Sociometric network analysis in illicit drugs research: A scoping review.

BACKGROUND: Sociometric or whole network analysis, a method used to analyze relational patterns among social actors, emphasizes the role of social structure in shaping behaviour. Such method has been applied to many aspects of illicit drug research, including in the areas of public health, epidemiology, and criminology. Previous reviews about social networks and drugs have lacked a focus on the use of sociometric network analysis for illicit drugs research across disciplines. The current scoping review aimed to provide an overview of the sociometric network analysis methods used in illicit drugs research and to assess how such methods could be used for future research. METHODS: A systematic search of six databases (Web of Science, ProQuest Sociology Collection, Political Science Complete, PubMed, Criminal Justice Abstracts, and PsycINFO) returned 72 relevant studies that met the inclusion criteria. To be included, studies had to mention illicit drugs and use whole social network analysis as one of their methods. Studies were summarized quantitatively and qualitatively using a data-charting form and a description of the studies' main topics. RESULTS: Sociometric network analysis in illicit drugs research has grown in popularity in the last decade, using mostly descriptive network metrics, such as degree centrality (72.2%) and density (44.4%). Studies were found to belong to three study domains. The first, drug crimes investigated network resilience and collaboration patterns in drug trafficking networks. The second domain, public health, focused on the social networks and social support of people who use drugs. Finally, the third domain focused on the collaboration networks of policy, law enforcement, and service providers. CONCLUSION: Future illicit drugs research using whole network SNA should include more diverse data sources and samples, incorporate mixed and qualitative methods, and apply social network analysis to study drug policy.

Network Integration within a Prison-Based Therapeutic Community.

Prison-based therapeutic communities (TCs) are a widespread, effective way to help incarcerated individuals address substance abuse problems. The TC philosophy is grounded in an explicitly relational paradigm that entails building community and conditioning residents to increasingly take responsibility for leadership therein. Although TCs are based on cultivating a network that continuously integrates new residents, many common structural features can jeopardize TC goals and are hence discouraged (e.g., clustering, homophily). In light of this tension, analyzing the TC from a network perspective can offer new insights to its functioning, as well as to broader questions surrounding how networks integrate new members. In this study we examine a men's TC unit in a Pennsylvania prison over a 10-month span. Using data on residents' informal networks, we examine: (1) how well individuals integrate into the TC network across time, (2) what predicts how well residents integrate into the TC, and (3) how well the TC network structure adheres to theoretical ideals. Results suggest that individual integration is driven by a range of hypothesized factors and, with limited exceptions, the observed TC is able to foster a network structure and integrate residents consistent with TC principles. We discuss the implications of these results for evaluating TCs and for understanding the process of network integration.

A Network Approach to Understanding the Structure of Core Symptoms of Psychopathic Personality Disturbance in Adolescent Offenders.

A central aim of research on psychopathic personality disturbance (PPD) involves identifying core features of the construct. This has been addressed primarily through prototypicality studies and research using item-response theory. More recently, the logic of social network analysis was extended to psychopathology research to examine which symptoms were most central to PPD networks. Such studies identified affective symptoms of the disorder as especially central among adult offenders. To build upon this prior research, the current study used data on male offenders from the Incarcerated Serious and Violent Young Offender Study to examine the network structure of the Comprehensive Assessment of Psychopathic Personality - Institutional Rating Scale (CAPP-IRS; n = 224) and Psychopathy Checklist: Youth Version (PCL:YV; n = 445). Using multiple measures of PPD helped avoid equating measures with constructs. In both the CAPP-IRS and PCL:YV networks, in line with prior studies, attachment/affective features of the disorder were most central. Several recommendations are made for future research, including the need to study the longitudinal development of PPD using a network approach.

Back to the core: A network approach to bolster harm reduction among persons who inject drugs.

