Northeastern Bulgaria Research Articles

NUMERICAL SIMULATION OF DOUBLE SKIN FACADES IN WINTER CLIMATES

The presented study reveals the analysis of the thermal behaviour of double skin facades (DSF) in winter conditions, using numerical simulation tools. The aim of the study is the development of a 3D simulation model, capable to evaluate the thermal behaviour of the modular elements in the DSF systems. This is essential requirement in the prediction and visualization of the facade’s thermal behaviour in the design stage and in the assessment of the real behaviour of such facade, when the specified modular elements are changed by the customer. The presented numerical simulation model aims to adequately reproduce the resulting set of thermal characteristics of the modular elements, to determine with sufficient accuracy their distribution in the real objects, implemented inthe models in DSF systems. An algorithm is developed in the study and graphical visualization of three models of double facade systems with and without DSF are analysed under winter conditions, using data from a meteorological station located in North-Eastern Bulgaria. A software product was used to represent the processes of heat and mass transfer, in which the corresponding boundary and initial conditions were set, based on which the results and analyses were obtained. The use of such numerical modelling is effective enough to predict the expected thermal behaviour of DSF systems. Thus, when selecting a DSF facade system, awareness of the thermal behaviour is ensured, and the financial efficiency of the project is more easily determined. Such a customized approach not only improves the sustainability and efficiency of buildings, but also satisfies the unique preferences and requirements of the customers.

Prevalence of Diabetic Retinopathy Among Diabetic Patients from Northeastern Bulgaria.

Diabetic retinopathy (DR) is a leading cause of visual impairment globally among working-aged individuals. This study aims to update data on DR prevalence in Bulgaria. The present cross-sectional study was conducted between 1 January 2022 and 1 January 2023, using a local diabetes registry from the city of Varna as a sampling framework. In total, 587 diabetic patients underwent DR examination. Data included demographics, diabetes type/duration, treatment, and ophthalmic history. DR status was assessed using indirect slit-lamp biomicroscopy or digital fundus photography, graded by the International Clinical Diabetic Retinopathy Scale. Of 587 participants, 13 were excluded due to cataract-related ungradable images. The median age was 65 years (IQR 56-73), with a slight female predominance (54%). The overall prevalence of any DR was 39.9% (95% CI 35.9-44.0), with non-proliferative DR (NPDR) at 27.5%, proliferative DR (PDR) at 7.3%, and macular edema (DME) at 5%. Type 1 diabetes patients had significantly higher DR prevalence (68.8%) than type 2 (34.1%, p < 0.001). Men exhibited higher DR prevalence. Age and diabetes duration correlated positively with DR prevalence. Insulin treatment was associated with higher DR prevalence (55.6%) than oral antidiabetic treatment (22.5%, p < 0.001) for type 2 diabetes patients. Among those diagnosed with DR, 70.9% received treatment, mainly laser therapy. These findings provide epidemiological insights for future research and emphasize the need for a comprehensive national DR screening program in Bulgaria. Technological advancements enable proactive measures to mitigate DR-related visual impairment and blindness, including widespread screening, even in rural areas.

First record of Biscogniauxia mediterranea (De Not.) Kuntze on Quercus rubra L. in Bulgaria

The endophytic fungus Biscogniauxia mediterranea, a causal agent of charcoal canker disease, was established for the first time on red oak (Quercus rubra) in Bulgaria. Symptomatic trees were found in 2023-2024 in the field protective forest belts planted in the State Hunting Enterprise Balchik (Sokolovo and Trigortsi villages) and State Forest Enterprise Dobrich (Kozloduytsi Village) in northeastern Bulgaria. Water stress during the last growing seasons seems to reduce red oak trees’ resistance and predispose them to be infected with the pathogen B. mediterranea. The disease has caused dieback of infected trees and increased their vulnerability to attacks by xylophagous insect pests.

Retrospective epidemiological study of the width of maxillary diastema in patients from northeastern Bulgaria.

A maxillary diastema (MD) is identified when the gap between the central incisors exceeds 0.5 mm. It poses an a and phonetic concern, often seen in mixed dentition and occasionally continuing into permanent dentition.

