bluuebunny/crossref_metadata_2025 huggingface dataset:
Visible parts of fractal percolation
Authors: Arhosalo Ida , Järvenpää Esa , Järvenpää Maarit , Rams Michal , Shmerkin Pablo
Published: April 2012

We study dimensional properties of visible parts of fractal percolation in the plane. Provided that the dimension of the fractal percolation is at least 1, we show that, conditioned on non-extinction, almost surely all visible parts from lines are one dimensional. Furthermore, almost all of them have positive and finite Hausdorff measure. We also verify analogous results for visible parts from points. These results are motivated by an open problem on the dimensions of visible parts.
On the centre of the cyclotomic Hecke algebra of G(m, 1, 2)
Authors: McGerty Kevin
Published: April 2012

We compute the centre of the cyclotomic Hecke algebra attached to G(m, 1, 2) and show that if q ≠ 1, it is equal to the image of the centre of the affine Hecke algebra Haff2. We also briefly discuss what is known about the relation between the centre of an arbitrary cyclotomic Hecke algebra and the centre of the affine Hecke algebra of type A.
A crossed-product approach to the Cuntz–Li algebras
Authors: Kaliszewski S. , Landstad Magnus B. , Quigg John
Published: April 2012

Cuntz and Li have defined aC*-algebra associated to any integral domain, using generators and relations, and proved that it is simple and purely infinite and that it is stably isomorphic to a crossed product of a commutativeC*-algebra. We give an approach to a class ofC*-algebras containing those studied by Cuntz and Li, using the general theory ofC*-dynamical systems associated to certain semidirect product groups. Even for the special case of the Cuntz–Li algebras, our development is new.
The 1967 anti-Chinese riots in Burma and Sino–Burmese relations
Authors: Fan Hongwei
Published: April 2012

Anti-Chinese riots broke out in Rangoon on 26 June 1967. The riots, which resulted from Chinese students' defiance of the Burmese government's ban on wearing Mao badges in school, led to the deterioration of Sino–Burmese relations, symbolised by the cessation of ‘Pauk Phaw’ ties and the subsequent shift in China's foreign policy which included open intervention in Burma's civil war. The riots contributed to estranged relations between Beijing and Rangoon throughout the 1970s and 1980s despite the normalisation of bilateral ties in 1970. While the roots of the Rangoon riots lay in Burma's political economy and tensions within the local Chinese community in the context of Cold War international relations, Beijing bore primary responsibility, however, due to its export of the Cultural Revolution.
Intermarriage in colonial Malaya and Singapore: A case study of nineteenth- and early twentieth-century Roman Catholic and Methodist Asian communities
Authors: Rerceretnam Marc
Published: April 2012

Colonial race relations are regularly portrayed in light of the attempts to divide and rule colonialised Asian communities. While this article does not challenge this view, it attempts to uncover a hitherto hidden level of interaction and even intermarriage at the grassroots level in colonial Malaya and Singapore. With the exception of the various Peranakan communities that predated British rule, little to no evidence exists to show that interaction and especially intermarriage existed within early first- and second-generation migrant communities during the British colonial period. The findings show how colonial attempts to encourage a heightened sense of race and its frailties may have fallen short among some sections of the Asian community.
The Koreans in Second World War Philippines: Rumour and history
Authors: Yu Jose Lydia N.
Published: April 2012

‘Mas malupit ang mga Koreano kaysa mga Hapon’ is a rumour about Koreans in Second World War Philippines that has persisted to this day. A comparative, quantitative statement, it is roughly translated as ‘The Koreans committed more atrocities than the Japanese in Second World War Philippines’. This is a half-true memory: true, there were Koreans in the Philippines; false, they could not have committed more atrocities than the Japanese because there were very few of them, as archival evidence discussed in this article proves. If only the Koreans and their role in the war were properly discussed in Philippine textbooks, this rumour would not have persisted to this day.
Waiting for a righteous ruler: The Karen royal imaginary in Thailand and Burma
Authors: Gravers Mikael
Published: April 2012

Karen believe they are like orphans without a king and leader; royalty often appear in their myths, legends and prophecies. Buddhist Karen await the next Buddha, Ariya Metteya — preceded by a righteous Karen leader — who shall cleanse the world. This paper explores the Karen imaginary and notions of royalty as preconditions for a new era governed by Buddhist ethics that will bring peace and prosperity. This imaginary combines religion and politics in a millenarian model of the world as seen from the margins of traditional kingdoms and modern nation-states — what James Scott has termed ‘non-state spaces’. The Karen oscillate between defensive and offensive strategies, as shown in several examples. Is this imaginary a premodern phenomenon typical of marginalised minorities or perhaps also part of a modern, global imaginary of a better future? The concept of morally enchanted leadership is discussed in relation to states, nations and globalisation.
Anticipating the Arctic and the Arctic Council: pre-emption, precaution and preparedness
Authors: Dodds Klaus J.
Published: April 2012

