Portfolio rebalancing with an investment horizon and transaction costs

In this paper we consider the problem of rebalancing an existing financial portfolio, where transaction costs have to be paid if we change the amount held of any asset. These transaction costs can be fixed (so paid irrespective of the amount traded provided a trade occurs) and/or variable (related to the amount traded). We indicate the importance of the investment horizon when rebalancing such a portfolio and illustrate the nature of the efficient frontier that results when we have transaction costs. We model the problem as a mixed-integer quadratic programme with an explicit constraint on the amount that can be paid in transaction cost. Our model incorporates the interplay between optimal portfolio allocation, transaction costs and investment horizon. We indicate how to extend our model to include cardinality constraints and present a number of enhancements to the model to improve computational performance. Results are presented for the solution of publicly available test problems involving up to 1317 assets.     

A Multi-state Piecewise Exponential Model of Hospital Outcomes after Injury

To allow more accurate prediction of hospital length of stay (LOS) after serious injury or illness, a multi-state model is proposed, in which transitions from the hospitalized state to three possible outcome states (home, long-term care, or death) are assumed to follow constant rates for each of a limited number of time periods. This results in a piecewise exponential (PWE) model for each outcome. Transition rates may be affected by time-varying covariates, which can be estimated from a reference database using standard statistical software and Poisson regression. A PWE model combining the three outcomes allows prediction of LOS. Records of 259,941 injured patients from the US Nationwide Inpatient Sample were used to create such a multi-state PWE model with four time periods. Hospital mortality and LOS for patient subgroups were calculated from this model, and time-varying covariate effects were estimated. Early mortality was increased by anatomic injury severity or penetrating mechanism, but these effects diminished with time; age and male sex remained strong predictors of mortality in all time periods. Rates of discharge home decreased steadily with time, while rates of transfer to long-term care peaked at five days. Predicted and observed LOS and mortality were similar for multiple subgroups. Conceptual background and methods of calculation are discussed and demonstrated. Multi-state PWE models may be useful to describe hospital outcomes, especially when many patients are not discharged home.     

Estimating the Reliability of Single-Item Life Satisfaction Measures: Results from Four National Panel Studies

Life satisfaction is often assessed using single-item measures. However, estimating the reliability of these measures can be difficult because internal consistency coefficients cannot be calculated. Existing approaches use longitudinal data to isolate occasion-specific variance from variance that is either completely stable or variance that changes systematically over time. In these approaches, reliable occasion-specific variance is typically treated as measurement error, which would negatively bias reliability estimates. In the current studies, panel data and multivariate latent state-trait models are used to isolate reliable occasion-specific variance from random error and to estimate reliability for scores from single-item life satisfaction measures. Across four nationally representative panel studies with a combined sample size of over 68,000, reliability estimates increased by an average of 16% when the multivariate model was used instead of the more standard univariate longitudinal model.     

Connectivity and Resilience: A Multidimensional Analysis of Infrastructure Impacts in the Southwestern Amazon

Infrastructure is a worldwide policy priority for national development via regional integration into the global economy. However, economic, ecological and social research draws contrasting conclusions about the consequences of infrastructure. We present a synthetic approach to the study of infrastructure, focusing on a multidimensional treatment of indicators of connectivity and resilience. As our study case, we adopt a tri-national frontier in the southwestern Amazon being integrated by a highway, and use survey data for rural leaders to evaluate the relationship of community connectivity to market towns and social-ecological resilience. The findings show varying relationships among different dimensions of connectivity and resilience, which bear implications regarding indicator approaches to the study of infrastructure impacts.     

Building Blocks for a Precautionary Approach to the Use of Nanomaterials: Positions Taken by Trade Unions and Environmental NGOs in the European Nanotechnologies Debate

As partners in the European capacity‐building project NanoCap, trade unions and environmental nongovernmental organizations (NGOs) have established positions on the development of nanotechnologies. Key in their positioning is their view that the use of nanomaterials with currently unknown occupational and environmental hazards must have consequences for the risk management and use of nanoproducts. They have made proposals for responsible manufacturing and for applying the precautionary principle to the use of nanoproducts and they urgently call for the acceptance and the operationalization of a precautionary approach by the industry and governments. The trade unions and NGOs are calling for transparency and openness regarding processes and products that contain nanomaterials and have proposed specific tools for nanomaterial use that put the precautionary principle into practice, including the principles no data → no exposure and no data → no emission. The proposed tools also include compulsory reporting of the type and content of nanoparticles applied in products, a register of workers possibly exposed to nanoparticles, and the use of nano reference values as guides to assess workplace exposure to nanoparticles.     

