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154.
Heroen Verbruggen Lennert Tyberghein Gareth S. Belton Frederic Mineur Alexander Jueterbock Galice Hoarau C. Frederico D. Gurgel Olivier De Clerck 《PloS one》2013,8(6)
The utility of species distribution models for applications in invasion and global change biology is critically dependent on their transferability between regions or points in time, respectively. We introduce two methods that aim to improve the transferability of presence-only models: density-based occurrence thinning and performance-based predictor selection. We evaluate the effect of these methods along with the impact of the choice of model complexity and geographic background on the transferability of a species distribution model between geographic regions. Our multifactorial experiment focuses on the notorious invasive seaweed
Caulerpacylindracea
(previously
Caulerpa
racemosa
var.
cylindracea
) and uses Maxent, a commonly used presence-only modeling technique. We show that model transferability is markedly improved by appropriate predictor selection, with occurrence thinning, model complexity and background choice having relatively minor effects. The data shows that, if available, occurrence records from the native and invaded regions should be combined as this leads to models with high predictive power while reducing the sensitivity to choices made in the modeling process. The inferred distribution model of
Caulerpacylindracea
shows the potential for this species to further spread along the coasts of Western Europe, western Africa and the south coast of Australia. 相似文献
155.
Prinsen K Jin L Vunckx K De Saint-Hubert M Zhou L Cleynhens J Nuyts J Bormans G Ni Y Verbruggen A 《Bioorganic & medicinal chemistry letters》2011,21(1):502-505
N,N'-bis(diethylenetriamine pentaacetic acid)-3,3'-(benzylidene)-bis-(1H-indole-2-carbohydrazide) (bis-DTPA-BI) was radiolabeled with (99m)Tc(CO)(3). The resulting (99m)Tc(CO)(3)-bis-DTPA-BI was characterized (LC-MS) and evaluated as a potential SPECT tracer for imaging of necrosis in Wistar rats with a reperfused partial liver infarction and Wistar rats with ethanol induced muscular necrosis. To study the specificity, uptake of (99m)Tc(CO)(3)-bis-DTPA-BI was also studied in a mouse model of Fas-mediated hepatic apoptosis. The obtained results indicate that (99m)Tc(CO)(3)-bis-DTPA-BI displays selective uptake in necrotic tissue and can be used for in vivo visualization of necrosis by SPECT. 相似文献
156.
Souffreau C Verbruggen H Wolfe AP Vanormelingen P Siver PA Cox EJ Mann DG Van de Vijver B Sabbe K Vyverman W 《Molecular phylogenetics and evolution》2011,61(3):866-879
Pinnularia is an ecologically important and species-rich genus of freshwater diatoms (Bacillariophyceae) showing considerable variation in frustule morphology. Interspecific evolutionary relationships were inferred for 36 Pinnularia taxa using a five-locus dataset. A range of fossil taxa, including newly discovered Middle Eocene forms of Pinnularia, was used to calibrate a relaxed molecular clock analysis and investigate temporal aspects of the genus' diversification. The multi-gene approach resulted in a well-resolved phylogeny of three major clades and several subclades that were frequently, but not universally, delimited by valve morphology. The genus Caloneis was not recovered as monophyletic, confirming that, as currently delimited, this genus is not evolutionarily meaningful and should be merged with Pinnularia. The Pinnularia-Caloneis complex is estimated to have diverged between the Upper Cretaceous and the early Eocene, implying a ghost range of at least 10 million year (Ma) in the fossil record. 相似文献
157.
Johanna A. A. Bos Frederike Verbruggen Stefan Engels Philippe Cromb�� 《Vegetation History and Archaeobotany》2013,22(1):17-38
Late-glacial vegetation changes were studied at Rieme, NW Belgium. Human occupation of this cover sand area occurred from the Final Palaeolithic onwards. The research area is situated on the northern side of a large cover sand ridge in an undulating landscape with small ridges and depressions. The past landscape was reconstructed using a multi-disciplinary approach, including geomorphological, sedimentological, loss-on-ignition, botanical (micro- and macrofossil) and zoological analyses. AMS 14C dating provided an accurate chronology for the sediments. Analyses were performed on three sequences located ~200?C300?m apart. Our study shows that during the B?lling (GI-1e) wet meadows developed on the sandy soils and groundwater levels increased probably as result of permafrost melting. Shallow pools formed in depressions. During the Older Dryas (GI-1d) shrubs with juniper, sea-buckthorn and willow developed. Many shallow depressions were overblown with sand and deposition of organic material almost ceased. In the early Aller?d (GI-1c) open birch woodlands developed. Due to the final melting of permafrost, groundwater levels rose further and ponds with floating-leaved open water vegetation developed. Large water level fluctuations occurred in one of the ponds. Accumulation of organic deposits ceased during the mid-Aller?d. Indirect evidence for human occupation during the Aller?d (GI-1c) was found in indications of burning of the reed-swamps in combination with the presence of large herbivores. Final Palaeolithic people probably used the northern side of the cover sand ridge as hunting area, while they settled their temporary (base) camps on the steep southern side along the extensive and deeper Moervaart lake. 相似文献
158.
Codium recurvatum is described from material collected on a Tanzanian reef slope. The diminutive species is easily recognized by its unusual morphology, as its thallus consists of several dorsiventrally flattened lobes originating from a central holdfast and curving back towards the substratum. DNA barcodes (rbcL exon 1 and tufA) confirm the distinctness of the species and the phylogenetic placement of the new species is inferred from a concatenated alignment of rbcL and rps3–rpl16 sequences. 相似文献
159.
160.
Vander Cruyssen B Van Looy S Wyns B Westhovens R Durez P Van den Bosch F Veys EM Mielants H De Clerck L Peretz A Malaise M Verbruggen L Vastesaeger N Geldhof A Boullart L De Keyser F 《Arthritis research & therapy》2005,7(5):R1063-R1071
This study is based on an expanded access program in which 511 patients suffering from active refractory rheumatoid arthritis (RA) were treated with intravenous infusions of infliximab (3 mg/kg+methotrexate (MTX)) at weeks 0, 2, 6 and every 8 weeks thereafter. At week 22, 474 patients were still in follow-up, of whom 102 (21.5%), who were not optimally responding to treatment, received a dose increase from week 30 onward. We aimed to build a model to discriminate the decision to give a dose increase. This decision was based on the treating rheumatologist's clinical judgment and therefore can be considered as a clinical measure of insufficient response. Different single and composite measures at weeks 0, 6, 14 and 22, and their differences over time were taken into account for the model building. Ranking of the continuous variables based on areas under the curve of receiver-operating characteristic (ROC) curve analysis, displayed the momentary DAS28 (Disease Activity Score including a 28-joint count) as the most important discriminating variable. Subsequently, we proved that the response scores and the changes over time were less important than the momentary evaluations to discriminate the physician's decision. The final model we thus obtained was a model with only slightly better discriminative characteristics than the DAS28. Finally, we fitted a discriminant function using the single variables of the DAS28. This displayed similar scores and coefficients as the DAS28. In conclusion, we evaluated different variables and models to discriminate the treating rheumatologist's decision to increase the dose of infliximab (+MTX), which indicates an insufficient response to infliximab at 3 mg/kg in patients with RA. We proved that the momentary DAS28 score correlates best with this decision and demonstrated the robustness of the score and the coefficients of the DAS28 in a cohort of RA patients under infliximab therapy. 相似文献