3,078 research outputs found

    Use of open electronic courses in educational activity

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    The use of open electronic courses is a relatively new tendency in education and it is not yet fully discovered by researchers. With its introduction a change in the structure of the educational system happens. Therefore, the article studies the specifics of the introduction of online courses, including requirements to them, as well as factors that slow down their active development. Due to it, the following methods of investigation were used as: analysis, synthesis, deduction, induction. As an example, Kozma Minin Nizhny Novgorod State Pedagogical University - Minin University was used. Based on the study of the "Regulations on the use of open courses in the educational activities of Minin University", it was noted, in addition to the functions of the coordination group on open education, that for the trainee at the end of the course, in the case of unsatisfactory result, the possibility of the recalculation is established. This paragraph is used not by every university. In the article we make a conclusion that open courses are a new qualitative step in the development of world education, but online courses would be much more effective as narrow-minded, adult-oriented, and deeply motivated for learning. Taken as the basis of research, Minin University showed that the university is ready for the implementation of online courses. It is one of the few universities that actively use open courses in Russia.peer-reviewe

    Measurement of the K+μ+νμγK^+\rightarrow{\mu^+}{\nu_{\mu}}{\gamma} decay form factors in the OKA experiment

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    A precise measurement of the vector and axial-vector form factors difference FVFAF_V-F_A in the K+μ+νμγK^+\rightarrow{\mu^+}{\nu_{\mu}}{\gamma} decay is presented. About 95K events of K+μ+νμγK^+\rightarrow{\mu^+}{\nu_{\mu}}{\gamma} are selected in the OKA experiment. The result is FVFA=0.134±0.021(stat)±0.027(syst)F_V-F_A=0.134\pm0.021(stat)\pm0.027(syst). Both errors are smaller than in the previous FVFAF_V-F_A measurements.Comment: 9 pages, 8 figure

    Composite bond strength improvement with thermal vibration: an experimental non-randomised study

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    Background. Secondary caries formation is a relevant issue due to poor long-term quality of composite fillings, with inherent subsequent chipping and cracking of the material. We developed a method to improve physical, mechanical and chemical properties of available composites based on thermal vibration imposed on unpolymerised composite in the formed tooth cavity directly prior to polymerisation.Objectives. Effect assessment of thermal vibration exposure on bond strength in composite restorative polymer matrix in various composite brands.Methods. The study used synchronous thermal analysis, including differential scanning calorimetry and thermogravimetry, to estimate and register thermal effects of physical and chemical processes within a temperature programme, as well as determine gaseous release, air contact and decomposition-related sample mass variation, thermal stability, reaction kinetics, polymer and inorganic filler component chemical composition, humidity and softening degree. The study covered 90 specimens 30 mg each prepared of three different composites.Results. Synchronous thermal analysis revealed a statistically significant increase in polymer matrix bond strength in the composites Estelite Sigma Quick (Tokuyama Dental), Filtek Bulk Fill Posterior Restorative (3M Espe) and DentLight (VladMiVa) after thermal vibration exposure vs. classical polymerisation of same composites (p < 0.0001). The bond strength increased by 17.00, 22.51 and 11.31%, respectively.Conclusion. The developed exposure method for altering the composite filling physical and chemical properties has been shown advantageous in a laboratory setting. Thermal vibration-pretreated composite fillings had a higher polymer matrix bond strength vs. same composites polymerised under standard conditions.The pretreatment improves composite filling quality via directly affecting the material physical and mechanical properties of hardness and bending strength

    Molecular alliance of Lymantria dispar multiple nucleopolyhedrovirus and a short unmodified antisense oligonucleotide of its anti-apoptotic IAP-3 gene: A novel approach for gypsy moth control

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    Baculovirus IAP (inhibitor-of-apoptosis) genes originated by capture of host genes. Unmodified short antisense DNA oligonucleotides (oligoDNAs) from baculovirus IAP genes can down-regulate specific gene expression profiles in both baculovirus-free and baculovirus-infected insects. In this study, gypsy moth (Lymantria dispar) larvae infected with multiple nucleopolyhedrovirus (LdMNPV), and LdMNPV-free larvae, were treated with oligoDNA antisense to the RING (really interesting new gene) domain of the LdMNPV IAP-3 gene. The results with respect to insect mortality, biomass accumulation, histological studies, RT-PCR, and analysis of DNA apoptotic fragmentation suggest that oligoRING induced increased apoptotic processes in both LdMNPV-free and LdMNPV-infected insect cells, but were more pronounced in the latter. These data open up possibilities for promising new routes of insect pest control using antisense phosphodiester DNA oligonucleotides

