WorldWideScience

Sample records for pubertal timing effects

  1. The Stability of Perceived Pubertal Timing across Adolescence

    Science.gov (United States)

    Cance, Jessica Duncan; Ennett, Susan T.; Morgan-Lopez, Antonio A.; Foshee, Vangie A.

    2011-01-01

    It is unknown whether perceived pubertal timing changes as puberty progresses or whether it is an important component of adolescent identity formation that is fixed early in pubertal development. The purpose of this study is to examine the stability of perceived pubertal timing among a school-based sample of rural adolescents aged 11 to 17 (N=6,425; 50% female; 53% White). Two measures of pubertal timing were used, stage-normative, based on the Pubertal Development Scale, a self-report scale of secondary sexual characteristics, and peer-normative, a one-item measure of perceived pubertal timing. Two longitudinal methods were used: one-way random effects ANOVA models and latent class analysis. When calculating intraclass correlation coefficients using the one-way random effects ANOVA models, which is based on the average reliability from one time point to the next, both measures had similar, but poor, stability. In contrast, latent class analysis, which looks at the longitudinal response pattern of each individual and treats deviation from that pattern as measurement error, showed three stable and distinct response patterns for both measures: always early, always on-time, and always late. Study results suggest instability in perceived pubertal timing from one age to the next, but this instability is likely due to measurement error. Thus, it may be necessary to take into account the longitudinal pattern of perceived pubertal timing across adolescence rather than measuring perceived pubertal timing at one point in time. PMID:21983873

  2. The Effect of Pubertal and Psychosocial Timing on Adolescents' Alcohol Use: What Role Does Alcohol-Specific Parenting Play?

    Science.gov (United States)

    Schelleman-Offermans, Karen; Knibbe, Ronald A.; Engels, Rutger C. M. E.; Burk, William J.

    2011-01-01

    In scientific literature, early pubertal timing emerges as a risk factor of adolescents' drinking, whereas alcohol-specific rules (the degree to which parents permit their children to consume alcohol in various situations) showed to protect against adolescents' drinking. This study investigated whether alcohol-specific rules mediate and/or…

  3. Effects of Pubertal Timing on Communication Behaviors and Stress Reactivity in Young Women during Conflict Discussions with Their Mothers

    Science.gov (United States)

    Weichold, Karina; Buttig, Sabine; Silbereisen, Rainer K.

    2008-01-01

    Individuation, a process whereby adolescents gain autonomy from their parents while maintaining emotional relatedness, is displayed by characteristic styles of verbal exchanges. Negotiating this developmental transition is often stressful for adolescents and their parents. This study deals with the association between pubertal timing,…

  4. Pubertal Onset in Boys and Girls Is Influenced by Pubertal Timing of Both Parents

    DEFF Research Database (Denmark)

    Wohlfahrt-Veje, Christine; Mouritsen, Annette; Hagen, Casper P

    2016-01-01

    CONTEXT: Epidemiological evidence on maternal and paternal heritability of the wide normal variation within pubertal timing is sparse. OBJECTIVE: We aimed to estimate the impact of parental pubertal timing on the onset of puberty in boys and girls. DESIGN: Annual pubertal examinations of healthy...... children in a longitudinal cohort study. Information on parental timing of puberty (earlier, comparable to, or later compared to peers) and menarche age was retrieved from questionnaires. PARTICIPANTS: A total of 672 girls and 846 boys. MAIN OUTCOME MEASURES: Age at onset of pubic hair (PH2+), breasts (B2......+), and menarche in girls; and PH2+, genital stage (G2+), and testis >3 mL with orchidometer (Tvol3+) in boys. RESULTS: In boys, pubertal onset was significantly associated with pubertal timing of both parents. PH2+ and Tvol3+ were earlier: -11.8 months (95% confidence interval, -16.8, -6.8)/-8.9 (-12.8, -4...

  5. Current Changes in Pubertal Timing: Revised Vision in Relation with Environmental Factors Including Endocrine Disruptors.

    Science.gov (United States)

    Parent, Anne-Simone; Franssen, Delphine; Fudvoye, Julie; Pinson, Anneline; Bourguignon, Jean-Pierre

    2016-01-01

    The aim of this chapter is to revise some common views on changes in pubertal timing. This revision is based on recent epidemiological findings on the clinical indicators of pubertal timing and data on environmental factor effects and underlying mechanisms. A current advancement in timing of female puberty is usually emphasized. It appears, however, that timing is also changing in males. Moreover, the changes are towards earliness for initial pubertal stages and towards lateness for final stages in both sexes. Such observations indicate the complexity of environmental influences on pubertal timing. The mechanisms of changes in pubertal timing may involve both the central neuroendocrine control and peripheral effects at tissues targeted by gonadal steroids. While sufficient energy availability is a clue to the mechanism of pubertal development, changes in the control of both energy balance and reproduction may vary under the influence of common determinants such as endocrine-disrupting chemicals (EDCs). These effects can take place right before puberty as well as much earlier, during fetal and neonatal life. Finally, environmental factors can interact with genetic factors in determining changes in pubertal timing. Therefore, the variance in pubertal timing is no longer to be considered under absolutely separate control by environmental and genetic determinants. Some recommendations are provided for evaluation of EDC impact in the management of pubertal disorders and for possible reduction of EDC exposure along the precautionary principle.

  6. Pubertal Timing and Adolescent Sexual Behavior in Girls

    Science.gov (United States)

    Moore, Sarah R.; Harden, K. Paige; Mendle, Jane

    2014-01-01

    Girls who experience earlier pubertal timing relative to peers also exhibit earlier timing of sexual intercourse and more unstable sexual relationships. Although pubertal development initiates feelings of physical desire, the transition into romantic and sexual relationships involves complex biological and social processes contributing both to…

  7. Pubertal timing and adolescent sexual behavior in girls.

    Science.gov (United States)

    Moore, Sarah R; Harden, K Paige; Mendle, Jane

    2014-06-01

    Girls who experience earlier pubertal timing relative to peers also exhibit earlier timing of sexual intercourse and more unstable sexual relationships. Although pubertal development initiates feelings of physical desire, the transition into romantic and sexual relationships involves complex biological and social processes contributing both to physical maturation and to individual interpretations of pubertal experiences. Using a sample of female sibling pairs (n = 923 pairs) from the National Longitudinal Study of Adolescent Health, the present study investigated associations among menarche and perceived pubertal timing, age of first sexual intercourse (AFI), and adolescent dating and sexual behavior using a behavioral genetic approach. Genetic factors influencing age at menarche and perceived pubertal timing predicted AFI through shared genetic pathways, whereas genetic factors related only to perceived pubertal timing predicted engagement in dating, romantic sex, and nonromantic sex in the previous 18 months. These results suggest that a girl's interpretation of her pubertal timing beyond objective timing is important to consider for the timing and the contexts of romantic and reproductive behavior. PsycINFO Database Record (c) 2014 APA, all rights reserved.

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

    Science.gov (United States)

    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.

  9. Childhood body size and pubertal timing in relation to adult mammographic density phenotype.

    Science.gov (United States)

    Schoemaker, Minouk J; Jones, Michael E; Allen, Steven; Hoare, Jean; Ashworth, Alan; Dowsett, Mitch; Swerdlow, Anthony J

    2017-02-07

    An earlier age at onset of breast development and longer time between pubertal stages has been implicated in breast cancer risk. It is not clear whether associations of breast cancer risk with puberty or predictors of onset of puberty, such as weight and height, are mediated via mammographic density, an important risk factor for breast cancer. We investigated whether childhood body size and pubertal timing and tempo, collected by questionnaire, are associated with percentage and absolute area mammographic density at ages 47-73 years in 1105 women recruited to a prospective study. After controlling for adult adiposity, weight at ages 7 and 11 years was strongly significantly inversely associated with percentage and absolute dense area (p trend density (p trend = 0.016). Later age at menarche and age at when regular periods were established was associated with increased density, but additional adjustment for childhood weight attenuated the association. A longer interval between thelarche and menarche, and between thelarche and regular periods, was associated with increased dense area, even after adjusting for childhood weight (p trend = 0.013 and 0.028, respectively), and was independent of age at pubertal onset. Greater prepubertal weight and earlier pubertal onset are associated with lower adult breast density, but age at pubertal onset does not appear to have an independent effect on adult density after controlling for childhood adiposity. A possible effect of pubertal tempo on density needs further investigation.

  10. Pituitary volume mediates the relationship between pubertal timing and depressive symptoms during adolescence.

    Science.gov (United States)

    Whittle, Sarah; Yücel, Murat; Lorenzetti, Valentina; Byrne, Michelle L; Simmons, Julian G; Wood, Stephen J; Pantelis, Christos; Allen, Nicholas B

    2012-07-01

    Early timing of puberty (i.e., advanced pubertal maturation relative to peers) has been linked to the onset of depressive symptoms during the early adolescent phase. However, the precise neurobiological mechanisms linking early pubertal timing to adolescent depressive symptoms are not clear. We investigated whether the volume of the pituitary gland, a key component of the hypothalamic-pituitary-gonadal (HPG) and hypothalamic-pituitary-adrenal (HPA) axes, mediated the relationship between pubertal timing and depressive symptoms in 155 adolescents (72 females) both cross-sectionally and longitudinally. At baseline (M age 12.7, SD 0.5 years), early pubertal timing predicted larger pituitary gland volume and higher depressive symptoms (especially for girls), but there was no mediation effect. Longitudinally, however, larger pituitary gland volume at baseline was found to mediate the relationship between early pubertal timing and increased depressive symptoms over time (M follow-up period=2.57 years, SD=0.26) for both boys and girls. Our findings suggest that neurobiological mechanisms are partly responsible for the link between early pubertal timing and depressive symptoms in adolescents. We speculate that an enlarged pituitary gland in adolescents with early pubertal timing might be associated with hyperactivation of the hormonal stress response, leading to increased susceptibility to environmental stressors, and subsequent development of depressive symptoms. Given the well-established relationship between increasing depressive symptoms in adolescence and later disorder, these findings have implications for targeted prevention and early intervention strategies for depressive disorders in adolescence. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Early Pubertal Timing and Girls' Problem Behavior: Integrating Two Hypotheses

    Science.gov (United States)

    Stattin, Hakan; Kerr, Margaret; Skoog, Therese

    2011-01-01

    Girls' early pubertal timing has been linked in many studies to behavioral problems such as delinquency and substance use. The theoretical explanations for these links have often involved the girls' peer relationships, but contexts have also been considered important in some explanations. By integrating two theoretical models, the…

  12. Association Between Urinary Phthalates and Pubertal Timing in Chinese Adolescents

    Directory of Open Access Journals (Sweden)

    Huijing Shi

    2015-09-01

    Full Text Available Background: Phthalates are synthetic chemicals and ubiquitous environmental contaminants, with hormonal activity that may alter the course of pubertal development in children. Objectives: To determine whether exposure to phthalate metabolites is associated with timing of pubertal development in a cross-sectional study of a school-based clustered sample of 503 children from a suburban district in Shanghai, China, who were 7–14 years of age at enrollment (2010 October to November. Methods: We analyzed six phthalate metabolites in urine samples by isotope-dilution liquid chromatography tandem mass spectrometry. The associations of exposures to phthalates with pubertal timing of testes, breast, and pubic hair development (represented as Tanner stages were evaluated using an ordered logistic regression model adjusted for chronological age, body fat proportion (BF%, and parental education. Results: In boys, urinary mono-n-butyl phthalate (MBP levels were negatively associated with testicular volume, and mono (2-ethyl-5-hydroxyhexyl phthalate (MEHHP and mono (2-ethyl-5-oxohexyl phthalate (MEOHP levels were negatively associated with pubic hair stages. The odds of being in an advanced stage were decreased by 43%–51%. In girls, mono (2-ethylhexyl phthalate (MEHP, MEHHP, and MEOHP levels, as well as the sum of these levels, were positively associated with breast stages, and the association was much stronger in girls with high BF%; the odds of being in an advanced stage were increase by 29% to 50%. Conclusions: Phthalate metabolites investigated in this study show significant associations with pubertal timing both in boys and in girls, especially among girls with high BF%.

  13. Pubertal status, pre-meal drink composition, and later meal timing interact in determining children's appetite and food intake.

    Science.gov (United States)

    Patel, Barkha P; Hamilton, Jill K; Vien, Shirley; Thomas, Scott G; Anderson, G Harvey

    2016-09-01

    Puberty is a period of development that alters energy intake patterns. However, few studies have examined appetite and food intake (FI) regulation during development of puberty in children and adolescents. Therefore, the objective was to measure the effect of pubertal status on FI and subjective appetite after pre-meal glucose and whey protein drinks in 9- to 14-year-old boys and girls. In a within-subject, randomized, repeated-measures design, children (21 pre-early pubertal, 15 mid-late pubertal) received equally sweetened drinks containing Sucralose (control), glucose, or whey protein (0.75 g/kg body weight) in 250 mL of water 2 h after a standardized breakfast on 6 separate mornings. Ad libitum FI was measured either 30 or 60 min later and appetite was measured over time. In pre-early and mid-late pubertal boys and girls there was no effect of sex on total FI (kcal). Glucose and whey protein drinks reduced calorie intake similarly at 30 min. But at 60 min, whey protein reduced FI (p children, but not in mid-late pubertal children. However, sex was a factor (p = 0.041) when FI was expressed per kilogram body weight. Pubertal status did not affect FI/kilogram body weight in boys, but it was 32% lower in mid-late pubertal girls than at pre-early puberty (p = 0.010). Appetite was associated with FI in mid-late pubertal children only. In conclusion, pubertal development affects appetite and FI regulation in children.

  14. Modeling pubertal timing and tempo and examining links to behavior problems.

    Science.gov (United States)

    Beltz, Adriene M; Corley, Robin P; Bricker, Josh B; Wadsworth, Sally J; Berenbaum, Sheri A

    2014-12-01

    Research on the role of puberty in adolescent psychological development requires attention to the meaning and measurement of pubertal development. Particular questions concern the utility of self-report, the need for complex models to describe pubertal development, the psychological significance of pubertal timing vs. tempo, and sex differences in the nature and psychological significance of pubertal development. We used longitudinal self-report data to model linear and logistic trajectories of pubertal development, and used timing and tempo estimates from these models, and from traditional approaches (age at menarche and time from onset of breast development to menarche), to predict psychological outcomes of internalizing and externalizing behavior problems, and early sexual activity. Participants (738 girls, 781 boys) reported annually from ages 9 through 15 on their pubertal development, and they and their parents reported on their behavior in mid-to-late adolescence and early adulthood. Self-reports of pubertal development provided meaningful data for both boys and girls, producing good trajectories, and estimates of individuals' pubertal timing and tempo. A logistic model best fit the group data. Pubertal timing was estimated to be earlier in the logistic compared to linear model, but linear, logistic, and traditional estimates of pubertal timing correlated highly with each other and similarly with psychological outcomes. Pubertal tempo was not consistently estimated, and associations of tempo with timing and with behavior were model dependent. Advances in modeling facilitate the study of some questions about pubertal development, but assumptions of the models affect their utility in psychological studies. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  15. Pubertal timing and adult obesity and cardiometabolic risk in women and men: a systematic review and meta-analysis.

    Science.gov (United States)

    Prentice, P; Viner, R M

    2013-08-01

    Obesity has complex multifactorial aetiology. It has been suggested by many, but not all, reports that earlier pubertal maturation may increase adult obesity risk. We conducted a systemic review and meta-analysis in both women and men, and hypothesised that any association between pubertal timing and adult obesity is likely to be confounded by childhood adiposity. In addition, we investigated whether pubertal timing is related to other cardiometabolic risk and long-term cardiovascular morbidity/mortality. Literature search was undertaken using MEDLINE, EMBASE, Web of Knowledge and TRIP databases, with a hand search of references. Both authors independently reviewed and extracted pre-defined data from all selected papers. Meta-analyses were conducted using Review Manager (RevMan) 5.0.24. A total of 48 papers were identified. Out of 34 studies, 30 reported an inverse relationship between pubertal timing and adult body mass index (BMI), the main adiposity measure used. Meta-analysis of 10 cohorts showed association between early menarche (menarche metabolic syndrome (MetS) and abnormal glycaemia. Earlier pubertal timing is predictive of higher adult BMI and greater risk of obesity. This effect appears to be partially independent of childhood BMI. Earlier pubertal development appears to also be inversely correlated with risk of other cardiometabolic risk factors and cardiovascular mortality. Further work is needed to examine potential mechanisms and the level at which interventions may be targeted.

  16. Pubertal Timing and Depressive Symptoms in Early Adolescents: The Roles of Romantic Competence and Romantic Experiences

    Science.gov (United States)

    Stroud, Catherine B.; Davila, Joanne

    2008-01-01

    In spite of the large literature supporting the link between early pubertal timing and depression in adolescent girls, there are some exceptions. This suggests that there may be factors that interact with pubertal timing, increasing risk for depression in some girls, but not others. This study examined two such factors, romantic competence and…

  17. Ethnicity, Perceived Pubertal Timing, Externalizing Behaviors, and Depressive Symptoms among Black Adolescent Girls

    Science.gov (United States)

    Carter, Rona; Caldwell, Cleopatra Howard; Matusko, Niki; Antonucci, Toni; Jackson, James S.

    2011-01-01

    An accumulation of research evidence suggests that early pubertal timing plays a significant role in girls' behavioral and emotional problems. If early pubertal timing is a problematic event, then early developing Black girls should manifest evidence of this crisis because they tend to be the earliest to develop compared to other girls from…

  18. Recent changes in pubertal timing in healthy Danish boys

    DEFF Research Database (Denmark)

    Sørensen, K; Aksglæde, Lise; Petersen, Jørgen Holm;

    2010-01-01

    In the 1990s, the American population-based study NHANES III renewed the focus on possible secular trends in male puberty. However, no conclusions could be made on pubertal onset due to the lack of compatible data....

  19. Off-Time Pubertal Timing Predicts Physiological Reactivity to Postpuberty Interpersonal Stress

    Science.gov (United States)

    Smith, Anne Emilie; Powers, Sally I.

    2009-01-01

    We investigated associations between retrospectively assessed timing of pubertal development, interpersonal interactions, and hypothalamic-pituitary-adrenal axis reactivity to an interpersonal stress task in 110 young adult women. Participants provided salivary cortisol samples at points prior and subsequent to a video-taped conflict discussion…

  20. Sex 'n' drugs 'n' rock 'n' roll: the meaning and social consequences of pubertal timing.

    Science.gov (United States)

    Waylen, Andrea; Wolke, Dieter

    2004-11-01

    This is a brief review of the normal changes in adolescent behaviour and the interplay between biology and social factors that occur at and around puberty, in an attempt to explain when this transition may become problematic The onset of puberty is a biological marker for an individual's transition from a non-reproductive to a reproductive state. Adolescence is a normal developmental transition associated with clearly visible physical changes, reorganization and pruning of neuronal circuits in the brain and the occurrence of new behaviours and interests. It is a time when new life tasks (orientation towards peers of the other sex, romantic and sexual involvement and mastering an educational career) need to be mastered. Parent-child conflict increases and becomes more intense as the adolescent struggles for more independence while still requiring support. These normal changes can become problematic if biological and social expectations diverge e.g. entering puberty very early or very late. While early pubertal onset in boys is likely to have beneficial effects, in girls precocious pubertal timing may have a negative impact on body-image, affect (or emotional well-being) and sex-role expectations. Other individual biological predispositions and genetic endowment may interact with social factors (e.g. peers, parenting style, neighbourhood) making adolescence either an adaptive or a challenging transition. There is a lack of sufficiently large longitudinal studies that have been able to study this interaction between genetics, biology and social environment on adolescent development. The Avon Longitudinal Study of Parents and Children (ALSPAC) cohort provides a unique opportunity to investigate the impact of pubertal timing on social behaviour. Planned assessments and concepts are outlined.

  1. Dioxin and Polychlorinated Biphenyl Concentrations in Mother's Serum and the Timing of Pubertal Onset in Sons

    Science.gov (United States)

    Humblet, Olivier; Williams, Paige L.; Korrick, Susan A.; Sergeyev, Oleg; Emond, Claude; Birnbaum, Linda S.; Burns, Jane S.; Altshul, Larisa; Patterson, Donald G.; Turner, Wayman E.; Lee, Mary M.; Revich, Boris; Hauser, Russ

    2013-01-01

    Background Animal studies have demonstrated that timing of pubertal onset can be altered by prenatal exposure to dioxins or polychlorinated biphenyls (PCBs), but studies of human populations have been quite limited. Methods We assessed the association between maternal serum concentrations of dioxins and PCBs and the sons’ age of pubertal onset in a prospective cohort of 489 mother–son pairs from Chapaevsk, Russia, a town contaminated with these chemicals during past industrial activity. The boys were recruited at ages 8 to 9 years, and 4 years of annual follow-up data were included in the analysis. Serum samples were collected at enrollment from both mothers and sons for measurement of dioxin and PCB concentrations using high-resolution mass spectrometry. The sons’ pubertal onset—defined as pubertal stage 2 or higher for genitalia (G) or pubic hair (P), or testicular volume >3 mL—was assessed annually by the same physician. Results In multivariate Cox models, elevated maternal serum PCBs were associated with earlier pubertal onset defined by stage G2 or higher (4th quartile hazard ratio = 1.7 [95% confidence interval = 1.1– 2.5]), but not for stage P2 or higher or for testicular volume >3 mL. Maternal serum concentrations of dioxin toxic equivalents were not consistently associated with the sons’ pubertal onset, although a dose-related delay in pubertal onset (only for G2 or higher) was seen among boys who breast-fed for 6 months or more. Conclusions Maternal PCB serum concentrations measured 8 or 9 years after sons’ births—which may reflect sons’ prenatal and early-life exposures—were associated with acceleration in some, but not all, measures of pubertal onset. PMID:21968773

  2. Developmental variations in environmental influences including endocrine disruptors on pubertal timing and neuroendocrine control: Revision of human observations and mechanistic insight from rodents.

    Science.gov (United States)

    Parent, Anne-Simone; Franssen, Delphine; Fudvoye, Julie; Gérard, Arlette; Bourguignon, Jean-Pierre

    2015-07-01

    Puberty presents remarkable individual differences in timing reaching over 5 years in humans. We put emphasis on the two edges of the age distribution of pubertal signs in humans and point to an extended distribution towards earliness for initial pubertal stages and towards lateness for final pubertal stages. Such distortion of distribution is a recent phenomenon. This suggests changing environmental influences including the possible role of nutrition, stress and endocrine disruptors. Our ability to assess neuroendocrine effects and mechanisms is very limited in humans. Using the rodent as a model, we examine the impact of environmental factors on the individual variations in pubertal timing and the possible underlying mechanisms. The capacity of environmental factors to shape functioning of the neuroendocrine system is thought to be maximal during fetal and early postnatal life and possibly less important when approaching the time of onset of puberty.

  3. Genome-wide Association and Longitudinal Analyses Reveal Genetic Loci Linking Pubertal Height Growth, Pubertal Timing, and Childhood Adiposity

    DEFF Research Database (Denmark)

    Cousminer, Diana L; Berry, Diane J; Timpson, Nicholas J

    2013-01-01

    and adverse cardiometabolic health. The only gene so far associated with pubertal height growth, LIN28B, pleiotropically influences childhood growth, puberty, and cancer progression, pointing to shared underlying mechanisms.To discover genetic loci influencing pubertal height and growth and place them...

  4. The Role of Pubertal Timing in What Adolescent Boys Do Online

    Science.gov (United States)

    Skoog, Therese; Stattin, Hakan; Kerr, Margaret

    2009-01-01

    The aim of this study was to investigate associations between pubertal timing and boys' Internet use, particularly their viewing of pornography. We used a sample comprising of 97 boys in grade 8 (M age, 14.22 years) from two schools in a medium-sized Swedish town. This age should be optimal for differentiating early, on-time, and later-maturing…

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

    Science.gov (United States)

    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…

  6. Early adolescent boys’ exposure to Internet pornography: relationships to pubertal timing, sensation seeking, and academic performance

    NARCIS (Netherlands)

    I. Beyens; L. Vandenbosch; S. Eggermont

    2014-01-01

    Research has demonstrated that adolescents regularly use Internet pornography. This two-wave panel study aimed to test an integrative model in early adolescent boys (Mage = 14.10; N = 325) that (a) explains their exposure to Internet pornography by looking at relationships with pubertal timing and s

  7. Pubertal Timing and Mexican-Origin Girls' Internalizing and Externalizing Symptoms: The Influence of Harsh Parenting

    Science.gov (United States)

    Deardorff, Julianna; Cham, Heining; Gonzales, Nancy A.; White, Rebecca M. B.; Tein, Jenn-Yun; Wong, Jessie J.; Roosa, Mark W.

    2013-01-01

    Early-maturing girls are at risk for internalizing and externalizing problems. Research concerning pubertal timing and mental health among Mexican Americans or the influence of parenting behaviors on these relations has been scarce. This study addressed these gaps. This was a prospective examination of 362 Mexican-origin girls and their mothers in…

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

    Science.gov (United States)

    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…

  9. Early Adolescent Boys' Exposure to Internet Pornography: Relationships to Pubertal Timing, Sensation Seeking, and Academic Performance

    Science.gov (United States)

    Beyens, Ine; Vandenbosch, Laura; Eggermont, Steven

    2015-01-01

    Research has demonstrated that adolescents regularly use Internet pornography. This two-wave panel study aimed to test an integrative model in early adolescent boys (M[subscript age] = 14.10; N = 325) that (a) explains their exposure to Internet pornography by looking at relationships with pubertal timing and sensation seeking, and (b) explores…

  10. Early Pubertal Timing and the Union Formation Behaviors of Young Women

    Science.gov (United States)

    Cavanagh, Shannon E.

    2011-01-01

    This study examined whether the transition into adolescence, proxied by pubertal timing, shaped the transition into adulthood, proxied by union formation behaviors, among contemporary American women. In a sample drawn from Add Health (n = 7,523), early maturing girls reported an accelerated transition to marriage and cohabitation in young…

  11. Early adolescent boys’ exposure to Internet pornography: relationships to pubertal timing, sensation seeking, and academic performance

    NARCIS (Netherlands)

    Beyens, I.; Vandenbosch, L.; Eggermont, S.

    2015-01-01

    Research has demonstrated that adolescents regularly use Internet pornography. This two-wave panel study aimed to test an integrative model in early adolescent boys (Mage = 14.10; N = 325) that (a) explains their exposure to Internet pornography by looking at relationships with pubertal timing and s

  12. Early Adolescent Boys' Exposure to Internet Pornography: Relationships to Pubertal Timing, Sensation Seeking, and Academic Performance

    Science.gov (United States)

    Beyens, Ine; Vandenbosch, Laura; Eggermont, Steven

    2015-01-01

    Research has demonstrated that adolescents regularly use Internet pornography. This two-wave panel study aimed to test an integrative model in early adolescent boys (M[subscript age] = 14.10; N = 325) that (a) explains their exposure to Internet pornography by looking at relationships with pubertal timing and sensation seeking, and (b) explores…

  13. Subjective Age in Early Adolescence: Relationships with Chronological Age, Pubertal Timing, Desired Age, and Problem Behaviors

    Science.gov (United States)

    Hubley, Anita M.; Arim, Rubab G.

    2012-01-01

    Subjective age generally refers to the age that one feels. In a cross-sectional questionnaire study of 245 adolescents ages 10-14 years, we examined (a) whether, and when, a cross-over in subjective age occurs, (b) differences in subjective age among pubertal timing groups, (c) correlations between subjective age and each of desired age and five…

  14. Associations of Peripubertal Serum Dioxin and Polychlorinated Biphenyl Concentrations with Pubertal Timing among Russian Boys.

    Science.gov (United States)

    Burns, Jane S; Lee, Mary M; Williams, Paige L; Korrick, Susan A; Sergeyev, Oleg; Lam, Thuy; Revich, Boris; Hauser, Russ

    2016-11-01

    Dioxins, furans, and polychlorinated biphenyls (PCBs), dioxin-like and non-dioxin-like, have been linked to alterations in puberty. We examined the association of peripubertal serum levels of these compounds [and their toxic equivalents (TEQs)] with pubertal onset and maturity among Russian boys enrolled at ages 8-9 years and followed prospectively through ages 17-18 years. At enrollment, 473 boys had serum dioxin-like compounds and PCBs measured. At the baseline visit and annually until age 17-18 years, a physician performed pubertal staging [genitalia (G), pubarche (P), and testicular volume (TV)]. Three hundred fifteen subjects completed the follow-up visit at 17-18 years of age. Pubertal onset was defined as TV > 3 mL, G2, or P2. Sexual maturity was defined as TV ≥ 20 mL, G5, or P5. Multivariable interval-censored models were used to evaluate associations of lipid-standardized concentrations with pubertal timing. Medians (interquartile ranges) of the sum of dioxin-like compounds, TEQs, and non-dioxin-like PCBs were 362 pg/g lipid (279-495), 21.1 pg TEQ/g lipid (14.4-33.2), and 250 ng/g lipid (164-395), respectively. In adjusted models, the highest compared to lowest TEQ quartile was associated with later pubertal onset [TV = 11.6 months (95% CI: 3.8, 19.4); G2 = 10.1 months (95% CI: 1.4, 18.8)] and sexual maturity [TV = 11.6 months (95% CI: 5.7, 17.6); G5 = 9.7 months (95% CI: 3.1, 16.2)]. However, the highest compared to the lowest quartile of non-dioxin-like PCBs, when co-adjusted by TEQs, was associated with earlier pubertal onset [TV = -8.3 months (95% CI:-16.2, -0.3)] and sexual maturity [TV = -6.3 months (95% CI:-12.2, -0.3); G5 = -7.2 months (95% CI:-13.8, -0.6)]; the non-dioxin-like PCB associations were only significant when adjusted for TEQs. TEQs and PCBs were not significantly associated with pubic hair development. Our results suggest that TEQs may delay, while non-dioxin-like PCBs advance, the timing of male puberty. Citation: Burns JS, Lee MM

  15. Coping and coping effectiveness in relation to a competitive sport event: pubertal status, chronological age, and gender among adolescent athletes.

    Science.gov (United States)

    Nicholls, Adam; Polman, Remco; Morley, David; Taylor, Natalie J

    2009-06-01

    An aim of this paper was to discover whether athletes of different pubertal status, chronological age, and gender reported distinct coping strategies in response to stress during a competitive event in their sport. A secondary aim was to examine pubertal status group, chronological age, and gender differences in coping effectiveness. Participants were adolescent athletes (n = 527), classified as beginning-pubertal (n = 59), midpubertal (n = 189), advanced-pubertal (n = 237), and postpubertal (n = 22). Findings revealed that there were small, but significant differences in how athletes of different pubertal status and chronological age coped. There were also significant differences between how athletes of different pubertal status perceived the effectiveness of their coping strategies. Interestingly, our results suggested that the relationship between pubertal status and coping and coping effectiveness is different from the relationship between chronological age and coping and coping effectiveness.

  16. Genome-wide association and longitudinal analyses reveal genetic loci linking pubertal height growth, pubertal timing and childhood adiposity

    NARCIS (Netherlands)

    Cousminer, Diana L.; Berry, Diane J.; Timpson, Nicholas J.; Ang, Wei; Thiering, Elisabeth; Byrne, Enda M.; Taal, H. Rob; Huikari, Ville; Bradfield, Jonathan P.; Kerkhof, Marjan; Groen-Blokhuis, Maria M.; Kreiner-Moller, Eskil; Marinelli, Marcella; Holst, Claus; Leinonen, Jaakko T.; Perry, John R. B.; Surakka, Ida; Pietilainen, Olli; Kettunen, Johannes; Anttila, Verneri; Kaakinen, Marika; Sovio, Ulla; Pouta, Anneli; Das, Shikta; Lagou, Vasiliki; Power, Chris; Prokopenko, Inga; Evans, David M.; Kemp, John P.; St Pourcain, Beate; Ring, Susan; Palotie, Aarno; Kajantie, Eero; Osmond, Clive; Lehtimaki, Terho; Viikari, Jorma S.; Kahonen, Mika; Warrington, Nicole M.; Lye, Stephen J.; Palmer, Lyle J.; Tiesler, Carla M. T.; Flexeder, Claudia; Montgomery, Grant W.; Medland, Sarah E.; Hofman, Albert; Hakonarson, Hakon; Guxens, Monica; Bartels, Meike; Salomaa, Veikko; Murabito, Joanne M.; Kaprio, Jaakko; Sorensen, Thorkild I. A.; Ballester, Ferran; Bisgaard, Hans; Boomsma, Dorret I.; Koppelman, Gerard H.; Grant, Struan F. A.; Jaddoe, Vincent W. V.; Martin, Nicholas G.; Heinrich, Joachim; Pennell, Craig E.; Raitakari, Olli T.; Eriksson, Johan G.; Smith, George Davey; Hypponen, Elina; Jarvelin, Marjo-Riitta; McCarthy, Mark I.; Ripatti, Samuli; Widen, Elisabeth

    2013-01-01

    The pubertal height growth spurt is a distinctive feature of childhood growth reflecting both the central onset of puberty and local growth factors. Although little is known about the underlying genetics, growth variability during puberty correlates with adult risks for hormone-dependent cancer and

  17. Sex differences in time to task failure during early pubertal development.

    Science.gov (United States)

    Rudroff, Thorsten; Holmes, Matthew R; Melanson, Edward L; Kelsey, Megan M

    2014-06-01

    We compared fatigability and activation of elbow flexor muscles in children at 3 pubertal stages during a sustained submaximal contraction. In 72 healthy children (39 boys) aged 11 ± 3 years (range, 8-14 years), differences in fatigability (time to task failure) and muscle activation were compared at 3 Tanner stages (T1-T3). Time to task failure and muscle activation were similar between boys and girls at prepubertal Tanner stage 1. Time to task failure was briefer for girls than boys at Tanner stages 2 and 3 and was predicted by the coactivation indices and percent body fat in girls. Muscle torque was the only predictor for the time to task failure in boys. Differences in fatigability and muscle coactivation were evident during the initial pubertal stages (T2 and T3), but not before the onset of puberty (T1). Copyright © 2013 Wiley Periodicals, Inc.

  18. The influence of early sexual debut and pubertal timing on psychological distress among Taiwanese adolescents.

    Science.gov (United States)

    Chiao, Chi; Ksobiech, Kate

    2015-01-01

    This study examined the relative influence of early sexual debut (ESD) and pubertal timing on psychological distress from adolescence to young adulthood in Taiwan, a non-Western society with a distinct cultural and family context. Data were from a cohort sample of 15-year-olds (N = 2595) first interviewed in 2000, with four follow-ups during a 7-year period. Psychological distress was assessed by a reduced form of the Symptom Checklist-90 Revised. ESD was defined by first intercourse at age 15 or younger. Multivariate analyses via growth curve modeling found a greater increase in psychological distress over time in adolescents with ESD (β = .28, p influence of both ESD and pubertal timing on distress trajectories, independent of parental and family characteristics.

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

    Science.gov (United States)

    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.

  20. Consequences of Early Life Programing by Genetic and Environmental Influences: A Synthesis Regarding Pubertal Timing.

    Science.gov (United States)

    Roth, Christian L; DiVall, Sara

    2016-01-01

    Sexual maturation is closely tied to growth and body weight gain, suggesting that regulative metabolic pathways are shared between somatic and pubertal development. The pre- and postnatal environment affects both growth and pubertal development, indicating that common pathways are affected by the environment. Intrauterine and early infantile developmental phases are characterized by high plasticity and thereby susceptibility to factors that affect metabolic function as well as related reproductive function throughout life. In children born small for gestational age, poor nutritional conditions during gestation can modify metabolic systems to adapt to expectations of chronic undernutrition. These children are potentially poorly equipped to cope with energy-dense diets and are possibly programmed to store as much energy as possible, causing rapid weight gain with the risk for adult disease and premature onset of puberty. Environmental factors can cause modifications to the genome, so-called epigenetic changes, to affect gene expression and subsequently modify phenotypic expression of genomic information. Epigenetic modifications, which occur in children born small for gestational age, are thought to underlie part of the metabolic programming that subsequently effects both somatic and pubertal development. © 2016 S. Karger AG, Basel.

  1. Effects of programmed physical activity on body composition in post-pubertal schoolchildren.

    Science.gov (United States)

    Farias, Edson Dos Santos; Gonçalves, Ezequiel Moreira; Morcillo, André Moreno; Guerra-Júnior, Gil; Amancio, Olga Maria Silverio

    2015-01-01

    To assess body composition modifications in post-pubertal schoolchildren after practice of a physical activity program during one school year. The sample consisted of 386 students aged between 15 and 17 years and divided into two groups: the study group (SG) comprised 195 students and the control group (CG), 191. The SG was submitted to a physical activity program and the CG attended conventional physical education classes. Body composition was assessed using body mass index (BMI), percentage of body fat (%BF), fat mass (FM), and lean mass (LM). A positive effect of the physical activity program on body composition in the SG (p<0.001) was observed, as well as on the interaction time x group in all the variables analyzed in both genders. A reduction in %BF (mean of differences = -5.58%) and waist circumference (-2.33 cm), as well as an increase in LM (+2.05 kg) were observed in the SG for both genders, whereas the opposite was observed in the CG. The practice of programmed physical activity promotes significant reduction of body fat in post-pubertal schoolchildren. Copyright © 2013 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

  2. Effects of prenatal exposure to a low dose atrazine metabolite mixture on pubertal timing and prostate development of male Long-Evans rats

    Energy Technology Data Exchange (ETDEWEB)

    Stanko, Jason [National Institute of Environmental Health Sciences (NIEHS); Enoch, Rolondo [North Carolina Central University, Durham; Rayner, Jennifer L [ORNL; Davis, Christine [U.S. Environmental Protection Agency; Wolf, Douglas [U.S. Environmental Protection Agency; Malarkey, David [University of North Carolina, Chapel Hill; Fenton, Suzanne [National Institute of Environmental Health Sciences (NIEHS)

    2010-12-01

    The present study examines the postnatal reproductive development of male rats following prenatal exposure to an atrazine metabolite mixture (AMM) consisting of the herbicide atrazine and its environmental metabolites diaminochlorotriazine, hydroxyatrazine, deethylatrazine, and deisopropylatrazine. Pregnant Long-Evans rats were treated by gavage with 0.09, 0.87, or 8.73 mg AMM/kg body weight (BW), vehicle, or 100 mg ATR/kg BW positive control, on gestation days 15 19. Preputial separation was significantly delayed in 0.87 mg and 8.73 mg AMM-exposed males. AMM-exposed males demonstrated a significant treatment-related increase in incidence and severity of inflammation in the prostate on postnatal day (PND) 120. A dose-dependent increase in epididymal fat masses and prostate foci were grossly visible in AMM-exposed offspring. These results indicate that a short, late prenatal exposure to mixture of chlorotriazine metabolites can cause chronic prostatitis in male LE rats. The mode of action for these effects is presently unclear.

  3. Effects of Di-(2-ethylhexyl) Phthalate on the Hypothalamus-Uterus in Pubertal Female Rats.

    Science.gov (United States)

    Liu, Te; Jia, Yiyang; Zhou, Liting; Wang, Qi; Sun, Di; Xu, Jin; Wu, Juan; Chen, Huaiji; Xu, Feng; Ye, Lin

    2016-11-12

    The pollution of endocrine disruptors and its impact on human reproductive system have attracted much attention. Di-(2-ethylhexyl) phthalate (DEHP), an environmental endocrine disruptor, is widely used in food packages, containers, medical supplies and children's toys. It can cause diseases such as infertility, sexual precocity and uterine bleeding and thus arouse concerns from the society and scholars. The effect of DEHP on pubertal female reproductive system is still not well-studied. This study was to investigate the effects of DEHP on the hypothalamus-uterus in pubertal female rats, reveal the reproductive toxicity of DEHP on pubertal female rats and its mechanism, and provide scientific evidence for the evaluation of toxicity and toxic mechanism of DEHP on reproductive system. Forty-eight pubertal female rats were randomly divided into four groups and respectively administered via oral gavage 0, 250, 500, or 1000 mg/kg/d DEHP in 0.1 mL corn oil/20 g body weight for up to four weeks. Compared with control rats, the DEHP-treated rats showed: (1) higher gonadotropin-releasing hormone (GnRH) level in the hypothalamus; (2) higher protein levels of GnRH in the hypothalamus; and (3) higher mRNA and protein levels of GnRH receptor (GnRHR) in the uterus. Our data reveal that DEHP exposure may lead to a disruption in pubertal female rats and an imbalance of hypothalamus-uterus. Meanwhile, DEHP may, through the GnRH in the hypothalamus and its receptor on the uterus, lead to diseases of the uterus. DEHP may impose a negative influence on the development and functioning of the reproductive system in pubertal female rats.

  4. Pubertal timing and health-related behaviours in adolescence - socio- economic outcomes in a follow-up study from Finland

    Directory of Open Access Journals (Sweden)

    Leena K Koivusilta

    2006-03-01

    Full Text Available

    Background. Pubertal timing is connected with health-related lifestyle in adulthood. We studied whether early or late pubertal timing is predictive of socio-economic outcomes in early adulthood and whether the associations are mediated by health behaviours.

    Methods. Survey data (1981, 1983, 1985, 1987 from samples of 14-year-old Finns (N=4246, response rate 85% were linked with respondents’ attained educational level, socio-economic and labour market position in 2001 (ages 28-34. Ages of menarche and first ejaculation indicated pubertal timing.

    Results. As compared to adolescents with average age pubertal timing, boys and girls maturing at an early age more often participated in health-compromising behaviours, while those maturing at a later age participated less frequently. Pubertal timing was not associated with attained educational level or socioeconomic position in girls and not with labour market position at the time of follow-up in either sex. In boys, independently of health behaviours, early or late onset of puberty predicted low educational level, while late onset predicted low socio-economic position.

    Conclusion. Timing of puberty has a stronger connection with socio-economic outcomes in boys than in girls. Deviance from the normative pace of physical development, especially late maturation, is among boys slightly depicted in the hierarchy of socio-economic positions of the society. As pubertal timing is connected with health-related behaviours – especially with smoking – the pacing of developmental transitions should be considered in planning programmes preventing unhealthy behavioural patterns often linked with negative attitudes towards schooling.

  5. Pubertal development in elite juvenile gymnasts. Effects of physical training.

    Science.gov (United States)

    Lindholm, C; Hagenfeldt, K; Ringertz, B M

    1994-03-01

    Twenty-two female teenagers engaged in elite gymnast training were prospectively studied during a five-year period and their pubertal development was recorded. Height and weight, as well as stage of development according to Tanner, were registered every six months. FSH, LH, TSH and prolactin were measured in girls who had not yet had their first menstrual period. Twenty-two healthy school girls in the same age group who were not actively engaged in physical exercise served as a control group. Pubertal development was completed during the observation period in all the gymnasts but one, who had primary amenorrhea at the age of eighteen. As a group, the gymnasts had a significantly delayed age of menarche compared to the control group and to normal Swedish girls. They also had significantly less body fat and were shorter and lighter than the control group. They grew much more slowly and did not have the distinct growth spurt seen in the controls. The final height of six of the gymnasts was less than the expected height. The frequency of injuries was high in the gymnasts, which might be a result of hard training combined with late menarche and low body fat.

  6. Putative effects of endocrine disrupters on pubertal development in the human

    DEFF Research Database (Denmark)

    Teilmann, Grete; Juul, Anders; Skakkebaek, Niels E

    2002-01-01

    Pubertal development is regulated by gonadotrophins and sex hormones. There has been a clear secular trend in the timing of puberty during the last century, puberty becoming earlier. Although improved nutrition is assumed to be the cause, this could partly be associated with exposure to so-called...

  7. Effect of stress hormone antagonists on ovarian follicular development in pre-pubertal rat

    Directory of Open Access Journals (Sweden)

    Kalid Hamood Abdullah

    2012-08-01

    Full Text Available Effect of stress on pre-pubertal ovarian follicular development was studied. Fifteen day old female rats were administered under stress (exposed to maternal separation; 6 hours/day from post-natal day 15 to 21 for 7 days, and appropriate controls were maintained. The time of exposure was randomly changed every day during light phase (7AM to 7 PM of the day to avoid habituation. There was a significant decrease in serum estrogen levels on post-natal day 21 in stress group rats compared to controls indicating stress response in these rats. However, mean number of healthy follicles in all categories of follicles were significantly lower in stressed rats compared to controls. Concomitant with these changes, mean number of atreitic follicles showed an increase over control values in stressed rats. In contrast administration of Naltrexone (5μg NTX/rat/day, Mifepristone (1 μg MP/rat/day, FSH (10 IU FSH/rat/day with stressed the significant increases in the relative weight of ovary, uterus, fallopian tube, body weight and the mean number of healthy follicles in the ovary compared to the controls. In the ovary treatment of stressed did not affect primordial follicles. Primordial follicles were reduced in number significantly in the ovary of controls and treated groups when compared with the initial controls whereas there was no significant variation among the controls and the treated groups. The results indicate that stress dose not interfere with the progress of pre-pubertal follicular development. However, it causes increased loss of follicles by atretia.

  8. Effects of vitamin A on in vitro maturation of pre-pubertal mouse spermatogonial stem cells.

    Directory of Open Access Journals (Sweden)

    Albanne Travers

    Full Text Available Testicular tissue cryopreservation is the only potential option for fertility preservation in pre-pubertal boys exposed to gonadotoxic treatment. Completion of spermatogenesis after in vitro maturation is one of the future uses of harvested testicular tissue. The purpose of the current study was to evaluate the effects of vitamin A on in vitro maturation of fresh and frozen-thawed mouse pre-pubertal spermatogonial stem cells in an organ culture system. Pre-pubertal CD1 mouse fresh testes were cultured for 7 (D7, 9 (D9 and 11 (D11 days using an organ culture system. Basal medium was supplemented with different concentrations of retinol (Re or retinoic acid (RA alone or in combination. Seminiferous tubule morphology (tubule diameter, intra-tubular cell type, intra-tubular cell death and proliferation (PCNA antibody and testosterone level were assessed at D7, D9 and D11. Pre-pubertal mouse testicular tissue were frozen after a soaking temperature performed at -7 °C, -8 °C or -9 °C and after thawing, were cultured for 9 days, using the culture medium preserving the best fresh tissue functionality. Retinoic acid at 10(-6M and retinol at 3.3.10(-7M, as well as retinol 10(-6M are favourable for seminiferous tubule growth, maintenance of intra-tubular cell proliferation and germ cell differentiation of fresh pre-pubertal mouse spermatogonia. Structural and functional integrity of frozen-thawed testicular tissue appeared to be well-preserved after soaking temperature at -8 °C, after 9 days of organotypic culture using 10(-6M retinol. RA and Re can control in vitro germ cell proliferation and differentiation. Re at a concentration of 10(-6M maintains intra-tubular cell proliferation and the ability of spermatogonia to initiate spermatogenesis in fresh and frozen pre-pubertal mouse testicular tissue using a soaking temperature at -8 °C. Our data suggested a possible human application for in vitro maturation of cryopreserved pre-pubertal testicular

  9. Recent changes in pubertal timing in healthy Danish boys: associations with body mass index

    DEFF Research Database (Denmark)

    Sørensen, Kaspar; Aksglaede, Lise; Petersen, Jørgen Holm;

    2010-01-01

    In the 1990s, the American population-based study NHANES III renewed the focus on possible secular trends in male puberty. However, no conclusions could be made on pubertal onset due to the lack of compatible data....

  10. Sexual differentiation of human behavior: effects of prenatal and pubertal organizational hormones.

    Science.gov (United States)

    Berenbaum, Sheri A; Beltz, Adriene M

    2011-04-01

    A key question concerns the extent to which sexual differentiation of human behavior is influenced by sex hormones present during sensitive periods of development (organizational effects), as occurs in other mammalian species. The most important sensitive period has been considered to be prenatal, but there is increasing attention to puberty as another organizational period, with the possibility of decreasing sensitivity to sex hormones across the pubertal transition. In this paper, we review evidence that sex hormones present during the prenatal and pubertal periods produce permanent changes to behavior. There is good evidence that exposure to high levels of androgens during prenatal development results in masculinization of activity and occupational interests, sexual orientation, and some spatial abilities; prenatal androgens have a smaller effect on gender identity, and there is insufficient information about androgen effects on sex-linked behavior problems. There is little good evidence regarding long-lasting behavioral effects of pubertal hormones, but there is some suggestion that they influence gender identity and perhaps some sex-linked forms of psychopathology, and there are many opportunities to study this issue.

  11. The value of shoe size for prediction of the timing of the pubertal growth spurt

    Directory of Open Access Journals (Sweden)

    Verkerke Gijsbertus J

    2011-01-01

    Full Text Available Abstract Background Knowing the timing of the pubertal growth spurt of the spine, represented by sitting height, is essential for the prognosis and therapy of adolescent idiopathic scoliosis. There are several indicators that reflect growth or remaining growth of the patient. For example, distal body parts have their growth spurt earlier in adolescence, and therefore the growth of the foot can be an early indicator for the growth spurt of sitting height. Shoe size is a good alternative for foot length, since patients can remember when they bought new shoes and what size these shoes were. Therefore the clinician already has access to some longitudinal data at the first visit of the patient to the outpatient clinic. The aim of this study was to describe the increase in shoe size during adolescence and to determine whether the timing of the peak increase could be an early indicator for the timing of the peak growth velocity of sitting height. Methods Data concerning shoe sizes of girls and boys were acquired from two large shoe shops from 1991 to 2008. The longitudinal series of 242 girls and 104 boys were analysed for the age of the "peak increase" in shoe size, as well as the age of cessation of foot growth based on shoe size. Results The average peak increase in shoe size occurred at 10.4 years (SD 1.1 in girls and 11.5 years (SD 1.5 in boys. This was on average 1.3 years earlier than the average peak growth velocity of sitting height in girls, and 2.5 years earlier in boys. The increase in shoe size diminishes when the average peak growth velocity of sitting height takes place at respectively 12.0 (SD 0.8 years in girls, and 13.7 (SD 1.0 years in boys. Conclusions Present data suggest that the course of the shoe size of children visiting the outpatient clinic can be a useful first tool for predicting the timing of the pubertal growth spurt of sitting height, as a representative for spinal length. This claim needs verification by direct

  12. Peer and Individual Risk Factors in Adolescence Explaining the Relationship Between Girls' Pubertal Timing and Teenage Childbearing.

    Science.gov (United States)

    Hendrick, C Emily; Cance, Jessica Duncan; Maslowsky, Julie

    2016-05-01

    Girls with early pubertal timing are at elevated risk for teenage childbearing; however, the modifiable mechanisms driving this relationship are not well understood. The objective of the current study was to determine whether substance use, perceived peer substance use, and older first sexual partners mediate the relationships among girls' pubertal timing, sexual debut, and teenage childbearing. Data are from Waves 1-15 of the female cohort of the National Longitudinal Surveys of Youth 1997 (NLSY97), a nationwide, ongoing cohort study of U.S. men and women born between 1980 and 1984. The analytic sample (n = 2066) was 12-14 years old in 1997 and ethnically diverse (51 % white, 27 % black, 22 % Latina). Using structural equation modeling, we found substance use in early adolescence and perceived peer substance use each partially mediated the relationships among girls' pubertal timing, sexual debut, and teenage childbearing. Our findings suggest early substance use behavior as one modifiable mechanism to be targeted by interventions aimed at preventing teenage childbearing among early developing girls.

  13. Evaluating the Effectiveness of Pubertal Preparedness Program in Terms of Knowledge and Attitude Regarding Pubertal Changes Among Pre-Adolescent Girls

    Directory of Open Access Journals (Sweden)

    Manisha Rani RN

    2016-12-01

    Full Text Available Objective: To compare the knowledge and attitude regarding pubertal changes among pre – adolescent girls before and after the pubertal preparedness program (PPP in experimental and comparison group.Materials and methods: A Quasi experimental (non- equivalent comparison group pretest posttest design was adopted with 104pre-adolescentgirls (52 in each experimental and comparison group of age 12-14years, selected by purposive sampling from two different Government schools of Ambala District. Knowledge and attitude was assessed using structured knowledge questionnaire (KR-20 = 0.74 and 5 point likert scale (Cronbach’s alpha = 0.79 respectively. On the same day of pretest, PPP was administered and on 12th day FAQs reinforcement session was held only for experimental group. After 28 days, posttest was taken.Results: The computed t value of pretest of knowledge and attitude scores of pre-adolescent girls (1.97, (1.95 respectively in experimental and comparison group was found non-significant at 0.05 level of significance which shows that both group didn’t differ significantly in their knowledge and attitude before the administration of intervention. Findings of unpaired ‘t’ value of posttest knowledge and attitude scores of pre-adolescent girls (19.77, (17.17 respectively in experimental and comparison group were found significant at 0.05 level of significance, Thus knowledge and attitude of pre-adolescent girls were improved with PPP and FAQs session.Conclusion: Pubertal preparedness program and FAQs reinforcement session are effective in enhancing knowledge and developing favorable attitude among pre-adolescent girls.

  14. Putative effects of endocrine disrupters on pubertal development in the human

    DEFF Research Database (Denmark)

    Teilmann, Grete; Juul, Anders; Skakkebaek, Niels E

    2002-01-01

    Pubertal development is regulated by gonadotrophins and sex hormones. There has been a clear secular trend in the timing of puberty during the last century, puberty becoming earlier. Although improved nutrition is assumed to be the cause, this could partly be associated with exposure to so......-called endocrine disrupters. Precocious puberty has been described in several case reports of accidental exposure to oestrogenic compounds in cosmetic products, food and pharmaceuticals. Local epidemics of premature thelarche have also been suggested to be linked to endocrine disrupters. Children adopted from...

  15. Pubertal Development, Personality, and Substance Use: A 10-Year Longitudinal Study From Childhood to Adolescence

    Science.gov (United States)

    Castellanos-Ryan, Natalie; Parent, Sophie; Vitaro, Frank; Tremblay, Richard E.; Séguin, Jean R.

    2013-01-01

    Most research linking early pubertal development to substance use has focused on the effects of pubertal timing (age at which a certain stage of pubertal development is reached or pubertal status at a particular age—related to the maturation disparity hypothesis), but little research has focused on pubertal tempo (rate of growth through pubertal stages—related to the maturation compression hypothesis). However, both timing and tempo have not only been identified as important components of pubertal development, with different predictors, but have also been shown to be independently associated with other adolescent psychopathologies. Using latent growth-curve modeling, this study examined how pubertal status at age 12 and pubertal tempo (between 11 and 13 years) related to substance use from 15 to 16 years in boys from low socioeconomic backgrounds (N = 871). Results showed that both pubertal status at age 12 and tempo were significant predictors of increased levels of substance use and problems in mid to late adolescence. In an attempt to identify mechanisms that may explain the association between pubertal development and substance use it was found that sensation seeking partially mediated the association between pubertal status at age 12 and substance use behaviors. Impulse control was found to moderate the association sensation seeking had with marijuana use frequency, with high sensation-seeking scores predicting higher marijuana use frequency only at low levels of impulse control. These findings highlight the importance of considering multiple sources of individual variability in the pubertal development of boys and provide support for both the maturational disparity and compression hypotheses. PMID:24016016

  16. Pubertal development, personality, and substance use: a 10-year longitudinal study from childhood to adolescence.

    Science.gov (United States)

    Castellanos-Ryan, Natalie; Parent, Sophie; Vitaro, Frank; Tremblay, Richard E; Séguin, Jean R

    2013-08-01

    Most research linking early pubertal development to substance use has focused on the effects of pubertal timing (age at which a certain stage of pubertal development is reached or pubertal status at a particular age--related to the maturation disparity hypothesis), but little research has focused on pubertal tempo (rate of growth through pubertal stages--related to the maturation compression hypothesis). However, both timing and tempo have not only been identified as important components of pubertal development, with different predictors, but have also been shown to be independently associated with other adolescent psychopathologies. Using latent growth-curve modeling, this study examined how pubertal status at age 12 and pubertal tempo (between 11 and 13 years) related to substance use from 15 to 16 years in boys from low socioeconomic backgrounds (N = 871). Results showed that both pubertal status at age 12 and tempo were significant predictors of increased levels of substance use and problems in mid to late adolescence. In an attempt to identify mechanisms that may explain the association between pubertal development and substance use it was found that sensation seeking partially mediated the association between pubertal status at age 12 and substance use behaviors. Impulse control was found to moderate the association sensation seeking had with marijuana use frequency, with high sensation-seeking scores predicting higher marijuana use frequency only at low levels of impulse control. These findings highlight the importance of considering multiple sources of individual variability in the pubertal development of boys and provide support for both the maturational disparity and compression hypotheses.

  17. Deleterious effects of obesity on physical fitness in pre-pubertal children.

    Science.gov (United States)

    Ceschia, Arianna; Giacomini, Stefano; Santarossa, Simone; Rugo, Miriam; Salvadego, Desy; Da Ponte, Alessandro; Driussi, Caterina; Mihaleje, Martina; Poser, Stefano; Lazzer, Stefano

    2016-01-01

    The prevalence of obesity in children has increased dramatically during the past decades in Europe and understanding physical fitness and its components in children is critical to design and implement effective interventions. The objective of the present study was to analyse the association between physical fitness (aerobic, speed, agility, power, flexibility and balance) and body mass index (BMI) in pre-pubertal children. A total of 2411 healthy schoolchildren (7-11 years) participated in this study. Anthropometric characteristics and body composition were assessed by skinfold thickness. Physical fitness was measured by nine physical fitness tests: endurance running, 20 m running speed, agility, handgrip strength, standing long jump and squat jump, sit and reach, medicine ball forward throw and static balance. No relevant differences were observed between boys and girls regarding anthropometric characteristics, body composition and physical fitness. However, overweight and obese children showed significantly lower physical fitness levels in endurance running, speed and agility (mean: +18.8, +5.5 and +14.5% of time to complete tasks, respectively), lower limb power normalised to body mass (-23.3%) and balance tests (number of falls: +165.5%) than their normal weight counterparts. On the other hand, obesity did not affect handgrip, throwing and flexibility. In conclusion, increased BMI was associated with lower performance capabilities limiting proper motor skill development, which directly affects the ability of children to take on sports skills. Actions undertaken to promote children's wellness and fitness should be prioritised and introduced early in life with the aim of enhancing physical fitness as well as preventing overweight and obesity.

  18. Adolescents' increasing stress response to social evaluation: pubertal effects on cortisol and alpha-amylase during public speaking.

    Science.gov (United States)

    van den Bos, Esther; de Rooij, Mark; Miers, Anne C; Bokhorst, Caroline L; Westenberg, P Michiel

    2014-01-01

    Stress responses to social evaluation are thought to increase during adolescence, which may be due to pubertal maturation. However, empirical evidence is scarce. This study is the first to investigate the relation between pubertal development and biological responses to a social-evaluative stressor longitudinally. Participants performed the Leiden Public Speaking Task twice, with a 2-year interval (N = 217; age at Time 1: 8-17 years). The results support an increase in sensitivity to social evaluation during adolescence. The overall cortisol and alpha-amylase responses increased-both between and within participants-and were more strongly related to self-reported pubertal development than to age. The cortisol response shifted from speech delivery toward anticipation. The alpha-amylase response increased in both phases. © 2013 The Authors. Child Development © 2013 Society for Research in Child Development, Inc.

  19. 遗传因素对青春期启动时间的调控%Genetics of pubertal timing

    Institute of Scientific and Technical Information of China (English)

    马晓宇

    2010-01-01

    青春期是性成熟并获得生殖能力的重要发育阶段.遗传因素是对个体青春期启动时间影响最大的因素.近来分子遗传学的分析逐渐阐明了一些青春发育时间异常疾病的遗传学基础,例如特发性低促性腺激素性性功能减退症和Kallmann综合征.一般人群青春启动时间变异的遗传学基础成为目前研究的热点,然而迄今为止却没有一个基因位点被证实与性发育时间有关.该文主要阐述与青春期启动时间异常有关的基因学研究进展,并讨论与正常青春期启动时间有关的基因.%Puberty is an important developmental stage that leads to sexual maturation and reproductive capability. Genetic factors play a significant role in regulating the variation of pubertal timing. Recent genetic analysis are increasingly elucidating the genetic basis of disorders of pubertal timing such as hypogonadotropic hypogonadism and Kallmann syndrome. Ongoing studies are also investigating the genetic control of puberty in the general population, although no genetic loci have been reproducibly associated with pubertal timing thus far. This review summarizes an update of the genes implicated in disorders of puberty,discusses genes that may be involved in the timing of normal puberty.

  20. The effect of a complex training and detraining programme on selected strength and power variables in early pubertal boys.

    Science.gov (United States)

    Ingle, Lee; Sleap, Mike; Tolfrey, Keith

    2006-09-01

    Complex training, a combination of resistance training and plyometrics is growing in popularity, despite limited support for its efficacy. In pre- and early pubertal children, the study of complex training has been limited, and to our knowledge an examination of its effect on anaerobic performance characteristics of the upper and lower body has not been undertaken. Furthermore, the effect of detraining after complex training requires clarification. The physical characteristics (mean+/-s) of the 54 male participants in the present study were as follows: age 12.3 +/- 0.3 years, height 1.57 +/- 0.07 m, body mass 50.3 +/- 11.0 kg. Participants were randomly assigned to an experimental (n = 33) or control group (n = 21). The training, which was performed three times a week for 12 weeks, included a combination of dynamic constant external resistance and plyometrics. After training, participants completed 12 weeks of detraining. At baseline, after training and after detraining, peak and mean anaerobic power, dynamic strength and athletic performance were assessed. Twenty-six participants completed the training and none reported any training-related injury. Complex training was associated with small increases ( 0.05). In the experimental group, dynamic strength was increased by 24.3 - 71.4% (dependent on muscle group; P 0.05). For 40-m sprint running, basketball chest pass and vertical jump test performance, the experimental group saw a small improvement ( 0.05). In conclusion, in pre- and early pubertal boys, upper and lower body complex training is a time-effective and safe training modality that confers small improvements in anaerobic power and jumping, throwing and sprinting performance, and marked improvements in dynamic strength. However, after detraining, the benefits of complex training are lost at similar rates to other training modalities.

  1. The organizational effects of pubertal testosterone on sexual proficiency in adult male Syrian hamsters.

    Science.gov (United States)

    De Lorme, Kayla C; Sisk, Cheryl L

    2016-10-15

    Social proficiency requires making appropriate behavioral adaptations as a result of social experience. For example, male rodents become sexually proficient with experience as demonstrated by a reduction in ectopic (misdirected) mounts, mount-to-intromission ratio, and latency to ejaculation. We previously found that over a series of timed tests with a receptive female, male hamsters deprived of testosterone specifically during puberty (NoT@P) have overall lower levels of sexual behavior and continue to display high levels of ectopic mounts, compared with males that experienced endogenous testosterone during puberty (T@P). These results suggested that pubertal testosterone programs sexual proficiency in adulthood, but because NoT@P males engaged in less sexual behavior than T@P males in these tests, the amount of sexual experience may have been insufficient to improve sexual proficiency. To more rigorously test the hypothesis that pubertal testosterone is necessary for social proficiency in adulthood, the present study compared the behavior of NoT@P and T@P males in a series of 4 trials with a 48-h interval between each trial. Sexual experience was equated by limiting each trial to 5 intromissions. Sexually-naïve males were either gonadectomized prepubertally (NoT@P) or in adulthood (T@P) and received subcutaneous testosterone capsules four weeks later. Two weeks after testosterone replacement, these groups and a group of adult gonad-intact controls began sexual behavior testing. We found that NoT@P males had more ectopic mounts/min across all four tests compared to gonad-intact and T@P males. Moreover, both gonad-intact and T@P males, but not NoT@P males, showed an increase in the number of mounts and intromissions/min between trials 1 and 3. Unexpectedly, both gonad-intact and T@P, but not NoT@P, males showed a decrease in sexual behaviors during trial 4. Thus, T@P males display multiple behavioral adaptations to sexual experience that are not observed in No

  2. Effects on steroid hormones secretion resulting from the acute stimulation of sectioning the superior ovarian nerve to pre-pubertal rats

    Directory of Open Access Journals (Sweden)

    Morales-Ledesma Leticia

    2012-10-01

    Full Text Available Abstract In the adult rat, neural signals arriving to the ovary via the superior ovarian nerve (SON modulate progesterone (P4, testosterone (T and estradiol (E2 secretion. The aims of the present study were to analyze if the SON in the pre-pubertal rat also modulates ovarian hormone secretion and the release of follicle stimulating hormone (FSH and luteinizing (LH hormone. P4, T, E2, FSH and LH serum levels were measured 30 or 60 minutes after sectioning the SON of pre-pubertal female rats. Our results indicate that the effects on hormone levels resulting from unilaterally or bilaterally sectioning the SON depends on the analyzed hormone, and the time lapse between surgery and autopsy, and that the treatment yielded asymmetric results. The results also suggest that in the pre-pubertal rat the neural signals arriving to the ovaries via the SON regulate the enzymes participating in P4, T and E2 synthesis in a non-parallel way, indicating that the mechanisms regulating the synthesis of each hormone are not regulated by the same signals. Also, that the changes in the steroids hormones are not explained exclusively by the modifications in gonadotropins secretion. The observed differences in hormone levels between rats sacrificed 30 and 60 min after surgery reflect the onset of the compensatory systems regulating hormones secretion.

  3. EFFECT OF GnRH AND PHOSPHORUS IN DELAYED PUBERTAL SURTI BUFFALO HEIFERS

    Directory of Open Access Journals (Sweden)

    H.B. Dhamsaniya

    2016-06-01

    Full Text Available The study was conducted on eighteen delayed pubertal Surti buffalo heifers, divided into three equal groups (6 in each to evaluate the efficacy of GnRH alone and in combination of phosphorus. The buffalo heifers in Group-I and Group-II were treated with Buserelin acetate (5 ml, IM. Buffalo heifers in Group-II also received additional injection of Toldimphos sodium (10 ml, IM at 3 day interval for 4 times, while buffalo heifers in Group-III served as control. The percentage of induced estrus was highest (83.33% in each treated groups as compared to control group (50%. The mean estrus induction intervals were significantly (P<0.05 shorter in Group-I (20.20 ± 2.18 days and Group-II (18.80 ± 2.32 days as compared to control group (30.24 ± 0.81 days. The conception rate at induced estrus was highest in Group-II (50% followed by Group-I (33.33%. The plasma progesterone levels being significantly lowest on the day of estrus (less than 0.5 ng/ml as compared to pre-treatment days in all groups. The mean total protein and triglycerides levels were differed significantly between the groups on the day of estrus and being significantly higher in Group-II as compared to Group-I and III on that day. A significantly higher level of cholesterol in both treatment groups as compared to the control group during different intervals and also being higher on the day of estrus as compared to pre-treatment days. The mean plasma glucose levels were differed nonsignificantly between and within the treatment and control groups. It is concluded that estrus can be successfully induced in delayed pubertal heifers with the use of GnRH alone and in combination with phosphorus.

