a systematic review on sampling methods

PMCID: 4627393 PMID: 26518345BACKGROUND: In public health, hard-to-reach populations are often recruited by non-probabilistic sampling methods that produce biased results. In order to overcome this, several sampling methods have been improved and developed in the last years. The aim of this systematic review was to identify all current methods used to survey most-at-risk populations of men who have sex with men and sex workers. The review also aimed to assess if there were any relations between the study populations and the sampling methods used to recruit them. Lastly, we wanted to assess if the number of publications originated in middle and low human development (MLHD) countries had been increasing in the last years. METHODS: A systematic review was conducted using electronic databases and a total of 268 published studies were included in the analysis. RESULTS: In this review, 11 recruitment methods were identified. Semi-probabilistic methods were used most commonly to survey men who have sex with men, and the use of the Internet was the method that gathered more respondents. We found that female sex workers were more frequently recruited through non-probabilistic methods than men who have sex with men (odds = 2.2; p < 0.05; confidence interval (CI) [1.1-4.2]). In the last 6 years, the number of studies based in middle and low human development countries increased more than the number of studies based in very high and high human development countries (odds = 2.5; p < 0.05; CI [1.3-4.9]). CONCLUSIONS: This systematic literature review identified 11 methods used to sample men who have sex with men and female sex workers. There is an association between the type of sampling method and the population being studied. The number of studies based in middle and low human development countries has increased in the last 6 years of this study.publishersversionpublishe

Physical exercise and functional fitness of older adults in day care center

Poster presented at the 2nd International Congress of CiiEM - Translational Research and Innovation in Human and Health Science. 11-13 June, 2017, Campus Egas Moniz, Monte de Caparica, Portugal.N/

Phenolic extracts of Fragaria vesca L. roots with anti-Candida potential: chemical characterization and in vitro antifungal capacity

Candida species, considered a commensal microorganism of the human flora, have caused a profound impact at public health level. Furthermore, there are alarming numbers of microorganisms with acquired drug resistance, contributing to the inefficacy of antifungal agents [1]. Thus, efficient alteratives to the current antifungal agents and without side effects need to be discovered. Plants comprise numerous bioactive compounds responsible for a wide variety of bioactive properties. Fragaria vesca L. (wild strawberry), belongs to the Rosaceae family and its fruits are commonly used for culinary purposes. Only its leaves are used for medicinal purposes, due to the astringent (hemostatic and antidiarrheal), diuretic, depurative and tonic effects [2]. A few studies have been carried out in order to evaluate the bioactive potential of its roots [3], but to the authors knowledge, no reports are available regarding its antifungal potential against Candida species. Thus, the aim of the present study was to evaluate the antifungal potential of the hydromethanolic extract obtained from F. vesca roots, against nineteen Candida strains, belonging to C. albicans, C. glabrata, C. parapsilosis and C. tropicalis species. At the tested concentration (50 mg/mL), a most pronounced inhibitory effect was observed against C. tropicalis and C. parapsilosis (inhibitory zones varying between 9-10 and 10 mm, respectively). The obtained results remained similar after 24h, 48h and even 72h. Considering the evidenced antifungal potential, and taking into account its chemical composition, the observed effects could be attributed to the presence of phenolic compounds, such as flavan-3- ols, being (epi)catechin derivatives (mainly procyanidins) the main compounds found, as also elagic acid derivatives. Further studies should be conducted in order to identify the active principle(s) responsible for the observed effects and the corresponding mechanism of action

Depressive symptoms and its associated factors in 13-year-old urban adolescents.

The available estimates reveal that 20-50% of adolescents report depressive symptoms, being one of the most prevalent health problems in adolescence. The aim of this study was to assess the prevalence of depressive symptoms in a community sample of 13-year-old adolescents and identify associated features. Thirteen year-old adolescents attending private and public schools in Porto (n = 1,988, 52.2% females) were evaluated from October 2003 to June 2004 and completed a questionnaire including health behaviors and the Beck Depression Inventory II. A questionnaire on parents' socio-demographics and clinical characteristics was sent home. Data were analyzed separately by sex. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression. The prevalence of depressive symptoms was 18.8% in girls and 7.6% in boys (p < 0.001). Boys with a family history of depression and girls with smoking habits had a significantly increased risk of depressive symptoms (OR = 2.18, 95%CI 1.00-4.71; OR = 2.34, 95%CI 1.46-3.76). Menarche at an early age significantly increased the risk of depressive symptoms. The characteristics most strongly associated with depressive symptoms were family history of depression among boys, tobacco consumption and an early age at menarche among girls. The high prevalence of depressive symptoms early in adolescence calls for the awareness of public health professionals.publishersversionpublishe

um estudo de caso em Belo Horizonte, Minas Gerais

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Uncovering the Use of Fucoxanthin and Phycobiliproteins into Solid Matrices to Increase Their Emission Quantum Yield and Photostability

