682 research outputs found

    Executive Summary: Young people, education, employment and ESOL

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    The report, ‘Young people, education, employment and ESOL’ reviewed 47 studies1 to examine how current ESOL provision2 meets the needs of young people aged 16-25 years who use English as an Additional Language (EAL)3, and who need time and support to develop their English language skills in order to progress in education, training and employment

    VHF scintillations, orientation of the anisotropy of F-region irregularities and direction of plasma convection in the polar cap

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    Scintillation data recorded at the polar cap station Barentsburg are shown to occasionally exhibit two or more peaks in the latitudinal profiles of the amplitude dispersion. Comparison with concurrent SuperDARN radar convection maps indicates that multiple peaks occur when Barentsburg is located within the area of strong changes in the plasma flow direction. When parameters of the ionospheric irregularities are inferred from the scintillation data, the orientation of the irregularity anisotropy in a plane perpendicular to the magnetic field is found to coincide well with the <I><b>E</b></I>×<I><B>B</B></I> flow direction, individually for each peak of the scintillation data. The differences were found to be mostly less than 20° for a data set comprised of 104 events. The conclusion is made that analysis of scintillation data allows one to infer the direction of plasma flow with a certain degree of detail

    Orientation of the cross-field anisotropy of small-scale ionospheric irregularities and direction of plasma convection

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    The relationship between the orientation of the small-scale ionospheric irregularity anisotropy in a plane perpendicular to the geomagnetic field and the direction of plasma convection in the F region is investigated. The cross-field anisotropy of irregularities is obtained by fitting theoretical expectations for the amplitude scintillations of satellite radio signals to the actual measurements. Information on plasma convection was provided by the SuperDARN HF radars. Joint satellite/radar observations in both the auroral zone and the polar cap are considered. It is shown that the irregularity cross-field anisotropy agrees quite well with the direction of plasma convection with the best agreement for events with quasi-stationary convection patterns

    GaAs(111)A and B in hydrazine sulfide solutions : extreme polarity dependence of surface adsorption processes

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    Chemical bonds formed by hydrazine-sulfide treatment of GaAs(111) were studied by synchrotron photoemission spectroscopy. At the B surface, the top arsenic atoms are replaced by nitrogen atoms, while GaAs(111)A is covered by sulfur, also bonded to underlying gallium, despite the sulfide molar concentration being 103 times smaller than that of the hydrazine. This extreme dependence on surface polarity is explained by competitive adsorption processes of HS- and OH- anions and of hydrazine molecules, on Ga- adsorption sites, which have distinct configurations on the A and B surfaces

    Spatial distribution of Oreoleuciscus potanini in evenings in the Bayan Nur lake, Мohgolia

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    Вивчено розподіл алтайського османа в одному з озер Монголії улітку. Показники ехолота GPSMAP 178 фіксували цифровим фотоапаратом. Аналіз горизонтального розподілу риб показав, що максимальна концентрація та мінімальна варіабельність густоти ехомішеней відмічена на ділянках із глибинами 6–15 м. Аналіз вертикального розподілу розрідженого скупчення риб у пелагіалі виявив дві зони концентрації риб (2–4 м і від 10 м та глибше), між якими риби відмічаються поодиноко. Щільні скупчення риб, навпаки, локалізовані в основному у середніх шарах. Изучено распределение алтайского османа в одном из озер Монголии в летнее время. Показания эхолота GPSMAP 178 фиксировали цифровым фотоаппаратом. Анализ горизонтального распределения рыб показал, что максимальная концентрация и минимальная вариабельность плотности эхомишеней отмечались на участках глубиной 6–15 м. Анализ вертикального распределения разреженного скопления рыб в пелагиали выявил две зоны концентрации рыб (2–4 м и от 10 м и глубже), между которыми рыбы отмечаются одиночно. Плотные скопления рыб, напротив, локализованы в основном в средних слоях.Distribution of the altay osman in one of the lakes of Mongolia was studied in summer. Indications of the sonar GPSMAP 178 were fixed withdigital camera. Analysis of fish horizontal distribution had shown that the maximal concentrations and minimal variability of fish density were registered in the areas with depths of 6–15 m. Analysis of vertical distribution of pelagic rarefied fish aggregationshas revealed two fish concentration zones (2–4 m and from 10 m to deeper). Between those zones the fish scores were sparse. On the contrary, dense aggregationsof fishes locate at the middle water strata in the core.

