551 research outputs found
Geomorphological and geochemical characterization of the 11 August 2008 mud volcano eruption at S. Barbara village (Sicily, Italy) and its possible relationship with seismic activity
On 11 August 2008 a paroxysmal eruption occurred at Santa Barbara mud volcano (MV), located close to Caltanissetta, one of the most densely populated cities of Sicily (Italy). An associated minor event took place on August 2009. Both the events caused severe damage to civil infrastructures located within a range of about 2 km from the eruptive vent. Geomorphological, geochemical, and seismological investigations were carried out for framing the events in the appropriate geodynamic context. Geomorphological surveys recognized, in the immediate surrounding of the main emission point, two different families of processes and landforms: (i) ground deformations and (ii) changes in morphology and number of the fluid emitting vents. These processes were associated to a wider network of fractures, seemingly generated by the shock wave produced by the gas blast that occurred at the main paroxysm. Geochemical characterization allowed an estimation of the source of the fluids, or at least their last standing, at about 3 km depth. Finally, the close time relationships observed between anomalous increments of seismic activity and the two main paroxysmal events accounted for a possible common trigger for both the phenomena, even with different timing due to the very different initial conditions and characteristics of the two processes, i.e. seismogenesis and gas overloading
Central extensions, classical non-equivariant maps and residual symmetries
The arising of central extensions is discussed in two contexts. At first
classical counterparts of quantum anomalies (deserving being named as
"classical anomalies") are associated with a peculiar subclass of the
non-equivariant maps. Further, the notion of "residual symmetry" for theories
formulated in given non-vanishing EM backgrounds is introduced. It is pointed
out that this is a Lie-algebraic, model-independent, concept.Comment: 8 pages, LaTex. Talk given at the International Conference
"Renormalization Group and Anomalies in Gravitation and Cosmology", Ouro
Preto, Brazil, March 2003. To appear in the Proceeding
The use of non-invasive field techniques in the study of small topographically closed lakes: two case studies in Sicily (Italy)
Small endhoreic (topografically closed) lakes represent a little percentage
of continental waters but, in arid or sub-arid regions, they develop special
ecosystems potentially prone to ecological involution due to climatic
changes. The mandatory use of light, non-invasive field techniques is
often required, especially in protected areas. In the present work the use
of non-invasive techniques like GPSâbased bathymetric and photographic
surveys have been applied to the study of two lakes, Specchio di
Venere and Sfondato (Sicily, southern Italy), both natural reserves. The
comparison between historical surveys and modern GPSâbased bathymetries
highlighted the difficulty of using the former for the reconstruction
of climatic-induced variations due to the low number of
measurements (spatial aliasing). In particular, at the intracaldera Lake
Specchio di Venere, a high resolution survey gave new insights into a peculiar
geo-ecosystem whose evolution is driven by both volcanic phenomena
and biomineralization processes. On the contrary, the morphology
of Lake Sfondato floor is much more simple and driven only by the superimposition
of a detrital sedimentation on the initial collapse that generated
the lake. The comparison betweem direct measurements and
estimated changes of lake level, carried out between February 2008 and
October 2009 variations, allowed us to test different hypotheses of hydrological
balances, leading to opposite conclusions with respect to previous
studies and remarking the fundamental importance of direct
measurements in the validation of theoretical hydrological models
Geomorphological and geochemical characterization of the August 11, 2008 mud volcano eruption at S. Barbara village (Sicily, Italy) and its possible relationship with seismic activity
On August 11, 2008 a paroxysmal eruption occurred at Santa Barbara mud volcano (MV), located close to Caltanissetta, one of the most densely populated cities of Sicily (Italy). An associated minor event took place on August, 2009. Both the events caused severe damages to civil infrastructures located within a range of about 2 km from the eruptive vent. Geomorphological, geochemical and seismological investigations were carried out for framing the events in the appropriate geodynamic context. Geomorphological surveys recognized, in the immediate surrounding of the main emission point, two different families of processes and landforms: ground deformations and changes in morphology and number of the fluid emitting vents. These processes were associated to a wider network of fractures, seemingly generated by the shock wave produced by the gas blast occurred at the main paroxysm. Geochemical characterization allowed to estimate the source of the fluids, or at least their last standing, at about 3 km depth. Finally, the close time relationships observed between anomalous increments of seismic activity and the two main paroxysmal events, accounted for a common possible trigger for both the phenomena, even if with a different timing due to the very different initial conditions and characteristics of the two processes, i.e. seismogenesis and gas overloading
Non Abelian BF theories with sources and 2-D gravity
We study the interaction of non-Abelian topological theories defined on
two dimensional manifolds with point sources carrying non-Abelian charges. We
identify the most general solution for the field equations on simply and
multiply connected two-manifolds. Taking the particular choice of the so-called
extended Poincar\'e group as the gauge group we discuss how recent discussions
of two dimensional gravity models do fit in this formalism.Comment: 20 pages, Latex, To appear in Phys Rev D5
Scattering of Plane Waves in Self-Dual Yang-Mills Theory
We consider the classical self-dual Yang-Mills equation in 3+1-dimensional
Minkowski space. We have found an exact solution, which describes scattering of
plane waves. In order to write the solution in a compact form, it is
