Type of hormonal treatment administered to induce vitellogenesis in European eel influences biochemical composition of eggs and yolk-sac larvae

Egg biochemical composition is among the main factors affecting offspring quality and survival during the yolk-sac stage, when larvae depend exclusively on yolk nutrients. These nutrients are primarily embedded in the developing oocytes during vitellogenesis. In aquaculture, assisted reproduction procedures may be applied enabling gamete production. For the European eel (Anguilla anguilla), reproductive treatment involves administration of pituitary extracts from carp (CPE) or salmon (SPE) to induce and sustain vitellogenesis. In the present study, we compared the influence of CPE and SPE treatments on offspring quality and composition as well as nutrient utilization during the yolk-sac stage. Thus, dry weight, proximal composition (total lipid, total protein), free amino acids, and fatty acids were assessed in eggs and larvae throughout the yolk-sac stage, where body and oil-droplet area were measured to estimate growth rate, oil-droplet utilization, and oil-droplet utilization efficiency. The results showed that CPE females spawned eggs with higher lipid and free amino acid contents. However, SPE females produced more buoyant eggs with higher fertilization rate as well as larger larvae with more energy reserves (estimated as oil-droplet area). Overall, general patterns of nutrient utilization were detected, such as the amount of total lipid and monounsaturated fatty acids decreasing from the egg stage and throughout the yolk-sac larval stage. On the contrary, essential fatty acids and free amino acids were retained. Notably, towards the end of the yolk-sac stage, the proximal composition and biometry of surviving larvae, from both treatments, were similar

Assessment of lipid uptake and fatty acid metabolism of European eel larvae (Anguilla anguilla) determined by 14C in vivo incubation

Knowledge on dietary nutrient requirements of first-feeding European eel larvae (Anguilla anguilla) is very limited. This study provides first ever information on in vivo lipid uptake and fatty acid (FA) metabolism of European pre-leptocephalus eel larvae and advances directions for dietary lipid and FA inclusions. The in vivo capability of eel larvae to incorporate and metabolize unsaturated fatty acids was tested on larvae at different ontogenetic stages (4, 8 and 12 days post hatch, DPH). Larvae were incubated in 10 mL flat-bottom tissue culture plates, with [1-14C]-labelled FA (18:2n-6, ALA; 18:3n-3, LA; 20:4n-6, ARA and 20:5n-3, EPA) directly added to seawater. The capability of the larvae for de-acylation and re-acylation of [1-14C]arachidonic acid (ARA), initially bound to phosphatidylcholine (PC) and phosphatidylethanolamine (PE), was also investigated. In all cases, control incubations without any radiolabelled substrate were performed for further lipid analysis. The results revealed that direct incubation with 14C-labelled FA is a feasible method to investigate in vivo FA and phospholipids metabolism of pre-leptocephalus stages of the European eel. No enzymatic elongation/desaturation activity towards [1-14C]C18 or [1-14C]C20 FA was detected. Consequently, ARA, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) must be considered essential FA and thus provided firstly through female broodstock and later through diet at least during the first-feeding stage. Pre-leptocephalus larvae display a high capacity to remodel dietary phospholipids with a preferential esterification of all FA substrates into PC. The unexpectedly high esterification rate of [1-14C] ARA into PC and PE is supported by the individual FA profiles of the larval phospholipids. The high levels of ARA present in the European eel larvae denotes its physiological relevance for this species. It is therefore essential to consider this FA as particularly important when designing suitable broodstock – or first-feeding diets for this species

Sampling of temporal networks: methods and biases

Temporal networks have been increasingly used to model a diversity of systems that evolve in time; for example, human contact structures over which dynamic processes such as epidemics take place. A fundamental aspect of real-life networks is that they are sampled within temporal and spatial frames. Furthermore, one might wish to subsample networks to reduce their size for better visualization or to perform computationally intensive simulations. The sampling method may affect the network structure and thus caution is necessary to generalize results based on samples. In this paper, we study four sampling strategies applied to a variety of real-life temporal networks. We quantify the biases generated by each sampling strategy on a number of relevant statistics such as link activity, temporal paths and epidemic spread. We find that some biases are common in a variety of networks and statistics, but one strategy, uniform sampling of nodes, shows improved performance in most scenarios. Given the particularities of temporal network data and the variety of network structures, we recommend that the choice of sampling methods be problem oriented to minimize the potential biases for the specific research questions on hand. Our results help researchers to better design network data collection protocols and to understand the limitations of sampled temporal network data

