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The Hα sky in three dimensions
No full textWe combine parallax distances to nearby O stars with parsec-scale resolution three-dimensional dust maps of the local region of the Milky Way (within 1.25 kpc of the Sun) to simulate the transfer of Lyman continuum photons through the interstellar medium (ISM). Assuming a fixed gas-to-dust ratio, we determine the density of ionized gas, electron temperature, and Hα emissivity throughout the local Milky Way. There is good morphological agreement between the predicted and observed Hα all-sky map of the Wisconsin Hα Mapper. We find that our simulation underproduces the observed Hα emission while overestimating the sizes of H II regions, and we discuss ways in which agreement between simulations and observations may be improved. Of the total ionizing luminosity of 5.84 × 1050 photons s−1, 15 per cent is absorbed by dust, 64 per cent ionizes ‘classical’ H II regions, 11 per cent ionizes the diffuse warm ionized medium, and 10 per cent escapes the simulation volume. We find that 18 per cent of the high-altitude (|b| > 30◦) Hα arises from dust scattered rather than direct emission. These initial results provide an impressive validation of the three-dimensional dust maps and O-star parallaxes, opening a new frontier for studying the ionized ISM’s structure and energetics in three dimensions
Evaluating serpentinization as a source of phosphite to microbial communities in hydrothermal vents
No full textPrevious studies have documented the presence of phosphite, a reduced and highly soluble form of phosphorus, in serpentinites, which has led to the hypothesis that serpentinizing hydrothermal vents could have been an important source of bioavailable phosphorus for early microbial communities in the Archean. Here, we test this hypothesis by evaluating the genomic hallmarks of phosphorus usage in microbial communities living in modern hydrothermal vents with and without influence from serpentinization. These genomic analyses are combined with results from a geochemical model that calculates phosphorus speciation during serpentinization as a function of temperature, water:rock ratio, and lithology at thermodynamic equilibrium. We find little to no genomic evidence of phosphite use in serpentinizing environments at the Voltri Massif or the Von Damm hydrothermal field at the Mid Cayman Rise, but relatively more in the Lost City hydrothermal field, Coast Range Ophiolite Microbial Observatory, The Cedars and chimney samples from Old City hydrothermal field and Prony Bay hydrothermal field, as well as in the non-serpentinizing hydrothermal vents at Axial Seamount. Geochemical modeling shows that phosphite production is favored at ca 275-325°C and low water:rock ratios, which may explain previous observations of phosphite in serpentinite rocks; however, most of the initial phosphate is trapped in apatite during serpentinization, suppressing the absolute phosphite yield. As a result, phosphite from serpentinizing vents could have supported microbial growth around olivine minerals in chimney walls and suspended aggregates, but it is unlikely to have fuelled substantial primary productivity in diffusely venting fluids during life’s origin and evolution in the Archean unless substrates equivalent to dunites (composed of >90 wt% olivine) were more common
Cognitive perception of circulating oxygen in seals is the reason they don’t drown
No full textMarine mammals rely on maintaining sufficient blood oxygen levels while diving to prevent drowning. Generally, oxygen is cognitively imperceptible to mammals that instead sense rising carbon dioxide as a proxy for low oxygen. Not perceiving oxygen, however, is risky for diving mammals. We argue that any ability to alter dives based upon direct perception of oxygen should have been strongly selected for. We exposed diving seals to inhaled gas mixes that were experimentally altered to affect circulating levels of oxygen and carbon dioxide. Dive duration was positively correlated with circulating oxygen levels but unaffected by carbon dioxide levels and pH. These results suggest that seals do cognitively perceive circulating oxygen and use this to alter dive behavior. Marine mammals have adapted to an underwater environment and spend long periods of time underwater foraging despite the need for breathing air. As such, they are especially susceptible to low blood oxygen levels, which could lead to drowning while submerged. McKnight et al. exposed diving gray seals to various gas mixes and found that the seals responded to low levels of blood oxygen but not high levels of carbon dioxide (see the Perspective by Hawkes and Kendall-Bar). Nearly all other mammals are insensitive to blood oxygen levels, instead gauging blood oxygen by sensing increasing carbon dioxide. Direct sensing of oxygen levels likely improves diving efficiency. ?Sacha Vignier
Traversing the multiple nested geographies of NUTs based entrepreneurial ecosystems
No full textEntrepreneurial Ecosystems (EEs) have quickly become a key lens for exploring regional entrepreneurial phenomena. Thus far there appears little consensus around the most relevant geographical unit of analysis for examining EEs however, both from a theoretical and an empirical perspective. In this paper, we set out to test whether wider EE geographical units (such as UK regions) have any meaningful relevance to the small firms and their business operations. To address this concern this paper undertakes an empirical analysis of a loan guarantee scheme in the UK, the Recovery Loan Scheme (RLS). Through the empirical lens of the UK SME support scheme, the RLS, we test the relevance of different levels of EE geographical units including NUTS 1, NUTS 2 and NUTS 3. In the case of the UK, which is a diverse collection of nations (England, and three devolved nations, Scotland, Wales, and Northern Ireland), we found that the three devolved nations, and also London shows much larger and stronger higher order spatial effects on their lower order constituent spatial levels. This suggests that outside of London, and the devolved nations, simply analysing NUTS 1 regions does not appear to be the appropriate level if we want to understand the inherent spatial dynamics of small firm ecosystems. Rather, we need to go to smaller spatial levels to establish the true nature of the ecosystem relevant to the small firm. The policy implications point toward the need for properly tailored localised policy
Encounters with New Cultures – a New Web Resource Offering Cultural Encounter Exercises to Develop Intercultural Competence
No full textInteracting with people from different cultural backgrounds is often an enriching and rewarding experience but can also cause confusion and conflict owing to differing behavioural norms and ways of looking at the world. This presentation will introduce a new web resource that curates and shares Cultural Encounter Exercises, which can be used in classes or workplace learning settings to simulate and encourage reflection on intercultural communication scenarios that learners may encounter either at home or abroad. The resource can be embedded into credit-bearing modules or used as part of co-curricular provision. We will demonstrate how the resource can be used to have a positive impact on student experience
Retrospective review on reticular materials:facts and figures over the last 30 years
No full textThe field of reticular materials, such as metal–organic frameworks (MOFs) and covalent organic frameworks (COFs), is expanding continuously – be it in terms of novel structures, advanced characterization techniques, or record-breaking physical properties for applications. This timeline review reflects on the progress over the past 30 years, complemented by input from the community of active researchers. Owing to a global, crowdsourced survey of 228 researchers that is conducted through an online questionnaire, recent insights into the demographics of the field are given. Besides revealing how it works, publish, and interact, the review highlights both academic and industrial milestones. The contemporary trends are described, both at the level of material development and their suitability for a range of applications. To pave the way for newcomers to the field, some remaining challenges and steps to overcome them are discussed. The findings from this contemplative review aim to shape the future course of research in this domain
SHPIRTI RUS APO MENDЁSIA IMPERIALISTE?
