The Partner Study: Sexual Risks

poster abstractThe Partner Study is a five-year, NIH-Funded research project focused on the potential sexual transmission of HIV from those with the disease to their partners without the disease and on to other sex partners. The project interviewed 114 people with HIV (HIV+), 114 of their sex partners without HIV (HIV-), and also 146 HIV- persons without an HIV+ partner. The project focuses on the reasons why people protect themselves and others. It thus examines such factors as knowledge of HIV, concern about getting or giving the disease, the impact of social norms, partners’ disclosure of HIV status, and ability to communicate with one’s sex partner(s). The findings to be presented include: • A test of the AIDS Risk Reduction Model that is designed to identify the critical factors that determine the activation of a person’s self protection motivation. • An examination of the relevance of social norms to HIV-protection behaviors. Though social scientists have relied on social norms as explanations for behavior since Durkheim, in these findings (1) social norms appear to have a modest effect on behavior even in areas where norms of protection had been thought to be strong and (2) enforcement of social norms is unrelated to eventual behavior. • An examination of multiple reasons people give for using or not using condoms and what those reasons say about their motivations and actual condom use. • An examination of how privacy rules regulate the disclosure of information about HIV to sex partners. Using the Communication Privacy Management perspective (Petronio, 2002), this study examines the privacy boundary surrounding information about HIV status by both the HIV+ partner and the HIV- partner

Staphylococcus aureus intestinal colonization is associated with increased frequency of S. aureus on skin of hospitalized patients

<p>Abstract</p> <p>Background</p> <p>Intestinal colonization by <it>Staphylococcus aureus </it>among hospitalized patients has been associated with increased risk of staphylococcal infection and could potentially contribute to transmission. We hypothesized that <it>S. aureus </it>intestinal colonization is associated with increased frequency of <it>S. aureus </it>on patients' skin and nearby environmental surfaces.</p> <p>Methods</p> <p>Selected inpatients were cultured weekly for <it>S. aureus </it>from stool, nares, skin (groin and axilla), and environmental surfaces (bed rail and bedside table). Investigator's hands were cultured after contacting the patients' skin and the environmental surfaces.</p> <p>Results</p> <p>Of 71 subjects, 32 (45.1%) had negative nares and stool cultures, 23 (32.4%) had positive nares and stool cultures, 13 (18.3%) were nares carriers only, and 3 (4.2%) were stool carriers only. Of the 39 patients with <it>S. aureus </it>carriage, 30 (76.9%) had methicillin-resistant isolates. In comparison to nares colonization only, nares and intestinal colonization was associated with increased frequency of positive skin cultures (41% versus 77%; p = 0.001) and trends toward increased environmental contamination (45% versus 62%; p = 0.188) and acquisition on investigator's hands (36% versus 60%; p = 0.057). Patients with negative nares and stool cultures had low frequency of <it>S. aureus </it>on skin and the environment (4.8% and 11.3%, respectively).</p> <p>Conclusion</p> <p>We found that hospitalized patients with <it>S. aureus </it>nares and/or stool carriage frequently had <it>S. aureus </it>on their skin and on nearby environmental surfaces. <it>S. aureus </it>intestinal colonization was associated with increased frequency of positive skin cultures, which could potentially facilitate staphylococcal infections and nosocomial transmission.</p

Reasons People Give for Using (or not Using) Condoms

Study participants (N = 348) were asked about 46 reasons that have been suggested for why people use or do not use condoms. Participants were asked which of these reasons motivated them when they were deciding whether to use condoms in 503 sexual relationships. Participants were classified into one of three roles based on their HIV status and the status of each sexual partner: HIV+ people with HIV− partners; HIV− people with HIV+ partners; and HIV− people with HIV− partners. Motivations were looked at in the context of each of these roles. Of the 46 reasons, only 15 were selected by at least 1/3 of the participants, and only seven were selected by at least half. Frequently reported reasons primarily concern protecting self and partner from STDs including HIV. Less frequently reported reasons involved social norms, effects of condoms on sex, and concern for the relationship. These findings have implications for clinical interventions

Tailoring an intervention to the context and system redesign related to the intervention: A case study of implementing shared medical appointments for diabetes

<p>Abstract</p> <p>Background</p> <p>Incorporating shared medical appointments (SMAs) or group visits into clinical practice to improve care and increase efficiency has become a popular intervention, but the processes to implement and sustain them have not been well described. The purpose of this study was to describe the process of implementation of SMAs in the local context of a primary care clinic over time.</p> <p>Methods</p> <p>The setting was a primary care clinic of an urban academic medical center of the Veterans Health Administration. We performed an in-depth case analysis utilizing both an innovations framework and a nested systems framework approach. This analysis helped organize and summarize implementation and sustainability issues, specifically: the pre-SMA local context; the processes of tailoring and implementation of the intervention; and the evolution and sustainability of the intervention and its context.</p> <p>Results</p> <p>Both the improvement intervention and the local context co-adapted and evolved during implementation, ensuring sustainability. The most important promoting factors were the formation of a core team committed to quality and improvement, and the clinic leadership that was supported strongly by the team members. Tailoring had to also take into account key innovation-hindering factors, including limited resources (such as space), potential to alter longstanding patient-provider relationships, and organizational silos (disconnected groups) with core team members reporting to different supervisors.</p> <p>Conclusion</p> <p>Although interventions must be designed to meet the needs of the sites in which they are implemented, specific guidance tailored to the practice environment was lacking. SMAs require complex changes that impact on care routines, collaborations, and various organizational levels. Although the SMA was not envisioned originally as a form of system redesign that would alter the context in which it was implemented, it became clear that tailoring the intervention alone would not ensure sustainability, and therefore adjustments to the system were required. The innovation necessitated reconfiguring some aspects of the primary care clinic itself and other services from which the patients and the team were derived. In addition, the relationships among different parts of the system were altered.</p

