377 research outputs found
Efficienza dei servizi sanitari ed utilizzo ottimale delle risorse. Una applicazione al Policlinico Universitario di Cagliari
l’applicazione del nomogramma di Barber, che può essere impiegato nel controllo della gestione di un dato reparto ospedaliero considerando le diverse
patologie (DRG) che ad esso afferiscono sia per effettuare analisi di tipo descrittivo e/o investigativo relativamente ai singoli DRG sia per
condurre indagini diacroniche finalizzate a cogliere quali siano state
le variazioni del livello di efficienza nel corso del tempo dei reparti
e/o delle varie patologie.
In ultima analisi l’utilizzazione del modello quale strumento di valutazione della gestione delle attività sanitarie
Spatial Distribution and Air-Water Exchange of Organic Flame Retardents in the Lower Great Lakes
Organic flame retardants (OFRs) such as polybrominated diphenyl ethers (PBDEs) and novel halogenated flame retardants (NHFRs) are ubiquitous, persistent, and bioaccumulative contaminants that have been used in consumer goods to slow combustion. In this study, polyethylene passive samplers (PEs) were deployed throughout the lower Great Lakes (Lake Erie and Lake Ontario) to measure OFRs in air and water, calculate air–water exchange fluxes, and investigate spatial trends. Dissolved Σ12BDE was greatest in Lake Ontario near Toronto (18 pg/L), whereas gaseous Σ12BDE was greatest on the southern shoreline of Lake Erie (11 pg/m3). NHFRs were generally below detection limits. Air–water exchange was dominated by absorption of BDEs 47 and 99, ranging from −964 pg/m2/day to −30 pg/m2/day. Σ12BDE in air and water was significantly correlated with surrounding population density, suggesting that phased-out PBDEs continued to be emitted from population centers along the Great Lakes shoreline in 2012. Correlation with dissolved Σ12BDE was strongest when considering population within 25 km while correlation with gaseous Σ12BDE was strongest when using population within 3 km to the south of each site. Bayesian kriging was used to predict dissolved Σ12BDE over the lakes, illustrating the utility of relatively highly spatially resolved measurements in identifying potential hot spots for future study
Climate Alters the Migration Phenology of Coastal Marine Species
Significant shifts in the phenology of life-cycle events have been observed in diverse taxa throughout the global oceans. While the migration phenology of marine fish and invertebrates is expected to be sensitive to climate change, the complex nature of these patterns has made measurement difficult and studies rare. With continuous weekly observations spanning 7 decades in Narragansett Bay, Rhode Island (USA), the University of Rhode Island Graduate School of Oceanography trawl survey provides an unprecedented opportunity to investigate the influence of climate on the migrations of marine species in the northwest Atlantic. Analyses of the survey observations of 12 species indicated that residence periods have changed by as much as 118 d, with shifts in the timing of both ingress to and egress from the coastal zone. The residence periods of warm-water species expanded while those of cold-water species contracted. Dirichlet regressions fit to the annual presence-absence patterns of each species identified interannual temperature variations, fluctuations in ocean circulation, and long-term warming all as having a significant effect on migration phenology. Additionally, temperature gradients within Narragansett Bay were shown by generalized additive models to cause detectable shifts in local spatial distributions during coastal residency. These novel findings mirror results found in the spatial domain and therefore suggest that the studied species are adapting their spatiotemporal distributions to track their thermal niche in a changing climate. If so, characterizing the spatial and temporal aspects of climate responses across species will be critical to understanding ongoing changes in marine ecosystems and successfully managing the fisheries they support
Ammonium recovery from agro-industrial digestate using bioelectrochemical systems
Abstract
Growing food and biomass production at the global scale has determined a corresponding increase in the demand for and use of nutrients. In this study, the possibility of recovering nitrogen from agro-industrial digestate using bioelectrochemical systems was investigated: two microbial electrolysis cells (MECs) were fed with synthetic and real digestate (2.5 gNH4+-N L−1). Carbon felt and granular graphite were used as anodes in MEC-1 and MEC-2, respectively. As to synthetic wastewater, the optimal nitrogen load (NL) for MEC-1 and -2 was 1.25 and 0.75 gNH4+-N d−1, respectively. MEC-1 showed better performance in terms of NH4+-N removal efficiency (39 ± 2.5%) and recovery rate (up to 70 gNH4+-N m−2d−1), compared to MEC-2 (33 ± 4.7% and up to 30 gN m−2d−1, respectively). At the optimal hydraulic retention time, lower NH4+-N removal efficiencies and recovery rates were observed when real digestate was fed to MEC-1 (29 ± 6.6% and 60 ± 13 gNH4+-N m−2d−1, respectively) and MEC-2 (21 ± 7.9% and 10 ± 3.6 gNH4+-N m−2d−1, respectively), likely due to the higher complexity of the influent. The average energy requirements were 3.6–3.7 kWh kgNremoved−1, comparable with values previously reported in the literature and lower than conventional ammonia recovery processes. Results are promising and may reduce the need for costly and polluting processes for nitrogen synthesis
