Low-temperature reactions: Tunnelling in space.

International audienceChemical reactions with activation barriers generally slow to a halt in the extreme cold of dense interstellar clouds. Low-temperature experiments on the reaction of OH with methanol have now shown that below 200 K there is a major acceleration in the rate that can only be explained by enhanced quantum mechanical tunnelling through the barrier

Risk, Clinical Course, and Outcome of Ischemic Stroke in Patients Hospitalized With COVID-19: A Multicenter Cohort Study

BACKGROUND AND PURPOSE: The frequency of ischemic stroke in patients with coronavirus disease 2019 (COVID-19) varies in the current literature, and risk factors are unknown. We assessed the incidence, risk factors, and outcomes of acute ischemic stroke in hospitalized patients with COVID-19. METHODS: We included patients with a laboratory-confirmed SARS-CoV-2 (severe acute respiratory syndrome coronavirus-2) infection admitted in 16 Dutch hospitals participating in the international CAPACITY-COVID registry between March 1 and August 1, 2020. Patients were screened for the occurrence of acute ischemic stroke. We calculated the cumulative incidence of ischemic stroke and compared risk factors, cardiovascular complications, and in-hospital mortality in patients with and without ischemic stroke. RESULTS: We included 2147 patients with COVID-19, of whom 586 (27.3%) needed treatment at an intensive care unit. Thirty-eight patients (1.8%) had an ischemic stroke. Patients with stroke were older but did not differ in sex or cardiovascular risk factors. Median time between the onset of COVID-19 symptoms and diagnosis of stroke was 2 weeks. The incidence of ischemic stroke was higher among patients who were treated at an intensive care unit (16/586; 2.7% versus nonintensive care unit, 22/1561; 1.4%; P=0.039). Pulmonary embolism was more common in patients with (8/38; 21.1%) than in those without stroke (160/2109; 7.6%; adjusted risk ratio, 2.08 [95% CI, 1.52–2.84]). Twenty-seven patients with ischemic stroke (71.1%) died during admission or were functionally dependent at discharge. Patients with ischemic stroke were at a higher risk of in-hospital mortality (adjusted risk ratio, 1.56 [95% CI, 1.13–2.15]) than patients without stroke. CONCLUSIONS: In this multicenter cohort study, the cumulative incidence of acute ischemic stroke in hospitalized patients with COVID-19 was ≈2%, with a higher risk in patients treated at an intensive care unit. The majority of stroke patients had a poor outcome. The association between ischemic stroke and pulmonary embolism warrants further investigation

Nonlinear temporal dynamics of cerebral small vessel disease: The RUN DMC study

Objective: To investigate the temporal dynamics of cerebral small vessel disease (SVD) by 3 consecutive assessments over a period of 9 years, distinguishing progression from regression. Methods: Changes in SVD markers of 276 participants of the Radboud University Nijmegen Diffusion Tensor and Magnetic Resonance Imaging Cohort (RUN DMC) cohort were assessed at 3 time points over 9 years. We assessed white matter hyperintensities (WMH) volume by semiautomatic segmentation and rated lacunes and microbleeds manually. We categorized baseline WMH severity as mild, moderate, or severe according to the modified Fazekas scale. We performed mixed-effects regression analysis including a quadratic term for increasing age. Results: Mean WMH progression over 9 years was 4.7 mL (0.54 mL/y; interquartile range 0.95–5.5 mL), 20.3% of patients had incident lacunes (2.3%/y), and 18.9% had incident microbleeds (2.2%/y). WMH volume declined in 9.4% of the participants during the first follow-up interval, but only for 1 participant (0.4%) throughout the whole follow-up. Lacunes disappeared in 3.6% and microbleeds in 5.7% of the participants. WMH progression accelerated over time: including a quadratic term for increasing age during follow-up significantly improved the model (p < 0.001). SVD progression was predominantly seen in participants with moderate to severe WMH at baseline compared to those with mild WMH (odds ratio [OR] 35.5, 95% confidence interval [CI] 15.8–80.0, p < 0.001 for WMH progression; OR 5.7, 95% CI 2.8–11.2, p < 0.001 for incident lacunes; and OR 2.9, 95% CI 1.4–5.9, p = 0.003 for incident microbleeds). Conclusions: SVD progression is nonlinear, accelerating over time, and a highly dynamic process, with progression interrupted by reduction in some, in a population that on average shows progression.A. Tuladhar is a junior staff member of the Dutch Heart Foundation (grant 2016T044). E. van Dijk received a personal fellowship from the Dutch Brain Foundation (H04-12; F2009[1]-16). L. Rutten-Jacobs is supported by a British Heart Foundation Immediate Research Fellowship (FS/15/61/31626). C. Klijn is supported by a clinical established investigator grant of the Dutch Heart Foundation (grant 2012 T077) and an Aspasia grant from The Netherlands Organisation for Health Research and Development (ZonMw grant 015.008.048). F. de Leeuw is supported by a clinical established investigator grant of the Dutch Heart Foundation (grant 2014 T060), by a VIDI innovational grant from The Netherlands Organisation for Health Research and Development (ZonMw grant 016.126.351), and the MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente

