Effectiveness of FISK,an Invasiveness Screening Tool for Non‐Native Freshwater Fishes,to Perform Risk Identification Assessments in the Iberian Peninsula

Risk assessments are crucial for identifying and mitigating impacts from biological invasions. The Fish Invasiveness Scoring Kit (FISK) is a risk identification (screening) tool for freshwater fishes consisting of two subject areas: biogeography/history and biology/ecology. According to the outcomes, species can be classified under particular risk categories. The aim of this study was to apply FISK to the Iberian Peninsula, a Mediterranean climate region highly important for freshwater fish conservation due to a high level of endemism. In total, 89 fish species were assessed by three independent assessors. Results from receiver operating characteristic analysis showed that FISK can discriminate reliably between noninvasive and invasive fishes for Iberia, with a threshold of 20.25, similar to those obtained in several regions around the world. Based on mean scores, no species was categorized as “low risk,” 50 species as “medium risk,” 17 as “moderately high risk,” 11 as “high risk,” and 11 as “very high risk.” The highest scoring species was goldfish Carassius auratus. Mean certainty in response was above the category “mostly certain,” ranging from tinfoil barb Barbonymus schwanenfeldii with the lowest certainty to eastern mosquitofish Gambusia holbrooki with the highest level. Pair‐wise comparison showed significant differences between one assessor and the other two on mean certainty, with these two assessors showing a high coincidence rate for the species categorization. Overall, the results suggest that FISK is a useful and viable tool for assessing risks posed by non‐native fish in the Iberian Peninsula and contributes to a “watch list” in this region.     

Materials receiving capacity and inventory management

This paper analyses the optimal level of materials receiving capacity for a manufacturer that receives deliveries from many suppliers. Inventory levels and inventory carrying costs depend on the frequency of deliveries and thus, on the materials receiving capacity. An analytic model that captures the tradeoff between inventory costs and materials receiving costs is presented and discussed. The receiving cost is modeled as increasing in discrete jumps of varying sizes whenever materials receiving resources are added. Practical issues in implementing the model are highlighted and methods to reduce the marginal materials receiving cost are discussed. The paper also discusses connections to the JIT approach for production environments where materials receiving is heavily automated.     

An examination of the mechanisms underlying the effects of physical activity on brain and cognition

Physical activity positively influences brain health and cognitive functioning in older adults. Several physiological and psychological mechanisms have been identified to underlie such a relationship. Cardiovascular fitness is accompanied with changes in mechanisms such as cerebral blood flow, neurotrophic factors, neurotransmitter systems and neural architecture that have themselves been associated with cognitive performance. Factors associated with exercise such as arousal, mood and self-perception of competence seem also to influence cognitive performance. Other explanation for the benefits of exercise in cognition, results from the fact that the performance of motor skills involve an important cognitive component (e.g., executive functions and information processing speed). Evidence of brain plasticity and behavior has been provided from studies where animals are exposed to enriched or complex environments. Exposure to such paradigms in which physical activity plays an important role has been found to influence various aspects of brain function and structure. Studies using neuroimaging techniques have established a link between the acquisition of different motor skills and the occurrence of neuroplasticity in human adults. This literature review indicates that the type of exercise and its specific perceptual and cognitive characteristics may influence cognitive performance. However, most of the research has been focused on self-paced movements or automatized skills and few intervention studies have examined the results of merging exercise and cognitive training in a single program. An important scientific challenge for the coming years is to design exercise programs capable of mobilizing several type of mechanisms underlying the effects of physical activity on brain and cognition.     

The determinants of export performance: A review of the research in the literature between 1998 and 2005

Considerable attention has been paid to the determinants of export performance. However, despite this research effort in identifying and examining the influence of such determinants, the literature is characterized by fragmentation and diversity, hindering theory development and practical advancement in the field. This paper attempts to review and synthesize the knowledge on the subject. As a result, this study reviews and evaluates 52 articles published between 1998 and 2005 to assess the determinants of export performance. The assessment reveals that: (a) more studies have been conducted outside the USA; (b) the majority of the studies focus on manufacturing firms, with relatively few studies examining the service sector; (c) the majority of the export studies continue to focus on small to medium‐sized firms; (d) there is a continuous increase in the sample size; (e) despite the problems that may arise from the use of single informants, it seems that none of the studies reviewed here collected data from more than one informant in the firm; (f) an increasing number of studies have been using the export venture as the unit of analysis; (g) the level of statistical sophistication has improved; (h) the use of control and moderating variables in export performance studies has increased; (i) more studies have started to include the external environment in their models, including domestic market characteristics; and (j) market orientation as a key determinant of export performance emerges in this review. Finally, conclusions are drawn, along with some suggestions for further research.     

