خيارات البحث
النتائج 1631 - 1640 من 2,098
Susceptibility of faba bean variety ‘Merkurʼ to broadbean seed beetle (Bruchus rufimanus) in Latvia
2024
Gailis, Janis | Grase, Zane Gita | Ozolina-Pole, Laura
The broadbean seed beetle (Bruchus rufimanus) is a significant pest of faba bean (Vicia faba) both in Latvia and in many other parts of the world. The objective of this study was to check the susceptibility of the faba bean variety ‘Merkurʼ to the broadbean seed beetle in Latvia, comparing it with other popular varieties: ‘Boxerʼ and ‘Lauraʼ. The trials were conducted in 2021 and 2022 at the Research and Study Farm ‘Peterlaukiʼ in Jelgava County and at a commercial farm in Cēsis County. The larval infestation rate of seeds of different varieties, the survival rate of individuals (larvae, pupae, imagines) in the seeds, as well as the percentage of seeds damaged by the pest in the yield were compared. It was observed that ‘Merkurʼ seeds were significantly less infested than ‘Boxerʼ and ‘Lauraʼ seeds. However, the survival rate of larvae in the seeds of ‘Merkurʼ was similar to that in ‘Lauraʼ seeds and higher than in ‘Boxerʼ seeds. The highest proportion of seeds damaged by the pest was found in the ‘Merkurʼ and ‘Boxerʼ yields, varying between 5–75% between years and trial locations. Therefore, it was concluded that the variety ‘Merkurʼ, evaluated from a practical point of view, does not differ from the other two varieties. Without taking additional plant protection measures, the percentage of seeds damaged by the broadbean seed beetle can significantly exceed the maximum limit (3%) specified in the buyersʼ quality criteria.
اظهر المزيد [+] اقل [-]Detection of coronavirus among domestic animals
2024
Sadikaliyeva, Sandugash | Shorayeva, Kamshat | Abay, Zhandos | Jekebekov, Kuanish | Shayakhmetov, Yeraly
This article presents the results of studies on biological samples collected from 640 swabs taken from dogs and cats across various regions of the Republic of Kazakhstan. These samples were part of a monitoring study on the spread of coronavirus among domestic animals. Total RNAs were isolated using the magnetic sorption method with the ALPREP kit and subsequently analysed with the ALSENSE-SARS-CoV-2 RT-qPCR kit. Real-time RT-PCR analysis revealed that 104 samples tested positive within 22–37 amplification cycles. These positive samples were then cultured in Vero cell lines to confirm the presence of the virus. The biological activity of the resulting virus-containing suspension was determined using the Reed-Muench method. During cultivation, one viral isolate with a biological activity of 5.83±0.08 lg TCID50/ml was obtained. A microphotograph of the virus was taken using an electron microscope to determine its size, shape, and structure, which confirmed its morphology corresponding to the Coronaviridae family. The data obtained further indicate that domestic animals can suffer from and carry coronavirus. It is becoming increasingly evident that the virus can infect and replicate in the organs of various farm and domestic animals.
اظهر المزيد [+] اقل [-]Responses of hybrid Aspen in vitro cultures to different proportions of red and blue light
2024
Kondratovičs, Toms | Burša, Margarita Daina | Auziņa, Magda Lote
Light is one of the most significant environmental factors affecting the growth of plants, as it is the driving force of photosynthesis. Among others, the red and blue light are the most relevant, as these spectral regions are absorbed by chlorophyll the most. In addition, red and blue light trigger specific photomorphogenic responses that allow plants to capture the available light efficiently. Accordingly, the proportion of red and blue light (R:B ratio) is considered one of the most important characteristics of light for plants, as optimal R:B provides balanced growth and photosynthesis. The aim of this study was to evaluate how the in vitro cultures of hybrid aspen (Populus tremula L. × P. tremuloides Michx.) are affected by different R:B ratios under fixed illumination intensity. We examined the growth characteristics of plantlets under wide spectrum LED luminaires with three different R:B proportions – 1:1, 7:3 and 9:1. While photosynthesis-related variables were significantly affected by light, the effect on morphology was less pronounced. Overall, increased proportions of red light decreased the photosynthetic performance of plantlets without giving significant benefits in the form of longer shoots that could be used to facilitate propagation effectiveness. Nonetheless, the effect of light treatment remains at least partially clones-specific and should be considered in case of further application for propagation purposes.
