Optimal Treatment Schedule in Insect Pest Control in Viticulture

A model for the control of the European grapevine moth Lobesia botrana includes two control methods: insecticides and mating disruption. It yields the combination and schedule of application that minimize cost and losses due to the pest. A simulation is presented for an experimental situation.     

The impact of missing data on the results of a schizophrenia study

Missing data pose a serious challenge to the integrity of randomized clinical trials, especially of treatments for prolonged illnesses such as schizophrenia, in which long‐term impact assessment is of great importance, but the follow‐up rates are often no more than 50%. Sensitivity analysis using Bayesian modeling for missing data offers a systematic approach to assessing the sensitivity of the inferences made on the basis of observed data. This paper uses data from an 18‐month study of veterans with schizophrenia to demonstrate this approach. Data were obtained from a randomized clinical trial involving 369 patients diagnosed with schizophrenia that compared long‐acting injectable risperidone with a psychiatrist's choice of oral treatment. Bayesian analysis utilizing a pattern‐mixture modeling approach was used to validate the reported results by detecting bias due to non‐random patterns of missing data. The analysis was applied to several outcomes including standard measures of schizophrenia symptoms, quality of life, alcohol use, and global mental status. The original study results for several measures were confirmed against a wide range of patterns of non‐random missingness. Robustness of the conclusions was assessed using sensitivity parameters. The missing data in the trial did not likely threaten the validity of previously reported results. Copyright © 2014 John Wiley & Sons, Ltd.     

Heritage corridors: transnational flows and the built environment of migration

ABSTRACT

In settler nations such as Australia, which have high migrant intakes, a category of cultural heritage practice has emerged that focuses on the material record of immigration. Currently, a nation-bounded approach tends to be taken to the recording and interpretation of this heritage, an approach that largely ignores the transnational social fields to which the immigrants who created the heritage places and buildings belonged. I propose the concept ‘heritage corridor’ to aid in conceptualising the transnational connectivity between migrant heritage sites in Australia and overseas locales as well as the bi-directional flow of ideas and capital that is often materially evident in the built environments, both rural and urban, encompassed by such a corridor. Focusing on Chinese overseas migration in the nineteenth and twentieth centuries, I describe how transnational remittances were instrumental in the building of houses, temples, schools, shops, roads and bridges in Guangdong Province, many of which are now regarded as heritage items. As an example of how the field of heritage studies may productively dialogue with migration studies, new thinking on material agency is drawn upon to account for the way remittance-built houses become entangled in the lives and aspirations of those at opposite poles of a heritage corridor.     

Evaluating the Move to a Linear Tax System in Germany and Other European Countries

This paper proposes a comparison of the results of tax policy analysis obtained on the basis of unitary and collective representations of the household. We first generate labour supplies consistent with the collective rationality, by use of a model calibrated on microdata as described in Vermeulen et al. [Collective Models of Household Labor Supply with Nonconvex Budget Sets and Nonparticipation: A Calibration Approach (2006)]. A unitary model is then estimated on these collective data and unitary and collective responses to a tax reform are compared. We focus on the introduction of linear taxation in Germany. The exercise is replicated for other European countries and other topical reforms. Distortions due to the use of a unitary model turn out to be important in predicting labour supply adjustments, in the design of tax revenue neutral reforms, and in predicting a reform’s welfare implications.

Monotonicity of ‘ranking by choosing’: A progress report

Procedures designed to select alternatives on the basis of the results of pairwise contests between them have received much attention in literature. The particular case of tournaments has been studied in depth. More recently weak tournaments and valued generalizations thereof have been investigated.The purpose of this paper is to investigate to what extent these choice procedures may be meaningfully used to define ranking procedures via their repeated use, i.e. when the equivalence classes of the ranking are determined by successive applications of the choice procedure. This is what we call ranking by choosing. As could be expected, such ranking procedures raise monotonicity problems. We analyze these problems and show that it is nevertheless possible to isolate a large class of well-behaved choice procedures for which failures of monotonicity are not overly serious. The hope of finding really attractive ranking by choosing procedures is however shown to be limited. Our results are illustrated on the case of tournaments.I am grateful to Hervé Raynaud and Jean-Claude Vansnick for stimulating discussions. Jean-François Laslier, Thierry Marchant, Bernard Monjardet, Xavier Juret and an anonymous referee made very helpful comments on earlier drafts of this text. Special thanks go to Patrice Perny who introduced me to the subject and to Olivier Hudry for his help with Slater orders. The usual caveat applies. Part of this work was accomplished while I was visiting the Service de Mathématiques de la Gestion at the Université Libre de Bruxelles (Brussels, Belgium). I gratefully acknowledge the warm hospitality of the Service de Mathématique de la Gestion as well as the support from the Belgian Fonds National de la Recherche Scientifique and the Brussels-Capital Region through a Research in Brussels action grant.     

