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Indirect Approach (indirect + approach)
Selected AbstractsDoes modified interpretation bias influence automatic avoidance behaviour?APPLIED COGNITIVE PSYCHOLOGY, Issue 3 2010Wolf-Gero Lange Cognitive bias modification (CBM) studies suggest a causal role of interpretation biases in the aetiology and maintenance of Social Anxiety Disorder. However, it is unknown if the effects of induced biases transfer to behaviour. In two analogue studies, behavioural changes in response to aversive and positive stimuli were measured after the induction of positive and negative interpretation biases in ,averagely anxious' participants. Responses to emotional multi-facial displays (,crowds') were measured using an indirect Approach,Avoidance Task (AAT). The crowds comprised different ratios of either neutral and angry faces or happy and angry faces. In Experiment 1, negatively trained participants (NETs) showed a faster avoidance response for the neutral,angry crowds when the number of angry pictures in the crowd increased. This response pattern resembles the one previously found in socially anxious individuals. Experiment 2 replicated the effect of the cognitive bias manipulation on conceptually comparable material, but did not show transfer to the behavioural task. These studies add to the body of knowledge regarding successful modification of interpretive bias and generalizability to a behavioural task. Copyright © 2010 John Wiley & Sons, Ltd. [source] The Use of Hemastix® and the Subsequent Lack of DNA Recovery Using the Promega DNA IQTM SystemJOURNAL OF FORENSIC SCIENCES, Issue 6 2009Hiron Poon M.Sc. Abstract:, Following implementation of our automated process incorporating the Promega DNA IQTM system as a DNA extraction method, a large number of blood-containing exhibits failed to produce DNA. These exhibits had been tested with the Hemastix® reagent strip, commonly used by police investigators and forensic laboratories as a screening test for blood. Some exhibits were even tainted green following transfer of the presumptive test reagents onto the samples. A series of experiments were carried out to examine the effect of the Hemastix® chemistries on the DNA IQTM system. Our results indicate that one or more chemicals imbedded in the Hemastix® reagent strip severely reduce the ability to recover DNA from any suspected stain using the DNA IQTM magnetic bead technology. The 3,3,,5,5,-tetramethylbenzidine (TMB) used as the reporting dye appears to interact with the magnetic beads to prevent DNA recovery. Hydrogen peroxide does not seem to be involved. The Hemastix® chemistries do not interfere in any way with DNA extraction performed using phenol-chloroform. The incompatibility of the Hemastix® chemistries on the DNA IQTM system forced us to adopt an indirect approach using filter paper to carry out the presumptive test. [source] Computational optimal control of the terminal bunt manoeuvre,Part 2: minimum-time caseOPTIMAL CONTROL APPLICATIONS AND METHODS, Issue 5 2007S. Subchan Abstract This is the second part of a paper studies trajectory shaping of a generic cruise missile attacking a fixed target from above. The problem is reinterpreted using optimal control theory resulting in a minimum flight time problem; in the first part the performance index was time-integrated altitude. The formulation entails non-linear, two-dimensional (vertical plane) missile flight dynamics, boundary conditions and path constraints, including pure state constraints. The focus here is on informed use of the tools of computational optimal control, rather than their development. The formulation is solved using a three-stage approach. In stage 1, the problem is discretized, effectively transforming it into a non-linear programming problem, and hence suitable for approximate solution with DIRCOL and NUDOCCCS. The results are used to discern the structure of the optimal solution, i.e. type of constraints active, time of their activation, switching and jump points. This qualitative analysis, employing the results of stage 1 and optimal control theory, constitutes stage 2. Finally, in stage 3, the insights of stage 2 are made precise by rigorous mathematical formulation of the relevant two-point boundary value problems (TPBVPs), using the appropriate theorems of optimal control theory. The TPBVPs obtained from this indirect approach are then solved using BNDSCO and the results compared with the appropriate solutions of stage 1. The influence of boundary conditions on the structure of the optimal solution and the performance index is investigated. The results are then interpreted from the operational and computational perspectives. Copyright © 2007 John Wiley & Sons, Ltd. [source] Cost-effectiveness of prenatal screening for thalassaemia in Hong KongPRENATAL DIAGNOSIS, Issue 11 2004K. Y. Leung Abstract Objectives To determine the cost effectiveness of a universal prenatal screening program for ,- and ,-thalassaemia. Methods We retrospectively reviewed our program from 1998 to 2002, and calculated the direct and indirect costs of various components. Results 18 936 women were screened at our prenatal clinic and 153 couples were subsequently referred to our Prenatal Diagnostic Centre for counselling and further investigations. In addition, there were 238 tertiary referrals and 157 self-referrals. After investigations, 84 fetuses were at risk of ,-thalassaemia major/,-E thalassaemia, 19 of them were affected and 18 were aborted. The total expenditure on our program (HK$10.0 million) would be less than the postnatal service costs (HK$40.4 million) for 