Занаяти и занаятчийско развитие на християните в османския провинциален град (По примера на Ески Джума през първата половина на XIX век)

This article is a study of the types of crafts practiced, and their development according to Ottoman Turkish archival documents for the town of Eski Juma (today’s Targovishte, Northeastern Bulgaria). The data was compiled using the nufus, temettuat and jiziye registers from the first half of the 19th century. The data on the occupations of the urban population in the nufus and temettuat censuses of the 1830s and 1840s are presented in tabular form. This makes it easier to compare the craft industries of the different ethno-religious communities and gives readers the opportunity to familiarize themselves with all the crafts practiced in the Qazalian center of Eski Juma. The registers of the period constitute another valuable source for the development of the various professions among the Christian inhabitants of the town of Eski Juma in the first half of the 19th century.

Prehistoric salt production: Technological approach in ceramic studies

Numerous studies have been made on salt production in the European Iron Age, especially through broken low-fired clay artefacts known as “briquetage”. The vessels used in stoves are called salt moulds or salt containers. They serve both as crystallizer and mould for the salt obtained from concentrated brine. For the origin of salt production, archaeological evidences in Europe indicate that salt exploitation was intensified from the 5th millennium BC by using salt moulds in ceramic material. In this paper, we will present two studies conducted on “chaîne opératoire” of salt moulds making from two production sites, one in North-Eastern Bulgaria (Solnitstata, Provadia, c. 4700–4450 BCE), the other in West-Central France causewayed enclosures (c. 3400–2900 BCE). In both cases, the contexts in which these salt exploitations arose testify to an increase in social tensions.By focusing on the technical choices adopted in the manufacture and the use of these particular pots, we will see that for a same function several technical solutions are possible. However, we will attempt to define a general framework of technical choices and patterns observed in these pots which are often fragmented and rarely identified as salt moulds on archaeological sites except on production sites. This pottery is also excellent evidence for the development of specialised salt extraction throughout Europe since the late prehistoric period.

Damage caused by singing cicadas (Hemiptera: Cicadidae) in the field protective forest belts in South Dobrudzha, Bulgaria

During the period 2020-2023, strong damage caused by singing cicadas (Hemiptera: Cicadidae) were registered on ash trees (Fraxinus spp.) in the field protective forest belts (FPFBs) in South Dobrudzha, northeastern Bulgaria. Bioacoustic studies have shown that the sounds are of Cicada orni. Many exuvia of the species were also found on the trunks and branches of ash trees. On the upper shoots and petioles, numerous oviposition holes were observed, which lead to leaf fall and drying of branch tips. In different FPFBs, tree crown damage ranges from a moderate (25-60% defoliation) to a severe (over 60% defoliation) degree. The attacks were stronger on Fraxinus excelsior and F. americana compared to F. angustifolia. The cicadas affect both old trees and young ash saplings. In young plantations, other tree species (Sophora japonica, Gleditsia triacanthos) were also affected. Imaginal activity of Cicada orni was recorded in July and August, and the peak of egg hatching occurred from early August to mid-September. The high number of Cicada orni necessitates the development of measures to control the pest in the FPFBs.

Chemical composition and antioxidant activity of propolis, stored for more than 30 years

The propolis is a unique natural product that has been used by people in traditional medicine since ancient times. The aim of the present work is to determine the chemical composition and antioxidant activity of propolis, originating in 1993 from North-Eastern Bulgaria. The stored raw material has unchanged physical and chemical parameters - appearance, color, smell, content of mechanical impurities, wax content (19.6%), oxidizability index (16), active acidity (5.5), acid number (42.3 mg KOH/ g), ester number (152 mg KOH/g), boiling point (107°C). The data show that 40 components were identified, representing 99.14% of the total composition. The main components (over 2%) are: chrysin (18.37%), pinobanksin-3-etenoate (13.38%), pinobanksin-3-propanote (11.38%), pinobanksin-3-pentanoate (9.36%), squalene (6.36%), galangin (5.91%), dihydrochrysin (4.11%), pinobanksin-3-butenoate (2.94%), caffeic acid isomer 2 (2.74%), and (E)-sinapic acid (2.23%). Total phenols were 23.91 mg GAE/g. Antioxidant activity was determined by three methods: DPPH (1874.12 mMTE/g), FRAP (1039.18 mMTE/g), and ABTS (1539.52 mMTE/g). The antioxidant effect was monitored against goose fat and sunflower oil. The obtained data show maximally preserved physical parameters, chemical composition and antioxidant activity of the propolis sample stored for more than 30 years, which can be used in various products, an object of future research.

