| 1. |
- Kesters, Jurgen, et al.
(författare)
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High-Permittivity Conjugated Polyelectrolyte Interlayers for High-Performance Bulk Heterojunction Organic Solar Cells
- 2016
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Ingår i: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 8:10, s. 6309-6314
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Tidskriftsartikel (refereegranskat)abstract
- Conjugated polyelectrolyte (CPE) interfacial layers present a powerful way to boost the I-V characteristics of organic photovoltaics. Nevertheless, clear guidelines with respect to the structure of high-performance interlayers are still lacking. In this work, impedance spectroscopy is applied to probe the dielectric permittivity of a series of polythiophene-based CPEs. The presence of ionic pendant groups grants the formation of a capacitive double layer, boosting the charge extraction and device efficiency. A counteracting effect is the diminishing affinity with the underlying photoactive layer. To balance these two effects, we found copolymer structures containing nonionic side chains to be beneficial.
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| 2. |
- Maes, Dirk, et al.
(författare)
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Integrating national Red Lists for prioritising conservation actions for European butterflies
- 2019
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Ingår i: Journal of Insect Conservation. - : Springer Science and Business Media LLC. - 1366-638X .- 1572-9753. ; 23:2, s. 301-330
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Tidskriftsartikel (refereegranskat)abstract
- Red Lists are very valuable tools in nature conservation at global, continental and (sub-) national scales. In an attempt to prioritise conservation actions for European butterflies, we compiled a database with species lists and Red Lists of all European countries, including the Macaronesian archipelagos (Azores, Madeira and Canary Islands). In total, we compiled national species lists for 42 countries and national Red Lists for 34 of these. The most species-rich countries in Europe are Italy, Russia and France with more than 250 species each. Endemic species are mainly found on the Macaronesian archipelagos and on the Mediterranean islands. By attributing numerical values proportionate to the threat statuses in the different national Red List categories, we calculated a mean Red List value for every country (cRLV) and a weighted Red List value for every species (wsRLV) using the square root of the country’s area as a weighting factor. Countries with the highest cRLV were industrialised (NW) European countries such as the Netherlands, Belgium, the Czech Republic and Denmark, whereas large Mediterranean countries such as Spain and Italy had the lowest cRLV. Species for which a Red List assessment was available in at least two European countries and with a relatively high wsRLV (≥ 50) are Colias myrmidone, Pseudochazara orestes, Tomares nogelii, Colias chrysotheme and Coenonympha oedippus. We compared these wsRLVs with the species statuses on the European Red List to identify possible mismatches. We discuss how this complementary method can help to prioritise butterfly conservation on the continental and/or the (sub-)national scale.
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| 3. |
- Van Dyck, Hans, et al.
(författare)
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The lost generation hypothesis : could climate change drive ectotherms into a developmental trap?
- 2015
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Ingår i: Oikos. - : Wiley. - 0030-1299 .- 1600-0706. ; 124:1, s. 54-61
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Tidskriftsartikel (refereegranskat)abstract
- Climate warming affects the rate and timing of the development in ectothermic organisms. Short-living, ectothermic organisms (including many insects) showing thermal plasticity in life-cycle regulation could, for example, increase the number of generations per year under warmer conditions. However, changed phenology may challenge the way organisms in temperate climates deal with the available thermal time window at the end of summer. Although adaptive plasticity is widely assumed in multivoltine organisms, rapid environmental change could distort the quality of information given by environmental cues that organisms use to make developmental decisions. Developmental traps are scenarios in which rapid environmental change triggers organisms to pursue maladaptive developmental pathways. This occurs because organisms must rely upon current environmental cues to predict future environmental conditions and corresponds to a novel case of ecological or evolutionary traps. Examples of introduced, invasive species are congruent with this hypothesis. Based on preliminary experiments, we argue that the dramatic declines of the wall brown Lasiommata megera in northwestern Europe may be an example of a developmental trap. This formerly widespread, bivoltine (or even multivoltine) butterfly has become a conundrum to conservationist biologists. A split-brood field experiment with L. megera indeed suggests issues with life-cycle regulation decisions at the end of summer. In areas where the species went extinct recently, 100% of the individuals developed directly into a third generation without larval diapause, whereas only 42.5% did so in the areas where the species still occurs. Under unfavourable autumn conditions, the attempted third generation will result in high mortality and eventually a lost or suicidal' third generation in this insect with non-overlapping, discrete generations. We discuss the idea of a developmental trap within an integrated framework for assessing the vulnerability of species to climate change.
