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Sequential
Terms modified by Sequential Selected AbstractsSequential 1,3-Dipolar Cycloaddition of Nitrones to ,-(2-Aminophenyl) ,,,-Ynones and Cyclocondensation: A New Entry to the Isoxazolino[4,5- c]quinoline RingEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 7 2009Giorgio Abbiati Abstract The reaction of ,-(2-aminophenyl) ,,,-ynones with N -methyl nitrones provides a simple and efficient entry to the isoxazolino[4,5- c]quinoline ring system through a sequential 1,3-dipolar cycloaddition/annulation process. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Canal shapes produced sequentially during instrumentation with Quantec SC rotary nickel,titanium instruments: a study in simulated canalsINTERNATIONAL ENDODONTIC JOURNAL, Issue 2 2001I. T. Griffiths Abstract Aim The aim of this study was to determine the shaping ability of Quantec SC nickel,titanium rotary instruments in simulated root canals. Methodology Forty simulated canals consisting of four different shapes in terms of angle and position of curvature were prepared with Quantec SC instruments. Sequential still images were taken of the canals using a video camera attached to a computer with image analysis software. Images were taken preoperatively, and then after instrument 7 (Size 25, 0.05 taper), instrument 8 (size 25, 0.06 taper), and instrument 10 (size 45, 0.02 taper) were taken to length. Each sequential postoperative image was superimposed individually over the preoperative image in order to highlight the amount and position of material removed during preparation. Results Overall, the mean preparation time to size 10 was 3.6 min with 12 mm canals taking on average less time than 8 mm canals. There was a highly significant difference between the canal types (P < 0.0001). No instruments fractured within the canal or deformed, although one instrument separated from the latch grip. All canals remained patent. Following preparation to size 10, 19 canals (48%) retained their length, eight (20%) lost length, and 13 (32%) gained length; the magnitude of the change in length was always 0.5 mm or below. Following preparation to size 7 instruments all canals showed aberrant shapes. Excess removal of material along the outer aspect of the curve between the beginning of the curve and the end-point (outer widening) was found in 26 canals (65%) after instrument 7. At the same stage of preparation six canals (15%) had zips, three (8%) had ledges and five (13%) had perforations. Following preparation to size 10, 27 (68%) canals were perforated. Conclusions Under the conditions of the study, Quantec SC instruments consistently produced aberrations when canals were enlarged to size 7 (size 25, 0.05 taper) or above. Care should be exercised when using these instruments in real teeth. [source] Alternation of Chemoselective Control in Stille,Heck and Heck,Stille Reaction SequencesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4 2009Kye-Simeon Masters Abstract Sequential and one-pot Stille,Heck and Heck,Stille reaction processes have been invoked to give divergent access to polycyclic ring systems. Both reaction conditions and substrate structure are important in determining the nature of the reaction products formed. The Heck,Stille reactions have involved a reversal of the usual Heck regioselectivity and both cine- and ipso- substitutions have been observed in the Stille reaction. [source] On "Angiographic Assessment of Sequential and Individual Coronary Artery Bypass Grafting"JOURNAL OF CARDIAC SURGERY, Issue 6 2003Rick A. Esposito M.D. No abstract is available for this article. [source] Sequential and iterative architectures for distributed model predictive control of nonlinear process systemsAICHE JOURNAL, Issue 8 2010Jinfeng Liu Abstract In this work, we focus on distributed model predictive control of large scale nonlinear process systems in which several distinct sets of manipulated inputs are used to regulate the process. For each set of manipulated inputs, a different model predictive controller is used to compute the control actions, which is able to communicate with the rest of the controllers in making its decisions. Under the assumption that feedback of the state of the process is available to all the distributed controllers at each sampling time and a model of the plant is available, we propose two different distributed model predictive control architectures. In the