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1.
Ecological opportunity is any change that allows populations to escape selection from competition and predation. After encountering ecological opportunity, populations may experience ecological release: enlarged population size, broadened resource use, and/or increased morphological variation. We identified ecological opportunity and tested for ecological release in three lizard colonists of White Sands, New Mexico (Sceloporus undulatus, Holbrookia maculata, and Aspidoscelis inornata). First, we provide evidence for ecological opportunity by demonstrating reduced species richness and abundance of potential competitors and predators at White Sands relative to nearby dark soils habitats. Second, we characterize ecological release at White Sands by demonstrating density compensation in the three White Sands lizard species and expanded resource use in White Sands S. undulatus. Contrary to predictions from ecological release models, we observed directional trait change but not increased trait variation in S. undulatus. Our results suggest that ecological opportunity and ecological release can be identified in natural populations, especially those that have recently colonized isolated ecosystems. 相似文献
2.
White Galloway cattle exhibit three different white coat colour phenotypes, that is, well marked, strongly marked and mismarked. However, mating of individuals with the preferred well or strongly marked phenotype also results in offspring with the undesired mismarked and/or even fully black coat colour. To elucidate the genetic background of the coat colour variations in White Galloway cattle, we analysed four coat colour relevant genes: mast/stem cell growth factor receptor ( KIT), KIT ligand ( KITLG), melanocortin 1 receptor ( MC1R) and tyrosinase ( TYR). Here, we show that the coat colour variations in White Galloway cattle and White Park cattle are caused by a KIT gene (chromosome 6) duplication and aberrant insertion on chromosome 29 (Cs 29) as recently described for colour‐sided Belgian Blue. Homozygous (Cs 29/Cs 29) White Galloway cattle and White Park cattle exhibit the mismarked phenotype, whereas heterozygous (Cs 29/wt 29) individuals are either well or strongly marked. In contrast, fully black individuals are characterised by the wild‐type chromosome 29. As known for other cattle breeds, mutations in the MC1R gene determine the red colouring. Our data suggest that the white coat colour variations in White Galloway cattle and White Park cattle are caused by a dose‐dependent effect based on the ploidy of aberrant insertions and inheritance of the KIT gene on chromosome 29. 相似文献
3.
The many contradictions in the anthropology of Leslie White derive mainly from the fact that he embraced two contradictory models of culture: the sui generis conception that he received from his Boasian education, and the materialist-utilitarian framework that developed out of his concern with cultural evolutionism. White never reconciled the two, but in any instance of conflict he gave preference to the sui generis, Boasian-derived conception. This led him eventually to repudiate significant aspects of his utilitarian-adaptive framework. 相似文献
4.
The purpose of this study was to compare two electron microscopy embedding media - LR White and Unicryl - with regard to cell morphologyical and immunohistochemical preservation properties for the study of fixation-sensitive nuclear antigens. Human cervical carcinoma (HeLa) cells were fixed with 2% paraformaldehyde and 0.1% glutaraldehyde, and embedded in parallel in the two resins: LR White and Unicryl using; two different polymerization protocols were used for each resin. Preservation of fine nuclear structure was good after LR White and poor after Unicryl embedding. Immunogold labeling of Sm antigen was significantly stronger on LR White sections. Polymerization by UV light resulted in stronger and more specific labeling than heat polymerization. These results show that LR White is advantageous over Unicryl for the study of nuclear antigens requiring delicate aldehyde fixation. 相似文献
5.
Making Meaning of Whiteness: Exploring Racial Identity with White Teachers. Alice Mclntyre. Albany: State University of New York Press, 1997. 193 pp. 相似文献
6.
