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111.
Ecology of kin and nonkin larval interactions in Tribolium beetles   总被引:1,自引:0,他引:1  
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   
112.
The thermal environment in the workplace is an important factor which affects workers’ health. During 2011 in Poland, 14,781 workers were exposed to a cold working environment, i.e., 3.8% of persons employed in hazardous work conditions. The aim of this study was to determine the cardiovascular response to continuous (4 °C for 60 min) and intermittent (10 min at 4 °C and 10 min at room temperature alternately) exposure to the cold in 30 healthy men aged 20–27 years. Peripheral blood flow was assessed with impedance plethysmography. Heart rate and arterial blood pressure were monitored with the Holter system. Having assessed the results, it is difficult to say which kind of exposure has a more severe impact on the cardiovascular system. Longer observation and a more detailed analysis would be necessary (e.g., Doppler echocardiography).  相似文献   
113.
This paper reports results of gamma and alpha spectrometric measurements for mosses, lichens, fungi and soil samples from areas in the Balkans targeted by depleted uranium (DU). Samples were collected in 2002 and 2003 in the vicinity of several villages, principally Han Pijesak (Bosnia and Herzegovina, hit by DU in 1995) and Bratoselce (South Serbia, hit by DU in 1999) and in lesser numbers from Gornja Stubla, Kosovo (which is identified as a high natural radon/thoron area) and Presevo close to the Kosovo border. In the course of gamma spectrometric measurements some results suggested samples with unusual high uranium contents which might be considered to be a signature for the presence of DU, although many samples had very high detection limits. Alpha spectrometric measurements directly proved the presence of DU for five samples, all from directly targeted places. These were samples of mosses, lichens and soil. For some samples homogeneity tests were applied which showed a rather even distribution of DU in these samples. No trace of DU was found in any sample from a dwelling.  相似文献   
114.
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   
115.
Interests in the determination of different arsenic species in natural waters is caused by the fact that toxic effects of arsenic are connected with its chemical forms and oxidation states. In determinations of water samples inorganic arsenate (As(III), As(V)), methylated metabolities (MMAA, DMAA) and other organic forms such as AsB, AsC, arsenosugars or arsenic containing lipids have the most importance. This article provides information about occurrence of the dominant arsenic forms in various water environments. The main factors controlling arsenic speciation in water are described. The quantification of species is difficult because the concentrations of different forms in water samples are relatively lowcompared to the detection limits of the available analytical techniques. Several hyphenated methods used in arsenic speciation analysis are described. Specific advantages and disadvantages of methods can define their application for a particular sample analysis. Insufficient selectivity and sensitivity of arsenic speciation methods cause searching for a new or modifications already existing techniques. Some aspects of improvement and modifications of the methods are highlighted.  相似文献   
116.
Cd, Zn, Cu, and metallothionein (MT) levels have been determined in the renal cortex and liver of 70 persons who died in Lodz and its surroundings in the years 1985–1989. The mean concentrations were: 44.9±28.6 µg Cd/g, 52.0±16.7 µg Zn/g, 2.4±1.0 µg Cu/g, 0.79±0.40 µmol Hg/g, and 3.5±1.8 µg Cd/g, 66.7±30.5 µg Zn/g, 4.9±2.1 µg Cu/g, 0.50±0.38 µmol Hg/g wet tissue in renal cortex and liver, respectively, with mean age 54.0±13.8. Smokers showed 2.4 times higher levels of Cd in the renal cortex than non-smokers. The mean body burden of Cd was 33.4±17.3 mg. Smoking increases it twofold from 22.0 mg in non-smokers to 41.8 mg in smokers.This work was supported by the grant CPBR 11.12(C-56/86) from the Institute of Rural Medicine, Lublin, Poland.Deceased.  相似文献   
117.
Polymeric materials are among the most promising, effective, and increasingly important adsorbents for the removal of toxic metals from wastewater. This study was dedicated to the development of an insoluble, modified chelating polymer for use as an adsorbent for abstraction of Hg from aqueous solutions. Cross-linked polyethylenimine (CPEI) was sulfonated by 3-chloropropanesulfonyl chloride for selective removal of Hg. The binding affinity of the sulfonated CPEI (SCPEI) to Hg was assessed as well as its ability to be regenerated for reuse. It exhibited high removal percentage for Hg up to 87% in synthetic solutions, with high selectivity even in the presence of competing ions: “Mn, Ni, Fe, Pb, Zn, and Cr.” The removal mechanism followed was observed to be adsorption and precipitation at pH 3 and 8, respectively. High adsorption capacities were also observed for wastewater to which the polymer was applied. The Freundlich isotherm was found to be the best fit describing the adsorption process of Hg onto the SCPEI. The pseudo second-order equation was found to better explain the adsorption kinetics, implying chemisorption. The thermodynamic study of the adsorption revealed high activation energies which confirmed the chemisorption as the mechanism of adsorption. The polymer exhibited up to 72% removal efficiency after regeneration, thus showing potential for re-use.  相似文献   
118.
Release of Cd immobilized by soil constituents (clay, humic acids, bacterial cells) in vitro and under soil conditions and its bioavailability to lettuce were studied. The most resistant to extraction with 0.02 M EDTA in vitro as well as under soil conditions was cadmium immobilized by humic acids during decomposition of contaminated plant residues but Cd‐dead cells when 0.1 M NaNO3 was the extractant.

Cadmium addition (3 mg kg‐1) to soil and its form were without effect on plant growth and amount of metal accumulated in roots. Tops of plants grown in soil supplemented with Cd‐resting cells contained significantly less metal then other ones.  相似文献   
119.
Regular physical activity may be a tool in the prevention of sedentary behaviour, overweight, obesity, and obesity-related diseases and plays a fundamental role in health promotion. Moreover, it helps to educate, to develop tolerance and respect for others, to increase interindividual and international exchange, plays a role in social integration, and contributes to an increase in individual sustainable development (ISD). ISD is an extension of the concept of the sustainable development (SD). Its aim is to promote a long, healthy and autonomous life, in conformity with the physical and social environment and economic needs. ISD implies individual participation in the decision-making process, self-determination and freedom and/or responsibility in making individual choices.  相似文献   
120.
To abate the severe acidification of Swedish lakes are about 7% directly limed (AL-lakes). These are important to include when assessing acidification. Consequently, we need to estimate their chemical status as if they were not lime-affected. We hypothesize that there is a spatial dependence for calcium (Ca) and magnesium (Mg) concentrations. Spatial variation is determined using variograms. We study lakes within two 150 ∗ 150 km quadrates (EMEP150-grid) in the middle and southern parts of Sweden. We model Ca in AL-lakes using the Ca and Mg concentrations in nearby, unaffected lakes (UL-lakes). The mean Ca/Mg for the three or seven closest UL-lakes is used. We assume that Ca/Mg is constant for UL-lakes and that Mg unaltered by liming. For UL-lakes, Ca and Mg are spatially dependent. For AL-lakes, there is a spatial dependence for Mg, but, as anticipated, not for Ca. The modeled Ca for UL-lakes show a good correspondence with measured Ca; r 2 > 0.6; slopes close to 1 and intercepts almost 0. Using three or seven nearby lakes when modeling Ca give similar results. Modeled Ca was higher than measured Ca for 36% (three closest lakes) and 38% (seven closest) of the modeled AL-lakes in the middle part of Sweden. The corresponding results for the southern part were 10% and 9%, respectively. This model is an acceptable estimator of Ca in limed lakes and for estimating critical loads and acidification status on an EMEP-scale.  相似文献   
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