445 research outputs found
Learning from sustainable development: education in the light of public issues
Education for sustainable development (ESD) is increasingly affecting environmental education policy and practice. In this article we show how sustainable development is mainly seen as a problem that can be tackled by applying the proper learning processes and how this perspective translates sustainability issues into learning problems of individuals. We present a different perspective on education in the context of sustainable development based on novel ways of thinking about citizenship education and emphasizing the importance of presenting issues of sustainable development as ‘public issues’, as matters of public concern. From this point of view, the focus is no longer on the competences that citizens must achieve, but on the democratic nature of the spaces and practices in which participation and citizenship can develop
Robust Dropping Criteria for F-norm Minimization Based Sparse Approximate Inverse Preconditioning
Dropping tolerance criteria play a central role in Sparse Approximate Inverse
preconditioning. Such criteria have received, however, little attention and
have been treated heuristically in the following manner: If the size of an
entry is below some empirically small positive quantity, then it is set to
zero. The meaning of "small" is vague and has not been considered rigorously.
It has not been clear how dropping tolerances affect the quality and
effectiveness of a preconditioner . In this paper, we focus on the adaptive
Power Sparse Approximate Inverse algorithm and establish a mathematical theory
on robust selection criteria for dropping tolerances. Using the theory, we
derive an adaptive dropping criterion that is used to drop entries of small
magnitude dynamically during the setup process of . The proposed criterion
enables us to make both as sparse as possible as well as to be of
comparable quality to the potentially denser matrix which is obtained without
dropping. As a byproduct, the theory applies to static F-norm minimization
based preconditioning procedures, and a similar dropping criterion is given
that can be used to sparsify a matrix after it has been computed by a static
sparse approximate inverse procedure. In contrast to the adaptive procedure,
dropping in the static procedure does not reduce the setup time of the matrix
but makes the application of the sparser for Krylov iterations cheaper.
Numerical experiments reported confirm the theory and illustrate the robustness
and effectiveness of the dropping criteria.Comment: 27 pages, 2 figure
Economies of space and the school geography curriculum
This paper is about the images of economic space that are found in school curricula. It suggests the importance for educators of evaluating these representations in terms of the messages they contain about how social processes operate. The paper uses school geography texts in Britain since the 1970s to illustrate the different ways in which economic space has been represented to students, before exploring some alternative resources that could be used to provide a wider range of representations of economic space. The paper highlights the continued importance of understanding the politics of school knowledge
Angiotensin II activates at least two tyrosine kinases in rat liver epithelial cells. Separation of the major calcium-regulated tyrosine kinase from p125(FAK)
In rat liver epithelial cell lines (WB or GN4), angiotensin II (Ang II) stimulates cytosolic tyrosine kinase activity, in part, through a calcium-dependent mechanism. In other cell types, selected hormones that activate Gi- or Gq-coupled receptors stimulate the soluble tyrosine kinase, p125FAK. Immunoprecipitation of p125FAK from Ang II-activated GN4 cells demonstrated a doubling of p125FAK kinase activity. However, an additional Ang II-activated tyrosine kinase (or kinases) representing the majority of the total activity was detected when the remaining cell lysate, immunodepleted of p125FAK, was reimmunoprecipitated with an anti-phosphotyrosine antibody. Cytochalasin D pretreatment blocks G-protein receptor-dependent tyrosine phosphorylation in Swiss 3T3 cells. While cytochalasin D decreased the Tyr(P) content of 65-75-kDa substrates in Ang II-treated GN4 cells, it did not diminish tyrosine phosphorylation of 115-130-kDa substrates, again suggesting activation of at least two tyrosine kinase pathways in GN4 cells. To search for additional Ang II-activated enzymes, we used molecular techniques to identify 20 tyrosine kinase sequences in these cell lines. None was the major cytosolic enzyme activated by Ang II. Specifically, JAK2, which had been shown by others to be stimulated by Ang II in smooth muscle cells, was not activated by Ang II in GN4 cells. Finally, we purified Tyr(P)-containing tyrosine kinases from Ang II-treated cells, using anti-Tyr(P) and ATP affinity resins; 80% of the tyrosine kinase activity migrated as a single 115-120-kDa tyrosine-phosphorylated protein immunologically distinct from p125FAK. In summary, Ang II activates at least two separate tyrosine kinases in rat liver epithelial cells; p125FAK and a presumably novel, cytosolic 115-120-kDa protein referred to as the calcium-dependent tyrosine kinase
Integrated acoustic immunoaffinity-capture (IAI) platform for detection of PSA from whole blood samples.