Populist things. A study on the materiality of political ideas

Is there such thing as a populist thing? This article tries to answer this question by comparing two iconic populist objects: the Make America Great Again (MAGA) cap and the yellow vest. Despite their centrality to populist politics, there is remarkably little systematic examination of these objects' populist affordances, let alone a comparative study. We propose to address this lacuna by performing a pragmatic analysis of each object's role in the populist politics of the United States and France, respectively. Our comparison uncovers two findings, which, in turn, help us answer our research question. First, our study of the MAGA cap reveals how nationalism and populism can be combined into a powerful political message. Second, the yellow vest exemplifies how populism functions on its own that is, as a way of doing politics that is centred on feelings of resentment. Either in conjunction with other political phenomena (e.g., nationalism) or by itself, populism emerges from our analysis as a logic of action that involves both linguistic claims and physical objects. Things, in this reading, are surprisingly central to how populism operates.     

Bayesian estimation for percolation models of disease spread in plant populations

Statistical methods are formulated for fitting and testing percolation-based, spatio-temporal models that are generally applicable to biological or physical processes that evolve in spatially distributed populations. The approach is developed and illustrated in the context of the spread of Rhizoctonia solani, a fungal pathogen, in radish but is readily generalized to other scenarios. The particular model considered represents processes of primary and secondary infection between nearest-neighbour hosts in a lattice, and time-varying susceptibility of the hosts. Bayesian methods for fitting the model to observations of disease spread through space and time in replicate populations are developed. These use Markov chain Monte Carlo methods to overcome the problems associated with partial observation of the process. We also consider how model testing can be achieved by embedding classical methods within the Bayesian analysis. In particular we show how a residual process, with known sampling distribution, can be defined. Model fit is then examined by generating samples from the posterior distribution of the residual process, to which a classical test for consistency with the known distribution is applied, enabling the posterior distribution of the P-value of the test used to be estimated. For the Rhizoctonia-radish system the methods confirm the findings of earlier non-spatial analyses regarding the dynamics of disease transmission and yield new evidence of environmental heterogeneity in the replicate experiments.     

The potential role of physical activity on driving performance and safety among older adults

The elderly represent the fastest growing driving population. Older drivers have a high crash rate per distance traveled, a high risk of injury or death in traffic accidents, and are commonly found to be ‘at fault’ in crashes. This reality has focused more interest on issues associated with the fitness to drive and the safety of older drivers. Many older adults depend greatly on their personal vehicle for transportation and suffer a marked loss of quality of life when, as a consequence of no longer being able or permitted to drive, their mobility becomes significantly restricted. The reasons for the deterioration of driving performance that occur during the aging process are multi-factorial and a great deal of research has focused on the identification of those factors. Nevertheless, some studies incorporating training programs have tried, with some success, to improve the driving-related abilities of older drivers. It has been demonstrated that physical activity can promote several skills that are associated with driving performance in older drivers. Few studies, though, have conducted exercise interventions among older drivers intended to enhance their driving-related abilities and promote road safety. In this context, the purpose of this work consists of examining the perceptual, cognitive, health, and physical factors related to fitness to drive in older adults and identifying possible strategies that can enhance their driving-related abilities. Moreover, potential mechanisms underlying the relationship among physical activity, driving ability, and road safety are discussed.     

Work Hours and Well Being: An Investigation of Moderator Effects

The relationship between work hours and subjective well being is marked by contradictory findings, thereby implying that it is far from being completely understood. A study of moderator effects can help explain variations in results across studies and, thus, overcome inconsistencies in past research. Accordingly, the current study aims to enlighten the relationship between work hours and well being by investigating how a number of variables moderate this relationship. To develop the research hypotheses concerning the moderator effects, this study relies mostly on social identity theory. Overall, the results suggest that work hours, per se, do not have a significant relationship with individual well being. Rather, their effects seem to depend on a number of issues, namely concerned with individuals’ objective characteristics, as well as their social identities.     

Near-exact distributions for the sphericity likelihood ratio test statistic

In this paper three near-exact distributions are developed for the sphericity test statistic. The exact probability density function of this statistic is usually represented through the use of the Meijer G function, which renders the computation of quantiles impossible even for a moderately large number of variables. The main purpose of this paper is to obtain near-exact distributions that lie closer to the exact distribution than the asymptotic distributions while, at the same time, correspond to density and cumulative distribution functions practical to use, allowing for an easy determination of quantiles. In addition to this, two asymptotic distributions that lie closer to the exact distribution than the existing ones were developed. Two measures are considered to evaluate the proximity between the exact and the asymptotic and near-exact distributions developed. As a reference we use the saddlepoint approximations developed by Butler et al. [1993. Saddlepoint approximations for tests of block independence, sphericity and equal variances and covariances. J. Roy. Statist. Soc., Ser. B 55, 171–183] as well as the asymptotic distribution proposed by Box.