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This paper aims to identify the factors that are positively or negatively impacting students' well-being and their academic engagement. We used partial least-squares structural equation modeling (PLS-SEM) using the data collected through a questionnaire from four countries: Romania, Turkey, Slovakia, and Bulgaria. The model includes seven factors that influence the well-being of students and indirectly their academic engagement: stressors in the students' lives; professors' support; social support from family and friends; the students' perceived satisfaction in their lives; engaging in activities during their leisure time; self-exploration regarding their careers; and environmental exploration regarding their careers. The results show that all factors, except for stressors and environmental exploration regarding their careers, positively influence the students' well-being and thus their academic engagement. These findings are useful for university professors and managers in better organizing activities to increase academic performance. [ABSTRACT FROM AUTHOR]

The digital transformation of society is a reality. Technology is becoming integral to people's daily lives and children are growing up in the digital age. The education systems have to reflect and adapt to the new digital reality to effectively engage and prepare students for the future. Teachers have to possess digital competences at a high level, meaning that they are successfully able to use digital tools and technologies in their teaching practices. Digital competences include digital literacy, experience using educational software and platforms, and the ability to seamlessly integrate information and communication technologies (ICT) into the organization of educational activities. The current paper aims to study the opinion of teachers in Bulgarian schools regarding the possibilities of using digital technologies to achieve educational goals and the extent to which teachers integrate digital tools in their teaching activities. Teachers' opinions about the need for specific digital competences are important. The results of the survey show that teachers in Bulgaria actively use digital technologies in their daily teaching activities (84.8%) in order to create and provide learning content to students and to provoke their active participation, and is a convenient tool for evaluating their students' knowledge and skills and for providing effective feedback. The conducted research also identifies the necessary competences that teachers of the digital generation of learners need—skills and competences for developing authored electronic resources in various formats for students with different learning styles, as well as for working in online environments—individually and collaboratively with other teachers. [ABSTRACT FROM AUTHOR]

The principal economic sector devoted to the breeding, raising, and production of farm animals is known as the livestock industry. There are precise standards for making high-quality feed in animal husbandry. Precision livestock feeding is a crucial component, with the potential to significantly impact the profitability of livestock; it permits the provision of diets to animals that are precisely tailored to their specific daily nutritional needs. Through simulation modeling, a single model can be created for automated systems to determine daily rations for farm animals. For the purposes of this document, precision livestock feeding refers to the practice of tailoring feed to individual animals or groups of animals, taking into account their changing nutritional needs over time and individual differences in terms of nutritional requirements. The practice aims to optimize animal health and performance while reducing feed waste. This paper presents a formal model for determining the quantities of components needed to achieve a minimum cost mixture that satisfies compositional and quantitative criteria. The present research calculates the amount of hay and silage required to feed an animal per day at the most economical cost by applying an optimization approach that involves defining and solving an optimization problem. The problem is solved using a well-known software package, which is necessary for the practical application of the resulting model. Real data from livestock production in Bulgaria are used to numerically test the model. [ABSTRACT FROM AUTHOR]

This paper discusses the application of digital information management tools in the context of financial control. In Bulgaria, such research is innovative as it is the first time that digital transformation in crucial financial control institutions, which influence the formation of the revenue part of the state budget and the spending of public funds, has been studied. The study aims to answer the research question of to what extent the application of digital tools in financial control improves its effectiveness. It analyses how modern technologies improve the efficiency and accuracy of information used in financial control institutions. The authors examine the impact of digital tools, such as database management systems, business analytics platforms, and electronic document management tools, on collecting, analyzing, and managing financial and non-financial information. The study uses descriptive statistics and a correlation analysis, which significantly contributes to establishing the relationship between implemented digital tools and improvements in financial control procedures. The results show that despite the conditions created for digitalization in financial control institutions, digital tools are used to a limited extent in the information management process. The study emphasizes the need for continuous investment in digital technologies and training to maximize the benefits of their application in financial control. [ABSTRACT FROM AUTHOR]

Rainfall, with its intensity, duration, and seasonal distribution, is among the main factors causing soil erosion, which is a widespread environmental problem in Bulgaria. Rainfall erosivity shows the potential of precipitation to generate erosion processes and is an essential indicator of the climate vulnerability of a region. This paper aims to evaluate rainfall erosivity in a part of the Eastern Rhodopes Mountains, an area that is characterised by high-intensity erosion processes and high erosion risk. Local peculiarities of rainfall erosivity were revealed by the calculation of some precipitation indices based on the monthly precipitation for the period 2000–2021, such as the precipitation concentration index (PCI), Angot precipitation index, Fournier index (FI), and modified Fournier index (MFI). The analysis of the extremely wet and extremely dry months at the annual and seasonal (October–March and April–September) levels was performed to evaluate the susceptibility to erosion. The results from the study show that rainfall erosivity in the studied area varies from low to moderate in the northern part of the study area and from high to very high in the south. According to the MFI, high and very high erosivities have been observed mainly since 2012. The erosivity increases from north to south, to the area with a complex relief, where the combination of orography and atmospheric circulation make favourable conditions for the occurrence of extreme precipitation. The analyses of the calculated indices show that the precipitations in most of the studied area generally have from a low to a moderate erosivity, but this does not exclude the occurrence of cases with high and very high erosivities, which are characteristic of recent years and are related to the increase in annual precipitations and extreme precipitation months. The results of this study can contribute to the development and implementation of measures and preventive activities for the reduction and possible elimination of the negative impacts of extreme precipitation. [ABSTRACT FROM AUTHOR]

Valorization of high-volume mine tailings could be achieved by the development of new geopolymers with a low CO2 footprint. Materials rich in aluminum and silicon with appropriate solubility in an alkaline medium can be used to obtain a geopolymer. This paper presents a study of copper mine tailings from Bulgaria as precursors for geopolymers. Particle size distribution, chemical and mineralogical composition, as well as alkaline reactivity, acidity and electroconductivity of aqueous slurry are studied. The heavy metal content and their mobility are studied by leaching tests. Sequential extraction was applied to determine the geochemical phase distribution of heavy metals. The studied samples were characterized by high alkalinity, which could favor the geopolymerization process. The water-soluble sulphates were less than 4%. The Si/Al ratio in mine tailing was found to be 3. The alkaline reactivity depended more so on the time of extraction than on the concentration of NaOH solution. The main part of the heavy metals was found in the residual fraction; hence, in high alkaline medium during the geopolymerization process, they will stay fixed. Thus, the obtained geopolymers could be expected to exert low environmental impact. The presented results revealed that studied copper mine tailing is a suitable precursor for geopolymerization. [ABSTRACT FROM AUTHOR]

The main task of the National Research Program "Smart crop production", supported by the Ministry of Education and Science of Bulgaria and approved by the Council of Ministers, is the development of a regional data center to facilitate the work of farmers. The regional data center is part of the implementation of a smart crop production environment called ZEMEL which provides personal assistants supporting the work of farmers. The environment provides intelligent services for crop analysis and prevention and assists farmers in performing basic tasks related to crop production. The objective of the proposed article is to present the implementation of the architecture, infrastructure, and data architecture of a regional data center in the Plovdiv region. In order to clearly present the results of this work, which are the architectural and physical implementations of a regional data center and the storage of dynamic data and background knowledge, a methodology consisting of several steps is followed: the system infrastructure of the data center and the data architecture are discussed; one of the local pieces of infrastructure, implemented in the Institute of Plant Genetic Resources (IPGR) in the town of Sadovo in the Plovdiv region, is presented in detail, including the different types of sensors and their connection to the data center in wheat cultivation; the data repositories are discussed where dynamic data and background knowledge are stored. The paper pays special attention to background knowledge developed as ontologies for winter wheat cultivation. The results are summarized by drawing some conclusions and recommendations for the design of the local infrastructure of the center and the stored data to improve its performance. [ABSTRACT FROM AUTHOR]