The Bessarabian (Sarmatian) reef buildup between the village of Tyulenovo and Cape Shabla (Northeastern Bulgaria) as climatic and paleoecological indicator

The Bessarabian (Sarmatian) limestones composed mainly of endemic foraminifera Nubicularia novorossica are studied in detail in three sections between the village of Tyulenovo and Cape Shabla (Northeastern Bulgaria). An important reef buildup found in the upper levels of the sections allows to reconstruct the climatic and paleoenvironmental conditions. The most prominent changes are а shift from subtropical to drier climate and increased wave activity. This led to a decrease in the amount of Nubicularia novorossica and an increase in encrusting organisms such as encrusting nubicularia, bryozoans and red algae, which protected the newly formed sediments from destruction by the strong wave disturbance. The occurrence of less favorable climatic conditions is also evidenced by the presence of microbial micrite masses in the reef limestones.

Archaeoseismological study in northeastern Bulgaria: Islands in Durankulak Lake

The most northeastern part of the territory of Bulgaria is characterized by high seismicity. In 2019, archeoseismological studies of traces of strong earthquakes were carried out in the oldest architectural monument in Europe – Durankulak. There are reports of earthquakes in these places in the Middle Ages and in Аntiquity, but the data on the location of their foci is unspecified. Therefore, a team of scientists from Bulgaria and Russia carried out special scientific research on the islands in Lake Durankulak. A large number of artifacts have been found on the Big Island. The ruins located there are very old and have fixed traces of seismic impacts that have occurred over a long period of time. As a result of paleoseismological and archaeoseismological studies, three major earthquakes have been identified. Most likely, the focus of the first is connected to the Intramysian fault, and the focus of the second and third to the Shabla-Kaliakra seismic zone. The first was between VIII and IX degree on the scale of MSK 64, the second between IX and X, the third also between VIII and IX degree on the same scale.

Malnutrition in Institutionalized and Non-Institutionalized Neurologically Impaired Children in Bulgaria

Introduction: The nutritional status of children with neurological impairment affects their health and quality of life. Bulgaria has many abandoned disabled children in residential homes. Lack of parental care puts them at risk for poor growth, suboptimal nutrition, and physical and mental development. Our study aims to identify factors associated with poor nutrition in Bulgarian children with neurological impairment living in different environments. Methods: From January to December 2017, a cross-sectional study was conducted in northeastern Bulgaria. We recruited 109 residential and nonresidential children. The study included demographics, medical history, anthropometric measurements, biochemical tests, nutritional assessment, and gastrointestinal signs and symptoms. Data were analyzed with Jamovi 2.2.5 at a 0.05 significance level. Logistic regression was used to predict wasting in both environmental settings. Results: About 70% of the neurologically impaired children living in residential settings have malnutrition based on weight-for-age Z-score, compared to 25% of the non-residential children. Prematurity, low gross motor function (as measured by the gross motor function classification system), pureed food consumption, birth before 37 weeks, and living in residential care homes are linked to poor nutrition. Conclusion: Neurologically impaired children have a poor nutritional state, especially those living in residential homes. The study underscores the pressing need for the allocation of additional nutrition resources to effectively address the nutritional and developmental needs of children with neurological disabilities in Bulgaria.

PREVALENCE OF CARIES AND THE NEED FOR URGENT DENTAL TREATMENT AMONG CHILDREN WITH NEUROLOGICAL IMPAIRMENT IN NORTHEASTERN BULGARIA

