Bradley-Terry models in R : the BradleyTerry2 package

This is a short overview of the R add-on package BradleyTerry2, which facilitates the specification and fitting of Bradley-Terry logit, probit or cauchit models to pair-comparison data. Included are the standard 'unstructured' Bradley-Terry model, structured versions in which the parameters are related through a linear predictor to explanatory variables, and the possibility of an order or 'home advantage' effect or other 'contest-specific' effects. Model fitting is either by maximum likelihood, by penalized quasi-likelihood (for models which involve a random effect), or by bias-reduced maximum likelihood in which the first-order asymptotic bias of parameter estimates is eliminated. Also provided are a simple and efficient approach to handling missing covariate data, and suitably-defined residuals for diagnostic checking of the linear predictor

Questions and Answers About the National Survey of Children\u27s Exposure to Violence.

Presents an overview of the National Survey of Children\u27s Exposure to Violence (NatSCEV), the most comprehensive nationwide survey to date of the incidence and prevalence of children\u27s exposure to violence, sponsored by OJJDP and the Centers for Disease Control and Prevention and carried out by the Crimes Against Children Research Center of the University of New Hampshire. It outlines the survey’s objectives and key features, how exposure to violence was measured, and plans for followup surveys and publications. NatSCEV bases its estimates on a large, nationally representative sample of more than 4,500 children ages 17 and younger. The survey interviewed caregivers of children ages 9 and younger and children and youth ages 10 to 17 about 45 different kinds of violence, abuse, and victimization in the past year and over the course of their lifetime

Children\u27s Exposure to Intimate Partner Violence and Other Family Violence.

Explores in depth the survey results from the National Survey of Children\u27s Exposure to Violence (NatSCEV) regarding exposure to family violence among children in the United States, including exposure to intimate partner violence, assaults by parents on siblings of children surveyed, and other assaults involving teen and adult household members. These results confirm that children are exposed to unacceptable rates of violence in the home. The bulletin presents information regarding the types of exposure to family violence, the gender of the perpetrator, the relationship of the child witness to the perpetrator, and youth\u27s reactions to the incident. It also discusses the implications of the survey data for researchers, practitioners, and policymakers and makes policy recommendations, including better screening protocols for exposure to family violence, improved interventions for those exposed, increased coordination of services for adult and child victims of family violence, and more prevention and education programs to reduce family violence. This is the second in a series of bulletins that present findings from NatSCEV, the most comprehensive nationwide survey to date of the incidence and prevalence of children’s exposure to violence across all ages, settings, and timeframes

Child and Youth Victimization Known to Police, School, and Medical Authorities.

Presents the survey results from the National Survey of Children\u27s Exposure to Violence (NatSCEV) regarding authorities\u27 knowledge of victimization incidents involving children and youth, particularly police, school, and medical authorities. Compared with a similar study in the early 1990s, the survey found that authorities were more likely to know about NatSCEV survey participants\u27 exposure to violence, which may reflect efforts by authorities, criminal justice and child protection agencies, and advocates to promote disclosure. This increase in disclosure is also consistent with the decrease in child victimizations during the last two decades. The survey found that 46 percent of children who were victimized in the previous year had at least one victimization known to school, police, and medical authorities, with school authorities (e.g., teachers, principals, and counselors) being the most likely to know of the victimizations. However, police were most likely to know about many of the most serious victimizations. In general, authorities were most likely to know about serious victimizations, including sexual abuse by an adult, kidnapping, and gang or group assaults. They were least likely to know about victimizations committed by other youth, including peer and sibling assaults, dating violence, flashing, and completed or attempted rate. This bulletin also discusses factors that promote or hinder disclosure of victimization incidents to authorities, and the implications of the increase in disclosure for prevention and treatment. This is the fourth in a series of bulletins that present findings from NatSCEV, the most comprehensive nationwide survey to date of the incidence and prevalence of children’s exposure to violence across all ages, settings, and timeframes

Polyvictimization: Children\u27s Exposure to Multiple Types of Violence, Crime, and Abuse.

Presents the findings of the National Survey of Children\u27s Exposure to Violence (NatSCEV) regarding children\u27s direct exposure to multiple types of violence, crime, and abuse, also known as polyvictimization. Children and youth who are exposed to multiple types of violence are at particularly high risk for lasting physical, mental, and emotional harm, even compared with children who experience repeated exposures to a single type of violence. Among the key findings: 8 percent of all youth in the nationally representative NatSCEV sample had seven or more different kinds of exposures to violence, crime, and abuse in the past year. These youth also had a disproportionate share of the most serious kinds of victimizations, such as sexual victimization and parental maltreatment. Polyvictimization was most likely to start near the beginning of grade school and the beginning of high school and tended to persist over time. It was associated with a cluster of four prior circumstances or pathways: living in a violent family, living in a distressed and chaotic family, living in a violent neighborhood, and having preexisting psychological symptoms. In addition, polyvictims are overrepresented among certain demographic groups, including boys, African American children, and children in single-parent, stepparent, and other adult caregiver families. This is the third in a series of bulletins that present findings from NatSCEV, the most comprehensive nationwide survey to date of the incidence and prevalence of children\u27s exposure to violence across all ages, settings, and timeframes

