811 research outputs found

    The BGS magnetic field candidate models for the 12th generation IGRF

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    We describe the candidate models submitted by the British Geological Survey for the 12th generation International Geomagnetic Reference Field. These models are extracted from a spherical harmonic ‘parent model’ derived from vector and scalar magnetic field data from satellite and observatory sources. These data cover the period 2009.0 to 2014.7 and include measurements from the recently launched European Space Agency (ESA) Swarm satellite constellation. The parent model’s internal field time dependence for degrees 1 to 13 is represented by order 6 B-splines with knots at yearly intervals. The parent model’s degree 1 external field time dependence is described by periodic functions for the annual and semi-annual signals and by dependence on the 20-min Vector Magnetic Disturbance index. Signals induced by these external fields are also parameterized. Satellite data are weighted by spatial density and by two different noise estimators: (a) by standard deviation along segments of the satellite track and (b) a larger-scale noise estimator defined in terms of a measure of vector activity at the geographically closest magnetic observatories to the sample point. Forecasting of the magnetic field secular variation beyond the span of data is by advection of the main field using core surface flows

    Psychological aspects of the alien contact experience

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    Previous research has shown that people reporting contact with aliens, known as “experiencers”, appear to have a different psychological profile compared to control participants. They show higher levels of dissociativity, absorption, paranormal belief and experience, and possibly fantasy proneness. They also appear to show greater susceptibility to false memories as assessed using the Deese/Roediger-McDermott technique. The present study reports an attempt to replicate these previous findings as well as assessing tendency to hallucinate and self-reported incidence of sleep paralysis in a sample of 19 UK-based experiencers and a control sample matched on age and gender. Experiencers were found to show higher levels of dissociativity, absorption, paranormal belief, paranormal experience, self-reported psychic ability, fantasy proneness, tendency to hallucinate, and self-reported incidence of sleep paralysis. No significant differences were found between the groups in terms of susceptibility to false memories. Implications of the results are discussed and suggestions are made for future avenues of research. Santomauroa, Hamiltona, Rachel Foxa, Thalbourne

    Attributable costs of surgical site infection and endometritis after low transverse cesarean delivery

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    BACKGROUND: Accurate data on costs attributable to hospital-acquired infections are needed in order to determine their economic impact and the cost-benefit of potential preventive strategies. OBJECTIVE: Determine the attributable costs of surgical site infection (SSI) and endometritis (EMM) after cesarean section using two different methods. DESIGN: Retrospective cohort. SETTING: Barnes-Jewish Hospital, a 1250-bed academic tertiary care hospital. PATIENTS: 1,605 women who underwent low transverse cesarean section from 7/1999 – 6/2001. METHODS: Attributable costs of SSI and EMM were determined by generalized least squares (GLS) and propensity score matched-pairs using administrative claims data to define underlying comorbidities and procedures. For the matched-pairs analyses, uninfected control patients were matched to patients with SSI or with EMM based on their propensity to develop infection, and the median difference in costs calculated. RESULTS: The attributable total hospital cost of SSI calculated by GLS was 3,529andbypropensityscorematched−pairswas3,529 and by propensity score matched-pairs was 2,852. The attributable total hospital cost of EMM calculated by GLS was 3,956andbypropensityscorematched−pairswas3,956 and by propensity score matched-pairs was 3,842. The majority of excess costs were associated with room and board and pharmacy costs. CONCLUSIONS: The costs of SSI and EMM were lower than SSI costs reported after more extensive operations. The attributable costs of EMM calculated using the two methods were very similar, while the costs of SSI calculated using propensity score matched-pairs were lower than the costs calculated by GLS. The difference in costs determined by the two methods needs to be considered by investigators performing cost analyses of hospital-acquired infections

    Multi-modal analysis of courtship behaviour in the old world leishmaniasis vector Phlebotomus argentipes