Introduction: Oral health is extremely important for the quality of life and well-being. Findings reveal that people with special needs have difficulties in getting dental care, which increases their risk of oral diseases. The recommendations for dental examination are identical for patients with and without neurological impairment. This study aimed to assess the prevalence of caries and overall dental health among children with motor and mental disabilities in Northeastern Bulgaria. Methods: A total of 53 children with neurological impairment under the age of 18 were selected from Varna and Ruse from April to October 2017. Data on age, gender, height, weight, caregiver education level were collected. Information on oral hygiene behavior and diet was gathered as well. The 2013 World Health Organization standards for dental caries were used to assess the oral health status. The data were analyzed with the statistical package Jamovi v.2.2.2.0. Results: Children were divided into two groups – with predominantly motor or mental impairment. Both groups had high rates of caries and need for urgent dental treatment with no significant difference observed. The CPITN correlated positively with motor impairment (Spearman's rho= 0.393; p= 0.043). It was discovered that children with motor impairment had a higher prevalence of malocclusion than children with mental impairment (rho= -0.331; p= 0.016). The number of caries correlated as well with the type of occlusion (Spearman's rho=0.378; p=0.005), the dentition type (rho=0.343; p=0.012) and the age (rho= 0.372; p= 0.006). Conclusion: The study findings indicate that both types of neurological impairments were associated with a high frequency of caries and a significant need for urgent dental care. More frequent dental examination is thought to improve oral health. Nevertheless, more studies are required to substantiate this theory.

Peripheral blood cell count ratios as a predictor of poor functional outcome in patients with acute ischemic stroke

ABSTRACT Background and aims Acute ischemic stroke (AIS) is a leading cause of death and long-term disability worldwide. Thromboinflammation plays an important role in the pathophysiology of stroke. The peripheral blood cell count ratios (PBCCR): neutrophil‐to‐lymphocyte ratio (NLR), platelet‐to‐lymphocyte ratio (PLR), and lymphocyte‐to‐monocyte ratio (LMR), are global inflammatory indicators with prognostic value for the clinical outcome after stroke. We aimed to determine the relationship between NLR, PLR, or LMR and the functional outcome three months post-stroke. Methods A prospective, hospital-based study, including 141 participants with AIS, was conducted at a referral stroke center in North-Eastern Bulgaria. The PBCCRs were obtained during the first 24 hours after stroke onset. Stroke severity was measured using the NIHSS scale, and functional outcome was assessed with the modified Rankin Scale (mRS) at discharge and 3 months post-stroke. Results We found significantly lower total lymphocyte counts, and higher NLR, PLR, and C-reactive protein in the poor-outcome group (mRS>3) three months post-stroke. A positive correlation was found between the NIHSS score and mRS score on discharge, NLR, and PLR with the worse outcome on the third month. The receiver operating characteristic (ROC) curves showed the predictability of NLR (AUC, 0.626, 95%CI: 0.524–0.724, p = 0.018), and for PLR– (AUC, 0.613, 95%CI: 0.510–0.716, p = 0.031). The optimal cutoff value for NLR was 2.68 (sensitivity 77.8% and specificity 60.4%), and for PLR - 122.6 (sensitivity 77.8% and specificity 61.5%). Conclusion Neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio are simple, widely available, and cost-effective biomarkers with high prognostic value for the clinical outcome three months post-stroke.

Prevalence and risk factors of burnout among community pharmacists in Northeast region of Bulgaria - a pilot study

Background: Burnout is described as an emotional, mental and physical exhaustion observed in healthy people and directly related to their professional context. The objective is to study the level of burnout among community pharmacists and to identify the workplace factors affecting it. Materials and methods: Using a questionnaire, specifically designed by the authors of the study, an anonymous survey was conducted in the region of Varna, as the largest region of Northeastern Bulgaria. The questionnaire contains questions about the demographic characteristics; a standardised burnout measure tool (MBI-HSS-MP), and questions regarding the specifics of the work environment. According to MBI-HSS-MP, burnout is associated with high levels of emotional exhaustion (EE) and depersonalisation (DP) and low level of personal accomplishment (PA). Results: The participants in the pilot study were 127 masters of pharmacy. Regarding individual factors, a statistically significant relationship was found between age and the scales emotional exhaustion EE (p = 0.012), depersonalisation DP (0.028) and personal accomplishment PA (p = 0.028). Most susceptible to ЕЕ (p = 0.014) and DP (p = 0.008) were the age group 25–45 years while most satisfied with their PA were in the age group 46–55 years (p = 0.016). From the organisational factors, the large number of patients had the greatest impact on burnout (DP р = 0.000 /ЕЕ р = 0.006). The other key factors for burnout were an insufficient number of pharmacy staff, a heavy administrative burden and a wide range of medicinal products. Conclusion: It is necessary to develop training courses for young professionals to introduce them gradually into the work process and build up skills for effectively coping with stress. Proposals need to be made for reducing the administrative burden of pharmacists and maintaining staffing levels that are adequate to the patient flow and expanding the capabilities of The Specialised Electronic System for Tracing and Analysis System of Medicinal Products (SETASMP).

