首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Joint range of motion and physical capacities have been shown to change with age in both throwing athletes and non-athletes. The age of professional baseball pitchers could span from late teens to mid-40s. However, the effects of age on the pitching kinematics among professional baseball pitchers are still unknown. In this study, 67 healthy professional baseball pitchers were tested using a 3D motion analysis system. Their mean age was 23.7+/-3.3 years (range 18.8-34.4). The 12 pitchers more than one standard deviation older than the mean (i.e., older than 27.0 years) were categorized into the older group, and the 10 pitchers more than one standard deviation younger than the mean (i.e., younger than 20.4 years) were defined as the younger group. In all, 18 kinematic variables (14 position and 4 velocity) were calculated, and Student's t-tests were used to compare the variables between the two groups. Six position variables were found to be significantly different between the two groups. At the instant of lead foot contact, the older group had a shorter stride, a more closed pelvis orientation, and a more closed upper trunk orientation. The older group also produced less shoulder external rotation during the arm cocking phase, more lead knee flexion at ball release, and less forward trunk tilt at ball release. Ball velocity and body segment velocity variables showed no significant differences between the two groups. Thus, differences in specific pitching kinematic variables among professional baseball pitchers of different age groups were not associated with significant differences in ball velocities between groups. The current results suggest that both biological changes and technique adaptations occur during the career of a professional baseball pitcher.  相似文献   

2.
The effects of music with specific intensity on the latencies of the left or right hand motor responses to visual stimuli have been studied. When the latency of the initial motor response is more than 400 ms, the music accompaniment decreases the latency of the motor response of the left hand. It is supposed that the decrease in the mean latency of the left hand response in subjects who are not professional musicians is related to the activation effect of music on the right hemisphere. Music has no effect when the initial motor responses have shorter latencies.  相似文献   

3.
2,596 Aroras and 2,629 Khatris comprising six endogamous groups of the Punjabis have been studied for A1A2BO blood groups and secretion of ABO(H) group specific substances. The values of chi-square and the genetical difference (G2) among these groups do not show statistically significant differences in these groups regarding the genetical characters studied. There is a closer affinity between Beri and Bunjahi on the one hand and Uttaradhi and Dhakhandian on the other and also between Uttaradhi and Khukhran; Dhakhandian and Sareen show a great difference among themselves as well as with other groups. The comparison of ABO blood group distribution and secretor factor among the different populations of India show that the distribution is similar among the North Indians.  相似文献   

4.
Dermatoglyphic features of 52 male patients with borderline personality disorder (BPD) were compared with those of 200 male controls (control group-CG) and 195 males with schizophrenia (SCH). Quantitative analysis showed statistically significant differences between BPD-CG and between BPD-SCH, mainly regarding the palmar traits, but also the 5th, the 4th and the 1st finger of the right hand as well as the 5th and the 4th finger of the left hand between BPD and SCH patients. The canonical discriminant analysis permitted correct classification with 69.84% probability between the BPD and CG and with 76.11% probability between the BPD and the SCH group. Qualitative finger and palmar traits analysis showed differences between the BPD and SCH groups on the 3rd finger of the left hand, total frequency for all fingers and in the III interdigital space. Significant differences between the BPD and CG were found on the 3rd finger of the left hand. Our results show that the dermatoglyphic features of BPD differ from those of schizophrenia and from those of control subjects. The possible significance of these findings is discussed.  相似文献   

5.
Arthropods are common in marine, freshwater, terrestrial, and even aerial environments. The arthropod nervous systems must be adjusted to the highly diverse behaviour and requirements of the individual arthropod species. This raises the question of how the underlying patterning mechanisms have changed during arthropod evolution to produce the characteristic axonal scaffold on the one hand and allow for variations in neuronal networks on the other hand. Here we show that the overall number of the neural precursor groups/neuroblasts as well as their spatial arrangement in rows and columns is similar in all four arthropod groups indicating a common origin of this pattern. Furthermore, we demonstrate differences in the expression pattern of the columnar gene muscle segment homeobox and both differences in the expression and regulation of the neural subtype specific genes even-skipped and islet. This variation may underlie the evolutionary variations in neural identity in the individual arthropod groups. Furthermore, we discuss to what extent the stereotyped pattern of neural precursors is required for the conserved axonal scaffold and thus might have been constrained along with the underlying patterning mechanisms.  相似文献   

