184 research outputs found
Adiabatic times for Markov chains and applications
We state and prove a generalized adiabatic theorem for Markov chains and
provide examples and applications related to Glauber dynamics of Ising model
over Z^d/nZ^d. The theorems derived in this paper describe a type of adiabatic
dynamics for l^1(R_+^n) norm preserving, time inhomogeneous Markov
transformations, while quantum adiabatic theorems deal with l^2(C^n) norm
preserving ones, i.e. gradually changing unitary dynamics in C^n
Metal hydride hydrogen storage tank for fuel cell utility vehicles
The “low-temperature” intermetallic hydrides with hydrogen storage capacities below 2 wt% can provide compact H2 storage simultaneously serving as a ballast. Thus, their low weight capacity, which is usually considered as a major disadvantage to their use in vehicular H2 storage applications, is an advantage for the heavy duty utility vehicles. Here, we present new engineering solutions of a MH hydrogen storage tank for fuel cell utility vehicles which combines compactness, adjustable high weight, as well as good dynamics of hydrogen charge/discharge. The tank is an assembly of several MH cassettes each comprising several MH containers made of stainless steel tube with embedded (pressed-in) perforated copper fins and filled with a powder of a composite MH material which contains AB2- and AB5-type hydride forming alloys and expanded natural graphite. The assembly of the MH containers staggered together with heating/cooling tubes in the cassette is encased in molten lead followed by the solidification of the latter. The tank can provide >2 h long H2 supply to the fuel cell stack operated at 11 kWe (H2 flow rate of 120 NL/min). The refuelling time of the MH tank (T = 15–20 °C, P(H2) = 100–150 bar) is about 15–20 min
Nature of Fast Relaxation Processes and Spectroscopy of a Membrane-Active Peptide Modified with Fluorescent Amino Acid Exhibiting Excited State Intramolecular Proton Transfer and Efficient Stimulated Emission
A fluorescently labeled peptide that exhibited fast excited state intramolecular proton transfer (ESIPT) was synthesized, and the nature of its electronic properties was comprehensively investigated, including linear photophysical and photochemical characterization, specific relaxation processes in the excited state, and its stimulated emission ability. The steady-state absorption, fluorescence, and excitation anisotropy spectra, along with fluorescence lifetimes and emission quantum yields, were obtained in liquid media and analyzed based on density functional theory quantum-chemical calculations. The nature of ESIPT processes of the peptide’s chromophore moiety was explored using a femtosecond transient absorption pump-probe technique, revealing relatively fast ESIPT velocity (∼10 ps) in protic MeOH at room temperature. Efficient superluminescence properties of the peptide were realized upon femtosecond excitation in the main long-wavelength absorption band with a corresponding threshold of the pump pulse energy of ∼1.5 μJ. Quantum-chemical analysis of the electronic structure of the peptide was performed using the density functional theory/time-dependent density functional theory level of theory, affording good agreement with experimental data
ОЦЕНКА ИНВЕСТИЦИОННОЙ ПРИВЛЕКАТЕЛЬНОСТИ ОТРАСЛЕЙ РЕГИОНА В КОНТЕКСТЕ ЗЕЛЕНОГО РАЗВИТИЯ
Современные зеленые тренды в развитии экономики и внедрение ESG-принципов актуализировали вопросы инвестиционной привлекательности предприятий, отраслей и регионов. Изучение источников показало, что не во всех имеющихся методиках оценки инвестиционной привлекательности региона учитываются факторы, определяющие негативное антропогенное влияние на окружающую среду. В данной работе авторы предприняли попытку оценить инвестиционную привлекательность базовых отраслей Восточно-Казахстанской области в контексте зеленого развития и наметить пути дальнейшей интенсификации зеленых инвестиций в регионе. Предложенная методика предполагает сопоставление показателей инвестиционной привлекательности базовых отраслей региона с зеленой привлекательностью этих отраслей, характеризуемой объемом инвестиций, направляемых на охрану окружающей среды. Дополнительно было учтено возможное рассогласование темпов экономического роста отраслей региона и темпов загрязнения ими окружающей среды через включение в модель индекса декаплинга. В качестве источников информации использовались официальные данные органов статистики за 2015–2019 гг. Результаты исследования показали, что единственной отраслью с высокой зеленой привлекательностью является обрабатывающая промышленность, которая при этом имеет среднюю инвестиционную привлекательность. Учитывая необходимость индустриализации и диверсификации экономики Восточно-Казахстанского региона, авторы считают важным рекомендовать местным органам власти направить усилия на улучшение инвестиционного климата для данной отрасли. Высокую инвестиционную привлекательность имеют сельское хозяйство и строительство, а выше среднего — горнодобывающая промышленность и электроснабжение, но вместе с тем, эти отрасли остаются непривлекательными с точки зрения инвестирования природоохранных мероприятий. Повышение зеленой привлекательности обозначенных выше отраслей авторы видят в выработке действенного механизма финансирования зеленых проектов, в том числе через эмиссию зеленых облигаций предприятиями и местными исполнительными органами, а также в применении инструментов государственного регулирования, направленных на повышение эффективности зеленых инвестиций. Дальнейшие исследования могут быть связаны с обоснованием и конкретизацией регуляторных мер
