3,351 research outputs found
Machine Learning Algorithms and Auditor’s Assessments of the Risks Material Misstatement: Evidence from the Restatement of Listed London Companies
The purpose of this study is to investigate the relationship between machine learning algorithms and auditors assessments of the risks of material misstatement and restatement. Additionally, a focus on the effect of machine learning algorithms (SVM, Naïve Bayes, and K-means) on misstatement and restatement in London companies. The final sample of the study is 304 firm year observations. Which covers the listed firms on the London Stock Exchange and the period from 2018 to 2020. Especially, the firms that restated their financial statements -even just once- during the study period. The results showed a positive significant effect of machine learning techniques (K-means, Naïve Bayes, and SVM) on the intentional misstatements, which means that using machine learning techniques helps in determining the intentional misstatements. The results also showed a negative significant effect of the same techniques (K-means, Naïve Bayes, and SVM) on the restatements, which means that using machine learning techniques helps in avoiding the restatements
Half-metallicity in EuN: A First-Principles Calculation
We report on the electronic and magnetic properties of the rock salt (RS) and cesium chloride (CsCl) phases of EuN. Our calculation was performed within the framework of the density functional theory (DFT), as implemented in the Wien2k package. We have used the generalized gradient approximation (GGA) for the exchange correlation potential and, in certain, cases the Local Spin Density (LSDA) approximation, with the Hubbard interaction taken into account. Our calculation demonstrates the presence of an energy gap in both of the RS and CsCl structures when only spin-polarized calculation is used. However, taking the Hubbard potential into consideration, via the LSDA+U scheme, led to the disappearance of the energy gap, and hence to the absence of the half-metallic behavior in this system. Keywords: rare-earth nitrides; magnetic moment; DFT; DOS; half metallicity; spin density
THE ANTI-HYPERCHOLESTEROLEMIC EFFECT OF ULVAN POLYSACCHARIDE EXTRACTED FROM THE GREEN ALGA ULVAFASCIATA ON AGED HYPERCHOLESTEROLEMIC RATS
Objective: This study aims to evaluate the relation between hypercholesterolemia and aging, beside the role of Ulva fasciata polysaccharides (UFP)aqueous extracts in lowering cholesterol in aged hypercholesterolemia-induced rats was demonstrated.Method: A total of 140 male Wister rats weighing 120±10 g, 6-9 months old were used. Hypercholesterolemia was induced in rats by feeding ratshigh-fat diet (cholesterol), cholesterol was orally administrated at a dose of (30 mg/0.3 ml olive oil/1 kg animal) 5 times a week for 12 consecutiveweeks, lard fat was mixed with normal diet (1 kg of animal lard was added to 5 kg of normal diet), the occurrence of hypercholesterolemia wasdetermined by measuring the lipid profile (TC, LDL-C, high-density lipoprotein-cholesterol [HDL-C], triglyceride [TG]), the old hypercholesterolemic(HC) rats were only used.Results: The antihypercholesterolemic (HC) effects of ulvan, the sulfated polysaccharide extracted from the green alga Ulvafasciata, in aged rats,were studied. Algal treatment declared a significant reduction in serum total lipid level while, elevation of high-density lipoprotein-cholesterol levelwas noticed in HC rats. Moreover, the algal treatment significantly decreased serum liver and kidney functions biomarkers and improved the hepaticantioxidant levels in hyperlipidemic aged rats. In addition, ulvan administration significantly suppressed the expression of tumor necrosis factoralpha,myeloperoxidaseand cell vascularand intracellularadhesionmolecules-1,whileincreasedthe anti-inflammatorycytokinelevel;interleukin-10.Furthermore,the histopathologicalexaminationof aorta,liverandkidneyof HC-treatedratsindicatedthatthe Ulvafasciatapolysaccharides(UFP),isapotentnaturalhypolipidemicnutraceuticalforthe ameliorationof hyperlipidemiain aged rats.Conclusion: It could be concluded that, in comparison with the standard anti-HC drug (fluvastatin) used in this study, both cold and hot UFP algalextracts of U. fasciata demonstrated appreciable anti-hypercholesterolemic property, in addition to their antioxidant activity even in the old HC stressed rats. Thus, it could be used as a natural lipid regulator.Keywords: Ulvafasciata, Hypercholesterolemia, Polysaccharides, Rats, Sulfated polysaccharides, Aging, Hyper-cholesterolemia
PHYTOCHEMICAL ANALYSIS, ASSESSMENT OF ANTIPROLIFERATIVE AND FREE RADICAL SCAVENGING ACTIVITY OF MORUS ALBA AND MORUS RUBRA FRUITS
