خيارات البحث
النتائج 501 - 510 من 2,098
Efficacy of the first large-scale rabies oral vaccination campaigns in Latvia
2011
Olsevskis, E., Latvia Univ. of Agriculture, Jelgava (Latvia);Food and Veterinary Service, Riga (Latvia);Institute of Food Safety, Animal Health and Environment BIOR, Riga (Latvia) | Liepins, E., Latvia Univ. of Agriculture, Jelgava (Latvia) | Lamberga, K., Food and Veterinary Service, Riga (Latvia) | Rodze, I., Institute of Food Safety, Animal Health and Environment BIOR, Riga (Latvia)
Rabies is present in the entire territory of Latvia and as a zoonosis poses risk to both human and animal health. The disease is also endemic in countries bordering with Latvia, namely Lithuania, Estonia, Russia and Belarus. Reservoirs for the rabies virus (RABV), the causative agent of the disease in Latvia, are the red fox (Vulpes vulpes) and the raccoon dog (Nyctereutes procyonoides). The first large-scale oral rabies vaccination campaigns using aircrafts were carried out in spring and autumn 2005 using Fuchsoral® SAD B19 oral vaccine baits. In total, 1,894 wild animals (1,366 foxes and 528 raccoon dogs) were hunted in vaccinated areas to evaluate the efficacy of the campaign. After spring and autumn vaccination campaigns, 51.6% of the fox and raccoon dogs were positive for tetracycline. Herd immunity was found in 50.5% of foxes and raccoon dogs using FAVN test and only in 14.8% using ELISA test. After oral vaccination campaigns, rabies incidence decreased in vaccinated area, however, an increase of the incidence was observed in unvaccinated area. Despite the slight increase in rabies incidence in Latvia in 2006 compared to 2005, in 2005 only 141 rabies cases (30%) were found in the vaccinated area whereas 330 cases were detected in the unvaccinated area.
اظهر المزيد [+] اقل [-]Development of experimental equipment for vegetable oil fuel research
2011
Birkavs, A., Latvia Univ. of Agriculture, Jelgava (Latvia) | Dukulis, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
The European Parliament and Council Directive 2003/30/EK ‘On the promotion of the use of biofuels and other renewable fuels for transport’ determines that pure or straight vegetable oil, produced from oil plants by pressing, extracting or comparable procedures, crude or refined but chemically unmodified, compatible with common engines, and corresponding to emission requirements, is also considered as biofuel. The biggest problems imposed by these conditions are directly associated with the carrying-out of the emission requirements, because when using vegetable oil as a fuel, usually increases the composition of the solid particles and nitrogen oxides in exhaust gases, that not only adversely affect the environment, but also is a serious threat to human health, and as a result trying to save the world from the global warming, human health continues to deteriorate. It is therefore necessary to carry out studies and find solutions to reduce harmful emissions from diesel engines when using vegetable oil fuel. For more qualitative and effective research on vegetable oil fuel emissions, the equipment for vegetable oil fuel testing has been developed. This equipment allows fast checking of theoretically proposed hypotheses and detailed calculations for vegetable oil fuel combustion processes and objective data acquisition. The equipment consists of the classic diesel engine adapted for work with vegetable oil and is equipped with several high-precision devices to get and store the measuring data. During pilot tests the optimal measuring modes (engine rotation frequencies, number and duration of repetitions) for further research are estimated.
اظهر المزيد [+] اقل [-]The use of black-box modelling in bioprocess scale-up
2011
Mednis, M., Latvia Univ. of Agriculture, Jelgava (Latvia)
Computer models of bioprocesses have become an essential tool in biotechnology. This paper describes various bioprocess scaleup releated problems. The problems at different scales are explained. In this paper the use of computer model in E.coli fermentation scale-up from shake flask to laboratory scale bioreactor is discussed. A black box modelling approach was used. Fermentation results have been visualized and discussed. The computer model created in Matlab environment was used for bioprocess behaviour prediction. Possible bioprocess scale-up software improvements and bioprocess optimization are discussed.
اظهر المزيد [+] اقل [-]An agent-based hybrid intrusion detection system
2011
Paulins, N., Latvia Univ. of Agriculture, Jelgava (Latvia)
Intrusion Detection Systems is defined as a component that analyses system and user operations in computer and network system to protect it from possible intrusions. Current intrusion detection technologies have several shortcomings. Applying mobile agents to intrusion detection design is step forward on better intrusion detection. Mobile-agent based distributed intrusion detection systems are very promising for the following reasons: reduction of data movement, load-balance, flexibility, fault-tolerance, detection of distributed attacks. Hybrid intrusion detection is defined by both the method used to detect attacks and the placement of the system on the network. Intrusion detection system may perform either misuse detection or anomaly detection and may be deployed as network-based or host-based system. This paper proposes to distribute classical intrusion detection model with mobile agents making an agent-based hybrid intrusion detection system. The proposed model can help detect simple intrusions in early stage and also distributed intrusions by monitoring several subjects installed on network. Main benefit from mobile agents in such system is ability to generate separate services for specific tasks and analyze unknown user patterns with several methods of artificial intelligence.