In recent decades, climate change has become a critical global issue with far-reaching consequences for regional climates and ecosystems. While regional climate models provide valuable information, there is a growing need for high-resolution simulations to assess local impacts. This paper addresses this gap by presenting the first simulation of a 3 km convection-permitting (CP) scenario simulation for Bulgaria. The main aim of this study is to assess different precipitation indices and their future changes for Bulgaria under the Representative Concentration Pathway 8.5 (RCP8.5) scenario following the Coordinated Regional Climate Downscaling Experiment Flagship Pilot Study protocol. The simulations are evaluated against high-resolution observations. We downscale Coupled Model Intercomparison Project 5 Global Climate Model (CMIP5 GCM) data for historical (1995–2004) and future (2089–2098) periods using a regional climate model (RCM) at 15 km grid spacing and parametrized convection. We use these fields as initial and boundary conditions for convection-permitting kilometer-scale simulations. The 15 km grid spacing driving model is used as a reference to assess the added value of the kilometer-scale simulation. Additionally, the 3 km seasonal mean and projected 2 m temperature and the winter snow water equivalent are presented. The results show that the kilometer-scale simulation shows better performance of wet-hour intensity in all seasons, wet-hour frequency in the spring, fall, and winter, and extreme precipitation (99.9th percentile of all precipitation events, p99.9) in the winter and fall. The kilometer-scale simulation improves the projected precipitation distribution and modifies the signal of the precipitation frequency, intensity, and heavy precipitation change over some areas. A positive projected change in the wet-hour intensity is expected in all seasons (13.86% in spring, MAM, 17.48% in summer, JJA, 1.97% in fall, SON, and 17.43% in winter, DJF) and in the heavy precipitation in the spring (13.14%) and winter (31.19%) in the kilometer-scale experiment. The projected increase in mean winter precipitation is accompanied by a significant decrease in mean winter snowfall over lowlands (50−70%). The convection-permitting Regional Climate Model, version 4.7.1 (RegCM4.7.1) suggests an increase in winter snowfall over the highest parts of the country, but a significant increase in the 2 m temperatures there. The results of this study are encouraging and may be of interest to the community of climate scientists and users of climate data for making reliable estimates of the local impacts of future climate change. [ABSTRACT FROM AUTHOR]

Simple Summary: The genus Microphor contains small to very small true flies (Diptera) well known for the kleptoparasitic behavior of females, often observed as "stealing" tiny prey from spider webs. Altogether, 22 species of the genus (including 5 described in this paper) are known worldwide, and our paper loosely follows a recent study from North America. It is quite surprising that we add five new species to seven already known from West Palaearctic, which is the most studied area in the world with respect to the Diptera. Microphor baechlii sp. nov. (Switzerland, Turkey), M. chvalai sp. nov. (France), M. nevadensis sp. nov. (Spain), M. pallipes sp. nov. (Italy), and M. turcicus sp. nov. (Turkey) are described and illustrated. The neotype of M. anomalus (Meigen, 1824) is designated. Males of all known Palaearctic species of Microphor are keyed, genitalia are illustrated for new species and species previously inadequately illustrated, and main diagnostic characters are discussed. Microphorstrobli Chvála, 1986 is newly recorded from Bulgaria, M. anomalus (Meigen, 1824) is newly recorded from Turkey, and M. holosericeus (Meigen, 1804) is newly recorded from Turkey and Portugal. [ABSTRACT FROM AUTHOR]

ChatGPT has aroused the users' interest and provoked educators, researchers, and educational institutions about its role in education. Its proper integration into education can support teaching and learning activities and highlight the benefits of digital technologies. ChatGPT can be an intelligent learning assistant for learners and educators, supporting personalized and adaptive learning. At the same time, ChatGPT can be used unfairly and unethically, which causes severe concerns among educators, educational institutions, and society. Educators' attitudes regarding their application, expectations, and concerns are very important in the emergence and introduction of new technological tools in education. The current paper aims to explore the opinion of university professors at a Bulgarian university regarding the possibilities and challenges of ChatGPT in carrying out teaching activities. The findings of the conducted survey show that university professors from Trakia University in Bulgaria have an overall positive attitude regarding the implementation of ChatGPT in their teaching practice (41.4%). They perceive ChatGPT as a means to support time-consuming teaching activities (60.9%), provoke interest, activate and engage learners (59.8%), and stimulate their critical thinking and creativity (47.1%). In parallel, the university professors are concerned about possible risks of its unethical use that threaten the validity and fairness of assessment practices. The most severe problem for them is the danger that learners will completely trust ChatGPT without checking the authenticity of the generated texts (73.6%), which can negatively affect the acquisition of knowledge and skills. [ABSTRACT FROM AUTHOR]

High concentration levels of air pollutants may cause damage to plants, animals, and the health of some groups of human beings. Therefore, it is important to investigate different topics related to the high air pollution levels and to find reliable answers to the questions about the possible damages, which might take place when these levels exceed some limits. A few of the numerous questions, the answers of which are highly desirable, are listed below: (a) When are the air pollution levels dangerous? (b) What is the reason for the increased air pollution levels? (c) How can the air pollution levels be decreased? (d) Will the future climate changes result in higher and more dangerous air pollution levels? It is necessary to study carefully many issues connected with the distribution of air pollutants in a given region and with the reasons for the increases of the concentrations to high levels, which might be damaging. In order to do this, it is necessary to develop a Digital Twin of all relevant physical processes in the atmosphere and to use after that this tool in different applications. Such a tool, its name is DIGITAL AIR, has been created. Digital Twins are becoming more and more popular). Many complex problems, arising taking place in very complicated surroundings, can be handled and resolved successfully by applying Digital Twins. The preparation of such a digital tool as well as its practical implementation in the treatment of a special problem, the increase of some potentially dangerous ozone levels, will be discussed and tested in this paper. The Unified Danish Eulerian Model (UNI-DEM) is a very important part of DIGITAL AIR. This mathematical model, UNI-DEM, can be applied in many different studies related to damaging effects caused by high air pollution levels. We shall use it in this paper to get a reliable answer to a very special but extremely important question: will the future climatic changes lead to an increase in the ozone pollution levels in Bulgaria and Europe, which can potentially become dangerous for human health? [ABSTRACT FROM AUTHOR]

Earth Observation (EO) is used to monitor and assess the status of, and changes in, the natural and manmade environment via remote sensing technologies, usually involving satellites carrying imaging devices. EO applications provide important inputs to governments in planning, implementing, and monitoring the progress of the 2030 Agenda for Sustainable Development. Along with other countries, Bulgaria has committed to all 17 Sustainable Development Goals (SDGs) and reflected them in its strategic documents. EO is one of the priority technologies for the development of the Bulgarian space sector. This paper analyzes how EO data could significantly help Bulgarian authorities in achieving and monitoring the progress of the SDG targets based on three specific EO monitoring pilot projects' results (showcases) focused more on the policy management approach than scientific achievement. The first project showed the opportunities of EO data for integration of a national (local) geospatial database with the existing international networks for monitoring natural disasters and accidents. The second demonstrated the time series usage of EO data for water quality monitoring. The third project integrated remote sensing data from EO and in situ measurements with ancillaries' data to provide phenology status and crop production forecast in a common geospatial database with the aim to support the Bulgarian agriculture sector modernization. [ABSTRACT FROM AUTHOR]

In a series of papers, the initiation and development of forest fires are described in terms of the cellular automata-based Game Method for Modelling (GMM), modelling a particular area as an orthogonal grid of square cells whose values are changing with respect to predefined rules. In the present leg of this research, the simulation of the wildfire that occurred in the Kresna Gorge in Bulgaria in August 2017 is presented, rendering an account of the wind, characterized by its direction and intensity, and evaluating the impact of the fire iteratively in terms of temporal intuitionistic fuzzy sets that maintain the information about the degrees of burnt and unaffected areas. The results from the software product FireGrid, implementing the GMM-model developed by the authors, are also compared to the results from the software application FlamMap. Additionally, the paper presents for the first time the basic properties of the defined operations and operators over temporal intuitionistic fuzzy pairs. [ABSTRACT FROM AUTHOR]

