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41.
井下高温作业的矿工生理、生化测定研究 总被引:4,自引:1,他引:3
邢娟娟 《中国安全科学学报》2001,11(4):45-48
对煤矿井下高温作业的矿工进行了生理和生化方面的测定研究。测定与分析结果显示高温井下工人血浆中乳酸 (RU )及热应激蛋白 (HSPs)等指标明显高于非高温井下工人对照组 ,并具有非常显著统计学意义。班中体温以及班前、后体重差值也具有非常明显的差异 ,研究结果表明 ,井下高温作业环境对矿工健康有很大影响 ,应加强对这些矿工的劳动保护 相似文献
42.
Mikael Hake 《Behavioral ecology and sociobiology》1996,39(2):71-76
Relationships between social status and levels of body reserves stored by members of greenfinch (Carduelis chloris) flocks in winter were investigated. In addition, the adjustment of reserves by birds of different rank to experimental changes
in food predictability and to changed weather conditions were examined. Birds with low social status carried overall larger
body reserves than high-ranked birds. The results of the experiments suggest that this was mainly because subordinates, due
to their low priority to food access, perceived future foraging success as less predictable than dominants. In response to
severe weather, which probably increased the risk of starvation for birds, dominants temporarily increased their reserves
more than subordinates. This response also indicated that birds with low social status carried larger reserves than high-ranked
birds, and demonstrated that dominants could increase food intake when there was a risk of energetic shortfall. The results
suggest that fattening strategies in greenfinches depend on social status. In winter, subordinates may be forced to carry
larger reserves than dominants to safeguard against social constraints in access to food during critical times. As body reserves
may be costly to carry and acquire, this should reduce the probability of surviving the winter for subordinates compared to
dominants.
Received: 2 March 1995/Accepted after revision: 13 April 1996 相似文献
43.
A predator's foraging performance is related to its ability to acquire sufficient information on environmental profitability. This process can be affected by the patchy distribution and clustering of food resources and by the food intake process dynamics.We simulated body mass growth and behaviour in a forager acting in a patchy environment with patchy distribution of both prey abundance and body mass by an individual-based model. In our model, food intake was a discrete and stochastic process and leaving decision was based on the estimate of net energy gain and searching time during their foraging activities. The study aimed to investigate the effects of learning processes and food resource exploitation on body mass and survival of foragers under different scenarios of intra-patch resource distribution.The simulation output showed that different sources of resource variability between patches affected foraging efficiency differently. When prey abundance varied across patches, the predator stayed longer in poorest patches to obtain the information needed and its performance was affected by the cost of sampling and the resulting assessment of the environment proved unreliable. On the other hand, when prey body mass, but not abundance, varied among the patches the predator was quickly able to assess local profitability. Both body mass and survival of the predator were greatly affected by learning processes and patterns of food resource distribution. 相似文献
44.
BriAnne Addison Alexander S. Kitaysky J. Mark Hipfner 《Behavioral ecology and sociobiology》2008,63(1):135-141
Sex allocation theory posits that mothers should preferentially invest in sons when environmental conditions are favorable
for breeding, their mates are of high quality, or they are in good body condition. We tested these three hypotheses in rhinoceros
auklets (Cerorhinca monocerata), monomorphic seabirds that lay a single-egg clutch, in 2 years that differed in environmental conditions for breeding. Results
supported the environment and mate quality hypotheses, but these effects were interactive: offspring sex was independent of
paternal traits in the poor year for breeding, while females mated to larger and more ornamented males reared more sons in
the better year. Conversely, offspring sex was unrelated to female condition, as indexed by hatching date. We propose that
good rearing conditions enable females to rear sons possessing the desirable phenotypic attributes of their mates. Results
also supported two critical assumptions of sex allocation theory: (1) dimorphism in offspring condition at independence: daughters
fledged with higher baseline levels of corticosterone than sons and (2) differential costs of rearing sons versus daughters:
mothers rearing sons when environmental conditions were poor completed parental care in poorer condition than mothers rearing
daughters in the same year and mothers rearing either sex when conditions were better. These novel results may help to explain
the disparate results of previous studies of avian sex allocation. 相似文献
45.
46.
The effect of nitrate concentration on sulfide-driven autotrophic denitrification in marine sediment 总被引:3,自引:0,他引:3
Copepods have been widely used to evaluate toxicity of metals present in marine environments. However, a technical difficulty is to understand the possible routes of metal uptake and to identify in which tissues or organs metals are being accumulated. Traditional techniques are hard to be employed once each organ has to be analyzed separately. Autoradiography is an alternative technique to circumvent this limitation, since metal distribution in tissues can be visualized and quantified, even in small organisms like copepods. In the present study, accumulation and distribution of 64Cu in the copepod Calanus hyperboreus was studied using autoradiography. Copepods were exposed for 2 h to copper (2.3 mg L−1; 1.08 MBq 64Cu mg−1 Cu) and then allowed to depurate for 2 h in clean seawater. Total 64Cu was determined by gamma-spectrometry after a metal exposure and a depuration period. 64Cu distribution was determined based on images generated by autoradiography. Metal accumulation was observed on all external surfaces of the copepods, being accumulated mostly on the ventral region, followed by dorsal, urossoma and internal regions. After depuration, radioactivity levels had a decrease in the sum of external body surface. Our results show that copper uptake by C. hyperboreus is fast and that a non-negligible proportion of the accumulated metal can reach internal tissues, which may lead to detrimental physiological effects. Moreover, whole-body autoradiography was demonstrated to be an efficient technique to study copper accumulation and body distribution in a very small organism such as the copepod C. hyperboreus. 相似文献
47.
