70 research outputs found
Shock absorbing reception surfaces for collecting fruit during the mechanical harvesting of citrus
Damage to fresh citrus caused by impact of fruits onto collecting surfaces has restricted the adoption of mechanical harvesting. Two different experiments were carried out: investigating free-falling citrus and investigating the shock absorbing capacity of various surfaces. In free-falling experiment damage to mandarin, orange and lemon was studied. Three collecting surfaces were studied: a concrete floor, an elevated canvas provided with a frame and wheels, and a concrete floor covered with a shock absorbing canvases. Three dropping heights were used. In the shock absorbing experiment, an electronic sphere and a triaxial accelerometer were used to measure the shock capacity of seven receiving surfaces: earth, earth covered with a shock absorbing canvas, earth covered with weeds, earth covered with a mulch and an elevated canvas provided with a frame and wheels. The elevated canvases had a higher shock absorbing capacity compared to the other surfaces (260 m s−2 maximum acceleration compared with 1753 m s−2 to 2772 m s−2). Weeds, mulch and the shock absorbing canvases showed significantly higher shock absorbing capacity than the bare earth. Also, the shock absorbing canvas covering the concrete floor reduce impact and fruit damage (1866 m s−2 maximum acceleration compared to 2477 m s−2). Citrus damage susceptibility during harvest depended on variety. Weeds, mulch and shock absorbing canvases were shown to reduce impact when they cover earth during the mechanical harvesting of citrus. Elevated canvases could be used as collection systems for the mechanical harvesting of fresh citrus.This study was funded by the Ministerio de Ciencia e Innovacion (research project RTA2009-00118-C02-02) and FEDER. The authors are most grateful to the following collaborators: Maria del Mar Lopez Quevedo, Montano Perez, Juan Jose Pena and Angel Perez.Ortiz Sánchez, MC.; Blasco, J.; Balasch Parisi, S.; Torregrosa Mira, A. (2011). Shock absorbing reception surfaces for collecting fruit during the mechanical harvesting of citrus. Biosystems Engineering. 110(1):2-9. https://doi.org/10.1016/j.biosystemseng.2011.05.006S29110
Strengthening the health surveillance of marine mammals in the waters of metropolitan France by monitoring strandings
peer reviewedMonitoring the health status of marine mammals is a priority theme that France aims to develop with the other European Union Member States in the next two years, in the context of the Marine Strategy Framework Directive. With approximately 5,000 km of coastline and for nearly ten years, France has been recording an average of 2,000 strandings per year, which are monitored by the National Stranding Network, managed by Pelagis, the observatory for the conservation of marine mammals from La Rochelle University and the French National Center for Scientific Research. Since 1972, this network has successively evolved from spatial and temporal faunistic description to, nowadays, the detection of major causes of mortality. It now aims to carry out epidemiological studies on a population scale. Thus, a strategy to strengthen the monitoring of marine mammals’ health status based on stranding data has been developed. This strategy will allow for a more accurate detection of anthropogenic cause of death as well as those of natural origin. It will allow the monitoring of time trends and geographical differences of diseases associated with conservation and public health issues while ensuring the early detection of emerging and/or zoonotic diseases of importance. It will also allow a better assessment of the consequences of human activities on these animal populations and on the environment. Thus, this strategy is fully in line with the “One Health” approach which implies an integrated vision of public, animal and environmental health. It is broken down into four surveillance modalities: (1) general event-based surveillance (GES); (2) programmed surveillance (PS); (3) specific event-based surveillance (SES); (4) and in the longer term, syndromic surveillance (SyS). This article describes the French strategy as well as these different surveillance modalities, the levels of examinations and the associated sampling protocols and finally, the method of standardisation of the data collected. The objective is to present the strategy developed at the French level in order to integrate it into a future strategy shared at the European level to standardise practices and especially complementary analysis, necessary for a better evaluation of the health status of these mobile marine species
The effect of a multi-target protocol on cetacean detection and abundance estimation in aerial surveys
This work has been funded by the French ministry in charge of the environment (Ministére de la Transition Écologique et Solidaire).A double-platform protocol was implemented in the Bay of Biscay and English Channel during the SCANS-III survey (2016). Two observation platforms using different protocols were operating on board a single aircraft: the reference platform (Scans), targeting cetaceans, and the ‘Megafauna’ platform, recording all the marine fauna visible at the sea surface (jellyfish to seabirds). We tested for a potential bias in small cetacean detection and density estimation when recording all marine fauna. At a small temporal scale (30 s, roughly 1.5 km), our results provided overall similar perception probabilities for both platforms. Small cetacean perception was higher following the detection of another cetacean within the previous 30 s in both platforms. The only prior target that decreased small cetacean perception during the subsequent 30 s was seabirds, in the Megafauna platform. However, at a larger scale (study area), this small-scale perception bias had no effect on the density estimates, which were similar for the two protocols. As a result, there was no evidence of lower performance regarding small cetacean population monitoring for the multi-target protocol in our study area. Because our study area was characterized by moderate cetacean densities and small spatial overlap of cetaceans and seabirds, any extrapolation to other areas or time requires caution. Nonetheless, by permitting the collection of cost-effective quantitative data for marine fauna, anthropogenic activities and marine litter at the sea surface, the multi-target protocol is valuable for optimizing logistical and financial resources to efficiently monitor biodiversity and study community ecology.Publisher PDFPeer reviewe
Towards a better characterisation of deep-diving whales’ distributions by using prey distribution model outputs?
