Daily volume, intraday and overnight returns for volatility prediction: profitability or accuracy?

This article presents a comprehensive analysis of the relative ability of three information sets—daily trading volume, intraday returns and overnight returns—to predict equity volatility. We investigate the extent to which statistical accuracy of one-day-ahead forecasts translates into economic gains for technical traders. Various profitability criteria and utility-based switching fees indicate that the largest gains stem from combining historical daily returns with volume information. Using common statistical loss functions, the largest degree of predictive power is found instead in intraday returns. Our analysis thus reinforces the view that statistical significance does not have a direct mapping onto economic value. As a byproduct, we show that buying the stock when the forecasted volatility is extremely high appears largely profitable, suggesting a strong return-risk relationship in turbulent conditions

Molecular Identification of Listeria monocytogenes in Raw Hamburgers from Kerman, South-East of Iran

Background: Listeria monocytogenes is a Gram-positive and facultative anaerobic food-borne bacterium which is capable of intra and extra cellular growth. L. monocytogenes usually can exist on different surfaces and instruments at production and processing sites of food products with animal origin. In Iran, the consumption of burger has increased recently, but its safety is still of great concern. Despite few reports from some areas of Iran, there is limited information about burger contamination in Kerman province. Therefore, this research was set to molecular identification of L. monocytogenes in hamburgers distributed in Kerman, Iran. Methods: A total of 100 raw hamburgers were collected from 20 fast food/sandwich shops in Kerman city, Iran during summer 2014. The hamburgers stored in ice box and transported to the food hygiene laboratory. The samples were microbiologically analyzed for the presence of L. monocytogenes. The isolated bacteria were confirmed by molecular assay. Results: Three out of 100 (3%) hamburger samples were biochemically diagnosed as Listeria contamination; however molecular identification assay confirmed that two of them were L. monocytogenes. Conclusion: Although the prevalence rate of L. monocytogenes was not high in hamburger samples of Kerman, the risk of human listeriosis must not be ignored or underestimated. Further surveys are required in future for risk assessment of this pathogenic bacterium in other food products distributed in the country.&nbsp

Income Gradient in Children’s Physical Activity: Diminished Returns in Black Families

Background: While socioeconomic status (SES) indicators, such as family income, are among the primary drivers of individual health behaviors, the effects of these indicators on health behaviors may be weaker for racial/ethnic minorities, as described by the Marginalization related Diminished Returns (MDRs) phenomenon. Objectives: Built on the MDRs framework, this study used a national sample of 9 and 10 year old children with the following two aims: First, to test the association between household income and physical activity, and second, to test racial/ethnic variation in these associations. Methods: This cross-sectional study used the Adolescent Brain Cognitive Development (ABCD) baseline data. Participants included 9358 individuals who were either Black or White. Age, sex, racial/ethnicity, family structure (parental marital status), and frequency of physical activity were measured. Linear regression was used for data analysis. Results: Overall, high family income showed a positive association with physical activity in the overall population. We documented a statistically significant interaction between race/ethnicity and household income on frequency of physical activity, showing weaker effects of family income on children’s physical activity in Black than White families. Conclusion: We observed that household SES indicators, such as family income, have a larger effect on increasing children’s physical activity in White than Black families. Due to the existing MDRs, defined as weaker effects of family SES for racial/ethnic minority than White families, Black children from high SES families engage in less healthy behaviors than their White counterparts. MDRs sustain racial/ethnic disparities across class and SES lines.</jats:p

Unhealthy Diet of High Socioeconomic Children of Color: Marginalization-Related Diminished Returns

Background: While socioeconomic status (SES) indicators such as parental educational attainment and household income are among the primary drivers of individual health, the effects of household SES indicators (for example, parental educational attainment and family income) on health behaviors such as a healthy diet may differ by ethnicity, as discussed by the Marginalization related Diminished Returns (MDRs) phenomenon. Objectives: Built on the MDRs, this study had two aims: first, to test the associations between family SES indicators (parental educational attainment and household income) and diet quality, and second, to test ethnic variation in these associations. Materials and Methods: This longitudinal study used the Adolescent Brain Cognitive Development (ABCD) baseline and year 2 data. Participants included 5,856 individuals who were either Black, White, Latino, or non-Latino. Age, sex, family structure (parental marital status), parental education, and family income were studied. The outcomes were the amount and frequency of consuming fish, soup, vegetables, fruits, hot dogs, French fries, ketchup, soda, and sugary beverages. Linear regression was used for performing the main data analysis. Results: Overall, high educational attainment and family income showed a positive association with fruit consumption and a negative association with the consumption of hot dogs, fries, soda, and sugary beverages in the overall population. We documented statistically significant interactions between ethnicity and educational attainment and household income on our dietary habits of interest, indicating weaker associations between family SES and diet in Black and Latino than non-Latino White individuals. Conclusion: We observe that household SES differently improves the dietary quality of diverse ethnic groups. Due to MDRs of education and income in ethnic minorities, children from highly educated and high-income families eat less healthily than their non-Latino White counterparts. This finding is in line with the MDRs framework that ethnic health disparities sustain across class lines.</jats:p

Racism May Weaken the Brain-Behavior Association among African American Children: The Case of Amygdala Volume-Emotion Regulation Link

Introduction: The amygdala has a central core role in regulating emotions. However, less is known about the racial/ethnic variation in the relevance of amygdala volume for emotion regulation of US children. According to the Minorities’ Diminished Returns (MDRs) phenomenon, due to racism, segregation, and social stratification (rather than innate differences due to genetics), some of the individual-level individual social determinants, could lose some of their relevance for African American (in comparison to White) children. Purpose: Conceptualizing race as a social factor that reflects structural racism and discrimination and building on the MDRs framework, we explored racial variation in the magnitude of the association between amygdala volume and emotion regulation/impulsivity of US children. Methods: For this cross-sectional study, we used baseline data which included behavioral, social, and structural magnetic resonance imaging (MRI) data of 6030 US children ages 9-10. Data came from the Adolescent Brain Cognitive Development (ABCD) study. The primary outcomes were positive and negative urgency. These were measured using Urgency, Premeditation (lack of), Perseverance (lack of), Sensation Seeking, Positive Urgency, and Impulsive Behavior Scale (UPPS-SS) UPPS-SS. The independent variables were right and left amygdala volume. The covariates were age, sex, parental education, household income, parental marital status, neighborhood socioeconomic status, and ethnicity. Race was the moderator. Results: Children with larger amygdala volumes had lower positive and negative urgency. The correlations between amygdala volume and positive and negative urgency were modified by race. For White children, children had better emotion regulation when they had a large amygdala. For African American children, positive and negative urgency did not show an association with amygdala size. Conclusions: The results can be explained by the Minorities’ Diminished Returns (MDRs) hypothesis. In line with MDRs and as a result of structural and interpersonal inequalities, such as school segregation, the amygdala-emotion regulation seen for White children does not replicate for African American children. For White children, however, in the absence of higher-level social determinants, amygdala size correlates with emotion regulation. The brainbehavior link is weaker for African American children whose lives are less predictable and affected by experiences of racial discrimination. Unequal effects of equal resources across racial groups are due to racism and discrimination, not biological innate differences such as genetics.</jats:p

Nieuw Cultureel Burgerschap

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