104 research outputs found
The World Trade Center 1993 Attack vs. Osama Bin-Laden’s Fatwa as Causes of the September 11, 2001 Terror Attack
It is important to study the causes of the September 11 attacks because knowing the root cause of a problem is the best way to fix it. In this study, I will research the question: Was the 1993 World Trade Center bombing more or less of a cause of the September 11, 2001 attacks than Osama Bin-Laden’s fatwa, issued in 1998? I will be using the case study method to conduct this research by looking at previous research done on both topics and coming to a conclusion as to which event was a more major cause. This study is going to help researchers uncover the extent to which both the World Trade Center bombing of 1993 and Osama Bin-Laden\u27s fatwa caused al-Qaeda to want to attack the United States on September 11, 2001 and it will also give researchers a better idea of how jihad and Sharia law play a role in terrorism
Predicting later categories of upper limb activity from earlier clinical assessments following stroke: An exploratory analysis
BACKGROUND: Accelerometers allow for direct measurement of upper limb (UL) activity. Recently, multi-dimensional categories of UL performance have been formed to provide a more complete measure of UL use in daily life. Prediction of motor outcomes after stroke have tremendous clinical utility and a next step is to explore what factors might predict someone\u27s subsequent UL performance category.
PURPOSE: To explore how different machine learning techniques can be used to understand how clinical measures and participant demographics captured early after stroke are associated with the subsequent UL performance categories.
METHODS: This study analyzed data from two time points from a previous cohort (n = 54). Data used was participant characteristics and clinical measures from early after stroke and a previously established category of UL performance at a later post stroke time point. Different machine learning techniques (a single decision tree, bagged trees, and random forests) were used to build predictive models with different input variables. Model performance was quantified with the explanatory power (in-sample accuracy), predictive power (out-of-bag estimate of error), and variable importance.
RESULTS: A total of seven models were built, including one single decision tree, three bagged trees, and three random forests. Measures of UL impairment and capacity were the most important predictors of the subsequent UL performance category, regardless of the machine learning algorithm used. Other non-motor clinical measures emerged as key predictors, while participant demographics predictors (with the exception of age) were generally less important across the models. Models built with the bagging algorithms outperformed the single decision tree for in-sample accuracy (26-30% better classification) but had only modest cross-validation accuracy (48-55% out of bag classification).
CONCLUSIONS: UL clinical measures were the most important predictors of the subsequent UL performance category in this exploratory analysis regardless of the machine learning algorithm used. Interestingly, cognitive and affective measures emerged as important predictors when the number of input variables was expanded. These results reinforce that UL performance, in vivo, is not a simple product of body functions nor the capacity for movement, instead being a complex phenomenon dependent on many physiological and psychological factors. Utilizing machine learning, this exploratory analysis is a productive step toward the prediction of UL performance. Trial registration NA
The Metal-Enriched Outer Disk of NGC 2915
We present optical emission-line spectra for outlying HII regions in the
extended neutral gas disk surrounding the blue compact dwarf galaxy NGC 2915.
Using a combination of strong-line R23 and direct oxygen abundance
measurements, we report a flat, possibly increasing, metallicity gradient out
to 1.2 times the Holmberg radius. We find the outer-disk of NGC 2915 to be
enriched to a metallicity of 0.4 Z_solar. An analysis of the metal yields shows
that the outer disk of NGC 2915 is overabundant for its gas fraction, while the
central star-foming core is similarly under-abundant for its gas fraction. Star
formation rates derived from very deep ~14 ks GALEX FUV exposures indicate that
the low-level of star formation observed at large radii is not sufficient to
have produced the measured oxygen abundances at these galactocentric distances.
