76 research outputs found
Podocyte-Specific Overexpression of Wild Type or Mutant Trpc6 in Mice Is Sufficient to Cause Glomerular Disease
Mutations in the TRPC6 calcium channel (Transient receptor potential channel 6) gene have been associated with familiar forms of Focal and Segmental Glomerulosclerosis (FSGS) affecting children and adults. In addition, acquired glomerular diseases are associated with increased expression levels of TRPC6. However, the exact role of TRPC6 in the pathogenesis of FSGS remains to be elucidated. In this work we describe the generation and phenotypic characterization of three different transgenic mouse lines with podocyte-specific overexpression of the wild type or any of two mutant forms of Trpc6 (P111Q and E896K) previously related to FSGS. Consistent with the human phenotype a non-nephrotic range of albuminuria was detectable in almost all transgenic lines. The histological analysis demonstrated that the transgenic mice developed a kidney disease similar to human FSGS. Differences of 2–3 folds in the presence of glomerular lesions were found between the non transgenic and transgenic mice expressing Trpc6 in its wild type or mutant forms specifically in podocytes. Electron microscopy of glomerulus from transgenic mice showed extensive podocyte foot process effacement. We conclude that overexpression of Trpc6 (wild type or mutated) in podocytes is sufficient to cause a kidney disease consistent with FSGS. Our results contribute to reinforce the central role of podocytes in the etiology of FSGS. These mice constitute an important new model in which to study future therapies and outcomes of this complex disease
Discutindo a educação ambiental no cotidiano escolar: desenvolvimento de projetos na escola formação inicial e continuada de professores
A presente pesquisa buscou discutir como a Educação Ambiental (EA) vem sendo trabalhada, no Ensino Fundamental e como os docentes desta escola compreendem e vem inserindo a EA no cotidiano escolar., em uma escola estadual do municĂpio de Tangará da Serra/MT, Brasil. Para tanto, realizou-se entrevistas com os professores que fazem parte de um projeto interdisciplinar de EA na escola pesquisada. Verificou-se que o projeto da escola nĂŁo vem conseguindo alcançar os objetivos propostos por: desconhecimento do mesmo, pelos professores; formação deficiente dos professores, nĂŁo entendimento da EA como processo de ensino-aprendizagem, falta de recursos didáticos, planejamento inadequado das atividades. A partir dessa constatação, procurou-se debater a impossibilidade de tratar do tema fora do trabalho interdisciplinar, bem como, e principalmente, a importância de um estudo mais aprofundado de EA, vinculando teoria e prática, tanto na formação docente, como em projetos escolares, a fim de fugir do tradicional vĂnculo “EA e ecologia, lixo e horta”.Facultad de Humanidades y Ciencias de la EducaciĂł
Imaging of crustal scatterers using multiple seismic arrays
Array seismology is an useful tool to perform a detailed investigation of the Earth’s interior. Seismic arrays by using the coherence properties of the wavefield are able to extract directivity information and to increase the ratio of the coherent signal amplitude relative to the amplitude of incoherent noise. The Double Beam Method (DBM), developed by Krüger et al. (1993, 1996), is one of the possible applications to perform a refined seismic investigation of the crust and mantle by using seismic arrays. The DBM is based on a combination of source and receiver arrays leading to a further improvement of the signal-to-noise ratio by reducing the error in the location of coherent phases. Previous DBM works have been performed for mantle and core/mantle resolution (Krüger et al., 1993; Scherbaum et al., 1997; Krüger et al., 2001). An implementation of the DBM has been presented at 2D large-scale (Italian data-set for Mw=9.3, Sumatra earthquake) and at 3D crustal-scale as proposed by Rietbrock & Scherbaum (1999), by applying the revised version of Source Scanning Algorithm (SSA; Kao & Shan, 2004). In the 2D application, the rupture front propagation in time has been computed. In 3D application, the study area (20x20x33 km3), the data-set and the source-receiver configurations are related to the KTB-1994 seismic experiment (Jost et al., 1998). We used 60 short-period seismic stations (200-Hz sampling rate, 1-Hz sensors) arranged in 9 small arrays deployed in 2 concentric rings about 1 km (A-arrays) and 5 km (B-array) radius. The coherence values of the scattering points have been computed in the crustal volume, for a finite time-window along all array stations given the hypothesized origin time and source location. The resulting images can be seen as a (relative) joint log-likelihood of any point in the subsurface that have contributed to the full set of observed seismograms
How likely does shear wave splitting and moment tensor parameters interact for the “2016 -2018 central Italy seismic sequence” ?
