Showing papers by "Sofia University published in 2022"

Environmental factors influencing the transmission of the coronavirus 2019: a review

Abstract: The coronavirus 2019 pandemic, induced by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has strongly altered healthcare systems and the economy worldwide. The lack of knowledge on this virus has led to the implementation of uncertain strategies and measures to fight the pandemic. Here, we review environmental factors that control viral transmission, such as air, temperature, humidity, food, water and sewage, insects, inanimate surfaces, hand hygiene, and social distancing. The main route of viral transmission is the respiratory tract through aerosols. Masks and social distancing are effective in ceasing air transmission. Proper cleaning of surfaces and hand disinfection are required, especially in healthcare units. Food should be handled properly, and food handlers should work based on hygienic protocols. Water and sewage transmission, and transmission through insects appear less important than other environmental factors.

Approaches to cost-effectiveness of payments for tree planting and forest management for water quality services

Abstract: The evaluation of the cost-effectiveness of Payments for ecosystem services (PES) in fostering positive environmental outcomes has been central to the scientific debate on their implementation. PES cost-effectiveness can be affected by a myriad of environmental, institutional and socio-economic factors operating at different spatial and temporal scales. Moreover, it can be affected by synergies and trade-offs in the provision of ecosystem services (ES). Planting trees is increasingly considered an effective measure to provide water-related ES. It can enhance watershed services such as nutrient retention, erosion control, stream flow regulation, protection against extreme events (e.g., floods and landslides), and lead to a permanent change in land use, replacing agricultural activities that give rise to diffuse pollution. Very few studies currently exist on the cost-effectiveness of tree planting for water quality benefits PES schemes in Europe. Including both review and research elements, this paper highlights challenges in undertaking such assessments. It develops a conceptual framework to help underpin future studies, with its application to three case studies in Denmark explored. Particular attention is given to the estimation of environmental effectiveness in the provision of water quality services and the importance of co-benefits. In the case where we exclude co-benefits from the analysis, the financial cost-effectiveness is always above zero, with central estimates (without discounting environmental improvements) of €10/Kg N, and €0.36 to €0.50/mg pesticide. Once co-benefits are accounted for, however, the social cost-effectiveness is negative (except for under the low estimates) as the value of the co-benefits exceeds the costs, with central estimates of -€28/Kg N, and -€0.34 to -€0.23/mg pesticide. The paper discusses the implications and lessons for PES cost-effectiveness analysis, and identifies research gaps. Increased knowledge of forest water benefits and the cost-effectiveness of woodlands for water schemes would help underpin future incentives to enhance the provision of these ES.

Integration culture of global banks and the transmission of lending shocks

Abstract: We document that a centralization decision-making culture of global banks affects the transmission of shocks from parent banks to their subsidiaries. Using a novel measure of integration culture of multinational banking conglomerates based on the prevalence of a language of power and authority in financial reports, we find that subsidiaries of banks with a relatively more autocratic integration culture cut lending significantly more after solvency shocks to the parent company. Our result is robust to instrumenting integration culture with political and economic factors of the parent bank’s home country.

GNSS Storm Nowcasting Demonstrator for Bulgaria

Abstract: 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.

Aeroterrestrial and Extremophilic Microalgae as Promising Sources for Lipids and Lipid Nanoparticles in Dermal Cosmetics

Abstract: Microscopic prokaryotic and eukaryotic algae (microalgae), which can be effectively grown in mass cultures, are gaining increasing interest in cosmetics. Up to now, the main attention was on aquatic algae, while species from aeroterrestrial and extreme environments remained underestimated. In these habitats, algae accumulate high amounts of some chemical substances or develop specific compounds, which cause them to thrive in inimical conditions. Among such biologically active molecules is a large family of lipids, which are significant constituents in living organisms and valuable ingredients in cosmetic formulations. Therefore, natural sources of lipids are increasingly in demand in the modern cosmetic industry and its innovative technologies. Among novelties in skin care products is the use of lipid nanoparticles as carriers of dermatologically active ingredients, which enhance their penetration and release in the skin strata. This review is an attempt to comprehensively cover the available literature on the high-value lipids from microalgae, which inhabit aeroterrestrial and extreme habitats (AEM). Data on different compounds of 87 species, subspecies and varieties from 53 genera (represented by more than 141 strains) from five phyla are provided and, despite some gaps in the current knowledge, demonstrate the promising potential of AEM as sources of valuable lipids for novel skin care products.

Characteristics of 2.45 GHz Surface-Wave-Sustained Argon Discharge for Bio-Medical Applications

Abstract: Cold atmospheric plasma (CAP) applications in various fields, such as biology, medicine and agriculture, have significantly grown during recent years. Many new types of plasma sources operating at atmospheric pressure in open air were developed. In order to use such plasmas for the treatment of biological systems, plasma properties should fulfil strong requirements. One of the most important is the prevention from heating damage. That is why in many cases, the post-discharge region is used for treatment, but the short living particles in the active discharge zone and reactions with them are missed in that case. We use the active region of surface-wave-sustained argon plasma for biological systems treatment. The previous investigations showed good bactericidal, virucidal, seeds germination and decontamination effects at a short treatment time, but the discharge conditions for bio-medical applications need specific adjustment. A detailed theoretical and experimental investigation of the plasma characteristics and their possible optimization in order to meet the requirements for bio-medical applications are presented in this paper. The length of the plasma torch, the temperature at the treatment sample position and the microwave radiation there are estimated and optimized by the appropriate choice of discharge tube size, argon flow rate and microwave power.