The paper focuses on the association between Bulgarian adolescents' health risk behaviours (cigarette smoking, vaping, alcohol use and drunkenness) and biopsychosocial factors at individual and interpersonal levels, using data from the pre-pandemic and the pandemic periods, i.e. Health Behaviour in School-aged Children (HBSC) study (2018) and the study of adolescent health and well-being in the context of the COVID-19 pandemic (2022/2023). Logistic regression models reveal a positive association with age in both periods, decreasing gender difference in smoking, presistant effect of family structure, strengthened effect of the material status of the family and a differenciating effect of ethnicity at the end of the pandemic. Family support is positively asociated with substance (mis)use in both periods. At the end of the pandemic generalized anxiety is positively associated with substance (mis)use, loneliness has a negative association with drunkenness, and limited social interaction and vaping are in a positive relationship. The experience of COVID-19 infection in the family is associated with higher risk of smoking, while treatment in hospital for COVID-19 of the adolescent or a family member is associated with a higher risk of vaping and drunkenness. Interactions with COVID-19 experience and psychosocial variables reveal a divergence in health risk behaviours, including also engagement in substance (mis)use. Effective interventions, targeting the identified risk factors and risk groups, are needed for promotion of healthy lifestyles among adolescents. [ABSTRACT FROM AUTHOR]

Bulgaria has the lowest COVID-19 vaccination rate in the European Union and the second-highest COVID-19 mortality rate in the world. That is why we think it is important better to understand the reason for this situation and to analyse the development of the disease over time. In this paper, an extended time-dependent SEIRS model SEIRS-VB is used to investigate the long-term behaviour of the COVID-19 epidemic. This model includes vaccination and vital dynamics. To apply the SEIRS-VB model some numerical simulation tools have been developed and for this reason a family of time-discrete variants are introduced. Suitable inverse problems for the identification of parameters in discrete models are solved. A methodology is proposed for selecting a discrete model from the constructed family, which has the closest parameter values to these in the differential SEIRS-VB model. To validate the studied models, Bulgarian COVID-19 data are used. To obtain all these results for the discrete models a mathematical analysis is carried out to illustrate some biological properties of the differential model SEIRS-VB, such as the non-negativity, boundedness, existence, and uniqueness. Using the next-generation method, the basic reproduction number associated with the model in the autonomous case is defined. The local stability of the disease-free equilibrium point is studied. Finally, a sensitivity analysis of the basic reproduction number is performed. [ABSTRACT FROM AUTHOR]

The general awareness of the threats on biodiversity and water quality raised the number of studies that use phytoplankton in assessment procedures. Since most metrics require obtaining mean values, this paper presents data that may help speed up field work and find indicators for a rapid water quality assessment based on single samplings, allowing simultaneous work on many sites. The phytoplankton from 43 Bulgarian waterbodies collected during three summer campaigns (2018, 2019, 2021) at sites selected after drone observations was studied by conventional light microscopy (LM) and an HPLC analysis of marker pigments. Our results allowed us to recommend drones and the HPLC application as reliable methods in rapid water quality assessments. In total, 787 algae from seven phyla (53 alien, new for Bulgaria) were identified. Chlorophyta was the taxonomically richest group, but Cyanoprokaryota dominated the biomass in most sites. New PCR data obtained on anatoxin and microcystin producers confirmed the genetic diversity of Cuspidothrix and Microcystis and provided three new species for the country's toxic species, first identified by LM. A statistical analysis revealed significant correlations of certain algal phyla and classes with different environmental variables, and their species are considered promising for future search of bioindicators. This is especially valid for the class Eustigmatophyceae, which, as of yet, has been almost neglected in water assessment procedures and indices. [ABSTRACT FROM AUTHOR]

Business development policies cover both marketing and sales functions, as they are so intertwined in most firms. Thus, managers should comply with the factors that influence sustainable consumption behaviour. The study aims to investigate the effect of environmental knowledge (EK), materialism (MAT), environmental influences (EI), the promotion of sustainable consumption (PSC), and sustainable consumption behaviour intention (SCBI) on sustainable consumption behaviour (SCB). Although many studies have examined sustainability issues for various groups of countries, activities in this critical field in Bulgaria are severely limited, and integrated research on the subject is non-existent. This paper focuses on the importance of investigating various factors that influence sustainable consumer behaviour. A total of 489 complete and usable responses were collected from participants from all regions of Bulgaria between May 2022 and July 2022. The partial least square-structural equation modelling (PLS-SEM) and SmartPLS 4 software were employed to test the hypothesised relationships. The results indicated that EK and MAT significantly affected SCBI. Additionally, the analysis revealed the statistically significant impact of EK, MAT, EI, PSC, and SCBI on SCB. Moreover, this study demonstrated that SCBI significantly mediated the relationships between EK and SCB and between MAT and SCB. Finally, the outcomes of the moderation analysis showed that age moderated the relationship between SCBI and SCB. [ABSTRACT FROM AUTHOR]

Simple Summary: Natural enemies of cheatgrass, an invasive plant in the western USA that is associated with recent increases in destructive wildfires, were sought as part of a classical biological control program targeting that plant. A population of mites was discovered infesting cheatgrass plants in central Bulgaria and determined to be a new species using morphological, morphometric analysis (i.e., measurement of specific body parts) and DNA barcoding (i.e., comparison of DNA sequences in genes shared by all mite species). Without these modern analytical tools, this mite would probably have been considered as the same species as another mite that infests other plants. This new mite species will now be tested to determine if it is suitable for importation and release in the USA as a biological control agent of cheatgrass. A new species of eriophyoid mite, Aculodes marcellisp. nov., was discovered on cheatgrass, Anisantha tectorum (L.) Nevski (syn. Bromus tectorum L.), an annual grass that is native to Eurasia and Northern Africa. This grass was introduced to North America near the end of the 19th century and now is widespread and associated with the observed increases in the size, frequency, and intensity of wildfires in western N. America. In this paper, A. marcellisp. nov., is morphologically described and illustrated. Compared with other Aculodes spp., it differs based on morphology and the sequence of the mitochondrial cytochrome oxidase gene, subunit I (MT-CO1). Results of morphometric analysis showed clear differentiation between A. marcellisp. nov., and the most similar congener, A. altamurgiensis from Taeniatherum caput-medusae. Analysis of MT-CO1 sequence divergence revealed significant levels of genetic variation (17.7%) and supported the results from the morphometric analysis; therefore, it is determined that they are two different species. Aculodes marcellisp. nov., is a new candidate agent for classical biological control of A. tectorum. [ABSTRACT FROM AUTHOR]

The sustainable development of enterprises is based on three pillars: economic, social, and environmental. Sustainable development aims to limit climate change and its negative impact on the natural environment. The main aim of this paper is to assess the impact of selected energy economy factors (government expenditure, environmental taxes, outlays on renewable energy sources, prices of futures contracts for CO2 emissions, outlays on R&D, and the EU Emissions Trading System (ETSEU)) on the sustainable development of the energy sectors in Bulgaria, Czechia, Estonia, and Poland, from 2008 to 2022. We use the correlation coefficients, the Ordinary Least Squares (OLS), Vector Autoregressive (VAR) Models, and the simultaneous equation. The research results indicate a variation in the direction and strength of the influence of individual economic factors in the studied countries (p < 0.05). The results can support operational and strategic decisions sustaining the sustainable development of enterprises in the analyzed countries. The results indicate the need to reform selected economic factors, with an emphasis on the increased importance of environmental taxes and the reform of the EU ETS, which is a key tool for reducing greenhouse gas emissions cost-effectively. [ABSTRACT FROM AUTHOR]

The notion of "zadruga" (named by Vuk Karadjić in 1818) was introduced in the scientific research literature, as well as in the social and political discourse, of the then young Balkan countries in the 19th century to mark the multitude of historical forms under which the "complex family organization" was known among the South-Slavic people in the region. The young Bulgarian science adopted this term in ethnographic studies of the late 19th and early 20th centuries. Bulgarian scientists, lawyers, and researchers of customary law norms attempted to implement some of the features of this family model in modern Bulgarian legislation. In the period between the two world wars, the nascent cooperative movement in the agrarian sector also used the model of the "partnership" to justify its organization. This paper analyzes similar attempts to use scientific descriptions of the zadruga in the construction of various social and economic associations in Bulgaria during the interwar period. It also analyses the attempts of the new communist leaders to use the traditions of the pre-modern society in terms of communal living in zadruga through the imposition of a cooperative system, and the nationalization of the arable land in the first years under the totalitarian system following the Second World War. Part of the Bulgarian scientific community and Bulgarian ethnography has been involved in these attempts since the early 1950s. [ABSTRACT FROM AUTHOR]

