Occupations at risk and organizational well-being: an empirical test of a Job Insecurity Integrated Model

One of the more visible effects of the societal changes is the increased feelings of uncertainty in the workforce. In fact, job insecurity represents a crucial occupational risk factor and a major job stressor that has negative consequences on both organizational well-being and individual health. Many studies have focused on the consequences about the fear and the perception of losing the job as a whole (called quantitative job insecurity), while more recently research has begun to examine more extensively the worries and the perceptions of losing valued job features (called qualitative job insecurity). The vast majority of the studies, however, have investigated the effects of quantitative and qualitative job insecurity separately. In this paper, we proposed the Job Insecurity Integrated Model aimed to examine the effects of quantitative job insecurity and qualitative job insecurity on their short-term and long-term outcomes. This model was empirically tested in two independent studies, hypothesizing that qualitative job insecurity mediated the effects of quantitative job insecurity on different outcomes, such as work engagement and organizational identification (Study 1), and job satisfaction, commitment, psychological stress and turnover intention (Study 2). Study 1 was conducted on 329 employees in private firms, while Study 2 on 278 employees in both public sector and private firms. Results robustly showed that qualitative job insecurity totally mediated the effects of quantitative on all the considered outcomes. By showing that the effects of quantitative job insecurity on its outcomes passed through qualitative job insecurity, the Job Insecurity Integrated Model contributes to clarifying previous findings in job insecurity research and puts forward a framework that could profitably produce new investigations with important theoretical and practical implications

Augmented GNSS Differential Corrections Minimum Mean Square Error Estimation Sensitivity to Spatial Correlation Modeling Errors

Railway signaling is a safety system that has evolved over the last couple of centuries towards autonomous functionality. Recently, great effort is being devoted inthis field, towards the use and exploitation of Global Navigation Satellite System (GNSS)signals and GNSS augmentation systems in view of lower railway track equipments andmaintenance costs, that is a priority to sustain the investments for modernizing the local andregional lines most of which lack automatic train protection systems and are still manuallyoperated. The objective of this paper is to assess the sensitivity of the Linear Minimum MeanSquare Error (LMMSE) algorithm to modeling errors in the spatial correlation function thatcharacterizes true pseudorange Differential Corrections (DCs). This study is inspired bythe railway application; however, it applies to all transportation systems, including the roadsector, that need to be complemented by an augmentation system in order to deliver accurateand reliable positioning with integrity specifications. A vector of noisy pseudorange DCmeasurements are simulated, assuming a Gauss-Markov model with a decay rate parameterinversely proportional to the correlation distance that exists between two points of a certainenvironment. The LMMSE algorithm is applied on this vector to estimate the true DC, andthe estimation error is compared to the noise added during simulation. The results show thatfor large enough correlation distance to Reference Stations (RSs) distance separation ratiovalues, the LMMSE brings considerable advantage in terms of estimation error accuracy and precision. Conversely, the LMMSE algorithm may deteriorate the quality of the DCmeasurements whenever the ratio falls below a certain threshold

Stability Analysis of the Serchio River Flood Plain Embankments (Tuscany, Italy)

