Internet users and online privacy: a study assessing whether Internet users' privacy is adequately protected

The paper examines the current state of Internet privacy. We assess the needs of UK Internet users in terms of online privacy protection, and determine the extent to which current privacy practices were satisfying those needs. Our work examines: (a) Internet users' attitudes towards online privacy; (b) 50 Web sites' privacy policies and practices and (c) existing privacy protection for users such as legislation and technological tools. The survey reveals a high level of concerns amongst Internet users related to their privacy in terms of: (i) personally identifying information that they provide to Web sites, (ii) the information that Web sites collect through the use of cookies and IP addresses and (iii) the information derived by tracking users' online activities

Scalar field theory on kappa-Minkowski spacetime and translation and Lorentz invariance

We investigate the properties of kappa-Minkowski spacetime by using representations of the corresponding deformed algebra in terms of undeformed Heisenberg-Weyl algebra. The deformed algebra consists of kappa-Poincare algebra extended with the generators of the deformed Weyl algebra. The part of deformed algebra, generated by rotation, boost and momentum generators, is described by the Hopf algebra structure. The approach used in our considerations is completely Lorentz covariant. We further use an adventages of this approach to consistently construct a star product which has a property that under integration sign it can be replaced by a standard pointwise multiplication, a property that was since known to hold for Moyal, but not also for kappa-Minkowski spacetime. This star product also has generalized trace and cyclic properties and the construction alone is accomplished by considering a classical Dirac operator representation of deformed algebra and by requiring it to be hermitian. We find that the obtained star product is not translationally invariant, leading to a conclusion that the classical Dirac operator representation is the one where translation invariance cannot simultaneously be implemented along with hermiticity. However, due to the integral property satisfied by the star product, noncommutative free scalar field theory does not have a problem with translation symmetry breaking and can be shown to reduce to an ordinary free scalar field theory without nonlocal features and tachionic modes and basicaly of the very same form. The issue of Lorentz invariance of the theory is also discussed.Comment: 22 pages, no figures, revtex4, in new version comments regarding translation invariance and few references are added, accepted for publication in Int. J. Mod. Phys.

The transition to aeration in two-phase mixing in stirred vessels

We consider the mixing of a viscous fluid by the rotation of a pitched blade turbine inside an open, cylindrical tank, with air as the lighter fluid above. To examine the flow and interfacial dynamics, we utilise a highly-parallelised implementation of a hybrid front-tracking/level-set method that employs a domain-decomposition parallelisation strategy. Our numerical technique is designed to capture faithfully complex interfacial deformation, and changes of topology, including interface rupture and dispersed phase coalescence. As shown via transient, three-dimensional direct numerical simulations, the impeller induces the formation of primary vortices that arise in many idealised rotating flows as well as several secondary vortical structures resembling Kelvin-Helmholtz, vortex breakdown, blade tip vortices, and end-wall corner vortices. As the rotation rate increases, a transition to `aeration' is observed when the interface reaches the rotating blades leading to the entrainment of air bubbles into the viscous fluid and the creation of a bubbly, rotating, free surface flow. The mechanisms underlying the aeration transition are probed as are the routes leading to it, which are shown to exhibit a strong dependence on flow history.Comment: 14 pages, 9 figure

Neutron Rich Hypernuclei in Chiral Soliton Model

The binding energies of neutron rich strangeness $S=-1$ hypernuclei are estimated in the chiral soliton approach using the bound state rigid oscillator version of the SU(3) quantization model. Additional binding of strange hypernuclei in comparison with nonstrange neutron rich nuclei takes place at not large values of atomic (baryon) numbers, $A=B\leq\sim 10$. This effect becomes stronger with increasing isospin of nuclides, and for "nuclear variant" of the model with rescaled Skyrme constant $e$. Total binding energies of (Lambda)He-8 and recently discovered (Lambda)H-6 satisfactorily agree with experimental data. Hypernuclei (Lambda)H-7, (Lambda)He-9 are predicted to be bound stronger in comparison with their nonstrange analogues H-7, He-9; hypernuclei (Lambda)Li-10, (Lambda)Li-11, (Lambda)Be-12, (Lambda)Be-13, etc. are bound stronger in the nuclear variant of the model.Comment: 8 pages, 4 tables; amendments made, data on binding energy of (Lambda)He-8 and references added; prepared for the conferences Quarks-2012 and HYP201

