A two-component model for fitting light-curves of core-collapse supernovae

We present an improved version of a light curve model, which is able to estimate the physical properties of different types of core-collapse supernovae having double-peaked light curves, in a quick and efficient way. The model is based on a two-component configuration consisting of a dense, inner region and an extended, low-mass envelope. Using this configuration, we estimate the initial parameters of the progenitor via fitting the shape of the quasi-bolometric light curves of 10 SNe, including Type IIP and IIb events, with model light curves. In each case we compare the fitting results with available hydrodynamic calculations, and also match the derived expansion velocities with the observed ones. Furthermore, we also compare our calculations with hydrodynamic models derived by the SNEC code, and examine the uncertainties of the estimated physical parameters caused by the assumption of constant opacity and the inaccurate knowledge of the moment of explosion

TRENDS IN ROMANIAN TOURISM

Tourism is an industry of the future, having the potential to provide significant revenues, and an industry of "beauty", because it will protect, preserve and contribute to arranging the environment affected by other human activities. This is why it is very important to know the evolution of this underdeveloped field in our country. This paper is intended as a study on current trends in Romanian tourism without any claim of being an exhaustive research on the industry, describing the main indices of tourist traffic and their influence on Romanian tourism. Nowadays, we witness three main trends in Romanian tourism: sustainability, ecotourism and the increasing presence of cultural tourism. Ecotourism, as a form of tourism, has emerged from people's need to withdraw in nature, to visit and learn about the natural areas which have or have not a national or international protection status. Cultural tourism appears as a type of tourism clearly differentiated from other forms or types of tourism, particularly through motivation. It can be defined as a form of tourist mobility whose primary goal is broadening the horizon of knowledge by uncovering its architectural and artistic heritage and the areas in which it originates. Sustainability for tourism, as for other industries, has three independent aspects: economic, socio-cultural and environmental. Sustainability implies permanence, which means that sustainable tourism requires the optimal use of resources, minimizing the negative economic, socio-cultural and ecological impact, maximizing the benefits upon local communities, national economies and conservation of nature. Regarding statistical data, in what quantity is concerned, there is an increase in Romanian tourism, but in what quality is concerned there is a setback for tourism in the last years. This aspect should make public authorities take concern in improving the infrastructure and the quality of the touristical activity and in diversifying entertainment.sustenability, cultural tourism, ecotourism, trends, tourist traffic

A semi-analytical light curve model and its application to type IIP supernovae

The aim of this work is to present a semi-analytical light curve modeling code which can be used for estimating physical properties of core collapse supernovae (SNe) in a quick and efficient way. To verify our code we fit light curves of Type II SNe and compare our best parameter estimates to those from hydrodynamical calculations. For this analysis we use the quasi-bolometric light curves of five different Type IIP supernovae. In each case we get appropriate results for the initial pre-supernova parameters. We conclude that this semi-analytical light curve model is useful to get approximate physical properties of Type II SNe without using time-consuming numerical hydrodynamic simulations.Comment: accepted for publication in Astronomy \& Astrophysics; corrected Fig.2, 3,

How to solve the mass-discrepancy problem of SESNe -- I. Testing model approximations

Here, we present a systematic study of 59 stripped-envelope supernovae (SESNe) (including Type IIb, Ib, Ic, and transitional events) to map a possible reason for the so-called mass-discrepancy problem. In this scenario, we assume the tension between the estimated ejected masses from early- and late-time light curves (LC) is due to approximations generally used in analytical models. First, we examine the assumption that the R-band light curve is indeed a good approximation of the bolometric light curve. Next, we test the generally used assumption that rise-time to maximum brightness is equal to the effective diffusion time-scale that can be used to derive the ejecta mass from the early LC. In addition, we analyze the effect of gamma-ray and positron-leakage, which play an important role in forming the shape of the tails of SESNe, and also can be crucial to gaining the ejecta masses from the late-time LC data. Finally, we consider the effect of the different definitions of velocity that are needed for the ejecta mass calculations.Comment: Submitted to MNRA

Faith Commitments and Spiritual Influences as Correlates of Adolescents\u27 Involvement in Service in the Valuegenesis Study

