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Whole blood serotonin (WBS) determinations were made in 56 pigtailed macaques (Macaca nemestrina) with approximately equal numbers in three age groups: young-adult (4–5 years), middle-aged (13–14 years), and old (over 18 years). The animals were housed in ten living groups with one female and male of each age group in each living group. Half of the groups were fed a diet high in lipid, cholesterol, simple sugars, and sodium; the other half received a restricted diet. Three determinations per animal showed WBS levels to be stable at two times of day and at a 1-week interval, and individual differences were stable over several months' time. The mean WBS concentrations in M. nemestrina were found to be considerably higher than those reported for other species. The mean levels in females were almost 25% higher than in males. No significant effects of age, diet, or dominance status were detected.  相似文献   

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The interest shown by ecologists in antioxidants and oxidative stress as potential modulators of life‐history trade‐offs has expanded greatly in recent years. However, we still know very little about natural variation in oxidative damage and antioxidant capacity in free‐living animals. In this study, we describe the natural variation in three components of oxidative balance in nestlings and breeding females in free‐living Great Tits Parus major and Common Starlings Sturnus vulgaris in central Italy, and relate these to breeding conditions and life‐history traits. Our results suggest that there are associations among oxidative physiology, reproductive activity, growth pattern and season in wild birds, but that the nature of these associations might be species‐specific rather than general across species.  相似文献   

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Military medical information and data from civil registers of death and marriage have been used to study the role of physical characteristics and health conditions in explaining access to marriage for the male population of Alghero, a small city located in Sardinia Island (Italy), at the turn of 19th century. Literature data about contemporary populations have already demonstrated the influence of somatic traits in the mate choice. The results presented here show that men with low height and poor health status at the age of 20 were negatively selected for marriage. This holds true also in a society where families often arranged marriages for their children. This pattern of male selection on marriage was found to be particularly marked among the richest and wealthiest SES groups. Our hypothesis is that this social group carefully selected for marriage those individuals who were apparently healthier and therefore more likely to guarantee good health status and better life conditions to offspring. In evolutionary terms, the mate choice component of sexual selection suggests that the height of prospective partners could be claimed as one of the determinants, along with other environmental causes, of the observed higher stature of men belonging to the wealthiest social strata of the Alghero population. Am J Phys Anthropol, 2010. © 2009 Wiley‐Liss, Inc.  相似文献   

6.
《Small Ruminant Research》2009,85(1-3):82-88
In the present study the relationships between five body structural and nine udder morphological traits with milk yield and non-yield traits, i.e. milk contents, somatic cell count and body weight in n = 171 Frizarta ewes were investigated. Positive correlations of moderate to high magnitude were observed among body measurements ranging from 0.25 (body length-chest width) to 0.61 (chest width-chest girth). High correlations were observed between udder width and udder circumference (r = 0.69) as well as between udder circumference at base and middle (r = 0.62). Udder height was found to be positively correlated with cistern depth (r = 0.32), udder width (r = 0.40) and udder circumference (r = 0.42) as well as with teat measurements (0.19 and 0.25 with teat length and teat circumference, respectively). Cistern depth was positively and highly correlated with teat angle (r = 0.64). The correlation between teat length and circumference was also high (r = 0.57). Teat angle was found to be negatively correlated with teat measurements (r = −0.39 and −0.23 for teat length and teat circumference, respectively). Principal components analysis revealed four components that jointly explained 67% of the variance of all the body and the udder morphological traits. The first principal component interpreted as the body dimensions was found to be associated with body weight of ewes. The second component interpreted as global and rear measurements of the udder was significant for milk yield traits. The third and fourth principal components were interpreted as the udder type and teat dimensions, respectively. Ewes’ body weight could be adequately predicted by chest girth, body length, chest width and withers height. Test day milk yields were found to be associated with udder circumference and udder width as well as with udder height and teat length. None of the udder measurements and/or teat characteristics was found to be correlated with milk content(s) and/or somatic cell count. New statistical techniques can be successfully implemented in investigation of relationships between various traits in dairy sheep.  相似文献   

