Entropy for random group actions

We consider the entropy of systems of random transformations, where the transformations are chosen from a set of generators of a Z d action. We show that the classical denition gives unsatisfactory entropy results in the higher-dimensional case, i.e. when d 2. We propose a denition of the entropy for random group actions which agrees with the classical denition in the one-dimensional case, and which gives satisfactory results in higher dimensions. This denition is based on the bre entropy of a certain skew product. We identify the entropy by an explicit formula which makes it possible to compute the entropy in certain cases

Initial Public Offerings: The Case Of Health Maintenance Organizations (HMOs)

Objective: To determine whether the returns of initial public offerings (IPOs) of HMOs in the days following issue are similar to the return behavior of IPOs in previous studies.Data Source: The Center for Research in Security Prices (CRSP) tapes compiled by the Graduate School of Business at the University of Chicago provides daily stock prices, holding period returns, and other data pertinent to research in traded securities.Study Design: The hypothesis to be tested is whether the mean excess return surrounding the offer date is equal to zero.  To adjust the initial returns of the IPOs for overall market movements, Standard & Poor’s Composite Index (S&P 500) was selected as the proxy for the market in general.  We compute the long-run performance for the HMOs and compare that return to the S&P 500 and the CRSP AMEX/NYSE equally-weighted and value-weighted indices.Data Collection/Extraction Method:  We matched for-profit HMOs listed in the National Directory of Managed & Integrated Care Organizations to the commitment offerings reported by Securities Data Corporation to the same firms on the daily CRSP tapes.  This left 49 firms that went public between 1971 through 1997.  The Wharton Research and Data Services External (WRDSX) was used for data extraction and SAS was used for statistical analysis.Principal Findings: IPOs of HMOs are underpriced and demonstrate abnormal returns.  The average initial return on these IPOs is less than that of the average in the United States.  On a long-run performance basis, they performed better than the broad market indices.Conclusions:  Returns follow a similar pattern as do IPOs in general except for the long-run performance.  This needs further research as well as a comparison of performance before and after going public in cases where accounting data is available

Facial emotion recognition in refugee children with a history of war trauma.

Over 36 million children are currently displaced due to war, yet we know little about how these experiences of war and displacement affect their socioemotional development-notably how they perceive facial expressions. Across three different experiments, we investigated the effects of war trauma exposure on facial emotion recognition in Syrian refugee (n = 130, Mage = 9.3 years, 63 female) and Jordanian nonrefugee children (n = 148, Mage = 9.4 years, 66 female) living in Jordan (data collected 2019-2020). Children in the two groups differed in trauma exposure, but not on any of our measures of mental health. In Experiment 1, we measured children's biases to perceive an emotion using morphed facial expressions and found no evidence that biases differed between refugees and nonrefugees. In Experiment 2, we adapted a novel perceptual scaling task that bypasses semantic knowledge, and again found no differences between the two group's discrimination of facial expressions. Finally, in Experiment 3, we recorded children's eye movements as they identified Middle Eastern actors' facial expressions, and again found no differences between the groups in either their identification accuracies or scanning strategies. Taken together, our results suggest that exposure to war-related trauma and displacement during early development, when reported by the caregiver but not always recollected by the child, does not appear to alter emotion recognition of facial expressions. (PsycInfo Database Record (c) 2023 APA, all rights reserved)

Maternal Trauma and Psychopathology Symptoms Affect Refugee Children's Mental Health But Not Their Emotion Processing.

Refugee children's development may be affected by their parents' war-related trauma exposure and psychopathology symptoms across a range of cognitive and affective domains, but the processes involved in this transmission are poorly understood. Here, we investigated the impact of refugee mothers' trauma exposure and mental health on their children's mental health and attention biases to emotional expressions. In our sample of 324 Syrian refugee mother-child dyads living in Jordan (children's Mage=6.32, SD = 1.18; 50% female), mothers reported on their symptoms of anxiety and depression, and on their children's internalising, externalising, and attention problems. A subset of mothers reported their trauma exposure (n = 133) and PTSD symptoms (n = 124). We examined emotion processing in the dyads using a standard dot-probe task measuring their attention allocation to facial expressions of anger and sadness. Maternal trauma and PTSD symptoms were linked to child internalising and attention problems, while maternal anxiety and depression symptoms were associated with child internalising, externalising, and attention problems. Mothers and children were hypervigilant towards expressions of anger, but surprisingly, mother and child biases were not correlated with each other. The attentional biases to emotional faces were also not linked to psychopathology risk in the dyads. Our findings highlight the importance of refugee mothers' trauma exposure and psychopathology on their children's wellbeing. The results also suggest a dissociation between the mechanisms underlying mental health and those involved in attention to emotional faces, and that intergenerational transmission of mental health problems might involve mechanisms other than attentional processes relating to emotional expressions

