Predictions of the solar wind interaction with Comet Grigg-Skjellerup

The planned encounter of the Giotto spacecraft with comet Grigg-Skjellerup on 10th July 1992 promises to extend our knowledge of the solar wind interaction with comets substantially. While there have been spacecraft missions to comets before now, this mission is exploratory in the sense that the target comet is much older and there-fore it has a much lower gas production rate than comets Halley (by a factor approximately 200) or Giacobini-Zinner (factor approximately 10). Here we present theoretical predictions for the location of the bow shock and contact surface features, and compare similar predictions with the observed features at the previous encounters. We discuss the applicability of fluid-type theory which these models employ, in the case of strong and weak comets in the solar wind

Responding to Gender-based Violence in Scotland: The Scope of the Gender Equality Duty to Drive Cultural and Practical Change

This piece of research has its roots in well-established policy debates in Scotland. Following the passage of the Criminal Justice (Scotland) Act 2003, which introduced a new statutory aggravation for crimes motivated by religious prejudice, the then Scottish Executive convened a working group to explore and make recommendations on whether there was a case for similar provision for other social groups. The report and recommendations of the Hate Crime Working Group, published in 2004, recognised that the debate to introduce gender aggravation was one of the most contested issues which it had looked at, but it did not believe that at that stage it could recommend introducing such a provision. These debates re-emerged with Patrick Harvie’s member’s bill which was to become the Offences (Aggravation by Prejudice) (Scotland) Act 2009. The Equality and Human Rights Commission, along with many organisations in the women’s sector in Scotland, stated in its evidence on the bill that it did not believe that a statutory gender aggravation would be an effective additional criminal justice response to identifying and tackling crime motivated by gender prejudice. This of course begs the question about what is required to better address these types of crime. This piece of research, undertaken for the EHRC by the Scottish Centre for Crime and Justice Research, aims to be a useful contribution to this debate. It explores some of the arguments for and against a gender aggravation in Scots criminal law before considering the evidence thus far of the impact the Gender Equality Duty (GED) has had on Scotland’s criminal justice system, and makes a number of useful recommendations for the future. The EHRC subscribes to a gendered model of violence against women, which sees it as both a cause and consequence of wider gender inequality. We hope this report can help inform ongoing policy debate on criminal justice agencies’ response to violence against women, particularly in light of the new single equality duty which Scottish Ministers will in due course place on Scottish public authorities under powers conferred on them by the Equality Act 2010. We believe that the appropriate regulatory framework for public bodies working in this area is one of the prerequisites for further improving on Scotland’s record of identifying and tackling gender-based crime

A qualitative study of penetration testers and what they can tell us about information security in organisations

Purpose: This paper presents a qualitative study of penetration testing, the practice of attacking information systems to find security vulnerabilities and fixing them. The purpose of this paper is to understand whether and to what extent penetration testing can reveal various socio-organisational factors of information security in organisations. In doing so, the paper innovates theory by using Routine Activity Theory together with phenomenology of information systems concepts. Design/methodology/approach: The articulation of Routine Activity Theory and phenomenology emerged inductively from the data analysis. The data consists of 24 qualitative interviews conducted with penetration testers, analysed with thematic analysis. Findings: The starting assumption is that penetration testers are akin to offenders in a crime situation, dealing with targets and the absence of capable guardians. A key finding is that penetration testers described their targets as an installed base, highlighting how vulnerabilities, which make a target suitable, often emerge from properties of the existing built digital environments. This includes systems that are forgotten or lack ongoing maintenance. Moreover, penetration testers highlighted that although the testing is often predicated on planned methodologies, often they resort to serendipitous practices such as improvisation. Originality/value: This paper contributes to theory, showing how Routine Activity Theory and phenomenological concepts can work together in the study of socio-organisational factors of information security. This contribution stems from considering that much research on information security focuses on the internal actions of organisations. The study of penetration testing as a proxy of real attacks allows novel insights into socio-organisational factors of information security in organisations.</p

