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People with cerebral palsy (CP) are less physically active than the general population and, consequently, are at increased risk of preventable disease. Evidence indicates that low-moderate doses of physical activity can reduce disease risk and improve fitness and function in people with CP. Para athletes with CP typically engage in ‘performance-focused’ sports training, which is undertaken for the sole purpose of enhancing sports performance. Anecdotally, many Para athletes report that participation in performance-focused sports training confers meaningful clinical benefits which exceed those reported in the literature; however, supporting scientific evidence is lacking. The aim of this paper is to describe the protocol for an 18-month study evaluating the clinical effects of a performance-focused swimming training programme for people with CP who have high support needs.
This study will use a concurrent multiple-baseline, single-case experimental design across three participants with CP who have high support needs. Each participant will complete a five-phase trial comprising: baseline (A1); training phase 1 (B1); maintenance phase 1 (A2); training phase 2 (B2); and maintenance phase 2 (A3). For each participant, measurement of swim velocity, health-related quality of life and gross motor functioning will be carried out a minimum of five times in each of the five phases.
The study described will produce Level II evidence regarding the effects of performance-focused swimming training on clinical outcomes in people with CP who have high support needs. Findings are expected to provide an indication of the potential for sport to augment outcomes in neurological rehabilitation.
Enteral sildenafil may be used in the intensive care unit for treatment of pulmonary arterial hypertension. We aimed to determine if initial enteral sildenafil dosing is safe in children receiving concurrent vasoactive infusions.
We performed a single-centre retrospective chart review that included patients less than 2 years of age in paediatric and cardiovascular intensive care units at an academic medical centre from 1 January, 2010 to 30 November, 2016. Included patients received concomitant enteral sildenafil and a continuously infused vasoactive agent. Exclusion criteria consisted of mechanical circulatory support, any form of dialysis, or a suspicion of septic shock at the time of sildenafil initiation. We sought to identify patients who developed worsening hemodynamic instability after initiation of enteral sildenafil defined as one or more of the following observations within 24 hours of sildenafil initiation: sildenafil discontinuation, total fluid bolus receipt >10 ml/kg, increased vasoactive support, epinephrine intravenous push administration, and/or the initiation of mechanical circulatory support.
Worsening hemodynamic instability was identified in 35% of the 130-patient cohort. Patients younger than 4 months were at increased risk of further hemodynamic instability compared with older patients (56% versus 44%, p = 0.0003) despite receiving lower median doses (1.28 mg/kg/day versus 1.78 mg/kg/day, p = 0.01).
Critically ill children receiving vasoactive infusions may be at increased risk for further hemodynamic instability after initiation of enteral sildenafil, particularly in younger patients. This population may benefit from lower starting enteral sildenafil doses of 0.25 mg/kg/dose or less every 8 hours to avoid further hemodynamic compromise.
Deep observations of the cosmic microwave background (CMB) have been made at 10 GHz with beamwidths of 5° and 8° using a triple-beam technique, which greatly reduces atmospheric effects. Significant signals are detected with an rms of ΔT/T ~ 4×10−5. These signals could be intrinsic to the CMB and are providing fundamental information about galaxy formation in the early universe. A component of this 10 GHz emission may be coming from galactic synchrotron features. This galactic contribution will be elucidated in forthcoming 15 and 30 GHz observations.
Monitoring of active late-type dwarfs, spectroscopically with high resolution (λ/Δλ ∼ 105) and high S:N (>300) round their activity cycles, principally in the Call H resonance line, offers techniques to explore (a) plage filling factors (b) 3-dimensional chromospheric velocity fields (c) maps of surface activity via “Doppler Imaging”. In this paper we deal with the use of spectral signatures to derive plage cover.
Selecting stars with previously measured or estimated rotational periods we measured Li equivalent widths in 8 stars of the Hyades late main sequence. Combining our data with literature values, we derive a homogeneous set of Li abundances. Plotting log N(Li) against Rossby number we can separate the effects of temperature and rotation. We find for stars later than F8 increased depletion with longer period, at constant surface temperature. Discounting, as improbable, spurious abundances due to surface activity effects, we give a tentative view of the implications of these results for stellar modelling.
We review briefly the observational status of abundance determinations for those elements produced in the first seconds of a “standard” Big Bang Universe, showing that although [4He] and [D] appear not to be mutually compatible there is still room for reconciliation via astration of D, for values consistent with estimated [7Li]. New limits to production cross-sections for 7Li appear to limit Nv (the number of light neutrino types) to no more than 3. Non-standard models with fluctuations are briefly considered; they are attractive because they use Ω = 1 and may also yield early C, N, O in significant quantities. The true value of 7Li [10-9 or 10−10 w.r.t. H] is the critical test here. We show where spectra of improved S:N are needed to progress in constraining cosmological models.
High resolution, high S:N spectra are used to determine the abundances of Fe, Ni, Ca, Al and Si in 25 field dwarfs with −1.2<[Fe/H]< +0.3. We find overabundances for Al, Ca and Si in stars with −1.2<[Fe/H]< −0.5 and solar [Ni/Fe] over the whole studied range.
Spectra of resolution λ/Δλ∼2 ×104 and good S:N ratio are presented in the range containing the 7Li doublet at 6707 Å for 9 main sequence or slightly evolved stars in NGC 752 (age ∼2 ×109 years). We investigate the suggested main sequence bimodality using spectroscopic indications of binarity and high rotational velocity, as well as the Li abundance to supplement previous photometry.
