Can Computer Algebra be Liberated from its Algebraic Yoke ?

So far, the scope of computer algebra has been needlessly restricted to exact algebraic methods. Its possible extension to approximate analytical methods is discussed. The entangled roles of functional analysis and symbolic programming, especially the functional and transformational paradigms, are put forward. In the future, algebraic algorithms could constitute the core of extended symbolic manipulation systems including primitives for symbolic approximations.Comment: 8 pages, 2-column presentation, 2 figure

The impact of policies on the division of labour : a new approach

There are considerable differences between most European countries in respect both of the division of labour within families and the policies that seek to influence that division. These policies are based, implicitly or explicitly, on assumptions about what constitutes an effective policy measure. However, little is known about how to measure the effects of such policies on the division of labour. Moreover, the emergence of a supranational political entity, i.e. the European Union, requires a new approach to the evaluation of national policies. In this article, the authors put forward a theoretical framework to be used in an international study of the effects of policies on the division of paid and unpaid work in EU member states. This proposed framework will be empirically tested in a research project to be conducted in the next few years by members of a European network of social scientists who have been working together since 1995.division of labour;government policy;unpaid work;domestic work

Martha A. Finemanand legal equality: Vulnerability vs. Subordiscrimination?

This article analyzes (and argues) the American legal scholar Martha A. Fineman's thesis about vulnerability. It is divided into five sections in which Fineman's paradigm is successively contextualized, projected to the ECtHR cases on vulnerability and compared with other critical contributions to Antidiscrimination Law. It ends with a brief conclusion that, while recognizing the validity of the diagnosis and the laudable purpose that moves Fineman's theory, it is critical about taking it as inspiration for a new and necessary concept of legal equality

Vortex dynamics under pulsatile flow in axisymmetric constricted tubes

An improved understanding of how vortices develop and propagate under pulsatile flow can shed important light on the mixing and transport processes including the transition to turbulent regime occurring in such systems. For example, the characterization of pulsatile flows in obstructed artery models serves to encourage research into flow-induced phenomena associated with changes in morphology, blood viscosity, wall elasticity and flow rate. In this work, an axisymmetric rigid model was used to study the behaviour of the flow pattern with varying constriction degree ($d_0$), mean Reynolds number ($\bar{Re}$) and Womersley number ($\alpha$). Velocity fields were acquired experimentally using Digital Particle Image Velocimetry and generated numerically. For the acquisition of data, $\bar{Re}$ was varied from 385 to 2044, $d_0$ was 1.0 cm and 1.6 cm, and $\alpha$ was varied from 17 to 33 in the experiments and from 24 to 50 in the numerical simulations. Results for the considered Reynolds number, showed that the flow pattern consisted of two main structures: a central jet around the tube axis and a recirculation zone adjacent to the inner wall of the tube, where vortices shed. Using the vorticity fields, the trajectory of vortices was tracked and their displacement over their lifetime calculated. The analysis led to a scaling law equation for the maximum vortex displacement as a function of a dimensionless variable dependent on the system parameters Re and $\alpha$

Managing Break-The-Glass using Situation-oriented authorizations

National audienceThe patient's life is a redline in Healthcare environments. Whenever it comes to danger, such environments reject static authorizations . A common problem "Break The Glass" is known as the act of breaking the static authorization in order to reach the required permission. Healthcare environment is full of different contexts and situations that require the authorizations to be dynamic. Dynamic Authorization is a concept of giving the choice to E-Health authorization system to choose the most suitable permission by considering one's situation. This paper aims at preventing the matter of modifying the policy to make authorizations dynamic. It introduces a simple solution to provide Dynamic Authorization by orienting the authorization system decision using situations. Situations, which are calculated using Complex Event Processing, are integrated to XACML architecture. A Healthcare example proves the efficiency of our approach

Machine-assisted Cyber Threat Analysis using Conceptual Knowledge Discovery

Over the last years, computer networks have evolved into highly dynamic and interconnected environments, involving multiple heterogeneous devices and providing a myriad of services on top of them. This complex landscape has made it extremely difficult for security administrators to keep accurate and be effective in protecting their systems against cyber threats. In this paper, we describe our vision and scientific posture on how artificial intelligence techniques and a smart use of security knowledge may assist system administrators in better defending their networks. To that end, we put forward a research roadmap involving three complimentary axes, namely, (I) the use of FCA-based mechanisms for managing configuration vulnerabilities, (II) the exploitation of knowledge representation techniques for automated security reasoning, and (III) the design of a cyber threat intelligence mechanism as a CKDD process. Then, we describe a machine-assisted process for cyber threat analysis which provides a holistic perspective of how these three research axes are integrated together

Liposomal clodronate inhibition of osteoclastogenesis and osteoinduction by submicrostructured beta-tricalcium phosphate

Bone graft substitutes such as calcium phosphates are subject to the innate inflammatory reaction, which may bear important consequences for bone regeneration. We speculate that the surface architecture of osteoinductive β-tricalcium phosphate (TCP) stimulates the differentiation of invading monocyte/macrophages into osteoclasts, and that these cells may be essential to ectopic bone formation. To test this, porous TCP cubes with either submicron-scale surface architecture known to induce ectopic bone formation (TCPs, positive control) or micron-scale, non-osteoinductive surface architecture (TCPb, negative control) were subcutaneously implanted on the backs of FVB strain mice for 12 weeks. Additional TCPs samples received local, weekly injections of liposome-encapsulated clodronate (TCPs + LipClod) to deplete invading monocyte/macrophages. TCPs induced osteoclast formation, evident by positive tartrate resistant acid phosphatase (TRAP) cytochemical staining and negative macrophage membrane marker F4/80 immunostaining. No TRAP positive cells were found in TCPb or TCPs + LipClod, only F4/80 positive macrophages and foreign body giant cells. TCPs stimulated subcutaneous bone formation in all implants, while no bone could be found in TCPb or TCPs + LipClod. In agreement, expression of bone and osteoclast gene markers was upregulated in TCPs versus both TCPb and TCPs + LipClod, which were equivalent. In summary, submicron-scale surface structure of TCP induced osteoclastogenesis and ectopic bone formation in a process that is blocked by monocyte/macrophage depletion

Strontium-substituted apatite coating grown on Ti6Al4V substrate through biomimetic synthesis

During the last few years Strontium has been shown to have beneficial effects when incorporated at certain doses in bone by stimulating bone formation. It is believed that its presence locally at the interface between an implant and bone will enhance osteointegration and therefore, ensure the longevity of a joint prosthesis. In this study we explore the possibility of incorporating Sr into nano-apatite coatings prepared by a solution-derived process according to an established biomimetic methodology for coating titanium based implants. The way this element is incorporated in the apatite structure and its effects on the stereochemistry and morphology of the resulting apatite layers was investigated, as well as its effect in the mineralization kinetics. By using the present methodology it was possible to incorporate increasing amounts of Sr in the apatite layers. Sr was found to incorporate in the apatite layer through a substitution mechanism by replacing Ca in the apatite lattice. The presence of Sr in solution induced an inhibitory effect on mineralization, leading to a decrease in the thickness of the mineral layers. The obtained Sr-substituted biomimetic coatings presented a bone-like structure similar to the one found in the human bone and therefore, are expected to enhance bone formation and osteointegration