خيارات البحث
النتائج 21 - 30 من 70
Business cycles of Baltic countries and their main trading partners
2005
Freimane, R.(Latvia Univ. of Agriculture, Jelgava (Latvia))E-mail:Ilona.Ozolina@hansabanka.lv
The aim of the paper is to analyze relationship between international trade and the correlation of the business cycles between Baltic countries and their main trading partners. Two univariate methods are used to extract cyclical components in the time series: exponential smoothing procedure the Hodrick-Prescott filter and unobserved components method. A simple regression model proves the hypothesis that trade intensity has led to business cycle synchronization. The main conclusion is that there exists a strong correlation between the business cycles of the Baltic countries. However, the economic cycle of Baltic countries is different from that of their main trading partners in EU. According to Optimum Currency Area theory, these results cast doubts on the usefulness of adopting the euro in the Baltic countries in the near future. On the other hand, recently the deepening of economic integration has led to make intense trade between the Baltic countries and the EU, which may eventually imply more synchronised cycles in the future.
اظهر المزيد [+] اقل [-]The investigation on the evaluation of drained land
2005
Bastiene, N.(Lithuanian Univ. of Agriculture, Kaunas (Lithuania). Water Management Inst.)E-mail:vegelyte@delfi.lt | Saulys, V.(Lithuanian Univ. of Agriculture, Kaunas (Lithuania). Water Management Inst.)E-mail:vegelyte@delfi.lt
Agricultural development based on the laws of market economy enhances a change in the point of view on land as real property and search for optimal variants of its possible usage. As a large part of all agricultural land has been drained, efficient functioning of water regime regulation means is one of the essential factors determining the possibilities of land use as well as its value. Land areas where land reclamation structures are in good condition and do not needs to be repaired or reconstructed will always be of higher demand under the conditions of market economy. Present prices of agricultural land do not show the value of land reclamation systems. Therefore a complex land assessment is needed in respect of the present condition of land reclamation structures, its age and probabilities of failures.
اظهر المزيد [+] اقل [-]Beta-glucan in hydrolysed soluble and insoluble oat fractions
2005
Gramatina, I.(Latvia Univ. of Agriculture, Jelgava (Latvia))E-mail:blijaa@cs.llu.lv | Kreicbergs, V.(Latvia Univ. of Agriculture, Jelgava (Latvia))E-mail:blijaa@cs.llu.lv
Oats contain more beta-glucan (2-7%) than other croppers. Beta-glucan is the most essential water-soluble dietary fibre. It lowers cholesterine level in blood as well as stimulates elimination of carcinogens from the body. In order to enlarge possibilities of use of oats in a diet, they can be separated in water-soluble and insoluble fractions. The aim of the present study is to determine the amount of beta-glucan in hydrolysed oat soluble and insoluble fractions. Gelatinized, hydrolysed and steeped oatmeal prior to hydrolyse, which was separated in water-soluble and insoluble fractions, was used in experiments. Not more than 6% of gelatinized (non-hydrolysed) oatmeal dry matter dissolved in water. The outcome of fermentative hydrolysed dry matter of water-soluble oatmeal was 40-52%. The content of beta-glucan in soluble and insoluble oatmeal fraction was determined by using McClearly method. The content of beta-glucan fraction of gelatinized oatmeal decreased for 78% in comparison to the content of beta-glucan in oatmeal used in the experiments. The content of beta-glucan in the soluble fraction of hydrolysed oatmeal decreased for 8.1% to 9.2%, and increased for 35-42% in the insoluble fraction if compared with the content of beta-glucan in oatmeal.
