Finding a Box Representation for a Graph in $O(n^2\Delta^2\ln n)$ time

An axis-parallel box in $b$-dimensional space is a Cartesian product $R_1 \times R_2 \times \cdots \times R_b$ where $R_i$ (for $1 \leq i \leq b$) is a closed interval of the form $[a_i, b_i]$ on the real line. For a graph $G$, its boxicity is the minimum dimension $b$, such that $G$ is representable as the intersection graph of (axis-parallel) boxes in $b$-dimensional space. The concept of boxicity finds application in various areas of research like ecology, operation research etc. Chandran, Francis and Sivadasan gave an $O(\Delta n^2 \ln^2 n)$ randomized algorithm to construct a box representation for any graph $G$ on $n$ vertices in $\lceil (\Delta + 2)\ln n \rceil$ dimensions, where $\Delta$ is the maximum degree of the graph. They also came up with a deterministic algorithm that runs in $O(n^4 \Delta )$ time. Here, we present an $O(n^2 \Delta^2 \ln n)$ deterministic algorithm that constructs the box representation for any graph in $\lceil (\Delta + 2)\ln n \rceil$ dimensions.

Features of a unique intronless cluster of class I small heat shock protein genes in tandem with box C/D snoRNA genes on chromosome 6 in tomato (Solanum lycopersicum)

Physical clustering of genes has been shown in plants; however, little is known about gene clusters that have different functions, particularly those expressed in the tomato fruit. A class I 17.6 small heat shock protein (Sl17.6 shsp) gene was cloned and used as a probe to screen a tomato (Solanum lycopersicum) genomic library. An 8.3-kb genomic fragment was isolated and its DNA sequence determined. Analysis of the genomic fragment identified intronless open reading frames of three class I shsp genes (Sl17.6, Sl20.0, and Sl20.1), the Sl17.6 gene flanked by Sl20.1 and Sl20.0, with complete 5' and 3' UTRs. Upstream of the Sl20.0 shsp, and within the shsp gene cluster, resides a box C/D snoRNA cluster made of SlsnoR12.1 and SlU24a. Characteristic C and D, and C' and D', boxes are conserved in SlsnoR12.1 and SlU24a while the upstream flanking region of SlsnoR12.1 carries TATA box 1, homol-E and homol-D box-like cis sequences, TM6 promoter, and an uncharacterized tomato EST. Molecular phylogenetic analysis revealed that this particular arrangement of shsps is conserved in tomato genome but is distinct from other species. The intronless genomic sequence is decorated with cis elements previously shown to be responsive to cues from plant hormones, dehydration, cold, heat, and MYC/MYB and WRKY71 transcription factors. Chromosomal mapping localized the tomato genomic sequence on the short arm of chromosome 6 in the introgression line (IL) 6-3. Quantitative polymerase chain reaction analysis of gene cluster members revealed differential expression during ripening of tomato fruit, and relatively different abundances in other plant parts.

Genetic analysis of an Indian family with members affected with Waardenburg syndrome and Duchenne muscular dystrophy

Purpose: Waardenburg syndrome (WS) is characterized by sensorineural hearing loss and pigmentation defects of the eye, skin, and hair. It is caused by mutations in one of the following genes: PAX3 (paired box 3), MITF (microphthalmia-associated transcription factor), EDNRB (endothelin receptor type B), EDN3 (endothelin 3), SNAI2 (snail homolog 2, Drosophila) and SOX10 (SRY-box containing gene 10). Duchenne muscular dystrophy (DMD) is an X-linked recessive disorder caused by mutations in the DMD gene. The purpose of this study was to identify the genetic causes of WS and DMD in an Indian family with two patients: one affected with WS and DMD, and another one affected with only WS. Methods: Blood samples were collected from individuals for genomic DNA isolation. To determine the linkage of this family to the eight known WS loci, microsatellite markers were selected from the candidate regions and used to genotype the family. Exon-specific intronic primers for EDN3 were used to amplify and sequence DNA samples from affected individuals to detect mutations. A mutation in DMD was identified by multiplex PCR and multiplex ligation-dependent probe amplification method using exon-specific probes. Results: Pedigree analysis suggested segregation of WS as an autosomal recessive trait in the family. Haplotype analysis suggested linkage of the family to the WS4B (EDN3) locus. DNA sequencing identified a novel missense mutation p.T98M in EDN3. A deletion mutation was identified in DMD. Conclusions: This study reports a novel missense mutation in EDN3 and a deletion mutation in DMD in the same Indian family. The present study will be helpful in genetic diagnosis of this family and increases the mutation spectrum of EDN3.