The “2016-2018 Central-Italy seismic sequence” is
characterized by a Mw 6.0 mainshock that
occured close to the towns of Accumoli and
Amatrice at 1:36 a.m. (UTC) of August 24th 2016
and it is still ongoing. In 20 months activity, 63905
recorded earthquakes are spatially elongated NW-
SE, the aftershocks are mainly concentrated
between 2 and 25 km of depth with minimum and
maximum magnitude ranging from Mw 0.1 to 6.5,
respectively. This study area is characterized by a
complex geological and structural setting derived
by multi-phased contractional and extensional
deformation began in the Early Tertiary. In detail,
the epicentral area is located in the central sector
of Apennine chain characterized by several NW-SE
oriented Quaternary fault systems and
compressional fronts. Nowadays stress indicators
(such as borehole breakouts, anisotropic
parameters, earthquake focal mechanisms and
active faults) point out that the axial part of the
Apennine belt is characterized by a general
extension about NE-SW oriented. Slip data from
Amatrice fault structures show that roughly N–S
trending leftlateral strike–slip and
transtensional/normal faults are all kinematically
consistent with the existence of a Late
Quaternary. The remote stress field is
characterized by a NE–SW-oriented minimum
horizontal stress (Shmin, sigma3 or maximum
extension) and by a NW–SE trending maximum
horizontal stress (SHmax, sigma1 or maximum
compression). In this preliminary study we define
the possible correlations between shear wave
splitting and moment tensor parameters during
the “2016-2018 Central-Italy seismic sequence”.
Shear Wave Splitting phenomenon is described by
2 parameters: fast polarization direction and delay
time. Generally, fast component strikes as the
orientation of the anisotropic symmetry axes, and
delay time measures the anisotropic strength. In
this geo-structural context, for sedimentary rocks,
according to the Extensive Dilatancy Anisotropy
(EDA) model and its evolution in Anisotropic Poro
Elasticity (APE) the local variations of the
anisotropic parameters are both time and space
dependent. As a consequence the fast direction
will be parallel to the SHmax direction and the
delay time will measure the intensity and/or
thickness of the fracture field. Moreover, SHmax
corresponds to sigma1 (thrust and strike-slip
faulting regime) or sigma2 (normal faulting
regime) and can be related to P, T and B axes
orientations of seismic moment tensors. In this
assumption, we analyze the spatial variations of
local stress-field in term of SHmax which is strictly
related to sigma, and fast polarization direction.
After computing the parameters above described,
we compare them with the stress field and
geologic structures of the crust to explain the
tectonic processes.PublishedMalta2T. Deformazione crostale attiva3T. Sorgente sismic
Preliminary earthquake focal mechanism forecasts for the Amatrice sequence (central Italy)
We place the Amatrice (central Italy) seismic sequence and the related epicentral area in a contest of Probabilistic Seismic Hazard Analysis (PSHA). We apply a procedure to compute the probability to observe in the future a normal, reverse or strike-slip event and the average distribution of the P, T and N axes. This is a fundamental step to reduce the uncertainty connected to the Ground Motion Prediction Equation models, part of PSHA. For this purpose we use a significant focal mechanism catalogue and the latest present-day stress field data release for Italy to produce forecasted information that we compare with the equivalent data observed during the sequence
Non-Double-Couple Component Analysis of Induced Microearthquakes in the Val d’Agri Basin (Italy)
In recent years it has become accepted that earthquake source can attain significant Non-Double-Couple (NDC) components. Among the driving factors of deviation from normal double-couple (DC) mechanisms there is the opening/closing of fracture networks and the activation of pre-existing faults by pore fluid pressure perturbations. This observation makes the thorough analysis of source mechanism of key importance for the understanding of withdrawal/injection induced seismicity from geothermal and hydrocarbon reservoirs, as well as of water reservoir induced seismicity. In addition to the DC component, seismic moment tensor can be decomposed into isotropic (ISO) and compensated linear vector dipole (CLVD) components. In this study we performed a careful analysis of the seismic moment tensor of induced microseismicity recorded in the