Atraso dos reforços, taxa de respostas e resistência à mudança

Dissertação (mestrado)—Universidade de Brasília, Instituto de Psicologia, Departamento de Processos Psicológicos Básicos, Programa de Pós-Graduação em Ciências do Comportamento, 2019.Os efeitos do atraso dos reforços sobre a resistência à mudança foram avaliados em dois experimentos com ratos. No Experimento 1, na Linha de Base (LB), ratos foram expostos a um esquema múltiplo com dois componentes. No componente imediato, um esquema tandem intervalo variável (VI) reforçamento diferencial de baixas taxas (DRL) estava em vigor; no componente com atraso (não-resetável), um esquema tandem VI tempo fixo (FT) 3 s, 8 s ou 12 s estava em vigor. Na LB, as taxas de reforço foram semelhantes entre os componentes; em quatro condições, as taxas de resposta foram semelhantes entre os componentes e, em nove condições, as taxas de resposta foram maiores no componente imediato do que no componente com atraso. Em cada condição, extinção esteve em vigor em cada componente durante o Teste. No Experimento 2, na LB, ratos foram expostos a um esquema múltiplo com três componentes. No componente imediato, estava em vigor um esquema tandem VI DRL; no componente com atraso menor (resetável), estava em vigor um esquema tandem VI reforçamento diferencial de outros comportamentos (DRO) 8 s, 3 s ou 3 s; no componente com atraso maior (resetável), estava em vigor um tandem VI DRO 12 s, 12 s ou 6 s. Na LB, as taxas de reforço foram semelhantes entre os componentes e as taxas de resposta foram maiores no componente imediato do que nos componentes com atraso. Em cada condição, foram conduzidos Testes de extinção e saciação. No Experimento 1, nas condições com taxas de respostas iguais entre componentes na LB, a resistência à extinção não foi sistematicamente diferente entre componentes do esquema múltiplo. No entanto, nas condições em que as taxas de resposta foram diferentes entre os componentes do esquema múltiplo na LB, a resistência foi, em geral, maior no componente com atraso do que no componente imediato. No Experimento 2, esses resultados foram replicados: em ambos os testes, a resistência à mudança foi maior nos componentes com atraso do que no componente imediato, embora a diferença na resistência entre componentes tenha sido maior nos testes de extinção que nos testes de saciação. Além disso, os resultados de ambos os experimentos indicam que os efeitos do atraso dos reforços sobre a resistência são modulados pela diferença na taxa de respostas entre os componentes na LB. Exceto pelos testes de saciação (Experimento 2), observou-se uma relação direta entre a resistência à mudança diferencial e a diferença na taxa de respostas entre os componentes do múltiplo na LB. Os resultados do presente estudo não replicam aqueles de estudos anteriores com pombos e humanos, em que foi observada maior resistência à mudança no componente imediato do que no componente com atraso.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq).The effects of reinforcement delay on resistance to change were investigated in two experiments with rats. In Experiment 1, in Baseline (BL), rats were exposed to a two-component multiple schedule. In the immediate component, a tandem variable interval (VI) differential reinforcement of low rates (DRL) schedule was in effect; in the delay component (nonresetting), a tandem VI fixed-time (FT) 3 s, 8 s or 12 s schedule was in effect. In BL, reinforcement rates were similar between components; in four conditions, response rates were similar between components and, in nine conditions, response rates were higher in the immediate than in the delay component. In each condition, extinction was in effect in each component during the Test. In Experiment 2, in BL, rats were exposed to a three-component multiple schedule. In the immediate component, a tandem VI DRL schedule was in effect; in the shorter delay (resetting) component, a tandem VI differential reinforcement of other behaviors (DRO) 8 s, 3 s or 3 s schedule was in effect; in the longer delay (resetting) component a tandem VI DRO 12 s, 12 s or 6 s schedule also was in effect. In BL, reinforcement rates were similar between components and response rates were higher in the immediate than in the delay components. In each condition, extinction and satiation tests were conducted. In Experiment 1, in conditions with equal response rates between components in BL, resistance to extinction was not systematically different between components of the multiple schedule. However, in conditions in which response rates were different between components of the multiple schedule in BL, resistance to extinction was, in general, greater in the delay than in the immediate component. These results were replicated in Experiment 2: in both tests, resistance was greater in the delay components than in the immediate component, although the difference in resistance between components was greater in the extinction than in satiation tests. Additionally, the results of both experiments suggest that the effects of delay of reinforcement on resistance to change are modulated by the difference in response rates between components in BL. Except for the satiation tests (Experiment 2), a direct relation between differential resistance to change and the difference in response rates between components in BL was observed. The results of the present study do not replicate those of previous studies with pigeons and humans, in which greater resistance to change in the immediate than in the delay component was observed

