An exact algorithm for the maximum probabilistic clique problem

The maximum clique problem is a classical problem in combinatorial optimization that has a broad range of applications in graph-based data mining, social and biological network analysis and a variety of other fields. This article investigates the problem when the edges fail independently with known probabilities. This leads to the maximum probabilistic clique problem, which is to find a subset of vertices of maximum cardinality that forms a clique with probability at least \(\theta \in [0,1]\) , which is a user-specified probability threshold. We show that the probabilistic clique property is hereditary and extend a well-known exact combinatorial algorithm for the maximum clique problem to a sampling-free exact algorithm for the maximum probabilistic clique problem. The performance of the algorithm is benchmarked on a test-bed of DIMACS clique instances and on a randomly generated test-bed.     

Alcohol- and drug-involved driving in the United States: methodology for the 2007 National Roadside Survey

This article describes the methodology used in the 2007 U.S. National Roadside Survey to estimate the prevalence of alcohol- and drug-impaired driving and alcohol- and drug-involved driving. This study involved randomly stopping drivers at 300 locations across the 48 continental U.S. states at sites selected through a stratified random sampling procedure. Data were collected during a 2-hr Friday daytime session at 60 locations and during 2-hr nighttime weekend periods at 240 locations. Both self-report and biological measures were taken. Biological measures included breath alcohol measurements from 9,413 respondents, oral fluid samples from 7,719 respondents, and blood samples from 3,276 respondents.     

If happiness is relative, against whom do we compare ourselves? Implications for labour supply

This paper addresses two important issues: the nature of the reference group to which individuals compare themselves, and the implications of social comparisons for labour supply. It identifies age as the main characteristic defining the reference group. Race, sex and religion are other relevant features in its determination. It provides micro-level evidence that social comparisons influence the hours an individual works. Specifically, if her income is lower than her reference group income, she will work more. It also shows that for males, white people and people living in rural areas the effect of relative income on both happiness and labour supply is greater.     

Samir Amin and the challenges of socialist transformation in senile capitalism

ABSTRACT

This article intends to point out strategic dimensions of the thought of Samir Amin. It highlights his analysis of capitalism, of the world system in which it is articulated, and of ways to overcome them in the twenty-first century. He also approaches his reflections on the construction of a V international and his criticisms of those that preceded it.     

‘The Castaways of Life’: A study of organizational remembering within the context of a Chilean Geriatric Hospital

This paper explores the phenomenon of organizational memory within the context of a Chilean Geriatric Hospital that has undergone profound institutional transformations during the last 40 years. The effects of such transformations have reinforced an emphasis on progress at the expense of remembering and integrating the past of the institution as a hospice. The study reveals that this institutional past reverberates in the hospital's working dynamics, which contributes to generating confusion in collective identity, as well as to affect the accomplishment of primary tasks and people's well-being. Access to organizational memory is carried out by the registration of some members' remembering practices about the hospital's past, which are analysed through a hermeneutic method. The study is ethnographic and interpretative, and the recollection of data combines interviews, methods of observation, and the revision of documents.     

A Note on Whittle's Likelihood

The approximate likelihood function introduced by Whittle has been used to estimate the spectral density and certain parameters of a variety of time series models. In this note we attempt to empirically quantify the loss of efficiency of Whittle's method in nonstandard settings. A recently developed representation of some first-order non-Gaussian stationary autoregressive process allows a direct comparison of the true likelihood function with that of Whittle. The conclusion is that Whittle's likelihood can produce unreliable estimates in the non-Gaussian case, even for moderate sample sizes. Moreover, for small samples, and if the autocorrelation of the process is high, Whittle's approximation is not efficient even in the Gaussian case. While these facts are known to some extent, the present study sheds more light on the degree of efficiency loss incurred by using Whittle's likelihood, in both Gaussian and non-Gaussian cases.     

Sensitivity measures of influence on the loading matrix in exploratory factor analysis

For the detection of influential observations on the loading matrix of the factor analysis model, we propose to use the infinitesimal version of two matrix coefficients, including Escoufier (1973)'s also discussed the application in factor analysis of some sensitivity measures used for similar purposes in principal component analysis.