A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, infulfilment of the requirements for the .degree Doctor of Philosophy Johannesburg ' 1989

Vocal communication is central to the coordination of social behavior in many vertebrate species, and it has been particularly well studied in songbirds, which use their songs in different contexts to convey information about the singer or its environment (Catchpole and Slater 2008; Alger et al. 2016). While it is widely accepted that the songs of oscine passerine birds (the songbirds) have two main social functions: intrasexual competition, and courtship (Catchpole and Slater 2008), the evolution of large and complex song repertoires remains an evolutionary puzzle (Byers and Kroodsma 2009). The question is: why do some songbird species produce an elaborate vocal repertoire, while other species carry out courtship and competition with a far smaller and simpler repertoire? In this thesis I examine the adaptive value (social function) of song in malemale competition with an eye toward understanding how intrasexual selection may have driven the elaboration of the male Bachman’s sparrow (Peucea aestivalis) vocal repertoire. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2019. / FAU Electronic Theses and Dissertations Collection

The prevalence of nonmarital sexual behavior among adolescents continues to rise, as does the number of sexually transmitted diseases, AIDS, and unwanted pregnancies. College-age adolescents appear to be even more susceptible to these problems. Sound theoretical knowledge would seem useful in designing more effective prevention programs. The purpose of this study was to identity theoretical factors that contribute to or decrease such behaviors. Two hundred fifty-two single college students completed measures designed to examine relations among identity development, attachment patterns, gender, and sexual behavior in older adolescents. Attachment and identity measures were used to explore variations in sexual behavior relating to identity development and the quality of intimate relationships formed in late adolescence. Three measures were used to assess these theoretical constructs and to measure sexual behavior: The Personal Opinion Survey contains Grotevant and Adams' 64-item Extended Version of the Objective Measure ofEgo Identity Status; a modified version of Simpson, Rholes, and Nelligan's 13-item Attachment Style measure; and 19 items that assess sexual behaviors. Results confirmed statistically significant relations among identity development, attachment patterns, gender, and sexual behavior. Specifically, correlational analyses confirmed relations among identity, attachment, and premarital intercourse, age of first intercourse, and items pertaining to risky sexual behavior. Identity was also statistically significantly related to premarital intercourse. Attachment and identity sub scale scores were predictive of sexual behavior when multiple regression equations were generated. Previous studies of identity, gender, and intimacy among older adolescents support the findings ofthis study. Other researchers have found relationships between attachment and intimacy among this population. The results of this study and future research areas are discussed.

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Thesis (Ph.D.) -- McMaster University, 2007. / Supervisor: Sigal Balshine Includes bibliographical references.

Graduation date: 1998

The purposes of this study are illustrated as follows: to investigate the current situation of demography, internet pornography experience, sexual attitude and behavior among senior high school students, to exam the difference and correlation of those students¡¦demography which is represented on internet pornography experience and sexual attitude, and to try to find out the variables of pornography experience and population, which could be used to predict senior high school students¡¦ sexual attitude in such environment which internet pornography overloads. The data gathered from questionnaires are analyzed by statistical methods such as frequency distributions, mean deviation, reliability analysis, factor analysis, chi-square test, t-test of dependent sample, ANOVA of dependent sample, Pearson¡¦s correlation, and the multiple regression. Results and discussion are summarized as follows: 1. There are 63.7% senior high school students have touch the internet for 5 years, and the degree increase by the years that they touched. They usually talk and make friend on the internet(78.7%) . 2. There are 71.1% senior high school students have touch the internet pornography, and that is they main way to connect the pornography. They touched it for vagary, and they touched it for one hour a day, in nine in the night to twelve in the noon. They touched it at their home. 3. The senior high school students¡¦ sexual attitude is between agree and disagree. 4. There are 10.5% students have sexual behavior, which gather 15 to 17 years old. The contraception they usually took is condom. 5. Sex, school, talking about sexual issues with friend have significant different to internet pornography experience. 6. Sex, grade, school, the school location have significant different to sexual attitude. 7.Internet pornography has different to sexual attitude. Without connecting internet pornography, connecting less time, and taking disagree option, the sexual attitude are more guard. 8.Internet pornography experience and sexual attitude have lower negative correlation. 9.Internet pornography has different to sexual behavior. The more connecting, the more frequency, and the more time cost the students have, their sexual behavior are deeper. 10.Internet pornography experience and sexual behavior have lower correlation. 11.Population and internet pornography information to sexual attitude can validly predict 12% senior high school students¡¦ sexual attitude. Population and internet pornography information to sexual behavior can validly predict 12.6% senior high school students¡¦ sexual behavior.

Tidiga vuxenlivet präglas av oprövade miljöer och situationer. Detta ställer höga krav på individens perception, anpassningsförmåga och attityd. En intensiv miljö flertalet unga vuxna kommer i kontakt med för första gången är krogen. Positiv attityd till riskfyllda beteenden där kan i förlängningen resultera i negativa hälsoeffekter. Syftet med denna enkätstudie var i huvudsak att undersöka unga vuxnas attityd till Verbal aggression, Rekreationellt berusningsdrickande, Riskfyllt sex, Fysisk aggression, Ekonomiskt riskfylld modekonsumtion, Ekonomiskt riskfylld festkonsumtion, Rekreationellt drogbruk och Riskfyllt spelande om pengar. Resultatet av de 256 personer som deltog visade genom variansanalys att män hade signifikant mer positiv attityd än kvinnor till fem av åtta riskbeteenden och att största skillnaden då kön, etnicitet och studieval analyserades i kombination förelåg mellan ickesvenska män och kvinnor på studieförberedande program. Klusteranalys visade på förekomst av högriskgrupp där män var i majoritet. Eventuella preventiva insatser bör i huvudsak lämpligen riktas mot unga vuxna män.