19 research outputs found
The elderly in the psychiatric emergency service (PES); a descriptive study
<p>Abstract</p> <p>Background</p> <p>The impact of an aging population on the psychiatric emergency service (PES) has not been fully ascertained. Cognitive dysfunctions aside, many DSM-IV disorders may have a lower prevalence in the elderly, who appear to be underrepresented in the PES. We therefore attempted to more precisely assess their patterns of PES use and their clinical and demographic characteristics.</p> <p>Methods</p> <p>Close to 30,000 visits to a general hospital PES (Montreal, Quebec, Canada) were acquired between 1990 and 2004 and pooled with over 17,000 visits acquired using the same methodology at three other services in Quebec between 2002 and 2004.</p> <p>Results</p> <p>The median age of PES patients increased over time. However, the proportion of yearly visits attributable to the elderly (compared to those under 65) showed no consistent increase during the observation period. The pattern of return visits (two to three, four to ten, eleven or more) did not differ from that of patients under 65, although the latter made a greater number of total return visits per patient. The elderly were more often women (62%), widowed (28%), came to the PES accompanied (42%) and reported « illness » as an important stressor (29%). About 39% were referred for depression or anxiety. They were less violent (10%) upon their arrival. Affective disorders predominated in the diagnostic profile, they were less co-morbid and more likely admitted than patients under 65.</p> <p>Conclusion</p> <p>Although no proportional increase in PES use over time was found the elderly do possess distinct characteristics potentially useful in PES resource planning so as to better serve this increasingly important segment of the general population.</p
O3oxidation of SO2in sea-salt aerosol water: Size distribution of non-sea-salt sulfate during the First Aerosol Characterization Experiment (ACE 1)
Non sea-salt sulfate (NSS) of 2.2-2.3 nmol m(-3) total magnitude in aerosols observed during the First Aerosol Characterization Experiment (ACE-1) at Cape Grim, Tasmania, was trimodally distributed with similar to 1 nmol NSS m(-3) in > 0.7 mu m ambient diameter (diam) coarse seasalt mode aerosols; despite this low NSS concentration, [H2SO4(g)] was so low that 0.7 mu m diam aerosols. The mechanism of O-3 oxidation of SO2 in sea-salt aerosol water (SSAW) is assessed for its capability to explain this coarse aerosol NSS. Limitation of this mechanism's NSS contribution is largely due to SSAW's buffering capacity since its reaction rate is reduced by 2 orders of magnitude at pH 6 versus the pH greater than or equal to 8 of unreacted SSAW. However, the buffering capacity of sea-salt aerosols may have been significantly enhanced over that of bulk seawater alkalinity. This appears to be due to carbonate resulting from small fragments of biogenic CaCO3 in the ocean's surface microlayer. Given the observed nonsoil calcium excess over that in bulk seawater, the estimated actual buffering capacity of sea-salt aerosols observed during ACE 1 was 50%, or more, enhanced over that due to bulk seawater alkalinity. Considering this enhanced buffering capacity, O-3 oxidation of SO2 in SSAW can produce sufficient NSS to explain 70-90% of the similar to 1 nmol m(-3) found in > 0.7 mu m diam coarse sea-salt aerosols with cloud processing and further oxidation of SO2 in SSAW (i.e., pH < 6) by other sea-salt conversion mechanisms contributing the remainder. The amount of NSS produced by sea-salt conversion mechanisms during the ACE 1 remote Southern Ocean experiment vied with homogeneous and cloud processing in their contribution to the total observed NSS of 2.2-2.3 nmol m(-3)
The SOLAS air-sea gas exchange experiment (SAGE) 2004
Author Posting. © The Author(s), 2010. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Deep Sea Research Part II: Topical Studies in Oceanography 58 (2011): 753-763, doi:10.1016/j.dsr2.2010.10.015.The SOLAS air-sea gas exchange experiment (SAGE) was a multiple-objective study investigating
gas-transfer processes and the influence of iron fertilisation on biologically driven gas exchange in
high-nitrate low-silicic acid low-chlorophyll (HNLSiLC) Sub-Antarctic waters characteristic of the
expansive Subpolar Zone of the southern oceans. This paper provides a general introduction and
summary of the main experimental findings. The release site was selected from a pre-voyage desktop
study of environmental parameters to be in the south-west Bounty Trough (46.5°S 172.5°E) to the
south-east of New Zealand and the experiment conducted between mid-March and mid-April 2004. In
common with other mesoscale iron addition experiments (FeAX’s), SAGE was designed as a
Lagrangian study quantifying key biological and physical drivers influencing the air-sea gas exchange
processes of CO2, DMS and other biogenic gases associated with an iron-induced phytoplankton
bloom. A dual tracer SF6/3He release enabled quantification of both the lateral evolution of a labelled
volume (patch) of ocean and the air-sea tracer exchange at the 10’s of km’s scale, in conjunction with
the iron fertilisation. Estimates from the dual-tracer experiment found a quadratic dependency of the
gas exchange coefficient on windspeed that is widely applicable and describes air-sea gas exchange in strong wind regimes. Within the patch, local and micrometeorological gas exchange process studies (100 m scale) and physical variables such as near-surface turbulence, temperature microstructure at the interface, wave properties, and wind speed were quantified to further assist the development of gas exchange models for high-wind environments.
