16,940 research outputs found
Declining Burden of Malaria Over two Decades in a Rural Community of Muheza District, North-Eastern Tanzania.
No full textThe recently reported declining burden of malaria in some African countries has been attributed to scaling-up of different interventions although in some areas, these changes started before implementation of major interventions. This study assessed the long-term trends of malaria burden for 20 years (1992--2012) in Magoda and for 15 years in Mpapayu village of Muheza district, north-eastern Tanzania, in relation to different interventions as well as changing national malaria control policies.\ud
Repeated cross-sectional surveys recruited individuals aged 0 -- 19 years from the two villages whereby blood smears were collected for detection of malaria parasites by microscopy. Prevalence of Plasmodium falciparum infections and other indices of malaria burden (prevalence of anaemia, splenomegaly and gametocytes) were compared across the years and between the study villages. Major interventions deployed including mobile clinic, bed nets and other research activities, and changes in national malaria control policies were also marked. In Magoda, the prevalence of P. falciparum infections initially decreased between 1992 and 1996 (from 83.5 to 62.0%), stabilized between 1996 and 1997, and further declined to 34.4% in 2004. A temporary increase between 2004 and 2008 was followed by a progressive decline to 7.2% in 2012, which is more than 10-fold decrease since 1992. In Mpapayu (from 1998), the highest prevalence was 81.5% in 1999 and it decreased to 25% in 2004. After a slight increase in 2008, a steady decline followed, reaching <5% from 2011 onwards. Bed net usage was high in both villages from 1999 to 2004 (>=88%) but it decreased between 2008 and 2012 (range, 28% - 68%). After adjusting for the effects of bed nets, age, fever and year of study, the risk of P. falciparum infections decreased significantly by >=97% in both villages between 1999 and 2012 (p < 0.001). The prevalence of splenomegaly (>40% to <1%) and gametocytes (23% to <1%) also decreased in both villages.Discussion and conclusionsA remarkable decline in the burden of malaria occurred between 1992 and 2012 and the initial decline (1992 -- 2004) was most likely due to deployment of interventions, such as bed nets, and better services through research activities. Apart from changes of drug policies, the steady decline observed from 2008 occurred when bed net coverage was low suggesting that other factors contributed to the most recent pattern. These results suggest that continued monitoring is required to determine causes of the changing malaria epidemiology and also to monitor the progress towards maintaining low malaria transmission and reaching related millennium development goals
Author Co-Citation Analysis (ACA): a powerful tool for representing implicit knowledge of scholar knowledge workers
No full textIn the last decade, knowledge has emerged as one of the most important and valuable organizational assets. Gradually this importance caused to emergence of new discipline entitled ―knowledge management‖. However one of the major challenges of knowledge management is conversion implicit or tacit knowledge to explicit knowledge. Thus Making knowledge visible so that it can be better accessed, discussed, valued or generally managed is a long-standing objective in knowledge management. Accordingly in this paper author co- citation analysis (ACA) will be proposed as an efficient technique of knowledge visualization in academia (Scholar knowledge workers)
Evaluating firms’ R&D performance using best worst method
No full textSince research and development (R&D) is the most critical determinant of the productivity, growth and competitive advantage of firms, measuring R&D performance has become the core of attention of R&D managers, and an extensive body of literature has examined and identified different R&D measurements and determinants of R&D performance. However, measuring R&D performance and assigning the same level of importance to different R&D measures, which is the common approach in existing studies, can oversimplify the R&D measuring process, which may result in misinterpretation of the performance and consequently fallacy R&D strategies. The aim of this study is to measure R&D performance taking into account the different levels of importance of R&D measures, using a multi-criteria decision-making method called Best Worst Method (BWM) to identify the weights (importance) of R&D measures and measure the R&D performance of 50 high-tech SMEs in the Netherlands using the data gathered in a survey among SMEs and from R&D experts. The results show how assigning different weights to different R&D measures (in contrast to simple mean) results in a different ranking of the firms and allow R&D managers to formulate more effective strategies to improve their firm's R&D performance by applying knowledge regarding the importance of different R&D measures.Transport and Logistic
Identification of the Kna/Knb polymorphism and a method for Knops genotyping
No full textDNA mutations resulting in the McCoy and Swain-Langley polymorphisms have been identified on complement receptor 1 (CR1)-a ligand for rosetting of Plasmodium falciparum-infected RBCs. The molecular identification of the Kna/Knb polymorphism was sought to develop a genotyping method for use in the study of the Knops blood group and malaria
Preservice Teachers' Development of Effective Approaches to Text-based Discussion
No full textText-based discussion is a dialogic instructional practice to promote reading comprehension among students. To enact this practice, a teacher engages students in authentic conversation about text as students read it, to assist them in building understanding of text ideas as they are encountered. Text-based discussion has the potential to promote the development of both low-level and high-level comprehension skills among students, yet teachers need support in learning to enact it. Research has indicated that text-based discussion is not well-represented in classrooms today, likely because not many teachers have access to this support.
