503 research outputs found
Eleven years of malaria surveillance in a Sudanese village highlights unexpected variation in individual disease susceptibility and outbreak severity
An analysis is presented of continuous data collected over 11 years based on 1 902 600 person/days of observation on the malaria experience of the people of Daraweesh, a village in eastern Sudan. Malaria transmission is hypo-endemic: the acquisition of clinical immunity with age is not as obvious as in more holo-endemic areas and malaria remained a problem in all age groups throughout the study. However, this population, who are of Fulani origin, showed a distinctly variable level of disease susceptibility. Thirty-two percent of the village never reported malaria symptoms or required malaria treatment while others experienced up to 8 clinical episodes over the 11 years of observation. Malaria incidence was clearly influenced by drought but much less obviously by rainfall. To what extent outbreak patterns are explicable in terms of anopheline factors, and to human immune factors, remains an interesting question for malaria modelling in this, and in other low transmission zones, such as the burgeoning urban areas of modern Africa
Chronic Plasmodium falciparum infections in an area of low intensity malaria transmission in the Sudan
Chronic Plasmodium falciparum malaria infections in a Sudanese village, in an area of seasonal and unstable malaria transmission, were monitored and genetically characterized to study the influence of persistent infection on the immunology and epidemiology of low endemicity malaria. During the October-December malaria season of 1996, 51 individuals out of a population of 420 had confirmed and treated P. falciparum malaria in the village of Daraweesh in eastern Sudan. In a cross-sectional survey carried out in December 1996, an additional 6 individuals were found to harbour a microscopically negative but polymerase chain reaction (PCR)-positive P. falciparum infection. On 1 January 1997, a cohort of 43 individuals aged from 9 to 53, recruited from this group of recently malaria-infected individuals agreed to donate fortnightly blood samples for the next 9 months, the first 6 of which constitute the long Sudanese dry season when transmission falls to undetectable levels. Each blood sample was tested for the presence of persistent malaria infection by microscopy and PCR. Parasite-positive samples were genotyped using PCR assays that detect allelic polymorphism at the MSP-1, MSP-2 and GLURP marker gene loci. Of 43 individuals 16 were found to maintain chronic P. falciparum infections which were continuously genetically characterized
Environmental life cycle assessment and techno-economic analysis of triboelectric nanogenerators
As the world economy grows and industrialization of the developing countries increases, the demand for energy continues to rise. Triboelectric nanogenerators (TENGs) have been touted as having great potential for low-carbon, non-fossil fuel energy generation. Mechanical energies from, amongst others, body motion, vibration, wind and waves are captured and converted by TENGs to harvest electricity, thereby minimizing global fossil fuel consumption. However, only by ascertaining performance efficiency along with low material and manufacturing costs as well as a favorable environmental profile in comparison with other energy harvesting technologies, can the true potential of TENGs be established. This paper presents a detailed techno-economic lifecycle assessment of two representative examples of TENG modules, one with a high performance efficiency (Module A) and the other with a lower efficiency (Module B) both fabricated using low-cost materials. The results are discussed across a number of sustainability metrics in the context of other energy harvesting technologies, notably photovoltaics. Module A possesses a better environmental profile, lower cost of production, lower CO2 emissions and shorter energy payback period (EPBP) compared to Module B. However, the environmental profile of Module B is slightly degraded due to the higher content of acrylic in its architecture and higher electrical energy consumption during fabrication. The end of life scenario of acrylic is environmentally viable given its recyclability and reuse potential and it does not generate toxic gases that are harmful to humans and the environment during combustion processes due to its stability during exposure to ultraviolet radiation. Despite the adoption of a less optimum laboratory manufacturing route, TENG modules generally have a better environmental profile than commercialized Si based and organic solar cells, but Module B has a slightly higher energy payback period than PV technology based on perovskite-structured methyl ammonium lead iodide. Overall, we recommend that future research into TENGs should focus on improving system performance, material optimization and more importantly improving their lifespan to realize their full potential
Comparative evaluation of genetic algorithm-based test case optimization
Software testing is a crucial phase in software development process although it consumes more time and cost of software development. Researchers have proposed several approaches focusing on helping software testers to reduce the execution time and cost of the testing process. Test case optimization is a multi-objective approach that has become one of the best solutions to overcome these problems. Test case optimization focusing on reducing the number of test cases in the test suite that may reduce the overall testing time, cost and effort of software testers especially in regression testing. This paper presents the comparative evaluation between test case optimization techniques that are based on Genetic Algorithm (GA). The evaluation is based on five criteria i.e. technique objectives, applied fitness function, contributions, the percentage of the reduced test cases, fault detection capability, and technique limitations. The evaluation results able identify the gaps in the existing GAbased test case optimization approaches and provide insight in determining the potential research directions in this area.Keywords: Test case optimization, regression testing, multi-objectives, genetic algorithm, software testin
Effect of Feeding Benzoic acid on Performance of Broiler Chickens
