2,169 research outputs found

    Comparison of flow and dispersion properties of free and wall turbulent jets for source dynamics characterisation

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    The objective of this paper is to provide an investigation, using large eddy simulations, into the dispersion of aircraft jets in co-flowing take-off conditions. Before carrying out such study, simple turbulent plane free and wall jet simulations are carried out to validate the computational models and to assess the impact of the presence of the solid boundary on the flow and dispersion properties. The current study represents a step towards a better understanding of the source dynamics behind an airplane jet engine during the take-off and landing phases. The information provided from these simulations can be used for future improvements of existing dispersion models

    Classification of very high resolution aerial photos using spectral-spatial convolutional neural networks

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    © 2018 Maher Ibrahim Sameen et al. Classification of aerial photographs relying purely on spectral content is a challenging topic in remote sensing. A convolutional neural network (CNN) was developed to classify aerial photographs into seven land cover classes such as building, grassland, dense vegetation, waterbody, barren land, road, and shadow. The classifier utilized spectral and spatial contents of the data to maximize the accuracy of the classification process. CNN was trained from scratch with manually created ground truth samples. The architecture of the network comprised of a single convolution layer of 32 filters and a kernel size of 3 × 3, pooling size of 2 × 2, batch normalization, dropout, and a dense layer with Softmax activation. The design of the architecture and its hyperparameters were selected via sensitivity analysis and validation accuracy. The results showed that the proposed model could be effective for classifying the aerial photographs. The overall accuracy and Kappa coefficient of the best model were 0.973 and 0.967, respectively. In addition, the sensitivity analysis suggested that the use of dropout and batch normalization technique in CNN is essential to improve the generalization performance of the model. The CNN model without the techniques above achieved the worse performance, with an overall accuracy and Kappa of 0.932 and 0.922, respectively. This research shows that CNN-based models are robust for land cover classification using aerial photographs. However, the architecture and hyperparameters of these models should be carefully selected and optimized

    Rapid screening of β-Globin gene mutations by Real-Time PCR in Egyptian thalassemic children

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    Thalassemia is one of the most common genetic disorders in Egypt. With the total population of 70 million, there are approximately 600,000 affected individuals and more than 20 million thalassemia carriers. Thalassemia is therefore one of the major health problems in Egypt. B-Thalassemias are priority genetic diseases for prevention programs. Rapid genotype characterization is fundamental in the diagnostic laboratory, especially when offering prenatal diagnosis for carrier couples. Introduction of the real time PCR has made a revolution in the time taken for the PCR reactions. We present a method for the diagnosis of the common mutations of the B-thalassemia in Egyptian children & families. The procedure depends on the real-time PCR using specific fluorescently labeled hybridization probes. The melting temperature for each of the specific probes obtained after the PCR reaction permits the identification of the specific mutation. Genotyping of 20 thalassemic children attending the hematology clinic of the children specialized hospital and 10 controls was done using Real-time PCR and the conventional Amplification Refractory Mutation System (ARMS) technique. Analysis revealed identical results to most of the patients and they were further checked by the sequencing results of the DNA samples. The established method is a robust, fast and straight forward assay that allows the detection of the common B-thalassemia mutations in Egypt. The described LightCycler system protocol can rapidly screen for many B-globin gene mutations. African Journal of Health Sciences Vol. 13 (3-4) 2006: pp. 70-7

    Measurement of the Spectroscopy of Orbitally Excited B Mesons at LEP

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    We measure the masses, decay widths and relative production rate of orbitally excited B mesons using 1.25 million hadronic Z decays recorded by the L3 detector. B-meson candidates are inclusively reconstructed and combined with charged pions produced at the primary event vertex. An excess of events above the expected background in the B\pi mass spectrum in the region 5.6-5.8 GeV is interpreted as resulting from the decay B_u,d^** -> B^(*)\pi, where B_u,d^** denotes a mixture of l=1 B-meson states containing a u or a d quark. A fit to the mass spectrum yields the masses and decay widths of the B_1^* and B_2^* spin states, as well as the branching fraction for the combination of l=1 states. In addition, evidence is presented for the existence of an excited B-meson state or mixture of states in the region 5.9-6.0 GeV

