Male sexual enhancement after methoprene treatment in Anastrepha fraterculus (Diptera: Tephritidae): A sustained response that does not fade away after sexual maturation.

PubMed

Bachmann, G E; Devescovi, F; Nussenbaum, A L; Cladera, J L; Fernández, P C; Vera, M T; Teal, P E A; Segura, D F

2017-08-01

The juvenile hormone (JH) of insects triggers physiological changes related to reproduction in adults of both sexes. Methoprene is a sesquiterpene with some effects that are analogous to those of JH. Treatments with methoprene accelerate sexual maturation in males of the South American fruit fly Anastrepha fraterculus, giving young males a mating advantage over non-treated males of the same age. Here, we evaluated the effects of methoprene treatment on A. fraterculus males after the sexual maturation phase and tested whether this compound provides a long-term mating advantage. Moreover, we took the first step to unravel the mechanisms that underlie male sexual enhancement. We treated males 1day or 8days after adult emergence and compared mate choice between recently matured (young) females and females that had been mature for ca. 10days (aged females). We also addressed methoprene treatment effects on male sexual signalling. We found that methoprene treatment enhanced male sexual competitiveness even after the sexual maturation phase, and the effect did not decrease until males were older than 20days. However, when methoprene treatment was carried out close to sexual maturity, the mating enhancement was no longer observed, suggesting a non-immediate effect and excluding the possibility that methoprene acts as a pheromonal compound. Young and aged females tended to mate more frequently with treated-males. This might indicate that in a context of sexual selection, the potential benefits associated with reproductive success would be similar for females of both ages. Treated males released larger amounts of pheromonal compounds than non-treated males, but their courtship behaviour was not altered to the same extent, suggesting that methoprene treatment may accelerate differently the components of male courtship. We discuss potential benefits of using methoprene to increase the efficiency of the sterile insect technique, which is an environmentally safe method to

Sexuality and Young Children.

ERIC Educational Resources Information Center

Honig, Alice Sterling

2000-01-01

Describes normal aspects of sexuality during the early years, including masturbation and children's fanciful sexual ideas. Presents inappropriately mature sexual knowledge as a danger sign of abuse. Discusses whether and what teachers/caregivers should tell children about sexuality, and notes the importance of teaching staff about sexual identity…

Cardiovascular fitness in adolescents: the influence of sexual maturation status-the AVENA and EYHS studies.

PubMed

Ortega, Francisco B; Ruiz, Jonatan R; Mesa, Jose L; Gutiérrez, Angel; Sjöström, Michael

2007-01-01

The purposes were: (1) to determine the influence of sexual maturation status and body composition by comparing cardiovascular fitness (CVF) level in two adolescent populations from the south and the north of Europe; (2) to describe the associations between CVF and sexual maturation status in adolescence. A total of 1,867 Spanish adolescents from the AVENA study and 472 from the Swedish part of the EYHS were selected for this report (aged 14-16 years). CVF (expressed by the maximal oxygen consumption) was estimated from 20 m shuttle run test in the AVENA study and from a maximal ergometer cycle test in the EYHS. Sexual maturation status was classified according to Tanner stages. Body fat percentage (BF%) was estimated from skinfold thicknesses. Expressing CVF in different ways (in absolute value and in relation to weight or fat free mass; FFM) resulted in two different results with regard to CVF interpretation and comparison between the study populations. A higher CVF, as expressed in relation to FFM, was observed in the Spanish when compared to Swedish adolescents (P = 0.001). However, after adjusting for both sexual maturation status and BF%, the difference disappeared in males, while it remained significant in females (P = 0.001). CVF was negatively associated with sexual maturation status in males (P = 0.001). However, after adjusting for BF%, the association disappeared in males, while it was significant in females (P = 0.05). These results suggest that for CVF comparisons and interpretation in adolescent populations, sexual maturation status and BF%, as well as the way to express the CVF, should be taken into account. Copyright 2007 Wiley-Liss, Inc.

Does the sex ratio at sexual maturity affect men's later-life mortality risks? Evidence from historical China.

PubMed

Zang, Emma; Zheng, Hui

2018-04-01

This study examines the relationship between the male-to-female sex ratio (measured as the proportion male) at sexual maturity and later-life mortality risks in the context of pre-industrial northeast China, using registration data from the Qing Dynasty. We find that a higher male-to-female sex ratio at sexual maturity is associated with a higher later-life mortality risk among men. This association is likely due to the long-term adverse consequences of stress caused by low mate availability at sexual maturity. We further find that a high sex ratio at sexual maturity mitigates the health benefits of marriage and exacerbates the health disadvantages of holding an official position in Qing China. Copyright © 2018 Elsevier Ltd. All rights reserved.

Somatotype, physical growth, and sexual maturation in young male smokers.

PubMed Central

Lall, K B; Singhi, S; Gurnani, M; Singhi, P; Garg, O P

1980-01-01

One thousand school boys aged 8 to 16 were examined for their somatotype, physical growth, sexual maturation, and smoking habits. Fifty-two boys were found to be smokers, of whom 30 were regularly smoking between two and 20 bidis or cigarettes a day for a mean duration of 2.5 years. The mean height and weight of the smokers was significantly lower than that of the non-smokers at all ages, more so in regular than occasional smokers. Sixty-nine per cent of the smokers had mesomorphic type of body build; about 65% of the non-smokers had ectomorphic somatotype (P less than 0.001). Onset of puberty occurred significantly earlier among smokers compared with non-smokers, as was evident from the early appearance of genital stage 2, and an early and rapid increase in testicular size. Genital stage 2 appeared at a mean age of 11 years in smokers and 11.6 years in non-smokers. However, the appearance of pubic, axillary, and facial hair was delayed. The possible significance of this is discussed. PMID:7241030

Familial isolated growth-hormone deficiency with advanced sexual maturation.

PubMed

Kauschansky, A; Cohen, H A; Varsano, I; Laron, Z; Frydman, M

1993-02-01

Two brothers, aged 15 1/2 and 13 1/2 years, with dwarfism, microcephaly, and advanced sexual and skeletal maturation are described. One patient was mentally retarded. The parents were first cousins. Endocrine studies of these patients documented low growth-hormone levels after clonidine and insulin stimulation and blunted growth-hormone response to growth hormone releasing hormone. Gonadotropin releasing hormone stimulation produced no changes in levels of luteinizing and follicle-stimulating hormones. Basal levels of 17-alpha-hydroxyprogesterone were elevated in the two patients and increased further in response to stimulation with corticotropin. Levels of testosterone, dehydroepiandrosterone sulfate, and androstenedione were variably increased in both patients and showed a proportional increase on stimulation with human chorionic gonadotropin. To our knowledge, this is the first report of a familial association between growth-hormone deficiency and advanced bone and sexual maturation. A pituitary and an independent adrenal defect could account for the observations in these patients, but in view of the familial recurrence, a common underlying defect is possible.

Maturity Group Classification and Maturity Locus Genotyping of Early-Maturing Soybean Varieties from High-Latitude Cold Regions

PubMed Central

Lu, Wencheng; Hou, Wensheng; Sun, Shi; Yan, Hongrui; Han, Tianfu

2014-01-01

Background With the migration of human beings, advances of agricultural sciences, evolution of planting patterns and global warming, soybeans have expanded to both tropical and high-latitude cold regions (HCRs). Unlike other regions, HCRs have much more significant and diverse photoperiods and temperature conditions over seasons or across latitudes, and HCR soybeans released there show rich diversity in maturity traits. However, HCR soybeans have not been as well classified into maturity groups (MGs) as other places. Therefore, it is necessary to identify MGs in HCRs and to genotype the maturity loci. Methods Local varieties were collected from the northern part of Northeast China and the far-eastern region of Russia. Maturity group reference (MGR) soybeans of MGs MG000, MG00, and MG0 were used as references during field experiments. Both local varieties and MGR soybeans were planted for two years (2010-2011) in Heihe (N 50°15′, E 127°27′, H 168.5 m), China. The days to VE (emergence), R1 (beginning bloom) and R7 (beginning maturity) were recorded and statistically analyzed. Furthermore, some varieties were further genotyped at four molecularly-identified maturity loci E1, E2, E3 and E4. Results The HCR varieties were classified into MG0 or even more early-maturing. In Heihe, some varieties matured much earlier than MG000, which is the most early-maturing known MG, and clustered into a separate group. We designated the group as MG0000, following the convention of MGs. HCR soybeans had relatively stable days to beginning bloom from emergence. The HCR varieties diversified into genotypes of E1, E2, E3 and E4. These loci had different effects on maturity. Conclusion HCRs diversify early-maturing MGs of soybean. MG0000, a new MG that matures much earlier than known MGs, was developed. HCR soybean breeding should focus more on shortening post-flowering reproductive growth. E1, E2, E3, and E4 function differentially. PMID:24740097

Maturity group classification and maturity locus genotyping of early-maturing soybean varieties from high-latitude cold regions.

PubMed

Jia, Hongchang; Jiang, Bingjun; Wu, Cunxiang; Lu, Wencheng; Hou, Wensheng; Sun, Shi; Yan, Hongrui; Han, Tianfu

2014-01-01

With the migration of human beings, advances of agricultural sciences, evolution of planting patterns and global warming, soybeans have expanded to both tropical and high-latitude cold regions (HCRs). Unlike other regions, HCRs have much more significant and diverse photoperiods and temperature conditions over seasons or across latitudes, and HCR soybeans released there show rich diversity in maturity traits. However, HCR soybeans have not been as well classified into maturity groups (MGs) as other places. Therefore, it is necessary to identify MGs in HCRs and to genotype the maturity loci. Local varieties were collected from the northern part of Northeast China and the far-eastern region of Russia. Maturity group reference (MGR) soybeans of MGs MG000, MG00, and MG0 were used as references during field experiments. Both local varieties and MGR soybeans were planted for two years (2010-2011) in Heihe (N 50°15', E 127°27', H 168.5 m), China. The days to VE (emergence), R1 (beginning bloom) and R7 (beginning maturity) were recorded and statistically analyzed. Furthermore, some varieties were further genotyped at four molecularly-identified maturity loci E1, E2, E3 and E4. The HCR varieties were classified into MG0 or even more early-maturing. In Heihe, some varieties matured much earlier than MG000, which is the most early-maturing known MG, and clustered into a separate group. We designated the group as MG0000, following the convention of MGs. HCR soybeans had relatively stable days to beginning bloom from emergence. The HCR varieties diversified into genotypes of E1, E2, E3 and E4. These loci had different effects on maturity. HCRs diversify early-maturing MGs of soybean. MG0000, a new MG that matures much earlier than known MGs, was developed. HCR soybean breeding should focus more on shortening post-flowering reproductive growth. E1, E2, E3, and E4 function differentially.

The Development of Reproductive Strategy in Females: Early Maternal Harshness [right arrow] Earlier Menarche [right arrow] Increased Sexual Risk Taking

ERIC Educational Resources Information Center

Belsky, Jay; Steinberg, Laurence; Houts, Renate M.; Halpern-Felsher, Bonnie L.

2010-01-01

To test a proposition central to J. Belsky, L. Steinberg, and P. Draper's (1991) evolutionary theory of socialization--that pubertal maturation plays a role in linking early rearing experience with adolescent sexual risk taking (i.e., frequency of sexual behavior) and, perhaps, other risk taking (e.g., alcohol, drugs, delinquency)--the authors…

Sexual Risk Behavior in Young Adulthood: Broadening the Scope Beyond Early Sexual Initiation

PubMed Central

Epstein, Marina; Bailey, Jennifer A.; Manhart, Lisa E.; Hill, Karl G.; Hawkins, J. David

2013-01-01

A robust link between early sexual initiation and sexual risk-taking behavior is reported in previous studies. The relationship may not be causal, however, as the effect of common risk factors is often not considered. The current study examined whether early initiation is a key predictor of risky sexual behavior in the 20s and 30s, over and above co-occurring individual and environmental factors. Data were drawn from the Seattle Social Development Project, a longitudinal panel of 808 youth. Early predictors (ages 10–15) and sexual risk-taking (ages 21–24 and 30–33) were assessed prospectively. Early sexual initiation (before age 15) was entered into a series of probit regressions that also included family, neighborhood, peer, and individual risk factors. Although a positive bivariate relation between early sexual initiation and sexual risk-taking was observed at both ages, the link did not persist when co-occurring risk factors were included. Behavioral disinhibition and antisocial peer influences emerged as the strongest predictors of sexual risk over and above early sexual initiation. These results suggest that early sexual initiation must be considered in the context of common antecedents; public health policy aimed at delaying sexual intercourse alone is unlikely to substantially reduce sexual risk behavior in young adulthood. PMID:24423058

Alternative life histories in Xiphophorus multilineatus: evidence for different ages at sexual maturity and growth responses in the wild.

PubMed

Bono, L M; Rios-Cardenas, O; Morris, M R

2011-05-01

In order to examine potential trade-offs in alternative life histories of the high-backed pygmy swordtail Xiphophorus multilineatus, otoliths were used from wild-caught males to determine if sneaker males had the advantage of maturing earlier in natural environments. The sneakers matured significantly earlier than courters, but there was no difference among the three courter variants. In addition, analyses suggested that the effect of the pituitary locus on size at sexual maturity and growth rates was a consequence of age at sexual maturity. Finally, one of the courter variants had a significantly different relationship between age and size at sexual maturity than the other variants, suggesting that in this variant, age at sexual maturity may be more closely related to size and therefore may be less plastic in its growth responses. © 2011 The Authors. Journal of Fish Biology © 2011 The Fisheries Society of the British Isles.

Obesity induced during sexual maturation is linked to LDL-triacylglycerols in Yucatan miniature swine.

PubMed

Sébert, Sylvain P; Lecannu, Gérard; Sené, Sandrine; Hucteau, Séverine; Chetiveaux, Maud; Ouguerram, Khadija; Champ, Martine M-J

2005-08-01

The incidence of childhood obesity is rising dramatically throughout industrialised countries. To evaluate and study the impact of childhood obesity on lipoprotein metabolism, we developed a new animal model of premature obesity. Yucatan mini-pigs aged 4 months were studied over a 12-month period from childhood to adulthood. Animals were divided into two groups: the first group were overfed a Western misbalanced diet; the second group were normally fed a recommended human-type diet. Cholesterol and triacylglycerol concentrations in VLDL-, LDL- and HDL-lipoproteins were followed from baseline to adulthood by fast protein liquid chromatography. At 10 (the end of sexual maturation) and 16 months old (adulthood), liver, visceral and subcutaneous adipose tissues were sampled. Real-time RT-PCR was performed in order to compare apo AI, apo B, apo C-III, PPAR-alpha, insulin receptor and lipoprotein lipase gene expression between groups and ages. Differences between groups were observed only after sexual maturity. Adult overfed mini-pigs had a higher LDL-cholesterol:HDL-cholesterol ratio (P < 0.05; 0.55 (SE 0.06) for overfed v. 0.42 (SE 0.04) for normally fed pigs at the tenth month of the study). In both groups, VLDL-triacylglycerol decreased (P < 0.05). VLDL-triacylglycerol evolution in the overfed group was associated with an increase in LDL-triacylglycerol plasma concentrations (P < 0.05) after sexual maturation. LDL-triacylglycerol concentration in overfed mini-pigs went from an average of 0.28 mmol/l before sexual maturation to reach an average concentration of 0.56 mmol/l afterwards. This phenomenon has never been observed in similar studies when obesity is induced in adult mini-pigs and may represent a specific hallmark of an obesity induced during sexual maturity.

Individual heterogeneity in growth and age at sexual maturity: A gamma process analysis of capture–mark–recapture data

USGS Publications Warehouse

Link, William; Hesed, Kyle Miller

2015-01-01

Knowledge of organisms’ growth rates and ages at sexual maturity is important for conservation efforts and a wide variety of studies in ecology and evolutionary biology. However, these life history parameters may be difficult to obtain from natural populations: individuals encountered may be of unknown age, information on age at sexual maturity may be uncertain and interval-censored, and growth data may include both individual heterogeneity and measurement errors. We analyzed mark–recapture data for Red-backed Salamanders (Plethodon cinereus) to compare sex-specific growth rates and ages at sexual maturity. Aging of individuals was made possible by the use of a von Bertalanffy model of growth, complemented with models for interval-censored and imperfect observations at sexual maturation. Individual heterogeneity in growth was modeled through the use of Gamma processes. Our analysis indicates that female P. cinereus mature earlier and grow more quickly than males, growing to nearly identical asymptotic size distributions as males.

Early sexual maturity in local boars of Northeastern India: age-related changes in testicular growth, epididymal sperm characteristics and peripheral testosterone levels.

PubMed

Kumaresan, A; Bujarbaruah, K M; Kadirvel, G; Khargharia, G; Sarma, Rumi G; Goswami, J; Basumatary, Rantu; Palaniappan, Kavitha; Bardoloi, R K

2011-03-01

The present study reports the age related changes in the peripheral testosterone levels, testicular and epididymal growth and development and cauda epididymal spermiogram in local pigs of Northeastern India, which attain sexual maturity around 3 months of age. Local boars (n = 20) were castrated at monthly intervals from 2 to 6 months of age (4 boars per month) to study the testicular growth and development and the epididymal spermiogram. Blood samples, collected from local boars (n = 6) at monthly intervals from 2 to 6 months of age, were analyzed for testosterone levels by radioimmunoassay. Compared to Hampshire boars, significantly (P < 0.05) high testosterone levels were observed in the local boars as early as 2 months of age. The mean (± SEM) level of testosterone in the local boars at 2, 3 and 4 months of age was 11.89 ± 1.52, 20.45 ± 1.33 and 20.38 ± 2.0 ngml(-1), respectively. Though there was consistently significant (P < 0.05) difference in the body weight between Hampshire and local pigs, the same was not observed in case of testicular weight except at 3 and 6 months of age. In line with the above observation, the testis:body weight ratio (gram testis per kg body weight) was significantly (P < 0.05) higher in the local boars compared to the Hampshire boars at any time of observation, which ranged from 0.8 to 1.0 in case of Hampshire and from 2.3 to 3.0 in local boars. The sperm concentration in the cauda epididymal fluid of local boars at 2, 3 and 6 months of age was 2255 ± 186.6, 3685 ± 103.8 and 4325 ± 146.2 million/ml, respectively and the sperm motility, viability and total abnormality was 73.3, 75.2 and 6.2%, respectively at 3 months of age. Taken together, the testosterone level, testicular growth and development and epididymal spermiogram indicate the trait of early sexual maturity in the local pigs as compared to Hampshire. Copyright © 2011 Elsevier Inc. All rights reserved.

The Developmental Pathway From Pubertal Timing to Delinquency and Sexual Activity From Early to Late Adolescence

PubMed Central

Negriff, Sonya; Elizabeth, J. Susman; Trickett, Penelope K.

2013-01-01

There is strong evidence that early pubertal timing is associated with adolescent problem behaviors. However, there has been limited investigation of the mechanisms or developmental relationships. The present study examined longitudinal models incorporating pubertal timing, delinquency, and sexual activity in a sample of 454 adolescents (9–13 years old at enrollment; 47% females). Participants were seen for three assessments approximately 1 year apart. Characteristics of friendship networks (older friends, male friends, older male friends) were examined as mediators. Structural equation modeling was used to test these associations as well as temporal relationships between sexual activity and delinquency. Results showed that early pubertal timing at Time 1 was related to more sexual activity at Time 2, which was related to higher delinquency at Time 3, a trend mediation effect. None of the friendship variables mediated these associations. Gender or maltreatment status did not moderate the meditational pathways. The results also supported the temporal sequence of sexual activity preceding increases in delinquency. These findings reveal that early maturing adolescents may actively seek out opportunities to engage in sexual activity which appears to be risk for subsequent delinquency. PMID:21191640

The developmental pathway from pubertal timing to delinquency and sexual activity from early to late adolescence.

PubMed

Negriff, Sonya; Susman, Elizabeth J; Trickett, Penelope K

2011-10-01

There is strong evidence that early pubertal timing is associated with adolescent problem behaviors. However, there has been limited investigation of the mechanisms or developmental relationships. The present study examined longitudinal models incorporating pubertal timing, delinquency, and sexual activity in a sample of 454 adolescents (9-13 years old at enrollment; 47% females). Participants were seen for three assessments approximately 1 year apart. Characteristics of friendship networks (older friends, male friends, older male friends) were examined as mediators. Structural equation modeling was used to test these associations as well as temporal relationships between sexual activity and delinquency. Results showed that early pubertal timing at Time 1 was related to more sexual activity at Time 2, which was related to higher delinquency at Time 3, a trend mediation effect. None of the friendship variables mediated these associations. Gender or maltreatment status did not moderate the meditational pathways. The results also supported the temporal sequence of sexual activity preceding increases in delinquency. These findings reveal that early maturing adolescents may actively seek out opportunities to engage in sexual activity which appears to be risk for subsequent delinquency.

Reproductive strategy, sexual development and attraction to facial characteristics

PubMed Central

Cornwell, R. Elisabeth; Law Smith, Miriam J; Boothroyd, Lynda G; Moore, Fhionna R; Davis, Hasker P; Stirrat, Michael; Tiddeman, Bernard; Perrett, David I

2006-01-01

Sexual reproduction strategies vary both between and within species in the level of investment in offspring. Life-history theories suggest that the rate of sexual maturation is critically linked to reproductive strategy, with high investment being associated with few offspring and delayed maturation. For humans, age of puberty and age of first sex are two developmental milestones that have been associated with reproductive strategies. Stress during early development can retard or accelerate sexual maturation and reproduction. Early age of menarche is associated with absence of younger siblings, absence of a father figure during early life and increased weight. Father absence during early life is also associated with early marriage, pregnancy and divorce. Choice of partner characteristics is critical to successful implementation of sexual strategies. It has been suggested that sexually dimorphic traits (including those evident in the face) signal high-quality immune function and reproductive status. Masculinity in males has also been associated with low investment in mate and offspring. Thus, women's reproductive strategy should be matched to the probability of male investment, hence to male masculinity. Our review leads us to predict associations between the rate of sexual maturation and adult preferences for facial characteristics (enhanced sexual dimorphism and attractiveness). We find for men, engaging in sex at an early age is related to an increased preference for feminized female faces. Similarly, for women, the earlier the age of first sex the greater the preference for masculinity in opposite-sex faces. When we controlled sexual dimorphism in male faces, the speed of sexual development in women was not associated with differences in preference for male facial attractiveness. These developmental influences on partner choice were not mediated by self-rated attractiveness or parental relationships. We conclude that individuals assort in preferences based on

Reproductive strategy, sexual development and attraction to facial characteristics.

PubMed

Cornwell, R Elisabeth; Law Smith, Miriam J; Boothroyd, Lynda G; Moore, Fhionna R; Davis, Hasker P; Stirrat, Michael; Tiddeman, Bernard; Perrett, David I

2006-12-29

Sexual reproduction strategies vary both between and within species in the level of investment in offspring. Life-history theories suggest that the rate of sexual maturation is critically linked to reproductive strategy, with high investment being associated with few offspring and delayed maturation. For humans, age of puberty and age of first sex are two developmental milestones that have been associated with reproductive strategies. Stress during early development can retard or accelerate sexual maturation and reproduction. Early age of menarche is associated with absence of younger siblings, absence of a father figure during early life and increased weight. Father absence during early life is also associated with early marriage, pregnancy and divorce. Choice of partner characteristics is critical to successful implementation of sexual strategies. It has been suggested that sexually dimorphic traits (including those evident in the face) signal high-quality immune function and reproductive status. Masculinity in males has also been associated with low investment in mate and offspring. Thus, women's reproductive strategy should be matched to the probability of male investment, hence to male masculinity. Our review leads us to predict associations between the rate of sexual maturation and adult preferences for facial characteristics (enhanced sexual dimorphism and attractiveness). We find for men, engaging in sex at an early age is related to an increased preference for feminized female faces. Similarly, for women, the earlier the age of first sex the greater the preference for masculinity in opposite-sex faces. When we controlled sexual dimorphism in male faces, the speed of sexual development in women was not associated with differences in preference for male facial attractiveness. These developmental influences on partner choice were not mediated by self-rated attractiveness or parental relationships. We conclude that individuals assort in preferences based on

Sex steroids in relation to sexual and skeletal maturation in obese male adolescents.

PubMed

Vandewalle, S; Taes, Y; Fiers, T; Van Helvoirt, M; Debode, P; Herregods, N; Ernst, C; Van Caenegem, E; Roggen, I; Verhelle, F; De Schepper, J; Kaufman, J M

2014-08-01

Childhood obesity is associated with an accelerated skeletal maturation. However, data concerning pubertal development and sex steroid levels in obese adolescents are scarce and contrasting. To study sex steroids in relation to sexual and skeletal maturation and to serum prostate specific antigen (PSA), as a marker of androgen activity, in obese boys from early to late adolescence. Ninety obese boys (aged 10-19 y) at the start of a residential obesity treatment program and 90 age-matched controls were studied cross-sectionally. Pubertal status was assessed according to the Tanner method. Skeletal age was determined by an x-ray of the left hand. Morning concentrations of total testosterone (TT) and estradiol (E2) were measured by liquid chromatography-tandem mass spectrometry, free T (FT) was measured by equilibrium dialysis, and LH, FSH, SHBG, and PSA were measured by immunoassays. Genital staging was comparable between the obese and nonobese groups, whereas skeletal bone advancement (mean, 1 y) was present in early and midadolescence in the obese males. Although both median SHBG and TT concentrations were significantly (P < .001) lower in obese subjects during mid and late puberty, median FT, LH, FSH, and PSA levels were comparable to those of controls. In contrast, serum E2 concentrations were significantly (P < .001) higher in the obese group at all pubertal stages. Obese boys have lower circulating SHBG and TT, but similar FT concentrations during mid and late puberty in parallel with a normal pubertal progression and serum PSA levels. Our data indicate that in obese boys, serum FT concentration is a better marker of androgen activity than TT. On the other hand, skeletal maturation and E2 were increased from the beginning of puberty, suggesting a significant contribution of hyperestrogenemia in the advancement of skeletal maturation in obese boys.

Elevated Social Anxiety among Early Maturing Girls

PubMed Central

Blumenthal, Heidemarie; Leen-Feldner, Ellen W.; Babson, Kimberly A.; Gahr, Jessica L.; Trainor, Casey D.; Frala, Jamie L.

2012-01-01

Adolescence is a key period in terms of the development of anxiety psychopathology. An emerging literature suggests that early pubertal maturation is associated with enhanced vulnerability for anxiety symptomatology, although few studies have examined this association with regard to social anxiety. Accordingly, the current study was designed to further elucidate the relation between pubertal timing and social anxiety, with a focus on clarifying the role of gender. Participants were 138 adolescents (ages 12-17 years) recruited from the general community. Level of social anxiety was examined as a function of gender and within-sample pubertal timing. As expected, early-maturing girls evidenced significantly higher social anxiety as compared to on-time girls and early-maturing boys, and no other differences were found as a function of gender or developmental timing. Findings and future directions are discussed in terms of forwarding developmentally-sensitive models of social anxiety etiology and prevention. PMID:21604866

Early menarche: A systematic review of its effect on sexual and reproductive health in low- and middle-income countries.

PubMed

Ibitoye, Mobolaji; Choi, Cecilia; Tai, Hina; Lee, Grace; Sommer, Marni

2017-01-01

Adolescent girls aged 15-19 bear a disproportionate burden of negative sexual and reproductive health outcomes in low- and middle-income countries. Research from several high-income countries suggests that early age at menarche is an important determinant of sexual and reproductive health. We conducted this systematic review to better understand whether and how early menarche is associated with various negative sexual and reproductive health outcomes in low- and middle-income countries and the implications of such associations. We systematically searched eight health and social sciences databases for peer-reviewed literature on menarche and sexual and reproductive health in low- and middle-income countries. Two reviewers independently assessed all studies for inclusion, overall quality and risk of bias, and performed data extraction on all included studies. Twenty-four articles met all inclusion criteria-nine of moderate quality and fifteen with several methodological weaknesses. Our review of the minimal existing literature showed that early menarche is associated with early sexual initiation, early pregnancy and some sexually transmitted infections in low- and middle-income countries, similar to what has been observed in high-income countries. Early menarche is also associated with early marriage-an association that may have particularly important implications for countries with high child marriage rates. Early age at menarche may be an important factor affecting the sexual and reproductive health of adolescent girls and young women in low- and middle-income countries. More research is needed to confirm the existence of the identified associations across different settings and to better understand the process through which early menarche and other markers of early pubertal development may contribute to the increased vulnerability of girls to negative sexual and reproductive health outcomes in low- and middle-income countries. Given the association of early

Neurokinin B is critical for normal timing of sexual maturation but dispensable for adult reproductive function in female mice.

PubMed

True, Cadence; Nasrin Alam, Sayeda; Cox, Kimberly; Chan, Yee-Ming; Seminara, Stephanie B

2015-04-01

Humans carrying mutations in neurokinin B (NKB) or the NKB receptor fail to undergo puberty due to decreased secretion of GnRH. Despite this pubertal delay, many of these patients go on to achieve activation of their hypothalamic-pituitary-gonadal axis in adulthood, a phenomenon termed reversal, indicating that NKB signaling may play a more critical role for the timing of pubertal development than adult reproductive function. NKB receptor-deficient mice are hypogonadotropic but have no defects in the timing of sexual maturation. The current study has performed the first phenotypic evaluation of mice bearing mutations in Tac2, the gene encoding the NKB ligand, to determine whether they have impaired sexual development similar to their human counterparts. Male Tac2-/- mice showed no difference in the timing of sexual maturation or fertility compared with wild-type littermates and were fertile. In contrast, Tac2-/- females had profound delays in sexual maturation, with time to vaginal opening and first estrus occurring significantly later than controls, and initial abnormalities in estrous cycles. However, cycling recovered in adulthood and Tac2-/- females were fertile, although they produced fewer pups per litter. Thus, female Tac2-/- mice parallel humans harboring NKB pathway mutations, with delayed sexual maturation and activation of the reproductive cascade later in life. Moreover, direct comparison of NKB ligand and receptor-deficient females confirmed that only NKB ligand-deficient animals have delayed sexual maturation, suggesting that in the absence of the NKB receptor, NKB may regulate the timing of sexual maturation through other tachykinin receptors.

Mother-daughter communication about sexual maturation, abstinence and unintended pregnancy: experiences from an informal settlement in Nairobi, Kenya.

PubMed

Crichton, Joanna; Ibisomi, Latifat; Gyimah, Stephen Obeng

2012-02-01

Parental communication and support is associated with improved developmental, health and behavioral outcomes in adolescence. This study explores the quality of mother-daughter communication about sexual maturation, abstinence and unintended pregnancy in Korogocho, an informal settlement in Nairobi, Kenya. We use data from 14 focus group discussions (n = 124) and 25 interviews with girls aged 12-17, mothers of teenage girls, and key informant teachers. Many girls and women believed that mothers are the best source of information and support during puberty but only a minority described good experiences with communication in practice. Girls preferred communication to begin early and be repeated regularly. Mothers often combined themes of sexual maturation, abstinence and avoiding pregnancy in their messages. Communication was facilitated by mothers' availability, warmth and close parent-child relationships. Challenges included communication taboos, embarrassment, ambiguous message content, and parental lack of knowledge and uncertainty. Neighborhood poverty undermined some mothers' time and motivation for communicating. Copyright © 2011 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

[Pubertal maturation, physical self-esteem and sexuality in a sample of French adolescents].

PubMed

Potard, C; Courtois, R; Clarisse, R; Le Floc'h, N; Thomine, M; Réveillère, C

2016-04-01

The aim of this study was to explore the links between pubertal maturation, physical self-esteem and sexuality in adolescence, differentiating between boys and girls. The sample was comprised of 312 French secondary school children (seventh and ninth grades); 52.6 % (n=164) of whom were girls. Participants answered three self-evaluation questionnaires: the scale of sexuality (interests, emotions, relationships: IERS) in prime adolescence (12 to 15 years); (b) the self-administered rating scale for pubertal development and (c) the Physical Self-Description Questionnaire (PSDQ). Pubertal maturation was associated with higher scores on "Flirting with the aim of having sexual relations" and "Going out with someone", and a drop in overall and physical self-esteem, mainly in socially valued domains, namely "Body fat" for girls, and "Strength" and "Health" for boys. Overall physical self-esteem was associated with "Going out with someone" and "Flirting with the aim of having sexual relations" in boys. Physical changes at puberty induce two distinct trends in adolescents: sexual exploration and discovery (genitalized body), and self-depreciation (social body). Copyright © 2015 L’Encéphale, Paris. Published by Elsevier Masson SAS. All rights reserved.

Timing of pubertal maturation and the onset of sexual behavior among Zimbabwe school boys.

PubMed

Campbell, Benjamin C; Prossinger, Hermann; Mbzivo, Michael

2005-10-01

The relationship between reproductive maturation and the onset of sexual behavior in boys across cultures is unclear. To explore the relative timing of pubertal events and their relationship to the onset of sexual behavior, we used data collected from 442 Zimbabwe school boys aged 12-18 years. Measures of reproductive maturation included self-reported spontaneous nocturnal emission, secondary sexual characteristics, and salivary testosterone. Behavioral measures included age at first sexual fantasies, non-coital sexual behavior, and coitus. Sigmoid interpolation curve techniques indicated a median age of first erection at 10.75 +/- 0.11 years, first sexual fantasy at 12.66 +/- 0.03 years, first spontaneous nocturnal emission at 13.02 +/- 0.03 years, and adult levels of blood testosterone at 17.2 +/- 0.7 years. First reported spontaneous nocturnal emission was significantly related to all measures of sexual behavior. Multiple regression models indicated that first reported spontaneous nocturnal emission was a stronger predictor of sexual behavior than variation in secondary sexual characteristics. In addition, testosterone was a significant predictor of sexual fantasies and intercourse, independent of first reported spontaneous nocturnal emission. These results confirm earlier findings in other populations that self-reported spontaneous nocturnal emissions can be used as a marker of pubertal timing among adolescent boys. They also suggest that variation in testosterone plays a role in the onset of sexual behavior among boys, beyond its relationship to developmental timing. The behavioral mechanisms represented by the significant effects of testosterone reported here remain to be investigated.

Effects of sexual maturation and Salmonella infection on the expression of Toll-like receptors in the chicken vagina.

PubMed

Michailidis, G; Theodoridis, A; Avdi, M

2011-02-01

Toll-like receptors (TLRs) are a critical component of the innate immune response in many vertebrates, including avian species. The recent findings of chicken TLRs (cTLRs) expression in ovarian follicles and in the chicken ovary in vivo, as well as the changes in their expression in response to lipopolysaccharide or Salmonella enteritidis (SE) infection, have broad implications for reproductive physiology and for the prevention of transmission of zoonotic diseases to humans through the consumption of contaminated poultry eggs. Because the main route of egg contamination is from infection of the oviduct and mainly from the vagina, the aim of this study was to investigate the expression of the ten cTLRs identified to date in the chicken oviduct in vivo, to determine whether sexual maturation affects their mRNA abundance and to investigate whether SE infection alters the expression of TLRs in the chicken vagina. RNA was extracted from the vagina of healthy prepubertal, sexually mature and aged birds, and from sexually mature and aged SE infected birds. RT-PCR analysis revealed that all types of cTLRs apart from TLR1-1 were expressed in the vagina of sexually mature birds. Quantitative real-time PCR analysis revealed that the mRNA abundance of TLR2-1, 2-2 and 4 differ with respect to sexual maturation in the chicken vagina. SE infection resulted in a significant induction of TLR5 and 15 in the vagina of sexually mature birds, and in a significant induction of TLR2-1, 4 and 15 in the vagina of aged birds, while a significant down-regulation was observed for TLR7 in the vagina of sexually mature birds. These findings suggest that a TLR mediated immune response mechanism exists in the chicken vagina, playing a crucial role in preventing microbial pathogens from being incorporated into newly forming eggs. Copyright © 2011 Elsevier B.V. All rights reserved.

Emergence, development, and maturity of the gonad of two species of chitons "sea cockroach" (Mollusca: Polyplacophora) through the early life stages.

PubMed

Avila-Poveda, Omar Hernando; Abadia-Chanona, Quetzalli Yasú

2013-01-01

This study describes and recognises, using histological and microscopical examinations on a morphometrical basis, several gonad traits through the early life stages of Chiton articulatus and C. albolineatus. Gonadal ontogenesis, gonad development stages, sexual differentiation, onset of the first sexual maturity, and growth sequences or "early life stages" were determined. In addition, allometry between lengths and body weight pooled for both sexes per each chiton were calculated using equation Y = aX(b) . A total of 125 chitons (4≤TL≤40 mm, in total length "TL") were used. All allometric relations showed a strong positive correlation (r), close to 1, with b-values above three, indicating an isometric growth. Gonadal ontogenesis and gonad development stages were categorised into three periods ("Pw" without gonad, "Pe" gonad emergence, and "Pf" gonadal sac formed) and four stages ("S0" gametocytogenesis, "S1" gametogenesis, "S2" mature, and "S3" spawning), respectively. Compound digital images were attained for each process. Periods and stages are overlapped among them and between species, with the following overall confidence intervals in TL: Pw 6.13-14.32 mm, Pe 10.32-16.93 mm, Pf 12.99-25.01 mm, S0 16.08-24.34 mm (females) and 19.51-26.60 mm (males), S1 27.15-35.63 mm (females) and 23.45-32.27 mm (males), S2 24.48-40.24 mm (females) and 25.45-32.87 mm (males). Sexual differentiation (in S0) of both chitons occurs first as a female then as a male; although, males reach the onset of the first sexual maturity earlier than females, thus for C. articulatus males at 17 mm and females at 32 mm, and for C. albolineatus males at 23.5 mm and females at 28 mm, all in TL. Four early life stages (i.e., subjuvenile, juvenile, subadult, and adult) are described and proposed to distinguish growth sequences. Our results may be useful to diverse disciplines, from developmental biology to fisheries management.

Depressive Symptomatology among Very Early Maturing Girls.

ERIC Educational Resources Information Center

Rierdan, Jill; Koff, Elissa

1991-01-01

The relationship between very early menarche and depression was studied in a sample of 488 girls (336 sixth graders and 152 seventh graders), less than 10 percent of whom were very early maturers. Very early menarche was associated with higher levels of depression than was more normative development. (SLD)

Prepubertal Serum Concentrations of Organochlorine Pesticides and Age at Sexual Maturity in Russian Boys.

PubMed

Lam, Thuy; Williams, Paige L; Lee, Mary M; Korrick, Susan A; Birnbaum, Linda S; Burns, Jane S; Sergeyev, Oleg; Revich, Boris; Altshul, Larisa M; Patterson, Donald G; Hauser, Russ

2015-11-01

Few human studies have evaluated the impact of childhood exposure to organochlorine pesticides (OCP) on pubertal development. We evaluated associations of serum OCP concentrations [hexachlorobenzene (HCB), β-hexachlorocyclohexane (βHCH), and p,p-dichlorodiphenyldichloroethylene (p,p´-DDE)] with age at attainment of sexual maturity among boys. From 2003 through 2005, 350 8- to 9-year-old boys from Chapaevsk, Russia, with measured OCPs were enrolled and followed annually for 8 years. We used multivariable interval-censored models to evaluate associations of OCPs (quartiles) with three physician-assessed measures of sexual maturity: Tanner stage 5 for genitalia growth, Tanner stage 5 for pubic hair growth, or testicular volume (TV) ≥ 20 mL in either testis. In adjusted models, boys with higher HCB concentrations achieved sexual maturity reflected by TV ≥ 20 mL a mean of 3.1 months (95% CI: -1.7, 7.8), 5.3 months (95% CI: 0.6, 10.1), and 5.0 months (95% CI: 0.2, 9.8) later for quartiles Q2, Q3, and Q4, respectively, compared with Q1 (p trend = 0.04). Tanner stage 5 for genitalia growth was attained a mean of 2.2 months (95% CI: -3.1, 7.5), 5.7 months (95% CI: 0.4, 11.0), and 3.7 months (95% CI: -1.7, 9.1) later for quartiles Q2, Q3, and Q4, respectively, of βHCH compared with Q1 (p trend = 0.09). Tanner stage 5 for pubic hair growth occurred 6-9 months later on average for boys in the highest versus lowest quartile for HCB (p trend < 0.001), βHCH (trend p = 0.01), and p,p´-DDE (p trend = 0.04). No associations were observed between p,p´-DDE and Tanner stage 5 for genitalia growth or TV ≥ 20 mL. Higher prepubertal serum HCB and βHCH concentrations were associated with a later age at attainment of sexual maturity. Only the highest quartile of serum p,p´-DDE was associated with later pubic hair maturation. Lam T, Williams PL, Lee MM, Korrick SA, Birnbaum LS, Burns JS, Sergeyev O, Revich B, Altshul LM, Patterson DG Jr, Hauser R. 2015. Prepubertal serum

BLOOD LEAD LEVELS AND SEXUAL MATURATION IN U.S. GIRLS: THE THIRD NATIONAL HEALTH AND NUTRITION EXAMINATION SURVEY, 1988-94

EPA Science Inventory

Context. Animal studies suggest that lead exposure may delay sexual maturation, raising concern about children's environmental lead exposure.
Objective. Assess the realtion between blood lead and sexual maturation in girls.
Design. Third National and Nutrition Examinatio...

Tropical anurans mature early and die young: Evidence from eight Afromontane Hyperolius species and a meta-analysis

PubMed Central

2017-01-01

Age- and size-related life-history traits of anuran amphibians are thought to vary systematically with latitude and altitude. Because the available data base is strongly biased towards temperate-zone species, we provide new estimates on eight afrotropical Reed Frog species. A meta-analysis of the demographic traits in 44 tropical anuran species aims to test for the predicted clinal variation and to contrast results with variation detected in temperate-zone species. The small-sized reed frogs reach sexual maturity during the first or second year of life, but longevity does not exceed three to four years. Latitudinal effects on demographic life-history traits are not detectable in tropical anurans, and altitudinal effects are limited to a slight size reduction at higher elevations. Common features of anuran life-history in the tropics are early sexual maturation at small size and low longevity resulting in low lifetime fecundity. This pattern contrasts with that found in temperate-zone anurans which mature later at larger size and grow considerably older yielding greater lifetime fecundity than in the tropics. Latitudinal and altitudinal contraction of the yearly activity period shape the evolution of life-history traits in the temperate region, while trait variation in the tropics seems to be driven by distinct, not yet identified selective forces. PMID:28182738

The Olfactory Transcriptome and Progression of Sexual Maturation in Homing Chum Salmon Oncorhynchus keta.

PubMed

Palstra, Arjan P; Fukaya, Kosuke; Chiba, Hiroaki; Dirks, Ron P; Planas, Josep V; Ueda, Hiroshi

2015-01-01

Reproductive homing migration of salmonids requires accurate interaction between the reception of external olfactory cues for navigation to the spawning grounds and the regulation of sexual maturation processes. This study aimed at providing insights into the hypothesized functional link between olfactory sensing of the spawning ground and final sexual maturation. We have therefore assessed the presence and expression levels of olfactory genes by RNA sequencing (RNAseq) of the olfactory rosettes in homing chum salmon Oncorhynchus keta Walbaum from the coastal sea to 75 km upstream the rivers at the pre-spawning ground. The progression of sexual maturation along the brain-pituitary-gonadal axis was assessed through determination of plasma steroid levels by time-resolved fluoroimmunoassays (TR-FIA), pituitary gonadotropin subunit expression and salmon gonadotropin-releasing hormone (sgnrh) expression in the brain by quantitative real-time PCR. RNAseq revealed the expression of 75 known and 27 unknown salmonid olfactory genes of which 13 genes were differentially expressed between fish from the pre-spawning area and from the coastal area, suggesting an important role of these genes in homing. A clear progression towards final maturation was characterised by higher plasma 17α,20β-dihydroxy-4-pregnen-3-one (DHP) levels, increased pituitary luteinizing hormone β subunit (lhβ) expression and sgnrh expression in the post brain, and lower plasma testosterone (T) and 17β-estradiol (E2) levels. Olfactomedins and ependymin are candidates among the differentially expressed genes that may connect olfactory reception to the expression of sgnrh to regulate final maturation.

The Olfactory Transcriptome and Progression of Sexual Maturation in Homing Chum Salmon Oncorhynchus keta

PubMed Central

Palstra, Arjan P.; Fukaya, Kosuke; Chiba, Hiroaki; Dirks, Ron P.; Planas, Josep V.; Ueda, Hiroshi

2015-01-01

Reproductive homing migration of salmonids requires accurate interaction between the reception of external olfactory cues for navigation to the spawning grounds and the regulation of sexual maturation processes. This study aimed at providing insights into the hypothesized functional link between olfactory sensing of the spawning ground and final sexual maturation. We have therefore assessed the presence and expression levels of olfactory genes by RNA sequencing (RNAseq) of the olfactory rosettes in homing chum salmon Oncorhynchus keta Walbaum from the coastal sea to 75 km upstream the rivers at the pre-spawning ground. The progression of sexual maturation along the brain-pituitary-gonadal axis was assessed through determination of plasma steroid levels by time-resolved fluoroimmunoassays (TR-FIA), pituitary gonadotropin subunit expression and salmon gonadotropin-releasing hormone (sgnrh) expression in the brain by quantitative real-time PCR. RNAseq revealed the expression of 75 known and 27 unknown salmonid olfactory genes of which 13 genes were differentially expressed between fish from the pre-spawning area and from the coastal area, suggesting an important role of these genes in homing. A clear progression towards final maturation was characterised by higher plasma 17α,20β-dihydroxy-4-pregnen-3-one (DHP) levels, increased pituitary luteinizing hormone β subunit (lhβ) expression and sgnrh expression in the post brain, and lower plasma testosterone (T) and 17β-estradiol (E2) levels. Olfactomedins and ependymin are candidates among the differentially expressed genes that may connect olfactory reception to the expression of sgnrh to regulate final maturation. PMID:26397372

Early menarche: A systematic review of its effect on sexual and reproductive health in low- and middle-income countries

PubMed Central

Choi, Cecilia; Tai, Hina; Lee, Grace; Sommer, Marni

2017-01-01

Background Adolescent girls aged 15–19 bear a disproportionate burden of negative sexual and reproductive health outcomes in low- and middle-income countries. Research from several high-income countries suggests that early age at menarche is an important determinant of sexual and reproductive health. We conducted this systematic review to better understand whether and how early menarche is associated with various negative sexual and reproductive health outcomes in low- and middle-income countries and the implications of such associations. Methods We systematically searched eight health and social sciences databases for peer-reviewed literature on menarche and sexual and reproductive health in low- and middle-income countries. Two reviewers independently assessed all studies for inclusion, overall quality and risk of bias, and performed data extraction on all included studies. Results Twenty-four articles met all inclusion criteria–nine of moderate quality and fifteen with several methodological weaknesses. Our review of the minimal existing literature showed that early menarche is associated with early sexual initiation, early pregnancy and some sexually transmitted infections in low- and middle-income countries, similar to what has been observed in high-income countries. Early menarche is also associated with early marriage–an association that may have particularly important implications for countries with high child marriage rates. Conclusions Early age at menarche may be an important factor affecting the sexual and reproductive health of adolescent girls and young women in low- and middle-income countries. More research is needed to confirm the existence of the identified associations across different settings and to better understand the process through which early menarche and other markers of early pubertal development may contribute to the increased vulnerability of girls to negative sexual and reproductive health outcomes in low- and middle

The Amelioration of Olfactory Acuity upon Sexual Maturation Might Affect Food Preferences

PubMed Central

Bignetti, Enrico; Sinesio, Fiorella; Aiello, Gaetano L.; Cannella, Carlo

2009-01-01

Upon sexual maturation, olfactory acuity in women ameliorates and starts oscillating across the cycle. During ovulation, mean olfactory threshold is 30 times lower than during bleeding. Interestingly, menstruated women undergo maleodorant trimethylaminuria. We argued that olfactory amelioration during ovulation might concur to a mating strategy, whereas olfactory impairment during bleeding might protect women against self-refusal. Testosterone and its 17β-estradiol derivative might be responsible for the synchronization of these menstrual events. Furthermore, we posed the question whether olfactory detection amelioration upon sexual maturation might provoke a change in food preferences, for instance a reduction in fish consumption. A preliminary survey in Italy provided encouraging results: 15-44 year-old women have lower fish consumption than 3-14 year-old girls. Surprisingly, men exhibited the same behaviour, so new olfactory tests as well as testosterone measurements are under way. PMID:22253964

Evaluation of genetic variability among "Early Mature" Juglans regia using microsatellite markers and morphological traits.

PubMed

Ebrahimi, Aziz; Zarei, Abdolkarim; Zamani Fardadonbeh, Mojtaba; Lawson, Shaneka

2017-01-01

Limiting the juvenile phase and reducing tree size are the two main challenges for breeders to improve most fruit crops. Early maturation and dwarf cultivars have been reported for many fruit species. "Early mature" and low vigor walnut genotypes were found among seedlings of Persian walnut. Nine microsatellite markers were used to evaluate genetic diversity among "Early Mature" Persian walnut accessions and provide a comparison with "normal growth" accessions. Six maturation related characteristics were also measured in "Early Mature" samples. Phenotypic traits and diversity indices showed relatively high levels of genetic diversity in "Early Mature" seedlings and indicated high differentiation between individuals. Seedling height, the most diverse phenotypic trait, has an important role in the clustering of "Early Mature" accessions. The "Early Mature" type had higher number of alleles, number of effective allele, and Shannon index compared to the "Normal Growth" group. The two types of studied walnuts had different alleles, with more than half of produced alleles specific to a specific group. "Early Mature" and "Normal Growth" walnuts had 27 and 17 private alleles, respectively. Grouping with different methods separated "Early Mature" and "Normal Growth" samples entirely. The presence of moderate to high genetic diversity in "Early Mature" walnuts and high genetic differentiation with "Normal Growth" walnuts, indicated that "Early Mature" walnuts were more diverse and distinct from "Normal Growth" samples. Moreover, our results showed SSR markers were useful for differentiating between "Early Mature" and "Normal Growth" walnuts. A number of identified loci have potential in breeding programs for identification of "Early Mature" walnuts at the germination phase.

The Role of Breast Size and Areolar Pigmentation in Perceptions of Women's Sexual Attractiveness, Reproductive Health, Sexual Maturity, Maternal Nurturing Abilities, and Age.

PubMed

Dixson, Barnaby J; Duncan, Melanie; Dixson, Alan F

2015-08-01

Women's breast morphology is thought to have evolved via sexual selection as a signal of maturity, health, and fecundity. While research demonstrates that breast morphology is important in men's judgments of women's attractiveness, it remains to be determined how perceptions might differ when considering a larger suite of mate relevant attributes. Here, we tested how variation in breast size and areolar pigmentation affected perceptions of women's sexual attractiveness, reproductive health, sexual maturity, maternal nurturing abilities, and age. Participants (100 men; 100 women) rated images of female torsos modeled to vary in breast size (very small, small, medium, and large) and areolar pigmentation (light, medium, and dark) for each of the five attributes listed above. Sexual attractiveness ratings increased linearly with breast size, but large breasts were not judged to be significantly more attractive than medium-sized breasts. Small and medium-sized breasts were rated as most attractive if they included light or medium colored areolae, whereas large breasts were more attractive if they had medium or dark areolae. Ratings for perceived age, sexual maturity, and nurturing ability also increased with breast size. Darkening the areolae reduced ratings of the reproductive health of medium and small breasts, whereas it increased ratings for large breasts. There were no significant sex differences in ratings of any of the perceptual measures. These results demonstrate that breast size and areolar pigmentation interact to determine ratings for a suite of sociosexual attributes, each of which may be relevant to mate choice in men and intra-sexual competition in women.

Prepubertal Serum Concentrations of Organochlorine Pesticides and Age at Sexual Maturity in Russian Boys

PubMed Central

Lam, Thuy; Williams, Paige L.; Lee, Mary M.; Korrick, Susan A.; Birnbaum, Linda S.; Burns, Jane S.; Sergeyev, Oleg; Revich, Boris; Altshul, Larisa M.; Patterson, Donald G.

2015-01-01

Background Few human studies have evaluated the impact of childhood exposure to organochlorine pesticides (OCP) on pubertal development. Objective We evaluated associations of serum OCP concentrations [hexachlorobenzene (HCB), β-hexachlorocyclohexane (βHCH), and p,p-dichlorodiphenyldichloroethylene (p,p´-DDE)] with age at attainment of sexual maturity among boys. Methods From 2003 through 2005, 350 8- to 9-year-old boys from Chapaevsk, Russia, with measured OCPs were enrolled and followed annually for 8 years. We used multivariable interval-censored models to evaluate associations of OCPs (quartiles) with three physician-assessed measures of sexual maturity: Tanner stage 5 for genitalia growth, Tanner stage 5 for pubic hair growth, or testicular volume (TV) ≥ 20 mL in either testis. Results In adjusted models, boys with higher HCB concentrations achieved sexual maturity reflected by TV ≥ 20 mL a mean of 3.1 months (95% CI: –1.7, 7.8), 5.3 months (95% CI: 0.6, 10.1), and 5.0 months (95% CI: 0.2, 9.8) later for quartiles Q2, Q3, and Q4, respectively, compared with Q1 (p trend = 0.04). Tanner stage 5 for genitalia growth was attained a mean of 2.2 months (95% CI: –3.1, 7.5), 5.7 months (95% CI: 0.4, 11.0), and 3.7 months (95% CI: –1.7, 9.1) later for quartiles Q2, Q3, and Q4, respectively, of βHCH compared with Q1 (p trend = 0.09). Tanner stage 5 for pubic hair growth occurred 6–9 months later on average for boys in the highest versus lowest quartile for HCB (p trend < 0.001), βHCH (trend p = 0.01), and p,p´-DDE (p trend = 0.04). No associations were observed between p,p´-DDE and Tanner stage 5 for genitalia growth or TV ≥ 20 mL. Conclusions and relevance Higher prepubertal serum HCB and βHCH concentrations were associated with a later age at attainment of sexual maturity. Only the highest quartile of serum p,p´-DDE was associated with later pubic hair maturation. Citation Lam T, Williams PL, Lee MM, Korrick SA, Birnbaum LS, Burns JS, Sergeyev O

Does the timing of attainment of maturity influence sexual size dimorphism and adult sex ratio in turtles?

USGS Publications Warehouse

Lovich, Jeffrey E.; Gibbons, J. Whitfield; Agha, Mickey

2014-01-01

The attainment of sexual maturity has been shown to affect measures of sexual size dimorphism (SSD) and adult sex ratios in several groups of vertebrates. Using data for turtles, we tested the model that sex ratios are expected to be male-biased when females are larger than males and female-biased when males are larger than females because of the relationship of each with the attainment of maturity. Our model is based on the premise that the earlier-maturing sex remains smaller, on average throughout life, and predominates numerically unless the sexes are strongly affected by differential mortality, differential emigration, and immigration, or biased primary sex ratios. Based on data for 24 species in seven families, SSD and sex ratios were significantly negatively correlated for most analyses, even after the effect of phylogenetic bias was removed. The analyses provide support for the model that SSD and adult sex ratios are correlated in turtles as a result of simultaneous correlation of each with sexual differences in attainment of maturity (bimaturism). Environmental sex determination provides a possible mechanism for the phenomenon in turtles and some other organisms.

[Effects of sexual maturation on body composition, dermatoglyphics, somatotype and basic physical qualities of adolescents].

