The most important part in forest inventory based on remote sensing data is individual tree identification, because only when the tree is identified, we can try to determine its characteristic features. The objective of research was to explore remote sensing methods to determine individual tree position using LiDAR and digital aerial photography in Latvian forest conditions. The study site was a forest in the middle of Latvia – in Jelgava district (56º39’ N, 23º47’ E). Aerial photography camera (ADS 40) and laser scanner (ALS 50 II) were used to capture the data. LiDAR resolution was 9p m2 (500 m altitude). The image data is RGB, NIR and PAN spectrum with 20 cm pixel resolution. Image processing was made using Fourier transform, frequency filtering, and reverse Fourier transform. LiDAR data processing methods was based on canopy height model, Gaussian mask, and local maxima. Field measurements were tree coordinates, species, height, diameter at breast height, crown width and length. Using combined LiDAR and optical imagery data allows detecting at least 63% of all trees and about 85% of the dominant trees.

The aim of this study was to find out the biointegration of innovative vascular prosthesis, made in Riga Technical University (RTU), in dog’s abdominal aorta. The research is being performed in Veterinary Medicine Faculty of Latvia University of Agriculture since July 19. 2011. We used 9 female gender and 1-3 years old Beagle dogs in this study. The research is approved by the Latvian Republic Food and Veterinary Service. The study is carried out in the frame of European Social Fund co-financed project ‘Establishment of interdisciplinary research groups for a new functional properties of smart textiles development and integrating in innovative products’ (ESF No. 2009/0198/1DP/1.1.1.2.0./09/APIA/VIAA/148). 5-8 mm in diameter, 8 mm - 18 mm in length RTU produced aortic grafts were implanted retroperitoneal in dogs. Before the surgery the diameter of abdominal aorta was measured in cross sections, afterwards – cranial and caudal from the prosthesis, as well cross-section diameter of vascular graft was measured. Blood pressure was measured before the surgery and after the procedure on regular basis. Results are the following: there are no significant differences in aortic and graft diameter before and 1-2 months after the operation, there are no significant differences in systolic and diastolic blood pressure before and four months after the surgery at significance level α = 0.05. The study shows that the innovative aortic prostheses don’t change in diameter, and surgery like abdominal aorta transplantation doesn’t cause significant variations in blood pressure. The study is being continued to find out later reactions to synthetic vascular graft.

The article focuses on vegetation diversity in the black alder Alnus glutinosa (L.) Gaertn. woodland key habitats in Zemgale, Latvia. Together nine sample plots were established on these habitat types, where next stand South – South West (S-SW) side at the age 1-10; 20-30 and 40-50 years. The vegetation survey has been made in vegetation period of 2010 and 2011. Braun – Blanque method has been used to estimate the projective coverage (%) of tree layer (E3), shrub layer (E2), herb layer (E1) and moss layer (E0) in order to assess the edge effect impact on vegetation diversity according to different ages classes in a next stands of sample plots. The analysis of edge effect verifies that there is a significant influence from the edge in 1st and 3rd zones of sample plots, which lies at S-SW side at the ages 1-10 and 20-30. In sample plots several indicator species of black alder woodland key habitats have been found: Vaccinium myrtillus L., Lycopus europaeus L., Iris pseudacorus L., Comarum palustre L., Plagiomnium ellipticum (Brid.)T.kop. Ordination confirmed that composition of species are relatively close, which demonstrate that species are able to live in similar type growing conditions. Protective species Circaea lutetiana L. and Plagiothecium undulatum (Hedw.) B., S. et G were found on the study sites. Also, adventive species Impatiens parviflora DC was found. Comparing the analysis by zones and sample plots and different age classes, the impact on edge effect has been distinguished in black alder woodland key habitats.

