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1.
Subjective attractiveness ratings of facial portraits of women taken at the fertile phase of the menstrual cycle are higher than those of portraits of the same women taken during non‐fertile periods. As female faces tilted downward are rated as more attractive and female courtship behaviours change across the menstrual cycle, we investigated whether systematic downward tilt of women's faces during the fertile phase might be responsible for increased attractiveness ratings. In the original study (Proc. R. Soc. Lond. B, 271, 2004, S272), the fertile‐phase portrait of each woman was deemed more attractive in 56–62% of cases. When the portraits were reclassified by head pitch, the more downward‐tilted portrait was preferred in 64–73% of cases. The fertile‐phase portrait was no more likely to be the downward‐tilted one, however, suggesting that effects of fertility on attractiveness are not simply due to changes in head position. We also had these portraits rated (N = 130) for physical attractiveness and behavioural allure. Fertile‐phase portraits were rated as more physically attractive than non‐fertile portraits, while more downward‐tilted portraits were rated as more behaviourally alluring than less downward‐tilted ones. These data not only confirm reported effects of head tilt and fertility on perceived female attractiveness, but also suggest that these factors influence different components of the attractiveness percept.  相似文献   

2.
The problem of representation is profound for anthropology: how do representation and represented relate? What motivates or warrants bridges over the inevitable disconnection between the two? I suggest that photographs and portraits provide a rich basis for thinking about the particular sorts of warrant for anthropological representation. My most general suggestion is that anthropological representation may be conceived of as a form of portraiture, and that it is an exercise in ekphrasis (a verbal account or evocation of a typically non-present image or object). Portraits need social conventions (such as a name in the caption) to be taken as such; representation is a three-part relationship between object, image and society. Cases from Cameroonian studio photography and a portrait of Marilyn Strathern exemplify the argument.  相似文献   

3.
This research attempts to answer the question how the change of selected face elements influences the likeness between the original portrait (sketch) and its modified versions. For this purpose, several series of portraits were created into which changes to the original sizes of eyes, mouth and nose within a scope of +/-14% (every 2%) were introduced. The task for a subject consisted of indicating one portrait out of each row that was the first to be "clearly unlike the original image". In this way, two values were obtained for each feature (lesser and greater than the initial one). These values have been called "the terminal values", i.e. those which, according to the subjects, once exceeded, the portrait becomes unlike the original. The results obtained indicate that the majority of the subjects, as much as 61.7%, consider the face they observe to be "clearly different" when the change of the studied features amounts to at least 8% of the original value, or even 6% in some cases. In addition, it has been noticed that, in the process of identification, men much earlier than women (p=0.049) consider the portraits in the row with the reduction of eye size unlike the original image.  相似文献   

4.
The participation of different afferent systems in organization of internal reference frame was studied. For this was chosen the task of visual comparison that executed in different experimental conditions: in upright standing, with inclined body or head in frontal plane and availability or non-availability visual information about external environment. Results showed that dominant orientation of referent stimulus (minimal value of mean error and minimal variability of responses) was connected with body position, mainly head position but not with gravity and visual vertical even when visual environment was available. It means that for creating the internal representing of vertical CNS mainly uses proprioceptive information about longitudinal axis of body.  相似文献   

5.
It has often been suggested that innate features of the human mind could make some cultural forms more successful than others. This paper presents a case study consistent with this “cognitive attraction” hypothesis. Numerous studies show that direct eye-gaze catches the attention of adults and newborns. Adults find it more attractive. We explore one possible cultural consequence of this cognitive appeal. Among XVIth century European portraits, direct-gaze paintings are more likely to be featured in today's art books. In Renaissance Europe, the proportion of paintings that stare at the viewer grows gradually, strongly, and remains prevalent for centuries. A demographic analysis of this shift shows that it was due to the arrival of new generations of painters. Those artists show a preference for direct-gaze portraits as soon as they start painting, suggesting that they acquired the new style in the years of their apprenticeship. The preferences of those painters and of contemporary art critics seem consistent with the innate attentional bias that favours direct-gaze faces. The structure of the “Renaissance gaze shift” bears evidence for the importance of demographic turn-over in cultural change.  相似文献   