PubMed

Linhares, Renato Vidal; Matta, Marcelo de Oliveira; Lima, Jorge R P; Dantas, Paulo M Silva; Costa, Mônica Barros; Fernandes Filho, José

2009-02-01

Describe the characteristics of body composition, somatotype, basic physical qualities, dermatoglyphics and bone age regarding sexual maturation stages of boys. A transversal study was carried out in 136 boys, between 10 and 14 years of age. Clinical assessment, physical examination and radiography of wrists and hands to calculate bone age were performed. A tendency of increasing total body mass, stature, body mass index, body bone diameters and muscle circumferences and basic physical qualities was found with the advancing of puberty. No differences were found in dermatoglyphics and somatotype between different stages of puberty maturation. Due to the changes in important parameters of physical training that occur during puberty, it can be concluded that the selection of children and adolescents for sport training and competitions should be based not only on chronological age but also, and mainly on sexual maturation, for better physical assessment and appropriate training for this population.

Emergence, Development, and Maturity of the Gonad of Two Species of Chitons “Sea Cockroach” (Mollusca: Polyplacophora) through the Early Life Stages

PubMed Central

Avila-Poveda, Omar Hernando; Abadia-Chanona, Quetzalli Yasú

2013-01-01

This study describes and recognises, using histological and microscopical examinations on a morphometrical basis, several gonad traits through the early life stages of Chiton articulatus and C. albolineatus. Gonadal ontogenesis, gonad development stages, sexual differentiation, onset of the first sexual maturity, and growth sequences or “early life stages” were determined. In addition, allometry between lengths and body weight pooled for both sexes per each chiton were calculated using equation Y = aXb. A total of 125 chitons (4≤TL≤40 mm, in total length “TL”) were used. All allometric relations showed a strong positive correlation (r), close to 1, with b-values above three, indicating an isometric growth. Gonadal ontogenesis and gonad development stages were categorised into three periods (“Pw” without gonad, “Pe” gonad emergence, and “Pf” gonadal sac formed) and four stages (“S0” gametocytogenesis, “S1” gametogenesis, “S2” mature, and “S3” spawning), respectively. Compound digital images were attained for each process. Periods and stages are overlapped among them and between species, with the following overall confidence intervals in TL: Pw 6.13–14.32 mm, Pe 10.32–16.93 mm, Pf 12.99–25.01 mm, S0 16.08–24.34 mm (females) and 19.51–26.60 mm (males), S1 27.15–35.63 mm (females) and 23.45–32.27 mm (males), S2 24.48–40.24 mm (females) and 25.45–32.87 mm (males). Sexual differentiation (in S0) of both chitons occurs first as a female then as a male; although, males reach the onset of the first sexual maturity earlier than females, thus for C. articulatus males at 17 mm and females at 32 mm, and for C. albolineatus males at 23.5 mm and females at 28 mm, all in TL. Four early life stages (i.e., subjuvenile, juvenile, subadult, and adult) are described and proposed to distinguish growth sequences. Our results may be useful to diverse disciplines, from developmental biology to fisheries management. PMID:23936353

Early Adolescent Sexual Activity: A Developmental Study.

ERIC Educational Resources Information Center

Whitbeck, Les B.; Yoder, Kevin A.; Hoyt, Dan R.; Conger, Rand D.

1999-01-01

Examines predictors of early sexual intercourse for a sample of 457 adolescents in grades 8 through 10, from two-parent and single-mother families. Significant decreases were noted in the effect of mother monitoring by 10th grade. The primary predictors of early intercourse were age, opportunity (steady relationship), sexually permissive attitude,…

Gonadotrophin-inhibitory hormone receptor expression in the chicken pituitary gland: potential influence of sexual maturation and ovarian steroids.

PubMed

Maddineni, S; Ocón-Grove, O M; Krzysik-Walker, S M; Hendricks, G L; Proudman, J A; Ramachandran, R

2008-09-01

Gonadotrophin-inhibitory hormone (GnIH), a hypothalamic RFamide, has been found to inhibit gonadotrophin secretion from the anterior pituitary gland originally in birds and, subsequently, in mammalian species. The gene encoding a transmembrane receptor for GnIH (GnIHR) was recently identified in the brain, pituitary gland and gonads of song bird, chicken and Japanese quail. The objectives of the present study are to characterise the expression of GnIHR mRNA and protein in the chicken pituitary gland, and to determine whether sexual maturation and gonadal steroids influence pituitary GnIHR mRNA abundance. GnIHR mRNA quantity was found to be significantly higher in diencephalon compared to either anterior pituitary gland or ovaries. GnIHR mRNA quantity was significantly higher in the pituitaries of sexually immature chickens relative to sexually mature chickens. Oestradiol or a combination of oestradiol and progesterone treatment caused a significant decrease in pituitary GnIHR mRNA quantity relative to vehicle controls. GnIHR-immunoreactive (ir) cells were identified in the chicken pituitary gland cephalic and caudal lobes. Furthermore, GnIHR-ir cells were found to be colocalised with luteinising hormone (LH)beta mRNA-, or follicle-stimulating hormone (FSH)beta mRNA-containing cells. GnIH treatment significantly decreased LH release from anterior pituitary gland slices collected from sexually immature, but not from sexually mature chickens. Taken together, GnIHR gene expression is possibly down regulated in response to a surge in circulating oestradiol and progesterone levels as the chicken undergoes sexual maturation to allow gonadotrophin secretion. Furthermore, GnIHR protein expressed in FSHbeta or LHbeta mRNA-containing cells is likely to mediate the inhibitory effect of GnIH on LH and FSH secretion.

White matter maturation profiles through early childhood predict general cognitive ability.

PubMed

Deoni, Sean C L; O'Muircheartaigh, Jonathan; Elison, Jed T; Walker, Lindsay; Doernberg, Ellen; Waskiewicz, Nicole; Dirks, Holly; Piryatinsky, Irene; Dean, Doug C; Jumbe, N L

2016-03-01

Infancy and early childhood are periods of rapid brain development, during which brain structure and function mature alongside evolving cognitive ability. An important neurodevelopmental process during this postnatal period is the maturation of the myelinated white matter, which facilitates rapid communication across neural systems and networks. Though prior brain imaging studies in children (4 years of age and above), adolescents, and adults have consistently linked white matter development with cognitive maturation and intelligence, few studies have examined how these processes are related throughout early development (birth to 4 years of age). Here, we show that the profile of white matter myelination across the first 5 years of life is strongly and specifically related to cognitive ability. Using a longitudinal design, coupled with advanced magnetic resonance imaging, we demonstrate that children with above-average ability show differential trajectories of myelin development compared to average and below average ability children, even when controlling for socioeconomic status, gestation, and birth weight. Specifically, higher ability children exhibit slower but more prolonged early development, resulting in overall increased myelin measures by ~3 years of age. These results provide new insight into the early neuroanatomical correlates of cognitive ability, and suggest an early period of prolonged maturation with associated protracted white matter plasticity may result in strengthened neural networks that can better support later development. Further, these results reinforce the necessity of a longitudinal perspective in investigating typical or suspected atypical cognitive maturation.

[Protein content in urine of male and female water vole (Arvicola amphibious) at the period of spring growth and sexual maturation].

PubMed

Nazarova, G G; Proskurniak, L P

2012-01-01

The study was carried out on the captive bread water voles Arvicola amphibious kept in vivarium. At the first decade of January, March, and June, the body length and anogenital distance were measured, the body mass was determined, and urine was collected for determination of its protein content. The obtained results have shown that the protein content depends on sex of the animals and is connected with the reproductive status of males and their dimension-weight characteristics. The urinary protein excretion level in females remained stable at different months, whereas in males its sharp rise was noted at the period of spring growth and sexual maturation. The significant sexual differences were established in March and enhanced in June. In March the urine protein content in males was noted to correlate positively with the body mass and length and with the anogenital distance. The males reached sexual maturity at the earlier calendar terms than the females did; in sexually mature males the urine protein content was significantly higher than in the sexually immature ones.

COPI selectively drives maturation of the early Golgi

PubMed Central

Papanikou, Effrosyni; Day, Kasey J; Austin, Jotham; Glick, Benjamin S

2015-01-01

COPI coated vesicles carry material between Golgi compartments, but the role of COPI in the secretory pathway has been ambiguous. Previous studies of thermosensitive yeast COPI mutants yielded the surprising conclusion that COPI was dispensable both for the secretion of certain proteins and for Golgi cisternal maturation. To revisit these issues, we optimized the anchor-away method, which allows peripheral membrane proteins such as COPI to be sequestered rapidly by adding rapamycin. Video fluorescence microscopy revealed that COPI inactivation causes an early Golgi protein to remain in place while late Golgi proteins undergo cycles of arrival and departure. These dynamics generate partially functional hybrid Golgi structures that contain both early and late Golgi proteins, explaining how secretion can persist when COPI has been inactivated. Our findings suggest that cisternal maturation involves a COPI-dependent pathway that recycles early Golgi proteins, followed by multiple COPI-independent pathways that recycle late Golgi proteins. DOI: http://dx.doi.org/10.7554/eLife.13232.001 PMID:26709839

COPI selectively drives maturation of the early Golgi

DOE Office of Scientific and Technical Information (OSTI.GOV)

Papanikou, Effrosyni; Day, Kasey J.; Austin, II, Jotham

COPI coated vesicles carry material between Golgi compartments, but the role of COPI in the secretory pathway has been ambiguous. Previous studies of thermosensitive yeast COPI mutants yielded the surprising conclusion that COPI was dispensable both for the secretion of certain proteins and for Golgi cisternal maturation. To revisit these issues, we optimized the anchor-away method, which allows peripheral membrane proteins such as COPI to be sequestered rapidly by adding rapamycin. Video fluorescence microscopy revealed that COPI inactivation causes an early Golgi protein to remain in place while late Golgi proteins undergo cycles of arrival and departure. These dynamics generatemore » partially functional hybrid Golgi structures that contain both early and late Golgi proteins, explaining how secretion can persist when COPI has been inactivated. Lastly, our findings suggest that cisternal maturation involves a COPI-dependent pathway that recycles early Golgi proteins, followed by multiple COPI-independent pathways that recycle late Golgi proteins.« less

COPI selectively drives maturation of the early Golgi

DOE PAGES

Papanikou, Effrosyni; Day, Kasey J.; Austin, II, Jotham; ...

2015-12-28

COPI coated vesicles carry material between Golgi compartments, but the role of COPI in the secretory pathway has been ambiguous. Previous studies of thermosensitive yeast COPI mutants yielded the surprising conclusion that COPI was dispensable both for the secretion of certain proteins and for Golgi cisternal maturation. To revisit these issues, we optimized the anchor-away method, which allows peripheral membrane proteins such as COPI to be sequestered rapidly by adding rapamycin. Video fluorescence microscopy revealed that COPI inactivation causes an early Golgi protein to remain in place while late Golgi proteins undergo cycles of arrival and departure. These dynamics generatemore » partially functional hybrid Golgi structures that contain both early and late Golgi proteins, explaining how secretion can persist when COPI has been inactivated. Lastly, our findings suggest that cisternal maturation involves a COPI-dependent pathway that recycles early Golgi proteins, followed by multiple COPI-independent pathways that recycle late Golgi proteins.« less

Understanding the link between early sexual initiation and later sexually transmitted infection: test and replication in two longitudinal studies.

PubMed

Epstein, Marina; Bailey, Jennifer A; Manhart, Lisa E; Hill, Karl G; Hawkins, J David; Haggerty, Kevin P; Catalano, Richard F

2014-04-01

Age at sexual initiation is strongly associated with sexually transmitted infections (STI); yet, prevention programs aiming to delay sexual initiation have shown mixed results in reducing STI. This study tested three explanatory mechanisms for the relationship between early sexual debut and STI: number of sexual partners, individual characteristics, and environmental antecedents. A test-and-replicate strategy was employed using two longitudinal studies: the Seattle Social Development Project (SSDP) and Raising Healthy Children (RHC). Childhood measures included pubertal age, behavioral disinhibition, and family, school, and peer influences. Alcohol use and age of sexual debut were measured during adolescence. Lifetime number of sexual partners and having sex under the influence were measured during young adulthood. Sexually transmitted infection diagnosis was self-reported at age 24. Early sex was defined as debut at <15 years. Path models were developed in SSDP evaluating relationships between measures, and were then tested in RHC. The relationship between early sex and STI was fully mediated by lifetime sex partners in SSDP, but only partially in RHC, after accounting for co-occurring factors. Behavioral disinhibition predicted early sex, early alcohol use, number of sexual partners, and sex under the influence, but had no direct effect on STI. Family management protected against early sex and early alcohol use, whereas antisocial peers exacerbated the risk. Early sexual initiation, a key mediator of STI, is driven by antecedents that influence multiple risk behaviors. Targeting co-occurring individual and environmental factors may be more effective than discouraging early sexual debut and may concomitantly improve other risk behaviors. Copyright © 2014 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Swimming physiology of European silver eels (Anguilla anguilla L.): energetic costs and effects on sexual maturation and reproduction.

PubMed

Palstra, Arjan P; van den Thillart, Guido E E J M

2010-09-01

The European eel migrates 5,000-6,000 km to the Sargasso Sea to reproduce. Because they venture into the ocean in a pre-pubertal state and reproduce after swimming for months, a strong interaction between swimming and sexual maturation is expected. Many swimming trials have been performed in 22 swim tunnels to elucidate their performance and the impact on maturation. European eels are able to swim long distances at a cost of 10-12 mg fat/km which is 4-6 times more efficient than salmonids. The total energy costs of reproduction correspond to 67% of the fat stores. During long distance swimming, the body composition stays the same showing that energy consumption calculations cannot be based on fat alone but need to be compensated for protein oxidation. The optimal swimming speed is 0.61-0.67 m s(-1), which is approximately 60% higher than the generally assumed cruise speed of 0.4 m s(-1) and implies that female eels may reach the Sargasso Sea within 3.5 months instead of the assumed 6 months. Swimming trials showed lipid deposition and oocyte growth, which are the first steps of sexual maturation. To investigate effects of oceanic migration on maturation, we simulated group-wise migration in a large swim-gutter with seawater. These trials showed suppressed gonadotropin expression and vitellogenesis in females, while in contrast continued sexual maturation was observed in silver males. The induction of lipid deposition in the oocytes and the inhibition of vitellogenesis by swimming in females suggest a natural sequence of events quite different from artificial maturation protocols.

Swimming physiology of European silver eels (Anguilla anguilla L.): energetic costs and effects on sexual maturation and reproduction

PubMed Central

van den Thillart, Guido E. E. J. M.

2010-01-01

The European eel migrates 5,000–6,000 km to the Sargasso Sea to reproduce. Because they venture into the ocean in a pre-pubertal state and reproduce after swimming for months, a strong interaction between swimming and sexual maturation is expected. Many swimming trials have been performed in 22 swim tunnels to elucidate their performance and the impact on maturation. European eels are able to swim long distances at a cost of 10–12 mg fat/km which is 4–6 times more efficient than salmonids. The total energy costs of reproduction correspond to 67% of the fat stores. During long distance swimming, the body composition stays the same showing that energy consumption calculations cannot be based on fat alone but need to be compensated for protein oxidation. The optimal swimming speed is 0.61–0.67 m s−1, which is ~60% higher than the generally assumed cruise speed of 0.4 m s−1 and implies that female eels may reach the Sargasso Sea within 3.5 months instead of the assumed 6 months. Swimming trials showed lipid deposition and oocyte growth, which are the first steps of sexual maturation. To investigate effects of oceanic migration on maturation, we simulated group-wise migration in a large swim-gutter with seawater. These trials showed suppressed gonadotropin expression and vitellogenesis in females, while in contrast continued sexual maturation was observed in silver males. The induction of lipid deposition in the oocytes and the inhibition of vitellogenesis by swimming in females suggest a natural sequence of events quite different from artificial maturation protocols. PMID:20390348

Early Childhood Maltreatment and Girls' Sexual Behavior: The Mediating Role of Pubertal Timing.

PubMed

Ryan, Rebecca M; Mendle, Jane; Markowitz, Anna J

2015-09-01

Although links between early childhood maltreatment and girls' sexual behavior in adolescence have been well established, it is unclear whether different forms of maltreatment are differentially associated with sexual outcomes and whether distinct mechanisms explain associations across maltreatment types. Using data from National Longitudinal Study of Adolescent Health (Add Health), the present study examines whether physical abuse, sexual abuse, and physical neglect in early childhood differentially predict girls' age at first intercourse and number of sexual partners in early adulthood. The study also tests whether early pubertal timing mediates the link between early maltreatment and sexual behavior (N = 6,364). Findings indicate that early sexual and physical abuse were equally predictive of earlier age at first intercourse and a greater number of sexual partners, but that only the sexual abuse-age at first intercourse link was mediated by early puberty. These results suggest that sexual abuse and physical abuse are associated with earlier and riskier sexual behavior in girls relative to no maltreatment and to similar degrees. However, only the link between sexual abuse and sexual behavior involves a biological mechanism manifested in early pubertal timing. Copyright © 2015 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Elevated Social Anxiety among Early Maturing Girls

ERIC Educational Resources Information Center

Blumenthal, Heidemarie; Leen-Feldner, Ellen W.; Babson, Kimberly A.; Gahr, Jessica L.; Trainor, Casey D.; Frala, Jamie L.

2011-01-01

Adolescence is a key period in terms of the development of anxiety psychopathology. An emerging literature suggests that early pubertal maturation is associated with enhanced vulnerability for anxiety symptomatology, although few studies have examined this association with regard to social anxiety. Accordingly, the current study was designed to…

Supplementary dim light differentially influences sexual maturity, oviposition time, and melatonin rhythms in pullets.

PubMed

Lewis, P D; Perry, G C; Morris, T R; English, J

2001-12-01

The addition of two 3-h periods of very dim light, one before and one after a normal 8-h photoperiod, advances sexual maturity in pullets by about a week. This trial tested the hypothesis that dim light given before a short day of normal intensity is linked to form a more stimulatory day length and that dim light given after it is photosexually ignored. Pullets were reared from 2 d of age on 8-h photoperiods. From 10 wk, they were continued on 8-h photoperiods, transferred to 16 h, or given an 8-h period of dim light (0.09 lx) immediately before or after the main 8-h photoperiod. The bright/dim and dim/ bright groups matured at the same age, thus disproving the hypothesis tested. Both groups matured 1 wk earlier than the 8-h controls but 5 wk later than birds transferred to 16-h photoperiod. Oviposition time was similar for 8-h controls and bright/dim hens and delayed by 3 h for 16-h birds, but phase advanced by 2.4 h for dim/bright hens. Plasma melatonin rhythm was phase-advanced by about 5 h in the dim/bright hens and retarded by about 5 h in the bright/dim hens, suggesting a 13-h subjective day. However, these treatments were not regarded as fully stimulatory, as a transfer to a normal 13-h photoperiod at this age advances maturity by 5 to 6 wk. These findings show that the addition of a period of dim light to a normal nonstimulatory photoperiod differentially affects the clocks that control sexual maturation, plasma melatonin concentration, and oviposition time.

Timing of Orphanhood, Early Sexual Debut, and Early Marriage in Four Sub-Saharan African Countries

PubMed Central

Chae, Sophia

2014-01-01

According to a growing body of literature, some orphans are at heightened risk of early sexual debut and early marriage. This study examines a rarely explored aspect of orphanhood: the timing and type of parental death and their relationship to these outcomes. The study also explores whether education mediates orphans’ risk of early sexual initiation and early marriage. The data are drawn from the 2004 National Survey of Adolescents, which includes interviews with 12–19-year-old adolescents in Burkina Faso, Ghana, Malawi, and Uganda. Results from discrete-time event history analysis indicate that female double orphans, regardless of timing of orphanhood, have greater odds of early sexual debut than do nonorphans. Education explains little of their increased risk. In contrast, male orphans of any type reveal no increased vulnerability to early sexual debut. Uganda is the only country where female orphans, specifically double orphans and those who are paternal orphans before age 10, have greater odds of early marriage, with education accounting for a small portion of the risk. PMID:23719999

Neuropsychological and Early Maturational Correlates of Intelligence.

ERIC Educational Resources Information Center

Denno, Deborah J.

A study designed to examine biological, sociological, and early maturational correlates of intelligence collected data prospectively, from birth to 15 years of age, on a sample of 987 black children. Multiple indicators of eight independent and three dependent variables were tested in a structural equation model. Altogether, clear sex differences…

Evidence of Late-Summer Mating Readiness and Early Sexual Maturation in Migratory Tree-Roosting Bats Found Dead at Wind Turbines

PubMed Central

Cryan, Paul M.; Jameson, Joel W.; Baerwald, Erin F.; Willis, Craig K. R.; Barclay, Robert M. R.; Snider, E. Apple; Crichton, Elizabeth G.

2012-01-01

Understanding animal mating systems is an important component of their conservation, yet the precise mating times for many species of bats are unknown. The aim of this study was to better understand the details and timing of reproductive events in species of bats that die most frequently at wind turbines in North America, because such information can help inform conservation strategies. We examined the reproductive anatomy of hoary bats (Lasiurus cinereus), eastern red bats (L. borealis), and silver-haired bats (Lasionycteris noctivagans) found dead beneath industrial-scale wind turbines to learn more about when they mate. We evaluated 103 L. cinereus, 18 L. borealis, and 47 Ln. noctivagans from wind energy facilities in the United States and Canada. Histological analysis revealed that most male L. cinereus and L. borealis, as well as over half the Ln. noctivagans examined had sperm in the caudae epididymides by late August, indicating readiness to mate. Testes regression in male hoary bats coincided with enlargement of seminal vesicles and apparent growth of keratinized spines on the glans penis. Seasonality of these processes also suggests that mating could occur during August in L. cinereus. Spermatozoa were found in the uterus of an adult female hoary bat collected in September, but not in any other females. Ovaries of all females sampled had growing secondary or tertiary follicles, indicating sexual maturity even in first-year females. Lasiurus cinereus, L. borealis, and Ln. noctivagans are the only North American temperate bats in which most first-year young of both sexes are known to sexually mature in their first autumn. Our findings provide the first detailed information published on the seasonal timing of mating readiness in these species most affected by wind turbines. PMID:23094065

Evidence of late-summer mating readiness and early sexual maturation in migratory tree-roosting bats found dead at wind turbines.

PubMed

Cryan, Paul M; Jameson, Joel W; Baerwald, Erin F; Willis, Craig K R; Barclay, Robert M R; Snider, E Apple; Crichton, Elizabeth G

2012-01-01

Understanding animal mating systems is an important component of their conservation, yet the precise mating times for many species of bats are unknown. The aim of this study was to better understand the details and timing of reproductive events in species of bats that die most frequently at wind turbines in North America, because such information can help inform conservation strategies. We examined the reproductive anatomy of hoary bats (Lasiurus cinereus), eastern red bats (L. borealis), and silver-haired bats (Lasionycteris noctivagans) found dead beneath industrial-scale wind turbines to learn more about when they mate. We evaluated 103 L. cinereus, 18 L. borealis, and 47 Ln. noctivagans from wind energy facilities in the United States and Canada. Histological analysis revealed that most male L. cinereus and L. borealis, as well as over half the Ln. noctivagans examined had sperm in the caudae epididymides by late August, indicating readiness to mate. Testes regression in male hoary bats coincided with enlargement of seminal vesicles and apparent growth of keratinized spines on the glans penis. Seasonality of these processes also suggests that mating could occur during August in L. cinereus. Spermatozoa were found in the uterus of an adult female hoary bat collected in September, but not in any other females. Ovaries of all females sampled had growing secondary or tertiary follicles, indicating sexual maturity even in first-year females. Lasiurus cinereus, L. borealis, and Ln. noctivagans are the only North American temperate bats in which most first-year young of both sexes are known to sexually mature in their first autumn. Our findings provide the first detailed information published on the seasonal timing of mating readiness in these species most affected by wind turbines.

Evidence of late-summer mating readiness and early sexual maturation in migratory tree-roosting bats found dead at wind turbines

USGS Publications Warehouse

Cryan, P.M.; Jameson, J.W.; Baerwald, E.F.; Willis, C.K.R.; Barclay, R.M.R.; Snider, E.A.; Crichton, E.G.

2012-01-01

Understanding animal mating systems is an important component of their conservation, yet the precise mating times for many species of bats are unknown. The aim of this study was to better understand the details and timing of reproductive events in species of bats that die most frequently at wind turbines in North America, because such information can help inform conservation strategies. We examined the reproductive anatomy of hoary bats (Lasiurus cinereus), eastern red bats (L. borealis), and silver-haired bats (Lasionycteris noctivagans) found dead beneath industrial-scale wind turbines to learn more about when they mate. We evaluated 103 L. cinereus, 18 L. borealis, and 47 Ln. noctivagans from wind energy facilities in the United States and Canada. Histological analysis revealed that most male L. cinereus and L. borealis, as well as over half the Ln. noctivagans examined had sperm in the caudae epididymides by late August, indicating readiness to mate. Testes regression in male hoary bats coincided with enlargement of seminal vesicles and apparent growth of keratinized spines on the glans penis. Seasonality of these processes also suggests that mating could occur during August in L. cinereus. Spermatozoa were found in the uterus of an adult female hoary bat collected in September, but not in any other females. Ovaries of all females sampled had growing secondary or tertiary follicles, indicating sexual maturity even in first-year females. Lasiurus cinereus, L. borealis, and Ln. noctivagans are the only North American temperate bats in which most first-year young of both sexes are known to sexually mature in their first autumn. Our findings provide the first detailed information published on the seasonal timing of mating readiness in these species most affected by wind turbines.

Sexual Dysfunctions: Relationship to Childhood Sexual Abuse and Early Family Experiences in a Nonclinical Sample.

ERIC Educational Resources Information Center

Kinzl, Johann F.; And Others

1995-01-01

This study evaluated 202 female university students for early familial experience and childhood sexual abuse (CSA) in relation to adult sexual disorders: (1) victims of multiple CSA more frequently reported sexual desire disorders; and (2) single-incident victims and nonvictims reported no significantly different rates of sexual dysfunction.…

Early Adolescent Perceptions Regarding Sources of Sexual Health Information

ERIC Educational Resources Information Center

Shoemaker, Kylea K.

2017-01-01

Early adolescence includes youth approximately 11-14 years of age. This age group represents a population open to learning more information about sexuality and signifies a developmental period where effective sexuality interventions may begin (Ott & Pfieffer, 2009; Grossman et al., 2014). Early adolescence is a critical period when…

Adolescent sexual behaviour, knowledge and attitudes to sexuality among school girls in Transkei, South Africa.

PubMed

Buga, G A; Amoko, D H; Ncayiyana, D J

1996-02-01

Teenagers make up a quarter of all mothers in Transkei, South Africa, and well over 75% of them are unmarried. Such a high rate of teenage pregnancy is indicative of a high level of unprotected adolescent sexual activity. We examined sexual behaviour, knowledge and attitudes to sexuality among adolescent school girls in Transkei, using a self-administered questionnaire, in order to establish the incidence of sexual activity, and associated risk factors. Of the 1072 respondents, 74.6% were already sexually experienced, and 21.0% were not. The majority of sexually experienced girls (SEGs) and sexually inexperienced girls (SIGs) were living with both their parents. There were no religious differences between the two groups of girls. The age of SEGs at first coitus correlated positively with the age of menarche, and the age at the first date, suggesting that sexual maturation and onset of dating were possible risk factors for initiation of sexual activity. Contraceptive use was low, and a third of SEGs had been pregnant at least once. The knowledge of reproductive biology among both groups of girls was generally poor, although SEGs were significantly more knowledgeable than SIGs. The majority of girls in both groups did not approve of premarital sex, and adolescent pregnancy. They also did not approve of the idea of introducing sex education in schools, or the provision of contraceptives by schools. Nearly a third of the respondents in both groups did not wish to get married in future. In conclusion, there is a high level of unprotected sexual activity among school girls in Transkei. The risk factors for this include early sexual maturation, early onset of dating, and poor knowledge of reproductive biology and contraceptives.

Which behavioral, emotional and school problems in middle-childhood predict early sexual behavior?

PubMed

Parkes, Alison; Waylen, Andrea; Sayal, Kapil; Heron, Jon; Henderson, Marion; Wight, Daniel; Macleod, John

2014-04-01

Mental health and school adjustment problems are thought to distinguish early sexual behavior from normative timing (16-18 years), but little is known about how early sexual behavior originates from these problems in middle-childhood. Existing studies do not allow for co-occurring problems, differences in onset and persistence, and there is no information on middle-childhood school adjustment in relationship to early sexual activity. This study examined associations between several middle-childhood problems and early sexual behavior, using a subsample (N = 4,739, 53 % female, 98 % white, mean age 15 years 6 months) from a birth cohort study, the Avon Longitudinal Study of Parents and Children. Adolescents provided information at age 15 on early sexual behavior (oral sex and/or intercourse) and sexual risk-taking, and at age 13 on prior risk involvement (sexual behavior, antisocial behavior and substance use). Information on hyperactivity/inattention, conduct problems, depressive symptoms, peer relationship problems, school dislike and school performance was collected in middle-childhood at Time 1 (6-8 years) and Time 2 (10-11 years). In agreement with previous research, conduct problems predicted early sexual behavior, although this was found only for persistent early problems. In addition, Time 2 school dislike predicted early sexual behavior, while peer relationship problems were protective. Persistent early school dislike further characterized higher-risk groups (early sexual behavior preceded by age 13 risk, or accompanied by higher sexual risk-taking). The study establishes middle-childhood school dislike as a novel risk factor for early sexual behavior and higher-risk groups, and the importance of persistent conduct problems. Implications for the identification of children at risk and targeted intervention are discussed, as well as suggestions for further research.

MAXIMIZING GROWTH AND SEXUAL MATURATION OF SHEEPSHEAD MINNOWS IN SUPPORT OF MULTI-GENERATION TEST DEVELOPMENT

EPA Science Inventory

Hemmer, R.L., G.M. Cripe and L.R. Goodman. In press. Maximizing Growth and Sexual Maturation of Sheepshead Minnows (Cyprinodon variegatus) in Support of Multi-Generation Test Development (Abstract). To be presented at the SETAC Fourth World Congress, 14-18 November 2004, Portland...

The vaginal microbiome is stable in prepubertal and sexually mature Ellegaard Göttingen Minipigs throughout an estrous cycle.

PubMed

Lorenzen, Emma; Kudirkiene, Egle; Gutman, Nicole; Grossi, Anette Blak; Agerholm, Jørgen Steen; Erneholm, Karin; Skytte, Christina; Dalgaard, Marlene Danner; Bojesen, Anders Miki

2015-10-28

Although the pig has been introduced as an advanced animal model of genital tract infections in women, almost no knowledge exists on the porcine vaginal microbiota, especially in barrier-raised Göttingen Minipigs. In women, the vaginal microbiota plays a crucial role for a healthy vaginal environment and the fate of sexually transmitted infections such as Chlamydia trachomatis infections. Therefore, knowledge on the vaginal microbiota is urgently needed for the minipig model. The aim of this study was to characterize the microbiota of the anterior vagina by 16 s rRNA gene sequencing in prepubertal and sexually mature Göttingen Minipigs during an estrous cycle. The dominating phyla in the vaginal microbiota consisted of Firmicutes, Proteobacteria, Actinobacteria, Bacteriodetes and Tenericutes. The most abundant bacterial families were Enterobacteriaceae, unclassified families from Gammaproteobacteria, Clostridiales Family XI Incertae Sedis, Paenibacillaceae, Lactobacillaceae, Ruminococcaceae and Syntrophaceae. We found a higher abundance of Lactobacillaceae in the prepubertal Göttingen Minipigs compared to sexually mature non-pregnant Göttingen Minipigs. However, correlation tests and diversity parameters revealed a very stable vaginal microbiota in the Göttingen Minipigs, both before and after sexual maturity and on different days throughout an estrous cycle. The vaginal microbiota in Göttingen Minipigs was not dominated by lactobacilli, as it is in women and according to our results the minipig vaginal microbiota is very stable, in opposite to women. These differences should be considered when using the minipig as a model of the genital tract in women.

Maturation and sexual ontogeny in the spangled emperor Lethrinus nebulosus.

PubMed

Marriott, R J; Jarvis, N D C; Adams, D J; Gallash, A E; Norriss, J; Newman, S J

2010-04-01

The reproductive development and sexual ontogeny of spangled emperor Lethrinus nebulosus populations in the Ningaloo Marine Park (NMP) were investigated to obtain an improved understanding of its evolved reproductive strategy and data for fisheries management. Evidence derived from (1) analyses of histological data and sampled sex ratios with size and age, (2) the identification of residual previtellogenic oocytes in immature and mature testes sampled during the spawning season and (3) observed changes in testis internal structure with increasing fish size and age, demonstrated a non-functional protogynous hermaphroditic strategy (or functional gonochorism). All the smallest and youngest fish sampled were female until they either changed sex to male at a mean 277.5 mm total length (L(T)) and 2.3 years old or remained female and matured at a larger mean L(T) (392.1 mm) and older age (3.5 years). Gonad masses were similar for males and females over the size range sampled and throughout long reproductive lives (up to a maximum estimated age of c. 31 years), which was another correlate of functional gonochorism. That the mean L(T) at sex change and female maturity were below the current minimum legal size (MLS) limit (410 mm) demonstrated that the current MLS limit is effective for preventing recreational fishers in the NMP retaining at least half of the juvenile males and females in their landed catches.

Proteomic analysis of 'Zaosu' pear (Pyrus bretschneideri Rehd.) and its early-maturing bud sport.

PubMed

Liu, Xueting; Zhai, Rui; Feng, Wenting; Zhang, Shiwei; Wang, Zhigang; Qiu, Zonghao; Zhang, Junke; Ma, Fengwang; Xu, Lingfei

2014-07-01

Maturation of fruits involves a series of physiological, biochemical, and organoleptic changes that eventually make fleshy fruits attractive, palatable, and nutritional. In order to understand the mature mechanism of the early-maturing bud sport of 'Zaosu' pear, we analyzed the differences of proteome expression between the both pears in different mature stages by the methods of a combination of two-dimensional electrophoresis (2-DE) and matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) analysis. Seventy-five differential expressed protein spots (p<0.05) were obtained between 'Zaosu' pear and its early-maturing bud sport, but only sixty-eight were demonstratively identified in the database of NCBI and uniprot. The majority of proteins were linked to metabolism, energy, stress response/defense and cell structure. Additionally, our data confirmed an increase of proteins related to cell-wall modification, oxidative stress and pentose phosphate metabolism and a decrease of proteins related to photosynthesis and glycolysis during the development process of both pears, but all these proteins increased or decreased faster in the early-maturing bud sport. This comparative analysis between both pears showed that these proteins were closely associated with maturation and could provide more detailed characteristics of the maturation process of both pears. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Early sexual debut and condom nonuse among adolescents in South Korea.

PubMed

Kim, Jiyun; Lee, Jong-Eun

2012-11-01

The purpose of this study was to investigate the factors related to sexual debut among adolescents, and to examine the association between subject characteristics and condom nonuse among those who experienced sexual intercourse in South Korea. Data were obtained from the 2009 Korean Youth Risk Behaviour Survey, a nationally representative sample. Logistic regression analysis was conducted to investigate the factors related to sexual debut, associations of condom nonuse and subject characteristics. Among male adolescents, age, early age at first emission, low academic achievement, living with a step-parent, perceived low level of household income, frequent drinking and smoking, and depressive feelings were associated with early sexual debut. Attending a coeducational school, living with a single biological parent and step-parent, risky health behaviour such as drinking and smoking, and depressive feelings were related risks factors for early sexual debut among female students. Factors associated with condom nonuse included early sexual debut (less than 16 years of age) (odds ratio (OR)=1.79, 95% confidence interval (CI)=1.32-2.43) and frequent smoking behaviour (OR=1.49, 95% CI=1.08-2.05) for males and early sexual debut (OR=4.37, 95% CI=1.02-18.68) and frequent drinking (OR=2.05, 95% CI=1.12-3.75) for females. Appropriate interventions should be implemented for adolescents in Korea to delay sexual debut and educate them on the proper use of condoms.

Early Childhood Sexuality Education: Future Educators' Attitudes and Considerations

ERIC Educational Resources Information Center

Brouskeli, Vasiliki; Sapountzis, Antonis

2017-01-01

Sexuality education is one of the most disputable health education programs as far as its inclusion in Early Childhood Education is concerned. This study was conducted in order to investigate early childhood future educators' attitudes and considerations about introducing sexuality education to their future pupils. We used a qualitative research…

Evidence for the secondary sexual development of the anal fin in female kokanee salmon Oncorhynchus nerka.

PubMed

Thorn, M W; Morbey, Y E

2016-02-01

This study examines whether the anal fin undergoes secondary sexual development similar to other reproductive traits in salmonids. This hypothesis was tested by comparing the anal-fin size of female kokanee salmon Oncorhynchus nerka that were in the early and late stages of sexual development. Females in an advanced stage of maturation had significantly larger anal fins relative to females in an early state of maturation (+4-7%), indicating that the anal fin undergoes secondary sexual development. The magnitude of this secondary growth was comparable with snout length (+9-10%), which is known to undergo secondary sexual development in female salmonids. When morphological trait dimensions were compared between the sexes, the anal fin was the only morphological trait found to have a female-biased sexual size dimorphism. This is the first study to show that the anal fin of female salmonids undergoes secondary sexual development. © 2015 The Fisheries Society of the British Isles.

Sisters’ and Girlfriends’ Sexual and Childbearing Behavior: Effects on Early Adolescent Girls’ Sexual Outcomes

PubMed Central

East, Patricia L.; Felice, Marianne E.; Morgan, Maria C.

2013-01-01

This study examined three key issues related to the effects of sisters’ and girlfriends’ sexual and childbearing behavior on early adolescent girls’ sexual outcomes. Subjects were 455 girls from predominantly minority racial backgrounds. Results indicated that number of sexually active girlfriends, number of sexually active sisters, and presence of an adolescent childbearing sister were positively associated with permissive sexual attitudes, positive intentions for future sexual activity, and a greater likelihood of being a nonvirgin. The strength of these relationships did not vary by race, but there was a greater presence of permissive social influences for African American girls than for nonblack girls. Results from multiple hierarchical regression analyses indicated that having both many sexually active girlfriends and an adolescent childbearing sister had particularly strong effects on permissive sexual attitudes and a nonvirgin status. PMID:24353349

Gender, Pubertal Development, and Peer Sexual Harassment Predict Objectified Body Consciousness in Early Adolescence

ERIC Educational Resources Information Center

Lindberg, Sara M.; Grabe, Shelly; Hyde, Janet Shibley

2007-01-01

Objectified body consciousness (OBC)--the tendency to view one's body as an object for others to look at and evaluate--is theorized to emerge during sexual maturation as adolescents, particularly adolescent girls, experience sexual objectification. Although OBC generally is discussed in developmental terms, research so far has examined primarily…

[Local injection of exogenous nerve growth factor improves early bone maturation of implants].

PubMed

Yao, Yang; Du, Yu; Gu, Xia; Guang, Meng-Kai; Huang, Bo; Gong, Ping

2018-04-01

To investigate the effects of nerve growth factor (NGF) in the osteogenic action of implants and the maturation and reconstruction changes in bone tissues in the early stage of osseointegration. The mouse implant model was established by placing titanium in the femoral head of the mouse and locally injecting NGF in the implant zone. On 1, 2 and 4 weeks after operation, stain samples were collected from animals using hematoxylin-eosin (HE) staining and Masson staining. The effect of NGF on the bone maturation was compared at different time points of early stage osseointegration. The results of HE and Masson staining indicated that the local injection of external NGF can up-regulate bone mass, amount of bone trabecula, and bone maturity in the mouse model. The mature bone rate in treatment group of 1 week and 4 weeks after operation were significantly higher than those in the control group (P<0.05). NGF can shorten the period of bone maturation.

Advanced skeletal maturity in children and adolescents with myelomeningocele.

PubMed

Roiz, Ronald; Mueske, Nicole M; Van Speybroeck, Alexander; Ryan, Deirdre D; Gilsanz, Vicente; Wren, Tishya A L

2017-12-11

Atypical skeletal development is common in youth with myelomeningocele (MM), though the underlying reasons have not been fully elucidated. This study assessed skeletal maturity in children and adolescents with MM and examined the effects of sex, age, sexual development, ethnicity, anthropometrics and shunt status. Forty-three males and 35 females with MM, 6-16 years old, underwent hand radiographs for bone age determination. The difference between bone age and chronological age was evaluated using Wilcoxon sign rank tests. Relationships between age discrepancy (skeletal-chronological) and participant characteristics were assessed using multiple linear regression with forward selection. Overall, forty percent (31/78) of MM participants had an advanced bone age of 1 year or greater (median: 2.5 years), while 47% (37/78) were within 1 year above or below their chronological age (-0.001 years) and 13% (10/78) were delayed by more than 1 year (-1.4 years). Bone age was advanced compared to chronologic age in both males and females (p⩽ 0.024). Advanced bone age was observed in early to late puberty and after maturation (p⩽ 0.07), as well as in Hispanic participants (p= 0.003) and in those with a shunt (p= 0.0004). Advanced bone age was positively correlated with height, weight and body mass index (BMI) percentiles (p= 0.004). In multiple linear regression analysis, advanced bone age was most strongly associated with higher Tanner stage of sexual development, and higher weight, height or BMI percentile. Advanced skeletal maturity is common in children/adolescents with MM over 8 years of age who have reached puberty (65%), particularly those who are overweight (80%). Hormonal effects associated with adiposity and sexual maturity likely influence skeletal maturation. Clinicians may use Tanner stage and weight or BMI to gain insight into skeletal maturity.

Pubertal timing and sexual risk behaviors among rural African American male youth: testing a model based on life history theory.

PubMed

Kogan, Steven M; Cho, Junhan; Simons, Leslie Gordon; Allen, Kimberly A; Beach, Steven R H; Simons, Ronald L; Gibbons, Frederick X

2015-04-01

Life History Theory (LHT), a branch of evolutionary biology, describes how organisms maximize their reproductive success in response to environmental conditions. This theory suggests that challenging environmental conditions will lead to early pubertal maturation, which in turn predicts heightened risky sexual behavior. Although largely confirmed among female adolescents, results with male youth are inconsistent. We tested a set of predictions based on LHT with a sample of 375 African American male youth assessed three times from age 11 to age 16. Harsh, unpredictable community environments and harsh, inconsistent, or unregulated parenting at age 11 were hypothesized to predict pubertal maturation at age 13; pubertal maturation was hypothesized to forecast risky sexual behavior, including early onset of intercourse, substance use during sexual activity, and lifetime numbers of sexual partners. Results were consistent with our hypotheses. Among African American male youth, community environments were a modest but significant predictor of pubertal timing. Among those youth with high negative emotionality, both parenting and community factors predicted pubertal timing. Pubertal timing at age 13 forecast risky sexual behavior at age 16. Results of analyses conducted to determine whether environmental effects on sexual risk behavior were mediated by pubertal timing were not significant. This suggests that, although evolutionary mechanisms may affect pubertal development via contextual influences for sensitive youth, the factors that predict sexual risk behavior depend less on pubertal maturation than LHT suggests.

Puberty: Maturation, Timing and Adjustment, and Sexual Identity Developmental Milestones among Lesbian, Gay, and Bisexual Youth

ERIC Educational Resources Information Center

Grossman, Arnold H.; Foss, Alexander H.; D'Augelli, Anthony R.

2014-01-01

This study examined pubertal maturation, pubertal timing and outcomes, and the relationship of puberty and sexual identity developmental milestones among 507 lesbian, gay, and bisexual youth. The onset of menarche and spermarche occurred at the mean ages of 12.05 and 12.46, respectively. There was no statistically significant difference in…

Effect of sexual maturation on thermal stability, viscoelastic properties, and texture of rainbow trout, Oncorhynchus mykiss, fillets

USDA-ARS?s Scientific Manuscript database

The nutrient and energy demand of sexual maturation in many fish cultivars causes structural change to key contractile proteins and thereby, affects fillet firmness. Thermal denaturation and viscoelastic properties of white muscle from diploid (2N; fertile) and triploid (3N; sterile) female rainbow...

Early Sexual Intercourse: Prospective Associations with Adolescents Physical Activity and Screen Time

PubMed Central

Wijtzes, Anne; van de Bongardt, Daphne; van de Looij-Jansen, Petra; Bannink, Rienke; Raat, Hein

2016-01-01

Objectives To assess the prospective associations of physical activity behaviors and screen time with early sexual intercourse initiation (i.e., before 15 years) in a large sample of adolescents. Methods We used two waves of data from the Rotterdam Youth Monitor, a longitudinal study conducted in the Netherlands. The analysis sample consisted of 2,141 adolescents aged 12 to 14 years (mean age at baseline = 12.2 years, SD = 0.43). Physical activity (e.g., sports outside school), screen time (e.g., computer use), and early sexual intercourse initiation were assessed by means of self-report questionnaires. Logistic regression models were tested to assess the associations of physical activity behaviors and screen time (separately and simultaneously) with early sexual intercourse initiation, controlling for confounders (i.e., socio-demographics and substance use). Interaction effects with gender were tested to assess whether these associations differed significantly between boys and girls. Results The only physical activity behavior that was a significant predictor of early sexual intercourse initiation was sports club membership. Adolescent boys and girls who were members of a sports club) were more likely to have had early sex (OR = 2.17; 95% CI = 1.33, 3.56. Significant gender interaction effects indicated that boys who watched TV ≥2 hours/day (OR = 2.00; 95% CI = 1.08, 3.68) and girls who used the computer ≥2 hours/day (OR = 3.92; 95% CI = 1.76, 8.69) were also significantly more likely to have engaged in early sex. Conclusion These findings have implications for professionals in general pediatric healthcare, sexual health educators, policy makers, and parents, who should be aware of these possible prospective links between sports club membership, TV watching (for boys), and computer use (for girls), and early sexual intercourse initiation. However, continued research on determinants of adolescents’ early sexual initiation is needed to further contribute to

Association between early sexual abuse and adult HIV-risky sexual behaviors among community-recruited women.

PubMed

Parillo, K M; Freeman, R C; Collier, K; Young, P

2001-03-01

The first purpose was to determine whether sexual abuse involving penetration that occurred in childhood only, adolescence only, or both childhood and adolescence differently impacted whether community-recruited women had ever traded sex for money or drugs, their number of recent sex partners, and the number of times they had engaged in recent unprotected sex. The second purpose was to assess the mediating effects of adulthood rape, recent drug use, and recent sex with an injection drug user on these three HIV-risky sexual behaviors. Women (n = 1,490) recruited from three US sites were questioned about their childhood and/or adolescent sexual abuse histories, adulthood rape experiences, recent drug use, and adult HIV-risky sexual behaviors via structured interviews. One-third of the women reported having experienced sexual abuse involving penetration in childhood and/or adolescence. Overall, regression analyses indicated a significant relationship between early sexual abuse and adult risky behaviors; rape in adulthood mediated this relationship for all three HIV-risky behaviors. Abuse that occurred in childhood only and abuse that occurred in both childhood and adolescence had a stronger impact on later risky behaviors than did abuse that occurred in adolescence only. Because childhood constitutes a critical period in individuals' sexual, social, and personal development, sexual abuse precipitated during this time may distort women's constructions of sex and sexuality. Women abused in childhood may therefore engage in HIV-risky sexual behaviors to a greater extent than women abused in adolescence as a result of these disruptions to their development. Rape in adulthood appears to intensify the effects of early sexual abuse,

Temporal changes in the expression of avian β-defensins in the chicken vagina during sexual maturation and Salmonella infection.

PubMed

Anastasiadou, Maria; Avdi, Melpomeni; Theodoridis, Alexandros; Michailidis, Georgios

2013-06-01

Avian β-defensins (AvβDs) constitute a family of antimicrobial peptides that are critical to innate immunity in chickens, providing protection against microbial pathogens including Salmonella Enteritidis (SE). As apart from the digestive tract another main route of SE colonization in birds is via infection of the oviduct and specifically of the vagina, the aim of this study was to investigate the expression of the complete family of AvβDs, in the chicken vagina in vivo, to determine whether sexual maturation affects their mRNA abundance and to investigate whether SE infection alters the vaginal AvβDs expression. Expression analysis revealed that 11 members of the AvβD family were expressed in the chicken vagina. Quantitative real-time PCR analysis revealed that the mRNA abundance of five AvβDs was up regulated and of one AvβD was down regulated with respect to sexual maturation. In addition SE infection resulted in a significant induction of AvβD5, 7, 10, 11, 12 and 14 in the vagina of sexually mature birds, and in a significant induction of AvβD5 and 11 in the vagina of aged birds. These findings provide strong evidence to suggest that an AvβD-mediated immune response mechanism exists in the chicken vagina providing protection against bacterial pathogens including Salmonella species.

Comparative biology of the crab Goniopsis cruentata: geographic variation of body size, sexual maturity, and allometric growth

NASA Astrophysics Data System (ADS)

de Lira, José Jonathas Pereira Rodrigues; Calado, Tereza Cristina dos Santos; Rezende, Carla Ferreira; Silva, José Roberto Feitosa

2015-12-01

Geographic variation of phenotypic traits is common across species and is often associated with variation in environmental conditions. Here, we found larger bodies and larger size at maturity in a northward, lower latitude population of the crab Goniopsis cruentata, which inhabits a hotter, drier environment in comparison with a southward, higher latitude population. Furthermore, the juvenile male gonopods grow more relative to body size in the population characterized by maturation at a smaller size. In contrast, the female abdomen widens at a higher rate among the late maturing population. These results provide further evidence that local environmental conditions play a role in phenotypic variation between populations inhabiting different latitudes. Moreover, they also show that variation in size at maturity and body size can lead to divergent allometric patterns of sexual characteristics that can have a sex-specific response.

Prepubertal exposure to arsenic(III) suppresses circulating insulin-like growth factor-1 (IGF-1) delaying sexual maturation in female rats.

PubMed

Reilly, Michael P; Saca, James C; Hamilton, Alina; Solano, Rene F; Rivera, Jesse R; Whitehouse-Innis, Wendy; Parsons, Jason G; Dearth, Robert K

2014-04-01

Arsenic (As) is a prevalent environmental toxin readily accessible for human consumption and has been identified as an endocrine disruptor. However, it is not known what impact As has on female sexual maturation. Therefore, in the present study, we investigated the effects of prepubertal exposure on mammary gland development and pubertal onset in female rats. Results showed that prepubertal exposure to 10 mg/kg of arsenite (As(III)) delayed vaginal opening (VO) and prepubertal mammary gland maturation. We determined that As accumulates in the liver, disrupts hepatocyte function and suppresses serum levels of the puberty related hormone insulin-like growth factor 1 (IGF-1) in prepubertal animals. Overall, this is the first study to show that prepubertal exposure to As(III) acts peripherally to suppress circulating levels of IGF-1 resulting in delayed sexual maturation. Furthermore, this study identifies a critical window of increased susceptibility to As(III) that may have a lasting impact on female reproductive function. Copyright © 2013 Elsevier Inc. All rights reserved.

The Development of the Sexual Self-Concept Inventory for Early Adolescent Girls

ERIC Educational Resources Information Center

O'Sullivan, Lucia F.; Meyer-Bahlburg, Heino F. L.; McKeague, Ian W.

2006-01-01

The Sexual Self-Concept Inventory (SSCI) was developed to assess sexual self-concept in an ethnically diverse sample of urban early adolescent girls. Three scales (Sexual Arousability, Sexual Agency, and Negative Sexual Affect) were shown to be distinct and reliable dimensions of girls' sexual self-concepts. Validity was established through…

Depressive symptoms among Hong Kong adolescents: relation to atypical sexual feelings and behaviors, gender dissatisfaction, pubertal timing, and family and peer relationships.

PubMed

Lam, T H; Stewart, Sunita M; Leung, Gabriel M; Lee, Peter W H; Wong, Joy P S; Ho, L M; Youth Sexuality Task Force

2004-10-01

A representative community sample of Hong Kong boys (n = 1,024) and girls (n = 1,403), age 14-18 years, provided information regarding same-sex attraction, gender dissatisfaction, pubertal timing, early experience with sexual intercourse, and depressive symptoms. They also rated the quality of their family and peer relationships and self-perceived attractiveness. Depressive symptoms were higher in youths reporting same-sex attraction, gender dissatisfaction, early pubertal maturation, and early sexual intercourse. Family relationships were less satisfactory for those who reported same-sex attraction, gender dissatisfaction, and early sexual intercourse, and peer relationships were also worse for those who reported gender dissatisfaction. In multivariate analyses, same-sex attraction, early sexual intercourse, and early pubertal maturation were unique and direct contributors to depressive symptoms; however, gender dissatisfaction's association with depressive symptoms was largely accounted for by shared correlations with negative family and peer relationships. The multivariate model explained 11% of the variance of depressive symptoms. These findings offer a preliminary documentation of the prevalence and correlates of atypical sexual self-assessments and behavior among adolescents in Hong Kong. Such information is important if theories of sexual identity and risk factors for depressive symptoms are to have cross-cultural utility. Copyright 2004 Springer Science + Business Media, Inc.

Transcriptional changes of cytokines in rooster testis and epididymis during sexual maturation stages and Salmonella infection.

PubMed

Anastasiadou, M; Michailidis, G

2016-08-01

Infection of rooster testis and epididymis by pathogens can lead to impaired fertility, resulting in economic losses in the poultry industry. Antimicrobial protection of rooster reproductive organs is, therefore, an important aspect of reproductive physiology. Salmonellosis is one of the most important zoonotic diseases, caused by Salmonella bacteria including Salmonella Enteritidis (SE) and is usually the result of infection of the reproductive organs. Thus, knowledge of the endogenous innate immune mechanisms of the rooster testis and epididymis is an emerging aspect of reproductive physiology. Cytokines are key factors for stimulating the immune response and inflammation in chickens to Salmonella infection. In the present study the expression profile of 11 pro-inflammatory cytokine genes in the rooster testis and epididymis in vivo and transcriptional changes in these organs during sexual maturation and SE infection were investigated. Gene expression analysis data revealed that in both testis and epididymis nine cytokines namely the IL-1β, IL-6, IL-8, IL-10, IL-12, IL-15, IL-16, IL-17 and IL-18 genes were expressed, while no mRNA transcripts were detected in both organs for IL-2 and IL-4. Furthermore, the expression of various cytokine genes during sexual maturation appeared to be developmentally regulated, while SE infection resulted in a significant up-regulation of IL-1β, -6, -12 and -18 genes in the testis and an increase in the mRNA relative abundance of IL-1β, -6, -12, -16 and -18 in the epididymis of SE-infected sexually mature 28-week-old roosters. These results suggest a cytokine-mediated immune response mechanism against Salmonella infection in the rooster reproductive tract. Copyright © 2016 Elsevier B.V. All rights reserved.

Kisspeptin regulates the hypothalamus-pituitary-gonad axis gene expression during sexual maturation in the cinnamon clownfish, Amphiprion melanopus.

PubMed

Kim, Na Na; Shin, Hyun Suk; Choi, Young Jae; Choi, Cheol Young

2014-02-01

Kisspeptins (Kiss) have been recognized as potent regulators of reproduction in teleosts, and Kiss is suggested to be a key regulator of the hypothalamus-pituitary-gonad axis (HPG). However, its regulatory role on reproduction in fish remains unclear. Therefore, to investigate the role of Kiss on fish reproduction, this study aimed to test differences in the hormones of the HPG axis, Kiss as neuropeptides, and sex steroids on the sexual maturation of paired cinnamon clownfish, Amphiprion melanopus, following treatment with Kiss. We investigated the actions of sex maturation hormones, including HPG axis hormones and sex steroid hormones, such as gonadotropin-releasing hormones, gonadotropin hormones (GTHs), GTH receptors, estrogen receptors, and vitellogenin in the pituitary, gonads, and liver following treatment with Kiss. The expression levels of HPG axis genes increased after the Kiss injection. In addition, the levels of plasma 17α-hydroxypregnenolone, estradiol-17β, and 11-ketotestosterone increased. These results support the hypothesis that Kiss play important roles in the regulation of the HPG axis and are most likely involved in gonadal development and sexual maturation in cinnamon clownfish. Copyright © 2013 Elsevier Inc. All rights reserved.

