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The cranial morphology of Early Holocene American human samples is characterized by a long and narrow cranial vault, whereas more recent samples exhibit a shorter and wider cranial vault. Two hypotheses have been proposed to account for the morphological differences between early and late‐American samples: (a) the migratory hypothesis that suggests that the morphological variation between early and late American samples was the result of a variable number of migratory waves; and (b) the local diversification hypothesis, that is, the morphological differences between early and late American samples were mainly generated by local, random (genetic drift), and nonrandom factors (selection and phenotypic plasticity). We present the first craniometric study of three early skulls from the Argentinean Pampas, dated ~8,000 cal. years BP (Arroyo Seco 2, Chocorí, and La Tigra), and one associated with mega‐faunal remains (Fontezuelas skull). In addition, we studied several Late Holocene samples. We show that the skulls from the Argentinean Pampas are morphologically similar to other Early Holocene American skulls (i.e., Lagoa Santa from Brazil, Tequendama, Checua, and Aguazuque from Colombia, Lauricocha from Peru, and early Mexicans) that exhibit long and narrow cranial vaults. These samples differ from the Late Holocene American samples that exhibit a shorter and wider cranial vault. Our results underscore the important differences in cranial morphology between early and late‐American samples. However, we emphasize the need for further studies to discuss alternative hypotheses regarding such differences. Am J Phys Anthropol 143:298–305, 2010. © 2010 Wiley‐Liss, Inc.  相似文献   

3.
Genetic influences on alcohol and drug dependence partially overlap, however, specific loci underlying this overlap remain unclear. We conducted a genome‐wide association study (GWAS) of a phenotype representing alcohol or illicit drug dependence (ANYDEP) among 7291 European‐Americans (EA; 2927 cases) and 3132 African‐Americans (AA: 1315 cases) participating in the family‐based Collaborative Study on the Genetics of Alcoholism. ANYDEP was heritable (h 2 in EA = 0.60, AA = 0.37). The AA GWAS identified three regions with genome‐wide significant (GWS; P < 5E‐08) single nucleotide polymorphisms (SNPs) on chromosomes 3 (rs34066662, rs58801820) and 13 (rs75168521, rs78886294), and an insertion‐deletion on chromosome 5 (chr5:141988181). No polymorphisms reached GWS in the EA. One GWS region (chromosome 1: rs1890881) emerged from a trans‐ancestral meta‐analysis (EA + AA) of ANYDEP, and was attributable to alcohol dependence in both samples. Four genes (AA: CRKL, DZIP3, SBK3; EA: P2RX6) and four sets of genes were significantly enriched within biological pathways for hemostasis and signal transduction. GWS signals did not replicate in two independent samples but there was weak evidence for association between rs1890881 and alcohol intake in the UK Biobank. Among 118 AA and 481 EA individuals from the Duke Neurogenetics Study, rs75168521 and rs1890881 genotypes were associated with variability in reward‐related ventral striatum activation. This study identified novel loci for substance dependence and provides preliminary evidence that these variants are also associated with individual differences in neural reward reactivity. Gene discovery efforts in non‐European samples with distinct patterns of substance use may lead to the identification of novel ancestry‐specific genetic markers of risk.  相似文献   

4.
Objective: A randomized controlled trial tested the efficacy of an internet‐based lifestyle behavior modification program for African‐American girls over a 2‐year period of intervention. Research Methods and Procedures: Fifty‐seven overweight (mean BMI percentile, 98.3) African‐American girls (mean age, 13.2 years) were randomly assigned to an interactive behavioral internet program or an internet health education program, the control condition. Overweight parents were also participants in the study. Forty adolescent‐parent dyads (70%) completed the 2‐year trial. Outcome data including BMI, body weight, body composition, and weight loss behaviors were collected at baseline and at 6‐month intervals. A computer server tracked use of the web sites. Results: An intention‐to‐treat statistical approach was used, with the last observation carried forward. In comparison with the control condition, adolescents in the behavioral program lost more mean body fat (BF) (?1.12 ± 0.47% vs. 0.43 ± 0.47% BF, p < 0.05), and parents in the behavioral program lost significantly more mean body weight (?2.43 ± 0.66 vs. ?0.35 ± 0.64 kg, p < 0.05) during the first 6 months. This weight loss was regained over the next 18 months. After 2 years, differences in fat for adolescents (?0.08 ± 0.71% vs. 0.84 ± 0.72% BF) and weight for parents (?1.1 ± 0.91 vs. ?0.60 ± 0.89 kg) did not differ between the behavioral and control programs. Discussion: An internet‐based weight management program for African‐American adolescent girls and their parents resulted in weight loss during the first 6 months but did not yield long‐term loss due to reduced use of the web site over time.  相似文献   