A Neighborhood Framework for Resource-Lean Content Flagging

Abstract: Abstract We propose a novel framework for cross- lingual content flagging with limited target- language data, which significantly outperforms prior work in terms of predictive performance. The framework is based on a nearest-neighbor architecture. It is a modern instantiation of the vanilla k-nearest neighbor model, as we use Transformer representations in all its components. Our framework can adapt to new source- language instances, without the need to be retrained from scratch. Unlike prior work on neighborhood-based approaches, we encode the neighborhood information based on query– neighbor interactions. We propose two encoding schemes and we show their effectiveness using both qualitative and quantitative analysis. Our evaluation results on eight languages from two different datasets for abusive language detection show sizable improvements of up to 9.5 F1 points absolute (for Italian) over strong baselines. On average, we achieve 3.6 absolute F1 points of improvement for the three languages in the Jigsaw Multilingual dataset and 2.14 points for the WUL dataset.

Assessment of existing BIM implementation processes of a public organization to improve building assets management and maintenance

Abstract: Abstract In the lifecycle of a building, the longest phase is generally that of operation and maintenance (O&M). The data needed to support O&M is mainly generated during the design, construction, and commissioning of the built asset phases. However, the extraction and transfer of relevant O&M data from the project documents remain a major issue in that it is time consuming and error prone. Nowadays, Building Information Modeling (BIM) allows different project team members to collaborate and share building data in real time. However, as-built models handed-over to the asset management team are quite voluminous and usually lack the necessary information for the O&M phase. This is due to an absence of O&M information requirements specification, and the lack of compliance monitoring and control during the project. This paper presents an action research focused on the issues encountered by a public building owner to manage their BIM processes. It demonstrates issues of BIM readiness and capabilities, both at the project and O&M levels, by mapping the gaps in the existing processes. Building owners rely on the design professionals’ expertise to guide them but do not have the adequate resources, knowledge, and tools to ensure the quality of the models delivered regarding O&M requirements. Major issues in the management of information for O&M were identified, and some recommendations are proposed.

The <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si18.svg"><mml:mrow><mml:msup><mml:mi>a</mml:mi><mml:mn>3</mml:mn></mml:msup><mml:msup><mml:mstyle mathvariant="normal"><mml:mi>Σ</mml:mi></mml:mstyle><mml:mo>+</mml:mo></mml:msup></mml:mrow></mml:math> state of KCs revisited: Hyperfine structure analysis and potential refinement

Abstract: Laser-induced fluorescence spectra of the c3Σ+(vc,Jc=Nc)→a3Σ+(va,Na=Jc±1) transitions excited from the ground X1Σ+ state of 39K133Cs molecule were recorded with Fourier-transform spectrometer IFS125-HR (Bruker) at the highest achievable spectral resolution of 0.0063 cm−1. Systematic study of the hyperfine structure (HFS) of the a3Σ+ state for levels with va∈[0,27] and Na∈[24,90] shows that the splitting monotonically increases with va. The spectroscopic study was supported by ab initio calculations of the magnetic hyperfine interaction in X1Σ+ and a3Σ+ states. The discovered variation of the electronic matrix elements with the internuclear distance R is in a good agreement with the observed va-dependencies of the HFS. Overall set of available experimental data on the a3Σ+ state was used to improve the potential energy curve particularly near a bottom, providing the refined dissociation energy De=267.21(1) cm−1. The ab initio HFS matrix elements, combined with the empirical X1Σ+ and a3Σ+ PECs in the framework of the invented coupled-channel deperturbation model, reproduce the experimental term values of both ground states within 0.003 cm−1 accuracy up to their common dissociation limit.

Purposely Development of the Adaptive Potential of Activated Sludge from Municipal Wastewater Treatment Plant Focused on the Treatment of Landfill Leachate

Abstract: Biological treatment is a key technology in landfill leachate treatment However, often its efficiency is not high enough due to the pollutants in concentrations above the critical ones. The present study aimed to investigate the adaptive responses that occur in activated sludge (AS) during landfill leachate purification. A model process with AS from a municipal wastewater treatment plant and landfill leachate in increasing concentrations was constructed. The data showed that when dilutions 25 and 50 times had been applied the structure of the AS was preserved, but the COD cannot be reduced below 209 mg O2/L. The feed of undiluted leachate destroyed the AS structure as SVI was reduced to 1 mL/g, biotic index to 1, floc size was greatly reduced and COD remained high (2526 mg O2/L). The dominant group of protozoa was changed from attached to free-swimming ciliates. An increase of the bacterial groups responsible for the xenobiotics elimination (aerobic heterotrophs, genera Pseudomonas, Acinetobacter, Azoarcus, Thauera, Alcaligenes) was registered. This was accompanied by a significant increase in free bacteria. The obtained data showed that for optimal treatment of this type of water it is necessary to include a combination of biological treatment with another non-biological method (membrane filtration, reverse osmosis, etc.).

