An anomalous alloy: Y_x Si_{1-x}

We study via density functional-based molecular dynamics the structural and dynamical properties of the rare earth silicon amorphous alloy Y_xSi_{1-x} for x=0.093 and x=0.156. The Si network forms cavities in which a Y^{3+} cation is entrapped. Its electrons are transferred to the Si network and are located in the dangling bonds of the Si atoms that line the Y cavities. This leads to the presence of low coordinated Si atoms that can be described as monovalent or divalent anions. For x=0.156, the cavities touch each other and share Si atoms that have two dangling bonds. The vibrational spectrum is similar to that of amorphous Si. However, doping induces a shoulder at 70 cm^{-1} and a pronounced peak at 180 cm^{-1} due to low coordinated Si.Comment: 4 pages, 4 figure

Incidence rate and risk factors for vaginal vault prolapse repair after hysterectomy

Our objective was to estimate the incidence and identify the risk factors for vaginal vault prolapse repair after hysterectomy. We conducted a case control study among 6,214 women who underwent hysterectomy from 1982 to 2002. Cases (n = 32) were women who required vaginal vault suspension following the hysterectomy through December 2005. Controls (n = 236) were women, randomly selected from the same cohort, who did not require pelvic organ prolapse surgery. The incidence of vaginal vault prolapse repair was 0.36 per 1,000 women-years. The cumulative incidence was 0.5%. Risk factors included preoperative prolapse (odds ratio (OR) 6.6; 95% confidence interval (CI) 1.5-28.4) and sexual activity (OR 1.3; 95% CI 1.0-1.5). Vaginal hysterectomy was not a risk factor when preoperative prolapse was taken into account (OR 0.9; 95% CI 0.5-1.8).Vaginal vault prolapse repair after hysterectomy is an infrequent event and is due to preexisting weakness of pelvic tissue

Efficacy and safety of trabeculectomy vs nonpenetrating surgical procedures: a systematic review and meta-analysis

To date, only a few studies have directly compared nonpenetrating surgery (NPS) and trabeculectomy (TE). Therefore, there is no strong evidence as to which surgical technique leads to the best results in terms of ocular hypotensive effect and safety

Molecular dynamics study of the fragmentation of silicon doped fullerenes

Tight binding molecular dynamics simulations, with a non orthogonal basis set, are performed to study the fragmentation of carbon fullerenes doped with up to six silicon atoms. Both substitutional and adsorbed cases are considered. The fragmentation process is simulated starting from the equilibrium configuration in each case and imposing a high initial temperature to the atoms. Kinetic energy quickly converts into potential energy, so that the system oscillates for some picoseconds and eventually breaks up. The most probable first event for substituted fullerenes is the ejection of a C2 molecule, another very frequent event being that one Si atom goes to an adsorbed position. Adsorbed Si clusters tend to desorb as a whole when they have four or more atoms, while the smaller ones tend to dissociate and sometimes interchange positions with the C atoms. These results are compared with experimental information from mass abundance spectroscopy and the products of photofragmentation.Comment: Seven two-column pages, six postscript figures. To be published in Physical Review

El Centro Médico Psicopedagogico Salesiano

Esta obra es la reedición de la tesis doctoral de Emilio Gambirasio sdb (1922-1991) la cual propone los principios conceptuales, metodológicos y operativos de un centro médico psicopedagógico salesiano. No se trata de una investigación abstracta ya que recoge la experiencia y la reflexión del autor sobre su trabajo concreto y creativo al frente del Centro Psicológico Salesiano desde sus años fundacionales. Ello le ha permitido identificar las motivaciones, los aspectos organizacionales y las dimensiones de las actividades diagnósticas y terapéuticas de un Centro que ha dejado profunda huella en los departamentos de orientación y bienestar estudiantil de las unidades educativas, principalmente de Quito. El libro ha sido concebido por el Dr. Patricio Bermúdez, profesor de la Carrera de Psicología y discípulo del autor, para garantizar la reflexión y memoria de las fuentes que inspiran el funcionamiento actual del Centro. A la vez, se constituye en un homenaje al fundador de una iniciativa vigente que ha persistido en el tiempo

Organizational Learning in Healthcare Contexts after COVID-19: A Study of 10 Intensive Care Units in Central and Northern Italy through Framework Analysis

