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1.
Interethnic marriage represents a major trend in the demographic history of American Indians. While the majority of these unions involved Indian women and Caucasian men, a sizeable number occurred between Indians and African Americans. The children of these bicultural marriages were “mixed bloods” who in turn typically married non-Indians or other mixed bloods. Using data from the 1910 Census on American Indians in the United States and Alaska, this article explores why American Indians with African ancestry enjoyed high fertility. Differential rates of fertility among American Indians in the past were due to a number of underlying genetic, cultural, and environmental factors. By identifying these factors, the paradox of why Indian women with African heritage did so well in terms of fertility largely disappears. African admixture, however, greatly complicates Indian social identity.  相似文献   

2.
Although human musical performances represent one of the most valuable achievements of mankind, the best musicians perform imperfectly. Musical rhythms are not entirely accurate and thus inevitably deviate from the ideal beat pattern. Nevertheless, computer generated perfect beat patterns are frequently devalued by listeners due to a perceived lack of human touch. Professional audio editing software therefore offers a humanizing feature which artificially generates rhythmic fluctuations. However, the built-in humanizing units are essentially random number generators producing only simple uncorrelated fluctuations. Here, for the first time, we establish long-range fluctuations as an inevitable natural companion of both simple and complex human rhythmic performances. Moreover, we demonstrate that listeners strongly prefer long-range correlated fluctuations in musical rhythms. Thus, the favorable fluctuation type for humanizing interbeat intervals coincides with the one generically inherent in human musical performances.  相似文献   

3.
The American Indian and Alaskan Native population has grown rapidly since 1950 because of changes in the racial classification of persons with mixed Indian and non‐Indian descent. These changes have challenged once common expectations that the Indian population was likely to shrink over time through assimilation. However, in regions of the United States where the recent growth of the Indian population has been particularly sharp most married Indians are married to non‐Indians. Fertility rates of women who are part of intermarried couples are lower than fertility rates for Indian women in racially endogamous marriages. The majority of the children of intermarried Indians in high intermarriage regions are labelled with the race of the non‐Indian parent. Intermarriage is likely to substantially reduce the long‐run impact of changes in identification on the future growth of the Indian population. At the same time, in a few states the American Indian population remains ethnically homogenous and shows no signs of imminent amalgamation into the general American population.  相似文献   

4.
《Plains anthropologist》2013,58(100):119-128
Abstract

In the late 1800s, boarding schools sponsored by the United States government were created for the education and socialization of American Indian youth. These institutions gradually and purposefully pursued a policy of total assimilation of American Indians into the mainstream of society. The boarding schools failed in their ultimate goal to assimilate Indians. Surprisingly, however, they did attain limited acceptance among many Oklahoma Indians. The segregationist policies of the boarding schools are interpreted as having inadvertently perpetuated the formation of an Indian identity. Frequent visiting by family, segregation of Indian from non-Indian students, and symbolic association of the boarding schools with federal government obligations are identified as factors which contributed to the maintenance of this identity.  相似文献   

5.
Social scientists have utilized daily time use studies as one method of understanding everyday lives. The bulk of this research, usually quantitative, identifies broad racial, ethnic and gender differences. Yet, certain groups and questions are typically excluded in daily time use research. One such group is American Indians. To address this lacuna, we look at the deeply discussed view that American Indians are closer to nature than other US ethnic groups. We use a nationally representative sample of individual daily time use (American Time Use Survey; n?=?136,960) to look at leisure time outdoors. Our results show that American Indians report greater time spent outdoors but that this is only statistically significant for those who identify as exclusively American Indian (not for American Indians that are multi- and bi-racial). This study confirms previous qualitative research that suggests American Indians have a distinct relationship with nature.  相似文献   

6.
We report for the first time that the endogenous, pseudo‐steady‐state, specific intracellular levels of the hydroxyl radical (si‐OH) oscillate in an ultradian fashion (model system: the microalga, Chlorella vulgaris), and also characterize the various rhythm parameters. The ultradian rhythm in the endogenous levels of the si‐OH occurred with an approximately 6 h period in the daily cycle of light and darkness. Further, we expected that the rhythm reset to a shorter period could rapidly switch the cellular redox states that could favor lipid accumulation. We reset the endogenous rhythm through entrainment with UVA radiation, and generated two new ultradian rhythms with periods of approximately 2.97 h and 3.8 h in the light phase and dark phase, respectively. The reset increased the window of maximum lipid accumulation from 6 h to 12 h concomitant with the onset of the ultradian rhythms. Further, the saturated fatty acid content increased approximately to 80% of total lipid content, corresponding to the peak maxima of the hydroxyl radical levels in the reset rhythm. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:673–680, 2014  相似文献   