Objective: Mulberry is a nontoxic commonly eaten plant, belongs to the Morus and used in folk medicine in the remedy of dysentery, antiphlogistic, diuretic, expectorant, and antidiabetic. The purpose of this study is to evaluate the antiproliferative and radical scavenging activity of the total alcoholic and successive fractions thereof of Morus alba and Morus rubra fruits. In addition, the chemical composition of the bioactive fractions of each species was investigated.Methods: The antiproliferative potential of 8 extracts on 4 human cancer cell lines, hepatocellular carcinoma (HepG2), Caucasian breast adenocarcinoma (MCF7), prostate (PC3), and colon carcinoma (HCT116) in addition to one normal cell line namely human normal immortalized skin fibroblast cells (BJ1) were carried out. Cell viability was determined using MTT assay. The potency was compared with the reference drug doxorubicin. These extracts were also assayed for 1,1-diphenyl-2-hydrazyl free radical scavenging activities. After saponification of the n-hexane fraction, unsaponifiable matter and fatty acid methyl esters were analyzed by gas liquid chromatography (GLC). The chemical composition of the bioactive fractions was investigated using gas chromatography/mass spectrometry (GC/MS) analysis.Results: All the extracts showed significant free radical scavenging activity dose-dependently. The n-hexane and dichloromethane (DCM) fractions of M. rubra exhibited potent cytotoxic activity on almost cancer cell lines. In the same pattern, ethyl acetate (EtOAc) of M. rubra has moderate cytotoxic activity against all cell lines except HepG2. DCM fraction of M. alba possessed both radical scavenging and high potential antiproliferated activities against HCT116 and MCF7 with inhibitory concentration of 43.9 and 32.3 μg/ml, respectively, while it showed no cytotoxic effect on BJ1. GLC analysis showed the major hydrocarbons in M. alba and M. rubra were heptacosane and docosane, respectively. Sterols were similar in both species but with different ratios and cholesterol was the major one. Palmitic and margaric were the major saturated fatty acid while arachidonic was the major unsaturated fatty acid in both species. GC/MS analysis showed the main compound in DCM fraction of each Morus species was palmitic acid. Furthermore, 1,11-bis-(methoxycarbonyl-ethenyl)-10,2-dihydroxy-cycloeicosane and linolelaidic acid, methyl ester were the main compounds in the EtOAc fraction of each Morus species. Whereas, the main compounds in alcoholic extract of M. alba and M. rubra were methyl-14-methyl-pentadecanoate and 1,2-O-isopropylyidene-4-nonene-1,2,3-triol, respectively.Conclusions: The results observed remarkable biological activity of the successive fractions of M. rubra more than those of M. alba and confirmed its importance as a natural bioactive source. Morus species are good candidates to be promising as possible sources for future antitumor and antioxidants in food and pharmaceutical formulations. The strong activity partly explains the potential effects of Morus species for the treatment of cancer and degenerative diseases caused by free radicals
PHYTOPHENOLICS COMPOSITION, HYPOLIPIDEMIC, HYPOGLYCEMIC AND ANTIOXIDATIVE EFFECTS OF THE LEAVES OF FORTUNELLA JAPONICA (THUNB.) SWINGLE
Objective: Fortunella japonica (Thunb.) Swingle is an evergreen shrub, its whole fruit, including the peel, is eaten. There have been few detailed phytophenolics composition reports on this genus and the hypoglycemic and hypolipidemic effects of the plant were not evaluated. Methods: Structures of the isolated compounds were elucidated by spectral analysis. Serum glucose level, activities of liver enzymes, total protein content, serum lipid profiles, antioxidant parameters and some glycolytic and gluconeogenic enzymes in streptozotocin (STZ)-induced diabetic rats were determined. The evaluation also carried out through determination of liver disorder biomarkers and histopathological examination of liver, kidney and pancreas. Results: Six phytophenolics were isolated, for the first time from the genus Fortunella as well as a sterol compound. Treatment with the ethanolic extract of F. japonica leaves effectively meliorated antioxidant markers and glycolytic enzymes. The histopathological analyzes also confirmed the experimental findings.Conclusion: The results show that the ethanolic extract has hypoglycemic, hypotriglyceridemic and antioxidant effects in STZ-induced diabetic rats, suggesting that this extract supplementation can be useful in preventing diabetic complications associated with hyperlipidemia and oxidative stress.Â
SULPHATED POLYSACCHARIDES (SPS) FROM THE GREEN ALGA ULVA FASCIATA EXTRACT MODULATES LIVER AND KIDNEY FUNCTION IN HIGH FAT DIET-INDUCED HYPERCHOLESTEROLEMIC RATS