Одноколейные тракторно-ледяные дороги: учебное пособие для лесотехнических вузов

Книга содержит описание конструкций однополозных тракторных саней, расчет основных деталей саней, краткие технические условия проектирования одноколейных тракторно-ледяных дорог, правила постройки и эксплуатации ледяных дорог и основы организации тракторного хозяйства на базе одноколейных ледяных дорог. Книга предназначена в качестве учебного пособия для лесотехнических вузов, но может также служить практическим пособием и для высшего технического персонала лесозаготовительных предприятий Наркомлеса СССР.0|7|Предисловие [c. 7]0|8|Введение [c. 8]0|11|Возникновение и развитие конструкции однополозных саней [c. 11]1|11|Первые опыты [c. 11]1|12|Принцип работы одноколейной ледяной дороги и теоретические основания проектирования однополозных саней [c. 12]1|17|Конструкция первых однополозных саней [c. 17]1|17|Однополозные сани Востокостальлеса [c. 17]1|19|Одкополозные сани ЦНИИМЭ, модель Б [c. 19]1|21|Однополозные сани на базе поковок тракторных двухполозных саней модели Д [c. 21]1|22|Однополозные сани Я. И. Гинзбурга модели 1939 г. [c. 22]1|33|Однополозные сани ГЗЯ-2 [c. 33]1|39|Варианты соединения коника с полозом [c. 39]1|39|Модернизированные однополозные сани на базе поковок саней модели Свердлеса и Востокостальлеса [c. 39]1|44|Бескониковые однополозные сани конструкции СибНИИЛХЭ [c. 44]1|46|Буферно-прицепные устройства трактора конструкции УЛТИ, Сотринского мехлесопункта и Стройлеспроекта [c. 46]1|48|Автоматическая сцепка тракторных саней [c. 48]1|49|Рама для перевозки коротья на однополозных санях [c. 49]1|51|Расчет саней [c. 51]1|51|Расчет полоза [c. 51]1|58|О форме подрезов [c. 58]0|61|Постройка одноколейных ледяных дорог [c. 61]1|61|Условия применения, сырьевая база и порядок оформления строительства [c. 61]1|62|Технические условия проектирования одноколейных ледяных дорог [c. 62]1|72|Изыскания трасс одноколейных ледяных дорог [c. 72]1|73|Строительные работы на одноколейных ледяных дорогах [c. 73]1|85|Дорожные орудия для строительства одноколейных ледяных дорог [c. 85]1|91|Цистерны для поливки ледяной дороги [c. 91]1|91|Насосные станции [c. 91]0|95|Эксплуатация ледяных дорог [c. 95]1|95|Техническая характеристика тяговых машин [c. 95]1|107|Эксплуатация газогенераторных тракторов на лесовывозке по ледяным дорогам [c. 107]1|115|Правила вождения поездов [c. 115]1|117|Формирование состава и маневры [c. 117]1|117|Содержание и ремонт пути ледяной дороги [c. 117]1|119|Техника безопасности при вывозке леса по тракторным ледяным дорогам [c. 119]1|121|Основные правила по технике безопасности для тракторного лесотранспорта [c. 121]0|123|Приложения [c. 123]1|123|Детали однополозных саней ГЗЯ-1 [c. 123]1|136|Детали модернизированных однополозных саней на базе поковок саней Свердллеса [c. 136]1|141|Краткая техническая характеристика гусеничных тракторов Челябинского тракторного завода [c. 141]0|143|Оглавление [c. 143

