a study was conducted to determine the copper status of different classes of grazing sheep during twodifferent seasons on a farm located in southern punjab, pakistan. a complete free-choice supplement wasavailable to all animals throughout the year. soil, forage and blood plasma from animals were taken eighttimes during the year (2005) (four times in both summer and winter seasons). soil cu2+ w...

conclusions based on these observations, wide variation is detected in the chemical composition of the oil obtained from the same plant in different seasons. materials and methods the oil was extracted by hydro-distillation from two samples collected in different seasons, and analyzed by gc-fid and gc-ms. results in total, 18 and 20 components were identified and quantified in the oil of summer...

Using rotifer-algal microcosms, we tracked rapid evolution resulting from temporally changing natural selection in ecological predator-prey dynamics. We previously demonstrated that predator-prey oscillations in rotifer-algal laboratory microcosms are qualitatively altered by the presence of genetic variation within the prey. In that study, changes in algal gene frequencies were inferred from t...

This research was conducted to find out the seasonal (monsoon and post monsoon) variation in gut contents of Labeo calbasu from June November, 2016 Dekhar haor Sunamgonj district, Bangladesh. Three orders phytoplankton were identified content viz. Bacillariophyceae (11 genera), Chlorophyceae (9 Cyanophyceae (4 genera). (6.98±1.61×103cell/L) as most dominant group. Two types zooplankton crustace...

concentrations of heavy metals (ni, co, zn, cd, pb and cu) in the reservoir of shahid rajaeidam, one of the main water reservoirs in north part of iran, were determined using a differential pulse polarography(metrohm 797 va) and compared with the national and international specified maximum contaminant levels(mcl) for different purposes of water use. the results showed that concentrations of cd...

Rotifers have often been used as indicators of sudden changes in physical and chemical features of the aquatic environment. Such features vary greatly during flood pulse events in small lakes connected to major floodplains. However, few are the studies that investigate the consequences of the flood pulse in rotifer species composition, abundance, richness and diversity, especially in Amazonian ...

Mechanisms underlying competitive interactions are important in understanding the structure of planktonic communities, particularly the coexistence of similar species. Here we present experimental results of exploitative competition among three sympatric sibling species of the Brachionus plicatilis complex for two differently-sized species of food microalgae. These three rotifer species are to ...

conclusions because the intestinal parasitic infections are a health concern in areas with poor nutritional and socioeconomic status, intervention programs, including health education and environmental sanitation, are required. background intestinal parasitic infections are one of major health problems, especially in developing countries. several factors, such as geographical location and socio...

vehicle exhaust is a major source of exposure to polycyclic aromatic hydrocarbons (pahs) found in the urban atmosphere. newsagents usually work close to heavy traffic flow. the purpose of this study was to assess the breathing zone exposure of newsagents to pahs found in the urban atmosphere of tehran city during summer and autumn seasons and comparing the levels of exposure in both seasons.fif...

Temperature-Size Rule (TSR) is a phenotypic body size response of ectotherms to changing temperature. It is known from the laboratory studies, but seasonal patterns in the field were not studied so far. We examined the body size changes in time of rotifers inhabiting activated sludge. We hypothesize that temperature is the most influencing parameter in sludge environment, leading sludge rotifer...