9,815 research outputs found
Asking the experts : developing and validating parental diaries to assess children's minor injuries
The methodological issues involved in parental reporting of events in children's everyday lives are discussed with reference to the development and validation of an incident diary, collecting concurrent data on minor injuries in a community study of children under eight years old. Eighty-two mothers participated in a comparison over nine days of daily telephone interviews and structured incident diaries. Telephone methods resulted in more missing data, and participants in both groups expressed a preference for the diary method. This diary was then validated on a sample of 56 preschool and school-aged children by comparing injury recording by a research health visitor with that of their mothers. Each failed to report some injuries, but there was good agreement overall, and in descriptive data on injuries reported by both. Parental diaries have the potential to provide rich data, of acceptable validity, on minor events in everyday life
Parameter inference in mechanistic models of cellular regulation and signalling pathways using gradient matching
A challenging problem in systems biology is parameter inference in mechanistic models of signalling pathways. In the present article, we investigate an approach based on gradient matching and nonparametric Bayesian modelling with Gaussian processes. We evaluate the method on two biological systems, related to the regulation of PIF4/5 in Arabidopsis thaliana, and the JAK/STAT signal transduction pathway
Six questions on the construction of ontologies in biomedicine
(Report assembled for the Workshop of the AMIA Working Group on Formal Biomedical Knowledge Representation in connection with AMIA Symposium, Washington DC, 2005.)
Best practices in ontology building for biomedicine have been frequently discussed in recent years. However there is a range of seemingly disparate views represented by experts in the field. These views not only reflect the different uses to which ontologies are put, but also the experiences and disciplinary background of these experts themselves. We asked six questions related to biomedical ontologies to what we believe is a representative sample of ontologists in the biomedical field and came to a number conclusions which we believe can help provide an insight into the practical problems which ontology builders face today
Far-field Unlabelled Super-Resolution Imaging with Superoscillatory Illumination
Unlabelled super-resolution is the next grand challenge in imaging. Stimulated emission depletion and single-molecule microscopies have revolutionised the life sciences but are still limited by the need for reporters (labels) embedded within the sample. While the Veselago-Pendry âsuper-lensâ using a negative-index metamaterial is a promising idea for imaging beyond the diffraction limit, there are substantial technological challenges to its realisation. Another route to far-field subwavelength focusing is using optical superoscillations: engineered interference of multiple coherent waves creating an, in principle, arbitrarily small hotspot. Here we demonstrate microscopy with superoscillatory illumination of the object and describe its underlying principles. We show that far-field images taken with superoscillatory
illumination are themselves superoscillatory and hence can reveal fine structural details of the object that are lost in conventional far-field imaging. We show that the resolution of a superoscillatory microscope is determined by the size of the hotspot, rather than the bandwidth of the optical instrument. We demonstrate high-frame-rate polarisation-contrast imaging of unmodified living cells with resolution significantly exceeding that achievable with conventional instruments. This non-algorithmic, low-phototoxicity imaging technology is a powerful tool both for biological research and for super-resolution imaging of samples that do not allow labelling, such as the interior of silicon chips
Mathematical and computer modeling of electro-optic systems using a generic modeling approach
The conventional approach to modelling electro-optic sensor systems is to develop separate models for individual systems or classes of system, depending on the detector technology employed in the sensor and the application. However, this ignores commonality in design and in components of these systems. A generic approach is presented for modelling a variety of sensor systems operating in the infrared waveband that also allows systems to be modelled with different levels of detail and at different stages of the product lifecycle. The provision of different model types (parametric and image-flow descriptions) within the generic framework can allow valuable insights to be gained
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Semantic memory redux: an experimental test of hierarchical category representation