We consider 3 plausible mechanisms that may explain the metal-enriched outer
gaseous disk of NGC 2915: radial redistribution of centrally generated metals,
strong galactic winds with subsequent fallback, and galaxy accretion. Our
results have implications for the physical origin of the mass-metallicity
relation for gas-rich dwarf galaxies.Comment: 11 pages, 4 figures, accepted to ApJ April 8th, 201
Implementation of wearable sensing technology for movement: Pushing forward into the routine physical rehabilitation care field
While the promise of wearable sensor technology to transform physical rehabilitation has been around for a number of years, the reality is that wearable sensor technology for the measurement of human movement has remained largely confined to rehabilitation research labs with limited ventures into clinical practice. The purposes of this paper are to: (1) discuss the major barriers in clinical practice and available wearable sensing technology; (2) propose benchmarks for wearable device systems that would make it feasible to implement them in clinical practice across the world and (3) evaluate a current wearable device system against the benchmarks as an example. If we can overcome the barriers and achieve the benchmarks collectively, the field of rehabilitation will move forward towards better movement interventions that produce improved function not just in the clinic or lab, but out in peoples\u27 homes and communities
The SAMI Galaxy Survey: Shocks and Outflows in a normal star-forming galaxy
We demonstrate the feasibility and potential of using large integral field
spectroscopic surveys to investigate the prevalence of galactic-scale outflows
in the local Universe. Using integral field data from SAMI and the Wide Field
Spectrograph, we study the nature of an isolated disk galaxy, SDSS
J090005.05+000446.7 (z = 0.05386). In the integral field datasets, the galaxy
presents skewed line profiles changing with position in the galaxy. The skewed
line profiles are caused by different kinematic components overlapping in the
line-of-sight direction. We perform spectral decomposition to separate the line
profiles in each spatial pixel as combinations of (1) a narrow kinematic
component consistent with HII regions, (2) a broad kinematic component
consistent with shock excitation, and (3) an intermediate component consistent
with shock excitation and photoionisation mixing. The three kinematic
components have distinctly different velocity fields, velocity dispersions,
line ratios, and electron densities. We model the line ratios, velocity
dispersions, and electron densities with our MAPPINGS IV shock and
photoionisation models, and we reach remarkable agreement between the data and
the models. The models demonstrate that the different emission line properties
are caused by major galactic outflows that introduce shock excitation in
addition to photoionisation by star-forming activities. Interstellar shocks
embedded in the outflows shock-excite and compress the gas, causing the
elevated line ratios, velocity dispersions, and electron densities observed in
the broad kinematic component. We argue from energy considerations that, with
the lack of a powerful active galactic nucleus, the outflows are likely to be
driven by starburst activities. Our results set a benchmark of the type of
analysis that can be achieved by the SAMI Galaxy Survey on large numbers of
galaxies.Comment: 17 pages, 15 figures. Accepted to MNRAS. References update
GNOSIS: the first instrument to use fibre Bragg gratings for OH suppression
GNOSIS is a prototype astrophotonic instrument that utilizes OH suppression
fibres consisting of fibre Bragg gratings and photonic lanterns to suppress the
103 brightest atmospheric emission doublets between 1.47-1.7 microns. GNOSIS
was commissioned at the 3.9-meter Anglo-Australian Telescope with the IRIS2
spectrograph to demonstrate the potential of OH suppression fibres, but may be
potentially used with any telescope and spectrograph combination. Unlike
previous atmospheric suppression techniques GNOSIS suppresses the lines before
dispersion and in a manner that depends purely on wavelength. We present the
instrument design and report the results of laboratory and on-sky tests from
commissioning. While these tests demonstrated high throughput and excellent
suppression of the skylines by the OH suppression fibres, surprisingly GNOSIS
produced no significant reduction in the interline background and the
sensitivity of GNOSIS and IRIS2 is about the same as IRIS2. It is unclear
whether the lack of reduction in the interline background is due to physical
sources or systematic errors as the observations are detector noise-dominated.
