Vermindering ammoniakemissie uit een ligboxenstal door spoelen van een hellende betonvloer = Reduction of a ammonia emission from a cubicle house by flushing an inclined concrete floor

In de stalperiode 1990-1991 is in een mechanisch geventileerde rundveestal, waarin 34 melkkoeien waren gehuisvest, onderzoek uitgevoerd naar de invloed op de ammoniakemissie van spoelen over een hellende betonvloer met giergoot. Met een spoelinstallatie, waarvan de spoelleidingen zich aan weerszijden van de loopgangen bevonden, werd de vloer eenmaal per twee uur gespoeld, nadat de mest met een schuif was verwijderd. De ammoniakemissie, een aantal klimaatsvariabelen en het waterverbruik werden gemeten bij twee verschillende spoelvarianten. Deze werden gekenmerkt door vier variabelen, die op verschillende niveaus konden worden ingesteld, te weten: de waterdruk, de spoeltijd, de frequentie waarmee gespoeld werd en de nippeldiameter. De hoogste emissiereductie bedroeg 34% t.o.v. een situatie zonder spoelen bij een spoeldruk van 60 kPa, een spoeltijd van 2 seconden en een nippeldiameter van 5 mm. Per dag werd 50 l water per koe verbruikt. Er werd geen indicatie gevonden dat de schuiffrequentie van invloed is op de emissie. Bij de andere instelling werd gespoeld met een druk van 150 kPa, een spoeltijd van 4 seconden en een nippeldoorsnede van 3 mm. Het spoelwaterverbruik bij deze instelling was 28 l/koe.dag. De emissiereductie bedroeg 14% t.o.v. de situatie zonder spoelen

Ammoniakemissiereductie door spoelen van een hellende, gecoate betonvloer in een rundveestal = Reduction of ammonia emission by flushing an inclined coated concrete floor in a cattle house

In stalperiode 1991-1992 is in een rundveestal, waarin 34 melkkoeien waren gehuisvest, onderzoek uitgevoerd naar de invloed op de ammoniakemissie van spoelen met water over een hellende, gecoate betonvloer. Met een spoelinstallatie waarvan de spoelleidingen zich aan weerszijden van de loopgangen bevonden, werd de vloer eenmaal per twee uur gespoeld. De ammoniakemissie, een aantal klimaatsvariabelen en het waterverbruik werden gemeten bij twee verschillende spoelvarianten. Deze werden gekenmerkt door vier variabelen: de waterdruk, de spoeltijd, de frequentie waarmee gespoeld werd en de nippeldiameter, die op verschillende niveaus konden worden ingesteld. De hoogste emissiereductie bedroeg 33% ten opzichte van een situatie zonder spoelen. Deze reductie werd bereikt bij een spoeldruk van 200 kPa, een spoeltijd van 4 seconden en een nippeldiameter van 3 mm. Per dag werd 24 l water per koe verbruikt. Bij de andere instelling werd gespoeld met een druk van 250 kPa, een spoeltijd van 2,5 seconden en een nippeldoorsnede van 3 mm. De emissiereductie bedroeg 26% bij een dagelijks spoelwaterverbruik van 20 l/koe

A comparison of facial expression properties in five hylobatid species

Little is known about facial communication of lesser apes (family Hylobatidae) and how their facial expressions (and use of) relate to social organization. We investigated facial expressions (defined as combinations of facial movements) in social interactions of mated pairs in five different hylobatid species belonging to three different genera using a recently developed objective coding system, the Facial Action Coding System for hylobatid species (GibbonFACS). We described three important properties of their facial expressions and compared them between genera. First, we compared the rate of facial expressions, which was defined as the number of facial expressions per units of time. Second, we compared their repertoire size, defined as the number of different types of facial expressions used, independent of their frequency. Third, we compared the diversity of expression, defined as the repertoire weighted by the rate of use for each type of facial expression. We observed a higher rate and diversity of facial expression, but no larger repertoire, in Symphalangus (siamangs) compared to Hylobates and Nomascus species. In line with previous research, these results suggest siamangs differ from other hylobatids in certain aspects of their social behavior. To investigate whether differences in facial expressions are linked to hylobatid socio-ecology, we used a Phylogenetic General Least Square (PGLS) regression analysis to correlate those properties with two social factors: group-size and level of monogamy. No relationship between the properties of facial expressions and these socio-ecological factors was found. One explanation could be that facial expressions in hylobatid species are subject to phylogenetic inertia and do not differ sufficiently between species to reveal correlations with factors such as group size and monogamy level. Am. J. Primatol. 76:618-628, 2014

