DISCUSSION: A PRODUCER PERSPECTIVE ON THE FUTURE OF DOMESTIC AND TRADE DAIRY POLICY IN CANADA

Agricultural and Food Policy,

Migration-selection balance at multiple loci and selection on dominance and recombination

A steady influx of a single deleterious multilocus genotype will impose genetic load on the resident population and leave multiple descendants carrying various numbers of the foreign alleles. Provided that the foreign types are rare at equilibrium, and that all immigrant genes will eventually be eliminated by selection, the population structure can be inferred explicitly from the deterministic branching process taking place within a single immigrant lineage. Unless the migration and recombination rates were high, this simple method was a very close approximation to the simulated migration-selection balance with all possible multilocus genotypes considered.Comment: includes 6 figures and a Supporting Information. Mathematica notebook where the numerical results were obtained is available upon reques

An Optimal Control Theory for the Traveling Salesman Problem and Its Variants

We show that the traveling salesman problem (TSP) and its many variants may be modeled as functional optimization problems over a graph. In this formulation, all vertices and arcs of the graph are functionals; i.e., a mapping from a space of measurable functions to the field of real numbers. Many variants of the TSP, such as those with neighborhoods, with forbidden neighborhoods, with time-windows and with profits, can all be framed under this construct. In sharp contrast to their discrete-optimization counterparts, the modeling constructs presented in this paper represent a fundamentally new domain of analysis and computation for TSPs and their variants. Beyond its apparent mathematical unification of a class of problems in graph theory, the main advantage of the new approach is that it facilitates the modeling of certain application-specific problems in their home space of measurable functions. Consequently, certain elements of economic system theory such as dynamical models and continuous-time cost/profit functionals can be directly incorporated in the new optimization problem formulation. Furthermore, subtour elimination constraints, prevalent in discrete optimization formulations, are naturally enforced through continuity requirements. The price for the new modeling framework is nonsmooth functionals. Although a number of theoretical issues remain open in the proposed mathematical framework, we demonstrate the computational viability of the new modeling constructs over a sample set of problems to illustrate the rapid production of end-to-end TSP solutions to extensively-constrained practical problems.Comment: 24 pages, 8 figure

Determinants of Desired Career Paths among Canadian Engineers

The goal of this research is to study five career paths available to engineers and to understand what leads them to prefer the management path to other career path possibilities (i.e. the technical path, the project-based path, the entrepreneurial path, and the hybrid path). A questionnaire survey was conducted using a sample of 900 male and female engineers from a large Canadian province. The0501n results show that several determinants under study (mainly individual-related factors, such as career anchors and education) effectively distinguish engineers who want to pursue a management path from those who choose other career paths, especially technical ones Cette recherche vise à étudier six orientations que les ingénieurs peuvent vouloir donner à leur carrière et à comprendre ce qui les amène à privilégier certains choix de carrière. Les possibilités de carrière retenues sont la voie de gestion, la voie technique, la voie de projet, la voie entreprenieuriale, la voie hybride et une nouvelle carrière. Une enquête par questionnaire a été réalisée auprès de 900 ingénieurs à travers le Québec, dont 403 femmes. Les résultats démontrent principalement que plusieurs des facteurs étudiés (principalement les facteurs individuels comme les ancres de carrière et la scolarité) permettent de distinguer efficacement les ingénieurs qui désirent poursuivre une carrière en gestion de ceux qui aspirent à d'autres voies de carrière.Engineers, career, career path, entrepreneurial career, career anchor, Ingénieurs, carrière, voies de carrière, changement de carrière

Polarimetric modeling of corotating interaction regions (CIRs) threading massive-star winds

Massive star winds are complex radiation-hydrodynamic (sometimes magnetohydrodynamic) outflows that are propelled by their enormously strong luminosities. The winds are often found to be structured and variable, but can also display periodic or quasi-periodic behavior in a variety of wind diagnostics. The regular variations observed in putatively single stars, especially in UV wind lines, have often been attributed to corotating interaction regions (CIRs) like those seen in the solar wind. We present light curves for variable polarization from winds with CIR structures. We develop a model for a time-independent CIR based on a kinematical description. Assuming optically thin electron scattering, we explore the range of polarimetric light curves that result as the curvature, latitude, and number of CIRs are varied. We find that a diverse array of variable polarizations result from an exploration of cases. The net polarization from an unresolved source is weighted more toward the inner radii of the wind. Given that most massive stars have relatively fast winds compared to their rotation speeds, CIRs tend to be conical at inner radii, transitioning to a spiral shape at a few to several stellar radii in the wind. Winds with a single CIR structure lead to easily identifiable polarization signatures. By contrast allowing for multiple CIRs, all emerging from a range of azimuth and latitude positions at the star, can yield complex polarimetric behavior. Although our model is based on some simplifying assumptions, it produces qualitative behavior that we expect to be robust, and this has allowed us to explore a wide range of CIR configurations that will prove useful for interpreting polarimetric data.Comment: accepted to A&

Asymmetry measures for QSOs and companions

An asymmetry index is derived from ellipse-fitting to galaxy images, that gives weight to faint outer features and is not strongly redshift-dependent. These measures are made on a sample of 13 2MASS QSOs and their neighbour galaxies, and a control sample of field galaxies from the same wide-field imaging data. The QSO host galaxy asymmetries correlate well with visual tidal interaction indices previously published. The companion galaxies have somewhat higher asymmetry than the control galaxy sample, and their asymmetry is inversely correlated with distance from the QSO. The distribution of QSO-companion asymmetry indices is different from that for matched control field galaxies at the $\sim95$ significance level. We present the data and discuss this evidence for tidal and other disturbances in the vicinity of QSOs.Comment: 13 pages, 2 tables, 4 figures; to appear in A

L'objet des droits constitutionnels à l'égalité

This article is exclusively devoted to enquiring into the purpose of equality rights guaranteed by sections 15 and 28 of the Canadian Charter of Rights and Freedoms. By first retracing the concept of equality from both a legal and philosophical perspective, the author comes to the conclusion that the juxtaposition of values of human dignity and social justice has brought on the most powerful change in the concept of equality. By invoking these two values in unison, authoritative writings, legislators and the courts have on the one hand, come to recognize the insufficiency of formal legal equality and thereby integrate the principle of substantial equality and have, on the other, conceived equality not merely with regard to individuals alone, but also by taking into account groups that society tends to neglect or dominate due to the existence of tenacious prejudices. The author then specifically examines the Canadian legal and socioeconomic context in search of the purpose of equality rights enshrined in the Charter of rights and shows that the addition of section 28 and the enumeration of grounds of discrimination to equality rights in s.s. 15(1) has as its purpose to provide additional protection to women and members of certain underprivileged groups. This special protection is indicative, in the author's view, of a clear constitutional choice in favour of a substantial conception of equality taking into account the collective dimension of discrimination