Val d'Agri (Southern Apennines, Italy) focusing our attention on the NDC component. The Val d'Agri is a Quaternary extensional basin that hosts the largest onshore European oil field and a water reservoir (Pertusillo Lake impoundment) characterized by severe seasonal level oscillations. Our input data-set includes swarm-type induced micro-seismicity recorded between 2005-2006 by a high-performance network and accurately localized by a reservoir-scale local earthquake tomography. We analyze two different seismicity clusters: (i) a swarm of 69 earthquakes with 0.3 ML 1.8 induced by a wastewater disposal well of the oilfield during the initial daily injection tests (10 days); (ii) 526 earthquakes with -0.2 ML 2.7 induced by seasonal volume changes of the artificial lake. We perform the seismic moment tensor inversion by using HybridMT code. After a very accurate signal-to-noise selection and hand-made picking of P-pulses, we obtain %DC, %ISO, %CLVD for each event. DC and NDC components are analyzed and compared with the spatio-temporal distribution of seismicity, the local stress field, the injection parameters and the water level in the impoundment. We find significant NDC components and abrupt temporal variations in the DC and ISO components that appear linked to the extremely variable parameters of the injection tests into the disposal well.PublishedNew Orleans, LA2T. Sorgente Sismic
Analysis of the source parameters behaviour during the Val D'Agri test-injection (Italy)
Recent advances in understanding induced
earthquake mechanics are due to the new and
high-quality observations from seismic signals,
natural faults and laboratory experiments. The
synergy of different approaches allows the
acquisition of useful observations to understand
the earthquake source process. In this study we
investigate the source parameters behaviour of
induced earthquakes recorded during daily
injection tests in a wastewater disposal well in Val
D’Agri (VDA, Italy). We choose this area because
of its complexity and particularity. VDA is a
Quaternary extensional basin located in the
Southern Apennines characterized by a complex
tectonic evolution, high seismic hazard and
significant hydrocarbon exploitation. The basin
hosts the largest onshore oilfield in Europe that
produces oil and associated gas from low-
porosity, fractured Cretaceous limestone.
Wastewater associated to hydrocarbon
production is reinjected into the Costa Molina 2
high-rate well (CM2) into an unproductive
marginal portion of the carbonate reservoir at
2890-3096 m depth (b.s.l.). Initial injection tests
were performed from 2 to 12 June 2006 with
variable duration (from 4 to 32 hr) and hourly
injection rate of 38 m3/hr. During the tests a
maximum well-head pressure of 101 bar was
measured. These tests induced a swarm
microseismicity (69 events, ML comprised by 0.3
and 1.8) recorded by a high-performance local
network run by INGV (Mc 0.4, 23 stations) that
constitutes our testing data-set. We investigate
the full moment tensors decomposing them in
Double-Couple (DC), Isotropic (ISO) and
Compensated Linear Vector Dipole (CLVD)
components by using HybridMT technique. We
obtain significant contribution of %ISO and %CLVD
components that tend to increase with time. Also,
we compute the moment magnitudes (that we
compare with ML) and the static stress drops (by
spectral analysis). Finally, we discuss each
analysed source parameter as a function of the
injection pressure curve in the geological/tectonic
contest.PublishedMalta3T. Sorgente sismic
Earthquake focal mechanism forecasting in Italy for PSHA purposes
This article has been accepted for publication in Geophysical Journal Internationa ©: 2018 Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.n this paper, we put forward a procedure that aims to forecast focal mechanism of future earthquakes. One of the primary uses of such forecasts is in probabilistic seismic hazard analysis (PSHA); in fact, aiming at reducing the epistemic uncertainty, most of the newer ground motion prediction equations consider, besides the seismicity rates, the forecast of the focal mechanism of the next large earthquakes as input data. The data set used to this purpose is relative to focal mechanisms taken from the latest stress map release for Italy containing 392 well-constrained solutions of events, from 1908 to 2015, with Mw ≥ 4 and depths from 0 down to 40 km. The data set considers polarity focal mechanism solutions until to 1975 (23 events), whereas for 1976-2015, it takes into account only