2,227 research outputs found
Improving Air Interface User Privacy in Mobile Telephony
Although the security properties of 3G and 4G mobile networks have
significantly improved by comparison with 2G (GSM), significant shortcomings
remain with respect to user privacy. A number of possible modifications to 2G,
3G and 4G protocols have been proposed designed to provide greater user
privacy; however, they all require significant modifications to existing
deployed infrastructures, which are almost certainly impractical to achieve in
practice. In this article we propose an approach which does not require any
changes to the existing deployed network infrastructures or mobile devices, but
offers improved user identity protection over the air interface. The proposed
scheme makes use of multiple IMSIs for an individual USIM to offer a degree of
pseudonymity for a user. The only changes required are to the operation of the
authentication centre in the home network and to the USIM, and the scheme could
be deployed immediately since it is completely transparent to the existing
mobile telephony infrastructure. We present two different approaches to the use
and management of multiple IMSIs
Comparison of remove-compute-restore and least squares modification of Stokes' formula techniques to quasi-geoid determination over the Auvergne test area
Nonlinear Interactions Between Gravitational Radiation and Modified Alfven Modes in Astrophysical Dusty Plasmas
We present an investigation of nonlinear interactions between Gravitational
Radiation and modified Alfv\'{e}n modes in astrophysical dusty plasmas.
Assuming that stationary charged dust grains form neutralizing background in an
electron-ion-dust plasma, we obtain the three wave coupling coefficients, and
calculate the growth rates for parametrically coupled gravitational radiation
and modified Alfv\'{e}n-Rao modes. The threshold value of the gravitational
wave amplitude associated with convective stabilization is particularly small
if the gravitational frequency is close to twice the modified Alfv\'en
wave-frequency. The implication of our results to astrophysical dusty plasmas
is discussed.Comment: A few typos corrected. Published in Phys. Rev.
The first r-process enhanced star confirmed to be a member of the Galactic bulge
Aims. Stars with strong enhancements of r-process elements are rare and tend
to be metal-poor, with generally [Fe/H] <-2 dex and found in the halo. In this
work we aim to investigate a candidate r-process enriched bulge star with a
relatively high metallicity of -0.65 dex, and compare it with a previously
published r-rich candidate star in the bulge. Methods. We reconsider the
abundance analysis of a high-resolution optical spectrum of the red-giant star
2MASS J18082459-2548444 and determine its europium (Eu) and molybdenum (Mo)
abundance, using stellar parameters from five different previous studies.
Applying 2MASS photometry, Gaia astrometry and kinematics, we estimate
distance, orbits, and population membership of 2MASS J18082459-2548444 and a
previously reported r-enriched star 2MASS J18174532-3353235. Results. We find
that 2MASS J18082459-2548444 is a relatively metal rich enriched r-process star
that is enhanced in Eu and Mo but not substantially enhanced in s-process
elements. It has a high probability of membership in the Galactic bulge based
on its distance and orbit. We find that both stars show r-process enhancement
with elevated [Eu/Fe]-values, even though 2MASS J18174532-3353235 is 1 dex
lower in metallicity. Additionally, we find that 2MASS J18174532-3353235
plausibly has a halo or thick disc origin. Conclusions. We conclude that 2MASS
J18082459-2548444 represents the first example of a confirmed r-process
enhanced star confined to the inner bulge, possibly a relic from a period of
enrichment associated with the formation of the bar.Comment: 9 pages, 8 figures, 3 tables, accepted for publication in A&
Why does visual working memory ability improve with age : more objects, more feature detail, or both? A registered report
