1,720,988 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Case Study of Wintertime Thundersnow in the Lake Tahoe Region
No full textOn February 14, 2019 over 1,000 lightning strikes were recorded in the Sierra Nevada and western Nevada. This was part of an atmospheric river that impacted the entire state of California and produced substantial precipitation and snowfall totals. A substantial portion of lightning strikes were coincident with snowfall and thus, this was a large-scale instance of thundersnow. Thundersnow has the potential to impact transportation and safety of life and property through heavy snow loading and lightning. This study employs the Weather Research & Forecasting Model (WRF) to recreate this event and study the synoptic and mesoscale mechanisms. By using an ingredients-based methodology the postmortem analysis of the WRF data revealed that a combination of factors contributed to this event. An upper-level jet streak was present, and the left exit region was overhead which promoted upward vertical motion over the region. A strong cold front was passing into the region which ushered in cold air and destabilized the region. Observational radar analysis revealed Narrow Cold Frontal Rainbands (NCFR’s) which were the associated lightning producing bands. The WRF model also produced NCFR’s during the time period of greatest lighting strikes. The sounding analysis revealed substantial instability for wintertime, but on par with previous studies on thundersnow. This analysis revealed mechanisms for a large scale thundersnow event in mountainous terrain which would help increase accuracy in predicting events like this in the future
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Variability in Pyroconvection During the Bootleg Fire in 2021
No full textWe examine the factors controlling the depth and vigor of pyrocumulus (pyroCu) and pyrocumulonimbus (pyroCB) clouds during the Bootleg Fire in Oregon, USA (July 2021). A combination of Next Generation Weather Radar (NEXRAD) and Geostationary Operational Environmental Satellite number 17 (GOES-17) observations are used to characterize the wildfire’s plume depth and the presence of pyroCu/Cb. These data are contextualized with High Resolution Rapid Refresh (HRRR) analysis fields to examine the thermodynamic structure of the atmosphere, and with GOES-17 Fire-Radiative Power (FRP) to characterize the fire’s forcing for plume development. Results show a range of plume depths and pyroconvective outcomes, spanning dry convective columns with maximum depths <8 km, to deep pyroCb (~13 km MSL) with precipitation and lightning. We find that the plume height relative to the convective condensation level (CCL) discriminates between pyroCu and non-pyroCu periods. For pyroCb formation, we examine FRP relative to the PyroCb Firepower Threshold (PFT), which measures how much energy is needed to initiate moist convection. We find that the FRP’s exceedance of the PFT adequately predicts pyroCb initiation, albeit not necessarily its longevity or spatial extent. We also explore the relationship between the plume rise geometry and pyroCb formation, finding that plume uprightness is associated with its ability to cross the CCL and form pyroCu/Cb. Lastly, we explore the terms Fire Convective Available Potential Energy (Fire CAPE) and Fire Convective Inhibition (Fire CIN) to describe the instability of the environment around the fire, providing insights into the fire’s proclivity to initiate pyroCu/Cb. Ultimately our results will help forecasters identify when a fire is likely to produce pyroCb
Novel sampling and modeling approaches for studying soils during and after wildfires
Full text linkWildfire transforms soil physical, chemical, and biological properties. These changes are integral soil processes in fire-prone terrestrial ecosystems around the world. Although methods for estimating fire energy and impacts aboveground have progressed in recent decades, there remain major challenges in characterizing soil heating and associated effects belowground. Overcoming these challenges is crucial for understanding how fire influences soil carbon storage, biogeochemical cycling, and ecosystem recovery after fires. The work in chapter one explores nitrogen (N) cycling in soils from a case study on the Walker Fire in Northern California, 2019. Previous work has shown that N cycling is transformed by fire but variability in the magnitude and direction of those changes makes generalizing between and within fires challenging. These studies are often complicated by the lack of prefire samples and verified control areas that did not burn. In this case study, I analyzed N cycling in samples from immediately prefire, immediately postfire, and up to nine months after the fire, in both burned and control areas. The burned sampling locations ranged from low to extreme severity. I found that in this system, fire severity and soil moisture interact to control levels of N cycling and availability. These synergistic effects would have been difficult to discern with traditional sampling designs that rely on postfire measurements and space-for-time substitutions to approximate prefire conditions because of the uncertainties inherent from spatial heterogeneity. This work increases our understanding of factors driving N cycling in Sierra Nevada forests and suggests that, when possible, this sampling design should be employed to study future fires. Chapter two proposes a model for soil heating during wildfires. Previous work has shown that the extent and duration of soil heating determines the immediate fire effects on soils. However, measuring soil temperatures during fires is logistically complicated. The resulting dearth of temperature data makes elucidating mechanisms and direct relationships between heating and fire effects challenging. In this chapter, I describe and validate a new field method, called iStakes, that addresses many of the current constraints in measuring soil temperatures. I also explain and validate a modelling framework I designed, called SheFire, which can predict soil temperature over time across soil depths during wildfires. The modeling framework also includes functions to summarize soil heating in a variety of manners and extends soil heating to biological impacts with functions that model soil organism survival at different soil depths. I use data from a case study to demonstrate the utility of iStakes and SheFire. This field method and model make studying the direct effects of fire on soil more streamlined and will help researchers characterize belowground processes that are transformed by fire
- …
