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671.
Joan B. Silk Jeanne Altmann Susan C. Alberts 《Behavioral ecology and sociobiology》2006,61(2):183-195
Sociality has positive effects on female fitness in many mammalian species. Among female baboons, those who are most socially integrated reproduce most successfully. Here we test a number of predictions derived from kin selection theory about the strength of social bonds among adult female baboons. Our analyses are based on systematic observations of grooming and association patterns among 118 females living in seven different social groups in the Amboseli Basin of Kenya over a 16-year period. Females in these groups formed the strongest bonds with close kin, including their mothers, daughters, and maternal and paternal sisters. Females were also strongly attracted toward females who were close to their own age, perhaps because peers were often paternal sisters. Females’ bonds with their maternal sisters were strengthened after their mother’s deaths, whereas their relationships with their maternal aunts were weakened after their mother’s death. In addition, females formed stronger bonds with their paternal sisters when no close maternal kin were available, and they compensated for the absence of any close kin by forming strong bonds with nonrelatives. Taken together, these data suggest that social bonds play a vital role in females’ lives, and the ability to establish and maintain strong social bonds may have important fitness consequences for females.Joan B. Silk is on sabbatical at Cambridge University from September 2005 to August 2006. Tel.: +44-7929759697; Fax: +44-1223-335460. 相似文献
672.
Susan M. Haig Jeffrey R. Walters Jonathan H. Plissner 《Behavioral ecology and sociobiology》1994,34(4):295-303
We examined the genetic relationship among putative parents, offspring, and helpers in 224 red-cock-aded woodpeckers (Picoides borealis) from the Sandhills of North Carolina. Comparison of DNA similarity with a pedigree constructed from 3,823 individually-marked birds observed from 1979 to 1992 provided verification of observed relatedness in the sampled population (R
2 = 0.87, df = 14, P < 0.001). In this population, breeding pairs may or may not have helpers, most of which are males that remain on their natal territory. Our sample included helpers assisting their parents, helpers assisting a related male and an unrelated female, and helpers assisting an unrelated pair. Band by band comparison and examination of similarity among DNA profiles indicated that all offspring from non-helped nests were sired by their putative parents (n = 28 families). Similarly, all but one offspring in helped nests were also sired by their putative parents (n = 16 families). In the exceptional case, the offspring evidently was sired by a male external to the group. Analysis of similarity values supported the conclusion that matings by helpers or extra-group males are rare or non-existent. Our results indicate that in this species advantages gained by individuals remaining on their natal territories as helpers do not generally include siring offspring.
Correspondence to: S. Haig 相似文献
673.
Toward Conservation of Midcontinental Shorebird Migrations 总被引:1,自引:0,他引:1
Shorebirds represent a highly diverse group of species, many of which experience tremendous energy demands associated with long-distance migratory flights. Transcontinental migrants are dependent upon dynamic freshwater wetlands for stopover resources essential for replenishment of lipid reserves and completion of migration. Patterns of shorebird migration across midcontinental wetlands were detected from migration reports to American Birds and information provided by U.S. Fish and Wildlife Service national wildlife refuges. Patterns in species composition and abundance varied geographically, emphasizing the uniqueness of different regions to migrating shorebirds. Smaller species and neotropical migrants moved primarily across the Great Plains, whereas larger species and North American migrants predominated in assemblages in the intermountain west Shorebirds were broadly dispersed in wetland habitats with dynamic water regimes. Whereas populations of shorebirds in coastal systems appear to concentrate at sites of seasonally predictable and abundant food resources, we propose that transcontinental shorebirds disperse and use wetlands opportunistically. This migration system exemplifies the need for large-scale, coordinated regional management efforts that recognize the dynamic nature of ecosystem processes. 相似文献
674.
