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I analyzed the finger prints of 59 male and 48 female unrelated Bengalis in a rehabilitation camp of Dacca, Bangladesh. The most common pattern type in the Bengalis was the ulnar loop (53%), then whorls (40%); arches (5%) and radial loops (2%) were the least common. Radial loops occurred most frequently on the index fingers. I have shown the arch/whorl, whorl/loop, and pattern intensity indices, and I have presented ridge counts by individual digits and by total digital ridge count. Digital dermatoglyphics in the male Bangladeshis were similar to previous findings in male Brahmins of Bengal. However, there were more whorls and arches, fewer loops, and a higher mean total digital ridge count in the female Bangladeshis than in female Brahmins.  相似文献   

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Recent evidence suggests that reaching movements are more accurate when end point contact occurs, suggesting that fingertip contact contributes to a final estimation of arm position. In the present study we tested two hypotheses: 1). that fingertip contact influences illusions of arm movement produced by muscle vibration and 2). that this influence depends on the a priori context of the stability of the contact surface. Subjects sat with their elbows on a table and eyes closed. They demonstrated the perceived orientation of the left (cue) arm by mirroring the location with the right (report) arm. We manipulated deep proprioceptive cues by vibrating the left biceps brachia, causing illusions of elbow extension, and tested whether these illusions were altered when the fingertip remained in contact with a stable external surface. The context at this point represents a prior assumption that the external contact surface is stable. Midway through the experiment, the context was changed by challenging the prior assumption that the contact surface was stable by demonstrating that it could move. Unbeknownst to the subject, the external contact surface remained stable during data collection throughout the experiment. As expected, without tactile cues, biceps vibration caused illusory elbow extension. Conditions with fingertip contact and biceps vibration in the stable context demonstrated that contact largely eliminated the overestimation of cue arm elbow angle. However, in the context of a possibly unstable (movable) contact surface, the reports of elbow extension returned. Thus a priori notions about the stability context of an external contact surface influence how this tactile cue is integrated with proprioceptive sensory modalities to generate an estimate of arm location in space. These findings support the notion that tactile cues are used to calibrate proprioception against external spatial frameworks.  相似文献   

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昆虫的母代效应   总被引:1,自引:0,他引:1  
母代效应,由于其特殊的作用方式,引起了许多进化生态学家的极大兴趣。近年来,随着研究的不断深入,特别是数量遗传学的引入,使该领域的研究取得了令人瞩目的成绩。该文就这几十年来对母代效应研究进行综述,论述昆虫生活史中的母代效应及其适应意义,阐明以下几个问题:(1)母代效应影响昆虫哪些特征;(2)环境因素对母代效应的影响;(3)母代对环境刺激的敏感期;(4)子代受母代效应调控的敏感期;(5)母代效应调控子代生长发育的生化机制;(6)种群内和种群间母代效应的基因差异。  相似文献   

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To look for a persistent maternal effect of CL(P) and CP, 8,000 pedigrees were screened for half sibships, and data were pooled from 16 investigators. After excluding known genetic or cytogenetic diagnoses from the probands with facial clefts, a recurrence risk of .011 was obtained for CL(P) based upon 342 maternal half sibs. This was nearly identical to the risk of .014 based upon 210 paternal half sibs. CP proband frequencies of .004 for maternal half sibs and .009 for the paternal counterparts were also found. The lack of significant maternal effects in this data supports previously reported data from twin studies and from interracial crosses from Hawaii. The lack of maternal effect in human CL(P) and CP is in contrast to genetic data on clefting in mice.  相似文献   

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The febrile response to administration of endotoxin has been reported to be suppressed in both pregnant animals at term and in their newborn. In a previous study we found that newborn rabbits under appropriate conditions to develop a febrile reaction to injected endotoxin. In this investigation we sought to discover whether pregnant rabbits at term had a febrile response to endotoxin, and if so, its effect on thermoregulation in their newborn. Endotoxin (E. Coli LPS) was injected into 19 pregnant rabbits at term. Six delivered spontaneously within an hour. At one hour, 13 were given oxytocin, and a further 8 delivered within five minutes. The colonic temperature (Tc) of the mothers before endotoxin administration and at delivery, and of their young, was measured. The results were compared with those of 10 pregnant rabbits not given endotoxin, and their young. Within 15 min of delivery newborn rabbits from each litter were placed on a thermal gradient to assess their thermoregulatory responses. Pregnant rabbits at term developed an impressive febrile response to injected endotoxin and their young were born with high colonic temperatures. Newborn rabbits from febrile mothers selected higher thermal environments and maintained a higher colonic temperature than the newborn of non-febrile mothers. We conclude that fever is sustained in the first hours of life in the newborn of mothers injected with endotoxin. The possible mechanisms are of considerable interest. None of the pregnant rabbits died after endotoxin administration, but the stillbirth rate was 50% compared with 10% in non-febrile does.  相似文献   

