3,257 research outputs found

    An Evolutionary Analysis of Investment in Electricity Markets

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    Electricity markets are being liberalised and open to private competition in several countries. These liberalized electricity markets are very complex as the interactions between demand and supply are subject to several technicalities arising from the commodity being traded: electricity. One of these technicalities is that generators cannot store electricity: this fact implies that it needs to generate its production real-time. A second problem with this market are the different generation technologies used at different levels of demand, which implies that at different times of the day different generation costs are supported to meet demand: due to ramp-rate constraints, capacity available, and fixed and start-up costs. In this paper we analyze the issue of investment and the electricity system’s long-term security in an industry where a regulator controls the short-term prices, imposing a perfect competition outcome for “low†demand hours and a price cap at times where load is shed. We look at the following research questions: a) How does the oligopolistic structure of the market interact with the value of the different technologies? b) How do players define their investment strategies? c) How do the regulatory policies affect the investment in generation? Do they work similarly under perfect competition and oligopoly? d) Can markets invest enough capacity to ensure the long run security of the market? The main results of our analysis are following: 1. The impact of a given investment on the market price is independent of the player investing. 2. The impact of an investment on price is a function of the technology in which the investment takes place and of the cycle to which the price refers to. 3. The impact of price caps on the evolution of the market structure is non-linear, it cannot be too low or too high. 4. An oligopolistic electricity market fails to deliver the needed investment unless the regulators intervene. 5. The higher the reserve margin the higher the total investment. However, this instrument by itself was not able to provide the incentive needed to ensure the long-term security of the system, as in any of the experiments analyzed the peak demand is not completely satisfied. 6. Even a slight increase in demand, due to the reserve margin, leads to important changes on the relative value of the different technologies. 7. The main task of the regulatory authorities is to define a level of capacity payments that give the necessary incentive to investment, at the minimum cost: Capacity Payments are very important in shaping the generation structure. 8. Uncertainty reduces the value of Peak plants: this result clearly contradicts any common sense in these matters, as one would expect the presence of price uncertainty to be beneficial to Peak plants. The proportion invested in baseload plants increases with uncertainty of the energy price, decreasing the investment in shoulder plant.agent-based, electricity markets, evolution, investment, regulation, simulation

    Introducing programming to basic schools students using robotics

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    The present work reports on the development of programming activities with students from the 1st and 2nd cycles of schools in the town of Braga in the northwestern Portuguese region of Minho. These activities of promotion of computer programming were applied in order to promote the programming and innovative practices on science and technology education. The explored interdisciplinary methodologies in STEM teaching-learning processes, stimulate critical thinking and creativity while promoting the benefits of learning in collaborative environments. The active involvement of the students in these robot programming, “high tech” and trendy, activities is easy to achieve if the proposed challenges are set at an adequate level of difficulty and appealing enough to the age group and level of cognitive development of the student. Whenever possible to the students is given the possibility of choosing or even defining the problem/subject they will be exploring by programming a robot, which is seen as a mechanical artificial being the students will be able to understand, interact with and use and control. The teacher/educator should be available to provide to the students a proper empowering environment and to provide all support requested by the students giving, as much as possible, not straight answers but yes clues and small hints and examples leading the students to reach, themselves, to a solution to the problem the students face or to an answer to the students’ question that satisfy their own critical judgment. Through the programming testing process, it is possible to verify and see the level of perception and proficiency of the students assessing what students have learned and accomplished, creating immediate feedback for students and adjusting or re-orienting the students’ focus on a particular task or reasoning process. If well succeeded these activities can develop among the students a sound appreaciation towards Science Technology and Engineering while establishing relevant knowledge, creativity critical reasoning abilities and a large number of other competencies that will be valuable for the future development of the students in their studies and academic life but also in their future careers. The improvement of the self-esteem of the students when they realize they can actually “do it” is also a major benefit of this type of activities. As well in what concerns the boost of the self-esteem and selft-appreaciation of their teachers and educators, that often fear to explore this type of innovative approaches

    Quadruped robot locomotion using a global optimization stochastic algorithm

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    The problem of tuning nonlinear dynamical systems parameters, such that the attained results are considered good ones, is a relevant one. This article describes the development of a gait optimization system that allows a fast but stable robot quadruped crawl gait. We combine bio-inspired Central Patterns Generators (CPGs) and Genetic Algorithms (GA). CPGs are modelled as autonomous differential equations, that generate the necessar y limb movement to perform the required walking gait. The GA finds parameterizations of the CPGs parameters which attain good gaits in terms of speed, vibration and stability. Moreover, two constraint handling techniques based on tournament selection and repairing mechanism are embedded in the GA to solve the proposed constrained optimization problem and make the search more efficient. The experimental results, performed on a simulated Aibo robot, demonstrate that our approach allows low vibration with a high velocity and wide stability margin for a quadruped slow crawl gait.This work is funded by FEDER Funding supported by the Operational Program Competitive Factors .U COMPETE and National Funding supported by the FCT Portuguese Science Foundation through project PTDC/EEACRO/100655/200