Purpose. The first goal of this research was to examine the changes that took place over the three administrations of the Valuegenesis survey, in terms of students’ involvement in service. Secondly this study sought to determine the relationship between adolescents’ commitment to religious values and Seventh-day Adventist beliefs, and their involvement in service to others. The third goal of this research was to explore the relationship between home, church, and school variables, and the participation in acts of service of students attending Seventh-day Adventist schools. Methodology. The present research study uses quantitative research methods and is a secondary analysis. Correlations studies were done using the Valuegenesis data obtained by permission from the Hancock Research Institute. The population sample included students in Grades 6 through 12 from Seventh-day Adventist schools across North America. Results. Findings from one-way analyses of variance (ANOVA) provided empirical evidence to the changes in adolescents’ service involvement patterns over the three administrations of the Valuegenesis study (1990–1991, 2000–2001, and 2010–2011). ANOVA test results for the Horizontal Faith scale indicated a decrease in adolescents’ service involvement patterns from Valuegenesis1 to Valuegenesis2 and Valuegenesis1. Although results for the Evangelism scale were slightly higher in Valuegenesis1 than in Valuegenesis2 and Valuegenesis3, the mean scores in all three studies indicated the same frequency of students’ involvement in mission-oriented service. Likewise, though a slight increase was shown for the Altruism scale from Valuegenesis1 to Valuegenesis2, the mean scores indicated the same frequency of voluntary service involvement among adolescents participating in the studies. Canonical correlation employed to test the second hypothesis revealed significant relationship between adolescents’ commitment to religious values and their involvement in service. Results indicated that the greater adolescents’ commitment to religious values and Seventh-day Adventist beliefs the greater their involvement in service. Canonical correlational analysis, employed to test the third hypothesis, identified significant relationship between home, church, and school variables, and the service involvement of adolescents attending Seventh-day Adventist schools. Thus findings from the canonical correlation revealed that the greater the spiritual influences at home, at church, and at the Seventh-day Adventist school the greater adolescents’ involvement in service. Conclusions. Consistent with results from this study, there are some changes in the service involvement attitudes of teenagers from the first to the second and third administrations of the Valuegenesis study. Meanwhile this research indicated that adolescents’ commitment to religious values and beliefs is significantly related to their involvement in serving others. The current study also revealed a close connection between the influences of the home, the denominational school, and the church, and adolescent students’ voluntary participation in service to others

International Scientific Collaboration Links of Central Eastern European Countries Measured Through Publications

The countries of Central Eastern Europe (CEE) are lagging behind Western-Europe regarding scientific performance in the field of economics. A way to improve the quantity and quality of scientific output is to establish international scientific links with developed countries. The aim of this study is to analyze the international cooperation of Central and Eastern European countries in the field of economics. International scientific collaborations are measured through publications. The analyzed time period is 1996-2014. The used database is Scopus. Using network theory tools, it is shown that researchers from the CEE countries tend to publish more with researchers from Western Europe or the USA, rather than with researchers from the CEE region. It appears that geographical distance does not play a significant role in choosing international scientific collaboration partners. Policy decision makers should focus more on supporting and promoting research and educational mobility as these can help the CEE countries in the scientific catching-up process. This work is licensed under a&nbsp;Creative Commons Attribution-NonCommercial 4.0 International License.</p

Partnerkapcsolatok értéke a hazai autóipari ellátási láncban - fókuszban a beszállító vállalatok ---- Its title in English: Value of suppliers in the Hungarian car manufacturing industry

Műhelytanulmányunkban a versenyképesség belső szerkezetének tárgyalása alapján két problémakört jártunk körbe mind elméleti, mind - a ’A vállalati stratégia hatása az ellátási lánc menedzsment eszközeire’ című kutatás alapján - a hazai autóipari ellátási lánc példája segítségével gyakorlati szempontból. A vevői érték dimenzióinak értelmezését és jellemzését követően bemutattuk, hogy a szakirodalomban tárgyalt egyes értékdimenziók közül melyeket tudtuk beazonosítani a magyarországi autóipari beszállító vállalatok esetén. Ezt követően ismertettük a vizsgált vállalati körnek azokat a szolgáltatáscsomagjait, amelyek mentén a vállalatok alapvető képességei is megragadhatók. Végül kísérletet tettünk arra, hogy összekössük a vevői érték dimenzióit az egyes alapvető képességekkel. A vevői érték elemzése, illetve kapcsolása az alapvető képességekhez reményeink szerint segítséget nyújt mind a jelenlegi, mind a potenciális hazai beszállítók számára, hogy helyzetüket értékeljék, majd feltárják azokat a fejlődési, kitörési pontokat, amelyek hosszú távú sikerüket megalapozhatják. ------------------------ The working paper analyzes the structure and sources of firm competitiveness. Competitiveness is interpreted as an appropriate fit between two factors: (1) a set of value dimensions demanded by the customer and (2) the bundle of resources and capabilities a supplier possesses. First we describe theoretically the different value dimensions a supplier can have. After that we present those value dimensions that could have been identified in the Hungarian supplier firms of the automotive industry supply chain. Four types of suppliers are described (a) capacity based, (b) adaptive, (c) innovative and (d) system based suppliers. These typest can be distingushed based on thepotential service offerings and as a consequence of them four basic set of capabilities a suppliers have. Finally the different value dimensions a specific service offering necesitates are determined. Our analysis is based on a qualitative research program conducted at BUESPA called “The effect of strategy on supply chain management – the case of Hungarian automotive industry”