This paper considers the role of the Arctic Council (AC) and its relationship to the future or even futures. Factors such as sea ice thinning and melting permafrost, alongside globalisation, have been cited as consequential in transforming the Arctic region. While we might be cautious about the novelty of change per se, there is a need for further debate about how the ‘future’ is imagined and put into practice. Exploring different logics, including precaution, pre-emption and preparedness, consideration is offered on how the AC attempts to anticipate the future. The contentious role of observers is investigated by way of an example, and it is concluded that there is more work to be done in terms of how different futures are assembled, mobilised and put into practice.
“Things That Are Better Concealed Than Revealed”: An Historical-Biographical Study of S. Y. Agnon's Attitude toward the Sabbatean Movement and the Traditional Jewish World
Authors: Weiss Tzahi
Published: April 2012

The literary works of many Israeli novelists and poets—among them Ḥaim Hazaz, Nathan Bistriski, Uri Ẓvi Greenberg, Amir Gilboa, Theodor Herzl, Abraham Samuel Stein, Zalman Shazar, Benyamin Shvili, and Yehoram Ben Meir—reference and develop the themes of Sabbatai Ẓvi and the Sabbatean movement; and scholars have explored the use of messianism in general and Sabbateanism in particular in Israeli literature. Yet no one has comprehensively examined the role that the Sabbatean movement plays in the oeuvre of S. Y. Agnon, the most important Hebrew writer of the twentieth century, despite numerous references to it in his work.
Is there a Godan sich?: Isaac Breuer on Kant'snoumena
Authors: Kohler George Y.
Published: April 2012

Several scholars have noted the affinity of the German Orthodox thinker Isaac Breuer (1883–1946) for the philosophy of Immanuel Kant. In fact, legend has it that Breuer had two large pictures hanging over the desk in his study: one of his grandfather Samson Raphael Hirsch and, next to it, a picture of the philosopher from Königsberg, as if in perfect harmony. Just as Maimonides, eight hundred years earlier, had tried to reconcile the biblical Moses with Aristotle in theGuide of the Perplexed, Breuer attempted to explain Hirsch's theology using Kantian terminology. But if Maimonides interpreted the Torah of Moses to fit the needs of Aristotelian metaphysics, Breuer did the opposite: he had Kant's epistemology yield to the needs of his own interpretation of the Torah.
Spatial grammar implementation: From theory to useable software
Authors: McKay Alison , Chase Scott , Shea Kristina , Chau Hau Hing
Published: April 2012

Currently available computer-aided design tools provide strong support for the later stages of product development processes where the structure and shape of the design have been fixed. Support for earlier stages of product development, when both the structure and shape of the design are still fluid, demands conceptual design tools that support designers' ways of thinking and working, and enhance creativity, for example, by offering design alternatives, difficult or not, possible without the use of such tools. The potential of spatial grammars as a technology to support such design tools has been demonstrated through experimental research prototypes since the 1970s. In this paper, we provide a review of recent spatial grammar implementations, which were presented in the Design Computing and Cognition 2010 workshop on which this paper is based, in the light of requirements for conceptual design tools and identify future research directions in both research and design education.
Multimodal spatial data access for architecture design assistance
Authors: Schultz Carl , Bhatt Mehul
Published: April 2012

We present a multimodal spatial data access framework designed to serve the informational and computational requirements of architectural design assistance systems that are intended to provide intelligent spatial decision support and analytical capabilities. The framework focuses on multiperspective semantics, qualitative and artifactual spatial abstractions, and industrial conformance and interoperability within the context of the industry foundation classes. The framework provides qualitative and cognitively adequate representational mechanisms, and the formal interpretation of the structural form of indoor spaces that are not directly provided by conventional computer-aided design based or quantitative models of space. We illustrate the manner in which these representations directly provide the spatial abstractions that are needed to enable the implementation of intelligent analytical capabilities in design assistance tools. We introduce the framework, and also provide detailed use cases that illustrate the usability of the framework and the manner of its utilization within architectural design assistance systems.
Conflict-Free Colourings of Uniform Hypergraphs With Few Edges
Authors: KOSTOCHKA A. , KUMBHAT M. , ŁUCZAK T.
Published: April 2012

A colouring of the vertices of a hypergraph is called conflict-free if each edge e of contains a vertex whose colour does not repeat in e. The smallest number of colours required for such a colouring is called the conflict-free chromatic number of , and is denoted by χCF(). Pach and Tardos proved that for an (2r − 1)-uniform hypergraph with m edges, χCF() is at most of the order of rm1/r log m, for fixed r and large m. They also raised the question whether a similar upper bound holds for r-uniform hypergraphs. In this paper we show that this is not necessarily the case. Furthermore, we provide lower and upper bounds on the minimum number of edges of an r-uniform simple hypergraph that is not conflict-free k-colourable.
Consensus Statements Regarding the Multidisciplinary Care of Limb Amputation Patients in Disasters or Humanitarian Emergencies: Report of the 2011 Humanitarian Action Summit Surgical Working Group on Amputations Following Disasters or Conflict
Authors: Knowlton Lisa Marie , Gosney James E , Chackungal Smita , Altschuler Eric , Black Lynn , Burkle Frederick M , Casey Kathleen , Crandell David , Demey Didier , Di Giacomo Lillian , Dohlman Lena , Goldstein Joshua , Gosselin Richard , Ikeda Keita , Le Roy Andree , Linden Allison , Mullaly Catherine M , Nickerson Jason , O'Connell Colleen , Redmond Anthony D , Richards Adam , Rufsvold Robert , Santos Anna LR , Skelton Terri , McQueen Kelly
Published: April 2012