اظهر المزيد [+] اقل [-]Radial growth response of Japanese walnut (Juglans ailantifolia) to meteorological conditions in Latvia
2024
Jansone, Diāna | Matisons, Roberts | Straupe, Inga | Jansons, Āris
The introduction of non-native tree species has been used as a climate change mitigation tool. To ensure the anticipated benefits, the analysis of species radial growth reactions to meteorological factors should be carried out. Initially, tree species were introduced to non-native regions as food resources, yet the focus has now shifted towards favourable wood properties and growth rates. This study used tree ring width measurements of Japanese walnut Juglans ailantifolia and climate data to examine the relationships between these variables. A total of 30 trees were sampled from a stand located in the southern part of Latvia. Tree ring width (TRW) was measured, and residual chronology was derived. Pearson correlation analysis was used to detect the correlating meteorological factors, and a linear mixed-effects model was used to detect the key factors. The correlation analysis indicated generally low correlation coefficients between TRW and meteorological factors, primarily correlating with summer precipitation, both the current and preceding summer, highlighting carry-over effects. Furthermore, signature years underscored the negative effect of low temperatures and summer droughts on the radial growth of Japanese walnuts. However, the observed variation in TRW between years, not fully explained by meteorological factors, suggests a dynamic rather than stable relationship.
اظهر المزيد [+] اقل [-]The evaluation of tan spot phenotype and the presence of necrotrophic effectors in the population of Pyrenophora tritici-repentis in Latvia
2024
Kaņeps, Jānis | Bankina, Biruta | Moročko-Bičevska, Inga
Tan spot is an economically important disease of wheat in Latvia, but there is still insufficient information about its causal agent’s Pyrenophora tritici-repentis diversity in Latvia. The aim of this study was to evaluate the disease phenotype in the field and the possible presence of necrotrophic effectors Ptr ToxA, Ptr ToxB and Ptr ToxC in the P. tritici-repentis population in Latvia. Typical differential wheat lines ‘Glenlea’, ‘6B662’, ‘6B365’ and ‘Salamouni’ were evaluated under the field conditions in 2023 in the central part of Latvia. The highest tan spot severity was observed during the flowering stage with no significant difference between wheat genotypes. During the experiment, the typical disease phenotypes corresponding to all three known effectors were noted. Additionally, typical tan spot symptoms were determined on the resistant cultivar ‘Salamouni’, confirming the presence of new, currently uncharacterised effectors that are not compatible with the existing race model. Future studies should focus on searching for new effectors and further characterising known necrotrophic effectors, as knowledge about P. tritici-repentis and wheat interaction is still incomplete.
اظهر المزيد [+] اقل [-]Measurement of sustainable entrepreneurship – benefits in a BREEZE: A review
2024
Bormane, Santa | Tiuncika, Lasma
When it comes to moving towards sustainable entrepreneurship, a knowledge-based economy is starting to affect companies and how they are managed. It is relevant for researchers and entrepreneurs to evaluate different sustainability aspects and look for ways how to achieve entrepreneurship sustainability. In the past couple of decades, many indicators have been developed which measure the performance of sustainable entrepreneurship. Not all cover a sufficient basis to provide a thorough evaluation, though. The goal of the study was to evaluate the expertise in sustainable entrepreneurship among large companies with metrics identified in the latest scientific literature review. In the process of the literature review, authors identified key metrics to measure the performance of sustainable entrepreneurship and split them into six groups. They mostly focus on social, environmental, and economic performance measurement. Relatively few research results mention the importance of corporate management indicators. Thus, the key metrics are distinctive by including corporate management as a separate aspect in the performance measurement. The conceptual framework is represented by the acronym BREEZE, including 6 groups of key metrics: brand awareness and consumer behaviour, responsibility for society and employees, environmentally friendly materials, ease of use and reuse (disposal), zero waste, economic performance (approbated on focus group discussion and expert interviews). The results revealed that the expertise levels in sustainable entrepreneurship among the large companies are fair. Complementary data analyses were carried out; as a result, authors developed a self-evaluation matrix in sustainable entrepreneurship.