There was a significant increase in the photosynthetic competence (Fv/Fm) of resident phytoplankton
within the first day following iron addition, but in contrast to other FeAX’s, rates of net primary
production and column-integrated chlorophyll a concentrations had only doubled relative to the
unfertilised surrounding waters by the end of the experiment. After 15 days and four iron additions
totalling 1.1 tonne Fe2+, this was a very modest response compared to the other mesoscale iron
enrichment experiments. An investigation of the factors limiting bloom development considered co-
limitation by light and other nutrients, the phytoplankton seed-stock and grazing regulation. Whilst
incident light levels and the initial Si:N ratio were the lowest recorded in all FeAX’s to date, there was
only a small seed-stock of diatoms (less than 1% of biomass) and the main response to iron addition
was by the picophytoplankton. A high rate of dilution of the fertilised patch relative to phytoplankton
growth rate, the greater than expected depth of the surface mixed layer and microzooplankton grazing
were all considered as factors that prevented significant biomass accumulation. In line with the limited
response, the enhanced biological draw-down of pCO2 was small and masked by a general increase in pCO2 due to mixing with higher pCO2 waters. The DMS precursor DMSP was kept in check through grazing activity and in contrast to most FeAX’s dissolved dimethylsulfide (DMS) concentration declined through the experiment. SAGE is an important low-end member in the range of responses to iron addition in FeAX’s. In the context of iron fertilisation as a geoengineering tool for atmospheric CO2 removal, SAGE has clearly demonstrated that a significant proportion of the low iron ocean may not produce a phytoplankton bloom in response to iron addition.SAGE was jointly funded through
the New Zealand Foundation for Research, Science and Technology (FRST) programs
(C01X0204) "Drivers and Mitigation of Global Change" and (C01X0223) "Ocean
Ecosystems: Their Contribution to NZ Marine Productivity." Funding was also provided for
specific collaborations by the US National Science Foundation from grants OCE-0326814
(Ward), OCE-0327779 (Ho), and OCE 0327188 OCE-0326814 (Minnett) and the UK Natural
Environment Research Council NER/B/S/2003/00282 (Archer). The New Zealand
International Science and Technology (ISAT) linkages fund provided additional funding
(Archer and Ziolkowski), and the many collaborator institutions also provided valuable
support
Recommended from our members
Shipboard measurements of dimethyl sulfide and SO 2 southwest of Tasmania during the First Aerosol Characterization Experiment (ACE 1)
Measurements of seawater dimethylsulfide (DMS), atmospheric dimethylsulfide, and sulfur dioxide (SO2) were made on board the R/VDiscoverer in the Southern Ocean, southeast of Australia, as part of the First Aerosol Characterization Experiment (ACE 1). The measurements covered a latitude range of 40°S–55°S during November-December 1995. Seawater DMS concentrations ranged from 0.4 to 6.8 nM, with a mean of 1.7±1.1 nM (1σ). The highest DMS concentrations were found in subtropical convergence zone waters north of 44°S, and the lowest were found in polar waters south of 49°S. In general, seawater DMS concentrations increased during the course of the study, presumably due to the onset of austral spring warming. Atmospheric DMS concentrations ranged from 24 to 350 parts per trillion by volume (pptv), with a mean of 112±61 pptv (1σ). Atmospheric SO2 was predominantly of marine origin with occasional anthropogenic input, as evidenced by correlation with elevated 222Rn and air mass trajectories. Concentrations ranged from 3 to 1000 pptv with a mean of 48.8± 49 pptv (1σ) and a median 15.8 pptv. The mean SO2 concentration observed in undisturbed marine air was 11.9±7.6 pptv (1σ), and the mean DMS to SO2 ratio in these conditions was 13±9 (1σ). Diurnal variations in SO2 were observed, with a daytime maximum and early morning minimum in agreement with model simulations of DMS oxidation in the marine boundary layer. Steady state calculations and photochemical box model simulations suggest that the DMS to SO2 conversion efficiency in this region is 30–50%. Comparison of these results with results from warmer regions suggests that the DMS to SO2 conversion efficiency has a positive temperature dependence
Recommended from our members
Sulfur dioxide and dimethyl sulphide in marine air at Cape Grim, Tasmania
