Locations In Bulgaria Research Articles

Winter activity of the snake-eyed lizard Ophisops elegans (Reptilia: Lacertidae) in the northwesternmost part of its range

There is a lack of information for potential winter activity of the snake-eyed lizard Ophisops elegans in Europe, where it has a limited distribution. To test the hypothesis that this species can be active during the winter months, two locations in Bulgaria were chosen. The visits were conducted in January, February and December 2022 near the village of Meden Buk and in December 2022 above the village of Mezek. A total of 19 individuals of O. elegans were recorded. In addition, we confirmed foraging behaviour based on faecal sample collection. To our knowledge, this is the northernmost record of winter activity in the snake-eyed lizard and the first consecutive observation of year-round activity for this species in Europe.

Variation of UV-A/UV-B daily profiles depending on locations and altitude

Solar UV/visible monitoring has increased its importance in the recent years due to the global warming, unexpected atmospheric anomalies and storms, and the increasing needs for additional human protection. In mountain areas with high elevation the interest to UV irradiation measurements is expected to increase due to atmospheric transparency, however frequent events of lightning and risk of equipment failures has to be taken into account. The cost of the UV measurement systems can be greatly reduced by employing low-cost integrated inexpensive digital sensors with on-chip signal conditioning as detectors which are more convenient for field deployment and outdoor measurements. Thus, a compact portable UV/visible sensor equipment is in great demand for annual solar irradiation monitoring and seasonal all-day measurement campaigns. In this work, we report on the development of an in-house portable UV sensor system based on digital sensors with I2C communication, open-source hardware and software. The developed equipment is based on integrated digital sensors (VEML 6075, TSL 2591). It has been developed by employing Wi-Fi ESP 32 microcontroller, ODROID microcomputer and open-source software (InfluxDB and Grafana visualization tool). We investigate the system performance by measuring daily profiles of UV-B/UV-A irradiation in different locations and under different atmospheric conditions in order to evaluate its feasibility for prevention of humans from UV overexposure during outdoor operations. On-field tests are performed for 2 years in 7 different locations in Bulgaria. Interestingly, in downtown during particular days with high traffic an increased UV scattering and absorption due to urban pollution has been observed.

Myopia in Bulgarian school children: prevalence, risk factors, and health care coverage

BackgroundThe prevalence of myopia has increased in recent years, with changes being dynamic and uneven in different regions. The purpose of this study is to evaluate the prevalence of visual impairment caused by myopia in Bulgarian school children, associated risk factors, and health care coverage.MethodsA cross-sectional study among 1401 children (mean age 10.38, standard deviation 2.70) is conducted in three locations in Bulgaria from 2016 to 2020. Refractive error is measured with an auto-refractor in the absence of cycloplegia, the visual acuity is assessed without refractive error correction. A paper-based preliminary questionnaire is used to collect data on previous eye examinations, prescribed optical vision correction, regularity of wearing corrective glasses and risk factors.ResultsChildren with myopic objective refraction ≤ -0.75 D and decimal visual acuity ≤ 0.8 on at least one of the eyes are 236 out of 1401 or 16.85%. The prevalence of myopia varies depending on age, geographical location, and school profile. The rate of myopic children in age group 6–10 is 14.2% compared to 19.9% in age group 11–15. The prevalence of myopic children in the urban populations is 31.4% (capital) and 19.9% (medium-sized town) respectively, and only 8.4% in the rural population. Our results show 53% increase of the prevalence of myopia in the age group 11–15 compared to a 2009 report. The analysis of data associated with health care coverage factors of all myopic pupils shows that 71.6% had a previous eye examination, 43.2% have prescription for corrective glasses, 27.5% wear their glasses regularly. Risk factors for higher odds of myopia are gender (female), age (adolescence), and parents with impaired vision. Residence in a small town and daily sport activities correspond to lower odds for myopia. The screen time (time in front of the screen calculated in hours per day) is self-reported and is not associated with increased odds of myopia when accounted for the other risk factors.ConclusionsThe prevalence of myopia in this study is higher compared to previous studies in Bulgaria. Additional studies would be helpful in planning adequate prevention and vision care.

