481 research outputs found

    A combined experimental and computational study of the pressure dependence of the vibrational spectrum of solid picene C_22H_14

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    We present high-quality optical data and density functional perturbation theory calculations for the vibrational spectrum of solid picene (C22_{22}H14_{14}) under pressure up to 8 GPa. First-principles calculations reproduce with a remarkable accuracy the pressure effects on both frequency and intensities of the phonon peaks experimentally observed . Through a detailed analysis of the phonon eigenvectors, We use the projection on molecular eigenmodes to unambiguously fit the experimental spectra, resolving complicated spectral structures, in a system with hundreds of phonon modes. With these projections, we can also quantify the loss of molecular character under pressure. Our results indicate that picene, despite a \sim 20 % compression of the unit cell, remains substantially a molecular solid up to 8 GPa, with phonon modes displaying a smooth and uniform hardening with pressure. The Grueneisen parameter of the 1380 cm^{-1} a_1 Raman peak (γp=0.1\gamma_p=0.1) is much lower than the effective value (γd=0.8\gamma_d=0.8) due to K doping. This is an indication that the phonon softening in K doped samples is mainly due to charge transfer and electron-phonon coupling.Comment: Replaced with final version (PRB

    Vibrational spectrum of solid picene (C_22H_14)

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    Recently, Mitsuhashi et al., have observed superconductivity with transition temperature up to 18 K in potassium doped picene (C22H14), a polycyclic aromatic hydrocarbon compound [Nature 464 (2010) 76]. Theoretical analysis indicate the importance of electron-phonon coupling in the superconducting mechanisms of these systems, with different emphasis on inter- and intra-molecular vibrations, depending on the approximations used. Here we present a combined experimental and ab-initio study of the Raman and infrared spectrum of undoped solid picene, which allows us to unanbiguously assign the vibrational modes. This combined study enables the identification of the modes which couple strongly to electrons and hence can play an important role in the superconducting properties of the doped samples

    Focusing properties of linear undulators

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    This paper investigates the focusing properties of linear magnetic undulators, i.e., devices characterized by weak defocusing properties in the horizontal (wiggling) plane and strongly focusing in the vertical plane. The problem of identifying the conditions that ensure the existence of the electron beam eigenstates in the undulator lattice for a given working point of electron beam energy E_{b} and resonant wavelength λ_{r} is studied. For any given undulator lattice, a bandlike structure is identified defining regions in the (E_{b},λ_{r}) plane where no periodic matching condition can be found, i.e., it is not possible to transport the electron beam so that optical functions are periodic at lattice boundaries. Some specific cases are discussed for the SPARC FEL undulator

    A Framework for Automating Security Assessments with Deductive Reasoning

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    Proper testing of hardware and software infrastructure and applications has become mandatory. To this purpose, security researchers and software companies have released a plethora of domain specific tools, libraries and frameworks that assist human operators (penetration testers, red teamers, bug hunters) in finding and exploiting specific vulnerabilities, and orchestrating the activities of a security assessment. Most tools also require minor reconfigurations in order to operate properly with isomorphic systems, characterized by the same exploitation path even in presence of different configurations. In this paper we present a human-assisted framework that tries to overcome the aforementioned limitations. Our proposal is based on a Prolog-based expert system with facts and deductive rules that allow to infer new facts from existing ones. Rules are bound to actions whose results are fed back into the knowledge base as further facts. In this way, a security assessment is treated like a theorem that has to be proven. We have built an initial prototype and evaluated it in different security assessments of increasing complexity (jeopardy and boot-to-root machines). Our preliminary results show that the proposed approach can address the following challenges; (a) reaching non-standard goals (which would be missed by most tools and frameworks); (b) solving isomorphic systems without the need for reconfiguration; (c) identifying vulnerabilities from chained weaknesses and exposures

    Gender and sex bias in prevention and clinical treatment of women's chronic pain: hypotheses of a curriculum development

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    This discursive paper focuses on undergraduate medical education's role in tackling gender bias in clinical practice, specifically preventing and managing from a non-biomedical perspective chronic pain in women. A preliminary web search of medical schools' curricula was performed to identify programs content related to gender bias in pain management. The web search included 10 universities' websites selected from the top 10 rankings QS Universities Rankings 2022 for medical schools. Additionally, a questionnaire was sent to all deans of the selected academic institutions to explore the curriculum content further. The web search, and the lack of response from the deans, highlighted that relevant curriculum components on gender bias and chronic pain needed to be implemented. Therefore, this paper introduces an innovative curriculum development approach designed by the multi-professional research team to be implemented in medical school programs. This novel educational strategy could also cross-contaminate other healthcare practitioners' university programs and, thus, stimulate an interprofessional debate into fostering inclusiveness and equal opportunities in health

    Local structural studies of Ba1x_{1-x}Kx_xFe2_2As2_2 using atomic pair distribution function analysis

