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91.
The objective of this paper is to compare the following four methods of measuring oxygen transfer in wastewater treatment plants under process conditions: the offgas, hydrogen peroxide (H2O2), reaeration, and in situ oxygen uptake rate (OUR) methods. Comparative tests were performed under controlled conditions in a pilot column and in six full-scale oxidation ditches equipped with fine-bubble diffusers and slow-speed mixers. The offgas and H2O2 methods give similar results (differences between the oxygen-transfer coefficients under field conditions [k(L)a(f)] from each method lower than 10%). The reaeration procedure gives more random results (differences from -5 to -43% compared with values obtained using the offgas method). The in situ OUR method, in the presence of a horizontal flow of mixed liquor, leads to an estimate of k(L)a(f) to within 15% of the offgas value. 相似文献
92.
93.
Anne-Leila Meistertzheim Isabelle Calvès Valérie Roussel Alain Van Wormhoudt Jean Laroche Sylvain Huchette Christine Paillard 《Marine Biology》2014,161(8):1883-1893
Increasing temperature of seawater is often associated with increased exposure incidence of disease in field and in aquaculture populations. Numerous episodic mass mortalities of the abalone Haliotis tuberculata have been observed along the northern Brittany coast of France caused by a complex interaction between the host, pathogen and environmental factors. Here, we evaluated the potential of high-resolution melting (HRM) analysis for mutation genotyping and development of genetic markers for resistance to vibriosis in the gastropod species H. tuberculata. Small amplicon assays were developed and revealed genetic polymorphism between surviving and susceptible abalone obtained after two successive infections of aquaculture families in controlled conditions. Together with specific COI haplotypes, we identified particular genotypes in nascent polypeptide-associated complex subunit alpha and ferritin genes linked to the susceptibility or resistance of abalone to vibriosis. Selection of genitors based on these genes may increase the proportion in offspring of resistant individuals of more than 76 %. Finally, HRM assays constitute a very efficient genotyping tool to validate the genetic markers on a representative number of individuals of wild populations and thus identify future resistant genitors for aquaculture or conservation purposes. 相似文献
94.
Sugimoto JD Labrique AB Ahmad S Rashid M Shamim AA Ullah B Klemm RD Christian P West KP 《Disasters》2011,35(2):329-345
The epidemiology of tornado-related disasters in the developing world is poorly understood. An August 2005 post-tornado cohort study in rural Bangladesh identified elevated levels of death and injury among the elderly (≥ 60 years of age) (adjusted odds ratio (AOR) = 8.9 (95 per cent confidence interval (CI): 3.9-20.2) and AOR = 1.6 (95 per cent CI: 1.4-1.8), respectively), as compared to 15-24 year-olds, and among those outdoors versus indoors during the tornado (AOR = 10.4 (95 per cent CI: 5.5-19.9) and AOR = 6.6 (95 per cent CI: 5.8-7.5), respectively). Females were 1.24 times (95 per cent CI: 1.15-1.33) more likely to be injured than males. Elevated risk of injury was significantly associated with structural damage to the house and tin construction materials. Seeking treatment was protective against death among the injured, odds ratio = 0.08 (95 per cent CI: 0.03-0.21). Further research is needed to develop injury prevention strategies and to address disparities in risk between age groups and between men and women. 相似文献
95.
In the polydomous ant species Cataglyphis iberica, nests belonging to the same colony are completely separated during hibernation. In order to examine whether this separation
induces changes both in the hydrocarbon profile and in recognition ability between adult nestmates, we separated groups of
workers for several months under two different conditions: at hibernation temperature and at room temperature. At room temperature,
recognition remained unchanged but separation led to longer mutual antennations relative to non-separated controls. When half
of a colony was placed under hibernation conditions, antennal interactions also increased in duration and a few aggressive
interactions emerged between separated ants. This aggressiveness never reached the intercolonial level observed in this species.
In both cases, the hydrocarbon profiles showed differences between individuals after separation while remaining homogeneous
within each nest. This chemical modification may induce the longer antennations observed. After separated groups were reunited,
individuals recovered their previous antennation pattern and a convergence in hydrocarbon profiles was again observed. These
concurrent observations suggest that hydrocarbons are transferred between nestmates. In C. iberica, the formation of the colonial odor seems to follow the “Gestalt” model which allows all satellite nests of a colony to have a common colonial odor. In the field, temporary nest isolation
during hibernation may induce divergence between satellites. The role of adult transport in connecting nests during the active
season to obtain an efficient Gestalt odor is discussed.
