3,108 research outputs found

    Interactive lectures: Clickers or personal devices?

    Get PDF
    Audience response systems (‘clickers’) are frequently used to promote participation in large lecture classes, and evidence suggests that they convey a number of benefits to students, including improved academic performance and student satisfaction. The limitations of these systems (such as limited access and cost) can be overcome using students’ personal electronic devices, such as mobile phones, tablets and laptops together with text message, web- or app-based polling systems. Using questionnaires, we compare student perceptions of clicker and smartphone based polling systems. We find that students prefer interactive lectures generally, but those that used their own device preferred those lectures over lectures using clickers. However, device users were more likely to report using their devices for other purposes (checking email, social media etc.) when they were available to answer polling questions. These students did not feel that this distracted them from the lecture, instead, concerns over the use of smartphones centred around increased battery usage and inclusivity for students without access to suitable technology. Our results suggest that students generally preferred to use their own devices over clickers, and that this may be a sensible way to overcome some of the limitations associated with clickers, although issues surrounding levels of distraction and the implications for retention and recall of information need further investigation

    Impact of NHS Direct on other services: the characteristics and origins of its nurses

    Get PDF
    OBJECTIVE:: To characterise the NHS Direct nurse workforce and estimate the impact of NHS Direct on the staffing of other NHS nursing specialties. METHOD: A postal survey of NHS Direct nurses in all 17 NHS Direct call centres operating in June 2000. RESULTS: The response rate was 74% (682 of 920). In the three months immediately before joining NHS Direct, 20% (134 of 682, 95% confidence intervals 17% to 23%) of respondents had not been working in the NHS. Of the 540 who came from NHS nursing posts, one fifth had come from an accident and emergency department or minor injury unit (110 of 540), and one in seven from practice nursing (75 of 540). One in ten (65 of 681) nurses said that previous illness, injury, or disability had been an important reason for deciding to join NHS Direct. Sixty two per cent (404 of 649) of nurses felt their job satisfaction and work environment had improved since joining NHS Direct. CONCLUSION: The NHS Direct nurse workforce currently constitutes a small proportion (about 0.5%) of all qualified nurses in the NHS, although it recruits relatively experienced and well qualified nurses more heavily from some specialties, such as accident and emergency nursing, than others. However, its overall impact on staffing in any one specialty is likely to be small. NHS Direct has succeeded in providing employment for some nurses who might otherwise be unable to continue in nursing because of disability

    Identification of red supergiants in nearby galaxies with mid-IR photometry

    Full text link
    The role of episodic mass loss in massive star evolution is one of the most important open questions of current stellar evolution theory. Episodic mass loss produces dust and therefore causes evolved massive stars to be very luminous in the mid-infrared and dim at optical wavelengths. We aim to increase the number of investigated luminous mid-IR sources to shed light on the late stages of these objects. To achieve this we employed mid-IR selection criteria to identity dusty evolved massive stars in two nearby galaxies. The method is based on mid-IR colors, using 3.6 {\mu}m and 4.5 {\mu}m photometry from archival Spitzer Space Telescope images of nearby galaxies and J-band photometry from 2MASS. We applied our criteria to two nearby star-forming dwarf irregular galaxies, Sextans A and IC 1613, selecting eight targets, which we followed up with spectroscopy. Our spectral classification and analysis yielded the discovery of two M-type supergiants in IC 1613, three K-type supergiants and one candidate F-type giant in Sextans A, and two foreground M giants. We show that the proposed criteria provide an independent way for identifying dusty evolved massive stars, that can be extended to all nearby galaxies with available Spitzer/IRAC images at 3.6 {\mu}m and 4.5 {\mu}m.Comment: 8 pages, 4 figures, A&A in pres

    Controlling Decay Fungi in Douglas-Fir Heartwood with Pelletized Sodium N-Methyldithiocarbamate

    Get PDF
    A small block test was used in assessing whether pelletized sodium n-methyldithiocarbamate (NaMDC) would decompose and produce methylisothiocyanate (MITC) and thereby eliminate Antrodia carbonica colonies from Douglas-fir heartwood. Also evaluated were the effects of wood moisture content, dosage, incubation period, pH level, and presence of copper sulfate on percentage of kill of the fungus and amount of MITC in the wood. Increasing moisture content produced the most dramatic increases in MITC production and fungal control. The effects of pH and the presence of copper ions were more variable. The results indicate that pelletized NaMDC can effectively control fungal infestations in Douglas-fir heartwood. Field studies are planned

