The leading asymptotic terms of the three-body Coulomb scattering wave function

The asymptotic wave function derived by Alt and Mukhamedzhanov [Phys. Rev. A 47, 2004 (1993)] and Mukhamedzhanov and Lieber [Phys. Rev. A 54, 3078 (1996)] has been refined in the region where the pair $(\beta,\gamma)$ remains close to each other while the third particle $\alpha$ is far away from them $(\rho_{\alpha} \to \infty$, $r_{\alpha}/\rho_{\alpha}\to 0)$. The improved wave function satisfies the Schr\"odinger equation up to the terms of order $O(1/{\rho_{\alpha}}^{3})$, provides the leading asymptotic terms of the three-body scattering wave function with Coulomb interactions and gives further insight into the continuum behavior of the three-charged-particle wave function and helps to obtain $3\to 3$ scattered wave. This opens up further ways of solving and analysing the three-body Schr\"odinger equation by numerical means

Plane problem of filtration consolidation for an elastic half-space with discontinuous initial conditions

© 2016, Pleiades Publishing, Ltd.The plane consolidation problem for an elastic half-space under an instantaneously applied vertical load is solved in the general case assuming that the Terzaghi hypothesis holds

MinMax Radon Barcodes for Medical Image Retrieval

Content-based medical image retrieval can support diagnostic decisions by clinical experts. Examining similar images may provide clues to the expert to remove uncertainties in his/her final diagnosis. Beyond conventional feature descriptors, binary features in different ways have been recently proposed to encode the image content. A recent proposal is "Radon barcodes" that employ binarized Radon projections to tag/annotate medical images with content-based binary vectors, called barcodes. In this paper, MinMax Radon barcodes are introduced which are superior to "local thresholding" scheme suggested in the literature. Using IRMA dataset with 14,410 x-ray images from 193 different classes, the advantage of using MinMax Radon barcodes over \emph{thresholded} Radon barcodes are demonstrated. The retrieval error for direct search drops by more than 15\%. As well, SURF, as a well-established non-binary approach, and BRISK, as a recent binary method are examined to compare their results with MinMax Radon barcodes when retrieving images from IRMA dataset. The results demonstrate that MinMax Radon barcodes are faster and more accurate when applied on IRMA images.Comment: To appear in proceedings of the 12th International Symposium on Visual Computing, December 12-14, 2016, Las Vegas, Nevada, US

Trojan Horse as an indirect technique in nuclear astrophysics. Resonance reactions

The Trojan Horse method is a powerful indirect technique that provides information to determine astrophysical factors for binary rearrangement processes $x + A \to b + B$ at astrophysically relevant energies by measuring the cross section for the Trojan Horse reaction $a + A \to y+ b + B$ in quasi-free kinematics. We present the theory of the Trojan Horse method for resonant binary subreactions based on the half-off-energy-shell R matrix approach which takes into account the off-energy-shell effects and initial and final state interactions.Comment: 6 pages and 1 figur

New ANCs for α+12C\alpha + {}^{12}{\rm C} synthesis obtained using extrapolation method and the SS-factor for 12C(α,γ)16O{}^{12}{\rm C}(\alpha,\gamma){}^{16}{\rm O} radiative capture

Background: The $^{12}{\rm C}(\alpha,\gamma)^{16}$O reaction, determining the survival of carbon in red giants, is of interest for nuclear reaction theory and nuclear astrophysics. Numerous attempts to obtain the astrophysical factor of the $^{12}{\rm C}(\alpha,\gamma)^{16}$O reaction, both experimental and theoretical, have been made for almost 50 years. The specifics of the $^{16}$O nuclear structure is the presence of two subthreshold bound states, (6.92 MeV, 2$^+$) and (7.12 MeV, 1$^-$), dominating the behavior of the low-energy $S$-factor. The strength of these subthreshold states is determined by their asymptotic normalization coefficients (ANCs) which need to be known with high accuracy. Recently, using the model-independent extrapolation method, Blokhintsev {\it et al.} [Eur. Phys. J. A {\bf 59}, 162 (2023)] determined the ANCs for the three subthreshold states in $^{16}$O. Purpose: In this paper, using these newly determined ANCs, we calculated the low-energy astrophysical $S$-factors for the $^{12}{\rm C}(\alpha,\gamma)^{16}$O radiative capture. Method: The $S$-factors are calculated within the framework of the $R$-matrix method using the AZURE2 code. Conclusion: Our total $S$-factor includes the resonance $E1$ and $E2$ transitions to the ground state of $^{16}$O interfering with the corresponding direct captures and cascade radiative captures to the ground state of $^{16}$O through four subthreshold states: $0_2^+,\,3^-,\, 2^+$ and $1^-$. Since our ANCs are higher than those used by deBoer {\it et al.} [Rev. Mod. Phys. {\bf 89}, 035007 (2017)], the present total $S$-factor at the most effective astrophysical energy of 300 keV is 174 keVb versus 137 keVb of that work. Accordingly, our calculated reaction rate at low temperatures ($T_{9} < 2$) is higher than the one given in the aforesaid paper

