A customized resistivity system for monitoring saturation and seepage in earthen levees: Installation and validation

This work is based on the assumption that a resistivity meter can effectively monitor water saturation in earth levees and can be used as a warning system when saturation exceeds the expected seasonal maxima. We performed time-lapse ERT measurements to assess the capability of this method to detect areas where seepage is critical. These measurements were also very useful to design a prototype monitoring system with remarkable savings by customizing the specifications according to field observations. The prototype consists of a remotely controlled low-power resistivity meter with a spread of 48 stainless steel 20 Ã 20 cm plate electrodes buried at half-meter depth. We deployed the newly-designed permanent monitoring system on a critical levee segment. A weather station and an ultrasonic water level sensor were also installed in order to analyse the correlation of resistivity with temperature, rainfalls and water level seasonal variations. The preliminary analysis of the monitoring data shows that the resistivity maps follow a very reasonable trend related with the saturation/drying cycle of the levee caused by the seasonal variations of the water level in the irrigation channel. Sharp water level changes cause delayed and smooth resistivity variations. Rainfalls and, to a lesser extent, temperature seem to have an influence on the collected data but effects are apparently negligible beyond 1 m depth. The system is currently operating and results are continuously monitored

geoelectrical characterization and monitoring of slopes on a rainfall triggered landslide simulator

Abstract In this paper, we present the results of time-lapse electrical resistivity tomography (ERT) monitoring of rainfall-triggered shallow landslides reproduced on a laboratory-scale physical model. The main objective of our experiments was to monitor rainwater infiltration through landslide body in order to improve our understanding of the precursors of failure. Time-domain reflectometry (TDR) data were also acquired to obtain the volumetric water content. Knowing the porosity, water saturation was calculated from the volumetric water content and we could calibrate Archie's equation to calculate water saturation maps from inverted resistivity values. Time-lapse ERT images proved to be effective in monitoring the hydrogeological conditions of the slope as well as in detecting the development of fracture zones before collapse. We performed eight laboratory tests and the results show that the landslide body becomes unstable at zones where the water saturation exceeds 45%. It was also observed that instability could occur at the boundaries between areas with different water saturations. Our study shows that time-lapse ERT technique can be employed to monitor the hydrogeological conditions of landslide bodies and the monitoring strategy could be extended to field-scale applications in areas prone to the development of shallow landslides

Sperimentazione di un sistema di monitoraggio geoelettrico permanente per la valutazione della stabilit\ue0 arginale

Gli argini sono l\u2019ultima difesa per salvaguardare le vite umane e i beni materiali dalla potenza distruttrice delle inondazioni. Sfortunatamente ad oggi in Italia non \ue8 prevista per legge una procedura sistematica e oggettiva di valutazione della stabilit\ue0 degli argini. I consorzi di Bonifica, enti preposti alla manutenzione dei rilevati arginali, eseguono infatti ispezioni visuali delle strutture, operazioni soggettive che dipendono fortemente dall\u2019operatore che realizza il sopralluogo. Negli ultimi decenni le metodologie geofisiche sono state utilizzate di frequente per valutare lo stato di salute dei rilevati in terra (Kim et al., 2007; Cardarelli et al., 2014) e in particolar modo la geoelettrica \ue8 stata utilizzata per il riconoscimento di zone di filtrazione preferenziale e per valutare la saturazione differenziale all\u2019interno delle strutture (Takakura et al., 2013; Perri et al., 2014; Loperte et al., 2016). Solo in pochi casi, per\uf2, sono stati implementati sistemi di monitoraggio permanenti (Hilbich et al., 2011; Supper et al., 2011). L\u2019obiettivo di questo lavoro \ue8 la valutazione della stabilit\ue0 dei rilevati arginali in terra in tempo reale, in una maniera indiretta, economica e efficace, grazie all\u2019implementazione di un monitoraggio geoelettrico per il riconoscimento di vie preferenziali di filtrazione e zone a contenuto d\u2019acqua non omogeneo

Sperimentazione alla scala di laboratorio per il monitoraggio di frane indotte da precipitazioni con misure geoelettriche time-lapse

