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Third Step (third + step)
Selected AbstractsSparse points matching by combining 3D mesh saliency with statistical descriptorsCOMPUTER GRAPHICS FORUM, Issue 2 2008U. Castellani Abstract This paper proposes new methodology for the detection and matching of salient points over several views of an object. The process is composed by three main phases. In the first step, detection is carried out by adopting a new perceptually-inspired 3D saliency measure. Such measure allows the detection of few sparse salient points that characterize distinctive portions of the surface. In the second step, a statistical learning approach is considered to describe salient points across different views. Each salient point is modelled by a Hidden Markov Model (HMM), which is trained in an unsupervised way by using contextual 3D neighborhood information, thus providing a robust and invariant point signature. Finally, in the third step, matching among points of different views is performed by evaluating a pairwise similarity measure among HMMs. An extensive and comparative experimental session has been carried out, considering real objects acquired by a 3D scanner from different points of view, where objects come from standard 3D databases. Results are promising, as the detection of salient points is reliable, and the matching is robust and accurate. [source] Portfolio selection on the Madrid Exchange: a compromise programming modelINTERNATIONAL TRANSACTIONS IN OPERATIONAL RESEARCH, Issue 1 2003E. Ballestero As a contribution to portfolio selection analysis, we develop a compromise programming approach to the investor's utility optimum on the Madrid Online Market. This approach derives from linkages between utility functions under incomplete information, Yu's compromise set, and certain biased sets of portfolios on the efficient frontier. These linkages rely on recent theorems in multi,criteria literature, which allow us to approximate the investor's utility optimum between bounds which are determined either by linear programming models or graphic techniques. Returns on 104 stocks are computed from capital gains and cash,flows, including dividends and rights offerings, over the period 1992,1997. The first step consists in normalizing the mean,variance efficient frontier, which is defined in terms of two indexes, profitability and safety. In the second step, interactive dialogues to elicit the investor's preferences for profitability and safety are described. In the third step, the utility optimum for each particular investor who pursues a buy,&,hold policy is bounded on the efficient frontier. From this step, a number of portfolios close to the investor's utility optimum are obtained. In the fourth step, compromise programming is used again to select one ,satisficing' portfolio from the set already bounded for each investor. This step is new with respect to previous papers in which compromise/utility models are employed. Computing processes are detailed in tables and figures which also display the numerical results. Extensions to active management policies are suggested. [source] A High-Yield, Liquid-Phase Approach for the Partial Oxidation of Methane to Methanol using SO3 as the OxidantADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2005Sudip Mukhopadhyay Abstract A direct approach for producing methanol from methane in a three-step, liquid phase process is reported. In the first step, methane is reacted with SO3 to form methanesulfonic acid (MSA) at 75,°C using a free-radical initiator and MSA as the solvent. Urea-H2O2 in combination with RhCl3 is found to be the most effective initiator (57% conversion of SO3; 7.2% conversion of CH4). MSA is then oxidized by SO3 at 160,°C in a second step to produce a mixture containing methyl bisulfate and some methyl methanesulfonate (87% conversion of MSA). In the third step, the mixture of methyl bisulfate and methyl methanesulfonate is hydrolyzed in the presence of an organic solvent, to produce an organic phase containing methanol and an aqueous phase containing sulfuric acid and some MSA (63% conversion of methyl bisulfate; 72% conversion of methyl methanesulfonate). Overall, 58% of the MSA (of which 23% is derived from methane) is converted to methanol. [source] How issues get framed and reframed when different communities meet: a multi-level analysis of a collaborative soil conservation initiative in the Ecuadorian AndesJOURNAL OF COMMUNITY & APPLIED SOCIAL PSYCHOLOGY, Issue 3 2004Art Dewulf Abstract Drawing on qualitative data from a longitudinal case study of a collaborative soil conservation initiative in southern Ecuador, we study how multiple actors, including university experts, development organizations and local communities, make sense of the issues from different perspectives through the process of issue framing. Starting from an analysis of the actors' usual issue frames, we point out their differences in selecting aspects, connecting them and drawing boundaries around the issues. Bringing in the time dimension leads us to consider how changing patterns