Variational principles of micromagnetics revisited

We revisit the basic variational formulation of the minimization problem associated with the micromagnetic energy, with an emphasis on the treatment of the stray field contribution to the energy, which is intrinsically non-local. Under minimal assumptions, we establish three distinct variational principles for the stray field energy: a minimax principle involving magnetic scalar potential and two minimization principles involving magnetic vector potential. We then apply our formulations to the dimension reduction problem for thin ferromagnetic shells of arbitrary shapes

THE PATIENT IN THE OPERATING ROOM: CONSIDERATION AT SEVEN YEARS FROM WORLD HEALTH ORGANIZATION GUIDELINES PUBLICATION.

Modern surgery is burdened by a huge amount of patient to be treated and an increasingly complex number of procedures which request planned action and shared behaviours, aimed to prevent perioperative accidents and favour good surgical outcomes. Surgical and anaesthetic safety has improved significantly in last few decades. However, the operating room environment continues to have significant safety risks for patients as well as the health care providers who work there. Adverse events may result from problems in practice, products, procedures or systems. The worldwide incidence of surgical site infection, one of the most important and frequent post-operative complication, ranges from 3% to 16%, with a mortality rate ranging from 0.4% to 0.8%; in these studies, about 50% of cases were considered preventable (1-9). Patients safety improvements demand a complex system-wide effort, involving a wide range of actions in performance improvement, environmental safety and risk management, including infection control, safe use of medicines, equipment safety, safe clinical practice and safe environment of care. Just as public health interventions and educational projects have dramatically improved maternal and neonatal survival, analogous efforts might improve surgical safety and quality of care (10). According to these objectives, the World Health Organization (WHO) has published and diffused the international “Guidelines for Safe Surgery” (11). The guidelines have the clear proposal to 61ameliorate the safety of surgical interventions; they define and promote recommendation and safety standards suitable for the different Countries and operative settings, suggesting a new deal in managing pre-operative, intra-operative and post-operative processes. On the base of these recommendations, the WHO has also developed a checklist for the safety in the operating room, in order to prevent avoidable adverse events, thus minimizing unnecessary loss of life and serious complications. The results raised from a multicentre study carried out in eight different Countries, demonstrating the effectiveness of the WHO checklist in terms of better patient safety, reduction of deaths and post-operative complications (12). The objectives of this international effort are resumable as follow: 1. the patient must be correctly positioned on the surgical bed and prepared; 2. the surgery team must operate on the correct patient at the correct site; 3. blood loss and risk for surgical site infection must be minimized; 4. inadvertent retention of instruments and sponges in surgical site must be prevented; 5. during surgery, anaesthesiologists must prevent harm from the administration of anaesthetics, while protecting the patient from pain; 6. anaesthesiologists must manage patient’s airways and respiratory function, in order to avoid life-threatening complications; 7. the team should consider patient’s allergies or intolerances in order to prevent an allergic or adverse drug reaction; 8. at the end of intervention, the surgical team must secure and accurately identify all surgical specimens, while the anaesthesiologists will guarantee a correct patient awakening; 9. all the members of the team will effectively communicate and exchange critical information for the safe conduct of the operation; 10. post-operative thromboembolism must be prevented adopting the right measures; 11. each member of the team is responsible for his own clinical documentation; 12. hospitals and public health systems will establish routine surveillance of surgical capacity, volume and results. On March 2013, the American Agency for Health Research and Quality (AHRQ) published the Making Health Care Safer II report, which confirmed the effectiveness of WHO checklist and considered it as one of the 10 strongest recommended practices health care organizations should immediately apply to improve patient safety (13). After the first launch of the WHO checklist, the American Veteran Health Administration observed a constant reduction of patient mortality (0.5/1000 surgeries/4 months); in Holland, compliance to the new guidelines raised from 12% of the first 4 months to the 60%, observed at the end of the second year after publication. This means that «The checklist only works if you use it» (14). The checklist does not reduces itself patient complications, but only the application of all the provided items could help to do so. The checklist should be understood not merely as a list of items to be checked off, but as an instrument for the improvement of communication, teamwork, and safety culture in the operating room, and it should be accordingly implemented. To reach the expected results it needs time, the time to let surgical team to learn and involve (gradually) all the interested units of a determined hospital or the hospitals of a specific geographic area. Agreeing with Bosk and colleagues (15), using an electronic recording format within the standard mandatory strategy facilitates apparent compliance and the use of the safety checklist as a tick box exercise. It seems that the main trick to improving safety is a strategy leading to positive attitudes on the part of the health professionals involved, involving a far more complex adaptive process than merely mandating the use of a checklist

