AIDS in rural Africa: a paradigm for HIV-1 prevention

Networks of concurrent sexual partnerships may be the primary cause of epidemic spread of HIV-1 in parts of sub-Saharan Africa. This pattern of sexual behaviour increases the likelihood that individuals experiencing primary HIV-1 infection transmit the virus to other persons. Networks of concurrent partnerships are likely to be important in both the early ('epidemic') and late ('endemic') phases of HIV-1 transmission. Interventions should aim to break the sexual networks, whatever the stage of the epidemic. However, prevention of transmission in the endemic phase also requires a greater awareness of early clinical manifestations of HIV-1 infection in the general population. Such awareness, coupled with the availability of condoms and access to HIV-1 testing facilities, may reduce transmission in discordant couples.     

Sexual histories, partnerships and networks associated with the transmission of gonorrhoea

We aimed to describe and compare sexual links among people with gonorrhoea, by studying patients in 2 UK departments of genitourinary medicine. Interviews were completed for 510 and 235 cases in London and Sheffield respectively. There was a greater proportion of cases in men, homosexual men, non-white and non-British people and fewer female sex workers in London. Total networks of 1738 people in London and 570 people in Sheffield were described. Large linked heterosexual networks identified in Sheffield were associated with local contact, including men with higher numbers of sexual partners. Condom use for vaginal sex was reported for 11% of heterosexual partnerships in Sheffield, and 27% in London, with little difference between regular and casual partners. It was more difficult to define networks in London due to a high proportion of relatively anonymous contacts. These difficulties suggest that research and interventions may profitably focus upon venues for meeting partners as well as partner notification.     

The core group revisited: the effect of partner mixing and migration on the spread of gonorrhea, Chlamydia, and HIV

A set of differential equations are used to model the spread of sexually transmitted diseases (STDs) in a one-sex population that includes a core group of highly sexually active subjects. The effects of partner mixing between groups and migration to and from the core on the equilibrium number of infected are shown for gonorrhea, chlamydia, and HIV. The STDs are described by the transmission probability per sexual contact and the duration of infectiousness. Partner change and intercourse frequencies are estimated from sexual survey data on heterosexual behavior. The core group is small (3% of the total population) with a partner change frequency 15 times and an intercourse frequency 2 times that of the remaining population. The degree of partner mixing and migration between the two groups can be varied. The number of sexual contacts in the three types of partnerships (core-core, "mixed," remaining population-remaining population) is also modeled. The mixed partnerships are assumed to be casual and to have a low frequency of intercourse. The model is fairly simple, and the emphasis is on qualitative rather that predictive results. The effects of partner mixing are found to be strikingly different for gonorrhea, chlamydia, and HIV. With increasing partner mixing between groups, gonorrhea shows a small increase and then a decrease in the total number of infected, whereas chlamydial infection shows a strong increase. For HIV infection the effect depends on the transmission probability; when it is 0.001 per sexual contact, the number of infected with HIV is almost unaffected by the partner mixing, and when the transmission probability is 0.002 per sexual contact, there is a strong increase in the number of HIV infected with increasing partner mixing. The effects of migration are also different for each disease. With increasing migration between groups, gonorrhea is almost unaffected in the total number of infected, whereas chlamydial infection shows a strong increase. For HIV the effect again depends on the transmission probability; when it is 0.001 per sexual contact, the number of infected with HIV shows a strong decrease, and when the transmission probability is 0.002 per sexual contact the number of HIV infected reaches its maximum for medium strong migration. A sensitivity analysis shows that for all three diseases the basic reproductive ratios (R0) and the total number of infected are sensitive to duration of infectiousness. In addition, for gonorrhea and chlamydia, RO is sensitive to the partner change rates in the core, whereas for HIV, RO is sensitive to the frequency of intercourse in the core.(ABSTRACT TRUNCATED AT 400 WORDS)     

Improvements in partner support predict sexual satisfaction among individuals with multiple sclerosis.