Limb amputations are frequently performed as a result of trauma inflicted during conflict or disasters. As demonstrated during the 2010 earthquake in Haiti, coordinating care of these patients in austere settings is complex. During the 2011 Humanitarian Action Summit, consensus statements were developed for international organizations providing care to limb amputation patients during disasters or humanitarian emergencies. Expanded planning is needed for a multidisciplinary surgical care team, inclusive of surgeons, anesthesiologists, rehabilitation specialists and mental health professionals. Surgical providers should approach amputation using an operative technique that optimizes limb length and prosthetic fitting. Appropriate anesthesia care involves both peri-operative and long-term pain control. Rehabilitation specialists must be involved early in treatment, ideally before amputation, and should educate the surgical team in prosthetic considerations. Mental health specialists must be included to help the patient with community reintegration. A key step in developing local health systemsis the establishment of surgical outcomes monitoring. Such monitoring can optimizepatient follow-up and foster professional accountability for the treatment of amputation patients in disaster settings and humanitarian emergencies.
Work-Related Injuries and Illnesses Reported by World Trade Center Response Workers and Volunteers
Authors: Perritt Kara R. , Herbert Robin , Levin Stephen M. , Moline Jacqueline
Published: April 2012

Introduction: In 2002, the Mount Sinai Center for Occupational and Environmental Medicine, with support from the National Institute for Occupational Safety and Health (NIOSH), began coordinating the World Trade Center (WTC) Worker and Volunteer Medical Screening Program (MSP) to monitor the health of qualified WTC responders. Enrolled participants were offered a clinical examination; interviewed to collect medical, mental health, and exposure information; and requested to complete a self-administered medical questionnaire. The objective of this study was to better understand work-related injuries and illnesses sustained on-site by WTC responders.

Methods: A descriptive analysis of select data from the MSP self-administered medical questionnaire was conducted. Data collected July 2002 through April 2004 from MSP participants enrolled at the Mount Sinai clinic were reviewed using univariate statistical techniques.

Results: Records from 7,810 participants were analyzed, with most participants associated with either the construction industry (n = 2,623, 34%) or law enforcement (n = 2,036, 26%). Approximately a third of the participants (n = 2,486, 32%) reported at least one injury or illness requiring medical treatment that was sustained during WTC work/volunteer activities. Of the total 4,768 injuries/illnesses reported by these participants, respiratory complaints were most common (n = 1,350, 28%), followed by traumatic injuries excluding eye injuries (n = 961, 20%), eye injuries/ailments (n = 709, 15%), chest pain (n = 375, 8%), headaches (n = 359, 8%), skin conditions (n = 178, 4%), and digestive system conditions (n = 163, 3%). Participants reported that 36% of injuries/illnesses were treated off-site and 29% were treated on-site, with the remaining not specifying treatment location. Off-site treatment was prevalent for respiratory complaints, psychological stress, and chest pain. On-site treatment was predominate for eye injuries/ailments and traumatic injuries excluding eye injuries.

Conclusion: Study results underscore the need for rapid deployment of personal protective equipment for disaster responders and medical care stations mobilized near disaster worksites. Additionally, the results, many of which are comparable to findings from previous WTC studies where data were collected in real-time, indicate that a screening program such as the MSP may be effective in retrospectively providing general information on disaster responder demographics and work-related injuries and illnesses.
Sexual Violence Trends between 2004 and 2008 in South Kivu, Democratic Republic of Congo
Authors: Bartels Susan A. , Scott Jennifer A. , Leaning Jennifer , Kelly Jocelyn T. , Mukwege Denis , Joyce Nina R. , VanRooyen Michael J.
Published: April 2012

Introduction: For more than a decade, conflict in the Eastern Democratic Republic of Congo (DRC) has been claiming lives. Within that conflict, sexual violence has been used by militia groups to intimidate and punish communities, and to control territory. This study aimed to: (1) investigate overall frequency in number of Eastern DRC sexual assaults from 2004 to 2008 inclusive; (2) determine if peaks in sexual violence coincide with known military campaigns in Eastern DRC; and (3) study the types of violence and types of perpetrators as a function of time.

Methods: This study was a retrospective, descriptive, registry-based evaluation of sexual violence survivors presenting to Panzi Hospital between 2004 and 2008.

Results: A total of 4,311 records were reviewed. Throughout the five-year study period, the highest number of reported sexual assaults occurred in 2004, with a steady decrease in the total number of incidents reported at Panzi Hospital from 2004 through 2008. The highest peak of reported sexual assaults coincided with a known militant attack on the city of Bukavu. A smaller sexual violence peak in April 2004 coincided with a known military clash near Bukavu. Over the five-year period, the number of sexual assaults reportedly perpetrated by armed combatants decreased by 77% (p = 0.086) and the number of assaults reportedly perpetrated by non-specified perpetrators decreased by 92% (p < 0.0001). At the same time, according to the hospital registry, the number of sexual assaults reportedly perpetrated by civilians increased 17-fold (p < 0.0001). This study was limited by its retrospective nature, by the inherent selection bias of studying only survivors presenting to Panzi Hospital, and by the use of a convenience sample within Panzi Hospital.