BACKGROUND: Injecting drugs safely almost always includes the presence of one's social network, especially for the prevention of overdose. Yet, the systematic analysis of users' social networks has yet to be established as a focal method in harm reduction research, and interventions. METHODS: This study draws from 200 interviews with persons who inject drugs recruited from North America's first sanctioned supervised injection facility and a drug user's advocacy group. Respondents were asked about the individuals they personally considered as facilitators of harm reduction, and the relations between them. Collectively, these 200 respondents provided over 900 individuals whom they considered as members of their harm reduction network. The aim was to locate individuals that would potentially make the network denser (harm reduction champions) and users that were situated in the "periphery" of the network, and in practice, further away from the harm reduction core. RESULTS: Of the 1135 network members, 63 individuals formed the "core" of the harm reduction network, collectively reaching approximately 70% of individuals in the network. We also uncovered 31 individuals that acted as "articulation points"- these individuals were not as connected, but were more effective at reaching peripheral individuals. CONCLUSION: Former or current injecting drug users that were sampled were surrounded by a relatively rich harm reduction network, but the network approach showed that only a minority of individuals were true harm reduction "champions". Recruitment of a combination of well-connected harm reduction champions, and strategically connected articulation points, would be most effective in planning network interventions that encourage harm reduction behaviors among this population.

Assessing the Validity of Automated Webcrawlers as Data Collection Tools to Investigate Online Child Sexual Exploitation.

The distribution of child sexual exploitation (CE) material has been aided by the growth of the Internet. The graphic nature and prevalence of the material has made researching and combating difficult. Although used to study online CE distribution, automated data collection tools (e.g., webcrawlers) have yet to be shown effective at targeting only relevant data. Using CE-related image and keyword criteria, we compare networks starting from CE websites to those from similar non-CE sexuality websites and dissimilar sports websites. Our results provide evidence that (a) webcrawlers have the potential to provide valid CE data, if the appropriate criterion is selected; (b) CE distribution is still heavily image-based suggesting images as an effective criterion; (c) CE-seeded networks are more hub-based and differ from non-CE-seeded networks on several website characteristics. Recommendations for improvements to reliable criteria selection are discussed.

Where "Old Heads" Prevail: Inmate Hierarchy in a Men's Prison Unit.

Research of inmate social order is a once-vibrant area that receded just as American incarceration rates climbed and the country's carceral contexts dramatically changed. This study reengages inmate society with an abductive mixed methods investigation of informal status within a contemporary men's prison unit. The authors collect narrative and social network data from 133 male inmates housed in a unit of a Pennsylvania medium-security prison. Analyses of inmate narratives suggest that unit "old heads" provide collective goods in the form of mentoring and role modeling that foster a positive and stable peer environment. This hypothesis is then tested with Exponential Random Graph Models (ERGMs) of peer nomination data. The ERGM results complement the qualitative analysis and suggest that older inmates and those who have been on the unit longer are perceived by their peers as powerful and influential. Both analytical strategies point to the maturity of aging and the acquisition of local knowledge as important for attaining informal status in the unit. In sum, this mixed methods case study extends theoretical insights of classic prison ethnographies, adds quantifiable results capable of future replication, and points to a growing population of older inmates as important for contemporary prison social organization.

TOWARD A CRIMINOLOGY OF INMATE NETWORKS.

The mid-twentieth century witnessed a surge of American prison ethnographies focused on inmate society and the social structures that guide inmate life. Ironically, this literature virtually froze in the 1980s just as the country entered a period of unprecedented prison expansion, and has only recently begun to thaw. In this manuscript, we develop a rationale for returning inmate society to the forefront of criminological inquiry, and suggest that network science provides an ideal framework for achieving this end. In so doing, we show that a network perspective extends prison ethnographies by allowing quantitative assessment of prison culture and illuminating basic characteristics of prison social structure that are essential for improving inmate safety, health, and community reentry outcomes. We conclude by demonstrating the feasibility and promise of inmate network research with findings from a recent small-scale study of a maximum-security prison work unit.

Liking and hyperlinking: Community detection in online child sexual exploitation networks.

The online sexual exploitation of children is facilitated by websites that form virtual communities, via hyperlinks, to distribute images, videos, and other material. However, how these communities form, are structured, and evolve over time is unknown. Collected using a custom-designed webcrawler, we begin from known child sexual exploitation (CE) seed websites and follow hyperlinks to connected, related, websites. Using a repeated measure design we analyze 10 networks of 300 + websites each - over 4.8 million unique webpages in total, over a period of 60 weeks. Community detection techniques reveal that CE-related networks were dominated by two large communities hosting varied material -not necessarily matching the seed website. Community stability, over 60 weeks, varied across networks. Reciprocity in hyperlinking between community members was substantially higher than within the full network, however, websites were not more likely to connect to homogeneous-content websites.

Lessons from conducting trans-national Internet-mediated participatory research with hidden populations of cannabis cultivators.