A contribution to the knowledge on the diet and food preferences of Darevskia praticola (Reptilia: Lacertidae)

The Meadow lizard (Darevskia praticola s.l.) is one of the more poorly-studied lizard species in Europe, and no detailed data on its diet is available. We investigated a total of 180 faecal samples of D. praticola s.l. from two locations in Bulgaria, and conducted a comparison between sex and age groups (adult males, adult females, and immatures). In addition, the correlations between the consumed prey and the available resources were also analysed. Food selectivity was analysed by comparing the faecal samples with pit-fall trap samples on the basis of abundance of prey items from particular operational taxonomic units (OTUs). Results indicate that the diet of the Meadow lizard contains mainly arthropods (insects and spiders) and the most abundant prey items belong to Araneae, Auchenorrhyncha, and Coleoptera. According to the used electivity indices none of the OTUs are highly preferred by D. praticola s.l., but Formicidae are the most avoided OTU for all sex/age groups. Differences in food preferences can be found between adults and immatures, while differences among males and females seem to be insignificant. The lack of clear differentiation between males and females could be a result of their similar size and locomotor ability. In conclusion, our results reveal that Darevskia praticola s.l. is a generalist and it shows no food specialization due to its narrow spatial niche.

Environmental and Anthropogenic Influence on the Core Beneficial Honeybee Gut Microbiota—A Short Communication from Bulgaria

Bees’ and beehives’ health are strongly influenced by the honeybees’ gut microbiota which in turn is strongly dependent on many different factors, including environmental factors as well as anthropogenic pressure. In this study, in four locations in Bulgaria differing strongly in environmental conditions and anthropogenic pressure, an assessment was made using several obligatory core symbiont species and genera for reference, such as Lactobacillus sp., Bifidobacterium sp., Snodgrassiella alvi, Gilliamella apicola, Frishella perrara, and Commensalibacter sp., as well as an observation of the overall number of species. A snapshot of the relative abundances of the total number of species and the core species was made using a next-generation sequencing (NGS)-based metagenomic approach using the Illumina 2 × 250 bp paired-end platform. It was found that the two forms of anthropogenic pressure, the agricultural and the urban/industrial, have distinct effects, affecting different core genera and species. It was also demonstrated that both types of anthropogenic pressure cause a reduction in the overall number of bacterial species.

Development of the cherry leaf spot epidemics in different regions of Bulgaria

A 2-year research on the epidemics of the cherry leaf spot (CLS) was conducted in unsprayed cherry orchards at two locations in Bulgaria (Krichim and Gabarevo). The primary infections for both years at Gabarevo happened in mid-May during fruit development. In Krichim during 2018 the first symptoms of the disease appeared in early June (fruit ripening), while in 2019 they became evident in the second half of May (fruit development). In both locations and years, the period of a rapid increase in the CLS incidence and defoliation was from mid-June till late July. The maximum of the disease incidence and defoliation was observed in early September. More seasonal rather than regional trend in the disease dynamics was observed. In 2018 the orchards in both locations exhibited delayed the CLS progression compared to 2019 due to the relatively dry conditions in April and May. The higher disease incidence and defoliation in 2019 could be assigned to the high infection background and weather conditions in the beginning of the growing season.

A Snapshot Picture of the Fungal Composition of Bee Bread in Four Locations in Bulgaria, Differing in Anthropogenic Influence.

Information about the fungal composition of bee bread, and the fermentation processes to which the fungi contribute significantly, is rather scarce or fragmentary. In this study, we performed an NGS-based metagenomics snapshot picture study of the fungal composition of bee bread in four locations in Bulgaria during the most active honeybee foraging period at the end of June 2020. The sampling locations were chosen to differ significantly in climatic conditions, landscape, and anthropogenic pressure, and the Illumina 2 × 250 paired-end reads platform was used for amplicon metagenomics study of the ITS2 region. We found that some of the already reported canonical beneficial core fungal species were present within the studied samples. However, some fungal genera such as Monilinia, Sclerotinia, Golovinomyces, Toxicocladosporium, Pseudopithomyces, Podosphaera and Septoriella were reported for the first time among the dominant genera for a honeybee related product. Anthropogenic pressure negatively influences the fungal composition of the bee bread in two different ways—urban/industrial pressure affects the presence of pathogenic species, while agricultural pressure is reflected in a decrease of the ratio of the beneficial fungi.