A comprehensive analysis of the chorion locus in silkmoth

Despite more than 40 years of intense study, essential features of the silkmoth chorion (eggshell) are still not fully understood. To determine the precise structure of the chorion locus, we performed extensive EST analysis, constructed a bacterial artificial chromosome (BAC) contig, and obtained a continuous genomic sequence of 871,711 base pairs. We annotated 127 chorion genes in two segments interrupted by a 164 kb region with 5 non-chorion genes, orthologs of which were on chorion bearing scaffolds in 4 ditrysian families. Detailed transcriptome analysis revealed expression throughout choriogenesis of most chorion genes originally categorized as ``middle'', and evidence for diverse regulatory mechanisms including cis-elements, alternative splicing and promoter utilization, and antisense RNA. Phylogenetic analysis revealed multigene family associations and faster evolution of early chorion genes and transcriptionally active pseudogenes. Proteomics analysis identified 99 chorion proteins in the eggshell and micropyle localization of 1 early and 6 Hc chorion proteins.

Physical constraints, fundamental limits, and optimal locus of operating points for an inverted pendulum based actuated dynamic walker

The inverted pendulum is a popular model for describing bipedal dynamic walking. The operating point of the walker can be specified by the combination of initial mid-stance velocity (v(0)) and step angle (phi(m)) chosen for a given walk. In this paper, using basic mechanics, a framework of physical constraints that limit the choice of operating points is proposed. The constraint lines thus obtained delimit the allowable region of operation of the walker in the v(0)-phi(m) plane. A given average forward velocity v(x,) (avg) can be achieved by several combinations of v(0) and phi(m). Only one of these combinations results in the minimum mechanical power consumption and can be considered the optimum operating point for the given v(x, avg). This paper proposes a method for obtaining this optimal operating point based on tangency of the power and velocity contours. Putting together all such operating points for various v(x, avg,) a family of optimum operating points, called the optimal locus, is obtained. For the energy loss and internal energy models chosen, the optimal locus obtained has a largely constant step angle with increasing speed but tapers off at non-dimensional speeds close to unity.

The plastic collapse and energy absorption capacity of egg-box panels

The plastic collapse response of aluminium egg-box panels subjected to out-of-plane compression has been measured and modelled. It is observed that the collapse strength and energy absorption are sensitive to the level of in-plane constraint, with collapse dictated either by plastic buckling or by a travelling plastic knuckle mechanism. Drop weight tests have been performed at speeds of up to 6 m s-1, and an elevation in strength with impact velocity is noted. A 3D finite element shell model is needed in order to reproduce the observed behaviours. Additional calculations using an axisymmetric finite element model give the correct collapse modes but are less accurate than the more sophisticated 3D model. The finite element simulations suggest that the observed velocity dependence of strength is primarily due to strain-rate sensitivity of the aluminium sheet, with material inertia playing a negligible role. Finally, it is shown that the energy absorption capacity of the egg-box material is comparable to that of metallic foams. © 2003 Elsevier Ltd. All rights reserved.

Les attributs et contextes d'utilisation du travail collaboratif

Résumé: Le travail collaboratif s’invite à présent partout, et est identifié dans des domaines aussi multiples que variés. Dans le monde de l’entreprise, de la prise en charge médico-sociale, de l’éducation / formation, de la recherche, de l’économie, de la politique, de la gestion de carrière… etc. Ce travail vise dans un premier temps à décliner ce qu’est la collaboration, ses caractéristiques, ses contextes d’utilisation, et la façon dont elle se différencie des autres formes d’organisation (coopération et compétition notamment). Dans un deuxième temps, il réexamine la question de la nouveauté du travail collaboratif à la lumière des résultats obtenus. S’il est assez évident que les « ingrédients », les attributs du travail collaboratif ne sont pas nouveaux (le développement informatique mis à part), il semble en revanche que les combinaisons rencontrées et les domaines d’application génèrent de nouvelles questions. Pour finir, en s’inspirant des termes associés à collaboration, il considère quelques-uns des nouveaux enjeux dans la sphère professionnelle.

Entre Syrie et Mésopotamie : vases zoomorphes du Règne de Mittani

Abstract: The Mittanian zoomorphic vessels from Nuzi, Tell Brak, Tell al-Rimah and other sites allow the creation of a significant database for analysis based on typological criteria as well as spatial distribution. This class of materials is attested in several areas of the ancient Near East from the Late Calcholitic and still produced until the Mittanian age and thereafter. Most of the finds come from temples or domestic contexts and they can be now securely dated, while their spatial distribution can be properly investigated. Lion representations seem to predominate, but pigs and other animals appear as well. The exact function and meaning of these vessels are difficult to ascertain, nevertheless, in most cases, they are probably related to cultic practices performed throughout the Mittanian Empire.

