47 research outputs found

    First principles calculations of the Shift Current Bulk Photovoltaic Effect in Ferroelectrics

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    We calculate the bulk photovoltaic response of the ferroelectrics BaTiO3_3 and PbTiO3_3 from first principles by applying "shift current" theory to the electronic structure from density functional theory. The first principles results for BaTiO3_3 reproduce eperimental photocurrent direction and magnitude as a function of light frequency, as well as the dependence of current on light polarization, demonstrating that shift current is the dominant mechanism of the bulk photovoltaic effect in BaTiO3_3. Additionally, we analyze the relationship between response and material properties in detail. The photocurrent does not depend simply or strongly on the magnitude of material polarization, as has been previously assumed; instead, electronic states with delocalized, covalent bonding that is highly asymmetric along the current direction are required for strong shift current enhancements. The complexity of the response dependence on both external and material parameters suggests applications not only in solar energy conversion, but to photocatalysis and sensor and switch type devices as well.Comment: First submitted April 2011, submitted PRL July 201

    Improvement of 4k competences at the children's technopark «QUANTORIUM BAIKAL»

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    The article discusses the forms and methods of working with children in the classroom activities of Energykvantum on the development of 4K competencies in Technopark «Quantorium Baikal»В статье рассматриваются формы и методы работы с учащимися на занятиях направления Энерджиквантум по развитию 4Ккомпетенций у обучающихся детского технопарка «Кванториум Байкал

    Гелиогеодинамика и сейсмичность в Прибайкалье

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    The field of earthquake epicentres of Pribaikalie (Russia) is reconstructed from the data of historical and instrumental monitoring of earthquakes. The analysis shows that seismic events in the study area are distributed irregularly in space and time. The seismic process in Pribaikalie is investigated through the prism of seismic structures in the lithosphere; the irregular occurrence of seismic events in time is considered with reference to seismic weather and climate; and the causes of periodic activations of the seismic process are discovered in relation to the external effects on the Earth's physical fields from cosmic and solar processes. It is proposed to classify the seismic structures as specific geometric objects located in the lithosphere. Such objects are viewed as abstract structural elements. Some regular features are noted in the occurrence of seismic events. It is revealed that the seismic process in time shows a similarity with the course of hydrometeorological processes, which is reflected in the periodicity of elastic energy release, if only the change in the number of earthquakes (of different energy classes) in time is analysed by years. An evidently regular time pattern of seismically active periods suggests that the seismic process is influenced by some external factors. In this study, we apply the concepts of heliogeodynamics, space climate and weather to investigate such factors.Анализ эпицентрального поля землетрясений в Прибайкалье выявил пространственно-времен­ную неравномерность распределения сейсмических событий. Это позволило рассмотреть развитие сейсмического процесса через призму сейсмических структур литосферы, а неравномерность проявления событий по времени – в рамках сейсмической погоды и климата. Причины периодических активизаций сейсмического процесса связаны с внешним воздействием на физические поля Земли космических и солнечных процессов. В рамках сказанного дается классификация сейсмических структур как неких геометрических объектов, располагающихся в теле литосферы и являющихся ее абстрактными структурными элементами. Рассмотрены некоторые закономерности проявления сейсмических событий. Временной ход сейсмического процесса проявляет сходство с протеканием гидрометеорологических процессов, что находит свое отражение в периодичности реализации упругой энергии, если только рассматривать изменение во времени числа землетрясений различных энергетических классов по годам. Использованы материалы исторического и инструментального мониторинга землетрясений в Прибайкалье. Устойчивая периодичность сейсмических активизаций наводит на мысль о том, что на ход процесса влияют некие внешние факторы, рассматриваемые в рамках концепций гелиогеодинамики, космического климата и погоды

    Delineating the genotypic and phenotypic spectrum of HECW2-related neurodevelopmental disorders

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    Background Variants in HECW2 have recently been reported to cause a neurodevelopmental disorder with hypotonia, seizures and impaired language; however, only six variants have been reported and the clinical characteristics have only broadly been defined. Methods Molecular and clinical data were collected from clinical and research cohorts. Massive parallel sequencing was performed and identified individuals with a HECW2-related neurodevelopmental disorder. Results We identified 13 novel missense variants in HECW2 in 22 unpublished cases, of which 18 were confirmed to have a de novo variant. In addition, we reviewed the genotypes and phenotypes of previously reported and new cases with HECW2 variants (n=35 cases). All variants identified are missense, and the majority of likely pathogenic and pathogenic variants are located in or near the C-terminal HECT domain (88.2%). We identified several clustered variants and four recurrent variants (p.(Arg1191Gln);p.(Asn1199Lys);p.(Phe1327Ser);p.(Arg1330Trp)). Two variants, (p.(Arg1191Gln);p.(Arg1330Trp)), accounted for 22.9% and 20% of cases, respectively. Clinical characterisation suggests complete penetrance for hypotonia with or without spasticity (100%), developmental delay/intellectual disability (100%) and developmental language disorder (100%). Other common features are behavioural problems (88.9%), vision problems (83.9%), motor coordination/movement (75%) and gastrointestinal issues (70%). Seizures were present in 61.3% of individuals. Genotype-phenotype analysis shows that HECT domain variants are more frequently associated with cortical visual impairment and gastrointestinal issues. Seizures were only observed in individuals with variants in or near the HECT domain. Conclusion We provide a comprehensive review and expansion of the genotypic and phenotypic spectrum of HECW2 disorders, aiding future molecular and clinical diagnosis and management.Peer reviewe