Conclusions: After years of military rape in South Kivu Province, civilian adoption of sexual violence may be a growing phenomenon. If this is the case, the social mechanisms that prevent sexual violence will have to be rebuilt and sexual violence laws will have to be fully enforced to bring all perpetrators to justice. Proper rehabilitation and reintegration of ex-combatants may also be an important step towards reducing civilian rape in Eastern DRC.
Vulnerability and Resilience in a Group Intervention with Hospital Personnel during Exposure to Extreme and Prolonged War Stress
Authors: Palgi Yuval , Ben-Ezra Menachem , Possick Chaya
Published: April 2012

The current study presents a pilot demonstration of a new therapeutic procedure to mitigate symptoms of post-traumatic stress disorder (PTSD). The pilot took place during the Second Lebanon War. Vulnerability and resilience statements, as well as post-traumatic symptoms, were measured among special army administrative staff (SAAS) who worked in a hospital setting during extreme and prolonged war stress. All 13 soldiers in the unit studied participated in seven group therapy intervention sessions. It was hypothesized that shifting the focus of therapeutic intervention from the scenes of the events to the personal and professional narratives of preparing for the event would change the content of the soldiers’ narratives. It was believed that subtracting the number of positive statements from the number of negative statements would yield increasingly higher “resilience scores” during and after the war. It also was believed that such a change would be reflected in reduction of post-traumatic symptoms. As expected, the participants showed a decrease in vulnerability and an increase in resilience contents, as well as a decrease in traumatic symptoms during and after the war. These findings may reflect the effects of the ceasefire, the mutually supportive attitude of the participants, and the therapeutic interventions.
Kepler, CoRoT and MOST: Time-Series Photometry from Space
Authors: Kjeldsen Hans , Bedding Timothy R.
Published: April 2012

During the last 10 years we have seen a revolution in the quality and quantity of data for time-series photometry. The two satellites MOST and WIRE were the precursors for dedicated time-series missions. CoRoT (launched in 2006) has now observed more than 100,000 targets for exoplanet studies and a few hundred stars for asteroseismology, while Kepler (launched in 2009) is producing extended time-series data for years, aiming to discover Earth-size planets in or near the habitable zone. We discuss the accuracy of some of the parameters one may extract from the high-quality data from such photometric space missions, including the prospects for detecting oscillation-period changes due to real-time stellar evolution.
Long-term Monitoring with Small and Medium-sized Telescopes on the Ground and in Space
Authors: Charles P. A. , Kotze M. M. , Rajoelimanana A.
Published: April 2012

The last 20 years have seen revolutionary developments of large-scale synoptic surveys of the sky, both from the ground (e.g., the MACHO and OGLE projects, which were targetted at micro-lensing studies) and in space (e.g., the X-ray All-Sky Monitor onboard RXTE). These utilised small and medium-sized telescopes to search for transient-like events, but they have now built up a huge database of long-term light-curves, thereby enabling archival research on a wide range of objects that has not been possible hitherto. This is illustrated with examples of long time-scale optical and X-ray variability studies from the field of X-ray binary research: the high-mass BeX binaries in the SMC (using MACHO and OGLE), and the bright galactic-bulge X-ray sources (mostly LMXBs, using RXTE/ASM). As such facilities develop greater capabilities in future and at other wavelengths (developments in South Africa will be described), real-time data processing will allow much more rapid follow-up studies with the new generation of queue-scheduled large telescopes such as SALT.
Opening the 100-Year Window for Time-Domain Astronomy
Authors: Grindlay Jonathan , Tang Sumin , Los Edward , Servillat Mathieu
Published: April 2012

The large-scale surveys such as PTF, CRTS and Pan-STARRS-1 that have emerged within the past 5 years or so employ digital databases and modern analysis tools to accentuate research into Time Domain Astronomy (TDA). Preparations are underway for LSST which, in another 6 years, will usher in the second decade of modern TDA. By that time the Digital Access to a Sky Century @ Harvard (DASCH) project will have made available to the community the full sky Historical TDA database and digitized images for a century (1890–1990) of coverage. We describe the current DASCH development and some initial results, and outline plans for the “production scanning” phase and data distribution which is to begin in 2012. That will open a 100-year window into temporal astrophysics, revealing rare transients and (especially) astrophysical phenomena that vary on time-scales of a decade. It will also provide context and archival comparisons for the deeper modern surveys.
Spectroscopic Surveys
Authors: Primas Francesca
Published: April 2012

