On fitting planetary systems in counter-revolving configurations

In Gayon & Bois (2008) and Gayon etal (2009), (i) we studied the theoretical feasibility and efficiency of retrograde mean motion resonances (i.e. two planets are both in orbital resonance and in counter-revolving configuration), (ii) we showed that retrograde resonances can generate interesting mechanisms of stability, and (iii) we obtained a dynamical fit involving a counter-revolving configuration that is consistent with the observations of the HD73526 planetary system. In the present paper, we present and analyze data reductions assuming counter-revolving configurations for eight compact multi-planetary systems detected through the radial velocity method. In each case, we select the best fit leading to a dynamically stable solution. The resulting data reductions obtained in rms and chi values for counter-revolving configurations are of the same order, and sometimes slightly better, than for prograde configurations. In the end, these fits tend to show that, over the eight studied multi-planetary systems, six of them could be regulated by a mechanism involving a counter-revolving configuration.Comment: 4 pages, 1 figure, 2 tables, accepted for publication in MNRAS letters (August 10, 2009

Economic Natural Selection: What Concept of Selection?

International audienceThe article examines two cases of adoption of evolutionary ways of thinking by modern economists: Nelson and Winter's (Evolutionary Theory of Economic Change, 1982), and evolutionary game theory (1990s and after). In both cases, the authors explicitly refer to natural selection in an economic context. I show that natural selection is taken in two different senses, which correspond to two general conceptions of the principle of natural selection, one of which contains reproduction and heredity as key elements, whereas the other does not

Évolution et hasard

Dans la théorie contemporaine de l’évolution, trois sens classiques de la notion de hasard interviennent : la notion ordinaire de chance, la notion probabiliste de l’aléatoire, et la notion épistémologique de contingence relativement à un système théorique. Ces trois notions suffisent à définir le statut du hasard aux principaux niveaux du processus évolutif où l’on invoque communément des effets fortuits : mutations, dérive génétique, révolutions génétiques, changements écologiques, macroévolution. On se demande enfin si les divers sens du hasard rencontrés dans cette étude peuvent être ramenés à l’unité, et s’ils renvoient à un hasard subjectif (ou « épistémique ») ou à un hasard objectif.In the contemporary theory of evolution, three classical meanings of the notion of chance come into play : the ordinary meaning of chance, the probabilistic notion of randomness, and the epistemological notion of contingency with reference to a theoretical system. These three notions are sufficient in order to define the status of chance on the principal levels of the evolutive process where fortuitous effects are commonly invoked : mutations, genetic deviations, genetic revolutions, ecological changes, macroevolution. The question is raised, finally, whether the diverse meanings of chance considered in the present study may be brought to one, and whether they refer to a subjective (or “epistemic”) form of chance or to an objective chance

From Mendel to epigenetics: History of genetics

AbstractThe origins of genetics are to be found in Gregor Mendel's memoir on plant hybridization (1865). However, the word ‘genetics’ was only coined in 1906, to designate the new science of heredity. Founded upon the Mendelian method for analyzing the products of crosses, this science is distinguished by its explicit purpose of being a general ‘science of heredity’, and by the introduction of totally new biological concepts (in particular those of gene, genotype, and phenotype). In the 1910s, Mendelian genetics fused with the chromosomal theory of inheritance, giving rise to what is still called ‘classical genetics’. Within this framework, the gene is simultaneously a unit of function and transmission, a unit of recombination, and of mutation. Until the early 1950s, these concepts of the gene coincided. But when DNA was found to be the material basis of inheritance, this congruence dissolved. Then began the venture of molecular biology, which has never stopped revealing the complexity of the way in which hereditary material functions

Enzymatic cybernetics: An unpublished work by Jacques Monod

International audienceIn 1959, Jacques Monod wrote a manuscript entitled Cybernétique enzymatique [Enzymatic cybernetics]. Never published, this unpublished manuscript presents a synthesis of how Monod interpreted enzymatic adaptation just before the publication of the famous papers of the 1960s on the operon. In addition, Monod offers an example of a philosophy of biology immersed in scientific investigation. Monod's philosophical thoughts are classified into two categories, methodological and ontological. On the methodological side, Monod explicitly hints at his preferences regarding the scientific method in general: hypothetical-deductive method, and use of theoretical models. He also makes heuristic proposals regarding molecular biology: the need to analyse the phenomena in question at the level of individual cells, and the dual aspect of all biological explanation, functional and evolutionary. Ontological issues deal with the notions of information and genetic determinism, “cellular memory”, the irrelevance of the notion of “living matter”, and the usefulness of a cybernetic comprehension of molecular biology

