133 research outputs found

    Spectral Analysis of Multi-dimensional Self-similar Markov Processes

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    In this paper we consider a discrete scale invariant (DSI) process {X(t),tR+}\{X(t), t\in {\bf R^+}\} with scale l>1l>1. We consider to have some fix number of observations in every scale, say TT, and to get our samples at discrete points αk,kW\alpha^k, k\in {\bf W} where α\alpha is obtained by the equality l=αTl=\alpha^T and W={0,1,...}{\bf W}=\{0, 1,...\}. So we provide a discrete time scale invariant (DT-SI) process X()X(\cdot) with parameter space {αk,kW}\{\alpha^k, k\in {\bf W}\}. We find the spectral representation of the covariance function of such DT-SI process. By providing harmonic like representation of multi-dimensional self-similar processes, spectral density function of them are presented. We assume that the process {X(t),tR+}\{X(t), t\in {\bf R^+}\} is also Markov in the wide sense and provide a discrete time scale invariant Markov (DT-SIM) process with the above scheme of sampling. We present an example of DT-SIM process, simple Brownian motion, by the above sampling scheme and verify our results. Finally we find the spectral density matrix of such DT-SIM process and show that its associated TT-dimensional self-similar Markov process is fully specified by {RjH(1),RjH(0),j=0,1,...,T1}\{R_{j}^H(1),R_{j}^H(0),j=0, 1,..., T-1\} where RjH(τ)R_j^H(\tau) is the covariance function of jjth and (j+τ)(j+\tau)th observations of the process.Comment: 16 page

    The Persian developmental sentence scoring as a clinical measure of morphosyntax in children

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    Background: Developmental Sentence Scoring (DSS) was developed as a numerical measurement and a clinical method based on the morphosyntactic acquisition in the English language. The aim of this study was to develop a new numerical tool similar to DSS to assess the morphosyntactic abilities in Persian-speaking children. Methods: In this cross-sectional and comparative study, the language samples of 115 typically developing Persian-speaking children aged 30 - 65 months were audio recorded during the free play and picture description sessions. The Persian Developmental Sentence Score (PDSS) and the Mean Length of Utterance (MLU) were calculated. Pearson correlation and one - way Analysis of variance (ANOVA) were used for data analysis. Results: The correlation between PDSS and MLU in morphemes (convergent validity) was significant with a correlation coefficient of 0.97 (p < 0.001). The value Cronbach's Alpha (α= 0.79) in the grammatical categories and the split-half coefficient (0.86) indicated acceptable internal consistency reliability. Conclusion: The PDSS could be used as a reliable numerical measurement to estimate the syntactic development in Persian-speaking children

    Lateral Spin Valve Based on the Two-Dimensional CrN/P/CrN Heterostructure

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    We propose a spin valve based on a blue-phosphorus monolayer sandwiched between two half-metallic two-dimensional CrN layers. We use density-functional theory combined with Boltzmann transport theory to investigate both the structural and the magnetic stability of the CrN/P/CrN heterostructure and to study its spin-dependent transport properties. Among the different possible layer stackings considered, only one is shown to be thermodynamically stable, corresponding to the AA stacking. In this geometry, the critical temperature of magnetic ordering is estimated to be around 150 K. The electronic structure of CrN/P/CrN is strongly dependent on the mutual orientation of the magnetic moments in individual CrN layers. If the alignment is parallel, only one spin channel predominantly contributes to the electronic bands in the vicinity of the Fermi energy. In the case of an antiparallel alignment, both spin channels contribute to the electronic states. The alteration of magnetic moments affects electronic transport, causing magnetoresistance of up to 12% at moderate dopings. © 2019 American Physical Society.The authors acknowledge Ankara University for use of the high-performance computing facility through the AYP under Grant No. 17A0443001. A.N.R. acknowledges support from the FLAG-ERA JTC2017 Project “Gransport”

    From embodiment to metaphor: A study on social cognitive development and conceptual metaphor in Persian-speaking children

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    This study explores the metaphoric comprehension of normal Persian-speaking children, as well as theories of cognitive development and cultural and social impacts. The researchers discuss the improvement of the understanding of ontological conceptual metaphors through age growth and cognitive development, and how it helps to expand children�s thoughts and knowledge of the world. In this study, 121 normal native Persian-speaking children from the age of 5 to 13 with no language and cognitive disorders participated. Pearson correlation and one-way ANOVA were used to examine the relationships between pairs of variables. The results showed that children start to comprehend abstract concepts and primary ontological metaphors at about 5 years of age, which is in contrast with what Piaget has implied. Children�s metaphorical comprehension improved progressively with age, social, and cognitive development as other studies have also implied, and they understood more complex types of metaphors by age growth. © 2020 IJSCL. All rights reserved

    RNA activation of haploinsufficient Foxg1 gene in murine neocortex

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    More than one hundred distinct gene hemizygosities are specifically linked to epilepsy, mental retardation, autism, schizophrenia and neuro-degeneration. Radical repair of these gene deficits via genome engineering is hardly feasible. The same applies to therapeutic stimulation of the spared allele by artificial transactivators. Small activating RNAs (saRNAs) offer an alternative, appealing approach. As a proof-of-principle, here we tested this approach on the Rett syndrome-linked, haploinsufficient, Foxg1 brain patterning gene. We selected a set of artificial small activating RNAs (saRNAs) upregulating it in neocortical precursors and their derivatives. Expression of these effectors achieved a robust biological outcome. saRNA-driven activation (RNAa) was limited to neural cells which normally express Foxg1 and did not hide endogenous gene tuning. saRNAs recognized target chromatin through a ncRNA stemming from it. Gene upregulation required Ago1 and was associated to RNApolII enrichment throughout the Foxg1 locus. Finally, saRNA delivery to murine neonatal brain replicated Foxg1-RNAa in vivo

