740 research outputs found

    History of the Pinus sylvestris treeline at Creag Fhiaclach, Inverness-shire

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    Traffic-related air pollution and obesity formation in children: a longitudinal, multilevel analysis.

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    BackgroundBiologically plausible mechanisms link traffic-related air pollution to metabolic disorders and potentially to obesity. Here we sought to determine whether traffic density and traffic-related air pollution were positively associated with growth in body mass index (BMI = kg/m2) in children aged 5-11 years.MethodsParticipants were drawn from a prospective cohort of children who lived in 13 communities across Southern California (N = 4550). Children were enrolled while attending kindergarten and first grade and followed for 4 years, with height and weight measured annually. Dispersion models were used to estimate exposure to traffic-related air pollution. Multilevel models were used to estimate and test traffic density and traffic pollution related to BMI growth. Data were collected between 2002-2010 and analyzed in 2011-12.ResultsTraffic pollution was positively associated with growth in BMI and was robust to adjustment for many confounders. The effect size in the adjusted model indicated about a 13.6% increase in annual BMI growth when comparing the lowest to the highest tenth percentile of air pollution exposure, which resulted in an increase of nearly 0.4 BMI units on attained BMI at age 10. Traffic density also had a positive association with BMI growth, but this effect was less robust in multivariate models.ConclusionsTraffic pollution was positively associated with growth in BMI in children aged 5-11 years. Traffic pollution may be controlled via emission restrictions; changes in land use that promote jobs-housing balance and use of public transit and hence reduce vehicle miles traveled; promotion of zero emissions vehicles; transit and car-sharing programs; or by limiting high pollution traffic, such as diesel trucks, from residential areas or places where children play outdoors, such as schools and parks. These measures may have beneficial effects in terms of reduced obesity formation in children

    The MASSIVE Survey - VII. The Relationship of Angular Momentum, Stellar Mass and Environment of Early-Type Galaxies

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    We analyse the environmental properties of 370 local early-type galaxies (ETGs) in the MASSIVE and ATLAS3D surveys, two complementary volume-limited integral-field spectroscopic (IFS) galaxy surveys spanning absolute KK-band magnitude −21.5>MK>−26.6-21.5 > M_K > -26.6, or stellar mass 8×109<M∗<2×1012M⊙8 \times 10^{9} < M_* < 2 \times 10^{12} M_\odot. We find these galaxies to reside in a diverse range of environments measured by four methods: group membership (whether a galaxy is a brightest group/cluster galaxy, satellite, or isolated), halo mass, large-scale mass density (measured over a few Mpc), and local mass density (measured within the NNth neighbour). The spatially resolved IFS stellar kinematics provide robust measurements of the spin parameter λe\lambda_e and enable us to examine the relationship among λe\lambda_e, M∗M_*, and galaxy environment. We find a strong correlation between λe\lambda_e and M∗M_*, where the average λe\lambda_e decreases from ∌0.4\sim 0.4 to below 0.1 with increasing mass, and the fraction of slow rotators fslowf_{\rm slow} increases from ∌10\sim 10% to 90%. We show for the first time that at fixed M∗M_*, there are almost no trends between galaxy spin and environment; the apparent kinematic morphology-density relation for ETGs is therefore primarily driven by M∗M_* and is accounted for by the joint correlations between M∗M_* and spin, and between M∗M_* and environment. A possible exception is that the increased fslowf_{\rm slow} at high local density is slightly more than expected based only on these joint correlations. Our results suggest that the physical processes responsible for building up the present-day stellar masses of massive galaxies are also very efficient at reducing their spin, in any environment.Comment: Accepted to MNRA

    Incidence of WISE -selected obscured AGNs in major mergers and interactions from the SDSS

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    We use the Wide-field Infrared Survey Explorer (WISE) and the Sloan Digital Sky Survey (SDSS) to confirm a connection between dust-obscured active galactic nuclei (AGNs) and galaxy merging. Using a new, volume-limited (z ≀ 0.08) catalogue of visually selected major mergers and galaxy–galaxy interactions from the SDSS, with stellar masses above 2 × 1010 M⊙, we find that major mergers (interactions) are 5–17 (3–5) times more likely to have red [3.4] − [4.6] colours associated with dust-obscured or ‘dusty’ AGNs, compared to non-merging galaxies with similar masses. Using published fibre spectral diagnostics, we map the [3.4] − [4.6] versus [4.6] − [12] colours of different emission-line galaxies and find that one-quarter of Seyferts have colours indicative of a dusty AGN. We find that AGNs are five times more likely to be obscured when hosted by a merging galaxy, half of AGNs hosted by a merger are dusty, and we find no enhanced frequency of optical AGNs in merging over non-merging galaxies. We conclude that undetected AGNs missed at shorter wavelengths are at the heart of the ongoing AGN-merger connection debate. The vast majority of mergers hosting dusty AGNs are star forming and located at the centres of Mhalo < 1013 M⊙ groups. Assuming plausibly short-duration dusty-AGN phases, we speculate that a large fraction of gas-rich mergers experience a brief obscured AGN phase, in agreement with the strong connection between central star formation and black hole growth seen in merger simulations

    Incidence of WISE -selected obscured AGNs in major mergers and interactions from the SDSS

