GALEX Detection of Shock Breakout in Type IIP Supernova PS1-13arp: Implications for the Progenitor Star Wind

We present the GALEX detection of a UV burst at the time of explosion of an optically normal supernova (SN) IIP (PS1-13arp) from the Pan-STARRS1 survey at z = 0.1665. The temperature and luminosity of the UV burst match the theoretical predictions for shock breakout in a red supergiant (RSG), but with a duration a factor of similar to 50 longer than expected. We compare the NUV light curve of PS1-13arp to previous GALEX detections of SNe IIP and find clear distinctions that indicate that the UV emission is powered by shock breakout, and not by the subsequent cooling envelope emission previously detected in these systems. We interpret the similar to 1 day duration of the UV signal with a shock breakout in the wind of an RSG with a pre-explosion mass-loss rate of similar to 10(-3) M-circle dot yr(-1). This mass-loss rate is enough to prolong the duration of the shock breakout signal, but not enough to produce an excess in the optical plateau light curve or narrow emission lines powered by circumstellar interaction. This detection of nonstandard, potentially episodic high mass loss in an RSG SN progenitor has favorable consequences for the prospects of future wide-field UV surveys to detect shock breakout directly in these systems, and provide a sensitive probe of the pre-explosion conditions of SN progenitors.

Forensic analysis of wooden safety matches - A case study

In this case, an individual was suspected of attempting to burn materials potentially relating to a murder case. A number of spent and unspent matches were seized at the scene by police for forensic examination. Coincidentally, a police raid at the suspect's house revealed a number of matchboxes, all of the same brand, containing matches that had a visual similarity to those recovered at the scene. Stable Isotope Profiling (SIP) was used to assess whether matches could either be distinguished or shown to be indistinguishable by 13C and 2H isotopic composition. These results were then compared to those from the X-ray diffraction (XRD) analysis of match heads and microscopy of the wood. SIP showed the scene matches and seized matches to be different, which was confirmed by XRD and microscopy analyses.

Sporting Justice: An Arbitrator's Perspective

Drawing on my experience of a number of sports dispute resolution tribunals in the UK and Ireland (such as Sports Resolutions UK; Just Sport Ireland; the Football Association of Ireland’s Disciplinary Panel and the Gaelic Athletic Association’s Dispute Resolution Authority) I intend to use this paper to review the legal arguments typically made in sports-related arbitrations. These points of interest can be summarised as a series of three questions: the fairness question; the liability question; the penalty question.

In answer to the fairness question, the aim is to give a brief outline on best practice in establishing a "fair" sports disciplinary tribunal. The answer, I believe, is always twofold in nature: first, and to paraphrase Lord Steyn in R v Secretary of State For The Home Department, Ex Parte Daly [2001] UKHL 26 at [28] "in law, context is everything" – translated into the present matter, this means that in sports disciplinary cases, the more serious the charges against the individual (in terms of reputational damage, economic impact and/or length of sanction); the more tightly wrapped the procedural safeguards surrounding any subsequent disciplinary hearing must be. A fair disciplinary system will be discussed in the context of the principles laid down in Article 8 of the World Anti-Doping Code which, in effect, acts as sport’s Article 6 of the ECHR on a right to a fair trial.

Following on from the above, in the 60 or so sports arbitrations that I have heard, there are two further points of interest. First, the claim before the arbitral panel will often be framed in an argument that, for various reasons of substantive and procedural irregularity, the sanction imposed on the appellant should be quashed ("the liability"). Second, and in alternative, that the sanction imposed was wholly disproportionate ("the penalty").

The liability issue usually breaks down into two further questions. First, what is the nature of the legal duty upon a sports body in exercising its disciplinary remit? Second, to what extent does a de novo hearing on appeal cure any apparent defects in a hearing of first instance? The first issue often results in an arbitral panel debating the contra preferentum approach to the interpretation of a contested rule i.e., the sports body’s rules in question are so ambiguous that they should be interpreted in a manner to the detriment of the rule maker and in favour of the appellant. On the second matter, it now appears to be a general principle of sports law, administrative law and even human rights law that even if a violation of the principles of natural justice takes place at the first instance stage of a disciplinary process, they may be cured on de novo appeal. Authority for this approach can be found at the Court of Arbitration for Sport and in particular in CAS 2009/A/1920 FK Pobeda, Aleksandar Zabrcanec, Nikolce Zdraveski v UEFA at para 87.