    Cell-specific deletion of C1qa identifies microglia as the dominant source of C1q in mouse brain

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    BACKGROUND: The complement cascade not only provides protection from infection but can also mediate destructive inflammation. Complement is also involved in elimination of neuronal synapses which is essential for proper development, but can be detrimental during aging and disease. C1q, required for several of these complement-mediated activities, is present in the neuropil, microglia, and a subset of interneurons in the brain. METHODS: To identify the source(s) of C1q in the brain, the C1qa gene was selectively inactivated in the microglia or Thy-1(+) neurons in both wild type mice and a mouse model of Alzheimer’s disease (AD), and C1q synthesis assessed by immunohistochemistry, QPCR, and western blot analysis. RESULTS: While C1q expression in the brain was unaffected after inactivation of C1qa in Thy-1(+) neurons, the brains of C1qa (FL/FL) :Cx3cr1 (CreERT2) mice in which C1qa was ablated in microglia were devoid of C1q with the exception of limited C1q in subsets of interneurons. Surprisingly, this loss of C1q occurred even in the absence of tamoxifen by 1 month of age, demonstrating that Cre activity is tamoxifen-independent in microglia in Cx3cr1 (CreERT2/WganJ) mice. C1q expression in C1qa (FL/FL) : Cx3cr1 (CreERT2/WganJ) mice continued to decline and remained almost completely absent through aging and in AD model mice. No difference in C1q was detected in the liver or kidney from C1qa (FL/FL) : Cx3cr1 (CreERT2/WganJ) mice relative to controls, and C1qa (FL/FL) : Cx3cr1 (CreERT2/WganJ) mice had minimal, if any, reduction in plasma C1q. CONCLUSIONS: Thus, microglia, but not neurons or peripheral sources, are the dominant source of C1q in the brain. While demonstrating that the Cx3cr1 (CreERT2/WganJ) deleter cannot be used for adult-induced deletion of genes in microglia, the model described here enables further investigation of physiological roles of C1q in the brain and identification of therapeutic targets for the selective control of complement-mediated activities contributing to neurodegenerative disorders. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12974-017-0814-9) contains supplementary material, which is available to authorized users

    Evidence for natural antisense transcript-mediated inhibition of microRNA function

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    MicroRNAs (miRNAs) have the potential to regulate diverse sets of mRNA targets. In addition, mammalian genomes contain numerous natural antisense transcripts, most of which appear to be non-protein-coding RNAs (ncRNAs). We have recently identified and characterized a highly conserved non-coding antisense transcript for beta-secretase-1 (BACE1), a critical enzyme in Alzheimer's disease pathophysiology. The BACE1-antisense transcript is markedly up-regulated in brain samples from Alzheimer's disease patients and promotes the stability of the (sense) BACE1 transcript. We report here that BACE1-antisense prevents miRNA-induced repression of BACE1 mRNA by masking the binding site for miR-485-5p. Indeed, miR-485-5p and BACE1-antisense compete for binding within the same region in the open reading frame of the BACE1 mRNA. We observed opposing effects of BACE1-antisense and miR-485-5p on BACE1 protein in vitro and showed that Locked Nucleic Acid-antimiR mediated knockdown of miR-485-5p as well as BACE1-antisense over-expression can prevent the miRNA-induced BACE1 suppression. We found that the expression of BACE1-antisense as well as miR-485-5p are dysregulated in RNA samples from Alzheimer's disease subjects compared to control individuals. Our data demonstrate an interface between two distinct groups of regulatory RNAs in the computation of BACE1 gene expression. Moreover, bioinformatics analyses revealed a theoretical basis for many other potential interactions between natural antisense transcripts and miRNAs at the binding sites of the latter

    Effective mechanical properties of multilayer nano-heterostructures

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    Two-dimensional and quasi-two-dimensional materials are important nanostructures because of their exciting electronic, optical, thermal, chemical and mechanical properties. However, a single-layer nanomaterial may not possess a particular property adequately, or multiple desired properties simultaneously. Recently a new trend has emerged to develop nano-heterostructures by assembling multiple monolayers of different nanostructures to achieve various tunable desired properties simultaneously. For example, transition metal dichalcogenides such as MoS2 show promising electronic and piezoelectric properties, but their low mechanical strength is a constraint for practical applications. This barrier can be mitigated by considering graphene-MoS2 heterostructure, as graphene possesses strong mechanical properties. We have developed efficient closed-form expressions for the equivalent elastic properties of such multi-layer hexagonal nano-hetrostructures. Based on these physics-based analytical formulae, mechanical properties are investigated for different heterostructures such as graphene-MoS2, graphene-hBN, graphene-stanene and stanene-MoS2. The proposed formulae will enable efficient characterization of mechanical properties in developing a wide range of application-specific nano-heterostructures
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