Prevalência e determinantes precoces dos transtornos mentais comuns na coorte de nascimentos de 1982, Pelotas, RS Prevalencia y determinantes precoces de los trastornos mentales comunes en la cohorte de nacimientos de 1982, Pelotas, Sur de Brasil Prevalence and early determinants of common mental disorders in the 1982 birth cohort, Pelotas, Southern Brazil

OBJETIVO: Estimar a prevalência de transtornos mentais comuns e sua associação com fatores de risco numa coorte de adultos jovens. MÉTODOS: Estudo transversal aninhado à coorte de nascimentos de 1982 de Pelotas, RS. Em 2004-5, 4.297 indivíduos foram entrevistados em visita domiciliar. A probabilidade de transtornos mentais comuns foi estimada pelo Self-Report Questionnaire. Os fatores de risco incluíram variáveis socioeconômicas, demográficas, perinatais e ambientais. A análise foi estratificada por sexo e as razões de prevalência simples e ajustadas foram estimadas utilizando-se regressão de Poisson. RESULTADOS: A prevalência de transtornos mentais comuns na população geral foi 28,0%; 32,8% e 23,5%, respectivamente, entre mulheres e homens. Independentemente da pobreza em 1982, homens e mulheres pobres em 2004-5 apresentaram risco aproximado de 1,5 para esses transtornos (p<0,001), quando comparados aos que nunca foram pobres. Entre as mulheres, ter sido pobre na infância (p<0,001) e ter cor da pele preta ou parda (p=0,002) também aumentou o risco para transtornos mentais comuns. O baixo peso ao nascer e a duração da amamentação não estiveram associadas com o risco desses transtornos. CONCLUSÕES: A maior prevalência de transtornos mentais comuns nos indivíduos com baixa renda familiar e de minorias étnico-raciais mostra haver impacto das desigualdades sociais, presentes no nascimento, sobre esses transtornos.<br>OBJETIVO: Estimar la prevalencia de trastornos mentales comunes y su asociación con factores de riesgo en una cohorte de adultos jóvenes. MÉTODOS: Estudio transversal anidado a la cohorte de nacimientos de 1982 de Pelotas (Sur de Brasil). En 2004-5, 4.297 individuos fueron entrevistados en visita domiciliar. La probabilidad de trastornos mentales comunes fue estimada por el Self-Report Questionnaire. Los factores de riesgo incluyeron variables socioeconómicas, demográficas, perinatales y ambientales. El análisis fue estratificado por sexo y las razones de prevalencia simples y ajustadas fueron estimadas utilizándose regresión de Poisson. RESULTADOS: La prevalencia de trastornos mentales comunes en la población general fue de 28,0%; 32,8% y 23,5%, respectivamente, entre mujeres y hombres. Independientemente de la pobreza en 1982, hombres y mujeres pobres en 2004-5 presentaron riesgo aproximado de 1,5 para esos trastornos (p<0,001), cuando se compararon con los que nunca fueron pobres. Entre las mujeres, haber sido pobre en la infancia (p<0,001) y tener color de piel negra o parda (p=0,002) también aumentó el riesgo para trastornos mentales comunes. El bajo peso al nacer y la duración del amamantamiento no estuvieron asociados con el riesgo de esos trastornos. CONCLUSIONES: La mayor prevalencia de trastornos mentales comunes en los individuos con baja renta familiar y de minorías étnico-raciales muestra haber impacto de las desigualdades sociales, presentes en el nacimiento, sobre esos trastornos.<br>OBJECTIVE: To estimate the prevalence of common mental disorders and assess its association with risk factors in a cohort of young adults. METHODS: Cross-sectional study nested in a 1982 birth cohort study conducted in Pelotas, Southern Brazil. In 2004-5, 4,297 subjects were interviewed during home visits. Common mental disorders were assessed using the Self-Report Questionnaire. Risk factors included socioeconomic, demographic, perinatal, and environmental variables. The analysis was stratified by gender and crude and adjusted prevalence ratios were estimated by Poisson regression. RESULTS: The overall prevalence of common mental disorders was 28.0%; 32.8% and 23.5% in women and men, respectively. Men and women who were poor in 2004-5, regardless of their poor status in 1982, had nearly 1.5-fold increased risk for common mental disorders (p<0.001) when compared to those who have never been poor. Among women, being poor during childhood (p<0.001) and black/mixed skin color (p=0.002) increased the risk for mental disorders. Low birth weight and duration of breastfeeding were not associated to the risk of these disorders. CONCLUSIONS: Higher prevalence of common mental disorders among low-income groups and race-ethnic minorities suggests that social inequalities present at birth have a major impact on mental health, especially common mental disorders

