58 research outputs found

    Sedimentology and composition of sands injected during the seismic crisis of May 2012 (Emilia, Italy): clues for source layer identification and liquefaction regime

    Get PDF
    InMay 2012widespread sand blows formed along buried channels in the eastern sector of the Po Plain (Northern Italy) as a consequence of a series of seismic eventswith main shocks ofMw6.1 and 5.9. At San Carlo (Ferrara) a trench dug a few week after the earthquakes exposed sand dikes cutting through an old Reno River channel– levee system that was diverted in the 18th century and was deposited starting from the 14th century (unit A). This sequence overlies a Holocene muddy floodplain deposits and contains scattered sandy channel deposits (unit B) and a Pleistocene channel sand unit (unit C). Sands with inverse and normal grading, concave layering and vertical lamination coexisting along the dikes suggest multiple rhythmic opening and closing of the fractures that were injected and filled by a slurry of sand during the compression pulses, and emptied during the extension phase. The pulse mechanism may have lasted for several minutes and formed well stratified sand volcanoes structures that formed at the top of the fractures. Sands fromdikes and fromthe various units showwell defined compositional fields from lithoarenitic to quartz-feldspar-rich compositions. Sands from the old Reno levee and channel fill (unit A) have abundant lithic fragments derived fromthe erosion of Apennine sedimentary carbonate and terrigenous successions. Composition of the sand filling the dikes showclear affinities with sand layers of the old Reno River channel (Unit A) and clearly differ from any sand from deeper Holocene and Pleistocene layers (Unit B and C),which are richer in quartz and feldspar and poorer in sedimentary lithic fragments. Sorting related to sediment flux variations did not apparently affect the sand composition across the sedimentary structures. Textural and compositional data indicate that the liquefaction processes originated from a relatively shallow source consisting of channel sands located within Unit A at 6.8.to 7.5 m depth

    Liquefaction source layer for sand blows induced by the 2016 megathrust earthquake (Mw 7.8) in Ecuador (Boca de Briceño)

    Get PDF
    Numerous sand boils were generated in the alluvial plain at the mouth of the Rio Brice˜no valley (Ecuador) during the Mw 7.8 earthquake of April 2016. The area is characterized by a series of raised marine terraces formed as a consequence of the rapid tectonic coastal uplift during the Quaternary. Boreholes and geotechnical investigations were carried during post-earthquake surveys and for the purpose of mitigating the liquefaction effects. Five lithological units were identified at a site of embankment, which represented continental-marine and transitional sedimentation since the Last Glacial Maximum. A comprehensive study of texture and petrographic composition of sand boils has been performed and compared with sandy silts and silty sands of the buried sedimentary sequence in order to identify the source levels for liquefaction. The petrographic components, in particular the low content of bioclasts and carbonate fragments of the sand boils, allow to pinpoint a source layer made up of fine-grained silty sands located between 2 and 4.5 m depth (Unit 2) whereas the deeper marine sands, richer in bioclasts, were not involved. The results support the idea that earthquake-induced liquefaction phenomena are not restricted to clean sands and well-sorted deposits, but may affect sand layers with significant amount of nonplastic silt

    Clinical Study Respiratory Muscle Training in Patients Recovering Recent Open Cardiothoracic Surgery: A Randomized-Controlled Trial

    Get PDF
    Objectives. To evaluate the clinical efficacy and feasibility of an expiratory muscle training (EMT) device (Respilift) applied to patients recovering from recent open cardiothoracic surgery (CTS). Design. Prospective, double-blind, 14-day randomisedcontrolled trial. Participants and Setting. A total of 60 inpatients recovering from recent CTS and early admitted to a pulmonary rehabilitation program. Interventions. Chest physiotherapy plus EMT with a resistive load of 30 cm H 2 O for active group and chest physiotherapy plus EMT with a sham load for control group. Measures. Changes in maximal expiratory pressure (MEP) were considered as primary outcome, while maximal inspiratory pressures (MIP), dynamic and static lung volumes, oxygenation, perceived symptoms of dyspnoea, thoracic pain, and well being (evaluated by visual analogic scale-VAS) and general health status were considered secondary outcomes. Results. All outcomes recorded showed significant improvements in both groups; however, the change of MEP (+34.2 mmHg, < 0.001 and +26.1%, < 0.001 for absolute and % of predicted, resp.) was significantly higher in active group. Also VAS dyspnoea improved faster and more significantly ( < 0.05) at day 12, and 14 in active group when compared with control. The drop-out rate was 6%, without differences between groups. Conclusions. In patients recovering from recent CTS, specific EMT by Respilift is feasible and effective. This trial is registered with ClinicalTrials.gov NCT01510275

    Effects of initial-state dynamics on collective flow within a coupled transport and viscous hydrodynamic approach

    Full text link
    We evaluate the effects of preequilibrium dynamics on observables in ultrarelativistic heavy-ion collisions. We simulate the initial nonequilibrium phase within A MultiPhase Transport (AMPT) model, while the subsequent near-equilibrium evolution is modeled using (2+1)-dimensional relativistic viscous hydrodynamics. We match the two stages of evolution carefully by calculating the full energy-momentum tensor from AMPT and using it as input for the hydrodynamic evolution. We find that when the preequilibrium evolution is taken into account, final-state observables are insensitive to the switching time from AMPT to hydrodynamics. Unlike some earlier treatments of preequilibrium dynamics, we do not find the initial shear viscous tensor to be large. With a shear viscosity to entropy density ratio of 0.120.12, our model describes quantitatively a large set of experimental data on Pb+Pb collisions at the Large Hadron Collider(LHC) over a wide range of centrality: differential anisotropic flow vn(pT) (n=26)v_n(p_T) ~(n=2-6), event-plane correlations, correlation between v2v_2 and v3v_3, and cumulant ratio v2{4}/v2{2}v_2\{4\}/v_2\{2\}.Comment: 10 pages, v2: minor revisio

    Multidisciplinary geological excursion in the open-air laboratory of the Island of Malta. 11-18 November 2010. Field-Trip Guide.