Through its natural or cultivated insular population distribution, Ilex aquifolium L. is a paramount species which is exceptionally suitable for studying phenotypic variability and plasticity through the assessment of morphological, physiological, biochemical and genomic features with respect to acclimation and/or adaptation efficiency. The current study is focused on four insular populations of Ilex aquifolium from Eastern Europe (i.e., in Romania, Hungary, Serbia and Bulgaria), and presents an initial evaluation of phenotypic variability in order to conclude our research on phylogenetic relationships and phytochemical profiles, including several descriptive and quantitative morphological traits. Taken together, the data from different methods in this paper indicate that the Bulgarian and Romanian populations can be distinguished from each other and from Serbian and Hungarian populations, while the latter show a higher level of resemblance with regards to their quantitative morphological traits. It is likely that these morphological traits are determined through some quantitative trait loci implicated in stress responses generated by light, temperature, soil water, soil fertility and salinity conditions that will need to be analysed in terms of their physiological, genomic and metabolomics traits in future studies. [ABSTRACT FROM AUTHOR]

The transition from education to work in the global economy is no longer a straightforward one-time move for young people. In Bulgaria, this change started with the transition from a centrally planned economy to a market economy in the 1990s and was accompanied by the arrival of high rates of early school leaving, youth unemployment, and a growing group of disengaged youths (NEETs). The European initiatives in support of youth labour market integration are translated locally, with a narrow focus on "employability" while neglecting the many educational, training, and social needs of young people. The analysis in this paper is informed by the theoretical framework of life course research. It starts with an elaboration of the recontextualisation of EU policies such as the Youth Guarantee in the local realities of socioeconomic structures using Eurostat and national data. Second, we present 4 case studies (selected out of a total of 42 in-depth interviews) of young adults aged 18–30 in order to highlight the ways in which young people's individual agency filters and influences the institutional policies and practices regulating youth social integration. Our qualitative analysis reveals the multiplicity and diversity of youth journeys into work through the institutions and social structures and the inadequacy of the applied policy measures. [ABSTRACT FROM AUTHOR]

Global Navigation Satellite System (GNSS) is an established atmospheric monitoring technique delivering water vapour data in near-real time with a latency of 90 min for operational Numerical Weather Prediction in Europe within the GNSS water vapour service (E-GVAP). The advancement of GNSS processing made the quality of real-time GNSS tropospheric products comparable to near-real-time solutions. In addition, they can be provided with a temporal resolution of 5 min and latency of 10 min, suitable for severe weather nowcasting. This paper exploits the added value of sub-hourly real-time GNSS tropospheric products for the nowcasting of convective storms in Bulgaria. A convective Storm Demonstrator (Storm Demo) is build using real-time GNSS tropospheric products and Instability Indices to derive site-specific threshold values in support of public weather and hail suppression services. The Storm Demo targets the development of service featuring GNSS products for two regions with hail suppression operations in Bulgaria, where thunderstorms and hail events occur between May and September, with a peak in July. The Storm Demo real-time Precise Point Positioning processing is conducted with the G-Nut software with a temporal resolution of 15 min for 12 ground-based GNSS stations in Bulgaria. Real-time data evaluation is done using reprocessed products and the achieved precision is below 9 mm, which is within the nowcasting requirements of the World Meteorologic Organisation. For the period May–September 2021, the seasonal classification function for thunderstorm nowcasting is computed and evaluated. The probability of thunderstorm detection is 83%, with a false alarm ration of 38%. The added value of the high temporal resolution of the GNSS tropospheric gradients is investigated for a storm case on 24–30 August 2021. Real-time tropospheric products and classification functions are integrated and updated in real-time on a publicly accessible geoportal. [ABSTRACT FROM AUTHOR]

The present study investigates the prosodic realization of calling contours by bilingual speakers of Bulgarian and (Bulgarian) Judeo-Spanish and monolingual speakers of Bulgarian in a discourse completion task across three pragmatic contexts: (i) neutral (routine) context—calling a child from afar to come in for dinner; (ii) positive context—calling a child from afar to get a present; and (iii) negative (or urgent) context—calling a child from afar for a chastising. Through quantitative analyses of the F0 span between tonal landmarks, alignment of pitch peaks, intensity, and durational and prominence patterns, we systematically account for the phonetic characteristics of the contours and determine their tonal composition and meaning, thereby situating them within the intonation systems of Bulgarian Judeo-Spanish and Bulgarian. It is shown that both languages use the same inventory of contours: (1) L+H* !H-% (the so-called "vocative chant"), (2) L+H* H-L%, and (3) L+H* L-%. However, their distribution differs across contexts and varieties. Monolingual and bilingual speakers of Bulgarian, on the one hand, predominantly use (1) and (2) in neutral and positive contexts and clearly prefer (3) in negative contexts. In Bulgarian Judeo-Spanish, the bilinguals also more often recur to (3) in neutral and positive contexts and generally show more variation. [ABSTRACT FROM AUTHOR]

Urban water systems are still in their infancy regarding the transition toward a circular economy, despite the sporadic successful examples worldwide. This paper was aimed at analyzing the preparedness of four water utilities in Bulgaria for the implementation of circular economy principles and solutions. These utilities provide water supply and sewerage services to about 30% of the population in Bulgaria. SWOT analysis was used as a core tool. Publicly available data such as nonrevenue water, pressure management, energy demand, network digitalization, and sludge utilization were used to explore the internal factors. The external environment was considered through the legislative and socioeconomic framework, climate change, etc. Finally, the credibility of the conclusions was verified in workshops with the water utilities. The key positive outcomes were that the external factors favor the shift to circular systems, while the major weakness, i.e., the aged infrastructure, is actually a good opportunity for the implementation of modern and circular solutions. The efficient collaboration of water utilities with other actors is a precondition for the development of a sustainable market for "circular" products. [ABSTRACT FROM AUTHOR]

The present study aims to demonstrate the effects of horizontal grid resolution on the simulated pollution concentration fields over Bulgaria. The computer simulations are performed with a set of models used worldwide—the Weather Research and Forecasting Model (WRF)—the meteorological preprocessor, the Community Multiscale Air Quality Modeling System (CMAQ)—chemical transport model, Sparse Matrix Operator Kernel Emissions (SMOKE)—emission model. The large-scale (background) meteorological data used in the study were taken from the 'NCEP Global Analysis Data' with a horizontal resolution of 1° × 1°. Using the 'nesting' capabilities of the WRF and CMAQ models, a resolution of 9 km was achieved for the territory of Bulgaria by sequentially solving the task in several consecutive nested areas. Three cases are considered in this paper: Case 1: The computer simulations result from the domain with a horizontal resolution (both of the emission source description and the grid) of 27 km.; Case 2: The computer simulations result from the domain with a horizontal resolution (both of the emission source description and the grid) of 9 km.; Case 3: A hybrid case with the computer simulations performed with a grid resolution of 9 km, but with emissions such as in the 27 km × 27 km domain. The simulations were performed, for all the three cases, for the period 2007–2014 year, thus creating an ensemble large and comprehensive enough to reflect the most typical atmospheric conditions with their typical recurrence. The numerical experiments showed the significant impact of the grid resolution not only in the pollution concentration pattern but also in the demonstrated generalized characteristics. Averaged over a large territory (Bulgaria); however, the performances for cases one and two are quite similar. Bulgaria is a country with a complex topography and with several considerably large point sources. Thus, some of the conclusions made, though based on Bulgarian-specific experiments, may be of general interest. [ABSTRACT FROM AUTHOR]

