Adaptive choice of scale tests in flexible two-stage designs with applications in experimental ecology and clinical trials

In this paper, the two-sample scale problem is addressed within the rank framework which does not require to specify the underlying continuous distribution. However, since the power of a rank test depends on the underlying distribution, it would be very useful for the researcher to have some information on it in order to use the possibly most suitable test. A two-stage adaptive design is used with adaptive tests where the data from the first stage are used to compute a selector statistic to select the test statistic for stage 2. More precisely, an adaptive scale test due to Hall and Padmanabhan and its components are considered in one-stage and several adaptive and non-adaptive two-stage procedures. A simulation study shows that the two-stage test with the adaptive choice in the second stage and with Liptak combination, when it is not more powerful than the corresponding one-stage test, shows, however, a quite similar power behavior. The test procedures are illustrated using two ecological applications and a clinical trial.     

Changes in Management Ownership and the Valuation Effects of Equity Offerings

Seasoned equity issues trigger share price declines, and this is usually interpreted as evidence of signalling. We find that seasoned equity issues also typically result in much lower managerial ownership in U.S. firms. Jensen and Meckling (1976) predict a stock price decline when managerial ownership falls. We conduct several tests to distinguish agency explanations form signalling explanations, and conclude that both effects are present.     

Integration,Participation, Identity: Immigrant Associations in the Province of Milan

The paper presents some results from a multi‐year research project on immigrant associations in the province of Milan, Italy. The analysis yields numerous issues for reflection and recurrent features of particular significance. The first is the fact that for all the associations surveyed, their main goal and the essential reason for their existence was the desire to integrate their community of membership into the host society. However, such integration did not consist in a desire to be assimilated into Italian society. Quite the opposite: the majority of the associations studied were wholly committed to maintaining ‐‐ and sometimes rediscovering ‐‐ the identity and culture of their reference community. The second main feature is that immigrant associations are crucial nodes in a dense network of relations involving numerous actors of very different kinds: the immigrants themselves, other immigrant associations, third‐sector organizations, and the local authorities. The third and final important issue concerns the representativeness of immigrant associations: whether, that is, they can be considered the legitimate representatives of the community of membership.     

The Increasing Complexity of Family Relationships: Lifetime Experience of Lone Motherhood and Stepfamilies in Great Britain

We investigate the lifetime incidence and duration oflone motherhood and stepfamilies in Great Britainusing both retrospective and panel informationcontained in the British Household Panel Survey,1991–1995. We find that about 40 per cent of motherswill spend some time as a lone-parent. The duration oflone parenthood is often short, one-half remaininglone-mothers for 4.6 years or less. Aboutthree-fourths of these lone-mothers will form astepfamily, with 80 per cent of these stepfamiliesbeing started by cohabitation and 85 percent followingthe dissolution of a union. Stepfamilies are not verystable: over one-quarter dissolve within one year.Thus, an increasing proportion of today's youngchildren in Britain are likely to experience thechanges, tensions and strains which life inlone-parent families and stepfamilies often entails.The increasing complexity of inter-householdrelationships between children and parents hasimportant implications for the relevance oftheoretical views of the operation of the family putforward by social researchers.     

Pre-commitment and flexibility in a time decision experiment

An agent with dynamically inconsistent preferences may deviate from her plan of action as the future draws near. An exponential discounter may do exactly the same when facing an uncertain future. Through an experiment we compare preference-based vs. uncertainty-based explanations for choice reversal over time by eliciting choices for pre-commitment and flexibility. Evidence of widespread commitment favors a preference-based explanation.

NGOs and international business research: Progress,prospects and problems

Civil society, and non‐government organizations (NGOs) in particular, have become a research interest in international business (IB). The purpose of this paper is to review scholarly understandings of the nature and significance of NGOs in IB. Contributions from complementary research domains are also explored with a view to encouraging greater interdisciplinary integration in analysing the NGO sector and in particular its relations with multinational enterprises (MNEs). These domains are: strategic alliances and resource dependency; global governance and multilateralism; public management; and regulation theory. The primary argument is that such interdisciplinarity may facilitate more innovative IB treatments of the role of NGOs, reflecting more adequately their strategic environment and motivations. Moreover, including a multitude of perspectives helps to address broader issues identified by scholars as pivotal to the future standing of the field: the nature of strategic agency among organizations other than MNEs; the interpretation of globalization and its implications for organizations; and whether IB is too isolated from the other social sciences.     

A “maximum node clustering” problem

In this note we introduce a graph problem, called Maximum Node Clustering (MNC). We prove that the problem (which is easily shown to be strongly NP-complete) can be approximated in polynomial time within a ratio arbitrarily close to 2. For the special case where the graph is a tree, the problem is NP-complete in the ordinary sense; for this case we present a pseudopolynomial algorithm based on dynamic programming, and a related Fully Polynomial Time Approximation Scheme (FPTAS). Also, the tree case is shown to be exactly solvable in time, where n is the number of nodes.