4,140 research outputs found
FeH Absorption in the Near-Infrared Spectra of Late M and L Dwarfs
We present medium-resolution z-, J-, and H-band spectra of four late-type
dwarfs with spectral types ranging from M8 to L7.5. In an attempt to determine
the origin of numerous weak absorption features throughout their near-infrared
spectra, and motivated by the recent tentative identification of the E 4\Pi- A
^4\Pi system of FeH near 1.6 microns in umbral and cool star spectra, we have
compared the dwarf spectra to a laboratory FeH emission spectrum. We have
identified nearly 100 FeH absorption features in the z-, J-, and H-band spectra
of the dwarfs. In particular, we have identified 34 features which dominate the
appearance of the H-band spectra of the dwarfs and which appear in the
laboratory FeH spectrum. Finally, all of the features are either weaker or
absent in the spectrum of the L7.5 dwarf which is consistent with the weakening
of the known FeH bandheads in the spectra of the latest L dwarfs.Comment: accepted by Ap
Perception of first respiratory infection with Pseudomonas aeruginosa by people with cystic fibrosis and those close to them: an online qualitative study
Background: People with cystic fibrosis (CF) are susceptible to respiratory infection with Pseudomonas aeruginosa (PA), which may become chronic if initial eradication fails. Environmental acquisition and person-to-person transmission can occur. Respiratory PA infection is associated with increased mortality and more hospitalisations. This may cause patients and families anxiety and lead them to adopt preventive measures which may be ineffectual and intrusive. It is not possible to hold a conventional focus group to explore these issues because people with CF cannot meet together due to the risk of cross-infection.
Objective: To explore the perceptions of first respiratory infection with PA in people with CF and those close to them.
Design: We designed an online survey, to maximise accessibility and avoid the risk of cross-infection. This established the respondent's relationship with CF, asked 3 open questions about perceptions of PA and a final question about the prioritisation of research. Responses were analysed using a structured, iterative process. We identified keywords, analysed these incontext and derived key themes.
Setting: Promotion through social media allowed respondents from any country to participate.
Participants: People with CF and those close to them.
Results: Responses were received from 393 people, including 266 parents and 97 people with CF. The key themes were the emotional burden of PA (fear in particular); the burden of treatment PA entails and the need for accurate knowledge about PA.
Conclusions: Lack of knowledge and the health beliefs of individuals may promote fear of infection and inappropriate avoidance measures. Uncertainty about the implications of PA infection and the treatment required may cause anxiety. Healthcare professionals should provide clear information about how PA might be acquired and the treatment necessary, making clear the limitations of current understanding and acknowledging health beliefs
Effects of syntactic context on eye movements during reading
Previous research has demonstrated that properties of a currently fixated word
and of adjacent words influence eye movement control in reading. In contrast to
such local effects, little is known about the global effects on eye movement
control, for example global adjustments caused by processing difficulty of
previous sentences. In the present study, participants read text passages in
which voice (active vs. passive) and sentence structure (embedded vs.
non-embedded) were manipulated. These passages were followed by identical target
sentences. The results revealed effects of previous sentence structure on gaze
durations in the target sentence, implying that syntactic properties of
previously read sentences may lead to a global adjustment of eye movement
control
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Leadership and approaches to the management of workplace bullying
Leadership behaviour has been identified as an important antecedent of workplace bullying, since managers may prevent, permit or engage in the mistreatment of others. However, the issue of how managers respond when bullying occurs has received limited attention. With this in mind, the aim of this study was to explore how managers behave when bullying occurs in their work group, and to elucidate the contextual issues that underlie this behaviour. This was achieved through analysis of in-depth interviews with individuals involved in cases of bullying. The findings revealed a typology of four types of management behaviour in cases of bullying, each underpinned by contextual factors at the individual, group and organizational level. The study shows that the role of leadership in workplace bullying is more complex than previously thought, and suggests several ways in which managers and organizations could deal with bullying behaviour
Brood patch and sex-ratio observations indicate breeding provenance and timing in New Zealand storm petrel (Fregetta maoriana)