7.
Stewart ('62) and Walensky ('65) indicated that while the metrical expression of anterior femoral curvature alone will not always differentiate between Whites, American Negroes, and North American Indians, it was very useful as a racial criterion in combination with observed traits such as torsion, pilastry, and cross-sectional shape. Seven additional North American Indian groups reported here, representing both pre-Columbian and post-contact times, upheld the observation that anterior femoral curvature is a useful feature of racial assessment for Negroes, Whites and North American Indians. However, two South American groups studied (Ecuador and Peru) were only slightly more curved than American Negroes, and were less curved than Whites and North American Indians. The metrical expression of anterior femoral curvature therefore is not a useful feature of racial assessment for separating these two South American Indian groups from Whites and American Negroes. Femora of American Negro and White individuals with low ponderal indices were found to be less bowed than the norms for their race; individuals with high ponderal indices were more bowed than the norm for their race. The assumed genetic basis for expression of anterior femoral curvature suggested by Stewart ('62) and Walensky ('65) seems to be a feature of human plastic response to body weight rather than to temporal, clinal, postural or equestrian influences.  相似文献   

8.
Among the Jivaro Indians of Eastern Ecuador, very low non-taster frequencies were found, a situation in accord with most of the other, through few sets of P. T. C. data available for South American Indians. The Jivaro have maximal frequencies (1.000) of the alleles I° and D, typical of most South American Indian groups. The colour blindness frequency of males (7.1%) is seemingly higher than North American Indian figures and is similar to European frequencies. Jivaro dermatoglyphic data are in broad general agreement with data available for Amerindian groups generally, and for many Asian mongoloids, with high pattern intensity indices for males and females, mainly the result of a very high whorl incidence. The digital distribution of the pattern types for the greater part accords with the generalisations of Cummins and Midlo ('61). There are marked sex differences in the data, females having a lower mean pattern intensity index, a higher value for Dankmeijer's Index and a lower value for Furuhata's Index. Unfortunately there are few other sets of South American Indian data available for comparative purposes.  相似文献   

9.
Three-rooted mandibular first molars (3RM1) are characteristic of Asian and Asian-derived populations, particularly Aleuts (whose 3RM1 frequency is the highest in the world) and Eskimos. Similarities in the frequency of these teeth between American Indians and contemporary peoples of southeastern Asia indicate a closer relation between these groups than between American Indians and Aleut-Eskimos. Three-rooted mandibular first molar frequency does not differ significantly in males and females except in Aleut-Eskimos. Bilateral asymmetry of 3RM1 is relatively frequent in both sexes and all groups. All American Indian groups examined have a low frequency of 3RM1 pointing to a single Asian origin, except Athabaskan-speaking Arizona Navajos, whose 3RM1 frequency approaches that of Aleut-Eskimos. There is no evidence at present of any significant local microevolution of 3RM1 in two testable prehistoric American Indian groups, although genetic drift had possibly occurred in a few series of 3RM1-deficient southwestern U. S. prehistoric Western Pueblo Indians. No adaptive value can be found for 3RM1 in Indians. In prehistoric western U. S. Indians geographic frequency variation is only slightly greater than the very slight (and non-significant) testable temporal variation. Three migrations from Asia seem best to explain New World 3RM1 frequency variation.  相似文献   

10.
The frog, with two distinct ventilatory acts, provides a useful model to investigate the prospective interaction of two oscillators in generating the respiratory rhythm. Building on evidence supporting the existence of separate oscillators generating buccal and lung ventilation, we have attempted to uncouple the two rhythms in the isolated brain stem preparation. Opioid preferentially inhibits the lung rhythm, suggesting an uncoupling of the lung from the buccal oscillator. Reduction of the superfusate chloride concentration alters both the buccal and the lung rhythms. Joint application of opioid and reduced-chloride superfusate leads to an increase in the variability of the buccal burst-to-lung burst intervals. This increase in variability suggests that chloride-mediated mechanisms are involved in coupling the buccal oscillator to the lung oscillator. Given the results from these interventions, we propose a simple schematic model of the frog respiratory rhythm generator, outlining the coupling of the lung and buccal oscillators.  相似文献   

