Water quality at the habitat of the Podostemaceae in Ghana

The water quality and river catchment characteristics of Ankasa, Asuboni and Pawnpawn rivers in Ghana where Podostemaceae grow were determined using standard methods. The altitude of the sites ranged from 100 to 290 mabove sea level. The catchment areas for the sites vary from 35 to 171 km2. Between 10–81% of the catchment areas of the sites are within forest reserves. The study showed that the Podostemaceae in Ghana inhabit rivers with the following range of physico-chemical characteristics: pH 6.7–7.3, calcium 2.2–16.0 mg l-1, ammonia-nitrogen 0.07–0. 90 mg l-1, chloride 6.8–38.0 mg l-1, electrical conductivity 26.4–138.0 mS cm-1, magnesium 0.4–9.7 mg l-1, nitrate-nitrogen 0.1–0.6 mg l-1, phosphate 0.01–0.30 mgl-1, silicate 0-21.4 mg l-1 and sulphate 1.5–20.8 mg l-1. The results indicate the quality of water at the habitat of Podostemaceae in Ghana

Effects of Naked-Neck and Frizzle Genes on Growth Performance and Carcass Characteristics Of Crossbred Cockerels

An experiment was carried out to evaluate the performance of crossbred naked-neck and frizzle cockerel genotypes namely: (i) Na/naF/f, (ii) Na/naf/f (iii) na/naF/f and (iv) na/naf/f. These crossbred second generation cockerels were generated from a reciprocal crossing between crossbred heterozygous naked-neck (50% indigenous naked-neck and 50% Lohman Brown) and frizzle (50% indigenous frizzle and 50% Lohman Brown) stocks. One hundred and twenty (120), eight-week old crossbred cockerels (thirty each of the four genotypic groups) were randomly assigned to nine deep litter pens in a Completely Randomized Design for six weeks and their growth and carcass characteristics evaluated. The birds were provided with grower mash ad lib throughout the experimental period. At the end of the trial, 3 cockerels from each of the four genotypic groups were randomly selected and slaughtered and their carcass parameters determined. The results indicated that there was no significant genotype effect on both initial and final body weights. There were also no genotype effects on weight gain, feed intake, mortality and feed conversion ratio. With respect to carcass yield characteristics, the double heterozygous cockerels had significantly (P<0.05) higher values in terms of percent leg yield, breast yield, thigh yield, dressed weight and dressing percentage

Water chemistry and the distribution of Podostemaceae in Ghana

The physico-chemical parameters of several rivers in southern Ghana were determined during the dry season.  Other environmental features, e.g. canopy cover, rock substrate type, etc. of each site sampled were also recorded.  Four Podostemaceae species were recorded in 10 of the rivers sampled.  The distribution of the Podostemaceae appeared to relate to availability of rock substrate, open canopy and some level of plant nutrients, e.g. phosphates and nitrates in the water.  Further data must be collected at the sites where Podostemaceae grow in the tropics, particularly in Africa, to enable a better understanding of the contribution of river chemistry and other environmental parameters to the distribution of the Podostemaceae.

Sensing sociality in dogs: what may make an interactive robot social?

This study investigated whether dogs would engage in social interactions with an unfamiliar robot, utilize the communicative signals it provides and to examine whether the level of sociality shown by the robot affects the dogs' performance. We hypothesized that dogs would react to the communicative signals of a robot more successfully if the robot showed interactive social behaviour in general (towards both humans and dogs) than if it behaved in a machinelike, asocial way. The experiment consisted of an interactive phase followed by a pointing session, both with a human and a robotic experimenter. In the interaction phase, dogs witnessed a 6-min interaction episode between the owner and a human experimenter and another 6-min interaction episode between the owner and the robot. Each interaction episode was followed by the pointing phase in which the human/robot experimenter indicated the location of hidden food by using pointing gestures (two-way choice test). The results showed that in the interaction phase, the dogs' behaviour towards the robot was affected by the differential exposure. Dogs spent more time staying near the robot experimenter as compared to the human experimenter, with this difference being even more pronounced when the robot behaved socially. Similarly, dogs spent more time gazing at the head of the robot experimenter when the situation was social. Dogs achieved a significantly lower level of performance (finding the hidden food) with the pointing robot than with the pointing human; however, separate analysis of the robot sessions suggested that gestures of the socially behaving robot were easier for the dogs to comprehend than gestures of the asocially behaving robot. Thus, the level of sociality shown by the robot was not enough to elicit the same set of social behaviours from the dogs as was possible with humans, although sociality had a positive effect on dog-robot interactions. © 2013 Springer-Verlag Berlin Heidelberg