16 resultados para Sexual paradigm
em Chinese Academy of Sciences Institutional Repositories Grid Portal
Resumo:
Endogenous retroviruses ( ERVs) are remnants of ancient retroviral infections of the host germline transmitted vertically from generation to generation. It is hypothesized that some ERVs are used by the host as restriction factors to block the infection o
Resumo:
Repeated vivid recalls or flashbacks of traumatic memories and memory deficits are the cardinal features of post-traumatic stress disorder (PTSD). The underlying mechanisms are not fully understood yet. Here, we examined the effects of very strong fear conditioning (20 pairings of a light with a 1.5-mA, 0.5-s foot shock) and subsequent reexposure to the conditioning context (chamber A), a similar context (chamber B), and/or to the fear conditioned stimulus (CS) (a light) on synaptic plasticity in the hippocampal CA1 area in anesthetized Sprague-Dawley rats. The conditioning procedure resulted in very strong conditioned fear, as reflected by high levels of persistent freezing, to both the contexts and to the CS, 24 h after fear conditioning. The induction of long-term potentiation ON was blocked immediately after fear conditioning. It was still markedly impaired 24 h after fear conditioning; reexposure to the conditioning chamber A (CA) or to a similar chamber 13 (CB) did not affect the impairment. However, presentation of the CS in the CA exacerbated the impairment of LTP, whereas the CS presentation in a CB ameliorated the impairment so that LTP induction did not differ from that of control groups. The induction of long-term depression (LTD) was facilitated immediately, but not 24 h, after fear conditioning. Only reexposure to the CS in the CA, but not reexposure to either chamber A or B alone, or the CS in chamber B, 24 h after conditioning, reinstated the facilitation of LTD induction. These data demonstrate that unconditioned and conditioned aversive stimuli in an intense fear conditioning paradigm can have profound effects on hippocampal synaptic plasticity, which may aid to understand the mechanisms underlying impairments of hippocampus-dependent memory by stress or in PTSD. (c) 2005 Wiley-Liss, Inc.
Resumo:
Traumatic events always lead to aversive emotional memory, i.e., fear memory. In contrast, positive events in daily life such as sex experiences seem to reduce aversive memory after aversive events. Thus, we hypothesized that post-traumatic pleasurable ex
Resumo:
Data on sexual behavior were collected in six groups of semi-commensal Macaca thibetana along the trail on the slope habitat between 1987 and 1989. Ignoring the common items such as mounting, presenting etc., 20 categories of sexual behavior were described. Most of the descriptions were likely to have enlarged the behavior repertoire reported in macaques, showing a great complexity of sociosexual interactions under the principally natural condition. A great diversity of grouping appeared in the mating season. The copulatory pattern was found to be the serial type contrary to previous speculation, and the mount-to-ejaculation ratio was higher in the central subgroup, as compared with the far-peripheral adult subgroup (FAS) with less male and female rivals. An age-class subdivision of sexually active males made it possible to show that the young adult male immigrants were the most active class in sexual activity. Subgrouping form FAS was a ''space-segregation'' tactic of mating for the losers of both sexes in the competition. Some parameters of copulation were also documented.
Resumo:
Sexual dimorphism in the dentition and skeleton of the four extant species of snub-nosed langurs, Rhinopithecus (R.) bieti, R. (R.) brelichi, R. (R.) roxellana and R. (Presbytiscus) avunculus, was studied. The species shared a similar general pattern of sexual dimorphism, but were found to differ in respects that appear to reflect the influence of disparate socioecological and environmental factors. All the species showed marked canine dimorphism, but the very high degree of canine dimorphism in R. bieti appeared to be due to the intensity of intermale competition for mates during a temporally restricted breeding season, and possibly also to the intensity of competition between males for other resources during other times of the year. Sexual dimorphism in the postcranial skeleton of Rhinopithecus species was also most pronounced in R. bieti and may be related to the relatively higher frequency of terrestrial locomotion in males of the species. (C) 1995 Wiley-Liss, Inc.