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Objective: To determine the influence of environmental factors on resting energy expenditure (REE) and its relationship to adiposity in two populations of West African origin, Nigerians and U.S. blacks. Research Methods and Procedures: REE and body composition were measured in a cross‐sectional sample of 89 Nigerian adults (39 women and 50 men), and 181 U.S. black adults (117 women and 65 men). Both groups represent randomly selected population samples. REE was measured by indirect calorimetry after an overnight fast in both sites using the same instrument. Body composition was estimated using bioelectrical impedance analysis (BIA) in 72 Nigerians and 156 U.S. participants. Multivariate regression analysis was used to determine the significant predictors of REE. The analyses were repeated in a set of 17 Nigerians and 28 U.S. blacks in whom body composition was measured using deuterium dilution. Results: U.S. black adults were significantly heavier and had both more fat‐free mass (FFM) and body fat than Nigerians. FFM was the only significant determinant of REE in both population groups, whether body composition was measured using BIA or deuterium dilution. The relationship between REE and body composition did not differ by site. There was no relationship between REE and adiposity. Discussion: Differences in current environmental settings did not impact REE. The differences observed in mean levels of body fat between Nigerians and U.S. blacks were not the result of differences in REE adjusted for body composition.  相似文献   

7.
Objective: Recent literature has documented the psychosocial consequences of pediatric obesity, including poor health‐related quality of life (HRQOL). The present study examines HRQOL and its association with depressive symptoms and perceived social support in African‐American and white youth pursuing weight management treatment. Research Methods and Procedures: Study participants were 166 obese youth (mean = 12.7 years, 70% females, 57% African American, mean BMI = 37.0) referred to a pediatric weight management program. Parents of participants completed a demographics form and the parent‐proxy Pediatric Quality of Life Inventory (PedsQL). Youth completed the Children's Depression Inventory, PedsQL, and Perceived Social Support Scale for Children. Results: HRQOL scores were quite impaired relative to published norms on healthy youth (p < 0.001). Approximately 11% of the sample met criteria for clinically significant depressive symptoms. Simultaneous regression analyses revealed that depressive symptoms, perceived social support from classmates, degree of overweight, and socioeconomic status seem to be strong predictors of HRQOL. Discussion: Obesity has a clear impact on HRQOL regardless of respondent (e.g., parent, youth) or racial group. It is likely that assessing and treating depressive symptoms and fostering social support in the context of pediatric intervention have implications for both improved HRQOL and weight management outcomes.  相似文献   

8.
In order to determine the active ingredients in root extracts of Panax quinquefolius (American ginseng), a gradient HPLC method involving UV photodiode array detection was applied to separate and quantify simultaneously the ginsenosides Rb1, Rb2, Rc, Rd, Re, Rf and Rg1. All ginseng saponins were baseline-resolved under the selected conditions, and the detection limits were 1.0 microg/mL or less. The method has been applied to analyse ginsenosides extracted from American ginseng cultivated in both Wisconsin and Illinois. Ginsenosides Re and Rb1 were the two main ginseng saponins in the root. The amounts of Re in 5- and 7-year Illinois-cultivated samples were greater than those found in ginseng cultivated for 3 or 4 years in Wisconsin, whereas the levels of Rb1 were greater in the younger Wisconsin samples.  相似文献   