the Centroid Moment Tensor (CMT)-like earthquake focal solutions for data homogeneity. The forecasting model is rooted in the Total Weighted Moment Tensor concept that weighs information of past focal mechanisms evenly distributed in space, according to their distance from the spatial cells and magnitude. Specifically, for each cell of a regular 0.1° × 0.1° spatial grid, the model estimates the probability to observe a normal, reverse, or strike-slip fault plane solution for the next large earthquakes, the expected moment tensor and the related maximum horizontal stress orientation. These results will be available for the new PSHA model for Italy under development. Finally, to evaluate the reliability of the forecasts, we test them with an independent data set that consists of some of the strongest earthquakes with Mw ≥ 3.9 occurred during 2016 in different Italian tectonic provinces. © The Authors 2017. Published by Oxford University Press on behalf of The Royal Astronomical Society.Published491–5083T. Sorgente sismica6T. Studi di pericolosità sismica e da maremotoJCR Journa
Historical faulting as the possible cause of earthquake damages in the ancient Roman port city of Ostia
This paper presents an original multidisciplinary (geological-structural-geomorphological and seismological) study aimed at investigating the origin of diffused seismic damages affecting several ancient buildings in the Roman port city of Ostia. We also evaluate the possibility to relate these damages to a previously hypothesized ENE-WSW trending fault, bordering the morphological height upon which the Ostia town was founded. Aimed at this scope, we performed seismic noise measures (by using 14 seismic stations) that show no significantly different response and lack of significant ground motion differential amplifications. The coexistence of (i) no local geological heterogeneities and (ii) low amplification of spectral ratios in the recorded seismic signals seems to exclude that the observed seismic damage may be the consequence of significant site effects. When also the large distance from the strongest Apennine’s seismogenic source areas is considered, the possibility that the observed damage may be the consequence of local events should be considered. We discuss the potentiality of the ENE-WSW trending fault as the source of the observed seismic damages, highlighting the supporting evidence as well as the uncertainties of such interpretation.Published833–8515T. Sismologia, geofisica e geologia per l'ingegneria sismicaJCR Journa
Identification of podocin (NPHS2) gene mutations in African Americans with nondiabetic end-stage renal disease
Identification of podocin (NPHS2) gene mutations in African Americans with nondiabetic end-stage renal disease.BackgroundPodocin, encoded byNPHS2 and mapped to 1q25.2, is an integral membrane protein exclusively expressed in glomerular podocytes. Mutations in theNPHS2 gene cause autosomal-recessive nephrotic syndrome and have been associated with proteinuria in several populations. Evidence for linkage of end-stage renal disease (ESRD) to chromosome 1q25-31 in the region ofNPHS2 has been identified in a genome-wide scan in African American (AA) siblings.MethodsTo investigate the potential role of this gene in ESRD, we sequenced all coding regions and approximately 2kb of upstream promoter sequence ofNPHS2 in 96 unrelated AA nondiabetic ESRD cases and 96 healthy population-based AA controls, and assessed several single nucleotide polymorphisms (SNPs) for association in a larger case-control sample.ResultsFifty-five variants were identified with minor allele frequencies ranging from <1% to 44%. Twenty-three polymorphisms were located in the promoter region, 11 were exonic, 13 were intronic, and 8 were in the 5′ and 3′- untranslated regions. Two novel nonsynonymous coding SNPs were identified (A44E and A61V). An insertion polymorphism in intron 3, IVS3+9insA, was detected in 6 ESRD patients and in no controls. This variant, and 4 other common SNPs, were evaluated in a larger sample of 288 AA ESRD cases and 278 AA controls. The overall minor allele frequencies for the insertion allele were 0.018 in cases and 0.002 in controls. Significant evidence of association of IVS3+9insA was observed (P = 0.012), and the haplotype containing the insertion allele in cases was also associated.ConclusionThese results suggest that uncommon variants of theNPHS2 gene may play a role in the development of nondiabetic ESRD in AAs
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