Gonçalo M. Marques

Stylized facts in microalgal growth: interpretation in a dynamic energy budget context

A dynamic energy budget (DEB) model for microalgae is proposed. This model deviates from the standard DEB model as it needs more reserves to cope with the variation of assimilation pathways, requiring a different approach to growth based on the synthesizing unit (SU) theory for multiple substrates. It is shown that the model is able to accurately predict experimental data in constant and light-varying conditions with most of the parameter values taken directly from the literature. Also, model simulations are shown to be consistent with stylized facts (SFs) concerning N∶C ratio. These SFs are reinterpreted and the general conclusion is that all forcing variables (dilution rate, temperature and irradiance) impose changes in the nitrogen or carbon limitation status of the population, and consequently on reserve densities. Model predictions are also evaluated in comparison with SFs on chlorophyll concentration. It is proposed that an extra structure, more dependent on the nitrogen reserve, is required to accurately model chlorophyll dynamics. Finally, SFs concerning extracellular polymeric substances (EPSs) production by benthic diatoms are collected and interpreted and a formulation based on product synthesis and rejection flux is proposed for the EPSs production rate.

A dynamic energy budget for the whole life-cycle of holometabolous insects

Alterations of the amount and quality of food consumed during ontogeny can affect different life-history traits, such as growth rate, developmental time, survival, adult size, and fitness. Understanding the dynamics of such metabolic and energetic pathways and investments is particularly challenging in the case of holometabolous insects due to their strikingly different life stages. We show how whole life-cycle energy and mass budgets can be achieved for holometabolic insects through dynamic energy budget (DEB) theory, permitting the fate of acquired and stored nutrients to be followed over a complete life-cycle. We applied the DEB theory to model the whole life-cycle energetics of an endoparasitic wasp, Venturia canescens (Hymenoptera: Ichneumonidae). Data on embryo, larval, and pupal dry mass, imago longevity, and fecundity were used for assessing the goodness of fit of the model. Our model predicted the growth curves of the larval and pupal stages, the number of eggs laid by the imago through time, and lifespan events, such as the different developmental times of the parasitoid. The model enabled us to distinguish and follow the energy invested in eggs through income and capital reserves. The mechanisms leading to the double costs of being small (a shorter life under starving conditions and fewer eggs) were identified by running the model for varying amounts of food eaten early in life, according to host sizes. The final larval instar harvests around 60 times the energy of a recently hatched larva. Around 90% of this energy is then used during pupation to build the structure of the imago and to pay maintenance. Imagoes, therefore, emerge with only a small percentage of the energy stored by the last instar larvae. Our study shows that, despite being small, this percentage of energy stored during the parasitoid development has a great impact on adult fitness, the loss of which cannot be compensated for by a rich adult environment. Our model is generic and has applications for a wide range of applied and theoretical questions about insect energetics, from population dynamics in multitrophic systems to responses to climate change and life-history strategies.

The AmP project: Comparing species on the basis of dynamic energy budget parameters

We developed new methods for parameter estimation-in-context and, with the help of 125 authors, built the AmP (Add-my-Pet) database of Dynamic Energy Budget (DEB) models, parameters and referenced underlying data for animals, where each species constitutes one database entry. The combination of DEB parameters covers all aspects of energetics throughout the full organism’s life cycle, from the start of embryo development to death by aging. The species-specific parameter values capture biodiversity and can now, for the first time, be compared between animals species. An important insight brought by the AmP project is the classification of animal energetics according to a family of related DEB models that is structured on the basis of the mode of metabolic acceleration, which links up with the development of larval stages. We discuss the evolution of metabolism in this context, among animals in general, and ray-finned fish, mollusks and crustaceans in particular. New DEBtool code for estimating DEB parameters from data has been written. AmPtool code for analyzing patterns in parameter values has also been created. A new web-interface supports multiple ways to visualize data, parameters, and implied properties from the entire collection as well as on an entry by entry basis. The DEB models proved to fit data well, the median relative error is only 0.07, for the 1035 animal species at 2018/03/12, including some extinct ones, from all large phyla and all chordate orders, spanning a range of body masses of 16 orders of magnitude. This study is a first step to include evolutionary aspects into parameter estimation, allowing to infer properties of species for which very little is known.

Microscopic derivation of pion–nucleon and pion–delta scattering lengths

Abstract A general expression for the π – N and π – Δ scattering lengths is derived in the framework of a microscopic calculation. Annihilation, negative energy wave functions and spontaneous chiral symmetry are included consistently. The point-like limit is used to calculate the scattering lengths.

