966 research outputs found
On coalescence as the origin of nuclei in hadronic collisions
The origin of weakly-bound nuclear clusters in hadronic collisions is a key
question to be addressed by heavy-ion collision (HIC) experiments. The measured
yields of clusters are approximately consistent with expectations from
phenomenological statistical hadronisation models (SHMs), but a theoretical
understanding of the dynamics of cluster formation prior to kinetic freeze out
is lacking. The competing model is nuclear coalescence, which attributes
cluster formation to the effect of final state interactions (FSI) during the
propagation of the nuclei from kinetic freeze out to the observer. This
phenomenon is closely related to the effect of FSI in imprinting femtoscopic
correlations between continuum pairs of particles at small relative momentum
difference. We give a concise theoretical derivation of the
coalescence--correlation relation, predicting nuclear cluster spectra from
femtoscopic measurements. We review the fact that coalescence derives from a
relativistic Bethe-Salpeter equation, and recall how effective quantum
mechanics controls the dynamics of cluster particles that are nonrelativistic
in the cluster centre of mass frame. We demonstrate that the
coalescence--correlation relation is roughly consistent with the observed
cluster spectra in systems ranging from PbPb to pPb and pp collisions. Paying
special attention to nuclear wave functions, we derive the coalescence
prediction for hypertriton and show that it, too, is roughly consistent with
the data. Our work motivates a combined experimental programme addressing
femtoscopy and cluster production under a unified framework. Upcoming pp, pPb
and peripheral PbPb data analysed within such a programme could stringently
test coalescence as the origin of clusters.Comment: 24 pages, 10 figure
Unitn-eprints: risultati di utilizzo, prospettive di sviluppo
The digital institutional archive Unitn-eprints, containing reserach outputs by the academic community of the University of Trento, was born in 2002. In this paper we analyze the software customization, some usage results and statistics, and its future perspectives and developments in connection with research evaluation systems
Unitn-eprints: risultati di utilizzo, prospettive di sviluppo
The digital institutional archive Unitn-eprints, containing reserach outputs by the academic community of the University of Trento, was born in 2002. In this paper we analyze the software customization, some usage results and statistics, and its future perspectives and developments in connection with research evaluation systems
Gait and Equilibrium in Subcortical Vascular Dementia
Subcortical vascular dementia is a clinical entity, widespread, even challenging to diagnose and correctly treat. Patients with this diagnosis are old, frail, often with concomitant pathologies, and therefore, with many drugs in therapy. We tried to diagnose and follow up for three years more than 600 patients. Study subjects were men and women, not bedridden, aged 68â94 years, outpatients, recruited from June, 1st 2007 to June, 1st 2010. We examined them clinically, neurologically, with specific consideration on drug therapies. Our aim has been to define gait and imbalance problem, if eventually coexistent with the pathology of white matter and/or with the worsening of the deterioration. Drug intake interference has been detected and considered
Small-angle neutron scattering and Molecular Dynamics structural study of gelling DNA nanostars
DNA oligomers with properly designed sequences self-assemble into well
defined constructs. Here, we exploit this methodology to produce bulk
quantities of tetravalent DNA nanostars (each one composed by 196 nucleotides)
and to explore the structural signatures of their aggregation process. We
report small-angle neutron scattering experiments focused on the evaluation of
both the form factor and the temperature evolution of the scattered intensity
at a nano star concentration where the system forms a tetravalent equilibrium
gel. We also perform molecular dynamics simulations of one isolated tetramer to
evaluate the form factor theoretically, without resorting to any approximate
shape. The numerical form factor is found to be in very good agreement with the
experimental one. Simulations predict an essentially temperature independent
form factor, offering the possibility to extract the effective structure factor
and its evolution during the equilibrium gelation.Comment: 9 pages, 5 figure
Postoperative delirium in kidney transplant patients
Delirium, also known as acute brain failure, is a medical condition characterized by recent onset of confusion, fluctuating awareness, disorganized thought, with memory and attention impairment. Post-operative delirium (POD) generally arises 1 to 3 days after surgery, in 25-37% of the hospitalized patients and in > 65% of those admitted to intensive care unit [1]
Increased age and male sex are independently associated with higher frequency of bloodâcerebrospinal fluid barrier dysfunction using the albumin quotient
Background: The cerebrospinal fluid (CSF)/serum quotient of albumin (QAlb) is the most used biomarker for the evaluation of bloodâcerebrospinal fluid barrier (B-CSF-B) permeability. For years QAlb was considered only as an age-related parameter but recently it has also been associated to sex. The aim of the present study was to explore the impact of sex in the determination of B-CSF-B dysfunction.
Methods: The analysis was retrospectively conducted on subjects consecutively admitted to the neurological ward. CSF and serum albumin levels were measured by immunonephelometry and pathological QAlb thresholds were considered: 6.5 under 40 years, 8.0 in the age 40â60 and 9.0 over 60 years.