Asymptotic behavior of the Coulomb three-body scattered wave

Asymptotic forms of the scattered wave for a system of three arbitrary charged particles valid in all domains relevant to breakup are derived. The derivations are based on the relationship between the total wave function of a breakup process in a three-body system with Coulomb interactions and the wave function of the process of scattering of all three particles of the system in the continuum. The results are free from amplitude-phase ambiguity problems associated with previously known forms. A similar technique is used to obtain asymptotic forms of the three-body Coulomb Green’s function

Calculation of antihydrogen formation via antiproton scattering with excited positronium

Detailed presentation of results shown in the ealrier Phys. Rev. Lett. (114, 183201, (2015)).Shows all partial cross sections for antihydrogen formation in collisions of antiprotons with positronium in quantum states n = 1-3

A Fisher-Rao metric for paracatadioptric images of lines

In a central paracatadioptric imaging system a perspective camera takes an image of a scene reflected in a paraboloidal mirror. A 360° field of view is obtained, but the image is severely distorted. In particular, straight lines in the scene project to circles in the image. These distortions make it diffcult to detect projected lines using standard image processing algorithms. The distortions are removed using a Fisher-Rao metric which is defined on the space of projected lines in the paracatadioptric image. The space of projected lines is divided into subsets such that on each subset the Fisher-Rao metric is closely approximated by the Euclidean metric. Each subset is sampled at the vertices of a square grid and values are assigned to the sampled points using an adaptation of the trace transform. The result is a set of digital images to which standard image processing algorithms can be applied. The effectiveness of this approach to line detection is illustrated using two algorithms, both of which are based on the Sobel edge operator. The task of line detection is reduced to the task of finding isolated peaks in a Sobel image. An experimental comparison is made between these two algorithms and third algorithm taken from the literature and based on the Hough transform

Phage T4 SegB protein is a homing endonuclease required for the preferred inheritance of T4 tRNA gene region occurring in co-infection with a related phage

Homing endonucleases initiate nonreciprocal transfer of DNA segments containing their own genes and the flanking sequences by cleaving the recipient DNA. Bacteriophage T4 segB gene, which is located in a cluster of tRNA genes, encodes a protein of unknown function, homologous to homing endonucleases of the GIY-YIG family. We demonstrate that SegB protein is a site-specific endonuclease, which produces mostly 3′ 2-nt protruding ends at its DNA cleavage site. Analysis of SegB cleavage sites suggests that SegB recognizes a 27-bp sequence. It contains 11-bp conserved sequence, which corresponds to a conserved motif of tRNA TψC stem-loop, whereas the remainder of the recognition site is rather degenerate. T4-related phages T2L, RB1 and RB3 contain tRNA gene regions that are homologous to that of phage T4 but lack segB gene and several tRNA genes. In co-infections of phages T4 and T2L, segB gene is inherited with nearly 100% of efficiency. The preferred inheritance depends absolutely on the segB gene integrity and is accompanied by the loss of the T2L tRNA gene region markers. We suggest that SegB is a homing endonuclease that functions to ensure spreading of its own gene and the surrounding tRNA genes among T4-related phages

ОЦЕНКА ПОКАЗАТЕЛЕЙ СЕРДЕЧНО-СОСУДИСТОЙ СИСТЕМЫ У ЛИЦ ЮНОШЕСКОГО ВОЗРАСТА ПРИ ФИЗИЧЕСКОЙ НАГРУЗКЕ

The article presents data on the physical development of youthful persons. It was revealed that a proportional physical and the predominance of muscle strength in relation to body weight, a high strength indicator, but a low recovery coefficient, are characteristic of young men. Girls are characterized by asthenia and recovery coefficient after physical activity, corresponding to a state of fatigue. The dependence of indicators of adaptation to physical activity on body types was revealed. The overwhelming majority of boys and girls had unsatisfactory adaptation rates.В статье представлены данные физического развития лиц юношеского возраста. Выявлено, что для юношей характерно пропорциональное телосложение и преобладание мышечной силы по отношению к массе тела, высокий показатель силы, но низкий коэффициент восстановления. Для девушек характерны астенизация и коэффициент восстановления после физической нагрузки, соответствующий состоянию утомления. Выявлена зависимость показателей адаптации к физической нагрузке от типов телосложения. Подавляющее большинство юношей и девушек имели неудовлетворительные показатели адаптации