2,167 research outputs found

    Finite element approximation for a delayed generalized Burgers-Huxley equation with weakly singular kernels: Part I Well-posedness, Regularity and Conforming approximation

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    The analysis of a delayed generalized Burgers-Huxley equation (a non-linear advection-diffusion-reaction problem) with weakly singular kernels is carried out in this work. Moreover, numerical approximations are performed using the conforming finite element method (CFEM). The existence, uniqueness and regularity results for the continuous problem have been discussed in detail using the Faedo-Galerkin approximation technique. For the numerical studies, we first propose a semi-discrete conforming finite element scheme for space discretization and discuss its error estimates under minimal regularity assumptions. We then employ a backward Euler discretization in time and CFEM in space to obtain a fully-discrete approximation. Additionally, we derive a prior error estimates for the fully-discrete approximated solution. Finally, we present computational results that support the derived theoretical results

    Jet-powered Outflows in Supermassive Black Hole Binary Candidate SDSS J1048+0055

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    The search and study of close pairs of supermassive black holes (SMBHs) is important in the study of galaxy mergers which can possibly trigger active galactic nucleus (AGN) activity, and in the context of their evolution into the gravitational wave emitting regime. The quasar SDSS~J1048+0055 was identified as a SMBH binary candidate based on the observed double-peaked \OIIIλλ\lambda\lambda4959,5007 emission lines and two distinct radio components separated by 20\sim 20~pc \citep{2004ApJ...604L..33Z}. To ascertain the binary nature of this source, we analyzed multi-frequency, multi-epoch very long baseline interferometry (VLBI) data to investigate its pc-scale radio properties. The source shows double components with the western feature being brighter than the eastern one. This brighter component has a brightness temperature of 1010\sim 10^{10}~K, spectral index of α=0.09±0.09\alpha = -0.09 \pm 0.09 (flat) and is indicative of mildly relativistic beaming. In contrast, the faint component has a lower brightness temperature of 1089\sim 10^{8-9}~K and steep spectrum. These clues are consistent with a core--jet structure, moreover, the apparent separation speed between the two components is much higher than the expected orbital motion in a binary SMBH. Thus the present study excludes the association of the two VLBI components with the cores of a SMBH binary, although the SMBH binary possibility (e.g., a pair of radio-loud and radio-quiet AGNs) is not fully ruled out. In the single active galactic nucleus (AGN) scenario, the double-peaked optical emission lines can originate from the jet interacting with the narrow-line region as indicated by a change in the jet direction at \sim 140 pc.Comment: Accepted for publication in ApJ. (13 pages, 2 figures, and 2 tables

    Diagnosis of COVID-19 Using Chest X-ray

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    Covid-19 is also a wide spreading infective agent disease that infects humans. A clinical study of COVID-19 infected patients has shown that these kinds of patients are square measure principally infected from a respiratory organ infection when come in contact with this disease. Chest xray (i.e., radiography) a less complicated imaging technique for identification respiratory organ connected issues. Deep learning is that the foremost undefeated technique of machine learning, that provides helpful analysis to review an oversize quantity of chest x-ray pictures which may critically impact on screening of Covid-19. Throughout this work, we have taken the PA read of chest x-ray scans for covid-19 affected patients conjointly as healthy patients. We have used deep learning-based CNN models and compared their performance. We have equate ResNeXt models and inspect their precision to investigate the model presentation, 6432 chest x-ray scans samples square measure collected from the Kaggle repository. This work solely core on potential ways of cluster covid-19 infected patients

    Usporedna procjena različitih postupaka lančane reakcije polimerazom uz prethodnu reverznu transkripciju za dokaz gena F i N virusa kuge malih preživača u kliničkim uzorcima.