Results: 1209 subjects were included in the study. 718 females and 491 males (age: 15â88 years): 24.6% of patients had a diagnosis of multiple sclerosis, 23.2% suffered from other inflammatory neurological diseases, 24.6% were affected by non-inflammatory neurological diseases, and for 27.6% of patients the final neurological diagnosis could not be traced. Dysfunctional B-CSF-B was detected more frequently (44 vs. 20.1%, p < 0.0001) and median QAlb value were higher (7.18 vs. 4.87, p < 0.0001) in males than in females in the overall study population and in all disease sub- groups. QAlb and age were positively correlated both in female (p < 0.0001) and male (p < 0.0001) patients, however the slopes of the two regression lines were not significantly different (p = 0.7149), while the difference between the elevations was extremely significant (p < 0.0001) with a gap of 2.2 units between the two sexes. Finally, in a multivari- able linear regression analysis increased age and male sex were independently associated with higher QAlb in the overall study population (both p < 0.001) and after stratification by age and disease group.
Conclusions: Accordingly, identification and validation of sex-targeted QAlb thresholds should be considered as a novel tool in an effort to achieve more precision in the medical approach
Novel parameter-free coalescence model for deuteron production
A microscopic understanding of (anti)deuteron production in hadron-hadron
collisions is the subject of many experimental and theoretical efforts in
nuclear physics. This topic is also very relevant for astrophysics, since the
rare production of antinuclei in our Universe could be a doorway to discover
new physics. In this work, we describe a new coalescence afterburner for event
generators based on the Wigner function formalism and we apply it to the
(anti)deuteron case, taking into account a realistic particle emitting source.
The model performance is validated using the EPOS and PYTHIA event generators
applied to proton-proton collisions at the centre-of-mass energy 13
TeV, triggered for high multiplicity events, and the experimental data measured
by ALICE in the same collision system. The model relies on the direct
measurement of the particle emitting source carried out by means of
nucleon-nucleon femtoscopic correlations in the same collision system and
energy. The resulting parameter-free model is used to predict deuteron
differential spectra assuming different deuteron wavefunctions within the
Wigner function formalism. The predicted deuteron spectra show a clear
sensitivity to the choice of the deuteron wavefunction. The Argonne
wavefunction provides the best description of the experimental data. This model
can now be used to study the production of (anti)deuterons over a wide range of
collision energies and be extended to heavier nuclei.Comment: 13 pages, 9 Figures, submitted to PR
Elective Endovascular Aneurysm Repair (EVAR) for the Treatment of Infrarenal Abdominal Aortic Aneurysms of 5.0â5.5 cm: Differences between Men and Women
Background: There is significant debate regarding the existence of sex-related differences in the presentation, treatment, and outcomes of men versus women affected by abdominal aortic aneurysm (AAA). The purpose of this study is to compare endovascular aneurysm repair (EVAR) of infrarenal AAAs with the current sex-neutral 5.0â5.5 cm-diameter threshold for intervention between the two sexes. Methods: Retrospective review of consecutive cases from a single teaching institution over a period of five years of patients who had undergone elective EVAR for AAAs between 5.0 and 5.5 cm in diameter. Outcomes of interest were compared according to sex. Results: Ninety-four patients were included in the analysis, with a higher prevalence of men (53%). Females were older at the time of repair, 78 ± 5.1 years, versus 71.7 ± 7 years (p < 0.01), and had higher incidence of underlying comorbidities, namely, arrhythmia, chronic kidney disease, and previous carotid revascularization. Women had higher incidence of immediate systemic complications (p = 0.021), post-operative AMI (p = 0.001), arrhythmia (p = 0.006), pulmonary oedema (p < 0.001), and persistent renal dysfunction (p = 0.029). Multivariate analysis for post-operative factors associated to mortality and adjusted for sex confirmed that AMI (p = 0.015), arrhythmia (p = 0.049), pulmonary oedema (p = 0.015), persistent renal dysfunction (p < 0.001), cerebral ischemia (p < 0.001), arterial embolism of lower limbs (p < 0.001), and deep-vein thrombosis of lower limbs (p < 0.001) were associate to higher EVAR-related mortality; a higher incidence of post-operative AMI (p = 0.014), pulmonary edema (p = 0.034), and arterial embolism of lower limbs (p = 0.046) were associated to higher 30-days mortality. In females there was also a higher rate of suprarenal fixation (p = 0.026), insertion outside the instruction for use (p = 0.035), and a more hostile neck anatomy with different proximal aortic diameter (p < 0.001) and angle (p = 0.003). Conclusions: A similar threshold of size of AAA for elective surgery for both males and females might not be appropriate for surgical intervention, as females tend to have worse outcomes. Further population-based studies are needed to guide on sex-related differences and intervention on AAA
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