first architecture, the distributed controllers use a one-directional communication strategy, are evaluated in sequence and each controller is evaluated only once at each sampling time; in the second architecture, the distributed controllers utilize a bi-directional communication strategy, are evaluated in parallel and iterate to improve closed-loop performance. In the design of the distributed model predictive controllers, Lyapunov-based model predictive control techniques are used. To ensure the stability of the closed-loop system, each model predictive controller in both architectures incorporates a stability constraint which is based on a suitable Lyapunov-based controller. We prove that the proposed distributed model predictive control architectures enforce practical stability in the closed-loop system and optimal performance. The theoretical results are illustrated through a catalytic alkylation of benzene process example. © 2010 American Institute of Chemical Engineers AIChE J, 2010 [source] Learning Styles of Interior Design Students as Assessed by the Gregorc Style DelineatorJOURNAL OF INTERIOR DESIGN, Issue 1 2001Stephanie A. Watson Ed.D. The purpose of this study was to determine the preferred learning style of undergraduate students majoring in interior design. The Gregorc Style Delineator, a self-report instrument to determine learning style, was administered to 147 undergraduate interior design students enrolled in Foundation for Interior Design Education Research (FIDER) accredited programs located within the Southwest Region of the United States. To determine the dominant learning style of undergraduate interior design students, frequency distributions were compiled. Overall, the most important finding in this study was the diversity of learning styles among interior design students. Not only were all learning styles represented in the sample, but 49% of students exhibited dominance in more than one style,unlike the results of previous studies with non interior design students. The most common learning styles found among interior design students are a logical and hands-on learning style, known as Concrete Sequential, and a combination of experimental, imaginative, and people-oriented learning styles, known as Concrete Random/Abstract Random. Diversity in student learning styles supports the argument for the need for instructors to have a repertoire of teaching methods. Instructors should be knowledgeable in learning style theory, should know their own learning style, and should be able to teach using a variety of styles. [source] Heterogeneity in antifungal susceptibility of clones of Candida albicans isolated on single and sequential visits from a HIV-infected southern Chinese cohortJOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 6 2001Y. H. Samaranayake Abstract: The increased frequency and severity of candidal infections in human immunodeficiency virus (HIV)-infected individuals has prompted the wide use of antifungals, such as amphotericin B, ketoconazole, and fluconazole, resulting in the emergence of drug-resistant strains of Candida albicans. To study this phenomenon in an ethnic Chinese cohort, we isolated multiple colonies of Candida from the oral cavities of 16 HIV-infected patients on single and subsequent sequential visits over a period of 12 months. Ten of the 16 patients had sporadic episodes of oropharyngeal candidiasis (Group A), while the remainder were asymptomatic with respect to this condition (Group B). Oral rinses were collected and immediately processed in the laboratory for the isolation of C. albicans in a standard manner. A total of 433 C. albicans isolates were tested for their susceptibility to amphotericin B, ketoconazole and fluconazole by an agar diffusion method using the commercially available E-test. All tested isolates demonstrated variable susceptibility to amphotericin B, ketoconazole and fluconazole. The minimum inhibitory concentration (MIC) of the isolates for amphotericin B, ketoconazole and fluconazole ranged from <0.002,1.5 ,g/ml, <0.002,4.0 ,g/ml and <0.016,32 ,g/ml, respectively. Sequential isolates of a few patients demonstrated variable susceptibility to all the antifungals, and no discernible MIC pattern emerged either in group A or B over time. Interestingly, significant variation in antifungal susceptibility was also noted in isolates obtained from the same patient on a single visit. Sequential yeast isolates in 9 of 