103 research outputs found
Влияние теплофизических характеристик материалов на скорость кристаллизации частицы на подложке
Гидроимпульсный силовой механизм сваебойной машины в условиях обустройства месторождений
AbstractObjectivesThis study sought to evaluate whether objective assessment of the myocardial functional reserve, using strain rate imaging (SRI), allows accurate detection of viable myocardium.BackgroundStrain rate imaging is a new echocardiographic modality that allows quantitative assessment of segmental myocardial contractility.MethodsIn 37 patients (age 58 ± 9 years) with ischemic left ventricular dysfunction, myocardial viability was assessed using low-dose (10 μg/kg body weight per min) two-dimensional dobutamine stress echocardiography (DSE), tissue Doppler imaging, SRI and 18F-fluorodeoxyglucose (18FDG) positron emission tomography (PET). The peak systolic tissue Doppler velocity and peak systolic myocardial strain rate were determined at baseline and during low-dose dobutamine stress from the apical views.ResultsA total of 192 segments with dyssynergy at rest were classified by 18FDG PET as viable in 94 and nonviable in 98. An increase of peak systolic strain rate from rest to dobutamine stimulation by more than −0.23 1/s allowed accurate discrimination of viable from nonviable myocardium, as determined by 18FDG PET with a sensitivity of 83% and a specificity of 84%. Receiver operating characteristic (ROC) curve analysis showed an area under the curve for prediction of nonviable myocardium, as determined by 18FDG PET using SRI, of 0.89 (95% confidence interval [CI] 0.88 to 0.90), whereas the area under the ROC curve using tissue Doppler imaging was 0.63 (95% CI 0.61 to 0.65).ConclusionsThe increase in the peak systolic strain rate during low-dose dobutamine stimulation allows accurate discrimination between different myocardial viability states. Strain rate imaging is superior to two-dimensional DSE and tissue Doppler imaging for the assessment of myocardial viability
Evaluation of aortic root for definition of prosthesis size by magnetic resonance imaging and cardiac computed tomography: implications for transcatheter aortic valve implantation
МОДЕЛИРОВАНИЕ ВЛИЯНИЯ СКОРОСТИ ВЗАИМОДЕЙСТВУЮЩИХ ЧАСТИЦ И ПУЗыРЬКОВ НА ВОЗМОЖНОСТЬ ОБРАЗОВАНИЯ ФЛОТАЦИОННОГО КОМПЛЕКСА
Проблема и ее связь с научными и практическими задачами. Уголь пред-ставляет собой ценное сырье для дальнейшей химической переработки с целью получения необходимых для промышленности продуктов, а также является од-ним из главных источников получения тепловой энергии. Современные уг-леобогатительные предприятия постоянно сталкиваются с проблемой обогаще-ния шламов
МИТНЕ ЗАКОНОДАВСТВО УКРАЇНИ ЯК ОСНОВА КАРДИНАЛЬНИХ ЗМІН В СИСТЕМІ УПРАВЛІННЯ ЗЕД
Стаття присвячена аналізу та узагальненню
сучасних змін в митному законодавстві України, встановленню невирішених проблем та
перспективам розвитку системи управління
зовнішньоекономічною діяльністю в Україні на
рівні держави на основі еволюції митно-тарифної політики та вдосконалення законодавства.The article is devoted to the analysis and
generalization of the temporary changes in the customs legislation of Ukraine, and determination of the unsolved problems in this sphere. Much attention is paid to the prospects of the development of Ukrainian foreign economic activity regulation system on the basis of customs-tariff politics
evolution and legislation improvement
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Biases in comparative analyses of extinction risk: mind the gap
. Comparative analyses are used to address the key question of what makes a species more prone to extinction by exploring the links between vulnerability and intrinsic species’ traits and ⁄ or extrin- sic factors. This approach requires comprehensive species data but information is rarely available for all species of interest. As a result comparative analyses often rely on subsets of relatively few species that are assumed to be representative samples of the overall studied group.
2. Our study challenges this assumption and quantifies the taxonomic, spatial, and data type biases associated with the quantity of data available for 5415 mammalian species using the freely available life-history database PanTHERIA.
3. Moreover, we explore how existing biases influence results of comparative analyses of extinc- tion risk by using subsets of data that attempt to correct for detected biases. In particular, we focus on links between four species’ traits commonly linked to vulnerability (distribution range area, adult body mass, population density and gestation length) and conduct univariate and multivari- ate analyses to understand how biases affect model predictions.
4. Our results show important biases in data availability with c.22% of mammals completely lack- ing data. Missing data, which appear to be not missing at random, occur frequently in all traits (14–99% of cases missing). Data availability is explained by intrinsic traits, with larger mammals occupying bigger range areas being the best studied. Importantly, we find that existing biases affect the results of comparative analyses by overestimating the risk of extinction and changing which traits are identified as important predictors.
5. Our results raise concerns over our ability to draw general conclusions regarding what makes a species more prone to extinction. Missing data represent a prevalent problem in comparative anal- yses, and unfortunately, because data are not missing at random, conventional approaches to fill data gaps, are not valid or present important challenges. These results show the importance of making appropriate inferences from comparative analyses by focusing on the subset of species for which data are available. Ultimately, addressing the data bias problem requires greater investment in data collection and dissemination, as well as the development of methodological approaches to effectively correct existing biases.Peer reviewe
ПЕРШИЙ ЮВІЛЕЙ КАТЕРИНОСЛАВА ЯК ІСТОРІОГРАФІЧНЕ ЯВИЩЕ
У статті здійснена спроба вивчення історіографічного процесу у регіональному вимірі на прикладі Катеринослава.The article deals with the investigation of historiographic process in the second of XIX – at the beginning of ХХ century in a regional view on the materials of Katerinoslav
ДУБ М.ЗАЛІЗНЯКА: З ІСТОРІЇ ПАМ’ЯТКООХОРОННОЇ РОБОТИ
Стаття присвячена проблемі вивчення, охорони та збереження пам’ятки природи тисячолітнього дуба М.Залізняка. В ній розглядаються етапи дослідження вікового дерева, основні пам’яткоохоронні заходи, проведені для підтримки його життєдіяльностіThis article is about a problem of investigation, saving and protection the monument of nature the millennial oak of M.Zaliznyak. It describes about the stages of research of the tree, the main protection measures in order to obtain it activit
Проект пункта шиномонтажного участка с конструктивной разработкой устройства для измерения биений шин и ободьев колес в условиях ИП Русанова
В разделе объект и методы исследования выполнен аналитический обзор по теме работы и обоснован выбор темы выпускной работы бакалавра.
В разделе расчеты и аналитика представлены необходимые инженерные расчеты, связанные с организацией работ по разработке шиномонтажного участка с конструктивной разработкой устройства для измерения биений шин и ободьев колёс.In the object and research methods section, an analytical review is carried out on the topic of work and the choice of the theme of the final work of the bachelor is substantiated.
The section of calculations and analytics presents the necessary engineering calculations related to the organization of work on the development of the tire section with the constructive development of a device for measuring the runout of tires and wheel rims
Влияние температурного градиента на спектр дифрагированного рентгеновского излучения в кристалле кварца
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