In the search for a better and brighter future, the use of natural luminescent renewable materials as substitutes for synthetic ones in the energy field is of prime importance. The incorporation of natural pigments (e.g., xanthophylls and phycobiliproteins) is a fundamental step in a broad spectrum of applications that are presently marred by their limited stability. The incorporation of bio-based luminescent molecules into solid matrices allows the fabrication of thin films, which may dramatically increase the range of applications, including sustainable photovoltaic systems, such as luminescent solar concentrators or downshifting layers. In this work, we incorporated R-phycoerythrin (R-PE), C-phycocyanin (C-PC), and fucoxanthin (FX) into poly(vinyl alcohol) (PVA) and studied their optical properties. It was found that the emission and excitation spectra of the phycobiliproteins and FX were not modified by incorporation into the PVA matrix. Moreover, in the case of FX, the emission quantum yield (η) values also remained unaltered after incorporation, showing the suitability of the PVA as a host matrix. A preliminary photostability study was performed by exposing the solid samples to continuous AM1.5G solar radiation, which evidenced the potential of these materials for future photovoltaics.publishe

Physical distancing and mental well-being in youth population of Portugal and Brazil during the COVID-19 pandemic

Funding Information: This paper was made possible with the scholarship from FCT and to the Unidade de I&D CHRC – Comprehensive Health Research Centre (UI/BD/150908/2021). Also to CAPES (Code 001) and CNPQ (Research Productivity Scholarship Process 304483/2018-4). The databases are anonymous, guaranteeing data confidentiality. Funding Information: Fundação para a ciência e tecnologia (FCT) and the Unidade de I&D CHRC – Comprehensive Health Research Centre (UI/BD/150908/2021). Also to CAPES (Code 001) and CNPQ (Research Productivity Scholarship Process 304483/2018-4) Publisher Copyright: © 2022Background: The COVID-19 pandemic may affect youth's physical and mental well-being, partially because of the countries' rules to contain the virus from spreading. However, there is still uncertainty about the impact of physical distancing on youth's mental health. We aimed to estimate the prevalence of feeling agitated, anxious, down, sad, or low mood (FNF) due to physical distance measures and verify which factors are associated with young Portuguese and Brazilian people. Methods: We used cross-sectional data from the instrument "COVID-19 Barometer: Social Opinion"in Portugal (March 2020 and September 2021) and from "COVID-19 Social Thermometer"in Brazil (August 2020 to April 2021); these surveys included data regarding the health and socioeconomic impact on the population. The health and sociodemographic variables of the two countries were summarized as absolute and relative frequencies. A multivariable logistic regression model was fit by country to estimate the relation between FNF and selected variables of interest. Results: Approximately 36% of the sample studied reported anxiety, agitation, sadness, or low mood almost every day in Portugal and 52% in Brazil due to physical distancing. In Portugal, having more than two comorbidities represented a greater chance of experiencing FNF every day or almost every day (odds ratio [OR] = 1.51 [CI: 1.22-1.87]) than those without comorbidities. In contrast, having a university education level represented a protector factor (OR = 0.76 [CI: 0.67-0.88]). In Brazil, being unemployed increased the chance of FNF compared to students (OR = 11.2). Conclusions: Physical distancing measures have impacted the mental well-being of the young population in Portugal and Brazil. The countries must make a quick effort to attend to and protect young people's well-being and mental health in the changing context of the current pandemic.publishersversioninpres

Reduced hedonic valuation of rewards and unaffected cognitive regulation in chronic stress

Cognition can influence choices by modulation of decision-making processes. This cognitive regulation is defined as processing information, applying knowledge, and changing preferences to consciously modulate decisions. While cognitive regulation of emotions has been extensively studied in psychiatry, few works have detailed cognitive regulation of decision-making. Stress may influence emotional behavior, cognition, and decision-making. In addition, the brain regions responsible for decision-making are sensitive to stress-induced changes. Thus, we hypothesize that chronic stress may disrupt the ability to regulate choices. Herein, we used a functional magnetic resonance imaging task where fourteen control and fifteen chronically stressed students had to cognitively upregulate or downregulate their craving before placing a bid to obtain food. We found that stressed participants placed lower bids to get the reward and chose less frequently higher bid values for food. Nevertheless, we did not find neural and behavioral differences during cognitive regulation of craving. Our outcomes revealed that chronic stress impacts decision-making after cognitive regulation of craving by reducing the valuation of food rewards but not cognitive modulation itself. Importantly, our results need further validation with larger sample sizes.MyHealth project (DoIT – Desenvolvimento e Operacionalização da Investigação de Translação, Contract DoIT-13853) and the BIAL Foundation, Porto, Portugal (Grant No. PT/FB/BL-2016-206). This work was also funded by the FEDER funds, through the Competitiveness Factors Operational Programme (COMPETE), and by national funds, through the Foundation for Science and Technology (FCT), under the scope of the project POCI-01-0145-FEDER-007038. This manuscript has been developed under the scope of the project NORTE-01-0145-FEDER-000013, supported by the Northern Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (FEDER). PaM was supported by a fellowship of the project “SwitchBox” (Contract HEALTH-F2-2010-259772). SF was supported by a combined Ph.D. scholarship from the FCT and the company iCognitus4ALL – IT Solutions, Lda (PD/BDE/127839/2016). RM was supported by the combined FCT and Enlightenment, Lda fellowship (PDE/BDE/113604/2015) from the PhDiHES progra