340 research outputs found
The employability of non-native-speaker teachers of EFL: A UK survey
The native speaker still has a privileged position in English language teaching, representing both the model speaker and the ideal teacher. Non-native-speaker teachers of English are often perceived as having a lower status than their native-speaking counterparts, and have been shown to face discriminatory attitudes when applying for teaching jobs. To date, research into the employment of non-native-speaker teachers has been carried out only in the United States; this study extends that research by providing data on the United Kingdom. Questionnaires were distributed to those responsible for recruitment at English language teaching institutions in the UK in order to investigate the extent to which employers regard being a native English speaker as an important criterion when making hiring decisions. 72.3% of the 90 respondents judged the 'native English speaker criterion' to be either moderately or very important. The conclusion that employers regard this criterion as important was shown to apply to the whole sample as well as to the separate groups of private language schools only and universities only. As a pre-interview criterion, the 'native English speaker criterion' thus excludes competent English language teachers from consideration in the recruitment process. © 2007 Elsevier Ltd. All rights reserved
A versatile, automated and high-throughput drug screening platform for zebrafish embryos
Zebrafish provide a unique opportunity for drug screening in living animals, with the fast developing, transparent embryos allowing for relatively high-throughput, microscopy-based screens. However, the limited availability of rapid, flexible imaging and analysis platforms has limited the use of zebrafish in drug screens. We have developed an easy-to-use, customisable automated screening procedure suitable for high-throughput phenotype-based screens of live zebrafish. We utilised the WiScan® Hermes High Content Imaging System to rapidly acquire brightfield and fluorescent images of embryos, and the WiSoft® Athena Zebrafish Application for analysis, which harnesses an Artificial Intelligence-driven algorithm to automatically detect fish in brightfield images, identify anatomical structures, partition the animal into regions, and exclusively select the desired side-oriented fish. Our initial validation combined structural analysis with fluorescence images to enumerate GFP-tagged haematopoietic stem and progenitor cells in the tails of embryos, which correlated with manual counts. We further validated this system to assess the effects of genetic mutations and x-ray irradiation in high content using a wide range of assays. Further, we performed simultaneous analysis of multiple cell types using dual fluorophores in high throughput. In summary, we demonstrate a broadly applicable and rapidly customisable platform for high-content screening in zebrafish
Community standards for open cell migration data
Cell migration research has become a high-content field. However, the quantitative information encapsulated in these complex and high-dimensional datasets is not fully exploited owing to the diversity of experimental protocols and non-standardized output formats. In addition, typically the datasets are not open for reuse. Making the data open and Findable, Accessible, Interoperable, and Reusable (FAIR) will enable meta-analysis, data integration, and data mining. Standardized data formats and controlled vocabularies are essential for building a suitable infrastructure for that purpose but are not available in the cell migration domain. We here present standardization efforts by the Cell Migration Standardisation Organisation (CMSO), an open community-driven organization to facilitate the development of standards for cell migration data. This work will foster the development of improved algorithms and tools and enable secondary analysis of public datasets, ultimately unlocking new knowledge of the complex biological process of cell migration
Reconstructing biblical military campaigns using geomagnetic field data.
The Hebrew Bible and other ancient Near Eastern texts describe Egyptian, Aramean, Assyrian, and Babylonian military campaigns to the Southern Levant during the 10th to sixth centuries BCE. Indeed, many destruction layers dated to this period have been unearthed in archaeological excavations. Several of these layers are securely linked to specific campaigns and are widely accepted as chronological anchors. However, the dating of many other destruction layers is often debated, challenging the ability to accurately reconstruct the different military campaigns and raising questions regarding the historicity of the biblical narrative. Here, we present a synchronization of the historically dated chronological anchors and other destruction layers and artifacts using the direction and/or intensity of the ancient geomagnetic field recorded in mud bricks from 20 burnt destruction layers and in two ceramic assemblages. During the period in question, the geomagnetic field in this region was extremely anomalous with rapid changes and high-intensity values, including spikes of more than twice the intensity of today's field. The data are useful in the effort to pinpoint these short-term variations on the timescale, and they resolve chronological debates regarding the campaigns against the kingdoms of Israel and Judah, the relationship between the two kingdoms, and their administrations
High-Resolution Quantification of Focal Adhesion Spatiotemporal Dynamics in Living Cells
Focal adhesions (FAs) are macromolecular complexes that provide a linkage between the cell and its external environment. In a motile cell, focal adhesions change size and position to govern cell migration, through the dynamic processes of assembly and disassembly. To better understand the dynamic regulation of focal adhesions, we have developed an analysis system for the automated detection, tracking, and data extraction of these structures in living cells. This analysis system was used to quantify the dynamics of fluorescently tagged Paxillin and FAK in NIH 3T3 fibroblasts followed via Total Internal Reflection Fluorescence Microscopy (TIRF). High content time series included the size, shape, intensity, and position of every adhesion present in a living cell. These properties were followed over time, revealing adhesion lifetime and turnover rates, and segregation of properties into distinct zones. As a proof-of-concept, we show how a single point mutation in Paxillin at the Jun-kinase phosphorylation site Serine 178 changes FA size, distribution, and rate of assembly. This study provides a detailed, quantitative picture of FA spatiotemporal dynamics as well as a set of tools and methodologies for advancing our understanding of how focal adhesions are dynamically regulated in living cells. A full, open-source software implementation of this pipeline is provided at http://gomezlab.bme.unc.edu/tools