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Healthy adult volunteers (n = 122), who denied personal history of lung disease or family history of cystic fibrosis or asthma, took no interfering medications, and had forced expiratory volume in 1 s greater than or equal to 80% predicted, underwent methacholine challenge and pupillary reactivity testing. Pupil diameter measured in dark and light test conditions declined with age (Pearson's r = -0.54 and -0.36). Pupillary alpha-adrenergic responsiveness (expressed as the concentration of phenylephrine required to dilate the pupil 1 mm) was significantly correlated with age. Older subjects required lower concentrations for dilation and therefore were more sensitive to phenylephrine. Pupillary cholinergic responsiveness (the concentration of carbachol required for 1-mm constriction) was not significantly correlated with age. Therefore the significantly smaller baseline pupil size in the elderly cannot be explained by failure of alpha-adrenergic receptor responses or by increased pupillary cholinergic responsiveness. We found no significant correlation of methacholine bronchial reactivity with age. In addition, there was no relation between airway reactivity and pupillary alpha-adrenergic or cholinergic responsiveness in this sample of healthy adults. These findings, taken with others in the literature, suggest that the contribution of alpha-adrenergic and cholinergic responsiveness to nonspecific airway reactivity in healthy persons is small, if it exists at all, and that there is no significant change in airway reactivity with age in healthy adults.  相似文献   

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Clara de Vega  Carlos M. Herrera 《Oikos》2012,121(11):1878-1888
Nectar‐dwelling yeasts are emerging as widely distributed organisms playing a potentially significant and barely unexplored ecological role in plant pollinator mutualisms. Previous efforts at understanding nectar–pollinator–yeast interactions have focused on bee‐pollinated plants, while the importance of nectarivorous ants as vectors for yeast dispersal remains unexplored so far. Here we assess the abundance and composition of the nectar fungal microbiota of the ant‐pollinated plant Cytinus hypocistis, study whether yeast transmission is coupled with ant visitation, and discern whether ant‐ transported yeasts promote changes in nectar characteristics. Our results show that a high percentage of flowers (77%) and plants (94%) contained yeasts, with yeast cell density in nectar reaching up to 6.2 × 104 cells mm?3, being the highest densities associated with the presence of the nectar‐specialist yeast Metschnikowia reukaufii. The establishment of fungal microbiota in nectar required flower visitation by ants, with 70% of yeast species transported by them being also detected in nectar. Ant‐vectored yeasts diminished the nutritional quality of nectar, with flowers exposed to pollinators and yeasts containing significantly lower nectar sugar concentration than virgin flowers (13.4% and 22.8%, respectively). Nectar of flowers that harbored M. reukaufii showed the lowest quality, with nectar concentration declining significantly with increasing yeast density. Additionally, yeasts modified patterns of interpopulation variation in nectar traits, homo genizing differences between populations in some nectar attributes. We show for the first time that the outcome of the tripartite pollinator–flower–yeast interaction is highly dependent on the identity and inherent properties of the participants, even to the extent of influencing the species composition of this ternary system, and can be mediated by ecological characteristics of plant populations. Through their influence on plant functional traits, yeasts have the potential to alter nectar consumption, pollinator foraging behavior and ultimately plant reproduction.  相似文献   

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The status-signalling hypothesis has been proposed to explain colour variation among individuals in flocking birds. Its fundamental assumption is that colour may affect the determination of an individual's social rank in a flock. Here I show for winter Harris' sparrows (Zonotrichia querula) that birds dyed to resemble adults dominate control birds within experimental flocks of young males and young females. The domination of controls by the dyed birds was achieved by a two-step process in both experiments: immediately after the two groups were combined, the controls avoided the dyed birds; then, shortly thereafter, the dyed birds began actively to displace the control birds.  相似文献   

