Head Start Teaching Center: Differential Training Effects for Head Start Personnel

Driven by research findings regarding the positive relationship between training and enhancement of services, as well as literature on adult learning, the New England Head Start Teaching Center (NEHSTC) was created in 1992 to test the efficacy of participatory, hands-on training. The purpose of this paper is to examine the outcome evaluation results from 4 years of training at the NEHSTC, 1 of 14 federally funded sites, as well as to discuss the implications for delivering this type of participatory training throughout Head Start. Findings suggest that the NEHSTC was successful in implementing high quality, participatory training within the context of an ongoing Head Start program. Head Start staff who participated in the NEHSTC trainings demonstrated gains in knowledge, skills, and expertise compared to similar Head Start employees who did not receive training. Results also reveal a sustained effect of training over time, with NEHSTC participants continuing to demonstrate enhanced knowledge and skills 6 months after training. Similar positive outcomes of training were found for staff with varying levels of experience and holding different Head Start positions. Thus the participatory, hands-on training implemented by the NEHSTC was found to produce positive and lasting outcomes for diverse Head Start staff. An effective and cost efficient model of training Head Start personnel is particularly relevant and timely as Head Start strives to establish universal quality and expansion of services in the 21st Century. The findings are also relevant for improving the quality of all early care and education programs.     

Competitive binding of 7-substituted-2,3-dichlorodibenzo-p-dioxins with human placental ah receptor--a QSAR analysis

The competitive binding affinities of thirteen 7-substituted-2,3-dichlorodibenzo-p-dioxins to the human placental cytosolic aryl hydrocarbon (Ah) receptor were determined using [3H]2,3,7,8-tetrachlorodibenzo-p-dioxin as the radioligand. Multiple parameter linear regression analysis of the competitive binding C50 values for these compounds gave the following equation: pEC50 (M) = 6.246 + 1.632 pi - 1.764 sigma 0m + 1.282 HB where pi, sigma m and HB are the physiochemical parameters for substituent lipophilicity, meta-directing electronegativity, and hydrogen bonding capacity respectively. The 7-t-butyl- and 7-phenyl-2,3-dichlorodibenzo-p-dioxins were treated as outliers for the derivation of this equation, and these results suggest that only substituents with van der Waals' volumes less than 40 cm3/mol were accommodated in the receptor binding site. The equations previously derived from the binding of the 7-substituted-2,3-dichlorodibenzo-p-dioxins to the rat, mouse, guinea pig, and hamster hepatic cytosolic receptor were different than the correlation obtained using human placental receptor and provide further evidence for the interspecies differences in the molecular and binding properties of the Ah receptor protein.     

Preconditioning-specific reduction of c-fos expression in hippocampal granule and pyramidal but not other forebrain neurons of ischemic brain: a quantitative immunohistochemical study

To specify targets for an ischemic preconditioning paradigm (ischemic tolerance), c-fos expressions in ischemic (induced by 10 min bilateral carotid-occlusions subsequent to coagulation of vertebral arteries) and preconditioned rats (treated for 4 min carotid-occlusions 72 h before ischemia) were compared in 12 forebrain areas/nuclei. Fos immunostaining was applied to serial sections of the forebrain and the density (cell number/area measured) of Fos-immunopositive (Fos+) neurons, as well as their percentile changes were determined in five hippocampal and seven extrahippocampal areas/nuclei of ischemic and preconditioned rats. The ratio of counts found in ischemic over control animals showed several fold increase of Fos+ cells in the three layers (granule cell, molecular and polymorphic) of the dentate gyrus, CA3 and CA1 pyramidal neurons, as well as in thalamic and hypothalamic nuclei and limbic cortical areas. In contrast, preconditioning did not alter c-fos expressions significantly in the extrahippocampal brain areas investigated. These results strengthen the hypothesis that the hippocampal and dentate neurons are more susceptible to ischemic tolerance than cells in other brain regions. In fact stress-response and induction of ischemic tolerance in different forebrain areas can be distinguished.     

