Latin hypercube sampling with multidimensional uniformity

Complex models can only be realized a limited number of times due to large computational requirements. Methods exist for generating input parameters for model realizations including Monte Carlo simulation (MCS) and Latin hypercube sampling (LHS). Recent algorithms such as maximinLHS seek to maximize the minimum distance between model inputs in the multivariate space. A novel extension of Latin hypercube sampling (LHSMDU) for multivariate models is developed here that increases the multidimensional uniformity of the input parameters through sequential realization elimination. Correlations are considered in the LHSMDU sampling matrix using a Cholesky decomposition of the correlation matrix. Computer code implementing the proposed algorithm supplements this article. A simulation study comparing MCS, LHS, maximinLHS and LHSMDU demonstrates that increased multidimensional uniformity can significantly improve realization efficiency and that LHSMDU is effective for large multivariate problems.     

Adolescent Personality as Risk and Resiliency in the Testosterone–Externalizing Association

Previous investigations of testosterone and externalizing behavior have provided mixed findings. We tested the hypothesis that self‐regulatory personality moderates the testosterone–externalizing behavior association in adolescence. Parents reported on their 13‐ to 18‐year‐old (N = 106, M_age = 16.01, SD = 1.29) children's personalities and psychopathology. Testosterone was measured via drool samples. As hypothesized, personality moderated the testosterone–externalizing behavior association. High testosterone predicted higher levels of externalizing behaviors, but only for adolescents low in Agreeableness and Conscientiousness. Also, personality acted as a resiliency factor: high levels of Conscientiousness, in the presence of high testosterone, predicted lower levels of rule breaking. Results highlight how endogenous factors, such as personality, may interact with testosterone, and emphasize the relevance of including personality moderators in future research.     

Sport and disability: Pistorius does not fit with the categories

Oscar Pistorius presents a major issue to sports organisations, as exposed in the media. First and foremost, media wrongly perceive him as the first disabled athlete to participate in the Olympic Games. Second, they openly question the legitimacy of his participation mainly based on the inequity introduced by his prosthetic legs. Content analysis, in English and French, of written press, International Association of Athletics Federations (IAAF) and Court of Arbitration for Sport (CAS) texts, from 2004 to 2012, confirms that Pistorius presents a new puzzle to sports organizations. This is partly because they are not able to determine whether his performances are a result of his body strength or if they are biased by his artificial limbs. Furthermore, when he is competing against able-bodied athletes, sports organizsations put him in a ‘monstrous’ position. Similarly, while categorising him as an ‘athlete’ they do not grant him the characteristic feature of this category: certified comparability of performances to ultimately establish ranks.     

Reduction in Dietary Acrylamide Exposure—Impact of Potatoes with Low Acrylamide Potential

Acrylamide forms primarily from a reaction between reducing sugars (e.g., glucose and fructose) and an amino acid (asparagine, Asn) formed naturally in foods, including potatoes. This reaction occurs when carbohydrate‐rich foods are heated at temperatures above 120 °C. Multiple potato varieties were transformed with potato genomic DNA that results in down‐regulation of the expression of the asparagine synthetase‐1 gene (Asn1), significantly reducing synthesis of free Asn, and consequently lowering the potential to form acrylamide during cooking. These potatoes with low acrylamide potential (LAP) were tested in agronomic trials, and processed into French fries and potato chips. Decreased levels of acrylamide were measured in these cooked food products when derived from LAP potatoes compared with those derived from conventional potatoes. These reductions can be directly attributed to reduction in Asn levels in the LAP potatoes. The corresponding average reduction in exposure to acrylamide from French fry and potato chip consumption is estimated to be 65%, which would amount to approximately a 25% reduction in overall dietary exposure. Considering that children consume nearly three times more acrylamide than adults on a per kg body weight basis, they would experience the most impact from the reduced acrylamide associated with LAP potatoes. The potential public health impacts, in context of dietary acrylamide exposure reduction, are discussed in this study.     