18,-thalassaemia major fetuses if they were born. Of 361 women at risk of carrying a homozygous ,0 -thalassaemia fetus, 311 (86.2%) opted for the indirect approach (using serial ultrasound examinations to exclude Hb Bart's disease), and 76 (24.5%) subsequently underwent an invasive test for a definitive diagnosis. The sensitivity and false positive rate of this indirect approach was 100.0% and 2.9% respectively. Conclusion It is cost effective to run a universal prenatal screening program in an area where both ,-thalassaemia and ,-thalassaemia are prevalent. The indirect approach can effectively avoid an invasive test in unaffected pregnancies. Copyright © 2004 John Wiley & Sons, Ltd. [source] Metabolic control analysis of an enzymatic biofuel cellBIOTECHNOLOGY & BIOENGINEERING, Issue 6 2009Doris J. Glykys Abstract Metabolic control analysis (MCA) is an analytical technique that aims to quantify the distribution of control that enzymes exhibit over the steady-state fluxes through a metabolic network. In an enzymatic biofuel cell, the flux of interest is the electrical current generated by the system. Regardless of transport limitations and other constraints, kinetic limitations can become potential bottlenecks in the operation of a biofuel cell. We have used an indirect approach to MCA to investigate a common osmium-mediated glucose oxidase/laccase enzymatic biofuel cell. The results of the analysis show that the control of the electron flux strongly depends on the total mediator concentrations and the extent of polarization of the individual electrodes. The effect of varying oxygen concentrations is also examined, as oxygen is required for the cathode, but it participates in a non-productive reaction at the anode. Under normal operating conditions the electrodes will be highly polarized and will both contain high mediator concentrations. This configuration will result in a dominant FCC at the anode, and the conditions that are needed for balanced flux control between the anode and cathode are explored. As increasingly complex bioelectrocatalytic systems and architectures are envisioned, MCA will be a valuable framework to facilitate their design and subsequent operation. Biotechnol. Bioeng. 2009;102: 1624,1635. © 2008 Wiley Periodicals, Inc. [source] Does size matter for dispersal distance?GLOBAL ECOLOGY, Issue 4 2007David G. Jenkins ABSTRACT Aim, The aim of this study is to answer the questions: (1) do small organisms disperse farther than large, or vice versa; and (2) does the observed pattern differ for passive and active dispersers? These questions are central to several themes in biogeography (including microbial biogeography), macroecology, metacommunity ecology and conservation biology. Location, The meta-analysis was conducted using published data collected worldwide. Methods, We collected and analysed 795 data values in the peer-reviewed literature for direct observations of both maximal dispersal distance and mass of the dispersing organisms (e.g. seeds, not trees). Analysed taxa ranged in size from bacteria to whales. We applied macroecology analyses based on null models (using Monte Carlo randomizations) to test patterns relative to specific hypotheses. Results, Collected dispersal distance and mass data spanned 9 and 21 orders of magnitude, respectively. Active dispersers dispersed significantly farther (P < 0.001) and were significantly greater in mass (P < 0.001) than passive dispersers. Overall, size matters: larger active dispersers attained greater maximum observed dispersal distances than smaller active dispersers. In contrast, passive-disperser distances were random with respect to propagule mass, but not uniformly random, in part due to sparse data available for tiny propagules. Conclusions, Size is important to maximal dispersal distance for active dispersers, but not for passive dispersers. Claims that microbes disperse widely cannot be tested by current data based on direct observations of dispersal: indirect approaches will need to be applied. Distance,mass relationships should contribute to a resolution of neutral and niche-based metacommunity theories by helping scale expectations for dispersal limitation. Also, distance,mass relationships should inform analyses of latitudinal species richness and conservation biology topics such as fragmentation, umbrella species and taxonomic homogenization. [source] The use of marker-based relationship information to estimate the heritability of body weight in a natural population: a cautionary taleJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 1 2002S. C. Thomas A number of procedures have been developed that allow the genetic parameters of natural populations to be estimated using relationship information inferred from marker data rather than known pedigrees. Three published approaches are available; the regression, pair-wise likelihood and Markov Chain Monte Carlo (MCMC) sib-ship reconstruction methods. These were applied to body weight and molecular data collected from the Soay sheep population of St. Kilda, which has a previously determined pedigree. The regression and pair-wise likelihood approaches do not specify an exact pedigree and yielded unreliable heritability estimates, that were sensitive to alteration of the fixed effects. The MCMC method, which specifies a pedigree prior to heritability estimation, yielded results closer to those determined using the known pedigree. In populations of low average relationship, such as the Soay sheep population, determination of a reliable pedigree is more useful than indirect approaches that do not specify a pedigree. [source] | ||||||||||