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The conscious need of transition to an environmentally friendly way of society life on a global scale in recent years outlines a new direction in the development and activity of humanity. A number of documents at the global and European levels are a clear sign of countries' determination t change significantly their attitude to the natural resources use in order to limit climate change and global warming of the planet, to ensure an environmentally friendly way of life and activity and the long-term preservation and well-being of human civilization. Small and medium-sized businesses in Bulgaria are a huge potential resource that can be a powerful engine for realizing the ecological transformation of the country's economy. Current progress, financial ability and access to financial resources as well as the outlooks of small and medium companies in Bulgaria in the green transition are analyzed in this study. SMEs are classified in 3 clusters in terms of their progress in the transition process using TwoStep Cluster analysis with a set of indicators identified by authors. It has been established that despite the existing difficulties and the great inertia in the process of transition to an ecological economy of small and medium-sized companies in particular, more or less sustainable steps leading to the reduction of carbon emissions are observed, in the production of cleaner energy as well as elements of circularity in production processes and consumption. The transition appears to be taking place more quickly in medium-sized companies operating in manufacturing, logistics and transport, while small, mostly family-owned, companies with businesses in retail or service are progressing more slowly in this process. All the companies need of more serious and adequate support in the way of ecologization both by state regulations that to be applied clearly and transparently and by adequate financing. [ABSTRACT FROM AUTHOR]

During the period 2018-2020 in the experimental field of the Agricultural Institute, Shumen, on calcic chernozem soil type, a field experiment with triticale (x Triticosecale Wittmack) was conducted. The experiment was based on the block method, in four replications with a size of the experimental plot of 10 m2. Sowing was carried out in October with a sowing rate of 500 germinate able seeds/m2 after the predecessor sugar beet (Beta vulgaris L.). In the appropriate periods treatments were made in 4 variants: 1) Control-untreated variant. 2) Treatment with biodynamic preparations: Preparation 500 (5% solution) + Fladen preparation (1.5% solution) + preparation 501 (1.5 g for 300 l H2O/ha). 3) Treatment with biological preparations: Heliosulfur (500 ml/ha) + Free N (500 ml/ha). 4) Combined treatment with the same biodynamic and biological preparations. The following indicators were studied: plant height, number of spikelet's per spike, number of grains per spike, grain weight per spike. After the statistical analysis for the first year of the study, a proven positive difference was found in all indicators in the combined biodynamic + biological method of cultivation, as well as in the stand-alone biological. In the second year of the study, a proven positive difference was obtained in all studied indicators in the variants treated with biodynamic preparations and the combination of biodynamic + biological preparations, with statistical significance for p<0.001. A positive correlation was found between all variants of the observed indicators at p<0.05. [ABSTRACT FROM AUTHOR]

Determining the productive potential of flowering vegetation is crucial in obtaining bee products. The application of a remote sensing approach of terrestrial objects can provide accurate information for the preparation of maps of the potential bee pasture in a given region. The study is aimed at the creation of a novel algorithm to identify and distinguish white flowering honey plants, such as black locust (Robinia pseudo-acacia) and to determine the areas occupied by this forest species in mixed forest ecosystems using UAV-based RGB imaging. In our study, to determine the plant cover of black locust in mixed forest ecosystems we used a DJI (Da-Jiang Innovations, Shenzhen, China) Phantom 4 Multispectral drone with 6 multispectral cameras with 1600 × 1300 image resolution. The monitoring was conducted in the May 2023 growing season in the village of Yuper, Northeast Bulgaria. The geographical location of the experimental region is 43°32′4.02″ N and 25°45′14.10″ E at an altitude of 223 m. The UAV was used to make RGB and multispectral images of the investigated forest massifs, which were thereafter analyzed with the software product QGIS 3.0. The spectral images of the observed plants were evaluated using the newly created criteria for distinguishing white from non-white colors. The results obtained for the scanned area showed that approximately 14–15% of the area is categorized as white-flowered trees, and the remaining 86–85%—as non-white-flowered. The comparison of the developed algorithm with the Enhanced Bloom Index (EBI) approach and with supervised Support Vector Machine (SVM) classification showed that the suggested criterion is easy to understand for users with little technical experience, very accurate in identifying white blooming trees, and reduces the number of false positives and false negatives. The proposed approach of detecting and mapping the areas occupied by white flowering honey plants, such as black locust (Robinia pseudo-acacia) in mixed forest ecosystems is of great importance for beekeepers in determining the productive potential of the region and choosing a place for an apiary. [ABSTRACT FROM AUTHOR]

Natural products (NPs) have played a significant role in modern drug discovery, serving as a source of inspiration and ideas for drug design. NPs have led to advancements in the treatment of various diseases, including infectious, cardiovascular, cancer, and multiple sclerosis. Pharmaceutical companies are shifting towards biotechnological methods to develop medicines for complex diseases. NPs offer a wider chemical space compared to synthetic compounds, with unique structural features and a diverse range of bioactive compounds. In the context of kidney disease treatment, both NPs and synthetic drugs have made significant contributions to pharmacotherapy. NPs have the potential to provide unique structural motifs for future drug development. [Extracted from the article]

Several models on honeybee population dynamics have been considered in the past decades, which explain that the growth of bee colonies is highly dependent on the availability of food and social inhibition. The phenomenon of the Colony Collapse Disorder (CCD) and its exact causes remain unclear and here we are interested on the factor of social immunity. We work with the mathematical model in [1]. The core model, consisting of four nonlinear ordinary differential equations with unknown functions: brood and nurses B, iB, N and iN represent the number of healthy brood, infected brood, healthy nurses, and infected nurses, respectively. First, this model implements social segregation. Highrisk individuals such as foragers are limited to contact only nectar-receivers, but not other vulnerable individuals (nurses and brood) inside the nest. Secondly, it includes the hygienic behavior, by which healthy nurses actively remove infected workers and brood from the colony. We aim to study the dynamics and the long-term behavior of the proposed model, as well as to discuss the effects of crucial parameters associated with the model. In the first stage, we study the model equilibria stability in dependence of the reproduction number. In the second stage, we investigate the inverse problem of parameters identification in the model based on finite number time measurements of the population size. The conjugate gradient method with explicit Frechet derivative of the cost functional is proposed for the numerical solution of the inverse problem. Computational results with synthetic and realistic data are performed and discussed. [ABSTRACT FROM AUTHOR]