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    In the present study the diagnostic value of different sets of F and N gene based primers currently used for diagnosis of Peste des petits ruminants (PPR) by reverse transcription polymerase chain reaction (RT-PCR) were assessed by comparing it with Sandwich ELISA (S-ELISA). A total of five primer pairs, consisting of two pairs (F1/F2 and Fb1/Fb2) amplifying two different regions of F gene and three pairs amplifying different regions of N gene (NP3/NP4, pprn_fr2/pprn_rev and N1/N2) were compared on 10 clinical samples (4 blood, 4 nasal swabs and 2 tissue samples) collected from animals suspected for PPR. The primer sets NP3/NP4 detected highest number of positive samples 6 out of 10 followed by N1/N2 (5/10). Both F-gene based primers (F1/ F2 and Fb1/Fb2) detected 3 out of 10 samples as positive. Whereas the primer pair pprn_fr2/pprn_rev did not yield the desired amplicon in any of the samples tested. The maximum sensitivity and specififi city of 100% was observed by NP3 and NP4 primer based RT-PCR whereas, 0% sensitivity was recorded by pprn_fr2/pprn_rev which fail to detect any positive sample. The overall agreement of 100% with kappa value 1.00 was highest between S-ELISA and NP3 and NP4 primer based RT-PCR suggesting an almost perfect agreement, followed by N1/N2, having kappa value of 0.800, suggesting a substantial agreement. Results thus obtained in the present study, suggest that F-gene primers based RT-PCR can be easily replaced by highly sensitive and specific N-gene primers based RT-PCR for detection of PPR virus nucleic acid.Istražena je dijagnostička vrijednost različitih početnica za gene F i N koje se sada rabe za dijagnosticiranje kuge malih preživača lančanom reakcijom polimerazom uz prethodnu reverznu transkripciju u usporedbi sa sendvič imunoenzimnim testom (S-ELISA). Testirano je ukupno pet parova početnica: dva para (F1/F2 i Fb1/Fb2) specifična za različita područja gena F i tri para specifična za različita područja gena N (NP3/NP4, pprn_fr2/pprn_rev i N1/N2). Njihova vrijednost bila je uspoređena pretragom 10 kliničkih uzoraka (četiri uzorka krvi, četiri uzorka nosnog obriska i dva uzorka tkiva) uzetih od životinja pod sumnjom na kugu malih preživača. Uporabom početnica NP3/NP4 dokazan je najveći broj pozitivnih uzoraka (6/10), a potom početnicom N1/N2 (5/10). Objema početnicama za gen F (F1/F2 i Fb1/Fb2) dokazana su tri pozitivna uzorka (3/10). Par početnice pprn_fr2/pprn_rev nije dao željeni umnožak (amplikon) ni u jednom pretraženom uzorku. Osjetljivost i specifičnost od 100% dokazana je za početnice NP3 i NP4, dok pprn_fr2/pprn_rev nisu pokazale nikakvu reakciju te njihovom upotrebom nije dokazan nijedan pozitivan uzorak. Podudarnost od 100% s kappa vrijednošću 1,00 bila je najveća između S-ELISA-e te RT-lančane reakcije polimerazom upotrebom početnica NP3 i NP4 što govori o posvemašnjoj podudarnosti, dok je na drugom mjestu po podudarnosti bila početnica N1/N2 s kappa vrijednošću od 0,800. Rezultati pokazuju da se RT-lančana reakcije polimerazom upotrebom početnica za gen F može zamijeniti vrlo osjetljivom i specifičnom reakcijom uz upotrebu početnica za gen N za dokazivanje nukleinske kiseline virusa kuge malih preživača

    A cosmic microscope to probe the Universe from Present to Cosmic Dawn - dual-element low-frequency space VLBI observatory

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    A space-based very long baseline interferometry (VLBI) programme, named as the Cosmic Microscope, is proposed to involve dual VLBI telescopes in the space working together with giant ground-based telescopes (e.g., Square Kilometre Array, FAST, Arecibo) to image the low radio frequency Universe with the purpose of unraveling the compact structure of cosmic constituents including supermassive black holes and binaries, pulsars, astronomical masers and the underlying source, and exoplanets amongst others. The operational frequency bands are 30, 74, 330 and 1670 MHz, supporting broad science areas. The mission plans to launch two 30-m-diameter radio telescopes into 2,000 km x 90,000 km elliptical orbits. The two telescopes can work in flexibly diverse modes: (i) space-ground VLBI. The maximum space-ground baseline length is about 100,000 km; it provides a high-dynamic-range imaging capacity with unprecedented high resolutions at low frequencies (0.4 mas at 1.67 GHz and 20 mas at 30 MHz) enabling studies of exoplanets and supermassive black hole binaries (which emit nanoHz gravitational waves); (ii) space-space single-baseline VLBI. This unique baseline enables the detection of flaring hydroxyl masers, and more precise position measurement of pulsars and radio transients at milli-arcsecond level; (iii) single dish mode, where each telescope can be used to monitor transient bursts and rapidly trigger follow-up VLBI observations. The large space telescope will also contribute in measuring and constraining the total angular power spectrum from the Epoch of Reionization. In short, the Cosmic Microscope offers astronomers the opportunity to conduct novel, frontier science.Comment: Accepted for publication in Chinese Journal of Space Science, 10 pages, 2 figure

