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321.
Summary The larvae of flour beetles Tribolium castaneum and T. confusum were reared in two kinds of groups: full siblings and unrelated individuats. These kin and nonkin groups were reared in open cultures, in which emigration was permitted (both species) and in closed cultures, in which emigration was prohibited (only T. confusum). We measured larval development time and survivorship, weight of pupae, and time of larval emigration from open cultures. The effects of age structure were investigated by establishing open cultures of larvae of uniform age (larvae hatched from eggs laid within 72 h) and cultures of larvae of variable age (eggs laid within 240 h). In closed cultures of siblings, T. confusum larvae pupated on an average 2.2 days earlier than larvae reared in nonsibling groups. In T. castaneum, more small and medium size and fewer large size larvae emigrated from groups of siblings compared to groups of nonsiblings. Males that emigrated and pupated remained with their sibs for a shorter time than did similar males raised with unrelated larvae. In T. castaneum, age structure variation reduced the sibs tendency to migrate, but did not influence interactions among unrelated larvae. The genetical effects of kinship and the ecological effects of age structure were shown to affect the interactions of Tribolium larvae reared in groups. Reducing the similarity between individuals, either genetically or demographically (using mixed broods or mixed age cohorts), changed the pattern of larval interactions. Upon occasion, the effects of kin interactions may well be the mechanical consequences of the coexistence of similar individuals rather than the effects of altruistic behavior. 相似文献
322.
Przemys?aw?Siemion Jolanta?Jab?ońska Janusz?Kapu?niak Jacek?J.?Kozio?Email author 《Journal of Polymers and the Environment》2004,12(4):247-255
Reaction of granular potato starch with urea and biuret resulted in the formation of products, which were soluble neither in cold nor boiling water. The net reaction was a monosubstitution of the hydrogen atom in one hydroxyl group in each D-glucose unit of starch with the either CO–NH2 or CO–NH–CO–NH2 moiety, respectively. Properties of the products, particularly these with urea, depended on the mode of reaction. Reactions were carried out in the microwave oven as well as with convection heating. The products retained the granular form of starch but a vast majority of granules were damaged. -Amylolysis of those materials revealed that their susceptibility to the enzyme increasing in the order: starch-amylolysis with simultaneous insolubility in water make these products suitable as ruminant fodder and, eventually, biodegradable material. 相似文献
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324.
Magdalena Leszczyszyn-Pynka Ma?gorzata K?ys-Rachwalska Beata Sacharczuk Anna Boroń-Kaczmarska 《International journal of occupational safety and ergonomics》2004,10(4):425-429
We analyzed occupational exposure to potentially infectious body fluids among health care workers (HCWs). Nurses were the most common exposed category of HCWs. In 73.6% cases needle sticks had been the reason of exposure. Recapping a needle was the cause of exposure in 6.9% accidents. Among 189 registered HCWs, 66 (34.9%) performed invasive procedures without any personal protective equipment. Prophylaxis with antiretroviral drugs was necessary in 43 (22.8%) cases. As many as 60.3% of exposure incidents to potentially infectious material result from non-compliance with the relevant recommendations. Continuous education and training is critically needed to prevent occupational exposure to blood-borne infections among health care workers. 相似文献
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327.
The general properties of piezoelectric sorption detectors utilised in the detection of air pollution have been characterised. Examples of detection, with the aid of these detectors, of the organophosphorus compounds, sulphur dioxide, ammonia, hydrocarbons and their derivatives and other air pollutants have been given. Based on information given in this paper, general conclusions including advantages, and difficulties of using piezoelectric detectors in practice have been described. 相似文献
328.
Cadmium effects on the ovary structure and oocytes were tested in earthworms Dendrobaena veneta exposed to 10 and 50 mg Cd kg(-1) in soil after 10 and 20 days of the experiment. In both experimental doses cadmium caused damage to the structure of the ovary but the effects were different in each group. At 10 mg Cd kg(-1) concentration in soil, young stages of oocytes and trophocytes were most sensitive to cadmium deleterious effects whereas somatic cells in the ovarian stroma were only slightly affected. Cadmium. at a concentration of 50 mg Cd kg(-1) in soil caused most damage in the somatic cells leading to the occurrence of unnaturally swollen elements and desmosomes destruction. At both experimental concentrations cadmium induced degenerative changes in cell nuclei and an increase in number of cell organelles (RER and Golgi complex elements) in the cytoplasm of oocytes and trophocytes. These also proved to be more active. No ultrastructural changes were manifested in oogonia. In both experimental groups degenerative changes occurred as early as after 10 days of Cd exposure. 相似文献
329.
Krystyna Grodzińska 《Environment international》1979,2(3):173-176
The Niepo?omice Forest, a large forest complex (11,000 ha), situated about 20 km from a large steel mill and about 40 km from the city of Cracow was the object of study. Sulphur dioxide emitted by the steel mill and the city has already caused acidification of the environment of the Niepo?omice Forest. The degree of such acidification was estimated using tree bark as a bioindicator. The pH value and buffer capacity were determined for three tree species — Quercus robur, Tilia cordata and Pinus sylvestris. The bark of all trees showed acidic reaction ranging from pH 2.2 to 4.7. Difference in pH of bark were found between various localities. The bark of examined species was much more acidic in the western part in the Niepoo?mice Forest than in the eastern part of the forest complex. The buffer capacity of bark also differs in various localities increasing with SO2 concentration in the air. A good correlation between acidification of tree bark and the concentration of SO2 in the air of Niepo?omice Forest was found; therefore tree bark may be regarded as a good bioindicator and recommended for practical use to estimate the degree of air pollution. The procedure of sampling and analysis of tree bark is described in detail. 相似文献
330.
Krzysztof Baszczyński 《International journal of occupational safety and ergonomics》2006,12(3):307-318
Retractable type fall arresters are part of the equipment used for protecting people against falls from a height. They are an intermediate part between full body harness worn by a man and the structural anchor at the worksite. The most important task of retractable type fall arresters is to arrest people's falls and to reduce their harmful consequences. Information received from users as well as laboratories testing protective equipment indicates that the performance of such equipment is incorrect under specific conditions. The paper is concerned with an analysis of the conditions in which retractable type fall arresters demonstrate intermittent performance and with an explanation of that phenomenon. The results of tests investigating anchor devices and the performance of retractable type fall arresters are presented. External and internal factors contributing to intermittent performance have been determined and guidelines for safer use of these devices have been developed. 相似文献