1,799 research outputs found
Skylab-EREP studies in computer mapping of terrain in the Cripple Creek-Canon City area of Colorado
Get PDFMultispectral-scanner data from satellites are used as input to computers for automatically mapping terrain classes of ground cover. Some major problems faced in this remote-sensing task include: (1) the effect of mixtures of classes and, primarily because of mixtures, the problem of what constitutes accurate control data, and (2) effects of the atmosphere on spectral responses. The fundamental principles of these problems are presented along with results of studies of them for a test site of Colorado, using LANDSAT-1 data
The mixture problem in computer mapping of terrain: Improved techniques for establishing spectral signatures, atmospheric path radiance, and transmittance
Get PDFThere are no author-identified significant results in this report
Recommended from our members
Age-related changes to lumbosacral spinal cord motoneurons that modulate bladder and bowel functions in male C57BL/6 mice
Get PDFIncontinence and sexual dysfunction are often increased in the aged human population. In rats and mice the pattern of micturition and faecal clearance also changes with ageing and is suggestive of bladder and bowel dysfunction
Advancing Competitive Policy in the Legislative Arena: Florida\u27s Experience in Sunset Review of Surface Transportation Regulation
Get PDFAn XML format for benchmarks in High School Timetabling
Get PDFThe High School Timetabling Problem is amongst the most widely used timetabling problems. This problem has varying structures in different high schools even within the same country or educational system. Due to lack of standard benchmarks and data formats this problem has been studied less than other timetabling problems in the literature. In this paper we describe the High School Timetabling Problem in several countries in order to find a common set of constraints and objectives. Our main goal is to provide exchangeable benchmarks for this problem. To achieve this we propose a standard data format suitable for different countries and educational systems, defined by an XML schema. The schema and datasets are available online
Development of basic theories and techniques for determining stresses in rotating turbine or compressor blades
Get PDFA method for measuring in-plane displacement of a rotating structure by using two laser speckle photographs is described. From the displacement measurements one can calculate strains and stresses due to a centrifugal load. This technique involves making separate speckle photographs of a test model. One photograph is made with the model loaded (model is rotating); the second photograph is made with no load on the model (model is stationary). A sandwich is constructed from the two speckle photographs and data are recovered in a manner similar to that used with conventional speckle photography. The basic theory, experimental procedures of this method, and data analysis of a simple rotating specimen are described. In addition the measurement of in-plane surface displacement components of a deformed solid, and the application of the coupled laser speckle interferometry and boundary-integral solution technique to two dimensional elasticity problems are addressed
Contrasting patterns of insecticide resistance and knockdown resistance (kdr) in the dengue vectors Aedes aegypti and Aedes albopictus from Malaysia
Get PDFBackground
Knowledge on the extent, distribution and mechanisms of insecticide resistance is essential for successful insecticide-based dengue control interventions. Here, we report an extensive resistance profiling of the dengue vectors Aedes aegypti and Aedes albopictus across Malaysia and establish the contribution of knockdown resistance mechanism revealing significant contrast between both species.
Methods
Aedes mosquitoes were collected from four states in Malaysia in 2010 using ovitraps and tested against six major insecticides using WHO bioassays. Knockdown resistance (kdr) was investigated in both species.
Results
A moderate resistance to temephos was detected from samples collected in 2010 in Penang, Kuala Lumpur, Johor Bharu and Kota Bharu (1.5 < RR < 3.3). A widespread and multiple resistances was observed in Ae. aegypti particularly against pyrethroids, DDT and bendiocarb. Mosquitoes from Kuala Lumpur consistently had the highest resistance levels and was the only population showing a moderate resistance to malathion (91% mortality). The resistance profile of Ae. albopictus contrasted to Ae. aegypti with full susceptibility to pyrethroids except in Kuala Lumpur where moderate resistance is observed. PBO synergist assays suggest metabolic resistance mechanisms play a major role in resistance in both species. Two kdr mutations, F1534C and V1016G, were detected in Ae. aegypti across Malaysia but neither of these mutations were found in Ae. albopictus. Additionally, signatures of selection were detected on the Voltage-gated sodium channel gene in Ae. aegypti but not in Ae. albopictus. The presence of the 1534C allele was significantly associated with pyrethroid resistance and an additive effect to pyrethroid resistance was observed in individuals containing both kdr alleles.
