Modelagem computacional do crescimento de cana-de-açúcar para predição de produtividade potencial.

Resumo- Neste artigo é apresentado um modelo ecofisiológico-matemático (BrCane) para predizer a produtividade potencial - sem restrições nutricionais ou de água -, a fim de analisar a sustentabilidade da expansão do cultivo de cana-de-açúcar em novas áreas para produção de etanol. A arquitetura do modelo BRCANE foi concebida para uma planta tipo C4, onde a evolução mensal da biomassa foi estimada em função da temperatura do ar e da radiação incidente. Nas simulações apresentadas a produção de biomassa levou em conta a taxa bruta de fotossíntese subtraídas as perdas para respiração de manutenção, senescência de folhas e morte de perfilhos durante o ciclo da cultura. O modelo BRCANE também foi usado para descrever o comportamento fisiológico em função das condições ambientais relacionadas ao tempo termal. A implementação de tais condições permitiu ajustar os resultados das simulações a resultados experimentais disponíveis na literatura. As estimativas de biomassa foram comparadas com dados obtidos durante o ciclo da cultura em experimentos de campo com irrigação (Cultivares RB72 454, NA 56-79, CB 41-76, CB47-355, CP51-22, Q138 e Q141) no Estado de São Paulo (Brasil) e em Bundaberg e Queensland (Austrália) e os resultados foram expressos em toneladas de colmo por hectare (Mg.ha-1), por meio de uma relação linear para cada variedade (R2 = 0,88). O modelo apresentou resultados consistentes com dados experimetais para crescimento de biomassa no ciclo da cultura da cana-de-açúcar.bitstream/item/65018/1/boletim31.pd

Digital control implementation to reduce the cost and improve the performance of the control stage of an industrial switch-mode power supply

Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. D. A. Díez, O. M. García, J. A. Oliver, P. Alou, F. Moreno, B. Duret, J. A. Cobos, F. V. Canales, and A. de Castro, "Digital control implementation to reduce the cost and improve the performance of the control stage of an industrial switch-mode power supply", in 2011 IEEE Energy Conversion Congress and Exposition (ECCE), Phoenix (AZ), 2011, pp. 2930 - 2935The main objective of this work is the design and implementation of the digital control stage of a 280W AC/DC industrial power supply in a single low-cost microcontroller to replace the analog control stage. The switch-mode power supply (SMPS) consists of a PFC boost converter with fixed frequency operation and a variable frequency LLC series resonant DC/DC converter. Input voltage range is 85VRMS-550VRMS and the output voltage range is 24V-28V. A digital controller is especially suitable for this kind of SMPS to implement its multiple functionalities and to keep the efficiency and the performance high over the wide range of input voltages. Additional advantages of the digital control are reliability and size. The optimized design and implementation of the digital control stage it is presented. Experimental results show the stable operation of the controlled system and an estimation of the cost reduction achieved with the digital control stage

Weight-length relationships, weight conversion factors and condition factor trends for two stocks of black anglerfish (Lophius budegassa) in southern Bay of Biscay, Galician waters and northern Atlantic areas from a decade

The weight-length relationship has a wide application in fish biology and fisheries management, such as for predicting weight from length data, or for the calculation of production and biomass of a fish stock. Weight-length relationship, weight conversion factors and condition factor are presented from a decade (2006 to 2015) for both stocks of black anglerfish (Lophius budegassa) in southern Bay of Biscay and Galician waters (ICES Div. VIIIc-IXa, southern stock) and in Celtic Seas (ICES Div. VIIb,c,h,j,k, northern stock). A total of 2035 and 1263 specimens were sampled respectively in each stock from commercial landings and research surveys. Total length [Lt (cm)], total weight [Wt (g)], “commercial” weight (gutted with liver) [Wgl (g)] and “scientific” weight (gutted without liver) [Wg (g)] were obtained. The weight-length relationships for the combined sexes were: Lt = 0.020 Wt2.916; Lt = 0.017 Wgl2.929; Lt = 0.017 Wg2.922 in Div. VIIIc-IXa, and Lt = 0.025 Wt2.841; Lt = 0.013 Wgl2.984; Lt = 0.013 Wg2.971 in Div. VIIb,c,h,j,k. These updated values can be used in the annual assessment of the state of both stocks in the ICES working group, replacing those previous estimated more than a decade ago. The conversion factor (total weight - gutted weight) here estimated is also useful in fisheries management due to the commercial landings of this species are available in gutted weight. The evolution of the condition factor along the year, indicator of nutritional status evolution, is estimated and can be a proxy for estimating the spawning season. Its evolution is studied throughout the year for immature and mature individuals of each sex. The results are similar to the previously estimated in other studies