Verification of Ir-192 near source dosimetry using GAFCHROMIC film

Intravascular brachytherapy treatments of in-stent restenosis have been performed extensively using Ir-192 ribbon. Task Group 60 of the American Association of Physicists in Medicine (AAPM) recommends a dose reference point at 2 mm from the source center for these treatments. However, it is known that the source can be as close as 0.5 mm to the arterial wall if not centered in the lumen. Therefore, the source dosimetry needs to be characterized at these close distances to accurately determine the amount of dose delivered for noncentered cases. In this paper, we report the verification of the dose distributions around Ir-192 seed sources at radial distances from 0.5 mm to 6 mm using GAFCHROMIC film. We evaluated an Ir-192 single seed source and a train of 6 seeds spaced 1 mm apart enclosed in a nylon ribbon. Each source was placed in a homogeneous solid water phantom directly below a stack of GAFCHROMIC films (MD-55-2). The calibration curve of the lot of films used in the experiment was established for Ir-192 by exposing a set of calibration films, one at a time, to an Ir-192 high dose rate (HDR) source. All films were scanned 5 or more days after exposure with a Lumisys Model 150 microdensitometer. The data were acquired and evaluated using RIT113 (Radiological Imaging Technology) software and analyzed using Excel and IDL (Interactive Data Language) software. Isodose curve plots in the plane containing the source's longitudinal axis and dose rate plots in the radial direction were obtained. For both configurations, the dose rates along the transverse axes agree to within the margin of error with previous Monte Carlo results. The isodose curve plots display hot spots near the seed ends, which is consistent with the leakage of beta particles and electrons from the unsealed seed ends as predicted with Monte Carlo calculations.     

Ah receptor in human placenta: stabilization by molybdate and characterization of binding of 2,3,7,8-tetrachlorodibenzo-p-dioxin, 3-methylcholanthrene, and benzo(a)pyrene

Aryl hydrocarbon hydroxylase (AHH, cytochrome P1-450) is highly inducible in several human cells and tissues exposed to specific halogenated and nonhalogenated aromatic chemicals of the "3-methylcholanthrene-type." In laboratory animals AHH induction is known to be regulated by binding of inducers to the Ah receptor, a soluble intracellular protein. However, the induction mechanism in the human species is incompletely understood largely because the Ah receptor, which seems to be essential to the induction process, has not previously been detectable in certain human cells and tissues (including placenta) that are highly responsive to AHH induction. We found that human placenta contains high concentrations of Ah receptor (comparable to the receptor concentrations in rat and mouse liver) but that special modifications were necessary in the assay techniques in order to detect and accurately quantitate receptor binding. Receptor was detected at concentrations approximately equal to 100 fmol/mg cytosol protein using [3H]2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as the radioligand. This high concentration of specific binding sites was present only if the placental tissue was initially homogenized in a buffer containing sodium molybdate (10 or 20 mM). Without molybdate in the homogenizing buffer, specific [3H]TCDD binding was only about 35 fmol/mg. Specific Ah receptor binding also was detectable with [3H]-3-methylcholanthrene and, to a lesser extent, with [3H]-benzo(alpha)pyrene. The receptor sedimented near 9S on sucrose gradients whether molybdate was present or not. About 80% of specific binding was lost if excessive charcoal was used to adsorb "nonspecifically bound" ligand from cytosol prior to gradient analyses. The apparent affinity with which [3H]TCDD bound to Ah receptor in human placental cytosol was relatively low (apparent Kd approximately equal to 5 to 8 nM) when compared with the affinity of [3H]TCDD binding in rat or mouse hepatic cytosols (Kd approximately equal to 1 to 3 nM). These data suggest that while molybdate has very little effect on the quantity or molecular size of the rodent Ah receptor assay, it is very important in stabilizing the human Ah receptor. Our experiments demonstrate that human placenta contains a high concentration of Ah receptor and suggest that AHH induction in placenta is mediated through a receptor mechanism analogous to that previously established in tissues and cells from laboratory animals.     

Multiple Dimensions of Peer Influence in Adolescent Romantic and Sexual Relationships: A Descriptive,Qualitative Perspective

Archives of Sexual Behavior - Adolescents undergo critical developmental transformations that increase the salience of peer influence. Peer interactions (platonic and romantic) have been found to...     

Methods of using interleukin 2 to enhance HIV-specific immune responses

Interleukin 2 (IL-2) in combination with highly active antiretroviral therapy (HAART) can significantly increase CD4+ T cell counts but does not improve HIV-specific T cell-mediated immune responses that are associated with the control of viral replication. To characterize the immunomodulatory activity of IL-2 in HIV-infected individuals we studied the virus-specific immune response (VIR) by intracellular cytokine expression (interferon gamma, IFN-gamma) after mimicking HIV rebound in peripheral blood mononuclear cells (PBMCs). We found that the whole virus used as HIV antigen was able to activate HIV-specific T cells in the presence of a low concentration (50 IU/ml) of IL-2. Interestingly, increasing concentrations of IL-2 (400 or 1000 IU/ml) in combination with the same amount of HIV doubled the number of HIV-specific T cells. These cells were functionally intact because all of the IFN-gamma-producing CD8+ T cells contained perforin, a marker for cytotoxic T lymphocytes (CTLs). Induction of HIV-specific immune responses by IL-2 was not detected in the absence of HIV antigen both in vitro and in patients treated with HAART, indicating that IL-2 can amplify HIV-specific T cells in the presence of HIV antigen. Therefore, a combination of IL-2 with either structured treatment interruption, which results in a controlled viral load rebound, or with therapeutic vaccination is expected to improve HIV-specific T cell-mediated immune responses.     

