147 research outputs found
Eye movements explain decodability during perception and cued attention in MEG
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202750.pdf (publisher's version ) (Open Access)Eye movements are an integral part of human perception, but can induce artifacts in many magneto-encephalography (MEG) and electroencephalography (EEG) studies. For this reason, investigators try to minimize eye movements and remove these artifacts from their data using different techniques. When these artifacts are not purely random, but consistent regarding certain stimuli or conditions, the possibility arises that eye movements are actually inducing effects in the MEG signal. It remains unclear how much of an influence eye movements can have on observed effects in MEG, since most MEG studies lack a control analysis to verify whether an effect found in the MEG signal is induced by eye movements. Here, we find that we can decode stimulus location from eye movements in two different stages of a working memory match-to-sample task that encompass different areas of research typically done with MEG. This means that the observed MEG effect might be (partly) due to eye movements instead of any true neural correlate. We suggest how to check for eye movement effects in the data and make suggestions on how to minimize eye movement artifacts from occurring in the first place.10 p
Electron screening in molecular fusion reactions
Recent laboratory experiments have measured fusion cross sections at
center-of-mass energies low enough for the effects of atomic and molecular
electrons to be important. To extract the cross section for bare nuclei from
these data (as required for astrophysical applications), it is necessary to
understand these screening effects. We study electron screening effects in the
low-energy collisions of Z=1 nuclei with hydrogen molecules. Our model is based
on a dynamical evolution of the electron wavefunctions within the TDHF scheme,
while the motion of the nuclei is treated classically. We find that at the
currently accessible energies the screening effects depend strongly on the
molecular orientation. The screening is found to be larger for molecular
targets than for atomic targets, due to the reflection symmetry in the latter.
The results agree fairly well with data measured for deuteron collisions on
molecular deuterium and tritium targets.Comment: 15 Page RevTeX document, twelve postscript figures, now in a uufile
packag
Skin-associated lactic acid bacteria from North American bullfrogs as potential control agents of batrachochytrium dendrobatidis
The fungal pathogen Batrachochytrium dendrobatidis (Bd) is the causative agent of chytridiomycosis and has been a key driver in the catastrophic decline of amphibians globally. While many strategies have been proposed to mitigate Bd outbreaks, few have been successful. In recent years, the use of probiotic formulations that protect an amphibian host by killing or inhibiting Bd have shown promise as an effective chytridiomycosis control strategy. The North American bullfrog (Lithobates catesbeianus) is a common carrier of Bd and harbours a diverse skin microbiota that includes lactic acid bacteria (LAB), a microbial group containing species classified as safe and conferring host benefits. We investigated beneficial/probiotic properties: anti-Bd activity, and adhesion and colonisation characteristics (hydrophobicity, biofilm formation and exopolysaccharide-EPS production) in two confirmed LAB (cLAB-Enterococcus gallinarum CRL 1826, Lactococcus garvieae CRL 1828) and 60 presumptive LAB (pLAB) [together named as LABs] isolated from bullfrog skin.We challenged LABs against eight genetically diverse Bd isolates and found that 32% of the LABs inhibited at least one Bd isolate with varying rates of inhibition. Thus, we established a score of sensitivity from highest (BdGPL AVS7) to lowest (BdGPL C2A) for the studied Bd isolates. We further reveal key factors underlying host adhesion and colonisation of LABs. Specifically, 90.3% of LABs exhibited hydrophilic properties that may promote adhesion to the cutaneous mucus, with the remaining isolates (9.7%) being hydrophobic in nature with a surface polarity compatible with colonisation of acidic, basic or both substrate types. We also found that 59.7% of LABs showed EPS synthesis and 66.1% produced biofilm at different levels: 21% weak, 29% moderate, and 16.1% strong. Together all these properties enhance colonisation of the host surface (mucus or epithelial cells) and may confer protective benefits against Bd through competitive exclusion. Correspondence analysis indicated that biofilm synthesis was LABs specific with high aggregating bacteria correlating with strong biofilm producers, and EPS producers being correlated to negative biofilm