Non-linear state space modelling of fisheries biomass dynamics by using Metropolis-Hastings within-Gibbs sampling

State space modelling and Bayesian analysis are both active areas of applied research in fisheries stock assessment. Combining these two methodologies facilitates the fitting of state space models that may be non-linear and have non-normal errors, and hence it is particularly useful for modelling fisheries dynamics. Here, this approach is demonstrated by fitting a non-linear surplus production model to data on South Atlantic albacore tuna ( Thunnus alalunga ). The state space approach allows for random variability in both the data (the measurement of relative biomass) and in annual biomass dynamics of the tuna stock. Sampling from the joint posterior distribution of the unobservables was achieved by using Metropolis-Hastings within-Gibbs sampling.     

Managing Threat: Do Social‐Cognitive Processes Mediate the Link Between Peer Victimization and Adjustment Problems in Early Adolescence?

Peer victimization has been linked concurrently and over time with multiple adjustment problems. However, the reasons for this multi‐finality in victimization are not well understood. The current study examines social‐cognitive processes (hostile attributions, social perspective awareness, and interpersonal skills) as mediators of the relations between subtypes of peer victimization (relational, physical) and depression and anxiety, social withdrawal, and physical aggression in early adolescence. The overall pattern of associations among subtypes of victimization, social‐cognitive processes, and adjustment converged with expectations that victimization biases adolescents' cognitions about peers in conflict situations and skills relating to peers. In turn, these cognitions and skills differentially compromised their ability to regulate diverse emotions or limit reticent behaviors in response to peer threats. Modest gender differences in these associations were found.     

Initiating Sexual Experiences: How Do Young Adolescents Make Decisions Regarding Early Sexual Activity?

Understanding how young adolescents make decisions to engage in early sexual activities is vital for intervention efforts aimed at fostering positive youth development and reducing the negative outcomes of adolescent sexual behavior. In‐depth interviews with 42 suburban, mostly White, ninth‐grade adolescents (52% females, mean age=14.1, SD=.45) elicited accounts of their early sexual decisions. We adapted grounded theory methodology to build a model of sexual decision making from the adolescents' narratives. Six dominant categories emerged: contextual factors (relationship and personal characteristics), consideration of risks and benefits, boundary setting, boundary communication, the sexual experience, and evaluation. Our model of early sexual decision‐making processes, developed from the perspectives of young adolescents, highlights active consideration of health and social risks and benefits, as well as the generation of options regarding sexual activity. The model also shows that young adolescents set clear boundaries of sexual limits and evaluate sexual experiences, suggesting a dynamic process of decision making.     

Parental Emotion Socialization in Adolescence: Differences in Sex, Age and Problem Status

There is a paucity of research on how mothers and fathers socialize emotion in their adolescent sons and daughters. This study was based on 220 adolescents (range 11‐ to 16‐years‐old) who exhibit a range of emotional and behavioral problems and their parents. Parental responses to their children's displays of sadness, anger and fear were assessed. Mothers were found to be more engaged in their children's emotional lives than were fathers. With a few important exceptions (e.g., boys were punished for expressions of anger more than girls), adolescent girls and boys were socialized in much the same way. Parents of older adolescents were generally less supportive and more punitive toward emotional displays. Systematic links between adolescent problem status and parent approaches to emotion socialization were found. These findings on how parents socialize emotions in their adolescents have important implications for theory as well as practice.     

The Lull of Tradition: A Grounded Theory Study of Television Violence, Children and Social Work

This article results from a study of television violence and social work practice with children. Twenty-one social workers who work primarily with children in schools, in community mental health agencies and in private practice were interviewed. A qualitative analysis using grounded theory indicates that social workers do little to elicit television content or information about children's television viewing. They do not believe that television experiences are central to their work. Although social workers express concern about the influence of television violence on children, their traditional beliefs in cause and effect, values neutrality, and gender lead many to minimize its importance.     

Job Satisfaction and Intention to Seek Graduate Education

This study of the relationship between job satisfaction and intention to seek graduate education among human service workers tests the hypothesis that intention will be stronger among satisfied senior practitioners (those in their current job for three or more years) and among dissatisfied junior workers. In November 1993, a questionnaire designed to measure various aspects of both job satisfaction and intent to pursue graduate education was distributed to all 83 bachelor-level human service workers in four agencies. Moderated regression analyses, with several control variables from background information about the 67 respondents, repeatedly supported the hypothesis. Discussion also covers secondary findings, limitations of the study, and implications of the principal finding for both educators and social service administrators.     

Effect of missing plots in some response surface designs

The effect of one or more missing observations for response surface designs arranged in blocks are examined in this paper. The resu lts as applied to a central composite design with orthogonal blocking, and an equirdial design with orthogonal blocking, are reported.