Surveys, surveys, and yet more surveys! During the last decade we have all witnessed a flourishing of imaging and spectroscopic surveys, of different sizes and over different areas of the sky. Although initially set-up for specific scientific goals, they should all share a multi-purpose flavour that can boost their impact and their exploitation by the scientific community. There are, however, fields that need more dedicated observing strategies, coordination and possibly data infrastructure in order to exploit fully these huge datasets. Time-domain astronomy is one of them. In the following, I will review the very recent developments in spectroscopic surveys, and I will report on what ESO has been involved in and has committed itself to do.
The Dynamic Radio Sky
Authors: Cordes James M.
Published: April 2012

The radio band is known to be rich in variable and transient sources, but exploration of it has only begun only in the last few years. Relevant time scales are as small as a fraction of a nanosecond (giant pulses from the Crab pulsar). Short transients (less than one second, say) have signal structure in the time-frequency plane at the very least because of interstellar plasma propagation effects (dispersion and scattering), and in some cases due to emission structure. Optimal detection requires handling a range of signal types in the time-frequency plane. Short bursts by necessity have very large effective radiation brightness temperatures associated with coherent emission processes. This paper surveys relevant source classes and summarizes propagation effects that must be considered to optimize detection in large-scale surveys. Scattering horizons for the interstellar and intergalactic media are defined, and the role of the radio band in panchromatic and multimessenger studies is discussed.
Cosmic Explosions (Optical)
Authors: Kulkarni S. R
Published: April 2012

One of the principal motivations of wide-field and synoptic surveys is the search for, and study of, transients. By transients I mean those sources that arise from the background, are detectable for some time, and then fade away to oblivion. Transients in distant galaxies need to be sufficiently bright as to be detectable, and in almost all cases those transients are catastrophic events, marking the deaths of stars. Exemplars include supernovæ and gamma-ray bursts. In our own Galaxy, the transients are strongly variable stars, and in almost all cases are at best cataclysmic rather than catastrophic. Exemplars include flares from M dwarfs, novæ of all sorts (dwarf novæ, recurrent novæ, classical novæ, X-ray novæ) and instabilities in the surface layers of stars such as S Dor or η Carina. In the nearby Universe (say out to the Virgo cluster) we have sufficient sensitivity to see novæ. In 1 I review the history of transients (which is intimately related to the advent of wide-field telescopic imaging). In 2 I summarize wide-field imaging projects, and I then review the motivations that led to the design of the Palomar Transient Factory (PTF). Next comes a summary of the astronomical returns from PTF (3), and that is followed by lessons that I have learnt from PTF (4). I conclude that, during this decade, the study of optical transients will continue to flourish (and may even accelerate as surveys at other wavelengths—notably radio, UV and X-ray—come on-line). Furthermore, it is highly likely that there will be a proliferation of highly-specialized searches for transients. Those searches may well remain active even in the era of LSST (5). I end the article by discussing the importance of follow-up telescopes for transient object studies—a topical issue, given the Portfolio Review that is being undertaken in the US.
Systematically Bridging the Gap between Novæ and Supernovæ
Authors: Kasliwal Mansi M.
Published: April 2012

Until recently, the venerable field of cosmic explosions has been plagued with a glaring six-magnitude luminosity gap between the brightest novæ and the faintest supernovæ. A key science driver of the Palomar Transient Factory was a systematic search for optical transients that are fainter, faster and rarer than supernovæ. Theorists predict a variety of mechanisms to produce transients in that “gap”, and observers have the best chance of finding them in the local universe. The talk presented the discoveries and the unique physics of cosmic explosions which bridge that gap between novæ and supernovæ. As Fig. 1 illustrates, there is now evidence of multiple, distinct populations of rare transients in the “gap”.
Supernovæ and Transients with Euclid and the European ELT
Authors: Hook Isobel
Published: April 2012

The prospects are described for studies of large samples of supernovæ and other variable objects with two proposed future facilities: (1) the European Extremely Large Telescope, a general-purpose 40-m-class ground-based optical-IR telescope, and (2) Euclid, an M-class mission within ESA's Cosmic Vision programme, primarily for cosmology. The capabilities and status of the two facilities are briefly described. Their suitability for the study of time-varying objects in general, and of supernovæ in particular, is discussed. It is shown that Euclid has the potential for NIR imaging of a few thousand Type Ia supernovæ to intermediate z, while the E-ELT will be capable of spectroscopic and classification measurements of Type Ia supernovæ to z=4.
Search for Electromagnetic Counterparts to LIGO-Virgo Candidates: Expanded Very Large Array Observations
Authors: Lazio Joseph , Keating Katie , Jenet F. A. , Kassim N. E.
Published: April 2012

This paper summarizes a search for radio-wavelength counterparts to candidate gravitational-wave events. The identification of an electromagnetic counterpart could provide a more complete understanding of a gravitational-wave event, including such characteristics as the location and the nature of the progenitor. We used the Expanded Very Large Array (EVLA) to search six galaxies which were identified as potential hosts for two candidate gravitational-wave events. We summarize our procedures and discuss preliminary results.
Spectroscopic Binaries: Towards the 100-Year Time Domain
Authors: Griffin R. F.
Published: April 2012

