755 research outputs found
Short term synaptic depression model—Analytical solution and analysis
In this article we present analytical solutions of the single and pair pulse time evolution of a plastic neocortical synapse described by the TM-model. We show that this model is equivalent to the receptor-desensitization model with three kinetic states. For the TM-model we derive the analytical form of a measure of paired pulse depression. We analyze the sensitivity of the synaptic depression phenomenon on model parameters and derive the relative importance of each of the parameters. The closed form of the measure of synaptic depression allows fitting the model to experimental data. The fitted parameters are used to make predictions about the asymptotic properties of the postsynaptic currents. We show that for synapses with the ratio of inactivation and recovery rates of the same order, the synaptic depression does not preclude the rate-coding of information: e.g. in the pyramid–pyramid connections of adult rat neocortex, rate-coding is possible for higher frequencies
The effectiveness of green certificates - evidence from Poland
The paper examines the role of technological and institutional lock-in as a barrier to more sustainable innovation in the energy sector, and the implications of this to for determining appropriate policy responses. The paper, with theoretical input from path-dependency, technology and carbon lock-in as well as innovation effect of deployment policies, presents a qualitative study of the factors that influenced the evolution of tradable green certificates in Poland.The path dependency has been reinforced by the lock-in mechanisms: economies of scale, economies of scope, network externalities and informational increasing returns. Hence, the characteristics of current regime set the conditions for the development of new transition pathways. The incumbent socio-technical regime is not just fossil-based, but may also include mature niches specialised in the exploitation of renewable sources. This implies a need to distinguish between lock-in mechanisms favouring the old fossil-based regime, well-established (mature) renewable energy niches, or new pathways. It also provides the justification for intervention in the process of technology diffusion: the greater ability of the state to coordinate technological choices undertaken in the frame of market mechanism.У статті розглядається роль технологічного та інституційного «блокування вуглецю» в якості бар'єру для впровадження інновацій в енергетичному секторі, які сприяють сталому розвитку, з подальшим визначенням і пропозицією адекватних політичних заходів. Проаналізовано взаємодію чинника «блокування вуглецю» та чинників інноваційного сталого розвитку в контексті соціально-технічних і технологічних трансформацій. Дано рекомендації, що передбачають внесення змін і доповнень до нормативно-регуляторної бази (на прикладі Польщі), відповідно до сучасних вимог ринкової системи, що забезпечують ефективне функціонування останньої, за умови прагнення досягнення поставлених стратегічних цілей сталого економічного розвитку.В статье рассматривается роль технологической и институциональной «блокировки углерода» в качестве барьера для внедрения инноваций в энергетическом секторе, способствующих устойчивому развитию, с последующим определением и предложением адекватных политических мер. Проанализировано взаимодействие фактора «блокировки углерода» и факторов инновационного устойчивого развития в контексте социально-технических и технологических трансформаций. Даны рекомендации, предусматривающие внесение изменений и дополнений в нормативно-регуляторную базу (на примере Польши), в соответствии с современными требованиями рыночной системы, обеспечивающими эффективное функционирования последней, при условии стремления достижения поставленных стратегических целей устойчивого экономического развития
Method and Apparatus for Water Jet Drilling of Rock
Rock drilling method and apparatus utilizing high pressure water jets for drilling holes of relatively small diameter at speeds significantly greater than that attainable with existing drilling tools. Greatly increased drilling rates are attained due to jet nozzle geometry and speed of rotation. The jet nozzle design has two orifices, one pointing axially ahead in the direction of travel and the second inclined at an angle of approximately 30° from the axis. The two orifices have diameters in the ratio of approximately 1:2. Liquid jet velocities in excess of 1,000 ft/sec are used, and the nozzle is rotated at speeds up to 1,000 rpm and higher
Combating Energy Poverty in the Social Housing Stock
The authors of this publication indicate that in the second decade of the 21st century European Union institutions have been aiming at encompassing social housing construction into a common climate and energy policy. It has been shown that the justification of public support for energy investments in the social housing stock is an attempt to counteract climate changes, reduce energy poverty among low-income households as well as to promote local workplaces and economic development in a given area. The cohesion policy of the European Union may actively contribute to strengthening its dynamics and ensure a leverage effect which in turn will lead to the use of other, additional sources of finance. In accordance with the guidelines of the European Commission, the housing stock has been qualified to be subject to support from structural funds in the new financial perspective until 2020, especially in terms of thermomodernisation and promotion of renewable sources of energy, integrated actions aiming at developing urban areas and combating exclusion by providing access to dwellings to marginalised communities and offering high quality, affordable social services.Автори цієї публікації вказують, що в другому десятилітті XXI століття інститути ЄС націлені на енергетичну політику в побуті і її вплив на загальний клімат. Показана виправданість громадської підтримки інвестицій в економію енергії в побуті як спроба нейтралізувати зміни клімату, скоротити бідність серед сімей з низьким рівнем доходу і, щоб просувати місцеві робочі місця і економічний розвиток в цій області. Єдина політика Євросоюзу активно сприяє зміцненню його динаміки і гарантує ефект важеля, який у свою чергу призводитиме до використання інших, додаткових джерел фінансування. Відповідно до директив Єврокомісії, житлова сфера була кваліфікована, як така що підлягає підтримці від структурних фондів в новій фінансовій перспективі до 2020 р., особливо в термінах термомодернізації і просування поновлюваних джерел енергії. Але він доки не об'єднав дії, що націлюють розвиток міст на боротьбу за економію енергоресурсів, забезпечення доступу до житла маргіналізованим суспільствам і пропозицію соціальних послуг високої якості.