3,618 research outputs found
Northern European retired residents in nine southern European areas: characteristics, motivations and adjustment
During the last two decades, northern European retirement residence in the southern European sunbelt has grown strongly and its forms have rapidly changed, but standard demographic and social statistical sources provide no information about the flows, the migrants or their increasingly mobile and complex residential patterns. Considerable primary research has however recently been undertaken into the causes, conditions, experiences and consequences of international retirement migration (IRM) by investigators from Germany, Spain, Switzerland and the United Kingdom. Many collaborated when designing their studies and instruments, and all have subsequently worked together in a European Science Foundation Scientific Network.
This paper compares the findings of six systematic social surveys in (to be more precise than the title) eight regions of southern Europe and the Canary Islands: all that have tackled similar research questions with similar methods and instruments. It presents interpretations of several comparative tables compiled from their original data, with a focus on the socio-economic backgrounds, motivations and behaviour of the various migrant groups and their relationship with the host and home countries. The paper presents new findings about the typical and variant forms of IRM, and additional understanding of the heterogeneity of the retirees of different nations and in the several regions
Anonymity Metrics Revisited
In 2001, two information theoretic anonymity metrics were proposed: the "effective anonymity set size" and the "degree of anonymity". In this talk, we propose an abstract model for a general anonymity system which is consistent with the definition of anonymity on which the metrics are based. We revisit entropy-based anonymity metrics, and we apply them to Crowds, a practical
anonymity system. We discuss the differences between the two metrics
and the results obtained in the example
The Evolution of the Bel Canto Technique Through the 20th and 21st Century: Annotated Bibliography
The Bel canto technique is the quintessential technique of opera performance. Throughout history, it has adapted itself and survived through pedagogies, composers, influential artists, and scientific specialists from the field. Although the bel canto technique has a wide range of sources and complete history, this will focus more on the evolution occurring through the 20th and 21st centuries. How the bel canto technique has managed to survive is key to understanding its future
Angiotensin-converting enzyme inhibitors stimulate cerebral arteriogenesis
A potent stimulatory effect of Angiotensin-converting-enzyme inhibitors (ACEI) on cerebralarteriogenesis, involving bradykinin, was recently demonstrated by Hillmeister et. al, in a ratmodel of three-vessel occlusion. The evidences presented by the authors show clearly that thecollateral growth in the posterior cerebral artery occurs, resulting in blood supply and cerebralautoregulation recovery.Fil: Bregonzio Diaz, Claudia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - CĂłrdoba. Instituto de FarmacologĂa Experimental de CĂłrdoba. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Instituto de FarmacologĂa Experimental de CĂłrdoba; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica. Departamento de FarmacologĂa; Argentin
On the Measurement of Privacy as an Attacker's Estimation Error
A wide variety of privacy metrics have been proposed in the literature to
evaluate the level of protection offered by privacy enhancing-technologies.
Most of these metrics are specific to concrete systems and adversarial models,
and are difficult to generalize or translate to other contexts. Furthermore, a
better understanding of the relationships between the different privacy metrics
is needed to enable more grounded and systematic approach to measuring privacy,
as well as to assist systems designers in selecting the most appropriate metric
for a given application.
In this work we propose a theoretical framework for privacy-preserving
systems, endowed with a general definition of privacy in terms of the
estimation error incurred by an attacker who aims to disclose the private
information that the system is designed to conceal. We show that our framework
permits interpreting and comparing a number of well-known metrics under a
common perspective. The arguments behind these interpretations are based on
fundamental results related to the theories of information, probability and
Bayes decision.Comment: This paper has 18 pages and 17 figure
A sample of Seyfert-2 galaxies with ultra-luminous galaxy-wide NLRs -- Quasar light echos?
