3,830 research outputs found
Testosterone insulin-like effects: an in vitro study on the short-term metabolic effects of testosterone in human skeletal muscle cells
Testosterone by promoting different metabolic pathways contributes to short-term homeostasis of skeletal muscle, the largest insulin-sensitive tissue and the primary site for insulin-stimulated glucose utilization. Despite evidences indicate a close relationship between testosterone and glucose metabolism, the molecular mechanisms responsible for a possible testosterone-mediated insulin-like effects on skeletal muscle are still unknown
Surgical Treatment for a Relapsing Malleolar Bursitis in a Professional Figure Skating: Case Report
The increase of popularity in sports as Roller Skating, Figure Skating and Ice Hockey has simultaneously increased the number of skating-related injuries. Lesions of chronic dermatological nature and muscle and tendon lesions have high number of case reports. Ankle and foot are peculiarly involved and this condition suggests the correlation with the use of the skating boot, which with its high-cut and hard-fit changes the joint biomechanics and function and, as a result, the intergumentary system is continuously damaged by the compression and rubbing on the foot. The frequent onset of non-septic chronic relapsing bursitis at the level of the malleolar region is common in all sports requiring the use of skating boots. The conservative treatment is usually compromised by the repetition of the traumatic event due to the use of the skating boot. The case report of a 19 year old professional figure skater affected by non-septic relapsing malleolar bursitis at the level of the malleolar region is presented
Power-Law Time Distribution of Large Earthquakes
We study the statistical properties of time distribution of seimicity in
California by means of a new method of analysis, the Diffusion Entropy. We find
that the distribution of time intervals between a large earthquake (the main
shock of a given seismic sequence) and the next one does not obey Poisson
statistics, as assumed by the current models. We prove that this distribution
is an inverse power law with an exponent . We propose the
Long-Range model, reproducing the main properties of the diffusion entropy and
describing the seismic triggering mechanisms induced by large earthquakes.Comment: 4 pages, 3 figures. Revised version accepted for publication. Typos
corrected, more detailed discussion on the method used, refs added. Phys.
Rev. Lett. (2003) in pres
Impact of migraine on fibromyalgia symptoms
Background: Fibromyalgia (FMS) and high frequency episodic/chronic migraine (M) very frequently co-occur, suggesting common pathophysiological mechanisms; both conditions display generalized somatic hyperalgesia. In FMS-M comorbidity we assessed if: a different level of hyperalgesia is present compared to one condition only; hyperalgesia is a function of migraine frequency; migraine attacks trigger FMS symptoms. Methods: Female patients with fibromyalgia (FMS)(n.40), high frequency episodic migraine (M1)(n.41), chronic migraine (M2)(n.40), FMS + M1 (n.42) and FMS + M2 (n.40) underwent recording of: −electrical pain thresholds in skin, subcutis and muscle and pressure pain thresholds in control sites, −pressure pain thresholds in tender points (TePs), −number of monthly migraine attacks and fibromyalgia flares (3-month diary). Migraine and FMS parameters were evaluated before and after migraine prophylaxis, or no prophylaxis, for 3 months with calcium-channel blockers, in two further FMS + H1 groups (n.49, n.39). 1-way ANOVA was applied to test trends among groups, Student’s t-test for paired samples was used to compare pre and post-treatment values. Results: The lowest electrical and pressure thresholds at all sites and tissues were found in FMS + M2, followed by FMS + H1, FMS, M2 and M1 (trend: p < 0.0001). FMS monthly flares were progressively higher in FMS, FMS + M1 and FMS + M2 (p < 0.0001); most flares (86–87 %) occurred within 12 h from a migraine attack in co-morbid patients (p < 0.0001). Effective migraine prophylaxis vs no prophylaxis also produced a significant improvement of FMS symptoms (decreased monthly flares, increased pain thresholds)(0.0001 < p < 0.003). Conclusions: Co-morbidity between fibromyalgia and migraine involves heightened somatic hyperalgesia compared to one condition only. Increased migraine frequency – with shift towards chronicity – enhances both hyperalgesia and spontaneous FMS pain, which is reversed by effective migraine prophylaxis. These results suggest different levels of central sensitization in patients with migraine, fibromyalgia or both conditions and a role for migraine as a triggering factor for FMS
Crossover scaling from classical to nonclassical critical behavior
We study the crossover between classical and nonclassical critical behaviors.