Anthony Johnson F. Susan Cowchock Marilyn Darby Ronald Wapner Laird G. Jackson 《黑龙江环境通报》1991,11(7):443-450
First-trimester maternal serum alpha-fetoprotein (AFP) and human chorionic gonadotropin (HCG) levels were measured in samples from 29 women with cytogenetically abnormal pregnancies and 145 women with cytogenetically normal pregnancies matched for gestational age, race, and sample storage time. All patients had a risk of fetal aneuploidy greater than or equal to that of a mother 35 years of age. AFP was significantly lower in samples from pregnancies affected with trisomy 21 (0.67 MoM;p <0.05), while HCG values were no different from those of matched controls. Trisomies 13 and 18 could not be distinguished from matched controls by AFP. However, levels of HCG were significantly lower in such pregnancy samples, with median values of 0.65 MoM in trisomy 13 and 0.32 MoM in trisomy 18 (p<0.05). Variations in AFP and HCG levels suggest that expressed differences between autosomal aneuploidies include differences in fetal and placenta! protein production in the first trimester. 相似文献
675.
Sujit Das T. Randall Curlee Colleen G. Rizy Susan M. Schexnayder 《Resources, Conservation and Recycling》1995,14(3-4)
Changes in the trends in the material composition of domestic and imported automobiles and the increasing cost of landfilling the non-recyclable portion of automobiles (automobile shredder residue or ASR) pose questions about the future of automobile recycling in the United States. In response to these challenges, new and innovative approaches to automobile recycling are being developed. This paper presents the findings of a recent study to examine the impacts of these changes on the life cycle energy consumption of automobiles and on the quantity of waste that must be disposed of. Given the recycle status quo, trends in material composition and the viability of recycling the non-metallic components of the typical automobile are of secondary importance when compared to the energy consumed during the life of the automobile. The energy savings resulting from small changes in the fuel efficiency of a vehicle overshadow potential energy losses associated with the adoption of new and possibly non-recyclable materials. Under status quo conditions, the life cycle energy consumed by the typical automobile is projected to decrease from 599 million Btus in 1992 to 565 million Btus in 2000. Energy consumed during the manufacture of the typical car will increase from about 120 to 140 million Btus between 1992 and 2000, while energy used during vehicle operation will decrease from 520 to 480 million Btus. This study projects that energy saved at the recycle step will increase from 41 million Btus in 1992 to 55 million Btus in 2000. This study also investigated the energy impacts of several potential changes to the recycle status quo, including the adoption of technologies to retrieve the heat value of ASR by incineration and the recycle of some or all thermoplastics in the typical automobile. The study estimates that under optimistic conditions —i.e., the recycling of all thermoplastics and the incineration with heat recovery of all remaining ASR —about 8 million Btus could be saved per automobile —i.e., an increase from about 55 to 63 million Btus. In the more realistic scenario —i.e., the recycling of easy-to-remove thermoplastic components (bumper covers and dash-boards) —the potential energy savings are about 1 million Btus per vehicle. It is estimated that the annual quantity of ASR in the United States could be reduced from about 5 billion pounds to as little as 1 billion pounds of ash if all ASR is incinerated. Alternatively, ASR quantity could be reduced to about 4 billion pounds if all thermoplastics in automobiles are recycled. However, in the case of recycling only thermoplastic bumper covers and dashboards, the quantity of ASR would be reduced by only 0.2 billion pounds. A significant reduction or increase in the size of the ASR waste stream will not in itself have a large impact on the solid waste stream in the United States. 相似文献
676.