The rowanberries (Sorbus aucuparia L.) are small orange-red fruits of a rowan tree and belong to the family Rosaceae. These berries have been described as an important source of flavonoids, and their antioxidant activity affects reactive oxygen species and lipid peroxidation; therefore they are suitable for production of health-food products. The ripe wild rowanberries have traditionally been used for jellies and jams, but their use as a food ingredient has been less popular because of their bitter taste. Sweeter and less astringent than wild rowanberries are different cultivars of sweet rowanberries and hybrids with other species. The aim of the current research was to determine physical and chemical parameters and sensory properties of rowanberry marmalades. The experiments were carried out in the Faculty of Food Technology of Latvia University of Agriculture. The purees of wild rowanberry and six different rowanberry cultivars were chosen for the production of marmalades. Chemical, physical and sensory indices of the product – moisture, total carotenoids, tannins, colour, hardness and intensity of sensory properties (flavour, colour, bitterness) – were determined as quality indicators. The results showed large variability in the physical and chemical parameters between the marmalades of different rowanberry cultivars and hybrids. The sensory evaluation of marmalades from rowanberry cultivars ‘Moravica’, ‘Mitchurinskaya krasnaya’, ‘Sorbinka’ and hybrid of rowanberry × hawthorn ‘Granatnaya’ showed that the degree of liking was from “neither like nor dislike” to “like moderately”, and marmalades from wild rowanberry, S. aucuparia var. sibirica and hybrid of rowanberry × pear ‘Alaya Krupnaya’ – from “dislike moderately” to “dislike slightly”.

The aim of the research is to find out how participation of students in international scientific conferences influences the development of their academic skills in foreign languages. The use of foreign languages in the academic study and research has increased in recent years. At the Latvia University of Agriculture in co-operation with three faculties – the Faculty of Social Sciences, the Faculty of Engineering and the Forest Faculty such conferences have been organized already for six years. The students of all other faculties of the university are also participating with their reports and publications. Student conferences being extra-curriculum activities form the environment where foreign languages play an important role being not only the languages of the contributions but also they are used in the process of communication among the conference participants from different countries. An enquiry among the participants of the conference is presented and the results are analysed.

In order to perceive the pressure oscillation in the hydraulic hitch-system of the tractor and oscillation of the whole tractor aggregate at different loads on the hitch-system, a physical model is used. Changing the position of weight on physical implement boom, different moments of inertia were obtained and the appropriate load on the hydraulic hitch-system hydro cylinder. Results of driving experiments on the artificial roughness road present the maximum pressure peak of 220 bar in the tractor hydraulic system when weight was placed on further position, and the driving speed was 8 km hE-1 and tyre pressure was 1.2 bar. At the driving speed of 11.2 km hE-1 and with the same tyre pressure, the hydraulic system pressures reached up to 212 bar. On the weight on the middle position of boom, pressure in the hydraulic hitch-system reached 172 bar at the driving speed of 7.8 km hE-1 and tyre pressure of 1.2 bar, but at the driving speed of 11.2 km hE-1 and at the same tyre pressure, the hydraulic system pressures reached 165 bar. If the weight was placed on nearest position, pressure in the hydraulic hitch-system reached only 85 bar at the driving speed of 7.8 km hE-1 and tyre pressure - 1.2 bar, but at the driving speed of 11.2 km hE-1 and at the same tyre pressure, it was 98 bar. The investigation of the physical tractor-implement model allows the determination of the conformity of the physical model with real harrow implement.

The number of high school students and young people, who are willing to pursue studies, has rapidly decreased in our country and a lot of young people are leaving to look for employment opportunities abroad. Therefore, the introducing of E-studies is one of the possibilities to continue schooling. However, there is an important question, whether high school students are aware of such a form of studies and whether they are ready for it, and how many of them are prepared for it. Education as a social institution is usually perceived as a body of organizations, approved by society, in which training of diverse kinds and levels is implemented. Learning and teaching is the basis of the educational institution. E-University is a type of educational institutions, and e-studies are a form of teaching and learning.