producing LABs. We performed Random Amplified Polymorphic DNA (RAPD)-PCR analysis and demonstrated a higher degree of genetic diversity among rod-shaped pLAB than cocci. Based on the LAB genetic analysis and specific probiotic selection criteria that involve beneficial properties, we sequenced 16 pLAB which were identified as Pediococcus pentosaceus, Enterococcus thailandicus, Lactobacillus pentosus/L. plantarum, L. brevis, and L. curvatus. Compatibility assays performed with cLAB and the 16 species described above indicate that all tested LAB can be included in a mixed probiotic formula. Based on our analyses, we suggest that E. gallinarum CRL 1826, L. garvieae CRL 1828, and P. pentosaceus 15 and 18B represent optimal probiotic candidates for Bd control and mitigation. © 2019 Niederle et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited149FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2016/25358-3This research was supported by Consejo Nacional de Investigaciones Científicas y Técnicas (PIP 063 to SEP), Consejo de Investigaciones de la Universidad Nacional de Tucumán (PIUNT 26/D 414 and 26/D 645 to SEP, and PIUNT 528), Agencia Nacional de Promoción Científica y Tecnológica (PICT 2017-2244 to SEP, PICT 2015-2467 to CEA, and PICT2017-4324 to MENM), Ministerio de Economía y Competitividad de España (CGL2015-70070-R to JB), Fondo Nacional de Desarrollo Científico y Tecnológico (1181758 to CSA and 3180107 to AVS), Fundação de Amparo à Pesquisa do Estado de São Paulo (2016/25358-3 to LFT). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscrip
Altered functional resting-state hypothalamic connectivity and abnormal pituitary morphology in children with Prader-Willi syndrome
Background: Prader-Willi syndrome (PWS) is a complex neurodevelopmental disorder, characterized by endocrine problems and hyperphagia, indicating hypothalamic-pituitary dysfunction. However, few studies have explored the underlying neurobiology of the hypothalamus and its functional connectivity with other brain regions. Thus, the aim of this study was to examine the anatomical differences of the hypothalamus, mammillary bodies, and pituitary gland as well as resting state functional connectivity of the hypothalamus in children with PWS. Methods: Twenty-seven children with PWS (13 DEL, 14 mUPD) and 28 typically developing children were included. Manual segmentations by a blinded investigator were performed to determine the volumes of the hypothalamus, mammillary bodies, and pituitary gland. In addition, brain-wide functional connectivity analysis was performed using the obtained masks of the hypothalamus. Results: Children with PWS showed altered resting state functional connectivity between hypothalamus and right and left lateral occipital complex, compared to healthy controls. In addition, children with PWS had on average a 50% smaller pituitary volume, an irregular shape of the pituitary, and a longer pituitary stalk. Pituitary volume did not increase in volume during puberty in PWS. No volumetric differences in the hypothalamus and mammillary bodies were found. In all subjects, the posterior pituitary bright spot was observed. Conclusions: We report altered functional hypothalamic connectivity with lateral occipital complexes in both hemispheres, which are implicated in response to food and reward system, and absence of connectivity might therefore at least partially contribute to the preoccupation with food in PWS
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Implementing evidence-based recommended practices for the management of patients with mild traumatic brain injuries in Australian emergency care departments: study protocol for a cluster randomised controlled trial
Background: Mild head injuries commonly present to emergency departments. The challenges facing clinicians in emergency departments include identifying which patients have traumatic brain injury, and which patients can safely be sent home. Traumatic brain injuries may exist with subtle symptoms or signs, but can still lead to adverse outcomes. Despite the existence of several high quality clinical practice guidelines, internationally and in Australia, research shows inconsistent implementation of these recommendations. The aim of this trial is to test the effectiveness of a targeted, theory- and evidence-informed implementation intervention to increase the uptake of three key clinical recommendations regarding the emergency department management of adult patients (18 years of age or older) who present following mild head injuries (concussion), compared with passive dissemination of these recommendations. The primary objective is to establish whether the intervention is effective in increasing the percentage of patients for which appropriate post-traumatic amnesia screening is performed.
