Common Origin of (-)^L, (-)^{3B}, and Strong CP Conservation

The multiplicative conservation of both lepton and baryon numbers, i.e. (-)^L and (-)^{3B}, is connected to an axionic solution of the strong CP problem in a supersymmetric, unifiable model of quark and lepton interactions. New particles are predicted at the TeV scale, with verifiable consequences at the Large Hadron Collider.Comment: 9 pages, no figur

A catalog of Kazarian galaxies

The entire Kazarian galaxies (KG) catalog is presented which combines extensive new measurements of their optical parameters with a literature and database search. The measurements were made using images extracted from the STScI Digitized Sky Survey (DSS) of Jpg(blue), Fpg(red) and Ipg(NIR) band photographic sky survey plates obtained by the Palomar and UK Schmidt telescopes. We provide accurate coordinates, morphological type, spectral and activity classes, blue apparent diameters, axial ratios, position angles, red, blue and NIR apparent magnitudes, as well as counts of neighboring objects in a circle of radius 50 kpc from centers of KG. Special attention was paid to the individual descriptions of the galaxies in the original Kazarian lists, which clarified many cases of misidentifications of the objects, particularly among interacting systems. The total number of individual Kazarian objects in the database is now 706. We also include the redshifts which are now available for 404 galaxies and the 2MASS infrared magnitudes for 598 KG. The database also includes extensive notes, which summarize information about the membership of KG in different systems of galaxies, and about revised activity classes and redshifts. An atlas of several interesting subclasses of KG is also presented.Comment: 15 pages, 5 figures, 1 table, Accepted in Astrophysics, Vol. 53, No. 1, 2010 (English translation of Astrofizika

From Large to Small Scales: Global Models of the ISM

We review large scale modelling of the ISM with emphasis on the importance to include the disk-halo-disk duty cycle and to use a dynamical refinement of the grid (in regions where steep variations of density and pressure occur) for a realistic modelling of the ISM. We also discuss the necessity of convergence of the simulation results by comparing 0.625, 1.25 and 2.5 pc resolution simulations and show that a minimum grid resolution of 1.25 pc is required for quantitatively reliable results, as there is a rapid convergence for Delta x \leq 1.1 pc.Comment: 10 pages, 8 figures that include 2 simulation images (in jpeg format) and 6 plots (4 in ps and 2 in jpeg formats), to appear in the proceedings of ``From Observations to Self-Consistent Modelling of the ISM in Galaxies'', Kluwe

Measuring an entropy in heavy ion collisions

We propose to use the coincidence method of Ma to measure an entropy of the system created in heavy ion collisions. Moreover we estimate, in a simple model, the values of parameters for which the thermodynamical behaviour sets in.Comment: LATTICE98(hightemp), 3 pages, LaTeX with two eps figure

Analysing the EAP-TLS handshake and the 4-way handshake of the 802.11i standard

The IEEE 802.11i standard has been designed to enhance security in wireless networks. The EAP-TLS handshake aims to provide mutual authentication between supplicant and authentication server, and then derive the Pairwise Master Key (PMK). In the 4 -way handshake the supplicant and the authenticator use PMK to derive a fresh pairwise transient key (PTK). The PMK is not used directly for security while assuming the supplicant and authenticator have the same PMK before running 4- way handshake. In this paper, the EAP-TLS handshake and the 4-way handshake phases have been analysed with a proposed framework using Isabelle tool. In the analysis, we have found a new Denial-of-Service (DoS) attack in the 4-way handshake. The attack prevents the authenticator from receiving message 4 after the supplicant sends it out. This attack forces the authenticator to re-send the message 3 until time out and subsequently to de-authenticate supplicant. This paper has proposed improvements to the 4-way handshake to avoid the Denial-of-Service attack

