Bogotá

Objetivo: Redefinir el concepto de comportamiento homosexual analizando sus bases apetitivas, precopulatorias, consumatorias y posconsumatorias; así como analizar las bases neurales y el papel del aprendizaje en el comportamiento homosexual. Desarrollo: Proponemos un continuum comportamental con el cual los humanos y animales muestran comportamientos homosexuales de expresión y duración variable. Se discute el papel del dimorfismo sexual del cerebro y la evidencia que lo correlaciona con el comportamiento y las preferencias sexuales. También se muestra evidencia reciente que sugiere que a través del condicionamiento, los animales pueden desplegar preferencias que pasan de lo social a lo homosexual de manera temporal si pasaron suficiente tiempo junto a la pareja del mismo sexo, bajo la influencia de agonistas para el receptor de dopamina tipo D2. Conclusión: la discusión en este artículo sugiere que el comportamiento homosexual puede ocurrir de manera sutil o explícita, temporal o permanentemente, dependiendo del cálculo que resulta de la actividad de neurocircuitos organizados por hormonas en periodos perinatales junto con aquellos circuitos organizados por el aprendizaje en periodos posteriores.

BACKGROUND Poor communication between referring clinicians and specialists may lead to inefficient use of specialist services. San Francisco General Hospital implemented an electronic referral system (eReferral) that facilitates iterative pre-visit communication between referring and specialty clinicians to improve the referral process. OBJECTIVE The purpose of the study was to determine the impact of eReferral (compared with paper-based referrals) on specialty referrals. DESIGN The study was based on a visit-based questionnaire appended to new patient charts at randomly selected specialist clinic sessions before and after the implementation of eReferral. PARTICIPANTS Specialty clinicians. MAIN MEASURES The questionnaire focused on the self-reported difficulty in identifying referral question, referral appropriateness, need for and avoidability of follow-up visits. KEY RESULTS We collected 505 questionnaires from speciality clinicians. It was difficult to identify the reason for referral in 19.8% of medical and 38.0% of surgical visits using paper-based methods vs. 11.0% and 9.5% of those using eReferral (p-value 0.03 and <0.001). Of those using eReferral, 6.4% and 9.8% of medical and surgical referrals using paper methods vs. 2.6% and 2.1% were deemed not completely appropriate (p-value 0.21 and 0.03). Follow-up was requested for 82.4% and 76.2% of medical and surgical patients with paper-based referrals vs. 90.1% and 58.1% of eReferrals (p-value 0.06 and 0.01). Follow-up was considered avoidable for 32.4% and 44.7% of medical and surgical follow-ups with paper-based methods vs. 27.5% and 13.5% with eReferral (0.41 and <0.001). CONCLUSION Use of technology to promote standardized referral processes and iterative communication between referring clinicians and specialists has the potential to improve communication between primary care providers and specialists and to increase the effectiveness of specialty referrals.

BACKGROUND Interpersonal trust plays an important role in the clinic visit. Clinician trust in the patient may be especially important when prescribing opioid analgesics because of concerns about misuse. Previous studies have found that non-white patients are perceived negatively by clinicians. OBJECTIVE To examine whether clinicians’ trust in patients differed by patients’ race/ethnicity in a socially marginalized cohort. DESIGN Cross-sectional study of patient-clinician dyads. PARTICIPANTS 169 HIV infected indigent patients recruited from the community and their 61 primary care providers (PCPs.) MAIN MEASURES The Physician Trust in Patients Scale (PTPS), a validated scale that measures PCPs’ trust in patients. KEY RESULTS The mean PTPS score was 43.2 (SD 10.8) out of a possible 60. Reported current illicit drug use and prescription opioid misuse were similar across patients’ race or ethnicity. However, both patient illicit drug use and patient non-white race/ethnicity were associated with lower PTPS scores. In a multivariate model, non-white race/ethnicity was independently associated with PTPS scores 6.3 points lower than whites (95% CI: −9.9, −2.7). Current illicit drug use was associated with PTSP scores 5.5 lower than no drug use (95% CI −8.5, −2.5). CONCLUSION In a socially marginalized cohort, non-white patients were trusted less than white patients by their PCPs, despite similar rates of illicit drug use and opioid analgesic misuse. The effect was independent of illicit drug use. This finding may reflect unconscious stereotypes by PCPs and may underlie disparities in chronic pain management.

