5,300 research outputs found

    Ground‐based measurements of NOx and total reactive oxidized nitrogen (NOy) at Sable Island, Nova Scotia, during the NARE 1993 summer intensive

    Get PDF
    Measurements of NO, NO2, and total reactive oxidized nitrogen (NOy) were added to ongoing measurements of aerosols, CO, and O3 at Sable Island (43°55â€ČN, 60°01â€ČW), Nova Scotia, during the North Atlantic Regional Experiment (NARE) 1993 summer intensive. Ambient levels of NOx and NOy were found to be highly variable, and elevated levels can be attributed to the transport of polluted continental air or presumably to relatively fresh emissions from sources upwind (e.g., ship traffic). The median values for NOx and NOy are 98 and 266 parts per trillion by volume (pptv), respectively. A multiday pollution episode occurred during which elevated NOx and NOy were observed with enhanced levels of O3, CO, and condensation nuclei. Air masses of recent tropical marine origin characterized by low and constant levels of O3 and CO were sampled after Hurricane Emily. The correlation between ozone and CO is reasonably good, although the relation is driven by the single pollution episode observed during the study. The correlation of O3 with NOy and with NOy‐NOx is complicated by the presumed NOy removal processes in the marine boundary layer. Examination of the radiosonde data and comparisons of the surface data with those obtained on the overflying aircraft provide clear indications of vertical stratification above the site

    Photochemical production and loss rates of ozone at Sable Island, Nova Scotia during the North Atlantic Regional Experiment (NARE) 1993 summer intensive

    Get PDF
    Three weeks of summertime surface‐based chemical and meteorological observations at Sable Island, Nova Scotia during the North Atlantic Regional Experiment (NARE) 1993 summer intensive are used to study instantaneous photochemical production and loss rates of ozone by means of a numerical photochemical model. Results are most sensitive to the averaging scheme of data used to constrain the model and the ambient variability of the measurements. Model simulations driven by a time series of 5 min averaged data, most representative of the chemistry at the site, yield an average net photochemical ozone production of 3.6 ppbv/d. Estimates of net ozone production designed to filter out local sources, by using 1000–1400 LT median values of observations to drive the model and by excluding short‐lived hydrocarbons, give values ranging from 1 to 4 ppbv/d. These positive values of net ozone production within the marine boundary layer over Sable Island demonstrate the impact of polluted continental plumes on the background photochemistry of the region during the intensive. The dominant ambient variables controlling photochemical production and loss rates of ozone at the site during the measurement campaign appear to be levels of nitrogen oxides, ozone, nonmethane hydrocarbons, and solar intensity determined by cloud cover. The model partitioning of nitrogen oxides agrees for the most part with measurements, lending credence to calculated photochemical production and loss rates of ozone as well as inferred levels of peroxy radicals not measured at the site. Discrepancies, however, often occur during episodes of intermittent cloud cover, fog, and rain, suggesting the influence of cloud processes on air masses reaching the site

    Can a community of practice enhance a palliative approach for people drawing close to death with dementia?

    Get PDF
    This action research study was conducted to trial a strategy intended to support a consistent, high-quality, palliative approach for people with dementia drawing close to death-the implementation of a community of practice. Professionals from community/residential care and hospitals formed this community of practice, which took on the role of an action research group. The group was supported to identify and address practice problems. Four action plans were implemented; outcomes from two are reported. When actioning the plan 'providing education and information for the staff', the staff's ratings of sessions and resources were positive but impacts upon knowledge, views, or confidence were small. When actioning 'supporting families', families providing care in non-hospital settings received information about severe dementia from suitably prepared staff, plus contact details to access support. Family feedback was primarily positive. Reference to additional practice change frameworks and inclusion of specialist palliative care professionals are recommendations for future initiatives; also focusing on targeted, achievable goals over longer timeframes

    Academic motherhood and fieldwork: Juggling time, emotions and competing demands

    Get PDF
    The idea and practice of going ‘into the field’ to conduct research and gather data is a deeply rooted aspect of Geography as a discipline. For global North Development Geographers, amongst others, this usually entails travelling to, and spending periods of time in, often far-flung parts of the global South. Forging a successful academic career as a Development Geographer in the UK, is therefore to some extent predicated on mobility. This paper aims to critically engage with the gendered aspects of this expected mobility, focusing on the challenges and time constraints that are apparent when conducting overseas fieldwork as a mother, unaccompanied by her children. The paper emphasises the emotion work that is entailed in balancing the competing demands of overseas fieldwork and mothering, and begins to think through the implications of these challenges in terms of the types of knowledge we produce, as well as in relation to gender equality within the academy

    Inertial control of the mirror suspensions of the VIRGO interferometer for gravitational wave detection

    Get PDF
    In order to achieve full detection sensitivity at low frequencies, the mirrors of interferometric gravitational wave detectors must be isolated from seismic noise. The VIRGO vibration isolator, called 'superattenuator', is fully effective at frequencies above 4 Hz. Nevertheless, the residual motion of the mirror at the mechanical resonant frequencies of the system are too large for the interferometer locking system and must be damped. A multidimensional feedback system, using inertial sensors and digital processing, has been designed for this purpose. An experimental procedure for determining the feedback control of the system has been defined. In this paper a full description of the system is given and experimental results are presented.Comment: 17 pages, 11 figures, accepted for publication on Review of Scientific Instrument