Early Adolescent Sexual Initiation as a Problem Behavior: A Comparative Study of Five Nations

PubMed Central

Madkour, Aubrey Spriggs; Farhat, Tilda; Halpern, Carolyn Tucker; Godeau, Emmanuelle; Gabhainn, Saoirse Nic

2010-01-01

Purpose Using a Problem Behavior Theory (PBT) framework, this paper examines the extent to which psychosocial correlates of early sexual initiation (before age 16) vary across developed nations. Methods Fifteen-year-old participants (n=5,624) in the 1997-1998 WHO collaborative Health Behavior in School-Aged Children survey (Finland, Scotland, France and Poland) and the 1996 US Add Health survey self-reported substance use (alcohol and tobacco), school attachment, positive parental communication, and early sexual intercourse experience. Stratifying by gender, we performed univariate, bivariate, and multivariable analyses controlling for family socioeconomic status, family structure, and nation fixed effects. Results Self-reported early sexual experience, substance use, school attachment and positive communication with parents varied significantly across nations for both boys and girls. In both crude and adjusted analyses, substance use was positively associated with early sexual experience among boys and girls across nations, although associations were stronger in Europe than the US (adjusted odds ratio [AOR] range 1.56-3.74). School attachment was similarly inversely related to early sexual experience among boys and girls across nations (AOR range 0.63-0.94). However, positive parent communication was significantly inversely related to early sexual experience only among US females (AOR 0.50). Conclusions Findings overall supported the fit of early adolescent sexual initiation as a risk behavior within a PBT framework cross-nationally, suggesting that similar factors could be targeted to prevent early sexual initiation across some developed nations. However further research is warranted examining the temporality of these relationships. PMID:20864009

Plasma Cholesterol–Induced Lesion Networks Activated before Regression of Early, Mature, and Advanced Atherosclerosis

PubMed Central

Björkegren, Johan L. M.; Hägg, Sara; Jain, Rajeev K.; Cedergren, Cecilia; Shang, Ming-Mei; Rossignoli, Aránzazu; Takolander, Rabbe; Melander, Olle; Hamsten, Anders; Michoel, Tom; Skogsberg, Josefin

2014-01-01

Plasma cholesterol lowering (PCL) slows and sometimes prevents progression of atherosclerosis and may even lead to regression. Little is known about how molecular processes in the atherosclerotic arterial wall respond to PCL and modify responses to atherosclerosis regression. We studied atherosclerosis regression and global gene expression responses to PCL (≥80%) and to atherosclerosis regression itself in early, mature, and advanced lesions. In atherosclerotic aortic wall from Ldlr−/−Apob 100/100 Mttp flox/floxMx1-Cre mice, atherosclerosis regressed after PCL regardless of lesion stage. However, near-complete regression was observed only in mice with early lesions; mice with mature and advanced lesions were left with regression-resistant, relatively unstable plaque remnants. Atherosclerosis genes responding to PCL before regression, unlike those responding to the regression itself, were enriched in inherited risk for coronary artery disease and myocardial infarction, indicating causality. Inference of transcription factor (TF) regulatory networks of these PCL-responsive gene sets revealed largely different networks in early, mature, and advanced lesions. In early lesions, PPARG was identified as a specific master regulator of the PCL-responsive atherosclerosis TF-regulatory network, whereas in mature and advanced lesions, the specific master regulators were MLL5 and SRSF10/XRN2, respectively. In a THP-1 foam cell model of atherosclerosis regression, siRNA targeting of these master regulators activated the time-point-specific TF-regulatory networks and altered the accumulation of cholesterol esters. We conclude that PCL leads to complete atherosclerosis regression only in mice with early lesions. Identified master regulators and related PCL-responsive TF-regulatory networks will be interesting targets to enhance PCL-mediated regression of mature and advanced atherosclerotic lesions. PMID:24586211

Child abuse, early maladaptive schemas, and risky sexual behavior in college women.

PubMed

Roemmele, Melissa; Messman-Moore, Terri L

2011-05-01

Previous research suggests that individuals abused as children are more likely to engage in risky sexual behavior during adulthood. The present study examined early maladaptive schemas as mediators of the child abuse-risky sexual behavior relationship among 653 college women. Self-report surveys assessed three forms of child abuse: Sexual, physical, and emotional, and assessed early maladaptive schemas within two domains: Disconnection/rejection and Other-Directedness. Disconnection/rejection schemas fully mediated the relation between child emotional abuse and number of sexual partners and partially mediated the relationship for sexual and physical abuse. However, when frequency of specific risky sexual acts (e.g., sex without contraception) was examined in the previous six months, only abandonment was a partial mediator. Implications for intervention and future research are discussed.

Structural and Maturational Covariance in Early Childhood Brain Development.

PubMed

Geng, Xiujuan; Li, Gang; Lu, Zhaohua; Gao, Wei; Wang, Li; Shen, Dinggang; Zhu, Hongtu; Gilmore, John H

2017-03-01

Brain structural covariance networks (SCNs) composed of regions with correlated variation are altered in neuropsychiatric disease and change with age. Little is known about the development of SCNs in early childhood, a period of rapid cortical growth. We investigated the development of structural and maturational covariance networks, including default, dorsal attention, primary visual and sensorimotor networks in a longitudinal population of 118 children after birth to 2 years old and compared them with intrinsic functional connectivity networks. We found that structural covariance of all networks exhibit strong correlations mostly limited to their seed regions. By Age 2, default and dorsal attention structural networks are much less distributed compared with their functional maps. The maturational covariance maps, however, revealed significant couplings in rates of change between distributed regions, which partially recapitulate their functional networks. The structural and maturational covariance of the primary visual and sensorimotor networks shows similar patterns to the corresponding functional networks. Results indicate that functional networks are in place prior to structural networks, that correlated structural patterns in adult may arise in part from coordinated cortical maturation, and that regional co-activation in functional networks may guide and refine the maturation of SCNs over childhood development. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Antennal proteome comparison of sexually mature drone and forager honeybees.

PubMed

Feng, Mao; Song, Feifei; Aleku, Dereje Woltedji; Han, Bin; Fang, Yu; Li, Jianke

2011-07-01

Honeybees have evolved an intricate system of chemical communication to regulate their complex social interactions. Specific proteins involved in odorant detection most likely supported this chemical communication. Odorant reception takes place mainly in the antennae within hairlike structures called olfactory sensilla. Antennal proteomes of sexually mature drone and forager worker bees (an age group of bees assigned to perform field tasks) were compared using two-dimensional electrophoresis, mass spectrometry, quantitative real-time polymerase chain reaction, and bioinformatics. Sixty-one differentially expressed proteins were identified in which 67% were highly upregulated in the drones' antennae whereas only 33% upregulated in the worker bees' antennae. The antennae of the worker bees strongly expressed carbohydrate and energy metabolism and molecular transporters signifying a strong demand for metabolic energy and odorant binding proteins for their foraging activities and other olfactory responses, while proteins related to fatty acid metabolism, antioxidation, and protein folding were strongly upregulated in the drones' antennae as an indication of the importance for the detection and degradation of sex pheromones during queen identification for mating. On the basis of both groups of altered antenna proteins, carbohydrate metabolism and energy production and molecular transporters comprised more than 80% of the functional enrichment analysis and 45% of the constructed biological interaction networks (BIN), respectively. This suggests these two protein families play crucial roles in the antennal olfactory function of sexually mature drone and forager worker bees. Several key node proteins in the BIN were validated at the transcript level. This first global proteomic comparative analysis of antennae reveals sex-biased protein expression in both bees, indicating that odorant response mechanisms are sex-specific because of natural selection for different olfactory

Effects of feed quality and quantity on growth, early maturation and smolt development in hatchery-reared landlocked Atlantic salmon Salmo salar.

PubMed

Norrgård, J R; Bergman, E; Greenberg, L A; Schmitz, M

2014-10-01

The effects of feed quality and quantity on growth, early male parr maturation and development of smolt characteristics were studied in hatchery-reared landlocked Atlantic salmon Salmo salar. The fish were subjected to two levels of feed rations and two levels of lipid content from first feeding until release in May of their second year. Salmo salar fed high rations, regardless of lipid content, grew the most and those fed low lipid feed with low rations grew the least. In addition, fish fed low lipid feed had lower body lipid levels than fish fed high lipid feed. Salmo salar from all treatments showed some reduction in condition factor (K) and lipid levels during their second spring. Smolt status was evaluated using both physiological and morphological variables. These results, based on gill Na(+) , K(+) -ATPase (NKA) enzyme activity, saltwater tolerance challenges and visual assessments, were consistent with each other, showing that S. salar from all treatments, except the treatment in which the fish were fed low rations with low lipid content, exhibited characteristics associated with smolting at 2 years of age. Sexually mature male parr from the high ration, high lipid content treatment were also subjected to saltwater challenge tests, and were found to be unable to regulate plasma sodium levels. The proportion of sexually mature male parr was reduced when the fish were fed low feed rations, but was not affected by the lipid content of the feed. Salmo salar fed low rations with low lipid content exhibited the highest degree of severe fin erosion. © 2014 The Fisheries Society of the British Isles.

Maturity status of youth football players: a noninvasive estimate.

PubMed

Malina, Robert M; Cumming, Sean P; Morano, Peter J; Barron, Mary; Miller, Susan J

2005-06-01

To estimate the biological maturity status of youth football players 9-14 yr old using a noninvasive method and to compare the body size of players of contrasting status. Subjects were members of youth football teams in two central Michigan communities. Height and weight were measured on 653 boys 8.7-14.6 yr. Heights of biological parents of 582 boys were reported and subsequently adjusted for overestimation. Decimal age, height, and weight of the player and midparent height were used to predict mature (adult) height for the boy. Current height of each player was expressed as a percentage of his predicted mature height to provide an estimate of biological maturity status. Percentage of predicted mature height of each boy was expressed as a z-score to classify players into maturity groups. ANCOVA, controlling for age, was used to compare body size in contrasting maturity groups. Mean percentages of predicted mature height of the players matched those of longitudinal reference samples, but there was a trend for higher percentages among older players, suggesting advanced maturation. Overall, 405 boys were classified as on time/average in maturity status (69.6% [95%CI 65.7-73.3]), 154 were classified as early/advanced (25.5% [95%CI 23.0-30.3]), and only 23 were classified as late/delayed (3.9% [95%CI 2.6-6.0]). The gradient for height, weight, and BMI was as follows: early > on time > late, and differences were greater for weight and the BMI than for height. Percentage of predicted mature height attained at a given age appears to be a reasonable indicator of maturity status. The method needs to be validated with other more direct indicators (skeletal age, sexual maturation) and applied to other samples.

Early sexual debut among young men in rural South Africa: heightened vulnerability to sexual risk?

PubMed Central

Harrison, A; Cleland, J; Gouws, E; Frohlich, J

2005-01-01

Methods: Analysis of sexual behaviour data for men 15–24 years (n = 314) from representative cross sectional household survey. Results: 13.1% of 15–24 year old men experienced sexual debut before age 15. Men with sexual debut at less than age 15 were more likely to report risk behaviours at first sexual experience: no condom use (19%), a casual partner (26.8%), and not feeling they had been "ready and wanted to have sex" (19.5%). In multivariate analysis, early sexual debut was strongly associated with ⩾3 partners in the past 3 years (OR = 10.26, p<0.01). Conclusions: Men who initiate sex before age 15 form a distinct risk group in this setting. Specific interventions are needed for young men in the preteen years, before sexual debut. PMID:15923298

Mother-Daughter Communication about Sexual Maturation, Abstinence and Unintended Pregnancy: Experiences from an Informal Settlement in Nairobi, Kenya

ERIC Educational Resources Information Center

Crichton, Joanna; Ibisomi, Latifat; Gyimah, Stephen Obeng

2012-01-01

Parental communication and support is associated with improved developmental, health and behavioral outcomes in adolescence. This study explores the quality of mother-daughter communication about sexual maturation, abstinence and unintended pregnancy in Korogocho, an informal settlement in Nairobi, Kenya. We use data from 14 focus group…

Peer and Teacher Effects on the Early Onset of Sexual Intercourse

PubMed Central

Brendgen, Mara; Wanner, Brigitte; Vitaro, Frank

2007-01-01

Objectives. We examined the links between peer rejection and verbal abuse by a teacher during childhood with the early onset of sexual intercourse and the mediating role of delinquent behavior and low self-esteem in this context. Methods. We assessed 312 students (159 girls) in northwestern Quebec annually from kindergarten through seventh grade. Peer identifications were used to assess peer rejection and verbal abuse by teachers from kindergarten through fourth grade. In seventh grade, self-reports were used to assess delinquent behavior, self-esteem, and having sexual intercourse. Multiple sources were used to assess control variables. Results. Multiple imputation-based linear and logistic regressions showed that peer rejection was indirectly associated with a higher risk of early intercourse by its link with lower self-esteem, but only for girls. Verbal abuse by teachers during childhood was directly associated with a higher risk of early sexual intercourse and indirectly by its link with delinquent behavior. Conclusions. The results underline the importance of both peers and teachers in healthy sexual development among youths, especially for girls, and emphasize the need for targeted health and sexual education programs. PMID:17901435

Early parenting styles and sexual offending behavior: A comparative study.

PubMed

Sigre-Leirós, Vera; Carvalho, Joana; Nobre, Pedro J

2016-01-01

Sexual offenders, in general, report problematic rearing practices from their parents, lacking however more empirical research on this topic regarding particular subtypes of offenders. The current study examined the relationship between early parenting styles and different types of sexual offending. A total of 113 sexual offenders (rapists, pedophilic and nonpedophilic child molesters), and 51 nonsexual offenders completed the EMBU (My Memories of Upbringing), the Brief Symptom Inventory, and the Socially Desirable Response Set Measure. Results showed that rapists were less likely to remember their fathers as being emotionally warm compared with nonsexual offenders and pedophilic child molesters. In addition, compared with rapists, pedophilic offenders perceived their mothers as having been less emotionally warm to them. Overall, results showed that certain developmental experiences with parents were able to distinguish between subtypes of offenders supporting an association between distal interpersonal factors and sexual offending. These findings may have important implications for early intervention and prevention of sexual crimes. Further research using larger samples of pedophilic child molesters is recommended. Copyright © 2016 Elsevier Ltd. All rights reserved.

Pubertal Timing and Early Sexual Intercourse in the Offspring of Teenage Mothers

ERIC Educational Resources Information Center

De Genna, Natacha M.; Larkby, Cynthia; Cornelius, Marie D.

2011-01-01

Early puberty is associated with stressful family environments, early sexual intercourse, and teenage pregnancy. We examined pubertal timing and sexual debut among the 14-year-old offspring of teenage mothers. Mothers (71% Black, 29% White) were recruited as pregnant teenagers (12-18 years old). Data were collected during pregnancy and when…

Are sexual media exposure, parental restrictions on media use and co-viewing TV and DVDs with parents and friends associated with teenagers' early sexual behaviour?

PubMed

Parkes, Alison; Wight, Daniel; Hunt, Kate; Henderson, Marion; Sargent, James

2013-12-01

Sexual content in teenagers' media diets is known to predict early sexual behaviour. Research on sexual content has not allowed for the social context of media use, which may affect selection and processing of content. This study investigated whether sexual media content and/or contextual factors (co-viewing, parental media restrictions) were associated with early sexual behaviour using 2251 14-15 year-olds from Scotland, UK. A third (n = 733) reported sexual intercourse. In multivariable analysis the likelihood of intercourse was lower with parental restriction of sexual media and same-sex peer co-viewing; but higher with mixed-sex peer co-viewing. Parental co-viewing, other parental restrictions on media and sexual film content exposure were not associated with intercourse. Findings suggest the context of media use may influence early sexual behaviour. Specific parental restrictions on sexual media may offer more protection against early sex than other restrictions or parental co-viewing. Further research is required to establish causal mechanisms. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

Soy protein supplement intake for 12 months has no effect on sexual maturation and may improve nutritional status in pre-pubertal children.

PubMed

Duitama, Sandra M; Zurita, Javier; Cordoba, Diana; Duran, Paola; Ilag, Leopold; Mejia, Wilson

2018-05-20

To evaluate the intake of a soy protein-based supplement (SPS) and its effects on the sexual maturation and nutritional status of prepubertal children who consumed it for a year. Healthy children (n = 51) were recruited and randomly assigned to consume the lunch fruit juice with (n = 29) or without (n = 22) addition of 45 g of a commercial soy protein-based supplement (SPS) over 12 months. Nutritional assessment including anthropometry (bodyweight, height, triceps skinfold thickness, mid-upper arm circumference), body mass index (BMI), upper arm muscle area, arm muscle circumference, upper arm area, upper arm fat area data were derived from measures using usual procedures; age and gender-specific percentiles were used as reference. Sexual maturation was measured by Tanner stage. Isoflavones were quantified using liquid chromatography and tandem mass spectrometry. Height, BMI/age, weight/age and height/age were significantly different (P < 0.05) at 12 months between girls in the control and intervention groups. Statistically significant differences between groups by gender (P < 0.05) were found in boys in the control group for the triceps skinfold thickness and fat area. Nutritional status was adequate according to the World Health Organization parameters. On average, 0.130 mg/kg body weight/day of isoflavones were consumed by children, which did not show significant differences in their sexual maturation. Consumption of SPS for 12 months did not affect sexual maturation or the onset of puberty in prepubertal boys and girls; however, it may have induced an increase in height, BMI/age, height/age and weight/age of the girls, associated with variations in fat-free mass. © 2018 Paediatrics and Child Health Division (The Royal Australasian College of Physicians).

Auditory experience controls the maturation of song discrimination and sexual response in Drosophila

PubMed Central

Li, Xiaodong; Ishimoto, Hiroshi

2018-01-01

In birds and higher mammals, auditory experience during development is critical to discriminate sound patterns in adulthood. However, the neural and molecular nature of this acquired ability remains elusive. In fruit flies, acoustic perception has been thought to be innate. Here we report, surprisingly, that auditory experience of a species-specific courtship song in developing Drosophila shapes adult song perception and resultant sexual behavior. Preferences in the song-response behaviors of both males and females were tuned by social acoustic exposure during development. We examined the molecular and cellular determinants of this social acoustic learning and found that GABA signaling acting on the GABAA receptor Rdl in the pC1 neurons, the integration node for courtship stimuli, regulated auditory tuning and sexual behavior. These findings demonstrate that maturation of auditory perception in flies is unexpectedly plastic and is acquired socially, providing a model to investigate how song learning regulates mating preference in insects. PMID:29555017

Are sexual media exposure, parental restrictions on media use and co-viewing TV and DVDs with parents and friends associated with teenagers' early sexual behaviour?☆

PubMed Central

Parkes, Alison; Wight, Daniel; Hunt, Kate; Henderson, Marion; Sargent, James

2013-01-01

Sexual content in teenagers' media diets is known to predict early sexual behaviour. Research on sexual content has not allowed for the social context of media use, which may affect selection and processing of content. This study investigated whether sexual media content and/or contextual factors (co-viewing, parental media restrictions) were associated with early sexual behaviour using 2251 14–15 year-olds from Scotland, UK. A third (n = 733) reported sexual intercourse. In multivariable analysis the likelihood of intercourse was lower with parental restriction of sexual media and same-sex peer co-viewing; but higher with mixed-sex peer co-viewing. Parental co-viewing, other parental restrictions on media and sexual film content exposure were not associated with intercourse. Findings suggest the context of media use may influence early sexual behaviour. Specific parental restrictions on sexual media may offer more protection against early sex than other restrictions or parental co-viewing. Further research is required to establish causal mechanisms. PMID:24215959

Female sexual maturation and reproduction after prepubertal exposure to estrogens and endocrine disrupting chemicals: a review of rodent and human data.

PubMed

Rasier, G; Toppari, J; Parent, A-S; Bourguignon, J-P

2006-07-25

Natural hormones and some synthetic chemicals spread into our surrounding environment share the capacity to interact with hormone action and metabolism. Exposure to such compounds can cause a variety of developmental and reproductive detrimental abnormalities in wildlife species and, potentially, in human. Many experimental and epidemiological data have reported that exposure of the developing fetus or neonate to environmentally relevant concentrations of some among these endocrine disrupters induces morphological, biochemical and/or physiological disorders in brain and reproductive organs, by interfering with the hormone actions. The impact of such exposures on the hypothalamic-pituitary-gonadal axis and subsequent sexual maturation is the subject of the present review. We will highlight epidemiological human studies and the effects of early exposure during gestational, perinatal or postnatal life in female rodents.

Age at sexual maturity, sex ratio, fecundity, and longevity of isolated headwater populations of westslope cutthroat trout

Treesearch

Christopher C. Downs; Robert G. White; Bradley B. Shepard

1997-01-01

We sampled 19 isolated headwater populations of westslope cutthroat trout Oncorhynchus clarki lewisi in Montana to provide estimates of fecundity, longevity, sex ratio, and age at sexual maturity. Fecundity was estimated for 31 fish collected from two streams in the upper Missouri River drainage. Females smaller than 149 mm fork length (FL) were generally immature and...

Factors associated with early resumption of sexual intercourse among postnatal women in Uganda.

PubMed

Alum, Alice C; Kizza, Irene B; Osingada, Charles P; Katende, Godfrey; Kaye, Dan K

2015-11-19

Despite being a key component to be addressed during postnatal period, sexuality has long been a subject of secrecy and taboo in Africa. Resumption of sexual intercourse after giving birth has been shown to reduce extramarital affairs and consequently reduce risk of sexually transmitted infections like HIV/AIDS. Consequences of early resumption of sexual intercourse include unwanted pregnancy, genital trauma and puerperal infection. The objective of the study was to assess prevalence and factors associated with early resumption of sexual intercourse among postnatal mothers attending postnatal clinic at a National referral Hospital in Uganda. A cross-sectional study that employed an interviewer-administered questionnaire was conducted among 374 women who delivered six months prior to conducting the study. The independent variables included socio-demographic characteristics of the participant, socio-demographic characteristics of the spouse, perceived cultural norms, medical history, mode of delivery, and postpartum complications. The dependent variable was timing of resumption of sexual intercourse after childbirth (before or after six weeks postpartum). Data were analysed using SPSS version 16.0. The study showed that 105 participants (21.6%) had resumed sexual intercourse before 6 weeks after childbirth. The participants' education level, occupation, and parity; education level of the spouse, age of baby and use of family planning were the factors associated with early resumption of sexual intercourse after child birth (before six weeks postpartum) (p < 0.05). Many women resumed sexual intercourse after six weeks. Women with high income, low parity, who ever-used contraception or had a spouse with high education level were more likely to have early resumption of sexual intercourse.

Understanding the Link Between Pubertal Timing in Girls and the Development of Depressive Symptoms: The Role of Sexual Harassment.

PubMed

Skoog, Therése; Bayram Özdemir, Sevgi; Stattin, Håkan

2016-02-01

The link between sexual maturation, or pubertal timing, in girls and adolescent depressive symptoms is well-documented, but the underlying processes remain unclear. We examined whether sexual harassment, which has previously been linked to both pubertal timing and depressive symptoms, mediates this link, using a two-wave longitudinal study including 454 girls in 7th (M age  = 13.42, SD = .53) and 8th grade (M age  = 14.42, SD = .55). Pubertal timing was linked to depressive symptoms in both age groups, and predicted an increase in depressive symptoms among the 7th graders. Sexual harassment significantly mediated the link between pubertal timing and depressive symptoms among the 7th, but not the 8th grade girls. Together, our findings suggest that one way to prevent depressive symptoms among early-maturing girls could be to address sexual harassment in preventive intervention in early adolescence.

Early sexual debut and associated factors among in-school adolescents in eight African countries.

PubMed

Peltzer, Karl

2010-08-01

This report examines early sexual debut (early sexual debut and alcohol, tobacco and other drug use, mental distress, physical activity, protective factors and socioeconomic status variables. A total of 27.3% had experienced sexual debut before age 15, 38.1% among boys and 15.8% among girls. Boys and girls with sexual debut at less than age 15 were more likely to report alcohol, tobacco and drug use, truancy, poor parental or guardian connectedness, sedentary behaviour, having been in a physical fight and seriously injured, while for girls, mental distress and poor economic status and for boys, bullied and poor parental or guardian supervision were associated with early coital debut. In multivariable analysis, early sexual debut was among boys associated with currently smoking (OR = 4.45, p = 0.002) and truancy (OR = 2.02, p = 0.007) and, among girls, associated with lower education (OR = 0.22, p = 0.004), ever drunk (OR = 3.94, p = 0.016), having no close friends (OR = 3.36, p = 0.014) and poor parental connectedness (OR = 2.43, p = 0.037). The study found a high prevalence of early sexual debut among 15-year-olds in eight African countries. Risk factors identified were consistent with problem behaviour theory in which early onset of adolescent sexual behaviour is shared with other problem behaviours. Prevention programmes should broaden sexual health promotion including problem behaviour such as substance use and mental distress for boys and girls in the preteen years, before sexual debut.

Masculinity in adolescent males' early romantic and sexual heterosexual relationships.

PubMed

Bell, David L; Rosenberger, Joshua G; Ott, Mary A

2015-05-01

There is a need to understand better the complex interrelationship between the adoption of masculinity during adolescence and the development of early romantic and sexual relationships. The purpose of this study was to describe features of adolescent masculinity and how it is expressed in the contexts of early to middle adolescent males' romantic and sexual relationships. Thirty-three 14- to 16-year-old males were recruited from an adolescent clinic serving a community with high sexually transmitted infection rates and were asked open-ended questions about their relationships-how they developed, progressed, and ended. Participants described a high degree of relationally oriented beliefs and behaviors related to romantic and sexual relationships, such as a desire for intimacy and trust. The males also described a more limited degree of conventionally masculine beliefs and behaviors. These beliefs and behaviors often coexisted or overlapped. Implications for the clinical care of similar groups of adolescents are described. © The Author(s) 2014.

Ecological influences of sexuality on early adolescent African American females.

PubMed

Aronowitz, Teri; Rennells, Rachel E; Todd, Erin

2006-01-01

African Americans make up the greater proportion of AIDS cases in adolescent girls but little is understood about the development of sexual risk behaviors during the early adolescent years. This article will explore ecological factors influencing adolescent sexual risk behaviors. In the focus groups, which were conducted using 28 African American mothers and their early adolescent daughters, 2 major themes emerged: exposure and support systems. Mothers described the impact community had on their daughters and how monitoring and support systems worked together to control exposure. The girls detailed the different ways they were impacted by the community. Attitudes the girls adopted from their exposures resulted in risk-taking behaviors or a determination to positively impact the community. Community was shown to be the context of the acquisition of sexual knowledge and attitudes. These findings support the development of interventions to address the impact of community on the participation of sexual risk behaviors.

Maturity-Associated Variation in Total and Depot-Specific Body Fat in Children and Adolescents

PubMed Central

Staiano, Amanda E.; Broyles, Stephanie T.; Gupta, Alok K.; Malina, Robert M.; Katzmarzyk, Peter T.

2014-01-01

Objectives This study considered the association between sexual maturation and adiposity in children and adolescents, and examined the contribution of sexual maturation to ethnic differences in total and depot-specific body fat. Methods The sample included 382 White and African American 5–18-year-olds. Body mass index (BMI), waist circumference (WC) and sexual maturity status (breast/genital and pubic hair stage) were assessed in a clinical setting. Total body fat (TBF) was measured by dual-energy X-ray absorptiometry and abdominal subcutaneous (SAT) and visceral adipose tissue (VAT) were measured by magnetic resonance imaging. Analysis of covariance adjusted for age was used to examine the association between sexual maturity status and adiposity, and linear regression adjusted for age was used to examine the influence of sexual maturation on ethnic differences in adiposity. Analysis of VAT also controlled for TBF. Significance was accepted at P<0.05. Results Breast/genital stage was significantly associated with BMI, WC, TBF, and SAT in girls of both ethnic groups and in White boys. Breast stage was associated with VAT. Stage of pubic hair was significantly associated with TBF and VAT in White girls only. In girls, sexual maturation attenuated the ethnic effects on BMI and WC, but the ethnic effect in VAT persisted. In boys, sexual maturation did not attenuate ethnic differences on VAT and did not predict WC or SAT. Sexual maturity status independently explained variance in adiposity in girls only. Conclusions Sexual maturity status is an important determinant of pediatric adiposity and attenuates ethnic differences in girls’ adiposity. PMID:23564417

Effect of temperature on pupa development and sexual maturity of laboratory Anastrepha obliqua adults.

PubMed

Telles-Romero, R; Toledo, J; Hernández, E; Quintero-Fong, J L; Cruz-López, L

2011-10-01

The effect of four temperatures (18, 20, 25 and 30°C) on pupa development and sexual maturity of Anastrepha obliqua adults was investigated under laboratory conditions. The results showed that the duration of the pupal stage decreased with an increase in temperature (29, 25, 13 and 12 days, respectively), and maintaining the pupae at 18°C and 20°C results in a low percentage of pupation, pupa weight loss and lesser flying ability. However, it significantly favored sexual behavior, a higher proportion of sexual calls and matings. While enhanced pupa development was observed at a temperature of 30°C, adults had low sexual efficiency, as well as a lower proportion of calls and matings. Gas chromatography-mass spectrometry (GC-MS) analysis of male volatiles showed that the amount of (Z,E)-α-farnesene did not vary among males from pupae reared at different temperatures; however, less (E,E)-α-farnesene was emitted by males obtain from pupa reared at 30°C. Male flies kept at 30°C during their larval stage had more (Z)-3-nonenol and, also, an unknown compound was detected. The fecundity of the females was higher at low temperatures. Regarding fertility, no significant differences were found between temperatures. The optimal temperature on pupa development was 25°C when males displayed ideal attributes for rearing purposes.

Are female orphans at risk for early marriage, early sexual debut, and teen pregnancy? Evidence from sub-Saharan Africa.

PubMed

Palermo, Tia; Peterman, Amber

2009-06-01

Female orphans are widely cited as being at risk for early marriage, early childbearing, and risky sexual behavior; however, to date no studies have examined these linkages using population-level data across multiple countries. This study draws from recent Demographic and Health Surveys from ten sub-Saharan African countries to examine the relationship between orphanhood status and measures of early marriage, early sexual debut, and teen pregnancy among adolescent girls aged 15 to 17. Results indicate that, overall, little association is found between orphanhood and early marriage or teen pregnancy, whereas evidence from seven countries supports associations between orphanhood and early sexual debut. Findings are sensitive to the use of multivariate models, type of orphan, and country setting. Orphanhood status alone may not be a sufficient targeting mechanism for addressing these outcomes in many countries; a broader, multidimensional targeting scheme including orphan type, schooling, and poverty measures would be more robust in identifying and aiding young women at risk.

Histological assessment of organs in sexually mature and post-spawning steelhead trout and insights into iteroparity

USGS Publications Warehouse

Penney, Zachary L.; Moffitt, Christine M.

2014-01-01

Steelhead trout (Oncorhynchus mykiss) are anadromous and iteroparous, but repeat-spawning rates are generally low. Like other anadromous salmonids, steelhead trout fast during freshwater spawning migrations, but little is known about the changes that occur in vital organs and tissues. We hypothesized that fish capable of repeat-spawning would not undergo the same irreversible degeneration and cellular necrosis documented in semelparous salmon. Using Snake River steelhead trout as a model we used histological analysis to assess the cellular architecture in the pyloric stomach, ovary, liver, and spleen in sexually mature and kelt steelhead trout. We observed 38 % of emigrating kelts with food or fecal material in the gastrointestinal tract. Evidence of feeding was more likely in good condition kelts, and feeding was associated with a significant renewal of villi in the pyloric stomach. No vitellogenic oocytes were observed in sections of kelt ovaries, but perinucleolar and early/late stage cortical alveolus oocytes were present suggesting iteroparity was possible. We documented a negative correlation between the quantity of perinucleolar oocytes in ovarian tissues and fork length of kelts suggesting that larger steelhead trout may invest more into a single spawning event. Liver and spleen tissues of both mature and kelt steelhead trout had minimal cellular necroses. Our findings indicate that the physiological processes causing rapid senescence and death in semelparous salmon are not evident in steelhead trout, and recovery begins in fresh water. Future management efforts to increase iteroparity in steelhead trout and Atlantic salmon must consider the physiological processes that influence post-spawning recovery.

Can Sex Education Delay Early Sexual Debut?

ERIC Educational Resources Information Center

Erkut, Sumru; Grossman, Jennifer M.; Frye, Alice A.; Ceder, Ineke; Charmaraman, Linda; Tracy, Allison J.

2013-01-01

In this study, we examine whether a nine-lesson sex education intervention, "Get Real: Comprehensive Sex Education That Works," implemented in sixth grade, can reduce the number of adolescents who might otherwise become "early starters" of sexual activity (defined as heterosexual intercourse) by seventh grade. Participants were…

Energy intake functions and energy budgets of ectotherms and endotherms derived from their ontogenetic growth in body mass and timing of sexual maturation.

PubMed

Werner, Jan; Sfakianakis, Nikolaos; Rendall, Alan D; Griebeler, Eva Maria

2018-05-07

Ectothermic and endothermic vertebrates differ not only in their source of body temperature (environment vs. metabolism), but also in growth patterns, in timing of sexual maturation within life, and energy intake functions. Here, we present a mathematical model applicable to ectothermic and endothermic vertebrates. It is designed to test whether differences in the timing of sexual maturation within an animal's life (age at which sexual maturity is reached vs. longevity) together with its ontogenetic gain in body mass (growth curve) can predict the energy intake throughout the animal's life (food intake curve) and can explain differences in energy partitioning (between growth, reproduction, heat production and maintenance, with the latter subsuming any other additional task requiring energy) between ectothermic and endothermic vertebrates. With our model we calculated from the growth curves and ages at which species reached sexual maturity energy intake functions and energy partitioning for five ectothermic and seven endothermic vertebrate species. We show that our model produces energy intake patterns and distributions as observed in ectothermic and endothermic species. Our results comply consistently with some empirical studies that in endothermic species, like birds and mammals, energy is used for heat production instead of growth, and with a hypothesis on the evolution of endothermy in amniotes published by us before. Our model offers an explanation on known differences in absolute energy intake between ectothermic fish and reptiles and endothermic birds and mammals. From a mathematical perspective, the model comes in two equivalent formulations, a differential and an integral one. It is derived from a discrete level approach, and it is shown to be well-posed and to attain a unique solution for (almost) every parameter set. Numerically, the integral formulation of the model is considered as an inverse problem with unknown parameters that are estimated using a

Adolescent's sexual problems in Korea.

PubMed

Kang, B S

1990-07-01

This article discusses primary contributors of sexual problems among Korean adolescents. As a result of improved nutrition, physical maturity is occurring at an earlier age in Korean youths. On the other hand, marital age has increased; the average age for males to marry is 27.3 years and 24.1 years in females. Hence, these factors extend the time frame between onset of sexual maturity and marriage. Enrollment in schools has risen; middle school registration has increased from 74.2% in 1975 to 99.7% in 1985 and from 43.6% to 78.3% in high schools. Increased enrollment has also been observed at the university level which may promote prolonged educational periods; this focus on education may reduce sexual interest among students. Improved employment opportunities may also influence sexual behavior among adolescents; urban migration can encourage casual relationships. Changes in family structure and sexual morals has promoted liberal attitudes regarding sexual practices. Increased exposure to mass media has affected adolescent sexual problems; 99.1% of the households in 1985 possessed televisions. These sexual problems include onset of sexual intercourse at an earlier age, unwanted pregnancies, increased induced abortions, and early childbirth. Overall, sexual activity in females has risen from 3.6% in 1965 to 14.5% in 1981 and from 18.5% in 1971 for males to 27.7% in 1981. Pre-marital pregnancy rates have continually increased since 1950; this has resulted in a rise of unwed mothers' consultations which reflects adolescent childbirths. Sex-related crime have also increased; rape ranks 3rd in crimes committed by Korean youth. Sex education and family planning should be provided for adolescents. Furthermore, counseling services should be available to youth regarding unwanted pregnancies, sexually transmitted diseases, and contraception. The Planned Parenthood Federation of Korea provides youth sex telephone services in which adolescents can acquire information on

Sex-Specific Pathways to Early Puberty, Sexual Debut, and Sexual Risk Taking: Tests of an Integrated Evolutionary-Developmental Model

ERIC Educational Resources Information Center

James, Jenee; Ellis, Bruce J.; Schlomer, Gabriel L.; Garber, Judy

2012-01-01

The current study tested sex-specific pathways to early puberty, sexual debut, and sexual risk taking, as specified by an integrated evolutionary-developmental model of adolescent sexual development and behavior. In a prospective study of 238 adolescents (n = 129 girls and n = 109 boys) followed from approximately 12-18 years of age, we tested for…

Family Homework and School-Based Sex Education: Delaying Early Adolescents' Sexual Behavior

ERIC Educational Resources Information Center

Grossman, Jennifer M.; Frye, Alice; Charmaraman, Linda; Erkut, Sumru

2013-01-01

Background: Early sexual activity can undermine adolescents' future school success and health outcomes. The purpose of this study was to assess the role of a family homework component of a comprehensive sex education intervention in delaying sexual initiation for early adolescents and to explore what social and contextual factors prevent…

A Theater-Based Approach to Primary Prevention of Sexual Behavior for Early Adolescents

ERIC Educational Resources Information Center

Lieberman, Lisa D.; Berlin, Cydelle; Palen, Lori-Ann; Ashley, Olivia Silber

2012-01-01

Early adolescence is a crucial period for preventing teen pregnancy and sexually transmitted infections. This study evaluated STAR LO, a theater-based intervention designed to affect antecedents of sexual activity among urban early adolescents (N = 1,143). Public elementary/middle schools received the intervention or served as a wait-listed…

Maturational differences in physical self- perceptions and the relationship with physical activity in early adolescent girls.

PubMed

Niven, Alisa G; Fawkner, Samantha G; Knowles, Anne-Marie; Stephenson, Claire

2007-11-01

This cross-sectional study examined the relationship between physical self-perceptions (PSPs), maturation, and physical activity and compared the strength of the relationships of biological and chronological age with PSPs in early adolescent girls (N = 208; mean age = 11.83 +/- 0.39 years). Participants completed the Physical Activity Questionnaire for Older Children, the Children's Physical Self-Perception Profile, and the Pubertal Development Scale. Results indicated that PSPs were significantly and moderately correlated with physical activity. There were no differences in physical activity between maturation stages. Girls who were in the early stages of maturation had significantly more positive perceptions of body attractiveness and physical self-worth than girls in the mid stages of maturation. There was no evidence of a relationship between PSPs and chronological age. This study provided further support for the relationship between PSPs and physical activity and the relationship between maturation and aspects of PSPs. In this age group, maturation does not appear to be related to physical activity or the PSPs most strongly influential on physical activity behavior.

Child Abuse, Early Maladaptive Schemas, and Risky Sexual Behavior in College Women

ERIC Educational Resources Information Center

Roemmele, Melissa; Messman-Moore, Terri L.

2011-01-01

Previous research suggests that individuals abused as children are more likely to engage in risky sexual behavior during adulthood. The present study examined early maladaptive schemas as mediators of the child abuse-risky sexual behavior relationship among 653 college women. Self-report surveys assessed three forms of child abuse: Sexual,…

The effects of ozonation on select waterborne steroid hormones in recirculation aquaculture systems containing sexually mature Atlantic salmon Salmo salar

USDA-ARS?s Scientific Manuscript database

A controlled 3-month study was conducted in 6 replicated water recirculation aquaculture systems (RAS) containing a mixture of sexually mature and immature Atlantic salmon Salmo salar to determine whether water ozonation is associated with a reduction in waterborne hormones. Post-smolt Atlantic salm...

A Mixed-Methods Inquiry into the Intimate Practices of Partnered Mature Students and Influences on Relationship, Sexual, and School Satisfaction

ERIC Educational Resources Information Center

van Rhijn, Tricia M.; Murray, Sarah H.; Mizzi, Robert C.

2015-01-01

Through the use of mixed qualitative and quantitative methods, the current study explored the impact of postsecondary study on the intimate relationships and school experiences of partnered mature students. Quantitative regression analyses indicated that parental status, family support, partner support, and sexual desire significantly predicted…

A role for leptin in sexual maturation and puberty?

PubMed

Kiess, W; Reich, A; Meyer, K; Glasow, A; Deutscher, J; Klammt, J; Yang, Y; Müller, G; Kratzsch, J

1999-01-01

Leptin, the ob gene product, is involved in the regulation of body weight in rodents, primates and humans. It provides a molecular basis for the lipostatic theory of the regulation of energy balance. White adipose tissue and placenta are the main sites of leptin synthesis. There is also evidence of ob gene expression in brown fat. Leptin seems to play a key role in the control of body fat stores by coordinated regulation of feeding behaviour, metabolic rate, autonomic nervous system regulation and body energy balance. Apart from the function of leptin in the central nervous system on the regulation of energy balance, it may well be one of the hormonal factors that signal to the brain the body's readiness for sexual maturation and reproduction. During late pregnancy and at birth when maternal fat stores have been developed, leptin levels are high. During these developmental stages leptin could be a messenger molecule signalling the adequacy of the fat stores for reproduction and maintenance of pregnancy. At later stages of gestation leptin could signal the expansion of fat stores in order to prepare the expectant mother for the energy requirements of full-term gestation, labour and lactation. Leptin serum concentrations change during pubertal development in rodents, primates and humans. In girls, leptin serum concentrations increase dramatically as pubertal development proceeds. The pubertal rise in leptin levels parallels the increase in body fat mass. In contrast, leptin levels increase shortly before and during the early stages of puberty in boys and decline thereafter. Testosterone has been found to suppress leptin synthesis by adipocytes both in vivo and in vitro. The decline of leptin levels in late puberty in boys accompanies increased androgen production during that time and most likely reflects suppression of leptin by testosterone and a decrease in fat mass and relative increase in muscle mass during late puberty in males. This overview focuses on those

Long-Term Consequences of Early Sexual Initiation on Young Adult Health: A Causal Inference Approach

ERIC Educational Resources Information Center

Kugler, Kari C.; Vasilenko, Sara A.; Butera, Nicole M.; Coffman, Donna L.

2017-01-01

Although early sexual initiation has been linked to negative outcomes, it is unknown whether these effects are causal. In this study, we use propensity score methods to estimate the causal effect of early sexual initiation on young adult sexual risk behaviors and health outcomes using data from the National Longitudinal Study of Adolescent to…

NIEHS/EPA CEHCs: Perinatal Exposures, Epigenetics, Child Obesity and Sexual Maturation - University of Michigan

EPA Pesticide Factsheets

Scientists are seeking to understand how early exposure to chemicals such as lead, bisphenol A (BPA), and phthalates affects growth and sexual development during childhood and adolescence and the risk for diseases in adulthood.

The role of pregnancy awareness on female sexual function in early gestation.

PubMed

Corbacioglu, Aytul; Bakir, Vuslat Lale; Akbayir, Ozgur; Cilesiz Goksedef, Behiye Pinar; Akca, Aysu

2012-07-01

Female sexual function is negatively influenced by pregnancy due to the physical and emotional changes. Although the most significant effect is seen in the third trimester of pregnancy, a considerable decrease in the frequency of intercourse and sexual desire in the first trimester has also been shown. To investigate the factors that affect sexuality in early pregnancy and the impact of awareness of pregnancy on female sexual function in the first trimester of pregnancy using two self-reported questionnaires. In this cross-sectional study, 130 healthy, married pregnant women who were admitted to the gynecology clinic between the 4th and 10th week of gestation were asked to complete a self-administered questionnaire and the female sexual function index (FSFI). The factors associated with FSFI score and monthly sexual activity frequency in the first trimester, as well as the differences in sexual activity frequency and FSFI scores between the women who were previously aware of their pregnancy and those who were yet unaware of their pregnancy. Women who were unaware of their pregnancy had significantly higher coitus frequency in comparison with the aware group (P = 0.002). Total FSFI score was 21.99 ± 8.13 in the aware group and 24.66 ± 3.76 in the unaware group (P = 0.02). None of the obstetric and sociodemographic variables had an influence on desire and pain scores. Arousal, lubrication, and satisfaction scores were adversely affected by awareness of pregnancy. Orgasm scores were influenced negatively by awareness and positively by love marriage; however, in multivariate linear regression analysis none of these were defined as independent factor for orgasm scores. Overall FSFI scores and monthly frequency of sexual activity were only affected by awareness. The results of this study suggest that in early gestation, awareness of pregnancy is associated with lower female sexual function. Furthermore, obstetric and sociodemographic factors seem to be

Macro-level age norms for the timing of sexual initiation and adolescents' early sexual initiation in 17 European countries.

PubMed

Madkour, Aubrey Spriggs; de Looze, Margaretha; Ma, Ping; Halpern, Carolyn Tucker; Farhat, Tilda; Ter Bogt, Tom F M; Ehlinger, Virginie; Nic Gabhainn, Saoirse; Currie, Candace; Godeau, Emmanuelle

2014-07-01

To examine the relationship between country-level age norms for sexual initiation timing and early sexual initiation (ESI) among adolescent boys and girls. Nationally representative data from 17 countries that participated in the 2006/2007 European Social Survey (ESS-3, n = 33,092) and the 2005/2006 Health Behaviour in School-Aged Children Study (HBSC, n = 27,702) were analyzed. Age norms were measured as the average country-level response to an item asking the age at which ESS respondents believed someone is too young to have sexual intercourse. HBSC respondents (aged 14-16 years) self-reported age at sexual initiation, which we defined as early (<15 years) or not early (≥15 years or no initiation). Control variables included age, family affluence, perceived socioeconomic status, family living arrangement, substance use, school attachment, and country-level legal age of consent. Multivariable three-level logistic models with random intercepts were run separately by sex. In multivariable analyses, higher overall age norms were associated with reduced likelihood of ESI among girls (AOR .60, 95% CI .45-.79); associations with ESI were stronger for parent cohort (ages 31-65 years) norms (AOR .37, 95% CI .23-.58) than for peer cohort (ages 15-20 years) norms (AOR .60, 95% CI .49-.74). For boys, overall norms were also significantly negatively associated with ESI (AOR .68, 95% CI .46-.99), as were parent cohort norms (AOR .66, 95% CI .45-.96). Peer cohort norms were not significantly related to boys' ESI. Macrolevel cultural norms may impact adolescents' sexual initiation timing. Research exploring the sexual health outcomes of early initiators in countries with contrasting age norms is warranted. Copyright © 2014 Society for Adolescent Health and Medicine. All rights reserved.

Effects of Prenatal Cocaine Exposure on Early Sexual Behavior: Gender Difference in Externalizing Behavior as a Mediator

PubMed Central

Min, Meeyoung O.; Minnes, Sonia; Lang, Adelaide; Yoon, Susan; Singer, Lynn T.

2015-01-01

Background Prenatal cocaine exposure (PCE) is associated with increased risk for externalizing behavior problems; childhood externalizing behavior problems are linked with subsequent early sexual behavior. The present study examined the effects of PCE on early sexual initiation (sexual intercourse prior to age 15) and whether externalizing behavior in preadolescence mediated the relationship. Methods Three hundred fifty-four (180 PCE and 174 non-cocaine exposed; 192 girls, 142 boys), primarily African-American, low socioeconomic status, 15-year old adolescents participated in a prospective longitudinal study. Adolescents’ sexual behavior was assessed at 15 years using the Youth Risk Behavior Surveillance System. Externalizing behavior was assessed at 12 years using the Youth Self-Report. Results Logistic regression models indicated that adolescents with PCE (n=69, 38%) were 2.2 times more likely (95% CI= 1.2 – 4.1, p < .01) to engage in early sexual intercourse than non-exposed peers (n=49, 28%) controlling for covariates. This relationship was fully mediated by self-reported externalizing behavior in girls but not in boys, suggesting childhood externalizing behavior as a gender moderated mediator. Blood lead level during preschool years was also related to a greater likelihood of early sexual intercourse (OR=2.6, 95% CI=1.4 – 4.7, p < .002). Greater parental monitoring decreased the likelihood of early sexual intercourse, while violence exposure increased the risk. Conclusions PCE is related to early sexual intercourse, and externalizing behavior problems mediate PCE effects in female adolescents. Interventions targeting externalizing behavior may reduce early sexual initiation and thereby reduce HIV risk behaviors and early, unplanned pregnancy in girls with PCE. PMID:26088698

Effects of prenatal cocaine exposure on early sexual behavior: Gender difference in externalizing behavior as a mediator.

PubMed

Min, Meeyoung O; Minnes, Sonia; Lang, Adelaide; Yoon, Susan; Singer, Lynn T

2015-08-01

Prenatal cocaine exposure (PCE) is associated with increased risk for externalizing behavior problems; childhood externalizing behavior problems are linked with subsequent early sexual behavior. The present study examined the effects of PCE on early sexual initiation (sexual intercourse prior to age 15) and whether externalizing behavior in preadolescence mediated the relationship. Three hundred fifty-four (180 PCE and 174 non-cocaine exposed; 192 girls, 142 boys), primarily African-American, low socioeconomic status, 15-year-old adolescents participated in a prospective longitudinal study. Adolescents' sexual behavior was assessed at 15 years using the Youth Risk Behavior Surveillance System. Externalizing behavior was assessed at 12 years using the Youth Self-Report. Logistic regression models indicated that adolescents with PCE (n=69, 38%) were 2.2 times more likely (95% CI=1.2-4.1, p<.01) to engage in early sexual intercourse than non-exposed peers (n=49, 28%) controlling for covariates. This relationship was fully mediated by self-reported externalizing behavior in girls but not in boys, suggesting childhood externalizing behavior as a gender moderated mediator. Blood lead level during preschool years was also related to a greater likelihood of early sexual intercourse (OR=2.6, 95% CI=1.4-4.7, p<.002). Greater parental monitoring decreased the likelihood of early sexual intercourse, while violence exposure increased the risk. PCE is related to early sexual intercourse, and externalizing behavior problems mediate PCE effects in female adolescents. Interventions targeting externalizing behavior may reduce early sexual initiation and thereby reduce HIV risk behaviors and early, unplanned pregnancy in girls with PCE. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

CD101, a Novel Echinocandin, Possesses Potent Antibiofilm Activity against Early and Mature Candida albicans Biofilms.

PubMed

Chandra, Jyotsna; Ghannoum, Mahmoud A

2018-02-01

Currently available echinocandins are generally effective against Candida biofilms, but the recent emergence of resistance has underscored the importance of developing new antifungal agents that are effective against biofilms. CD101 is a long-acting novel echinocandin with distinctive pharmacokinetic properties and improved stability and safety relative to other drugs in the same class. CD101 is currently being evaluated as a once-weekly intravenous (i.v.) infusion for the treatment of candidemia and invasive candidiasis. In this study, we determined (i) the effect of CD101 against early and mature phase biofilms formed by C. albicans in vitro and (ii) the temporal effect of CD101 on the formation of biofilms using time-lapse microscopy (TLM). Early- or mature-phase biofilms were formed on silicone elastomer discs and were exposed to the test compounds for 24 h and quantified by measuring their metabolic activity. Separate batches were observed under a confocal microscope or used to capture TLM images from 0 to 16 h. Measurements of their metabolic activity showed that CD101 (0.25 or 1 μg/ml) significantly prevented adhesion-phase cells from developing into mature biofilms ( P = 0.0062 or 0.0064, respectively) and eradicated preformed mature biofilms ( P = 0.04 or 0.01, respectively) compared to those of untreated controls. Confocal microscopy showed significant reductions in biofilm thicknesses for both early and mature phases ( P < 0.05). TLM showed that CD101 stopped the growth of adhesion- and early-phase biofilms within minutes. CD101-treated hyphae failed to grow into mature biofilms. These results suggest that CD101 may be effective in the prevention and treatment of biofilm-associated nosocomial infections. Copyright © 2018 Chandra and Ghannoum.

Exploring Work and Development Options to Reduce Early Labour Force Exit of Mature Aged Australians

ERIC Educational Resources Information Center

Pillay, Hitendra; Kelly, Kathy; Tones, Megan

2008-01-01

Early labour force exit is a significant challenge associated with the ageing workforce in Australia and many other developed countries. A reduction and increased flexibility of work hours has been suggested to improve labour force participation of the mature aged cohort. However, little is known about mature aged workers' aspirations for…

Sexual abuse in childhood and adolescence and the risk of early pregnancy among women ages 18-22.

PubMed

Young, Maria-Elena D; Deardorff, Julianna; Ozer, Emily; Lahiff, Maureen

2011-09-01

This clinic- and community-based study of young women investigated the relationship between previous sexual abuse and early pregnancy, examining the effect of the developmental period in which sexual abuse occurred and type of sexual abuse, while also providing methodological advances in the assessment of distinctive sexual abuse and its sequelae. Secondary data analysis using Cox proportional hazards models was conducted to determine the association between sexual abuse in childhood, in adolescence, or both, and risk of early pregnancy among 1,790 young women. In addition, this study examined the type of sexual abuse that occurred during each period. As compared with women with no history of sexual abuse, women who experienced sexual abuse only in childhood had a 20% greater hazard of pregnancy; women who experienced sexual abuse only in adolescence had a 30% greater hazard of pregnancy; and women who experienced sexual abuse in both childhood and adolescence had an 80% greater hazard of pregnancy. Across these periods, attempted rape and rape were associated with an increased hazard of pregnancy. The association between sexual abuse and pregnancy was mediated by age at first intercourse and moderated by a woman's education level. This study provides evidence that both the developmental timing and the type of sexual abuse contributes to an increased risk for early pregnancy. The study findings indicate that sexual abuse leads to an earlier age of first sexual intercourse, which in turn increases the likelihood of an early pregnancy. Women with higher educational attainment are less likely to experience early pregnancy as a result of abuse. Copyright © 2011 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Do summer temperatures trigger spring maturation in pacific lamprey, Entosphenus tridentatus?

USGS Publications Warehouse

Clemens, B.J.; Van De Wetering, S.; Kaufman, J.; Holt, R.A.; Schreck, C.B.

2009-01-01

Pacific lamprey, Entosphenus tridentatus, return to streams and use somatic energy to fuel maturation. Body size decreases, the lamprey mature, spawn, and then die. We predicted that warm, summer temperatures (>20 ??C) would accentuate shrinkage in body size, and expedite sexual maturation and subsequent death. We compared fish reared in the laboratory at diel fluctuating temperatures of 20-24 ??C (mean = 21.8 ??C) with fish reared at cooler temperatures (13.6 ??C). The results confirmed our predictions. Lamprey from the warm water group showed significantly greater proportional decreases in body weight following the summer temperature treatments than fish from the cool water group. A greater proportion of warm water fish sexually matured (100%) and died (97%) the following spring than cool water fish (53% sexually mature, 61% died). Females tended to mature and die earlier than males, most obviously in the warm water group. ?? 2009 John Wiley & Sons A/S.

[Reproductive pattern and mean size of sexual maturity of female lobsters Panulirus gracilis (Decapoda: Palinuridae) in Playa Lagarto, Guanacaste, Costa Rica].

