129 resultados para Dry Surfaces.
Resumo:
Using heterogeneous vegetation in alpine grassland through grazing is a necessary component of deintensification of livestock systems and conservation of natural environments. However, better understanding of the dynamics of animal feeding behaviour would improve pasture and livestock grazing managements, particularly in the early part of the spring season when forage is scarce. The changes in behaviour may improve the use of poor pastures. Then, enhancing management practices may conserve pasture and improve animal productivity. Grazing behaviour over 24 In periods by yaks in different physiological states (lactating, dry and replacement heifers) was recorded in the early, dry and later, germinating period of the spring season. Under conditions of inadequate forage, the physiological state of yaks was not the primary factor affecting their grazing and ruminating behaviour. Forage and sward state affected yaks' grazing and ruminating behaviour to a greater extent. Generally, yaks had higher intake and spent more time grazing and ruminating during the later part of the spring season, following germination of forage, than during the earlier dry part of the season. However, the live weight of yaks was less during pasture germination than during the early dry part of the season because the herbage mass is low, and the yaks have to expend much energy to seek feed at this particular time. (c) 2007 Elsevier B.V. All rights reserved.
Resumo:
A feeding trial A as conducted at the farm of Qinghai Academy of Animal and Veterinary Science, Xining, China during 1996 - 1997 with three dry yak cows (initial body weight 163 - 197 kg, age 5 - 6 years) by using 3 x 3 Latin Square Design to determine the effect of levels of feed intake on digestion, nitrogen balance and purine derivative excretion in urine of yak cows. The animals were fed oat hay (nitrogen 13.5 g/kg dry matter (DM), metabolisable energy 8.3 MJ/kg DM), i.e., 0.3, 0.6 and 0.9 of voluntary intake (VI). Each intake treatment lasted for 17 days and the samples (feeds, faeces and urine) were collected during last 7 days of each period. The results indicate that digestibility of dietary DM, OM, NDF and ash declined when intake levels increased from 0.3 to 0.9 VI [DM, from 66.1% to 59.1% (P < 0.05); OM, from 68.1% to 59.9% (P < 0.05); NDF, from 62.1% to 54.3% (P < 0.05); and ash, from 33.9% to 11.8% (P < 0.05)]. Around 0.10 g N/kg W-0.75 was deficient daily in yak cows at 0.3 VI, and positive N balances were observed at 0.6 and 0.9 VI. Intake levels significantly (P < 0.05) affected total PD excretion in yak urine. The proportion of allantoin increased (P < 0.05) and uric acid decreased (P < 0.05) as intake level of feed increased. (C) 2004 Elsevier B.V. All rights reserved.
Resumo:
Tectonic dynamics of metallogenetic fluids is a new crossed subjects among fluid geology, mineral deposit geology and structural geology, and is one of the major current projects of geosciences. It is mainly focused on structures and tectonic dynamic induced by fluid motion, variation of physical condition of fluids (such as temperature and pressure), and interaction between chemical component of fluids and wall rocks in the crust. It takes features of deformation and metamorphysim, which formed during interaction between fluids and rocks and have been perserved in rocks, as basic research objects. After studying types, orders, distributions and fabrics of these features, and analyzing and testing physical and chemical information from these features by some techniques, it is intended to reconstruct moving process of fluids, dynamics of interaction between fluids and rocks, and dynamics of mineralizations. Three problems of tectonic dynamics of metallogenetic fluids, which have not been paid much attentions before, have been studied and discussed in this report. Three relative topics are including: 1)Double-fracturing induced by thermal stress and pressure of fluids and mineralization of Gold-copper in Breccia Pipe at the Qibaoshan in Shandong Province; 2)Parting structures induced by K-metasomatism in the Hougou area, northwestern Heibei province; 3)Migration mechanism of dissolved mass in Fe&S-rich fluids in Hougou gold deposit in Heibei province. After a synthetical study of two years, the author has made some new processes and progresses. The main new advances can be summaried as the following: 1)Thermal stress of fluids formed by temperature difference between fluids and country rock, during upword migration process of fluids with high temperature and pressure, can make rock to break, and some new fractures, which surfaces were uasally dry, formed. The breccia pipe at the Qibaoshan area in Shandong province has some distinct texture of fluidogenous tectonics, the breccia pipe is caused by double-fracturing induced by thermal stress and pressure, distribution of gold-corpper ore bodies are controlled powerfully by fluidogenous tectonics in the breccia pipe. 2)The author discovered a new kind of parting structures in K-alterated rocks in the northwestern part of Hebei province. The parting structures have some distinct geometry and fabrics, it is originated from the acting and reacting fores caused by K-metasomatism. Namely, the crystallizations of metasomatic K-feldspars are a volume expansion process, it would compress the relict fluid bodies, and the pressures in the relict fluid bodies gathered and increased, when the increased pressure of the fluid relict bodies is bigger than the strength of K-feldspars, the K-feldspars were broken with the strong compression, and the parting structures formed. 3)Space position replacing is a important transport pattern of dissolved mass in Fe&S-rich fluid. In addition, basing on views of tectonic dynamics of metallogenic fluids, and time-space texture of fluid-tectonic-lithogenetic-mineralization of the known gold-corpper mineral deposit and the subvolcanic complex at Qibaoshan area in Shandong province, this report does a detail prodict of position-shape-size of two concealed ore-bearing breccia pipe.
