Daugavpils University
  • Daugavpils, Latvia
Recent publications
In cows embryo transfer occurs on the 7 th day of the oestrous cycle. Embryo survival and successful pregnancy depend on many factors, including early interaction between embryo and endometrium. Therefore, the aim of our research was to describe histo-morphological characteristics of endometrium in donor and recipient cows on obtaining and transfer day, respectively (7 th day of the oestrus cycle). In addition, progesterone and oestradiol levels, the ipsilateral and contralateral corpus luteum, animal age, lactation number and days postpartum were determined. The results of the study revealed a significant difference in endometrial gland cell size, vacuolisation of glandular epithelium cytoplasm, and stromal oedema in the donor and recipient cows. However, these parameters were related only to the level of progesterone in the blood, and no other investigated factors in this study.
The question of targeted control over trajectories of systems of differential equations encountered in the theory of genetic and neural networks is considered. Examples are given of transferring trajectories corresponding to network states from the basin of attraction of one attractor to the basin of attraction of the target attractor. This article considers a system of ordinary differential equations that arises in the theory of gene networks. Each trajectory describes the current and future states of the network. The question of the possibility of reorienting a given trajectory from the initial state to the assigned attractor is considered. This implies an only partial control of the network. The difficulty lies in the selection of parameters, the change of which leads to the goal. Similar problems arise when modeling the response of the body’s gene networks to serious diseases (e.g., leukemia). Solving such problems is the first step in the process of applying mathematical methods in medicine and pharmacology.
Climate change affects timing of reproduction in many bird species, but few studies have investigated its influence on annual reproductive output. Here, we assess changes in the annual production of young by female breeders in 201 populations of 104 bird species (N = 745,962 clutches) covering all continents between 1970 and 2019. Overall, average offspring production has declined in recent decades, but considerable differences were found among species and populations. A total of 56.7% of populations showed a declining trend in offspring production (significant in 17.4%), whereas 43.3% exhibited an increase (significant in 10.4%). The results show that climatic changes affect offspring production through compounded effects on ecological and life history traits of species. Migratory and larger-bodied species experienced reduced offspring production with increasing temperatures during the chick-rearing period, whereas smaller-bodied, sedentary species tended to produce more offspring. Likewise, multi-brooded species showed increased breeding success with increasing temperatures, whereas rising temperatures were unrelated to reproductive success in single-brooded species. Our study suggests that rapid declines in size of bird populations reported by many studies from different parts of the world are driven only to a small degree by changes in the production of young.
This article aims to shed new light on young people’s participation in non-formal associations aimed at safeguarding traditions and national culture. Focusing on two case studies from Latvia within the international project CHIEF (Cultural Heritage and Identities of Europe’s Future), the study provides an in-depth analysis of how ‘culture’ is understood, practiced, and transmitted in non-formal education settings. The article also discusses what motivates young people in Latvia to get involved in associations aiming to preserve cultural heritage, and how these activities are connected to identity and attitudes toward other cultures.
Based on a single specimen from Eocene Baltic amber, Donacia (Protodonacia) bienkowskii subgen. et sp. nov. is described and illustrated. The new species is studied and illustrated in detail using X-ray microcomputed tomography (μCT). It is the first described species of Donaciinae (Coleoptera: Chrysomelidae) from Baltic amber and from fossil resin in general. Ecological groups of beetles that have been associated with aquatic habitats in the Baltic amber forest communities are briefly discussed. The studied specimen represents the first known member of the ecological group ‘phytophilous water beetles’ in this assemblage.
Animals adjust their use of alarm calls depending on social environments. We tested whether dominant (adult) and subordinate (juvenile non-kin) male crested tits ( Lophophanes cristatus ) warn each other and heterospecific willow tits ( Poecile montanus ) across the wintering season. Birds rarely alarm called when feeding alone. Both adult and juvenile crested tits warned each other in early winter, and adults did so in the middle of wintering season. However, juvenile males rarely warned conspecific adult males in the middle of the winter. Both adult and juvenile males stopped giving alarm calls when feeding together at the end of wintering season. The results suggest that the mid-winter reduction of juvenile alarms could increase the likelihood of successful predator attacks on adults, increasing the chances for juveniles to replace adults and acquire their territories. By contrast, both adult and juvenile males produced alarm calls throughout the season when foraging together with willow tits. Whether juvenile male crested tits could be selectively altering alarm call propensity to endanger adult males, thereby selfishly enhancing their own succession to territory ownership, is discussed. The results add to the understanding of the origin of mixed-species groups and explain the dynamics of social communication. This article is part of the theme issue ‘Mixed-species groups and aggregations: shaping ecological and behavioural patterns and processes’.
