323,654 research outputs found
EFFECTS OF THE S-ADENOSYLHOMOCYSTEINE HYDROLASE INHIBITORS 3-DEAZAADENOSINE AND 3-DEAZAARISTEROMYCIN ON RNA METHYLATION AND SYNTHESIS
No full textThe effects of 3-deazaaristeromycin and 3-deazaadenosine on RNA methylation and synthesis were examined in the mouse macrophage cell line, RAW264. S-Adenosylhomocysteine accumulated in cells incubated with 3-deazaaristeromycin while S-3-deazaadenosylhomocysteine was the major product in cells incubated with 3-deazaadenosine and homocysteine thiolactone. RNA methylation was inhibited to a similar extent by the accumulation of either S-adenosylhomocysteine or S-3-deazaadenosylhomocysteine, with S-adenosylhomocysteine being a slightly better inhibitor. In mRNA, the synthesis of N6-methyladenosine and N6-methyladenosine and N6-methyl-2'-O-methyladenosine were inhibited to the greatest extent, while the synthesis of 7-methylguanosine and 2'-O-methyl nucleosides were inhibited to a lesser extent. Incubation of cells with 100 μM 3-deazaaristeromycin or with 10 μM 3-deazaadenosine and 50 μM homocysteine thiolactone produced little inhibition of mRNA synthesis, even though mRNA methylation was inhibited. In contrast, mRNA synthesis was greatly inhibited by treatment of cells with 100 μM 3-deazaadenosine and the inhibition of synthesis was not correlated with an inhibition of methylation
Oskar Backlund: The Eleventh Bruce Medalist
No full textThe Pulkovo Observatory, established by Czar Nicholas I in the 1830s, served the needs of the Russian empire just as the Royal Greenwich Observatory, the Paris Observatory, and the U.S. Naval Observatory served their own governments. In the nineteenth century every great power needed astronomers to furnish accurate time, provide precise almanacs for navigators, and help map the Earth.Published by and copyright by the Astronomical Society of the Pacific.Tenn, Joseph S.. 1991. Oskar Backlund: The Eleventh Bruce Medalist, Mercury 20: 175
Backlund (O.). — Ueber die Bestimmung der Glieder langer Perioden mit besonderer Rücksicht auf die kleinen Planeten der Hecubagruppe. Backlund (O.). — Ueber eine horistische Differential gleichung Gyldéns. (Extraits du Bulletin de l’Académie de Saint-Pétersbourg, n°s 1 et 3, 1902.)
No full textCallandreau Octave. Backlund (O.). — Ueber die Bestimmung der Glieder langer Perioden mit besonderer Rücksicht auf die kleinen Planeten der Hecubagruppe. Backlund (O.). — Ueber eine horistische Differential gleichung Gyldéns. (Extraits du Bulletin de l’Académie de Saint-Pétersbourg, n°s 1 et 3, 1902.). In: Bulletin astronomique, tome 19, 1902. p. 471
APPLICATION OF A BACKLUND TRANSFORMATION IN NONLINEAR ELASTODYNAMICS. TWO-PULSE INTERACTION
No full textA Backlund transformation is used to construct a class of model nonlinear
stress-strain laws which admit an interior change of concavity. Application is
made to analyse two-pulse interaction in the model nonlinear elastic materials
BACKLUND-TRANSFORMATIONS FOR HARMONIC MAPS IN 2 INDEPENDENT VARIABLES
No full textBacklund transformations for harmonic maps are described as the action of the structure group on harmonic one-forms or as gauge transformations of the soliton connection constructed via embedding the configuration manifold into a flat space. As an illustration, Baicklund transformations for maps from M2 to the Poincare upper half-plane and for maps determining stationary vacuum gravitational fields with axial symmetry are obtained
Connection between the infinite sequence of Lie-Backlund symmetries of the Korteweg-de Vries and sine-Gordon equations
No full textFrom the observation that the infinite sequence of Lie-Backlund symmetries of the potential modified Kortweg-deVries (PMK-dV) and the sine-Gordon (s-G) equations are identical, it is shown that there exists a simple connection between the Lie-Backlund symmetries (written in the form of evolution equations) of the Korteweg-deVries (K-dV) and s-G equations. Further, this connection is similar to the one obtained by Chodos for the conserved quantities of K-dV and s-G equations. We also point out that the result of Chodos can be realized from the equality of conserved densities of PMK-dV and s-G systems
Barriers to Industrial Energy Efficiency in Foundries: a European Comparison