  4. Pubertal assessment: targeted educational intervention for pediatric trainees.

    Science.gov (United States)

    Khokhar, Aditi; Nagarajan, Sairaman; Ravichandran, Yagnaram; Perez-Colon, Sheila

    2017-08-18

    Background Timely and periodic pubertal assessment in children is vital to identify puberty related disorders. Pediatricians need to have working knowledge of puberty time and tempo. Pediatric residency is an important platform to acquire physical examination skills including pubertal assessment. Objective An educational intervention for teaching pubertal assessment was piloted on pediatric residents at our institution. Methods The intervention comprised of interactive lecture series, ID badge size Tanner stage cards and Tanner posters placed in residents' continuity clinics. Pre-intervention, post-intervention and 3 months post-intervention surveys for participating trainees were administered to determine the effectiveness of the intervention. Attitudes, practices, knowledge scores, and barriers to Tanner staging conduct were analyzed. Results Forty-three residents participated in the intervention. Knowledge scores of PGY1 (5.95 ± 1.6 vs. 7.47 ± 1.4, p < 0.01) improved right after the intervention, as did self-reported clinical practices of all trainees 3 months post- intervention with regards to conducting external genital examination and performing pubertal assessment. Confidence levels of pediatric trainees in conducting pubertal assessment and comfort levels in assessing the need for endocrine referral based on abnormal Tanner staging improved after the intervention, although the effect was not statistically significant. Conclusion Our intervention is a worthwhile technique for teaching pubertal assessment to residents as it is simple to conduct, easily reproducible, provides baseline knowledge needed for recognition of normal pubertal development and puberty related conditions, and instills confidence in residents.

  5. Racial disparities in pubertal development.

    Science.gov (United States)

    Ramnitz, Mary Scott; Lodish, Maya B

    2013-09-01

    The question of whether or not children, particularly girls, are entering puberty earlier than they did in the past has been a concern in both the medical community and the general population. A secular trend analysis of the current data on pubertal timing in boys and girls is limited by variations in the study design, the population assessed, and the methods used to determine pubertal development. These differences present a challenge when interpreting the available data, especially when comparing multiple studies. The influence of race on pubertal timing and development had not been assessed before the 1970s. The purpose of this article is to review the reported variations in pubertal timing among different racial/ethnic groups. Data suggest African American girls enter puberty earlier and reach menarche earlier than Caucasian and Hispanic girls. In addition, the trend toward earlier timing of puberty seems to be occurring faster in African American girls compared with Caucasian girls over the past 25 years. While the mechanism and understanding of the cause of racial disparities in pubertal development remain to be discerned, genetic and/or environmental factors may play a role and require further investigation.

  6. Transitions in body and behavior: a meta-analytic study on the relationship between pubertal development and adolescent sexual behavior.

    Science.gov (United States)

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

    2015-06-01

    The present meta-analysis studies the relations of pubertal timing and status with sexual behavior and sexual risk behavior among youth aged 10.5-22.4 years. We included biological sex, age, and ethnicity as potential moderators. Four databases were searched for studies (published between 1980 and 2012) on the relation between pubertal timing or status and sexual behavior. The outcomes were (1) sexual intercourse; (2) combined sexual behavior; and (3) risky sexual behavior. Earlier pubertal timing or more advanced pubertal status was related to earlier and more sexual behavior, and earlier pubertal timing was related to more risky sexual behavior. Further, the links between (1) pubertal status and combined sexual behavior and (2) pubertal timing and sexual intercourse status, combined sexual behavior, and risky sexual behavior were stronger for girls than boys. Most links between pubertal status, timing, and sexual behavior and sexual risk behavior were stronger for younger adolescents. Moderation by ethnicity did not yield consistent results. There was significant variation in results among studies that was not fully explained by differences in biological sex, age, and ethnicity. Future research is needed to identify moderators that explain the variation in effects and to design sexual health interventions for young adolescents. Copyright © 2015 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

  7. Sex Variations in Youth Anxiety Symptoms: Effects of Pubertal Development and Gender Role Orientation

    Science.gov (United States)

    Carter, Rona; Silverman, Wendy K.; Jaccard, James

    2011-01-01

    This study evaluated whether pubertal development and gender role orientation (i.e., masculinity and femininity) can partially explain sex variations in youth anxiety symptoms among clinic-referred anxious youth (N = 175; ages 9-13 years; 74% Hispanic; 48% female). Using youth and parent ratings of youth anxiety symptoms, structural equation…

  8. Sex Variations in Youth Anxiety Symptoms: Effects of Pubertal Development and Gender Role Orientation

    Science.gov (United States)

    Carter, Rona; Silverman, Wendy K.; Jaccard, James

    2011-01-01

    This study evaluated whether pubertal development and gender role orientation (i.e., masculinity and femininity) can partially explain sex variations in youth anxiety symptoms among clinic-referred anxious youth (N = 175; ages 9-13 years; 74% Hispanic; 48% female). Using youth and parent ratings of youth anxiety symptoms, structural equation…

  9. Effect of high and low antral follicle count in pubertal beef heifers on IVF

    Science.gov (United States)

    Pubertal heifers can be classified between those with high (n = 25) or low (n = 15) antral follicle counts (AFC). The objective of this study was to determine oocyte development and maturation (e.g. fertility) in an IVF system for high- and low-AFC heifers. From a pool of 120 heifers, 10 high- and 1...

  10. Effect of pubertal development and physical activity on plasma ghrelin concentration in boys.

    Science.gov (United States)

    Jürimäe, J; Cicchella, A; Tillmann, V; Lätt, E; Haljaste, K; Purge, P; Pomerants, T; Jürimäe, T

    2009-01-01

    The aim of the present study was to assess the influence of regular physical activity on plasma ghrelin concentration in pre-pubertal and pubertal boys. In addition, the impact of ghrelin concentration on bone mineral density (BMD) was examined. In total, 56 healthy schoolboys aged between 10 and 16 yr were divided into the swimming (no.=28) and the control (no.=28) groups. The subjects were matched by age and body mass index (BMI), generating 9 matched pairs in pubertal group I (Tanner stage 1), 11 pairs in group II (Tanner stages 2 and 3), and 8 pairs in group III (Tanner stages 4 and 5). Swimmers in pubertal groups II and III had significantly (both pghrelin levels than the controls (group II: 1126.8+/-406.0 vs 868.3+/-411.2 pg/ml; group III: 1105.5+/-337.5 vs 850.8+/-306.0 pg/ml, respectively), whereas no difference was seen in the pubertal group I (1230.8+/-386.0 vs 1272.7+/-424.4 pg/ml). Ghrelin was the most important hormonal determinant for total BMD and lumbar apparent volumetric BMD (BMAD) (R2=27.2% and R2=19.8%, respectively) in swimmers, whereas in control boys, plasma IGF-I was the most important hormonal predictor accounting for 41.8% of the variability of total BMD and 20.4% of the variability of lumbar BMAD. In conclusion, ghrelin concentration decreased during puberty in physically inactive boys, while in regularly physically active boys it remained relatively unchanged. Ghrelin appears to be an important hormonal predictor for BMD in physically active boys, while BMD is mostly determined by IGF-I in physically inactive boys.

  11. Elite athletes and pubertal delay.

    Science.gov (United States)

    Kapczuk, Karina

    2017-10-01

    Intensive physical training and participation in competitive sports during childhood and early adolescence may affect athletes' pubertal development. On the other hand, pubertal timing, early or late, may impact on an athlete selection for a particular sport. Genetic predisposition, training load, nutritional status and psychological stress determine athletes' pubertal timing. Athletes that practice esthetic sports, especially gymnasts, are predisposed to a delay in pubertal development. The growing evidence indicates that energy deficiency, not a systemic training per se, plays a crucial role in the pathogenesis of functional hypothalamic hypogonadism in female athletes. Metabolic and psychologic stress activate hypothalamic-pituitary-adrenal axis and suppress hypothalamic-pituitary-ovarian axis. Female athletes who do not begin secondary sexual development by the age of 14 or menstruation by the age of 16 warrant a comprehensive evaluation and a targeted treatment. Somatic growth and sexual maturation of elite female athletes are largely sport-specific since each sport favors a particular somatotype and requires a specific training. Chronic negative energy balance resulting from a systemic physical training and inadequate energy intake may delay pubertal development in elite athletes. Youth athletes, especially those engaged in competitive sports that emphasize prepubertal or lean appearance, are at risk of developing relative energy deficiency in sport associated with disordered eating or eating disorders. Management strategies should address the complex conditions underlying functional hypothalamic hypogonadism.

  12. Effectiveness of vitamin E as treatment of primary dysmenorrhea in pubertal adolescents

    Directory of Open Access Journals (Sweden)

    Wagito

    2011-01-01

    Full Text Available Background Primary dysmenorrhea is a common complaint among adolescents. Absenteeism from work and school are associated with the severity of symptoms. Vitamin E is an alternative treatment for primary dysmenorrhea. Objective To evaluate the effectiveness of vitamin E as a treatment of primary dysmenorrhea. Methods We conducted a randomized, double-blind, controlled trial from August to October 2009. We included female adolescents with primary dysmenorrhea in this study. Subjects were divided into 2 groups by simple randomization. Each group received either 200 units of vitamin E or a placebo twice daily, beginning two days before menstruation and continuing until the third day of menstruation. Treatment was repeated for three menstrual cycles. Subjects recorded the severity and duration of pain in a daily diary. Data was analyzed using Chi-square, Mann-Whitney U-test, and independent t-test. Results One hundred-sixteen primary dysmenorrhea subjects enrolled in our study. By simple randomization, they were divided into two groups of 58 subjects each. There were no statistically significant differences between the two groups in the severity and duration of pain before the start of treatment and after 1 month of treatment. After treatment for 2 months and 3 months, there were statistically significant differences in pain severity (P=0.013, 95%CI -0.54 to -0.11; and P=0.0001, 95%CI -0.67 to -0.26, respectively and pain duration (P=0.025, 95%CI -0.65 to -0.07 and P=0.007, 95%CI -0.75 to -0.12, respectively between the 2 groups. Conclusion Vitamin E was effective in treatment of primary dysmenorrhea in pubertal adolescents after 2 and 3 months of treatment. [Paediatr Indones. 2011;51:41-6].

  13. Effect of Leaked Radiation from Microwave Oven on Bone Marrow of Male Rats in Pre and Post Pubertal Stage

    Directory of Open Access Journals (Sweden)

    G Jelodar

    2011-01-01

    Full Text Available Introduction: Increasing hematological diseases along with increased use of microwaves in different systems proposed possible correlation between them. Age of exposure to wave is also an important factor. This study was conducted to evaluate the effect of radiation leakaged from microwave oven on hemopoitic bone marrow cells at pre and post pubertal. Methods: Fourteen male mature (2 months old and 14 male immature rats(one month old were randomly divided in to four groups (control and test. Test groups were exposed, three times a day each time 30 min for 60 days, to microwaves produced by microwave oven. After sixty days, animals were sacrified and bone marrow samples were collected from femural bones. Percent of variose cells type and their morphology were evaluated in 500 cells of each smear. Results: exposure to microwave did not exert visible morphological alteration. In the immature experimental group significant decrease in percent of basophilic rubricyte, polychromatic rubricyte, meta rubricyte and all the erythroid cell types observed(P<0.05, whereas, meta myelocyte, notrophilic band, total myeloid cell types and prolifrative cells, other cell types and the myeloid/erythroid ratio significantly increased(P<0.05. In the mature group, however, a significant decrease in percent of meta rubricyte and myelocyte cells observed(P<0.05, although prolifrative cells and all other cell types were significantly increasing in this group. Conclusion: In conclusion, the radiation leaked from microwave oven in the experimental conditions had no effect on the morphology of hemopoitic bone marrow cells, though the number of these cells was altered especially in immature group.

  14. 青春发动时相提前与女生攻击行为的关联性分析%The correlation of the early pubertal timing and aggressive behavior of girls

    Institute of Scientific and Technical Information of China (English)

    俞荷俊; 周英; 顾璇; 朋文佳; 姚荣英

    2014-01-01

    higher than that in middle school girls(P <0. 05). The early pubertal timing was positively related to aggressive behavior(P < 0. 01),and negatively related to self-esteem and parent-child attachment(P < 0. 05 and P <0. 01). The self-esteem and parent-child attachment played partly mediator effects between early pubertal timing and aggressive behavior,the effects of which were 33. 87% and 25. 98%, respectively. The early pubertal timing, self-esteem and parent-child attachment played directly effects on aggressive behavior,and the early pubertal timing played indirectly effects on aggressive behavior by self-esteem and parent-child attachment. Conclusions:For preventing the aggressive behavior of middle school girls,correct guiding, grasping self-esteem and impoving parent-child attachment can relieve and reduce the aggressive behavior of middle school girls with the early pubertal timing.

  15. Effect of Aegle marmelos and Murraya koenigii in treatment of delayed pubertal buffaloes heifers

    Directory of Open Access Journals (Sweden)

    Mohan M. Baitule

    2016-12-01

    . koenigii alone, were found effective in fertility improvement in delayed pubertal buffalo heifers by increasing ovulation and conception rate.

  16. NMR-based metabolomic profiling of overweight adolescents – an elucidation of the effects of inter-/intra-individual differences, gender, pubertal development and physical activity

    DEFF Research Database (Denmark)

    Zheng, Hong; Yde, Christian Clement; Arnberg, Karina;

    2014-01-01

    The plasma and urine metabolome of 192 overweight 12-15-year-old adolescents (BMI of 25.4 ± 2.3 kg/m(2)) were examined in order to elucidate gender, pubertal development measured as Tanner stage, physical activity measured as number of steps taken daily, and intra-/interindividual differences...... in the metabolome are being commenced already in childhood. The relationship between Tanner stage and the metabolome showed that pubertal development stage was positively related to urinary creatinine excretion and negatively related to urinary citrate content. No relations between physical activity...... and the metabolome could be identified. The present study for the first time provides comprehensive information about associations between the metabolome and gender, pubertal development, and physical activity in overweight adolescents, which is an important subject group to approach in the prevention of obesity...

  17. Forty years trends in timing of pubertal growth spurt in 157,000 Danish school children

    DEFF Research Database (Denmark)

    Aksglæde, Lise; Olsen, Lina Wøhlk; Sørensen, Thorkild I.A.;

    2008-01-01

    BACKGROUND: Entering puberty is an important milestone in reproductive life and secular changes in the timing of puberty may be an important indicator of the general reproductive health in a population. Too early puberty is associated with several psychosocial and health problems. The aim of our...... a secular trend towards earlier sexual maturation of Danish children born between 1930 and 1969. Only minor changes were observed in duration of puberty assessed by the difference in ages at OGS and PHV Udgivelsesdato: 2008...

  18. The effects on steroidogenesis and histopathology of adult male Japanese quails (Coturnix coturnix japonica) testis following pre-pubertal exposure to di(n-butyl) phthalate (DBP).

    Science.gov (United States)

    Bello, Umar M; Madekurozwa, Mary-Catherine; Groenewald, Herman B; Aire, Tom A; Arukwe, Augustine

    2014-11-01

    In the present study, we have investigated the effects of 30-day dietary (pre-pubertal) exposure to different doses (0 (control), 1, 10, 50, 200 and 400 mg/kg bodyweight/day) of di(n-butyl) phthalate (DBP) on Leydig cells of adult male Japanese quails by quantifying the transcript levels for P450 side-chain cleavage (p450scc), P450c17 (CYP17), and 3β- and 17β-hydroxysteroid dehydrogenase (hsd) using quantitative (real-time) polymerase chain reaction (qRT-PCR). In addition, the plasma testosterone levels were analysed using radioimmunoassay (RIA) and testis was examined for evidence of gross pathology and histopathology. Our data showed that pre-pubertal exposure to DBP produced alterations in testicular architecture as evident by poorly developed or mis-shaped testis, and altered spermatogenesis due to tubular degeneration and atrophy of seminiferous tubules especially in the high DBP dose (200 and 400 mg/kg) treated groups. In addition, DBP altered several key enzymes involved in testicular steroidogenesis pathways in an apparent dose-dependent manner. For example, biphasic effects of DBP were observed for P450scc and 3β-hsd mRNA, that were generally increasing at low dose 10 mg/kg, and thereafter, an apparent dose-dependent decrease between 50 and 400mg/kg. The steroidogenic acute regulatory (StAR) protein was at the lowest detectable limits and therefore not quantifiable. These effects did not parallel the non-significant changes observed for plasma testosterone levels. The present data is consistent with previous reports showing that DBP modulates Leydig cell steroidogenesis in several species, with a potential negative effect on reproduction in those avian species that are vulnerable to endocrine disrupting chemicals.

  19. Adolescents' Increasing Stress Response to Social Evaluation: Pubertal Effects on Cortisol and Alpha-Amylase during Public Speaking

    Science.gov (United States)

    van den Bos, Esther; de Rooij, Mark; Miers, Anne C.; Bokhorst, Caroline L.; Westenberg, P. Michiel

    2014-01-01

    Stress responses to social evaluation are thought to increase during adolescence, which may be due to pubertal maturation. However, empirical evidence is scarce. This study is the first to investigate the relation between pubertal development and biological responses to a social-evaluative stressor longitudinally. Participants performed the Leiden…

  20. Adolescents' Increasing Stress Response to Social Evaluation: Pubertal Effects on Cortisol and Alpha-Amylase during Public Speaking

    Science.gov (United States)

    van den Bos, Esther; de Rooij, Mark; Miers, Anne C.; Bokhorst, Caroline L.; Westenberg, P. Michiel

    2014-01-01

    Stress responses to social evaluation are thought to increase during adolescence, which may be due to pubertal maturation. However, empirical evidence is scarce. This study is the first to investigate the relation between pubertal development and biological responses to a social-evaluative stressor longitudinally. Participants performed the Leiden…

  1. Pubertal development in Danish children

    DEFF Research Database (Denmark)

    Juul, A; Teilmann, G; Scheike, Thomas Harder

    2006-01-01

    differences between USA and Denmark, as well as to look for possible secular trends in pubertal development. Healthy Caucasian children from public schools in Denmark participated in the study which was carried out in 1991-1993. A total number of 826 boys and 1,100 girls (aged 6.0-19.9 years) were included......Two recent epidemiological studies (PROS and NHANES III) from the USA noted earlier sexual maturation in girls, leading to increased attention internationally to the age at onset of puberty. We studied the timing of puberty in a large cohort of healthy Danish children in order to evaluate......, and pubertal stages were assessed by clinical examination according to methods of Tanner. In boys testicular volume was determined using an orchidometer. We found that age at breast development 2 (B2) was 10.88 years, and mean menarcheal age was 13.42 years. Girls with body mass index (BMI) above the median...

  2. The long-term effects of the herbicide atrazine on the dopaminergic system following exposure during pubertal development.

    Science.gov (United States)

    Li, Yanshu; Sun, Yan; Yang, Junwei; Wu, Yanping; Yu, Jia; Li, Baixiang

    2014-03-15

    Atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) is used worldwide as a herbicide, and its presence in the environment has resulted in documented human exposure. Atrazine has been shown to cause dopaminergic neurotoxicity. The juvenile period is particularly vulnerable to environmental agents, but only few studies have investigated the long-term effects of atrazine following exposure during the pubertal development. Therefore, we evaluated the effects of a 41-day exposure to atrazine on the dopaminergic system in rats. Sprague-Dawley rats were treated orally with atrazine at 25 or 50mg/kg bw, daily from postnatal day 22 to 62. The content of dopamine (DA) was examined in striatum samples by HPLC-FL, and the mRNA and protein expression of tyrosine hydroxylase (TH), orphan nuclear hormone (Nurr1), dopamine transporter (DAT) and vesicular monoaminetransporter 2 (VMAT2) were examined in samples of the ventral mid-brain by use of fluorescence PCR and Western-blot analysis when the rats reached the age of one year. Exposure of juvenile rats to the high dose of atrazine led to reduced levels of DA and mRNA of Nurr1 in one-year-old animals. This study shows that the long-term adverse effects of atrazine on the dopaminergic system have a special relevance after juvenile exposure.

  3. Different effects on bone strength and cell differentiation in pre pubertal caloric restriction versus hypothalamic suppression.

    Science.gov (United States)

    Joshi, R N; Safadi, F F; Barbe, M F; Del Carpio-Cano, Fe; Popoff, S N; Yingling, V R

    2011-10-01

    Hypothalamic amenorrhea and energy restriction during puberty affect peak bone mass accrual. One hypothesis suggests energy restriction alters hypothalamic function resulting in suppressed estradiol levels leading to bone loss. However, both positive and negative results have been reported regarding energy restriction and bone strength. Therefore, the purpose of this study was to investigate energy restriction and hypothalamic suppression during pubertal onset on bone mechanical strength and the osteogenic capacity of bone marrow-derived cells in two models: female rats treated with gonadotropin releasing hormone antagonists (GnRH-a) or 30% energy restriction. At 23 days of age, female Sprague Dawley rats were assigned to three groups: control group (C, n=10), GnRH-a group (n=10), and Energy Restriction (ER, n=12) group. GnRH-a animals received daily injections for 27 days. The animals in the ER group received 70% of the control animals' intake. After sacrifice (50 days of age), body weight, uterine and muscle weights were measured. Bone marrow-derived stromal cells were cultured and assayed for proliferation and differentiation into osteoblasts. Outcome measures included bone strength, bone histomorphometry and architecture, serum IGF-1 and osteocalcin. GnRH-a suppressed uterine weight, decreased osteoblast proliferation, bone strength, trabecular bone volume and architecture compared to control. Elevated serum IGF-1 and osteocalcin levels and body weight were found. The ER model had an increase in osteoblast proliferation compared to the GnRH-a group, similar bone strength relative to body weight and increased trabecular bone volume in the lumbar spine compared to control. The ER animals were smaller but had developed bone strength sufficient for their size. In contrast, suppressed estradiol via hypothalamic suppression resulted in bone strength deficits and trabecular bone volume loss. In summary, our results support the hypothesis that during periods of

  4. Effect of insulin supplementation on in vitro maturation of pre-antral follicles from adult and pre-pubertal mice.

    Science.gov (United States)

    Nath, Amar; Hakim, Bilal Ahmad; Rajender, Singh; Singh, Kavita; Sachdev, Monika; Konwar, Rituraj

    2016-05-01

    This study was aimed to determine the impact of insulin concentrations on in vitro pre-antral follicle growth, survival, antrum formation rate, and retrieval of mature oocytes in mice. Mice pre-antral follicle growth were recorded on days 2, 4, 6, 8, 10, and 12 in α-modified essential media (α-MEM) supplemented with insulin concentrations of 6, 8, and 10 μg/ml along with 10% FBS, 100 mIU/ml follicle stimulating hormone, 10 mIU/ml luteinizing hormone, 100 μg/ml penicillin, and 50 μg/ml streptomycin. After 12 d of growth in vitro, follicles were allowed to mature for 16-18 h in α-MEM supplemented with 1.5 IU/ml human chorionic gonadotrophin (hCG) and 5 ng/ml epidermal growth factor (EGF). The initial diameter (54.86 ± 2.5 μm) of mice oocyte progressively increased in all the three insulin concentration groups and attained a maximum size on day 12 (71.90 ± 2.8 μm). Supplementation with higher concentrations of insulin (both 8 and 10 μg/ml) significantly enhanced antrum formation without effecting the oocyte diameter and percent retrieval of mature oocyte in all the three concentration groups. Both in vitro cultured as well as in vivo collected follicles and oocytes showed similar localization and expression of oocyte maturation markers SAS1B and GDF9. Insulin concentration of 8 μg/ml was found to be optimal for in vitro follicle culture of adult mice (42-49 d). Optimized follicle culture conditions were also assessed successfully with pre-pubertal mice (12-14 d); however, adult mice showed higher follicle survival, antrum formation, and more mature oocytes production in comparison to pre-pubertal mice.

  5. Hormonal determinants of pubertal growth.

    NARCIS (Netherlands)

    Delamarre-van Waal, H.A.; Coeverden, S.C. van; Rotteveel, J.J.

    2001-01-01

    Pubertal growth results from increased sex steroid and growth hormone (GH) secretion. Estrogens appear to play an important role in the regulation of pubertal growth in both girls and boys. In girls, however, estrogens cannot be the only sex steroids responsible for pubertal growth, as exogenous est

  6. Nutrition and pubertal development

    Directory of Open Access Journals (Sweden)

    Ashraf Soliman

    2014-01-01

    Full Text Available Nutrition is one of the most important factors affecting pubertal development. Puberty entails a progressive nonlinear process starting from prepubescent to full sexual maturity through the interaction and cooperation of biological, physical, and psychological changes. Consuming an adequate and balanced healthy diet during all phases of growth (infancy, childhood and puberty appears necessary both for proper growth and normal pubertal development. Girls begin puberty at an earlier age compared to past decades. Excessive eating of many processed, high-fat foods, may be the cause of this phenomenon. Overweight or obese children are more likely to enter puberty early. Some evidence suggests that obesity can accelerate the onset of puberty in girls and may delay the onset of puberty in boys. Moreover, the progression of puberty is affected by nutrition. On the other hand, puberty triggers a growth spurt, which increases nutritional needs including macro and micronutrients. Increased caloric, protein, iron, calcium, zinc and folate needs have to be provided during this critical period of rapid growth. Severe primary or secondary malnutrition also can delay the onset and progression of puberty. The higher incidence of anorexia nervosa and bulimia in adolescents imposes a nutritional risk on pubertal development. Moreover, many environmental endocrine disruptors (EDs have been identified that can significantly impair the normal course of puberty. This mini-review sums up some important findings in this important complex that link nutrition and pubertal development.

  7. Effect of high and low antral follicle count in pubertal beef heifers on in vitro fertilization (IVF)

    Science.gov (United States)

    Pubertal heifers can be classified between those with high (= 25) and low (= 15) antral follicle counts (AFC). The objective of this study was to determine oocyte development and maturation (e.g., fertility) in an in vitro fertilization (IVF) system for high and low AFC heifers. From a pool of 120...

  8. Season of birth is associated with birth weight, pubertal timing, adult body size and educational attainment: a UK Biobank study

    Directory of Open Access Journals (Sweden)

    Felix R. Day

    2015-10-01

    Full Text Available Season of birth, a marker of in utero vitamin D exposure, has been associated with a wide range of health outcomes. Using a dataset of ∼450,000 participants from the UK Biobank study, we aimed to assess the impact of this seasonality on birth weight, age at menarche, adult height and body mass index (BMI. Birth weight, age at menarche and height, but not BMI, were highly significantly associated with season of birth. Individuals born in summer (June–July–August had higher mean birth weight (P = 8 × 10−10, later pubertal development (P = 1.1 × 10−45 and taller adult height (P = 6.5 × 10−9 compared to those born in all other seasons. Concordantly, those born in winter (December–January–February showed directionally opposite differences in these outcomes. A secondary comparison of the extreme differences between months revealed higher odds ratios [95% confidence intervals (CI] for low birth weight in February vs. September (1.23 [1.15–1.32], P = 4.4 × 10−10, for early puberty in September vs. July (1.22 [1.16–1.28], P = 7.3 × 10−15 and for short stature in December vs. June (1.09 [1.03–1.17], P = 0.006. The above associations were also seen with total hours of sunshine during the second trimester, but not during the first three months after birth. Additional associations were observed with educational attainment; individuals born in autumn vs. summer were more likely to continue in education post age 16 years (P = 1.1 × 10−91 or attain a degree-level qualification (P = 4 × 10−7. However, unlike other outcomes, an abrupt difference was seen between those born in August vs. September, which flank the start of the school year. Our findings provide support for the ‘fetal programming’ hypothesis, refining and extending the impact that season of birth has on childhood growth and development. Whilst other mechanisms may contribute to these associations, these findings are consistent with a possible role of in utero

  9. Effects of 2,4-dichlorophenoxyacetic acid on the ventral prostate of rats during the peri-pubertal, pubertal and adult stage.

    Science.gov (United States)

    Pochettino, Arístides A; Hapon, María Belén; Biolatto, Silvana M; Madariaga, María José; Jahn, Graciela A; Konjuh, Cintia N

    2016-10-01

    The herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) is used on a wide variety of terrestrial and aquatic broadleaf weeds. 2,4-D has been shown to produce a wide range of adverse effects on animal and human health. The aim of the current study was to evaluate the effects of pre- and postnatal exposure to 2,4-D on rat ventral prostate (VP). Pregnant rats were exposed daily to oral doses of 70 mg/kg/day of 2,4-D from 16 days of gestation up to 23 days after delivery. Then, the treated groups (n = 8) were fed with a 2,4-D added diet until sacrificed by decapitation on postnatal day (PND) 45, 60, or 90. Morphometric studies were performed and androgen receptor (AR) protein levels in the VP were determined. AR, insulin-like growth factor-I (IGF-1) and insulin-like growth factor-I receptor (IGF-1R) mRNA expression in the VP along with testosterone (T), dihydroxytestosterone (DHT), growth hormone (GH) and IGF-1 serum levels were also determined to ascertain whether these parameters were differentially affected. Results of this study showed that 2,4-D exposure during gestation and until adulthood altered development of the prostate gland in male rats, delaying it at early ages while increasing its size in adults, indicate that 2,4-D could behave as endocrine disruptors (EDs).

  10. Male pubertal development: are endocrine-disrupting compounds shifting the norms?

    Science.gov (United States)

    Zawatski, William; Lee, Mary M

    2013-01-01

    Endocrine-disrupting compounds (EDCs) are synthetic or natural compounds that interfere with endogenous endocrine action. The frequent use of chemicals with endocrine active properties in household products and contamination of soil, water, and food sources by persistent chemical pollutants result in ubiquitous exposures. Wildlife observations and animal toxicological studies reveal adverse effects of EDCs on reproductive health. In humans, a growing number of epidemiological studies report an association with altered pubertal timing and progression. While these data are primarily reported in females, this review will focus on the small number of studies performed in males that report an association of polychlorinated biphenyls with earlier sexual maturity rating and confirm subtle effects of lead, dioxins, and endosulfan on delaying pubertal onset and progression in boys. Recent studies have also demonstrated that EDC exposure may affect pubertal testosterone production without having a noticeable effect on sexual maturity rating. A limitation to understand the effects of EDCs in humans is the potential for confounding due to the long temporal lag from early-life exposures to adult outcomes. The complex interplay of multiple environmental exposures over time also complicates the interpretation of human studies. These studies have identified critical windows of vulnerability during development when exposures to EDCs alter critical pathways and affect postnatal reproductive health. Contemporaneous exposures can also disrupt the hypothalamic-pituitary-gonadal axis. This paper will review the normal process of puberty in males and summarize human data that suggest potential perturbations in pubertal onset and tempo with early-life exposures to EDCs.

  11. Effects of oral intoxication by lead acetate on pituitary-testicular axis in the pubertal rat

    Directory of Open Access Journals (Sweden)

    Hachfi Lamia

    2008-12-01

    Full Text Available

    Background: The aim of this work is to study the effects of lead on pituitary-testicular axis. It is about a direct toxicity on testicular cells or an indirect toxicity via abnormalities of the hypothalamic-pituitary axis?

    Methods: Forty male rats were divided equitably into four groups. One of these groups received tap water containing 0.3% lead acetate for one month. A second group was assigned to the same protocol but the intoxication was conducted for two months. The third and the fourth groups were used as reference. At the end of the experiment, the rats were anaesthetized and blood was collected for the proportioning of the FSH, the LH, testosterone and lead. The testes and epididymides were removed quickly and weighed. For the determination of testosterone in testicular fluids, a cruciate incision was made in the tunica albuginea of each right testis and centrifuged at 54xg for the extraction of interstitial fluid. Thereafter, the seminiferous tubules were extruded and centrifuged at 6000xg to collect seminiferous tubule fluid. The left testis of each animal was cut in two halves, one half was used for the histological examination and the other was suitably treated for the determination of the lead concentration. The epididymides were homogenized in solution containing Triton X-100 and spermatozoa were counted using Malessez cells. The plasma FSH and LH were determined by RIA using reagents from a commercial kit (BioInternational, France, while testosterone was determined by electrochemiluminescence (Elecsys, rochediagnostics. The lead concentration in blood and Tissues was measured by flameless atomic absorption spectrophotometry with the Zeeman effect background (Hitachi Z- 9000.

    Results: In the rats poisoned for one month, no notable effect was noted in spite of a blood lead concentration of 0.721 μg/ml. On the contrary, in animals exposed to lead acetate for two

  12. Pubertal development in Danish children

    DEFF Research Database (Denmark)

    Juul, A; Teilmann, G; Scheike, Thomas Harder

    2006-01-01

    Two recent epidemiological studies (PROS and NHANES III) from the USA noted earlier sexual maturation in girls, leading to increased attention internationally to the age at onset of puberty. We studied the timing of puberty in a large cohort of healthy Danish children in order to evaluate differe...... genetic polymorphisms, nutrition, physical activity or endocrine disrupting chemicals must therefore also be considered. Therefore, we believe it is crucial to monitor the pubertal development closely in Denmark in the coming decades.......Two recent epidemiological studies (PROS and NHANES III) from the USA noted earlier sexual maturation in girls, leading to increased attention internationally to the age at onset of puberty. We studied the timing of puberty in a large cohort of healthy Danish children in order to evaluate...

  13. 中学生攻击行为与自感青春发动时相及学校因素的关系%Association of aggressive behavior with perceived pubertal timing and school factors in middle school students

    Institute of Scientific and Technical Information of China (English)

    俞荷俊; 乔淮燕; 张戎; 周英; 姚荣英

    2013-01-01

    目的 按不同性别探索中学生攻击行为与自感青春发动时相及学校因素的关系.方法 对2 791名中学生进行青春发育状况、攻击行为的问卷调查.结果 不同自感青春发动时相中学生攻击行为得分差异有统计学意义(F=14.676,P<0.05);不同学校风气、师生关系、同学关系、好朋友数中学生攻击行为得分差异有统计学意义(P<0.05);多重线性回归显示,男生攻击行为的影响因素为学校风气、自感青春发动时相、师生关系(β分别为-0.134、-0.114、-0.098,P<0.05);女生攻击行为的影响因素为师生关系、好朋友数、学校风气、自感青春发动时相(β分别为-0.120、-0.103、-0.102、-0.089,P<0.05).结论 自感青春发动时相及学校因素对中学生攻击行为的影响存在性别差异,在预防上应将时相偏离(提前或推迟)的男生,时相提前的女生列入重点对象.%Objective To explore the relationship between perceived pubertal timing together with school factors and the aggressive behavior in middle school students with different genders.Methods A total of 2 791 middle school students were surveyed by a questionnaire for youth development status and aggressive behavior.Results The score of aggressive behavior was significantly different in middle school students with different perceived pubertal timing (F =14.676,P < 0.05).The score of aggressive behavior was significantly different in middle school students with different general mood of school,relationship between classmates and teachers and the number of close friends (P < 0.05).Multiple linear regression analysis indicated that the influencing factors of male students' aggressive behavior were general mood of school,perceived pubertal timing and the relationship with teachers (β =-0.134,-0.114,-0.098,respectively,P < 0.05).The influencing factors of female students' aggressive behavior were the relationship with teachers,the number of

  14. Pubertal pair-housing facilitates adult sexual behavior in male rats.

    Science.gov (United States)

    Molenda-Figueira, Heather A; Bell, Margaret R; De Lorme, Kayla C; Sisk, Cheryl L

    2017-01-01

    This study examined the effects of pubertal testosterone (T) and social housing manipulations on male sexual behavior in adult rats. Prepubertal rats were castrated at 21 days of age (P21) and implanted with either blank or T-releasing pellets. At the onset of puberty, P28, half the rats in each treatment group were either single- or pair-housed with a male of the same hormone condition through P56, at which time pellets were removed and all rats were single-housed. In adulthood (P84), all rats received T replacement and were tested for sexual behavior. Rats pair-housed during adolescence showed more sexual behavior and greater improvement of sexual performance over repeated tests than single-housed rats, regardless of pubertal T status. Pubertal T, however, did facilitate the frequency of anogenital investigation. Thus, in male rats, social interactions during adolescence are more important than exposure to pubertal T in enhancing adult sexual behavior. © 2016 Wiley Periodicals, Inc.

  15. Effects of Habitual Physical Activity and Fitness on Tibial Cortical Bone Mass, Structure and Mass Distribution in Pre-pubertal Boys and Girls: The Look Study.

    Science.gov (United States)

    Duckham, Rachel L; Rantalainen, Timo; Ducher, Gaele; Hill, Briony; Telford, Richard D; Telford, Rohan M; Daly, Robin M

    2016-07-01

    Targeted weight-bearing activities during the pre-pubertal years can improve cortical bone mass, structure and distribution, but less is known about the influence of habitual physical activity (PA) and fitness. This study examined the effects of contrasting habitual PA and fitness levels on cortical bone density, geometry and mass distribution in pre-pubertal children. Boys (n = 241) and girls (n = 245) aged 7-9 years had a pQCT scan to measure tibial mid-shaft total, cortical and medullary area, cortical thickness, density, polar strength strain index (SSIpolar) and the mass/density distribution through the bone cortex (radial distribution divided into endo-, mid- and pericortical regions) and around the centre of mass (polar distribution). Four contrasting PA and fitness groups (inactive-unfit, inactive-fit, active-unfit, active-fit) were generated based on daily step counts (pedometer, 7-days) and fitness levels (20-m shuttle test and vertical jump) for boys and girls separately. Active-fit boys had 7.3-7.7 % greater cortical area and thickness compared to inactive-unfit boys (P < 0.05), which was largely due to a 6.4-7.8 % (P < 0.05) greater cortical mass in the posterior-lateral, medial and posterior-medial 66 % tibial regions. Cortical area was not significantly different across PA-fitness categories in girls, but active-fit girls had 6.1 % (P < 0.05) greater SSIpolar compared to inactive-fit girls, which was likely due to their 6.7 % (P < 0.05) greater total bone area. There was also a small region-specific cortical mass benefit in the posterior-medial 66 % tibia cortex in active-fit girls. Higher levels of habitual PA-fitness were associated with small regional-specific gains in 66 % tibial cortical bone mass in pre-pubertal children, particularly boys.

  16. Age at pubertal onset and educational outcomes

    DEFF Research Database (Denmark)

    Essen, Emma von; Dreber, Anna; Ranehill, Eva

    2011-01-01

    Education has important short and long run implications for individual outcomes. In this paper we explore the association between age at pubertal onset and educational outcomes in a sample of Swedish girls. Previous research suggests that girls that mature earlier perform worse in school compared...... to girls that mature later. To test if this is also true among Swedish girls, we investigate the association between pubertal development and grades, educational aspirations and educational choice. We also investigate whether changes in risk attitudes, time preferences and priorities concerning school...... versus friends mediate this potential correlation. We confirm that earlier maturing girls have lower grades and lower educational aspirations, but find that they make educational choices similar to those of later maturing girls. Furthermore, we do not find that these differences in grades and aspirations...

  17. Update on statural growth and pubertal development in obese children

    Directory of Open Access Journals (Sweden)

    Chiara De Leonibus

    2012-12-01

    Full Text Available Childhood obesity is a growing and alarming problem, associated with several short-term and long-term metabolic and cardiovascular complications. In addition, it has also been suggested that excess adiposity during childhood influences growth and pubertal development. Several studies have shown that during pre-pubertal years, obese patients present higher growth velocity and that this pre-pubertal advantage tends to gradually decrease during puberty, leading to similar final heights between obese and non-obese children. Excess body weight might also influence pubertal onset, leading to earlier timing of puberty in girls. In addition, obese girls are at increased risk of hyperandrogenism and polycystic ovary syndrome. In boys, a clear evidence does not exist: some studies suggesting an earlier puberty associated with the obesity status, whereas other have found a delayed pubertal onset. Overall, the existing evidence of an association between obesity and modification of growth and pubertal patterns underlines a further reason for fighting the epidemics of childhood obesity.

  18. Age at voice break in Danish boys: effects of pre-pubertal body mass index and secular trend

    DEFF Research Database (Denmark)

    Juul, Anders; Magnusdottir, Steinunn; Scheike, Thomas

    2007-01-01

    in the boys choir and pre-pubertal body mass index (BMI)] by survival analysis techniques based on retrospective analyses of age at voice break in 463 Danish choir boys who were studied over a 10-year period. We found an overall median age at voice break of 14.0 [13.9-14.6] years, and a statistically...... significant downwards trend in age at voice break in the 10-year period (1994-2003) (log-rank test p = 0.0146). There was a statistically significant difference in age at voice break between boys in the different BMI quartiles in pre-puberty (p = 0.00822) with a tendency towards early voice break...... with increasing BMI standard deviation scores. Thus boys in the heaviest quartile at 8 years of age had an increased risk of early voice break (RR of 1.74 [1.14-2.65]) approximately 6 years later, compared with boys in the thinnest quartile. The earlier voice break seen during the 10-year observation period could...

  19. Effect of oral intake of dibutyl phthalate on reproductive parameters of Long Evans rats and pre-pubertal development of their offspring.

    Science.gov (United States)

    Salazar, Veronica; Castillo, Carmen; Ariznavarreta, Carmen; Campón, Rocío; Tresguerres, Jesús A F

    2004-12-01

    To investigate the influence of dibutyl phtalate (DBP) given in a soy-free rat chow on pre-pubertal development, 46 Long Evans female rats 2-month-old were divided into three experimental groups and fed three different chows: (1) control; (2) DP 0.61 g/kg chow (12 mg/kgrat/day); (3) DP 2.5 g/kg chow (50 mg/kg rat/day) for 2 months. While under this treatment, they were mated and their offspring studied. Litter size and female:male ratio were recorded. At 14 days of age 6, male pups of each group were sacrificed and testis and thymus were excised and weighed. Pups were weaned at 22 days of age and continued into three experimental groups according to diet. From day 22 onwards, vaginal opening, occurrence of first estrous, and pre-putial separation were recorded. The percent of pregnancies showed a marked decrease in group 3, while no difference was observed between groups 1 and 2. Sex prevalence and litter size were not affected by the different diets. Pup survival showed a decrease when mothers were fed diet 2, but it was similar in diets 1 and 3. Pup weights on day 2 showed an evident (P < 0.05) reduction in groups 2 and 3, the decrease being more marked (P < 0.001) in group 3. On day 6, pups of group 2 showed lower weights (P < 0.01) as compared with the other groups. Weight gain was significantly higher in pups of group 3. Eye opening was not affected by the different diets. Fourteen-day-old male pups' relative weight of thymus and testis showed a decrease in animals whose mothers had been fed diets 2 and 3. Vaginal opening and occurrence of first estrous showed an evident delay (P < 0.05; P < 0.01) in females fed diets 2 and 3. Significant differences (P < 0.001) in pre-putial separation were observed between treated and untreated groups. Offspring pre-pubertal development seems to be affected by oral intake of DBP by their mothers during pregnancy, the effects being more evident in the reproductive development of male pups.

  20. BMI percentile-for-age overestimates adiposity in early compared with late maturing pubertal children

    DEFF Research Database (Denmark)

    Sørensen, Kaspar; Juul, Anders

    2015-01-01

    .041) was found with early compared with late maturation, despite similar BIA-estimated body fat percentage (BIA-BF%). Neither BMI nor BIA-BF% differed for a given stage of maturation. BMI percentile-for-age and prevalence of overweight/obesity were higher in the early compared with late matured pubertal children......OBJECTIVE: Early pubertal timing is consistently associated with increased BMI percentile-for-age in pubertal girls, while data in boys are more ambiguous. However, higher BMI percentile-for-age may be a result of the earlier puberty per se rather than vice versa. The aim was to evaluate markers...... of adiposity in relation to pubertal timing and reproductive hormone levels in healthy pubertal boys and girls. STUDY DESIGN: Population-based cross-sectional study (The Copenhagen Puberty Study). Eight-hundred and two healthy Caucasian children and adolescents (486 girls) aged 8.5-16.5 years participated. BMI...

  1. Effects of biostimulation and nutritional supplementation on pubertal age and pregnancy rates of Nelore heifers (Bos indicus) in a tropical environment.

    Science.gov (United States)

    Oliveira, C M G; Oliveira Filho, B D; Gambarini, M L; Viu, M A O; Lopes, D T; Sousa, A P F

    2009-07-01

    To determine effects of biostimulation (BIO) and dietary supplementation (BIO+S) on pubertal age and pregnancy rates, Nelore heifers (n=392) were randomly assigned to one of four treatment groups (n=98/group). All animals were in tropical environmental conditions, in the middle-west region of Brazil, grazing in pastures of Brachiaria brizantha, cv. Marandu; Panicum Maximum, cv. Tanzânia and Brachiaria humidícula. The heifers of the BIO group were kept in the presence of bulls while being maintained on pasture; the animals in the BIO+S group were kept in the presence of bulls while being managed on pasture and were fed a diet with greater energy and protein content to produce 0.49 kg of BW gain/day; the animals in control group (the NBIO) were kept away from bulls and under pasture conditions; and the animals in the NBIO+S group were kept away from bulls, were maintained on pasture, and were fed the same diet as the BIO+S group. Heifers were bred at 22-23 months of age, and pregnancy diagnosis was made 45 days after the end of the breeding season. There were differences (Ppregnancy rates (Pdecreased age at the first breeding season, resulting in a significant reduction in age of first pregnancy in Nelore heifers kept under extensive management systems in a tropical environment.

  2. The Effect of Low Monotonic Doses of Zearalenone on Selected Reproductive Tissues in Pre-Pubertal Female Dogs--A Review.

    Science.gov (United States)

    Gajęcka, Magdalena; Zielonka, Łukasz; Gajęcki, Maciej

    2015-11-19

    The growing interest in toxic substances combined with advancements in biological sciences has shed a new light on the problem of mycotoxins contaminating feeds and foods. An interdisciplinary approach was developed by identifying dose-response relationships in key research concepts, including the low dose theory of estrogen-like compounds, hormesis, NOAEL dose, compensatory response and/or food tolerance, and effects of exposure to undesirable substances. The above considerations increased the researchers' interest in risk evaluation, namely: (i) clinical symptoms associated with long-term, daily exposure to low doses of a toxic compound; and (ii) dysfunctions at cellular or tissue level that do not produce clinical symptoms. Research advancements facilitate the extrapolation of results and promote the use of novel tools for evaluating the risk of exposure, for example exposure to zearalenone in pre-pubertal female dogs. The arguments presented in this paper suggest that low doses of zearalenone in commercial feeds stimulate metabolic processes and increase weight gains. Those processes are accompanied by lower proliferation rates in the ovaries, neoangiogenesis and vasodilation in the ovaries and the uterus, changes in the steroid hormone profile, and changes in the activity of hydroxysteroid dehydrogenases. All of the above changes result from exogenous hyperestrogenizm.

  3. The Examination of the Effectiveness of an Educational Intervention based on the Planned Behavior Theory on Improving Pubertal Health Behavior in Female High School Students

    Directory of Open Access Journals (Sweden)

    Farnaz Eslamimehr

    2017-09-01

    Full Text Available Background: Puberty is a period of psychological, physical, mental, emotional and social growth that stability and development of personality occurs in this period. This study aimed to determine the effect of planned behavior theory on improving pubertal health behavior in female first grade high school students. Materials and Methods:  A quasi-experimental intervention was conducted in female high school in Khamir city, Iran in 2015. One of the schools were randomly assigned to the control group and other to the experimental group. Using the formula sample, 60 students were selected from each school. Samples were evaluated in two stages through pre-test and two months later via post-test by administered questionnaire including questions about demographic characteristics and structures of planned behavior theory. The content of training was presented through lecture group discussion with teaching aids such as booklet and pamphlet. The collected data were analyzed using SPSS version 22. Results: The intervention group mean age at first menstrual period was 12.30 ± 0.84 years old and for control group was 12.25 ± 0.79 years old. The results showed that two months after the intervention, health behaviors, subjective norms, behavioral intention, perceived behavioral control, and attitude, were significantly higher than pre- intervention (P

  4. Transitions in Body and Behavior : A Meta-Analytic Study on the Relationship Between Pubertal Development and Adolescent Sexual Behavior

    OpenAIRE

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

    2015-01-01

    The present meta-analysis studies the relations of pubertal timing and status with sexual behavior and sexual risk behavior among youth aged 10.5-22.4 years. We included biological sex, age, and ethnicity as potential moderators. Four databases were searched for studies (published between 1980 and 2012) on the relation between pubertal timing or status and sexual behavior. The outcomes were (1) sexual intercourse; (2) combined sexual behavior; and (3) risky sexual behavior. Earlier pubertal t...

  5. Influence of Pubertal Timing to Adolescent Heterosexual Behaviors and Reproductive Health Information Seeking Practices%青春发动时相对于职校学生性行为及网络生殖健康信息获取的影响

    Institute of Scientific and Technical Information of China (English)

    张珊; 史慧静; 张越; 余春艳

    2011-01-01

    目的:分析青春发动时相对于职校学生性行为和网络生殖健康信息获取的影响.方法:在随机整群选取的1 846名中等职业技术学校学生中,问卷调查青春发育时间、异性间性行为、以及生殖健康信息获取经历.结果:青春发动时相提前男、女生的各种性行为自我报告率均显著高于适时组和延迟组.互联网是职校生寻求性生殖健康信息的重要来源之一,青春发动时相提前对于其网络性生殖健康信息寻求具有独立作用.结论:在开展有针对性的职校生性生殖健康教育中,尤其要关注和合理引导青春发动时相偏离正常的学生.%Objective: To investigate the influence of pubertal timing to vocational high school students' heterosexual behaviors as well as their practices of online seeking for reproductive health information.Methods: By using structural self-administered questionnaire, self-perceived pubertal timing, heterosexual behaviors, and perceived valuable and helpful ways of obtaining reproductive health information, as well as experiences of Internet surfing reproductive health information were obtained from a cluster-randomized sample of 1 864 vocational high school students in Shanghai.Results: Of various information sources of sex and reproductive health, Internet surfing was much more preferred and recognized by all respondents.In both males and females, self-reported rates of heterosexual behaviors in the earlier puberty group were significantly higher than those in the ordinary and delayed groups.Percentages of those vocational high school students, surfing online for sex and reproductive health knowledge were highest in earlier puberty group, followed by delayed group and ordinary group.The independent effect of pubertal timing on the sex and reproductive information seeking via Internet was existed even after controlling for age, sex, hours of internet use per day, selfperceived study achievement and averaged parents

  6. Pubertal development among girls with classical congenital adrenal hyperplasia initiated on treatment at different ages

    Directory of Open Access Journals (Sweden)

    Bindu Kulshreshtha

    2012-01-01

    Full Text Available Introduction: Children with congenital adrenal hyperplasia (CAH provide us an opportunity to study the clinical effects of androgen excess in humans. We studied the sequence of pubertal development in girls with congenital adrenal hyperplasia initiated on treatment at different ages, to assess the effects of androgen exposure on the Hypothalamic-Pituitary-Ovarian (HPO axis. Materials and Methods: Girls more than 18 years of age, with CAH, on follow-up at this hospital were the subjects for this study. Details of history, physical findings, laboratory evaluation, and medication were noted from their case records and verified from the patients and their / parents, in addition to assessment of their present health status. Result: We studied 24 patients of classical CAH (SW-2, SV-22, average age - 24.5 ± 6.6 years. All had varying degrees of genital ambiguity (Prader stage 3 (n = 13, Prader stage 2 (n = 10, Prader stage 1 (n = 1. Among them were13 girls, who were started on steroids after eight years of age. Girls who received treatment from infancy and early childhood had normal pubertal development (mean age at menarche 11.4 ± 1.7 years. Hirsutism was not a problem among them. Untreated children had progressive clitoral enlargement throughout childhood, developed pubic hair at around three to six years of age, and facial hair between nine and eleven years. Plasma testosterone ranged from 3 to 6 ng / ml prior to treatment. Six of the 13 untreated CAH girls had subtle breast development starting at ages 11 - 16 years and three had spontaneous infrequent vaginal bleeding starting at ages 11 - 17. Steroid supplementation initiated pubertal changes in older girls in two-to-six months′ time. Conclusion: There was a delay in HPO axis maturation (as evidenced by delayed pubertal development in the absence of treatment in girls with CAH. This could be corrected with steroid supplementation.

  7. Effect of Radiation Leakage of Microwave Oven on Rat Serum Testosterone at Pre and Post Pubertal Stage

    Directory of Open Access Journals (Sweden)

    Y Zare

    2008-01-01

    Full Text Available Introduction: Since discovery of high frequency waves, their biological effects have been in great attention. Increased male fertility problems proposed their possible relation to use of microwaves. Testes are of very active body tissues, which can be affected by these waves. Age of exposure may also be an important factor. Methods: This study was carried out to evaluated testosterone level in rats exposed to microwave radiation at pre and post puberty. For this study 18 adult (2 month old and 18 immature (1 month old male rats were selected and each group divided in two groups, control and test group. Test groups were exposed to 2450 MHZ microwaves produced by microwave oven (LG Brant, three times a day, 30 minute each time. Control groups were kept in laboratory at same temperature and light condition. After 60 days blood was collected by heart puncture and testosterone was measured in serum by RIA method. Mean testosterone levels were compared by T-test. Result: The results showed that in immature group testosterone has not changed significantly compare to control group; however in adult group this value was significantly decreased in test group in comparison with control (P<0.005. Conclusion: exposure to microwaves leakage of microwave oven decreased testosterone in adult male rats, which may be due to its direct effect on Leydig cells or indirectly through its effect on pituitary and hypothalamus.

  8. Dioxin Exposure and Age of Pubertal Onset among Russian Boys

    Science.gov (United States)

    Lee, Mary M.; Williams, Paige L.; Sergeyev, Oleg; Burns, Jane S.; Patterson, Donald G.; Turner, Wayman E.; Needham, Larry L.; Altshul, Larisa; Revich, Boris; Hauser, Russ

    2011-01-01

    Background: Animal data demonstrate associations of dioxin, furan, and polychlorinated biphenyl (PCB) exposures with altered male gonadal maturation. It is unclear whether these associations apply to human populations. Objectives: We investigated the association of dioxins, furans, PCBs, and corresponding toxic equivalent (TEQ) concentrations with pubertal onset among boys in a dioxin-contaminated region. Methods: Between 2003 and 2005, 499 boys 8–9 years of age were enrolled in a longitudinal study in Chapaevsk, Russia. Pubertal onset [stage 2 or higher for genitalia (G2+) or testicular volume (TV) > 3 mL] was assessed annually between ages 8 and 12 years. Serum levels at enrollment were analyzed by the Centers for Disease Control and Prevention, Atlanta, Georgia, USA. We used Cox proportional hazards models to assess age at pubertal onset as a function of exposure adjusted for potential confounders. We conducted sensitivity analyses excluding boys with pubertal onset at enrollment. Results: The median (range) total serum TEQ concentration was 21 (4–175) pg/g lipid, approximately three times higher than values in European children. At enrollment, boys were generally healthy and normal weight (mean body mass index, 15.9 kg/m2), with 30% having entered puberty by G2+ and 14% by TV criteria. Higher dioxin TEQs were associated with later pubertal onset by TV (hazard ratio = 0.68, 95% confidence interval, 0.49–0.95 for the highest compared with the lowest quartile). Similar associations were observed for 2,3,7,8-tetrachlorodibenzo-p-dioxin and dioxin concentrations for TV but not G2+. Results were robust to sensitivity analyses. Conclusions: Findings support an association of higher peripubertal serum dioxin TEQs and concentrations with later male pubertal onset reflected in delayed testicular maturation. PMID:21527364

  9. NMR-based metabolomic profiling of overweight adolescents – an elucidation of the effects of inter-/intra-individual differences, gender, pubertal development and physical activity

    DEFF Research Database (Denmark)

    Zheng, Hong; Yde, Christian Clement; Arnberg, Karina

    2014-01-01

    The plasma and urine metabolome of 192 overweight 12-15-year-old adolescents (BMI of 25.4 ± 2.3 kg/m(2)) were examined in order to elucidate gender, pubertal development measured as Tanner stage, physical activity measured as number of steps taken daily, and intra-/interindividual differences aff...

  10. The effects of long-term exposure to a 2450 MHz electromagnetic field on growth and pubertal development in female Wistar rats.

    Science.gov (United States)

    Sangun, Ozlem; Dundar, Bumin; Darici, Hakan; Comlekci, Selcuk; Doguc, Duygu Kumbul; Celik, Suheyla

    2015-03-01

    The aim of this study was to investigate the effects of a 2450 MHz electromagnetic field (EMF) (wireless internet frequency) on the growth and development of female Wistar rats. The study was conducted on three groups of rats. The prenatal and postnatal groups were exposed to EMF 1 h/day beginning from intrauterine and postnatal periods, respectively. The third group was the sham-exposed group. Growth, nutrition and vaginal opening (VO) were regularly monitored. Serum and tissue specimens were collected at puberty. Histological examinations, total antioxidant status (TAS), total oxidant status (TOS) and oxidative stress index (OSI) measurements in ovary and brain tissues and also immunohistochemical staining of the hypothalamus were performed besides the determination of serum FSH, LH, E2 and IGF-1 values. Birth masses of the groups were similar (p > 0.05). Mass gain per day was significantly lower and the puberty was significantly later in the prenatal group. Brain and ovary TOS and OSI values in the prenatal group were significantly increased (p  0.05). Histological examinations of the specimens revealed no statistically significant difference between the groups (p > 0.05). Exposure to 2450 MHz EMF, particularly in the prenatal period, resulted in postnatal growth restriction and delayed puberty in female Wistar rats. Increased TOS and OSI values in the brain and ovary tissues can be interpreted as a sign of chronic stress induced by EMF. This is the first longitudinal study which investigates the effects of EMF induced by wireless internet on pubertal development beside growth.

  11. The physiology and timing of male puberty

    DEFF Research Database (Denmark)

    Tinggaard, Jeanette; Mieritz, Mikkel Grunnet; Sørensen, Kaspar

    2012-01-01

    To describe available markers of male puberty, discuss associations between adiposity and pubertal timing and to review recent evidence of a possible secular trend in male pubertal timing.......To describe available markers of male puberty, discuss associations between adiposity and pubertal timing and to review recent evidence of a possible secular trend in male pubertal timing....

  12. Urinary phthalate excretion in 555 healthy Danish boys with and without pubertal gynaecomastia

    DEFF Research Database (Denmark)

    Mieritz, Mikkel G; Frederiksen, Hanne; Sørensen, Kaspar;

    2012-01-01

    Pubertal gynaecomastia is a clinical sign of an oestrogen-androgen imbalance, which occurs in 40-60% of adolescent Caucasian boys. In most cases no underlying endocrinopathy can be identified. A recent study reports higher plasma phthalate levels in Turkish boys with pubertal gynaecomastia....... Therefore, we asked whether there was an association between concurrent measures of urinary phthalate metabolites and pubertal timing as well as the presence of gynaecomastia in otherwise healthy boys. We studied a total of 555 healthy boys (age 6.07-19.83 years) as part of the COPENHAGEN Puberty Study...

  13. The effects of prenatal exposure to atrazine on pubertal and postnatal reproductive indices in the female rat

    Science.gov (United States)

    Atrazine (ATR) is a commonly used herbicide that can exert negative reproductive effects in animals. We examined the effects of vehicle or ATR at 1, 5, 20 and 100 mg/kg/d, administered to Sprague-Dawley rats on gestational days 14-21, once daily or divided into two doses per day,...

  14. The effects of prenatal exposure to atrazine on pubertal and postnatal reproductive indices in the female rat

    Science.gov (United States)

    Atrazine (ATR) is a commonly used herbicide that can exert negative reproductive effects in animals. We examined the effects of vehicle or ATR at 1, 5, 20 and 100 mg/kg/d, administered to Sprague-Dawley rats on gestational days 14-21, once daily or divided into two doses per day,...

  15. Effect of Radiation Leakage of Microwave Oven on Rat Serum Testosterone at Pre and Post Pubertal Stage

    OpenAIRE

    Zare, Y.; GA Jelodar

    2008-01-01

    Introduction: Since discovery of high frequency waves, their biological effects have been in great attention. Increased male fertility problems proposed their possible relation to use of microwaves. Testes are of very active body tissues, which can be affected by these waves. Age of exposure may also be an important factor. Methods: This study was carried out to evaluated testosterone level in rats exposed to microwave radiation at pre and post puberty. For this study 18 adult (2 month old) a...

  16. Sperm abnormalities induced by pre-pubertal exposure to cyclophosphamide are effectively mitigated by Moringa oleifera leaf extract.

    Science.gov (United States)

    Nayak, G; Vadinkar, A; Nair, S; Kalthur, S G; D'Souza, A S; Shetty, P K; Mutalik, S; Shetty, M M; Kalthur, G; Adiga, S K

    2016-03-01

    Moringa oleifera L. is a medicinal plant with potential antioxidant property. This study was aimed at investigating the chemoprotective effect of Moringa oleifera leaf extract (MOE) on cyclophosphamide (CP)-induced testicular toxicity. Two-week-old male Swiss albino mice were intraperitoneally injected with phosphate-buffered saline, 50 mg kg(-1) of CP and 25 mg kg(-1) of MOE. In combination treatment, mice were injected with 25 mg kg(-1) of MOE 24 h prior to CP injection, 24 h prior and post-CP injection and 24 h post-CP injection for 5 consecutive days (10 mg kg(-1) ). Six weeks later, mice were sacrificed to assess epididymal sperm parameters. MOE alone did not have any significant effect on sperm parameters. However, acute injection of CP resulted in significant decline in motility (P < 0.001), increase in head abnormality (P < 0.01) and DNA damage (P < 0.05). Combining MOE with CP increased the sperm density, motility and reduced head defect and DNA damage, irrespective of the schedule and dosage of MOE. Administration of MOE prior to CP significantly elevated the level of superoxide dismutase and catalase with concomitant decrease in lipid peroxidation in the testicular tissue. In conclusion, MOE may have potential benefit in reducing the loss of male gonadal function following chemotherapy.

  17. Pubertal development in healthy children is mirrored by DNA methylation patterns in peripheral blood

    DEFF Research Database (Denmark)

    Almstrup, Kristian; Johansen, Marie Lindhardt; Busch, Alexander S.

    2016-01-01

    Puberty marks numerous physiological processes which are initiated by central activation of the hypothalamic–pituitary–gonadal axis, followed by development of secondary sexual characteristics. To a large extent, pubertal timing is heritable, but current knowledge of genetic polymorphismsonly...... explains few months in the large inter-individual variation in the timing of puberty. We have analysed longitudinal genome-wide changes in DNA methylation in peripheral blood samples (n = 102) obtained from 51 healthy children before and after pubertal onset. We show that changes in single methylation...... sites are tightly associated with physiological pubertal transition and altered reproductive hormone levels. These methylation sites cluster in and around genes enriched for biological functions related to pubertal development. Importantly, we identified that methylation of the genomic region containing...

  18. Environmental Phenols And Pubertal Development In Girls

    Science.gov (United States)

    Wolff, Mary S.; Teitelbaum, Susan L.; McGovern, Kathleen; Pinney, Susan M.; Windham, Gayle C.; Galvez, Maida; Pajak, Ashley; Rybak, Michael; Calafat, Antonia M.; Kushi, Lawrence H.; Biro, Frank M.

    2015-01-01

    Environmental exposures to many phenols are documented worldwide and exposures can be quite high (>1 micromolar of urine metabolites). Phenols have a range of hormonal activity, but knowledge of effects on child reproductive development is limited, coming mostly from cross-sectional studies. We undertook a prospective study of pubertal development among 1239 girls recruited at three U.S. sites when they were 6–8 years old and were followed annually for 7 years to determine age at first breast or pubic hair development. Ten phenols were measured in urine collected at enrollment (benzophenone-3, enterolactone, bisphenol A, three parabens (methyl-, ethyl-, propyl-), 2,5-dichlorophenol, triclosan, genistein, daidzein). We used multivariable adjusted Cox proportional hazards ratios (HR (95% confidence intervals)) and Kaplan-Meier survival analyses to estimate relative risk of earlier or later age at puberty associated with phenol exposures. For enterolactone and benzophenone-3, girls experienced breast development 5–6 months later, adjusted HR 0.79 (0.64–0.98) and HR 0.80 (0.65–0.98) respectively for the 5th vs 1st quintiles of urinary biomarkers (μg/g-creatinine). Earlier breast development was seen for triclosan and 2,5- dichlorophenol: 4–9 months sooner for 5th vs 1st quintiles of urinary concentrations (HR 1.17 (0.96–1.43) and HR 1.37 (1.09–1.72), respectively). Association of breast development with enterolactone, but not the other three phenols, was mediated by body size. These phenols may be antiadipogens (benzophenone-3 and enterolactone) or thyroid agonists (triclosan and 2,5- dichlorophenol), and their ubiquity and relatively high levels in children would benefit from further investigation to confirm these findings and to establish whether there are certain windows of susceptibility during which exposure can affect pubertal development. PMID:26335517

  19. Breastfeeding versus formula-feeding and girls' pubertal development.

    Science.gov (United States)

    Kale, Aarti; Deardorff, Julianna; Lahiff, Maureen; Laurent, Cecile; Greenspan, Louise C; Hiatt, Robert A; Windham, Gayle; Galvez, Maida P; Biro, Frank M; Pinney, Susan M; Teitelbaum, Susan L; Wolff, Mary S; Barlow, Janice; Mirabedi, Anousheh; Lasater, Molly; Kushi, Lawrence H

    2015-03-01

    To examine the association of breastfeeding or its duration with timing of girls' pubertal onset, and the role of BMI as a mediator in these associations. A population of 1,237 socio-economically and ethnically diverse girls, ages 6-8 years, was recruited across three geographic locations (New York City, Cincinnati, and the San Francisco Bay Area) in a prospective study of predictors of pubertal maturation. Breastfeeding practices were assessed using self-administered questionnaire/interview with the primary caregiver. Girls were seen on at least annual basis to assess breast and pubic hair development. The association of breastfeeding with pubertal timing was estimated using parametric survival analysis while adjusting for body mass index, ethnicity, birth-weight, mother's education, mother's menarcheal age, and family income. Compared to formula fed girls, those who were mixed-fed or predominantly breastfed showed later onset of breast development [hazard ratios 0.90 (95 % CI 0.75, 1.09) and 0.74 (95 % CI 0.59, 0.94), respectively]. Duration of breastfeeding was also directly associated with age at onset of breast development (p trend = 0.008). Associations between breastfeeding and pubic hair onset were not significant. In stratified analysis, the association of breastfeeding and later breast onset was seen in Cincinnati girls only. The association between breast feeding and pubertal onset varied by study site. More research is needed about the environments within which breastfeeding takes place in order to better understand whether infant feeding practices are a potentially modifiable risk factor that may influence age at onset of breast development and subsequent risk for disease in adulthood.

