This paper presents an adaptable, parallelizable method for subtracting linearly coupled noise from Advanced LIGO data. We explain the features developed to ensure that the process is robust enough ...to handle the variability present in Advanced LIGO data. In this work, we target subtraction of noise due to beam jitter, detector calibration lines, and mains power lines. We demonstrate noise subtraction over the entirety of the second observing run, resulting in increases in sensitivity comparable to those reported in previous targeted efforts. Over the course of the second observing run, we see a 30% increase in Advanced LIGO sensitivity to gravitational waves from a broad range of compact binary systems. We expect the use of this method to result in a higher rate of detected gravitational-wave signals in Advanced LIGO data.
PurposeVideo game players, equipped with image capturing and rendering features, are taking photographs within digital worlds. This study examines video game photography as a documentary practice. By ...considering the experiences of a gamer-turned-photographer, this study offers an initial synthesis of this new document phenomenon and provides considerations for categorizing such photos.Design/methodology/approachTo discover the attributes of video game photography, this study utilized an auto-hermeneutic approach with self-interviewing and picture-sorting techniques. The resulting data were analyzed using interpretative phenomenological analysis.FindingsWithout tangible artifacts to commemorate gaming experiences, photographs empower the player to document and artistically reconstruct moments from purely digital worlds. The three themes from this study's findings – that video game photographs act as (1) vehicles for storytelling, (2) creative trophies, and (3) aesthetic tokens – reveal how personally meaningful documents emerge from this medium. Furthermore, the findings uncover the fuzzy boundaries between play, artwork, and documentation.Practical implicationsThis study explores techniques for categorizing in-game photographs and eliciting gameplay memories. The methods outlined may assist video game researchers, conservators, and archivists with organizing photographs as context materials.Originality/valueBy considering the lived experiences between one individual and their video game photographs, this study expands document theory into the underrepresented hobby of video games.
PurposeSome virtual, immersive stories are filled with documents that users must locate and interact with to experience a narrative. Exploring a new area of inquiry in the information science field, ...this study focuses on individuals' experiences with documents in a particular 3D storytelling world.Design/methodology/approachUsing a qualitative approach, this study examined user interactions with virtual documents to better understand the relationship between information behavior and narrative spaces. This study employed observations of users in a story-rich world, followed by semistructured interviews using virtual artifacts and stimulated recall.FindingsUsing an interpretative phenomenological analysis, this study found that (1) environmental and personal influences, (2) the search and the narrative experience and (3) expectation and confirmation events surround a user's experiences with documents in storytelling worlds. These influences and experiences determine the user's relationship with these documents, which may be considered narrative ephemera – objects that a user accumulates to create and structure a story. This model of narrative ephemera depicts the user's search for narrative cadence, fulfillment of competence needs and visions of story events or the user's own lived experiences. Individuals may experience these phenomena from a single document, shifting back and forth between the designers' intentions and the users' own realities.Originality/valueThis study represents a first attempt to investigate information behavior in a distributed narrative space: a virtual world filled with documents. This study reveals that commonly employed information behavior theories, as well as literary and motivation theories, may be well suited for investigating story worlds. Continued research in this area of inquiry may benefit educators as well as designers of digital stories.
Purpose
The purpose of this paper is to provide an overview of the literature on digital games designed or adapted for information literacy instruction, as well as practical design recommendations.
...Design/methodology/approach
The paper presents an analysis of a compiled set of peer-reviewed articles on games in the provision of information literacy instruction published between 2013 and 2018, categorized by game mechanics utilized.
Findings
Application of the inclusion criteria led to 12 papers considered relevant. Synthesis of the papers suggests that although studies indicate positive outcomes for information literacy games, such games continue to rely on transcription of declarative tasks to digital environments.
Originality/value
While previous literature reviews provide summaries on information literacy digital games, this paper not only presents an up-to-date review but also provides step-by-step instructions and worked examples for aligning information literacy learning mechanics with game mechanics.
We anticipate the first direct detections of gravitational waves (GWs) with Advanced LIGO and Virgo later this decade. Though this groundbreaking technical achievement will be its own reward, a still ...greater prize could be observations of compact binary mergers in both gravitational and electromagnetic channels simultaneously. During Advanced LIGO and Virgo's first two years of operation, 2015 through 2016, we expect the global GW detector array to improve in sensitivity and livetime and expand from two to three detectors. We model the detection rate and the sky localization accuracy for binary neutron star (BNS) mergers across this transition. We have analyzed a large, astrophysically motivated source population using real-time detection and sky localization codes and higher-latency parameter estimation codes that have been expressly built for operation in the Advanced LIGO/Virgo era. We show that for most BNS events, the rapid sky localization, available about a minute after a detection, is as accurate as the full parameter estimation. We demonstrate that Advanced Virgo will play an important role in sky localization, even though it is anticipated to come online with only one-third as much sensitivity as the Advanced LIGO detectors. We find that the median 90% confidence region shrinks from ~500 deg super(2) in 2015 to ~200 deg super(2) in 2016. A few distinct scenarios for the first LIGO/Virgo detections emerge from our simulations.
