The effects of European regulatory networks on the bureaucratic autonomy of national regulatory authorities

The politics and administration of institutional chang

Immunological selection of variant mouse lymphoid cells with altered glucocorticoid responsiveness.

We have devised an immunological procedure to separate cells on the basis of expression of mouse mammary tumor virus (MMTV) gene products. Plastic petri dishes coated with specific antibodies against MMTV proteins bind cells with an efficiency that correlates with the level of MMTV gene expression. Glucocorticoid-sensitive mouse thymoma cell line W7 was infected with MMTV. Clones from the infected population retain the relatively slow cytolytic glucocorticoid response and, in addition, exhibit a rapid induction of MMTV-specific RNA and proteins. By combining our immunological selection with the selection for resistance to hormone-mediated cytolysis, we have isolated variant cells which are resistant to the cytotoxic effect of glucocorticoids but which retain the induction of viral gene products and must therefore have a functional glucocorticoid receptor protein

Teaching Threshold Concepts in Virtual Reality: Exploring the Conceptual Requirements for Systems Design.

In a complex world students need to be equipping with a range of capabilities that will enable them to be critical and flexible learners and citizens. The central research objective in this paper is to explore the argument that virtual reality (VR) technologies, collaborative learning approaches and recognition of the values and importance of thresholds to learning are components that can equip students in and for the future. Threshold concepts are specific concepts which are identified as essential in the acquisition of thinking, learning and communication of understanding within a specific subject of learning. Threshold experiences occur when learners identify moments of “learning leaps” which are cognitive transformations or changes in conceptual role for the learner, enabling them to work at higher levels of abstraction and creativity. Virtual reality technology is increasingly applied in education and can be used to test multiple threshold concepts and applied to open problems that allow for low-stress and real-time interactions as well as supporting collaborative groups with rapid interactions. Applications built on VR can engage, immerse, and guide learners in ways not yet undertaken in the education of threshold concepts. Through literature review we explore the definitions of threshold concepts, VR technologies, and the opportunities for teaching threshold concepts using VR technologies. We additionally predict possible limitations of the technologies. Further, we propose a systems design approach as informed by our literature review

Deformabilidad en hormigones con agregados reciclados

Diversos trabajos han demostrado la factibilidad de elaborar hormigones con agregados reciclados, sin embargo sobre algunos aspectos poco explorados aún existen informaciones contrapuestas. Entre ellos se destacan el comportamiento diferido del hormigón (contracción y fluencia) y la capacidad de deformación en tracción (extensibilidad). Estas propiedades afectan directamente el grado de fisuración que puede tener una estructura de hormigón, lo que adquiere una significativa relevancia en la práctica, al considerar su vida en servicio. En este trabajo se presenta un estudio de la deformabilidad de hormigones que contienen 50 o 100 % de agregado grueso obtenido a partir de la trituración de losas de pavimento. Los resultados se comparan con los de otros dos hormigones elaborados con idénticas proporciones de materiales componentes variando el tipo de agregado grueso, piedra partida granítica o piedra partida cuarcítica. Se evaluaron la resistencia a tracción, la extensibilidad en flexión bajo cargas rápidas, y la fluencia en compresión. Bajo cargas de corta duración se encontró una deformabilidad creciente en el hormigón con mayor contenido de agregados reciclados, tanto en flexotracción como en compresión; también se midieron mayores valores de contracción libre y de fluencia. A partir de los resultados surge que es posible estimar la deformabilidad del hormigón con agregados reciclados siguiendo criterios similares a los aplicados en hormigones con agregados naturales; las diferencias de deformabilidad se pueden justificar considerando la menor rigidez del agregado reciclado.Different works have demonstrated the feasibility of elaborating concrete with recycled aggregates, nevertheless there is still opposite information about some aspects that have not been widely studied. The differed behaviour (shrinkage and creep) and the deformation capacity in tension (extensibility) of concrete are among them. These properties have a direct effect over the degree of cracking that can have a concrete structure so, considering its service life, they acquire a significant relevance in practice. This paper presents a study on the deformability of concretes that contain 50 or 100 % of coarse aggregate obtained from crushed pavement slabs. The results are compared with those obtained on other two concretes prepared with the same mixture proportions varying only the type of coarse aggregate, granitic crushed stone or quartzitic crushed stone. The tensile strength, extensibility in flexure under rapid rate of loading and creep in compression were evaluated. It was found that under short term loads the deformability of concrete increases with the content of recycled aggregates, both in flexure and in compression, grater values of free shrinkage and creep were also measured. From the obtained results it appears that the deformability of concrete with recycled aggregates can be estimated following the same criteria applied to concrete with natural aggregate, the differences in deformability can be justified considering the lower stiffness of the recycled aggregate

A Quantum Mechanical Model of the Reissner-Nordstrom Black Hole

We consider a Hamiltonian quantum theory of spherically symmetric, asymptotically flat electrovacuum spacetimes. The physical phase space of such spacetimes is spanned by the mass and the charge parameters $M$ and $Q$ of the Reissner-Nordstr\"{o}m black hole, together with the corresponding canonical momenta. In this four-dimensional phase space, we perform a canonical transformation such that the resulting configuration variables describe the dynamical properties of Reissner-Nordstr\"{o}m black holes in a natural manner. The classical Hamiltonian written in terms of these variables and their conjugate momenta is replaced by the corresponding self-adjoint Hamiltonian operator, and an eigenvalue equation for the ADM mass of the hole, from the point of view of a distant observer at rest, is obtained. Our eigenvalue equation implies that the ADM mass and the electric charge spectra of the hole are discrete, and the mass spectrum is bounded below. Moreover, the spectrum of the quantity $M^2-Q^2$ is strictly positive when an appropriate self-adjoint extension is chosen. The WKB analysis yields the result that the large eigenvalues of the quantity $\sqrt{M^2-Q^2}$ are of the form $\sqrt{2n}$, where $n$ is an integer. It turns out that this result is closely related to Bekenstein's proposal on the discrete horizon area spectrum of black holes.Comment: 37 pages, Plain TeX, no figure