On the Schwarzschild-de Sitter metric of nonlocal de Sitter gravity

Earlier constructed a simple nonlocal de Sitter gravity model has a cosmological solution in a very good agreement with astronomical observations. In this paper, we continue the investigation of the nonlocal de Sitter model of gravity, focusing on finding an appropriate solution for the Schwarzschild-de Sitter metric. We succeeded to solve the equations of motion in a certain approximation. The obtained approximate solution is of particular interest for examining the possible role of non-local de Sitter gravity in describing the effects in galactic dynamics that are usually attributed to dark matter.Comment: 10 page

Digital twin control of multi-axis wood CNC machining center based on LinuxCNC

Abstrack: This paper presents an application of an open architecture control system implemented on a multi-axis wood computer numerical control milling machining center, as a digital twin control. The development of the digital twin control system was motivated by research and educational requirements, especially in the field of configuring a new control system by “virtual commissioning”, enabling the validation of the developed controls, program verification, and analysis of the machining process and monitoring. The considered wood computer numerical control (CNC) machining system is supported by an equivalent virtual machine in a computer-aided design and computer-aided manufacturing (CAD/CAM) environment, as well as in the control system, as a digital twin. The configured virtual machines are used for the verification of the machining program and programming system via machining simulation, which is extremely important in multi-axis machining. Several test wood workpieces were machined to validate the effectiveness of the developed control system based on LinuxCNC

The mechanism of caesium intercalation of graphene

Properties of many layered materials, including copper- and iron-based superconductors, topological insulators, graphite and epitaxial graphene can be manipulated by inclusion of different atomic and molecular species between the layers via a process known as intercalation. For example, intercalation in graphite can lead to superconductivity and is crucial in the working cycle of modern batteries and supercapacitors. Intercalation involves complex diffusion processes along and across the layers, but the microscopic mechanisms and dynamics of these processes are not well understood. Here we report on a novel mechanism for intercalation and entrapment of alkali-atoms under epitaxial graphene. We find that the intercalation is adjusted by the van der Waals interaction, with the dynamics governed by defects anchored to graphene wrinkles. Our findings are relevant for the future design and application of graphene-based nano-structures. Similar mechanisms can also play a role for intercalation of layered materials.Comment: 8 pages, 7 figures in published form, supplementary information availabl

Correction to “Temperature-Dependent High-Speed Dynamics of Terahertz Quantum Cascade Lasers”

Corrections to author affiliation information is presented in the above named paper

Periodontitis as a risk factor for systemic disease: Are microparticles the missing link?

Periodontitis is an oral inflammatory disease affecting the teeth supportive tissue. Its bacterial infectious etiology is well established. Periodontitis has been associated with increased prevalence of systemic diseases such as cardiovascular diseases, diabetes, rheumatoid arthritis, preeclampsia, preterm birth and inflammatory bowel disease. The rational of considering periodontitis as risk factor for systemic disease is the passage of inflammatory cytokines and/or bacteria in the bloodstream, thus affecting distant organs. Membrane microparticles are released by multiple cells in inflammatory environment. Recent data suggested the role of these microparticles in the pathogenic process of many systemic diseases, that can be also associated to periodontitis. We hypothesized that periodontitis could be a chronic reservoir of microparticles, hence elucidating partially the interaction with systemic diseases initiation or progression

Effects of Preterm Birth on Cortical Thickness Measured in Adolescence

Despite the extensive research into brain development after preterm birth, few studies have investigated its long-term effects on cortical thickness. The Stockholm Neonatal Project included infants between 1988 and 1993 with birth weight (BW) ≤1500 g. Using a previously published method, cortical thickness was estimated on T1-weighted 3D anatomical images acquired from 74 ex-preterm and 69 term-born adolescents (mean age 14.92 years). The cortex was significantly thinner in ex-preterm individuals in focal regions of the temporal and parietal cortices as indicated by voxel-wise t-tests. In addition, large regions around the central sulcus and temporal lobe as well as parts of the frontal and occipital lobes tended also to be thinner in the ex-preterm group. Although these results were not significant on voxel-wise tests, the spatially coherent arrangement of the thinning in ex-preterm individuals made it notable. When the group of ex-preterm individuals was divided by gestational age or BW, the thinning tended to be more pronounced in the anterior and posterior poles in those born nearer term or with a BW closer to 1500 g. These results support the notion that preterm birth is a risk factor for long-term development of cortical thickness

Influence of layer thickness to the emission spectra in microcavity organic light emitting diodes

Microcavity organic light emitting diodes (OLEDs) have attracted great attention because they can reduce the width of emission spectra from organic materials, enhance brightness and achieve multipeak emission from the same material. In this work, we have fabricated microcavity OLEDs with widely used organic materials, such as N,N'-di(naphthalene-1-yl)-N,N'-diphenylbenzidine (NPB) as a hole transport layer and tris (8-hydroxyquinoline) (Alq) as emitting and electron transporting layer. These organic materials are sandwiched either between two thick silver mirrors or one thin copper and one thick silver mirrors. The influence of total cavity length (from 164 nm to 243nm) and the cavity Q-factor to the emission behavior has been investigated. In all cases, an OLED without bottom mirror, i.e. with the organic materials sandwiched between indium tin oxide and a thick silver mirror, has been fabricated for comparison. We have characterized the devices with photoluminescence, electroluminescence, and reflectance measurements. Multiple peaks have been observed for some devices at larger viewing angles