Evaluation model for developing,implementing, and assessing conservation education programs: Examples from Belize and Costa Rica 总被引:1,自引:0,他引:1
Susan K. Jacobson 《Environmental management》1991,15(2):143-150
Evaluation of conservation education programs can: (1) provide accountability in demonstrating a program's worth, (2) offer
an opportunity for receiving feedback and improving programs, (3) further our understanding of the process of program development,
and (4) promote conservation education by substantiating claims about its benefits. The Planning-Process-Product systems evaluation
model provides feedback needed for making decisions about the development, implementation, and outcome of a program. Planning
evaluation was useful in assessing the needs, goals, opportunities, and constraints of a number of programs in Costa Rica
and Belize, such as a forestry education project and a zoo outreach program. It provided a basis for making planning decisions
incorporating specific objectives, such as the reforestation of a region or a change in knowledge and attitudes in program
participants. Process evaluation provided a Costa Rican sustainable development program with feedback during its implementation
and enabled it to modify and improve its newsletter for local farmers and its ecology classes for school children. Product
evaluation assessed project accomplishments, such as the $700,000 raised by the Children's Rainforest group and the 20 miles
of riparian land under conservation management as part of the Belize Community Baboon Sanctuary project. Outcomes are compared
with the programs original monetary or land management objectives to determine the success of the programs and to provide
feedback for improvement. 相似文献
677.
678.
A review of wetland impacts authorized under the New Jersey Freshwater Wetlands Protection Act (FWPA) was conducted based on permitting data compiled for the period 1 July 1988 to 31 December 1993. Data regarding the acreage of wetlands impacted, location of impacts by drainage basin and watershed, and mitigation were analyzed. Wetland impacts authorized and mitigation under New Jersey's program were evaluated and compared with Section 404 information available for New Jersey and other regions of the United States.Under the FWPA, 3003 permits were issued authorizing impacts to 234.76 ha (602.27 acres) of wetlands and waters. Compensatory mitigation requirements for impacts associated with individual permits required the creation of 69.20 ha. (171.00 acres), and restoration of 16.49 ha (40.75 acres) of wetlands. Cumulative impacts by watershed were directly related to levels of development and population growth.The FWPA has resulted in an estimated 67% reduction [44.32 ha (109.47 acres) vs 136.26 ha (336.56 acres)] in annual wetland and water impacts when compared with Section 404 data for New Jersey. For mitigation, the slight increase in wetland acreage over acreage impacted is largely consistent with Section 404 data.Based on this evaluation, the FWPA has succeeded in reducing the level of wetland impacts in New Jersey. However, despite stringent regulation of activities in and around wetlands, New Jersey continues to experience approximately 32 ha (79 acres) of unmitigated wetland impacts annually. Our results suggest that additional efforts focusing on minimizing wetland impacts and increasing wetlands creation are needed to attain a goal of no net loss of freshwater wetlands. 相似文献
679.
Based on intergroup theory, this study examined relationships among group characteristics (racioethnicity, gender, and level), contextual organizational unit characteristics (gender and racioethnic heterogeneity, resource support for women and racioethnic minorities) and perceptions of diversity climate by faculty at a large university. Compared to white men, white women and racioethnic minorities placed greater value on employer efforts to promote diversity, and held more favorable attitudes about the qualifications of women and racioethnic minorities. The study found that group rather than contextual organizational unit characteristics were more strongly related to diversity climate. However, the organizational unit characteristic, gender heterogeneity, was significantly related to valuing diversity. The greater the ratio of women in a unit, regardless of the respondents' gender, racioethnicity or level, the more favorable diversity activities were viewed. In addition, units whose allocation of resources to racioethnic minorities were perceived as insufficient by respondents were more likely to have members who valued diversity and held favorable perceptions toward the qualifications of racioethnic minorities. Implications for organizations and future research are offered. 相似文献
680.
Susan Rose-Ackerman 《Journal of Environmental Economics and Management》1977,4(2):167-184
Many public programs have differential impacts on diverse parts of metropolitan areas. This fact has led analysts to use changes in land values as measures of the benefits of public programs. Using a model derived from theoretical urban economics, this paper demonstrates that changes in land values will only equal total benefits under very restrictive assumptions. Making concrete assumptions about consumer demand, the paper goes beyond previous work to consider the distributional impact of three different kinds of public programs: those which provide uniform benefits to every community, those which attempt to reduce intercommunity inequality, and those which generate improvements in only a subset of the region's towns. 相似文献