of actor involvement and evolving frame configurations mutually influence each other. In a third step, we zoom in on the here-and-now level of ongoing interaction using discourse analysis, outlining an interactive, communicative and discursive approach to dealing with differences in issue framing. We identify various ways of dealing with these differences and argue that approaching them constructively by tuning the different frames into a mutually acceptable configuration is an important challenge for any attempt at integrated management of natural resources. Copyright © 2004 John Wiley & Sons, Ltd. [source] HIGH YIELD PURIFICATION OF DEXTRANSUCRASE FROM LEUCONOSTOC MESENTEROIDES NRRL B-512F BY PHASE PARTITIONINGJOURNAL OF FOOD BIOCHEMISTRY, Issue 1 2006MANISHA NIGAM ABSTRACT The extracellular dextransucrase (sucrose: 1,6-,-D-glucan 6-,-D-glucosyltransferase EC 2.4.1.5) from Leuconostoc mesenteroides NRRL B-512F was purified by phase partitioning using poly(ethylene) glycol (PEG) and dextran generated by dextransucrase. Three steps of repeated phase partitioning by PEG 6000 and PEG 400 showed that the purification of dextransucrase by PEG 6000 was much greater than that obtained by PEG 400. Both the specific activity of 42.1 U/mg and the overall yield of 84% of dextransucrase activity obtained after the third step of phase partitioning by PEG 6000 were significantly higher than that of 23.8 U/mg and 46% overall yield, respectively, by PEG 400 or of that previously reported. The successive three steps, two-phase partitioning with a final concentration of 5% PEG 6000, reproducibly yielded a homogeneous preparation of dextransucrase. [source] GABA synthesis in Schwann cells is induced by the neuroactive steroid allopregnanoloneJOURNAL OF NEUROCHEMISTRY, Issue 4 2010Valerio Magnaghi J. Neurochem. (2009) 112, 980,990. Abstract Recent evidence showed that neurotransmitters are synthesised in glial cells, such as the Schwann cells, which form myelin sheaths in the PNS. While the presence of GABA type A (GABA-A) receptors has been previously demonstrated in these cells, the evidence of GABA synthesis remained still elusive. In an attempt to demonstrate the presence of GABA in rat Schwann cells, we adopted a strategy, using several integrated neurochemical, molecular as well as immunocytochemical approaches. We first demonstrated the presence of glutamic acid decarboxylase of 67 kDa (GAD67) in Schwann cells, a crucial enzyme of the GABA synthesis mechanism. Second, we demonstrated that GABA is synthesized and localized in Schwann cells. As the third step we showed that allopregnanolone (10 nM), a potent allosteric modulator of GABA-A receptors, stimulates GABA synthesis through increased levels of GAD67 in Schwann cells. Analysis of intracellular signalling mechanisms revealed that the protein kinase A pathway, through enhanced cAMP levels and cAMP response element binding protein phosphorylation, modulates the allosteric action of allopregnanolone at the GABA-A receptor in Schwann cells. Our findings are the first to demonstrate that this GABA mechanism is active in Schwann cells thus establishing new potential therapeutic targets to control Schwann cell biology, which may prove useful in the treatment of several neurodegenerative disorders. [source] Synthesis of dendritic macromolecules through divergent iterative thio-bromo "Click" chemistry and SET-LRPJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 15 2009Brad M. Rosen Abstract The development of a novel nucleophilic thio-bromo "Click" reaction, specifically base-mediated thioetherification of thioglycerol with ,-bromoesters was reported in an earlier article. The combination of this thio-bromo click reaction with subsequent acylation with 2-bromopropionyl bromide provides an iterative two-step divergent growth approach to the synthesis of a new class of poly(thioglycerol-2- propionate) (PTP) dendrimers. In this article, the addition of a third step, the single-electron transfer living radical polymerization (SET-LRP) of methyl acrylate (MA), was shown to provides access to a three-step "branch" and "grow" divergent approach to dendritic macromolecules wherein poly(methyl acrylate) (PMA) connects the branching subunits. This facile methodology can provide a diversity of dendritic macromolecular topologies and will ultimately provide the means to the development of self-organizable dendritic macromolecules. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3940,3948, 2009 [source] Ortho Effects in Quantitative Structure Activity Relationships for Lipase Inhibition by Aryl CarbamatesMOLECULAR INFORMATICS, Issue 8 2003Gialih Lin Abstract Ortho -substituted phenyl- N -butyl carbamates (1,11) are synthesized and evaluated for their inhibition effects on Pseudomonas species lipase. Carbamates 1,11 are characterized as pseudo-substrate inhibitors of the enzyme. The logarithms of dissociation constant (Ki), carbamylation constant (k2), and bimolecular inhibition constant (ki) multiply linearly correlate with Hammett substituent constant (,), Taft-Kutter-Hansch ortho steric constant (ES), and Swan-Lupton field constant (F). For ,logKi -, logk2 -, and logki -correlations, values of ,, ,, f, ,XR are 0.2, ,0.06, ,1.7, 0.8; 0.0, 0.0, 1.0, ,0.07; and ,1.8, 7, 0.6, 5; respectively. The enzyme inhibition mechanism is composed of four steps: 1) the first step which is protonation of carbamates 1,11, 2) the second step (Ki1) which involves in the proton 1,3-shift of protonated carbamates 1,11 then the pseudo- trans to cis conformational change, 3) the third step (Ki2) which is formation of a negative charged enzyme-inhibitor tetrahedral intermediate, and 4) the fourth step (k2) which is the carbamylation step. The former three steps are likely composed of the Ki step. There is little ortho steric enhancement effect in the Ki step. From cross-interaction correlations, distance between carbamate and phenyl substituents in transition state for the Ki step is relatively short due to a large ,XR value of 7. The k2 step is insensitive to ortho steric effect. The k2 step involves in departure of leaving group, substituted phenol in which is protonated from the proton 1,3-shift but not from the active site histidine of the enzyme. From cross-interaction correlations, the distance between carbamate and phenyl substituents in transition state for the k2 step is relatively long due to a small ,XR value of 0.6. [source] An inverse estimation of initial temperature profile in a polymer processPOLYMER ENGINEERING & SCIENCE, Issue 1 2008Ali A. Ranjbar Since one of the most important parameter in polymer processing such as injection stretch blow molding is temperature distribution in the thickness direction, an inverse method has been applied to estimate this profile. This process comprises of four steps. In the first step the preform is injection molded, and in the second and third step it is stretched by a rod to its final length and then inflated and in the last step it is discharged from the mold. In such kind of polymer flows viscous dissipation plays a remarkable role in the evolution of temperature profile. Some theoretical temperature profile has been applied to confirm the validation of the inverse algorithm. Different solution techniques are applied in this article to the inverse problem under consideration, namely: the conjugate gradient and Levenberg,Marquardt method. After the preform is injection molded, which is the first step, it is removed from the mold, which corresponds to time t = 0. At this moment an infrared camera is used to record the surface temperature of the preform with a certain time step. With regard to variation of thermal properties with temperature, the inverse problem becomes nonlinear. These experimental data provided by the infrared camera are then used to estimate the temperature profile at the end of injection process before stretching and inflation took place. POLYM. ENG. SCI., 48:133,140, 2008. © 2007 Society of Plastics Engineers [source] Preliminary crystallographic studies of an extremely thermostable KDG aldolase from Sulfolobus solfataricusACTA CRYSTALLOGRAPHICA SECTION D, Issue 11 2000Elaine J. Hendry Crystals have been grown of 2-keto-3-deoxygluconate aldolase (KDG aldolase) from the hyperthermophilic archaeon Sulfolobus solfataricus that diffract to 2.2,Å resolution. The enzyme catalyses the reversible aldol cleavage of 2-keto-3-dexoygluconate to pyruvate and glyceraldehyde, the third step of a modified non-phosphorylated Entner,Doudoroff pathway of glucose oxidation. S. solfataricus grows optimally at 353,K and the enzyme itself has a half-life of 2.5,h,at 373,K. Knowledge of the crystal structure of KDG aldolase will further understanding of the basis of protein hyperthermostability and create a target for site-directed mutagenesis of active-site residues, with the aim of altering substrate specificity. Three crystal forms have been obtained: orthorhombic crystals of space group P212121, which diffract to beyond 2.15,Å, monoclinic crystals of space group C2, which diffract to 2.2,Å, and cubic crystals of space group P4232, which diffract to 3.4,Å. [source] A preliminary X-ray study of d,d -heptose-1,7-bisphosphate phosphatase from Burkholderia thailandensis E264ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 2 2010Mi-Sun Kim d,d -Heptose-1,7-bisphosphate phosphatase (GmhB), which is involved in the third step of the NDP-heptose biosynthesis pathway, converts d,d -heptose-1,7-bisphosphate to d,d -heptose-1-phosphate. This biosynthesis pathway is a target for new antibiotics or antibiotic adjuvants for Gram-negative pathogens. Burkholderia thailandensis is a useful surrogate organism for studying the pathogenicity of melioidosis owing to its extensive genomic similarity to B. pseudomallei. Melioidosis caused by B. pseudomallei is a serious invasive disease of animals and humans in tropical and subtropical areas. In this study, GmhB has been cloned, expressed, purified and crystallized. X-ray data have also been collected to 2.50,Å resolution using synchrotron radiation. The crystal belonged to space group P6, with unit-cell parameters a = 243.2, b = 243.2, c = 41.1,Å. [source] | |||||||||||||