Multifactorial vector of regional agriculture development
The article reveals the agriculture development potential of the Volgograd region enabling to move to the stable type of reproduction as well as its factors: the natural conditions, location, technological types of production, agrarian structure, horizontal and vertical integrations, state support. The methodological approach of the differentiation of green box subsidies is approved, the mechanism of its realization is proposed. The evidence base is substantiated by the long-term research of the soil intensification and soil quality factors influencing the soil productivity in the region.Within the boundaries of the existing natural areas, the following zones of territorial and economic development are allocated: the zones of competitive and efficient grain production; the zone of commercial sun flower production; the zones of territory and priority development. The criterion signs of their development are formulated. Alongside with the natural factor, the following factors were accepted as a criterion: the level of production adaptability and development of rural areas, the displacement of population, customary lifestyle, the arrangement of production infrastructure, resources, the structure of the agrarian economy. The evolutionary entrance of small agribusiness into the innovation-based economy has been reasoned as well as the creation on this basis of a special sector of agrarian economy—organic agriculture, which is reasonable to develop in the eld of dairy cattle-breeding and vegetable-growing.A strategic analysis of the technological types of production existing in the regional agriculture in the context of organizational units and activities is presented. These are: industrial type with innovative elements, extensive and intensive type with innovative elements, extensive and intensive type, extensive type. They provide modernization as a factor of the evolutionary formation of the innovation-based economy in the agrarian sector.Considering the global tendencies, the priorities of increasing the availability of agricultural mass producer in the market realized within a cluster, agricultural holding, cooperative are grounded
LUMINESCENT PROPERTIES OF SILVER CLUSTERS FORMED BY ION EXCHANGE METHOD IN PHOTO-THERMO-REFRACTIVE GLASS
Subject of Study.The paper deals with novel research of ion exchange duration influence on spectral-luminescent properties of silver clusters formed in photo-thermo-refractive glass. Method. Photo-thermo-refractive matrix glass based on Na2O–Al2O3–ZnO–SiO2–F (% mol.) system doped with 0,002% mol. of Sb2O3 was synthesized for further research. Silver ions were introduced with low temperature ion exchange method. The glass samples were immersed in the mixture of sodium and silver nitrates 5AgNO3/95NaNO3 (% mol.) at the temperature of 320 °C. Ion exchange duration varied from 5 minutes to 21 hours. Luminescent silver clusters were formed in surface layers of photo-thermo-refractive glass by subsequent heat treatment at the temperature of 450 °C. Main Results. Embedding of silver ions in photo-thermo-refractive glass with ion exchange method led to long-wavelength shift of the UV edge of strong absorption. Location of the UV edge of strong absorption and emission peak of silver clusters depends on ion exchange duration and shifts to the greater wavelengthswith increasing the ion exchange process time. Quantum yield of luminescence decreases significantly according to Stern-Volmer equation with the rising of ion exchange duration. Practical Relevance. Research results can be used for developing white LEDs and down-convertors of solar radiation
A Meta-analysis of Standard Versus Ultrasound-Assisted Catheter-Directed Thrombolysis in the Management of Acute Pulmonary Embolism
Background: Standard catheter-directed thrombolysis (SCDT) harnesses the therapeutic benefit of systemic thrombolytics while minimizing bleeding complications in patients presenting with pulmonary embolism (PE). Ultrasound-assisted catheter-directed thrombolysis (USAT) theoretically improves upon SCDT by disrupting fibrin and increasing the surface area exposed to thrombolytic agent. However, it is unclear if this translates into improved outcomes.