Purpose: Sexual dysfunction and low sexual satisfaction are common among individuals with multiple sclerosis (MS); however, little is known about factors that influence sexual satisfaction within this population. As such, the purpose of this study was to investigate the extent to which changes in negative and positive partner support predict sexual satisfaction levels over time in individuals with MS. Design: Eighty-one individuals with MS completed measures of sexual dysfunction, sexual satisfaction, partner social support, and depression. Data from baseline and posttreatment follow-up were obtained from a larger randomized clinical trial of telephone-administered psychotherapy for depression in a population with MS. Multiple regression analyses were conducted with change in overall sexual satisfaction from baseline to posttreatment as the outcome variable. Results: After controlling for age, gender, sexual dysfunction, years diagnosed with MS, and depression severity, those with increased positive partner support reported significant improvement in sexual satisfaction over time (β = .50, p     

Subpontic osseous hyperplasia: a five-patient report

As an alternative approach to individually-focused understanding of HIV risk behavior, this study explored the relationship between social network characteristics and HIV-risk injecting behaviors. Subjects were 499 inner-city injection drug users (IDUs) recruited from the streets of Baltimore, Maryland. Analysis of structural and functional network data indicates that a substantial proportion of drug sharing network members also provided social support, often because of family and sexual partner relationships. IDUs with larger drug networks which also provided social support were more likely to share needles, while IDUs with larger drug networks which did not provide social support were more likely to inject in commercial settings. The findings suggest that social support from drug network members has differential effects on injecting HIV-risk behaviors among IDUs. HIV prevention efforts should be expanded to reach drug-sharing networks and should take into account their social support relationships.     

Critical issues in longitudinal and observational studies: purpose, short versus long term, selection of study instruments, methods, outcomes, and biases

Longitudinal observational studies (LOS) provide key information about outcomes and treatment effectiveness that are not available from other types of investigations, including randomized controlled trials. Although LOS are easy to perform, they are difficult to perform correctly. Major problems include recruitment, retention, and relevance, but the central problems in LOS are bias, understanding the nature of the biases, and reporting the biases. To advance the quality and validity of LOS there must be a uniform requirement for reporting detailed data that includes details about the sampled population and the sampling methods, the rationale for the selection of control subjects, the probable biases, and estimates of the extent and consequences of the biases. Sufficient covariates should be collected so that where possible statistical adjustment for bias can be made.     

Temporal sampling requirements for the tracer kinetics modeling of breast disease

The physiological parameters measured in the tracer kinetics modeling of data from a dynamic contrast-enhanced magnetic resonance (MR) breast exam (blood flow-extraction fraction product [FE], volume of the extracellular extravascular space [Ve], and blood volume [Vb]) may enable non-invasive diagnosis of breast cancer. One of the factors that compromises the accuracy and precision of the parameter estimates, and therefore their diagnostic potential, is the temporal resolution of the MR scans used to measure contrast agent (gadolinium-diethylenetriamine pentaacetic acid [Gd-DTPA]) concentration in an artery (arterial input function [AIF]) and in the tissue (tissue residue function [TRF]). Using computer simulations, we have examined, for several AIF widths, the errors introduced into estimates of tracer kinetic parameters in breast tissue due to insufficient temporal sampling. Temporal sampling errors can be viewed as uncertainties and biases in the parameter estimates introduced by the uncertainty in the relative alignments of the AIF, TRF, and sampling grid. These effects arise from the model's inherent sensitivity to error in either the AIF or TRF, which is dependent on the values of the tracer kinetic parameters and increases with AIF width. Based on the results of the simulations, to ensure that the error in FE and Ve will be under 10% of their true values, we recommend a rapid bolus injection of contrast agent (approximately 10 s), that the AIF be sampled every second, and that the TRF be sampled every 16 s or less. An accurate measurement of Vb requires that the TRF be sampled at least every 4 s. The results of these investigations can be used to set minimum dynamic imaging rates for tracer kinetics modeling of the breast.     

A proposed classification of veterinary epidemiosurveillance networks

With the signing of the General Agreement on Tariffs and Trade and the establishment of the World Trade Organisation, the trading environment for animal products has changed. Disease control measures can no longer be applied as trade barriers unless supported by scientific epidemiological data. In this context, it has become necessary, if not obligatory, to gain accurate and up-to-date knowledge about the epidemiological status of important infectious animal diseases. The role of veterinary epidemiosurveillance networks is therefore gaining importance. Furthermore, epidemiosurveillance contributes to the protection of animal populations from exotic or emerging diseases, as well as to the development and evaluation of disease control programmes. Despite the large diversity of surveillance networks, the authors propose a method of network classification. The criteria for classification are as follows: the type of disease being monitored (i.e., surveillance of exotic versus endemic diseases). The number of diseases concerned (i.e., focused networks versus broad-based networks). The area being covered (i.e., local, national or international networks). The population being monitored (i.e., whether the network is targeted at suspect or susceptible animals). The sampling strategy of the network (i.e., sample-based networks versus exhaustive networks). The method of collecting data (i.e., passive data collection versus active collection). The type of network management (i.e., autonomous management versus that which is integrated with other programmes). This classification is discussed and illustrated by examples published in the literature. It may aid in the future development of a grid for the evaluation of veterinary epidemiosurveillance networks.     