We investigated how visual working memory (WM) develops with age across the early elementary school period (6–7 years), early adolescence (11–13 years), and early adulthood (18–25 years). The work focuses on changes in two parameters: the number of objects retained at least in part, and the amount of feature-detail remembered for such objects. Some evidence suggests that, while infants can remember up to three objects, much like adults, young children only remember around two objects. This curious, nonmonotonic trajectory might be explained by differences in the level of feature-detail required for successful performance in infant versus child/adult memory paradigms. Here, we examined if changes in one of two parameters (the number of objects, and the amount of detail retained for each object) or both of them together can explain the development of visual WM ability as children grow older. To test it, we varied the amount of feature-detail participants need to retain. In the baseline condition, participants saw an array of objects and simply were to indicate whether an object was present in a probed location or not. This phase begun with a titration procedure to adjust each individual's array size to yield about 80% correct. In other conditions, we tested memory of not only location but also additional features of the objects (color, and sometimes also orientation). Our results suggest that capacity growth across ages is expressed by both improved location-memory (whether there was an object in a location) and feature completeness of object representations
The Mantis Network III: Expanding the limits of chemical searches within ultra hot-Jupiters. New detections of Ca I, V I, Ti I, Cr I, Ni I, Sr II, Ba II, and Tb II in KELT-9 b
Cross-correlation spectroscopy is an invaluable tool in the study of
exoplanets. However, aliasing between spectral lines makes it vulnerable to
systematic biases. This work strives to constrain the aliases of the
cross-correlation function to provide increased confidence in the detections of
elements in the atmospheres of ultra-hot Jupiters (UHJs) observed with
high-resolution spectrographs. We use a combination of archival transit
observations of the UHJ KELT-9 b obtained with the HARPS-N and CARMENES
spectrographs and show that it is possible to leverage each instrument's
strengths to produce robust detections at substantially reduced
signal-to-noise. Aliases that become present at low signal-to-noise regimes are
constrained through a linear regression model. We confirm previous detections
of H I, Na I, Mg I, Ca II, Sc II, Ti II, Cr II, Fe I, and Fe II, and detect
eight new species Ca I, Cr I, Ni I, Sr II, Tb II at the 5 level and Ti
I, V I, Ba II above the 3 level. Ionised terbium (Tb II) has never
before been seen in an exoplanet atmosphere. We further conclude that a
5 threshold may not provide a reliable measure of confidence when used
to claim detections, unless the systematics in the cross-correlation function
caused by aliases are taken into account.Comment: Accepted for publication on the 1st of April 202
Gene expression of calpains and their specific endogenous inhibitor, calpastatin, in skeletal muscle of fed and fasted rabbits
Subdermal Ultrasound Contrast Agent Injection for Sentinel Lymph Node Identification: An Analysis of Safety and Contrast Agent Dose in Healthy Volunteers.
Objectives—Mapping of the lymphatic chain for identification of the sentinel lymph node (SLN) is an important aspect of predicting outcomes for breast cancer patients, and it is usually performed as an intraoperative procedure using blue dye and/or radiopharmaceuticals agents. Recently the use of contrast-enhanced ultrasound (CEUS) has been proposed as an alternative imaging technique for this mapping. The objective of this study was to evaluate the use of subdermal administration of the ultrasound contrast agent Sonazoid (GE Healthcare) in terms of patient safety and to select the dose to be used for lymphatic applications in humans.
Methods—This study was performed in 12 female volunteers that received bilateral subdermal injections of Sonazoid (1 or 2 ml doses) in the mid-upper outer quadrant of their breasts at two different time-points. CEUS was performed 0, 0.25, 0.5, 1, 2, 4, 6 and 24 hours post-injection to identify SLNs.
Results—SLNs were identified within the first hour post-injection as enhanced structures and there was no significant difference by dose in the number of SLNs identified (p=0.74). Volunteers only experienced minor adverse experiences (AEs) that resolved completely without intervention by study completion.
Conclusion—The subdermal use of Sonazoid in this study showed only minor local and non-significant AEs that were completely resolved without any intervention. Two different doses were compared with no significant differences observed between them. Hence, the lower dose studied (1 ml) was selected for use in future clinical studies
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