Objective: Hypercholesterolemia (HC) was frequently associated with oxidative stress, and release of inflammatory cytokines is to determine the hypolipidemic effects of sulphated polysaccharides from seaweed Ulva fasciata algal extracts through measuring the activities of some parameters related to liver and kidney functions in the serum of hypercholesterolemic rats as compared to normal one.Methods: Different groups of rats were administered a high cholesterol diet. Liver and kidney functions, inflammatory cytokines (TNF-α, CRP, MPO and IL-10), oxidative stress (GSH, MDA and NO), in addition to cell adhesion molecules (ICAM-1 and VCAM-1) were assessed before and after treatment with the algal polysaccharides. In addition, histological examination of liver and kidney were performed to confirm the biochemical findings.Results: The obtained results showed that oxidative stress and inflammatory markers associated with hypercholesterolemia were significantly increased in HC-rats. The histopathological examination of liver and kidney demonstrated severe degeneration with diffuse vacuolar degeneration, necrosis and the presence of fatty droplets. In addition; nephron-histological examination revealed, mild glomerular injury with mild vascular and inflammatory changes. Treatment with the algal sulphated polysaccharides effectively improved these disorders and diminished the formation of fatty liver, as well as renal dysfunction more than the reference drug; fluvastatin. Conclusion: It could be concluded that the consumption of UFP (Ulva fasciata polysaccharides), may be associated with attenuation of inflammatory markers, amelioration of fatty liver and improvement of renal dysfunction, that in turn lead to counteract hypercholesterolemia and its related disorders; such as obesity, and heart disease.Keywords: Non-alcoholic fatty liver disease, Seaweed, Ulva fasciata, Hypercholesterolemia, Hypolipidemic activity, Sulphated polysaccharides (SPs
A new variational approach to the stability of gravitational systems
We consider the three dimensional gravitational Vlasov Poisson system which
describes the mechanical state of a stellar system subject to its own gravity.
A well-known conjecture in astrophysics is that the steady state solutions
which are nonincreasing functions of their microscopic energy are nonlinearly
stable by the flow. This was proved at the linear level by several authors
based on the pioneering work by Antonov in 1961. Since then, standard
variational techniques based on concentration compactness methods as introduced
by P.-L. Lions in 1983 have led to the nonlinear stability of subclasses of
stationary solutions of ground state type.
In this paper, inspired by pioneering works from the physics litterature
(Lynden-Bell 94, Wiechen-Ziegler-Schindler MNRAS 88, Aly MNRAS 89), we use the
monotonicity of the Hamiltonian under generalized symmetric rearrangement
transformations to prove that non increasing steady solutions are local
minimizer of the Hamiltonian under equimeasurable constraints, and extract
compactness from suitable minimizing sequences. This implies the nonlinear
stability of nonincreasing anisotropic steady states under radially symmetric
perturbations
A diagnosis on torque reversals in 4U 1626-67
Several X-ray pulsars have been observed to experience torque reversals,
which provide important observational clues to the interaction between the
neutron star magnetic field and the accretion disk. We review the current
models proposed for the torque reversals and discuss their viability based on
the observations of the quasi-periodic oscillations (QPOs) in 4U 1626-67. Most
of these models seem to be incompatible with the evolution of the QPO
frequencies if they are interpreted in terms of the beat frequency model. We
suggest that winds or outflows from the neutron star and the accretion disk may
play an important role in accounting for the spin-down in disk-fed neutron
stars.Comment: 7 pages, accepted for publication in A&
Incidental congenital coronary artery vascular fistulas in adults:Evaluation with adenosine-N-13-ammonia PET-CT
AIM To assess the functionality of congenital coronary artery fistulas (CAFs) using adenosine stress N-13-ammonia positron emission tomography computed tomography (PET-CT). METHODS Congenital CAFs were incidentally detected during coronary angiography (CAG) procedures in 11 adult patients (six males and five females) with a mean age of 64.3 years (range 41-81). Patients were collected from three institutes in the Netherlands. The characteristics of the fistulas (origin, pathway and termination), multiplicity of the origins and pathways of the fistulous vessels were assessed by CAG. Five patients underwent adenosine pharmacologic stress N-13-ammonia PET-CT to assess myocardial perfusion and the functional behavior of the fistula. RESULTS Eleven patients with 12 CAFs, 10 unilateral and one bilateral, originating from the left anterior descending coronary artery (n = 8), right coronary artery (n = 2) and circumflex (n = 2). All fistulas were of the vascular type, terminating into either the pulmonary artery (n = 11) or coronary sinus (n = 1). The CAG delineated the characteristics of the fistula (origin, pathway and termination). Multiplicity of the origins and pathways of the fistulous vessels were common in most fistulas (8/12, 67% and 9/12, 75%, respectively). Multiplicity was common among the different fistula components (23/36, 64%). Adenosine pharmacologic stress N-13-ammonia PET-CT revealed normal myocardial perfusion and ejection fraction in all but one patient, who showed a reduced ejection fraction. CONCLUSION PET-CT may be helpful for assessing the functional status of congenital CAFs in selected patients regarding clinical decision-making. Studies with a larger patient series are warranted
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