The slopes of sub-barrier heavy-ion fusion excitation functions shed light on the dynamics of quantum tunnelling.

Quantum tunnelling plays a crucial role in heavy-ion fusion reactions at sub-barrier energies, especially in the context of nuclear physics and astrophysics. The nuclear structure of the colliding nuclei and nucleon transfer processes represent intrinsic degrees of freedom. They are coupled to the relative ion motion and, in general, increase the probability of tunnelling. The influence of couplings to nucleon transfer channels relatively to inelastic excitations, on heavy-ion fusion cross sections, is one of the still open problems in this field. We present a new analysis of several systems, based on the combined observation of the energy-weighted excitation functions E σ in relation to their first energy derivatives d ( E σ ) / d E . The relation between d ( E σ ) / d E and E σ removes the basic differences due to the varying Coulomb barrier when comparing different systems. We show that, depending on the nuclear structure and/or the presence of strong transfer channels, this representation reveals characteristic features below the barrier. The possible presence of cross section oscillations makes this analysis less clear for light- or medium-light systems.

A management perspective on resilience in healthcare: a framework and avenues for future research.

Recent major health shocks, such as the 2014-16 Ebola, the Zika outbreak, and, last but not least, the COVID-19 pandemic, have strongly contributed to drawing attention to the issue of resilience in the healthcare domain. Nevertheless, the scientific literature appears fragmented, creating difficulties in developing incremental research in this relevant managerial field.To fill this gap, this systematic literature review aims to provide a clear state of the art of the literature dealing with resilience in healthcare. Specifically, from the analysis of the theoretical articles and reviews, the key dimensions of resilience are identified, and a novel classification framework is proposed. The classification framework is then used to systematize extant empirical contributions. Two main dimensions of resilience are identified: the approach to resilience (reactive vs. proactive) and the type of crisis to deal with (acute shocks vs. chronic stressors). Four main streams of research are thus identified: (i) proactive approaches to acute shocks; (ii) proactive approaches to chronic stressors; (iii) reactive approaches to acute shocks; and (iv) reactive approaches to chronic stressors. These are scrutinised considering three additional dimensions: the level of analysis, the resources to nurture resilience, and the country context. The classification framework and the associated mapping contribute to systematising the fragmented literature on resilience in healthcare, providing a clear picture of the state of the art in this field and drawing a research agenda that opens interesting paths for future research.

Neutron pair transfer in (60)Ni+(116)Sn far below the Coulomb barrier.

An excitation function of one- and two-neutron transfer channels for the ^{60}Ni+^{116}Sn system has been measured with the magnetic spectrometer PRISMA in a wide energy range, from the Coulomb barrier to far below it. The experimental transfer probabilities are well reproduced, for the first time with heavy ions, in absolute values and in slope by microscopic calculations which incorporate nucleon-nucleon pairing correlations.

Fusion hindrance for a positive-q-value system (24)Mg+(30)Si.

Measurements of the excitation function for the fusion of (24)Mg+(30)Si (Q=17.89 MeV)have been extended toward lower energies with respect to previous experimental data. The S-factor maximum observed in this large, positive-Q-value system is the most pronounced among such systems studied thus far. The significance and the systematics of an S-factor maximum in systems with positive fusion Q values are discussed. This result would strongly impact the extrapolated cross sections and reaction rates in the carbon and oxygen burnings and, thus, the study of the history of stellar evolution.

Exploring the effect of the Cardinium endosymbiont on spiders.

Spiders have recently emerged as important diversity hot spots for endosymbiotic bacteria, but the consequences of these symbiotic interactions are largely unknown. In this article, we examined the evolutionary history and effect of the intracellular bacterium Cardinium hertigii in the marbled cellar spider Holocnemus pluchei. We showed that Cardinium infection is primarily transmitted in spider populations maternally via egg cytoplasm, with 100% of the progeny from infected mothers being also infected. Examination of a co-inherited marker, mitochondrial DNA (mtDNA), revealed that Cardinium infection is associated with a wide diversity of mtDNA haplotypes, showing that the interaction between Cardinium and H. pluchei has a long-term evolutionary dimension and that horizontal transmission among individuals could also occur. Although Cardinium is well known to exert sex ratio distortion or cytoplasmic incompatibility in various arthropod hosts, we show, however, that Cardinium does not interact with the reproductive biology of H. pluchei. A field survey shows a clear geographical structuring of Cardinium infection, with a marked gradual variation of infection frequencies from ca. 0.80 to 0. We discuss different mechanistic and evolutionary explanations for these results as well as their consequences for spider phenotypes. Notably, we suggest that Cardinium can either behave as a neutral cytoplasmic element within H. pluchei or exhibit a context-dependent effect, depending on the environmental conditions.

