofMonochamus alternatus adults (Coleoptera: Cerambycidae) and incidence of pine wilt disease caused byBursaphelenchus xylophilus (Nematoda: Aphelenchoididae)

Summary The seasonal occurrence ofMonochamus alternatus and newly weakened trees were investigated in aPinus thunbergii stand for 4 years. Adult beetles were present between June and September with a peak in their population occurring in early July followed by a decline then a period of about one month being in a steady number. The average number ofBursaphelenchus xylophilus (Nematoda), which is the causal agent of pine wilt disease, within beetles decreased as the season advanced. Pine trees newly weakened byB. xylophilus appeared between June and October, especially from August to October. The proportion of weakened or killed trees was directly proportional to the average beetle density per tree from June to August.     

Temporal and spatial relationships between an herbivorous lady beetleEpilachna niponica and its predator,the earwigAnechura harmandi

The relationships between egg predation of an herbivorous lady beetle Epilachna niponica (Lewis ) and its predator, the earwig Anechura harmandi (Burr ), were examined in both time and space. In spite of little annual, changes in egg densities, egg mortality due to predation varied considerably. There was no, clear relationship between the earwig density and the proportionate predation over the five years. The seasonal occurrence of earwig nymphs on thistle plants, however, was closely synchronized with that of egg predation. Predator attacks on the beetle occurred in a time-restricted manner. Thus, later cohorts mostly escape from heavy predatory pressure. No spatially density-depent egg predation was detected at the level of either thistle plants or thistle patches. Furthermore, there was no indication of aggregative behaviour of the earwig in response to local egg density. The earwig density was more likely to be associated with particular localities with sandy deposits available for its nest site.     

Regional influences on small-scale vegetational heterogeneity within grasslands in the Serengeti National Park,Tanzania

An index of vegetational heterogeneity in 16 grassland communities in the Serengeti National Park, Tanzania, was calculated using mean percent distance (MPD) among spatially separated quadrats. To determine whether regional factors such as annual precipitation, fire, soil sodicity, herbivore utilization, or percentage of species having clonal growth patterns influenced the amount of heterogeneity measured in individual grassland communities, the index was related to these factors by an interactively constructed multiple-regression model.Community heterogeneity varied in a curvilinear manner along a north-to-south transect; maximum values occurred in the center of the park with lower values near the northern and southern borders. Subsurface concentrations of Na⁺ and the presence or absence of mound-building termites were incorporated into the model, which explained 55% of the variability in grassland heterogeneity.Abbreviations PD= Percentage Distance - MPD= Mean Percentage Distance     

Evaluation of microwave hyperthermia applicators.

Hyperthermia has been used in conjunction with radiation and chemotherapy for cancer treatment. When using electromagnetic heating, applicators are critical components in contact with or in proximity to patients and can be the determining factor for effective and safe treatment. Tissue absorption of electromagnetic energy is determined by many factors. Three cases are shown to illustrate the complexity of microwave heating: 1) The BSD MA-151 applicator has good center heating on a muscle-only phantom as shown in the operation manual. When fat slabs of 0.25, 0.5, 1, and 2 cm thick were added, two hot spots near the periphery of the applicator were evident on all fat surfaces, exposed at 631 MHz. At 915 MHz, the heating was elongated on the surface of the models with 0.25- and 2-cm fat, and two hot spots were observed on the 0.5- and 1-cm fat surfaces. 2) Heating patterns of the Clini-Therm applicators on a muscle-only phantom, as indicated in the operations guide, are elliptical with their major axes perpendicular to the electric field. However, when a bolus is used, the elliptical pattern is parallel to the E field. 3) Heating patterns in cylindrical structures were studied with inhomogeneous models of limbs. Arm and thigh models consisting of fat, bone, and muscle material were heated with Clini-Therm L, M, and MS applicators at 915 MHz. In addition to the geometric effect, the results indicated that placing the applicators with E field parallel to the long axis of cylindrical structures can minimize required power, produce less heating of fats and reduce stray radiation. In conclusion, to apply penetrating microwave or other RF fields for tissue heating, one must simulate the clinical exposure conditions as closely as possible to obtain useful heating patterns.