1,066 research outputs found
Pathomorphological and CT-angiographical characteristics of coronary atherosclerotic plaques in cases of sudden cardiac death.
The goal of this study was to assess the localization and types of thrombosed plaques in cases of sudden cardiac death attributed to coronary artery disease and to evaluate possible correlations with body mass index (BMI) and increased heart weight. This retrospective study was performed on forensic cases for which the cause of death was attributed to coronary artery disease. A complete autopsy and a multi-phase postmortem computed tomography (CT) angiography (MPMCTA) were performed in all cases. Eighty-five cases were selected (mean age, 55.18 ± 11.04 years; 72 men and 13 women). MPMCTA performed prior to autopsy enabled an evaluation of coronary artery perfusion before dissection of the body and helped therefore to guide sampling for histology. An acute coronary thrombosis was found in 57 cases, which included plaque erosion in 26 cases (mean age, 46.73 ± 8.33 years) and rupture or intra-plaque hemorrhage in 31 cases (mean age, 58.23 ± 10.62 years). Erosions were most frequently found in the left anterior descending artery (61.5%), while only 35.48% of ruptures were observed in this artery. Chronic coronary pathology was considered as the main cause of death in 28 cases (mean age, 59.64 ± 9.47 years). Sixty-two of the cases (72.94%) had a BMI in the overweight category (BMI ≥25), with the highest mean BMI in patients with chronic coronary pathology without acute thrombosis found at autopsy. The heart weight was above the predicted reference values in 52 cases (61.18%). Our results are in accordance with previously published studies on the spatial distribution of vulnerable plaques. We observed a higher percentage of eroded plaques than previously reported. Patients with coronary erosions were significantly younger than those with plaque rupture or those without an acute coronary thrombosis (p values <0.0001). BMI and heart weight were significantly higher for cases without thrombosis in comparison with those with plaque rupture (p values 0.028 and 0.003, respectively). Our results indicating that increased BMI and overweight hearts are associated with chronic ischemic heart disease are compatible with clinical studies. Performing more postmortem studies on forensic autopsies, including modern radiological examinations with MPMCTA, can enhance the detection of vulnerable plaques in living patients and prevent sudden cardiac death
Recent developments from the loop-tree duality
In this talk, we review the most recent developments of the four-dimensional
unsubstraction (FDU) and loop-tree duality (LTD) methods. In particular, we
make emphasis on the advantages of the LTD formalism regarding asymptotic
expansions of loop integrands.Comment: 8 pages, 1 figure. Presented at 13th International Symposium on
Radiative Corrections RADCOR2017, 24-29 September 2017, St. Gilgen, Austri
On the interplay between the loop-tree duality and helicity amplitudes
The spinor-helicity formalism has proven to be very efficient in the
calculation of scattering amplitudes in quantum field theory, while the loop
tree duality (LTD) representation of multi-loop integrals exhibits appealing
and interesting advantages with respect to other approaches. In view of the
most recent developments in LTD, we exploit the synergies with the
spinor-helicity formalism to analyse illustrative one- and two-loop scattering
processes. We focus our discussion on the local UV renormalisation of IR and UV
finite amplitudes and present a fully automated numerical implementation that
provides efficient expressions which are integrable directly in four space-time
dimensions.Comment: 12 pages, 5 figures. In v2: discussion on the application of two-loop
local renormalisation added; references update
Hearing faces: how the infant brain matches the face it sees with the speech it hears
Speech is not a purely auditory signal. From around 2 months of age, infants are able to correctly match the vowel they hear with the appropriate articulating face. However, there is no behavioral evidence of integrated audiovisual perception until 4 months of age, at the earliest, when an illusory percept can be created by the fusion of the auditory stimulus and of the facial cues (McGurk effect). To understand how infants initially match the articulatory movements they see with the sounds they hear, we recorded high-density ERPs in response to auditory vowels that followed a congruent or incongruent silently articulating face in 10-week-old infants. In a first experiment, we determined that auditory–visual integration occurs during the early stages of perception as in adults. The mismatch response was similar in timing and in topography whether the preceding vowels were presented visually or aurally. In the second experiment, we studied audiovisual integration in the linguistic (vowel perception) and nonlinguistic (gender perception) domain. We observed a mismatch response for both types of change at similar latencies. Their topographies were significantly different demonstrating that cross-modal integration of these features is computed in parallel by two different networks. Indeed, brain source modeling revealed that phoneme and gender computations were lateralized toward the left and toward the right hemisphere, respectively, suggesting that each hemisphere possesses an early processing bias. We also observed repetition suppression in temporal regions and repetition enhancement in frontal regions. These results underscore how complex and structured is the human cortical organization which sustains communication from the first weeks of life on
LASSO experiment: Intercalibrations of the LASSO ranging stations
Presented are equations for time synchronization of laser ranging stations. The system consists of a satellite fitted with laser retroreflectors associated to a light detector and an event timer and two laser ranging stations with their own event timers. Methods of determining the Lasso intercalibration constant are given
Mapping the Early Cortical Folding Process in the Preterm Newborn Brain
In the developing human brain, the cortical sulci formation is a complex process starting from 14 weeks of gestation onward. The potential influence of underlying mechanisms (genetic, epigenetic, mechanical or environmental) is still poorly understood, because reliable quantification in vivo of the early folding is lacking. In this study, we investigate the sulcal emergence noninvasively in 35 preterm newborns, by applying dedicated postprocessing tools to magnetic resonance images acquired shortly after birth over a developmental period critical for the human cortex maturation (26-36 weeks of age). Through the original three-dimensional reconstruction of the interface between developing cortex and white matter and correlation with volumetric measurements, we document early sulcation in vivo, and quantify changes with age, gender, and the presence of small white matter lesions. We observe a trend towards lower cortical surface, smaller cortex, and white matter volumes, but equivalent sulcation in females compared with males. By precisely mapping the sulci, we highlight interindividual variability in time appearance and interhemispherical asymmetries, with a larger right superior temporal sulcus than the left. Thus, such an approach, included in a longitudinal follow-up, may provide early indicators on the structural basis of cortical functional specialization and abnormalities induced by genetic and environmental factor
The Nuclear Yukawa Model on a Lattice
We present the results of the quantum field theory approach to nuclear Yukawa
model obtained by standard lattice techniques. We have considered the simplest
case of two identical fermions interacting via a scalar meson exchange.
Calculations have been performed using Wilson fermions in the quenched
approximation. We found the existence of a critical coupling constant above
which the model cannot be numerically solved. The range of the accessible
coupling constants is below the threshold value for producing two-body bound
states. Two-body scattering lengths have been obtained and compared to the non
relativistic results.Comment: 15 page
Manifestation of three-body forces in three-body Bethe-Salpeter and light-front equations
Bethe-Salpeter and light-front bound state equations for three scalar
particles interacting by scalar exchange-bosons are solved in ladder
truncation. In contrast to two-body systems, the three-body binding energies
obtained in these two approaches differ significantly from each other: the
ladder kernel in light-front dynamics underbinds by approximately a factor of
two compared to the ladder Bethe-Salpeter equation. By taking into account
three-body forces in the light-front approach, generated by two exchange-bosons
in flight, we find that most of this difference disappears; for small exchange
masses, the obtained binding energies coincide with each other.Comment: 24 pages, 8 figures, submitted in Few-Body System
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