The growth data and the potential returns from 15-year-old plantations of pine Pinus sylvestris L. (6 trial sites), spruce Picea abies Karst L. (9 trial sites) and silver birch Betula pendula Roth (13 trial sites), established in abandoned agricultural lands in a variety of soil types (sod calcareous, anthrosols, podzolic, podzols, gley, podzolic gley, alluvial), using the planting density 2,500 and 3,300 and also 5,000 trees/ha are analysed. For tree plantations in agricultural soils (alluvial sod-gley, gley-sod podzolic, sod-podzolic gley, typic podzol) at the survival of 80-98% the stock volume for 15-year pine is as high as 102-155 m**3haE−1 with the volume growth 5.72-8.94 m**3haE−1 per year; the same indices for spruce in agricultural soils (gley sod-calcareous, sodpodzolic, cultivated, sod-podzolic gley, alluvial sod-gley, base-unsaturated brown) are 75-98 m**3haE−1 and 10.26-15.76 m**3haE−1, respectively. For 15-year plantation birch the mentioned indices may vary from 61 to 169 m**3haE−1 and from 7.54 to 29.82 m**3haE−1 per year. The lowest volume growth (4.66 m**3haE−1 per year) is for birch in heavy clay soil (gleyic sod-podzolic), the highest (29.72-29.82 m**3haE−1 per year) – in cultivated soils and pseudogley soil. Plantation cultivation of pine, spruce and birch in agricultural lands may by the age of 15 years yield with a profit such forest products as pulpwood, fire wood and woody biomass. The gross income gained from first commercial thinnings of plantation pine, utilizing pulpwood, fire wood and logging residue biomass, may vary from 679-2267 EUR haE−1, for spruce the same indices are 1644-3272 EUR haE−1, for birch - 683-2188 EUR haE−1.

It is well known that wood tends to shrink and swell as the relative humidity of the air changes. There have been, and still are, attempts to make dimensionally stable wood panels such as Dendrolight®. The physical-mechanical, operational, including acoustic, properties of this material have been significantly improved compared to traditional wood-based panels. However, the production of this material requires very specific processing equipment and a large energy investment. The developers of this material in Latvia invented and patented wood, Lightweight Stabilised Blockboard (LSB). In order for this material to be used in the production of various products, it is necessary to clarify its characteristic, technological, as well as operational properties. The study gathers information about the sound absorption properties of various natural and wood materials, characteristics, and the sound absorption of the studied material at different sound frequencies. The reviewed sources of information indicate that nowadays there are still problems in sound conduction and absorption and isolation issues are being addressed in building acoustics. The production of samples and the determination of sound absorption were carried out using a developed methodology developed in accordance with regulatory requirements. The data obtained in the practical study were compared with the relevant indicators of the Dendrolight® and wood-based panels used for building structures and to determine their compliance with the requirements set forth in the standards ISO 10534-2 and ISO 11654. Research data show that LSB corresponds to E sound absorption class in some of the investigated frequencies.

Yoghurt has been known as an excellent source for delivering viable lactic acid bacteria (LAB) in concentrations providing benefits to the human host and microbiome. Different gastrointestinal tract (GIT) simulators have been developed and are successfully used to determine the viability of LAB from fermented dairy products in vitro studies. Commercial yoghurts were tested for digestibility using the GIT IT system Labfors 5 (INFORS HT, Switzerland). The length for both the gastric phase and the small intestinal phase was 120 min each. Yoghurt LAB colony-forming units were analysed prior to the GIT simulation test, as well as after the simulation test. The survival rate of LAB was evaluated based on the differences in the viable LAB count at the beginning and at the end of the experiment. Tested yoghurts’ LAB were tolerated in the simulated gastric and small intestinal phases. Samples collected prior to and after the intestinal phase revealed that LAB had adapted and started to grow within 120 min. Our results showed the ability of LAB to recover in the intestinal phase which has been explained by the food matrix, which protects the bacteria from the elimination effect of intestinal secretions. In addition, differences in survival rates of LAB significantly influenced the overall LAB colony-forming units in the gastrointestial tract. The chemical composition of the product has an influence on the survival rate of LAB, and it should be studied more thoroughly. In vitro studies are quite different from the assay in vivo studies; however, this information provides significant data about the viability of LAB from regularly consumed products and helps to modulate the influence of LAB on human microbiota.

In order to address existing and foreseen climate change and environmental challenges, the European Commission has adopted a set of proposals as part of the European Green Deal to reduce emissions of greenhouse gases and become the first climate-neutral continent in the world. In the energy sector it is planned to implement specific actions to increase the contribution from renewable sources of energy. Livestock manure as a renewable resource can be processed to produce biogas through anaerobic digestion processes. This study aimed to estimate the amount of livestock manure potentially available for biogas production in Latvia based on statistical information on the number of animals representing current and past trends, and forecasts for the future provided by the results of the Latvian Agricultural Sector Analysis Model (LASAM). The results of this study showed that the share of livestock manure processed to produce biogas has increased considerably during the time period from 2010 to 2019 in all groups of livestock considered for this application in Latvia. However, there are still opportunities to increase the share of manure utilised for anaerobic digestion, especially in the livestock groups of dairy cows and non-dairy cows, as only 16% and 13% of the available amount of manure was processed in 2019, respectively. The LASAM results indicate that the number of animals will experience negligible changes or will decrease; therefore, more attention will need to be paid to increase the efficiency of processing the existing amount of manure rather than relying on an additional amount of manure available for biogas production.