Precision kinematics and related parameters of the α Persei open cluster

A kinematical study of the nearby open cluster α Persei is presented based on the astrometric proper motions and positions in the Tycho-2 catalog and Second USNO CCD Astrographic Catalog (UCAC2). Using the astrometric data and photometry from the Tycho-2 and ground-based catalogs, 139 probable members of the cluster are selected, 18 of them new. By the classical convergent point method, systematic motions of stars inside the cluster and velocity dispersions are estimated. As directly observed, the upper limit on the internal velocity dispersion per coordinate is 1.1 km s^(-1). The actual velocity dispersion is much smaller than that value, since all of it appears to come from the expected errors of the astrometric proper motions. The relative position of the convergent point with respect to the cluster stars yields the "astrometric" radial velocity, which turns out larger by a few km s^(-1) than the mean observed spectroscopic radial velocity. This implies an overall contraction of the cluster. Kinematic parallaxes are computed for each member, and an improved H-R diagram is constructed. An age of 52 Myr is determined by isochrone fitting. The star α Per itself fits an isochrone of this age computed with overshooting from the boundary of the convective zone. The theoretical mass of the star α Per is 6.65 M_⊙. With respect to the common center of mass, half of the higher mass members (earlier than G) are located within a radius of 10.3 pc. The cluster appears to be roughly twice as large, or as sparse, as the Pleiades, retaining nonetheless a similar dynamical coherence. The low rate of binaries is another feature of this cluster, where we find only about 20% of members to be known or suspected spectroscopic, astrometric, or visual binaries or multiple systems. X-ray emitters in the cluster appear to have the same dispersion of internal velocities as the rest of the membership. The cluster is surrounded by an extended, sparse halo of comoving dwarfs, which are found by combining the proper-motion data from UCAC2 with Two Micron All-Sky Survey infrared photometry. Since many of these external stars are outside the tidal radius, the cluster being in an active stage of disintegration or evaporation could be considered. This hypothesis is not supported by the weak compression and the nonmeasurable velocity dispersion found in the kinematic analysis. A search for stars ejected from the α Persei cluster is carried out by tracking a large number of nearby stars 70 Myr back in time and matching their positions with the past location of the cluster. Only one plausible ejection is found prior to 10 Myr ago. The nearby star GJ 82, an active M dwarf with a strong Hα emission, is likely a former member ejected 47 Myr ago at 5 km s^(-1)

European Venture Philanthropy and Social Investment 2011/2012: The EVPA Survey

These are the key results of the second report on the European Venture Philanthropy Industry published by the European Venture Philanthropy Association. The purpose of the report is to provide key statistics and raise awareness about a sector that is evolving rapidly so as to attract further resources to the sector. Data has been collected from 61 leading venture philanthropy and social investment organisations (VPOs) across 18 European countries

Exploring Text Virality in Social Networks

This paper aims to shed some light on the concept of virality - especially in social networks - and to provide new insights on its structure. We argue that: (a) virality is a phenomenon strictly connected to the nature of the content being spread, rather than to the influencers who spread it, (b) virality is a phenomenon with many facets, i.e. under this generic term several different effects of persuasive communication are comprised and they only partially overlap. To give ground to our claims, we provide initial experiments in a machine learning framework to show how various aspects of virality can be independently predicted according to content features

Twittering away - Is Twitter an appropriate adjunctive tool to enhance learning and engagement in higher education?

Twitter is a social media platform that has been used in teaching and learning. The aim was to explore students’ views of using Twitter as an adjunctive learning tool to provide access to contemporary information, to enhance learning and to generate wider discussion via Twitter backchannel communication. A 17-item Qualtrics questionnaire consisting of open and closed questions was devised specifically for the study. Qualitative data was analysed using descriptive statistics. Qualitative data via thematic analysis. Participants were a convenience sample of 44 Level 4 Social Welfare Law students who were invited to engage online with the academic and professional community via Twitter. Eleven (25%) students responded to the questionnaire. Four key themes emerged from the qualitative data: Enhancing knowledge; Building academic and professional networks; Time for twitter and the Need for Twitter training. Despite the limitations, the results suggest that if supported by institutional digital scaffolding and training, twitter may be a useful adjunct to traditional physical learning spaces. Further research is r however required to explore the future pedagogic potential of Twitter.N/

Lonely heart columns: A novel and entertaining way of teaching students abstract writing skills

Abstract writing is a key skill for science graduates; they are a common feature in many of the standard forms of scientific dissemination such as scientific research articles. In this paper we present a novel and entertaining approach for teaching abstract writing using adverts from lonely heart columns (LHC). Student constructed full profiles of the authors of LHC and constructed LHC profiles of celebrities to illustrate the key sills in abstract construction. There was no significant difference between the grades achieved by student taught using LHC and a more traditional approach, suggesting there were no negative impacts from this delivery method. Student in LHC tutorial overwhelmingly enjoy the tutorial, 95% responded the question ‘how would you rate the enjoyment of this tutorial’ as ‘much’ or ‘very much’. In addition to abstract writing two thirds of students in LHC tutorial believed they improved their ability to speak in front of others and their creative thinking skills. The LHC tutorial is a novel approach to teaching and learning that is both enjoyable and effective

Case Study - IPv6 based building automation solution integration into an IPv4 Network Service Provider infrastructure

The case study presents a case study describing an Internet Protocol (IP) version 6 (v6) introduction to an IPv4 Internet Service Provider (ISP) network infrastructure. The case study driver is an ISP willing to introduce a new “killer” service related to Internet of Things (IoT) style building automation. The provider and cooperation of third party companies specialized in building automation will provide the service. The ISP has to deliver the network access layer and to accommodate the building automation solution traffic throughout its network infrastructure. The third party companies are system integrators and building automation solution vendors. IPv6 is suitable for such solutions due to the following reasons. The operator can’t accommodate large number of IPv4 embedded devices in its current network due to the lack of address space and the fact that many of those will need clear 2 way IP communication channel. The Authors propose a strategy for IPv6 introduction into operator infrastructure based on the current network architecture present service portfolio and several transition mechanisms. The strategy has been applied in laboratory with setup close enough to the current operator’s network. The criterion for a successful experiment is full two-way IPv6 application layer connectivity between the IPv6 server and the IPv6 Internet of Things (IoT) cloud