1,270 research outputs found

    Влияние неоднородностей температуры поверхности на теплообмен воздуха с Землей

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    В работе проведено моделирование процесса натекания воздуха с холодной поверхности воды на теплую поверхность суши и сравнение расчетов с результатами измерений. Из расчетов следует, что потоки тепла в прибрежной зоне могут более чем на 20% превышать значения потоков тепла, вычисленных из предположения о горизонтальной однородности приземного слоя. Таким образом, горизонтальную неоднородность атмосферы следует учитывать при расчетах охлаждения водоемов, горизонтальный размер которых имеет масштаб ~100 м.В роботі проведено моделювання процесу натікання повітря з холодної поверхні води на теплу поверхню суші та порівняння розрахунків із вимірюваннями. З розрахунків видно, що потоки тепла в прибережній зоні можуть більш ніж на 20% перевищувати значення потоків тепла, обчислених з припущення про горизонтальну однорідність приземного шару. Таким чином, горизонтальну неоднорідність атмосфери слід враховувати при розрахунках охолодження водойм, горизонтальний розмір яких має масштаб ~100 м.In the paper, the air flow process from the cold water surface onto the warm land surface was simulated. The comparisons of calculations with measurements were performed as well. The calculations show that the heat flux in the narrow coastal zone may be more than 20% higher than the values of heat fluxes calculated from the assumption of horizontal homogeneity of the surface layer. Thus, the horizontal inhomogeneity of the atmosphere must be taken into account in the calculation of the cooling water, the horizontal size of which has a scale of ~100 m

    Net neutrality discourses: comparing advocacy and regulatory arguments in the United States and the United Kingdom

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    Telecommunications policy issues rarely make news, much less mobilize thousands of people. Yet this has been occurring in the United States around efforts to introduce "Net neutrality" regulation. A similar grassroots mobilization has not developed in the United Kingdom or elsewhere in Europe. We develop a comparative analysis of U.S. and UK Net neutrality debates with an eye toward identifying the arguments for and against regulation, how those arguments differ between the countries, and what the implications of those differences are for the Internet. Drawing on mass media, advocacy, and regulatory discourses, we find that local regulatory precedents as well as cultural factors contribute to both agenda setting and framing of Net neutrality. The differences between national discourses provide a way to understand both the structural differences between regulatory cultures and the substantive differences between policy interpretations, both of which must be reconciled for the Internet to continue to thrive as a global medium

    Net neutrality discourses: comparing advocacy and regulatory arguments in the United States and the United Kingdom

    Get PDF
    Telecommunications policy issues rarely make news, much less mobilize thousands of people. Yet this has been occurring in the United States around efforts to introduce "Net neutrality" regulation. A similar grassroots mobilization has not developed in the United Kingdom or elsewhere in Europe. We develop a comparative analysis of U.S. and UK Net neutrality debates with an eye toward identifying the arguments for and against regulation, how those arguments differ between the countries, and what the implications of those differences are for the Internet. Drawing on mass media, advocacy, and regulatory discourses, we find that local regulatory precedents as well as cultural factors contribute to both agenda setting and framing of Net neutrality. The differences between national discourses provide a way to understand both the structural differences between regulatory cultures and the substantive differences between policy interpretations, both of which must be reconciled for the Internet to continue to thrive as a global medium

    Current-Density Functional Theory of the Response of Solids

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    The response of an extended periodic system to a homogeneous field (of wave-vector q=0q=0) cannot be obtained from a q=0q=0 time-dependent density functional theory (TDDFT) calculation, because the Runge-Gross theorem does not apply. Time-dependent {\em current}-density functional theory is needed and demonstrates that one key ingredient missing from TDDFT is the macroscopic current. In the low-frequency limit, in certain cases, density polarization functional theory is recovered and a formally exact expression for the polarization functional is given.Comment: 5 pages, accepted in PR

    Towards Independent Particle Reconstruction from Cryogenic Transmission Electron Microscopy