    Оценка термонапряженного состояния бетонного массива

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    The paper describes a technique for assessing the thermally stressed state of a concrete massif of a foundation slab made of a self-compacting concrete mixture. The proposed method consists in a preliminary calculation of temperature fields in hardening concrete. The objects of research have been self-compacting concrete mix and structural concrete in the structure mass. The choice of materials for the preparation of a concrete mixture is given and substantiated. The composition of self-compacting concrete has been used to assess the thermally stressed state. A binder with a reduced exotherm has been used in order to reduce the self-heating of concrete. Studies have been carried out to assess the specific heat release of the recommended cement depending on the initial water-cement ratio. The effect of a chemical additive on the rate and magnitude of the specific heat release of cement has been studied.  The paper presents the main theoretical provisions and an algorithm for calculating the thermal stress state of a concrete massif. The finite difference method has been used to calculate the expected temperatures and their distribution in the structure mass, and the temperature stresses in the sections of the concrete mass have been calculated to assess the thermally stressed state. The performed calculations of the temperature fields have made it possible to estimate the maximum possible temperatures and temperature differences over the sections of the concrete massif depending on the initial temperature of the concrete mixture and the average daily temperature of the outside air. Analysis of the temperature distribution has revealed the most dangerous sections of the concrete mass. An assessment of the thermal stress state of the concrete mass has been made on the basis of the results pertaining to calculation of temperature fields. The calculation of temperature stresses in the most dangerous sections of the concrete massif has been performed. It is shown that the calculated value of the temperature stress can serve as a characteristic of the thermally stressed state of the concrete mass. The formation of temperature cracks in a concrete mass is possible when the calculated value of the temperature stress exceeds the actual tensile strength of concrete. Comparison of the calculated and actual values of temperatures in the sections of the foundation slab has made it possible to conclude that the calculations of the temperature fields and, as a consequence, possible temperature deformations are correct.В статье изложена методика оценки термонапряженного состояния бетонного массива фундаментной плиты, изготовленной из самоуплотняющейся бетонной смеси. Предлагаемая методика заключается в предварительном расчете температурных полей в твердеющем бетоне. Объектами исследований являлись самоуплотняющаяся бетонная смесь и конструкционный бетон в массиве конструкции. Приведен и обоснован выбор материалов для приготовления бетонной смеси. Для оценки термонапряженного состояния использован состав самоуплотняющегося бетона. С целью снижения величины саморазогрева бетона применяли вяжущее с пониженной экзотермией. Выполнены исследования по оценке удельного тепловыделения рекомендованного цемента в зависимости от начального водоцементного отношения. Изучено влияние химической добавки на скорость и величину удельного тепловыделения цемента. Приведены основные теоретические положения и алгоритм расчета термонапряженного состояния бетонного массива. Для расчета ожидаемых температур и их распределения в массиве конструкции использовали метод конечных разностей, а для оценки термонапряженного состояния рассчитывали температурные напряжения в сечениях бетонного массива. Выполненные расчеты температурных полей позволили оценить максимально возможные температуры и температурные перепады по сечениям бетонного массива в зависимости от начальной температуры бетонной смеси и среднесуточной температуры наружного воздуха. Анализ распределения температур выявил наиболее опасные сечения бетонного массива. На основании результатов расчета температурных полей проведена оценка термонапряженного состояния бетонного массива. Выполнен расчет температурных напряжений в наиболее опасных сечениях бетонного массива. Показано, что характеристикой термонапряженного состояния бетонного массива может служить расчетная величина температурного напряжения. Образование температурных трещин в бетонном массиве возможно при превышении расчетного значения температурного напряжения над фактической прочностью бетона на растяжение. Сравнение расчетных и фактических значений температур в сечениях фундаментной плиты позволило сделать вывод о правильности выполненных расчетов температурных полей и, как следствие, о возможных температурных деформациях

    Voting 'against all' in postcommunist Russia

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    Since the early 1990s voters in Russia (and most of the other post-Soviet republics) have been offered the opportunity to vote ‘against all’ parties and candidates. Increasing numbers have done so. The evidence of two post-election surveys indicates that ‘against all’ voters are younger than other voters, more urban and more highly educated. They do not reject liberal democracy, but are critical of the contemporary practice of Russian politics and find no parties that adequately reflect their views. With the ending of the ‘against all’ facility in 2006 and other changes in the Russian electoral system under the Putin presidency, levels of turnout are likely to fall further and the protest vote will seek other outlets within or outside the parliamentary system

    Searches for the light invisible axion-like particle in K+π+π0aK^{+}\to\pi^{+}\pi^{0}a decay