ABSTRACT Advanced ground-based gravitational-wave (GW) detectors begin operation imminently. Their intended goal is not only to make the first direct detection of GWs, but also to make inferences ...about the source systems. Binary neutron-star mergers are among the most promising sources. We investigate the performance of the parameter-estimation (PE) pipeline that will be used during the first observing run of the Advanced Laser Interferometer Gravitational-wave Observatory (aLIGO) in 2015: we concentrate on the ability to reconstruct the source location on the sky, but also consider the ability to measure masses and the distance. Accurate, rapid sky localization is necessary to alert electromagnetic (EM) observatories so that they can perform follow-up searches for counterpart transient events. We consider PE accuracy in the presence of non-stationary, non-Gaussian noise. We find that the character of the noise makes negligible difference to the PE performance at a given signal-to-noise ratio. The source luminosity distance can only be poorly constrained, since the median 90% (50%) credible interval scaled with respect to the true distance is 0.85 (0.38). However, the chirp mass is well measured. Our chirp-mass estimates are subject to systematic error because we used gravitational-waveform templates without component spin to carry out inference on signals with moderate spins, but the total error is typically less than . The median 90% (50%) credible region for sky localization is ( ), with 3% (30%) of detected events localized within Early aLIGO, with only two detectors, will have a sky-localization accuracy for binary neutron stars of hundreds of square degrees; this makes EM follow-up challenging, but not impossible.
Calibration of the Advanced LIGO detectors is the quantification of the detectors’ response to gravitational waves. Gravitational waves incident on the detectors cause phase shifts in the ...interferometer laser light which are read out as intensity fluctuations at the detector output. Understanding this detector response to gravitational waves is crucial to producing accurate and precise gravitational wave strain data. Estimates of binary black hole and neutron star parameters and tests of general relativity require well-calibrated data, as miscalibrations will lead to biased results. We describe the method of producing calibration uncertainty estimates for both LIGO detectors in the first and second observing runs.
We characterize the landscape of somatic mutations-mutations occurring after fertilization-in the human brain using ultra-deep (~250×) whole-genome sequencing of prefrontal cortex from 59 donors with ...autism spectrum disorder (ASD) and 15 control donors. We observe a mean of 26 somatic single-nucleotide variants per brain present in ≥4% of cells, with enrichment of mutations in coding and putative regulatory regions. Our analysis reveals that the first cell division after fertilization produces ~3.4 mutations, followed by 2-3 mutations in subsequent generations. This suggests that a typical individual possesses ~80 somatic single-nucleotide variants present in ≥2% of cells-comparable to the number of de novo germline mutations per generation-with about half of individuals having at least one potentially function-altering somatic mutation somewhere in the cortex. ASD brains show an excess of somatic mutations in neural enhancer sequences compared with controls, suggesting that mosaic enhancer mutations may contribute to ASD risk.
ABSTRACT The Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) discovered gravitational waves (GWs) from a binary black hole merger in 2015 September and may soon observe signals ...from neutron star mergers. There is considerable interest in searching for their faint and rapidly fading electromagnetic (EM) counterparts, though GW position uncertainties are as coarse as hundreds of square degrees. Because LIGO's sensitivity to binary neutron stars is limited to the local universe, the area on the sky that must be searched could be reduced by weighting positions by mass, luminosity, or star formation in nearby galaxies. Since GW observations provide information about luminosity distance, combining the reconstructed volume with positions and redshifts of galaxies could reduce the area even more dramatically. A key missing ingredient has been a rapid GW parameter estimation algorithm that reconstructs the full distribution of sky location and distance. We demonstrate the first such algorithm, which takes under a minute, fast enough to enable immediate EM follow-up. By combining the three-dimensional posterior with a galaxy catalog, we can reduce the number of galaxies that could conceivably host the event by a factor of 1.4, the total exposure time for the Swift X-ray Telescope by a factor of 2, the total exposure time for a synoptic optical survey by a factor of 2, and the total exposure time for a narrow-field optical telescope by a factor of 3. This encourages us to suggest a new role for small field of view optical instruments in performing targeted searches of the most massive galaxies within the reconstructed volumes.
PurposeWith ready access to search engines and social media platforms, the way people find image information has evolved and diversified in the past two decades. The purpose of this paper is to ...provide an overview of the literature on image information needs and behaviors.Design/methodology/approachFollowing an eight-step procedure for conducting systematic literature reviews, the paper presents an analysis of peer-reviewed work on image information needs and behaviors, with publications ranging from the years 1997 to 2019.FindingsApplication of the inclusion criteria led to 69 peer-reviewed works. These works were synthesized according to the following categories: research methods, users targeted, image types, identified needs, search behaviors and search obstacles. The reviewed studies show that people seek and use images for multiple reasons, including entertainment, illustration, aesthetic appreciation, knowledge construction, engagement, inspiration and social interactions. The reviewed studies also report that common strategies for image searches include keyword searches with short queries, browsing, specialization and reformulation. Observed trends suggest common deployment of query analysis, survey questionnaires and undergraduate participant pools to research image information needs and behavior.Originality/valueAt this point, after more than two decades of image information needs research, a holistic systematic review of the literature was long overdue. The way users find image information has evolved and diversified due to technological developments in image retrieval. By synthesizing this burgeoning field into specific foci, this systematic literature review provides a foundation for future empirical investigation. With this foundation set, the paper then pinpoints key research gaps to investigate, particularly the influence of user expertise, a need for more diverse population samples, a dearth of qualitative data, new search features and information and visual literacies instruction.
PDF