The critical crossover limit is driven by the Ginzburg number G. The
corresponding scaling functions are universal with respect to any possible
microscopic mechanism which can vary G, such as changing the range or the
strength of the interactions. The critical crossover describes the unique flow
from the unstable Gaussian to the stable nonclassical fixed point. The scaling
functions are related to the continuum renormalization-group functions. We show
these features explicitly in the large-N limit of the O(N) phi^4 model. We also
show that the effective susceptibility exponent is nonmonotonic in the
low-temperature phase of the three-dimensional Ising model.Comment: 5 pages, final version to appear in Phys. Rev.
The interstellar medium and feedback in the progenitors of the compact passive galaxies at z~2
Quenched galaxies at z>2 are nearly all very compact relative to z~0,
suggesting a physical connection between high stellar density and efficient,
rapid cessation of star-formation. We present restframe UV spectra of
Lyman-break galaxies (LBGs) at z~3 selected to be candidate progenitors of
quenched galaxies at z~2 based on their compact restframe optical sizes and
high surface density of star-formation. We compare their UV properties to those
of more extended LBGs of similar mass and star formation rate (non-candidates).
We find that candidate progenitors have faster ISM gas velocities and higher
equivalent widths of interstellar absorption lines, implying larger velocity
spread among absorbing clouds. Candidates deviate from the relationship between
equivalent widths of Lyman-alpha and interstellar absorption lines in that
their Lyman-alpha emission remains strong despite high interstellar absorption,
possibly indicating that the neutral HI fraction is patchy such that
Lyman-alpha photons can escape. We detect stronger CIV P-Cygni features
(emission and absorption) and HeII emission in candidates, indicative of larger
populations of metal rich Wolf-Rayet stars compared to non-candidates. The
faster bulk motions, broader spread of gas velocity, and Lyman-alpha properties
of candidates are consistent with their ISM being subject to more energetic
feedback than non-candidates. Together with their larger metallicity (implying
more evolved star-formation activity) this leads us to propose, if
speculatively, that they are likely to quench sooner than non-candidates,
supporting the validity of selection criteria used to identify them as
progenitors of z~2 passive galaxies. We propose that massive, compact galaxies
undergo more rapid growth of stellar mass content, perhaps because the gas
accretion mechanisms are different, and quench sooner than normally-sized LBGs
at these early epochs.Comment: Accepted for publication in the Astrophysical Journa
A variable absorption feature in the X-ray spectrum of a magnetar
Soft gamma-ray repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are slowly
rotating, isolated neutron stars that sporadically undergo episodes of
long-term flux enhancement (outbursts) generally accompanied by the emission of
short bursts of hard X-rays. This behaviour can be understood in the magnetar
model, according to which these sources are mainly powered by their own
magnetic energy. This is supported by the fact that the magnetic fields
inferred from several observed properties of AXPs and SGRs are greater than -
or at the high end of the range of - those of radio pulsars. In the peculiar
case of SGR 0418+5729, a weak dipole magnetic moment is derived from its timing
parameters, whereas a strong field has been proposed to reside in the stellar
interior and in multipole components on the surface. Here we show that the
X-ray spectrum of SGR 0418+5729 has an absorption line, the properties of which
depend strongly on the star's rotational phase. This line is interpreted as a
proton cyclotron feature and its energy implies a magnetic field ranging from
2E14 gauss to more than 1E15 gauss.Comment: Nature, 500, 312 (including Supplementary Information
Rapidly rotating second-generation progenitors for the blue hook stars of {\omega} Cen
Horizontal Branch stars belong to an advanced stage in the evolution of the
oldest stellar galactic population, occurring either as field halo stars or
grouped in globular clusters. The discovery of multiple populations in these
clusters, that were previously believed to have single populations gave rise to
the currently accepted theory that the hottest horizontal branch members (the
blue hook stars, which had late helium-core flash ignition, followed by deep
mixing) are the progeny of a helium-rich "second generation" of stars. It is
not known why such a supposedly rare event (a late flash followed by mixing) is
so common that the blue hook of {\omega} Cen contains \sim 30% of horizontal
branch stars 10 , or why the blue hook luminosity range in this massive cluster
cannot be reproduced by models. Here we report that the presence of helium core
