Les tâches de l'OIT à l'heure de son centenaire

Les principes – énoncés dans sa Constitution et dans la Déclaration de Philadelphie – qui définissent les missions de l'OIT n'ont rien perdu de leur valeur ni de leur actualité. En revanche, les conditions dans lesquelles ces missions s'exercent ont profondément changé. Le monde du travail est aujourd'hui le théâtre de bouleversements écologiques, technologiques et institutionnels, qui sont autant de défis à relever. La contribution de l'OIT à cette tâche devrait s'ordonner autour de trois principes, dont la mise en œuvre correspond à ses missions constitutionnelles: les principes de solidarité, de démocratie économique et de responsabilité socio-écologique.     

Urbanization impacts the taxonomic and functional structure of aquatic macroinvertebrate communities in a small Neotropical city

Due to habitat fragmentation, resource disruption and pollution, urbanization is one of the most destructive forms of anthropization affecting ecosystems worldwide. Generally, human-mediated perturbations dramatically alter species diversity in urban sites compared to the surroundings, thus influencing the functioning of the entire ecosystem. We investigated the taxonomic and functional diversity patterns of the aquatic macroinvertebrate communities in tank bromeliads by comparing those found in a small Neotropical city with those from an adjacent rural site. Changes in the quality of detrital inputs in relation to lower tree diversity and the presence of synanthropic species are likely important driving forces behind the observed structural changes in the urban site. Leaf-litter processors (i.e., shredders, scrapers) were positively affected in the urban site, while filter-feeders that process smaller particles produced by the activity of the shredders were negatively affected. Because we cannot ascertain whether the decline in filter-feeders is related to food web-mediated effects or to competitive exclusion (Aedes aegypti mosquitoes were present in urban bromeliads only), further studies are necessary to account for the effects of intra-guild competition or inter-guild facilitation.     

On Combining Wavelets Expansion and Sparse Linear Models for Regression on Metabolomic Data and Biomarker Selection

Wavelet thresholding of spectra has to be handled with care when the spectra are the predictors of a regression problem. Indeed, a blind thresholding of the signal followed by a regression method often leads to deteriorated predictions. The scope of this article is to show that sparse regression methods, applied in the wavelet domain, perform an automatic thresholding: the most relevant wavelet coefficients are selected to optimize the prediction of a given target of interest. This approach can be seen as a joint thresholding designed for a predictive purpose. The method is illustrated on a real world problem where metabolomic data are linked to poison ingestion. This example proves the usefulness of wavelet expansion and the good behavior of sparse and regularized methods. A comparison study is performed between the two-steps approach (wavelet thresholding and regression) and the one-step approach (selection of wavelet coefficients with a sparse regression). The comparison includes two types of wavelet bases, various thresholding methods, and various regression methods and is evaluated by calculating prediction performances. Information about the location of the most important features on the spectra was also obtained and used to identify the most relevant metabolites involved in the mice poisoning.     

CONTROL: the extractive ecology of corn monoculture

This article tells the history of the industrial and biotechnological development of large-scale corn agriculture, from a new materialist perspective. Addressing the large-scale economy of industrial food production as a form of more-than-human configuration, it demonstrates how corn has been made into a quintessential commodity and factor of production for a consumption-based economy. Set within discourses around the climate crisis, this account critically assesses the Anthropocene and its advocacy for human accountability in regards to the exploitation of nonhuman matters. I ask: who is the Anthropos? How does it/he/she meet with its domesticated subjects, or rather makes them into domesticable materials? Telling the history of corn monoculture from a new materialist standpoint exposes this industry’s distribution of agency, power and control across a diversity of human and nonhuman actors. This is at the centre of this article’s three sections: (1) an argument for inscribing extractivism within new materialist literature, (2) an account of the industrialization of corn monoculture, exposing the industry’s main mechanisms and economic endeavours, as well as its ramifications with a biopolitics of invasion and (3) the biotechnological development of the industry and its shifts from a biopolitics of vegetal matter to an informational extractivism and a necropolitics of killable life. Thus I argue that if the industry of corn monoculture belongs to a broader network of detrimental industries characteristic of the Anthropocene, the geological Anthropos is not to be understood as synonymous with the human species, but as a very restrictive ecology of humans and nonhumans, including corporate, industrial, technoscientific and extractive actors. As such, the article emphasizes the moral necessity of rupturing with the narrative of the Anthropocene, a discourse better suited for supporting existing mechanisms of domination and exploitation constitutive of the economy of climate change.     

Parameter selection in modified histogram estimates

A multivariate modified histogram density estimate depending on a reference density g and a partition P has been proved to have good consistency properties according to several information theoretic criteria. Given an i.i.d. sample, we show how to select automatically both g and P so that the expected L ₁ error of the corresponding selected estimate is within a given constant multiple of the best possible error plus an additive term which tends to zero under mild assumptions. Our method is inspired by the combinatorial tools developed by Devroye and Lugosi [Devroye, L. and Lugosi, G., 2001, Combinatorial Methods in Density Estimation (New York, NY: Springer–Verlag)] and it includes a wide range of reference density and partition models. Results of simulations are also presented.     

Tribute to Jean-Yves Jaffray

Tribute to Jean-Yves Jaffray by the French Group of Decision Theory.     

Lower bounds and a tabu search algorithm for the minimum deficiency problem

An edge coloring of a graph G=(V,E) is a function c:E→ℕ that assigns a color c(e) to each edge e∈E such that c(e)≠c(e′) whenever e and e′ have a common endpoint. Denoting S _v (G,c) the set of colors assigned to the edges incident to a vertex v∈V, and D _v (G,c) the minimum number of integers which must be added to S _v (G,c) to form an interval, the deficiency D(G,c) of an edge coloring c is defined as the sum ∑ _v∈V D _v (G,c), and the span of c is the number of colors used in c. The problem of finding, for a given graph, an edge coloring with a minimum deficiency is NP-hard. We give new lower bounds on the minimum deficiency of an edge coloring and on the span of edge colorings with minimum deficiency. We also propose a tabu search algorithm to solve the minimum deficiency problem and report experiments on various graph instances, some of them having a known optimal deficiency.     

Optimal Ordering Policies for Stochastic Inventory Problems with Observed Information Delays

Information delays exist in an inventory system when it takes time to collect, process, validate, and transmit inventory/demand data. A general framework is developed in this paper to describe information flows in an inventory system with information delays. We characterize the sufficient statistics for making optimal decisions. When the ordering cost is linear, the optimality of a state‐dependent base‐stock policy is established even when information flows are allowed to cross over time. Additional insights into the problem are obtained via a comparison between our models and the models with stochastic order lead times. We also show that inventory can substitute for information and vice versa.