TRAJECTORIES OF SCHOOL AND COMMUNITY CONNECTEDNESS IN ADOLESCENCE BY GENDER AND DELINQUENT BEHAVIOR

Previous studies suggest that both school and community connectedness among adolescents are associated with prosocial behaviors and positive outcomes. While delinquency is associated with lack of connectedness to school and community, little research has considered how delinquency affects this relationship for adolescents living in impoverished neighborhoods. This study estimated gendered trajectories of school and community connectedness for adolescents in impoverished neighborhoods as a function of their levels of delinquency. Results showed that delinquency was negatively correlated and that age was positively correlated with school connectedness for both genders. In contrast, community connectedness increased with age for boys, but decreased with age for girls. In addition, delinquency was negatively related to community connectedness for boys, but not for girls. These findings suggest that for adolescents in impoverished neighborhoods, gender‐informed interventions to decrease delinquency could have positive effects on school and community connectedness.     

Effect of early exposure on the integration of dental implants in the baboon: Part 1--Clinical findings at uncovering

There has been increased discussion on the advantages of a one- versus a two-stage surgical approach in the placement of dental endosseous implants. This study evaluated the influence of early implant exposure on crestal bone height adjacent to the implant surface and Periotest values at uncovering in the baboon. Forty-eight implants (24 commercially pure titanium, 24 titanium alloy) were placed in maxillary and mandibular posterior sites in 6 baboons. Implant exposure was evaluated weekly for 3 weeks after implant placement. The level of bone adjacent to the dental implants was measured at placement from the top of the implant collar to the crest of the bone at the mesial, distal, buccal, and lingual surfaces. The maxillary sites were measured again at a 6-month uncovering, while the mandibular sites were measured at a 3-month uncovering. Periotest readings were also recorded at uncovering. Early implant exposure was more common in the mandible, with the majority occurring by the second week postplacement. There were no significant differences in the crestal bone height changes at uncovering between the pure titanium and alloy implants in either arch. In the maxilla, the changes in crestal bone height were not statistically different between exposed and nonexposed implants at any aspect. In the mandible, the difference in 3-month changes between exposed and nonexposed implants was significant for the distal, buccal, and lingual aspects. The overall percentage of implants with a Periotest reading in the "good" category was greater for the nonexposed sites as compared to exposed sites. The results of this study suggest that the two-stage surgical approach results in a better clinical outcome as compared to the one-stage approach in the baboon model.     

The effects of victimization on drug use: a multilevel analysis

Agnew's general strain theory suggests that negative life experiences constitute stress that may lead to deviance, unless effective coping strategies are forthcoming. In the present study, the principles of general strain theory were employed to examine the age-varying effects of three types of victimization on drug-using behavior: sexual victimization, physical victimization, or other victimization. Study data came from seven waves of the National Youth Survey, a longitudinal survey of youth ages 11 to 17 years when the study began in 1976. The broad hypotheses of general strain theory were supported, by the data, with some qualifications. Results of the data analysis also showed that victimization's impact on drug use is type-specific and/or drug-specific. Further studies with more sophisticated measures of drug use should clarify the role of victimization (by type) in various drug-using behaviors. The study's limitations are noted.     

Excess and deficient omega-3 fatty acid during pregnancy and lactation cause impaired neural transmission in rat pups

Omega-3 fatty acids (ω-3 FA) consumption during pregnancy and lactation is beneficial to fetal and infant growth and may reduce the severity of preterm births. Thus, scientists and clinicians are recommending increasingly higher ω-3 FA doses for pregnant women and nursing babies for advancing the health of preterm, low birth weight, and normal babies. In contrast, some studies report that over-supplementation with ω-3 FA can have adverse effects on fetal and infant development by causing a form of nutritional toxicity. Our goal was to assess the effects of ω-3 FA excess and deficiency during pregnancy and lactation on the offspring's neural transmission as evidenced by their auditory brainstem responses (ABR). Female Wistar rats were given one of three diets from day 1 of pregnancy through lactation. The three diets were the Control ω-3 FA condition (ω-3/ω-6 ratio  0.14), the Deficient ω-3 FA condition (ω-3/ω-6 ratio  0%) and the Excess ω-3 FA condition (ω-3/ω-6 ratio  14.0). The Control diet contained 7% soybean oil, whereas the Deficient diet contained 7% safflower oil and the Excess diet contained 7% fish oil. The offspring were ABR-tested on postnatal day 24. The rat pups in the Excess group had prolonged ABR latencies in comparison to the Control group, indicating slowed neural transmission times. The pups in the Excess group also showed postnatal growth restriction. The Deficient group showed adverse effects that were milder than those seen in the Excess group. Milk fatty acid profiles reflected the fatty acid profiles of the maternal diets. In conclusion, excess or deficient amounts of ω-3 FA during pregnancy and lactation adversely affected the offspring's neural transmission times and postnatal thriving. Consuming either large or inadequate amounts of ω-3 FA during pregnancy and lactation seems inadvisable because of the potential for adverse effects on infant development.     

Nevirapine resistance in women and infants after first versus repeated use of single-dose nevirapine for prevention of HIV-1 vertical transmission

Single-dose (SD) nevirapine (NVP) significantly reduces mother-to-child transmission of human immunodeficiency virus (HIV). We analyzed NVP resistance after receipt of SD NVP in 57 previously SD NVP-naive women, in 34 SD NVP-experienced women, and in 17 HIV-infected infants. The proportion of women infected with variants with resistance mutations, the types of mutations detected, and the frequency and level of K103N were similar in the two groups of women at 6 weeks and 6 months post partum. NVP resistance was detected in a similar proportion of infants born to SD NVP-naive versus SD NVP-experienced women. Repeated use of SD NVP to prevent HIV transmission does not appear to influence NVP resistance.     

Characterizing potential exposure to the public from low-level radioactive waste transportation by truck

To address public concern about potential exposure to gamma radiation from legal-weight low-level radioactive waste truck shipments to the Nevada Test Site, a stationary, automated array of four pressurized ion chambers was established for trucks to pass through. Data were collected from 1,012 of the 2,260 trucks that transported low-level radioactive waste to the Nevada Test Site from February through December 2003. To avoid perception of biasing a potential exposure low, the maximum reading (muR per hour; muR h(-1)) from the array was assigned as the gross measurement value for each truck. [In this article, exposure measurements are reported as Roentgen (R), as this unit is consistent with the data readings of the measurement instruments and has been historically presented to public stakeholders. Subsequently, dose measurements are reported as Roentgen Equivalent Man (rem).] To calculate the "net exposure" for each truck, the average and standard deviation of the maximum background values during the corresponding 12-h period when the truck arrived were subtracted from the gross value. For 483 trucks (47.7%), calculated net exposure values were equal to or less than zero, indicating that the exposure from the truck was indistinguishable from background. An additional 206 trucks (20.4%) had calculated net exposure values ranging between 0.0 and 1.0 muR h(-1). Cumulative exposure scenarios appropriate for rural transportation routes to the Nevada Test Site were developed; however, these scenarios assumed the unlikely case that the same individual was exposed to all of the trucks on that route. Cumulative exposure values were dominated by a small percentage of the trucks with comparatively high values. In communities along transportation routes, the probability of an individual receiving a potential exposure from a single truck may be a more meaningful perspective.