Good measurements of visual binary stars (position angle and angular separation) have been made for nearly 200 years. Radial-velocity observers have exhibited less patience; when the orbital periods of late-type stars in the catalogue published in 1978 are sorted into bins half a logarithmic unit wide, the modal bin is the one with periods between 3 and 10 days. The same treatment of the writer's orbits shows the modal bin to be the one between 1000 and 3000 days. Of course the spectroscopists cannot quickly catch up the 200 years that the visual observers have been going, but many spectroscopic orbits with periods of decades, and a few of the order of a century, have been published. Technical developments have also been made in ‘visual’ orbit determination, and orbits with periods of only a few days have been determined for certain ‘visual’ binaries. In principle, therefore, the time domains of visual and spectroscopic binaries now largely overlap. Overlap is essential, as it is only by combining both techniques that orbits can be determined in three dimensions, as is necessary for the important objective of determining stellar masses accurately. Nevertheless the actual overlap—objects with accurate measurements by both techniques—remains disappointingly small. There have, however, been unforeseen benefits from the observation of spectroscopic binaries that have unconventionally long orbital periods, not a few of which have proved to be interesting and significant objects in their own right. It has also been shown that binary membership is more common than was once thought (orbits have even been determined for some of the IAU standard radial-velocity stars!); a recent study of the radial velocities of K giants that had been monitored for 45 years found a binary incidence of 30%, whereas a figure of 13.7% was given as recently as 2005 for a similar group.
Sines, Steps and Droplets: Semi-parametric Bayesian Modelling of Arrival Time Series
Authors: Loredo Thomas J.
Published: April 2012

I describe ongoing work developing Bayesian methods for flexible modelling of arrival-time-series data without binning. The aim is to improve the detection and measurement of X-ray and gamma-ray pulsars and of pulses in gamma-ray bursts. The methods use parametric and semi-parametric Poisson point process models for the event rate, and by design have close connections to conventional frequentist methods that are currently used in time-domain astronomy.
Variable Stellar Object Detection and Light Curves from the Solar Mass Ejection Imager (SMEI)
Authors: Hounsell R. A. , Bode M. F. , Darnley M. J. , Harman D. J. , Hick P. P , Buffington A. , Jackson B. V. , Clover J. M. , Shafter A. W.
Published: April 2012

With the advent of surveys such as the Catalina Real-Time Transient Survey, the Palomar Transient Factory, Pan-STARRS and Gaia, the search for variable objects and transient events is rapidly accelerating. There are, however important existing data-sets from instruments not originally designed to find such events. One example of such an instrument is the Solar Mass Ejection Imager (SMEI), an all-sky space-based differential photometer which is able to produce light curves of bright objects (m ≤ 8) with a 102-minute cadence. In this paper we discuss the use of such an instrument for investigations of novæ, and outline future plans to find other variable objects with this hitherto untapped resource.
Surveying the Bright Sky
Authors: Henden Arne A.
Published: April 2012

The AAVSO is initiating a new survey of the sky. It will cover the entire visible sky, both north and south, on a daily basis, in two colours, and with a limiting magnitude of V = 17. This will be a perfect complement to LSST, but will be available years earlier and will continue into the indefinite future. The photometry will be publicly available within 24 hours through our website. Some details of the hardware and operations are described.
High Time-Resolution Astronomy on the 10-m SALT
Authors: Welsh Barry , Anderson David , McPhate Jason , Vallerga John , Siegmund Oswald H. W. , Buckley David , Gulbis Amanda , Kotze Marissa , Potter Stephen
Published: April 2012

We present a brief description of the Berkeley Visible Imaging Tube (BVIT) detector system, which is a user instrument on the 10-m Southern African Large Telescope (SALT), and include some preliminary observational results gained in mid-2011. The data show that BVIT is capable of revealing emission features occurring on time-scales of < 0.1 sec, thus opening up for the general user a window of high time-resolution astronomy at visible wavelengths.
Charting the Transient Radio Sky on Sub-Second Time-Scales with LOFAR
Authors: Hessels J. W. T. ,   the LOFAR Transients Key Science Project
Published: April 2012

The LOw Frequency ARray (LOFAR) is a radio interferometric telescope that promises to open a largely unexplored window on transient sources in the “radio sky”, from time-scales of nanoseconds to years. An important aspect of this will be the study of radio-emitting neutron stars in their various incarnations: slow pulsars, young pulsars, millisecond pulsars, magnetars, rotating radio transients, intermittent pulsars, et cetera. Pulsars and their brethren are the prototype of the more general “fast transients”: sub-second, dispersed radio bursts which point the way to extreme, and potentially still unknown, phenomena. For instance, prompt radio bursts from supernovæ and other extra-galactic bursts have been hypothesized; these could prove to be powerful cosmological probes.

This talk discussed LOFAR's impressive ability to observe pulsars and to enlarge greatly the discovery space for (even rarer) fast transients. It also presented the latest pulsar observations made during LOFAR's commissioning period. These are demonstrating powerful observing techniques that will be crucial for the next generation of radio telescopes as well as the effort to increase our understanding of the dynamic nature of the Universe.