Connexins: synthesis, post-translational modifications, and trafficking in health and disease

Connexins are tetraspan transmembrane proteins that form gap junctions and facilitate direct intercellular communication, a critical feature for the development, function, and homeostasis of tissues and organs. In addition, a growing number of gap junction-independent functions are being ascribed to these proteins. The connexin gene family is under extensive regulation at the transcriptional and post-transcriptional level, and undergoes numerous modifications at the protein level, including phosphorylation, which ultimately affects their trafficking, stability, and function. Here, we summarize these key regulatory events, with emphasis on how these affect connexin multifunctionality in health and disease

Modelling stellar coronal magnetic fields

Our understanding of the structure and dynamics of stellar coronae has changed dramatically with the availability of surface maps of both star spots and also magnetic field vectors. Magnetic field extrapolations from these surface maps reveal surprising coronal structures for stars whose masses and hence internal structures and dynamo modes may be very different from that of the Sun. Crucial factors are the fraction of open magnetic flux (which determines the spin-down rate for the star as it ages) and the location and plasma density of closed-field regions, which determine the X-ray and radio emission properties. There has been recent progress in modelling stellar coronae, in particular the relative contributions of the field detected in the bright surface regions and the field that may be hidden in the dark star spots. For the Sun, the relationship between the field in the spots and the large scale field is well studied over the solar cycle. It appears, however, that other stars can show a very different relationship.Comment: 6pages, 4 figure

Current Star Formation in the Ophiuchus and Perseus Molecular Clouds: Constraints and Comparisons from Unbiased Submillimeter and Mid-Infrared Surveys. II

We present a census of the population of deeply embedded young stellar objects (YSOs) in the Ophiuchus molecular cloud complex based on a combination of Spitzer Space Telescope mid-infrared data from the "Cores to Disks" (c2d) legacy team and JCMT/SCUBA submillimeter maps from the COMPLETE team. We have applied a method developed for identifying embedded protostars in Perseus to these datasets and in this way construct a relatively unbiased sample of 27 candidate embedded protostars with envelopes more massive than our sensitivity limit (about 0.1 M_sun). Embedded YSOs are found in 35% of the SCUBA cores - less than in Perseus (58%). On the other hand the mid-infrared sources in Ophiuchus have less red mid-infrared colors, possibly indicating that they are less embedded. We apply a nearest neighbor surface density algorithm to define the substructure in each of the clouds and calculate characteristic numbers for each subregion - including masses, star formation efficiencies, fraction of embedded sources etc. Generally the main clusters in Ophiuchus and Perseus (L1688, NGC1333 and IC348) are found to have higher star formation efficiencies than small groups such as B1, L1455 and L1448, which on the other hand are completely dominated by deeply embedded protostars. We discuss possible explanations for the differences between the regions in Perseus and Ophiuchus, such as different evolutionary timescales for the YSOs or differences, e.g., in the accretion in the two clouds.Comment: Accepted for publication in ApJ (56 pages, 13 figures; abstract abridged). Version with full-resolution figures available at http://www.astro.uni-bonn.de/~jes/paper120.pd

Design and Development of a DSS Supporting the Integration of Crowdsourcing in Theory Testing: A Design Science Perspective

The integration of crowdsourcing in behavioral research in the IS field offers several advantages and opportunities. This paper builds on prior study, employing a design science research (DSR) paradigm to design, develop and evaluate a tool that assists researchers in adopting crowdsourcing when testing theory about behavioral phenomena. The proposed tool is based on an extensive review of literature on how theory has been tested, and a pattern model that standardizes extracted concepts, activities, processes and relationships into patterns. In particular, we discuss the architecture of the proposed tool and present two prototypes, one used for knowledge articulation by representing, extracting, organizing and acting on relevant information and the other on decision making and recommendation for the tool users. Evaluation results show the applicability and utility of the tool

