24,254 research outputs found
Modelling life cycle related and individual shape variation in biological specimens
The main purpose of this research is to develop methods for automatic
identification of biological specimens in digital photographs and drawings
held in a database. Incorporation of taxonomic drawings into a visual indexing
system has not been attempted to date. Diatoms are a single cell microscopic
algae that provide a particularly suitable case study. Identification of
diatoms is a challenging task due to the huge number of the species, blurred
boundaries between species, and life cycle related shape changes. A novel
model based on principal curves representing the life cycle related shape
variation of a number of diatom species has been developed. Our model
is suitable for reconstruction purposes, allowing us to produce drawings of a
variety of diatom shapes, thus providing a link between the photographs and
drawings. We present the classification results of photographed and drawn
specimens based on the model and compare our results to another recent system
for diatom identification. Finally, given a diatom specimen, we are able
not only to identify the species it belongs to but also to pinpoint the stage in
the life cycle it represents
The application of optical coherence tomography to image subsurface tissue structure of Antarctic krill Euphausia superba
Many small open ocean animals, such as Antarctic krill, are an important part of marine ecosystems. To discover what will happen to animals such as krill in a changing ocean, experiments are run in aquaria where conditions can be controlled to simulate water characteristics predicted to occur in the future. The response of individual animals to changing water conditions can be hard to observe, and with current observation techniques it is very difficult to follow the progress of an individual animal through its life. Optical coherence tomography (OCT) is an optical imaging technique that allows images at high resolution to be obtained from depths up to a few millimeters inside biological specimens. It is compatible with in vivo imaging and can be used repeatedly on the same specimens. In this work, we show how OCT may be applied to post mortem krill samples and how important physiological data such as shell thickness and estimates of organ volume can be obtained. Using OCT we find an average value for the thickness of krill exoskeleton to be (30±4) µm along a 1 cm length of the animal body. We also show that the technique may be used to provide detailed imagery of the internal structure of a pleopod joint and provide an estimate for the heart volume of (0.73±0.03) mm3
Bridging the biodiversity data gaps: Recommendations to meet users’ data needs
A strong case has been made for freely available, high quality data on species occurrence, in order to track changes in biodiversity. However, one of the main issues surrounding the provision of such data is that sources vary in quality, scope, and accuracy. Therefore publishers of such data must face the challenge of maximizing quality, utility and breadth of data coverage, in order to make such data useful to users. Here, we report a number of recommendations that stem from a content need assessment survey conducted by the Global Biodiversity Information Facility (GBIF). Through this survey, we aimed to distil the main user needs regarding biodiversity data. We find a broad range of recommendations from the survey respondents, principally concerning issues such as data quality, bias, and coverage, and extending ease of access. We recommend a candidate set of actions for the GBIF that fall into three classes: 1) addressing data gaps, data volume, and data quality, 2) aggregating new kinds of data for new applications, and 3) promoting ease-of-use and providing incentives for wider use. Addressing the challenge of providing high quality primary biodiversity data can potentially serve the needs of many international biodiversity initiatives, including the new 2020 biodiversity targets of the Convention on Biological Diversity, the emerging global biodiversity observation network (GEO BON), and the new Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES)
Proceedings of Abstracts Engineering and Computer Science Research Conference 2019
© 2019 The Author(s). This is an open-access work distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. For further details please see https://creativecommons.org/licenses/by/4.0/. Note: Keynote: Fluorescence visualisation to evaluate effectiveness of personal protective equipment for infection control is © 2019 Crown copyright and so is licensed under the Open Government Licence v3.0. Under this licence users are permitted to copy, publish, distribute and transmit the Information; adapt the Information; exploit the Information commercially and non-commercially for example, by combining it with other Information, or by including it in your own product or application. Where you do any of the above you must acknowledge the source of the Information in your product or application by including or linking to any attribution statement specified by the Information Provider(s) and, where possible, provide a link to this licence: http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/This book is the record of abstracts submitted and accepted for presentation at the Inaugural Engineering and Computer Science Research Conference held 17th April 2019 at the University of Hertfordshire, Hatfield, UK. This conference is a local event aiming at bringing together the research students, staff and eminent external guests to celebrate Engineering and Computer Science Research at the University of Hertfordshire. The ECS Research Conference aims to showcase the broad landscape of research taking place in the School of Engineering and Computer Science. The 2019 conference was articulated around three topical cross-disciplinary themes: Make and Preserve the Future; Connect the People and Cities; and Protect and Care
Biological Control of Weeds: Theory and Practical Application
Crop Production/Industries,
New insight in lymnaeid snails (Mollusca, Gastropoda) as intermediate hosts of Fasciola hepatica (Trematoda, Digenea) in Belgium and Luxembourg