  20. Breastfeeding versus Formula-Feeding & Girls’ Pubertal Development

    Science.gov (United States)

    Kale, Aarti; Deardorff, Julianna; Lahiff, Maureen; Laurent, Cecile; Greenspan, Louise C.; Hiatt, Robert A.; Windham, Gayle; Galvez, Maida P.; Biro, Frank M.; Pinney, Susan M.; Teitelbaum, Susan L.; Wolff, Mary S.; Barlow, Janice; Mirabedi, Anousheh; Lasater, Molly; Kushi, Lawrence H.

    2014-01-01

    Objective To examine the association of breastfeeding or its duration with timing of girls’ pubertal onset, and the role of BMI as a mediator in these associations. Methods A population of 1,237 socio-economically and ethnically diverse girls, ages 6–8 years, was recruited across three geographic locations (New York City, Cincinnati, and the San Francisco Bay Area) in a prospective study of predictors of pubertal maturation. Breastfeeding practices were assessed using self-administered questionnaire/interview with the primary caregiver. Girls were seen on at least annual basis to assess breast and pubic hair development. The association of breastfeeding with pubertal timing was estimated using parametric survival analysis while adjusting for body mass index, ethnicity, birth-weight, mother’s education, mother’s menarcheal age, and family income. Results Compared to formula fed girls, those who were mixed-fed or predominantly breastfed showed later onset of breast development (Hazard Ratios 0.90 [95% CI, 0.75–1.09] and 0.74 [95% CI, 0.59–0.94], respectively). Duration of breastfeeding was also directly associated with age at onset of breast development (p trend = 0.008). Associations between breastfeeding and pubic hair onset were not significant. In stratified analysis, the association of breastfeeding and later breast onset was seen in Cincinnati girls only. Conclusion The association between breast feeding and pubertal onset varied by study site. More research is needed about the environments within which breastfeeding takes place in order to better understand whether infant feeding practices are a potentially modifiable risk factor that may influence age at onset of breast development and subsequent risk for disease in adulthood. PMID:24916206

  1. DNA Methylation Patterns in the Hypothalamus of Female Pubertal Goats.

    Science.gov (United States)

    Yang, Chen; Ye, Jing; Li, Xiumei; Gao, Xiaoxiao; Zhang, Kaifa; Luo, Lei; Ding, Jianping; Zhang, Yunhai; Li, Yunsheng; Cao, Hongguo; Ling, Yinghui; Zhang, Xiaorong; Liu, Ya; Fang, Fugui

    2016-01-01

    Female pubertal development is tightly controlled by complex mechanisms, including neuroendocrine and epigenetic regulatory pathways. Specific gene expression patterns can be influenced by DNA methylation changes in the hypothalamus, which can in turn regulate timing of puberty onset. In order to understand the relationship between DNA methylation changes and gene expression patterns in the hypothalamus of pubertal goats, whole-genome bisulfite sequencing and RNA-sequencing analyses were carried out. There was a decline in DNA methylation levels in the hypothalamus during puberty and 268 differentially methylated regions (DMR) in the genome, with differential patterns in different gene regions. There were 1049 genes identified with distinct expression patterns. High levels of DNA methylation were detected in promoters, introns and 3'-untranslated regions (UTRs). Levels of methylation decreased gradually from promoters to 5'-UTRs and increased from 5'-UTRs to introns. Methylation density analysis demonstrated that methylation level variation was consistent with the density in the promoter, exon, intron, 5'-UTRs and 3'-UTRs. Analyses of CpG island (CGI) sites showed that the enriched gene contents were gene bodies, intergenic regions and introns, and these CGI sites were hypermethylated. Our study demonstrated that DNA methylation changes may influence gene expression profiles in the hypothalamus of goats during the onset of puberty, which may provide new insights into the mechanisms involved in pubertal onset.

  2. Sex steroids and brain structure in pubertal boys and girls.

    Science.gov (United States)

    Peper, Jiska S; Brouwer, Rachel M; Schnack, Hugo G; van Baal, G Caroline; van Leeuwen, Marieke; van den Berg, Stéphanie M; Delemarre-Van de Waal, Henriëtte A; Boomsma, Dorret I; Kahn, René S; Hulshoff Pol, Hilleke E

    2009-04-01

    Sex steroids exert important organizational effects on brain structure. Early in life, they are involved in brain sexual differentiation. During puberty, sex steroid levels increase considerably. However, to which extent sex steroid production is involved in structural brain development during human puberty remains unknown. The relationship between pubertal rises in testosterone and estradiol levels and brain structure was assessed in 37 boys and 41 girls (10-15 years). Global brain volumes were measured using volumetric-MRI. Regional gray and white matter were quantified with voxel-based morphometry (VBM), a technique which measures relative concentrations ('density') of gray and white matter after individual global differences in size and shape of brains have been removed. Results showed that, corrected for age, global gray matter volume was negatively associated with estradiol levels in girls, and positively with testosterone levels in boys. Regionally, a higher estradiol level in girls was associated with decreases within prefrontal, parietal and middle temporal areas (corrected for age), and with increases in middle frontal-, inferior temporal- and middle occipital gyri. In boys, estradiol and testosterone levels were not related to regional brain structures, nor were testosterone levels in girls. Pubertal sex steroid levels could not explain regional sex differences in regional gray matter density. Boys were significantly younger than girls, which may explain part of the results. In conclusion, in girls, with the progression of puberty, gray matter development is at least in part directly associated with increased levels of estradiol, whereas in boys, who are in a less advanced pubertal stage, such steroid-related development could not (yet) be found. We suggest that in pubertal girls, estradiol may be implicated in neuronal changes in the cerebral cortex during this important period of brain development.

  3. Recent secular trends in pubertal timing

    DEFF Research Database (Denmark)

    Sørensen, Kaspar; Mouritsen, Annette; Aksglaede, Lise

    2012-01-01

    The decline in age at puberty in the general population has been paralleled by an increase in the number of girls referred for evaluation of precocious puberty (PP). In 1999, The Lawson Wilkins Pediatric Endocrine Society recommended a lowering of the age limit for evaluation of PP in girls. Howe...

  4. Electro convulsive therapy in a pre-pubertal child with severe depression.

    Directory of Open Access Journals (Sweden)

    Russell P

    2002-10-01

    Full Text Available Electro Convulsive Therapy (ECT in pre-pubertal children is a controversial and underreported treatment. Even though the effectiveness and side effects of ECT in adolescents are comparable with those in adults, there is a pervasive reluctance to use ECT in children and adolescents. We report the case of a pre-pubertal child in an episode of severe depression with catatonic features, where a protracted course of ECT proved life-saving in spite of prolonged duration of seizures and delayed response to treatment. The case illustrates the safety and efficacy of ECT in children. Relevant literature is also reviewed along with the case report.

  5. 口服雌激素、孕激素、避孕药治疗青春期功能性子宫出血的效果%The therapeutic effects of oral administration of estrogen,progestogen and contraceptive in pubertal dysfunctional uterine bleeding

    Institute of Scientific and Technical Information of China (English)

    孙春玲; 袁桂兰; 章颖

    2011-01-01

    目的:比较口服雌激素、孕激素、避孕药治疗青春期功能性子宫出血的效果.方法:选取北京市海淀医院2006年1月~2010年8月门诊和住院收治的51例青春期功能性子宫出血患者,按照随机对照法分为3组,即雌激素组(15例)、孕激素组(16例)及口服避孕药组(20例).对3组患者的快速控制出血率、快速完全止血率、完全止血成功率、控制出血时间及完全止血时间进行记录和评价.结果:在快速控制出血、快速完全止血及完全止血成功三方面比较,孕激素组及口服避孕药组明显高于雌激素组(P<0.05);孕激素组及口服避孕药组患者的控制出血时间、完全止血时间明显低于雌激素组(P<0.01).结论:在治疗青春期功能性子宫出血效果方面,口服孕激素和口服避孕药的效果优于口服雌激素.%Objective; To compare the therapeutic effects of oral administration of estrogen, progestogen and contraceptive in pu-bertal dysfunctional uterine bleeding. Methods; 51 cases with pubertal dysfunctional uterine bleeding were selected from the hospital from January 2006 to August 2010, then they were randomly divided into estrogen group (15 cases) , progestogen group (16 cases) and contraceptive group (20 cases) . The quick control rate of bleeding, quick total hemostasis rate, success rate of total hemostasis, control bleeding time and time of total hemostasis in the three groups were recorded and evaluated. Results; The quick control rate of bleeding, quick total hemostasis rate and success rate of total hemostasis in progestogen group and contraceptive group were significantly higher than those in estrogen group ( P < 0. 05) . The control bleeding time and time of total hemostasis in progestogen group and contraceptive group were significantly lower than those in estrogen group (P <0. 01) . Conclusion; The effects of oral administration of progestogen and contraceptive are better than that of oral administration

  6. Maths performance as a function of sex, laterality, and age of pubertal onset.

    Science.gov (United States)

    Sappington, John; Topolski, Richard

    2005-07-01

    Sex differences in math/spatial performance demand explanations. Within the biological view, the complexity and number of variables make the explanation difficult at best. Laterality and age of pubertal onset have been investigated prominently in this context but rarely considered as interactions in the same study. Some 468 college subjects with SAT MATH (SAT M) scores were divided into 12 groups defined by sex, laterality, and age (early, middle, and late) of pubertal onset. Significant main effects for sex and age of onset emerged, as did an interaction between lateral preference and pubertal onset. Generally males outperformed females. The combination of maleness, sinistrality, and early maturation was associated with high SAT M scores. Sinistrality and late maturation among females predicted very poor math performance.

  7. Advances in pubertal growth and factors influencing it: Can we increase pubertal growth?

    Directory of Open Access Journals (Sweden)

    Ashraf Soliman

    2014-01-01

    Full Text Available Puberty is a period of development characterized by partially concurrent changes which includes growth acceleration, alteration in body composition and appearance of secondary sex characteristics. Puberty is characterized by an acceleration and then deceleration in skeletal growth. The initiation, duration and amount of growth vary considerably during the growth spurt. Pubertal growth and biological maturation are dynamic processes regulated by a variety of genetic and environmental factors. Changes in skeletal maturation and bone mineral accretion concomitant with the stage of pubertal development constitute essential components in the evaluation of growth during this pubertal period. Genetic, endocrine and nutritional factors and ethnicity contribute variably to the amount of growth gained during this important period of rapid changes. Many studies investigated the possibility of increasing pubertal growth to gain taller final adult height in adolescents with idiopathic short stature (ISS. The pattern of pubertal growth, its relation to sex maturity rating and factors affecting them has been addressed in this review. The results of different trials to increase final adult height of adolescents using different hormones have been summarized. These data enables Endocrinologists to give in-depth explanations to patients and families about the efficacy and clinical significance as well as the safety of using these therapies in the treatment of adolescents with ISS.

  8. Arthrospira (Spirulina) platensis supplementation affects folliculogenesis, progesterone and ghrelin levels in fattening pre-pubertal gilts

    NARCIS (Netherlands)

    Abadjieva, Desislava; Nedeva, Radka; Marchev, Yordan; Jordanova, Gergana; Chervenkov, Mihail; Dineva, Julieta; Shimkus, Almantas; Shimkiene, Aldona; Teerds, Katja; Kistanova, Elena

    2017-01-01

    The aim of the present investigation was to study the effect of Arthrospira (Spirulina) platensis supplemented diet on follicular development and related endocrine parameters, such as estradiol and progesterone levels as well as ghrelin levels in pre-pubertal gilts. Twenty-one 60-day-old Danube

  9. A combined form of hypothyroidism in pubertal patients with non-mosaic Klinefelter syndrome.

    Science.gov (United States)

    Tahani, Natascia; Ruga, Gilda; Granato, Simona; Spaziani, Matteo; Panimolle, Francesca; Anzuini, Antonella; Lenzi, Andrea; Radicioni, Antonio Francesco

    2017-02-01

    Klinefelter syndrome has been associated with thyroid abnormalities, the genesis of which is not yet fully clear. The aim of this study was to evaluate thyroid function in Klinefelter syndrome subjects during the pubertal period. Chemiluminescent microparticle immunoassay was used to analyze Thyroid-Stimulating Hormone, fT3 and fT4 concentration in serum samples from 40 Klinefelter syndrome pubertal boys with classic 47,XXY karyotype and 157 healthy age-matched controls. 13 Klinefelter syndrome patients also underwent Thyrotropin-Releasing Hormone testing to evaluate hypothalamic-pituitary function. fT3 levels were significantly lower in Klinefelter syndrome patients than in age-matched controls (p Klinefelter syndrome patients tended to cluster around the lower part of the reference range for the assay. Three of the thirteen Klinefelter syndrome patients undergoing the Thyrotropin-Releasing Hormone test had an adequate response, one had a prolonged response at 60 min and nine responded inadequately. This study demonstrated for the first time that pubertal Klinefelter syndrome patients have significantly lower fT3 serum levels than do healthy age-matched boys, whereas Thyroid-Stimulating Hormone and fT4 are normal, albeit at the lower end of the reference range. Most patients showed an inadequate/prolonged response to pituitary stimulation with Thyrotropin-Releasing Hormone. These findings suggest a combined form of both central and peripheral hypothyroidism in Klinefelter syndrome boys during pubertal development.

  10. [Insulin resistance and hyperinsulinemia--risk factors of the metabolic syndrome in the pubertal population].

    Science.gov (United States)

    Otto Buczkowska, Ewa

    2005-01-01

    Pubertal insulin resistance has been well documented, the fall in insulin sensitivity (Sl) during puberty is associated with a compensatory increase in insulin secretion. Observation of pubertal insulin resistance showed that insulin-stimulated glucose metabolism was approximately 30% lower in a sample of children at Tanner stages II-IV compared with children at Tanner stage I or adults. Although the phenomenon of pubertal insulin resistance is well documented, the mechanism has not been clearly determined. Pubertal insulin resistance occurs during a time of profound changes in body composition and hormone levels. Resistance of the body to the actions of insulin results in increased production of this hormone by the pancreas and ensuing hyperinsulinemia. Obesity beginning in childhood often precedes the hyperinsulinemic state. Other components of the insulin resistance syndrome are also present in children and adolescents. Conditions of insulin resistance, hyperinsulinemia, dyslipidemia, hypertension and obesity, especially in constellation, are potent risk factors of coronary atherosclerosis among adolescents and young adults. Early conservative intervention with diet, exercise, and behavioral therapy may prevent the complications of insulin resistance.

  11. Plasma Nesfatin-1 and Leptin in pubertal and non-pubertal Murrah buffalo heifers (Bubalus bubalis

    Directory of Open Access Journals (Sweden)

    Gorakh Nath Prajapati

    2015-12-01

    Full Text Available Buffaloes mostly suffer from delayed puberty, anestrus, sub–estrus, summer infertility, prolonged inter-calving interval and postpartum uterine disorders. Nesfatin-1 and Leptin are directly or indirectly related with body weight (BW, feed parameters and regulation of puberty. The objective of this study was to investigate the influence of Nesfatin-1 and Leptin in pubertal and non-pubertal Murrah buffalo heifers. The Murrah buffalo heifers (n=13 were randomly selected and divided into two groups; pubertal group (PG and non-pubertal group (NG. Heifers with plasma progesterone (P4 level of ≥1 ng/mL were classified as PG. Blood samples were collected at fortnight intervals for analysis of plasma Nesfatin-1, Leptin, P4, glucose and non-esterified fatty acids. Body weight, dry matter intake and feed conversion efficiency were recorded at fortnight intervals. The mean (±SEM plasma Nesfatin-1, Leptin, P4, BW and feed conversion efficiency (% were significantly (P<0.01 higher in PG as compared to NG. Dry matter intake by the heifers was also significantly (P<0.001 higher in PG than NG. Plasma metabolites (glucose and NEFA did not differ significantly between the groups. The findings of this study suggest that Nesfatin-1 and Leptin have indispensable role in the onset of puberty in buffalo heifers by affecting BW and feed parameters.

  12. The pubertal transition in 179 healthy Danish children

    DEFF Research Database (Denmark)

    Mouritsen, Annette; Aksglæde, Lise; Sørensen, Kaspar

    2013-01-01

    Pubertal onset is usually defined by breast development in girls and testicular growth in boys. Pubarche is defined as the attainment of pubic hair and is considered as a sign of pubertal transition. Pubarche is preceded by a gradual increase in production of adrenal androgens, DHEA and Δ4...

  13. Pubertal development in The Netherlands 1965-1997

    NARCIS (Netherlands)

    D. Mul (Dick); A.M. Fredriks; S. van Buuren (Stef); W. Oostdijk (Wilma); S.P. Verloove-Vanhorick; J.M. Wit (Jan)

    2001-01-01

    textabstractWe investigated pubertal development of 4019 boys and 3562 girls >8 y of age participating in a cross-sectional survey in The Netherlands and compared the results with those of two previous surveys. Reference curves for all pubertal stages were constructed. The 50th per

  14. Pubertal development in The Netherlands 1965-1997

    NARCIS (Netherlands)

    D. Mul (Dick); A.M. Fredriks; S. van Buuren (Stef); W. Oostdijk (Wilma); S.P. Verloove-Vanhorick; J.M. Wit (Jan)

    2001-01-01

    textabstractWe investigated pubertal development of 4019 boys and 3562 girls >8 y of age participating in a cross-sectional survey in The Netherlands and compared the results with those of two previous surveys. Reference curves for all pubertal stages were constructed. The 50th per

  15. Prevalence and incidence of precocious pubertal development in Denmark

    DEFF Research Database (Denmark)

    Teilmann, Grete; Pedersen, Carsten; Jensen, Tina Kold

    2005-01-01

    To our knowledge, no population-based epidemiologic studies on the incidence and prevalence of precocious pubertal development have been published. Danish national registries provide sufficient data for estimating the prevalence and incidence of this condition. The aim of this study was to estimate...... the prevalence and incidence of precocious pubertal development in Denmark in a 9-year period....

  16. Reproductive ability of pubertal male and female rats

    Directory of Open Access Journals (Sweden)

    T. Zemunik

    2003-07-01

    Full Text Available Ten Fisher rats 50 to 55 days of age made up the pubertal group, and ten rats 90 to 95 days of age served as the controls. The testicular and epididymal weights and volumes of the pubertal males were lower than those of the controls (P0.05. At the beginning of gestation, the pubertal dams weighed less than the controls (P<0.001 but following uterectomy the body weights were equal. Pubertal dams delivered fewer pups than the controls (8.1 ± 2.5 vs 10.4 ± 1.3, P<0.05. There was no difference in the body weights of their offspring or in the weights of their placentas. The results suggest that, in contrast to their female counterparts, pubertal male rats are not fully mature and have not reached complete reproductive capacity at 50-55 days of age.

  17. [Psychopathology related to women pubertal precocity].

    Science.gov (United States)

    Purper-Ouakil, D; Didillon, A

    2016-10-01

    associated with psychosocial stressors and at-risk environments. The early development of secondary sexual characteristics in girls attracts older and more deviant peers, raising probability of sexual contacts but also of drug use and of a disengagement in school activities. Adolescence is the life stage during which prevalence of depressive disorders rises significantly, especially in girls. Hormonal changes and increase of the Body Mass Index leading to dissatisfaction with body image, have been put forward to explain this trend. Psychosocial challenges (emerging sexuality, instability of identity and social role) are other sources of stress at this particular period of life characterized by emotional hyper-reactivity. These stressors may have greater impact in young people showing a discrepancy between physical and affective maturation. Follow-up studies have shown that emotional and behavioral problems tend to lessen with time. Nevertheless, a heightened risk of depressive disorder remains in girls having had an early onset of puberty when other risk factors co-exist. Early puberty, especially in girls, has been associated with a number of emotional and behavioral symptoms and difficulties in adaptive functioning. Even though these adverse outcomes seem to lessen with time, heightened risk for depression and negative impact on socio-professional outcomes persist in subjects with other risk factors. The impact of treatment of precocious puberty on psycho-behavioral outcomes is currently unknown. However, clinicians should be aware that the social and emotional challenges these adolescents with atypical pubertal development have to face put them at risk for psychopathology and are potentially accessible to preventive actions. Copyright © 2016 L'Encéphale, Paris. Published by Elsevier Masson SAS. All rights reserved.

  18. Evidence of secular trend in mandibular pubertal growth.

    Science.gov (United States)

    Patcas, Raphael; Wiedemeier, Daniel B; Markic, Goran; Beit, Philipp; Keller, Heidi

    2017-04-20

    During puberty, mandibular growth follows a growth curve comparable to somatic growth. This study aimed to review the relationship between mandibular pubertal peak height velocity (PHV) and skeletal age, and to investigate the possibility of a secular trend. Retrospective analysis was performed of two historical craniofacial growth studies (Denver Growth Study; observational time: 1943-1965, and Zurich Growth Study; observational time: 1982-1984) of healthy untreated subjects. Two mandibular growth measures (Articulare-Pogonion [Ar-Pg], Condylion-Pogonion [Co-Pg]) were retrieved from cephalograms (n: 990) and corresponding skeletal age based on hand-wrist radiographs. Mandibular growth velocity was related to skeletal age, PHV was established by use of cubic smoothing splines and variability was calculated by bootstrap resampling for every growth study and gender separately. Sexual dimorphism in mandibular growth was apparent in both cohorts. In subjects of the Denver Growth Study, mandibular PHV occurred at a more advanced skeletal age than in subjects of the Zurich Growth Study. This trend was more pronounced in males, for whom PHV of Co-Pg shifted from 14.4 to 13.8 years and of Ar-Pg from 14.6 to 13.7 years. This tendency was more subtle in females: PHV of Co-Pg shifted from 12.7 to 12.4 years and of Ar-Pg from 12.6 to 11.8 years. Mandibular growth appears to be subject to a secular trend. When related to skeletal age, this secular trend seems to be more accentuated than the established secular trend for somatic pubertal growth.

  19. Stress induced alterations in pre-pubertal ovarian follicular development in rat

    Directory of Open Access Journals (Sweden)

    Yajurvedi H.N.

    2011-12-01

    Full Text Available The objective of the study was to find out whether stress experienced during neo-natal period alters the timing of formation of pre-antral and antral follicles and if so, whether pre-treatment with CRH receptor antagonist prevents these effects in rats. New born rat pups (n= 15 were exposed to maternal separation (6 hours/ day from post-natal day (PND 1 to 7 and were killed on PND 8, 11 and 15. The time of exposure was randomly changed every day during light phase (7Am to 7Pm of the day to avoid habituation. There was a significant increase in serum corticosterone levels on PND 8 and 11 in stress group rats compared to controls indicating stress response in these pups. The ovary of both control and stressed rats contained oocytes and primary follicles on PND 8 and 11 and in showed progress of follicular development upto to pre-antral and early antral follicle formation on PND 11 and 15. However, mean number of healthy oocytes and all categories of follicles at all ages studied were significantly lower in stressed rats compared to controls. Concomitant with these changes, number of atreatic follicles showed an increase over control values in stressed rats. The increase in atresia of follicles was due to apoptosis as shown by increase in the percentage of granulosa cells showing TUNEL positive staining and caspase 3 activity. On the other hand, pre-treatment with CRH- receptor antagonist (CRH 9-41 2ng/ 0.1 ml/ rat prior to undergoing stress regime on PND 1 to 7, prevented alterations in pre- pubertal follicular development thereby indicating that the ovarian changes were due to effects of stress induced activation of HPA axis. The results indicate that, stress during neonatal phase, though does not affect timing of formation of pre-antral and antral follicles, it does enhance atresia of follicles of all categories, including follicular reserve, which may affect the reproductive potential of adults. The results, for the first time reveal that CRF

  20. The long-term effects of FSH and triiodothyronine administration during the pubertal period on Connexin 43 expression and spermatogenesis efficiency in adult rats.

    Science.gov (United States)

    Marchlewska, Katarzyna; Slowikowska-Hilczer, Jolanta; Walczak-Jedrzejowska, Renata; Oszukowska, Elzbieta; Filipiak, Eliza; Kula, Krzysztof

    2015-04-01

    Follicle-stimulating hormone (FSH) and triiodothyronine (T3) are known regulatory factors of spermatogenesis initiation. Hyperstimulation of both hormones evokes regressional changes in connexin 43 expression and the seminiferous epithelium in young rats during testicular maturation. However, separate treatments with T3 reduce Sertoli cell number, which seems to be closely connected with the maturation of connexin 43 gap junctions. FSH elevates Sertoli cell number and function, but this effect may take place regardless of the presence of connexin 43-dependent intercellular communication. The aim of the study was to evaluate the later effects of such treatments. Newborn, male Wistar rats were divided randomly into experimental groups receiving daily subcutaneous injections of either 7.5 IU/animal FSH, or 100 mg/kg b.w. T3, or both substances or the same volume of vehicle (control group) until day 15 of life. The animals were sacrificed on day 50. Morphometric analysis and immunohistochemical reactions were performed using antibodies against Vimentin, Proliferating Cell Nuclear Antigen and Connexin 43 in the testis. Sertoli cell count, efficiency of spermatogenesis, and hormonal pattern were examined. Disturbances in the connexin 43 expression reduced the number of Sertoli cells, the efficiency of spermatogenesis and impaired endocrine function of testes in adult rats treated with FSH and T3 during puberty. Stimulation with FSH alone increased Sertoli cell number, but was associated with a negative effect on cell-to-cell connexin 43-dependent communication, with a consequential reduction of spermatogenesis efficiency. J. Exp. Zool. 323A: 256-265, 2015. © 2015 Wiley Periodicals, Inc.

  1. Does neighborhood environment influence girls' pubertal onset? findings from a cohort study

    Directory of Open Access Journals (Sweden)

    Deardorff Julianna

    2012-03-01

    Full Text Available Abstract Background Pubertal onset occurs earlier than in the past among U.S. girls. Early onset is associated with numerous deleterious outcomes across the life course, including overweight, breast cancer and cardiovascular health. Increases in childhood overweight have been implicated as a key reason for this secular trend. Scarce research, however, has examined how neighborhood environment may influence overweight and, in turn, pubertal timing. The current study prospectively examined associations between neighborhood environment and timing of pubertal onset in a multi-ethnic cohort of girls. Body mass index (BMI was examined as a mediator of these associations. Methods Participants were 213 girls, 6-8 years old at baseline, in an on-going longitudinal study. The current report is based on 5 time points (baseline and 4 annual follow-up visits. Neighborhood environment, assessed at baseline, used direct observation. Tanner stage and anthropometry were assessed annually in clinic. Survival analysis was utilized to investigate the influence of neighborhood factors on breast and pubic hair onset, with BMI as a mediator. We also examined the modifying role of girls' ethnicity. Results When adjusting for income, one neighborhood factor (Recreation predicted delayed onset of breast and pubic hair development, but only for African American girls. BMI did not mediate the association between Recreation and pubertal onset; however, these associations persisted when BMI was included in the models. Conclusions For African American girls, but not girls from other ethnic groups, neighborhood availability of recreational outlets was associated with onset of breast and pubic hair. Given the documented risk for early puberty among African American girls, these findings have important potential implications for public health interventions related to timing of puberty and related health outcomes in adolescence and adulthood.

  2. Male pre- and post-pubertal castration effect on live weight, components of empty body weight, estimated nitrogen excretion and efficiency in Piemontese hypertrofic cattle

    Directory of Open Access Journals (Sweden)

    Davide Biagini

    2011-04-01

    Full Text Available To evaluate the effect of sexual neutering and age of castration on empty body weight (EBW components and estimated nitrogen excretion and efficiency, a trial was carried out on 3 groups of double-muscled Piemontese calves: early castrated (EC, 5th month of age, late castrated (LC, 12th month of age and intact males (IM, control group. Animals were fed at the same energy and protein level and slaughtered at 18th month of age. Live and slaughtering performances and EBW components were recorded, whereas N excretion was calculated by difference between diet and weight gain N content. In live and slaughtering performances, IM showed higher final, carcass and total meat weight than EC and LC (P<0.01. In EBW components, IM showed higher blood and head weight than EC and LC (P<0.01 and 0.05 respectively, and differences were found between EC and LC for head weights (P<0.01. IM showed higher body crude protein (BCP than EC and LC (P<0.01 and 0.05 respectively, but BCP/EBW ratio was higher only in IM than EC (P<0.05. Estimated N daily gain was higher in IM than EC and LC (P<0.01. Only LC showed higher excretion than IM (P<0.05, and N efficiency was higher in IM than EC and LC (P<0.05 and 0.01 respectively. In conclusion, for the Piemontese hypertrophied cattle castration significantly increases N excretion (+7% and reduces N efficiency (-15%, leading to a lower level of sustainability.

  3. The effect of dairy intake on bone mass and body composition in early pubertal girls and boys: a randomized controlled trial.

    Science.gov (United States)

    Vogel, Kara A; Martin, Berdine R; McCabe, Linda D; Peacock, Munro; Warden, Stuart J; McCabe, George P; Weaver, Connie M

    2017-03-22

    Background: Calcium retention increases with increasing body mass index (BMI) on recommended calcium intakes. Dairy foods are an excellent source of essential nutrients that are needed to increase bone mineral content (BMC) and potentially decrease fracture.Objective: We compared children who were overweight with children who were healthy weight for the accrual of bone mass in response to an extra 3 servings dairy/d compared with usual intake.Design: Participants were 240 healthy boys and girls (64%), aged 8-15.9 y (mean ± SD age: 11.8 ± 1.5 y), who consumed low amounts of dairy (dairy intervention (3 servings/d equivalent to ∼900 mg Ca/d) or control. Main outcome measures assessed every 6 mo included the total-body bone mineral content and density, cortical and trabecular bone mineral density (BMD), BMC, and bone area at the 4% tibia and anthropometric measures.Results: No significant differences in the change of BMD, BMC, or bone area for the total-body radius, lumbar spine, and total hip were observed between subjects who received the dairy intervention (achieved consumption of 1500 mg Ca/d) and subjects who did not (achieved 1000 mg Ca/d, which represented ∼2 cups milk or other dairy as part of the diet) with the exception of a tibial BMC gain, which was greater in the group who were given dairy (P = 0.02). Body fat was not influenced by the diet assignment.Conclusions: Dairy food interventions generally had no effect on bone mineral acquisition or body composition either within or between weight groups. This study suggests that 2 cups milk or the dairy equivalent is adequate for normal bone gain between ages 8 and 16 y. This trial was registered at clinicaltrials.gov as NCT00635583.

  4. Pubertal Onset in Girls is Strongly Influenced by Genetic Variation Affecting FSH Action

    Science.gov (United States)

    Hagen, Casper P.; Sørensen, Kaspar; Aksglaede, Lise; Mouritsen, Annette; Mieritz, Mikkel G.; Tinggaard, Jeanette; Wohlfart-Veje, Christine; Petersen, Jørgen Holm; Main, Katharina M.; Meyts, Ewa Rajpert-De; Almstrup, Kristian; Juul, Anders

    2014-01-01

    Age at pubertal onset varies substantially in healthy girls. Although genetic factors are responsible for more than half of the phenotypic variation, only a small part has been attributed to specific genetic polymorphisms identified so far. Follicle-stimulating hormone (FSH) stimulates ovarian follicle maturation and estradiol synthesis which is responsible for breast development. We assessed the effect of three polymorphisms influencing FSH action on age at breast deveopment in a population-based cohort of 964 healthy girls. Girls homozygous for FSHR -29AA (reduced FSH receptor expression) entered puberty 7.4 (2.5–12.4) months later than carriers of the common variants FSHR -29GG+GA, p = 0.003. To our knowledge, this is the strongest genetic effect on age at pubertal onset in girls published to date. PMID:25231187

  5. Impact of pubertal development on endothelial function and arterial elasticity.

    Science.gov (United States)

    Marlatt, Kara L; Steinberger, Julia; Dengel, Donald R; Sinaiko, Alan; Moran, Antoinette; Chow, Lisa S; Steffen, Lyn M; Zhou, Xia; Kelly, Aaron S

    2013-11-01

    Little is known about the relation of pubertal development on endothelial function and arterial elasticity in children and adolescents; therefore, we compared brachial artery flow-mediated dilation and carotid artery elasticity across Tanner (pubertal) stages in children and adolescents. Blood pressure, fasting lipids, glucose and insulin, body fat, insulin sensitivity adjusted for lean body mass, brachial flow-mediated dilation (percent dilation and area under the curve), endothelium-independent dilation (peak dilation and area under the curve), and carotid artery elasticity were evaluated across pubertal stages (Tanner I vs Tanner II-IV vs Tanner V) in 344 children and adolescents (184 males, 160 females; ages 6 to 21 years). One hundred twenty-four subjects (mean age 8.23 ± 0.15 years; 52 females) were Tanner stage I; 105 subjects (mean age 13.19 ± 0.17 years; 47 females) were Tanner stages II-IV; and 115 subjects (mean age 17.19 ± 0.16 years; 61 females) were Tanner stage V. There were no significant differences for any of the measures of vascular structure and function across pubertal stages. Results of the current study indicate that smooth-muscle and endothelial function, as well as carotid artery elasticity, do not differ throughout pubertal development and that accounting for pubertal stage when reporting vascular data in children and adolescents may be unnecessary. Copyright © 2013 Mosby, Inc. All rights reserved.

  6. 北京青春期女孩低体重及其对健康影响的研究%Low body weight and its health effect on pubertal girls in Bei jing

    Institute of Scientific and Technical Information of China (English)

    郑皖华; 杜学勤; 刘忠厚

    2001-01-01

    Objective To investigate the prevalence of low body w eight or thinness in Beijing pubertal girls and the cut-off body mass index(BMI )for Chinese pubertal girls. Methods Data used for the analyses were drawn from a random sampl e of 1214 adolescent girls aged 12-13 years from rural and urban areas of Beijin g,China,in a nutritional survey in 1995.Variables included age,height,weight,BMI ,bone age,menarche,breast and pubic hair development,bone mineral content(BMC),b one mineral density(BMD)and bone width(BW)at distal 1/3 and 1/10 radius and ulna .BMI assessment criteria established by Chinese Ministry of Health and State Edu cation Commission and WHO recommendation on BMI-for-age were used. Results The low body weight(BMI<18) rate was 32.2%.Compared wi th those with normal weight, the girls with low body weight had lower bone age, delayed breast and pubic hair development, lower menarche rate,and lower BMC,BMD and BW at distal 1/3 radius and ulna (P<0.05).Logistic regression analys is showed that BW,bone age,breast development and BMI were determinants/predicto rs of BMC of the forearm.When BMI<18,the risk of BMC at 1/3 ulna less than the median was 1.75 times of that when BMI=18-21. Conclusion High pre vale nce of low body weight was a major nutritional health problem among Beijing pube rt al girls.BMI<18 is recommended as the cut-off value for delayed growth and deve lopment as well as at risk of low BMD.Menarche is a useful indicator of nutritio nal status.Nutritional interventions need to be introduced to girls with low body weight to improve their growth and bone health.%目的 调查青春期女孩低体重率并探讨适合我国青春期女孩体重指数(BMI)的评 价标准。方法 对1214名北京城乡12~13岁女学生1995年营养状况调查的 样本资料进行分析,指标包括年龄、身高、体重、BMI、骨龄、月经初潮、第二性征发育、 左前臂远端1/3和1/10位点桡尺骨骨矿含量、骨密度、骨宽度

  7. Transitions in Body and Behavior: A Meta-Analytic Study on the Relationship Between Pubertal Development and Adolescent Sexual Behavior

    NARCIS (Netherlands)

    Baams, L.; Dubas, J.S.; Overbeek, G.J.; van Aken, M.A.G.

    2015-01-01

    The present meta-analysis studies the relations of pubertal timing and status with sexual behavior and sexual risk behavior among youth aged 10.5-22.4 years. We included biological sex, age, and ethnicity as potential moderators. Four databases were searched for studies (published between 1980 and 2

  8. [Peculiarities of sexual behavior of female rats with hyperandrogenia in pubertal and postpubertal periods].

    Science.gov (United States)

    Nosenko, N D; Lymarieva, A A

    2013-01-01

    The parameters of female and male sexual behavior in 3- and 6- month old female rats which were exposed to an androgen excess (subcutaneous implantation of Silastic capsules containing 5 mg of crystalline testosterone) from the beginning of pubertal period (at the age of 35 days), or within postpubertal period (at the age of 4 months). Hyperandrogenia in pubertal period had no effect on female sexual behavior formation, but it led to appearance of male behavior components in 100% of animals. In female rats which were implanted with testosterone capsules in postpubertal period, sexual disturbances were more pronounced and were characterized by masculinization and defeminization, which was due to a higher degree of androgenic saturation. The data obtained suggest a leading role of hyperandrogenemia in the pathogenesis of sexual behavior disturbances in female rats in different periods of individual development.

  9. Stimulation of gonadal development by sexual interaction of pubertal African catfish, Clarias gariepinus.

    Science.gov (United States)

    van Weerd, J H; Sukkel, M; Bongers, A B; van der Does, H M; Steynis, E; Richter, C J

    1991-02-01

    Stimulation and inhibition of gonadal development by intersexual contact was studied in pubertal African catfish, Clarias gariepinus. The effect of a possible interaction was studied by evaluation after a 98-day experimental period of gonadal development in combinations of intact and anosmic males and females. In addition, separate groups of males and females, respectively, were exposed to holding water from these combinations. A tentative model of stimulation of gonadal development by intersexual contact in pubertal fish was developed. Males stimulate ovarian development of females by both olfactory and tactile cues. In addition, males seem to enhance gonadal development of other males through olfactory stimulation via holding water. In contrast, females tended to inhibit male gonadal development, especially through tactile cues. It seems that although males are hampered by female tactile stimuli in their gonadal development and ability to stimulate male gonadal development, their ability to stimulate female gonadal development is not affected.

  10. Pubertal status associations with reward and threat sensitivities and subcortical brain volumes during adolescence.

    Science.gov (United States)

    Urošević, Snežana; Collins, Paul; Muetzel, Ryan; Lim, Kelvin O; Luciana, Monica

    2014-08-01

    Adolescence is characterized by complex developmental processes that impact behavior, biology, and social functioning. Two such adolescence-specific processes are puberty and increases in reward sensitivity. Relations between these processes are poorly understood. The present study focused on examining unique effects of puberty, age, and sex on reward and threat sensitivities and volumes of subcortical brain structures relevant for reward/threat processing in a healthy sample of 9-18year-olds. Unlike age, pubertal status had a significant unique positive relationship with reward sensitivity. In addition, there was a trend for adolescent females to exhibit higher threat sensitivity with more advanced pubertal development and higher reward and threat sensitivity with older age. Similarly, there were significant puberty by sex interaction effects on striatal volumes, i.e., left nucleus accumbens and right pallidum. The present pattern of results suggests that pubertal development, independent of chronological age, is uniquely associated with reward hypersensitivity and with structural differences in striatal regions implicated in reward processing.

  11. Pubertal assessment: a national survey of attitudes, knowledge and practices of the US pediatric trainees.

    Science.gov (United States)

    Khokhar, Aditi; Ravichandran, Yagnaram; Stefanov, Dimitre G; Perez-Colon, Sheila

    2017-07-06

    Background and objective Sex maturity rating (SMR), defines different levels of sexual maturity, based on the development of secondary sexual characteristics. Periodic assessment of pubertal maturation by physicians is crucial for timely identification of puberty-related disorders. With this pilot study, we aimed to assess the attitudes, knowledge and practices of pubertal assessment by current US pediatric trainees. Methods An anonymous online survey questionnaire was sent to categorical pediatric residents at different levels of training and pediatric chief residents across the US. Results We received responses from 2496 pediatric residents from all over the US. We found that 96% of trainees understand the importance of assessing SMR, 62% feel confident in assessing it and 55% feel comfortable assessing the need for an endocrinology referral. Only 33% of trainees performed external genital exams during all regular clinic visits while 26.9% never performed them during sick visits and 6% never assessed SMR during any of the patient visits. Higher levels of training and having completed an endocrinology rotation were associated with improvement in comfort level, practice and knowledge of trainees regarding pubertal assessment. Conclusion This study revealed that the current clinical practices of performing external genital exams and SMR among pediatric residents need improvement. Stronger reinforcement from continuity clinic preceptors and/or online and clinic based resources for SMR assessment for trainees may improve adherence to the recommended guidelines.

  12. Pubertal development in adolescents with menstrual disorders

    Directory of Open Access Journals (Sweden)

    Alberto Roteta Dorado

    2010-07-01

    Full Text Available Introduction: Abnormal uterine bleeding is the presence of an excessive and prolonged menstrual bleeding over several consecutive cycles. It is one of the first complaints in pediatric gynecology and is the most common cause dysfunctional uterine bleeding. Objective: To characterize adolescents with menstrual disorders attending gynecology clinic in child and adolescent onset of puberty. Method: A descriptive, longitudinal and prospective. Universe: 88 adolescents seen at the gynecology children and youth in the province of Cienfuegos with menstrual disorders in 2008. Sample: 64 patients with rhythm disturbances of the menstrual cycle and excessive bleeding. Procedure: During the first consultation was found in the following medical records: age, onset of puberty, age at menarche, breast development and pubic hair development. The data were processed by SPSS program and expressed as numbers and percentages. Results: 43.8% of the adolescents studied were between 14 and 16 years, 29.7% began puberty at age 9, 31.3% had their menarche at age 11, 46, 87% were in Tanner stage IV of breast development and 56.25% in Tanner stage IV for pubic hair. Conclusion: There were no alterations in pubertal development in adolescents with menstrual disorders studied.

  13. Effective Time Management

    OpenAIRE

    Wieprzycka, Agnieszka

    2013-01-01

    This paper presents the importance of time management, focusing on individuals. In subsequent parts of the paper, some of the most common obstacles of time management and ways of overcoming them are characterized. In the final part of the paper the emphasis is put on procrastination. Summing up, some of the author’s reflections are presented in this paper.

  14. The dynamics of bone structure development during pubertal growth.

    Science.gov (United States)

    Rauch, F

    2012-03-01

    The pubertal growth spurt is a time of rapid changes in bone length, mass and structure, followed by the cessation of longitudinal growth. The two best studied anatomical areas in this respect are the metaphyses and the diaphyses of peripheral long bones. A model is presented here in which the speed of longitudinal growth and the resulting age gradient in metaphyseal bone are key factors in explaining the high incidence of distal radius fractures during puberty. As growth in length accelerates, the age of the bone structural elements at a given distance to the growth plate decreases, leaving less time for cortical thickening through trabecular coalescence. This leads to a discrepancy between stagnant metaphyseal bone strength and increasing mechanical requirements in the case of accidents. In comparison to the metaphysis, diaphyseal bone develops more in line with the increasing mechanical requirements, presumably because the bone formation rates needed for diaphyseal growth in width are only a fraction of the apposition rates in the metaphysis. It remains largely unexplored how local and systemic signals are integrated to achieve site-specific changes in bone structure.

  15. Candidate gene expression in Bos indicus ovarian tissues: pre-pubertal and post-pubertal heifers in diestrus

    Directory of Open Access Journals (Sweden)

    Mayara Morena Del Cambre Amaral Weller

    2016-10-01

    Full Text Available Growth factors such as bone morphogenetic proteins 6, 7, 15 and two isoforms of transforming growth factor-beta (BMP6, BMP7, BMP15, TGFB1 and TGFB2 and insulin-like growth factor system act as local regulators of ovarian follicular development. To elucidate if these factors as well as others candidate genes such as estrogen receptor 1 (ESR1, growth differentiation factor 9 (GDF9, follicle stimulating hormone receptor (FSHR, luteinizing hormone receptor (LHR, bone morphogenetic protein receptor, type 2 (BMPR2, type 1 insulin-like growth factor receptor (IGFR1, and key steroidogenic enzymes cytochrome P450 aromatase and 3-β-hydroxysteroid dehydrogenase (CYP19A1 and HSD3B1 could modulate or influence diestrus on the onset of puberty in Brahman heifers, their ovarian mRNA expression was measured before and after puberty (luteal phase. Six post-pubertal (POST heifers were euthanized on the luteal phase of their second cycle, confirmed by corpus luteum observation, and six pre-pubertal (PRE heifers were euthanized in the same day. Quantitative real-time PCR analysis showed that the expression of FSHR, BMP7, CYP19A1, IGF1 and IGFR1 mRNA was greater in PRE heifers, when contrasted to POST heifers. The expression of LHR and HSD3B1 was lower in PRE heifers. Differential expression of ovarian genes could be associated with changes in follicular dynamics and different cell populations that have emerged as consequence of puberty and the luteal phase. The emerging hypothesis is that BMP7 and IGF1 are co-expressed and may modulate the expression of FSHR, LHR and IGFR1 and CYP19A1. BMP7 could influence the down-regulation of LHR and up-regulation of FSHR and CYP19A1, which mediates the follicular dynamics in heifer ovaries. Up-regulation of IGF1 expression pre-puberty, compared to post-puberty diestrus, correlates with increased levels FSHR and CYP19A1. Thus, BMP7 and IGF1 may play synergic roles and were predicted to interact, from the expression data (P = 0

  16. Two leptin genes and a leptin receptor gene of female chub mackerel (Scomber japonicus): Molecular cloning, tissue distribution and expression in different obesity indices and pubertal stages.

    Science.gov (United States)

    Ohga, Hirofumi; Matsumori, Kojiro; Kodama, Ryoko; Kitano, Hajime; Nagano, Naoki; Yamaguchi, Akihiko; Matsuyama, Michiya

    2015-10-01

    Leptin is a hormone produced by fat cells that regulates the amount of fat stored in the body and conveys nutritional status to the reproductive axis in mammals. In the present study we identified two subtypes of leptin genes (lepa and lepb) and a leptin receptor gene (lepr) from chub mackerel (Scomber japonicus) and there gene expression under different feeding conditions (control and high-feed) and pubertal development stages was analyzed using quantitative real-time PCR. The protein lengths of LepA, LepB and LepR were 161 amino acids (aa), 163 aa and 1149 aa, respectively and both leptin subtypes shared only 15% similarity in aa sequences. In pubertal females, lepa was expressed in the brain, pituitary gland, liver, adipose tissue and ovary; however, in adult (gonadal maturation after the second in the life) females, lepa was expressed only in the liver. lepb was expressed primarily in the brain of all fish tested and was expressed strongly in the adipose tissue of adults. lepr was characterized by expression in the pituitary. The high-feed group showed a high conditioning factor level; unexpectedly, hepatic lepa and brain lepr were significantly more weakly expressed compared with the control-feed group. Furthermore, the expression levels of lepa, lepb and lepr genes showed no significant differences between pre-pubertal and post-pubertal fish. On the other hand, pituitary fshβ and lhβ showed no significant differences between different feeding groups of pre-pubertal fish. In contrast, fshβ and lhβ expressed abundantly in the post-pubertal fish of control feed group. Based on these results, whether leptin plays an important role in the nutritional status and pubertal onset of chub mackerel remains unknown.

  17. Skin surface lipid composition, acne, pubertal development, and urinary excretion of testosterone and 17-ketosteroids in children.

    Science.gov (United States)

    Pochi, P E; Strauss, J S; Downing, D T

    1977-11-01

    Fifty-two children, age 5-10, from acne-prone families, were studied for a period of 1 year to examine the interrelationship between sebum, acne, pubertal development, and urinary steroid excretion. In each of the subjects, 30 boys and 22 girls, the composition of forehead skin lipid was determined 4 times yearly by thin-layer chromatography, with measurement of triglycerides, diglycerides, free fatty acids, wax esters, squalene, cholesterol, and cholesterol esters. Twice yearly, examination was made of the presence or absence of acne, pubertal maturation and the 24-hour urinary excretion of testosterone as determined by radioimmunnoassay, and of total 17-ketosteroids, dehydroepiandrosterone, androsterone, and etiocholanolone, as determined by paper chromatography. The relative amount of sebaceous lipids was positively correlated with age of the subjects (wax esters p less than .001, squalene p less than .05), as was the triglyceride-diglyceride component (p less than .05). No significant correlation was seen with the fatty acids. Acne, primarily comedonal, occurred in 27/52 subjects (15 girls, 12 boys) and was associated with higher sebum values. One-half of the children with acne had no signs of pubertal development. A significantly positive correlation was observed between the relative amount of sebaceous lipid and the urinary excretion of 17-ketosteroids, androsterone, and etiocholanolone in both sexes, and of testosterone and dehydroepiandrosterone in boys. The development of acne in children is an early pubertal event, often evident before other signs of pubertal maturation, and it is associated with an increase in sebum and in the urinary excretion of androgenic steroids.

  18. Xenoestrogens diethylstilbestrol and zearalenone negatively influence pubertal rat's testis.

    Directory of Open Access Journals (Sweden)

    Katarzyna Marchlewska

    2010-01-01

    Full Text Available The aim of this study was to assess the impact of xenoestrogens: diethylstilbestrol (DES and zearalenone (ZEA on rat's pubertal testis and to compare it with the effect of natural estrogen - 17beta-estradiol (E. Male Wistar rats were daily, subcutaneously injected at 5th-15th postnatal days (p.d. with E (1.25 or 12.5 mug or DES (1.25 or 12.5 mug or ZEA (4 or 40 mug or vehicle. At 16th p.d. testes were dissected, weighted, and paraffin embedded. Following parameters were assessed: diameter and length of seminiferous tubule, numbers of spermatogonia A+intermediate+B (A/In/B, preleptotene spermatocytes (PL, leptotene+zygotene+pachytene spermatocytes (L/Z/PA and Sertoli cells per testis. Testes weight, seminiferous tubule diameter and length were decreased by both doses of E, DES and ZEA. DES effect was the strongest, but its influence on testis weight and seminiferous tubule length, on the contrary to E and ZEA, was not dose-dependent. Similarly, DES in both doses had the most severe negative impact on the number of germ and Sertoli cells. The negative influence of E on germ cells was less pronounced. The negative effect of ZEA was seen only after administration of the higher dose on spermatogonia number, while DES and E decreased A/In/B number more evidently. Sertoli cell number were decreased after both doses of E. ZEA40 decreased Sertoli cell number while ZEA4 had no effect. Conclusion: exposure of prepubertal male rat to DES has the strongest detrimental effect on the developing testis in comparison to E and ZEA. Both, E and DES, decreased number of germ and Sertoli cells, diminished seminiferous tubule diameter, length and testis weight. ZEA had much more weaker effect than the potent estrogens.

  19. Serum inhibin B in healthy pubertal and adolescent boys

    DEFF Research Database (Denmark)

    Andersson, A M; Juul, A; Petersen, J H;

    1997-01-01

    Inhibin B levels were measured in serum from 400 healthy Danish prepubertal, pubertal, and adolescent males, aged 6-20 yr, in a cross-sectional study using a recently developed immunoassay that is specific for inhibin B, the physiologically important inhibin form in men. In addition, serum levels...

  20. Validity of self-assessment of pubertal maturation

    DEFF Research Database (Denmark)

    Rasmussen, Anna; Wohlfahrt-Veje, Christine; Tefre de Renzy-Martin, Katrine;

    2015-01-01

    BACKGROUND AND OBJECTIVES: Studies of adolescents often use self-assessment of pubertal maturation, the reliability of which has shown conflicting results. We aimed to examine the reliability of child and parent assessments of healthy boys and girls. METHODS: A total of 898 children (418 girls, 480...

  1. Oxidative stress and the enzyme system of aldehyde catabolism in the muscle mitochondria of immobilized pubertal rats

    Directory of Open Access Journals (Sweden)

    Amjad Hamdallah

    2014-12-01

    Full Text Available The aim of the work is to find out peculiarities in manifestation of oxidative stress and to determine activity of enzymes, responsible for utilization of endogenous aldehydes in the mitochondrial fraction of the skeletal (femoral muscle in pubertal rats during immobilization stress. Our study has shown that differently directed changes in the activity of mitochondrial aldehyde dehydrogenases and aldehyde reductases occur in the pubertal immobilized rats, that limits the catabolism effectiveness as regards carbonyl products of free radical oxidation in the muscle cells. Corroboration of the effect under consideration is an increased level of protein free radical oxidation products in the mitochondria of the skeletal muscle. On the basis of the obtained data the authors draw a conclusion about an increased sensitivity of the skeletal muscle to the oxidative stress impact due to modulation in the state of enzyme system, responsible for utilization of endogenous aldehydes in the mitochondria.

  2. The association of peripubertal serum concentrations of organochlorine chemicals and blood lead with growth and pubertal development in a longitudinal cohort of boys: a review of published results from the Russian Children's Study.

    Science.gov (United States)

    Sergeyev, Oleg; Burns, Jane S; Williams, Paige L; Korrick, Susan A; Lee, Mary M; Revich, Boris; Hauser, Russ

    2017-02-23

    Organochlorine chemicals and lead are environmental exposures that have endocrine disrupting properties (EDCs) which interfere with many aspects of hormone action. Childhood and adolescence are windows of susceptibility for adverse health effects of EDCs. Our ongoing study, the Russian Children's Study (RCS), is one of the few longitudinal studies investigating the impact of EDCs on growth and puberty in boys. It is conducted in the historically contaminated city of Chapaevsk, in the Samara region. The study focuses on evaluating the associations of persistent organochlorine chemicals and lead with growth and pubertal timing. At enrollment in 2003-2005, we collected blood from 516 boys at ages 8-9 years to measure dioxins, furans, polychlorinated biphenyls (PCBs), chlorinated pesticides and lead. At enrollment and at annual visits through the ages of 18-19 years, a physician performed physical examinations that included pubertal staging and testicular volume measurements. We review the history of Chapaevsk as a research site and summarize published RCS data on the association of peripubertal serum concentrations of organochlorines and blood lead levels with growth, pubertal onset and sexual maturity. Overall, we found that persistent organochlorines and lead negatively affected growth during puberty. Our results also suggest that total toxic equivalents (TEQs), dioxin-like compounds, organochlorine pesticides and lead may delay, while nondioxin-like-PCBs may advance, the timing of male puberty. These findings promoted remediation programs in Chapaevsk, with improvement in health indicators, resulting in Chapaevsk being designated a member of the World Health Organization (WHO) network "Healthy Cities" in 2015.

  3. Timely and Effective Care - State

    Data.gov (United States)

    U.S. Department of Health & Human Services — Timely and Effective Care measures - state data. This data set includes state-level data for measures of heart attack care, heart failure care, pneumonia care,...

  4. Timely and Effective Care - Hospital

    Data.gov (United States)

    U.S. Department of Health & Human Services — Timely and Effective Care measures - provider data. This data set includes provider-level data for measures of heart attack care, heart failure care, pneumonia care,...

  5. Timely and Effective Care - National

    Data.gov (United States)

    U.S. Department of Health & Human Services — Timely and Effective Care measures - national data. This data set includes national-level data for measures of heart attack care, heart failure care, pneumonia care,...

  6. Excess of leptin inhibits hypothalamic KiSS-1 expression in pubertal mice

    Directory of Open Access Journals (Sweden)

    Sung Yeon Ahn

    2012-09-01

    Full Text Available &lt;B&gt;Purpose:&lt;/B&gt; Leptin has been considered a link between metabolic state and reproductive activity. Defective reproductive function can occur in leptin-deficient and leptin-excessive conditions. The aim of this study was to examine the effects of centrally injected leptin on the hypothalamic &lt;I&gt;KiSS-1&lt;/I&gt; system in relation to gonadotropin-releasing hormone (GnRH action in the initial stage of puberty. &lt;B&gt;Methods:&lt;/B&gt; Leptin (1 μg was injected directly into the ventricle of pubertal female mice. The resultant gene expressions of hypothalamic &lt;I&gt;GnRH&lt;/I&gt; and &lt;I&gt;KiSS-1&lt;/I&gt; and pituitary LH, 2 and 4 hours after injection, were compared with those of saline-injected control mice. The changes in the gene expressions after blocking the GnRH action were also analyzed. &lt;B&gt;Results:&lt;/B&gt; The basal expression levels of &lt;I&gt;KiSS-1&lt;/I&gt;, GnRH, and LH were significantly higher in the pubertal mice than in the prepubertal mice. The 1-μg leptin dose significantly decreased the mRNA expression levels of &lt;I&gt;KiSS-1&lt;/I&gt;, GnRH, and LH in the pubertal mice. A &lt;I&gt;GnRH&lt;/I&gt; antagonist significantly increased the &lt;I&gt;KiSS-1&lt;/I&gt; and GnRH mRNA expression levels, and the additional leptin injection decreased the gene expression levels compared with those in the control group. &lt;B&gt;Conclusion:&lt;/B&gt; The excess leptin might have suppressed the central reproductive axis in the pubertal mice by inhibiting the &lt;I&gt;KiSS-1&lt;/I&gt; expression, and this mechanism is independent of the GnRH-LHestradiol feedback loop.

  7. Pubertal and adult windows of susceptibility to a high animal fat diet in Trp53-null mammary tumorigenesis.

    Science.gov (United States)

    Zhu, Yirong; Aupperlee, Mark D; Zhao, Yong; Tan, Ying Siow; Kirk, Erin L; Sun, Xuezheng; Troester, Melissa A; Schwartz, Richard C; Haslam, Sandra Z

    2016-12-13

    Premenopausal breast cancer is associated with increased animal fat consumption among normal weight, but not overweight women (Farvid et al., 2014). Our previous findings in obesity-resistant BALB/c mice similarly showed promotion of carcinogen-induced mammary tumorigenesis by a diet high in saturated animal fat (HFD). This effect was specific to pubertal versus adult HFD. This study identifies the effects of HFD during puberty versus adulthood in Trp53-null transplant BALB/c mice and investigates its mechanism of enhancing tumorigenesis. Either pubertal or adult HFD is sufficient to increase incidence of Trp53-null mammary tumors. Puberty-restricted HFD exposure promoted tumor cell proliferation, increased angiogenesis, and increased recruitment of total and M2 macrophages in epithelial tumors. Adult-restricted exposure to HFD similarly increased proliferation, angiogenesis, recruitment of total and M2 macrophages, and additionally reduced apoptosis. Adult HFD also increased incidence of spindle cell carcinomas resembling claudin-low breast cancer, and thus adult HFD in the Trp53-null transplantation system may be a useful model for human claudin low breast cancer. Importantly, these results on Trp53-null and our prior studies on DMBA-induced mammary tumorigenesis demonstrate a pubertal window of susceptibility to the promotional effects of HFD, indicating the potential of early life dietary intervention to reduce breast cancer risk.

  8. Effects of Prenatal Exposure to a Low Dose Atrazine Metabolite Mixture on pubertal timing and prostrate Development of Male Long Evans Rats.

    Science.gov (United States)

    The present study examines the postnatal reproductive development of male rats following prenatal exposure to an atrazine metabolite mixture (AMM) consisting of the herbicide atrazine and its environmental metabolites diaminochlorotriazine, hydroxyatrazine, deethylatrazine, and d...

  9. Effects of Prenatal Exposure to a Low Dose Atrazine Metabolite Mixture on pubertal timing and prostrate Development of Male Long Evans Rats.

    Science.gov (United States)

    The present study examines the postnatal reproductive development of male rats following prenatal exposure to an atrazine metabolite mixture (AMM) consisting of the herbicide atrazine and its environmental metabolites diaminochlorotriazine, hydroxyatrazine, deethylatrazine, and d...

  10. Female Pubertal Timing and Problem Behaviour: The Role of Culture

    Science.gov (United States)

    Skoog, Therese; Stattin, Hakan; Ruiselova, Zdena; Ozdemir, Metin

    2013-01-01

    We tested the peer-socialization/contextual-amplification explanation for the link between early female puberty and problem behaviour. We propose that in cultures with high tolerance for adolescent heterosexual involvement, early puberty should be linked with problem behaviour--not in other cultures. We compared girls in two cultures (Slovakia and…

  11. Female Pubertal Timing and Problem Behaviour: The Role of Culture

    Science.gov (United States)

    Skoog, Therese; Stattin, Hakan; Ruiselova, Zdena; Ozdemir, Metin

    2013-01-01

    We tested the peer-socialization/contextual-amplification explanation for the link between early female puberty and problem behaviour. We propose that in cultures with high tolerance for adolescent heterosexual involvement, early puberty should be linked with problem behaviour--not in other cultures. We compared girls in two cultures (Slovakia and…

  12. Prevalence of acne in primary school children and the relationship of acne with pubertal maturation

    OpenAIRE

    Hilal Kaya Erdoğan; İlknur Kıvanç Altunay; Serap Turan

    2014-01-01

    Background and Design: Although acne vulgaris is generally regarded as a disease of adolescence period, it can occur in infancy, early childhood and prepubertal period. Acne may emerge as the first sign of pubertal maturation. In our study, we aimed to determine the acne prevalence in primary school children, then, evaluate the pubertal signs in those children; examine the correlation of the presence and severity of acne with pubertal signs, and finally, revise the concept of prepubertal a...

  13. Timing effects on first marriage

    DEFF Research Database (Denmark)

    Schoen, Robert; Canudas-Romo, Vladimir

    2005-01-01

    Recent substantial declines in first marriage in Western countries have been accompanied by increases in the average age at first marriage. Since the period proportion ever marrying, PEM, is sensitive to cohort tempo changes, the recent fall in the PEM may simply reflect cohort delays in marriage....... The importance of timing factors is examined in the light of twentieth-century experience of first marriage in England and Wales and the USA. Using a variant of the Timing Index developed in research on fertility, we measure cohort timing effects for marriage and calculate an adjusted PEM. After examining...

  14. EFFECTS OF PUBERTAL ALIMENTARY OBESITY ON REPRODUCTIVE ORGAN DEVELOPMENT AND FERTILITY OF MALE RATS%青春期营养性肥胖对雄性大鼠生殖器官发育及生育能力的影响

    Institute of Scientific and Technical Information of China (English)

    张璇; 张玉敏; 裴秀丛; 马明月; 段志文

    2016-01-01

    目的:研究青春期营养性肥胖对雄性大鼠生殖器官发育及生殖能力的影响。方法使用高脂高能量饲料喂饲4周龄Wistar雄性大鼠,制作青春期营养性肥胖模型,饲喂8周后检查大鼠生殖器官发育情况并进行病理组织学检测,采用酶联免疫吸附试验(ELISA )法检测血清睾酮、雌二醇含量,计数精子总数及活动率;按1︰2比例与雌鼠合笼1周,检测雄鼠交配指数和生育指数,并对胎鼠发育情况进行检查。结果模型组大鼠睾丸脏器系数明显低于对照组(P<0.05),光镜下发现模型组生精小管管壁变薄、细胞数减少、细胞排列紊乱;血清睾酮含量明显低于对照组(P<0.01);生育指数低于对照组(P<0.05);二组精子总数、活动率、血清雌二醇含量、交配指数、胎鼠各项发育指标比较差异均无统计学意义(P>0.05)。结论肥胖可影响大鼠睾丸发育,致血清睾酮含量降低、生育指数下降;但未观察到对胎鼠发育的影响。%Objective To observe the effects of pubertal alimentary obesity on reproductive organ develop‐ment and fertility of male rats .Methods The pubertal alimentary obesity model was made by feeding 4 weeks old male Wistar rats with high fat feeds ,then the development of reproductive organ was checked , pathological detection was done ,serum testosterone and estradiol concentration was tested by ELISA es‐say ,the total number of sperm and activity rate was counted .The copulation and fertility index of male rats was detected and the development of fetal rats was measured after mating of the male with female(propor‐tion 1∶2) for 1 week .Results The organ coefficient of testis in obesity group was significantly lower than that in the control group (P<0 .05) ,light microscopy examination founds that seminiferous tubule wall be‐come thinner ,number of cells reduced and disorder in cells arrangement was

  15. Diagnostic Markers of Primary Infertility in Women of Reproductive Age with Hypothalamic Dysfunction in the Pubertal Period

    Directory of Open Access Journals (Sweden)

    Irina V. Zhukovets

    2017-09-01

    Full Text Available The aim of the study was to assess fertility in women of reproductive age with hypothalamic dysfunction (HD in the pubertal period and to determine the diagnostic significance of pro-inflammatory (TNF-α and IL-1β, anti-inflammatory cytokine (IL-10 and NF-kB activity in the diagnosis of primary infertility in these women. Materials and Methods: Fertility was assessed in 86 women of reproductive age with HD in the pubertal period. A comparative characteristic of fertile women (Group 1, n=46 and primary infertility women (Group 2, n=21 with HD in the pubertal period was performed. FPG and FPI were determined after 8 to 12 hours of fasting. Serum IRI concentrations were measured using an ELISA kit. The levels of TNF-α, IL-1β and IL-10 were determined in the venous blood serum after a 12-hour fasting, as well as in UA on the 21st day of the menstrual cycle using ELISA kits. The activity of NF-kB was determined in UA on the 21st day of the menstrual cycle using an enzyme immunoassay kit. Results: BMI in Group 1 was significantly lower than in Group 2: 22.63±2.68 kg/m2 versus 27.05±4.03kg/m2 (p=0.000. WC in women of Group 1 was 66.11±5.66cm versus 78.52±10.54cm in Group 2 (p = 0.000; WC >80cm was found in 2(4.4% and 14(66.7% women, respectively (p = 0.000. The average levels of FPG and FPI were significantly higher in Group 2. Serum levels of TNF-α and IL-1β in Group 2 were significantly higher than in Group 1. The serum level of anti-inflammatory cytokine IL-10 was significantly lower in Group 2; accordingly, the TNF-α/IL-10 ratio in Group 2 was 1.8 times higher than in Group 1. The IL-1β level in UA (P=0.000 and the TNF-α/IL-10 ratio (P=0.02 were significantly higher in women of Group 2 than Group 1, which indicated the pronounced inflammatory effects of TNF-α in the endometrium. Imbalance in the production of pro-inflammatory and anti-inflammatory factors indicated the activation of the Th-1 immune response with the formation of the

  16. Association between CYP19A1 genotype and pubertal sagittal jaw growth

    Science.gov (United States)

    He, Shushu; Hartsfield, James K.; Guo, Yujiao; Cao, Yang; Wang, Si; Chen, Song

    2016-01-01

    Introduction Sagittal jaw growth is influenced during puberty by a ratio of androgens and estrogens. The CYP19A1 (formerly CYP19) gene encodes the cytochrome P450 enzyme aromatase (estrogen synthetase), which converts testosterone to estrogen. Genetic variations including single nucleotide polymorphisms might regulate CYP19A1 gene expression or the function of the aromatase protein and thus influence sagittal jaw growth. Methods The annual sagittal jaw growth in 92 pubertal orthodontic patients was determined by using pretreatment and posttreatment cephalometric radiographs. Single nucleotide polymorphisms rs2470144 and rs2445761 were genotyped and haplotypes constructed. Associations between genotypes or haplotypes and the annual sagittal growth were estimated by using JMP (version 9.0; SAS Institute, Cary, NC). Results Two single nucleotide polymorphisms were significantly associated with average differences in annual sagittal jaw growth in boys. Haplotype analysis demonstrated that haplotypes Trs2470144Trs2445761 and Crs2470144Trs2445761 had significant effects on annual sagittal maxillary growth and on mandibular growth in boys. No association was found in girls. Conclusions A quantitative trait locus that influences male pubertal sagittal jaw growth might exist in the CYP19A1 gene, and single nucleotide polymorphisms rs2470144 and rs2445761 might be inside this quantitative trait locus or be linked to it. PMID:23116507

  17. Loss of vitamin D receptor signaling from the mammary epithelium or adipose tissue alters pubertal glandular development.