Exchange interactions and magnetic phases of transition metal oxides: benchmarking advanced ab initio methods
The magnetic properties of the transition metal monoxides MnO and NiO are
investigated at equilibrium and under pressure via several advanced
first-principles methods coupled with Heisenberg Hamiltonian MonteCarlo. The
comparative first-principles analysis involves two promising beyond-local
density functionals approaches, namely the hybrid density functional theory and
the recently developed variational pseudo-self-interaction correction method,
implemented with both plane-wave and atomic-orbital basis sets. The advanced
functionals deliver a very satisfying rendition, curing the main drawbacks of
the local functionals and improving over many other previous theoretical
predictions. Furthermore, and most importantly, they convincingly demonstrate a
degree of internal consistency, despite differences emerging due to
methodological details (e.g. plane waves vs. atomic orbitals
Fermi-surface pockets in magnetic underdoped cuprates from first principles
Using an innovative first-principles band theory enabling the exploration of
Mott-insulating magnetic cuprates, we study the Fermi surface of underdoped
YCaBaCuO in a selection of magnetically ordered and
polaronic states. All phases exhibit qualitatively similar, hole-like
nodal-point small pockets. Their properties (area, masses, mass sign) only
partially match those extracted from recent quantum-oscillation experiments. Ab
initio calculations, therefore, do not straightforwardly support a magnetic
origin of quantum oscillations.Comment: 4 pages, 4 figure
Double row spacing and drip irrigation as technical options in energy sorghum management
The effect of two row spacing configurations and four water supply levels was investigated on sweet and fibre sorghum in Central Italy for two consecutive years. Results highlighted the influence of both irrigation and row spatial configuration on crop productivity. Indeed, several studies have pointed out the positive response of sorghum to irrigation in Mediterranean climate, as in this environment water stress represents one of the main limiting factors on crop productivity. On the other hand, few attempts have been made to explore the role of row spacing on energy sorghum productivity. Results outlined an average increase in sorghum dry biomass yield ranging from +23% to +79% at variable rates of water supply as compared to rainfed control. The positive effect of irrigation was also observed on leaf area index and radiation use efficiency. Moreover, we observed a crop yield increase, from 9% to 20%, under double row spacing compared to the standard planting pattern ( i.e. single row spacing). Finally, it was confirmed the efficient use of water by sorghum and the great ability of sorghum to increase its biomass yield in response to increasing volumes of water supplied. Therefore, this work suggests how row spacing configuration and drip irrigation could be feasible technical options to increase sorghum biomass yields in Mediterranean environments. These techniques should be experienced by farmers towards a sustainable intensification of current cropping systems
Diazotroph Activity in Surface Narragansett Bay Sediments in Summer is Stimulated by Hypoxia and Organic Matter Delivery
Bacteria that carry out many processes of the nitrogen cycle inhabit estuarine sediments. Denitrification is known to be a dominant process causing estuarine sediments to behave as net nitrogen sinks. However, measurements of nitrogen fluxes in the sediments of Narragansett Bay, Rhode Island, USA, have at times revealed high rates of net nitrogen (N2) fixation. Whereas changes in primary production, in magnitude and phenology, within Narragansett Bay have been identified as possible causes for these changes in nitrogen cycling within the benthos, a factor that has not been examined thus far is seasonal hypoxia. Since anaerobic diazotrophs figure so prominently within the sediments of Narragansett Bay, we hypothesized that dissolved oxygen concentrations in the bottom waters affect their activity. In order to explore this relationship, we measured the activity of diazotrophs in the surface sediments of 3 study areas during the summers of 2013 and 2014 using the acetylene reduction assay. We explored the effects of several water quality parameters on nitrogenase activity including, among others, dissolved oxygen and chlorophyll concentrations. Our measurements of nitrogenase activity were generally low, ranging between 2 and 5 nmol ethylene g-1 d-1 but spiked to 16 nmol ethylene g-1 d-1 at an area experiencing severe hypoxia in July 2013. Our data suggest that diazotrophy in estuarine sediments is enhanced when the benthos experiences very low dissolved oxygen in conjunction with recent influxes of autochthonous organic matter. Experiments with sediment core incubations conducted in the laboratory support our hypothesis that low dissolved oxygen and organic matter additions promote N2 fixation
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