In a recent publication, I introduced the theoretical framework of neosecularisation with regard to the Orthodox Church and society in Bulgaria. I argued that neosecularisation, as a complex process of decline of religion's importance and the hold of religious authority over the social system, while genealogically different from communist secularisation, explicates patterns of continuity with the communist past. Important aspects of this continuity include the persistent grassroots feminisation of the Church and the co-optation of the Church by the state. Drawing on those theoretical insights, in this paper, I seek to understand the rise of anti-gender politics in Bulgaria since 2018 in relation to the condition of neosecularisation and its impact on the Church. I argue that (neo)secularisation remains a much feared "threat" for the Church and plays a role in ecclesiastical anti-gender mobilisation. However, the Church is not a major factor in anti-gender politics in Bulgaria; the roles of far-right nationalists and certain transnationally connected evangelical actors are to be seriously considered. Furthermore, anti-genderism cannot be understood merely as a religious or cultural backlash. It needs to be discussed as a larger protest movement against liberal democracy's failure to live up to its promises and against the pathologies of neoliberal globalisation, a movement in which the Orthodox Church is only tangentially involved. [ABSTRACT FROM AUTHOR]

During a study of the distribution and status of Carabus hungaricus Fabricius, 1792 (Coleoptera: Carabidae), with pitfall traps exposed between November 2021 and April 2022, immediately south of Petrovski Krast Peak (1206 m a.s.l.) in the Chepan Planina Mt., at 1188 m a.s.l., the rare and stenotopic steppe species Carabus bessarabicus Fischer von Waldheim, 1823, was found for the first time in Bulgaria and the European Union. In October 2022, elytra of both species were also found by handpicking in the same area. The coexistence of these two specific and rare steppe species has been recorded only in few localities in Ukraine and Russia and in no EU country. This finding is also very interesting given the high conservation status of Carabus bessarabicus, the significant remoteness of its newly established locality (more than 1200 km) from its previously known range, and its strong south-westward drift. The species is used as a bioindicator for the anthropogenically uninfluenced steppe environment, which can also probably be applied in Bulgaria. The establishment of this first record for the EU also implies an increase in the conservation status of the species through its inclusion in the Union-wide conservation documents and ecological networks. [ABSTRACT FROM AUTHOR]

The efficient planning and control of timber harvesting operations is crucial to growth productivity and reducing costs, and different systems or methods are applied to obtain elevated performance. In particular, cable yarding is a highly appreciated and very efficient wood extraction method in areas that are difficult to access with ground-based extraction machines. Combined logging systems are not diffuse and not often implemented. For this reason, the use and the application of innovative methods are limited. However, some combinations have recently been observed in forest operations. This study, conducted in a deciduous stand in Bulgaria, paid attention to the combination of a tractor-mounted tower yarder (Valentini V400) with a clambunk skidder (Timberjack 1010D), aiming to examine the viability and develop the operational efficiency of the two-stage extraction system and to define the time, log volume extracted per unit by the yarder and the clambunk, and the yarding and skidding costs. The researchers carried out a time-motion study and performed a regression analysis to identify those variables that are most likely to affect the duration of work elements and productivity. For cost analysis, the COST model was used. The mean productivity of the tower yarder was 10.34 m3/PMH and 8.11 m3/SMH, while for the clambunk skidder, the productivity was 6.23 m3/PMH and 4.93 m3/SMH. The net costs for the combined logging system were calculated as 120.87 €/PMH and 14.93 €/m3. This study adds new data about the correct use of both machines, supporting their application in beech forests. [ABSTRACT FROM AUTHOR]

For more than a century, in the center of Sofia, the capital of the Republic of Bulgaria, there is and functions the church of St. Nikolai Mirlikiyski the Wonderworker, known as the Russian church. The church was built at the beginning of the 20th century with the idea of being part of the complex of the Russian imperial diplomatic body in Sofia and to serve the Russian diplomats, their families and the Orthodox Russian citizens living permanently or temporarily in the Bulgarian capital. However, after its consecration in 1914, disputes began, both regarding the ownership of the church building and the canonical jurisdiction of the church—of the Metropolitan of Sofia or the Holy Synod of the Russian Orthodox Church in Moscow. This dispute culminated in September 2023, with the expulsion from Bulgaria of several Russian and Belarusian clergies serving in the Russian church on charges of espionage in favor of the Russian Federation. The subsequent closure of the church by the Russian ambassador Mitrofanova led to internal and external political tension and ecclesiological chaos in the country. The Russian side violated the Bulgarian Law on Religions, known as the Confessions Act 2002, and directly infringed the Statute of the Bulgarian Orthodox Church. This article provides expert answers to the public law, property rights and canonical issues concerning the case of the Russian church in Sofia, based on the relevant sources of law (ecclesiastical and civil). [ABSTRACT FROM AUTHOR]

This study aims at the identification and characterization of five actinobacterial strains with presumed belonging to the species Curtobacterium flaccumfaciens isolated from tomato and pepper plants, and establishing the potential role of both plants as natural reservoirs of this phytopathogen. Species identification was performed via MALDI-ToF MS, 16S rDNA sequencing and PCR. The strains were Gram-positive with a coryneform cell shape having yellow/orange-pigmented colonies; positive for catalase and esculin, and starch and casein hydrolysis; oxidase-, urease-, indole- and nitrate-reduction-negative and were strictly aerobic. All isolates produced antimicrobial substances against various phytopathogenic bacteria. Tomato and pepper plants were artificially infected with newly isolated strains in order to establish their role as natural reservoirs of the bacteria. Morphological alterations were observed only in the tomato plants, with defoliation of the first two to four leaves at the 28th day. Then, viable coryneform bacterial isolates (n = 73) were successfully re-isolated only from the stems of the infected plants. The similarity between the re-isolates and the respective initial isolates was confirmed phenotypically and genotypically by RAPD-PCR, confirming that solanaceous vegetables can act as reservoirs of C. flaccumfaciens. This is the first report of C. flaccumfaciens in Bulgaria. [ABSTRACT FROM AUTHOR]

Assisting women in attaining their reproductive goals is crucial for improving the well-being of families and children. As the first point of contact for healthcare, general practitioners (GPs) are ideal for family planning (FP) and preconception care (PCC). However, primary care interventions' efficacy is unclear. The aim of this study was to examine GPs' knowledge, attitudes, and perspectives on FP and PCC service management. Most GPs were aware of FP and PCC services and held a firm conviction that they should be primarily accountable together with obstetrician–gynaecologists. However, it is worth noting that less than 50% of respondents reported receiving thorough and comprehensive knowledge of their respective specialities. Those with general medicine qualifications demonstrated a high level of commitment to providing such services. The women's GPs and those with training in general medicine prescribed birth control pills and emergency contraception three times more frequently than the other doctors who suggested condoms or traditional methods or referred patients to another specialist (p < 0.05). In conclusion, PCC is of the utmost importance, and its effective implementation demands the collaboration of policymakers, healthcare providers, and individuals. GPs are essential in managing FP and PCC. They must incorporate more in-depth PCC into their clinical practice. [ABSTRACT FROM AUTHOR]

A number of Phytophthora species have been identified as destructive plant pathogens and invasive species. They have the potential to affect a wide range of host plants and cause diseases in agricultural and forest ecosystems. Two Phytophthora species from rhizosphere soil samples collected from declining Alnus glutinosa in Bulgaria were isolated in the autumn of 2022. They were identified as Phytophthora polonica and Phytophthora hydropathica according to the DNA sequence analysis of the ITS region, as well as their morphological and physiological characteristics. The pathogenicity of both species to common and gray alder was evaluated by the inoculation of detached leaves and cuttings. Experimental data proved that P. polonica and P. hydropathica are able to cause leaf necrosis not only on A. glutinosa from which they were derived, but also on A. incana. No significant deference in the aggressiveness of the studied isolates from both Phytophthora species against the two tested plants was observed. Therefore, P. polonica and P. hydropathica were determined as potential threats for alder ecosystems in the country. This is the first report for the isolation of P. polonica in Bulgaria and represents the most southeastern point of the species distribution in Europe. [ABSTRACT FROM AUTHOR]

