University of Latvia
Recent publications
Vaccination is the most effective way of limiting the spread of COVID-19. However, despite the proven effectiveness and safety of vaccines, there is resistance in society and the course of vaccination is slow. The aim of this study was to identify the factors associated with COVID-19 vaccination behaviour. Methods: The data originate from a representative sample of Latvian residents (N = 1017) taken in September 2021. The data were analysed using Chi-squared test, Mann-Whitney test, Spearman's rank correlation coefficient, Kruskal Wallis test, and Binary Logistic regression analysis. Results: The results of the study reveal several factors that are associated with COVID-19 vaccination behaviour. These factors are a higher level of education, motivation for protecting oneself against illness, for promoting collective immunity, protecting relatives and other people from infection, as well as motivation for vaccination in order to keep a job or continue studies, and institutional trust. On the other hand, perceived social support from relatives is negatively associated with vaccination behaviour. Conclusion: A higher level of education and confidence in evidence-based information on COVID-19, provided by official sources of information, is the key factor in deciding whether to protect oneself from serious illness or to make a choice to promote collective immunity and protect other people. The need for vaccination in order to continue working and/or learning is also an essential motive for vaccination. On the other hand, the belief that, if necessary, it is possible to receive support from relatives may be a delaying factor in the behaviour of vaccination.
Though carbonates are known for several decades, their role in sun-light driven photocatalysis is still hidden. Herein, carbonate boosted solar water splitting in nickel-based plasmonic hybrid nanostructures is disclosed for the first time via in-situ experiments and density-functional theory (DFT)-based calculations. [email protected]/NiCO3 [email protected] (shell consisting of crystalline NiO and amorphous NiCO3) nanostructure with varying size and compositions are studied for hydrogen production. The visible light absorption at ∼470 nm excludes the possibility of NiO as an active photocatalyst, emphasizing plasmon driven H2 evolution. Under white light irradiation, higher hydrogen yield of ∼80 µmol/g/h for vacuum annealed sample over pristine (∼50 µmol/g/h) complements the spectroscopic data and DFT results, uncovering amorphous NiCO3 as an active site for H2 absorption due to its unique electronic structure. This conclusion also supports the time-resolved photoluminescence results, indicating that the plasmonic electrons originating from Ni are transferred to NiCO3 via NiO. The H2 evolution rate can further be enhanced and tuned by the incorporation of NiO between Ni and NiCO3.
Combining defect semiconductors Ga2S3 and Ga2Se3 in Ga2O3-based heterostructured nanowires (NWs) have potential in photonics and optoelectronics applications due to the materials appealing optical properties. In this work, we have developed and studied Ga2O3-Ga2S3 and, for the first time, Ga2O3-Ga2Se3 core-shell NWs. Ga2S3 and Ga2Se3 shell was obtained during high-temperature sulfurization and selenization process of pure Ga2O3 NWs, respectively, in a chemical vapour transport reactor. As-grown nanostructures were characterized with scanning and transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and photoluminescence measurements. Single-nanowire photodetector devices were fabricated in order to demonstrate their electric and photoconductive properties. Such novel core-shell NW heterostructures could potentially be used in next-generation nanoscale electronic and optoelectronic devices.
Russia launched an unprovoked full-scale invasion of the sovereign country of Ukraine. This movement was historic as people around the world watched the events unfold, and before our eyes, the world watched a country be destroyed and civilians lose their homes, schools, hospitals, and lives. The invasion on February 24, 2022, was particularly emotional feeling incredibly close to home in countries like Latvia that also lost its independence in a similar manner just generations before. This is the visual representation of the events by the people of Latvia for the people of Ukraine during the first 2 weeks following the invasion.
Recent years have witnessed an increase in bear sightings in Latvia, causing a change of tone in the country's media outlets, regarding the return of "wild" animals. The unease around bear reappearance leads me to investigate the affective side of relations with beings that show strength and resilience in more-than-human encounters in human-inhabited spaces. These relations are characterized by the contrasting human feelings of alienation vis-à-vis their environments today and a false sense of security, resulting in disbelief to encounter beings capable of challenging human exceptionalism. In a broader sense, the unease connects to human self-constitution and the fragility of the self, fueled by the domination of substance ontologies. This article considers bears as beings "in exile," as potential threats to human self-pronounced exceptionality, and thus, examples of experienced abject (Kristeva, Julia. Powers of Horror: An Essay on Abjection, translated by Leon Roudiez. New York: Columbia University Press, 1982) regarding human subjectivity. The article aims to analyze the way the constitution of human selfhood is tied to the alienation of wildlife and its genealogical and biopolitical context and to question if a reconceptualization of the human/nonhuman relations via process, instead of substance ontology, is needed.
