Abstract: Humanity continues to degrade natural capital, threatening its long-term sustainability. This more and more categorically imposes the need to create a specific green infrastructure - a response to the natural solutions to the accumulating problems (environmental pollution, floods, natural disasters and cataclysms). The failure of decisions to pay sufficient attention to ecological consequences and to apply systematic measures of high quality are among the main reasons for the current situation in most ecosystems. The fast-paced and highly mechanized way of life of modern man creates the illusion of remoteness from the natural world. Yet all human activity depends entirely on ecosystems and their functions and at the same time has (threatening) impacts on them. Therefore, the achievement of greater efficiency in the use of natural resources and the creation of suitable ecological living conditions are critically important goals both for Europe and for the whole world. Green Infrastructure (GI) is a successfully tested tool for providing environmental, economic and social benefits through environmentally sound solutions. Such a tool helps to understand the values provided by nature to human society and mobilizes investments for their maintenance and growth. PubDate: Wed, 29 Mar 2023 00:00:00 GMT
Abstract: In this study we developed thermodynamic models for solid-liquid equilibrium for mixed systems HF-NaF-H2O and HF-KF-H2O up to 2 m HF at T = 25oC. Models are developed on the basis of Pitzer ion interactions approach. The recommendations on mean activity coefficients (γ±) have been used to construct the model for HF-H2O system. The models for binary systems NaF-H2O and KF-H2O are taken from our previous study in the same journal [Donchev et al. ASN (2021) 8(2), 1-15]. To parameterize models for ternary systems we used the available solubility data, i.e. on the basis of solubility approach. The thermodynamic solubility products (as ln Kosp) of precipitating in mixed systems double salts [NaF.HF(cr), and KF.HF(cr)] have been determined on the basis of evaluated model ion interaction parameters and using experimental m(sat) solubility data. The model is in a good agreement with experimewnt solubility data in the systems HF–NaF–H2O and HF–NaF–H2O up to maximum HF molality of 2 mol·kg−1. At higher acid molality the model predicts much higher solubility of double salts (NaF.HF(cr) and KF.HF(cr) for both mixed systems. It was concluded that not a correct raw data for binary HF–H2O system used in parameterization are the main reason for concentration restriction of mixed HF models presented here. PubDate: Wed, 29 Mar 2023 00:00:00 GMT
Abstract: Bulgaria is a country with an extremely diverse nature. Unlike a number of European countries, Bulgarian nature is relatively well preserved. For the purposes of its protection, a network of protected areas was created, which occupy 5.3% of the country’s territory. Bulgaria also participates in a number of international initiatives, which put about 1/3 of the territory of Bulgaria under protection of the natural environment. According to the Protected areas Act in Bulgaria, 6 categories are distinguished - national parks, natural parks, reserves, maintained reserves, protected localities, natural attractions. Among them, important resources for the development of tourism are national parks, natural parks, protected localities and natural attractions. They represent unique sites for the development of alternative forms of tourism such as ecological, cultural-cognitive, route-cognitive tourism, etc. On the other hand, reserves and maintained reserves prohibit tourism activities. The network of protected areas is unevenly developed throughout the country. It is better represented in the mountainous areas, and in the plain parts of the country it is more limited due to the strong anthropogenic changes and the pressure from various human activities. In connection with the preserved nature, the mountains are preferred sites for tourism. The contribution of the protected areas in this regard is significant.Stara planina tourist region is among the country’s tourist areas with well-defined mountainous characteristics. This is an important prerequisite both for the preservation of nature and for the formation of a suitable environment for recreation and tourism, and the mentioned directions are mutually bound.The purpose of this article is to valorize the protected areas in Stara Planina tourist region and to highlight the possibilities for their current and future use for the development of tourism. PubDate: Wed, 29 Mar 2023 00:00:00 GMT
Abstract: The report reveals the impact of tourism on changing national identity. The interaction between tourism and cultural identity as social phenomena is noted. Globalization as a prerequisite for cultural disorientation is examined. The concept of anthropotok, as a mass self-sustaining process of identity change, is examined. PubDate: Wed, 29 Mar 2023 00:00:00 GMT
