1,720,965 research outputs found
Analysis of Zebrafish Swimming Behavior Data using Mixed Effects Modelling
No full text<p>This analysis pipeline was used to analyze the data of Gutsfeld et al. 2024, Environmental Health Perspectives.</p>
<p>Example data to test the pipeline can be downloaded in the repository in the folder "test_data" (see repository URL below).</p>
<p>Check out our repository URL below for newest updates.</p>
Water oxygen saturation, infra-red plethysmograph readings and cardiac magnetic resonance imaging of Cancer pagurus subjected to acute severe hypoxia
No full textEdible crabs Cancer pagurus were subjected to acute severe hypoxia (15% air saturation). The cardiac responses were monitored with infra-red plethysmography (IR-PPG) and Magnetic Resonance Imaging (MRI).
The oxygen partial pressure in the water was monitored using fibre-optic oxygen sensors. "PO2_record_IR-PPG_File_1" contains the recordings relevant for animals 1 (1st run), 3, and 4. "PO2_record_IR-PPG_File_2" contains the recordings for animals 1 (2nd run) and 2.
IR-PPG recordings yielded heart rates as peak frequency. Data were also evaluated for signal peak area (integral, relative to a 1-minute minimum) and the average cyclic height as proxies for stroke volume changes.
Cardiac MRI are from 4D (i.e. time-resolved 3D) stacks of images. The time series contains the entire contraction of one cardiac cycle. The volume stack covers the entire ventricle
Seawater chemistry and cardiorespiratory performance of Cancer pagurus under warming and exposure to high CO2
No full textCancer pagurus from the North Sea were exposued to acute, step-wise warming under two levels of CO2. The exposure to either normocapnic (450 µatm CO2) or hypercapnic (1350 µatm CO2) conditions was randomized on a temperature ramp between 12 and 20°C. Steps of constant temperatures were 10 h every two °C (12, 14, 16, 18, 20°C). Seawater chemistry (temperature, salinity, ph, PCO2) was analysed at 12 and 20°C. pH is given on the free scale and used for subsequent calculation of totalk alkalinity (TA), bicarbonate concentration and dissolved inorganic carbon (DIC).
Physiological parameters were recorded over the course of a temperature ramp: Whole-animal metabolic rate (MO2) via flow-through respirometry. Heart rates (HR) via infrared photoplethysmography (IR-PPG). The integral of the raw signal of the plethysmogrpah served as a proxy for cardiac stroke volume (SV). Is was normalized to a control SV of 0.2 mL, based on literature references. The product of HR and SV equals cardiac output (CO).
The difference between logtime_MO2 and logtime is that MO2 (whole-animal metabolic rate) were sometimes recorded with an inconsistent temporal delay compared to the other parameters. For accurate correlation of the data, readers are kindly asked to use the correct logtimes for each parameter (i.e. "logtime_MO2" for "MO2" and "logtime" for the others).
In a parallel experiment, ventilatory water flow in the excurrent channel of the gill chambers, as well as haemolymph flow in the arteria sternalis and branchial veins was determined via phase-contrast magnetic resonance imaging (MRI). The lateral contractility of the heart was determined from self-gated cardiac MRI movies at 12 and 20°C during diastole and systole
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
Validation and quantification of cardiac parameters obtained by cine MR imaging in crustaceans
Get PDFIn future oceans, aquatic animals and marine ecosystems will have to cope with combined effects of ongoing warming and CO2 accumulation. This study investigated possible effects of ambient CO2 on the thermal tolerance window of the North Sea edible crab Cancer pagurus. To enhance ecological relevance, the temperature ramp was chosen to mimic daily temperature changes and allow for acclimation effects. Applied temperatures ranged from 12°C to 20°C with 2°C warming steps (within 2 hours). Temperature steps were held for 10 hours including 5 hours acclimation time and 5 h measurement time. Animals were exposed to present day normocapnia (ca. 480 μatm) and CO2 levels projected beyond 2100 (ca. 1400 μatm). Using a multi-parameter approach (measured/calculated parameters: metabolic rate, heart rate, cardiac stroke volume proxy, cardiac output proxy) enabling non-invasive recording of highly resolved and continuous data, it was investigated how aerobic metabolic rate and the cardiovascular system as key components of animal performance are modulated on a daily basis by changes in temperature and ambient CO2. As non-invasive measurements only allowed for detection of relative changes in cardiac stroke volume, an approach for non-invasive quantification using cine magnetic resonance imaging (MRI) is presented. This approach further revealed complex inner structures of the ventricle likely enhancing efficiency of the pumping mechanism.
Despite high interindividual variability, exemplary analysis of the heart rate over time could reveal, that increasing amplitudes of rhythmic patterns (representing aerobic metabolism) in response to rising temperatures mostly depended on increases at the maximum level of performance, whereas minimum levels remained stable. Additionally, temperature-dependent changes from low to high frequencies could be observed.
Beside these temperature-dependent effects, it could be shown, that CO2-concentrations around 1400 μatm can have light narcotic effects on the heart activity over time of C. pagurus. The diverse responses of the other parameters and no apparent CO2-dependent shifts in the performance response to temperature imply, that projected CO2 levels in the North Sea beyond the year 2100 do not narrow the thermal tolerance window of C. pagurus
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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