Gathering realistic authentication performance data through field trials

Most evaluations of novel authentication mechanisms have been conducted under laboratory conditions. We argue that the results of short-term usage under laboratory conditions do not predict user performance “in the wild”, because there is insufficient time between enrolment and testing, the number of authentications is low, and authentication is presented as a primary task, rather then the secondary task as it is “in the wild”. User generated reports of performance on the other hand provide subjective data, so reports on frequency of use, time intervals, and success or failure of authentication are subject to the vagaries of users ’ memories. Studies on authentication that provide objective performance data under real-world conditions are rare. In this paper, we present our experiences with a study method that tries to control frequency and timing of authentication, and collects reliable performance data, while maintaining ecological validity of the authentication context at the same time. We describe the development of an authentication server called APET, which allows us to prompt users enrolled in trial cohorts to authenticate at controlled intervals, and report our initial experiences with trials. We conclude by discussing remaining challenges in obtaining reliable performance data through a field trial method such as this one

Human-centred identity - from rhetoric to reality

This paper presents a proposal for human-centred identity management. Even though the term ‘human-centred identity’ has been widely used in the past few years, the solutions either descritbe a technical system for managing identity, or describe an identity management solution that meets a particular administrative need. Our proposal, however, presents a set of propertis that have to be considered, and the choices have to be made for each property must satisfy the needs of both the individual and the organization that owns the identity management system. The properties were identified as a result of reviewing a range of national identity systems, and the problems that arise from them

Users are not the enemy

Many system security departments treat users as a security risk to be controlled. The general consensus is that most users are careless and unmotivated when it comes to system security. In a recent study, we found that users may indeed compromise computer security mechanisms, such as password authentication, both knowing and unknowingly. A closer analysis, however, revealed that such behavior is often caused by the way in which security mechanisms are implemented, and users ’ lack of knowledge. We argue that to change this state of affairs, security departments need to communicate more with users, and adopt a user-centered design approach

Participants’ reflections on being interviewed about risk and sexual behaviour: implications for collection of qualitative data on sensitive topics

In this article, we explore how those taking part in an interview about sex and risk reflected on their participation and what, if any, impact it had on them. All 22 individuals who were interviewed in an initial study were invited to document their thoughts and feelings about the research process in a short follow-up exercise. The data relating to the 11 people who shared their reflections on the interview were subjected to a thematic analysis. The themes that emerged describe the value participants placed on honest and open interaction within neutral and non-judgmental environments. They also illustrate how being interviewed about prior behaviour can facilitate a sense-making process and might provide some degree of cathartic benefit. The findings help improve our understanding of how individuals reflect on their interview participation, which can in turn help to inform the development of ethically sensitive qualitative data collection

On pairwise distances and median score of three genomes under DCJ

In comparative genomics, the rearrangement distance between two genomes (equal the minimal number of genome rearrangements required to transform them into a single genome) is often used for measuring their evolutionary remoteness. Generalization of this measure to three genomes is known as the median score (while a resulting genome is called median genome). In contrast to the rearrangement distance between two genomes which can be computed in linear time, computing the median score for three genomes is NP-hard. This inspires a quest for simpler and faster approximations for the median score, the most natural of which appears to be the halved sum of pairwise distances which in fact represents a lower bound for the median score. In this work, we study relationship and interplay of pairwise distances between three genomes and their median score under the model of Double-Cut-and-Join (DCJ) rearrangements. Most remarkably we show that while a rearrangement may change the sum of pairwise distances by at most 2 (and thus change the lower bound by at most 1), even the most "powerful" rearrangements in this respect that increase the lower bound by 1 (by moving one genome farther away from each of the other two genomes), which we call strong, do not necessarily affect the median score. This observation implies that the two measures are not as well-correlated as one's intuition may suggest. We further prove that the median score attains the lower bound exactly on the triples of genomes that can be obtained from a single genome with strong rearrangements. While the sum of pairwise distances with the factor 2/3 represents an upper bound for the median score, its tightness remains unclear. Nonetheless, we show that the difference of the median score and its lower bound is not bounded by a constant.Comment: Proceedings of the 10-th Annual RECOMB Satellite Workshop on Comparative Genomics (RECOMB-CG), 2012. (to appear