274 research outputs found

    Level Crossing Analysis of the Stock Markets

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    We investigate the average frequency of positive slope να+\nu_{\alpha}^{+}, crossing for the returns of market prices. The method is based on stochastic processes which no scaling feature is explicitly required. Using this method we define new quantity to quantify stage of development and activity of stocks exchange. We compare the Tehran and western stock markets and show that some stocks such as Tehran (TEPIX) and New Zealand (NZX) stocks exchange are emerge, and also TEPIX is a non-active market and financially motivated to absorb capital.Comment: 6 pages and 4 figure

    Protective effect of hydroethanolic extract of cress against hepatotoxicity due to acetaminophen in rats

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    Background and purpose: Acetaminophen is a routine analgesic and antipyretic agent that in overdose causes liver and kidney necrosis in both humans and animals. The cress (Lepidium sativum L.) contains flavonoid, alkaloid, and antioxidant components. In this study we investigated the hepatic protection of the hydroethanolic extract of cress against hepatotoxicity due to acetaminophen. Materials and methods: Forty-two rats were randomly divided into six groups. The first (control) and second (test without treatment) groups were administered the solvent of drug in the morning (08:00) and evening (16:00) on days 1 and 2 but, the third, fourth, and fifth groups received 200, 500, and 1000 mg/kg b.w of the extract of the cress, respectively. The sixth group (positive control) received 200 mg/kg b.w silymarin. Then all groups, except the control group, received 400 mg/kg acetaminophen per os on day 2 (10:00). After 24 hr, all blood samples were collected for determination of GOT (glutamicoxaloacetic transaminase), GPT (glutamic- pyruvic transaminase), ALP (alkaline phosphatase), malondialdehyde (MDA), and serum antioxidant capacity. Also, a piece of liver was used for determining catalase activity and histopathological studies. For statistical analysis of the data, group means were analyzed with one way ANOVA followed by Tukey's test for multiple comparisons. Results: Serum GOT, GPT, ALP, and MDA reduced significantly (P< 0.001) in the treated groups with the extract of cress compared to acetaminophen group without treatment. The reduction of GPT and ALP were dose dependent. The serum antioxidant capacity and liver catalase in treated groups with the extract of the cress and silymarin treated group elevated significantly (P< 0.001) compared to the acetaminophen group without treatment. The liver histopathology in rats treated with the extract of cress showed a remarkable reduction of lymphocyte infiltration compared with rats without treatment (group two). Conclusion: These results demonstrate that the extract of the cress have protection effect against hepatotoxicity due to acetaminophen

    Level Crossing Analysis of Burgers Equation in 1+1 Dimensions

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    We investigate the average frequency of positive slope να+\nu_{\alpha}^{+}, crossing the velocity field u(x)uˉ=αu(x)- \bar u = \alpha in the Burgers equation. The level crossing analysis in the inviscid limit and total number of positive crossing of velocity field before creation of singularities are given. The main goal of this paper is to show that this quantity, να+\nu_{\alpha}^{+}, is a good measure for the fluctuations of velocity fields in the Burgers turbulence.Comment: 5 pages, 3 figure

    Consistency of f(R)=R2R02f(R)=\sqrt{R^{2}-R_{0}^2} Gravity with the Cosmological Observations in Palatini Formalism

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    In this work we study the dynamics of universe in f(R)=R2R02f(R)=\sqrt{R^2-R_{0}^2} modified gravity with Palatini formalism. We use data from recent observations as Supernova Type Ia (SNIa) Gold sample and Supernova Legacy Survey (SNLS) data, size of baryonic acoustic peak from Sloan Digital Sky Survey (SDSS), the position of the acoustic peak from the CMB observations and large scale structure formation (LSS) from the 2dFGRS survey to put constraint on the parameters of the model. To check the consistency of this action, we compare the age of old cosmological objects with the age of universe. In the combined analysis with the all the observations, we find the parameters of model as R0=6.1920.177+0.167×H02R_0=6.192_{-0.177}^{+0.167}\times H_0^2 and Ωm=0.2780.278+0.273\Omega_m=0.278_{-0.278}^{+0.273}.Comment: 12 pages, 7 figure

    Power-law Parameterized Quintessence Model

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    We introduce a power-law parameterized quintessence model for the dark energy which accelerate universe at the low redshifts while behaves as an ordinary matter for the early universe. We construct a unique scalar potential for this parameterized quintessence model. As the observational test, the Supernova Type Ia (SNIa) Gold sample data, size of baryonic acoustic peak from Sloan Digital Sky Survey (SDSS), the position of the acoustic peak from the CMB observations and structure formation from the 2dFGRS survey are used to constrain the parameters of the quintessence model. The best fit parameters indicates that the equation of state of this model at the present time is less than one (w0<1)(w_0<-1) which violates the energy condition in General Relativity. Finally we compare the age of old objects with age of universe in this model.Comment: 11 pages, 17 figures, submitted to Phys. Rev.

