Home About us Contact
|
Home About us Contact | ||
|
|
||
Only Used (only + used)
Selected Abstracts369 Tflop/s molecular dynamics simulations on the petaflop hybrid supercomputer ,Roadrunner'CONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 17 2009Timothy C. Germann Abstract We describe the implementation of a short-range parallel molecular dynamics (MD) code, SPaSM, on the heterogeneous general-purpose Roadrunner supercomputer. Each Roadrunner ,TriBlade' compute node consists of two AMD Opteron dual-core microprocessors and four IBM PowerXCell 8i enhanced Cell microprocessors (each consisting of one PPU and eight SPU cores), so that there are four MPI ranks per node, each with one Opteron and one Cell. We will briefly describe the Roadrunner architecture and some of the initial hybrid programming approaches that have been taken, focusing on the SPaSM application as a case study. An initial ,evolutionary' port, in which the existing legacy code runs with minor modifications on the Opterons and the Cells are only used to compute interatomic forces, achieves roughly a 2× speedup over the unaccelerated code. On the other hand, our ,revolutionary' implementation adopts a Cell-centric view, with data structures optimized for, and living on, the Cells. The Opterons are mainly used to direct inter-rank communication and perform I/O-heavy periodic analysis, visualization, and checkpointing tasks. The performance measured for our initial implementation of a standard Lennard,Jones pair potential benchmark reached a peak of 369 Tflop/s double-precision floating-point performance on the full Roadrunner system (27.7% of peak), nearly 10× faster than the unaccelerated (Opteron-only) version. Copyright © 2009 John Wiley & Sons, Ltd. [source] Rumination in posttraumatic stress disorderDEPRESSION AND ANXIETY, Issue 5 2007Tanja Michael Ph.D. Abstract Recent studies have shown that rumination is a powerful predictor of persistent posttraumatic stress disorder (PTSD). However, to date, the mechanisms by which rumination maintains PTSD symptoms are little understood. Two studies of assault survivors, a cross-sectional (N = 81) and a 6-month prospective longitudinal study (N = 73), examined several facets of ruminative thinking to establish which aspects of rumination provide the link to PTSD. The current investigation showed that rumination is not only used as a strategy to cope with intrusive memories but it also triggers such memories. Certain characteristics of rumination, such as compulsion to continue ruminating, occurrence of unproductive thoughts, and "why" and "what if" type questions, as well as negative emotions before and after rumination, were significantly associated with PTSD, concurrently and prospectively. These characteristics explained significantly more variance in PTSD severity than the mere presence of rumination, thereby indicating that not all ways of ruminative thinking are equally maladaptive. Depression and Anxiety 24:307,317, 2007. © 2006 Wiley-Liss, Inc. [source] Forage collection, substrate preparation, and diet composition in fungus-growing antsECOLOGICAL ENTOMOLOGY, Issue 3 2010HENRIK H. DE FINE LICHT 1. Variation and control of nutritional input is an important selective force in the evolution of mutualistic interactions and may significantly affect coevolutionary modifications in partner species. 2. The attine fungus-growing ants are a tribe of more than 230 described species (12 genera) that use a variety of different substrates to manure the symbiotic fungus they cultivate inside the nest. Common ,wisdom' is that the conspicuous leaf-cutting ants primarily use freshly cut plant material, whereas most of the other attine species use dry and partly degraded plant material such as leaf litter and caterpillar frass, but systematic comparative studies of actual resource acquisition across the attine ants have not been done. 3. Here we review 179 literature records of diet composition across the extant genera of fungus-growing ants. The records confirm the dependence of leaf-cutting ants on fresh vegetation but find that flowers, dry plant debris, seeds (husks), and insect frass are used by all genera, whereas other substrates such as nectar and insect carcasses are only used by some. 4. Diet composition was significantly correlated with ant substrate preparation behaviours before adding forage to the fungus garden, indicating that diet composition and farming practices have co-evolved. Neither diet nor preparation behaviours changed when a clade within the paleoattine genus Apterostigma shifted from rearing leucocoprinous fungi to cultivating pterulaceous fungi, but the evolutionary derived transition to yeast growing in the Cyphomyrmex rimosus group, which relies almost exclusively on nectar and insect frass, was associated with specific changes in diet composition. 