PubMed

Naranjo Madrigal, Helven

2012-12-01

The lobster P. gracilis is important as a fishery resource and also contributes to food security of fishers in coastal communities in the North Pacific of Costa Rica. Due to the importance of updating knowledge related to the reproductive pattern of this species, we analyzed 357 specimens of female lobsters caught by the fishing methods of "hookah" and lung diving, from November 2007 to October 2008 in Playa Lagarto. Furthermore, we examined the size composition by depth; monthly pattern of reproductive activity (RAI) associated with the relative increase in sea surface temperature, and also the mean size at maturity using Generalized Linear Models. Four physiological states of sexual maturity showed that females with no signs of mating or sexual maturity have a minimum mean size of 62.3mm of cephalothorax length (CL). There are characteristics of functional maturity from very small sizes ranging from 30 to 50mm CL, being the smallest berried female reported for this specie of 35.8mm CL and the highest percentage of mature females between 70 and 80mm CL. Percentages of RAI remained above 50% during the year except October and January. In addition, it observed an increase in the RAI that started from April and continued until August associated with a relative increase in temperature on March, although the correlation was not significant (r2=0.49, p>0.05). It is possible that the low mean size at maturity (70.2mm LC) for P. gracilis in this region is related to the fishing activity. It recommends the establishment of a ban in the region of at least five months (April-August) in order to protect the reproductive seasonality of the species and to promote a recruitment increase in the fishing areas.

The maturation of cortical sleep rhythms and networks over early development

PubMed Central

Chu, CJ; Leahy, J; Pathmanathan, J; Kramer, MA; Cash, SS

2014-01-01

Objective Although neuronal activity drives all aspects of cortical development, how human brain rhythms spontaneously mature remains an active area of research. We sought to systematically evaluate the emergence of human brain rhythms and functional cortical networks over early development. Methods We examined cortical rhythms and coupling patterns from birth through adolescence in a large cohort of healthy children (n=384) using scalp electroencephalogram (EEG) in the sleep state. Results We found that the emergence of brain rhythms follows a stereotyped sequence over early development. In general, higher frequencies increase in prominence with striking regional specificity throughout development. The coordination of these rhythmic activities across brain regions follows a general pattern of maturation in which broadly distributed networks of low-frequency oscillations increase in density while networks of high frequency oscillations become sparser and more highly clustered. Conclusion Our results indicate that a predictable program directs the development of key rhythmic components and physiological brain networks over early development. Significance This work expands our knowledge of normal cortical development. The stereotyped neurophysiological processes observed at the level of rhythms and networks may provide a scaffolding to support critical periods of cognitive growth. Furthermore, these conserved patterns could provide a sensitive biomarker for cortical health across development. PMID:24418219

The Relationship Between Early Sexual Debut and Psychosocial Outcomes: A Longitudinal Study of Dutch Adolescents

PubMed Central

Sandfort, Theo; Reitz, Ellen; Bos, Henny; Dekovic, Maja

2010-01-01

In a longitudinal dataset of 470 Dutch adolescents, the current study examined the ways in which early sexual initiation was related to subsequent attachment, self-perception, internalizing problems, and externalizing problems. For male adolescents, analyses revealed general attachment to mother and externalizing problems at Wave 1 to predict to early transition at Wave 2. However, there was no differential change in these psychosocial factors over time for early initiators of sexual intercourse and their non-initiating peers. For female adolescents, the model including psychosocial factors at Wave 1 did not predict to sexual initiation at Wave 2. However, univariate repeated measures analyses revealed early initiators to have significantly larger increases in self-concept and externalizing problems than their non-initiating female peers. While the difference between female early initiators and non-initiators were statistically significant, the mean levels of problem behaviors were very low. The findings suggest that, contrary to previous research, early sexual initiation does not seem to be clustered with problem behaviors for this sample of Dutch adolescents. PMID:20119696

Sex and sexual orientation disparities in adverse childhood experiences and early age at sexual debut in the United States: Results from a nationally representative sample☆

PubMed Central

Brown, Monique J.; Masho, Saba W.; Perera, Robert A.; Mezuk, Briana; Cohen, Steven A.

2015-01-01

Adverse childhood experiences (ACEs) have been linked to early sexual debut, which has been found to be associated with multiple adverse health outcomes. Sexual minorities and men tend to have earlier sexual debut compared to heterosexual populations and women, respectively. However, studies examining the association between ACEs and early sexual debut among men and sexual minorities are lacking. The aim of this study was to examine the sex and sexual orientation disparities in the association between ACEs and age at sexual debut. Data were obtained from Wave 2 of the National Epidemiologic Survey on Alcohol and Related Conditions. Logistic and linear regression model were used to obtain crude and adjusted estimates and 95% confidence intervals adjusting for age, race/ethnicity, income, education, insurance and marital status for the association between ACEs (neglect, physical/psychological abuse, sexual abuse, parental violence, and parental incarceration and psychopathology) and early sexual debut. Analyses were stratified by sex and sexual orientation. Larger effect estimates depicting the association between ACEs and sexual debut were seen for women compared to men, and among sexual minorities, particularly among men who have sex with men (MSM) and women who have sex with women (WSW), compared to heterosexuals. Sexual health education programs with a focus on delaying sexual debut among children and adolescents should also consider addressing ACEs, such as neglect, physical, psychological and sexual abuse, witnessing parental violence, and parental incarceration and psychopathology. Public health practitioners, researchers and sexual health education curriculum coordinators should consider these differences by sex and sexual orientation when designing these programs. PMID:25804435

[Determinants of early sexual initiation in the Pelotas birth cohort from 1982 to 2004-5, Southern Brazil].

PubMed

Gonçalves, Helen; Béhague, Dominique P; Gigante, Denise P; Minten, Gicele C; Horta, Bernardo L; Victora, Cesar G; Barros, Fernando C

2008-12-01

To analyze social determinants of early sexual initiation among young adults from a birth cohort. Individuals from the 1982 birth cohort (N=4,297) were interviewed in 2004-5, city of Pelotas, Southern Brazil. Early sexual initiation (<13 years of age) was the outcome. Descriptive and stratified analyses were performed according to sex. Variables analyzed were family income in 1982, ethnicity, young adult's level of education and change in income (between 1982 and 2004-5). Ethnographic data were used to complement result analysis. Prevalence of early sexual initiation was higher among black and mixed men, and those with low level of education and low family income in 1982 and 2004-5. More traditional male sexual role requirements, such as virility and sexual initiative, showed more repercussion and adherence from an early age among men. Young family women with higher income and level of education tended to delay their sexual initiation. Imposition of traditional values was found to influence early sexual initiation among men and women with lower level of education and income. Results found re-established the economic factor as a determinant of behavior or uses of sexuality for both sexes. To focus on political efforts that help the economically disadvantaged to have opportunities and egalitarian future perspectives is an important strategy for health outcomes.

Why does early sexual intercourse predict subsequent maladjustment? Exploring potential familial confounds.

PubMed

Donahue, Kelly L; Lichtenstein, Paul; Långström, Niklas; D'Onofrio, Brian M

2013-02-01

Previous studies have found an association between early age at first sexual intercourse and subsequent psychosocial maladjustment. Using a quasi-experimental approach, we examined the extent to which this observed association may be due to familial confounds not explored in prior research. Using a population-based cohort of Swedish adult twins (ages 19-47; N = 12,126), we examined the nature of the association between early sexual intercourse (i.e., first intercourse occurring before age 16) and various outcomes reflecting psychosocial health, including substance use, depression, criminal convictions, and adolescent childbearing. We used two methods--discordant-twin analyses and bivariate twin modeling--to estimate the extent to which genetic and environmental confounds explained observed associations. Individuals who engaged in early intercourse were at greater risk for most of the adverse psychosocial health outcomes measured in this study. However, twin pairs discordant for engaging in early intercourse did not differ significantly in their risk for psychosocial maladjustment. Our results indicated that early age at first sexual intercourse and subsequent psychosocial maladjustment may be associated because of familial factors shared by twins. Early intercourse may be associated with poor psychosocial health largely due to shared familial influences rather than through a direct causal connection. Therefore, effective and efficient interventions should address other risk factors common to early intercourse and poor psychosocial health.

Cognitive structures in women with sexual dysfunction: the role of early maladaptive schemas.

PubMed

Oliveira, Cátia; Nobre, Pedro J

2013-07-01

Cognitive schemas are often related to psychological problems. However, the role of these structures within sexual problems is not yet well established. The aim of this study was to evaluate the presence and importance of early maladaptive schemas on women's sexual functioning and cognitive schemas activated in response to negative sexual events. A total of 228 women participated in the study: a control sample of 167 women without sexual problems, a subclinical sample of 37 women with low sexual functioning, and a clinical sample of 24 women with sexual dysfunction. Participants completed several self-reported measures: the Schema Questionnaire, the Questionnaire of Cognitive Schema Activation in Sexual Context, the Brief Symptom Inventory, the Beck Depression Inventory, and the Female Sexual Function Index. Findings indicated that women with sexual dysfunction presented significantly more early maladaptive schemas from the Impaired Autonomy and Performance domain, particularly failure (P < 0.001, η(2) = 0.08), dependence/incompetence (P < 0.05, η(2) = 0.03), and vulnerability to danger (P < 0.05, η(2) = 0.04). Additionally, in response to negative sexual events, women with sexual dysfunction presented significantly higher scores on incompetence (P < 0.001, η(2) = 0.16), self-depreciation (P < 0.01, η(2) = 0.05), and difference/loneliness (P < 0.01, η(2) = 0.05) schemas. Results supported differences between women with and without sexual problems regarding cognitive factors. This may have implications for the knowledge, assessment, and treatment of sexual dysfunction in women. © 2012 International Society for Sexual Medicine.

Early Puberty in African-American Girls: Nutrition Past and Present.

ERIC Educational Resources Information Center

Talpade, Medha; Talpade, Salil

2001-01-01

Early sexual maturation is associated with many high-risk behaviors and a prediction was made that food consumption may contribute to early onset of puberty. A comparison was made between the eating habits of several generations of African-American women. Girls today were found to consume more calcium, grains, and meat then older women did in…

Maturational and Non-Maturational Factors in Heritage Language Acquisition

ERIC Educational Resources Information Center

Moon, Ji Hye

2012-01-01

This dissertation aims to understand the maturational and non-maturational aspects of early bilingualism and language attrition in heritage speakers who have acquired their L1 incompletely in childhood. The study highlights the influential role of age and input dynamics in early L1 development, where the timing of reduction in L1 input and the…

[Fitness of sexual reproduction of Toona ciliata var. pubescens natural populations and their sexual reproduction and regeneration].

PubMed

Huang, Hong Lan; Zhang, Lu; Jia, Li Ming; Liang, Yue-Long; Cai, Jun Huo

2018-04-01

To examine the reproduction fitness coefficients and individual-level fitness of Toona ciliata var. pubescens, their sexual reproduction and natural regeneration were investigated during 2006-2016, with four natural populations in Jiulianshan National Reserve as test objects. The results showed that there were only 2-10 trees for the natural populations of T. ciliata var. pubescens with a small initial number of fruiting plants (3-9 trees), which were from the initial fruiting plants or their first/second generation. The sexual reproduction of these isolated populations were significantly different, and their seed production capacities tended to decline over time. With the maturing of communities, soil seed banks and seed germinations were extremely poor, and the number of trees that could be growing to mature stage was nearly zero. The optimum maturity age of T. ciliata var. pubescens was about 40 a, and the fitness coefficients (2.0-2.8) rapidly increased in early development stage, but then was sharply reduced (0.3-0.5), and then gradually dropped to almost 0. There were significant differences in the fitness at individual level (0-14 tree·cm -2 ) among different populations, but their values were low (close to zero). Based on the existing reproduction rate, the actual values of sexual reproduction and regeneration fitness were much lower than the predicted ones. Due to the low level of genetic fitness, the sexual reproductive ability of different populations all showed decreasing trends. The natural sexual regeneration ability tended to decline, while the fitness of T. ciliata var. pubescens further decreased. All those factors suggested higher investment risks. Therefore, the systems of sexual reproduction became unbalanced and deteriorating. We proposed that more studies, including breeding mating, pollination, seed setting, and genetic diversity evaluation, are needed. Moreover, we should provide suitable forest environment through cleaning up litter in the

Trajectories of risk for early sexual activity and early substance use in the Fast Track prevention program.

PubMed

2014-02-01

Children who exhibit early-starting conduct problems are more likely than their peers to initiate sexual activity and substance use at an early age, experience pregnancy, and contract a sexually-transmitted disease [STD], placing them at risk for HIV/AIDS. Hence, understanding the development of multi-problem profiles among youth with early-starting conduct problems may benefit the design of prevention programs. In this study, 1,199 kindergarten children (51% African American; 47% European American; 69% boys) over-sampled for high rates of aggressive-disruptive behavior problems were followed through age 18. Latent class analyses (LCA) were used to define developmental profiles associated with the timing of initiation of sexual activity, tobacco and alcohol/drug use and indicators of risky adolescent sex (e.g. pregnancy and STD). Half of the high-risk children were randomized to a multi-component preventive intervention (Fast Track). The intervention did not significantly reduce membership in the classes characterized by risky sex practices. However, additional analyses examined predictors of poor outcomes, which may inform future prevention efforts.

The role of early maturation, perceived popularity, and rumors in the emergence of internalizing symptoms among adolescent girls.

PubMed

Reynolds, Bridget M; Juvonen, Jaana

2011-11-01

Despite the widely reported link between early pubertal timing and internalizing symptoms among girls, less is known about the peer reputation of earlier maturing girls. The current study assesses whether early maturation is associated with perceived popularity and/or rumors, and whether these reputational factors help account for earlier maturing girls' vulnerability to emotional distress. Drawing on three waves of data collected from an ethnically diverse sample of middle school girls (n = 912), hierarchical multiple regression analyses revealed that more advanced development at the start of middle school predicted peer- and teacher-reported popularity as well as increased risk of being targeted for rumors. Mediation analyses suggested that popularity among boys can put earlier developing girls at risk for rumors. Finally, rumors acted as a partial mechanism through which early maturation was associated with subsequent internalizing symptoms. Knowledge of the peer mechanisms putting earlier developing girls at risk for psychosocial maladjustment can inform intervention and prevention efforts aimed at improving adolescent well-being.

Early Pubertal Maturation and Internalizing Problems in Adolescence: Sex Differences in the Role of Cortisol Reactivity to Interpersonal Stress

ERIC Educational Resources Information Center

Natsuaki, Misaki N.; Klimes-Dougan, Bonnie; Ge, Xiaojia; Shirtcliff, Elizabeth A.; Hastings, Paul D.; Zahn-Waxler, Carolyn

2009-01-01

An accumulating body of literature has shown a link between early pubertal maturation and internalizing problems, particularly among girls. Our knowledge is, however, limited with regard to what accounts for this association. Based on a hypothesis that early maturing girls have heightened stress sensitivity that increases the risk of internalizing…

Sex and sexual orientation disparities in adverse childhood experiences and early age at sexual debut in the United States: results from a nationally representative sample.

PubMed

Brown, Monique J; Masho, Saba W; Perera, Robert A; Mezuk, Briana; Cohen, Steven A

2015-08-01

Adverse childhood experiences (ACEs) have been linked to early sexual debut, which has been found to be associated with multiple adverse health outcomes. Sexual minorities and men tend to have earlier sexual debut compared to heterosexual populations and women, respectively. However, studies examining the association between ACEs and early sexual debut among men and sexual minorities are lacking. The aim of this study was to examine the sex and sexual orientation disparities in the association between ACEs and age at sexual debut. Data were obtained from Wave 2 of the National Epidemiologic Survey on Alcohol and Related Conditions. Logistic and linear regression models were used to obtain crude and adjusted estimates and 95% confidence intervals adjusting for age, race/ethnicity, income, education, insurance and marital status for the association between ACEs (neglect, physical/psychological abuse, sexual abuse, parental violence, and parental incarceration and psychopathology) and early sexual debut. Analyses were stratified by sex and sexual orientation. Larger effect estimates depicting the association between ACEs and sexual debut were seen for women compared to men, and among sexual minorities, particularly among men who have sex with men (MSM) and women who have sex with women (WSW), compared to heterosexuals. Sexual health education programs with a focus on delaying sexual debut among children and adolescents should also consider addressing ACEs, such as neglect, physical, psychological and sexual abuse, witnessing parental violence, and parental incarceration and psychopathology. Public health practitioners, researchers and sexual health education curriculum coordinators should consider these differences by sex and sexual orientation when designing these programs. Copyright © 2015 Elsevier Ltd. All rights reserved.

Maturation of EEG Power Spectra in Early Adolescence: A Longitudinal Study

ERIC Educational Resources Information Center

Cragg, Lucy; Kovacevic, Natasa; McIntosh, Anthony Randal; Poulsen, Catherine; Martinu, Kristina; Leonard, Gabriel; Paus, Tomas

2011-01-01

This study investigated the fine-grained development of the EEG power spectra in early adolescence, and the extent to which it is reflected in changes in peak frequency. It also sought to determine whether sex differences in the EEG power spectra reflect differential patterns of maturation. A group of 56 adolescents were tested at age 10 years and…

Determinants of early sexual initiation in the Pelotas birth cohort from 1982 to 2004-5, Southern Brazil

PubMed Central

Gonçalves, Helen; Béhague, Dominique P; Gigante, Denise P; Minten, Gicele C; Horta, Bernardo L; Victora, Cesar G; Barros, Fernando C

2009-01-01

OBJECTIVE To analyze social determinants of early sexual initiation among young adults from a birth cohort. METHODS Individuals from the 1982 birth cohort (N=4,297) were interviewed in 2004-5, city of Pelotas, Southern Brazil. Early sexual initiation (≤13 years of age) was the outcome. Descriptive and stratified analyses were performed according to sex. Variables analyzed were family income in 1982, ethnicity, young adult’s level of education and change in income (between 1982 and 2004-5). Ethnographic data were used to complement result analysis. RESULTS Prevalence of early sexual initiation was higher among black and mixed men, and those with low level of education and low family income in 1982 and 2004-5. More traditional male sexual role requirements, such as virility and sexual initiative, showed more repercussion and adherence from an early age among men. Young family women with higher income and level of education tended to delay their sexual initiation. Imposition of traditional values was found to influence early sexual initiation among men and women with lower level of education and income. CONCLUSIONS Results found re-established the economic factor as a determinant of behavior or uses of sexuality for both sexes. To focus on political efforts that help the economically disadvantaged to have opportunities and egalitarian future perspectives is an important strategy for health outcomes. PMID:19142343

Evaluation of the influence of prenatal transportation stress on GnRH-stimulated luteinizing hormone and testosterone secretion in sexually mature Brahman bulls

USDA-ARS?s Scientific Manuscript database

This study examined the relationships of prenatal transportation stress (PNS) with cortisol, luteinizing hormone (LH), and testosterone secretion before and after gonadotrophin releashing hormone (GnRH) stimulation of sexually mature Brahman bulls derived from the calf crop of 96 Brahman cows (48 co...

Early parental care is important for hippocampal maturation: evidence from brain morphology in humans.

PubMed

Rao, Hengyi; Betancourt, Laura; Giannetta, Joan M; Brodsky, Nancy L; Korczykowski, Marc; Avants, Brian B; Gee, James C; Wang, Jiongjiong; Hurt, Hallam; Detre, John A; Farah, Martha J

2010-01-01

The effects of early life experience on later brain structure and function have been studied extensively in animals, yet the relationship between childhood experience and normal brain development in humans remains largely unknown. Using a unique longitudinal data set including ecologically valid in-home measures of early experience during childhood (at age 4 and 8 years) and high-resolution structural brain imaging during adolescence (mean age 14 years), we examined the effects on later brain morphology of two dimensions of early experience: parental nurturance and environmental stimulation. Parental nurturance at age 4 predicts the volume of the left hippocampus in adolescence, with better nurturance associated with smaller hippocampal volume. In contrast, environmental stimulation did not correlate with hippocampal volume. Moreover, the association between hippocampal volume and parental nurturance disappears at age 8, supporting the existence of a sensitive developmental period for brain maturation. These findings indicate that variation in normal childhood experience is associated with differences in brain morphology, and hippocampal volume is specifically associated with early parental nurturance. Our results provide neuroimaging evidence supporting the important role of warm parental care during early childhood for brain maturation.

Early postnatal treatment with clomipramine induces female sexual behavior and estrous cycle impairment.

PubMed

Molina-Jiménez, Tania; Limón-Morales, Ofelia; Bonilla-Jaime, Herlinda

2018-03-01

Administration of clomipramine (CMI), a tricyclic antidepressant, in early stages of development in rats, is considered an animal model for the study of depression. This pharmacological manipulation has induced behavioral and physiological alterations, i.e., less pleasure-seeking behaviors, despair, hyperactivity, cognitive dysfunction, alterations in neurotransmitter systems and in HPA axis. These abnormalities in adult male rats are similar to the symptoms observed in major depressive disorders. One of the main pleasure-seeking behaviors affected in male rats treated with CMI is sexual behavior. However, to date, no effects of early postnatal CMI treatment have been reported on female reproductive cyclicity and sexual behavior. Therefore, we explored CMI administration in early life (8-21 PN) on the estrous cycle and sexual behavior of adult female rats. Compared to the rats in the early postnatal saline treatment (CTRL group), the CMI rats had fewer estrous cycles, fewer days in the estrous stage, and longer cycles during a 20-day period of vaginal cytology analysis. On the behavioral test, the CMI rats displayed fewer proceptive behaviors (hopping, darting) and had lower lordosis quotients. Also, they usually failed to display lordosis and only rarely manifested marginal or normal lordosis. In contrast, the CTRL rats tended to display normal lordosis. These results suggest that early postnatal CMI treatment caused long-term disruptions of the estrous cycle and female sexual behavior, perhaps by alteration in the hypothalamic-pituitary-gonadal (HPG) axes and in neuronal circuits involved in the regulation of the performance and motivational of sexual behavior as the noradrenergic and serotonergic systems. Copyright © 2018 Elsevier Inc. All rights reserved.

The maturation of cortical sleep rhythms and networks over early development.

PubMed

Chu, C J; Leahy, J; Pathmanathan, J; Kramer, M A; Cash, S S

2014-07-01

Although neuronal activity drives all aspects of cortical development, how human brain rhythms spontaneously mature remains an active area of research. We sought to systematically evaluate the emergence of human brain rhythms and functional cortical networks over early development. We examined cortical rhythms and coupling patterns from birth through adolescence in a large cohort of healthy children (n=384) using scalp electroencephalogram (EEG) in the sleep state. We found that the emergence of brain rhythms follows a stereotyped sequence over early development. In general, higher frequencies increase in prominence with striking regional specificity throughout development. The coordination of these rhythmic activities across brain regions follows a general pattern of maturation in which broadly distributed networks of low-frequency oscillations increase in density while networks of high frequency oscillations become sparser and more highly clustered. Our results indicate that a predictable program directs the development of key rhythmic components and physiological brain networks over early development. This work expands our knowledge of normal cortical development. The stereotyped neurophysiological processes observed at the level of rhythms and networks may provide a scaffolding to support critical periods of cognitive growth. Furthermore, these conserved patterns could provide a sensitive biomarker for cortical health across development. Copyright © 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Bile acid-FXRα pathways regulate male sexual maturation in mice

PubMed Central

Vega, Aurélie; Sédes, Lauriane; Rouaisnel, Betty; de Haze, Angélique; Baron, Silvère; Schoonjans, Kristina; Caira, Françoise; Volle, David H.

2016-01-01

The bile acid receptor Farnesol-X-Receptor alpha (FRXα) is a member of the nuclear receptor superfamily. FRXα is expressed in the interstitial compartment of the adult testes, which contain the Leydig cells. In adult, short term treatment (12 hours) with FRXα agonist inhibits the expression of steroidogenic genes via the induction of the Small heterodimer partner (SHP). However the consequences of FRXα activation on testicular pathophysiology have never been evaluated. We demonstrate here that mice fed a diet supplemented with bile acid during pubertal age show increased incidence of infertility. This is associated with altered differentiation and increase apoptosis of germ cells due to lower testosterone levels. At the molecular level, next to the repression of basal steroidogenesis via the induction expression of Shp and Dax-1, two repressors of steroidogenesis, the main action of the BA-FRXα signaling is through lowering the Leydig cell sensitivity to the hypothalamo-pituitary axis, the main regulator of testicular endocrine function. In conclusion, BA-FRXα signaling is a critical actor during sexual maturation. PMID:26848619

Sexual Maturity and Life Stage Influences Toxic Metal Accumulation in Croatian Brown Bears.

PubMed

Lazarus, Maja; Sekovanić, Ankica; Orct, Tatjana; Reljić, Slaven; Jurasović, Jasna; Huber, Đuro

2018-02-01

The influence of reproductive and (early) life stages on toxic metal levels was investigated in the brown bear (Ursus arctos), the largest mammalian predator species in Croatia. The purpose was to examine critical clusters in a population that might be at a higher risk of adverse health effects caused by metals as environmental contaminants. Levels of cadmium, mercury and lead in muscle, liver and kidney cortex of 325 male and 139 female bears, quantified by inductively coupled plasma mass spectrometry, were analysed according to distinct bear life stages (young: cub, yearling, subadult; mature: adult). Metal levels did not differ among sexes in young animals (< 4 years), except for mercury in muscles (higher in females), and adult females had higher cadmium and mercury. A trend of renal cadmium accumulation with age in immature male animals disappeared once they reached maturity, whereas for females this trend has only slowly declined in mature compared to immature bears. In early life stage (< 1 year), bear cubs had lower cadmium, comparable mercury, and higher lead in the kidneys than the bears of the following age category (yearlings). Due to a higher proportion of renal lead transfer from the mother to the cub compared with cadmium, it may be that the high burden of cadmium found in kidneys of older females has lower toxicological concern for their cubs than the lead content. Sex, reproductive, and life stages of bears were confirmed as important in assessing toxic metal burden.

Macro-level Age Norms for the Timing of Sexual Initiation and Adolescents’ Early Sexual Initiation in 17 European Countries

PubMed Central

Madkour, Aubrey Spriggs; de Looze, Margaretha; Ma, Ping; Halpern, Carolyn Tucker; Farhat, Tilda; ter Bogt, Tom F. M.; Ehlinger, Virginie; Nic Gabhainn, Saoirse; Currie, Candace; Godeau, Emmanuelle

2014-01-01

Purpose To examine the relationship between country-level age norms for sexual initiation timing and early sexual initiation (ESI) among adolescent boys and girls. Methods Nationally-representative data from 17 countries that participated in the 2006/07 European Social Survey (ESS-3, n=33,092) and the 2005/06 Health Behaviour in School-Aged Children Study (HBSC, n=27,702) were analyzed. Age norms were measured as the average country-level response to an item asking the age at which ESS respondents believed someone is too young to have sexual intercourse. HBSC respondents (aged 14-16) self-reported age at sexual initiation which we defined as early (<15 years) or not (≥15 years or no initiation). Control variables included age, family affluence, perceived socioeconomic status, family living arrangement, substance use, school attachment, and country-level legal age of consent. Multivariable three-level logistic models with random intercepts were run separately by sex. Results In multivariable analyses, higher overall age norms were associated with reduced likelihood of ESI among girls (AOR 0.60, 95% CI 0.45-0.79); associations with ESI were stronger for parent cohort (ages 31-65) norms (AOR 0.37, 95% CI 0.23-0.58) than for peer cohort (ages 15-20) norms (AOR 0.60, 95% CI 0.49-0.74). For boys, overall norms were also significantly negatively associated with ESI (AOR 0.68, 95% CI 0.46-0.99), as were parent cohort norms (AOR 0.66, 95% CI 0.45-0.96). Peer cohort norms were not significantly related to boys’ ESI. Conclusion Macro-level cultural norms may impact adolescents’ sexual initiation timing. Research exploring the sexual health outcomes of early initiators in countries with contrasting age norms is warranted. PMID:24508092

Sexual Desire During the Menopausal Transition and Early Postmenopause: Observations from the Seattle Midlife Women's Health Study

PubMed Central

Mitchell, Ellen Sullivan; Smith-Di Julio, Kathy

2010-01-01

Abstract Aims To describe levels of sexual desire across the menopausal transition (MT) and early postmenopause (PM), including effects of age, MT-related factors, health, stress, symptoms (hot flash, sleep, mood), and social opportunity factors. Methods A subset of Seattle Midlife Women's Health Study (SMWHS) participants who provided data during the early reproductive, early and late menopausal transition stages, or postmenopause (n = 286), including menstrual calendars for staging the MT, annual health reports between 1990 and 2005, and morning urine samples assayed for estrone glucuronide (E1G), testosterone (T), and follicle-stimulating hormone (FSH) was included. Multilevel modeling using the R program was used to test factors related to sexual desire. Results Women experienced a significant decrease in sexual desire during the late MT stage (p < 0.01) and early PM (p < 0.0001). Those with higher urinary E1G and T reported significantly higher levels of sexual desire, whereas those with higher FSH levels reported significantly lower sexual desire (p < 0.0001, 0.06, and 0.0002, respectively). Women using hormone therapy also reported higher sexual desire (p = 0.02). Those reporting higher perceived stress reported lower sexual desire (p < 0.0001), but history of sexual abuse did not have a significant effect. Those most troubled by symptoms of hot flashes, fatigue, depressed mood, anxiety, difficulty getting to sleep, early morning awakening, and awakening during the night also reported significantly lower sexual desire (p range from <0.03 to 0.0001), but there was no effect of vaginal dryness. Women with better perceived health reported higher sexual desire (p < 0.0001), and those reporting more exercise and more alcohol intake also reported greater sexual desire (p < 0.0001). Having a partner was associated with lower sexual desire. Conclusions Clinicians working with women traversing the MT should be aware that promoting

THE IMPACT OF SEXUAL HARASSMENT ON DEPRESSIVE SYMPTOMS DURING THE EARLY OCCUPATIONAL CAREER

PubMed Central

Houle, Jason N.; Staff, Jeremy; Mortimer, Jeylan T.; Uggen, Christopher; Blackstone, Amy

2011-01-01

Sexual harassment has been theorized as a stressor with consequences for the physical and mental health of its targets. Though social scientists have documented a negative association between sexual harassment and mental health, few longitudinal studies have investigated the association between sexual harassment and depressive symptoms. Using longitudinal survey data from the Youth Development Study, combined with in-depth interviews, this article draws on Louise Fitzgerald’s theoretical framework, stress theory, and the life course perspective to assess the impact of sexual harassment on depressive affect during the early occupational career. In support of Fitzgerald’s model, our findings confirm that sexual harassment is a stressor that is associated with increased depressive symptoms. Our quantitative results show that women and men who experience more frequent sexual harassment at work have significantly higher levels of depressed mood than non-harassed workers, even after controlling for prior harassment and depressive symptoms. Moreover, we find evidence that sexual harassment early in the career has long-term effects on depressive symptoms in adulthood. Interviews with a subset of our survey respondents point to a variety of coping strategies and reveal further links between harassment and other aspects of mental health, such as anger and self-doubt. PMID:22140650

THE IMPACT OF SEXUAL HARASSMENT ON DEPRESSIVE SYMPTOMS DURING THE EARLY OCCUPATIONAL CAREER.

PubMed

Houle, Jason N; Staff, Jeremy; Mortimer, Jeylan T; Uggen, Christopher; Blackstone, Amy

2011-07-01

Sexual harassment has been theorized as a stressor with consequences for the physical and mental health of its targets. Though social scientists have documented a negative association between sexual harassment and mental health, few longitudinal studies have investigated the association between sexual harassment and depressive symptoms. Using longitudinal survey data from the Youth Development Study, combined with in-depth interviews, this article draws on Louise Fitzgerald's theoretical framework, stress theory, and the life course perspective to assess the impact of sexual harassment on depressive affect during the early occupational career. In support of Fitzgerald's model, our findings confirm that sexual harassment is a stressor that is associated with increased depressive symptoms. Our quantitative results show that women and men who experience more frequent sexual harassment at work have significantly higher levels of depressed mood than non-harassed workers, even after controlling for prior harassment and depressive symptoms. Moreover, we find evidence that sexual harassment early in the career has long-term effects on depressive symptoms in adulthood. Interviews with a subset of our survey respondents point to a variety of coping strategies and reveal further links between harassment and other aspects of mental health, such as anger and self-doubt.

Early maladaptive schemas and aggressive sexual behavior: a preliminary study with male college students.

PubMed

Sigre-Leirós, Vera Lúcia; Carvalho, Joana; Nobre, Pedro

2013-07-01

The influence of adverse early attachment experiences on the development of aggressive sexual behavior has been demonstrated. Nonetheless, there is a gap in the literature regarding the conceptualization of this behavior according to developmental psychopathology models. The purpose of the present study was to investigate a potential association between Early Maladaptive Schemas (EMSs) and aggressive sexual behavior. A total of 166 male college students participated in the study. Participants were divided into two comparative groups according to data from the Sexual Experiences Survey-Short Form Perpetration (SES-SFP): Group of individuals with history of aggressive sexual behavior (N = 37) and Group of individuals without history of aggressive sexual behavior (N = 129). Aggressive sexual behavior was measured by the SES-SFP, and EMSs were measured by the Young Schema Questionnaire (YSQ-S3). Results showed that students who have committed any form of sexually aggressive behavior exhibited significantly higher levels of EMSs from the Disconnection and Rejection domain (namely, Mistrust/Abuse schema), from the Impaired Autonomy and Performance domain (namely, Dependence/Incompetence schema), and from the Overvigilance and Inhibition domain (namely, Negativity/Pessimism schema). These preliminary findings suggest that the EMSs were associated with aggressive sexual behavior, but further investigation is warranted. © 2012 International Society for Sexual Medicine.

Parents’ Support and Knowledge of Their Daughters’ Lives and Females’ Early Sexual Initiation in Nine European Countries

PubMed Central

Madkour, Aubrey Spriggs; Farhat, Tilda; Halpern, Carolyn Tucker; Nic Gabhainn, Saoirse; Godeau, Emmanuelle

2013-01-01

Context The association between early sexual initiation and parenting practices (e.g., support and knowledge) has not been tested in multiple European population-based samples using the same instrument. Methods Data provided by females (age 14-16) participating in the 2005-06 Health Behaviors in School-Aged Children (HBSC) survey conducted in Austria, Finland, Greece, Hungary, Iceland, Lithuania, Romania, Spain and Ukraine were used (n=7,466). The dependent variable was early sexual initiation (<16). The main independent variables were maternal and paternal support and knowledge of daily activities. Univariate, bivariate and multivariable analyses were run with standard error corrections and weights. Results Prevalence of early sexual initiation ranged from a low of 7% (Romania) to a high of 35% (Iceland). In bivariate analyses, maternal and paternal support were significantly negatively related to adolescent females’ early sexual initiation in a majority of countries. In models with demographic controls, parental support was significantly negatively related to early sexual initiation (AOR = 0.80 maternal, 0.74 paternal). After adding parental knowledge, early sexual initiation was no longer associated with parental support, but was significantly negatively related to parental knowledge (AOR = 0.69 maternal and paternal). These patterns held across countries. Conclusions Negative associations between parental support and early initiation were largely explained by parental knowledge, suggesting either that knowledge is more important than support or that knowledge mediates the association between support and early initiation. Providers should counsel parents regarding the importance of knowledge of their daughters’ daily lives, which may be enhanced through developing supportive relationships. PMID:22958661

Predicting sexual coercion in early adulthood: The transaction among maltreatment, gang affiliation, and adolescent socialization of coercive relationship norms.

PubMed

Ha, Thao; Kim, Hanjoe; Christopher, Caroline; Caruthers, Allison; Dishion, Thomas J

2016-08-01

This study tested a transactional hypothesis predicting early adult sexual coercion from family maltreatment, early adolescent gang affiliation, and socialization of adolescent friendships that support coercive relationship norms. The longitudinal study of a community sample of 998 11-year-olds was intensively assessed in early and middle adolescence and followed to 23-24 years of age. At age 16-17 youth were videotaped with a friend, and their interactions were coded for coercive relationship talk. Structural equation modeling revealed that maltreatment predicted gang affiliation during early adolescence. Both maltreatment and gang affiliation strongly predicted adolescent sexual promiscuity and coercive relationship norms with friends at age 16-17 years. Adolescent sexual promiscuity, however, did not predict sexual coercion in early adulthood. In contrast, higher levels of observed coercive relationship talk with a friend predicted sexual coercion in early adulthood for both males and females. These findings suggest that peers have a socialization function in the development of norms prognostic of sexual coercion, and the need to consider peers in the promotion of healthy relationships.

Effects of sex pheromones and sexual maturation on locomotor activity in female sea lamprey (Petromyzon marinus)

USGS Publications Warehouse

Walaszczyk, Erin J.; Johnson, Nicholas S.; Steibel, Juan Pedro; Li, Weiming

2013-01-01

Synchronization of male and female locomotor rhythmicity can play a vital role in ensuring reproductive success. Several physiological and environmental factors alter these locomotor rhythms. As sea lamprey, Petromyzon marinus, progress through their life cycle, their locomotor activity rhythm changes multiple times. The goal of this study was to elucidate the activity patterns of adult female sea lamprey during the sexual maturation process and discern the interactions of these patterns with exposure to male pheromones. During these stages, preovulated and ovulated adult females are exposed to sex pheromone compounds, which are released by spermiated males and attract ovulated females to the nest for spawning. The locomotor behavior of adult females was monitored in a natural stream with a passive integrated tag responder system as they matured, and they were exposed to a sex pheromone treatment (spermiated male washings) or a control (prespermiated male washings). Results showed that, dependent on the hour of day, male sex pheromone compounds reduce total activity (p < 0.05) and cause increases in activity during several daytime hours in preovulated and ovulated females. These results are one of the first examples of how sex pheromones modulate a locomotor rhythm in a vertebrate, and they suggest that the interaction between maturity stage and sex pheromone exposure contributes to the differential locomotor rhythms found in adult female sea lamprey. This phenomenon may contribute to the reproductive synchrony of mature adults, thus increasing reproductive success in this species.

Surgical management of patients with a history of early Le Fort III advancement after they have attained skeletal maturity.

PubMed

Caterson, E J; Shetye, Pradip R; Grayson, Barry H; McCarthy, Joseph G

2013-10-01

The classic Le Fort III procedure was recommended in syndromic craniosynostotic children to reduce exorbitism, improve airway function, and decrease dysmorphism. This study reports on a cohort of syndromic craniosynostosis patients who have undergone early primary subcranial (classic Tessier) Le Fort III advancement and who have been followed longitudinally through skeletal maturity and beyond. In this study, the Le Fort III advancements all occurred between the ages of 3 to 5 years, with a mean age of 4.6 years. Subsequently, these early Le Fort III patients were followed throughout development with longitudinal dental, medical, radiographic, and photographic evaluations conducted through skeletal maturity and beyond. For study inclusion, the patients had to have preoperative medical photographs and cephalometric studies at 6 months and 1, 5, and 10 years postoperatively after the primary Le Fort III advancement as well as cephalometric documentation 6 months and 1 year after the secondary midface advancement after skeletal maturity. After early or primary Le Fort III advancement, there was no evidence of relapse and only minimal anterior or horizontal postoperative growth of the midface. However, there was also a return of occlusal disharmony from "anticipated" mandibular growth, approaching a maximum at skeletal maturity. The dysmorphic concave facial profile and malocclusion, and airway and ocular considerations, provided the impetus for secondary midface surgery after skeletal maturity was attained. The data demonstrate that early Le Fort III advancement performed before the age of mixed dentition does not obviate the need for a secondary advancement after skeletal maturity is reached. Therapeutic, IV.

Early and risky sexual behavior in a sample of rural adolescents.

PubMed

Rew, Lynn; Carver, Tracy; Li, Chia-Chun

2011-01-01

Early and risky sexual behavior has been studied primarily in urban adolescents. The purpose of this analysis was to identify psychosocial variables associated with sexual-risk behaviors in a sample of mostly rural adolescents. Six hypotheses were tested, using a resilience framework and data from an ongoing longitudinal study of 255 adolescents. Sexual-risk status did not differ statistically by gender (p=.654) or socioeconomic status (p=.590). However, adolescents who engaged in sexual-risk behaviors reported significantly lower religiosity (p<.003), lower parental monitoring (p=.002), lower social connectedness (p=.007), and higher levels of peer influence (p<.001) than those engaged in no sexual-risk behaviors. Adolescents engaged in sexual-risk behaviors were also engaged in significantly more other health-risk behaviors such as smoking and drinking (p<.001). Findings may be useful for developing interventions that focus on the social influences of peers and parents on rural youth. Copyright © Informa Healthcare USA, Inc.

Affect and sexual behavior in the transition to university.

PubMed

Dalton, Andrea L; Galambos, Nancy L

2009-10-01

This research applied a lifespan developmental framework to the study of sexual behavior among late adolescents by examining monthly covariations of penetrative and oral sex with positive and negative affect across the first year of university. Participants were 177 Canadian students who completed baseline questionnaires, followed by six monthly, web-based questionnaires assessing sexual behaviors and affect. Multilevel analyses revealed an average positive relation between oral sex and positive affect. Of six variables, five predicted individual differences in covariation between sex and affect: psychosocial maturity (immature and semi-mature status), attitudes toward sex, prior sexual experience, and living situation. During months when participants reported sexual behavior, psychosocially mature students reported more positive affect than did less mature students; students with more permissive attitudes reported more positive affect than did students with less permissive attitudes; students with no penetrative sexual experience reported more positive affect than students who had penetrative sexual experience; and living away from parents was associated with less negative affect. Implications for further study of sexual behavior from a developmental perspective are discussed.

Gender differences in masturbation and the relation of masturbation experience in preadolescence and/or early adolescence to sexual behavior and sexual adjustment in young adulthood.

PubMed

Leitenberg, H; Detzer, M J; Srebnik, D

1993-04-01

A comparison of male and female masturbation practices was undertaken in a sample of university students to determine if the long-standing finding that young adult men in this country masturbate more than young adult women was still evident in the 1980s. Despite the efforts in the past quarter century to encourage women in our society to take greater responsibility for their own bodies and their own sexuality and to engage in more sexual self-exploration and self-stimulation, results show that women continue to masturbate much less than men. Twice as many men as women had ever masturbated and the men who masturbated did so three times more frequently during early adolescence and young adulthood than the women who masturbated during these same age periods. A second purpose of this study was to determine whether having masturbation experience during preadolescence and/or early adolescence was related to intercourse experience, sexual satisfaction, sexual arousal, or sexual difficulties in relationships during young adulthood. No such linkage was observed, suggesting that early masturbation experience is neither beneficial nor harmful to sexual adjustment in young adulthood.

Characterization of cytological changes, IgA, IgG and IL-8 levels and pH value in the vagina of prepubertal and sexually mature Ellegaard Göttingen minipigs during an estrous cycle.

PubMed

Lorenzen, Emma; Agerholm, Jørgen Steen; Grossi, Anette Blak; Bojesen, Anders Miki; Skytte, Christina; Erneholm, Karin; Follmann, Frank; Jungersen, Gregers

2016-06-01

The pig is increasingly used as an advanced animal model of the genital tract in women and knowledge on the genital immune system is therefore needed. In this study, evaluation of vaginal smears revealed that almost no neutrophils or other leukocytes were present in the vaginal mucosa of prepubertal minipigs (n = 10). In sexually mature minipigs (n = 10), evaluated through an estrous cycle, there was an increase in number of mucosal neutrophils and other leukocytes during estrus. The level of total IgA on the vaginal mucosa increased during diestrus. The level of total IgG showed no significant changes through the cycle. The vaginal IgA level in the prepubertal minipigs was similar to the low estrus level in sexually mature minipigs, and the IgG level in prepubertal was similar to the stable level in the sexually mature minipigs. Copyright © 2016 Elsevier Ltd. All rights reserved.

The effect of first nocturnal ejaculation timing on risk and sexual behaviors of Korean male adolescents

PubMed Central

Lee, Mi-Ji; Yang, Go-Eun; Chueh, Hee Won; Park, Jae Hong

2017-01-01

Purpose This study evaluated the effect of first nocturnal ejaculation timing on risk and sexual behaviors of Korean male adolescents. Methods We analyzed data from the 10th edition of the Korea Youth Risk Behavior Web-based survey that was conducted with male high school adolescents in grades 10–12. The survey included 17,907 adolescents, and 10,326 responded their experience of first nocturnal ejaculation. Of these, 595 had their first nocturnal ejaculation in ≤grade 4 (“early puberty”) and 9,731 had their first nocturnal ejaculation in ≥grade 5 (“normal puberty”). We analyzed differences between these 2 groups in risk and sexual behaviors. Results Early first nocturnal ejaculation showed a positive association with sexual intercourse (odds ratio [OR], 3.27; 95% confidence interval [CI], 2.56–4.17), sexual debut at elementary school age (OR, 7.45; 95% CI, 5.00–11.10), and having had a sexually transmitted disease (OR, 6.60; 95% CI, 3.94–11.08). After a multiple logistic regression to adjust for socio-demographic variables, early first nocturnal ejaculation was still positively associated with sexual intercourse (OR, 2.73; 95% CI, 2.03–3.69), sexual debut at elementary school age (OR, 5.96; 95% CI, 3.47–10.22), and having had a sexually transmitted disease (OR, 5.17; 95% CI, 2.52–10.20). Early first nocturnal ejaculation was positively associated with alcohol consumption, smoking, and substance use. However, this was not statistically significant after adjusting for several socio-demographic variables. Conclusion There is a positive association between early nocturnal ejaculation and sexual behaviors in male adolescents. Proactive education about sexual behaviors is required for adolescents who reach sexual maturity early. PMID:28443258

Transcriptome Analysis and Differential Gene Expression on the Testis of Orange Mud Crab, Scylla olivacea, during Sexual Maturation

PubMed Central

Waiho, Khor; Fazhan, Hanafiah; Shahreza, Md Sheriff; Moh, Julia Hwei Zhong; Noorbaiduri, Shaibani; Wong, Li Lian; Sinnasamy, Saranya

2017-01-01

Adequate genetic information is essential for sustainable crustacean fisheries and aquaculture management. The commercially important orange mud crab, Scylla olivacea, is prevalent in Southeast Asia region and is highly sought after. Although it is a suitable aquaculture candidate, full domestication of this species is hampered by the lack of knowledge about the sexual maturation process and the molecular mechanisms behind it, especially in males. To date, data on its whole genome is yet to be reported for S. olivacea. The available transcriptome data published previously on this species focus primarily on females and the role of central nervous system in reproductive development. De novo transcriptome sequencing for the testes of S. olivacea from immature, maturing and mature stages were performed. A total of approximately 144 million high-quality reads were generated and de novo assembled into 160,569 transcripts with a total length of 142.2 Mb. Approximately 15–23% of the total assembled transcripts were annotated when compared to public protein sequence databases (i.e. UniProt database, Interpro database, Pfam database and Drosophila melanogaster protein database), and GO-categorised with GO Ontology terms. A total of 156,181 high-quality Single-Nucleotide Polymorphisms (SNPs) were mined from the transcriptome data of present study. Transcriptome comparison among the testes of different maturation stages revealed one gene (beta crystallin like gene) with the most significant differential expression—up-regulated in immature stage and down-regulated in maturing and mature stages. This was further validated by qRT-PCR. In conclusion, a comprehensive transcriptome of the testis of orange mud crabs from different maturation stages were obtained. This report provides an invaluable resource for enhancing our understanding of this species’ genome structure and biology, as expressed and controlled by their gonads. PMID:28135340

Family homework and school-based sex education: delaying early adolescents' sexual behavior.

PubMed

Grossman, Jennifer M; Frye, Alice; Charmaraman, Linda; Erkut, Sumru

2013-11-01

Early sexual activity can undermine adolescents' future school success and health outcomes. The purpose of this study was to assess the role of a family homework component of a comprehensive sex education intervention in delaying sexual initiation for early adolescents and to explore what social and contextual factors prevent adolescents from completing these family homework activities. This mixed methods study included 6th- and 7th-grade survey responses from 706 students at 11 middle school schools receiving a sex education intervention, as well as interviews from a subset of 33, 7th-grade students from the larger sample. Adolescents who completed more family homework assignments were less likely to have vaginal intercourse in 7th grade than those who completed fewer assignments, after controlling for self-reports of having had vaginal intercourse in 6th grade and demographic variables. Participants' explanations for not completing assignments included personal, curriculum, and family-based reasons. Family homework activities designed to increase family communication about sexual issues can delay sex among early adolescents and contribute to school-based sex education programs. Successful sex education programs must identify and address barriers to family homework completion. © 2013, American School Health Association.

Relative growth and morphological sexual maturity size of the freshwater crab Trichodactylus borellianus (Crustacea, Decapoda, Trichodactylidae) in the Middle Paraná River, Argentina

PubMed Central

Williner, Verónica; Torres, María Victoria; Carvalho, Débora Azevedo; König, Natalia

2014-01-01

Abstract The relative growth of a number of morphological dimensions of the South American freshwater crab Trichodactylus borellianus (Trichodactylidae) were compared and related to sexual dimorphism. Crabs were collected from ponds in the Middle Paraná River in Argentina. A regression model with segmented relationship was used to test for relative growth between these measurements where breakpoints infer the body size at which crabs reach sexual maturity. In both sexes the carapace width and the length, height, and thickness of the right and left chelae were measured, as well as the male pleopod length and the female abdomen width. All of these measurements were found to show positive allometry with the exception of the male pleopod length and the left chelae, which did not show a breakpoint. In females the breakpoint for the abdomen width inferred a morphological sexual maturity at carapace width 6.9 mm. In males the break point for the pleopod length was at carapace width 6.6 mm, with that for the chelae measurements was between carapace widths 6.4 and 6.9 mm. The relative growth pattern in Trichodactylus borellianus was found to be similar to that recorded for other species of the family Trichodactylidae. PMID:25561835

Reasons for delaying or engaging in early sexual initiation among adolescents in Nigeria

PubMed Central

Ankomah, Augustine; Mamman-Daura, Fatima; Omoregie, Godpower; Anyanti, Jennifer

2011-01-01

Background Annually, over 1 million births in Nigeria are to teenage mothers. Many of these pregnancies are unwanted and these mothers are also exposed to the risk of human immunodeficiency virus (HIV) infection. Sexual abstinence is a critical preventative health strategy. Several quantitative studies in Nigeria have identified the correlates and determinants of early sex, yet few have explored in depth the underlying reasons for early sex. This paper explores both the key factors that motivate some unmarried young people to engage in early sex and reasons why some delay. Methods This qualitative study was based on data from 30 focus group discussions held with unmarried 14- to 19-year-olds in four geographically and culturally dispersed Nigerian states. Focus groups were stratified by sexual experience to capture variations among different subgroups. Results Several reasons for early premarital sex were identified. The “push” factors included situations where parents exposed young female adolescents to street trading. “Pull” factors, particularly for males, included the pervasive viewing of locally produced movies, peer pressure and, for females, transactional sex (where adolescent girls exchange sex for gifts, cash, or other favors). Also noted were overtly coercive factors, including rape. There were also myths and misconceptions that “justified” early sexual initiation. Reasons cited for delay included religious injunction against premarital sex; disease prevention (especially HIV/acquired immunodeficiency syndrome); fear of pregnancy, and linked to this, the fear of dropping out of school; and, for females, the fear of bringing shame to the family, which could lead to their inability to get a “good” husband in the future. Conclusion The differences observed between sexually active and abstinent adolescents were that the latter were more confident, had greater determination, and, most important, deployed refusal skills to delay first sex

Sexual Abuse Exposure Alters Early Processing of Emotional Words: Evidence from Event-Related Potentials

PubMed Central

Grégoire, Laurent; Caparos, Serge; Leblanc, Carole-Anne; Brisson, Benoit; Blanchette, Isabelle

2018-01-01

This study aimed to compare the time course of emotional information processing between trauma-exposed and control participants, using electrophysiological measures. We conceived an emotional Stroop task with two types of words: trauma-related emotional words and neutral words. We assessed the evoked cerebral responses of sexual abuse victims without post-traumatic stress disorder (PTSD) and no abuse participants. We focused particularly on an early wave (C1/P1), the N2pc, and the P3b. Our main result indicated an early effect (55–165 ms) of emotionality, which varied between non-exposed participants and sexual abuse victims. This suggests that potentially traumatic experiences modulate early processing of emotional information. Our findings showing neurobiological alterations in sexual abuse victims (without PTSD) suggest that exposure to highly emotional events has an important impact on neurocognitive function even in the absence of psychopathology. PMID:29379428

Effect of Forced Sexual Intercourse on Associations between Early Sexual Debut and Other Health Risk Behaviors among US High School Students

ERIC Educational Resources Information Center

Lowry, Richard; Robin, Leah; Kann, Laura

2017-01-01

Background: Previous research on associations between early sexual debut and other health risk behaviors has not examined the effect of forced sexual intercourse on those associations. Methods: We analyzed data from a nationally representative sample of 19,240 high school students in the United States, age =16 years, to describe the effect of…

Does Father Absence Place Daughters at Special Risk for Early Sexual Activity and Teenage Pregnancy?

PubMed Central

Ellis, Bruce J.; Bates, John E.; Dodge, Kenneth A.; Fergusson, David M.; Horwood, L. John; Pettit, Gregory S.; Woodward, Lianne

2009-01-01

The impact of father absence on early sexual activity and teenage pregnancy was investigated in longitudinal studies in the United States (N = 242) and New Zealand (N = 520), in which community samples of girls were followed prospectively from early in life (5 years) to approximately age 18. Greater exposure to father absence was strongly associated with elevated risk for early sexual activity and adolescent pregnancy. This elevated risk was either not explained (in the U.S. study) or only partly explained (in the New Zealand study) by familial, ecological, and personal disadvantages associated with father absence. After controlling for covariates, there was stronger and more consistent evidence of effects of father absence on early sexual activity and teenage pregnancy than on other behavioral or mental health problems or academic achievement Effects of father absence are discussed in terms of life-course adversity, evolutionary psychology, social learning, and behavior genetic models. PMID:12795391

Management of Sexual Maturation and Natural Spawning of Captive- Reared Yellowtail Kingfish, Seriola lalandi, in an Indoor Rearing Tank.

PubMed

Yang, Sang Geun; Ji, Seung Cheol; Lim, Sang Gu; Hur, Sang Woo; Jeong, Minhwan; Lee, Chi Hoon; Kim, Bong Seok; Lee, Young-Don

2016-06-01

This study describes results on sexual maturation and characteristics of natural spawned eggs to develop a method for the production of stable, healthy fertilized eggs from captive-reared yellowtail kingfish, Seriola lalandi. A total of 59 yellowtail kingfish were captured off the coast of Jeju Island, after which the broodstock was cultured in indoor culture tank (100 m(3)) until they were 6.1-14.9 kg in body weight. As part of the rearing management for induced sex maturation, the intensity of illumination was maintained at 130 lux. The photoperiod (light/dark; L/D) was set to a 12 L/12 D from October 2013 to January 2014, and 15 L/9 D from February 2014 to June 2014. Feeds comprised mainly EP (Extruded Pellets), with squid cuttlefish added for improvement of egg quality, and was given from April to June 2014. The first spawning of yellowtail kingfish occurred in May 3, 2014, at a water temperature of 17.0°C. Spawning continued until June 12, 2014, with the water temperature set at 20.5°C. Time of spawning was 26 times at this period. The total number of eggs that spawned during the spawning period was 4,449×10(3). The buoyant rate of spawning eggs and fertilization rate of buoyant eggs during the spawned period were 76.1% and 100%, respectively. The diameters of the egg and oil globule were 1.388 ± 0.041 mm and 0.378 ± 0.029 mm, respectively, which was higher in early eggs than in those from late during the spawned period.

