Constrained Dynamics of Tachyon Field in FRWL Spacetime

In this paper we continue study of tachyon scalar field described by a Dirac-Born-Infeld (DBI) type action with constraints in the cosmological context. The proposed extension of the system introducing an auxiliary field in the minisuperspace framework is discussed. A new equivalent set of constraints is constructed, satisfying the usual regularity conditions.Comment: 10 pages, to be published in the Special Issue of the Facta Universitatis Series: Physics, Chemistry and Technology devoted to the SEENET-MTP Balkan Workshop BSW2019 (3-14 June 2018, Nis, Serbia

Inflationary RSII Model with a Matter in the Bulk and Exponential Potential of Tachyon Field

In this paper we study a tachyon cosmological model based on dynamics of a 3-brane in the second Randall-Sundrum (RSII) model extended to include matter in the bulk. The presence of matter in the bulk changes warp factor which leads to modification of inflationary dynamics. The additional brane behaves effectively as a tachyon. We calculate numerically observation parameters of inflation: the scalar spectral index ($n_s$) and the tensor-to-scalar ratio ($r$) for the exponential potential of tachyon field.Comment: 9 pages, 1 figure, will be published in the Special Issue of Facta Universitatis, Series: Physics, Chemistry and Technology devoted to the SEENET-MTP Balkan Workshop BSW2018 (3-14 June 2018

Numerical Calculation of Hubble Hierarchy Parameters and Observational Parameters of Inflation

We present results obtained by a software we developed for computing observational cosmological inflation parameters: the scalar spectral index ($n_s$) and the tensor-to-scalar ratio ($r$) for a standard single field and tachyon inflation, as well as for a tachyon inflation in the second Randall-Sundrum model with an additional radion field. The calculated numerical values of observational parameters are compared with the latest results of observations obtained by the Planck Collaboration. The program is written in C/C++. The \textit{GNU Scientific Library} is used for some of the numerical computations and R language is used for data analysis and plots.Comment: 8 pages, 5 figures, based on talk presented at The 10th Jubilee Conference of the Balkan Physical Union (BPU10), 26-30 August 2018 (Sofia, Bulgaria

Tracheotomy in children

IntroductionTracheotomy is one of the most urgent procedures in medicine. It is an operative procedure that creates a surgical airway in the cervical trachea.AimTracheostomy refers to a surgical incision made into a trachea. Children are often considered “little people”, however, in medical sense, that is not completely true. The aim of our paper is to review the tracheostomy procedure in children.Materials and MethodsIn this paper, we analysed the tracheostomies in children performed in the Clinical Centre Niš (Serbia) in the five-year period from January 2015 to December 2019 inclusive. At our centre, all tracheostomies were solely performed by otolaryngologists.ResultsA total of 37 tracheotomies were performed in the studied period. There were 25 (67.6%) boys and 12 girls (32.4%). The main reason for this relatively low tracheostomy count in our study is because our practitioners are usually performing tracheostomies only in children that require urgent care. All chronic or complicated cases, if they are stable enough to transport, are referred to a higher specialised institution in Belgrade, Serbia.The youngest was a newborn, not older than 1 hour, and the oldest was 17 years old. We divided them into groups according to the age. There were 5 (13.5%) neonates, 25 (67.6%) infants, 3 (8.1%) preschoolers, 2 (5.4%) school-aged children, and 2 (5.4%) adolescents. This is in concurrence with other studies, where authors reported that the highest number of tracheostomies (around 65–70%) were performed before 1 year of age.In most cases, indication for tracheostomies were upper airway obstructions (n = 35, 94.6%). Prolonged orotracheal intubation (n = 1, 2.7%), and protective tracheostomy (n = 1, 2.7%) were the causes in the other two cases.ConclusionWhile researching the literature for this paper we found that there is little standardisation associated with tracheostomy, even though it is a procedure that is performed regularly all over the globe. There is evidence that there is a disparity in opinions not only among the practitioners in different countries, but in individual countries as well. With the increasing number of patients that require tracheostomy, we find that this topic should be addressed more carefully with the attempt to establish the best way of action for this procedure, and with that, lower the complication and mortality rates

Effect of chemical composition on the microstructure, hardness and electrical conductivity profiles of the Bi-Ge-In alloys

In this study, the microstructure, hardness, and electrical properties of selected ternary Bi-Ge-In alloys were investigated. Isothermal sections of the Bi-Ge-In system at 25, 200, and 300 ° C were extrapolated using optimized thermodynamic parameters from the literature. The used experimental techniques include optical microscopy, X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and energy dispersion spectrometry (EDS), Brinell hardness, and electrical conductivity measurements. The results of EDS phase composition analysis were compared with the calculated isothermal sections and a good overall agreement was reached. The results of the XRD were also in line with the predicted phase balance. By using ANOVA analysis and experimental results of Brinell hardness and electrical conductivity, a mathematical model was suggested for the calculation of these properties along with all composition ranges. The appropriated mathematical model was subsequently used for the prediction of hardness and electrical conductivity throughout the whole composition range

CHRONIC CONSTIPATION IN INFANTS: THINK ABOUT RECTAL DUPLICATION

Rectum is the least common site of gastrointestinal duplication. Up to now fewer than 100 cases have been reported in the literature. We present two infants with cystic rectal duplications manifested with chronic constipation as a main clinical symptom. The first patient was a 4-year-old boy who was admitted to emergency department because of chronic constipation unresponsive to fiber supplements and laxatives. Digital rectal exam revealed mass adjacent to posterior rectal wall. Abdominal ultrasound and magnetic resonance imaging confirmed oval, homogenous and hypoechogenic cystic mass (87x65x60 mm in size) behind the rectum. The size and location of the cystic mass was confirmed by magnetic resonance imaging. The second patient was an 11-month-old boy who was hospitalized due to rectal bleeding. He was suffering from chronic constipation over the last five months. Digital rectal exam revealed a mass behind the rectum. Abdominal ultrasound and computed tomography showed unilocular cyst (33X33 mm in size) in front of the urinary bladder, partly extending into retrorectal space. Both patients were operated on. Postoperative periods were uneventful in both of them. Cystic rectal duplication must be ruled out in all infants with chronic constipation unresponsive to conservative treatment. Different imaging techniques are currently used to determine the precise size and location of duplication. Surgery is the only possible therapy option