Time-dependent backgrounds of 2D string theory: Non-perturbative effects

We study the non-perturbative corrections (NPC) to the partition function of a compactified 2D string theory in a time-dependent background generated by a tachyon source. The sine-Liouville deformation of the theory is a particular case of such a background. We calculate the leading as well as the subleading NPC using the dual description of the string theory as matrix quantum mechanics. As in the minimal string theories, the NPC are classified by the double points of a complex curve. We calculate them by two different methods: by solving Toda equation and by evaluating the quasiclassical fermion wave functions. We show that the result can be expressed in terms of correlation functions of the bosonic field associated with the tachyon source and identify the leading and the subleading corrections as the contributions from the one-point (disk) and two-point (annulus) correlation functions.Comment: 37 pages, 2 figure

Electronic archives of documentary heritage for Balkan Wars

In this article we present information about the activities that were implemented in the project “Electronic Archive of documentary heritage of the Balkan wars”, to build a database of archival documents, photographs, new traced and researched archival materials. Information will be provided about the form and type of documents with which every institution-partner in the project will take part. The article is emphasized on the need this digital archive to include other similar institutions nationwide, and become part of the European digital library – Europeana

Prevention of blood-borne infections among nurses at Dr. Ivan Seliminski hospital, Sliven

INTRODUCTION: The occupational activities of nurses entail a daily exposure to infectious and non-infec­tious factors that can affect their health. Blood-transmitted pathogens caused by occupational exposure pose the most serious threat. Prevention strategies include vaccinations and universal precaution measures.AIM: The aim of this study is to assess vaccinations and other precautionary measures against blood-borne in­fections: HBV, HCV, HIV, and the attitude towards those among nurses at Dr. Ivan Seliminski Hospital, Sliven.MATERIALS AND METHODS: We used an individual anonymous survey among 55 nurses working in dif­ferent wards of the Hospital.RESULTS AND CONCLUSION: A large number of nurses at the hospital have had an HBV immunisation (69%). A significant proportion have also had serologic status testing for HCV and HIV (58%). Most nurses in­dicated they have had immunisation and testing as a precautionary measure

Needlestick injuries and post-exposure prophylaxis among nurses at Dr. Ivan Seliminski hospital - Sliven

INTRODUCTION: The risk of needlestick or other medical sharp instrument-induced injuries is one the most common risks among nurses. These injuries are dangerous when it comes to transmitting life-threatening blood-borne infections, including HBV, HCV and HIV. Most commonly, the risk factors are related to the oc­cupational work technique and practices, as well as the use of personal protective equipment, health and safety protocols at the work place, introducing safe medical equipment and timely post-exposure prophylaxis.AIM: The aim of this study is to examine the frequency of sharp injuries, to analyse the most common reasons for those injuries and to analyse how well nurses at Dr. Ivan Seliminski Hospital are informed about post-ex­posure measures in order to increase occupational safety.MATERIALS AND METHODS: We used an individual anonymous survey with 55 nurses working in different wards of the Hospital.RESULTS AND CONCLUSION: Needlestick injuries are most commonly inflicted after injections, in emergen­cy situations, and due to deficient health and safety protocols at the work place. Occupational exposure inci­dents are rarely reported so it is difficult to register them

2D String Theory as Normal Matrix Model

We show that the $c=1$ bosonic string theory at finite temperature has two matrix-model realizations related by a kind of duality transformation. The first realization is the standard one given by the compactified matrix quantum mechanics in the inverted oscillator potential. The second realization, which we derive here, is given by the normal matrix model. Both matrix models exhibit the Toda integrable structure and are associated with two dual cycles (a compact and a non-compact one) of a complex curve with the topology of a sphere with two punctures. The equivalence of the two matrix models holds for an arbitrary tachyon perturbation and in all orders in the string coupling constant.Comment: lanlmac, 21 page

Matrix models as conformal field theories: genus expansion

We obtain the topological expansion of the hermitian matrix model using its representation as a CFT on a hyperelliptic Riemann surface. To each branch point of the Riemann surface we associate an operator which represents a twist field dressed by the modes of the twisted boson. The partition function of the matrix model is computed as a correlation function of such dressed twist fields. The perturbative construction of the dressing operators yields a set of Feynman rules for evaluating the free energy and the loop observables at any genus.Comment: 17 pages, 4 figure

Ivan Božilov (1940.-2016.)

Nekrolog pok. bugarskom medievistu, Ivanu Božilovu

Parametric Modeling as a Technology of Rapid Prototyping in Light Industry

The paper deals with the parametric modeling method of virtual mannequins for the purposes of design automation in clothing industry. The described approach includes the steps of generation of the basic model on the ground of the initial one (obtained in 3D-scanning process), its parameterization and deformation. The complex surfaces are presented by the wireframe model. The modeling results are evaluated with the set of similarity factors. Deformed models are compared with their virtual prototypes. The results of modeling are estimated by the standard deviation factor