6,726 research outputs found
Seismic Q estimates in Umbria-Marche (central Italy): hints for the retrieval of a new attenuation law for seismic risk
In the Umbria Marche (Central Italy) region an important earthquake sequence occurred in 1997,
characterized by nine earthquakes with magnitudes in the range between 5 and 6, that caused
important damages and causalities. In the present paper we separately estimate intrinsic- and
scattering- Q
â1
parameters, using the classical MLTWA approach in the assumption of a half space
model. The results clearly show that the attenuation parameters Qi
â1
and Qs
â1
are frequency
dependent. This estimate is compared with other attenuation studies carried out in the same area, and
with all the other MLTWA estimates obtained till now in other tectonic environments in the Earth.
The bias introduced by the half space assumption is investigated through numerical solutions of the
Energy Transport equation in the more realistic assumption of a heterogeneous crust overlying a
transparent mantle, with a Moho located at a depth ranging between 35 and 45 km below the surface.
The bias introduced by the half space assumption is significant only at high frequency. We finally
show how the attenuation estimates, calculated with different techniques, lead to different PGA decay
with distance relationships, using the well known and well proven Booreâs method. This last result
indicates that care must be used in selecting the correct estimate of the attenuation parameters for
seismic risk purposes. We also discuss the reason why MLTWA may be chosen among all the other
available techniques, due to its intrinsic stability, to obtain the right attenuation parameters
Inclusive University didactics and technological devices: a case study
This paper provides a review of projects related to new technologies used to favour the teaching-learning processes and the inclusive practices in the University context for students with disabilities and with Specific Learning Disorders. Authors present a review of strategies, trajectories and perspectives activated in the national and international scene, aiming to guarantee a significant pedagogical framework of reference. Furthermore, the paper focuses on a meaningful path activated at the University of Macerata, the project Inclusion 3.0, a relevant example of new technologies in support of teaching- learning processes and inclusion practices among all students
The first Long Period earthquake detected in the background seismicity at Mt. Vesuvius
The typical earthquakes occurring at Mt. Vesuvius are Volcano-Tectonic. On July 20, 2003, an unusual earthquake with low and narrow frequency content was detected. The seismograms presented an emergent onset and a nearly monochromatic spectrum at all stations of the Osservatorio Vesuviano(Istituto Nazionale di Geofisica e Vulcanologia) seismic network. The event was located at about 4 km b.s.l. close to the crater axis and an equivalent duration magnitude of 0.6 was estimated. The nature of this event was investigated by comparing its features with those of two typical
Volcano-Tectonic earthquakes occurred inside the same source volume. We compared the spectral content calculating the spectrograms and the coda patterns using the Hilbert Transform. A Seismic Moment Tensor inversion was performed on the low frequency earthquake. The focal mechanisms for the two Volcano-Tectonic earthquakes were estimated with a classical technique and resulted compatible with the stress field acting on the volcano. Taking into account the clear differences with the typical Volcano-Tectonic events as well as the peculiarities retrieved from our analyses (monochromatic, low frequency spectral content, and sustained coda) and also some geochemical observations, we classify the unusual low frequency seismic event detected at Mt. Vesuvius as Long Period earthquake and propose that its origin could be linked to a pressure drop in the deep hydrothermal system
Measurement of the water vapour vertical profile and of the Earth's outgoing far infrared flux
International audienceOur understanding of global warming depends on the accuracy with which the atmospheric components that modulate the Earth's radiation budget are known. Many uncertainties still exist on the radiative effect of water in the different spectral regions, among which the far infrared where few observations have been made. An assessment is shown of the atmospheric outgoing flux obtained from a balloon-borne platform with wideband spectrally resolved nadir measurements at the top-of-atmosphere over the full spectral range, including the far infrared, from 100 to 1400 cm?1, made by a Fourier transform spectrometer with uncooled detectors. From these measurements, we retrieve 15 pieces of information about water vapour and temperature profiles, and surface temperature, with a precision of 5% for the mean water vapour profile and a major improvement of the upper troposphere-lower stratosphere knowledge. The retrieved atmospheric state makes it possible to calculate the emitted radiance as a function of the zenith angle and to determine the outgoing radiation flux, proving that spectrally resolved observations can be used to derive accurate information on the integrated flux. While the retrieved temperature is in good agreement with ECMWF analysis, the retrieved water vapour profile differs significantly, and, depending on time and location, the derived flux differs in the far infrared (0?600 cm?1) from that derived from ECMWF by 2?3.5 W/m2±0.4 W/m2. The observed discrepancy is larger than current estimates of radiative forcing due to CO2 increases since pre-industrial time. The error with which the flux is determined is caused mainly by calibration uncertainties while detector noise has a negligible effect, proving that uncooled detectors are adequate for top of the atmosphere radiometry
Differences in telomere length between sporadic and familial cutaneous melanoma
BACKGROUND:
Several pieces of evidence indicate that a complex relationship exists between constitutional telomere length (TL) and the risk of cutaneous melanoma. Although the general perception is that longer telomeres increase melanoma risk, some studies do not support this association. We hypothesise that discordant data are due to the characteristics of the studied populations.