Stable nitrogen isotopic composition (δ15N) of aquatic biota increases with anthropogenic N inputs such as sewage and livestock waste downstream. Increase in δ15N of riparian spiders downstream may reflect the anthropogenic pollution exposure through predation on aquatic insects. A two-source mixing model based on stable carbon isotopic composition showed the greatest dependence on aquatic insects (84%) by horizontal web-building spiders, followed by intermediate (48%) and low (31%) dependence by cursorial and vertical web-building spiders, respectively. The spider body size was negatively correlated with the dietary proportion of aquatic insects and spider δ15N. The aquatic subsidies transported anthropogenic N to smaller riparian spiders downstream. This transport of anthropogenic N was regulated by spider’s guild designation and body size. 相似文献
48.
Risk assessment of PCDD/Fs levels in human tissues related to major food items based on chemical analyses and micro-EROD assay 总被引:1,自引:0,他引:1
H.L. Tsang S.C. Wu C.K.C. Wong C.K.M. Leung S. Tao M.H. Wong 《Environment international》2009,35(7):1040-1047
Nine groups of food items (freshwater fish, marine fish, pork, chicken, chicken eggs, leafy, non-leafy vegetables, rice and flour) and three types of human samples (human milk, maternal serum and cord serum) were collected for the analysis of PCDD/Fs. Results of chemical analysis revealed PCDD/Fs concentrations (pg g− 1 fat) in the following ascending order: pork (0.289 pg g− 1 fat), grass carp (Ctenopharyngodon idellus) (freshwater fish) (0.407), golden thread (Nemipterus virgatus) (marine fish) (0.511), chicken (0.529), mandarin fish (Siniperca kneri) (marine fish) (0.535), chicken egg (0.552), and snubnose pompano (Trachinotus blochii) (marine fish) (1.219). The results of micro-EROD assay showed relatively higher PCDD/Fs levels in fish (2.65 pg g− 1 fat) when compared with pork (0.47), eggs (0.33), chicken (0.13), flour (0.07), vegetables (0.05 pg g− 1 wet wt) and rice (0.05). The estimated average daily intake of PCDD/Fs of 3.51 pg EROD-TEQ/kg bw/day was within the range of WHO Tolerable Daily Intake (1–4 pg WHO-TEQ/kg bw/day) and was higher than the Provisional Tolerable Daily Intake (PMTL) (70 pg for dioxins and dioxin-like PCBs) recommended by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) [Joint FAO/WHO Expert Committee on Food Additives (JECFA), Summary and conclusions of the fifty-seventh meeting, JECFA, 2001.]. Nevertheless, the current findings were significantly lower than the TDI (14 pg WHO-TEQ/kg/bw/day) recommended by the Scientific Committee on Food of the Europe Commission [European Scientific Committee on Food (EU SCF), Opinions on the SCF on the risk assessment of dioxins and dioxin-like PCBs in food, 2000.]. However, it should be noted that micro-EROD assay overestimates the PCDD/Fs levels by 2 to 7 folds which may also amplify the PCDD/Fs levels accordingly. Although the levels of PCDD/Fs obtained from micro-EROD assay were much higher than those obtained by chemical analysis by 2 to 7 folds, it provides a cost-effective and rapid screening of dioxin levels in food and human samples. 相似文献
49.
Relationships between hepatic trace element concentrations, reproductive status, and body condition of female greater scaup 总被引:1,自引:0,他引:1
Shannon S. Badzinski Paul L. Flint 《Environmental pollution (Barking, Essex : 1987)》2009,157(6):1886-1893
We collected female greater scaup (Aythya marila) on the Yukon-Kuskokwim Delta, Alaska during two breeding seasons to determine if concentrations of 18 trace elements in livers and eggs were elevated and if hepatic concentrations correlated with body condition or affected reproductive status. Fifty-six percent, 5%, and 42% of females, respectively, had elevated hepatic cadmium (Cd: >3 μg g−1 dry weight [dw]), mercury (Hg: >3 μg g−1 dw), and selenium (Se: >10 μg g−1 dw). Somatic protein and lipid reserves were not correlated with hepatic Cd or Hg, but there was a weak negative correlation between protein and Se. Hepatic Cd, Hg, and Se were similar in females that had and had not initiated egg production. In a sample of six eggs, 33% and 100%, respectively, contained Se and Hg, but concentrations were below embryotoxicity thresholds. We conclude that trace element concentrations documented likely were not adversely impacting this study population. 相似文献
50.
Live feeds, especially Tubifex spp., which are collected from a wide variety of polluted habitats, are used by aquarium fish keepers in India. These habitats
receive domestic sewage and industrial wastes from nearby residential and industrial areas. Reports of morbidity and mortality
from aquarium fish culturists in and around Mumbai led to the present investigations on the ecology of these habitats with
a view to assess the water quality, presence of heavy metals in the environment and their bioaccumulation in Tubifex worms, and to examine whether these habitats could be exploited to meet the demand of the industry. Six natural red worm
(Tubifex spp.) collection centres in Mumbai and Thane districts of Maharashtra state in India constituting a major source of live
Tubifex supply to aquarium fish industry were evaluated for pollution, heavy metal concentration in water, sediments and in the body
tissues of Tubifex. Data revealed the presence of heavy metals in water and sediments at collection sites and bioaccumulation of cadmium, iron,
lead, zinc and copper in body tissues of Tubifex worms. Cadmium ranged from 2.38 to 7.21 mg/kg, iron 671.9 to 5738 mg/kg, lead 14.95 to 33.49 mg/kg, zinc 60.20 to 166.60 mg/kg
and copper 29.38 to 108.90 mg/kg of dry Tubifex worms. The study suggests that all the six collection sites are polluted and the red worms contaminated with heavy metals
and hence, unfit for use in aquaria or feeding any variety of fish or crustaceans in the hatcheries. 相似文献