94 research outputs found

    Морфофункциональная характеристика ворсинчатого хориона в ранние сроки беременности при наличии урогенитальной инфекции

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    The morphological structure of the chorion villi in I trimester of pregnancy is studied at ureaplasmas and mycoplasmas infections. Established signs of the accelerated maturing of the villi, strengthened proliferation of trophoblast, increased of stromal and vascular components of chorion have been revealed.Изучено морфологическое строение ворсинчатого хориона в первом триместре беременности при уреа- и микоплазменном инфицировании. Были выявлены признаки ускоренного созревания ворсинчатого дерева, проявляющиеся усиленной пролиферацией трофобластического эпителия, приростом стромального и сосудистого компонентов ворсин

    Finite-Temperature Transport in Finite-Size Hubbard Rings in the Strong-Coupling Limit

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    We study the current, the curvature of levels, and the finite temperature charge stiffness, D(T,L), in the strongly correlated limit, U>>t, for Hubbard rings of L sites, with U the on-site Coulomb repulsion and t the hopping integral. Our study is done for finite-size systems and any band filling. Up to order t we derive our results following two independent approaches, namely, using the solution provided by the Bethe ansatz and the solution provided by an algebraic method, where the electronic operators are represented in a slave-fermion picture. We find that, in the U=\infty case, the finite-temperature charge stiffness is finite for electronic densities, n, smaller than one. These results are essencially those of spinless fermions in a lattice of size L, apart from small corrections coming from a statistical flux, due to the spin degrees of freedom. Up to order t, the Mott-Hubbard gap is \Delta_{MH}=U-4t, and we find that D(T) is finite for n<1, but is zero at half-filling. This result comes from the effective flux felt by the holon excitations, which, due to the presence of doubly occupied sites, is renormalized to \Phi^{eff}=\phi(N_h-N_d)/(N_d+N_h), and which is zero at half-filling, with N_d and N_h being the number of doubly occupied and empty lattice sites, respectively. Further, for half-filling, the current transported by any eigenstate of the system is zero and, therefore, D(T) is also zero.Comment: 15 pages and 6 figures; accepted for PR

    Enhanced Lifetime Of Excitons In Nonepitaxial Au/cds Core/shell Nanocrystals

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    The ability of metal nanoparticles to capture light through plasmon excitations offers an opportunity for enhancing the optical absorption of plasmon-coupled semiconductor materials via energy transfer. This process, however, requires that the semiconductor component is electrically insulated to prevent a backward charge flow into metal and interfacial states, which causes a premature dissociation of excitons. Here we demonstrate that such an energy exchange can be achieved on the nanoscale by using nonepitaxial Au/CdS core/shell nanocomposites. These materials are fabricated via a multistep cation exchange reaction, which decouples metal and semiconductor phases leading to fewer interfacial defects. Ultrafast transient absorption measurements confirm that the lifetime of excitons in the CdS shell (tau approximate to 300 ps) is much longer than lifetimes of excitons in conventional, reduction-grown Au/CdS heteronanostructures. As a result, the energy of metal nanoparticles can be efficiently utilized by the semiconductor component without undergoing significant nonradiative energy losses, an important property for catalytic or photovoltaic applications. The reduced rate of exciton dissociation in the CdS domain of Au/CdS nanocomposites was attributed to the nonepitaxial nature of Au/CdS interfaces associated with low defect density and a high potential barrier of the interstitial phase

    The conceptualisation of a modified formative assessment model for non-verbal students with autism and severe learning difficulties.

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    The popularity of formative assessment has increased since the publication of work by Black and Wiliam in 1998. Even though it is a useful teaching tool, in most cases it has only been possible to use it for students with high levels of cognitive and communicative ability. The aim of this article is to propose a modified, personalisable model of formative assessment for non-verbal students with autism and severe learning difficulties. Five students with autism and severe learning difficulties participated in systematic video observations over a period of eight weeks, during which student behaviour and attainment were recorded. The behaviour checklist gave an accurate representation of the students' level of engagement and predicted attainment, but differences in passive learning objectives (those requiring passive co-operation) and active ones (those requiring active contribution) were noted. The introduction of engaging resources improved engagement, but tangible rewards had a negative effect on attainment. Praise had a positive effect on engagement and attainment

    Robustness and uncertainties in global multivariate wind-wave climate projections

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    Understanding climate-driven impacts on the multivariate global wind-wave climate is paramount to effective offshore/coastal climate adaptation planning. However, the use of single-method ensembles and variations arising from different methodologies has resulted in unquantified uncertainty amongst existing global wave climate projections. Here, assessing the first coherent, community-driven, multi-method ensemble of global wave climate projections, we demonstrate widespread ocean regions with robust changes in annual mean significant wave height and mean wave period of 5–15% and shifts in mean wave direction of 5–15°, under a high-emission scenario. Approximately 50% of the world’s coastline is at risk from wave climate change, with ~40% revealing robust changes in at least two variables. Furthermore, we find that uncertainty in current projections is dominated by climate model-driven uncertainty, and that single-method modelling studies are unable to capture up to ~50% of the total associated uncertainty

    The morphological characteristic of chorion villi in early terms of pregnancy in the presence of urogenital infection

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    The morphological structure of the chorion villi in I trimester of pregnancy is studied at ureaplasmas and mycoplasmas infections. Established signs of the accelerated maturing of the villi, strengthened proliferation of trophoblast, increased of stromal and vascular components of chorion have been revealed
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