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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.sysarc.2004.10.008 Byline: Arnaud Giersch (a), Yves Robert (b), Frederic Vivien (b) Keywords: Scheduling; Heterogeneous clusters; Independent tasks; File-sharing; Heuristics Abstract: This paper is devoted to scheduling a large collection of independent tasks onto heterogeneous clusters. The tasks depend upon (input) files which initially reside on a master processor. A given file may well be shared by several tasks. The role of the master is to distribute the files to the processors, so that they can execute the tasks. The objective for the master is to select which file to send to which slave, and in which order, so as to minimize the total execution time. The contribution of this paper is twofold. On the theoretical side, we establish complexity results that assess the difficulty of the problem. On the practical side, we design several new heuristics, which are shown to perform as efficiently as the best heuristics in [H. Casanova, A. Legrand, D. Zagorodnov, F. Berman, Heuristics for scheduling parameter sweep applications in Grid environments, in: Ninth Heterogeneous Computing Workshop, IEEE Computer Society Press, Silver Spring, MD, 2000, pp. 349-363; H. Casanova, A. Legrand, D. Zagorodnov, F. Berman, Using simulation to evaluate scheduling heuristics for a class of applications in Grid environments, Research Report RR-1999-46, LIP, ENS Lyon, France, 1999] although their cost is an order of magnitude lower. Author Affiliation: (a) ICPS/LSIIT, UMR CNRS-ULP 7005, Parc d'Innovation, Bd Sebastien Brant, BP 10413, 67412 Illkirch Cedex, France (b) LIP, UMR CNRS-ENS Lyon-INRIA-UCBL 5668, Ecole normale superieure de Lyon, 46 allee d'Italie, 69364 Lyon Cedex 07, France Article History: Received 30 June 2004; Accepted 20 October 2004

Le rachis du sujet âgé se caractérise par des phénomènes dégénératifs associant arthrose, discopathie, vieillissement musculaire et ligamentaire qui touchent près de 80 % des personnes âgées de plus de 70 ans, dont la corrélation avec la clinique n'est pas toujours évidente. Ces lésions peuvent entraîner un rétrécissement du canal rachidien ou des foramens, ou une instabilité locale (listhesis, dislocation rotatoire) ou globale (scoliose ou cyphose dégénérative), source d'un enraidissement et de douleurs parfois importantes. La prise en charge, limitée par les comorbidités et la fragilité de ces patients, repose avant tout sur l'association antalgique, rééducation et corset. Une infiltration peut être envisagée s'il existe une concordance radio-clinique. Dans les cas réfractaires, la chirurgie peut être discutée et doit être la plus minimaliste possible. Quelques pathologies rachidiennes ont été détaillées : le canal lombaire rétréci, la myélopathie cervico-arthrosique, la cyphose dégénérative, la scoliose dégénérative et la camptocormie. The spine of older people is characterized by degenerative changes found in almost 80% of people aged 70 years and over, including osteoarthritis, disc diseases, paraspinal muscles and ligaments changes. The correlation between degenerative changes and clinical symptoms is not clear. However, they can cause spinal and/or foraminal stenoses, local instability (listhesis) or global imbalance (degenerative scoliosis and kyphosis), that can induce pain and functional impairment. The management is limited by the comorbidities and the fragility of the elders. The first line treatment is conservative, and includes painkillers, rehabilitation and brace. Spinal steroid injections can be proposed if there is a good agreement between clinical symptoms and radiographic findings. If the conservative treatment fails, minimally invasive surgery could be performed. Here the following spinal diseases are detailed: lumbar spinal stenosis, degenerative cervical myelopathy, degenerative kyphosis, degenerative scoliosis and camptocormia. [ABSTRACT FROM AUTHOR]

There is a great clinical and genetic heterogeneity in congenital myopathies. Myo-MRI with pattern recognition has become a first-line complementary tool in clinical practice for this group of diseases. For diagnostic purposes, whole-body imaging techniques are preferred when involvement is axial or diffuse, as in most congenital myopathies, because of involvement of the tongue, masticator, neck or trunk muscles. Myo-MRI is widely used to identify abnormalities in muscle signal, volume or texture. Recognizable profiles or patterns have been identified in many of these genetic myopathies. The role of the radiologist is crucial in order to adapt the Myo-MRI protocols to the age of the patient and several clinical situations. Myo-MRI in children with congenital myopathies is a very demanding technique with a balance between acceptable time of examination and sufficient spatial resolution in order to detect subtle changes. Technical evolutions combining qualitative and quantitative analysis are useful to follow disease progression overtime. Outcome measures are expected to play a role in natural history description as well as in future therapeutic trials. Genetic diagnosis and interpretation of next generation sequencing results could be greatly influenced by statistical analysis with tools such as algorithms as well as graphical representations using heatmaps. [ABSTRACT FROM AUTHOR]

