Deforming Lie algebras to Frobenius integrable non-autonomous Hamiltonian systems

Motivated by the theory of Painlev\'e equations and associated hierarchies, we study non-autonomous Hamiltonian systems that are Frobenius integrable. We establish sufficient conditions under which a given finite-dimensional Lie algebra of Hamiltonian vector fields can be deformed to a time-dependent Lie algebra of Frobenius integrable vector fields spanning the same distribution as the original algebra. The results are applied to quasi-St\"ackel systems.Comment: 14 pages, no figures. We repaired Example 5 and also made some minor amendments in the tex

Uncertainty based multi-step seismic analysis for near-surface imaging

Near-surface seismic surveys are often designed for surface wave and seismic tomographic analysis. In recent years, seismic imaging methods have been more frequently used at this scale. Recognition of near-surface structures using a single method is insufficient because of the ambiguity of the inversion problem. As a solution, the authors propose a multi-step approach, where several different seismic methods are used in a particular order, to achieve an optimal model. A multi-method approach allows utilisation of awhole spectrum of recorded data, even the elements that are treated as background noise in other techniques. In classical processing approach, information about data uncertainty is often omitted or used in the simplest way for the single method only. This work presents an updated approach to uncertainty analysis by transferring estimated uncertainty between processing steps. By assuming that every consecutively applied method is more certain, the authors were able to obtain accurate velocity fields for seismic imaging, as the main information received from the previous steps. Based on information from multiple methods, a seismic stack in the depth domain was created as a final result, with an estimate of uncertainty

Wooden sacral architecture in Greater Poland. An interdisciplinary case study of the church in Domachowo

Sacred wooden architecture in Poland is a huge and still unrecognised research problem. It covers a number of issues of interdisciplinary character: from the properties of building materials and carpentry techniques, through constructionand architectural-spatial solutions, to cultural and natural conditions. Hence, the best way to study this problem is interdisciplinary research. The necessity of cooperation of representatives of various scientific disciplines became the basis for creating a team to study the wooden church of St Michael the Archangel in Domachowo, so far dated to 1568. As researchers representing various disciplines (including archaeology, history, art history, history of architecture, architecture, architectural conservation), we cite sources and research that allow us to formulate a thesis that the past of the Domachowo church dates back to the 14th century. Moreover, we present the research and methodological problems inscribed in the aforementioned church building, understood as a whole. Such a multifaceted approach allows us to redefine the current knowledge about the church in Domachowo.Sacred wooden architecture in Poland is a huge and still unrecognised research problem. It covers a number of issues of interdisciplinary character: from the properties of building materials and carpentry techniques, through constructionand architectural-spatial solutions, to cultural and natural conditions. Hence, the best way to study this problem is interdisciplinary research. The necessity of cooperation of representatives of various scientific disciplines became the basis for creating a team to study the wooden church of St Michael the Archangel in Domachowo, so far dated to 1568. As researchers representing various disciplines (including archaeology, history, art history, history of architecture, architecture, architectural conservation), we cite sources and research that allow us to formulate a thesis that the past of the Domachowo church dates back to the 14th century. Moreover, we present the research and methodological problems inscribed in the aforementioned church building, understood as a whole. Such a multifaceted approach allows us to redefine the current knowledge about the church in Domachowo

Occurrence and extraction of implantable cardioverter-defibrillator leads with conductor externalization

   Background: The increasing number of patients with implantable cardioverter-defibrillators (ICD) contributes to the rising number of patients qualifying for a transvenous lead extraction (TLE) due to infection, vascular or lead failure related indications. The purpose of this study was to perform a retrospective analysis of the occurrence of conductor externalization in TLE patients and to assess the success rate in the extraction of these leads. Methods: TLE procedure was performed between 2012 and 2014 of 428 electrodes in 259 patients. Out of these, 143 (33.4%) leads in 138 (52.9%) patients were ICD leads. The indications for the TLE in ICD patients were: infection in 37 patients, lead failure in 84 patients, and others in 17 patients. Conductor externalization was observed in 8 ICD leads (5.6%) in 8 (5.8%) patients. The mean dwell­ing time for externalized leads was 87.9 (55 to 132) months compared to 60.1 (3 to 246) months of the remaining 135 ICD leads (p = 0.0329). All externalized leads were successfully and completely extracted using device traction, mechanical telescopic sheaths and/or autorotational cutting sheaths. No complica­tions of lead extraction procedures were observed in 8 patients with externalization. Results: Patients with lead externalization were often in a better New York Heart Association func­tional class (I or II) compared to those in the rest of the study group (p = 0.0212). Conclusions: Conductor externalization is a rare finding in patients undergoing TLE. This occurs with different manufacturers and lead types. In this complication transvenous lead extraction with the mechanical extraction tools can be safely performed.

Geophysical imaging of permafrost in the SW Svalbard – the result of two high arctic expeditions to Spitsbergen

"The Arctic regions are the place of the fastest observed climate change. One of the indicators of such evolution are changes occurring in the glaciers and the subsurface in the permafrost. The active layer of the permafrost as the shallowest one is well measured by multiple geophysical techniques and in-situ measurements." (fragm.