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    We use the Wide-field Infrared Survey Explorer (WISE) and the Sloan Digital Sky Survey (SDSS) to confirm a connection between dust-obscured active galactic nuclei (AGNs) and galaxy merging. Using a new, volume-limited (z ≀ 0.08) catalogue of visually selected major mergers and galaxy–galaxy interactions from the SDSS, with stellar masses above 2 × 1010 M⊙, we find that major mergers (interactions) are 5–17 (3–5) times more likely to have red [3.4] − [4.6] colours associated with dust-obscured or ‘dusty’ AGNs, compared to non-merging galaxies with similar masses. Using published fibre spectral diagnostics, we map the [3.4] − [4.6] versus [4.6] − [12] colours of different emission-line galaxies and find that one-quarter of Seyferts have colours indicative of a dusty AGN. We find that AGNs are five times more likely to be obscured when hosted by a merging galaxy, half of AGNs hosted by a merger are dusty, and we find no enhanced frequency of optical AGNs in merging over non-merging galaxies. We conclude that undetected AGNs missed at shorter wavelengths are at the heart of the ongoing AGN-merger connection debate. The vast majority of mergers hosting dusty AGNs are star forming and located at the centres of Mhalo < 1013 M⊙ groups. Assuming plausibly short-duration dusty-AGN phases, we speculate that a large fraction of gas-rich mergers experience a brief obscured AGN phase, in agreement with the strong connection between central star formation and black hole growth seen in merger simulations

    Définir les compétences procédurales essentielles dans la formation médicale canadienne de premier cycle

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    Introduction: We conducted a national survey to characterize current Canadian procedural skills training in Undergraduate Medical Education (UGME). The goals were to identify the most important procedures students should know upon graduation and assess clinician-educator perceptions regarding implementation of a pre-clerkship procedural program. Methods: We distributed the survey to physician-educators across Canada’s 17 medical schools. Respondents were directed to an individualized survey that collected demographic data, physician-educator responses on essential procedural skills, as well as physician-educator opinions on the value of a pre-clerkship procedural training program. Results: The response rate for this survey was 21% (42 out of 201 distributed surveys were completed). The top 10 most important procedures identified by physician-educators included IV Access, Airway Management, Local anesthesia/field block, Casting, Spontaneous Vaginal Delivery, Testing for STIs, Phlebotomy, Suturing of Lacerations, Nasogastric Tube Insertion, and Venipuncture. Physician-educators supported a pre-clerkship procedural program. Conclusions: Identifying the most crucial procedural skills is the first step in implementing a competency-based procedural skills training program for Canadian medical students. With the list of essential skills, and the support for physician-educators in developing a pre-clerkship procedural skills curriculum, hopefully there can be future development of formalized curricula.Contexte: Nous avons menĂ© un sondage Ă  l’échelle nationale pour caractĂ©riser les compĂ©tences procĂ©durales canadiennes dans la formation mĂ©dicale de premier cycle. L’objectif Ă©tait de reconnaĂźtre les plus importantes procĂ©dures que les Ă©tudiants devaient connaĂźtre Ă  la fin de leur formation et d’évaluer les perceptions des cliniciens Ă©ducateurs au sujet de la mise en Ɠuvre de leur programme procĂ©dural avant les stages. MĂ©thodes&nbsp;: Nous avons distribuĂ© le sondage Ă  des mĂ©decins Ă©ducateurs dans les 17 Ă©coles de mĂ©decine du Canada. Les rĂ©pondants ont Ă©tĂ© dirigĂ©s vers un sondage individualisĂ© qui recueillait les donnĂ©es dĂ©mographiques, les rĂ©ponses des mĂ©decins Ă©ducateurs sur les compĂ©tences procĂ©durales essentielles, ainsi que les opinions des mĂ©decins Ă©ducateurs sur la valeur du programme de formation procĂ©durale avant les stages. RĂ©sultats&nbsp;: Le taux de rĂ©ponse Ă  ce sondage a Ă©tĂ© de 21&nbsp;% (42 des 201 sondages distribuĂ©s ont Ă©tĂ© remplis). Les dix plus importantes procĂ©dures recensĂ©es par les mĂ©decins Ă©ducateurs comprenaient l’accĂšs IV, l’assistance respiratoire, le bloc anesthĂ©sie locale/champ, le moulage de plĂątre, l’accouchement spontanĂ© par voie vaginale, les tests d’ITS, la phlĂ©botomie, la suture des lacĂ©rations, l’insertion d’une sonde nasogastrique et la ponction veineuse. Les mĂ©decins Ă©ducateurs soutenaient un programme procĂ©dural avant les stages. Conclusions&nbsp;: Établir les compĂ©tences procĂ©durales les plus essentielles reprĂ©sente la premiĂšre Ă©tape dans la mise en Ɠuvre d’un programme de formation dans les compĂ©tences procĂ©durales fondĂ© sur les compĂ©tences pour les Ă©tudiants canadiens en mĂ©decine. Avec la liste de compĂ©tences essentielles et le soutien des mĂ©decins Ă©ducateurs dans le dĂ©veloppement d’un programme de compĂ©tences procĂ©durales avant les stages, nous espĂ©rons qu’un programme structurĂ© sera Ă©laborĂ©
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