333 research outputs found

    Neutrino oscillation in a space-time with torsion

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    Using the Einstein-Cartan-Dirac theory, we study the effect of torsion on neutrino oscillation. We see that torsion cannot induce neutrino oscillation, but affects it whenever oscillation exists for other reasons. We show that the torsion effect on neutrino oscillation is as important as the neutrino mass effect, whenever the ratio of neutrino number density to neutrino energy is 1069\sim 10^{69} cm3^{-3} /eV, or the number density of the matter is 1069\sim 10^{69} cm3^{-3}.Comment: 7 pages, LaTex,Some typos corrected Journal: Int. J. Mod. Phys. A (1999) (will be appeared

    Risk factors and consequent outcomes of placenta previa: Report from a referral center

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    Because of an unknown factor, the frequency of complicated pregnancy with placenta previa has been raised during past decade. This study was designed to deepen our understanding of risk factors and outcomes of placenta previa in our country. This study investigated 694 cases of placenta previa comparing with 600 healthy pregnant women with not overlie placenta in two referral and tertiary Obstetrics and Gynecological Hospital in Iran on the basis of the clinical and para-clinical analysis, in order to find the probable risk factors for occurrence of placenta previa and its effect on maternal and neonatal complications. The most important risk factor for the occurrence of placenta previa was advanced maternal age (P<0.001) and history of stillbirth (OR=117.2, CI=58.3-236.0). In the other hand, the most substantial outcome of this disorder was a reduction of gestational age (P<0.001) and low birth weight neonatally (P<0.001). The conservative follow-up should be programmed for women with placenta previa based on the type of risk factors which can provide the best possible management to decrease the morbidity and mortality of their related complications. © 2016 Tehran University of Medical Sciences. All rights reserved

    Demonstration of latency-aware 5G network slicing on optical metro networks

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    Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, los autores pertenecientes a la UAM y el nombre del grupo de colaboración, si lo hubiereThe H2020 METRO-HAUL European project has architected a latency-aware, cost-effective, agile, and programmable optical metro network. This includes the design of semidisaggregated metro nodes with compute and storage capabilities, which interface effectively with both 5G access and multi-Tbit/s elastic optical networks in the core. In this paper, we report the automated deployment of 5G services, in particular, a public safety video surveillance use case employing low-latency object detection and tracking using on-camera and on-the-edge analytics. The demonstration features flexible deployment of network slice instances, implemented in terms of European Telecommunications Standards Institute (ETSI) network function virtualization network services. We summarize the key findings in a detailed analysis of end-to-end quality of service, service setup time, and soft-failure detection time. The results show that the round-trip time over an 80 km link is under 800 µs and the service deployment time is under 180 s.This work has been partially supported by the European Commission (METRO-HAUL GA 761727)

    Angiotensin II Evokes Angiogenic Signals within Skeletal Muscle through Co-ordinated Effects on Skeletal Myocytes and Endothelial Cells

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    Skeletal muscle overload induces the expression of angiogenic factors such as vascular endothelial growth factor (VEGF) and matrix metalloproteinase (MMP)-2, leading to new capillary growth. We found that the overload-induced increase in angiogenesis, as well as increases in VEGF, MMP-2 and MT1-MMP transcripts were abrogated in muscle VEGF KO mice, highlighting the critical role of myocyte-derived VEGF in controlling this process. The upstream mediators that contribute to overload-induced expression of VEGF have yet to be ascertained. We found that muscle overload increased angiotensinogen expression, a precursor of angiotensin (Ang) II, and that Ang II signaling played an important role in basal VEGF production in C2C12 cells. Furthermore, matrix-bound VEGF released from myoblasts induced the activation of endothelial cells, as evidenced by elevated endothelial cell phospho-p38 levels. We also found that exogenous Ang II elevates VEGF expression, as well as MMP-2 transcript levels in C2C12 myotubes. Interestingly, these responses also were observed in skeletal muscle endothelial cells in response to Ang II treatment, indicating that these cells also can respond directly to the stimulus. The involvement of Ang II in muscle overload-induced angiogenesis was assessed. We found that blockade of AT1R-dependent Ang II signaling using losartan did not attenuate capillary growth. Surprisingly, increased levels of VEGF protein were detected in overloaded muscle from losartan-treated rats. Similarly, we observed elevated VEGF production in cultured endothelial cells treated with losartan alone or in combination with Ang II. These studies conclusively establish the requirement for muscle derived VEGF in overload-induced angiogenesis and highlight a role for Ang II in basal VEGF production in skeletal muscle. However, while Ang II signaling is activated following overload and plays a role in muscle VEGF production, inhibition of this pathway is not sufficient to halt overload-induced angiogenesis, indicating that AT1-independent signals maintain VEGF production in losartan-treated muscle

    Tensor Operators for Uh(sl(2))

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    Tensor operators for the Jordanian quantum algebra Uh(sl(2)) are considered. Some explicit examples of them, which are obtained in the boson or fermion realization, are given and their properties are studied. It is also shown that the Wigner-Eckart's theorem can be extended to Uh(sl(2)).Comment: 11pages, LaTeX, to be published in J. Phys.

