Pathological element-based active device models and their application to symbolic analysis

This paper proposes new pathological element-based active device models which can be used in analysis tasks of linear(ized) analog circuits. Nullators and norators along with the voltage mirror-current mirror (VM-CM) pair (collectively known as pathological elements) are used to model the behavior of active devices in voltage-, current-, and mixed-mode, also considering parasitic elements. Since analog circuits are transformed to nullor-based equivalent circuits or VM-CM pairs or as a combination of both, standard nodal analysis can be used to formulate the admittance matrix. We present a formulation method in order to build the nodal admittance (NA) matrix of nullor-equivalent circuits, where the order of the matrix is given by the number of nodes minus the number of nullors. Since pathological elements are used to model the behavior of active devices, we introduce a more efficient formulation method in order to compute small-signal characteristics of pathological element-based equivalent circuits, where the order of the NA matrix is given by the number of nodes minus the number of pathological elements. Examples are discussed in order to illustrate the potential of the proposed pathological element-based active device models and the new formulation method in performing symbolic analysis of analog circuits. The improved formulation method is compared with traditional formulation methods, showing that the NA matrix is more compact and the generation of nonzero coefficients is reduced. As a consequence, the proposed formulation method is the most efficient one reported so far, since the CPU time and memory consumption is reduced when recursive determinant-expansion techniques are used to solve the NA matrix.Promep-Mexico UATLX-PTC-088Junta de Andalucía TIC-2532Ministerio de Educación y Ciencia TEC2007-67247, TEC2010-14825UC-MEXUS-CONACyT CN-09-31

Magnetic Surfaces in Stationary Axisymmetric General Relativity

In this paper a new method is derived for constructing electromagnetic surface sources for stationary axisymmetric electrovac spacetimes endowed with non-smooth or even discontinuous Ernst potentials. This can be viewed as a generalization of some classical potential theory results, since lack of continuity of the potential is related to dipole density and lack of smoothness, to monopole density. In particular this approach is useful for constructing the dipole source for the magnetic field. This formalism involves solving a linear elliptic differential equation with boundary conditions at infinity. As an example, two different models of surface densities for the Kerr-Newman electrovac spacetime are derived.Comment: 15 page

Working Environment in Nursing: Needs Improvement?

Background: Knowing the quality of life of professionals is important because it is related to job performance, better results, and greater productivity, which results in better patient care. Objective: To know the Professional Quality of Life perceived by the nurses at the Geriatric Hospital of Toledo (Spain). Method: A descriptive cross-section study was employed to measure the Professional Quality of Life of all healthcare nurses (69 in total) at the Geriatric Hospital of Toledo. The questionnaire used as a measuring instrument was the Professional Quality of Life - 35. The data obtained was analyzed by means of: descriptive statistics, single-factor ANOVA variance analysis, T Student tests, and simple and multiple regression analysis. The study was approved by both the research commission and the ethics commission at the Hospital Complex of Toledo. Participation in the study on behalf of the nursing staff was voluntary. Results: In total, 45 responses were obtained (65.2%). The overall mean score measured the perceived Professional Quality of Life to be low. In relation to the three dimensions evaluated in the study, the highest average found was in “intrinsic motivation,” followed by “workload”, and then “management support.” In the multivariate analysis, “management support” was shown as the most influential factor in the Professional Quality of Life with a 23% influence (P<0.001), followed by workload with 9% (P = 0.01). Conclusions: The professionals at the participating center perceive their workplace as having an elevated degree of responsibility, a large quantity of work, a high occurrence of rushes and fatigue, and all this with little support on behalf of management. Promotions are scarce or the policies for receiving a promotion are inadequate. The perception of Professional Quality of Life in nursing is low. The obtained results indicate a need for an organizing cultural change based on participation, motivation, and increased management support

Is university-industry collaboration biased by sex criteria?

[Abstract]: This paper studies the attitudes and decisions of research groups led by men or women towards the collaboration with firms in research and development joint projects. We worked with a sample of 420 research groups of eight regions of Spain, France and Portugal in a sequential process. First, we studied the interest of the research groups to collaborate and, then, if the final decision of collaborating with firms changed according to the sex criteria. The results show that women are worse positioned in the social networks of collaboration and commercialization with industry. Research groups led by men have around 10% higher probability of showing interest in R&D cooperation with firms. However, when men and women leaders of research groups have the same motivation to collaborate, they do not differ in their decision of collaborating. These results evidence different initial attitudes towards university-industry collaboration according to sex criteria

The funnel model of firms’ R&D cooperation with universities

[Abstract]: This paper explores the determinants of firms’ attitudes towards R&D cooperation with research groups understanding university-industry cooperation as a sequential process. In so doing, we study the determinants of both firms’ interest in and decision to engage in cooperation agreements. We applied both probit models and regression models for count data on a sample of 375 firms from Spain, Portugal and France. Although most of these firms showed interest in collaborating with universities, actually only 10% of the firms ended up cooperating with them. Our findings firstly indicate that innovative firms tend to show a more proactive attitude towards R&D collaboration. Secondly, within the group of firms interested in R&D collaboration, the firms really involved are the independent or small firms and we also provide evidence that country factors affect firms’ attitudes to R&D cooperation with universities

Nonlinear Pseudo-Supersymmetry in the Framework of N-fold Supersymmetry

We recall the importance of recognizing the different mathematical nature of various concepts relating to PT-symmetric quantum theories. After clarifying the relation between supersymmetry and pseudo-supersymmetry, we prove generically that nonlinear pseudo-supersymmetry, recently proposed by Sinha and Roy, is just a special case of N-fold supersymmetry. In particular, we show that all the models constructed by these authors have type A 2-fold supersymmetry. Furthermore, we prove that an arbitrary one-body quantum Hamiltonian which admits two (local) solutions in closed form belongs to type A 2-fold supersymmetry, irrespective of whether or not it is Hermitian, PT-symmetric, pseudo-Hermitian, and so on.Comment: 10 pages, no figures; typos correcte