The objective of the present study is to analyze the link between the degree of professional burnout among general practitioners in Bulgaria during a pandemic and their satisfaction with the balance between their personal lives and professional lives. A cross-sectional study was conducted during the fourth wave of the COVID-19 pandemic from December 2021 to January 2022 among 377 general practitioners. We identified the presence and level of burnout syndrome among GPs using V. Boyko's method for diagnostics of the severity of symptoms and the phases of formation and completion of the 'occupational burnout' process. Descriptive statistics and parametric and non-parametric tests were used for the analysis. For the significance level of the null hypothesis, we assumed that p < 0.05 at a 95% confidence interval. A total of 96.3% of the GPs had a high level of burnout during the COVID-19 pandemic. They worked more than 8 h a day (74.8%) and more than 5 days a week (69.0%). A total of 86.3% of them were not satisfied with the spare time they had and stated that they could not balance their work and personal lives (67.1%) since the pandemic was announced. A link was found between the level of professional burnout and long working hours (p = 0.022), dissatisfaction with free time (p = 0.028), and the inability to balance work and personal life (p = 0.000), as well as concerns related to safety during the pandemic (p = 0.048). Unrealistically high levels of burnout during the COVID-19 pandemic due to a disturbed work–life balance is a reason to re-evaluate health policies and involve more hospital care doctors at the frontlines to fight against severe infectious diseases. The results of this study could be used to inform policy makers, healthcare managers, and other stakeholders about the factors that have had profound impacts on GPs' stress levels during the COVID-19 pandemic. [ABSTRACT FROM AUTHOR]

In recent years, a significant import of modern tower yarders has been registered in Bulgaria, where official productivity standards are routinely used for operational planning and control. Given the higher potential of the newer yarder models, the Bulgarian forestry sector has started a review of the older productivity standards dating back to the 1970s. This new endeavor has offered an ideal opportunity for gauging the effect of technological progress in yarder technology. Therefore, the authors have used the very first results achieved during the development of the new standards for conducting a preliminary quantitative comparison between older and newer yarder types. Modern yarders (e.g., Konrad Mounty 4000) are much faster than the older ones (e.g., Koller K300), and their time consumption per cubic meter is half as large, especially on longer distances. At short distances, however, their performance evens out. Regardless of the distance, the installation time of the Konrad Mounty 4000 is twice as short. As they are largely automated, the new machines can be manned by smaller crews (e.g., two workers instead of three) and are easier and safer to operate. Finally, the new machines are equipped with built-in loaders and processors, which allows them to integrate delimbing, crosscutting and stacking within the same work cycle. With older models, a separate team must be deployed for those tasks. [ABSTRACT FROM AUTHOR]

In order for a strain to be considered a probiotic or suitable plant bioprotective agent, it must have proven antimicrobial activity against pathogenic bacteria and phytopathogenic fungi. Bacillus amyloliquefaciens M exhibited significantly high antifungal activity against pathogenic fungi of the genera Aspergillus, Penicillium, Fusarium, and Sclerotinia; yeasts of the genera Candida and Saccharomyces; as well as high antibacterial activity against pathogens of the genera Escherichia, Salmonella, Staphylococcus, Listeria, Pseudomonas, and Bacillus. The manifested antimicrobial activity was influenced by the composition of the growth medium. The antifungal activity of the strain was investigated at growth temperatures of 30 °C and 37 °C, and at different pH values in aerobic and anaerobic cultivation, under static and dynamic culturing conditions. High antifungal activity was observed at the 24th h on both growth media (LBG broth and MPB broth) at pH = 6 and pH = 7 in aerobic and anaerobic cultivation. Bacillus amyloliquefaciens M produced antibiotic substances at pH > 5.0, and the antibiotic substances were either secreted into the medium or associated with the cell surface. Four compounds with different antifungal activity and different Rf values were registered through thin-layer chromatography (Rf1 = 0.47; Rf2 = 0.55; Rf3 = 0.67; and Rf4 = 0.75), two of the compounds were ninhydrin-positive. Bacillus amyloliquefaciens M was cultured in a bioreactor with stirring, and the parameters of the growth kinetics and the sporulation kinetics have been modeled. A spore concentrate of Bacillus amyloliquefaciens M has been obtained. In further research, the efficiency of the concentrate as a plant bioactive agent will be tested. [ABSTRACT FROM AUTHOR]

(1) Introduction: The subject of the present study concerns the analysis of the existence and long time evolution of the solar ~200 yr (de Vries/Suess) and ~2400 yr (Hallstadt) cycles during the recent part of the Wurm ice epoch and the Holocene, as well as their forcing on the regional East European climate during the last two calendar millennia. The results obtained here are compared with those from our previous studies, as well as with the results obtained by other authors and with other types of data. A possible scenario of solar activity changes during the 21st century, as well as different possible mechanisms of solar–climatic relationships, is discussed. (2) Data and methods: Two types of indirect (historical) data series for solar activity were used: (a) the international radiocarbon tree ring series (INTCAL13) for the last 13,900 years; (b) the Schove series of the calendar years of minima and maxima and the magnitudes of 156 quasi 11 yr sunspot Schwabe–Wolf cycles since 296 AD and up to the sunspot cycle with number 24 (SC24) in the Zurich series; (c) manuscript messages about extreme meteorological and climatic events (Danube and Black Sea near-coast water freezing), extreme summer droughts, etc., in Bulgaria and adjacent territories since 296 and up to 1899 AD, when the Bulgarian meteorological dataset was started. A time series analysis and χ2-test were used. (3) Results and analysis: The amplitude modulation of the 200 yr solar cycle by the 2400 yr (Hallstadt) cycle was confirmed. Two groups of extremely cold winters (ECWs) during the last ~1700 years were established. Both groups without exclusion are concentrated near 11 yr sunspot cycle extremes. The number of ECWs near sunspot cycle minima is about 2 times greater than that of ECWs near sunspot cycle maxima. This result is in agreement with our earlier studies for the instrumental epoch since 1899 AD. The driest "spring-summer-early autumn" seasons in Bulgaria and adjacent territories occur near the initial and middle phases of the grand solar minima of the Oort–Dalton type, which relate to the downward phases and minima of the 200 yr Suess cycle. (4) Discussion: The above results confirm the effect of the Sun's forcing on climate. However, it cannot be explained by the standard hypothesis for total solar irradiation (TSI) variations. That is why another hypothesis is suggested by the author. The mechanism considered by Svensmark for galactic cosmic ray (GCR) forcing on aerosol nuclei was taken into account. However, in the hypothesis suggested here, the forcing of solar X-ray flux changes (including solar flares) on the low ionosphere (the D-layer) and following interactions with the Earth's lithosphere due to the terrestrial electric current systems play a key role for aerosol nuclei and cloud generation and dynamics during sunspot maxima epochs. The GCR flux maximum absorption layer at heights of 35–40 km replaces the ionosphere D-layer role during the sunspot minima epochs. [ABSTRACT FROM AUTHOR]

The present research aimed to characterize the genetic diversity and relationships among extant Arabian horse sire lines in Bulgaria, using 15 equine microsatellite markers. The evaluation included 537 Arabian horses representing nine sire lines (SAKLAWI I, LATIF, SEANDERICH, IBRAHIM, SHABAB, DJEBEL MOUSA, KUHAILAN AFAS, BAIRACTAR, and SARHAN). The obtained results indicated that within these lines, the mean number of alleles ranged from 4.15 in SARHAN to 5.54 in SAKLAWI I and LATIF. The mean expected heterozygosity (He) ranged from 0.54 in the SEANDERICH line to 0.67 in SAKLAWI I. The inbreeding coefficient for the entire Arabian populations was rather low: FIS = −0.109, fluctuating from −0.204 in SHABAB to −0.041 in SAKLAWI I. The mean genetic differentiation, FST, was 0.096, demonstrating that nearly 90% of the total genetic variation was due to genetic differentiation within each population. STRUCTURE analysis indicated a genetic similarity between SHABAB and LATIF, between IBRAHIM and KUHAILAN AFAS, as well as between SAKLAWI I, SEANDERICH, and BAIRACTAR. This study of the genetic diversity of Arabian sire lines in Bulgaria can assist in developing a national strategy for the exclusion of non-purebred animals from breeding programs in order to preserve the genetic profile of the original Arabian lines. [ABSTRACT FROM AUTHOR]