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    BACKGROUND: The sand fly Phlebotomus argentipes is arguably the most important vector of leishmaniasis worldwide. As there is no vaccine against the parasites that cause leishmaniasis, disease prevention focuses on control of the insect vector. Understanding reproductive behaviour will be essential to controlling populations of P. argentipes, and developing new strategies for reducing leishmaniasis transmission. Through statistical analysis of male-female interactions, this study provides a detailed description of P. argentipes courtship, and behaviours critical to mating success are highlighted. The potential for a role of cuticular hydrocarbons in P. argentipes courtship is also investigated, by comparing chemicals extracted from the surface of male and female flies. PRINCIPAL FINDINGS: P. argentipes courtship shared many similarities with that of both Phlebotomus papatasi and the New World leishmaniasis vector Lutzomyia longipalpis. Male wing-flapping while approaching the female during courtship predicted mating success, and touching between males and females was a common and frequent occurrence. Both sexes were able to reject a potential partner. Significant differences were found in the profile of chemicals extracted from the surface of males and females. Results of GC analysis indicate that female extracts contained a number of peaks with relatively short retention times not present in males. Extracts from males had higher peaks for chemicals with relatively long retention times. CONCLUSIONS: The importance of male approach flapping suggests that production of audio signals through wing beating, or dispersal of sex pheromones, are important to mating in this species. Frequent touching as a means of communication, and the differences in the chemical profiles extracted from males and females, may also indicate a role for cuticular hydrocarbons in P. argentipes courtship. Comparing characteristics of successful and unsuccessful mates could aid in identifying the modality of signals involved in P. argentipes courtship, and their potential for use in developing new strategies for vector control

    Selective facial mimicry of native over foreign speakers in preverbal infants.

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    Mimicry, the spontaneous copying of others' behaviors, plays an important role in social affiliation, with adults selectively mimicking in-group members over out-group members. Despite infants' early documented sensitivity to cues to group membership, previous work suggests that it is not until 4 years of age that spontaneous mimicry is modulated by group status. Here we demonstrate that mimicry is sensitive to cues to group membership at a much earlier age if the cues presented are more relevant to infants. 11-month-old infants observed videos of facial actions (e.g., mouth opening, eyebrow raising) performed by models who either spoke the infants' native language or an unfamiliar foreign language while we measured activation of the infants' mouth and eyebrow muscle regions using electromyography to obtain an index of mimicry. We simultaneously used functional near-infrared spectroscopy to investigate the neural mechanisms underlying differential mimicry responses. We found that infants showed greater facial mimicry of the native speaker compared to the foreign speaker and that the left temporal parietal cortex was activated more strongly during the observation of facial actions performed by the native speaker compared to the foreign speaker. Although the exact mechanisms underlying this selective mimicry response will need to be investigated in future research, these findings provide the first demonstration of the modulation of facial mimicry by cues to group status in preverbal infants and suggest that the foundations for the role that mimicry plays in facilitating social bonds seem to be present during the first year of life. [Abstract copyright: Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.

    Dynamic causal modelling on infant fNIRS data: A validation study on a simultaneously recorded fNIRS-fMRI dataset

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    Tracking the connectivity of the developing brain from infancy through childhood is an area of increasing research interest, and fNIRS provides an ideal method for studying the infant brain as it is compact, safe and robust to motion. However, data analysis methods for fNIRS are still underdeveloped compared to those available for fMRI. Dynamic causal modelling (DCM) is an advanced connectivity technique developed for fMRI data, that aims to estimate the coupling between brain regions and how this might be modulated by changes in experimental conditions. DCM has recently been applied to adult fNIRS, but not to infants. The present paper provides a proof-of-principle for the application of this method to infant fNIRS data and a demonstration of the robustness of this method using a simultaneously recorded fMRI-fNIRS single case study, thereby allowing the use of this technique in future infant studies. fMRI and fNIRS were simultaneously recorded from a 6-month-old sleeping infant, who was presented with auditory stimuli in a block design. Both fMRI and fNIRS data were preprocessed using SPM, and analysed using a general linear model approach. The main challenges that adapting DCM for fNIRS infant data posed included: (i) the import of the structural image of the participant for spatial pre-processing, (ii) the spatial registration of the optodes on the structural image of the infant, (iii) calculation of an accurate 3-layer segmentation of the structural image, (iv) creation of a high-density mesh as well as (v) the estimation of the NIRS optical sensitivity functions. To assess our results, we compared the values obtained for variational Free Energy (F), Bayesian Model Selection (BMS) and Bayesian Model Average (BMA) with the same set of possible models applied to both the fMRI and fNIRS datasets. We found high correspondence in F, BMS, and BMA between fMRI and fNIRS data, therefore showing for the first time high reliability of DCM applied to infant fNIRS data. This work opens new avenues for future research on effective connectivity in infancy by contributing a data analysis pipeline and guidance for applying DCM to infant fNIRS data. [Abstract copyright: Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.
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