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51.
Craig B. Stanford 《Behavioral ecology and sociobiology》1992,30(1):29-34
Summary Data from a 15-month field study of the capped langur monkey, Presbytis pileata, in Bangladesh indicate that allomothering behavior is restricted to particular female-infant dyads. Primary allomothers were all parous adult females; nulliparous females rarely allo-mothered, Newborn infants were transferred from the mother to other females within a short time of birth, as reported for some other colobine species, but over the first 3 months of life each neonate's contact with nonmothers was largely restricted to a single allomother in each of five study groups. Capped langur mothers with newborn infants spent more time feeding when the infant was being allomothered than when it was in the mother's care. The model of allomothering as a selfish behavior by nulliparous or pregnant females used to enhance maternal skills at the expense of mothers is not supported by this study. Rather, allomothering may have adaptive significance as altruistic behavior among group females, in that it enables lactating females to increase feeding time. Capped langur allomothering is best interpreted as a low-cost behavior that can benefit recipients that may or may not be related.
Offprint requests to the present address 相似文献
52.
Parental investment decision rules and the Concorde fallacy 总被引:4,自引:0,他引:4
Summary Investment theory states that animals should base their parental investment decisions on expected benefits, and not on whether or not past investment will be wasted. Otherwise, they would comnit the Concorde fallacy. If reproduction has a cost, however, then past investment and expected benefits are necessarily confounded. Assuming a cost of reproduction, animals will be selected to maximize their remaining lifetime reproductive success, subject to a tradeoff between present and future reproduction (Williams' principle). We extend Williams' principle and develop an experimental design that would allow past investment and expected benefits to be varied independently. This design illustrates the importance of the value of the brood relative to the value of future reproduction. 相似文献
53.
Katriina Tiira Anssi Laurila Katja Enberg Jorma Piironen Sami Aikio Esa Ranta Craig R. R. Primmer 《Behavioral ecology and sociobiology》2006,59(5):657-665
A key question of evolutionary importance is what factors influence who becomes dominant. Individual genetic variation has been found to be associated with several fitness traits, including behaviour. Could it also be a factor influencing social dominance? We investigated the association between social status and the amount of intra-individual genetic variation in juvenile brown trout (Salmo trutta). Genetic variation was estimated using 12 microsatellite loci. Dominant individuals had higher mean heterozygosity than subordinates in populations with the longest hatchery background. Heterozygosity–heterozygosity correlations did not find any evidence of inbreeding; however, single-locus analysis revealed four loci that each individually differed significantly between dominant and subordinate fish, thus giving more support to local than general effect as the mechanism behind the observed association between genetic diversity and a fitness-associated trait. We did not find any significant relation between mean d 2 and social status, or internal relatedness and social status. Our results suggest that individual genetic variation can influence dominance relations, but manifestation of this phenomenon may depend on the genetic background of the population. 相似文献
54.
The southern oyster drill, Stramonita (= Thais, Kool 1987) haemastoma, is a common intertidal and subtidal predator in the southeastern United States. It uses specialized feeding structures and
foraging strategies to bore holes through the shell of its bivalve prey. However, on the east coast of Florida, S. haemastoma, is common on sabellariid worm reefs constructed by the polychaete Phragmatopoma lapidosa (Walton Rocks Beach, Florida, 27°17′N, 80°12′W), a habitat where the snail’s typical prey are scarce. From 1999 to 2001,
we examined the feeding habits of S. haemastoma on sabellariid reefs and the behavioral and morphological responses of S. haemastoma that accompanied switching from a diet of bivalves to sabellariids. On worm reefs S. haemastoma feeds on P. lapidosa by inserting the proboscis deep into a worm’s tube. Worm-feeding snails had longer proboscises (~3.7 times shell height)
than bivalve-feeding conspecifics (~2.0 times shell height). Snails raised on different diets showed significant differences
in proboscis length suggesting that the proboscis length is phenotypically plastic. Whereas typical oyster drills must bore
holes for days before ingesting prey, S. haemastoma on worm reefs avoids boring and attacks and consumes worms in 15–50 min. In the laboratory, oyster drills consumed 1.7 worms
per day, spending <1 h each day feeding. On sabellariid reefs, differences in feeding, handling costs, and prey value, are
likely to have a significant effect on the ecology and life history of S. haemastoma in this habitat. 相似文献
55.