The SSIS SEL Brief Scales (SSIS SELb) are multi-informant (teacher, parent, and student) measures that were developed to efficiently assess the SEL competencies of school-age youth in the United States. Recently, the SSIS SELb was translated into multiple languages for use in a multi-site study across six European countries (Croatia, Greece, Italy, Latvia, Portugal, and Romania). The purpose of the current study was to examine concurrent and predictive evidence for the SEL Composite scores from the translated versions of the SSIS SELb Scales. Results indicated that SSIS SELb Composite scores demonstrated expected positive concurrent and predictive relationships with scores from the Connor-Davidson Resilience Scale (CD-RISC) and negative relationships with scores from the problem behavior scales of the Strengths and Difficulties Questionnaire (SDQ). Although there were a few exceptions, these patterns generally were consistent across informants (parents, teachers, and students) and samples providing initial validity evidence for the Composite score from the translated versions of the SSIS SELb Scales. Limitations and future research directions are discussed.
This study reports the first dietary stable isotope data from Iron Age in Latvia. Archaeological, osteological, genetic, and stable isotope data from the Lejasbitēni cemetery were used to study gendered differences in childhood diet expressed in stable isotope ratios with social status expressed in grave goods, in this population from the 7th – 10th centuries CE. Carbon and nitrogen isotope analysis showed significant differences in childhood diet between male and female gendered individuals, indicating that gender might have been a key factor for dietary differences in children. There were no significant dietary differences within the gender groups in adults of differential social status expressed in grave goods, suggesting no link between childhood diet and social status in adulthood, although the sample size was very small. A change towards a more hierarchical society was observed in the later period of the cemetery, expressed in the appearance of more elaborately furnished burials, rare grave goods, and a new burial tradition. All these changes were contemporary with the development of the Viking Age in Northern Europe, and thus possibly signified external cultural influence. Ancient DNA analysis showed that gender as expressed by grave goods corresponded with biological sex in two individuals with the highest quality aDNA, while biological sex could not be confirmed in the other five tested individuals.
Objectives The consequences of long-lasting restrictions related to the COVID-19 pandemic have become a topical question in the latest research. The present study aims to analyze longitudinal changes in adolescents’ social emotional skills, resilience, and behavioral problems. Moreover, the study addresses the impact of adolescents’ social emotional learning on changes in their resilience and behavioral problems over the course of seven months of the pandemic. Methods The Time 1 (T1) and Time 2 (T2) measuring points were in October 2020 and May 2021, characterized by high mortality rates and strict restrictions in Europe. For all three countries combined, 512 questionnaires were answered by both adolescents (aged 11-13 and 14-16 years) and their parents. The SSIS-SEL and SDQ student self-report and parent forms were used to evaluate adolescents’ social emotional skills and behavioral problems. The CD-RISC-10 scale was administered to adolescents to measure their self-reported resilience. Several multilevel models were fitted to investigate the changes in adolescents’ social emotional skills, resilience, and behavioral problems, controlling for age and gender. Correlation analysis was carried out to investigate how changes in the adolescents’ social emotional skills were associated with changes in their resilience and mental health adjustment. Results Comparing T1 and T2 evaluations, adolescents claim they have more behavioral problems, have less social emotional skills, and are less prosocial than perceived by their parents, and this result applies across all countries and age groups. Both informants agree that COVID-19 had a negative impact, reporting an increment in the mean internalizing and externalizing difficulties scores and reductions in social emotional skills, prosocial behavior, and resilience scores. However, these changes are not very conspicuous, and most of them are not significant. Correlation analysis shows that changes in adolescents’ social emotional skills are negatively and significantly related to changes in internalized and externalized problems and positively and significantly related to changes in prosocial behavior and resilience. This implies that adolescents who experienced larger development in social emotional learning also experienced more increase in resilience and prosocial behavior and a decrease in difficulties. Conclusion Due to its longitudinal design, sample size, and multi-informant approach, this study adds to a deeper understanding of the pandemic’s consequences on adolescents’ mental health.
Introduction: Insulin pump therapy represents an alternative to multiple daily injections and can improve glycemic control and quality of life (QoL) in Type 1 diabetes mellitus (T1DM) patients. We aimed to explore the differences and factors related to the T1DM-specific QoL of such patients in Latvia. Design and methods: A mixed-method cross-sectional study on 87 adult T1DM patients included 20 pump users and 67 users of injections who participated in the quantitative part of the study; 8 pump users and 13 injection users participated in the qualitative part. Patients were invited to participate using a dedicated digital platform. Their QoL and self-management habits were assessed using specially developed questionnaires adapted to Latvian conditions. Multiple logistic regression models were built to investigate the association between social and self-management factors and patients’ QoL. In addition, qualitative analysis of answers was performed. Results: Insulin pump users were younger, had higher incomes, and reported higher T1DM expenses than users of multiple daily injections. There were no differences in self-management between the groups; Total QoL differed at the 0.1 significance level. In fully adjusted multiple logistic regression models, the most important factor that increased Total QoL was lower T1DM-related expenses (odds ratio, OR 7.02 [95% confidence interval 1.29; 38.0]). Men and those with more years of living with T1DM had better QoL (OR 9.62 [2.20; 42.1] and OR 1.16 [1.05; 1.29], respectively), but the method of administration was not significantly associated with QoL (OR 7.38 [0.87; 62.9]). Qualitative data supported the results of quantitative analysis. Conclusions: QoL was the main reason to use an insulin pump, while the expense was the main reason to avoid the use of it or to stop using it. Reimbursement policies thus should be considered to enable patients to choose the more convenient method for themselves.