The question on proportionality asks what, aside from precedent found within the decisions of the sports body in question, are the general legal principles against which a sanction by a sports disciplinary body can be benchmarked in order to ascertain whether it is disproportionate in length or even irrational in nature?

On the matter of (dis)proportionality of sanction, the debate is usually guided by the authority in Bradley v the Jockey Club [2004] EWHC 2164 (QB) and affirmed at [2005] EWCA Civ 1056. The Bradley principles on proportionality of sports-specific sanctions, recently cited with approval at the Court of Arbitration for Sport, will be examined in this presentation.

Finally, an interesting application of many of the above principles (and others such as the appropriate standard of proof in sports disciplinary procedures) can be made to recent match-fixing or corruption related hearings held by the British Horse Racing Authority, the integrity units of snooker and tennis, and at the Court of Arbitration for Sport.

PS1-10afx at z = 1.388: Pan-STARRS1 Discovery of a New Type of Superluminous Supernova

We present the Pan-STARRS1 discovery of PS1-10afx, a unique hydrogen-deficient superluminous supernova (SLSN) at redshift z = 1.388. The light curve peaked at z P1 = 21.7 mag, making PS1-10afx comparable to the most luminous known SNe, with Mu = -22.3 mag. Our extensive optical and near-infrared observations indicate that the bolometric light curve of PS1-10afx rose on the unusually fast timescale of ~12 days to the extraordinary peak luminosity of 4.1 × 1044 erg s-1 (M bol = -22.8 mag) and subsequently faded rapidly. Equally important, the spectral energy distribution is unusually red for an SLSN, with a color temperature of ~6800 K near maximum light, in contrast to previous hydrogen-poor SLSNe, which are bright in the ultraviolet (UV). The spectra more closely resemble those of a normal SN Ic than any known SLSN, with a photospheric velocity of ~11, 000 km s-1 and evidence for line blanketing in the rest-frame UV. Despite the fast rise, these parameters imply a very large emitting radius (gsim 5 × 1015 cm). We demonstrate that no existing theoretical model can satisfactorily explain this combination of properties: (1) a nickel-powered light curve cannot match the combination of high peak luminosity with the fast timescale; (2) models powered by the spindown energy of a rapidly rotating magnetar predict significantly hotter and faster ejecta; and (3) models invoking shock breakout through a dense circumstellar medium cannot explain the observed spectra or color evolution. The host galaxy is well detected in pre-explosion imaging with a luminosity near L*, a star formation rate of ~15 M ⊙ yr-1, and is fairly massive (~2 × 1010 M ⊙), with a stellar population age of ~108 yr, also in contrast to the young dwarf hosts of known hydrogen-poor SLSNe. PS1-10afx is distinct from known examples of SLSNe in its spectra, colors, light-curve shape, and host galaxy properties, suggesting that it resulted from a different channel than other hydrogen-poor SLSNe.

Experimental and discrete element modelling of cohesive iron ore fines

In this study, the behaviour of iron ore fines with varying levels of adhesion was investigated using a confined compression test and a uniaxial test. The uniaxial test was conducted using the semi-automated uniaxial EPT tester in which the cohesive strength of a bulk solid is evaluated from an unconfined compression test following a period of consolidation to a pre-defined vertical stress. The iron ore fines were also tested by measuring both the vertical and circumferential strains on the cylindrical container walls under vertical loading in a separate confined compression tester - the K0 tester, to determine the lateral pressure ratio. Discrete Element Method simulations of both experiments were carried out and the predictions were compared with the experimental observations. A recently developed DEM contact model for cohesive solids, an Elasto-Plastic Adhesive model, was used. This particle contact model uses hysteretic non-linear loading and unloading paths and an adhesion parameter which is a function of the maximum contact overlap. The model parameters for the simulations are phenomenologically based to reproduce the key bulk characteristics exhibited by the solid. The simulation results show a good agreement in capturing the stress history dependent behaviour depicted by the flow function of the cohesive iron ore fines while also providing a reasonably good match for the lateral pressure ratio observed during the confined compression K0 tests. This demonstrates the potential for the DEM model to be used in the simulation of bulk handling applications.

