167 research outputs found
Corrigendum: Performance evaluation of five commercial assays in assessing seroprevalence of HEV antibodies among blood donors
No full textThe affiliation for author Lukman Thalib was incorrectly listed as number 5. It should have been listed as number 3. Please see corrected author and affiliation list below:
Enas S. Al-Absi,1,2 Duaa W. Al- Sadeq,1 Manaf H. Younis,3 Hadi M. Yassine,2 Omnya M. Abdalla,1 Areej G. Mesleh,1 Tameem A. Hadwan,1 Joshua O. Amimo,4,5 Lukman Thalib,3 and Gheyath K. Nasrallah1,2,*
1 Department of Biomedical Science, College of Health Sciences, Qatar University, Doha, Qatar
2 Biomedical Research Center, Qatar University, Doha, Qatar
3 Department of Public Health, College of Health Sciences, Qatar University, Doha, Qatar
4 Department of Animal Production, Faculty of Veterinary Medicine University of Nairobi, Nairobi, Kenya
5 Biosciences of Eastern and Central Africa-International Livestock Research Institute (BecA-ILRI), Nairobi, Kenya
The authors apologize for any inconvenience caused.
© 2019 The AuthorsNo Full Tex
Interferometric Synthetic Aperture Radar (SAR) Missions Employing Formation Flying
No full textThis paper presents an overview of single-pass interferometric Synthetic Aperture Radar (SAR) missions employing two or more satellites flying in a close formation. The simultaneous reception of the scattered radar echoes from different viewing directions by multiple spatially distributed antennas enables the acquisition of unique Earth observation products for environmental and climate monitoring. After a short introduction to the basic principles and applications of SAR interferometry, designs for the twin satellite missions TanDEM-X and Tandem-L are presented. Primary objective of TanDEM-X (TerraSAR-X add-on for Digital Elevation Measurement) is the generation of a global Digital Elevation Model (DEM) with unprecedented accuracy as the basis for a wide range of scientific research, as well as for commercial DEM production. This goal is achieved by enhancing the TerraSAR-X mission with a second TerraSAR-X like satellite that will be launched in spring 2010. Both satellites act then as a large single-pass SAR interferometer with the opportunity for flexible baseline selection. Building upon the experience gathered with the TanDEM-X mission design, the fully polarimetric L-band twin satellite formation Tandem-L is proposed. Important objectives of this highly capable interferometric SAR mission are the global acquisition of 3-D forest structure and biomass inventories, large scale measurements of millimetric displacements due to tectonic shifts, and systematic observations of glacier movements. The sophisticated mission concept and the high data acquisition capacity of Tandem-L will moreover provide a unique data source to systematically observe, analyze and quantify the dynamics of a wide range of additional processes in the bio-, litho-, hydro- and cryosphere. By this, Tandem-L will be an essential step to advance our understanding of the Earth system and its intricate dynamics. Enabling technologies and techniques are described in detail and an outlook on future interferometric and tomographic concepts and developments, including multi-static SAR systems with multiple receivers, is provided
Aberrant development of pancreatic beta cells derived from human iPSCs with FOXA2 deficiency
No full text<p>Induced pluripotent stem cells (iPSCs) were generated from a patient with <em>FOXA2 </em>haploinsufficiency (FOXA2<sup>+/-</sup>iPSCs) as well as healthy individual as a control. Then they were differentiated into into all stages of beta cells to understand the role of FOXA2 during pancreatic beta cell development as described in the article entitled "Aberrant development of pancreatic beta cells derived from human iPSCs with FOXA2 deficiency" by Elsayed AK et al. The dataset represent RNA-seq data generated from pancreatic progenitors (PP2) and endocrine progenitors (EP) derived from control iPSCs (Ctr-iPSCs) and from patient-specific FOXA2 haplo-insufficient iPSCs (FOXA2<sup>+/-</sup>iPSCs). </p>
<p>The file name is : Sample name with replicate_overall sample number_read direction_001 where:</p>
<p>- PP2-Ctr R1 and PP2-Ctr R2: Pancreatic progenitors derived from Ctr-iPSCs (control)</p>
<p>-PP2-FOX R1, PP2-FOX R2 and PP2-FOX R3: Pancreatic progenitors derived from FOXA2 haplo-insufficient iPSCs (FOXA2<sup>+/-</sup>iPSCs).</p>
<p>- EP-Ctr R1 and EP-Ctr R2: Endocrine progenitors derived from Ctr-iPSCs (control)</p>
<p>-EP-FOX R1, EP-FOX R2 and EP-FOX R3: Endocrine progenitors derived from FOXA2 haplo-insufficient iPSCs (FOXA2<sup>+/-</sup>iPSCs).</p>
<p>- RNA-seq data was generated from two biological replicates in control and three replicates in patient. </p>
<p>- Read direction: R1 (Forward), R2 (Reverse).</p>
The Influence of temperature on the growth of the nile tilapia, oreochromis niloticus reared in glass tanks