Secondo l’Inventario dei Fenomeni Franosi d’Italia (IFFI), al 2016 le frane censite in Italia sono 614.799, interessano un’area pari al 7.5% del territorio nazionale e il 70.5% dei Comuni italiani. Le frane indotte da precipitazioni, inoltre, per la loro evoluzione veloce, sono una grave minaccia per l’incolumità della popolazione, dei beni e delle infrastrutture del territorio che, in assenza di un sistema di allerta adeguato non possono essere salvaguardati. Lo studio e il monitoraggio di fenomeni franosi può essere realizzato a diverse scale e con diverse tecnologie, ma negli ultimi decenni le metodologie geofisiche sono state largamente utilizzate per questo scopo, grazie alla peculiarità di essere non invasive e di poter rilevare la variazione di parametri fisici in un volume di terreno. Per quanto riguarda le frane superficiali, analizzate in questo studio, uno dei fattori predisponenti per l’attivazione è l’apporto precipitativo, che va a determinare variazioni nel contenuto d’acqua del suolo e nella pressione interstiziale. Diversi ricercatori hanno constatato l’utilità di misure geoelettriche per la valutazione del contenuto idrico nel corpo di frane superficiali (Perrone et al., 2008; De Bari et al., 2011; Ravindran e Prabhu., 2012) e in alcuni casi è stato predisposto un sistema di monitoraggio in continuo (Supper et al., 2008; Kuras et al., 2009; Hilbich et al., 2011). L’obiettivo di questo studio è quello di valutare, partendo dalla sperimentazione di laboratorio, l’applicabilità di un monitoraggio geoelettrico nel riconoscimento di un livello soglia di contenuto d’acqua per l’instaurarsi dell’instabilità di una frana superficiale

Effect of a quality improvement program on compliance to the sepsis bundle in non-ICU patients: a multicenter prospective before and after cohort study

ObjectiveSepsis and septic shock are major challenges and economic burdens to healthcare, impacting millions of people globally and representing significant causes of mortality. Recently, a large number of quality improvement programs focused on sepsis resuscitation bundles have been instituted worldwide. These educational initiatives have been shown to be associated with improvements in clinical outcomes. We aimed to evaluate the impact of a multi-faceted quality implementing program (QIP) on the compliance of a “simplified 1-h bundle” (Sepsis 6) and hospital mortality of severe sepsis and septic shock patients out of the intensive care unit (ICU).MethodsEmergency departments (EDs) and medical wards (MWs) of 12 academic and non-academic hospitals in the Lombardy region (Northern Italy) were involved in a multi-faceted QIP, which included educational and organizational interventions. Patients with a clinical diagnosis of severe sepsis or septic shock according to the Sepsis-2 criteria were enrolled in two different periods: from May 2011 to November 2011 (before-QIP cohort) and from August 2012 to June 2013 (after-QIP cohort).Measurements and main resultsThe effect of QIP on bundle compliance and hospital mortality was evaluated in a before–after analysis. We enrolled 467 patients in the before-QIP group and 656 in the after-QIP group. At the time of enrollment, septic shock was diagnosed in 50% of patients, similarly between the two periods. In the after-QIP group, we observed increased compliance to the “simplified rapid (1 h) intervention bundle” (the Sepsis 6 bundle – S6) at three time-points evaluated (1 h, 13.7 to 18.7%, p = 0.018, 3 h, 37.1 to 48.0%, p = 0.013, overall study period, 46.2 to 57.9%, p < 0.001). We then analyzed compliance with S6 and hospital mortality in the before- and after-QIP periods, stratifying the two patients’ cohorts by admission characteristics. Adherence to the S6 bundle was increased in patients with severe sepsis in the absence of shock, in patients with serum lactate <4.0 mmol/L, and in patients with hypotension at the time of enrollment, regardless of the type of admission (from EDs or MWs). Subsequently, in an observational analysis, we also investigated the relation between bundle compliance and hospital mortality by logistic regression. In the after-QIP cohort, we observed a lower in-hospital mortality than that observed in the before-QIP cohort. This finding was reported in subgroups where a higher adherence to the S6 bundle in the after-QIP period was found. After adjustment for confounders, the QIP appeared to be independently associated with a significant improvement in hospital mortality. Among the single S6 procedures applied within the first hour of sepsis diagnosis, compliance with blood culture and antibiotic therapy appeared significantly associated with reduced in-hospital mortality.ConclusionA multi-faceted QIP aimed at promoting an early simplified bundle of care for the management of septic patients out of the ICU was associated with improved compliance with sepsis bundles and lower in-hospital mortality

Sperimentazione di un sistema di monitoraggio elettrico permanente per la valutazione della vulnerabilità dei rilevati arginali in terra

Il lavoro svolto nell’ambito di questa tesi ha come obiettivo quello di fornire uno strumento di valutazione in continuo della vulnerabilità dei rilevati arginali in terra, ad ora non esistente. Utilizzando i dati provenienti dal monitoraggio di lungo periodo da parte di un geo-resistivimetro progettato ad hoc ed installato nel sito d’indagine, è stato possibile valutare il regime di filtrazione che interessa la struttura nei vari periodi dell’anno, valutando la relazione tra resistività, livello del canale e forzanti meteorologiche. Grazie alla realizzazione di un carotaggio è stato quindi possibile calibrare una curva che ha legato i valori di resistività a quelli di contenuto d’acqua, in modo da poter relazionare il valore di resistività a seguito di inversione con la saturazione del suolo. I risultati ottenuti grazie allo studio delle dipendenze reciproche tra le variabili in gioco, oltre ad aver fornito importanti informazioni sulle dinamiche che interessano la resistività in prospezioni superficiali, ha fatto sì che si potesse ottenere un quadro della situazione interna dell’argine, solitamente sconosciuta. I dati provenienti dal monitoraggio, dalle ricerche e dalle analisi effettuate, possono quindi essere utilizzati per effettuare delle simulazioni di filtrazione all’interno del rilevato. L’obiettivo dello studio è quello di fornire un metodo integrato per effettuare una valutazione di stabilità della struttura arginale facendo ricorso ai dati di monitoraggio in continuo della stazione installata nel sito d’indagine, correlati e depurati dalle influenze delle altre variabili in gioco