Measures of concurrency in networks and the spread of infectious disease

An investigation is made into the impact of concurrent partnerships on epidemic spread. Starting from a definition of concurrency on the level of individuals, the authors define ways to quantify concurrency on the population level. An index of concurrency based on graph theoretical considerations is introduced, and the way in which it is related to the degree distribution of the contact graph is demonstrated. Then the spread of an infectious disease on a dynamic partnership network is investigated. The model is based on a stochastic process of pair formation and separation and a process of disease transmission within partnerships of susceptible and infected individuals. Using Monte Carlo simulation, the spread of the epidemic is compared for contact patterns ranging from serial monogamy to situations where individuals can have many partners simultaneously. It is found that for a fixed mean number of partners per individual the distribution of these partnerships over the population has a major influence on the speed of the epidemic in its initial phase and consequently in the number of individuals who are infected after a certain time period.     

Decision analysis for treatment of early stage prostate cancer

OBJECTIVE: The purpose of this study is to compare reports of alcohol use, drug use and sexual behavior from 30-day Summary measures with an expanded version of a Timeline Follow-back (Timeline) interview technique among gay/bisexual men entering outpatient substance abuse treatment at a gay-identified agency. METHOD: Respondents (N = 418) first completed self-administered questionnaires covering the 30-day period prior to their last use of alcohol or drugs. Summary measures included alcohol use, number of days of use for five categories of drugs and number of episodes of anal intercourse (with and without condoms) by partner type (primary or secondary). Participants then completed the Timeline interview procedure to recall their daily drinking, drug use and sexual behavior during the same 30-day period. RESULTS: The findings indicate that the Timeline method yielded significantly lower estimates of mean number of drinks consumed when heavier than usual drinking days is included in the Summary measure (124.0 vs 147.0 drinks), mean number of days drugs were used (9.3 vs 10.7) and mean number of episodes of anal intercourse with a primary partner (1.2 vs 2.2). Differences generally remained significant when assessed by length of time between the study interview and last use of alcohol or drugs, with the exception of number of anal sex episodes with primary partners. CONCLUSIONS: These findings indicate that Timeline estimates are lower than estimates using a more standard method (Summary measures). Discrepancies between these findings and those reported by other researchers indicate a need for further exploration of the effects of the mode of administration on various populations.     

Bias in meta-analytic estimates of the absolute efficacy of psychotherapy.

Meta-analytic estimates of the absolute efficacy of psychotherapy indicate an effect size of approximately 0.80. However, various biases in primary and meta-analytic studies may have influenced this estimate. This study examines 4 nonsystematic biases that increase error variance (i.e., nonrandomized designs, methodological deficiencies, failure to use the study as the unit of analysis, and violations of homogeneity), 4 underestimation biases that primarily concern psychometric issues (i.e., unreliability of outcome measures, failure to report nonsignificant effect sizes, nonoptimal composite outcome measures, and nonstandardized outcome measures), and 8 overestimation biases (i.e., excluding nonsignificant effects from calculations of effect size estimates, failure to adjust for small sample bias, failure to separate studies using single-group pre-post designs vs. control group designs, using unweighted average effect sizes, analyzing biased partial samples that reflect treatment dropout and research attrition, researcher allegiance bias, publication bias, and wait-list control group bias). Wherever possible, evidence regarding the magnitude of these biases is presented, and methods for addressing these biases separately and collectively are discussed. Implications of the meta-analytic evidence on psychotherapy for the effect sizes of other psychological interventions are also considered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A call for a social network-oriented approach to services for survivors of intimate partner violence.

