1,805 research outputs found

    Measuring Our Ignorance, One Book at a Time: New Indicators of Technological Change, 1909-1949

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    We present new indicators of U.S. technological change for the period 1909-49 based on information in the Library of Congress’ catalogue. We use these indicators to estimate the connections between technological change and economic activity, and to investigate the relationship between fluctuations in innovative activity and the Great Depression. Although we do find links between technological change, output and productivity, our results suggest that the slowdown in technological progress in the early 1930s did not contribute significantly to the Great Depression. On the other hand, the remarkable acceleration in innovations after 1934 did play a role in the recovery.Technical Change, Productivity, the Great Depression

    Volumes of Evidence - Examining Technical Change Last Century Through a New Lens

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    Although technical change is central in much of modern economics, traditional measures of it are, for a number of reasons, flawed. We discuss in this paper new indicators based on data drawn from the MARC records of the Library of Congress on the number of new technology titles in various fields published in the United States over the course of the last century. These indicators, we argue, overcome many of the shortcomings associated with patents, research and development expenditures, innovation counts, and productivity figures. We find, among other things, the following: the pattern and nature of technical change described by our indicators is, on the whole, consistent with that of other measures; they represent innovation not diffusion; a strong causal relationship between our indicators and changes in TFP and output per capita; innovations in some sub-groups have had a greater impact on output and productivity than others and, moreover, the key players have changed over time. Our indicators can be used to shed light on number of important issues including the empirical relationship between technology shocks and employment, the role of technology in cross-country productivity differences, and the part played by technological change in growing skills premia in the U.S. during the last few decades.Business Cycles, Technical change, productivity, measurement

    Gun Violence, Policing, and Young Communities of Color

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    Young people of color are leading the response to recent instances of gun violence. Young people do not all experience gun violence at the same rate nor do they feel its consequences evenly. Our research on young adults between the ages of 18 and 29 years old highlights the very different experiences young people have with guns, gun violence, and policing across racial and ethnic groups

    Critical-thinking disposition and profile of critical-thinking disposition for postprofessional graduate athletic training students

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    New Media and Youth Political Action

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    To rigorously consider the impact of new media on the political and civic behavior of young people, The MacArthur Research Network on Youth and Participatory Politics (YPP) developed and fielded one of the first large-scale, nationally representative studies of new media and politics among young people. The two principal researchers for the survey component of the YPP, Cathy J. Cohen of the University of Chicago and Joseph Kahne of Mills College, oversaw a research team that surveyed nearly 3,000 respondents between the ages of 15 and 25 years of age. Unlike any prior study of youth and new media, this study included large numbers of black, Latino, and Asian American respondents, which allows for unique and powerful statistical comparisons across race with a focus on young people.Until now there has been limited opportunity and data available to comprehensively explore the relationship between new media and the politics of young people. One of the few entities to engage in this type of rigorous analysis has been the Pew Internet and American Life Project. The YPP study expands on this field-leading work by including an extensive battery of items addressing participatory politics and adequate numbers of participants from different racial and ethnic groups, thus allowing for analysis of how different groups of young people were engaged with new media in the political realm.The YPP study findings suggest that fundamental changes in political expectations and practices may be occurring -- especially for youth. The analysis of the data collected reveals that youth are taking advantage of an expanded set of participatory practices in the political realm in ways that amplify their voice and sometimes their influence, thus increasing the ways young people participate in political life. The YPP researchers label this expanded set of opportunities and actions participatory politics

    Holocene-Neogene volcanism in northeastern Australia: chronology and eruption history

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    Quaternary and late Neogene volcanism is widespread in northeastern Australia, producing at least 397 eruptions covering more than 20,000 km2, including at least 20 flows over 50 km long. Despite this abundance of young volcanism, before this study numerous eruptions had tentative ages or were undated, and the area requires a comprehensive evaluation of eruption patterns through time. To help address these issues we applied multi-collector ARGUS-V 40Ar/39Ar geochronology to determine the age of four of the younger extensive flows: Undara (160 km long, 189 ± 4/4 ka; 2σ, with full analytical/external uncertainties), Murronga (40 km long, 153 ± 5/5 ka), Toomba (120 km long, 21 ± 3/3 ka), and Kinrara (55 km long, 7 ± 2/2 ka). Verbal traditions of the Gugu Badhun Aboriginal people contain features that may potentially describe the eruption of Kinrara. If the traditions do record this eruption, they would have been passed down for 230 ± 70 generations – a period of time exceeding the earliest written historical records. To further examine north Queensland volcanism through time we compiled a database of 337 ages, including 179 previously unpublished K-Ar and radiocarbon results. The compiled ages demonstrate that volcanic activity has occurred without major time breaks since at least 9 Ma. The greatest frequency of eruptions occurred in the last 2 Ma, with an average recurrence interval of <10–22 ka between eruptions. Activity was at times likely more frequent than these calculations indicate, as the geochronologic dataset is incomplete, with undated eruptions, and intraplate volcanism is often episodic. The duration, frequency, and youthfulness of activity indicate that north Queensland volcanism should be considered as potentially still active, and there are now two confirmed areas of Holocene volcanism in eastern Australia – one at each end of the continent. More broadly, our data provides another example of 40Ar/39Ar geochronology applied to Holocene and latest Pleistocene mafic eruptions, further demonstrating that this method has the ability to examine eruptions and hazards at the youngest volcanoes on Earth

    Conditioning an additive functional of a markov chain to stay non-negative. I, Survival for a long time

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    Let (X-t)(t >= 0) be a continuous-time irreducible Markov chain on a finite state space E, let v be a map v: E -> R \ {0}, and let (phi(t))(t >= 0) be an additive functional defined by phi(t) = integral(0)(t)(X-s) ds. We consider the case in which the process (phi(t))(t >= 0) is oscillating and that in which (phi(t))(t >= 0) has a negative drift. In each of these cases, we condition the process (X-t, phi(t))(t >= 0) on the event that (phi(t))(t >= 0) is nonnegative until time T and prove weak convergence of the conditioned process as T -> infinity
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