This article presents the results of demonstration of Geosafe Corporation's in-situ vitrification (ISV) technology at the Parsons Chemical/ETM Enterprises Superfund site in Grand Ledge, Michigan. The primary focus of this article is on the EPA's Superfund Innovative Technology Evaluation (SITE) Program assessment of the sixth melt. A total of eight melts were performed during this project. This demonstration was part of the SITE Program Demonstration (USEPA, 1994), which helped develop innovative hazardous waste treatment technologies, especially those offering permanent remedies for contaminated Superfund and other hazardous waste sites. The demonstration results are not only applicable to this particular project, but are also indicative of other Geosafe project experiences and demonstrate the current state of the ISV technology. The demonstration included two phases. In the first phase, the ISV technology was used to treat the Parsons contaminated soil. In the second phase, post-testing and analysis were conducted about one year after the ISV technology was applied to confirm that the vitrification was completed and that no contamination migration had occurred. 相似文献
56.
Richard A. Pircon MD Craig V. Towers Manuel Porto Stephen E. Gocke Thomas J. Garite 《黑龙江环境通报》1989,9(10):701-707
Fetal triploidy is commonly found in early pregnancy. The majority of these pregnancies spontaneously abort in the first trimester. Occasionally, the pregnancy progresses to the second and third trimesters. We reviewed the maternal serum alpha-fetoprotein (MSAFP), amniotic fluid alpha-fetoprotein (AFP), amniotic fluid acetylcholinesterase (ACHE), fetal pathology, and placental pathology in sex second-trimester pregnancies complicated by fetal triploidy. Four of these patients had MSAFP values greater than 7.5 multiples of the median (MoM). Five of six pregnancies had MSAFP values greater than 2.25 MoM. All five of these patients had a partial mole. Four patients had amniotic fluid AFP values greater than 2.0 MoM. Two fetuses had associated neural tube defects. These were the only patients with positive amniotic fluid ACHE. None of the other patients had fetuses with anomalies that are known to be associated with an elevated MSAFP. The elevated MSAFP appeared to be related to the presence of a partial mole. Two of the five cases with an MSAFP greater than 2.25 MoM did not have sonographic evidence of a significant anomaly. Therefore, karyotyping can be of benefit in evaluating patients with elevated MSAFP. 相似文献
57.
Use of X-ray absorption imaging to examine heterogeneous diffusion in fractured crystalline rocks 总被引:1,自引:0,他引:1
Altman SJ Uchida M Tidwell VC Boney CM Chambers BP 《Journal of contaminant hydrology》2004,69(1-2):1-26
Heterogeneous diffusion in different regions of a fractured granodiorite from Japan has been observed and measured through the use of X-ray absorption imaging. These regions include gouge-filled fractures, recrystallized fracture-filling material and hydrothermally altered matrix. With the X-ray absorption imaging technique, porosity, relative concentration, and relative mass of an iodine tracer were imaged in two dimensions with a sub-millimeter pixel size. Because portions of the samples analyzed have relatively low porosity values, imaging errors can potentially impact the results. For this reason, efforts were made to better understand and quantify this error. Based on the X-ray data, pore diffusion coefficients (Dp) for the different regions were estimated assuming a single diffusion rate and a lognormal multirate distribution of Dp. Results show Dp for the gouge-filled fractures are over an order of magnitude greater than those of the recrystallized fracture-filling material, which in turn is approximately two times greater than those for the altered matrix. The recrystallized fracture-filling material was found to exhibit the greatest degree of variability. The results of these experiments also provide evidence that diffusion from advective zones in fractures through the gouge-filled fractures and recrystallized fracture-filling material could increase the pore space available for matrix diffusion. This evidence is important for understanding the performance of potential nuclear waste repositories in crystalline rocks as diffusion is thought to be an important retardation mechanism for radionuclides. 相似文献
58.