    Science.gov (United States)

    Johnson, Abby L; Zinser, Glendon M; Waltz, Susan E

    2014-10-15

    Vitamin D₃ receptor (VDR) signaling within the mammary gland regulates various postnatal stages of glandular development, including puberty, pregnancy, involution, and tumorigenesis. Previous studies have shown that vitamin D₃ treatment induces cell-autonomous growth inhibition and differentiation of mammary epithelial cells in culture. Furthermore, mammary adipose tissue serves as a depot for vitamin D₃ storage, and both epithelial cells and adipocytes are capable of bioactivating vitamin D₃. Despite the pervasiveness of VDR in mammary tissue, individual contributions of epithelial cells and adipocytes, as well as the VDR-regulated cross-talk between these two cell types during pubertal mammary development, have yet to be investigated. To assess the cell-type specific effect of VDR signaling during pubertal mammary development, novel mouse models with mammary epithelial- or adipocyte-specific loss of VDR were generated. Interestingly, loss of VDR in either cellular compartment accelerated ductal morphogenesis with increased epithelial cell proliferation and decreased apoptosis within terminal end buds. Conversely, VDR signaling specifically in the mammary epithelium modulated hormone-induced alveolar growth, as ablation of VDR in this cell type resulted in precocious alveolar development. In examining cellular cross-talk ex vivo, we show that ligand-dependent VDR signaling in adipocytes significantly inhibits mammary epithelial cell growth in part through the vitamin D₃-dependent production of the cytokine IL-6. Collectively, these studies delineate independent roles for vitamin D₃-dependent VDR signaling in mammary adipocytes and epithelial cells in controlling pubertal mammary gland development.

  18. Prevalence of acne in primary school children and the relationship of acne with pubertal maturation

    Directory of Open Access Journals (Sweden)

    Hilal Kaya Erdoğan

    2014-12-01

    Full Text Available Background and Design: Although acne vulgaris is generally regarded as a disease of adolescence period, it can occur in infancy, early childhood and prepubertal period. Acne may emerge as the first sign of pubertal maturation. In our study, we aimed to determine the acne prevalence in primary school children, then, evaluate the pubertal signs in those children; examine the correlation of the presence and severity of acne with pubertal signs, and finally, revise the concept of prepubertal acne. Materials and Methods: A thousand students from 2 schools in Istanbul were included in the study. Age, gender, and the presence, localization and severity of acne were recorded. Acne severity was evaluated using the Orfanos-Gollnick Acne Grading System while a validated self evaluation form which had been developed by Morris and Udry was used to evaluate pubertal stage. Data were evaluated statistically. Results: Five hundred and thirty-four male and 466 female primary school children, with an age range of 7 to 11, were included in the study. Acne was determined in 11.5% of the students. 20% of girls and 4% of boys had acne. Comparing acne presence and age, the average age was higher in group with acne than those with no acne. The mean age of children with grade 1 acne was lower than those with grade 2 acne. All the students with acne had mid-facial acne. Comparing acne presence and pubertal symptoms, the rate of the presence of acne was higher in pubertal girls. No acne was observed in prepubertal boys. Evaluating acne severity and pubertal signs, the difference between prepubertal and pubertal girls was not significant. Comparing acne and telarche stages, the group without acne had lower telarche rates. Comparing acne and pubertal stages, children with acne had advanced puberty. Conclusion: Our study denotes that acne prevalence is related to pubertal maturation and age; while it does not support the hypothesis that acne is the first sign of pubertal

  19. Giant pubertal prolactinoma: Complete resolution following short ...

    African Journals Online (AJOL)

    2016-04-06

    Apr 6, 2016 ... disappeared in a short time with cabergoline treatment. Key words: ... stature, and delayed development of his secondary sex characteristics. .... Leong KS, Foy PM, Swift AC, Atkin SL, Hadden DR, MacFarlane IA. CSF.

  20. Dissipative Effect and Tunneling Time

    Directory of Open Access Journals (Sweden)

    Samyadeb Bhattacharya

    2011-01-01

    Full Text Available The quantum Langevin equation has been studied for dissipative system using the approach of Ford et al. Here, we have considered the inverted harmonic oscillator potential and calculated the effect of dissipation on tunneling time, group delay, and the self-interference term. A critical value of the friction coefficient has been determined for which the self-interference term vanishes. This approach sheds new light on understanding the ion transport at nanoscale.

  1. Semen characteristics in pubertal boys. I. Semen quality after first ejaculation.

    Science.gov (United States)

    Janczewski, Z; Bablok, L

    1985-01-01

    Semen specimens from 134 pubertal boys were examined, and some 274 assays were made. An analysis of the biological quality of semen in relation to the period of time after first ejaculation brings high values of statistical dependence of the volume of semen, its liquefaction, spermatozoal concentration, percentage of morphologically normal forms of spermatozoa, and normal spermatozoal motility on the period of time after first ejaculation. Normal figures for semen volume, semen liquefaction, spermatozoal concentration, and morphology are observed 12-14 months after first ejaculation. The percentage of normally motile spermatozoa becomes standard 21-23 months after first ejaculation. There were changes in semen characteristics from azoospermia through cryptozoospermia, oligozoospermia, and asthenozoospermia to normospermia. Azoospermia dominates until the fifth month after the first ejaculation, oligozoospermia from the sixth to the eleventh month, asthenozoospermia from the twelfth to the twentieth month, and normospermia from the twenty-first month.

  2. Prenatal androgen excess programs metabolic derangements in pubertal female rats.

    Science.gov (United States)

    Yan, Xiaonan; Dai, Xiaonan; Wang, Jing; Zhao, Nannan; Cui, Yugui; Liu, Jiayin

    2013-04-01

    Owing to the heterogeneity in the clinical symptoms of polycystic ovary syndrome (PCOS), the early pathophysiological mechanisms of PCOS remain unclear. Clinical, experimental, and genetic evidence supports an interaction between genetic susceptibility and the influence of maternal environment in the pathogenesis of PCOS. To determine whether prenatal androgen exposure induced PCOS-related metabolic derangements during pubertal development, we administrated 5α-dihydrotestosterone (DHT) in pregnant rats and observed their female offspring from postnatal 4 to 8 weeks. The prenatally androgenized (PNA) rats exhibited more numerous total follicles, cystic follicles, and atretic follicles than the controls. Fasting glucose, insulin, leptin levels, and homeostatic model assessment for insulin resistance were elevated in the PNA rats at the age of 5-8 weeks. Following intraperitoneal glucose tolerance tests, glucose and insulin levels did not differ between two groups; however, the PNA rats showed significantly higher 30- and 60-min glucose levels than the controls after insulin stimulation during 5-8 weeks. In addition, prenatal DHT treatment significantly decreased insulin-stimulated phosphorylation of AKT in the skeletal muscles of 6-week-old PNA rats. The abundance of IR substrate 1 (IRS1) and IRS2 was decreased in the skeletal muscles and liver after stimulation with insulin in the PNA group, whereas phosphorylation of insulin-signaling proteins was unaltered in the adipose tissue. These findings validate the contribution of prenatal androgen excess to metabolic derangements in pubertal female rats, and the impaired insulin signaling through IRS and AKT may result in the peripheral insulin resistance during pubertal development.

  3. Betamethasone cream for the treatment of pre-pubertal labial adhesions.

    Science.gov (United States)

    Myers, Jeremy B; Sorensen, Carsten M; Wisner, Benjamin P; Furness, Peter D; Passamaneck, Michelle; Koyle, Martin A

    2006-12-01

    We evaluated the efficacy of 0.05% betamethasone cream for the treatment of pre-pubertal labial adhesions. We retrospectively reviewed the records of 19 children with labial adhesions who were treated with betamethasone cream from 6/2001 to 3/2003. Children were treated with 1 to 3 courses of twice-daily 0.05% betamethasone cream for 4 to 6 weeks. Successful lysis of adhesions was assessed by clinical exam or parental phone contact and outcomes were defined as: (1) success--complete separation of labia, (2) partial success--greater than 75% separation, (3) progression to surgical lysis, and (4) lost to follow-up. Nineteen patients with an average age of 58 months (range 12 to 132 months) were treated. Four of the 19 patients had never been treated previously and 1 had been treated previously with surgical lysis of adhesions only. Fourteen of the 19 patients had been previously treated with conjugated estrogen (Premarin) cream. Two of these fourteen patients had also undergone surgical lysis of adhesions. Severity of adhesions ranged from 33% to 99% labial closure. Betamethasone cream was successful in treating 13/19 (68%) pre-pubertal labial adhesions. Eleven (85%) of these 13 patients had complete resolution of labial adhesions with 1 course of treatment, 1 (7.5%) had resolution with 2 courses of treatment and 1 (7.5%) had resolution with 3 courses of treatment. One patient had a partial success with 3 courses of betamethasone cream. Two (11%) patients underwent surgical lysis of adhesion after 1 and 2 courses of betamethasone cream respectively. Three (16%) patients were lost to follow-up. Average follow-up was 7 months (range 1-24 months). No adverse outcomes or untoward effects were noted in any of the patients treated. Betamethasone 0.05% cream appears to be a safe and effective treatment of pre-pubertal labial adhesions as primary therapy or in patients that have failed previous therapies and it may avoid the undesirable side effects of breast budding and

  4. The Initiation of Dating in Adolescence : The Effect of Parental Divorce. The TRAILS Study

    NARCIS (Netherlands)

    Ivanova, Katya; Mills, Melinda; Veenstra, Rene

    2011-01-01

    This study examined the effect of parental divorce on the time it took adolescents to initiate their first romantic relationships. Individual differences in temperament and pubertal development and the age of the adolescent at the time of divorce were also taken into account. Hypotheses were tested

  5. The Initiation of Dating in Adolescence: The Effect of Parental Divorce. The TRAILS Study

    Science.gov (United States)

    Ivanova, Katya; Mills, Melinda; Veenstra, Rene

    2011-01-01

    This study examined the effect of parental divorce on the time it took adolescents to initiate their first romantic relationships. Individual differences in temperament and pubertal development and the age of the adolescent at the time of divorce were also taken into account. Hypotheses were tested using event history analysis with a sample of…

  6. Relationships between urinary biomarkers of phytoestrogens, phthalates, phenols, and pubertal stages in girls.

    Science.gov (United States)

    Chakraborty, Tandra R; Alicea, Eilliut; Chakraborty, Sanjoy

    2012-01-01

    Phytoestrogens, phthalates, and phenols are estrogen-disrupting chemicals that have a pronounced effect at puberty. They are exogenous chemicals that are either plant-derived or man-made, and can alter the functions of the endocrine system and cause various health defects by interfering with the synthesis, metabolism, binding, or cellular responses of natural estrogens. Phytoestrogens, phthalates, and phenols are some of the potent estrogens detectable in urine. Phytoestrogens are plant-derived xenestrogens found in a wide variety of food products, like soy-based food, beverages, several fruits, and vegetables. Exposure to phytoestrogens can delay breast development and further lead to precocious puberty. The effect of phytoestrogens is mediated through estrogen receptors α and β or by binding with early immediate genes, such as jun and fos. Phthalates are multifunctional synthetic chemicals used in plastics, polyvinyl chloride products, cosmetics, hair spray, and children's toys. Phthalates have been shown to cause defeminization, thelarche, precocious puberty, and an increase in breast and pubic hair in pubertal girls. However, reports are also available that show no association of phthalates with precocious puberty in girls. Phthalates can act through a receptor-mediated signaling pathway or affect the production of luteinizing hormone and follicle-stimulating hormone that has a direct effect on estrogen formation. Phenols like bisphenol A are industrial chemicals used mainly in the manufacture of polycarbonates and plastic materials. Bisphenol A has been shown to cause precocious puberty and earlier menarche in pubertal girls. Reports suggest that the neurotoxic effect of bisphenol A can be mediated either by competing with estradiol for binding with estrogen receptors or via the ERK/NK-kappa or ERRγ pathway. This review demonstrates the effects of phytoestrogens, phthalates, and phenols on the development of girls during puberty.

  7. Granular Vulvovaginitis Syndrome in Nelore pubertal and post pubertal replacement heifers under tropical conditions: role of Mycoplasma spp., Ureaplasma diversum and BHV-1.

    Science.gov (United States)

    Gambarini, M L; Kunz, T L; Oliveira Filho, B D; Porto, R N G; Oliveira, C M G; Brito, W M E D; Viu, M A O

    2009-10-01

    In order to determine the role of Mycoplasma spp, Ureaplasma diversum and BHV-1 as causal agents of Granular Vulvovaginitis Syndrome in Nelore heifers raised under tropical conditions and based on the hypothesis that stressful conditions during puberty or breeding season would be a determinant factor for the infection, 340 heifers not vaccinated against BHV-1 were divided in Post-pubertal, in the beginning of the first breeding season, and Pubertal heifers. The vaginal lesion score (VLS) Grade 1 to 4 was giving according to lesion area and severity. Vaginal mucus was used to isolate Mycoplasma spp., Ureaplasma diversum and BHV-1. The predominant VLS was 2. No sample was positive for BHV-1; 48% were positive for Mycoplasma spp., Ureaplasma diversum, or both, with predominance of Ureaplasma diversum. Serum neutralization for BHV-1 showed more positive animals in pubertal group (23%); 3 of the paired sera demonstrated seroconversion. These data indicated that post-pubertal and pubertal Nelore heifers raised under extensive conditions are more susceptible to Mycoplasma spp. and Ureaplasma diversum. The hypothesis that the stress of pubertal period could lead to an acute vaginal infection by HBV-1 was not proofed.

  8. Physical Stress may Result in Growth Suppression and Pubertal Delay in Working Boys

    Directory of Open Access Journals (Sweden)

    Muhammad Irfan

    2012-01-01

    Full Text Available Child labour is an immense problem in Pakistan. As labour boys are put under persistent/severe physical stress, we hypothesised, that it may result in higher levels of cortisol and exhaust glycogen, fats and protein. Depletion of fats may result in lower body weight, and insufficient leptin concentrations could excite gonadotropic releasing hormone (GnRH at normal time of puberty in working boys. Moreover, lower testosterone levels in working boys, due to delayed puberty, may result in suppression of somatotropic axis. Short/weak stature and failure of onset of puberty may cause poor performance, inferiority complex and psychological disorders. Therefore, the present study is designed to find out the timing of onset of puberty in working boys. The study will include 10–18 years of working boys as case and non-working boys of the same age group as control. Working boys will be labour boys, while the control group will not be involved in physical work. A questionnaire will be used to record socioeconomic status, major diseases, nutritional status, type and duration of work and family history of puberty, growth and obesity of subjects. Boys with familial history of pubertal delay, obesity, malnutrition, mental disorders, haematological diseases and severe/chronic diseases will be excluded. The intensity of physical working stress will be determined by a grading scale. The anthropometric data including height, weight, body mass index (BMI, bone age and tests of adiposity will be collected from subjects. The stages of pubertal onset will be determined by Tanner staging. Serum concentrations of hormones of growth, thyroid, adrenal, brain–gut and gonadal axis will be determined in non-working and working boys. Physical and hormonal tests of the working boys and the comparison with non-working boys are sufficient to test the idea

  9. Physical Stress May Result in Growth Suppression and Pubertal Delay in Working Boys

    Directory of Open Access Journals (Sweden)

    Mazhar Qayyum

    2011-01-01

    Full Text Available Child labor is an immense problem of Pakistan. As labor boys stay under persistent/severe physical stress, we hypothesized, that it may result in higher levels of cortisol and exhaust glycogen, fats and proteins. Depletion of fats may result in lower body weight, and insufficient leptin concentrations to excite gonadotropic releasing hormone (GnRH at the normal time of puberty in working boys. Moreover, lower testosterone levels in working boys, due to delayed puberty, may result in suppression of somatotropic axis. The Short/weak stature and failure of the onset of puberty may cause poor performance, the inferiority complex and psychological disorders. Therefore, present study is designed to find out timing of onset of the puberty in working boys. The study will include 10-18 years of working boys as a case and non-working boys of same age groups as control. Working boys will be labor boys while the control group will not be involved in physical work. A questionnaire will be used to record socioeconomic status, major diseases, nutritional status, type, and duration of work and family history of puberty, growth and obesity of subjects. Boys with familial history of pubertal delay, obesity, malnutrition, mental disorders, hematological diseases and severe/chronic diseases will be excluded. The intensity of physical working stress will be determined by a grading scale. The anthropometric data including height, weight, body mass index (BMI, bone age, tests of adiposity will be collected from subjects. The stages of pubertal onset will be determined by Tanner staging. Serum concentrations of hormones of growth, thyroid, adrenal, brain-gut and gonadal axis will be determined in nonworking and working boys. Physical and hormonal tests of the working boys and comparison with non-working boys are sufficient to test the idea.

  10. Estrus induction and fertility response in delayed pubertal Kankrej heifers treated with norgestomet ear implant

    Directory of Open Access Journals (Sweden)

    C. F. Chaudhari

    Full Text Available Aim: The study was undertaken to find out the estrus induction and fertility response in delayed pubertal Kankrej heifers treated with norgestomet ear implant. Materials and methods: Total eighteen anoestrus Kankrej heifers of delayed puberty weighed above 250 kg and attained between 30 to 36 months of age were selected and divided in to three groups of six animals each at random to conduct the experiment. Animals in group 1 were implanted Crestar ear implant for 9 days. In addition to this, group 2 received 500 IU of PMSG on the day of implant removal. In group 3, treatment protocol remained same as in group 2, but Inj. Receptal @ 2 ml was given additionally at the time of breeding. Results: All the animals exhibited estrus with average duration of 25.41+ 0.94, 21.95+ 0.20 and 22.68 + 1.46 hours between implant withdrawal and estrus induction in group 1, 2 and 3, respectively. The duration of estrus was significantly (P<0.05 longer (25.61+ 2.95 hours in group 2, followed by group 1 (18.88 + 1.45 hours and group 3 (13.48 + 1.92 hours. The pregnancy rate at induced estrus was 33.33 percent in group 2. In group 1 and group 3 none of the heifers found pregnant at induced estrus. The overall conception rate was maximum in group 2 (66.67 percent followed by group 3 (50 percent and group 1 (33.33 percent after the 3rd service. Conclusion: Although the conception rate at induced estrus was lower, norgestomet ear implant could be utilized to induced estrus in delayed pubertal cow heifers. [Vet. World 2012; 5(8.000: 453-458

  11. Pubertal Shifts in Adrenal Responsiveness to Stress and Adrenocorticotropic Hormone in Male Rats

    Science.gov (United States)

    Romeo, Russell D.; Minhas, Sumeet; Svirsky, Sarah E.; Hall, Baila S.; Savenkova, Marina; Karatsoreos, Ilia N.

    2014-01-01

    Summary Studies have indicated significant pubertal-related differences in hormonal stress reactivity. We report here that prepubertal (30d) male rats display a more protracted stress-induced corticosterone response than adults (70d), despite showing relatively similar levels of adrenocorticotropic hormone (ACTH). Additionally, we show that adrenal expression of the ACTH receptor, melanocortin 2 receptor (Mc2r), is higher in prepubertal compared to adult animals, and that expression of melanocortin receptor accessory protein (Mrap), a molecule that chaperones MC2R to the cell surface, is greater in prepubertal males following stress. Given that these data suggest a pubertal shift in adrenal sensitivity to ACTH, we directly tested this possibility by injecting prepubertal and adult males with 6.25 or 9.375 μg/kg of exogenous rat ACTH and measured their hormone levels 30 and 60 min post-injection. As these doses resulted in different circulating levels of ACTH at these two ages, we performed regression analyses to assess the relationship between circulating ACTH and corticosterone concentrations. We found no difference between the ages in the correlation between ACTH and corticosterone levels at the 30 min time point. However, 60 min following the ACTH injection, we found prepubertal rats had significantly higher corticosterone concentrations at lower levels of ACTH compared to adults. These data suggest that prolonged exposure to ACTH leads to greater corticosterone responsiveness prior to puberty, and indicate that changes in adrenal sensitivity to ACTH may, in part, contribute to the protracted hormonal stress response in prepubertal rats. PMID:24636511

  12. Tracking of anthropometric parameters and bioelectrical impedance in pubertal boys and girls.

    Science.gov (United States)

    Leppik, Aire; Jürimäe, Toivo; Jürimäe, Jaak

    2006-12-01

    The aim of this study was to investigate the anthropometric parameters and body impedance once per year during four years of the pubertal period in Estonian children. In total, 81 boys and 86 girls aged 10-11 years at the beginning of the study were investigated. Pubertal status was self-assessed by sexual maturation stages according to Tanner and physical activity index (PAI) according to Telama et al.. Body height and weight were measured and body mass index (BMI) calculated. In total, 9 skinfolds, 13 girths, 8 lengths and 8 breadths/lengths were measured according to the protocol of the International Society for the Advancement of Kinanthropometry. Somatotype components were estimated according to the method of Carter and Heath. Body impedance was measured using Multiscan 5000 (Bodystat, UK) and the impedance index (height/impedance) was calculated. The tracking of body height, weight, BMI, skinfolds, girths, lengths, breadth/lengths and body impedance was high (as a rule r> or =0.9). By increasing the time period, the correlation slightly decreased. In contrast, tracking correlations for PAI and Tanner stages were significant but quite low. Increase in mean body height was highest between 12-13 years of age (6.9 cm per year) in boys and in girls between 11-12 years of age (6.3 cm per year). In boys and girls, the peak increase in body weight was between 11 and 12 years of age, 5.7 kg and 5.2 kg, respectively. With the increasing age, body impedance decreased and impedance index increased. In conclusion, our results indicate that during puberty the detailed anthropometric parameters and body impedance tracked highly. However, the tracking of PAI and Tanner stages was significant but relatively low.

  13. Pubertal maturation and sex steroids are related to alcohol use in adolescents.

    Science.gov (United States)

    de Water, Erik; Braams, Barbara R; Crone, Eveline A; Peper, Jiska S

    2013-02-01

    Adolescents often show risk-taking behavior, including experimentation with alcohol. Previous studies have shown that advanced pubertal maturation is related to increased alcohol use in adolescents, even when controlling for age. Little is known about the underlying mechanisms of this relation between pubertal maturation and alcohol use. The goal of the present study was twofold. In Experiment 1, we investigated whether advanced pubertal maturation is associated with higher levels of alcohol use, when controlling for age. To this end, questionnaires on pubertal development and alcohol use were administered to a large sample of 797 Dutch adolescents (405 boys) aged 11-16 years. In Experiment 2, we explored whether sex steroids contribute to this relation between pubertal maturation and alcohol use by examining the association between salivary sex steroid levels and alcohol use in 168 adolescents (86 boys). It was found that, when controlling for age, advanced pubertal maturation is related to increased alcohol use in adolescent boys and girls. Controlling for age, higher testosterone and estradiol levels correlated with the onset of alcohol use in boys. In addition, higher estradiol levels were associated with a larger quantity of alcohol use in boys. Correlations between sex steroids and alcohol use were not significant in girls. These findings show that advanced pubertal maturation is related to advanced alcohol use, and that higher sex steroid levels could be one of the underlying mechanisms of this relation in boys. Sex steroids might promote alcohol use by stimulating brain regions implicated in reward processing.

  14. 7 CFR 946.62 - Effective time.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Effective time. 946.62 Section 946.62 Agriculture... Order Regulating Handling Effective Time and Termination § 946.62 Effective time. The provisions of this subpart shall become effective at such time as the Secretary may declare above his signature attached...

  15. 7 CFR 953.65 - Effective time.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Effective time. 953.65 Section 953.65 Agriculture... STATES Order Regulating Handling Effective Time and Termination § 953.65 Effective time. The provisions of this subpart shall become effective at such time as the Secretary may declare above his...

  16. 7 CFR 947.70 - Effective time.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Effective time. 947.70 Section 947.70 Agriculture... Effective Time and Termination § 947.70 Effective time. (a) The provisions of this subpart shall become effective at such time as the Secretary may declare above his signature attached to this subpart, and...

  17. Acceleration of pubertal development following pituitary radiotherapy for Cushing's disease

    Energy Technology Data Exchange (ETDEWEB)

    Nicholl, R.M.; Kirk, J.M.W.; Grossman, A.B.; Plowman, P.N.; Besser, G.M.; Savage, M.O. (Saint Bartholomew' s Hospital, London (United Kingdom))

    1993-01-01

    A 7-year-old boy with pituitary dependent Cushing's disease was treated with pituitary irradiation following unsuccessful microadenomectomy. This led to normalization of the hypercortisolaemia, but was followed by GH deficiency. Two years after radiotherapy he had the onset of pubertal development with testicular enlargement to 8 ml bilaterally. Pubertal regression was induced using the long-acting GnRH analogue goserelin. Acceleration of skeletal maturation was also arrested, resulting in improvement of final height prediction. Irradiation directly to the hypothalamo-pituitary region, as well as whole brain irradiation, may thus be associated with accelerated pubertal development. (author).

  18. Effects of leptin in female pubertal development and its interrelations with insulin, growth hormone and sex hormone%瘦素在女性青春期发育中的作用及其与胰岛素、生长激素和性激素的关系

    Institute of Scientific and Technical Information of China (English)

    孙长颢; 李颖; 王舒然; 闻颖

    2004-01-01

    BACKGROUND: Effects of leptin in pubertal development of female are controversial. The interrelations of leptin with other hormones like growth hormone, sex hormone and insulin need further exploration.OBJECTIVE: To explore the effects of leptin in female pubertal development as well as its interrelations with growth hormone, sex hormone and insulin.DESIGN: A non-randomized controlled study was conducted.SETTING and PARTICIPANTS: This study was done by Department of Nutrition and Food Hygiene, Harbin Medical University. Four hundred and fifty healthy volunteers from four schools of Dongli District attended this study.METHODS: One hundred and fifty females suffering from simple obesity aged from 7 to 17 years old, were selected. One hundred and fifty additional cases were selected respectively for normal group and malnutrition group to assay each index at 1: 1:1 with the height difference less than 2 cm and the age difference less than 3 months.MAIN OUTCOME MEASURES: Height, body mass, serum leptin, growth hormone, insulin, level of testosterone and estradiol.female gradually increased from stage B1 to B5(Tanner stage) . The leptin level of normal group(7.72 μg/L) was similar to that of malnutrition group (7.36μg/L) but was much lower than that of obesity group(12. 85 μg/L) in stage B2. However, there was significant difference among normal group, malrelation between leptin level and growth hormone(r = - 0. 10, P < 0.01) and positive correlation between leptin and insulin(r = 0. 78, P < 0. 001). There was no correlation of leptin with estradiol and testosterone.CONCLUSION: Leptin may act as a permissive factor in the onset of female pubertal development. The leptin level in stage B2 is possibly the threshold value for initiating female puberty. The rapid increase of leptin in stage B5 can inhibit the increase of growth hormone and act as the signal of puberty ending.%背景:瘦素在女性青春期发育中的作用尚有争议,且其与其他激素(生长

  19. Improving productivity through more effective time management.

    Science.gov (United States)

    Arnold, Edwin; Pulich, Marcia

    2004-01-01

    Effective time management has become increasingly important for managers as they seek to accomplish objectives in today's organizations, which have been restructured for efficiency while employing fewer people. Managers can improve their ability to manage time effectively by examining their attitudes toward time, analyzing time-wasting behaviors, and developing better time management skills. Managers can improve their performance and promotion potential with more effective time utilization. Strategies for improving time management skills are presented.

  20. A comparison of the simplified olecranon and digital methods of assessment of skeletal maturity during the pubertal growth spurt.

    Science.gov (United States)

    Canavese, F; Charles, Y P; Dimeglio, A; Schuller, S; Rousset, M; Samba, A; Pereira, B; Steib, J-P

    2014-11-01

    Assessment of skeletal age is important in children's orthopaedics. We compared two simplified methods used in the assessment of skeletal age. Both methods have been described previously with one based on the appearance of the epiphysis at the olecranon and the other on the digital epiphyses. We also investigated the influence of assessor experience on applying these two methods. Our investigation was based on the anteroposterior left hand and lateral elbow radiographs of 44 boys (mean: 14.4; 12.4 to 16.1 ) and 78 girls (mean: 13.0; 11.1 to14.9) obtained during the pubertal growth spurt. A total of nine observers examined the radiographs with the observers assigned to three groups based on their experience (experienced, intermediate and novice). These raters were required to determined skeletal ages twice at six-week intervals. The correlation between the two methods was determined per assessment and per observer groups. Interclass correlation coefficients (ICC) evaluated the reproducibility of the two methods. The overall correlation between the two methods was r = 0.83 for boys and r = 0.84 for girls. The correlation was equal between first and second assessment, and between the observer groups (r ≥ 0.82). There was an equally strong ICC for the assessment effect (ICC ≤ 0.4%) and observer effect (ICC ≤ 3%) for each method. There was no significant (p assessing skeletal maturity. The olecranon method offers detailed information during the pubertal growth spurt, while the digital method is as accurate but less detailed, making it more useful after the pubertal growth spurt once the olecranon has ossified. ©2014 The British Editorial Society of Bone & Joint Surgery.

  1. The effect of low doses of zearalenone and its metabolites on progesterone and 17β-estradiol concentrations in peripheral blood and body weights of pre-pubertal female Beagle dogs.

    Science.gov (United States)

    Gajęcka, Magdalena; Zielonka, Łukasz; Dąbrowski, Michał; Mróz, Magdalena; Gajęcki, Maciej

    2013-12-15

    The experiment involved 30 clinically healthy female Beagle dogs aged approximately 70 days with estimated initial body weight (BW) of 8 kg. The animals were randomly divided into two experimental groups (EI and EII) and a control group of 10 animals each. Group EI was intoxicated with 50 μg zearalenone/kg BW per os for 42 days, group EII received 75 μg zearalenone/kg BW per os for 42 days, and the control group was administered placebo per os for 42 days. The animals were weighed, and blood samples for analyses of the concentrations of zearalenone, its metabolites, progesterone and 17β-estradiol were collected seven times at seven-day intervals, one hour after mycotoxin administration. Biotransformation of zearalenone was observed in all groups throughout the experiment, and the highest percentage share of α-zearalenol was reported in group EII on the last five sampling dates (0.637-0.788 ng/ml, i.e. percentage share of 57.96-73.64%). The above had a significant influence on the non-physiological concentrations of progesterone and 17β-estradiol in both experimental (E) groups throughout the experiment. The lowest progesterone levels (0.131 ng/ml) were observed in group EII during the last test, and high concentrations of 17β-estradiol were found in group EII on the last two sampling dates (17.434 and 21.581 ng/ml, respectively) in comparison with control. Inhibited proliferation, manifested by a slower rate of body weight gain, was observed on the last but one day of zearalenone administration in both experimental groups. Our results indicate that NOAEL doses have stimulating/adaptive effects, whereas doses above NOAEL values suggest that even very low zearalenone doses can act as endocrine disruptors with regard to progesterone and 17β-estradiol. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Pubertal bisphenol A exposure alters murine mammary stem cell function leading to early neoplasia in regenerated glands.

    Science.gov (United States)

    Wang, Danhan; Gao, Hui; Bandyopadhyay, Abhik; Wu, Anqi; Yeh, I-Tien; Chen, Yidong; Zou, Yi; Huang, Changjiang; Walter, Christi A; Dong, Qiaoxiang; Sun, Lu-Zhe

    2014-04-01

    Perinatal exposure to bisphenol A (BPA) has been shown to cause aberrant mammary gland morphogenesis and mammary neoplastic transformation. Yet, the underlying mechanism is poorly understood. We tested the hypothesis that mammary glands exposed to BPA during a susceptible window may lead to its susceptibility to tumorigenesis through a stem cell-mediated mechanism. We exposed 21-day-old Balb/c mice to BPA by gavage (25 μg/kg/d) during puberty for 3 weeks, and a subset of animals were further challenged with one oral dose (30 mg/kg) of 7,12-dimethylbenz(a)anthracene (DMBA) at 2 months of age. Primary mammary cells were isolated at 6 weeks, and 2 and 4 months of age for murine mammary stem cell (MaSC) quantification and function analysis. Pubertal exposure to the low-dose BPA increased lateral branches and hyperplasia in adult mammary glands and caused an acute increase of MaSC in 6-week-old glands and a delayed increase of luminal progenitors in 4-month-old adult gland. Most importantly, pubertal BPA exposure altered the function of MaSC from different age groups, causing early neoplastic lesions in their regenerated glands similar to those induced by DMBA exposure, which indicates that MaSCs are susceptible to BPA-induced transformation. Deep sequencing analysis on MaSC-enriched mammospheres identified a set of aberrantly expressed genes associated with early neoplastic lesions in patients with human breast cancer. Thus, our study for the first time shows that pubertal BPA exposure altered MaSC gene expression and function such that they induced early neoplastic transformation.

  3. Does soaking temperature during controlled slow freezing of pre-pubertal mouse testes influence course of in vitro spermatogenesis?

    Science.gov (United States)

    Arkoun, Brahim; Dumont, Ludovic; Milazzo, Jean-Pierre; Rondanino, Christine; Bironneau, Amandine; Wils, Julien; Rives, Nathalie

    2016-06-01

    The banking of testicular tissue before highly gonadotoxic treatment is a prerequisite for the preservation of fertility in pre-pubertal boys not yet producing sperm. The aim of the current study is to evaluate the impact of a soaking temperature performed at -7 °C, -8 °C or -9 °C on the ability of frozen-thawed mouse spermatogonial stem cells (SSCs) to generate haploid germ cells after in vitro maturation. Testes of 6.5-day-old post-partum CD-1 mice were cryopreserved by using a controlled slow freezing protocol with soaking at -7 °C, -8 °C or -9 °C. Frozen-thawed pre-pubertal testicular tissues were cultured in vitro on agarose gel for 30 days. Histological evaluations were performed and flagellated late spermatids were counted after mechanical dissection of the cultured tissues. The differentiation of frozen SSCs into elongated spermatids was more efficient after treatment at -9 °C than at -7 °C and -8 °C. After dissection, flagellated late spermatids were observed by using Shorr staining. The number of flagellated late spermatids was significantly decreased after slow freezing when compared with a fresh tissue control. Therefore, the soaking temperature during slow freezing of pre-pubertal mouse testicular tissue might positively influence the course of in vitro spermatogenesis. Our slow freezing protocol with a soaking temperature at -9 °C was the optimal condition in terms of the achievement of in vitro spermatogenesis with a higher production of elongated spermatids, although the effectiveness of the maturation process was reduced compared with the fresh tissue control.

  4. Association between self-concept and body weight, gender, and pubertal development among male and female adolescents.

    Science.gov (United States)

    O'Dea, J A; Abraham, S

    1999-01-01

    This study examined the effects and interactions of gender, pubertal status, and body weight on the self-concept of 462 young adolescent Australian students from two different schools. All students enrolled in Years 7 and 8 completed the Self-Perception Profile for Adolescents, which includes several self-concept subscales and ratings of the importance of each subscale. The self-concept subscales ranked as most important by male and female students were Close Friendship, Scholastic Competence, and Job Competence. Females rated their ability to form close friendships significantly higher and of greater importance than did males. Standard body weight was related to students' Physical Appearance subscale scores, with higher weight students having lower self-concept, and postmenarcheal females having the poorest opinion of their physical appearance. Higher body weight males had lower scores on Athletic Competence, Job Competence, and Behavioral Conduct than did other males. Overweight females and normal weight males considered athletic competence to be more important than did other students. Pubertal status was related to students' scores on Athletic Competence, with postpubertal males who were not overweight scoring highest, and on Physical Appearance, with postmenarcheal females having the lowest opinion of their appearance. The mean self-concept score was significantly related to students' standard body weight, and there was an interaction between gender and puberty, with postpubertal males having the highest and postmenarcheal females the lowest self-concept score. The discrepancy score suggested that females felt they had failed to meet their ideal self-concept significantly more than did males. The results suggest that school programs should be implemented to provide exercise and job skill training suitable for all students, especially those who are overweight. These programs, while taking into account students' pubertal status, should aim to improve self

  5. A pre-pubertal girl with giant juvenile fibroadenoma: A rare case report

    Directory of Open Access Journals (Sweden)

    Kumar Gaurav

    2015-01-01

    Conclusion: Through this case we want to emphasize that these giant benign neoplasms should be suspected in any pre-pubertal girl with breast lump and should always be treated with breast conserving surgery.

  6. Insulin resistance in obese pre-pubertal children: Relation to body ...

    African Journals Online (AJOL)

    Heba Elsedfy

    2014-04-16

    Apr 16, 2014 ... sensitivity indices and investigate its relationship with abdominal fat distribution by Dual energy ... associated with negative metabolic predictors in pubertal ..... metabolic determinants of nonalcoholic fatty liver disease in.

  7. Maternal pre-pregnancy body mass index and pubertal development among sons

    DEFF Research Database (Denmark)

    Hounsgaard, M L; Håkonsen, L B; Vested, A

    2013-01-01

    Maternal overweight and obesity in pregnancy has been associated with earlier age of menarche in daughters as well as reduced semen quality in sons. We aimed at investigating pubertal development in sons born by mothers with a high body mass index (BMI). The study included 2522 sons of mothers...... that during pregnancy in 1984-1987 were enrolled in a mother-child cohort and gave information on their pre-pregnancy height and weight from which we calculated their BMI. Information on sons' pubertal development, assessed by age when starting regular shaving, voice break, acne and first nocturnal emission...... indicators of pubertal development, results also indicated earlier pubertal development among sons of obese mothers. After excluding sons of underweight mothers in a subanalysis, we observed an inverse trend between maternal pre-pregnancy BMI and age at regular shaving, acne and first nocturnal emission...

  8. [Consumptions of Meat and Dairy Products, Zinc Intake and Pubertal Development in Adolescents in Chengdu].

    Science.gov (United States)

    Luo, Jiao; Yang, Ming-zhe; Duan, Ruo-nan; Tian, Guo; Bao, Yu-xin; Chen, Yan-rong; Xue, Hong-mei; Liu, Yan; Cheng, Guo

    2015-09-01

    To determine the associations between meat, dairy and zinc intake and pubertal development in adolescents in Chengdu. A total of 1320 children and adolescents aged 9-15 years in Chengdu were recruited using a stratified cluster sampling strategy. Dietary intake was assessed by the food frequency questionnaire (FFQ) and 3-day 24-hour dietary recall. Pubertal development was evaluated through physical examinations. Consumptions of meat and dairy, and zinc intake were compared between groups with different levels of pubertal development according to the Tanner criteria. The median age of spermarche was 13. 00 years. The boys who had had spermarche consumed more meat (including red meat) and dairy products than those who had not yet (Pmeat was positively correlated with the level of pubertal development (Pmeat and less diiry products than those who had not yet (Pproducts was negatively associated with breast development and the level of pubertal development (P meat, red meat and dairy products are associated with pubertal development in adolescents in Chengdu. However, the differences between boys and girls warrant further studies.

  9. PRE-PUBERTAL CHILDREN AND EXERCISE IN HOT AND HUMID ENVIRONMENTS: A BRIEF REVIEW

    Directory of Open Access Journals (Sweden)

    Wade H. Sinclair

    2007-12-01

    Full Text Available The ability of pre-pubertal children to regulate their body temperature under thermoneutral environments is similar to that of an adult albeit via differing routes. However, this ability is challenged when exposed to extreme environments. Thermoregulatory responses of pre-pubertal children differ from adults via adaptations that occur during growth and maturation and disadvantage children when exercising in hot and humid environments. When ambient temperatures exceed that of the skin, an influx of thermal energy from the environment increases thermal stress. When coupled with exercise, the increased thermal stress results in reduced physical performance and an increased risk of developing heat-related illness. Evidence suggesting the severity of heat-related illness is greater in pre-pubertal children than adults is inconclusive because age-related differences in thermoregulatory responses are attributed to either morphologic or functional changes. Additionally, the majority of research on pre-pubertal children exercising in the heat has been maturational or comparative studies with adults conducted in the near absence of convective cooling, complicating extrapolation to field-based environments. However, current consensus is that pre-pubertal children are disadvantaged when exercising in extreme temperatures and that care should be taken in preparing for and conducting sporting activities in hot and humid environments for pre-pubertal children

  10. The roles of puberty and age in explaining the diminished effectiveness of parental buffering of HPA reactivity and recovery in adolescence.

    Science.gov (United States)

    Doom, Jenalee R; Hostinar, Camelia E; VanZomeren-Dohm, Adrienne A; Gunnar, Megan R

    2015-09-01

    Parental support is a powerful regulator of stress and fear responses for infants and children, but recent evidence suggests it may be an ineffective stress buffer for adolescents. The mechanisms underlying this developmental shift are not well-understood. The goal of the present study was to examine the independent and joint contributions of pubertal status and chronological age in explaining this shift. A sample of 75 typically developing youth (M age=12.95 years, SD=0.70, range=11.7-14.6 years; 37 females) was recruited to complete a modified Trier Social Stress Test (TSST-M) in the laboratory. Participants were recruited in such a way as to disentangle pubertal stage and chronological age by phone screening for markers of pubertal stage and then recruiting roughly equal numbers of younger and older, pre/early and mid/late pubertal youth who were then randomly assigned within groups to condition. The TSST-M was used as the stressor and youth prepared either with their parent or stranger (parent condition: N=39). Pubertal stage was confirmed by the Petersen Pubertal Development Scale at the time of testing and treated, along with chronological age, as a continuous variable in the analyses. The results revealed an interaction of pubertal stage and support condition for cortisol reactivity to the TSST-M such that preparing for the speech with the parent became a less potent buffer of the HPA axis as pubertal stage increased. Age did not interact with condition in predicting cortisol reactivity. In contrast, the parent's presence during speech preparation decreased in its effectiveness to hasten recovery of the HPA axis as children got older, but pubertal stage was not predictive of recovery rate. These patterns were specific to cortisol and were not observed with salivary alpha-amylase levels or subjective stress ratings for the task. These analyses suggest that the switch away from using parents as social buffers may be the result of neurobiological mechanisms

  11. Gender differences in sagittal standing alignment before pubertal peak growth: the importance of subclassification and implications for spinopelvic loading.

    Science.gov (United States)

    Dolphens, Mieke; Cagnie, Barbara; Vleeming, Andry; Vanderstraeten, Guy; Danneels, Lieven

    2013-12-01

    The aim of this study was to analyze gender differences in sagittal standing alignment at pre-peak height velocity age thereby applying a scientifically sound and practically oriented classification scheme for overall standing balance. The study population consisted of healthy boys (n = 639) and girls (n = 557) before pubertal peak growth. During subjects' habitual standing, sagittal plane measures of the spine, pelvis and lower limbs were collected using a clinical screening protocol. With each subject classified as one of three postural types (neutral, sway-back, or leaning-forward), differences in sagittal plane alignment were analyzed between sexes. The results revealed clear differences between genders in each of the postural types. Within the neutral and sway-back postural subgroups, boys presented more forward inclination of the trunk, more thoracic kyphosis and more pelvis backtilt compared with girls. Within the leaning-forward category, girls displayed more forward trunk lean, less thoracic kyphosis and more pelvic anteversion. A state of lumbar segmental hyperextension appeared to exist in female leaning-forward subjects. Our results reveal for the first time that sagittal standing alignment is different between prepubescent boys and girls when subjects are appropriately subclassified, and conversely represent a 'wash-out effect' when pooled. When the classification system is applied, gender-specificity in gravity line position is suggested, implying gender-related differences in lever arms and thus load. Present findings may add to our understanding of gender-specific biomechanical challenges posed by habitual posture, and may shed new light on sagittal standing alignment as a possible contributory factor in developmental spinal-pelvic disorders.

  12. Timing effects in health valuations.

    Science.gov (United States)

    Leiter, Andrea M; Pruckner, Gerald J

    2014-06-01

    This paper analyzes the impact of external sources of information, conveyed by the frequency of risky events that vary across time, on the individual willingness to pay (WTP) for a reduction of mortality risk. We collected data from a contingent valuation (CV) exercise conducted in two waves (fall and winter) to examine whether individual WTP varied across periods that differed in the predominance of fatal accidents. Risk valuations were based on fatal snow avalanche accidents, that is, a type of risk with seasonal differences in occurrence. We found slightly lower but statistically significant mean WTP figures in the winter than in the fall sample because of time-varying individual risk attitudes and, therefore, recommend controlling for these factors in risk assessment CV surveys.

  13. 7 CFR 917.60 - Effective time.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Effective time. 917.60 Section 917.60 Agriculture... CALIFORNIA Order Regulating Handling Miscellaneous Provisions § 917.60 Effective time. The provisions of this part and of any amendment thereto, shall become effective at such time as the Secretary may...

  14. 7 CFR 929.68 - Effective time.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Effective time. 929.68 Section 929.68 Agriculture... Effective time. The provisions of this part, and of any amendment thereto, shall become effective at such time as the Secretary may declare above his signature and shall continue in force until terminated...

  15. 7 CFR 923.63 - Effective time.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Effective time. 923.63 Section 923.63 Agriculture... COUNTIES IN WASHINGTON Order Regulating Handling Miscellaneous Provisions § 923.63 Effective time. The provisions of this part, and of any amendment thereto, shall become effective at such time as the...

  16. 7 CFR 959.83 - Effective time.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Effective time. 959.83 Section 959.83 Agriculture... Regulating Handling Miscellaneous Provisions § 959.83 Effective time. The provisions of this subpart, or any amendment thereto, shall become effective at such time as the Secretary may declare and shall continue...

  17. 7 CFR 989.90 - Effective time.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Effective time. 989.90 Section 989.90 Agriculture... CALIFORNIA Order Regulating Handling Miscellaneous Provisions § 989.90 Effective time. The provisions of this amended subpart, as well as any amendments to this amended subpart shall become effective at such time...

  18. 7 CFR 924.63 - Effective time.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Effective time. 924.63 Section 924.63 Agriculture... § 924.63 Effective time. The provisions of this part and any amendments thereto shall become effective at such time as the Secretary may declare above his signature, and shall continue in force...

  19. 7 CFR 915.63 - Effective time.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Effective time. 915.63 Section 915.63 Agriculture... Regulating Handling Miscellaneous Provisions § 915.63 Effective time. The provisions of this part shall become effective at such time as the Secretary may declare above his signature to this part, and...

  20. 7 CFR 930.82 - Effective time.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Effective time. 930.82 Section 930.82 Agriculture... Miscellaneous Provisions § 930.82 Effective time. The provisions of this part, and of any amendment thereto, shall become effective at such time as the Secretary may declare, and shall continue in force...

  1. 7 CFR 945.82 - Effective time.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Effective time. 945.82 Section 945.82 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... § 945.82 Effective time. The provisions of this subpart shall become effective at such time as...

  2. 7 CFR 958.70 - Effective time.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Effective time. 958.70 Section 958.70 Agriculture... COUNTIES IN IDAHO, AND MALHEUR COUNTY, OREGON Order Regulating Handling Effective Time and Termination § 958.70 Effective time. The provisions of this subpart, or any amendment thereto, shall...

  3. 7 CFR 927.77 - Effective time.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Effective time. 927.77 Section 927.77 Agriculture... Order Regulating Handling Miscellaneous Provisions § 927.77 Effective time. The provisions of this subpart and of any amendment thereto shall become effective at such time as the Secretary may declare,...

  4. 7 CFR 985.71 - Effective time.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Effective time. 985.71 Section 985.71 Agriculture....71 Effective time. The provisions of this subpart, and of any amendment thereto, shall become effective at such time as the Secretary may declare and shall continue in force until terminated...

  5. 7 CFR 983.87 - Effective time.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Effective time. 983.87 Section 983.87 Agriculture..., ARIZONA, AND NEW MEXICO Miscellaneous Provisions § 983.87 Effective time. The provisions of this part, as well as any amendments, shall become effective at such time as the Secretary may declare, and...

  6. 7 CFR 993.89 - Effective time.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Effective time. 993.89 Section 993.89 Agriculture... Order Regulating Handling Miscellaneous Provisions § 993.89 Effective time. The provisions of this subpart, as well as any amendments to this subpart, shall become effective at such time as the...

  7. 7 CFR 916.63 - Effective time.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Effective time. 916.63 Section 916.63 Agriculture... Regulating Handling Miscellaneous Provisions § 916.63 Effective time. The provisions of this part, and of any amendment thereto, shall become effective at such time as the Secretary may declare above his signature...

  8. 7 CFR 932.67 - Effective time.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Effective time. 932.67 Section 932.67 Agriculture... Regulating Handling Miscellaneous Provisions § 932.67 Effective time. The provisions of this subpart, as well as any amendments to this subpart, shall become effective at such time as the Secretary may...

  9. 7 CFR 906.54 - Effective time.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Effective time. 906.54 Section 906.54 Agriculture... RIO GRANDE VALLEY IN TEXAS Order Regulating Handling Miscellaneous Provisions § 906.54 Effective time. The provisions of this subpart, or any amendment thereto, shall become effective at such time as...

  10. 7 CFR 966.83 - Effective time.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Effective time. 966.83 Section 966.83 Agriculture... Regulating Handling Miscellaneous Provisions § 966.83 Effective time. The provisions of this subpart, or any amendment thereto, shall become effective at such time as the Secretary may declare and shall continue...

  11. 7 CFR 922.63 - Effective time.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Effective time. 922.63 Section 922.63 Agriculture... IN WASHINGTON Order Regulating Handling Miscellaneous Provisions § 922.63 Effective time. The provisions of this part, and of any amendment thereto, shall become effective at such time as the...

  12. 7 CFR 948.83 - Effective time.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Effective time. 948.83 Section 948.83 Agriculture... Order Regulating Handling Miscellaneous Provisions § 948.83 Effective time. The provisions of this subpart or any amendments thereto shall become effective at such time as the Secretary may declare...

  13. Relationships between urinary biomarkers of phytoestrogens, phthalates, phenols, and pubertal stages in girls

    Directory of Open Access Journals (Sweden)

    Chakraborty TR

    2012-01-01

    Full Text Available Tandra R Chakraborty1, Eilliut Alicea1, Sanjoy Chakraborty21Department of Biology, Adelphi University, One South Avenue, Garden City; 2Department of Biological Sciences, New York City College of Technology, New York, NY, USAAbstract: Phytoestrogens, phthalates, and phenols are estrogen-disrupting chemicals that have a pronounced effect at puberty. They are exogenous chemicals that are either plant-derived or man-made, and can alter the functions of the endocrine system and cause various health defects by interfering with the synthesis, metabolism, binding, or cellular responses of natural estrogens. Phytoestrogens, phthalates, and phenols are some of the potent estrogens detectable in urine. Phytoestrogens are plant-derived xenestrogens found in a wide variety of food products, like soy-based food, beverages, several fruits, and vegetables. Exposure to phytoestrogens can delay breast development and further lead to precocious puberty. The effect of phytoestrogens is mediated through estrogen receptors α and β or by binding with early immediate genes, such as jun and fos. Phthalates are multifunctional synthetic chemicals used in plastics, polyvinyl chloride products, cosmetics, hair spray, and children's toys. Phthalates have been shown to cause defeminization, thelarche, precocious puberty, and an increase in breast and pubic hair in pubertal girls. However, reports are also available that show no association of phthalates with precocious puberty in girls. Phthalates can act through a receptor-mediated signaling pathway or affect the production of luteinizing hormone and follicle-stimulating hormone that has a direct effect on estrogen formation. Phenols like bisphenol A are industrial chemicals used mainly in the manufacture of polycarbonates and plastic materials. Bisphenol A has been shown to cause precocious puberty and earlier menarche in pubertal girls. Reports suggest that the neurotoxic effect of bisphenol A can be mediated either by

  14. Maternal swimming exercise during pregnancy attenuates anxiety/depressive-like behaviors and voluntary morphine consumption in the pubertal male and female rat offspring born from morphine dependent mothers.

    Science.gov (United States)

    Torabi, Masoumeh; Pooriamehr, Alireza; Bigdeli, Imanollah; Miladi-Gorji, Hossein

    2017-09-01

    This study was designed to examine whether maternal swimming exercise during pregnancy would attenuate prenatally morphine-induced anxiety, depression and voluntary consumption of morphine in the pubertal male and female rat offspring. Pregnant rats during the development of morphine dependence were allowed to swim (30-45min/d, 3days per a week) on gestational days 11-18. Then, the pubertal male and female rat offspring were tested for the elevated plus-maze (EPM), sucrose preference test (SPT) and voluntary morphine consumption using a two-bottle choice (TBC) paradigm. The results showed that male and female rat offspring born of the swimmer morphine-dependent mothers exhibited an increase in EPM open arm time and entries, higher levels of sucrose preference than their sedentary control mothers. Voluntary consumption of morphine was less in the male and female rat offspring born of the swimmer morphine-dependent mothers as compared with their sedentary control mothers during three periods of the intake of drug. Thus, swimming exercise in pregnant morphine dependent mothers decreased anxiety, depressive-like behavior and also the voluntary morphine consumption in the pubertal male and female offspring, which may prevent prenatally morphine-induced behavioral sensitization in offspring. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Attachment, parenting styles and bullying during pubertal years.

    Science.gov (United States)

    van der Watt, Ronél

    2014-01-01

    Research that focuses on combining attachment, parenting styles, bullying and the reciprocal nature thereof in the parent-adolescent and peer relationships is limited. The bio-psychosocial changes that adolescents experience open up broader social realities and are perceived differently by parents and adolescents. Attachment processes and parenting styles may elicit dissimilar perceptions. These processes are also associated with the multifaceted dynamics of bullying. The aim of the article is to advocate for research on the possible link between the implications of attachment, parenting styles and bullying. Exploring the association between attachment, parenting styles and bullying can deepen the understanding of the developmental challenges within the parent-adolescent relationship, add insight to the different perceptions of adolescents and parents, and complement intervention programmes accordingly. Firstly, this article outlines bio-psychosocial changes in the pubertal years as related to the social realities of the adolescent. Secondly, a discussion on the concepts 'attachment', 'parenting styles', 'bullying', and the potential link between these concepts will follow. Thirdly, an outline of the clinical implications of the apparent association between these concepts is given. The article concludes with recommendations that researchers can consider while exploring the relationship between attachment, parenting styles, and bullying and the delineation thereof in the parent-adolescent relationship.

  16. EFFECTIVE SAVINGS IN PRODUCTION TIMES AND COST

    African Journals Online (AJOL)

    ES OBE

    THROUGH MONITORING OF THE EFFECT OF ADDITIVES AND ... planning, using the in-depth knowledge of gel times, can there be a saving in production times and prevention of material ..... production lines staff handlay-up laminators and ...

  17. Effective Feature Preprocessing for Time Series Forecasting

    DEFF Research Database (Denmark)

    Zhao, Junhua; Dong, Zhaoyang; Xu, Zhao

    2006-01-01

    Time series forecasting is an important area in data mining research. Feature preprocessing techniques have significant influence on forecasting accuracy, therefore are essential in a forecasting model. Although several feature preprocessing techniques have been applied in time series forecasting...... performance in time series forecasting. It is demonstrated in our experiment that, effective feature preprocessing can significantly enhance forecasting accuracy. This research can be a useful guidance for researchers on effectively selecting feature preprocessing techniques and integrating them with time...... series forecasting models....

  18. Time varying effects in survival analysis

    DEFF Research Database (Denmark)

    Scheike, Thomas H.

    2002-01-01

    additive risk model; counting process; proportional hazards model; semi-parametric models; survival data; time-varying effects; nonparametric testing......additive risk model; counting process; proportional hazards model; semi-parametric models; survival data; time-varying effects; nonparametric testing...

  19. 7 CFR 905.82 - Effective time.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Effective time. 905.82 Section 905.82 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... TANGELOS GROWN IN FLORIDA Order Regulating Handling Miscellaneous Provisions § 905.82 Effective time....

  20. 7 CFR 996.75 - Effective time.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Effective time. 996.75 Section 996.75 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Effective time. The provisions of this part, as well as any amendments, shall apply to 2003-04...

  1. Impact of Pubertal Development and Physical Activity on Heart Rate Variability in Overweight and Obese Children in Taiwan

    Science.gov (United States)

    Chen, Su-Ru; Chiu, Hung-Wen; Lee, Yann-Jinn; Sheen, Tzong-Chi; Jeng, Chii

    2012-01-01

    Child obesity is frequently associated with dysfunction of autonomic nervous system. Children in pubertal development were suggested to be vulnerable to autonomic nervous system problems such as decrease of heart rate variability from dysregulation of metabolic control. This study explored the influence of pubertal development on autonomic nervous…

  2. Impact of Pubertal Development and Physical Activity on Heart Rate Variability in Overweight and Obese Children in Taiwan

    Science.gov (United States)

    Chen, Su-Ru; Chiu, Hung-Wen; Lee, Yann-Jinn; Sheen, Tzong-Chi; Jeng, Chii

    2012-01-01

    Child obesity is frequently associated with dysfunction of autonomic nervous system. Children in pubertal development were suggested to be vulnerable to autonomic nervous system problems such as decrease of heart rate variability from dysregulation of metabolic control. This study explored the influence of pubertal development on autonomic nervous…

  3. Endothelial function in pre-pubertal children at risk of developing cardiomyopathy: a new frontier

    Directory of Open Access Journals (Sweden)

    Aline Cristina Tavares

    2012-01-01

    Full Text Available Although it is known that obesity, diabetes, and Kawasaki's disease play important roles in systemic inflammation and in the development of both endothelial dysfunction and cardiomyopathy, there is a lack of data regarding the endothelial function of pre-pubertal children suffering from cardiomyopathy. In this study, we performed a systematic review of the literature on pre-pubertal children at risk of developing cardiomyopathy to assess the endothelial function of pre-pubertal children at risk of developing cardiomyopathy. We searched the published literature indexed in PubMed, Bireme and SciELO using the keywords 'endothelial', 'children', 'pediatric' and 'infant' and then compiled a systematic review. The end points were age, the pubertal stage, sex differences, the method used for the endothelial evaluation and the endothelial values themselves. No studies on children with cardiomyopathy were found. Only 11 papers were selected for our complete analysis, where these included reports on the flow-mediated percentage dilatation, the values of which were 9.80±1.80, 5.90±1.29, 4.50±0.70, and 7.10±1.27 for healthy, obese, diabetic and pre-pubertal children with Kawasaki's disease, respectively. There was no significant difference in the dilatation, independent of the endothelium, either among the groups or between the genders for both of the measurements in children; similar results have been found in adolescents and adults. The endothelial function in cardiomyopathic children remains unclear because of the lack of data; nevertheless, the known dysfunctions in children with obesity, type 1 diabetes and Kawasaki's disease may influence the severity of the cardiovascular symptoms, the prognosis, and the mortality rate. The results of this study encourage future research into the consequences of endothelial dysfunction in pre-pubertal children.

  4. [Dietary Fiber and Pubertal Development among Children and Adolescents--a Cross-sectional Study in Chengdu, Sichuan].

    Science.gov (United States)

    Tian, Guo; Liu, Yan; Xue, Hong-mei; Luo, Jiao; Chen, Yan-rong; Bao, Yu-xin; Duan, Ruo-nan; Yang, Ming-zhe; Cheng, Guo

    2016-03-01

    To determine the association between intake of dietary fiber and pubertal development among children and adolescents in Chengdu. A cross-sectional survey was undertaken in 1 340 children and adolescents aged 9-15 years. Data about dietary intake were collected through 24-h dietary self-recall. Pubertal development was measured by trained investigators using Tanner criteria. Consumptions of total fiber and fiber from different sources were compared among the participants with different stages of pubertal development. Data from 1 328 children and adolescents were analyzed. Boys (n = 667) at a later stage of pubertal development consumed less total fiber and fruit fiber than those at an earlier stage (P fiber than those at an earlier stage (P Dietary fiber intake, especially fruit fiber, is lower in children and adolescents with early commencement of puberty development. Further studies are needed to establish the relationship between dietary fiber and pubertal development.

  5. Serum levels of INSL3, AMH, Inhibin B and Testosterone during pubertal transition in healthy boys

    DEFF Research Database (Denmark)

    Lindhardt Johansen, Marie; Anand-Ivell, Ravinder; Mouritsen, Annette;

    2014-01-01

    to luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone, inhibin B, and anti-Müllerian hormone (AMH) during puberty in healthy boys.MethodsTen boys were included from the longitudinal part of the COPENHAGEN Puberty Study. Pubertal evaluation, including testicular volume, was performed......IntroductionInsulin-like factor 3 (INSL3) is a promising marker of Leydig cell function with potentially high clinical relevance. Limited data of INSL3 levels in relation to other reproductive hormones in healthy pubertal boys exist.AimTo evaluate longitudinal serum changes in INSL3 compared...

  6. Pubertal development and fertility in survivors of childhood acute myeloid leukemia treated with chemotherapy only

    DEFF Research Database (Denmark)

    Molgaard-Hansen, Lene; Skou, Anne-Sofie; Juul, Anders

    2013-01-01

    More than 60% of children with acute myeloid leukemia (AML) become long-term survivors. Most are cured using chemotherapy without hematopoietic stem cell transplantation (HSCT). We report on pubertal development and compare self-reported parenthood among AML survivors and their siblings.......More than 60% of children with acute myeloid leukemia (AML) become long-term survivors. Most are cured using chemotherapy without hematopoietic stem cell transplantation (HSCT). We report on pubertal development and compare self-reported parenthood among AML survivors and their siblings....

  7. Mutation analysis of cathepsin C gene in a Chinese patient with pre-pubertal periodontitis

    Institute of Scientific and Technical Information of China (English)

    YANG Yuan; BAI Xiao-wen; SONG Shu-juan; GE Li-hong; CAO Cai-fang

    2005-01-01

    @@ Pre-pubertal periodontitis (PPP) is a rare and rapidly progressive form of early onset periodontitis resulting in premature tooth loss of primary and permanent dentitions. Mutations in cathepsin C (CTSC) gene have been found in patients with pre-pubertal periodontitis and Papillon-Lefevre syndrome which also characterized with severe periodontitis and palmoplantar hyperkera-tosis.1-3 To date, more than 40 mutations of CTSC gene have been identified in ethnically diverse people worldwide.4 However, there is no such genetic analysis in China. In the present study, we report the mutation analysis of a Chinese patient with PPP.

  8. Treatment timing of MARA and fixed appliance therapy of Class II malocclusion.

    Science.gov (United States)

    Ghislanzoni, Luis Tomas Huanca; Baccetti, Tiziano; Toll, Douglas; Defraia, Efisio; McNamara, James A; Franchi, Lorenzo

    2013-06-01

    The objective of this study is to evaluate the effect of timing on Mandibular Anterior Repositioning Appliance (MARA) and fixed appliance treatment of Class II malocclusion in a prospective clinical trial. The treated sample consisted of 51 consecutively treated patients at prepubertal (n = 21), pubertal (n = 15), and postpubertal (n = 15) stages of development. Control groups for the three treated groups were generated from growth data of untreated Class II subjects. Lateral cephalograms were digitized and superimposed via cephalometric software at T1 (pre-treatment) and T2 (after comprehensive treatment). The T1-T2 changes in the treated groups were compared to those in their corresponding control groups with Mann-Whitney tests with Bonferroni correction. Mandibular elongation was greater at the pubertal stage (Co-Gn +2.6 mm, with respect to controls). Headgear effect on the maxilla was greater in the pre-peak sample (Co-A -1.9 mm, with respect to controls). Dentoalveolar compensations (proclination of lower incisors, extrusion and mesialization of lower molars, and reduction in the overbite) were significant in the pre-peak and post-peak groups. Optimal timing for Class II treatment with MARA appliance is at the pubertal growth spurt, with enhanced mandibular skeletal changes and minimal dentoalveolar compensations.

