122 research outputs found
Maximum Entropy Estimation of the Galactic Bulge Morphology via the VVV Red Clump
The abundance and narrow magnitude dispersion of Red Clump (RC) stars make
them a popular candidate for mapping the morphology of the bulge region of the
Milky Way. Using an estimate of the RC's intrinsic luminosity function, we
extracted the three-dimensional density distribution of the RC from deep
photometric catalogues of the VISTA Variables in the Via Lactea (VVV) survey.
We used maximum entropy based deconvolution to extract the spatial distribution
of the bulge from Ks-band star counts. We obtained our extrapolated
non-parametric model of the bulge over the inner 40 by 40 degrees squared
region of the Galactic centre. Our reconstruction also naturally matches onto a
parametric fit to the bulge outside the VVV region and inpaints overcrowded and
high extinction regions. We found a range of bulge properties consistent with
other recent investigations based on the VVV data. In particular, we estimated
the bulge mass to be in the range 13 to 17 billion solar masses, the
X-component to be between 18% and 25% of the bulge mass, and the bulge angle
with respect to the Sun-Galactic centre line to be between 18 and 32 degrees.
Studies of the Fermi Large Area Telescope (LAT) gamma-ray Galactic centre
excess suggests that the excess may be traced by Galactic bulge distributed
sources. We applied our deconvolved density in a template fitting analysis of
this Fermi-LAT GeV excess and found an improvement in the fit compared to
previous parametric based templates.Comment: 25 pages, 27 figures, minor typo correcte
Non-Parametric Density Reconstruction of the Galactic Bulge Area using Red Clump Stars in the VVV Survey
Studies of the red clump giant population in the inner Milky Way suggest the
Galactic bulge/bar has a boxy/peanut/X-shaped structure as predicted by its
formation via a disc buckling instability. We used a non-parametric method of
estimating the Galactic bulge morphology that is based on maximum entropy
regularisation. This enabled us to extract the three-dimensional distribution
of the red giant stars in the bulge from deep photometric catalogues of the
VISTA Variables in the Via Lactea (VVV) survey. Our high-resolution
reconstruction confirms the well-known boxy/peanut/X-shaped structure of the
bulge. We also find spiral arm structures that extend to around three kpc in
front of and behind the bulge and are on different sides of the bulge major
axis. We show that the detection of these structures is robust to the
uncertainties in the luminosity function.Comment: 12 pages, 8 figures, V4: MNRAS accepted versio
Methods of Evaluating 3D Perception Systems for Unstructured Autonomous Logistics
This study introduces methods of evaluating 3D perception systems, such as Time of Flight (ToF) systems, for automated logistics applications in unstructured environments. Here perception is defined as a system’s understanding of its environment and the Objects Of Interest (OOI) within that environment, through hardware consisting of cameras or depth sensors. Current computer guided machinery that rely on perception systems, such as an Autonomous Guided Vehicle (AGV), require structured environments that are specifically designed for such a machine. Unstructured environments include warehouses or manufacturing facilities that have not been tailor designed or structured specifically for the purpose of using a computer guided machine. In this study, two methods are proposed to assess 3D systems proposed for autonomous logistics in unstructured environments. The results of this study indicate that the methods presented here are suitable for future and comparative 3D perception and evaluation in this space
Analysing chem/bio-Markers in saliva using a portable optical detection platform
Bipolar Disorder is commonly regulated using a varying dosage of Lithium carbonate and monitored by blood analysis. The proximity of the upper dosage level in blood (1.2mmol), to that of toxicity (>1.5mmol), presents a risk for patient wellbeing from overdose. The infrequency of blood testing creates a potential for overdose to occur between sampling and remain undetected. Additionally, the invasive and often painful nature of frequent blood draws has resulted in the search for alternative non-invasive techniques. One such medium is saliva and we describe the use of simple, well established, optical techniques integrated into a portable wireless device to analyze Chemical and Bio-markers present in this medium. This novel device allows for frequent, real-time monitoring of drug levels (Lithium) and patient psychological state (alpha-amylase) as well as supplementing patient assessments with their Physician and giving the patient a more personalised monitoring of their health during Lithium treatment
Graph Neural Network-based Tracking as a Service
Recent studies have shown promising results for track finding in dense
environments using Graph Neural Network (GNN)-based algorithms. However,
GNN-based track finding is computationally slow on CPUs, necessitating the use
of coprocessors to accelerate the inference time. Additionally, the large input
graph size demands a large device memory for efficient computation, a
requirement not met by all computing facilities used for particle physics
experiments, particularly those lacking advanced GPUs. Furthermore, deploying
the GNN-based track-finding algorithm in a production environment requires the
installation of all dependent software packages, exclusively utilized by this
algorithm. These computing challenges must be addressed for the successful
implementation of GNN-based track-finding algorithm into production settings.
