Effects of Vertical Seismic Accelerations on Slope Displacements

The behaviour of earth slopes under seismic conditions can be effectively studied by evaluating the suffered displacements, which are key parameters in the recent performance design approaches (Pianc/PTCII/WG34, 2001). Different methodologies have been developed to evaluate displacements (Whitman, 1993). Slope instabilities caused by yielding due to seismic inertial forces can be studied by methods based on the well-known model of a rigid block sliding on a plane surface (Newmark 1965). These methodologies utilise accelerometric time histories which allow to take into account the real characteristics of the seismic motion (Simonelli and Viggiani 1995). Displacement analyses are traditionally performed adopting only horizontal accelerograms. The aim of this paper is to evaluate the effects of vertical components of seismic motions. In this case, the critical acceleration depends on the direction of the resulting motion (Sarma 1975, 1999). The analyses have been performed for three major Italian earthquakes. The case of an indefinite slope in dry cohesionless soil has been examined. The results of the analyses have been synthesised in diagrams, which show that the displacement variations induced by vertical accelerations are negligible for the range of displacements values (of the order of centimetres), which are of interest from an engineering point of view

Size and age at onset of sexual maturity of female Norway lobster Nephrops norvegicus L. (Crustacea: Nephropidae) in the Strait of Sicily (Central Mediterranean Sea)

The reproductive cycle of the Norway lobster (Nephrops norvegicus) female was investigated to determine the size and age at onset of sexual maturity (SOM), as a baseline to establish the minimum catchable size. Samples were gathered in four seasonal (Spring 1986 - Winter 1987) trawl surveys on the Italian side of the Strait of Sicily (Central Mediterranean Sea). The relative frequency of females in different stages of maturation and in berried conditions was observed. According to the ovary stages, gonadal maturation is attained during Spring and Summer; berried animals occur almost exclusively in Summer and Autumn, in about 40% of the sample. Length structure changes slightly by location and by season; recruitment to the gear occurs more or less continuously. Gaussian components appear to be highly overlapped; the resolution of the length frequency distribution values leads to the identification of multiple cohorts, five of which were well represented. The population attains 50% of maturity at 30-32 mm CL, corresponding to an age of 5 years. The mean size of the first Gaussian component from the catch (about 22 mm CL) is well below the estimated size at 50% maturity, suggesting a precocious recruitment to the fishery.No disponibl

Understanding karst environments by thermo-hygrometric monitoring: preliminary results from the Cesi Mountain karst system (Central Italy)

The understanding of karst systems is of paramount importance for the protection and valorisation of these environments. A multidisciplinary study is presented to investigate the possible interconnection between karst features of a karst area located in the south-western part of the Martani chain (Cesi Mountain, Central Italy). This hydrogeological structure contributes to recharge a deep regional aquifer. The latter feeds the high discharge and salinity Stifone springs. In the southwestern part of Martani chain, seven caves have been mapped, five of which are hosted in the Calcare Massiccio Formation. The analysis of thermo-hygrometric data collected since Autumn 2014 into the caves and those from external meteorological stations, showed the timing of the airflow inversion occurring on late winter/early spring and summer/ early autumn. Despite the complexity of the morphology of caves and of conceptual models of airflow pattern, these data seem to indicate that the monitored small caves could be interconnected to a considerably wider cave system. Data here presented coupled with the knowledge on hydrogeological and geological-structural setting of the limestone massif are useful to drive future speleological explorations, aiming to discover new large cavities and to better understand the water recharge process

Discharge variations of springs induced by strong earthquakes: the case of the mw 6.5 Norcia event (Italy, October 30 th 2016)

Earthquakes, dynamic strain, groundwater circulation, structural permeability

POLARIX: a pathfinder mission of X-ray polarimetry

Since the birth of X-ray astronomy, spectral, spatial and timing observation improved dramatically, procuring a wealth of information on the majority of the classes of the celestial sources. Polarimetry, instead, remained basically unprobed. X-ray polarimetry promises to provide additional information procuring two new observable quantities, the degree and the angle of polarization. POLARIX is a mission dedicated to X-ray polarimetry. It exploits the polarimetric response of a Gas Pixel Detector, combined with position sensitivity, that, at the focus of a telescope, results in a huge increase of sensitivity. Three Gas Pixel Detectors are coupled with three X-ray optics which are the heritage of JET-X mission. POLARIX will measure time resolved X-ray polarization with an angular resolution of about 20 arcsec in a field of view of 15 arcmin $\times$ 15 arcmin and with an energy resolution of 20 % at 6 keV. The Minimum Detectable Polarization is 12 % for a source having a flux of 1 mCrab and 10^5 s of observing time. The satellite will be placed in an equatorial orbit of 505 km of altitude by a Vega launcher.The telemetry down-link station will be Malindi. The pointing of POLARIX satellite will be gyroless and it will perform a double pointing during the earth occultation of one source, so maximizing the scientific return. POLARIX data are for 75 % open to the community while 25 % + SVP (Science Verification Phase, 1 month of operation) is dedicated to a core program activity open to the contribution of associated scientists. The planned duration of the mission is one year plus three months of commissioning and SVP, suitable to perform most of the basic science within the reach of this instrument.Comment: 42 pages, 28 figure