Results from one long-term study and one summer-time field campaign in which the sulfur dioxide (SO2) mixing ratio was determined in mid-to-high latitude marine air at Cape Grim, Tasmania, are presented and analysed to provide a perspective on the potential role of SO2in the production of aerosol sulphate at this site. Sulfur dioxide at Cape Grim has a distinct seasonal cycle, with a maximum mixing ratio in summer and minimum in winter, consistent with a similar cycle observed previously at Cape Grim for dimethyl sulphide (CH3SCH3; DMS) and its other oxidation products. Concentrations of SO2 in the summer were typically 10 ppt (pmole mole−1), which is considerably lower than those found at other sites subject to marine air more equatorial in origin. A modelling study suggests that differences between equatorial and mid-to-high latitude marine SO2 concentrations result from lower levels of the DMS precursor at mid latitudes and a lower rate of SO2 production at lower temperatures. The analysis also suggests the existence of an additional non-DMS source of boundary layer sulfur, relatively more important in winter when DMS levels are low. Entrainment from the lower free troposphere appears to be one likely source
Recommended from our members
Sulfur dioxide and dimethyl sulphide in marine air at Cape Grim, Tasmania
Results from one long-term study and one summer-time field campaign in which the sulfur dioxide (SO2) mixing ratio was determined in mid-to-high latitude marine air at Cape Grim, Tasmania, are presented and analysed to provide a perspective on the potential role of SO2in the production of aerosol sulphate at this site. Sulfur dioxide at Cape Grim has a distinct seasonal cycle, with a maximum mixing ratio in summer and minimum in winter, consistent with a similar cycle observed previously at Cape Grim for dimethyl sulphide (CH3SCH3; DMS) and its other oxidation products. Concentrations of SO2 in the summer were typically 10 ppt (pmole mole−1), which is considerably lower than those found at other sites subject to marine air more equatorial in origin. A modelling study suggests that differences between equatorial and mid-to-high latitude marine SO2 concentrations result from lower levels of the DMS precursor at mid latitudes and a lower rate of SO2 production at lower temperatures. The analysis also suggests the existence of an additional non-DMS source of boundary layer sulfur, relatively more important in winter when DMS levels are low. Entrainment from the lower free troposphere appears to be one likely source
Recommended from our members
Shipboard measurements of dimethyl sulfide and SO 2 southwest of Tasmania during the First Aerosol Characterization Experiment (ACE 1)
Measurements of seawater dimethylsulfide (DMS), atmospheric dimethylsulfide, and sulfur dioxide (SO2) were made on board the R/VDiscoverer in the Southern Ocean, southeast of Australia, as part of the First Aerosol Characterization Experiment (ACE 1). The measurements covered a latitude range of 40°S–55°S during November-December 1995. Seawater DMS concentrations ranged from 0.4 to 6.8 nM, with a mean of 1.7±1.1 nM (1σ). The highest DMS concentrations were found in subtropical convergence zone waters north of 44°S, and the lowest were found in polar waters south of 49°S. In general, seawater DMS concentrations increased during the course of the study, presumably due to the onset of austral spring warming. Atmospheric DMS concentrations ranged from 24 to 350 parts per trillion by volume (pptv), with a mean of 112±61 pptv (1σ). Atmospheric SO2 was predominantly of marine origin with occasional anthropogenic input, as evidenced by correlation with elevated 222Rn and air mass trajectories. Concentrations ranged from 3 to 1000 pptv with a mean of 48.8± 49 pptv (1σ) and a median 15.8 pptv. The mean SO2 concentration observed in undisturbed marine air was 11.9±7.6 pptv (1σ), and the mean DMS to SO2 ratio in these conditions was 13±9 (1σ). Diurnal variations in SO2 were observed, with a daytime maximum and early morning minimum in agreement with model simulations of DMS oxidation in the marine boundary layer. Steady state calculations and photochemical box model simulations suggest that the DMS to SO2 conversion efficiency in this region is 30–50%. Comparison of these results with results from warmer regions suggests that the DMS to SO2 conversion efficiency has a positive temperature dependence
Biomass burning emissions of trace gases and particles in marine air at Cape Grim, Tasmania
Biomass burning (BB) plumes were measured at the Cape Grim Baseline Air
Pollution Station during the 2006 Precursors to Particles campaign, when
emissions from a fire on nearby Robbins Island impacted the station.