We report the discovery of Seyfert-2 galaxies in SDSS-DR8 with galaxy-wide,
ultra-luminous narrow-line regions (NLRs) at redshifts z=0.2-0.6. With a space
density of 4.4 per cubic Gpc at z~0.3, these "Green Beans" (GBs) are amongst
the rarest objects in the Universe. We are witnessing an exceptional and/or
short-lived phenomenon in the life cycle of AGN. The main focus of this paper
is on a detailed analysis of the GB prototype galaxy J2240-0927 (z=0.326). Its
NLR extends over 26x44 kpc and is surrounded by an extended narrow-line region
(ENLR). With a total [OIII]5008 luminosity of (5.7+/-0.9)x10e43 erg/s, this is
one of the most luminous NLR known around any type-2 galaxy. Using VLT/XSHOOTER
we show that the NLR is powered by an AGN, and we derive resolved extinction,
density and ionization maps. Gas kinematics is disturbed on a global scale, and
high velocity outflows are absent or faint. This NLR is unlike any other NLR or
extended emission line region (EELR) known. Spectroscopy with Gemini/GMOS
reveals extended, high luminosity [OIII] emission also in other GBs. WISE
24micron luminosities are 5-50 times lower than predicted by the [OIII] fluxes,
suggesting that the NLRs reflect earlier, very active quasar states that have
strongly subsided in less than a galaxies' light crossing time. These light
echos are about 100 times more luminous than any other such light echo known to
date. X-ray data are needed for photo-ionization modeling and to verify the
light echos.Comment: This is an update of our previous submission (1211.7098). Apart from
layout it is identical to the publication in ApJ. Compared to v1 (1211.7098)
type settings and language errors have been corrected. We also added 4 more
redshifts, confirming 3 sources (objects #002, #017, #21) and rejecting one
(#020, low-z HII region
Are compact groups hostile towards faint galaxies?
The goal of this work is to understand whether the extreme environment of
compact groups can affect the distribution and abundance of faint galaxies
around them. We performed an analysis of the faint galaxy population in the
vicinity of compact groups and normal groups. We built a light-cone mock galaxy
catalogue constructed from the Millennium Run Simulation II plus a
semi-analytical model of galaxy formation. We identified a sample of compact
groups in the mock catalogue as well as a control sample of normal galaxy
groups and computed the projected number density profiles of faint galaxies
around the first- and the second-ranked galaxies. We also compared the profiles
obtained from the semi-analytical galaxies in compact groups with those
obtained from observational data. In addition, we investigated whether the
ranking or the luminosity of a galaxy is the most important parameter in the
determination of the centre around which the clustering of faint galaxies
occurs. There is no particular influence of the extreme compact group
environment on the number of faint galaxies in such groups compared to control
groups. When selecting normal groups with separations between the 1st and 2nd
ranked galaxies similar to what is observed in compact groups, the faint galaxy
projected number density profiles in compact groups and normal groups are
similar in shape and height. We observed a similar behaviour of the population
of faint galaxies in observations and simulations in the regions closer to the
1st and 2nd ranked galaxies. Finally, we find that the projected density of
faint galaxies is higher around luminous galaxies,regardless of the ranking in
the compact group. The semi-analytical approach shows that compact groups and
their surroundings do not represent a hostile enough environment to make faint
galaxies to behave differently than in normal groups.Comment: 12 pages, 10 figures. Accepted for publication in Astronomy &
Astrophysic
VerLoc: Verifiable Localization in Decentralized Systems
This paper tackles the challenge of reliably determining the geo-location of
nodes in decentralized networks, considering adversarial settings and without
depending on any trusted landmarks. In particular, we consider active
adversaries that control a subset of nodes, announce false locations and
strategically manipulate measurements. To address this problem we propose,
implement and evaluate VerLoc, a system that allows verifying the claimed
geo-locations of network nodes in a fully decentralized manner. VerLoc securely
schedules roundtrip time (RTT) measurements between randomly chosen pairs of
nodes. Trilateration is then applied to the set of measurements to verify
claimed geo-locations. We evaluate VerLoc both with simulations and in the wild
using a prototype implementation integrated in the Nym network (currently run
by thousands of nodes). We find that VerLoc can localize nodes in the wild with
a median error of 60km, and that in attack simulations it is capable of
detecting and filtering out adversarial timing manipulations for network setups
with up to 20% malicious nodes
- …