A Quantitative Risk Assessment of Waterborne Cryptosporidiosis in France Using Second-Order Monte Carlo Simulation

A pragmatic quantitative risk assessment (QRA) of the risks of waterborne Cryptosporidium parvum infection and cryptosporidiosis in immunocompetent and immunodeficient French populations is proposed. The model takes into account French specificities such as the French technique for oocyst enumeration performance and tap water consumption. The proportion of infective oocysts is based on literature review and expert knowledge. The probability of infection for a given number of ingested viable oocysts is modeled using the exponential dose-response model applied on published data from experimental infections in immunocompetent human volunteers challenged with the IOWA strain. Second-order Monte Carlo simulations are used to characterize the uncertainty and variability of the risk estimates. Daily risk of infection and illness for the immunocompetent and the immunodeficient populations are estimated according to the number of oocysts observed in a single storage reservoir water sample. As an example, the mean daily risk of infection in the immunocompetent population is estimated to be 1.08 x 10(-4) (95% confidence interval: [0.20 x 10(-4); 6.83 x 10(-4)]) when five oocysts are observed in a 100 L storage reservoir water sample. Annual risks of infection and disease are estimated from a set of oocyst enumeration results from distributed water samples, assuming a negative binomial distribution of day-to-day contamination variation. The model and various assumptions used in the model are fully explained and discussed. While caveats of this model are well recognized, this pragmatic QRA could represent a useful tool for the French Food Safety Agency (AFSSA) to define recommendations in case of water resource contamination by C. parvum whose infectivity is comparable to the IOWA strain.     

Labour Participation of Higher Education Students

The aim of this article is to shed light on the determinants of the decision to participate in the labour force while studying, and of the intensity of this participation as measured by the wages earned by students. We show that students react to their future expected economic benefits associated with their chosen course of study. In this sense, our results confirm Lévy‐Garboua’s (Revue française de Sociologie XVII: 53–80, 1976) thesis of working as an adjustment variable for the variations in the expected rate of return of discipline. Our results indicate that the decision to work while studying and its intensity depend on students’ socioeconomic status and material needs, as well as external financial resources. Altogether, our results suggest that the equity and internal efficiency implications of such a social bias in the labour force participation behaviour might not be too important, but that some public interventions might nevertheless improve the overall external efficiency by allowing students to spend more time on more valorizing activities rather than unskilled and low‐paid jobs.     

Getting into the Groove: The Development of Tempo‐Flexibility Between 10 and 18 Months of Age

Despite good early rhythm processing abilities, and clear enjoyment of music, infants appear not to be able to spontaneously synchronize their movement to the beat of a song (Zentner and Eerola, Proceedings of the National Academy of Sciences, 107, 2010, 5768). We present a new social bell‐ringing task designed to facilitate synchronous movement to music in infants. Ten‐month‐olds, 18‐month‐olds, and adults were played musical tracks of various tempos and given handheld bells to ring, in the presence of either a live experimenter or an animated nonsocial stimulus. Surface electromyography (EMG) was used to measure the timing of arm movements during periods of bell ringing. Infants showed no evidence of synchronous bell ringing at any tempo. However, while the 10‐month‐olds did not modulate their ringing to the music tempo, the 18‐month‐olds showed tempo‐flexibility. Moreover, 18‐month‐olds displayed more associated behaviors such as bouncing and rocking in the absence (rather than presence) of a social partner, whereas the behavior of the 10‐month‐olds was not modulated by the presence or absence of a social partner. The results suggest a distinction between “moving together” and “moving to the beat,” which may have separate underlying mechanisms and developmental trajectories.     

Do husbands and wives pool their incomes? A couple experiment

We propose a simple and direct test of in-couple income pooling and provide a typology of couples that pool resources and those who do not. For this purpose, we performed a five-round experiment with 95 established real-life couples in Germany. In each round, the couples received the same total amount of money, but the relative allocation to the spouses differed and they had to agree on an irreversible private goods consumption pattern. We find that for the majority of the sample, the consumption choices depend on the spouses’ relative resources. While this suggests a rejection of income pooling at the mean, a substantial share of the couples do indeed pool their resources. Pooling behavior is more common among couples in which the spouses’ socioeconomic characteristics are more similar. In particular, traditional couples with distinct work division between the spouses are significantly less likely to pool their individual resources and treat any spouse’s income symmetrically. Conventional variables used to approximate income pooling are only loosely related to the behavior observed in our experiment.     

Does a firm’s exposure to ethical failures matter to financial markets? A governance perspective

This paper investigates if a firm’s ethical reputation, in conjunction with its governance, affects its standing within financial markets. A firm`s ethical reputation, as measured by ethical failures, arises from its involvement in ethical violations and incidents while a comprehensive index proxies for governance. We assess a firm’s standing within financial markets through two complementary perspectives, i.e., the level of information asymmetry between managers and investors, as inferred from analyst forecast dispersion and analyst forecast error, and the relation between a firm’s earnings and its stock market valuation or return (value relevance). Our results suggest that a firm`s ethical reputation affects financial analysts’ forecasts as well as the stock market value assigned to its reported earnings. Moreover, it appears that corporate governance moderates such relations, with strong (weak) governance compensating for a weak (strong) ethical reputation. Overall, our evidence shows that ethical failures do not seem to pay.