A Parallel Branch and Bound Algorithm for the Maximum Labelled Clique Problem

The maximum labelled clique problem is a variant of the maximum clique problem where edges in the graph are given labels, and we are not allowed to use more than a certain number of distinct labels in a solution. We introduce a new branch-and-bound algorithm for the problem, and explain how it may be parallelised. We evaluate an implementation on a set of benchmark instances, and show that it is consistently faster than previously published results, sometimes by four or five orders of magnitude.Comment: Author-final version. Accepted to Optimization Letter

Watching subgraphs to improve efficiency in maximum clique search

This paper describes a new technique referred to as watched subgraphs which improves the performance of BBMC, a leading state of the art exact maximum clique solver (MCP). It is based on watched literals employed by modern SAT solvers for boolean constraint propagation. In efficient SAT algorithms, a list of clauses is kept for each literal (it is said that the clauses watch the literal) so that only those in the list are checked for constraint propagation when a (watched) literal is assigned during search. BBMC encodes vertex sets as bit strings, a bit block representing a subset of vertices (and the corresponding induced subgraph) the size of the CPU register word. The paper proposes to watch two subgraphs of critical sets during MCP search to efficiently compute a number of basic operations. Reported results validate the approach as the size and density of problem instances rise, while achieving comparable performance in the general case

Treatment with interferon-alpha delays disease in swine infected with a highly virulent CSFV strain

AbstractInterferon-alpha (IFNα) can effectively inhibit or abort a viral infection within the host. It has been reported that IFN induction and production is hindered during classical swine fever virus (CSFV) infection. Most of those studies have been performed in vitro, making it difficult to elucidate the actual role of IFNs during CSFV infection in swine. Here, we report the effect of IFNα treatment (delivered by a replication defective recombinant human adenovirus type 5, Ad5) in swine experimentally infected with highly virulent CSFV strain Brescia. Treatment with two different subtypes of IFNα delayed the appearance of CSF-related clinical signs and virus replication although it did not prevent lethal disease. This is the first report describing the effect of IFNα treatment during CSFV infection in swine

Certifying Solvers for Clique and Maximum Common (Connected) Subgraph Problems

An algorithm is said to be certifying if it outputs, together with a solution to the problem it solves, a proof that this solution is correct. We explain how state of the art maximum clique, maximum weighted clique, maximal clique enumeration and maximum common (connected) induced subgraph algorithms can be turned into certifying solvers by using pseudo-Boolean models and cutting planes proofs, and demonstrate that this approach can also handle reductions between problems. The generality of our results suggests that this method is ready for widespread adoption in solvers for combinatorial graph problems

Venezuelan Equine Encephalitis Replicon Particles Can Induce Rapid Protection against Foot-and-Mouth Disease Virus

We have previously shown that delivery of the porcine type I interferon gene (poIFN-α/β) with a replication-defective human adenovirus vector (adenovirus 5 [Ad5]) can sterilely protect swine challenged with foot-and-mouth disease virus (FMDV) 1 day later. However, the need of relatively high doses of Ad5 limits the applicability of such a control strategy in the livestock industry. Venezuelan equine encephalitis virus (VEE) empty replicon particles (VRPs) can induce rapid protection of mice against either homologous or, in some cases, heterologous virus challenge. As an alternative approach to induce rapid protection against FMDV, we have examined the ability of VRPs containing either the gene for green fluorescent protein (VRP-GFP) or poIFN-α (VRP-poIFN- α) to block FMDV replication in vitro and in vivo. Pretreatment of swine or bovine cell lines with either VRP significantly inhibited subsequent infection with FMDV as early as 6 h after treatment and for at least 120 h posttreatment. Furthermore, mice pretreated with either 107 or 108 infectious units of VRP-GFP and challenged with a lethal dose of FMDV 24 h later were protected from death. Protection was induced as early as 6 h after treatment and lasted for at least 48 h and correlated with induction of an antiviral response and production of IFN- α. By 6 h after treatment several genes were upregulated, and the number of genes and the level of induction increased at 24 h. Finally, we demonstrated that the chemokine IP-10, which is induced by IFN- α and VRP-GFP, is directly involved in protection against FMDV