RECORDS OF IXODID TICKS ON WILD BIRDS IN BULGARIA

Background: Ixodid ticks are widely studied due to their epidemiological and epizootic importance. It is of great value to know vertebrate host preferences of ticks in order to understand their ecological relationships and distribution. Earlier studies report birds as important hosts of Ixodid tick and a total of 136 ticks species have been frequently found in birds worldwide. However, only few studies related to host preferences of ticks among wild birds in Bulgaria were conducted till now. Aim: To obtain new data on the host preferences of ixodid ticks among wild birds at three locations in Bulgaria. Material and methods: The study was conducted between 2010 – 2020 in three sites in Bulgaria – Biological Experimental Station Kalimok (Silistra region), near Brodilovo village (Burgas region), and the city of Sofia (city park). The birds were caught by mist nets and inspected for ticks. Ticks found were removed by fine tweezers or a special removal tool for ectoparasites. Tick identification was based on external morphological characteristics. Results: A total of 2419 individual birds belonging to 78 species were examined. Of these, 70 individuals (16 species) carried ticks, thus representing 2.9% infestation rate. A total of 262 ticks were collected and identified as: Ixodes ricinus, Hyalomma marginatum, Haemaphysalis punctata, Hae. concinna, Hae. sulcata and two specimens could only be identified to the genus Haemaphysalis. Ixodes ricinus was the most commonly encountered tick (224/262), predominantly nymphs, followed by Hyalomma marginatum (27/262). The highest prevalence of tick infestation was observed among the Eurasian Blackbird, Turdus merula (28.6%), followed by the common nightingale, Luscinia megarhynchos (12.9%) and the common chaffinch, Fringilla coelebs (11.3%). These three bird species harboured the majority of ticks on their heads – some single individuals were infested by 10 up to 25 ticks per bird. Conclusion: Ixodes ricinus was found as the predominant tick species in this study. Nymphs were the most frequently observed stage. Infesting both birds and humans, this tick species has the potential to spread local tick-borne infections.

Medical and cosmetic center or beauty salon

Provoked by the controversy over the difference between a beautician and a medical beautician, we decided to conduct a survey using the following methods: literature, magazines, documents and anonymous surveys. The subject of our study are 100 male and female respondents aged 16 to 60 + from different locations in Bulgaria.

Comparative Study on the Phytochemical Composition and Antioxidant Activity of Grecian Juniper (Juniperus excelsa M. Bieb) Unripe and Ripe Galbuli.

Grecian juniper (Juniperus excelsa M. Bieb.) is an evergreen tree and a rare plant found in very few locations in southern Bulgaria. The aim of this study was to evaluate the phytochemical content and antioxidant potential of J. excelsa unripe and ripe galbuli from three different locations in Bulgaria. The essential oil content ranged between 1.9% and 5.1%, while the lipid fraction yield was between 4.5% and 9.1%. The content of total chlorophyll was 185.4–273.4 μg/g dw. The total carotenoid content ranged between 41.7 and 50.4 μg/g dw of ripe galbuli, and protein content was between 13.6% and 16.4%. Histidine (5.5 and 8.0 mg/g content range) and lysine (4.0 and 6.1 mg/g) were the major essential amino acids. The antioxidant potential of the 95% and 70% ethanol extracts was analyzed using four different methods. A positive correlation between the antioxidant potential and phenolic content of the galbuli was found. The results obtained in this study demonstrated the differences in phytochemical composition and antioxidant capacity of J. excelsa galbuli as a function of maturity stage and collection locality.

Multivariate assessment of atmospheric deposition studies in Bulgaria based on moss biomonitors: trends between the 2005/2006 and 2015/2016 surveys.

