خيارات البحث
النتائج 1431 - 1440 من 2,098
Non-starter lactic acid bacteria in raw milk, thermally treated milk and Swiss type cheese
2016
Bluma, A., Latvia Univ. of Agriculture, Jelgava (Latvia) | Ciprovica, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
The diversity of non-starter lactic acid bacteria in raw, pasteurised milk and maturated Swiss type cheese was tested. The aim of the present study was to analyse the concentrations and representatives of non-starter lactic acid bacteria in raw milk and to evaluate the changes of their concentrations and representatives during pasteurisation of cheese milk and Swiss-type cheese production. The analysis carried out in the study showed a variation in the microbial composition and quantity of raw milk. The most frequently isolated lactobacilli were found at low level in raw milk (mean 27.5×104 CFU mLE-1) and the most frequently identified species were Lactobacillus brevis and Lactobacillus paracasei. The microflora of raw and pasteurised milk is similar analysing lactic acid bacteria representatives in the samples. Lactobacillus brevis and Lactobacillus paracasei were detected in the same samples in raw milk, pasteurised milk and maturated cheese. Our study showed that lactic acid bacteria concentration was quite low in pasteurised milk (1-12 CFU mLE-1), but they grow rapidly in cheese during ripening reaching 1.1-1.8*106 CFU gE-1. The present study has shown that NSLAB in Swiss-type cheese mainly derive from raw milk, and only a few strains survive the processing conditions and grow during ripening.
اظهر المزيد [+] اقل [-]Investigation of immature wheat grain chemical composition
2016
Petrovska-Avramenko, N., Latvia Univ. of Agriculture, Jelgava (Latvia) | Karklina, D., Latvia Univ. of Agriculture, Jelgava (Latvia) | Gedrovica, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
The present study provides research in content of protein, starch, sugars and concentration of B group vitamins (thiamine, riboflavin, pyridoxine and niacin) in immature wheat (Triticum aestivum L.) compared to mature wheat kernels. The content of protein, starch was determined in kernels using Infratec1241 Grain Analyzer (Sweden), content of sugars was analysed by high- efficiency liquid chromatography HPLC (Shimadzu, Japan). The concentrations of vitamins were determined by high-efficiency liquid chromatography for vitamins B1, B2, B3, B6. Obtained results suggested that the immature wheat kernels obtained in milk stage showed higher contents of some compounds such as sugars and B group vitamins. The amount of all sugars presented in immature grains is higher and decreased uniformly during maturation. Therefore, immature grains are better sources of the B group vitamin that the mature grains, and therefore more nutritionally efficacious.
اظهر المزيد [+] اقل [-]Different dose inulin feeding effect on calf digestion canal state and development
2016
Arne, A., Latvia Univ. of Agriculture, Jelgava (Latvia) | Ilgaza, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
The aim of this study was to determine the influence of Jerusalem artichoke flour feeding on the general health status of calves (Bos Taurus), the animal live weight gain and digestive canal morphological development in the first four months of life, as well as to find out the optimal of three inulin doses. Jerusalem artichoke (Helianthus tuberosus) concentrate produced in Latvia contains the prebiotic – inulin. The study was performed on four groups of animals - a control group of 10 animals and three prebiotic groups, 10 animals in each group. All groups were fed the whole milk, but the PreG6 group animals were fed daily with 6 grams of prebiotic, calves PreG12 group were fed with 12g of prebiotic, but each calf in PreG24 group – 24g of prebiotic per day. CoG control animals did not receive feed supplement. Faecal mass consistence of PreG6, PreG12 groups of animals was more stable within the whole research period than CoG. We found that the control group animal weight gain on the 56th research day is statistically significantly (p is less than 0.05) lower than of those calves that received inulin as a food supplement. The highest growth rates have shown PreG12 and PreG24 group of animals, significantly (p is less than 0.05) being ahead of PreG6 group of calves, the highest average daily live weight gain was observed in PreG24 group (0.95 ± 0.093 kg).
اظهر المزيد [+] اقل [-]The efficacy of platelet-rich plasma use as a treatment for the osteoarthritis
2016
Plaksina, J., Latvia Univ. of Agriculture, Jelgava (Latvia) | Ilgazs, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
Platelet-rich plasma (PRP) is an autologous concentrated cocktail of growth factors and inflammatory mediators, and has been considered to be potentially effective for cartilage repair. Animal clinical studies suggest that PRP is a promising treatment for cartilage injuries and relieving symptoms due to its three biological properties: an anabolic effect, enhancement of cartilage regeneration and inhibition of inflammation. The aim of this article is to analyse the available evidence on the clinical application of this biological approach to animals for the injective treatment of cartilage lesions and joint degeneration, and also to support the rationale for the use of platelet concentrates and to give indications on what to expect from intra-articular injections of platelet-rich plasma (PRP) in animals. This article is a summary of analytical research papers about the use of platelet-rich plasma as a treatment for the osteoarthritis. The intra-articular injections do not just target cartilage; instead, platelet-rich plasma might influence the entire joint environment, leading to clinical improvement. Many biological variables might influence the clinical outcome and have to be studied to optimize PRP injective treatment of cartilage degeneration and osteoarthritis.
