An application of multivariate total positivity to peacocks

We use multivariate total positivity theory to exhibit new families of peacocks. As the authors of \cite{HPRY}, our guiding example is the result of Carr-Ewald-Xiao \cite{CEX}. We shall introduce the notion of strong conditional monotonicity. This concept is strictly more restrictive than the conditional monotonicity as defined in \cite{HPRY} (see also \cite{Be}, \cite{BPR1} and \cite{ShS1}). There are many random vectors which are strongly conditionally monotone (SCM). Indeed, we shall prove that multivariate totally positive of order 2 (MTP$_2$) random vectors are SCM. As a consequence, stochastic processes with MTP$_2$ finite-dimensional marginals are SCM. This family includes processes with independent and log-concave increments, and one-dimensional diffusions which have absolutely continuous transition kernels.Comment: 29 page

On the public economics of annuities with differential mortality

uncertain lifetime, redistribution, annuities, nonlinear taxation

Temporal patterns in the upstream migration of European eels (Anguilla anguilla) at the Couesnon estuarine dam

The temporal migration patterns of European glass eel Anguilla anguilla at the Couesnon estuarine dam (Mont-Saint-Michel Bay, France)were examined in winter and spring 2004 and 2005. The dam which is located close to the river mouth constitutes a major obstacle for upstreammigrating glass eels. The migration was observed at different temporal scales, from within individual tides to complete tidal cycles between successive spring tides. The maximum number of glass eels arrived downstream of the dam at the beginning and in the middle of the flood tide. Glass eels migrated through the dam openings preferentially from the middle of the flood to the beginning of the ebb tide. Eel densities were highest during the second tide of each tide cycle that arrived at the estuarine dam and when the difference in water level between upstream and downstream of the dam was greatest, particularly at the end of the flood. Analysis of the influence of each environmental factor provided a good prediction of the glass eel recruitment peaks and, therefore, of the most favourable temporal windows for their migration. The water level and temperature were the most important environmental factors. These results provide the information needed for a dam-management program that is compatible with glass eel migration

Determination of the degree of substitution (DS) of mixed cellulose esters by elemental analysis

Equations for transforming the results of elemental analysis (EA) into degree of substitution (DS) values for aliphatic cellulose esters were developed. The equations allow to determine the DS of cellulose derivatives bearing not only one but also two different acyl substituents. Error transmission studies revealed that the accuracy of the DS-values for a pure sample depends on both the number of carbon atoms in the substituents and on the uncertainty of the EA, especially from the hydrogen content. This method provides accurate DS-values (± 0.10 in most cases) if H-content determinations are within ± 0.1

An experimental study of boundary-layer transition induced vibrations on a hydrofoil

This paper aims at characterizing experimentally laminar to turbulent transition induced vibrations. Here, the transition is known to be triggered by a Laminar Separation Bubble that results from a laminar separation of the boundary-layer flow on a hydrofoil. In this study we consider two NACA66312 (Mod) laminar hydrofoils at low angles of incidence (mostly 2° and 4°) and Reynolds numbers ranging from Re=450 000 to 1 200 000, in order to get transitional regimes. The first hydrofoil, made of steel (E=2.1×1011 Pa), is referred to as the rigid hydrofoil, although it is seen to vibrate under the action of the LSB. To better understand the possible interaction between the flow and the foil vibrations, vibration measurements are repeated using a flexible hydrofoil (E=3×109 Pa) of same geometry (under zero loading) and in close configurations. The experiments are carried out at the French Naval Academy Research Institute (IRENav, France). Wall pressure and flow velocity measurements enable a characterization of the laminar separation bubble and the identification of a vortex shedding at a given frequency. It is hence shown that the boundary-layer transition induces important foil vibrations, whose characteristics in terms of frequency and amplitude depend on the vortex shedding frequency, and can be coupled with natural frequencies of the hydrofoils

A Method to Discover Digital Collaborative Conversations in Business Collaborations

Many companies have a suite of digital tools, such as Enterprise Social Networks, conferencing and document sharing software, and email, to facilitate collaboration among employees. During, or at the end of a collaboration, documents are often produced. People who were not involved in the initial collaboration often have difficulties understanding parts of its content because they are lacking the overall context. We argue there is valuable contextual and collaborative knowledge contained in these tools (content and use) that can be used to understand the document. Our goal is to rebuild the conversations that took place over a messaging service and their links with a digital conferencing tool during document production. The novelty in our approach is to combine several conversation-threading methods to identify interesting links between distinct conversations. Specifically we combine header-field information with social, temporal and semantic proximities. Our findings suggest the messaging service and conferencing tool are used in a complementary way. The primary results confirm that combining different conversation threading approaches is efficient to detect and construct conversation threads from distinct digital conversations concerning the same document

The costs of raising children and the effectiveness of policies to support parenthood in European countries: a Literature Review

The purpose of this report is to produce an overview of available knowledge about the following issues:  the costs (to parents) of parenthood and of raising children in European Countries;  the effectiveness, in the short and long term, of various policy measures in avoiding or compensating for those costs; 8  the impact of different policy instruments aimed at supporting families according to various policy objectives, e.g. achieving family projects, reconciling family and working life, reducing child poverty, raising the levels of education and well being of children, and increasing equal opportunities.  the wider economic and social costs and benefits of policy interventions in support of families. The current state of knowledge on the following issues is presented as follows in this review report:  The costs of children and the challenges for public policies supporting parenthood (chapter 1); author: O. Thévenon  The policy instruments used in the EU to support families and reduce the costs of parenthood (Chapter 2); authors: A. Math and O. Thévenon  The impacts of these policies on families: o On fertility and the decision to have children (chapter 3); authors M-Th. Letablier and O. Thévenon o On parents‘ participation in the labour market, gender equality and work-life balance (chapter 4); authors: M-Th. Letablier, A. Luci, O. Thévenon o On children‘s well-being (chapter 5): M-Th. Letablier and O. Thévenon  The wider economic and social costs and benefits of such policies (Chapter 6); author: A. Luci. The review of literature presented in this report attempts to make the tools, goals and impacts of family policies more clear and comparable across countries, in order to facilitate the circulation of knowledge between Member States, notably in the context of the European Alliance for Families and the newly established High Level Experts Group on Demography Issues. The report provides a review of recent literature and available data material on the direct and indirect costs of raising children in the European Union (using international as well as particularly important national studies). Ground breaking studies from countries outside the EU, of particular interest from a methodological point of view, are also included in the review. Focus is on the following kinds of costs of having and raising children over the long and short term: - Direct financial costs, e.g. for housing, health care, education, child care, - Indirect financial costs, e.g. for lost income, lost pension rights, lost career prospects etc. , also taking into account the impact on gender roles and gender equality. The costs of raising children are examined at the different phases of their development, from birth through to the age at which they become autonomous. The overview also summarizes knowledge on the main determinants of costs, including, the effects of the number of children, the socio-economic status of parents, and the family structure. Significant differences in cost levels and structures across Member States are identified. The overview also identifies gaps in the available knowledge, and highlights some issues for future research that have the potential to contribute to a better understanding of the policy impact and to better comparability across the European Union.cost of children; family policies; work and family life reconciliation; fertility; female employment