Synchronization and multi-mode dynamics of mutually coupled semiconductor lasers

Dynamics of coupled semiconductor lasers is investigated by numerical simulations. A realistic laser simulation engine is used to study the synchronization and dynamical regime in two mutually coupled Fabry-Perot and/or DFB lasers. Both, single- and multi-mode operation regimes are studied with emphasis on the role of the multiple laser-cavity modes. Our findings indicate that the two laser synchronize within each laser-cavity mode, while the synchronization across different cavity modes is significantly weaker

COVID-19 raises a health and human rights imperative to advance a UN Convention on the Rights of Older Persons

The COVID-19 pandemic has revealed the inequitable health harms and human rights violations faced by older persons, raising a need to support healthy ageing policy as a human rights imperative. However, international human rights law has long neglected the health-related human rights of older persons. Drawing from evolving advocacy efforts to advance the rights of older persons through the United Nations (UN), tentative initial steps have been taken at the regional level, with states in the Americas codifying intersectional rights obligations underlying health through the Inter-American Convention on Protecting the Human Rights of Older Persons. These international and regional efforts provide a foundation to advance the right to health for older persons. Amid an ongoing demographic transition and an inequitable pandemic response, the prospective UN Convention on the Rights of Older Persons provides a crucial opportunity to elaborate and uphold the international legal obligations necessary to facilitate healthy ageing

Charge-Stripe Order and Superconductivity in Ir1−xPtxTe2\mathrm{Ir_{1-x}Pt_xTe_2}

A combined resistivity and hard x-ray diffraction study of superconductivity and charge ordering in $\mathrm{Ir_{1-x}Pt_xTe_2}$, as a function of Pt substitution and externally applied hydrostatic pressure, is presented. Experiments are focused on samples near the critical composition $x_c\sim 0.045$ where competition and switching between charge order and superconductivity is established. We show that charge order as a function of pressure in $\mathrm{Ir_{0.95}Pt_{0.05}Te_{2}}$ is preempted - and hence triggered - by a structural transition. Charge ordering appears uniaxially along the short crystallographic (1,0,1) domain axis with a $\mathrm{(\frac{1}{5},0,\frac{1}{5})}$ modulation. Based on these results we draw a charge-order phase diagram and discuss the relation between stripe ordering and superconductivity.Comment: 8 pages, 4 figures: Accepted in Scientific Report

The N-methyl-d-aspartate receptor antagonist CPP alters synapse and spine structure and impairs long-term potentiation and long-term depression induced morphological plasticity in dentate gyrus of the awake rat

Long-term morphological synaptic changes associated with homosynaptic long-term potentiation (LTP) and heterosynaptic long-term depression (LTD) in vivo, in awake adult rats were analyzed using three-dimensional (3-D) reconstructions of electron microscope images of ultrathin serial sections from the molecular layer of the dentate gyrus. For the first time in morphological studies, the specificity of the effects of LTP and LTD on both spine and synapse ultrastructure was determined using an N-methyl-d-aspartate (NMDA) receptor antagonist CPP (3-[(R)-2-carboxypiperazin-4-yl]-propyl-1-phosphonic acid). There were no differences in synaptic density 24 h after LTP or LTD induction, and CPP alone had no effect on synaptic density. LTP increased significantly the proportion of mushroom spines, whereas LTD increased the proportion of thin spines, and both LTP and LTD decreased stubby spine number. Both LTP and LTD increased significantly spine head evaginations (spinules) into synaptic boutons and CPP blocked these changes. Synaptic boutons were smaller after LTD, indicating a pre-synaptic effect. Interestingly, CPP alone decreased bouton and mushroom spine volumes, as well as post-synaptic density (PSD) volume of mushroom spines.These data show similarities, but also some clear differences, between the effects of LTP and LTD on spine and synaptic morphology. Although CPP blocks both LTP and LTD, and impairs most morphological changes in spines and synapses, CPP alone was shown to exert effects on aspects of spine and synaptic structure

Conjugation problem about jointly separate flow of viscoelastic and viscous fluids in the plane duct

Conjugation problem about jointly separate flow of viscoelastic and viscous fluids in the plane duct is considered. The results concerning of solvability of this problem are presented. The implicit difference scheme for the conjugation problem is constructed. The consistency conditions are approximated with the second order of approximation with respect to spatial variable. The convergence of the suggested difference scheme is investigated by method of energy inequalities. Sujungimo uždavinys, aprašantis bendrą klampaus ir klampiaielastingo skysčių tekėjimą plokščiuose kanaluose Santrauka Nagrinejamos sujungimo salygos, kai liečiasi klampus ir klampiaielastingas skysčiai. Ištirtas diferencialinio uždavinio išsprendžiamumas. Uždavinys aproksimuojamas neišreikštine baigtiniu skirtumu schema. Suderinamumo salygos aproksimuojamos antrosios tikslumo eiles diskrečiuoju analogu. Energetiniu nelygybiu metodu irodomas baigtiniu skirtumu schemos sprendinio konvergavimas ir ivertinamas konvergavimo greitis. First Published Online: 14 Oct 201

The estimates of accuracy of difference schemes for the nonlinear heat equation with weak solution