This study aims to investigate the changes in atmospheric deposition trends in Bulgaria, studied using the moss biomonitoring technique since 1995. For the first time, a paired (site-wise) comparison was performed after a critical review of the sampling networks and adjusting for location, the distance between the sampling points, and moss species. Data from the 2005/2006 and 2015/2016 moss surveys were chosen as instrumental neutron activation analysis was employed in both to determine the content of 34 elements (Al, As, Ba, Br, Са, Ce, Cl, Со, Cr, Cs, Fe, Hf, I, K, La, Mn, Na, Nd, Ni, Rb, Sb, Sc, Se, Sr, Ta, Tb, Th, Ti, Tm, U, V, W, Yb, Zn). In addition, Cd, Cu, and Pb were determined using complementary analytical methods: inductively coupled plasma atomic emission spectroscopy in 2015/2016 and atomic absorption spectroscopy in 2005/2006. For the subset of 57 routinely sampled locations in Bulgaria, hierarchical clustering on principal components and multiple factor analysis (MFA) were applied to assess the spatial trends inthe 10years elapsed between the surveys, as well as to characterise the origin of the determined elements. Elevation and distance between the sampling points were used as additional variables in the multiple factor analysis plane to ascertain their effect on the overall variance in the datasets. Distribution maps were constructed to illustrate the deposition patterns for the pollutant Pb. The results were consistent with decreased industrial output in the country, increased coal combustion and transport pollution, and construction of roads.

METER.AC: Live Open Access Atmospheric Monitoring Data for Bulgaria with High Spatiotemporal Resolution

Detailed atmospheric monitoring data are notoriously difficult to obtain for some geographic regions, while they are of paramount importance in scientific research, forecasting, emergency response, policy making, etc. We describe a continuously updated dataset, METER.AC, consisting of raw measurements of atmospheric pressure, temperature, relative humidity, particulate matter, and background radiation in about 100 locations in Bulgaria, as well as some derived values such as sea-level atmospheric pressure, dew/frost point, and hourly trends. The measurements are performed by low-power maintenance-free nodes with common hardware and software, which are specifically designed and optimized for this purpose. The time resolution of the measurements is 5 min. The short-term aim is to deploy at least one node per 100 km2, while uniformly covering altitudes between 0 and 3000 m asl with a special emphasis on remote mountainous areas. A full history of all raw measurements (non-aggregated in time and space) is publicly available, starting from September 2018. We describe the basic technical characteristics of our in-house developed equipment, data organization, and communication protocols as well as present some use case examples. The METER.AC network relies on the paradigm of the Internet of Things (IoT), by collecting data from various gauges. A guiding principle in this work is the provision of findable, accessible, interoperable, and reusable (FAIR) data. The dataset is in the public domain, and it provides resources and tools enabling citizen science development in the context of sustainable development.

ABOVEGROUND DENDROMASS ESTIMATION OF JUVENILE PAULOWNIA SP.

Species of the genus Paulownia have been introduced to Bulgaria since the beginning of the XXthcentury and their multipurpose uses - as ornamental trees, for wood and biomass production- have been tested ever since. We present a study, which examines the early growth of four Paulowniaclones at southern locations in Bulgaria and derives biometric models for dendromass estimationof juvenile Paulownia trees.The data originated from two experimental plantations established on nursery land using one-yearoldin vitro propagated plant material. Forty six, 1 to 3 year-old saplings from two clones of P. tomentosaand two P. elongata × P. fortunei hybrids were sampled. Their stem biomass was modeledas a function of the breast height tree diameter and total tree height or the stem diameter aloneand a set of goodness-of-fit criteria was applied to select the most adequate among the 29 testedformulations. The regression models were fitted in log-transformed form to the logarithm of thestem biomass and MM correction factor for bias was applied to the back-transformed predictiondata. Two allometric relationships were derived, which adequately assess stem dendromass ofyoung Paulownia sp. from easily measurable tree characteristics. Both models are applicable forstem biomass estimation of juvenile Paulownia trees of diameter up to 5 cm and total height upto 3.5 m.

Oenothera speciosa versus Macroglossum stellatarum: killing beauty

Hovering and dead individuals of the diurnal hawk-moth Macroglossum stellatarum (Linnaeus, 1758) (Lepidoptera: Sphingidae) were found with proboscides got stuck into flowers of the ornamental plant Oenothera speciosa Nutt (Onagraceae). The phenomenon was observed in several locations in Bulgaria where the plant has been introduced. Microscopic examination revealed that the reason for this unusual interaction is pubescence of thick-walled basiscopically oriented trichomes in the basal part of the hypanthium and style of the plant. When a foraging moth inserts its proboscis into this area, the tips of the trichomes are inserted into the transverse grooves of proboscis and hamper its back movement. As a result the moths are suspended for a long time, sometimes until death. Other trapped moth species were also observed but they always effected self-release. This plant–insect interaction is also a conservation issue as an estimation of its impact on wild insect populations is lacking.

