Experimental self-binding high-density fibreboard is produced of the grey alder (Alnus incana L. Moench) steam-exploded fibres without addition of synthetic adhesives. Milled grey alder chips are processed in steam-explosion unit by saturated steam under pressure of 3.2 MPa at temperature of 235 deg C for 1 min in a 0.5 l batch reactor. The steam-exploded fibres are pressed at 160 deg C temperature under 8 MPa pressure for 10 min in three steps. Properties, such as density, swelling in thickness, water absorption, bending strength, modulus of elasticity at bending, and internal bonding strength of the studied fibreboard samples are reported. Differences between the raw milled chippings and the exploded fibres are observed by scanning electron microscope. The study is focused on modified technical options of the steam-explosion unit supplied with two containers receiving different kinds of the exploded biomass farther used to obtain the hot-pressed boards. The cascade of the receivers is explained in a presently pending patent. The self-binding high-density fibreboard samples show the following properties comparable to commercial products: density of at least 1.35 g cmE-3, moisture content of 7.2%, swelling in thickness of 8.1%, water absorption of 3.2%, bending strength of 27 N mmE-2, modulus of elasticity of 6,259 N mmE-2, and internal bonding of 0.92 N mmE-2.

The urban forest is recognized as a potential to improve the quality of life of urban dwellers and increase the sustainability and ecological stability of the city. However, there is little data on professional attitude to urban naturalistic landscapes. This research studies the attitude of professionals and decision makers to the naturalistic forest landscapes in urban area of Riga city, Latvia, in contrast to more traditional – formal landscape. The survey includes the opinions of territorial planners and environment specialists from Riga municipality and other institutions related to ecological, practical, planning and conservation activities, and private working landscape architects. The statistical analysis and data’s empirical distribution showed that professionals in Riga city recognize the values and benefits of naturalistic forest landscape. However, environmental preferences may depend more on affective reactions than on ecologically-based logical operations.

Reduced fertility associated with fluid accumulation has been recognized for many years in broodmares. Fluid present in the uterus after ovulation is often associated with mare susceptibility to endometritis. Objective of this study was to determine amount of intrauterine fluid secretion and endometrial oedema in mares at the time of artificial insemination (AI), 6 h, 25 h, and 48 h after AI and at the time of ovulation. A total of 22 cycling light breed mares from MTT Agrifood Research, Ypaja, Finland, were used in the study. Relaxation of the cervix, the number and size of follicles, corpus luteum, and the degree of endometrial oedema were examined by transrectal palpation and ultrasonography every other day. According to the closing and opening time of the cervix which was regulated using Bivona catheter, mares were distributed into 3groups. Group A (n=7): immediately after artificial insemination (AI) the catheter was inserted into the uterus. After 25 h, the catheter was opened and the fluid drained. Group B (n=8): immediately after AI, Bivona catheter was inserted into the uterus. After 6 h and 25 h the catheter was opened and the fluid drained. Group C (n=7)-control group: no catheter was inserted into the uterus. According to our investigation, we concluded that the amount of intrauterine fluid accumulation (IUFA) in mares increased within 25 h after AI. Mares with delayed uterine clearance had a significantly larger amount of intrauterine fluid than mares with normal uterine clearance. Open cervix during oestrus period is important for adequate clearance of intrauterine fluid in mares. Opening of intrauterine catheter at 6 h post AI didn’t diminish intrauterine fluid accumulation at 25 h post AI.

The production of innovative composition (high omega group fatty acids and antioxidants-carotenoids) broiler chicken meat and egg opportunities in Latvia was assessed. After feeding the poultry with feed enriched with fatty acids and antioxidants, broiler meat and eggs of innovative composition containing a higher amount of omega-3 (in meat by 1.7%, in eggs by 2.7%), omega-6 (in meat by 3.9%, in eggs by 3.2%) and carotenoids (0.44 mg kg-1 in meat and in eggs by 6.9 mg kg-1) when compared with the content of commercial products are obtained. Nutrition costs of innovative composition-based broiler chicken meat production are LVL 20 higher and nutrition costs of egg production are LVL 1.49 higher per 1000 units of output than in the standard version of the poultry feeding-stuff. The poultry farming production of an innovative composition, however, is economically profitable due to the higher rates of poultry productivity. In the case of an innovative composition-based yield the potential profit at the currently equal cost realisation of poultry meat and eggs is higher when calculating 293.47 LVL per 1000 broiler chickens and 5.52 LVL per 1000 eggs in comparison with commercial production.

Pollution and treatment efficiency of surface (rain) wastewater, forming in the production territory of meat processing company LTD ‘Krekenavos mėsa’ (centre of Lithuania in Kėdainiai district), were investigated in the period 2004-2009. On the surface of the company territory the precipitation water turns to surface wastewater, which is collected and sent down to treatment equipment. Wastewater samples were taken before and after biological treatment. The samples were investigated in the Chemical Analysis Laboratory of the Water Research institute of Lithuania University of Agriculture certified by the Environment Ministry of the Republic of Lithuania The following indices have been determined: biochemical oxygen demand (BOD7) – by titrometric method, suspended solids (SS) – by gravimetric method, having filtered the substance through a mid-thickness filter. Concentrations of oil pollutants were determined with the help of a spectrophotometric device of infrared rays IKAN-1 in the Analytical Department of Agrochemical Study Center of Lithuanian Agricultural Institute. During six years of investigation average wastewater pollution with suspended materials was 35.0 mg LE-1, which by 14% exceeded the BAC. Suspended solids determined BOD7 concentrations in surface wastewater by 46%. The best treatment effect was received in the purification of oil products - 96%, suspended solids - 60%, organic pollutants - 59%. The wastewater discharged from the company production territory to natural environment was clean as concentrations of the investigated oil hydrocarbons, biochemical oxygen demand and suspended solids in the surface wastewater were 26, 4 and 2 times respectively lower than biggest available concentration.

