Ethanol-induced sleeping time in mice: age and sex differences

Ethanol-induced sleeping time was determined in mice of both sexes at ages ranging from 3 weeks to just over 1 year. A progressive increase in sleeping time was seen in both sexes up to 26 weeks of age; no subsequent changes were observed, except for a modest decrease in the oldest female group. In the majority of age groups, sleeping time values were higher in females, but few statistically significant sex differences were found.     

Mate choice differences according to sex and age

We used 7,415 advertisements published in Spain to analyze traits sought/offered by men and women from different age groups. Findings regarding age, socioeconomic status, and physical attractiveness requirements support evolutionary predictions about mate preferences. However, changes in trait preferences among women under 40 appear to be contingent on Spain’s socioeconomic transformation. Women under 40 seek mainly physical attractiveness in men, whereas those over 40 seek mainly socioeconomic status. The trait most sought by men in all age groups is physical attractiveness. Traits sought and offered by advertisers may be conditioned by the personal situation of the advertiser. Mean age of advertisers (around their forties) and Spain’s social indicators suggest that the majority of advertisers have been unsuccessful in the mating arena at the conventional age.     

氯胺酮诱导不同年龄和性别小鼠的过度活动

虽然氯胺酮(Ketamine)在历史上作为麻醉剂用于人类和家畜,但由于其分解特性, 作为一种娱乐药物似乎更具知名度.以前的研究表明相对于成年人, 孩子使用氯胺酮不易显示出不利影响,但是对其发生的机理几乎没有研究.本文研究了氯胺酮对小鼠的活动程度和固有行为的作用.结果表明:使用氯胺酮可增加22、35和50日龄小鼠的运动器官的敏捷性,并证明了氯胺酮的作用随年龄的增长而降低;使用氯胺酮所导致的旋转与年龄的变化有关,但站立的减少与年龄无关,这种减少不依赖于小鼠的年龄.     

Bone size and mechanics at the femoral diaphysis across age and sex

The reasons for the increase in fracture rates with age are not fully understood. It is known that there is a decrease in bone mass with a presumed loss of strength. This decrease may possibly be compensated for by changes in cross-sectional geometry. Previous studies, which have been limited by lack of information on subjects’ heights and weights, were not able to resolve this issue. In this study, measurements of cross-sectional geometry (area and second moments of area) from 107 specimens of human femoral diaphysis from subjects aged 21–92 years were analysed. Mathematical models of the variation in bone geometry with age were developed. These models included the effects of sex, height and weight. Values of parameters from these models were then used in a biomechanical analysis of the static stresses at the mid-shaft of the femur. Results indicate that although there was a reduction in cortical area in old age, bone tissue was redistributed so that neither bending stresses in the coronal plane nor torsional stresses were higher in old age than in young adulthood. An additional finding was that at any age women had smaller bones, less cortical bone area and higher bone stresses than men. This finding may have some bearing on the higher fracture incidence seen in older women.     

Discontinuous traits of the skull: variations on sex, age, laterality

This paper discusses some problems relating to the study and the utilization of discontinuous traits in anthropology. The importance of sex, age and laterality in the manifestation of these traits is discussed on the basis of investigations on a numerous skeletal sample of Siena (Tuscany, Italy) and on data from literature. It is pointed out that sides and sexes should be considered separately. The age of adult subjects seems to be insignificant as the incidence of these traits is concerned.     

Iris heterochromia: variations in form, age changes, sex dimorphism]

On a sample of n = 25,346 individuals from Vienna (10,855 males, 14,491 females) the iris pigmentation has been typed by the author. In this sample 65 cases of different types of heterochromia were found. The frequency of the occurrence of the different types of this anomaly could be calculated for the first time. Neglecting age, sex, and type of heterochromia the total frequency amounts to 0.256 (males: 0.157; females: 0.37) %. The variants of heterochromia very from cases of total heterochromia to those of various size; in addition to it a number of special types could be observed. The localization of the heterochrome parts of the iris shows certain variations; mostly, however, it is seen in the lower half of the iris. The nasal part is concerned in only one case; the temporal region never. Thus, the partial heterochromia is characteristic by a marked dependency of its localization. The colour of heterochromia varies from 2 a-14 according to the Martin-Schultz standard set of coloured eyes. However, No. 9 (ca. 50%) and No. 7 (ca. 20%) were the most frequent colours. The age variations are considerable. 5/6 of all heterochromias were found between the age from 2-19 years. Finally, a marked sexual dimorphism was observed, as in females heterochromia is much more frequent than in males.     