    Assessment of Special Care Newborn Units in India

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    The neonatal mortality rate in India is high and stagnant. Special Care Newborn Units (SCNUs) have been set up to provide quality level II newborn-care services in several district hospitals to meet this challenge. The units are located in some remotest districts where the burden of neonatal deaths is high, and access to special newborn care is poor. The study was conducted to assess the functioning of SCNUs in eight rural districts of India. The evaluation was based on an analysis of secondary data from the eight units that had been functioning for at least one year. A cross-sectional survey was also conducted to assess the availability of human resources, equipment, and quality care. Descriptive statistics were used for analyzing the inputs (resources) and outcomes (morbidity and mortality). The rate of mortality among admitted neonates was taken as the key outcome variable to assess the performance of the units. Chi-square test was used for analyzing the trend of case-fatality rate over a period of 3-5 years considering the first year of operationalization as the base. Correlation coefficients were estimated to understand the possible association of case-fatality rate with factors, such as bed:doctor ratio, bed:nurse ratio, average duration of stay, and bed occupancy rate, and the asepsis score was determined. The rates of admission increased from a median of 16.7 per 100 deliveries in 2008 to 19.5 per 100 deliveries in 2009. The case-fatality rate reduced from 4% to 40% within one year of their functioning. Proportional mortality due to sepsis and low birthweight (LBW) declined significantly over two years (LBW <2.5 kg). The major reasons for admission and the major causes of deaths were birth asphyxia, sepsis, and LBW/prematurity. The units had a varying nurse:bed ratio (1:0.5-1:1.3). The bed occupancy rate ranged from 28% to 155% (median 103%), and the average duration of stay ranged from two days to 15 days (median 4.75 days). Repair and maintenance of equipment were a major concern. It is possible to set up and manage quality SCNUs and improve the survival of newborns with LBW and sepsis in developing countries, although several challenges relating to human resources, maintenance of equipment, and maintenance of asepsis remain

    "Caught by the eye of sound" : epigastric swelling due to xiphisternal tuberculosis

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    BACKGROUND: Common causes of an epigastric mass include hepatomegaly, pancreatic pseudocyst and epigastric hernia, less common causes being carcinoma of the stomach or pancreas, whereas diseases of the sternum presenting as an epigastric swelling is extremely uncommon. We report a case of tubercular infection of the sternum located in the xiphoid process resulting in its presentation as an epigastric swelling. CASE REPORT: A 30-year-old immunocompetent woman with complaints of an epigastric swelling and undocumented pyrexia for four months was referred for sonographic evaluation with a clinical suspicion of an incompletely treated liver abscess. The patient was examined with ultrasound, sternal radiographs, CT and MRI. Ultrasound revealed a heterogeneous epigastric collection with linear echogenic components suggestive of bone fragments. These appearances suggested chronic infective osteomyelitis of the xiphoid process of the sternum. Lateral chest radiograph demonstrated lytic destruction of the xiphisternum. Tubercular etiology was considered and further evaluation with Multidetector Computed tomography (MDCT) and Magnetic Resonance Imaging (MRI) demonstrated erosive osteomyelitis of the xiphoid process with enhancing inflammation and collection in the adjoining soft tissue. Ultrasound-guided aspiration, PCR and Amplified Mycobacterium tuberculosis DNA test confirmed tubercular infection. CONCLUSIONS: We report a new case of osteo-articular tuberculosis localized to the xiphisternum, a rare clinical entity with an extremely unusual clinical presentation as an epigastric mass. The role of ultrasound in primary diagnosis and as an interventional diagnostic modality for guided aspiration is highlighted