No full textTranslated from the English into Albanian by Bardhyl Selimi; introduced by Meehmet Elezi.Autori i shkrimit të mëposhtëm, Tomas (Tomasz) Kamusella, është profesor në unversitetin e St Andrews, Skoci. Akademik me interesa të gjera, autor i shumë studimeve e botimeve. Jemi takuar në Tiranë.Këtu ofron një qasje tjetër, të veçantë, për letërsinë ruse.Mendoj se shkrime të tilla janë në thelb emancipuese. Ato nxitin me u çlirue nga skemat dhe vlerësimet e standardizuara. Ftojnë me gjykue me sy kritik, duke zbuluar të pathëna që mund të shkojnë deri në zhbërje mitesh.Mehmet ELEZ
Thermal expansion of lithiated silicon (Li<sub>13</sub>Si<sub>4</sub> and Li<sub>7</sub>Si<sub>3</sub>) anodes:a powder neutron diffraction study
No full textWhilst at room temperature structural changes on lithiation of the silicon electrode are hard to study due to formation of amorphous phases, at high temperatures, used in thermal batteries, clear phase changes linked to voltage plateaux are observed. Here we report results from a galvanostatic discharge of a FeS2/LiCl–KCl/Li13Si4 cell at 500 °C. The cell discharge showed a flat voltage plateau between Li13Si4 and Li7Si3 which indicates that both phases are in equilibrium and are line phases. In situ powder neutron diffraction study of two lithiated phases of silicon, Li13Si4 and Li7Si3, was performed. The two phases were heated from room temperature to 500 °C. This showed the phases did not become amorphous and did not undergo phase changes, with both phases being remarkably stable. The variation with temperature of the unit cell parameters was linear. The volumetric thermal expansion coefficient of Li13Si4 is 99.3 × 10−6 °C−1 and Li7Si3 is 106 × 10−6 °C−1. The volumetric thermal expansion of the two phases is significantly larger than that of silicon and closer to the thermal expansion of lithium metal. Thus, the LixSi electrode is mechanically closer to lithium than to silicon, and it can be considered as silicon clusters embedded within the lithium array rather than the silicon lattice hosting lithium
Oxford Handbook of Banking, 4th Edition
No full textThe Oxford Handbook of Banking (4th edition) provides an overview and analysis of developments and research in banking written by leading researchers in the field. This handbook will appeal to graduate students of economics, banking and finance, academics, practitioners, regulators, and policy makers. Consequently, the handbook strikes a balance between abstract theory, empirical analysis, and practitioner and policy-related material.This handbook is a one-stop source of relevant research in banking. It examines: the fundamentals of banking; traditional and new challenges to the banking model; models for banking services delivery; regulatory and policy perspectives; and global, regional and country perspectives on banking This fourth edition comprises new chapters and material, including banks and financial markets in a digital age, FinTech and BigTechs, financial literacy, financial inclusion, sustainable banking, stress testing and macroprudential regulation
Igneous rocks as a viable source of fixed nitrogen to the prebiotic world
No full textThe origin and early evolution of life on Earth and other habitable worlds requires constant supply of ammonic nitrogen (N). Previously proposed abiotic ammonium sources rely on sporadic and heterogeneously distributed high energy processes, such as lightning, subaerial volcanic degassing, or deep sea hydrothermal vents to generate bioavailable nitrogen from atmospheric N2 gas. Here we explore weathering of ammonium contained in felsic igneous rocks as an alternative source. We find that this process could have supplied 108–109 mol yr−1 of bioavailable N to surface environments in the early Archean, leading to dissolved concentrations of 0.023 ± 0.017 μM in freshwater and 0.01–0.1 μM in seawater. In terrestrial settings, evaporation paired with elevated N supplies from locally enriched felsic bedrock may have led to concentrations approaching 1 μM. Rock weathering would thus have constituted a smaller flux than the sum of all proposed high energy sources of fixed N, but with the major benefit that it was reliably present, especially in terrestrial settings. Weathering of differentiated igneous rocks should thus be considered in models of the emergence of life on Earth and beyond