Conclusions
Findings from this study will help to design and implement successful insecticide-based interventions against Ae. aegypti and Ae. albopictus to improve dengue control across Malaysia
Identifying permethrin resistance loci in malaria vectors by genetic mapping
Get PDFIdentification of the major loci responsible for insecticide resistance in malaria vectors would aid the development andimplementation of effective resistance management strategies, which are urgently needed to tackle the growing threat posedby resistance to the limited insecticides available for malaria control. Genome-wide association studies in the major malariavector, Anopheles gambiae, have been hindered by the high degree of within-population structuring and very low levels oflinkage disequilibrium hence we revisited the use of quantitative trait loci (QTL) mapping to study resistance phenotypesin this vector species. Earlier work, identified two major QTL associated with pyrethroid resistance in A. gambiae s.s. fromEast Africa using genetic crossing of laboratory-colonized resistant and susceptible strains. In this study, we report theresults from genetic mapping of pyrethroid resistance in three isofemale pedigrees established from wild-caught femaleA. gambiae s.s. mosquitoes from Benin. We identified two QTL on chromosomes 2L and 3R in these field populations, insimilar genomic locations to theQTLidentified in laboratory strains. The relative merits of two alternative study designs arediscussed and suggestions made for future genetic mapping studies of insecticide resistance in mosquitoes
Recommended from our members
Editorial
Get PDFWelcome to the second edition of the International Journal for Researcher Development. In this issue, we are pleased to include an in-depth study on the professionality of researchers per se. In her article, ‘Developing research capacity in the social sciences: a professionality-based model’ Linda Evans draws attention to the importance of both developing a research culture and developing researchers themselves. She suggests that leadership in research is failing to achieve the development of institutional research capacity to an acceptable standard whilst researchers themselves are unaware of the necessity to develop continually. In our next article, Fowler and colleagues present evidence from a recent study as to the factors that are necessary to facilitate the building of research capacity in the UK. In their article, ‘Building research capacity across the UK: evidence from recent initiatives in England, Scotland and Wales’ they recommend more explicit institutional commitment to the professional development of research staff and suggest that this should include the facilitation of mentoring relationships between more and less experienced researchers. The paper by Pitcher and Akerlind provides an international slant by presenting results of a novel study using metaphor analysis across several Australian Universities. This enabled conceptions of research by researchers to be categorized. Finally, we include a report on discussions based around evaluating developmental activities for researchers in higher education. In the UK, Roberts funding came on-line in 2002 to support the development of skills training for post-graduate researchers – to assist their employability. That tranche of funding is nearing its end and universities across the UK are now having to evaluate the worth of the products of that funding and how to fund it, if at all, in the future. The Gough report on the discussions surrounding the development of an evaluation approach make interesting reading
Insecticide resistance in Anopheles arabiensis in Sudan: temporal trends and underlying mechanisms
Get PDFBackground: Malaria vector control in Sudan relies mainly on indoor residual spraying (IRS) and the use of long lasting insecticide treated bed nets (LLINs). Monitoring insecticide resistance in the main Sudanese malaria vector, Anopheles arabiensis, is essential for planning and implementing an effective vector control program in this country.
Methods: WHO susceptibility tests were used to monitor resistance to insecticides from all four WHO-approved classes of insecticide at four sentinel sites in Gezira state over a three year period. Insecticide resistance mechanisms were studied using PCR and microarray analyses.
Results: WHO susceptibility tests showed that Anopheles arabiensis from all sites were fully susceptible to bendiocarb and fenitrothion for the duration of the study (2008–2011). However, resistance to DDT and pyrethroids was detected at three sites, with strong seasonal variations evident at all sites. The 1014 F kdr allele was significantly associated with resistance to pyrethroids and DDT (P 7 in allelic tests). The 1014S allele was not detected in any of the populations tested. Microarray analysis of the permethrinresistant population of An. arabiensis from Wad Medani identified a number of metabolic genes that were significantly over-transcribed in the field-collected resistant samples when compared to the susceptible Sudanese An. arabiensis Dongola strain. These included CYP6M2 and CYP6P3, two genes previously implicated in pyrethroid resistance in Anopheles gambiae s.s, and the epsilon-class glutathione-S-transferase, GSTe4.
Conclusions: These data suggest that both target-site mechanisms and metabolic mechanisms play an important role in conferring pyrethroid resistance in An. arabiensis from Sudan. Identification in An. arabiensis of candidate loci that have been implicated in the resistance phenotype in An. gambiae requires further investigation to confirm the role of these genes
- …