Abstract: The purpose of the present study was to gather information about the effects of the herb Levisticum officinale (lovage) and of its phenolic ingredients and to elucidate the potential health benefits of the plant in relation to its polyphenolic content. The study was performed by searching different internet-based databases (Google Scholar, ScienceDirect, PubMed, etc.).Levisticum officinale (lovage) is a perennial aromatic plant from the Apiaceae family. This herb is rich in essential oil and is widely used as a seasoning for culinary purposes. Lovage contains up to 860 mg GAE/100 g fresh weight phenolic substances as well. Polyphenols in L. officinale belong to the classes of flavonoids (quercetin, rutin, kaempferol and anthocyanins) and phenolic acids (chlorogenic, neochlorogenic, ferulic, gallic, ellagic). They contribute to potent antioxidant properties of the plant. Anti-inflammatory, anticancer, neuroprotective, antidiabetic, antibacterial, hepatoprotective and other properties of L. officinale extracts have also been demonstrated. Phenolic substances abundant in lovage have shown to be protective in models of osteoporosis and different cardiovascular diseases as well.The information confirms our assumption that Levisticum officinale is not only an useful and pleasant-tasting Mediterranean-cuisine seasoning but also a herb that can contribute to the healthy lifestyle. PubDate: Wed, 29 Mar 2023 00:00:00 GMT
Abstract: Tourism is one of the fastest growing industries of the new millennium. Bulgaria is a destination with an extremely large variety of natural and anthropogenic tourism resources and a relatively well-developed tourism sector of the economy, which brings significant income to the country’s economy. Varna tourist region is one of the leaders in the development of tourism, both for sea vacations and specialized types of tourism. Despite the great potential of the country and the researched tourist areas in particular, there are a number of problems related to uneven tourist development, seasonality, deteriorated tourist infrastructure and the quality of the services offered. The purpose of this paper is to study the current state of tourism and the opportunities for its development in the region. PubDate: Wed, 29 Mar 2023 00:00:00 GMT
Abstract: The concept of sustainable development can play a key role for various knowledge-based sectors, a major factor in the educational system, focused on addressing the problems that exist and preventing new social, economic and environmental ones.The article examines the definition of sustainability, the point of learning aimed at environmental sustainability. The new European Sustainability Competence Framework that outlines the competencies necessary for the ecological transition, including critical thinking, initiatives, conservation of nature and taking responsibility for the negative impact of everyday actions and decisions on the environment and climate worldwide, has been examined here. PubDate: Wed, 29 Mar 2023 00:00:00 GMT
Abstract: Opuntia fragilis (Nutt.) Haw. (Cactaceae) is the smallest and most cold-hardy species of genus Opuntia in North America. In Bulgaria it is grown as an ornamental plant, but in 2019 a population of this species was discovered by other researchers in natural habitats in Lozenska Mt (Western Bulgaria) at 630–660 m a.s.l. on an area (extent of occurrence) of ca. 100 m2. In July 2020, we established a population of this species on the Black Sea coast near the town of Primorsko (Eastern Bulgaria) at 5 m a.s.l. on an area of ca. 300 m2. The distance between the two populations is 360 km in a straight line and their origins are independent of each other. The two localities of this species are so far the only ones described not only for the territory of Bulgaria, but also for Europe.Data are given on the conditions characterizing each of the localities. The possible reasons for the appearance in natural habitats of this alien plant species for the Bulgarian flora are considered. The impacts and threats this species may have on biodiversity in natural habitats are indicated. Measures have been proposed to control the populations of the species. PubDate: Wed, 29 Mar 2023 00:00:00 GMT
Abstract: Traditional knowledge is of real danger to be lost in modern society. This research is a part of an ethnobotanical survey aimed on documentation of current status of folk medicine in Central and Northeastern Bulgaria. Semi-structured interviews with local knowledgeable persons were provided. Quantitative ethnobotanical indices consisting of Fidelity level (FL) and Informant consensus factor (ICF) were calculated as indicatives of local importance of species and prevalent uses of species. The respondents reported 15 category uses: to treat 12 health disorders, for prophylaxis/immune stimulation, other health connected conditions and plants included in the diet as food/spices. The highest number of plants was used for the treatment of gastrointestinal diseases (65.9%), cardiovascular problems (53.4%) and urinary system problems (46.6%). It should be noted that many herbal medicines are related to disease prevention (52.3%). Maximum FL value (100%) of Hypericum perforatum for digestive and nervous system disorders and Thymus sp. for respiratory system diseases was calculated. Numerous species and specific applications were listed in the paper, contributing to the base ethnobotanical data. Specific use categories indicate most spread health disorders and proved treatments in the studied regions. Results also reflect the growing interest in disease prevention (immune stimulation) and a healthy diet. PubDate: Tue, 01 Nov 2022 00:00:00 GMT