اظهر المزيد [+] اقل [-]Interrelations between the milk urea concentration and production and reproduction performance of dairy cows
2016
Sematovica, I., Latvia Univ. of Agriculture, Jelgava (Latvia) | Liepa, L., Latvia Univ. of Agriculture, Jelgava (Latvia)
The objective of the study was to investigate the correlation between the milk urea (MU), milk yield and reproductive performance using milk recording tests and the health check results. Weak to average negative correlation was found between MU and the milk yield (r = -0.44 and r = -0.34; p is greater than 0.05), milk protein (r = -0.22; p is less than 0.05) and milk freezing point (r = -0.33; p is less than 0.01). Higher milk fat was found in cow milk with MU below 30 mg dLE-1 in comparison with cow milk which had MU above 30 mg dLE-1, 4.0 ± 0.77% and 3.9 ± 0.75%, respectively. High MU fluctuations within a cow group can be observed if cows of different productivity levels are grouped together or if there are too many animals in one group. Correlations between MU and times of artificial insemination or the service period were not established, possibly due to successful veterinary measures. In conclusion we emphasize the necessity on large dairy farms to analyse MU concentration in relation to milk protein and fat concentration for individual animals and in each feeding group separately. The study was the part of the State Research Project (AgroBioRes) No. 2014.10-4/VPP-7/5; subproject VP29.
اظهر المزيد [+] اقل [-]Latvian normal height system testing using GNSS measurements
2016
Reke, I., Latvia Univ. of Agriculture, Jelgava (Latvia) | Celms, A., Latvia Univ. of Agriculture, Jelgava (Latvia) | Rusins, J., Latvia Univ. of Agriculture, Jelgava (Latvia)
After height system replacement in Latvia, there is a transformation formula for point height difference theoretical value in any place of Latvia. Performing practical Global Navigation Satellite System (GNSS) measurements and obtained data mathematical processing, there is also a possibility to calculate point height difference, in this case – practical values. There were thirteen 1st class levelling network points selected in territory of Latvia and got the theoretical and practical values of them. As the result, it is possible to compare height differences between Baltic Normal Height System 1977 and Latvian Normal Height System 2000,5. The practical and theoretical values should coincide, but just 3 of selected geodetic points the height difference comparing practical and theoretical values is close to zero and point height difference of all measured points differs in 17 cm amplitudes indicating problems with transformation formula or need to improve geoid model.
اظهر المزيد [+] اقل [-]Generation of a test reference year for Liepāja, Latvia
2016
Ruduks, M., Latvia Univ. of Agriculture, Jelgava (Latvia) | Lesinskis, A., Riga Technical Univ. (Latvia)
Actual and reliable meteorological data are necessary for building performance analysis. Since meteorological conditions vary significantly from year to year, there is a need to create a test reference year (TRY), to represent the long-term weather conditions over a year. In this paper TRY data model was generated by analysing every 3-hour weather data for a 30-year period (1984 – 2013) in Liepāja, Latvia, provided by the Latvian Environment Geology and Meteorology Centre (LEGMC). TRY model was generated according to standard LVS EN ISO 15927-4. The generated TRY contains from typical months that are included in TRY from a number of different years. The data gathered from TRY was compared with the climate data from the Latvian Cabinet of Ministers regulation No. 379, Regulations Regarding Latvian Building Code LBN 003-15. Average monthly temperature values in LBN 003-15 were lower than the TRY values that indicate on climate changes in this location. The results of this study may be used in building energy simulations and heating-cooling load calculations for selected region. TRY selection process should include the latest meteorological observations and should be periodically renewed to reflect the long-term climate change.