<b>Background</b><p></p>
The present study aims to assess the epidemiological role of different lymnaeid snails as intermediate hosts of the liver fluke Fasciola hepatica in Belgium and Luxembourg.<p></p>
<b>Methods</b><p></p>
During summer 2008, 7103 lymnaeid snails were collected from 125 ponds distributed in 5 clusters each including 25 ponds. Each cluster was located in a different biogeographic area of Belgium and Luxembourg. In addition, snails were also collected in sixteen other biotopes considered as temporary wet areas. These snails were identified as Galba truncatula (n = 2474) (the main intermediate host of F. hepatica in Europe) and Radix sp. (n = 4629). Moreover, several biological and non-biological variables were also recorded from the different biotopes. DNA was extracted from each snail collected using Chelex® technique. DNA samples were screened through a multiplex PCR that amplifies lymnaeid internal transcribed spacer 2 gene sequences (500–600 bp) (acting as an internal control) and a 124 bp fragment of repetitive DNA from Fasciola sp.<p></p>
<b>Results</b><p></p>
Lymnaeid snails were found in 75 biotopes (53.2%). Thirty individuals of G. truncatula (1.31%) and 7 of Radix sp. (0.16%) were found to be positive for Fasciola sp. The seven positive Radix sp. snails all belonged to the species R. balthica (Linnaeus, 1758). Classification and regression tree analysis were performed in order to better understand links and relative importance of the different recorded factors. One of the best explanatory variables for the presence/absence of the different snail species seems to be the geographic location, whereas for the infection status of the snails no obvious relationship was linked to the presence of cattle.<p></p>
<b>Conclusions</b><p></p>
Epidemiological implications of these findings and particularly the role of R. balthica as an alternative intermediate host in Belgium and Luxembourg were discussed
Effects of climate on size structure and functioning of aquatic food webs
In aquatic food webs, the role of body size is notoriously strong. It is also well known that temperature has an effect on body size. For instance, Bergmann’s rule states that body size increases from warm to cold climates. This thesis addresses the question how climate shapes the size structure of fish and zooplankton communities, and how this affects the strength of the trophic cascade from fish to plankton. I combine three different approaches: a space-for-time substitution study of data from the 83 shallow lakes distributed along a latitudinal gradient in South America, simple mathematical models to explore climate effects on the dynamics of trophic interactions, and an experimental analysis of trophic interactions using outdoor mesocosms
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Ecophysiology, Morphology and Phylogeography of Insects in the Scotia Arc
The Scotia Arc, comprising southern South America, South Georgia and the South Orkney Islands and the Antarctic Peninsula, is home to a range of understudied insect species which are constantly exposed to extreme environmental conditions. To help reduce the amount of uncertainty surrounding insect taxa evolution in the region, we aimed to elucidate the evolutionary relationships and divergence times of non-biting midges (Diptera) and beetles (Coleoptera) naturally occurring in the lands around the Scotia Arc. The main objectives here were to learn how the evolution of select species of these two orders of insects is linked to the region’s geographical history, through the use of phylogeography, and what kind of adaptations (morphological and physiological) they have developed to deal with the environmental conditions and changes, such as osmotic stress and desiccation tolerance. There was also an intrinsic objective to ascertain the taxonomy of the midge Telmatogeton magellanicus, which potentially belongs to the genera Belgica or Halirytus. The individual studies in this thesis were carried out in the British Antarctic Survey (BAS) and in field stations in Navarino Island (Chile) and the South Shetland Islands (Antarctica), with additional field work in South Georgia Island.
Habitat Characterisation and Ecophysiology: As a first step to enable the understanding of the physiological adaptations of the brachypterous midge T. magellanicus we first had to describe, in detail, its habitat. To that end, we made use of Permutational MANOVA and Similarity Percentages, through which we were able to identify the mid-tidal zone of the intertidal as its favoured habitat, while also providing details on their abundance and the fact they mostly need filamentous algae to thrive. Subsequentially, we exposed larvae of T. magellanicus to different physiological treatments and showed that they are very resistant to osmotic stress and temperature extremes, but that exposure to desiccation are one of the main dangers to their survival. In the meantime, larvae of Eretmoptera murphyi were also exposed to osmotic stress treatments, but were shown to struggle much more to deal with saline water.
Morphology: We hypothesised that the South Georgian isolate of the diving beetle Lancetes angusticollis, could have changes to its hind wing morphology, potentially causing a loss of the ability to fly. However, the wings bear only minute changes that did not enable us to correlate that to specific environmental conditions.
Phylogeography: By means of two genetic markers (COX1 and 28S) we were able to assess the phylogeographic structure of the winged Antarctic midge Parochlus steinenii, who is spread out across the Scotia Arc, with a clear split of its South American population.
This thesis shows how insects can help us understand the development of a specific region in the globe, but also shows us how much more there is left to explore in terms of the biology and evolution of insect taxa in the Scotia Arc, specially in light of the current international debates on climate change, as these are among the organisms that are the most susceptible to sudden alteration of their habitat composition.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq - Brazil) (Process no. 233923/2014-4) in collaboration with the Cambridge Trust
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