The Impact of Density: The Importance of Nonlinearity and Selection on Flight and Fight Responses

Unlike commonsense notions and the findings from animal research, the literature concerning the effects of density on human social behavior is paralyzed by contradictory findings. This article examines empirically two fundamental issues which could account for this and which are central to the density-crowding debate: (1) whether observed crowding effects are the result of causation or selection and (2)whether individuals are negatively affected by both low and high levels of density. Data from the Toronto Mental Health and Stress study are analyzed using structural equation modeling to investigate these questions. The results support the notion that the effects of density on aggressive and withdrawn behavior are nonlinear in nature. The findings further reveal a self-selection of respondents into particular forms of housing. The implications of these findings for future research on crowding are discussed

When Context Matters: A Multilevel Analysis of Household and

Studies examining the effects of density and crowding on human social behaviour have produced inconsistent results. This paper argues that among the reasons for these varied findings are: (1) the failure of researchers to examine how the level of density in the wider contextual environment influences the nature of the relationship between household density and social behaviour; (2) the tendency of past studies to overlook the negative consequences of both very low and very high levels of density; and (3) a lack of research investigating whether multiple coping strategies to high-density environments may be invoked by a single individual. Data from the Toronto Mental Health and Stress study are analysed using hierarchical nonlinear modelling to assess the interaction between household and neighbourhood density effects on aggression and withdrawal. The results support the notion that the effects of density on aggressive and withdrawn behaviour are nonlinear in nature and that the impact of household density is conditional on neighbourhood density. The implications of these findings for future research on density are discussed

Adolescent Violent Victimization and Offending: Assessing the Extent of the Link

This article discusses the association between adolescent violent victimization and offending. A key issue in understanding both criminal offending and victimization concerns victim-offender relationships. Research on crime, particularly violent offenses, requires examining the interpersonal relationships which exist among victims and offenders. Nevertheless, those studies which disaggregate crime rates by victim-offender relationships have essentially confined their analyses to adults. This coincides with a more general trend in criminological research on adolescents to confine analyses to offending behavior. Consequently, there is a dearth research on adolescents and youth victims, particularly with respect to the individuals most likely to offend against them. Within the last decade researchers have made a concerted effort to offset this previous neglect of adolescent victimization. That is, that those adolescents who are at greatest risk of being victimized are individuals who engage in delinquent activities themselves, and, consequently, that adolescent victims and offenders cannot be classified solely in terms of membership. Although their specific explanations vary, a number of criminological theories may be interpreted as predicting an overlap in victim-offender populations, including routine activities and the subculture of violence theory

Metabolic stability of the fucose in rat transferrin

AbstractThe metabolic behaviour of the chitobiose core fucose that is a natural constituent of a large proportion of rat transferrin molecules was studied in rats comparatively to that of the polypeptide portion of the glyco-protein by using appropriate labels ([3H]fucose and 125I) and affinity chromatographic techniques (lentil-Sepharose). No evidence was obtained to suggest that this residue is cleaved from the glycan in significant amounts before removal of the entire glycoprotein for catabolism. Similarly, [14C]fucose linked to GlcNAc residues in the antennae of human asialotransferrin was being eliminated in pigeons at the same rate as the polypeptide itself. It is concluded that in spite of transferrin's exposure to the cellular milieu, the fate of its fucose is distinctly different from that of the same in plasma membrane glycoproteins

A Case-by-Case Comparison of the Classification of Law Enforcement and Vital Statistics Data on Homicide

This study uses data from the California Linked Homicide File as a basis for evaluating the validity and reliability of homicide data. Case-by-case comparisons of variables reported by both agencies indicate that agreement between law enforcement and vital statistics data is highest with classifying homicides and victim gender and race and lowest with classifying victim age, manslaughters, and police justifiable homicides. The findings from a multilevel analysis examining what types of cases are unable to be linked over the two data-collection systems reveal that homicides involving Hispanic victims, weapons other than handguns, and family members other than intimate partners and homicides involving felonies, other nonfelonies, and negligent manslaughters have a greater likelihood of not being matched across the agencies. Death investigation systems that use medical examiners also decrease matching. The need for qualitative research examining how classification decisions are made by police and medical examiners or coroners is discussed