masses up to \sim 0.04 solar masses larger than the core mass resulting from
evolution is required to solve the luminosity range problem. We model this by
taking into account the dispersion in rotation rates achieved by the
progenitors, whose premain sequence accretion disc suffered an early disruption
in the dense environment of the cluster's central regions where
second-generation stars form. Rotation may also account for frequent
late-flash-mixing events in massive globular clusters.Comment: 44 pages, 8 figures, 2 tables in Nature, online june 22, 201
Mesoscopic 3D Charge Transport in Solution-Processed Graphene-Based Thin Films: A Multiscale Analysis
Graphene and related 2D material (GRM) thin films consist of 3D assembly of billions of 2D nanosheets randomly distributed and interacting via van der Waals forces. Their complexity and the multiscale nature yield a wide variety of electrical characteristics ranging from doped semiconductor to glassy metals depending on the crystalline quality of the nanosheets, their specific structural organization ant the operating temperature. Here, the charge transport (CT) mechanisms are studied that are occurring in GRM thin films near the metal-insulator transition (MIT) highlighting the role of defect density and local arrangement of the nanosheets. Two prototypical nanosheet types are compared, i.e., 2D reduced graphene oxide and few-layer-thick electrochemically exfoliated graphene flakes, forming thin films with comparable composition, morphology and room temperature conductivity, but different defect density and crystallinity. By investigating their structure, morphology, and the dependence of their electrical conductivity on temperature, noise and magnetic-field, a general model is developed describing the multiscale nature of CT in GRM thin films in terms of hopping among mesoscopic bricks, i.e., grains. The results suggest a general approach to describe disordered van der Waals thin films
EO-ALERT: A Novel Architecture for the Next Generation of Earth Observation Satellites Supporting Rapid Civil Alerts
Satellite Earth Observation (EO) data is ubiquitously used in many applications, providing basic services to
society, such as environment monitoring, emergency management and civilian security. Due to the increasing request
of EO products by the market, the classical EO data chain generates a severe bottleneck problem, further exacerbated
in constellations. A huge amount of EO raw data generated on-board the satellite must be transferred to ground,
slowing down the EO product availability, increasing latency, and hampering the growth of applications in
accordance with the increased user demand.
This paper provides an overview of the results achieved by the EO-ALERT project (http://eo-alert-h2020.eu/), an
H2020 European Union research activity led by DEIMOS Space. EO-ALERT proposes the definition and
development of the next-generation EO data processing chain, based on a novel flight segment architecture that
moves optimised key EO data processing elements from the ground segment to on-board the satellite, with the aim of
delivering the EO products to the end user with very low latency (quasi-real-time). EO-ALERT achieves, globally,
latencies below five minutes for EO products delivery, reaching latencies below 1 minute in some scenarios.
The proposed architecture solves the above challenges through a combination of innovations in the on-board
elements of the data chain and the communications. Namely, the architecture introduces innovative technological
solutions, including on-board reconfigurable data handling, on-board image generation and processing for the
generation of alerts (EO products) using Artificial Intelligence (AI), on-board data compression and encryption using
AI, high-speed on-board avionics, and reconfigurable high data rate communication links to ground, including a
separate chain for alerts with minimum latency and global coverage.
The paper presents the proposed architecture, its performance and hardware, considering two different user
scenarios; ship detection and extreme weather observation/nowcasting. The results show that, when implemented
using COTS components and available communication links, the proposed architecture can deliver alerts to ground
with latency lower than five minutes, for both SAR and Optical missions, demonstrating the viability of the EOALERT
concept and architecture. The paper also discusses the implementation on an avionics test bench for
testing the architecture with real EO data, with the aim of demonstrating that it can meet the requirements of the
considered scenarios in terms of detection performance and provides technologies at a high TRL (4-5). When
proven, this will open unprecedented opportunities for the exploitation of civil EO products, especially in latency
sensitive scenarios, such as disaster management
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