Comment on “Energy Uptake and Allocation During Ontogeny”

Hou et al. (Reports, 31 October 2008, p. 736) presented a model for energy uptake and allocation over an organism’s growth and development. However, their model does not account for allocation to reproduction (essential to adults) and growth without assimilation (essential to embryos) and is therefore only applicable to organisms growing with abundant food in the juvenile stage.

Dynamic energy budget models in ecological risk assessment: From principles to applications

In ecological risk assessment of chemicals, hazard identification and hazard characterisation are most often based on ecotoxicological tests and expressed as summary statistics such as No Observed Effect Concentrations or Lethal Concentration values and No Effect Concentrations. Considerable research is currently ongoing to further improve methodologies to take into account toxico kinetic aspects in toxicological assessments, extrapolations of toxic effects observed on individuals to population effects and combined effects of multiple chemicals effects. In this context, the principles of the Dynamic Energy Budget (DEB), namely the conserved allocation of energy to different life-supporting processes in a wide variety of different species, have been applied successfully to the development of a number of DEB models. DEB models allow the incorporation of effects on growth, reproduction and survival within one consistent framework. This review aims to discuss the principles of the DEB theory together with available DEB models, databases available and applications in ecological risk assessment of chemicals for a wide range of species and taxa. Future perspectives are also discussed with particular emphasis on ongoing research efforts to develop DEB models as open source tools to further support the research and regulatory community to integrate quantitative biology in ecotoxicological risk assessment.

Hard core attraction in hadron scattering and the family of the Ds meson molecule

We study the discovered Ds(2317) at BABAR, CLEO and BELLE, and find that it belongs to a class of strange multiquarks, which is equivalent to the class of kaonic molecules bound by hard core attraction. In this class of hadrons a kaon is trapped by a s‐wave meson or baryon. To describe this class of multiquarks we apply the Resonating Group Method, and extract the hard core kaon‐meson(baryon)interactions. We derive a criterion to classify the attractive channels. We find that the mesons f0(980), Ds(2457), Bs scalar and axial, and also the baryons with the quantum numbers of Λ, Ⅺc, Ⅺb and also Ωcc, Ωcb and Ωbb belong to the new hadronic class of the Ds(2317).

DEBSe@: an e-learning platform to introduce the Dynamic Energy Budget (DEB) theory for marine ecology, fisheries sciences and aquaculture applications

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. DEBSe@: an e-learning platform to introduce the Dynamic Energy Budget (DEB) theory for marine ecology, fisheries sciences and aquaculture applications Yoann Thomas, Fred Jean, Laure Pecquerie, Gonçalo Marques, Sébastien Hervé, Valérie Dantec, Jonathan Flye-Sainte-Marie

Schwinger-Dyson equations and the quark-antiquark static potential

CFC, Departamento de F’isica, Universidade de Coimbra,In lattice QCD, a confining potential for a static quark-antiquark pair can be computed with theWilson loop technique. This potential, dominated by a linear potential at moderate distances,is consistent with the confinement with a flux tube, an extended and scalar system also directlyobservable in lattice QCD. Quantized flux tubes have also been observed in another class of con-finement, the magnetic confinement in type II superconductors. On the other hand the solutionof Schwinger Dyson Equations, say with the Landau gauge fixing and the truncation of the seriesof Feynman diagrams, already at the rainbow level for the self energy and at the ladder level forthe Bethe Salpeter equation, provides a signal of a possible inverse quartic potential in momen-tum space derived from one gluon and one ghost exchange, consistent with confinement. Herewe address the successes, difficulties and open problems of the matching of these two differentperspectives of confinement, the Schwinger-Dyson perspective versus the flux tube perspective.International Workshop on QCD GreenSs Functions, Confinement and PhenomenologySeptember 7-11 , 2009ECT Trento, Italy

Life engine - creating artificial life for scientific and entertainment purposes

The Dynamic Energy Budget (DEB) theory has become a fundamental tool in modeling the metabolic behaviour of organisms. Its capacity to describe the biological aspect of life alone justifies its applicability in Artificial Life. Aware of this potential, the DEB research group in Instituto Superior Tecnico (IST) in Lisbon has joined the videogame company Biodroid Entertainment in the Life Engine project. This project aims to develop a library for scientific purposes but also to create a biology engine for videogames. From the scientific point-of-view, this library is intended to be the standard tool for DEB researchers and, at the same time, to popularize DEB theory in other scientific communities, such as the AL community.