16 patients (56%) demonstrated significant differences in MIC within and between visits for both amphotericin B and ketoconazole, while a lower percentage , 44% (7/16) , exhibited this trait for fluconazole. Our study demonstrates the diversity in antifungal susceptibility in either commensal or "infective" oral strains of C. albicans in HIV disease, and shows the need for vigilance for the emergence of resistant strains, and for frequent antifungal susceptibility studies. [source] A molecular epidemiological study of sequential oral isolates of Candida albicans from terminally ill patientsJOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 4 2001M. J. Wilson Abstract: The pattern of candidal colonisation was studied in a group of terminally ill patients receiving antifungal treatment for oral candidosis. A total of 43 isolates of C. albicans was collected pre- and post-antifungal treatment from patients up to a maximum period of 4 weeks. Isolates were analysed by electrophoretic karyotyping (EK) and by inter-repeat polymerase chain reaction (IR-PCR). Fifteen electrophoretic karyotypes and 17 IR-PCR profiles were identified. Sequential isolates from 10 patients yielded identical profiles in both EKs and IR-PCR analyses. In the case of four patients, minor differences in the profiles were obtained by either EK or IR-PCR. The findings suggest that antifungal treatment in this patient group fails to eradicate the original C. albicans strain, thereby allowing recolonisation of the oral cavity. The present study has also shown that either EK or IR-PCR is a useful typing approach in such epidemiological investigations. [source] Reversal of multidrug resistance-associated protein-mediated daunorubicin resistance by camptothecinJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 8 2002David Chauvier Abstract The multidrug-resistance (MR) status of camptothecin (CPT) was investigated in colon adenocarcinoma HT29 cells, leukemia K562, and breast carcinoma MCF7 cells expressing P-glycoprotein (Pgp) and/or MR-associated protein (MRP1). The concentration that induced 50% growth inhibition (IC50) against CPT was 0.14 and 0.20 ,M in parental K562/WT and MCF7/WT cells, respectively. The drug resistant subline KH30 and MCF7/VP cells, which both overexpress MRP1, presented IC50 values of 0.63 and 3.10 ,M, respectively. The resulting resistance indexes were 3.80 and 12.50, respectively. However, in KH300 cells, a cell line that preferentially overexpresses Pgp, the IC50 of CPT was 0.08 ,M and thus did not exhibit resistance against CPT. In MCF7/DoX cells, preferentially overexpressing Pgp, but also a significant level of MRP1, the IC50 of CPT was 0.64 ,M and thus presented a resistance index of 3.26 against CPT. The cytotoxic effect of CPT was modulated in cells expressing MRP1 (MCF7/VP, HT29 cells) by the specific MRP1 modulators, probenecid and MK571. These results led us to consider CPT as a substrate for MRP1 and a potential modulator of MRP1 activity. To test this hypothesis, we examined the ability of nontoxic concentrations of CPT to sensitize MRP1-overexpressing cells to daunorubicin (DNR). In MCF7/VP and KH30 cells, nontoxic concentrations of CPT were able to enhance cytotoxicity of DNR and its nuclear accumulation. Sequential and simultaneous associations of CPT (100 nM) and DNR provided complete reversal of resistance, thus showing a synergistic effect in KH30 cells. However, simultaneous association (with 10 or 20 nM CPT) had an additive effect in MCF7/VP. These data suggest that CPT could be proposed as a candidate for the reversal of the MRP1 phenotype at clinically achievable concentrations. © 2002 Wiley-Liss Inc. and the American Pharmaceutical Association J Pharm Sci 91:1765,1775, 2002 [source] Synthesis of star-shaped copolymers with methyl methacrylate and n -butyl methacrylate by metal-catalyzed living radical polymerization: Block and random copolymer arms and microgel cores,JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 5 2002Kyung-Youl Baek Abstract Various star-shaped copolymers of methyl methacrylate (MMA) and n -butyl methacrylate (nBMA) were synthesized in one pot with RuCl2(PPh3)3 -catalyzed living radical polymerization and subsequent polymer linking reactions with divinyl compounds. Sequential living radical polymerization of nBMA and MMA in that order and vice versa, followed by linking reactions of the living block copolymers with appropriate divinyl compounds, afforded star block copolymers consisting of AB- or BA-type block copolymer arms with controlled lengths and comonomer compositions in high yields (,90%). The lengths and compositions of each unit varied with the amount of each monomer feed. Star copolymers with random copolymer arms were prepared by the living radical random copolymerization of MMA and nBMA followed by linking reactions. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 633,641, 2002; DOI 10.1002/pola.10145 [source] Sequential Plasma Lactate Concentrations as Prognostic Indicators in Adult Equine EmergenciesJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 1 2010B.S. Tennent-Brown Background: Sequential lactate concentration ([LAC]) measurements have prognostic value in that hospitalized humans and neonatal foals that have a delayed return to normolactatemia have greater morbidity and case fatality rate. Hypothesis: Prognosis for survival is decreased in horses with a delayed return to normal [LAC]. Animals: Two hundred and fifty adult horses presented for emergency evaluation excepting horses evaluated because of only ophthalmologic conditions, superficial wounds, and septic synovitis without systemic involvement. Methods: Prospective observational study. [LAC] was measured at admission and then at 6, 12, 24, 48, and 72 hours after admission. The change in [LAC] over time ([LAC],T) was calculated from changes in [LAC] between sampling points. Results: Median [LAC] was significantly (P < .001) higher at admission in nonsurvivors (4.10 mmol/L [range, 0.60,18.20 mmol/L]) when compared with survivors (1.30 mmol/L [range, 0.30,13.90 mmol/L]) and this difference remained at all subsequent time points. The odds ratio for nonsurvival increased from 1.29 (95% confidence interval 1.17,1.43) at admission to 49.90 (6.47,384) at 72 hours after admission for every 1 mmol/L increase in [LAC]. [LAC],T was initially positive in all horses but became negative and significantly lower in nonsurvivors for the time periods between 24,72 hours (, 0.47, P= .001) and 48,72 hours (, 0.07, P= .032) when compared with survivors (0.00 at both time periods) consistent with lactate accumulation in nonsurvivors. Conclusions and Clinical Importance: These results indicate that lactate metabolism is impaired in critically ill horses and [LAC],T can be a useful prognostic indicator in horses. [source] Sequential and contingent prenatal screening for Down syndromePRENATAL DIAGNOSIS, Issue 9 2006Nicholas J Wald Abstract Objective To compare the Integrated test in three policies for prenatal Down syndrome screening: Integrated screening for all women, sequential screening (first-trimester tests allowing early completion of screening for high-risk pregnancies), and Contingent screening (early completion of screening for high- and low-risk pregnancies). Design and Methods Estimation of detection rates (DRs) and false-positive rates (FPRs) using Monte Carlo simulation and cost effectiveness for each method. Setting and Population Down syndrome affected and unaffected pregnancies studied in the Serum Urine and Ultrasound Screening Study (SURUSS). Results and Main Outcomes Integrated screening has the best screening performance. The performance of the other two policies approached that of Integrated screening as the first-trimester test FPR decreased. If the first-trimester FPR is set to 0.5% (risk , 1 in 30) with an overall DR of 90%, sequential and contingent screening yield overall FPRs of 2.25% and 2.42%, respectively, and 66% of the affected pregnancies are detected by the first-trimester test. The Integrated test on all women yields an FPR of 2.15%. With sequential screening, 99.5% of women would proceed to an Integrated test, or 30% with contingent screening if those with first-trimester test risks of ,1 in 2000 are classified screen-negative and receive no further testing. About 20% of affected pregnancies identified in the first trimester using sequential or contingent screening would have unnecessary terminations (they would miscarry before the early second trimester). Contingent screening is the most cost-effective if there is no alphafetoprotein screening for neural tube defects, otherwise Integrated screening is more cost-effective. Conclusions Integrated screening for all women is the simplest, most effective, and the safest policy. Contingent screening is the most complex with the lowest screening performance. Making an earlier diagnosis with