1,065 research outputs found

    Soil water retention curve of agrogray soils: influence of anisotropy and the scaling factor

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    The soil water characteristic or soil water retention curve (WRC) of medium-loamy gray forest soil horizons was studied in cylinder-shaped samples of disturbed and undisturbed structure. The sample height varied within 2-4 cm and the diameter within 4.5-10 cm. The soil monoliths were sampled in three profiles: vertically, along the slope, and across the slope in accordance with the intrasoil paleorelief formed by the fun-nel-shaped surface of the second humus horizon. The experimental WRC were approximated with the van Genuchten equatio

    The Principles and Tools of Promotion of Educational Services on the Educational Portal of the Region

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    Research objective is development of the principles and systematization of instruments of promotion of educational services on the educational portal of the region.During the research methods of a theoretical research were used: abstraction, the analysis and synthesis, ascensions from abstract to concrete.In the article, the principles of promotion of educational services on the educational portal of the region are developed and their characteristic is given. Instruments of internet marketing for promotion of educational services on the educational portal of the region are systematized and its advantages are defined. The system of indicators of assessment of quality of functioning of the educational portal based on opinion of users and experts is offered. The directions of realization of marketing strategy of promotion of educational services for achievement of her purpose — attraction new and deduction of the available clients, increase in their knowledge about activity of higher education institutions in education market are proved

    Magnetic Ordering in V-Layers of the Superconducting System of Sr2VFeAsO3

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    Results of transport, magnetic, thermal, and 75As-NMR measurements are presented for superconducting Sr2VFeAsO3 with an alternating stack of FeAs and perovskite-like block layers. Although apparent anomalies in magnetic and thermal properties have been observed at ~150 K, no anomaly in transport behaviors has been observed at around the same temperature. These results indicate that V ions in the Sr2VO3-block layers have localized magnetic moments and that V-electrons do not contribute to the Fermi surface. The electronic characteristics of Sr2VFeAsO3 are considered to be common to those of other superconducting systems with Fe-pnictogen layers.Comment: 4 pages, 4 figures, To appear in JPSJ 79 (2010) 12371

    Electronic structure and possible pseudogap behavior in iron based superconductors

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    Starting from the simplified analytic model of electronic spectrum of iron - pnictogen (chalcogen) high - temperature superconductors close to the Fermi level, we discuss the influence of antiferromagneting (AFM)scattering both for stoichiometric case and the region of possible short - range order AFM fluctuations in doped compounds. Qualitative picture of the evolution of electronic spectrum and Fermi surfaces (FS) for different dopings is presented, with the aim of comparison with existing and future ARPES experiments. Both electron and hole dopings are considered and possible pseudogap behavior connected with partial FS "destruction" is demonstrated, explaining some recent experiments.Comment: 5 pages, 4 figures, published versio

    The temporal relationship between local school closure and increased incidence of pediatric diabetic ketoacidosis

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    IMPORTANCE: The incidence of pediatric diabetic ketoacidosis (DKA) increased early in the COVID-19 pandemic, but the relative contribution of behavioral changes and viral-related pathophysiology are unknown. OBJECTIVE: To evaluate the relationship between school closure date and onset of increased DKA to help clarify the etiology of the increased incidence. DESIGN: A multi-center, quality-controlled Pediatric Intensive Care Unit (PICU) database was used to identify the number of admissions to a participating PICU with DKA on each calendar day from 60 days before local school closure to 90 days after, and compared to baseline data from the same periods in 2018-2019. Interrupted time series and multiple linear regression analyses were used to identify admission rates that differed significantly between 2020 and baseline. SETTING: Eighty-one PICUs in the United StatesParticipants: Children ages 29 days to 17 years admitted to a PICU with DKAExposures: Statewide school closureMain outcome/measure: Rate of admission to the PICU for DKA. RESULTS: There were 1936 admissions for children with DKA in 2020 and 1795 admissions/year to those same PICUs in 2018-2019. Demographics and clinical outcomes did not differ before school closure, but pandemic-era patients were less often white and had longer hospital length of stay in the post-school closure period. The difference between 2020 admissions and 2018-2019 admissions was not different than zero before school closure, and significantly higher than zero after school closure, but was significantly increased in 2020 at \u3e30 days after school closure ( CONCLUSIONS/RELEVANCE: An increase in pediatric DKA admissions began one month after school closures. Given that behavioral changes started near school closure dates and viral activity peaked weeks after, this suggests that behavioral factors may not be the primary etiology and it is possible that SARS-CoV-2 infection may have direct effects on pediatric DKA

    Electron transport, penetration depth and upper critical magnetic field of ZrB12 and MgB2

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    We report on the synthesis and measurements of the temperature dependence of resistivity, R(T), the penetration depth, l(T), and upper critical magnetic field, Hc2(T), for polycrystalline samples of dodecaboride ZrB12 and diboride MgB2. We conclude that ZrB12 as well as MgB2 behave like simple metals in the normal state with usual Bloch-Gruneisen temperature dependence of resistivity and with rather low resistive Debye temperature, TR=280 K, for ZrB12 (as compared to MgB2 with TR=900 K). The R(T) and l(T) dependencies of ZrB12 reveal a superconducting transition at Tc=6.0 K. Although a clear exponential l(T)dependence in MgB2 thin films and ceramic pellets was observed at low temperatures, this dependence was almost linear for ZrB12 below Tc/2. These features indicate s-wave pairing state in MgB2, whereas a d-wave pairing state is possible in ZrB12. A fit to the data gives a reduced energy gap 2D(0)/kTc=1.6 for MgB2 films and pellets, in good agreement with published data for 3D \pi - sheets of the Fermi surface. Contrary to conventional theories we found a linear temperature dependence of Hc2(T) for ZrB12 (Hc2(0)=0.15 T).Comment: 8 pages, 10 figures, submitted to JET

    Granulometric composition of the finite moraine ridge soils of the Upper Volga postglacial region (East European plain, Tver region)

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    At the experimental field of VNIIMZ (Tver region, village Emmauss) laid a series of 8 soil sections. The first three sections of the southern slope are confined to the transit-accumulative, transit and eluvial-transit microlandscape with a complex of gleevate and gleev soils, which changes to an eluvial-accumulative flat-topped section and similar microlandscapes of the northern slope with slightly bent and gleevate sod-podzolic light loamy soils. In samples taken every 10 cm, the particle size distribution of soils was determined by laser diffraction and sieve (>0.25 mm) methods. The differential distribution curves of soil particles are dominated by fractions of fine sand with a maximum content of diameters of 100–150 µm and silt (1–50 µm). Three granulometrically homogeneous layers are distinguished in the soil profile: the upper one with an arable horizon (0–40 cm), medium (up to 70–80 cm) and super-moraine (up to 120 cm). In the middle part of the soil profile of the northern slope, silty fractions prevail; and in the soils of the southern part of the landscape, a relatively high content of the sandy fraction is observed (the fraction of fine sand, 50–250 µm, dominates, and followed by the coarse silt fraction, 10–50 µm), which, apparently associated with the historical processes of profiles development on binary deposits, erosion, and, possibly, with modern agrotechnological processes
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