Influence of geological and hydrogeological settings in assessing the stability of a landslide slope in the Tutrakan area, Northeastern Bulgaria

The study is focused on the assessment of the stability of the lower part of the right slope of the Danube River. The research area is situated in the town of Tutrakan, Northeastern Bulgaria. The present study investigates the likelihood of activating landslide processes due to construction works on the water supply and sewerage network of the town, as well as the influence of the natural geological and hydrogeological settings of the region. The research area is part of the Danubian Plain. The groundwater level lies between 7 and 26 m below the surface, in the sandy sediments and limestones of the Pliocene that form the semi-confined to unconfined aquifer. They are mainly formed by infiltration of precipitation through the loess layer. The groundwater discharge is carried out naturally and technogenically towards the Danube, through a herringbone system of drains built in the toe of the landslide cirques. The assessment of the slope stability was made for the different hypotheses – natural (momentous – including the existing buildings), constructional (including excavations), primary and specific (including seismic forces) combination of stresses. The different geodynamic models, taking into account the influence of groundwater, the influence of different destabilizing factors and seismic impact, show that the slope, as well as the studied sections of it – the landslide cirques, are in a stabilized state, with safety coefficients (Fs &gt; 1). According to the mechanism of deformation, the landslides are classified as a translational slide, and deep seated according to the depth of the slip zone. They are contemporary and currently active. The study confirms the hypothesis of the origin of the landslide masses in the area, formed as a mixture of loess material and Pliocene clays. The groundwater level is directly related to the current state of the landslide slope stability.

Preliminary observations on the food availability and diet composition of the Romanian hamster Mesocricetus newtoni (Rodentia, Cricetidae)

The Romanian hamster Mesocricetus newtoni is endemic to South-Eastern Romania (Dobruja region) and North-Eastern Bulgaria, and prefers steppic, arid, uncultivated habitats, but is also found in alfalfa fields, less often in corn cultures and field-protecting vegetation belts. Previous studies provide only limited data regarding the diet of this cryptic species. The diet of one family group (one female and four pups) was monitored for 10 days, during the vernal season. The data was collected using camera traps and direct observations, supplemented by photos. Plants were identified at the species level. A vegetation survey was performed in a radius of 25 m2 around the burrows using the pratological method, estimating a percentage of each plant species present in the habitat. A number of 16 plants were identified as part of the diet of the Romanian hamster, mostly herbaceous species within the Brassicaceae family. According to the observations, Erodium cicutarium (Geraniaceae) and Papaver rhoeas (Papaveraceae) were consumed most frequently, followed by Descurainia sophia (Brassicaceae), Sisymbrium orientale (Brassicaceae), Medicago minima (Fabaceae) and Buglossoides arvense (Boraginaceae). In the studied area,&amp;nbsp;38 plant taxa were determined and characterized as ruderal and segetal (weeds of arable land) plants, mostly native to Eurasia. The purpose of this study is to provide novel data on the diet composition of the Romanian hamster in accordance with plant taxa availability and to emphasize the importance of conservation measures of its preferred habitats, which are crucial to the survival of the species.

Novel in-situ observations on the diel surface activity of the Romanian hamster, Mesocricetus newtoni (Rodentia, Cricetidae), during pup rearing

The Romanian hamster Mesocricetus newtoni is a threatened and cryptic species, with a distribution limited to North-eastern Bulgaria and South-eastern Romania (Dobruja region). Current literature does not provide sufficient data regarding diel activities and behavior of this species, especially under field conditions. In this context, one female M. newtoni, during the rearing period of her four pups, was monitored for ten days using camera traps. For each documented activity, the date, time, age of the individual, type of activity, and duration were recorded. In total, from the 26140 media files, 72968 seconds were recorded as active behaviors. Data analysis revealed that diurnal activity was predominant and documented for all monitored days; however, the animals spent more time per each activity during the night. The nocturnal activity was present but erratic, without significant patterns. No significant differences were observed in the median duration of activities of the adult compared to the immature individuals. Both the adult female and pups spent time exploring the burrow entrance, especially during the day, but immatures were more reserved to leave the burrow than the female. The female used four burrows for rearing the pups. During this time, food storage behaviors and transferring of immatures between burrows, as well as the weaning of the pups were documented. This study demonstrates that M. newtoni exhibits significant diurnal activity, at least in certain ecological and physiological conditions.

