Search results for "geometry."

Splittings of Toric Ideals

2019

Let $I \subseteq R = \mathbb{K}[x_1,\ldots,x_n]$ be a toric ideal, i.e., a binomial prime ideal. We investigate when the ideal $I$ can be "split" into the sum of two smaller toric ideals. For a general toric ideal $I$, we give a sufficient condition for this splitting in terms of the integer matrix that defines $I$. When $I = I_G$ is the toric ideal of a finite simple graph $G$, we give additional splittings of $I_G$ related to subgraphs of $G$. When there exists a splitting $I = I_1+I_2$ of the toric ideal, we show that in some cases we can describe the (multi-)graded Betti numbers of $I$ in terms of the (multi-)graded Betti numbers of $I_1$ and $I_2$.

Profesors Jurijs Klokovs: biobibliogrāfiskais rādītājs

1990

Saturs: Priekšvārds. Fizikas un matemātikas zinātņu doktors profesors Jurijs Kolokovs / N. Vasiļjevs, P. Sadirbajevs. Profesora J. Kolokova publicētie darbi (1958.-1989.) J. Kolokova rediģētie un recenzētie darbi. J. Kolokova vadītās disertācijas. Literatūra par profesoru J. Kolokovu. Profesora J. Kolokova darbu alfabētiskais rādītājs. Personu rādītājs.

The internal rotational barrier of biphenyl studied with multiconfigurational second-order perturbation theory (CASPT2)

1995

A detailedab initio study of the molecular structure and rotational barriers of biphenyl has been performed. First, non-dynamical correlation effects involving the π system are taken into account at the CASSCF level. These wave functions are subsequently employed as reference functions in a multiconfigurational second-order perturbation treatment (CASPT2). The performance single-reference approaches is in addition analysed. The molecular geometries of biphenyl in twisted, coplanar, and perpendicular conformations have been optimized at the CASSCF level. A rotational angle of 44.3° is predicted for the minimum energy conformer in agreement with gas-phase electron diffraction data (44.4±1.2°)…

Active Single-Blade Installation Using Tugger Line Tension Control and Optimal Control Allocation

2020

A Robust Generic Method for Grid Detection in White Light Microscopy Malassez Blade Images in the Context of Cell Counting

2015

AbstractIn biology, cell counting is a primary measurement and it is usually performed manually using hemocytometers such as Malassez blades. This work is tedious and can be automated using image processing. An algorithm based on Fourier transform filtering and the Hough transform was developed for Malassez blade grid extraction. This facilitates cell segmentation and counting within the grid. For the present work, a set of 137 images with high variability was processed. Grids were accurately detected in 98% of these images.

Synthesis, structural investigations on organotin(IV) chlorin-e6 complexes, their effect on sea urchin embryonic development and induced apoptosis

2004

Four new organotin(IV) chlorin derivatives, [chlorin=chlorin-e(6)=21H,23H-porphine-2-propanoic acid, 18-carboxy-20-(carboxymethyl)-8-ethenyl-13-ethyl-2,3-di-hydro-3,7,12,17-tetramethyl-(2S-trans)-], with formula (R(2)Sn)(3)(chlorin)(2).2H(2)O (R=Me, n-Bu) and (R(3)Sn)(3)chlorin.2H(2)O (R=Me, Ph) have been synthesized. The solid state and solution phase structures have been investigated by FT-IR, (119)Sn Mössbauer, (1)H and (13)C NMR spectroscopy. In the solid state, (R(2)Sn)(3)(chlorin)(2).2H(2)O complexes contain six coordinated Sn(IV), in a skew trapezoidal environment by forming trans-R(2)SnO(4) polymeric units. As far as (R(3)Sn)(3)chlorin.2H(2)O complexes are concerned, Sn(IV) is five …

Plant visibility through mobile learning? Implementation and evaluation of an interactiveFlower Huntin a botanic garden

2017

Plants have an enormous importance for life on earth but are often overlooked. This phenomenon called plant blindness is reinforced as students prefer to spend their recreation time with modern med...

A double mean field equation related to a curvature prescription problem

2019

We study a double mean field-type PDE related to a prescribed curvature problem on compacts surfaces with boundary. We provide a general blow-up analysis, then a Moser-Trudinger inequality, which gives energy-minimizing solutions for some range of parameters. Finally, we provide existence of min-max solutions for a wider range of parameters, which is dense in the plane if $��$ is not simply connected.

The development of a hybrid technique employing the boundary element method for thermoelastic stress separation

2000

: This paper presents a development of a hybrid technique employing a boundary element method for determining individual stress components in two-dimensional arbitrarily shaped domains from experimental isopachics only. The procedure consists of a numerical solution of two Poisson equations representing equilibrium for two-dimensional plane-stressed solids with zero body forces. An existing technique is employed for smoothing interior thermoelastic data and enhancing boundary information. The algorithm of stress separation has been implemented with the help of commercial codes. The whole procedure has been tested through a complete post-processing example of thermoelastic stress analysis da…

Neutron diffraction studies of structural and magnetic properties of niobium doped cobaltites.

2009

Neutron powder diffraction studies of the structural and magnetic properties of the La(1-x)Sr(x)Nb(y)Co(1-y)O(3) solid solutions (x = 0.2, 0.5; y = 0, 0.075, 0.1) have been performed. Substitution of Co(2+) by Nb(5+) prevents the formation of Co(4+) and leads to stabilization of the Co(3+) ions in the high- or intermediate-spin state. This is accompanied by the significant change of the Co-O bond length as well as Co-O-Co bond angle in the CoO(6) octahedron. The obtained data are in agreement with the negative sign of the magnetic exchange interactions Co(3+)-O-Co(3+) in a relatively wide range of the Co-O-Co bond angles. Diamagnetic dilution by the niobium ions prevents long-range magnetic…