5. The co-evolutionary transitions in diet composition across the genera of attine ants indicate that fungus-farming insect societies have the possibility to obtain more optimal fungal crops via artificial selection, analogous to documented practice in human subsistence farming. [source] Fabrication of a Sensitive Cholesterol Biosensor Based on Cobalt-oxide Nanostructures Electrodeposited onto Glassy Carbon ElectrodeELECTROANALYSIS, Issue 24 2009Abdollah Salimi Abstract Electrodeposited cobalt oxide (CoOx) nanomaterials are not only used for immobilization of cholesterol oxidase (ChOx) but also as electron transfer mediator for oxidation of H2O2 generated in the enzymatic reaction. Voltammetry and flow injection analysis (FIA) were used for determination of cholesterol. FIA determination of cholesterol with biosensors yielded a calibration curve with the following characteristics: linear range up to 50,,M, sensitivity of 43.5,nA ,M,1 cm,2 and detection limit of 4.2,,M. The apparent Michaelis-Menten constant and the response time of the biosensor are 0.49,mM and 15,s, respectively. This biosensor also exhibits good stability, reproducibility and long life time. [source] What is Sium frigidumHand.-Mazz. (Umbelliferae)?FEDDES REPERTORIUM, Issue 5-6 2003M. G. Pimenov Professor Dr. A rare and enigmatic Chinese species, known as Apium ventricosumH. Boissieu and Sium frigidumHand.-Mazz. (the latter name is only used in current floristic literature), has been shown to be closer related to SinocarumH. Wolff ex Shan RenHwa & PuFaTing. This affinity, indicated recently by ITS sequence investigation, was confirmed by morphological analysis. Attribution of the species to Apium, Sium, or Chamaesium, was not confirmed by molecular and morphological data either. A new combination, Sinocarum ventricosum (H. Boissieu) Pimenov & Kljuykov, has been proposed. The isolated position of S. ventricosum within the genus Sinocarum is emphazised by separation of a new monotypic section, Sinocarum sect. ApiopsisPimenov & Kljuykov. Was ist Sium frigidumHand.-Mazz. (Umbelliferae)? Eine seltene und rätselhafte chinesische Art, bekannt als Apium ventricosumH. Boissieu und Sium frigidumHand.-Mazz. (letzterer Name wird in der aktuellen floristischen Literatur allein benutzt), scheint näher verwandt zu sein mit SinocarumH. Wolff ex Shan RenHwa & Pu FaTing. Diese neuerlich durch IST-Sequenzanalyse festgestellte Affinität wurde durch molekulare und morphologische Daten bestätigt. Der Einschluss der Art in die Gattungen Apium, Sium oder Chamaesium konnte nicht durch molekulare und morphologische Merkmale bestätigt werden. Es wird eine Neukombination: Sinocarum ventricosum (H. Boissieu) Pimenov & Kljuykov vorgeschlagen. Die isolierte Stellung von S. ventricosum innerhalb der Gattung Sinocarum wird durch die Aufstellung einer monotypischen Sektion, Sinocarum sect. ApiopsisPimenov & Kljuykov unterstrichen. [source] Quality counts: new parameters in blood cell countingINTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 3 2009C. BRIGGS Summary Recently several parameters have been introduced to the complete blood count such as nucleated red blood cells, immature granulocytes; immature reticulocyte fraction, immature platelet fraction and red cell fragments as well as new parameters for detection of functional iron deficiency. Leucocyte positional parameters, which may diagnose specific diseases (e.g. differentiate between abnormal lymphocytes in leukaemia and viral conditions and may also detect malarial infection) are now available. At this time they are only used for research; however, generally such parameters later become reportable. One manufacturer's routine analyser allows measurement of cells by flow cytometry using monoclonal antibodies. Currently, there are no accredited external quality assessment schemes (EQAS) for these parameters. For a number of parameters, on some instruments, there is no internal quality control, which brings into question whether these parameters should be used for clinical decision making. Other more established parameters, such as mean platelet volume, red cell distribution width and the erythrocyte sedimentation rate do not have EQAS available. The UK National EQAS for General Haematology held a workshop earlier this year in 2008 to discuss these parameters. Participants were asked to provide a consensus opinion on which parameters are the most important for inclusion in future haematology EQAS. [source] Structure and mechanical properties of cellulose derivatives/soy protein isolate blendsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2008Ziyan Zhou Abstract Biodegradable and biocompatible composites based on soy protein isolate (SPI) and various cellulose derivatives have been prepared, and the dependence of structures and mechanical properties on the content and species of cellulose derivatives for the composites were investigated by X-ray diffraction, differential scanning calorimetry, scanning electron microscope, and tensile test. The selected cellulose derivatives, such as methyl cellulose (MC), hydroxyethyl cellulose (HEC), and hydroxypropyl cellulose, were miscible with SPI when the content of cellulose derivatives was low, and then the isolated crystalline domains, shown as the structures of network and great aggregate, formed with an increase of cellulose derivative content. The miscible blends could produce the higher strength, and even result in the simultaneous enhancement of strength and elongation for the HEC/SPI and MC/SPI blends. Meanwhile, the moderate content of great MC domains also reinforced the materials. However, the damage of original ordered structure in SPI gave the decreased modulus. Since all the components, i.e., cellulose derivatives and soy protein, are biocompatible, the resultant composites are not only used as environment-friendly material, but the biomedical application can be expected, especially for the tissue engineering scaffold. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Capillary electrochromatographic chiral separations with potential for pharmaceutical analysisJOURNAL OF SEPARATION SCIENCE, JSS, Issue 8 2005Debby Mangelings Abstract The use of capillary electrochromatography as a chiral separation technique for pharmaceutical applications is reviewed. Publications of the past 10 years that provide a potential practical application in pharmaceutical analysis are considered. Method development or validation, separation strategies, and potential routine analysis by the methods/applications cited are the main subjects on which we focused our attention. The indirect chiral separation method was only used once in CEC mode. In the direct chiral separations, the use of chiral stationary phases was obviously preferred over the use of chiral mobile phases with non-chiral stationary phases. Amongst the chiral stationary phases, those based on macrocyclic antibiotics and polysaccharide selectors were the most frequently used. Monolithic stationary phases also have several applications, but not so extended as those with packed capillary electrochromatography. The considered papers not only describe the applicability of the technique for relatively large sets of chiral analytes, they also showed that various types of stationary phases can be produced in-house in a simple manner. However, to survive as a mature separation technique, considerable time and effort are still needed to solve some disadvantages currently characterizing capillary electrochromatography. [source] Measuring and reporting on quality in health care: A framework and road map for improving careJOURNAL OF SURGICAL ONCOLOGY, Issue 8 2009Susan E. Brien PhD Abstract Quality of care measurement and reporting at the provider, hospital, or health system level has become increasingly common in health systems around the world. Health system performance reports, whether they be confidentially distributed to the provider or made available to the public, are not only used as a stimulus for quality improvement, but can also be used to inform policy, apportion funding, or in rare cases, punish poorly performing providers. In this review, we outline several principles of quality of healthcare measurement and performance reporting, and describe a framework for optimal performance reporting that provides the greatest opportunity for the desired outcome,health system improvement. The quality reporting framework and roadmap that we present invokes opportunities for improving care in the domain of surgical oncology. J. Surg. Oncol. 2009;99:462,466. © 2009 Wiley-Liss, Inc. [source] A discussion on the performance of impedance matched antenna system and considerations for a better performanceMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 2 2008Adnan Kaya Abstract Impedance matching networks are used extensively in radio communications. In this study, ,-matching circuit has been used as a matching network. The return loss level of several impedance matched microstrip antennas are compared as a function of matching techniques. The ,-matching device is used to construct the antenna tuning units, which is only used to match the front module and the antenna. This circuit impedance region has been investigated analytically under the variable load condition. When the mismatch is occurred, the result is an increase in the energy consumption or transmission quality deterioration. In addition, the input module in antenna system could be damaged if reflection of the signal levels is excessively high. This is interesting application because antennas cannot be considered alone as component with changing electromagnetic properties. The rectangular microstrip antenna was designed at 2.5 GHz frequency by using microstrip feed line. Better return loss level which is ,16.86 dB has been obtained for this antenna using ,-matching circuit. It is shown that theoretical, simulation, and laboratory results are good agreement. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 410,415, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23101 [source] Fatigue rating scales critique and recommendations by the Movement Disorders Society task force on rating scales for Parkinson's disease,MOVEMENT DISORDERS, Issue 7 2010Joseph H. Friedman MD Abstract Fatigue has been shown to be a consistent and common problem in Parkinson's disease (PD) in multiple countries and cultures. It is one of the most disabling of all symptoms, including motor dysfunction, and appears early, often predating the onset of motor symptoms. Several studies of the epidemiology of fatigue have been published, often using different scales, but few on treatment. The Movement Disorder Society (MDS) commissioned a task force to assess available clinical rating scales, critique their psychometric properties, summarize their clinical properties, and evaluate the evidence in support of their use in clinical studies in PD. Six clinical researchers reviewed all studies published in peer reviewed journals of fatigue in PD, evaluated the scales' previous use, performance parameters, and quality of validation data, if available. Scales were rated according to criteria provided by the MDS. A scale was "recommended" if