OBJECTIVES:
To evaluate the association of telomere length with familial and sporadic melanoma.
METHODS:
TL was measured by multiplex quantitative PCR in leukocytes from 310 melanoma patients according to familial/sporadic and single/multiple cancers and 216 age-matched controls.
RESULTS:
Patients with sporadic melanoma were found to have shorter telomeres as compared to those with familial melanoma. In addition, shorter telomeres, while tending to reduce the risk of familial melanoma regardless of single or multiple tumors, nearly trebled the risk of single sporadic melanoma.
CONCLUSIONS:
This is the first time that TL has been correlated to opposite effects on melanoma risk according to the presence or absence of familial predisposition. Individual susceptibility to melanoma should be taken into account when assessing the role of TL as a risk factor. This article is protected by copyright. All rights reserved
New insights into Mt. Vesuvius hydrothermal system and its dynamic based on a critical review of seismic tomography and geochemical features
The seismic velocity and attenuation tomography images, calculated inverting
respectively P-wave travel times and amplitude spectra of local
VT quakes at Mt. Vesuvius have been reviewed and graphically represented
using a new software recently developed using Mathematica8TM.
The 3-D plots of the interpolated velocity and attenuation fields obtained
through this software evidence low-velocity volumes associated with high
attenuation anomalies in the depth range from about 1 km to 3 km below
the sea level. The heterogeneity in the distribution of the velocity and attenuation
values increases in the volume centred around the crater axis
and laterally extended about 4 km, where the geochemical interpretation
of the data from fumarole emissions reveals the presence of a hydrothermal
system with temperatures as high as 400-450°C roughly in the same
depth range (1.5 km to 4 km). The zone where the hydrothermal system
is space-confined possibly hosted the residual magma erupted by Mt. Vesuvius
during the recent eruptions, and is the site where most of the seismic
energy release has occurred since the last 1944 eruption
Comparison of four commercial screening assays for the detection of blakpc, blandm, blaimp, blavim, and blaoxa48 in rectal secretion collected by swabs
The spread of carbapenem-resistant Enterobacteriaceae (CRE) has been enabled by the lack of control measures directed at carriers of multidrug-resistant organisms in healthcare settings. Screening patients for asymptomatic colonization on the one hand, and implementation of contact precautions on the other hand, reduces patient-to-patient transmission. Screening plates represents a relatively low-cost method for isolating CRE from rectal swabs; however, molecular assays have become widely available. This study compared the performance of four commercial molecular platforms in detecting clinically significant carbapenemase genes versus routine screening for CRE. A total of 1015 non-duplicated rectal swabs were cultured on a chromogenic carbapenem-resistant selective medium. All growing Enterobacteriaceae strains were tested for carbapenemase-related genes. The same specimens were processed using the following molecular assays: Allplex\u2122 Entero-DR, Amplidiag\uae CarbaR + MCR, AusDiagnostics MT CRE EU, and EasyScreen\u2122 ESBL/CPO. The prevalence of Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacteriaceae detected by swab culture was 2.2%, while organisms producing oxacillinase (OXA)-48 and metallo-\u3b2-lactamases were infrequent. The cost of CRE-related infection control precautions, which must be kept in place while waiting for screening results, are significant, so the molecular tests could become cost-competitive, especially when the turnaround time is decreased dramatically. Molecular assays represent a powerful diagnostic tool as they allow the rapid detection of the most clinically relevant carbapenemases
Prognostic role of amenorrhea induced by adjuvant chemotherapy in premenopausal patients with early breast cancer.