Within the Human Biomonitoring for Europe initiative (HBM4EU), a study to determine new biomarkers of exposure to pesticides and to assess exposure patterns was conducted. Human urine samples (N=2,088) were collected from five European regions in two different seasons. The objective of the study was to identify pesticides and their metabolites in collected urine samples with a harmonized suspect screening approach based on liquid chromatography coupled to high resolution mass spectrometry (LC-HRMS) applied in five laboratories. A combined data processing workflow included comprehensive data reduction, correction of mass error and retention time (RT) drifts, isotopic pattern analysis, adduct and elemental composition annotation, finalized by a mining of the elemental compositions for possible annotations of pesticide metabolites. The obtained tentative annotations (n=498) were used for acquiring representative data-dependent tandem mass spectra (MS²) and verified by spectral comparison to reference spectra generated from commercially available reference standards or produced through human liver S9 in-vitro incubation experiments. 14 parent pesticides and 71 metabolites (including 16 glucuronide and 11 sulfate conjugates) were detected. Collectively these related to 46 unique pesticides. For the remaining tentative annotations either (i) no data-dependent MS² spectra could be acquired, (ii) the spectral purity was too low for sufficient matching, or (iii) RTs indicated a wrong annotation, leaving potential for more pesticides and/or their metabolites being confirmed in further studies. Thus, the reported results are reflecting only a part of the possible pesticide exposure.
In this article, we provide access to, and information on the production of 42 ecogeographical variables (EGVs) used to describe the landscape of Latvia at three scales (local and two landscape). Layers are focused on the description of forest heterogeneity, but account for other ecosystems and land cover types as well. The more temporarily changing land use and land cover (LULC) types as forest and agricultural lands are described from 2017 databases. With most of the other LULC information was gathered from the topographic map (2016) at the scale of 1:10 000. All the raster layers provided here are in the Latvian projected coordinate reference system (epsg:3059) with a grid cell size of 25ha. Each layer provides quantitative information on the area, shape, and edge of habitat classes and additionally, age, time since the last forestry disturbance, relative soil humidity, relative soil richness etc. for forests. The three scales represent information from within 25ha grid cell, and two radii – 1250 and 2500 m - around the center of the grid cell.
Reflecting upon the implications of Russia’s invasion of Ukraine for the theorization of ‘diaspora diplomacy’, this Provocation uses the concept to frame the conflict and the ensuing power plays. The extent of global community involvement requires the existing diaspora diplomacy definition to account for ‘quadratic nexus’ configuration of ‘home’ and ‘host’ country, respective diasporas and international actor engagement in diaspora diplomacy practice. In reviewing the conflict, and the current response, four themes emerge as central to the ‘quadratic nexus’ configuration and deserving further attention: the politics of labelling, the dynamics of engagement, third-party diasporas and diaspora identities in diaspora diplomacy.
Pollen monitoring has traditionally been carried out using manual methods first developed in the early 1950s. Although this technique has been recently standardised, it suffers from several drawbacks, notably data usually only being available with a delay of 3–9 days and usually delivered at a daily resolution. Several automatic instruments have come on to the market over the past few years, with more new devices also under development. This paper provides a comprehensive overview of all available and developing automatic instruments, how they measure, how they identify airborne pollen, what impacts measurement quality, as well as what potential there is for further advancement in the field of bioaerosol monitoring.
Context The paper studies the possibilities of how the cultural explosion theory and path dependence approach could be used for exploring landscape (change). The former is an approach (not theory) used in humanities and social sciences to study the processes that happen when culture changes rapidly—how new cultural processes are created and how the past ones are integrated or forgotten. The latter is an approach developed also in social sciences, mostly economy, to study how the current decisions are dependent on the past decisions. Objectives To demonstrate the possibilities the two theoretical approaches might offer. Methods We discuss the ways landscape change could be analysed using, first, cultural explosion theory and, second path dependence approach, and demonstrate this on the example of the post-Soviet military areas. Results Both approaches are indeed useful in understanding landscape change. The demo case on military landscapes allows for distinguishing three different development paths for the future of the areas: set-aside, active use, and neglect. Similarly three different ways of relating with the past are found: ignorance and oblivion; acknowledging the past; and making use of the past. Conclusions Landscapes have time boundaries and these two analytical tools in fact help us to navigate through these boundaries, understand better the trajectories of change and the importance (or the lack of it) of the past.
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4,451 members
Vyacheslavs Kashcheyevs
  • Faculty of Physics and Mathematics
Mihails Hazans
  • Institute of Philosophy and Sociology
Olga Muter
  • Institute of Microbiology and Biotechnology
Reinis Rutkis
  • Institute of Microbiology and Biotechnology
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Indriķis Muižnieks
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www.lu.lv
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