We studied the diet composition and diet overlap in sympatric red deer (Cervus elaphus hispanicus) and fallow deer (Dama dama) throughout a whole year in order to determine variation due to season, species, sex and age class by analysing rumen contents samples of 81 red and 69 fallow deer shot monthly during 2008–09 in Sierra de Andújar Natural Park, southern Spain. We assessed diet similarity and possible inter- and intra-specific foraging competition. We found different foraging strategies for both species and sexes during constraint periods, and several theoretical considerations of specific interactions and behaviour are discussed with respect to the Mediterranean environment. In both species an annual diet dominated by grasses was recorded, peaking in spring. Browses were an important food resource at the end of winter and at the end of summer, and fruit more in autumn and winter. Red deer ingested a higher proportion of browse than fallow deer, which consumed more acorns and for a longer time showed a better ability to compensate for nutritional constraint periods. An overall decline in diet similarity in summer and at the end of winter led us to assume that exploitative competition between red and fallow deer and even between sexes was probable. Red deer females showed low diet similarity to other deer, while there was a great diet overlap between red deer males and fallow deer females at the end of summer. Differences detected between both two species and sexes do not always support predictions deriving from specific body size and morpho-physiological characteristics, but can probably be explained as a consequence of different metabolic demands. The relationship between plant nutritional attributes and food selection according to reproductive or physiological status and seasonal demands for both sexes and species should be researched in order to perform a better assessment of deer feeding behaviour.

The prevalence of mandibular osteomyelitis, which results in a condition called lumpy jaw, and factors associated with its occurrence were investigated in syntopic free-living populations of red deer (Cervus elaphus hispanicus) and fallow deer (Dama dama) in Spain. The study material consisted of 3,586 mandibles from 2,548 red deer and 1,038 fallow deer shot during sport hunting, herd management culls, and programs for population control between 1988 and 1997 (period 1) and 2002 and 2009 (period 2) in eastern Sierra Morena, southern Spain. Disease prevalence ranged from 0.36% to 10.91% among age groups. Older animals were significantly more likely to be affected than younger ones. Red deer stags had higher prevalence than other groups. There was a significantly higher prevalence in period 1, probably associated with differences in climatic and population conditions. High population densities of female red deer contributed significantly to occurrence of disease. Intensive herd management and poor environmental conditions were considered risk factors that increased susceptibility to disease. The study of this affliction could be useful for monitoring general herd welfare and ecologic changes in Mediterranean ecosystems.

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Two methods of volume measurement were compared, to develop a simple and reliable method for estimating the whole-antler density. We used 10 cast antlers, previously dried and weighed, from 10 different red deer (Cervus elaphus hispanicus) individuals. The volumes were determined by the traditional Archimedes method versus a new parametric volume-modelling technique using a ‘computer-aided design-three dimensions’ (3D-CAD), which is now being used in the biomedical industry in applications such as medical-implant design, tissue engineering and in developing a better understanding of anatomical functionality and morphological analysis. The process paths to follow in the generation of CAD models from cast antlers were described. The whole-antler density was estimated from the weight and volume measurement and a paired-sample comparison procedure was performed to assess differences between volumes as well as densities. Cast-antler weight ranged from 219.93 to 1857.9 g, and the volume estimated by the hydrostatic method was 732.45 ± 474.06 cm3 and by the CAD-3D method it was 730.65 ± 492.59 cm3. The DM density of the antler by the hydrostatic method (Density A) was 1.112 ± 0.120 g/cm3, ranging from 0.915 to 1.345 g/cm3 (Shapiro–Wilks, P = 0.449), and by the 3D-CAD method (Density B) it was 1.112 ± 0.158 g/cm3, ranging from 0.939 to 1.326 g/cm3 (Shapiro–Wilks, P = 0.751). There were no differences in the volume (t = 0.95, P = 0.37) or density (t = 0.54, P = 0.60) between the two methods and the correlation coefficient between Density A and Density B was 0.968. Both methods had similar reliability, although the computing process with the 3D-CAD system calculated antler volume faster than did the traditional hydrostatic weighing. 3D-CAD also avoided cast damage and the methodological problems with larger or smaller antlers or with floatability due to low density, which occur when using the hydrostatic method.

Different kinds of quaternion signal detection problems in continuous-time by using a widely linear processing are dealt with. The suggested solutions are based on an extension of the Karhunen-Loève expansion to the quaternion domain which provides uncorrelated scalar real-valued random coefficients. This expansion presents the notable advantage of transforming the original four-dimensional eigen problem to a one-dimensional problem. Firstly, we address the problem of detecting a quaternion deterministic signal in quaternion Gaussian noise and a version of Pitcher's Theorem is given. Also the particular case of a general quaternion Wiener noise is studied and an extension of the Cameron-Martin formula is presented. Finally, the problem of detecting a quaternion random signal in quaternion white Gaussian noise is tackled. In such a case, it is shown that the detector depends on the quaternion widely linear estimator of the signal.

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