In habitat modelling, environmental variables are assumed to be proxies of lower trophic levels
distribution and by extension, of marine top predator distributions. More proximal variables,
such as potential prey fields, could refine relationships between top predator
distributions and their environment. In situ data on prey distributions are not available over
large spatial scales but, a numerical model, the Spatial Ecosystem And POpulation DYnamics
Model (SEAPODYM), provides simulations of the biomass and production of zooplankton
and six functional groups of micronekton at the global scale. Here, we explored whether
generalised additive models fitted to simulated prey distribution data better predicted deepdiver
densities (here beaked whales Ziphiidae and sperm whales Physeter macrocephalus)
than models fitted to environmental variables. We assessed whether the combination of
environmental and prey distribution data would further improve model fit by comparing their
explanatory power. For both taxa, results were suggestive of a preference for habitats associated
with topographic features and thermal fronts but also for habitats with an extended
euphotic zone and with large prey of the lower mesopelagic layer. For beaked whales, no
SEAPODYM variable was selected in the best model that combined the two types of variables,
possibly because SEAPODYM does not accurately simulate the organisms on which
beaked whales feed on. For sperm whales, the increase model performance was only marginal.
SEAPODYM outputs were at best weakly correlated with sightings of deep-diving cetaceans, suggesting SEAPODYM may not accurately predict the prey fields of these taxa.
This study was a first investigation and mostly highlighted the importance of the physiographic
variables to understand mechanisms that influence the distribution of deep-diving
cetaceans. A more systematic use of SEAPODYM could allow to better define the limits of
its use and a development of the model that would simulate larger prey beyond 1,000 m
would probably better characterise the prey of deep-diving cetaceans.En prens
New insights from metallic tracers on the ffeding ecology of common dolphins in European waters
19th Annual Conference of the European Cetacean Society and associated workshop, April 2-7, 2005, La Rochelle, FranceThe common dolphin, Delphinus delphis, is the most abundant small cetacean inhabiting the temperate waters of the northeastern Atlantic. Although its distribution can be correlated to oceanographic features, it is likely that prey abundance is the major factor in determining its occurrence and movementN
Geospatial data analysis in Russia’s geoweb
The chapter examines the role of geospatial data in Russia’s online ecosystem. Facilitated by the rise of geographic information systems and user-generated content, the distribution of geospatial data has blurred the line between physical spaces and their virtual representations. The chapter discusses different sources of these data available for Digital Russian Studies (e.g., social data and crowdsourced databases) together with the novel techniques for extracting geolocation from various data formats (e.g., textual documents and images). It also scrutinizes different ways of using these data, varying from mapping the spatial distribution of social and political phenomena to investigating the use of geotag data for cultural practices’ digitization to exploring the use of geoweb for narrating individual and collective identities online
The stranding anomaly as population indicator: the case of Harbour Porpoise <i>Phocoena phocoena</i> in North-Western Europe
Ecological indicators for monitoring strategies are expected to combine three major characteristics: ecological significance, statistical credibility, and cost-effectiveness. Strategies based on stranding networks rank highly in cost-effectiveness, but their ecological significance and statistical credibility are disputed. Our present goal is to improve the value of stranding data as population indicator as part of monitoring strategies by constructing the spatial and temporal null hypothesis for strandings. The null hypothesis is defined as: small cetacean distribution and mortality are uniform in space and constant in time. We used a drift model to map stranding probabilities and predict stranding patterns of cetacean carcasses under H-0 across the North Sea, the Channel and the Bay of Biscay, for the period 1990-2009. As the most common cetacean occurring in this area, we chose the harbour porpoise <i>Phocoena phocoena</i> for our modelling. The difference between these strandings expected under H-0 and observed strandings is defined as the stranding anomaly. It constituted the stranding data series corrected for drift conditions. Seasonal decomposition of stranding anomaly suggested that drift conditions did not explain observed seasonal variations of porpoise strandings. Long-term stranding anomalies increased first in the southern North Sea, the Channel and Bay of Biscay coasts, and finally the eastern North Sea. The hypothesis of changes in porpoise distribution was consistent with local visual surveys, mostly SCANS surveys (1994 and 2005). This new indicator could be applied to cetacean populations across the world and more widely to marine megafauna
Coronary fractional flow reserve measurements of a stenosed side branch: a computational study investigating the influence of the bifurcation angle
Causes of death of harbor porpoises (Phocoena phocoena) stranded on the northern French coastline (1995-2015)
A first assessment of the distribution, relative abundance and physiographical habitat of toothed cetaceans in the English Channel and Bay of Biscay.
- …