  9. Effects of maxillary protraction in pre-pubertal patients with unilateral cleft lip and palate%前方牵引治疗单侧完全性唇腭裂患者术后前牙反(牙合)畸形的研究

    Institute of Scientific and Technical Information of China (English)

    贾海潮; 李巍然; 林久祥

    2009-01-01

    目的 探讨前方牵引治疗单侧完全性唇腭裂(UCLP)患者术后前牙反(牙合)畸形的效果.方法 进行前瞻性临床研究设计,UCLP术后骨性前牙反骀患者治疗组18例,年龄9.63±1.24岁,观察对照组14例,平均8.71±1.92岁,均处于生长发育高峰前期.使用前方牵引进行治疗,治疗或观察前后拍摄头颅侧位片并测量,进行成组设计和配对设计t检验.结果 UCLP治疗组前方牵引后,上颌骨前移;下颌后移合并后下旋转;上下颌间关系和面型改善明显,上颌与下颌改变的比值为1:1.7.对照组上下颌不调、前牙反覆盖、凹面型加重.结论 UCLP术后轻中度骨性前牙反(牙合)畸形,前方牵引能够促进上颌骨向前,改善上下颌骨关系和软组织面型,应该早期矫形治疗.%Objective To investigate the effects of maxillary protraction on anterior crossbite in repaired pre-pubertal patients with complete unilateral cleft lip and palate(UCLP).Methods Prospective controlled clinical trial was carried out.Eighteen UCLP patients with anterior crossbite,aged 9.63±1.24 years,were the experimental subjects.Fourteen UCLP patients with similar malocclusion,aged 8.71±1.92 years,were selected as controls.All patients were before puberty according to the evaluation of the hand wrist radiograms.A Hyrax appliance and reverse headgear were applied.Lateral cephalometric radiographs were taken before and after the treatment.Computerized cephalometric analysis was carried out.Results After treatment in experimental group.the maxilla moved forward more significantly.The mandible rotated downward and backward.The intermaxillary relationship and soft tissue profile improved significantly.The rate of maxillary and mandibular Contribution was 1:1.7. ConelusionsMaxillary protraction could improve the imermaxillary relationship and soft tissue profile in UCLP patients with mild or moderate skeletal deformity before puberty.

  10. Emotion and Implicit Timing: The Arousal Effect

    Science.gov (United States)

    Droit-Volet, Sylvie; Berthon, Mickaël

    2017-01-01

    This study tested the effects of emotion on implicit time judgment. The participants did not receive any overt temporal instructions. They were simply trained to respond as quickly as possible after a response signal, which was separated from a warning signal by a reference temporal interval. In the testing phase, the inter-signal interval was shorter, equal or longer than the reference interval and was filled by emotional pictures (EP) of different arousal levels: high, moderate, and low. The results showed a U-shaped curve of reaction time plotted against the interval duration, indicating an implicit processing of time. However, this RT-curve was shifted toward the left, with a significantly lower peak time for the high-arousal than for the low-arousal EP. This emotional time distortion in an implicit timing task suggests an automatic effect of emotion on the internal clock rate. PMID:28261125

  11. Longitudinal changes in adolescent risk-taking: a comprehensive study of neural responses to rewards, pubertal development, and risk-taking behavior.

    Science.gov (United States)

    Braams, Barbara R; van Duijvenvoorde, Anna C K; Peper, Jiska S; Crone, Eveline A

    2015-05-01

    Prior studies have highlighted adolescence as a period of increased risk-taking, which is postulated to result from an overactive reward system in the brain. Longitudinal studies are pivotal for testing these brain-behavior relations because individual slopes are more sensitive for detecting change. The aim of the current study was twofold: (1) to test patterns of age-related change (i.e., linear, quadratic, and cubic) in activity in the nucleus accumbens, a key reward region in the brain, in relation to change in puberty (self-report and testosterone levels), laboratory risk-taking and self-reported risk-taking tendency; and (2) to test whether individual differences in pubertal development and risk-taking behavior were contributors to longitudinal change in nucleus accumbens activity. We included 299 human participants at the first time point and 254 participants at the second time point, ranging between ages 8-27 years, time points were separated by a 2 year interval. Neural responses to rewards, pubertal development (self-report and testosterone levels), laboratory risk-taking (balloon analog risk task; BART), and self-reported risk-taking tendency (Behavior Inhibition System/Behavior Activation System questionnaire) were collected at both time points. The longitudinal analyses confirmed the quadratic age pattern for nucleus accumbens activity to rewards (peaking in adolescence), and the same quadratic pattern was found for laboratory risk-taking (BART). Nucleus accumbens activity change was further related to change in testosterone and self-reported reward-sensitivity (BAS Drive). Thus, this longitudinal analysis provides new insight in risk-taking and reward sensitivity in adolescence: (1) confirming an adolescent peak in nucleus accumbens activity, and (2) underlining a critical role for pubertal hormones and individual differences in risk-taking tendency.

  12. State of the art of time effectiveness

    NARCIS (Netherlands)

    Scheerens, J.; Scheerens, J.

    2014-01-01

    In this chapter comprehensive reviews and earlier meta-analyses are summarized to arrive at an impression of the effectiveness of the various ways in which educational time can be intensified, enhanced, and expanded. The chapter has three main sections, one on “within school time,” one on homework,

  13. Regulation of gonadal sex ratios and pubertal development by the thyroid endocrine system in zebrafish (Danio rerio)

    Science.gov (United States)

    Sharma, Prakash; Patino, Reynaldo

    2013-01-01

    We examined associations between thyroid condition, gonadal sex and pubertal development in zebrafish. Seventy-two-hour postfertilization larvae were reared in untreated medium or in the presence of goitrogens (sodium perchlorate, 0.82 mM; methimazole, 0.15 and 0.3 mM) or thyroxine (1 and 10 nM) for 30 days. Thyrocyte height, gonadal sex and gonadal development were histologically determined at 45 and 60 days postfertilization (dpf). Thyrocyte hypertrophy, an index of hypothyroidism, was observed at 45 and 60 dpf in perchlorate-treated but only at 45 dpf in methimazole-treated fish. Similarly, gonadal sex ratios were biased toward ovaries relative to control animals at 45 and 60 dpf in perchlorate-treated fish but only at 45 dpf in methimazole-treated fish. Gonadal sex ratios were biased toward testes at 45 and 60 dpf in thyroxine-treated fish. Spermatogenesis was delayed in testes from goitrogen-treated fish at 60 dpf relative to control values, but was unaffected in testes from thyroxine-treated individuals. Oogenesis seemed to be nonspecifically delayed in all treatments relative to control at 60 dpf. This study confirmed the previously reported association between hypothyroid condition and ovarian-skewed ratios, and hyperthyroid condition and testicular-skewed ratios, and also showed that male pubertal development is specifically delayed by experimental hypothyroidism. The simultaneous recovery from the hypothyroid and ovary-inducing effects of methimazole by 60 dpf (27 days post-treatment) suggests that the ovary-skewing effect of goitrogens is reversible when thyroid conditions return to basal levels before developmental commitment of gonadal sex. Conversely, the masculinizing effect of hyperthyroidism seems to be stable and perhaps permanent.

  14. Regulation of gonadal sex ratios and pubertal development by the thyroid endocrine system in zebrafish (Danio rerio).

    Science.gov (United States)

    Sharma, Prakash; Patiño, Reynaldo

    2013-04-01

    We examined associations between thyroid condition, gonadal sex and pubertal development in zebrafish. Seventy-two-hour postfertilization larvae were reared in untreated medium or in the presence of goitrogens (sodium perchlorate, 0.82 mM; methimazole, 0.15 and 0.3 mM) or thyroxine (1 and 10 nM) for 30 days. Thyrocyte height, gonadal sex and gonadal development were histologically determined at 45 and 60 days postfertilization (dpf). Thyrocyte hypertrophy, an index of hypothyroidism, was observed at 45 and 60 dpf in perchlorate-treated but only at 45 dpf in methimazole-treated fish. Similarly, gonadal sex ratios were biased toward ovaries relative to control animals at 45 and 60 dpf in perchlorate-treated fish but only at 45 dpf in methimazole-treated fish. Gonadal sex ratios were biased toward testes at 45 and 60 dpf in thyroxine-treated fish. Spermatogenesis was delayed in testes from goitrogen-treated fish at 60 dpf relative to control values, but was unaffected in testes from thyroxine-treated individuals. Oogenesis seemed to be nonspecifically delayed in all treatments relative to control at 60 dpf. This study confirmed the previously reported association between hypothyroid condition and ovarian-skewed ratios, and hyperthyroid condition and testicular-skewed ratios, and also showed that male pubertal development is specifically delayed by experimental hypothyroidism. The simultaneous recovery from the hypothyroid and ovary-inducing effects of methimazole by 60 dpf (27 days post-treatment) suggests that the ovary-skewing effect of goitrogens is reversible when thyroid conditions return to basal levels before developmental commitment of gonadal sex. Conversely, the masculinizing effect of hyperthyroidism seems to be stable and perhaps permanent.

  15. Sex-dependent consequences of pre-pubertal gonadectomy: Social behavior, stress and ethanol responsivity.

    Science.gov (United States)

    Kim, Esther U; Spear, Linda P

    2016-01-01

    Alcohol consumption can be enhanced or moderated by sensitivity to its aversive and appetitive properties, including positive social outcomes. These differences emerge post-pubertally, suggesting a potential role of gonadal hormones. To determine the role of gonadal hormones in sensitivity to the social impairing and social context-related attenuations in the aversive effects of ethanol, prepubertal male and female rats were gonadectomized (GX) or sham (SH) operated on postnatal day (P) 25, or left non-manipulated (NM). In adulthood (P70), rats were restrained for 90 min prior to challenge with 0.0 or 1.0 g/kg ethanol and social interaction (SI) testing. At P77, groups of 4 same-sex littermates from the same surgical condition were given access to a supersaccharin (SS) solution (3% sucrose, 0.125% saccharin), followed by an intraperitoneal injection of ethanol (0.0, 0.50, 1.0, 1.5 g/kg). Intakes of SS were examined 24h later for expression of conditioned taste aversions. Acute stress prior to SI testing increased frequency of play fighting in both sexes, whereas there were no GX effects on this measure, social investigation nor contact. GX, however, decreased baseline social preference (a social anxiety-like effect) in males, while inducing anxiolytic-like increases in baseline social preference in females. The social drinking test revealed that females developed ethanol conditioned taste aversions at a lower dose relative to males, regardless of surgical condition. These findings suggest a potential role for gonadal hormones in moderating social-anxiety like behaviors but not sensitivity to the social impairing effects of ethanol or ethanol's aversive consequences in a social context.

  16. Effective Feature Preprocessing for Time Series Forecasting

    DEFF Research Database (Denmark)

    Zhao, Junhua; Dong, Zhaoyang; Xu, Zhao

    2006-01-01

    Time series forecasting is an important area in data mining research. Feature preprocessing techniques have significant influence on forecasting accuracy, therefore are essential in a forecasting model. Although several feature preprocessing techniques have been applied in time series forecasting......, there is so far no systematic research to study and compare their performance. How to select effective techniques of feature preprocessing in a forecasting model remains a problem. In this paper, the authors conduct a comprehensive study of existing feature preprocessing techniques to evaluate their empirical...... performance in time series forecasting. It is demonstrated in our experiment that, effective feature preprocessing can significantly enhance forecasting accuracy. This research can be a useful guidance for researchers on effectively selecting feature preprocessing techniques and integrating them with time...

  17. Time Rate Gradient Effects and Negative Mass

    Science.gov (United States)

    Miksch, Edmond

    2008-03-01

    The Harvard tower Experiment and tests with accurate atomic clocks show that a clock at a high elevation indicates more elapsed time than a clock at a low elevation, both clocks properly measuring time at their locations. This fact mandates that Newton's first law of motion be rewritten to cite impulse balance rather than force balance. Time rate gradient effects explain how the weight of a precisely vertical and precisely uniform electric field or a precisely vertical and precisely uniform magnetic field is supported in a precisely unidirectional gravitational field. Time rate gradient effects also explain how the weight of a unidirectional gravitational field is reacted. It is confirmed that the mass density of the gravitational field is negative. http://www.TimeRateGradient.com; http://www.Negative-Mass.com; http://www.EinsteinsElevator.com

  18. Effects of acute and chronic caffeine on risk-taking behavior in children and adolescents.

    Science.gov (United States)

    Temple, Jennifer L; Ziegler, Amanda M; Graczyk, Adam M; Crandall, Amanda

    2017-05-01

    Consumption of caffeinated beverages is associated with increased risk-taking behavior. The purpose of this study was to determine if acute caffeine administration influences risk-taking behavior in a dose-dependent manner. Participants were pre- (ages 8-9) and post-pubertal (ages 15-17) children who visited the laboratory three times and consumed a beverage containing 0, 1, or 2 mg/kg of caffeine. Thirty minutes later, participants completed the balloon analogue risk task (BART), the Iowa gambling task (IGT), and a delay discounting task. The number of balloons exploded on the BART task was significantly increased after 2 mg/kg of caffeine in moderate caffeine consumers, but was decreased after 2 mg/kg of caffeine in high caffeine consumers. There were no main effects of caffeine dose on the delay discounting task or on the IGT. Post-pubertal participants showed reduced delay discounting compared with pre-pubertal participants. Finally, average daily caffeine use was significantly, positively correlated with scores on a risk-taking questionnaire. These data suggest that caffeine dose-dependently influences decision making and risk taking. More research is needed to determine the mechanism of this difference as well as the extent to which sex and pubertal phase influence these relationships.

  19. Pubertal Development, Choice of Friends, and Smoking Initiation among Adolescent Males

    Science.gov (United States)

    Drapela, Laurie A.; Gebelt, Janet L.; McRee, Nick

    2006-01-01

    Prior research has indicated that pubertal development and peer associations are important determinants of adolescent smoking behavior. However, more remains to be learned about "why" these variables matter or how they may be related to one another in ways that lead to the initiation of smoking. Using contractual data from the National…

  20. Brief Report: Fathers' and Mothers' Marital Relationship Predicts Daughters' Pubertal Development Two Years Later

    Science.gov (United States)

    Saxbe, Darby E.; Repetti, Rena L.

    2009-01-01

    Parents of 50 4th grade girls reported on their marital relationships and then, two years later, rated their daughters' pubertal development. Fathers' ratings of marital dissatisfaction, mothers' ratings of less emotional support from husbands, and both parents' ratings of aversive marital conflict were correlated with more advanced pubertal…

  1. Insulin resistance in obese pre-pubertal children: Relation to body composition

    Directory of Open Access Journals (Sweden)

    Heba Elsedfy

    2014-07-01

    Conclusion: Dysglycaemia and dyslipidaemia are common among pre-pubertal obese children. Insulin sensitivity indices based on OGTT are superior to fasting indices in identifying at risk children. OGTT should be included in assessing obese children with BMI > 2 SDS. DXA scanning has limited value for this purpose in clinical settings.

  2. Serum inhibin B concentrations in pubertal boys conceived by ICSI: first results

    NARCIS (Netherlands)

    F. Belva; M. Bonduelle; R.C. Painter; J. Schiettecatte; P. Devroey; J. de Schepper

    2010-01-01

    Currently, no published data exist about the gonadal function of children born after ICSI. To evaluate potential risk of testicular seminal dysfunction in boys born to fathers with compromised spermatogenesis, serum inhibin B (as a marker for spermatogenesis) was assessed. We recruited 50 pubertal a

  3. Salivary testosterone concentrations in pubertal ICSI boys compared with spontaneously conceived boys

    NARCIS (Netherlands)

    F. Belva; M. Bonduelle; J. Schiettecatte; H. Tournaye; R.C. Painter; P. Devroey; J. de Schepper

    2011-01-01

    BACKGROUND: To date, no data exist about Leydig cell function of pubertal boys born after ICSI. To evaluate a potential risk of gonadal dysfunction in children born from fathers with compromised fertility, testicular function was assessed by the measurement of salivary testosterone. METHODS: Morning

  4. Identification of various testicular cell populations in pubertal and adult cockerels

    Science.gov (United States)

    Precise identification of the male germinal stem cell population is important for their practical use in programs dedicated to the integration of exogenous genetic material in testicular tissues. In the present study, our aim was to identify germinal cell populations in the testes of pubertal and ad...

  5. Elevated serum IGF-I, but unaltered sex steroid levels, in healthy boys with pubertal gynaecomastia

    DEFF Research Database (Denmark)

    Mieritz, Mikkel G; Sorensen, Kaspar; Aksglaede, Lise

    2014-01-01

    of 501 healthy Danish school boys (aged 6·1-19·8 year) from the COPENHAGEN Puberty Study. MEASUREMENTS: Anthropometry and pubertal stages (PH1-6 and G1-5) were evaluated, and the presence of gynaecomastia was assessed. Body fat percentage was calculated by means of four skin folds and impedance...

  6. Serum AMH levels are lower in healthy boys who develop pubertal gynaecomastia

    DEFF Research Database (Denmark)

    Mieritz, Mikkel G.; Hagen, Casper P.; Almstrup, Kristian

    2015-01-01

    Background: Pubertal gynaecomastia is thought to be a clinical sign of an oestrogen-androgen imbalance, affecting up to 60% of boys. In most cases no underlying endocrinopathy can be identified. In boys, Anti-mullerian hormone (AMH) is produced by immature Sertoli cells and circulating level decr...

  7. Associations between socio-demographic characteristics and pubertal status with disordered eating among primary school children in Selangor, Malaysia.

    Science.gov (United States)

    Chong, Lin Siew; Chin, Yit Siew; Gan, Wan Ying; Nasir, Mohd Taib Mohd

    2017-03-01

    To determine the associations between socio-demographic characteristics and pubertal status with disordered eating among primary school children. Using a stratified multi-stage sampling, a total of 816 children (282 boys and 534 girls) aged 10 to 11 years from 12 selected primary schools in the state of Selangor, participated in this study. Data were collected on socio-demographic characteristics, pubertal status and disordered eating behaviors. The Pubertal Development Scale and the Children's Eating Attitudes Test (ChEAT) were used to assess pubertal status and disordered eating, respectively. Logistic regression analysis was conducted to determine the risk factors of disordered eating. The prevalence of disordered eating was 30.8% (32.8% in boys and 29.7% in girls). However, the sex difference in the prevalence was not statistically significant. Age, ethnicity and pubertal status were significantly associated with disordered eating in univariate logistic regression analysis. Multivariate logistic regression analysis showed that among boys, being either in an advanced or post-pubertal stage (adjusted OR=8.64) and older age group (adjusted OR=2.03) were risk factors of disordered eating. However, among girls, being a Malay (adjusted OR=3.79) or Indian (adjusted OR=5.04) in an advanced or post-pubertal stage (adjusted OR=2.34) and older age group (adjusted OR=1.53) were risk factors of disordered eating. This study found one in three children had disordered eating. Since ethnicity and pubertal status were identified as risk factors, ethnicity-specific intervention programs on the prevention of disordered eating among children should take into consideration their pubertal status.

  8. Parathyroid hormone levels in pubertal uremic adolescents treated with growth hormone.

    Science.gov (United States)

    Picca, Stefano; Cappa, Marco; Martinez, Chiara; Moges, Seyoum Ido; Osborn, John; Perfumo, Francesco; Ardissino, Gianluigi; Bonaudo, Roberto; Montini, Giovanni; Rizzoni, Gianfranco

    2004-01-01

    We have previously described severe hyperparathyroidism during the pubertal growth spurt in three uremic adolescents treated with recombinant human growth hormone (rhGH). Here we investigate the possible role of puberty in the genesis of hyperparathyroidism during rhGH treatment of a large cohort of patients. Data from 67 uremic patients treated with rhGH from five Italian pediatric nephrology centers were retrospectively recorded every 3 months starting 1 year before rhGH administration. The mean (+/-SD) rhGH treatment observation period was 19.9+/-5.9 months. The mean age at the start of rhGH treatment was 8.3+/-3.6 years. Of the 67 patients, 15 reached pubertal stage 2 during the 1st year of rhGH treatment and 12 of these 15 progressed to pubertal stage 3. The relative increase in parathyroid hormone (PTH) levels after rhGH initiation was greater in pubertal [1.95, 95% confidence interval (CI) 1.43-2.66] than in prepubertal patients (1.19, 95% CI 1.01-1.40). Increases in PTH levels were significantly different between the two groups (Delta=1.64, 95% CI 1.16-3.19, P=0.007). Multiple regression analysis showed an inverse correlation between PTH and calcium levels and a positive correlation between PTH and pubertal stage 3. There was no correlation with phosphate levels and calcitriol dosage. In conclusion, these results suggest that in uremic adolescents treated with rhGH puberty may influence PTH levels.

  9. Time Transient Effects in Superconducting Magnets

    CERN Document Server

    AUTHOR|(CDS)2051280; Russenschuck, Stephan; Palumbo, Luigi

    2004-01-01

    The subject of this thesis is the study of time transient effects in super- conducting cables, with applications to accelerator magnets, and the development of a simulation code. The superconducting cables are modeled at the strand level as a lumped resistor, inductor generator circuit. The analysis in time domain of the circuit currents discloses the transient effects. The code developed can solve Rutherford type cable of any size, shape geometry under any exciting external field. The code has been implemented in Roxie where it is used to compute ramp dependent field error and heat losses.

  10. Time resolved spin Seebeck effect experiments

    OpenAIRE

    Roschewsky, Niklas; Schreier, Michael; Kamra, Akashdeep; Schade, Felix; Ganzhorn, Kathrin; Meyer, Sibylle; Huebl, Hans; Geprägs, Stephan; Gross, Rudolf; Goennenwein, Sebastian T. B.

    2013-01-01

    In this Letter, we present the results of transient thermopower experiments, performed at room temperature on yttrium iron garnet/platinum bilayers. Upon application of a time-varying thermal gradient, we observe a characteristic low-pass frequency response of the ensuing thermopower voltage with cutoff frequencies of up to 37 MHz. We interpret our results in terms of the spin Seebeck effect, and argue that small wavevector magnons are of minor importance for the spin Seebeck effect in our th...

  11. Growth hormone mediates pubertal skeletal development independent of hepatic IGF-1 production.

    Science.gov (United States)

    Courtland, Hayden-William; Sun, Hui; Beth-On, Mordechay; Wu, Yingjie; Elis, Sebastien; Rosen, Clifford J; Yakar, Shoshana

    2011-04-01

    Deficiencies in either growth hormone (GH) or insulin-like growth factor 1 (IGF-1) are associated with reductions in bone size during growth in humans and animal models. Liver-specific IGF-1-deficient (LID) mice, which have 75% reductions in serum IGF-1, were created previously to separate the effects of endocrine (serum) IGF-1 from autocrine/paracrine IGF-1. However, LID mice also have two- to threefold increases in GH, and this may contribute to the observed pubertal skeletal phenotype. To clarify the role of GH in skeletal development under conditions of significantly reduced serum IGF-1 levels (but normal tissue IGF-1 levels), we studied the skeletal response of male LID and control mice to GH inhibition by pegvisomant from 4 to 8 weeks of age. Treatment of LID mice with pegvisomant resulted in significant reductions in body weight, femur length (Le), and femur total area (Tt.Ar), as well as further reductions in serum IGF-1 levels by 8 weeks of age, compared with the mean values of vehicle-treated LID mice. Reductions in both Tt.Ar and Le were proportional after treatment with pegvisomant. On the other hand, the relative amount of cortical tissue formed (RCA) in LID mice treated with pegvisomant was significantly less than that in both vehicle-treated LID and control mice, indicating that antagonizing GH action, either directly (through GH receptor signaling inhibition) or indirectly (through further reductions in serum/tissue IGF-1 levels), results in disproportionate reductions in the amount of cortical bone formed. This resulted in bones with significantly reduced mechanical properties (femoral whole-bone stiffness and work to failure were markedly decreased), suggesting that compensatory increases of GH in states of IGF-1 deficiency (LID mice) act to protect against a severe inhibition of bone modeling during growth, which otherwise would result in bones that are too weak for normal and/or extreme loading conditions.

  12. Retrospective cohort study of relationship between pubertal growth spurt and body mass index%围青春期体脂与青春发动时相关系的回顾性队列研究

    Institute of Scientific and Technical Information of China (English)

    张珊; 史慧静; 杨鞭; 张越

    2011-01-01

    Objective To examine peri-pubertal body mass index ( BMI) in relation to pubertal timing, as asseased by age at onset of pubertal growth spurt ( AOGS) and at peak height velocity ( APHV ), among children and adolescents. Methods A cluster sample of 329 nine-grade students was selected from 3 schools in Shanghai. For each subject, annual measurements of height and weight from grade one to grade nine were obtained from school health record. Age at OGS and PHV, criterion for pubertal timing, were calculated by using the cubic spline fit function. Results Advanced pubertal growth spurt was estimated by using P67 of peak height velocity of pubertal growth. BMI -Z score at pre-puberty, early puberty,and middle/late puberty were analyzed in relation to pubertal timing. The increments of BMI - Z score during pre-puberty to early puberty and during early to middle/late puberty were compared between advanced and non-advanced pubertal timing groups. Results In both of girls and boys, advanced growth spurt was associated with higher BMI -Z scores in pre-puberty, early puberty and middle/late puberty. Advanced growth spurt was significantly associated with greater increment of BMI -Z scores during pre-puberty to early puberty, which is not found in boys. Conclusion Higher level of BMI in pre-puberty and greater increments of BMI - Z score during pre-puberty to early puberty may predict advance growth spurt in adolescence as well as adulthood.%目的 研究不同青春发动时相的儿童青少年在围青春期的体脂水平及增长模式,为青春发动机制的研究和肥胖防控工作提供依据.方法 整群选择上海市3所学校的329名九年级学生,回溯一~九年级时的身高和体重体检记录,用Cubic Spline Fit函数拟合得到身高突增启动年龄和身高突增高峰年龄,并以此为青春发动时相界定的依据,分析围青春期不同阶段体质量指数(BMI)-Z值和BMI-Z增加值与青春发动时相的关系.结果 女生青春发

  13. Time resolved spin Seebeck effect experiments

    Energy Technology Data Exchange (ETDEWEB)

    Roschewsky, Niklas, E-mail: niklas.roschewsky@wmi.badw.de; Schreier, Michael; Schade, Felix; Ganzhorn, Kathrin; Meyer, Sibylle; Geprägs, Stephan [Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Kamra, Akashdeep [Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Kavli Institute of Nanoscience, Delft University of Technology, Delft (Netherlands); Huebl, Hans; Goennenwein, Sebastian T. B. [Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Nanosystems Initiative Munich (NIM), Munich (Germany); Gross, Rudolf [Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Physik-Department, Technische Universität München, Garching (Germany); Nanosystems Initiative Munich (NIM), Munich (Germany)

    2014-05-19

    In this Letter, we present the results of transient thermopower experiments, performed at room temperature on yttrium iron garnet/platinum bilayers. Upon application of a time-varying thermal gradient, we observe a characteristic low-pass frequency response of the ensuing thermopower voltage with cutoff frequencies of up to 37 MHz. We interpret our results in terms of the spin Seebeck effect, and argue that small wavevector magnons are of minor importance for the spin Seebeck effect in our thin film hybrid structures.

  14. Facing changes and changing faces in adolescence: a new model for investigating adolescent-specific interactions between pubertal, brain and behavioral development.

    Science.gov (United States)

    Scherf, K Suzanne; Behrmann, Marlene; Dahl, Ronald E

    2012-04-01

    Adolescence is a time of dramatic physical, cognitive, emotional, and social changes as well as a time for the development of many social-emotional problems. These characteristics raise compelling questions about accompanying neural changes that are unique to this period of development. Here, we propose that studying adolescent-specific changes in face processing and its underlying neural circuitry provides an ideal model for addressing these questions. We also use this model to formulate new hypotheses. Specifically, pubertal hormones are likely to increase motivation to master new peer-oriented developmental tasks, which will in turn, instigate the emergence of new social/affective components of face processing. We also predict that pubertal hormones have a fundamental impact on the re-organization of neural circuitry supporting face processing and propose, in particular, that, the functional connectivity, or temporal synchrony, between regions of the face-processing network will change with the emergence of these new components of face processing in adolescence. Finally, we show how this approach will help reveal why adolescence may be a period of vulnerability in brain development and suggest how it could lead to prevention and intervention strategies that facilitate more adaptive functional interactions between regions within the broader social information processing network. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. Risk assessment for changes in the metabolic profile and body weights of pre-pubertal gilts during long-term monotonic exposure to low doses of zearalenone (ZEN).

    Science.gov (United States)

    Gajęcka, Magdalena; Tarasiuk, Michał; Zielonka, Łukasz; Dąbrowski, Michał; Gajęcki, Maciej

    2016-12-01

    The aim of the study was to examine whether the process of exposure to low doses of ZEN generates changes in the hematological and biochemical image of blood serum. During the experiment, pre-pubertal gilts (up to 25kg) were administered per os ZEN at a dose of 40μg/kg BW (Group E, n=18) or placebo (Group C, n=21) on a daily basis for 42days. Blood samples for investigation were collected seven times at intervals of one week. In the experimental groups, slight but statistically significant changes in the values of selected biochemical blood indices such as glucose, ALT, Pin, total protein and Fe, or in hematological indices such as RBC, MCV, PLT, WBC, basophils, eosinophils and monocytes were observed. Based on statistical analysis between the groups, differences in the values of WBC, basophils, peroxidase negative cells, Hb, Ht, MCV, HDW, glucose, ALT, AP, total protein, iron or potassium were found. In Group E, decreasing trends in the values of PLT and glucose, and increasing trends in the values of total protein, Pin, Na and Cl were found. The described situations occurred during the last three weeks of exposure. Low levels of exposure to ZEN lead to completely different changes in the metabolic profile than those resulting from higher doses of the toxin. The stimulatory effect of mycotoxins, observed in initial stages of exposure, is eliminated when the compensatory response and adaptive mechanisms are triggered, and due to excessive loss of energy, which may point to more efficient feed utilization and/or detoxification processes. The values of body weight gain obtained in Group E were monotonically higher in four out of the six investigated weeks of exposure. The above changes were accompanied by a decrease in glucose concentrations and higher total protein levels (a rising tendency), which could have affected the rate of body weight gain. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Giant fibroadenoma of the breast in a pre-pubertal girl: a case report

    Directory of Open Access Journals (Sweden)

    Sunder Goyal

    2014-02-01

    Full Text Available Juvenile fibroadenoma comprises about 4% of the total fibroadenomas. The incidence of giant juvenile fibroadenomas is merely 0.5% of all the fibroadenomas. Bilateral giant juvenile fibroadenomas are extremely rare. We are presenting a case of giant juvenile fibroadenomas in an 11-year-old pre-pubertal girl. The diagnosis was made on fine-needle aspiration cytology which was confirmed on histopathology. As these tumors are mostly benign, breast-conserving surgery is done so that patient can lead a normal life without psychological trauma.-----------------------------------Cite this article as: Goyal S, Garg G, Narang S. Giant fibroadenoma of the breast in a pre-pubertal girl: a case report. Int J Cancer Ther Oncol 2014; 2(1:020113.DOI: http://dx.doi.org/10.14319/ijcto.0201.13

  17. Pubertal Progression and Reproductive Hormones in Healthy Girls With Transient Thelarche

    DEFF Research Database (Denmark)

    Johansen, Marie Lindhardt; Hagen, Casper P.; Mieritz, Mikkel G.

    2017-01-01

    Context: Detailed evaluation of pubertal progression in girls from longitudinal studies is sparse, and the phenomenon of transient thelarche (TT), defined as the appearance, regression, and subsequent reappearance of breast buds, in healthy girls remains undescribed. Objective: To describe TT...... girls) followed longitudinally as part of the COPENHAGEN Puberty Study were included in the evaluation of TT. A total of 1466 girls from 2 cross-sectional studies were included in the creation of the puberty nomograms. Intervention(s): None. Main Outcome Measure(s): Pubertal progression, specifically...... thelarche, reproductive hormones, genotype, and growth. Results: Twelve of 98 (12%) girls experienced TT. A larger proportion of girls with TT entered puberty by the pubarche pathway (50%) compared with girls with normal progression (15.4%), P = 0.014. Girls with TT progressed through puberty normally when...

  18. Impact of socio-emotional context, brain development, and pubertal maturation on adolescent risk-taking.

    Science.gov (United States)

    Smith, Ashley R; Chein, Jason; Steinberg, Laurence

    2013-07-01

    While there is little doubt that risk-taking is generally more prevalent during adolescence than before or after, the underlying causes of this pattern of age differences have long been investigated and debated. One longstanding popular notion is the belief that risky and reckless behavior in adolescence is tied to the hormonal changes of puberty. However, the interactions between pubertal maturation and adolescent decision making remain largely understudied. In the current review, we discuss changes in decision making during adolescence, focusing on the asynchronous development of the affective, reward-focused processing system and the deliberative, reasoned processing system. As discussed, differential maturation in the structure and function of brain systems associated with these systems leaves adolescents particularly vulnerable to socio-emotional influences and risk-taking behaviors. We argue that this asynchrony may be partially linked to pubertal influences on development and specifically on the maturation of the affective, reward-focused processing system.

  19. A Matter of Time: The Effects of Time on Learning

    Science.gov (United States)

    Kidd, Debra

    2014-01-01

    This article looks at how time might be viewed differently in the classroom, drawing on the philosophy of Gilles Deleuze in order to frame the exploration. It asks how teachers might become more attuned to difference, uncertainty and possibility in their classrooms and questions the wisdom of viewing the learning process in linear ways. The…

  20. Minor sperm abnormalities in young male post-pubertal patients with juvenile dermatomyositis

    Directory of Open Access Journals (Sweden)

    A.J.P. Moraes

    2008-12-01

    Full Text Available The objective of the present study was to identify sperm abnormalities in young male patients with juvenile dermatomyositis (JDM. In 2005, 18 male JDM patients, diagnosed according to the criteria of Bohan and Peter, were followed at the Pediatric Rheumatology Unit and Rheumatology Division, of our Institution. Of the 18 males, 11 were pre-pubertal and 7 were post-pubertal. Two of 7 post-pubertal JDM male patients were excluded: one for orchidopexy for cryptorchidism and the other for testicular ectopia in the left testis. The remaining 5 post-pubertal JDM patients were prospectively evaluated on the basis of two semen analyses, according to the World Health Organization (WHO, urologic evaluation, testicular Doppler ultrasound hormone profile. The data of the JDM patients were compared with those of 5 age-matched healthy controls. The median age 18, was similar in JDM patients and controls. All JDM patients had teratozoospermia (abnormal sperm morphology, as did 4 (80% of the controls. One of JDM patients had previous oligoasthenoteratozoospermia treated with intravenous cyclophosphamide with normalization of the number and concentration of the sperm after 5 years. All sperm parameters (sperm concentration, total sperm count and total motile sperm count by WHO, and sperm morphology by Kruger strict criteria, testicular volumes by Prader orchidometer and ultrasound, and hormones were similar in JDM patients compared with controls. The frequency of anti-sperm antibodies was similar in both groups. All JDM patients had minor sperm abnormalities in the head, midpiece, and/or tail of spermatozoids. Serial semen analyses in larger study populations are necessary to identify the extent and duration of sperm abnormalities in male patients with idiopathic inflammatory myopathies.

  1. Association of body mass index with lung function in pre- pubertal girls in Vadodara District

    Directory of Open Access Journals (Sweden)

    Rajeshri K Bodat

    2015-09-01

    Full Text Available Introduction: Among the various investigations available, pulmonary function test (PFT is a one of the important tool for the assessment of pulmonary function. There must be differences in reference values in India between different state, different region for spirometric parameters. Methodology: The present study was conducted among normal healthy pre pubertal girl in Vadodara region. The study was conducted among pre pubertal girls (10-12 yrs. Standard anthropometric measurements weight (kg, height (cm, was measured in a beam balance. Minimum three readings were given and best of the three was chosen for analysis, based on standardization of spirometry study based on ATS/ERS task force series and various other studies. Results: Mean age of the participants was 11.36 (+/-0.69 years. Similarly mean height, weight, BMI and BSA was 134.8(+/-8.91 cm, 28(+/-5.9 kg, 15.29(+/-2.02 (Kg/m2, and 1.02(+/-0.13 (m2 respectively. There were 27(60 % participants with BMI 18. There was significant statistical association between BMI and FEV1 (%, FEV1/FVC (%, PEFR (% (P < 0.05. Conclusion: There is significant relation between pulmonary function and BMI in pre pubertal girls. As BMI increase lung function tends to be decrease as compared to those who have low BMI. [Natl J Med Res 2015; 5(3.000: 256-258

  2. Pre-pubertal males practising Taekwondo exhibit favourable postural and neuromuscular performance.

    Science.gov (United States)

    Jlid, Mohamed Chedly; Maffulli, Nicola; Souissi, Nisar; Chelly, Mohamed Souheil; Paillard, Thierry

    2016-01-01

    The postural and neuromuscular performances in healthy children taekwondo (TKD) practitioners in comparison with control children were examined. Seventeen healthy pre-pubertal males undertaking only physical education at school (age: 11.88 ± 0.33 years) and 12 pre-pubertal male TKD practitioners (>3 years, 4 sessions a week) (age 11.66 ± 0.49 years) were recruited. Performances in the dynamic postural control (Star Excursion Balance Test -SEBT), vertical jump [squat jump (SJ) and countermovement jump (CMJ)] and sprint running (distances: 5, 10, 20 and 30 m) tests were compared between the two groups. The performances of the TKD practitioners were better than those of the non-TKD active for the SEBT (for 14 of 16 conditions, p  0.05). TKD practice would stimulate sensory input and motor output of the postural system that would enhance its efficiency. In addition, the dynamic nature of TKD would develop the muscle power of the lower limbs. In our sample of healthy pre-pubertal males, TKD appears to improve postural and neuromuscular functions, but further research is required.

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

    Science.gov (United States)

    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.

  4. Mutational Analysis of TAC3 and TACR3 Genes in Patients with Idiopathic Central Pubertal Disorders

    Science.gov (United States)

    Tusset, Cintia; Noel, Sekoni D.; Trarbach, Ericka B.; Silveira, Letícia F. G.; Jorge, Alexander A. L.; Brito, Vinicius N.; Cukier, Priscila; Seminara, Stephanie B.; de Mendonça, Berenice B.; Kaiser, Ursula B.; Latronico, Ana Claudia

    2013-01-01

    Aim To investigate the presence of variants in the TAC3 and TACR3 genes, which encode NKB and its receptor (NK3R), respectively, in a large cohort of patients with idiopathic central pubertal disorders. Patients and Methods Two hundred and thirty seven patients were studied: 114 with central precocious puberty (CPP), 73 with normosmic isolated hypogonadotropic hypogonadism (IHH) and 50 with constitutional delay of growth and puberty (CDGP). The control group consisted of 150 Brazilian individuals with normal pubertal development. Genomic DNA was extracted from peripheral blood and the entire coding region of both TAC3 and TACR3 genes were amplified and automatically sequenced. Results We identified one variant (p.A63P) in NKB and four variants, p.G18D, p.L58L (c.172C>T), p.W275* and p.A449S in NK3R, which were absent in the control group. The p.A63P variant was identified in a girl with CPP, and p.A449S in a girl with CDGP. The known p.G18D, p.L58L and p.W275* variants were identified in three unrelated males with normosmic IHH. Conclusion Rare variants in the TAC3 and TACR3 genes were identified in patients with central pubertal disorders. Loss-of-function variants of TACR3 were associated with the normosmic IHH phenotype. PMID:23329188

  5. [Contribution of anthropometric characteristics to pubertal stage prediction in young male individuals].

    Science.gov (United States)

    Medeiros, Radamés Maciel Vitor; Arrais, Ricardo Fernando; de Azevedo, Jenner Chrystian Veríssimo; do Rêgo, Jeferson Tafarel Pereira; de Medeiros, Jason Azevedo; de Andrade, Ricardo Dias; Dantas, Paulo Moreira Silva

    2014-09-01

    To identify the contribution of anthropometric variables to predict the maturational stage in young males. Cross-sectional study that enrolled 190 male subjects aged between eight and 18 years, randomly selected from public and private schools in Natal, Northeast Brazil. Thirty-two anthropometric variables were measured following the recommendations of the International Society for the Advancement of Kineanthropometry (ISAK). The assessment of sexual maturation was based on the observation of two experienced experts, who identified the pubertal development according to Tanner guidelines (1962). The anthropometric variables showed a significant increase of their values during the advancement of pubertal development (p<0.05). The following variables showed the best value for prediction of maturational groups: sitting height, femoral biepicondylar diameter, forearm girth, triceps skinfold, tibiale laterale and acromiale-radiale bone lenghts. These variables were able to estimate the pubertal stages in 76.3% of the sujects. The anthropometric characteristics showed significant differences between the moments of maturational stages, being found, representatively, seven variables that best predict the stages of sexual maturation. Copyright © 2014 Sociedade de Pediatria de São Paulo. Publicado por Elsevier Editora Ltda. All rights reserved.

  6. Growth, pubertal development, skeletal maturation and bone mass acquisition in athletes.

    Science.gov (United States)

    Georgopoulos, Neoklis A; Markou, Kostas B; Theodoropoulou, Anastasia; Vagenakis, George A; Mylonas, Panagiotis; Vagenakis, Apostolos G

    2004-01-01

    The genetic potentials for growth can be fully expressed only under favourable environmental conditions. Excessive physical training may negatively affect growth, especially during puberty. Sports that require a strict control of energy input in the presence of a high energy output are of particular concern. In gymnastics, a different pattern in skeletal maturation was observed, leading to an attenuation of growth potential ins Artistic Gymnasts (AG), more pronounced in males than in females, whereas in female Rhythmic Gymnasts (RG) the genetic predisposition to growth was preserved because of a late catch-up growth phenomenon. In all other sports not requiring strict dietary restrictions, no deterioration of growth has been documented. Intensive physical training and negative energy balance modify the hypothalamic pituitary set point at puberty, prolong the prepubertal stage and delay pubertal development and menarche in a variety of sports. In elite RG and AG the prepubertal stage is prolonged and pubertal development is entirely shifted to a later age, paralleling the bone age rather than the chronological age. Bone formation, and, consequently, BMD are enhanced by physical activity. In athletes, high-impact loading activities have been shown to improve BMD, while in sports requiring a lean somatotype, the delay in skeletal maturation and pubertal development, resulting from hypoestrogenemia, predisposes athletes to osteopenia. In AG, an increase in bone density is observed using the bone age as denominator.

  7. A Reevaluation of the Question: Is the Pubertal Resurgence in Pulsatile GnRH Release in the Male Rhesus Monkey (Macaca mulatta) Associated With a Gonad-Independent Augmentation of GH Secretion?

    Science.gov (United States)

    Shahab, M; Trujillo, M Vargas; Plant, T M

    2015-10-01

    A somatic signal has been posited to trigger the pubertal resurgence in pulsatile GnRH secretion that initiates puberty in highly evolved primates. That GH might provide such a signal emerged in 2000 as a result of a study reporting that circulating nocturnal GH concentrations in castrated juvenile male monkeys increased in a 3-week period immediately preceding the pubertal resurgence of LH secretion. The present study was conducted to reexamine this intriguing relationship, again in an agonadal model. Four castrated juvenile male monkeys were implanted with indwelling jugular catheters, housed in remote sampling cages, and subjected to 24 hours of sequential blood sampling (every 30 min) every 2 weeks from 19.5 to 22 months of age. Twenty-four-hour profiles of circulating GH concentrations were analyzed using the pulse detection algorithm, PULSAR, and developmental changes in pulsatile GH release with respect to the initiation of the pubertal rise of LH secretion (week 0; observed between 22.5 and 32 mo of age) were examined for significance by a repeated-measures ANOVA. Changes in the parameters of pulsatile GH secretion, including mean 24-hour GH concentration and GH pulse frequency and pulse amplitude for 3 (n = 4) and 6 (n = 3) months before week 0 were unremarkable and nonsignificant. These findings fail to confirm those of the earlier study and lead us to conclude that the timing of the pubertal resurgence of GnRH release in the male monkey is not dictated by GH. Reasons for the discrepancy between the two studies are unclear.

  8. Relating Phthalate and BPA Exposure to Metabolism in Peripubescence: The Role of Exposure Timing, Sex, and Puberty.

    Science.gov (United States)

    Watkins, Deborah J; Peterson, Karen E; Ferguson, Kelly K; Mercado-García, Adriana; Tamayo y Ortiz, Marcela; Cantoral, Alejandra; Meeker, John D; Téllez-Rojo, Martha Maria

    2016-01-01

    Exposure to endocrine-disrupting chemicals during development may play a role in the increasing prevalence of metabolic syndrome and type 2 diabetes among children and adolescents by interfering with metabolic homeostasis. To explore associations between in utero and peripubertal urinary phthalate metabolite and bisphenol A (BPA) concentrations and markers of peripubertal metabolic homeostasis. Early Life Exposure in Mexico to Environmental Toxicants (ELEMENT): a longitudinal cohort study of pregnant women in Mexico City and their offspring. Public maternity hospitals in Mexico City. Women recruited during pregnancy; offspring recruited for follow-up at age 8-14 years (n = 250). None. Fasting serum c-peptide, IGF-1, leptin, and glucose concentrations among children at follow-up; calculated measures of insulin secretion and insulin resistance. Phthalate metabolites and BPA were associated with metabolism biomarkers at age 8-14 years in patterns that varied by sex, pubertal status, and exposure timing. For example, in utero monoethyl phthalate was associated with lower insulin secretion among pubertal boys (P = .02) and higher leptin among girls (P = .04). In utero di-2-ethylhexyl phthlate was associated with higher IGF-1 among pubertal girls; peripubertal di-2-ethylhexyl phthlate was associated with higher IGF-1, insulin secretion, and resistance among prepubertal girls. In contrast, peripubertal dibutyl phthalate, monobenzyl phthalate, and mono-3-carboxypropyl phthalate were associated with lower IGF-1 among pubertal boys. Peripubertal BPA was associated with higher leptin in boys (P = .01). Considering the long-term health effects related to metabolic syndrome, additional research on exposure and metabolic outcomes across developmental periods and early adulthood is needed.

  9. Skeletal adaptations associated with pre-pubertal gymnastics participation as determined by DXA and pQCT: a systematic review and meta-analysis.

    Science.gov (United States)

    Burt, Lauren A; Greene, David A; Ducher, Gaele; Naughton, Geraldine A

    2013-05-01

    Participation in gymnastics prior to puberty offers an intriguing and unique model, particularly in girls. The individuality comes from both upper and lower limbs being exposed to high mechanical loading through year long intensive training programs, initiated at a young age. Studying this unique model and the associated changes in musculoskeletal health during growth is an area of specific interest. Previous reviews on gymnastics participation and bone health have been broad; and not limited to a particular maturation period, such as pre-puberty. To determine the difference in skeletal health between pre-pubertal girls participating in gymnastics compared with non-gymnasts. Meta-analysis. Following a systematic search, 17 studies were included in this meta-analysis. All studies used dual-energy X-ray absorptiometry to assess bone mineral density and bone mineral content. In addition, two studies included peripheral quantitative computed tomography. Following the implementation of a random effects model, gymnasts were found to have greater bone properties than non-gymnasts. The largest difference in bone health between gymnasts and non-gymnasts was observed in peripheral quantitative computed tomography-derived volumetric bone mineral density at the distal radius (d=1.06). Participation in gymnastics during pre-pubertal growth was associated with skeletal health benefits, particularly to the upper body. Copyright © 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  10. Dairy intake in relation to breast and pubertal development in Chilean girls.

    Science.gov (United States)

    Gaskins, Audrey J; Pereira, Ana; Quintiliano, Daiana; Shepherd, John A; Uauy, Ricardo; Corvalán, Camila; Michels, Karin B

    2017-05-01

    Background: Frequent dairy consumption in childhood has been related to higher growth-hormone concentrations that may affect mammary gland and pubertal development.Objective: We evaluated the relation of dairy intake to breast composition at Tanner stage 4 and age at menarche.Design: A total of 515 Chilean girls are included in the Growth and Obesity Cohort Study. The subjects have been followed longitudinally since they were 3-4 y old (from 2006 to the present). Starting in 2013, diet was assessed every 6 mo via a 24-h recall. The breast fibroglandular volume (FGV) was measured with the use of dual-energy X-ray absorptiometry at Tanner stage 4. The date of menarche was reported every 6 mo. Our analysis included 290 girls with data on prospective diet and breast composition and 324 girls with data on prospective diet and age at menarche.Results: The mean ± SD breast FGV and percentage of fibroglandular volume (%FGV) (i.e., FGV divided by total breast volume times 100) at Tanner stage 4 was 81.7 ± 32.2 cm(3) and 42.0% ± 16.7%, respectively. Only sweetened, artificially flavored milk-based drinks were associated with the %FGV with girls who consumed >125 g/d having a %FGV that was 4.5% (95% CI: 0.9%, 8.1%) higher than that of girls who consumed none (P-trend = 0.007). Yogurt intake was associated with a lower FGV. Specifically, girls who consumed >125 g yogurt/d had -10.2 cm(3) (95% CI: -20.2, -0.3 cm(3)) less FGV than did girls who consumed no yogurt (P-trend = 0.03). The majority (90.7%) of girls in our cohort attained menarche before the data analyses with a mean ± SD age at menarche of 11.9 ± 0.7 y. In multivariable models, low-fat dairy, low-fat milk, and yogurt intakes were associated with a later age at menarche. In particular, girls who consumed >125 g yogurt/d had menarche, on average, 4.6 mo (95% CI: 1.9, 7.4 mo) later than girls who consumed no yogurt (P-trend = 0.01).Conclusion: More-frequent consumption of sweetened, artificially-flavored milk

  11. Effects of heat acclimation on time perception.

    Science.gov (United States)

    Tamm, Maria; Jakobson, Ainika; Havik, Merle; Timpmann, Saima; Burk, Andres; Ööpik, Vahur; Allik, Jüri; Kreegipuu, Kairi

    2015-03-01

    Cognitive performance is impaired during prolonged exercise in hot environment compared to temperate conditions. These effects are related to both peripheral markers of heats stress and alterations in CNS functioning. Repeated-exposure to heat stress results in physiological adaptations, and therefore improvement in exercise capacity and cognitive functioning are observed. The objective of the current study was to clarify the factors contributing to time perception under heat stress and examine the effect of heat acclimation. 20 young healthy male subjects completed three exercise tests on a treadmill: H1 (at 60% VO(2)peak until exhaustion at 42°C), N (at 22°C; duration equal to H1) and H2 (walk until exhaustion at 42°C) following a 10-day heat acclimation program. Core temperature (T(C)) and heart rate (HR), ratings of perceived fatigue and exertion were obtained continuously during the exercise, and blood samples of hormones were taken before, during and after the exercise test for estimating the prolactin, growth hormone and cortisol response to acute exercise-heat stress. Interval production task was performed before, during and after the exercise test. Lower rate of rise in core temperature, heart rate, hormone response and subjective ratings indicated that the subjects had successfully acclimated. Before heat acclimation, significant distortions in produced intervals occurred after 60 minutes of exercise relative to pre-trial coefficients, indicating speeded temporal processing. However, this effect was absent after in acclimated subjects. Blood prolactin concentration predicted temporal performance in both conditions. Heat acclimation slows down the increase in physiological measures, and improvement in temporal processing is also evident. The results are explained within the internal clock model in terms of the pacemaker-accumulator functioning. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Ferro, cobre e zinco em adolescentes no estirão pubertário Iron, copper and zinc in adolescents during pubertal growth spurt

    Directory of Open Access Journals (Sweden)

    Marcia R.D. Urbano

    2002-01-01

    Full Text Available Objetivo: verificar o estado nutricional relativo ao ferro, cobre e zinco e a correlação entre índice de massa corporal, níveis séricos e dietéticos desses elementos, em adolescentes durante o estirão pubertário. Métodos: estudo descritivo, do tipo corte transversal, envolvendo uma amostra de 47 adolescentes atendidos em ambulatório de adolescência clínica, durante o período de março a dezembro de 1999, que se apresentavam no estirão pubertário, do total de 360 que freqüentaram o ambulatório no período, sendo 19 rapazes na faixa etária de 12,3 a 16 anos, e 28 moças na faixa etária de 11,1 a 13,6 anos. Variáveis analisadas: dietética (recordatório de 24 horas, freqüência e registro alimentar para determinar a ingestão de ferro, cobre e zinco; antropométrica (peso e altura para aferição do índice de massa corporal; bioquímica (dosagem sérica de ferro pelo kit in vitro Diagnóstica, ferritina pelo kit Immulite, cobre e zinco por espectrofotometria de absorção atômica. Utilizou-se o coeficiente de Spearman para análise estatistíca. Resultados: dos 47 adolescentes em estirão pubertário, apresentaram ingestão adequada de: ferro (95% e 36%, cobre (53% e 57% e zinco (21% e 21% nos sexos masculino e feminino, respectivamente. A maioria dos adolescentes era eutrófica segundo os percentis do IMC. Bioquimicamente, os rapazes apresentaram valores normais para ferro e zinco em toda a amostra; para cobre em 95% e para ferritina em 84%. As moças também apresentaram valores normais de ferro e zinco; para cobre em 96,4% e para ferritina em 96%. Não houve correlação estatisticamente significante entre IMC e concentração sérica de ferro, ferritina, cobre e zinco, e entre concentração sérica e ingestão dietética dos minerais estudados, nem tampouco para a relação ferro sérico e ferritina. Conclusões: não se sabe, até o momento, se os níveis séricos de zinco e cobre flutuam durante o crescimento, ou se

  13. Comparative proteomic profiling and possible toxicological mechanism of acute injury induced by carbon ion radiation in pubertal mice testes

    Science.gov (United States)

    Zhang, Hong

    2016-07-01

    We investigated potential mechanisms of acute injury in pubertal mice testes after exposure to carbon ion radiation (CIR). Serum testosterone was measured following whole-body irradiation with a 2Gy carbon ion beam. Comparative proteomic profiling and Western blotting were applied to identify potential biomarkers and measure protein expression, and terminal dUTP nick end-labeling (TUNEL) was performed to detect apoptotic cells. Immunohistochemistry and immunofluorescence were used to investigate protein localization. Serum testosterone was lowest at 24h after CIR, and 10 differentially expressed proteins were identified at this time point that included eIF4E, an important regulator of initiation that combines with mTOR and 4EBP1 to control protein synthesis via the mTOR signalling pathway during proliferation and apoptosis. Protein expression and localization studies confirmed their association with acute injury following exposure to CIR. These three proteins may be useful molecular markers for detecting abnormal spermatogenesis following exposure to environmental and cosmic radiation

  14. Perception regarding pubertal changes among rural adolescent boys of Haryana: A school based study

    Directory of Open Access Journals (Sweden)

    Vinod Chayal

    2016-06-01

    Full Text Available Background: Adolescence is a transition phase through which a child matures into an adult. The physical changes in the human body are from infant to child to adolescence to adult to old age.  All phases of life behave like a coin with both good and bad facets attached to each phase of life. Aims & Objectives:  1. To study perception and awareness regarding pubertal changes among school going adolescent boys. 2. To study the association between education and perceived pubertal problems among study subjects. Material & Methods: The study was conducted among male students of senior secondary schools of community development block Beri in one year. The study universe comprised of students in middle and late adolescence (aged 14-18 years studying in 9th to 12th classes of the senior secondary schools in the area. A total of 1000 male students were selected from these schools which were more than the required sample size of 891. Results: The study found that 42.66% students and a half (50% of students of class 9th & 10th and class 11th & 12th respectively considered that pubertal changes as a normal phenomenon. The majority of students admitted practicing masturbation and felt shy and guilty for practicing masturbation, also students felt fatigued after night emission. Conclusions: The study concludes that adolescent’s sexuality which often causes controversy and concern among adults is least discussed with them during adolescence. The reasons for this may be many, including moral grounds or because of concomitant health risks and threats to wellbeing.

  15. Reward sensitivity for a palatable food reward peaks during pubertal developmental in rats

    Directory of Open Access Journals (Sweden)

    Chris M Friemel

    2010-07-01

    Full Text Available Puberty is a critical period for the initiation of drug use and abuse. Because early drug use onset often accounts for a more severe progression of addiction, it is of importance to understand the underlying mechanisms and neurodevelopmental changes during puberty that are contributing to enhanced reward processing in teenagers. The present study investigated the progression of reward sensitivity towards a natural food reward over the whole course of adolescence in male rats (postnatal days 30–90 by monitoring consummatory, motivational behavior and neurobiological correlates of reward. Using a limited-free intake paradigm, consumption of sweetened condensed milk (SCM was measured repeatedly in adolescent and adult rats. Additionally, early- and mid-pubertal animals were tested in Progressive Ratio responding for SCM and c-fos protein expression in reward-associated brain structures was examined after odor-conditioning for SCM. We found a transient increase in SCM consumption and motivational incentive for SCM during puberty. This increased reward sensitivity was most pronounced around mid-puberty. The behavioral findings are paralleled by enhanced c-fos staining in reward-related structures revealing an intensified neuronal response after reward-cue presentation, distinctive for pubertal animals. Taken together, these data indicate an increase in reward sensitivity during adolescence accompanied by enhanced responsiveness of reward associated brain structures to incentive stimuli, and it seems that both is strongly pronounced around mid-puberty. Therefore, higher reward sensitivity during pubertal maturation might contribute to the enhanced vulnerability of teenagers for the initiation of experimental drug use.

  16. Genital Involvement In Pre-Pubertal Pediatric Population: A Rare Aspect of Crohn’s Disease

    Directory of Open Access Journals (Sweden)

    Qurratul Ann Warsi

    2016-09-01

    Full Text Available Crohn’s disease is an inflammatory bowel disease (IBD, characterized by chronic intestinal inflammation that causes the loss of immune tolerance leading to bizarre inflammatory signals and disruption of mucosal barriers. Environmental triggers and interaction of genetic determinants also play an indispensible role. In this case report, we present a pre-pubertal girl with intermittent and refractory genital swelling. We emphasize that Crohn’s disease must be considered in the differential diagnosis of recurrent, non-tender, erythematous and edematous lesions of the genital area. We conclude with future directions for diagnosing and managing vulvar Crohn’s disease in pediatric population.

  17. Ethanolic extract of Moringa oleifera Lam. leaves protect the pre-pubertal spermatogonial cells from cyclophosphamide-induced damage.

    Science.gov (United States)

    Nayak, Guruprasad; Honguntikar, Sachin D; Kalthur, Sneha Guruprasad; D'Souza, Antony Sylvan; Mutalik, Srinivas; Setty, Manjunath M; Kalyankumar, Raksha; Krishnamurthy, Hanumanthappa; Kalthur, Guruprasad; Adiga, Satish Kumar

    2016-04-22

    Moringa oleifera Lam. is widely cultivated in Asian and African countries for its medicinal and dietary significance. The leaves are highly nutritious and are known to possess various biological activities. Pre-pubertal Swiss albino male mice were injected with single dose of cyclophosphamide (CP, 200mg/kg body weight) or ethanolic extract of Moringa oleifera leaves (MOE, 100mg/kg body weight) intraperitoneally. In combination group, MOE was administered 24h prior to CP injection. CP induced a significant decrease in testicular weight (p<0.01) and depletion of germ cells (p<0.001) and higher level of DNA damage (p<0.001) compared to control. The expression of P53, Bax, Cytochrome C (Cyt C) was increased while there was a decrease in the expression of Bcl2, c-Kit and Oct4. Administration of MOE 24h prior to CP treatment ameliorated the depletion (p<0.001), DNA damage (p<0.001) and apoptosis (p<0.01) of germ cells induced by CP. The mitigating effect of MOE appears to be mediated by up-regulating the expression of c-Kit and Oct4 transcripts in P53-independent manner. MOE protects the spermatogonial cells from CP-induced damage by modulating the apoptotic response elicited by CP and therefore can be considered as an efficient method of male fertility preservation. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  18. Fatness rather than leptin sensitivity determines the timing of puberty in female mice.

    Science.gov (United States)

    Bohlen, Tabata M; Silveira, Marina A; Zampieri, Thais T; Frazão, Renata; Donato, Jose

    2016-03-05

    Leptin is a permissive factor for the onset of puberty. However, changes in adiposity frequently influence leptin sensitivity. Thus, the objective of the present study was to investigate how changes in body weight, fatness, leptin levels and leptin sensitivity interact to control the timing of puberty in female mice. Pre-pubertal obesity, induced by raising C57BL/6 mice in small litters, led to an early puberty onset. Inactivation of Socs3 gene in the brain or exclusively in leptin receptor-expressing cells reduced the body weight and leptin levels at pubertal onset, and increased leptin sensitivity. Notably, these female mice exhibited significant delays in vaginal opening, first estrus and onset of estrus cyclicity. In conclusion, our findings suggest that increased leptin sensitivity did not play an important role in favoring pubertal onset in female mice. Rather, changes in pubertal body weight, fatness and/or leptin levels were more important in influencing the timing of puberty.

  19. Pubertal Development and Peer Influence on Risky Decision Making

    Science.gov (United States)

    Kretsch, Natalie; Harden, Kathryn Paige

    2014-01-01

    Adolescents engage in more risky behavior when they are with peers and show, on average, heightened susceptibility to peer influence relative to children and adults. However, individual differences in susceptibility to peer influence are not well understood. The current study examined whether the effect of peers on adolescents' risky decision…

  20. Pubertal outcome in a female with virilizing adrenocortical carcinoma

    Science.gov (United States)

    Breidbart, Emily; Cameo, Tamara; Garvin, James H.; Hibshoosh, Hanina

    2016-01-01

    Adrenocortical tumors are neoplasms that rarely occur in pediatric patients. Adrenocortical carcinoma (ACC) is even more uncommon, and is an aggressive malignancy with 5-year survival of 55% in a registry series. There is a lack of information on long-term endocrine outcome in survivors. We describe a 10-year follow-up in a patient who presented at 3 years 5 months with a 1-year history of axillary odor and 6 months’ history of pubic hair development with an increased clitoral size. Androgen levels were increased and a pelvic sonogram revealed a suprarenal mass of the left kidney. The tumor was successfully removed. At 6 years 11 months, androgen levels increased again. Workup for tumor recurrence was negative and the findings likely represented early adrenarche. The patient had menarche at an appropriate time and attained a height appropriate for her family. PMID:26812773

  1. Focus takes time: structural effects on reading.

    Science.gov (United States)

    Lowder, Matthew W; Gordon, Peter C

    2015-12-01

    Previous eye-tracking work has yielded inconsistent evidence regarding whether readers spend more or less time encoding focused information compared with information that is not focused. We report the results of an eye-tracking experiment that used syntactic structure to manipulate whether a target word was linguistically defocused, neutral, or focused, while controlling for possible oculomotor differences across conditions. As the structure of the sentence made the target word increasingly more focused, reading times systematically increased. We propose that the longer reading times for linguistically focused words reflect deeper encoding, which explains previous findings showing that readers have better subsequent memory for focused versus defocused information.

  2. Serum inhibin B in healthy pubertal and adolescent boys

    DEFF Research Database (Denmark)

    Andersson, A M; Juul, A; Petersen, J H

    1997-01-01

    correlated strongly with age, and when the effect of age was taken into account, only the partial correlation between inhibin B and LH/testosterone remained statistically significant. At stage II of puberty, the positive partial correlation between inhibin B and LH/testosterone was still present. At stage...... III of puberty, an negative partial correlation between inhibin B and FSH, LH, and estradiol was present, whereas no correlation between inhibin B and testosterone could be observed from stage III onward. The negative correlation between inhibin B and FSH persisted from stage III of puberty onward...

  3. Early Universes with Effective Discrete Time

    CERN Document Server

    Baulieu, Laurent

    2016-01-01

    The mechanism for triggering the universe inflation could be that at very early periods the time variable was discrete instead of smooth. Alternatively, and perhaps equivalently, it could be the consequence that the metrics of the early universe was a strongly concentrated gravitational coherent state with very high frequency oscillations, allowing local pair creations by a generalisation to gravity of the Schwinger mechanism, perhaps by creation of black holes of masses superior to the Planck scale. The lattice spacing between two clicks in the discrete time picture corresponds to the inverse frequency of the gravitational coherent state in the other picture. In both cases, a much lower time than the Planck time might represent a new fundamental scale, giving new type of physics. To make possible a concrete estimation of the pair production probability, we propose that the oscillating coherent state metrics that defines this very early geometry minimises the Einstein gravity action coupled to interacting 1-,...

  4. Hypoxia: Exposure Time Until Significant Performance Effects

    Science.gov (United States)

    2016-03-07

    questionnaire which confirmed compliance with pre-established alcohol, caffeine , supplement, and medication usage standards given during consent and...the median reaction times and the third quartile reaction times evokes a relatively recent concept that is primarily associated with sleep ...face of increasing physiological demand, but cannot sustain it. For example, when the need for sleep is high, the level of attention will increase to

  5. NELF knockout is associated with impaired pubertal development and subfertility

    Science.gov (United States)

    Quaynor, Samuel D.; Ko, Eun Kyung; Chorich, Lynn P.; Sullivan, Megan E.; Demir, Durkadin; Waller, Jennifer L.; Kim, Hyung-Goo; Cameron, Richard S.; Layman, Lawrence C.

    2015-01-01

    Puberty and reproduction require proper signaling of the hypothalamic-pituitary-gonadal axis controlled by gonadotropin-releasing hormone (GnRH) neurons, which arise in the olfactory placode region and migrate along olfactory axons to the hypothalamus. Factors adversely affecting GnRH neuron specification, migration, and function lead to delayed puberty and infertility. Nasal embryonic luteinizing hormone-releasing factor (NELF) is a predominantly nuclear protein. NELF mutations have been demonstrated in patients with hypogonadotropic hypogonadism, but biallelic mutations are rare and heterozygous NELF mutations typically co-exist with mutations in another gene. Our previous studies in immortalized GnRH neurons supported a role for NELF in GnRH neuron migration. To better understand the physiology of NELF, a homozygous Nelf knockout (KO) mouse model was generated. Our findings indicate that female Nelf KO mice have delayed vaginal opening but no delay in time to first estrus, decreased uterine weight, and reduced GnRH neuron number. In contrast, male mice were normal at puberty. Both sexes of mice had impaired fertility manifested as reduced mean litter size. These data support that NELF has important reproductive functions. The milder than expected phenotype of KO mice also recapitulates the human phenotype since heterozygous NELF mutations usually require an additional mutation in a second gene to result in hypogonadotropic hypogonadism. PMID:25731822

  6. Responses of testis, epididymis, and sperm of pubertal rats exposed to functionalized multiwalled carbon nanotubes.

    Science.gov (United States)

    Farombi, Ebenezer O; Adedara, Isaac A; Forcados, Gilead E; Anao, Osemudiamen O; Agbowo, Agatha; Patlolla, Anita K

    2016-05-01

    The present study investigated the response of testes, epididymides and sperm in pubertal Wistar rats following exposure to 0, 0.25, 0.5, 0.75, and 1.0 mg kg(-1) functionalized multi-walled carbon nanotubes (f-MWCNTs) for 5 days. The results showed that administration of (f-MWCNTs) significantly increased the activities of superoxide dismutase, catalase, and glutathione peroxidase in a dose-dependent manner in both testes and sperm compared with control group. Moreover, the significant decrease in the activity of glutathione-S-transferase and glutathione level was accompanied with significant elevation in the levels of hydrogen peroxide and malondialdehyde in both testes and sperm of (f-MWCNTs)-treated rats. The spermiogram of (f-MWCNTs)-treated rats indicated significant decrease in epididymal sperm number, sperm progressive motility, testicular sperm number and daily sperm production with elevated sperm abnormalities when compared with the control. Exposure to (f-MWCNTs) decreased plasma testosterone level and produced marked morphological changes including decreased geminal epithelium, edema, congestion, reduced spermatogenic cells and focal areas of tubular degeneration in the testes. The lumen of the epididymides contained reduced sperm cells and there was mild to severe hyperplasia epithelial cells lining the duct of the epididymis. Collectively, pubertal exposure of male rats to (f-MWCNTs) elicited oxidative stress response resulting in marked testicular and epididymides dysfunction.