6.
The pottical type, palmar and plantar digital formulae, hand clasping, arm folding, handedness, leg folding and stride type have been investigated on a sample of 143 male and 160 female students of the Daur population of Molidawa Banner, Inner Mongolia. The results of this study are the following: 1. the frequency of the hyperextensive pottical type is 49.17%, the relative length of index over annularis 12.21%, right hand clasping 45.87%, right arm folding 49.50%, right handedness 94.39%, right leg folding 72.28% and right stride type 44.88%, 2. pottical type, hand clasping, handedness, leg folding and stride type do not show significant sex differences, 3. there are some relations between hand clasping and arm folding as well as between arm folding and stride type, 4. compared with other population groups, the Daur population shows a low frequency of right hand clasping, a moderate frequency of right arm folding and a low frequency of left handedness.  相似文献   

7.
The concept of non-self recognition through germ-line encoded pattern recognition receptors (PRRs) has been well-established for professional innate immune cells. However, there is growing evidence that also T cells employ PRRs and associated effector functions in response to certain non-self or damage signals. Inflammasomes constitute a special subgroup of PRRs that is hardwired to a signaling cascade that culminates in the activation of caspase-1. Active caspase-1 processes pro-inflammatory cytokines of the IL-1 family and also triggers a lytic programmed cell death pathway known as pyroptosis. An increasing body of literature suggests that inflammasomes are also functional in T cells. On the one hand, conventional inflammasome signaling cascades have been described that operate similarly to pathways characterized in innate immune cells. On the other hand, unconventional functions have been suggested, in which certain inflammasome components play a role in unrelated processes, such as cell fate decisions and functions of T helper cells. In this review, we discuss our current knowledge on inflammasome functions in T cells and the biological implications of these findings for health and disease.  相似文献   

8.
Pollinating animals and their angiosperm hosts often show strong co-adaptation in traits that increase the likelihood of a successful transfer of pollen and nutrient rewards. One such adaptation is the reported colour difference caused by unequal distribution of anthocyanidin pigments amongst plant species visited by hummingbirds and passerines. This phenomenon has been suggested to reflect possible differences in the colour vision of these pollinating birds. The presence of any such difference in colour vision would arguably affect the ecological and evolutionary interactions between flowers and their visitors, accentuating differences in floral displays and attractiveness of plants to the favoured avian pollinators. We have tested for differences in colour vision, as indicated by the amino acid present at certain key positions in the short-wavelength-sensitive type 1 (SWS1) visual pigment opsin, between the major groups of pollinating birds: the non-passerine Trochilidae (hummingbirds), the passerine Meliphagidae (honeyeaters) and Nectariniidae (sunbirds) plus five other Passerida passerine families. The results reveal gross spectral sensitivity differences between hummingbirds and honeyeaters, on the one hand, and the Passerida species, on the other.  相似文献   

9.
唐孝准  郭鹏  张丽华  汪多平 《蛇志》2021,(1):104-106
目的 探讨慕课(Massive Open Online Course,MOOC)-病例为基础(Case-Based Learning,CBL)的教学模式在甲状腺外科临床教学中的应用效果.方法 选择甲状腺外科临床实习的40名外科研究生作为研究对象,按照教学方式的不同分为实验组(A组)和对照组(B组),每组20名.A组采用...  相似文献   

10.
Macaques have been used as an important paradigm for understanding the neural control mechanisms of human precision grip capabilities. Therefore, we dissected the forearms and hands of two male Japanese macaques to systematically record the muscle mass, fascicle length and physiological cross-sectional area (PCSA). Comparisons of the mass fractions and PCSA fractions of the hand musculature among the Japanese macaque, chimpanzee, and human demonstrated that the sizes of the thenar and hypothenar eminence muscle groups are more balanced in the macaque and chimpanzee, but those of the thenar eminence group are much larger in the human, indicating that the capacity to generate force at the tip of the thumb is more restricted in macaques, despite their high manual dexterity. In the macaque, however, the extrinsic flexor muscles are much larger, possibly to facilitate weight bearing by the forelimbs in pronograde quadrupedal locomotion and forceful grasping of arboreal supports in gap-crossing movements such as leaping. Taking such anatomical differences imposed on the hand musculoskeletal system into consideration seems to be an important method of clarifying the mechanisms of precision grip in macaques.  相似文献   

11.
The eye-hand span (EHS) is the separation between eye position and hand position when sight-reading music. It can be measured in two ways: in notes (the number of notes between hand and eye; the 'note index'), or in time (the length of time between fixation and performance; the 'time index'). The EHSs of amateur and professional pianists were compared while they sight-read music. The professionals showed significantly larger note indexes than the amateurs (approximately four notes, compared to two notes), and all subjects showed similar variability in the note index. Surprisingly, the different groups of pianists showed almost identical mean time indexes (ca. 1 s), with no significant differences between any of the skill levels. However, professionals did show significantly less variation than the amateurs. The time index was significantly affected by the performance tempo: when fast tempos were imposed on performance, all subjects showed a reduction in the time index (to ca. 0.7 s), and slow tempos increased the time index (to ca. 1.3 s). This means that the length of time that information is stored in the buffer is related to performance tempo rather than ability, but that professionals can fit more information into their buffers.  相似文献   