Characterization of supplementary cementitious materials by thermal analysis

Working Group 1 of RILEM TC 238-SCM ‘Hydration and microstructure of concrete with supplementary cementitious materials (SCMs)’ is defining best practices for the physical and chemical characterization of SCMs, and this paper focusses on their thermal analysis. Thermogravimetric analysis (TGA) can provide valuable data on the chemical and mineralogical composition of SCMs. Loss-on-ignition (LOI) testing is a commonly used, standardized, but less sophisticated version of TGA that measures mass at endpoints only, with heating generally in air. In this paper we describe the use of TGA and LOI to characterize Portland cement with limestone additions, coal combustion fly ashes, ground-granulated blast furnace slag, calcined clays, and natural pozzolans. This paper outlines the value and limitations of TGA and LOI (in the formats defined in different standards regimes) for material characterization, and describes testing methods and analysis. TGA testing parameters affect the mass loss recorded at temperatures relevant for LOI measurements (700–1000 °C) of slags and fly ashes, mainly associated with oxidation reactions taking place upon heating. TGA of clays and natural pozzolans is utilized to identify optimal calcination conditions leading to dehydroxylation and consequent structural amorphization, particularly for kaolinite. However, dehydroxylation and amorphization do not occur at similar temperatures for all clays, limiting the applicability of TGA for this purpose. Although TGA is widely utilized for characterization of SCMs, the testing parameters significantly affect the results obtained, and TGA results require careful interpretation. Therefore, standardization of TGA testing conditions, particularly for LOI determination of slags and fly ashes, is required

Effectiveness of waste minimisation projects in reducing water demand by UK industry

There is growing interest in managing water demand in the UK. A series of waste minimization clubs have been set up within the country and this paper identifies the effectiveness of these clubs in reducing the demand for water within industry. Membership of these clubs is voluntary and the only incentive for industry to reduce water consumption, and consequently the production of effluent, is the almost immediate financial saving made by the company, often achieved by accounting for the water consumption and loss within site from the point of input from the water supplier to output in the form of effluent. On average, companies are able to reduce water consumption by up to 30 percent. If the entire industrial sector within the UK were to achieve this degree of savings, it is possible that approximately 1300Ml/d could be saved

Fostering coastal resilience to climate change vulnerability in Bangladesh, Brazil, Cameroon and Uruguay: a cross-country comparison

© 2017, Springer Science+Business Media B.V. This paper describes a comparative study of four different cases on vulnerability, hazards and adaptive capacity to climate threats in coastal areas and communities in four developing countries: Bangladesh, Brazil, Cameroon and Uruguay. Coastal areas are vulnerable to sea-level rise (SLR), storm surges and flooding due to their (i) exposure, (ii) concentration of settlements, many of which occupied by less advantaged groups and (iii) the concentration of assets and services seen in these areas. The objective of the paper is twofold: (i) to evaluate current evidence of coastal vulnerability and adaptive capacity and (ii) to compare adaptation strategies being implemented in a sample of developing countries, focusing on successful ones. The followed approach for the case evaluation is based on (i) documenting observed threats and damages, (ii) using indicators of physical and socioeconomic vulnerability and adaptive capacity status and (iii) selecting examples of successful responses. Major conclusions based on cross-case comparison are (a) the studied countries show different vulnerability, adaptive capacity and implementation of responses, (b) innovative community-based (CBA) and ecosystem-based adaptation (EbA) and (c) early warning systems are key approaches and tools to foster climate resilience. A recommendation to foster the resilience of coastal communities and services is that efforts in innovative adaptation strategies to sea-level rise should be intensified and integrated with climate risk management within the national adaption plans (NAPAs) in order to reduce the impacts of hazards

IWM Duxford

Visit Imperial War Museum Duxford for a huge day out. See historic aircraft take to the skies from the airfield where Spitfires first flew. Get up close to gigantic aircraft at Europe’s largest air museum and uncover hundreds of personal stories