1,721,083 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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Essays on Finance, the Environment, and Philanthropy
Get PDFThis dissertation examines environmental impacts on economic activity andfinance issues for private philanthropic foundations that might want to fund environmental efforts. The first chapter examines the effects of weather on retail activity using the lasso machine learning method to develop a flexible weather index. The second chapter presents a theoretical model showing that large investments in objectionable firms can be optimal for foundations when they yield opportunities to hedge missions. The third chapter examines tax return data for private foundations to explore intertemporal spending strategies and the tax on net investment income
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Three Essays on Environmental Economics
Get PDFThis dissertation studies three distinctive aspects of environmental economics. Chapter 1 examines the impact of smoke from fires on agriculture production of the two main U.S. cash crops: corn and soybeans. Linking smoke plume maps derived from satellite images with county-level information on corn and soybean yields, I use a panel data approach to estimate exposure to smoke plumes treating their exact frequency, timing, and location in any year as exogenous shocks. Exposure to one more day of smoke, on average, reduces yields of corn and soybeans by 0.31% and 0.23%, respectively. To help put these results in an economic context for corn and soybeans, a 10% increase in smoke relative to 2019 results in an annual loss of almost $1 billion. Chapter 2 explores the interaction relation of temperature and precipitation with number of outdoor recreation trips. Using detailed information on outdoor recreation trips in England over a four-year period, I use a semi-parametric response surface approach to examine the interaction relation. I found that although daily visits increase with temperature and decrease with rain, these gradients only have small variations across rain or temperature. Interaction of the two variables plays a small role in outdoor recreation. Chapter 3 examines how the introduction of ridesharing services such as Uber and Lyft into the U.S. urban market influences trip choice decisions. Using data from the 2009 and 2017 National Household Travel Surveys, I show that the longer Uber and Lyft have been in an urban market, the greater the increase in the 2017 survey trips that were made using taxi/rideshare services relative to the 2009 survey benchmark. This increase is driven by an upward shift that is more pronounced for short and longer distance trips than for middle distance trips and is also more pronounced on weekdays relative to weekends. Ridesharing services are shown to be a substitute for short haul bus trips, but a complement with longer rail trips
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Essays in Climate Economics
Get PDFChapter 1 of this dissertation seeks to understand the sources and nature of measurement errors in temperature variables, and how they can influence climate impact estimations. Measurement error in temperature variables is usually assumed to be “classical'' i.i.d. normal and “small''. This type of measurement error leads to attenuation bias, that is often small enough to be ignored. We show, however, that measurement errors in temperature variables are often large, distinctly non-normal, and vary systematically across space and time. The divergence between our empirical results and conventional wisdom stems from the fact that the construction of the temperature variables involves a series of steps, each of which introduces a distinct source of measurement error. This work is the first to formally characterize sources of measurement error in temperature variables and how they interact. Simulation results are provided that illustrate the influence of these sources of measurement errors on climate impact estimates. We further propose a correction method that can be used to obtain consistent estimates of the parameters of interest under the conditions identified. In Chapter 2, I zoom in to examine one particular source of measurement error: measurement error induced by using coarse data to approximate daily mean temperature. Much of the historical records from weather stations around the world reports on minimum and maximum temperature and this practice is still followed by most stations. The minimum and maximum are averaged to approximate daily mean temperature, the exposure variable most commonly used in climate impact studies. Empirically, I find substantive differences between daily mean temperatures constructed using hourly temperature data and daily minimum and maximum temperature. This single source of measurement error can easily result in a 5 to 10\% bias in estimates of the impact of daily mean temperature on an output measure of economic interest, with the direction of the bias dependent on the location and season of the year.Chapter 3 investigates climate impact models from another perspective: the representation of climate variables. The “bin” regression model has been put forward as a flexible semi-parametric method for representing a climate variable and it has emerged as the workhorse approach for empirical work (e.g., Deschênes and Greenstone, 2011). Our work is the first to formally explore econometric properties of the bin regression approach. We show that, although the bin regression approach often produces reasonable results, that the approach produces consistent parameter estimates only under very stringent and highly unlikely assumptions about the true data generating procedure. Problems with the bin regression approach are likely to be most severe in the tail bin categories, where most policy interest with respect to climate change impacts lies. We propose alternatives to bin model for the climate change impacts that produce consistent estimates and generally have better efficiency properties
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Essays in Urban and Regional Economics
Get PDFChapter 1 examines the economic consequences of expanding housing supply in productive urban cities and analyzes how residential sorting plays a role in forming a new market equilibrium. Using the newly released 2013-2017 American Community Survey data, I construct an economic model system that includes the models characterizing household residential location choices and their simultaneous spatial interactions with local labor markets, housing markets, and urban amenities across geographical areas in California. I find that, in an open economy with agglomeration effects, the positive residential sorting largely undoes what the housing legislation aims to achieve and reduces the quality of urban amenities in productive cities. Chapter 2 documents the relationship between climate amenities and locational choices in retirement. Using data from 2017 release of the American Community Survey, I construct a household residential location choice model and value climate amenities from the trade-offs among housing cost, climate amenities, and other locational attributes in a metropolitan statistical area (MSA). The results show that values of climate amenities vary with household demographic characteristics, and older households with a higher retirement income and disability have a higher marginal willingness to pay for a favorable climate. Using projected climate data, I find that over 2\% of retired households would relocate in response to this level of climate change.Chapter 3 investigates how the residential real estate market, the second-largest asset market, in the U.S. has been fundamentally changed by the advent of online real estate websites. Using data on over 50,000 completed transactions obtained from Zillow, we first look at how the availability of the Zestimate influences both listing and sales prices. The factors influencing the listing realtor's decision to hold an open house are examined, as is the role such an open house has on the sales price and sales timing. Empirical results suggest that Zestimates play an important and complex role in driving the sales process and that holding an initial open house substantially increases sales price and decreases time on the market
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Essays on Environmental Policy and Climate Change
Get PDFThese essays study environmental policy and regulation, ecosystem service valuation, and the economic impacts of climate change. Chapter 1 explores the role of coastal wetlands in reducing property damage during tropical cyclones impacting the U.S. and estimates the economic value of this protective service. Chapter 2 investigates the effectiveness of a large-scale green stimulus measure in China: a major sales tax cut for greener vehicles. Chapter 3 studies the role of extreme weather in time-use decisions in China
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