Same-Sex Sexuality and Adolescent Psychological Well-Being: The influence of sexual orientation, early reports of same-sex attraction, and gender

PubMed Central

Jager, Justin; Davis-Kean, Pamela E.

2012-01-01

Emerging research has shown that those of sexual-minority (SM) status (i.e., those exhibiting same-sex sexuality) report lower levels of psychological well-being. This study aimed to assess whether this relation is largely in place by the onset of adolescence, as it is for other social statuses, or whether it continues to emerge over the adolescent years, a period when SM youth face numerous challenges. Moreover, the moderating influence of sexual orientation (identification), early (versus later) reports of same-sex attractions, and gender were also examined. Using data from Add Health, multiple-group latent growth curve analyses were conducted to examine growth patterns in depressive affect and self-esteem. Results suggested that psychological well-being disparities between SM and non-SM were generally in place by early adolescence. For many, the remainder of adolescence was a recovery period when disparities narrowed over time. Early and stable reporting of same-sex attractions was associated with a greater initial deficit in psychological well-being, especially among males, but it was also associated with more rapid recovery. Independent of the timing and stability of reported same-sex attractions over time, actual sexual orientation largely failed to moderate the relation between SM status and psychological well-being. Importantly, the sizable yet understudied subgroup that identified as heterosexual but reported same-sex attractions appeared to be at substantial risk. PMID:22505839

Sending and Receiving Text Messages with Sexual Content: Relations with Early Sexual Activity and Borderline Personality Features in Late Adolescence

PubMed Central

Brinkley, Dawn Y.; Ackerman, Robert A.; Ehrenreich, Samuel E.; Underwood, Marion K.

2017-01-01

This research examined adolescents’ written text messages with sexual content to investigate how sexting relates to sexual activity and borderline personality features. Participants (N = 181, 85 girls) completed a measure of borderline personality features prior to 10th grade and were subsequently given smartphones configured to capture the content of their text messages. Four days of text messaging were micro-coded for content related to sex. Following 12th grade, participants reported on their sexual activity and again completed a measure of borderline personality features. Results showed that engaging in sexting at age 16 was associated with reporting an early sexual debut, having sexual intercourse experience, having multiple sex partners, and engaging in drug use in combination with sexual activity two years later. Girls engaging in sex talk were more likely to have had sexual intercourse by age 18. Text messaging about hypothetical sex in grade 10 also predicted borderline personality features at age 18. These findings suggest that sending text messages with sexual content poses risks for adolescents. Programs to prevent risky sexual activity and to promote psychological health could be enhanced by teaching adolescents to use digital communication responsibly. PMID:28824224

Sending and Receiving Text Messages with Sexual Content: Relations with Early Sexual Activity and Borderline Personality Features in Late Adolescence.

PubMed

Brinkley, Dawn Y; Ackerman, Robert A; Ehrenreich, Samuel E; Underwood, Marion K

2017-05-01

This research examined adolescents' written text messages with sexual content to investigate how sexting relates to sexual activity and borderline personality features. Participants (N = 181, 85 girls) completed a measure of borderline personality features prior to 10 th grade and were subsequently given smartphones configured to capture the content of their text messages. Four days of text messaging were micro-coded for content related to sex. Following 12 th grade, participants reported on their sexual activity and again completed a measure of borderline personality features. Results showed that engaging in sexting at age 16 was associated with reporting an early sexual debut, having sexual intercourse experience, having multiple sex partners, and engaging in drug use in combination with sexual activity two years later. Girls engaging in sex talk were more likely to have had sexual intercourse by age 18. Text messaging about hypothetical sex in grade 10 also predicted borderline personality features at age 18. These findings suggest that sending text messages with sexual content poses risks for adolescents. Programs to prevent risky sexual activity and to promote psychological health could be enhanced by teaching adolescents to use digital communication responsibly.

Supplementation with CTGF, SDF1, NGF, and HGF promotes ovine in vitro oocyte maturation and early embryo development.

PubMed

Wang, D H; Ren, J; Zhou, C J; Han, Z; Wang, L; Liang, C G

2018-05-17

The strategies for improving the in vitro maturation (IVM) of domestic animal oocytes focus on promoting nuclear and cytoplasmic maturation. The identification of paracrine factors and their supplementation in the culture medium represent effective approaches for oocyte maturation and embryo development. This study investigated the effects of paracrine factor supplementation including connective tissue growth factor (CTGF), nerve growth factor (NGF), hepatocyte growth factor (HGF), and stromal derived factor 1 (SDF1) on ovine oocytes and early parthenogenetic embryos using an in vitro culture system. First, we identified the optimal concentrations of CTGF (30 ng/mL), SDF1 (10 ng/mL), NGF (3 ng/mL), and HGF (100 ng/mL) for promoting oocyte maturation, which combined, induced nuclear maturation in 94.19% of oocytes. This combination also promoted cumulus cell expansion and inhibited oocyte/cumulus apoptosis, while enabling a larger proportion (33.04%) of embryos to develop into blastocysts than in the controls and prevented embryo apoptosis. These novel findings demonstrate that the paracrine factors CTGF, SDF1, NGF, and HGF facilitate ovine oocyte and early parthenogenetic embryo development in vitro. Thus, supplementation with these factors may help optimize the IVM of ovine oocytes and early parthenogenetic embryo development strategies. Copyright © 2018 Elsevier Inc. All rights reserved.

Do mature forest birds prefer early-successional habitat during the post-fledging period?

Treesearch

Carlin C. Chandler; David I. King; Richard B. Chandler

2012-01-01

Recent studies have highlighted the importance of the post-fledging period to bird populations, suggesting that the importance of this portion of the life cycle is equal to or greater than the nesting period. Nevertheless, few studies have compared abundance of forest nesting species between mature forest and early-successional habitats while controlling for...

A Curriculum Proposal for the Development of Maturity in Students.

ERIC Educational Resources Information Center

Jelinek, James John

Development of the mature person is a necessary theme for educational design in contemporary society. A structured definition of the term "maturity" is needed which can be applied to the design of educational experience. The author suggests that there are six criteria of maturity: intelligence, responsiblity, articulation, empathy, sexuality, and…

"This base stallion trade": he-whores and male sexuality on the early modern stage.

PubMed

Panek, Jennifer

2010-01-01

Recent scholarship on early modern male sexuality has stressed the threat that sexual relations with women were believed to pose to manhood. Focusing on such plays as Middleton's Your Five Gallants (c. 1608), Fletcher and Massinger's The Custom of The Country (c.1620), and Davenant's The Just Italian (1630), this paper analyzes representations of male prostitutes for women to argue that cultural attitudes toward male sexual performance were more complex and self-contradictory than generally acknowledged. The patriarchal codes that warned against effeminating sexual desire and advocated parsimonious seminal “spending” are undermined by their own inherent corollary: the most masculine man is one who can demonstrate unlimited seminal capacity. Furthermore, it has been posited that the early modern period marked the beginning of a shift from “reproductive” to “performative” constructions of manhood, in which the manhood-affirming aspects of male sexuality gradually became unmoored from their traditional association with bloodlines and attached instead to penetrative sexual conquest. The class implications of this shift inform patriarchal anxieties about the superior sexual stamina of servant-class men and their bodily “service” to elite women. Representing a fantasy of empowering male sexuality that relies on detaching virile performance from effeminating desire—a physiologically absurd notion—and on providing sexual “service” while leaving intact both class and gender hierarchies, a successful he-whore like Middleton's Tailby or Davenant's Sciolto playfully challenges the dictates of patriarchal masculinity by fulfilling them in absurd and unorthodox ways. Ultimately, he illuminates just how untenable those dictates might be.

Efficacy of dendritic cells matured early with OK-432 (Picibanil), prostaglandin E2, and interferon-alpha as a vaccine for a hormone refractory prostate cancer cell line.

PubMed

Yoo, Changhee; Do, Hyun-Ah; Jeong, In Gab; Park, Hongzoo; Hwang, Jung-Jin; Hong, Jun Hyuk; Cho, Jin Seon; Choo, Myong-Soo; Ahn, Hanjong; Kim, Choung-Soo

2010-09-01

Dendritic cells (DCs) are potent antigen-presenting cells. OK432 (Picibanil) was introduced as a potent stimulator of DC maturation in combination with prostaglandin-E(2) and interferon-alpha. We compared the efficacy of a DC-prostate cancer vaccine using early-mature DCs stimulated with OK432, PGE2 and INF-alpha (OPA) with that of vaccines using other methods. On days 3 or 7 of DC culture, TNF-alpha (T), TNF-alpha and LPS (TL) or OPA were employed as maturation stimulators. DU145 cells subjected to heat stress were hybridized with mature DCs using polyethyleneglycol. T cells were sensitized by the hybrids, and their proliferative and cytokine secretion activities and cytotoxicity were measured. The yields of early-mature DCs were higher, compared to yields at the conventional maturation time (P<0.05). In the early maturation setting, the mean fusion ratios, calculated from the fraction of dual-positive cells, were 13.3%, 18.6%, and 39.9%, respectively (P=0.051) in the T only, TL, and OPA-treated groups. The function of cytotoxic T cells, which were sensitized with the hybrids containing DCs matured early with OPA, was superior to that using other methods. The antitumor effects of DC-DU145 hybrids generated with DCs subjected to early maturation with the OPA may be superior to that of the hybrids using conventional maturation methods.

Greater Exposure to Sexual Content in Popular Movies Predicts Earlier Sexual Debut and Increased Sexual Risk Taking

PubMed Central

O’Hara, Ross E.; Gibbons, Frederick X.; Gerrard, Meg; Li, Zhigang; Sargent, James D.

2013-01-01

Early sexual debut is associated with risky sexual behavior and an increased risk of unplanned pregnancy and sexually transmitted infections later in life. The relations among early movie sexual exposure (MSE), sexual debut, and risky sexual behavior in adulthood (i.e., multiple sexual partners and inconsistent condom use) were examined in a longitudinal study of U.S. adolescents. MSE was measured using the Beach method, a comprehensive procedure for media content coding. Controlling for characteristics of adolescents and their families, analyses showed that MSE predicted age of sexual debut, both directly and indirectly through changes in sensation seeking. MSE also predicted engagement in risky sexual behaviors both directly and indirectly via early sexual debut. These results suggest that MSE may promote sexual risk taking both by modifying sexual behavior and by accelerating the normal rise in sensation seeking during adolescence. PMID:22810165

Sexuality (and Lack Thereof) in Adolescence and Early Adulthood: A Review of the Literature

PubMed Central

Boislard, Marie-Aude; van de Bongardt, Daphne; Blais, Martin

2016-01-01

Youth sexuality has been primarily studied with a focus on its potential public health issues, such as sexually transmitted infections and unwanted pregnancies, and its comorbidity with other risky behaviors. More recently, it has been studied as a normative step in romantic partnerships, either pre- or post-marital, as well as outside the context of romantic involvement. In this paper, we review the extensive literature on sexuality in adolescence and early adulthood both within and outside romantic relationships (i.e., casual sexual relationships and experiences; CSREs). Furthermore, the recent recognition of youth sexuality as a developmental task has led to a renewed interest from scholars in youth who abstain from sexual encounters, whether deliberately or not. A brief overview of the literature on cultural differences in sexuality, and sexual-minority youth sexual development is also provided. This paper concludes by suggesting future directions to bring the field of youth sexuality and romantic relationships forward. PMID:26999225

[Sexual maturation of children and adolescents in Germany. Results of the German Health Interview and Examination Survey for Children and Adolescents (KiGGS)].

PubMed

Kahl, H; Schaffrath Rosario, A; Schlaud, M

2007-01-01

Following the standstill in maturity acceleration in the eighties of the twentieth century, now a further shift in maturity development towards younger ages is the issue of an international and also German discussion. The collection of sexual maturity data in boys and girls as part of the nationwide German Health Interview and Examination Survey for Children and Adolescents (KiGGS) is intended to pro vide population-representative information on sexual maturation and to evaluate associations between maturity status and selected health and social data. Girls were interviewed regarding their first menstrual period (menarche) and boys regarding voice change (status-quo method). Pubic hair was self-assessed by children and adolescents from 10 to 17 years of age, based on drawings of Tanner's defined developmental stages. The median age for menarche, for voice change and pubic hair stages were calculated using a logit model. At an age of 10 years, 42.4 % of girls and 35.7 % of boys report the development of pubic hair. At 17 years of age, the majority of girls and boys have reached the stages PH5 (girls 57.5 %, boys 47.8 %) and PH6 (girls 23.6 %, boys 46.5 %) according to Tanner. The average age for each pubic hair stage is lower in girls (PH2 10.8; PH3 11.7; PH4 12.3; PH5 13.4 years) than in boys (PH2 10.9; PH3 12.6; PH4 13.4; PH5 14.1). The median age at menarche is 12.8 years, the median for voice change (voice low) 15.1 years. Significant differences in age at menarche are found in girls depending on socioeconomic status (12.7/12.9/13.0 years for low/middle/high status) and between girls with and without migration background (12.5/12.9 years). No differences in age at menarche can be seen between East and West Germany or cities and rural areas. The association between maturity status and BMI is more pronounced in girls than in boys. Overall, the onset of maturity development in German children and adolescents is not significantly earlier than in other European

Mechanical factors direct mouse aortic remodelling during early maturation

PubMed Central

Le, Victoria P.; Cheng, Jeffrey K.; Kim, Jungsil; Staiculescu, Marius C.; Ficker, Shawn W.; Sheth, Saahil C.; Bhayani, Siddharth A.; Mecham, Robert P.; Yanagisawa, Hiromi; Wagenseil, Jessica E.

2015-01-01

Numerous diseases have been linked to genetic mutations that lead to reduced amounts or disorganization of arterial elastic fibres. Previous work has shown that mice with reduced amounts of elastin (Eln+/−) are able to live a normal lifespan through cardiovascular adaptations, including changes in haemodynamic stresses, arterial geometry and arterial wall mechanics. It is not known if the timeline and presence of these adaptations are consistent in other mouse models of elastic fibre disease, such as those caused by the absence of fibulin-5 expression (Fbln5−/−). Adult Fbln5−/− mice have disorganized elastic fibres, decreased arterial compliance and high blood pressure. We examined mechanical behaviour of the aorta in Fbln5−/− mice through early maturation when the elastic fibres are being assembled. We found that the physiologic circumferential stretch, stress and modulus of Fbln5−/− aorta are maintained near wild-type levels. Constitutive modelling suggests that elastin contributions to the total stress are decreased, whereas collagen contributions are increased. Understanding how collagen fibre structure and mechanics compensate for defective elastic fibres to meet the mechanical requirements of the maturing aorta may help to better understand arterial remodelling in human elastinopathies. PMID:25652465

Family Instability and Early Initiation of Sexual Activity in Western Kenya

PubMed Central

2014-01-01

Epidemiological, economic, and social forces have produced high levels of volatility in family and household structure for young people growing up in sub-Saharan Africa in recent decades. However, scholarship on the family to date has not examined the influence of this family instability on young people’s well-being. The current study employs unique life history calendar data from Western Kenya to investigate the relationship between instability in caregiving and early initiation of sexual activity. It draws on a body of work on parental union instability in the United States, and examines new dimensions of family change. Analyses reveal a positive association between transitions in primary caregiver and the likelihood of early sexual debut that is rapidly manifested following caregiver change and persists for a short period. The association is strongest at early ages, and there is a cumulative effect of multiple caregiver changes. The results highlight the importance of studying family stability in sub-Saharan Africa, as distinct from family structure, and for attention to dimensions such as age and recency. PMID:23055236

Family instability and early initiation of sexual activity in Western Kenya.

PubMed

Goldberg, Rachel E

2013-04-01

Epidemiological, economic, and social forces have produced high levels of volatility in family and household structure for young people growing up in sub-Saharan Africa in recent decades. However, scholarship on the family to date has not examined the influence of this family instability on young people's well-being. The current study employs unique life history calendar data from Western Kenya to investigate the relationship between instability in caregiving and early initiation of sexual activity. It draws on a body of work on parental union instability in the United States, and examines new dimensions of family change. Analyses reveal a positive association between transitions in primary caregiver and the likelihood of early sexual debut that is rapidly manifested following caregiver change and persists for a short period. The association is strongest at early ages, and there is a cumulative effect of multiple caregiver changes. The results highlight the importance of studying family stability in sub-Saharan Africa, as distinct from family structure, and for attention to dimensions such as age and recency.

5-HTTLPR status moderates the effect of early adolescent substance use on risky sexual behavior.

PubMed

Kogan, Steven M; Beach, Steven R H; Philibert, Robert A; Brody, Gene H; Chen, Yi-Fu; Lei, Man-Kit

2010-09-01

A longitudinal, prospective design was used to investigate a moderation effect in the association between early adolescent substance use and risky sexual behavior 2 years later. A genetic vulnerability factor, a variable nucleotide repeat polymorphism (VNTR) in the promoter region of the serotonin transporter gene SLC6A4, known as 5-HTTLPR, was hypothesized to moderate the link between substance use at age 14 and risky sexual behavior at age 16. This VNTR has been associated with risk-taking behavior. African American youths in rural Georgia (N = 185) provided 2 waves of data on their substance use and sexual behavior. Genetic data were obtained via saliva samples. Substance use and sexual risk behavior were assessed using youth self-report items developed for this investigation. Multiple regression analyses indicated that the presence of 1 or 2 copies of the short allele of the VNTR interacted with substance use to predict sexual behavior. Substance use had little effect on sexual behavior for youths without the short allele; this effect was greatly increased for youths with the short allele. Genetic vulnerability affected the implications of early onset substance use for later sexual behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved).

Are coping styles consistent in the teleost fish Sparus aurata through sexual maturation and sex reversal?

PubMed

Castanheira, Maria Filipa; Martínez Páramo, Sonia; Figueiredo, F; Cerqueira, Marco; Millot, Sandie; Oliveira, Catarina C V; Martins, Catarina I M; Conceição, Luís E C

2016-10-01

Individual differences in behaviour and physiological responses to stress are associated with evolutionary adaptive variation and thus raw material for evolution. In farmed animals, the interest in consistent trait associations, i.e. coping styles, has increased dramatically over the last years. However, one of limitations of the available knowledge, regarding the temporal consistency, is that it refers always to short-term consistency (usually few weeks). The present study used an escape response during a net restraining test, previously shown to be an indicative of coping styles in seabream, to investigate long-term consistency of coping styles both over time and during different life history stages. Results showed both short-term (14 days) consistency and long-term (8 months) consistency of escape response. However, we did not found consistency in the same behaviour after sexual maturation when the restraining test was repeated 16, 22 and 23 months after the first test was performed. In conclusion, this study showed consistent behaviour traits in seabream when juveniles, and a loss of this behavioural traits when adults. Therefore, these results underline that adding a life story approach to data interpretation as an essential step forward towards coping styles foreground. Furthermore, a fine-tuning of aquaculture rearing strategies to adapt to different coping strategies may need to be adjusted differently at early stages of development and adults to improve the welfare of farmed fish.

Efficacy of Dendritic Cells Matured Early with OK-432 (Picibanil®), Prostaglandin E2, and Interferon-α as a Vaccine for a Hormone Refractory Prostate Cancer Cell Line

PubMed Central

Yoo, Changhee; Do, Hyun-Ah; Jeong, In Gab; Park, Hongzoo; Hwang, Jung-Jin; Hong, Jun Hyuk; Cho, Jin Seon; Choo, Myong-Soo; Ahn, Hanjong

2010-01-01

Dendritic cells (DCs) are potent antigen-presenting cells. OK432 (Picibanil®) was introduced as a potent stimulator of DC maturation in combination with prostaglandin-E2 and interferon-α. We compared the efficacy of a DC-prostate cancer vaccine using early-mature DCs stimulated with OK432, PGE2 and INF-α (OPA) with that of vaccines using other methods. On days 3 or 7 of DC culture, TNF-α (T), TNF-α and LPS (TL) or OPA were employed as maturation stimulators. DU145 cells subjected to heat stress were hybridized with mature DCs using polyethyleneglycol. T cells were sensitized by the hybrids, and their proliferative and cytokine secretion activities and cytotoxicity were measured. The yields of early-mature DCs were higher, compared to yields at the conventional maturation time (P<0.05). In the early maturation setting, the mean fusion ratios, calculated from the fraction of dual-positive cells, were 13.3%, 18.6%, and 39.9%, respectively (P=0.051) in the T only, TL, and OPA-treated groups. The function of cytotoxic T cells, which were sensitized with the hybrids containing DCs matured early with OPA, was superior to that using other methods. The antitumor effects of DC-DU145 hybrids generated with DCs subjected to early maturation with the OPA may be superior to that of the hybrids using conventional maturation methods. PMID:20808670

Revisiting the association between pornography use and risky sexual behaviors: the role of early exposure to pornography and sexual sensation seeking.

PubMed

Sinković, Matija; Stulhofer, Aleksandar; Božić, Jasmina

2013-01-01

Among the suggested problems and harms associated with widespread pornography use among young people, risky sexual behaviors have been frequently mentioned. To further explore this public health concern, this article analyzed sexual sensation seeking (SSS) as a potential confounder of the association between pornography use and sexual risks using data collected in 2010 from a population-based sample of young Croatian adults aged 18 to 25 (n = 1,005). Significant, but small, correlations were found between the indicators of pornography use (age at first exposure, frequency of use in the past 12 months, and personal importance of pornography) and sexual risk taking. However, in a multivariate analysis, only age at first exposure to pornography remained a significant, albeit weak, predictor of sexual risk taking among both women and men. SSS, defined as the dispositional tendency toward the impulsive pursuit of sexual arousal and stimulation, neither confounded nor moderated this association. Overall, the findings do not support the notion that pornography use is substantially associated with sexual risk taking among young adults, but suggest that early exposure to sexually explicit material and high SSS are additive risk factors for sexual risk taking.

Early life stress accelerates behavioral and neural maturation of the hippocampus in male mice.

PubMed

Bath, K; Manzano-Nieves, G; Goodwill, H

2016-06-01

Early life stress (ELS) increases the risk for later cognitive and emotional dysfunction. ELS is known to truncate neural development through effects on suppressing cell birth, increasing cell death, and altering neuronal morphology, effects that have been associated with behavioral profiles indicative of precocious maturation. However, how earlier silencing of growth drives accelerated behavioral maturation has remained puzzling. Here, we test the novel hypothesis that, ELS drives a switch from growth to maturation to accelerate neural and behavioral development. To test this, we used a mouse model of ELS, fragmented maternal care, and a cross-sectional dense sampling approach focusing on hippocampus and measured effects of ELS on the ontogeny of behavioral development and biomarkers of neural maturation. Consistent with previous work, ELS was associated with an earlier developmental decline in expression of markers of cell proliferation (Ki-67) and differentiation (doublecortin). However, ELS also led to a precocious arrival of Parvalbumin-positive cells, led to an earlier switch in NMDA receptor subunit expression (marker of synaptic maturity), and was associated with an earlier rise in myelin basic protein expression (key component of the myelin sheath). In addition, in a contextual fear-conditioning task, ELS accelerated the timed developmental suppression of contextual fear. Together, these data provide support for the hypothesis that ELS serves to switch neurodevelopment from processes of growth to maturation and promotes accelerated development of some forms of emotional learning. Copyright © 2016 Elsevier Inc. All rights reserved.

Disproportionate Exposure to Early-Life Adversity and Sexual Orientation Disparities in Psychiatric Morbidity

ERIC Educational Resources Information Center

McLaughlin, Katie A.; Hatzenbuehler, Mark L.; Xuan, Ziming; Conron, Kerith J.

2012-01-01

Objectives: Lesbian, gay, and bisexual (LGB) populations exhibit elevated rates of psychiatric disorders compared to heterosexuals, and these disparities emerge early in the life course. We examined the role of exposure to early-life victimization and adversity--including physical and sexual abuse, homelessness, and intimate partner violence--in…

Growth, size and age at maturity of the agile frog (Rana dalmatina) in an Iberian Peninsula population.

PubMed

Sarasola-Puente, Vanessa; Gosá, Alberto; Oromí, Neus; Madeira, María José; Lizana, Miguel

2011-06-01

The mean age of a population of agile frogs (Rana dalmatina) from the Iberian Peninsula was estimated using mark and recapture and skeletochronology. Life-history parameters, including growth rate, body length, age and size at maturity, sexual dimorphism and longevity, were studied. The regression between age and snout-vent length (SVL) was highly significant in both sexes. Males reached sexual maturity at two years of age, although sometimes they can reach it at only one year of age. The average SVL at maturity was 51.75 mm (standard error (SE)=0.71; n=45). Females reached sexual maturity at two years of age with an average SVL of 62.14 mm (SE=2.20; n=14). A subset of the female population reached sexual maturity at three years of age. Growth was rapid until sexual maturity was reached. There was an overlap of SVL between different age classes. Growth was continuous, fulfilling the conditions of Von Bertalanffy's model. The growth coefficient (K) was 0.840 in males and 0.625 in females. The maximum SVL was greater in females (73.00 mm) than in males (59.50mm). Sexual dimorphism was significantly biased towards females in all age classes. The maximum longevity observed was 6 years in females and 8 years in males. Management strategies for agile frogs should take into account factors such as these life-history characteristics. Copyright © 2011 Elsevier GmbH. All rights reserved.

Child Sexual Abuse in Early-Childhood Care and Education Settings

ERIC Educational Resources Information Center

Briggs, Freda

2014-01-01

When the author was adviser to the Australian Minister for Education for writing the national Safe Schools Framework (2003), meetings were held with early-childhood care and education administrators from all state, Catholic and independent sectors. Their unexpected message was that educators were facing new problems, those of child sexual abuse in…

Longitudinal Examination of the Bullying-Sexual Violence Pathway across Early to Late Adolescence: Implicating Homophobic Name-Calling.

PubMed

Espelage, Dorothy L; Basile, Kathleen C; Leemis, Ruth W; Hipp, Tracy N; Davis, Jordan P

2018-03-02

The Bully-Sexual Violence Pathway theory has indicated that bullying perpetration predicts sexual violence perpetration among males and females over time in middle school, and that homophobic name-calling perpetration moderates that association among males. In this study, the Bully-Sexual Violence Pathway theory was tested across early to late adolescence. Participants included 3549 students from four Midwestern middle schools and six high schools. Surveys were administered across six time points from Spring 2008 to Spring 2013. At baseline, the sample was 32.2% White, 46.2% African American, 5.4% Hispanic, and 10.2% other. The sample was 50.2% female. The findings reveal that late middle school homophobic name-calling perpetration increased the odds of perpetrating sexual violence in high school among early middle school bullying male and female perpetrators, while homophobic name-calling victimization decreased the odds of high school sexual violence perpetration among females. The prevention of bullying and homophobic name-calling in middle school may prevent later sexual violence perpetration.

Human face processing is tuned to sexual age preferences

PubMed Central

Ponseti, J.; Granert, O.; van Eimeren, T.; Jansen, O.; Wolff, S.; Beier, K.; Deuschl, G.; Bosinski, H.; Siebner, H.

2014-01-01

Human faces can motivate nurturing behaviour or sexual behaviour when adults see a child or an adult face, respectively. This suggests that face processing is tuned to detecting age cues of sexual maturity to stimulate the appropriate reproductive behaviour: either caretaking or mating. In paedophilia, sexual attraction is directed to sexually immature children. Therefore, we hypothesized that brain networks that normally are tuned to mature faces of the preferred gender show an abnormal tuning to sexual immature faces in paedophilia. Here, we use functional magnetic resonance imaging (fMRI) to test directly for the existence of a network which is tuned to face cues of sexual maturity. During fMRI, participants sexually attracted to either adults or children were exposed to various face images. In individuals attracted to adults, adult faces activated several brain regions significantly more than child faces. These brain regions comprised areas known to be implicated in face processing, and sexual processing, including occipital areas, the ventrolateral prefrontal cortex and, subcortically, the putamen and nucleus caudatus. The same regions were activated in paedophiles, but with a reversed preferential response pattern. PMID:24850896

Human face processing is tuned to sexual age preferences.

PubMed

Ponseti, J; Granert, O; van Eimeren, T; Jansen, O; Wolff, S; Beier, K; Deuschl, G; Bosinski, H; Siebner, H

2014-05-01

Human faces can motivate nurturing behaviour or sexual behaviour when adults see a child or an adult face, respectively. This suggests that face processing is tuned to detecting age cues of sexual maturity to stimulate the appropriate reproductive behaviour: either caretaking or mating. In paedophilia, sexual attraction is directed to sexually immature children. Therefore, we hypothesized that brain networks that normally are tuned to mature faces of the preferred gender show an abnormal tuning to sexual immature faces in paedophilia. Here, we use functional magnetic resonance imaging (fMRI) to test directly for the existence of a network which is tuned to face cues of sexual maturity. During fMRI, participants sexually attracted to either adults or children were exposed to various face images. In individuals attracted to adults, adult faces activated several brain regions significantly more than child faces. These brain regions comprised areas known to be implicated in face processing, and sexual processing, including occipital areas, the ventrolateral prefrontal cortex and, subcortically, the putamen and nucleus caudatus. The same regions were activated in paedophiles, but with a reversed preferential response pattern. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Early life sexual abuse is associated with increased suicide attempts: An update meta-analysis.

PubMed

Ng, Qin Xiang; Yong, Bob Zheng Jie; Ho, Collin Yin Xian; Lim, Donovan Yutong; Yeo, Wee-Song

2018-04-01

Suicide is an emerging, yet preventable global health issue associated with significant mortality. Identification of underlying risk factors and antecedents may inform preventive strategies and interventions. This study serves to provide an updated meta-analysis examining the extent of association of early life sexual abuse with suicide attempts. Using the keywords [early abuse OR childhood abuse OR sexual OR rape OR molest* OR violence OR trauma OR PTSD] AND [suicid* OR premature OR unnatural OR deceased OR died OR mortality], a preliminary search on the PubMed, Ovid, PsychINFO, Web of Science and Google Scholar databases yielded 12,874 papers published in English between 1-Jan-1988 and 1-June-2017. Of these, only 47 studies were included in the final meta-analysis. The 47 studies (25 cross-sectional, 14 cohort, 6 case-control and 2 twin studies) contained a total of 151,476 subjects. Random-effects meta-analysis found early life sexual abuse to be a significant risk factor for suicide attempts, compared to baseline population (pooled OR 1.89, 95% CI: 1.66 to 2.12, p < 0.001). Subgroup analyses of cross-sectional and longitudinal studies showed similar findings of increased risk as they yielded ORs of 1.98 (95% CI: 1.70 to 2.25, p < 0.001) and 1.65 (95% CI: 1.37 to 1.93, p < 0.001), respectively. In both cross-sectional and longitudinal studies, childhood sexual abuse was consistently associated with increased risk of suicide attempts. The findings of the present study provide strong grounds for funding public policy planning and interventions to prevent sexual abuse and support its victims. Areas for future research should include preventive and treatment strategies and factors promoting resilience following childhood sexual abuse. Future research on the subject should have more robust controls and explore the differential effects of gender and intra-versus extra-familial sexual abuse. Copyright © 2018 Elsevier Ltd. All rights reserved.

High-density genetic linkage map construction by F2 populations and QTL analysis of early-maturity traits in upland cotton (Gossypium hirsutum L.).

PubMed

Li, Libei; Zhao, Shuqi; Su, Junji; Fan, Shuli; Pang, Chaoyou; Wei, Hengling; Wang, Hantao; Gu, Lijiao; Zhang, Chi; Liu, Guoyuan; Yu, Dingwei; Liu, Qibao; Zhang, Xianlong; Yu, Shuxun

2017-01-01

Due to China's rapidly increasing population, the total arable land area has dramatically decreased; as a consequence, the competition for farming land allocated for grain and cotton production has become fierce. Therefore, to overcome the existing contradiction between cotton grain and fiber production and the limited farming land, development of early-maturing cultivars is necessary. In this research, a high-density linkage map of upland cotton was constructed using genotyping by sequencing (GBS) to discover single nucleotide polymorphism (SNP) markers associated with early maturity in 170 F2 individuals derived from a cross between LU28 and ZHONG213. The high-density genetic map, which was composed of 3978 SNP markers across the 26 cotton chromosomes, spanned 2480 cM with an average genetic distance of 0.62 cM. Collinearity analysis showed that the genetic map was of high quality and accurate and agreed well with the Gossypium hirsutum reference genome. Based on this high-density linkage map, QTL analysis was performed on cotton early-maturity traits, including FT, FBP, WGP, NFFB, HNFFB and PH. A total 47 QTLs for the six traits were detected; each of these QTLs explained between 2.61% and 32.57% of the observed phenotypic variation. A major region controlling early-maturity traits in Gossypium hirsutum was identified for FT, FBP, WGP, NFFB and HNFFB on chromosome D03. QTL analyses revealed that phenotypic variation explained (PVE) ranged from 10.42% to 32.57%. Two potential candidate genes, Gh_D03G0885 and Gh_D03G0922, were predicted in a stable QTL region and had higher expression levels in the early-maturity variety ZHONG213 than in the late-maturity variety LU28. However, further evidence is required for functional validation. This study could provide useful information for the dissection of early-maturity traits and guide valuable genetic loci for molecular-assisted selection (MAS) in cotton breeding.

High-density genetic linkage map construction by F2 populations and QTL analysis of early-maturity traits in upland cotton (Gossypium hirsutum L.)

PubMed Central

Li, Libei; Zhao, Shuqi; Su, Junji; Fan, Shuli; Pang, Chaoyou; Wei, Hengling; Wang, Hantao; Gu, Lijiao; Zhang, Chi; Liu, Guoyuan; Yu, Dingwei; Liu, Qibao; Zhang, Xianlong

2017-01-01

Due to China’s rapidly increasing population, the total arable land area has dramatically decreased; as a consequence, the competition for farming land allocated for grain and cotton production has become fierce. Therefore, to overcome the existing contradiction between cotton grain and fiber production and the limited farming land, development of early-maturing cultivars is necessary. In this research, a high-density linkage map of upland cotton was constructed using genotyping by sequencing (GBS) to discover single nucleotide polymorphism (SNP) markers associated with early maturity in 170 F2 individuals derived from a cross between LU28 and ZHONG213. The high-density genetic map, which was composed of 3978 SNP markers across the 26 cotton chromosomes, spanned 2480 cM with an average genetic distance of 0.62 cM. Collinearity analysis showed that the genetic map was of high quality and accurate and agreed well with the Gossypium hirsutum reference genome. Based on this high-density linkage map, QTL analysis was performed on cotton early-maturity traits, including FT, FBP, WGP, NFFB, HNFFB and PH. A total 47 QTLs for the six traits were detected; each of these QTLs explained between 2.61% and 32.57% of the observed phenotypic variation. A major region controlling early-maturity traits in Gossypium hirsutum was identified for FT, FBP, WGP, NFFB and HNFFB on chromosome D03. QTL analyses revealed that phenotypic variation explained (PVE) ranged from 10.42% to 32.57%. Two potential candidate genes, Gh_D03G0885 and Gh_D03G0922, were predicted in a stable QTL region and had higher expression levels in the early-maturity variety ZHONG213 than in the late-maturity variety LU28. However, further evidence is required for functional validation. This study could provide useful information for the dissection of early-maturity traits and guide valuable genetic loci for molecular-assisted selection (MAS) in cotton breeding. PMID:28809947

Slab replacement maturity guidelines.

DOT National Transportation Integrated Search

2014-04-01

This study investigated the use of maturity method to determine early age strength of concrete in slab : replacement application. Specific objectives were (1) to evaluate effects of various factors on the compressive : maturity-strength relationship ...

Adolescent females with a substance use disorder: affiliations with adult male sexual partners.

PubMed

Castillo Mezzich, A; Giancola, P R; Lu, S Y; Parks, S M; Ratica, G M; Dunn, M

1999-01-01

To test the hypothesis that low socioeconomic status (SES), a disturbed parent-daughter relationship, early sexual development, and antisocial behavior are risk factors in adolescent females affiliating with adult male sexual partners. To determine whether the relation between these risk factors and affiliating with adult male sexual partners is stronger in females with greater, rather than fewer, substance use disorders (SUD). Subjects were 180 adolescent females with SUD and 87 normal controls (14-18 years of age). The SUD group had a lower SES and more negative parent-daughter interactions, and exhibited greater antisocial tendencies. Also, the SUD group showed a more frequent affiliation with adult male sexual partners. Chronological age, age of menarche (sexual development), antisocial behavior, and quality of the parent-daughter relationship were significantly associated with affiliation with adult male sexual partners. Moreover, the number of SUD diagnoses enhanced the relation between the quality of the parent-daughter relationship and antisocial behavior with affiliation with adult male sexual partners. From a prevention perspective, interventions directed at enhancing child rearing practices, communication skills, and involvement in children's needs and activities might result in improved parent-child attachments that may attentuate young women's propensities to become involved in antisocial behavior and affiliate with adult sexual partners. Also, the risk imposed by an early sexual maturation may be offset by enhancing the female adolescent's social skills to select non-deviant and supportive male partners.

[Sex education and the problem of early sexual relations among adolescents].

PubMed

Castellanous Simons, B; Gonzalez Hernandez, A

1981-01-01

Puberty today occurs about 2 years earlier than it did at the beginning of the century. The age of menarche is now usually between 11-13 years, while the establishment of spermatogenesis and appearance of the 1st ejaculation usually occurs between 13-15 years. The ages at which adolescents feel mature, want to behave like adults, and initiate sexual activity are now lower than in the past. Sexual relations may occur between adolescents before they are fully capable of recognizing their consequences as autonomous and responsible acts guided by a system of moral convictions. Both marriage and parenthood may have unfavorable consequences for future personality development, sexual adjustment, and the personal-social adaptation of the individual. In Cuba, the persistence of traces of bourgeois mentality can be seen in the tendency to teach young girls false concepts of female behavior. Traits such as submissiveness, passivity, and fragility are stressed, and girls are taught to inhibit their sexuality from a very young age. Adolescent boys are expected to display virility and machismo. Adolescent boys may be so interested in the physical aspects of sexual activity that they deprecate the aspects, considering them to be weak female traits. Boys are more likely to separate the sexual object and the love object, while such duality is unusual in girls. Among the most serious problems of adolescent sexual activity in Cuba is a high rate of abortions among young adolescents. Some adolescents are promiscuous and have frequent changes of partner. The age group 15-19 years has the 3rd highest rate of syphilis and the 2nd highest of gonorrhea. The proportion of births to minors has increased from 22% in 1973 to almost half in some provinces. Divorce rates have been in constant increase in Cuba, and psychosocial immaturity of very young spouses is a principal factor in divorce. The widening temporal gap between attainment of puberty and marriage, which is likely to be postponed

Early constraints in sexual dimorphism: survival benefits of feminized phenotypes.

PubMed

López-Rull, I; Vergara, P; Martínez-Padilla, J; Fargallo, J A

2016-02-01

Sexual dimorphism (SD) has evolved in response to selection pressures that differ between sexes. Since such pressures change across an individual's life, SD may vary within age classes. Yet, little is known about how selection on early phenotypes may drive the final SD observed in adults. In many dimorphic species, juveniles resemble adult females rather than adult males, meaning that out of the selective pressures established by sexual selection feminized phenotypes may be adaptive. If true, fitness benefits of early female-like phenotypes may constrain the expression of male phenotypes in adulthood. Using the common kestrel Falco tinnunculus as a study model, we evaluated the fitness advantages of expressing more feminized phenotypes at youth. Although more similar to adult females than to adult males, common kestrel fledglings are still sexually dimorphic in size and coloration. Integrating morphological and chromatic variables, we analysed the phenotypic divergence between sexes as a measure of how much each individual looks like the sex to which it belongs (phenotypic sexual resemblance, PSR). We then tested the fitness benefits associated with PSR by means of the probability of recruitment in the population. We found a significant interaction between PSR and sex, showing that in both sexes more feminized phenotypes recruited more into the population than less feminized phenotypes. Moreover, males showed lower PSR than females and a higher proportion of incorrect sex classifications. These findings suggest that the mechanisms in males devoted to resembling female phenotypes in youth, due to a trend to increase fitness through more feminized phenotypes, may provide a mechanism to constrain the SD in adulthood. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

Sexual communication between early adolescents and their dating partners, parents, and best friends.

PubMed

Widman, Laura; Choukas-Bradley, Sophia; Helms, Sarah W; Golin, Carol E; Prinstein, Mitchell J

2014-01-01

This study assessed early adolescents' sexual communication with dating partners, parents, and best friends about six sexual health topics: condoms, birth control, sexually transmitted diseases (STDs), human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS), pregnancy, and abstinence/waiting. Using a school-based sample of 603 youth (ages 12 to 15; 57% female; 46% Caucasian), we examined communication differences across demographic and developmental factors, tested whether communication with parents and best friends was associated with greater communication with partners, and examined associations between communication and condom use. More than half of participants had not discussed any sexual topics with their dating partners (54%), and many had not communicated with parents (29%) or best friends (25%). On average, communication was more frequent among adolescents who were female, African American, older, and sexually active, despite some variation in subgroups across partner, parent, and friend communication. Importantly, communication with parents and friends--and the interaction between parent and friend communication--was associated with increased communication with dating partners. Further, among sexually active youth, increased sexual communication with partners was associated with more frequent condom use. Results highlight the importance of understanding the broader family and peer context surrounding adolescent sexual decision making and suggest a possible need to tailor sexual communication interventions.

Gender differences? Internet use and parent-child communication about sex toward sexual attitudes among early adolescents in Taiwan.

PubMed

Tseng, Ying-Hua; Weng, Chia-Sui; Kuo, Shih-Hsien; Chou, Fan-Hao; Yang, Yi-Hsin; Chiang, Li-Chi

2015-06-01

With the progress of information technology, early adolescents are able to access sex-related information through the Internet easily. This information has been shown to have a significant influence on the sexual health of this population. In addition, parent-child communications about sex affect the sexual health of adolescents. Few empirical studies have focused on early adolescents and gender differences. This study explores gender differences between early adolescents in terms of the use of the Internet to obtain sex-related information, parent-child communication, and sex-related knowledge and attitudes. This cross-sectional and comparative study uses an analysis of covariance and a hierarchical regression for data analysis. The researchers recruited 457 sixth-grade boys (n = 204) and girls (n = 253) in southern Taiwan as participants and used a structured questionnaire to collect data. Participants exhibited significant differences in terms of Internet usage behavior, parent-child communications about sex, and sex-related knowledge and sexual attitudes. The male participants spent more time on "recreation and entertainment" activities on the Internet, whereas their female peers spent significantly more time searching for information. Regarding parent-child communications about sex, girls had better mother-child communications than boys. In addition, no gender-based difference was found for father-child communications about sex. The knowledge of physical changes occurring during puberty and of menstrual healthcare among female participants was superior to their male counterparts. Girls had a more informed sexual attitude, particularly with regard to issues of gender roles, relationships with the opposite gender, and the social aspects of sex. Sex-related knowledge and parent-child communication about sex were the two major predictors of sexual attitudes for boys and girls, respectively. To develop healthy sexual attitudes among early adolescents, nursing

The influence of primary caregivers on the sexual behavior of early adolescents.

PubMed

Rose, Allison; Koo, Helen P; Bhaskar, Brinda; Anderson, Karen; White, Gregory; Jenkins, Renee R

2005-08-01

To describe rates of sexual intercourse initiation, anticipated level of sexual activity in the next 12 months, and other risk behaviors among fifth graders and to examine parental factors associated with such behaviors. This study is based on a cross-sectional, self-administered survey conducted with a nonrandom sample of 408 fifth graders and their caregivers. Children answered questions regarding sexual intercourse initiation, anticipated sexual activity in the next 12 months, and involvement in other risk behaviors. Caregivers answered questions about parenting factors such as monitoring behaviors, parent-child relationship quality, and parent-child communication. Bivariate and multivariable analyses examined the association of these variables with the adolescents' behaviors. Almost 5% of girls and 17% of boys reported they had engaged in sexual intercourse. Only 34% of girls and 13% of boys said they did not expect to engage in any type of sexual contact in the next 12 months if they were going with someone they "liked a lot." Parental factors associated with fewer risk behaviors and expected sexual behaviors included higher levels of monitoring, fewer communication barriers, less permissive attitudes regarding adolescent sexual behavior, higher relationship quality with child, having fewer than five children in the household, higher levels of education, and being employed. Significant gender interactions were found for several variables. Adolescents are initiating sexual intercourse at extremely young ages. To delay early sexual activity and prevent adolescent pregnancy, prevention efforts must begin during the elementary school years and include those who raise and care for the adolescent.

Impact of phthalate and BPA exposure during in utero windows of susceptibility on reproductive hormones and sexual maturation in peripubertal males.

PubMed

Watkins, Deborah J; Sánchez, Brisa N; Téllez-Rojo, Martha Maria; Lee, Joyce M; Mercado-García, Adriana; Blank-Goldenberg, Clara; Peterson, Karen E; Meeker, John D

2017-06-21

Phthalates and BPA are endocrine disrupting chemicals (EDCs) widely used in consumer products. Evidence suggests that phthalate and BPA exposure alters steroid hormone levels in adults, while in utero exposure has been associated with altered fetal reproductive development in boys. However, the impact of exposure during distinct critical windows of in utero development on hormone concentrations and sexual maturation during the pubertal transition has not been examined. The objective of this study was to assess trimester-specific in utero phthalate and BPA exposure in relation to measures of reproductive development among peripubertal boys in a Mexico City birth cohort. We measured maternal urinary phthalate metabolites and BPA during the first, second, and third trimesters of pregnancy. We measured serum levels of testosterone, estradiol, dehydroepiandrosterone sulfate (DHEA-S), inhibin B, and sex hormone-binding globulin (SHBG), and assessed sexual maturation (Tanner staging and testicular volume) among male children at age 8-14 years (n = 109). Linear and logistic regression were used to investigate trimester-specific in utero exposure as predictors of peripubertal hormone levels and sexual maturation, respectively. In sensitivity analyses we evaluated estimated exposure at 7 weeks gestation and rates of change in exposure across pregnancy in relation to outcomes. Exposure to phthalates during the third trimester was associated with reduced odds of having a Tanner stage >1 for pubic hair development (e.g. MBzP OR = 0.18 per interquartile range (IQR) increase; 95% CI:0.03-0.97) and higher peripubertal SHBG levels (e.g. MBzP 15.2%/IQR; 95% CI:3.2-28%), while first and second trimester phthalates were not. In contrast, exposure to DEHP during the first trimester was associated with higher estradiol (11%/IQR; 95% CI:1.5-22%), while second or third trimester DEHP exposure was not. Sensitivity analyses yielded similar findings. Associations between in utero

Sexually Dimorphic Responses to Early Adversity: Implications for Affective Problems and Autism Spectrum Disorder

PubMed Central

Davis, Elysia Poggi; Pfaff, Donald

2014-01-01

During gestation, development proceeds at a pace that is unmatched by any other stage of the lifecycle. For these reason the human fetus is particularly susceptible not only to organizing influences, but also to pathogenic disorganizing influences. Growing evidence suggests that exposure to prenatal adversity leads to neurological changes that underlie lifetime risks for mental illness. Beginning early in gestation, males and females show differential developmental trajectories and responses to stress. It is likely that sex-dependent organization of neural circuits during the fetal period influences differential vulnerability to mental health problems. We consider in this review evidence that sexually dimorphic responses to early life stress are linked to two developmental disorders: affective problems (greater female prevalence) and autism spectrum disorder (greater male prevalence). Recent prospective studies illustrating the neurodevelopmental consequences of fetal exposure to stress and stress hormones for males and females are considered here. Plausible biological mechanisms including the role of the sexually differentiated placenta are discussed. We consider in this review evidence that sexually dimorphic responses to early life stress are linked to two sets of developmental disorders: affective problems (greater female prevalence) and autism spectrum disorders (greater male prevalence). PMID:25038479

Feeding habits, sexual dimorphism and size at maturity of the lizard Cnemidophorus ocellifer (Spix, 1825) (Teiidae) in a reforested restinga habitat in northeastern Brazil.

PubMed

Santana, G G; Vasconcellos, A; Gadelha, Y E A; Vieira, W L S; Almeida, W O; Nóbrega, R P; Alves, R R N

2010-05-01

The feeding habits, the sexual dimorphism in size and sexual maturity of the actively foraging lizard Cnemidophorusocellifer were analysed in an area of a reforested Restinga habitat located in the municipality of Mataraca, along the northern-most coast of Paraíba State, Brazil. Seventy-five specimens of C. ocellifer were examined (46 males and 29A females). Of this total, only 23 specimens had prey in their stomachs. The most frequent prey consumed items were orthopterans (50%), coleopterans (23.9%) and arachnids (10.9%); termites and insect larvae were less consumed (both with 2.2%). There were no significant differences observed between the numbers of prey consumed by either males or females. There were significant differences in SVL (snout-vent length) between the sexes, with males attaining larger SVL values. When the influence of SVL was removed from the analyses, sexual dimorphism in the form was still reflected in the head size of these lizards. Sexual maturity in females and males was attained with SVL of 42.2 and 49.0 mm respectively. Although no significant difference was observed between the SVL of the females and the number of eggs produced, there was a clear tendency for larger females to produce more eggs. The low structural complexity of the vegetation and the poor soil quality in the reforested restinga area examined does not furnish favourable habitat for insect and termite larvae, contributing to the marked differences in the diet of the population of C. ocellifer observed in the present study in relation to the diet of their conspecifics in undisturbed areas of restinga, cerrado and caatinga.

The maturity index as a tool to facilitate the interpretation of changes in vitellogenin production and sex ratio in the Fish Sexual Development Test.

PubMed

Baumann, Lisa; Holbech, Henrik; Keiter, Susanne; Kinnberg, Karin Lund; Knörr, Susanne; Nagel, Tina; Braunbeck, Thomas

2013-03-15

In July 2011, the Fish Sexual Development Test (FSDT) has officially been adopted as OECD test guideline 234 for the detection of endocrine disrupting chemicals (EDCs). Sex ratio and vitellogenin (VTG) induction are the mandatory endocrine endpoints within this test, whereas gonad staging is only included as an option. In the present study, five FSDTs with zebrafish (Danio rerio) were conducted with EDCs with different modes of action (17α-ethinylestradiol, dihydrotestosterone, 17β-trenbolone, prochloraz and 4-tert-pentylphenol). Results document that not only sex ratio and VTG production of the exposed fish were massively affected, but also gonad maturation. As a novel approach for the quantification of gonad maturation in zebrafish, the maturity index was developed to allow not only an improved assessment of dose-dependent EDC-related effects on gonad maturation, but also statistical analysis of histological data. VTG induction and maturity index showed an excellent correlation for all five EDCs tested. Most importantly, the maturity index often helped to find appropriate interpretations for results that seemed contradictory at first sight. Results show that histological analyses and their predictive power for population fitness are currently underestimated and should become a standard component in the evaluation of potential EDCs. Copyright © 2012 Elsevier B.V. All rights reserved.

Individual, Familial, Friends-Related and Contextual Predictors of Early Sexual Intercourse

ERIC Educational Resources Information Center

Boislard P., Marie-Aude; Poulin, Francois

2011-01-01

This study examined the unique and simultaneous contribution of adolescents' characteristics, parent-child relationship and friends' characteristics on early sexual intercourse, while accounting for family status. A longitudinal multi-sample design was used. The first sample was recruited in a suburban context (n = 265; 62% girls) and the second…

Differential maturation of rhythmic clock gene expression during early development in medaka (Oryzias latipes).

PubMed

Cuesta, Ines H; Lahiri, Kajori; Lopez-Olmeda, Jose Fernando; Loosli, Felix; Foulkes, Nicholas S; Vallone, Daniela

2014-05-01

One key challenge for the field of chronobiology is to identify how circadian clock function emerges during early embryonic development. Teleosts such as the zebrafish are ideal models for studying circadian clock ontogeny since the entire process of development occurs ex utero in an optically transparent chorion. Medaka (Oryzias latipes) represents another powerful fish model for exploring early clock function with, like the zebrafish, many tools available for detailed genetic analysis. However, to date there have been no reports documenting circadian clock gene expression during medaka development. Here we have characterized the expression of key clock genes in various developmental stages and in adult tissues of medaka. As previously reported for other fish, light dark cycles are required for the emergence of clock gene expression rhythms in this species. While rhythmic expression of per and cry genes is detected very early during development and seems to be light driven, rhythmic clock and bmal expression appears much later around hatching time. Furthermore, the maturation of clock function seems to correlate with the appearance of rhythmic expression of these positive elements of the clock feedback loop. By accelerating development through elevated temperatures or by artificially removing the chorion, we show an earlier onset of rhythmicity in clock and bmal expression. Thus, differential maturation of key elements of the medaka clock mechanism depends on the developmental stage and the presence of the chorion.

Sexual Narcissism and Infidelity in Early Marriage

PubMed Central

McNulty, James K.; Widman, Laura

2014-01-01

There is theoretical reason to believe that narcissism is associated with infidelity. Yet, studies that have examined this association have yielded inconsistent results. Given that these inconsistencies may have emerged because prior studies used global assessments of narcissism that do not capture the extent to which the components of narcissism are activated in the sexual domain, the current research drew from two longitudinal studies of 123 married couples to examine the extent to which sexual narcissism predicted marital infidelity. Consistent with the idea that narcissism predicts sexual behavior when activated in the sexual domain, own sexual narcissism was positively associated with infidelity, controlling for own marital and sexual satisfaction, own globally-assessed narcissism, partner globally-assessed narcissism, and partner sexual narcissism. Helping to explain why this association emerged, further analyses demonstrated that it was driven by all four facets of sexual narcissism—sexual exploitation, grandiose sense of sexual skill, sexual entitlement (Study 1 only), and lack of sexual empathy (husbands only). Additionally, although partner sexual narcissism was unrelated to infidelity on average, partners’ grandiose sense of sexual skill and partners’ sexual entitlement (Study 2 only) were positively associated with infidelity, and partners’ lack of sexual empathy was negatively associated with infidelity (Study 2 only). These findings highlight the benefits of using domain-specific measures of sexual narcissism in research on sexual behavior and the benefits of using domain-specific measures of personality more generally. PMID:24696386

Sexual narcissism and infidelity in early marriage.

PubMed

McNulty, James K; Widman, Laura

2014-10-01

There is theoretical reason to believe that narcissism is associated with infidelity. Yet, studies that have examined this association have yielded inconsistent results. Given that these inconsistencies may have emerged because prior studies used global assessments of narcissism that do not capture the extent to which the components of narcissism are activated in the sexual domain, the current research drew from two longitudinal studies of 123 married couples to examine the extent to which sexual narcissism predicted marital infidelity. Consistent with the idea that narcissism predicts sexual behavior when activated in the sexual domain, own sexual narcissism was positively associated with infidelity, controlling for own marital and sexual satisfaction, own globally-assessed narcissism, partner globally-assessed narcissism, and partner sexual narcissism. Helping to explain why this association emerged, further analyses demonstrated that it was driven by all four facets of sexual narcissism-sexual exploitation, grandiose sense of sexual skill, sexual entitlement (Study 1 only), and lack of sexual empathy (husbands only). Additionally, although partner sexual narcissism was unrelated to infidelity on average, partners' grandiose sense of sexual skill and partners' sexual entitlement (Study 2 only) were positively associated with infidelity, and partners' lack of sexual empathy was negatively associated with infidelity (Study 2 only). These findings highlight the benefits of using domain-specific measures of sexual narcissism in research on sexual behavior and the benefits of using domain-specific measures of personality more generally.