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| 4. |
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| 5. |
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| 6. |
- van Swaay, Chris A.M., et al.
(författare)
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The European Butterfly Indicator for Grassland species: 1990-2015
- 2016
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report presents the sixth version of the European Grassland Butterfly Indicator, one of the EU biodiversity indicators of the European Environment Agency.The indicator is based on more than 9200 transects in national Butterfly Monitoring Schemes covering 22 countries across Europe, most of them active in the European Union. In 2015, counts were made in more than 4500 transects.Butterflies represent the largest animal group (insects), highly included in food webs, having a high impact on ecosystem services and stability. This report does not represent only the patrimonial conservation of some species, but indicates the changes in biodiversity on grasslands and discusses underlying causes.Fluctuations in numbers between years are typical features of butterfly populations. The assessment of change istherefore made on an analysis of the underlying trend.Indicators were produced on EU, European (EU plus Norway and Switzerland) and pan-European level (including Ukraine, Russia and Armenia).The underlying analysis of the indicator shows that since 1990, grassland butterfly abundance has declined by 30%.The rate of loss has slowed in the last 5-10 years. Part of this slowing down might be caused by climate warming, as this favours cold-blooded animals like butterflies, thus masking the effects of intensification. In parts of Western Europe butterfly numbers outside nature reserves have come to an absolute minimum, meaning it is unlikely for the indicator to further drop.The priority now is to halt further losses and support recovery. This can only come about with greater protection and more sustainable management of semi-natural grassland.
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| 7. |
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| 8. |
- Van Swaay, Cris, et al.
(författare)
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Dos and Don’ts for butterflies of the Habitats Directive of the European Union
- 2012
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Ingår i: Nature Conservation. - : Pensord Press Ltd.. - 1314-6947 .- 1314-3301. ; 1, s. 73-153
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Forskningsöversikt (refereegranskat)abstract
- Twenty-nine butterfly species are listed on the Annexes of the Habitats Directive. To assist everyone who wants or needs to take action for one of these species, we compiled an overview of the habitat requirements and ecology of each species, as well as information on their conservation status in Europe. This was taken from the recent Red List and their main biogeographical regions (taken from the first reporting on Article 17 of the Directive). Most important are the Dos and Don`ts, which summarize in a few bullet points what to do and what to avoid in order to protect and conserve these butterflies and their habitats.
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| 9. |
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| 10. |
- West, Jay B., et al.
(författare)
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Comparison and evaluation of retrospective intermodality image registration techniques
- 1997
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Ingår i: SPIE - The International Society for Optical Engineering. - : SPIE - International Society for Optical Engineering. ; , s. 332-347
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Konferensbidrag (refereegranskat)abstract
- All retrospective image registration methods have attached to them some intrinsic estimate of registration error. However, this estimate of accuracy may not always be a good indicator of the distance between actual and estimated positions of targets within the cranial cavity. This paper describes a project whose principal goal is to use a prospective method based on fiducial markers as a ’gold standard’ to perform an objective, blinded evaluation of the accuracy of several retrospective image-to-image registration techniques. Image volumes of three modalities – CT, MR, and PET – were taken of patients undergoing neurosurgery at Vanderbilt University Medical Center. These volumes had all traces of the fiducial markers removed, and were provided to project collaborators outside Vanderbilt, who then performed retrospective registrations on the volumes, calculating transformations from CT to MR and/or from PET to MR, and communicated their transformations to Vanderbilt where the accuracy of each registration was evaluated. In this evaluation the accuracy is measured at multiple ’regions of interest,’ i.e. areas in the brain which would commonly be areas of neurological interest. A region is defined in the MR image and its centroid C is determined. Then the prospective registration is used to obtain the corresponding point C’ in CT or PET. To this point the retrospective registration is then applied, producing C’ in MR. Statistics are gathered on the target registration error (TRE), which is the disparity between the original point C and its corresponding point C’. A second goal of the project is to evaluate the importance of correcting geometrical distortion in MR images, by comparing the retrospective TRE in the rectified images, i.e., those which have had the distortion correction applied, with that of the same images before rectification. This paper presents preliminary results of this study along with a brief description of each registration technique and an estimate of both preparation and execution time needed to perform the registration.
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