The prognostic role of drug-induced amenorrhea (DIA) was restrospectively evaluated in 221 out of 254 consecutive premenopausal patients treated with adjuvant CMF or a CMF-containing regimen; 33 patients were eliminated because of lack of menstrual data. All patients had metastatic axillary nodes; drug regimens were: CMF x 9 courses +/- Tamoxifen (TM) and CMF x 6 courses; median age was 43 (range 26-54). Premenopausal status was defined as last normal menses within the 6 weeks preceding initiation of chemotherapy: DIA as cessation of menses for at least 3 months not later than 3 months from the end of chemotherapy. DIA occurred in 166,221 (75.1%) patients and was strictly related to the age of the patients; also, the older the patients the shorter the time required to develop DIA. At median follow up of 69 months, Mantel-Byar analysis showed a longer disease free survival (DFS) for patients who developed DIA as compared with non amenorrheic women (P less than 0.001). DIA prognostic value was independent of age, number of involved nodes, tumour size and number of CMF cycles, as assessed by the Cox model (RH 0.43, 95% C.I. 0.24-0.77), in which DIA was entered as a time dependent covariate
Immune senescence and immune activation in elderly colorectal cancer patients
In our previous study, we found that low thymic output and short telomere length were associated with a higher risk of tumor in elderly cancer patients. Here, we aimed to examine in depth the impact of immunological and biological senescence and immune activation on disease outcome in elderly patients with colorectal cancer (CRC).Peripheral blood samples from 81 CRC patients were studied for immune activation, immune senescence and recent thymic emigrant (RTE) CD4 and CD8 cells by flow cytometry. T-cell receptor rearrangement excision circle (TREC) levels and telomere lengths were measured by real-time PCR. Plasma levels of microbial translocation markers, LPS and sCD14, were quantified by ELISA. While TREC levels and telomere length were not prognostic of disease outcome, high percentages of immune senescent and immune activated CD8 cells were associated with a higher risk of a negative event (relapse, progression, or death) in all studied patients and disease relapse in I-Ill staged patients. Levels of sCD14 and LPS were higher in patients who will experience a negative event than in patients who will not. In conclusion, in elderly CRC patients higher immunological senescence and immune activation negatively impact the disease outcome; how these characteristics influence the antineoplastic treatments remains to be investigated
Characterization of gaze in handwriting of High and Low Frequency Word of Schoolchildren with Dyslexia
Writing is extremely important for our academic and professional life and can affect our performance in productive educational activities, favouring us or not. Schoolchildren with dyslexia bring difficulties and reduced school performance due to their condition of deprivation in written production. This is because schoolchildren with dyslexia have difficulty acquiring spelling knowledge and show poor phonological skills. This study aimed to characterize the performance of schoolchildren with dyslexia in âgazeâ for the handwriting of High and Low-frequency words. A total of 24 schoolchildren participated in the study. They were between 8 to 11 years and 11 months of age, of both sexes, and they were attending the 3rd to the 5th year of Elementary School in the city of MarĂlia-SP. The schoolchildren were divided into groups: GI, composed of 12schoolchildren with an interdisciplinary diagnosis of developmental dyslexia, and GII, composed of 12 schoolchildren with good academic performance, paired with GI according to the school grade level. These schoolchildren were submitted to computerized handwriting evaluation using a Brazilian adaptation of the Software Ductus. All schoolchildren were submitted to a copy of words already selected according to Brazilian Portuguese criteria of frequency and codification rule. A measure of âgazeâ was used, that is, when the schoolchildren stopped their handwriting to search/look up at the screen to confirm the information about the words. The results indicated a significant difference between GI and GII, with GI schoolchildren performing more gaze when compared with GII, i.e., taking longer motor breaks to perform the gaze. Therefore, there was a rupture in the central processing with the peripheral when the child performed the gauze more times since he had to confirm the characteristics of this word during the writing process (difficulty in accessing the orthographic lexicon) and with that, there was a break in the movement of handwriting (since there was not enough information in the central plane to complete that motor memory and finish the word). It was concluded that there were gaps between the central (orthographic) and peripheral (motor pauses processes, suggesting deficits in the formation of motor programs for GI and the lack of automation of motor processes
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