We used measurements of brood patch and moult status to estimate the breeding phenology of New Zealand Storm-Petrel, using birds caught at sea within the Hauraki Gulf Marine Park near Auckland, New Zealand. Birds caught OctoberâJanuary had completely downy brood patches, whereas birds caught FebruaryâApril had bare brood patches with an observed male bias in the February sex-ratio, consistent with a female pre-laying exodus typical of petrels and with the existence of an unknown colony in the region. No birds captured exhibited primary moult, which is known to occur in storm-petrels during their non-breeding season. Our data support the conclusion that the New Zealand storm-petrel breeds during JanuaryâJune in northern New Zealand and that field surveys for the species on offshore islands in this region during this period are warrante
How strongly do word reading times and lexical decision times correlate? Combining data from eye movement corpora and megastudies
We assess the amount of shared variance between three measures of visual word recognition latencies: eye movement latencies, lexical decision times and naming times. After partialling out the effects of word frequency and word length, two well-documented predictors of word recognition latencies, we see that 7-44% of the variance is uniquely shared between lexical decision times and naming times, depending on the frequency range of the words used. A similar analysis of eye movement latencies shows that the percentage of variance they uniquely share either with lexical decision times or with naming times is much lower. It is 5 â 17% for gaze durations and lexical decision times in studies with target words presented in neutral sentences, but drops to .2% for corpus studies in which eye movements to all words are analysed. Correlations between gaze durations and naming latencies are lower still. These findings suggest that processing times in isolated word processing and continuous text reading are affected by specific task demands and presentation format, and that lexical decision times and naming times are not very informative in predicting eye movement latencies in text reading once the effect of word frequency and word length are taken into account. The difference between controlled experiments and natural reading suggests that reading strategies and stimulus materials may determine the degree to which the immediacy-of-processing assumption and the eye-mind assumption apply. Fixation times are more likely to exclusively reflect the lexical processing of the currently fixated word in controlled studies with unpredictable target words rather than in natural reading of sentences or texts
Finite, diffeomorphism invariant observables in quantum gravity
Two sets of spatially diffeomorphism invariant operators are constructed in
the loop representation formulation of quantum gravity. This is done by
coupling general relativity to an anti- symmetric tensor gauge field and using
that field to pick out sets of surfaces, with boundaries, in the spatial three
manifold. The two sets of observables then measure the areas of these surfaces
and the Wilson loops for the self-dual connection around their boundaries. The
operators that represent these observables are finite and background
independent when constructed through a proper regularization procedure.
Furthermore, the spectra of the area operators are discrete so that the
possible values that one can obtain by a measurement of the area of a physical
surface in quantum gravity are valued in a discrete set that includes integral
multiples of half the Planck area. These results make possible the construction
of a correspondence between any three geometry whose curvature is small in
Planck units and a diffeomorphism invariant state of the gravitational and
matter fields. This correspondence relies on the approximation of the classical
geometry by a piecewise flat Regge manifold, which is then put in
correspondence with a diffeomorphism invariant state of the gravity-matter
system in which the matter fields specify the faces of the triangulation and
the gravitational field is in an eigenstate of the operators that measure their
areas.Comment: Latex, no figures, 30 pages, SU-GP-93/1-
Spin Networks and Quantum Gravity
We introduce a new basis on the state space of non-perturbative quantum
gravity. The states of this basis are linearly independent, are well defined in
both the loop representation and the connection representation, and are labeled
by a generalization of Penrose's spin netoworks. The new basis fully reduces
the spinor identities (SU(2) Mandelstam identities) and simplifies calculations
in non-perturbative quantum gravity. In particular, it allows a simple
expression for the exact solutions of the Hamiltonian constraint
(Wheeler-DeWitt equation) that have been discovered in the loop representation.
Since the states in this basis diagnolize operators that represent the three
geometry of space, such as the area and volumes of arbitrary surfaces and
regions, these states provide a discrete picture of quantum geometry at the
Planck scale.Comment: 42 page
Bâcatâ-Mediated Reduction of Sulfoxides to Sulfides
An efficient and operationally simple method for the reduction of sulfoxides to sulfides has been developed using bis(catecholato)diboron (Bâcatâ) as a reducing agent. The present method accommodates various functional groups which are generally prone to reduction: halides, alkynes, carbonyls, nitriles, and heterocycles are totally intact, and only sulfoxide moieties undergo reduction chemoselectively. Moreover, the remaining diboron and the resulting boronâcontaining wastes are readily removable, the practicality of this protocol being thus demonstrated
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