10.
  • 1.1. Serum concentrations of cholesterol, triglyceride and alpha lipoprotein cholesterol were determined in nine Holstein cows during different stages of their gestation and lactation cycles.
  • 2.2. Serum cholesterol concentrations and daily milk yields were significantly correlated during early and late lactation. The correlations were not significant over the entire lactation.
  • 3.3. Maximum values for serum cholesterol were observed at mid lactation and minimum at or near parturition. Serum triglyceride concentrations ranged from 4 to 33 mg/dl. Although prepartum levels for triglyceride tended to be higher than postpartum concentrations, no correlation with milk yield was noted.
  • 4.4. These data are compared with lipid changes which take place in other mammals during lactation.
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G.A.M. King 《Bio Systems》1982,15(2):89-97
Kinetic considerations make it most improbable that any reproducing system could arise spontaneously in a prebiotic soup containing a large variety of organic molecules, as commonly postulated. This batch process can be contrasted with a completely recycling network of reactions maintained by an influx of energy. So long as the network includes at least two bimolecular reactions it is likely to support pathways for chemical reproduction. However, such reproducing systems will be simple in both kinetic and structural terms. Subsequent evolution will lead to much more complex reproducing structures although the kinetic complexities, measuring the varieties of reactions between these structures and their media, will remain relatively simple.  相似文献   

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旨在研究3个地方鸡品种(汶上芦花鸡、莱芜黑鸡、济宁百日鸡)主要组织相容性复合体(Major Histocompatibility Complex,MHC) B-LBII基因遗传变异与绵羊红细胞(Sheep red blood cell,SRBC)、禽流感(Avian influenza,AI)和新城疫(Newcastle disease,ND)抗体滴度等免疫性状的关系,揭示不同品种间基因变异与免疫性状的相关性.以300只地方品种鸡为材料,运用直接测序和聚合酶链式反应-单链构象多态性(PCR-SSCP)等技术检测MHC B-L BⅡ基因的序列变异.在3个地方鸡品种中分别发现了19~22个核苷酸变异位点,可导致其中16~18个氨基酸的变异.3个地方鸡种MHC B-L BⅡ基因中分别有7~8个(Single nucleotide polymorphism,SNP)位点与部分免疫性状存在不同程度的显著相关性.变异位点G97A和T138A在3个品种中均存在,与SRBC、ND、AI抗体滴度均显著相关(P<0.05).其中,G97A突变在济宁百日鸡中与ND抗体滴度显著相关(P<0.05),在莱芜黑鸡中与SRBC抗体滴度显著相关(P<0.05),在汶上芦花鸡中与H9抗体滴度显著相关(P<0.05);变异位点T138A在汶上芦花鸡和济宁百日鸡中与H9抗体滴度显著相关(P<0.05).研究表明3个地方鸡种的MHC B-LBII基因遗传变异与免疫性状存在显著关联.  相似文献   

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This research tests the hypothesis that change over time in women’s status leads to improvements in their children’s health. Specifically, we examine whether change in resources and empowerment in mother’s roles as biological mothers, caregivers, and providers and social contexts that promote the rights and representation of and investment in women are associated with better nutritional status and survival of young children. Analysis is based on a broad sample of countries (n = 28), with data at two or more points in time to enable examination of change. Key indicators of child health show improvement in the last 13 years in developing nations. Much of this improvement—90 percent of the increase in nutritional status and 47 percent of the reduction in mortality—is associated with improving status of women. Increased maternal education, control over reproduction, freedom from violence, access to health care, legislation and enforcement of women’s rights, greater political representation, equality in the education system, and lower maternal mortality are improving children’s health. These results imply that further advancement of women’s position in society would be beneficial.  相似文献   