Mechanisms of lipase maturation

PubMed Central

Péterfy, Miklós

2010-01-01

Lipases are acyl hydrolases that represent a diverse group of enzymes present in organisms ranging from prokaryotes to humans. This article focuses on an evolutionarily related family of extracellular lipases that include lipoprotein lipase, hepatic lipase and endothelial lipase. As newly synthesized proteins, these lipases undergo a series of co- and post-translational maturation steps occurring in the endoplasmic reticulum, including glycosylation and glycan processing, and protein folding and subunit assembly. This article identifies and discusses mechanisms that direct early and late events in lipase folding and assembly. Lipase maturation employs the two general chaperone systems operating in the endoplasmic reticulum, as well as a recently identified lipase-specific chaperone termed lipase maturation factor 1. We propose that the two general chaperone systems act in a coordinated manner early in lipase maturation in order to help create partially folded monomers; lipase maturation factor 1 then facilitates final monomer folding and subunit assembly into fully functional homodimers. Once maturation is complete, the lipases exit the endoplasmic reticulum and are secreted to extracellular sites, where they carry out a number of functions related to lipoprotein and lipid metabolism. PMID:20543905

In- and outdoor reproduction of first generation common sole Solea solea under a natural photothermal regime: Temporal progression of sexual maturation assessed by monitoring plasma steroids and gonadotropin mRNA expression.

PubMed

Palstra, A P; Blok, M C; Kals, J; Blom, E; Tuinhof-Koelma, N; Dirks, R P; Forlenza, M; Blonk, R J W

2015-09-15

Reproduction of many temperate fishes is seasonal and maturation and spawning of gametes are under photothermal control. Reproductive success of first generation (G1) common sole Solea solea in captivity has been low. In this study, the sexual maturation status has been assessed during the prespawning months in G1 sole that were housed (a) outdoor under the natural photoperiod and temperature, or (b) indoor under artificial photothermal induction. Maturation was assessed in male and female G1 broodstock in November as controls, after which the remaining population was divided over two outdoor flow-through tanks placed in a pond and two indoor recirculating aquaculture system (RAS) tanks. Subsequently, maturation status (gonadosomatic index GSI and plasma levels of testosterone T and 17β-estradiol E2) was assessed in one tank for each condition in January, February and during spawning in early April, while fish in the other tank were not disturbed in achieving reproductive success. Quantitative real-time PCR was performed to determine species-specific gonadotropin mRNA expression in females. Successful G1 spawning and egg fertilisation occurred in all experimental tanks. Gonadal development was similar under both conditions. Higher E2 and T levels were found in indoor housed females. Gonadotropin expression revealed similar profiles between outdoor and indoor housed females. G1 sole could be reproduced in the outdoor tanks under the natural photoperiod and in the indoor tanks under artificial simulation of this regime that includes a potentially crucial chilling period of 2-3 months at 5-7 °C. Copyright © 2015 Elsevier Inc. All rights reserved.

Sexual Communication Between Early Adolescents and Their Dating Partners, Parents, and Best Friends

PubMed Central

Widman, Laura; Choukas-Bradley, Sophia; Helms, Sarah W.; Golin, Carol E.; Prinstein, Mitchell J.

2014-01-01

This study assessed early adolescents' sexual communication with dating partners, parents, and best friends about six sexual health topics: condoms, birth control, STDs, HIV/AIDS, pregnancy, and abstinence/waiting. Using a school-based sample of 603 youth (ages = 12–15; 57% female; 46% Caucasian), we examined communication differences across demographic and developmental factors, tested whether communication with parents and best friends was associated with greater communication with partners, and examined associations between communication and condom use. Over half of participants had not discussed any sexual topics with their dating partners (54%), and many had not communicated with parents (29%) or best friends (25%). On average, communication was more frequent among adolescents who were female, African American, older, and sexually active, despite some variation in subgroups across partner, parent, and friend communication. Importantly, communication with parents and friends – and the interaction between parent and friend communication – was associated with increased communication with dating partners. Further, among sexually active youth, increased sexual communication with partners was associated with more frequent condom use. Results highlight the importance of understanding the broader family and peer context surrounding adolescent sexual decision-making and suggest a possible need to tailor sexual communication interventions. PMID:24354655

Is the technical performance of young soccer players influenced by hormonal status, sexual maturity, anthropometric profile, and physical performance?

PubMed

Moreira, Alexandre; Massa, Marcelo; Thiengo, Carlos R; Rodrigues Lopes, Rafael Alan; Lima, Marcelo R; Vaeyens, Roel; Barbosa, Wesley P; Aoki, Marcelo S

2017-12-01

The aim of this study was to examine the influence of hormonal status, anthropometric profile, sexual maturity level, and physical performance on the technical abilities of 40 young male soccer players during small-sided games (SSGs). Anthropometric profiling, saliva sampling, sexual maturity assessment (Tanner scale), and physical performance tests (Yo-Yo and vertical jumps) were conducted two weeks prior to the SSGs. Salivary testosterone was determined by the enzyme-linked immunosorbent assay method. Technical performance was determined by the frequency of actions during SSGs. Principal component analyses identified four technical actions of importance: total number of passes, effectiveness, goal attempts, and total tackles. A multivariate canonical correlation analysis was then employed to verify the prediction of a multiple dependent variables set (composed of four technical actions) from an independent set of variables, composed of testosterone concentration, stage of pubic hair and genitalia development, vertical jumps and Yo-Yo performance. A moderate-to-large relationship between the technical performance set and the independent set was observed. The canonical correlation was 0.75 with a canonical R 2 of 0.45. The highest structure coefficient in the technical performance set was observed for tackles (0.77), while testosterone presented the highest structure coefficient (0.75) for the variables of the independent set. The current data suggest that the selected independent set of variables might be useful in predicting SSG performance in young soccer players. Coaches should be aware that physical development plays a key role in technical performance to avoid decision-making mistakes during the selection of young players.

Reduced embryonic survival in rainbow trout resulting from paternal exposure to the environmental estrogen 17 alpha- ethynylestradiol during late sexual maturation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, Kim H.; Schultz, Irvin R.; Nagler, James J.

Exposure of fishes to environmental estrogens is known to affect sexual development and spawning, but little information exists regarding effects on gametes. This study evaluated embryonic survival of offspring from male rainbow trout (Oncorhynchus mykiss) exposed to 17a-ethynylestradiol (EE 2)using an in vitro fertilization protocol. Males were exposed at either 1800 or 6700 degree days (8d) (i.e. 161 or 587 days post-fertilization (dpf)) to test for effects on testes linked to reproductive ontogeny. At 18008d, fish were beginning testicular differentiation and were exposed to 109 ng EE 2/l for 21 days. At 67008d, fish have testes containing spermatocytes and spermatidsmore » and were exposed for 56 days to either 0.8, 8.3, or 65 ng EE 2/l. Semen was collected at full sexual maturity in each group and used to fertilize eggs pooled from several non-exposed females. Significant decreases in embryonic survival were observed only with the 67008d exposure. In 0.8 and 8.3 ng EE 2/l treatments, embryo survival was significantly reduced at 19 dpf when compared with the control. In contrast, an immediate decrease in embryonic survival at 0.5 dpf was observed in the 65 ng EE 2/l treatment. Blood samples collected at spawning from 67008d exposed males revealed a significant decrease in 11-ketotestosterone and a significant increase in luteinizing hormone levels for the 65 ng EE 2/l treatment when compared with the other treatment groups. Results indicate that sexually maturing male rainbow trout are susceptible to EE 2 exposure with these fish exhibiting two possible mechanisms of reduced embryonic survival through sperm varying dependant« less

Reduced embryonic survival in rainbow trout resulting from paternal exposure to the environmental estrogen 17α-ethynylestradiol during late sexual maturation

PubMed Central

Brown, Kim H; Schultz, Irvin R; Nagler, James J

2007-01-01

Exposure of fishes to environmental estrogens is known to affect sexual development and spawning, but little information exists regarding effects on gametes. This study evaluated embryonic survival of offspring from male rainbow trout (Oncorhynchus mykiss) exposed to 17α-ethynylestradiol (EE2) using an in vitro fertilization protocol. Males were exposed at either 1800 or 6700 degree days (°d) (i.e. 161 or 587 days post-fertilization (dpf)) to test for effects on testes linked to reproductive ontogeny. At 1800°d, fish were beginning testicular differentiation and were exposed to 109 ng EE2/l for 21 days. At 6700°d, fish have testes containing spermatocytes and spermatids and were exposed for 56 days to either 0.8, 8.3, or 65 ng EE2/l. Semen was collected at full sexual maturity in each group and used to fertilize eggs pooled from several non-exposed females. Significant decreases in embryonic survival were observed only with the 6700°d exposure. In 0.8 and 8.3 ng EE2/l treatments, embryo survival was significantly reduced at 19 dpf when compared with the control. In contrast, an immediate decrease in embryonic survival at 0.5 dpf was observed in the 65 ng EE2/l treatment. Blood samples collected at spawning from 6700°d exposed males revealed a significant decrease in 11-ketotestosterone and a significant increase in luteinizing hormone levels for the 65 ng EE2/l treatment when compared with the other treatment groups. Results indicate that sexually maturing male rainbow trout are susceptible to EE2 exposure with these fish exhibiting two possible mechanisms of reduced embryonic survival through sperm varying dependant on EE2 exposure concentrations experienced. PMID:17965256

The Control of Sexuality in the Early British Boy Scouts Movement

ERIC Educational Resources Information Center

Pryke, Sam

2005-01-01

This article looks at the way in which the early (1907-1922) British Boy Scouts movement attempted to control sexuality through archival examination of the organization's preoccupation with preventing masturbation or, as it was generally referred to, "self abuse". Having briefly outlined the origination and nature of the Scouts, it considers why…

Comparisons of body sizes at sexual maturity and at sex change in the parrotfishes of Hawaii: input needed for management regulations and stock assessments.

PubMed

DeMartini, E E; Howard, K G

2016-02-01

First estimates of sex allocation patterns and body size-at-sexual maturity and at protogynous sex change are presented for the five major (including one endemic) species of parrotfishes of Hawaii. Median body size at initial maturation as a female (LM50) and at protogynous sex change from adult female to adult male (LΔ50) varied greatly among the five species. Estimates of LM50 were about 14, 17, 24, 34 and 35 cm fork length (LF) in palenose Scarus psittacus, Pacific bullethead Chlorurus spilurus, stareye Calotomus carolinus, spectacled Chlorurus perspicillatus and redlip parrotfish Scarus rubroviolaceus. Values of LΔ50 were c. 23, 27, 37, 46 and 47 cm LF in the respective species. Length at female maturation was proportional to maximum body size (Lmax) of the respective species, ranging from 50 to 72% and averaging 62% of Lmax across species. LΔ50 was also proportional to Lmax, ranging from 82 to 97% and averaging 92%. Males of both pairs of Scarus and Chlorurus spp. reported here are diandric. Only one of the five major species (C. carolinus) is functionally monandric, with either all or nearly all males secondarily derived from adult females. The broadly differing absolute body sizes at sexual maturation and at sex change among the five species have important implications for improving regulatory size limits for parrotfishes in the State of Hawaii, where parrotfish species have historically been managed based on a single minimum size limit of 30·5 cm LF. This study provides a model demonstration of why catch data for parrotfishes, and other size-structured reef-fish populations, should be recorded either by species or by functional size-groups of species that allow setting more meaningful minimum size limits. © 2016 The Fisheries Society of the British Isles.

Individual condition and stream temperature influence early maturation of rainbow and steelhead trout, ncorhynchus mykiss

USGS Publications Warehouse

McMillan, John R.; Dunham, Jason B.; Reeves, Gordon H.; Mills, Justin S.; Jordan, Chris E.

2012-01-01

Alternative male phenotypes in salmonine fishes arise from individuals that mature as larger and older anadromous marine-migrants or as smaller and younger freshwater residents. To better understand the processes influencing the expression of these phenotypes we examined the influences of growth in length (fork length) and whole body lipid content in rainbow trout (Oncorhynchus mykiss). Fish were sampled from the John Day River basin in northeast Oregon where both anadromous ("steelhead") and freshwater resident rainbow trout coexist. Larger males with higher lipid levels had a greater probability of maturing as a resident at age-1+. Among males, 38% were maturing overall, and the odds ratios of the logistic model indicated that the probability of a male maturing early as a resident at age-1+ increased 49% (95% confidence interval (CI) = 23-81%) for every 5 mm increase in length and 33% (95% CI = 10-61%) for every 0.5% increase in whole body lipid content. There was an inverse association between individual condition and water temperature as growth was greater in warmer streams while whole body lipid content was higher in cooler streams. Our results support predictions from life history theory and further suggest that relationships between individual condition, maturation, and environmental variables (e.g., water temperature) are shaped by complex developmental and evolutionary influences.

Teenage sexual behaviour: attitudes towards and declared sexual activity.

PubMed

Burack, R

1999-01-01

Although the teenage pregnancy rates in the UK are falling in the 16 to 19 year old range, they are still rising in the 13 to 15 year olds. Overall, they remain one of the highest within Western Europe. Teenagers continue to present a challenge to the health services due to the increase in their sexual risk taking behaviour, the earlier age at which they are starting sexual activity and a reluctance to utilise services available to them. In an attempt to develop current services and make them more 'user friendly', a sexual health needs assessment was carried out on teenagers, part of which looked at their attitudes towards risk taking sexual behaviour and their declared sexual behaviour. A quantitative survey, using a questionnaire in schools, was answered by 1500 pupils aged between 13 and 18 years old, and showed that the majority of teenagers had declared some form of sexual contact with a partner with a degree of sexual activity increasing with age. Twenty per cent of 13 year olds reported that they had already had either full or oral sexual intercourse with a partner. Feeling peer pressure, not knowing the facts about sexual risk taking and a declared intent that would increase the likelihood of putting themselves or others at risk sexually were significantly more likely in the younger teenage boys surveyed. This study confirms that there remain many different factors involved in teenagers' decision-making processes, about their developing attitudes towards sex and their resultant behaviour. Despite a lack of maturity, such opinions and attitudes are bringing about definite views and sexual behaviour patterns in teenagers as young as 12 or 13 years old who are becoming fully sexually active. In particular teenage boys are becoming fully sexually active at a younger age than the girls and are taking risks in doing so. They are being influenced by peer pressure, condoning promiscuity and are declaring the intent to practice unsafe sexual intercourse. Their level

Dopamine receptor gene d4 polymorphisms and early sexual onset: gender and environmental moderation in a sample of african-american youth.

PubMed

Kogan, Steven M; Lei, Man-Kit; Beach, Steven R H; Brody, Gene H; Windle, Michael; Lee, Sunbok; MacKillop, James; Chen, Yi-Fu

2014-08-01

Early sexual onset and its consequences disproportionately affect African-American youth, particularly male youth. The dopamine receptor D4 gene (DRD4) has been linked to sexual activity and other forms of appetitive behavior, particularly for male youth and in combination with environmental factors (gene × environment [G × E] effects). The differential susceptibility perspective suggests that DRD4 may exert this effect by amplifying the effects of both positive and negative environments. We hypothesized that DRD4 status would amplify the influence of both positive and negative neighborhood environments on early sexual onset among male, but not female, African-Americans. Hypotheses were tested with self-report, biospecimen, and census data from five prospective studies of male and female African-American youth in rural Georgia communities, N = 1,677. Early sexual onset was defined as intercourse before age 14. No significant G × E findings emerged for female youth. Male youth with a DRD4 long allele were more likely than those with two DRD4 short alleles to report early sexual onset in negative community environments and not to report early onset in positive community environments. Dopaminergic regulation of adolescent sexual behaviors may operate differently by gender. DRD4 operated as an environmental amplification rather than a vulnerability factor. Copyright © 2014 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Changing patterns of adolescent sexual behavior: consequences for health and development.

PubMed

Friedman, H L

1992-07-01

Sexuality is a fundamental quality of human life, important for health, happiness, individual development, and indeed for the preservation of the human race. During the dynamic period of adolescence in which the passage from childhood to maturity takes place, sexuality takes on new dimensions; feelings become more intense, relationships become more complex, and the consequences of sexual behavior are radically altered. This not only affects the behavior of young people but also of those who interact with them, their families and peers, and those who work in the health, education, youth, social welfare, and other sectors. In the contemporary world the conditions of life for many young people have also changed, and with it patterns of sexual behavior. In general, earlier puberty, later marriage, a decline in the family leading to less control and more autonomy, and intense exposure to sexual stimuli via the mass media and travel across cultural boundaries have made pre-marital adolescent sexual activity more common. This has added to traditional problems of early marriage, newer problems of early pregnancy, childbirth, and induced abortion outside of marriage, sexually transmitted diseases, and human immunodeficiency syndrome infection leading to acquired immunodeficiency syndrome. But the work of the World Health Organization (WHO), along with many others in the field, strongly suggests that given appropriate information and services, trust and equity between the sexes, young people will behave responsibly and well. In this paper some of the findings from methods developed by WHO for research, training, advocacy, and evaluation, and findings in relation to patterns and determinants of sexual and reproductive health and development will be described, and future directions suggested.

A thermogenic secondary sexual character in male sea lamprey

USGS Publications Warehouse

Chung-Davidson, Yu-Wen; Priess, M. Cody; Yeh, Chu-Yin; Brant, Cory O.; Johnson, Nicholas S.; Li, Ke; Nanlohy, Kaben G.; Bryan, Mara B.; Brown, C. Titus; Choi, Jongeun; Li, Weiming

2013-01-01

Secondary sexual characters in animals are exaggerated ornaments or weapons for intrasexual competition. Unexpectedly, we found that a male secondary sexual character in sea lamprey (Petromyzon marinus ) is a thermogenic adipose tissue that instantly increases its heat production during sexual encounters. This secondary sexual character, developed in front of the anterior dorsal fin of mature males, is a swollen dorsal ridge known as the ‘rope’ tissue. It contains nerve bundles, multivacuolar adipocytes and interstitial cells packed with small lipid droplets and mitochondria with dense and highly organized cristae. The fatty acid composition of the rope tissue is rich in unsaturated fatty acids. The cytochrome c oxidase activity is high but the ATP concentration is very low in the mitochondria of the rope tissue compared with those of the gill and muscle tissues. The rope tissue temperature immediately rose up to 0.3°C when the male encountered a conspecific. Mature males generated more heat in the rope and muscle tissues when presented with a mature female than when presented with a male (paired t-test, P-3 more heat than the muscle in 10 min. Transcriptome analyses revealed that genes involved in fat cell differentiation are upregulated whereas those involved in oxidative-phosphorylation-coupled ATP synthesis are downregulated in the rope tissue compared with the gill and muscle tissues. Sexually mature male sea lamprey possess the only known thermogenic secondary sexual character that shows differential heat generation toward individual conspecifics.

Early life vitamin D depletion alters the postnatal response to skeletal loading in growing and mature bone

PubMed Central

Buckley, Harriet; Owen, Robert; Marin, Ana Campos; Lu, Yongtau; Eyles, Darryl; Lacroix, Damien; Reilly, Gwendolen C.; Skerry, Tim M.; Bishop, Nick J.

2018-01-01

There is increasing evidence of persistent effects of early life vitamin D exposure on later skeletal health; linking low levels in early life to smaller bone size in childhood as well as increased fracture risk later in adulthood, independently of later vitamin D status. A major determinant of bone mass acquisition across all ages is mechanical loading. We tested the hypothesis in an animal model system that early life vitamin D depletion results in abrogation of the response to mechanical loading, with consequent reduction in bone size, mass and strength during both childhood and adulthood. A murine model was created in which pregnant dams were either vitamin D deficient or replete, and their offspring moved to a vitamin D replete diet at weaning. Tibias of the offspring were mechanically loaded and bone structure, extrinsic strength and growth measured both during growth and after skeletal maturity. Offspring of vitamin D deplete mice demonstrated lower bone mass in the non loaded limb and reduced bone mass accrual in response to loading in both the growing skeleton and after skeletal maturity. Early life vitamin D depletion led to reduced bone strength and altered bone biomechanical properties. These findings suggest early life vitamin D status may, in part, determine the propensity to osteoporosis and fracture that blights later life in many individuals. PMID:29370213

Delaying sexual debut amongst out-of-school youth in rural southwest Uganda.

PubMed

Nobelius, Ann-Maree; Kalina, Bessie; Pool, Robert; Whitworth, Jimmy; Chesters, Janice; Power, Robert

2010-08-01

This paper focuses on 'sexual debut' among out-of-school youth in Masaka District, Uganda, factors influencing its timing and assistance young people feel they need to delay sexual initiation. Data were drawn from a sexual health needs assessment using applied anthropological techniques with young people aged 13-19 years. Parents, guardians and community leaders were also consulted. All participants felt that young people begin their sexual lives too early. Young men feel under pressure from friends and older men to prove their masculinity. Most delay further activity after debut and want assistance to resist the pressure. Young women's debut after physical maturation prompts 'pestering' for sex from boys and men who offer gifts. After debut, young women remain sexually active but believe younger women need assistance to resist pressure. Programmes are needed to help young people achieve these goals. Structurally, the community needs to develop means of preventing men from pestering young women for sex and of redeveloping both the social role and pathway to marriage for young women who are marrying later than is traditional.

Factors Influencing Attitudes toward Sexual Activity among Early Adolescents in Japan

ERIC Educational Resources Information Center

Nagamatsu, Miyuki; Yamawaki, Niwako; Sato, Takeshi; Nakagawa, Aki; Saito, Hisako

2013-01-01

The purpose of this study was to examine factors influencing attitudes toward sexual activity among early adolescents in Japan. A total of 1,551 students aged 12 to 14 years at 4 junior high schools were divided into either a conservative or liberal group. Results of chi-square tests showed that the liberal group had higher percentages of students…

The Association Between Maternal Early Life Forced Sexual Intercourse and Offspring Birth Weight: The Role of Socioeconomic Status.

PubMed

Gavin, Amelia R; Morris, Julia

2017-05-01

This study utilizes a life-course framework to investigate whether maternal early life forced sexual intercourse operates in conjunction with health behaviors during adolescence, young adulthood, and the prenatal period to influence offspring birth weight. Using data from the 1994-2009 National Longitudinal Study of Adolescent Health (Add Health), we examined whether early life forced sexual intercourse predicted offspring birth weight through a mediated pathway, including depressive symptoms, substance use, and prenatal cigarette smoking. We stratify our analysis by socioeconomic status (SES) to determine whether the proposed pathways operate similarly, or differently, according to SES. Our findings suggest that the pathways through which forced sexual intercourse affects offspring birth weight differ by SES. Among middle-to-high SES women, we found a mediated pathway linking forced sexual intercourse to offspring birth weight with prenatal cigarette smoking predicting lower offspring birth weight. Among low SES women, however, we did not find a mediated pathway linking forced sexual intercourse to birth weight. Findings suggest that prenatal cigarette smoking was not a mechanism of influence in the pathway between maternal early life forced sexual intercourse and offspring birth weight for low SES women. Our findings suggest that forced sexual intercourse may influence infant birth weight in the next generation. Infants born with a low birth weight are at increased risk for a myriad of adverse outcomes across the life-course. Study results suggest the importance of interventions designed to reduce behavioral risks and to support health promoting behaviors among survivors in the short term, in an effort to prevent long-term consequences among later-born offspring.

Illustrating phallic worship: uses of material objects and the production of sexual knowledge in eighteenth-century antiquarianism and early twentieth-century sexual science.

PubMed

Funke, Jana; Fisher, Kate; Grove, Jen; Langlands, Rebecca

2017-07-03

This article reveals previously overlooked connections between eighteenth-century antiquarianism and early twentieth-century sexual science by presenting a comparative reading of two illustrated books: An Account of the Remains of the Worship of Priapus , by British antiquarian scholar Richard Payne Knight (1750-1824), and Die Weltreise eines Sexualforschers (The World Journey of a Sexologist), by German sexual scientist Magnus Hirschfeld (1868-1935). A close analysis of these publications demonstrates the special status of material artefacts and the strategic engagement with visual evidence in antiquarian and scientific writings about sex. Through its exploration of the similarities between antiquarian and sexual scientific thought, the article demonstrates the centrality of material culture to the production of sexual knowledge in the Western world. It also opens up new perspectives on Western intellectual history and on the intellectual origins of sexual science. While previous scholarship has traced the beginnings of sexual science back to nineteenth-century medical disciplines, this article shows that sexual scientists drew upon different forms of evidence and varied methodologies to produce sexual knowledge and secure scientific authority. As such, sexual science needs to be understood as a field with diverse intellectual roots that can be traced back (at least) to the eighteenth century.

Illustrating phallic worship: uses of material objects and the production of sexual knowledge in eighteenth-century antiquarianism and early twentieth-century sexual science

PubMed Central

Funke, Jana; Fisher, Kate; Grove, Jen; Langlands, Rebecca

2017-01-01

Abstract This article reveals previously overlooked connections between eighteenth-century antiquarianism and early twentieth-century sexual science by presenting a comparative reading of two illustrated books: An Account of the Remains of the Worship of Priapus, by British antiquarian scholar Richard Payne Knight (1750–1824), and Die Weltreise eines Sexualforschers (The World Journey of a Sexologist), by German sexual scientist Magnus Hirschfeld (1868–1935). A close analysis of these publications demonstrates the special status of material artefacts and the strategic engagement with visual evidence in antiquarian and scientific writings about sex. Through its exploration of the similarities between antiquarian and sexual scientific thought, the article demonstrates the centrality of material culture to the production of sexual knowledge in the Western world. It also opens up new perspectives on Western intellectual history and on the intellectual origins of sexual science. While previous scholarship has traced the beginnings of sexual science back to nineteenth-century medical disciplines, this article shows that sexual scientists drew upon different forms of evidence and varied methodologies to produce sexual knowledge and secure scientific authority. As such, sexual science needs to be understood as a field with diverse intellectual roots that can be traced back (at least) to the eighteenth century. PMID:29393929

The impact of early repeated pain experiences on stress responsiveness and emotionality at maturity in rats.

PubMed

Page, Gayle G; Blakely, Wendy P; Kim, Miyong

2005-01-01

The intensive care necessary for premature newborns is characterized by multiple procedures, many of which are painful. Given emerging evidence that such early pain during this time of high brain plasticity may affect long-term neurodevelopmental and social-emotional functioning, this study explored the impact of early repeated pain on emotionality and stress responsivity at maturity. From birth through postnatal day 7, Fischer 344 pups underwent either paw needle prick every day versus every other day or daily paw touch, or were left unperturbed. Each paw received the designated perturbation once per day. At maturity, some animals underwent emotionality testing: either a 4-day series of open field exposures or a single elevated plus-maze (EPM) exposure. The paw prick groups exhibited less open field habituation and occupied the EPM open arms more. Two weeks later, all animals were either subjected to forced swim or not. At 1h post-swim, animals underwent either blood withdrawal for plasma corticosterone (CS) levels and ex vivo natural killer cell activity (NKCA) or were injected intravenously with radiolabeled NK-sensitive syngeneic MADB106 tumor cells and assessed for lung tumor retention. Sex was a major factor in the manifestation of perturbation-related differences in the biologic outcomes. Whereas postnatal pain differentially affected baseline tumor retention between males and females, only males exhibited perturbation-related differences in swim stress-induced increases in tumor retention and CS. Finally, male-female differences were evident in CS, NKCA, and tumor responses to swim stress. These findings suggest that early pain affects neurodevelopmental function in the mature organism; however, these relationships are complicated by sex differences, the postnatal pain schedule, and the outcome measured.

Acne vulgaris in early adolescent boys. Correlations with pubertal maturation and age.

PubMed

Lucky, A W; Biro, F M; Huster, G A; Morrison, J A; Elder, N

1991-02-01

To assess the prevalence and severity of acne vulgaris in young adolescent boys, we studied 219 black and 249 white boys in fifth through ninth grades in Cincinnati, Ohio. The mean age was 12.2 +/- 1.4 years, with a range of 9 to 15 years. Pubertal maturation was scored as Tanner pubic hair stages (PH I to V) and pubertal stages (PS I to IV) that included testicular volume assessment. Acne was scored by number of comedonal (open plus closed comedones) and inflammatory (papules plus pustules) lesions. Comedonal and inflammatory lesions were analyzed separately and evaluated both as numerical scores and as grades (1, less than or equal to 10 lesions; 2, 11 to 25 lesions; and 3, greater than or equal to 26 lesions). Grades 2 and 3 were considered clinically significant acne. Acne became progressively more severe with advancing maturity. Mean acne scores correlated better with PS and pubic hair than with age. Black subjects were more mature than white subjects. Black boys in PSI and II had significantly more comedones than white boys; white boys had significantly more inflammatory lesions at PS I and III. Clinically significant comedonal acne was already present in PS I and occurred in 100% of boys in PS IV. In contrast, no boys at PS I and only 50% at PS IV had significant inflammatory acne. Midfacial acne dominated. We concluded that acne prevalence and severity correlate well with advancing pubertal maturation in young adolescent boys. Comedonal acne was more frequent and severe than inflammatory disease. Awareness of the extent and severity of acne in preadolescents and young adolescents may ultimately provide rationale for early intervention and thus prevention of severe acne vulgaris.

Short-term exposure to 17alpha-ethynylestradiol decreases the fertility of sexually maturing male rainbow trout (Oncorhynchus mykiss)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schultz, Irv R.; Skillman, Ann D.; Nicolas, Jean-Marc

The synthetic estrogen 17alpha-ethynylestradiol (EE2) is a commonly used oral contraceptive that has been increasingly detected in sewage effluents. This study determined whether EE2 exposure adversely affected reproduction in sexually maturing male rainbow trout (Oncorhynchus mykiss). We exposed male trout to graded water concentrations of EE2 (10, 100, and 1,000 ng/ L) for 62 d leading up to the time of spawning. Semen and blood plasma samples were removed from each fish. Semen was used to fertilize groups of eggs from one nonexposed female. As a measure of fertility, eggs were incubated for 28 d after fertilization to determine themore » proportion that attained the eyed stage of embryonic development. Additional endpoints also measured included sperm motility, spermatocrit, gonadosomatic and hepatosomatic indices, testis histology, and circulating plasma levels of the sex steroids 17alpha, 20beta-dihydroxyprogesterone (17,20-DHP) and 11-ketotestosterone (11-KT). Exposure to 1,000 ng/L of EE2 caused complete mortality of the treatment group by day 57. Exposure to lower EE2 water concentrations (10 and 100 ng/L) caused an increase in sperm density, while a significant reduction in testis mass was observed only in the 100-ng/L exposure group. Most significantly, semen harvested from fish exposed to 10 and 100 ng/L EE2 caused an approximately 50% reduction in the number of eggs attaining the eyed stage of embryonic development. Plasma levels of 17,20-DHP in exposed fish were roughly twice the level of the controls, while levels of 11-KT were significantly reduced in fish exposed to 100 ng/L EE2. These results suggest that sexually maturing male rainbow trout are susceptible to detrimental reproductive effects of short-term exposures to environmentally relevant levels of EE2.« less

Short-term exposure to 17 alpha-ethynylestradiol decreases the fertility of sexually maturing male rainbow trout (Oncorhynchus mykiss).

PubMed

Schultz, Irvin R; Skillman, Ann; Nicolas, Jean-Marc; Cyr, Daniel G; Nagler, James J

2003-06-01

The synthetic estrogen 17 alpha-ethynylestradiol (EE2) is a commonly used oral contraceptive that has been increasingly detected in sewage effluents. This study determined whether EE2 exposure adversely affected reproduction in sexually maturing male rainbow trout (Oncorhynchus mykiss). We exposed male trout to graded water concentrations of EE2 (10, 100, and 1,000 ng/ L) for 62 d leading up to the time of spawning. Semen and blood plasma samples were removed from each fish. Semen was used to fertilize groups of eggs from one nonexposed female. As a measure of fertility, eggs were incubated for 28 d after fertilization to determine the proportion that attained the eyed stage of embryonic development. Additional endpoints also measured included sperm motility, spermatocrit, gonadosomatic and hepatosomatic indices, testis histology, and circulating plasma levels of the sex steroids 17 alpha, 20 beta-dihydroxyprogesterone (17,20-DHP) and 11-ketotestosterone (11-KT). Exposure to 1,000 ng/L of EE2 caused complete mortality of the treatment group by day 57. Exposure to lower EE2 water concentrations (10 and 100 ng/L) caused an increase in sperm density, while a significant reduction in testis mass was observed only in the 100-ng/L exposure group. Most significantly, semen harvested from fish exposed to 10 and 100 ng/L EE2 caused an approximately 50% reduction in the number of eggs attaining the eyed stage of embryonic development. Plasma levels of 17,20-DHP in exposed fish were roughly twice the level of the controls, while levels of 11-KT were significantly reduced in fish exposed to 100 ng/L EE2. These results suggest that sexually maturing male rainbow trout are susceptible to detrimental reproductive effects of short-term exposures to environmentally relevant levels of EE2.

Genome-wide association mapping of flowering time and maturity dates in early mature soybean germplasm

USDA-ARS?s Scientific Manuscript database

Soybean (Glycine max L. Merr.) is a photoperiod-sensitive and short-day major crop grown worldwide. Days to flowering (DTF) and maturity (DTM) are two traits affecting soybean adaptability and yield. Some genes conditioning soybean flowering and maturity have been recently characterized. However, ...

Early Adolescent Sexual Initiation and Physical/Psychological Symptoms: A Comparative Analysis of Five Nations

PubMed Central

Farhat, Tilda; Halpern, Carolyn Tucker; Godeau, Emmanuelle; Gabhainn, Saoirse Nic

2010-01-01

Although most people in developed countries experience sexual initiation during adolescence, little is known about inter-country variability in the psychosocial correlates of early initiation. Population-based samples of 15-year-olds (n = 6,111, 52% female) who participated in the Health Behaviors in School-Aged Children Study (Finland, Scotland, France and Poland, 1997/1998) or the National Longitudinal Study of Adolescent Health (United States, 1996) self-reported sexual intercourse experience and physical (headaches, trouble sleeping) or psychological (unhappiness, loneliness, sadness, moodiness) symptoms. Analyses were conducted stratified by gender. Sexual initiation prevalence and symptoms scores varied significantly across nations. In adjusted models, sexual initiation was not related to symptoms among boys in any nation, but significantly positively related to symptoms among girls in Poland and the US. Results support variability by gender and nation in the relationship between adolescents’ sexual initiation and physical/psychological symptoms. Empirically investigating specific features of national contexts that generate these differences should be explored further. PMID:20333456

Early adolescent sexual initiation and physical/psychological symptoms: a comparative analysis of five nations.

PubMed

Madkour, Aubrey Spriggs; Farhat, Tilda; Halpern, Carolyn Tucker; Godeau, Emmanuelle; Nic Gabhainn, Saoirse

2010-10-01

Although most people in developed countries experience sexual initiation during adolescence, little is known about inter-country variability in the psychosocial correlates of early initiation. Population-based samples of 15-year-olds (n = 6,111, 52% female) who participated in the Health Behaviors in School-Aged Children Study (Finland, Scotland, France and Poland, 1997/1998) or the National Longitudinal Study of Adolescent Health (United States, 1996) self-reported sexual intercourse experience and physical (headaches, trouble sleeping) or psychological (unhappiness, loneliness, sadness, moodiness) symptoms. Analyses were conducted stratified by gender. Sexual initiation prevalence and symptoms scores varied significantly across nations. In adjusted models, sexual initiation was not related to symptoms among boys in any nation, but significantly positively related to symptoms among girls in Poland and the US. Results support variability by gender and nation in the relationship between adolescents' sexual initiation and physical/psychological symptoms. Empirically investigating specific features of national contexts that generate these differences should be explored further.

The RY/Sph element mediates transcriptional repression of maturation genes from late maturation to early seedling growth.

PubMed

Guerriero, Gea; Martin, Nathalie; Golovko, Anna; Sundström, Jens F; Rask, Lars; Ezcurra, Ines

2009-11-01

In orthodox seeds, the transcriptional activator ABI3 regulates two major stages in embryo maturation: a mid-maturation (MAT) stage leading to accumulation of storage compounds, and a late maturation (LEA) stage leading to quiescence and desiccation tolerance. Our aim was to elucidate mechanisms for transcriptional shutdown of MAT genes during late maturation, to better understand phase transition between MAT and LEA stages. Using transgenic and transient approaches in Nicotiana, we examined activities of two ABI3-dependent reporter genes driven by multimeric RY and abscisic acid response elements (ABREs) from a Brassica napus napin gene, termed RY and ABRE, where the RY reporter requires ABI3 DNA binding. Expression of RY peaks during mid-maturation and drops during late maturation, mimicking the MAT gene program, and in Arabidopsis thaliana RY elements are over-represented in MAT, but not in LEA, genes. The ABI3 transactivation of RY is inhibited by staurosporine, by a PP2C phosphatase, and by a repressor of maturation genes, VAL1/HSI2. The RY element mediates repression of MAT genes, and we propose that transcriptional shutdown of the MAT program during late maturation involves inhibition of ABI3 DNA binding by dephosphorylation. Later, during seedling growth, VAL1/HSI2 family repressors silence MAT genes by binding RY elements.

The Number of Sexual Partners and Health-Risking Sexual Behavior: Prediction from High School Entry to High School Exit

PubMed Central

Van Ryzin, Mark J.; Johnson, Amber B.; Leve, Leslie D.; Hyoun, Kim K.

2013-01-01

Precursors to adolescent health-risking sexual behavior (HRSB) were examined in a normative sample of 373 adolescents (48.0% female, n = 178). Using a variable-oriented approach, we regressed the number of sexual partners at high school exit (age 17) on parental monitoring, association with delinquent peers, romantic relationship status, problem behavior, physical maturity, and tobacco and alcohol use at high school entry (age 14); all emerged as significant predictors except alcohol use and physical maturity (we found sex differences in physical maturity and romantic relationship status, with females being more advanced in both areas). Sexual experimentation at high school entry served to partially or fully mediate the impact of these factors. A person-oriented approach, using a broader measure of HRSB, found three subgroups of adolescents: abstainers, low-risk-takers, and high-risk-takers. Results predicting membership in these groups generally followed those from the variable-oriented analysis. Implications for the prevention of HRSB and future research directions are discussed. PMID:20703789

The number of sexual partners and health-risking sexual behavior: prediction from high school entry to high school exit.

PubMed

Van Ryzin, Mark J; Johnson, Amber B; Leve, Leslie D; Kim, Hyoun K

2011-10-01

Precursors to adolescent health-risking sexual behavior (HRSB) were examined in a normative sample of 373 adolescents (48.0% female, n = 178). Using a variable-oriented approach, we regressed the number of sexual partners at high school exit (age 17) on parental monitoring, association with delinquent peers, romantic relationship status, problem behavior, physical maturity, and tobacco and alcohol use at high school entry (age 14); all emerged as significant predictors except alcohol use and physical maturity (we found sex differences in physical maturity and romantic relationship status, with females being more advanced in both areas). Sexual experimentation at high school entry served to partially or fully mediate the impact of these factors. A person-oriented approach, using a broader measure of HRSB, found three subgroups of adolescents: abstainers, low-risk-takers, and high-risk-takers. Results predicting membership in these groups generally followed those from the variable-oriented analysis. Implications for the prevention of HRSB and future research directions are discussed.

Maternal Patterns of Marijuana Use and Early Sexual Behavior in Offspring of Teenage Mothers

PubMed Central

Goldschmidt, Lidush; Cornelius, Marie D.

2015-01-01

Teenage mothers use marijuana more frequently than older mothers, and marijuana use may predict HIV risk behavior in offspring. Our goals were to (1) describe trajectories of marijuana use in teenage mothers and (2) determine if these trajectories were associated with early sexual behavior in their offspring. Pregnant adolescents (12–18 years) were recruited at a prenatal clinic and interviewed during pregnancy, at delivery, and during follow-up visits when offspring were 6, 10, 14 and 16 years old. At 16 years, 332 women (71 % Black, 29 % White) and their offspring were assessed. Mothers were asked about their marijuana use at each time point. Offspring reported on their sexual behavior at age 14. Trajectory analyses using growth mixture models revealed four maternal patterns of marijuana use: no use, only at the 6 year follow-up, quit by the 16 year follow-up, and used across most of the time points. The children of chronic users were more likely to have early sex. The maternal marijuana trajectory group variable remained a statistically significant predictor in multivariate models controlling for race, gender, socioeconomic status, child pubertal timing, child externalizing behavior problems, and child marijuana use. These findings suggest that a minority of teenage mothers continue to use marijuana over time. Chronic maternal marijuana use across a decade was associated with early sex in offspring (oral or vaginal sex by age 14). Early sexual behavior places these children at significantly higher risk of teenage pregnancy and HIV risk behaviors. PMID:24942139

Examining negative effects of early life experiences on reproductive and sexual health among female sex workers in Tijuana, Mexico

PubMed Central

Oza, Karishma K.; Silverman, Jay G.; Bojorquez, Ietza; Strathdee, Steffanie A.; Goldenberg, Shira M.

2014-01-01

Objective To explore experiences during childhood and adolescence that influenced reproductive and sexual health among women who had entered the sex industry in adolescence. Methods A qualitative study was conducted using information provided by 25 female sex workers (FSWs) from Tijuana, Mexico, who reported entering the sex industry when younger than 18 years. In-depth, semi-structured interviews were conducted with all participants between January 31, 2011, and July 8, 2011. Results Four interrelated themes that shaped health experiences—early sexual abuse, early illicit drug use, ongoing violence, and limited access to reproductive and sexual health care—were identified. Participants reporting these experiences were at risk of unintended teenaged pregnancy, spontaneous abortion or stillbirth, and untreated sexually transmitted infections. Conclusion Programs and policies that address social, structural, and individual vulnerabilities during adolescence and adulthood are required to promote reproductive and sexual health among FSWs in Tijuana, Mexico. PMID:25458416

Measures of maturation in early fossil hominins: events at the first transition from australopiths to early Homo

PubMed Central

Dean, M. Christopher

2016-01-01

An important question in palaeoanthropology is whether, among the australopiths and the first fossil hominins attributed to early Homo, there was a shift towards a more prolonged period of growth that can be distinguished from that of the living great apes and whether between the end of weaning and the beginning of puberty there was a slow period of growth as there is in modern humans. Evidence for the pace of growth in early fossil hominins comes from preserved tooth microstructure. A record of incremental growth in enamel and dentine persists, which allows us to reconstruct tooth growth and compare key measures of dental maturation with modern humans and living great apes. Despite their diverse diets and way of life, it is currently difficult to identify any clear differences in the timing of dental development among living great apes, australopiths and the earliest hominins attributed to the genus Homo. There is, however, limited evidence that some early hominins may have attained a greater proportion of their body mass and stature relatively earlier in the growth period than is typical of modern humans today. This article is part of the themed issue ‘Major transitions in human evolution’. PMID:27298465

Factors Related to Sexual Assault Experience among Early Adolescents in Japan

ERIC Educational Resources Information Center

Nagamatsu, Miyuki; Ooshige, Narumi; Goto, Tomoko; Shimazaki, Azusa

2018-01-01

This study examined factors related to sexual assault among early adolescents in Japan. During a 6-month period, an anonymous questionnaire survey was distributed to 1,246 students ages 13-15 years at eight junior high schools. Consent to participation in this study was obtained from a total of 1,125 (90.3%) students. It was found that the…

ENDOCRINE-DISRUPTING CHEMICALS: PREPUBERTAL EXPOSURES AND EFFECTS ON SEXUAL MATURATION AND THYROID FUNCTION IN THE MALE RAT. A FOCUS ON THE EDSTAC RECOMMENDATIONS. ENDOCRINE DISRUPTER SCREENING AND TESTING ADVISORY COMMITTEE

EPA Science Inventory

Endocrine-disrupting chemicals: prepubertal exposures and effects on sexual maturation and thyroid function in the male rat. A focus on the EDSTAC recommendations. Endocrine Disrupter Screening and Testing Advisory Committee.

Stoker TE, Parks LG, Gray LE, Cooper RL.

Arrested development: early prefrontal lesions impair the maturation of moral judgement.

PubMed

Taber-Thomas, Bradley C; Asp, Erik W; Koenigs, Michael; Sutterer, Matthew; Anderson, Steven W; Tranel, Daniel

2014-04-01

Learning to make moral judgements based on considerations beyond self-interest is a fundamental aspect of moral development. A deficit in such learning is associated with poor socialization and criminal behaviour. The neural systems required for the acquisition and maturation of moral competency are not well understood. Here we show in a unique sample of neurological patients that focal lesions involving ventromedial prefrontal cortex, acquired during development, result in an abnormally egocentric pattern of moral judgement. In response to simple hypothetical moral scenarios, the patients were more likely than comparison participants to endorse self-interested actions that involved breaking moral rules or physically harming others in order to benefit themselves. This pattern (which we also found in subjects with psychopathy) differs from that of patients with adult-onset ventromedial prefrontal cortex lesions--the latter group showed normal rejection of egocentric rule violations. This novel contrast of patients with ventromedial prefrontal cortex lesions acquired during development versus during adulthood yields new evidence suggesting that the ventromedial prefrontal cortex is a critical neural substrate for the acquisition and maturation of moral competency that goes beyond self-interest to consider the welfare of others. Disruption to this affective neural system early in life interrupts moral development.

On early starters and late bloomers: the development of sexual behavior in adolescence across personality types.

PubMed

Baams, Laura; Overbeek, Geertjan; Dubas, Judith Semon; van Aken, Marcel A G

2014-01-01

Little is known about the relationship between personality and sexual development among mid-adolescents. In the current study, we used a person-centered approach to investigate the relation between personality types and the development of sexual behavior. We hypothesized that undercontrolling adolescents would engage in more advanced, casual, and risky sexual behavior compared to their resilient and overcontrolling peers. Data were used from 407 mid-adolescents (Mage = 14.5) followed across four measurement waves spanning 18 months. Results from latent class analyses (LCA) identified the three classical personality types: resilients, undercontrollers, and overcontrollers. Controlling for perceived pubertal timing and biological sex, latent growth curve analyses in Mplus showed that, at baseline, undercontrollers were more sexually experienced and engaged in more casual and risky sexual behavior than resilients and overcontrollers. Although initial levels of sexual behavior differed by personality types, over time increases in sexual behavior occurred at a similar rate across the types. Overall, the current study showed that undercontrolling adolescents are early sexual developers who engage in more advanced, casual, and risky sexual behavior than other adolescents. The implications of these findings for longer-term differences in sexual behavior between personality types in later adolescence are discussed.

Alternative life histories in the Atlantic salmon: genetic covariances within the sneaker sexual tactic in males.

PubMed

Páez, David James; Bernatchez, Louis; Dodson, Julian J

2011-07-22

Alternative reproductive tactics are ubiquitous in many species. Tactic expression often depends on whether an individual's condition surpasses thresholds that are responsible for activating particular developmental pathways. Two central goals in understanding the evolution of reproductive tactics are quantifying the extent to which thresholds are explained by additive genetic effects, and describing their covariation with condition-related traits. We monitored the development of early sexual maturation that leads to the sneaker reproductive tactic in Atlantic salmon (Salmo salar L.). We found evidence for additive genetic variance in the timing of sexual maturity (which is a measure of the surpassing of threshold values) and body-size traits. This suggests that selection can affect the patterns of sexual development by changing the timing of this event and/or body size. Significant levels of covariation between these traits also occurred, implying a potential for correlated responses to selection. Closer examination of genetic covariances suggests that the detected genetic variation is distributed along at least five directions of phenotypic variation. Our results show that the potential for evolution of the life-history traits constituting this reproductive phenotype is greatly influenced by their patterns of genetic covariance.

Alternative life histories in the Atlantic salmon: genetic covariances within the sneaker sexual tactic in males

PubMed Central

Páez, David James; Bernatchez, Louis; Dodson, Julian J.

2011-01-01

Alternative reproductive tactics are ubiquitous in many species. Tactic expression often depends on whether an individual's condition surpasses thresholds that are responsible for activating particular developmental pathways. Two central goals in understanding the evolution of reproductive tactics are quantifying the extent to which thresholds are explained by additive genetic effects, and describing their covariation with condition-related traits. We monitored the development of early sexual maturation that leads to the sneaker reproductive tactic in Atlantic salmon (Salmo salar L.). We found evidence for additive genetic variance in the timing of sexual maturity (which is a measure of the surpassing of threshold values) and body-size traits. This suggests that selection can affect the patterns of sexual development by changing the timing of this event and/or body size. Significant levels of covariation between these traits also occurred, implying a potential for correlated responses to selection. Closer examination of genetic covariances suggests that the detected genetic variation is distributed along at least five directions of phenotypic variation. Our results show that the potential for evolution of the life-history traits constituting this reproductive phenotype is greatly influenced by their patterns of genetic covariance. PMID:21177685

Secular changes in body dimensions and sexual maturation in children of Arkhangelsk city.

PubMed

Godina, Elena Z; Khomyakova, Irina A; Zadorozhnaya, Ludmila V

2016-01-01

The aim of the present study was to analyze secular changes in body measurements in children of the Arkhangelsk city from 1988 to 2010. A large number of anthropometric measurements were taken on each individual including height, weight, arm, leg and trunk lengths (estimated), body diameters and circumferences, skinfold thickness. Stages of secondary sex characteristics were also evaluated; data on menarcheal age were collected by status-quo method. It was shown that main differences in stature occurred at puberty while in elder children (16-17-year-olds) no statistically significant differences were found. The same pattern was typical for weight and BMI. Chest circumference significantly increased, particularly in girls. For modern children, changes in body proportions due to a bigger trunk length were typical. There were also significant differences in the distribution of subcutaneous fat layer: in modern children bigger fat accumulation was present on the trunk, particularly in abdomen area, vs. fat layer on the extremities. Process of sexual maturation according to mean ages of development of secondary sex characteristics occurred earlier in modern adolescents, which is more expressed in girls. The results can be interpreted in terms of ongoing secular trend.

Examining negative effects of early life experiences on reproductive and sexual health among female sex workers in Tijuana, Mexico.

PubMed

Oza, Karishma K; Silverman, Jay G; Bojorquez, Ietza; Strathdee, Steffanie A; Goldenberg, Shira M

2015-02-01

To explore experiences during childhood and adolescence that influenced reproductive and sexual health among women who had entered the sex industry in adolescence. A qualitative study was conducted using information provided by 25 female sex workers (FSWs) from Tijuana, Mexico, who reported entering the sex industry when younger than 18 years. In-depth, semi-structured interviews were conducted with all participants between January 31, 2011, and July 8, 2011. Four interrelated themes that shaped health experiences-early sexual abuse, early illicit drug use, ongoing violence, and limited access to reproductive and sexual health care-were identified. Participants reporting these experiences were at risk of unintended teenaged pregnancy, spontaneous abortion or stillbirth, and untreated sexually transmitted infections. Programs and policies that address social, structural, and individual vulnerabilities during adolescence and adulthood are required to promote reproductive and sexual health among FSWs in Tijuana, Mexico. Copyright © 2014 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

Planarian D-amino acid oxidase is involved in ovarian development during sexual induction.

PubMed

Maezawa, Takanobu; Tanaka, Hiroyuki; Nakagawa, Haruka; Ono, Mizuki; Aoki, Manabu; Matsumoto, Midori; Ishida, Tetsuo; Horiike, Kihachiro; Kobayashi, Kazuya

2014-05-01

To elucidate the molecular mechanisms underlying switching from asexual to sexual reproduction, namely sexual induction, we developed an assay system for sexual induction in the hermaphroditic planarian species Dugesia ryukyuensis. Ovarian development is the initial and essential step in sexual induction, and it is followed by the formation of other reproductive organs, including the testes. Here, we report a function of a planarian D-amino acid oxidase, Dr-DAO, in the control of ovarian development in planarians. Asexual worms showed significantly more widespread expression of Dr-DAO in the parenchymal space than did sexual worms. Inhibition of Dr-DAO by RNAi caused the formation of immature ovaries. In addition, we found that feeding asexual worms 5 specific D-amino acids could induce the formation of immature ovaries that are similar to those observed in Dr-DAO knockdown worms, suggesting that Dr-DAO inhibits the formation of immature ovaries by degrading these D-amino acids. Following sexual induction, Dr-DAO expression was observed in the ovaries. The knockdown of Dr-DAO during sexual induction delayed the maturation of the other reproductive organs, as well as ovary. These findings suggest that Dr-DAO acts to promote ovarian maturation and that complete sexual induction depends on the production of mature ovaries. We propose that Dr-DAO produced in somatic cells prevents the onset of sexual induction in the asexual state, and then after sexual induction, the female germ cells specifically produce Dr-DAO to induce full maturation. Therefore, Dr-DAO produced in somatic and female germline cells may play different roles in sexual induction. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Exposure to Childhood Sexual and Physical Abuse and Adjustment in Early Adulthood

ERIC Educational Resources Information Center

Fergusson, David M.; Boden, Joseph M.; Horwood, L. John

2008-01-01

Objective: This research examined linkages between exposure to childhood sexual abuse (CSA) and childhood physical punishment/abuse (CPA) and mental health issues in early adulthood. Method: The investigation analyzed data from a birth cohort of over 1,000 New Zealand young adults studied to the age of 25. Results: Exposure to CSA and CPA was…

Cumulative Risk for Early Sexual Initiation among American Indian Youth: A Discrete-Time Survival Analysis

ERIC Educational Resources Information Center

Mitchell, Christina M.; Whitesell, Nancy Rumbaugh; Spicer, Paul; Beals, Janette; Kaufman, Carol E.

2007-01-01

Approximately 3 million teens are diagnosed with a sexually transmitted disease (STD) annually; STDs rates for American Indian young adults are among the highest of any racial/ethnic group. An important risk factor for STDs is early initiation of sex. In this study, we examined risk for early initiation with 474 American Indian youth ages 14-18,…

Sexual behavior in later life.

PubMed

DeLamater, John; Moorman, Sara M

2007-12-01

This research tests the influences of age, biological, and psychosocial factors on sexual expression in later life. The American Association of Retired Persons Modern Maturity Sexuality Survey collected data on diagnosed illnesses, treated illnesses, sexual desire, sexual attitudes, partner circumstances, and sexual behavior from 1,384 persons ages 45 and older. Ordered logistic regression models estimate the associations of age, biological, and psychosocial factors with the frequency of five sexual behaviors. Diagnosed illnesses and treatments are generally unrelated to frequency of sexual activity. Sexual attitudes are related to frequency of partnered behavior and sexual desire is related to frequency of masturbation among both women and men. Satisfaction with the physical relationship with a partner is strongly related to behavior. Age remains significant after all other factors are controlled. The authors conclude that the nature of sexual expression in later life reflects the interplay of body, mind, and social context.

Early IGF-1 primes visual cortex maturation and accelerates developmental switch between NKCC1 and KCC2 chloride transporters in enriched animals.

