293 research outputs found
Commensurate and incommensurate magnetic order in the doped two-dimensional Hubbard model: dynamical mean-field theory analysis
We develop a dynamical mean-field theory approach for the spiral magnetic
order, changing to a local coordinate frame with preferable spin alignment
along the -axis, which can be considered with the impurity solvers treating
the spin diagonal local Green's function. We furthermore solve the
Bethe-Salpeter equations for nonuniform dynamic magnetic susceptibilities in
the local coordinate frame. We apply this approach to describe the evolution of
magnetic order with doping in the Hubbard model with , which is
appropriate for the description of the doped LaCuO high-temperature
superconductor. We find that with doping the antiferromagnetic order changes to
the incommensurate one, and then to the paramagnetic phase. The
spectral weight at the Fermi level is suppressed near half filling and
continuously increases with doping. The dispersion of holes in the
antiferromagnetic phase shows qualitative agreement with the results of the
- model consideration. In the incommensurate phase we find two branches
of hole dispersions, one of which crosses the Fermi level. The resulting Fermi
surface forms hole pockets. We also consider the dispersion of the magnetic
excitations, obtained from the non-local dynamic magnetic susceptibilities. The
transverse spin excitations are gapless, fulfilling the Goldstone theorem; in
contrast to the mean-field approach the obtained magnetic state is found to be
stable. The longitudinal excitations are characterized by a small gap, showing
the rigidity of the spin excitations. For realistic hopping and interaction
parameters we reproduce the experimentally measured spin-wave dispersion of
LaCuO.Comment: 11 pages, 9 figure
Clinical observation: congenital cystic adenomatoid malformation
The aim of the article is to describe the case of congenital cystic adenomatoid malformation. The definition of this pathology, its morphology, classification, frequency and clinical forms are considered in the work. The data of the observation of a newborn with a complicated form of the defect have been determined: the peculiarities of the neonatal adaptation, the results of examination and treatment
Prune belly syndrome: A mini-review and case report
Prune belly syndrome is a multisystem disease that is clinically manifested by a combination of hypoplasia of the abdominal muscles, bilateral cryptorchidism, and congenital anomalies of the urinary system of varying severity. The prognosis for patients with Prune belly syndrome is mainly determined by the extent of renal parenchyma dysplasia. An interdisciplinary approach involving urologists, nephrologists, surgeons, endocrinologists and other specialists allows us to improve urodynamics, to achieve stable remission of chronic obstructive pyelonephritis to perform kidney transplantation in childhood with a good result.
The article provides a mini-review of the current state of the art in etiopathogenesis, classification, diagnosis and criteria for differentiating patients according to the severity of manifestations. A clinical report of a patient with Prune belly syndrome, which was diagnosed at the age of 7 months. Who developed bilateral refluxing ureterohydronephrosis on the background of severe dysplasia of the renal parenchyma. Staged surgical correction of bilateral refluxing ureterohydronephrosis and orchiopexy at the age of 1 to 3 years was carried out. However, the loss of kidney function caused transplantation at the age of 11 years. The follow-up of this patient to the age of 15 years was presented and an evaluation of the results was discussed
On bi-hamiltonian structure of some integrable systems on so*(4)
We classify all the quadratic Poisson structures on and ,
which have the same foliation by symplectic leaves as the canonical Lie-Poisson
tensors. The separated variables for the some of the corresponding
bi-integrable systems are constructed.Comment: LaTeX with Amsfonts, 13 pages, corrected typo
The Poisson bracket compatible with the classical reflection equation algebra
We introduce a family of compatible Poisson brackets on the space of polynomial matrices, which contains the reflection equation algebra bracket.
