On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0×10(-21). It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203,000 years, equivalent to a significance greater than 5.1σ. The source lies at a luminosity distance of 410(-180)(+160)  Mpc corresponding to a redshift z=0.09(-0.04)(+0.03). In the source frame, the initial black hole masses are 36(-4)(+5)M⊙ and 29(-4)(+4)M⊙, and the final black hole mass is 62(-4)(+4)M⊙, with 3.0(-0.5)(+0.5)M⊙c(2) radiated in gravitational waves. All uncertainties define 90% credible intervals. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.

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The Observation of Gravitational Waves from a Binary Black Hole Merger

The theory of affordances

What Video Games Have to Teach Us about Learning and Literacy

Over the past few generations, expectations of comfort, cleanliness and convenience have altered radically, but these dramatic changes have largely gone unnoticed. This intriguing book brings together the sociology of consumption and technology to investigate the evolution of these changes, as well the social meaning of the practices themselves. Homes, offices, domestic appliances and clothes play a crucial role in our lives, but not many of us question exactly how and why we perform so many daily rituals associated with them. Showers, heating, air-conditioning and clothes washing are simply accepted as part of our normal, everyday lives, but clearly this was not always the case. When did the daily shower become de rigueur? What effect has air conditioning had on the siesta at one time an integral part of Mediterranean life and culture? This book interrogates the meaning and supposed normality of these practices and draws disturbing conclusions. There is clear evidence supporting the view that routine consumption is controlled by conceptions of normality and profoundly shaped by cultural and economic forces. Shove maintains that habits are not just changing, but are changing in ways that imply escalating and standardizing patterns of consumption. This shrewd and engrossing analysis shows just how far the social meanings and practices of comfort, cleanliness and convenience have eluded us.

Comfort, cleanliness and conveniencethe social organization ofnormality

Preface (1999) Preface (1990) 1. Subjects of Sex/Gender/Desire I. 'Women' as the Subject of Feminism II. The Compulsory Order of Sex/Gender/Desire III. Gender: The Circular Ruins of Contemporary Debate IV. Theorizing the Binary, the Unitary and Beyond V. Identity, Sex and the Metaphysics of Substance VI. Language, Power and the Strategies of Displacement 2. Prohibition, Psychoanalysis, and the Production of the Heterosexual Matrix I. Structuralism's Critical Exchange II. Lacan, Riviere, and the Strategies of Masquerade III. Freud and the Melancholia of Gender IV. Gender Complexity and the Limits of Identification V. Reformulating Prohibition as Power 3. Subversive Bodily Acts I. The Body Politics of Julia Kristeva II. Foucault, Herculine, and the Politics of Sexual Discontinuity III. Monique Wittig - Bodily Disintegration and Fictive Sex IV. Bodily Inscriptions, Performative Subversions Conclusion - From Parody to Politics

Postmodern Subjects, Postmodern BodiesThinking Fragments: Psychoanalysis, Feminism, and Postmodernism in the Contemporary WestYearning: Race, Gender, and Cultural PoliticsGender Trouble: Feminism and the Subversion of Identity

Science and mathematics are becoming computational endeavors. This fact is reflected in the recently released Next Generation Science Standards and the decision to include “computational thinking” as a core scientific practice. With this addition, and the increased presence of computation in mathematics and scientific contexts, a new urgency has come to the challenge of defining computational thinking and providing a theoretical grounding for what form it should take in school science and mathematics classrooms. This paper presents a response to this challenge by proposing a definition of computational thinking for mathematics and science in the form of a taxonomy consisting of four main categories: data practices, modeling and simulation practices, computational problem solving practices, and systems thinking practices. In formulating this taxonomy, we draw on the existing computational thinking literature, interviews with mathematicians and scientists, and exemplary computational thinking instructional materials. This work was undertaken as part of a larger effort to infuse computational thinking into high school science and mathematics curricular materials. In this paper, we argue for the approach of embedding computational thinking in mathematics and science contexts, present the taxonomy, and discuss how we envision the taxonomy being used to bring current educational efforts in line with the increasingly computational nature of modern science and mathematics.

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Defining Computational Thinking for Mathematics and Science Classrooms

We are in the midst of an explosion of emerging human-computer interaction techniques that redefine our understanding of both computers and interaction. We propose the notion of Reality-Based Interaction (RBI) as a unifying concept that ties together a large subset of these emerging interaction styles. Based on this concept of RBI, we provide a framework that can be used to understand, compare, and relate current paths of recent HCI research as well as to analyze specific interaction designs. We believe that viewing interaction through the lens of RBI provides insights for design and uncovers gaps or opportunities for future research.

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Reality-based interaction: a framework for post-WIMP interfaces

Much of the work done in the field of tangible interaction has focused on creating tools for learning; however, in many cases, little evidence has been provided that tangible interfaces offer educational benefits compared to more conventional interaction techniques. In this paper, we present a study comparing the use of a tangible and a graphical interface as part of an interactive computer programming and robotics exhibit that we designed for the Boston Museum of Science. In this study, we have collected observations of 260 museum visitors and conducted interviews with 13 family groups. Our results show that visitors found the tangible and the graphical systems equally easy to understand. However, with the tangible interface, visitors were significantly more likely to try the exhibit and significantly more likely to actively participate in groups. In turn, we show that regardless of the condition, involving multiple active participants leads to significantly longer interaction times. Finally, we examine the role of children and adults in each condition and present evidence that children are more actively involved in the tangible condition, an effect that seems to be especially strong for girls.

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Comparing the use of tangible and graphical programming languages for informal science education

Research involving tangible interaction and children has often focused on how tangibles might support or improve learning compared to more traditional methods. In this paper, we review three of our research studies involving tangible computer programming that have addressed this question in a variety of learning environments with a diverse population of children. Through these studies, we identify situations in which tangible interaction seems to offer advantages for learning; however, we have also identify situations in which tangible interaction proves less useful and an alternative interaction style provides a more appropriate medium for learning. Thus, we advocate for a hybrid approach--one that offers teachers and learners the flexibility to select the most appropriate interaction style to meet the needs of a specific situation.

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Tangible interaction and learning: the case for a hybrid approach

This paper describes a new technique for implementing educational programming languages using tangible interface technology. It emphasizes the use of inexpensive and durable parts with no embedded electronics or power supplies. Students create programs in offline settings---on their desks or on the floor---and use a portable scanning station to compile their code. We argue that languages created with this approach offer an appealing and practical alternative to text-based and visual languages for classroom use. In this paper we discuss the motivations for our project and describe the design and implementation of two tangible programming languages. We also describe an initial case study with children and outline future research goals.

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Michael S. Horn

Papers

Defining Computational Thinking for Mathematics and Science Classrooms

Reality-based interaction: a framework for post-WIMP interfaces

Comparing the use of tangible and graphical programming languages for informal science education

Tangible interaction and learning: the case for a hybrid approach

Designing tangible programming languages for classroom use