To assess the association between antiretroviral therapy (ART) and fertility history and desire among HIV-positive Ugandan women, we conducted a cross-sectional study among HIV-positive Ugandan women aged 18–50 years who attended an HIV clinic at Mbarara University in western Uganda between November 1, 2005 and June 6, 2006. Of 538 women approached, 501 were enrolled. ART use was associated with increased odds of fertility desire (AOR 2.99, 95% CI 1.38–6.28), and decreased odds of pregnancy (AOR 0.56, 95% CI 0.33–0.95) and live birth (AOR 0.30, 95% CI 0.13–0.66). ART was associated with an increase in fertility desire, but was not associated with an increase in fertility. Additional studies will be needed to determine if this greater fertility desire among ART-treated women leads to an increase in fertility as ART use expands.

Mortality has declined in most HIV-infected populations yet remains high among those with barriers to accessing antiretroviral (ARV) therapy. We sought to determine predictors of death in a group of HIV-infected homeless persons in San Francisco. Between 1996 and 2002, quarterly interviews and blood draws were conducted. Hazards of death were compared by number of months of the prior 6 months that an individual took any ARV, drug use, hepatitis C virus (HCV) status, and housing status. Among 330 participants, 65% were HCV-seropositive at baseline, 85% received ARV during the study period, and there were 57 deaths (5.3 per 100 person-years). Compared with 0 of the prior 6 months on therapy, the risk of death was not significantly reduced for individuals on 1 to 5 months of therapy (hazard ratio [HR] = 0.82, 95% confidence interval [CI]: 0.43-1.57), but the risk of death was reduced 62% for those on ARV therapy for 6 months (HR = 0.38, CI: 0.19-0.76). Housing status and HCV status were not significant predictors of death. HIV is the major cause of death in this population, whereas the impact of HCV infection seems to be minimal. Sustained ARV treatment significantly reduces the risk of death among the homeless.

Background: While the relationship between average adherence to HIV potent antiretroviral therapy is well defined, the relationship between patterns of adherence within adherence strata has not been investigated. We examined medication event monitoring system (MEMS) defined adherence patterns and their relation to subsequent virologic rebound.

While the majority of medical inpatients in Uganda are assumed to be HIV-positive, HIV testing is limited in inpatient settings. This study describes HIV testing practices and risk behavior among medical inpatients at an urban hospital in Uganda. We interviewed 395 adults on the day of discharge. Overall, 46% tested for HIV before or during admission. Of the 20% tested during hospitalization, 64% were HIV-positive. Among 47% who had sex in the previous year, only 14% used condoms consistently and only 20% knew the HIV status of their sexual partner, indicating that participants would benefit from risk-reduction counseling. Yet, only 26% of participants tested during hospitalization received post-test counseling. Half of the participants with HIV-related illnesses left the hospital without being offered the test, a missed opportunity for HIV prevention counseling and care. The findings indicate that hospitals are important venues for HIV counseling and testing.