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Abstract

A study of males and their fathers representative of the nonfarm white population of Minnesota supports the hypothesis that social mobility is correlated with the discrepancies between the general intelligence of sons, as measured by IQ test scores, and the social class into which they were born. A multiple regression analysis performed on these data illustrates the independent contribution of intelligence to the variance in two achieved statuses, educational attainment and occupational level. The substantial correlation between father‐son difference in IQ score and father‐son difference in social position, and the relationship between the magnitude and direction of IQ score difference and the distance and direction of social mobility, both support the view that differences in ability provide a “springboard” that enables individuals to be socially mobile and that to some degree prevents social classes in an open society from congealing into castes.  相似文献   

16.
Slow bee paralysis virus (SBPV)—previously considered an obligate honeybee disease—is now known to be prevalent in bumblebee species. SBPV is highly virulent in honeybees in association with Varroa mites, but has been considered relatively benign otherwise. However, condition-dependent pathogens can appear asymptomatic under good, resource abundant conditions, and negative impacts on host fitness may only become apparent when under stressful or resource-limited conditions. We tested whether SBPV expresses condition-dependent virulence in its bumblebee host, Bombus terrestris, by orally inoculating bees with SBPV and recording longevity under satiated and starvation conditions. SBPV infection resulted in significant virulence under starvation conditions, with infected bees 1.6 times more likely to die at any given time point (a median of 2.3 h earlier than uninfected bees), whereas there was no effect under satiated conditions. This demonstrates clear condition-dependent virulence for SBPV in B. terrestris. Infections that appear asymptomatic in non-stressful laboratory assays may nevertheless have significant impacts under natural conditions in the wild. For multi-host pathogens such as SBPV, the use of sentinel host species in laboratory assays may further lead to the underestimation of pathogen impacts on other species in nature. In this case the impact of ‘honeybee viruses’ on wild pollinators may be underestimated, with detrimental effects on conservation and food security. Our results highlight the importance of multiple assays and multiple host species when testing for virulence, in order for laboratory studies to accurately inform conservation policy and mitigate disease impacts in wild pollinators.  相似文献   

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Studies of nonhuman primates indicate that social subordinance associates with chronic elevated cortisol, but this finding has not been replicated among humans. This topic was examined in a study of 31 healthy adult male Dominican villagers ages 17 to 49 years. Each subject's mean cortisol level was calculated using multiple time-standardized salivary cortisol samples (minimum = 6, mean = 14. 8 samples per subject) determined by radioimmunoassay. Semistructured ethnographic interviews were used to collect several measures of social status. Data were analyzed with a backward stepwise multivariate linear regression model. Partial regression statistics revealed four significant associations with cortisol: (i) men with reputations for illicit social behavior had higher cortisol; (ii) men who reported more frequent distressed mood had higher cortisol; (iii) men rated as less trustworthy, agreeable, influential, and helpful by their peers had higher cortisol; and (iv) men whose fathers were absent as a childhood caretaker had higher cortisol. No associations were found between cortisol and (a) a composite of educational attainment, income, and material wealth; (b) frequency of tobacco consumption; (c) frequency of perceived social stressors; or (d) a composite of number of children and dependents.  相似文献   

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We studied the sibling similarity in development of covariation among body size characters (body weight (W), body length (S) and head circumference (HC) in Tel Aviv infants from birth up to 2 years of age. We investigated the effects of parental geographic origin, profession, age, current residence, and of family size. Multiple regression analysis with "dummy" procedure established that none of these variables had any significant effect on the aforementioned anthropometric traits. The matrices of phenotypic and genetic correlations, based on sibling similarity data, among age-specific W, S, and HC (measured for 12 different ages) were subjected to principal component analysis in order to elucidate patterns over the age groups. The patterns of both analyses, phenotypic and genetic, were quite similar: one factor in each (first genetic and second phenotypic) had a high positive correlation with early, first 2-3 months of life, W, S, and HC. Three other extracted factors correlated strongly, each with late W, S, and HC, respectively. The results of additional principal component analyses of age-specific W, S, and HC matrices separately, indicate the possibility of existence of two genetic subsystems, the first determining early postnatal stages of human ontogeny, and the second, later phases of child development.  相似文献   

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