379 research outputs found

    Anomalous quartic WWγγWW\gamma\gamma couplings in epep collisions at the LHeC and the FCC-he

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    We conducted a study on measuring W+WW^+W^- production and on the sensitivity limits at 95%95\% Confidence Level on thirteen anomalous couplings obtained by dimension-8 operators which are related to the anomalous quartic WWγγWW\gamma\gamma couplings. We consider the main epeγγpeW+Wpe^-p \to e^-\gamma^*\gamma^*p \to e^-W^+W^-p reaction with the sub-process γγW+W\gamma^*\gamma^* \to W^+W^- at the Large Hadron electron Collider (LHeC) and the Future Circular Collider-hadron electron (FCC-he). For the LHeC, energies of the ee^- beams are taken to be Ee=60E_e =60 and 140 GeV and the energy of the pp beams is taken to be Ep=7E_p = 7 TeV. For the FCC-he, energies of the ee^- beams are taken to be Ee=60E_e =60 and 140 GeV and the energy of the pp beams is taken to be Ep=50E_p = 50 TeV, respectively. It is interesting to notice that the LHeC and the FCC-he will lead to model-independent limits on the anomalous quartic WWγγWW\gamma\gamma couplings which are one order of magnitude stringent than the CMS Collaboration limits, in addition to being competitive with other limits reported in the literature.Comment: 28 pages, 10 Figures and 13 Table

    Regulation and competition in the Turkish telecommunications industry: an update

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    This chapter provides an overview of the state of liberalization, competition and regulation of major segments of the telecommunications industry in Turkey. It shows that the competitive stance of the regulatory authority and the development of actual competition has been uneven across segments. Specifically, the degree of competition has been higher in the mobile segment relative to fixed telephony or broadband. The chapter also discusses the new Electronic Communications Law and argues that although not perfect, it provides a coherent basis on which the regulatory authority can pursue competitive objectives in a more even manner. However, the actual development of competition will depend a lot on how the law and the ensuing secondary legislation are actually implemented

    Optical properties of radially-polarised twisted light

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    We show that, in general, any type of radially-polarised paraxial twisted optical mode carries only an axial total optical angular momentum (AM) Jˉz=L0{\bar {\cal J}_z}=\ell{\cal L}_0 where \ell is the winding number and L0{\cal L}_0 is a constant. This mode, however, is shown to have zero spin angular momentum (SAM), so it is endowed only with orbital angular momentum (OAM) and no SAM. The helicity is found to be proportional to \ell, hence radially-polarised modes display chirality. When applied to a Laguerre-Gaussian (LG) mode our treatment leads to a total helicity equal to (/)Q(\ell/|\ell|){\cal Q}, where Q{\cal Q} is the action constant. The factor (/)=±1(\ell/|\ell|)=\pm 1, depends on the sign, not the magnitude of \ell and so the result holds for any radially-polarised LG mode however large the magnitude of its winding number \ell is. The magnitude of the action constant Q{\cal Q} and hence the helicity are diminished for all such LG modes of large beam waist w0w_0.Comment: 4 figure

    Search for the anomalous ZZZZZZ and ZZγZZ\gamma gauge couplings through the process e+eZZe^+e^- \to ZZ with unpolarized and polarized beams

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    This work offers the constraints on the anomalous neutral triple gauge couplings (aNTGC) for the process e+eZZe^+e^- \to ZZ at the CLIC with s=3\sqrt{s}=3 TeV. The realistic CLIC detector environments and their effects are considered in our analysis. The study is planned for the decays of producted ZZ bosons to a pair of charged leptons (electrons or muons) and neutrino pairs. The bounds on the aNTGCs defining CPCP-conserving CB~W/Λ4C_{\widetilde{B}W}/{\Lambda^4} coupling and three CPCP-violating CWW/Λ4C_{WW}/{\Lambda^4}, CBW/Λ4C_{BW}/{\Lambda^4}, and CBB/Λ4C_{BB}/{\Lambda^4} couplings are obtained. Also, the effects and advantages of polarization for incoming electron beams in these calculations are investigated.Comment: 21 pages, 14 figure