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    A high statistics data sample of the K+K^{+} decays is recorded by the OKA collaboration. A missing mass analysis is performed to search for a light invisible pseudoscalar axion-like particle (ALP) aa in the decay K+π+π0aK^{+} \to \pi^{+} \pi^{0} a. No signal is observed, the upper limits for the branching ratio of the decay are calculated. The 90%90\% confidence level upper limit is changing from 2.51062.5\cdot10^{-6} to 21072\cdot10^{-7} for the ALP mass from 0 to 200 MeV/c2c^{2}, except for the region of π0\pi^{0} mass, where the upper limit is 4.41064.4\cdot10^{-6}.Comment: 6 pages, 6 figure

    Observation of K+π+π0π0γK^{+} \to \pi^{+}\pi^{0}\pi^{0}\gamma decay

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    The K+π+π0π0γK^{+} \to \pi^{+}\pi^{0}\pi^{0}\gamma decay is observed by the OKA collaboration. The branching ratio is measured to be (4.1±0.9(stat)±0.4(syst))×106(4.1 \pm 0.9(stat) \pm 0.4(syst))\times 10^{-6}. The branching ratio and γ\gamma energy spectrum are consistent with ChPT prediction.Comment: arXiv admin note: text overlap with arXiv:2310.1642

    Single electron emission in two-phase xenon with application to the detection of coherent neutrino-nucleus scattering

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    We present an experimental study of single electron emission in ZEPLIN-III, a two-phase xenon experiment built to search for dark matter WIMPs, and discuss applications enabled by the excellent signal-to-noise ratio achieved in detecting this signature. Firstly, we demonstrate a practical method for precise measurement of the free electron lifetime in liquid xenon during normal operation of these detectors. Then, using a realistic detector response model and backgrounds, we assess the feasibility of deploying such an instrument for measuring coherent neutrino-nucleus elastic scattering using the ionisation channel in the few-electron regime. We conclude that it should be possible to measure this elusive neutrino signature above an ionisation threshold of \sim3 electrons both at a stopped pion source and at a nuclear reactor. Detectable signal rates are larger in the reactor case, but the triggered measurement and harder recoil energy spectrum afforded by the accelerator source enable lower overall background and fiducialisation of the active volume

    Clinical Justification for Preliminary Thermal Exposure to Composite in the Treatment of Caries: Randomized Clinical Trial

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    Background. Polymer composites have good aesthetic characteristics and pronounced physicochemical properties, as compared to traditional restorative materials such as amalgam. However, the polymerization reaction of composite material containing bismethacrylate group commonly used in clinical practice is always accompanied by a different degree of volumetric shrinkage (2.7%~7.1%). The resulting stress can lead to adhesion failure and some other unfavorable clinical consequences, such as enamel destruction, microcracking of composite material and formation of microleakage between composite and tooth cavity wall, which can result in recurrent caries and postoperative sensitivity, thereby affecting the long-term effect of restoration. Therefore, studying the effect of preheating on composite restoration is important for its clinical application. Objective. To improve the effectiveness of treatment of patients with dental caries by improving the physicochemical properties of composite restorations.Methods. A randomized clinical trial enrolled 180 patients aged 18 to 45 years, diagnosed with dentin caries class I, according to Black (K02.1 in ICD). The study was conducted in the Dental Clinic of Kuban State Medical University, Russia. 180 composite restorations were performed in the treatment of dentin caries of molars. Patients were randomized into 2 groups): the control group — 90 patients and the main group — 90 patients. The control and main groups, in turn, were divided into three subgroups, depending on the composite used — Estelite Sigma Quick (Tokuyama Dental, Japan), Filtek Bulk Fill Posterior Restorative (3M Espe, USA) and DentLight (VladMiVa, Russia). Each subgroup consisted of 30 patients. In the control group, the classical method of filling with a composite material at “room temperature” was applied. In the main group, a composite heating conditioner “Ena Heat” (Micerium, Italy) was used to heat the composite to 55 °C before adapting the material in the formed cavity with subsequent photopolymerization. The quality of composite restorations within the clinical study was evaluated using the modified Ryge criterion immediately after treatment and after 6, 12, 18, 24 months. Statistical processing of the obtained data was carried out by means of one-factor analysis of variance using the GraphPadPrism 9 program (GraphPad Software, USA).Results. The duration of the clinical study comprised 24 months. The study revealed a statistically significant decrease in the quality of marginal fit of composite restorations (according to the Ryge score) by 20.1% (p = 0.0001) in the control group and by 5.7% (p = 0.0328) in the main group.  At the same time, no statistically significant changes in Ryge scores were reported in the subgroups of composite materials of the main group (pF = 0.9480, pE = 0.1837, pD = 0.2529). As a result of the study, an optimal time algorithm (7 seconds) for using a special furnace for preheating the composite before sealing with subsequent photopolymerization was obtained.Conclusion. The study revealed a statistically significant positive effect of the proposed algorithm for working with a heated composite on the quality of marginal fit in the long term after treatment in comparison with the classical method of working with a composite at “room temperature”
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