sequential and contingent screening has adverse consequences that are sufficient to discourage their use. Copyright © 2006 John Wiley & Sons, Ltd. [source] ChemInform Abstract: Enantioselective Synthesis of syn/anti-1,3-Amino Alcohols via Proline-Catalyzed Sequential ,-Aminoxylation/,-Amination and Horner,Wadsworth,Emmons Olefination of Aldehydes.CHEMINFORM, Issue 42 2010Vishwajeet Jha Abstract The target compounds are prepared with anti- or syn-selectivity using D- or L-proline as a catalyst, respectively. [source] ChemInform Abstract: Polysubstituted Quinolines from 2-Alkynylanilines and ,,,-Ynones Through a Sequential Conjugate Addition,Cyclization Process.CHEMINFORM, Issue 40 2009Roberta Bernini Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: N,N-Disubstituted Propargylamines as Tools in the Sequential 1,3-Dipolar Cycloaddition/Arylation Processes to the Formation of Polyheterocyclic Systems.CHEMINFORM, Issue 51 2008Luca Basolo Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Synthesis of Chromans by Sequential "[3 + 3]-Cyclization/Williamson" Reactions of 1,3-Bis(trimethylsilyloxy)-7-chlorohepta-1,3-dienes.CHEMINFORM, Issue 47 2006Van Thi Hong Nguyen Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Rapid Access for the Synthesis of 1-N-Methyl-spiro[2.3,]oxindole-spiro[3.7,,] (3,,-Aryl)-5,,-methyl-3,,,3a,,,4,,,5,,,6,,, 7,,-hexahydro-2H-pyrazolo[4,3-c]pyridine-4-aryl-pyrrolidines Through Sequential 1,3-Dipolar Cycloaddition and Annulation.CHEMINFORM, Issue 23 2006Gowri Sridhar Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Synthesis of 7,8-Benzo-9-aza-4-oxabicyclo[3.3.1]nonan-3-ones by Sequential "Condensation,Iodolactonization" Reactions of 1,1-Bis(trimethylsilyloxy)ketene Acetals with Isoquinolines.CHEMINFORM, Issue 14 2006Ehsan Ullah Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] ChemInform Abstract: A Convenient Method for the Preparation of Unsymmetrical Bis-aldols by Way of Sequential Two Aldol Reactions.CHEMINFORM, Issue 24 2001Hidehiro Arai Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Influence of pH on the Photochemical and Electrochemical Reduction of the Dinuclear Ruthenium Complex, [(phen)2Ru(tatpp)Ru(phen)2]Cl4, in Water: Proton-Coupled Sequential and Concerted Multi-Electron ReductionCHEMISTRY - A EUROPEAN JOURNAL, Issue 15 2005Norma R. de Tacconi Prof. Abstract The dinuclear ruthenium complex [(phen)2Ru(tatpp)Ru(phen)2]4+ (P; in which phen is 1,10-phenanthroline and tatpp is 9,11,20,22-tetraaza tetrapyrido[3,2-a:2,3,-c:3,,,2,,-l:2,,,,3,,,]-pentacene) undergoes a photodriven two-electron reduction in aqueous solution, thus storing light energy as chemical potential within its structure. The mechanism of this reduction is strongly influenced by the pH, in that basic conditions favor a sequential process involving two one-electron reductions and neutral or slightly acidic conditions favor a proton-coupled, bielectronic process. In this complex, the central tatpp ligand is the site of electron storage and protonation of the central aza nitrogen atoms in the reduced products is observed as a function of the solution pH. The reduction mechanism and characterization of the rich array of products were determined by using a combination of cyclic and AC voltammetry along with UV-visible reflectance spectroelectrochemistry experiments. Both the reduction and protonation state of P could be followed as a function of pH and potential. From these data, estimates of the various reduced species' pKa values were obtained and the mechanism to form the doubly reduced, doubly protonated complex, [(phen)2Ru(H2tatpp)Ru(phen)2]4+ (H2P) at low pH (,7) could be shown to be a two-proton, two-electron process. Importantly, H2P is also formed in the photochemical reaction with sacrificial reducing agents, albeit at reduced yields relative to those at higher pH. [source] Safety and Immunogenicity Profile of the Concomitant Administration of ZOSTAVAX and Inactivated Influenza Vaccine in Adults Aged 50 and OlderJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 10 2007Boris Kerzner MD OBJECTIVES: To evaluate the safety and immunogenicity of ZOSTAVAX administered concomitantly with inactivated influenza vaccine or sequentially in adults aged 50 and older. DESIGN: Randomized, blinded, placebo-controlled study. SETTING: Thirteen U.S. and seven European study sites. PARTICIPANTS: Three hundred eighty-two concomitantly, 380 sequentially vaccinated subjects. INTERVENTION: The