In this paper we have applied to the Sun a method for calibrating, in absolute flux units, Ca II H profiles of late-type stars. After comparing, in the region 3948-3882 A, an LTE synthetic spectrum with the data of the solar flux Atlas by Kurucz et al. (1984), we have defined the wavelength ranges where observations agree with computations, based on specific radiative equilibrium models and collisional broadening parameters. By fitting in these regions the spectrum of the moon observed at ESO with the corresponding synthetic spectrum, we derived a calibration factor that enables us to calibrate, in absolute flux units, the whole observed range.
High signal to noise spectra are required in chromospheric modelling because chromospheric emission lines are formed in a boundary layer under conditions of NLTE and in non-hydrostatic equilibrium, as well as in multiple magnetically-controlled streams, with horizontal structure on several scales, and vertical velocity fields. To obtain useable estimates of energy dissipation with height we have obtained sequences of spectra from F8 to K5 and for stars of different activity levels. These comprise Call H and K, the IR triplet, and MgII h and k obtained with the ESO CAT+CES or IUE. We outline the constraints such observations place on models and indicate theoretical and observational difficulties.
We have developed a new stellar population synthesis model for calculating colours and absorption line indices in early type galaxies. This model can work either for single-age stellar populations or in an evolutionary scheme following the chemical evolution. The model is based on the isochrones of the Padova group and we have developed our own method of conversion to colours. Details can be found in Vazdekis A., Casuso E., Peletier R. & Beckman J. (submitted, 1995). To test the model we have obtained accurate observations in many colours and line indices of the three standard galaxies: NGC 3379, NGC 4472 and NGC 4594.
There are two principal problems in explaining, in terms of the emission from OB stars, the ionisation of gas which emits diffuse Hα in spiral galaxies. One is the long pathlength which the ionising photons need to traverse to reach their objectives, the other is whether sufficient photons can escape from within the H II regions which surround the hot stars. Here we treat the second point, assuming that the H II regions above a certain threshold luminosity are density bounded. We calculate the escaping Lyman continuum (Lyc) fluxes from the density bounded regions in four galaxies, and show that in each of them this is easily suffcient to produce the measured diffuse Hα emission.
We have used the TAURUS Fabry–Perot mapping spectrometer on the William Herschel telescope (WHT) to produce a complete kinematic map of the disk of M100 in Hα. Here we show how the internal velocity dispersion (σ) of the principal emission components of the brightest regions varies with their Hα luminosity. The plot shows ample scatter, but an upper envelope in σ is clearly linear (in the log–log plane) with a slope of 2·6, a result which agrees precisely with an earlier graph by Arsenault et al., who selected instead the regions of highest surface brightness. We show that this result, which differs from the conventional prediction from the virial theorem, is consistent with virialisation if the H II regions are density bounded, and thus offers evidence in support of the density bounding hypothesis for the most luminous regions in disk galaxies.
We present new high quality Ha continuum-subtracted images of the grand design galaxies NGC 157, NGC 3631, NGC 6764, and NGC 6951, two of them barred and two non-barred, and describe the statistical properties of the HII regions. We have determined the positions, angular sizes and fluxes of individual HII regions, and construct luminosity functions and diameter and density distributions. We find no significant differences between arm and interarm HII region properties, or between the barred and non-barred galaxies. This paper summarizes work described in more detail by Rozas et al. (1995a,b)
High-resolution optical and NIR observations are used to constrain a dynamical model of the circumnuclear star forming (SF) region in the barred galaxy M100 (NGC 4321). Small leading arms observed in our K-band image of the nuclear region have been reproduced in numerical modeling of M100, a galaxy with a double inner Lindblad resonance (ILR). We also present preliminary optical and NIR observations of NGC 6951: a barred galaxy with circumnuclear SF showing a distinctly different behavior to M100 at 2.2µm.
We have obtained the oxygen abundance in a sample of 44 F-type dwarfs in the Ursa Major group and the Hyades open cluster, using an NLTE analysis of the O I infrared triplet at λλ 7771-7775 Å. These clusters show the “lithium gap” in the F spectral range, and it has been suggested that if this phenomenon were due to microscopic diffusion, their Li-depleted stars could also show oxygen and/or nitrogen depletion. Our results here show a substantial measure of uniformity in the oxygen abundances. The data might indicate a very small dip (< 0.1 dex) in the O abundance for stars located in the Li gap. Microscopic diffusion seems to be the only known mechanism able to produce an oxygen dip. If this mechanism were responsible for the Li gap, it would have to account for a depletion of up to two orders of magnitude in Li and, at the same time, less than 0.1 dex in oxygen. We note that turbulent mixing could modify a microscopic diffusion pattern in order to yield the observed abundances of the two elements.
We present new beryllium abundances for three unevolved stars with [Fe/H] in the range −0.4 to −1.6. The Be II doublet is detected in the three stars. A spectral synthesis analysis has been conducted to derive the abundances. We briefly discuss their Be and Li abundances, together with a wide sample of stars from the literature, in the context of mixing processes below the convection zone.
We have monitored Ca II H with a spectral resolution of 8 × 104, in asimple of late-type MS stars over a four-year period. The high resolution enables us to add information on velocity fields to the usual flux monitoring. We detect changes in wavelength of different parts of the Ca II H feature, which can be interpreted as velocity fields in the lower chromosphere, with downflow and upflow of order 0.5 km s−1, depending on the star. Flux variations in Ca II H emission can be ascribed, via velocity tagging, to long-term change in plage cover rather than short-term modulation by (incompletely sampled) rotation cycles.
We have observed seven main sequence stars in the Pleiades, with B – V between 0.98 and 1.41 (5100–3900 K), and with a wide range of rotational velocities, in Ca II H and K, Hα and have derived Li abundances. Our results, combined with literature data, indicate that the most chromospherically active stars are rapid rotators, and that at a given effective temperature the Li-rich stars show the highest chromospheric activity. A different surface coverage of active regions could influence the dichotomy observed in the Li abundance distribution.