Авторы этой публикации указывают, что во втором десятилетии XXI столетия институты ЕС нацелены на энергетическую политику в быту и ее влияние на общий климат. Показана оправданность общественной поддержки инвестиций в экономию энергии в быту как попытка нейтрализовать изменения климата, сократить бедность среди семей с низким уровнем дохода и, чтобы продвигать местные рабочие места и экономическое развитие в данной области. Единая политика Евросоюза активно содействует укреплению его динамики и гарантирует эффект рычага, который будет в свою очередь приводить к использованию других, дополнительных источников финансирования. В соответствии с директивами Еврокомиссии, жилищная сфера была квалифицирована, как подлежащая поддержке от структурных фондов в новой финансовой перспективе до 2020 г., особенно в терминах термомодернизации и продвижения возобновляемых источников энергии. Но он пока не объединил действия, нацеливающие развитие городов на борьбу за экономию энергоресурсов, обеспечение доступа к жилью маргинализированным обществам и предложение социальных услуг высокого качества
High-energy-low-temperature technologies for the synthesis of nanoparticles: Microwaves and high pressure
Microwave Solvothermal Synthesis (MSS) is a chemical technology, where apart from possible effects of microwaves on the chemical reaction paths, microwave heating allows the precise planning of a time-temperature schedule, as well as to achieve high super-saturation of the reagents uniformly in the reactor vessel. Thus, MSS is suitable for production of nanoparticles with small grain size distribution and a high degree of crystallinity. A further advantage of the technology is a much lower synthesis temperature than for gas phase, plasma or sol-gel technologies. New reactors have been developed to exploit these advantages of the MSS technology of nanoparticles synthesis and to scale up the production rate. Reactor design and realization has been shown to be decisive and critical for the control of the MSS technology. Examples of oxidic and phosphatic nanoparticles synthesis have been reported
A Framework to Synergize Partial Order Reduction with State Interpolation
We address the problem of reasoning about interleavings in safety
verification of concurrent programs. In the literature, there are two prominent
techniques for pruning the search space. First, there are well-investigated
trace-based methods, collectively known as "Partial Order Reduction (POR)",
which operate by weakening the concept of a trace by abstracting the total
order of its transitions into a partial order. Second, there is state-based
interpolation where a collection of formulas can be generalized by taking into
account the property to be verified. Our main contribution is a framework that
synergistically combines POR with state interpolation so that the sum is more
than its parts
NAP1 Modulates Binding of Linker Histone H1 to Chromatin and Induces an Extended Chromatin Fiber Conformation
NAP1 (nucleosome assembly protein 1) is a histone chaperone that has been described to bind predominantly to the histone H2A·H2B dimer in the cell during shuttling of histones into the nucleus, nucleosome assembly/remodeling, and transcription. Here it was examined how NAP1 interacts with chromatin fibers isolated from HeLa cells. NAP1 induced a reversible change toward an extended fiber conformation as demonstrated by sedimentation velocity ultracentrifugation experiments. This transition was due to the removal of the linker histone H1. The H2A·H2B dimer remained stably bound to the native fiber fragments and to fibers devoid of linker histone H1. This was in contrast to mononucleosome substrates, which displayed a NAP1-induced removal of a single H2A·H2B dimer from the core particle. The effect of NAP1 on the chromatin fiber structure was examined by scanning/atomic force microscopy. A quantitative image analysis of ∼36,000 nucleosomes revealed an increase of the average internucleosomal distance from 22.3 ± 0.4 to 27.6 ± 0.6 nm, whereas the overall fiber structure was preserved. This change reflects the disintegration of the chromatosome due to binding of H1 to NAP1 as chromatin fibers stripped from H1 showed an average nucleosome distance of 27.4 ± 0.8 nm. The findings suggest a possible role of NAP1 in chromatin remodeling processes involved in transcription and replication by modulating the local linker histone content
Effect of Nb and Ti micro-additives and thermo-mechanical treatment of high-manganese steels with aluminium and silicon on their microstructure and mechanical properties
The r esults are based on two experimental high-manganese X98MnAlSiNbTi24-11 and X105MnAlSi24-11 steels subjected
to thermo-mechanical treatment by hot-rolling on a semi-industrial processing line. The paper presents the results of diffraction and
structural studies using scanning and transmission electron microscopy showing the role of Nb and Ti micro-additives in shaping
high strength properties of high-manganese austenitic-ferritic steels with complex carbides. The performed investigations of two
experimental steels allow to explain how the change cooling conditions after thermo-mechanical treatment of the analysed steels
affects the change of their microstructure and mechanical properties. The obtained results allow assessing the impact of both the
chemical composition and the applied thermo-mechanical treatment technology on the structural effects of strengthening of the
newly developed steels
Multiple Pulsejet Boring Device
A method and device for boring a hole [5] through a material along a desired path includes an umbilical subsystem [2000] connected to a boring subsystem [3000] having a plurality of pulsejets [3100]. These pulsejets [3100] repeatedly receive and ignite a combustible fluid [7] in a combustion chamber [3230] causing a portion of the fluid [7] to be forced out of a nozzle [3260] at high speeds as a fluid slug [10] that impacts materials ahead of the pulsejet [3100]. A controller [3310] controls the amount of fluid provided to each pulsejet [3100], and the firing timing, thereby controlling the intensity in which each slug [10] impacts the material. By modulating the intensity and firing sequence of each of the pulsejets [3100], material ahead of the boring subsystem [3000] is differentially bored thereby allowing steering of the boring subsystem [3000]
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