Hydrogen peroxide is present naturally in any living cell. Although hydrogen peroxide concentration in cell is strictly regulated during normal metabolism, several human diseases lead to increased hydrogen peroxide concentration in body fluids. It is beneficial to monitor hydrogen peroxide levels in human body for early disease diagnostics. This can be done by creation of electronic device, which will use electrochemical sensor in order to perform automated hydrogen peroxide concentration measurement in a sample. The aim of the research is to use printed circuit board (PCB) technology in order to create a replaceable electrochemical hydrogen peroxide sensor that could be cheaply mass-produced to enable further development of automated health diagnostics device.
Noteworthy new records of 12 species of mosses and liverworts, with notes on their taxonomy, distribution and ecology
Linear stability analysis of a combined convective flow in an annulus is performed in the paper. The base flow is generated by two factors: (a) different constant wall temperatures and (b) heat release as a result of a chemical reaction that takes place in the fluid. The nonlinear boundary value problem for the distribution of the base flow temperature is analyzed using bifurcation analysis. The linear stability problem is solved numerically using a collocation method. Two separate cases are considered: Case 1 (non-zero different constant wall temperatures) and Case 2 (zero wall temperatures). Numerical calculations show that the development of instability is different for Cases 1 and 2. Multiple minima on the marginal stability curves are found for Case 1 as the Prandtl number increases. Concurrence between local minima leads to the selection of the global minimum in such a way that a finite jump in the value of the wave number is observed for some values of the Prandtl number. All marginal stability curves for Case 2 have one minimum in the range of the Prandtl numbers considered. The corresponding critical values of the Grashof number decrease monotonically as the Prandtl number grows.
The concept of a smart city is widely implemented all over the world, and this fact creates both possibilities and new challenges for all participants and stakeholders of the process. This study examines the implementation of smart governance in the context of smart cities. The goal of the research is to distinguish between the effects and externalities of the smart governance domain, both positive and negative ones; the effects and externalities are elicited from the outcomes of smart governance implementation revealed from a review of scientific publications devoted to the results, barriers, and facilitators of smart governance functioning. The publications were selected according to a systematic review methodology, then the selected articles were analyzed and the factors that foster the processes of smart governance implementation (facilitators) or vice versa hamper the acquisition of results (barriers), as well as the outcomes of smart governance, were extracted. The extracted factors were attributed to six areas: Information, Efficiency, Citizen-Centricity, Transparency, Digital Divide, and Regulation. Further, the outcomes of smart governance implementation were distinguished as effects and externalities, which were both positive and negative.
This study details the quality of preservation of amber deposits in the Eocene. Through Baltic amber crack-out studies using Synchrotron Micro-Computed Tomography and Scanning Electron Microscopy it was found that the cuticle of a specimen of leaf beetle (Crepidodera tertiotertiaria (Alticini: Galerucinae: Chrysomelidae)) is exceptionally well preserved. Spectroscopic analysis using Synchrotron Fourier Transform Infrared Spectroscopy suggests presence of degraded α\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\upalpha$$\end{document}-chitin in multiple areas of the cuticle, and Energy Dispersive Spectroscopy supports the presence of organic preservation. This remarkable preservation is likely the result of several factors such as the favourable antimicrobial and physical shielding properties of Baltic amber as compared to other depositional media, coupled to rapid dehydration of the beetle early in its taphonomic process. We provide evidence that crack-out studies of amber inclusions, although inherently destructive of fossils, are an underutilised method for probing exceptional preservation in deep time.
Spirituality is a broad and multidimensional concept, while spiritual intelligence (SI) is an important prerequisite for the psychological health and social functioning of the individual. This article theoretically frames a psycho-pedagogical intervention (PPI) program for the development of SI in primary school students (age 7–10) in Latvia, describing the conceptual and procedural principles of the program. According to the literature, PPI is considered the most efficient form of instruction that, integrated into the learning process, may facilitate the rapid development of children in various fields. The article introduces the concept of SI and substantiates the theoretical model of SI in children. It discusses the types and functions of intervention programs; the main conditions for elaborating PPI; and reflects on the content, structure, and methods of a program applied to develop SI. The procedural dimensions of the PPI and the preparation of teachers to implement a given program are described. It is hoped that this study and its continuation may inspire the integration of the PPI into educational systems in other countries.