    Performance of the CMS Cathode Strip Chambers with Cosmic Rays

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    The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns

    The Influence of Mirror-Visual Feedback on Training-Induced Motor Performance Gains in the Untrained Hand

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    The well-documented observation of bilateral performance gains following unilateral motor training, a phenomenon known as cross-limb transfer, has important implications for rehabilitation. It has recently been shown that provision of a mirror image of the active hand during unilateral motor training has the capacity to enhance the efficacy of this phenomenon when compared to training without augmented visual feedback (i.e., watching the passive hand), possibly via action observation effects [1]. The current experiment was designed to confirm whether mirror-visual feedback (MVF) during motor training can indeed elicit greater performance gains in the untrained hand compared to more standard visual feedback (i.e., watching the active hand). Furthermore, discussing the mechanisms underlying any such MVF-induced behavioural effects, we suggest that action observation and the cross-activation hypothesis may both play important roles in eliciting cross-limb transfer. Eighty participants practiced a fast-as-possible two-ball rotation task with their dominant hand. During training, three different groups were provided with concurrent visual feedback of the active hand, inactive hand or a mirror image of the active hand with a fourth control group receiving no training. Pre- and post-training performance was measured in both hands. MVF did not increase the extent of training-induced performance changes in the untrained hand following unilateral training above and beyond those observed for other types of feedback. The data are consistent with the notion that cross-limb transfer, when combined with MVF, is mediated by cross-activation with action observation playing a less unique role than previously suggested. Further research is needed to replicate the current and previous studies to determine the clinical relevance and potential benefits of MVF for cases that, due to the severity of impairment, rely on unilateral training programmes of the unaffected limb to drive changes in the contralateral affected limb

    Arabic Language Curriculum Development Management at Multilingual Islamic Boarding School: A Case Study of PPM 4 Language Al-Muhibbin

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    In the era of globalization, multilingual mastery is a crucial factor in dealing with the dynamics of the world and increasing competitiveness in various sectors, including in Islamic boarding schools. Multilingual boarding schools are Islamic educational institutions that develop the ability to use several languages. The purpose of this study was to examine the development of the Arabic language curriculum at a multilingual boarding school, namely Modern 4-Language Boarding School Al-Muhibbin. This research uses a descriptive qualitative method with a case study approach. Data collection techniques were interviews, observations, and documentation studies. This study found that curriculum development management takes place through three stages: planning, implementation, and evaluation. In the planning stage, the four-language curriculum is systemized into one with rotational cycle management every six months. However, in various activities the use of Arabic is more dominant. Curriculum implementation is supported by the use of structured teaching materials, the use of technology, the application of bi'ah lughawiyyah, and extracurricular programs. Meanwhile, the evaluation stage is conducted formatively and summatively to assess the effectiveness of learning and provide feedback for continuous improvement. The evaluation results show that there is an improvement in students' skills especially speaking and reading skills

    Honey health benefits and uses in medicine

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    The generation of reactive oxygen species (ROS) and other free radicals during metabolism is an essential and normal process that ideally is compensated through the antioxidant system. However, due to many environmental, lifestyle, and pathological situations, free radicals and oxidants can be produced in excess, resulting in oxidative damage of biomolecules (e.g., lipids, proteins, and DNA). This plays a major role in the development of chronic and degenerative illness such as cancer, autoimmune disorders, aging, cataract, rheumatoid arthritis, cardiovascular, and neurodegenerative diseases (Pham-Huy et al. 2008; Willcox et al. 2004). The human body has several mechanisms to counteract oxidative stress by producing antioxidants, which are either naturally synthetized in situ, or externally supplied through foods, and/or supplements (Pham-Huy et al. 2008).info:eu-repo/semantics/publishedVersio

    Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

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    The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO
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