12.
I engage debates about racial media bias by analysing newspaper coverage of professional tennis players in France and the United States. Tennis is an elite sport that typically does not have many non-white players and may be especially sensitive to racial boundaries. Tennis also offers a new solution to the methodological challenge of establishing that any difference in newspaper coverage across racial groups is due to bias and not actual differences across the groups. I use the professional tennis ranking system, which assigns an objective marker of how good a player is (and therefore the media coverage that s/he should receive) at any point in time. I explore two types of bias (the amount and tone of media coverage) and uncover no systematic racial differences in the relationship between ranking and media coverage. My findings have several implications for our understanding of racial boundaries and the media.  相似文献   

13.
Physical exercise and the training effects of repeated practice of skills over an extended period of time may have additive effects on brain networks and functions. Various motor skills and attentional styles can be developed by athletes engaged in different sports. In this study, the effects of fast ball sports and dance training on attention were investigated by event related potentials (ERP). ERP were recorded in auditory and visual tasks in professional dancer, professional fast ball sports athlete (FBSA) and healthy control volunteer groups consisting of twelve subjects each. In the auditory task both dancer and FBSA groups have faster N200 (N2) and P300 (P3) latencies than the controls. In the visual task FBSA have faster latencies of P3 than the dancers and controls. They also have higher P100 (P1) amplitudes to non-target stimuli than the dancers and controls. On the other hand, dancers have faster latencies of P1 and higher N100 (N1) amplitude to non-target stimuli and they also have higher P3 amplitudes than the FBSA and controls. Overall exercise has positive effects on cognitive processing speed as reflected on the faster auditory N2 and P3 latencies. However, FBSA and dancers differed on attentional styles in the visual task. Dancers displayed predominantly endogenous/top down features reflected by increased N1 and P3 amplitudes, decreased P1 amplitude and shorter P1 latency. On the other hand, FBSA showed predominantly exogenous/bottom up processes revealed by increased P1 amplitude. The controls were in between the two groups.  相似文献   

14.
We evaluated the asymmetric hand measurements in right- and left-handed individuals. 343 men and 290 women aged 18-42 years (22.11 +/- 2.07) participated in the study. There were no statistically significant differences when right-left differences in hand length, third finger length, palmar length, and the digit index value were evaluated according to hand preference and sex. Statistically significant differences were found for right-left differences in hand width, hand-shape index, and the palmar length/width according to hand preference. The strong left-handers, weak left-handers, and ambidextrous individuals in the study group all exhibited asymmetry favoring the left and were considered together. Similarly, the strong and weak right-handers exhibited asymmetry favoring the right hand and were considered together. The difference between these two groups was significant. When the data were evaluated according to sex, significant differences were found between the subgroups. In particular, right-left differences in the hand-shape index and palmar length/width values of the strong left-handers, weak left-handers, and ambidextrous individuals were found to be statistically significant according to sex; in contrast, the strong and weak right-handers showed no significant differences according to sex. These results suggest a relation of hand asymmetry to hand preference in a Turkish population.  相似文献   

15.
In 926 children (7 age groups) combined group differences of the signs have been studied by means of a unified standardized method, using the hand length as a linear measure; the conformity index to definitive size has been applied. For newborns proportional discrepancy to the definitive sizes is specific. They have a relatively long, thick and round body, short extremities, large dimensions of the head and abundant adipose subcutaneous deposits. According to the constitutional peculiarities the newborns resemble the children of the digestive type in mature persons--pycnotic or endomorphic. Beginning from birth, including children of early and first childhood (4-7 years of age), age changes of complexion go in two directions: a) dolichomorphy of complexion is realized; for it decreasing diameters of the chest and dimensions of the neck, chest, abdomen, pelvis (in boys), shoulder, arm, hand, foot and decrease in the subcutaneous adipose tissue are specific; b) longitudinal proportions of body and extremity segments change under influence of biomechanical adaptations to physical loads in connection with adaptation to the vertical position.  相似文献   