اظهر المزيد [+] اقل [-]Adaptation to the Covid-19 crisis: Case study analysis of social economy actors in Latvia
2024
Licite-Kurbe, Lasma
Covid-19 has affected the whole economy of Latvia, leading to various social and economic problems in the country. Social economy actors applying an innovative approach to solving social problems could make a significant contribution to improvement in social life, especially during the Covid-19 crisis and the post-crisis by supplying various services and products, helping the state to solve gaps that it cannot cope with without the help of the private or non-governmental sector. The research aims to describe the challenges faced by social economy actors in Latvia during Covid-19 and their responses to the crisis. The research employed case study analysis to describe the responses of 9 social economy organizations to mitigate the consequences of the crisis. The research found that Covid-19 had a negative impact on the performance of social economy actors faced by financial, organizational, social and psychological challenges, which overall did not significantly differ from those faced by other market actors in the particular situation. To solve the current problems in society and ensure their self-existence, social economy actors implemented an innovating strategy that focused on three priorities: new digital experiences, products and services in response to changes in customer behaviours and needs; development of new offers for a new or the current target group; new partnerships both within and outside the industry.
اظهر المزيد [+] اقل [-]Private pension funds in Latvia: Investment strategies and performance of pension plans
2024
Mazure, Gunita
Private pension plans envisage a voluntary choice of a person to make additional savings for the retirement by joining a private pension plan and making contributions. In 2023, six open private pension funds offered twenty pension plans. Private pension funds provide three types of investment strategies: conservative, balanced and active ones. The research aim is to assess the performance of the private pension plans in Latvia. The research is based on the analysis of the statistical data on the return of assets and other performance indicators of private pension plans as well as it employs the correlation and regression analyses. The data analysis shows a steady increase (annually 6.24% on average) in the population participation in private pension plans. Active plan participants account for 51.42% on average, while the proportion of deferred participants is also large, i.e. 30.40% on average. Short-term returns of private pension plans are very fluctuating with expressive increases and decreases where the active pension plans demonstrated the most unstable return trends. The sharpest return decline was observed in 2022, when the arithmetic total average return of all private pension plans was – 14.63%. The basic reasons mentioned are the changes in investment portfolio, global downturn of stock markets and sharp growth of inflation. Long-term returns show a positive growth through the entire period analysed, i.e. 4.16% on average. This means that a short-term decline of returns does not signal of future decrease in the amount of pension, since contributions to pension plans are considered to be a long-term investment.
اظهر المزيد [+] اقل [-]Sustainable marketing: Challenges and opportunities in context of consumer behaviour
2024
Rozensteina, Dace | Bormane, Santa
The society has changed its habits, and public demand requires a more extensive offer of environmentally friendly goods and services on the market, including more products of plant origin. New plant-based products continuously appear on the market. As competition in the segment of plant-based beverages intensifies, brands are forced into differentiating their products by including elements of sustainable marketing in their marketing materials to induce consumers into making purchase decisions and purchases. This study aims to find out which sustainable marketing elements contribute to consumer decisions to purchase and consume plant-based beverages. The article presents the results and trends based on the 1st stage of the study – a pilot survey and structured in-depth expert interviews. The pilot survey identified the key sustainable marketing elements in consumer decisions to purchase plant-based beverages: product availability at food supermarkets; advertising at point of sale indicating price discounts; healthy product composition and raw materials; convenient in-store placement, price discounts and natural raw materials, etc. Based on the results of the pilot survey, there were changes made in the consumer questionnaire, and the 2nd stage of the study – a survey of the Latvian population to find out the complex factors affecting consumer buying decisions – was launched in February 2024.
اظهر المزيد [+] اقل [-]Health self-evaluation: Are there differences in rural and urban territories in Latvia
2024
Sloka, Biruta | Tora, Ginta | Seimuškāne, Lilita | Angena, Anna
Recent developments in politics and economy has created additional challenges for medical institutions with lack of medical personnel, transportation from rural areas to medical institutions. Very often, there is a difference between medical services in urban and rural areas. In research is often mentioned that male and female persons have different evaluations on their health situation. The aim of the paper is to prepare research based recommendations for possible steps for public administrators to support availability of medical services in urban and rural areas. Tasks of the current research: analysis of theoretical findings reflected in scientific publications and discussion of research results, analysis of tendencies of self-perceived health status of population in Latvia, analysis on possible differences between gender as in scientific publications is often mentioned that female and male persons have different evaluations, analysis of health self-evaluations between inhabitants in rural and urban territories and possible differences in evaluations for persons with different employment status. Representative data from EUSILC, different statistical analysis methods and statistical indicators are used: indicators of descriptive statistics, crosstabulations, testing of statistical hypotheses with t-test and analysis of variance – ANOVA, chi-square test, as well as correlation analysis. Research results confirm that self-perceived health status in Latvia are higher in rural areas and higher health self-esteem evaluations were made by female persons.
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