No full textAccording to recent studies, the 20% European improvement in energy efficiency will not be achieved with current trends, even with the adoption of present policies to reduce primary energy use. This is due to the existence of several barriers that hinder the adoption of the energy-efficient technologies and practices. A relevant contribution to improved energy efficiency could come from the industrial sector, due to its relevance on total energy use. This study therefore addresses barriers within the European foundry industry, a major industrial energy user and a strategic player for the European economy. The research investigates the barriers to energy efficiency at 65 foundries, several of them small and medium-sized enterprises (SMEs), highlighting the critical problems and difficulties by evaluating the socio-technical frameworks against which the barriers have been categorized. Findings show that the greatest perceived barriers are the perception of the lack of resources to be devoted to improving energy efficiency, and the existence of other priorities such as the importance of guaranteeing business continuity. The study has also performed a preliminary analysis of the factors that might affect the perception of barriers. In particular, looking at size, smaller enterprises show a greater perception of the barriers than larger ones, mainly due to several organizational issues, but with effect on behavioural ones, that tend to downgrade energy efficiency to a peripheral issue. The study has also highlighted differences by type of alloy characterizing foundries, taken as proxy of the process complexity. Indeed, enterprises with simpler production processes tend to perceive higher barriers to energy efficiency, showing the need to identify effective means to promote energy efficiency among those enterprises. Moreover, the analysis has pointed out that performing energy audits brings more awareness to the enterprises, highlighting the effective existing difficulties in improving their energy efficiency. This result seems to be relevant since it shows the need for the research to analyze the awareness to energy efficiency in greater depth and develop the most effective policies to increase it at industrial level. Finally when looking at the country in which foundries operate, German enterprises tend to suffer from the barriers far less than the average, whilst a totally different behaviour can be observed for Swedish ones. These preliminary findings open the research to investigate in greater depth the factors leading to a different perception of barriers, and also the domestic policies that have led to those results. Moreover, the study opens to investigate which means, i.e. drivers, might be more effectively exploited at European level to promote industrial energy efficiency
Beyond Barriers – A Case Study on Driving Forces for Improved Energy Efficiency in the Foundry Industries in Finland, France, Germany, Italy, Poland, Spain, and Sweden
No full textEnergy management plays an important role in the transformation of industrial energy systems towards improved energy efficiency and increased sustainability. This paper aims to study driving forces for improved energy efficiency in some European energy-intensive foundry industries. The investigation has been conducted as a multiple case study involving 65 foundries located in Finland, France, Germany, Italy, Poland, Spain, and Sweden. The most relevant perceived driving forces were found to be financially related, followed by organizational driving forces. Nevertheless, some differences can be appreciated according to the firm's size and country. Almost half of the studied foundries lack a long-term energy strategy, about one-fourth stated that they have used Energy Performance Contracting (EPC), and only approximately one in ten foundries have used Third Party Financing (TPF). Among the studied foundries, three out of five have conducted an energy audit. On average, the energy saving potential according to the respondents is stated to be 7.5%. In conclusion, energy management in the European foundry industry, despite increasing energy prices and extensive energy policy actions taken by the EU, still seems to have great improvement potential, calling for future research and policy actions in the field
Backlund transformations for many-body systems related to KdV
No full textWe present Backlund transformations (BTs) with parameter for certain classical integrable n-body systems, namely the many-body generalised Henon-Heiles, Garnier and Neumann systems. Our construction makes use of the fact that all these systems may be obtained as particular reductions (stationary or restricted flows) of the KdV hierarchy; alternatively they may be considered as examples of the reduced sl(2) Gaudin magnet. The BTs provide exact time-discretizations of the original (continuous) systems, preserving the Lax matrix and hence all integrals of motion, and satisfy the spectrality property with respect to the Backlund parameter
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