Brood size, sibling competition, and the cost of begging in great tits (Parus major)

Evolutionary theory of parent-offspring conflict explains begging displays of nestling birds as selfish attempts to influence parental food allocation. Models predict that this conflict may be resolved by honest signaling of offspring need to parents, or by competition among nestmates, leading to escalated begging scrambles. Although the former type of models has been qualitatively supported by experimental studies, the potential for a begging component driven by scramble competition cannot be excluded by the evidence. In a brood-size manipulation experiment with great tits, Parus major, we explored the scramble component in the begging activity of great tit nestlings by investigating the mechanisms of sibling competition in relation to brood size. While under full parental compensation, the feeding rate per nestling will remain constant over all brood sizes for both types of models; the scramble begging models alone predict an increase in begging intensity with brood size, if begging costs do not arise exclusively through predation. Great tit parents adjusted feeding rates to brood size and fed nestlings at similar rates and with similar prey sizes in all three brood-size categories. Despite full parental compensation, the begging and food solicitation activities increased with experimental brood size, whereas nestling body condition deteriorated. These findings support a scramble component in begging and suggest that the competition-induced costs of food solicitation behavior play an important role in the evolution of parent-offspring communicatio

Immunologic Response to Antiretroviral Therapy in Hepatitis C Virus-Coinfected Adults in a Population-Based HIV/AIDS Treatment Program

BackgroundWe sought to characterize the impact that hepatitis C virus (HCV) infection has on CD4 cells during the first 48 weeks of antiretroviral therapy (ART) in previously ART-naive human immunodeficiency virus (HIV)-infected patients MethodsThe HIV/AIDS Drug Treatment Programme at the British Columbia Centre for Excellence in HIV/AIDS distributes all ART in this Canadian province. Eligible individuals were those whose first-ever ART included 2 nucleoside reverse transcriptase inhibitors and either a protease inhibitor or a nonnucleoside reverse transcriptase inhibitor and who had a documented positive result for HCV antibody testing. Outcomes were binary events (time to an increase of ⩾75 CD4 cells/mm3 or an increase of ⩾10% in the percentage of CD4 cells in the total T cell population [CD4 cell fraction]) and continuous repeated measures. Statistical analyses used parametric and nonparametric methods, including multivariate mixed-effects linear regression analysis and Cox proportional hazards analysis ResultsOf 1186 eligible patients, 606 (51%) were positive and 580 (49%) were negative for HCV antibodies. HCV antibody-positive patients were slower to have an absolute (P<.001) and a fraction (P=.02) CD4 cell event. In adjusted Cox proportional hazards analysis (controlling for age, sex, baseline absolute CD4 cell count, baseline pVL, type of ART initiated, AIDS diagnosis at baseline, adherence to ART regimen, and number of CD4 cell measurements), HCV antibody-positive patients were less likely to have an absolute CD4 cell event (adjusted hazard ratio [AHR], 0.84 [95% confidence interval {CI}, 0.72-0.98]) and somewhat less likely to have a CD4 cell fraction event (AHR, 0.89 [95% CI, 0.70-1.14]) than HCV antibody-negative patients. In multivariate mixed-effects linear regression analysis, HCV antibody-negative patients had increases of an average of 75 cells in the absolute CD4 cell count and 4.4% in the CD4 cell fraction, compared with 20 cells and 1.1% in HCV antibody-positive patients, during the first 48 weeks of ART, after adjustment for time-updated pVL, number of CD4 cell measurements, and other factors ConclusionHCV antibody-positive HIV-infected patients may have an altered immunologic response to AR

Early mortality and loss to follow-up in HIV-infected children starting antiretroviral therapy in Southern Africa.

BACKGROUND: Many HIV-infected children in Southern Africa have been started on antiretroviral therapy (ART), but loss to follow up (LTFU) can be substantial. We analyzed mortality in children retained in care and in all children starting ART, taking LTFU into account. PATIENTS AND METHODS: Children who started ART before the age of 16 years in 10 ART programs in South Africa, Malawi, Mozambique, and Zimbabwe were included. Risk factors for death in the first year of ART were identified in Weibull models. A meta-analytic approach was used to estimate cumulative mortality at 1 year. RESULTS: Eight thousand two hundred twenty-five children (median age 49 months, median CD4 cell percent 11.6%) were included; 391 (4.8%) died and 523 (7.0%) were LTFU in the first year. Mortality at 1 year was 4.5% [95% confidence interval (CI): 2.8% to 7.4%] in children remaining in care, but 8.7% (5.4% to 12.1%) at the program level, after taking mortality in children and LTFU into account. Factors associated with mortality in children remaining in care included age [adjusted hazard ratio (HR) 0.37; 95% CI: 0.25 to 0.54 comparing > or =120 months with <18 months], CD4 cell percent (HR: 0.56; 95% CI: 0.39 to 0.78 comparing > or =20% with <10%), and clinical stage (HR: 0.12; 95% CI: 0.03 to 0.45 comparing World Health Organization stage I with III/IV). CONCLUSIONS: In children starting ART and remaining in care in Southern Africa mortality at 1 year is <5% but almost twice as high at the program level, when taking LTFU into account. Age, CD4 percentage, and clinical stage are important predictors of mortality at the individual level

Perceived impact of environmental barriers on participation among people living with spinal cord injury in Switzerland

