Maximum a posteriori estimation through simulated annealing for binary asteroid orbit determination

This paper considers a new method for the binary asteroid orbit determination problem. The method is based on the Bayesian approach with a global optimisation algorithm. The orbital parameters to be determined are modelled through an a posteriori distribution made of a priori and likelihood terms. The first term constrains the parameters space and it allows the introduction of available knowledge about the orbit. The second term is based on given observations and it allows us to use and compare different observational error models. Once the a posteriori model is built, the estimator of the orbital parameters is computed using a global optimisation procedure: the simulated annealing algorithm. The maximum a posteriori (MAP) techniques are verified using simulated and real data. The obtained results validate the proposed method. The new approach guarantees independence of the initial parameters estimation and theoretical convergence towards the global optimisation solution. It is particularly useful in these situations, whenever a good initial orbit estimation is difficult to get, whenever observations are not well-sampled, and whenever the statistical behaviour of the observational errors cannot be stated Gaussian like.Comment: Accepted for publication in Monthly Notices of the Royal Astronomical Societ

Vector-field model with compensated cosmological constant and radiation-dominated FRW phase

A special model of a massless vector-field is presented, which has an extra modified-gravity-type interaction term in the action. The cosmology of the model is studied with standard noninteracting relativistic matter added. It is found that this cosmology can have an early phase where the vector-field starts to compensate a (Planck-scale) cosmological constant and a late Friedmann-Robertson-Walker (FRW) phase where the relativistic-matter energy density dominates the dynamic vacuum energy density.Comment: 12 pages, v5: published version (but with a small change in the Note Added

Measurement of the geomagnetic field in the ionosphere using radar methods

A new method for measuring the geomagnetic field in the ionosphere by the integrated use of vertical sounding radar (ionosonde) and incoherent scatter radar, its capabilities and features of the technical implementation, as well as the first results of an experimental test are considered.Розглянуто новий спосіб вимірювання геомагнітного поля в іоносфері шляхом інтегрального використання радару вертикального зондування (іонозонду) і радару некогерентного розсіяння, його можливості й особливості технічної реалізації, а також перші результати експериментального випробування

The application of plasma-electrolysis boronizing of parts

© Published under licence by IOP Publishing Ltd. The article deals with methods of increasing the working capacity of parts due to the improvement of structural condition of the surface. There were analyzed the characteristic features of the borating method and plasma-electrolysis processing, the necessity for joint use of these methods. On the basis of the review the author suggests the application of plasma-electrolysis boronizing of parts. By increasing the working capacity of parts due to the improvement of structural condition of the surface by means of borating method and plasma-electrolysis processing, it is possible to use more rational application of alloyed materials for manufacturing various parts that have high physical and mechanical, operational characteristics, which is certainly actual for modern machinery production

Cytomorphometric indicators of the gingiva epitheliocytes of patients with ischemic heart disease on the background of taking acetylsalicylic acid

The aim is to study the cytological and morphometric characteristics of gingiva epitheliocytes in patients with IHD who are constantly taking ASA drugs. To determine the dental status, 92 patients aged 40-60 years who are on outpatient treatment of IHD were examined. An in-depth scientific study was conducted and the results of cytomorphometric indicators of the gingiva epitheliocytes of patients with ischemic heart disease, constantly taking acetylsalicylic acid drugs, were presente

Possible solution to the main cosmological constant problem

A modified-gravity-type model of two hypothetical massless vector fields is presented. These vector fields are gravitationally coupled to standard matter and an effective cosmological constant. Considered in a cosmological context, the vector fields dynamically cancel an arbitrary cosmological constant, and flat Minkowski spacetime appears as the limit of attractor-type solutions of the field equations. Asymptotically, the field equations give rise to a standard Friedmann-Robertson-Walker universe and standard Newtonian gravitational dynamics of small systems.Comment: 28 pages, v5: published versio

Revisiting the 'LSND anomaly' II: critique of the data analysis

This paper, together with a preceding paper, questions the so-called 'LSND anomaly': a 3.8 sigma excess of antielectronneutrino interactions over standard backgrounds, observed by the LSND Collaboration in a beam dump experiment with 800 MeV protons. That excess has been interpreted as evidence for the antimuonneutrino to antielectronneutrino oscillation in the \Deltam2 range from 0.2 eV2 to 2 eV2. Such a \Deltam2 range is incompatible with the widely accepted model of oscillations between three light neutrino species and would require the existence of at least one light 'sterile' neutrino. In a preceding paper, it was concluded that the estimates of standard backgrounds must be significantly increased. In this paper, the LSND Collaboration's estimate of the number of antielectronneutrino interactions followed by neutron capture, and of its error, is questioned. The overall conclusion is that the significance of the 'LSND anomaly' is not larger than 2.3 sigma.Comment: 30 pages, 16 figures, 6 table

Reply to 'Corrections to the HARP-CDP Analysis of the LSND Neutrino Oscillation Backgrounds'

The alleged mistakes in recent papers that reanalyze the backgrounds to the 'LSND anomaly' do not exist. We maintain our conclusion that the significance of the 'LSND anomaly' is not 3.8 sigma but not larger than 2.3 sigma.Comment: 3 page