Résumé Les complications neurologiques touchant les patients atteints de la maladie de Scheuermann sont rares mais graves. Nous présentons trois cas de patients atteints de maladie de Scheuermann, avec des déficits neurologiques sévères, dus à une ischémie médullaire causée par la compression d’une artère radiculomédullaire par une hernie discale thoracique (deux cas) et une hernie discale lombaire (un cas). Aucun traitement chirurgical n’a été réalisé en raison de l’absence de compression médullaire directe et du caractère irréversible de l’ischémie médullaire. Ces jeunes patients gardent des séquelles neurologiques sévères. Une prise en charge plus précoce aurait pu prévenir ces déficits neurologiques définitifs. Une IRM médullaire avec séquence de diffusion et ADC (coefficient apparent de diffusion) devrait être réalisée en urgence devant le moindre signe de souffrance médullaire. [ABSTRACT FROM AUTHOR]

Background: Neurological complications in Scheuermann's disease are rare but serious.Case Reports: We report three cases of severe neurological deficit due to medullar ischemia attributable to the compression of a radiculomedullar artery by thoracic (two cases) and lumbar (one case) disc herniations associated with Scheuermann's disease. They were not treated surgically because of the absence of direct spinal cord compression or definitive spinal cord ischemia. Those young patients still have severe neurological damage. An earlier management could have prevented them.Conclusion: When doubting about any compressive sign, MRI should be performed with diffusion weighted imaging (DWI) and apparent diffusion coefficient (ADC) sequences in emergency. [ABSTRACT FROM AUTHOR]

Pebble bed reactors, either gas-cooled or fluoride-cooled, are among the most promising advanced reactor concepts with active development worldwide. The relatively small size of the pebbles and the fact that they are continuously recirculated makes the task of simulating fuel burnup particularly challenging. Most solutions proposed thus far suggest dividing the core into spectral zones within which fuel composition is assumed uniform, ignoring differences between the different pebbles in the zone. This work suggests that it is possible with current computing tools and with relatively modest computing resources to perform depletion of pebble bed reactors by depleting each pebble individually. The feasibility of this approach, named hyper-fidelity depletion, is demonstrated using a simplified model that assumes static pebbles in a regular lattice and employing the Monte Carlo code Serpent 2 that provides multiple features suitable for hyper-fidelity depletion, among which the most important is domain decomposition. The obtained results show that the spectral zone methods compared to hyper-fidelity can predict average trends, but are not adequate to determine distribution for quantities of interest such as burnup, fission products, etc. [ABSTRACT FROM AUTHOR]

In this paper, we revisit the well-studied problem of replica placement in tree networks. Rather than minimizing the number of servers needed to serve all client requests, we aim at minimizing the total power consumed by these servers. In addition, we use the most general (and powerful) server assignment policy, where the requests of a client can be served by multiple servers located in the (unique) path from this client to the root of the tree. We consider multi-modal servers that can operate at a set of discrete speeds, using the dynamic voltage and frequency scaling (DVFS) technique. The optimization problem is to determine an optimal location of the servers in the tree, as well as the speed at which each server is operated. A major result is the NP-completeness of this problem, to be contrasted with the minimization of the number of servers, which has polynomial complexity. Another important contribution is the formulation of a Mixed Integer Linear Program (MILP) for the problem, together with the design of several polynomial-time heuristics. We assess the efficiency of these heuristics by simulation. For mid-size instances (up to 30 nodes in the tree), we evaluate their absolute performance by comparison with the optimal solution (obtained via the MILP). The most efficient heuristics provide satisfactory results, within 20% of the optimal solution. [ABSTRACT FROM AUTHOR]