Resumo:
The effect of distance between members of pairs of the Ruddy Shelduck (Tadorna ferruginea) during vigilance behavior was studied during winter at Lijiang Lashihai Lake Reserve, southwest China. The distance between the paired birds while feeding was grouped into three categories: <1 m, 1-3 to and >3 m. Nearly 90% of the distances recorded between paired males and females were within three meters. The degree of vigilance increased with distance apart for females, but not for males. The scanning rate of males was significantly, higher than that of females at <1 m and at 1-3 m respectively, but no significant difference occurred when the distance between them was >3 m. These results are discussed in relation to mate competition and wintering strategy; it is suggested that staving close together is the optimal strategy for members of Ruddy Shelduck pairs.
Resumo:
Data regarding the sexual behavior of black-and-white snub-nosed monkeys (Rhinopithecus bieti) were collected in 1998 in a one-male unit in captivity by all-occurrences sampling during the mating season. Before the present study, little was known about the sexual behavior of this species. This study showed that female solicitation is mainly expressed as "prostration plus glancing laterally" (PG) or "sitting plus head moving up and down" (HM), and male solicitation is exhibited by the "grunt bared-teeth display." The mount-to-ejaculation ratio was 5.2 on average, and single-mount ejaculations (SMEs) were observed in only 4.4% of mounts on days with at least one ejaculation. Therefore, the main copulatory pattern of this species is multiple-mount ejaculation (MME). Females initiated 72% of 18 ejaculatory mounts. Females initiated more ejaculatory mounts than non-ejaculatory ones. In general, the patterns of sexual behavior in this species are similar to those reported for other Colobines. (C) 2004 Wiley-Liss, Inc.
Resumo:
A method was presented for the determination of testosterone, methyltestosterone and progesterone in liquid cosmetics by coupling polymer monolith microextraction (PMME) to high performance liquid chromatography with UV detection. A poly (methacrylic acid-ethylene glycol dimethacrylate) monolithic capillary column was selected as the extraction medium, which showed high extraction capacity towards these compounds. To achieve optimum extraction performance, several parameters relating to PMME were investigated, including extraction flow rate and pH value, inorganic salt and organic phase concentration of the sample matrix. By simple dilution with phosphate solution and filtering, the sample solution then could be directly injected into the device for extraction. The limits of detection of testosterone, methyltestosterone and progesterone were calculated to be 2, 3, 2, 8 and 4.6 mu g/L. Good linearity was achieved in the range of 10 to 1000 mu g/L with a linear coefficient. r value above 0. 996. Excellent method reproducibility was found by intra- and inter-day precisions, yielding the relative standard deviations of < 7. 7 % and < 7. 5 %, respectively. Recovery for them in the real samples was between 83% and 119%.
Resumo:
The sexual ratio of Gobiocypris rarus exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 17 beta -estradiol from embryo to sexually mature revealed feminization and overdevelopment of connective tissue in male fish gonad in 2-30 pg/L TCDD concentration range. Daphnia magna was not sensitive to the high dose of TCDD (0.1-1000 ng/ml), but the reproduction of D. magna treated with TCDD decreased after the 8th day. 7-Ethoxyresorufin-O-deethylase (EROD) activities in newly fertilized eggs of G. rarus exposed to TCDD dosage groups (1000-100,000 pg/L) were significantly induced and increased with TCDD concentrations at the early life stage, while no difference was found between low TCDD dosage groups (<100 pg/L), but a good relationship between the EROD activity and the TCDD concentration was observed during a long-term developmental stage. There was a pericardial edema formed in a 2-week yolk-sac at the concentration of 1000 pg/L TCDD. But in the exposure group (2 pg/L TCDD for 120 days), the cell nuclei of hepatocytes was far from the center and packed toward the cell membrane; the cristae of most mitochondria in the cell dropped and collapsed; the rough endoplasmic reticulum broke into fragments; and numerous lipid droplets formed in the cell. (C) 2001 Academic Press.