    Neurite outgrowth by the alternatively spliced region of human tenascin-C is mediated by neuronal alpha7beta1 integrin

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    The region of tenascin-C containing only alternately spliced fibronectin type-III repeat D (fnD) increases neurite outgrowth by itself and also as part of tenascin-C. We previously localized the active site within fnD to an eight amino acid sequence unique to tenascin-C, VFDNFVLK, and showed that the amino acids FD and FV are required for activity. The purpose of this study was to identify the neuronal receptor that interacts with VFDNFVLK and to investigate the hypothesis that FD and FV are important for receptor binding. Function-blocking antibodies against both alpha7 and beta1 integrin subunits were found to abolish VFDNFVLK-mediated process extension from cerebellar granule neurons. VFDNFVLK but not its mutant, VSPNGSLK, induced clustering of neuronal beta1 integrin immunoreactivity. This strongly implicates FD and FV as important structural elements for receptor activation. Moreover, biochemical experiments revealed an association of the alpha7beta1 integrin with tenascin-C peptides containing the VFDNFVLK sequence but not with peptides with alterations in FD and/or FV. These findings are the first to provide evidence that the alpha7beta1 integrin mediates a response to tenascin-C and the first to demonstrate a functional role for the alpha7beta1 integrin receptor in CNS neurons

    Multifractal analysis of stress time series during ultrathin lubricant film melting

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    Melting of an ultrathin lubricant film confined between two atomically flat surfaces is we studied using the rheological model for viscoelastic matter approximation. Phase diagram with domains, corresponding to sliding, dry, and two types of stickslipstick-slip friction regimes has been built taking into account additive noises of stress, strain, and temperature of the lubricant. The stress time series have been obtained for all regimes of friction using the Stratonovich interpretation. It has been shown that self-similar regime of lubricant melting is observed when intensity of temperature noise is much larger than intensities of strain and stress noises. This regime is defined by homogenous distribution, at which characteristic stress scale is absent. We study stress time series obtained for all friction regimes using multifractal detrended fluctuation analysis. It has been shown that multifractality of these series is caused by different correlations that are present in the system and also by a power-law distribution. Since the power-law distribution is related to small stresses, this case corresponds to self-similar solid-like lubricant.Comment: 22 pages, 10 figures, 41 reference

    Multiscaling behavior of atomic-scale friction

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    The scaling behavior of friction between rough surfaces is a well-known phenomenon. It might be asked whether such a scaling feature also exists for friction at an atomic scale despite the absence of roughness on atomically flat surfaces. Indeed, other types of fluctuations, e.g., thermal and instrumental fluctuations, become appreciable at this length scale and can lead to scaling behavior of the measured atomic-scale friction. We investigate this using the lateral force exerted on the tip of an atomic force microscope (AFM) when the tip is dragged over the clean NaCl (001) surface in ultra-high vacuum at room temperature. Here the focus is on the fluctuations of the lateral force profile rather than its saw-tooth trend; we first eliminate the trend using the singular value decomposition technique and then explore the scaling behavior of the detrended data, which contains only fluctuations, using the multifractal detrended fluctuation analysis. The results demonstrate a scaling behavior for the friction data ranging from 0.2 to 2 nm with the Hurst exponent H = 0.61 +/- 0.02 at a 1 sigma confidence interval. Moreover, the dependence of the generalized Hurst exponent, h(q), on the index variable q confirms the multifractal or multiscaling behavior of the nanofriction data. These results prove that fluctuation of nanofriction empirical data has a multifractal behavior which deviates from white noise

    Interfering effects of in vitro fertilization and vitrification on expression of gtl2 and dlk1 in mouse blastocysts

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    Background: Embryo vitrification is a key instrument in assisted reproductive technologies (ARTs). However, there is increasing concern that vitrification adversely affects embryo development. This study intends to assess the effect of vitrification on developmental competence, in addition to expressions of long non-coding RNA (lncRNA) gene trap locus 2 (Gtl2) and its reciprocal imprinted gene delta-like homolog 1 (Dlk1), in mouse blastocysts. Materials and Methods: In this experimental study, we have designed three experimental groups: control (fresh blas-tocysts collected from superovulated mice), in vitro fertilization (IVF; blastocysts derived from IVF) and vitrification (IVF derived blastocysts subjected to vitrification/warming at the 2-cell stage). Quantitative reverse transcription pol-ymerase chain reaction (qRT-PCR) was performed to assess the expression levels of Gtl2 and Dlk1 in the blastocysts. Results: The results showed that vitrification group had significantly lower blastocyst and hatching rates compared to the IVF group (P<0.037) and (P<0.041), respectively. Gtl2 was down-regulated and Dlk1 was up-regulated following the IVF and vitrification (P<0.05). Conclusion: These results suggested that IVF and vitrification disturbed genomic imprinting and lncRNA gene expres-sions, which might affect the health of IVF children. © 2020, Royan Institute (ACECR). All rights reserved

    Long range correlation in cosmic microwave background radiation

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    We investigate the statistical anisotropy and Gaussianity of temperature fluctuations of Cosmic Microwave Background radiation (CMB) data from {\it Wilkinson Microwave Anisotropy Probe} survey, using the multifractal detrended fluctuation analysis, rescaled range and scaled windowed variance methods. The multifractal detrended fluctuation analysis shows that CMB fluctuations has a long range correlation function with a multifractal behavior. By comparing the shuffled and surrogate series of CMB data, we conclude that the multifractality nature of temperature fluctuation of CMB is mainly due to the long-range correlations and the map is consistent with a Gaussian distribution.Comment: 10 pages, 7 figures, V2: Added comments, references and major correction
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