СУЧАСНИЙ СТАН І ПЕРСПЕКТИВИ АМЕРИКАНСЬКО-БОЛГАРСЬКИХ ВІДНОСИН

The main stages of the relations between the USA and Bulgaria after the fall of the Communist regimes in the Central-Eastern Europe in1989 are clarified. They were the most active in 1990-1992, 2001-2003, 2005-2008 and their intensity depends mostly on the interest of the USA in the promoting their national interests with the help of Bulgaria. It is revealed, that the energetics and defense are the most important issues in the bilateral interaction. Geopolitical location of Bulgaria allows to consider it as a potentially significant element in the hydrocarbons supply in Europe from the Caspian region, Middle East and Russia. USA regard Bulgaria as a main partner in the South-Eastern Europe because of its strong allied position during the conflicts in the Balkans and Middle East and also its stable political development and rapid temps of democratization. Transformation of the American-Bulgarian cooperation during the second B. Borisov cabinet in power (since the November 2014) are analyzed. The key factor of it is the aggressive politics of Russia in the Black Sea Region. This politics obliged US diplomacy to promote the questions of the Bulgaria’s involving in the Southern Gas Corridor project more consistently and its defensive capacity strengthening. In this period position of Bulgaria in the main regional issues mostly corresponds with the American priorities. It concerns such directions as the international sanctions against Russia because of its aggression in Ukraine, the energy and arms diversification, strengthening of the NATO Eastern borders security.

English

Since 2007, when Bulgaria became a full member of the EU and 2012, when Serbia was granted the status of candidate for EU membership, these countries have become very attractive investment destinations. The object of this research is the movements of FDI in the mentioned countries in 2013 and their structure by economic activities. The scientific problem is related to the positive effects of FDI on the host country, making an attractive investment environment, creating incentives for foreign investors and comparing the structure of FDI in Bulgaria and Serbia with simultaneous comparison with the European average. It may be noted that this is a current theoretical and empirical research that deals with modern state of the subject. The necessary quantitative data have been collected using the desk method and using the secondary data source and the method of description as well as the comparative method were used in the ensuing analysis. The aim of the study is to, by applying the above methods, determine the most attractive investment areas, analyze the current investment incentives and provide recommendations on adjustments to be made to improve the actual investment strategies and create attractive investment locations in Bulgaria and Serbia.

Phylogenetic Diversity of Archaea and the Archaeal Ammonia Monooxygenase Gene in Uranium Mining-Impacted Locations in Bulgaria

Uranium mining and milling activities adversely affect the microbial populations of impacted sites. The negative effects of uranium on soil bacteria and fungi are well studied, but little is known about the effects of radionuclides and heavy metals on archaea. The composition and diversity of archaeal communities inhabiting the waste pile of the Sliven uranium mine and the soil of the Buhovo uranium mine were investigated using 16S rRNA gene retrieval. A total of 355 archaeal clones were selected, and their 16S rDNA inserts were analysed by restriction fragment length polymorphism (RFLP) discriminating 14 different RFLP types. All evaluated archaeal 16S rRNA gene sequences belong to the 1.1b/Nitrososphaera cluster of Crenarchaeota. The composition of the archaeal community is distinct for each site of interest and dependent on environmental characteristics, including pollution levels. Since the members of 1.1b/Nitrososphaera cluster have been implicated in the nitrogen cycle, the archaeal communities from these sites were probed for the presence of the ammonia monooxygenase gene (amoA). Our data indicate that amoA gene sequences are distributed in a similar manner as in Crenarchaeota, suggesting that archaeal nitrification processes in uranium mining-impacted locations are under the control of the same key factors controlling archaeal diversity.