Avaliação no Ensino Médico: o papel do portfólio nos currículos baseados em metodologias ativas

As atuais mudanças na educação médica - relacionadas às transformações em curso nas sociedades democráticas contemporâneas - têm colocado em questão, de modo cada vez mais incisivo, os aspectos relativos à avaliação dos processos de ensino-aprendizagem, cabendo a formulação de novos métodos/estratégias, capazes de ultrapassar a orientação somativa prevalecente na avaliação. Neste contexto, discutem-se, no presente artigo, elementos para a construção desta nova avaliação, destacando-se o uso do portfólio

Geoeconomic variations in epidemiology, ventilation management, and outcomes in invasively ventilated intensive care unit patients without acute respiratory distress syndrome: a pooled analysis of four observational studies

Background: Geoeconomic variations in epidemiology, the practice of ventilation, and outcome in invasively ventilated intensive care unit (ICU) patients without acute respiratory distress syndrome (ARDS) remain unexplored. In this analysis we aim to address these gaps using individual patient data of four large observational studies. Methods: In this pooled analysis we harmonised individual patient data from the ERICC, LUNG SAFE, PRoVENT, and PRoVENT-iMiC prospective observational studies, which were conducted from June, 2011, to December, 2018, in 534 ICUs in 54 countries. We used the 2016 World Bank classification to define two geoeconomic regions: middle-income countries (MICs) and high-income countries (HICs). ARDS was defined according to the Berlin criteria. Descriptive statistics were used to compare patients in MICs versus HICs. The primary outcome was the use of low tidal volume ventilation (LTVV) for the first 3 days of mechanical ventilation. Secondary outcomes were key ventilation parameters (tidal volume size, positive end-expiratory pressure, fraction of inspired oxygen, peak pressure, plateau pressure, driving pressure, and respiratory rate), patient characteristics, the risk for and actual development of acute respiratory distress syndrome after the first day of ventilation, duration of ventilation, ICU length of stay, and ICU mortality. Findings: Of the 7608 patients included in the original studies, this analysis included 3852 patients without ARDS, of whom 2345 were from MICs and 1507 were from HICs. Patients in MICs were younger, shorter and with a slightly lower body-mass index, more often had diabetes and active cancer, but less often chronic obstructive pulmonary disease and heart failure than patients from HICs. Sequential organ failure assessment scores were similar in MICs and HICs. Use of LTVV in MICs and HICs was comparable (42·4% vs 44·2%; absolute difference -1·69 [-9·58 to 6·11] p=0·67; data available in 3174 [82%] of 3852 patients). The median applied positive end expiratory pressure was lower in MICs than in HICs (5 [IQR 5-8] vs 6 [5-8] cm H2O; p=0·0011). ICU mortality was higher in MICs than in HICs (30·5% vs 19·9%; p=0·0004; adjusted effect 16·41% [95% CI 9·52-23·52]; p&lt;0·0001) and was inversely associated with gross domestic product (adjusted odds ratio for a US$10 000 increase per capita 0·80 [95% CI 0·75-0·86]; p&lt;0·0001). Interpretation: Despite similar disease severity and ventilation management, ICU mortality in patients without ARDS is higher in MICs than in HICs, with a strong association with country-level economic status