La precarite de l’emploi et ses multiples impacts a la lumière du genre

Résumé: A l’heure où l’on évoque une “génération précaire” il est intéressant de s’interroger sur l’accroissement de la précarité de l’emploi en France et d’étudier ses éventuels effets sur les salariés. L’objectif de la présente recherche était d’observer les impacts causés par la précarité de l’emploi sur une population de référence et voir si ces effets différaient selon le sexe du salarié soumis à la précarité. Pour ce faire, nous avons soumis un questionnaire à deux groupes de travailleurs. Ce dernier portait sur la précarité de l’emploi et ses impacts en termes de stress, consommation de substances et impacts sur la sphère privée. Les résultats font apparaître des effets significatifs et des tendances qui existent sur certaines des dimensions interrogées (stress et consommation) entre le groupe de travailleurs précaires et non précaires. De plus, des effets entre hommes et femmes ont également été relevés. Par contre, nous n’avons pas d’effets observés sur la sphère privée de l’individu. Suite à l’absence d’effet constaté nous interrogeons la spécificité de la population. Aussi, nous envisageons de prolonger cette étude sur la recherche d’indicateurs concernant la précarité enseignante. Mots clés: précarité professionnelle, précarité du travail, précarité de l’emploi, travailleurs précaires, inégalités hommes femmes, stress, substances addictives, impact vie hors travail

Modelling of Laminar Plasma Jet Impinging on a Flatplate with Approximate Box Relaxation Method

Approximate Box Relaxation method was used t'o simulate a plasma jet flow impinging on a flatplate at atmospheric pressure, to achieve a better understanding of the characteristics of plasma jet in materials surface treating. The flow fields under different conditions were simulated and analyzed. The distributions of temperature, velocity and pressure were obtained by modelling. Computed results indicate that this numerical method is suitable for simulation of the flow characteristics of plasma jet: and is helpful for understanding of the mechanism of the plasma-material processing.

Creencias de control con respecto a la salud del feto : estructura factorial y fiabilidad de una adaptación al castellano de la Escala Fetal Health Locus of Control (FHLC)

Resumen: Este estudio presenta la estructura factorial y la evaluación de la fiabilidad de una versión en castellano de la escala Fetal Health Locus of Control, que evalúa creencias de control vinculadas a la salud del feto basándose en el concepto Locus de Control acuñado por Rotter. La escala fue administrada a mujeres en edad reproductiva (N = 130) en instituciones educativas de la ciudad de Santa Fe. La versión adaptada de la escala muestra una estructura de 3 factores principales que se corresponden con los constructos teóricos en los que se basa la escala original. La consistencia interna evaluada a través del alpha de Cronbach resultó adecuada, con valores de .81 para la subescala FHLCE-D, .75 para la subescala FHLCI y .76 para la subescala FHLCE-P. En conclusión, la versión adaptada de la escala posee propiedades psicométricas satisfactorias, similares a las de escala original.

Locus amoenus et locus horribilis : topografía mágica en la literatura caballeresca española

Resumen: El espacio otorga al héroe la posibilidad de situarse en determinado lugar para que se produzca el contacto con la aventura; el espacio resulta, entonces, escenario de las hazañas del caballero y de los logros que producen el perfeccionamiento de sus virtudes. Estos lugares no siempre tienen características edénicas, a veces se manifiestan como auténticos infiernos en los que la aventura se convierte en un verdadero suplicio. Este trabajo tratará de enunciar una posible clasificación de los diferentes lugares mágicos en los que el caballero tiene su encuentro inesperado con lo Otro

La souffrance émotionnelle des personnels d’intervention : résultats préliminaires de l’étude sur la santé et la qualité de vie au travail dans les métiers du secteur de l’aide et du soin à domicile

Resumen: La prolongación de la edad y el aumento de la expectativa de vida han hecho surgir nuevas necesidades de atención para las personas ancianas y ello ha inducido a la ampliación de las prestaciones de servicios a domicilio. En este sentido, el trabajo de estos profesionales de intervención a domicilio, así como sus misiones, están en plena mutación. Es un sector con dificultades, debido a la dificultad de reclutar un personal especializado y al absentismo inquietante. Después de un análisis sobre el estado de este sector de la profesión en el que se establece la diferencia entre el enfoque físico y el psicológico sobre la salud, nuestra reflexión se centra en los riesgos psicosociales de esta población de profesionales. Se presentan los resultados preliminares de la investigación realizada con una muestra de 38 personas que ejercían laboralmente en este sector. Emerge la expresión de un sufrimiento emocional, en la que el aislamiento de los participantes es uno de los factores que caracterizan los oficios identificados con una fuerte dimensión relacional con personas vulnerables. La dimensión asistencial del trabajo se presenta como fuente de satisfacción del oficio pero, a su vez, puede conducir a una dificultad de gestionar acontecimientos no previstos