1,721,218 research outputs found
Production of ice nucleating particles (INPs) by fast growing phytoplankton
No full textThe objective of this research was to determine how physiological status and taxonomic affiliation affected the production of biogenic aerosols and atmospheric ice nucleating particles (INP). This summary dataset includes data on the growth and physiological status of Thalassiosira weissflogii and Synechococcus elongatus grown in batch culture in a marine aerosol reference tank (MART). Aerosol samples were collected from the headspace of the MART and were analyzed for their ability to act as immersion ice nuclei
Biogeochemistry of phytoplankton RuBisCO in the ocean
No full textRibulose-1,5-bisphosphate oxygenase/carboxylase (RuBisCO) is the most abundant enzyme on Earth, playing a key role in carbon fixation during oxygenic photosynthesis. Form I RuBisCO is found in marine photosynthesizers and land plants. There are different Types of Form I RuBisCO, which vary in amino acid length and composition. The objective of this research was to determine the amounts of elemental resources (C, N, S) associated with the different Types of RuBisCO found in marine phytoplankton. This was achieved by converting published protein sequence data (from UniProt KB) into elemental data for the large and small subunit proteins in RuBisCO. The results of these calculations are presented in this database for the large subunit (L), small subunit (S), and L8S8 holoenzyme of RuBisCO for marine photosynthetic organisms and representative land plants
Photophysiology of smooth cordgrass (Sporobolus alterniflorus) measured using rapid light curves
No full textSmooth cordgrass (Sporobolus alterniflorus) (previously known as Spartina alterniflora) is often the dominant intertidal plant in saltmarshes on the east coast of the United States. It is an invasive species in several locations globally, where it has been introduced accidently, or deliberately to stabilize eroding shorelines. These data present measurements of the photophysiology of photosynthesis in Sporobolus alterniflorus. Measurements were made in situ using pulse amplitude modulated (PAM) fluorescence. The data includes measurements of the quantum yield of photosystem II and rapid light curves (RLCs), which were used to determine electron transport rates (ETRs) and parameterize the relationship between ETR and photosynthetic photon flux density (PPFD). The measurements are supported by in situ environmental data, specifically measurements of PPFD and air temperature. These data have potential value to researchers interested in the physiology of saltmarsh plants and grasses, and estuarine ecologists and resource managers
Predictions of short-term rates and the expectations hypothesis
No full textThis paper emphasizes that traditional tests of the EH are based on two assumptions: the expectations hypothesis (EH) per se and an assumption about the expectations generating process (EGP) for the short-term rate. Arguing that conventional tests of the EH need to assume EGPs that may be significantly at odds with the true EGP, we investigate this possibility by analyzing the out-of-sample predictive performances of several models for predicting interest rates, including a few models which assume that the EH holds in its functional form that relates long- to short-term yields. Using US riskless yield data for a 1970–2016 monthly sample and testing methods that take into account the parameter uncertainty, the null hypothesis of an equal predictive accuracy of each model relative to the random walk alternative is hardly ever rejected at intermediate and long horizons. This confirms that, at least at a practical level, the main difficulty with the EH is represented by the effective prediction of short-term rates. We discuss the relevance of these findings for central banks’ use of forward guidance
RuBisCO and other biomolecules as ice nuclei
No full textResults from laboratory experiments investigating the ice nucleation properties under atmospheric conditions of major classes of organic compounds found in marine phytoplankton. Ice nucleation was measured in the immersion mode on compounds in their native state and after heat denaturation
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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
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