There are extensive debates concerning the origin and the necessity of conservation of Pudong White pigs in the Taihu region of China. To elucidate their genetic ancestry, we sequenced the complete mtDNA D-loop sequences of 25 Pudong White pigs and 9 Shawutou pigs from the Taihu region and reanalyzed 158 published sequences of other breeds in GenBank. Haplotypes of all pigs were classified into two clades, A and E, but Pudong White pigs were found only in clade A. The results of population differentiation demonstrated that there were few genetic exchanges among the eight populations. Furthermore, divergence time estimates suggested that the Pudong White pigs split from four types of Taihu pigs at about 0.26–0.75 million years ago. Overall, the results suggest that the Pudong White pig is a unique population, and conservation practice should concentrate on preserving this isolated population. 相似文献
7.
The genotypes of growth hormone gene polymorphisms (GH-DdeI, GH-MspI, GH-HaeII, GH-ApaI, GH-CfoI) were determined in 78 pigs [Czech Large White sires (CLWsire line) x Polish Large White (PLW) sows, Polish Large White sires x Polish Large White sows], by the PCR-RFLP method. Preliminary studies found only GH DdeI polymorphism to be associated with performance traits. The associations of this polymorphism with growth and carcass traits were investigated. The linear model included the effects of candidate genes, genetic groups, sex and linear covariables of age at slaughter and body weight at weaning. The DdeI polymorphism of the GH gene showed associations with carcass length (P 相似文献
8.
Eleven species of White Sea invertebrates (sponges, actinians, hydroids, polychaetes, and nudibranch mollusks) were tested for the presence of associated oxygen-evolving phototrophic microorganisms (OPM) (microalgae and cyanobacteria). Two main approaches were applied: (a) light and electron microscopy of intact samples and fixed preparations of invertebrates, and (b) isolation of microorganisms from samples of invertebrates after mild surface sterilization. The obtained results lead to conclusions on the formation of multicomponent associations by White Sea invertebrates and OPM based on the following data: (1) isolation of 27 cultures of OPM from eight species of invertebrates (sponges, hydroids, polychaete trochophore larva), (2) specificity of association between epibiontic communities of microorganisms and macroorganisms within the same biotope, and (3) spatial integration of micro- and macropartners resulting in the formation of morphological structures within the interorganismic contact zones. 相似文献
9.
Capsule Accessing extra food from waste dumps increases egg volume and hatching mass in White Storks. Aim To test how White Storks vary their investment in egg size, especially in last laid eggs, in relation to food availability, and to improve our understanding of the importance of extra feeding on intra-clutch variation. Methods The study was carried out in three White Stork breeding colonies in northern Algeria. Breeding performance was recorded in 70 nests over three years. White Stork colonies situated close to chicken farms were considered to be part of a ‘pseudo experiment’ where parents had access to extra food. Egg volume, laying order, hatching order and hatching weight were recorded. Results Egg volume and hatching mass in White Storks was significantly greater when they had access to extra food. The reproductive value of last laid eggs (fourth and fifth) doubled when females had access to extra food. Conclusion Laying smaller last eggs within a clutch provides a mechanism to facilitate early brood reduction in the White Stork, and so should be advantageous when food is scarce. On the contrary, when females had access to extra food, last laid eggs were as big as first eggs which suggests egg size variation is adaptable to local conditions. 相似文献
10.
White Saris and Sweet Mangoes: Aging, Gender, and Body in North India. Sarah Lamb. Berkeley: University of California Press, 2000. 306 pp. 相似文献
11.
We studied the following growth indices of the White Sea mussels Mytilus edulis: shell length, total weight, soft tissue weight, and shell weight. The coefficients of allometric relationships between the indices were determined. Age-related changes in the indices could be approximated by the Bertalanffy equation. The maximum age of mollusks in the studied population equaled 13 years (with the maximum shell length of 66.2 mm). Growth rate of littoral mussels in the region of Umba Settlement (Northern Kandalaksha Bay) was lower as compared to those published for other littoral White Sea populations (Chupa Bay). 相似文献
12.
