1,188 research outputs found
Post-glacial valley evolution and post-disturbance channel response as a context for restoration, upper Colorado River, Rocky Mountain National Park
Department Head: Sally J. Sutton.2010 Summer.Includes bibliographical references (pages 97-101).In 2003 a human-caused debris flow initiated by a breach in Grand Ditch in Rocky Mountain National Park delivered ~36,000 m3 of sediment into the Colorado River. The debris flow deposited up to ~1 m of sediment in the Lulu City wetland and major reworking of the Colorado River channel also occurred. The objectives of this study are to determine 1) how the 2003 deposit in Lulu City wetland relates to the historic range of variability in rates and processes of aggradation during the Holocene; and 2) if recovery of channel forms and processes has occurred in the Colorado River during the six years following 2003. Ground penetrating radar surveys, soil descriptions, and radiocarbon dating were used to quantify rates and processes of fill in Lulu City wetland. Channel recovery was assessed by comparing sediment transport rating curves to reference sites, monitoring changes in channel geometry, and quantifying bed material gradation. Results indicate that aggradation rates in Lulu City wetland varied through the late Holocene at periods correlated with distinct climates, and have increased approximately sixfold during the past 1-2 centuries of anthropogenic influence. Results from the Colorado River indicate channel forms and processes recovered between 2003 and 2009. Bed armoring and removal of fine sediments occurred, and channel stability persisted from 2003-2009. Results from the Lulu City wetland and impacted Colorado River can be used to guide effective restoration following the 2003 debris flow
Mobile metal adatoms on single layer, bilayer and trilayer graphene: an ab initio study correlated with experimental electron microscopy data
The plane-wave density functional theory code CASTEP was used with the Tkatchenko-Scheffler van der Waals correction scheme and the generalized gradient approximation of Perdew, Burke, and Ernzerhof (GGA PBE) to calculate the binding energy of Au, Cr, and Al atoms on the armchair and zigzag edge binding sites of monolayer graphene, and at the high-symmetry adsorption sites of single layer, bilayer, and trilayer graphene. All edge site binding energies were found to be substantially higher than the adsorption energies for all metals. The adatom migration activation barriers for the lowest energy migration paths on pristine monolayer, bilayer, and trilayer graphene were then calculated and found to be smaller than or within an order of magnitude of kBT at room temperature, implying very high mobility for all adatoms studied. This suggests that metal atoms evaporated onto graphene samples quickly migrate across the lattice and bind to the energetically favorable edge sites before being characterized in the microscope. We then prove this notion for Al and Au on graphene with scanning transmission electron microscopy (STEM) images showing that these atoms are observed exclusively at edge sites, and also hydrocarbon-contaminated regions, where the pristine regions of the lattice are completely devoid of adatoms. Additionally, we review the issue of fixing selected atomic positions during geometry optimization calculations for graphene/adatom systems and suggest a guiding principle for future studies
Root Cause Identification for Collective Anomalies in Time Series given an Acyclic Summary Causal Graph with Loops
This paper presents an approach for identifying the root causes of collective
anomalies given observational time series and an acyclic summary causal graph
which depicts an abstraction of causal relations present in a dynamic system at
its normal regime. The paper first shows how the problem of root cause
identification can be divided into many independent subproblems by grouping
related anomalies using d-separation. Further, it shows how, under this
setting, some root causes can be found directly from the graph and from the
time of appearance of anomalies. Finally, it shows, how the rest of the root
causes can be found by comparing direct effects in the normal and in the
anomalous regime. To this end, an adjustment set for identifying direct effects
is introduced. Extensive experiments conducted on both simulated and real-world
datasets demonstrate the effectiveness of the proposed method.Comment: Proceedings of the 26th International Conference on Artificial
Intelligence and Statistics (AISTATS) 2023, Valencia, Spai
Case Studies of Causal Discovery from IT Monitoring Time Series
Information technology (IT) systems are vital for modern businesses, handling
data storage, communication, and process automation. Monitoring these systems
is crucial for their proper functioning and efficiency, as it allows collecting
extensive observational time series data for analysis. The interest in causal
discovery is growing in IT monitoring systems as knowing causal relations
between different components of the IT system helps in reducing downtime,
enhancing system performance and identifying root causes of anomalies and
incidents. It also allows proactive prediction of future issues through
historical data analysis. Despite its potential benefits, applying causal
discovery algorithms on IT monitoring data poses challenges, due to the
complexity of the data. For instance, IT monitoring data often contains
misaligned time series, sleeping time series, timestamp errors and missing
values. This paper presents case studies on applying causal discovery
algorithms to different IT monitoring datasets, highlighting benefits and
ongoing challenges.Comment: Accepted to the UAI 2023 Workshop on The History and Development of
Search Methods for Causal Structur
Determinants of Mortality in Children under Five Years of Age with Severe Acute Malnutrition Admitted to the Yalgado Ouédraogo Teaching Hospital (Burkina Faso)
Background: To determine critical factors associated with severely malnourished children under five this case-control study was conducted.
Methods: The data of a total of 433 children aged 0-59 months and admitted to the Hospital Yalgado Ouedraogo, (CHU â YO) between January 31, 2009 to January 31, 2013, were included in the analysis: 72 for the case group and 361 for the control group. Clinical and treatment records were accessed and data were analyzed.