    Frequency of coexistent eye diseases and cognitive impairment or dementia: a systematic review and meta-analysis

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    Objective: We aim to quantify the co-existence of age-related macular degeneration (AMD), glaucoma, or diabetic retinopathy (DR) and cognitive impairment or dementia. Method: MEDLINE, EMBASE, PsycINFO and CINAHL were searched (to June 2020). Observational studies reporting incidence or prevalence of AMD, glaucoma, or DR in people with cognitive impairment or dementia, and of cognitive impairment or dementia among people with AMD, glaucoma, or DR were included. Results: Fifty-six studies (57 reports) were included but marked by heterogeneities in the diagnostic criteria or definitions of the diseases, study design, and case mix. Few studies reported on the incidence. Evidence was sparse but consistent in individuals with mild cognitive impairment where 7.7% glaucoma prevalence was observed. Prevalence of AMD and DR among people with cognitive impairment ranged from 3.9% to 9.4% and from 11.4% to 70.1%, respectively. Prevalence of AMD and glaucoma among people with dementia ranged from 1.4 to 53% and from 0.2% to 25.9%, respectively. Prevalence of DR among people with dementia was 11%. Prevalence of cognitive impairment in people with AMD, glaucoma, and DR ranged from 8.4% to 52.4%, 12.3% to 90.2%, and 3.9% to 77.8%, respectively, and prevalence of dementia in people with AMD, glaucoma and DR ranged from 9.9% to 62.6%, 2.5% to 3.3% and was 12.5%, respectively. Conclusions: Frequency of comorbid eye disease and cognitive impairment or dementia varied considerably. While more population-based estimations of the co-existence are needed, interdisciplinary collaboration might be helpful in the management of these conditions to meet healthcare needs of an ageing population. Trial registration: PROSPERO registration: CRD42020189484

    Boson representations, non-standard quantum algebras and contractions

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    A Gelfan'd--Dyson mapping is used to generate a one-boson realization for the non-standard quantum deformation of sl(2,R)sl(2,\R) which directly provides its infinite and finite dimensional irreducible representations. Tensor product decompositions are worked out for some examples. Relations between contraction methods and boson realizations are also explored in several contexts. So, a class of two-boson representations for the non-standard deformation of sl(2,R)sl(2,\R) is introduced and contracted to the non-standard quantum (1+1) Poincar\'e representations. Likewise, a quantum extended Hopf sl(2,R)sl(2,\R) algebra is constructed and the Jordanian qq-oscillator algebra representations are obtained from it by means of another contraction procedure.Comment: 21 pages, LaTeX; two new references adde

    (1+1) Schrodinger Lie bialgebras and their Poisson-Lie groups

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    All Lie bialgebra structures for the (1+1)-dimensional centrally extended Schrodinger algebra are explicitly derived and proved to be of the coboundary type. Therefore, since all of them come from a classical r-matrix, the complete family of Schrodinger Poisson-Lie groups can be deduced by means of the Sklyanin bracket. All possible embeddings of the harmonic oscillator, extended Galilei and gl(2) Lie bialgebras within the Schrodinger classification are studied. As an application, new quantum (Hopf algebra) deformations of the Schrodinger algebra, including their corresponding quantum universal R-matrices, are constructed.Comment: 25 pages, LaTeX. Possible applications in relation with integrable systems are pointed; new references adde

    Atomic contributions to the valence band photoelectron spectra of metal-free, iron and manganese phthalocyanines

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    The present work reports a photoelectron spectroscopy study of the low-energy region of the valence band of metal-free phthalocyanine (H2Pc) compared with those of iron phthalocyanine (FePc) and manganese phthalocyanine (MnPc). Density Functional Theory calculations have been used to resolve the atomic orbital composition of the valence spectra of all the phthalocyanines (Pcs) analyzed in this study. Moreover we show how the atomic character of the Highest Occupied Molecular Orbital (HOMO) is reflected on the outermost valence band binding energy region. The intensity related to the C 2p contributions, resulting in the HOMO for H2Pc and FePc and in the HOMO-1 for MnPc as described by the theoretical predictions is in very good agreement with the experimental results. The DFT simulations, discerning the atomic contribution to the density of states, indicate how the central metal atom interacts with the C and N atoms of the molecule, giving rise to different partial and total density of states for these three different Pc molecules
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