18,430 research outputs found
Cooperative Research As a Strategy for University Teacher Training. A Case Study of Lesson and Learning Study
This paper presents the possibilities offered by Lesson and Learning Studies for training and for improving and generating knowledge by reconstructing the practical knowledge of teachers. Firstly, we provide a summary of the concept of practical knowledge and the tradition of teachers researching their own practice. This is followed by some principles of Lesson and Learning Studies, with examples of their possibilities for university teacher training taken from a case study of our own practice during a university master's degree
Effects of a radially varying electrical conductivity on 3D numerical dynamos
The transition from liquid metal to silicate rock in the cores of the
terrestrial planets is likely to be accompanied by a gradient in the
composition of the outer core liquid. The electrical conductivity of a volatile
enriched liquid alloy can be substantially lower than a light-element-depleted
fluid found close to the inner core boundary. In this paper, we investigate the
effect of radially variable electrical conductivity on planetary dynamo action
using an electrical conductivity that decreases exponentially as a function of
radius. We find that numerical solutions with continuous, radially outward
decreasing electrical conductivity profiles result in strongly modified flow
and magnetic field dynamics, compared to solutions with homogeneous electrical
conductivity. The force balances at the top of the simulated fluid determine
the overall character of the flow. The relationship between Coriolis and
Lorentz forces near the outer boundary controls the flow and magnetic field
intensity and morphology of the system. Our results imply that a low
conductivity layer near the top of Mercury's liquid outer core is consistent
with its weak magnetic field.Comment: 30 pages, 11 figures, 2 tables. To be published in Physics of Earth
and Planetary Interiors (PEPI)
The tension in light of vacuum dynamics in the Universe
Despite the outstanding achievements of modern cosmology, the classical
dispute on the precise value of , which is the first ever parameter of
modern cosmology and one of the prime parameters in the field, still goes on
and on after over half a century of measurements. Recently the dispute came to
the spotlight with renewed strength owing to the significant tension (at
c.l.) between the latest Planck determination obtained from the CMB
anisotropies and the local (distance ladder) measurement from the Hubble Space
Telescope (HST), based on Cepheids. In this work, we investigate the impact of
the running vacuum model (RVM) and related models on such a controversy. For
the RVM, the vacuum energy density carries a mild dependence
on the cosmic expansion rate, i.e. , which allows to
ameliorate the fit quality to the overall cosmological
observations as compared to the concordance CDM model. By letting the
RVM to deviate from the vacuum option, the equation of state continues
to be favored by the overall fit. Vacuum dynamics also predicts the following:
i) the CMB range of values for is more favored than the local ones, and
ii) smaller values for . As a result, a better account for the LSS
structure formation data is achieved as compared to the CDM, which is
based on a rigid (i.e. non-dynamical) term.Comment: Accepted for publication in Phys. Lett. B. Significantly extended
discussion, two figures and references adde
ODESGS, an Environment for the Annotation and Design of Grid Environments
ODESGS is an ongoing work carried out in the Ontogrid Project (FP6-511513). It is the extension of the ODESWS Environment [1] developed in the context of the Esperonto Project (IST-2001-34372) and is an implementation of the ODESGS Framework [2]. This framework is being developed for the markup of Grid Services (GS) and creation of new complex Semantic Grid Services (SGS) from these annotated GS, to enable their discovery and (semi)automatic composition. It also formalizes Virtual Organizations (VO) with it, defined, since the appearance of OGSA, as a set of the services that are operated and shared. Therefore, VO description is closely attached to the descriptions made to each GS individually, plus additional information about the relationships and policies between these services. Note that what we mean as markup of VO and SGS is the association of these elements with an instance of the ODESGS Ontology
Ontology Access Provisioning in Grid Environments
The increase of use of semantic technologies has reached almost every computer science related field, including the grid computing field . The next generation Grid should virtualise the notion of distribution in computation, storage, and communication over unlimited resources with well defined computational semantics. A Grid node may provide new services, functions or even new concepts that are unknown to clients. The semantics of such services are defined by means of Ontologies [Gruber, 1993; Gómez-Pérez et al., 2003]. Thus providing the appropriate means for accessing and using Ontologies in the Grid is fundamental if semantic technologies are to be used. So, the transition from monolithic, centralized ontology services to a virtual organization of Grid compliant and Grid aware ontology services that can coordinate and cooperate with each other is crucial to progress towards the Semantic Grid [De Roure et al., 2005]
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