PubMed

Baroncelli, Laura; Cenni, Maria Cristina; Melani, Riccardo; Deidda, Gabriele; Landi, Silvia; Narducci, Roberta; Cancedda, Laura; Maffei, Lamberto; Berardi, Nicoletta

2017-02-01

Environmental enrichment (EE) has a remarkable impact on brain development. Continuous exposure to EE from birth determines a significant acceleration of visual system maturation both at retinal and cortical levels. A pre-weaning enriched experience is sufficient to trigger the accelerated maturation of the visual system, suggesting that factors affected by EE during the first days of life might prime visual circuits towards a faster development. The search for such factors is crucial not only to gain a better understanding of the molecular hierarchy of brain development but also to identify molecular pathways amenable to be targeted to correct atypical brain developmental trajectories. Here, we showed that IGF-1 levels are increased in the visual cortex of EE rats as early as P6 and this is a crucial event for setting in motion the developmental program induced by EE. Early intracerebroventricular (i.c.v.) infusion of IGF-1 in standard rats was sufficient to mimic the action of EE on visual acuity development, whereas blocking IGF-1 signaling by i.c.v. injections of the IGF-1 receptor antagonist JB1 prevented the deployment of EE effects. Early IGF-1 decreased the ratio between the expression of NKCC1 and KCC2 cation/chloride transporters, and the reversal potential for GABA A R-driven Cl - currents (E Cl ) was shifted toward more negative potentials, indicating that IGF-1 is a crucial factor in accelerating the maturation of GABAergic neurotransmission and promoting the developmental switch of GABA polarity from excitation to inhibition. In addition, early IGF-1 promoted a later occurring increase in its own expression, suggesting a priming effect of early IGF-1 in driving post-weaning cortical maturation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Beyond Surviving: Gender Differences in Response to Early Sexual Experiences with Adults

ERIC Educational Resources Information Center

Hunter, Sally V.

2009-01-01

The aim of this research project was to explore how men and women constructed a sense of self through narrative following an early sexual experience with an adult. Using narrative inquiry methodology, 22 in-depth interviews were conducted in New South Wales, Australia, with 13 women and 9 men ages between 25 and 70. All participants had an early…

Development of rat female genital cortex and control of female puberty by sexual touch

PubMed Central

Lenschow, Constanze; Sigl-Glöckner, Johanna

2017-01-01

Rat somatosensory cortex contains a large sexually monomorphic genital representation. Genital cortex undergoes an unusual 2-fold expansion during puberty. Here, we investigate genital cortex development and female rat sexual maturation. Ovariectomies and estradiol injections suggested sex hormones cause the pubertal genital cortex expansion but not its maintenance at adult size. Genital cortex expanded by thalamic afferents invading surrounding dysgranular cortex. Genital touch was a dominant factor driving female sexual maturation. Raising female rats in contact with adult males promoted genital cortex expansion, whereas contact to adult females or nontactile (audio-visual-olfactory) male cues did not. Genital touch imposed by human experimenters powerfully advanced female genital cortex development and sexual maturation. Long-term blocking of genital cortex by tetrodotoxin in pubescent females housed with males prevented genital cortex expansion and decelerated vaginal opening. Sex hormones, sexual experience, and neural activity shape genital cortex, which contributes to the puberty promoting effects of sexual touch. PMID:28934203

Development of rat female genital cortex and control of female puberty by sexual touch.

PubMed

Lenschow, Constanze; Sigl-Glöckner, Johanna; Brecht, Michael

2017-09-01

Rat somatosensory cortex contains a large sexually monomorphic genital representation. Genital cortex undergoes an unusual 2-fold expansion during puberty. Here, we investigate genital cortex development and female rat sexual maturation. Ovariectomies and estradiol injections suggested sex hormones cause the pubertal genital cortex expansion but not its maintenance at adult size. Genital cortex expanded by thalamic afferents invading surrounding dysgranular cortex. Genital touch was a dominant factor driving female sexual maturation. Raising female rats in contact with adult males promoted genital cortex expansion, whereas contact to adult females or nontactile (audio-visual-olfactory) male cues did not. Genital touch imposed by human experimenters powerfully advanced female genital cortex development and sexual maturation. Long-term blocking of genital cortex by tetrodotoxin in pubescent females housed with males prevented genital cortex expansion and decelerated vaginal opening. Sex hormones, sexual experience, and neural activity shape genital cortex, which contributes to the puberty promoting effects of sexual touch.

Pre- and Postnatal Nutritional Histories Influence Reproductive Maturation and Ovarian Function in the Rat

PubMed Central

Sloboda, Deborah M.; Howie, Graham J.; Pleasants, Anthony; Gluckman, Peter D.; Vickers, Mark H.

2009-01-01

Background While prepubertal nutritional influences appear to play a role in sexual maturation, there is a need to clarify the potential contributions of maternal and childhood influences in setting the tempo of reproductive maturation. In the present study we employed an established model of nutritional programming to evaluate the relative influences of prenatal and postnatal nutrition on growth and ovarian function in female offspring. Methods Pregnant Wistar rats were fed either a calorie-restricted diet, a high fat diet, or a control diet during pregnancy and/or lactation. Offspring then were fed either a control or a high fat diet from the time of weaning to adulthood. Pubertal age was monitored and blood samples collected in adulthood for endocrine analyses. Results We report that in the female rat, pubertal timing and subsequent ovarian function is influenced by the animal's nutritional status in utero, with both maternal caloric restriction and maternal high fat nutrition resulting in early pubertal onset. Depending on the offspring's nutritional history during the prenatal and lactational periods, subsequent nutrition and body weight gain did not further influence offspring reproductive tempo, which was dominated by the effect of prenatal nutrition. Whereas maternal calorie restriction leads to early pubertal onset, it also leads to a reduction in adult progesterone levels later in life. In contrast, we found that maternal high fat feeding which also induces early maturation in offspring was associated with elevated progesterone concentrations. Conclusions These observations are suggestive of two distinct developmental pathways leading to the acceleration of pubertal timing but with different consequences for ovarian function. We suggest different adaptive explanations for these pathways and for their relationship to altered metabolic homeostasis. PMID:19707592

On Early Starters and Late Bloomers: The Development of Sexual Behavior in Adolescence Across Personality Types

PubMed Central

Overbeek, Geertjan; Dubas, Judith Semon; van Aken, Marcel A. G.

2013-01-01

Little is known about the relationship between personality and sexual development among mid-adolescents. In the current study, we used a person-centered approach to investigate the relation between personality types and the development of sexual behavior. We hypothesized that undercontrolling adolescents would engage in more advanced, casual, and risky sexual behavior compared to their resilient and overcontrolling peers. Data were used from 407 mid-adolescents (Mage = 14.5) followed across four measurement waves spanning 18 months. Results from latent class analyses (LCA) identified the three classical personality types: resilients, undercontrollers, and overcontrollers. Controlling for perceived pubertal timing and biological sex, latent growth curve analyses in Mplus showed that, at baseline, undercontrollers were more sexually experienced and engaged in more casual and risky sexual behavior than resilients and overcontrollers. Although initial levels of sexual behavior differed by personality types, over time increases in sexual behavior occurred at a similar rate across the types. Overall, the current study showed that undercontrolling adolescents are early sexual developers who engage in more advanced, casual, and risky sexual behavior than other adolescents. The implications of these findings for longer-term differences in sexual behavior between personality types in later adolescence are discussed. PMID:24007372

[The maturation steps of human immunodeficiency virus and the role of proteolysis].

PubMed

Bukrinskaia, A G; Grigor'ev, V B; Korablina, E V; Gur'ev, E L; Vorkunova, G K

2010-01-01

HIV-1 virions are as immature noninfectious particles lacking a central core. Shortly after budding, virions temporally mature and acquire cores and infectious activity. The cause of maturation remains poorly studied. We have revealed that the virions produced early after infection following 24-36 hours, never mature and remain noninfectious, and only virions produced 48-72 hours after infection mature. The mature virions contain 3 times more genomic viral RNA than "early" virus. The "early" virions contain the same proteolytically cleaved Gag proteins as mature virions in contrast to the accepted version. The virus protease inhibitor Indinavir sulfate (IS) fully blocks infectivity when added early after infection. The early proteolysis of Gag precursor in the infected cells and inclusion into the virions of cellularly cleaved matrix protein (cMA) are shown in the IS-treated cells. cMA is associated with genomic viral RNA.

The sexually dimorphic cephalofoil of bonnethead sharks, Sphyrna tiburo.

PubMed

Kajiura, Stephen M; Tyminski, John P; Forni, Jesica B; Summers, Adam P

2005-08-01

Sexually dimorphic head shape is common in vertebrates from teleosts to mammals. Herein we document that cephalic sexual dimorphism is also found in the cartilaginous fishes (Chondrichthyes). Male bonnethead sharks develop a prominent bulge along the anterior margin of the cephalofoil at the onset of sexual maturity. This contrasts with the uniformly rounded anterior margin of adult females and juveniles and embryos of both sexes. The anterior cephalic bulge is produced by elongation of the rod-like rostral cartilages, and its appearance corresponds temporally with the elongation of the rod-like cartilages of the male intromittent organs (claspers). We propose that the rostral cartilage elongation is a byproduct of endocrinological changes at the onset of sexual maturity that stimulate growth of the clasper cartilages. The basal location of the chondrichthyan fishes within the vertebrate clade extends the earliest appearance of cephalic sexual dimorphism among the vertebrates.

Relation of adrenal-derived steroids with bone maturation, mineral density and geometry in healthy prepubertal and early pubertal boys.

PubMed

Vandewalle, S; Taes, Y; Fiers, T; Toye, K; Van Caenegem, E; Kaufman, J-M; De Schepper, J

2014-12-01

Little is known about the effects of adrenal steroids on skeletal maturation and bone mass acquisition in healthy prepubertal boys. To study whether adrenal-derived steroids within the physiological range are associated with skeletal maturation, areal and volumetric bone mineral density (aBMD and vBMD) and bone geometry in healthy prepubertal and early pubertal boys. 98 healthy prepubertal and early pubertal boys (aged 6-14 y) were studied cross-sectionally. Androstenedione (A) and estrone (E1) were determined by liquid chromatography tandem mass spectrometry and DHEAS was determined by immunoassay. Whole body and lumbar spine aBMD and bone area were determined by dual-energy X-ray absorptiometry. Trabecular (distal site) and cortical (proximal site) vBMD and bone geometry were assessed at the non-dominant forearm and leg using peripheral QCT. Skeletal age was determined by X-ray of the left hand. Adrenal-derived steroids (DHEAS, A and E1) are positively associated with bone age in prepubertal and early pubertal children, independently of age. There are no associations between the adrenal-derived steroids and the studied parameters of bone size (lumbar spine and whole body bone area, trabecular or cortical area at the radius or tibia, periosteal circumference and cortical thickness at the radius or tibia) or BMD (aBMD or vBMD). In healthy prepubertal and early pubertal boys, serum adrenal-derived steroid levels, are associated with skeletal maturation, independently of age, but not with bone size or (v)BMD. Our data suggest that adrenal derived steroids are not implicated in the accretion of bone mass before puberty in boys. Copyright © 2014 Elsevier Inc. All rights reserved.

The sexual cascade and the rise of pre-ejaculatory (Darwinian) sexual selection, sex roles, and sexual conflict.

PubMed

Parker, Geoff A

2014-08-21

After brief historic overviews of sexual selection and sexual conflict, I argue that pre-ejaculatory sexual selection (the form of sexual selection discussed by Darwin) arose at a late stage in an inevitable succession of transitions flowing from the early evolution of syngamy to the evolution of copulation and sex roles. If certain conditions were met, this "sexual cascade" progressed inevitably, if not, sexual strategy remained fixed at a given stage. Prolonged evolutionary history of intense sperm competition/selection under external fertilization preceded the rise of advanced mobility, which generated pre-ejaculatory sexual selection, followed on land by internal fertilization and reduced sperm competition in the form of postcopulatory sexual selection. I develop a prospective model of the early evolution of mobility, which, as Darwin realized, was the catalyst for pre-ejaculatory sexual selection. Stages in the cascade should be regarded as consequential rather than separate phenomena and, as such, invalidate much current opposition to Darwin-Bateman sex roles. Potential for sexual conflict occurs throughout, greatly increasing later in the cascade, reaching its peak under precopulatory sexual selection when sex roles become highly differentiated. Copyright © 2014 Cold Spring Harbor Laboratory Press; all rights reserved.

The Sexual Cascade and the Rise of Pre-Ejaculatory (Darwinian) Sexual Selection, Sex Roles, and Sexual Conflict

PubMed Central

Parker, Geoff A.

2014-01-01

After brief historic overviews of sexual selection and sexual conflict, I argue that pre-ejaculatory sexual selection (the form of sexual selection discussed by Darwin) arose at a late stage in an inevitable succession of transitions flowing from the early evolution of syngamy to the evolution of copulation and sex roles. If certain conditions were met, this “sexual cascade” progressed inevitably, if not, sexual strategy remained fixed at a given stage. Prolonged evolutionary history of intense sperm competition/selection under external fertilization preceded the rise of advanced mobility, which generated pre-ejaculatory sexual selection, followed on land by internal fertilization and reduced sperm competition in the form of postcopulatory sexual selection. I develop a prospective model of the early evolution of mobility, which, as Darwin realized, was the catalyst for pre-ejaculatory sexual selection. Stages in the cascade should be regarded as consequential rather than separate phenomena and, as such, invalidate much current opposition to Darwin–Bateman sex roles. Potential for sexual conflict occurs throughout, greatly increasing later in the cascade, reaching its peak under precopulatory sexual selection when sex roles become highly differentiated. PMID:25147177

Understanding Early Sexual Development (For Parents)

MedlinePlus

... Your preschooler will continue to learn important sexual attitudes from you — from how you react to people ... begin to have a bigger influence on sexual attitudes. If you aren't a reliable resource, your ...

Influence of breeding habitat on bear predation and age at maturity and sexual dimorphism of sockeye salmon populations

USGS Publications Warehouse

Quinn, Thomas P.; Wetzel, Lisa A.; Bishop, Susan; Overberg, Kristi; Rogers, Donald E.

2001-01-01

Age structure and morphology differ among Pacific salmon (Oncorhynchus spp.) populations. Sexual selection and reproductive capacity (fecundity and egg size) generally favor large (old), deep-bodied fish. We hypothesized that natural selection from physical access to spawning grounds and size-biased predation by bears, Ursus spp., opposes such large, deep-bodied salmon. Accordingly, size and shape of salmon should vary predictably among spawning habitats. We tested this hypothesis by measuring the age composition and body depth of sockeye salmon, Oncorhynchus nerka, and the intensity of predation in a range of breeding habitats in southwestern Alaska. Stream width was positively correlated with age at maturity and negatively correlated with predation level. However, salmon spawning on lake beaches were not consistently old, indicating that different factors affect age in riverine- and beach-spawning populations. Body depths of male and female salmon were positively correlated with water depth across all sites, as predicted. However, the mouths of some streams were so shallow that they might select against large or deep-bodied salmon, even in the absence of bear predation. Taken together, the results indicated that habitat has direct and indirect effects (via predation) on life history and morphology of mature salmon.

Detailed educational pathways among females after very early sexual intercourse.

PubMed

Steward, Nicole R; Farkas, George; Bingenheimer, Jeffrey B

2009-12-01

Although studies have shown that early sex is negatively associated with high school graduation and college enrollment, no recent study has examined the extent to which early sex affects educational attainment, and the mediating mechanisms have not been established. Data from 4,613 female participants in the National Educational Longitudinal Study were used to examine the relationship between early sexual intercourse (i.e., first sex prior to age 15) and educational attainment. Logistic regression analyses that controlled for background characteristics, school performance, behavioral factors and academic aspirations were conducted to assess this association, as well as to explore the potential mediating role of early marriage and childbearing. Young women who had had early sex had reduced odds of having graduated from high school (odds ratio, 0.4) and from college (0.5). Postsecondary enrollment was positively associated with expectations of postsecondary education (1.5) and levels of academic achievement (1.4-1.5), but not with early sex. Respondents who had married before their expected high school graduation date had reduced odds of having graduated from high school (0.1), enrolled in postsecondary school (0.4) or completed college (0.1); those who had a child before their expected high school graduation date had reduced odds of having graduated from high school (0.3) or college (0.1). Programs that target early parenthood and marriage, and that provide hope for future educational opportunities, could lessen the impact of early sex for young women.

Buffer or Brake? The Role of Sexuality-Specific Parenting in Adolescents' Sexualized Media Consumption and Sexual Development.

PubMed

Overbeek, Geertjan; van de Bongardt, Daphne; Baams, Laura

2018-03-13

brake adolescents' move toward sexual maturity.

The acceleration of the masculine in early-twentieth-century Berlin.

PubMed

Prickett, David James

2012-01-01

In early-twentieth-century Berlin, agents of speed and industrialisation, such as the railway, contributed to the seemingly unbridled velocity of urban life. Doctors and cultural critics took an ambivalent stance toward the impact of speed and technology on the human body. Critics argued that these factors, in conjunction with sexual excess and prostitution, accelerated the sexual maturation of young men, thereby endangering ‘healthy’ male sexuality. This comparison of Hans Ostwald's socio-literary study Dunkle Winkel in Berlin (1904) with Georg Buschan's sexual education primer Vom Jüngling zum Mann (1911) queries the extent to which speed shaped the understanding of ‘the masculine’ in pre-World-War-I Germany. The essay thus examines Ostwald's and Buschan's arguments and postulates that speed in the city (Berlin) can be seen as a feminised, sexualised force that determined sex in the city. According to this reading, the homosexual urban dandy resisted the accelerated modernist urban tempo, whereas the heterosexual man and hegemonic, heteronormative masculinity yielded to speed. ‘“Das Verhältnis”’ became a fleeting, momentary alternative to stable marital relationships, which in turn contributed to the general ‘crisis’ of – and in– masculinity in early-twentieth-century Berlin.

Sexual maturation and fertility of male Nigerian Dwarf goat (Capra hircus) clones produced by somatic cell nuclear transfer.

PubMed

Gauthier, M; Pierson, J; Drolet, M; Bhatia, B; Baldassarre, H; Keefer, C L

2001-01-01

Three, genetically identical, Nigerian Dwarf bucks produced by somatic cell nuclear transfer (NT) of fetal fibroblasts were monitored for sexual maturation and fertility. Starting at four months of age, these male clones were trained to serve an artificial vagina (AV). Average age of the NT-derived bucks at first semen collection was 20 weeks, which was not different from that of other young bucks of this breed (average age at first collection = 20 weeks). Average sperm production at 5 months of age for the NT-derived bucks was 5.0 x 10(8) spermatozoa, which was comparable to that of dwarf bucks of similar age (3.4 x 10(8) spermatozoa). At seven months of age, semen collected from two NT-derived bucks was used to artificially inseminate six females (three does per buck). Five does were confirmed pregnant by ultrasound at day 42. Nine healthy kids, four males and five females, were born in March and April 2000. Viable spermatozoa were collected from one of the F1 males at 28 weeks of age. These results demonstrated that NT-derived bucks and one of their male offspring developed sexually within the normal timeframe for their breed and that the clones were fertile.

Maturation of Black Cherry Fruits in Central Mississippi

Treesearch

F.T. Bonner

1975-01-01

Black cherry (Prunus serotina Ehrh.) in central Mississippi grew in size and weight from early May until maturity in late June. In early June, crude fat, protein-nitrogen, and calcium concentrations increased; moisture content decreased; endocarps hardened; and embryo tissues became firm. From mid-June to maturity mesocarp growth was prominent as...

Overwinter survival of neotropical migratory birds in early successional and mature tropical forests

USGS Publications Warehouse

Conway, C.J.; Powell, G.V.N.; Nichols, J.D.

1995-01-01

Many Neotropical migratory species inhabit both mature and early successional forest on their wintering grounds, yet comparisons of survival rates between habitats are lacking. Consequently, the factors affecting habitat suitability for Neotropical migrants and the potential effects of tropical deforestation on migrants are not well understood. We estimated over-winter survival and capture probabilities of Wood Thrush (Hylocichla mustelina), Ovenbird (Seiurus aurocapillus), Hooded Warbler (Wilsonia citrina), and Kentucky Warbler (Oporomis formosus) inhabiting two common tropical habitat types, mature and early-successional forest. Our results suggest that large differences (for example, ratio of survival rates (gamma) < 0.85) in overwinter survival between these habitats do not exist for any of these species. Age ratios did not differ between habitats, but males were more common in forest habitats and females more common in successional habitats for Hooded Warblers and Kentucky Warblers. Future research on overwinter survival should address the need for age- and sex-specific survival estimates before we can draw strong conclusions regarding winter habitat suitability. Our estimates of over-winter survival extrapolated to annual survival rates that were generally lower than previous estimates of annual survival of migratory birds. Capture probability differed between habitats for Kentucky Warblers, but our results provide strong evidence against large differences in capture probability between habitats for Wood Thrush, Hooded Warblers, and Ovenbirds. We found no temporal or among site differences in survival or capture probability for any of the four species. Additional research is needed to examine the effects of winter habitat use on survival during migration and between-winter survival.

Relationships of parental monitoring and emotion regulation with early adolescents' sexual behaviors.

PubMed

Hadley, Wendy; Houck, Christopher D; Barker, David; Senocak, Natali

2015-06-01

The purpose of this study was to examine the moderating influence of parental monitoring (e.g., unsupervised time with opposite sex peers) and adolescent emotional competence on sexual behaviors, among a sample of at-risk early adolescents. This study included 376 seventh-grade adolescents (age, 12-14 years) with behavioral or emotional difficulties. Questionnaires were completed on private laptop computers and assessed adolescent Emotional Competence (including Regulation and Negativity/Lability), Unsupervised Time, and a range of Sexual Behaviors. Generalized linear models were used to evaluate the independent and combined influence of Emotional Competency and Unsupervised Time on adolescent report of Sexual Behaviors. Analyses were stratified by gender to account for the notable gender differences in the targeted moderators and outcome variables. Findings indicated that more unsupervised time was a risk factor for all youth but was influenced by an adolescent's ability to regulate their emotions. Specifically, for males and females, poorer Emotion Regulation was associated with having engaged in a greater variety of Sexual Behaviors. However, lower Negativity/Lability and >1× per week Unsupervised Time were associated with a higher number of sexual behaviors among females only. Based on the findings of this study, a lack of parental supervision seems to be particularly problematic for both male and female adolescents with poor emotion regulation abilities. It may be important to impact both emotion regulation abilities and increase parental knowledge and skills associated with effective monitoring to reduce risk-taking for these youth.

Adolescent sexuality.

PubMed

Grant, L M; Demetriou, E

1988-12-01

The consequences of adolescent sexual behavior are an enormous burden both for the adolescent and society. The problem is not that teens are sexually active but rather that they have little preparation and guidance in developing responsible sexual behavior. Developmentally, adolescents reach physical maturity before they are cognitively able to appreciate the consequences of their behavior. A teenager's primary source of information regarding sexuality is his or her peer group, all of whom are experiencing and reinforcing the same behaviors. The family, the major socializer of other behaviors, is not as powerful a force in shaping responsible sexual behavior because of parental discomfort with sex education and sexual discussions. This is the result of a social milieu in which sex is frequently portrayed but rarely linked with responsible behavior or accurate, nonjudgmental information. The pediatric practitioner is in an ideal position to intervene in these dynamics. In the office, the practitioner can provide accurate sexual information to both parents and adolescents, support parental-child communication on sexual issues, and provide appropriate services or referral. In the community, the practitioner can advocate for school-based sex education as well as act as an information resource. Finally, the practitioner can advocate for the health care needs for adolescents on a national level, supporting legislation that provides adolescents with information and access to services necessary to make responsible sexual decisions.

Early Cannabis Use, Polygenic Risk Score for Schizophrenia and Brain Maturation in Adolescence.

PubMed

French, Leon; Gray, Courtney; Leonard, Gabriel; Perron, Michel; Pike, G Bruce; Richer, Louis; Séguin, Jean R; Veillette, Suzanne; Evans, C John; Artiges, Eric; Banaschewski, Tobias; Bokde, Arun W L; Bromberg, Uli; Bruehl, Ruediger; Buchel, Christian; Cattrell, Anna; Conrod, Patricia J; Flor, Herta; Frouin, Vincent; Gallinat, Jurgen; Garavan, Hugh; Gowland, Penny; Heinz, Andreas; Lemaitre, Herve; Martinot, Jean-Luc; Nees, Frauke; Orfanos, Dimitri Papadopoulos; Pangelinan, Melissa Marie; Poustka, Luise; Rietschel, Marcella; Smolka, Michael N; Walter, Henrik; Whelan, Robert; Timpson, Nic J; Schumann, Gunter; Smith, George Davey; Pausova, Zdenka; Paus, Tomáš

2015-10-01

Cannabis use during adolescence is known to increase the risk for schizophrenia in men. Sex differences in the dynamics of brain maturation during adolescence may be of particular importance with regard to vulnerability of the male brain to cannabis exposure. To evaluate whether the association between cannabis use and cortical maturation in adolescents is moderated by a polygenic risk score for schizophrenia. Observation of 3 population-based samples included initial analysis in 1024 adolescents of both sexes from the Canadian Saguenay Youth Study (SYS) and follow-up in 426 adolescents of both sexes from the IMAGEN Study from 8 European cities and 504 male youth from the Avon Longitudinal Study of Parents and Children (ALSPAC) based in England. A total of 1577 participants (aged 12-21 years; 899 [57.0%] male) had (1) information about cannabis use; (2) imaging studies of the brain; and (3) a polygenic risk score for schizophrenia across 108 genetic loci identified by the Psychiatric Genomics Consortium. Data analysis was performed from March 1 through December 31, 2014. Cortical thickness derived from T1-weighted magnetic resonance images. Linear regression tests were used to assess the relationships between cannabis use, cortical thickness, and risk score. Across the 3 samples of 1574 participants, a negative association was observed between cannabis use in early adolescence and cortical thickness in male participants with a high polygenic risk score. This observation was not the case for low-risk male participants or for the low- or high-risk female participants. Thus, in SYS male participants, cannabis use interacted with risk score vis-à-vis cortical thickness (P = .009); higher scores were associated with lower thickness only in males who used cannabis. Similarly, in the IMAGEN male participants, cannabis use interacted with increased risk score vis-à-vis a change in decreasing cortical thickness from 14.5 to 18.5 years of age (t137 = -2.36; P�

Early Cannabis Use, Polygenic Risk Score for Schizophrenia, and Brain Maturation in Adolescence

PubMed Central

French, Leon; Gray, Courtney; Leonard, Gabriel; Perron, Michel; Pike, G. Bruce; Richer, Louis; Séguin, Jean R.; Veillette, Suzanne; Evans, C. John; Artiges, Eric; Banaschewski, Tobias; Bokde, Arun W. L.; Bromberg, Uli; Bruehl, Ruediger; Buchel, Christian; Cattrell, Anna; Conrod, Patricia J.; Flor, Herta; Frouin, Vincent; Gallinat, Jurgen; Garavan, Hugh; Gowland, Penny; Heinz, Andreas; Lemaitre, Herve; Martinot, Jean-Luc; Nees, Frauke; Orfanos, Dimitri Papadopoulos; Pangelinan, Melissa Marie; Poustka, Luise; Rietschel, Marcella; Smolka, Michael N.; Walter, Henrik; Whelan, Robert; Timpson, Nic J.; Schumann, Gunter; Smith, George Davey; Pausova, Zdenka; Paus, Tomáš

2016-01-01

IMPORTANCE Cannabis use during adolescence is known to increase the risk for schizophrenia in men. Sex differences in the dynamics of brain maturation during adolescence may be of particular importance with regard to vulnerability of the male brain to cannabis exposure. OBJECTIVE To evaluate whether the association between cannabis use and cortical maturation in adolescents is moderated by a polygenic risk score for schizophrenia. DESIGN, SETTING, AND PARTICIPANTS Observation of 3 population-based samples included initial analysis in 1024 adolescents of both sexes from the Canadian Saguenay Youth Study (SYS) and follow-up in 426 adolescents of both sexes from the IMAGEN Study from 8 European cities and 504 male youth from the Avon Longitudinal Study of Parents and Children (ALSPAC) based in England. A total of 1577 participants (aged 12–21 years; 899 [57.0%] male) had (1) information about cannabis use; (2) imaging studies of the brain; and (3) a polygenic risk score for schizophrenia across 108 genetic loci identified by the Psychiatric Genomics Consortium. Data analysis was performed from March 1 through December 31, 2014. MAIN OUTCOMES AND MEASURES Cortical thickness derived from T1-weighted magnetic resonance images. Linear regression tests were used to assess the relationships between cannabis use, cortical thickness, and risk score. RESULTS Across the 3 samples of 1574 participants, a negative association was observed between cannabis use in early adolescence and cortical thickness in male participants with a high polygenic risk score. This observation was not the case for low-risk male participants or for the low- or high-risk female participants. Thus, in SYS male participants, cannabis use interacted with risk score vis-à-vis cortical thickness (P = .009); higher scores were associated with lower thickness only in males who used cannabis. Similarly, in the IMAGEN male participants, cannabis use interacted with increased risk score vis-à-vis a change in

Experience of Sexual Abuse in Childhood and Abortion in Adolescence and Early Adulthood

ERIC Educational Resources Information Center

Boden, Joseph M.; Fergusson, David M.; Horwood, L. John

2009-01-01

Objective: The present study examined the associations between the experience of sexual abuse in childhood (CSA) and the number of abortions in adolescence and early adulthood. Method: A 25-year prospective longitudinal study of the health, development, and adjustment of a birth cohort of 1,265 New Zealand children (630 females). Measures included…

Specificity of early movie effects on adolescent sexual behavior and alcohol use.

PubMed

O'Hara, Ross E; Gibbons, Frederick X; Li, Zhigang; Gerrard, Meg; Sargent, James D

2013-11-01

Adolescents' movie sex exposure (MSE) and movie alcohol exposure (MAE) have been shown to influence later sexual behavior and drinking, respectively. No study to date, however, has tested whether these effects generalize across behaviors. This study examined the concurrent influences of early (i.e., before age 16) MSE and MAE on subsequent risky sex and alcohol use among a national sample of 1228 U.S. adolescents. Participants reported their health behaviors and movie viewing up to six times between 2003 and 2009 in telephone interviews. The Beach method was used to create a population-based estimate of each participant's MSE and MAE, which were then entered into a structural equation model (SEM) to predict lifetime risky sex and past month alcohol use at ages 18-21. For both men and women, MAE predicted alcohol use, mediated by age of initiation of heavy episodic drinking (HED) and age of sexual debut; MAE also predicted risky sex via age of sexual debut. Among men only, MSE indirectly predicted risky sex and alcohol use. Findings indicated that early exposure to risk content from movies had both specific and general effects on later risk-taking, but gender differences were evident: for men, MSE was a stronger predictor than MAE, but for women, only MAE predicted later risk behavior. These results have implications for future media research, prevention programs for adolescent sex and alcohol use, and movie ratings that can guide parents' decisions as to which movies are appropriate for their children. Copyright © 2013 Elsevier Ltd. All rights reserved.

Specificity of Early Movie Effects on Adolescent Sexual Behavior and Alcohol Use

PubMed Central

O’Hara, Ross E.; Gibbons, Frederick X.; Li, Zhigang; Gerrard, Meg; Sargent, James D.

2013-01-01

Adolescents’ movie sex exposure (MSE) and movie alcohol exposure (MAE) have been shown to influence later sexual behavior and drinking, respectively. No study to date, however, has tested whether these effects generalize across behaviors. This study examined the concurrent influences of early (i.e., before age 16) MSE and MAE on subsequent risky sex and alcohol use among a national sample of 1,228 U.S. adolescents. Participants reported their health behaviors and movie viewing up to six times between 2003 and 2009 in telephone interviews. The Beach method was used to create a population-based estimate of each participant’s MSE and MAE, which were then entered into a structural equation model (SEM) to predict lifetime risky sex and past month alcohol use at ages 18–21. For both men and women, MAE predicted alcohol use, mediated by age of initiation of heavy episodic drinking (HED) and age of sexual debut; MAE also predicted risky sex via age of sexual debut. Among men only, MSE indirectly predicted risky sex and alcohol use. Findings indicated that early exposure to risk content from movies had both specific and general effects on later risk-taking, but gender differences were evident: for men, MSE was a stronger predictor than MAE, but for women, only MAE predicted later risk behavior. These results have implications for future media research, prevention programs for adolescent sex and alcohol use, and movie ratings that can guide parents’ decisions as to which movies are appropriate for their children. PMID:24034968

Hormonal changes accompanying sexual maturation in captive milkfish (Chanos chanos Forsskal).

PubMed

Marte, C L; Lam, T J

1992-12-01

Steroid hormone profiles accompanying sexual maturation in captive milkfish are described. There were no significant differences in levels of serum estradiol 17-β (E2) and testosterone (T) between immature male and female fish. Mean E2 levels rose from 0.54±0.11 ng/ml in immature females (Stage 1) to 4.53±1.16 ng/ml in vitellogenic females (Stage 5), while T levels increased from 2.06±0.28 ng/ml to 38.4±9.26 ng/ml. E2 and T levels were positively correlated to GSI and oocyte diameter. In males, serum T levels increased from 2.5±0.40 ng/ml in immature males to 27.73±5.02 ng/ml in spermiating males. A significantly higher T level was found in males with thick and scantly milt (spermiation index, SPI, 2) compared to males with scanty milt (SPI, 1) or males with copious, fluid milt (SPI, 3).Serum levels of E2 and T, and the GSI in females rose significantly during the breeding season (April-June 1983). The levels of both steroids dropped below 1 ng/ml in spent females sampled in succeeding months. In immature males, T levels ranged from 1.11 ng/ml to 2.78 ng/ml and rose significantly to 21.52±8.38 ng/ml during the breeding season when GSI peaked. Serum T levels dropped to around 10 ng/ml in the succeeding months when only spent or regressed males were sampled.

Ion currents involved in oocyte maturation, fertilization and early developmental stages of the ascidian Ciona intestinalis.

PubMed

Tosti, Elisabetta; Gallo, Alessandra; Silvestre, Francesco

2011-01-01

Electrophysiological techniques were used to study the role of ion currents in the ascidian Ciona intestinalis oocyte plasma membrane during different stages of growth, meiosis, fertilization and early development. Three stages of immature oocytes were discriminated in the ovary, with the germinal vesicle showing specific different features of growth and maturation. Stage-A (pre-vitellogenic) oocytes exhibited the highest L-type calcium current activity and were incompetent for meiosis resumption. Stage-B (vitellogenic) oocytes showed a progressive disappearance of calcium currents and the first appearance of sodium currents that remained high during the maturation process, up to the post-vitellogenic stage-C oocytes. The latter had acquired meiotic competence, undergoing spontaneous in vitro maturation and interacting with the spermatozoon. However, fertilized oocytes did not produce normal larvae, suggesting that cytoplasmic maturation may affect embryo development. In mature oocytes at the metaphase I stage, sodium currents were present and remained high up to the zygote stage. Oocytes fertilized in the absence of sodium showed significant reduction of the fertilization current amplitude and high development of anomalous "rosette" embryos. Current amplitudes became negligible in embryos at the 2- and 4-cell stage, whereas resumption of all the current activities occurred at the 8-cell embryo. Taken together, these results suggest: (i) an involvement of L-type calcium currents in initial oocyte meiotic progression and growth; (ii) a role of sodium currents at fertilization; (iii) a role of the fertilization current in ensuring normal embryo development. Copyright © 2011 Wiley Periodicals, Inc.

Relative Skeletal Maturation and Population Ancestry in Nonobese Children and Adolescents

PubMed Central

McCormack, Shana E; Chesi, Alessandra; Mitchell, Jonathan A; Roy, Sani M; Cousminer, Diana L; Kalkwarf, Heidi J; Lappe, Joan M; Gilsanz, Vicente; Oberfield, Sharon E; Shepherd, John A; Mahboubi, Soroosh; Winer, Karen K; Kelly, Andrea; Grant, Struan FA; Zemel, Babette S

2017-01-01

More rapid skeletal maturation in African-American (AA) children is recognized and generally attributed to an increased prevalence of obesity. The objective of the present study was to evaluate the effects of population ancestry on relative skeletal maturation in healthy, non-obese children and adolescents, accounting for body composition and sexual maturation. To do this, we leveraged a multiethnic, mixed-longitudinal study with annual assessments for up to 7 years (The Bone Mineral Density in Childhood Study and its ancillary cohort) conducted at five US clinical centers. Participants included 1592 children, skeletally immature (45% females, 19% AA) who were aged 5 to 17 years at study entry. The primary outcome measure was relative skeletal maturation as assessed by hand-wrist radiograph. Additional covariates measured included anthropometrics, body composition by dual-energy X-ray absorptiometry (DXA), and Tanner stage of sexual maturation. Using mixed effects longitudinal models, without covariates, advancement in relative skeletal maturation was noted in self-reported AA girls (~0.33 years, p<0.001) and boys (~0.43 years, p<0.001). Boys and girls of all ancestry groups showed independent positive associations of height, lean mass, fat mass, and puberty with relative skeletal maturation. The effect of ancestry was attenuated but persistent after accounting for covariates: for girls, 0.12 years (ancestry by self-report, p = 0.12) or 0.29 years (ancestry by admixture, p = 0.004); and for boys, 0.20 years (ancestry by self-report, p = 0.0038) or 0.29 years (ancestry by admixture, p = 0.004). In summary, we conclude that advancement in relative skeletal maturation was associated with AA ancestry in healthy, non-obese children, independent of growth, body composition, and puberty. Further research into the mechanisms underlying this observation may provide insights into the regulation of skeletal maturation. PMID:27419386

Gut microbial functional maturation and succession during human early life.

PubMed

Cerdó, Tomás; Ruiz, Alicia; Acuña, Inmaculada; Jáuregui, Ruy; Jehmlich, Nico; Haange, Sven-Bastian; von Bergen, Martin; Suárez, Antonio; Campoy, Cristina

2018-04-24

The evolutional trajectory of gut microbial colonization from birth has been shown to prime for health later in life. Here, we combined cultivation-independent 16S rRNA gene sequencing and metaproteomics to investigate the functional maturation of gut microbiota in faecal samples from full-term healthy infants collected at 6 and 18 months of age. Phylogenetic analysis of the metaproteomes showed that Bifidobacterium provided the highest number of distinct protein groups. Considerable divergences between taxa abundance and protein phylogeny were observed at all taxonomic ranks. Age had a profound effect on early microbiota where compositional and functional diversity of less dissimilar communities increased with time. Comparisons of the relative abundances of proteins revealed the transition of taxon-associated saccharolytic and fermentation strategies from milk and mucin-derived monosaccharide catabolism feeding acetate/propanoate synthesis to complex food-derived hexoses fuelling butanoate production. Furthermore, co-occurrence network analysis uncovered two anti-correlated modules of functional taxa. A low-connected Bifidobacteriaceae-centred guild of facultative anaerobes was succeeded by a rich club of obligate anaerobes densely interconnected around Lachnospiraceae, underpinning their pivotal roles in microbial ecosystem assemblies. Our findings establish a framework to visualize whole microbial community metabolism and ecosystem succession dynamics, proposing opportunities for microbiota-targeted health-promoting strategies early in life. © 2018 Society for Applied Microbiology and John Wiley & Sons Ltd.

Chronic social stress in puberty alters appetitive male sexual behavior and neural metabolic activity.

PubMed

Bastida, Christel C; Puga, Frank; Gonzalez-Lima, Francisco; Jennings, Kimberly J; Wommack, Joel C; Delville, Yvon

2014-07-01

Repeated social subjugation in early puberty lowers testosterone levels. We used hamsters to investigate the effects of social subjugation on male sexual behavior and metabolic activity within neural systems controlling social and motivational behaviors. Subjugated animals were exposed daily to aggressive adult males in early puberty for postnatal days 28 to 42, while control animals were placed in empty clean cages. On postnatal day 45, they were tested for male sexual behavior in the presence of receptive female. Alternatively, they were tested for mate choice after placement at the base of a Y-maze containing a sexually receptive female in one tip of the maze and an ovariectomized one on the other. Social subjugation did not affect the capacity to mate with receptive females. Although control animals were fast to approach females and preferred ovariectomized individuals, subjugated animals stayed away from them and showed no preference. Cytochrome oxidase activity was reduced within the preoptic area and ventral tegmental area in subjugated hamsters. In addition, the correlation of metabolic activity of these areas with the bed nucleus of the stria terminalis and anterior parietal cortex changed significantly from positive in controls to negative in subjugated animals. These data show that at mid-puberty, while male hamsters are capable of mating, their appetitive sexual behavior is not fully mature and this aspect of male sexual behavior is responsive to social subjugation. Furthermore, metabolic activity and coordination of activity in brain areas related to sexual behavior and motivation were altered by social subjugation. Copyright © 2014 Elsevier Inc. All rights reserved.

Chronic Social Stress in Puberty Alters Appetitive Male Sexual Behavior and Neural Metabolic Activity

PubMed Central

Bastida, Christel C.; Puga, Frank; Gonzalez-Lima, Francisco; Jennings, Kimberly J.; Wommack, Joel C.; Delville, Yvon

2014-01-01

Repeated social subjugation in early puberty lowers testosterone levels. We used hamsters to investigate the effects of social subjugation on male sexual behavior and metabolic activity within neural systems controlling social and motivational behaviors. Subjugated animals were exposed daily to aggressive adult males in early puberty for postnatal days 28 to 42, while control animals were placed in empty clean cages. On postnatal day 45, they were tested for male sexual behavior in the presence of receptive female. Alternatively, they were tested for mate choice after placement at the base of a Y-maze containing a sexually receptive female in one tip of the maze and an ovariectomized one on the other. Social subjugation did not affect the capacity to mate with receptive females. Although control animals were fast to approach females and preferred ovariectomized individuals, subjugated animals stayed away from them and showed no preference. Cytochrome oxidase activity was reduced within the preoptic area and ventral tegmental area in subjugated hamsters. In addition, the correlation of metabolic activity of these areas with the bed nucleus of the stria terminalis and anterior parietal cortex changed significantly from positive in controls to negative in subjugated animals. These data show that at mid-puberty, while male hamsters are capable of mating, their appetitive sexual behavior is not fully mature and this aspect of male sexual behavior is responsive to social subjugation. Furthermore, metabolic activity and coordination of activity in brain areas related to sexual behavior and motivation was altered by social subjugation. PMID:24852486

Shape, size, and maturity trajectories of the human ilium.

PubMed

Wilson, Laura A B; Ives, Rachel; Cardoso, Hugo F V; Humphrey, Louise T

2015-01-01

Morphological traits of the ilium have consistently been more successful for juvenile sex determination than have techniques applied to other skeletal elements, however relatively little is known about the ontogeny and maturation of size and shape dimorphism in the ilium. We use a geometric morphometric approach to quantitatively separate the ontogeny of size and shape of the ilium, and analyze interpopulation differences in the onset, rate and patterning of sexual dimorphism. We captured the shape of three traits for a total of 191 ilia from Lisbon (Portugal) and London (UK) samples of known age and sex (0-17 years). Our results indicate that a) there is a clear dissociation between the ontogeny of size and shape in males and females, b) the ontogeny of size and shape are each defined by non-linear trajectories that differ between the sexes, c) there are interpopulation differences in ontogenetic shape trajectories, which point to population-specific patterning in the attainment of sexual dimorphism, and d) the rate of shape maturation and size maturation is typically higher for females than males. Male and female shape differences in the ilium are brought about by trajectory divergence. Differences in size and shape maturation between the sexes suggest that maturity may confound our ability to discriminate between the sexes by introducing variation not accounted for in age-based groupings. The accuracy of sex determination methods using the ilium may be improved by the use of different traits for particular age groups, to capture the ontogenetic development of shape in both sexes. © 2014 Wiley Periodicals, Inc.

Neighborhood poverty and early transition to sexual activity in young adolescents: a developmental ecological approach.

PubMed

Dupéré, Véronique; Lacourse, Eric; Willms, J Douglas; Leventhal, Tama; Tremblay, Richard E

2008-01-01

This study examined how the link between neighborhood poverty and the timing of sexual initiation varies as a function of age, gender, and background characteristics. A sample of N = 2,596 predominately White Canadian adolescents from the National Longitudinal Survey of Children and Youth was used. Sexual initiations occurring between 12 and 15 years old were considered. Results showed that younger adolescent females who lived in poor neighborhoods and who had a history of conduct problems were more likely to report early sexual activity. Peer characteristics partly accounted for this susceptibility. Among adolescent males, no direct neighborhood effects were found, but those who had combined risks at multiple levels appeared more vulnerable. The theoretical and practical implications of these findings are discussed.

SHIP-1 Increases Early Oxidative Burst and Regulates Phagosome Maturation in Macrophages1

PubMed Central

Kamen, Lynn A.; Levinsohn, Jonathan; Cadwallader, Amy; Tridandapani, Susheela; Swanson, Joel A.

2010-01-01

Although the inositol phosphatase SHIP-1 is generally thought to inhibit signaling for Fc receptor-mediated phagocytosis, the product of its activity, phosphatidylinositol 3,4 bisphosphate (PI(3,4)P2) has been implicated in activation of the NADPH oxidase. This suggests that SHIP-1 positively regulates generation of reactive oxygen species after phagocytosis. To examine how SHIP-1 activity contributes to Fc receptor-mediated phagocytosis, we measured and compared phospholipid dynamics, membrane trafficking and the oxidative burst in macrophages from SHIP-1-deficient and wild-type mice. SHIP-1-deficient macrophages showed significantly elevated ratios of PI(3,4,5) P3 to PI(3,4)P2 on phagosomal membranes. Imaging reactive oxygen intermediate activities in phagosomes revealed decreased early NADPH oxidase activity in SHIP-1-deficient macrophages. SHIP-1-deficiency also altered later stages of phagosome maturation, as indicated by the persistent elevation of PI(3)P and the early localization of Rab5a to phagosomes. These direct measurements of individual organelles indicate that phagosomal SHIP-1 enhances the early oxidative burst through localized alteration of the membrane 3′ phosphoinositide composition. PMID:18490750

Quantity vs. quality: an exploration of the predictors of posttreatment sexual adjustment for women affected by early stage cervical and endometrial cancer.

PubMed

Juraskova, Ilona; Bonner, Carissa; Bell, Melanie L; Sharpe, Louise; Robertson, Rosalind; Butow, Phyllis

2012-11-01

Women with early stage cervical and endometrial cancer may experience complex posttreatment changes to their sexual function, but clinical practice and past research have focused more on the quantity than the perceived quality of sexual life. The aims of this prospective study were to explore the following: (i) the relative importance of quantity vs. quality of sexual life over the first year posttreatment; (ii) the psychological and sexual predictors of overall sexual function; and (iii) the relationship between sexual function and quality of life (QoL). Fifty-three cancer patients completed standardized measures at baseline, with follow-up at 6 and 12 months posttreatment. Analyses were based on prespecified linear mixed models with overall sexual function and QoL as outcomes, and quality and quantity of sexual life, anxiety, and depression as the main predictors of interest. Radiotherapy, age, and relationship satisfaction were controlled for as potential confounders. Derogatis Sexual Functioning Inventory subscales to assess quantity (Drive) and quality (Satisfaction) of sexual life, and overall sexual function (Global Sexual Satisfaction Index); Functional Assessment of Cancer Therapy--General to assess QoL; Hospital Anxiety and Depression Scale to assess psychological distress; and Relationship Satisfaction Interaction Scale to assess relationship satisfaction. The models demonstrated that: (i) overall sexual function was predicted more strongly by the perceived quality than the quantity of sexual interactions, (ii) a small change in perceived quality had a large impact on overall sexual function, and (iii) overall sexual function was a predictor of QoL. This study found that quality rather than quantity of sexual life is the best predictor of overall sexual function among women treated for early stage cervical and endometrial cancer, indicating the importance of including quality indices in posttreatment sexual assessment in clinical practice and research

The distribution of neuropeptide Y and dynorphin immunoreactivity in the brain and pituitary gland of the platyfish, Xiphophorus maculatus, from birth to sexual maturity

NASA Technical Reports Server (NTRS)

Cepriano, L. M.; Schreibman, M. P.

1993-01-01

Immunoreactive neuropeptide Y and dynorphin have been localized in the brain and pituitary gland of the platyfish, Xiphophorus maculatus, at different ages and stages of development from birth to sexual maturity. Immunoreactive neuropeptide Y was found in perikarya and tracts of the nucleus olfactoretinalis, telencephalon, ventral tegmentum and in the neurohypophysis and in the three regions of the adenohypophysis. Immunoreactive dynorphin was found in nerve tracts in the olfactory bulb and in cells of the pars intermedia and the rostral pars distalis of the pituitary gland.

‘To[o] much eating stifles the child’: fat bodies and reproduction in early modern England†

PubMed Central

Toulalan, Sarah

2013-01-01

Abstract This article examines associations between fat bodies and reproductive dysfunction that were prevalent in medical, midwifery and other literature in early modern England. In a period when fertility and successful reproduction were regarded as hugely important for social, economic and political stability such associations further contributed to negative attitudes towards fat bodies that were fuelled by connection with the vices of sloth and gluttony. Fat bodies were categorized as inherently, constitutionally, less sexual and reproductively successful. Consequently they were perceived as unhealthy and unfit for their primary purpose once they had reached sexual maturity: marriage and the production of children. PMID:25960608

"What a Girl Wants, What a Girl Needs:" Responding to Sex, Gender, and Sexuality in the Early Childhood Classroom

ERIC Educational Resources Information Center

Blaise, Mindy

2009-01-01

This paper is based on data generated from a qualitative study of gender and sexuality in a kindergarten classroom. Post-developmental perspectives of sex, gender, and sexuality are used to show how young children are constructing gender and heterosexual discourses in the early childhood classroom. Drawing from feminist post-structuralism and…

Endocrine regulation and sexual differentiation of avian copulatory sexually selected characters.

PubMed

Brennan, Patricia L R; Adkins-Regan, Elizabeth

2014-10-01

Reproductive specializations in birds have provided intriguing model systems to better understand the role of endocrine mechanisms that regulate phenotype expression and the action of sexual selection. A comparative approach can elucidate how endocrine systems associated with control of sexual differentiation, sexual maturation, and reproductive physiology and behavior have diversified. Here we compare the copulatory sexually selected traits of two members of the galloanseriform superfamily: quail and ducks. Japanese quail have a non-intromittent penis, and they have evolved a unique foam gland that is known to be involved in post-copulatory sexual selection. In contrast, ducks have maintained a large intromittent penis that has evolved via copulatory male-male competition and has been elaborated in a sexually antagonistic race due to sexual conflict with females over mating. These adaptations function in concert with sex-specific and, in part, species-specific behaviors. Although the approaches to study these traits have been different, exploring the differences in neuroendocrine regulation of sexual behavior, development and seasonality of the foam gland and the penis side by side, allow us to suggest some areas where future research would be productive to better understand the evolution of novelty in sexually selected traits. Copyright © 2014 Elsevier Ltd. All rights reserved.

Sexuality Education for Adolescents and Adults with Autism Spectrum Disorders

ERIC Educational Resources Information Center

Tullis, Christopher A.; Zangrillo, Amanda N.

2013-01-01

As people with autism spectrum disorders (ASD) mature from adolescents into adults, social deficits may become more pronounced and apparent in new areas (e.g., social functioning and sexuality). Like neurotypicals, sexuality may be directly related to quality of life for people with ASD. Current practice for addressing sexuality in the ASD…

A simple orchidometric method for the preliminary assessment of maturity status in male cynomolgus monkeys (Macaca fascicularis) used for nonclinical safety studies.

PubMed

Ku, Warren W; Pagliusi, Frank; Foley, George; Roesler, Alfred; Zimmerman, Thomas

2010-01-01

The identification and use of mature male non-human primates in nonclinical toxicology studies could be important for evaluating candidate drugs for which the profile of toxicity may differ depending on sexual maturity. This investigation sought to establish operational criteria to complement the current standard of histological evaluation for defining sexual maturity in male cynomolgus monkeys (Macaca fascicularis) used for toxicology studies, and to identify a practical non-invasive measure to select mature males for study. Retrospectively, the relationships between body weight, testicular weight and testis histology were established in control males (n=126) used in previous toxicology studies. Prospectively, testicular volumes were measured in-life by orchidometry using comparative scrotal palpation (n=23 males used for study), then compared to testicular weights measured at necropsy. Consistent with previous literature, a weak relationship was observed between body weight and testicular weight. There was, however, a very good relationship between testicular weight and histological maturation level, which was based upon microscopic examination of testes, epididymides and prostates. Orchidometric measurement of testicular volume was found to be a reasonable predictor of testicular weight and served to rapidly select sexually mature males for study, and a total testicular volume (left and right combined) of >20 ml correlated with the histological appearance of maturity. Based upon this preliminary exploratory study, the initial simple measurement of testicular volume by orchidometry may provide a non-invasive alternative approach for assessing the sexual maturity of male cynomolgus monkeys in research colonies or during toxicology studies that will require more thorough validation. Copyright 2009 Elsevier Inc. All rights reserved.

Effect of recombinant-LH and hCG in the absence of FSH on in vitro maturation (IVM) fertilization and early embryonic development of mouse germinal vesicle (GV)-stage oocytes.

PubMed

Dinopoulou, Vasiliki; Drakakis, Peter; Kefala, Stella; Kiapekou, Erasmia; Bletsa, Ritsa; Anagnostou, Elli; Kallianidis, Konstantinos; Loutradis, Dimitrios

2016-06-01

During in vitro maturation (IVM), intrinsic and extrinsic factors must co-operate properly in order to ensure cytoplasmic and nuclear maturation. We examined the possible effect of LH/hCG in the process of oocyte maturation in mice with the addition of recombinant LH (r-LH) and hCG in our IVM cultures of mouse germinal vesicle (GV)-stage oocytes. Moreover, the effects of these hormones on fertilization, early embryonic development and the expression of LH/hCG receptor were examined. Nuclear maturation of GV-stage oocytes was evaluated after culture in the presence of r-LH or hCG. Fertilization rates and embryonic development were assessed after 24h. Total RNA was isolated from oocytes of different stages of maturation and from zygotes and embryos of different stages of development in order to examine the expression of LH/hCG receptor, using RT-PCR. The in vitro nuclear maturation rate of GV-stage oocytes that received hCG was significantly higher compared to the control group. Early embryonic development was increased in the hCG and LH cultures of GV oocytes when LH was further added. The LH/hCG receptor was expressed in all stages of in vitro matured mouse oocytes and in every stage of early embryonic development. Addition of hCG in IVM cultures of mouse GV oocytes increased maturation rates significantly. LH, however, was more beneficial to early embryonic development than hCG. This suggests a promising new technique in basic science research or in clinical reproductive medicine. Copyright © 2016 Society for Biology of Reproduction & the Institute of Animal Reproduction and Food Research of Polish Academy of Sciences in Olsztyn. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

How has early testicular cancer affected your life? A study of sexual function in men attending active surveillance for stage one testicular cancer.

PubMed

Brand, Sue; Williams, Hilary; Braybrooke, Jeremy

2015-06-01

Testicular cancer is the most common cancer in young men, it is frequently diagnosed at key times in relationship formation. In early stage disease the vast majority of tumours will be cured by surgery alone with patients being offered active surveillance rather than adjuvant therapies. To date, research has not evaluated how surveillance alone impacts on sexual function. The aim of this quantitative longitudinal study was to ascertain the sexual function of men with stage one disease at 3 and 12 months post diagnosis and to compare with normative data. Additional data was collected on the information men sought regarding sexual function and media they used to access this. This study shows that men's sexual function is altered at diagnosis and improves by 3 months. At 12 months, whilst not statistically significant, sexual function improves but not to the same level as normative data comparison. Men appear to find verbal information useful at 3 months, however men appear to be seeking written and online information at 12 months. The intricacies of sexual function together with the low number of participants may have been best met with a qualitative approach. However, the information data indicates the importance of further research into the effects of early stage testicular cancer on sexual function. Therefore, further qualitative research is recommended to explore the effects of early stage testicular cancer in relation to sexual function. Copyright © 2014 Elsevier Ltd. All rights reserved.

