خيارات البحث
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Fatty acid composition of the meat of elk, deer, roe deer and wild boar hunted in Latvia
2012
Strazdina, V., Latvia Univ. of Agriculture, Jelgava (Latvia) | Jemeljanovs, A., Latvia Univ. of Agriculture, Jelgava (Latvia) | Sterna, V., Latvia Univ. of Agriculture, Jelgava (Latvia)
Every autumn and winter period, game animals - elk (Alces alces), deer (Cervus elaphus), roe deer (Capreolus capreolus) and wild boar (Sus scrofa scrofa) - provide an excellent input in the diversification of many consumer meals. In the recent years, consumption and assortment of game meat products has significantly increased. At the moment there are only few biochemical composition investigations of the game meat. The meat of wild animals is more favourable for human health, because it has a lower content of saturated fatty acid, but a higher content of protein. Therefore the aim of our investigation was to compare biochemical composition of the game meats hunted in Latvia. Investigations were carried out in different regions of Latvia. In the studied samples, protein, intramuscular fat, fatty acids and cholesterol were determined. The biochemical analysis of 54 samples was carried out. The results of the analysis showed that protein content in all types of the meat samples was 22.36 - 22.92%, which is not statistically significant. The fat content, on the other hand, was significantly lower: 1.33 ± 0.88% in elk meat samples, and 1.59 ± 0.59% in roe deer meat samples. Content of cholesterol varied from 64.41% to 95.07% in the ruminant meat samples of different species. From the dietetic point of view, the meat samples of roe deer had the best composition of fatty acids.
اظهر المزيد [+] اقل [-]Antimicrobial resistance of animal pathogens 2006-2009 in Estonia
2012
Aasmaee, B., Estonian Univ. of Life Sciences, Tartu (Estonia) | Kalmus, P., Estonian Univ. of Life Sciences, Tartu (Estonia)
The present study describes situation of antimicrobial resistance of animal pathogens and resistance trends in Estonia in years 2006-2009. Bacterial strains isolated during period 2006-2009 were Escherichia coli (E. coli), Enterococcus faecium (E. faecium), Enterococcus faecalis (E. faecalis), collected from healthy pigs faeces as well as from diagnostic submissions of pig samples. Staphylococcus aureus (S. aureus) isolates originated from cows with clinical mastitis and Staphylococcus pseudointermedius (S. pseudointermedius) isolates from dogs with pyoderma or otitis externa. Antimicrobial susceptibility was detected by microdilution method. Normal enteric microflora from health y pigs had resistance against streptomycin, tetracyclin, sulfametoxazol and trimethoprim. E. faecalis and E. faecium were resistant to erythromycin, tetracyclin, streptomycin and kanamycin. Multiresistance occured mainly against kanamycin, streptomycin and tetracyclin. E. coli strains isolated from pathological material showed high resistance to ampicillin, tetracycline, streptomycin, sulphonamides and trimethoprim. Multiresistance was detected between 60–73% during study years. In 2009, one ESBL (extended spectrum betalactamase) producing isolate was observed. S. aureus strains isolated from clinical mastitis samples were mainly penicillin resistant (58–86%). Meticillinresistant S. aureus was not found during the study. In 2009, resistance to lincomycin (30%) and fucidinic acid (22%) was detected. In S. pseudointermedius strains isolated from canine skin samples the prevalence of resistance to penicillin as high as 53–81% was found. Multidrug resistance was relatively stable being 38% in 2006, 29% in 2007 and 25% in 2009. In conclusion, antimicrobial resistance of animal pathogens in Estonia was high. Further improvement of prudent use of antimicrobials and infection control is needed.
اظهر المزيد [+] اقل [-]Aortic lumen diameter and blood pressure changes dynamics after replacing aorta abdominalis with prosthesis
2012
Malniece, A., Latvia Univ. of Agriculture, Jelgava (Latvia) | Auzans, A., Latvia Univ. of Agriculture, Jelgava (Latvia) | Drevinska, K., Latvia Univ. of Agriculture, Jelgava (Latvia)
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.
اظهر المزيد [+] اقل [-]Solid fuel boiler automation for briquette use
2012
Komass, T., Latvia Univ. of Agriculture, Jelgava (Latvia)
Nowadays all engineering technologies are based on the automation, but still there are some processes that are not easy to automate. One of them is the heating process using solid fuel boilers. The paper deals with automated double-link air flow control of the combustion process. The research target was to find more effective solutions of furnace air flow regulation to improve the combustion process efficiency. The research object was a 56 kW wood briquettes water heating boiler. The results of the experiment research show a higher efficiency of the combustion process with double-link air flow PI control using motor valves.