Spondyloarthritis refers to a group of chronic inflammatory rheumatic diseases that predominantly affects the axial skeleton, causing pain and stiffness. Human bone is highly dynamic organ that interacts with a wide array cells and tissues. Process of bone remodelling relies on a delicate balance between bone formation and bone resorption, orchestrated by osteoblasts and osteoclasts. Disruption of this homeostatic balance of bone removal and replacement can manifest as inappropriate new bone formation found in spondylarthritis. We hypothesize that VEGF may promote bone remodelling, stimulate angiogenesis, and both osteoclastic and osteoblastic activity. Anti VEGF may be tested as a dedicated therapy to prevent bone remodelling in spondyloarthritis patients, namely in cases of aggressive disease. Bone remodelling could be monitored by using [18F]Fluoride PET scan. [ABSTRACT FROM AUTHOR]

• Biallelic mutations in TNXB can be a cause of myopathy. • Muscular weakness associates with articular and connective tissue alterations. • Tenascin X reduction in serum and skeletal muscle is present. Tenascin-X, is an extracellular matrix glycoprotein expressed in skin, muscle, tendons, and blood vessels with an anti-adhesive function. Biallelic Tenascin-X mutations cause classical-like Ehlers-Danlos syndrome. We report a 46-year-old woman with slowly progressive weakness of the lower limbs and myalgia from age 28 years. In the past she had Raynaud's phenomenon, multiple sprains and joint dislocations, conjunctival haemorrhages and a colonic perforation during colonoscopy. Neurologic examination showed moderate asymmetric proximal and axial muscular weakness, distal amyotrophy of 4 limbs, moderate skin hyperextensibility, and hypermobility of distal joints of fingers. Whole body Magnetic Resonance Imaging showed symmetric fatty infiltration of thigh and leg muscles, with predominant atrophy of thighs. Next Generation Sequencing revealed two pathogenic TNXB variants, g.32024681C> G , c.7826–1G> C , and g.32016181dup, c.9998dupA, p.(Asn3333Lysfs*35). Western Blot and immunofluorescence studies confirmed a marked Tenascin-X reduction in both patient's serum and muscle. Here we further detail the clinical and genetic spectrum of a patient with classical-like Ehlers-Danlos syndrome and prominent muscle involvement. [ABSTRACT FROM AUTHOR]

• X-linked EDMD may present with camptocormia and minimal contractures. • Muscle biopsy with immunohistochemistry is pivotal in atypical myopathies. • Whole body MRI will allow to recognize new cases. Emery–Dreifuss muscular dystrophy is an early-onset, slowly progressive myopathy characterized by the development of multiple contractures, muscle weakness and cardiac dysfunction. We present here the case of a 65-year-old male patient with a 20 year history of slowly progressive camptocormia, bradycardia and shortness of breath. Examination showed severe spine extensor and neck flexor muscle weakness with slight upper limb proximal weakness. Cardiologic assessment revealed slow atrial fibrillation. Whole body MRI demonstrated adipose substitution of the paravertebral, limb girdle and peroneal muscles as well as the tongue. Emerin immunohistochemistry on patient muscle biopsy revealed the absence of nuclear envelope labeling confirmed by Western Blot. Genetic analysis showed a hemizygous duplication of 5 bases in exon 6 of the EMD, emerin, gene on the X chromosome. This is an unusual presentation of X-linked Emery–Dreifuss muscular dystrophy with adult onset, predominant axial muscles involvement and minimal joint contractures. Diagnosis was prompted by the analysis of emerin on muscle biopsy. [ABSTRACT FROM AUTHOR]

Abstract: This article reviews briefly three important aspects of tonometry: physics, physiology, and glaucoma. With respect to the physical principles of tonometry, deformation of the globe is a key component: force tonometers measure intraocular pressure (IOP) by deforming the globe whereas pressure tonometers do not. Pressure tonometers can provide measurements that are closer to absolute pressure than force tonometers. Tonometry is a physiological measurement that evaluates IOP over time by assessing pulsation in consideration of the pressure gradient from the cornea to the optic nerve. It seems that the outflow characteristics of the trabecular meshwork also modify the pulse amplitude. When diagnosing glaucoma, tonometry alone does not adequately discriminate between normal and diseased eyes. A long-term measurement may be desirable but this, in turn, evokes new problems. Finally, lowering the IOP improves the blood flow in the optic nerve head. [Copyright &y& Elsevier]