    Get PDF
    Si tratta della guida all'escursione geologica multidisciplinare tenutasi a Malta dall'11 al 18 novembre 2010, nell'ambito del progetto di internazionalizzazione dell'Università di Modena e Reggio Emilia dal titolo "Multidisciplinary research in the open-air laboratory of the island of Malta: an internazional network for landslide hazard assessment in coastal areas" (2008-2010) finanziato dalla Fondazione Cassa di Risparmio di Modena e Reggio Emilia, per i Corsi di Laurea Triennale in Scienze Geologiche e Magistrale in Scienze e Tecnologie Geologiche

    Toward a Coordinated Understanding of Hydro-Biogeochemical Root Functions in Tropical Forests for Application in Vegetation Models

    Get PDF
    Tropical forest root characteristics and resource acquisition strategies are underrepresented in vegetation and global models, hampering the prediction of forest–climate feedbacks for these carbon-rich ecosystems. Lowland tropical forests often have globally unique combinations of high taxonomic and functional biodiversity, rainfall seasonality, and strongly weathered infertile soils, giving rise to distinct patterns in root traits and functions compared with higher latitude ecosystems. We provide a roadmap for integrating recent advances in our understanding of tropical forest belowground function into vegetation models, focusing on water and nutrient acquisition. We offer comparisons of recent advances in empirical and model understanding of root characteristics that represent important functional processes in tropical forests. We focus on: (1) fine-root strategies for soil resource exploration, (2) coupling and trade-offs in fine-root water vs nutrient acquisition, and (3) aboveground–belowground linkages in plant resource acquisition and use. We suggest avenues for representing these extremely diverse plant communities in computationally manageable and ecologically meaningful groups in models for linked aboveground–belowground hydro-nutrient functions. Tropical forests are undergoing warming, shifting rainfall regimes, and exacerbation of soil nutrient scarcity caused by elevated atmospheric CO2. The accurate model representation of tropical forest functions is crucial for understanding the interactions of this biome with the climate

    Guidelines for the use of flow cytometry and cell sorting in immunological studies (third edition)

    Get PDF
    The third edition of Flow Cytometry Guidelines provides the key aspects to consider when performing flow cytometry experiments and includes comprehensive sections describing phenotypes and functional assays of all major human and murine immune cell subsets. Notably, the Guidelines contain helpful tables highlighting phenotypes and key differences between human and murine cells. Another useful feature of this edition is the flow cytometry analysis of clinical samples with examples of flow cytometry applications in the context of autoimmune diseases, cancers as well as acute and chronic infectious diseases. Furthermore, there are sections detailing tips, tricks and pitfalls to avoid. All sections are written and peer‐reviewed by leading flow cytometry experts and immunologists, making this edition an essential and state‐of‐the‐art handbook for basic and clinical researchers.DFG, 389687267, Kompartimentalisierung, Aufrechterhaltung und Reaktivierung humaner Gedächtnis-T-Lymphozyten aus Knochenmark und peripherem BlutDFG, 80750187, SFB 841: Leberentzündungen: Infektion, Immunregulation und KonsequenzenEC/H2020/800924/EU/International Cancer Research Fellowships - 2/iCARE-2DFG, 252623821, Die Rolle von follikulären T-Helferzellen in T-Helferzell-Differenzierung, Funktion und PlastizitätDFG, 390873048, EXC 2151: ImmunoSensation2 - the immune sensory syste

    Sand composition as a tool for liquefaction phenomena assessment

    No full text
    The petrographic composition of sands is a useful tool for the assessment of the complex phenomena related to co‐seismic liquefaction, such as sand blows, dykes, sand volcanoes and may also help in identifying ancient earthquake effects. Fluvial sand composition studies have a particular significance in the late Pleistocene–Holocene Po Plain, where distinct compositional fields characterize modern sands from different streams, as well as older sediments1 . Several key petrographic components provide diagnostic features to distinguish sand bodies buried beneath the floodplain. The composition of sands ejected during the 2012 Mw 6.1 Emilia earthquake from several sites in the Emilia plain (Modena and Ferrara provinces)2 has been compared with buried sands from cores and trenches at different depths (down to 50 m) in order to identify the source layers which originated the liquefaction phenomena. The sands from the cores show a clear trend from lithoarenitic to quartz‐feldspar‐rich compositions. The sands at shallow depth (down to 7 m) are the most lithoarenitic, with sedimentary fine‐grained rock fragments (limestone, shale and siltstone) as the dominant lithic type. Lithic fragments derive mostly from the erosion of sedimentary terrigenous and carbonate successions of Apenninic affinity referable to different fluvial systems (Secchia and Reno rivers). These shallow sands are well distinguishable from the deeper sands (at depth > 7 m), which show compositions slightly enriched in quartz and feldspars and impoverished in lithic fragments suggesting affinity with the Po river sands or older sands deposited during the last Glacial Maximum.   In all examined sites the composition of the ejected sands largely overlap that of the shallow late Holocene Apenninic sands, indicating that liquefaction processes affected mainly sand layers at depth of 6‐7.5 m. The study shows that composition of sands is crucial for a better understanding of earthquake‐ induced liquefaction mechanisms, in particular to identify the source layer of the sand blows and, more generally, for the recognition of critical layers, which may be prone to hazardous sand liquefaction phenomena
    corecore