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701.
B. N. Lohani Pakorn Adulbhan 《Journal of the American Water Resources Association》1979,15(4):1028-1038
ABSTRACT: Linear programming is the simplest of all the optimization techniques used in regional water quality management studies; but the technique can optimize only one goal. When there are multiple goals with the same or different priorities, goal programming is a useful decisionmaking tool. This paper illustrates the application of goal programming to a regional water quality management problem where the following two goals are considered: (1) minimize the total cost of waste treatment, and (2) maintain the water quality goals (dissolved oxygen) close to the minimum level stated in the stream standards. 相似文献
702.
Ian C. Gilby Lauren J. N. Brent Emily E. Wroblewski Rebecca S. Rudicell Beatrice H. Hahn Jane Goodall Anne E. Pusey 《Behavioral ecology and sociobiology》2013,67(3):373-381
Coalitionary aggression occurs when at least two individuals jointly direct aggression at one or more conspecific targets. Scientists have long argued that this common form of cooperation has positive fitness consequences. Nevertheless, despite evidence that social bond strength (which is thought to promote coalition formation) is correlated with fitness in primates, cetaceans, and ungulates, few studies have directly examined whether coalitionary aggression improves reproductive success. We tested the hypothesis that among free-ranging chimpanzees (Pan troglodytes schweinfurthii), participation in coalitionary aggression increases reproductive output. Using 14 years of genetic and behavioral data from Gombe National Park, Tanzania, we found that coalitionary aggression increased a male’s chances of (A) siring offspring, compared to other males of similar dominance rank, and (B) ascending in rank, a correlate of future reproductive output. Because male chimpanzees form coalitions with many others within a complex network, we used social network analysis to identify the types of connections correlated with these fitness benefits. The beneficiaries of coalitionary aggression were males with the highest “betweenness”—that is, those who tended to have coalition partners who themselves did not form coalitions with each other. This suggests that beyond simply recognizing third-party relationships, chimpanzees may use this knowledge to choose coalition partners. If so, this is a significant step forward in our knowledge of the adaptive value of social intelligence. Regardless of mechanism, however, this is the first evidence of genetic benefits of coalitionary aggression in this species, and therefore has important implications for understanding the evolution of cooperation. 相似文献
703.
Christopher N. Templeton ?a?lar Ak?ay S. Elizabeth Campbell Michael D. Beecher 《Behavioral ecology and sociobiology》2012,66(11):1503-1509
Animals frequently use signals to modulate aggressive interactions. Establishing that a signal is aggressive or threatening requires demonstrating that it is more commonly used in agonistic contexts, that it predicts subsequent aggressive behaviors by the sender, and that receivers respond differently to this signal. Like many birds, song sparrows (Melospiza melodia) produce a low-amplitude “soft song” vocalization that has been hypothesized to be an aggressive signal. Soft song meets the first two criteria, but previous research has failed to demonstrate that soft song provokes aggression or that receivers even perceive soft song differently from normal loud song. We used a playback experiment with taxidermic mount presentation to test whether territorial male song sparrows respond differently to loud and soft song playbacks. Subjects reacted more strongly to the soft song playback by approaching the mount more closely, increasing wing wave displays, and increasing the proportion of their own songs that were soft songs, with further trends toward increasing the number of flights and attacks. These results confirm that soft song is a conventional signal of aggression in song sparrows and that increased receiver retaliation maintains its reliability. 相似文献
704.
Miguel Costa Leal Patricia N. Pochelon Teresa Lopes da Silva Alberto Reis Rui Rosa Ricardo Calado 《Marine Biology》2013,160(4):763-772
Offspring quality of decapod crustaceans has been widely studied, with special emphasis on the sources of variability determining embryonic and larval quality. Nevertheless, maternal provisioning has commonly been overlooked as a potential source of offspring within-brood variability. In the present study, the existence of variable maternal provisioning was assessed through the analysis of the fatty acid (FA) profile of newly extruded embryos from different regions of the brooding chamber of Homarus gammarus. Significant differences in the FA profile of embryos sampled from different pleopods and sides of the brooding chamber were recorded. Significant deviations of the overall mean of each surveyed female were also observed for essential FA, particularly 20:4n-6, 20:5n-3 and 22:6n-3. Lipid energy available to fuel embryogenesis also varied among embryos sampled from different regions of the brooding chamber. Results suggest variable female investment at oocyte production, which may be amplified during the incubation period of developing embryos by differential lipid catabolism. For the first time, maternal provisioning is evidenced as an additional source for within-brood variability in the FA profile of embryos. 相似文献
705.
Aaron N. Rice 《Marine Biology》2008,154(2):255-267
Fish feeding behavior results from successful coordination of the fins, jaws, and sensory systems, and the organization of
this behavior may affect the fish’s foraging abilities and trophic ecology. Using quantitative kinematic methods, movements
of the jaws, fins and eyes of Tautoga onitis (Teleostei: Labridae) were analyzed during feeding events. Tautog feeding events consisted of three phases: approach, strike,
and recovery, each defined by a combination of kinematic events. The approach was characterized by changes in fin movements
and in body position, with the eyes directed forward at the food item. The strike began with the onset of jaw opening and
protrusion, then cranial elevation, with the eyes no longer looking at the food item. The end of the strike and the beginning
of the recovery involved a braking maneuver with the pectoral fins; the fish turns and swims away from the original food location
item after prey capture. The coordination performance variables of tautog were quantitatively compared to published data from
closely related cheiline wrasses and parrotfishes, which represent different feeding ecologies within a monophyletic assemblage.