OH suppression fibres could potentially impact ground-based astronomy at the
level of adaptive optics or greater. However, until a clear reduction in the
interline background and the corresponding increasing in sensitivity is
demonstrated optimized OH suppression fibres paired with a fibre-fed
spectrograph will at least provide a real benefits at low resolving powers.Comment: 15 pages, 13 figures, accepted to A
GAMA/DEVILS: Cosmic star formation and AGN activity over 12.5 billion years
We use the Galaxy and Mass Assembly (GAMA) and the Deep Extragalactic Visible
Legacy Survey (DEVILS) observational data sets to calculate the cosmic star
formation rate (SFR) and active galactic nuclei (AGN) bolometric luminosity
history (CSFH/CAGNH) over the last 12.5 billion years. SFRs and AGN bolometric
luminosities were derived using the spectral energy distribution fitting code
ProSpect, which includes an AGN prescription to self consistently model the
contribution from both AGN and stellar emission to the observed rest-frame
ultra-violet to far-infrared photometry. We find that both the CSFH and CAGNH
evolve similarly, rising in the early Universe up to a peak at look-back time
~Gyr (), before declining toward the present day. The
key result of this work is that we find the ratio of CAGNH to CSFH has been
flat () for ~Gyr
up to the present day, indicating that star formation and AGN activity have
been coeval over this time period. We find that the stellar masses of the
galaxies that contribute most to the CSFH and CAGNH are similar, implying a
common cause, which is likely gas inflow. The depletion of the gas supply
suppresses cosmic star formation and AGN activity equivalently to ensure that
they have experienced similar declines over the last 10 Gyr. These results are
an important milestone for reconciling the role of star formation and AGN
activity in the life cycle of galaxies.Comment: 16 pages, 10 figures. Figures 9 and 10 are the main results. Accepted
for publication in Monthly Notices of the Royal Astronomical Societ
Engaging Undergraduates in Science Research: Not Just About Faculty Willingness.
Despite the many benefits of involving undergraduates in research and the growing number of undergraduate research programs, few scholars have investigated the factors that affect faculty members' decisions to involve undergraduates in their research projects. We investigated the individual factors and institutional contexts that predict faculty members' likelihood of engaging undergraduates in their research project(s). Using data from the Higher Education Research Institute's 2007-2008 Faculty Survey, we employ hierarchical generalized linear modeling to analyze data from 4,832 science, technology, engineering, and mathematics (STEM) faculty across 194 institutions to examine how organizational citizenship behavior theory and social exchange theory relate to mentoring students in research. Key findings show that faculty who work in the life sciences and those who receive government funding for their research are more likely to involve undergraduates in their research project(s). In addition, faculty at liberal arts or historically Black colleges are significantly more likely to involve undergraduate students in research. Implications for advancing undergraduate research opportunities are discussed
Mechanisms Suppressing Superheavy Element Yields in Cold Fusion Reactions
Superheavy elements are formed in fusion reactions which are hindered by fast nonequilibrium processes. To quantify these, mass-angle distributions and cross sections have been measured, at beam energies from below-barrier to 25% above, for the reactions of 48Ca,50Ti, and 54Cr with 208 Pb. Moving from 48Ca to 54Cr leads to a drastic fall in the symmetric fission yield, which is reflected in the measured mass-angle distribution by the presence of competing fast nonequilibrium deep inelastic and quasifission processes. These are responsible for reduction of the compound nucleus formation probablity PCN (as measured by the symmetric-peaked fission cross section), by a factor of 2.5 for 50Ti and 15 for 54Cr in comparison to 48 Ca. The energy dependence of PCN indicates that cold fusion reactions (involving 208Pb) are not driven by a diffusion process.The authors acknowledge the Australian Research Council
for support through Discovery Grants No. DP140101337, No. DP160101254, No. DP170102318, No. FL110100098,
and No. DE140100784. Financial support from the NCRIS
HIA capability for operation of the Heavy Ion Accelerator
Facility is acknowledged. The authors acknowledge the
support of the German Academic Exchange Service
(DAAD) via funds of the German Federal Ministry of
Education and Research (BMBF)
Concert recording 2017-04-23b
[Track 1]. Slowing down. I. Rotations in an emergency [Track 2]. II. Under the city [Track 3]. III. Forfeit [Track 4]. IV. Something comfortable to fall into / Jeremiah Flannery
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