LEARNING OF THE OBJECT ORIENTED PARADIGM THROUGH INTERACTIVE VIDEO-GAMES DEVELOPMENT

Abstract The Object Orientation Paradigm (OOP) is more than Object Oriented languages. Learning the syntax of a language as C++ or Java is a relatively easy task compared with the understanding of the principles of OO Modeling and Design (OOD), which require a high ability of abstract reasoning. Moreover, it is not enough to teach the artifacts of Computer Aided Software Engineering (CASE) as the Unified Modeling Language (UML) if those principles are not properly understood. We wanted to engage the students in a motivating framework, so both the principles of OOD are properly acquired and put in practice with CASE and programming tools. We found the ideal framework in the development of videogames. Most students are familiar with (even attracted by) them. The existence of powerful yet simple 3D graphical libraries as OpenGL and the portable Window Manager (GLUT), makes very easy the development of quite attractive 3D applications, so the real effort can be done in the OOP. There are two types of games: those with physical simulations (first person shooters, car race, arcade games) and those with logical or reasoning (chess, 4 on a line, etc). Though the second type is interesting, physical systems can be more easily understood and modeled under OOP, because the software and design objects have an equivalent counterpart in the real world. Furthermore physical systems have the added benefit of involving kinematics, dynamics, math, and other disciplines very interesting for the engineering student. At Universidad Politecnica de Madrid, we teach Industrial Informatics which covers both the topics of C++ programming and OOP, starting from a basic knowledge of C language. The subject is taught with 3 hours of C++ theory, 2 hours of OOP theory and 2 hours of practice per week, along a semester, plus a compulsory assignment to be accomplished by the students. We decided to propose the development of a video-game to be carried out along the semester, by groups consisting of two students. Taking into account the required effort, we also decide to restructure the subject around this idea. The practical lessons have been completely modified, leading the student from one practical lesson to the next one in an incremental development of a typical arcade videogame: Pang, in which a player shoots to balls bouncing around the screen. Our focus is the OOP: the application is iteratively built following OOP principles: object creation and destruction, object interaction, relations between classes, GRASP and GOF software patterns, etc. CASE tools and UML are constantly used in this process, in order to support the ideas that motivate our final implementation. The theory and tutorial hours have been also affected: The tutorial time has highly increased, basically overwhelming our capacity. This fact also contributes to the actual understanding of the subject. The theory lessons find the support on the video-games development and practical lessons, making easier for the students to understand the abstract ideas explained in class. We are convinced about the effectiveness of our approach. The motivation of the students has become clearly visible, both in the tutorial lessons and in the high quality of the developed games. The students' grades have clearly improved, not only because of the contribution of the good grades of the game assignment, but also because the understanding of the concepts and the increase of hours dedicated to practical developments

To what extent do fiscal regimes equalize opportunities for income acquisition among citizens?

This project employs the theory of equality of opportunity, described in Roemer’s book (Equality of Opportunity, Harvard University Press, 1998), to compute the extent to which tax-and-transfer regimes in ten countries equalize opportunities among citizens for income acquisition. Roughly speaking, equality of opportunity for incomes has been achieved in a country when it is the case that the distributions of post-fisc income are the same for different types of citizen, where a citizen's type is defined by the socioeconomic status of his parents. Intuitively, a country will have equalized opportunity if the chances of earning high (or low) income are equal for citizens from all family backgrounds. Of course, pre-fisc income distributions, by type, will not be identical, as long as the educational system does not entirely make up for the disadvantage that children, who come from poor families face, but the tax-and-transfer system can play a role in rectifying that inequality. We include, in our computation, two numbers that summarize the extent to which each country’s current fiscal regime achieves equalization of opportunities for income, and the deadweight loss that would be incurred by moving to the regime that does