اظهر المزيد [+] اقل [-]Dynamic model of biochemical network of Zymomonas mobilis adaptation for glycerol conversion into bioethanol
2012
Odzina, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
One of the biodiesel production problems is occurrence of a significant quantity (about 10%) of the by-product – glycerol. This problem is offered to solve by adaptation of bacteria Zymomonas mobilis, which is notable for ethanol production facilities. To be able to process glycerine into ethanol using Z.mobilis bacteria, the bacteria must be modified. At the same time, computer modelling analysis is required to assess specific modification affectivity in interconnection with other processes in bacteria. Computer model results of simulated experiment to understand and predict that the cells and biological processes are essential to reduce the number of experiments. This in turn reduces the necessary financial resources and time, bio-medical biotechnology, pharmaceutical and environmental problems. The model describes conversion of glycerol into bioethanol in Z.mobilis bacterial cell. First phase of model creation is creation of a structure model based on biochemical reactions using computer software CellDesigner. On the second phase of model creation, kinetic parameters which are available in literature were identified. Using the databases KEGG, SABIO-RK, BRENDA, reactants, kinetic parameters and reaction equation types were defined. Dynamic model of Z. mobilis biochemical network was created using computer software Copasi. The dynamic model describes conversion of glycerol into bioethanol in Z.mobilis bacterial cell. In this time simulation data of the computer model of natural organisms are not to confirm laboratory experimental data. Simulation data of the computer model are not correct to prevent this problem is required parameter estimation in computer software COPASI.
اظهر المزيد [+] اقل [-]Some peculiarities of laboratory measured hyperspectral reflectance characteristics of Scots pine and Norway spruce needles
2012
Masaitis, G., Aleksandras Stulginskis Univ., Akademija, Kauno reg. (Lithuania) | Mozgeris, G., Aleksandras Stulginskis Univ., Akademija, Kauno reg. (Lithuania)
The aim of the study was to investigate the properties of hyperspectral reflectance data of Scots pine (Pinus Sylvestris L.) and Norway spruce (Picea Abies L.). The hyperspectral reflectance data was obtained under laboratory conditions from the last season’s needles of healthy 20 year-old trees from the same site. Hyperspectral data was acquired using Themis Vision Systems LLC VNIR 400H portable scanning hyperspectral imaging camera in 400-1000 nm range. Methods of analysis of variance, discriminant analysis and principal component analysis were applied for the hyperspectral data analysis. Differences between Scots pine and Norway spruce reflection data were examined. The most informative spectral range for Norway spruce – Scots pine spectral separation was determined at 666.5 nm – 668.4 nm, most informative waveband - 667.1 nm. Reflectance variations among individual trees of the same species as well as differences in spectral response between needles from northern – southern crown exposition were tested. A significant variation in spectral response of needles of Norway spruce was detected across the whole measured spectral range (955 wavebands) for each sample tree. However, significant variation of spectral response of needles of Scots pine was detected only in 356 out of 955 wavebands for each sample tree. Depending on the crown exposition to the North or South, the reflectance of Scots pine needles differed significantly in 900 spectral bands. No significant differences were detected in 833 wavebands for Norway spruce.
اظهر المزيد [+] اقل [-]Evaluation of results of forest regeneration after stump extraction in Finland
2012
Lazdins, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Mattila, M., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
The interest in stumps has increased with recent boost of the bioenergy in Europe. Fuel yield from stumps can be as high as from harvesting residues. The most valuable areas for stump extraction are spruce and pine stands on dry mineral soils. In Finland the utilization of stumps for energy is rapidly moving from the testing phase to forest practice. In 2005 the use of stump wood chips by heating and power plants totalled 0.4 mill. m**3, tripled the consumption of 2004, which corresponds to 14% of the total consumption of forest chips in Finland. Extensive whole-tree harvesting trials in Sweden demonstrate that removal of stumps and slash from clear-felled sites has a strong positive impact on natural forest regeneration. Results from Finland indicate that stump and slash removal can improve productivity and quality of subsequent re-planting of harvested forest sites. The majority of available studies on root rot control demonstrate that subsequent forest regeneration is more successful on sites where the stumps have been removed. The scope of this study was to evaluate quality of forest regeneration after stump extraction in Finland according to the national regulations in Latvia. Number, size, distribution and mortality of seedlings were estimated in 15 compartments. Additionally, moisture and compaction of soils were determined. Results of the study approved that regeneration of forest stands on fertile mineral soils after stump extraction was successful and combination of mounding with scarification during stump extraction provides sufficient growing conditions for new seedlings.