  7. Vegetable and Fruit Intakes Are Associated with hs-CRP Levels in Pre-Pubertal Girls.

    Science.gov (United States)

    Navarro, Pilar; de Dios, Olaya; Jois, Asha; Gavela-Pérez, Teresa; Gorgojo, Lydia; Martín-Moreno, José M; Soriano-Guillen, Leandro; Garcés, Carmen

    2017-03-02

    The influence of diet on inflammation in children remains unclear. We aimed to analyze the influence of diet on high-sensitivity C-reactive protein (hs-CRP) levels in a pre-pubertal population free of other influences that may affect hs-CRP levels. We determined hs-CRP levels in 571 six- to eight-year-old children using an hs-CRP ELISA kit. Information on food and nutrient intake was obtained through a food-frequency questionnaire. Overall dietary quality was assessed using the Healthy Eating Index (HEI). We found that girls in the highest tertile of hs-CRP levels had a higher intake of saturated fatty acid, and lower intakes of fiber and vitamin E and a lower HEI score when compared to those in tertiles 1 and 2. We also observed a significant decrease in fruit and vegetable intakes by hs-CRP tertile. Factor analysis showed that a dietary pattern that was loaded most strongly with vegetable, fruit, fiber and vitamin A and E intakes correlated negatively (-0.132, p hs-CRP. No such association was found in boys. In conclusion, our data show that girls with a poorer quality diet show higher hs-CRP levels already at a pre-pubertal age.

  8. Specificity of Metabolic Syndrome Model Reproduction at Pubertal and Adult Male Rats

    Directory of Open Access Journals (Sweden)

    Bondarenko Larysa Borysivna

    2015-09-01

    Full Text Available Background and Aims: Comparative estimation of metabolic syndrome (MS mediated changes of blood, cardio-vascular system, liver, pancreas and kidneys morphologic structure in adult and pubertal rats. Materials and Methods: Wistar albino male rats of two age categories (young animals of 21 days age (50-70g and adults (160-180g were divided into 4 groups (8 animals in each: 1 - Control 1 (intact young rats; 2 - Control 2 (intact adult rats; 3 - MS3 (young rats with MS and 4 - MS4 (adult rats with MS. The metabolic syndrome model was induced by full replacement of drinking water with 20% fructose solution (200g/l. After 60 days of MS modeling, determination of rat hematological and serum biochemical parameters, glucose tolerance, blood pressure, liver rates of lipid peroxydation and chromatin DNA fragmentation, as well as morphological macroscopic and microscopic studies were carried out. Results: In pubertal rats, glucose tolerance, hypertension, blood clotting disturbances, DNAfragmentation and lipid peroxydation rates were affected more profoundly, while mature rats showed greater Pseudo Pelger-Huet anomaly development, serum cholesterol and lipoproteins increases, liver and kidney morphology changes. Conclusions: Our current data combined with previous results of other authors allow us to conclude that an animal model (Wistar rats of MS is quite easily obtained in a full age range, from juvenile to mature rats.

  9. Toward a New Understanding of Early Menarche: The Role of Environmental Stress in Pubertal Timing.

    Science.gov (United States)

    Wierson, Michelle; And Others

    1993-01-01

    Examined divorce and interparental conflict in light of theory that environmental stress may trigger early menarche in adolescents. Findings from 71 adolescent females and their mothers revealed that, compared to girls from intact families, those from divorced families had earlier onset of menarche. Higher maternal reports of interparental…

  10. No Time Lag in the Photoelectric Effect

    Science.gov (United States)

    Gluck, Paul; Saering, Bernd

    2010-01-01

    The photoelectric effect was discovered in the 19th century by Heinrich Hertz. It is interesting to note that the same scientist showed experimentally the wave nature of light, and thereby vindicated Maxwell's wave theory, and discovered the effect in which light shows corpuscular behavior. This paper describes a simple demonstration, enabling one…

  11. No Time Lag in the Photoelectric Effect

    Science.gov (United States)

    Gluck, Paul; Saering, Bernd

    2010-01-01

    The photoelectric effect was discovered in the 19th century by Heinrich Hertz. It is interesting to note that the same scientist showed experimentally the wave nature of light, and thereby vindicated Maxwell's wave theory, and discovered the effect in which light shows corpuscular behavior. This paper describes a simple demonstration, enabling one…

  12. Effective dissipation: breaking time-reversal symmetry

    CERN Document Server

    Brown, Aidan I

    2016-01-01

    At molecular scales, fluctuations play a significant role and prevent biomolecular processes from always proceeding in a preferred direction, raising the question of how limited amounts of free energy can be dissipated to obtain directed progress. We examine the system and process characteristics that efficiently break time-reversal symmetry at fixed energy loss; in particular for a simple model of a molecular machine, an intermediate energy barrier produces unusually high asymmetry for a given dissipation. Such insight into symmetry-breaking factors that produce particularly high time asymmetry suggests generalizations to a broader class of systems.

  13. Short-term lower-body plyometric training improves whole body BMC, bone metabolic markers, and physical fitness in early pubertal male basketball players.

    Science.gov (United States)

    Zribi, Anis; Zouch, Mohamed; Chaari, Hamada; Bouajina, Elyes; Ben Nasr, Hela; Zaouali, Monia; Tabka, Zouhair

    2014-02-01

    The effects of a 9-week lower-body plyometric training program on bone mass, bone markers and physical fitness was examined in 51 early pubertal male basketball players divided randomly into a plyometric group (PG: 25 participants) and a control group (CG: 26 participants). Areal bone mineral density (aBMD), bone mineral content (BMC), and bone area (BA) in the whole body, L2-L4 vertebrae, and in total hip, serum levels of osteocalcin (Oc) and C-terminal telopeptide fragment of Type I collagen (CTx), jump, sprint and power abilities were assessed at baseline and 9 weeks. Group comparisons were done by independent student's t-test between means and analyses of (ANOVA) and covariance (ANCOVA), adjusting for baseline values. PG experienced a significant increase in Oc (p basketball players.

  14. Students' Pressure, Time Management and Effective Learning

    Science.gov (United States)

    Sun, Hechuan; Yang, Xiaolin

    2009-01-01

    Purpose: This paper aims to survey the status quo of the student pressure and the relationship between their daily time management and their learning outcomes in three different types of higher secondary schools at Shenyang, the capital city of Liaoning Province in mainland China. Design/methodology/approach: An investigation was carried out in 14…

  15. Effect of Mobile Use on Reaction Time

    Directory of Open Access Journals (Sweden)

    Chinmay Shah

    2010-04-01

    Full Text Available The use of cellular phones has skyrocketed in recent years, with more than 118 million subscribers in the United States as of July 1, 2001. Recent estimates suggest that cell phone users spend 60% of their cell phone time while driving. Reaction time is one of the important methods used to study a person's central information processing speed and fast coordinated peripheral movement response. The purpose of this study was to compare the reaction time without mobile use and with mobile use. It can be concluded that the reaction time is a prolonged with mobile use. The results of the study that has been described carry two significant implications for use of cellular phones. First, all users of cellular phones should be advised not to engage in intense phone conversations while the vehicle is moving. Businesses whose employees regularly carry on transactions by means of cellular phones might advise, or even direct that protracted dealings over the phone be avoided while the vehicle is underway.

  16. Quantum arrival time measurement and backflow effect

    CERN Document Server

    Muga, J G; Leavens, C R

    1999-01-01

    The current density for a freely evolving state without negative momentum components can temporarily be negative. The operational arrival time distribution, defined by the absorption rate of an ideal detector, is calculated for a model detector and compared with recently proposed distributions. Counterintuitive features of the backflow regime are discussed.

  17. Students' Pressure, Time Management and Effective Learning

    Science.gov (United States)

    Sun, Hechuan; Yang, Xiaolin

    2009-01-01

    Purpose: This paper aims to survey the status quo of the student pressure and the relationship between their daily time management and their learning outcomes in three different types of higher secondary schools at Shenyang, the capital city of Liaoning Province in mainland China. Design/methodology/approach: An investigation was carried out in 14…

  18. In vitro fertilization (IVF) from low or high antral follicle count pubertal beef heifers using semi-defined culture conditions

    Science.gov (United States)

    Antral follicle counts (AFC) vary among pubertal beef heifers. Our objective was to compare the in vitro maturation and fertilization of oocytes collected from low and high AFC heifers. Previously we reported results using serum-based IVF media and in this study report results using semi-defined m...

  19. Pre-menarche pubertal development following unique form of immigration: the case of girls adopted from China.

    Science.gov (United States)

    Tan, Tony Xing; Camras, Linda A

    2015-02-01

    Our study tested the hypothesis that drastic social-cultural change has an impact on girls' pre-menarche pubertal development. We focused on a unique group of Chinese immigrants who migrated out of China in infancy through international adoption. Our sample included 298 Chinese girls who were 7.3-11.1 years in 2011 (Mean = 8.8, SD = 0.9) and were adopted at 7-24 months (Mean = 12.6, SD = 3.4). We found that 34% showed at least one of four signs of pubertal development: Growth spurt, body fat increase, breast development, and body hair. Logistic regression analyses showed that the odds of growth spurt was raised by the girls' age in 2011, behavior problems in 2005, but lowered by the adoptive families' household income; the odds of body fat increase in 2011 was raised by the adopted Chinese girls' weight in 2007 and behavior problems in 2005, but was lowered by the adoptive mother's education level; the odds for breast development in 2011 was raised by the girls' age in 2011, weight in 2007, and behavior problems in 2009. For body hair, none of the factors predicted the odds. Prevalence of precocious puberty, based on the criterion of breast development before 8 years, was 3.5%. Overall, our study suggests that the pre-menarche pubertal development of adopted Chinese girls may be slightly advanced but also is affected by factors that affect non-adopted girls' pubertal development.

  20. Time variance effects and measurement error indications for MLS measurements

    DEFF Research Database (Denmark)

    Liu, Jiyuan

    1999-01-01

    Mathematical characteristics of Maximum-Length-Sequences are discussed, and effects of measuring on slightly time-varying systems with the MLS method are examined with computer simulations with MATLAB. A new coherence measure is suggested for the indication of time-variance effects. The results...... of the simulations show that the proposed MLS coherence can give an indication of time-variance effects....

  1. Sex-specific mouse liver gene expression: genome-wide analysis of developmental changes from pre-pubertal period to young adulthood

    Directory of Open Access Journals (Sweden)

    Conforto Tara L

    2012-04-01

    Full Text Available Abstract Background Early liver development and the transcriptional transitions during hepatogenesis are well characterized. However, gene expression changes during the late postnatal/pre-pubertal to young adulthood period are less well understood, especially with regards to sex-specific gene expression. Methods Microarray analysis of male and female mouse liver was carried out at 3, 4, and 8 wk of age to elucidate developmental changes in gene expression from the late postnatal/pre-pubertal period to young adulthood. Results A large number of sex-biased and sex-independent genes showed significant changes during this developmental period. Notably, sex-independent genes involved in cell cycle, chromosome condensation, and DNA replication were down regulated from 3 wk to 8 wk, while genes associated with metal ion binding, ion transport and kinase activity were up regulated. A majority of genes showing sex differential expression in adult liver did not display sex differences prior to puberty, at which time extensive changes in sex-specific gene expression were seen, primarily in males. Thus, in male liver, 76% of male-specific genes were up regulated and 47% of female-specific genes were down regulated from 3 to 8 wk of age, whereas in female liver 67% of sex-specific genes showed no significant change in expression. In both sexes, genes up regulated from 3 to 8 wk were significantly enriched (p p Ihh; female-specific Cdx4, Cux2, Tox, and Trim24 and may contribute to the developmental changes that lead to global acquisition of liver sex-specificity by 8 wk of age. Conclusions Overall, the observed changes in gene expression during postnatal liver development reflect the deceleration of liver growth and the induction of specialized liver functions, with widespread changes in sex-specific gene expression primarily occurring in male liver.

  2. Gonadal function is associated with cardiometabolic health in pre-pubertal boys with Klinefelter syndrome.

    Science.gov (United States)

    Davis, S; Lahlou, N; Bardsley, M; Temple, M-C; Kowal, K; Pyle, L; Zeitler, P; Ross, J

    2016-11-01

    The most common sex chromosome aneuploidy, Klinefelter syndrome (KS), is associated with primary gonadal failure and increased morbidity and mortality from cardiometabolic disorders in adulthood. Children with KS also have a high prevalence of metabolic syndrome (MetS) features. To assess the relationship of gonadal and cardiometabolic function in children with KS, we evaluated serum hormones [gonadotropins, inhibin B (INHB), anti-mullerian hormone (AMH), total testosterone (TT)], and features of MetS (waist circumference, fasting lipid panel, fasting blood glucose (FBG), and blood pressure) in 93 pre-pubertal boys with KS age 4-12 years (mean 7.7 ± 2.5 years). The cohort was grouped by age and tanner stage, and biomarkers were compared to normal ranges. A total of 80% of this pre-pubertal cohort had ≥1 feature of metabolic syndrome (MetS) and 11% had ≥3 features of MetS. Risk of MetS was independent of age and body mass index. Sertoli cell dysfunction was common with 18% having an INHB below the normal range. A low INHB was associated with higher FBG, triglycerides, LDL, and lower HDL (p < 0.05). An INHB <50 ng/dL yielded a sensitivity of 83% and a specificity of 79% for having ≥3 features of MetS. INHB and AMH positively correlated with each other (p < 0.001), and high AMH was protective of MetS. TT was below the lower limit of normal in 49% of subjects, with mean values significantly lower than expected (3.3 ng/dL vs. 4.9 ng/dL, p < 0.0001), however, no convincing relationship between TT and MetS was seen. In conclusion, gonadal and cardiometabolic dysfunction are prevalent in pre-pubertal boys with KS. Although the relationship of testosterone deficiency and MetS is well-known, this study is the first to report an association between impaired Sertoli cell function and cardiometabolic risk.

  3. Trends in puberty timing in humans and environmental modifiers

    DEFF Research Database (Denmark)

    Toppari, Jorma; Juul, Anders

    2010-01-01

    Secular trends in timing of puberty appear to continue although under-nutrition has not been any longer a limiting factor for pubertal development. Now obesity and other environmental reasons have been suspected to cause this trend, and endocrine disrupting chemicals have become into focus...... as possible contributors. Epidemiological studies on endocrine disrupters are still scarce and show only weak associations between exposures and timing of puberty. Since genetic background explains 50-80% of variability in the timing of puberty, it is not surprising that the observed environmental effects...... are rather modest when individual exposures are assessed. Despite that, some exposures have been reported to be associated to early (e.g., polybrominated biphenyls) or delayed (e.g., lead) puberty. Here we shortly review the available data on recent trends in timing of puberty and the possible role...

  4. Trends in puberty timing in humans and environmental modifiers

    DEFF Research Database (Denmark)

    Toppari, Jorma; Juul, Anders

    2010-01-01

    Secular trends in timing of puberty appear to continue although under-nutrition has not been any longer a limiting factor for pubertal development. Now obesity and other environmental reasons have been suspected to cause this trend, and endocrine disrupting chemicals have become into focus...... as possible contributors. Epidemiological studies on endocrine disrupters are still scarce and show only weak associations between exposures and timing of puberty. Since genetic background explains 50-80% of variability in the timing of puberty, it is not surprising that the observed environmental effects...... are rather modest when individual exposures are assessed. Despite that, some exposures have been reported to be associated to early (e.g., polybrominated biphenyls) or delayed (e.g., lead) puberty. Here we shortly review the available data on recent trends in timing of puberty and the possible role...

  5. Effect of fatigue on reaction time, response time, performance time, and kick impact in taekwondo roundhouse kick.

    Science.gov (United States)

    Sant'Ana, Jader; Franchini, Emerson; da Silva, Vinicius; Diefenthaeler, Fernando

    2017-06-01

    Reaction time and response time are considered important abilities and can potentially affect combat performance. This study investigated the effect of a specific fatigue protocol on reaction time, response time, performance time, and kick impact. Seven male athletes reported to the laboratory on two different days. During day one, athletes performed a specific progressive taekwondo test, and on day two, a protocol for determining reaction time, response time, performance time, and kick impact before and after a time to exhaustion test at an intensity level corresponding to the maximal kick frequency obtained during the specific progressive taekwondo test. Muscle activation from rectus femoris and kick impact of the preferred limb were assessed. No differences were observed for response time and performance time. However, kick impact decreased (43 ± 27 to 13 ± 10 g, p taekwondo training programmes on coordination-based exercises leading to improve response time and to reduce fatigue effects in order to improve technique effectiveness and enhance the possibilities of scoring in a competitive situation.

  6. Induction time effects in pulse combustors

    Energy Technology Data Exchange (ETDEWEB)

    Bell, J B; Marcus, D L; Pember, R B

    1999-04-09

    Combustion systems that take advantage of a periodic combustion process have many advantages over conventional systems. Their rate of heat transfer is greatly enhanced and their pollutant emissions are lower. They draw in their own supply of fuel and air and they are self-venting. They have few moving parts. The most common type of pulse combustor is based on a Helmholtz resonator - a burning cycle drives a resonant pressure wave, which in turn enhances the rate of combustion, resulting in a self-sustaining, large-scale oscillation. Although the basic physical mechanisms controlling such a process were explained by Rayleigh over a century ago, a full understanding of the operation of a pulse combustor still does not exist. The dominant processes in such a system--combustion, turbulent fluid dynamics, acoustics--are highly coupled and interact nonlinearly, which has reduced the design process to a costly and inefficient trial-and-error procedure. Several recent numerical and experimental studies, however, have been focused towards a better understanding of the basic underlying physics. Barr et al. [l] have elucidated the relative roles of the time scales governing the energy release, the turbulent mixing, and the acoustics. Keller et al. [5] have demonstrated the importance of the phase relation between the resonant pressure field in the tailpipe and the periodic energy release. Marcus et al. [6] have developed the capability for a fully three-dimensional simulation of the reacting flow in a pulse combustor. This paper is an application of that methodology to a detailed investigation of the frequency response of the model to changes in the chemical kinetics. The methodology consists of a fully conservative second-order Godunov algorithm for the inviscid, reacting gas dynamics equations coupled to an adaptive mesh refinement procedure[2]. The axisymmetric and three-dimensional simulations allow us to explore in detail the interaction between the transient fluid

  7. Age, sex, and pubertal phase influence mentalizing about emotions and actions in adolescents.

    Science.gov (United States)

    Keulers, Esther H H; Evers, Elisabeth A T; Stiers, Peter; Jolles, Jelle

    2010-01-01

    This study examined (1) emotional versus cognitive developmental trajectories and (2) the influence of age-extrinsic factors (i.e., sex and puberty). Using a cross-sectional design, adolescents (N = 252) divided into four age-groups (ages 13, 15, 17, 19) performed two versions of a mentalizing task, about emotions and actions, as well as the Tower task. First, performance on all tasks improved linearly into late adolescence (age 19). Thus no differential trajectories were found for emotional versus cognitive development. Second, girls outperformed boys in mentalizing speed regarding both emotions and actions. In boys, a later pubertal phase was associated with increased mentalizing speed after controlling for age-group.

  8. Biology of the Sertoli Cell in the Fetal, Pubertal, and Adult Mammalian Testis.

    Science.gov (United States)

    Chojnacka, Katarzyna; Zarzycka, Marta; Mruk, Dolores D

    A healthy man typically produces between 50 × 10(6) and 200 × 10(6) spermatozoa per day by spermatogenesis; in the absence of Sertoli cells in the male gonad, this individual would be infertile. In the adult testis, Sertoli cells are sustentacular cells that support germ cell development by secreting proteins and other important biomolecules that are essential for germ cell survival and maturation, establishing the blood-testis barrier, and facilitating spermatozoa detachment at spermiation. In the fetal testis, on the other hand, pre-Sertoli cells form the testis cords, the future seminiferous tubules. However, the role of pre-Sertoli cells in this process is much less clear than the function of Sertoli cells in the adult testis. Within this framework, we provide an overview of the biology of the fetal, pubertal, and adult Sertoli cell, highlighting relevant cell biology studies that have expanded our understanding of mammalian spermatogenesis.

  9. Mental health problems of Iranian female adolescents and its association with pubertal development: a nationwide study.

    Science.gov (United States)

    Rabbani, Ali; Mahmoudi-Gharaei, Javad; Mohammadi, Mohammad Reza; Motlagh, Mohammad Esmaeil; Mohammad, Kazem; Ardalan, Gelayol; Maftoon, Farzaneh; Shahryari, Safiyeh; Khodaei, Shahnaz; Sotoudeh, Aria; Ziaaldini, Hassan; Kamali, Kobra; Motaghian, Molouk

    2012-01-01

    Mental health problems including emotional and behavioral problems during puberty may be under influence of different risk factors including cultures, living in urban or rural areas and ethnic factors which may vary between different countries. The main aim of this study is to investigate the profile of emotional and behavioral problems and the role of factors such as age, stage of puberty, ethnicity, rurality and living in urban area, as risk factors in Iranian girls. As a part of a large national study we evaluated the emotional and behavioral problems in different stages of puberty in a community sample of Iranian adolescent girls from public schools that were selected by clustered random sampling method. In all subjects, demographic characteristics, and pubertal stages were measured. Emotional and behavioral problems were evaluated using Strength and Difficulties Questionnaire (SDQ). The associations of age, pubertal development indices, socioeconomic and demographic factors with the behavioral problems were assessed. A total number of 4576 students enrolled the study and responded to the questions. The mean age of participants was 13.83 ± 2.19 years. The mean total score of difficulties in participants was 14.34 ± 5.81. According to these results 813 (17.8%) adolescents had total problem scores higher than Goodman's cutoff points and the most frequent problem domain was conduct problems (20.5%). According to the results the most related variable with the total difficulty score of SDQ were ethnicity, residency in urban areas and development of menstrual cycle respectively. The results of this study showed that the most correlated factors with mental health problems in Iranian girls during puberty are ethnicity, urbanity and development of menstrual cycle.

  10. Mental Health Problems of Iranian Female Adolescents and Its Association with Pubertal Development: A Nationwide Study

    Directory of Open Access Journals (Sweden)

    Aria Sotoudeh

    2012-03-01

    Full Text Available Mental health problems including emotional and behavioral problems during puberty may be under influence of different risk factors including cultures, living in urban or rural areas and ethnic factors which may vary between different countries. The main aim of this study is to investigate the profile of emotional and behavioral problems and the role of factors such as age, stage of puberty, ethnicity, rurality and living in urban area, as risk factors in Iranian girls. As a part of a large national study we evaluated the emotional and behavioral problems in different stages of puberty in a community sample of Iranian adolescent girls from public schools that were selected by clustered random sampling method. In all subjects, demographic characteristics, and pubertal stages were measured. Emotional and behavioral problems were evaluated using Strength and Difficulties Questionnaire (SDQ. The associations of age, pubertal development indices, socioeconomic and demographic factors with the behavioral problems were assessed. A total number of 4576 students enrolled the study and responded to the questions. The mean age of participants was 13.83 2.19 years. The mean total score of difficulties in participants was 14.34 5.81. According to these results 813 (17.8% adolescents had total problem scores higher than Goodmans cutoff points and the most frequent problem domain was conduct problems (20.5%. According to the results the most related variable with the total difficulty score of SDQ were ethnicity, residency in urban areas and development of menstrual cycle respectively. The results of this study showed that the most correlated factors with mental health problems in Iranian girls during puberty are ethnicity, urbanity and development of menstrual cycle.

  11. Passive microrheology in the effective time domain: analyzing time dependent colloidal dispersions.

    Science.gov (United States)

    Vyas, Bhavna M; Orpe, Ashish V; Kaushal, Manish; Joshi, Yogesh M

    2016-10-21

    We studied the aging dynamics of an aqueous suspension of LAPONITE®, a model time dependent soft glassy material, using a passive microrheology technique. This system is known to undergo physical aging during which its microstructure evolves progressively to explore lower free energy states. Optical microscopy is used to monitor the motion of micron-sized tracer probes embedded in a sample kept between two glass plates. The mean square displacements (MSD) obtained from the motion of the tracer particles show a systematic change from a purely diffusive behavior at short aging times to a subdiffusive behavior as the material ages. Interestingly, the MSDs at all the aging times as well as different LAPONITE® concentrations superpose remarkably to show a time-aging time master curve when the system is transformed from the real time domain to the effective time domain, which is obtained by rescaling the material clock to account for the age dependent relaxation time. The transformation of the master curve from the effective time domain to the real time domain leads to the prediction of the MSD in real time over a span of 5 decades when the measured data at individual aging times are only over 2 decades. Since the MSD obtained from microrheology is proportional to the creep compliance of a material, by using the Boltzmann superposition principle along with the convolution relation in the effective time domain, we predict the stress relaxation behavior of the system in real time. This work shows that the effective time approach applied to microrheology facilitates the prediction of long time creep and relaxation dynamics of a time dependent soft material by carrying out short time experiments at different aging times.

  12. Effect of Exercise Intensity Level on Choice Reaction Time1

    National Research Council Canada - National Science Library

    Jin, Xi; Eason, Bobby; Loftin, Mark

    2015-01-01

    The primary aim of this study was to examine the effects of exercise intensity and duration on choice reaction time with a secondary aim to examine the influence of aerobic fitness on choice reaction time...

  13. Essential time management how to become more productive and effective

    CERN Document Server

    Hilder, Brett

    2011-01-01

    Time is a resource like any other. Using your time effectively can transform your personal productivity and determine your level of success. Moreover, it can change your level of job satisfaction and confidence.

  14. Pubertal Stage, Body Mass Index, and Cardiometabolic Risk in Children and Adolescents in Bogotá, Colombia: The Cross-Sectional Fuprecol Study

    Directory of Open Access Journals (Sweden)

    Robinson Ramírez-Vélez

    2017-06-01

    Full Text Available This study explored the association between pubertal stage and anthropometric and cardiometabolic risk factors in youth. A cross-sectional study was conducted in 2877 Colombian children and adolescents (9–17.9 years of age. Weight, height, and waist circumference were measured and body mass index (BMI was calculated. A biochemical study was performed to determine the cardiometabolic risk index (CMRI. Blood pressure was evaluated and pubertal stage was assessed with the Tanner criteria. Hierarchical multiple regression analyses were performed. The most significant variable (p < 0.05 in the prognosis of cardiometabolic risk was found to be the BMI in both boys and girls. In the case of girls, the pubertal stage was also a CMRI predictive factor. In conclusion, BMI was an important indicator of cardiovascular risk in both sexes. Pubertal stage was associated with cardiovascular risk only in the girls.

  15. Valve timing: its effect on emissions and fuel economy

    Energy Technology Data Exchange (ETDEWEB)

    Bechtold, R.L.; Marshall, W.F.

    1977-08-01

    The effects of valve timing on exhaust emissions and fuel consumption were investigated experimentally. Emission control through the use of varied valve timing compared to conventional emissions control hardware was documented along with the effects of valve timing on emissions. Fuel consumption trends with changed valve timing were determined. The engine design of the test vehicle allowed independent adjustment of intake and exhaust valve timing. Emissions and fuel consumption were determined for steady-state speeds of 20 through 60 mph in 10 mph increments. A wide variety of intake and exhaust valve timing combinations were tested and the results compared to those of the production vehicle before modification. These results showed that valve timing has a significant effect on oxides of nitrogen emissions, but additional emissions control hardware is necessary to meet current and proposed emission regulations. Compared to emission control, varied valve timing holds more promise for reduced fuel consumption through a gain in cycle efficiency at various speeds.

  16. Metabolic Syndrome in Children and Adolescents: a Critical Approach Considering the Interaction between Pubertal Stage and Insulin Resistance.

    Science.gov (United States)

    Reinehr, Thomas

    2016-01-01

    Pediatricians increasingly diagnose the metabolic syndrome (MetS) in recent years to describe cardiovascular risk and to guide management of the obese child. However, there is an ongoing discussion about how to define the MetS in childhood and adolescence. Since insulin resistance-the major driver of MetS-is influenced by pubertal stage, it is questionable to use definitions for MetS in children and adolescents that do not take into account pubertal status. A metabolic healthy status in prepubertal stage does not predict a metabolic healthy status during puberty. Furthermore, cardiovascular risk factors improve at the end of puberty without treatment. However, having a uniform internationally accepted definition of the MetS for children and adolescents would be very helpful for the description of populations in different studies. Therefore, the concept of MetS has to be revisited under the influence of puberty stage.

  17. Method for effective dead time measurement in counting systems

    Energy Technology Data Exchange (ETDEWEB)

    Vinagre, F.L.R. E-mail: fleonor@saturno.fis.uc.pt; Conde, C.A.N

    2001-04-21

    The counting losses introduced by the dead time of a counting system are a limiting factor in counting measurements. The purpose of this work is to report an efficient method for the measurement of the effective dead time of a counting system and to characterize its dead time behavior, providing a way to investigate each experimental situation. The method, which we designate as Delayed and Mixed Pulses method, is based on the artificial piling-up of detector pulses with electronic pulses delayed by a specific time interval. It is applicable to the measurement of the effective dead time of a counting system, including both pile-up effects and the dead time characteristics of the elements of the counting chain. With counting systems relying on gaseous radiation detectors, we achieved a standard uncertainty of about 5-10% in the dead times measured.

  18. Acute effects of static and dynamic stretching on balance, agility, reaction time and movement time.

    Science.gov (United States)

    Chatzopoulos, Dimitris; Galazoulas, Christos; Patikas, Dimitrios; Kotzamanidis, Christos

    2014-05-01

    The purpose of this study was to compare the acute effects of three different stretching protocols on balance, agility, reaction time and movement time of the upper limbs. Participants were thirty one female high school athletes (age = 17.3 ± 0.5 yr.). All participants performed one of the following protocols on different days: (a) 3 min jogging followed by 7 min static stretching (SS), (b) 3 min jogging followed by 7 min dynamic stretching (DS), and (c) 3 min jogging followed by 7 min of rest (NS). After the protocols participants performed the following tests: dynamic balance, 505 agility test, reaction time (time between a sound stimulus and release of a button) and movement time (movement of the upper extremity over a 0.5 m distance). The order of stretching protocols and performance tests were counterbalanced to avoid carryover effects. Repeated measures analysis of variance revealed significant main effects for all variables except reaction time. The DS protocol compared to SS performed significantly better in balance, agility and movement time. Additionally, the DS protocol compared to NS performed significantly better in agility. According to the results of the study, a DS protocol is more appropriate than SS for activities that require balance, rapid change of running direction (agility) and movement time of the upper extremities. Key pointsStatic stretching has a negative effect on balance and agility performance compared to dynamic stretching.There was no effect of the stretching protocols on reaction time.Dynamic stretching was more effective than static stretching for increasing movement time of the upper extremities.

  19. Uncertainties of Euclidean Time Extrapolation in Lattice Effective Field Theory

    CERN Document Server

    Lähde, Timo A; Krebs, Hermann; Lee, Dean; Meißner, Ulf-G; Rupak, Gautam

    2014-01-01

    Extrapolations in Euclidean time form a central part of Nuclear Lattice Effective Field Theory (NLEFT) calculations using the Projection Monte Carlo method, as the sign problem in many cases prevents simulations at large Euclidean time. We review the next-to-next-to-leading order NLEFT results for the alpha nuclei up to $^{28}$Si, with emphasis on the Euclidean time extrapolations, their expected accuracy and potential pitfalls. We also discuss possible avenues for improving the reliability of Euclidean time extrapolations in NLEFT.

  20. Pubertal Stress and Nutrition and their Association with Sexual Orientation and Height in the Add Health Data.

    Science.gov (United States)

    Skorska, Malvina N; Bogaert, Anthony F

    2017-01-01

    A number of studies have indicated that gay men tend to be shorter, on average, than heterosexual men. Less evidence exists that lesbian women are taller, on average, than heterosexual women. The most popular explanation of the association between sexual orientation and height involves prenatal factors, such that, for example, gay men may have been exposed to lower than typical androgens during fetal development, which impacts their height and sexual orientation as adults. An alternative explanation involves stress, given that stress has been associated with sexual minority identification and with lower height. Another alternative explanation involves nutrition, although its relationship is less clear with sexual minority identification. Using the Add Health data, which is a large, nationally representative and longitudinal sample of American adolescents (n = 14,786), we tested a mediation model, such that sexual orientation → pubertal stress/nutrition → height. Within men, we found that gay men (n = 126) were shorter, on average, than heterosexual men (n = 6412). None of the 24 pubertal stress-related and 15 pubertal nutrition-related variables assessed in the Add Health data mediated the relationship between sexual orientation and height in men. Within women, lesbians (n = 75) did not differ significantly in stature compared to heterosexual women (n = 6267). Thus, prenatal mechanisms (e.g., hormones, maternal immune response) are likely better candidates for explaining the height difference between gay men and heterosexual men.

  1. The Effectiveness of Time Management Strategies Instruction on Students' Academic Time Management and Academic Self Efficacy

    Science.gov (United States)

    Kader, Fathi Abdul Hamid Abdul; Eissa, Mourad Ali

    2015-01-01

    This study investigated the effect of using time management strategies instruction on improving first year learning disabled students' academic time management and academic self efficacy. A total of 60 students identified with LD participated. The sample was divided into two groups; experimental (n = 30 boys) and control (n = 30 boys). ANCOVA and…

  2. Principal Time Management Skills: Explaining Patterns in Principals' Time Use, Job Stress, and Perceived Effectiveness

    Science.gov (United States)

    Grissom, Jason A.; Loeb, Susanna; Mitani, Hajime

    2015-01-01

    Purpose: Time demands faced by school principals make principals' work increasingly difficult. Research outside education suggests that effective time management skills may help principals meet job demands, reduce job stress, and improve their performance. The purpose of this paper is to investigate these hypotheses. Design/methodology/approach:…

  3. Principal Time Management Skills: Explaining Patterns in Principals' Time Use, Job Stress, and Perceived Effectiveness

    Science.gov (United States)

    Grissom, Jason A.; Loeb, Susanna; Mitani, Hajime

    2015-01-01

    Purpose: Time demands faced by school principals make principals' work increasingly difficult. Research outside education suggests that effective time management skills may help principals meet job demands, reduce job stress, and improve their performance. The purpose of this paper is to investigate these hypotheses. Design/methodology/approach:…

  4. Longitudinal study of the pattern of pubertal development in Cantonese schoolgirls%广州女孩青春期发育模式的纵向研究

    Institute of Scientific and Technical Information of China (English)

    李燕虹; 马华梅; 陈红珊; 苏喆; 古玉芬; 杜敏联

    2009-01-01

    development (PH2) was 10.67 (9.92-11.38) years. Menarche occurred at (12.35±1.30) years. The age at reaching B2, age at reaching PH2 and age of menarchc were all later than that observed in the cross-section study performed in 2003, Guangzhou, China. Peak height velocity (PHV) was reached at (10.52±1.07) years, 1.00 (0.50-1.50) years after B2 was reached. Interval between " age at onset of breast development" and "age at menarehe" was 2.92 (2.08-3.67 ) years. Duration of pubertal growth ( defined as the time from age at B2 to age at which adult height was attained ) was (4.80±0.85) years. (2) Average final adult bethgt (FAH) was (158.74±5.74) cm. As compared with the cross-section studies held in Guangzhou, China, the FAH in our study was higher than that observed in 1985 but was lower than that observed in 2003. (3) Multiple linear regression analyses showed that the age reaching B2 was an independent factor associated with the age of menarche. (4) Durations of breast stages, interval between B2 and menarcbe and duration of pubertal growth were similar to that reported in the longitudinal studies in the United Kingdom (1969), Senegal (1995-2000), the United States (1986-1996). Conclnsion In healthy Cantonese schoolgirls, the timing of sexual maturation was in a trend of decline in the past 20 years, however, it may have no significant impacts on the tempo of pubertal development and FAH.

  5. Angular dependence of Wigner time delay: Relativistic Effects

    Science.gov (United States)

    Mandal, A.; Deshmukh, P. C.; Manson, S. T.; Kkeifets, A. S.

    2016-05-01

    Laser assisted photoionization time delay mainly consists of two parts: Wigner time delay, and time delay in continuum-continuum transition. Wigner time delay results from the energy derivative of the phase of the photoionization amplitude (matrix element). In general, the photoionization time delay is not the same in all directions relative to the incident photon polarization, although when a single transition dominates the amplitude, the resultant time delay is essentially isotropic. The relativistic-random-phase approximation is employed to determine the Wigner time delay in photoionization from the outer np subshells of the noble gas atoms, Ne through Xe. The time delay is found to significantly depend on angle, as well as energy. The angular dependence of the time delay is found to be quite sensitive to atomic dynamics and relativistic effects, and exhibit strong energy and angular variation in the neighborhood of Cooper minima. Work supported by DOE, Office of Chemical Sciences and DST (India).

  6. Association of adiposity genetic variants with menarche timing in 92,105 women of European descent.

    Science.gov (United States)

    Fernández-Rhodes, Lindsay; Demerath, Ellen W; Cousminer, Diana L; Tao, Ran; Dreyfus, Jill G; Esko, Tõnu; Smith, Albert V; Gudnason, Vilmundur; Harris, Tamara B; Launer, Lenore; McArdle, Patrick F; Yerges-Armstrong, Laura M; Elks, Cathy E; Strachan, David P; Kutalik, Zoltán; Vollenweider, Peter; Feenstra, Bjarke; Boyd, Heather A; Metspalu, Andres; Mihailov, Evelin; Broer, Linda; Zillikens, M Carola; Oostra, Ben; van Duijn, Cornelia M; Lunetta, Kathryn L; Perry, John R B; Murray, Anna; Koller, Daniel L; Lai, Dongbing; Corre, Tanguy; Toniolo, Daniela; Albrecht, Eva; Stöckl, Doris; Grallert, Harald; Gieger, Christian; Hayward, Caroline; Polasek, Ozren; Rudan, Igor; Wilson, James F; He, Chunyan; Kraft, Peter; Hu, Frank B; Hunter, David J; Hottenga, Jouke-Jan; Willemsen, Gonneke; Boomsma, Dorret I; Byrne, Enda M; Martin, Nicholas G; Montgomery, Grant W; Warrington, Nicole M; Pennell, Craig E; Stolk, Lisette; Visser, Jenny A; Hofman, Albert; Uitterlinden, André G; Rivadeneira, Fernando; Lin, Peng; Fisher, Sherri L; Bierut, Laura J; Crisponi, Laura; Porcu, Eleonora; Mangino, Massimo; Zhai, Guangju; Spector, Tim D; Buring, Julie E; Rose, Lynda M; Ridker, Paul M; Poole, Charles; Hirschhorn, Joel N; Murabito, Joanne M; Chasman, Daniel I; Widen, Elisabeth; North, Kari E; Ong, Ken K; Franceschini, Nora

    2013-08-01

    Obesity is of global health concern. There are well-described inverse relationships between female pubertal timing and obesity. Recent genome-wide association studies of age at menarche identified several obesity-related variants. Using data from the ReproGen Consortium, we employed meta-analytical techniques to estimate the associations of 95 a priori and recently identified obesity-related (body mass index (weight (kg)/height (m)(2)), waist circumference, and waist:hip ratio) single-nucleotide polymorphisms (SNPs) with age at menarche in 92,116 women of European descent from 38 studies (1970-2010), in order to estimate associations between genetic variants associated with central or overall adiposity and pubertal timing in girls. Investigators in each study performed a separate analysis of associations between the selected SNPs and age at menarche (ages 9-17 years) using linear regression models and adjusting for birth year, site (as appropriate), and population stratification. Heterogeneity of effect-measure estimates was investigated using meta-regression. Six novel associations of body mass index loci with age at menarche were identified, and 11 adiposity loci previously reported to be associated with age at menarche were confirmed, but none of the central adiposity variants individually showed significant associations. These findings suggest complex genetic relationships between menarche and overall obesity, and to a lesser extent central obesity, in normal processes of growth and development.

  7. Dead time effects in laser Doppler anemometry measurements

    DEFF Research Database (Denmark)

    Velte, Clara Marika; Buchhave, Preben; George, William K.

    2014-01-01

    We present velocity power spectra computed by the so-called direct method from burst-type laser Doppler anemometer (LDA) data, both measured in a turbulent round jet and generated in a computer. Using today’s powerful computers, we have been able to study more properties of the computed spectra...... frequency range, starting around the cutoff frequency due to the finite size of the MV. Using computer-generated data mimicking the LDA data, these effects have previously been shown to appear due to the effect of dead time, i.e., the finite time during which the system is not able to acquire new...... measurements. These dead times can be traced back to the fact that the burst-mode LDA cannot measure more than one signal burst at a time. Since the dead time is approximately equal to the residence time for a particle traversing a measurement volume, we are dealing with widely varying dead times, which...

  8. Acute Effects of Static and Dynamic Stretching on Balance, Agility, Reaction Time and Movement Time

    Directory of Open Access Journals (Sweden)

    Dimitris Chatzopoulos

    2014-06-01

    Full Text Available The purpose of this study was to compare the acute effects of three different stretching protocols on balance, agility, reaction time and movement time of the upper limbs. Participants were thirty one female high school athletes (age = 17.3 ± 0.5 yr.. All participants performed one of the following protocols on different days: (a 3 min jogging followed by 7 min static stretching (SS, (b 3 min jogging followed by 7 min dynamic stretching (DS, and (c 3 min jogging followed by 7 min of rest (NS. After the protocols participants performed the following tests: dynamic balance, 505 agility test, reaction time (time between a sound stimulus and release of a button and movement time (movement of the upper extremity over a 0.5 m distance. The order of stretching protocols and performance tests were counterbalanced to avoid carryover effects. Repeated measures analysis of variance revealed significant main effects for all variables except reaction time. The DS protocol compared to SS performed significantly better in balance, agility and movement time. Additionally, the DS protocol compared to NS performed significantly better in agility. According to the results of the study, a DS protocol is more appropriate than SS for activities that require balance, rapid change of running direction (agility and movement time of the upper extremities.

  9. Effects of daylight savings time changes on stock market volatility.

    Science.gov (United States)

    Berument, M Hakan; Dogan, Nukhet; Onar, Bahar

    2010-04-01

    The presence of daylight savings time effects on stock returns and on stock volatility was investigated using an EGARCH specification to model the conditional variance. The evidence gathered from the major United States stock markets for the period between 1967 and 2007 did not support the existence of the daylight savings time effect on stock returns or on volatility. Returns on the first business day following daylight savings time changes were not lower nor was the volatility higher, as would be expected if there were an effect.

  10. Delay time and Hartman effect in strain engineered graphene

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xi, E-mail: xchen@shu.edu.cn; Deng, Zhi-Yong [Department of Physics, Shanghai University, 200444 Shanghai (China); Ban, Yue, E-mail: yban@shu.edu.cn [Department of Electronic Information Materials, Shanghai University, 200444 Shanghai (China)

    2014-05-07

    Tunneling times, including group delay and dwell time, are studied for massless Dirac electrons transmitting through a one-dimensional barrier in strain-engineered graphene. The Hartman effect, the independence of group delay on barrier length, is induced by the strain effect, and associated with the transmission gap and the evanescent mode. The influence of barrier height/length and strain modulus/direction on the group delay is also discussed, which provides the flexibility to control the group delay with applications in graphene-based devices. The relationship between group delay and dwell time is finally derived to clarify the nature of the Hartman effect.

  11. The Effect of Police Response Time on Crime Detection

    DEFF Research Database (Denmark)

    Blanes i Vidal, Jordi; Kirchmaier, Tom

    Police agencies devote vast resources to minimising the time that it takes them to attend the scene of a crime. Despite this, the long-standing consensus is that police response time has no meaningful effect on the likelihood of catching offenders. We revisit this question using a uniquely rich...... preferred estimate, a 10% increase in response time leads to a 4.6 percentage points decrease in the likelihood of detection. A faster response time also decreases the number of days that it takes for the police to detect a crime, conditional on eventual detection. We find stronger effects for thefts than...... for violent offenses, although the effects are large for every type of crime. We identify the higher likelihood that a suspect will be named by a victim or witness as an important mechanism though which response time makes a difference....

  12. The effect of masking in the attentional dwell time paradigm

    DEFF Research Database (Denmark)

    Petersen, Anders

    2009-01-01

    A temporary functional blindness to the second of two spatially separated targets has been identified in numerous studies of temporal visual attention. This effect is known as attentional dwell time and is maximal 200 to 500 ms after presentation of the first target (e.g. Duncan, Ward, Shapiro......, 1994). In most studies of attentional dwell time, two masked targets have been used. Moore et al. (1996) have criticised the masking of the first target when measuring the attentional dwell time, finding a shorter attentional dwell time when the first mask was omitted. In the presented work, the effect...... an impairment of the second target. Hence, the attentional dwell time may be a combined effect arising from attending to both the first target and its mask....

  13. Physical provocation of pubertal anabolic androgenic steroid exposed male rats elicits aggression towards females.

    Science.gov (United States)

    Cunningham, Rebecca L; McGinnis, Marilyn Y

    2006-09-01

    Human studies suggest that anabolic androgenic steroid (AAS) users are aggressive towards women. This study used a rat model to evaluate whether AAS potentiated aggression towards females and the conditions under which this occurs. Gonadally intact pubertal male rats received one of the following AAS treatments (5 mg/kg s.c. 5 days/week for nine weeks): testosterone (T), stanozolol (S), testosterone + stanozolol (T + S), or vehicle control. Each rat was tested with 3 conspecific stimuli: ovariectomized females (OVX), estrogen only females (E), and estrogen + progesterone females (E + P). The response to physical provocation was tested under three conditions: without physical provocation, provocation of the experimental male, and provocation of the conspecific female. Provocation was a mild tail pinch. Both aggressive and sexual behaviors were measured during each test. In the absence of physical provocation, AAS males were not aggressive towards females. However, provocation significantly increased aggression in males treated with testosterone but only towards OVX females. In the presence of E or E + P females, all animals displayed sex behavior, not aggression. Thus, factors such as the nature of the AAS and the hormonal status of the females are important in determining whether male rats will be aggressive towards females. However, the most salient factor determining aggression towards females is the presence of provocation in combination with high levels of testosterone.

  14. Genetic factors modulate the impact of pubertal androgen excess on insulin sensitivity and fertility.

    Directory of Open Access Journals (Sweden)

    Abigail R Dowling

    Full Text Available Polycystic ovary syndrome (PCOS is the most common endocrine disorder of reproductive age women. The syndrome is caused by a combination of environmental influences and genetic predisposition. Despite extensive efforts, the heritable factors contributing to PCOS development are not fully understood. The objective of this study was to test the hypothesis that genetic background contributes to the development of a PCOS-like reproductive and metabolic phenotype in mice exposed to excess DHEA during the pubertal transition. We tested whether the PCOS phenotype would be more pronounced on the diabetes-prone C57BL/6 background than the previously used strain, BALB/cByJ. In addition, we examined strain-dependent upregulation of the expression of ovarian and extra-ovarian candidate genes implicated in human PCOS, genes containing known strain variants, and genes involved with steroidogenesis or insulin sensitivity. These studies show that there are significant strain-related differences in metabolic response to excess androgen exposure during puberty. Additionally, our results suggest the C57BL/6J strain provides a more robust and uniform experimental platform for PCOS research than the BALB/cByJ strain.

  15. Association between Physical Activity and Cardiovascular Risk in Chinese Youth Independent of Age and Pubertal Stage

    Directory of Open Access Journals (Sweden)

    Lau Joseph TF

    2010-06-01

    Full Text Available Abstract Background Childhood and adolescence are critical periods of habit formation with substantial tracking of lifestyle and cardiovascular risk into adulthood. There are various guidelines on recommended levels of physical activity in youth of school-age. Despite the epidemic of obesity and diabetes in China, there is a paucity of data in this regard in Chinese youth. We examined the association of self-reported level of physical activity and cardiovascular risk in Hong Kong Chinese youth of school-age. Methods This was a cross-sectional study conducted in 2007-8 in a school setting with 2119 Hong Kong Chinese youth aged 6-20 years. Physical activity level was assessed using a validated questionnaire, CUHK-PARCY (The Chinese University of Hong Kong: Physical Activity Rating for Children and Youth. A summary risk score comprising of waist circumference, blood pressure, fasting plasma glucose and lipids was constructed to quantify cardiovascular risk. Results In this cohort, 21.5% reported high level of physical activity with boys being more active than girls (32.1% versus 14.1%, p Conclusion Self-reported level of physical activity is associated with cardiovascular risk factors in Chinese youth after adjusting for sex and pubertal stage.

  16. Evaluation of GnRH analogue testing in diagnosis and management of children with pubertal disorders

    Directory of Open Access Journals (Sweden)

    Hemchand K Prasad

    2012-01-01

    Full Text Available Context: Gonadotrophin releasing hormone (GnRH stimulation test is pivotal in the assessment of children with pubertal disorders. However, lack of availability and high cost often result in the test falling into disfavor. We routinely use the GnRH analogue stimulation test as an alternative at our center. Aim: To present the data on children with endocrine disorders who underwent GnRH agonist stimulation test in pediatric endocrine clinic of a tertiary care referral hospital. Setting and Design: Pediatric endocrine clinic of a tertiary care referral hospital. Retrospective analysis of case records. Materials and Methods: The details pertaining to clinical and radiological parameters and hormonal tests were retrieved from case records of 15 children who underwent GnRH agonist stimulation test from May 2010 to April 2011. Results: Indications for testing with GnRH analogue were evaluation of delayed puberty, diagnosis of precocious puberty, assessment of hormonal suppression in treatment of precocious puberty and micropenis in two, nine, three and one cases, respectively. The results of the test and clinical and radiological parameters were in concordance. The test was also crucial in diagnosing the onset of central precocious puberty in two children with congenital adrenal hyperplasia. Conclusion: GnRH agonist test is a convenient, safe test that can be performed on an out-patient basis and can help the clinicians in the correct diagnosis and appropriate treatment of various puberty-related disorders.

  17. Evolution of fat oxidation during exercise in obese pubertal boys: clinical implications.

    Science.gov (United States)

    Zunquin, Gautier; Theunynck, Denis; Sesboue, Bruno; Arhan, Pierre; Bougle, Dominique

    2009-02-15

    In this study, we examined fat oxidation rates during exercise in obese pubescent boys. Three groups of pubescent boys (16 pre-pubescent, Tanner's stage I; 16 pubescent, Tanner's stage III; and 14 post-pubescent, Tanner's stage V) performed a graded test on a leg cycle ergometer. The first step of the test was fixed at 30 W and power was gradually increased by 20 W every 3.5 min. Oxygen consumption (VO(2)) and carbon dioxide production (VCO(2)) were determined as the means of measurements during the last 30 s of each step, which allowed us to calculate fat oxidation rates versus exercise intensity. Between 20 and 50% of peak oxygen consumption (VO(2peak)), fat oxidation rate in relative values (mg . min(-1) . kg FFM(-1)) decreased continuously with pubertal development. In the same way, the maximum rate of fat oxidation occurred at a lower percentage of VO(2peak) (pre-pubescent: 49.47 +/- 1.62%; pubescent: 47.43 +/- 1.26%; post-pubescent: 45.00 +/- 0.97%). Our results confirm that puberty is responsible for a decrease in fat free mass capacities to use fat during exercise. The results suggest that post-pubescent obese boys need to practise physical activity at a lower intensity than pre-pubescent boys to enhance lipolysis and diminish adipose tissue and the consequences of obesity.

  18. The Effects of Breaking up Prolonged Sitting Time

    DEFF Research Database (Denmark)

    Benatti, Fabiana Braga; Ried-Larsen, Mathias

    2015-01-01

    on the electronic databases PUBMED and SCOPUS was independently conducted by two researchers. Only prospective intervention studies (controlled and uncontrolled) evaluating the effects of explicitly replacing sitting time with physical activity (including standing) on metabolic parameters as outcomes were included...

  19. Effect of enamel etching time on roughness and bond strength

    National Research Council Canada - National Science Library

    Barkmeier, Wayne W; Erickson, Robert L; Kimmes, Nicole S; Latta, Mark A; Wilwerding, Terry M

    2009-01-01

    The current study examined the effect of different enamel conditioning times on surface roughness and bond strength using an etch-and-rinse system and four self-etch adhesives. Surface roughness (Ra...

  20. Veterans Health Administration Timely and Effective Care Data

    Data.gov (United States)

    U.S. Department of Health & Human Services — A list of VHA hospitals with timely and effective care (process of care) measure data. VHA collects this information through a Quality Improvement Organization...

  1. The effects of prepulse inhibition timing on the startle reflex and reaction time.

    Science.gov (United States)

    Maslovat, Dana; Kennedy, Paul M; Forgaard, Christopher J; Chua, Romeo; Franks, Ian M

    2012-04-04

    A loud acoustic stimulus has been shown to provoke a reflexive startle response and accelerate simple reaction times. However, an auditory prepulse presented in advance of a startling stimulus can reduce the effect of the startling stimulus. The current study examined the effect of the timing of the prepulse on startle-induced reaction times and the startle reflex. The task was to perform a 30° arm extension movement in response to a visual "go" stimulus. On selected trials, an auditory prepulse (80dB) was presented either 100ms, 500ms or 1000ms prior to the "go" signal. In addition, an auditory startling stimulus (124dB) was presented in conjunction with the "go" signal on some trials. Our results indicated that an auditory prepulse presented 100ms, and to a lesser extent 500ms, significantly decreased the amplitude of the startle reflex; however, the reaction time acceleration associated with the startling acoustic stimulus (SAS) was unaffected. The differential effect of the prepulse on the startle reflex and reaction time acceleration confirm different neural pathways for these effects while the differential effect of the prepulse on the control and startle RTs suggest different mechanisms for movement initiation. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  2. Weak microlensing effect and stability of pulsar time scale

    CERN Document Server

    Pshirkov, M S

    2006-01-01

    An influence of the weak microlensing effect on the pulsar timing is investigated for pulsar B1937+21. Average residuals of Time of Arrival (TOA) due to the effect would be as large as 10 ns in 20 years observation span. These residuals can be much greater (up to 1 ms in 20 years span) if pulsar is located in globular cluster (or behind it).

  3. Photoelectric Effect for Twist-deformed Space-time

    Science.gov (United States)

    Daszkiewicz, M.

    In this article, we investigate the impact of twisted space-time on the photoelectric effect, i.e., we derive the $\\theta$-deformed threshold frequency. In such a way we indicate that the space-time noncommutativity strongly enhances the photoelectric process.

  4. Modeling dynamic effects of promotion on interpurchase times

    NARCIS (Netherlands)

    D. Fok (Dennis); R. Paap (Richard); Ph.H.B.F. Franses (Philip Hans)

    2002-01-01

    textabstractIn this paper we put forward a duration model to analyze the dynamic effects of marketing-mix variables on interpurchase times. We extend the accelerated failure-time model with an autoregressive structure. An important feature of our model is that it allows for different long-run and

  5. Modeling dynamic effects of promotion on interpurchase times

    NARCIS (Netherlands)

    D. Fok (Dennis); R. Paap (Richard); Ph.H.B.F. Franses (Philip Hans)

    2002-01-01

    textabstractIn this paper we put forward a duration model to analyze the dynamic effects of marketing-mix variables on interpurchase times. We extend the accelerated failure-time model with an autoregressive structure. An important feature of our model is that it allows for different long-run and

  6. Wind Effects on Retention Time in Highway Ponds

    DEFF Research Database (Denmark)

    Bentzen, Thomas Ruby; Larsen, Torben; Rasmussen, Michael R.

    2008-01-01

    is to evaluate the quality of long term simulations based on historical rain series of the pollutant discharges from roads and highways. The idea of this paper is to evaluate the effects of wind on the retention time and compare the retention time for the situation of a spatial uniform wind shear stress...

  7. Photoelectric effect for twist-deformed space-time

    CERN Document Server

    Daszkiewicz, Marcin

    2016-01-01

    In this article, we investigate the impact of twisted space-time on the photoelectric effect, i.e., we derive the $\\theta$-deformed threshold frequency. In such a way we indicate that the space-time noncommutativity strongly enhances the photoelectric process.

  8. Chronic kisspeptin administration stimulated gonadal development in pre-pubertal male yellowtail kingfish (Seriola lalandi; Perciformes) during the breeding and non-breeding season.

    Science.gov (United States)

    Nocillado, Josephine N; Zohar, Yonathan; Biran, Jakob; Levavi-Sivan, Berta; Elizur, Abigail

    2013-09-15

    The kisspeptin system is now accepted as a key regulator of vertebrate reproductive function, particularly the onset of puberty. In teleosts, the stimulatory effect of exogenous kisspeptins has been demonstrated mainly at the hypothalamic and pituitary levels of the reproductive axis, with very limited information pertaining to gonadal response. We determined the effect of chronic peripheral administration of the conserved kisspeptin decapeptides (YNLNSFGLRY or Kiss1-10; and FNFNPFGLRF or Kiss2-10) on gonadal development of pre-pubertal yellowtail kingfish (Seriola lalandi), a Perciform teleost, during the breeding and non-breeding season. We utilized slow-release implants to chronically deliver the synthesized peptides, which were based on the yellowtail kingfish kiss1 and kiss2 cDNA sequences that we isolated. The expression level of kiss2r and gnrh1 in the brain or hypothalamus did not vary between treated and control groups. Pituitary expression of fshβ and lhβ was upregulated only with Kiss1-10 treatment regardless of the season. Based on histological evidence, gonadal development was stimulated in male fish with either Kiss1-10 or Kiss2-10, with Kiss2-10 being more effective during the non-breeding period. Overall, our results suggest that kisspeptins modulate the early gonadal development of male yellowtail kingfish, however that may vary with the breeding season.

  9. Effective Maxwell Equations from Time-dependent Density Functional Theory

    Institute of Scientific and Technical Information of China (English)

    Weinan E; Jianfeng LU; Xu YANG

    2011-01-01

    The behavior of interacting electrons in a perfect crystal under macroscopic external electric and magnetic fields is studied. Effective Maxwell equations for the macroscopic electric and magnetic fields are derived starting from time-dependent density functional theory. Effective permittivity and permeability coefficients are obtained.

  10. "Fast" Is Not "Real-Time": Designing Effective Real-Time AI Systems

    Science.gov (United States)

    O'Reilly, Cindy A.; Cromarty, Andrew S.

    1985-04-01

    Realistic practical problem domains (such as robotics, process control, and certain kinds of signal processing) stand to benefit greatly from the application of artificial intelligence techniques. These problem domains are of special interest because they are typified by complex dynamic environments in which the ability to select and initiate a proper response to environmental events in real time is a strict prerequisite to effective environmental interaction. Artificial intelligence systems developed to date have been sheltered from this real-time requirement, however, largely by virtue of their use of simplified problem domains or problem representations. The plethora of colloquial and (in general) mutually inconsistent interpretations of the term "real-time" employed by workers in each of these domains further exacerbates the difficul-ties in effectively applying state-of-the-art problem solving tech-niques to time-critical problems. Indeed, the intellectual waters are by now sufficiently muddied that the pursuit of a rigorous treatment of intelligent real-time performance mandates the redevelopment of proper problem perspective on what "real-time" means, starting from first principles. We present a simple but nonetheless formal definition of real-time performance. We then undertake an analysis of both conventional techniques and AI technology with respect to their ability to meet substantive real-time performance criteria. This analysis provides a basis for specification of problem-independent design requirements for systems that would claim real-time performance. Finally, we discuss the application of these design principles to a pragmatic problem in real-time signal understanding.

  11. Audio Effects Based on Biorthogonal Time-Varying Frequency Warping

    Directory of Open Access Journals (Sweden)

    Cavaliere Sergio

    2001-01-01

    Full Text Available We illustrate the mathematical background and musical use of a class of audio effects based on frequency warping. These effects alter the frequency content of a signal via spectral mapping. They can be implemented in dispersive tapped delay lines based on a chain of all-pass filters. In a homogeneous line with first-order all-pass sections, the signal formed by the output samples at a given time is related to the input via the Laguerre transform. However, most musical signals require a time-varying frequency modification in order to be properly processed. Vibrato in musical instruments or voice intonation in the case of vocal sounds may be modeled as small and slow pitch variations. Simulation of these effects requires techniques for time-varying pitch and/or brightness modification that are very useful for sound processing. The basis for time-varying frequency warping is a time-varying version of the Laguerre transformation. The corresponding implementation structure is obtained as a dispersive tapped delay line, where each of the frequency dependent delay element has its own phase response. Thus, time-varying warping results in a space-varying, inhomogeneous, propagation structure. We show that time-varying frequency warping is associated to an expansion over biorthogonal sets generalizing the discrete Laguerre basis. Slow time-varying characteristics lead to slowly varying parameter sequences. The corresponding sound transformation does not suffer from discontinuities typical of delay lines based on unit delays.

  12. The effects of the framing of time on delay discounting.

    Science.gov (United States)

    DeHart, William Brady; Odum, Amy L

    2015-01-01

    We examined the effects of the framing of time on delay discounting. Delay discounting is the process by which delayed outcomes are devalued as a function of time. Time in a titrating delay discounting task is often framed in calendar units (e.g., as 1 week, 1 month, etc.). When time is framed as a specific date, delayed outcomes are discounted less compared to the calendar format. Other forms of framing time; however, have not been explored. All participants completed a titrating calendar unit delay-discounting task for money. Participants were also assigned to one of two delay discounting tasks: time as dates (e.g., June 1st, 2015) or time in units of days (e.g., 5000 days), using the same delay distribution as the calendar delay-discounting task. Time framed as dates resulted in less discounting compared to the calendar method, whereas time framed as days resulted in greater discounting compared to the calendar method. The hyperboloid model fit best compared to the hyperbola and exponential models. How time is framed may alter how participants attend to the delays as well as how the delayed outcome is valued. Altering how time is framed may serve to improve adherence to goals with delayed outcomes.

  13. Time series trends of the safety effects of pavement resurfacing.

    Science.gov (United States)

    Park, Juneyoung; Abdel-Aty, Mohamed; Wang, Jung-Han

    2017-04-01

    This study evaluated the safety performance of pavement resurfacing projects on urban arterials in Florida using the observational before and after approaches. The safety effects of pavement resurfacing were quantified in the crash modification factors (CMFs) and estimated based on different ranges of heavy vehicle traffic volume and time changes for different severity levels. In order to evaluate the variation of CMFs over time, crash modification functions (CMFunctions) were developed using nonlinear regression and time series models. The results showed that pavement resurfacing projects decrease crash frequency and are found to be more safety effective to reduce severe crashes in general. Moreover, the results of the general relationship between the safety effects and time changes indicated that the CMFs increase over time after the resurfacing treatment. It was also found that pavement resurfacing projects for the urban roadways with higher heavy vehicle volume rate are more safety effective than the roadways with lower heavy vehicle volume rate. Based on the exploration and comparison of the developed CMFucntions, the seasonal autoregressive integrated moving average (SARIMA) and exponential functional form of the nonlinear regression models can be utilized to identify the trend of CMFs over time. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Transcript levels of genes implicated in steroidogenesis in the testes and fat tissue in relation to androstenone accumulation in fat of pubertal pigs.

    Science.gov (United States)

    Robic, A; Feve, K; Riquet, J; Prunier, A

    2016-10-01

    The present study was performed to measure messenger RNA levels of steroidogenic enzymes in testes and fat tissue and determine whether they are related to fat androstenone level. Real-time polymerase chain reaction experiments were performed on 26 testes and 12 adipose tissue samples from pubertal boars using 21 genes. The absence of significant correlations between fat androstenone and the transcriptional activity of the SRD5A2 and SRD5A3 genes but the high correlation coefficient with that of the SRD5A1 gene (r = 0.62, P fat concentration of androstenone (0.57 fat is related to the production in testes of androstenone and more generally to all sex steroids. Altogether, our data are in favor of a preponderant role of AKR1C-pig6 instead of HSD17B3 for testicular synthesis of steroids. Concerning fat tissue, our data do not support a significant de novo biosynthesis of steroids in porcine adipose tissues. The presence of transcripts coding for steroid enzymes, especially those of AKR1C-pig6, suggests that steroids can be transformed. None of transcript abundance was related to androstenone accumulation (P > 0.1). Therefore, steroids synthesized elsewhere can be transformed in fat tissue but synthesis of androstenone is unlikely.

  15. Effects of moment of inertia on simple reaction time.

    Science.gov (United States)

    Anson, J G

    1989-03-01

    Two experiments examined the effect of altering the moment of inertia within an anatomical unit on simple reaction time (SRT), premotor time (PMT), and motor time (MOT) during the initiation of a discrete rapid movement. In Experiment 1 (N = 14), moment of inertia of the forearm was increased with the addition of a weighted cuff fastened around the wrist. In Experiment 2 (N = 7), moment of inertia was altered by the addition of a weighted sleeve to the index finger prior to rapid extension of the digit. Results from both experiments were unequivocal. An increase in the moment of inertia resulted in a significant increase in SRT and MOT but had no significant effect on PMT. Within selected anatomical unites (forearm and index finger), an increase in the moment of inertia does not appear to require additional neuromotor programming time but does influence the overall duration of response initiation.

