Analysing mark-recapture-recovery data in the presence of missing covariate data via multiple imputation

We consider mark–recapture–recovery data with additional individual time-varying continuous covariate data. For such data it is common to specify the model parameters, and in particular the survival probabilities, as a function of these covariates to incorporate individual heterogeneity. However, an issue arises in relation to missing covariate values, for (at least) the times when an individual is not observed, leading to an analytically intractable likelihood. We propose a two-step multiple imputation approach to obtain estimates of the demographic parameters. Firstly, a model is fitted to only the observed covariate values. Conditional on the fitted covariate model, multiple “complete” datasets are generated (i.e. all missing covariate values are imputed). Secondly, for each complete dataset, a closed form complete data likelihood can be maximised to obtain estimates of the model parameters which are subsequently combined to obtain an overall estimate of the parameters. Associated standard errors and 95 % confidence intervals are obtained using a non-parametric bootstrap. A simulation study is undertaken to assess the performance of the proposed two-step approach. We apply the method to data collected on a well-studied population of Soay sheep and compare the results with a Bayesian data augmentation approach. Supplementary materials accompanying this paper appear on-line.Publisher PDFPeer reviewe

The Future of California Transportation Revenue

Stable, predictable, and adequate transportation revenues are needed if California is to plan and deliver an excellent transportation system. This report provides a brief history of transportation revenue policies and potential futures in California. It then presents projections of transportation revenue under the recently enacted Senate Bill 1, the Road Repair and Accountability Act of 2017. Those revenue projections are compared with projections of revenue should SB 1 be repealed by voters in the November 2018 election. State-generated transportation revenues will be higher under SB1 than if the act is repealed. For 2020, the mean projection is that the state will collect $10.4 billion with SB1 in place and$6.6 billion without it, a difference of $3.8 billion. Over time, changes in fuel economy and other factors will change annual revenue By 2040, the mean projection is that the state will collect$8.6 billion with SB1 and $3.4 billion without it, a$5.2 billion difference. The total of all state transportation revenue collected between 2018 and 2040, assuming no other revisions to transportation revenue programs during these years, will be about $100 billion less if SB 1 is repealed than if the law is retained. The final section of the report addresses public attitudes toward transportation tax and fee policies, since future any policy changes must be informed by public willingness to consider revenue increases and opinions about which taxes or fees would be most appropriate

The Impact of ZEV Adoption on California Transportation Revenue

Former California Governor Jerry Brown set an ambitious target for the state to reach five million zero-emission vehicles (ZEVs) by 2030. The policy is intended to reduce greenhouse gas emissions, but progress toward this target will also affect future state-generated transportation revenues collected from vehicle owners and operators. A central concern for policymakers is to estimate the magnitude of the revenue impact. We used a simple spreadsheet model to project future transportation revenue in California through 2040 under two scenarios. The first scenario assumes that ZEV ownership continues at its historical rate of net increase, approximately 26,000 vehicles per year (the “low-adoption scenario”). The second scenario assumes that California reaches its goal of five million ZEVs by 2030 (the “high-adoption scenario”). The projections are for light duty vehicles and do not address the possibility that heavy trucks may over time also adopt alternative fuels

The Connection between Personal Traumas and Educational Exclusion in Young People’s Lives

The correlation between young people with poor outcomes and educational exclusion is well documented, but the relationship between the two is taken for granted and remains unexplored. A qualitative longitudinal research project, employing innovative biographic and visual methods, explored this relationship. This article argues that the timing of exclusion is directly related to periods of increased or intense trauma with the transference of emotionality from one domain (personal) to another (educational). This methodological approach enables a distinctive and powerful way of understanding young people’s experiences of exclusion and social change, through the voices of the young people themselves. An original methodological and empirical contribution is made by exploring the unique value of a biographical longitudinal approach focusing on critical moments to understanding young people’s experiences of exclusion; the relationship between multiple traumas in young people’s lives; and how these traumas precipitate exclusion

Caregiver-Child Conversations about Sex in African American Women

Using grounded theory methods, this study examines the experience of African American women during their caregiver-child conversations about sex and the impacts of the conversations on their sexual attitudes. The process of these conversations begins with an unplanned topic and progresses further to identify six essential themes of these conversations: gender differences, race and religion, protective/emphasis on protection, lack of knowledge, withholding knowledge, and sex negativity/shame. African American women’s description of the process included feelings of shame and negativity towards their sexuality. Caregivers promoted positive messages about sex by having open conversations that advocated for equality between the genders, empower women to explore their sexuality, and provide a well-rounded education about all elements surrounding sexuality. The findings from this study will aid clinicians, educators, parents, and communities as a whole to better understand the parts of the conversations that often lead to feelings of shame and negativity surrounding sex and sexuality for African American women

The role of structural disorder in increasing the activity of cobalt oxide and manganese oxide water oxidation catalysts

Hannah King studied catalysts to make renewable hydrogen from water. She found a way to tune the reactivity of catalysts to make them more active. This research can be used to synthesize better catalysts in the future