BACKGROUND: Internet-mediated research methods are increasingly used to access hidden populations. The International Cannabis Cultivation Questionnaire (ICCQ) is an online survey designed to facilitate international comparisons into the relatively under-researched but increasingly significant phenomenon of domestic cannabis cultivation. The Global Cannabis Cultivation Research Consortium has used the ICCQ to survey over 6000 cannabis cultivators across 11 countries. In this paper, we describe and reflect upon our methodological approach, focusing on the digital and traditional recruitment methods used to access this hidden population and the challenges of working across multiple countries, cultures and languages. METHODS: Descriptive statistics showing eligibility and completion rates and recruitment source by country of residence. RESULTS: Over three quarters of eligible respondents who were presented with the survey were included in the final sample of n=6528. English-speaking countries expended more effort to recruit participants than non-English-speaking countries. The most effective recruitment modes were cannabis websites/groups (33%), Facebook (14%) and news articles (11%). While respondents recruited through news articles were older, growing practice variables were strikingly similar between these main recruitment modes. CONCLUSION: Through this process, we learnt that there are trade-offs between hosting multiple surveys in each country vs. using one integrated database. We also found that although perceived anonymity is routinely assumed to be a benefit of using digital research methodologies, there are significant limits to research participant anonymity in the current era of mass digital surveillance, especially when the target group is particularly concerned about evading law enforcement. Finally, we list a number of specific recommendations for future researchers utilising Internet-mediated approaches to researching hidden populations.

Global patterns of domestic cannabis cultivation: sample characteristics and patterns of growing across eleven countries.

BACKGROUND: This article aims to provide an overview of: demographic characteristics; experiences with growing cannabis; methods and scale of growing operations; reasons for growing; personal use of cannabis and other drugs; participation in cannabis and other drug markets; contacts with the criminal justice system for respondents to an online survey about cannabis cultivation drawn from eleven countries (N=6530). Important similarities and differences between the national samples recruited will be discussed. METHODS: This paper utilizes data from the online web survey of predominantly 'small-scale' cannabis cultivators in eleven countries conducted by the Global Cannabis Cultivation Research Consortium (GCCRC). Here we focus primarily on descriptive statistics to highlight key similarities and differences across the different national samples. RESULTS: Overall there was a great deal of similarity across countries in terms of: demographic characteristics; experiences with growing cannabis; methods and scale of growing operations; reasons for growing; use of cannabis and other drugs; participation in cannabis and other drug markets, and; contacts with the criminal justice system. In particular, we can recognise that a clear majority of those small-scale cannabis cultivators who responded to our survey are primarily motivated for reasons other than making money from cannabis supply and have minimal involvement in drug dealing or other criminal activities. CONCLUSIONS: These growers generally come from 'normal' rather than 'deviant' backgrounds. Some differences do exist between the samples drawn from different countries suggesting that local factors (political, geographical, cultural, etc.) may have some influence on how small-scale cultivators operate, although differences in recruitment strategies in different countries may also account for some differences observed.

Production, perceptions, and punishment: restrictive deterrence in the context of cannabis cultivation.

BACKGROUND: American authorities have invested extraordinary resources to keep up with the growth in cannabis cultivation, and state-level cannabis laws have been changing rapidly. Despite these changes, little research on the relationship between criminal justice sanctions and grower behaviours exist, in particular research that examines restrictive deterrence - the altering of an illegal behaviour as opposed to desisting from it completely. METHODS: We examine restrictive deterrence in the context of cannabis cultivation by modelling the relationship between the threat of sanctions and the size of cultivation site and number of co-offenders. We use data from an anonymous web survey where participants were recruited through advertisements on websites related to cannabis use and cultivation. Negative binomial regression were used on 337 cases that contain valid data on size of cultivation site and 338 cases that contain valid data on the number of co-offenders. RESULTS: Our study found some evidence that the severity of state sanctions reduces the size of cultivation sites among growers who reside in the state. However, the number of contacts with the police had the opposite effect. In addition, we did not find a restrictive deterrent effect for the number of co-offenders, suggesting that different factors affect different decision points. Interestingly, objective skill and subjective skill had positive and independent effects on size of site. CONCLUSIONS: Results suggest that state-level sanctions have a structuring effect by restricting the size of cultivation sites but further increases in sanctions or enforcement are unlikely to deter more individuals from growing cannabis. In fact, there may be some potential dangers of increased enforcement on cannabis growers.