On-chip detection of low abundant protein biomarkers is of interest to enable point-of-care diagnostics. Using a simple form of integration, we have realized an integrated microfluidic platform for the detection of prostate specific antigen (PSA), directly in anti-coagulated whole blood. We combine acoustophoresis-based separation of plasma from undiluted whole blood with a miniaturized immunoassay system in a polymer manifold, demonstrating improved assay speed on our Integrated Acoustic Immunoaffinity-capture (IAI) platform. The IAI platform separates plasma from undiluted whole blood by means of acoustophoresis and provides cell free plasma of clinical quality at a rate of 10 uL/min for an online immunoaffinity-capture of PSA on a porous silicon antibody microarray. The whole blood input (hematocrit 38-40%) rate was 50 μl min(-1) giving a plasma volume fraction yield of ≈33%. PSA was immunoaffinity-captured directly from spiked female whole blood samples at clinically significant levels of 1.7-100 ng ml(-1) within 15 min and was subsequently detected via fluorescence readout, showing a linear response over the entire range with a coefficient of variation of 13%
The global dimension in education and education for global citizenship: genealogy and critique
Encouraged by transnational organisations, curriculum policy-makers in the UK have called for curricula in schools and higher education to include a global dimension and education for global citizenship that will prepare students for life in a global society and work in a global economy. We argue that this call is rhetorically operating as a ‘nodal point’ in policy discourse a floating signifier that different discourses attempt to cover with meaning. This rhetoric attempts to bring three educational traditions together: environmental education, development education and citizenship education. We explore this new point of arrival and departure and some of the consequences and critiques
Please mind the gap: students’ perspectives of the transition in academic skills between A-level and degree level geography
This paper explores first-year undergraduates’ perceptions of the transition from studying geography at pre-university level to studying for a degree. This move is the largest step students make in their education, and the debate about it in the UK has been reignited due to the government’s planned changes to A-level geography. However, missing from most of this debate is an appreciation of the way in which geography students themselves perceive their transition to university. This paper begins to rectify this absence. Using student insights, we show that their main concern is acquiring the higher level skills required for university learning
Recommended from our members
A genome annotation-driven approach to cloning the human ORFeome.
We have developed a systematic approach to generating cDNA clones containing full-length open reading frames (ORFs), exploiting knowledge of gene structure from genomic sequence. Each ORF was amplified by PCR from a pool of primary cDNAs, cloned and confirmed by sequencing. We obtained clones representing 70% of genes on human chromosome 22, whereas searching available cDNA clone collections found at best 48% from a single collection and 60% for all collections combined.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are
<i>Gaia</i> Data Release 1. Summary of the astrometric, photometric, and survey properties
Context. At about 1000 days after the launch of Gaia we present the first Gaia data release, Gaia DR1, consisting of astrometry and photometry for over 1 billion sources brighter than magnitude 20.7.
Aims. A summary of Gaia DR1 is presented along with illustrations of the scientific quality of the data, followed by a discussion of the limitations due to the preliminary nature of this release.
Methods. The raw data collected by Gaia during the first 14 months of the mission have been processed by the Gaia Data Processing and Analysis Consortium (DPAC) and turned into an astrometric and photometric catalogue.
Results. Gaia DR1 consists of three components: a primary astrometric data set which contains the positions, parallaxes, and mean proper motions for about 2 million of the brightest stars in common with the HIPPARCOS and Tycho-2 catalogues – a realisation of the Tycho-Gaia Astrometric Solution (TGAS) – and a secondary astrometric data set containing the positions for an additional 1.1 billion sources. The second component is the photometric data set, consisting of mean G-band magnitudes for all sources. The G-band light curves and the characteristics of ∼3000 Cepheid and RR-Lyrae stars, observed at high cadence around the south ecliptic pole, form the third component. For the primary astrometric data set the typical uncertainty is about 0.3 mas for the positions and parallaxes, and about 1 mas yr−1 for the proper motions. A systematic component of ∼0.3 mas should be added to the parallax uncertainties. For the subset of ∼94 000 HIPPARCOS stars in the primary data set, the proper motions are much more precise at about 0.06 mas yr−1. For the secondary astrometric data set, the typical uncertainty of the positions is ∼10 mas. The median uncertainties on the mean G-band magnitudes range from the mmag level to ∼0.03 mag over the magnitude range 5 to 20.7.
Conclusions. Gaia DR1 is an important milestone ahead of the next Gaia data release, which will feature five-parameter astrometry for all sources. Extensive validation shows that Gaia DR1 represents a major advance in the mapping of the heavens and the availability of basic stellar data that underpin observational astrophysics. Nevertheless, the very preliminary nature of this first Gaia data release does lead to a number of important limitations to the data quality which should be carefully considered before drawing conclusions from the data
- …