Factors affecting diet, habitat selection and breeding success of the African Crowned Eagle Stephanoaetus coronatus in a fragmented landscape

This study aimed to identify variables that affect habitat selection and nesting success of the African Crowned Eagle Stephanoaetus coronatus, the largest forest raptor, in north-eastern South Africa. A preference for nesting in the Northern Mistbelt Forest vegetation type was established and 82% of all nests were located in indigenous trees. Nest abandonment was less common when distances to the nearest neighbour were greater. The diet of this species was investigated by examination of prey remains beneath nests and verified by comparison with museum specimens. In total, 156 remains were found, representing a minimum of 75 prey individuals. The diet of African Crowned Eagles constituted almost entirely mammals (99%), which were predominantly antelopes (61%) and monkeys (25%). It was also found that the proportion of primates in the diet correlates with latitude: populations in equatorial latitudes have a higher proportion of primates in their diets, whereas further south antelopes are a much more common diet component

Changes in the variability and periodicity of precipitation in Scotland

This paper analyses the temporal and spatial changes in the amount and variability of rainfall in Scotland. The sequential Mann–Kendall test reveals that total annual precipitation has increased across Scotland since the 1970s with increasing trends in variability beginning between the mid-1960s and the mid-1970s. Whilst temporally consistent increasing trends in precipitation totals prevail in the West, many weather stations in the East have experienced subsequent trend turning points in the following two decades, explaining the larger magnitude of the trends in western Scotland in recent decades. Trend analyses on six measures of rainfall variability indicate an increase in rainfall variability during the period 1961–2000, as measured by the intra-annual variance, the winter to summer precipitation ratio and the annual cumulative sum range, with decreasing trends observed in the number of dry days. Periodicities associated with the North Atlantic Oscillation and the Atlantic Multidecadal Oscillation could explain the observed temporal variability of rainfall

The circular dichroism of a,b-unsaturated ketones. I. Circular dichroism in the singlet-singlet and singlet-triplet n «p* transitions of steroidal 4-en-3-ones

The circular dichroism from 22 steroidal 4-en-3-ones in cyclohexane solution has been recorded through the wavelength range 400-265 nm. It is shown that both the singlet-triplet and the singlet-singlet n → π* electronic transitions contribute. Through examination of evidence from c.d. and X-ray structure analysis, it is concluded that the conformation of the chromophore and its immediate environment remains constant under the conditions of measurement. In three of the 6β- substituted compounds the normal, highly structured, negative Cotton effect from the singlet-singlet n → π* transition is modified by positive c.d. with the same vibrational structuring. The origin of the positive contribution is discussed.</jats:p