6.
We have encountered an unexpected property of rRNA secondary structures that may generalize to all RNAs. Analysis of 8892 ribosomal RNA sequences and structures from a wide range of species revealed unexpected universal compositional trends. First, different categories of rRNA secondary structure (stems, loops, bulges, and junctions) have distinct, characteristic base compositions. Second, the observed patterns of variation are similar among sequences from large and small rRNA subunits and all domains of life, despite extensive evolutionary divergence. Surprisingly, these differences do not seem to be related to selection for different compositions in different structural categories, but rather relate to the overall composition of the molecule: Randomized RNAs with no evolutionary history show the same structure-dependent compositional biases as rRNAs. These compositional trends may improve the accuracy of RNA secondary structure prediction, because they allow us to compare predicted structures against known compositional preferences. They also suggest caution in interpreting differences in the rate of change of the GC content in different parts of the molecule as evidence of differential selection.  相似文献   

7.
Laterality of expression in portraiture: putting your best cheek forward.   总被引:3,自引:0,他引:3  
Portraits, both photographic and painted, are often produced with more of one side of the face showing than the other. Typically, the left side of the face is overrepresented, with the head turned slightly to the sitter''s right. This leftward bias is weaker for painted male portraits and non-existent for portraits of scientists from the Royal Society. What mechanism might account for this bias? Examination of portraits painted by left- and right-handers and of self-portraits suggests that the bias is not determined by a mechanical preference of the artist or by the viewer''s aesthetics. The leftward bias seems to be determined by the sitters and their desire to display the left side of their face, which is controlled by the emotive, right cerebral hemisphere. When we asked people to portray as much emotion as possible when posing for a family portrait, they tended to present the left side of their face. When asked to pose as scientists and avoid portraying emotion, participants tended to present their right side. The motivation to portray emotion, or conceal it, might explain why portraits of males show a reduced leftward bias, and also why portraits of scientists from the Royal Society show no leftward bias.  相似文献   

8.
Human body odour, symmetry and attractiveness.   总被引:13,自引:0,他引:13  
Several studies have found body and facial symmetry as well as attractiveness to be human mate choice criteria. These characteristics are presumed to signal developmental stability. Human body odour has been shown to influence female mate choice depending on the immune system, but the question of whether smell could signal general mate quality, as do other cues, was not addressed in previous studies. We compared ratings of body odour, attractiveness, and measurements of facial and body asymmetry of 16 male and 19 female subjects. Subjects wore a T-shirt for three consecutive nights under controlled conditions. Opposite-sex raters judged the odour of the T-shirts and another group evaluated portraits of the subjects for attractiveness. We measured seven bilateral traits of the subject's body to assess body asymmetry. Facial asymmetry was examined by distance measurements of portrait photographs. The results showed a significant positive correlation between facial attractiveness and sexiness of body odour for female subjects. We found positive relationships between body odour and attractiveness and negative ones between smell and body asymmetry for males only if female odour raters were in the most fertile phase of their menstrual cycle. The outcomes are discussed in the light of different male and female reproductive strategies.  相似文献   

9.
Summary Tethered flies were subjected to accelerations about their vertical axes while flying or walking. These accelerations were applied either suddenly to stationary animals or continuously by oscillating the animal from side to side. Head and wing movements resulting from the imposed angular accelerations were photographed with a camera and a stroboscopic flash.Analysis of the photographs shows that the wing movements act to counter the imposed angular accelerations and that during sinusoidal oscillations about the vertical axis, head turns are in antiphase with angular acceleration.Head turns do not occur when the halteres are absent or present and not oscillating. When oscillating, the halteres detect high values of angular acceleration, outside the known capabilities of the visual movement detection system.  相似文献   

