The retail market for fresh and dry beans in Uganda: an investigation of cultivars in prices and implications for breeders

Twelve consumer retail markets in Uganda were studied 1998 in March and June of 1990 to determine the fresh and dry bean cultivars offered and to determine factors that explain variation in market prices. A total of 33 cultivars were offered in March and 30 in June in both the fresh and dry form. Kanyabwa and Nambale were the most frequently occurring cultivars. The revenue advantage of fresh over dry beans ranged from 30 to 279 percent across the cultivars sold. Farmers thus have a revenue incentive to supply fresh beans. Markets external to Kampala had significantly lower fresh, but not dry bean prices than Kampala markets. The bean grain characteristics size and color were not significant in explaining price variability. The implication for bean breeders in Uganda is that size should not be an important criterion for in a selection program and color should only be used when in conjunction with geographical area. The overall results suggest that preferences for beans, as reflected by consumer-prices paid, are a function of taste and grain size and color were not strong indicators or proxies of tast

O excesso de confiança dos produtores de milho no Brasil e o uso de contratos futuros

O objetivo deste artigo foi identificar sinais de excesso de confiança nos preços entre produtores de milho do Sul e do Centro-Oeste do Brasil. Entre outubro e novembro de 2008, 90 produtores foram selecionados para responderem questões relacionadas a seus conhecimentos do mercado futuro e a suas expectativas de preços. Uma grande parte dos entrevistados respondeu que não negociava contratos futuros por não possuir informação suficiente para isso. Os resultados revelaram que os produtores foram descalibrados quando estimaram os preços esperados na forma direta e indireta. Além disso, para a maior parte dos respondentes, a variância subjetiva obtida por meio dos questionários foi estatisticamente inferior à variância do mercado. Isto mostra que os produtores possuem uma percepção de risco inferior ao risco de mercado. Por fim, o artigo conclui que o efeito de excesso de confiança pode, parcialmente, explicar o baixo uso do mercado futuro de milho por parte dos produtores brasileiros, para garantir a proteção de preço do produto.<br>This paper aimed to identify signs of overconfidence among corn producers in the Southern and Central-Western regions in Brazil. Between October and November 2008, 90 farmers were chosen to answer questions regarding their knowledge of futures markets and price expectations. Most part of agents surveyed answered that they do not trade futures contracts because they do not have enough information. Results showed that respondents were miscalibrated when estimating directly-stated and the indirectly-stated expected prices. In addition, for most respondents, subjective variance for corn proves to be significantly less than the market variance, implying that producers perceive a risk that is lower than that of the market. Finally, the paper concludes that the overconfidence effect can partially explain the low use of futures markets by Brazilian corn producers to hedge their production

Positive and negative parenting in conduct disorder with high versus low levels of callous-unemotional traits

Less is known about the relationship between conduct disorder (CD), callous-unemotional (CU) traits, and positive and negative parenting in youth compared to early childhood. We combined traditional univariate analyses with a novel machine learning classifier (Angle-based Generalized Matrix Learning Vector Quantization) to classify youth (N = 756; 9-18 years) into typically developing (TD) or CD groups with or without elevated CU traits (CD/HCU, CD/LCU, respectively) using youth- and parent-reports of parenting behavior. At the group level, both CD/HCU and CD/LCU were associated with high negative and low positive parenting relative to TD. However, only positive parenting differed between the CD/HCU and CD/LCU groups. In classification analyses, performance was best when distinguishing CD/HCU from TD groups and poorest when distinguishing CD/HCU from CD/LCU groups. Positive and negative parenting were both relevant when distinguishing CD/HCU from TD, negative parenting was most relevant when distinguishing between CD/LCU and TD, and positive parenting was most relevant when distinguishing CD/HCU from CD/LCU groups. These findings suggest that while positive parenting distinguishes between CD/HCU and CD/LCU, negative parenting is associated with both CD subtypes. These results highlight the importance of considering multiple parenting behaviors in CD with varying levels of CU traits in late childhood/adolescence. Copyright © Cambridge University Press 2020

Community violence exposure and conduct problems in children and adolescents with conduct disorder and healthy controls

Exposure to community violence through witnessing or being directly victimized has been associated with conduct problems in a range of studies. However, the relationship between community violence exposure (CVE) and conduct problems has never been studied separately in healthy individuals and individuals with conduct disorder (CD). Therefore, it is not clear whether the association between CVE and conduct problems is due to confounding factors, because those with high conduct problems also tend to live in more violent neighborhoods, i.e., an ecological fallacy. Hence, the aim of the present study was: (1) to investigate whether the association between recent CVE and current conduct problems holds true for healthy controls as well as adolescents with a diagnosis of CD; (2) to examine whether the association is stable in both groups when including effects of aggression subtypes (proactive/reactive aggression), age, gender, site and socioeconomic status (SES); and (3) to test whether proactive or reactive aggression mediate the link between CVE and conduct problems. Data from 1178 children and adolescents (62% female; 44% CD) aged between 9 years and 18 years from seven European countries were analyzed. Conduct problems were assessed using the Kiddie-Schedule of Affective Disorders and Schizophrenia diagnostic interview. Information about CVE and aggression subtypes was obtained using self-report questionnaires (Social and Health Assessment and Reactive-Proactive aggression Questionnaire (RPQ), respectively). The association between witnessing community violence and conduct problems was significant in both groups (adolescents with CD and healthy controls). The association was also stable after examining the mediating effects of aggression subtypes while including moderating effects of age, gender and SES and controlling for effects of site in both groups. There were no clear differences between the groups in the strength of the association between witnessing violence and conduct problems. However, we found evidence for a ceiling effect, i.e., individuals with very high levels of conduct problems could not show a further increase if exposed to CVE and vice versa. Results indicate that there was no evidence for an ecological fallacy being the primary cause of the association, i.e., CVE must be considered a valid risk factor in the etiology of CD. © 2017, Frontiers Media S.A. All rights reserved