    The origin of the Narrow Line Region of Mrk 3: an overpressured jet cocoon

    Get PDF
    We have obtained HST FOC long-slit optical spectroscopy of the Narrow Line Region of the Seyfert 2 galaxy Mrk 3. In the region cospatial with the radio-jet the velocity field is highly perturbed and shows two velocity systems separated by as much as 1700 km/s. We interpret this to be the consequence of the rapid expansion of a cocoon of hot gas, shocked and heated by the radio-emitting outflow, which compresses and accelerates the ambient gas. The NLR itself is essentially a cylindrical shell expanding supersonically. From the size and velocity of the expanding region, we derive an upper limit to the radio-source age, ~ 2 E42 erg/s required to inflate the cocoon and estimate that the jet minimum advance speed is 3 E-3 pc per year. The total kinetic energy of the high velocity NLR gas can be estimated as ~6 E54 erg, comparable to the total energy carried by the jet over its lifetime and this quantitatively supports the idea that the NLR gas is accelerated by the jet. If the advance speed of Mrk 3 is representative of the Seyfert population then these sources must also be short lived and probably recurrent. The jet kinetic luminosity of Mrk 3 is between 2 and 3 orders of magnitude smaller than that derived for radio-loud AGNs with similar emission-line luminosity. On the other hand, the fraction of jet power dissipated in radio-emission is similar. We speculate that the main distinction between radio-quiet and radio-loud AGN is ascribed to a difference in jet power rather than to a different efficiency in synchrotron emission production.Comment: 13 pages, 8 figures, Astrophysical Journal in pres

    Developing and testing a strategy to enhance a palliative approach and care continuity for people who have dementia: Study overview and protocol

    Get PDF
    Background: Typically, dementia involves progressive cognitive and functional deterioration, leading to death. A palliative approach recognizes the inevitable health decline, focusing on quality of life. The approach is holistic, proactive, supports the client and the family, and can be provided by the client’s usual care team. In the last months of life, distressing symptoms, support needs, and care transitions may escalate. This project trialed a strategy intended to support a consistent, high quality, palliative approach for people with dementia drawing close to death. The strategy was to implement two communities of practice, drawn primarily from service provider organizations across care sectors, supporting them to address practice change. Communities comprised practitioners and other health professionals with a passionate commitment to dementia palliative care and the capacity to drive practice enhancement within partnering organizations. Project aims were to document: (i) changes driven by the communities of practice; (ii) changes in staff/practitioner characteristics during the study (knowledge of a palliative approach and dementia; confidence delivering palliative care; views on death and dying, palliative care, and a palliative approach for dementia); (iii) outcomes from perspectives of family carers, care providers, and community of practice members; (iv) the extent to which changes enhanced practice and care continuity; and (v) barriers to and facilitators of successful community of practice implementation. Methods/design: This action research project was implemented over 14 months in 2010/11 in metropolitan Perth, Western Australia and regional Launceston, Tasmania. Each state based community of practice worked with the researchers to scope existing practice and its outcomes. The research team compiled a report of existing practice recommendations and resources. Findings of these two steps informed community of practice action plans and development of additional resources. Change implementation was recorded and explored in interviews, comparisons being made with practice recommendations. Changes in staff/practitioner characteristics were evaluated using survey data. Findings from semi structured interviews and survey administration established outcomes from perspectives of family carers, care providers, and community of practice members. Consideration of processes and outcomes, across the two state based settings, informed identification of barriers and facilitators. Community of practice reflections also informed study recommendations

    Statistical mechanics of Fofonoff flows in an oceanic basin

    Get PDF
    We study the minimization of potential enstrophy at fixed circulation and energy in an oceanic basin with arbitrary topography. For illustration, we consider a rectangular basin and a linear topography h=by which represents either a real bottom topography or the beta-effect appropriate to oceanic situations. Our minimum enstrophy principle is motivated by different arguments of statistical mechanics reviewed in the article. It leads to steady states of the quasigeostrophic (QG) equations characterized by a linear relationship between potential vorticity q and stream function psi. For low values of the energy, we recover Fofonoff flows [J. Mar. Res. 13, 254 (1954)] that display a strong westward jet. For large values of the energy, we obtain geometry induced phase transitions between monopoles and dipoles similar to those found by Chavanis and Sommeria [J. Fluid Mech. 314, 267 (1996)] in the absence of topography. In the presence of topography, we recover and confirm the results obtained by Venaille and Bouchet [Phys. Rev. Lett. 102, 104501 (2009)] using a different formalism. In addition, we introduce relaxation equations towards minimum potential enstrophy states and perform numerical simulations to illustrate the phase transitions in a rectangular oceanic basin with linear topography (or beta-effect).Comment: 26 pages, 28 figure
    • 

    corecore