The intellectual information system for management of geological and technical arrangements during oil field exploitation

The intellectual information system for management of geological and technical arrangements during oil fields exploitation is developed. Service-oriented architecture of its software is a distinctive feature of the system. The results of the cluster analysis of real field data received by means of this system are shown

The Zwicky Transient Facility Alert Distribution System

The Zwicky Transient Facility (ZTF) survey generates real-time alerts for optical transients, variables, and moving objects discovered in its wide-field survey. We describe the ZTF alert stream distribution and processing (filtering) system. The system uses existing open-source technologies developed in industry: Kafka, a real-time streaming platform, and Avro, a binary serialization format. The technologies used in this system provide a number of advantages for the ZTF use case, including (1) built-in replication, scalability, and stream rewind for the distribution mechanism; (2) structured messages with strictly enforced schemas and dynamic typing for fast parsing; and (3) a Python-based stream processing interface that is similar to batch for a familiar and user-friendly plug-in filter system, all in a modular, primarily containerized system. The production deployment has successfully supported streaming up to 1.2 million alerts or roughly 70 GB of data per night, with each alert available to a consumer within about 10 s of alert candidate production. Data transfer rates of about 80,000 alerts/minute have been observed. In this paper, we discuss this alert distribution and processing system, the design motivations for the technology choices for the framework, performance in production, and how this system may be generally suitable for other alert stream use cases, including the upcoming Large Synoptic Survey Telescope.Comment: Published in PASP Focus Issue on the Zwicky Transient Facility (doi: 10.1088/1538-3873/aae904). 9 Pages, 2 Figure

Is the dark matter interpretation of the EGRET gamma excess compatible with antiproton measurements?

We investigate the internal consistency of the halo dark matter model which has been proposed by de Boer et al. to explain the excess of diffuse galactic gamma rays observed by the EGRET experiment. Any model based on dark matter annihilation into quark jets, such as the supersymmetric model proposed by de Boer et al., inevitably also predicts a primary flux of antiprotons from the same jets. Since propagation of the antiprotons in the unconventional, disk-dominated type of halo model used by de Boer et al. is strongly constrained by the measured ratio of boron to carbon nuclei in cosmic rays, we investigate the viability of the model using the DarkSUSY package to compute the gamma-ray and antiproton fluxes. We are able to show that their model is excluded by a wide margin from the measured flux of antiprotons. We therefore find that a model of the type suggested by Moskalenko et al., where the intensities of protons and electrons in the cosmic rays vary with galactic position, is far more plausible to explain the gamma excess.Comment: 14 pages, 5 figures. Matches published versio

Breaking the self-averaging properties of spatial galaxy fluctuations in the Sloan Digital Sky Survey - Data Release Six

Statistical analyses of finite sample distributions usually assume that fluctuations are self-averaging, i.e. that they are statistically similar in different regions of the given sample volume. By using the scale-length method, we test whether this assumption is satisfied in several samples of the Sloan Digital Sky Survey Data Release Six. We find that the probability density function (PDF) of conditional fluctuations, filtered on large enough spatial scales (i.e., r>30 Mpc/h), shows relevant systematic variations in different sub-volumes of the survey. Instead for scales r<30 Mpc/h the PDF is statistically stable, and its first moment presents scaling behavior with a negative exponent around one. Thus while up to 30 Mpc/h galaxy structures have well-defined power-law correlations, on larger scales it is not possible to consider whole sample average quantities as meaningful and useful statistical descriptors. This situation is due to the fact that galaxy structures correspond to density fluctuations which are too large in amplitude and too extended in space to be self-averaging on such large scales inside the sample volumes: galaxy distribution is inhomogeneous up to the largest scales, i.e. r ~ 100 Mpc/h, probed by the SDSS samples. We show that cosmological corrections, as K-corrections and standard evolutionary corrections, do not qualitatively change the relevant behaviors. Finally we show that the large amplitude galaxy fluctuations observed in the SDSS samples are at odds with the predictions of the standard LCDM model of structure formation.(Abridged version).Comment: 32 pages, 28 figures, accepted for publication in Astronomy and Astrophysics. A higher resolution version is available at http://pil.phys.uniroma1.it/~sylos/fsl_highlights.html . Version v2 has been corrected to match the published on