Results: For clinical signs, determinants of mortality were diarrhea [OR = 4.6; (95%CI 2.6-8.2], anorexia [OR = 2.7; (95%CI 1.4-5.0] and hepatomegaly [OR = 2.6; (95%CI 1.4-4.8]. For infections, determinants of mortality were pediatric HIV/AIDS [OR = 10.9; (95%CI 5.6-21.5] and digestive illnesses [OR = 5.1 (95%CI 2.8-9.4)]. Regarding the complications of malnutrition, determinants of mortality were severe dehydration [OR = 16.4 (95%CI 8.0-33.5)], skin lesions [OR = 14.3 (95%CI 6.4 -31.9)], heart failure [OR = 6.8 (95%CI 2.5-19.0)] and severe anemia [OR = 3.2(95%CI 1.4-7.1)]. For biochemical indicators, low serum sodium [OR = 0.7(95%CI 0.5-1.0)] and potassium levels [OR = 0.9(95%CI 0.9-1.0)] were the critical factors. In addition the risk of death was associated with low value of MUAC [OR = 0.9 (95% CI 0.8-0.9)].
Conclusions: The risk of death of children with severe acute malnutrition varies according to different factors studied
Graphene as a transparent conductive support for studying biological molecules by transmission electron microscopy
We demonstrate the application of graphene as a support for imaging
individual biological molecules in transmission electron microscope (TEM). A
simple procedure to produce free-standing graphene membranes has been designed.
Such membranes are extremely robust and can support practically any
sub-micrometer object. Tobacco mosaic virus has been deposited on graphene
samples and observed in a TEM. High contrast has been achieved even though no
staining has been applied
Atomically Resolved Imaging of Highly Ordered Alternating Fluorinated Graphene
One of the most desirable goals of graphene research is to produce ordered 2D
chemical derivatives of suitable quality for monolayer device fabrication. Here
we reveal, by focal series exit wave reconstruction, that C2F chair is a stable
graphene derivative and demonstrates pristine long-range order limited only by
the size of a functionalized domain. Focal series of images of graphene and C2F
chair formed by reaction with XeF2 were obtained at 80 kV in an
aberration-corrected transmission electron microscope. EWR images reveal that
single carbon atoms and carbon-fluorine pairs in C2F chair alternate strictly
over domain sizes of at least 150 nm^2 with electron diffraction indicating
ordered domains >/= 0.16 square micrometer. Our results also indicate that,
within an ordered domain, functionalization occurs on one side only as theory
predicts. Additionally we show that electron diffraction provides a quick and
easy method for distinguishing between graphene, C2F chair and fully
fluorinated stoichiometric CF 2D phases
Graphene re-knits its holes
Nano-holes, etched under an electron beam at room temperature in singlelayer
graphene sheets as a result of their interaction with metalimpurities, are
shown to heal spontaneously by filling up with either non-hexagon,
graphene-like, or perfect hexagon 2D structures. Scanning transmission electron
microscopy was employed to capture the healing process and study atom-by-atom
the re-grown structure. A combination of these nano-scale etching and
re-knitting processes could lead to new graphene tailoring approaches.Comment: 11 pages, 4 figure
2020 media futures trends package
2020
Media
Futures
is
a
mul6-Ââindustry
strategic
foresight
project
designed
to
understand
and
envision
what
media
may
look
like
in
the
year
2020;
what
kind
of
cross-ÂâplaAorm
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
â
Ontarioâs
CreaDve
and
Entertainment
Cluster
â
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
âhorizon
scanningâ
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-ÂâcriDcal
importance
of
social
networks.
To
date
we
have
idenDfied
more
than
sixty
trends
at
the
project
website:
hNp://2020mediafutures.ca/Trend
a cross-cultural comparison between Portugal and the United States
Background: Motor competence and health-related fitness are important components for the development and maintenance of a healthy lifestyle in children. This study examined cross-cultural performances on motor competence and health-related fitness between Portuguese and U.S. children.
Methods: Portuguese (n = 508; 10.14 +/- 2.13 years , mean +/- SD) and U.S. (n = 710; 9.48 +/- 1.62 years) children performed tests of cardiorespiratory fitness (Progressive Aerobic Cardiovascular Endurance Run), upper body strength (handgrip), locomotor skill performance (standing long jump), and object projection skill performance (throwing and kicking). Portuguese and U.S. children were divided into 2 age groups (6=9 and 10=13 years) for data analysis purposes. A two=factor one=way analysis of covariance (ANOVA) was conducted with the Progressive Aerobic Cardiovascular Endur ance Run, handgrip, standing long jump scores, kicking, and throwing speed (km/h) as dependent variables.
Results: Results indicated that Portuguese children, irrespective of sex, presented better performances in locomotor and cardiorespiratory performance (standing long jump and Progressive Aerobic Cardiovascular Endurance Run) than U.S. children in both age bands. U.S. children outper formed Portuguese children during throwing and handgrip tests. Kicking tests presented gender differences: Portuguese boys and U.S. girls
outperformed their internationally matched counterparts.
Conclusion: Cultural differences in physical education curricula and sports participation may impact differences in motor competence and fitness development in these countries.4811-99FE-2ECD | Luis Paulo RodriguesN/
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