Fast acoustic streaming in standing waves : Generation of an additional outer streaming cell

Rayleigh streaming in a cylindrical acoustic standing waveguide is studied both experimentally and numerically for nonlinear Reynolds numbers from 1 to 30. Streaming velocity is measured by means of laser Doppler velocimetry in a cylindrical resonator filled with air at atmospheric pressure at high intensity sound levels. The compressible Navier-Stokes equations are solved numerically with high resolution finite difference schemes. The resonator is excited by shaking it along the axis at imposed frequency. Results of measurements and of numerical calculation are compared with results given in the literature and with each other. As expected, the axial streaming velocity measured and calculated agrees reasonably well with the slow streaming theory for small ReNL but deviates significantly from such predictions for fast streaming (ReNL > 1). Both experimental and numerical results show that when ReNL is increased, the center of the outer streaming cells are pushed toward the acoustic velocity nodes until counter-rotating additional vortices are generated near the acoustic velocity antinodes

Reliable microsatellite genotyping of the Eurasian badger (Meles meles) using faecal DNA

The potential link between badgers and bovine tuberculosis has made it vital to develop accurate techniques to census badgers. Here we investigate the potential of using genetic profiles obtained from faecal DNA as a basis for population size estimation. After trialling several methods we obtained a high amplification success rate (89%) by storing faeces in 70% ethanol and using the guanidine thiocyanate/silica method for extraction. Using 70% ethanol as a storage agent had the advantage of it being an antiseptic. In order to obtain reliable genotypes with fewer amplification reactions than the standard multiple-tubes approach, we devised a comparative approach in which genetic profiles were compared and replication directed at similar, but not identical, genotypes. This modified method achieved a reduction in polymerase chain reactions comparable with the maximumlikelihood model when just using reliability criteria, and was slightly better when using reliability criteria with the additional proviso that alleles must be observed twice to be considered reliable. Our comparative approach would be best suited for studies that include multiple faeces from each individual. We utilized our approach in a well-studied population of badgers from which individuals had been sampled and reliable genotypes obtained. In a study of 53 faeces sampled from three social groups over 10 days, we found that direct enumeration could not be used to estimate population size, but that the application of mark–recapture models has the potential to provide more accurate results

Mendelian Inheritance Pattern and High Mutation Rates of Microsatellite Alleles in the Diatom Pseudo-nitzchia multistriata

The diatom Pseudo-nitzschia multistriata exhibits a diplontic life cycle composed of an extensive phase of vegetative cell division and a brief phase of sexual reproduction. To explore genotypic stability, we genotyped seven polymorphic microsatellite loci in 26 monoclonal strains over 3–16 months in a culture maintenance regime. Moreover, to assess inheritance patterns of the microsatellite alleles, we genotyped 246 F1 strains resulting from four mating experiments between parental strains of know genotype. Results generally conformed expectations according to Mendelian inheritance patterns, but deviations were detected indicating mutations during sexual reproduction. A total of forty-two mutations were detected in the clonal cultures over time. Microsatellites with more core-repeats accumulated mutations faster. The mutation rate varied significantly across loci and strains. A binomial mass function and a computer simulation showed that the mutation rate was significantly higher during the first months of culture (μ≈3×10-3 per locus per cell division) and decreased to μ≈1×10-3 in the strains kept for 16 months. Our results suggest that genetic mutations acquired in both the vegetative phase and sexual reproduction add to the allelic diversity of microsatellites, and hence to the genotypic variation present in a natural population

Direct and indirect causal effects of heterozygosity on fitness-related traits in Alpine ibex

Heterozygosity–fitness correlations (HFCs) are a useful tool to investigate the effects of inbreeding in wild populations, but are not informative in distinguishing between direct and indirect effects of heterozygosity on fitness-related traits. We tested HFCs in male Alpine ibex (Capra ibex) in a free-ranging population (which suffered a severe bottleneck at the end of the eighteenth century) and used confirmatory path analysis to disentangle the causal relationships between heterozygosity and fitness-related traits. We tested HFCs in 149 male individuals born between 1985 and 2009. We found that standardized multi-locus heterozygosity (MLH), calculated from 37 microsatellite loci, was related to body mass and horn growth, which are known to be important fitness-related traits, and to faecal egg counts (FECs) of nematode eggs, a proxy of parasite resistance. Then, using confirmatory path analysis, we were able to show that the effect of MLH on horn growth was not direct but mediated by body mass and FEC. HFCs do not necessarily imply direct genetic effects on fitness-related traits, which instead can be mediated by other traits in complex and unexpected ways