Received: 16 June 1997 / Accepted after revision: 25 October 1997 相似文献
96.
Nancy McCarthy Elisabeth Sadoulet Alain de Janvry 《Journal of Environmental Economics and Management》2001,42(3):297
In addition to the usual fixed costs, we introduce variable costs in a community's effort to cooperate in extracting from a common pool resource. Using a standard supervision mechanism, these variable costs are shown to be an increasing function of individual members' incentives to default. The model explains why we frequently observe communities that all cooperate and have relatively similar resource endowments, and yet achieve very different levels of extraction. 相似文献
97.
Energy planners in developing countries have traditionally sought to meet their nations' growing electricity demands by adding more generation and transmission capacity. But as the foreign investment situation became critical in the 1980s, private investment and system efficiency improvement programmes began to garner interest. One of the most promising system efficiency improvement options is load management, which uses a variety of techniques to utilize the electricity system's existing capacity more efficiently. However, to date, only three countries have seriously considered implementing large load management programmes: Pakistan, Peru and Costa Rica. This paper describes a 1987-89 load control demonstration programme in Costa Rica, sponsored by the US Agency for International Development (AID), in which participating industries were able to reduce their peak demand by 14%. 相似文献
98.
Daniel Houle Christian Gagnon Suzanne Couture Alain Kemp 《Water, Air, & Soil Pollution: Focus》2004,4(2-3):247-261
Since 1985, monitoring activities have been conducted in a networkof 43 lakes comprising the Québec portion of the Long-Range Transport of Airborne Pollutants (LRTAP) program. The results to date indicate that Québec lakes generally are responding positively to the generalized decline in precipitation sulfate (SO4 2-), with 40 of the 43 lakes now showing steep declines in SO4 2- concentrations. The drop in SO4 2- was associated with a significant decrease in Ca2+ concentrations in 77% of the lakes (67% for Mg2+ concentrations). Overall, the acid-neutralizing capacity was increasing in 19 lakes and decreasing only in three, while 21 lakes showed no temporal trends. Compared with previous trend studies of the LRTAP-Québec network for the period of 1985–1993, the longer period (1985–1999) shows a clear improvement, with the proportion of lakes that were acidifying changing from 24 to 7% and with the proportion of lakes that were recovering changing from 16 to 35%. These observations suggest that the recent drop in SO4 2- deposition in the northeastern U.S. and eastern Canada was significant enough to allow chemical recovery for a significant proportion of Québec lakes. 相似文献
99.
100.
Alain Houle Colin A. Chapman William L. Vickery 《Behavioral ecology and sociobiology》2010,64(3):429-441
Recently, we demonstrated that the highest densities of fruit pulp are located in the uppermost zones of tree crowns. Since
heterogeneous distributions of depletable food is theorized to foster contest competition, we tested three hypotheses involving
rank differences among species of arboreal frugivores: (1) In the absence of competitors, species tend to feed in higher strata
of tree crowns; (2) interspecific contest competition occurs through monopolization and usurpation of feeding sites in these
higher strata; and (3) subordinate species decrease their feeding height and ingestion rate when dominants enter the food
patch. To test these hypotheses, we observed chimpanzees (Pan troglodytes), red-tailed monkeys (Cercopithecus ascanius), blue monkeys (Cercopithecus mitis), and gray-cheeked mangabeys (Lophocebus albigena) in Kibale National Park, Uganda. We found that: (1) all four primates fed preferentially in upper tree crowns when alone,
(2) dominant species monopolized and aggressively usurped the upper crown when co-feeding with subordinates and the latter
retreated below the middle of tree crowns, (3) in the presence of dominant species, subordinate species showed lower standardized
feeding height and modified their food intake rates, while dominants were not affected by the subordinate species, (4) subordinates
moved down at the arrival of and up at the departure of dominants, and (5) the presence of folivores in the tree did not affect
the feeding height of a frugivore, even through folivores were socially dominant. Contrary to expectations, we found that
red-tailed monkeys decreased their movements between successive fruits that they ate in the presence of blue monkeys compared
to when they were feeding alone, perhaps to avoid disturbing dominants and attracting aggression or because they ingested
more semi-ripe and green unripe fruits, i.e., more food of lower quality. 相似文献