    Biosynthesis of plant polyphenol compounds with therapeutic and industrial relevance

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    Polyphenols are naturally produced in plants and have several biological and potential therapeutic activities such as anti inflammatory, antioxidant and anticancer They have an estimated market size of USD 2 26 billion by 2027 However, polyphenols are extracted from plants where they accumulate in low amounts over long growth periods In addition, their purification is difficult and expensive since it requires the separation of other compounds with similar chemical structures in an environmentally unfriendly process Heterologous microbial production has several benefits as it is not limited by plant availability or environmental factors and it is a renewable, environmentally friendly and sustainable approach Herein, we report the construction of artificial pathways for the production of curcuminoids and furanocoumarins using Escherichia coli as chassis These compounds can be produced from tyrosine or hydroxycinnamic acids as precursors and have in common the phenylpropanoids pathway Pure curcumin production from ferulic acid achieved 563 mg/L Curcuminoids were also produced from tyrosine 42 mg/L) using a modular pathway combining synthetic biologic and co culture engineering To our knowledge, these are the highest titers of curcuminoids obtained to date CRISPR Cas 9 was used to disrupt the lacZ gene in order to follow co culture population compositionPortuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2020 unit and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund (ERDF) under the scope of Norte2020 - Programa Operacional Regional do Norte. In addition, the authors acknowledge the Biomass and Bioenergy Research Infrastructure (BBRI) – LISBOA-010145- FEDER-022059, supported by Operational Program for Competitiveness and Internationalization (PORTUGAL2020), the Lisbon Portugal Regional Operational Program (Lisboa2020), and Norte2020 under the Portugal 2020 Partnership Agreement, through the ERDF. JR is recipient of a fellowship supported by a doctoral advanced training (SFRH/BD/138325/2018) funded by FCTinfo:eu-repo/semantics/publishedVersio

    Evolution strategies combined with central pattern generators for head motion minimization during quadruped robot locomotion

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    In autonomous robotics, the head shaking induced by locomotion is a relevant and still not solved problem. This problem constraints stable image acquisition and the possibility to rely on that information to act accordingly. In this article, we propose a movement controller to generate locomotion and head movement. Our aim is to generate the head movement required to minimize the head motion induced by locomotion itself. The movement controllers are biologically inspired in the concept of Central Pattern Generators (CPGs). CPGs are modelled based on nonlinear dynamical systems, coupled Hopf oscillators. This approach allows to explicitly specify parameters such as amplitude, offset and frequency of movement and to smoothly modulate the generated oscillations according to changes in these parameters. Based on these ideas, we propose a combined approach to generate head movement stabilization on a quadruped robot, using CPGs and an evolution strategy. The best set of parameters that generates the head movement are computed by an evolution strategy. Experiments were performed on a simulated AIBO robot. The obtained results demonstrate the feasibility of the approach, by reducing the overall head movement

    Portuguese 16th to Early 18th Century tin Glazed Ceramics Found at the Tagus Estuary Saltpans

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    UID/NAN/50024/2019 M-ERA-MNT/0002/2015 UIDB/04209/2020 UIDP/04209/2020Salt was extracted from saltpans, in the South shore of Tagus River by evaporation of the salted sea water which penetrates into the estuary. The walls and the bottom of those saltpans were made of local clays to retain the sea water, and ceramic sherds have been used to endure those walls and also to allow people to walk on the saltpans’ walls. Those sherds constitute an example of the ceramics production in Lisbon workshops, starting in the mid-16th century and reaching high levels of quality in the 17th and 18th century. A detailed archaeometric study of 14 selected sherds dated from the 16th to the early 18th century has been made and the conjugation of the information provided by the micro-Raman, XRD and XRF experiments for those sherds and clays collected locally, allowed us the characterisation of the Lisbon ceramics in that period. Three main groups could be identified in the ceramic bodies; all made with locally collected clays of Miocene origin. In the first group, the potters used raw materials from the clay sources located at Santa Catarina area in Lisbon, most probably mixed with Lapa clays, which were fired at a high temperatures, ranging from 850ºC to 950ºC. Gehlenite and quartz are the dominant minerals of these ceramic bodies. In the second and third groups of Lisbon ceramic bodies, made with Prazeres clays, diopside was also detected but with variable amounts of gehlenite. Clay formations mineralogy mainly include kaolinite, muscovite/illite, quartz, calcite, and feldspars (albite and microcline).publishersversionpublishe

    Multi-objective parameter CPG optimization for gait generation of a quadruped robot considering behavioral diversity