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Palmar dermatoglyphic prints were taken of 261 dyslexics (173 males and 88 females) and compared against those of 707 controls (372 males and 335 females). Dyslexics of both sexes were found to exhibit greater complexity in terms of ridge count and pattern location than controls, particularly on the left hand. Specifically, both male and female dyslexics exhibited higher left a-b counts, wider atd angles on both palms, and higher frequencies of pattern in left interdigital area IV. Additionally, male dyslexics also had higher right a-b counts and greater frequency of pattern in the left hypothenar area. Dyslexics of both sexes were also found to have more distally located axial triradii, and investigation of bilateral asymmetry found dyslexics to exhibit more directional asymmetry than controls in the variable of a-b count, with the left value for both groups being greater than the right. It was concluded that the study evidenced strong support for the hypothesis that some causative factor relating to the development of dyslexia is operating during the time period in which dermatoglyphic features are formed. The relevance of these findings in terms of the Geschwind hypothesis and the possible importance of prenatal testosterone are discussed.  相似文献   

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Digital and palmar dermatoglyphics of 184 male and 224 female normal American Negroes were evaluated for digital patterns, digital ridge counts, palmar patterns, palmar main line terminations, accessory triradii and palmar creases. All subjects were seven year olds examined and found free of chronic or other genetic diseases. The results were presented for the left and right hand for the most part comparable to those of the African and other American Negro groups reported earlier. The distributions of the various dermatoglyphic features among the Negroes taken as a group were compared to those of the other racial groups and their differences were discussed.  相似文献   

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The low incidence of a tibial loop in the distal hypothenar area of the sole is suggested as a diagnostic feature for XYY patients. No other prepubertal feature is on record.  相似文献   

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Finger dermatoglyphics of the Tibetans   总被引:1,自引:0,他引:1  
Finger prints of 156 Tibetan males and 150 females have been analyzed. Whorls are more abundant in Tibetan males (60.24%) than in females (48.67%). The index of pattern intensity shows a higher value in males (15.95) than the females (14.65). The bimanual differences (both in males and females) are not statistically significant for the occurrence of pattern on the digits of the right and left hands. However, the difference between the sexes for the occurrence of patterns on the finger balls, are statistically significant. Ridge counting was done for each finger. On all fingers, Tibetan males have higher ridge-counts than females. The possible tendency for the right hands to possess higher ridge-counts cannot be demonstrated statistically. Tibetans show greater affinity with the Southern Mongoloids in the frequency distributions of pattern types on the finger balls. However, a more detailed dermatoglyphic study of all the Mongoloid populations in South East Asia, Central Asia and Far East would yield information of great value in disclosing the palmar pattern distributions among the Mongoloids.  相似文献   

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Digital and palmar dermatoglyphics were collected from 360 male and 360 female seven year old Caucasians from the greater Boston area. All participants were screened and found to be free of minor anomalies or chronic diseases. All individuals with I.Q. scores below 70 were also excluded. The results were presented in such a way as to give information on bilateral symmetry as well as overall frequencies of the various dermatoglyphic features. The results were compared with those of the corresponding sample of seven year old normal male and female Negrose of the accompanying report. A review of the distribution of the dermatoglyphic features in different Caucasian populations has also been presented and the overall dermatoglyphics of the Caucasians were discussed in reference to the distribution of the same features in the other major “racial” groups. The method of collection and selection of the subjects, described in the text, makes this set of data unique and one of the most suitable for use as controls in studying the dermatoglyphics of the individuals with diseases or congenital anomalies.  相似文献   

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Maternal and paternal effects can lead to complicated evolutionary dynamics, including evolution in the opposite direction to selection. Recent studies demonstrate that parental effects on sexually selected traits, as well as preferences for those traits, might be large. Although these findings are likely to have consequences for both the evolutionary dynamics and equilibria of sexual selection, theory is lacking. Because parents are expected to maximize their own fitness, rather than that of a specific offspring, the magnitude (and even direction) of parental effects are context dependent. By extension, this dynamic nature of parental effects might help to explain the maintenance of variation in many sexually selected traits.  相似文献   

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