Measurements made included non-methane organic compounds (NMOCs) (PTR-MS),
particle number size distribution, condensation nuclei (CN)
> 3 nm, black carbon (BC) concentration, cloud condensation nuclei
(CCN) number, ozone (O<sub>3</sub>), methane (CH<sub>4</sub>), carbon monoxide
(CO), hydrogen (H<sub>2</sub>), carbon dioxide (CO<sub>2</sub>), nitrous oxide
(N<sub>2</sub>O), halocarbons and meteorology.
<br><br>
During the first plume strike event (BB1), a 4 h enhancement of CO (max
~ 2100 ppb), BC (~ 1400 ng m<sup>-3</sup>) and particles
> 3 nm (~ 13 000 cm<sup>-3</sup>) with dominant particle
mode of 120 nm were observed overnight. A wind direction change lead
to a dramatic reduction in BB tracers and a drop in the dominant particle
mode to 50 nm. The dominant mode increased in size to 80 nm
over 5 h in calm sunny conditions, accompanied by an increase in
ozone. Due to an enhancement in BC but not CO during particle growth, the
presence of BB emissions during this period could not be confirmed.
<br><br>
The ability of particles > 80 nm (CN80) to act as CCN at 0.5 %
supersaturation was investigated. The ΔCCN / ΔCN80 ratio was
lowest during the fresh BB plume (56 ± 8 %), higher during the
particle growth period (77 ± 4 %) and higher still (104 ± 3 %)
in background marine air. Particle size distributions indicate that changes
to particle chemical composition, rather than particle size, are driving
these changes. Hourly average CCN during both BB events were between 2000 and
5000 CCN cm<sup>-3</sup>, which were enhanced above typical background
levels by a factor of 6–34, highlighting the dramatic impact BB plumes can
have on CCN number in clean marine regions.
<br><br>
During the 29 h of the second plume strike event (BB2) CO, BC and a
range of NMOCs including acetonitrile and hydrogen cyanide (HCN) were clearly
enhanced and some enhancements in O<sub>3</sub> were observed
(ΔO<sub>3</sub> / ΔCO 0.001–0.074). A short-lived increase in NMOCs by
a factor of 10 corresponded with a large CO enhancement, an increase of the
NMOC / CO emission ratio (ER) by a factor of 2–4 and a halving of the
BC / CO ratio. Rainfall on Robbins Island was observed by radar during
this period which likely resulted in a lower fire combustion efficiency, and
higher emission of compounds associated with smouldering. This highlights the
importance of relatively minor meteorological events on BB emission ratios.
<br><br>
Emission factors (EFs) were derived for a range of trace gases, some never
before reported for Australian fires, (including hydrogen, phenol and
toluene) using the carbon mass balance method. This provides a unique set of
EFs for Australian coastal heathland fires. Methyl halide EFs were higher than
EFs reported from other studies in Australia and the Northern Hemisphere which
is likely due to high halogen content in vegetation on Robbins Island.
<br><br>
This work demonstrates the substantial impact that BB plumes can have on the
composition of marine air, and the significant changes that can occur as the
plume interacts with terrestrial, aged urban and marine emission sources