One of the causes of cardiovascular diseases and overweight problem is a high consumption of sweets. Sugar is traditional food sweet matter. A change of sugar may therefore both change the perception of texture of products. The aim of the research was to evaluate properties of agar-agar jellies prepared with Jerusalem artichoke (Helianthus tuberosus L.) syrup (JAS). Soluble dry matter of experimental samples was determined by Mettler Toledo Refracto, separated sugars - by liquid chromatography, and acidity of jellies - by titration with 0.1 M NaOH. The measurements of pH were made by pH-meter Jenway 3510. Determination of vitamins B1 and B2 was made by the AOAC Official Method 986.27 and 970.65. Texture of samples was determined by using a Texture Analyser (Model TA.XT Plus; Stable Micro Systems), by cylindrical probe (P/25). Colour of jellies was evaluated by using Colour Tec-PCM. The results showed that soluble dry matter decreased from 64.5˚ Brix to 57.5˚ Brix, sucrose decreased by 6%, the acidity increased from 7.2 to 17.8˚, and pH values ranged between 3.8 and 4.5. The hardness of the samples decreased from 50.66N to 40.05N by increasing of added JAS concentration. Adding JAS in jelly, the content of vitamins B1 and B2 increased. Lightness “L” fluctuated between 24.26 and 14.60 with increase JAS concentration. The research suggests that different percents of Jerusalem artichoke syrup could be used as sugar substitute. The product becomes healthier, but the gels obtain a darker colour. Therefore it is recommended to look for other version to improve the colour of experimental jellies.

The objective of the present study was to investigate the microbiological content of cows’ milk in Latvia’s organic farms with a purpose to detect potential microbiological threats in milk. Samples were collected in December 2011 at 12 biological dairy farms of Latvia. Raw milk samples (N=155) obtained from cow composite milk were studied. The total mesophilic aerobic and facultative anaerobic microorganisms (MAFAM), the presence of coliforms and coagulase-positive staphylococci, count of yeasts and moulds were analysed using standard methods. Of the sampled cows 50% had a low somatic cell count (SCC) (LESS THAN 200,000 cells mLE-1), 23% - high, but 27% had a very high SCC (greater than 500,000 cells mLE-1). The mean value of MAFAM in the samples with low, high and very high SCC was 4.7, 5.0 and 5.0 log10 colony forming units (cfu) mLE-1, respectively. The yeasts were present in 57% of milk samples with the mean concentration of 3.1 log10 cfu mLE-1. Moulds were found in 27% of all milk samples; their mean concentration was 4.4 log10 cfu mLE-1. Identified mould strains belonged to genera Absidia, Aspergillus, Geotrichum, Mucor and Penicillium. In cases of subclinical mastitis and latent mammary infection the most distributed mastitis pathogens were Staphylococcus aureus, Micrococcus kristinae, Bacillus cereus and coagulase negative staphylococci.

This research was carried out to start the discussion on the amount of harmful emissions that are emitted in producing building and insulation materials for roof constructions. Usually, for the improvement of energy efficiency of buildings and reduction of the embodied thermal energy, effective thermal insulation solutions for the external building envelope have to be provided. From the buildings available for the analysis, in Latvia there were selected multi-apartment buildings of separate series with a uniform composition of roof constructions. Within the context of renovation works, the reports of energy audit for the buildings contain recommendations referred to improvement of the thermal performance of roofs. Using mutually comparable energy efficiency report data, there was drawn up an averaged model of a five-storey multi-apartment residential house. There were taken into account legislative documents relating to thermal engineering of buildings: LBN 002-01 ‘Heat engineering of building boundary constructions’ and LVS EN ISO 6946: 2007 ‘Building components and building elements – Thermal resistance and thermal transmittance’, and moisture regime according to LVS EN ISO 13788: 2001 ‘Hygrothermal performance of building components and building elements – internal surface temperature to avoid critical surface humidity and interspatial condensation – calculation methods’, which states that the roof constructions should be free from possibility of water vapour condensation. In this study, there were calculated energy savings obtained by improving thermal resistance of the roof constructions and the opposite primary energy consumption for the production of building materials. As a result, there is obtained environmentally friendly roof construction.