    Anticipation via canards in excitable systems

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    Neurons can anticipate incoming signals by exploiting a physiological mechanism that is not well understood. This article offers a novel explanation on how a receiver neuron can predict the sender’s dynamics in a unidirectionally-coupled configuration, in which both sender and receiver follow the evolution of a multi-scale excitable system. We present a novel theoretical viewpoint based on a mathematical object, called canard, to explain anticipation in excitable systems. We provide a numerical approach, which allows to determine the transient effects of canards. To demonstrate the general validity of canard-mediated anticipation in the context of excitable systems, we illustrate our framework in two examples, a multi-scale radio-wave circuit (the van der Pol model) that inspired a caricature neuronal model (the FitzHugh-Nagumo model) and a biophysical neuronal model (a 2-dimensional reduction of the Hodgkin-Huxley model), where canards act as messengers to the senders’ prediction. We also propose an experimental paradigm that would enable experimental neuroscientists to validate our predictions. We conclude with an outlook to possible fascinating research avenues to further unfold the mechanisms underpinning anticipation. We envisage that our approach can be employed by a wider class of excitable systems with appropriate theoretical extensions.ERC Advanced Grant NerVi no. 227747 Ikerbasque (The Basque Foundation for Science

    A comparative study on the antioxidant activity of fringe tree (Chionanthus virginicus L.) extracts

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    Fringe tree (Chionanthus virginicus L.) is used as a raw material by pharmaceutical industries for the preparation of homeopathy tinctures. In this study, antioxidant activity of methanol extract (MEFT) andethylacetate extract (EEFT) from root bark of fringe tree (C. virginicus L.) were evaluated. 2,2-Azinobis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging, 1,1-diphenyl-2-picryl-hydrazyl freeradical (DPPH.) scavenging, superoxide anion (O2 •-) radical scavenging, total antioxidant activity, reducing activity, hydrogen peroxide (H2O2) scavenging and ferrous metal chelating activities were for used antioxidant evaluation of MEFT and EEFT. The both extracts neutralized the activities of radicals and inhibited the peroxidation reactions of linoleic acid emulsion. Total antioxidant activity wasmeasured according to ferric thiocyanate method. Butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), á-tocopherol and trolox, a water-soluble analogue of tocopherol, were used as thereference antioxidant compounds. MEFT and EEFT showed 69.4, 79.3, 72.3 and 83.7% inhibition on lipid peroxidation of linoleic acid emulsion, respectively, at the 10 and 20 ìg/mL concentrations. On the other hand, 20 ìg/mL of á-tocopherol, trolox, BHA and BHT exhibited 54.7, 20.1, 74.4 and 71.2% inhibition on peroxidation of linoleic acid emulsion, respectively. Also, MEFT and EEFT have effective DPPH•, ABTS•+ and superoxide anion radicals scavenging, hydrogen peroxide scavenging, total reducing power and metal chelating on ferrous ions activities

    Study of the projected sensitivity on the anomalous quartic gauge couplings via ZγγZ\gamma\gamma production at the CLIC

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    Gauge boson self-couplings are completely defined by the non-Abelian gauge symmetry of the Standard Model (SM), thus direct search for these couplings are extremely significant in understanding the gauge structure of the SM. The possible deviation from the SM predictions of gauge boson self-couplings would be a sign of the presence of new physics beyond the SM. In this work, we study the sensitivities on the anomalous couplings defined by dimension-8 operators related to the ZZγγZZ\gamma\gamma and ZγγγZ\gamma\gamma\gamma quartic vertices through the process e+eZγγe^+e^- \to Z\gamma\gamma with Z-boson decaying to charged leptons at the Compact Linear Collider (CLIC). We analyze the center-of-mass energy of 3 TeV, integrated luminosities of L=1,4,5{\cal L}=1, 4, 5 ab1\rm ab^{-1}, systematic uncertainties of δsys=0%,5%,10%\delta_{sys}=0\%, 5\%, 10\%, and unpolarized and polarized electron beams for extraction of expected sensitivity on the anomalous fT,j/Λ4f_ {T,j}/\Lambda^4 couplings at 95%95\% confidence level, which are especially sensitive to the ZγγZ\gamma\gamma channel. It is clear from the results that if the systematic error is improved, we expect better limits on the couplings. The best limits obtained on the anomalous quartic couplings for the process e+eZγγe^+e^- \to Z\gamma\gamma with s=3\sqrt{s}= 3 TeV, L=5{\cal L}=5 ab1\rm ab^{-1} and δsys=0%\delta_{sys}=0\% can be approximately improved up to about two times better than the limits obtained with δsys=10%\delta_{sys}=10\%. Our sensitivities on the anomalous quartic couplings with δsys=0%\delta_{sys}=0\% can set more stringent sensitivity by two orders of magnitude concerning the best sensitivity derived from the current experimental limits. Finally, with initial electron beam polarization, the sensitivity of the anomalous quartic couplings improves by almost a factor of 1.2.Comment: 38 pages, 22 figure