11.
实验报道了心肌细胞团自发性同步化搏动的一类新节律——整数倍节律。这种稳定的节律模式由两种相关的搏动形式的随机交替出现形成,这两种搏动形式中任何一种的出现间期具有整数倍特征。在静息状态和周期1搏动间的随机交替形成0-1整数倍节律,在周期1搏动和周期2搏动之间的随机交替形成l-2整数倍节律。0-1整数倍是居于静息状态和周期1节律之间的节律模式,1-2整数倍是居于周期1节律和周期2节律之间的节律模式,实验所见的节律转迁过程清楚地展示了静息状态、0-1整数倍节律、周期1节律、1-2整数倍节律、周期2节律等顺序地构成的一种“节律谱系”。“节律谱系”的观念可以为认识正常和异常心律的关系和其间的转迁机制提供深刻的理论启示。  相似文献   

12.
ABSTRACT

Is the #NoDAPL mobilization, which was historically unusual as a national scale grassroots campaign featuring American Indians grassroots activists and tribal governments in coalition with others, an indicator of future similar efforts? Or, will the Standing Rock resistance be a relative aberration, based on a unique set of circumstances? To explore these questions, I draw upon theory and historical scholarship about American settler colonialism; cross-group collaborations and social movement coalitions; and American Indian movements. A variety of within-group, intergroup and larger structural factors pose significant obstacles to American Indian participation in grassroots social movement coalitions. However, striking threats, the existence of social ties between American Indian movements and environmental movements, and overlap between ideologies and frames generated by each movement were sufficient to generate robust coalitional mobilization.  相似文献   

13.
A K Ho  C L Chik  G M Brown 《Life sciences》1985,37(17):1619-1626
Both the environmental light-dark cycle and scheduled feeding can act as entrainers of biological rhythms. The present study investigated the relative potency of these two environmental cues in entraining the rhythms of circulating tryptophan (TRP), serotonin (5HT) and N-acetylserotonin (NAS). Four groups of rats were subjected for one month to an identical light-dark cycle of 14 h light and 10 h dark with food availability restricted to the 3 h period beginning 2 h after onset of light or onset of darkness. Two groups of animals were food deprived on the day of experiment. The 24 h rhythms of serum TRP, 5HT and NAS were determined. Serum TRP showed a sharp increase after food presentation and declined gradually to a trough just before feeding. Withholding food on the day of experiment abolished this increase. The trough of serum 5HT occurred just before feeding, increased gradually after feeding and peaked 10-13 h afterwards. Serum NAS levels, however, demonstrated an anticipatory rise before feeding, which peaked during feeding and declined to a trough 8 h afterwards. Unlike TRP, withholding food had no effect on either the 5HT or the NAS rhythm. These results indicated that feeding schedule was the common and stronger entrainer for the rhythms of serum TRP, 5HT and NAS. However, each indole had a different rhythm pattern in relation to the feeding schedule which could not be explained by a simple precursor-product relationship.  相似文献   

14.
Abstract

The count of American Indians in the 1980 census was over 70 per cent larger than the 1970 census count. An assessment of the demographic basis for this change shows that the cohorts from ages 10 to 74 in 1980 increased by substantial amounts, reaching 35 per cent for many ages. Increases of this nature in the absence of immigration are demographically impossible—an indication that the changes in response patterns identified by Passel (1976) between the 1970 and 1960 censuses persisted in 1980, possibly at even greater levels.

In addition to presenting demographic analyses of the American Indian data at the national level, this paper includes an analysis of geographic variation of implied birth, death, and migration rates at the state level. States which historically have had large American Indian populations in general had high birth and death rates with reasonable migration rates. Many other states, however, had anomalously low birth and death rates with extraordinarily high implied migration rates. This pattern suggests that the changes in response may have occurred primarily in the latter areas.

Several other anomalies in the American Indian data are reported here. The sample figure for American Indians from the 1980 census exceeds the complete count by more than 8 per cent at the national level. Increases occurred in most states, but the amount of increase varied substantially. Also, the increases tend to occur outside American Indian areas (reservations, tribal trust lands, etc.). Such differences are, for the most part, outside of expected sample variability. Furthermore, differences in the number of persons reporting American Indian race and American Indian ancestry were substantial. Some of the causes of these differences are investigated here. The paper concludes with an overall assessment of the quality and utility of these census data for various types of analysis.  相似文献   

15.
Abstract

This article describes, in quite general terms, the current condition of the Indians of Oklahoma, with particular attention given the Cherokee. The author views the system of allotments in severalty and the policies of the Bureau of Indian Affairs as principal factors underlying the increased rate of assimilation of the Oklahoma tribes. She deals briefly with the Native American Church, and cites this as evidence of a reaction to assimilation on the part of the Indians.  相似文献   

