Non-liftable Calabi-Yau spaces

We construct many new non-liftable three-dimensional Calabi-Yau spaces in positive characteristic. The technique relies on lifting a nodal model to a smooth rigid Calabi-Yau space over some number field as introduced by the first author and D. van Straten.Comment: 16 pages, 5 tables; v2: minor corrections and addition

The environmental footprint of Holocene societies: a multi-temporal study of trails in the Judean Desert, Israel

The global distribution of footpaths and their inferred antiquity implies that they are widespread spatial and temporal anthropogenic landscape units. Arid environments are of special interest for investigating historically used footpaths, as older routes may preserve better due to minimal modern impact and slower pedogenic processes. Here we examine footpaths in the Judean Desert of the southern Levant, a human hotspot throughout the Holocene. We studied one modern and two archaeological footpaths (one attributed to the Early Bronze Age and one to the Roman period) using micromorphology, bulk samples laboratory analysis, and remote sensing. Field observations and color analysis indicate that footpaths in the studied arid limestone environment can result in brighter surface color than their non-path surroundings. Similar color changes are reflected using both laboratory analysis and high-resolution remote sensing, where the difference is also significant. Microscopically, the footpaths studied tend to be less porous and with fewer biogenic activities when compared to their non-path controls. However, the two ancient footpaths studied do exhibit minimal indicators of biogenic activities that are not detectable in the modern footpath sample. Our study shows that high-resolution remote sensing coupled with micromorphology, while using appropriate local modern analogies, can help to locate and assess both the environmental effect and the antiquity of footpaths

Pathophysiological Factors in the Relationship between Chronological Age and Calculated Lung Age as Detected in a Screening Setting in Community-Dwelling Subjects

Aim: To explore the relationship between pathophysiological factors and premature lung ageing in a cohort of community-dwelling subjects in a health-screening setting. Methods: 16,107 pharmacy customers in Germany (5954 males, 10153 females; mean age 59.7 years)) participated in a lung function screening project by providing demographic data including smoking status and known airway conditions and performing spirometry with a Vitalograph, a spirometry screening device. Lung age was calculated from the spirometric findings, and the difference between chronological age and calculated lung age was analyzed in its relationship to the demographic data in general linear models. Results: In the overall cohort, calculated lung age exceeded chronological age by 10.0 years. Based on the subset of non-smokers not reporting any airway conditions, Vitalograph data in this setting may underestimate FEV1 to some degree but this apparently had little impact on the detection of association of lung age with pathophysiological factors or the corresponding effect sizes. The most important factors associated with greater lung age based on strength of association were presence of dyspnea, being a smoker and reporting a history of COPD or asthma. Corresponding effect sizes for the difference between age and lung age were 6.5, 5.7, 13.9 and 8.3 years over the chronological age. Discussion and Conclusions: These data confirm the usefulness of screening devices of lung function testing for epidemiological but potentially also for pharmaco-epidemiological studies

Footpaths: pedogenic and geomorphological long-term effects of human trampling

Footpaths are of the oldest and most widely distributed forms of human imprint on the landscape. These elongated features are the result of continuous usage of a certain route for walking, at time scales ranging from days to centuries or millennia. In this qualitative investigation, we take a holistic approach combining micromorphology (including voids analysis), chemical soil parameters (such as selective iron oxide dissolution), and remote sensing (spatial distribution and orientation of footpaths in the landscape) to evaluate the long-term residues and environmental effects resulting from the formation of footpaths. Our diverse case studies incorporate footpaths used for recreational and transport purposes in temperate and sub-humid climates from both recent and historical perspectives. A reduction of the large pores was observed down to 3 cm below current and historical surfaces compared to control areas without footpaths. The lower porosity subsequently hinders of the supply of oxygen and/or water into the sub-surface and encourages water stagnation on the compacted footpath surface. These processes result in higher amounts of pedogenic Fe oxides and, at times, macro-organic residues under footpaths and hindering of soil formation. As an additional result of compaction, surface runoff is promoted. The latter may either trigger the initiation of gullies directly downslope from footpaths or lead to incision of the footpaths themselves. Incised footpaths are more likely to occur when the footpath is oriented parallel to the stream network. Once an incised footpath is formed, it may reduce gully erosion susceptibility downslope as the incised footpath acts as a channel that decreases a footpath’s ‘overbank’ flow. With a better understanding of footpaths as landscape units we can (1) pose archaeological questions related to human environmental interaction, (2) assess carbon storage potential under footpaths and (3) use incised footpaths as possible measures against gully erosion