اظهر المزيد [+] اقل [-]The comparison of chemical pollution between organic and conventional milk
2005
Zagorska, J.(Latvia Univ. of Agriculture, Jelgava (Latvia)) | Ciprovica, I.(Latvia Univ. of Agriculture, Jelgava (Latvia))E-mail:inga.ciprovica@llu.lv
In Latvia have not been carried out comparable studies regarding chemical pollution in organic and conventional milk, therefore the aim of the present study was to investigate the level of contamination in organic and conventional milk samples by heavy metals and aflatoxin M1. A total of 9 organic bulk milk and 9 conventional bulk milk samples were collected from different regions of Latvia. The content of lead, cadmium, copper, iron, and zinc were detected by flame technique, using atomic absorption spectrophotometer (AAS). The level of aflatoxin M, in organic and conventional milk samples was determined by high-performance liquid chromatography. The means of lead concentration in organic and conventional samples were 0.024 and 0.31 mg kgE-1 wet weight that exceed the permissible level for such a product. The cadmium content in organic and conventional milk samples is very low and fairly constant in all types of milk. The legally accepted upper limits of iron, copper and zinc are not exceeded by any analyzed milk sample, not even from conventional bulk milk. The study including heavy metals and aflatoxin M1 in a range of organic and conventional milk samples found no significant differences between organic and conventional milk (p=0.05) in the level of aflatoxin M1 and the heavy metals.
اظهر المزيد [+] اقل [-]The dynamics of vitamin C and total carotenes content in pasteurized sea-buckthorn juice
2005
Seglina, D.(Dobele Horticultural Plant Breeding Experimental Station (Latvia))E-mail:seglina@ddsis.lv | Karklina, D.(Latvia Univ. of Agriculture, Jelgava (Latvia))E-mail:kada@cs.llu.lv
To select new sea-buckthorn hybrids and forms with increased content of biologically active substances, breeding work with sea-buckthorn hybrid seedlings is carried out in Latvia. The aim of this research was to study the vitamin C and total carotenes content in sea-buckthorn juice and its stability at different pasteurization temperatures with several durations. For study 6 sea buckthorn hybrids from 3 hybrid families were used. Vitamin C and total carotenes were determined in freshly made juice and with pasteurization at 65 deg C, 75 deg C and 85 deg C for 30, 20 and 10 minutes respectively. After processing the data obtained, it was found that vitamin C and total carotene content did not alter significantly depending on pasteurization temperature and duration. For further research 3-sea-buckthorn hybrids have been selected with the highest content of vitamin C and total carotenes.
اظهر المزيد [+] اقل [-]Dynamics of peroxide value in flavoured rapeseed oil
2005
Kruma, Z.(Latvia Univ. of Agriculture, Jelgava (Latvia))E-mail:zanda.kruma@llu.lv | Kreicbergs, V.(Latvia Univ. of Agriculture, Jelgava (Latvia)) | Karklina, D.(Latvia Univ. of Agriculture, Jelgava (Latvia))E-mail:kada@cs.llu.lv
Spices are used to season food products. Investigations were carried out to determine dynamics of primary oxidation products in flavoured rapeseed oil depending on used spice, its concetration, storage duration, and sample preparing method. The oil was flavoured with winter savoury Satureja Montana L., hyssop Hyssopus officinalis L., and marjoram Oreganum vulgare L. Results showed that dynamics of peroxide value in flavoured oils were influenced significantly (p is less than 0.05) by all investigated factors - used spice, its concentration, storage duration, sample preparing method, and interaction of these factors, too. Heating of oil in particular cases caused unusual, hard explainable dynamics of peroxide value. It is necessary to investigate optimal conditions of flavouring of oils and components of spices which can influence oxidation of flavoured oils.