concomitant vaccination group received influenza vaccine and ZOSTAVAX at separate injection sites on Day 1 and placebo at Week 4. The nonconcomitant vaccination group received influenza vaccine and placebo at separate injection sites on Day 1 and ZOSTAVAX at Week 4. MEASUREMENTS: Primary safety endpoints: vaccine-related serious adverse experiences (AEs) within 28 days postvaccination (PV); and diary card,prompted local and systemic AEs. Primary immunogenicity endpoints: geometric mean titer (GMT) and geometric mean fold rise (GMFR) from baseline of varicella-zoster virus (VZV) antibody (Ab) at 4 weeks PV according to glycoprotein enzyme-linked immunosorbent assay (gpELISA) and GMT of influenza Ab for the three vaccine strains (2005,2006 influenza season) at 4 weeks PV according to hemagglutination inhibition assay. Secondary immunogenicity endpoint: influenza seroconversion rates (SCRs). RESULTS: No serious AEs related to ZOSTAVAX were observed during the study. VZV Ab GMTs 4 weeks PV for the concomitant and sequential groups were 554 and 597 gpELISA U/mL, respectively. The estimated VZV Ab GMT ratio was 0.9 (95% confidence interval (CI)=0.8,1.0), indicating noninferior (P<.001 for the null hypothesis of GMT ratio <0.67) responses. Estimated VZV Ab GMFR from baseline in the concomitant group was 2.1 (95% CI=2.0,2.3), indicating acceptable fold rise. Estimated GMT ratios (concomitant/sequential) for influenza strains A(H1N1), A(H3N2), and B were 0.9 (95% CI=0.8,1.1), 1.1 (95% CI=0.9,1.3), and 0.9 (95% CI=0.8,1.1), respectively, and SCRs were comparable across both groups, with more than 85% achieving titers of 1:40 or greater, meeting regulatory criteria. CONCLUSION: ZOSTAVAX and influenza vaccine given concomitantly are generally well tolerated in adults aged 50 and older. Ab responses were similar whether ZOSTAVAX and influenza vaccine were given concomitantly or sequentially. [source] A comparative study of awareness methods for peer-to-peer distributed virtual environmentsCOMPUTER ANIMATION AND VIRTUAL WORLDS (PREV: JNL OF VISUALISATION & COMPUTER ANIMATION), Issue 5 2008S. Rueda Abstract The increasing popularity of multi-player online games is leading to the widespread use of large-scale Distributed Virtual Environments (DVEs) nowadays. In these systems, peer-to-peer (P2P) architectures have been proposed as an efficient and scalable solution for supporting massively multi-player applications. However, the main challenge for P2P architectures consists of providing each avatar with updated information about which other avatars are its neighbors. This problem is known as the awareness problem. In this paper, we propose a comparative study of the performance provided by those awareness methods that are supposed to fully solve the awareness problem. This study is performed using well-known performance metrics in distributed systems. Moreover, while the evaluations shown in the literature are performed by executing P2P simulations on a single (sequential) computer, this paper evaluates the performance of the considered methods on actually distributed systems. The evaluation results show that only a single method actually provides full awareness to avatars. This method also provides the best performance results. Copyright © 2008 John Wiley & Sons, Ltd. [source] Initialization Strategies in Simulation-Based SFE Eigenvalue AnalysisCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 5 2005Song Du Poor initializations often result in slow convergence, and in certain instances may lead to an incorrect or irrelevant answer. The problem of selecting an appropriate starting vector becomes even more complicated when the structure involved is characterized by properties that are random in nature. Here, a good initialization for one sample could be poor for another sample. Thus, the proper eigenvector initialization for uncertainty analysis involving Monte Carlo simulations is essential for efficient random eigenvalue analysis. Most simulation procedures to date have been sequential in nature, that is, a random vector to describe the structural system is simulated, a FE analysis is conducted, the response quantities are identified by post-processing, and the process is repeated until the standard error in the response of interest is within desired limits. A different approach is to generate all the sample (random) structures prior to performing any FE analysis, sequentially rank order them according