Social capital, opportunity, and school-based victimization.

This study extends the opportunity theory of victimization to consider the social capital of adolescents at school. We argue that social capital might act as a protective factor potentially encompassing both the concepts of guardianship and target attractiveness. Drawing on a sample of 5395 adolescents interviewed in the context of the 2007 National Crime Victimization Survey (school crime supplement), we develop school-specific measures of social capital and opportunity indicators in predicting violent and theft victimization on school grounds. The results show that opportunity indicators are strong predictors of both violent and theft victimization and that social capital is especially important as a protective factor from violent victimization. More specifically, the results indicate that students who developed trust relationships with adults at school benefit from these relationships by avoiding violent encounters with potential offenders. Implications for opportunity theories of victimization are discussed.

Drug dealing cessation among a cohort of drug users in Vancouver, Canada.

INTRODUCTION: Drug dealing among drug users has been associated with elevated risk-taking and negative health outcomes. However, little is known about the cessation of drug dealing among this population. METHODS: We assessed time to cessation of drug dealing using Cox regression. We also used generalized estimating equation (GEE) analysis and chi-square analysis to examine factors associated with willingness to cease drug dealing. RESULTS: In total, 868 participants reported drug dealing between November 2005 and March 2009. Among 381 participants dealing drugs at baseline, 194 (51%) ceased dealing. Incidence of dealing cessation was positively associated with spending less than $50 per day on drugs (Adjusted Hazard Ratio [AHR]=1.88, 95% confidence interval [CI]: 1.14-3.10) and negatively associated with buying drugs from the same source (AHR=0.60, 95% CI: 0.37-0.98). In a GEE analysis, willingness to cease dealing was positively associated with older age (Adjusted Odds Ratio [AOR]=1.02, 95% CI: 1.01-1.03), crack use (AOR=2.00, 95% CI: 1.44-2.79), public injecting (AOR=1.95, 95% CI: 1.55-2.43), and reporting that police presence affects drug purchases (AOR=1.53, 95% CI: 1.22-1.91), and negatively associated with crystal methamphetamine injection (AOR=0.62, 95% CI: 0.47-0.83). DISCUSSION: Intensity of drug use and acquisition method were predictive of dealing cessation. Willingness to cease dealing was associated with a range of risky drug-related activities. Interventions to reduce drug dealing should be conceived in tandem with addiction treatment strategies.

Beamforming for directional sources: additional estimator and evaluation of performance under different acoustic scenarios.

Beamforming is done with an array of sensors to achieve a directional or spatially-specific response by using a model of the arriving wavefront. Conventionally, a plane wave or point source model is used and this can cause decreased array gain or even total breakdown of beamforming when the source is directional. To avoid this, the authors proposed in recent work an alternative beamforming method which defines a set of "sub-beamformers," each designed to respond to a different spatial mode of the source. The outputs of the individual sub-beamformers are combined in a weighted sum to give an overall output of better quality than that of a monopole beamformer. This paper extends the previous work by introducing an additional estimator for the weighted sum and by presenting simulation results to demonstrate the relative performance of the proposed method and the different estimators for a directional source in the presence of diffuse noise, reverberation, and an interfering source. Gain optimization subject to a constraint on the white-noise gain with the proposed beamforming method is also introduced. Generally, when beamforming on directional sources, the proposed method outperforms beamforming with a point source model when the input signal-to-noise ratio (SNR) is 0 dB or higher.

The global diversion of pharmaceutical drugsnon-medical use and diversion of psychotropic prescription drugs in North America: a review of sourcing routes and control measures.

AIMS: North America features some of the world's highest consumption levels for controlled psychoactive prescription drugs (PPDs; e.g. prescription opioids, benzodiazepines, stimulants), with non-medical use and related harms (e.g. morbidity, mortality) rising in key populations in recent years. While the determinants, characteristics and impacts of these 'use' problems are increasingly well documented, little is known about the 'supply' side of non-medical PPD use, much of which is facilitated by 'diversion' as a key sourcing route. This paper provides a select review of the phenomenon of PPD diversion in North America, also considering interventions and policy implications. METHODS: A conceptual and empirical review of select-peer- and non-peer-reviewed research literature from 1991 to 2010 focusing upon PPD diversion in North America was conducted. RESULT: The phenomenon of PPD diversion is heterogeneous. Especially among general populations, a large proportion of PPDs for non-medical use are obtained from friends or family members. Other PPD diversion routes involve 'double doctoring' or 'prescription shopping'; street drug markets; drug thefts, prescription forgeries or fraud; as well as PPD purchases from the internet. CONCLUSIONS: The distinct nature and heterogeneity make PPD diversion a complex and difficult target for interventions. Prescription monitoring programs (PMPs) appear to reduce overall PPD use, yet their impact on reducing diversion or non-medical use is not clear. Law enforcement is unlikely to reach PPD diversion effectively. Effective reduction will probably require reductions in overall PPD consumption volumes, although such will need to be accomplished without compromising standards of good medical (e.g. pain) care.