10.
A close examination of the hands of people depicted in paintings of the Flemish school showed that in five paintings there were figures with hand lesions resembling those of rhematoid arthritis. Although none of the deformities or swellings are indisputable examples of rheumatoid arthritis, they do at least suggest that the painters must have been confronted with rheumatoid-like lesions in their models. In two other paintings there were signs of rheumatic fever and of temporal arteritis. No arthritic lesions were found in the works of painters of the Italian Renaissance, probably because they are less detailed. The finding of rheumatoid deformities in the Flemish paintings does, however, question the general belief that rheumatoid arthritis is a condition that has arisen relatively recently.  相似文献   

11.
This report deals with the study of compositional properties of human gene sequences evaluating similarities and differences among functionally distinct sectors of the gene independently of the reading frame. To retrieve the compositional information of DNA, we present a neighbor base dependent coding system in which the alphabet of 64 letters (DNA triplets) is compressed to an alphabet of 14 letters here termed triplet composons. The triplets containing the same set of distinct bases in whatever order and number form a triplet composon. The reading of the DNA sequence is performed starting at any letter of the initial triplet and then moving, triplet-to-triplet, until the end of the sequence. The readings were made in an overlapping way along the length of the sequences. The analysis of the compositional content in terms of the composon usage frequencies of the gene sequences shows that: (i) the compositional content of the sequences is far from that of random sequences, even in the case of non-protein coding sequences; (ii) coding sequences can be classified as components of compositional clusters; and (iii) intron sequences in a cluster have the same composon usage frequencies, even as their base composition differs notably from that of their home coding sequences. A comparison of the composon usage frequencies between human and mouse homologous genes indicated that two clusters found in humans do not have their counterpart in mouse whereas the others clusters are stable in both species with respect to their composon usage frequencies in both coding and noncoding sequences.  相似文献   

12.
The roles of different afferent systems in the organization of an internal reference frame was studied. The task of visual comparison was performed by subjects under different experimental conditions: in the upright standing position and with the body or head inclined in the frontal plane and with the visual information about an external environment available or not available. It was shown that the dominant orientation of a referent stimulus (the minimum value of the mean error in the reproduction of the stimulus and the minimal variability of the error) was correlated with the body position, mainly the position of the head, more than with the gravitational or visual vertical, even when the visual information was available. This means that the proprioceptive information about the longitudinal axis of body, rather than gravity, is mainly used by the central nervous system for creating the internal representing of vertical during standing.  相似文献   

13.
The effect of muscular fatigue on temporal and spectral features of muscle activities and motor performance, i.e., kinematics and kinetics, has been studied. It is of value to quantify fatigue related kinematic changes in biomechanics and sport sciences using simple measurements of joint angles. In this work, a new approach was introduced to extract kinematic changes from 2D phase portraits to study the fatigue adaptation patterns of subjects performing elbow repetitive movement. This new methodology was used to test the effect of load and repetition rate on the temporal changes of an elbow phase portrait during a dynamic iso-inertial fatiguing task. The local flow variation concept, which quantifies the trajectory shifts in the state space, was used to track the kinematic changes of an elbow repetitive fatiguing task in four conditions (two loads and two repetition rates). Temporal kinematic changes due to muscular fatigue were measured as regional curves for various regions of the phase portrait and were also expressed as a single curve to describe the total drift behavior of trajectories due to fatigue. Finally, the effect of load and repetition rate on the complexity of kinematic changes, measured by permutation entropy, was tested using analysis of variance with repeated measure design. Statistical analysis showed that kinematic changes fluctuated more (showed more complexity) under higher loads (p=0.014), but did not differ under high and low repetition rates (p=0.583). Using the proposed method, new features for complexity of kinematic changes could be obtained from phase portraits. The local changes of trajectories in epochs of time reflected the temporal kinematic changes in various regions of the phase portrait, which can be used for qualitative and quantitative assessment of fatigue adaptation of subjects and evaluation of the influence of task conditions (e.g., load and repetition rate) on kinematic changes.  相似文献   

14.