The literature and original data on the primary production of phytoplankton in the White Sea are analyzed. By this parameter, the White Sea is significantly inferior only to the Chukchi Sea; it is similar to the Barents Sea, and exceeds other Russian Arctic seas by two to three times (the Kara Sea, Laptev Sea, and East Siberian Sea). 相似文献
14.
Beyond Black and White: New Faces and Voices in U.S. Schools. Maxine Seller and Lois Weis, eds. Albany: State University of New York Press, 1997. 328 pp. 相似文献
15.
White Saris and Sweet Mangoes: Aging, Gender, and the Body in North India. Sarah Lamb. Berkeley: University of California Press, 2000. xvii. 306 pp. 相似文献
16.
“As the 21st century quickly approaches with an expansive geriatric population growth, are we adequately preparing health professionals to address patient needs? Will there be a shortage of competent clinicians and proficient faculty? Is there a proposed agenda to improve educational outcomes, clinical expertise, and oral health status of older adults? These and related concerns have prompted a focused geriatric education project within the United States. The Bureau of Health Professions (BHPr) of the Health Resources and Services Administration has provided the impetus and leadership through the Geriatric Education Futures Project. Dentistry is one of eleven disciplines invited to participate in this important effort which also includes medicine, nursing, social work, public health, allied and associated health, managed care, long-term care, case management, interdisciplinary education, and ethnogeriatrics. The first two phases of this project were: 1) writing White Papers which give “a critical review of the state of the art of geriatric education, project a future response to societal need and provide policy recommendations to achieve the preferred future;” and 2) sponsoring an invitational National Forum on Geriatric Education and Training in the spring of 1995 to present, discuss, and accept the White Paper findings, as well as enlisting broader participation and support from appropriate educational institutions, professional organizations (including the American Society for Geriatric Dentistry and the American Dental Association), government agencies, foundations, consumer organisations, etc. The third phase is ongoing and includes the development of national innovative educational collaboratives, dissemination of the White Papers and related documents, and continued “catalytic activities directed toward the implementation of a national agenda for action in geriatric education.” The complete text of all discipline-specific White Papers can be found in A National Agenda for Geriatric Education, Volume 1: White Papers1. In an effort to more extensively disseminate the findings from the Dentistry White Paper, Gerodontology is reprinting the first two-thirds of the Dentistry White Paper which includes the state of the art in geriatric dental education and future vision needed to meet the needs of older adults, as well as summary identification of the 19 dental policy recommendations (See Table 3). Special Care in Dentistry2 has recently published the complete text of these specific recommendations including the rationale, action required, responsible agents, and expected outcomes. Although some information contained in this White Paper may be specific only to the United States, it is also apparent that much of its content has relevance to gerodontology efforts in industrialised countries throughout the world.”– Bernice A. Parlak and Susan M. Klein (see endnote) 相似文献
17.
Healthy individuals in the United States identified as having Black race have lower neutrophil counts, on average, than individuals identified as having White race, which could result in more negative diagnostic evaluations for neutropenia. To test this hypothesis, the proportion of evaluations where the final diagnosis was clinically insignificant neutropenia for Black and White individuals who underwent an evaluation by a haematologist that included a bone marrow (BM) biopsy to investigate neutropenia was assessed. 172 individuals without prior haematological diagnoses who underwent a haematological evaluation to investigate neutropenia. Individuals diagnosed with clinically insignificant neutropenia between Black and White individuals were compared using a propensity‐score‐adjusted logistic regression. Of 172 individuals, 42 (24%) were classified as Black race, 86 (50%) were males, and the 79 (46%) were over 18 years old. A BM biopsy did not identify pathology in 95% (40 of 42) of Black individuals and 68% (89 of 130) of White Individuals. Black individuals (25 of 42 [60%]) received a final diagnosis of clinically insignificant neutropenia, compared to White individuals (12 of 130 [9%]) (adjusted odds ratio =7.9, 95% CI: 3.1 – 21.1). We conclude that black individuals were more likely to receive a diagnosis of clinically insignificant neutropenia after haematological assessment. 相似文献
18.