it has been used in clinical studies beyond the group that developed it, has been used in PD and psychometric studies have established that it is a valid, reliable and sensitive to change in people with PD. Requiring a scale to have demonstrated sensitivity to change in PD specifically rather than in other areas in order to attain a rating of "recommended" differs from the use of this term in previous MDS task force scale reviews. "Suggested" scales failed to meet all the criteria of a "recommended" scale, usually the criterion of sensitivity to change in a study of PD. Scales were "listed" if they had been used in PD studies but had little or no psychometric data to assess. Some scales could be used both to screen for fatigue as well as to assess fatigue severity, but some were only used to assess severity. The Fatigue Severity Scale was "recommended" for both screening and severity rating. The Fatigue Assessment Inventory, an expanded version of the Fatigue severity Scale, is "suggested" for both screening and severity. The Functional Assessment of Chronic Illness Therapy-Fatigue was "recommended" for screening and "suggested" for severity. The Multidimensional Fatigue Inventory was "suggested" for screening and "recommended" for severity. The Parkinson Fatigue Scale was "recommended" for screening and "suggested" for severity rating. The Fatigue Severity Inventory was "listed" for both screening and severity. The Fatigue Impact Scale for Daily Use, an adaptation of the Fatigue Impact Scale was "listed" for screening and "suggested" for severity. Visual Analogue and Global Impression Scales are both "listed" for screening and severity. The committee concluded that current scales are adequate for fatigue studies in PD but that studies on sensitivity and specificity of the scales are still needed. © 2010 Movement Disorder Society [source] Modular solvers for image restoration problems using the discrepancy principleNUMERICAL LINEAR ALGEBRA WITH APPLICATIONS, Issue 5 2002Peter Blomgren Abstract Many problems in image restoration can be formulated as either an unconstrained non-linear minimization problem, usually with a Tikhonov -like regularization, where the regularization parameter has to be determined; or as a fully constrained problem, where an estimate of the noise level, either the variance or the signal-to-noise ratio, is available. The formulations are mathematically equivalent. However, in practice, it is much easier to develop algorithms for the unconstrained problem, and not always obvious how to adapt such methods to solve the corresponding constrained problem. In this paper, we present a new method which can make use of any existing convergent method for the unconstrained problem to solve the constrained one. The new method is based on a Newton iteration applied to an extended system of non-linear equations, which couples the constraint and the regularized problem, but it does not require knowledge of the Jacobian of the irregularity functional. The existing solver is only used as a black box solver, which for a fixed regularization parameter returns an improved solution to the unconstrained minimization problem given an initial guess. The new modular solver enables us to easily solve the constrained image restoration problem; the solver automatically identifies the regularization parameter, during the iterative solution process. We present some numerical results. The results indicate that even in the worst case the constrained solver requires only about twice as much work as the unconstrained one, and in some instances the constrained solver can be even faster. Copyright © 2002 John Wiley & Sons, Ltd. [source] Sheathless Implantation of Permanent Coronary Sinus-LV Pacing LeadsPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2 2006PETER HOFFMEISTER Background: Implantation of CS-LV pacing leads is usually accomplished through specialized sheaths with additional use of contrast venography and other steps. Direct implantation at a target pacing site could provide a simplified procedure with appropriate leads. Methods: A progressive CS-LV lead implant protocol was used, with initial attempts made to place the lead directly using only fluoroscopy and lead stylet or wire manipulation. Coronary sinus (CS) sheaths were only used later if direct lead placement failed. Results: There were 105 attempted implants with 96% (101/105) success. Leads were implanted sheathlessly in 69% (70/101) cases. Pacing parameters and final lead position did not differ significantly between implants that did or did not require sheaths for implants. Three peri-procedural complications occurred in implants where sheaths were used. In 33% (33/101) of implants, the leads were placed without the use of sheaths or contrast venography in 20 minutes or less. Conclusions: Direct placement of the CS-LV pacing lead without sheaths can be accomplished successfully in a majority of implants and in ,20 minutes in a third, without inferior pacing parameters. This may provide for shorter or less technically difficult or expensive procedures with low risk. [source] Guidelines for the Management of Tinea Capitis in ChildrenPEDIATRIC DERMATOLOGY, Issue 3 2010Talia Kakourou M.D. Tinea capitis always requires systemic treatment because topical antifungal agents do not penetrate the hair follicle. Topical