Deciding the Criteria Is Not Enough: Moral Issues to Consider for a Fair Allocation of Scarce ICU Resources

During the first wave of the COVID-19 pandemic in Italy, practitioners had to make tragic decisions regarding the allocation of scarce resources in the ICU. The Italian debate has paid a lot of attention to identifying the specific regulatory criteria for the allocation of resources in the ICU; in this paper, however, we argue that deciding such criteria is not enough for the implementation of fair and transparent allocative decisions. In this respect, we discuss three ethical issues: (a) in the Italian context, the treating physician, rather than a separate committee, was generally the one responsible for the allocation decision; (b) although many allocative guidelines have supported moral equivalence between withholding and withdrawing treatments, some health professionals have continued to consider it a morally problematic aspect; and (c) the health workers who have had to make the aforementioned decisions or even only worked in ICU during the pandemic often experienced moral distress. We conclude by arguing that, even if these problems are not directly related to the above-mentioned issues of distributive justice, they can nevertheless directly affect the quality and ethics of the implementation of allocative criteria, regardless of those chosen

Is Left Ventricular Assist Device Deactivation Ethically Acceptable? A Study on the Euthanasia Debate

In the last decades, new technologies have improved the survival of patients affected by chronic illnesses. Among them, left ventricular assist device (LVAD) has represented a viable solution for patients with advanced heart failure (HF). Even though the LVAD prolongs life expectancy, patients' vulnerability generally increases during follow up and patients' request for the device withdrawal might occur. Such a request raises some ethical concerns in that it directly hastens the patient's death. Hence, in order to assess the ethical acceptability of LVAD withdrawal, we analyse and examine an ethical argument, widely adopted in the literature, that we call the "descriptive approach", which consists in giving a definition of life-sustaining treatment to evaluate the ethical acceptability of treatment withdrawal. Focusing attention on LVAD, we show criticisms of this perspective. Finally, we assess every patient's request of LVAD withdrawal through a prescriptive approach, which finds its roots in the criterion of proportionality

Deblurring of frequency-wavenumber images from small-scale seismic arrays

Temporary arrays installed in urban areas for investigating the upper-most geological structure typically comprised of a limited number of stations and are arranged in geometries constrained by environmental boundaries. Therefore, it is expected that the frequency–wavenumber images are significantly blurred by the array transfer function and are corrupted by noise. In this paper, the effect of theRichardson–Lucy regularization method applied to the problem of deblurring frequency–wavenumber images is investigated. The images are computed by analysing data from two small-aperture 2-D arrays, installed with different configurations in a test-site within the town of Potenza (Southern Italy) for near-surface investigations. We show that removing the effects of the array response from the frequency–wavenumber images improve the phase-velocity estimation, reducing the relevant level of uncertainty. Furthermore, the Richardson–Lucy regularization method is effective in reducing the level of noise related to spatial aliasing by eliminating spurious peaks, allowing the maxima related to different seismic sources to be better discriminated

Spin-phonon coupling effects in transition-metal perovskites:a DFT+UU and hybrid-functional study

Spin-phonon coupling effects, as reflected in phonon frequency shifts between ferromagnetic (FM) and G-type antiferromagnetic (AFM) configurations in cubic CaMnO$_3$, SrMnO$_3$, BaMnO$_3$, LaCrO$_3$, LaFeO$_3$ and La$_2$(CrFe)O$_6$, are investigated using density-functional methods. The calculations are carried out both with a hybrid-functional (HSE) approach and with a DFT+$U$ approach using a $U$ that has been fitted to HSE calculations. The phonon frequency shifts obtained in going from the FM to the AFM spin configuration agree well with those computed directly from the more accurate HSE approach, but are obtained with much less computational effort. We find that in the $A$MnO$_3$ materials class with $A$=Ca, Sr, and Ba, this frequency shift decreases as the A cation radius increases for the $\Gamma$ phonons, while it increases for R-point phonons. In La$M$O$_3$ with $M$=Cr, Fe, and Cr/Fe, the phonon frequencies at $\Gamma$ decrease as the spin order changes from AFM to FM for LaCrO$_3$ and LaFeO$_3$, but they increase for the double perovskite La$_2$(CrFe)O$_6$. We discuss these results and the prospects for bulk and superlattice forms of these materials to be useful as multiferroics.Comment: 13 pages, 7 figures, 9 table