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    This paper presents a gait multi-objective optimization system that combines bio-inspired Central Patterns Generators (CPGs) and a multi-objective evolutionary algorithm. CPGs are modeled as autonomous differential equations, that generate the necessary limb movement to perform the required walking gait. In order to optimize the walking gait, four conflicting objectives are considered, simultaneously: minimize the body vibration, maximize the velocity, maximize the wide stability margin and maximize the behavioral diversity. The results of NSGA-II for this multi-objective problem are discussed. The effect of the inclusion of a behavioral diversity objective in the system is also studied in terms of the walking gait achieved. The experimental results show the effectiveness of this multi-objective approach. The several walking gait solutions obtained correspond to different trade-off between the objectives.This work is funded by FEDER Funding supported by the Operational Program Competitive Factors - COMPETE and National Funding supported by the FCT - Portuguese Science Foundation through project PTDC/EEACRO/ 100655/2008. Thanks to Dr. St ? ephane Doncieux from the Institut des Systmes Intelligents et de Robotique (ISIR) of the Pierre and Marie Curie University (UPMC

    Microbial production of curcumin

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    First Online: 01 October 2022Curcumin, a polyphenol produced by turmeric (Curcuma longa), has attracted increased attention due to its potential as a novel cancer-fighting drug. However, to satisfy the required curcumin demand for health-related studies, high purity curcumin preparations are required, which are difficult to obtain and are very expensive. Curcumin and other curcuminoids are usually obtained through plant extraction. However, these polyphenols accumulate in low amounts over long periods in the plant and their extraction process is costly and not environmentally friendly. In addition, curcumin chemical synthesis is complex. All these reasons limit the advances in studies related to the in vitro and in vivo curcumin biological activities. The microbial production of curcumin appears as a solution to overcome the limitations associated with the currently used methods. Curcumin biosynthesis begins with the conversion of the aromatic amino acids, phenylalanine and tyrosine, into phenylpropanoids, the curcuminoid precursors. The phenylpropanoids are then activated through condensation with a CoA molecule. Afterwards, curcuminoids are synthesized by the action of type III polyketide synthases (PKS) that combine two activated phenylpropanoids and a malonyl-CoA molecule. To engineer microbes to produce curcumin, the curcuminoid biosynthetic genes must be introduced as microorganisms lack the enzymatic reactions responsible to synthesize curcuminoids. In this chapter, the advances regarding the microbial production of curcumin are exposed. The heterologous production of curcumin has been mainly achieved in the bacteria Escherichia coli. However, other microorganisms have already been explored. Besides the introduction of curcumin biosynthetic genes, the optimization of the microbial chassis must also be considered to maximize the production yields. The strategies employed for this purpose are also herein presented. The maximum titer of curcumin produced by a genetically engineered E. coli was 563.4 mg/L with a substrate conversion yield of 100% from supplemented ferulic acid. Moreover, the de novo production of curcumin was accomplished in E. coli reaching 3.8 mg/L of curcumin. Overall, the recent developments on curcumin heterologous production are very encouraging.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/BIO/04469/2020 unit, and by LABBELS – Associate Laboratory in Biotechnology, Bioengineering and Microelectromechnaical Systems, LA/P/0029/2020. J.R. is recipient of a doctoral fellowship (SFRH/BD/138325/2018) supported by a doctoral advanced training funded by FCT.info:eu-repo/semantics/publishedVersio

    CRISPR-Cas9: a powerful tool to efficiently engineer Saccharomyces cerevisiae

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    Saccharomyces cerevisiae has been for a long time a common model for fundamental biological studies and a popular biotechnological engineering platform to produce chemicals, fuels, and pharmaceuticals due to its peculiar characteristics. Both lines of research require an effective editing of the native genetic elements or the inclusion of heterologous pathways into the yeast genome. Although S. cerevisiae is a well-known host with several molecular biology tools available, a more precise tool is still needed. The clustered, regularly interspaced, short palindromic repeats–associated Cas9 (CRISPR-Cas9) system is a current, widespread genome editing tool. The implementation of a reprogrammable, precise, and specific method, such as CRISPR-Cas9, to edit the S. cerevisiae genome has revolutionized laboratory practices. Herein, we describe and discuss some applications of the CRISPR-Cas9 system in S. cerevisiae from simple gene knockouts to more complex processes such as artificial heterologous pathway integration, transcriptional regulation, or tolerance engineering.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/BIO/04469/2020 unit and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund (ERDF) under the scope of Norte2020—North Portugal Regional Program. In addition, this research has been carried out at the Biomass and Bioenergy Research Infrastructure (BBRI)—LISBOA-010145- FEDER-022059, supported by Operational Program for Competitiveness and Internationalization (PORTUGAL2020), the Lisbon Portugal Regional Operational Program (Lisboa2020), and Norte2020 under the Portugal 2020 Partnership Agreement, through the ERDF. J.R. is recipient of a fellowship supported by a doctoral advanced training (SFRH/BD/138325/2018) funded by FCT.info:eu-repo/semantics/publishedVersio
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