Rosa centifolia L. and Rosa gallica L. (Rosaceae) are grown as raw materials for valuable essential oils and hydrosols. There are scarce data about the biological activities and the genoprotective potential of the hydrosols of these roses. The aim of the study was to provide information on their cytotoxic/genotoxic activity and anti-cytotoxic/anti-genotoxic capacity against mutagenic N-methyl-N′-nitro-N-nitrosoguanidine (MNNG). The evaluation was performed using classical tests for chromosomal aberrations and micronuclei in the higher plant Hordeum vulgare and human lymphocyte test systems. The experimental schemes included combined hydrosol and mutagen treatment. Both hydrosols (6, 14, 20%) had no cytotoxic effect on barley and showed low genotoxicity in both test systems as the injuries were enhanced to a lesser extent compared to the controls. Lymphocytes were more susceptible than H. vulgare. Under the conditions of combined treatment, it was found that the two hydrosols possessed good anti-cytotoxic and anti-genotoxic potential against MNNG. Both rose products exerted genoprotective potential to a similar extent, decreasing the frequencies of aberrations in chromosomes and micronuclei to a significant degree in both types of cells when non-toxic concentrations of hydrosols were applied before MNNG. This was performed both with and without any inter-treatment time. The observed cytoprotective/genoprotective potential suggests that these hydrosols are promising for further application in phytotherapy and medicine. [ABSTRACT FROM AUTHOR]

The paper's main objective is to demonstrate the trading and flexibility of services amongst TSOs, DSOs, and Prosumers in a transparent, secure, and cost-effective manner using Blockchain-based TSO-DSO flexibility marketplace (EFLEX). The aim is to look for ways to help DSOs/TSOs be more flexible and more directly engaged in managing energy flows on the network. EFLEX will streamline the needs of both TSO and DSO on the same platform. Based on the paper's proposed services, the pilot service demonstration will be carried out in Bulgaria and Romania, and the main focus will be on congestion management, TSO-DSO Coordination, and Marketplace. The proposed objective is achieved by using Blockchain-based smart contracts and distributed ledger technology. [ABSTRACT FROM AUTHOR]

Simple Summary: In this study, we investigate the availability and access to orphan drugs for rare cancers in Bulgaria, aiming to address the urgent need for improved treatment access for this vulnerable population. By comparing data from European and national sources, we aimed to assess the availability, delays, and budgetary impact of these drugs. Our findings reveal significant disparities in their access and highlight the pressing need for targeted policies to address these inequalities. This research contributes valuable insights into the challenges faced by rare cancer patients and we call for focused efforts at both the European and national levels to ensure equitable access to treatment. Rare cancers are defined by an annual incidence of fewer than 6 per 100,000. Bearing similarities to rare diseases, they are associated with substantial health inequalities due to diagnostic complexity and delayed access to innovative therapies. This situation is further aggravated in Southeastern European countries like Bulgaria, where limited public resources and expertise underscore the need for additional policy and translational research on rare cancers. This study aimed to explore the availability and access to orphan drugs for rare cancers in Bulgaria for the period of 2020–2023. We cross-compared data from both the European Union and national public sources to evaluate the number of available and accessible orphan drugs for rare cancers, the delay from market authorization to reimbursement, the dynamics of public expenditures, and regional disparities in access across the country. We juxtaposed the main characteristics of oncological and non-oncological orphan drugs as well. Only 15 out of 50 oncological orphan drugs that were authorized by the European Medicine Agency were accessible for rare cancer patients in Bulgaria. The median delay between market authorization and inclusion in the Bulgarian Positive Drug List was 760 days. The total expenditures for all orphan drugs for rare cancers amounted to EUR 74,353,493 from 2020 to 2023. The budgetary impact of this group rose from 0.24% to 3.77% of total public medicinal product expenditures for the study period. Rare cancer patients represent a vulnerable population that often faces limited to no access to treatment. We call for targeted European and national policies to address this major inequality. [ABSTRACT FROM AUTHOR]

In the present contribution, we report the results from a study on the ancient technology used to create decorative color plasters in the Thracian tomb near the village of Alexandrovo, Bulgaria. A series of fragments of red, black, grey, white and brown colored lime plasters from the dromos and funeral chamber were investigated by laser-induced breakdown spectroscopy, X-ray diffraction analysis, infrared spectroscopy, paramagnetic electron resonance spectroscopy and differential scanning calorimetry. Based on the combined analytical data, it was possible to identify the pigments, fillers and other materials in the composition of the decorative plasters in the interior, as well as to clarify the technological features related to the plaster creation. The results demonstrated that the murals were implemented on two layers in the case of white, black, grey and brown decoration—first coarse mortar, followed by a white, fine mortar, which usually was made of calcite. In the case of red decoration, a pigment was added to the fine mortar to achieve a colored surface. The pigments were identified as mostly traditional mineral pigments—calcite, kaolinite, red natural ochres (colored earth), brown colored earth and black pigment (amorphous C). The use of the fresco technique is implied by the major participation of calcite and the absence of organic binder in all of the painting layers. [ABSTRACT FROM AUTHOR]

The migration of 32 elements from natural zeolitized tuffs from the Beli Plast and Golobradovo deposits (Bulgaria) was determined in ultrapure, tap, mineral, and coal mine waters in order to evaluate their desorption and adsorption properties. The tuffs are Ca-K-Na and contain clinoptilolite (90 and 78wt.%, respectively), plagioclase, sanidine, opal-CT, mica, quartz, montmorillonite, goethite, calcite, ankerite, apatite, and monazite. The desorption properties are best revealed during the treatment of ultrapure, tap, and mineral water, whereas the adsorption properties are best manifested in coal mine water treatment. The concentrations of Al, Si, Fe, Na, Mn, F, K, Pb, and U increase in the treated ultrapure, tap, and mineral water, while the content of K, Be, Pb, and F increase in the treated mine water. The tuffs show selective partial or complete adsorption of Na, Mg, Sr, Li, Be, Mn, Fe, Co, Ni, Cu, Zn, Al, Pb, U, and SO42−. They demonstrate the ability to neutralize acidic and alkaline pH. Sources of F are presumed to be clinoptilolite and montmorillonite. The usage of zeolitized tuffs for at-home drinking water treatment has to be performed with caution due to the migration of potentially toxic and toxic elements. [ABSTRACT FROM AUTHOR]

Crithmum maritimum L. is a perennial halophyte plant that is a medicinal herb known by people from different cultures since ancient times. However, the therapeutic potential of this halophyte has not been completely investigated, and the scientific data on it are limited. The purpose of the present study was to estimate the chemical composition of the essential oil (EO) obtained from the aerial parts of Crithmum maritimum L. growing wild in Bulgaria, as well as the histolocalization of secretory structures for the synthesis and accumulation of volatile oils. The results obtained on the EO composition of Bulgarian Crithmum maritimum L. provide an opportunity to reveal potential future applications in various fields, such as medicine, pharmacy, agriculture, food, and the cosmetic industry. Gas chromatography with mass spectrometry was performed to assess the chemical profile of the isolated EO. The phenylpropanoid dillapiole was identified as the major compound in the EO, accounting for 34.09% of the total EO. Monoterpene hydrocarbons represented 62.07% of the total oil composition. γ-Terpinene, D-limonene, and β-pinene were the most abundant monoterpene hydrocarbons in the composition of the EO. In addition, histochemical localization of EO in the stem and leaves of Crithmum maritimum L. was carried out. The secretory structures were located in the cortical region of the stem and in the mesophyll tissues of the leaves in the form of secretory ducts. The performed histochemical analysis confirmed the lipophilic nature of the secretion from the duct cells. This is the first report related to the histolocalization and chemical composition of the EO from Bulgarian Crithmum maritimum L. Furthermore, our data indicate some potential possibilities for the evaluation of the therapeutic activity of the EO obtained from this plant species and outline its future applications as a therapeutic agent. Also, the EO from the studied halophyte plant has prominent potential to be used as a biopesticide, which is an environmentally friendly option compared to standard pesticides. [ABSTRACT FROM AUTHOR]

