The possibilities to use other media instead of the sand in the filters of vertical flow are analysed in the article. The media used has to be inexpensive and its possibilities to clean the wastewater have to surpass that of the sand. The modelling of the wastewater treatment in the vertical flow filters was carried out in 2008 at the Water Research Institute of the Faculty of Water and Land Management of Lithuanian University of Agriculture. Dolomite powder was chosen for the investigation. Two models of 0.2 square m filters were made: one was filled with the sand, but the other was filled with the dolomite powder. It was found that the dolomite filter was less reactive to the primary contamination of the wastewater with the organic pollutants: when their amount rose from 320 to 460 mg O2 LE-1 according to the BOD7 index, the amount of the pollutants in the wastewater cleaned with the dolomite powder filter rose from 1.4 to 3.1 and amount in the wastewater which passed the sand filter rose from 0.5 to 13.9 mg O2 LE-1. General phosphorus was removed with the efficiency of 99.9% in the dolomite powder filter (and only with the efficiency of 87.0% in the sand filter). Therefore the dolomite powder filter will be removing phosphorus from the wastewater to the allowable contamination level for a much longer period. General nitrogen was cleaned with the effectiveness of 13.0% in the dolomite powder filter. Therefore, it is necessary to use additional means for its removal from the wastewater in the vertical filters with the output higher than 5 m**3 dE-1.

In order to avoid the problem of stoppage in the filters of vertical filtration, we tried to search for the filter media which was coarse and could clean the wastewater to the allowable contamination level. For this purpose the dolomite chippings were chosen and the modelling investigation was performed. Two modelled filters taking 0.2 square m area each were equipped: one was filled with the sand and the other was filled with the dolomite chippings. The results revealed that the initial contamination of the wastewater had a much bigger influence on the wastewater cleaning process than the hydraulic load. The wastewater was cleaned with the efficiency of 95.9% and never exceeded the allowable level of 30 mg O2 LE-1 in the dolomite chippings filter during the trial with the hydraulic load 0.03 m**3 mE-2 dE-1. When the hydraulic load was doubled the efficiency of the wastewater cleaning process decreased to 80.5% and the dependence of the cleaning process on the initial contamination of the wastewater increased. In order to ensure the successful removal of the easily decomposing organic pollutants from the wastewater up to their allowable contamination level, the quantity of the pollutants in the untreated wastewater must not exceed 220 mg O2 LE-1.

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 pollution of the river water with organic matter deteriorates the chemical, biological and microbiological quality of the water and has a negative effect upon the biological variety of the water environment. The paper analyses the study period (1996-2000) seasonal change of organic matter in the upper reaches of the River Nevezis (study sites upstream and downstream Panevezys). The highest amount of organic matter (according to chemical oxygen demand and biochemical oxygen demand) got into the river under the influence of concentrated pollution, the fewer amount - under the influence of agricultural pollution and in the course of natural processes. The concentration of organic substances in the river water had a seasonal character: rivers with a better ecological state (the Juosta) were more polluted with organic matter in spring, when water temperature was below 10 deg C, but rivers with a worse ecological state (the Nevezis upstream and downstream Panevezys) – in summer (water temperature was higher than 10 deg C). This may be related with fresh pollution; in the former case organic matter might have come from the environment together with the runoff, in the latter case - due to decomposition of water vegetation and fauna residues in the river itself. In all rivers water temperature was by 0.1-4.4 deg C higher in 1996-2000 in comparison to that in 1986-1989, a significant temperature increases were observed in winter and autumn. The water temperature arose mostly below the town.

A current investigation compared various intensive crop rotations (Norfolk, row crops, cereals, short term grass) grown on Cambisols. The study results showed significant effects of N-fertilization of the agroecosystem on mineral N concentration in drainage water and its leaching process. The highest N concentration in drainage water and leaching was determined in the conditions of cereals and row crops rotations. No major impact of the crop rotation on phosphates concentration in drainage water was determined. The average leaching of one by drainage did not exceed 100-140 g haE-1 within a 7 year study period. An experiment was arranged during 1997-2003 years in the Kėdainiai district, Lipliunai willage. A rational and well-considered fertilization ensures high crop productivity and profitable farming as well as steady, which is the main condition for reduced non-point source pollution of water.

Global warming undoubtedly influences the flow of rivers. It is essential to observe the climate changes, trace, analyse and forecast how they could influence the environment and, especially, how it can influence the flow of rivers. In this article two maximum flows of basins of two different rivers are analyzed: the river Venta (above Papile) and the river Krazante (above Pluskiai) during the period 1968–2008. Climatic parameters, such as the precipitation and the average air temperature, observed in the weather stations of Siauliai and Laukuva, influence the changes in flows the most. The correlation between the precipitation and maximum change of the flow was estimated though it was not strong: the ratio of correlation in the river Venta was 0.66, in the river Krazante the same ratio was 0.72. Significant negative trends of the both analyzed rivers during the spring period and significant negative trends of the river Venta during the period of winter have been established by the use of statistical analysis of the results obtained from a non-parametric Mann-Kendall test and linear regression test. This specific analysis is performed by using TREND programme. The collected data which were obtained to show that the most watery decade of the rivers Venta and Krazante were during the period 1978–1987, which formed 36% flow in the river of Venta and 35% in the river of Krazante for the whole period of forty years.

The environment relating to the history of civilization is the notion, which more and more is used when thinking about the changes occurring in Latvian culture. In this research are considered all Latvian palace and manor parks and classified as an integral part of the heritage. The research was done from the year of 2009 to 2010. Fundamental principles the quality of today’s parks were taken, first of all, evaluating the cartographical and historical materials and available literature sources, secondly, chosen, mostly historically rich and varied parks, evaluating basing on landscape evaluation criteria, and, thirdly, summarizing the qualified parks, for working out qualitative and sustainable park development models in the future researches. Working out the evaluation system and principles of historic parks, it is possible not only to reanimate the historical landscape, but also get back the total landscape atmosphere, in spite of the loss of the main ensembles or their partly ruination. The park qualification, structure investigation, landscape inventory and analysis, as well as European experience in historic landscape maintaining and development, according to a similar landscape structure, which nowadays successfully functions as a heritage, is the base for an optimal and sustainable culture landscape development. The worked out order helps in understanding and analyzing the meaning of the historic park and its successful development tendency, in which are marked out the most important heritage objects in the particular landscape and they are reverted in a vital pulse and social processes.

This paper focuses on evaluation of web browsing layout engines used as a backbone in web browsing software. Study of commonly used web browsers and Web information system developing languages has been performed. The role of web browsing layout engine evaluation in web information system development process is identified as a critical matter for bringing business processes online in a form of usable and accessible information system. By analyzing web browsing layout engines as a tool that renders elements on a particular Web page of web information system, key tendencies and emphasis for web information system developers are revealed and discussed.

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.