16.
Data on serum protein levels in Binga Pygmies are presented, and these are compared with the levels in healthy Italians and in Italians suffering from liver diseases. Principal Component Analysis carried out on the three groups points out similarities in protein levels between the Pygmies and the Italian Hepatopaths on one hand and between healthy and liver diseased Italians on the other. Discriminant Analyses reveal the important differences between the populations. It is suggested that such analyses of protein levels could serve as tools in population biology.  相似文献   

17.
The primate fossil record suggests that terrestriality was more common in the past than it is today, particularly among cercopithecoid primates. Whether or not a fossil primate habitually preferred terrestrial substrates has typically been inferred from its forelimb anatomy. Because extant large-bodied terrestrial cercopithecine monkeys utilize digitigrade hand postures during locomotion, being able to identify if a fossil primate habitually adopted digitigrade postures would be particularly revealing of terrestriality in this group. This paper examines the functional morphology of metacarpals in order to identify osteological correlates of digitigrade versus palmigrade hand postures. Linear measurements were obtained from 324 individuals belonging to digitigrade and palmigrade cercopithecoid species and comparisons were made between hand posture groups. Digitigrade taxa have shorter metacarpals, relative to both body mass and humerus length, than palmigrade taxa. Also, digitigrade taxa tend to have metacarpals with smaller dorsoventral diameters, relative to the product of body mass and metacarpal length, compared to palmigrade taxa. The size and shape of the metacarpal heads do not significantly differ between hand posture groups. Multivariate analyses suggest that metacarpal shape can only weakly discriminate between hand posture groups. In general, while there are some morphological differences in the metacarpals between hand posture groups, similarities also exist that are likely related to the fact that even digitigrade cercopithecoids can adopt palmigrade hand postures in different situations (e.g., terrestrial running, arboreal locomotion), and/or that the functional demands of different hand postures are not reflected in all aspects of metacarpal morphology. Therefore, the lack of identifiable adaptations for specific hand postures in extant cercopithecoids makes it difficult to determine a preference for specific habitats from fossil primate hand bones.  相似文献   

18.
Aging of the population is a growing problem in all developed societies. The older people need more health and social services, and their life quality in there is getting more and more important. The study aimed at determining the characteristics of non-verbal communication of the older people living in old people's homes (OPH). The sample consisted of 267 residents of the OPH, aged 65-96 years, and 267 caregivers from randomly selected twenty-seven OPH. Three types of non-verbal communication were observed and analysed using univariate and multivariate statistical methods. In face expressions and head movements about 75% older people looked at the eyes of their caregivers, and about 60% were looking around, while laughing or pressing the lips together was rarely noticed. The differences between genders were not statistically significant while statistically significant differences among different age groups was observed in dropping the eyes (p = 0.004) and smiling (0.008). In hand gestures and trunk movements, majority of older people most often moved forwards and clenched fingers, while most rarely they stroked and caressed their caregivers. The differences between genders were statistically significant in leaning on the table (p = 0.001), and changing the position on the chair (0.013). Statistically significant differences among age groups were registered in leaning forwards (p = 0.006) and pointing to the others (p = 0.036). In different modes of speaking and paralinguistic signs almost 75% older people spoke normally, about 70% kept silent, while they rarely quarrelled. The differences between genders were not statistically significant while statistically significant differences among age groups was observed in persuasive speaking (p = 0.007). The present study showed that older people in OPH in Slovenia communicated significantly less frequently with hand gestures and trunk movements than with face expressions and head movements or different modes of speaking and paralinguistic signs. The caregivers should be aware of this and pay a lot of attention to these two groups of non-verbal expressions. Their importance should be constantly emphasized during the educational process of all kinds of health-care professionals as well.  相似文献   

19.
Studied influence of music of certain intensity on latency recognition of even and odd numbers with participation of the left and right hand accordingly. Music accompaniment decreased the latency recognition more pronounced with participation of the left hand that, apparently, is connected with activated influence of music on the right hemisphere at the people who are not professional musicians. Increase of efficiency of recognition in music accompaniment is considered as realisation of a principle of a dominant.  相似文献   

20.
对四川、云南尔苏人、木雅人、空格人、八甲人4个族群进行了6项不对称行为特征(扣手、利手、叠臂、利足、叠腿、起步)的调查,结果显示:1)4个族群中,仅尔苏人、木雅人、八甲人叠臂以L型出现率偏高以外,其余不对称行为特征均为R型出现率较高;2)4个族群6项不对称行为特征均不存在性别间差异,但木雅人、尔苏人与八甲人在扣手这一不对称行为特征上存在族群间差异,木雅人与空格人在叠臂这一不对称行为特征上存在族群间差异;3)统计分析了6项不对称行为特征之间的相关性,仅八甲人多数不对称行为特征之间存在相关性。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号