Insight into the mechanism of ferroptosis inhibition by ferrostatin-1

Ferroptosis is a form of cell death primed by iron and lipid hydroperoxides and prevented by GPx4. Ferrostatin-1 (fer-1) inhibits ferroptosis much more efficiently than phenolic antioxidants. Previous studies on the antioxidant efficiency of fer-1 adopted kinetic tests where a diazo compound generates the hydroperoxyl radical scavenged by the antioxidant. However, this reaction, accounting for a chain breaking effect, is only minimally useful for the description of the inhibition of ferrous iron and lipid hydroperoxide dependent peroxidation. Scavenging lipid hydroperoxyl radicals, indeed, generates lipid hydroperoxides from which ferrous iron initiates a new peroxidative chain reaction. We show that when fer-1 inhibits peroxidation, initiated by iron and traces of lipid hydroperoxides in liposomes, the pattern of oxidized species produced from traces of pre-existing hydroperoxides is practically identical to that observed following exhaustive peroxidation in the absence of the antioxidant. This supported the notion that the anti-ferroptotic activity of fer-1 is actually due to the scavenging of initiating alkoxyl radicals produced, together with other rearrangement products, by ferrous iron from lipid hydroperoxides. Notably, fer-1 is not consumed while inhibiting iron dependent lipid peroxidation. The emerging concept is that it is ferrous iron itself that reduces fer-1 radical. This was supported by electroanalytical evidence that fer-1 forms a complex with iron and further confirmed in cells by fluorescence of calcein, indicating a decrease of labile iron in the presence of fer-1. The notion of such as pseudo-catalytic cycle of the ferrostatin-iron complex was also investigated by means of quantum mechanics calculations, which confirmed the reduction of an alkoxyl radical model by fer-1 and the reduction of fer-1 radical by ferrous iron. In summary, GPx4 and fer-1 in the presence of ferrous iron, produces, by distinct mechanism, the most relevant anti-ferroptotic effect, i.e the disappearance of initiating lipid hydroperoxides

Double carbapenem as a rescue strategy for the treatment of severe carbapenemase-producing Klebsiella pneumoniae infections: A two-center, matched case-control study

Background: Recent reports have suggested the efficacy of a double carbapenem (DC) combination, including ertapenem, for the treatment of carbapenem-resistant Klebsiella pneumoniae (CR-Kp) infections. We aimed to evaluate the clinical impact of such a regimen in critically ill patients. Methods: This case-control (1:2), observational, two-center study involved critically ill adults with a microbiologically documented CR-Kp invasive infection treated with the DC regimen matched with those receiving a standard treatment (ST) (i.e., colistin, tigecycline, or gentamicin). Results: The primary end point was 28-day mortality. Secondary outcomes were clinical cure, microbiological eradication, duration of mechanical ventilation and of vasopressors, and 90-day mortality. Forty-eight patients treated with DC were matched with 96 controls. Occurrence of septic shock at infection and high procalcitonin levels were significantly more frequent in patients receiving DC treatment (p < 0.01). The 28-day mortality was significantly higher in patients receiving ST compared with the DC group (47.9% vs 29.2%, p = 0.04). Similarly, clinical cure and microbiological eradication were significantly higher when DC was used in patients infected with CR-Kp strains resistant to colistin (13/20 (65%) vs 10/32 (31.3%), p = 0.03 and 11/19 (57.9%) vs 7/27 (25.9%), p = 0.04, respectively). In the logistic regression and multivariate Cox-regression models, the DC regimen was associated with a reduction in 28-day mortality (OR 0.33, 95% CI 0.13-0.87 and OR 0.43, 95% CI 0.23-0.79, respectively). Conclusions: Improved 28-day mortality was associated with the DC regimen compared with ST for severe CR-Kp infections. A randomized trial is needed to confirm these observational results. Trial registration: ClinicalTrials.gov NCT03094494. Registered 28 March 2017

Chroman-4-One Derivatives Targeting Pteridine Reductase 1 and Showing Anti-Parasitic Activity

Flavonoids have previously been identified as antiparasitic agents and pteridine reductase 1 (PTR1) inhibitors. Herein, we focus our attention on the chroman-4-one scaffold. Three chroman-4-one analogues (1-3) of previously published chromen-4-one derivatives were synthesized and biologically evaluated against parasitic enzymes (Trypanosoma brucei PTR1-TbPTR1 and Leishmania major-LmPTR1) and parasites (Trypanosoma brucei and Leishmania infantum). A crystal structure of TbPTR1 in complex with compound 1 and the first crystal structures of LmPTR1-flavanone complexes (compounds 1 and 3) were solved. The inhibitory activity of the chroman-4-one and chromen-4-one derivatives was explained by comparison of observed and predicted binding modes of the compounds. Compound 1 showed activity both against the targeted enzymes and the parasites with a selectivity index greater than 7 and a low toxicity. Our results provide a basis for further scaffold optimization and structure-based drug design aimed at the identification of potent anti-trypanosomatidic compounds targeting multiple PTR1 variants