No full textThe effect of three water temperatures: 20, 25 and 30°C on the growth rate of Nile tilapia, Oreochromis ni/oticus was evaluated using a stocking density of 200 fish/mJ. Fish were reared in glass tanks supplied with thermostatic heaters and biological filters. Fish were fed a local fish food (34% protein) in a dry form once daily for six days per week with 2% of fish body weight. The experiment covered a time period of 135 days from Nov. 1993 to Mar. 1994. The best growth rate was obtained at a temperature of25°C followed by the temperature of 30°C, and the lowest growth rate was achieved at 20°c. The optimum temperature for these fish may be 25°C or slightly more but less than 30°C. The effect of the temperature on the growth rate of Nile tilapia was highly significant (P<O.OOI)
Lead Nitrate Induced Histopathological Alterations in the Liver and Intestine of African Catfish Clarias gariepinus Exposed to Sublethal Concentrations
No full text552-557Studies were carried out on the liver and intestine tissue of Clarias gariepinus after exposure to sublethal concentrations of LC50 lead nitrate for 20 days. Fish were distributed into four groups, control (0 mg/L, LC50 of Pb(NO3)2) and three groups exposed to 20, 40 and 60% of the LC50 of Pb(NO3)2 (16.12, 32.24 and 48.37 mg/L respectively). Section of hepatic and intestine tissues showed the normal structure for control group. However, treated hepatic tissues of fish exhibited altered its characteristic architecture, with remarkably high vacuolation in hepatocytes and hepatoctolysis. Also, central vein was dilated and increased hemorrhage in the sections of almost samples from treated fish. Increased number of fibroblasts and Kuppffer cells were observed in the examined sections from treated fish when compared to the control. Therefore, fish treated with 60% LD50 of Pb(NO3)2 observed the proliferation of fibrous in connective tissue particularly near sinusoids and substituting liver parenchyma. Therefore, intestinal sections from the different treated fish groups revealed an evident harmful to intestinal tissue, especially in enterocytes and structures of villi. Also, disturbed longitudinal and circular muscularis were observed, to abnormally dilated, lamina propria, was infiltrated with a huge numbers of inflammatory leukocytes. Mucous secreting goblet cells proliferated and multiplied in all exposed fish
Recommended from our members
Hierarchical Multi-Label Classification: Going Beyond Generalization Trees
No full textTraditional approach to automated classification assumes that each object should be assigned to only one out of two or more classes. However, some real-world applications digress from this generic scenario in two important ways. First, each example can belong to several classes simultaneously (multi-label classification). Second, the classes can be hierarchically ordered in the sense that some are more specific versions of others (hierarchical classification). Seeking to address both of these issues, the presented work deals with “hierarchical multi-label classification”. In non-hierarchical multi-label classification, literature survey indicates that good performance is achieved when a Support Vector Machine (SVM) is used to induce each class separately. This said, some experiments suggest that further improvement can be achieved by explicitly dealing with the problem of imbalanced training sets. The author proposes a solution in terms of a technique referred to as R-SVM; the idea is to re-adjust the SVM-hyperplane offset accordingly. Experiments in the first part of this dissertation rely on data from domains of text-categorization. More important, however, is then the second part that focuses on hierarchical multi-label classification. Here, the author proposes a new technique, HR-SVM, which constitutes a hierarchical extension of R-SVM proceeding in a top-down fashion with a new mechanism to correct errors propagated from classifiers at higher levels of the hierarchy. The system has been subjected to experiments with data from the field of gene function prediction. The results show that the new technique compares favorably with other existing approaches along various performance criteria.</p
Predicting atmospheric refraction with weather modeling and machine learning
No full textThis work details the analysis of time-lapse images with a point-tracking image processing approach along with the use of an extensive numerical weather model to investigate image displacement due to refraction. The model is applied to create refractive profile estimates along the optical path for the days of interest. Ray trace analysis through the model profiles is performed and comparisons are made with the measured displacement results. Additionally, a supervised machine learning algorithm is used to build a predictive model to estimate the apparent displacement of an object, based on a set of measured metrological values taken in the vicinity of the camera. The predicted results again are compared with the field-imagery ones.Atmospheric Remote Sensin
Localized Computation of Newton Updates in Fully-implicit Two-phase Flow Simulation