Speech enhancement based on nonlinear models using particle filters.

Motivated by the reportedly strong performance of particle filters (PFs) for noise reduction on essentially linear speech production models, and the mounting evidence that the introduction of nonlinearities can lead to a refined speech model, this paper presents a study of PF solutions to the problem of speech enhancement in the context of nonlinear, neural-type speech models. Several variations of a global model are presented (single/multiple neurons; bias/no bias), and corresponding PF solutions are derived. Different importance functions are given when beneficial, Rao-Blackwellization is proposed when possible, and dual/nondual versions of each algorithms are presented. The method shown can handle both white and colored noise. Using a variety of speech and noise signals and different objective quality measures, the performance of these algorithms are evaluated against other PF solutions running on linear models, as well as some traditional enhancement algorithms. A certain hierarchy in performance is established between each algorithm in the paper. Depending on the experimental conditions, the best-performing algorithms are a classical Rao-Blackwellized particle filter (RBPF) running on a linear model, and a proposed PF employing a nondual, nonlinear model with multiple neurons and no biases. With consistence, the neural-network-based PF outperforms RBPF at low signal-to-noise ratio (SNR).

Convenient labour: the prevalence and nature of youth involvement in the cannabis cultivation industry.

BACKGROUND: The emergence of cannabis cultivation in industrialised countries may offer adolescents, especially those living in regions suitable for outdoor cultivation, new opportunities to participate in the drug trade. The current study examines the prevalence and the nature of youth involvement in cannabis cultivation in an important agricultural region of Quebec, Canada. METHODS: A self-report delinquency survey was administered to 1262 adolescents between 13 and 17 years who were attending one of four secondary schools in that region. The study location was not chosen arbitrarily. The region was known for having a larger than average outdoor cannabis industry, and various media reports suggested that a substantial number of students missed school days during the cannabis harvest season, in October. RESULTS: A first set of findings show that 12% of respondents reported having participated in the cannabis cultivation industry in the past year. Such a prevalence rate is higher than for any other type of crime found in the survey (except for the general category of mischief)--including assault and theft, and is comparable to the prevalence rates found for drug dealing. Such a high prevalence rate comes in part out of need for labour in this low population density region: 35% of respondents who reported having participated in the industry in the past year, were "labourers", while many others only participated in small sites, destined for personal use. Another set of findings suggest that growers are a very diverse group: although cultivation is the most prevalent money-generating crime for gang members in the region, girls and otherwise conventional adolescents are also involved in high numbers. CONCLUSION: These results emphasise the need to design policies that concern not just the prevention of drug use among youth, but also youth involvement in the supply of drugs. In addition, it underlines the difficulty of planning general interventions in what appears to be a very heterogeneous population of growers.

Beamforming with microphone arrays for directional sources.

Beamforming is done with an array of sensors to achieve a directional or spatially-specific response by using a model of the arriving wavefront. Real acoustic sources may deviate from the conventional plane wave or monopole model, causing decreased array gain or a total breakdown of beamforming. An alternative to beamforming with the conventional source model is presented which avoids this by using a more general source model. The proposed method defines a set of "sub-beamformers," each designed to respond to a different spatial mode of the source. The outputs of the individual sub-beamformers are combined in a weighted sum to give an overall output of better quality than that of a conventional (monopole) beamformer. It is shown that with appropriate weighting, the optimum array gain can be achieved. A simple method is demonstrated to estimate the weighted sum, based on the observed data. The variance and bias of the estimate in the presence of noise are evaluated. Simulation and experimentally measured results are shown for a simple directive source. In the experiment, the proposed method provides an array gain of about 11 dB while beamforming using a point source model achieves only -4 dB.