1,721,004 research outputs found
Trends in microfluidic systems for in situ chemical analysis of natural waters
Full text linkSpatially and temporally detailed measurement of ocean, river and lake chemistry is key to fully understanding the biogeochemical processes at work within them. To obtain these valuable data, miniaturised in situ chemical analysers have recently become an attractive alternative to traditional manual sampling, with microfluidic technology at the forefront of recent advances. In this short critical review we discuss the role, operation and application of in situ microfluidic analysers to measure biogeochemical parameters in natural waters. We describe recent technical developments, most notably how pumping technology has evolved to allow long-term deployments, and describe how they have been deployed in real-world situations to yield detailed, scientifically useful data. Finally, we discuss the technical challenges that still remain and the key obstacles that must be negotiated if these promising systems are to be widely adopted and used, for example, in large environmental sensor networks and on low-power underwater vehicles
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
Time series measurements from a lab-on-chip dissolved silica (DSi) sensor deployed in a glacier-fed fjord (Nuup Kangerlua, Greenland) between June and September 2019
No full textThis is a time-series record dissolved silica (DSi) collected using an in situ lab-on-chip sensor that was deployed in a glacier-fed fjord (Nuup Kangerlua) between 14th June to 13th September 2019. The sensor (along with a conductivity, temperature and depth (CTD) probe) was attached to a frame that was anchored to a cliff and submerged at an average depth of 5 m. The sensor was programmed to draw in ambient water (through 0.45 µm pore-size 13 mm diameter polyethersulfone inlet filter) and measure its DSi concentration every 12 hours. Each measurement was accompanied by the measurement of an onboard calibration standard and a blank solution (artificial seawater). During a three-month monitoring period DSi varied between 0.35 and 14.98 µM (± 0.5 μM)
Time series measurements from a lab-on-chip nitrate sensor deployed in a glacier-fed fjord (Nuup Kangerlua, Greenland) between June and September 2019
No full textThis is a time-series record of nitrate + nitrite (∑NOx) concentrations measured using an in situ lab-on-chip sensor that was deployed in a glacier-fed fjord (Nuup Kangerlua) between 14th June to 13th September 2019. The sensor (along with a conductivity, temperature and depth (CTD) probe and a silicic acid sensor) was attached to a frame that was anchored to a cliff and submerged at an average depth of 5 m. The sensor was programmed to draw in ambient water (through 0.45 µm pore-size 13 mm diameter polyethersulfone inlet filters) and measure its nitrate + nitrite concentration every 12 hours. Each measurement was accompanied by the measurement of an onboard calibration standard and a blank solution (artificial seawater). During a three-month monitoring period ∑NOx varied between 0.05 and 10.07 µM (± 0.2 μM)
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
Temperature, salinity and depth measurements from a moored CTD deployed in a glacier-fed fjord (Nuup Kangerlua, Greenland) between June and September 2019
No full textThis is time-series temperature, salinity and depth data from a conductivity, temperature and depth (CTD) probe deployed in a glacier-fed fjord (Nuup Kangerlua) between 14th June and 13th September 2019. The instrument was anchored to a cliff via a wire and submerged at an average depth of 5 m. The instrument was recorded a measurement every 10 minutes. During a three-month monitoring period salinity varied between 14.19 and 30.81, temperature varied between 0.13 and 6.91 °C and depth varied between 2.27 and 7.87 m
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