489 research outputs found
Neonatal stroke in premature neonates
There are many neuro-imaging studies on the presence of brain lesions in the preterm infant, using cranial ultrasound (cUS) and/or term equivalent age MRI (TEA-MRI). These studies however tend to focus on germinal matrix-intraventricular hemorrhage (GMH-IVH) and white matter injury. Data about perinatal arterial ischemic stroke (PAIS) or cerebral sinovenous thrombosis (CSVT) in the preterm infant are very limited. In fact, several large cohort studies on neuro-imaging in preterm infants do not even mention neonatal stroke.(1-4) Most studies about PAIS exclude preterm infants.(5) The aim of this review was to provide an update on neonatal stroke in the preterm infant, with a focus on neuro-imaging findings. (c) 2021 The Authors. Published by Elsevier Inc.Developmen
Oude koeienrassen op de reservebank
Lang niet iedereen is overtuigd van de hedendaagse melktypische Holstein-Friesian-koe. Volgens sommige veehouders moeten oude rassen in ere worden hersteld
Forecasting Human African Trypanosomiasis Prevalences from Population Screening Data Using Continuous Time Models
To eliminate and eradicate gambiense human African trypanosomiasis (HAT), maximizing the effectiveness of active case finding is of key importance. The progression of the epidemic is largely influenced by the planning of these operations. This paper introduces and analyzes five models for predicting HAT prevalence in a given village based on past observed prevalence levels and past screening activities in that village. Based on the quality of prevalence level predictions in 143 villages in Kwamouth (DRC), and based on the theoretical foundation underlying the models, we consider variants of the Logistic Model—a model inspired by the SIS epidemic model—to be most suitable for predicting HAT prevalence levels. Furthe
Taxonomy, nomenclature and phylogeny of three cladosporium-like hyphomycetes, Sorocybe resinae, Seifertia azaleae and the Hormoconis anamorph of Amorphotheca resinae
Using morphological characters, cultural characters, large subunit and
internal transcribed spacer rDNA (ITS) sequences, and provisions of the
International Code of Botanical Nomenclature, this paper attempts to resolve
the taxonomic and nomenclatural confusion surrounding three species of
cladosporium-like hyphomycetes. The type specimen of Hormodendrum
resinae, the basis for the use of the epithet resinae for the
creosote fungus {either as Hormoconis resinae or Cladosporium
resinae) represents the mononematous synanamorph of the synnematous,
resinicolous fungus Sorocybe resinae. The phylogenetic relationships
of the creosote fungus, which is the anamorph of Amorphotheca
resinae, are with the family Myxotrichaceae, whereas S.
resinae is related to Capronia (Chaetothyriales,
Herpotrichiellaceae). Our data support the segregation of
Pycnostysanus azaleae, the cause of bud blast of rhododendrons, in
the recently described anamorph genus Seifertia, distinct from
Sorocybe; this species is related to the Dothideomycetes but
its exact phylogenetic placement is uncertain. To formally stabilize the name
of the anamorph of the creosote fungus, conservation of Hormodendrum
resinae with a new holotype should be considered. The paraphyly of the
family Myxotrichaceae with the Amorphothecaceae suggested by
ITS sequences should be confirmed with additional genes
Tissue-Specific T2* Biomarkers in Patellar Tendinopathy by Subregional Quantification Using 3D Ultrashort Echo Time MRI
Background: Quantitative MRI of patellar tendinopathy (PT) can be challenging due to spatial variation of T2* relaxation times. Purpose: 1) To compare T2* quantification using a standard approach with analysis in specific tissue compartments of the patellar tendon. 2) To evaluate test–retest reliability of different methods for fitting ultrashort echo time (UTE)-relaxometry data. Study Type: Prospective. Subjects: Sixty-five athletes with PT. Field Strength/Sequence: 3D UTE scans covering the patellar tendon were acquired using a 3.0T scanner and a 16-channel surface coil. Assessment: Voxelwise median T2* was quantified with monoexponential, fractional-order, and biexponential fitting. We applied two methods for T2* analysis: first, a standard approach by analyzing all voxels covering the proximal patellar tendon. Second, within subregions of the patellar tendon, by using thresholds on biexponential fitting parameter percentage short T2* (0–30% for mostly long T2*, 30–60% for mixed T2*, and 60–100% for mostly short T2*). Statistical Tests: Average test–retest