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131.
132.
Optimality of parental investment: The influence of nursing on reproductive success of mother and female young house mice 总被引:1,自引:1,他引:0
Stefan Fuchs 《Behavioral ecology and sociobiology》1982,10(1):39-51
Summary The amount of parental milk investment determines not only the number of young the parent can produce, but also affects the offspring's fitness. The antagonism between quantity and quality of offspring was investigated in laboratory mice.In nursing first litters containing 2,4, ..., 14 pups, mothers invested increasing amounts of milk. This mainly extended the intervals between their first and second litters and slightly increased the size of their second litters, whilst third litters were not affected. In the female young, the decreasing amount each individual received as a result of increasing litter size led to delayed birth and reduced the size of their first litters. The intervals between their first and second litters and the size of the second litters were also affected, although to a lesser extent.Taking these results into consideration on a standard lifetime pattern of reproduction, the effects were calculated on net reproductive rates as an expression of fitness. Death rates were assumed that referred to population equilibrium or population growth. In both situations, the fitness curves of mothers and young showed that the actual level of milk investment and the level yielding optimal reproduction were in agreement. There was no significant deviation towards increased investment, as might result from parent-offspring conflict. 相似文献
133.
Bikit I Slivka J Conkić Lj Krmar M Vesković M Zikić-Todorović N Varga E Curcić S Mrdja D 《Journal of environmental radioactivity》2005,78(1):11-19
The widespread public belief that during the bombardment of Vojvodina (Yugoslavia) this region was contaminated by depleted uranium has recently raised public concern with respect to the potential contamination of agricultural products due to soil radioactivity. Based on the gamma-spectrometric analysis of 50 soil samples taken from the region of Vojvodina we concluded that there is no increase of radioactivity that could endanger the food production. Taking into account the transfer factors of 137Cs to plants, the measured activity concentrations of this isotope should not endanger the health safety of the produced food. No traces of depleted uranium have been found. The natural radioactivity levels are compared with the results form other countries. 相似文献
134.
135.
For sulfonamides, the formation of non-extractable residues has been identified by laboratory testing as the most relevant concentration determining process in manured soil. Therefore, the present study has been focused on the chemical and biological characterization of non-extractable residues of 14C-labeled sulfadiazine or sulfamethoxazole. In laboratory batch experiments, the test substances were spiked via standard solution or test slurry to microbially active soil samples. After incubation periods of up to 102 d, a sequential extraction technique was applied. Despite the exhaustive extraction procedure, sulfadiazine residues mainly remained non-extractable, indicating the high affinity to the soil matrix. The remobilization of non-extractable 14C-sulfadiazine residues was monitored in the activated sludge test and the Brassica rapa test. Only small amounts (<3%) were transferred into the extractable fractions and 0.1% was taken up by the plants. In the Lumbricus terrestris test A, the release of non-extractable 14C-sulfamethoxazole residues by the burrowing activity of the earthworms was investigated. The residues mainly remained non-extractable (96%). The L. terrestris test B was designed to study the immobilization of 14C-sulfamethoxazole in soil directly after the test slurry application. The mean uptake by earthworms was 1%. Extractable and non-extractable residues amounted to 5% and 93%, respectively. Consequently, the results of all tests confirmed the high affinity of the non-extractable sulfonamide residues to the soil matrix. 相似文献
136.
137.
Mutavdzić D Brnardić I Kastelan-Macan M 《Journal of environmental science and health. Part. B》2006,41(7):1085-1101
The purpose of this investigation was to determine the influence of humic acids (HA) and Ca-montmorillonite (CaM) on the solid-phase extraction (SPE) efficiency of atrazine, alachlor and alpha-cypermethrin from water samples at various pH-values. The nature and intensity of binding of the studied pesticides to CaM were determined by X-ray diffraction analysis and termogravimetric analysis (TGA) test. The studied pesticides eluted from discs were analysed by thin-layer chromatography (TLC). The effects of CaM and humic acid were generally pH-dependent and acted independently in extraction efficiency influence. Lower recovery of pesticides was observed at higher pH values when CaM was > or =0.1 g and was attributed to greater dispersion of clay, increased surface area and subsequent adsorption. Concentrations of dissolved organic carbon (DOC) in humic acid had less effect on the extraction efficiency when water was at pH 8 compared to water at pH 2, which was probably due to greater nonpolar interactions of the pesticides to the charge-neutralized humic acid molecule. 相似文献
138.
Antić-Mladenović Svetlana Kresović Mirjana Čakmak Dragan Perović Veljko Saljnikov Elmira Ličina Vlado Rinklebe Jörg 《Environmental geochemistry and health》2019,41(1):249-266
Environmental Geochemistry and Health - Extreme flooding in May, 2014 affected the sub-catchments of six major rivers in Serbia. The goal of the study was to evaluate the contents of potentially... 相似文献
139.
140.
Halbert-Howard Aladdin Häfner Franziska Karlowsky Stefan Schwarz Dietmar Krause Ariane 《Environmental science and pollution research international》2021,28(42):59304-59304
Environmental Science and Pollution Research - The average nutrient concentrations values presented in Table 1 on page 4 in the publication have the unit mg L?1 for the mineral nutrients Fe,... 相似文献