An expanded version of the talk can be found at http://adsabs.harvard.edu/abs/2011A
Polarimetric Variability
Authors: Potter Stephen B.
Published: April 2012

I present new observations of galactic and extra-galactic polarized variable sources, and demonstrate the science that one can obtain with the appropriate instrumentation.
On Rapid Interstellar Scintillation of Quasars: PKS 1257-326 Revisited
Authors: Bignall Hayley E. , Hodgson Jeffrey A.
Published: April 2012

The line of sight towards the compact, radio loud quasar PKS 1257–326 passes through a patch of scattering plasma in the local Galactic ISM that causes large and rapid, intra-hour variations in the received flux density at centimetre wavelengths. This rapid interstellar scintillation (SS) has been occurring for at least 15 years, implying that the scattering “screen” is at least 100 AU in physical extent. Through observations of the ISS we have measured microarcsecond-scale “core shifts” in PKS 1257-326, corresponding to changing opacity during an intrinsic outburst. Recent analysis of VLA data of a sample of 128 quasars found 6 sources scintillating with a characteristic time-scale of < 2 hours, suggesting that nearby scattering screens in the ISM may have a covering fraction of a few percent. That is an important consideration for proposed surveys of the transient and variable radio sky.
Sonification of Astronomical Data
Authors: Diaz-Merced Wanda L. , Candey Robert M. , Brickhouse Nancy , Schneps Matthew , Mannone John C. , Brewster Stephen , Kolenberg Katrien
Published: April 2012

This document presentsJava-based software calledxSonifythat uses a sonification technique (the adaptation of sound to convey information) to promote discovery in astronomical data. The prototype is designed to analyze two-dimensional data, such as time-series data. We demonstrate the utility of the sonification technique with examples applied to X-ray astronomy and solar data. We have identified frequencies in theChandraX-Ray observations of EX Hya, a cataclysmic variable of the intermediate polar type. In another example we study the impact of a major solar flare, with its associated coronal mass ejection (CME), on the solar wind plasma (in particular the solar wind between the Sun and the Earth), and the Earth's magnetosphere.
Pulsars, SKA and Time-Domain Studies in the Future
Authors: Kramer Michael
Published: April 2012

Pulsars are a classical example for time-domain astronomy. Using just the precisely measured arrival time of pulses from pulsars, we can study a wide range of physics, and in particular probe the validity of theories of gravity. Despite huge success, pulsar astrophysics will completely change with the Square Kilometre Array (SKA), lifting pulsar science into a new era of time-domain astronomy. I will review the applications using pulsars and the prospects for the SKA.
The Future of the Time Domain with LSST
Authors: Walkowicz Lucianne M.
Published: April 2012

In the coming decade LSST's combination of all-sky coverage, consistent long-term monitoring and flexible criteria for event identification will revolutionize studies of a wide variety of astrophysical phenomena. Time-domain science with LSST encompasses objects both familiar and exotic, from classical variables within our Galaxy to explosive cosmological events. Increased sample sizes of known-but-rare observational phenomena will quantify their distributions for the first time, thus challenging existing theories. Perhaps most excitingly, LSST will provide the opportunity to sample previously untouched regions of parameter space. LSST will generate ‘alerts’ within 60 seconds of detecting a new transient, permitting the community to follow up unusual events in greater detail. However, follow-up will remain a challenge as the volume of transients will easily saturate available spectroscopic resources. Characterization of events and access to appropriate ancillary data (e.g. from prior observations, either in the optical or in other passbands) will be of the utmost importance in prioritizing follow-up observations. The incredible scientific opportunities and unique challenges afforded by LSST demand organization, forethought and creativity from the astronomical community. To learn more about the telescope specifics and survey design, as well as obtaining a overview of the variety of the scientific investigations that LSST will enable, readers are encouraged to look at the LSST Science Book: http://www.lsst.org/lsst/scibook. Organizational details of the LSST science collaborations and management may be found at http://www.lsstcorp.org.
Next-Generation X-Ray Astronomy
Authors: White Nicholas E.
Published: April 2012

This review of future timing capabilities in X-ray astronomy includes missions in implementation (astro-h, gems, srg and astrosat), those under study (currently nicer, athena and loft), and new technologies that may be the seeds for future missions, such as lobster-eye optics. Those missions and technologies will offer exciting new capabilities that will take X-ray Astronomy into a new generation of achievements.
Swift: Opportunities, Capabilities and Data Handling
Authors: Starling Rhaana
Published: April 2012

A focus session was held for those wanting to familiarise themselves with the Swift satellite and to consider its exploitation for specific scientific goals. An overview was presented, with questions throughout. Proposal preparation and and the automated science products from the X-ray Telescope were discussed. This account summarises the information given in the presentation and in the answers to the questions which were raised.
Gravitational Waves and Time-Domain Astronomy
Authors: Centrella Joan , Nissanke Samaya , Williams Roy
Published: April 2012