Hemodynamic and biochemical effects of the AT1 receptor antagonist irbesartan in hypertension

We studied the hemodynamic, neurohumoral, and biochemical effects of the novel angiotensin type 1 (AT1) receptor antagonist irbesartan in 86 untreated patients with essential hypertension on a normal sodium diet. According to a double-blind parallel group trial, patients were randomized to a once-daily oral dose of the AT1 receptor antagonist (1, 25, or 100 mg) or placebo after a placebo run-in period of 3 weeks. Randomization medication was given for 1 week. Compared with placebo, 24-hour ambulatory blood pressure did not change with the 1-mg dose, and it fell (mean and 95% confidence interval) by 7.0 (4.2-9.8)/6.1 (3.9-8.1) mm Hg with the 25-mg dose and by 12.1 (8.1-16.2)/7.2 (4.9-9.4) mm Hg with the 100-mg dose. Heart rate did not change during either dose. With the 25-mg dose, the antihypertensive effect was attenuated during the second half of the recording, and wi

Mesozoic retroposons reveal parrots as the closest living relatives of passerine birds

The relationships of passerines (such as the well-studied zebra finch) with non-passerine birds is one of the great enigmas of avian phylogenetic research, because decades of extensive morphological and molecular studies yielded highly inconsistent results between and within data sets. Here we show the first application of the virtually homoplasy-free retroposon insertions to this controversy. Our study examined ~200,000 retroposon-containing loci from various avian genomes and retrieved 51 markers resolving early bird phylogeny. Among these, we obtained statistically significant evidence that parrots are the closest and falcons the second-closest relatives of passerines, together constituting the Psittacopasserae and the Eufalconimorphae, respectively. Our new and robust phylogenetic framework has substantial implications for the interpretation of various conclusions drawn from passerines as model organisms. This includes insights of relevance to human neuroscience, as vocal learning (that is, birdsong) probably evolved in the psittacopasseran ancestor, >30 million years earlier than previously assumed

The evolutionary roots of creativity: mechanisms and motivations

Funding: MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland). MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions.We consider the evolution of cognition and the emergence of creative behaviour, in relation to vocal communication. We address two key questions: (i) what cognitive and/or social mechanisms have evolved that afford aspects of creativity?; (ii) has natural and/or sexual selection favoured human behaviours considered ‘creative’? This entails analysis of ‘creativity’, an imprecise construct: comparable properties in non-humans differ in magnitude and teleology from generally agreed human creativity. We then address two apparent problems: (i) the difference between merely novel productions and ‘creative’ ones; (ii) the emergence of creative behaviour in spite of high cost: does it fit the idea that females choose a male who succeeds in spite of a handicap (costly ornament); or that creative males capable of producing a large and complex song repertoire grew up under favourable conditions; or a demonstration of generally beneficial heightened reasoning capacity; or an opportunity to continually reinforce social bonding through changing communication tropes; or something else? We illustrate and support our argument by reference to whale and bird song; these independently evolved biological signal mechanisms objectively share surface properties with human behaviours generally called ‘creative’. Studying them may elucidate mechanisms underlying human creativity; we outline a research programme to do so.PostprintPeer reviewe