[Perinatal clomiphene citrate treatment changes sexual orientations of male mice].

PubMed

He, Feng-Qin; Zhang, Heng-Rui

2013-10-01

Perinatal period and adolescence are critical for brain development, which is the biological basis of an individual's sexual orientation and sexual behavior. In this study, animals were divided into two groups and their sexual orientations were observed: one group experienced drug treatments during the perinatal period, and the other group was castrated at puberty. The results showed that estradiol treatment had no effect on mature male offspring's sexual orientations, but 9 days and 14 days of clomiphene citrate treatment significantly increased the chance of homosexuality and effeminized behavior. In addition, the sexual orientation of mature normal male offspring, which were castrated when they were 21 days old,was not significant different from the control animals. These findings suggest that the inhibition of perinatal estrogen activities could suppress individual male-typical responses, enhance female-typical responses and induce homosexual orientations. Moreover, the masculinizing effects of estrogen were more obvious during perinatal period than adolescence.

Is Parenting Associated with Teenagers' Early Sexual Risk-Taking, Autonomy And Relationship with Sexual Partners?

PubMed Central

Parkes, Alison; Henderson, Marion; Wight, Daniel; Nixon, Catherine

2011-01-01

CONTEXT: Extensive research has explored the relationship between parenting and teenagers’ sexual risk-taking. Whether parenting is associated with wider aspects of teenagers’ capacity to form satisfying sexual relationships is unknown. METHODS: Self-reported data were collected in 2007 from 1,854 students, whose average age was 15.5 years, in central Scotland. Multivariate analyses examined associations between parenting processes and sexual outcomes (delayed first intercourse, condom use and several measures reflecting the context or anticipated context of first sex). RESULTS: Parental supportiveness was positively associated with all outcomes (betas, 0.1–0.4), and parental values restricting intercourse were positively associated with all outcomes except condom use (0.1–0.5). Parental monitoring was associated only with delayed intercourse (0.2) and condom use (0.2); parental rules about TV content were associated with delayed intercourse (0.7) and expecting sex in a relationship, rather than casually (0.8). Frequency of parental communication about sex and parental values endorsing contraceptive use were negatively associated with teenagers’ delayed intercourse (–0.5 and –0.3, respectively), and parents’ contraceptive values were negatively associated with teenagers’ expecting sex in a relationship (–0.5). Associations were partly mediated by teenagers’ attitudes, including value placed on having sex in a relationship. CONCLUSIONS: Parents may develop teenagers’ capacity for positive and safe early sex by promoting skills and values that build autonomy and encourage sex only within a relationship. Interventions should promote supportive parenting and transmission of values, avoid mixed messages about abstinence and contraception, and acknowledge that teenagers may learn more indirectly than directly from parents about sex. PMID:21388503

Correspondence between Gonadal Steroid Hormone Concentrations and Secondary Sexual Characteristics Assessed by Clinicians, Adolescents, and Parents

ERIC Educational Resources Information Center

Huang, Bin; Hillman, Jennifer; Biro, Frank M.; Ding, Lili; Dorn, Lorah D.; Susman, Elizabeth J.

2012-01-01

Adolescent sexual maturation is staged using Tanner criteria assessed by clinicians, parents, or adolescents. The physiology of sexual maturation is driven by gonadal hormones. We investigate Tanner stage progression as a function of increasing gonadal hormone concentration and compare performances of different raters. Fifty-six boys (mean age,…

Parental Monitoring during Early Adolescence Deters Adolescent Sexual Initiation: Discrete-Time Survival Mixture Analysis

ERIC Educational Resources Information Center

Huang, David Y. C.; Murphy, Debra A.; Hser, Yih-Ing

2011-01-01

We used discrete-time survival mixture modeling to examine 5,305 adolescents from the 1997 National Longitudinal Survey of Youth regarding the impact of parental monitoring during early adolescence (ages 14-16) on initiation of sexual intercourse and problem behavior engagement (ages 14-23). Four distinctive parental-monitoring groups were…

Early Adolescent Sexual Initiation and Physical/Psychological Symptoms: A Comparative Analysis of Five Nations

ERIC Educational Resources Information Center

Madkour, Aubrey Spriggs; Farhat, Tilda; Halpern, Carolyn Tucker; Godeau, Emmanuelle; Nic Gabhainn, Saoirse

2010-01-01

Although most people in developed countries experience sexual initiation during adolescence, little is known about inter-country variability in the psychosocial correlates of early initiation. Population-based samples of 15-year-olds (n = 6,111, 52% female) who participated in the Health Behaviors in School-Aged Children Study (Finland, Scotland,…

Sexual functioning among early post-treatment breast cancer survivors.

PubMed

Avis, Nancy E; Johnson, Aimee; Canzona, Mollie Rose; Levine, Beverly J

2018-02-17

This study aims (1) to estimate percentages of partnered women who are sexually active over the first 2 years post-breast cancer diagnosis; (2) to identify factors related to sexual inactivity; and (3) to evaluate separately, among both sexually active and inactive survivors, the relation between sexual problems and treatment-related variables, symptoms, and psychosocial factors. Longitudinal observational study of breast cancer survivors recruited within 8 months of cancer diagnosis and followed for 18 months. The main outcome measures were (1) being sexually active/inactive in the past month and (2) sexual problems assessed with the four-item sexual problem domain of the Quality of Life in Adult Cancer Survivors (QLACS) scale. At baseline, 52.4% of women reported being sexually active in the past month. This percentage increased to 60.7% 18 months later. In multivariable repeated-measures analyses, age, past chemotherapy, depressive symptoms, and lower perceived attractiveness were related to inactivity. Sexually inactive women reported more problems on the QLACS than sexually active women. In stratified multivariable analyses, depressive symptoms were related to greater sexual problems for both sexually active and inactive women, as was vaginal dryness. Among the sexually active women, younger age at diagnosis, less illness intrusiveness, and lower perceived attractiveness were related to more problems. Research has shown that sexual functioning/sexual health are key aspects of quality of life for many cancer survivors, and are often not addressed by health care providers. Future studies should examine how such topics are handled by clinicians in their interactions with survivors.

The Medical Analysis of Child Sexual Abuse Images

ERIC Educational Resources Information Center

Cooper, Sharon W.

2011-01-01

Analysis of child sexual abuse images, commonly referred to as pornography, requires a familiarity with the sexual maturation rating of children and an understanding of growth and development parameters. This article explains barriers that exist in working in this area of child abuse, the differences between subjective and objective analyses,…

The Impact of Body Image and Afrocentric Appearance on Sexual Refusal Self-Efficacy in Early Adolescent African American Girls

ERIC Educational Resources Information Center

Plybon, Laura E.; Holmer, Heidi; Hunter, Alexis; Sheffield, Charity; Stephens, Christopher; Cavolo, Lucas

2009-01-01

Research examining the association between body image and sexual risk-taking has been mostly limited to clinical and/or White female samples. It is unclear whether body image plays a role in sexual risk-taking among African American early adolescent females. Moreover, research has neglected to consider body image within a cultural and ethnic…

The effects of differential prenatal and postnatal social enviroments on sexual maturation of young prairie deermice (Peromyscus maniculatus bairdii).

PubMed

Thomas, D; Terman, C R

1975-05-01

We compared the influence of different social enviroments on sexual maturation of young prairie deermice. Between 12 and 48 hr after parturition, one-half of a litter from a population was exchanged with one-half of a litter from a bisexual pair. In each situation the remaining half-litter served as controls for the exchange procedure. The testes and vesicular weights of population-reared males were significantly larger than those of males reared by bisexual pairs, irrespective of prenatal enviroment. Generally, population-reared females also had larger reproductive organs than those reared by bisexual pairs, although these differences were not statistically significant. There were no significant differences in the adrenal weights of males or females, but females reared by bisexual pairs had larger absolute and relative adrenals than females reared in populations.

Early-life sexual segregation: ontogeny of isotopic niche differentiation in the Antarctic fur seal

NASA Astrophysics Data System (ADS)

Kernaléguen, L.; Arnould, J. P. Y.; Guinet, C.; Cazelles, B.; Richard, P.; Cherel, Y.

2016-09-01

Investigating the ontogeny of niche differentiation enables to determine at which life-stages sexual segregation arises, providing insights into the main factors driving resource partitioning. We investigated the ontogeny of foraging ecology in Antarctic fur seals (Arctocephalus gazella), a highly dimorphic species with contrasting breeding strategies between sexes. Sequential δ13C and δ15N values of whiskers provided a longitudinal proxy of the foraging niche throughout the whole life of seals, from weaning, when size dimorphism is minimal to the age of 5. Females exhibited an early-life ontogenetic shift, from a total segregation during their first year at-sea, to a similar isotopic niche as breeding females as early as age 2. In contrast, males showed a progressive change in isotopic niche throughout their development such that 5-year-old males did not share the same niche as territorial bulls. Interestingly, males and females segregated straight after weaning with males appearing to feed in more southerly habitats than females. This spatial segregation was of similar amplitude as observed in breeding adults and was maintained throughout development. Such early-life niche differentiation is an unusual pattern and indicates size dimorphism and breeding constraints do not directly drive sexual segregation contrary to what has been assumed in otariid seals.

Adolescent Sexuality: Pregnancy, Sexually Transmitted Diseases, and Prevention.

ERIC Educational Resources Information Center

Santelli, John S.; And Others

1992-01-01

Special edition discusses adolescent sexuality, focusing on pregnancy, sexually transmitted diseases, and prevention. The articles focus on demographics, risk factors, school-based risk reduction programs, contraception, early intervention, options, school-based prenatal and postpartum care programs, teenage parenting, abortion, HIV and AIDS,…

Ontogenetic shape changes and sexual dimorphism in Aegla marginata Bond-Buckup and Buckup, 1994.

PubMed

Adam, Carolina L; Marochi, Murilo Z; Masunari, Setuko

2018-05-14

A study on relative growth, sexual dimorphism and ontogenetic trajectory was carried out in a population of the aeglidAegla marginata coming from Barrinha River, Iguape River Basin, Tunas do Paraná, Paraná State, Brazil. The size the of morphological sexual maturity was estimated for males and females. The analysis of sexual dimorphism and ontogenetic trajectory were performed using geometric morphometric technique. Males reach maturity with 10.58 mm of carapace length (CL) and females with 10.38 mm CL. Sexual size dimorphism was only visible among adults, with males reaching larger sizes. This is probably related to the reproductive strategy of males. However, sexual shape dimorphism was found for both juveniles and adults: the posterior region of the carapace was wider in females. As the contrast of this feature was stronger in adults, it can be considered that large abdomen is advantageous for egg incubation. The allometric trajectories of juveniles presented similar directions, becoming divergent during the adult phase. The shape variation inA. marginataoccurred gradually throughout its development, with no abrupt transformation upon reaching sexual maturity. The reproductive adaptation is the main reason for the morphological variation within populations ofA. marginata.

Trauma and Sexuality: The Effects of Childhood Sexual, Physical, and Emotional Abuse on Sexual Identity and Behavior.

ERIC Educational Resources Information Center

Chu, James A., Ed.; Bowman, Elizabeth S., Ed.

This book examines the effects of childhood trauma--including sexual abuse--on sexual orientation and behavior. It is directed at helping counselors expand their sensitivity and expertise in a critically important way: by providing a nonjudgmental look at the profound effects of long-standing early abuse on the sexual identities, orientation,…

Including a Client Sexual Health Pathway in a National Youth Mental Health Early Intervention Service--Project Rationale and Implementation Strategy

ERIC Educational Resources Information Center

Edwards, C. A.; Britton, M. L.; Jenkins, L.; Rickwood, D. J.; Gillham, K. E.

2014-01-01

Young people have higher rates of sexually transmissible infections (STIs) than the general population. Research has shown that there is a clear link between emotional distress, depression, substance abuse and sexual risk taking behaviours in young people. "headspace" is a youth mental health early intervention service operating in more…

Effects of feeding regimes and early maturation on migratory behaviour of landlocked hatchery-reared Atlantic salmon Salmo salar smolts.

PubMed

Norrgård, J R; Bergman, E; Schmitz, M; Greenberg, L A

2014-10-01

The migratory behaviour of hatchery-reared landlocked Atlantic salmon Salmo salar raised under three different feeding regimes was monitored through the lower part of the River Klarälven, Sweden. The smolts were implanted with acoustic transmitters and released into the River Klarälven, 25 km upstream of the outlet in Lake Vänern. Early mature males, which had matured the previous autumn, were also tagged and released. To monitor migration of the fish, acoustic receivers were deployed along the migratory route. The proportion of S. salar that reached Lake Vänern was significantly greater for fish fed fat-reduced feed than for fish given rations with higher fat content, regardless of ration size. Fish from the early mature male group remained in the river to a greater extent than fish from the three feeding regimes. Smolt status (degree of silvering), as visually assessed, did not differ among the feeding regime groups, and moreover, fully-silvered fish, regardless of feeding regime, migrated faster and had a greater migration success than fish with less developed smolt characteristics. Also, successful migrants had a lower condition factor than unsuccessful ones. These results indicate that the migration success of hatchery-reared S. smolts released to the wild can be enhanced by relatively simple changes in feeding regimes and by matching stocking time with smolt development. © 2014 The Fisheries Society of the British Isles.

An exploratory study of parent-child communication about sex and the sexual attitudes of early, middle, and late adolescents.

PubMed

Fisher, T D

1986-12-01

In an attempt to examine the relationship between parent-child communication about sex and parent-adolescent attitudes about sex, 12- to 20-year-olds (N = 141) and their parents completed sexual communication and attitude questionnaires. The correlation between parents' and children's attitudes were high for all the early adolescents and low for all the middle adolescents. Only among the late adolescents was there a significant difference in the correlations between the sexual attitudes of parents and their children as a function of family communication level, with the attitudes of adolescents and parents in the high communication group being highly correlated and the attitudes of adolescents and parents in the low communication group not being significantly correlated. Middle adolescents had significantly more permissive sexual attitudes than early and late adolescents. Gender variables were also studied, but conclusions were limited due to the small number of participating fathers. All findings must be tempered with the recognition of the possible sampling bias introduced by the use of a convenience sample. It is suggested that the more responsible sexuality seen in adolescents who can talk to their parents about sex may be a function of the similarity in sexual attitudes between these late adolescents and their parents.

The socio-political context of migration and reproductive health disparities: The case of early sexual initiation among Mexican-origin immigrant young women

PubMed Central

Coleman-Minahan, Kate

2017-01-01

Prior research often explains the lower risk of early sexual initiation among foreign-born Mexican-origin young women by a patriarchal and sexually conservative “traditional Latino culture.” This definition overlooks structural factors such as exploitation of migrant workers, and conflates gender inequality and sexual expectations. I use an intersectional framework and the theory of gender and power to explore how gender inequality and sexual expectations are both influenced by structural factors and affect reproductive health outcomes. I integrate data from qualitative interviews with 21 first and second generation Mexican-origin women in 2013–2014 with data from discrete time hazard models with 798 Mexican-origin young women in the National Longitudinal Study of Adolescent to Adult Health. Qualitative results demonstrate that gender inequality and sexual expectations in Mexican-origin immigrant households are associated with structural factors. Gender inequality occurs more often in households with family instability, greater poverty, and among parents who migrated independently. Qualitative data also demonstrate that parental gendered expectations are sometimes at odds to what parents are actually doing in the household. Finally, contrary to assumptions that a patriarchal “traditional Latino culture” protects against early sexual initiation, qualitative and multivariate quantitative data suggest that household gender inequality increases risk of early sexual initiation. These findings challenge the utility of a culturalist approach that views culture as determining behavior to explain health disparities among immigrants and demonstrate the need to incorporate an intersectional framework that includes structural factors. This approach may reduce stereotypes and identify meaningful interventions to reduce reproductive health disparities. PMID:28324794

Linking Childhood Maltreatment with Girls’ Internalizing Symptoms: Early Puberty as a Tipping Point

PubMed Central

Mendle, Jane; Leve, Leslie D.; Van Ryzin, Mark; Natsuaki, Misaki N.

2013-01-01

Early pubertal timing in girls is one of the most frequently replicated antecedents of adolescent emotional distress. Yet understanding the impact of pubertal timing in psychosocial development has presented something of a conundrum for developmentalists, as earlier physical maturation may often be preceded by a range of early adversities and life stressors. The present paper disentangles these associations by investigating childhood maltreatment, adolescent internalizing symptoms, and perceived pubertal timing in girls who were residing in foster care at study entry (N = 100, M = 11.54 years old at Time 1). Girls were assessed at two time points two years apart. There were no significant direct effects of maltreatment on internalizing symptoms; rather, childhood sexual abuse predicted earlier perceived pubertal development at study onset which, in turn, was associated with higher levels of internalizing symptomatology. These higher levels of internalizing symptoms persisted over the two years of the study. This distinctive role for early pubertal timing – even within a sample subject to stressors and risks which far exceed the developmental norm – confirms the unique salience of pubertal timing in emotional adjustment, and suggests that the heightened sexual circumstances of puberty may be especially disturbing for girls whose lives have already been traumatically disrupted by inappropriate and unwanted sexual experiences. PMID:25419091

Pomerelle Russet: An early maturing potato variety with high yield of U.S. No.1 tubers suitable for fresh market and early processing and resistance to Potato mop top virus and corky ringspot

USDA-ARS?s Scientific Manuscript database

Pomerelle Russet is an early maturing fresh potato variety, which produces moderately high early-season yields of oblong-long tubers with brown-russet skin. It is notable for its very attractive, smooth tubers and resistances to internal and external defects with a high percentage of U.S. No. 1 tube...

Quantitative genetics of plumage color: lifetime effects of early nest environment on a colorful sexual signal

PubMed Central

Hubbard, Joanna K; Jenkins, Brittany R; Safran, Rebecca J

2015-01-01

Phenotypic differences among individuals are often linked to differential survival and mating success. Quantifying the relative influence of genetic and environmental variation on phenotype allows evolutionary biologists to make predictions about the potential for a given trait to respond to selection and various aspects of environmental variation. In particular, the environment individuals experience during early development can have lasting effects on phenotype later in life. Here, we used a natural full-sib/half-sib design as well as within-individual longitudinal analyses to examine genetic and various environmental influences on plumage color. We find that variation in melanin-based plumage color – a trait known to influence mating success in adult North American barn swallows (Hirundo rustica erythrogaster) – is influenced by both genetics and aspects of the developmental environment, including variation due to the maternal phenotype and the nest environment. Within individuals, nestling color is predictive of adult color. Accordingly, these early environmental influences are relevant to the sexually selected plumage color variation in adults. Early environmental conditions appear to have important lifelong implications for individual reproductive performance through sexual signal development in barn swallows. Our results indicate that feather color variation conveys information about developmental conditions and maternal care alleles to potential mates in North American barn swallows. Melanin-based colors are used for sexual signaling in many organisms, and our study suggests that these signals may be more sensitive to environmental variation than previously thought. PMID:26380676

Evaluating the Need for Sex Education in Developing Countries: Sexual Behaviour, Knowledge of Preventing Sexually Transmitted Infections/HIV and Unplanned Pregnancy

ERIC Educational Resources Information Center

Singh, Susheela; Bankole, Akinrinola; Woog, Vanessa

2005-01-01

Young people's need for sex education is evidenced by their typically early initiation of sexual activity, the often involuntary context within which they have sexual intercourse, high-risk sexual behaviours and the inadequate levels of knowledge of means of protecting their sexual health. The earliness of initiation of sexual intercourse has…

"Where Do Babies Come from?" Barriers to Early Sexuality Communication between Parents and Young Children

ERIC Educational Resources Information Center

Stone, Nicole; Ingham, Roger; Gibbins, Katie

2013-01-01

"Where do babies come from?" "Why do boys have willies?" "What does gay mean?" Probably all parents have faced such "innocent" questions from young children, and many have found them challenging to answer. Access to sexuality education at an early age is frequently considered controversial; however, there…

Relative Skeletal Maturation and Population Ancestry in Nonobese Children and Adolescents.

PubMed

McCormack, Shana E; Chesi, Alessandra; Mitchell, Jonathan A; Roy, Sani M; Cousminer, Diana L; Kalkwarf, Heidi J; Lappe, Joan M; Gilsanz, Vicente; Oberfield, Sharon E; Shepherd, John A; Mahboubi, Soroosh; Winer, Karen K; Kelly, Andrea; Grant, Struan Fa; Zemel, Babette S

2017-01-01

More rapid skeletal maturation in African-American (AA) children is recognized and generally attributed to an increased prevalence of obesity. The objective of the present study was to evaluate the effects of population ancestry on relative skeletal maturation in healthy, non-obese children and adolescents, accounting for body composition and sexual maturation. To do this, we leveraged a multiethnic, mixed-longitudinal study with annual assessments for up to 7 years (The Bone Mineral Density in Childhood Study and its ancillary cohort) conducted at five US clinical centers. Participants included 1592 children, skeletally immature (45% females, 19% AA) who were aged 5 to 17 years at study entry. The primary outcome measure was relative skeletal maturation as assessed by hand-wrist radiograph. Additional covariates measured included anthropometrics, body composition by dual-energy X-ray absorptiometry (DXA), and Tanner stage of sexual maturation. Using mixed effects longitudinal models, without covariates, advancement in relative skeletal maturation was noted in self-reported AA girls (∼0.33 years, p < 0.001) and boys (∼0.43 years, p < 0.001). Boys and girls of all ancestry groups showed independent positive associations of height, lean mass, fat mass, and puberty with relative skeletal maturation. The effect of ancestry was attenuated but persistent after accounting for covariates: for girls, 0.19 years (ancestry by self-report, p = 0.02) or 0.29 years (ancestry by admixture, p = 0.004); and for boys, 0.20 years (ancestry by self-report, p = 0.004), or 0.29 years (ancestry by admixture, p = 0.004). In summary, we conclude that advancement in relative skeletal maturation was associated with AA ancestry in healthy, non-obese children, independent of growth, body composition, and puberty. Further research into the mechanisms underlying this observation may provide insights into the regulation of skeletal maturation. © 2016 American Society

Clinical factors are not the best predictors of quality of sexual life and sexual functioning in women with early stage breast cancer.

PubMed

Den Oudsten, Brenda L; Van Heck, Guus L; Van der Steeg, Alida F W; Roukema, Jan A; De Vries, Jolanda

2010-06-01

Few studies have prospectively assessed the impact of breast cancer (BC) on women's sexual lives. Therefore, this study examines the determinants of quality of sexual life (QOSL), sexual functioning (SF), and sexual enjoyment (SE) at 6 and 12 months after surgical treatment. All participants completed a measure of QOSL (The World Health Organization Quality of Life assessment instrument-100 (WHOQOL-100)-facet Sexual Activity) before diagnosis (Time-1), and 1 (Time-2), 3 (Time-3), 6 (Time-4) and 12 months (Time-5) after surgical treatment. At Time-1, women also completed questionnaires on personality (The State Trait Anxiety Inventory-trait, NEO-FFI), body image and self-esteem (WHOQOL-100), depressive symptoms (Center for Epidemiological Studies-Depression Scale), and fatigue (Fatigue Assessment Scale). Furthermore, SF and SE (The European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Breast Cancer module) were measured from Time-2 onwards. At baseline, the analysis included 223 women with early stage BC. Clinical factors did not predict QOSL, SF or SE. In the final analyses, trait anxiety predicted QOSL and SF at Time-4 (p's<0.01). At Time-5, agreeableness predicted QOSL and SE (p's<0.05). Having a partner and age predicted SF, while SE was predicted by educational level (Time-4). In addition, fatigue predicted SE at Time-4 (p<0.05). In general, QOSL diminished across time, while SF improved. However, women with a mastectomy did not differ from women with breast conserving therapy. Mainly personality and psychological factors affect patients' sexuality after surgical treatment. Clinical factors did not predict QOSL, SF or SE. More knowledge in this field will help professionals to identify women who are at risk of experiencing sexual problems and consequently will contribute to provide adequate support. (c) 2009 John Wiley & Sons, Ltd.

Linking Self-Regulation and Risk Proneness to Risky Sexual Behavior: Pathways through Peer Pressure and Early Substance Use

ERIC Educational Resources Information Center

Crockett, Lisa J.; Raffaelli, Marcela; Shen, Yuh-Ling

2006-01-01

The linkages between self-regulation in childhood, risk proneness in early adolescence, and risky sexual behavior in mid-adolescence were examined in a cohort of children (N=518) from the National Longitudinal Survey of Youth. The possible mediating role of two early adolescent variables (substance use and negative peer pressure) was also…

Basic Instinct Undressed: Early Spatiotemporal Processing for Primary Sexual Characteristics

PubMed Central

Legrand, Lore B.; Del Zotto, Marzia; Tyrand, Rémi; Pegna, Alan J.

2013-01-01

This study investigates the spatiotemporal dynamics associated with conscious and non-conscious processing of naked and dressed human bodies. To this effect, stimuli of naked men and women with visible primary sexual characteristics, as well as dressed bodies, were presented to 20 heterosexual male and female participants while acquiring high resolution EEG data. The stimuli were either consciously detectable (supraliminal presentations) or were rendered non-conscious through backward masking (subliminal presentations). The N1 event-related potential component was significantly enhanced in participants when they viewed naked compared to dressed bodies under supraliminal viewing conditions. More importantly, naked bodies of the opposite sex produced a significantly greater N1 component compared to dressed bodies during subliminal presentations, when participants were not aware of the stimulus presented. A source localization algorithm computed on the N1 showed that the response for naked bodies in the supraliminal viewing condition was stronger in body processing areas, primary visual areas and additional structures related to emotion processing. By contrast, in the subliminal viewing condition, only visual and body processing areas were found to be activated. These results suggest that naked bodies and primary sexual characteristics are processed early in time (i.e., <200 ms) and activate key brain structures even when they are not consciously detected. It appears that, similarly to what has been reported for emotional faces, sexual features benefit from automatic and rapid processing, most likely due to their high relevance for the individual and their importance for the species in terms of reproductive success. PMID:23894532

Basic instinct undressed: early spatiotemporal processing for primary sexual characteristics.

PubMed

Legrand, Lore B; Del Zotto, Marzia; Tyrand, Rémi; Pegna, Alan J

2013-01-01

This study investigates the spatiotemporal dynamics associated with conscious and non-conscious processing of naked and dressed human bodies. To this effect, stimuli of naked men and women with visible primary sexual characteristics, as well as dressed bodies, were presented to 20 heterosexual male and female participants while acquiring high resolution EEG data. The stimuli were either consciously detectable (supraliminal presentations) or were rendered non-conscious through backward masking (subliminal presentations). The N1 event-related potential component was significantly enhanced in participants when they viewed naked compared to dressed bodies under supraliminal viewing conditions. More importantly, naked bodies of the opposite sex produced a significantly greater N1 component compared to dressed bodies during subliminal presentations, when participants were not aware of the stimulus presented. A source localization algorithm computed on the N1 showed that the response for naked bodies in the supraliminal viewing condition was stronger in body processing areas, primary visual areas and additional structures related to emotion processing. By contrast, in the subliminal viewing condition, only visual and body processing areas were found to be activated. These results suggest that naked bodies and primary sexual characteristics are processed early in time (i.e., <200 ms) and activate key brain structures even when they are not consciously detected. It appears that, similarly to what has been reported for emotional faces, sexual features benefit from automatic and rapid processing, most likely due to their high relevance for the individual and their importance for the species in terms of reproductive success.

Identification and action of juvenile hormone III from sexually mature alate females of the red imported fire ant, Solenopsis invicta.

PubMed

Burns, S N.; Teal, P E.A.; Vander Meer, R K.; Nation, J L.; Vogt, J T.

2002-03-01

Analysis of extracts of hemolymph obtained from sexually mature alate females of Solenopsis invicta from monogyne colonies resulted in identification of juvenile hormone III (JH III). The average amount of JH III was 0.32+/-0.04 pmol/&mgr;molof hemolymph. Topical application of 0.038 pmol of JH III was sufficient to stimulate alates to shed their wings in the presence of the queen. The time in which alates were induced to dealate decreased linearly with increasing concentrations of JH III from 0.038 to 3.8 pmol. However, higher JH III concentrations deviated from linearity and did not reach dealation times comparable with those that occur after mating flights. Thus, it appears that the mechanism of dealation that occurs when female alates are out of the influence of their queen is different from the one associated with mating flights. Application of 0.42 &mgr;mol of precocene II inhibited dealation of alates in queenless colonies. However, this inhibition was reversed after applying 38 pmol JH III to precocene-treated alates. The sizes of corpora allata (CA) from sexuals treated with JH III did not differ from those of controls. However, the sizes of CA were reduced in alates treated with precocene II. The results indicated that JH was important to dealation.

Mental Health Issues Related to Sexual Orientation in a High School Setting

ERIC Educational Resources Information Center

Williams, Susan G.

2017-01-01

High school students are maturing physically, psychosocially, and sexually. Some may be unsure of their sexual orientation. The purpose of the study was to determine whether students who self-identified as homosexual-lesbian/gay, bisexual (LGB), and unsure of sexual orientation had more stressful life events (SLEs), perceived stress, bullying…

Sexual Anxiety and Eroticism Predict the Development of Sexual Problems in Youth With a History of Sexual Abuse

PubMed Central

Simon, Valerie A.; Feiring, Candice

2017-01-01

Youth with confirmed histories of sexual abuse (N = 118) were followed longitudinally to examine associations between their initial sexual reactions to abuse and subsequent sexual functioning. Participants were interviewed at abuse discovery (ages 8 through 15) and again 1 and 6 years later. Eroticism and sexual anxiety emerged as distinct indices of abuse-specific sexual reactions and predicted subsequent sexual functioning. Eroticism was associated with indicators of heightened sexuality, including more sexual risk behavior and views of sexual intimacy focused on partners’ needs. Sexual anxiety was associated with indicators of diminished sexuality, including few sexual partners and avoidant views of sexual intimacy. Age at abuse discovery moderated some associations, suggesting that the timing of abuse-specific reactions affects trajectories of sexual development. Findings point to the need for a developmental approach to understanding how abuse-specific sexual reactions disrupt sexual development and the need for early interventions promoting healthy sexual development. PMID:18408212

Identification and characterization of adolescents' sexual boundaries.

PubMed

Wolf, Hilary T; Morrell, Holly E R; Halpern-Felsher, Bonnie L

2013-07-01

Adolescents' decisions to have sex may be based on a priori boundaries placed on sex. This study addresses: (1) to what extent adolescents set vaginal sexual boundaries; (2) the types of sexual boundaries most and least likely to be endorsed; and (3) to what extent sexual boundaries vary by sex, race/ethnicity, and sexual experience. A cross-sectional study of 518 students attending 10th grade. Survey measures queried about demographics, ever having sex, and existence of sexual boundaries (e.g., being in love, having an attractive partner) that must be in place before having vaginal sex. The most frequently endorsed boundaries were maturity, commitment, trust, love, and marriage. These boundaries were more frequently endorsed than having a safer-sex method. Compared with females, males were more likely to choose boundaries based on partner attractiveness (p < .001) and avoiding trouble (p < .04). Compared with Asians and Pacific Islanders, whites were more likely to endorse wanting to be a certain age to have sex (p < .01 and p < .05, respectively); Asians and Pacific Islanders were more likely to choose sexual boundaries based on marriage (p's < .05). Adolescents who were sexually experienced were more likely than inexperienced adolescents to endorse boundaries related to relationship characteristics and partner attractiveness (OR = 2.5), and less likely to endorse boundaries related to feeling mature (OR = .34) and waiting until marriage (OR = .34). Identifying adolescents' sexual boundaries should help healthcare professionals better understand under what circumstances adolescents are more or less likely to have sex; and this information should ultimately inform the development of new interventions. Copyright © 2013 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Changes in Parent-Child Relationship Quality across Early Adolescence: Implications for Engagement in Sexual Behavior

ERIC Educational Resources Information Center

McElwain, Alyssa D.; Bub, Kristen L.

2018-01-01

The present study investigated how changes in specific dimensions of the parent-adolescent relationship predict adolescent engagement in sexual intercourse and oral sex. Longitudinal data from 1,364 participants in the National Institute of Child Health and Human Development (NICHD) Study of Early Child Care and Youth Development were gathered at…

Does Father Absence Place Daughters at Special Risk for Early Sexual Activity and Teenage Pregnancy?

ERIC Educational Resources Information Center

Ellis, Bruce J.; Bates, John E.; Dodge, Kenneth A.; Fergusson, David M.; Horwood, L. John; Pettit, Gregory S.; Woodward, Lianne

2003-01-01

Longitudinal studies in two countries investigated impact of father absence on girls' early sexual activity (ESA) and teenage pregnancy. Findings indicated that greater exposure to father absence strongly related to elevated ESA and adolescent pregnancy risk. Elevated risk was not explained (U.S. sample) or only partly explained (New Zealand…

Involving the Hard to Reach: Developing and Evaluating a Sexual Health Programme for Early School Leavers in Hong Kong

ERIC Educational Resources Information Center

Wong, William C. W.; Holroyd, Eleanor A.; Lee, Albert; Wong, Jonathan C. P.; Leung, Phil W. S.

2011-01-01

Early school leavers cannot access school-based sex education programmes, increasing their vulnerability to sexual health issues. This study evaluated a culturally-sensitive and target-orientated sex education programme involving this group. Early school leavers were recruited from two branches of the Chinese Young Men's Christian Association in…

Urban Early Adolescent Narratives on Sexuality: Accidental and Intentional Influences of Family, Peers, and the Media.

PubMed

Charmaraman, Linda; McKamey, Corinne

2011-01-01

In this paper, we examine the ways that early adolescents talked, interacted, and made references to events in their individual and collective lives during photography-based focus groups about sexuality and relationships. Twenty-three participants (10 boys and 13 girls) were recruited from three urban schools participating in a comprehensive sex education impact evaluation in the Northeast. We analyzed conversational narratives that were elicited in a group process while sharing photos of important people, contexts, and situations, showcasing participants' exploration of sexuality and relationships. Our analysis revealed four main themes: (a) direct and indirect family communication about sexuality, (b) accidental and intentional Internet usage, (c) shared and contested peer knowledge, and (d) school as a direct and indirect learning context. Implications and future directions for practice, research, and policy are explored.

Urban Early Adolescent Narratives on Sexuality: Accidental and Intentional Influences of Family, Peers, and the Media

PubMed Central

McKamey, Corinne

2012-01-01

In this paper, we examine the ways that early adolescents talked, interacted, and made references to events in their individual and collective lives during photography-based focus groups about sexuality and relationships. Twenty-three participants (10 boys and 13 girls) were recruited from three urban schools participating in a comprehensive sex education impact evaluation in the Northeast. We analyzed conversational narratives that were elicited in a group process while sharing photos of important people, contexts, and situations, showcasing participants’ exploration of sexuality and relationships. Our analysis revealed four main themes: (a) direct and indirect family communication about sexuality, (b) accidental and intentional Internet usage, (c) shared and contested peer knowledge, and (d) school as a direct and indirect learning context. Implications and future directions for practice, research, and policy are explored. PMID:22983141

A longitudinal examination of the influence of maturation on physical self-perceptions and the relationship with physical activity in early adolescent girls.

PubMed

Knowles, Ann-Marie; Niven, Ailsa G; Fawkner, Samantha G; Henretty, Joan M

2009-06-01

This longitudinal study investigated the influence of maturation on physical self-perceptions and the relationship with physical activity in early adolescent girls (N=150; mean age=12.79+/-0.31). Physical characteristics were measured and participants completed the Physical Activity Questionnaire for Children, the Children and Youth Physical Self-Perception Profile and the Pubertal Development Scale on two occasions 12 months apart. The results demonstrated a decrease in overall physical activity levels over 12 months which was not influenced by maturational status or physical characteristics. Additional analysis indicated that physical self-perceptions partially accounted for the explained variance in physical activity change, with physical condition being an important individual predictor of physical activity. Further analysis indicated that body mass was an important individual predictor of changes in perceptions of body attractiveness and physical self-worth. At this age maturation has a limited influence on the physical activity behaviours of early adolescent girls and although the variance in physical activity was partly accounted for by physical self-perceptions, this was a relatively small contribution and other factors related to this drop in physical activity need to be considered longitudinally.

The Relationship between Childhood Sexual Abuse and Sexual Dysfunction in Jamaican Adults

ERIC Educational Resources Information Center

Swaby, Antoneal N.; Morgan, Kai A. D.

2009-01-01

This study examined the associations between early traumatic sexualization and later sexual dysfunction in a sample of 100 Jamaican adults while identifying the linkages between age, frequency of abuse, and gender on sexual functioning. Participants were selected via purposive and convenience sampling and divided equally into comparison and…

Loneliness and Sexual Dysfunctions.

ERIC Educational Resources Information Center

Mijuskovic, Ben

1987-01-01

Argues that sexual dysfunctions result from early childhood experiences which were originally nonsexual in nature. Contends that psychological difficulties centered around problems of loneliness tend to generate certain sexual dysfunctions. Extends and explores suggestion that genesis of sexual conflicts is in nonsexual infant separation anxiety…

Genital tract lesions in sexually mature Göttingen minipigs during the initial stages of experimental vaginal infection with Chlamydia trachomatis serovar D.

PubMed

Erneholm, Karin; Lorenzen, Emma; Bøje, Sarah; Olsen, Anja Weinreich; Andersen, Peter; Cassidy, Joseph P; Follmann, Frank; Jensen, Henrik E; Agerholm, Jørgen S

2016-09-10

Chlamydia is one of the most common sexually transmitted diseases in humans worldwide, causing chronic lesions in the reproductive tract. Due to its often asymptomatic course, there is limited knowledge about the initial changes in the genital tract following infection. This study employs a novel sexually mature minipig model to investigate the initial histopathological changes following vaginal infection with Chlamydia trachomatis serovar D. A vaginal inoculation resulted in an infection primarily affecting the lower genital tract. The histopathological changes were characterized by a subepithelial inflammation consisting of neutrophils and mononuclear cells, followed by an increase in the number of plasma cells within the sub-epithelial stroma of the vagina. Detection of Chlamydia was associated with expression of cyclooxygenase-2 and interleukin-8 by superficial epithelial cells. The infection was self-limiting, with a duration of 7 days. Neutrophils, plasma cells and IL-8 have been linked with Chlamydia genital infection of unknown duration in human patients. In this study, we observe a similar pattern of local immune response/inflammation following experimental inoculation suggesting this porcine model shows promise as a model for translational chlamydia research.

Sexual content in video games: an analysis of the Entertainment Software Rating Board classification from 1994 to 2013.

PubMed

Vidaña-Pérez, Dèsirée; Braverman-Bronstein, Ariela; Basto-Abreu, Ana; Barrientos-Gutierrez, Inti; Hilscher, Rainer; Barrientos-Gutierrez, Tonatiuh

2018-01-11

Background: Video games are widely used by children and adolescents and have become a significant source of exposure to sexual content. Despite evidence of the important role of media in the development of sexual attitudes and behaviours, little attention has been paid to monitor sexual content in video games. Methods: Data was obtained about sexual content and rating for 23722 video games from 1994 to 2013 from the Entertainment Software Rating Board database; release dates and information on the top 100 selling video games was also obtained. A yearly prevalence of sexual content according to rating categories was calculated. Trends and comparisons were estimated using Joinpoint regression. Results: Sexual content was present in 13% of the video games. Games rated 'Mature' had the highest prevalence of sexual content (34.5%) followed by 'Teen' (30.7%) and 'E10+' (21.3%). Over time, sexual content decreased in the 'Everyone' category, 'E10+' maintained a low prevalence and 'Teen' and 'Mature' showed a marked increase. Both top and non-top video games showed constant increases, with top selling video games having 10.1% more sexual content across the period of study. Conclusion: Over the last 20 years, the prevalence of sexual content has increased in video games with a 'Teen' or 'Mature' rating. Further studies are needed to quantify the potential association between sexual content in video games and sexual behaviour in children and adolescents.

Soil nematode communities are ecologically more mature beneath late- than early-successional stage biological soil crusts

USGS Publications Warehouse

Darby, B.J.; Neher, D.A.; Belnap, J.

2007-01-01

Biological soil crusts are key mediators of carbon and nitrogen inputs for arid land soils and often represent a dominant portion of the soil surface cover in arid lands. Free-living soil nematode communities reflect their environment and have been used as biological indicators of soil condition. In this study, we test the hypothesis that nematode communities are successionally more mature beneath well-developed, late-successional stage crusts than immature, early-successional stage crusts. We identified and enumerated nematodes by genus from beneath early- and late-stage crusts from both the Colorado Plateau, Utah (cool, winter rain desert) and Chihuahuan Desert, New Mexico (hot, summer rain desert) at 0-10 and 10-30 cm depths. As hypothesized, nematode abundance, richness, diversity, and successional maturity were greater beneath well-developed crusts than immature crusts. The mechanism of this aboveground-belowground link between biological soil crusts and nematode community composition is likely the increased food, habitat, nutrient inputs, moisture retention, and/or environmental stability provided by late-successional crusts. Canonical correspondence analysis of nematode genera demonstrated that nematode community composition differed greatly between geographic locations that contrast in temperature, precipitation, and soil texture. We found unique assemblages of genera among combinations of location and crust type that reveal a gap in scientific knowledge regarding empirically derived characterization of dominant nematode genera in deserts soils and their functional role in a crust-associated food web. ?? 2006 Elsevier B.V. All rights reserved.

Risk factors for development of sexually abusive behaviour in sexually victimised adolescent boys: cross sectional study

PubMed Central

Skuse, David; Bentovim, Arnon; Hodges, Jill; Stevenson, Jim; Andreou, Chriso; Lanyado, Monica; New, Michelle; Williams, Bryn; McMillan, Dean

1998-01-01

Objective: To identify factors that may increase the risk of a sexually victimised adolescent boy developing sexually abusive behaviour. Design: Sexually victimised boys who had sexually abused other children were compared with sexually victimised boys who had not done so. Setting: Social services departments in south east England were invited to refer sexually abused and sexually abusing boys to a London postgraduate teaching hospital. Subjects: 25 adolescent boys aged between 11 years and 15 years and 11 months. Main outcome measures: Adjusted odds ratios estimated from unconditional logistic regression. Results: Unadjusted odds rations for witnessing (8.1) as well as experiencing (18.0) intrafamilial violence and discontinuity of care (7.2) discriminated boys who had sexually abused from others who were solely victims of sexual abuse. Only the adjusted odds ratios for witnessing intrafamilial violence (39.7) discriminated the two groups. Conclusions: The risk of adolescent boys who have been victims of sexual abuse engaging in sexually abusive behaviour towards other children is increased by life circumstances which may be unrelated directly to the original abusive experience, in particular exposure to a climate of intrafamilial violence. Our findings have implications for the management of boys found to have been sexually abused and raise important questions about the possibility of secondary prevention of subsequent abusive behaviour in those at greatest risk. Key messages The risk of sexually abused boys in early adolescence abusing other children may be associated with experiences in early life that are independent of sexual victimisation Exposure to persistent violence within the family may be a particularly important risk factor Management of sexually abused boys should take into account the impact of early life experiences that may be associated with increased risk with a view to the secondary prevention of sexually abusive behaviour PMID:9665896

Social and emotional consequences of refraining from sexual activity among sexually experienced and inexperienced youths in California.

PubMed

Brady, Sonya S; Halpern-Felsher, Bonnie L

2008-01-01

We examined the social and emotional consequences among adolescents of refraining from sexual activity (oral or vaginal sex) and whether these consequences differed over time and by gender and sexual experience. Adolescents (N=612; 58% female) recruited from 2 schools were assessed at 4 time points separated by 6-month intervals, beginning in fall of ninth grade. The percentage of adolescents who reported only positive consequences (e.g., they felt responsible, friends were proud) dramatically decreased over time, whereas the percentage that reported negative consequences (e.g., they felt left out, partners became angry) steadily increased. Adolescent girls and sexually experienced adolescents were more likely to report both positive and negative consequences than were adolescent boys and sexually inexperienced adolescents. Adolescents who began the study with sexual experience were more likely to report positive consequences of refraining from sexual activity by the end of the study than those who initiated sexual activity later. Sexual education programs should address how adolescents can cope with or prevent negative consequences of refraining from sexual activity, so that decisions to abstain are rewarding and decisions to engage in sexual activity are motivated by maturity and readiness.

Peer sexual harassment and disordered eating in early adolescence.

PubMed

Petersen, Jennifer L; Hyde, Janet S

2013-01-01

Peer sexual harassment is a pervasive problem in schools and is associated with a variety of negative mental health outcomes. Objectification theory suggests that sexual attention in the form of peer harassment directs unwanted attention to the victim's body and may lead to a desire to alter the body via disordered eating. In the current study, we used latent growth modeling with a sample of 406 U.S. adolescents to examine the relationship between longitudinal trends in peer sexual harassment from 5th to 9th grade and disordered eating in 9th grade. Longitudinal trends in self-surveillance were proposed as a mediator of the relationships. Results indicated that the relationship between upsetting sexual harassment at 5th grade and disordered eating symptoms at 9th grade was mediated by self-surveillance at 5th grade. Girls reported more upsetting sexual harassment, more self-surveillance, and thus more disordered eating than boys did. These results are in accord with objectification theory, which proposes that sexual harassment is a form of sexual objectification and may lead to self-surveillance and disordered eating.

Maturation of the human fetal startle response: evidence for sex-specific maturation of the human fetus.

PubMed

Buss, Claudia; Davis, Elysia Poggi; Class, Quetzal A; Gierczak, Matt; Pattillo, Carol; Glynn, Laura M; Sandman, Curt A

2009-10-01

Despite the evidence for early fetal experience exerting programming influences on later neurological development and health risk, very few prospective studies of human fetal behavior have been reported. In a prospective longitudinal study, fetal nervous system maturation was serially assessed by monitoring fetal heart rate (FHR) responses to vibroacoustic stimulation (VAS) in 191 maternal/fetal dyads. Responses were not detected at 26 weeks gestational age (GA). Sex-specific, age-characteristic changes in the FHR response to VAS were observed by 31 weeks' GA. Males showed larger responses and continued to exhibit maturational changes until 37 weeks' GA, females however, presented with a mature FHR startle response by 31 weeks' GA. The results indicate that there are different rates of maturation in the male and female fetuses that may have implications for sex-specific programming influences.

A Model of Female Sexual Desire: Internalized Working Models of Parent-Child Relationships and Sexual Body Self-Representations.

PubMed

Cherkasskaya, Eugenia; Rosario, Margaret

2017-11-01

The etiology of low female sexual desire, the most prevalent sexual complaint in women, is multi-determined, implicating biological and psychological factors, including women's early parent-child relationships and bodily self-representations. The current study evaluated a model that hypothesized that sexual body self-representations (sexual subjectivity, self-objectification, genital self-image) explain (i.e., mediate) the relation between internalized working models of parent-child relationships (attachment, separation-individuation, parental identification) and sexual desire in heterosexual women. We recruited 614 young, heterosexual women (M = 25.5 years, SD = 4.63) through social media. The women completed an online survey. Structural equation modeling was used. The hypotheses were supported in that the relation between internalized working models of parent-child relationships (attachment and separation-individuation) and sexual desire was mediated by sexual body self-representations (sexual body esteem, self-objectification, genital self-image). However, parental identification was not related significantly to sexual body self-representations or sexual desire in the model. Current findings demonstrated that understanding female sexual desire necessitates considering women's internalized working models of early parent-child relationships and their experiences of their bodies in a sexual context. Treatment of low or absent desire in women would benefit from modalities that emphasize early parent-child relationships as well as interventions that foster mind-body integration.

Early Adolescent Sexual Debut: The Mediating Role of Working Memory Ability, Sensation Seeking, and Impulsivity

ERIC Educational Resources Information Center

Khurana, Atika; Romer, Daniel; Betancourt, Laura M.; Brodsky, Nancy L.; Giannetta, Joan M.; Hurt, Hallam

2012-01-01

Although deficits in working memory ability have been implicated in suboptimal decision making and risk taking among adolescents, its influence on early sexual initiation has so far not been examined. Analyzing 2 waves of panel data from a community sample of adolescents (N = 347; Mean age[subscript baseline] = 13.4 years), assessed 1 year apart,…

Investigating the effect of child maltreatment on early adolescent peer-on-peer sexual aggression: testing a multiple mediator model in a non-incarcerated sample of Danish adolescents.

PubMed

Bramsen, Rikke Holm; Lasgaard, Mathias; Koss, Mary P; Elklit, Ask; Banner, Jytte

2014-01-01

The aim of the present study was to investigate the relationship between child maltreatment and severe early adolescent peer-on-peer sexual aggression, using a multiple mediator model. The study comprised 330 male Grade 9 students with a mean age of 14.9 years (SD=0.5). Estimates from the mediation model indicated significant indirect effects of child physical abuse on sexual aggression via peer influence and insecure-hostile masculinity. No significant total effect of child sexual abuse and child neglect on sexual aggression was found. Findings of the present study identify risk factors that are potentially changeable and therefore of value in informing the design of prevention programs aiming at early adolescent peer-on-peer sexual aggression in at-risk youth.

Being Sexually Attracted to Minors: Sexual Development, Coping With Forbidden Feelings, and Relieving Sexual Arousal in Self-Identified Pedophiles.

PubMed

Houtepen, Jenny A B M; Sijtsema, Jelle J; Bogaerts, Stefan

2016-01-02

This article aims to provide more insight into pedophilic attraction and risk and protective factors for offending in nonclinical pedophiles. Fifteen participants were interviewed about sexuality, coping, and sexual self-regulation. Many participants struggled with acknowledging pedophilic interest in early puberty and experienced psychological difficulties as a result. Furthermore, many committed sex offenses during adolescence when they were still discovering their feelings. Early recognition of risk factors and early start of interventions seem vital in preventing offending. Moreover, results suggest that risk for offending can be diminished by creating more openness about pedophilia and by providing pedophiles with social support and control.

An informational diversity framework, illustrated with sexually deceptive orchids in early stages of speciation.

PubMed

Smouse, Peter E; Whitehead, Michael R; Peakall, Rod

2015-11-01

Reconstructing evolutionary history for emerging species complexes is notoriously difficult, with newly isolated taxa often morphologically cryptic and the signature of reproductive isolation often restricted to a few genes. Evidence from multiple loci and genomes is highly desirable, but multiple inputs require 'common currency' translation. Here we deploy a Shannon information framework, converting into diversity analogue, which provides a common currency analysis for maternally inherited haploid and bi-parentally inherited diploid nuclear markers, and then extend that analysis to construction of minimum-spanning networks for both genomes. The new approach is illustrated with a quartet of cryptic congeners from the sexually deceptive Australian orchid genus Chiloglottis, still in the early stages of speciation. Divergence is more rapid for haploid plastids than for nuclear markers, consistent with the effective population size differential (N(ep) < (N(en)), but divergence patterns are broadly correlated for the two genomes. There are nevertheless intriguing discrepancies between the emerging plastid and nuclear signals of early phylogenetic radiation of these taxa, and neither pattern is entirely consistent with the available information on the sexual cues used by the orchids to lure the pollinators enforcing reproductive isolation. We describe possible extensions of this methodology to multiple ploidy levels and other types of markers, which should increase the range of application to any taxonomic assemblage in the very early stages of reproductive isolation and speciation. © 2015 John Wiley & Sons Ltd.

Sexoanalysis: a new insight-oriented treatment approach for sexual disorders.

PubMed

Ravart, M; Côté, H

1992-01-01

Sexoanalysis is an innovative therapeutic approach for the treatment of complex sexual disorders. This approach integrates current knowledge on sexual/erotic development pathology within a psychodynamic framework to help patients gain insight on the secondary gains, anxieties, and intrapsychic issues that are at the roots of their sexual problem. The treatment process essentially focuses on the analysis of sexual fantasies and the modification of maladaptive erotic imagery. The present authors present a brief overview of sexoanalytic theory and describe how sexoanalysis can resolve sexual disorders, improve sexual/erotic functioning, and promote sexual maturity. A clinical illustration is provided to help further clarify the sexoanalytic treatment process and demonstrate the use and utility of this promising sexotherapeutic approach.

Forward Genetics Defines Xylt1 as a Key, Conserved Regulator of Early Chondrocyte Maturation and Skeletal Length

PubMed Central

Mis, Emily K.; Liem, Karel F.; Kong, Yong; Schwartz, Nancy B.; Domowicz, Miriam; Weatherbee, Scott D.

2014-01-01

The long bones of the vertebrate body are built by the initial formation of a cartilage template that is later replaced by mineralized bone. The proliferation and maturation of the skeletal precursor cells (chondrocytes) within the cartilage template and their replacement by bone is a highly coordinated process which, if misregulated, can lead to a number of defects including dwarfism and other skeletal deformities. This is exemplified by the fact that abnormal bone development is one of the most common types of human birth defects. Yet, many of the factors that initiate and regulate chondrocyte maturation are not known. We identified a recessive dwarf mouse mutant (pug) from an N-ethyl-N-nitrosourea (ENU) mutagenesis screen. pug mutant skeletal elements are patterned normally during development, but display a ~20% length reduction compared to wild-type embryos. We show that the pug mutation does not lead to changes in chondrocyte proliferation but instead promotes premature maturation and early ossification, which ultimately leads to disproportionate dwarfism. Using sequence capture and high-throughput sequencing, we identified a missense mutation in the Xylosyltransferase 1 (Xylt1) gene in pug mutants. Xylosyltransferases catalyze the initial step in glycosaminoglycan (GAG) chain addition to proteoglycan core proteins, and these modifications are essential for normal proteoglycan function. We show that the pug mutation disrupts Xylt1 activity and subcellular localization, leading to a reduction in GAG chains in pug mutants. The pug mutant serves as a novel model for mammalian dwarfism and identifies a key role for proteoglycan modification in the initiation of chondrocyte maturation. PMID:24161523

Forward genetics defines Xylt1 as a key, conserved regulator of early chondrocyte maturation and skeletal length.

PubMed

Mis, Emily K; Liem, Karel F; Kong, Yong; Schwartz, Nancy B; Domowicz, Miriam; Weatherbee, Scott D

2014-01-01

The long bones of the vertebrate body are built by the initial formation of a cartilage template that is later replaced by mineralized bone. The proliferation and maturation of the skeletal precursor cells (chondrocytes) within the cartilage template and their replacement by bone is a highly coordinated process which, if misregulated, can lead to a number of defects including dwarfism and other skeletal deformities. This is exemplified by the fact that abnormal bone development is one of the most common types of human birth defects. Yet, many of the factors that initiate and regulate chondrocyte maturation are not known. We identified a recessive dwarf mouse mutant (pug) from an N-ethyl-N-nitrosourea (ENU) mutagenesis screen. pug mutant skeletal elements are patterned normally during development, but display a ~20% length reduction compared to wild-type embryos. We show that the pug mutation does not lead to changes in chondrocyte proliferation but instead promotes premature maturation and early ossification, which ultimately leads to disproportionate dwarfism. Using sequence capture and high-throughput sequencing, we identified a missense mutation in the Xylosyltransferase 1 (Xylt1) gene in pug mutants. Xylosyltransferases catalyze the initial step in glycosaminoglycan (GAG) chain addition to proteoglycan core proteins, and these modifications are essential for normal proteoglycan function. We show that the pug mutation disrupts Xylt1 activity and subcellular localization, leading to a reduction in GAG chains in pug mutants. The pug mutant serves as a novel model for mammalian dwarfism and identifies a key role for proteoglycan modification in the initiation of chondrocyte maturation. © 2013 Published by Elsevier Inc.