16.
Circadian Stomatal Rhythms in Epidermal Peels from Vicia faba   总被引:6,自引:4,他引:2       下载免费PDF全文
Circadian rhythms in stomatal aperture and in stomatal conductance have been observed previously. Here we investigate circadian rhythms in apertures that persist in functionally isolated guard cells in epidermal peels of Vicia faba, and we compare these rhythms with rhythms in stomatal conductance in attached leaves. Functionally isolated guard cells kept in constant light display a rhythmic change in aperture superimposed on a continuous opening trend. The rhythm free-runs with a period of about 22 hours and is temperature compensated between 20 and 30°C. Functionally isolated guard cell pairs are therefore capable of sustaining a true circadian rhythm without interaction with mesophyll cells. Stomatal conductance in whole leaves displays a more robust rhythm, also temperature-compensated, and with a period similar to that observed for the rhythm in stomatal aperture in epidermal peels. When analyzed individually, some stomata in epidermal peels showed a robust rhythm for several days while others showed little rhythmicity or damped out rapidly. Rhythmic periods may vary between individual stomata, and this may lead to desynchronization within the population.  相似文献   

17.
Indigenous Indian groups comprise approximately 20% of Ecuador's population, the third largest percentage in all of Central or South America, yet immunogenetic data on these groups are lacking in the literature. In the course of population migration studies, sera collected from 65 Ecuadorians living in the northern province of Esmeraldas were typed for six GM and two KM markers. The study population consisted of 47 Cayapa Indians and 18 blacks of African origin, descendants of slaves imported into the area during the seventeenth century. The Cayapa demonstrated three GM phenotypes, two of which are common to other South American Indian tribes. The frequency of KM1 positive Cayapa Indians (63%) is similar to other South American Indian tribes, but is significantly greater than the Huaorani of eastern Ecuador (2%), the only other Ecuadorian Indian group for whom limited immunoglobulin allotype data are available ( 2=35.8, P<0.0001).  相似文献   

18.

Background

Genotype imputation is commonly used in genetic association studies to test untyped variants using information on linkage disequilibrium (LD) with typed markers. Imputing genotypes requires a suitable reference population in which the LD pattern is known, most often one selected from HapMap. However, some populations, such as American Indians, are not represented in HapMap. In the present study, we assessed accuracy of imputation using HapMap reference populations in a genome-wide association study in Pima Indians.

Results

Data from six randomly selected chromosomes were used. Genotypes in the study population were masked (either 1% or 20% of SNPs available for a given chromosome). The masked genotypes were then imputed using the software Markov Chain Haplotyping Algorithm. Using four HapMap reference populations, average genotype error rates ranged from 7.86% for Mexican Americans to 22.30% for Yoruba. In contrast, use of the original Pima Indian data as a reference resulted in an average error rate of 1.73%.

Conclusions

Our results suggest that the use of HapMap reference populations results in substantial inaccuracy in the imputation of genotypes in American Indians. A possible solution would be to densely genotype or sequence a reference American Indian population.  相似文献   

19.
Abstract

Mortality rates by age and sex of American Indians living in reservation and non‐reservation counties were compared for 1970 and 1978. An apparent overcount in the 1980 census enumeration of American Indians curtails rigorous comparisons, but broad differences can be delineated. The main improvement in American Indian mortality during the decade was in age group 0–4. In 1970, non‐reservation death rates were not different from reservation rates. By the end of the decade, non‐reservation death rates had diverged downward from reservation deaths. An analysis of 1978 death rates by poverty status showed that non‐reservation death rates are sensitive to county poverty level, whereas reservation death rates are not.  相似文献   

20.
Formation of trace rhythm recruitment (an analogue of conditioned time reflex) was studies in CA3 hippocampal neurons of alert young (less than one year), old (54-65 months), and very old rabbits after a prolonged (10-20 min) electro-cutaneous stimulation of a forelimb with the frequency of 0.5-1 Hz. Comparative analysis of neuronal spike activity in young and old rabbits showed that in the late ontogeny the number of spontaneously active neurons was significantly decreased, the proportion of slowly firing neurons increased, the interspike intervals and intervals between spike groups became longer, the number of spikes in a group reduced. The ability of hippocampal neurons to acquire and reproduce the rhythm of the previous stimulation declined with age. No appropriate rhythms were found in neurons of very old animals. A nonspecific increase in neuronal baseline activity was observed in old rabbits after the stimulation. Deterioration of morphological structures of hippocampal neurons and glial cells may explain the impairment of mnestic processes in late ontogeny.  相似文献   

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