to some appropriate measure of distance between the realizations, and perform the FE analyses in similar rank order, using the results from the previous analysis as the initialization for the current analysis. The sample structures may also be ordered into a tree-type data structure, where each node represents a random sample, the traverse of the tree starts from the root of the tree until every node in the tree is visited exactly once. This approach differs from the sequential ordering approach in that it uses the solution of the "closest" node to initialize the iterative solver. The computational efficiencies that result from such orderings (at a modest expense of additional data storage) are demonstrated through a stability analysis of a system with closely spaced buckling loads and the modal analysis of a simply supported beam. [source] HPCTOOLKIT: tools for performance analysis of optimized parallel programs,CONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 6 2010L. Adhianto Abstract HPCTOOLKIT is an integrated suite of tools that supports measurement, analysis, attribution, and presentation of application performance for both sequential and parallel programs. HPCTOOLKIT can pinpoint and quantify scalability bottlenecks in fully optimized parallel programs with a measurement overhead of only a few percent. Recently, new capabilities were added to HPCTOOLKIT for collecting call path profiles for fully optimized codes without any compiler support, pinpointing and quantifying bottlenecks in multithreaded programs, exploring performance information and source code using a new user interface, and displaying hierarchical space,time diagrams based on traces of asynchronous call path samples. This paper provides an overview of HPCTOOLKIT and illustrates its utility for performance analysis of parallel applications. Copyright © 2009 John Wiley & Sons, Ltd. [source] Structural testing criteria for message-passing parallel programsCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 16 2008S. R. S. Souza Abstract Parallel programs present some features such as concurrency, communication and synchronization that make the test a challenging activity. Because of these characteristics, the direct application of traditional testing is not always possible and adequate testing criteria and tools are necessary. In this paper we investigate the challenges of validating message-passing parallel programs and present a set of specific testing criteria. We introduce a family of structural testing criteria based on a test model. The model captures control and data flow of the message-passing programs, by considering their sequential and parallel aspects. The criteria provide a coverage measure that can be used for evaluating the progress of the testing activity and also provide guidelines for the generation of test data. We also describe a tool, called ValiPar, which supports the application of the proposed testing criteria. Currently, ValiPar is configured for parallel virtual machine (PVM) and message-passing interface (MPI). Results of the application of the proposed criteria to MPI programs are also presented and analyzed. Copyright © 2008 John Wiley & Sons, Ltd. [source] JAC: declarative Java concurrencyCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 5 2006Max Haustein Abstract The Java programming language has a low-level concurrency model which is hard to use and does not blend well with inheritance. JAC is an extension of Java that introduces a higher level of concurrency, hiding threads and separating thread synchronization from application logic in a declarative fashion. The emphasis is on limiting the differences between sequential and concurrent code, thus furthering code reuse, and on avoiding inheritance anomalies. This is achieved by taking a middle road between concurrent code on the one hand and complete separation of sequential application logic from concurrency mechanisms on the other. An extensive comparison with related approaches is given for motivating our design decisions. Copyright © 2005 John Wiley & Sons, Ltd. [source] A parallel Broyden approach to the Toeplitz inverse eigenproblemCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 6 2004Jesús Peinado Abstract In this work we show a portable sequential and a portable parallel algorithm for solving the inverse eigenproblem for real symmetric Toeplitz matrices. Both algorithms are based on Broyden's method for