1,720,994 research outputs found

    Measurement of surface respiration: An IoT approach

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    This study investigates an approach to measuring surface gas fluxes based on the Internet of Things technology. A wireless self-powered, low-cost, low- power, cloud-connected device is designed to record humidity and carbon dioxide concentrations at multiple points. The manuscript describes the concept and reali- sation of the device, the hardware chosen and the data communication chain. The manuscript also discusses a preliminary evaluation of the performances of the pro- totype in a controlled environment, together with major strengths and limitations

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The 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

    A New Procedure for Combining UAV-Based Imagery and Machine Learning in Precision Agriculture

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    Drone images from an experimental field cropped with sugar beet with a high diffusion of weeds taken from different flying altitudes were used to develop and test a machine learning method for vegetation patch identification. Georeferenced images were combined with a hue-based preprocessing analysis, digital transformation by an image embedder, and evaluation by supervised learning. Specifically, six of the most common machine learning algorithms were applied (i.e., logistic regression, k-nearest neighbors, decision tree, random forest, neural network, and support-vector machine). The proposed method was able to precisely recognize crops and weeds throughout a wide cultivation field, training from single partial images. The information has been designed to be easily integrated into autonomous weed management systems with the aim of reducing the use of water, nutrients, and herbicides for precision agriculture

    Liver resections in over-75-year-old patients: Surgical hazard or current practice?

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    Objectives: To assess the safety of hepatic resections in the very old patient by comparing the outcome in patients younger and older than 75 years. Methods: Thirty-two resections in 31 patients >= 75 years (Over-75 Group) were compared with 164 resections in 162 patients <75 years (Control Group). Indications for resection, concomitant diseases, previous abdominal surgery, type of resection, associated surgical procedures, use/length of portal clamping, intra-operative blood losses and transfusions, and length of operation were preliminarily compared. The outcome was evaluated in terms of post-operative mortality, morbidity, transfusions, and postoperative hospitalization. Results: Mean age was 76.0 +/- 2.3 years (range 75-83) in the Over-75 Group and 58.4 +/- 10.7 years (range 23-74) in the Control Group. The over-75 group included more hepatomas (43.8% vs. 26.8%, P = 0.09), chronic liver disease (31.3% vs. 28.7%, P = 0.03) and concomitant diseases (62.5% vs. 32.9%, P = 0.002). The two groups were comparable (P = n.s.) when evaluated for all other variables. The 30-day mortality rate was 3.6% in the Control Group and none in the Over-75 Group. Postoperative surgical complications occurred in 37 patients (22.6%) in the Control Group and 1 patient (3.1%) in the Over-75 Group, with statistically significant differences (P = 0.01), and incidence of medical complications was 13.4% in the Control Group and 3.1% in the Over-75 Group. Median postoperative hospitalization and transfusions were not statistically different. Conclusions: Hepatic resections in over-75-year-old patients are not a surgical hazard and may be carried out relatively safely as long as an accurate selection of the patient is performed

    Combined surgical-percutaneous approach for placement of arterial devices for hepatic chemotherapy

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    Indwelling devices for intra-arterial hepatic chemotherapy are usually implanted either surgically or percutaneously. A combined surgical-percutaneous approach to a patient with double arterial supply to the liver is presented and we suggest performing an effective hepatic chemotherapy after surgery whenever two distinct hepatic arteries are present

    Variations on the Author

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    “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

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    We 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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