Characterisation of the performance of sustainable grout containing bentonite for geotechnical applications

The grouts used in sealing or backfilling boreholes should ideally be selected to be compatible with the insitu field instruments installed in the borehole and also be engineered to match closely the geotechnical properties of the parent soils. A stable grout can be made using cement with various proportions of bentonite. The grout stability is very important during both the liquid and set conditions. The liquid grout fluidity should be as viscous as possible to avoid segregation, yet fluid enough to be easily pumpable and fill voids and over-break in the borehole. This paper investigates the effect of bentonite on the fresh and rheological properties of cement-based grouts in order to develop a stable grout to be used in these geotechnical situations. These properties were evaluated by the mini-slump flow, marsh cone flow time, Lombardi plate cohesion meter, static bleeding, yield stress and plastic viscosity values. Additionally, the compressive strength at 3 days, 7 days and 28 days were also investigated. The key parameters investigated were the dosages of bentonite and water-to-binder ratio (W/B). Test results showed that the dosage of bentonite had a significant effect on the fluidity, rheological properties and compressive strength of grout. The increase in the dosage of bentonite led to increasing the values of flow time, plate cohesion meter, yield stress and plastic viscosity, and reducing the mini-slump results, the static bleeding and the compressive strength at 3 days, 7 days and 28 days. Conversely, the increase in W/B led to decreasing the values of flow time, plate cohesion meter, yield stress, and plastic viscosity and the compressive strength, while increasing the mini-slump results and bleeding. Some recommendations for suitable mix proportions for use in soil boreholes are made.

CSFinder: A Cold-Start Friend Finder in Large-Scale Social Networks

Recommending users for a new social network user to follow is a topic of interest at present. The existing approaches rely on using various types of information about the new user to determine recommended users who have similar interests to the new user. However, this presents a problem when a new user joins a social network, who is yet to have any interaction on the social network. In this paper we present a particular type of conversational recommendation approach, critiquing-based recommendation, to solve the cold start problem. We present a critiquing-based recommendation system, called CSFinder, to recommend users for a new user to follow. A traditional critiquing-based recommendation system allows a user to critique a feature of a recommended item at a time and gradually leads the user to the target recommendation. However this may require a lengthy recommendation session. CSFinder aims to reduce the session length by taking a case-based reasoning approach. It selects relevant recommendation sessions of past users that match the recommendation session of the current user to shortcut the current recommendation session. It selects relevant recommendation sessions from a case base that contains the successful recommendation sessions of past users. A past recommendation session can be selected if it contains recommended items and critiques that sufficiently overlap with the ones in the current session. Our experimental results show that CSFinder has significantly shorter sessions than the ones of an Incremental Critiquing system, which is a baseline critiquing-based recommendation system.

Locations of peculiar supernovae as a diagnostic of their origins

We put constraints on the properties of the progenitors of peculiar calcium-rich transients using the distribution of locations within their host galaxies. We confirm that this class of transients do not follow the galaxy stellar mass profile and are more likely to be found in remote locations of their apparent hosts. We test the hypothesis that these transients are from low-metallicity progenitors by comparing their spatial distributions with the predictions of self-consistent cosmological simulations that include star formation and chemical enrichment. We find that while metal-poor stars and our transient sample show a consistent preference for large offsets, metallicity alone cannot explain the extreme cases. Invoking a lower age limit on the progenitor helps to improve the match, indicating these events may result from a very old metal-poor population. We also investigate the radial distribution of globular cluster systems, and show that they too are consistent with the class of calcium-rich transients. Because photometric upper limits exist for globular clusters for some members of the class, a production mechanism related to the dense environment of globular clusters is not favoured for the calcium-rich events. However, the methods developed in this paper may be used in the future to constrain the effects of low metallicity on radially distant core-collapse events or help establish a correlation with globular clusters for other classes of peculiar explosions.