  16. Effective field theory in time-dependent settings

    CERN Document Server

    Collins, Hael; Ross, Andreas

    2012-01-01

    We use the in-in or Schwinger-Keldysh formalism to explore the construction and interpretation of effective field theories for time-dependent systems evolving out of equilibrium. Starting with a simple model consisting of a heavy and a light scalar field taken to be in their free vacuum states at a finite initial time, we study the effects from the heavy field on the dynamics of the light field by analyzing the equation of motion for the expectation value of the light background field. New terms appear which cannot arise from a local action of an effective field theory in terms of the light field, though they disappear in the adiabatic limit. We discuss the origins of these terms as well as their possible implications for time dependent situations such as inflation.

  17. Depressive realism: effects of depression severity and interpretation time.

    Science.gov (United States)

    McKendree-Smith, N; Scogin, F

    2000-12-01

    This study examined the theory of depressive realism, which posits that depressed people often are more accurate in perceptions and judgments than nondepressed people. Two possible qualifications to this theory were examined: (1) severity of depression moderates the effect, and (2) length of processing time will impact the presence of bias in depressed people, that is, negative bias will develop over time. College students were presented with a bogus personality profile that actually consisted of items previously rated as neutral in desirability. Participants rated these profiles for desirability initially and then again three days later. Results indicated a significant effect of depression severity on desirability rating. Nondepressed and mildly depressed students found their profiles to be more positive than the moderately/severely depressed students, with both groups having scores in the positive range. However, those participants who were moderately/severely depressed showed a negative bias in their ratings. No support was found for the effect of different times of interpretation.

  18. Sexually dimorphic innate immunological responses of pre-pubertal Brahman cattle following an intravenous lipopolysaccharide challenge.

    Science.gov (United States)

    Carroll, Jeffery A; Burdick Sanchez, Nicole C; Hulbert, Lindsey E; Ballou, Michael A; Dailey, Jeffery W; Caldwell, Lisa C; Vann, Rhonda C; Welsh, Thomas H; Randel, Ronald D

    2015-08-15

    This study was designed to characterize potential sexually dimorphic immunological responses following a lipopolysaccharide (LPS) challenge in beef cattle. Six female (heifers) and five male (bulls) Brahman calves (average age=253 ± 19.9 and 288 ± 47.9 days; average body weight=194 ± 11 kg and 247 ± 19 kg for heifers and bulls, respectively) were challenged with LPS (0.25 μg LPS/kg body weight). Following administration of LPS, all cattle displayed increased sickness behavior beginning at 0.5h, with heifers on average displaying less sickness behavior than bulls. A febrile response was observed in all animals following LPS administration, with a maximum response observed from 4 to 5.5h. The average rectal temperature response was greater in heifers than bulls. In all cattle there were elevated serum concentrations of cortisol from 0.5 to 8h, TNF-α from 1 to 2.5h, IL-6 from 2 to 8h, and IFN-γ from 2.5 to 7h after LPS challenge. Additionally, serum concentrations of TNF-α were greater in heifers than bulls from 1.5 to 2h after the LPS challenge. Concentrations of IFN-γ were also greater on average in bulls than heifers. Leukopenia occurred from 1 to 8h, with a decreased neutrophil to lymphocyte ratio for the first 5h among all calves. These data demonstrate the existence of a sexually dimorphic acute-phase response in pre-pubertal Brahman calves. Specifically, heifers may have a more robust acute response to LPS challenge, even though bulls display more signs of sickness. Published by Elsevier B.V.

  19. Body trunk fat and insulin resistance in post-pubertal obese adolescents

    Directory of Open Access Journals (Sweden)

    Luana Caroline dos Santos

    Full Text Available CONTEXT AND OBJECTIVE: Insulin resistance is a metabolic disorder commonly associated with excess body fat accumulation that may increase chronic disease risk. The present study was undertaken to evaluate the relationship between body composition and insulin resistance among obese adolescents. DESIGN AND SETTING: Cross-sectional study, at the Adolescence Center, Pediatric Department, Universidade Federal de São Paulo. METHODS: Body composition was assessed using dual-energy X-ray absorptiometry. Dietary intake was evaluated using a three-day dietary record. The biochemical evaluation comprised glucose, insulin, serum lipid, leptin and ghrelin measurements. Insulin resistance was calculated by means of the homeostasis model assessment of insulin resistance (HOMA-IR. RESULTS: Forty-nine post-pubertal obese adolescents participated in the study: 12 boys and 37 girls of mean age 16.6 (1.4 years and mean body mass index (BMI of 35.0 (3.9 kg/m². The mean glucose, insulin and HOMA values were 90.3 (6.4 mg/dl, 16.6 (8.1 µIU/ml and 3.7 (1.9, respectively. Hyperinsulinemia and insulin resistance were observed in 40.2% and 57.1% of the subjects, respectively. Adolescents with insulin resistance had higher BMI and body trunk fat. There was a trend towards higher leptin concentration in obese individuals with insulin resistance. Insulin resistance was positively correlated with body trunk fat, BMI, body fat mass (kg, leptin and body fat percentage. Furthermore, there was a negative correlation between HOMA-IR and lean body mass. The body composition predicted 30% of the HOMA-IR levels, according to linear regression models. CONCLUSION: Body trunk fat was significantly associated with insulin resistance, demonstrating the clinical importance of abdominal obesity during adolescence.

  20. A Possible Link Between the Pubertal Growth of Girls and Ovarian Cancer in Their Daughters

    Science.gov (United States)

    BARKER, DAVID J. P.; OSMOND, CLIVE; THORNBURG, KENT L.; KAJANTIE, EERO; ERIKSSON, JOHAN G.

    2017-01-01

    At puberty, the distance between the iliac crests of the female pelvis, measured by the intercristal and interspinous diameters, increases rapidly. This is mainly controlled by estrogens. We have followed up 6,370 women who were born in Helsinki during 1934–1944, and whose mothers’ pelvic bones were measured during routine antenatal care. We have previously reported that women whose mothers had larger intercristal diameters had higher rates of breast cancer. We postulated that large intercristal diameters are markers of high circulating concentrations of estrogen, which are established at puberty, persist through reproductive life and cause genetic instability in differentiating breast cells in female embryos. We now report on ovarian cancer in the same cohort. Our hypothesis was that the risk of this cancer would also be higher in women whose mothers had broader hips. We found that, when compared with all other women, the hazard ratio for ovarian cancer was 3.3 (95% CI 1.6–7.0, P = 0.004) in the daughters of mothers whose interspinous diameter was greater than 27 cm. Among mothers who had an early menarche, each measure of broad hips was associated with increased risk of ovarian cancer in their daughters. We postulate that ovarian cancer is initiated by exposure of the fetal ovary to maternal sex hormones. Concentrations of these hormones may be higher in mothers who had an early menarche. The maternal sex hormone profile that initiates ovarian cancer may be the product of poor nutrition and growth in early childhood followed by catch-up pre-pubertal growth. PMID:18461601

  1. Relaxation therapy for insomnia: nighttime and day time effects.

    Science.gov (United States)

    Means, M K; Lichstein, K L; Epperson, M T; Johnson, C T

    2000-07-01

    We compared day time functioning in college students with and without insomnia and explored changes in day time functioning after progressive relaxation (PR) treatment for insomnia. Students with insomnia (SWI; n = 57) were compared to a control group of students not complaining of insomnia (SNI; n = 61) on self-reported sleep variables and five questionnaires: Insomnia Impact Scale (IIS), Dysfunctional Beliefs and Attitudes About Sleep Scale (DBAS), Epworth Sleepiness Scale (ESS), Fatigue Severity Scale (FSS), and Penn State Worry Questionnaire (PSWQ). SWI demonstrated significant impairment on all day time functioning and sleep measures compared to SNI. To investigate treatment effects on day time functioning, 28 SWI were randomly assigned to PR. Treated SWI were compared to untreated SWI and SNI at posttreatment. Treated participants improved sleep in comparison to untreated SWI, but failed to show significant improvements in day time functioning. Insomnia treatments focused on improving sleep may not improve day time functioning, or day time gains may emerge more slowly than sleep gains. This study documents the wide range of day time functioning complaints in young adults with insomnia and suggests that the goal of insomnia treatment should be to not only improve sleep but also to improve the subjective experience of day time functioning.

  2. Tunable delay time and Hartman effect in graphene magnetic barriers

    Energy Technology Data Exchange (ETDEWEB)

    Ban, Yue; Wang, Lin-Jun [School of Materials Science and Engineering, Shanghai University, Shanghai 200444 (China); Chen, Xi, E-mail: xchen@shu.edu.cn [Department of Physics, Shanghai University, Shanghai 200444 (China)

    2015-04-28

    Tunable group delay and Hartman effect have been investigated for massless Dirac electrons in graphene magnetic barriers. In the presence of magnetic field, dwell time is found to be equal to net group delay plus the group delay contributing from the lateral shifts. The group delay times are discussed in both cases of normal and oblique incidence, to clarify the nature of Hartman effect. In addition, the group delay in transmission can be modulated from subluminality to superluminality by adjusting the magnetic field, which may also lead to potential applications in graphene-based microelectronics.

  3. Effective decay time of CF4 secondary scintillation

    Science.gov (United States)

    Margato, L. M. S.; Morozov, A.; Fraga, M. M. F. R.; Pereira, L.; Fraga, F. A. F.

    2013-07-01

    We report on the time evolution of CF4 secondary scintillation in the pressure range from 1 to 5 bar. Two types of MSGC plates were used for generation of the secondary scintillation in electron avalanches. Time spectra of the scintillation were recorded using several broadband and interference filters in the wavelength range from 220 to 800 nm. The visible emission (450-800 nm) shows a mono-exponential profile with a decay time of ~ 15 ns. The UV emission (220-450 nm) exhibits two components. The fast component has an effective decay time ranging from ~ 2 ns (1 bar) to ~ 10 ns (3-5 bar), while the slow component shows a decay time of ~ 40 ns. The slow component accounts for not more than 10% of the integrated UV emission intensity.

  4. Hypersurface-deformation algebroids and effective space-time models

    CERN Document Server

    Bojowald, Martin; Buyukcam, Umut; D'Ambrosio, Fabio

    2016-01-01

    In canonical gravity, covariance is implemented by brackets of hypersurface-deformation generators forming a Lie algebroid. Lie algebroid morphisms therefore allow one to relate different versions of the brackets that correspond to the same space-time structure. An application to examples of modified brackets found mainly in models of loop quantum gravity can in some cases map the space-time structure back to the classical Riemannian form after a field redefinition. For one type of quantum corrections (holonomies), signature change appears to be a generic feature of effective space-time, and is shown here to be a new quantum space-time phenomenon which cannot be mapped to an equivalent classical structure. In low-curvature regimes, our constructions prove the existence of classical space-time structures assumed elsewhere in models of loop quantum cosmology, but also shows the existence of additional quantum corrections that have not always been included.

  5. Effective time management: surgery, research, service, travel, fitness, and family.

    Science.gov (United States)

    Porta, C Rees; Anderson, Michael R; Steele, Scott R

    2013-12-01

    Over 1,500 years ago, the St. Benedictine Monks used planning and strict schedules to increase their productivity. Since then, surgeons have developed several different strategies to manage our time effectively. Finding a balance among career, family, and hobbies is essential for maintaining satisfaction and optimizing productivity. Several recurring themes throughout the medical literature offer potential solutions to help maximize the little time surgeons possess. In this article, we will explore some of the methods and strategies available to help surgeons minimize waste and make the most of the most precious commodity we have-our time.

  6. Effects of the switching time in OPS/OBS networks

    Institute of Scientific and Technical Information of China (English)

    Harald (φ)verby; Norvald Stol

    2004-01-01

    In this paper we present an analytical model, which considers the effects of the switching time on the network performance in service differentiated optical packet/burst switching (OPS/OBS) networks. Our results indicate that the switching time must be less than 10 % of the packet/burst duration in order to avoid any significant reductions in the network performance. Furthermore, regarding a network with full wavelength conversion, we show that the benefits of statistical resource sharing are almost non-existent for low priority traffic when the switching time is large.

  7. Effects of etching time on enamel bond strengths.

    Science.gov (United States)

    Triolo, P T; Swift, E J; Mudgil, A; Levine, A

    1993-12-01

    This study evaluated the effects of etching time on bond strengths of composite to enamel. Proximal surfaces of extracted molars were etched with either a conventional etchant (35% phosphoric acid) or one of two dentin/enamel conditioners, 10% maleic acid (Scotchbond Multi-Purpose Etchant), or a solution of oxalic acid, aluminum nitrate, and glycine (Gluma 1 & 2 Conditioner). Each agent was applied for 15, 30, or 60 seconds. Specimens etched with 35% phosphoric acid had the highest mean bond strengths at each etching time. At the manufacturer's recommended application times, the other two agents gave significantly lower shear bond strengths than phosphoric acid.

  8. Transit-Time Spin Field-Effect-Transistor

    OpenAIRE

    Appelbaum, Ian; Monsma, Douwe

    2007-01-01

    We propose and analyze a four-terminal metal-semiconductor device that uses hot-electron transport through thin ferromagnetic films to inject and detect a charge-coupled spin current transported through the conduction band of an arbitrary semiconductor. This provides the possibility of realizing a spin field-effect-transistor in Si, using electrostatic transit-time control in a perpendicular magnetic field, rather than Rashba effect with spin-orbit interaction.

  9. Risking it for Love: Romantic Relationships and Early Pubertal Development Confer Risk for later Disruptive Behavior Disorders in African-American Girls Receiving Psychiatric Care

    Science.gov (United States)

    Rodriguez, Erin M.; Nichols, Sara; Emerson, Erin; Donenberg, Geri R.

    2014-01-01

    Disruptive behavior problems (DBP) represent a growing concern for young women (e.g., Snyder & Sickmund, 2006), but gender-specific investigations have been traditionally underrepresented in this area. The purpose of this study is to examine the associations among gender-relevant risk factors for DBP among 217 African American girls in psychiatric care. African American girls, 12–16 years old (M=14.6; SD=1.2), and their primary female caregivers (N=254) were recruited from outpatient mental health clinics and reported on girls’ DBP, heterosexual dating experiences (romantic and sexual), peer relationships, pubertal development, and self-silencing at baseline, 6-, and 12-months. Structural Equation Modeling examined evidence for full versus mediated (via self-silencing) models and the structural relationships (direct and indirect) among key study variables. Results suggest that the full model was a significantly better fit than the mediated model as indicated by a Chi-squared difference test (p girls. Indirect effects analyses suggested that girls’ suppression of relational needs, assessed through a measure of self-silencing, explained the association between peer relationships and DBP. Findings highlight the importance of the relational context for girls’ DBP, with treatment implications supporting relationship-based models of care, early intervention, and skill building around negotiating needs with peers and partners. PMID:24748499

  10. EFFECT OF GENDER DIFFERENCE ON BRAKE REACTION TIME

    Directory of Open Access Journals (Sweden)

    Ashok

    2016-02-01

    Full Text Available BACKGROUND OF THE STUDY Reaction time is the time taken to respond to a stimulus or change in the environment. It is a method to assess the time taken from the perception of a stimulus followed by mental processing for a motor response. Reaction time in various day to day activities as in driving a car is very important. Brake reaction time (BRT is the time taken for the driver to respond to visualize an object and to press the brake pedal. It is affected by many features like age, gender, neuromuscular disorders. OBJECTIVE OF THE STUDY Study has been undertaken to compare the BRT in male and female drivers and to analyze the effect of sex difference on Brake reaction time. MATERIALS & METHODS Male and female subjects between the age group of 25 – 35 years with driving license were included. Study is conducted in a stationary car. An in-house built; braking timer is fixed to the electric circuit of the braking system in the car. This device is wirelessly connected to the reaction time software installed in the laptop. The subject is instructed to press the brake pedal when the light changed from red to green in the laptop screen. 5 readings are taken and the mean BRT is recorded. STATISTICAL ANALYSIS & RESULTS Statistical analysis done with unpaired student t test indicates that the BRT was more in the females than the males and was statistically significant (p value - 0007. CONCLUSION Gender difference has a significant effect on BRT and reaction time in female is longer than for the males.

  11. Quantifying Airborne Induced Polarization effects in helicopter time domain electromagnetics

    Science.gov (United States)

    Macnae, James

    2016-12-01

    This paper derives the Airborne Induced Polarization (AIP) response of an airborne electromagnetic (AEM) system to a horizontal, thin sheet conductor. A vertical component double-dipole approximates helicopter systems with towed concentric horizontal transmitter and receiver loops in frequency- or time-domain. In time domain, the AIP effect typically shows up as late-time negative data with amplitude 4 to 5 orders of magnitude smaller than the early-time peak of the positive AEM responses. Because of limited bandwidth from the short sample time after the decay of inductive responses, accurate extraction of intrinsic AIP parameters other than a minimum chargeability is almost impossible. Modelling further suggests that AIP effects in double-dipole AEM systems can only be reliably detected from polarizable material in the top few tens of metres. A titanium mineral exploration case history from the Lac Brûlé area, Quebec, Canada illustrates strong spatial coherence of AIP minimum chargeability estimates and their independence from other effects such as conductivity and magnetic susceptibility.

  12. Sex effects in mouse prion disease incubation time.

    Directory of Open Access Journals (Sweden)

    Shaheen Akhtar

    Full Text Available Prion disease incubation time in mice is determined by many factors including PrP expression level, Prnp alleles, genetic background, prion strain and route of inoculation. Sex differences have been described in age of onset for vCJD and in disease duration for both vCJD and sporadic CJD and have also been shown in experimental models. The sex effects reported for mouse incubation times are often contradictory and detail only one strain of mice or prions, resulting in broad generalisations and a confusing picture. To clarify the effect of sex on prion disease incubation time in mice we have compared male and female transmission data from twelve different inbred lines of mice inoculated with at least two prion strains, representing both mouse-adapted scrapie and BSE. Our data show that sex can have a highly significant difference on incubation time. However, this is limited to particular mouse and prion strain combinations. No sex differences were seen in endogenous PrP(C levels nor in the neuropathological markers of prion disease: PrP(Sc distribution, spongiosis, neuronal loss and gliosis. These data suggest that when comparing incubation times between experimental groups, such as testing the effects of modifier genes or therapeutics, single sex groups should be used.

  13. Deriving dynamic marketing effectiveness from econometric time series models

    NARCIS (Netherlands)

    C. Horváth (Csilla); Ph.H.B.F. Franses (Philip Hans)

    2003-01-01

    textabstractTo understand the relevance of marketing efforts, it has become standard practice to estimate the long-run and short-run effects of the marketing-mix, using, say, weekly scanner data. A common vehicle for this purpose is an econometric time series model. Issues that are addressed in the

  14. "Deflategate": Time, Temperature, and Moisture Effects on Football Pressure

    Science.gov (United States)

    Blumenthal, Jack; Beljak, Lauren; Macatangay, Dahlia-Marie; Helmuth-Malone, Lilly; McWilliams, Catharina; Raptis, Sofia

    2016-01-01

    In a recent paper in "The Physics Teacher (TPT)", DiLisi and Rarick used the National Football League "Deflategate" controversy to introduce to physics students the physics of a bouncing ball. In this paper, we measure and analyze the environmental effects of time, ambient temperature, and moisture on the internal pressure of…

  15. Analysis of Complex Intervention Effects in Time-Series Experiments.

    Science.gov (United States)

    Bower, Cathleen

    An iterative least squares procedure for analyzing the effect of various kinds of intervention in time-series data is described. There are numerous applications of this design in economics, education, and psychology, although until recently, no appropriate analysis techniques had been developed to deal with the model adequately. This paper…

  16. "Deflategate": Time, Temperature, and Moisture Effects on Football Pressure

    Science.gov (United States)

    Blumenthal, Jack; Beljak, Lauren; Macatangay, Dahlia-Marie; Helmuth-Malone, Lilly; McWilliams, Catharina; Raptis, Sofia

    2016-01-01

    In a recent paper in "The Physics Teacher (TPT)", DiLisi and Rarick used the National Football League "Deflategate" controversy to introduce to physics students the physics of a bouncing ball. In this paper, we measure and analyze the environmental effects of time, ambient temperature, and moisture on the internal pressure of…

  17. Modeling Fan Effects on the Time Course of Associative Recognition

    Science.gov (United States)

    Schneider, Darryl W.; Anderson, John R.

    2012-01-01

    We investigated the time course of associative recognition using the response signal procedure, whereby a stimulus is presented and followed after a variable lag by a signal indicating that an immediate response is required. More specifically, we examined the effects of associative fan (the number of associations that an item has with other items…

  18. Time-dependent effects of cardiovascular exercise on memory

    DEFF Research Database (Denmark)

    Roig, Marc; Thomas, Richard; Mang, Cameron S

    2016-01-01

    We present new evidence supporting the hypothesis that the effects of cardiovascular exercise on memory can be regulated in a time-dependent manner. When the exercise stimulus is temporally coupled with specific phases of the memory formation process, a single bout of cardiovascular exercise may ...

  19. Stability on time-dependent domains: convective and dilution effects

    Science.gov (United States)

    Krechetnikov, R.; Knobloch, E.

    2017-03-01

    We explore near-critical behavior of spatially extended systems on time-dependent spatial domains with convective and dilution effects due to domain flow. As a paradigm, we use the Swift-Hohenberg equation, which is the simplest nonlinear model with a non-zero critical wavenumber, to study dynamic pattern formation on time-dependent domains. A universal amplitude equation governing weakly nonlinear evolution of patterns on time-dependent domains is derived and proves to be a generalization of the standard Ginzburg-Landau equation. Its key solutions identified here demonstrate a substantial variety-spatially periodic states with a time-dependent wavenumber, steady spatially non-periodic states, and pulse-train solutions-in contrast to extended systems on time-fixed domains. The effects of domain flow, such as bifurcation delay due to domain growth and destabilization due to oscillatory domain flow, on the Eckhaus instability responsible for phase slips in spatially periodic states are analyzed with the help of both local and global stability analyses. A nonlinear phase equation describing the approach to a phase-slip event is derived. Detailed analysis of a phase slip using multiple time scale methods demonstrates different mechanisms governing the wavelength changing process at different stages.

  20. Effect of Noncommutativity of Space-time on Zitterbewegung

    CERN Document Server

    Verma, Ravikant

    2016-01-01

    In this paper, we present the result of our investigation on the modification of Zitterbewegung due to the noncommutativity of the space-time. First, we study the effect of noncommutativity of Moyal space-time on Zitterbewegung to find that the noncommutativity of Moyal space-time does not affect the Zitterbewegung. Secondly, we see the effect of $\\kappa$-deformation of the space-time on Zitterbewegung. For this, we start with the $\\kappa$-deformed Dirac theory and using $\\kappa$-deformed Dirac equation valid upto first order in deformation parameter $a$, we find the modified Zitterbewegung due to $\\kappa$-deformation of space-time valid upto first order in the deformation parameter $a$. In the limit $a\\rightarrow 0$, we get back the commutative result. And finally, we find the modification of the Zitterbewegung due to the Magueijo-Smolin approach of doubly special relativity(DSR) and in the limit $E_p \\rightarrow \\infty$, we get back the result in the commutative space-time.

  1. Contrasting effects of interference and of breaks in interval timing.

    Science.gov (United States)

    Gaudreault, Rémi; Fortin, Claudette; Macar, Françoise

    2010-01-01

    When a break is introduced during an interval to be timed, the interval is perceived shorter as break location is delayed. This is interpreted as a result of attention sharing between timing and monitoring the source of the break signal. Similar effects and interpretations are found in another context involving interfering tasks. Such tasks are assumed to induce transient interruptions in timing, comparable to those obtained with breaks. Break and interference conditions were contrasted in a temporal reproduction procedure with identical stimuli. Both conditions induced temporal underestimation and similar location effects. Similar trends occurred in a control condition where no processing of the interfering signal was required. The data suggest that expectancy, intentional processing, and automatic attraction of attention shorten temporal estimates.

  2. [The evaluating time of curative effect on sudden deafness].

    Science.gov (United States)

    Liu, Yangyun; Jiang, Wen; Mao, Kunhua; Chen, Qiong

    2012-04-01

    To explore the best evaluating time of curative effect on sudden deafness so that the curative effect on sudden deafness can been evaluated more exactly and literally. Pure tone audiometries in 112 cases of sudden deafness were performed on the pretreatment day and on the third, seventh, fourteenth post-treatment day, and in the first, second, third, fourth post-treatment month. All of acoustical data were analyzed. The total effective rates were statistical different between the third, seventh post-treatment day and the fourteenth post-treatment day, the first, second, third, fourth post-treatment month. There were no statistical difference between the fourteenth post-treatment day and the first post-treatment month. There were statistical difference between the fourteenth post-treatment day and the second, third, fourth post-treatment month. The total effective rates were no statistical difference between the first and the second, third, fourth post-treatment month but it was fluctuated in the first post-treatment month. The total effective rates were no statistical difference between the second and the third, fourth post-treatment month and it was changeless on the second post-treatment month. From the curve of recruitment of hearing in different time, the curve of the total effective rates ascend from the third post-treatment day, then get to plateau from the second post-treatment month. If the cure rates, the efficiency rates, the effective rates in different time were analyzed, respectively, the hearing improvement ascend in first two weeks then. Hearing improvement get to plateau from fourteenth post-treatment day. (1) The evaluated results of curative effect to sudden deafness correlated vary in different time point post-treatment. (2) Prognosis can be predicted approximately 2 weeks after treatment. Patients who recover acoustic sensibility within 2 weeks have more significant improvement than the patients who hearing improvement after 2 weeks treatment

  3. The Effects of Time on Soil Behaviour and Pile Capacity

    DEFF Research Database (Denmark)

    Augustesen, Anders

    this into account. This implies that the design methods used today do not in general make use of the full capacity of piles. This thesis is based on a number of scientific papers and reports that deal with elements of pile design and time effects in soils in general. With regard to pile design, focus is placed...... foundations. Further, design methods that take no account of time will be subject to considerable error unless they consider a tightly specified age range. Time functions (relation between time after installation and capacity), which have been offered for quantifying set-up for piles in clay, are investigated....... Therefore, the design of piles has remained a constant source of attention, especially with regard to the methodology for predicting the capacity. Three very different design methods for piles in both clay and sand are assessed by comparing predicted capacities with measured capacities from established...

  4. The Effects of Real-Time Interactive Multimedia Teleradiology System.

    Science.gov (United States)

    Al-Safadi, Lilac

    2016-01-01

    This study describes the design of a real-time interactive multimedia teleradiology system and assesses how the system is used by referring physicians in point-of-care situations and supports or hinders aspects of physician-radiologist interaction. We developed a real-time multimedia teleradiology management system that automates the transfer of images and radiologists' reports and surveyed physicians to triangulate the findings and to verify the realism and results of the experiment. The web-based survey was delivered to 150 physicians from a range of specialties. The survey was completed by 72% of physicians. Data showed a correlation between rich interactivity, satisfaction, and effectiveness. The results of our experiments suggest that real-time multimedia teleradiology systems are valued by referring physicians and may have the potential for enhancing their practice and improving patient care and highlight the critical role of multimedia technologies to provide real-time multimode interactivity in current medical care.

  5. Effectiveness of timely intraoperative iodine irrigation during cataract surgery.

    Science.gov (United States)

    Matsuura, Kazuki; Miyazaki, Dai; Sasaki, Shin-Ichi; Yakura, Keiko; Inoue, Yoshitsugu; Sakamoto, Masako

    2016-11-01

    To determine the antiseptic efficacy of timely intraoperative iodine irrigation during cataract surgery. A total of 198 eyes of 99 cataract surgery patients were studied. The eyes were randomly assigned to treatment with or without timely intraoperative iodine irrigation of the surgical field with an iodine compound equivalent to 0.33 % povidone-iodine. In eyes in the timely intraoperative iodine irrigation group, the ocular surface was irrigated twice intraoperatively-before the initial incision and before insertion of the intraocular lens (IOL). The efficacy of the antiseptic treatment was evaluated by culture tests using scrapings of the surface of the sclerocornea and conjunctiva to the left of the incision and by broad-range real-time PCR for bacterial 16S ribosomal DNA using scrapings from the right side of the incision. Following intraoperative application of the iodine, bacteria were not detected in cultures of the samples. For the control eyes without timely iodine irrigation, cultures of samples from five and two eyes were positive before the initial incision and before IOL insertion, respectively. The bacterial DNA copy number before the initial incision was 1.7 ± 0.5 × 10(3), which was significantly lower than that of the control eyes (1.7 ± 0.6 × 10(4)). For both groups of eyes, the bacterial DNA copy number was significantly lower before the IOL insertion depending on the time course. When the antiseptic effect of the iodine irrigation and time course on bacterial DNA copy number was analyzed using generalized mixed linear regression, both were found to be significantly effective. No significant intraoperative epithelial defect was observed. The postoperative corneal endothelial cell count did not differ significantly between the two groups of eyes. Timely iodine irrigation can serve as a simple and useful adjunctive disinfection step in cataract surgery.

  6. An analytical description of rate effects in timing RPCs

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Diaz, D. [LabCaF, Departamento de Fisica de Particulas, Universidade de Santiago de Compostela, 15782, Santiago de Compostela (Spain)]. E-mail: diego@fpddux.usc.es; Fonte, P. [LIP, Departamento de Fisica, Universidade de Coimbra, 3004-516, Coimbra (Portugal); Instituto Superior de Engenharia de Coimbra, Rua Pedro Nunes, 3030-199, Coimbra (Portugal); Garzon, J.A. [LabCaF, Departamento de Fisica de Particulas, Universidade de Santiago de Compostela, 15782, Santiago de Compostela (Spain); Mangiarotti, A. [Physikalisches Institut der Universitaet Heidelberg, Philosophenweg 12, D-69120, Heidelberg (Germany)

    2006-08-15

    An analytical framework for describing the RPC behavior under high irradiation is proposed, including the effect of the fluctuations of the field. The description is compared with an equivalent MC and data for timing RPCs, showing good agreement. Moreover, the formalism allows to clearly identify the main variables ruling the process. By using the DC electric properties of the plates, the MC allows to reproduce the charging-up process in a dynamic situation, revealing that it takes place at the scale of the relaxation time, varying with the primary rate.

  7. Effects of Social Constraints on Career Maturity: The Mediating Effect of the Time Perspective

    Science.gov (United States)

    Kim, Kyung-Nyun; Oh, Se-Hee

    2013-01-01

    Previous studies have provided mixed results for the effects of social constraints on career maturity. However, there has been growing interest in these effects from the time perspective. Few studies have examined the effects of social constraints on the time perspective which in turn influences career maturity. This study examines the mediating…

  8. Effect of time zone and game time changes on team performance: National Football League.

    Science.gov (United States)

    Jehue, R; Street, D; Huizenga, R

    1993-01-01

    To determine the effect of time zone and game time changes on NFL team performance, win-loss records from 1978-1987 were analyzed. Twenty-seven NFL teams were grouped by time zone and possible anti-jet lag adjustments. Among all intra-time zone rivals, home teams won 56.6%, away teams won 43.8%, for a home vs away winning percentage change of -12.8% (P winning percentage was found to be 0.0% vs West teams, -14.1% vs Central teams (N = 8) (P zone, home vs away team winning percentage changed -23.8% (P winning percentages (75.0% and 68.4%) when playing Central and East teams, respectively, with little or no fall in away winning percentages (67.7% and 68.8%). For day games, a 3-h phase advance may decrease West coast team performance. In one small subset, anti-jet lag adjustments appeared to eliminate the expected decrement in performance. For night games, West coast teams, whether home or away, appear to be at a distinct advantage over East and Central teams.

  9. The Effect of Road Traffic Noise on Reaction Time

    Science.gov (United States)

    Alimohammadi, Iraj; Zokaei, Mojtaba; Sandrock, Stephan

    2015-01-01

    Background: Traffic noise is one of the main important sources in urban noise pollution, which causes various physiological and psychological effects that can cause disturbs in performance, sleep disturbances, hearing loss and impact on job performance. This study was conducted to verify the impact of road traffic noise on reaction time in terms of extraversion and sex. Methods: Traffic noise was measured and recorded in 10 arterial streets in Tehran, and then the recorded noise was emitted towards participants in an acoustic room. The participants were 80 (40 cases and 40 controls) students. Personality type was determined by Eysenck Personality Inventory (EPI) questioner. Reaction time before and after exposure to traffic noise was measured. Results: Reaction time before exposure to traffic noise did not differ (P=0.437) significantly between introverts and extraverts. However, it was increased significantly in both groups after exposure to traffic noise (PIntrovert’s reaction time was more increased than that of extraverts. Conclusion: Traffic noise augmented reaction time of both males and females. This study also revealed that exposure to traffic noise leads to increase in reaction time. PMID:26634199

  10. Effects of shifting time on pressure impact in hydraulic systems

    Institute of Scientific and Technical Information of China (English)

    ZHU Zhen-cai; CHEN Guo-an

    2005-01-01

    The limitations in existing measures for absorbing pressure impact in hydraulic systems were summarized in this paper. Based on the forming principle of the oil in a hydrostatic closed pressure chamber, the underlying reasons of the pressure impact were analyzed theoretically, the intrinsic laws that the extent of the pressure impact in hydraulic oil lines are affected by some factors, such as oil elastic modulus, oil line's geometrical volume, and changing rate of oil volume versus time etc, were discussed. Experimental investigations into pressure impact in all pressure chambers because of shifting were conducted under different working conditions by employing a special experimental system. The effects of shifting time on pressure impact were studied. A new concept with universal meaning, i.e. optimal shifting time, and its characterizing parameter and the methods of shifting at optimal shifting time were also proposed. The results show that shifting time lag △t is of rationality and maneuverablility. The higher the working pressure, the shorter the shifting time.

  11. Time-reversal-breaking induced quantum spin Hall effect

    Science.gov (United States)

    Luo, Wei; Shao, D. X.; Deng, Ming-Xun; Deng, W. Y.; Sheng, L.

    2017-01-01

    We show that quantum spin Hall (QSH) effect does not occur in a square lattice model due to cancellation of the intrinsic spin-orbit coupling coming from different hopping paths. However, we show that QSH effect can be induced by the presence of staggered magnetic fluxes alternating directions square by square. When the resulting Peierls phase takes a special value , the system has a composite symmetry ΘΡ− with Θ the time-reversal operator and Ρ− transforming the Peierls phase from γ to γ − , which protects the gapless edge states. Once the phase deviates from , the edge states open a gap, as the composite symmetry is broken. We further investigate the effect of a Zeeman field on the QSH state, and find that the edge states remain gapless for . This indicates that the QSH effect is immune to the magnetic perturbation. PMID:28220858

  12. Pubertal dependent effects of cadmium on episodic prolactin secretion in male rats

    Energy Technology Data Exchange (ETDEWEB)

    Lafuente, A.; Alvarez-Demanuel, E.; Marquez, N. [Fac. de Cienicas, Orense (Spain). Lab. de Toxicologia; Esquifino, A.I. [Dept. Bioquimica, Facultad de Medicina, Universidad Complutense, 28040-Madrid (Spain)

    1999-02-01

    This work was undertaken to assess if exposure to cadmium related to puberty may affect the episodic pattern of prolactin. Male rats were submitted to cadmium exposure, from day 30 to 60 or from day 60 to 90 of life respectively, at a dose of 50 ppm in the drinking water. Control age-matched rats received cadmium-free water. Prepubertal cadmium administration decreased mean serum prolactin levels and the absolute amplitude of the prolactin pulses. Subchronic exposure to cadmium of adult rats decreased mean serum prolactin levels, the absolute amplitude of the prolactin pulses and their duration, and the mean half-life of the hormone. These results suggest that subchronic cadmium exposure changes the secretory pattern of prolactin in adult male rats in a puberty-dependent way. (orig.) With 1 fig., 1 tab., 37 refs.

  13. Age and time effects on implicit and explicit learning.

    Science.gov (United States)

    Verneau, Marion; van der Kamp, John; Savelsbergh, Geert J P; de Looze, Michiel P

    2014-01-01

    BACKGROUND/STUDY CONTEXT: It has been proposed that effects of aging are more pronounced for explicit than for implicit motor learning. The authors evaluated this claim by comparing the efficacy of explicit and implicit learning of a movement sequence in young and older adults, and by testing the resilience against fatigue and secondary tasking after learning. It was also examined whether explicit learning in older adults can be promoted by alleviating time constraints during learning. The alternating serial reaction time task (ASRTT) was used. Experiment 1 compared the benefits of receiving full instructions about the stimulus sequence relative to receiving no instructions in young (20-25 years) and older (50-65 years) adults during retention and during transfer to fatigue and secondary task conditions. Experiment 2 alleviated time constraints during the initial bouts of practice with full instructions. Experiment 1 indicated that the older adults learned on the ASRTT and achieved similar performance as young adults when no instructions were given. In contrast to the young adults, learning was not superior in older adults who received full instructions compared with those who did not. Experiment 2 indicated that alleviating time constraints allowed some of the older adults to gain from instruction but only under relatively low time constraints, but there was no retention with rigorous time constraints. Explicit learning, but not implicit learning, declines in older adults. This is partly due to older adults difficulties to apply explicit knowledge. Less rigorous time constraints can help to ameliorate some of these difficulties and may induce levels of explicit learning in older adults that will result in superior performance compared with implicit learning. Implicit learning did occur under time constraints that prevented explicit learning.

  14. Quantum gravity effects in Myers-Perry space-times

    CERN Document Server

    Litim, Daniel F

    2013-01-01

    We study quantum gravity effects for Myers-Perry black holes assuming that the leading contributions arise from the renormalization group evolution of Newton's coupling. Provided that gravity weakens following the asymptotic safety conjecture, we find that quantum effects lift a degeneracy of higher-dimensional black holes, and dominate over kinematical ones induced by rotation, particularly for small black hole mass, large angular momentum, and higher space-time dimensionality. Quantum-corrected space-times display inner and outer horizons, and show the existence of a black hole of smallest mass in any dimension. Ultra-spinning solutions no longer persist. Thermodynamic properties including temperature, specific heat, the Komar integrals, and aspects of black hole mechanics are studied as well. Observing a softening of the ring singularity, we also discuss the validity of classical energy conditions.

  15. Quantum gravity effects in Myers-Perry space-times

    Energy Technology Data Exchange (ETDEWEB)

    Litim, Daniel F.; Nikolakopoulos, Konstantinos [Department of Physics and Astronomy, University of Sussex,Falmer Campus, Brighton BN1 9QH (United Kingdom)

    2014-04-03

    We study quantum gravity effects for Myers-Perry black holes assuming that the leading contributions arise from the renormalization group evolution of Newton’s coupling. Provided that gravity weakens following the asymptotic safety conjecture, we find that quantum effects lift a degeneracy of higher-dimensional black holes, and dominate over kinematical ones induced by rotation, particularly for small black hole mass, large angular momentum, and higher space-time dimensionality. Quantum-corrected space-times display inner and outer horizons, and show the existence of a black hole of smallest mass in any dimension. Ultra-spinning solutions no longer persist. Thermodynamic properties including temperature, specific heat, the Komar integrals, and aspects of black hole mechanics are studied as well. Observing a softening of the ring singularity, we also discuss the validity of classical energy conditions.

  16. Time Scales and Tidal Effects in Minor Mergers

    Institute of Scientific and Technical Information of China (English)

    Yu Lu; Jian-Yan Wei

    2003-01-01

    We use controlled N-body simulation to investigate the dynamical processes (dynamical friction, tidal truncation, etc.) involved in the merging of small satellites into bigger halos. We confirm the validity of some analytic formulae proposed earlier based on simple arguments. For rigid satellites represented by softened point masses, the merging time scale depends on both the orbital shape and concentration of the satellite. The dependence on orbital ellipticity is roughly a power law, as suggested by Lacey & Cole, and the dependence on satellite concentration is similar to that proposed by White. When merging satellites are represented by non-rigid objects, Tidal effects must be considered. We found that material beyond the tidal radius are stripped off. The decrease in the satellite mass might mean an increase in the merging time scale, but in fact, the merging time is decreased,because the stripped-off material carries away a proportionately larger amount of of orbital energy and angular momentum.

  17. Temperature Effect and Correction Method of White Rabbit Timing Link

    CERN Document Server

    Li, Hongming; Pan, Weibin; Du, Qiang; Li, Jianmin

    2014-01-01

    To guarantee the angular resolution, the Large High Altitude Air Shower Observatory (LHAASO) requires a 500ps (rms) timing synchronization among the 6866 detect units for its KM2A sub-detector array. The White Rabbit technology is applied which combines sub-nanosecond precision timing transfer and gigabit Ethernet data transfer over the same fiber media. Deployed on a wild field at 4300m a.s.l. altitude, the WR network must maintain the precision over a wide temperature range. The temperature effect on a small WR link is measured, and contributions from different components like optical fiber, SFP module, fixed delay on PCB and ICs are separately studied and analyzed. An online real-time temperature correction method was applied based on the result which significantly reduce the synchronization variation from 300 ps to 50 ps in a temperature range of 50 degrees centigrade.

  18. The effect of Internet separation degree time sensitivity on transmission

    Institute of Scientific and Technical Information of China (English)

    ZHAO Hai; SU Wei-ji; XU Ye; ZHANG Xin

    2006-01-01

    Separation degree is a standard measure for complex network research.Whatever its scale or its increase makes the Interact take on a complex network character.Because of the development of complex network theory and the continuous evolution of the Internet,it is a key problem that uses complex network theory to research the Internet nowadays.In this paper,the Internet separation degree is put forward.The time series stochastic process model of the Internet separation degree is established.According to actual data,the Internet separation degree time sensitivity model (ISDTSM) is established and the effect of time sensitivity of the Internet separation degree to the Intemet IP level transmission is computed.Finally the Internet separation and IP transmission during 2008 Beijing Olympic Games were forecasted by using the model.

  19. Time of day effects on repeated sprint ability.

    Science.gov (United States)

    Zarrouk, N; Chtourou, H; Rebai, H; Hammouda, O; Souissi, N; Dogui, M; Hug, F

    2012-12-01

    The present study aimed at investigating the effects of time-of-day on muscle power and associated electromyographic (EMG) activity level of 4 thigh muscles during a repeated pedalling sprint exercise. After a familiarization session, 12 male subjects were asked to perform the repeated sprint ability test during 2 experimental sessions (randomized order), which were set up either at 06:00 or 18:00 h. For each sprint, peak power output, percentage of peak power decrement and total work were calculated. EMG activity of vastus lateralis, rectus femoris, vastus medialis and biceps femoris muscles was recorded throughout the test and analyzed for each sprint. Total work and percentage of peak power decrement were higher in the evening than in the morning (psprints (psprint 1 and psprint 2 and 3). There was no time-of-day effect for EMG activity level. The neuromuscular efficiency decreased significantly over the repeated sprint ability test at the 2 times of testing (prepeated sprint ability test, EMG activity of major thigh muscles was not time-of-day dependent. © Georg Thieme Verlag KG Stuttgart · New York.

  20. More about tunnelling times and superluminal tunnelling (Hartmann effect)

    Energy Technology Data Exchange (ETDEWEB)

    Olkhovsky, V.S. [Ukrainian Akademy of Sciences, Kiev (Ukraine). Inst. for Nuclear Research]|[INFN-Sezione di Catania (Italy); Recami, E. [Bergamo Univ. (Italy). Facolta` di Ingegneria]|[State Univ. at Campinas, Campinas (Brazil); Raciti, F. [Catania Univ. (Italy); Zaichenko, A. [Ukrainian Akademy of Sciences, Kiev (Ukraine). Inst. for Nuclear Reserch

    1995-05-01

    Aims of the present paper are: (i) presenting and analysing the results of various numerical calculations on the penetration and return times <{tau}{sub Pen}>, <{tau}{sub Ret}>, during tunnelling inside a rectangular potential barrier, for various penetration depths x{sub f}; (ii) putting forth and discussing suitable definitions, besides of the mean values, also of the variances (or dispersions) D{sub {tau}T} and D{sub {tau}R} for the time durations of transmission and reflection processes; (iii) mentioning, moreover, that our definition <{tau}{sub T}> for the average transmission time results to constitute an improvement of the ordinary dwell- time formula; (iv) commenting, at last, on the basis of the new numerical results, upon some recent criticism by C.R. Leavens. The paper stresses that numerical evaluations confirm that the approach implied, and implies, the existence of the Hartmann effect: an effect that in these days (due to the theoretical connections between tunnelling and evanescent-wave propagation) is receiving - at Cologne, Berkeley, Florence and Vienna - indirect, but quite interesting, experimental verification.

  1. Effect of defence response time during lunge in foil fencing.

    Science.gov (United States)

    Gutiérrez-Cruz, Carmen; Rojas, F Javier; Gutiérrez-Davila, Marcos

    2016-01-01

    The aim of this study was to analyse the effect of stimulus change timing on reaction response time parameters, horizontal velocity of the centre of mass (CM) and precision during offensive actions in fencing. Twelve fencers from the Spanish National Foil Team were included in the study. Two 500 Hz force plates were used to register the horizontal component of the reaction force while a 3D video camera set at 250 Hz recorded the spatial position of 11 body markers and a projector connected to a programmed stopwatch projected a moving target (stimulus) on a screen. When the circle (target) appeared in the centre of the plastron, fencers had to execute a step-forward-lunge as fast as possible, trying to touch the circle with the tip of the foil. During the lunge, the position of the target could randomly shift or not to three different positions. The stimulus change was performed randomly at four different times with a progressive delay. The results show that target changes did not have any effect when they occurred at the beginning of the movement sequence. However, when the target change was delayed, reaction and movement times increased and the technical execution of the lunge changed, leading to more errors.

  2. The effect of starspots on eclipse timings of binary stars

    CERN Document Server

    Watson, C A

    2004-01-01

    We investigate the effects that starspots have on the light curves of eclipsing binaries and in particular how they may affect the accurate measurement of eclipse timings. Concentrating on systems containing a low-mass main-sequence star and a white dwarf, we find that if starspots exhibit the Wilson depression they can alter the times of primary eclipse ingress and egress by several seconds for typical binary parameters and starspot depressions. In addition, we find that the effect on the eclipse ingress/egress times becomes more profound for lower orbital inclinations. We show how it is possible, in principle, to determine estimates of both the binary inclination and depth of the Wilson depression from light curve analysis The effect of depressed starspots on the O-C diagrams of eclipsing systems is also investigated. It is found that the presence of starspots will introduce a `jitter' in the O-C residuals and can cause spurious orbital period changes to be observed. Despite this, we show that the period ca...

  3. Real-time rendering of optical effects using spatial convolution

    Science.gov (United States)

    Rokita, Przemyslaw

    1998-03-01

    Simulation of special effects such as: defocus effect, depth-of-field effect, raindrops or water film falling on the windshield, may be very useful in visual simulators and in all computer graphics applications that need realistic images of outdoor scenery. Those effects are especially important in rendering poor visibility conditions in flight and driving simulators, but can also be applied, for example, in composing computer graphics and video sequences- -i.e. in Augmented Reality systems. This paper proposes a new approach to the rendering of those optical effects by iterative adaptive filtering using spatial convolution. The advantage of this solution is that the adaptive convolution can be done in real-time by existing hardware. Optical effects mentioned above can be introduced into the image computed using conventional camera model by applying to the intensity of each pixel the convolution filter having an appropriate point spread function. The algorithms described in this paper can be easily implemented int the visualization pipeline--the final effect may be obtained by iterative filtering using a single hardware convolution filter or with the pipeline composed of identical 3 X 3 filters placed as the stages of this pipeline. Another advantage of the proposed solution is that the extension based on proposed algorithm can be added to the existing rendering systems as a final stage of the visualization pipeline.

  4. Effect of multiple time-delay on vibrational resonance.

    Science.gov (United States)

    Jeevarathinam, C; Rajasekar, S; Sanjuán, M A F

    2013-03-01

    We report our investigation on the effect of multiple time-delay on vibrational resonance in a single Duffing oscillator and in a system of n Duffing oscillators coupled unidirectionally and driven by both a low- and a high-frequency periodic force. For the single oscillator, we obtain analytical expressions for the response amplitude Q and the amplitude g of the high-frequency force at which resonance occurs. The regions in parameter space of enhanced Q at resonance, as compared to the case in absence of time-delay, show a bands-like structure. For the two-coupled oscillators, we explain all the features of variation of Q with the control parameter g. For the system of n-coupled oscillators with a single time-delay coupling, the response amplitudes of the oscillators are shown to be independent of the time-delay. In the case of a multi time-delayed coupling, undamped signal propagation takes place for coupling strength (δ) above a certain critical value (denoted as δu). Moreover, the response amplitude approaches a limiting value QL with the oscillator number i. We obtain analytical expressions for both δu and QL.

  5. Effects of sugammadex on activated partial thromboplastin time and prothrombin time in healthy subjects.

    Science.gov (United States)

    De Kam, Pieter-Jan; Grobara, Peter; Prohn, Marita; Höppener, Floris; Kluft, Cornelis; Burggraaf, Jacobus; Langdon, Ronald B; Peeters, Pierre

    2014-03-01

    To assess the impact of sugammadex on activated partial thromboplastin time (APTT) and international normalized ratio for prothrombin time (PT(INR)) in healthy subjects and characterize the concentration-dependency of sugammadex effects on APTT and prothrombin time (PT) in normal human plasma in vitro. Eight healthy subjects (18 - 45 years of age) were administered intravenous doses of 4 mg/kg sugammadex, 16 mg/kg sugammadex, or placebo in a randomized, placebo-controlled, three period cross-over trial. The primary endpoint was area under the curve from 2 to 60 minutes post-dose (AUC2-60min) for APTT and PT(INR). In vitro, the effects of sugammadex on APTT and PT were assessed in pooled normal human citrate plasma. In subjects dosed with 4 and 16 mg/kg sugammadex, geometric mean ratios (treated vs. placebo) for AUC2-60min were 1.085 (95% confidence interval, 0.888 - 1.325) and 1.019 (0.868 - 1.195), respectively, for APTT, and 1.047 (0.904 - 1.213) and 1.096 (0.953 - 1.261), respectively, for PT(INR). At individual timepoints, mean APTT and PT(INR) increased by up to 22% after 16 mg/kg sugammadex compared with placebo. All such increases occurred within 30 minutes post-dose. Sugammadex was generally well tolerated. In the in vitro experiments, addition of sugammadex to plasma resulted in limited, concentration dependent increases in both APTT and PT. At 200 μg/mL (the mean maximum concentration reached therapeutically), the relative increases were 29% and 19%, respectively. Administration of sugammadex is associated with a dose-related, limited and transient prolongation of APTT and PT(INR) that is unlikely to be of clinical relevance.

  6. Anxiety Symptoms in African American Youth: The Role of Puberty and Biological Sex

    Science.gov (United States)

    Carter, Rona

    2015-01-01

    This study examined the effects of pubertal status, pubertal timing (actual and perceived), and youth biological sex on symptom dimensions of anxiety (i.e., social, separation, harm avoidance, physical) in African Americans (n = 252; ages 8-12). For girls, results indicated that pubertal status and timing (actual) exerted similar effects for some…

  7. Assessment of circulating sex steroid levels in prepubertal and pubertal boys and girls by a novel ultrasensitive gas chromatography-tandem mass spectrometry method

    DEFF Research Database (Denmark)

    Courant, Frédérique; Aksglæde, Lise; Antignac, Jean-Philippe

    2010-01-01

    Estrogens and androgens play key roles for pubertal onset and sexual maturation. Most currently used immunoassays are not sensitive enough to accurately measure the low circulating levels of sex steroids in children without any signs of puberty. However, this does not exclude that sex steroids have...... important biological roles in prepubertal children....

  8. Assessment of circulating sex steroid levels in prepubertal and pubertal boys and girls by a novel ultrasensitive gas chromatography-tandem mass spectrometry method

    DEFF Research Database (Denmark)

    Courant, Frédérique; Aksglæde, Lise; Antignac, Jean-Philippe;

    2010-01-01

    Estrogens and androgens play key roles for pubertal onset and sexual maturation. Most currently used immunoassays are not sensitive enough to accurately measure the low circulating levels of sex steroids in children without any signs of puberty. However, this does not exclude that sex steroids ha...

  9. Effectiveness of LANAP over time as measured by tooth loss.

    Science.gov (United States)

    Tilt, Lloyd V

    2012-01-01

    This study examines the effectiveness of the laser-assisted new attachment procedure (LANAP) as measured by tooth loss, comparing data to published studies using conventional surgical treatment modalities for the primary treatment of Types III and IV periodontitis. Retrospective data from 107 patients presenting with Types III and IV periodontitis were gathered and evaluated. All patients received LANAP periodontal therapy as their primary surgical treatment according to the FDA-cleared LANAP protocol. The patients averaged 6.2 years post-treatment. The data were compared to several published studies for outcome classification and tooth loss over time. The effectiveness of LANAP as a primary treatment method for Types III and IV periodontitis compares very favorably with conventional surgical treatment modalities concerning tooth loss and stability over time, need for surgical retreatment, and outcome classification. Dentistry continues to develop less invasive means of providing patient care without sacrificing results. Less invasive treatment of periodontitis, with reduced postoperative morbidity yet equal results in tooth retention over time is an important goal. LANAP treatment for moderate and advanced periodontitis provides a less invasive treatment alternative for the dentist and patient to consider as a part of informed consent.

  10. The effect of time headway feedback on following behaviour.

    Science.gov (United States)

    Fairclough, S H; May, A J; Carter, C

    1997-05-01

    A field study was conducted to assess the impact of continuous time headway feedback on following behaviour. An equipped vehicle was fitted with a microwave radar connected to a head-down display. The display was supplemented by an auditory tone which sounded if headway decreased below 1 second. Sixteen subjects participated in five consecutive sessions conducted on a U.K. motorway. The presence of the system and the time of the journey (i.e. rush hour vs off-peak) was manipulated across the experimental sessions. Results revealed that the presence of the system reduced the proportion of time the subjects spent at low headways (e.g. headways and (b) those scenarios characterised as following a lead vehicle at a constant velocity. The presence of the system increased time headway to a lead vehicle when an overtaking manoeuvre was initiated, but only in off-peak traffic. The system had no significant effect on speed-keeping behaviour or driver's mental workload.

  11. Genetics of primary and timing effects in the mnd mouse

    Energy Technology Data Exchange (ETDEWEB)

    Messer, A.; Plummer, J.; MacMillen, M.C. [New York State, Albany, NY (United States)] [and others

    1995-06-05

    The mnd mouse shows a spontaneous adult-onset hereditary neurological disease, with motor abnormality by 6 months of age, progressing to severe spastic paralysis and premature death. The disease is autosomal recessive, with heterozygote effects seen under stress. It maps to mouse chromosome (chr) 8. Histopathology with Nissl stains documents substantial abnormalities of upper and lower motor neurons, and there is retinal degeneration beginning in the first month, even without light exposure. Increasing levels of autofluorescent lipopigment are found in both neuronal and non-neuronal tissues as the mnd mice age. Recently, NCL-like inclusions and accumulating subunit c have also been described. When mnd is outcrossed to the AKR/J genetic background, ca. 40% of the mnd/mnd F2 progeny show early onset (onset by 4.5-5 months and death by 7 months). This accelerated timing effect seems to be strain-specific, and unlinked to the mnd gene itself. Our current working hypothesis is that the timing effect is due to 2 or 3 unlinked dominant genes with incomplete penetrance at any single locus. In a combined RFLP/PCR fragment genetic analysis, the strongest deviation from the expected ratio of AKR vs B6 alleles occurs with markers on proximal half of chr 1. Additional loci on chrs 5 and 10 may also be involved. The mechanism of interaction of these modifying genes with the primary mnd gene may offer new therapeutic avenues. 22 refs., 2 tabs.

  12. Financial time series analysis based on effective phase transfer entropy

    Science.gov (United States)

    Yang, Pengbo; Shang, Pengjian; Lin, Aijing

    2017-02-01

    Transfer entropy is a powerful technique which is able to quantify the impact of one dynamic system on another system. In this paper, we propose the effective phase transfer entropy method based on the transfer entropy method. We use simulated data to test the performance of this method, and the experimental results confirm that the proposed approach is capable of detecting the information transfer between the systems. We also explore the relationship between effective phase transfer entropy and some variables, such as data size, coupling strength and noise. The effective phase transfer entropy is positively correlated with the data size and the coupling strength. Even in the presence of a large amount of noise, it can detect the information transfer between systems, and it is very robust to noise. Moreover, this measure is indeed able to accurately estimate the information flow between systems compared with phase transfer entropy. In order to reflect the application of this method in practice, we apply this method to financial time series and gain new insight into the interactions between systems. It is demonstrated that the effective phase transfer entropy can be used to detect some economic fluctuations in the financial market. To summarize, the effective phase transfer entropy method is a very efficient tool to estimate the information flow between systems.

  13. Spectral characteristics of time resolved magnonic spin Seebeck effect

    Energy Technology Data Exchange (ETDEWEB)

    Etesami, S. R.; Chotorlishvili, L.; Berakdar, J. [Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle (Germany)

    2015-09-28

    Spin Seebeck effect (SSE) holds promise for new spintronic devices with low-energy consumption. The underlying physics, essential for a further progress, is yet to be fully clarified. This study of the time resolved longitudinal SSE in the magnetic insulator yttrium iron garnet concludes that a substantial contribution to the spin current stems from small wave-vector subthermal exchange magnons. Our finding is in line with the recent experiment by S. R. Boona and J. P. Heremans [Phys. Rev. B 90, 064421 (2014)]. Technically, the spin-current dynamics is treated based on the Landau-Lifshitz-Gilbert equation also including magnons back-action on thermal bath, while the formation of the time dependent thermal gradient is described self-consistently via the heat equation coupled to the magnetization dynamics.

  14. Spectral characteristics of time resolved magnonic spin Seebeck effect

    Science.gov (United States)

    Etesami, S. R.; Chotorlishvili, L.; Berakdar, J.

    2015-09-01

    Spin Seebeck effect (SSE) holds promise for new spintronic devices with low-energy consumption. The underlying physics, essential for a further progress, is yet to be fully clarified. This study of the time resolved longitudinal SSE in the magnetic insulator yttrium iron garnet concludes that a substantial contribution to the spin current stems from small wave-vector subthermal exchange magnons. Our finding is in line with the recent experiment by S. R. Boona and J. P. Heremans [Phys. Rev. B 90, 064421 (2014)]. Technically, the spin-current dynamics is treated based on the Landau-Lifshitz-Gilbert equation also including magnons back-action on thermal bath, while the formation of the time dependent thermal gradient is described self-consistently via the heat equation coupled to the magnetization dynamics.

  15. Relaxation time effects of wave ripples on tidal beaches

    Science.gov (United States)

    Austin, M. J.; Masselink, G.; O'Hare, T. J.; Russell, P. E.

    2007-08-01

    Seabed roughness due to wave ripples is a key factor in controlling sediment transport processes in the nearshore zone. Roughness is commonly considered a function of the ripple geometry, which in turn, can be predicted from sediment and hydrodynamic parameters. Existing ripple predictors consider the bed morphology to be in equilibrium with the hydrodynamics, whereas recent laboratory measurements show that the time scale for ripple development is of the order of tens of minutes to hours. Here we show that wave ripples on tidal beaches are significantly affected by relaxation time effects, with ripple height and length progressively increasing during the rising tide and remaining constant during the falling tide. Moreover, we examine the ripples in the context of existing empirical models and suggest how the temporal evolution over a tidal cycle may be predicted.

  16. Effectiveness and timing of vaccination during school measles outbreak.

    Science.gov (United States)

    Bonačić Marinović, Axel Antonio; Swaan, Corien; Wichmann, Ole; van Steenbergen, Jim; Kretzschmar, Mirjam

    2012-09-01

    Despite high vaccination coverage in most European countries, large community outbreaks of measles do occur, normally clustered around schools and resulting from suboptimal vaccination coverage. To determine whether or when it is worth implementing outbreak-response vaccination campaigns in schools, we used stochastic outbreak models to reproduce a public school outbreak in Germany, where no vaccination campaign was implemented. We assumed 2 scenarios covering the baseline vaccination ratio range (91.3%-94.3%) estimated for that school and computed outbreaks assuming various vaccination delays. In one scenario, reacting (i.e., implementing outbreak-response vaccination campaigns) within 12-24 days avoided large outbreaks and reacting within 50 days reduced outbreak size. In the other scenario, reacting within 6-14 days avoided large outbreaks and reacting within 40 days reduced the outbreak size. These are realistic time frames for implementing school outbreak response vaccination campaigns. High baseline vaccination ratios extended the time needed for effective response.

  17. The Effect of Spark Timing on the Spark Ignition

    Directory of Open Access Journals (Sweden)

    Rafeq A. Khalefa

    2013-04-01

    Full Text Available  In this work the effect of spark timing on the spark ignition engines is investigated by computer simulation and experimental test for speeds of (1500,2000,2500,3000 and 3500rpm at spark timing of (20o,30o,40o,50o and 60o before TDC for each speed. This is done in order to find a suitable  mathematical expression for spark ignition advancing with respect to the speed of the engine to predict the correct ignition advance  as in real engines .The results showed that the method of using a mathematical expression is more realistic and reasonable  comparing  with the results obtained by other workers. 

  18. The effect of mindfulness meditation on time perception.

    Science.gov (United States)

    Kramer, Robin S S; Weger, Ulrich W; Sharma, Dinkar

    2013-09-01

    Research has increasingly focussed on the benefits of meditation in everyday life and performance. Mindfulness in particular improves attention, working memory capacity, and reading comprehension. Given its emphasis on moment-to-moment awareness, we hypothesised that mindfulness meditation would alter time perception. Using a within-subjects design, participants carried out a temporal bisection task, where several probe durations are compared to "short" and "long" standards. Following this, participants either listened to an audiobook or a meditation that focussed on the movement of breath in the body. Finally, participants completed the temporal bisection task for a second time. The control group showed no change after the listening task. However, meditation led to a relative overestimation of durations. Within an internal clock framework, a change in attentional resources can produce longer perceived durations. This meditative effect has wider implications for the use of mindfulness as an everyday practice and a basis for clinical treatment.

  19. Effect of blanching temperature and dipping time on drying time of broccoli.

    Science.gov (United States)

    Doymaz, Ibrahim

    2014-03-01

    Drying characteristics of broccoli was experimentally studied in cabinet-type convective dryer. Experiments were conducted using constant air velocity of 2 m/s and air temperature of 60 . Drying rate increased with increasing blanching temperature and thus reduced the drying time. The experimental drying data were used to fit twelve drying models and drying rate constants and coefficients of the models were determined by non-linear regression analysis. Estimations by the Midilli et al. model were in good agreement with the experimental data obtained. Fick's second law was used to calculate the effective moisture diffusivity, which varied from 1.987 to 3.577 × 10(-8) m(2)/s for the given blanching temperature range. The rehydration ratio was observed to increase with increasing blanching temperature.

  20. Immunomodulating effect of blood transfusion: is storage time important?

    DEFF Research Database (Denmark)

    Mynster, T; Dybkjoer, E; Kronborg, Gitte

    1998-01-01

    to the stored blood, were used in a culture system with LPS and PHA as stimulators of TNF-alpha and IL-2 release. The effect of added supernatants, from either stored whole blood or SAGM blood, on cytokine release was evaluated compared to saline as control. TNF-alpha concentration was analyzed by ELISA after...... culture for 24 h and IL-2 after 72 h, respectively. RESULTS: Supernatants from both stored whole blood and SAGM blood showed a significant decrease in both LPS- and PHA-stimulated TNF-alpha release that was dependent on storage time. IL-2 was not detected in response to LPS stimulation. PHA-stimulated IL...

  1. Committed effective doses at various times after intakes of radionuclides

    CERN Document Server

    Phipps, A W; Kendall, G M; Silk, T J; Stather, J W

    1991-01-01

    This report contains details of committed effective doses at nine times after intake from intakes by ingestion and inhalation of 1 mu 1 AMAD particles by adults. Data are given for various chemical forms of 359 nuclides. It complements NRPB-R245 which describes the changes which have taken place since the last NRPB compendium of dose per unit intake factors (dose coefficients) and gives summary tables. Information on committed equivalent doses to organs is given in NRPB-M288. The information given in these memoranda is also available as a microcomputer package - NRPB-SR245.

  2. Developmental competence and embryo quality of small oocytes from pre-pubertal goats cultured in IVM medium supplemented with low level of hormones, insulin-transferrin-selenium and ascorbic acid.

    Science.gov (United States)

    Hammami, S; Morató, R; Romaguera, R; Roura, M; Catalá, M G; Paramio, M T; Mogas, T; Izquierdo, D

    2013-04-01

    The aim of this study was to test the effect of insulin-transferrin-selenium (ITS) and L-ascorbic acid (AA) supplementation and the hormonal level during in vitro maturation (IVM) of small oocytes from pre-pubertal goat on the blastocyst yield and quality. Concretely, we used four maturation media: conventional IVM medium (CM), growth medium (GM: CM+ITS+AA and low level of hormones), modified CM (mCM: CM with low level of hormones) and modified GM (mGM: CM+ITS+AA and normal level of hormones). Cumulus-oocyte complexes (COCs) were classified into two categories according to oocyte diameter: <125 μm and ≥ 125 μm. Large oocytes were matured 24 h in CM (Treatment A). Small oocytes were matured randomly in six experimental groups: Treatment B: 24 h in CM; Treatment C: 12 h in GM and 12 h in CM; Treatment D: 24 h in mGM; Treatment E: 12 h in mGM and 12 h in CM; Treatment F: 12 h in mCM and 12 h in CM; and Treatment G: 12 h in GM and 12 h in mGM. After IVM, oocytes were fertilized and cultured for 8 days. The blastocyst quality was assessed by the survival following vitrification/warming and the mean cell number. When different maturation media were combined, the blastocyst rate did not improve. The large oocytes produced the highest blastocysts yield. However, the culture of small oocytes in GM (53.3%) enhanced the post-warming survival of blastocysts compared to large oocytes matured in CM (35.7%). In conclusion, IVM of pre-pubertal goat small oocytes in GM would be useful to improve the quality of in vitro-produced blastocysts.