“Emancipatory circuits of knowledge” for urban equality: experiences from Havana, Freetown, and Asia

Feminist, Southern, and decolonial thinkers have long argued that epistemological questions about how knowledge is produced and whose knowledge is valued and actioned are crucial in addressing inequalities, and a key challenge for plan‐ ning. This collaborative article interrogates how knowledge is mobilised in urban planning and practice, discussing three experiences which have actively centred often‐excluded voices, as a way of disrupting knowledge hierarchies in planning. We term these “emancipatory circuits of knowledge”—processes whereby diverse, situated, and marginalised forms of knowledge are co‐produced and mobilised across urban research and planning, to address inequalities. We discuss expe‐ riences from the Technological University José Antonio Echeverría (CUJAE), a university in Havana, Cuba, that privileges a fluid and collaborative understanding of universities as social actors; the Sierra Leone Urban Research Centre, a research institute in the city of Freetown, which curates collective and inclusive spaces for community action planning, to challenge the legacies of colonial‐era planning; and the Asian Coalition for Housing Rights, a regional network across Asia, which facil‐ itates processes of exchange and co‐learning which are highly strategic and situated in context, to advance community‐led development. Shared across these “emancipatory circuits” are three “sites of impact” through which these partners have generated changes: encouraging inclusive policy and planning outcomes; shifting the planning praxis of authorities, bureau‐ crats, and researchers; and nurturing collective trajectories through building solidarities. Examining these three sites and their challenges, we query how urban knowledge is produced and translated towards epistemic justice, examining the tensions and the possibilities for building pathways to urban equality

Vertex Cover Kernelization Revisited: Upper and Lower Bounds for a Refined Parameter

An important result in the study of polynomial-time preprocessing shows that there is an algorithm which given an instance (G,k) of Vertex Cover outputs an equivalent instance (G',k') in polynomial time with the guarantee that G' has at most 2k' vertices (and thus O((k')^2) edges) with k' <= k. Using the terminology of parameterized complexity we say that k-Vertex Cover has a kernel with 2k vertices. There is complexity-theoretic evidence that both 2k vertices and Theta(k^2) edges are optimal for the kernel size. In this paper we consider the Vertex Cover problem with a different parameter, the size fvs(G) of a minimum feedback vertex set for G. This refined parameter is structurally smaller than the parameter k associated to the vertex covering number vc(G) since fvs(G) <= vc(G) and the difference can be arbitrarily large. We give a kernel for Vertex Cover with a number of vertices that is cubic in fvs(G): an instance (G,X,k) of Vertex Cover, where X is a feedback vertex set for G, can be transformed in polynomial time into an equivalent instance (G',X',k') such that |V(G')| <= 2k and |V(G')| <= O(|X'|^3). A similar result holds when the feedback vertex set X is not given along with the input. In sharp contrast we show that the Weighted Vertex Cover problem does not have a polynomial kernel when parameterized by the cardinality of a given vertex cover of the graph unless NP is in coNP/poly and the polynomial hierarchy collapses to the third level.Comment: Published in "Theory of Computing Systems" as an Open Access publicatio

Income effects, cost damping and the value of time: theoretical properties embedded within practical travel choice models

