Isotone additive latent variable models

For manifest variables with additive noise and for a given number of latent variables with an assumed distribution, we propose to nonparametrically estimate the association between latent and manifest variables. Our estimation is a two step procedure: first it employs standard factor analysis to estimate the latent variables as theoretical quantiles of the assumed distribution; second, it employs the additive models’ backfitting procedure to estimate the monotone nonlinear associations between latent and manifest variables. The estimated fit may suggest a different latent distribution or point to nonlinear associations. We show on simulated data how, based on mean squared errors, the nonparametric estimation improves on factor analysis. We then employ the new estimator on real data to illustrate its use for exploratory data analysis.     

Adaptive shrinkage of singular values

To recover a low-rank structure from a noisy matrix, truncated singular value decomposition has been extensively used and studied. Recent studies suggested that the signal can be better estimated by shrinking the singular values as well. We pursue this line of research and propose a new estimator offering a continuum of thresholding and shrinking functions. To avoid an unstable and costly cross-validation search, we propose new rules to select two thresholding and shrinking parameters from the data. In particular we propose a generalized Stein unbiased risk estimation criterion that does not require knowledge of the variance of the noise and that is computationally fast. A Monte Carlo simulation reveals that our estimator outperforms the tested methods in terms of mean squared error on both low-rank and general signal matrices across different signal-to-noise ratio regimes. In addition, it accurately estimates the rank of the signal when it is detectable.     

An ergonomic approach to improve work conditions of older employees in social housing

French companies are legally required to develop action plans to improve employment and work conditions for older workers ("plans seniors"). These plans contain measures oriented towards recruiting, career evolution, skills developme1nt, knowledge transmission and improvement of work conditions. A tool for assessing work situations experienced by council buildings caretakers ("gardiens") was used in such a plan on behalf of the main agency of council housing in Paris, and we developed. This assessment tool was developed after ergonomic work analysis on a sample of 36 older caretakers (age > 57 y.o). The technical inspectors in charge of technical interventions on buildings and managing caretakers were trained to use the assessment tool and apply it to all caretakers aged 50 and over.     

ADE-4: a multivariate analysis and graphical display software

We present ADE-4, a multivariate analysis and graphical display software. Multivariate analysis methods available in ADE-4 include usual one-table methods like principal component analysis and correspondence analysis, spatial data analysis methods (using a total variance decomposition into local and global components, analogous to Moran and Geary indices), discriminant analysis and within/between groups analyses, many linear regression methods including lowess and polynomial regression, multiple and PLS (partial least squares) regression and orthogonal regression (principal component regression), projection methods like principal component analysis on instrumental variables, canonical correspondence analysis and many other variants, coinertia analysis and the RLQ method, and several three-way table (k-table) analysis methods. Graphical display techniques include an automatic collection of elementary graphics corresponding to groups of rows or to columns in the data table, thus providing a very efficient way for automatic k-table graphics and geographical mapping options. A dynamic graphic module allows interactive operations like searching, zooming, selection of points, and display of data values on factor maps. The user interface is simple and homogeneous among all the programs; this contributes to making the use of ADE-4 very easy for non- specialists in statistics, data analysis or computer science.     

Top Ten Challenges for Understanding Gender and Aggression in Children: Why Can’t We All Just Get Along?

This essay identifies ten significant methodological challenges for understanding aggression and gender. In light of the recent explosion of research on indirect/relational/social aggression, it seems important to clarify gaps in our current understanding and to identify promising methods by which better answers might be found. The discussion begins with basic issues of definitions, contexts and subtypes, moves on to points concerning sampling and measures, and addresses whether current evidence warrants deciding that girls are as aggressive as boys. We conclude that although research has shown that the majority of girls' aggression takes indirect/relational/social forms, it is premature to conclude that boys do not also engage in these behaviors. We caution against assuming that physical and indirect/relational/social aggression are comparable in their developmental origins and consequences, and urge researchers to consider that fully understanding indirect/relational/social aggression might require different conceptual frameworks and research methods.     

Reduced costs propagation in an efficient implicit enumeration for the 01 multidimensional knapsack problem

In a previous work we proposed a variable fixing heuristics for the 0-1 Multidimensional knapsack problem (01MDK). This approach uses fractional optima calculated in hyperplanes which contain the binary optimum. This algorithm obtained best lower bounds on the OR-Library benchmarks. Although it is very attractive in terms of results, this method does not prove the optimality of the solutions found and may fix variables to a non-optimal value. In this paper, we propose an implicit enumeration based on a reduced costs analysis which tends to fix non-basic variables to their exact values. The combination of two specific constraint propagations based on reduced costs and an efficient enumeration framework enable us to fix variables on the one hand and to prune significantly the search tree on the other hand. Experimentally, our work provides two main contributions: (1) we obtain several new optimal solutions on hard instances of the OR-Library and (2) we reduce the bounds of the number of items at the optimum on several harder instances.     

Recruteurs sous tensions. Discrimination et diversité au prisme de registres argumentaires enchevêtrés

While most studies on discriminatory practices in recruitment identify them with a single set of motives, this article, based on 57 interviews with recruiters from different sectors, seeks to provide an alternative analytical framework. The requirements for fairness in the recruitment process are taken seriously and used to describe an experience of recruitment that entails grappling with contradictory demands, some related to economic efficiency, others to social justice. Recruiters have to balance these requirements. And whether or not recruitment is discriminatory depends on how the balance is struck and the social and organisational constraints that affect it.     

Return to work with chronic low back pain: using an evidence-based approach along with the occupational therapy framework

This paper will attempt to apply the occupational therapy framework [1] along with an evidence-based approach and an occupation-based intervention with a population of workers with chronic low back pain (CLBP) to help them return to work and maintain their work status. This paper will focus primarily on those clients with CLBP who still have a link to their employment but who do not perceive themselves as being capable to go back to their job despite conflicting opinions from other stakeholders (primary health care professionals, employer or insurer). They are being evaluated in occupational therapy shortly before return to work and followed until their optimal functional capacities are reached. This means that either all functional goals related to the actual physical demands of their job have been reached or that further treatment does not result in functional improvement.     

From Decolonization to Postcolonial Management: Challenging Heritage Administration and Governance in New Zealand

In the 1990s, we witnessed the rise of a new form of management over cultural affairs in the Americas and Oceania as their respective indigenous populations strove for greater participation in governance. This article illustrates the characteristics of this new current in the public sector by examining recent innovations in heritage administration and governance in New Zealand. In particular, this paper deals with organizational, managerial, and professional practices in New Zealand??s cultural sector by focusing on the Museum of New Zealand and the partnership between the Ministry for Culture and Heritage and the indigenous M??ori community.