Recently Arrested Adolescents are at High Risk for Sexually Transmitted Diseases

Adolescent offenders may be at high risk for sexually transmitted diseases (STDs). With previous research and interventions focused on incarcerated adolescents, data are needed on STD prevalence and risk factors among newly arrested youth released to the community, a far larger subgroup.Participants were recruited from all arrested youth processed at the Hillsborough County, Florida Juvenile Assessment Center during the last half of 2006 (506 males, 442 females). Participants voluntarily providing urine samples for drug testing as part of standard protocol were also consented to having their specimens split and tested for chlamydia and gonorrhea, using an FDA-approved nucleic acid amplification test.STD prevalence was similar to those previously reported among incarcerated adolescents: 11.5% tested positive for chlamydia, 4.2% for gonorrhea, and 13.2% for either or both infections. Prevalence was significantly higher among females: 19.2% of females had either or both infections compared with 10.5% of males. Prevalence was higher for 17 to 18 year olds (15.2% of males, 25.5% of females), blacks, detained youths, drug users, and those engaged in sexual risk behaviors. Previous STD testing experience was limited.The study indicated that a voluntary STD screening protocol is feasible for arrested youth entering the juvenile justice system, and these offenders are at high risk for STDs. Because most arrested youths are released back to the community, routine testing and treatment of recently arrested youths, and expanded access to risk reduction and prevention programs, can yield substantial public health benefits

Thermodynamic versus statistical nonequivalence of ensembles for the mean-field Blume-Emery-Griffiths model

We illustrate a novel characterization of nonequivalent statistical mechanical ensembles using the mean-field Blume-Emery-Griffiths (BEG) model as a test model. The novel characterization takes effect at the level of the microcanonical and canonical equilibrium distributions of states. For this reason it may be viewed as a statistical characterization of nonequivalent ensembles which extends and complements the common thermodynamic characterization of nonequivalent ensembles based on nonconcave anomalies of the microcanonical entropy. By computing numerically both the microcanonical and canonical sets of equilibrium distributions of states of the BEG model, we show that for values of the mean energy where the microcanonical entropy is nonconcave, the microcanonical distributions of states are nowhere realized in the canonical ensemble. Moreover, we show that for values of the mean energy where the microcanonical entropy is strictly concave, the equilibrium microcanonical distributions of states can be put in one-to-one correspondence with equivalent canonical equilibrium distributions of states. Our numerical computations illustrate general results relating thermodynamic and statistical equivalence and nonequivalence of ensembles proved by Ellis, Haven, and Turkington [J. Stat. Phys. 101, 999 (2000)].Comment: 13 pages, 4 figures, minor typos corrected and one reference adde

Brief Intervention for Truant Youth Sexual Risk Behavior and Marijuana Use

Substance use and sexual risk behaviors are common among adolescents, but research has focused attention on alcohol use. Much less is known about the relationship of marijuana use and sexual risk behavior among high-risk, especially truant, youths. We report interim findings from a NIDA-funded experimental, brief intervention (BI) study involving truant youths and their parents/guardians. Longitudinal data were analyzed to study (1) the relationships between the youths\u27 marijuana use and sexual risk behavior and (2) the effects of a substance use BI on their marijuana use and sexual risk behavior. A growth model analysis for parallel processes was conducted to study relationships between marijuana use and sexual risk behavior, and to assess the overall BI effect on linear and quadratic trends in subgroups of youth differing in their sexual risk behavior and marijuana use. Implications of the results for future research and service delivery are considered. © 2014 Copyright Taylor & Francis Group, LLC

Brief Intervention for Truant Youth Sexual Risk Behavior and Alcohol Use: A Parallel Process Growth Model Analysis

Truant youths frequently experience family problems, emotional/psychological issues, substance misuse, and delinquency. They are likely engaging in alcohol use and sexual risk behavior at a higher rate than the general youth population. Early intervention services would benefit them, their families, and society. We present interim findings from an ongoing, National Institute on Drug Abuse-funded, experimental, brief intervention (BI) study involving truant youths and their parent/guardians. Baseline, 3-, 6-, and 12-month follow-up data were analyzed to determine whether alcohol use and sexual risk behaviors were longitudinally related, to examine the effects of the BI on alcohol use and sexual risk behaviors, to identify subgroups of youths involved in alcohol use and sexual risk behaviors, and to assess the impact of the BI on these subgroups. Results indicated alcohol use and sexual risk were longitudinally related. Limited treatment effects were observed for alcohol use. Implications for future research and service delivery are considered. © 2014 Copyright Taylor & Francis Group, LLC

Brief Intervention for Truant Youth Sexual Risk Behavior and Marijuana Use

Substance use and sexual risk behaviors are common among adolescents, but research has focused attention on alcohol use. Much less is known about the relationship of marijuana use and sexual risk behavior among high-risk, especially truant, youths. We report interim findings from a NIDA-funded experimental, brief intervention (BI) study involving truant youths and their parents/guardians. Longitudinal data were analyzed to study (1) the relationships between the youths\u27 marijuana use and sexual risk behavior and (2) the effects of a substance use BI on their marijuana use and sexual risk behavior. A growth model analysis for parallel processes was conducted to study relationships between marijuana use and sexual risk behavior, and to assess the overall BI effect on linear and quadratic trends in subgroups of youth differing in their sexual risk behavior and marijuana use. Implications of the results for future research and service delivery are considered. © 2014 Copyright Taylor & Francis Group, LLC

Emotional Psychological and Related Problems Among Truant Youths: An Exploratory Latent Class Analysis