Perennial grasslands enhance biodiversity and multiple ecosystem services in bioenergy landscapes

Agriculture is being challenged to provide food, and increasingly fuel, for an expanding global population. Producing bioenergy crops on marginal lands—farmland suboptimal for food crops—could help meet energy goals while minimizing competition with food production. However, the ecological costs and benefits of growing bioenergy feedstocks—primarily annual grain crops—on marginal lands have been questioned. Here we show that perennial bioenergy crops provide an alternative to annual grains that increases biodiversity of multiple taxa and sustain a variety of ecosystem functions, promoting the creation of multifunctional agricultural landscapes. We found that switchgrass and prairie plantings harbored significantly greater plant, methanotrophic bacteria, arthropod, and bird diversity than maize. Although biomass production was greater in maize, all other ecosystem services, including methane consumption, pest suppression, pollination, and conservation of grassland birds, were higher in perennial grasslands. Moreover, we found that the linkage between biodiversity and ecosystem services is dependent not only on the choice of bioenergy crop but also on its location relative to other habitats, with local landscape context as important as crop choice in determining provision of some services. Our study suggests that bioenergy policy that supports coordinated land use can diversify agricultural landscapes and sustain multiple critical ecosystem services.In agricultural landscapes, balancing the provisioning of food and energy with maintenance of biodiversity and ecosystem functions is a global challenge. To avoid impacts on food production, attention is increasingly being focused on the potential for marginal lands to support bioenergy production (1). Marginal lands, those suboptimal for food production, may consist of relatively small areas within generally productive landscapes or larger regions where conditions generally limit crop productivity. However, there is increasing recognition that these lands are already performing a variety of useful functions, and their conversion to bioenergy cropping could reduce these services. For example, in the north central United States, rising commodity prices are predicted to bring marginal croplands—including Conservation Reserve Program lands—into annual crop production with negative impacts on wildlife habitat and water quality (2, 3). With 2013 corn plantings at recent record highs (4) and new reports of grassland and wetland conversion to cropland (5, 6), this may be occurring already.An alternative to annual cropping is conversion of marginal croplands to perennial, cellulosic crops for bioenergy. Although current US biofuel production centers on grain ethanol derived from annual monocultures of maize (Zea mays), this situation could change with full implementation of the 2007 US Energy Independence and Security Act (7), which calls for increased production of cellulosic biofuels. In the Midwest United States, perennial grasses and forbs grown on marginal lands could provide up to 25% of national targets for cellulosic biofuel, with substantial greenhouse gas (GHG) benefits (8). Moreover, increasing the area of perennial cover on the landscape is predicted to positively affect a diverse array of organisms and ecological functions (9–11), leading to important synergies that have not yet informed the ongoing bioenergy debate. Here we provide the most comprehensive empirical evaluation of this hypothesis to date, reporting data that elucidate the impacts of different bioenergy cropping systems on a wide variety of organisms and the ecosystem functions they perform.Previous studies have examined the ability of select bioenergy crops to support specific taxa (12) or individual services such as energy production (13) or GHG mitigation (14), without consideration of the tradeoffs or synergies that can arise when considering entire suites of organisms and ecosystem functions. We report on a unique multidisciplinary study of matched sets of organisms and ecosystem services and show that perennial grass energy crops (switchgrass, Panicum virgatum, and mixed prairie plantings) synergistically enhance diversity of a variety of organisms and levels of the services they provide. We further quantify the importance of landscape context on service provisioning, suggesting that policy supporting intentional design of bioenergy landscapes could increase sustainability of both food and energy production.     

HIV-1 prophylactic vaccine comprised of topical DermaVir prime and protein boost elicits cellular immune responses and controls pathogenic R5 SHIV162P3

Topical DNA vaccination (DermaVir) facilitates antigen presentation to naive T cells. DermaVir immunization in mice, using HIV-1 Env and Gag, elicited cellular immune responses. Boosting with HIV-1 gp120 Env and p41 Gag augmented Th1 cytokine levels. Intramuscular DNA administration was less efficient in priming antigen-specific cytokine production and memory T cells. In rhesus macaques, DermaVir immunization induced Gag- and Env-specific Th1 and Th2 cytokines and generation of memory T cells. Boosting of DermaVir-primed serum antibody levels was noted following gp140(SHIV89.6P)/p27(SIV) immunization. Rectal challenge with pathogenic R5-tropic SHIV162P3 resulted in control of plasma viremia (4/5 animals) that was reflected in jejunum, colon and mesenteric lymph nodes. An inverse correlation was found between Gag- and Env-specific central memory T cell responses on the day of challenge and plasma viremia at set point. Overall, the topical DermaVir/protein vaccination yields central memory T cell responses and facilitates control of pathogenic SHIV infection.