Value Chain Analysis of Calamansi in Cagayan Valley, Northern Philippines

Calamansi (×Citrofortunella microcarpa) is an economically important citrus cultivar produced in Cagayan Valley. Its demand is high because it is used in various condiments, beverages, dishes, marinades, preserves, beauty products, and medicines. However, data shows that the production of and hectarage planted to calamansi in the Cagayan Valley is decreasing. Thus, this study was conducted to analyze the calamansi value chain and suggest areas for intervention. Following the methodology published by the Philippine Council for Agriculture, Aquatic and Natural Resources Research and Development (PCAARRD), data were gathered to answer six key questions: key customers and product requirements; product, information, and payment flow; activities and services along the chain; key players and their roles; critical logistic issues and concerns; and external influences. The key customers for calamansi are the processors. But despite the number of processors who could buy volumes of calamansi, farm-gate price would range from PhP 2 per kg during the peak months of production to PhP 65 per kg during the lean months. The price is normally dictated by consolidators who sell the calamansi to processors. Generally, processors buy from consolidators and not directly from farmers. The main reasons for this practice is that individual farmers could not supply the needed volume and quality of calamansi required by processors; thus, farmers are at the mercy of consolidators. Recommendations for intervention are the following: accredited sources of seedlings for quality produce, increase technical support, linking of farmers to markets, and organizing farmers into association or cooperatives for them to process their own produce and to be able to avail of government support from production to processing

Supply Chain Improvement of Soybean in Northern Philippines

Soybean (Glycine max [L.] Merr.) is a high-protein legume used as animal feed and as an industrial raw material. It is also processed into food products such as soymilk, roasted soya (soy coffee), soy powder, tokwa (tofu) or soybean curd, taho, soy sauce, and bread. In some areas, soybean is being consumed as vegetable (sprouts). Despite its various uses, soybean production in the Philippines is limited. Hence, this study was conducted to assess the supply chain of soybeans in Northern Philippines (Regions 2 and 3) and identify areas for improvement. Following the ACIAR-PCAARRD methodology in conducting a supply chain study, primary data were collected to answer the six key questions: key customers and product requirements; product, information, and payment flow; activities and services along the chain; key players and their roles; critical logistic issues and concerns; and what are the external influences. Soybean processors were identified as the key customers with volume requirements reaching around 100 tons per year. Results show that farmers lack technical knowledge in the production and marketing of soybeans and complained about the lack of market for their produce. On the other hand, processors explained they resort to using imported soybeans because of the low quality or lack of locally produced soybeans. It is therefore recommended that farmers be organized into associations or cooperatives to better avail of government support, from input provision to marketing and processing of soybeans. For farmers who cannot process their soybeans, they should be linked to processors

Machine learning and simulation for the optimisation and characterisation of electrodes in batterie