Cantor type functions in non-integer bases

Cantor's ternary function is generalized to arbitrary base-change functions in non-integer bases. Some of them share the curious properties of Cantor's function, while others behave quite differently

Urban transportation: Perspectives on mobility and choice

A study of urban transportation systems are presented characterized by intensive scrutiny of many ideas, philosophies, and academic perspectives. This report is intended to communicate some dimensions of the urban transportation problem to the general public

Predictors of Literacy and Attitudes Toward Reading Among Syrian Refugee Children in Jordan

Refugee children often face disruptions to their education before and during displacement. However, little is known about either levels or predictors of refugee children’s literacy or about their attitudes toward reading in low- or middle-income countries. To address this, we conducted in-home literacy assessments using the Holistic Assessment of Learning and Development Outcomes with 322 Syrian refugee mother–child dyads who lived in Jordan (child age range 4–8 years, M = 6.32 years, 50% female). Overall, the children had quite low levels of literacy, although they indicated a strong enthusiasm for reading. Child age, maternal education, and maternal ability to read all predicted child literacy, although maternal literacy predicted it only among children enrolled in school. Among those enrolled in school (64.9% of the total sample, 88.7% of those aged ≥ 6), students attending hybrid classes had better literacy than those attending either solely in-person or solely online, although the frequency of school attendance did not predict literacy. A less consistent pattern emerged for predicting children’s attitudes toward reading. Our results suggest an urgent need to improve literacy skills among refugee children in Jordan, as well as a need for validated measures of attitudes toward reading for use with Arabic-speaking youth. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13158-022-00334-x

FAAH, SLC6A4, and BDNF variants are not associated with psychosocial stress and mental health outcomes in a population of Syrian refugee youth

The developmental origins of health and disease (DOHaD) hypothesis posits that early childhood stressors disproportionately impact adult health. Numerous studies have found adult mental health to be associated with childhood adversities and genetic variants, particularly in genes related to neurochemistry. However, few studies have examined the way interactive effects may manifest over time and fewer still include protective factors, like resilience. Our group has previously found associations between the monoamine oxidase A gene, MAOA, and a contextually-specific measure of resilience with a measure of perceived psychosocial stress over time in Syrian refugee youth. In this study, we work with the same sample of adolescents to test genetic variants in three additional candidate genes (FAAH, the 5-HTTLPR region of SLC6A4, and BDNF) for associations with six psychosocial stress and mental health outcomes. Using multi-level modeling, we find no association between variants in these candidate genes and psychosocial stress or mental health outcomes. Our analysis included tests for both direct genetic effects and interactions with lifetime trauma and resilience. Negative results, such as the lack of genetic associations with outcome measures, provides a more complete framework in which to better understand positive results and associations

Human Breathing Rate Estimation from Radar Returns Using Harmonically Related Filters

Radar-based noncontact sensing of life sign signals is often used in safety and rescue missions during disasters such as earthquakes and avalanches and for home care applications. The radar returns obtained from a human target contain the breathing frequency along with its strong higher harmonics depending on the target’s posture. As a consequence, well understood, computationally efficient, and the most popular traditional FFT-based estimators that rely only on the strongest peak for estimates of breathing rates may be inaccurate. The paper proposes a solution for correcting the estimation errors of such single peak-based algorithms. The proposed method is based on using harmonically related comb filters over a set of all possible breathing frequencies. The method is tested on three subjects for different postures, for different distances between the radar and the subject, and for two different radar platforms: PN-UWB and phase modulated-CW (PM-CW) radars. Simplified algorithms more suitable for real-time implementation have also been proposed and compared using accuracy and computational complexity. The proposed breathing rate estimation algorithms provide a reduction of about 81% and 80% in the mean absolute error of breathing rates in comparison to the traditional FFT-based methods using strongest peak detection, for PN-UWB and PM-CW radars, respectively