65 research outputs found
Classical solution of the wave equation
The classical limit of wave quantum mechanics is analyzed. It is shown that
the general requirements of continuity and finiteness to the solution
, where and
is the reduced classical action of the physical system, result in the
asymptote of the exact solution and general quantization condition for ,
which yields the exact eigenvalues of the system.Comment: 8 Pages, 10 Refs, LaTe
Semiclassical wave equation and exactness of the WKB method
The exactness of the semiclassical method for three-dimensional problems in
quantum mechanics is analyzed. The wave equation appropriate in the
quasiclassical region is derived. It is shown that application of the standard
leading-order WKB quantization condition to this equation reproduces exact
energy eigenvalues for all solvable spherically symmetric potentials.Comment: 13 page
Systematics of heavy quarkonia from Regge trajectories on and planes
In this paper we show that heavy quarckonium states, similar to light mesons,
form Regge trajectories in and planes and the slope of
these trajectories is independent on the quantum numbers of the mesons. This
fact can be useful for the prediction of the masses of heavy quarkonia and the
determination of the quantum numbers of the newly discovered states.Comment: 10 pages, 2 figures, 2 tables; some refrences are added, comparison
with QCD sum rules result is presente
About the Poisson Structure for D4 Spinning String
The model of D4 open string with non-Grassmann spinning variables is
considered. The non-linear gauge, which is invariant both Poincar\'e and scale
transformations of the space-time, is used for subsequent studies. It is shown
that the reduction of the canonical Poisson structure from the original phase
space to the surface of constraints and gauge conditions gives the degenerated
Poisson brackets. Moreover it is shown that such reduction is non-unique. The
conseption of the adjunct phase space is introduced. The consequences for
subsequent quantization are discussed. Deduced dependence of spin from the
square of mass of the string generalizes the ''Regge spectrum`` for
conventional theory.Comment: 23 page
Treatment of patients with caudal regression syn- drome: a systematic review of the literature
Objective. To analyze and summarize the data of modern literature on the issues of surgical treatment and natural course of the spine and spinal cord pathology in patients with various types of caudal regression syndrome (CRS).
Material and Methods. A systematic review of the literature on the issue of treatment of the spine and spinal cord pathology in patients with CRS was performed. Selection criteria were: articles for the period 2002â2022, original studies of populations/patients with various forms of CRS with a description of treatment methods and long-term results of treatment or observation. A total of 28 articles on the treatment of various forms of CRS with the described results of treatment of 212 patients were analyzed: 29 patients with CRS in combination with open neural tube defects and 183 patients with closed forms of CRS. Evaluation criteria included number of patients, gender, type of spinal cord pathology, type of sacral agenesis, presence of the spine and lower extremities deformities, concomitant pathology, operations performed and their complications, and results.
Results. The studied patients underwent the following surgeries on the spine and spinal cord: untethering of the spinal cord, correction and stabilization surgeries on the spine, plasty of the spinal cord herniation, plasty of the terminal meningocele, and removal of the presacarial volumetric mass. The greatest number of complications occurred after operations on the spine and sacrum. The majority of patients (67 %) with sacral agenesis by the end of the follow-up period (average 14 years) walked independently or with the help of devices, and a minority of them (33 %) could not walk. More than half of patients with CRS (67 %) had a neurogenic bladder, urinary incontinence, or
suffered from a chronic urinary tract infection. Fecal incontinence and constipation were less common (46 %).
Conclusions. Patients with CRS have a good potential for improvement/recovery of walking and pelvic organ dysfunction. This is extremely important to timely carry out multimodality treatment of patients with CRS who have neurosurgical, orthopedic, urogenital and colorectal problems in CRS, and to start early motor rehabilitation and physiotherapy
Regge description of two pseudoscalar meson production in antiproton-proton annihilation
A Regge-inspired model is used to discuss the hard exclusive two-body
hadronic reactions (pbar p ----> pi+ pi-, pi0 pi0, K+ K-, Kbar0 K0) for the
FAIR facility project at GSI with the Panda detector. The comparison between
the differential cross sections predictions and the available data is shown to
determine the values of the few parameters of the model.Comment: 9 pages, 13 figure
Hadronic Regge Trajectories: Problems and Approaches
We scrutinized hadronic Regge trajectories in a framework of two different
models --- string and potential. Our results are compared with broad spectrum
of existing theoretical quark models and all experimental data from PDG98. It
was recognized that Regge trajectories for mesons and baryons are not straight
and parallel lines in general in the current resonance region both
experimentally and theoretically, but very often have appreciable curvature,
which is flavor-dependent. For a set of baryon Regge trajectories this fact is
well described in the considered potential model. The standard string models
predict linear trajectories at high angular momenta J with some form of
nonlinearity at low J.Comment: 15 pages, 9 figures, LaTe
Development of methods of phosphorylation of citral by medial and acidic phosphites
The reactions of trimethyl phosphite with citral in the presence of acetic acid, triphenyl phosphite with citral in the presence of water and trimethyl phosphite with citral in the presence of water and triethylamine in the methanol solution were studied. On the basis of these studies, dienyl 1-hydroxyphosphonates were obtained. A convenient method of synthesizing unsaturated 1-hydroxyphosphonates was developed on the basis of reaction of dialkyl phosphites with citral in the presence of triethylamine in molar ratio 4:2:8 in alcohol solutions
Vilnius Declaration on chronic respiratory diseases : multisectoral care pathways embedding guided self-management, mHealth and air pollution in chronic respiratory diseases
Correction: Volume: 10 Issue: 1 Article Number: 49 DOI: 10.1186/s13601-020-00357-4 Published: DEC 17 2020Background: Over 1 billion people suffer from chronic respiratory diseases such as asthma, COPD, rhinitis and rhinosinusitis. They cause an enormous burden and are considered as major non-communicable diseases. Many patients are still uncontrolled and the cost of inaction is unacceptable. A meeting was held in Vilnius, Lithuania (March 23, 2018) under the patronage of the Ministry of Health and several scientific societies to propose multisectoral care pathways embedding guided self-management, mHealth and air pollution in selected chronic respiratory diseases (rhinitis, chronic rhinosinusitis, asthma and COPD). The meeting resulted in the Vilnius Declaration that was developed by the participants of the EU Summit on chronic respiratory diseases under the leadership of Euforea. Conclusion: The Vilnius Declaration represents an important step for the fight against air pollution in chronic respiratory diseases globally and has a clear strategic relevance with regard to the EU Health Strategy as it will bring added value to the existing public health knowledge.Peer reviewe
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