Implementation of a collaborative model for opioid overdose prevention on campus

Abstract

Drug overdose is the leading cause of death for Americans under the age of 50, a crisis that is driven by an increasingly potent supply of illicit opioids. College-aged adults are more likely than any other age group to engage in opioid misuse. Naloxone, the antidote for an opioid overdose, can save the life of an opioid overdose victim if it is readily available and administered quickly. The University of Texas at Austin implemented a collaborative model for proactive opioid overdose prevention in 2016. This model includes stocking naloxone in residence halls and providing it to police officers, training resident advisors and police officers to respond to suspected overdoses, and engaging student pharmacists in a service learning program to increase naloxone access and awareness among university students. Programmatic experiences and key recommendations for U.S. campuses are shared by faculty, student, and community leaders.     

Comprehensive definitions of breakdown points for independent and dependent observations

Summary. We provide a new definition of breakdown in finite samples, with an extension to asymptotic breakdown. Previous definitions centre on defining a critical region for either the parameter or the objective function. If for a particular outlier configuration the critical region is entered, breakdown is said to occur. In contrast with the traditional approach, we leave the definition of the critical region implicit. Our proposal encompasses previous definitions of breakdown in linear and non-linear regression settings. In some cases, it leads to a different and more intuitive notion of breakdown than other procedures that are available. An important advantage of our new definition is that it also applies to models for dependent observations where current definitions of breakdown typically fail. We illustrate our suggestion by using examples from linear and non-linear regression, and time series.     

家庭结构、重大疾病和农村劳动力迁移

在四川省大样本农户调查数据基础上,利用Probit模型分析了家庭结构特征对农村年轻劳动力迁移的影响。研究发现在控制个人特征的前提下：三代同堂家庭显著支持了年轻劳动力外出,而核心家庭对劳动力的外出有显著负面影响;家庭中有未成年人会限制年轻劳动力的外出;年轻配偶的重大疾病显著地影响了年轻人的外出老年人的严重疾病反而促使年轻劳动力外出,但如果家庭中存在未成年人,则老年人的严重疾病会对年轻劳动力迁移产生显著负面影响。研究结果突出体现了当前中国农村劳动力迁移在很大程度上是一种家庭内部的分工行为,在制定社会保障政策时应该予以重视。     

A children's space? Participation in multi‐agency early intervention

The common assessment framework provides a model of early intervention, which is familiar in local authorities throughout England, and asserts a participatory framework of child and family engagement. This article draws on data from a research project undertaken in 1 local authority in the Midlands of England, to explore the experiences of children, young people, and their families, who were engaged in the process of multi‐agency early intervention. The article considers the young people's involvement, including their accounts of attending common assessment framework meetings, and their engagement by practitioners. The research found that young people's participation was limited. The findings suggest that this is, in part, a response to disciplinary discourses around schooling and attendance. In addition, the narratives of parents and young people showed that under‐resourcing of work with young people meant that the time taken to build relationships and engage them in a process of self‐assessment, planning, and decision making was constrained and rationed. The article concludes that to achieve a participatory children's space, an active and more engaged model of childhood needs to be facilitated by practitioners and parents outside the school‐dominated space found in this study.     

Musculoskeletal symptoms and work ability among agricultural machinery operators

Those subjects whose employment has physical demands present more frequently musculoskeletal symptoms than others. The agricultural sector activities include tasks with important physical demands that may have a negative impact in the workers health. The aim of this study was to evaluate the presence of musculoskeletal symptoms and its association with work ability in agricultural machinery operators. It is a cross-sectional study. The participants (n = 204) answered a self-administered questionnaire on demographics, work and lifestyle characteristics, Work Ability Index and the Nordic Musculoskeletal Symptoms Questionnaire. The response rate was 89.78%. The mean age of the workers was 32.3 years, and 47.1% of them reported musculoskeletal symptoms at least one body part over the past 12 months. Those subjects who presented work ability index <37 points, 87.5% reported some kind of musculoskeletal symptom. This study showed that the work ability was significantly (p ≤ 0.05) correlated to musculoskeletal symptoms presence. It is recommended that measures to promote and improve the work ability are designed and deployed based on musculoskeletal disorders prevention.