Abstract: The most commonly used method to control wheat powdery mildew is by fungicides. The aim of the present study is to determine the duration of the fungicide activity of three fungicides: azoxystrobin; triadimenol; tebuconazole+spiroxamine+triadimenol. They were applied in three concentrations in phenophase 3-4 leaf of susceptible wheat variety. After treatment, each day one pot of the tested fungicide concentrations was inoculated with Blumeria graminis f. sp. tritici. When using azoxystrobin at concentrations of 0.2%, 0.4%, 0.8%, symptoms of powdery mildew appeared on plants inoculated with Blumeria graminis f.sp. tritici in the next day after treatment. When using triadimenol, first symptoms appeared in plants inoculated with the pathogen on the next day after applying a concentration 0.12%, on the second day after applying a concentration 0.25% and on the third day after treatment with a concentration 0.5%. With tebuconazole+spiroxamine+triadimenol, first postules appeared on plants inoculated with Blumeria graminis f. sp. tritici on the third day after treatment with a concentration 0.15%, on the 13th day after treatment with a concentration 0.3% and on the 14th day after treatment with a concentration 0.6%. This fungicide at a concentration of 0.6% (13 days) and 0.3% (12 days) has the longest duration of fungicide activity. PubDate: Tue, 01 Nov 2022 00:00:00 GMT
Abstract: Nowadays, an increased interest towards the integration of the concept of ecosystem services has been observed, both in regards to processes related to forest and water resources management, as well as in the context of sustainable development of the economy on a local, regional and national level. In the most common case, what is referred to as forest ecosystem services are possible benefits, which man can reap directly or indirectly from ecosystem functions of forest territories. Therefore, it is of great importance to analyse and assess the interactions between the human factor with the conditions and processes through which forest ecosystems create and sustain ecosystem services. The water ecosystem service provided by forest territory could cause the need to process large amounts of spatial data in the form of forest management and hydrological information, as well as information about sanitary protection zones around water sources, in the context of the administrative territorial division of the country at different levels, creates considerable challenges. The difficulties are due to both the various electronic formats in which the necessary information is maintained, and the need to perform different operations on the input data for the purpose of analysis and decision making. The present paper investigates the possibilities of automating the processing of large volumes of spatial data in the context of the ecosystem water service, provided by forest territories by developing a set of tools operating into the environment of open source GIS. The main purpose is to develop a unified approach based on the use of GIS and suitable for the creation and implementation of methods for analysis and management of processes related to the ecosystem water service provided by forest territories. The approach can be applied in different sectors of the economy, public relations and the environment. PubDate: Tue, 01 Nov 2022 00:00:00 GMT
Abstract: This study is based on observations of MWC560 during the last two observational seasons (2020/2021 and 2021/2022). Other than looking for flickering we were interested in following the variability of brightness in the same period. Looking for similarities in the spectra with other types of stars is also of great interest to us because it could help clarify the stellar configuration of such objects. Our observations during the last two observational seasons of MWC560 confirm the absence of flickering. From the similarities of the gathered spectra of XX Oph and MWC560 we assume that the components in XX Oph are a red giant and a white dwarf, which are also surrounded by a common shell. PubDate: Tue, 01 Nov 2022 00:00:00 GMT