reliability was assessed in three athletes using coefficients-of-variation (CV) and coefficients-of-repeatability (CR). Results: With standard image analysis, we found a median [interquartile range, IQR] monoexponential T2* of 6.43 msec [4.32–8.55] and fractional order T2* 4.39 msec [3.06–5.78]. The percentage of short T2* components was 52.9% [35.5–69.6]. Subregional monoexponential T2* was 13.78 msec [12.11–16.46], 7.65 msec [6.49–8.61], and 3.05 msec [2.52–3.60] and fractional order T2* 11.82 msec [10.09–14.44], 5.14 msec [4.25–5.96], and 2.19 msec [1.82–2.64] for 0–30%, 30–60%, and 60–100% short T2*, respectively. Biexponential component short T2* was 1.693 msec [1.417–2.003] for tissue with mostly short T2* and long T2* of 15.79 msec [13.47–18.61] for mostly long T2*. The average CR (CV) was 2 msec (15%), 2 msec (19%) and 10% (22%) for monoexponential, fractional order and percentage short T2*, respectively. Data Conclusion: Patellar tendinopathy is characterized by regional variability in binding states of water. Quantitative multicompartment T2* analysis in PT can be facilitated using a voxel selection method based on using biexponential fitting parameters. Level of Evidence: 1. Technical Efficacy Stage: 1
Nuclear Shadowing in DIS: Numerical Solution of the Evolution Equation for the Green Function
Within a light-cone QCD formalism based on the Green function technique
incorporating color transparency and coherence length effects we study nuclear
shadowing in deep-inelastic scattering at moderately small Bjorken x_{Bj}.
Calculations performed so far were based only on approximations leading to an
analytical harmonic oscillatory form of the Green function. We present for the
first time an exact numerical solution of the evolution equation for the Green
function using realistic form of the dipole cross section and nuclear density
function. We compare numerical results for nuclear shadowing with previous
predictions and discuss differences.Comment: 21 pages including 3 figures; a small revision of the tex
The Glauber model and the heavy ion reaction cross section
We reexamine the Glauber model and calculate the total reaction cross section
as a function of energy in the low and intermediate energy range, where many of
the corrections in the model, are effective.
The most significant effect in this energy range is by the modification of
the trajectory due to the Coulomb field. The modification in the trajectory due
to nuclear field is also taken into account in a self consistent way.
The energy ranges in which particular corrections are effective, are
quantified and it is found that when the center of mass energy of the system
becomes 30 times the Coulomb barrier, none of the trajectory modification to
the Glauber model is really required.
The reaction cross sections for light and heavy systems, right from near
coulomb barrier to intermediate energies have been calculated. The exact
nuclear densities and free nucleon-nucleon (NN) cross sections have been used
in the calculations. The center of mass correction which is important for light
systems, has also been taken into account.
There is an excellent agreement between the calculations with the modified
Glauber model and the experimental data. This suggests that the heavy ion
reactions in this energy range can be explained by the Glauber model in terms
of free NN cross sections without incorporating any medium modification.Comment: RevTeX, 21 pages including 9 Postscript figures, submitted to Phys.
Rev.
Recommended from our members
Why Are People's Decisions Sometimes Worse with Computer Support?
In many applications of computerised decision support, a recognised source of undesired outcomes is operators' apparent over-reliance on automation. For instance, an operator may fail to react to a potentially dangerous situation because a computer fails to generate an alarm. However, the very use of terms like "over-reliance" betrays possible misunderstandings of these phenomena and their causes, which may lead to ineffective corrective action (e.g. training or procedures that do not counteract all the causes of the apparently "over-reliant" behaviour). We review relevant literature in the area of "automation bias" and describe the diverse mechanisms that may be involved in human errors when using computer support. We discuss these mechanisms, with reference to errors of omission when using "alerting systems", with the help of examples of novel counterintuitive findings we obtained from a case study in a health care application, as well as other examples from the literature
- …