Electronic excitations and the tunneling spectra of metallic nanograins

Tunneling-induced electronic excitations in a metallic nanograin are classified in terms of {\em generations}: subspaces of excitations containing a specific number of electron-hole pairs. This yields a hierarchy of populated excited states of the nanograin that strongly depends on (a) the available electronic energy levels; and (b) the ratio between the electronic relaxation rate within the nano-grain and the bottleneck rate for tunneling transitions. To study the response of the electronic energy level structure of the nanograin to the excitations, and its signature in the tunneling spectrum, we propose a microscopic mean-field theory. Two main features emerge when considering an Al nanograin coated with Al oxide: (i) The electronic energy response fluctuates strongly in the presence of disorder, from level to level and excitation to excitation. Such fluctuations produce a dramatic sample dependence of the tunneling spectra. On the other hand, for excitations that are energetically accessible at low applied bias voltages, the magnitude of the response, reflected in the renormalization of the single-electron energy levels, is smaller than the average spacing between energy levels. (ii) If the tunneling and electronic relaxation time scales are such as to admit a significant non-equilibrium population of the excited nanoparticle states, it should be possible to realize much higher spectral densities of resonances than have been observed to date in such devices. These resonances arise from tunneling into ground-state and excited electronic energy levels, as well as from charge fluctuations present during tunneling.Comment: Submitted to the Physical Review

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Carrier Capture Time In T-shaped Semiconductor Quantum Wires

We investigate the capture time from quasi-two-dimensional (2D) electrons to quasi-one-dimensional (1D) electrons in T-shaped semiconductor quantum wires. Two processes are considered: longitudinal-optical-(LO)-phonon emission and quasi-elastic acoustical-phonon scattering. The quasi-1D ground state is a shallow bound state and is separated by less than one LO-phonon from the quasi-2D continuum. This enhances the LO-phonon emission process which largely dominates the capture process. The effects of the modulation of the density probability of the quasi-2D continuum lead only to a weak dependence of the capture time on the structure parameters. © 1998 Elsevier Science B.V. All rights reserved.21-4983986Wegscheider, W., Pfeiffer, L.N., Dignam, M.M., Pinczuk, A., West, K.W., McCall, S.L., Hull, R., (1993) Phys. Rev. Lett., 71, p. 4071Ryan, J.F., Maciel, A.C., Kiener, C., Rota, L., Freyland, J.M., Turner, K., Marti, U., Reinhart, F.K., (1996) Proc. 23rd Int. Conf. on Semiconductor Physics, p. 1181. , BerlinCotta, M.A., Hamm, R.A., Chu, S.N.G., Hull, R., Harriot, L.R., Panish, M.B., Temkin, H., (1993) Phys. Rev. Lett., 70, p. 4106Marquezini, M.V., Brasil, M.J.S.P., Cotta, M.A., Brum, J.A., Bernussi, A.A., (1996) Phys. Rev. B, 53, pp. R16156Brum, J.A., Bastard, G., (1985) Phys. Rev. B, 33, p. 1420Blom, P.W.M., Smit, C., Haverkort, J.E.M., Wolter, J.H., (1993) Phys. Rev. B, 47, p. 2072Morris, D., Deveaud, B., Regreny, A., Auvray, P., (1993) Phys. Rev. B, 47, p. 6819Barros, M.R.X., Becker, P.C., Morris, D., Deveaud, B., Regreny, A., Beisser, F., (1993) Phys. Rev. B, 47, p. 10951Bastard, G., Brum, J.A., Ferreira, R., (1991) Solid State Physics, 44, p. 229. , H. Ehrenreich, D. Turnbull (Eds.), Academic Press, New YorkLangbein, W., Gislason, H., Hvam, J.M., (1996) Phys. Rev. B, 54, p. 14595Bastard, G., (1984) Phys. Rev. B, 30, p. 3547Rücker, H., Molinari, E., Lugli, P., (1991) Phys. Rev. B, 44, p. 3463Thilagam, A., Singh, J., (1993) J. Lumin., 55, p. 11Kusano, J.-I., Segawa, Y., Aoyagi, Y., Namba, S., Okamoto, H., (1989) Phys. Rev. B, 40, p. 1685Damen, T.C., Oberli, D.Y., Chemla, D.S., Cunningham, J.E., Kuo, J.M., (1990) J. Lumin., 45, p. 181(1990) Phys. Rev. B, 42, p. 7434Kumar, R., Vergurlekar, A.S., Prablhu, S.S., Shah, J., Pfeiffer, L.N., (1996) Phys. Rev. B, 54, p. 489

Adaptación transcultural al castellano del sistema de evaluación del equilibrio (Bestest) en adultos mayores

Introduction. The risk of falls in older adults increases because of the decrease in strength, flexibility, balance and sensory changes affecting functionality and quality of life. For this reason, an integral system of evaluation of equilibrium is necessary, for preventive purposes or for early therapeutic interventions. Aim. To present the results of the transcultural translation and adaptation process of the Balance Evaluation Systems Test (BESTest) to Spanish language. Subjects and methods. The original version of the BESTest was translated into Spanish, following the process of retro-traduction and cultural adaptation considering the semantic, idiomatic, conceptual and experiential equivalences. Subsequently the version was reviewed by a panel of experts qualifying clarity, coherence, relevance and sufficiency. The pilot test included 32 adults between 50 and 80 years old. Results. It was possible to carry out the complete translation of the instrument, the instructions for the subject and for the evaluator. Most items of the test reached the maximum score of 4.0 (100%), nine items achieved an average score of 3.9 (99%), one item got an average score of 3.8 (95%) and two items achieved an average score of 3.7 (92.5%). Conclusions. With this study the Spanish speakers community has a pertinent sufficient, coherent and clear instrument in order to identify the control postural system altered to focus treatment and to get better functional outcomes from balance evaluation in older adults. © 2018 Revista de Neurología

The brand likeability scale: an exploratory study of likeability in firm-level brands

We develop a new measurement scale to assess consumers’ brand likeability in firm-level brands. We present brand likeability as a multidimensional construct. In the context of service experience purchases, we find that increased likeability in brands results in: (1) greater amount of positive association; (2) increased interaction interest; (3) more personified quality; and (4) increased brand contentment. The four-dimensional multiple-item scale demonstrates good psychometric properties, showing strong evidence of reliability as well as convergent, discriminant and nomological validity. Our findings reveal that brand likeability is positively associated with satisfaction and positive word of mouth. The scale extends existing branding research, providing brand managers with a metric so that likeability can be managed strategically. It addresses the need for firms to act more likeably in an interaction-dominated economy. Focusing on likeability acts as a differentiator and encourages likeable brand personality traits. We present theoretical implications and future research directions on the holistic brand likeability concept