solving nonlinear systems. We reduced the computational cost for some problem sizes, and furthermore we managed to reduce spatial cost considerably, compared in both cases with parallel algorithms proposed by other authors and by us, although sometimes quasi-Newton methods (as Broyden) do not reach convergence in all the test cases. We have implemented the parallel algorithm using the parallel numerical linear algebra library SCALAPACK based on the MPI environment. Experimental results have been obtained using two different architectures: a shared memory multiprocessor, the SGI PowerChallenge, and a cluster of Pentium II PCs connected through a myrinet network. The algorithms obtained are scalable in all the cases. Copyright © 2004 John Wiley & Sons, Ltd. [source] User transparency: a fully sequential programming model for efficient data parallel image processingCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 6 2004F. J. Seinstra Abstract Although many image processing applications are ideally suited for parallel implementation, most researchers in imaging do not benefit from high-performance computing on a daily basis. Essentially, this is due to the fact that no parallelization tools exist that truly match the image processing researcher's frame of reference. As it is unrealistic to expect imaging researchers to become experts in parallel computing, tools must be provided to allow them to develop high-performance applications in a highly familiar manner. In an attempt to provide such a tool, we have designed a software architecture that allows transparent (i.e. sequential) implementation of data parallel imaging applications for execution on homogeneous distributed memory MIMD-style multicomputers. This paper presents an extensive overview of the design rationale behind the software architecture, and gives an assessment of the architecture's effectiveness in providing significant performance gains. In particular, we describe the implementation and automatic parallelization of three well-known example applications that contain many fundamental imaging operations: (1) template matching; (2) multi-baseline stereo vision; and (3) line detection. Based on experimental results we conclude that our software architecture constitutes a powerful and user-friendly tool for obtaining high performance in many important image processing research areas. Copyright © 2004 John Wiley & Sons, Ltd. [source] Separation, domestic violence, and divorce mediationCONFLICT RESOLUTION QUARTERLY, Issue 4 2006Desmond Ellis DOVE, an instrument designed to assess and manage the risk of domestic violence, was administered to a sequential, random sample of one hundred forty-seven male and female partners prior to their participation in divorce mediation. Nineteen statistically significant predictors of both pre- and post-separation violence and abuse were identified. Conjugal violence and abuse, male partner control, and mental health problems were prominent among predictors of post-separation violence and abuse. Safety plan interventions and referrals aimed at promoting women's safety during and following their participation in divorce mediation are identified in the concluding segment of the paper. [source] Irritants in combination with a synergistic or additive effect on the skin response: an overview of tandem irritation studiesCONTACT DERMATITIS, Issue 6 2006Francisca Kartono Sodium lauryl sulfate (SLS) has often been chosen as a model for irritant contact dermatitis (ICD) to study the effect of irritants in combination (1,14). Recently ,tandem', or sequential, exposures with SLS have been performed to study the mechanism of skin barrier impairment in ICD (1,6, 15). The assessment of reactions have been documented with visual scoring, transepidermal water loss (TEWL), skin colour reflectance measurements, skin blood flow; among which TEWL has been noted as the most sensitive value (16). The matched control groups were treated with either a single exposure to a single irritant or in tandem with the same irritant repeatedly. Synergistic and additive effects have been reported for various tandem pairs of irritants, however, the mechanism for both remains unclear. The results of tandem irritation studies were evaluated to define and investigate the responses produced and deduce a possible mechanism of action. Clinical ramifications, albeit complex, are discussed. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||