Latent class analysis was conducted on the psychosocial problems experienced by truant youths. Data were obtained from baseline interviews completed on 131 youths and their parents/guardians involved in a NIDA-funded, Brief Intervention Project. Results identified two classes of youths: Class 1(n=9) - youths with low levels of delinquency, mental health and substance abuse issues; and Class 2(n=37) - youths with high levels of these problems. Comparison of these two classes on their urine analysis test results and parent/guardian reports of traumatic events found significant (p\u3c.05) differences between them that were consistent with their problem group classification. Our results have important implications for research and practice

The Juvenile Justice Behavioral Health Services Cascade: A New Framework for Measuring Unmet Substance Use Treatment Services Needs Among Adolescent Offenders

Overview—Substance use and substance use disorders are highly prevalent among youth under juvenile justice (JJ) supervision, and related to delinquency, psychopathology, social problems, risky sex and sexually transmitted infections, and health problems. However, numerous gaps exist in the identification of behavioral health (BH) problems and in the subsequent referral, initiation and retention in treatment for youth in community justice settings. This reflects both organizational and systems factors, including coordination between justice and BH agencies. Methods and Results—This paper presents a new framework, the Juvenile Justice Behavioral Health Services Cascade (“Cascade”), for measuring unmet substance use treatment needs to illustrate how the cascade approach can be useful in understanding service delivery issues and identifying strategies to improve treatment engagement and outcomes for youth under community JJ supervision. We discuss the organizational and systems barriers for linking delinquent youth to BH services, and explain how the Cascade can help understand and address these barriers. We provide a detailed description of the sequential steps and measures of the Cascade, and then offer an example of its application from the Juvenile Justice – Translational Research on Interventions for Adolescents in the Legal System project (JJ-TRIALS), a multi-site research cooperative funded by the National Institute on Drug Abuse. Conclusion—As illustrated with substance abuse treatment, the Cascade has potential for informing and guiding efforts to improve behavioral health service linkages for adolescent offenders, developing and testing interventions and policies to improve interagency and cross-systems coordination, and informing the development of measures and interventions for improving the implementation of treatment in complex multisystem service settings

Optimal designs for rational function regression

We consider optimal non-sequential designs for a large class of (linear and nonlinear) regression models involving polynomials and rational functions with heteroscedastic noise also given by a polynomial or rational weight function. The proposed method treats D-, E-, A-, and $\Phi_p$-optimal designs in a unified manner, and generates a polynomial whose zeros are the support points of the optimal approximate design, generalizing a number of previously known results of the same flavor. The method is based on a mathematical optimization model that can incorporate various criteria of optimality and can be solved efficiently by well established numerical optimization methods. In contrast to previous optimization-based methods proposed for similar design problems, it also has theoretical guarantee of its algorithmic efficiency; in fact, the running times of all numerical examples considered in the paper are negligible. The stability of the method is demonstrated in an example involving high degree polynomials. After discussing linear models, applications for finding locally optimal designs for nonlinear regression models involving rational functions are presented, then extensions to robust regression designs, and trigonometric regression are shown. As a corollary, an upper bound on the size of the support set of the minimally-supported optimal designs is also found. The method is of considerable practical importance, with the potential for instance to impact design software development. Further study of the optimality conditions of the main optimization model might also yield new theoretical insights.Comment: 25 pages. Previous version updated with more details in the theory and additional example

An Oscillatory Contractile Pole-Force Component Dominates the Traction Forces Exerted by Migrating Amoeboid Cells

We used principal component analysis to dissect the mechanics of chemotaxis of amoeboid cells into a reduced set of dominant components of cellular traction forces and shape changes. The dominant traction force component in wild-type cells accounted for ~40% of the mechanical work performed by these cells, and consisted of the cell attaching at front and back contracting the substrate towards its centroid (pole-force). The time evolution of this pole-force component was responsible for the periodic variations of cell length and strain energy that the cells underwent during migration. We identified four additional canonical components, reproducible from cell to cell, overall accounting for an additional ~20% of mechanical work, and associated with events such as lateral protrusion of pseudopodia. We analyzed mutant strains with contractility defects to quantify the role that non-muscle Myosin II (MyoII) plays in amoeboid motility. In MyoII essential light chain null cells the polar-force component remained dominant. On the other hand, MyoII heavy chain null cells exhibited a different dominant traction force component, with a marked increase in lateral contractile forces, suggesting that cortical contractility and/or enhanced lateral adhesions are important for motility in this cell line. By compressing the mechanics of chemotaxing cells into a reduced set of temporally-resolved degrees of freedom, the present study may contribute to refined models of cell migration that incorporate cell-substrate interactions

Reinforcement versus Fluidization in Cytoskeletal Mechanoresponsiveness

Every adherent eukaryotic cell exerts appreciable traction forces upon its substrate. Moreover, every resident cell within the heart, great vessels, bladder, gut or lung routinely experiences large periodic stretches. As an acute response to such stretches the cytoskeleton can stiffen, increase traction forces and reinforce, as reported by some, or can soften and fluidize, as reported more recently by our laboratory, but in any given circumstance it remains unknown which response might prevail or why. Using a novel nanotechnology, we show here that in loading conditions expected in most physiological circumstances the localized reinforcement response fails to scale up to the level of homogeneous cell stretch; fluidization trumps reinforcement. Whereas the reinforcement response is known to be mediated by upstream mechanosensing and downstream signaling, results presented here show the fluidization response to be altogether novel: it is a direct physical effect of mechanical force acting upon a structural lattice that is soft and fragile. Cytoskeletal softness and fragility, we argue, is consistent with early evolutionary adaptations of the eukaryotic cell to material properties of a soft inert microenvironment