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Careful Control (careful + control)
Selected AbstractsGenome-wide association studies for discrete traitsGENETIC EPIDEMIOLOGY, Issue S1 2009Duncan C. Thomas Abstract Genome-wide association studies of discrete traits generally use simple methods of analysis based on ,2 tests for contingency tables or logistic regression, at least for an initial scan of the entire genome. Nevertheless, more power might be obtained by using various methods that analyze multiple markers in combination. Methods based on sliding windows, wavelets, Bayesian shrinkage, or penalized likelihood methods, among others, were explored by various participants of Genetic Analysis Workshop 16 Group 1 to combine information across multiple markers within a region, while others used Bayesian variable selection methods for genome-wide multivariate analyses of all markers simultaneously. Imputation can be used to fill in missing markers on individual subjects within a study or in a meta-analysis of studies using different panels. Although multiple imputation theoretically should give more robust tests of association, one participant contribution found little difference between results of single and multiple imputation. Careful control of population stratification is essential, and two contributions found that previously reported associations with two genes disappeared after more precise control. Other issues considered by this group included subgroup analysis, gene-gene interactions, and the use of biomarkers. Genet. Epidemiol. 33 (Suppl. 1):S8,S12, 2009. © 2009 Wiley-Liss, Inc. [source] Deep Start: a hybrid strategy for automated performance problem searchesCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 11-12 2003Philip C. Roth Abstract To attack the problem of scalability of performance diagnosis tools with respect to application code size, we have developed the Deep Start search strategy,a new technique that uses stack sampling to augment an automated search for application performance problems. Our hybrid approach locates performance problems more quickly and finds performance problems hidden from a more straightforward search strategy. The Deep Start strategy uses stack samples collected as a by-product of normal search instrumentation to select deep starters, functions that are likely to be application bottlenecks. With priorities and careful control of the search refinement, our strategy gives preference to experiments on the deep starters and their callees. This approach enables the Deep Start strategy to find application bottlenecks more efficiently and more effectively than a more straightforward search strategy. We implemented the Deep Start search strategy in the Performance Consultant, Paradyn's automated bottleneck detection component. In our tests, Deep Start found half of our test applications' known bottlenecks between 32% and 59% faster than the Performance Consultant's current search strategy, and finished finding bottlenecks between 10% and 61% faster. In addition to improving the search time, Deep Start often found more bottlenecks than the call graph search strategy. Copyright © 2003 John Wiley & Sons, Ltd. [source] The Effects of Moisture in Low-Voltage Organic Field-Effect Transistors Gated with a Hydrous Solid ElectrolyteADVANCED FUNCTIONAL MATERIALS, Issue 16 2010Nikolai Kaihovirta Abstract The concept of using ion conducting membranes (50,150 ,m thick) for gating low-voltage (1 V) organic field-effect transistors (OFETs) is attractive due to its low-cost and large-area manufacturing capabilities. Furthermore, the membranes can be tailor-made to be ion conducting in any desired way or pattern. For the electrolyte gated OFETs in general, the key to low-voltage operation is the electrolyte "insulator" (the membrane) that provides a high effective capacitance due to ionic polarization within the insulator. Hydrous ion conducting membranes are easy to process and readily available. However, the role of the water in combination with the polymeric semiconductor has not yet been fully clarified. In this work electrical and optical techniques are utilized to carefully monitor the electrolyte/semiconductor interface in an ion conducting membrane based OFET. The main findings are that 1) moisture plays a major part in the transistor operation and careful control of both the ambient atmosphere and the potential differences between the electrodes are required for stable and consistent device behavior, 2) the obtained maximum effective capacitance (5 ,F cm,2) of the membrane suggests that the electric double layer is distributed over a broad region within the polyelectrolyte, and 3) electromodulation spectroscopy combined with current,voltage characteristics provide a method to determine the threshold gate voltage from an electrostatic field-effect doping to a region of (irreversible) electrochemical perturbation of the polymeric semiconductor. [source] Au@pNIPAM