Lifetime measurements of the neutron-rich N = 30 isotones 50Ca and 51Sc: orbital dependence of effective charges in the fp shell.

The lifetimes of the first excited states of the N = 30 isotones (50)Ca and (51)Sc have been determined using the Recoil Distance Doppler Shift method in combination with the CLARA-PRISMA spectrometers. This is the first time such a method is applied to measure lifetimes of neutron-rich nuclei populated via a multinucleon transfer reaction. This extends the lifetime knowledge beyond the f_{7/2} shell closure and allows us to derive the effective proton and neutron charges in the fp shell near the doubly magic nucleus (48)Ca, using large-scale, shell-model calculations. These results indicate an orbital dependence of the core polarization along the fp shell.

Characterization of a mammographic system based on single photon counting pixel arrays coupled to GaAs x-ray detectors.

The authors report on the imaging capabilities of a mammographic system demonstrator based on GaAs pixel detectors operating in single photon counting (SPC) mode. The system imaging performances have been assessed by means of the transfer functions: The modulation transfer function (MTF), the normalized noise power spectrum, and the detective quantum efficiency (DQE) have been measured following the guidelines of the IEC 62220-1-2 protocol. The transfer function analysis has shown the high spatial resolution capabilities of the GaAs detectors. The MTF calculated at the Nyquist frequency (2.94 cycles/mm) is indeed 60%. The DQE, measured with a standard mammographic beam setup (Mo/Mo, 28 kVp, with 4 mm Al added filter) and calculated at zero frequency, is 46%. Aiming to further improve the system's image quality, the authors investigate the DQE limiting factors and show that they are mainly related to system engineering. For example, the authors show that optimization of the image equalization procedure increases the DQE(0) up to 74%, which is better than the DQE(0) of most clinical mammographic systems. The authors show how the high detection efficiency of GaAs detectors and the noise discrimination associated with the SPC technology allow optimizing the image quality in mammography. In conclusion, the authors propose technological solutions to exploit to the utmost the potentiality of GaAs detectors coupled to SPC electronics.

A pixel detector-based single photon-counting system as fast spectrometer for diagnostic X-ray beams.

Recent advances in semiconductor pixel detectors and read-out electronics allowed to build the first prototypes of single photon-counting imaging systems that represent the last frontier of digital radiography. Among the advantages with respect to commercially available digital imaging systems, there are direct conversion of photon energy into electrical charge and the effective rejection of electronic noise by means of a thresholding process. These features allow the photon-counting systems to achieve high imaging performances in terms of spatial and contrast resolution. Moreover, the now available deep integration techniques allow the reduction of the pixel size and the improvement of the functionality of the single cell and the read-out speed so as to cope with the high fluxes found in diagnostic radiology. In particular, the single photon-counting system presented in this paper is based on a 300-microm thick silicon pixel detector bump-bonded to the Medipix2 read-out chip to form an assembly of 256 x 256 square pixels at a pitch of 55 microm. Each cell comprises a low-noise preamplifier, two pulse height discriminators and a 14-bit counter. The maximum counting rate per pixel is 1 MHz. The chip can operate in two modalities: it records the events with energy above a threshold (single mode) or between two energy thresholds (window mode). Exploiting this latter feature, a possible application of such a system as a fast spectrometer is presented to study the energy spectrum of diagnostic beams produced by X-ray tubes.

Nurses' knowledge and application of evidence-based guidelines for preventing ventilator-associated pneumonia.

