Symmetron with a non-minimal kinetic term

We investigate the compatibility of the Symmetron with dark energy by introducing a non-minimal kinetic term associated with the Symmetron. In this new model, the effect of the friction term appearing in the equation of motion of the Symmetron field becomes more pronounced due to the non-minimal kinetic term appearing in the action and, under specific conditions after symmetry breaking, the universe experiences an accelerating phase which, in spite of the large effective mass of the scalar field, lasts as long as the Hubble time $H_{0}$.Comment: 12 pages, 4 figures, to appear in JCA

Thermodynamics second law and ω=−1\omega=-1 crossing(s) in interacting holographic dark energy model

By the assumption that the thermodynamics second law is valid, we study the possibility of $\omega=-1$ crossing in interacting holographic dark energy model. Depending on the choice of the horizon and the interaction, the transition from quintessence to phantom regime and subsequently from phantom to quintessence phase may be possible. The second transition avoids the big rip singularity. We compute the dark energy density at transition time and show that by choosing appropriate parameters we can alleviate the coincidence problem.Comment: 13 pages, 1 figure, a shorter version to appear in Phys. Lett.

Effects of layer thickness on orientation distribution and magnetic properties of CoCrTa/Cr films

Evolution of orientation distribution of Co(110) crystal planes was determined by x-ray rocking curves. It has been found that: (i) The full-width at half maximum W of the Co(110) rocking curve decreases with both increasing Cr underlayer thickness dcr, and increasing CoCrTa magnetic layer thickness dco, especially in the thin layer regime. (ii) For the thin dcoregime, the interlayer diffusion between the Cr underlayer and the magnetic layer affects the rocking curves and magnetic properties significantly. (iii) Film magnetic properties, e.g., a significant jump in coercivity with increasing magnetic layer thickness in the thin dco regime may be related in part to the evolution of the Co(110) orientation distribution

The Association between Presence of Comorbidities and COVID-19 Severity: A Systematic Review and Meta-Analysis

Aim: Several studies reported the accompaniment of severe COVID-19 with comorbidities. However, there is not a systematic evaluation of all aspects of this association. Therefore, this meta-analysis aimed to assess the association between all underlying comorbidities in COVID-19 infection severity. Methods: Electronic literature search was performed via scientific search engines. After the removal of duplicates and selection of articles of interest, 28 studies were included. A fixed-effects model was used; however, if heterogeneity was high (I2 > 50) a random-effects model was applied to combine the data. Results: A total of 6,270 individuals were assessed (1,615 severe and 4,655 non-severe patients). The median age was 63 (95 confidence interval CI: 49-74) and 47 (95% CI: 19-63) years in the severe and non-severe groups, respectively. Moreover, about 41% of patients had comorbidities. Severity was higher in patients with a history of cerebrovascular disease: OR 4.85 (95% CI: 3.11-7.57). The odds of being in a severe group increase by 4.81 (95% CI: 3.43-6.74) for a history of cardiovascular disease (CVD). This was 4.19 (95% CI: 2.84-6.19) for chronic lung disease and 3.18, 95% CI: 2.09-4.82 for cancer. The odds ratios of diabetes and hypertension were 2.61 (95% CI: 2.02-3.3) and 2.37 (95% CI: 1.80-3.13), respectively. Conclusions: The presence of comorbidities is associated with severity of COVID-19 infection. The strongest association was observed for cerebrovascular disease, followed by CVD, chronic lung disease, cancer, diabetes, and hypertension. © 2021 S. Karger AG, Basel. All rights reserved