Tear duct size differences of age, sex and race

Measurements of the external opening of the tear duct (naso-lachrymal canal) of skulls of American colored males and white males indicate larger apertures among the former at corresponding ages. Duct length is somewhat shorter among colored males. In both racial samples the older skulls have slightly larger apertures than those under 40. A sample of white female skulls corroborates this, and manifests smaller average size than the white male skulls at ages below 50 whereas older skulls reveal no sex difference. The race difference in aperture size among male skulls is highly significant statistically and may reflect ecological adaptation.     

Genetic analysis of the pinna of the human ear: sex differences in college age adults

Photographs of the left ears of 113 male and 197 female students of the University of Northern Colorado were taken using a 35mm camera with 50mm lens, small electronic flash, +4 close-up lens, and ASA 100 color film. Camera and flash attachment were mounted on a light metal frame positioning the camera 90 degrees to the head and a specific distance from the ear. Metric scale and counter were mounted so they were visible in the photograph. Eight vertical measures and eight horizontal measures were made, and 15 subjective-objective data taken. Means, variances, and interrelationships were determined. Mean height for males was approximately five inches greater than for females. Vertical measures were standardized by expressing ear/body height as a ratio. Three vertical measures--width of the superior helix, distance from superior helix to the edge of antihelix, and distance from antihelix to tip of the lobule--and three horizontal measures--width of the pinna, width of the posterior helix, and width of the notch--appear to be under specific genetic regulation in the two sexes.     

Advancing age produces sex differences in vasomotor kinetics during and after skeletal muscle contraction

Little is known of the vasomotor responses of skeletal muscle arterioles during and following muscle contraction. We hypothesized that aging leads to impaired arteriolar responses to muscle contraction and recovery. Nitric oxide (NO) availability, which is age dependent, has been implicated in components of these kinetics. Therefore, we also hypothesized that changes in the kinetics of vascular responses are associated with the NO pathway. Groups were young (3 mo), old (24 mo), endothelial NO synthase knockout (eNOS-/-), and N(G)-nitro-L-arginine (L-NA)-treated male and female C57BL/6 mice. The kinetics of vasodilation during and following 1 min of contractions of the gluteus maximus muscle were recorded in second-order (regional distribution) and third-order (local control) arterioles. Baseline, peak (during contraction), and maximal diameters (pharmacological) were not affected by age or sex. The kinetics of dilation and recovery were not different between males and females at the young age. There was a significant slowing of vasodilation at the onset of contractions (approximately 2-fold; P < 0.05) and a significant speeding of recovery ( approximately 5-fold; P < 0.05) in old males vs. old females and vs. young eNOS-/-, and L-NA did not affect the kinetics at the onset of muscle contraction. eNOS-/- mimicked the rapid recovery of old males in second-order arterioles; acute NO production (L-NA) explained approximately 50% of this effect. These data demonstrate fundamental age-related differences between the sexes in the dynamic function of skeletal muscle arterioles. Understanding how youthful function persists in females but not males may provide therapeutic insight into clinical interventions to maintain dynamic microvascular control of nutrient supply with age.     

Thiazide-induced hypercholesterolemia: sex differences

Thiazide diuretics are used commonly to treat hypertension. Unfortunately, they also are known to elevate serum cholesterol levels. Because serum lipid fraction levels differ between the sexes, possible sex-related differences in thiazide-induced changes in serum total cholesterol (TC), triglycerides (TG) and high density lipoprotein cholesterol (HDL-C) levels were examined. Four groups of male and female hamsters were treated for a minimum of 3 months with hydrochlorothiazide (HCTZ) at zero, 1, 2 or 4 mg/kg/day. At zero dose, there was no difference in TG levels between the sexes; however, females had significantly higher TG concentrations than did males at 1, 2 and 4 mg HCTZ (all p less than 0.05). Females demonstrate a significant dose response with HCL-C levels increasing with increasing doses of HCTZ, (r = 0.983; p less than 0.02); in contrast males had a similar increase in HDL-C at all dose levels (all p less than 0.05) thus there was no demonstrable dose response (r = 0.539). Total cholesterol concentrations were significantly higher in the females than in males (p less than 0.05) at all 3 dose levels as well as at zero dose. Further, the females demonstrated a direct dose response in TC levels (r = 0.986; p less than 0.02) while the males showed no such dose response (r = 0.824; p less than 0.01). Based on these findings we conclude that: 1) HCTZ increases TG, TC and HDL-C levels in both male and female hamsters; 2) TC levels are higher in females than in males regardless of HCTZ dose; 3) only females show a dose-dependent increase in HCL-C and TC in response to HCTZ. These sex-related changes in lipid fractions occurring with HCTZ treatment, if they occur in humans, may contribute to sex-related differences in rates and severity of atherosclerosis in HCTZ-treated populations.     

