Structure of the Vacuum in Deformed Supersymmetric Chiral Models

We analyze the vacuum structure of N=1/2 chiral supersymmetric theories in deformed superspace. In particular we study O'Raifeartaigh models with C-deformed superpotentials and canonical and non-canonical deformed Kahler potentials. We find conditions under which the vacuum configurations are affected by the deformations.Comment: 15 pages, minor corrections. Version to appear in JHE

A monopole solution from noncommutative multi-instantons

We extend the relation between instanton and monopole solutions of the selfduality equations in SU(2) gauge theory to noncommutative space-times. Using this approach and starting from a noncommutative multi-instanton solution we construct a U(2) monopole configuration which lives in 3 dimensional ordinary space. This configuration resembles the Wu-Yang monopole and satisfies the selfduality (Bogomol'nyi) equations for a U(2) Yang-Mills-Higgs system.Comment: 19 pages; title and abstract changed, brane interpretation corrected. Version to appear in JHE

HEOS 1 helium observations in the solar wind

Results of alpha-particle observations performed by the European satellite HEOS 1, in the period from December 9, 1968, to April 13, 1969, and from September 6, 1969, to April 15, 1970, are presented. The average bulk velocities of protons V sub p and alpha-particles V sub alpha appear to be equal; however, due to an instrumental bias, the possibility of V sub alpha being lower than V sub p cannot be ruled out. Comparison with observations of Vela 3 and Explorer 34 satellites gives evidence of a dependence of helium abundance on the solar cycle. The problem of the stability of differences between the bulk velocities of protons and alpha-particles is investigated. The behavior of alpha-particles through interplanetary shock waves is illustrated in connection with magnetic field measurements

Cu-catalyzed Si-NWS grown on “carbon paper” as anodes for Li-ion cells

The very high theoretical capacity of the silicon (4200mAh/g more than 10 times larger than graphite), environmental-friendly, abundant and low-cost, makes it a potential candidate to replace graphite in high energy density Li-ion batteries. As a drawback, silicon suffers from huge volume changes (300%) on alloying and dealloying with Li, leading a structural deformation that induces disruption. The use of nanostructured silicon materials has been shown to be an effective way to avoid this mechanical degradation of the active material. In this paper the synthesis of silicon nanowires, grown on a highly porous 3D-like carbon paper substrate by CVD using Cu as the catalyst, is presented. The use of carbon paper allows to achieve remarkable loadings of active material (2-5 mg/cm2) and, consequently, high capacity densities. The silicon electrode was investigated both morphologically and electrochemically. To improve the electrochemical performance various strategies have been carried out. It was observed that a very slow first cycle (C/40), which helps the formation of a stable solid electrolyte interphase on the silicon surface, improves the performance of the cells; nevertheless, their cycle life has been found not fully satisfactory. Morphological analysis of the Si-NWs electrodes before and after cycling showed the presence of a dense silicon layer below the nanowires which could reduce the electrical contact between the active material and the substrate

Patient involvement to explore research prioritisation and self-care management in people with periodontitis and diabetes

Aim To investigate, firstly, research priorities for people with periodontitis and those with periodontitis and diabetes. Secondary aims were to explore disease self-management barriers, difficulties and enhancers for people with periodontitis and/or diabetes, mutual learning in patient groups regarding self-care and views of academic researchers on patient-derived research prioritisation. Materials and methods Research prioritisation and self-care management was based on the James Lind Alliance workshop methodology. Participants generated and ranked research priorities and enhancers and barriers to self-care management. Semi-structured interviews were undertaken to explore the views of academic staff about patient and public involvement (PPI) and the findings from this research. Results Periodontitis patients ranked preventive educational interventions highest, whereas the top priority for those with both periodontitis and diabetes was increasing public awareness about periodontitis and systemic health links. Regarding self-care, both periodontitis and diabetes groups highly ranked the importance of being able to self-assess their condition and efficacy of management. Important barriers for the diabetes patients were psychological issues, while for periodontitis patients, the main barrier was receiving conflicting or lacking information. Both groups reported that shared learning helped to develop a better understanding of their conditions and improved management. Academics believed it was essential to involve patients in developing research and most felt the findings would influence their institutions' research priorities; however, they would not change their own research only based on patients' perspectives. Conclusions The workshops led to new insights for research priorities and approaches for health self-management. PPI should be further investigated across oral health applications

Semiempirical Modeling of Reset Transitions in Unipolar Resistive-Switching based Memristors

We have measured the transition process from the high to low resistivity states, i.e., the reset process of resistive switching based memristors based on Ni/HfO2/Si-n+ structures, and have also developed an analytical model for their electrical characteristics. When the characteristic curves are plotted in the current-voltage (I-V) domain a high variability is observed. In spite of that, when the same curves are plotted in the charge-flux domain (Q-phi), they can be described by a simple model containing only three parameters: the charge (Qrst) and the flux (rst) at the reset point, and an exponent, n, relating the charge and the flux before the reset transition. The three parameters can be easily extracted from the Q-phi plots. There is a strong correlation between these three parameters, the origin of which is still under study

Tpk3 and Snf1 protein kinases regulate Rgt1 association with Saccharomyces cerevisiae HXK2 promoter

Hexokinase 2 is an essential factor for signalling repression through the Saccharomyces cerevisiae high-glucose sensing pathway. The main regulatory mechanism that controls the HXK2 gene expression in yeast is mediated by the Rgt1 and Med8 transcription factors, which repress HXK2 expression in low-glucose containing media. In this study, we show that the repression activity of Rgt1 is regulated by Snf1 and Tpk3 protein kinases. Binding of Rgt1 to the HXK2 promoter requires Rgt1 phosphorylation by Snf1 or by an Snf1-dependent protein kinase. Conversely, Rgt1 hyperphosphorylation by the Tpk3 or by a Tpk3-dependent protein kinase dissociates Rgt1 from the repressor complex. Two-hybrid and chromatin immunoprecipitation experiments indicate that an Snf1-dependent interaction between Rgt1 and Med8 in the repressor complex is also essential for Rgt1 repression. The repression of HXK2 transcription by Rgt1 likely occurs through the formation of a DNA loop in the HXK2 locus, spanning the promoter and coding regions. These results suggest that a novel silent-chromatin loop is responsible for Rgt1-dependent transcriptional regulation of the HXK2 gene

Maude: specification and programming in rewriting logic

Maude is a high-level language and a high-performance system supporting executable specification and declarative programming in rewriting logic. Since rewriting logic contains equational logic, Maude also supports equational specification and programming in its sublanguage of functional modules and theories. The underlying equational logic chosen for Maude is membership equational logic, that has sorts, subsorts, operator overloading, and partiality definable by membership and equality conditions. Rewriting logic is reflective, in the sense of being able to express its own metalevel at the object level. Reflection is systematically exploited in Maude endowing the language with powerful metaprogramming capabilities, including both user-definable module operations and declarative strategies to guide the deduction process. This paper explains and illustrates with examples the main concepts of Maude's language design, including its underlying logic, functional, system and object-oriented modules, as well as parameterized modules, theories, and views. We also explain how Maude supports reflection, metaprogramming and internal strategies. The paper outlines the principles underlying the Maude system implementation, including its semicompilation techniques. We conclude with some remarks about applications, work on a formal environment for Maude, and a mobile language extension of Maude