Testing the equality among distribution functions from independent and right censored samples via Cramér–von Mises criterion

The traditional Cramér–von Mises criterion is used in order to develop a test to compare the equality of the underlying lifetime distributions in the presence of independent censoring times. Its asymptotic distribution is proved and a resampling plan, which is valid for unbalanced data situations, is proposed. Its statistical power is studied and compared with commonly used linear rank tests by Monte Carlo simulations and a real data analysis is also considered. It is observed that the new test is clearly more powerful than the traditional ones when there exists no uniform dominance among involved distributions and in the presence of late differences. Its statistical power is also good in the other considered scenarios.     

Aggregating Political Dimensions: Of the Feasibility of Political Indicators

Political indicators are widely used in academic writing and decision making, but remain controversial. This paper discusses the problems related to the aggregation functions they use. Almost always, political indicators are aggregated by weighted averages or summations. The use of such functions is based on untenable assumptions (existence of homogeneous substitution rates, total compensation, and strict monotonicity). We show through concrete examples how these hidden assumptions are likely to produce results that are basically an artifact of ad hoc decisions, which additionally contradict very fundamental notions common to all credible political theories. We suggest, also through example, that some—necessarily partial—solutions are possible.     

The Effect of Firm and Host Country Characteristics on the Choice of Entry Mode: Empirical Evidence from Spanish Firms

When investing abroad firms must choose betweengoing alone or with a partner – the so-calledownership structure decision. Additionally,firms can enter a new country by acquisitionsor by greenfield investments – the foreignestablishment mode decision. These twodecisions have traditionally been analyzedseparately in the literature on entry mode.What is more, this literature has much lessanalyzed hybrid entry modes, like partialacquisitions. The aim of this paper is toanalyze how the different factors analyzed inprior research influence the choice of entrymode when jointly taking into account fouralternative entry modes: greenfield whollyowned subsidiaries, greenfield joint ventures,full acquisitions and partial acquisitions. Theempirical analysis was carried out byestimating a multinomial logit model over asample of FDIs made by Spanish firms. Ourresults also contribute to the knowledge ofspecific patterns in the choice of entry modeby firms from late investor countries, likeSpain.     

An Empirical Analysis of Monitoring Behaviour and Private Benefits of Investors in the Spanish Market

The objective of our study is to look for anequilibrium among three factors: the privatebenefits that main shareholders can obtain fromthe firm, the social benefits derived from acertain ownership structure (such assupervision and alignment of interests) and thecosts derived from ownership concentration(such as loss of liquidity and riskdiversification). Our empirical analysis allowsus to conclude that the supervisory role ofownership is more intense in firms where thepotential conflict of interest betweenshareholders and managers is greater, andtherefore the value of the firm can beincreased through a specific composition of itsshareholders.     

A new approach in vocational rehabilitation in Iceland: preliminary report

The lack of vocational rehabilitation in Iceland inspired the Janus Rehabilitation initiative in the year 2000. The team currently consists of two occupational therapists, a social worker, a physiotherapist, a psychologist, and a physician. Janus uses resources from local education establishments and is located at the Reykjavík Technical School. A client-centred approach is used, enabling a flexible rehabilitation timeframe. The aim is to help the client back to employment/education. Advantage is taken of the facilities of the school where integration between education and rehabilitation takes place. Forty individuals have been admitted, with a mean time from work of 2.9 years, (range: 0-11 years). Seventeen (43%) have returned to employment/education. Twenty-three of those entering the programme are still on invalidity pension. The Canadian Occupational Performance Measurement (COPM) shows improvement in occupational performance and satisfaction. The Icelandic Quality of Life measurement also shows improvement. The results have been promising. However, a larger group is needed in order to draw clear unequivocal conclusions.     