Methods: A systematic search of prior publications comparing SCDT and USAT in patients with intermediate or high-risk PE was conducted. Primary outcomes of interest were bleeding events, ICU and hospital length of stay. Secondary outcomes included changes in pulmonary artery systolic pressure (PASP), mean pulmonary artery pressure (mPAP), and right ventricle to left ventricle diameter (RV/LV) ratio. Studies that lacked comparison groups were excluded. Bias assessments were performed using the Cochrane tools for randomized and nonrandomized studies. Data was collated utilizing the Cochrane Review Manager software, and all analyses assumed random effects.
Results: Our search yielded 7 observational studies and 1 randomized control trial. The studies included a total of 543 patients who underwent either SCDT (n = 273) or USAT (n = 270) for intermediate or high-risk PE. The synthesized analysis showed no significant differences in bleeding between the groups. There were no differences in ICU or hospital lengths of stay, changes in PASP, or mPAP. Reductions in RV/LV ratio were greater with SCDT (mean difference, −0.16; 95% CI, −0.27 to −0.06; P =.003).
Conclusions: In comparison to SCDT, USAT did not result in improved clinical or hemodynamic outcomes in patients presenting with PE
Morphological differences between genetic lineages of the peregrine earthworm Aporrectodea caliginosa (Savigny, 1826)
Aporrectodea caliginosa is a universally distributed and highly abundant peregrine earthworm that is the object of many ecological and ecotoxicological studies. Molecular phylogenetic analysis suggested that A. caliginosa consists of three highly diverged genetic lineages. In this study, we investigated morphological diversity within a sample of these three lineages from Belarus. We detected a variety of forms with different degrees of pigmentation and a shift in the clitellum position. The three genetic lineages of A. caliginosa demonstrated different propensity to particular morphological variants, including size, colour, and the clitellum position, yet no character could be used to distinguish among the lineages with sufficient accuracy. Thus, our results suggest that identification of the genetic lineage should be recommended for ecological studies involving A. caliginosa to account for possible differences between them
IRE1β negatively regulates IRE1α signaling in response to endoplasmic reticulum stress
IRE1β is an ER stress sensor uniquely expressed in epithelial cells lining mucosal surfaces. Here, we show that intestinal epithelial cells expressing IRE1β have an attenuated unfolded protein response to ER stress. When modeled in HEK293 cells and with purified protein, IRE1β diminishes expression and inhibits signaling by the closely related stress sensor IRE1α. IRE1β can assemble with and inhibit IRE1α to suppress stress-induced XBP1 splicing, a key mediator of the unfolded protein response. In comparison to IRE1α, IRE1β has relatively weak XBP1 splicing activity, largely explained by a nonconserved amino acid in the kinase domain active site that impairs its phosphorylation and restricts oligomerization. This enables IRE1β to act as a dominant-negative suppressor of IRE1α and affect how barrier epithelial cells manage the response to stress at the host–environment interface
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