AIM: The aim of the study was to evaluate the nurses' knowledge and to highlight the causes that hinder guidelines implementation. EXPERIMENTAL DESIGN: descriptive study. SETTING AND PARTICIPANTS: 106 nurses working in the ICUs of a major Italian hospital of national importance. INTERVENTION: administration of a questionnaire listing 21 non-pharmacological strategies considered the most useful in the literature. RESULTS: Eighty-four nurses responded to the questionnaire. Only 19 (22.6%) declared that their knowledge of ventilation associated pneumonia (VAP) and the strategies used to prevent it were satisfactory, whereas 46 (54.8%) declared that they were poorly informed; 68 nurses (80.9%) said that they applied one or more strategies, and 15 (17.9%) that they applied none. The reasons given for not applying the strategies were: method not foreseen in Department protocols (31.5%), lack of the necessary resources (14.3%), disagreement with the method (3.2%), high costs (2.6%), the possibility of causing discomfort (1%) or side effects (0.6%). CONCLUSIONS: In our experience, VAP preventive strategies are widely applied by nurses, but not in a responsible and informed manner. It is important to ensure that nurses receive continuous training and are involved in drawing up and updating Departmental protocols and guidelines for care and behaviour.

Energetics of midvelocity emissions in peripheral heavy ion collisions at Fermi energies.

Peripheral and semiperipheral collisions have been studied in the system 93Nb+93Nb at 38A MeV. The evaporative and midvelocity components of the light charged particle and intermediate mass fragment emissions have been carefully disentangled. In this way it was possible to obtain the average amount not only of charge and mass, but also of energy, pertaining to the midvelocity emission, as a function of an impact parameter estimator. This emission has a very important role in the overall balance of the reaction, as it accounts for a large fraction of the emitted mass and for more than half of the dissipated energy. As such, it may give precious clues on the microscopic mechanism of energy transport from the interaction zone toward the target and projectile remnants.

Regional filter heparinization for continuous veno-venous hemofiltration in liver transplant recipients.

AIM: To study safety, clinical and operative feasibility of continuous veno-venous hemofiltration (CVVH) with anticoagulation only of the filter in patients at risk for bleeding. METHODS: This prospective, comparative, non randomised study was completed at an intensive care unit of a teaching NHS hospital. Sixteen liver transplant (LT) recipients with acute renal failure needing CVVH were treated with a regional anticoagulation protocol (heparin and protamine were administered respectively pre- and post-filter) and compared to 11 critically ill subjects who received a standard low-heparin treatment. Activated coagulation time (ACT) monitoring was used to adjust anticoagulation and heparin neutralization. RESULTS: Mean circuit life was 35.8+/-13.6 hours (95% CI 28.5-43.1) in patients receiving regional anticoagulation and 34.4+/-14 hours in controls (95% CI 25.5-43.3; p=0.7). Fourty-eight circuits (47.5% of the total) in the heparin-protamine group had a life-span longer than 30 hours and other 22 (21.7%) were changed intentionally after 24 hours of use in absence of clots. None of the patients in both the studied groups had bleeding or hemodynamic complications and their azotemic control was always satisfactory. CONCLUSION: In LT recipients, regional anticoagulation can achieve a circuits life-span comparable to that from systemic anticoagulation with satisfactory safety and simplicity of use.

Intermediate mass fragment emission pattern in peripheral heavy-ion collisions at Fermi energies.

The emission pattern in the v(perp)-v(par) plane of intermediate mass fragments with Z = 3--7 (IMF) has been studied in the collision 116Sn+ 93Nb at 29.5A MeV as a function of the total kinetic energy loss of the reaction. This pattern shows that for peripheral reactions most IMF's are emitted at velocities intermediate between those of the projectile- and target-like products. Coulomb trajectory calculations show that these IMF's are produced in the interaction zone in a short time interval at the end of the target-projectile interaction.

The hospital as an enterprise: management strategies.

After introducing the context in which health systems exist in developing as well as in industrialized countries, the author describes the role that hospitals are expected to play as 'enterprises'. The rationale behind such a role is explored and the experience so far available discussed. Evidence from several developing countries suggests caution and trends to discourage radical and indiscriminate introduction of market-oriented reforms, which international donors seem to be spearheading in Africa's health systems. It is likely however, that a limited, gradual introduction of selected elements of these reforms (such as some aspects of contracting out, managerial decentralization, the split between purchasing and providing functions) may find its place and eventually have a positive impact on the performance of the health systems. But 'mystique of markets' must not be allowed to deprive public hospitals of the sense of social utility and of the caring ethos which are essential requisites of a meaningful and effective public health system.