Four experiments investigated the classic issue in semantic memory of whether people organize categorical information in hierarchies and use inference to retrieve information from them, as proposed by Collins & Quillian (1969). Past evidence has focused on RT to confirm sentences such as âAll birds are animalsâ or âCanaries breathe.â However, confounding variables such as familiarity and associations between the terms have led to contradictory results. Our experiments avoided such problems by teaching subjects novel materials. Experiment 1 tested an implicit hierarchical structure in the features of a set of studied objects (e.g., all brown objects were large). Experiment 2 taught subjects nested categories of artificial bugs. In Experiment 3, subjects learned a tree structure of novel category hierarchies. In all three, the results differed from the predictions of the hierarchical inference model. In Experiment 4, subjects learned a hierarchy by means of paired associates of novel category names. Here we finally found the RT signature of hierarchical inference. We conclude that it is possible to store information in a hierarchy and retrieve it via inference, but it is difficult and avoided whenever possible. The results are more consistent with feature comparison models than hierarchical models of semantic memory
Simulations and experimental demonstrations of encoding for X-ray coherent scattering
Diffraction data may be measured using approaches that lead to ambiguity in the interpretation of scattering distributions. Thus, the encoding and decoding of coherent scattering distributions have been considered with a view to enabling unequivocal data interpretation. Two encoding regimes are considered, where encoding occurs between the X-ray source and sample, and where the encoder is placed between the sample and detector. In the first case, the successful recovery of diffraction data formed from the interrogation of powder samples with annular incident beams is presented using a coded aperture approach. In the second regime, encoding of Debye cones is shown to enable recovery of the sample position relative to the detector. The errors associated with both regimes are considered and the advantages of combining the two discussed
No difference in compensation for sugar in a drink versus sugar in semi-solid and solid foods
AbstractIt is claimed that sugar consumed in a drink is poorly compensated for by a reduction in subsequent energy intake, however very little research has tested directly the effect on appetite of adding sugar to a drink versus food. In this between subjects study, 144 participants (72 men) consumed preloads sweetened with either sucrose or the low-energy sweetener, sucralose (preload energy difference 162kcal) in the form of a blackcurrant drink, jelly or candy. The different preload viscosities were achieved by varying the amount of thickener (carrageenan) and water in the recipes. Participants completed hunger ratings before and 5, 10 and 20min after consuming their preload. After the 20-minute rating they were served a test-meal comprising an excess of bite-sized sandwiches and a sweet dessert. Energy intake measured for the same meal consumed the previous day (baseline day, no preload consumed) was used in the data analyses to control for individual differences in energy intake. Overall, there was 36% compensation for the energy difference in the preloads, but this did not vary with preload viscosity â if anything compensation was greater for the drink preload, and greater in men. The drink preload also showed an effect of sucrose versus sucralose for hunger. The lack of the predicted effect of viscosity on compensation could not be explained by differences in blood-glucose concentration 20min after the preload (measured in a separate study) or by differences in preload sweetness, flavour intensity, liking or familiarity. Comparison of baseline and test-meal food intakes indicated that, irrespective of energy content, the sweet drinks reduced the relative intake of sweet food. In conclusion, short-term energy compensation did not differ across a set of realistic drink and food stimuli
âDominant ethnicityâ and the âethnic-civicâ dichotomy in the work of A. D. Smith
This article considers the way in which the work of Anthony Smith has helped to structure debates surrounding the role of ethnicity in present-day nations. Two major lines of enquiry are evident here. First, the contemporary role of dominant ethnic groups within 'their' nations and second, the interplay between ethnic and civic elements in nationalist argument. The two processes are related, but maintain elements of distinctiveness. Smith's major contribution to the dominant ethnicity debate has been to disembed ethnicity from the ideologically-charged and/or anglo-centric discourse of ethnic relations and to place it in historical context, thereby opening up space for dominant group ethnicity to be considered as a distinct phenomenon. This said, Smith's work does not adequately account for the vicissitudes of dominant ethnicity in the contemporary West. Building on the classical works of Hans Kohn and Friedrich Meinecke, Anthony Smith has also made a seminal contribution to the debate on civic and ethnic forms of national identity and nationalist ideology. As well as freeing this debate from the strong normative overtones which it has often carried, he has continued to insist that the terms civic and ethnic should be treated as an ideal-typical distinction rather than a scheme of classification
Observation of a low-lying neutron-unbound state in 19C
Proton removal reactions from a secondary 22N beam were utilized to populate
unbound states in neutron-rich carbon isotopes. Neutrons were measured with the
Modular Neutron Array (MoNA) in coincidence with carbon fragments. A resonance
with a decay energy of 76(14) keV was observed in the system 18C+n
corresponding to a state in 19C at an excitation energy of 653(95)keV. This
resonance could correspond to the first 5/2+ state which was recently
speculated to be unbound in order to describe 1n and 2n removal cross section
measurements from 20C.Comment: accepted for publication in Nucl. Phys.
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