treatment is only used as adjuvant therapy to systemic antifungals. The newer oral antifungal agents including terbinafine, itraconazole, and fluconazole appear to have efficacy rates and potential adverse effects similar to those of griseofulvin in children with TC caused by Trichophyton species, while requiring a much shorter duration of treatment. They may be, however, more expensive (Grading of recommendation A; strength of evidence 1a). Griseofulvin is still the treatment of choice for cases caused by Microsporum species. Its efficacy is superior to that of terbinafine (Grading of recommendation A; strength of evidence 1b), and although its efficacy and treatment duration is matched by fluconazole (Grading of recommendation A; strength of evidence 1b) and itraconazole (Grading of recommendation A; strength of evidence 1b), griseofulvin is cheaper. It must be noted, however, that griseofulvin is nowadays not available in certain European countries (e.g., Belgium, Greece, Portugal, and Turkey). [source] Development of a FTA versus Parts Count Method Model: Comparative FTAQUALITY AND RELIABILITY ENGINEERING INTERNATIONAL, Issue 5 2003G. Arcidiacono Abstract This study adopts a special Fault Tree Analysis (FTA) method called Comparative FTA to compare the reliability of an electronic braking system with its mechanical counterpart. To this end two Top Events, ,Ineffective parking braking' and ,Wheels jamming during emergency braking', were analysed. One of the limitations of classic FTA is that the setting up of the tree diagram requires the long-term involvement,one to two months according to Fiat Auto,of specialists of the system being studied. For this reason, therefore, when dealing with relatively complex systems, classic FTA is only used when safety is involved. This paper introduces a simplified FTA model based on the same principle as the Parts Count Method, which limits its attention to the new branches, thereby avoiding the study of all the branches of the tree, in order to make FTA management easier and to encourage its use. The probability that a Top Event takes place is therefore evaluated by studying the different causes which diversify the solutions considered. This approach is a lean practice to minimize the resources and the time of the analysis. It has guaranteed very satisfactory results and, therefore, Fiat Auto has introduced the practice in their Corporate Instructions. Copyright © 2003 John Wiley & Sons, Ltd. [source] DARK AND SHINY: THE DISCOVERY OF CHROMITE IN BRONZE AGE FAIENCE*ARCHAEOMETRY, Issue 2 2006N. C. F. GROOT The Late Bronze Age (1550,1200 bc) in the Near East was a period of cultural development, international trade and technological innovation, notably in metallurgy and silicate technology. As a spin-off of the new glass technology, new colorants were also applied to faience glazes presumably to increase their aesthetic value. Here, we report on the presence of chromite minerals in the glaze of a faience vessel from Deir ,Alla, Jordan, 1200 years earlier than reported so far. Importantly, chromite was not only used as a greyish pigment, but also as a nucleating agent for spherulitic crystallization of augite in the amorphous glaze. These synthetic augite formations give a unique, sparkly appearance to the faience vessel, apparently imitating a metallic look. The making of such an intricate glaze and its contemporary significance reflect not only the high level but also the appreciation of innovation in that region at that time. [source] Adverse health effects related to tobacco smoke exposure in a cohort of three-year oldsACTA PAEDIATRICA, Issue 3 2008AnnaKarin Johansson Abstract Aim: To analyse the importance of mothers' smoking during pregnancy and/or environmental tobacco smoke (ETS) exposure in early childhood for children's health and well-being at the age of 3 years. Methods: Four groups from a population based cohort (n = 8850) were compared: children with nonsmoking mother during pregnancy and nonsmoking parents at the age of 3 years (n = 7091); children with only foetal exposure (n = 149); children exposed only postnatally (n = 895) and children exposed both pre- and postnatally (n = 595). Odds ratios and 95% confidence intervals were calculated. Results: Children exposed both pre- and postnatally had more wheezing (1.14; 1.07,1.21) and rhinitis (1.16; 1.06,1.26), used more cough-mixture (1.07; 1.01,1.14) and broncodilatating drugs (1.08; 1.02,1.15) and suffered more from excessive crying (1.31; 1.13,1.51) and irritability (1.27; 1.09,1.48) compared to children with nonsmoking parents. Children exposed only postnatally had more rhinitis (1.24; 1.12,1.37), used more cough-mixture (1.14; 1.05,1.29) and suffered more from poor sleep (1.26; 1.07,1.47) than children of nonsmoking parents. Children with prenatal exposure only used more broncodilatating drugs (1.45; 1.03,2.04) and suffered more from poor sleep (2.06; 1.09,3.87). Conclusion: Health differences, small but significant, indicate that prenatal and/or postnatal ETS exposure alone, or in combination, seems to interfere with child health, supporting the importance of zero tolerance. However, as most smoking parents in Sweden try to protect their children from ETS exposure, the results also might indicate that protective measures are worthwhile. [source] | |||||||||||||||||||