9,701 research outputs found
Atmospheric turbulence and superstatistics
Nonequilibrium systems with large-scale fluctuations of a suitable system
parameter are often effectively described by a superposition of two statistics,
a superstatistics. Here we illustrate this concept by analysing experimental
data of fluctuations in atmospheric wind velocity differences at Florence
airport.Comment: 9 pages, 4 figures. New version to appear in Europhysics News (2005
A new look at Sco OB1 association with Gaia DR2
We present and discuss photometric optical data in the area of the OB
association Sco OB1 covering about 1 squared degree. UBVI photometry is
employed in tandem with Gaia DR2 data to investigate the 3 dimensional
structure and the star formation history of the region. By combining parallaxes
and proper motions we identify 7 physical groups located between the young open
cluster NGC 6231 and the bright nebula IC4628. The most prominent group
coincides with the sparse open cluster Trumpler 24. We confirm the presence of
the intermediate age star cluster VdB-Hagen 202, which is unexpected in this
environment, and provide for the first time estimates of its fundamental
parameters. After assessing individual groups membership, we derive mean proper
motion components, distances, and ages. The seven groups belong to two
different families. To the younger family (family I) belong several pre-Main
Sequence stars as well. These are evenly spread across the field, and also in
front of VdB-Hagen 202. VdB-Hagen 202 and two smaller, slightly detached,
groups of similar properties form family II, which do not belong to the
association, but are caught in the act of passing through it. As for the
younger population, this forms an arc-like structure from the bright nebula IC
4628 down to NGC 6231, as previously found. Moreover, the pre-Main Sequence
stars density seems to increase from NGC 6231 northward to Trumpler 24
LHC discovery potential for models with continuously distributed mass
We study the Large Hadron Collider (LHC) discovery potential for models
with continuously distributed mass for and 14 TeV
centre-of-mass energies. One of possible LHC signatures for such models is the
existence of broad resonance in Drell-Yan reaction .Comment: 14 pages, some references and formula adde
Congenital muscular dystrophy: from muscle to brain.
Congenital muscular dystrophies (CMDs) are a wide group of muscular disorders that manifest with very early onset of muscular weakness, sometime associated to severe brain involvement.The histologic pattern of muscle anomalies is typical of dystrophic lesions but quite variable depending on the different stages and on the severity of the disorder.Recent classification of CMDs have been reported most of which based on the combination of clinical, biochemical, molecular and genetic findings, but genotype/phenotype correlation are in constant progression due to more diffuse utilization of the molecular analysis.In this article, the Authors report on CMDs belonging to the group of dystroglycanopathies and in particular on the most severe forms represented by the Fukuyama CMD, Muscle-Eye-Brain disease and Walker Walburg syndrome.Clinical diagnosis of infantile hypotonia is particularly difficult considering the different etiologic factors causing the lesions, the difficulty in localizing the involved CNS area (central vs. peripheral) and the limited role of the diagnostic procedures at this early age.The diagnostic evaluation is not easy mainly in differentiating the various types of CMDs, and represents a challenge for the neonatologists and pediatricians. Suggestions are reported on the way to reach a correct diagnosis with the appropriate use of the diagnostic means
A clinical review on megalencephaly: A large brain as a possible sign of cerebral impairment.
Megalencephaly and macrocephaly present with a head circumference measurement 2 standard deviations above the age-related mean. However, even if pathologic events resulting in both megalencephaly and macrocephaly may coexist, a distinction between these two entities is appropriate, as they represent clinical expression of different disorders with a different approach in clinical work-up, overall prognosis, and treatment. Megalencephaly defines an increased growth of cerebral structures related to dysfunctional anomalies during the various steps of brain development in the neuronal proliferation and/or migration phases or as a consequence of postnatal abnormal events. The disorders associated with megalencephaly are classically defined into 3 groups: idiopathic or benign, metabolic, and anatomic. In this article, we seek to underline the clinical aspect of megalencephaly, emphasizing the main disorders that manifest with this anomaly in an attempt to properly categorize these disorders within the megalencephaly group
t-channel production of heavy charged leptons
We study the pair production of heavy charged exotic leptons at e+ e-
colliders in the SU(2)_L x SU(2)_I x U(1)_Y model. This gauge group is a
subgroup of the grand unification group E6; SU(2)_I commutes with the electric
charge operator, and the three corresponding gauge bosons are electrically
neutral. In addition to the standard photon and Z boson contributions, we also
include the contributions from extra neutral gauge bosons. A t-channel
contribution due to W_I-boson exchange, which is unsuppressed by mixing angles,
is quite important. We calculate the left-right and forward-backward
asymmetries, and discuss how to differentiate different models.Comment: Increased discussion of experimental signatures. Version accepted by
PR
FIRST EVIDENCE OF OPUNTIA FICUS INDICA LEAVES USED AS SURFACE FINISHING TREATMENTS ON THE PIETRA LECCESE
Lecce stone belongs to the group of Miocene limestone and is distributed in many areas of
the Salento peninsula. The great part of the historical buildings, both religious and civil, in
this area have been constructed with this porous and soft material.
In the past, various methods and recipes have been used to protect the surfaces and ensure
their longevity. However, these ancient "recipes" are unidentified, because these techniques
were known only by the artisans who used them [2].
For this purpose, selected religious and civil buildings in the territory of the province of
Lecce, made of Lecce stone, not yet restored and possibly treated with some of these
unknown recipes because of their good conservation state, were studied and the presence
of surface treatments was investigated.
Samples were analysed by Py/GC-MS with and without thermally assisted hydrolysis and
methylation using tetramethylammonium hydroxide (TMAH). The results of the analyses
showed that these buildings have been protected with different natural products. Moreover,
for the first time, chemical biomarkers demonstrating the use of prickly pear leaves (Opuntia
ficus indica [3]) as protective surface finishes have been identified
pMSSM Benchmark Models for Snowmass 2013
We present several benchmark points in the phenomenological Minimal
Supersymmetric Standard Model (pMSSM). We select these models as experimentally
well-motivated examples of the MSSM which predict the observed Higgs mass and
dark matter relic density while evading the current LHC searches. We also use
benchmarks to generate spokes in parameter space by scaling the mass parameters
in a manner which keeps the Higgs mass and relic density approximately
constant.Comment: 10 pages, 6 figure
Searching For Anomalous Couplings
The capability of current and future measurements at low and high energy
colliders to probe for the existence of anomalous, CP conserving,
dipole moment-type couplings is examined. At present, constraints
on the universality of the tau charged and neutral current interactions as well
as the shape of the energy spectrum provide the strongest
bounds on such anomalous couplings. The presence of these dipole moments are
shown to influence, e.g., the extraction of from
decays and can lead to apparent violations of CVC expectations.Comment: 24 pages, 9 figure
INDUCTION PERIOD OF HETEROGENEOUS NUCLEATION DURING CRYSTALLISATION FOULING: ION IMPLANTATION EFFECTS
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