949 research outputs found
Honeypot-powered Malware Reverse Engineering
Honeypots, i.e. networked computer systems specially designed and crafted to
mimic the normal operations of other systems while capturing and storing
information about the interactions with the world outside, are a crucial
technology into the study of cyber threats and attacks that propagate and occur
through networks. Among them, high interaction honeypots are considered the
most efficient because the attacker (whether automated or not) perceives
realistic interactions with the target machine. In the case of automated
attacks, propagated by malwares, currently available honeypots alone are not
specialized enough to allow the analysis of their behaviors and effects on the
target system. The research presented in this paper shows how high interaction
honeypots can be enhanced by powering them with specific features that improve
the reverse engineering activities needed to effectively analyze captured
malicious entities
An Improved Model for Relativistic Solar Proton Acceleration applied to the 2005 January 20 and Earlier Events
This paper presents results on modelling the ground level response of the
higher energy protons for the 2005 January 20 ground level enhancement (GLE).
This event, known as GLE 69, produced the highest intensity of relativistic
solar particles since the famous event on 1956 February 23. The location of
recent X-ray and gamma-ray emission (N14 W61) was near to Sun-Earth connecting
magnetic field lines, thus providing the opportunity to directly observe the
acceleration source from Earth. We restrict our analysis to protons of energy
greater than 450 MeV to avoid complications arising from transport processes
that can affect the propagation of low energy protons. In light of this revised
approach we have reinvestigated two previous GLEs: those of 2000 July 14 (GLE
59) and 2001 April 15 (GLE 60). Within the limitations of the spectral forms
employed, we find that from the peak (06:55 UT) to the decline (07:30 UT)
phases of GLE 69, neutron monitor observations from 450 MeV to 10 GeV are best
fitted by the Gallegos-Cruz & Perez-Peraza stochastic acceleration model. In
contrast, the Ellison & Ramaty spectra did not fit the neutron monitor
observations as well. This result suggests that for GLE 69, a stochastic
process cannot be discounted as a mechanism for relativistic particle
acceleration, particularly during the initial stages of this solar event. For
GLE 59 we find evidence that more than one acceleration mechanism was present,
consistent with both shock and stochastic acceleration processes dominating at
different times of the event. For GLE 60 we find that Ellison & Ramaty spectra
better represent the neutron monitor observations compared to stochastic
acceleration spectra. The results for GLEs 59 and 60 are in agreement with our
previous work.Comment: 42 pages, 10 figures, 10 tables, published in ApJ, August 200
Relativistic Proton Production During the 14 July 2000 Solar Event: The Case for Multiple Source Mechanisms
Protons accelerated to relativistic energies by transient solar and
interplanetary phenomena caused a ground-level cosmic ray enhancement on 14
July 2000, Bastille Day. Near-Earth spacecraft measured the proton flux
directly and ground-based observatories measured the secondary responses to
higher energy protons. We have modelled the arrival of these relativistic
protons at Earth using a technique which deduces the spectrum, arrival
direction and anisotropy of the high-energy protons that produce increased
responses in neutron monitors. To investigate the acceleration processes
involved we have employed theoretical shock and stochastic acceleration
spectral forms in our fits to spacecraft and neutron monitor data. During the
rising phase of the event (10:45 UT and 10:50 UT) we find that the spectrum
between 140 MeV and 4 GeV is best fitted by a shock acceleration spectrum. In
contrast, the spectrum at the peak (10:55 UT and 11:00 UT) and in the declining
phase (11:40 UT) is best fitted with a stochastic acceleration spectrum. We
propose that at least two acceleration processes were responsible for the
production of relativistic protons during the Bastille Day solar event: (1)
protons were accelerated to relativistic energies by a shock, presumably a
coronal mass ejection (CME). (2) protons were also accelerated to relativistic
energies by stochastic processes initiated by magnetohydrodynamic (MHD)
turbulence.Comment: 38 pages, 9 figures, accepted for publication in the Astrophysical
Journal, January, 200
CD4 T lymphocyte autophagy is upregulated in the salivary glands of primary Sjögren’s syndrome patients and correlates with focus score and disease activity
Background: Primary Sjögren’s syndrome (pSS) is a common chronic autoimmune disease characterized by
lymphocytic infiltration of exocrine glands and peripheral lymphocyte perturbation. In the current study, we
aimed to investigate the possible pathogenic implication of autophagy in T lymphocytes in patients with pSS.
