School Effects on the Wellbeing of Children and Adolescents

Well-being is a multidimensional construct, with psychological, physical and social components. As theoretical basis to help understand this concept and how it relates to school, we propose the Self-Determination Theory, which contends that self-determined motivation and personality integration, growth and well-being are dependent on a healthy balance of three innate psychological needs of autonomy, relatedness and competence. Thus, current indicators involve school effects on children’s well-being, in many diverse modalities which have been explored. Some are described in this chapter, mainly: the importance of peer relationships; the benefits of friendship; the effects of schools in conjunction with some forms of family influence; the school climate in terms of safety and physical ecology; the relevance of the teacher input; the school goal structure and the implementation of cooperative learning. All these parameters have an influence in promoting optimal functioning among children and increasing their well-being by meeting the above mentioned needs. The empirical support for the importance of schools indicates significant small effects, which often translate into important real-life effects as it is admitted at present. The conclusion is that schools do make a difference in children’s peer relationships and well-being

The HIV-1 transmission bottleneck

It is well established that most new systemic infections of HIV-1 can be traced back to one or a limited number of founder viruses. Usually, these founders are more closely related to minor HIV-1 populations in the blood of the presumed donor than to more abundant lineages. This has led to the widely accepted idea that transmission selects for viral characteristics that facilitate crossing the mucosal barrier of the recipient’s genital tract, although the specific selective forces or advantages are not completely defined. However, there are other steps along the way to becoming a founder virus at which selection may occur. These steps include the transition from the donor’s general circulation to the genital tract compartment, survival within the transmission fluid, and establishment of a nascent stable local infection in the recipient’s genital tract. Finally, there is the possibility that important narrowing events may also occur during establishment of systemic infection. This is suggested by the surprising observation that the number of founder viruses detected after transmission in intravenous drug users is also limited. Although some of these steps may be heavily selective, others may result mostly in a stochastic narrowing of the available founder pool. Collectively, they shape the initial infection in each recipient

Protective Mechanisms for Depression among Racial/Ethnic Minority Youth: Empirical Findings, Issues, and Recommendations

We (1) review empirical studies that report findings regarding putative protective mechanisms when exposed to risk of depression in African American and Hispanic adolescents; (2) identify key protective mechanisms for different risk contexts that garner empirical support; (3) synthesize the mechanisms identified as protective against depression among racial/ethnic minority adolescents; and (4) discuss improved methods for advancing understanding of resilience against depression in minority youth. The studies were selected from PsycINFO searches that met the following inclusion criteria: participants between 12 and 21 years of age, inclusions of racial/ethnic minority members, examining protection through an interaction with a risk factor, and outcome measures of depression, depressed mood, or depressive symptomatology. We found 39 eligible studies; 13 of which included multiple racial/ethnic groups. The following were supported as protective mechanisms, at least preliminarily, for at least one racial/ethnic group and in at least one risk context: employment, extracurricular activities, father–adolescent closeness, familism, maternal support, attending predominately minority schools, neighborhood composition, non-parent support, parental inductive reasoning, religiosity, self-esteem, social activities, and positive early teacher relationships. To investigate protective mechanisms more comprehensively and accurately across individual, social, and community levels of influence, we recommend incorporating multilevel modeling or multilevel growth curve analyses and large diverse samples

Relationship between fractional calcium absorption and gastric emptying

The relationship between calcium absorption and gastric emptying and the precision of measurement of fractional calcium absorption using a single isotope technique were evaluated in 14 normal postmenopausal women (age range 61–72 years). On two occasions separated by between 5 and 15 days, each subject was given 250 mL water containing 0.2 MBq of 45Ca in 20 mg of calcium carrier as the chloride, 20 mg kg-1 paracetamol and 9 MBq of 99mTc sulphur colloid. Venous blood samples were taken at -2, 15, 30, 45, 60, 90, 120, 150 and 180 min after consumption of the drink, and gastric emptying (GE) was monitored with a gamma camera. Fractional calcium absorption in the first hour (α6) was calculated from the blood samples obtained at 15, 30, 45, 60, 90 and 120 min. An absorption rate was also derived from the 60 min sample using only a calibration curve (α1). There were close correlations between radiocalcium absorption on the two study days (r= 0.89, P < 0.001 for both α1 and α6) and between α1 and α6 (r= 0.93, P < 0.001). Plasma paracetamol concentrations at 15 min were directly related to the early phase of GE (r= 0.42, P < 0.05). In contrast, calcium absorption was inversely related to GE (r— 0.45, P < 0.05). We conclude that radiocalcium absorption is not greatly influenced by gastric emptying rate and that the single blood sample procedure has similar precision to the six-blood sample test.J. M. Wishart, M. Horowitz, H. A. Morris, A. G. Need, A. Russo, K. L. Jones, W. M. Sun And B. E. C. Nordi