The rapid spread of the SARS-CoV-2 virus has forced healthcare organizations to change their organization, introducing new ways of working, relating, communicating, and managing to cope with the growing number of hospitalized patients. Starting from the analysis of the narratives of healthcare workers who served in the intensive care units of 10 hospitals in Central and Northern Italy, this contribution intends to highlight elements present during the pandemic period within the investigated structures, which are considered factors that can influence the birth of organizational learning. Specifically, the data collected through interviews and focus groups were analyzed using the framework analysis method of Ritchie and Spencer. The conducted study made it possible to identify and highlight factors related to aspects of communication, relationships, context, and organization that positively influenced the management of the health emergency, favoring the improvement of the structure. It is believed that the identification of these factors by healthcare organizations can represent a valuable opportunity to rethink themselves, thus becoming a source of learning

Large strain computational modeling of high strain rate phenomena in perforating gun devices by Lagrangian/Eulerian FEM simulations

The present doctoral thesis deals with the study and the analysis of large strain and high strain rate behavior of materials and components. Theoretical, experimental and computational aspects are taken into consideration. Particular reference is made to the modeling of metallic materials, although other kinds of materials are considered as well. The work may be divided into three main parts. The first part of the work consists in a critical review of the constitutive modeling of materials subjected to large strains and high to very high strain rates. Specific attention is paid to the opportunity of adopting so-called strength models and equations of state. Damage and failure modeling is discussed as well. In this part, specific interest is addressed to reviewing the so-called Johnson-Cook strength model, by critically highlighting its positive and negative aspects. One of the main tackled issue consists in a reasoned assessment of the various procedures adoptable in order to calibrate the parameters of the model. This phase is enriched and clarified by applying different calibration strategies to a real case, i.e. the evaluation of the model parameters for a structural steel. The consequences determined by each calibration approach are then carefully evaluated and compared. The second part of the work aims at introducing a new strength model, that consists in a generalization of the Johnson-Cook model. The motivations for the introduction of this model are first exposed and discussed. The features of the new strength model are then described. Afterwards, the various procedures adoptable for the determination of the material parameters are presented. The new strength model is then applied to a real case, i.e. a structural steel as above, and the results are compared to those obtained from the original Johnson-Cook model. Comparing to that, the obtained outcomes show that the new model displays a better capacity in reproducing experimental data. Results are discussed and commented. The third and final part of the work deals with an application of the studied topics to a real industrial case of interest. A device called perforating gun is analyzed in its structural problematics and critical aspects. This challenging application involves the modeling of several typologies of material, large strains, very high strain rate phenomena, high temperatures, explosions, hypervelocity impacts, damage, fracture and phase changes. In this regard, computational applications of the studied theories are presented and their outcomes are assessed and discussed. Several finite element techniques are considered. In particular, tridimensional Eulerian simulations are presented. The obtained results appear to be very promising in terms of the possibilities of a fruitful use in the design process of the device, in particular in order to achieve an optimization of its key features

What Makes Me Stay Here? An Action Research Approach to Organisational Change

This article takes a qualitative approach to understanding the meaning of the good life in a situated organisational context, addressing the possibility of staying at work as a good enough place, even though it is facing critical events (turnover, mass resignations, and mergers and acquisitions). The paper presents a case study of a tax and legal firm that was formed in 2020 from the merger of two accounting firms and that is having difficulties attracting and retaining experienced talent. The article aims to explore a concrete organisational case in which people are grappling with the decision to remain with the firm (legacy and persistence) or leave in search of new professional opportunities (innovation and change). Epistemological and methodological implications are highlighted, focusing on the research object as a heterotopic text in which various languages, voices and practices are diffractionally assembled Deleuze and Guattari 1987), interweaving various discourses and practices (Cunliffe and Locke 2020)

Ecomusicology and the potential of music and sound for environmental education

Ecomusicology is an interdisciplinary field drawing together scholars from sciences and humanities who share a research interest in the overlapping of music, culture, and nature. Human and non-human animals constantly rely on sonic signals to relate with other animals and the environment. Considering this auditory connection, and the contribution that ecocritical music and music about places may have in nurturing a sentiment of environmental stewardship, I propose an applied environmental education methodology that relies on participatory music making and critical listening to foster environmental awareness