Missing Data in Homicide Research

This article is an introduction to the special issue of Homicide Studies on missing data. The first section is an overview of the status of missing data approaches in homicide research. It begins by describing the importance of missing data estimation in homicide. This is followed by a discussion of missing data mechanisms, complete case analysis, imputation and weighting, and model-based procedures. The second section is a brief description of each of the articles in this issue. The conclusion describes the myth associated with imputing missing data, the use of missing data approaches in public records, the Supreme Court case that found hot-deck imputation acceptable for the census, and guidelines for handling missing data published by the American Psychological Association. This section concludes by describing the kinds of research that need to be done

The Application of Missing Data Estimation Models to the Problem of Unknown Victim/Offender Relationships in Homicide Cases.

Homicide cases suffer from substantial levels of missing data, a problem largely ignored by criminological researchers. The present research seeks to address this problem by imputing values for unknown victim/offender relationships using the EM algorithm. The analysis is carried out first using homicide data from the Los Angeles Police Department (1994-1998), and then compared with imputations using homicide data for Chicago (1991-1995), using a variety of predictor variables to assess the extent to which they influence the assignment of cases to the various relationship categories. The findings indicate that, contrary to popular belief, many of the unknown cases likely involve intimate partners, other family, and friends/acquaintances. However, they disproportionately involve strangers. Yet even after imputations, stranger homicides do not increase more than approximately 5%. The paper addresses the issue of whether data on victim/offender relationships can be considered missing at random (MAR), and the im-plications of the current findings for both existing and future research on homicide

Murder Clearance Rates: Guest Editors\u27 Introduction

The journal Homicide Studies has long been devoted to empirical studies addressing issues pertinent to the study of homicide and violence. Although a large variety of theoretical papers, research summaries, and public policy reviews of issues concerning homicide and violence have been explored in the journal over the past 10 years, at least one issue has garnered relatively little attention—the law enforcement response to homicide. This special issue attempts to begin filling this gap in the literature

Taking on the Unknown: A Qualitative Comparative Analysis of Unknown Relationship Homicides

Aside from noting the dramatic rise in their numbers, homicides with unknown victim/offender relationships have attracted little research attention. This study uses Qualitative Comparative Analysis and data from the Supplementary Homicide Reports for 1976 through 1998 to examine the nature of unknown relationship homicides and changes in their structure over time. The findings indicate that a large number of unknown relationship cases are contained within a few prevalent homicide situations while also occurring in a diverse array of less common situations. The situational context of unknown homicides exhibits considerable change over time, shifting from the killing of older White males with a variety of weapons to killings involving young Black males with guns. Although unknown and stranger homicides frequently share common structures, they demonstrate notable differences as well, suggesting that unknown relationships cannot automatically be assumed to involve strangers. Implications of the findings for policy and future research are discussed

The Application of Missing Data Estimation Models to the Problem of Unknown Victim/Offender Relationships in Homicide Cases.

Homicide cases suffer from substantial levels of missing data, a problem largely ignored by criminological researchers. The present research seeks to address this problem by imputing values for unknown victim/offender relationships using the EM algorithm. The analysis is carried out first using homicide data from the Los Angeles Police Department (1994-1998), and then compared with imputations using homicide data for Chicago (1991-1995), using a variety of predictor variables to assess the extent to which they influence the assignment of cases to the various relationship categories. The findings indicate that, contrary to popular belief, many of the unknown cases likely involve intimate partners, other family, and friends/acquaintances. However, they disproportionately involve strangers. Yet even after imputations, stranger homicides do not increase more than approximately 5%. The paper addresses the issue of whether data on victim/offender relationships can be considered missing at random (MAR), and the im-plications of the current findings for both existing and future research on homicide