Blocking representation in the ERA-Interim driven EURO-CORDEX RCMs

While Regional Climate Models (RCMs) have been shown to yield improved simulations compared to General Circulation Model (GCM), their representation of large-scale phenomena like atmospheric blocking has been hardly addressed. Here, we evaluate the ability of RCMs to simulate blocking situations present in their reanalysis driving data and analyse the associated impacts on anomalies and biases of European 2-m air temperature (TAS) and precipitation rate (PR). Five RCM runs stem from the EURO-CORDEX ensemble while three RCMs are WRF models with different nudging realizations, all of them driven by ERA-Interim for the period 1981?2010. The detected blocking systems are allocated to three sectors of the Euro-Atlantic region, allowing for a characterization of distinctive blocking-related TAS and PR anomalies. Our results indicate some misrepresentation of atmospheric blocking over the EURO-CORDEX domain, as compared to the driving reanalysis. Most of the RCMs showed fewer blocks than the driving data, while the blocking misdetection was negligible for RCMs strongly conditioned to the driving data. A higher resolution of the RCMs did not improve the representation of atmospheric blocking. However, all RCMs are able to reproduce the basic anomaly structure of TAS and PR connected to blocking. Moreover, the associated anomalies do not change substantially after correcting for the misrepresentation of blocking in RCMs. The overall model bias is mainly determined by pattern biases in the representations of surface parameters during non-blocking situations. Biases in blocking detections tend to have a secondary influence in the overall bias due to compensatory effects of missed blockings and non-blockings. However, they can lead to measurable effects in the presence of a strong blocking underestimation.This work was funded by the Austrian Science Fund (FWF) under the project: Understanding Contrasts in high Mountain hydrology in Asia (UNCOMUN: I 1295-N29). This research was supported by the Faculty of Environmental, Regional and Educational Sciences (URBI), University of Graz, as well as the Federal Ministry of Science, Research and Economy (BMWFW) by funding the OeAD Grant Marietta Blau. This work was partially supported (JMG and SH) by the project MULTI-SDM (CGL2015-66583- R, MINECO/FEDER). DB was supported by the PALEOSTRAT (CGL2015-69699-R) project funded by the Spanish Ministry of Economy and Competitiveness (MINECO)

Effect of early co-feeding and different weaning diets on the performance of cobia (Rachycentron canadum) larvae and juveniles

Cobia (Rachycentron canadum) is a very fast growing species. This can only be achieved if sufficient amounts of feed are provided from early larval development onwards. In this study, we examined the effects of early co-feeding and different co-feeding formulated diets on growth, survival and vitality of cobia larvae and juveniles. Two experiments were conducted to test the possibility of early co-feeding of the two formulated diets for cobia larvae (8–18 dph) and one experiment was conducted to compare the effect of three formulated diets for cobia juveniles (20–38 dph). During the larval stage, two formulated diets: Proton® and an experimental diet (INVE, Belgium) were used along with live food from eight days post hatch (dph) and 13 dph compared to 18 dph as the control. Results from the study indicated that early co-feeding of Proton® from eight dph had a significantly positive effect on growth (P 0.05), but not on survival and stress resistance in a salinity stress test (P > 0.05) of cobia larvae. In the second trial, no significant difference (P > 0.05) was detected between all treatments in terms of growth, vitality and survival. However, high mortality occurred in the treatment with the experimental diet as of 12 dph. The study suggested that early co-feeding of Proton® to cobia larvae from eight dph is possible and research on the appropriate nutritional composition of weaning diets needs to be addressed. In the juvenile stage, three formulated diets, i.e. the experimental diet, Proton® and NRD® (INVE Aquaculture NV) were evaluated for growth performance and survival of early cobia juveniles (20–38 dph). The diets were manually introduced from 22 dph at a feeding frequency of every 2 h until satiation, while feeding of enriched EG Artemia was maintained until 30 dph. Average length and weight of the 38-dph juveniles fed the experimental diet were significantly higher (P 0.05) compared to larvae fed Proton® and NRD®. However, the coefficient of size variation as well as the cumulative stress index in a salinity challenge test was not significantly different (P > 0.05). Survival in the Proton® treatment was the lowest, while no significant difference was evident between the experimental diet and NRD® treatments. The mortality rate of all three treatments had two peaks: one at the beginning of the experiment and one when live food feeding was discontinued. This result indicates that the nutritional requirements of cobia are age-dependent and prolongation of live food co-feeding during weaning may be necessary. The higher DHA/EPA ratio in the experimental diet can be a clue for the improvement of growth and survival of cobia during the weaning stage

A phenotypic screen in zebrafish identifies a novel small-molecule inducer of ectopic tail formation suggestive of alterations in non-canonical Wnt/PCP signaling

Zebrafish have recently emerged as an attractive model for the in vivo bioassay-guided isolation and characterization of pharmacologically active small molecules of natural origin. We carried out a zebrafish-based phenotypic screen of over 3000 plant-derived secondary metabolite extracts with the goal of identifying novel small-molecule modulators of the BMP and Wnt signaling pathways. One of the bioactive plant extracts identified in this screen - Jasminum gilgianum, an Oleaceae species native to Papua New Guinea - induced ectopic tails during zebrafish embryonic development. As ectopic tail formation occurs when BMP or non-canonical Wnt signaling is inhibited during the tail protrusion process, we suspected a constituent of this extract to act as a modulator of these pathways. A bioassay-guided isolation was carried out on the basis of this zebrafish phenotype, identifying para-coumaric acid methyl ester (pCAME) as the active compound. We then performed an in-depth phenotypic analysis of pCAME-treated zebrafish embryos, including a tissue-specific marker analysis of the secondary tails. We found pCAME to synergize with the BMP-inhibitors dorsomorphin and LDN-193189 in inducing ectopic tails, and causing convergence-extension defects in compound-treated embryos. These results indicate that pCAME may interfere with non-canonical Wnt signaling. Inhibition of Jnk, a downstream target of Wnt/PCP signaling (via morpholino antisense knockdown and pharmacological inhibition with the kinase inhibitor SP600125) phenocopied pCAME-treated embryos. However, immunoblotting experiments revealed pCAME to not directly inhibit Jnk-mediated phosphorylation of c-Jun, suggesting additional targets of SP600125, and/or other pathways, as possibly being involved in the ectopic tail formation activity of pCAME. Further investigation of pCAME's mechanism of action will help determine this compound's pharmacological utility