Despite the many hard-won victories of the antidomestic violence movement, it has had less success in reaching one of its own primary goals: that of making intimate partner violence a problem of the community rather than a problem between two individuals. Most mainstream domestic violence service models have not prioritized ongoing engagement of survivors' informal social support networks as a core part of their work. Yet the perpetration of domestic violence occurs within a community context that contributes to the maintenance or alleviation of the problem. Given extensive research on the centrality of social networks to the fabric of survivors' daily lives, as well as their ongoing safety and emotional well-being, it is critical to consider how domestic violence services and systems can align with these social networks more effectively. Following a review of research on the role of informal social support in survivors' lives, this article calls for a shift in mainstream domestic violence services toward a more network-oriented approach, one that highlights potential partnerships between professionals and survivors' informal social support networks. Such a shift would require a reconceptualization of the role of the domestic violence practitioner and the scope and nature of services. It would also raise a series of emergent research questions about how informal network members can best support survivors, how domestic violence services can help survivors engage with existing and new supporters, and the extent to which specific types of network-oriented practices can indeed improve survivors' safety and well-being. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The dissolution of romantic relationships: Factors involved in relationship stability and emotional distress.

A large sample of individuals involved in ongoing dating relationships completed an extensive questionnaire survey that assessed 10 factors: satisfaction with the current partner, closeness of the relationship, duration of the relationship, sexual nature of the relationship, the quality of the best actual and imagined alternative dating partner(s), the ease with which a suitable alternative partner could be found, exclusivity of the relationship, self-monitoring propensity, and orientation to sexual relations. Approximately 3 months later, all individuals were recontacted to determine whether they were still dating the same partner and if not, how much emotional distress they experienced following relationship dissolution. Analyses revealed that at a univariate level, all 10 factors successfully forecasted relationship stability. Three of the 10 factors—closeness, duration, and ease of finding an alternative partner—reliably and independently predicted the intensity and duration of emotional distress. Specifically, individuals who were close to their former partner, who had dated the former partner for a long time, and who believed they could not easily acquire a desirable alternative tended to experience more pronounced distress following dissolution. These results are discussed in terms of the investment model and recent theorizing on emotion in relationships. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Impact of combination therapies on HIV risk perceptions and sexual risk among HIV-positive and HIV-negative gay and bisexual men.

The availability of improved HIV treatments may prompt reduced concern about HIV and sexual risk. Gay and bisexual men (N?=?554, 17% HIV-positive) completed measures of treatment attitudes, sexual risk, and assumptions regarding the infectiousness of sexual partners. A substantial minority reported reduced HIV concern related to treatment advances. Reduced HIV concern was an independent predictor of sexual risk, particularly among HIV-positive men. In response to hypothetical scenarios describing sex with an HIV-positive partner, participants rated the risk of unprotected sex to be lower if the partner was taking combination treatments and had an undetectable viral load, relative to scenarios with a seropositive partner not taking combination treatments. Prevention efforts must address attitudinal shifts prompted by recent treatment successes, stressing the continued importance of safer sex, and that an undetectable viral load does not eliminate infection risks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Talking about interpersonal violence: Cultural influences on Latinas' identification and disclosure of sexual assault and intimate partner violence.

Low rates of disclosure among Latina survivors of sexual assault and intimate partner violence may be related to cultural influences that stigmatize disclosure and make identifying instances of sexual assault and intimate partner violence difficult. In an effort to add to existing literature, the current study conducted a series of 10 focus groups with Spanish-speaking Latinas of varying educational, immigration, and generational statuses to identify the range of cultural influences that affect Latinas' ability to identify and disclose instances of sexual assault and intimate partner violence. Results suggested that gender role ideologies, traditional beliefs about marriage, familism, taboos against talking about sex, respect for authority, lack of community resources, and fear of violence operate in different ways to obscure and justify acts of sexual assault and intimate partner violence and to maintain silence when such acts do occur. Yet, most participants also felt that other people, particularly Latinos living abroad and the older generation of Latinas living in the United States, held far more conservative and traditional beliefs than the participants themselves did, suggesting that important differences exist in both the acceptance of cultural beliefs and the mechanisms through which these beliefs affect Latinas' ability to identify and disclose instances of sexual assault and intimate partner violence. Implications of these findings are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neural networks predict response biases of female túngara frogs

Artificial neural networks have become useful tools for probing the origins of perceptual biases in the absence of explicit information on underlying neuronal substrates. Preceding studies have shown that neural networks selected to recognize or discriminate simple patterns may possess emergent biases toward pattern size of symmetry--preferences often exhibited by real females--and have investigated how these biases shape signal evolution. We asked whether simple neural networks could evolve to respond to an actual mate recognition signal, the call of the túngara frog, Physalaemus pustulosus. We found that not only were networks capable of recognizing the call of the túngara frog, but that they made remarkably accurate quantitative predictions about how well females generalized to many novel calls, and that these predictions were stable over several architectures. The data suggest that the degree to which P. pustulosus females respond to a call may often be an incidental by-product of a sensory system selected simply for species recognition.     