Objective: To describe the impact of environmental barriers perceived by people living with spinal cord injury in the Swiss community and to compare this across subpopulations. Design: Cross-sectional study. Subjects: A total of 1,549 participants in the community survey of the Swiss spinal cord injury Cohort study. Methods: The perceived impact of environmental barriers on participation was measured with the Nottwil Environmental Factors Inventory Short Form (NEFI-SF). Physical independence was measured with the Spinal Cord Independence Measure Self Report (SCIM-SR). Perceived barriers were compared across people with different demographic and lesion characteristics. Multivariable regression modelling applying fractional polynomials was used to evaluate the overall perceived impact of barriers in relation to demographics, spinal cord injury characteristics, and physical independence. Results: Most perceived barriers were climatic conditions and inaccessibility of public and private infrastructure. Older participants, those with longer time since injury and participants with complete lesions indicated more problems with access. Females reported more attitudinal barriers. Approximately one-third of participants with complete tetraplegia reported obstacles related to assistance with personal care. A higher level of physical independence was associated with fewer perceived barriers. Conclusion: Despite living in a rich country with a well-developed social security system, many people with spinal cord injury in Switzerland experience participation restrictions due to environmental barriers; in particular women, people with non-traumatic spinal cord injury and limited physical independence

Detecting subgroups in social participation among individuals living with spinal cord injury:a longitudinal analysis of community survey data

STUDY DESIGN: Longitudinal community survey. OBJECTIVES: To determine subgroups in social participation of individuals living with spinal cord injury (SCI). SETTING: Community. METHODS: Data were collected in 2012 and 2017 as part of the community survey of the Swiss Spinal Cord Injury cohort. Participation was assessed using the 33-item Utrecht Scale of Evaluation of Rehabilitation-Participation evaluating frequency of, restrictions in and satisfaction with productive, leisure, and social activities. Linear mixed-effects model trees were used to distinguish subgroups in participation associated with sociodemographic and lesion characteristics. RESULTS: In all, 3079 observations were used for the analysis, of which 1549 originated from Survey 2012, 1530 from Survey 2017, and 761 from both surveys. Participants were mostly male (2012: 71.5%; 2017: 71.2%), aged on average 50 years (2012: 52.3; 2017: 56.5), with an incomplete paraplegia (2012: 37.5%; 2017: 41.8%) of traumatic origin (2012: 84.7%; 2017: 79.3%). There was limited within-person variation in participation over the 5-year period. Participation varied with age, SCI severity, education, financial strain, number of self-reported health conditions (SHCs), and disability pension level. Among modifiable parameters, the number of SHCs and disability pension level emerged as the most frequent partitioning variables, while education was most informative for participation in productive, leisure, and social activities. CONCLUSIONS: Long-term rehabilitation management and clinical practice should target people most prone to decreased participation in major life domains. Our study indicates that the alleviation of SHCs, engagement in further education, or adjusting disability pension level are promising areas to improve participation of persons living with SCI

Swiss national community survey on functioning after spinal cord injury:Protocol, characteristics of participants and determinants of non-response

Objective: To detail the protocol, recruitment, study population, response, and data quality of the first population-based community survey of the Swiss Spinal Cord Injury (SwiSCI) Cohort Study. Design: The survey consisted of 3 successive modules administered between September 2011 and March 2013. The first two modules queried demographics, lesion characteristics and key domains of functioning. The third module collected information on psychological personal factors and health behaviour; work integration; or health services and aging. Participants: Community-dwelling persons with chronic spinal cord injury in Switzerland. Methods: Descriptive analyses of the recruitment process, participant characteristics, and correspondence between self-reported and clinical data. Determinants for participation and the impact of non-response on survey results were assessed. Results: Out of 3,144 eligible persons 1,549 participated in the first two modules (cumulative response rate 49.3%). Approximately three-quarters of participants were male, with a median age of 53 years, and 78% had traumatic spinal cord injury. Record-linkage with medical records demonstrated substantial agreement with self-reported demographic and lesion characteristics. A minimal non-response bias was found. Conclusions: The community survey was effective in recruiting an unbiased sample, thus providing valuable information to study functioning, health maintenance, and quality of life in the Swiss SCI community

Metric properties of the Utrecht Scale for Evaluation of Rehabilitation -:Participation (USER-Participation) in persons with spinal cord injury living in Switzerland

Objective: To examine the metric properties of the Utrecht Scale for Evaluation of Rehabilitation-Participation (USER-Participation) in persons with spinal cord injury in Switzerland from a classical and item response theory perspective. Design: Cross-sectional survey. Subjects: Persons with spinal cord injury living in the Swiss community (n = 1,549). Methods: Score distributions and internal consistency were evaluated using Classical Test Theory. The Restrictions and Satisfaction scales were subjected to Rasch analysis. Anchored analyses were performed to account appropriately for items with structural missing. Results: Internal consistency was good for the Restrictions (alpha = 0.90) and Satisfaction scales (alpha = 0.90), but not for the Frequency scale (alpha = 0.65). Rasch analyses showed acceptable model fit for the Restrictions and Satisfaction scales after collapsing response categories of some items and merging some items into testlets. Differential item functioning was small. Anchoring allowed inclusion of the item work/education in the Restrictions scale and work/education and/or partner relationship in the Satisfaction scale. Conclusion: The Restrictions and Satisfaction scales of the USER-Participation showed satisfactory metric properties. The Frequency scale showed fewer optimal properties, but nonetheless provides important additional information regarding participation. Conversion tables were performed to transform USER-Participation raw scores into a 0-100 interval scale using Rasch-based ability estimates for use in epidemiological studies