Concentrations of murinoglobulin and alpha-macroglobulin in the mouse serum: variations with age, sex, strain, and experimental inflammation

Serum levels of murinoglobulin and alpha-macroglobulin were low in newborn mice but increased during the prepubertal development. The adult levels of the two inhibitors were higher in males than in females in 8 inbred strains tested. Gonadectomy at 2 w of age did not significantly affect the prepubertal rise in the levels not only of the above two inhibitors but of contrapsin and alpha-1-antiprotease. The gonadectomy, however, abolished the sex differences seen in the adult levels of these inhibitors. The levels of murinoglobulin and alpha-macroglobulin reached their minimum at 12 h after inducing inflammation and returned to normal at 24 h. Little change was observed in the levels of contrapsin and alpha-1-antiprotease under the same inflammatory conditions.     

Sex differences in the Ilia of a known sex and age sample of fetal and infant Skeletons

Ilia from a known sex, race, and age sample of fetal and infant skeletons from the collections of the Smithsonian Institution were evaluated for six metric and one nonmetric characters. Three indices calculated from the measurements were analyzed. The nonmetric trait was examined for fit with known sex. The three indices failed to show significant sex differences. The nonmetric trait, Auricular Surface Elevation, proved dependable (91% accurate) for the male Fetal and Six Month age groups.     

Universal sex differences in online advertisers age preferences: comparing data from 14 cultures and 2 religious groups

The search for a potential partner has been aided over recent years by the widespread use of online dating sites and this process of relationship formation has conveniently presented an ideal opportunity for researchers to analyze human mating desires and to compare evolutionary and social constructivist based hypotheses. One such aspect of human mating behaviour yet to be thoroughly explored using access to online dating advertisements is the idealized age desired by each sex when considering a possible relationship. This study accessed minimum (youngest age considered) and maximum (oldest age considered) age preferences from 14 separate cultures and two religious groups from both sexes at ages 20, 25, 30, 35, 40, 45, and 50 years. The results showed that overall there was a growing disparity between males own age and preferred age of partner as males themselves aged (as indicated by greater effect sizes with advertisers age), with females showing a pattern for preferences around their own age or older. Females did not express an age preference for males younger than male's age preferences for females at any advertiser's age. On only three occasions were there no age differences between the sexes in their desire to initiate a relationship with the opposite sex. The results were clearly concurrent with earlier findings supportive of evolutionary or adaptationist interpretations. Neither a random pattern of age preferences more consistent with an arbitrary norms prediction, nor clear evidence for toy boy proclivities in females or males was found. Future studies utilizing the methodology used in this study to examine other human mating decision making processes are proposed.     

Spinal and cortical potentials evoked by tibial nerve stimulation in humans: effects of sex, age and height.

Somatosensory evoked potentials by posterior tibial nerve stimulation at the ankle were performed in 74 healthy volunteers (36 females and 38 males) aged 14-76 years. Cortical potentials were obtained in all subjects and spinal potentials (N22) in 71 subjects. All parameters were related to subject's age, height and sex. Sex influenced only P40-N50 amplitude, which was greater in females. All latencies of spinal and cortical components increased in a similar manner with subject's height (about 0.16-0.18 ms per cm), whereas the N22-P40 interpeak latency was independent from height, but related to T12-Cz distance. Absolute latencies of the spinal and of most cortical components, but not interpeak latencies, increased with subject's age (about 0.06-0.09 ms per year). The parameters to compute normative data (according to univariate or bivariate regression models) are furnished. Limits of right-left differences are reported.     

Effects of sexual differences of age at maturity and survival on population sex ratio

Summary Five demographical factors influencing the sex ratio of a population are classically considered. The influence of two of them is dependent on the longevity of individuals in the population. The effect of differential age at maturity between males and females is higher for animals with low annual survival, whereas the effect of differential annual survival between males and females is higher for animals with high annual survival. Such a conclusion applied to turtles, which are long life-span animals, allows us to retain differential survival between sexes as a major factor influencing the population sex ratio.