1,720,965 research outputs found
ESTIMATION OF RAINBOW TROUT (ONCORHYNCHUS MYKISS) RESPIRATION RATE WITHIN A COMMERCIAL RACEWAY USING A DATA ASSIMILATION APPROACH
No full textInnovations and decrease in costs of sensors are making it possible to apply to aquaculture the concept of “Precision
Livestock Farming”, introduced in the agrifood sector in early 2000. The implementation of the “Precision Fish Farming”
(PFF) framework (Fore et. al., 2018) is likely to revolutionize the aquaculture industry, leading to a new generation of
softwares and decision support tools, based on dynamic data driven models. In a previous work (Royer et al., 2021), we
proposed a PFF based model of oxygen mass-balance for rainbow trout within a commercial raceway, showing that it is
possible to dynamically estimate hourly fish respiration rate in commercial farming condition and, on this basis, to improve
current control systems. In this study, the estimation method was improved by introducing a data assimilation procedure
(Kalman Filter) that allows one to correct the respiration rate as data acquisition goes by and, on this basis, to obtain more accurate short-term predictions of DO concentration
AN INDIVIDUAL-BASED BIOENERGETIC MODELOFRAINBOWTROUT (Onchorhynchus mykiss)
No full textIn Italy, there is a long tradition of rainbow trout (Oncorhynchus mykiss) farming, which requires high-quality and well-
oxygenated water. However, this activity negatively affects quality of downstream water in terms of several parameters,
e.g. BOD5, NH4 (Sidoruk, 2019). Royer et al. (2021) developed a novel approach for the implementation of the framework of Precision Fish Farming to efficiently control and predict short-term evolutions of concentration of dissolved oxygen in raceway and they highlighted the importance of having reliable tools concerning the temporal evolution of fish weight according to change in environmental and management conditions.
In this work, a new dynamic bioenergetic individual model of rainbow trout is presented, which enables one to simulate
the evolution of fish weight in relation to water temperature, feed ration and feed quality. Furthermore, the model allows
the estimation of oxygen consumption and ammonia excretion rates, which can be used to develop a population individual-based model in order to simulate short-term evolution of concentration of dissolved oxygen and of ammonia
Multiple Evidence for Climate Patterns Influencing Ecosystem Productivity across Spatial Gradients in the Venice Lagoon
Full text linkEffects of climatic changes in transitional ecosystems are often not linear, with some areas likely experiencing faster or more intense responses, which something important to consider in the perspective of climate forecasting. In this study of the Venice lagoon, time series of the past decade were used, and primary productivity was estimated from hourly oxygen data using a published model. Temporal and spatial patterns of water temperature, salinity and productivity time series were identified by applying clustering analysis. Phytoplankton and nutrient data from long-term surveys were correlated to primary productivity model outputs. pmax, the maximum oxygen production rate in a given day, was found to positively correlate with plankton variables measured in surveys. Clustering analysis showed the occurrence of summer heatwaves in 2008, 2013, 2015 and 2018 and three warm prolonged summers (2012, 2017, 2019) coincided with lower summer pmax values. Spatial effects in terms of temperature were found with segregation between confined and open areas, although the patterns varied from year to year. Production and respiration differences showed that the lagoon, despite seasonality, was overall heterotrophic, with internal water bodies having greater values of heterotrophy. Warm, dry years with high salinity had lower degrees of summer autotrophy
TESTING A REAL TIME WEIGHT MEASUREMENT SYSTEM IN A TROUT RACEWAY
No full textThe Precision Fish Farming framework (Fore et al. 2018) was recently applied to the online estimation of DO demand in a
trout raceway (Royer&al., 2020) Key to the implementation of this novel approach is the availability of real time or quasi
real time data concerning the evolution of the external forcings, the environmental variables within the farming systems
and the so called “animal variables”, e.g. fish size,. In this study, a commercial real-time weight monitoring system,
designed for salmon cages, was tested in a rainbow trout farm in Northern Italy, in order to monitor the weight evolution
within a raceway
DISSOLVED OXYGEN CONSUMPTION AND INTRA-TANK DISTRIBUTION OF TROUT BIOMASS
No full textPrecision fish farming (PFF) aims at improving accuracy, precision, and repeatability in farming operations by delivering
reliable decision-making support tools to farmers (Føre et al. 2018). It is centred on 1) large quantitative datasets provided from sensors which feed 2) data driven models and algorithms and finally supply 3) decision-supporting tools and smart management systems based on the Internet of Things (Banhazi et al., 2012). These datasets concern both environmental variables and fish bio-responses.
Here we focus on the dissolved oxygen (DO) flux along an 8m-wide 200m-long raceway tank for rainbow trout cultivation
located in Trentino Alto-Adige, Italy. Along the production cycle, liquid oxygen is supplied at constant rates into the
raceway. A previous assessment (Royer el al. 2021) has demonstrated that a DO transport model can be used to implement a cost-effective automatic control of oxygen supply in this fish farm, based on short-term predictions of oxygen demand.
As a step further, here we address the intra-tank spatial variability of DO, associated with a liquid oxygen supply,
fish metabolism, and atmospheric exchange. By analysing the streamwise variation of DO consumption, the biomass
distribution along the raceway can be estimated, allowing the assessment of preferential movements of fishes along the
tank. Furthermore, assessing the DO values at different downstream positions at the raceway is suitable for improving fish growth and respiration models
Digital twins for land-based aquaculture: A case study for rainbow trout (Oncorhynchus mykiss)
Full text linkThe virtual, digital counterpart of a physical object, referred as digital twin, derives from the Internet of Things (IoT), and involves real-time acquisition and processing of large data sets. A fully implemented system ultimately enables real-time and remote management, as well as the reproduction of real and forecasted scenarios. Under the emerging framework of Precision Fish Farming, which brings control-engineering principles to fish production, we set up digital twin prototypes for land-based finfish farms. The digital twin is aimed at supporting producers in optimizing feeding practices, oxygen supply and fish population management with respect to 1) fish growth performances; 2) fish welfare, and 3) environmental loads. It relies on integrated mathematical models which are fed with data from in-situ sensors and from external sources, and simulate several dynamic processes, allowing the estimation of key parameters describing the ambient environment and the fishes. A conceptual application targeted at rearing cycles of rainbow trout (Oncorhynchus mykiss) in an operational in-land aquafarm in Italy is presented. The digital twin takes into account the disparate levels of automation and control that are found within this farm, and considerations are made on preferential directions for future developments. In spite of its potential, and not only in the aquaculture sector, the development of digital twins is still at its early stage. Furthermore, Precision Fish Farming applications in land-based systems as well as targeted at rainbow trout are novel developments
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
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