A customized resistivity system for monitoring saturation and seepage in earthen levees: installation and validation

This work is based on the assumption that a resistivity meter can effectively monitor water saturation in earth levees and can be used as a warning system when saturation exceeds the expected seasonal maxima. We performed time-lapse ERT measurements to assess the capability of this method to detect areas where seepage is critical. These measurements were also very useful to design a prototype monitoring system with remarkable savings by customizing the specifications according to field observations. The prototype consists of a remotely controlled low-power resistivity meter with a spread of 48 stainless steel 20 × 20 cm plate electrodes buried at half-meter depth. We deployed the newly-designed permanent monitoring system on a critical levee segment. A weather station and an ultrasonic water level sensor were also installed in order to analyse the correlation of resistivity with temperature, rainfalls and water level seasonal variations

Investigation on the Role of Water for the Stability of Shallow Landslides—Insights from Experimental Tests

Shallow soil slips are a significant hydrogeological hazard which could affect extended areas of the high-gradient mountainous landscape. Their triggering is highly dependent on the rainfall water infiltration and its further redistribution, as well as the characteristic properties of the soil itself. The complex interaction between those factors generates a considerable degree of uncertainty in the understanding of the governing processes. In this work, we take a small step further towards the untangling of those intricate relationships through observation. The results of a set of 20 downscaled shallow land mass failures are analysed through a principal component analysis and a further detailed look at the resulting parametric trends. Moreover, electrical resistivity tomography measurements are added up to the interpretation of experimental data, by providing a glimpse on the rainfall water infiltration process at the subsurface level. The outcome of this work implies that the coupled interaction between rainfall intensity, hydraulic conductivity and soil moisture gradient is governing the stability of soil and while rainfall intensity and duration are essential instability predictors, they must be integrated with antecedent moisture and site-specific characteristics. A tentative comparison of the dataset with existing rainfall thresholds for shallow landslide occurrence suggests the potential application of experimental tests for thresholds’ definition or validation under the appropriate dimensional analysis. A dimensional analysis indicated the interconnection of parameters intrinsic to the problem, and the significance of scale effects in performing a downscaled simulation of land mass failure

Bivalirudin or heparin in patients undergoing invasive management of acute coronary syndromes

Background: Contrasting evidence exists on the comparative efficacy and safety of bivalirudin and unfractionated heparin (UFH) in relation to the planned use of glycoprotein IIb/IIIa inhibitors (GPIs). Objectives: This study assessed the efficacy and safety of bivalirudin compared with UFH with or without GPIs in patients with acute coronary syndrome (ACS) who underwent invasive management. Methods: In the MATRIX (Minimizing Adverse Haemorrhagic Events by Transradial Access Site and Systemic Implementation of AngioX) program, 7,213 patients were randomly assigned to receive either bivalirudin or UFH with or without GPIs at discretion of the operator. The 30-day coprimary outcomes were major adverse cardiovascular events (MACEs) (a composite of death, myocardial infarction, or stroke), and net adverse clinical events (NACEs) (a composite of MACEs or major bleeding). Results: Among 3,603 patients assigned to receive UFH, 781 (21.7%) underwent planned treatment with GPI before coronary intervention. Bailout use of GPIs was similar between the bivalirudin and UFH groups (4.5% and 5.4%) (p = 0.11). At 30 days, the 2 coprimary endpoints of MACEs and NACEs, as well as individual endpoints of mortality, myocardial infarction, stent thrombosis or stroke did not differ among the 3 groups after adjustment. Compared with the UFH and UFH+GPI groups, bivalirudin reduced bleeding, mainly the most severe bleeds, including fatal and nonaccess site−related events, as well as transfusion rates and the need for surgical access site repair. These findings were not influenced by the administered intraprocedural dose of UFH and were confirmed at multiple sensitivity analyses, including the randomly allocated access site. Conclusions: In patients with ACS, the rates of MACEs and NACEs were not significantly lower with bivalirudin than with UFH, irrespective of planned GPI use. However, bivalirudin significantly reduced bleeding complications, mainly those not related to access site, irrespective of planned use of GPIs. (Minimizing Adverse Haemorrhagic Events by Transradial Access Site and Systemic Implementation of AngioX [MATRIX]; NCT01433627