No full textAbstractFully-Implicit (FI) Methods are often employed in the numerical simulation of large-scale subsurface flows in porous media. At each implicit time step, a Newton-like method is used to solve the FI discrete nonlinear algebraic system. The linear solution process for the Newton updates is the computational workhorse of FI simulations. Empirical observations suggest that the computed Newton updates during FI simulations of multiphase flow are often sparse. Moreover, the level of sparsity observed can vary dramatically from iteration to the next, and across time steps. In several large scale applications, it was reported that the level of sparsity in the Newton update can be as large as 99%. This work develops a localization algorithm that conservatively predetermines the sparsity pattern of the Newton update. Subsequently, only the flagged nonzero components of the system need be solved. The localization algorithm is developed for general FI models of two phase flow. Large scale simulation results of benchmark reservoir models show a 10 to 100 fold reduction in computational cost for homogeneous problems, and a 4 to 10 fold reduction for strongly heterogeneous problems
Fore and Aft Channel Reconstruction in the TerraSAR-X Dual Receive Antenna Mode
No full textThe TerraSAR-X satellite is a high resolution synthetic aperture radar (SAR) system launched in June 2007 which provides the option to split the antenna in along-track direction and sample two physical channels separately. Modern SARs are equipped with active phased array antennas and multiple channels. In order to keep costs low TerraSAR-X uses the redundant receiver unit for the second channel such that fore and aft channel signals are combined by a hybrid coupler to form sum and difference channel data. The dual receive antenna mode can either be used to acquire along-track interferometric data or to acquire signals with different polarizations at the same time (Quad pol). Fore and aft channel reconstruction is necessary if ground moving target indication algorithms such as the displaced phase center antenna technique or along-track interferometry shall be applied, and in order to separate the horizontally and vertically polarized received signal components. The proposed approach uses internal calibration pulses from different calibration beams in order to estimate and compensate the hardware impact. The theoretical framework together with the results from the experimental data evaluation for the fore and aft channel reconstruction of the TerraSAR-X dual receive antenna mode are presented. The impact of the receive hardware transformation matrix estimation accuracy on errors in the reconstructed fore and aft channel image data is studied, and
first examples on the ground moving target indication capability of the TerraSAR-X dual receive antenna mode are given
Bacterial Co-Infection as a Potential Threat to Farmed Flathead Grey Mullet (Mugil cephalus): Phenotypic and Molecular Diagnosis, Histopathology, Immunity Response, and In Vitro Antibacterial Evaluation
No full textVibrio alginolyticus, Vibrio chlorea, and Enterococcus cloacae were the main bacterial pathogens investigated during recurrent episodes of mortalities among farmed flathead grey mullet (Mugil cephalus) in the Bahar El-Baqar area, Sharqia governorate, Egypt, during the summer season in 2021. Nevertheless, the contamination of water with heavy metals was evaluated. In this study, a total number of sixty moribund and freshly dead Mugil cephalus were examined clinically and upon post-mortem. Then, the bacterial isolates were subjected to bacteriological phenotypic examination, 16S rRNA gene sequencing, and antibiotic sensitivity testing. Histopathological screening and the immunity response of naturally infected M. cephalus were also implemented. In areas where bacterial strains were recovered in a high percentage, water contamination with Cu, Fe, and Ni was higher than the permissible limit. The results showed a high similarity (99–100%) to Vibrio and E. cloacae strains using phylogenetic analysis of 16S rRNA. Most isolates exhibited sensitivity to florfenicol, ciprofloxacin, and norfloxacin, while they were resistant to erythromycin and amoxicillin. Hemorrhage, oedema, hemosiderosis, and melanomacrophage activation in most affected tissues of infected M. cephalus were detected by light microscopy. Nevertheless, higher levels of AST and ALT, as well as serum inflammatory markers, CRP, and lysozyme activity, were shown in infected fish. There were higher MDA levels, along with a reduction of GSH, SOD, and catalase, in the gills and brain of infected M. cephalus, compared to the control fish. Our obtained data confirmed the high prevalence of Vibrio serovars and E. cloacae in infected grey mullets, describing their histopathological alterations, higher inflammatory response, and oxidative stress impact. These results could be useful indicators for understanding the pathogenesis of these pathogens in correlation with water parameter deterioration. Thus, the emergence of Vibrio and E. cloacae species in this study threatens the brackish water aquaculture industry in Egypt and poses a public health concern
- …
