High-contrast imaging search for planets and brown dwarfs around the most massive stars in the solar neighborhood

There has been a long-standing discussion in the literature as to whether core accretion or disk instability is the dominant mode of planet formation. Over the last decade, several lines of evidence have been presented showing that core accretion is most likely the dominant mechanism for the close-in population of planets probed by radial velocity and transits. However, this does not by itself prove that core accretion is the dominant mode for the total planet population, since disk instability might conceivably produce and retain large numbers of planets in the far-out regions of the disk. If this is a relevant scenario, then the outer massive disks of B-stars should be among the best places for massive planets and brown dwarfs to form and reside. In this study, we present high-contrast imaging of 18 nearby massive stars of which 15 are in the B2-A0 spectral-type range and provide excellent sensitivity to wide companions. By comparing our sensitivities to model predictions of disk instability based on physical criteria for fragmentation and cooling, and using Monte Carlo simulations for orbital distributions, we find that ~85% of such companions should have been detected in our images on average. Given this high degree of completeness, stringent statistical limits can be set from the null-detection result, even with the limited sample size. We find that

Three narratives in search of a city: Researching Belfast's 'post-conflict' transitions

This paper highlights the role of narratives in expressing, shaping and ordering urban life, and as tools for analysing urban conflicts. The paper distinguishes analytically between two prominent epistemological meta-narratives in contemporary urban studies and multiple ontological narratives in a given city-in this case Belfast. The first meta-narrative represents cities as sites of deepening coercion, violence and inequality and the second sees them as engines of new forms of transnational capitalism. Both are marked by the strategy of specifying 'exemplar' or 'paradigm' cities. The core of the paper addresses how these two meta-narratives map onto and interact with, three contemporary ontological narratives of urban regeneration in Belfast. We conceive of narratives-epistemological and ontological-as analytical tools and objects of analysis but also as tools for social action for competing political and economic interests and coalitions. While in the urban studies literature Belfast is typically studied as an exemplar 'conflict city', it is now being promoted as a 'new capitalist city'. In the context of post-Agreement Belfast, we explore not only the 'pull' of exemplar narratives but also resistances to them that are linked to multiple and hybrid senses of place in the city. We conclude that any significant move beyond the exigencies of rampant commodification or recurring inter-communal antagonism must firstly, encourage new forms of grassroots place-making and, secondly, reform of Belfast's (and Northern Ireland's) fragmented governance structures. © 2013 Copyright Taylor and Francis Group, LLC.

In search of common grounds: Stitching the divided landscape of urban parks in Belfast's interface zones

Political and spatial contestation in divided cities contributes to strategies of self-defense that utilize physical and spatial settings to enable the constitution of social boundaries, borders and territories.
Urban parks that are designed to ease division through an open transitional landscape can instead facilitate further segregation through their spatial order and facility layout. This paper investigates the role of the spatial design and material landscape of integrated parks in Belfast interface areas as instruments of engagement or division. It does so by analyzing the spatial organization of the parks’ facilities and the resultant ‘social voids.’ Space, time and distance were found to be effective tools for the negotiation of privacy, the manifestation of power, and the interplay of dominance and self-confidence. In the context of a divided city, strong community-culture tends to reproduce new boundaries and territories within the shared landscape. Through user interviews and spatial analysis, this paper outlines the design principles that influence spatial behavior in the urban parks of contested urban landscapes. It argues that despite granting equal access to shared public facilities, social voids and physical gaps can instill practices of division that deepen territorial barriers, both psychologically and spatially.

Search protocols for hidden forensic objects beneath floors and within walls

The burial of objects (human remains, explosives, weapons) below or behind concrete, brick, plaster or tiling may be associated with serious crime and are difficult locations to search. These are quite common forensic search scenarios but little has been published on them to-date. Most documented discoveries are accidental or from suspect/witness testimony. The problem in locating such hidden objects means a random or chance-based approach is not advisable. A preliminary strategy is presented here, based on previous studies, augmented by primary research where new technology or applications are required. This blend allows a rudimentary search workflow, from remote desktop study, to non-destructive investigation through to recommendations as to how the above may inform excavation, demonstrated here with a case study from a homicide investigation. Published case studies on the search for human remains demonstrate the problems encountered when trying to find and recover sealed-in and sealed over locations. Established methods include desktop study, photography, geophysics and search dogs:these are integrated with new technology (LiDAR and laser scanning; photographic rectification; close quarter aerial imagery; ground-penetrating radar on walls and gamma-ray/neutron activation radiography) to propose this possible search strategy.

Search for the Return of Activity in Active Asteroid 176P/LINEAR

We present the results of a search for the reactivation of active asteroid 176P/LINEAR during its 2011 perihelion passage using deep optical observations obtained before, during, and after that perihelion passage. Deep composite images of 176P constructed from data obtained between 2011 June and 2011 December show no visible signs of activity, while photometric measurements of the object during this period also show no significant brightness enhancements similar to that observed for 176P between 2005 November and 2005 December when it was previously observed to be active. An azimuthal search for dust emission likewise reveals no evidence for directed emission (i.e., a tail, as was previously observed for 176P), while a one-dimensional surface brightness profile analysis shows no indication of a spherically symmetric coma at any time in 2011. We conclude that 176P did not in fact exhibit activity in 2011, at least not on the level on which it exhibited activity in 2005, and suggest that this could be due to the devolatization or mantling of the active site responsible for its activity in 2005.