Using derivative estimates to describe intraindividual variability at multiple time scales.

The study of intraindividual variability is central to the study of individuals in psychology. Previous research has related the variance observed in repeated measurements (time series) of individuals to traitlike measures that are logically related. Intraindividual measures, such as intraindividual standard deviation or the coefficient of variation, are likely to be incomplete representations of intraindividual variability. This article shows that the study of intraindividual variability can be made more productive by examining variability of interest at specific time scales, rather than considering the variability of entire time series. Furthermore, examination of variance in observed scores may not be sufficient, because these neglect the time scale dependent relationships between observations. The current article outlines a method of using estimated derivatives to examine intraindividual variability through estimates of the variance and other distributional properties at multiple time scales. In doing so, this article encourages more nuanced discussion about intraindividual variability and highlights that variability and variance are not equivalent. An example with simulated data and an example relating variability in daily measures of negative affect to neuroticism are provided. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Assessing the validity of the achievement motive in the presence of random measurement error.

The presence of random measurement error in indicators of theoretical constructs biases observed estimates of relations among those constructs. Correcting for this bias is particularly important when random measurement error is substantial or is substantially different for indicators of distinct constructs included in a theoretical model. Validity assessment in the case of thematic apperceptive measures of the achievement motive (TAT n Achievement) has been vulnerable to interpretive errors because these indicators of the achievement motive are typically much less reliable than indicators of other constructs to which the motive may be related, and no correction has been made for the bias introduced by such differential measurement error. A causal modeling approach to validity assessment for TAT n Achievement is presented that incorporates explicit true-score measurement models of theoretical constructs. Data from J. Veroff et al (1981) on 413 adult US males confirm the hypothesis that the achievement motive construct is positively related to work satisfaction. Evidence for the discriminant validity of story content as opposed to story length, an issue raised in the literature on the TAT, is also presented in this nomological network. (56 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Investigating the numerical effects of ascertainment bias in linkage analysis: development of methods and preliminary results

It is general practice to have nonsingle ascertainment of pedigrees for linkage studies, along with intrafamilial sampling that is dependent on who among the related individuals was initially ascertained (Proband dependent or PD sampling). Vieland and Hodge [1995; 1996] have shown that under these conditions, the likelihood used in calculating the lod score is not strictly correct and can produce asymptotically biased estimates of the recombination fraction, theta. However they speculated that this bias would be small in most applications. This paper presents preliminary work aimed at quantifying the numerical magnitude of the bias introduced by PD sampling and nonsingle ascertainment in linkage analysis. We considered five generating models where we varied the ascertainment procedure, intrafamilial sampling scheme, and the sample size for each model. In this limited initial set of simulations, asymptotic bias in theta appears to be trivial, while PD sampling procedures can increase the efficiency of theta. These preliminary results support the view that the advantages of unsystematic ascertainment may offset any small estimation bias that may arise.     

Social networks and partner stress as predictors of adherence to medication, rehabilitation attendance, and quality of life following acute coronary syndrome.

Objective: This study examined whether social network size and partner stress predicted medication adherence, cardiac rehabilitation attendance, and quality of life 12 months following hospitalization for an acute coronary syndrome (ACS). Design: ACS patients (N = 193, M age = 60.6 years, SD = 11.4 years, 23% female) were recruited shortly following admission to 4 local hospitals. A prospective design was employed with follow-up data collected 12 months following hospital admission. Main Outcome Measures: Data were gathered on social network size and partner stress. The main outcomes assessed at 12 months were medication adherence, cardiac rehabilitation attendance, and quality of life (Short Form 36). Results: Partner stress predicted medication nonadherence, odds ratio: 2.89, (95% CI = 1.21, 6.95). ACS patients with large social networks were more likely to attend rehabilitation, odds ratio: 3.42, (95% CI = 1.42, 8.25). Analyses were adjusted for age, gender, clinical risk scores, readmission/recurrence, and negative affectivity. Both partner stress and smaller social network size were associated with poorer quality of life. Conclusion: Social network size and partner stress may partly exert their influence on coronary heart disease morbidity and mortality through recovery behaviors and maintenance of quality of life. (PsycINFO Database Record (c) 2010 APA, all rights reserved)