Following the geotechnical characterization of 30 km long flood - plain embankments of the Serchio River (Tuscany – Italy), a number of numerical analyses have been carried out. The embankments have been constructed since the XVIII century and have experienced several failures in the years (the last in December 2009). The geotechnical characterization of the river embankments and the 2009 flood are described in a companion paper in this Conference. This paper shows the results of numerical analyses that have been carried out for various purposes. More specifically, the numerical analyses were carried out a) to clarify the causes of the December 2009 failures, b) to design appropriate repair of the failures and retrofit of the embankments in proximity of the failures (about 6 km) and c) to identify the most risk areas considering the whole extension of the embankments (30 km). The limit equilibrium method was used to assess the stability of the embankments under steady state flow conditions (areas close to the failures). For this analysis three different types of commercial software were used. The stability analyses were carried out using the Bishop simplified method with circular sliding surfaces. The different codes indicated very similar failure surfaces corresponding to the minimum (meaningful) values of the global safety factor. Some differences on the values of the global safety factor were observed by comparing the results obtained from the three codes. More specifically, the analyses results show that, for the selected cross sections, the safety factors are rather small and approaching to unity, if the seepage forces are not considered. In the case of steady state flow, safety factor drastically reduces becoming lower than one. This result apparently contradicts the fact that the considered embankments are standing up since centuries and failures occurred only in the occasion of floods. The FEM analysis (PLAXIS Flow) shows that the safety margins of the considered sections, in absence of filtration, are assigned to the partial saturation of the embankment. Unfortunately, an appropriate characterization of the material under conditions of partial saturation was not available. Therefore, the FEM analyses were also aimed at determining the necessary time to approach the steady state flow conditions. For the case under consideration it was estimated that 10 days are necessary to approach the steady state flow conditions. This time is apparently much longer than the duration of the longest flood event (few hours). From the above it is possible to conclude that the hypothesis of permanent flow is generally too cautious. Anyway for the failures under consideration, that have occurred with the concurrence of various adverse factors like the melting of the snow because of a sudden temperature increase and the contemporary long raining period (two consecutive floods), it is reasonable to assume that the permanent flow conditions were probably reached. In addition to the numerical analyses, evidences of the considered event and the susceptibility of the analyzed soil to piping phenomena have also been considered to find out all the possible causes and to design in an appropriate way both repair of the failures and retrofitting of the surrounding areas. Assessment of the most risky areas, considering the whole extension of the embankments (30 km), has been carried out following expeditious criteria which were based on the embankment geometry and the mechanical soil characteristics

Geotechnical Characterization of the Flood Plain Embankments of the Serchio River (Tuscany, Italy)

The flood plain embankments of the Serchio river have been constructed since the XVIII century and construction details are not known. These embankments have experienced failures several times during their life (last in December 2009). After the last event a detailed geotechnical investigation has been carried out. This paper discusses the necessary criteria for a cost – effective campaign considering the total length of the embankments (30 km) and the requested level of detail. In fact levee failure, although it is of limited extension, causes the achievement of the ultimate limit state of the entire embankment system. The campaign, in addition to laboratory tests, included boreholes, CPTu, permeability tests, 2D geo-electric tomography and 15 tests performed by the use of the continuous core drilling system. This last has proved to be a very useful tool for obtaining the more accurate evaluation of the in situ soil density (as confirmed by CPTu results). CPTu test, economical and expeditious, has proved to be an indispensable tool for delineating soil stratigraphy. In fact, their results combined with the borehole logs and laboratory testing provide extensive information. Geo-electric investigations can be very useful to highlight anomalies and heterogeneities in the cross section. Eventually, it is worthwhile to stress that embankments have generally a height of less than 4 m and a width between 1.2 and 3 m. This has restricted the investigation tools that could be used in this peculiar case

Spatial extent of recent vertical tectonic motions misured in NE Sicily coastal area. Insights from marine geology and coastal geomorphology studies.