Cellular and genetic bases of cold nociception and nociceptive sensitization in Drosophila larvae

Organisms from flies to mammals utilize thermoreceptors to detect and respond to noxious thermal stimuli. Although much is understood about noxious heat avoidance, our understanding of the basic biology of noxious cold perception is gravely minimal. Numerous clinical conditions disrupt the sensory machinery, such as in patients suffering from tissue damage (from wound or sunburn), or injury to the peripheral nerves, as in patients with diabetes or undergoing chemotherapy. Our goal is to determine the genetic basis for noxious cold perception and injury-induced nociceptive sensitization using the genetically tractable Drosophila model. Using a novel cold probe tool and assay we found larvae produce a mutually exclusive set of reactive behaviors to a defined noxious cold stimulus (3-12 ºC), including a full-body contraction and the bending of anterior and posterior segments to make a U-Shape. These behaviors are distinct from normal locomotion, responses to gentle touch, noxious heat or harsh mechanical stimuli. Through genetic manipulation, we found cold responses require specific classes of peripheral sensory neurons and receptors, which differ depending on the cold-evoked behavior. Our data indicates these cold-sensing neurons are multimodal, and the level of cellular activation determines the behavioral output to different stimuli. To study cold nociceptive sensitization, we used a sunburn assay which exposes the dorsal side of the larva to UV-damage, and found larvae display a dramatic shift in cold responses after injury. This behavioral shift requires similar sets of peripheral sensory neurons and receptors specific to each sensitized cold-evoked behavior. Lastly, we found the Tumor Necrosis Factor (TNF) and Tachykinin (Tk) pathways, both involved in sensitization to noxious heat, may also play a role UV-induced cold sensitization. We have established the first system to study noxious cold and cold sensitization in Drosophila. Our unique tool and assay will allow us to further uncover the conserved molecular and genetic players involved in this process

I\u27m still valid: an explanatory sequential mixed-methods study of part-time phd students\u27 motivation and satisfaction.

Doctoral attrition rates are consistently documented at approximately 50% in the United States, and attrition rates are typically higher for all students who pursue degrees on a part-time basis, regardless of degree level. Yet an increasing number of students are deciding to pursue research doctorates on a part-time basis. This growth in the part-time PhD student population requires an understanding of the factors that affect their persistence. I investigated part-time PhD student persistence through an explanatory sequential mixed methods approach to understanding the relationship between motivation and satisfaction through the lens of Self-Determination Theory. Findings suggest that part-time PhD students are motivated by knowledge advancement and relationships with others, yet they may be lacking in access to community in ways that contribute to negative outcomes physically, psychologically, and intellectually. Like many doctoral students, they are demotivated when they feel isolated, exhausted, and overwhelmed; part-time enrollment exacerbates these feelings. Motivation to enroll part-time is largely dictated by family circumstances (e.g., financial need, caregiving responsibilities) and a desire for career advancement. Like motivation, satisfaction is primarily derived through relationships with others, feeling supported, and personal and professional growth. However, a lack of community access inhibits part-time student socialization, and may lead to untested assumptions regarding faculty roles and the purpose of research doctoral education. Additionally, part-time students appear reticent to report feelings of overall dissatisfaction, despite indicating feeling dissatisfied with many components of the doctoral experience. Implications for research and practice are discussed

Modelling rankings in R: the PlackettLuce package

This paper presents the R package PlackettLuce, which implements a generalization of the Plackett-Luce model for rankings data. The generalization accommodates both ties (of arbitrary order) and partial rankings (complete rankings of subsets of items). By default, the implementation adds a set of pseudo-comparisons with a hypothetical item, ensuring that the underlying network of wins and losses between items is always strongly connected. In this way, the worth of each item always has a finite maximum likelihood estimate, with finite standard error. The use of pseudo-comparisons also has a regularization effect, shrinking the estimated parameters towards equal item worth. In addition to standard methods for model summary, PlackettLuce provides a method to compute quasi standard errors for the item parameters. This provides the basis for comparison intervals that do not change with the choice of identifiability constraint placed on the item parameters. Finally, the package provides a method for model-based partitioning using covariates whose values vary between rankings, enabling the identification of subgroups of judges or settings that have different item worths. The features of the package are demonstrated through application to classic and novel data sets.Comment: In v2: review of software implementing alternative models to Plackett-Luce; comparison of algorithms provided by the PlackettLuce package; further examples of rankings where the underlying win-loss network is not strongly connected. In addition, general editing to improve organisation and clarity. In v3: corrected headings Table 4, minor edit