1,720,956 research outputs found
Behavioural and metabolic responses of the freshwater mussels Anodonta anatina and Unio pictorum to environmental stimuli with a focus on food and light availability
Full text linkBenthic invertebrates play a crucial role in sediment mixing, nutrient cycling, and oxygen fluxes in benthic ecosystems. Despite the broad global distribution and high abundance of unionid mussels in both lentic and lotic ecosystems, the role of their locomotion behaviour and metabolic activity on the aforementioned processes remain understudied.
In this thesis, Anodonta anatina and Unio pictorum were exposed to a range of Chlorella vulgaris concentrations between 0.5 and 20.0 mg Ash Free Dry Mass (AFDM) l-1 at 11.0, 15.0 and 19.0 ± 1.0 °C in laboratory experiments. Unionid behaviours were recorded by time-lapse photography. Mussel locomotion probability and duration, opening behaviour, posterior tip movement and the position in relation to the light source were extracted image and video analysis. The diel rhythm was assessed as well as the responses to the light intensity at ~230, 450 and 1200 lux on a horizontal light gradient. The oxygen consumption (OC) during digestion was quantified at 0.05, 6.0 and 12.0 mg of AFDM of Chlorella vulgaris l-1 at 19.0 ± 1.0 °C.
The locomotion probability was significantly higher for A. anatina, compared to U. pictorum, increased with increasing temperature (lower for 11.0 ± 1.0 °C), and decreased with increasing algal concentrations. Locomotion duration decreased with the increasing algal concentration in both species, with U. pictorum showing a shorter locomotion duration than A. anatina. Valve opening peaked at algal concentrations of 3.0 mg l-1. A contrasting locomotion pattern was recorded between the two species with A. anatina crawling on the sediment and U. pictorum breaking through the sediment with is umbo covered. Both species showed a significantly higher probability of locomotion in the absence of light and a decreasing locomotion path distance with the increasing light intensity. The specimens which moved towards the light source covered a longer distance than those which moved away. Additionally, A. anatina showed a net movement towards the light source while all activities were recorded in the absence of light. Digestion significantly contributed to unionid metabolism in both species. In addition, the mean OC rate per dry soft-tissue mass (DM) increased with the algal concentration, with A. anatina showing a significantly higher rate. In A. anatina OC DM-1 decreased with the increasing DM.
The findings are discussed in the context of eutrophication, unionid bioremediation potential, and the development of species-specific remediation models. A conceptual model developed demonstrates the ecological interactions between unionids and their environment in lentic systems
Oxygen consumption during digestion in Anodonta anatina and Unio pictorum in response to algal concentration
Full text linkAbstract The metabolic activity of unionid mussels influences the oxygen fluxes and other physical and chemical characteristics in aquatic systems. Unionid oxygen consumption rate during digestion and its dependency on food availability is understudied. In laboratory conditions, we quantified the oxygen consumption rate of Anodonta anatina and Unio pictorum in response to algal concentration—0.05, 6.0 and 12.0 mg of Ash Free Dry Mass of Chlorella vulgaris L-1 —and mussel dry soft-tissue mass at 19 ± 1C.
Following a 5-h feeding-period, the oxygen consumption rate (mg O2 h-1 ) increased with algal concentration and mussel dry mass in both species during a 2-h digestion-period. The mean oxygen consumption per gram of dry mass (mg O2 gDM-1 h-1
) increased with the algal concentration in both species. The oxygen consumption rate of A. anatina was significantly greater than that of U. pictorum at a given algal concentration. The A. anatina oxygen consumption per gram of dry mass decreased with increasing dry mass. Oxygen consumption rate during digestion shows inter-specific differences and is dependent on
food availability. The findings inform the species specific quantification of oxygen consumption, and validation is required in in situ conditions
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