The objective of the present studies is to estimate a distribution of nitrogen and phosphorus compounds in filter media of horizontal filters. The studies were carried out in 2009 within two wastewater treatment facilities of horizontal flow in Lithuania. From both treatment facilities sand samples of different depth and separate profiles in the direction of water flow were taken. These samples were used to determine sandmoisture and concentration of N-NO3, N-NH4 and total P. The measurements of sand moisture showed that the filtration of wastewater through the sand is in process only in the lower layer of sand filter and near the distribution pipe. Moisture regime in the sand influences the composition of nitrogenous compounds in it. In the part of the filter, where sand's moisture is lowest, nitrate concentration is highest. Ammonia concentrations are completely opposite. In the lower part of the filter anaerobic conditions are dominant and nitrification processes stop. Analysis of phosphorus concentrations in filter's sand showed similar tendencies as nitrogen analysis. In the upper part of the sand phosphorus concentration turns out to be 2-3 times lower than in the lower part of the sand. In the filters of horizontal flow, part of the sand contributes little or does not contribute to the wastewater treatment process at all; therefore, it is advisable to use wastewater recirculation for the improvement of nitrogen and phosphorus removal. For that purpose in the part of the filter not included in the treatment process the filter of vertical flow could be arranged.

The interaction between short fibres and concrete in the post-cracking phase influences crack spacing and width in the composite. In order to perform analysis of deformation of a composite and the fibre displacement at the crack, single fibre was examined. A two-fibre model considering the distribution of fibre length and incomplete bonding was developed. Numerical analysis reveals that two-fibre model analysis is believed to be more accurate than that obtained from the single-fibre analysis. Comparing the solution of the single-fibre and two-fibre system shows that the latter gives a greater fibre displacement at the crack. The study was performed in the Department of Structural Engineering, year 2009/2010.

Today e-learning is a term which is commonly used, but does not have a universally accepted definition, but it can be considered as technology-enhanced learning, where all types of digital technologies are used to support the learning process. Over the years some new functionality has appeared as mobile and wireless technologies (m-learning) and digital television provided possibilities for interactive study materials management (tv-learning). Latest options for training process acceleration are offered by virtual and augmented reality (VR/AR) technologies. The aim of this paper is to find solution for appropriate hardware selection before constructing VR/AR system for training needs focusing on platforms used for operators preparation to work with industrial equipment. In the beginning of the paper all hardware devices for such systems are summarized and explained. Then by using set theory and combinatorics all possible sets of input/output devices are described and calculated. Next dynamic modelling is used to create deterministic, static simulation model with an aim to ease the process of hardware selection for VR/AR training systems development. Simulation model is used for development of two pilot projects.

Approach of white box mathematical modelling was used to develop dynamic mathematical model of glycerol cycle in baker's yeast Saccharomyces cerevisiae and by deterministic simulations explore an interaction between glycerol cycle and glycolysis. The key process in research was reaction of artificially expressed glycerol-2-dehydrogenase (Gld2) which catalyses glycerol transition into dihydroxyacetone and reduced nicotinamide adenine dinucleotide phosphate (NADPH). We put forward hypothesis that expression of Gld2 in S. cerevisiae could increase concentration of reduced cytosolic NADPH. Michaelis-Menten equation was used to describe a rate law of reactions of the model of glycerol cycle. Kinetic parameters Km (Michaelis - Menten constant) and Vmax (maximal velocity of reaction) were taken from BRENDA database and publications. To perform deterministic simulations of the model of glycerol cycle and glycolysis, an accomplished model of glycerol cycle was introduced into the mathematical model of glycolysis of Nielsen et al. (1998). Results suggested that Gld2 reaction could run even without glycolysis as long as glycerol and oxidized nicotinamide adenine dinucleotide phosphate (NADP+) was present in the system. Intracellular concentration of glycerol had a direct impact on formation and acumulation of dihydroxyacetone. Reduced nicotinamide adenine dinucleotide (NADH) concentration decreased significantly and rapidly when glycerol cycle was switched on suggesting that it could be a limiting factor of the system.

The aim of the study: to analyse the principle of exemplarity, comprehend its features and their usage in university exact courses learning practice. The principle of exemplarity is a means of arranging the geodesy study course programme according to the most essential notions of the course and students abilities and knowledge level at Latvia University of Agriculture. It is one of the cognitive learning didactical principles proponed by the German scientist Martin Wagenschein and recognised in a teaching/learning process particularly in natural sciences. The origination of the principle of exemplarity, its relevant features and experience of other countries are analysed in the article. The following notions of the principle are analysed in the article: coping with information quantity, comprehension of a course entity and epistemology, interdisciplinarity; usage of exemplar as a feature of entity criterion in obtaining particular knowledge and skills; traits of Socratic dialogue. The principle of exemplarity is combined with problem-based learning, project method and student-centred approach and is used and discussed particularly in Germany and Denmark. The principle features and the ideas of its usage are being assessed, worked in and implemented in the geodesy study course programme for the land survey speciality first year students. The programme is revised thematically determining the focal themes (exemplars) in laboratory works via which the principle of exemplarity can be the means of obtaining the course of geodesy successfully.