Methods/design: The design of this study is a cluster randomised trial. We aim to include 34 Australian 24-hour emergency departments, which will be randomised to an intervention or control group. Control group departments will receive a copy of the most recent Australian evidence-based clinical practice guideline on the acute management of patients with mild head injuries. The intervention group will receive an implementation intervention based on an analysis of influencing factors, which include local stakeholder meetings, identification of nursing and medical opinion leaders in each site, a train-the-trainer day and standardised education and interactive workshops delivered by the opinion leaders during a 3 month period of time. Clinical practice outcomes will be collected retrospectively from medical records by independent chart auditors over the 2 month period following intervention delivery (patient level outcomes). In consenting hospitals, eligible patients will be recruited for a follow-up telephone interview conducted by trained researchers. A cost-effectiveness analysis and process evaluation using mixed-methods will be conducted. Sample size calculations are based on including 30 patients on average per department. Outcome assessors will be blinded to group allocation
Probing the Environment with Galaxy Dynamics
I present various projects to study the halo dynamics of elliptical galaxies.
This allows one to study the outer mass and orbital distributions of
ellipticals in different environments, and the inner distributions of groups
and clusters themselves.Comment: 5 pages, 2 figs, to appear in Proc. ESO Workshop, Groups of Galaxies
in the Nearby Universe (5-9 Dec 2005), eds. I. Saviane, V. Ivanov & J.
Borissova (Springer-Verlag
A systematic review of CBM professional development materials: are teachers receiving sufficient instruction in data-based decision-making?
Education and Child Studie
Critical Elements in Supergene Phosphates: The Example of the Weathering Profile at the Gavà Neolithic Mines, Catalonia, Spain
The essential role of Critical Elements (CE) in 21st century economy has led to an increasing demand of these metals and promotes the exploration of non-conventional deposits such as weathering profiles. The present work is focused on the study of a weathering profile located at the Archaeological Park of the Gavà Neolithic Mines, Barcelona, Catalonia, Spain. In the Gavà deposit, acid and oxidising meteoric fluids generated intense weathering during the early Pleistocene, affecting series of Llandoverian black shales and associated syn-sedimentary phosphates. The circulation of these acid fluids at deeper levels of the profile generated supergene vein-like mineralisations comprised of secondary phosphates (e.g., variscite, perhamite, crandallite, phosphosiderite) and sulphates (e.g., jarosite, alunite). This supergene mineralisation is significantly enriched in certain CE (e.g., Ga, Sc, REE, In, Co and Sb) that were mobilised from host rock components and later hosted in the crystal lattice of supergene minerals. Weathering processes and corresponding supergene enrichment of CE at the Gavà deposit could be used as an example to determine exploration guidelines of CE in weathering profiles and associated supergene phosphates worldwide
Particle Acceleration in Cosmic Sites - Astrophysics Issues in our Understanding of Cosmic Rays
Laboratory experiments to explore plasma conditions and stimulated particle
acceleration can illuminate aspects of the cosmic particle acceleration
process. Here we discuss the cosmic-ray candidate source object variety, and
what has been learned about their particle-acceleration characteristics. We
identify open issues as discussed among astrophysicists. -- The cosmic ray
differential intensity spectrum is a rather smooth power-law spectrum, with two
kinks at the "knee" (~10^15 eV) and at the "ankle" (~3 10^18 eV). It is unclear
if these kinks are related to boundaries between different dominating sources,
or rather related to characteristics of cosmic-ray propagation. We believe that
Galactic sources dominate up to 10^17 eV or even above, and the extragalactic
origin of cosmic rays at highest energies merges rather smoothly with Galactic
contributions throughout the 10^15--10^18 eV range. Pulsars and supernova
remnants are among the prime candidates for Galactic cosmic-ray production,
while nuclei of active galaxies are considered best candidates to produce
ultrahigh-energy cosmic rays of extragalactic origin. Acceleration processes
are related to shocks from violent ejections of matter from energetic sources
such as supernova explosions or matter accretion onto black holes. Details of
such acceleration are difficult, as relativistic particles modify the structure
of the shock, and simple approximations or perturbation calculations are
unsatisfactory. This is where laboratory plasma experiments are expected to
contribute, to enlighten the non-linear processes which occur under such
conditions.Comment: accepted for publication in EPJD, topical issue on Fundamental
physics and ultra-high laser fields. From review talk at "Extreme Light
Infrastructure" workshop, Sep 2008. Version-2 May 2009: adjust some wordings
and references at EPJD proofs stag
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