Update: The search for the human cough receptor

Despite the best efforts of basic and applied science, the identity of the human "cough receptor" remains elusive. The attraction of identifying a single "catch all" cough receptor is obvious, although such an objective is unlikely to be realised given the concept of "cough hypersensitivity," which is now considered the most clinically relevant description of what underlies problem coughing. One means of progressing this area is to join the thinking and experimental effort of basic science and clinical research in an effective manner. Some of the best examples of cooperative and translational research over the years together with an update on the most recent work will be discussed in this article.

Spectres of Shakespeare:Ong Keng Sen’s Search: Hamlet and the Intercultural Myth

Arguably, the myth of Shakespeare is a myth of universality. Much has been written about the dramatic, thematic and ‘humanistic’ transference of Shakespeare’s works: their permeability, transcendence of cultures and histories, geographies and temporalities. Located within this debate is a belief that this universality, among other dominating factors, is founded upon the power and poeticism of Shakespeare’s language. Subsequently, if we acknowledge Frank Kermode’s assertion that “the life of the plays is the language” and “the secret (of Shakespeare’s works) is in the detail,” what then becomes of this myth of universality, and how is Shakespeare’s language ‘transferred’ across cultures? In Asian intercultural adaptations, language becomes the primary site of confrontation as issues of semantic accuracy and poetic affiliation abound. Often, the language of the text is replaced with a cultural equivalent or reconceived with other languages of the stage – song and dance, movement and music; metaphor and imagery consequently find new voices. Yet if myth is, as Roland Barthes propounds, a second-order semiotic system that is predicated upon the already constituted sign, here being language, and myth is parasitical on language, what happens to the myth of Shakespeare in these cultural re-articulations? Wherein lies the ‘universality’? Or is ‘universality’ all that it is – an insubstantial (mythical) pageant? Using Ong Keng Sen’s Search Hamlet (2002), this paper would examine the transference of myth and / as language in intercultural Shakespeares. If, as Barthes argues, myths are to be understood as metalanguages that adumbrate social hegemonies, intercultural imaginings of Shakespeare can be said to expose the hollow myth of universality yet in a paradoxical double-bind reify and reinstate this self-same myth.

Identifying Structural Breaks in Stochastic Mortality Models

In recent years, the issue of life expectancy has become of utmost importance to pension providers, insurance companies, and government bodies in the developed world. Significant and consistent improvements in mortality rates and hence life expectancy have led to unprecedented increases in the cost of providing for older ages. This has resulted in an explosion of stochastic mortality models forecasting trends in mortality data to anticipate future life expectancy and hence quantify the costs of providing for future aging populations. Many stochastic models of mortality rates identify linear trends in mortality rates by time, age, and cohort and forecast these trends into the future by using standard statistical methods. These approaches rely on the assumption that structural breaks in the trend do not exist or do not have a significant impact on the mortality forecasts. Recent literature has started to question this assumption. In this paper, we carry out a comprehensive investigation of the presence or of structural breaks in a selection of leading mortality models. We find that structural breaks are present in the majority of cases. In particular, we find that allowing for structural break, where present, improves the forecast result significantly.

Stochastic Analysis of Saltwater Intrusion in Heterogeneous Aquifers using Local Average Subdivision

This study investigates the effects of ground heterogeneity, considering permeability as a random variable, on an intruding SW wedge using Monte Carlo simulations. Random permeability fields were generated, using the method of Local Average Subdivision (LAS), based on a lognormal probability density function. The LAS method allows the creation of spatially correlated random fields, generated using coefficients of variation (COV) and horizontal and vertical scales of fluctuation (SOF). The numerical modelling code SUTRA was employed to solve the coupled flow and transport problem. The well-defined 2D dispersive Henry problem was used as the test case for the method. The intruding SW wedge is defined by two key parameters, the toe penetration length (TL) and the width of mixing zone (WMZ). These parameters were compared to the results of a homogeneous case simulated using effective permeability values. The simulation results revealed: (1) an increase in COV resulted in a seaward movement of TL; (2) the WMZ extended with increasing COV; (3) a general increase in horizontal and vertical SOF produced a seaward movement of TL, with the WMZ increasing slightly; (4) as the anisotropic ratio increased the TL intruded further inland and the WMZ reduced in size. The results show that for large values of COV, effective permeability parameters are inadequate at reproducing the effects of heterogeneity on SW intrusion.

Assembling a consistent set of sentences in relational probabilistic logic with stochastic independence

We examine the representation of judgements of stochastic independence in probabilistic logics. We focus on a relational logic where (i) judgements of stochastic independence are encoded by directed acyclic graphs, and (ii) probabilistic assessments are flexible in the sense that they are not required to specify a single probability measure. We discuss issues of knowledge representation and inference that arise from our particular combination of graphs, stochastic independence, logical formulas and probabilistic assessments.