Recently, some teacher educators have focused on teaching preservice teachers (PSTs) to enact text-based discussions during teacher preparation programs, in an attempt to increase the presence of the practice in classrooms. Practice-based methods courses have been developed which attempt to provide preservice teachers with the knowledge and skill needed to enact text-based discussions successfully. This study investigated the ways in which six preservice teachers’ enactments of text-based discussion developed over the course of their one-year student teaching placements, after completing one such methods course in which they learned to enact the practice.
Data were collected at three time points during student teaching, and included transcripts of enactments of text-based discussion, lesson plans, interview transcripts, and assessments of lesson quality using the Instructional Quality Instrument (Junker et al., 2004). Analysis of the data suggested that the PSTs entered student teaching with the ability to enact text-based discussions with a moderate level of success, and that the quality of the discussions continued to improve over the course of the school year. The methods course seemed to support PSTs in learning to link student comments and press students for accuracy and reasoning. PSTs were more successful in eliciting student linking and recall of explicit text information than in eliciting elaborated responses from students; the participation structure enforced by the PST seemed to influence the extent to which students provided elaborated responses. This study supports the use of practice-based methods courses to teach PSTs to enact text-based discussions, and uncovers several areas that are in need of additional focus during these courses
Global and local energy dissipation in a turbulent Von Kármán flow
No full textWe use PIV measurements to study local and global energy transfer in a Von Kármán flow. First, we use a Large Eddy Simulation (LES) approximation to model and compute the injected and dissipated power. This procedure involves a free parameter that is calibrated using angular momentum balance. We then estimate the local and global mean injected and dissipated power for several types of impellers, for various Reynolds numbers and for various flow topologies. These PIV-estimates are then compared with direct injected power estimates, provided by torque measurements at the impellers. The agreement between PIV-estimates and direct measurements depends on the flow topology. In symmetric situations, our estimates capture 30 to 70% of the actual energy dissipation. However, our results become increasingly inaccurate as the shear layer responsible for most of the dissipation is approaching one of the impeller, where it cannot be resolved by our PIV set-up. Finally, we show that a very good agreement between PIV-estimates and direct estimates of the dissipated power is obtained using a new method based on the work of Duchon and Robert that generalizes Kármán-Horwath equation to non-isotropic, non homogeneous flows. This method provides parameter-free estimates of the energy dissipation as long as the smallest resolved scale lies in the inertial range
A model reduction method for a class of 2-D systems
No full textA decomposition-aggregation scheme for reduction of dimensionality for a class of 2-D systems is introduced. This method, which is based upon the extension of the singular perturbation method in two dimensions, is used to decompose the original 2-D system into two reduced-order 2-D subsystems. These reduced order subsystems are shown to effectively capture the dynamical behavior of the original full-order system. Two numerical examples are provided that indicate the effectiveness of this method when used in image modeling applications.This work was supported in part by the Natural Sciences and Engineering Research Council of Canada, and by Fonds Pour la Formation de Chercheurs et L'aide la Recherche, Programme E'tablissment de Nouveaux Chercheurs
AN AUTOMATIC METHOD FOR CLASSIFYING MEDICAL RESEARCHERS INTO DOMAIN SPECIFIC SUBGROUPS