اظهر المزيد [+] اقل [-]Impact of provenance on wood and fibres properties of lodgepole pine, grown in Latvia
2012
Sable, I., Latvia Univ. of Agriculture, Jelgava (Latvia);Latvian State Inst. of Wood Chemistry, Riga (Latvia) | Grinfelds, U., Latvian State Inst. of Wood Chemistry, Riga (Latvia) | Sisenis, L., Latvia Univ. of Agriculture, Jelgava (Latvia) | Verovkins, A., Latvian State Inst. of Wood Chemistry, Riga (Latvia) | Treimanis, A., Latvian State Inst. of Wood Chemistry, Riga (Latvia)
Lodgepole pine (Pinus contorta) samples from three different provenances in Canada were investigated. All trees were the same age and had been grown in Latvia in similar conditions. Lodgepole pine of Summit Lake provenance had higher wood density (503 kg m-3) and a higher late wood content (46%) in comparison to Fort Nelson and Pink Mountain provenances. Investigation of chemical composition of wood indicated Summit Lake provenance wood as superior in cellulose content (49.7%), but no differences in lignin and extractives content were found between samples. Kraft pulp yield of Summit Lake samples (48%) was the highest, but the handsheet strength properties were relatively higher for pulp from Pink Mountain provenance pine wood.
اظهر المزيد [+] اقل [-]Scots pine (Pinus sylvestris L.) stem wood and bark moisture and density influencing factors
2012
Millers, M., Latvia Univ. of Agriculture, Jelgava (Latvia) | Magaznieks, J., Latvia Univ. of Agriculture, Jelgava (Latvia)
Latvia uses average moisture content and density indexes obtained in Russia and European countries; though, these indexes are different, and there is no information about the most suitable one for conditions in Latvia. Research complex on Latvia’s industrially important tree species - Scots pine (Pinus sylvestris L.) stemwood and bark moisture and density changes, depending on influencing factors, is being conducted at Forestry Faculty of Latvian University of Agriculture. The research results on Scots pine, obtained during the year 2011 in the whole territory of Latvia, are outlined in this article. Wood and bark moisture and density were analyzed in 21 sampling plots, arranged in middle aged and cutting-aged reached forest stands, depending on tree age, cutting time and location place in the tree stem. The average moisture content of pine wood mostly depends on heartwood specific weight and age of the tree. With an increase of tree age, average wood moisture content value decreases from 111% (40-year-old trees) to 77% (145-year-old trees). Scots pine heartwood moisture content changes a little during the year: 30– 34% for 71 to 146-year-old trees; and 34-41% for 37–70-year-old trees. Sapwood moisture content is changes from 113% (in the summer) to 130% (in the winter), without any reference to the age of the tree. The average density of oven dry timber obtained from 71–146-year-old trees in the research is 0.501 g cmE-3, whereas in freshly cut condition – 0.848 g cmE-3.
اظهر المزيد [+] اقل [-]Contamination problems in former military areas: case study in Riga [Latvia]
2012
Burlakovs, J., University of Latvia, Riga (Latvia) | Gorbunovs, E., University of Latvia, Riga (Latvia)
Contamination of urban areas is directly connected with the lack of adequate waste management planning. Problems mostly arise in former military bases, garages, warehouses and areas with other facilities. For many decades environmental problems caused by pollution in areas of military use were not managed in Latvia. The aim of this research is to assess visual environmental quality and study heavy metal contents in soil of ‘Jaunais Mežaparks’ after demolishing works in the capital of Latvia – Riga, as well as to provide comparison to the former military ‘Daugavgrīva’ site. Research was carried out from November 2011 to February 2012 by soil sampling and further analysis and comparison of the heavy metal content in soil with target and boundary levels in legislation. ‘Jaunais Mežaparks’ is a former military area which is planned to be reused in future. The former military site is planned to be used as the residential neighborhood and is situated close to important recreational object in Mežaparks area – Lake Ķīšezers. According to Riga Development Plan old military sites must be remediated in accordance with environmental legislation if the contamination exceeds critical concentration values. Thus, this case study includes assessment of visual pollution as well as soil heavy metal contamination study. Recommended actions as well as direct remediation technologies to reduce the poisonous impact of contamination to environment in this area are proposed.
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