538 research outputs found
Observations of speciated atmospheric mercury at three sites in Nevada: Evidence for a free tropospheric source of reactive gaseous mercury
Air mercury (Hg) speciation was measured for 11 weeks (June–August 2007) at three sites simultaneously in Nevada, USA. Mean reactive gaseous Hg (RGM) concentrations were elevated at all sites relative to those reported for locations not directly influenced by known point sources. RGM concentrations at all sites displayed a regular diel pattern and were positively correlated with ozone (O3) and negatively correlated with elemental Hg (Hg0) and dew point temperature (Tdp). Superimposed on the diel changes were 2- to 7-day periods when RGM concentrations increased across all three sites, producing significant intersite correlations of RGM daily means (r = 0.53–0.76, p \u3c 0.0001). During these periods, enhanced O3 concentrations and lower Tdp were also observed. Back trajectories were applied to develop gridded frequency distribution (GFD) plots and determine trajectory residence times (TRT) in specific source boxes. The GFD for the upper-quartile RGM daily means at one site showed a contributing airflow regime from the high-altitude subtropics with little precipitation, while that developed for the lower-quartile RGM concentrations indicated predominantly lower-altitude westerly flow and precipitation. Daily mean TRT in a subtropical high-altitude source box (\u3e2 km and \u3c35°N) explained a component of the daily mean RGM at two sites (r2 = 0.37 and 0.27, p\u3c0.05). These observations indicate that long-range transport of RGM from the free troposphere is a potentially important component of Hg input to rural areas of the western United States
An Updated Review of Atmospheric Mercury
The atmosphere is a key component of the biogeochemical cycle of mercury, acting as a reservoir, transport mechanism, and facilitator of chemical reactions. The chemical and physical behavior of atmospheric mercury determines how, when, and where emitted mercury pollution impacts ecosystems. In this review, we provide current information about what is known and what remains uncertain regarding mercury in the atmosphere. We discuss new ambient, laboratory, and theoretical information about the chemistry of mercury in various atmospheric media. We review what is known about mercury in and on solid- and liquid-phase aerosols. We present recent findings related to wet and dry deposition and spatial and temporal trends in atmospheric mercury concentrations. We also review atmospheric measurement methods that are in wide use and those that are currently under development
2020 Media Futures
What will our media and entertainment be like in 2020
PI in the sky: The astronaut science advisor on SLS-2
The Astronaut Science Advisor (ASA, also known as Principal-Investigator-in-a-Box) is an advanced engineering effort to apply expert systems technology to experiment monitoring and control. Its goal is to increase the scientific value of information returned from experiments on manned space missions. The first in-space test of the system will be in conjunction with Professor Larry Young's (MIT) vestibulo-ocular 'Rotating Dome' experiment on the Spacelab Life Sciences 2 mission (STS-58) in the Fall of 1993. In a cost-saving effort, off-the-shelf equipment was employed wherever possible. Several modifications were necessary in order to make the system flight-worthy. The software consists of three interlocking modules. A real-time data acquisition system digitizes and stores all experiment data and then characterizes the signals in symbolic form; a rule-based expert system uses the symbolic signal characteristics to make decisions concerning the experiment; and a highly graphic user interface requiring a minimum of user intervention presents information to the astronaut operator. Much has been learned about the design of software and user interfaces for interactive computing in space. In addition, we gained a great deal of knowledge about building relatively inexpensive hardware and software for use in space. New technologies are being assessed to make the system a much more powerful ally in future scientific research in space and on the ground
Recommended from our members
Epidemiology of Invasive Candidiasis.