Highly sensitive luminescence nanothermometry and thermal imaging facilitated by phase transition

Currently available temperature measurements or imaging at nano-micro scale are limited to fluorescent molecules and luminescent nanocrystals, whose spectral properties respond to temperature variation. The principle of operation of these conventional temperature probes is typically related to temperature induced multiphonon quenching or temperature dependent energy transfers, therefore, above 12%/K sensitivity and high thermal resolution remain a serious challenge. Here we demonstrate a novel class of highly sensitive thermographic phosphors operating in room temperature range with sub-kelvin thermal resolution, whose temperature readings are reproducible, luminescence is photostable and brightness is not compromised by thermal quenching. Corroborated with phase transition structural characterization and high spatio-temporal temperature imaging, we demonstrated that optically active europium ions are highly and smoothly susceptible to monoclinic to tetragonal phase transition in nanocrystalline (54 ± 14 nm) LiYO2 host, which is evidenced by changed number and the splitting of Stark components as well as by smooth variation of contribution between magnetic and electric dipole transitions. Further, reducing the size of phosphor from bulk to nanocrystalline matrix, shifted the phase transition temperature from 100 °C down to room temperature. These findings provide insights into the mechanism underlaying phase transition based luminescence nanothermometry and motivate future research toward new, highly sensitive, high temporal and spatial resolution nano-thermometers aiming at precise studying heat generation or diffusion in numerous biological and technology applications

Recognition of the varying permafrost conditions in the SW Svalbard by multiple geophysical methods [abstract]

"In recent years, rapid climatic changes and their impact are widely visible and recognizable around the world. The Atlantic sector of the Arctic is the place of the strongest observed changes. As a result, such changes are already destabilizing the arctic systems including the glaciers and the permafrost that strongly affects the Arctic’s physical and biological systems."[...] (fragm.

Impact of Stripe Shape on the Reflectivity of Monolithic High Contrast Gratings

Monolithic high contrast gratings (MHCGs) composed of a one-dimensional grating patterned in a monolithic layer provide up to 100% optical power reflectance and can be fabricated in almost any semiconductor and dielectric material used in modern optoelectronics. MHCGs enable monolithic integration, polarization selectivity, and versatile phase tuning. They can be from 10 to 20 times thinner than distributed Bragg reflectors. The subwavelength dimensions of MHCGs significantly reduce the possibility of ensuring the smoothness of the sidewalls of the MHCG stripes and make precise control of the shape of the MHCG stripe cross-section difficult during the etching process. The question is then whether it is more beneficial to improve the etching methods to obtain a perfect cross-section shape, as assumed by the design, or whether it is possible to find geometrical parameters that enable high optical power reflectance using the shape that a given etching method provides. Here, we present a numerical study supported by the experimental characterization of MHCGs fabricated in various materials using a variety of common surface nanometer-scale shaping methods. We demonstrate that MHCG stripes with an arbitrary cross-section shape can provide optical power reflectance of nearly 100%, which greatly relaxes their fabrication requirements. Moreover, we show that optical power reflectance exceeding 99% with a record spectral bandwidth of more than 20% can be achieved for quasi-Trapezoidal cross-sections of MHCGs. We also show that sidewall corrugations of the MHCG stripes have only a slight impact on MHCG optical power reflectance if the amplitude of the corrugation is less than 16% of the MHCG period. This level of stripe fabrication precision can be achieved using the most current surface etching methods. Our results are significant for the design and production of a variety of photonic devices employing MHCGs. The flexibility with regard to cross-section shape facilitates the reliable fabrication of highly reflective subwavelength grating mirrors. This in turn will enable the manufacture of monolithically integrated high-quality-factor optical micro-and nanocavity devices

Cabbage and fermented vegetables : From death rate heterogeneity in countries to candidates for mitigation strategies of severe COVID-19

Large differences in COVID-19 death rates exist between countries and between regions of the same country. Some very low death rate countries such as Eastern Asia, Central Europe, or the Balkans have a common feature of eating large quantities of fermented foods. Although biases exist when examining ecological studies, fermented vegetables or cabbage have been associated with low death rates in European countries. SARS-CoV-2 binds to its receptor, the angiotensin-converting enzyme 2 (ACE2). As a result of SARS-CoV-2 binding, ACE2 downregulation enhances the angiotensin II receptor type 1 (AT(1)R) axis associated with oxidative stress. This leads to insulin resistance as well as lung and endothelial damage, two severe outcomes of COVID-19. The nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is the most potent antioxidant in humans and can block in particular the AT(1)R axis. Cabbage contains precursors of sulforaphane, the most active natural activator of Nrf2. Fermented vegetables contain many lactobacilli, which are also potent Nrf2 activators. Three examples are: kimchi in Korea, westernized foods, and the slum paradox. It is proposed that fermented cabbage is a proof-of-concept of dietary manipulations that may enhance Nrf2-associated antioxidant effects, helpful in mitigating COVID-19 severity.Peer reviewe