  3. Demographic translation and tempo effects: An accelerated failure time perspective

    Directory of Open Access Journals (Sweden)

    Germán Rodriguez

    2006-02-01

    Full Text Available In this paper I review the concept of tempo effects in demography, focusing on the tempo adjustments proposed by Bongaarts and Feeney and drawing on the work of Ryder and Zeng and Land. I show that the period-shift model that underlies the proposed adjustments can be motivated from an accelerated failure time cohort perspective. I propose alternative measures of tempo under changing fertility and mortality that share a synthetic cohort interpretation with the adjusted measure of quantum. I stress similarities between the results for fertility and mortality, particularly in terms of mean age of childbearing and mean age at death, but also note some important distinctions. I conclude that the fertility adjustments can help distinguish quantum and tempo effects, but argue that in the case of mortality the Bongaarts-Feeney measure of tempo-adjusted life expectancy differs from conventional estimates because it reflects past mortality.

  4. Prisms to travel in time: Investigation of time-space association through prismatic adaptation effect on mental time travel.

    Science.gov (United States)

    Anelli, Filomena; Ciaramelli, Elisa; Arzy, Shahar; Frassinetti, Francesca

    2016-11-01

    Accumulating evidence suggests that humans process time and space in similar veins. Humans represent time along a spatial continuum, and perception of temporal durations can be altered through manipulations of spatial attention by prismatic adaptation (PA). Here, we investigated whether PA-induced manipulations of spatial attention can also influence more conceptual aspects of time, such as humans' ability to travel mentally back and forward in time (mental time travel, MTT). Before and after leftward- and rightward-PA, participants projected themselves in the past, present or future time (i.e., self-projection), and, for each condition, determined whether a series of events were located in the past or the future with respect to that specific self-location in time (i.e., self-reference). The results demonstrated that leftward and rightward shifts of spatial attention facilitated recognition of past and future events, respectively. These findings suggest that spatial attention affects the temporal processing of the human self.

  5. Medidas orofaciais em nipobrasileiros após crescimento puberal Nipobrazilians orofacial measurements after pubertal growth

    Directory of Open Access Journals (Sweden)

    Tassiana Barbeiro Fragoso de Sá

    2013-01-01

    Full Text Available OBJETIVO: descrever medidas orofaciais em nipobrasileiros após crescimento puberal e verificar diferenças entre medidas de mulheres negras, brancas e nipobrasileiras. MÉTODO: a casuística foi composta de 90 sujeitos japoneses ou descendentes de japoneses, sem histórico de miscigenação, ambos os sexos, entre 20 e 50 anos, sem queixas ou atendimentos fonoaudiológicos atuais ou prévios em motricidade orofacial, sem tratamento ortodôntico atual e sem alteração cognitiva. As medidas avaliadas foram: lábio superior, lábio inferior, filtro, terço superior da face, terço médio da face, terço inferior da face, lados da face, abertura máxima de boca e abertura máxima de boca com a língua na papila. O instrumento utilizado foi o paquímetro eletrônico digital da marca Jomarca. Os dados foram comparados com os achados na literatura referentes às mulheres negras e brancas. RESULTADOS: os dados coletados mostraram homogeneidade entre as medidas; os valores para todas as medidas foram maiores nos homens, com relevância estatística positiva. As diferenças mais significantes entre as negras, brancas e nipobrasileiras foram: terço superior e filtro das nipobrasileiras menor do que de negras e brancas. Para o terço médio não houve diferença estatística significante. O lábio superior das nipobrasileiras é maior do que das brancas e o lábio inferior das nipobrasileiras menor do que das negras. Lados da face sem diferenças estatísticas. CONCLUSÃO: foi possível verificar que as médias das medidas foram sempre maiores nos homens, que houve relações significantes entre algumas medidas orofaciais e que houve diferença estatisticamente significante entre as estruturas das brancas, negras e nipobrasileiras.PURPOSE: to describe orofacial measurements in nipobrazilians individuals after pubertal growth and to verify the differences among black, white and nipobrazilians women measures. METHOD: the sample was composed by 90 Asian

  6. Medidas orofaciais em nipobrasileiros após crescimento puberal Nipobrazilians orofacial measurements after pubertal growth

    Directory of Open Access Journals (Sweden)

    Tassiana Barbeiro Fragoso de Sá

    2013-04-01

    Full Text Available OBJETIVO: descrever medidas orofaciais em nipobrasileiros após crescimento puberal e verificar diferenças entre medidas de mulheres negras, brancas e nipobrasileiras. MÉTODO: a casuística foi composta de 90 sujeitos japoneses ou descendentes de japoneses, sem histórico de miscigenação, ambos os sexos, entre 20 e 50 anos, sem queixas ou atendimentos fonoaudiológicos atuais ou prévios em motricidade orofacial, sem tratamento ortodôntico atual e sem alteração cognitiva. As medidas avaliadas foram: lábio superior, lábio inferior, filtro, terço superior da face, terço médio da face, terço inferior da face, lados da face, abertura máxima de boca e abertura máxima de boca com a língua na papila. O instrumento utilizado foi o paquímetro eletrônico digital da marca Jomarca. Os dados foram comparados com os achados na literatura referentes às mulheres negras e brancas. RESULTADOS: os dados coletados mostraram homogeneidade entre as medidas; os valores para todas as medidas foram maiores nos homens, com relevância estatística positiva. As diferenças mais significantes entre as negras, brancas e nipobrasileiras foram: terço superior e filtro das nipobrasileiras menor do que de negras e brancas. Para o terço médio não houve diferença estatística significante. O lábio superior das nipobrasileiras é maior do que das brancas e o lábio inferior das nipobrasileiras menor do que das negras. Lados da face sem diferenças estatísticas. CONCLUSÃO: foi possível verificar que as médias das medidas foram sempre maiores nos homens, que houve relações significantes entre algumas medidas orofaciais e que houve diferença estatisticamente significante entre as estruturas das brancas, negras e nipobrasileiras.PURPOSE: to describe orofacial measurements in nipobrazilians individuals after pubertal growth and to verify the differences among black, white and nipobrazilians women measures. METHOD: the sample was composed by 90 Asian

  7. The effect of nonprobative photographs on truthiness persists over time.

    Science.gov (United States)

    Fenn, Elise; Newman, Eryn J; Pezdek, Kathy; Garry, Maryanne

    2013-09-01

    When making rapid judgments about the truth of a claim, related nonprobative information leads people to believe the claim-an effect called "truthiness" (Newman, Garry, Bernstein, Kantner, & Lindsay, 2012). For instance, within a matter of seconds, subjects judge the claim "The Mona Lisa has no eyebrows," to be true more often when it appears with a photograph of the Mona Lisa viewed at a distance by a person. But does truthiness persist longer than a few seconds? To determine if truthiness "sticks," we asked people to judge if each trivia claim in a series was true. Half of the claims appeared with nonprobative photos; the rest appeared alone. In a second session 48h later, people returned and made the same judgments about the same statements, but this time, all claims appeared without photos. We found that truthiness "stuck." The magnitude of the effect of photos on subjective feelings of truth was consistent over time. These results fit with those from cognitive and educational psychology, as well as with the related idea that photos make relevant information more available and familiar-and therefore feel more true-even after a delay. © 2013. Published by Elsevier B.V. All rights reserved.

  8. Effective rotational correlation times of proteins from NMR relaxation interference

    Science.gov (United States)

    Lee, Donghan; Hilty, Christian; Wider, Gerhard; Wüthrich, Kurt

    2006-01-01

    Knowledge of the effective rotational correlation times, τc, for the modulation of anisotropic spin-spin interactions in macromolecules subject to Brownian motion in solution is of key interest for the practice of NMR spectroscopy in structural biology. The value of τc enables an estimate of the NMR spin relaxation rates, and indicates possible aggregation of the macromolecular species. This paper reports a novel NMR pulse scheme, [ 15N, 1H]-TRACT, which is based on transverse relaxation-optimized spectroscopy and permits to determine τc for 15N- 1H bonds without interference from dipole-dipole coupling of the amide proton with remote protons. [ 15N, 1H]-TRACT is highly efficient since only a series of one-dimensional NMR spectra need to be recorded. Its use is suggested for a quick estimate of the rotational correlation time, to monitor sample quality and to determine optimal parameters for complex multidimensional NMR experiments. Practical applications are illustrated with the 110 kDa 7,8-dihydroneopterin aldolase from Staphylococcus aureus, the uniformly 15N-labeled Escherichia coli outer membrane protein X (OmpX) in 60 kDa mixed OmpX/DHPC micelles with approximately 90 molecules of unlabeled 1,2-dihexanoyl- sn-glycero-3-phosphocholine (DHPC), and the 16 kDa pheromone-binding protein from Bombyx mori, which cover a wide range of correlation times.

  9. Effects of yeast, fermentation time, and preservation methods on tarhana.

    Science.gov (United States)

    Gurbuz, Ozan; Gocmen, Duygu; Ozmen, Nese; Dagdelen, Fatih

    2010-01-01

    The physicochemical properties of tarhana soup produced with different dough treatments, fermentation times, and preservation methods were examined. Tarhana doughs were prepared with yogurt (control) or baker's yeast (Saccharomyces cerevisiae) and fermented for 3 days. Samples were taken at 24, 48, and 72 hr. Samples were then preserved via one of four methods: sun dried, dried in the shade, vacumn dried, and frozen. Frozen samples produced lower organic acid levels after 72 hr of fermentation in both control (0.68 g/100 g) and yeast (0.61 g/100 g) applications than samples that were dried (0.94 g/100 g control samples; 0.81 g/100 g samples with yeast). Increasing fermentation time resulted in a significant effect on the formation of organic acid in the tarhana (p .01). However, sensory scores for tarhana prepared from the samples dried in a sheltered area showed a reduction in color desireablilty as the fermentation time increased. The soup prepared from frozen tarhana (72 hr fermentation, with yeast) had the highest scores with respect to color, mouth feel, flavor, and overall acceptability. Vacuum-dried samples' scores in these areas were also high in comparison to the two other drying methods.

  10. Effect of shift working on reaction time in hospital employees.

    Science.gov (United States)

    Namita; Ranjan, Din Prakash; Shenvi, Dhangauri N

    2010-01-01

    Visual and Auditory reaction time (VRT, ART) were studied in 286 hospital employees during day duty and night duty in the age group of 20 to 60 years to find out the effect of shift working on reaction time in hospital employees. Subjects were presented with two visual stimuli i.e. red and green light and two auditory stimuli, i.e., high pitch and low pitch sound stimuli. The significance of difference of VRT and ART during day duty and night duty was studied with the use of standard error of difference between two means. The statistical difference was determined by 'z' test. VRT during day duty (231.60 +/- 30.93) were less than VRT during night duty (234.98 +/- 32.27) and ART during day duty (224.69 +/- 46.95) were also less than ART during night duty (228.74 +/- 47.01). Our results indicate that reaction time is more during night duty as compared to day duty but the difference is not significant. It may be because of hospital employees get adapted to reduced sleep after working continuously in the shift system.

  11. Removing atmosphere loading effect from GPS time series

    Science.gov (United States)

    Tiampo, K. F.; Samadi Alinia, H.; Samsonov, S. V.; Gonzalez, P. J.

    2015-12-01

    The GPS time series of site position are contaminated by various sources of noise; in particular, the ionospheric and tropospheric path delays are significant [Gray et al., 2000; Meyer et al., 2006]. The GPS path delay in the ionosphere is largely dependent on the wave frequency whereas the delay in troposphere is dependent on the length of the travel path and therefore site elevation. Various approaches available for compensating ionosphere path delay cannot be used for removal of the tropospheric component. Quantifying the tropospheric delay plays an important role for determination of the vertical GPS component precision, as tropospheric parameters over a large distance have very little correlation with each other. Several methods have been proposed for tropospheric signal elimination from GPS vertical time series. Here we utilize surface temperature fluctuations and seasonal variations in water vapour and air pressure data for various spatial and temporal profiles in order to more accurately remove the atmospheric path delay [Samsonov et al., 2014]. In this paper, we model the atmospheric path delay of vertical position time series by analyzing the signal in the frequency domain and study its dependency on topography in eastern Ontario for the time period from January 2008 to December 2012. Systematic dependency of amplitude of atmospheric path delay as a function of height and its temporal variations based on the development of a new, physics-based model relating tropospheric/atmospheric effects with topography and can help in determining the most accurate GPS position.The GPS time series of site position are contaminated by various sources of noise; in particular, the ionospheric and tropospheric path delays are significant [Gray et al., 2000; Meyer et al., 2006]. The GPS path delay in the ionosphere is largely dependent on the wave frequency whereas the delay in troposphere is dependent on the length of the travel path and therefore site elevation. Various

  12. The use of focus groups to examine pubertal concerns in preteen girls: initial findings and implications for practice and research.

    Science.gov (United States)

    Doswell, W M; Vandestienne, G

    1996-01-01

    This article presents the findings of four focus groups aimed at discovering the concerns a group of 9- to 12-year-old African American and Hispanic girls (N = 38) had about puberty, the transition to adolescence, and growing up. Among the factors these girls liked about growing up were increasing independence from parents, widening social relations with same- and opposite-sex friends, and an increase in decision making regarding clothes and activities. What they reported as not liking about growing up were an increase in peer pressure, high parental expectations, and more responsibility for their actions in home, school, and recreational activities. Health care for this group must include systematic monitoring of pubertal development and concerns in order to aggressively educate preadolescents to negotiate this period smoothly and to avoid high-risk behaviors that could have negative health and social sequelae during adolescence and adulthood.

  13. Sex steroids and brain structure in pubertal boys and girls: a mini-review of neuroimaging studies.

    Science.gov (United States)

    Peper, J S; Hulshoff Pol, H E; Crone, E A; van Honk, J

    2011-09-15

    Puberty is an important period during development hallmarked by increases in sex steroid levels. Human neuroimaging studies have consistently reported that in typically developing pubertal children, cortical and subcortical gray matter is decreasing, whereas white matter increases well into adulthood. From animal studies it has become clear that sex steroids are capable of influencing brain organization, both during the prenatal period as well as during other periods characterized by massive sex steroid changes such as puberty. Here we review structural neuroimaging studies and show that the changes in sex steroids availability during puberty and adolescence might trigger a period of structural reorganization of grey and white matter in the developing human brain. This article is part of a Special Issue entitled: Neuroactive Steroids: Focus on Human Brain.

  14. A one-year exercise intervention program in pre-pubertal girls does not influence hip structure

    Directory of Open Access Journals (Sweden)

    Ahlborg Henrik G

    2008-01-01

    Full Text Available Abstract Background We have previously reported that a one-year school-based exercise intervention program influences the accrual of bone mineral in pre-pubertal girls. This report aims to evaluate if also hip structure is affected, as geometry independent of bone mineral influences fracture risk. Methods Fifty-three girls aged 7 – 9 years were included in a curriculum-based exercise intervention program comprising 40 minutes of general physical activity per school day (200 minutes/week. Fifty healthy age-matched girls who participated in the general Swedish physical education curriculum (60 minutes/week served as controls. The hip was scanned by dual X-ray absorptiometry (DXA and the hip structural analysis (HSA software was applied to evaluate bone mineral content (BMC, areal bone mineral density (aBMD, periosteal and endosteal diameter, cortical thickness, cross-sectional moment of inertia (CSMI, section modulus (Z and cross-sectional area (CSA of the femoral neck (FN. Annual changes were compared. Group comparisons were done by independent student's t-test between means and analyses of covariance (ANCOVA. Pearson's correlation test was used to evaluate associations between activity level and annual changes in FN. All children remained at Tanner stage 1 throughout the study. Results No between-group differences were found during the 12 months study period for changes in the FN variables. The total duration of exercise during the year was not correlated with the changes in the FN traits. Conclusion Evaluated by the DXA technique and the HSA software, a general one-year school-based exercise program for 7–9-year-old pre-pubertal girls seems not to influence the structure of the hip.

  15. The cumulative energy effect for improved ignition timing

    Energy Technology Data Exchange (ETDEWEB)

    Markhotok, A., E-mail: amarhotk@phys.washington.edu [Physics Department, Old Dominion University, Norfolk, Virginia 23529 (United States)

    2015-04-15

    A technique capable of improving timing in ignition applications is proposed. It is based on the use of shock waves propagating in a specific medium that allows achieving extremely high speeds and energies. The model uses the energy cumulation effect in the presence of the shock wave refraction on an interface with plasma. The problem was solved analytically and the effects were demonstrated for a cylindrically symmetrical geometry. Numerical results show very quick and uneven acceleration of different portions of the shock front. Its strong distortions lead to formation of a sharply focused jet near the axis of symmetry. The ability of the shock to achieve extremely high speeds and energies can be useful in design of efficient combustors for hypersonic systems, and possibly offers an alternative way of construction of a nuclear fusion reactor. Recommendations are given in terms of adjustment parameters and can be applied at any problem scale and for various combinations of the strengths of the effects involved in the problem.

  16. Risking it for love: romantic relationships and early pubertal development confer risk for later disruptive behavior disorders in African-American girls receiving psychiatric care.

    Science.gov (United States)

    Javdani, Shabnam; Rodriguez, Erin M; Nichols, Sara R; Emerson, Erin; Donenberg, Geri R

    2014-11-01

    Disruptive behavior problems (DBP) represent a growing concern for young women (e.g., Snyder and Sickmund, 2006), but gender-specific investigations have been traditionally underrepresented in this area. The purpose of this study is to examine the associations among gender-relevant risk factors for DBP among 217 African American girls in psychiatric care. African American girls, 12-16 years old (M = 14.6; SD = 1.2), and their primary female caregivers (N = 254) were recruited from outpatient mental health clinics and reported on girls' DBP, heterosexual dating experiences (romantic and sexual), peer relationships, pubertal development, and self-silencing at baseline, 6-, and 12 months. Structural Equation Modeling examined evidence for full versus mediated (via self-silencing) models and the structural relationships (direct and indirect) among key study variables. Results suggest that the full model was a significantly better fit than the mediated model as indicated by a Chi-squared difference test (p romantic dating experiences and lower quality peer relationships at baseline predicted DBP at 12 months. Sexual dating experiences were more strongly linked with DBP at 12 months for early maturing compared to average or later maturing girls. Indirect effects analyses suggested that girls' suppression of relational needs, assessed through a measure of self-silencing, explained the association between peer relationships and DBP. Findings highlight the importance of the relational context for girls' DBP, with treatment implications supporting relationship-based models of care, early intervention, and skill building around negotiating needs with peers and partners.

  17. [Evaluation of nutrition mode and nutritional status and pro health education of children during the period of pubertal spurt in the city of Szczecin].

    Science.gov (United States)

    Goluch-Koniuszy, Zuzanna; Friedrich, Mariola; Radziszewska, Magdalena

    2009-01-01

    This research was aimed at evaluation of the method of nutrition and the state of nutrition in the children aged 13 during the period of pubertal spurt who had their body mass, body height and waist measurement defined. These values led to calculation of BMI, WC, and WHtR indicators, which were related to centile distribution of children from Warszawa and Lódź. Only in 63.6% of girls and 68.9% of boys from Szczecin schools the value of BMI was proper. The problem of accumulation of fat tissue (WC > or = 90 c) around the waist refers to nearly 14% of girls and 9.4% of boys. The value of the indicator WHtR > or = 90 c was found in 11% of the children under research. Children with overweight (BMI 90-97 c) and obesity (BMI > or = 97 c) were selected based on the value of BMI indicator. Their menus of three chosen at random weekdays were obtained. Analysis of the nutrition method of children with overweight and obesity showed low energy value of the diet, general protein, complex carbohydrates, cellulose, mineral components (Ca, Mg, Fe, Cu, Zn), A, E (girls), C (boys), group B vitamins and also liquids deficiency. The children have undergone a special pro health education in the form of "live" workshops and 3 months after an evaluation inquiry was conducted to assess the effects of the workshops. The analysis of the evaluation inquiry showed that the children have included in their diet breakfasts and afternoon snacks and to their main meal menus whole wheat products, larger quantity of vegetables, fruit and water. It has been also established that sweets, meals of fast food types, chips, pizzy and energizing drinks have been limited.

  18. "Deflategate": Time, Temperature, and Moisture Effects on Football Pressure

    Science.gov (United States)

    Blumenthal, Jack; Beljak, Lauren; Macatangay, Dahlia-Marie; Helmuth-Malone, Lilly; McWilliams, Catharina; Raptis, Sofia

    2016-09-01

    In a recent paper in TPT, DiLisi and Rarick used the National Football League "Deflategate" controversy to introduce to physics students the physics of a bouncing ball. In this paper, we measure and analyze the environmental effects of time, ambient temperature, and moisture on the internal pressure of an NFL football. We focus on the rate of pressure recovery that occurs when a cold football (either wet or dry) is returned to the warm locker room environment where the pressure was initially measured. Both studies stem from the so-called NFL "Deflategate" controversy in which footballs that initially met a minimum internal pressure requirement were rechecked at halftime of the AFC Championship game, and in some cases were reported to have fallen below the minimum pressure requirement. The question is whether the pressure changes were due to environmental exposure or rather to some air being released from the balls, or both.

  19. Dynamic Leidenfrost effect: relevant time- and length-scales

    CERN Document Server

    Shirota, Minori; Sun, Chao; Prosperetti, Andrea; Lohse, Detlef

    2015-01-01

    When a liquid droplet impacts a hot solid surface, enough vapor may be generated under it as to prevent its contact with the solid. The minimum solid temperature for this so-called Leidenfrost effect to occur is termed the Leidenfrost temperature, or the dynamic Leidenfrost temperature when the droplet velocity is non-negligible. We observe the wetting/drying and the levitation dynamics of the droplet impacting on an (isothermal) smooth sapphire surface using high speed total internal reflection imaging, which enables us to observe the droplet base up to about 100 nm above the substrate surface. By this method we are able to reveal the processes responsible for the transitional regime between the fully wetting and the fully levitated droplet as the solid temperature increases, thus shedding light on the characteristic time- and length-scales setting the dynamic Leidenfrost temperature for droplet impact on an isothermal substrate.

  20. Experimental demonstration of the time reversal Aharonov-Casher effect.

    Science.gov (United States)

    Bergsten, Tobias; Kobayashi, Toshiyuki; Sekine, Yoshiaki; Nitta, Junsaku

    2006-11-10

    We demonstrate the time reversal Aharonov-Casher (AC) effect in small arrays of mesoscopic semiconductor rings. By using an electrostatic gate we can control the spin precession rate and follow the AC phase over several interference periods. We show that we control the precession rate in two different gate voltage ranges; in the lower range the gate voltage dependence is strong and linear and in the higher range the dependence in almost an order of magnitude weaker. We also see the second harmonic of the AC interference, oscillating with half the period. We finally map the AC phase to the spin-orbit interaction parameter alpha and find it is consistent with Shubnikov-de Haas analysis.

  1. Nonselective and polarization effects in time-resolved optogalvanic spectroscopy

    Science.gov (United States)

    Zhechev, D.; Steflekova, V.

    2016-02-01

    Three interfering effects in optogalvanic (OG) spectroscopy are identified in a hollow cathode discharge (HCD) - OG detector. The laser beam is found to generate two nonselective processes, namely photoelectron emission (PE) from the cathode surface with a sub-breakdown bias applied, and nonresonant space ionization. The convolution of these galvanic contributions was determined experimentally as an instrumental function and a deconvolution procedure to determine the actual OG signal was developed. Specific plasma conductance is detected dependent on the polarization of the laser beam irradiating. Linearly/circularly polarized light beam is found to induce OG signals differ in amplitude (and their shape parameters in the time-resolved OG signals (TROGS)). The phenomena coherence and specific conductance are found to be in causal relationship. The additional conductance due to coherent states of atoms manifests itself as an intrinsic instrumental property of OG detector.

  2. Effects of psychot herapy on REM latency and REM time.

    Science.gov (United States)

    Karle, W; Hopper, M; Switzer, A; Corriere, R; Woldenberg, L

    1980-08-01

    This study investigated the effect of a functional psychotherapy on the sleep EEG patterns of 6 patients. Contrary to original expectations no significant group differences in REM time and REM latency were found between two nights following therapy sessions and two normal nights. However, across the 4 nights the patients exhibited an average REM latency of 71 min. which was significantly shorter than that recorded in an independent study with the same design and a similar subject population. Clausen, Sersen, and Lidsky (1974) reported an average REM latency of 107.3 min. for 10 normal subjects also recorded across four nights. This result is compared with those in several other studies and discussed in relation to possible changes in dream patterns.

  3. Time-series intervention analysis of pedestrian countdown timer effects.

    Science.gov (United States)

    Huitema, Bradley E; Van Houten, Ron; Manal, Hana

    2014-11-01

    Pedestrians account for 40-50% of traffic fatalities in large cities. Several previous studies based on relatively small samples have concluded that Pedestrian Countdown Timers (PCT) may reduce pedestrian crashes at signalized intersections, but other studies report no reduction. The purposes of the present article are to (1) describe a new methodology to evaluate the effectiveness of introducing PCT signals and (2) to present results of applying this methodology to pedestrian crash data collected in a large study carried out in Detroit, Michigan. The study design incorporated within-unit as well as between-unit components. The main focus was on dynamic effects that occurred within the PCT unit of 362 treated sites during the 120 months of the study. An interrupted time-series analysis was developed to evaluate whether change in crash frequency depended upon of the degree to which the countdown timers penetrated the treatment unit. The between-unit component involved comparisons between the treatment unit and a control unit. The overall conclusion is that the introduction of PCT signals in Detroit reduced pedestrian crashes to approximately one-third of the preintervention level. The evidence for this reductionis strong and the change over time was shown to be a function of the extent to which the timers were introduced during the intervention period. There was no general drop-off in crash frequency throughout the baseline interval of over five years; only when the PCT signals were introduced in large numbers was consistent and convincing crash reduction observed. Correspondingly, there was little evidence of change in the control unit. Copyright © 2014. Published by Elsevier Ltd.

  4. Online psychophysics: reaction time effects in cognitive experiments.

    Science.gov (United States)

    Semmelmann, Kilian; Weigelt, Sarah

    2016-08-05

    Using the Internet to acquire behavioral data is currently on the rise. However, very basic questions regarding the feasibility of online psychophysics are still open. Here, we aimed to replicate five well-known paradigms in experimental psychology (Stroop, Flanker, visual search, masked priming, attentional blink) in three settings (classical "lab", "web-in-lab", "web") to account for possible changes in technology and environment. Lab and web-in-lab data were both acquired in an in-lab setting with lab using "Gold Standard" methods, while web-in-lab used web technology. This allowed for a direct comparison of potential differences in acquisition software. To account for additional environmental differences, the web technology experiments were published online to participate from home (setting web), thereby keeping the software and experimental design identical and only changing the environmental setting. Our main results are: First, we found an expected fixed additive timing offset when using web technology (M = 37 ms, SD = 8.14) and recording online (M = 87 ms, SD = 16.04) in comparison to lab data. Second, all task-specific effects were reproduced except for the priming paradigm, which couldn't be replicated in any setting. Third, there were no differences in error rates, which are independent of the timing offset. This finding further supports the assumption of data equality over all settings. Fourth, we found that browser type might be influencing absolute reaction times. Together, these results contribute to the slowly but steadily growing literature that online psychophysics is a suitable complement - or even substitute - to lab data acquisition.

  5. Tamping effects and confinement time in NIF experiments

    Science.gov (United States)

    Wang, Y. M.; Cheng, B.; Kwan, T. J. T.; Merrill, F.; Cerjan, C.; Batha, S. H.

    2015-11-01

    Tamper is expected to play an important role in inertial confinement fusion capsule experiments performed at the National Ignition Facility (NIF). It is expected to increase the confinement time of thermonuclear burning (TN) in the hot spot. In this work, we study the dependence of the capsule performance with respect to the density ratio of the pusher to the hot fuel at the cold-hot interface numerically through LASNEX simulations in one-dimension. Our study shows that the dependence of the capsule performance (neutron yield) with respect to the square root of the density ratio is not linear: the sharper the interface, the higher the tamping effect and neutron yields. Our analysis indicates that the tamping factor in both NIC and NIF experiments has not been appreciable and the tamping factor on yield is less than 1.1. Thus, the tamping factor has not yet played a significant role in the current NIF ignition design. Furthermore, the confinement time in NIF experiments will be discussed. (LA-UR-15-25596).

  6. Time-dependent effect in green synthesis of silver nanoparticles

    Directory of Open Access Journals (Sweden)

    Darroudi M

    2011-04-01

    Full Text Available Majid Darroudi1,2, Mansor Bin Ahmad3, Reza Zamiri4, AK Zak5, Abdul Halim Abdullah1,3, Nor Azowa Ibrahim31Advanced Materials and Nanotechnology Laboratory, Institute of Advanced Technology (ITMA, Universiti Putra Malaysia, Selangor, Malaysia; 2Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran; 3Department of Chemistry, 4Department of Physics, Faculty of Science, Universiti Putra Malaysia, Selangor, Malaysia; 5Low Dimensional Materials Research Center, Department of Physics, Faculty of Science, University of Malaya, Kuala Lumpur, MalaysiaAbstract: The application of “green” chemistry rules to nanoscience and nanotechnology is very important in the preparation of various nanomaterials. In this work, we successfully developed an eco-friendly chemistry method for preparing silver nanoparticles (Ag-NPs in natural polymeric media. The colloidal Ag-NPs were synthesized in an aqueous solution using silver nitrate, gelatin, and glucose as a silver precursor, stabilizer, and reducing agent, respectively. The properties of synthesized colloidal Ag-NPs were studied at different reaction times. The ultraviolet-visible (UV-vis spectra were in excellent agreement with the obtained nanostructure studies performed by transmission electron microscopy (TEM and their size distributions. The prepared samples were also characterized by X-ray diffraction (XRD and atomic force microscopy (AFM. The use of eco-friendly reagents, such as gelatin and glucose, provides green and economic attributes to this work.Keywords: silver nanoparticles, gelatin, green chemistry, time-dependent effect, ultraviolet-visible spectra

  7. Time Overrun and Cost Effectiveness in the Construction Industry

    Directory of Open Access Journals (Sweden)

    T.Subramani

    2014-06-01

    Full Text Available The project management technique of planning and scheduling using tools and devices are helpful in comparing the project with stipulated cost, time and quality. Resource tracking, Minimize the uncertainty and Cost Effectiveness is focused in this project. The software tool used for planning and scheduling is Primavera project planner enterprise for construction. The study covers three case studies of the process of planning, scheduling the activities and monitoring. A general re sequencing model had been proposed to overcome the delay factor from the critical area, to minimize the delay of the construction and to reduce the time, cost and it also helpful to concentrate on the major areas in the project. Re sequencing model leads the management to cost savings and make entire project success. Resource planning is one aspect, which decides the systematic execution of the project at worksite. This study is to have hands- on experience in an ongoing project, and evaluation of schedule of equipment, staff, Labor and Materials. It helps to plan and evaluate the resources for the Construction of the building project. This study also compares the cost variation due to the delay of the project and re scheduling the project by crashing process. KEYWORDS:

  8. Female reproductive disorders: the roles of endocrine-disrupting compounds and developmental timing

    DEFF Research Database (Denmark)

    Crain, D.A.; Janssen, S.J.; Edwards, T.M.

    2008-01-01

    , and pregnancy loss), breast (breast cancer, reduced duration of lactation), and pubertal timing were identified, reviewed, and summarized at a workshop. CONCLUSION(S): The data reviewed illustrate that EDCs contribute to numerous human female reproductive disorders and emphasize the sensitivity of early life...

  9. Designing time-limited cyber promotions: effects of time limit and involvement.

    Science.gov (United States)

    Teng, Ching-I; Huang, Li-Shia

    2007-02-01

    This study found that a longer time limit in cyber promotions results in lower time pressure perceptions by consumers and a greater rate of consumers choosing higher-priced items. Furthermore, products with which consumers are more involved entail higher time pressure, lower consumer satisfaction, and a lower share of consumers using the promotion for that product.

  10. Verbal fluency: Effect of time on item generation

    Directory of Open Access Journals (Sweden)

    Mayra Jacuviske Venegas

    Full Text Available Abstract The distribution of item generation/time in the performance of elderly on verbal fluency (VF remains unknown. Objective: To analyze the number of items, their distribution and impact of the first quartile on the final test result. Methods: 31 individuals performed the tests (average age=74 years; schooling=8.16 years. Results: The number of items produced in the first quartile differed from the other quartiles for both semantic and phonologic VF where 40% of items were produced in the first quartile. No effect of age was found and schooling influenced performance on the first and second quartiles of semantic VF and on the 1st, 2nd and 3rd quartiles of phonemic VF. Discussion: This study contributes with the finding that asymptotic levels are attained prior to the 30 seconds observed in other studies, being reached at the 15-second mark. Furthermore, schooling was found to be associated to the number of items produced in both the first and 2nd quartiles for semantic VF, and in 1st, 2nd and 3rd quartiles for phonemic fluency. Conclusion: The schooling effect was noted both in semantic and executive aspects of VF. The brief form of the VF test may represent a promising tool for clinical evaluation.

  11. Elastodynamic metasurface: Depolarization of mechanical waves and time effects

    Energy Technology Data Exchange (ETDEWEB)

    Boutin, Claude, E-mail: claude.boutin@entpe.fr [Ecole Nationale des Travaux Publics de l' Etat, Université de Lyon, LGCB, UMR CNRS 5513, Vaulx-en-Velin (France); Schwan, Logan [Acoustics Research Center, University of Salford, Newton Building, Salford M5 4WT (United Kingdom); Dietz, Matthew S. [Department of Civil Engineering, University of Bristol, Queen' s Building, Bristol BS8 1TR (United Kingdom)

    2015-02-14

    We report the concept of microstructured surfaces with inner resonance in the field of elastodynamics, so-called elastodynamic metasurfaces. Such metasurfaces allow for wavefield manipulation of mechanical waves by tuning the boundary conditions at specific frequencies. In particular, they can be used to depolarize elastic waves without introducing heterogeneities in the medium itself; the physical means to do so in homogeneous elastic media used to remain, surprisingly, an open question while depolarization is commonplace in electromagnetism. The principle relies on the anisotropic behaviour of a subwavelength array of resonators: Their subwavelength configuration confines the Bragg interferences scattered by resonators into a boundary layer. The effective behaviour of the resonating array is expressed with homogenization as an unconventional impedance, the frequency-dependence, and anisotropy of which lead to depolarization and time effects. The concept of the elastodynamic metasurface is tested experimentally and results bear testament to its efficacy and robustness. Elastodynamic metasurfaces are easily realized and analytically predictable, opening new possibilities in tomography techniques, ultrasonics, geophysics, vibration control, materials and structure design.

  12. Fast-Response-Time Shape-Memory-Effect Foam Actuators

    Science.gov (United States)

    Jardine, Peter

    2010-01-01

    Bulk shape memory alloys, such as Nitinol or CuAlZn, display strong recovery forces undergoing a phase transformation after being strained in their martensitic state. These recovery forces are used for actuation. As the phase transformation is thermally driven, the response time of the actuation can be slow, as the heat must be passively inserted or removed from the alloy. Shape memory alloy TiNi torque tubes have been investigated for at least 20 years and have demonstrated high actuation forces [3,000 in.-lb (approximately equal to 340 N-m) torques] and are very lightweight. However, they are not easy to attach to existing structures. Adhesives will fail in shear at low-torque loads and the TiNi is not weldable, so that mechanical crimp fits have been generally used. These are not reliable, especially in vibratory environments. The TiNi is also slow to heat up, as it can only be heated indirectly using heater and cooling must be done passively. This has restricted their use to on-off actuators where cycle times of approximately one minute is acceptable. Self-propagating high-temperature synthesis (SHS) has been used in the past to make porous TiNi metal foams. Shape Change Technologies has been able to train SHS derived TiNi to exhibit the shape memory effect. As it is an open-celled material, fast response times were observed when the material was heated using hot and cold fluids. A methodology was developed to make the open-celled porous TiNi foams as a tube with integrated hexagonal ends, which then becomes a torsional actuator with fast response times. Under processing developed independently, researchers were able to verify torques of 84 in.-lb (approximately equal to 9.5 Nm) using an actuator weighing 1.3 oz (approximately equal to 37 g) with very fast (less than 1/16th of a second) initial response times when hot and cold fluids were used to facilitate heat transfer. Integrated structural connections were added as part of the net shape process, eliminating

  13. The Welfare Effects of Involuntary Part-time Work

    DEFF Research Database (Denmark)

    Borowczyk-Martins, Daniel; Lalé, Etienne

    2017-01-01

    Employed individuals in the USA are increasingly more likely to move to involuntarily part-time work than to unemployment. Spells of involuntary part-time work are different from unemployment spells: a full-time worker who takes on a part-time job suffers an earnings loss while remaining employed...

  14. Time-Local Equation for the Exact Optimized Effective Potential in Time-Dependent Density Functional Theory

    Science.gov (United States)

    Liao, Sheng-Lun; Ho, Tak-San; Rabitz, Herschel; Chu, Shih-I.

    2017-06-01

    A long-standing challenge in the time-dependent density functional theory is to efficiently solve the exact time-dependent optimized effective potential (TDOEP) integral equation derived from orbital-dependent functionals, especially for the study of nonadiabatic dynamics in time-dependent external fields. In this Letter, we formulate a completely equivalent time-local TDOEP equation that admits a unique real-time solution in terms of time-dependent Kohn-Sham and effective memory orbitals. The time-local formulation is numerically implemented, with the incorporation of exponential memory loss to address the unaccounted for correlation component in the exact-exchange-only functional, to enable the study of the many-electron dynamics of a one-dimensional hydrogen chain. It is shown that the long time behavior of the electric dipole converges correctly and the zero-force theorem is fulfilled in the current implementation.

  15. Distillation time effect on lavender essential oil yield and composition.

    Science.gov (United States)

    Zheljazkov, Valtcho D; Cantrell, Charles L; Astatkie, Tess; Jeliazkova, Ekaterina

    2013-01-01

    Lavender (Lavandula angustifolia Mill.) is one of the most widely grown essential oil crops in the world. Commercial extraction of lavender oil is done using steam distillation. The objective of this study was to evaluate the effect of the length of the distillation time (DT) on lavender essential oil yield and composition when extracted from dried flowers. Therefore, the following distillation times (DT) were tested in this experiment: 1.5 min, 3 min, 3.75 min, 7.5 min, 15 min, 30 min, 60 min, 90 min, 120 min, 150 min, 180 min, and 240 min. The essential oil yield (range 0.5-6.8%) reached a maximum at 60 min DT. The concentrations of cineole (range 6.4-35%) and fenchol (range 1.7-2.9%) were highest at the 1.5 min DT and decreased with increasing length of the DT. The concentration of camphor (range 6.6-9.2%) reached a maximum at 7.5-15 min DT, while the concentration of linalool acetate (range 15-38%) reached a maximum at 30 min DT. Results suggest that lavender essential oil yield may not increase after 60 min DT. The change in essential oil yield, and the concentrations of cineole, fenchol and linalool acetate as DT changes were modeled very well by the asymptotic nonlinear regression model. DT may be used to modify the chemical profile of lavender oil and to obtain oils with differential chemical profiles from the same lavender flowers. DT must be taken into consideration when citing or comparing reports on lavender essential oil yield and composition.

  16. Effects of phytoestrogen on sexual development

    Directory of Open Access Journals (Sweden)

    Shin Hye Kim

    2012-08-01

    Full Text Available Phytoestrogen is an estrogenic compound that occurs naturally in plants. The most common sources of phytoestrogen are soybean products, which contain high levels of isoflavones. This compound, which has structural similarity with estrogen, can act as an estrogen receptor agonist or antagonist. Animal studies provide evidence of the significant effects of phytoestrogen on sexual development, including altered pubertal timing, impaired estrous cycling and ovarian function, and altered hypothalamus and pituitary functions. Although human studies examining the effects of phytoestrogen on sexual development are extremely limited, the results of some studies agree with those of the animal studies. In this paper, we review the possible mechanism of phytoestrogen action and the evidence showing the effects of phytoestrogen on sexual development in animal and human studies.

  17. Effect of myopia onset time for macula choroidal thickness

    Directory of Open Access Journals (Sweden)

    Shi-Ming Wang

    2016-03-01

    Full Text Available AIM:To investigate the effect of onset time(Tfor macula choroidal thickness(CTin myopia patient. METHODS:A prospective cohort study was designed.One hundred and twenty-two myopia patients(244 eyes; 67 male and 55 female; aged 30~41 years, mean 35.1±4.6 years oldwho received preoperative examinations from March 2014 to April 2015 were recruited in this study. The patients were divided into three groups according to onset time(T:group A(T≤5a, group B(5aF=1.56,P>0.05,age(F=2.13,P>0.05,best corrected visual acuity(BCVA, F=1.41,P>0.05,corneal curvature(F=1.65,P>0.05and axial length(F=1.89,P>0.05among the three groups. The choroid in macular region was measured by enhanced depth imaging(EDIusing spectral-domain optical coherence tomography(SD-OCT. This study recorded the CT at subfoveal(SFCT, 1mm at temporal(T1mm, nasal(N1mm, superior(S1mmand inferior(I1mmto the fovea and 3mm temporal(T3mm, nasal(N3mm, superior(S3mmand inferior(I3mmto the fovea, respectively. The differences of CT at the same position among the three groups were analyzed.RESULTS:The mean SFCT for group A,B,C were 238.32±57.95μm, 230.58±67.21μm, 221.63±62.37μm respectively in this study. The CT was found no significant difference in different locations except N3mm(tA-B=4.34,P3mm(tB-C=7.61,P3mm(t=0.76,P>0.05between group A and C. Significant difference was found at N3mm(tA-B=4.31,t B-C=7.59,tA-C=12.18; PCONCLUSION:The choroidal thickness decreases as the myopia onset time is earlier, especially at nasal.

  18. Effects of occurrence and time uncertainties on reaction and movement times of children.

    Science.gov (United States)

    Ozmun, J C; Surburg, P R; Cleland, F E

    1989-06-01

    This study investigated the influence of catch trial (CT) occurrence and foreperiod variation on reaction time and movement time of children of different ages. 48 children were randomly assigned to a CT group or a no-CT group. All received randomly ordered foreperiods. The presence of CTs and varying foreperiods played an inhibitory role in the motor performance of children.

  19. Effect Of Vibration Amplitude Level On Seated Occupant Reaction Time

    Directory of Open Access Journals (Sweden)

    Amzar Azizan

    2015-08-01

    Full Text Available The past decade has seen the rapid development of vibration comfort in the automotive industry. However little attention has been paid to vibration drowsiness. Eighteen male volunteers were recruited for this experiment. Before commencing the experiment total transmitted acceleration measured at interfaces between the seat cushion and seatback to human body was adjusted to become 0.2 ms-2 r.m.s and 0.4 ms-2 r.m.s for each volunteer. Seated volunteers were exposed to Gaussian random vibration with frequency band 1-15 Hz at two level of amplitude low vibration amplitude and medium vibration amplitude for 20-minutes in separate days. For the purpose of drowsiness measurement volunteers were asked to complete 10-minutes PVT test before and after vibration exposure and rate their subjective drowsiness by giving score using Karolinska Sleepiness Scale KSS before vibration every 5-minutes interval and following 20-minutes of vibration exposure. Strong evidence of drowsiness was found as there was a significant increase in reaction time and number of lapse following exposure to vibration in both conditions. However the effect is more apparent in medium vibration amplitude. A steady increase of drowsiness level can also be observed in KSS in all volunteers. However no significant differences were found in KSS between low vibration amplitude and medium vibration amplitude. The results of this investigation suggest that exposure to vibration has an adverse effect on human alertness level and more pronounced at higher vibration amplitude. Taken together these findings suggest a role of vibration in promoting drowsiness especially at higher vibration amplitude.

  20. 青春期女生接触媒体性知识与其感知及态度关联分析%Relationships between pubertal development and perception of sex media messages among adolescent girls

    Institute of Scientific and Technical Information of China (English)

    余春艳; 楼超华; 王子亮; 廉启国; 左霞云; 钟向阳; 程艳

    2013-01-01

    Objective To examine the influence of the status and timing of pubertal development on the perceptions of sex media messages among adolescent girls, and to provide fundamental basis for targeted sexual health education. Methods An anonymous computer-assisted self interview survey on Pubertal Development and Exposure to Sex Media Messages in Junior School Students in Shanghai was conducted among 1 390 senior and junior high school students by using stratified cluster sampling. Data of 496 girls were included in the final analysis to examine correlations among age, pubertal timing and interests, contents as well as perceptions of sex media messages. Results The more maturing the female students were, the more interested they were in sex media messages (P<0.01), the more likely they were exposed with sex messages except for HIV/STD, and more likely to interpret the messages as approval of adolescent sexual behaviors (P=0. 006). After control of age, girls with earlier pubertal timing were more interested in sex media messages [P = 0.023) and more likely to interpret the messages as approval of adolescent sexual behaviors (P=0.051). Conclusion Girls with earlier pubertal timing are more likely to be attracted by sex media messages and deem media with high approval on adolescent sexual behaviors. More attention should be paid to those girls about their exposure to sex media messages. Positive sexual attitudes and values should be built up to prevent against engaging in early sexual behaviors.%目的 探讨青春发育阶段和青春发动时相对青少年女性接触媒体传达的性知识与性态度的影响,为开展有针对性的性健康教育提供理论依据.方法 在上海市分层整群抽取6所学校的初、高中学生共1 390名,进行匿名电子问卷形式的“上海市中学生青春期健康及接触媒体状况的抽样调查”,选择其中496名处于不同青春发育阶段的青少年女性,分析年龄、青春发动时相与对媒

  1. Contagion effects in a chartist fundamentalist model with time delays

    Science.gov (United States)

    Dibeh, Ghassan

    2007-08-01

    In this paper two models of speculative markets are developed to study the effects of feedback mechanisms in financial markets. In the first model, a crash market model couples a linear chartist-fundamentalist model with time delays with a log-periodic market index I(t) through direct coupling. Numerical solutions to the model show that asset prices exhibit significant persistence as a result of the coupling to the log-periodic market index. An extension to include endogenous wealth dynamics shows that the chartists benefit from the persistent dynamics induced by the coupling. The second model is a two-asset model represented by a 2-dimensional delay-differential equation. Asset one price exhibits limit cycle dynamics while in the second market asset prices follow stable damped oscillations. The markets are coupled through a diffusive coupling term. Solutions to the coupled model show that the dynamics of asset two changes fundamentally with the price now exhibiting a limit cycle. The stable converging dynamics is replaced with limit cycle oscillations around the fundamental.

  2. Nonlinear dynamics of wind waves: multifractal phase/time effects

    Directory of Open Access Journals (Sweden)

    R. H. Mellen

    1994-01-01

    Full Text Available In addition to the bispectral coherence method, phase/time analysis of analytic signals is another promising avenue for the investigation of phase effects in wind waves. Frequency spectra of phase fluctuations obtained from both sea and laboratory experiments follow an F-β power law over several decades, suggesting that a fractal description is appropriate. However, many similar natural phenomena have been shown to be multifractal. Universal multifractals are quantified by two additional parameters: the Lévy index 0 α 2 for the type of multifractal and the co-dimension 0 C1 1 for intermittence. The three parameters are a full statistical measure the nonlinear dynamics. Analysis of laboratory flume data is reported here and the results indicate that the phase fluctuations are 'hard multifractal' (α > 1. The actual estimate is close to the limiting value α = 2,  which is consistent with Kolmogorov's lognormal model for turbulent fluctuations. Implications for radar and sonar backscattering from the sea surface are briefly considered.

  3. Effects of Finite-time Singularities on Gravitational Waves

    CERN Document Server

    Kleidis, K

    2016-01-01

    We analyze the impact of finite-time singularities on gravitational waves, in the context of $F(R)$ gravity. We investigate which singularities are allowed to occur during the inflationary era, when gravitational waves are considered, and we discuss the quantitative implications of each allowed singularity. As we show, only a pressure singularity, the so-called Type II and also a Type IV singularity are allowed to occur during the inflationary era. In the case of a Type II, the resulting amplitude of the gravitational wave is zero or almost zero, hence this pressure singularity has a significant impact on the primordial gravitational waves. The case of a Type IV singularity is more interesting since as we show, the singularity has no effect on the amplitude of the gravitational waves. Therefore, this result combined with the fact that the Type IV singularity affects only the dynamics of inflation, leads to the conclusion that the Universe passes smoothly through a Type IV singularity.

  4. The culture of time in neuropsychological assessment: exploring the effects of culture-specific time attitudes on timed test performance in Russian and American samples.

    Science.gov (United States)

    Agranovich, Anna V; Panter, A T; Puente, Antonio E; Touradji, Pegah

    2011-07-01

    Cultural differences in time attitudes and their effect on timed neuropsychological test performance were examined in matched non-clinical samples of 100 Russian and American adult volunteers using 8 tests that were previously reported to be relatively free of cultural bias: Color Trails Test (CTT); Ruff Figural Fluency Test (RFFT); Symbol Digit Modalities Test (SDMT); and Tower of London-Drexel Edition (ToL(Dx)). A measure of time attitudes, the Culture of Time Inventory (COTI-33) was used to assess time attitudes potentially affecting time-limited testing. Americans significantly outscored Russians on CTT, SDMT, and ToL(Dx) (p,.05) while differences in RFFT scores only approached statistical significance. Group differences also emerged in COTI-33 factor scores, which partially mediated differences in performance on CTT-1, SDMT, and ToL(Dx) initiation time, but did not account for the effect of culture on CTT-2. Significant effect of culture was revealed in ratings of familiarity with testing procedures that was negatively related to CTT, ToL(Dx), and SDMT scores. Current findings indicated that attitudes toward time may influence results of time limited testing and suggested that individuals who lack familiarity with timed testing procedures tend to obtain lower scores on timed tests.

  5. The ultrasound appearance of the patellar tendon attachment to the tibia in young athletes is conditional on gender and pubertal stage.

    Science.gov (United States)

    Ducher, Gaele; Cook, Jill; Lammers, Greg; Coombs, Peter; Ptazsnik, Ron; Black, Jeni; Bass, Shona L

    2010-01-01

    This cross-sectional study investigated the imaging appearance of the patellar tendon attachment to the tibia in young male and female tennis players of different ages and pubertal status. Forty-four competitive young players, who had been playing tennis at least for 2 years, were recruited from a tennis school and local tennis clubs. All subjects had bilateral ultrasound imaging of the patellar tendon attachment to the tibia. Standard anthropometric measurements, pubertal status and injury history were recorded. Ultrasound appearance of the patellar tendon attachment was categorised into three stages: cartilage attachment, insertional cartilage and mature attachment. Cartilage attachment was more prevalent in boys (32%) and extended further into puberty (until Tanner stage 4) compared to girls (6% and Tanner stage 1). Tendons with Osgood-Schlatter Disease symptoms (n=3) did not have a cartilage attachment. Imaging appearance commonly seen in young active athletes, consistent with a clinical diagnosis of OSD, was more common in boys and in the pre- and peri-pubertal stages.

  6. Effects of Time Management Instruction on Adolescents' Ability to Self-Manage Time in a Vocational Setting

    Science.gov (United States)

    DiPipi-Hoy, Caroline; Jitendra, Asha K.; Kern, Lee

    2009-01-01

    This study investigated the effectiveness of a time self-management intervention in the work setting of four adolescents with developmental disabilities. A multiple baseline across participants design was used to examine the adolescents' ability to independently identify time and initiate work-related activities. Intervention was delivered by…

  7. Effect of Full-Time versus Part-Time School Nurses on Attendance of Elementary Students with Asthma

    Science.gov (United States)

    Telljohann, Susan K.; Dake, Joseph A.; Price, James H.

    2004-01-01

    Asthma, the most common chronic disease in children today, is the leading cause of absenteeism among students. It accounts for nearly 20 million lost school days annually. This study examined whether full-time (5 days per week) or part-time (2 days per week) school nurses would have a differential effect on the frequency of absences among…

  8. Effects of Time Management Instruction on Adolescents' Ability to Self-Manage Time in a Vocational Setting

    Science.gov (United States)

    DiPipi-Hoy, Caroline; Jitendra, Asha K.; Kern, Lee

    2009-01-01

    This study investigated the effectiveness of a time self-management intervention in the work setting of four adolescents with developmental disabilities. A multiple baseline across participants design was used to examine the adolescents' ability to independently identify time and initiate work-related activities. Intervention was delivered by…

  9. Onset of effects of testosterone treatment and time span until maximum effects are achieved

    Science.gov (United States)

    Saad, Farid; Aversa, Antonio; Isidori, Andrea M; Zafalon, Livia; Zitzmann, Michael; Gooren, Louis

    2011-01-01

    Objective Testosterone has a spectrum of effects on the male organism. This review attempts to determine, from published studies, the time-course of the effects induced by testosterone replacement therapy from their first manifestation until maximum effects are attained. Design Literature data on testosterone replacement. Results Effects on sexual interest appear after 3 weeks plateauing at 6 weeks, with no further increments expected beyond. Changes in erections/ejaculations may require up to 6 months. Effects on quality of life manifest within 3–4 weeks, but maximum benefits take longer. Effects on depressive mood become detectable after 3–6 weeks with a maximum after 18–30 weeks. Effects on erythropoiesis are evident at 3 months, peaking at 9–12 months. Prostate-specific antigen and volume rise, marginally, plateauing at 12 months; further increase should be related to aging rather than therapy. Effects on lipids appear after 4 weeks, maximal after 6–12 months. Insulin sensitivity may improve within few days, but effects on glycemic control become evident only after 3–12 months. Changes in fat mass, lean body mass, and muscle strength occur within 12–16 weeks, stabilize at 6–12 months, but can marginally continue over years. Effects on inflammation occur within 3–12 weeks. Effects on bone are detectable already after 6 months while continuing at least for 3 years. Conclusion The time-course of the spectrum of effects of testosterone shows considerable variation, probably related to pharmacodynamics of the testosterone preparation. Genomic and non-genomic effects, androgen receptor polymorphism and intracellular steroid metabolism further contribute to such diversity. PMID:21753068

  10. Exposição ambiental a interferentes endócrinos com atividade estrogênica e sua associação com distúrbios puberais em crianças Environmental exposure to endocrine disruptors with estrogenic activity and the association with pubertal disorders in children

    Directory of Open Access Journals (Sweden)

    Crésio Alves

    2007-05-01

    Full Text Available A substância exógena que causa efeitos adversos na saúde de um organismo ou sua descendência, como resultado de distúrbios na função hormonal, é denominada interferente endócrino. Nos últimos anos, produtos ambientais com atividades hormonais têm sido documentados como causadores de anormalidades puberais ou reprodutivas em animais. Os poucos casos comprovados em humanos foram aqueles relacionados a exposições acidentais. Apesar disso, pediatras e pais recomendam a suspensão de todos os alimentos potencialmente contaminados, em especial carne (aves, gado e derivados da soja quando a criança apresenta alguma alteração puberal. Estas recomendações, se não embasadas cientificamente, podem ter conseqüências deletérias, não apenas pela eliminação de fontes protéicas da dieta, como também por retardar a investigação de causas tratáveis. Por outro lado, a não investigação dos efeitos adversos destes produtos é da mesma forma danosa. Esta revisão descreve os principais interferentes endócrinos responsáveis por alterações puberais em humanos e conclui que, excetuando exposições acidentais a altas quantidades destes produtos, mais estudos são necessários para responsabilizar a ação crônica e em baixas doses destas substâncias na alteração do tempo de desenvolvimento puberal em nossa espécie.Endocrine disruptors are exogenous substances with adverse health effects in intact organisms or their progeny, secondary to changes in endocrine function. Recent years have witnessed constant reports of environmental factors with hormone-like effects causing pubertal or reproductive abnormalities in animals. The few cases proven to be associated with pubertal disorders in humans have been related to accidental exposure. Nevertheless, pediatricians and parents recommend suspending all possible estrogen-contaminated food, especially meat (poultry, beef and soy products, when the child presents with a pubertal disorder

  11. Effects of passive computer use time and non-computer work time on the performance of electronic activity monitoring.

    Science.gov (United States)

    Hwang, Yaw-Huei; Chen, Yen-Ting; Yeh, Jao-Yu; Liang, Huey-Wen

    2010-10-01

    This study aimed to examine the effects of passive and non-computer work time on the estimation of computer use times by electronic activity monitoring. A total of 20 subjects with computers were monitored for 3 h. Average relative error for total computer use time estimation was about 4%, given that non-computer work time was 20% of the 3-h monitored period. No significant impact of passive computer use time was found in this study. Non-computer work time of 40% or less is suggested as criteria for the application of electronic activity monitoring to ensure reliability in the physical work loading assessment. Statement of Relevance: This research studied the criteria of non-computer work time for the appropriate use of electronic activity monitoring to ensure reliability in the assessment of physical work loading. It is suggested that it should be set to 40% or less of the 3-h monitoring period.

  12. The Effect of Pulsar Timing Noise and Glitches on Timing Analysis for Ground Based Telescopes Observation

    Science.gov (United States)

    Oña-Wilhelmi, E.; de Jager, O. C.; Contreras, J. L.; de los Reyes, R.; Fonseca, V.; López, M.; Lucarelli, F.; MAGIC Collaboration

    2003-07-01

    Pulsed emission from a number of gamma-ray pulsars is expected to be detectable with next generation ground-based gamma-ray telescopes such as MAGIC and possibly H.E.S.S. within a few hours of observations. The sensitivity is however not sufficient to enable a detection within a few seconds as reached by radio surveys. In some cases we may be fortunate to do a period search given a few hours' data, but if the signal is marginal, the correct period parameters must be known to allow a folding of the gamma-ray arrival times. The residual phases are then sub jected to a test for uniformity from which the significance of a signal can be assessed. If contemporary radio parameters are not available, we have to extrap olate archival radio parameters to the observation time in question. Such an extrap olation must then be accurate enough to avoid significant pulse smearing. The pulsar ephemerides from the archival data of HartRAO and Princeton (b etween 1989 and 1998) provide an excellent opportunity to study the accuracy of extrap olations of such ephemerides to the present moment, if an appropriate time shift is intro duced. The aim of this study is to investigate the smear in the gamma-ray pulse profile during a single night of observations.

  13. Anomalous multiphoton photoelectric effect in ultrashort time scales.

    Science.gov (United States)

    Kupersztych, J; Raynaud, M

    2005-09-30

    In a multiphoton photoelectric process, an electron needs to absorb a given number of photons to escape the surface of a metal. It is shown for the first time that this number is not a constant depending only on the characteristics of the metal and light, but varies with the interaction duration in ultrashort time scales. The phenomenon occurs when electromagnetic energy is transferred, via ultrafast excitation of electron collective modes, to conduction electrons in a duration less than the electron energy damping time. It manifests itself through a dramatic increase of electron production.

  14. RETENTION TIME EFFECT ON METAL REMOVAL BY PEAT COLUMNS

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, E

    2007-02-28

    The potential use of a peat bed to treat the H-12 Outfall discharge to bring it to new compliance limits was previously investigated and reported utilizing a 7 hour retention time. The influence of retention time (contact time) of water with peat moss on the removal of copper from the water was investigated under laboratory conditions using vertical flow peat moss columns. Reduction of the necessary retention time has a large influence on the design sizing of any peat bed that would be constructed to treat the H-12 discharge on a full scale basis. Retention times of 5 hours, 3 hours and 1 hour were tested to determine the copper removal by the peat columns using vertical flow. Water samples were collected after 4, 8, 12, and 16 water volumes had passed through the columns and analyzed for a suite of metals, with quantitative emphasis on copper. Laboratory results indicated that copper removal was very high at each of the 3 retention times tested, ranging from 99.6 % removal at 5 and 3 hours to 98.8% removal at 1 hour. All these values are much lower that the new compliance limit for the outfall. The results also indicated that most divalent metals were removed to their normal reporting detection limit for the analytical methods used, including zinc. Lead levels in the H-12 discharge used in this study were below PQL in all samples analyzed. While each of the retention times studied removed copper very well, there were indications that 1 hour is probably too short for an operational, long-term facility. At that retention time, there was about 6% compaction of the peat in the column due to the water velocity, and this may affect long term hydraulic conductivity of the peat bed. At that retention time, copper concentration in the effluent was higher than the other times tested, although still very low. Because of the potential compacting and somewhat reduced removal efficiency at a 1 hour retention time, it would be prudent to design to at least a 3 hour retention

  15. Finite correlation time effects in kinematic dynamo problem

    Energy Technology Data Exchange (ETDEWEB)

    Schekochihin, A.A.; Kulsrud, R.M.

    2000-02-11

    One-point statistics of the magnetic fluctuations in kinematic regime with large Prandtl number and non delta-correlated in time advecting velocity field are studied. A perturbation expansion in the ratio of the velocity correlation time to the dynamo growth time is constructed in the spirit of the Kliatskin-Tatarskii functional method and carried out to first order. The convergence properties are improved compared to the commonly used van Kampen-Terwiel method. The zeroth-order growth rate of the magnetic energy is estimated to be reduced (in three dimensions) by approximately 40%. This reduction is quite close to existing numerical results.

  16. Probing the noncommutative effects of phase space in the time-dependent Aharonov-Bohm effect

    CERN Document Server

    Ma, Kai; Yang, Huan-Xiong

    2016-01-01

    We study the noncommutative corrections on the time-dependent Aharonov-Bohm effect when both the coordinate-coordinate and momentum-momentum noncommutativities are considered. This study is motivated by the recent observation that there is no net phase shift in the time-dependent AB effect on the ordinary space, and therefore tiny derivation from zero can indicate new physics. The vanishing of the time-dependent AB phase shift on the ordinary space is preserved by the gauge and Lorentz symmetries. However, on the noncomutative phase space, while the ordinary gauge symmetry can be kept by the Seiberg-Witten map, but the Lorentz symmetry is broken. Therefore nontrivial noncommutative corrections are expected. We find there are three kinds of noncommutative corrections in general: 1) $\\xi$-dependent correction which comes from the noncommutativity among momentum operators; 2) momentum-dependent correction which is rooted in the nonlocal interactions in the noncommutative extended model; 3) momentum-independent c...

  17. Effect of Retention Time on Biogas Production from Poultry ...

    African Journals Online (AJOL)

    JPC

    Daily gas production fell slightly from 130 to 32 litres as retention time was increased from. 10 to 40 days .... Total alkalinity, ammonia nitrogen and .... Information and Advisory Service on Appropriate Technology (Isat) Biogas Basic. (gtz) vol. 1.

  18. Effect of emergency physician burnout on patient waiting times.

    Science.gov (United States)

    De Stefano, Carla; Philippon, Anne-Laure; Krastinova, Evguenia; Hausfater, Pierre; Riou, Bruno; Adnet, Frederic; Freund, Yonathan

    2017-07-04

    Burnout is common in emergency physicians. This syndrome may negatively affect patient care and alter work productivity. We seek to assess whether burnout of emergency physicians impacts waiting times in the emergency department. Prospective study in an academic ED. All patients who visited the main ED for a 4-month period in 2016 were included. Target waiting times are assigned by triage nurse to patients on arrival depending on their severity. The primary endpoint was an exceeded target waiting time for ED patients. All emergency physicians were surveyed by a psychologist to assess their level of burnout using the Maslach Burnout Inventory. We defined the level of burnout of the day in the ED as the mean burnout level of the physicians working that day (8:30 to the 8:30 the next day). A logistic regression model was performed to assess whether burnout level of the day was independently associated with prolonged waiting times, along with previously reported predictors. Target waiting time was exceeded in 7524 patients (59%). Twenty-six emergency physicians were surveyed. Median burnout score was 35 [Interquartile (24-49)]. A burnout level of the day higher than 35 was independently associated with an exceeded target waiting time (adjusted odds ratio 1.54, 95% confidence interval 1.39-1.70), together with previously reported predictors (i.e., day of the week, time of the day, trauma, age and daily census). Burnout of emergency physicians was independently associated with a prolonged waiting time for patients visiting the ED.

  19. Advantages of Parallel Processing and the Effects of Communications Time

    Science.gov (United States)

    Eddy, Wesley M.; Allman, Mark

    2000-01-01

    Many computing tasks involve heavy mathematical calculations, or analyzing large amounts of data. These operations can take a long time to complete using only one computer. Networks such as the Internet provide many computers with the ability to communicate with each other. Parallel or distributed computing takes advantage of these networked computers by arranging them to work together on a problem, thereby reducing the time needed to obtain the solution. The drawback to using a network of computers to solve a problem is the time wasted in communicating between the various hosts. The application of distributed computing techniques to a space environment or to use over a satellite network would therefore be limited by the amount of time needed to send data across the network, which would typically take much longer than on a terrestrial network. This experiment shows how much faster a large job can be performed by adding more computers to the task, what role communications time plays in the total execution time, and the impact a long-delay network has on a distributed computing system.

  20. Ethnic differences in body fat distribution among Asian pre-pubertal children: A cross-sectional multicenter study

    Directory of Open Access Journals (Sweden)

    Koon Poh Bee

    2011-06-01

    Full Text Available Abstract Background Ethnic differences in body fat distribution contribute to ethnic differences in cardiovascular morbidities and diabetes. However few data are available on differences in fat distribution in Asian children from various backgrounds. Therefore, the current study aimed to explore ethnic differences in body fat distribution among Asian children from four countries. Methods A total of 758 children aged 8-10 y from China, Lebanon, Malaysia and Thailand were recruited using a non-random purposive sampling approach to enrol children encompassing a wide BMI range. Height, weight, waist circumference (WC, fat mass (FM, derived from total body water [TBW] estimation using the deuterium dilution technique and skinfold thickness (SFT at biceps, triceps, subscapular, supraspinale and medial calf were collected. Results After controlling for height and weight, Chinese and Thai children had a significantly higher WC than their Lebanese and Malay counterparts. Chinese and Thais tended to have higher trunk fat deposits than Lebanese and Malays reflected in trunk SFT, trunk/upper extremity ratio or supraspinale/upper extremity ratio after adjustment for age and total body fat. The subscapular/supraspinale skinfold ratio was lower in Chinese and Thais compared with Lebanese and Malays after correcting for trunk SFT. Conclusions Asian pre-pubertal children from different origins vary in body fat distribution. These results indicate the importance of population-specific WC cut-off points or other fat distribution indices to identify the population at risk of obesity-related health problems.