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Результаты 41-50 из 98
Intercultural communicative competence
2010
Araja, A., Latvia Univ. of Agriculture, Jelgava (Latvia) | Aizsila, A., University of Latvia, Riga (Latvia)
The aim of the study is to investigate and analyse the Model of Intercultural Communicative Competence in the Primary Schools. The investigation is based on the theoretical approach – scientific literature analysis of Intercultural Communicative Competence is done. According to that the Model of Intercultural Communicative Competence and the Competence assessment in the Primary Schools' Foreign Language (English) Lessons (for students aged 12-14) has been made. The Model of Intercultural Communicative Competence comprises Linguistic competence, Sociolinguistic competence, Discourse competence, and Intercultural competence. The developmental model of intercultural sensitivity consists of Ethnocentric stage (denial, defence, minimization), and Ethnorelative stage (acceptance, adaptation, integration). Intercultural methodology for teaching foreign languages includes Intercultural comparison, Intercultural didactics, and Intercultural Language awareness. Assessment of Intercultural communication competence shows culture understanding: empathy toward other (target) culture, ability to observe and analyse a culture, ability to communicate in the foreign (target) language.
Показать больше [+] Меньше [-]Effect of differences in soil moisture on winter wheat yield
2010
Dinaburga, G., Latvia Univ. of Agriculture, Jelgava (Latvia) | Lapins, D., Latvia Univ. of Agriculture, Jelgava (Latvia) | Kopmanis, J., Latvia Univ. of Agriculture, Jelgava (Latvia)
It is important to define which of the plant growth factors determines the yield level. During recent years in Latvia, in most cases it was moisture. Grain yield level mostly depends on meteorological conditions during the tillering stage. Plants do not utilize all water from precipitation. Rain water efficacy depends on soil granulometric composition and content of humus. Humus content could be considered as regulated factor. Important is also distribution of precipitation during the vegetation period as well as run-off of rain water which depends on micro-relief, soil tillage type, and direction in accordance with the slope gradient. It is very important for cereal growing in what conditions tillering is done, because during that time productive stems as well as ear sprouts are formed. The aim of this research was to determine the effect of soil moisture on the growth and development of winter wheat Triticum aestivum L. Field trials were carried out during 2005-2007 in Kurpnieki field at the Research and Study farm „Vecauce” of the Latvia University of Agriculture. A total of 47 points (distributed as a grid of 50×50 m) were selected for sampling in the winter wheat field. In both experimental years, the increasing soil moisture in spring had a significant positive effect on the flag leaf area, which, in its turn, increased also the level of grain yield. Partial correlation analysis showed that exclusion of organic matter content and altitude above the sea level as factors, changes soil moisture at different layers of the soil insignificantly.
Показать больше [+] Меньше [-]Impact of some agroecological factors on winter oilseed rape (Brassica napus L.) plant density
2010
Balodis, O., Latvia Univ. of Agriculture, Jelgava (Latvia) | Gaile, Z., Latvia Univ. of Agriculture, Jelgava (Latvia)
Winter rape (Brassica napus L.) significance among field crops is unchangeable for last decade in Latvia. Rape plant development in autumn, plant wintering and plant yielding is partly influenced by plant density. The aim of our research, started in autumn 2007 in the Research and Study farm ''Vecauce'', was to investigate the influence of agro-ecological factors (sowing date, sowing rate and fungicide (as growth regulator in autumn) application) on two type (line and F1) winter rape varieties' plant density in autumn, in spring and at harvesting. Plant density in autumn, in spring and during harvesting was determined also by meteorological parameters as air temperature and precipitation. Oilseed rape field germination was observed from 84% sown on 1st of August in 2007 till 67% sown on 1st of August in 2008. A significant impact (p is less than 0.05) of the sowing rate was noted for plant winter hardiness (in points) for variety 'Californium' in both years: 2008 and 2009. Fungicide application effect on plant survival during winter was observed for treatments with greater plants density. A very little average plant number decrease per square m during summer growth period was noted for all treatments in both years - within 1 to 4% in some cases. The tendency was observed that final plant density at harvest if greater sowing rates had been used, was never high on average for 'Californium' from 75 plants per 1 square m (120 germinable seeds per square m) to 60 plants per 1 square m (100 germinable seeds per square m) in 2009. Correlations between plant density at harvest time and seed yield were found.
