1,361 research outputs found
Coronal radiation belts
The magnetic field of the solar corona has a large-scale dipole character,
which maps into the bipolar field in the solar wind. Using standard
representations of the coronal field, we show that high-energy ions can be
trapped stably in these large-scale closed fields. The drift shells that
describe the conservation of the third adiabatic invariant may have complicated
geometries. Particles trapped in these zones would resemble the Van Allen Belts
and could have detectable consequences. We discuss potential sources of trapped
particles
Functional changes in prefrontal cortex following frequency-specific training
Altres ajuts: European ANR (COEN4007-18, COEN-0003-01); PHRC grants from the French Ministry of Health and research funding; France Parkinson and ARSLA charity.Numerous studies indicate a significant role of pre-frontal circuits (PFC) connectivity involving attentional and reward neural networks within attention deficit hyperactivity disorder (ADHD) pathophysiology. To date, the neural mechanisms underlying the utility of non-invasive frequency-specific training systems in ADHD remediation remain underexplored. To address this issue, we created a portable electroencephalography (EEG)-based wireless system consisting of a novel headset, electrodes, and neuro program, named frequency specific cognitive training (FSCT). In a double-blind, randomized, controlled study we investigated the training effects in N = 46 school-age children ages 6-18 years with ADHD. 23 children in experimental group who underwent FCST training showed an increase in scholastic performance and meliorated their performance on neuropsychological tests associated with executive functions and memory. Their results were compared to 23 age-matched participants who underwent training with placebo (pFSCT). Electroencephalogram (EEG) data collected from participants trained with FSCT showed a significant increase in 14-18 Hz EEG frequencies in PFC brain regions, activities that indicated brain activation in frontal brain regions, the caudate nucleus, and putamen. These results demonstrate that FSCT targets specific prefrontal and striatal areas in children with ADHD, suggesting a beneficial modality for non-invasive modulation of brain areas implicated in attention and executive functions
3D photospheric velocity field of a Supergranular cell
We investigate the plasma flow properties inside a Supergranular (SG) cell,
in particular its interaction with small scale magnetic field structures. The
SG cell has been identified using the magnetic network (CaII wing brightness)
as proxy, applying the Two-Level Structure Tracking (TST) to high spatial,
spectral and temporal resolution observations obtained by IBIS. The full 3D
velocity vector field for the SG has been reconstructed at two different
photospheric heights. In order to strengthen our findings, we also computed the
mean radial flow of the SG by means of cork tracing. We also studied the
behaviour of the horizontal and Line of Sight plasma flow cospatial with
cluster of bright CaII structures of magnetic origin to better understand the
interaction between photospheric convection and small scale magnetic features.
The SG cell we investigated seems to be organized with an almost radial flow
from its centre to the border. The large scale divergence structure is probably
created by a compact region of constant up-flow close to the cell centre. On
the edge of the SG, isolated regions of strong convergent flow are nearby or
cospatial with extended clusters of bright CaII wing features forming the knots
of the magnetic network.Comment: 7 pages, submitted to A&A, referee's comments include
Complement Inhibition as a Proposed Neuroprotective Strategy following Cardiac Arrest
Out-of-hospital
cardiac arrest (OHCA) is a devastating disease
process with neurological injury accounting for
a disproportionate amount of the morbidity and
mortality following return of spontaneous
circulation. A dearth of effective treatment
strategies exists for global cerebral
ischemia-reperfusion (GCI/R) injury following
successful resuscitation from OHCA. Emerging
preclinical as well as recent human clinical
evidence suggests that activation of the
complement cascade plays a critical role in the
pathogenesis of GCI/R injury following OHCA. In
addition, it is well established that complement
inhibition improves outcome in both global and
focal models of brain ischemia. Due to the