59.
Polyacrylamide preparations for protection of water quality threatened by agricultural runoff contaminants 总被引:11,自引:0,他引:11
Entry JA Sojka RE Watwood M Ross C 《Environmental pollution (Barking, Essex : 1987)》2002,120(2):191-200
Waste streams associated with a variety of agricultural runoff sources are major contributors of nutrients, pesticides and enteric microorganisms to surface and ground waters. Water soluble anionic polyacrylamide (PAM) was found to be a highly effective erosion-preventing and infiltration-enhancing polymer, when applied at rates of 1-10 g m(-3) in furrow irrigation water. Water flowing from PAM treated irrigation furrows show large reductions in sediment, nutrients and pesticides. Recently PAM and PAM + CaO and PAM + Al(SO4)3 mixtures have been shown to filter bacteria, fungi and nutrients from animal wastewater. Low concentrations of PAM [175-350 g PAM ha(-1) as PAM or as PAM + CaO and PAM + Al(SO4) mixture] applied to the soil surface, resulted in dramatic decreases (10 fold) of total, coliform and fecal streptococci bacteria in cattle, fish and swine wastewater leachate and surface runoff. PAM treatment also filtered significant amounts of NH4, PO4 and total P in cattle and swine wastewater. This points to the potential of developing PAM as a water quality protection measure in combination with large-scale animal feeding operations. Potential benefits of PAM treatment of animal facility waste streams include: (1) low cost, (2) easy and quick application. (3) suitability for use with other pollution reduction techniques. Research on the efficacy of PAM for removal of protozoan parasites and viruses and more thorough assessment of PAM degradation in different soils is still needed to completely evaluate PAM treatment as an effective waste water treatment. We will present analysis and feasibility of using PAM, PAM + Al(SO4)3, and PAM + CaO application for specific applications. Our results demonstrate their potential efficacy in reducing sediment, nutrients and microorganisms from animal production facility effluents. 相似文献
60.
Foley TA Rendahl CS Kenski D 《Journal of the Air & Waste Management Association (1995)》2003,53(8):1003-1010
Reformulated gasoline (RFG) contains oxygen additives such as methyl tertiary butyl ether or ethanol. The additives enable vehicles to burn fuel with a higher air/fuel ratio, thereby lowering the emission of carbon monoxide (CO) and volatile organic compounds (VOCs). Because VOCs react with sunlight to form ozone (O3), the Clean Air Act requires severe O3 nonattainment areas such as southeastern Wisconsin to use RFG. On July 17, 2001, the U.S. Environmental Protection Agency (EPA) granted Milwaukee, WI, and Chicago, IL, a waiver from the VOC reduction requirement of Phase II RFG. The VOC reduction requirement was lowered from 27.4% of the 1990 baseline fuel to 25.4%. The assumption was that ethanol-blended RFG would lower summertime CO concentrations sufficiently to offset the increased VOC emissions. The waiver is estimated to increase VOC emissions by approximately 0.8%, or 0.4 t of VOC on a hot summer weekday. This study evaluates whether RFG has been effective in lowering southeastern Wisconsin ambient CO concentrations. Three years of ambient CO data before RFG was introduced were compared with the first three years of ambient CO data after RFG was introduced. This paper also evaluates how the meteorology, vehicle inspection/maintenance program, vehicle miles traveled, and stationary source emissions influence CO concentrations. The winter decrease in ambient CO concentrations was found to be statistically significant, while the summer data showed no statistically significant change, indicating that RFG is most effective lowering ambient CO concentrations in cold weather. 相似文献