Thermosensitive Nanostructures: Control over Shell Cross-linking, Overall Dimensions, and Core GrowthADVANCED FUNCTIONAL MATERIALS, Issue 19 2009Rafael Contreras-Cáceres Abstract Thermoresponsive nanocomposites comprising a gold nanoparticle core and a poly(N -isopropylacrylamide) (pNIPAM) shell are synthesized by grafting the gold nanoparticle surface with polystyrene, which allows the coating of an inorganic core with an organic shell. Through careful control of the experimental conditions, the pNIPAM shell cross-linking density can be varied, and in turn its porosity and stiffness, as well as shell thickness from a few to a few hundred nanometers is tuned. The characterization of these core,shell systems is carried out by photon-correlation spectroscopy, transmission electron microscopy, and atomic force microscopy. Additionally, the porous pNIPAM shells are found to modulate the catalytic activity, which is demonstrated through the seeded growth of gold cores, either retaining the initial spherical shape or developing a branched morphology. The nanocomposites also present thermally modulated optical properties because of temperature-induced local changes of the refractive index surrounding the gold cores. [source] Tunable Arrays of C60 Molecular Chains,ADVANCED MATERIALS, Issue 3 2008L. Chen Tunable arrays of C60linear chains on the ,-sexithiophene (6T) bilayer or monolayer surface nanotemplates are formed by careful control of the delicate balance between the intermolecular and the interfacial interactions using different experimental conditions, that is, various C60 and 6T surface coverages and post-annealing temperatures. The figure shows scanning tunneling microscopy images of the arrays. [source] PO2 Dependence of the Diffuse-Phase Transition in Base Metal Capacitor DielectricsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 1 2006Daniel E. McCauley The diffuse-phase transition in BaTiO3 -based dielectrics for capacitor applications has been studied with respect to its dependence on oxygen partial pressure during sintering. Understanding the mobility of this transition is critical in developing next generation dielectrics for ultra thin (,1 ,m) applications while maintaining the appropriate temperature stability and insulation resistance. Historically, a heterogeneous core/shell microstructure was developed to maintain temperature stability. However, in fired grains of ,250 nm (required for layers ,1 ,m) a well-defined core/shell structure is very difficult to establish. The results from this study demonstrate that careful control of the diffuse-phase transition addresses some of these problems. [source] Preparation and characterization of bis- ortho -diynylarene (BODA)-derived submicrogratingsPOLYMER ENGINEERING & SCIENCE, Issue 12 2007Huseyin Zengin The objective of this study was to illustrate how submicrogratings can be prepared from bis- ortho -diynylarene (BODA)-derived polymers. BODA monomers undergo thermal step-growth polymerization and careful control of this conversion, with respect to molecular weight and viscosity, can be used to produce reactive, processable branched polyarlyene intermediates. "Soft-lithography" techniques were used to prepare submicrogratings from these intermediates, which were subsequently stabilized by further polymerization. The surface morphology and dimensions of the submicrogratings were examined using scanning electron microscopy techniques and crystallinity was studied. Reflectivity data was also obtained from linear submicrogratings. These BODA-derived microstructures can be carbonized at 1000°C, or above, to obtain carbonized microstructures with potential for application in optical and electronic microdevices. POLYM. ENG. SCI., 47:2095,2099, 2007. © 2007 Society of Plastics Engineers [source] Improved imaging resolution in desorption electrospray ionization mass spectrometry,RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 17 2008Vilmos Kertesz The imaging resolution of desorption electrospray ionization mass spectrometry (DESI-MS) was investigated using printed patterns on paper and thin-layer chromatography (TLC) plate surfaces. Resolution approaching 40,µm was achieved with a typical DESI-MS setup, which is approximately 5 times better than the best resolution reported previously. This improvement was accomplished with careful control of operational parameters (particularly spray tip-to-surface distance, solvent flow rate, and spacing of lane scans). In addition, an appropriately strong analyte/surface interaction and uniform surface texture on the size scale no larger than the desired imaging resolution were required to achieve this resolution. Overall, conditions providing the smallest possible effective desorption/ionization area in the DESI impact plume region and minimizing the analyte redistribution on the surface during analysis led to improved DESI-MS imaging resolution. Published in 2008 by John Wiley & Sons, Ltd. [source] | ||||||||||