Vertical position of sea-level, pointed out by related deposits and morphologies, provide useful markers to estimate tectonic uplift rates. For the Holocene very high uplift rates are misured in the northeast Sicily coast (Antonioli et al., 2009). This study compare vertical tectonic movements and marine geology data in the coastal sector between Capo d\u2019Orlando and Brolo (NE Sicily); tectonic lineaments show different trends both onland (Nigro & Sulli, 1995) and offshore (Nicolich et al.,1982) and also the morphological response follow closely this difference. The geomorphologic survey provided data on Holocene uplift rates. We studied an archaeological ancient quarry of grinding wheels for oil that has been found in the Capo d\u2019Orlando inshore (Scicchitano et al., 2011). They present semi submerged circular holes in Stilo-Capo d\u2019Orlando deposits (Carbone et al., 1998). The tectonic uplift was evaluated as the difference between the observed local paleo-sea level position and the predicted sea-level curve for the same locality (Lambeck et al., 2011). The resulting uplift rates is 0.36 mm/yr (Scicchitano et al., 2011). In this area we studied also the Brolo stack. It is a metamorphic rocks emerging at 450 m from the coastline. The study led to discovery a fossils-bearing conglomerate in protected trays at 3.5 m a.s.l.. Radiocarbon analysis on a gastropod, gave us an age of 4965 years +-70 cal BP. If we compare this data with the predicted local sea level curves (Lambeck et al., 2011), we obtain an uplift rate about 1.5 mm/yr (Lo Presti et al., 2010), which is higher than that calculated in the study of archaeological rest. A detailed study of Brolo sector show us different morphological coastline position of Brolo plain. A picture of the year 1847 shows the coastline about 200 m landward. In Brolo coastal plain we have also found a Spondylus at -6 m b.s.l. We wait for the radiocarbon dating which allows us to have a new uplift rate data. The analysis of marine geology data (Multibeam) evidenced structures connected to different faults systems, such as the submarine canyons that are the continuation of river beds. Multibeam data evidenced also tilted NE-ward submerged surfaces, indicating existing structural movements, interesting only restricted areas. So, very different uplift rates in the Holocene in very close areas distant only about 10 kilometers: both 0.36 mm/yr (Scicchitano et al. 2011) and 1.5 mm/yr (Lo Presti et al. 2010), and morphobathymetric data (tilted surfaces), evidence the important role of active tectonic lineaments. Seismic reflection profiles support this assumption, showing the metamorphic basement strongly dissected by high-angle faults, which at place determines the occurrence of emergent rock bodies (e.g. the Brolo stack). All this suggesting the occurrence of \u201crestricted regions\u201d in the coastal-marine sector with different geological behavior as response to prominent tectonic releasing bands, determining their horizontal and vertical movements

Low Power Front End for the Optical Module of a Neutrino Underwater Telescope

A proposal for a new system to capture signals in the Optical Module (OM) of an underwater neutrino telescope is described. It concentrates on the problem of power consumption and time precision. In particular, a solution for the interface between the photomultiplier (PMT) and the front-end electronics is presented

On the molecular basis of the activity of the antimalarial drug chloroquine : EXAFS-assisted DFT evidence of a direct Fe–N bond with free heme in solution

4-aminoquinoline antiplasmodials interfere with the biocrystallization of the malaria pigment, a key step of the malaria parasite metabolism. It is commonly believed that these drugs set stacking \u3c0 \ub7\ub7\ub7 \u3c0 interactions with the Fe-protoporphyrin scaffold of the free heme, even though the details of the heme:drug recognition process remain elusive. In this work, the local coordination of Fe(III) ions in acidic solutions of hematin at room temperature was investigated by extended x-ray absorption fine structure (EXAFS) spectroscopy in the 4.0\u20135.5 pH range, both in the presence and in the absence of the antimalarial drug chloroquine. EXAFS results were complemented by DFT simulations in polarizable continuum media to model solvent effects. We found evidence that a complex where the drug quinoline nitrogen is coordinated with the iron center might coexist with formerly proposed adduct geometries, based on stacking interactions. Charge-assisted hydrogen bonds among lateral chains of the two molecules play a crucial role in stabilizing this complex, whose formation is favored by the presence of lipid micelles. The direct Fe\u2013N bond could reversibly block the axial position in the Fe 1st coordination shell in free heme, acting as an inhibitor for the crystallization of the malaria pigment without permanently hampering the catalytic activity of the redox center. These findings are discussed in the light of possible implications on the engineering of drugs able to thwart the adaptability of the malaria parasite against classical aminoquinoline-based therapies

Comparing marine geology and coastal geomorphology vertical tectonic data, a case study between Acquedolci and Patti (Messina).

The study of new data on vertical movements show a complex geologic response in a restricted sector of coastal area between Acquedolci and Patti (north-eastern Sicily). Different surveys allowed to the recognition of morphological, biological and archaeological markers of paleo-sea level. The analysis of these markers and the absolute datings performed, allowed to reconstruct the history of vertical deformation of this sector but only the comparison among coastal geomorphological data and marine geological data of platform-scarp continental system associates, allowed to find the necessary keys words to explain the geologic complexity of this sector