اظهر المزيد [+] اقل [-]Quaternary groundwater vulnerability assessment in Latvia using multivariate statistical analysis
2016
Retike, I., University of Latvia, Riga (Latvia);Latvian Environment, Geology and Meteorology Centre, Riga (Latvia) | Delina, A., University of Latvia, Riga (Latvia) | Bikse, J., University of Latvia, Riga (Latvia) | Kalvans, A., University of Latvia, Riga (Latvia) | Popovs, K., University of Latvia, Riga (Latvia) | Pipira, D., University of Latvia, Riga (Latvia);Latvian Environment, Geology and Meteorology Centre, Riga (Latvia)
Groundwater is the main drinking water source in Latvia, and Quaternary groundwater is widely used in households due to shallow occurrence. The identification of vulnerable areas is important for better water management and protection of deeper, more intensively used aquifers. The existing groundwater vulnerability map of Latvia does not take into account land use which can be an important factor affecting natural groundwater quality. Multivariate statistical methods - principal component analysis (PCA) and hierarchical cluster analysis (HCA) - were applied to identify groundwater groups with distinct water quality in Quaternary sediments in Latvia. On the basis of major ion concentrations and nitrogen compounds four distinct groundwater groups were identified. First group represents natural and most common calcium- magnesium bicarbonate water type in Latvia with low nitrate and ammonium concentrations. Samples from second and third group both reflect anthropogenic influence: diffuse agricultural contamination mostly with nitrates and/or contamination derived from artificial surfaces. Fourth group belongs to calcium bicarbonate water type and is characterised as a very young groundwater formed in sandy deposits. The results show that the highest concentrations of nitrogen compounds can be found in areas with agricultural land use or in artificial surfaces which are often classified as medium low or low vulnerability areas (mostly samples from group two and three). Meanwhile the lowest values of nitrogen compounds are present in areas where dominant land covers are forests and semi-natural areas or wetlands, and groundwater vulnerability classes are medium to high (samples from the first and fourth group).
اظهر المزيد [+] اقل [-]Surface water - groundwater interaction in the Salaca drainage basin using stable isotope analysis
2016
Babre, A., University of Latvia, Riga (Latvia) | Kalvans, A., University of Latvia, Riga (Latvia) | Popovs, K., University of Latvia, Riga (Latvia) | Delina, A., University of Latvia, Riga (Latvia) | Retike, I., University of Latvia, Riga (Latvia) | Bikse, J., University of Latvia, Riga (Latvia)
This paper presents first results of monthly water stable isotope monitoring programme covering the most important surface and groundwater types in the Salaca River basin. The aim is to characterise the isotopic values of different water types in the Salaca River basin, and test if their contribution can be identified in the Salaca river runoff. A monthly groundwater and surface water stable isotope monitoring programme was initiated in August 2015 covering the most of the important surface and groundwater types in the study region – groundwater and surface water in the raised bogs, free-surface groundwater including artificially drained agricultural lands, water emerging from the Lake Burtnieks as well as Burtnieks and Arulika confined aquifers. Preliminary results show that stable isotopes are useful tool to identify distinct water components and their evolution. However, it is needed to continue monitoring programme to draw significant conclusions.
اظهر المزيد [+] اقل [-]Ground-penetrating radar (GPR) screening in shallow Engure and Pape lagoon lakes
2016
Purmalis, O., University of Latvia, Riga (Latvia);Institute for Environmental Solutions, Riga (Latvia) | Alksnis, A., Institute for Environmental Solutions, Riga (Latvia) | Taskovs, J., Institute for Environmental Solutions, Riga (Latvia) | Burlakovs, J., University of Latvia, Riga (Latvia);Linnaeus University (Sweden). Faculty of Health and Life Sciences
Geophysical studies in mapping and screening applications are widely applied for archaeological, environmental, geological, hydrological and many other applications. Ground-penetrating radar (GPR) is one of methods from geophysical toolbox that is also called a ground-probing radar, subsurface radar, surface-penetrating radar and ‘georadar’ or impulse radar – it is a non-invasive and non-destructive technique. Pulsed electromagnetic signal is recording the reflected energy and scattering from subsurface objects. Studies were performed in former Littorina Sea lagoons that became lakes after the further Limnea Sea stage in the Baltic Sea established with comparatively lower absolute sea level that is close to present day situation. Characterization of sediments as well as full sediment core description for comparison with GPR signals were performed. Major results show that GPR as non-destructive method in combination with geological coring followed by laboratory analysis of sediment properties can be successfully used to describe layering conditions, topography and depth of shallow lakes. Although there are some limitations regarding the electromagnetic (EM) noise and similar EM properties of analysed sediments, proper treatment of data gives complementary insight thus diminishing the necessity of dense coring network establishments in analysed areas of lakes. The aim of this screening study is to analyse potential advantages of GPR use for mapping sediments and topography of sandy bottom in shallow lagoon lakes as well as pinpoint problems during field and cameral works considering electromagnetic, geological and topographical disturbances.
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