Then we use it to derive a multi-Hamiltonian structure for a set of integrable
systems that includes the Heisenberg magnet with boundary conditions, the
generalized Toda lattices and the Kowalevski top.Comment: 13 pages, LaTeX with AmsFont
Two Types of Gastric Volvulus In Children: Case Reports And Review of The Literature
oai:oai.jctei.com:article/3Gastric volvulus (GV) is a rare pathology in children, and therefore such clinical cases cause certain difficulties not only in diagnosis, but also in treatment. However, this problem is a clinical reality in pediatric surgery and seems to be underdiagnosed because of its rareness. These patients are threatened by the development of irreversible ischemic disorders in the affected organs (not only stomach), with a high degree of probability, they may need to perform an organ-removal operation at late admission. This article presents two clinical observations of pediatric gastric volvulus of various types, with different etiopathogenesi
Systematic Error in Seed Plant Phylogenomics
Resolving the closest relatives of Gnetales has been an enigmatic problem in seed plant phylogeny. The problem is known to be difficult because of the extent of divergence between this diverse group of gymnosperms and their closest phylogenetic relatives. Here, we investigate the evolutionary properties of conifer chloroplast DNA sequences. To improve taxon sampling of Cupressophyta (non-Pinaceae conifers), we report sequences from three new chloroplast (cp) genomes of Southern Hemisphere conifers. We have applied a site pattern sorting criterion to study compositional heterogeneity, heterotachy, and the fit of conifer chloroplast genome sequences to a general time reversible + G substitution model. We show that non-time reversible properties of aligned sequence positions in the chloroplast genomes of Gnetales mislead phylogenetic reconstruction of these seed plants. When 2,250 of the most varied sites in our concatenated alignment are excluded, phylogenetic analyses favor a close evolutionary relationship between the Gnetales and Pinaceae—the Gnepine hypothesis. Our analytical protocol provides a useful approach for evaluating the robustness of phylogenomic inferences. Our findings highlight the importance of goodness of fit between substitution model and data for understanding seed plant phylogeny
BIOSOCIAL FACTORS AND PSYCHOVEGETATIVE PECULIARITIES IN FORMATION OF ADAPTATION ABNORMALITIES IN CHILDREN WITH GROWTH RETARDATION
110 children aged 7-16 with growth retardation have been under the study. Children with different clinical variants of growth retardation are characterized by individual clinical psychophysiological peculiarities. The cause-effect relation of biosocial factors, psychovegetative changes and high morbidity rate of children with growth retardation established in the research point out to their adaptation abnormalities, that require a differentiated approach to the development of rehabilitation programs
Geological structure of the northern part of the Kara Shelf near the Severnaya Zemlya archipelago according to recent studies
Until recently, the North of the Kara Shelf was completely unexplored by seismic methods. Seismic and seismo-acoustic data that have appeared in recent years have made it possible to decipher features of the regional geological structure. This study solves the urgent problem of determining the prospects for the oil and gas potential of the North Kara sedimentary basin. The relevance of the research is associated with determining the prospects of the oil and gas potential of the North Kara sedimentary basin. The aim of the study is to clarify the age of the reflecting horizons using data on the geology of the island, as well as to determine the tectonic position of the sedimentary cover and basement structures in the north of the Kara shelf. The sedimentary cover is divided into three structural levels: Cambrian-Devonian, Middle Carboniferous-Cretaceous, Miocene-Quarter. The Cambrian-Devonian complex fills the deep troughs of the North Kara shelf. The most noticeable discontinuity is the base of Carboniferous-Permian rocks, lying on the eroded surface of folded Silurian-Devonian seismic complexes. The blanket-like plate part of the cover is composed of thin Carbon-Quarter complexes. The authors came to the conclusion that the fold structures of the Taimyr-Severozemelskiy fold belt gradually degenerate towards the Kara sedimentary basin and towards the continental slope of the Eurasian basin of the Arctic Ocean. A chain of narrow uplifts within the seabed relief, which correspond to narrow anticlines is traced to the West of the Severnaya Zemlya islands. Paleozoic rocks have subhorizontal bedding further to the West, within the Kara shelf. Mesozoic folding in the North of the Kara Sea is expressed exclusively in a weak activation of movements along faults. At the neotectonic stage, the shelf near Severnaya Zemlya was raised and the Mesozoic complexes were eroded. The modern seismic activity of the North Zemlya shelf is associated with the ongoing formation of the continental margin
- …