Methods: Thirty consecutive pSS patients were recruited together with 20 patients affected by sicca syndrome a
nd/or chronic sialoadenitis and 30 healthy controls. Disease activity and damage were evaluated according to SS
disease activity index, EULAR SS disease activity index, and SS disease damage index. T lymphocytes were analyzed
for the expression of autophagy-specific markers by biochemical, molecular, and histological assays in peripheral
blood and labial gland biopsies. Serum interleukin (IL)-23 and IL-21 levels were quantified by enzyme-linked
immunosorbent assay.
Results: Our study provides evidence for the first time that autophagy is upregulated in CD4+ T lymphocyte salivary
glands from pSS patients. Furthermore, a statistically significant correlation was detected between lymphocyte
autophagy levels, disease activity, and damage indexes. We also found a positive correlation between autophagy
enhancement and the increased salivary gland expression of IL-21 and IL-23, providing a further link between innate
and adaptive immune responses in pSS.
Conclusions: These findings suggest that CD4+ T lymphocyte autophagy could play a key role in pSS pathogenesis.
Additionally, our data highlight the potential exploitation of T cell autophagy as a biomarker of disease activity and
provide new ground to verify the therapeutic implications of autophagy as an innovative drug target in pSS
Ultrasound lung comets in systemic sclerosis: a chest sonography hallmark of pulmonary interstitial fibrosis
Objective. To assess the correlation between ultrasound lung comets (ULCs, a recently described echographic sign of interstitial lung fibrosis) and the current undisputed gold-standard high-resolution CT (HRCT) to detect pulmonary fibrosis in patients with SSc. Methods. We enrolled 33 consecutive SSc patients (mean age 5413 years, 30 females) in the Rheumatology Clinic of the University of Pisa. We assessed ULCs and chest HRCT within 1 week independently in all the patients. ULC score was obtained by summing the number of lung comets on the anterior and posterior chest. Pulmonary fibrosis was quantified by HRCT with a previously described 30-point Warrick score. Results. Presence of ULCs (defined as a total number more than 10) was observed in 17 (51%) SSc patients. Mean ULC score was 3750, higher in the diffuse than in the limited form (7366 vs 2135; P<0.05). A significant positive linear correlation was found between ULCs and Warrick scores (r?0.72; P<0.001). Conclusions. ULCs are often found in SSc, are more frequent in the diffuse than the limited form and are reasonably well correlated with HRCT-derived assessment of lung fibrosis. They represent a simple, bedside, radiation-free hallmark of pulmonary fibrosis of potential diagnostic and prognostic value
Physical activity but not sedentary activity is reduced in primary Sjögren’s syndrome
The aim of the study was to evaluate the levels of physical activity in individuals with primary Sjögren’s syndrome (PSS) and its relationship to the clinical features of PSS. To this cross-sectional study, self-reported levels of physical activity from 273 PSS patients were measured using the International Physical Activity Questionnaire-short form (IPAQ-SF) and were compared with healthy controls matched for age, sex and body mass index. Fatigue and other clinical aspects of PSS including disease status, dryness, daytime sleepiness, dysautonomia, anxiety and depression were assessed using validated tools. Individuals with PSS had significantly reduced levels of physical activity [median (interquartile range, IQR) 1572 (594–3158) versus 3708 (1732–8255) metabolic equivalent of task (MET) × min/week, p < 0.001], but similar levels of sedentary activity [median (IQR) min 300 (135–375) versus 343 (223–433) (MET) × min/week, p = 0.532] compared to healthy individuals. Differences in physical activity between PSS and controls increased at moderate [median (IQR) 0 (0–480) versus 1560 (570–3900) MET × min/week, p < 0.001] and vigorous intensities [median (IQR) 0 (0–480) versus 480 (0–1920) MET × min/week, p < 0.001]. Correlation analysis revealed a significant association between physical activity and fatigue, orthostatic intolerance, depressive symptoms and quality of life. Sedentary activity did not correlate with fatigue. Stepwise linear regression analysis identified symptoms of depression and daytime sleepiness as independent predictors of levels of physical activity. Physical activity is reduced in people with PSS and is associated with symptoms of depression and daytime sleepiness. Sedentary activity is not increased in PSS. Clinical care teams should explore the clinical utility of targeting low levels of physical activity in PSS