Au seuil de l’écrit, au seuil de l’oral

En m’appuyant sur mon expérience personnelle du livre et de l’écrit, mais aussi sur ma posture d’ethnographe pendant plusieurs décennies dans le Centre-Ouest de la France, je me suis attaché à évoquer quelques attitudes assez bien partagées, engendrées par les livres, du moins par certains d’entre eux, désignés à la vindicte. Puis, je me suis arrêté sur des exemples d’ethnotextes où s’entrelacent écrit et oral, enfin j’ai voulu rappeler certains tabous linguistiques élémentaires, parfois très anciens, du domaine de la culture de l’oralité. Le rapprochement d’anecdotes et de signes qui relèvent de l’intime, dispersés dans le quotidien rural, dénote une « mémoire longue » et bien enracinée qui transfère des savoirs anciens jusqu’à nous.Based on my personal experience of books and writing and on my position as ethnographer in west central France, I have tried to evoke some of the shared attitudes generated by those books designated as condemnable. I then focused on samples of ethnotexts that mingle the oral and written. Then, I decided to recall certain basic linguistic taboos, some quite ancient, belonging to the area of oral culture. By bringing together anecdotes and signs stemming from the intimate sphere and dispersed in the rural everyday, one denotes a “long memory” that is well rooted and that transfers ancient knowledge to our very day

Mitigating Scoring Errors in Microsatellite Data from Wild Populations

Microsatellite data are widely used to test ecological and evolutionary hypotheses in wild populations. In this paper, we consider three typical sources of scoring errors capable of biasing biological conclusions: stuttering, large-allele dropout and null alleles. We describe methods to detect errors and propose conventions to mitigate scoring errors and report error rates in studies of wild populations. Finally, we discuss potential bias in ecological or evolutionary conclusions based on data sets containing these scoring errors

Italian wolves (Canis lupus italicus Altobello, 1921) and molecular detection of taeniids in the Foreste Casentinesi National Park, Northern Italian Apennines

After centuries of massive decline, the recovery of the wolf (Canis lupus italicus) in Italy is a typical conservation success story. To learn more about the possible role of parasites in the wolves' individual and population health and conservation we used non-invasive molecular approaches on fecal samples to identify individual wolves, pack membership, and the taeniids present, some of which are zoonotic. A total of 130 specimens belonging to 54 wolves from eight packs were collected and examined. Taeniid eggs were isolated using a sieving/flotation technique, and the species level was identified by PCR (gene target: 12S rRNA and nad1). Taeniid prevalence was 40.7% for Taenia hydatigena, 22.2% for T. krabbei, 1.8% for T. polyachanta and 5.5% for Echinococcus granulosus. The prevalence of E. granulosus is discussed. Our results show that the taeniid fauna found in wolves from the Foreste Casentinesi National Park is comparable to that described for other domestic and wild Italian canids and provides insights into the wolves' diet and their relationship with the environment

The ART of mating : alternative reproductive tactics and mating success in a nest-guarding fish

Fish use different modalities to access mates for reproduction, often referred to as Alternative Reproductive Tactics (ARTs). ARTs are an example of coexisting phenotypes, which have to hold some degree of reproductive success to persist in a population. In the Mediterranean damselfish (Chromis chromis), territorial males colonise nests on rocky reefs, competing for females, while sneaker males attempt to parasitically spawn in those nests. Here we combine behavioural observations in the field with molecular analyses, using bi-parentally and maternally inherited markers, to investigate reproductive success patterns of the two observed male ARTs in terms of number of eggs sired and number of females contributing to each nest. Cuckoldry was observed in every nest sampled, with at least two and up to seven sneakers per nest; however, the nesting male always significantly fathered the large majority of the eggs (on average 49%) in each clutch. Each sneaker fathered around 7% of the clutch. The average number of females whose eggs were fertilised by nesting males was 6.76 (ranging 2-13), while each sneaker on average fertilised the eggs of 1.74 (range 1-8) females. Using this sibship reconstruction, we investigated some of the factors involved in the regulation of the dynamic equilibrium of reproductive success between the two ARTs showed by C. chromis males. Our results show that the sneakers’ reproductive success was positively linked to egg clutch size; the density of individuals in the nesting area negatively affected the size of egg clutches; the rate of defence behaviours performed by nesting males negatively influenced the number of females contributing to each nest