    Study on the anomalous quartic W+WγγW^+W^-\gamma\gamma couplings of electroweak bosons in epe^-p collisions at the LHeC and the FCC-he

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    In this paper, a study is carried out on the epeγppW+γνee^-p \to e^-\gamma^* p \to p W^+\gamma \nu_e production to probe quartic W+WγγW^+W^-\gamma\gamma couplings using 10, 100 fb1{\rm fb^{-1}} of epe^-p collisions data at s\sqrt{s}= 1.30, 1.98 GeV at the Large Hadron electron Collider (LHeC) and 100, 1000 fb1{\rm fb^{-1}} with s\sqrt{s}= 3.46, 5.29 GeV at the Future Circular Collider-hadron electron (FCC-he). Production cross-sections are determined for both at leptonic and hadronic decay channel of the WW-boson. With the data from future epe^-p colliders, it is possible to obtain sensitivity measures at 95%95\% C.L. on the anomalous fM,i/Λ4f_ {M,i}/\Lambda^4 and fT,i/Λ4 f_ {T,i}/\Lambda^4 couplings which are competitive with the limits obtained by the LHC, as well as with others limits reported in the literature. The production mode epeγppW+γνee^-p \to e^-\gamma^* p \to p W^+\gamma \nu_e in epe^-p collisions offers a window for study the quartic W+WγγW^+W^-\gamma\gamma electroweak bosons couplings at the LHeC and the FCC-he, which provides a much cleaner collision environment than the LHC.Comment: 27 pages , 10 figure

    Association of the Asn306Ser variant of the SP4 transcription factor and an intronic variant in the β-subunit of transducin with digenic disease

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    Purpose SP4 is a transcription factor abundantly expressed in retina that binds to the GC promoter region of photoreceptor signal transduction genes. We have previously shown that SP4 may be involved in the transcriptional activation of these genes alone or together with other transcription factors such as SP1, neural retina leucine zipper protein (NRL), and cone-rod homeobox gene (CRX). Since mutations in NRL and CRX are involved in inherited retinal degenerations, SP4 was considered a good candidate for mutation screening in patients with this type of diseases. The purpose of this work, therefore, was to investigate possible mutations in SP4 in a cohort of patients affected with different forms of retinal degenerations. Methods 270 unrelated probands with various forms of retinal degeneration including autosomal dominant and autosomal recessive retinitis pigmentosa (RP), autosomal dominant and autosomal recessive cone-rod dystrophy (CRD), and Leber's congenital amaurosis (LCA), were screened for mutations in the SP4 gene. Single strand conformation polymorphism (SSCP) analysis was performed on the six SP4 gene exons including flanking regions followed by direct sequencing of SSCP variants. Results Nine different sequence variants were found in 29 patients, four in introns and five in exons. Many of the probands were previously screened for mutations in the genes encoding the α-, β- and γ-subunits of rod-specific cGMP phosphodiesterase (PDE6A, PDE6B, PDE6G), the β-subunit of rod-specific transducin (GNB1), and peripherin/rds (RDS). One group of seven probands of Hispanic background that included five with arRP, one with RP of unknown inheritance (isolate) and 1 with arCRD carried an Asn306Ser mutation in SP4. Of the seven, the isolate case was homozygous and the other 6 heterozygous for the variant. Two arRP and the arCRD probands carried an additional intronic GNB1 variant. DNA from the family members of the arCRD proband could not be obtained, but for the other two families, all affected members and none of the unaffected carried both the SP4 Asn306Ser allele and the GNB1 intronic variant. Conclusions If mutations in SP4 do cause retinal degenerative disease, their frequency would be low. While digenic disease with the SP4 Asn306Ser and the GNB1 intronic variant alleles has not been established, neither has it been ruled out. This leaves open the possibility of a cooperative involvement of SP4 and GNB1 in the normal function of the retina.PubMedWo
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