The energy source of the filaments around the giant galaxy NGC1275

The brightest galaxy in the nearby Perseus cluster, NGC1275, is surrounded by a network of filaments. These were first observed through their Halpha emission but are now known to have a large molecular component with a total mass approaching 10^11Msun of gas. The filaments are embedded in hot intracluster gas and stretch over 80 kpc. They have an unusual low excitation spectrum which is well modelled by collisional heating and ionization by secondary electrons. Here we note that the surface radiative flux from the outer filaments is close to the energy flux impacting on them from particles in the hot gas. We propose that the secondary electrons within the cold filaments, which excite the observed submillimetre through UV emission, are due to the hot surrounding gas efficiently penetrating the cold gas through reconnection diffusion. Some of the soft X-ray emission seen from the filaments is then due to charge exchange, although this is insufficient to account for all the observed X-ray flux. The filaments are complex with multiphase gas. Interpenetration of hot and cold gas leads to the filaments growing in mass, at a rate of up to 100Msunpyr. The lack of soft X-ray cooling emission in cool core clusters is then due to the non-radiative cooling of hot gas on mixing with cold gas around and within the central galaxy.Comment: 7 pages, 4 figures, MNRAS in pres

The Small-Scale Physical Structure and Fragmentation Difference of Two Embedded Intermediate Mass Protostars in Orion

Intermediate-mass (IM) protostars, the bridge between the very common solar-like protostars and the more massive, but rarer, O and B stars, can only be studied at high physical spatial resolutions in a handful of clouds. In this paper, we present and analyze the continuum results from an observing campaign at the Submillimeter Array (SMA) targeting two well-studied IM protostars in Orion, NGC 2071 and L1641 S3 MMS 1. The extended SMA (eSMA) probes structure at angular resolutions up to 0".2, revealing protostellar disks on scales of ∼200 AU. Continuum flux measurements on these scales indicate that a significant amount of mass, a few tens of M_⊙, is present. Envelope, stellar, and disk masses are derived using compact, extended, and eSMA configurations and compared against spectral energy distribution fitting models. We hypothesize that fragmentation into three components occurred within NGC 2071 at an early time, when the envelopes were less than 10% of their current masses, e.g., <0.5 M. No fragmentation occurred for L1641 S3 MMS 1. For NGC 2071, evidence is given that the bulk of the envelope material currently around each source was accreted after the initial fragmentation. In addition, about 30% of the total core mass is not yet associated to one of the three sources. A global accretion model is favored and a potential accretion history of NGC 2071 is presented. It is shown that the relatively low level of fragmentation in NGC 2071 was stifled compared to the expected fragmentation from a Jeans argument. Similarly, the lack of fragmentation in L1641 S3 MMS 1 is likely due to similar arguments

On the Disruption of Star Clusters in a Hierarchical Interstellar Medium

The distribution of the number of clusters as a function of mass M and age T suggests that clusters get eroded or dispersed in a regular way over time, such that the cluster number decreases inversely as an approximate power law with T within each fixed interval of M. This power law is inconsistent with standard dispersal mechanisms such as cluster evaporation and cloud collisions. In the conventional interpretation, it requires the unlikely situation where diverse mechanisms stitch together over time in a way that is independent of environment or M. Here we consider another model in which the large scale distribution of gas in each star-forming region plays an important role. We note that star clusters form with positional and temporal correlations in giant cloud complexes, and suggest that these complexes dominate the tidal force and collisional influence on a cluster during its first several hundred million years. Because the cloud complex density decreases regularly with position from the cluster birth site, the harassment and collision rates between the cluster and the cloud pieces decrease regularly with age as the cluster drifts. This decrease is typically a power law of the form required to explain the mass-age distribution. We reproduce this distribution for a variety of cases, including rapid disruption, slow erosion, combinations of these two, cluster-cloud collisions, cluster disruption by hierarchical disassembly, and partial cluster disruption. We also consider apparent cluster mass loss by fading below the surface brightness limit of a survey. In all cases, the observed log M - \log T diagram can be reproduced under reasonable assumptions.Comment: ApJ vol. 712, March 20, 2010, 33 pages 15 figure