4,091 research outputs found
Run-time Compilation of Bytecode in Sensor Networks
Recent work on virtual machines for wireless sensor networks has demonstrated the benefits of using a Java programming paradigm for resource constrained sensor networks. Results have shown that a virtual machine approach greatly suffers from interpretation overheads. In this paper, we present run-time compilation of bytecode in wireless sensor networks which leverages from both a compact platform independent bytecode program representation as well as a native execution platform for efficient execution of code. Our results show that run-time compilation provides a substantial decrease in execution overheads when compared with an interpreter
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Longitudinal Intra- and Inter-individual variation in T-cell subsets of HIV-infected and uninfected men participating in the LA Multi-Center AIDS Cohort Study.
To assess the intra-individual and inter-individuals biological variation and the effect of aging on lymphocyte T-cells subsets.We assessed lymphocyte phenotypes (CD3, CD4, and CD8 T-cells) in 89 HIV-1-infected and 88 uninfected white non-Hispanic men every 6 months, to examine the biological variation for those measurements, and the average change in lymphocyte phenotype over 34 years.The markers showed significant intra-individuality in HIV-infected and uninfected individuals with index of individuality of <1.4. No mean changes were seen over the 34 years, with the exception of percentage CD4T-cells in HIV-uninfected individuals.In the pre-HAART era, HIV-infected individuals experienced an increase in mean absolute CD3 T-cell numbers (11.21 cells/μL, P = 0.02) and absolute CD8 T-cell numbers (34.57 cell/μl, P < .001), and in the percentage of CD8 T-cells (1.45%, P < .001) per year and a significant decrease in mean absolute CD4 T-cell numbers (23.68 cells/μl, P < .001) and in the percentage of CD4 T-cells (1.49%, P < .001) per year.In the post-HAART era, no changes in mean levels were observed in absolute CD3 T-cell count (P = .15) or percentage (P = .99). Significant decreases were seen in mean count (8.56 cells/μl, P < .001) and percentage (0.59%, P < .001) of CD8 T-cells, and increases in mean absolute count (10.72 cells/μl, P < .001) and percentage (0.47%, P < .001) of CD4 T-cells.With the exception of CD4 (%), no average changes per year were seen in lymphocyte phenotype of HIV-uninfected men. The results of coefficients of variation of intra and inter-individuals of this study can be useful for HIV-1 infection monitoring and in addition the observation could be a useful guide for intra- and inter-individual coefficient variations, and establishing quality goal studies of different blood biomarkers in healthy and other diseases
Throttling positive semidefinite zero forcing propagation time on graphs
Zero forcing is a process on a graph that colors vertices blue by starting
with some of the vertices blue and applying a color change rule. Throttling
minimizes the sum of the size of the initial blue vertex set and the number of
the time steps needed to color the graph. We study throttling for positive
semidefinite zero forcing. We establish a tight lower bound on the positive
semidefinite throttling number as a function of the order, maximum degree, and
positive semidefinite zero forcing number of the graph, and determine the
positive semidefinite throttling numbers of paths, cycles, and full binary
trees. We characterize the graphs that have extreme positive semidefinite
throttling numbers.Comment: 20 pages, 7 figures, in press, Discrete Appl. Mat
Imaging Scatterometer for Observing In-Situ Changes to Optical Coatings During Air Annealing
Annealing of amorphous optical coatings has been shown to generally reduce
optical absorption, optical scattering, and mechanical loss, with higher
temperature annealing giving better results. The achievable maximum
temperatures are limited to the levels at which coating damage, such as
crystallization, cracking, or bubbling will occur. Coating damage caused by
heating is typically only observed statically, after annealing. An experimental
method to dynamically observe how and over what temperature range such damage
occurs during annealing is desirable as its results could inform manufacturing
and annealing processes to ultimately achieve better coating performance. We
developed a new instrument that features an industrial annealing oven with
holes cut into its sides for viewports to illuminate optical samples and
observe their coating scatter and eventual damage mechanisms in-situ and in
real-time during annealing. We present results that demonstrate in-situ
observation of changes to titania-doped tantala coatings on fused silica
substrates. We obtain a spatial image (mapping) of the evolution of these
changes during annealing, an advantage over x-ray diffraction, electron beam,
or Raman methods. We infer, based on other experiments in the literature, these
changes to be due to crystallization. We further discuss the utility of this
apparatus for observing other forms of coating damage such as cracking and
blisters.Comment: 14 pages, 6 figures, submitted to Applied Optics. arXiv admin note:
text overlap with arXiv:2202.1239
Accurate masses for dispersion-supported galaxies
We derive an accurate mass estimator for dispersion-supported stellar systems
and demonstrate its validity by analyzing resolved line-of-sight velocity data
for globular clusters, dwarf galaxies, and elliptical galaxies. Specifically,
by manipulating the spherical Jeans equation we show that the dynamical mass
enclosed within the 3D deprojected half-light radius r_1/2 can be determined
with only mild assumptions about the spatial variation of the stellar velocity
dispersion anisotropy. We find M_1/2 = 3 \sigma_los^2 r_1/2 / G ~ 4
\sigma_los^2 R_eff / G, where \sigma_los^2 is the luminosity-weighted square of
the line-of-sight velocity dispersion and R_eff is the 2D projected half-light
radius. While deceptively familiar in form, this formula is not the virial
theorem, which cannot be used to determine accurate masses unless the radial
profile of the total mass is known a priori. We utilize this finding to show
that all of the Milky Way dwarf spheroidal galaxies (MW dSphs) are consistent
with having formed within a halo of mass approximately 3 x 10^9 M_sun in Lambda
CDM cosmology. The faintest MW dSphs seem to have formed in dark matter halos
that are at least as massive as those of the brightest MW dSphs, despite the
almost five orders of magnitude spread in luminosity. We expand our analysis to
the full range of observed dispersion-supported stellar systems and examine
their I-band mass-to-light ratios (M/L). The M/L vs. M_1/2 relation for
dispersion-supported galaxies follows a U-shape, with a broad minimum near M/L
~ 3 that spans dwarf elliptical galaxies to normal ellipticals, a steep rise to
M/L ~ 3,200 for ultra-faint dSphs, and a more shallow rise to M/L ~ 800 for
galaxy cluster spheroids.Comment: 20 pages, 13 figures. Accepted to MNRAS on March 27th, 201
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