اظهر المزيد [+] اقل [-]Immunoglobulins and lactoferrin concentration in milk and bacteria causing subclinical mastitis in dairy cows
2005
Kocina, I.(Latvia Univ. of Agriculture, Jelgava (Latvia))E-mail:iveta.kocina@pvd.gov.lv | Antane, V.(Latvia Univ. of Agriculture, Jelgava (Latvia)) | Lusis, I.(Latvia Univ. of Agriculture, Jelgava (Latvia))
Natural defence mechanisms of the mammary gland tissues play a vital role in protecting the gland from infections. The progress of mammary infection depends on the ability of bacterial pathogens to adapt to milk and udder tissues, and on the various virulence factors they activate, as well as on the cow's response. The levels of immunoglobulins (lg) and lactoferrin (Lf) concentration in the milk from dairy cows with and without subclinical mastitis were determined. In this investigation it was stated that 82.5% of samples were negative, but 17.5% of samples were positive for pathogens. Cows had subclinical mastitis caused by Coagulase negative staphylococci observed in 48.60%, Streptococcus uberis - 32.10%, Staphylococcus aureus - 18.90% of cases in milk samples. There were no significant differences between all classes of immunoglobulins concentration in the milk without pathogens and with pathogens. The lactoferrin concentration was significantly increased for 40.33% in the milk with pathogens.
اظهر المزيد [+] اقل [-]Distinguishing between the effect of seed material and forest type on Scots pine stand productivity
2005
Jansons, A.(Latvian Forestry Research Inst. Silava, Salaspils (Latvia))E-mail:arisjansons@navigator.lv
Due to large diversity of site conditions suitable for Scots pine growth in Latvia, it is important to evaluate their influence on growth and survival of particular Scots pine families. To do so, open pollinated progenies from phenotypically selected plus trees of 35 at the age of 32 years have been evaluated in 2 forest types (Cladinosa-callunosa and Hylocomyosa). Investigation revealed that forest type and family influence had a great significance to height, diameter at breast height, and diameter of thickest branch up to 2 meters' height (alpha is less than 0.001), but clone influence had lower significance (alpha=0.008). Proportion of influence to height growth caused by tree family was 70% at the age of 6 years and 17% at the age of 32 years. Proportion of influence on survival caused by tree family was 57% and 44% respectively. The corresponding influence of forest type was 12% and 28% to height, 15% and 39% to survival. Diameter at breast height at the age of 32 years was equally influenced by forest type and family (~11%). Equal breeding effect - but not with the same families - can be reached both in fertile and poor soils. In group (20%) selection this effect was ~8% for height, 11% for diameter, and 30% for survival; in individual selection ~10% for height, and ~17% for diameter.
اظهر المزيد [+] اقل [-]Impact of the working width of the plough body on the tillage efficiency
2005
Rucins, A.(Latvia Univ. of Agriculture, Jelgava (Latvia))E-mail:arucins@delfi.lv | Vilde, A.(Latvia Univ. of Agriculture, Jelgava (Latvia))E-mail:vilde@delfi.lv
Theoretical and experimental investigations are carried out to estimating the impact of the plough body working width on its specific draft resistance, as well as the ploughing efficiency. By using analytical correlations derived as a result of theoretical research, a computer algorithm has been worked out for simulating the functions of the plough body and the forces exerted by soil upon the operating parts, as well as its draft resistance. Specific draft resistance of the plough body, energy consumption, as well as labour efficiency and ploughing costs depend considerably on the working width of the body. By increasing it, the energy capacity, specific fuel consumption and expenditure decrease, but labour efficiency increases.
اظهر المزيد [+] اقل [-]System modelling of the grain drying process
2005
Arhipovs, S.(Latvia Univ. of Agriculture, Jelgava (Latvia))E-mail:sergejs.arhipovs@llu.lv
One of the prior trends of research is the problem studies of power economy of technological processes and quality automatic control. Though the theory of grain drying process has been developed profoundly, still there are problems in its implementation. The developed analytical and simulation models of grain drying are difficult to implement into practice because they do not contain all the factors, which influence the real grain drying process or they cannot be solved. The developed models enable to assess only the essentiality of factors and/or the fundamental basics of the process. In order to ensure the effective and user-friendly grain drying process, it is indispensable to develop the control methodology using system modelling approach. The present paper deals with the system approach to heat and mass transfer problem and the testing of the basic hypothesis of the diffusion theory about the normal distribution of particles in the diffusive environment.
اظهر المزيد [+] اقل [-]