The research was conducted to determine the influence of benzoic acid on growth performance, carcass traits, blood parameters and meat chemical composition of broiler birds. The research was carried out using 90 three weeks old broilers (Ross 308) divided into three groups, 30 per each. The levels of inclusion of the benzoic acid was based on treatment 1 (control) 0%, treatment 2 = 0.4% and treatment 3 = 0.8%. Results showed that, feeding benzoic acid to broilers had no significant on body weight, weight gain, feed intake and feed conversion at the two tested levels. Carcass traits did not show significant differences for the treatments, with the exception of bursa weight significantly increased. The serum total protein and globulin were significantly (P<0.05) increased in benzoic acid supplemented broilers. However, no significant differences were observed in serum albumin, triglyceride, cholesterol and uric acid between different experimental groups. No significant differences were observed for hematological parameters among all treated groups. There were no significant differences in chemical composition of broilers meat, including dry matter, protein and ash content. It could be concluded that, dietary inclusion of benzoic acid at both levels improved the immune response by increasing the weight of bursa of Fabricius and elevating blood globulin level but did not affect broiler chickens growth performance
Production of Lambda and Sigma^0 hyperons in proton-proton collisions
This paper reports results on simultaneous measurements of the reaction
channels pp -> pK+\Lambda and pp -> pK+\Sigma^0 at excess energies of 204, 239,
and 284 MeV (\Lambda) and 127, 162, and 207 MeV (\Sigma^0). Total and
differential cross sections are given for both reactions. It is concluded from
the measured total cross sections that the high energy limit of the cross
section ratio is almost reached at an excess energy of only about 200 MeV. From
the differential distributions observed in the overall CMS as well as in the
Jackson and helicity frames, a significant contribution of interfering nucleon
resonances to the \Lambda production mechanism is concluded while resonant
\Sigma^0-production seems to be of lesser importance and takes place only
through specific partial waves of the entrance channel. The data also indicate
that kaon exchange plays a minor role in the case of \Lambda- but an important
role for \Sigma^0-production. Thus the peculiar energy dependence of the
\Lambda-to-\Sigma^0 cross section ratio appears in a new light as its
explanation requires more than mere differences between the p\Lambda and the
p\Sigma^0 final state interaction. The data provide a benchmark for theoretical
models already available or yet to come.Comment: 18 pages, 10 figures; accepted by The European Physical Journal A
(EPJ A
Effect of Feeding Probiotic on Performance of Broiler Ducks Fed Different Protein Levels
The present study was performed to investigate the effect of feeding Saccharomyces cerevisiae (probiotic) with different protein levels on duck performance, carcass traits and blood parameters. A total number of 40 two weeks old Molar ducklings randomly distributed into 4 equal groups.The first group was fed on control diet (16% CP) without any feed additives, while groups 2, 3 and 4 (T2, T3 and T4) were fed on basal diets containing 16, 14 and 12% CP respectively and supplemented with probiotic. Additives was probiotic, thepax (Saccharomyces cerevisiae), at 0.1% of the grower-finisher diet. The results showed that, birds fed on 16% protein diet supplemented with probiotic recorded significantly the best live body weight, body weight gain, feed intake and feed conversion compared with other treatments. There were no significant differences in hot carcass percentage, eviscerated percentage, dressing percentage and relative percentage of internal organs (gizzard, heart, liver and spleen), total protein and triglycerides, between different experimental groups. While there were significant (P<0.05) differences in serum albumin, globulin, cholesterol and uric acid between control group and other treatments. The relative economic feed efficiency was the highest in birds fed 16%protein diets supplemented with Saccharomyces cerevisiae compared with other treated groups. It could be concluded that, dietary inclusion of 0.1% S.cerevisiae in 16% protein diet improved body weight, weight gain, feed intake and feed conversion ratio and carcass traits
Effect of Feeding Citric Acid on Performance of Broiler Ducks Fed Different Protein Levels
The present study was performed to investigate the effect of feeding citric acid with different protein levels on duck performance, carcass traits and blood parameters. A total number of 40 two weeks old Molar ducklings were randomly distributed into 4 equal groups, each of 10. The control diet was formulated to contain approximately crude protein (CP) (16%) and metabolizable energy (3000 kcal/kg diet) as recommended by NRC (1994). The first group was fed on control diet (16% CP) without any feed additives, while groups 2, 3 and 4 (T2, T3 and T4) were fed on basal diets containing 16, 14 and 12% CP respectively and supplemented with citric acid at 1.50% of the grower-finisher diet. The results showed that, birds fed on 16% protein diet supplemented with citric acid recorded significantly the best live body weight, body weight gain, feed intake and feed conversion compared with other treatments. There were no significant differences in hot carcass percentage, eviscerated percentage, dressing percentage and relative percentage of internal organs (gizzard, heart, liver and spleen) between different experimental groups. There were no significant differences in the level of serum total protein and triglycerides, while there were significant (P<0.05) differences in serum albumin, globulin, cholesterol and uric acid between control group and other treatments. There were no significant differences in the intestinal pH between different experimental groups. The relative economic feed efficiency was the highest in birds fed 16% protein diet supplemented with citric acid compared with other treated groups. It could be concluded that, dietary inclusion of 1.50 % citric acid in 16% protein diet improved body weight, weight gain, feed intake and feed conversion ratio and carcass traits
Classification of visualization exudates fundus images results using support vector machine
This paper classifies the characteristics of normal and exudates fundus images by determine its accuracy for diagnostic purposes. Image normalization was performed on 149 fundus images (81 normal and 68 exudates) from MESSIDOR databases to standardize the colours in the fundus images. The OD removed fundus image and fundus image with the exudates areas removed. The SVM1 classifier was applied to 30 test fundus images to determine the best optimal parameter. The kernel function settings; linear, polynomial, quadratic and RBF have an effect on the classification results. For SVM1, the best parameter in classifying pixels is linear kernel function. The visualization results using CAC and radar chart are classified using ts accuracy. It has proven to discriminated exudates and non exudates pixels in fundus image using linear kernel function of SVM1 to diagnose DR.Keywords: Diabetic retinopathy (DR); Optic disc (OD); Support Vector Machine (SVM); AC); Radial Basis Function (RBF)
Detection of asphyxia in infants using deep learning Convolutional Neural Network (CNN) trained on Mel Frequency Cepstrum Coefficient (MFCC) features extracted from cry sounds
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