Phytosanitary Status of Wheat Crops in Northeastern Bulgaria

Phytosanitary Status of Wheat Crops in Northeastern Bulgaria

Investigation of polychlorinated biphenyls in breast milk from two regions in Bulgaria.

Human breast milk is an optimally balanced infant food and a suitable tool for assessing the burden of humans with lipophilic persistent organic pollutants. The aim of this study was to investigate the accumulation profile of polychlorinated biphenyls in breast milk of women living in Bulgaria and to assess the health risk to infants. Breast milk samples were obtained from 72 healthy primiparae and multiparae mothers, living in two regions in northeastern Bulgaria - Varna region and Dobrich region, in the period October 2019-July 2021. Important information for the study, such as age, body mass, smoking and dietary habits, was collected through a questionnaire. Fifteen congeners of PCBs, including six indicator congeners, were determined by capillary gas chromatography system with mass spectrometry detection. The lipid content of the tested samples was in the range from 0.5% to 6.7%, with average value 3.25%. The six indicator PCBs in human milk samples formed up to 89% of the total PCBs levels. The most abundant congener was PCB 153, followed by PCB 138 and PCB 180. Five of the 15 PCB congeners (77, 126, 128, 156, 169) were not detected in any of the milk samples. The arithmetic mean PCB levels in milk samples from Varna (32.7ng/g lw) were found higher than PCB levels in breast milk of mothers from Dobrich (22.5ng/g lw). The highest PCB levels were found in milk samples from primiparae mothers in 36-40 age group (for both regions). Infant exposure to PCBs present in human milk was estimated using toxic equivalents (TEQ). The health risk to infants was assessed and was compared to the tolerable daily intake (TDI). Positive correlation was found between the arithmetic mean PCBs levels and two important factors - the age and body mass index of the primiparae group. The mean values of the analyzed PCB congeners in breast milk samples from multiparae were lower than in those from primiparae mothers. The regional differences in PCB concentrations were small, suggesting similar exposures in the studied regions. The levels of PCBs in breast milk were found lower than levels from studies in other European countries. Statistical data does not show any association between PCB levels in milk and dietary habits. The results showed that infants are not at risk of any adverse effects caused by PCBs through breast milk.

What's Down the Hole? Archaeobotanical evidence on plant subsistence and vegetation during the Hellenistic period at an archaeological site near Voditza village, north-eastern Bulgaria

The archaeological site 5012-West in the territory of the village of Voditza, Targovishte Region, north-eastern Bulgaria, is interesting because of its features and wide chronological range. From an area of 7000m², a total of 116 structures from various chronological periods have been excavated. However, pits from the Hellenistic Period (late 3rd to early 1st century BC) are most numerous and provide invaluable archaeobotanical evidence on plant subsistence and local vegetation. The archaeobotanical remains have been recovered from flotation samples, collected from pitfills. The archaeobotanical assemblage comprises carbonised remains from several annual cereal crops – hulled and free-threshing wheats, naked barley (Hordeum vulgare var. nudum L.), millet (Panicum miliaceum L.), oat (Avena sativa L.) and chaff. The weedy flora is represented by annual ruderal and synanthrophic species such as goosefoot (Chenopodium album L.), bedstraw (Galium aparine L.), knotgrass (Polygonum aviculare L.), and wild mustard (Sinapis arvensis L.). Based on the discovered plant remains, we can only propose a partial reconstruction of the agricultural practices and local vegetation cover. However, the collection of samples from specific contexts – storage facilities and pits, provided an opportunity to observe the 'secondary environment' of the utilised plant resources and to identify possible depositional processes. Thus, taphonomic and contextual analyses gave us important insights into the behavioural factors that affected the composition of the archaeobotanical assemblage.