On the basis of an ichthyoplankton survey made in July 2003 in Kandalaskha Gulf, the Basin, the Gorlo Strait, and the Voronka the species composition and distribution of fish eggs and larvae are investigated. The ichtyoplankton comprises 17 fish species, of which the majority (11) were boreal forms. Other fish were represented by arctic species (2) and arctic-boreal species (4). The traits of distribution of abundantly caught species are considered in detail: larvae of the White Sea oligovertebrate herring Clupea pallasii marisabli, eggs of the dab Limanda limanda, larvae of the northern sand lance Ammodytes marinus, and of the capelin Mallotus villosus villosus. The presence of all larvae of White Sea herring only within Kandalaskha Gulf is considered to be evidence supporting the hypothesis suggested by Dmitriev (1946) on the absence of their drift beyond large gulfs of the White Sea. The natural barrier for mutual exchange with early developmental stages of fish between the White Sea and the Barents Sea in summer may be a developed hydrologic front in the boundary area of the Basin and Gorlo Strait, discovered in the course of the survey. This front causes their death by thermohaline shock in the abrupt gradient zone. 相似文献
19.
White rhinoceros range size was ascertained telemetrically in the south-western Kruger National Park. The mean annual range size of territorial males was 9.86 km 2 compared to 22.83 km 2 for adult females. White rhinoceros females' summer wet season range was larger (21.44 km 2) than the winter dry season range (11.64 km 2). It is argued that abundant field-water during the wet season enables animals to range further from permanent water supplies and to utilize larger foraging areas. White rhinoceros have core areas in their individual ranges that usually are situated along riverbanks in the preferred grazing regions. These core areas also include some favourite resting spots on high-lying areas. White rhinoceros range sizes in the south-western Kruger National Park were similar to those of other reserves with comparable white rhinoceros densities. In the Umfolozi Game Reserve, which has a higher white rhinoceros density than the Kruger National Park, the individual ranges are much smaller. 相似文献
20.
The Great White Pelican Pelecanus anocrotalus is the largest migrating bird in Israel and is an endangered species. The Palearctic populations of the Great White Pelican breed in eastern Europe and Asia and most of them pass through the ‘bottleneck’ of Israel to wintering grounds in Africa. Natural feeding sites for pelicans have diminished during recent decades due to human activities, and sites of extensive aquaculture have become the favourite feeding places for wintering and migrating Great White Pelicans. The fish industry has reported a significant impact on fish yield and the conflict between pelicans and fishermen has escalated so that hundreds of pelicans have died in recent years from shooting or accidental electrocution. We approached this management problem by studying the energy requirements of the Great White Pelican during migration and while wintering in Israel, under different feeding regimes (fish or chicks) and in different seasons, in captivity. The results show that a captive bird consumes 1.1 kg of fish per day. The basal metabolic rate and apparent metabolized energy of the Great White Pelican are both higher than predicted from allometric equations. Energetic demands were quite stable on both diets (fish and chicks) and during both seasons (winter and summer). The fat deposits of migrating pelicans averaged 313.5 g compared with 480 g in wintering birds (3.4% and 5.4% of body mass, respectively). Based on these fat contents and on the measured daily energy consumption, we calculated that birds that do not feed in Israel can fly only up to 1620 km from Israel southward and could not cover the distance to their likely wintering grounds in the Sudd area in southern Sudan. However, birds that replenish their fuel reserves could fly up to 2460 km and hence could reach this area. Therefore, we conclude that Great White Pelicans must feed in Israel during the autumn migration in order to complete their journey to Africa. One solution to the conflict between pelicans and fishermen could be to combine deterrents preventing pelicans from feeding in fish‐ponds with the provision of attractive alternative reservoirs, to ensure regular food supplies during autumn. 相似文献
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