convenient to introduce a scattering operator . It acts in the direct
product of three linear spaces: 1) universal enveloping of Lie algebra,
2) -dimensional vector space and 3) space of functions defined on the unit
interval.Comment: 16 pages, LaTeX fil
Platelet isoprostane overproduction in diabetic patients treated with aspirin
Aspirin modestly influences cardiovascular events in patients with type 2 diabetes mellitus (T2DM), but the reason is unclear. The aim of the study was to determine whether in T2DM patients aspirin enhances platelet isoprostanes, which are eicosanoids with proaggregating properties derived from arachidonic acid oxidation by platelet NOX2, the catalytic subunit of reduced NAD phosphate oxidase. A cross-sectional study was performed comparing T2DM patients, treated (n = 50) or not treated (n = 50) with 100 mg/day aspirin, with 100 nondiabetic patients, matched for age, sex, atherosclerosis risk factors, and aspirin treatment. A short-term (7 days) treatment with 100 mg/day aspirin also was performed in 36 aspirin-free diabetic and nondiabetic patients. Higher platelet recruitment, platelet isoprostane, and NOX2 activation was found in diabetic versus nondiabetic patients and in aspirin-treated diabetic patients versus nontreated patients (P < 0.001). Platelet thromboxane (Tx) A(2) (P < 0.001) was inhibited in all aspirin-treated patients. In the interventional study, aspirin similarly inhibited platelet TxA(2) in diabetic and nondiabetic patients (P < 0.001). Platelet recruitment, isoprostane levels, and NOX2 activation showed a parallel increase in diabetic patients (P < 0.001) and no changes in nondiabetic patients. These findings suggest that in aspirin-treated diabetic patients, oxidative stress-mediated platelet isoprostane overproduction is associated with enhanced platelet recruitment, an effect that mitigates aspirin-mediated TxA(2) inhibition
EGFR CELL EXPRESSION IN BLADDER WASHINGS AS A RISK MARKER TOOL IN NON MUSCLE-INVASIVE BLADDER CANCER. PRELIMINARY EXPERIENCE
INTRODUCTION AND OBJECTIVES: Up to day, EGFR
expression has been determined mainly in tissue specimens of muscleinvasive
bladder cancer and its overexpression has been associated
with worse prognosis and shorter survival. Urothelial EGFR status after
NMIBC transurethral resection (TUR) could indicate the risk of recurrence
and progression. We investigated the feasibility of EGFR measurement
in bladder washings of patients undergoing intravesical
adjuvant therapy for NMIBC and its usefulness in identifying risk
subgroups.
METHODS: Our prospective study included patients after TUR
of NMIBC and healthy controls. A cellular pellet was obtained from
bladder washing, and RNA extraction performed by miRNeasy Mini Kit
(Qiagen). Good quality of RNA was checked. The cDNA obtained
from RNA was used to perform a gene expression analysis by a Real
Time PCR, according to the method of the comparative quantification
(DDCt) with an endogenous control (Cyclophilin). Every reaction was
set in triplicate as a guarantee of quality. Patients were grouped for EAU
risk class and maintained in follow-up. The EGFR expressions were
statistically analyzed according to EAU risk groups and to patients0
outcome. EGFR gene expression values were expressed in FOLDs of
change compared to healthy controls (EGFRŒ1).
RESULTS: Fifty-eight patients and 21 healthy age-matched
controls were entered. An adequate cellular pellet was obtained in 50
patients (86.2%) showing a median EGFR expression of 2.0 folds (IQR
0.6-4.3, pŒ0.0004). After TUR and adjuvant intravesical therapy, 22
(55%) out of 40 high-risk patients, showed EGFR decrease to 1.3 folds
(IQR 0.9-1.5), while 18 (45%) showed elevated EGFR, median 4.7 (IQR
4.1-11.6). At 25 months median follow-up (IQR 19.0-34.8), 20 (40%)
patients recurred and 6 (12%) progressed. Among patients with or
without EGFR gene increase, 9 (22.5%) and 5 (12.5%) recurred and 5
(12.5%) and 1 (2.5%) progressed, respectively.
CONCLUSIONS: In our experience EGFR expression measurement
was feasible in more than 85% of patients and resulted
related to EAU risk classes for recurrence and progression, showing
different behavior during intravesical therapy. It was possible to identify
a subgroup of high risk patients overexpressing EGFR in spite of
intravesical adjuvant therapy. EGFR evaluation in bladder washing
could represent a repeatable and useful tool to identify a subgroup of
patients at risk for progression unresponsive to intravesical adjuvant
therapy and candidate to early radical cystectom
Speech Prosody as a Bridge Between Psychopathology and Linguistics: The Case of the Schizophrenia Spectrum
Patients with schizophrenia spectrum disorders experience severe difficulties in interpersonal communication, as described by traditional psychopathology and current research on social cognition. From a linguistic perspective, pragmatic abilities are crucial for successful communication. Empirical studies have shown that these abilities are significantly impaired in this group of patients. Prosody, the tone of voice with which words and sentences are pronounced, is one of the most important carriers of pragmatic meaning and can serve a range of functions from linguistic to emotional ones. Most of the existing literature on prosody of patients with schizophrenia spectrum disorders focuses on the expression of emotion, generally showing significant impairments. By contrast, the use of non-emotional prosody in these patients is scarcely investigated. In this paper, we first present a linguistic model to classify prosodic functions. Second, we discuss existing studies on the use of non-emotional prosody in these patients, providing an overview of the state of the art. Third, we delineate possible future lines of research in this field, also taking into account some classical psychopathological assumptions, for both diagnostic and therapeutic purposes
A solution to the zero-hamiltonian problem in 2-D gravity
The zero-hamiltonian problem, present in reparametrization invariant systems,
is solved for the 2-D induced gravity model. Working with methods developed by
Henneaux et al. we find systematically the reduced phase-space physics,
generated by an {\it effective} hamiltonian obtained after complete gauge
fixing.Comment: 5 pages, revte
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