于倩    谢宗强    熊高明  陈志刚  杨敬元

《生态学报》2008,28(5):1931-1931~1941
采用样方法对神农架自然保护区巴山冷杉林的群落组成、优势种群结构与动态进行了研究.结果表明,该群落具有明显的温带常绿针叶林特征,以中小型革质、单叶的常绿高位芽植物为主.群落成层现象明显,可划分为乔木层、灌木层和草本层,林下苔藓层发达.植物的科属组成较为分散,乔木层主要优势科有松科(Pinaceae)、桦木科(Betulaceae)、杜鹃花科(Ericaceae)、槭树科(Aceraceae)等.区系成分复杂分散,与温带植物区系关系密切.巴山冷杉是该群落的建群种,重要值达54.30%,幼苗储备丰富,占更新层的90.4%,但幼树缺失.巴山冷杉中小径级个体占多数(78.8%),为进展型种群.高度结构基本呈倒金字塔形,集中分布于8~10级3个高度级上(62.2%),10级个体最多,占29.3%.植株个体数随冠幅级的递增呈倒"J"形分布,冠幅小于20m2的植株占87.4%,其中5m2以下最多(30.8%).冠幅与胸径呈指数相关,回归方程为y=2.7118e0.0308x,R2=0.520,冠幅与胸径的关系比与树高更密切.  相似文献   

15.
Yu Q  Xie Z Q  Xiong G M  Chen Z G  Yang J Y 《农业工程》2008,28(5):1931-1941
In this paper, the community composition of Abies fargesii and the population structure of dominant species in this community were studied using a sampling plot method. The research plot was located in Shennongjia National Nature Reserve, China. Results showed that the appearance of the community was characterized by evergreen phanerophytes with microphyllous (or mesophyllous), coriaceous and single leaves. The vertical structure of the community can be clearly divided into 4 layers: arbor layer, shrub layer, herb layer and developed moss layer. Abies fargesii population was a developing population as there were more seedlings and young trees than old trees. Saplings were found more frequently in gaps than under the close canopy, which indicated a pattern of gap regeneration. The height structure of Abies fargesii population presented a reversed pyramid shape. Crown size structure of the population showed a typical reversed J shape. The relation between crown size and DBH (diameter at breast height) was closer than that between crown size and height.  相似文献   

16.
李强  葛琴雅  潘晓轩  王宇  朱旭东  郭宏  潘皎 《生态学报》2014,34(6):1371-1378
古代岩画和壁画是人类文明发展历史进程的重要记录,具有极高的历史价值、艺术价值及科学价值,但他们无时无刻不受到环境因素引起的物理、化学及生物的劣化作用。近年,有关微生物对古代岩/壁画的危害逐渐受到关注。阐述了世界一些著名的岩/壁画文物的微生物的研究进展,如法国拉斯科洞穴岩画(Lascaux Cave)、西班牙阿尔塔米拉洞穴岩画(Altamira Cave)、敦煌石窟壁画、嘉峪关魏晋墓壁画以及我国东北地区公元5世纪的墓葬壁画等。通过对以上所述岩画和壁画微生物群落的分析比较,发现主要的细菌群落是变形菌门和放线菌门,放线菌门以假诺卡氏菌为主。真菌群落主要以虫生真菌为主。进一步分析了岩画和壁画微生物病害的共性和区别,揭示了洞穴、墓室等特殊环境下的微生物群落特点,为防治古代岩/壁画微生物病害提供了以下借鉴。  相似文献   

17.
During the rut, polygynous ungulates gather in mixed groups of individuals of different sex and age. Group social composition, which may vary on a daily basis, is likely to have strong influences on individual’s time-budget, with emerging properties at the group-level. To date, few studies have considered the influence of group composition on male and female behavioral time budget in mating groups. Focusing on a wild population of Alpine ibex, we investigated the influence of group composition (adult sex ratio, the proportion of dominant to subordinate males, and group size) on three behavioral axes obtained by Principal Components Analysis, describing male and female group time-budget. For both sexes, the first behavioral axis discerned a trade-off between grazing and standing/vigilance behavior. In females, group vigilance behavior increased with increasingly male-biased sex ratio, whereas in males, the effect of adult sex ratio on standing/vigilance behavior depended on the relative proportion of dominant males in the mating group. The second axis characterized courtship and male-male agonistic behavior in males, and moving and male-directed agonistic behavior in females. Mating group composition did not substantially influence this axis in males. However, moving and male-directed agonistic behavior increased at highly biased sex ratios (quadratic effect) in females. Finally, the third axis highlighted a trade-off between moving and lying behavior in males, and distinguished moving and female-female agonistic behavior from lying behavior in females. For males, those behaviors were influenced by a complex interaction between group size and adult sex ratio, whereas in females, moving and female-female agonistic behaviors increased in a quadratic fashion at highly biased sex ratios, and also increased with increasing group size. Our results reveal complex behavioral trade-offs depending on group composition in the Alpine ibex, and emphasize the importance of social factors in influencing behavioral time-budgets of wild ungulates during the rut.  相似文献   