In response, we introduce a ``GNN-based tracking as a service'' approach,
incorporating a custom backend within the NVIDIA Triton inference server to
facilitate GNN-based tracking. This paper presents the performance of this
approach using the Perlmutter supercomputer at NERSC.Comment: 7 pages, 4 figures, Proceeding of Connected the Dots Workshop (CTD
2023
Herbert Hoover Elementary / Charleston Complete Corridor Plan
Completed as a part of CRP 425 bicycle and pedestrian planning, led by Dr. William Riggs, this planning project assessed the Herbert Hoover Elementary site and Charleston corridor in the City of Palo Alto with an aim to bring a complete streets strategy to the area. The plans recommend improved accessibility for bicycles and pedestrians along Charleston Road including modal separation between bicyclists and pedestians, improved vehicular flows to mitigate vehicular traffic congestion during peak hours and increased innovation in safety features to prevent pedestrian-vehicle conflicts
Confusion and Conflict in Assessing the Physical Activity Status of Middle-Aged Men
BACKGROUND: Physical activity (including exercise) is prescribed for health and there are various recommendations that can be used to gauge physical activity status. The objective of the current study was to determine whether twelve commonly-used physical activity recommendations similarly classified middle-aged men as sufficiently active for general health. METHODS AND FINDINGS: We examined the commonality in the classification of physical activity status between twelve variations of physical activity recommendations for general health in ninety men aged 45-64 years. Physical activity was assessed using synchronised accelerometry and heart rate. Using different guidelines but the same raw data, the proportion of men defined as active ranged from to 11% to 98% for individual recommendations (median 73%, IQR 30% to 87%). There was very poor absolute agreement between the recommendations, with an intraclass correlation coefficient (A,1) of 0.24 (95% CI, 0.15 to 0.34). Only 8% of men met all 12 recommendations and would therefore be unanimously classified as active and only one man failed to meet every recommendation and would therefore be unanimously classified as not sufficiently active. The wide variability in physical activity classification was explained by ostensibly subtle differences between the 12 recommendations for thresholds related to activity volume (time or energy), distribution (e.g., number of days of the week), moderate intensity cut-point (e.g., 3 vs. 4 metabolic equivalents or METs), and duration (including bout length). CONCLUSIONS: Physical activity status varies enormously depending on the physical activity recommendation that is applied and even ostensibly small differences have a major impact. Approximately nine out of every ten men in the present study could be variably described as either active or not sufficiently active. Either the effective dose or prescription that underlies each physical activity recommendation is different or each recommendation is seeking the same prescriptive outcome but with variable success
Search for Pair-Produced Resonances Decaying to Quark Pairs in Proton-Proton Collisions at √s = 13 TeV
A general search for the pair production of resonances, each decaying to two quarks, is reported. The search is conducted separately for heavier resonances (masses above 400 GeV), where each of the four final-state quarks generates a hadronic jet resulting in a four-jet signature, and for lighter resonances (masses between 80 and 400 GeV), where the pair of quarks from each resonance is collimated and reconstructed as a single jet resulting in a two-jet signature. In addition, a b-tagged selection is applied to target resonances with a bottom quark in the final state. The analysis uses data collected with the CMS detector at the CERN LHC, corresponding to an integrated luminosity of 35.9 fb⁻¹, from proton-proton collisions at a center-of-mass energy of 13 TeV. The mass spectra are analyzed for the presence of new resonances, and are found to be consistent with standard model expectations. The results are interpreted in the framework of R-parity-violating supersymmetry assuming the pair production of scalar top quarks decaying via the hadronic coupling λ′′312 or λ′′323 and upper limits on the cross section as a function of the top squark mass are set. These results probe a wider range of masses than previously explored at the LHC, and extend the top squark mass limits in the ˜t→qq′ scenario
Search for a new scalar resonance decaying to a pair of Z bosons in proton-proton collisions at √s=13 TeV
A search for a new scalar resonance decaying to a pair of Z bosons is performed in the mass range from 130 GeV to 3 TeV, and for various width scenarios. The analysis is based on proton-proton collisions recorded by the CMS experiment at the LHC in 2016, corresponding to an integrated luminosity of 35.9 fb⁻¹ at a center-of-mass energy of 13 TeV. The Z boson pair decays are reconstructed using the 4ℓ, 2ℓ2q, and 2ℓ2ν final states, where ℓ = e or μ. Both gluon fusion and electroweak production of the scalar resonance are considered, with a free parameter describing their relative cross sections. A dedicated categorization of events, based on the kinematic properties of associated jets, and matrix element techniques are employed for an optimal signal and background separation. A description of the interference between signal and background amplitudes for a resonance of an arbitrary width is included. No significant excess of events with respect to the standard model expectation is observed and limits are set on the product of the cross section for a new scalar boson and the branching fraction for its decay to ZZ for a large range of masses and widths. Keywords: Hadron-Hadron scattering (experiments); Higgs physic
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