Management sampling for larvae of the colorado potato beetle

Summary Untreated plot of ‘Kennebec’ and ‘Superior’ potatoes were sampled for Colorado potato beetle (CPB) at L'Assomption, Quebec, in 1982, 1986 and 1987. Numbers of CPB larvae per stalk were counted on 74 occasions for sample sizes ranging from 50 to 200 stalks. Regression techniques were used to estimate the relationship between mean and cumulative proportion of stalks infected. These were used to set up binomial sequential probability ratio test (SPRT) sampling plans for pest management decision making with tally numbers (or tally thresholds, cutoff numbers) equal to 0,1,...10. A binomial scheme defined by tally number equal to 4 is proposed for general use, and corresponding plans are given, with estimated operating characteristic and average sample number curves.     

A model for the assessment of static and dynamic factors in sexual offenders

A sample of 519 sexual offenders who were consecutive admissions to the Ontario Region of Correctional Service of Canada (CSC) were assessed with reference to a large series of variables thought to be related to sexual offending. We grouped these variables into five domains: criminality, social competence, sexual deviance, substance abuse and treatment readiness. We standardized scores on each of these domains to facilitate the calculation of total scores for each domain. We then performed a variety of analyses to determine whether these domains might constitute a reasonable model for the comprehensive evaluation of sexual offenders. Analyses indicated that overall the model received a moderate level of support.     

Do Infants Recognize Engagement in Social Interactions? The Case of Face‐to‐Face Conversation

This study explores 12‐month‐olds' understanding of face‐to‐face conversation, a key contextual structure associated with engagement in a social interaction. Using a violation‐of‐expectations paradigm, we habituated infants to a “face‐to‐face” conversation, and in a test phase compared their looking times between “back‐to‐back” (conceptually novel) and “face‐to‐face” (conceptually familiar) conversations, while simultaneously manipulating perceptual familiarity in a 2 × 2 factorial design. We also analyzed dynamic changes in pupil dilation, which are considered a reliable measure of cognitive load that may index processing of social interactions. Infants looked relatively longer at perceptual changes (new speaker positions) but not at conceptual change (back‐to‐back conversation), suggesting that face‐to‐face conversation may not elicit particular expectations, and so may not carry any particular conceptual significance. Moreover, on the first test trial, larger pupil dilation was observed for familiar conditions, suggesting that familiarity with perceptual features could enhance processing of conversations. Thus, this study undermines assertions regarding infants' conceptual understanding of the social signals underlying engagement. Infants may rather recognize such signals through their perceptual familiarity and associated positive feelings. This may then increase their engagement when observing and participating in others' collaborative activities, in turn allowing for the development of knowledge regarding others' intentions.     

Density yield relationships and economic injury level model for the Colorado potato beetle larvae on potatoes

Summary A three year study revealed that the relationship between the density of Colorado potato beetle larvae per stalk and a decrease in the yield of potatoes can be described by a model comprised of two straight lines. Potato cv. Superior was found to have a damage boundary of 12 larvae per stalk, which is the maximum level of injury or pest density below which no noticeable yield loss occurs. The economic injury level was estimated as a function of larval density in relation to yield, cost of protection, efficacy of treatment, value of the crop and expected harvest in the absence of any loss.     

Firm outsourcing decisions: evidence from U.S. foreign trade zones

This article examines the operations of firms located in U.S. foreign trade subzones to study the responsiveness of outsourcing to international cost changes. I find that firms reduce their reliance on foreign inputs when dollar depreciation increases the relative price of imported inputs. The effect is pervasive across industries and is economically significant. In addition, firms that rely more heavily on imported intermediate inputs reduce their overall shipments when dollar depreciation elevates their imported, input costs. However, the magnitude of the shipments effect is economically small, suggesting that firms respond to exchange rate movements by adjusting their operations on other dimensions.