Self-regulated Shocks in Massive Star Binary Systems

In an early-type, massive star binary system, X-ray bright shocks result from the powerful collision of stellar winds driven by radiation pressure on spectral line transitions. We examine the influence of the X-rays from the wind-wind collision shocks on the radiative driving of the stellar winds using steady-state models that include a parameterized line force with X-ray ionization dependence. Our primary result is that X-ray radiation from the shocks inhibits wind acceleration and can lead to a lower pre-shock velocity, and a correspondingly lower shocked plasma temperature, yet the intrinsic X-ray luminosity of the shocks, L X, remains largely unaltered, with the exception of a modest increase at small binary separations. Due to the feedback loop between the ionizing X-rays from the shocks and the wind driving, we term this scenario as self-regulated shocks. This effect is found to greatly increase the range of binary separations at which a wind-photosphere collision is likely to occur in systems where the momenta of the two winds are significantly different. Furthermore, the excessive levels of X-ray ionization close to the shocks completely suppress the line force, and we suggest that this may render radiative braking less effective. Comparisons of model results against observations reveal reasonable agreement in terms of log (L X/L bol). The inclusion of self-regulated shocks improves the match for kT values in roughly equal wind momenta systems, but there is a systematic offset for systems with unequal wind momenta (if considered to be a wind-photosphere collision).

Footprints in the sand: a persistent spatial impression of fishing in a mobile groundfish assemblage

Fishing is well known to curtail the size distribution of fish populations. This paper reports the discovery of small-scale spatial patterns in length appearing in several exploited species of Celtic Sea demersal 'groundfish'. These patterns match well with spatial distributions of fishing activity, estimated from vessel monitoring records taken over a period of 6 years, suggesting that this 'mobile' fish community retains a persistent impression of local-scale fishing pressure. An individual random-walk model of fish movement best matched these exploitation 'footprints' with individual movement rates set to <35 km per year. We propose that Celtic Sea groundfish may have surprisingly low movement rates for much of the year, such that fishing impact is spatially heterogeneous and related to local fishing intensity.

2P/Encke, the Taurid complex NEOs and the Maribo and Sutter's Mill meteorites

Aims. 2P/Encke is a short period comet that was discovered in 1786 and has been extensively observed and studied for more than 200years. The Taurid meteoroid stream has long been linked with 2P/Encke owing to a good match of their orbital elements, even thoughthe comet’s activity is not strong enough to explain the number of observed meteors. Various small near-Earth objects (NEOs) havebeen discovered with orbits that can be linked to 2P/Encke and the Taurid meteoroid stream. Maribo and Sutter’s Mill are CM typecarbonaceous chondrite that fell in Denmark on January 17, 2009 and April 22, 2012, respectively. Their pre-atmospheric orbits placethem in the middle of the Taurid meteoroid stream, which raises the intriguing possibility that comet 2P/Encke could be the parentbody of CM chondrites.
Methods. To investigate whether a relationship between comet 2P/Encke, the Taurid complex associated NEOs, and CM chondritesexists, we performed photometric and spectroscopic studies of these objects in the visible wavelength range. We observed 2P/Enckeand 10 NEOs on August 2, 2011 with the FORS instrument at the 8.2 m Very Large Telescope on Cerro Paranal (Chile).
Results. Images in the R filter, used to investigate the possible presence of cometary activity around the nucleus of 2P/Encke andthe NEOs, show that no resolved coma is present. None of the FORS spectra show the 700 nm absorption feature due to hydratedminerals that is seen in the CM chondrite meteorites. All objects show featureless spectra with moderate reddening slopes at λ < 800nm. Apart for 2003 QC10 and 1999 VT25, which show a flatter spectrum, the spectral slope of the observed NEOs is compatible withthat of 2P/Encke. However, most of the NEOs show evidence of a silicate absorption in lower S/N data at λ > 800 nm, which is notseen in 2P/Encke, which suggests that they are not related.
Conclusions. Despite similar orbits, we find no spectroscopic evidence for a link between 2P/Encke, the Taurid complex NEOs andthe Maribo and Sutter’s Mill meteorites. However, we cannot rule out a connection to the meteorites either, as the spectral differencesmay be caused by secondary alteration of the surfaces of the NEOs. 