Invasive candidiasis (IC) is an increasingly prevalent, costly, and potentially fatal infection brought on by the opportunistic yeast, Candida. Previously, IC has predominantly been caused by C. albicans which is often drug susceptible. There has been a global trend towards decreasing rates of infection secondary to C. albicans and a rise in non-albicans species with a corresponding increase in drug resistance creating treatment challenges. With advances in management of malignancies, there has also been an increase in the population at risk from IC along with a corresponding increase in incidence of breakthrough IC infections. Additionally, the emergence of C. auris creates many challenges in management and prevention due to drug resistance and the organisms ability to transmit rapidly in the healthcare setting. While the development of novel antifungals is encouraging for future management, understanding the changing epidemiology of IC is a vital step in future management and prevention
LSQ13ddu: a rapidly evolving stripped-envelope supernova with early circumstellar interaction signatures
This paper describes the rapidly evolving and unusual supernova LSQ13ddu, discovered by the La Silla-QUEST survey. LSQ13ddu displayed a rapid rise of just 4.8 ± 0.9 d to reach a peak brightness of −19.70 ± 0.02 mag in the LSQgr band. Early spectra of LSQ13ddu showed the presence of weak and narrow HeI features arising from interaction with circumstellar material (CSM). These interaction signatures weakened quickly, with broad features consistent with those seen in stripped-envelope SNe becoming dominant around two weeks after maximum. The narrow HeI velocities are consistent with the wind velocities of luminous blue variables but its spectra lack the typically seen hydrogen features. The fast and bright early light curve is inconsistent with radioactive ⁵⁶Ni powering but can be explained through a combination of CSM interaction and an underlying ⁵⁶Ni decay component that dominates the later time behaviour of LSQ13ddu. Based on the strength of the underlying broad features, LSQ13ddu appears deficient in He compared to standard SNe Ib
Fatal child maltreatment in England, 2005-9
Objective: This paper presents comprehensive and up-to-date data covering four years of Serious Case Reviews into fatal child maltreatment in England.
Methods: Information on all notified cases of fatal maltreatment between April 2005 and March 2009 was examined to obtain case characteristics related to a systemic classification of five broad groups of maltreatment deaths (severe physical assaults; covert homicide/infanticide; overt homicide; extreme neglect/deprivational abuse; deaths related to but not directly caused by maltreatment).
Results: A total of 276 cases was recorded giving an incidence of 0.63 cases per 100,000 children (0-17) per year. 246 cases could be classified based on the data available. Of these the commonest specific group was those children who died as a result of severe physical assaults. Apparently deliberate overt and covert homicide was less common, whilst deaths as a direct consequence of neglect were rare. In contrast, some evidence of neglect was found in at least 40% of all cases, though not the direct cause of death.
Conclusions: Class characteristics differ between the different categories of death and may suggest the need for different strategies for prevention
2020 media futures trends package
2020
Media
Futures
is
a
mul6-‐industry
strategic
foresight
project
designed
to
understand
and
envision
what
media
may
look
like
in
the
year
2020;
what
kind
of
cross-‐plaAorm
Internet
environment
may
shape
our
media
and
entertainment
in
the
coming
decade;
and
how
Ontario
firms
take
ac6on
today
toward
capturing
and
maintaining
posi6ons
of
na6onal
and
interna6onal
leadership.
The
project
asks:
In
the
face
of
sweeping
and
disrupDve
changes
driven
by
the
Internet,
how
can
we
help
companies
in
the
book,
film,
interacDve,
magazine,
music
and
television
industries
–
Ontario’s
CreaDve
and
Entertainment
Cluster
–
to
beNer
idenDfy
emerging
opportuniDes,
create
more
resilient
strategic
plans
and
partnerships,
boost
innovaDon,
and
compete
in
increasingly
demanding
global
markets?
This
document
is
a
product
of
our
‘horizon
scanning’
process.
Trends
and
Countertrends
represent
direcDonal
paNerns
in
data,
a
rising
Dde
of
signals,
in
which,
for
example,
a
criDcal
mass
of
headlines
about
people
using
Facebook
to
call
for
help
in
emergency
situaDons
points
to
a
larger
trend
regarding
the
increasing
mission-‐criDcal
importance
of
social
networks.
To
date
we
have
idenDfied
more
than
sixty
trends
at
the
project
website:
hNp://2020mediafutures.ca/Trend
- …