Relevance of the issue: the topicality of the issue of terminology consistency in translations of economic texts is currently emphasized by the Latvian State Language Center and determined by the fact that many economic terms emerged in Latvian and Russian relatively recently, during the transition from a planned economy to a market economy. It remains disputable how to define and assess the terminology consistency in translations of economic texts. The corpus of the study comprises Latvian and Russian textbooks on economics of three generations (1990s, 2000s and 2010s), and in addition to them - bilingual and multilingual dictionaries of economic terms published in Latvia and Russia since 1990. The paper proves that that terminology consistency in translations of economic (and not only) texts can be assessed and compared (between text corpora and time periods) using scientific methodology and a special technique. The method of research are linguistic discourse analysis, which includes both quantitative and qualitative methods. General results, which also form the scientific novelty of this study include: (1) the put forward conceptual understanding of the terminology consistency as the structural component of the overall quality of terminology translation as well as the definition of the terminology consistency in translations; (2) the elaborated original methodology and technique for assessing the terminology consistency in translations not in the categories of ‘good-bad’, but in the conditionally ambivalent categories ‘consistent-inconsistent’ (for the incidental identification of processes occurring in the studied economic discourse); (3) the explained essence of discourse in translation studies, which is the target text within the background processes of the social reality that determine the creation (synthesis) and perception (analysis) of the translation.
Background and Objectives: Preterm birth is the leading cause of neonatal mortality worldwide and may be responsible for lifelong morbidities in the survivors. Cervical shortening is one of the common pathways to preterm birth associated with its own diagnostic and management challenges. The preventive modalities that have been tested include progesterone supplementation and cervical cerclage and pessaries. The study aimed to assess the management strategies and outcomes in a group of patients with a short cervix during pregnancy or cervical insufficiency. Materials and Methods: Seventy patients from the Riga Maternity Hospital in Riga, Latvia, were included in the prospective longitudinal cohort study between 2017 and 2021. Patients were treated with progesterone, cerclage, and/or pessaries. The signs of intra-amniotic infection/inflammation were assessed, and antibacterial therapy was given when the signs were positive. Results: The rates of PTB were 43.6% (n = 17), 45.5% (n = 5), 61.1% (n = 11), and 50.0% (n = 1) in progesterone only, cerclage, pessary, and cerclage plus pesssary groups, respectively. The progesterone therapy was associated with a reduced preterm birth risk (x2(1) = 6.937, p = 0.008)), whereas positive signs of intra-amniotic infection/inflammation significantly predicted the risk of preterm birth (p = 0.005, OR = 3.82, 95% [CI 1.31-11.11]). Conclusions: A short cervix and bulging membranes, both indicators of intra-amniotic infection/inflammation, are the key risk factors in preterm birth risk predictions. Progesterone supplementation should remain at the forefront of preterm birth prevention. Among patients with a short cervix and especially complex anamnesis, the preterm rates remain high. The successful management of patients with cervical shortening lies between the consensus-based approach for screening, follow-up, and treatment on the one side and personalising medical therapy on the other.
The present work describes the synthesis of the new benzanthrone dye-3-[4-(2-phenylethyl)piperazin-1-yl]-7H-benzo[de]anthracen-7-one by bromine atom nucleophilic substitution reaction. The structure of the obtained benzanthrone derivative is characterized by NMR spectroscopy, mass spectrometry, and X-ray diffraction analysis. The photophysical properties of the target compound are investigated by means of UV-Vis and fluorescence spectroscopy in various organic solvents.
Citation: Pupins, M.; Nekrasova, O.; Tytar, V.; Garkajs, A.; Petrov, I.; Morozova, A.; Theissinger, K.; Ceirāns, A.; Skute, A.; Georges, J.-Y. Geographically Isolated Wetlands as a Reserve for the Conservation of Amphibian Biodiversity at the Edge of Their Range. Diversity 2023, 15, 461. Abstract: Wetlands are of great importance for biodiversity and nature conservation, especially geographically isolated wetlands (GIW). Yet literature about the ecological value of such GIW is missing, especially at the edge of the distribution of endangered species such as amphibians. In 2018 and 2022, we monitored amphibian communities in 15 isolated (GIW) and 12 non-isolated (nGIW) ponds by counting individuals using three methods: (1) capturing with hand nets, (2) visual counting, and (3) capturing with fyke traps. The three methods provided similar results, showing the great importance of GIW for amphibians, especially newts, whose abundance was 5-13 times greater in GIW compared to nGIW. The largest numbers of species and individuals (adults and larvae) were found in isolated wetlands (GIW). In non-isolated water bodies (nGIW) where more than 10 individuals of the Chinese sleeper Perccottus glenii, an alien invasive fish, were found, amphibians were not found at all. Importantly, between 2018 and 2022, the northern crested newt, T. cristatus, dramatically decreased in the nGIW. As a result of our work, it was revealed that the reconstruction of geographically isolated wetlands is very important for the conservation of amphibian biodiversity in a changing climate. One of the most effective measures aimed at protecting amphibians from negative factors-the spread of alien invasive fish species and diseases-is the reconstruction of wetlands in historically exploited landscapes with the creation of a wide range of water bodies yet broadly dominated by geographically isolated ponds.