VerdictDB: Universalizing Approximate Query Processing

Despite 25 years of research in academia, approximate query processing (AQP) has had little industrial adoption. One of the major causes of this slow adoption is the reluctance of traditional vendors to make radical changes to their legacy codebases, and the preoccupation of newer vendors (e.g., SQL-on-Hadoop products) with implementing standard features. Additionally, the few AQP engines that are available are each tied to a specific platform and require users to completely abandon their existing databases---an unrealistic expectation given the infancy of the AQP technology. Therefore, we argue that a universal solution is needed: a database-agnostic approximation engine that will widen the reach of this emerging technology across various platforms. Our proposal, called VerdictDB, uses a middleware architecture that requires no changes to the backend database, and thus, can work with all off-the-shelf engines. Operating at the driver-level, VerdictDB intercepts analytical queries issued to the database and rewrites them into another query that, if executed by any standard relational engine, will yield sufficient information for computing an approximate answer. VerdictDB uses the returned result set to compute an approximate answer and error estimates, which are then passed on to the user or application. However, lack of access to the query execution layer introduces significant challenges in terms of generality, correctness, and efficiency. This paper shows how VerdictDB overcomes these challenges and delivers up to 171$\times$ speedup (18.45$\times$ on average) for a variety of existing engines, such as Impala, Spark SQL, and Amazon Redshift, while incurring less than 2.6% relative error. VerdictDB is open-sourced under Apache License.Comment: Extended technical report of the paper that appeared in Proceedings of the 2018 International Conference on Management of Data, pp. 1461-1476. ACM, 201

Energy Scenarios for South Eastern Europe: A close look into the Western Balkans

"The Energy Scenarios for South East Europe" thematic seminar took place on the 15th of December 2015 in Vienna, Austria. The workshop was organized by Institute of Energy and Transport of the European Commission's Joint Research Centre (JRC-IET), hosted by the Energy Community Secretariat (ECS) and sponsored by the Directorate-General for Neighbourhood and Enlargement Negotiations (DG-NEAR) in the framework of the Travel Accommodation and Conference facility for Western Balkans and Turkey, a programme of dissemination activities organised by the Commission in the EU or the beneficiary country in connection with the enlargement process and the pre-accession strategy. The aim of the workshop was to bring together representatives from think tanks, scientific institutes, the academia and the private sector with government officials, the national statistical agencies and the local TSO representatives from the Western Balkan region to exchange views on potential energy technology deployment scenarios that could facilitate a low carbon development pathway for the enlargement countries, but also exchange on the methodologies utilized and identify challenges as well as potential pitfalls in this process. The workshop included three sessions of specific thematic focus. The first session provided the "regional picture" with forecasts on the development of the energy and power systems in the western Balkans. The second session discussed case studies on low carbon development trajectories for specific countries in the region; and the third session explored the role of particular technologies in this context. This report comprises of long abstracts from the workshop presentations and closes with a chapter on conclusions and recommendations that resulted from the discussion sessions

Prox1 Regulates the Notch1-Mediated Inhibition of Neurogenesis

During development of the spinal cord, Prox1 controls the balance between proliferation and differentiation of neural progenitor cells via suppression of Notch1 gene expression

Synthesis of accelerograms compatible with the Chinese GB 50011-2001 design spectrum via harmonic wavelets: artificial and historic records

A versatile approach is employed to generate artificial accelerograms which satisfy the compatibility criteria prescribed by the Chinese aseismic code provisions GB 50011-2001. In particular, a frequency dependent peak factor derived by means of appropriate Monte Carlo analyses is introduced to relate the GB 50011-2001 design spectrum to a parametrically defined evolutionary power spectrum (EPS). Special attention is given to the definition of the frequency content of the EPS in order to accommodate the mathematical form of the aforementioned design spectrum. Further, a one-to-one relationship is established between the parameter controlling the time-varying intensity of the EPS and the effective strong ground motion duration. Subsequently, an efficient auto-regressive moving-average (ARMA) filtering technique is utilized to generate ensembles of non-stationary artificial accelerograms whose average response spectrum is in a close agreement with the considered design spectrum. Furthermore, a harmonic wavelet based iterative scheme is adopted to modify these artificial signals so that a close matching of the signals’ response spectra with the GB 50011-2001 design spectrum is achieved on an individual basis. This is also done for field recorded accelerograms pertaining to the May, 2008 Wenchuan seismic event. In the process, zero-phase high-pass filtering is performed to accomplish proper baseline correction of the acquired spectrum compatible artificial and field accelerograms. Numerical results are given in a tabulated format to expedite their use in practice