Magneto-optics in pure and defective Ga_{1-x}Mn_xAs from first-principles

The magneto-optical properties of Ga$_{1-x}$Mn$_{x}$As including their most common defects were investigated with precise first--principles density-functional FLAPW calculations in order to: {\em i}) elucidate the origin of the features in the Kerr spectra in terms of the underlying electronic structure; {\em ii}) perform an accurate comparison with experiments; and {\em iii}) understand the role of the Mn concentration and occupied sites in shaping the spectra. In the substitutional case, our results show that most of the features have an interband origin and are only slightly affected by Drude--like contributions, even at low photon energies. While not strongly affected by the Mn concentration for the intermediately diluted range ($x\sim$ 10%), the Kerr factor shows a marked minimum (up to 1.5$^o$) occurring at a photon energy of $\sim$ 0.5 eV. For interstitial Mn, the calculated results bear a striking resemblance to the experimental spectra, pointing to the comparison between simulated and experimental Kerr angles as a valid tool to distinguish different defects in the diluted magnetic semiconductors framework.Comment: 10 pages including 2 figures, submitted to Phys. Rev.

The multiferroic phase of DyFeO3_{3}:an ab--initio study

By performing accurate ab-initio density functional theory calculations, we study the role of $4f$ electrons in stabilizing the magnetic-field-induced ferroelectric state of DyFeO$_{3}$. We confirm that the ferroelectric polarization is driven by an exchange-strictive mechanism, working between adjacent spin-polarized Fe and Dy layers, as suggested by Y. Tokunaga [Phys. Rev. Lett, \textbf{101}, 097205 (2008)]. A careful electronic structure analysis suggests that coupling between Dy and Fe spin sublattices is mediated by Dy-$d$ and O-$2p$ hybridization. Our results are robust with respect to the different computational schemes used for $d$ and $f$ localized states, such as the DFT+$U$ method, the Heyd-Scuseria-Ernzerhof (HSE) hybrid functional and the GW approach. Our findings indicate that the interaction between the $f$ and $d$ sublattice might be used to tailor ferroelectric and magnetic properties of multiferroic compounds.Comment: 6 pages, 4 figures-Revised versio

Load-carrying capacity of compressed wall-like RC columns strengthened with FRP

The analytical prediction of the effectiveness of fiber-reinforced polymer (FRP) in the confinement of a rectangular reinforced concrete (RC) column with a high aspect ratio (wall-like) still has an uncertain solution. In this paper, a numerical investigation of the axial response of RC wall-like columns strengthened with FRP systems was developed. Analytical solutions proposed in the literature for the assessment of the axial load capacity were presented and compared with each other and with the available experimental results. Moreover, non-linear finite element analysis was carried out, and the results were discussed, providing a simple model for the assessment of the axial compressive strength of wall-like RC columns strengthened with FRP

Probabilistic assessment of footbridge response to single walkers

Among the load scenarios considered for the serviceability assessment of human-induced footbridge vibration, is that of the transient action of a single pedestrian or a small group of pedestrians. Although such action is stochastic due to the variability of gait parameters, available Codes and Guidelines all assume it is deterministic and equal to that coming from the “worst pedestrian ever” for the given footbridge. This approach is sound from an engineering point of view but does not allow control of the probability of failure. The present work deals with a reliability-based procedure for the serviceability assessment of the footbridge peak characteristic accelerations due to pedestrian induced actions. Based on the results obtained incorporating the effects of the inter-subject variability of gait parameters and of the uncertainties in footbridge dynamic properties, a design response spectrum is proposed for both vertical and lateral vibrations. The proposed procedure lends itself for immediate Code implementation