This study seeks to determine whether patients from a family physician’s practice have an association between 25(OH)D levels and primary arterial hypertension (AH). The study included a total of 1068 patients who were tested for vitamin D status. Data from their outpatient medical records were analysed: sex, age, body mass index, glomerular filtration rate, and the history of AH. Primary arterial hypertension was diagnosed in 63% of the patients. The mean vitamin D level in the study population was 25 ng/ml, and the largest group, or 36%, was found to have vitamin D deficiency (20–29 ng/ml). Odds ratio (OR) for hypertension was not inversely correlated with higher vitamin D levels. No statistically significant increase was observed in OR in a multi-factor analysis. The relevant hypertension ORs were 1.8 (0.4–7.5), 1.1 (0.3–4.5), 1.7 (0.4–7.2) and 0.7 (0.1–4.8) 30 ng/ml to 45 ng/ml, 20 to 29 ng/ml, 10 to 19 ng/ml, and < 10 ng/ml compared to the group of ³ 45 ng/ml. No association was found between 25(OH)D levels and the primary arterial hypertension in study participants.
This is the first of two papers addressing language barriers in criminological discourse. The present paper rehearses arguments for comparative criminological research and identifies the administrative processes of journals leading to acceptance or rejection role of language as a contributory factor acting against the interests of those lacking fluency in a journal’s specified language of submission. Revisions of the common editorial practices of peer-reviewed journals are suggested. The potential contribution of machine translation is discussed.
This article presents an updated list of annotated invasive trees and shrubs in Latvia. This list includes 178 taxa about which extensive information has been collected and analysed: family, first records in the area, native range, invasiveness status, vector of introduction, and species distribution in Latvia. In this article, the authors, for the first time in Latvia, provided an invasiveness risk assessment and distinguished risk classes for trees and shrubs. The methodology previously developed by E. Weber and D. Gut was used to assess the risk of invasiveness. The most widely represented families in the list of invasive trees and shrubs are Rosaceae (51 taxa or 28.65%) and Salicaceae (20 taxa or 11.24%). Having assessed the invasiveness status, two species (Acer negundo L. and Sorbaria sorbifolia (L.) A. Braun) were identified as transformers, and 42 tree and shrub taxa were identified as invasive. After the assessment of the invasiveness risk, the species were divided into three risk classes. The highest risk class includes 32 taxa that are threatening or are likely to threaten natural habitats in Latvia in the future. The results of this study can be used for further dendrological studies in relation to global change and for practical nature conservation and landscape gardening
In the modern world, when the problems of the environment are most acutely associated with climate change, amphibians are considered to be the most vulnerable group of anamniotes as an indicator of the state of wetlands. Along with a decrease of numbers among amphibians in Europe, nowadays newts especially suffer from the impact of invasive species, in particular predators such as the Chinese sleeper, Perccottus glenii. This predatory fish species has recently spread to areas of primary relevance for newt reproduction. This fish consumes eggs, larvae, and even adult newt individuals. Using an ecological niche approach and climate based species distribution models (SDM), we applied the coefficient of determination (R 2) for comparing the level of similarity of the built SDM for the newts Triturus cristatus and Lissotriton vulgaris, and the Chinese sleeper. We show that by 2050, the level of climatic niche similarity for these native and invasive species will increase from 12% to 22% throughout Europe, and from 44% to 66% in Eastern Europe. This study highlights the expansion of the Chinese sleeper as a real threat to European biodiversity of wetlands in the near future, especially in their most northeastern distribution range.
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270 members
Arvīds Barševskis
  • Institute of Life Sciences and Technology, Coleopterological Research center
Juris Soms
  • Dept. of Environmental Science and Chemistry
Vadims Krasko
  • Department of Economics
Armands Gritsans
  • Department of Physics and Mathematics
Daugavpils, Latvia
Head of institution
Arvīds Barševskis