624 research outputs found
A new low mass for the Hercules dSph: the end of a common mass scale for the dwarfs?
We present a new mass estimate for the Hercules dwarf spheroidal galaxy
(dSph), based on the revised velocity dispersion obtained by Aden et al. (2009,
arXiv:0908.3489).
The removal of a significant foreground contamination using newly acquired
Stromgren photometry has resulted in a reduced velocity dispersion. Using this
new velocity dispersion of 3.72 +/- 0.91 km/s, we find a mass of
M_300=1.9^{+1.1}_{-0.8} 10^6 M_sun within the central 300 pc, which is also the
half-light radius, and a mass of M_433=3.7_{-1.6}^{+2.2} 10^6 M_sun within the
reach of our data to 433 pc, significantly lower than previous estimates. We
derive an overall mass-to-light ratio of M_433/L=103^{+83}_{-48} M_sun/L_sun.
Our mass estimate calls into question recent claims of a common mass scale for
dSph galaxies.
Additionally, we find tentative evidence for a velocity gradient in our
kinematic data of 16 +/- 3 km/s/kpc, and evidence of an asymmetric extension in
the light distribution at about 0.5 kpc. We explore the possibility that these
features are due to tidal interactions with the Milky Way. We show that there
is a self-consistent model in which Hercules has an assumed tidal radius of r_t
= 485 pc, an orbital pericentre of r_p = 18.5 +/- 5 kpc, and a mass within r_t
of M_{tid,r_t}=5.2 +/- 2.7 10^6 M_sun. Proper motions are required to test this
model. Although we cannot exclude models in which Hercules contains no dark
matter, we argue that Hercules is more likely to be a dark matter dominated
system which is currently experiencing some tidal disturbance of its outer
parts.Comment: 10 pages, 3 figures, Accepted for publication by ApJ
Cholesterol concentration in bovine blood plasma relation with growth rate alkaline phosphatase activity and thyroxine degradation
International audienc
Mask testing of 28 gbaud 16-QAM transmitters using time-resolved error vector magnitude
We propose time-resolved EVM for characterization of 16-QAM transmitters. By designing a mask test, different impairments can be separated and quantified. The impact from quadrature error and timing skew are investigated experimentally
Privacy Mining from IoT-based Smart Homes
Recently, a wide range of smart devices are deployed in a variety of
environments to improve the quality of human life. One of the important
IoT-based applications is smart homes for healthcare, especially for elders.
IoT-based smart homes enable elders' health to be properly monitored and taken
care of. However, elders' privacy might be disclosed from smart homes due to
non-fully protected network communication or other reasons. To demonstrate how
serious this issue is, we introduce in this paper a Privacy Mining Approach
(PMA) to mine privacy from smart homes by conducting a series of deductions and
analyses on sensor datasets generated by smart homes. The experimental results
demonstrate that PMA is able to deduce a global sensor topology for a smart
home and disclose elders' privacy in terms of their house layouts.Comment: This paper, which has 11 pages and 7 figures, has been accepted BWCCA
2018 on 13th August 201
fish freshness decay measurement with a colorimetric artificial olfactory system
Abstract This paper reports about the application of an artificial olfactory system based on optical imaging technology. This arrangement is formed by a distributed layer of chemical indicators illuminated by a computer screen and imaged by a digital camera. The system has been applied to monitor the freshness decay in fish. The set of indicators is formed by porphyrinoids and acid–base indicators, this combination provides an optimal capture of the process with some of the indicators sensitive to first stage, when the product is still fresh, and others more sensitive to the last part of the freshness deca
Adsorption of Fibrinogen on Thin Oriented Poly(Tetrafluoroethylene) (PTFE) Fibres Studied by Scanning Force Microscopy
We have investigated fibrinogen adsorption on ordered poly(tetrafluoroethylene), PTFE, fibres deposited on hydrophilic and hydrophobic silicon substrates. Fibrinogen molecules appear to adsorb with their long axis perpendicular to the fibre direction for PTFE fibres having widths of less than 100 nm. On these thin fibres, fibrinogen apparently forms close packed bands or clusters, consisting of small integer numbers of molecules arranged parallel to each other. On broader (\u3e 100 nm) PTFE fibres, the fibrinogen forms two dimensional networks. The orientation of the molecules in these networks is random in the central flat part of the fibres but perpendicular to the fibre direction at the fibre edges. As a tentative explanation, we propose that the observed orientation may be linked to the radius of curvature of the fibre surface
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