127 research outputs found

    Just Noticeable Differences for Vehicle Rates of Closure

    Get PDF
    The goal for this research was to identify the just noticeable difference (JND) for vehicle rates of closure. In our attempt to identify the JND we used two traditional psychophysical methods. However, these procedures resulted aberrant relationships between rate of closure and percent correct. Both of the traditional procedures used a sequential presentation of a standard animation and a comparison animation. The final method used a change in the rate of closure within the animation. This method provided us with a JND of between 12.9 to 16.1 km/h (8 to 10 mph). Reasons for the aberrant findings using the traditional methods are discussed

    Crop Responses to AmiSorb in the North Central Region

    Get PDF
    Originally used to prevent scale in boilers, carpramid or thermal polyaspartate (copoly[(3-carboxypropionamide)( 2-carboxylmethyl) acetamide)] was brought to agriculture under the trade names AmiSorb and Magnet. It claimed to increase nutrient uptake through artificially increasing the volume of soil occupied by roots through increased root branching and root hair development. Under controlled hydroponic or greenhouse conditions, the use of carpramid increased nutrient uptake, some yield determining factors such as wheat tillering and in some cases, crop yield. Extensive field testing from 1996 to 1998 under various nutrient regimes, placements, forms, and timings resulted in very inconsistent performance. Averaged across all experiments for which data were available, small yield increases were observed for corn (+1.75 bushels/acre), soybean (+0.63 bushel/acre), wheat (+1.07 bushels/acre), and grain sorghum (+0.32 bushel/acre), but at best only about one-fourth of the experiments (27 percent for corn and wheat) showed statistically significant yield increases. Across all crops, only three experiments showed an economic advantage to using carpramid. An attempt was made to better define the conditions when responses were observed but no clear pattern emerged that would allow improved probability of predicting a positive response.https://lib.dr.iastate.edu/extension_pubs/1225/thumbnail.jp

    The effects of problem-oriented policing on crime and disorder

    Get PDF
    Problem-oriented Policing (POP) was first introduced by Herman Goldstein in 1979. The approach was one of a series of responses to a crisis in effectiveness and legitimacy in policing that emerged in the 1970s and 1980s. Goldstein argued that police were not being effective in preventing and controlling crime because they had become too focused on the “means” of policing and had neglected the “goals” of preventing and controlling crime and other community problems. Goldstein argued that the unit of analysis in policing must become the “problem” rather than calls or crime incidents as was the case during that period. POP has had tremendous impact on American policing, and is now one of the most widely implemented policing strategies in the US. To synthesize the extant problem-oriented policing evaluation literature and assess the effects of problem-oriented policing on crime and disorder Eligible studies had to meet three criteria: (1) the SARA model was used for a problemoriented policing intervention; (2) a comparison group was included; (3) at least one crime or disorder outcome was reported with sufficient data to generate an effect size. The unit of analysis could be people or places. Several strategies were used to perform an exhaustive search for literature fitting the eligibility criteria. First, a keyword search was performed on an array of online abstract databases. Second, we reviewed the bibliographies of past reviews of problem-oriented policing. Third, we performed forward searches for works that have cited seminal problem-oriented policing studies. Fourth, we performed hand searches of leading journals in the field. Fifth, we searched the publications of several research and professional agencies. Sixth, after finishing the above searches we e-mailed the list of studies meeting our eligibility criteria to leading policing scholars knowledgeable in the area of problem-oriented policing to ensure we had not missed any relevant studies. For our ten eligible studies, we provide both a narrative review of effectiveness and a meta-analysis. For the meta-analysis, we coded all primary outcomes of the eligible studies and we report the mean effect size (for studies with more than one primary outcome, we averaged effects to create a mean), the largest effect, and the smallest effect. Because of the heterogeneity of our studies, we used a random effects model. Based on our meta-analysis, overall problem-oriented policing has a modest but statistically significant impact on reducing crime and disorder. Our results are consistent when examining both experimental and quasi-experimental studies. Conclusions: We conclude that problem-oriented policing is effective in reducing crime and disorder, although the effect is fairly modest. We urge caution in interpreting these results because of the small number of methodologically rigorous studies on POP and the diversity of problems and responses used in our eligible studies

    Why Did People Stop Committing Crimes? An Essay About Criminology And Ideology

    Get PDF
    This essay considers the sharp decline in crime that was observed in 1994 in New York City and across the nation. The author suggests that crime reduction in various areas must be understood in a local context. This article discusses the steps New York City took prior to the observed crime reduction. The essay then discusses how urban renewal projects, weakening institutional control of youth behavior, and highly centralized facilities and strategies of law enforcement may have contributed to the violence of the 1980\u27s. The author concludes that bad social policies contributed to elevated the crime rate and improvement of those policies helped reduce the crime rate
    • …
    corecore