825 research outputs found
On a new compactification of moduli of vector bundles on a surface, IV: Nonreduced moduli
The construction for nonreduced projective moduli scheme of semistable
admissible pairs is performed. We establish the relation of this moduli scheme
with reduced moduli scheme built up in the previous article and prove that
nonreduced moduli scheme contains an open subscheme which is isomorphic to
moduli scheme of semistable vector bundles.Comment: 20 pages, additions and removal
Branching dendrites with resonant membrane: a “sum-over-trips” approach
Dendrites form the major components of neurons. They are complex branching structures that receive and process thousands of synaptic inputs from other neurons. It is well known that dendritic morphology plays an important role in the function of dendrites. Another important contribution to the response characteristics of a single neuron comes from the intrinsic resonant properties of dendritic membrane. In this paper we combine the effects of dendritic branching and resonant membrane dynamics by generalising the “sum-over-trips” approach (Abbott et al. in Biol Cybernetics 66, 49–60 1991). To illustrate how this formalism can shed light on the role of architecture and resonances in determining neuronal output we consider dual recording and reconstruction data from a rat CA1 hippocampal pyramidal cell. Specifically we explore the way in which an Ih current contributes to a voltage overshoot at the soma
About some economic applications of cohort analysis
Nowadays, there is the problem of evaluating the return on advertising costs for industries with a delayed conversion. Cohort analysis is a series of studies which are conducted at certain time intervals. Using cohort analysis we can better assess the effectiveness of advertising channels for industries with a delayed conversion. Cohort analysis can be used to analyze following items: efficiency in the context of "traffic sources", usefulness of changes on the web site; assessment of effectiveness of marketing campaigns; assessment of impact of seasonality on the behavior of the user; the decision-making period. The article presents an overview of tools we can use to collect data for analysis. The article also describes the method of selection and the variants of the cohorts to construct the analysis. For demonstration of the proposed method and calculation variant, there is considered the practical example of building a cohort analysis. Using these method and the example of calculating, the companies with delayed conversion can analyze the effectiveness of Internet advertising for different advertising channels. © 2018 Author(s)
The historic city as an object of cultural tourism (on the example of Yelabuga)
This paper deals with the experience of the existence of historic cities, their opportunities as centers for tourism development. At present, there are 41 historic settlements in Russia with different status. The tourist appeal of historic cities is determined primarily by their historic and cultural heritage. In recent years, such form of tourism as cultural has become more popular. Among the objects of cultural tourism is the historic and cultural heritage in its material and non-material, intangible forms. These are historic territories, including historic cities, architectural structures and complexes, archaeological excavations, art and historic museums, folk crafts, festivals, folklore, household ceremonies, traditional values, activities and the daily life style of the local population. Within the framework of cultural tourism, an individualization of demand occurs. Travelers are interested not only in getting acquainted with the well-known sights, but also in a kind of "immersion" in the historic environment, in the knowledge of the traditions and customs of the local population. Management of their historic and cultural heritage is carried out, for the most part, by reserve museums. The project activity of Yelabuga Reserve Museum is being studied as a means to increase the tourist flow and attract new partners
Democratization in a passive dendritic tree : an analytical investigation
One way to achieve amplification of distal synaptic inputs on a dendritic tree is to scale the amplitude and/or duration of the synaptic conductance with its distance from the soma. This is an example of what is often referred to as “dendritic democracy”. Although well studied experimentally, to date this phenomenon has not been thoroughly explored from a mathematical perspective. In this paper we adopt a passive model of a dendritic tree with distributed excitatory synaptic conductances and analyze a number of key measures of democracy. In particular, via moment methods we derive laws for the transport, from synapse to soma, of strength, characteristic time, and dispersion. These laws lead immediately to synaptic scalings that overcome attenuation with distance. We follow this with a Neumann approximation of Green’s representation that readily produces the synaptic scaling that democratizes the peak somatic voltage response. Results are obtained for both idealized geometries and for the more realistic geometry of a rat CA1 pyramidal cell. For each measure of democratization we produce and contrast the synaptic scaling associated with treating the synapse as either a conductance change or a current injection. We find that our respective scalings agree up to a critical distance from the soma and we reveal how this critical distance decreases with decreasing branch radius
Angular Forces Around Transition Metals in Biomolecules
Quantum-mechanical analysis based on an exact sum rule is used to extract an
semiclassical angle-dependent energy function for transition metal ions in
biomolecules. The angular dependence is simple but different from existing
classical potentials. Comparison of predicted energies with a
computer-generated database shows that the semiclassical energy function is
remarkably accurate, and that its angular dependence is optimal.Comment: Tex file plus 4 postscript figure
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STRA13 Interacts with STAT3 and Modulates Transcription of STAT3-dependent Targets
STRA13 is a pVHL-dependent bHLH transcription factor up-regulated on the mRNA level in multiple cancer cell lines and implicated recently in the regulation of immune cell homeostasis and autoimmunity. In searching for STRA13-interacting proteins with oncogenic potential by the yeast two-hybrid screening, we identified STAT3β as a STRA13-binding partner. We showed that STRA13 binds predominantly to phosphorylated (active) STAT3 α and β isoforms via its HLH and C-terminal regions. We also found that STRA13 was able to activate transcription from STAT-dependent cis-elements. Expression of endogenous STRA13 was shown to be cytokine-inducible, consistent with STRA13 involvement in STAT-dependent transcription regulation. We demonstrated that the STAT3-regulated promoter of the pro-apoptotic Fas gene was activated upon STRA13 over-expression and that co-expression of STRA13 with STAT3β or STAT3α modulated the transcriptional outcome. Forced expression of STRA13 induced apoptosis, in agreement with the STRA13 activation effect on the Fas promoter. Simultaneous expression of STRA13 and STAT3β resulted in alleviation of the STRA13 pro-apoptotic effect. Thus, for the first time, we identify STRA13 as a STAT3 partner and provide a consistent line of evidence for STRA13 involvement into regulation of apoptosis via the STAT pathways
OPTIMIZATION OF SYNTHESIS AND CHARACTERIZATION OF ZNBTC-BASED MOFS
This work was supported by the Russian Science Foundation (No. 22-73-10069)
The layer by layer selective laser synthesis of ruby
In the work, features of the layer-by-layer selective laser synthesis (SLS) of ruby from an Al2O3-Cr2O3 mixture are considered depending on the irradiation power, the laser beam traverse speed, the height and amount of the backfill of powder layers. It has been established that, under irradiation, a track consisting of polycrystalline textured ruby forms. The morphology of the surface of the track and its crystalline structure are determined by the irradiation conditions
The cyclic stability of rubber-like behaviour in stress-induced martensite aged Ni49Fe18Ga27Co6 (at.%) single crystals
In present work, the cyclic stability of the rubber-like behaviour (RLB) was investigated in Ni49Fe18Ga27Co6 (at. %) single crystals. Crystals were aged in the martensite phase at 423 K for 1 h under a compressive stress of 450 MPa, applied along the [110]B2[100]L10-direction. The RLB was induced by a preliminary chemical stabilization of the oriented L10-martensite during stress-induced martensite aging (SIM-aging) and following the reversible reorientation of martensitic variants under a compressive stress applied along the [001]B2[001]L10-direction. The high cyclic stability of the RLB was obtained in 200 loading/unloading cycles, due to the low reorientation stresses of the L10-martensite variants (no higher than 140 MPa) and the high strength properties of the L10-martensite (~1.6 GPa). The irreversible strain after 200 cycles did not exceed 0.6%. An increase in the number of cycles did not lead to the effect of destabilization of the L10-martensite
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