1,250 research outputs found
When images work faster than words: The integration of content-based image retrieval with the Northumbria Watermark Archive
Information on the manufacture, history, provenance, identification, care and conservation of paper-based artwork/objects is disparate and not always readily available. The Northumbria Watermark Archive will incorporate such material into a database, which will be made freely available on the Internet providing an invaluable resource for conservation, research and education. The efficiency of a database is highly dependant on its search mechanism. Text based mechanisms are frequently ineffective when a range of descriptive terminologies might be used i.e. when describing images or translating from foreign languages. In such cases a Content Based Image Retrieval (CBIR) system can be more effective. Watermarks provide paper with unique visual identification characteristics and have been used to provide a point of entry to the archive that is more efficient and effective than a text based search mechanism. The research carried out has the potential to be applied to any numerically large collection of images with distinctive features of colour, shape or texture i.e. coins, architectural features, picture frame profiles, hallmarks, Japanese artists stamps etc. Although the establishment of an electronic archive incorporating a CBIR system can undoubtedly improve access to large collections of images and related data, the development is rarely trouble free. This paper discusses some of the issues that must be considered i.e. collaboration between disciplines; project management; copying and digitising objects; content based image retrieval; the Northumbria Watermark Archive; the use of standardised terminology within a database as well as copyright issues
Field Measurement of Light Penetration Through Sea Ice
In connection with phytoplankton studies, a non-optical, non-electric instrument has been devised for the measurement of relative light intensity in sea-ice bore holes. When used with a sensitive photometer, absolute values for the ambient light field can be determined within and immediately under the ice. As anticipated, attenuation is greatest at the ice-air interface; values just below the ice surface were 3 to 20% of incident. Another 70 to 100 cm of ice was required to effect a further 50% decrease in illumination. Extinction values were also measured on the ice cores in the laboratory, but scattering greatly complicates the interpretation of laboratory results
The impact of uninformative parafoveal masks on L1 and late L2 speakers
Much reading research has found that informative parafoveal masks lead to a reading benefit for native speakers (see, Schotter et al., 2012). However, little reading research has tested the impact of uninformative parafoveal masks during reading. Additionally, parafoveal processing research is primarily restricted to native speakers. In the current study we manipulated the type of uninformative preview using a gaze contingent boundary paradigm with a group of L1 English speakers and a group of late L2 English speakers (L1 German). We were interested in how different types of uninformative masks impact on parafoveal processing, whether L1 and L2 speakers are similarly impacted, and whether they are sensitive to parafoveally viewed language-specific sub-lexical orthographic information. We manipulated six types of uninformative masks to test these objectives: an Identical, English pseudo-word, German pseudo-word, illegal string of letters, series of X’s, and a blank mask. We found that X masks affect reading the most with slight graded differences across the other masks, L1 and L2 speakers are impacted similarly, and neither group is sensitive to sub-lexical orthographic information. Overall these data show that not all previews are equal, and research should be aware of the way uninformative masks affect reading behavior. Additionally, we hope that future research starts to approach models of eye-movement behavior during reading from not only a monolingual but also from a multilingual perspective
Cross-linguistic differences in parafoveal semantic and orthographic processing
In this study we investigated parafoveal processing by L1 and late L2 speakers of English (L1 German) while reading in English. We hypothesized that L2ers would make use of semantic and orthographic information parafoveally. Using the gaze contingent boundary paradigm, we manipulated six parafoveal masks in a sentence (Mark found th*e wood for the fire; * indicates the invisible boundary): identical word mask (wood), English orthographic mask (wook), English string mask (zwwl), German mask (holz), German orthographic mask (holn), and German string mask (kxfs). We found an orthographic benefit for L1ers and L2ers when the mask was orthographically related to the target word (wood vs. wook) in line with previous L1 research. English L2ers did not derive a benefit (rather an interference) when a non-cognate translation mask from their L1 was used (wood vs. holz), but did derive a benefit from a German orthographic mask (wood vs. holn). While unexpected, it may be that L2ers incur a switching cost when the complete German word is presented parafoveally, and derive a benefit by keeping both lexicons active when a partial German word is presented parafoveally (narrowing down lexical candidates). To the authors’ knowledge there is no mention of parafoveal processing in any model of L2 processing/reading, and the current study provides the first evidence for a parafoveal non-cognate orthographic benefit (but only with partial orthographic overlap) in sentence reading for L2ers. We discuss how these findings fit into the framework of bilingual word recognition theories
Predicting base editing outcomes using position-specific sequence determinants.
CRISPR/Cas base editors promise nucleotide-level control over DNA sequences, but the determinants of their activity remain incompletely understood. We measured base editing frequencies in two human cell lines for two cytosine and two adenine base editors at ∼14 000 target sequences and find that base editing activity is sequence-biased, with largest effects from nucleotides flanking the target base. Whether a base is edited depends strongly on the combination of its position in the target and the preceding base, acting to widen or narrow the effective editing window. The impact of features on editing rate depends on the position, with sequence bias efficacy mainly influencing bases away from the center of the window. We use these observations to train a machine learning model to predict editing activity per position, with accuracy ranging from 0.49 to 0.72 between editors, and with better generalization across datasets than existing tools. We demonstrate the usefulness of our model by predicting the efficacy of disease mutation correcting guides, and find that most of them suffer from more unwanted editing than pure outcomes. This work unravels the position-specificity of base editing biases and allows more efficient planning of editing campaigns in experimental and therapeutic contexts
Gravitons and Lightcone Fluctuations
Gravitons in a squeezed vacuum state, the natural result of quantum creation
in the early universe or by black holes, will introduce metric fluctuations.
