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The semi-arid Hindu-Kush-Karakoram-Himalayan region of Pakistan covers 72,000 sq km with a rainfall of 100-400 mm per year5. Limited arable land and water scarcity have made subsistence farming the dominant agro-pastoral farming system. Each household keeps a range of ruminant livestock species such as goats, cattle, sheep, donkeys and yaks their proportion in the herd are 0.53, 0.23, 0.19, 0.03 and 0.02 respectively. In winter, livestock are confined and stall-fed on stored roughages or grazed on marginal lands and fallow agricultural fields close to the villages. The aim of this study was to quantify nutritional inputs in terms of metabolisable energy resources, and to compare these with ME requirements of the animals for maintenance over winter.
The effect of free-surface drift layers on the maximum height that
a steady wave can
attain without breaking is explored through experiments and numerical simulations.
In the experiments, the waves are generated by towing a two-dimensional
submerged hydrofoil at constant depth, speed and angle of attack. The drift
generated by towing a plastic sheet on the water surface ahead of the hydrofoil.
is found that the presence of this drift layer (free-surface wake) dramatically
the maximum non-breaking wave height and that this wave height correlates
with the surface drift velocity. In the simulations, the inviscid two-dimensional
nonlinear Euler equations are solved numerically. Initially symmetric wave
superimposed on a parallel drift layer whose mean flow characteristics
in the experiments. It is found that for large enough initial wave amplitudes
forms at the crest on the forward face of the wave and the vorticity fluctuations
under the surface in this region grow dramatically in time. This behaviour
is taken as
a criterion to indicate impending wave breaking. The maximum non-breaking
elevations obtained in this way are in good agreement with the experimental
This paper is a review of the course of research during the past decade into the history of indigenous metal working in sub-Saharan Africa. It comprises three sections: a summary of the chronology of early metallurgy and the spread of metal working; a description of African metal working in terms of mining, smelting and smithing, with particular emphasis on recent interpretations of the iron-smelting technology; and a conclusion summarizing the main developments and some lines of future enquiry. A glossary of technical terms used in this paper is appended.
The successful re-breeding of suckler and dairy cows is vital to the economics of farming cattle. The gestation length of cows is 280-290 days, so the optimum interval after calving for the subsequent mating is 75-85 days if a 365 day calving interval is to be achieved. Average calving rates to a given service are of the order of 0.5 to 0.6 (Diskin and Sreenan, 1980). Most practical management strategies allow cows to be mated during a 7-10 week period (giving 3 or 4 opportunities to show oestrus). The chance of conception improves with each oestrus cycle following calving, so the earlier a cow begins to show oestrus activity after calving the more likely she is to be successfully mated, because the early, less fertile oestrus cycles, are likely to happen before the planned mating period.
In the general election of October 1974 the Scottish National Party gained 30·4 per cent of the vote in Scotland. This result and the build-up to it in the previous two elections, seemed to indicate a new pattern for Scottish voting. British and American writers had drawn attention to the decline of partisanship as a basis for voting. In Britain, the class basis of this partisanship had been dominant but now appeared to recede. Growing support for the SNP might have been an extension of this. Some went further and argued that a new issue – self-government for Scotland – had displaced class loyalties.
Recent excavations in Belize have resulted in the discovery of an earlier period of sedentary occupation than has hitherto been documented in the Maya Lowlands. The Swasey phase is stratigraphically antecedent to occupations of the early Middle Formative, the earliest horizon located until now, and associated radiocarbon dates suggest a persistence from 2000–1000 b.c./2500–1300 B.C. The ceramic and lithic material culture of the phase are described, together with architectural construction and burial practice, and the overall cultural identity is recognized as ancestral to the known Maya Lowland Formative. External contacts of the Cuello site are documented by exotic minerals, and the possible external antecedents for the Swasey ceramic tradition are canvassed.
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