Показать больше [+] Меньше [-]Effect of silaging on chemical composition of maize substrate for biogas production
2010
Bartusevics, J., Latvia Univ. of Agriculture, Jelgava (Latvia) | Gaile, Z., Latvia Univ. of Agriculture, Jelgava (Latvia)
Maize (Zea mays L.) is one of the agricultural plants that is suitable substrate for biogas production. Fresh as well as ensiled maize can be used as biogas substrate. Practically, mainly maize silage is used because fresh maize is available only for short term during the vegetative period. The paper is aimed to determine the impact of ensiling on substrate composition of maize hybrids. A field trial was carried out in the Research and Study farm ''Vecauce'' of the Latvia University of Agriculture (LLU) in 2008 and 2009. Ten (in 2008) to eleven (2009) maize hybrids with different maturity rating according to FAO numbers (FAO 180 – 340) were harvested at three different times beginning on 5 September at fourteen-day intervals. Chopped maize samples of 1-3 kg were ensiled in plastic silos. Samples of fresh and ensiled (for at least 90 days) maize were analyzed detecting 14 parameters in the Scientific Laboratory of Agronomy Research of LLU using standard methods. Our results showed that ensilaging influence on organic dry matter and hemi-cellulose content was not substantial. High (p is less than 0.05) correlation between organic dry matter content of fresh and ensiled samples was noted. The crude protein, crude fibre, ash and cellulose concentration was greater in the ensiled samples if compared with fresh maize samples in 2008 and 2009. After ensilaging process neutral detergent fibre (NDF) concentration was higher compared with fresh samples in 2009 but lower in 2008.
Показать больше [+] Меньше [-]Nitrogen removal with apple-tree fruits
2010
Surikova, V., Latvia Univ. of Agriculture, Jelgava (Latvia) | Karklins, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
The investigation was done at the Latvia State Institute of Fruit-Growing in Dobele in 2009, on the basis of an established field experiment planted in 1997 with apple (Malus domestica Borh.) cultivar 'Melba' (rootstock B9) trees spaced at 1.5 × 4 m distances. Three different treatments of soil moisture management were compared: control, sawdust mulch and fertigation. Soil of the experimental plot was Haplic Luvisol (Hypereutric), sandy loam, interspaced with Cutanic Luvisol, sandy loam. Organic matter – 25 g kgE-1, soil reaction pH – 6.5. Plant available P was 130.9, K – 157.7, and Mg – 102.2 mg kgE-1. The aim of the investigation was to determine nitrogen removal with fruit yield taking into consideration the used soil moisture regulation method – sawdust mulch or fertigation. The applied soil moisture regulation methods (mulch and fertigation) had significant influence on the content of dry matter in apple fruits (p is less than 0.05). The highest content of dry matter was found in the control treatment. A significantly higher nitrogen concentration (47 g kgE-1) in apple dry matter was in the control treatment, whereas in mulch and fertigation treatments nitrogen concentrations were lower (36 and 42 g kgE-1). The highest nitrogen concentration in dry matter was found in fruits with the biggest mass (r=0.61). A negative significant (p is less than 0.05) correlation was found between nitrogen concentration and trunk diameter (r=–0.85), and between nitrogen concentration and yield (r=–0.84). Removal of N was 24.4 kg haE-1 in the control, 22.3 kg haE-1 in the mulch, and 25.0 kg haE-1 in the fertigation treatment.
Показать больше [+] Меньше [-]Analysis of kappa-casein (CSN3) alleles in Latvian Brown and Latvian Blue breed populations
2010
Smiltina, D., Latvia Univ. of Agriculture, Jelgava (Latvia) | Grislis, Z., Latvia Univ. of Agriculture, Jelgava (Latvia)
Genotypes of CSN3 gene were detected in 71 individuals of Latvian Blue breed and in 30 individuals of Latvian Brown breed using a PCR-RFLP method. Animals were chosen at random from each heard. This study investigated the alleles A and B of CSN3 gene, while determining the allele and genotype frequencies and Hardy-Weinberg equilibrium proportions in both populations. The results showed that in our analyzed samples from 71 Latvian Blue breed only 7 animals (10%) had the genotype BB, and in analyzed samples from 30 Latvian Brown breed only 3 had the genotype BB (10%). Frequencies of CSN3 genotypes AA, AB, and BB correspond to Hardy-Weinberg equilibrium proportions and populations in genetic equilibrium. A wide variation in the B allele frequency among Latvian Blue and Latvian Brown breeds was found suggesting that molecular selection for animals carrying the allele B of CSN3 could impact breeding programs for dairy production in Latvia.
Показать больше [+] Меньше [-]Use of heat exchangers in ventilation systems of pigsties in dependence on outside air temperature
2010
Zagorska, V., Latvia Univ. of Agriculture, Jelgava (Latvia) | Jesko, Z., Latvia Univ. of Agriculture, Jelgava (Latvia) | Ilsters, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
To raise the level of energy efficiency of the ventilation systems of pigsties it is useful to introduce heat exchangers. A heat exchanger is a device built for efficient heat transfer from one medium to another. In the case when a heat exchanger is used in the ventilation systems of premises of pigsties, clean and cold air (in the autumn-winter period) gets amount of heat energy from unclean but warm inside air. Respiration of pigs and the processes occurring on the surface of manure cause the generation of carbon dioxide and ammonia, which are considered harmful gases not only for people and animals but also for the equipment, high relative humidity that occurs also during respiration of pigs influences working conditions as well. The article deals with experimental results obtained from the experiments about plate counter-flow heat exchanger models with plastic cellular boards (HE PVC) and plastic plates (WVT-120K) as heat transfer surfaces. Operational parameters describing the energy efficiency of heat exchangers were calculated – power of recovered heat energy (kW), heat transfer coefficient (WmE-2 deg CE-1), and coefficient of efficiency by recovered heat. Due to better operational parameters of experimental recuperative outflow heat exchanger (HE PVC) simulation and analysis of its exploitation during 4 seasons (December/January) depending on outside air temperature in the article are made as well. The possibility of development of ESA heat exchanger construction with built-in tubular electrical heater to preheat outside air (at outside air temperatures below -15 deg C) has been carried out in the research.