The performance of electrochemical energy storage (EES) and energy conversion (EC) technologies is closely related to their electrode microstrcuture. Thus, this work focuses on the development of two novel computational models for the characterisation and optimisation of electrodes for three devices: Redox Flow batteries (RFBs), Solid Oxide Fuel Cells (SOFCs), and Lithium-ion batteries (LIBs). The first method introduces a Pore Network Model (PNM) for simulating the coupled charge and mass transport processes within electrodes. This approach is implemented for a vanadium RFB using different commercially available carbon-based electrodes. The results from the PNM show non-uniformity in the concentration and current density distributions within the electrode, which leads to a fast discharge due to regions where mass-transport limitations are predominant. The second approach is based on the stochastic reconstruction of synthetic electrode microstructures. For this purpose, a deep convolutional generative adversarial network (DC-GAN) is implemented for generating three-dimensional n-phase microstructures of a LIB cathode and a SOFC anode. The results show that the generated data is able to represent the morphological properties and two-point correlation function of the real dataset. As a subsequent process, a generation-optimisation closed-loop algorithm is developed using Gaussian Process Regression and Bayesian optimisation for the design of microstructures with customised properties. The results show the ability to perform simultaneous maximisation of correlated properties (specific surface area and relative diffusivity), as well as an optimisation of these properties constrained by constant values of volume fraction. Overall, this work presents a comprehensive analysis of the effect of the electrode microstructure in the performance of different energy storage devices. The introduction of a PNM bridges the gap between volume-averaged continuum models and detailed the pore-scale models. The main advantage of this model is the ability to visually show the concentration and current distributions inside the electrode within a reasonably low computational time. Based on this, this work represents the first visual showcase of how regions limited by low convective flow affect the rate of discharge in an electrode, which is essential for the design of optimum electrode microstructures. The implementation of DC-GANs allows for the first time the fast generation of arbitrarily large synthetic microstructural volumes of n-phases with realistic properties and with periodic boundaries. The fact that the generator constitutes a virtual representation of the real microstructure allows the inclusion of the generator as a function of the input latent space in a closed-loop optimisation process. For the first time, a set of visually realistic microstructures of a LIB cathode with user-specified morphological properties were designed based on the optimisation of the generator’s latent space. The introduction of a closed-loop generation-optimisation approach represents a breakthrough in the design of optimised electrodes since it constitutes a first approach for evaluating the microstructure-performance correlation in a continuous forward and backward process.Open Acces

Value Chain Analysis of Mandarin in Nueva Vizcaya, Philippines

Mandarin production and marketing has developed significantly in recent years. However, the mandarin industry in Nueva Vizcaya, Philippines, a well-known mandarin producer, could not meet local demand for mandarin in terms of quantity and quality. There is a definite need for government to intervene for the industry’s growth and development. To be able to identify the specific intervention, value chain analysis (VCA) was conducted. Primary data was gathered by interviewing key players such as farmers and traders. Farmers were purposively selected from the three highest-producing municipalities. Tracer methodology was employed to determine the other key players along the chain. Secondary data were collected from different agencies. Results show that mandarin in Nueva Vizcaya has five chains. The value added from one node to the next one ranges from PhP2.26 to PhP25.00 per kilogram, with the last node, the retailers, getting the highest net margin. Kasibu, the municipality where the industry is more developed, reported farmers getting a higher value for their mandarin (PhP23.58) than farmers from the two municipalities, Diadi (PhP6.87) and Quezon (PhP10.21). Mandarin from Kasibu likewise had a longer chain, showing more marketing activities, and the mandarin reaching other provinces and regions. The study produced four recommended interventions: capability building of farmer associations, forming farmers into production clusters for standardized production and marketing practices, management by using a package of technology, and continuous R&D on the enhancement of the mandarin industry from input provision to postharvest practices

Fast-tracking the Development of the Mandarin Industry of Nueva Vizcaya, Philippines: The Case of the Malabing Valley Multipurpose Cooperative

Nueva Vizcaya is one of the most prolific mandarin-producing provinces in the Philippines. However, it hasn’t developed to international standards, hence the need for government intervention. The Aquino administration came up with the Philippines Rural Development Project (PRDP), a project to fast-track the development of certain industries and commodities, and mandarin was selected for Nueva Vizcaya. To identify priority areas that need intervention, the value chain analysis (VCA) for mandarin in Nueva Vizcaya was conducted. It was found that along the value chain for mandarin, one cooperative stood out, the Malabing Valley Multipurpose Cooperative (MVMPC). The cooperative was purposely organized to support the mandarin industry. VCA found that MVMPC played a major role from input provision such as seedlings, chemical inputs, fertilizers, to marketing of mandarin. One of the recommendations of the VCA was the formation of clusters to produce uniform quality fruits acceptable by consumers and another was the identification of an organization that will carry out the recommendations. MVMPC was selected based on certain criteria. Hence, MVMPC became the proponent group for two enterprises that the provincial government of Nueva Vizcaya envisioned to have. The enterprises are mandarin seedling production and mandarin marketing enterprise. The mandarin seedling production will provide quality planting material while the marketing enterprise will market fresh mandarins bought from production clusters. This proposal amounts to PhP19,487,869, which was submitted to the World Bank for funding.