خيارات البحث
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Impact of Angiriai Hydropower Station on the ecosystem of the River Šušvė
2009
Vaikasas, S., Lithuanian Univ. of Agriculture, Kaunas (Lithuania). Water Management Inst. | Palaima, K., Lithuanian Univ. of Agriculture, Kaunas (Lithuania). Water Management Inst.
After a 16-m high dam was constructed and a 297-ha pond was arranged in the River Šušvė nearby Angiriai in 1980, the previous natural flow regime of the river has changed: 15500000 m3 of water accumulated above the dam is not discharged via a natural bed, but through two 1.5x1.5 m bottom orifices, and flood discharges (up to Q1% = 296 m3 sE-1) are directed into the lower reach through a 16-m high shaft spillway of floods. Such arrangement of the Angiriai dam ensured it to become an essential obstacle for migrating fish. In 2000, after the arrangement and operation of Angiriai hydro-electric power station, the water regime downstream the dam has been changed and new hydrological pulses as well as ecosystem biodiversity are to be adapted. Thus, the operation of Angiriai HPS on the River Šušvė generating hydroelectric power can have adverse effect on the river habitats and hydro ecological connectivity. To evaluate the effect, the eco-hydraulic water regime measurements in 2005 in a lower stretch with and without turbines operating were made. The study results showed that artificial water levels fluctuation (≈ 4 m hrE-1) induced by Angiriai hydro-electric power station as well as the discharge flowing through the bottom orifices due to high velocities (13–14 m sE-1) and temperature differences could create stressful situations for young fish in the lower bank. According to the data of soil texture of the Šušvė River, the bed armoring process is going on below the Angiriai HPS is quasistable and no impact of HPS operation is found.
اظهر المزيد [+] اقل [-]Comparative study of breeding bulls daughters milk quality indicators
2010
Dujina, I., Latvia Univ. of Agriculture, Jelgava (Latvia) | Jemeljanovs, A., Latvia Univ. of Agriculture, Jelgava (Latvia);Latvia Univ. of Agriculture, Sigulda (Latvia). Research Inst. of Biotechnology and Veterinary Medicine Sigra | Konosonoka, I.H., Latvia Univ. of Agriculture, Sigulda (Latvia). Research Inst. of Biotechnology and Veterinary Medicine Sigra
The aim of the work is to investigate raw milk from different bulls' daughters to clear up the influence of cows' genetic predisposition to milk microbial contamination and somatic cell count (SCC). Particular attention is paid to develop productive cow milk yield, milk fat, milk protein and in recent years, the SCC heredity. The literature describes a variety of lines and families, representatives of the resistance to certain diseases (leucosis, mastitis, tuberculosis, brucellosis, foot disease), it shows the determination of a genetic factor for this trait. If the selection results show increased resistance to a disease, then this indicates a genetic disease resistance and shy. The paper focuses on microbial contamination of raw milk at 7 different studies of bull daughters in the same line for housing, feeding and conditions of use. Raw milk samples were obtained from the breed Latvian brown (LB) from dairy cows shed of cattle shed Saujas, which belongs to SIA Palsa and is located in the civil parish Varini, Smiltene county in the year 2008/2009. Compared between the lines of bulls' daughter milk yield of the sample average value of the uniformity of variance analysis shows that they significantly differ (F=2.452, p=0.039). Comparing each line of bulls' daughters SCC of the sample average value of the uniformity of variance analysis showed that the SCC was statistically significantly different (F=2.083, p=0.075) of the various lines of bulls daughters.
اظهر المزيد [+] اقل [-]Effect of enzymatic hydrolysis on bran microflora
2014
Radenkovs, V., Latvia Univ. of Agriculture, Jelgava (Latvia) | Klava, D., Latvia Univ. of Agriculture, Jelgava (Latvia) | Juhnevica-Radenkova, K., Latvia Univ. of Agriculture, Jelgava (Latvia)
The present study was undertaken to estimate enzymatically hydrolysed and non–hydrolysed wheat (Triticum aestivum) and rye (Secale cereale) bran microflora. Enzymatic hydrolysis was accomplished by α – amylase from Bacillus amyloliquefaciens and by Viscozyme L which contain a wide range of enzymes responsible for the breakdown of carbohydrates into simple sugars. Wheat and rye bran samples were collected from native mills, namely Stock Company (SC) ‘Rigas dzirnavnieks’ wheat bran with large particle size (WLSR), SC ‘Jelgavas dzirnavas’ rye bran with small particle size (RSSJ), SC ‘Dobeles dzirnavnieks’ wheat bran with small particle size (WSSD) and wheat bran with large particle size (WLSD). Gained results indicate that before enzymatic hydrolysis all of the bran samples showed similar microbiological contamination with total plate count (TPC), yeasts and lactic acid bacteria. Enzymatic hydrolysis of bran gives the possibility to partially eliminate the microbiological contamination with TPC, yeasts and lactic acid bacteria. The amount of microorganisms after enzymatic hydrolysis (before storage) were decreased and ranged from 5.26 ± 0.04 to 5.45 ± 0.01 log CFU gE-1, from 4.81 ± 0.01 to 5.60 ± 0.05 log CFU gE-1, and from 4.09 ± 0.01 to 5.10 ± 0.05 log CFU gE-1, respectively. After eight weeks of storage (temperature – 20 ± 1 °C, relative humidity – 40 ± 1%) enumeration of microorganisms showed significant decrease of colony–forming units in all bran samples. The amount of TPC, yeasts and lactic acid bacteria in the control bran samples fluctuated in a range from 4.84 ± 0.04 to 5.49 ± 0.05 log CFU gE-1, from 4.86 ± 0.03 to 5.25 ± 0.03 log CFU g-1, 3.53 ± 0.03 to 4.21 ± 0.02 log CFU gE-1 respectively.
اظهر المزيد [+] اقل [-]Characteristics of dry naturally fermented kvass obtained by spray drying
2016
Lidums, I., Latvia Univ. of Agriculture, Jelgava (Latvia) | Karklina, D., Latvia Univ. of Agriculture, Jelgava (Latvia) | Kirse, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
Kvass is an aromatic soft drink which in a form of powder could be used in dairy or bakery products, or sugar confectionary to expand the diversity of flavours. Spray drying is one of the techniques used for producing powders; however, liquids with high sugar content become sticky during drying process and need additional drying aids to increase glass transition temperature and improve powder stability. The aim of this research was to evaluate the characteristics of dry naturally fermented kvass. Maltodextrin was used in 50, 40 and 25% quantity to kvass dry matter in order to aid the spray drying of naturally fermented non-pasteurised, non-filtered bread kvass. Spray drying of 8 l naturally fermented kvass returned approximately 500 g dry naturally fermented kvass powder with a light brown colour, a pronounced aroma of rye bread and moisture content of 7 ± 0.1%. Microstructure analysis of the spray dried naturally fermented kvass showed irregularly spherical shaped particles, having many shrinkages, breakages and dents on the surface in general. Total viable microorganism count in dry naturally fermented kvass powder was within the recommended levels, traces of lactic acid bacteria were found in all samples. The presence of Bacillus amyloliquefaciens was established in dry naturally fermented kvass powders, with possible contamination from spray dryer.
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