Геофизические исследования скважин для выявления коллекторов и определения их фильтрационно-емкостных свойств на Вынгаяхинском газо-нефтяном месторождении (Тюменская область)

Объектом исследования является месторождение Вынгаяхинское. Цель работы – проектирование комплекса геофизических методов исследования скважин с целью изучения пластов- коллекторов Вынгаяхинского месторождения (ЯНАО). В процессе исследования проводились сбор и анализ геофизических материалов для обоснования оптимального комплекса. В результате исследования предложен комплекс ГИС для выявления и исследования нефтенасыщенных коллекторов. Область применения: предназначаемый комплекс ГИС может применяться на любых месторождениях нефти с терригенно-поровым типом коллекторов. Экономическая значимость работы определяется необходимостью исследований для подсчетов запасов.The object of this study is to deposit Vyngayakhinskoye. The purpose of the work - design of geophysical methods for wells to examine plastov- collectors Vyngayakhinskoye deposit (Yamalo-Nenets District). The study carried out collection and analysis of geophysical data to support the optimum combination. The study proposed a set of GIS for the detection and investigation of oil-saturated reservoir. Scope: intended complex GIS can be used on any oil fields with terrigenous pore type reservoirs. The economic significance of the work is determined by the necessity of research for calculation of reserves

Plasmons in layered structures including graphene

We investigate the optical properties of layered structures with graphene at the interface for arbitrary linear polarization at finite temperature including full retardation by working in the Weyl gauge. As a special case, we obtain the full response and the related dielectric function of a layered structure with two interfaces. We apply our results to discuss the longitudinal plasmon spectrum of several single and double layer devices such as systems with finite and zero electronic densities. We further show that a nonhomogeneous dielectric background can shift the relative weight of the in-phase and out-of-phase mode and discuss how the plasmonic mode of the upper layer can be tuned into an acoustic mode with specific sound velocity.Comment: 18 pages, 6 figure

20th Annual UD International Tea Scheduled

News release announces the 20th Annual International Tea at the University of Dayton with the theme Where In The World Are You

Biomimetic Carbon-Fiber Systems Engineering: A Modular Design Strategy to Generate Biofunctional Composites from Graphene and Carbon Nanofibers

electrical conductivity. It is additionally advantageous if such materials resembled the structural and biochemical features of the natural extracellular environment. Here we show a novel modular design strategy to engineer biomimetic carbon-fiber based scaffolds. Highly porous ceramic zinc oxide (ZnO) microstructures serve as 3D sacrificial templates and are infiltrated with carbon nanotube (CNT) or graphene dispersions. Once the CNTs and graphene uniformly coat the ZnO template, the ZnO is either removed by hydrolysis or converted into carbon by chemical vapor deposition (CVD). The resulting 3D carbon scaffolds are both hierarchically ordered and free-standing. The properties of the micro-fibrous scaffolds were tailored with a high porosity (up to 93 %), high Young’s modulus (~0.027 to ~22 MPa), and an electrical conductivity of (~0.1 to ~330 S/m), as well as different surface compositions. Cell viability and fibroblast proliferation rate and protein adsorption rate assays have shown that the generated scaffolds are biocompatible and have a high protein adsorption capacity (up to 77.32 ±6.95 mg/cm3), so that they not only are able to resemble the ECM structurally, but also biochemically. The scaffolds also allow for the successful growth and adhesion of fibroblast cells showing that we provide a novel, highly scalable modular design strategy to generate biocompatible carbon-fiber systems that mimic the extracellular matrix with the additional feature of conductivity.RA gratefully acknowledges partial project funding by the Deutsche Forschungsgemeinschaft under contract FOR1616. This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No. GrapheneCore2 785219. CS is supported by the European Research Council (ERC StG 336104 CELLINSPIRED, ERC PoC 768740 CHANNELMAT), by the German Research Foundation (RTG 2154, SFB 1261 project B7). MT acknowledges support from the German Academic Exchange Service (DAAD) through a research grant for doctoral candidates (91526555-57048249). We acknowledge funding from EPSRC grants EP/P02534X/1, ERC grant 319277 (Hetero2D) the Royal Academy of Engineering Enterprise Scheme, the Trinity College, Cambridge, and the Isaac Newton Trust