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    Systematic local structural studies of Ba1x_{1-x}Kx_xFe2_2As2_2 system are undertaken at room temperature using atomic pair distribution function (PDF) analysis. The local structure of the Ba1x_{1-x}Kx_xFe2_2As2_2 is found to be well described by the long-range structure extracted from the diffraction experiments, but with anisotropic atomic vibrations of the constituent atoms (U11U_{11} = U22U33U_{22} \ne U_{33}). The crystal unit cell parameters, the FeAs4_4 tetrahedral angle and the pnictogen height above the Fe-plane are seen to show systematic evolution with K doping, underlining the importance of the structural changes, in addition to the charge doping, in determining the properties of Ba1x_{1-x}Kx_xFe2_2As2_2

    Peer support between healthcare workers in hospital and out-of-hospital settings: a scoping review

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    Background and aim: the healthcare workers, mostly in emergency departments, are exposed to emotionally strong situations: this condition often can lead them to operate incorrectly. In the face of the mistake, many of them experience psychological trauma, becoming “second victims” of the event. In this case they can find comfort in dealing with Peers that can help to understand emotions and normalize lived experiences. A scoping review was conducted to clarify the key concepts available in the literature and understand Peer Support characteristics and methods of implementation. Methods: scoping review approach of Joanna Briggs Institute was used. The reviewers analyzed the last twenty-one years of literature and extracted data from relevant studies. Results: 49 articles were relevant. Articles involve mostly physicians and nurses, but all the other healthcare professionals are included. 56% of the articles have been published in the last two years during the Covid 19 pandemic, which revealed the growing need of developing Peer Support programs; the Anglo-Saxon countries are the main geographical area of origin (82%). Peer support emerges as a preclinical psychological support for people involved in tiring situations. It’s based on mutual respect and on voluntary and not prejudicial help. Peers are trained to guide the support relationship. Peer Support can be proposed as one to one/group peer support, or through online platforms. Conclusions: many of the studies affirm that the personnel involved have benefited from the programs available. It is necessary to carry out further research to determine the pre and post intervention benefits. (www.actabiomedica.it)

    Doped Ceria Catalysts for NOx Storage and Reduction

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    The new Euro 7 protocol, proposed by the Commission on 26th October 2022, concerning emissions of leanburn engines, presents a need for further optimisation of existing after-treatment technologies. It reveals a 35% reduction to the NOx emission limit for cars and vans, compared to Euro 6 . A well-known technology employed to reduce NOx to clean emissions in light-duty vehicles is the Lean NOx Trap (LNT). LNTs employ catalysts consisting of PGMs supported on ceria (CeO2) or other mixed oxides. Ceria’s redox property makes it an attractive selection, as well as its ability to store NOx at low temp (<300 ̊C), especially when Pt is present. Storage properties of ceria can be further enhanced by doping. Dopants reportedly allow ceria to function better at low temperature (<300 ̊C), and to reduce the PGM loading required to achieve the same conversion efficiencies. The RE metals Sm, Pr and Nd have been employed as dopants on CeO2 for LNT applications to increase surface oxygen content, oxygen vacancies, defect densities, and cause changes to the Pt-ceria interaction. These structural changes can allow for higher NSC during lean operation and enhanced activation during rich purge. Sm, Pr and Nd doped catalysts (10 wt.%) were synthesised on a range of ceria based catalysts with different Pt loadings (0-1 wt.%). Morphological changes observed through dopant addition has been investigated and related to catalytic performance increases.

    Probiotics in Orthopedics: From Preclinical Studies to Current Applications and Future Perspective

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    In recent years, probiotics have been emerging as an attractive therapeutic strategy for several diseases. In orthopedics, probiotics seem to be a promising supplementation for treatment of osteoporosis, osteoarthritis, muscle loss-related disease, wound and ulcer issues, and prevention of surgical antibiotic prophylaxis side effects. Although probiotics are still not included in guidelines for these conditions, several studies have reported theoretical benefits of their administration. Further high-level clinical trials are necessary to convert research into solid clinical practice. However, probiotics represent a cost-effective future perspective and may play a role in association with traditional orthopedic therapies

    The safety of care focused on patient identity: an observational study

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    BACKGROUND AND AIM: Healthcare organizations, in order to reduce errors and extend the number of safe practices, are looking for possible solutions to enhance the clients' health quality care and trying to spread the culture of safety healthcare. Although in the literature the field of research "patient safety" is very debated, there are few empirical studies that investigate about the strategies undertaken by nursing students for the patients identification process during their care pathway. The aim of this study is to investigate the knowledge of the Ministerial Recommendation No. 3/2008 among nursing students, a specific Italian directive that aims to guarantee the safety of cares. METHODS: A four-weeks single-center observational study was conducted, involving a convenient sample of 112 students of the 2nd and 3rd&nbsp; year of the Nursing Course Degree of the University of Parma. The survey was conducted using an ad-hoc questionnaire. RESULTS: The use of the identification wristband is considered one of the most important strategy to make sure the patient identification; unfortunately it is in practice used just in few occasions and only when performed specific procedures; it is furthermore noted that patients are not enough informed about the use and finalities of the identification wristband. CONCLUSIONS: Considering the importance of the patient identification process to guarantee the &nbsp;safety of cares, the results produced, suggest that this investigation field deserves further insights in order to collect more substantial data and expand knowledge on the specific subject, so as to fill&nbsp; knowledge gaps and sensitize nursing students to the correct use of the identification wristband
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