Comprehensive DNA barcode coverage of North American birds

DNA barcoding seeks to assemble a standardized reference library for DNA-based identification of eukaryotic species. The utility and limitations of this approach need to be tested on well-characterized taxonomic assemblages. Here we provide a comprehensive DNA barcode analysis for North American birds including 643 species representing 93% of the breeding and pelagic avifauna of the USA and Canada. Most (94%) species possess distinct barcode clusters, with average neighbour-joining bootstrap support of 98%. In the remaining 6%, barcode clusters correspond to small sets of closely related species, most of which hybridize regularly. Fifteen (2%) currently recognized species are comprised of two distinct barcode clusters, many of which may represent cryptic species. Intraspecific variation is weakly related to census population size and species age. This study confirms that DNA barcoding can be effectively applied across the geographical and taxonomic expanse of North American birds. The consistent finding of constrained intraspecific mitochondrial variation in this large assemblage of species supports the emerging view that selective sweeps limit mitochondrial diversity

Habitat-related birdsong divergence: a multi-level study on the influence of territory density and ambient noise in European blackbirds

Song plays an important role in avian communication and acoustic variation is important at both the individual and population level. Habitat-related variation between populations in particular can reflect adaptations to the environment accumulated over generations, but this may not always be the case. In this study, we test whether variation between individuals matches local conditions with respect to noise level and territory density to examine whether short-term flexibility could contribute to song divergence at the population level. We conducted a case study on an urban and forest population of the European blackbird and show divergence at the population level (i.e. across habitats) in blackbird song, anthropogenic noise level and territory density. Unlike in several other species, we found a lack of any correlation at the individual level (i.e. across individuals) between song features and ambient noise. This suggests species-specific causal explanations for noise-dependent song differentiation which are likely associated with variation in song-copying behaviour or feedback constraints related to variable singing styles. On the other hand, we found that at the level of individual territories, temporal features, but not spectral ones, are correlated to territory density and seasonality. This suggests that short-term individual variation can indeed contribute to habitat-dependent divergence at the population level. As this may undermine the potential role for song as a population marker, we conclude that more investigations on individual song flexibility are required for a better understanding of the impact of population-level song divergence on hybridisation and speciation

Call playback artificially generates a temporary cultural style of high affiliation in marmosets

Cultural variation can be conceptualised in two main ways: as culture-specific qualitative differences in behavioural form, and also as quantitative variation in performance of constellations of universal behaviours (cultural style). Despite observation of both types in wild non-human primates, diffusion of qualitative culture has been scrutinised extensively experimentally whilst within-species transmission of cultural style has remained entirely unexplored. Here we investigated whether a cultural style of high affiliation could be artificially generated in a nonhuman primate (Callithrix jacchus), by daily playback of conspecific affiliative calls simulating nearby amicable individuals. We found that vocalisation playback influenced monkeys to spend more time in affiliative behaviours outwith playback hours, relative to silent playback. The effect was specific to affiliation, with no impact on other categories of affect. This change did not persist into the final phase of observation after all playbacks were complete. Findings are consistent with a temporary shift in cultural style effected through vocalisation playback, supporting existence of this conception of culture in wild primates and indicating auditory social contagion as a potential diffusion mechanism. The method presented here will allow researchers to test hypotheses concerning cultural transmission of cultural style, and the underlying processes, across a range of contexts and species

Singing in the Rain Forest: How a Tropical Bird Song Transfers Information

How information transmission processes between individuals are shaped by natural selection is a key question for the understanding of the evolution of acoustic communication systems. Environmental acoustics predict that signal structure will differ depending on general features of the habitat. Social features, like individual spacing and mating behavior, may also be important for the design of communication. Here we present the first experimental study investigating how a tropical rainforest bird, the white-browed warbler Basileuterus leucoblepharus, extracts various information from a received song: species-specific identity, individual identity and location of the sender. Species-specific information is encoded in a resistant acoustic feature and is thus a public signal helping males to reach a wide audience. Conversely, individual identity is supported by song features susceptible to propagation: this private signal is reserved for neighbors. Finally, the receivers can locate the singers by using propagation-induced song modifications. Thus, this communication system is well matched to the acoustic constraints of the rain forest and to the ecological requirements of the species. Our results emphasize that, in a constraining acoustic environment, the efficiency of a sound communication system results from a coding/decoding process particularly well tuned to the acoustic properties of this environment