    Unoccupied Topological States on Bismuth Chalcogenides

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    The unoccupied part of the band structure of topological insulators Bi2_2Tex_{x}Se3x_{3-x} (x=0,2,3x=0,2,3) is studied by angle-resolved two-photon photoemission and density functional theory. For all surfaces linearly-dispersing surface states are found at the center of the surface Brillouin zone at energies around 1.3 eV above the Fermi level. Theoretical analysis shows that this feature appears in a spin-orbit-interaction induced and inverted local energy gap. This inversion is insensitive to variation of electronic and structural parameters in Bi2_2Se3_3 and Bi2_2Te2_2Se. In Bi2_2Te3_3 small structural variations can change the character of the local energy gap depending on which an unoccupied Dirac state does or does not exist. Circular dichroism measurements confirm the expected spin texture. From these findings we assign the observed state to an unoccupied topological surface state

    Periodization of the naturalization process of kilka (Clupeonella cultriventris) in Dneprodzerzhinsk and Kremenchug reservoirs

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    В двух водохранилищах Днепровского каскада выявлены периоды прохождения фаз натурализации массового вида рыб, что важно для изучения данного процесса у различных видов в разных регионах и для понимания роли чужеродных видов в их рыбном населении. Натурализация тюльки в рядом расположенных водоемах протекала по-разному. В акватории будущего Днепродзержинского водохранилища этот вид проник за два года до строительства плотины, а в Кременчугское он вселился через четыре года после его создания. Детализация начала фаз натурализации основана на анализе динамических фазовых портретов уловов тюльки исследовательским траломВ двух водохранилищах Днепровского каскада выявлены периоды прохождения фаз натурализации массового вида рыб, что важно для изучения данного процесса у различных видов в разных регионах и для понимания роли чужеродных видов в их рыбном населении. Натурализация тюльки в рядом расположенных водоемах протекала по-разному. В акватории будущего Днепродзержинского водохра- нилища этот вид проник за два года до строительства плотины, а в Кременчугское он вселился через четыре года после его создания. Детализация начала фаз натурализации основана на анализе динамических фазовых портретов уловов тюльки исследовательским тралом.Any species in new life conditions passes through several phases or stages of naturalization. Information about time of these phases is important for analysis of changes in invader population and understanding of the role of alien species in analysed water bodies. The aim of this work is to detect the time of occurrence of naturalization phases for the kilka in the Dniprodzerzhinsk and Kremenchug reservoirs. The analysed material includes the own data, archives of the Institute of Fisheries of the NAAS, commercial fishery statistics and literature sources. A dynamic phase portrait method was applied for detailing the time of beginning of different phases. It was established that kilka had been already present in the Dniprodzerzhinsk reservoir at the phase of II (reproduction) before its construction, and after 1967 it became the predominant pelagic species. As for the Kremenchug reservoir, kilka invaded that water body 4–5 years after its construction. It quickly passed phases I and II and by 1968 became abundant commercial species. Thus, it was found that kilka’s naturalization phases occurred differently in these nearby water bodies: in the future Dniprodzerzhinsk reservoir area, this species penetrated two years before impoundment; while in the Kremenchug reservoir it penetrated four years after the construction. Four to five years were needed for passing first three phases of kilka naturalization in the studied reservoirs. Faster progression of the phases I and II of its naturalization in the Kremenchug reservoir compared to the Dniprodzerzhinsk one indicates on better life conditions in the first water body at the moment of invasion. Currently, the studied kilka populations pass the phase IV of naturalization, which is characterized by fluctuation of population abundance

    Modeling of gene frequencies dynamics in kilka populations under the influence of natural selection factors

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    Проведено моделювання динамiки генних частот волзьких популяцiй тюльки пiд впливом факторів природного добору. Встановлено, що iнверсiя генних частот двоалельного локусу, яка спостерігається у реальній ситуацiї, може здiйснюватися тільки тоді, коли діють фактори природного добору. Проведено моделирование динамики генных частот волжских популяций тюльки под влиянием факторов природного отбора. Установлено, що инверсия генных частот двуаллельного локуса, которая наблюдается в реальной ситуации, может осуществляться только тогда, когда действуют факторы природного отбора.Modelling of gene frequencies dynamics in the Volga kilka populations under influence of the natural selection factors is carried out. It is established, that inversion of frequencies of two allelic loci, which is observed in a real situation, may occur only under the factors of natural selection. Theoretically, it can descend in an ecological time scale

    Cs-induced charge transfer on (2x4)-GaAs(001) studied by photoemission

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    Cesium adsorption on 2x4 GaAs (001) was studied by photoemission and low energy electron diffraction. The different Cs induced changes of the As 3d and Ga 3d core level spectra show that charge transfer is almost complete for Ga surface sites, but is negligible to surface As at a coverage smaller than 0.3 ML. The situation is opposite for a coverage larger than 0.3ML, at which transfer occurs to As but no longer to Ga. Charge transfer to As atoms leads to disordering and destabilization and induces surface conversion from the As-rich surface to the Ga-rich 4x2 one after annealing at a reduced temperature of 450 C
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