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    Coronary heart disease is the single largest killer of Americans so improved means of detecting risk factors before arterial obstructions appear are expected to lead to a improvement in quality of life with a reduced cost. This paper introduces a new approach to 3-D reconstruction of individual particles based on statistical modeling from a sparse set of 2-D projection images. This paper introduces a new approach to 3-D reconstruction of individual particles based on statistical modeling from a sparse set of 2-D projection images. The method is in contrast to the current state of practice where reconstruction is performed via signal processing or Bayesian methods that use averaged images acquired from an ensemble of particles. As such, this new approach has its impetus in use for novel diagnostic tests such as LDL and HDL particle shape characterization. The approach is also expected to have uses in areas such as quality assurance for drug delivery nano-technologies and for general proteomic studies. The individual particle reconstruction algorithm is based on a hidden Markov model. Higher order Markov chain statistics, which are generated from the a priori model of the target of interest, can be derived from traditional methods such as single particle reconstruction and/or the underlying physical properties of the particle. By placing the reconstruction voxel space at a 45° angle to the projection image, 4-passes of the HMM processing can be performed from a single image. Reconstruction results from a simple model and a single projection image resulted in better than 98% reconstruction accuracy as compared to the original target

    Salience-based selection: attentional capture by distractors less salient than the target

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    Current accounts of attentional capture predict the most salient stimulus to be invariably selected first. However, existing salience and visual search models assume noise in the map computation or selection process. Consequently, they predict the first selection to be stochastically dependent on salience, implying that attention could even be captured first by the second most salient (instead of the most salient) stimulus in the field. Yet, capture by less salient distractors has not been reported and salience-based selection accounts claim that the distractor has to be more salient in order to capture attention. We tested this prediction using an empirical and modeling approach of the visual search distractor paradigm. For the empirical part, we manipulated salience of target and distractor parametrically and measured reaction time interference when a distractor was present compared to absent. Reaction time interference was strongly correlated with distractor salience relative to the target. Moreover, even distractors less salient than the target captured attention, as measured by reaction time interference and oculomotor capture. In the modeling part, we simulated first selection in the distractor paradigm using behavioral measures of salience and considering the time course of selection including noise. We were able to replicate the result pattern we obtained in the empirical part. We conclude that each salience value follows a specific selection time distribution and attentional capture occurs when the selection time distributions of target and distractor overlap. Hence, selection is stochastic in nature and attentional capture occurs with a certain probability depending on relative salience

    World radiocommunication conference 12 : implications for the spectrum eco-system

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    Spectrum allocation is once more a key issue facing the global telecommunications industry. Largely overlooked in current debates, however, is the World Radiocommunication Conference (WRC). Decisions taken by WRC shape the future roadmap of the telecommunications industry, not least because it has the ability to shape the global spectrum allocation framework. In the debates of WRC-12 it is possible to identify three main issues: enhancement of the international spectrum regulatory framework, regulatory measures required to introduce Cognitive Radio Systems (CRS) technologies; and, additional spectrum allocation to mobile service. WRC-12 eventually decided not to change the current international radio regulations with regard to the first two issues and agreed to the third issue. The main implications of WRC-12 on the spectrum ecosystem are that most of actors are not in support of the concept of spectrum flexibility associated with trading and that the concept of spectrum open access is not under consideration. This is explained by the observation that spectrum trading and spectrum commons weaken state control over spectrum and challenge the main principles and norms of the international spectrum management regime. In addition, the mobile allocation issue has shown the lack of conformity with the main rules of the regime: regional spectrum allocation in the International Telecommunication Union (ITU) three regions, and the resistance to the slow decision making procedures. In conclusion, while the rules and decision-making procedures of the international spectrum management regime were challenged in the WRC-12, the main principles and norms are still accepted by the majority of countries

    Logics, thresholds, strategic power, and the promotion of liberalisation by governments: a case study from British Higher Education

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    Liberalisation has become an increasingly important policy trend, both in the private and public sectors of advanced industrial economies. This article eschews deterministic accounts of liberalisation by considering why government attempts to institute competition may be successful in some cases and not others. It considers the relative strength of explanations focusing on the institutional context, and on the volume and power of sectoral actors supporting liberalisation. These approaches are applied to two attempts to liberalise, one successful and one unsuccessful, within one sector in one nation – higher education in Britain. Each explanation is seen to have some explanatory power, but none is sufficient to explain why competition was generalised in the one case and not the other. The article counsels the need for scholars of liberalisation to be open to multiple explanations which may require the marshalling of multiple sources and types of evidence
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