The gravitational-wave window onto the universe will open in roughly five years, when Advanced LIGO and Virgo achieve the first detections of high-frequency gravitational waves, most likely coming from compact binary mergers. Electromagnetic follow-up of these triggers, using radio, optical, and high energy telescopes, promises exciting opportunities in multi-messenger time-domain astronomy. In the decade, space-based observations of low-frequency gravitational waves from massive black hole mergers, and their electromagnetic counterparts, will open up further vistas for discovery. This two-part workshop featured brief presentations and stimulating discussions on the challenges and opportunities presented by gravitational-wave astronomy. Highlights from the workshop, with the emphasis on strategies for electromagnetic follow-up, are presented in this report.
Light Echoes
Authors: Bond Howard E. , Bentz Misty C. , Clayton Geoffrey C. , Rest Armin
Published: April 2012

The first “light echo”—scattered light from a stellar outburst arriving at the Earth months or years after the direct light from the event—was detected more than 100 years ago, around Nova Persei 1901. Renewed interest in light echoes has come from the spectacular echo around V838 Monocerotis, and from discoveries of light echoes from historical and prehistorical supernovæ in the Milky Way and Large Magellanic Cloud as well as from the 19th-century Great Eruption of η Carinae. A related technique is reverberation mapping of active galactic nuclei. This report of a workshop on Light Echoes gives an introduction to light echoes, and summarizes presentations on discoveries of light echoes from historical and prehistorical events, light and shadow echoes around R CrB stars, and reverberation mapping.
Astrotomography
Authors: Horne Keith , Baptista Raymundo , Bentz Misty C. , Steeghs Danny
Published: April 2012

Astrotomography refers to a suite of indirect imaging techniques that achieve micro-arcsecond angular resolution by measuring projections obtained from time-resolved spectroscopic observations. The projections arise from Doppler shifts, eclipses or time delays, combined with rotation of the star or binary system being imaged. At our workshop we reviewed and discussed state-of-the-art methods for imaging the surfaces and magnetic fields of rapidly rotating stars, the accretion flows in compact binary star systems and the broad emission-line regions in active galactic nuclei.
Data Management, Infrastructure and Archiving for Time-Domain Astronomy
Authors: Schade David
Published: April 2012

The workshop on Data Management issues for Time-Domain Astronomy was conceived as a forward-looking discussion of the primary issues that need to be addressed for science in the time domain. The very broad diversity of the science areas presented in the main Symposium made it clear that most of the general issues for astronomy data management—for example, large data volumes, the need for timely processing and network performance—would be pertinent in the time domain. In addition, there might be other tight time constraints on data processing when the output was required to trigger rapid follow-up observations, while science based on very long time-baselines might require careful consideration of long-term data preservation and availability issues. But broadly speaking, data management challenges in the time domain are not at variance to any significant degree with those for astronomy or data-intensive research in general. The workshop framed and debated a number of questions: What is the biggest challenge faced by future projects? How do grid and cloud computing figure in data management plans? Is the Virtual Observatory important to future projects? How are the issues of data life cycle being addressed?
Amateur Community and “Citizen Science”
Authors: Henden Arne A.
Published: April 2012

Citizen Science is the act of collecting or analyzing data by enlisting the help of volunteers who may have no specific scientific training. The workshop discussed how “Citizen Science” fits into time-domain astronomy, what the roles of such volunteers might be, and how amateur astronomers can help in the new era of surveys.
Workshop on Radio Transients
Authors: Croft Steve , Gaensler Bryan
Published: April 2012

We are entering a new era in the study of variable and transient radio sources. This workshop discussed the instruments and the strategies employed to study those sources, how they are identified and classified, how results from different surveys can be compared, and how radio observations tie in with those at other wavelengths. The emphasis was on learning what common ground there is between the plethora of on-going projects, how methods and code can be shared, and how best practices regarding survey strategy could be adopted.

The workshop featured the four topics below. Each topic commenced with a fairly brief introductory talk, which then developed into discussion. By way of preparation, participants had been invited to upload and discuss one slide per topic to a wiki ahead of the workshop.

1. Telescopes, instrumentation and survey strategy. New radio facilities and on-going projects (including upgrades) are both studying the variability of the radio sky, and searching for transients. The discussion first centred on the status of those facilities, and on projects with a time-domain focus, both ongoing and planned, before turning to factors driving choices of instrumentation, such as phased array versus single pixel feeds, the field of view, spatial and time resolution, frequency and bandwidth, depth, area, and cadence of the surveys.

2. Detection, pipelines, and classification. The workshop debated (a) the factors that influence decisions to study variability in the (u,v) plane, in images, or in catalogues, (b) whether, and how much, pipeline code could potentially be shared between one project and another, and which software packages are best for different approaches, (c) how data are stored and later accessed, and (d) how transients and variables are defined and classified.

3. Statistics, interpretation, and synthesis. It then discussed how (i) the choice of facility and strategy and (ii) detection and classification schemes influence what is seen (in terms of types of object and rates) by different surveys, (iii) how results from different surveys could be compared, and (iv) how what we know from existing surveys drives choices (i) and (ii), particularly as regards finding new classes of object.

4. Multiwavelength approaches. The workshop concluded by discussing what information is needed from wavelengths other than radio in order to classify transients and variables adequately and predict their rates as a function of topics (1), (2) and (3). It asked what the constraints are on responding to, and issuing triggers for, follow-up observations, and how that might feed back into considerations for designing our telescopes and surveys.