Assessing the Validity of the Law of Crime Concentration Across Different Temporal Scales

Objectives

The present study examined if Weisburd’s (Criminology 53(2):133–157, 2015) law of crime concentration held across different theoretically relevant temporal scales.

Methods

The cumulative percentages of Philadelphia, PA USA street blocks and intersections experiencing 25 and 50 % of street robberies by hour of the day, days of the week, and seasons of the year were compared to the bandwidth percentages established by Weisburd (2015). Different analyses were used to determine the stability of the micro-places’ street robbery levels within the three temporal scales.

Results

We found that the cumulative percentages of street blocks and intersections experiencing 25 and 50 % of street robberies at each of the three temporal scales closely matched the bandwidth percentages expected from Weisburd (2015) and some micro-places experienced street robberies across all temporal periods while others had more isolated temporal concentrations.

Conclusion

Weisburd’s (2015) law of crime concentration holds across different theoretically relevant temporal scales, and future criminology of place studies should not ignore temporal crime patterns. Further, it may be possible to refine hot spots policing approaches by incorporating spatial–temporal crime concentrations.

     

¿Qué es racismo?: awareness of racism and discrimination in Ecuador

In the national consciousness, Ecuador is a mestizo nation. However, it is also an ethnically diverse nation with sizable minorities of indigenous and Afrodescended peoples. In national surveys, there is also a considerable minority who self-identify as blanco (white). Although there is strong evidence of continuing discrimination and prejudice toward both indigenous and Afro-descended peoples, there is little public discussion or political action addressing such issues. The emergence of a powerful and resilient indigenous movement in the late 1980s gained international interest and acclaim in the 1990s, in part because of the peaceful mobilization efforts and effective bargaining tactics of the movement. However, indigenous leaders usually have not engaged in a discourse of racismo and/or discriminación. There has been much less social movement solidarity and activism among Afro-Ecuadorians, but their leaders commonly employ a discourse of racismo and discriminación. In August and September 2004, a survey of more than eight thousand adult Ecuadorians was conducted in regard to racism and related topics. In this research, we use several measures from this survey that focus on awareness of and sensitivity to issues of racism, prejudice, and discrimination. Self-identification of respondents enables us to contrast the responses of whites, mestizos, Indians, and Afro-Ecuadorians to the measures. Other independent variables of interest are level of education, the region in which the respondent resides, and whether the respondent lives in an urban or rural area. Regression results show differences among the ethnic groups in levels of awareness of racism, but more powerful predictors are level of education and rural residence.     

Harm-reduction activism: a case study of an unsanctioned user-run safe injection site

Due to the ongoing health crisis among injection drug users in Vancouver, Canada, there have been repeated calls for the establishment of safe injection sites (SISs) since the early 1990s. In April 2003, in response to a large-scale police crackdown and government inaction, a group of activists opened an unsanctioned SIS in Vancouver's Downtown Eastside (DTES). The 327 Carrall Street SIS operated for 181 days despite considerable police harassment and limited financial support. During the operation of the SIS, volunteers supervised over 3000 injections and demonstrated the feasibility of a user-run low-threshold SIS. The experience of the SIS provides valuable lessons for those seeking to advance the interests of injection drug users through community mobilization and direct action approaches. In this article, Thomas Kerr, Megan Oleson, and Evan Wood describe the events surrounding the establishment, operation, and closing of the unsanctioned SIS, and outline the lessons learned.     

Quantification and aging of the post-blast residue of TNT landmines

Post-blast residues are potential interferents to chemical detection of landmines. To assess the potential problem related to 2,4,6-trinitrotoluene (TNT), its post-blast residue was identified and quantified. In the first part of this study laboratory-scale samples of TNT (2 g) were detonated in a small-scale explosivity device (SSED) to evaluate the explosive power and collect post-blast residue for chemical analysis. Initiator size was large relative to the TNT charge; thus, issues arose regarding choice of initiator, residue from the initiator, and afterburning of TNT. The second part of this study detonated 75 to 150 g of military-grade TNT (typical of antipersonnel mines) in 55-gal barrels containing various witness materials (metal plates, sand, barrel walls, the atmosphere). The witness materials were analyzed for explosive residue. In a third set of tests, 75-g samples of TNT were detonated over soil (from Fort Leonard Wood or Sandia National Laboratory) in an indoor firing chamber (100 by 4.6 by 2.7 m high). Targeted in these studies were TNT and four explosive-related compounds (ERC): 2,4-dinitrotoluene (DNT), 1,3-dinitrobenzene (DNB), 2- and 4-aminodinitrotoluene (2-ADNT and 4-ADNT). The latter two are microbial degradation products of TNT. Post-blast residue was allowed to age in the soils as a function of moisture contents (5 and 10%) in order to quantify the rate of degradation of the principal residues (TNT, DNT, and DNB) and formation of the TNT microbial degradation products (2-ADNT and 4-ADNT). The major distinction between landmine leakage and post-blast residue was not the identity of the species but relative ratios of amounts. In landmine leakage the DNT/TNT ratio was usually greater than 1. In post-blast residue it was on the order of 1 to 1/100th of a percent, and the total amount of pre-blast residue (landmine leakage) was a factor of 1/100 to 1/1000 less than post-blast. In addition, landmine leakage resulted in low DNT/ADNT ratios, usually less than 1, whereas pre-blast residues started with ratios above 20. Because with time DNT decreased and ADNT increased, over a month the ratio decreased by a factor of 2. The rate of TNT degradation in soil observed in this study was much slower than that reported when initial concentrations of TNT were lower. Degradation rates yielded half-lives of 40 and 100 days for 2,4-DNT and TNT, respectively.