9.
Objective: To assess the process variables involved in a weight loss program for African‐American adolescent girls. Several process variables have been identified as affecting success in in vivo weight loss programs for adults and children, including program adherence, self‐efficacy, and social support. The current study sought to broaden the understanding of these process variables as they pertain to an intervention program that is presented using the Internet. It was hypothesized that variables such as program adherence, dietary self‐efficacy, psychological factors, and family environment factors would mediate the effect of the experimental condition on weight loss. Research Methods and Procedures: Participants were 57 adolescent African‐American girls who joined the program with one obese parent; family pairs were randomized to either a behavioral or control condition in an Internet‐based weight loss program. Outcome data (weight loss) are reported for the first 6 months of the intervention. Results: Results partially supported the hypotheses. For weight loss among adolescents, parent variables pertaining to life and family satisfaction were the strongest mediating variables. For parental weight loss, changes in dietary practices over the course of 6 months were the strongest mediators. Discussion: The identification of factors that enhance or impede weight loss for adolescents is an important step in improving weight loss programs for this group. The current findings suggest that family/parental variables exert a strong influence on weight loss efforts for adolescents and should be considered in developing future programs.  相似文献   

10.
ABSTRACT The value of egg coloration as crypsis, once accepted as a general principle, has recently been questioned because most experiments have failed to show that egg coloration deters predation. The nest‐crypsis hypothesis postulates that, among species that build conspicuous nests, selection for egg crypsis is relaxed or absent because visually searching predators detect nests prior to eggs. I tested the nest‐crypsis hypothesis using the large, relatively conspicuous nests of American Robins (Turdus migratorius), and eggs that differed markedly in color that were collected from the nests of Red‐winged Blackbirds (Agelaius phoeniceus), Brewer's Blackbirds (Euphagus cyanocephalus), and Yellow‐headed Blackbirds (Xanthocephalus xanthocephalus). Each nest (N= 22) received a clutch of each species during three sequential predation trials that were 16 d in duration. The order of clutch presentation was randomized for each nest. Survival trends for Brewer's and Yellow‐headed Blackbirds were similar, and higher than those for clutches of Red‐winged Blackbirds. By the end of trials, overall survival of the three clutch types was roughly equivalent. However, clutches of Red‐winged Blackbird eggs, the most conspicuous egg type to the human eye, were discovered sooner by predators. Because the experimental design controlled for effects of nest crypsis, nest location, and nest size, this difference in egg survival can be attributed to differences in egg pigmentation. Thus, my results support a role for egg coloration as camouflage in conspicuous nests.  相似文献   

11.
Objective : To examine, with the use of national guidelines, coronary heart disease (CHD) risk with increasing BMI for primary prevention in urban African‐American women. Research Methods and Procedures : Participants were recruited for CHD risk factor screening from 20 churches as part of a larger study of nutrition and fitness (Project Joy). All participants had a demographic, smoking and medical history assessment, and the following measurements were taken: weight, height, waist circumference, blood pressure, lipid levels, and glucose. Three methods of defining risk, the Framingham Point Scoring System, a count of risk factors, and the presence of the multiple metabolic syndrome, based on the National Cholesterol Education Program Adult Treatment Panel III Report and BMI classes established by the Clinical Guidelines, were used. Results : A total of 396 women were eligible. Participants were 40 to 80 years of age and had marked excess prevalence of overweight and obesity (84%); 55% were obese. There was a linear increase in risk factors as BMI increased. Lipids did not differ significantly among BMI classifications. Seventeen percent of women had multiple metabolic syndrome. Eight percent and 16% of women in the normal and overweight BMI classes, respectively, had two or more modifiable risk factors. There was no difference in number of modifiable risk factors among the obese classes. The Framingham Point Scoring System assigned a <10% risk of a hard CHD event in 10 years to 97% of the women. Discussion : National risk assessment guidelines for primary prevention of CHD may not be adequate for overweight and obese urban African‐American women and require further study.  相似文献   

12.
Escallonia (Escalloniaceae) is a New World genus of c. 39 species distributed mainly in the South American highlands. Plastid DNA sequence data from the intergenic spacers trnS‐trnG and 3′ trnV‐ndhC and the ndhF gene for 32 species were used to examine the relationships among species and related genera and to analyse the relationship between phylogeny and the geographical distribution of the species. Maximum parsimony and Bayesian inference were employed to analyse the data. The sister relationship of Escallonia to Forgesia and Valdivia was corroborated. We recovered five strongly supported clades that are geographically structured, suggesting that the evolutionary history of the genus may be linked to historical processes, including the uplift of mountainous systems in South America. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 173 , 442–451.  相似文献   

