26 research outputs found
Люминесценция кристаллов с оксианионами и оксидных стекол при возбуждении импульсами потока электронов: диссертация на соискание учёной степени доктора физико-математических наук: спец. 01.04.07
Датчик угла шарового гироскопа
При работе с гироскопическим прибором, важнейшим информационным параметром является угловое положение оси вращения ротора, относительно корпуса прибора. Существует много различных способов съема угловой информации, подходящих под ту или иную задачу. В первую очередь, для выбора принципа работы датчика, требуется изучить конструкцию прибора, на котором будет установлен датчик угла (ДУ), и установить требования, согласно которым будет разрабатываться датчик угла.
В данной работе требуется рассмотреть всевозможные типа оптических датчиков, подобрать наиболее подходящий тип, и провести исследование по возможному использованию данного датчика на имеющейся конструкции гироскопического прибора с газодинамической подвесом шарового ротора.When working with a gyro instrument, the most important information parameter is the angular position of the axis of rotation of the rotor, relative to the body of the device. There are many different ways to remove the angular information, suitable for a particular task. First of all, to select the principle of the sensor, it is required to study the design of the device on which the angle sensor will be installed and establish the requirements according to which the angle sensor will be developed.
In this paper, it is required to consider all possible types of optical sensors, to select the most suitable type, and to conduct a study on the possible use of this sensor on the existing design of a gyroscopic device with a gas-dynamic suspension of a spherical rotor
Biotic predictors complement models of bat and bird responses to climate and tree diversity in European forests
Bats and birds are key providers of ecosystem services in forests. How climate and habitat jointly shape their communities is well studied, but whether biotic predictors from other trophic levels may improve bird and bat diversity models is less known, especially across large bioclimatic gradients. Here, we achieved multi-taxa surveys in 209 mature forests replicated in six European countries from Spain to Finland, to investigate the importance of biotic predictors (i.e., the abundance or activity of defoliating insects, spiders, earthworms and wild ungulates) for bat and bird taxonomic and functional diversity. We found that 9 out of 12 bird and bat diversity metrics were best explained when biotic factors were added to models including climate and habitat variables, with a mean gain in explained variance of 38% for birds and 15% for bats. Tree functional diversity was the most important habitat predictor for birds, while bats responded more to understorey structure. The best biotic predictors for birds were spider abundance and defoliating insect activity, while only bat functional evenness responded positively to insect activity. Accounting for potential biotic interactions between bats, birds and other taxa of lower trophic levels will help to understand how environmental changes along large biogeographical gradients affect higher-level predator diversity in forest ecosystems
Which Factors Determine Our Online Social Capital? An Analysis Based on Structural Equation Modelling
The relationship between social network sites and social capital has received much research attention. However, two research gaps can be identified in the existing literature. First, only few studies have examined online social capital as a resource in online social networks. In this regard, it is not clear how to validly measure online social capital. Second, while the factors influencing social capital, among them properties of an individual’s social network, have been investigated in offline settings, such factors have not yet been investigated in terms of online social capital. Addressing these gaps, we asked 1000 Facebook users to provide information on their Facebook usage and online friendship network. Employing structural equation modelling for analysing the survey data, we show that Williams’ Internet Social Capital Scales, which are commonly used to assess social capital in offline settings, can be used to validly measure online social capital. Moreover, we find that some of the variables influencing offline social capital, among them similarity in terms of sociodemographic attributes, seem less important in an online setting
Los Presupuestos de Gastos Tributarios: Conceptos y Desafíos de Implementación
Los gastos tributarios son generalmente definidos como aquellos gastos del gobierno realizados por medio de disposiciones de la legislación tributaria, reglamentos y práctica que reducen o postergan el impuesto para una parte de los contribuyentes. Hay una preocupación general de que los gastos tributarios tienen efectos negativos en las políticas tributaria y presupuestaria, con efectos sobre la transparencia, eficiencia y equidad de los sistemas fiscales. Muchos países de Latinoamérica y unos pocos del Caribe ya hacen estimativas de sus gastos tributarios, pero en muchos casos sin adoptar una metodología consistente que permita comparaciones adecuadas, o mismo evaluar su efectividad. Este Documento de Trabajo discute los aspectos conceptuales de los gastos tributarios, los principales desafíos para estimarlos, y los procedimientos generalmente adoptados en los países de la OCDE y de Latinoamérica para su cálculo, presentación y aprobación.
Los Presupuestos de Gastos Tributarios: Conceptos y Desafíos de Implementación
Los gastos tributarios son generalmente definidos como aquellos gastos del gobierno realizados por medio de disposiciones de la legislación tributaria, reglamentos y práctica que reducen o postergan el impuesto para una parte de los contribuyentes. Hay una preocupación general de que los gastos tributarios tienen efectos negativos en las políticas tributaria y presupuestaria, con efectos sobre la transparencia, eficiencia y equidad de los sistemas fiscales. Muchos países de Latinoamérica y unos pocos del Caribe ya hacen estimativas de sus gastos tributarios, pero en muchos casos sin adoptar una metodología consistente que permita comparaciones adecuadas, o mismo evaluar su efectividad. Este Documento de Trabajo discute los aspectos conceptuales de los gastos tributarios, los principales desafíos para estimarlos, y los procedimientos generalmente adoptados en los países de la OCDE y de Latinoamérica para su cálculo, presentación y aprobación.Sector financiero, Economía :: Política fiscal, Tributación, Subsidios, Política Fiscal
Tax Expenditure Budgets: Concepts and Challenges for Implementation
Tax expenditures are generally defined as those government expenditures carried out through tax legislation, regulations, and practices that reduce or defer taxes for some taxpayers. There is a general concern that the tax expenditures negatively affect the budget and tax policies, which in turn affect the transparency, efficiency, and equality of the fiscal systems. Many countries in Latin American and a few in the Caribbean already estimate their tax expenditures; but in many cases they do so without adopting a consistent methodology that allows for adequate comparisons or that even evaluates their effectiveness. This working paper discusses the conceptual aspects of tax expenditures, the main challenges to assess them, and the general procedures adopted in the OECD countries and Latin America and the Caribbean to calculate, present, and approve them.Financial Sector, Economics :: Fiscal Policy, Taxation, Subsidies and Fiscal Policy, expenditure budgets, tax expenditure budgets
Trust in Virtual Teams: A Multidisciplinary Review and Integration
Organizations have increasingly turned to the use of virtual teams (VTs) to tackle the complex nature of today’s organizational issues. To address these practical needs, VTs researchers from different disciplines have begun to amass a large literature. However, the changing workplace that is becoming so reliant on VTs comes with its own set of management challenges, which are not sufficiently addressed by current research on VTs. Paradoxically, despite the challenges associated with technology in terms of its disruption to trust development in VTs, trust is one of the most promising solutions for overcoming myriad problems. Though the extant literature includes an abundance of studies on trust in VTs, a comprehensive multidisciplinary review and synthesis is lacking. Addressing this gap, we present a systematic theoretical review of 124 articles from the disparate, multidisciplinary literature on trust in VTs. We use the review to develop an integrated model of trust in VTs. Based on our review, we provide theoretical insights into the relationship between virtuality and team trust, and highlight several critical suggestions for moving this literature forward to meet the needs of workplaces of the future, namely: better insight into how trust evolves alongside the team’s evolution, clarity about how to adequately conceptualize and operationalize virtuality, and greater understanding about how trust might develop differently across diverse types of virtual contexts with various technology usages. We conclude with guidelines for managing VTs in the future workplace, which is increasingly driven and affected by changing technologies, and highlight important trends to consider