18.
In this study, we analysed the eye movements of flatfish for body tilting and compared with that of goldfish. The fish was fixed on the tilting table controlled by computer. The eye movements for body tilting along the different body axis were video-recorded. The vertical and torsional eye rotations were analysed frame by frame. In normal flatfish, vertical eye movement of left eye to leftward tilting was larger than that to rightward tilting. For head up or head down tilting, clear vertical eye movements were observed. On the other hand, torsional eye movements showed similar characteristics as goldfish. These results suggested that sacculus and lagena were important for otolith-ocular eye movements in flatfish.  相似文献   

19.
The three-domains tree, which depicts eukaryotes and archaebacteria as monophyletic sister groups, is the dominant model for early eukaryotic evolution. By contrast, the ‘eocyte hypothesis’, where eukaryotes are proposed to have originated from within the archaebacteria as sister to the Crenarchaeota (also called the eocytes), has been largely neglected in the literature. We have investigated support for these two competing hypotheses from molecular sequence data using methods that attempt to accommodate the across-site compositional heterogeneity and across-tree compositional and rate matrix heterogeneity that are manifest features of these data. When ribosomal RNA genes were analysed using standard methods that do not adequately model these kinds of heterogeneity, the three-domains tree was supported. However, this support was eroded or lost when composition-heterogeneous models were used, with concomitant increase in support for the eocyte tree for eukaryotic origins. Analysis of combined amino acid sequences from 41 protein-coding genes supported the eocyte tree, whether or not composition-heterogeneous models were used. The possible effects of substitutional saturation of our data were examined using simulation; these results suggested that saturation is delayed by among-site rate variation in the sequences, and that phylogenetic signal for ancient relationships is plausibly present in these data.  相似文献   

20.
We investigated the hypothesis that maritime climatic factors associated with summer fog and low cloud stratus (summer marine layer) help explain the compositional diversity of chaparral in the coast range of central California. We randomly sampled chaparral species composition in 0.1‐hectare plots along a coast‐to‐interior gradient. For each plot, climatic variables were estimated and soil samples were analyzed. We used Cluster Analysis and Principle Components Analysis to objectively categorize plots into climate zone groups. Climate variables, vegetation composition and various diversity measures were compared across climate zone groups using ANOVA and nonmetric multidimensional scaling. Differences in climatic variables that relate to summer moisture availability and winter freeze events explained the majority of variance in measured conditions and coincided with three chaparral assemblages: maritime (lowland coast where the summer marine layer was strongest), transition (upland coast with mild summer marine layer influence and greater winter precipitation), and interior sites that generally lacked late summer water availability from either source. Species turnover (β‐diversity) was higher among maritime and transition sites than interior sites. Coastal chaparral differs from interior chaparral in having a higher obligate seeder to facultative seeder (resprouter) ratio and by being dominated by various Arctostaphylos species as opposed to the interior dominant, Adenostoma fasciculatum. The maritime climate influence along the California central coast is associated with patterns of woody plant composition and β‐diversity among sites. Summer fog in coastal lowlands and higher winter precipitation in coastal uplands combine to lower late dry season water deficit in coastal chaparral and contribute to longer fire return intervals that are associated with obligate seeders and more local endemism. Soil nutrients are comparatively less important in explaining plant community composition, but heterogeneous azonal soils contribute to local endemism and promote isolated chaparral patches within the dominant forest vegetation along the coast.  相似文献   

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