    Fast-BoW: Scaling Bag-of-Visual-Words Generation

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    The bag-of-visual-words (BoW) generation is a widely used unsupervised feature extraction method for the variety of computer vision applications. However, space and computational complexity of bag-of-visual-words generation increase with an increase in the size of the dataset because of computational complexities involved in underlying algorithms. In this paper, we present Fast-BoW, a scalable method for BoW generation for both hard and soft vector-quantization with time complexities O(|h| log2 k) and O(|h|k), respectively1. We replace the process of finding the closest cluster center with a softmax classifier which improves the cluster boundaries over k-means and also can be used for both hard and soft BoW encoding. To make the model compact and faster, we quantize the real weights into integer weights which can be represented using few bits (2−8) only. Also, on the quantized weights, we apply the hashing to reduce the number of multiplications which makes the process further faster. We evaluated the proposed approach on several public benchmark datasets. The experimental results outperform the existing hierarchical clustering tree-based approach by ≈ 12 times

    Assessment of Special Care Newborn Units in India

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    The neonatal mortality rate in India is high and stagnant. Special Care Newborn Units (SCNUs) have been set up to provide quality level II newborn-care services in several district hospitals to meet this challenge. The units are located in some remotest districts where the burden of neonatal deaths is high, and access to special newborn care is poor. The study was conducted to assess the functioning of SCNUs in eight rural districts of India. The evaluation was based on an analysis of secondary data from the eight units that had been functioning for at least one year. A cross-sectional survey was also conducted to assess the availability of human resources, equipment, and quality care. Descriptive statistics were used for analyzing the inputs (resources) and outcomes (morbidity and mortality). The rate of mortality among admitted neonates was taken as the key outcome variable to assess the performance of the units. Chi-square test was used for analyzing the trend of case-fatality rate over a period of 3-5 years considering the first year of operationalization as the base. Correlation coefficients were estimated to understand the possible association of case-fatality rate with factors, such as bed:doctor ratio, bed:nurse ratio, average duration of stay, and bed occupancy rate, and the asepsis score was determined. The rates of admission increased from a median of 16.7 per 100 deliveries in 2008 to 19.5 per 100 deliveries in 2009. The case-fatality rate reduced from 4% to 40% within one year of their functioning. Proportional mortality due to sepsis and low birthweight (LBW) declined significantly over two years (LBW &lt;2.5 kg). The major reasons for admission and the major causes of deaths were birth asphyxia, sepsis, and LBW/prematurity. The units had a varying nurse:bed ratio (1:0.5-1:1.3). The bed occupancy rate ranged from 28% to 155% (median 103%), and the average duration of stay ranged from two days to 15 days (median 4.75 days). Repair and maintenance of equipment were a major concern. It is possible to set up and manage quality SCNUs and improve the survival of newborns with LBW and sepsis in developing countries, although several challenges relating to human resources, maintenance of equipment, and maintenance of asepsis remain

    Radio Observations of Four Active Galactic Nuclei Hosting Intermediate-mass Black Hole Candidates: Studying the Outflow Activity and Evolution

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    Observational searches for intermediate-mass black holes (IMBHs; 102-106 M ⊙) include relatively isolated dwarf galaxies. For those that host active galactic nuclei (AGNs), the IMBH nature may be discerned through the accretion-jet activity. We present radio observations of four AGN-hosting dwarf galaxies, which potentially harbor IMBHs. Very large array (VLA) observations indicate steep spectra (indices of −0.63 to −1.05) between 1.4 and 9 GHz. However, a comparison with the 9 GHz in-band spectral index shows a steepening for GH047 and GH158 (implying older/relic emission) and flattening for GH106 and GH163 (implying recent activity). Overlapping emission regions in the VLA 1.4 GHz and our very long baseline array (VLBA) 1.5 GHz observations, and possibly symmetric pc-scale extensions, are consistent with recent activity in the latter two. Using the compact VLBA radio luminosity, X-ray luminosity (probing the accretion activity), and the black hole masses, all AGNs are found to lie on the empirical fundamental plane relation. The four AGNs are radio-quiet with relatively higher Eddington ratios (0.04-0.32) and resemble X-ray binaries during spectral state transitions that entail an outflow ejection. Furthermore, the radio to X-ray luminosity ratio log R X of −3.9 to −5.6 in these four sources support the scenarios that include corona mass ejection from the accretion disk and wind activity. The growth to kpc-scales likely proceeds along a similar trajectory to young AGNs and peaked spectrum sources. These complex clues can thus aid in the detection and monitoring of IMBHs in the nearby universe
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