Observations of the December 13 and 14, 2006, Solar Particle Events in the 80 MeV/n - 3 GeV/n range from space with PAMELA detector
We present the space spectrometer PAMELA observations of proton and helium
fluxes during the December 13 and 14, 2006 solar particle events. This is the
first direct measurement of the solar energetic particles in space with a
single instrument in the energy range from 80 MeV/n up to 3
GeV/n. In the event of December 13 measured energy spectra of solar protons and
helium were compared with results obtained by neutron monitors and other
detectors. Our measurements show a spectral behaviour different from those
derived from the neutron monitor network. No satisfactory analytical fitting
was found for the energy spectra. During the first hours of the December 13
event solar energetic particles spectra were close to the exponential form
demonstrating rather significant temporal evolution. Solar He with energy up to
~1 GeV/n was recorded on December 13. In the event of December 14 energy of
solar protons reached ~600 MeV whereas maximum energy of He was below 100
MeV/n. The spectra were slightly bended in the lower energy range and preserved
their form during the second event. Difference in the particle flux appearance
and temporal evolution in these two events may argue for a special conditions
leading to acceleration of solar particles up to relativistic energies.Comment: Accepted for publication on Astrophysical journa
SOMA 2012. Identity and Connectivity. Proceedings of the 16th Symposium on Mediterranean Archaeology, Florence, Italy, 1–3 March 2012
Autonomic symptoms are common and are associated with overall symptom burden and disease activity in primary Sjögren's syndrome
Objectives - To determine the prevalence of autonomic dysfunction (dysautonomia) among patients with primary Sjögren's syndrome (PSS) and the relationships between dysautonomia and other clinical features of PSS.
Methods - Multicentre, prospective, cross-sectional study of a UK cohort of 317 patients with clinically well-characterised PSS. Symptoms of autonomic dysfunction were assessed using a validated instrument, the Composite Autonomic Symptom Scale (COMPASS). The data were compared with an age- and sex-matched cohort of 317 community controls. The relationships between symptoms of dysautonomia and various clinical features of PSS were analysed using regression analysis.
Results - COMPASS scores were significantly higher in patients with PSS than in age- and sex-matched community controls (median (IQR) 35.5 (20.9–46.0) vs 14.8 (4.4–30.2), p32.5, a cut-off value indicative of autonomic dysfunction. Furthermore, the COMPASS total score correlated independently with EULAR Sjögren's Syndrome Patient Reported Index (a composite measure of the overall burden of symptoms experienced by patients with PSS) (β=0.38, p<0.001) and disease activity measured using the EULAR Sjögren's Syndrome Disease Activity Index (β=0.13, p<0.009).
Conclusions - Autonomic symptoms are common among patients with PSS and may contribute to the overall burden of symptoms and link with systemic disease activity
Soluble P-selectin levels in synovial fluid and serum from patients with psoriatic arthritis
Objective: P-selectin is an adhesion molecule expressed by activated endothelial cells and platelets favouring the leukocyte adherence to microvascular endothelium. A soluble form of this molecule has been described, whose serum levels were found to be elevated and correlate with disease activity in rheumatoid arthritis (RA) patients. Aim of this study was to determine soluble P-selectin levels in synovial fluid (SF) and serum from patients with psoriatic arthritis (PsA), where it has never been investigated, to define its involvement in PsA synovial damage. Methods: we analysed, by ELISA, soluble P-selectin serum and SF levels in 100 patients presenting a knee joint effusion: 38 of them presented PsA, 40 RA and 22 osteoarthritis (OA). We examined the main clinical and laboratory parameters of these patients. Soluble P-selectin serum levels were also detected in 15 healthy subjects. Results: soluble P-selectin SF levels were significantly higher in PsA and RA patients respect to OA subjects. Soluble P-selectin SF levels were lower than those found in serum and the SF/serum ratio was higher in PsA and RA patients respect to OA. Soluble P-selectin serum levels were not significantly different among patients and controls. No correlation was found between SF and serum levels of soluble P-selectin and the main clinical parameters. Conclusions: our study of soluble P-selectin in PsA reveals a prominent local role of this molecule, with no differences respect to RA. Histological findings may be of help in understanding the role of this adhesion molecule in PsA
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