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91.
92.
Male-biased predation of a cave fish by a giant water bug 总被引：1，自引：0，他引：1
Male-biased predation has been described from several epigean species, and in many cases, intrinsic differences between the sexes (such as male ornaments) have been suggested as an explanation. Here we report on male-biased predation of a cave fish (Poecilia mexicana) by an aquatic insect (Belostoma sp.) in a Mexican sulfur cave. P. mexicana use aquatic surface respiration (ASR) to survive in their sulfidic, hypoxic habitat. We found that males typically exhibit more ASR activity than females, which leads to increased exposure to the sit-and-wait predator that catches fish near the water surface. Our finding is novel, because male vulnerability to predation is not directly related to male traits involved in courtship, but rather due to other sexual differences in behavior and ultimately, oxygen demands. 相似文献
93.
Haixiao Wu 《中国人口．资源与环境(英文版)》2016,14(1):11-15
There is an increasing number of “mass events” in mainland China. My study extends the current studies to the context of China and tries to examine the potential impacts of climate changes on human conflicts in China. The results suggest a strong linkage between the deviation of monthly mean temperature from the historical mean and the number of mass events in a province. If the current trend of warming persists, in the next 6–8 decades, the number of mass events in China will increase by over 8.8%. 相似文献
94.
This work aimed the evaluation of a saline extractive distillation for the ethanol production. A thermodynamic model was used to predict the influence of the salts in the liquid–vapor equilibrium of the system water–ethanol and inside the packed column. The experiments were done in a distillation unit, with an internal diameter of 5.9 cm and a packing section with 37 cm of height, packed with raschig rings with 0.73 cm of characteristic inner made of glass. All the bottom and top samples were analyzed by refractive index. Two synthetic charges with the same composition of ethanol that are produced in the refinery (0.02 and 0.25 mol.L-1) were distilled under atmospheric pressure. Sodium chloride, calcium chloride, potassium acetate, calcium nitrate and a mixture of sodium and potassium acetates were added to the synthetic charges and the results were compared to the experiments already done without the presence of the salts, revealing the ethanol enrichment in the top product of the distillation unit, for all the systems analyzed. Another charge from the refinery, known as load of wine without yeast, was evaluated and the results indicated the same behavior, enriching the ethanol with the application of the saline extractive distillation. 相似文献
95.
生物化学法净化低浓度甲苯废气的传质研究 总被引：3，自引：0，他引：3
通过试验和理论分析,研究生物化学法净化低浓度甲苯废气这一传质一生化反应过程的控制因素,结果表明生物化学法净化低学本废气为传播控制过程,并以气膜控制为主,研究为工业化装置的设计和操作提供了理论依据。 相似文献
96.
A. L. Jensen 《Environmetrics》2001,12(6):591-598
Natural mortality of fish populations is difficult to estimate, and parameters for growth and environmental temperature, which are easier to estimate, have been applied to predict fish natural mortality using multiple linear regression. There are theoretical relations among all of the variables applied in the multiple linear regression, and there is high multicollinearity; the results of the multiple regression differ considerably from the theoretical relations among the variables. Simple linear regression results agree with the theoretical results but they are not as precise for prediction of mortality as multiple linear regression. A principal components analysis correctly identifies the important variables and the relations among variables but it is more complex than multiple linear regression and yet is not any more precise for predictions. A plot of the first two principal components separated the data into two groups: one was temperate water species and one was warmer water species. The analysis confirms the limitations and advantages of different data analysis methods. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
97.
苯并芘(B[a]P)已广泛分布于海洋环境中,低等海洋无脊椎动物从受精卵开始整个生长发育过程都面临着B[a]P等多环芳烃类污染物(PAHs)的威胁.本实验以热带海洋优势贝类马氏珠母贝(Pinctada maetensii)作为材料,研究B[a]P对马氏珠母贝D型面盘幼虫发育的影响.将幼虫暴露于不同浓度(]、2、4、10和]5μg·L-1)B[a]P中,在暴露后第12、24、36、48、72、84小时,分别测定其D型面盘幼虫的死亡率和畸形数.结果表明:B[a]P对D型面盘幼虫死亡率的影响明显,死亡率与时间呈正相关,其中4和10 μg·L-1浓度组的响应最敏感.在1～10μg·L-1浓度范围内,死亡 相似文献
98.
Participatory epidemiology methods were employed retrospectively in three pastoralist regions of Ethiopia to estimate the specific causes of excess livestock mortality during drought. The results showed that starvation/dehydration accounted for between 61.5 and 100 per cent of excess livestock mortality during drought, whereas disease‐related mortality accounted for between 0 and 28.1 per cent of excess mortality. Field observations indicate that, in livestock, disease risks and mortality increase in the immediate post‐drought period, during rain. The design of livelihoods‐based drought response programmes should include protection of core livestock assets, and it should take account of the specific causes of excess livestock mortality during drought and immediately afterwards. This study shows that, when comparing livestock feed supplementation and veterinary support, relatively more aid should be directed at the former if the objective is to protect core livestock during drought. Veterinary support should consider disease‐related mortality in the immediate post‐drought period, and tailor inputs accordingly. 相似文献
99.
《环境科学学报(英文版)》2024,36(2):422-436
The present study aimed to evaluate multi-element concentrations (Al, As, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Pb, Sr) in suspended particulate material (SPM) collected from Ensenada de La Paz (ELP) lagoon, Baja California Sur, Mexico in two different periods (September and May) to comprehend their origin, geochemical behavior, mass transfer and associated ecotoxicological risks. The 24 hr variation coefficient of volumetric SPM levels were found to be 51.7% in September and 40.5% in May, signifying the effects of oceanic waters. The calculated enrichment factor (EF) values for all the studied elements were of higher magnitude because of the high surface area and oxide nature of SPM, and in this study, Mo had the highest EF of 46.77 probably due to its origin from continental weathering. From the ecotoxicological perspective, the integrated toxic risk index revealed low toxic risk to the benthic community. However, the mean-ERM-Quotient calculated using the particulate concentrations of As, Cd, Cr, Cu, Ni, Pb indicated 9% probability of toxicity to biota. The comprehensive geochemical and ecotoxicological assessment of particulate metal concentrations in the ELP lagoon signify low to moderate contamination. 相似文献
100.
In order to define the mortality criteria of planarian objectively, a case study of Dugesia japonica exposed to 1-octyl-3-methylimidazolium bromide ([C8mim]Br) was performed followed by a recovery culture. The results showed that defining planarian mortality in light of its body disintegration was appropriate. If the disintegrated tissue of a planarian was more than 1/4 of its body length, it would completely degenerate. However, a planarian would regenerate the lost tissue and return to normal after a few days' recovery culture if the disintegrated part was less than 1/4 of body length. Therefore, we propose to use body disintegration as the endpoint of planarian mortality, i.e., 1/4 body length degenerated is the critical threshold of mortality and survival of planarians when exposed to toxicants. This criterion could be adapted in the standardization of testing protocols and comparability of acute toxicity test or other toxicological research using planarian as the test animal. 相似文献