    Delineating the molecular and phenotypic spectrum of the SETD1B-related syndrome

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    Purpose: Pathogenic variants in SETD1B have been associated with a syndromic neurodevelopmental disorder including intellectual disability, language delay, and seizures. To date, clinical features have been described for 11 patients with (likely) pathogenic SETD1B sequence variants. This study aims to further delineate the spectrum of the SETD1B-related syndrome based on characterizing an expanded patient cohort. Methods: We perform an in-depth clinical characterization of a cohort of 36 unpublished individuals with SETD1B sequence variants, describing their molecular and phenotypic spectrum. Selected variants were functionally tested using in vitro and genome-wide methylation assays. Results: Our data present evidence for a loss-of-function mechanism of SETD1B variants, resulting in a core clinical phenotype of global developmental delay, language delay including regression, intellectual disability, autism and other behavioral issues, and variable epilepsy phenotypes. Developmental delay appeared to precede seizure onset, suggesting SETD1B dysfunction impacts physiological neurodevelopment even in the absence of epileptic activity. Males are significantly overrepresented and more severely affected, and we speculate that sex-linked traits could affect susceptibility to penetrance and the clinical spectrum of SETD1B variants. Conclusion: Insights from this extensive cohort will facilitate the counseling regarding the molecular and phenotypic landscape of newly diagnosed patients with the SETD1B-related syndrome

    Technology for collecting and analyzing relational data

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    Purpose of the study. The scientific and educational organizations use traditionally e-mail with Microsoft Excel spreadsheets and Microsoft Word documents for operational data collection. The disadvantages of this approach include the lack of control of the correctness of the data input, the complexity of processing the information received due to non-relational data model, etc. There are online services that enable to organize the collection of data in a relational form. The disadvantages of these systems are: the absence of thesaurus support; a limited set of elements of data input control; the limited control the operation of the input form; most of the systems is shareware, etc. Thus, it is required the development of Internet data collection and analysis technology, which should allow to identify quickly model the data collected and automatically implement data collection in accordance with this model.Materials and methods. The article describes the technology developed and tested for operational data collection and analysis using "Faramant" system. System operation "Faramant" is based on a model document, which includes three components: description of the data structure; visualization; logic of form work. All stages of the technology are performed by the user using the browser. The main stage of the proposed technology is the definition of the data model as a set of relational tables. To create a table within the system it’s required to determine the name and a list of fields. For each field, you must specify its name and use the control to the data input and logic of his work. Controls are used to organize the correct input data depending on the data type. Based on a model system "Faramant" automatically creates a filling form, using which users can enter information. To change the form visualization, you can use the form template. The data can be viewed page by page in a table. For table rows, you can apply different filters. To summarize the information there is a mechanism of data grouping, which provides general data of the number of entries, maximum, minimum, average values for different groups of records.Results. This technology has been tested in the monitoring requirements of the services of additional professional education and the definition of the educational needs of teachers and executives of educational organizations of the Irkutsk region. The survey has involved 2,780 respondents in 36 municipalities. Creating the data model took several hours. The survey was conducted during the month.Conclusion. The proposed technology allows a short time to collect the information in relational form, and then analyze it without the need for programming with flexible assignment of the operating logic for form

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    Heliogeodynamics and seismicity in Pribaikalie

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    The field of earthquake epicentres of Pribaikalie (Russia) is reconstructed from the data of historical and instrumental monitoring of earthquakes. The analysis shows that seismic events in the study area are distributed irregularly in space and time. The seismic process in Pribaikalie is investigated through the prism of seismic structures in the lithosphere; the irregular occurrence of seismic events in time is considered with reference to seismic weather and climate; and the causes of periodic activations of the seismic process are discovered in relation to the external effects on the Earth's physical fields from cosmic and solar processes. It is proposed to classify the seismic structures as specific geometric objects located in the lithosphere. Such objects are viewed as abstract structural elements. Some regular features are noted in the occurrence of seismic events. It is revealed that the seismic process in time shows a similarity with the course of hydrometeorological processes, which is reflected in the periodicity of elastic energy release, if only the change in the number of earthquakes (of different energy classes) in time is analysed by years. An evidently regular time pattern of seismically active periods suggests that the seismic process is influenced by some external factors. In this study, we apply the concepts of heliogeodynamics, space climate and weather to investigate such factors
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