اظهر المزيد [+] اقل [-]Low-cost electrical energy monitoring method with wireless ICT
2011
Apse-Apsitis, P., Riga Technical Univ. (Latvia) | Avotins, A., Riga Technical Univ. (Latvia | Ribickis, L., Riga Technical Univ. (Latvia
The electricity consuming end-user profile has changed in latest years, due to development of new electrical devices with increased functionality and complexity. Also increasing number of electricity consuming equipment that is available to end-user, makes very hard to identify real electricity consumption of each device. The existing wall plug digital power meters are too expensive for long-term power metering of each consuming device. The article describes a different approach of power metering system that lowers the costs and price of needed metering equipment. A new concept of low-cost energy monitoring system with wireless communication is developed.
اظهر المزيد [+] اقل [-]Pseudomonas syringae as important pathogen of fruit trees with emphasis on plum and cherry
2014
Konavko, D., Latvia Univ. of Agriculture, Jelgava (Latvia);Latvia State Inst. of Fruit-Growing, Dobele (Latvia) | Morocko-Bicevska, I., Latvia State Inst. of Fruit-Growing, Dobele (Latvia) | Bankina, B., Latvia Univ. of Agriculture, Jelgava (Latvia)
The aim of this article was to provide an overview on the current status of fruit tree diseases caused by Pseudomonas syringae, their importance and distribution, epidemiology and control possibilities with emphasis on plums and cherry. The plant diseases caused by Pseudomonas syringae are economically important and occur worldwide on large diversity of plants. On stone fruits, diseases caused by different pathovars of Pseudomonas syringae are economically important in major fruit growing regions. The severity of damages and economic importance depends on the geographical region, host plant species and pathovar of P. syringae involved in the disease. Bacterial canker induced by P. syringae pv. syringae on all commercially grown stone fruit species and by pv. morsprunorum predominantly on cherries and plums is considered to be the most serious one. Bacterial decline caused by P. syringae pv. persicae is severe on nectarine and peach. Despite the wide spread and economic importance in the most stone fruit growing areas the diseases caused by Pseudomonas syringae in some areas, e.g. Baltic States, are poorly studied, and the data on distribution and pathovars involved in the diseases observed are still missing.
اظهر المزيد [+] اقل [-]Yield maturity parameters of hybrid grapevine (Vitis sp.) cultivar ‘Zilga’
2014
Raetsep, R., Estonian Univ. of Life Sciences, Tartu (Estonia) | Karp, K., Estonian Univ. of Life Sciences, Tartu (Estonia) | Vool, E., Estonian Univ. of Life Sciences, Tartu (Estonia)
The number of grape (Vitis sp.) cultivars is increasing every year, the focus point of recent grapevine studies are heading to producing high quality fruits for producing quality wine. A field trial with cultivar ‘Zilga’ was established in 2007 at the Estonian University of Life Sciences and in 2010 in a greenhouse. ‘Zilga’ is one of the well adopted cultivars in Estonia, which has been used mostly for producing wine and grown in open field conditions. The aim of the present experiment was to find out the yield maturity parameters of cultivar ‘Zilga’ for red wine in Estonian conditions. Data was collected from the year 2011 to 2013. The bunch weight and °Brix were determined from fresh materials, but all the other biochemical parameters were determined from frozen (-20 °C) grapes. The recommended content (20 °Brix) of soluble solids was not obtained in open field conditions, but reached to 24.1 °Brix in greenhouse conditions in 2013. Titratable acids content was higher than recommended values, ranging from 1.4 to 1.6 mg 100 gE-1 in open field and showing the lowest content (1.2 mg 100 gE-1) in greenhouse conditions. Maturity index values ranged from 117 to 224, and the optimum was reached in two years from three. The highest total phenolics content, 293 mg 100 gE-1 was obtained in 2011, while anthocyanin content was significantly increased in 2013.