Fishes feeding on molluscs and benthic invertebrates (Cheilinus fasciatus and Tautoga onitis) represented an intermediate coordination condition, with herbivores (the parrotfishes, Scarus quoyi and Sparisoma radians) at one extreme, and fishes feeding on elusive prey (Epibulus insidiator and Oxycheilinus digrammus) at the other extreme. The analysis suggests that the biomechanical demands of coordination for feeding on benthic invertebrates
may represent a generalized, and perhaps ancestral behavior in the wrasses, whereas more specialized trophic niches have evolved
divergent, more specialized demands. Examining the movement and coordination of the jaws, fins, and eyes during fish feeding
provides a detailed mechanistic basis for behavior, and comparison of coordination patterns during feeding among different
taxa can measure how these trophic strategies differ. Understanding the evolution of feeding ecologies in these demersal fishes
may have implications for understanding their role within their shallow water reef community. 相似文献
706.
707.
Inbreeding Depression, Environmental Stress, and Population Size Variation in Scarlet Gilia (Ipomopsis aggregata) 总被引:5,自引:0,他引:5
Despite a large body of theory, few studies have directly assessed the effects of variation in population size on fitness components in natural populations of plants. We conducted studies on 10 populations of scarlet gilia, Ipomopsis aggregata , to assess the effects of population size and year-to-year variation in size on the relative fitness of plants. We showed that seed size and germination success are significantly reduced in small populations (those 100 flowering plants) of scarlet gilia. Plants from small populations are also more susceptible to environmental stress. When plants from small and large populations were subjected to an imposed stress (combined effects of transplanting and experimental clipping, simulating ungulate herbivory) in a common garden experiment, plants from small populations suffered higher mortality and were ultimately of smaller size than plants from large populations. In addition, experimental evidence indicates that observed fitness reductions are genetic, due to the effects of genetic drift and/or inbreeding depression. When pollen was introduced from distant populations into two small populations, seed mass and percentage of germination were bolstered, while pollen transferred into a large population had no significant effect. Year-to-year variation in population size and its effects on plant fitness are also discussed. In one small population, for example, a substantial increase in size from within did not introduce sufficient new (archived) genetic material to fully overcome the effects of inbreeding depression. 相似文献
708.
Singh VK Pathak MK Bihari V Jyoti Patel DK Mathur N Kesavachandran CN Siddiqui MK 《Journal of environmental biology / Academy of Environmental Biology, India》2011,32(1):39-42
An important role of oxidative stress for the development of vascular and neurological complications has encouraged us to undertake a study to assess the oxidative stress induced nerve conduction deficits among cigarette smokers. Eighteen regular male cigarette smokers and twenty nine male non-smokers were diagnosed for clinical neuro-physiological tests viz., motor and sensory nerve conduction velocity (MNCV and SNCV) and redox status. Significant depletion of reduced glutathione (GSH) level (p < 0.05) and significant increase in malondialdehyde (MDA) level (p < 0.01) was found in smokers compared to non-smokers. Motor and sensory nerve conduction velocity showed no significant difference among smokers compared to non-smokers. The present study shows that smoking can induce oxidative stress among smokers but could not exacerbate to nerve conduction deficits. 相似文献
709.
710.
P. M. Lutz Selena Bauer N. L. Gale J. Hewett P. E. Phillips F. M. Looney H. Bengsch 《Environmental geochemistry and health》1994,16(3-4):179-189
Lead has been found to depress the immune system in animal studies at levels far below those responsible for overt toxicity. Literature studies in animal systems most clearly showed an effect of lead on response to a specific immunogenic stimulus. Data are sparse concerning the effects of lead on the immune system in the human population at greatest risk for exposure-children up to six years of age. This portion of the Phase I study reports concentrations of IgG, IgM, IgA, and IgE, as well as antibody titers to the specific antigenic stimuli provided by the vaccines against diphtheria, tetanus, and Rubella. The study population consisted of a group of 193 children, ages 9 months to 6 years, who participate in the WIC (Women, Infants and Children) and Lead Poisoning Prevention Programs in the urban area of Springfield-Greene County Missouri. Blood lead levels ranged from 1 to 50 g dL–1. Total Ig levels were determined and the data were analysed. No consistent significant differences were observed among the risk categories in the five age groups examined. A single Ig class in each of three age groups showed apparent significant differences among the various risk categories, but these differences were not correlated with blood lead. An analysis of specific antibody titers to diphtheria, tetanus, and Rubella was performed. Regression analyses of current data in Phase I of this study suggest a detrimental effect of lead on the antibody titres to diphtheria and Rubella. 相似文献