Time dependent Markovian master equation beyond the adiabatic limit

We develop a Markovian master equation that models the evolution of systems subject to arbitrary driving and control fields. Our approach combines time rescaling and weak-coupling limits for the system-environment interaction with a secular approximation. The derivation makes use of the adiabatic time evolution operator in a manner that allows for the efficient description of strong driving, while recovering the adiabatic master equation in the appropriate limit. To illustrate the effectiveness of our approach, we apply it to the paradigmatic case of a two-level (qubit) system subjected to a form of periodic driving that remains unsolvable using a Floquet representation. We demonstrate the reliability and broad scope of our approach by benchmarking the solutions of the derived reduced time evolution against numerically exact simulations using tensor networks. Our results provide rigorous conditions that must be satisfied by phenomenological master equations for driven systems that do not rely on first principles derivations.Comment: 20+8 pages, 5 figures. Comments are welcom

Laboratory Test Campaign Aimed at the Analysis of an Uncommon Wear Phenomenon in a Marble Quarry

The use of ornamental stones has a historical value that makes them strategically precious in Italy; marble can offer high performance in architectural applications, even though the variability of the rock mass requires detailed studies to optimize the exploitation techniques and reduce waste. Italy is world famous for its marble, which is extracted mainly through chainsaw cutting machines, which are currently used intensively due to their high‐safety working conditions compared to alternative techniques and for their great versatility, especially in underground applications. Although this cutting technique is well‐rooted, an uncommon problem of tool wear was found in the quarry under study, which strongly affected productivity. A series of laboratory test were carried out to estimate the wear potential of the rock and the suitability of the tools. The Cerchar abrasivity test highlighted a mean wear potential for the marble of 2.77, while microhardness outcomes pointed out the presence of quartz veins in the tested material (values over 10000 MPa). Finally, additives typically used in the conditioning process of EPB machines in tunneling were tested with the purpose of reducing the extent of wear. A reduction of about 50% in the wear (in terms of weight lost) was obtained for a moisture content of 9%

Artefacts: a multi-voiced collection of paraphernalia, documentation and reflection on the space and words for dancers work-week

Artefacts is a multi-voiced collection of paraphernalia, documentation and reflection relating to a week-long event (July 2015) that revolved around the work of dancers and poets Julyen Hamilton (Spain) and Billie Hanne (Belgium). Hosted by Chisenhale Dance Space, London, and curated by dance-artist Antonio de la Fe and artist/scholar Robert Vesty, the Space and Words for Dancers event consisted of a six-day workshop for 25 dancers led by Hamilton and Hanne that focused on the use of space and words in performance; two solo performances by Hamilton (Play) and Hanne (Deep Brown Sea); an Evening Talk event with Hamilton and Hanne talking in-depth about their work and the making of poetry and dance; as well as an open-to-the-public Discussion Day that used Open Space Technology (OST) as an organizing tool to discuss the question ‘What skills are required of the dancer and poet to produce poetry and dance in performance?’. Artefacts is a collaboration with graphic designer Tomas Di Giovanni and includes Billie’s Outline, a rationale for bringing words and dance together in the workshop, written by Hanne; poetry by Hamilton and Hanne composed especially for this Words and Dance issue of Choreographic Practices; programme notes from Play and Deep Brown Sea; a reflective piece by Antonio de la Fe on the nature of work for the dance artist as performer entitled That You Took the Workshop Doesn’t Mean You Have Done the Work; a photo-essay by resident photographer Maria Andrews; extracts from the transcript of Evening Talk collated around the headings On Poetry and Dance, On Space, On Making Pieces, On Repeating Pieces and On How it Works; and finally, a nod to the discussion day. Overall, the aim of Artefacts is to pull together some coordinates of the different and multifarious strands of activity that went into and came out of the Space and Words for Dancers work-week, which inspired this special Words and Dance edition of Choreographic Practices, but to do so in a way that might begin to perform and applaud the aesthetic quality of the work with space and words

Breaking Symmetry Rules Enhance the Options for Stereoselective Propene Polymerization Catalysis

An example of breaking "Ewen's symmetry rule" for olefin catalysis polymerization is proposed by DFT calculations. Catalyst precursors with Cs symmetry are suggested to promote the isotactic propene polymerization by a modification of the active site geometry obtained via coordination with AlH-alkyl species in solution. The origin of stereocontrol in olefin polymerization is due to a dual mechanism dictated by the chiral catalyst. These findings may expand the toolbox for promoting stereoselective olefin polymerization by transition metal catalysts

Partition Functions of Non-Abelian Quantum Hall States

Partition functions of edge excitations are obtained for non-Abelian Hall states in the second Landau level, such as the anti-Read-Rezayi state, the Bonderson-Slingerland hierarchy and the Wen non-Abelian fluid, as well as for the non-Abelian spin-singlet state. The derivation is straightforward and unique starting from the non-Abelian conformal field theory data and solving the modular invariance conditions. The partition functions provide a complete account of the excitation spectrum and are used to describe experiments of Coulomb blockade and thermopower.Comment: 42 pages, 3 figures; published version; minor corrections to sect. 4.