Finite-element investigation of cold-formed steel portal frames in fire

This paper presents the results of a full-scale site fire test performed on a cold-formed steel portal frame building with semi-rigid joints. The purpose of the study is to establish a performance-based approach for the design of such structures in fire boundary conditions. In the full-scale site fire test, the building collapsed asymmetrically at a temperature of 714°C. A non-linear elasto-plastic finite-element shell model is described and is validated against the results of the full-scale test. A parametric study is presented that highlights the importance of in-plane restraint from the side rails in preventing an outwards sway failure for both a single portal and full building geometry model. The study also demonstrates that the semi-rigidity of the joints should be taken into account in the design. The single portal and full building geometry models display a close match to site test results with failure at 682°C and 704°C, respectively. A design case is described in accordance with Steel Construction Institute design recommendations. The validated single portal model is tested with pinned bases, columns protected, realistic loading and rafters subject to symmetric uniform heating in accordance with the ISO 834 standard fire curve; failure occurs at 703°C.

Cascaded multimodal biometric recognition framework

A practically viable multi-biometric recognition system should not only be stable, robust and accurate but should also adhere to real-time processing speed and memory constraints. This study proposes a cascaded classifier-based framework for use in biometric recognition systems. The proposed framework utilises a set of weak classifiers to reduce the enrolled users' dataset to a small list of candidate users. This list is then used by a strong classifier set as the final stage of the cascade to formulate the decision. At each stage, the candidate list is generated by a Mahalanobis distance-based match score quality measure. One of the key features of the authors framework is that each classifier in the ensemble can be designed to use a different modality thus providing the advantages of a truly multimodal biometric recognition system. In addition, it is one of the first truly multimodal cascaded classifier-based approaches for biometric recognition. The performance of the proposed system is evaluated both for single and multimodalities to demonstrate the effectiveness of the approach.

Operators for Similarity Search: Semantics, Techniques and Usage Scenarios

This book provides a comprehensive tutorial on similarity operators. The authors systematically survey the set of similarity operators, primarily focusing on their semantics, while also touching upon mechanisms for processing them effectively.

The book starts off by providing introductory material on similarity search systems, highlighting the central role of similarity operators in such systems. This is followed by a systematic categorized overview of the variety of similarity operators that have been proposed in literature over the last two decades, including advanced operators such as RkNN, Reverse k-Ranks, Skyline k-Groups and K-N-Match. Since indexing is a core technology in the practical implementation of similarity operators, various indexing mechanisms are summarized. Finally, current research challenges are outlined, so as to enable interested readers to identify potential directions for future investigations.

In summary, this book offers a comprehensive overview of the field of similarity search operators, allowing readers to understand the area of similarity operators as it stands today, and in addition providing them with the background needed to understand recent novel approaches.

Weak and strong disjunction in possibilistic ASP

Possibilistic answer set programming (PASP) unites answer set programming (ASP) and possibilistic logic (PL) by associating certainty values with rules. The resulting framework allows to combine both non-monotonic reasoning and reasoning under uncertainty in a single framework. While PASP has been well-studied for possibilistic definite and possibilistic normal programs, we argue that the current semantics of possibilistic disjunctive programs are not entirely satisfactory. The problem is twofold. First, the treatment of negation-as-failure in existing approaches follows an all-or-nothing scheme that is hard to match with the graded notion of proof underlying PASP. Second, we advocate that the notion of disjunction can be interpreted in several ways. In particular, in addition to the view of ordinary ASP where disjunctions are used to induce a non-deterministic choice, the possibilistic setting naturally leads to a more epistemic view of disjunction. In this paper, we propose a semantics for possibilistic disjunctive programs, discussing both views on disjunction. Extending our earlier work, we interpret such programs as sets of constraints on possibility distributions, whose least specific solutions correspond to answer sets.