Gene therapies (GTs) have recently emerged as revolutionary personalized therapeutic options. Despite their promising potential, challenges such as uncertainty regarding long-term health benefits and safety, along with extreme price tags, pose significant obstacles to patient access. Within the EU, the European Medicines Agency plays a pivotal role with regards to GT market authorization. However, national authorities are responsible for pricing and reimbursement, which results in fragment patient access within the EU. This study aimed to provide an overview of the complex landscape of post-market authorization accessibility for GT products in Bulgaria, comparing it with neighboring EU countries. We applied a mixed-methods approach, including desk research, public data requests, and list price comparisons. As of 1 April 2023, 14 GTs had a valid market authorization at the EU level. In Bulgaria, Kymriah® was the only GT included in the Positive Drug List (PDL), with an official list price of EUR 335,636.94. Similar results were found in Romania, whereas five GTs were included in Greece's PDL. Additionally, Zolgensma® was found accessible in Bulgaria through an alternative individual access scheme at an estimated price of EUR 1,945,000.00. In conclusion, this study emphasized targeted policy interventions to address health inequalities and to ensure timely access to GTs within the EU. [ABSTRACT FROM AUTHOR]

An experiment was carried out in the Institute of Animal Science—Kostinbrod, Bulgaria, to investigate the growth performance of male layer-type chickens (Lohmann Brown Classic), raised to 6 and 9 weeks of age, to evaluate the economic aspects of this rearing, as well as to present changes in the quality characteristics of the meat during frozen storage. The chickens were reared in a controlled microclimate with an initial stocking density of 9 birds/m2. After 6 weeks of age, fragmentation of the stocking density was applied, and then it diminished to 3 birds/m2. The chickens were slaughtered at 6 and 9 weeks of age. Ten 9-week-old chickens were subjected to carcass analysis. Meat quality parameters (pH, color), degree of proteolysis (free amino groups), and lipid oxidation (content of peroxides and TBARS) were assessed in fresh breast and thigh meat (0 d) and in samples stored for 60 and 120 days at −18 °C in chickens slaughtered at 6 and 9 weeks old. The mean live weight of the male layer-type chickens at 6 weeks was 608.81 g, while the 9-week-old chickens reached 1115.93 g. The feed conversion ratio (FCR) for the whole period of rearing was 2.75. There were no considerable deviations in the meat traits, indicating quality deterioration over the course of the frozen storage. There was a significant increase in the pH of the breast and thighs, reaching maximum values for 60 days of storage in the 6-week-old chicks, while in the 9-week-old birds, pH peaked in the samples stored for 120 days. The changes in the dynamics of pH corresponded to those of proteolysis. There was an increase in lightness (L*), allowing for higher values in the samples stored for 60 days to be reached regardless of the type of meat and age of the chickens. The content of the peroxides increased considerably for 60 days of frozen storage and decreased afterwards. During storage, there was a constant increase in the secondary products of lipid oxidation. Our results indicated that the application of practices such as the fragmentation of stocking density and finding the suitable age for slaughter have significant importance for the profitability of producing meat product from male layer-type chickens. We found that rearing this type of bird until 9 weeks of age resulted in lower costs and higher economic efficiency. [ABSTRACT FROM AUTHOR]

Wildfires are a common disturbance factor worldwide, especially over the last decade due to global climate change. Monitoring postfire forest regrowth provides fundamental information needed to enhance the management and support of ecosystem recovery after fires. The purpose of this study is to propose an algorithm for postfire forest regrowth monitoring using tasseled-cap-derived indices. A complex approach is used for its implementation, for which a model is developed based on three components—Disturbance Index (DI), Vector of Instantaneous Condition (VIC), and Direction Angle (DA). The final product—postfire regrowth (PFIR)—allows for a quantitative assessment of the intensity of regrowth. The proposed methodology is based on the linear orthogonal transformation of multispectral satellite images—tasseled cap transformation (TCT)—that increases the degree of identification of the three main components that change during a fire—soil, vegetation, and water/moisture—and implies a higher accuracy of the assessments. The results provide a thematic raster representing the intensity of the regrowth classes, which are defined after the PFIR threshold values are determined (HRI—high regrowth intensity; MRI—moderate regrowth intensity; and LRI—low regrowth intensity). The accuracy assessment procedure is conducted using very-high-resolution (VHR) aerial and satellite data from World View (WV) sensors, as well as multispectral Sentinel 2A images. Three different forest test sites affected by fire in Bulgaria are examined. The results show that the classified thematic raster maps are distinguished by a good performance in monitoring the regrowth dynamics, with an average overall accuracy of 62.1% for all three test sites, ranging from 73.9% to 48.4% for the individual forests. [ABSTRACT FROM AUTHOR]

Throughout history, ceramics have been the most abundant artifacts in archaeological discoveries. Within the Neolithic period in present-day Bulgaria, skilled artisans applied additional materials to decorate their pottery, evolving in composition and application techniques such as painting or incrustation. This study is focused on the investigation of white pigments used in decorating Early and Late Neolithic pottery from Madzherito, Kaloyanovets, and Hadzhidimitrovo—archaeological sites located in the Thracian Valley, Central South Bulgaria, affiliated with the cultural groups of Karanovo I and IV. Thirteen ceramic sherds were investigated through archaeometric techniques, including Fourier-transformed infrared spectroscopy in attenuated total reflection mode (ATR-FTIR) and laser-induced breakdown spectroscopy (LIBS). LIBS data underwent further analysis using principal component analysis (PCA). The results revealed that calcite, enriched with diverse fillers like quartz, clays, feldspars, and metal oxides, was the primary raw material for white decoration throughout the entire period. Talc emerged as an addition to calcite in the paint of two Early Neolithic sherds. The presence of hydroxyapatite and kaolinite in Late Neolithic pottery was also observed. The inclusion of supplementary ingredients in the primary formula for crafting white decorations signifies either the emergence of novel trends in manufacturing techniques or serves as evidence of vessels imported from adjacent territories. [ABSTRACT FROM AUTHOR]

The present study aims to elucidate the metabolomic profile of Arthrospira platensis grown in a bioreactor in Bulgaria. The results show that Arthrospira platensis has a high content of mannose, 137.02 mg g−1, and vitamin A (retinol)—10.3 μg/100 g. High concentrations of calcium, sulfur, and zinc distinguish its elemental composition. The freeze-dried powder contained 15.81 ± 0.45% dietary fiber, 50.16 ± 0.25% total protein content, and 1.22 ± 0.11% total fat content. Among the unsaturated fatty acids with the highest content is α-linolenic acid (25.28%), while among the saturated fatty acids, palmitic acid prevails (22.55%). Of the sterols in the sample, β-sitosterol predominated. There is no presence of microcystins LR, RR, YR, and nodularin. Therefore, Arthrospira platensis grown in a Bulgarian bioreactor is safe for use in the pharmaceutical and food industries. Many of the organic compounds found have applications in medicine and pharmacology and play an important role in biochemical processes in the body. Therefore, Arthrospira platensis grown in Bulgaria has a high potential for use as an independent food supplement or in combination with other natural products. [ABSTRACT FROM AUTHOR]

Stachys scardica Griseb. is a Balkan endemic species listed in The Red Data Book of Bulgaria with the conservation status "endangered". Successful micropropagation was achieved on MS medium supplemented with 1.5 mg/L benzyladenine (BA), followed by a subsequent ex vitro adaptation in an experimental field resulting in 92% regenerated plants. Using nuclear magnetic resonance (NMR), phenylethanoid glycosides (verbascoside, leucosceptoside A), phenolic acids (chlorogenic acid), iridoids (allobetonicoside and 8-OAc-harpagide), and alkaloids (trigonelline) were identified, characteristic of plants belonging to the genus Stachys. High antioxidant and radical scavenging activities were observed in both in situ and ex vitro acclimated S. scardica plants, correlating with the reported high concentrations of total phenols and flavonoids in these variants. Ex vitro adapted plants also exhibited a well-defined anti-inflammatory potential, demonstrating high inhibitory activity against the complement system. Employing a disk diffusion method, a 100% inhibition effect was achieved compared to positive antibiotic controls against Staphylococcus epidermidis and Propionibacterium acnes, with moderate activity against Bacillus cereus. The induced in vitro and ex vitro model systems can enable the conservation of S. scardica in nature and offer future opportunities for the targeted biosynthesis of valuable secondary metabolites, with potential applications in the pharmaceutical and cosmetic industries. [ABSTRACT FROM AUTHOR]