Abstract: At present, the inventory lists of the Myriapoda of many geographical areas in Bulgaria and the comparative analyzes of the similarity between such local faunas are scarce or completely missing. The present paper presents the results of the comparative analysis of α- and β-diversity of the myriapoda communities in natural habitats in two regions in Northeastern Bulgaria – the Shumen Plateau and the Madara Plateau. The compared habitats in these plateaus have similar geographical, soil and climatic conditions, and similar species composition of plant formations. The analysis of the structure of the myriapoda communities included estimation of species diversity by determining the Shannon-Wiever index (H’) and the Berger-Parker index (d). The degree of similarity between the species composition of the communities was analyzed by the Czekanowski-Dice-Sörensen, Jaccard, Bray-Curtis, Horn, Morisita-Horn indices and the corrected Chao-Sörensen and Chao-Jaccard indices. The species diversity of the millipede community in the Shumen Plateau is much greater than that of the Madara Plateau, while the diversity of the centipede communities in the two plateaus does not differ significantly. In both classes the greatest species diversity is registered in deciduous and mixed deciduous-coniferous forests. Chao-Sörensen and Chao-Jaccard indices of similarity for the myriapod communities in these habitats are the highest, approaching 1, in contrast to the other sites where the registered species composition of the centipedes is smaller and the degree of similarity is about 0.6. PubDate: Tue, 01 Nov 2022 00:00:00 GMT
Abstract: Interactions between pentacyclic triterpenes isolated from white birch (Betula pendula Roth.) bark samples from Northeast Bulgaria and bovine serum albumin or human serum albumin were investigated using fluorescence techniques. The experimental results show the formation of complexes between the isolated triterpenes with serum albumins. Quenching of the intrinsic fluorescence of human serum albumins was monitored by emission spectra of varied quencher concentration solutions. By analysing the fluorescence spectra and fluorescence intensity, some parameters of the serum albumins - quencher interaction were determined to evaluate the type of quenching. An extract containing the isolated triterpenes formed complexes with both bovine serum albumin and human serum albumin, leading to quenching the fluorescence of both albumins by a combined quenching mechanism. PubDate: Tue, 01 Nov 2022 00:00:00 GMT
Abstract: An exopolysaccharide (EPS) was isolated from Lactobacillus plantarum Ts and purified by size exclusion chromatography train. L. plantarum showed the highest production (9.4 ± 0.8 g/l) of EPS. Furthermore, L. plantarum was cultured in medium with volume of 5 L and the EPS was extracted by ethanol precipitation. By HPLS analysis demonstrated, that the EPS has two fractions - polymer and olygomer. The molecular mass of the EPS from both fractions is respectively 8.3x104 Da for the greater pic and 5.0x102 Da. Fourier transform infrared spectroscopy analysis showed the presence of hydroxyl and carboxyl groups and glycosidic linkages. TLC analysis indicated that the EPS was a heteropolymer composed of fructose, and sucrose as monomeric constituent units. The strain L. plantarum and pathogenic E. coli 3398, St. aureus 745, B. subtilis 6633, S. typhimurium 3591, L. monocytogenes 863 and E. aerogenes 3691 were tested for their growth utilizing the EPS from L. plantarum as the sole carbon source for its possible use as a prebiotic. L. plantarum exhibited growth in the EPS supplied medium compared with sucrose as carbon source, whereas the pathogenic strains did not grow in the EPS-supplied medium. In vitro evaluations showed that, like other reported polysaccharides, this EPS displayed significant prebiotics properties. PubDate: Tue, 01 Nov 2022 00:00:00 GMT
Abstract: The present development uses the modeling method described in the literature and proposed a new didactic, functional model of the “chemistry training” system in the application of semiotic approaches: semantic, pragmatic, and syntactic. The main objective of creating such a model is to demonstrate the specific activities of the subjects “teacher” and “pupil” when familiarizing themselves with chemical symbols and their study by students. The added new components in the model “Technology of chemistry training”, “Semiotic information” and the clarified links between them, lead to a complete change in the way the described system works. The developed didactic model makes it easy to guess the relationship between a new learning situation and a result, that is, to predict an unknown process or phenomenon. This model makes it possible to formulate a reasoned hypothesis of the study. PubDate: Thu, 28 Jul 2022 00:00:00 GMT
Abstract: In the present study, we report on new localities in Northeastern Bulgaria, where Elaphe sauromates (Pallas, 1814) was recently detected. We registered five Blotched snakes in the region of Shumen town in the period 2018 - 2022. All of the snakes were adults, three were killed by tools impacts and two of them were road kills. To date, the Blotched snake was registered extremely rare and in rather long intervals (of several decades) in the region of Shumen. Our findings indicate that the species currently inhabits the suburban and urban territories near the villages of Ivanski, Radko Dimitrievo and Konyovets. Two of the locations are new for the 10 km grid-system used for standard monitoring of the biodiversity in Bulgaria. PubDate: Thu, 28 Jul 2022 00:00:00 GMT
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