Passivity-based control (PBC) is a well-established technique that has shown to be very powerful to design robust controllers for physical systems described by Euler-Lagrange (EL) equations of motion. For regulation problems of mechanical systems, which can be stabilized "shaping" only the potential energy, PBC preserves the EL structure and furthermore assigns a closed-loop energy function equal to the di erence between the energy of the system and the energy supplied by the controller. Thus, we say that stabilization is achieved via energy balancing. Unfortunately, these nice properties of EL-PBC are lost when used in other applications which require shaping of the total energy, for instance, in electrical or electromechanical systems, or even some underactuated mechanical devices. Our main objective in this paper is to develop a new PBC theory which extends to a broader class of systems the aforementioned energy-balancing stabilization mechanism and the structure invariance. Towards this end, we depart from the EL description of the systems and consider instead port-controlled Hamiltonian models, which result from the network modelling of energy-conserving lumped-parameter physical systems with independent storage elements, and strictly contain the class of EL models. ?

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Background: Surgical mortality data are collected routinely in high-income countries, yet virtually no low-or middle-income countries have outcome surveillance in place. The aim was prospectively to collect worldwide mortality data following emergency abdominal surgery, comparing findings across countries with a low, middle or high Human Development Index (HDI).Methods: This was a prospective, multicentre, cohort study. Self-selected hospitals performing emergency surgery submitted prespecified data for consecutive patients from at least one 2-week interval during July to December 2014. Postoperative mortality was analysed by hierarchical multivariable logistic regression.

Abstract. Nowadays, the Internet is a powerful means for companies to voluntarily disclose all kind of financial information. A wide academic literature exists on the field. Findings reveal that the financial information disclosed is wider than that normally required by accounting regulations. Furthermore, the disclosure on the Internet of compulsory information can be considered as a voluntary reporting practice in itself. In this paper, the information currently provided on the Internet by leading companies in different European countries is analyzed in order to make a comparative analysis. To achieve this goal, data from the biggest (market value) 20 companies in each European Union country have been collected. Then, statistical tests have been performed to determine the relationships between what we have called companies' transparency (dependent variable) and their sector, country of origin and size (independent variables). The results suggest that there is a statistically significant relationship between these three variables and the extent of voluntary disclosure (transparency) on the Internet.

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