Pollen and Chemical Content of Beebreads from Serpentine Areas in Albania and Bulgaria

Abstract: Beebread from serpentine localities in Albania and Bulgaria were characterized based on their pollen and chemical element content (macroelements K, Ca, Mg, P and microelements Cd, Co, Cr, Cu, Fe, Mn, Na, Ni, Pb, Zn) aiming to (1) evaluate the effect of serpentine soil on the quality of beebread; (2) compare elemental concentrations in samples from serpentine areas in Albania and Bulgaria; and (3) compare the differences in pollen spectra. Chemical element content was determined using microwave digestion of beebread samples followed by ICP-OES measurements. The analytical procedure developed was validated by added/found method. Analytical figures of merit of analytical method proposed were presented. The melissopalynological analysis was applied for pollen characterization. The results demonstrate clear difference in the pollen spectra between the two sets of samples, confirming differences in local serpentine flora in both countries, but specific pollen type is difficult to be suggested. The pollen content is related to the flowering period, climatic conditions, and bees forage preferences. The samples vary in their elemental concentrations depending on the pollen type and year of collection. The highest average concentrations found for K, Ca, Mg, and P are close to values reported in the literature. However, elevated concentrations observed for Ni, Cr, Mn, and Fe in beebread, especially from Albania, are in line with the serpentine characteristics of studied areas. The concentrations of Cd and Pb for all beebread samples are below permissible limits. The results should be taken into consideration in future specific food safety regulations at national and international level.

Acylpyrazolones possessing a heterocyclic moiety in the acyl fragment: intramolecular<i>vs.</i>intermolecular zwitterionic structures

Abstract: A series of acylpyrazolones possessing a methylene bridged heterocyclic unit in the acyl fragment are synthesized and characterized in solution and the solid state.

Cognitive Impairment and Dementia Data Modelling

Abstract: Recently, a lot of data with variety factors and indicators of cognitive diseases is available for clinical research. Although the transformation of information to particular data model is straight-forward, a lot of challenges arise if data from different repositories is integrated. Since each data source keeps entities with different names and relationships at different levels of granularity, the information can be partially lost or not properly presented. It is therefore important to have a common data model that provides a unified description of different factors and indicators related to cognitive diseases. This paper proposes a hierarchical data model of patients with cognitive disorders, which keeps the semantics of the data in a human-readable format and accelerates the interoperability of clinical datasets. It defines data entities, their attributes and relationships related to diagnosis and treatment. The data model covers four main aspects of the patient’s profile, including personal profile, anamnestic profile, related to social status, everyday habits, and head trauma history, clinical profile, describing medical investigations and assessments, comorbidities and the most likely diagnose, and treatment profile with prescribed medications. It provides a native vocabulary, improving data availability, saving efforts, accelerating clinical data interoperability, and standardizing data to minimize risk of rework and misunderstandings. The data model enables the application of machine learning algorithms by helping scientists to understand the semantics of information through a holistic view of patient. It is intended to be used by researchers in the field of Biostatistics, Bioinformatics, Neuroscience, etc. supporting them in content mapping and data integration from different datasets.

Institutions as Designers of Better Social Games

Abstract: Institutions predefine and make possible development of many social processes. As already discussed, institutions define “the rules of the game,” encouraging further social and organizational transformations. The aim of Chapter 6 is to propose an alternative approach for shaping the future institutions. By assuming institutions to be game-designers of complex social systems, there are explored the main mechanisms and elements of the game-design. Following this approach, the author discusses how institutions can transform to designers of new types of rules and social arrangements that will be more just and efficient for all. The structure of the chapter is as follows: In the first part there are identified the main elements of the game design, including game-mechanics, game-play, and game-word. The second part makes analysis of social ecosystems, where the new types of rules and regulations can stimulate creativity and innovations. Finally, an analysis is made about how institutions can figure out the gamification models and transform in order to promote new type of development and social cohesion. In this respect, Chapter 6 aims to propose an experiment of thought, discussing how to design more efficient and more socially just rules and regulations that can further ensure our sustainable development.

What theory for the new protest movements?

Abstract: This chapter aims to study the political and philosophical theories that pay special attention to the recent protest movements of the public space and try to think them in a more global and unified perspective. The authors who are in the focus of the analysis are Chantal Mouffe, Slavoj Žižek and Judith Butler. The main research interest is, on the one hand, to what extent these theories could really help us to understand the protest movements and, on the other hand, to what extent the protest movements could constitute an occasion for the contemporary political and philosophical theories to reinvent themselves. Thus, the main distinction should be drawn between the theories that have a rather instrumental approach to the protests, incorporating them into their pregiven conceptual framework, and the theories that can be provoked and influenced by what they consider original and valuable in the new protest movements of the public space.