profound impact of GCI/R injury following OHCA,
and the relative lack of effective
neuroprotective strategies for this pathologic
process, complement inhibition provides an
exciting opportunity to augment existing
treatments to improve patient outcomes. To this
end, this paper will explore the
pathophysiology of complement-mediated GCI/R
injury following OHCA
An In-Silico Pipeline for Rapid Screening of DNA Aptamers against Mycotoxins: The Case-Study of Fumonisin B1, Aflatoxin B1 and Ochratoxin A
Aptamers are single-stranded oligonucleotides selected by SELEX (Systematic Evolution of Ligands by EXponential Enrichment) able to discriminate target molecules with high affinity and specificity, even in the case of very closely related structures. Aptamers have been produced for several targets including small molecules like mycotoxins; however, the high affinity for their respective target molecules is a critical requirement. In the last decade, the screening through computational methods of aptamers for their affinity against specific targets has greatly increased and is becoming a commonly used procedure due to its convenience and low costs. This paper describes an in-silico approach for rapid screening of ten ssDNA aptamer sequences against fumonisin B1 (FB1, n = 3), aflatoxin B1 (AFB1, n = 2) and ochratoxin A (OTA, n = 5). Theoretical results were compared with those obtained by testing the same aptamers by fluorescent microscale thermophoresis and by magnetic beads assay for their binding affinity (KD) revealing a good agreement
Lipoprotein(a) Serum Levels Predict Pulse Wave Velocity in Subjects in Primary Prevention for Cardiovascular Disease with Large Apo(a) Isoforms: Data from the Brisighella Heart Study
In the last decades, high serum levels of lipoprotein(a) (Lp(a)) have been associated with increased cardiovascular disease (CVD) risk, in particular among individuals with smaller apolipoprotein(a) (apo(a)) isoforms than those with larger sizes. The aim of our analysis was to evaluate whether Lp(a) levels could predict early vascular aging, and whether smaller apo(a) isoforms had a predictive value for vascular aging different than larger apo(a) isoforms in a cohort of subjects free from CVD. We considered the data of a subset of Brisighella Heart Study (BHS) participants free from CVD (462 men and 516 women) who were clinically evaluated during the 2012 BHS population survey. Predictors of arterial stiffness, measured as carotid-femoral pulse wave velocity (cfPWV) were estimated by the application of a step-wise linear regression model. In our cohort, there were 511 subjects with small apo(a) size and 467 subjects with large apo(a) isoforms. Subjects with larger apo(a) isoform sizes had significantly lower serum levels of Lp(a). In the BHS subpopulation sample, cfPWV was predicted by age, systolic blood pressure (SBP), serum levels of high-density lipoprotein cholesterol (HDL-C), triglycerides (TG) and sex, higher HDL-C serum levels and female sex associated with lower values of cfPWV. In subjects with smaller apo(a) isoform sizes, predictors of cfPWV were age, SBP, sex and serum levels of HDL-C, being higher HDL-C serum levels and female sex associated to lower values of cfPWV. In subjects with larger apo(a) isoform sizes, cfPWV was predicted by age, SBP, serum levels of Lp(a) and sex, with female sex associated with lower values of cfPWV. In our subpopulation sample, Lp(a) did not predict cfPWV. However, in subjects with large apo(a) isoform sizes, Lp(a) was a significant predictor of arterial stiffness
Mesoscale flows in large aspect ratio simulations of turbulent compressible convection
We present the results of a very large aspect ratio (42.6) numerical
simulation of fully compressible turbulent convection in a polytropic
atmosphere, and focus on the properties of large-scale flows. Mesoscale
patterns dominate the turbulent energy spectrum. We show that these structures,
which had already been observed in Boussinesq simulations by Cattaneo et al.
(2001), have a genuine convective origin and do not result directly from
collective interactions of the smaller scales of the flow, even though their
growth is strongly affected by nonlinear transfers. If this result is relevant
to the solar photosphere, it suggests that the dominant convective mode below
the Sun's surface may be at mesoscales.Comment: 5 pages, 7 figures (reduced quality) -- published in A&A in 2005 but
not uploaded to the arxi
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