Distribution of chestnut blight and diversity of Cryphonectria parasitica in chestnut forests in Bulgaria

SummaryWe surveyed chestnut stands at 18 sites in 11 locations in Bulgaria in 2005 and 2007 for the presence of chestnut blight. We found chestnut blight in seven locations (Belogradchik, Berkovitsa, Brezhani, Barziya, Govezhda, Petrich and Petrovo) but not in four others (Tsaparevo, Kresna, Dupnica and Botevgrad). We successfully isolated Cryphonectria parasitica from cankers on 606 trees with symptoms of chestnut blight and assayed them for vegetative compatibility (vc) types and mating type. Three vc types were identified among the 606 isolates; all three were among the European vc types with known vegetative incompatibility (vic) genotypes. Vc type EU‐12 was the most common, representing 80% of the isolates, and was found at all locations with blight, with the exception of Belogradchik in north‐west Bulgaria, where all isolates were vc type EU‐2. Only one population (Barziya) had more than one vc type, with a combination of EU‐12 and EU‐10 in almost equal frequencies. Similarly, the diversity of mating types was very low. All but three of 536 isolates assayed were in mating‐type MAT‐1; MAT‐2 was only found in one population in the north‐west (Berkovitsa). We inspected 671 bark samples from chestnut blight cankers with stromata of C. parasitica and found perithecia in only 33, of which 28 were from Berkovitsa where MAT‐2 was present. We did not detect hypoviruses in any of the 270 isolates screened using the standard double‐stranded RNA extraction protocol. Similar to results from previous studies in south‐eastern Europe, the diversity of vc types and mating type of C. parasitica in Bulgaria is low, and reproduction of the fungus is mainly asexual. Unfortunately, naturally occurring hypovirulence was not detected. Nevertheless, we observed a small number of superficial cankers typical of those caused by C. parasitica isolates infected with a hypovirus.

Alkaloid Diversity in Galanthus elwesii and Galanthus nivalis

Seventy alkaloids of galanthamine, lycorine, homolycorine, tazettine, haemanthamine, narciclasine, and tyramine types were detected by GC/MS in 25 Galanthus elwesii and seven Galanthus nivalis populations, collected from different locations in Bulgaria. Intraspecies diversity in the alkaloid profiles regarding the main alkaloid types (chemotypes) was observed. Tyramine-type protoalkaloids (namely, hordenine and its derivatives) were dominant in 19 populations of G. elwesii. In other populations of G. elwesii, the plants accumulated mainly homolycorine-, lycorine-, and galanthamine-type alkaloids. The alkaloid profiles of G. nivalis were dominated by narciclasine-, galanthamine-, lycorine-, haemanthamine-, or tazettine-type compounds. Geographical distribution of chemotypes indicated a relationship between populations, since adjacent populations often displayed similar alkaloid profiles. The results from year-to-year sampling and transplantation experiments imply genetic determination of alkaloid synthesis in the two studied species of Galanthus.

Investigation of the molecular and morphological variability in Batrachospermum arcuatum (Batrachospermales, Rhodophyta) from geographically distant locations

Vis M.L., Feng J., Chiasson W.B., Xie S.-L., Stancheva R., Entwisle T.J., Chou J.-Y. and Wang W.-L. Investigation of the molecular and morphological variability in Batrachospermum arcuatum (Batrachospermales, Rhodophyta) from geographically distant locations. Phycologia 49: 545–553. DOI: 10.2216/10-04.1Phylogeographic patterns in Batrachospermum arcuatum were investigated using the mitochondrial intergenic spacer between the cytochrome oxidase subunit 2 and 3 (cox2-3 spacer) from locations worldwide. Sixteen locations were sampled in six regions as follows: three locations in Bulgaria, two in China, three in the northwestern United States, one in New Zealand, six in Hawaii and one in Taiwan. Sequencing of 107 individuals resulted in 12 haplotypes. In the United States and Bulgaria, there was considerable sequence divergence among haplotypes. Likewise in the Hawaiian Islands, there was variation among haplotypes, and each island appeared to have a single haplotype represented. Three closely related haplotypes were present at the Taiwan location. The New Zealand sample was identical to one of the haplotypes from the northwestern United States. Individuals representing the 12 cox2-3 spacer haplotypes were sequenced for the rbcL gene. In the combined analysis, the Hawaii and Taiwan samples were a well-supported clade as were two Bulgaria samples. The US and New Zealand haplotypes formed a well-supported clade and likewise the China samples, but the relationship of the third Bulgaria haplotype to these others was unresolved. The specimens showed morphological variation among localities and regions, but no morphological features appeared to be diagnostic of the molecular results. Batrachospermum arcuatum appears to be a widespread taxon with considerable morphological plasticity that does not coincide with the substantial molecular variation. Alternatively, B. arcuatum may harbour cryptic species. There appears to be a temperate origin of the taxon and a derived group of haplotypes from tropical regions.