These metric fluctuations will introduce fluctuations of the lightcone. It is
shown that when the various two-point functions of a quantized field are
averaged over the metric fluctuations, the lightcone singularity disappears for
distinct points. The metric averaged functions remain singular in the limit of
coincident points. The metric averaged retarded Green's function for a massless
field becomes a Gaussian which is nonzero both inside and outside of the
classical lightcone. This implies some photons propagate faster than the
classical light speed, whereas others propagate slower. The possible effects of
metric fluctuations upon one-loop quantum processes are discussed and
illustrated by the calculation of the one-loop electron self-energy.Comment: 18pp, LATEX, TUTP-94-1
Nova Sagittarii 1998 (V4633 Sgr) - a permanent superhump system or an asynchronous polar?
We report the results of observations of V4633 Sgr (Nova Sagittarii 1998)
during 1998-2000. Two photometric periodicities were present in the light curve
during the three years of observations: a stable one at P=3.014 h, which is
probably the orbital period of the underlying binary system, and a second one
of lower coherence, approximately 2.5 per cent longer than the former. The
latter periodicity may be a permanent superhump, or alternatively, the spin
period of the white dwarf in a nearly synchronous magnetic system. A third
period, at P=5.06 d, corresponding to the beat between the two periods was
probably present in 1999. Our results suggest that a process of mass transfer
took place in the binary system since no later than two and a half months after
the nova eruption. We derive an interstellar reddening of E(B-V)~0.21 from our
spectroscopic measurements and published photometric data, and estimate a
distance of d~9 kpc to this nova.Comment: 13 pages, latex, 7 figures, accepted for publication in MNRA
Implementation of a PMN-PT piezocrystal-based focused array with geodesic faceted structure
The higher performance of relaxor-based piezocrystals compared with piezoceramics is now well established, notably including improved gain-bandwidth product, and these materials have been adopted widely for biomedical ultrasound imaging. However, their use in other applications, for example as a source of focused ultrasound for targeted drug delivery, is hindered in several ways. One of the issues, which we consider here, is in shaping the material into the spherical geometries used widely in focused ultrasound. Unlike isotropic unpoled piezoceramics that can be shaped into a monolithic bowl then poled through the thickness, the anisotropic structure of piezocrystals make it impossible to machine the bulk crystalline material into a bowl without sacrificing performance. Instead, we report a novel faceted array, inspired by the geodesic dome structure in architecture, which utilizes flat piezocrystal material and maximizes fill factor. Aided by 3D printing, a prototype with f# ≈ 1.2, containing 96 individually addressable elements was manufactured using 1–3 connectivity PMN-PT piezocrystal–epoxy composite. The fabrication process is presented and the array was connected to a 32-channel controller to shape and steer the beam for preliminary performance demonstration. At an operating frequency of 1 MHz, a focusing gain around 30 was achieved and the side lobe intensities were all at levels below −12 dB compared to main beam. We conclude that, by taking advantage of contemporary fabrication techniques and driving instrumentation, the geodesic array configuration is suitable for focused ultrasound devices made with piezocrystal
Telephone advice lines for adults with advanced illness and their family carers: a qualitative analysis and novel practical framework
BackgroundTelephone advice lines have been recommended internationally to support around-the-clock care for people living at home with advanced illness. While they undoubtedly support care, there is little evidence about what elements are needed for success. A national picture is needed to understand, improve and standardise service delivery/care. Aim To explore telephone advice lines for people living at home with advanced illness across the four UK nations, and to construct a practical framework to improve services.DesignA cross-national evaluation of telephone advice lines using structured qualitative interviews. A patient and public involvement workshop was conducted to refine the framework.Setting/participantsProfessionals with responsibilities for how palliative care services are delivered and/or funded at a local or regional level, were purposively sampled. ResultsSeventy-one interviews were conducted, covering 60 geographical areas. Five themes were identified. Availability: Ten advice line models were described. Variation led to confusion about who to call and when. Accessibility, awareness and promotion: It was assumed that patients/carers know who to call out-of-hours, but often they did not. Practicalities: Call handlers skills/expertise varied, which influenced how calls were managed. Possible responses ranged from signposting to organising home visits. Integration/continuity of care: Integration between care providers was limited by electronic medical records access/information sharing. Service structure/commissioning: Sustained funding was often an issue for charitably funded organisations.ConclusionsOur novel evidence-based practical framework could be transformative for service design/delivery, as it presents key considerations relating to the various elements of advice lines that may impact on the patient/carer experience
Can inflationary models of cosmic perturbations evade the secondary oscillation test?
We consider the consequences of an observed Cosmic Microwave Background (CMB)
temperature anisotropy spectrum containing no secondary oscillations. While
such a spectrum is generally considered to be a robust signature of active
structure formation, we show that such a spectrum {\em can} be produced by
(very unusual) inflationary models or other passive evolution models. However,
we show that for all these passive models the characteristic oscillations would
show up in other observable spectra. Our work shows that when CMB polarization
and matter power spectra are taken into account secondary oscillations are
indeed a signature of even these very exotic passive models. We construct a
measure of the observability of secondary oscillations in a given experiment,
and show that even with foregrounds both the MAP and \pk satellites should be
able to distinguish between models with and without oscillations. Thus we
conclude that inflationary and other passive models can {\em not} evade the
secondary oscillation test.Comment: Final version accepted for publication in PRD. Minor improvements
have been made to the discussion and new data has been included. The
conclusions are unchagne
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