Long-term postharvest aroma evolution of tomatoes with the alcobaça (alc) mutation
The postharvest evolution of Penjar tomatoes has been studied in four accessions representative of the variability of the varietal type. The long-term shelf life of these materials, which carry the alc allele, was confirmed with 31.2-59.1% of commercial fruits after 6 months of effective conservation at room temperature and a limited loss of weight (21.1-27.9%). Aroma in Penjar tomatoes is differentiated from other tomato varieties by a characteristic 'sharp-floral' aroma descriptor. The evolution of the 'sharp-floral' aroma during postharvest showed a peak of intensity at 2 months of postharvest, though in one accession a delay of 2 months in this response was detected. Out of 25 volatiles analysed, including main and background notes, a reverse iPLS variable selection revealed that the main candidates behind this aromatic behaviour are ¿-terpineol, trans-2-hexenal, 6-methyl-5-hepten-2-one, trans-2-octenal, ¿-pinene, ß-ionone, 2 + 3-methylbutanol and phenylacetaldehyde. Between harvest and 2 months postharvest, most compounds reduced considerably their concentration, while the intensity of the 'sharp-floral' descriptor increased, which means that probably there is a rearrangement of the relative concentrations among volatiles that may lead to masking/unmasking processes. © 2011 Springer-Verlag.This work was supported by grants from the Conselleria de Agricultura, Pesca y Alimentacio de la Comunidad Valenciana, the Fundacion de la Comunidad Valenciana para la Investigacion Agroalimentaria (AGROALIMED) and from the Departament d'Agricultura, Alimentacio i Accio Rural (DAR) de la Generalitat de Catalunya.Casals Missio, J.; Cebolla Cornejo, J.; Rosello Ripolles, S.; Beltran Arandes, J.; Casanas, F.; Nuez Viñals, F. (2011). Long-term postharvest aroma evolution of tomatoes with the alcobaça (alc) mutation. 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Harnessing anthocyanin-rich fruit: a visible reporter for tracing virus-induced gene silencing in pepper fruit
Drosophila S2 Cells Are Non-Permissive for Vaccinia Virus DNA Replication Following Entry via Low pH-Dependent Endocytosis and Early Transcription
Vaccinia virus (VACV), a member of the chordopox subfamily of the Poxviridae, abortively infects insect cells. We have investigated VACV infection of Drosophila S2 cells, which are useful for protein expression and genome-wide RNAi screening. Biochemical and electron microscopic analyses indicated that VACV entry into Drosophila S2 cells depended on the VACV multiprotein entry-fusion complex but appeared to occur exclusively by a low pH-dependent endocytic mechanism, in contrast to both neutral and low pH entry pathways used in mammalian cells. Deep RNA sequencing revealed that the entire VACV early transcriptome, comprising 118 open reading frames, was robustly expressed but neither intermediate nor late mRNAs were made. Nor was viral late protein synthesis or inhibition of host protein synthesis detected by pulse-labeling with radioactive amino acids. Some reduction in viral early proteins was noted by Western blotting. Nevertheless, synthesis of the multitude of early proteins needed for intermediate gene expression was demonstrated by transfection of a plasmid containing a reporter gene regulated by an intermediate promoter. In addition, expression of a reporter gene with a late promoter was achieved by cotransfection of intermediate genes encoding the late transcription factors. The requirement for transfection of DNA templates for intermediate and late gene expression indicated a defect in viral genome replication in VACV-infected S2 cells, which was confirmed by direct analysis. Furthermore, VACV-infected S2 cells did not support the replication of a transfected plasmid, which occurs in mammalian cells and is dependent on all known viral replication proteins, indicating a primary restriction of DNA synthesis
Scaling behaviour for the water transport in nanoconfined geometries
The transport of water in nanoconfined geometries is different from bulk phase and has tremendous implications in nanotechnology and biotechnology. Here molecular dynamics is used to compute the self-diffusion coefficient D of water within nanopores, around nanoparticles, carbon nanotubes and proteins. For almost 60 different cases, D is found to scale linearly with the sole parameter theta as D(theta)=DB[1+(DC/DB-1)theta], with DB and DC the bulk and totally confined diffusion of water, respectively. The parameter theta is primarily influenced by geometry and represents the ratio between the confined and total water volumes. The D(theta) relationship is interpreted within the thermodynamics of supercooled water. As an example, such relationship is shown to accurately predict the relaxometric response of contrast agents for magnetic resonance imaging. The D(theta) relationship can help in interpreting the transport of water molecules under nanoconfined conditions and tailoring nanostructures with precise modulation of water mobility
Identification of Novel Pro-Migratory, Cancer-Associated Genes Using Quantitative, Microscopy-Based Screening
Background: Cell migration is a highly complex process, regulated by multiple genes, signaling pathways and external stimuli. To discover genes or pharmacological agents that can modulate the migratory activity of cells, screening strategies that enable the monitoring of diverse migratory parameters in a large number of samples are necessary. Methodology: In the present study, we describe the development of a quantitative, high-throughput cell migration assay, based on a modified phagokinetic tracks (PKT) procedure, and apply it for identifying novel pro-migratory genes in a cancer-related gene library. In brief, cells are seeded on fibronectin-coated 96-well plates, covered with a monolayer of carboxylated latex beads. Motile cells clear the beads, located along their migratory paths, forming tracks that are visualized using an automated, transmitted-light screening microscope. The tracks are then segmented and characterized by multi-parametric, morphometric analysis, resolving a variety of morphological and kinetic features. Conclusions: In this screen we identified 4 novel genes derived from breast carcinoma related cDNA library, whose over-expression induces major alteration in the migration of the stationary MCF7 cells. This approach can serve for high throughput screening for novel ways to modulate cellular migration in pathological states such as tumor metastasis and invasion
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