No full textObjective:This dissertation developed an automatic classification procedure, as an example of a novel tool for an informationist, which extracts information from published abstracts, classifies abstracts into their "fields of study," and then determines the researcher's "field of study" and "level of activity." Method: This dissertation compared a domain expert's method of classification and an automatic classification procedure on a random sample of 101 medical researchers (derived from a potential list of 305 medical researchers) and their associated abstracts. Design: The study design is a retrospective, cross-sectional, inter-rater agreement study, designed to compare two classification methods (i.e., automatic classification procedure and domain expert). The study population consists of University of Pittsburgh, School of Medicine, Department of Medicine (DOM) professionals who (1) have published at least one article listed in PubMed® as first or last author and/or (2) are the primary investigator for at least one grant listed in CRISP.Main outcome measures: Three outcome measures were derived from the domain expert's versus automatic categorization procedure: (1) an abstract's "field of study," (2) a researcher's "field of study" and (3) a researcher's "level of activity and field of study." Results: Kappa showed moderate agreement between automatic and domain expert classification for the abstracts' "field of study" (Kappa = 0.535, n = 504, p < .000). Kappa showed moderate agreement between automatic and domain expert classification of the researcher's "field of study" (Kappa = 0.535, n = 101, p < .000). Kappa showed good agreement between automatic and domain expert classification of the researcher's "level of activity and field of study" (Kappa = 0.634, n = 101, p < .000). Conclusion: The study suggests that an automatic library classification procedure can provide rapid classification of medical research abstracts into their "fields of study." The classification procedure can also process multiple abstracts' "fields of study" and classify their associated medical researchers into their "field of study" and "level of activity and field of study." The classification procedure, used as a tool by an informationist, can be used as the basis for new services
An improved semi-analytical method for 3D slope reliability assessments
No full textAn improved semi-analytical method for calculating the reliability of 3D slopes with spatially varying shear strength parameters is proposed. The response of an existing semi-analytical method has been compared with that of the computationally more intensive, but more general, random finite element method (RFEM), demonstrating that the simpler method underestimates the failure probability. An alternative relationship for the expected failure length and two correction factors are proposed, which modify the original formulation of the simpler method. The proposed approach gives substantially improved results that compare favourably with those obtained by RFEM, and therefore provides a more accurate simplified solution.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Geo-engineerin
An Efficient Deflation Method applied on 2-D and 3-D Bubbly Flow Problems
No full textSimulating bubbly flows is a very popular topic in CFD. These bubbly flows are governed by the Navier-Stokes equations. In many popular operator splitting formulations for these equations, solving the linear system coming from the discontinuous Poisson equation takes the most computational time, despite of its elliptic nature. ICCG is widely used for this purpose, but for complex bubbly flows this method shows slow convergence. As alternative for ICCG, we apply a deflated variant of ICCG which is called DICCG. This new method incorporates the eigenmodes corresponding to the components which caused the slow convergence of ICCG. Some implementation issues of DICCG are discussed in this paper and some considerations about the singularity are made. Moreover, coarse linear systems have to be solved within DICCG. We discuss methods to do this efficiently which results in two approaches DICCG1 and DICCG2. In exact arithmetics, we prove that these variants lead to the same convergence results. Thereafter we show with numerical experiments that both DICCG approaches are very efficient. Compared to ICCG, DICCG decreases significantly the number of iterations and the computational time as well, which are required for solving Poisson equation in applications of 2-D and 3-D bubbly flows.Electrical Engineering, Mathematics and Computer Scienc
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