Mammalian adaptation of influenza A(H7N9) virus is limited by a narrow genetic bottleneck

Human infection with avian influenza A(H7N9) virus is associated mainly with the exposure to infected poultry. The factors that allow interspecies transmission but limit human-to-human transmission are unknown. Here we show that A/Anhui/1/2013(H7N9) influenza virus infection of chickens (natural hosts) is asymptomatic and that it generates a high genetic diversity. In contrast, diversity is tightly restricted in infected ferrets, limiting further adaptation to a fully transmissible form. Airborne transmission in ferrets is accompanied by the mutations in PB1, NP and NA genes that reduce viral polymerase and neuraminidase activity. Therefore, while A(H7N9) virus can infect mammals, further adaptation appears to incur a fitness cost. Our results reveal that a tight genetic bottleneck during avian-to-mammalian transmission is a limiting factor in A(H7N9) influenza virus adaptation to mammals. This previously unrecognized biological mechanism limiting species jumps provides a measure of adaptive potential and may serve as a risk assessment tool for pandemic preparedness.published_or_final_versio

Laugh Like You Mean It:Authenticity Modulates Acoustic, Physiological and Perceptual Properties of Laughter

Several authors have recently presented evidence for perceptual and neural distinctions between genuine and acted expressions of emotion. Here, we describe how differences in authenticity affect the acoustic and perceptual properties of laughter. In an acoustic analysis, we contrasted spontaneous, authentic laughter with volitional, fake laughter, finding that spontaneous laughter was higher in pitch, longer in duration, and had different spectral characteristics from volitional laughter that was produced under full voluntary control. In a behavioral experiment, listeners perceived spontaneous and volitional laughter as distinct in arousal, valence, and authenticity. Multiple regression analyses further revealed that acoustic measures could significantly predict these affective and authenticity judgements, with the notable exception of authenticity ratings for spontaneous laughter. The combination of acoustic predictors differed according to the laughter type, where volitional laughter ratings were uniquely predicted by harmonics-to-noise ratio (HNR). To better understand the role of HNR in terms of the physiological effects on vocal tract configuration as a function of authenticity during laughter production, we ran an additional experiment in which phonetically trained listeners rated each laugh for breathiness, nasality, and mouth opening. Volitional laughter was found to be significantly more nasal than spontaneous laughter, and the item-wise physiological ratings also significantly predicted affective judgements obtained in the first experiment. Our findings suggest that as an alternative to traditional acoustic measures, ratings of phonatory and articulatory features can be useful descriptors of the acoustic qualities of nonverbal emotional vocalizations, and of their perceptual implications

A Geospatial Modelling Approach Integrating Archaeobotany and Genetics to Trace the Origin and Dispersal of Domesticated Plants

Background: The study of the prehistoric origins and dispersal routes of domesticated plants is often based on the analysis of either archaeobotanical or genetic data. As more data become available, spatially explicit models of crop dispersal can be used to combine different types of evidence. Methodology/Principal Findings: We present a model in which a crop disperses through a landscape that is represented by a conductance matrix. From this matrix, we derive least-cost distances from the geographical origin of the crop and use these to predict the age of archaeological crop remains and the heterozygosity of crop populations. We use measures of the overlap and divergence of dispersal trajectories to predict genetic similarity between crop populations. The conductance matrix is constructed from environmental variables using a number of parameters. Model parameters are determined with multiple-criteria optimization, simultaneously fitting the archaeobotanical and genetic data. The consilience reached by the model is the extent to which it converges around solutions optimal for both archaeobotanical and genetic data. We apply the modelling approach to the dispersal of maize in the Americas. Conclusions/Significance: The approach makes possible the integrative inference of crop dispersal processes, whil

Effectiveness of Audio-Feedback in Postural Training for Adolescent Idiopathic Scoliosis Patients

The possibility of using learned physiological responses in control of progressive adolescent idiopathic scoliosis (AIS) was investigated. Sixteen (16) AIS patients with progressing or high-risk curves (Cobb's angle between 25° and 35° at start and reducible by lateral bending) were fitted with a device with tone alarm for poor posture. In the first 18 months of application, 3 patients defaulted and 4 showed curve progression > 10° (2 changed to rigid spinal orthoses and 2 underwent surgery). The curves for the other 9 patients were kept under control (within ±5° of Cobb's angle) and 5 of them have reached skeletal maturity and terminated the application. The remaining 4 patients were still using the devices until skeletal maturity or curve progression. The curve control rate was 69%. A long-lasting active spinal control could be achieved through the patient's own spinal muscles. Nevertheless, before the postural training device could become a treatment modality, a long-term study for more AIS patients was necessary. This project is ongoing in the Duchess of Kent Children's Hospital, Sandy Bay, Hong Kong.link_to_subscribed_fulltex

Dental nonmetric investigation of population dynamics at Mayapan

Dental morphological traits have demonstrated utility in the analysis of genetic relationships between populations, within a population, and sometimes even at the familial level. However, despite this potential, such studies of the Maya are rare, though recent years have seen this trend reverse. This chapter contributes to this growing body of research on Maya dental morphology by demonstrating the utility of this approach to illuminate aspects of Mayapan’s internal population dynamics