13.
The present report records and describes sexual dimorphism of the talus and calcaneus in American Blacks and Whites from the Terry Collection housed in the Smithsonian Institution, Washington, D.C. The greater amount of sexual dimorphism was observed in the talus, where 81 percent of the study sample could be accurately sexed. Four discriminant functions based on measurements from the talus and/or the calcaneus allowed sexing 79 to 89% of the study sample accurately. The techniques developed were then applied to two North American Indian samples, and sex of the individuals in these samples was assessed with the same degree of accuracy.  相似文献   

14.
The origins of evolutionary radiations are often traced to the colonization of novel adaptive zones, including unoccupied habitats or unutilized resources. For herbivorous insects, the predominant mechanism of diversification is typically assumed to be a shift onto a novel lineage of host plants. However, other drivers of diversification are important in shaping evolutionary history, especially for groups residing in regions with complex geological histories. We evaluated the contributions of shifts in host plant clade, bioregion, and elevation to diversification in Eois (Lepidoptera: Geometridae), a hyper‐diverse genus of moths found throughout the Neotropics. Relationships among 107 taxa were reconstructed using one mitochondrial and two nuclear genes. In addition, we used a genotyping‐by‐sequencing approach to generate 4641 SNPs for 137 taxa. Both datasets yielded similar phylogenetic histories, with relationships structured by host plant clade, bioregion, and elevation. While diversification of basal lineages often coincided with host clade shifts, more recent speciation events were more typically associated with shifts across bioregions or elevational gradients. Overall, patterns of diversification in Eois are consistent with the perspective that shifts across multiple adaptive zones synergistically drive diversification in hyper‐diverse lineages.  相似文献   

15.
Some of the first applications of transgenic trees in North America may be for the conservation or restoration of threatened forest trees that have been devastated by fungal pathogens or insect pests. In some cases, where resistance has yet to be found in the natural population of a tree species, incorporating genes from other organisms may offer the only hope for restoration. In others, transgenics may play a role as part of an integrated approach, along with conventional breeding or biocontrol agents. American chestnut (Castanea dentata) was wiped out as a canopy species by a fungal disease accidentally introduced into the United States around 1900. Similarly, American elm (Ulmus americana) virtually disappeared as a favored street tree from Northeastern U.S. cities after the introduction of the Dutch elm disease fungus in the 1940s. In both cases, progress has been made toward restoration via conventional techniques such as selection and propagation of tolerant cultivars (American elm) or breeding with a related resistant species (American chestnut). Recently, progress has also been made with development of systems for engineering antifungal candidate genes into these “heritage trees.” An Agrobacterium-leaf disk system has been used to produce transgenic American elm trees engineered with an antimicrobial peptide gene that may enhance resistance to Dutch elm disease. Two gene transfer systems have been developed for American chestnut using Agrobacterium-mediated transformation of embryogenic cultures, setting the stage for the first tests of potential antifungal genes for their ability to confer resistance to the chestnut blight fungus. Despite the promise of transgenic approaches for restoration of these heritage trees, a number of technical, environmental, economic, and ethical questions remain to be addressed before such trees can be deployed, and the debate around these questions may be quite different from that associated with transgenic trees developed for other purposes.  相似文献   

16.
The mitochondrial DNA of modern Native Americans has been shown to fall into one of at least five haplogroups (A, B, C, D, or X) whose frequencies differ among tribal groups. The frequencies of these five haplogroups in a collection of ancient individuals from Western Nevada dating to between approximately 350-9,200 years BP were determined. These data were used to test the hypothesis, supported by archaeological and linguistic data, that the current inhabitants of the Great Basin, the Numic speakers, are recent immigrants into the area who replaced the previous non-Numic inhabitants. The frequency distributions of haplogroups in the ancient and modern Native Americans differed significantly, suggesting that there is a genetic discontinuity between the ancient inhabitants and the modern Numic speakers, providing further support for the Recent Numic Expansion hypothesis. The distribution of mitochondrial haplogroups of the ancient inhabitants of the Great Basin is most similar to those of some of the modern Native American inhabitants of California.  相似文献   

17.
After a general discussion of some of the limitations and assumptions inherent in paleodemographic studies, a method for the estimation of average life expectancy when only deaths by age are known is described and applied to the remains from Point of Pines, a prehistoric Western Pueblo population from the American Southwest. It was found that the method was not applicable to these data in its entirety, since there were considerable differences in mortality shapes between this prehistoric group and those summarized in the U. N. Model Life Tables. It is suggested that a range of average life expectancy can be calculated when the intrinsic rates of natural increase vary, and these are given for the Point of Pines data.  相似文献   