Mackie et al. (Values of travel time savings in the UK. Report to Department for Transport. Institute for Transport Studies, University of Leeds & John Bates Services, Leeds and Abingdon, 2003) proposed an identity relating the value of time (VoT) for commute and leisure travel to income and travel cost, reporting the prevalence of ‘cost damping’ (i.e. the phenomenon where VoT increases as travel cost increases). This identity (or a variant thereof) has been adopted within official methods for estimating VoT in the UK, Switzerland and The Netherlands. The present paper shows that Mackie et al.’s identity: (i) implies linear preferences, not strictly convex preferences as reported by Mackie et al.; (ii) complies with homogeneity and symmetry by construction; (iii) complies with adding-up if and only if VoT is unit elastic with respect to income; (iv) complies with negativity if VoT is unit elastic or greater with respect to income; (v) violates both adding-up and negativity in the case of the 2003 UK national VoT study. We propose alternative identities which comply with adding-up and homogeneity by construction, and offer comparable fit to Mackie et al.’s identity on the UK VoT dataset. We also find that the imposition of adding-up and negativity on Mackie et al.’s identity, through appropriate constraint on model estimation, leads to an increase of around 20% in valuations from the 2003 UK dataset

Effect of Organic Nutrition in the Nursery Growth and Nutrimental Content of Native Avocados of Ometepec, Guerrero, Mexico

In Mexico, there are several types of wild and criollo avocados that constitute a genetic heritage of this species; these avocados currently grow in an unordered manner on farmer's lands and in backyards, and they need to be studied as they are being lost because of agricultural activities and edaphoclimatic and phytosanitary factors. On the other hand, in orchards and avocado nurseries, high amounts of chemical fertilizers and pesticides are used affecting the physicochemical and microbiological properties of the soil, modifying the flora and fauna and polluting aquifers and springs that cause health problems among consumers. Therefore, it is very important to have a more friendly agriculture with the nature. The aim of this work was to evaluate under nursery conditions, the effect of organic fertilizers on 12 genotypes (rootstocks) of native avocados of Ometepec, Guerrero, Mexico, under an experimental design of random blocks, with four treatments: T1: sheep manure,T2: Bovine manure, T3: mycorrhizae and T4 (control: water) in four replicates. The variables were: plant height (PH), stem diameter (SD), number of leaves: young (NYL) and mature (NML) per plant; and the content of NO3-, K+, Ca2+ and Na+ ions obtained by petiole extraction, and the chlorophyll content measured with SPAD, in young (CYL) and mature (CML) leaves. Additionally, an analysis of variance and Tukey mean tests (P ≤ 0.01 and 0.05) and LSD (P ≤ 0.05) were done. It was found that sheep manure was superior to other treatments in PH (76.7 cm), SD (7.2 mm), NYL (6.5 leaves/plant), NML (18.4 leaves/plant), CML (40.2 SPAD) and Ca2+(1495ppm). In conclusion, the sheep manure was better than the bovine, mycorrhiza and control (water) as it affected positively the behavior of rootstocks in plant height, stem diameter and number of young and mature leaves. In addition, organic nutrition showed no significant response in the chlorophyll content of young and mature leaves. Young leaves only reached 50% of the chlorophyll content compared to mature leaves

Deep sub-threshold Ξ−\Xi^- production in Ar+KCl reactions at 1.76A GeV

We report first results on a deep sub-threshold production of the doubly strange hyperon $\Xi^-$ in a heavy-ion reaction. At a beam energy of 1.76A GeV the reaction Ar+KCl was studied with the High Acceptance Di-Electron Spectrometer (HADES) at SIS18/GSI. A high-statistics and high-purity $\Lambda$ sample was collected, allowing for the investigation of the decay channel $\Xi^- \to \Lambda \pi^-$. The deduced $\Xi^-/(\Lambda+\Sigma^0)$ production ratio of $(5.6 \pm 1.2 ^{+1.8}_{-1.7})\cdot 10^{-3}$ is significantly larger than available model predictions.Comment: 4 pages, including 4 figure