Explaining Society: An Expanded Toolbox for Social Scientists

We propose for social scientists a theoretical toolbox containing a set of motivations that neurobiologists have recently validated. We show how these motivations can be used to create a theory of society recognizably similar to existing stable societies (sustainable, self-reproducing, and largely peaceful). Using this toolbox, we describe society in terms of three institutions: economy (a source of sustainability), government (peace), and the family (reproducibility). Conducting a thought experiment in three parts, we begin with a simple theory with only two motivations. We then create successive theories that systematically add motivations, showing that each element in the toolbox makes its own contribution to explain the workings of a stable society and that the family has a critical role in this process

Electron-impact excitation cross section for the two lowest triplet states of molecular hydrogen

Calculations for the electron-impact excitation cross sections of molecular hydrogen from its ground (X1Σg+) to its first (b3Σu+) and second (a3Σg+) triplet states were performed using the Ochkur (O) and Ochkur-Rudge (OR) approximations. All nuclear motions were taken into account. It was found that the first triplet cross section is sensitive to the choice of the ground-state wave function whereas the second one is not. The former is also sensitive to the excited-state wave function used. The results using the O approximation are significantly larger than those of the OR approximation, and the maximum cross section occurs at a somewhat lower energy. Use of the separated-atom approximation produced results significantly lower than those arising from inclusion of all the multicenter terms in the scattering amplitude. The sum of the first and second OR triplet cross sections agrees well with a recent approximate experimental determination of the cross section for the electron-impact dissociation of H2 into 2H. More accurate experiments are now needed to further test the OR approximation

Continuous recruitment of naive T cells contributes to heterogeneity of antiviral CD8 T cells during persistent infection

Numerous microbes establish persistent infections, accompanied by antigen-specific CD8 T cell activation. Pathogen-specific T cells in chronically infected hosts are often phenotypically and functionally variable, as well as distinct from T cells responding to nonpersistent infections; this phenotypic heterogeneity has been attributed to an ongoing reencounter with antigen. Paradoxically, maintenance of memory CD8 T cells to acutely resolved infections is antigen independent, whereas there is a dependence on antigen for T cell survival in chronically infected hosts. Using two chronic viral infections, we demonstrate that new naive antigen-specific CD8 T cells are primed after the acute phase of infection. These newly recruited T cells are phenotypically distinct from those primed earlier. Long-lived antiviral CD8 T cells are defective in self-renewal, and lack of thymic output results in the decline of virus-specific CD8 T cells, indicating that newly generated T cells preserve antiviral CD8 T cell populations during chronic infection. These findings reveal a novel role for antigen in maintaining virus-specific CD8 T cells during persistent infection and provide insight toward understanding T cell differentiation in chronic infection

CD11c+ Cells Are Gatekeepers for Lymphocyte Trafficking to Infiltrated Islets During Type 1 Diabetes.

Type 1 diabetes (T1D) is a T cell mediated autoimmune disease that affects more than 19 million people with incidence increasing rapidly worldwide. For T cells to effectively drive T1D, they must first traffic to the islets and extravasate through the islet vasculature. Understanding the cues that lead to T cell entry into inflamed islets is important because diagnosed T1D patients already have established immune infiltration of their islets. Here we show that CD11

Individual rules for trail pattern formation in Argentine ants (Linepithema humile)

We studied the formation of trail patterns by Argentine ants exploring an empty arena. Using a novel imaging and analysis technique we estimated pheromone concentrations at all spatial positions in the experimental arena and at different times. Then we derived the response function of individual ants to pheromone concentrations by looking at correlations between concentrations and changes in speed or direction of the ants. Ants were found to turn in response to local pheromone concentrations, while their speed was largely unaffected by these concentrations. Ants did not integrate pheromone concentrations over time, with the concentration of pheromone in a 1 cm radius in front of the ant determining the turning angle. The response to pheromone was found to follow a Weber's Law, such that the difference between quantities of pheromone on the two sides of the ant divided by their sum determines the magnitude of the turning angle. This proportional response is in apparent contradiction with the well-established non-linear choice function used in the literature to model the results of binary bridge experiments in ant colonies (Deneubourg et al. 1990). However, agent based simulations implementing the Weber's Law response function led to the formation of trails and reproduced results reported in the literature. We show analytically that a sigmoidal response, analogous to that in the classical Deneubourg model for collective decision making, can be derived from the individual Weber-type response to pheromone concentrations that we have established in our experiments when directional noise around the preferred direction of movement of the ants is assumed.Comment: final version, 9 figures, submitted to Plos Computational Biology (accepted