Health-status outcomes with invasive or conservative care in coronary disease

BACKGROUND In the ISCHEMIA trial, an invasive strategy with angiographic assessment and revascularization did not reduce clinical events among patients with stable ischemic heart disease and moderate or severe ischemia. A secondary objective of the trial was to assess angina-related health status among these patients. METHODS We assessed angina-related symptoms, function, and quality of life with the Seattle Angina Questionnaire (SAQ) at randomization, at months 1.5, 3, and 6, and every 6 months thereafter in participants who had been randomly assigned to an invasive treatment strategy (2295 participants) or a conservative strategy (2322). Mixed-effects cumulative probability models within a Bayesian framework were used to estimate differences between the treatment groups. The primary outcome of this health-status analysis was the SAQ summary score (scores range from 0 to 100, with higher scores indicating better health status). All analyses were performed in the overall population and according to baseline angina frequency. RESULTS At baseline, 35% of patients reported having no angina in the previous month. SAQ summary scores increased in both treatment groups, with increases at 3, 12, and 36 months that were 4.1 points (95% credible interval, 3.2 to 5.0), 4.2 points (95% credible interval, 3.3 to 5.1), and 2.9 points (95% credible interval, 2.2 to 3.7) higher with the invasive strategy than with the conservative strategy. Differences were larger among participants who had more frequent angina at baseline (8.5 vs. 0.1 points at 3 months and 5.3 vs. 1.2 points at 36 months among participants with daily or weekly angina as compared with no angina). CONCLUSIONS In the overall trial population with moderate or severe ischemia, which included 35% of participants without angina at baseline, patients randomly assigned to the invasive strategy had greater improvement in angina-related health status than those assigned to the conservative strategy. The modest mean differences favoring the invasive strategy in the overall group reflected minimal differences among asymptomatic patients and larger differences among patients who had had angina at baseline

Initial invasive or conservative strategy for stable coronary disease

BACKGROUND Among patients with stable coronary disease and moderate or severe ischemia, whether clinical outcomes are better in those who receive an invasive intervention plus medical therapy than in those who receive medical therapy alone is uncertain. METHODS We randomly assigned 5179 patients with moderate or severe ischemia to an initial invasive strategy (angiography and revascularization when feasible) and medical therapy or to an initial conservative strategy of medical therapy alone and angiography if medical therapy failed. The primary outcome was a composite of death from cardiovascular causes, myocardial infarction, or hospitalization for unstable angina, heart failure, or resuscitated cardiac arrest. A key secondary outcome was death from cardiovascular causes or myocardial infarction. RESULTS Over a median of 3.2 years, 318 primary outcome events occurred in the invasive-strategy group and 352 occurred in the conservative-strategy group. At 6 months, the cumulative event rate was 5.3% in the invasive-strategy group and 3.4% in the conservative-strategy group (difference, 1.9 percentage points; 95% confidence interval [CI], 0.8 to 3.0); at 5 years, the cumulative event rate was 16.4% and 18.2%, respectively (difference, 121.8 percentage points; 95% CI, 124.7 to 1.0). Results were similar with respect to the key secondary outcome. The incidence of the primary outcome was sensitive to the definition of myocardial infarction; a secondary analysis yielded more procedural myocardial infarctions of uncertain clinical importance. There were 145 deaths in the invasive-strategy group and 144 deaths in the conservative-strategy group (hazard ratio, 1.05; 95% CI, 0.83 to 1.32). CONCLUSIONS Among patients with stable coronary disease and moderate or severe ischemia, we did not find evidence that an initial invasive strategy, as compared with an initial conservative strategy, reduced the risk of ischemic cardiovascular events or death from any cause over a median of 3.2 years. The trial findings were sensitive to the definition of myocardial infarction that was used