Violence in Music Videos: Examining the Prevalence and Context of Physical Aggression

The purpose of this study was to examine violence in music video programming. Using a representative sample of television content, we assessed whether the amount and context of physical aggression varied across different music video channels (BET, MTV, VH-1) and genres (adult contemporary, heavy metal, rap rhythm and blues, and rock). The results reveal that 15% of music videos feature violence, and most of that aggression is sanitized, not chastised, and presented in realistic contexts. Significant differences emerged in the prevalence and nature of violence by channel and genre, however. The findings are discussed in terms of the risk that exposure to violence in each channel and genre may be posing to viewers' learning of aggression, fear, and emotional desensitization.     

Two-year behavior outcomes of project towards no tobacco use.

Presents a 2-year follow-up data from a school-based tobacco use prevention project designed to test the effectiveness of 3 primary components in social influence programs. The components either teach refusal skills, awareness of social value misperceptions, or physical consequences. Curricula were tested with a randomized experiment involving 48 junior high schools. Data suggested that a physical-consequences curriculum is successful at attenuating increases in adolescent smokeless tobacco use, cigarette experimentation may be attenuated by various approaches, and a comprehensive program with all 3 components was necessary to attenuate increases in weekly use of both forms of tobacco. These results also indicate that school-based tobacco use interventions can be effective at least 2 years postprogram, after students make their transition to high school. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Structural-equation models of current drug use: Are appropriate models so simple(x)?

The simplex and common-factor models of drug use were compared using maximum-likelihood estimation of latent variable structural models in two samples: a sample of 226 high school students, using ratio-scale measures of current drug use, and a sample of 310 industrial workers and 811 college students, using ordinal-scale measures of current drug use. Latent variables of alcohol, marihuana, enhancer hard drugs, and dampener hard drugs were specified in a series of structural models. Contrary to previous findings with cumulative drug-use data, the common-factor model provided a more acceptable representation of the observed current-use data than did the simplex model in both samples. In addition, the similarity of results across both of these samples supports recent contentions by Huba and Bentler (1982) that quantitatively measured variables are not necessarily superior to qualitative, ordinal indicators in latent variable models of drug use. (49 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Silver nanoparticles as selective ionization probes for analysis of olefins by mass spectrometry

Laser desorption/ionization (LDI) using silver nanoparticles (AgNPs) is shown to selectively ionize olefinic compounds, e.g., cholesterol, 1-palmitoyl-2-oleoyl- sn-glycero-3-phosphocholine (POPC), and carotenoids. Selective AgNP LDI can be carried out from complex mixtures without the addition of an organic matrix, sample cleanup, or prefractionation. Results presented in this report are the first to demonstrate the selective ionization of specific compounds from a complex mixture using metal nanoparticles.     

Working memory capacity moderates the predictive effects of drug-related associations on substance use.

Some theories suggest that spontaneously activated, drug-related associations in memory may have a "freer reign" in predicting drug use among individuals with lower working memory capacity. This study evaluated this hypothesis among 145 at-risk youth attending continuation high schools (CHS). This is the 1st study to evaluate this type of dual-process interaction in the prediction of drug use among a sample of at-risk adolescents. The CHS students completed assessments of drug-related memory associations, working memory capacity, and drug use. Control variables included age, gender, ethnicity, and acculturation. Robust multiple regression using least trimmed squares estimation indicated that there was a significant linear by linear interaction between working memory capacity (assessed with the self-ordered pointing task) and drug-related associations (assessed with verb generation and cue-behavior association tasks) in the prediction of alcohol and cigarette use. Consistent with dual-process cognitive theories, drug-related associations in memory predicted drug use more strongly in students with lower levels of working memory capacity. These findings add to the literature implicating the influence of dual cognitive processes in adolescent risk behaviors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Microfluidic deans switch for comprehensive two-dimensional gas chromatography

A microfluidic Deans switch was used as a comprehensive two-dimensional gas chromatography (GCxGC) modulator. The simplicity and wide temperature range of the Deans switch make it a promising alternative to existing modulation techniques. However, the Deans switch is a low duty cycle modulator; that is, it samples only a small portion of the primary column effluent. Like all low duty cycle modulators, the Deans switch produces inconsistent transfer of components from the primary to the secondary column if the primary peaks are undersampled. Theoretical simulations and experimental studies show that the relative standard deviation (RSD) of the fraction of material transferred from the primary column to the secondary column is less than 1% if the modulation ratio is greater than 2.5. But the RSDs increase rapidly as the modulation ratio is decreased below 2.5. Deans switch GCxGC was validated by analyzing the aromatic content of gasoline. A fast analysis (<10 min) produced narrow primary peaks and a modulation ratio of 1.7. The quantitative results were in good agreement with results obtained with differential flow modulation GCxGC and GC/MS, but the RSDs of single-component levels were approximately three times greater. The Deans switch modulator was also used for a slower gasoline analysis (33 min run time) that produced modulation ratios near 5. In this case, the quantitative results and RSDs were in excellent agreement with the differential flow GCxGC and GC/MS results. These studies demonstrate that a Deans switch can be an effective modulator provided that modulation ratios greater than approximately 2.5 are employed.     

Parameter Estimation for a Generalized Gamma Distribution

It is fairly commonplace in reliability analyses to encounter data which is incompatible with the exponential, Weibull, and other familiar probability models. Such data motivates research to enlarge the group of probability distributions which are useful to the reliability analyst.

In this paper, we examine a three-parameter generalization of the gamma distribution and derive parameter estimation techniques for that distribution. Those techniques, in the general case, depend upon method of moments considerations which lead to simultaneous equations for which closed form solutions are not available. Graphic solution is proposed and aids to the computations are provided. Major concepts in the paper are summarized by means of a numerical example.

Details are given for the special case in which only the scale parameter is unknown. Three unbiased estimators for that parameter are derived along with their variance formulas. Minimum variance considerations are discussed by application of the Cramér-Rao Theorem.