    The eccentric short-period orbit of the supergiant fast X-ray transient HD 74194 (=LM Vel)

    Get PDF
    Aims. We present the first orbital solution for the O-type supergiant star HD 74194, which is the optical counterpart of the supergiant fast X-ray transient IGR J08408-4503. Methods. We measured the radial velocities in the optical spectrum of HD 74194, and we determined the orbital solution for the first time. We also analysed the complex H{\alpha} profile. Results. HD 74194 is a binary system composed of an O-type supergiant and a compact object in a short-period (P=9.5436±0.0002P=9.5436\pm0.0002 d) and high-eccentricity (e=0.63±0.03e=0.63\pm0.03) orbit. The equivalent width of the H{\alpha} line is not modulated entirely with the orbital period, but seems to vary in a superorbital period (P=285±10P=285\pm10 d) nearly 30 times longer than the orbital one.Comment: 4 pages, 6 figures, accepted for publication in A&

    The Galactic O-Star Spectroscopic Survey (GOSSS). II. Bright Southern Stars

    Get PDF
    We present the second installment of GOSSS, a massive spectroscopic survey of Galactic O stars, based on new homogeneous, high signal-to-noise ratio, R ~ 2500 digital observations from both hemispheres selected from the Galactic O-Star Catalog (GOSC). In this paper we include bright stars and other objects drawn mostly from the first version of GOSC, all of them south of delta = -20 degrees, for a total number of 258 O stars. We also revise the northern sample of paper I to provide the full list of spectroscopically classified Galactic O stars complete to B = 8, bringing the total number of published GOSSS stars to 448. Extensive sequences of exceptional objects are given, including the early Of/WN, O Iafpe, Ofc, ON/OC, Onfp, Of?p, and Oe types, as well as double/triple-lined spectroscopic binaries. The new spectral subtype O9.2 is also discussed. The magnitude and spatial distributions of the observed sample are analyzed. We also present new results from OWN, a multi-epoch high-resolution spectroscopic survey coordinated with GOSSS that is assembling the largest sample of Galactic spectroscopic massive binaries ever attained. The OWN data combined with additional information on spectroscopic and visual binaries from the literature indicate that only a very small fraction (if any) of the stars with masses above 15-20 M_Sol are born as single systems. In the future we will publish the rest of the GOSSS survey, which is expected to include over 1000 Galactic O stars.Comment: 110 pages, 16 figures, accepted for publication in ApJS. Some figures have low quality due to arXiv file size limitations, alternative version available at http://jmaiz.iaa.es/files/Sotaetal14.pd

    Polarisation-independent Bragg gratings in ion-exchanged glass channel waveguides

    Get PDF
    The polarisation dependence of Bragg gratings photowritten in ion-exchanged glass waveguides is characterised for waveguides with different mask-opening widths and burial depths. It is found that polarisation-independent gratings can be written in waveguides with a wide variation in fabrication parameters

    Spectroscopic and photometric analysis of the early-type spectroscopic binary HD 161853 in the centre of an H II region

    Get PDF
    We study the O-type star HD 161853, which has been noted as a probable double-lined spectroscopic binary system. We secured high-resolution spectra of HD 161853 during the past nine years. We separated the two components in the system and measured their respective radial velocities for the first time. We confirm that HD 161853 is an ∼\sim1 Ma old binary system consisting of an O8 V star (MA,RV≥22M_{\rm A,RV} \geq 22 M⊙_\odot) and a B1--3 V star (MB,RV≥7.2M_{\rm B,RV} \geq 7.2 M⊙_\odot) at about 1.3 kpc. From the radial velocity curve, we measure an orbital period PP = 2.66765±\pm0.00001 d and an eccentricity ee = 0.121±\pm0.007. Its VV-band light curve is constant within 0.014 mag and does not display eclipses, from which we impose a maximum orbital inclination i=54i=54 deg. HD 161853 is probably associated with an H II region and a poorly investigated very young open cluster. In addition, we detect a compact emission region at 50 arcsec to HD 161853 in 22μ\mum-WISE and 24μ\mum-Spitzer images, which may be identified as a dust wave piled up by the radiation pressure of the massive binary system.Comment: 5 pages, 4 figures, to appear in A&
    • …
    corecore