Показать больше [+] Меньше [-]Emission reduction potential of using biofuels
2010
Pirs, V., Latvia Univ. of Agriculture, Jelgava (Latvia) | Dukulis, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
One of the primary reasons for expanding the production and use of biofuels is the potential environmental benefit that can be obtained from replacing fossil fuels with fuels derived from renewable biomass resources. This investigation examines the impact of biofuels on the environment directly from the practical view point analysing how the internal combustion engine emission concentration changes using the most common first-generation biofuels in Latvia – biodiesel, rapeseed oil and bioethanol. Laboratory experiments were performed on a chassis dynamometer Mustang MD1750, but the content of exhaust gases components was determined by the AV L SESAM FTIR measurement system. Investigation shows that the trends of different exhaust gas component changes, which would be the same for all investigated fuels, don't exist, i.e., each vehicle and biofuel type or blend is particular and has to be analysed separately. In comparison with fossil diesel, running the car VW Golf on rapeseed oil the average reduction of NOx was 10%, but SO2 – 59%. The CO, CO2, unburned hydrocarbon and mechanical particle emissions were higher. Running the car Opel Vectra on biodiesel the amount of NOx in comparison with fossil diesel increased in average by about 12%, the amount of mechanical particles and unburned hydrocarbons decreased quite significantly, but just a small increase of CO and SO2 was observed. Testing the car VW Passat on gasoline-bioethanol blends increase of the bioethanol content in the fuel blend increased also the NOx content in exhaust gases, but the content of CO, CO2 and NH3 decreased.
Показать больше [+] Меньше [-]Comparison of spectrophotometric methods for assessment of oxidation of milk fat
2010
Antone, U., Latvia Univ. of Agriculture, Jelgava (Latvia);Latvia Univ. of Agriculture, Sigulda (Latvia). Research Inst. of Biotechnology and Veterinary Medicine Sigra | Sterna, V., Latvia Univ. of Agriculture, Sigulda (Latvia). Research Inst. of Biotechnology and Veterinary Medicine Sigra | Zagorska, J., Latvia Univ. of Agriculture, Jelgava (Latvia)
Three spectrophotometric methods were compared for the assessment of milk fat oxidation: the AOCS (American Oil Chemists' Society) 2-thiobarbituric acid (TBA) value direct method, the TBA method of Aristova, and the modified method for the estimation of total carbonyl compounds in oils of Endo et al. Two cow milk fat samples – a fresh fat, obtained from fresh milk, and a rancid fat, obtained from a rancid commercial butter by means of high-speed centrifugation (15.871 × g, 30 minutes at 40 deg C) – were analyzed several times in a 22-day period after sample preparation. A positive linear correlation between absorbance and storage time was established in all used methods. The method of Aristova is appropriate for exact determination of oxidation products. This method had rather good R2 value (0.85) of the fresh fat sample results; however, the coefficient of variation (45.78%) showed rather large deviations between parallel analyses. The methods of AOCS and Endo et al. can be used for the assessment of the dynamics of fat oxidation by reporting absorbance values from the assay directly. By these methods rather high R2 values (0.86, 0.93) of the fresh fat sample results were obtained; the coefficients of variation also were satisfactory (10.13%, 11.12%). The last two methods are cheaper and require smaller sample amounts (less than 0.2 g), while the method of AOCS is the most time-consuming method.
Показать больше [+] Меньше [-]Antiradical activity of rye bread during baking
2010
Ozolina, V., Latvia Univ. of Agriculture, Jelgava (Latvia) | Kunkulberga, D., Latvia Univ. of Agriculture, Jelgava (Latvia)
Nowadays one of most urgent problems is the production of healthy food which ensures normal maintenance of the human body. Rye bread is one of the bases of wholesome food. Every year scientists in Europe and other countries carry out investigations on the nutritional impact of processing rye. Interesting questions arise regarding changes in the biologically active compounds in rye bread as a result of processed. Connate antiradical activity (ARA) of rye bread affects free radicals by scavenging or donating electrons, which suggests that the ARA of rye bread averts attacks of free radicals on human cells. Therefore it is important to use antioxidants containing products with antiradical activity in human diets. The aim of this study was to analyse the impact of baking processing on rye bread antiradical activity. The object of the study was Latvian traditional rye bread baked in a commercial bakery, made with scald, and baked in a clay-floor firewood oven. The antiradical activity of rye bread crumb and crust was measured by using free radical 2.2-diphenyl-1-picrylhydrazyl (DPPH). It was concluded in the research that rye flour type 1740 has antiradical activity by scavenging 67 μmol·100gE-1 DM of the stable free radical DPPH, which is 13% more than the dough antiradical activity of the same flour. The antiradical activity of the crust is 49.6% more than the antiradical activity of the crumb. Baking time has no significant impact on changes in the antiradical activity of rye bread crumb.
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