اظهر المزيد [+] اقل [-]Fertilization value of early red clover, Washington lup and Crimson clover as green manure crops
2014
Bender, A., Estonian Crop Research Inst., Jogeva, Jogeva vad. (Estonia) | Tamm, S., Estonian Crop Research Inst., Jogeva, Jogeva vad. (Estonia)
Field trials were carried out at Jõgeva Plant Breeding Institute in 2008 – 2011 to identify the possibilities of using early red clover (Trifolium pratense L.) ‘Jõgeva 433’ (diploid), Washington lupine (Lupinus polyphyllus Lind.) ‘Lupi’ and crimson clover (Trifolium incarnatum L.) as green manure. Fresh material of the above species was ploughed into the soil in autumn of the sowing year. Fertilizer value was quantified through yield and grain quality of spring wheat ‘Vinjett’ and barley ‘Inari’. The composition and amount of ploughed biomass were recorded. By the time of ploughing, Washington lupine had produced the most abundant biomass. >From studied species crimson clover had the lowest fertilizer value – only by 6–7% extra yield of spring wheat in the following year. Crimson clover had no residual effect of fertilization in the second year. The fertilizer values of red clover and Washington lupine were approximately equal. Their effect on yield increase of spring wheat and barley lasted for three years, on grain quality for two years. Red clover, ploughed into the soil in the year of sowing, resulted in maximum spring wheat yield increase of 23.9%, compared with N 0 treatments; that of Washington lupine was 21.3%. The residual positive effect in the second year quantified as barley production increased by 6.2% in Washington lupine and 7.9% in red clover. The yield increase in the third year was 3.9% and 12.1%, respectively. Green manure increased the contents of crude protein and gluten in spring wheat and crude protein content in barley.
اظهر المزيد [+] اقل [-]The efficiency of biogas digestate on grassland compared to mineral fertilizer and cattle slurry
2014
Tampere, M., Estonian Univ. of Life Sciences, Tartu (Estonia) | Viiralt, R., Estonian Univ. of Life Sciences, Tartu (Estonia)
Biogas production from organic wastes is gaining popularity, especially in agriculture, which produces high quantities of organic wastes suitable for anaerobic digestion. Digestate is the valuable by-product of the biogas production that is considered as a valuable fertilizer. The objectives of the experiment conducted from 2012 to 2013 at the Estonian University of Life Sciences were to compare the impact of biogas digestate, undigested (raw) cattle slurry, and inorganic nitrogen fertilizer on grass yield and to assess the fertilizer value of digestate produced from different feedstock. Fertilizers were applied to the grassland rich in low grasses by broadcasting in quantities according to the nitrogen rate of 180 kg haE-1 in three split applications. The application rate of organic fertilizers was calculated based on NH4 -N content. Grassland yield was determined on four treatments: (i) control (no fertilizer was applied), (ii) mineral N-fertilizer (NH4 NO3), (iii) cattle slurry and (iv) cattle slurry digestate. Grass yield was measured three times during the growing period. Our research showed that digestate when applied based on its NH4 -N content is effective fertilizer in grassland. It could be used as a substitute for mineral-N fertilizer, but its efficiency is slightly lower when compared to cattle slurry, due to its lower application amount resulting in lower nutrient and organic matter amount applied to the grassland. Co-digestion of cattle slurry with solid manure, hay and silage does not decrease digestate fertilizer value in grassland, because the addition of other substrate increases digestate DM content.
اظهر المزيد [+] اقل [-]Effect of farm size on the productivity and longevity of Latvian brown cows
2014
Cielava, L., Latvia Univ. of Agriculture, Jelgava (Latvia);Latvian Rural Advisory and Training Centre, Ozolnieki parish, Ozolnieki municipality (Latvia) | Jonkus, D., Latvia Univ. of Agriculture, Jelgava (Latvia) | Paura, L., Latvia Univ. of Agriculture, Jelgava (Latvia)
One of most important traits in dairy farming is cow (Bos primigenius taurus) longevity. In last few years the length of productive life in Latvian dairy cow population significantly decreased. Cow longevity depends on a large amount of genetic and non-genetic factors. Data from 1037 excluded Latvian brown (LB) breed cows were included in the analysis. Cows were born in the period from the year 2002 to 2006 and a farm size was 9 – 163 cows per farm. Farms were dislocated in all main regions of Latvia. Average life length of cows excluded from the herd was 2463.0 days in small farms, 2234.6 days in medium size farms and 2089.5 days in large farms. Cows’ productivity in one life day in small farms was 5.9 kg energy corrected milk (ECM), in medium size farms 6.2 kg ECM and in large farms 6.5 kg ECM. Large farm cows had longer life length in days (p is less than 0.05), but higher productivity in one productive day (p is less than 0.05) and productivity in one life day.
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