18.
The name “Wampanoag” means “Eastern People” or “People of the First Light” in the local dialect of the Algonquian language. Once extensively populating the coastal lands and neighboring islands of the eastern United States, the Wampanoag people now consist of two federally recognized tribes, the Aquinnah and Mashpee, the state‐recognized Seaconke Wampanoag tribe, and a number of bands and clans in present‐day southern Massachusetts. Because of repeated epidemics and conflicts with English colonists, including King Philip's War of 1675–76, and subsequent colonial laws forbidding tribal identification, the Wampanoag population was largely decimated, decreasing in size from as many as 12,000 individuals in the 16th century to less than 400, as recorded in 1677. To investigate the influence of the historical past on its biological ancestry and native cultural identity, we analyzed genetic variation in the Seaconke Wampanoag tribe. Our results indicate that the majority of their mtDNA haplotypes belongs to West Eurasian and African lineages, thus reflecting the extent of their contacts and interactions with people of European and African descent. On the paternal side, Y‐chromosome analysis identified a range of Native American, West Eurasian, and African haplogroups in the population, and also surprisingly revealed the presence of a paternal lineage that appears at its highest frequencies in New Guinea and Melanesia. Comparison of the genetic data with genealogical and historical information allows us to reconstruct the tribal history of the Seaconke Wampanoag back to at least the early 18th century. Am J Phys Anthropol 142:579–589, 2010. © 2010 Wiley‐Liss, Inc.  相似文献   

19.
Objective: To assess role of BMI, gender, and acculturation on maternal and children's perception of body size, body ideal, and attractiveness. Research Methods and Procedures: Eighty mothers and their 6‐ to‐ 12‐year‐old children (41 boys, 39 girls) participated. Maternal and children's perceptions of body size (actual and ideal) and attractiveness were assessed through a pictorial instrument. Mother and child height and weight, demographic, and acculturation characteristics were also assessed. Results: Seventy‐nine percent of the mothers were overweight, and 32% of the boys and 34% of the girls were overweight or at‐risk for overweight. BMI influenced the children's selection of perceived ideal size. Overweight or at‐risk for overweight children were more likely to select thinner figures as the ideal size than non‐overweight children. Gender and acculturation differences concerning children's perceptions of body size and attractiveness were also found. Girls perceived the obese figure as being less attractive than did the boys. More acculturated children were likely to select thinner figures as more attractive than their less acculturated counterparts. Maternal acculturation was associated positively with the girls’ choice of thinner figures as an ideal body size, but not with the boys. Mothers viewed their daughters’ actual body size and BMI as ideal, although 34% of the girls were at‐risk for overweight. Mothers perceived average body size figures as more attractive for their sons. Discussion: Findings from this study provide empirical data about the role of BMI, gender, acculturation, and familial influences on children's perceptions of actual and ideal body sizes and attractiveness.  相似文献   

20.
The South American hystricognath rodents are one of the most diverse mammalian clades considering their occupied habitats, locomotor modes and body sizes. This might have been partly evolved by diversification of their masticatory apparatus' structure and its ecological commitment, for example, chisel‐tooth digging. In this phylogeny‐based comparative study, we test the relationship between ecological behavior and mechanical features of their incisors and molariforms. In 33 species of nine families of caviomorph rodents, we analyze incisor attributes related to structural stress resistance and molar features related with grinding capacity, for example, second moment of inertia and enamel index (EI) (enamel band length/occlusal surface area), respectively. Most of these variables scaled isometrically to body mass, with a strong phylogenetic effect. A principal component analysis discrimination on the EI clustered the species according to their geographic distribution. We presume that selective pressures in Andean–Patagonian regions, on particular feeding habits and chisel‐tooth digging behaviors, have modeled the morphological characteristics of the teeth. Subterranean/burrower ctenomyids, coruros, and plains viscachas showed the highest bending/torsion strength and anchorage values for incisors; a simplified enamel pattern in molariforms would be associated with a better grinding of the more abrasive vegetation present in more open and drier biomes. J. Morphol. 2012. © 2012 Wiley Periodicals, Inc.  相似文献   

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