Optimal bid-ask price strategies

Economic analysis has begun to focus on the implications of transaction costs to trading in capital assets. Specifically, the economics of market making and the price of liquidity has received considerable attention. This paper formulates the market maker's bid-ask price decision as a semi-Markov decision process with the reward being a function of expected return and risk. Risk is intimately related to dealer inventory and hence the solution of the analysis specifies bid-ask price strategies which are inventory dependent. Numerical examples indicate the market maker's optimal bid-ask prices will tilt around the ‘assets’ equilibrium price to control inventory as well as influence expected profit.     

Geostochastic calculus

A stochastic calculus for a family of continuous measure-valued Markov processes is developed. Such processes arise naturally in the construction of stochastic models of spatially distributed populations. The stochastic calculus is a tool whereby a class of density-dependent models can be studied in terms of the multiplicative measure diffusion process. In this paper the stochastic integral is introduced in the space-time setting and a Cameron-Martin-Girsanov theorem is established.     

Lessons from Drosophila models of DJ-1 deficiency

Mutations in the DJ-1 gene are associated with rare forms of autosomal recessive early-onset Parkinson's disease (PD). Although the precise physiological function of DJ-1 remains obscure, accumulating evidence suggests that DJ-1 may normally function as a redox-sensitive molecular chaperone that can protect against the deleterious effects of oxidative stress, particularly in mitochondria. Recent studies in the fruit fly, Drosophila melanogaster, have shed further light on the biological role of DJ-1. DJ-1-deficient Drosophila models exhibit distinct phenotypes but collectively highlight a prominent neuroprotective role for DJ-1 against oxidative insult. However, Drosophila lacking DJ-1 do not consistently produce a useful PD-like phenotype (that is, they generally fail to exhibit degeneration of neurons that contain the neurotransmitter dopamine), which may reflect putative compensatory neuroprotective mechanisms. DJ-1-deficient fly models further highlight the utility of Drosophila as an important tool for elucidating protein function and for modeling neurodegenerative disease.     

The Social Work Assessment Tool (SWAT)

This paper reports on the last of three National Hospice and Palliative Care Organization initiatives to move hospice and palliative care social workers into the patient/family outcomes arena: the development of the Social Work Assessment Tool. The experience of a team of practitioners and researchers is described, including results of two pilot studies and subsequent SWAT revisions. The major focus is on the current model performance improvement project, in which 19 social workers from 14 hospice and palliative care programs used the SWAT with 101 patients and 81 primary caregivers for a median of 44 days. Quantitative analysis indicated significant improvement in SWAT scores for patients from the first to the second social work visit (t = -2.60, df = 47, p .01). Qualitative interviewing of the social workers indicated some lack of readiness in the field to conduct quantitative outcomes measurement. Additional measures are needed in addition to the SWAT, including qualitative measures, and measures of mezzo and macro practice. Participants indicated that the SWAT was appropriate for use with economically and culturally diverse clients.     

Rural-urban differences in college students’ cardiovascular risk perceptions

Abstract

Objective: To examine rural-urban differences in college students’ cardiovascular risk perceptions. Participants: College students in rural (n?=?61) and urban (n?=?57) Kentucky counties were recruited from November 2012 to May 2014. Methods: This was a secondary data analysis of a cross-sectional study examining rural-urban differences in cardiovascular risk factors. Students rated their risk for developing high blood pressure, diabetes, high cholesterol, heart disease, having a stroke, and gaining excess weight. Chi-square and logistic regression were used for data analysis. Results: Rural students had lower odds of perceived high risk for developing high blood pressure compared to urban students (odds ratio (OR): 0.32, 95% CI: 0.11–0.96) after adjusting for race, sex, and body mass index. This association was not observed after adjusting for healthcare access variables. No other significant differences were observed. Conclusions: Efforts to raise perceived risk for developing hypertension among rural college students may be warranted.     

Modeling time series data with semi-reflective boundaries

Time series data are increasingly common in many areas of the health sciences, and in some instances, may have natural boundaries serving as performance guidelines or as thresholds associated with adverse outcomes. Such boundaries may be labeled as semi-reflective, in that the time series values have an increased chance of returning towards middle levels as the boundaries are approached, but boundaries can still be breached. In this paper we review a model that was previously proposed for such data and we investigate its statistical properties. Specifically, this model consists of a third-order auto-regressive projection component, parameterized as a constrained linear combination of linear, flat, and quadratic trends, and an error term that uses a logistic regression model for its sign. We describe and compare a previously-proposed estimation method with a modified version thereof, using computer simulations, as well as data examples from heart monitoring and from a driving simulator. We find that the two methods tend to give different results, with the modified technique having lower bias and more accurate confidence intervals than the previously-proposed method.     

Understanding Acculturation,Depressive Symptoms,and the Protective Role of Family Involvement Among Latino(a) Immigrant Families

Although the relationship between varying levels of acculturation and depressive symptoms has been established among Latino(a) youth, the positive role of family involvement in relation to depressive symptoms among immigrant Latino(a) families has been studied less. This study draws on a sample of first-generation Latino(a) youth from the Longitudinal Immigrant Student Adaptation Study and explores the relationship between acculturation levels and depressive symptoms, as well as the protective role of family involvement. Although results do not support a relationship between acculturation and depressive symptoms, family involvement was significantly associated with lower depressive symptoms while taking important sociodemographic variables into consideration. Research and practice implications with Latino(a) immigrant families are discussed.