Objective: To determine the prevalence of depressive disorder in patients with HIV/AIDS receiving HAART; to determine the effect of depressive disorder on adherence to antiretroviral therapy; and to determine the significance of the association. Method: The study was conducted amongst outpatients of Ahmadu Bello University Teaching Hospital, Zaria. A sociodemographic and drug adherence questionnaire was administered. The Centre for Epidemiological Studies Depression Scale (CES-D) was used to screen for depressive symptoms while the Schedule for Clinical Assessment in Neuropsychiatry (SCAN) was used to confirm the diagnosis of depressive disorder. Results: A total of 310 patients with HIV/AIDS receiving HAART participated in the study. 68.4% were female and the mean age was 35.5 (± 8.97 years). 37.4% had secondary education, while 27.1% had tertiary education. Sixty-six participants (21.3%) had significant depressive symptoms while 14.2% met ICD-10 diagnostic criteria for depressive disorder. Overall, 73% of participants had good adherence to HAART. 63.6% of participants with depressive disorder had poor adherence to HAART compared to 21.1% of participants without depressive disorder (p<0.05). Conclusion: Depressive disorder in patients with HIV/AIDS is associated with poor adherence to antiretroviral medication. Early identification and treatment of depression in such patients may improve antiretroviral medication adherence and treatment outcomes.

This paper presents the results of recent flight tests of several anti-windup (AW) compensators on the German Aerospace Centre's (DLR) Advanced Technologies Testing Aircraft (ATTAS). The objectives of the tests were twofold: to demonstrate the potential for rigorously designed low order AW compensators to reduce the pilot-involved-oscillation (PIO) proneness of the aircraft and improve the handling qualities; and to compare a variety of low-order AW compensators to determine the importance of different design parameters. The AW compensators were assessed based on pilot handling qualities ratings (HQRs) and PIO ratings (PIORs). These ratings, and supporting pilot comments and flight data, demonstrate that the AW compensators improved the handling qualities and reduced the PIO proneness of the aircraft, albeit to different degrees. The results also provide a basic understanding of the relationship between design parameters and the response of the piloted aircraft during periods of rate saturation.

This paper presents the application of a rate saturation compensation scheme to the DLR Advanced Technologies Testing Aircraft (ATTAS) and the results of the subsequent flight tests. Details of the design philosophy and the flight tests, termed SAIFE (Saturation Alleviation In-Flight Experiment), which employed the HQDT (Handling Qualities During Tracking) test technique, are presented, as well as pilot flight test reports (PFRs). The rate saturation compensators were designed based on the anti-windup (AW) control philosophy, with the aim to reduce the deleterious effects of rate saturation on the piloted aircraft dynamics, and hence provide an increased flight envelope (operating envelope) for acceptable aircraft handling qualities and reduced PIO (Pilot-in-the-Loop/Pilot-involved Oscillation) tendencies. The achievement of this goal was primarily determined by subjective pilot handling qualities ratings and PIO ratings, and secondly by supporting flight test data. The results show that the compensation scheme greatly reduced the level of rate saturation in all instances (flight conditions), making the aircraft less PIO prone in almost all investigated cases, while exhibiting either unchanged or improved handling qualities. Most notably, the flight tests demonstrated the definite potential for well designed AW compensators to improve the safety and handling qualities of aircraft during rate saturation, with some flight conditions exhibiting dramatic improvements.

The aim of this paper is to give a novel solution to the full order anti-windup (AW) compensation problem. The main contribution of the procedure proposed is the reduction of the LMI optimisation problem that has generally been solved, to that of solving a single Riccati equation. This yields a bounded-real Riccati equation where the best performance is given by the infinity norm of the open-loop plant. This new formulation is obtained by completing the square and the synthesis method yields a compensator with two free parameters, simplifying the task of the designer to that of choosing appropriate weights. The results presented here are believed to be more intuitive, taking full adavantage of the free parameters and therefore valuable for engineering applications. Copyright IFAC 2005

This paper develops an anti-windup scheme for systems with rate-limited actuators. The main results show how a full-order anti-windup compensator can be synthesised using an algebraic Riccati equation and several free parameters. A further result then shows how the free parameters may be chosen to influence, in an intuitive way, the local L 2 gain of the system and the size of the region of attraction. The results are of interest due to their low computational burden and hence their applicability to systems of large state dimension.