Attachment and Self‐Efficacy in Career Search Activities: A Structural Model

The author integrated attachment theory with social cognitive career theory (SCCT) to examine how attachment styles influence the career search self‐efficacy activities of interviewing, networking, job searching, and personal exploration. Using an undergraduate sample (N = 275, 81% women), the author tested a structural model. Results indicated that anxious attachment style was negatively related to interviewing self‐efficacy, whereas avoidant attachment style was negatively related to networking, job searching, and personal exploration self‐efficacy. Theoretical implications based on these findings provide support for an integrative model of attachment theory with SCCT. Career counselors are encouraged to consider clients’ attachment styles when working with individuals who are searching for employment. To help address the limitations of the study, future researchers could test the applicability of the current model with a more diverse sample.     

Recollections of Jack Michael and the Application of Skinner’s Analysis of Verbal Behavior

The Analysis of Verbal Behavior - Jack Michael offered a course on verbal behavior almost every year throughout his teaching career. Jack was also interested in the application of Skinner's...     

The Slaughtered and the Survivors: Collaboration Between Social Economy Organizations as a Key to Success in Times of Financial Crisis

The objective of this study is to analyze the aspects that allowed a critical part of Social Economy Organizations (SEOs) to survive a recession period, especially participation in collaborative networks. The financial stress of an SEO will depend on the resources and capabilities available to the organization. To analyze the financial stress of Spanish SEOs, we defined a sample of 714 SEOs. Approximately half of these organizations suffered from financial stress in the analyzed period (2009–2012). The results obtained in this study reveal the existence of three factors that distinguish organizations under financial stress: (a) a high dependence on government funding; (b) changes in the relationship between staff and volunteers; and (c) a lack of access to markets. The combination of these three elements results in an unsustainable situation for the organization. The development of a collaborative profile increases the SEO’s probability of surviving the adverse manifestations of its environment.     

A Diversity Index for Model Space Selection in the Estimation of Benchmark and Infectious Doses via Model Averaging

In chemical and microbial risk assessments, risk assessors fit dose‐response models to high‐dose data and extrapolate downward to risk levels in the range of 1–10%. Although multiple dose‐response models may be able to fit the data adequately in the experimental range, the estimated effective dose (ED) corresponding to an extremely small risk can be substantially different from model to model. In this respect, model averaging (MA) provides more robustness than a single dose‐response model in the point and interval estimation of an ED. In MA, accounting for both data uncertainty and model uncertainty is crucial, but addressing model uncertainty is not achieved simply by increasing the number of models in a model space. A plausible set of models for MA can be characterized by goodness of fit and diversity surrounding the truth. We propose a diversity index (DI) to balance between these two characteristics in model space selection. It addresses a collective property of a model space rather than individual performance of each model. Tuning parameters in the DI control the size of the model space for MA.     

Ecosystem services provided by urban spontaneous vegetation

Spontaneous vegetation colonizes large areas in and around cities. These unmanaged areas are considered to have low economic value or indicate dereliction, but recent research suggests that these can contribute valuable ecosystem services. This study evaluates indicators of ecosystem services in three habitats: urban spontaneous vegetation (USV), managed lawns, and semi-natural urban forest, in Halifax, Nova Scotia. USV had higher indicator values for habitat provisioning (plant species diversity, invertebrate abundance and taxonomic diversity) than the other habitats. Indicators of climatic regulatory services (albedo and leaf area index) in USV were similar to those in lawn habitats. Organic carbon content of the soils, an indicator of carbon storage, was lowest in USV but only marginally lower than in lawns. Standing biomass, an indicator of production services, was lowest in USV but lawn production may have been overestimated. While USV sites are usually transitory components of the urban landscape, they deserve further consideration due to their provision of ecosystem services, in some cases to a greater extent than conventionally valued urban habitats.