In this paper we study the convergence of explicit and implicit finite difference scheme for the first initial‐boundary value problem for one dimensional quasilinear heat‐conduction equation with “unbounded nonlinearity”. Baigtinių skirtumų schemų, aproksimuojančių silpnuosius netiesinės šilumos lygties sprendinius, tikslumo įverčiai Santrauka Nagrinejami vienmates netiesines šilumos laidumo lygties skaitiniai sprendimo metodai, kai lygtis turi tik silpnaji sprendini. Lygties koeficientai yra stipriai netiesiniai. Ištirtos išreikštine ir neišreikštine baigtiniu skirtumu schemos. Aproksimuojant funkcijas panaudoti Steklovo vidurkinimo operatoriai. Gautieji paklaidu iverčiai yra suderinti su diferencialinio uždavinio sprendinio glodumu. First Published Online: 14 Oct 201

Multi-length scale 5D diffraction imaging of Ni-Pd/CeO2-ZrO2/Al2O3 catalyst during partial oxidation of methane

A 5D diffraction imaging experiment (with 3D spatial, 1D time/imposed operating conditions and 1D scattering signal) was performed with a Ni–Pd/CeO2–ZrO2/Al2O3 catalyst. The catalyst was investigated during both activation and partial oxidation of methane (POX). The spatio-temporal resolved diffraction data allowed us to obtain unprecedented insight into the behaviour and fate of the various metal and metal oxide species and how this is affected by the heterogeneity across catalyst particles. We show firstly, how Pd promotion although facilitating Ni reduction, over time leads to formation of unstable Ni–Pd metallic alloy, rendering the impact of Pd beyond the initial reduction less important. Furthermore, in the core of the particles, where the metallic Ni is primarily supported on Al2O3, poor resistance towards coke deposition was observed. We identified that this preceded via the formation of an active yet metastable interstitial solid solution of Ni–C and led to the exclusive formation of graphitic carbon, the only polymorph of coke observed. In contrast, at the outermost part of the catalyst particle, where Ni is predominantly supported on CeO2–ZrO2, the graphite formation was mitigated but sintering of Ni crystallites was more severe

Relación entre el bienestar y el rendimiento académico en alumnos de primer año de medicina

Background: Stress may affect the sense of wellbeing and academic achievement of university students. Aim: To assess the relationship of academic engagement and burnout with academic achievement among first year medical students. Material and Methods: The Utrecht Work Engagement Scale-Student and Maslach Burnout Inventory Student Survey (MBI-SS) were applied to 277 first year medical students of four universities. Their results were correlated with the grades obtained in the different courses. Results: Moderately high engagement and low burnout levels were detected. There was a high level of satisfaction with studies and a moderate exhaustion level. Academic achievement was associated with the degree of engagement with studies but not with burnout. Conglomerate analysis detected a group of students with high levels of wellbeing, characterized by high levels of academic engagement and low burnout. Other group had moderate levels of engagement and lack of personal fulfilment. Other group, identified as extenuated, had high levels of personal exhaustion and depersonalization. Finally the disassociated group had a low academic engagement, low emotional exhaustion, high levels of depersonalization and lack of personal fulfillment. Conclusions: Academic achievement is associated with the level of engagement with studies but not with burnout

Vibrational spectra of C60C8H8 and C70C8H8 in the rotor-stator and polymer phases

C60-C8H8 and C70-C8H8 are prototypes of rotor-stator cocrystals. We present infrared and Raman spectra of these materials and show how the rotor-stator nature is reflected in their vibrational properties. We measured the vibrational spectra of the polymer phases poly(C60C8H8) and poly(C70C8H8) resulting from a solid state reaction occurring on heating. Based on the spectra we propose a connection pattern for the fullerene in poly(C60C8H8), where the symmetry of the C60 is D2h. On illuminating the C60-C8H8 cocrystal with green or blue light a photochemical reaction was observed leading to a similar product to that of the thermal polymerization.Comment: 26 pages, 8 figures, to appear in Journal of Physical Chemistry B 2nd version: minor changes in wording, accepted version by journa

Коэффициентная устойчивость решений разностных схем, аппроксимирующих смешанные задачи для полулинейных гиперболических уравнений

The stability with respect to coefficients of solution of a difference scheme approximating the initial boundary-value problem for the one-dimensional semi-linear hyperbolic equation is studied. The estimates of the solutions of both differential and difference problems are obtained. In the domain of existence of the solution, the estimates for perturbation of the solution of a difference scheme with respect to perturbation of the coefficients of the equation are obtained. These estimates are consistent with the estimates for the differential problem. In all cases, the method of energy inequalities, the Bihari inequality and its mesh analogue are used.Исследуется коэффициентная устойчивость решения разностной схемы, аппроксимирующей смешанную задачу для одномерного полулинейного гиперболического уравнения. Получены оценки решения дифференциальной и разностной задач. При этом решение может разрушаться за конечное время. Установлена нижняя граница разрушения решения. В области существования решения получены оценки возмущения решения разностной схемы по отношению к возмущению коэффициентов уравнения, согласующиеся с оценками для дифференциальной задачи. Во всех случаях применялись метод энергетических неравенств, неравенство Бихари и его сеточный аналог