The relationship between fishermen's health and sleeping habits

This article describes research on fishermen's health and sleeping habits in Iceland. It presents the first findings of the project that were presented in October 2002 at a conference that was organized during Seamen Safety Week in Iceland. It covers physical and mental stress symptoms, sleep disturbance, and obesity, as well as fishermen's own reaction to their health and well-being. Take notice that the findings that are presented in this article can be found in a report presented in August, when the whole study will be finished. Finally, it is concluded how successful the response has been and how the project can be used positively with other studies. It is also noted that, in fact, these findings will be used for further studies linked to safety on board.     

New african American life tables from 1935–1940 to 1985–1990*

New life tables for African Americans are presented from 1935 through 1990. They are based on a historical series of vital statistics data on deaths that have been corrected for age misreporting, on reconstructed population counts that have been adjusted for census underenumeration, and on births that have been corrected for underregistration. The new life tables show rapid mortality declines for both African American males and females from 1935 to 1950, and relatively steady reductions thereafter for females. The smaller declines in male mortality in young adulthood and middle age since the 1950s have led to exceptionally high ratios of male to female mortality at these ages. Corrections for census undercounts lead to higher values of life expectancy than in official life tables, but to less improvement over time. Official estimates of life expectancy at age 65 appear to be about 10% too high around 1940 but only about 1.5% too high in the late 1980s.     

Rethinking a universal framework in the psychiatric symptom-disorder relationship

Research on disparities in health and services should include a critical examination of how social, cultural, and contextual factors affect the connection between symptoms and psychiatric disorders. Systematic differences in this connection by these factors will mean that clinicians using a universalist approach to disorders may make more diagnostic errors for certain patients (e.g., ethnic minorities, the poor). Based on the literature on normative clinical decision-making, this study tests for whether the effect of specific psychiatric disorders on key symptoms is the same for certain groups of the population. The data come from the National Comorbidity Survey. Conditional probabilities of disorders and symptoms, the elements feeding into clinical decision-making, are calculated and tested for equivalence across various racial/ethnic, educational, income, and gender groups. We find some significant differences in the relation of key symptoms to disorders across groups. These findings should encourage testing relativistic frameworks in diagnostic nosology as a step to improve clinical decision-making and reduce diagnostic and treatment disparities in mental health services.     

Managing skunkworks to achieve ambidexterity: The Robinson Crusoe effect

Literature on ambidexterity emphasizes the need for both exploration and exploitation. Large firms usually choose to implement structural ambidexterity to separate both activities. We here focus on an extreme case of such structural partitioning implemented as a secret skunkworks project in a large French automotive company. A qualitative survey using both primary and secondary data shows that the major basic and initial characteristics of a skunkworks (i.e. secrecy, urgency, and autonomy) created favorable conditions for the technological exploration. However, exploitation failed due to precisely those same characteristics coupled with the fact that the project did not respond to a specific market demand: The skunkworks suffered from what we call the "Robinson Crusoe effect." We therefore contribute to the literature on skunkworks, which have remained understudied in the academic literature, as well as on ambidexterity, by showing how the interrelation between different factors is crucial for structural ambidexterity to be successful     

A comparison of classification models to identify the Fragile X Syndrome

The main models of machine learning are briefly reviewed and considered for building a classifier to identify the Fragile X Syndrome (FXS). We have analyzed 172 patients potentially affected by FXS in Andalusia (Spain) and, by means of a DNA test, each member of the data set is known to belong to one of two classes: affected, not affected. The whole predictor set, formed by 40 variables, and a reduced set with only nine predictors significantly associated with the response are considered. Four alternative base classification models have been investigated: logistic regression, classification trees, multilayer perceptron and support vector machines. For both predictor sets, the best accuracy, considering both the mean and the standard deviation of the test error rate, is achieved by the support vector machines, confirming the increasing importance of this learning algorithm. Three ensemble methods - bagging, random forests and boosting - were also considered, amongst which the bagged versions of support vector machines stand out, especially when they are constructed with the reduced set of predictor variables. The analysis of the sensitivity, the specificity and the area under the ROC curve agrees with the main conclusions extracted from the accuracy results. All of these models can be fitted by free R programs.