Marginally trapped submanifolds in Lorentzian space forms and in the Lorentzian product of a space form by the real line

We give local, explicit representation formulas for n-dimensional spacelike submanifolds which are marginally trapped in the Minkowski space, the de Sitter and anti de Sitter spaces and the Lorentzian products of the sphere and the hyperbolic space by the real line.Comment: 20 pages. Third version: a few corrections have been done. The bibliography has been update

Magnetic exchange mechanism for electronic gap opening in graphene

We show within a local self-consistent mean-field treatment that a random distribution of magnetic adatoms can open a robust gap in the electronic spectrum of graphene. The electronic gap results from the interplay between the nature of the graphene sublattice structure and the exchange interaction between adatoms.The size of the gap depends on the strength of the exchange interaction between carriers and localized spins and can be controlled by both temperature and external magnetic field. Furthermore, we show that an external magnetic field creates an imbalance of spin-up and spin-down carriers at the Fermi level, making doped graphene suitable for spin injection and other spintronic applications.Comment: 5 pages, 5 figure

A weighted sustainability index for selection of optimal operating plans

The Wimmera Mallee Pipeline Project (WMPP) provides reticulated water to 36 towns and about 6000 farms across an area of approximately 2 million hectares and forms part of the Wimmera-Mallee Water Supply System (WMWSS). The WMWSS is a multi-reservoir system located in Western Victoria (Australia) which is operated to meet a range of conflicting interests for water using complex operating rules. Since completion in 2010, the pipeline has vastly improved efficiencies in the supply of water, with water savings being returned to the environment, existing consumptive use and new development. However, one of the major challenges for managers of these water recovery projects is to determine the most effective or optimal operational strategy to meet the needs of all water users. In Victoria, these often conflicting interests to water have traditionally been addressed through a consultative process supported by surface water simulation modelling. Simulation models attempt to represent all the major characteristics of a system and are suited to examine “what if?” scenarios. Whilst such models are highly effective in demonstrating the effect of changes in system operation, the modelling process is limited to finding one solution at a time for a given set of conditions. Optimisation models have also proven to be effective tools but unlike simulation models are characterised by a numeric search technique and are better suited to address “what should be?” questions. In recent times there has been growing interest in linking optimisation techniques with simulation models in order to build on the strengths of both modelling approaches in the search for optimal solutions. The general structure of this combined modelling technique provides for an iterative process; simulation outputs are used to quantify the effect of candidate solutions which are in turn passed to the search engine to find optimal solutions. The process of selecting the most preferred optimal solution brings together two aspects of multi-objective optimisation, namely; (i) the quantitative characteristics of these solutions relative to other solutions; and (ii) the higher level qualitative information in the form of stakeholders’ preferences. The aim of this study is to incorporate stakeholder preferences into a sustainability index which has been previously used to evaluate and compare optimal operating plans for the WMWSS. In that previous study, Godoy et al. (2015) applied a multi-objective optimisation and sustainability assessment approach to an 18-objective function multi-objective optimisation problem (MOOP) which represented a range of interests for water. For the present study, the same interests are described in terms of three broad categories i.e. strong environmental preferences, strong social preferences, and strong preferences for the needs of consumptive users. A weighted sustainability index is presented which incorporates these preferences in the original sustainability index formulation. This weighted sustainability index is used to select preferred optimal operating plans previously found by the optimisation-simulation modelling. The results showed that the weighted sustainability index provided a simple means to incorporate stakeholders’ preferences into the selection process and inform the decision maker of a stakeholder’s uncertainty about their values and priorities for water. © 2017 Proceedings - 22nd International Congress on Modelling and Simulation, MODSIM 2017. All rights reserved

Testing the robustness of optimal operating plans under various future hydro-climatic scenarios

A key challenge for water resources planning processes around the world is to develop operating plans that are optimal under a range of hydro-climatic conditions. The consequences of such long term planning decisions can vary in terms of the social, economic, and environmental impacts. Given these potential impacts, it is important that operating plans are tested under a range of hydro-climatic conditions to ensure that they are sufficiently robust to withstand future changes in climate. The aim of this study is to present a procedure for testing the robustness of optimal operating plans for complex water resources systems using a combined multi-objective optimisation and sustainability assessment approach. The approach embeds an optimisation-simulation (O-S) model which is applied to an 18-objective function multi-objective optimisation problem of the Wimmera-Mallee Water Supply System (WMWSS). The WMWSS is a multi-reservoir system located in Western Victoria (Australia) which is operated to meet a range of competing interests for water using complex operating rules. The O-S model is applied to the WMWSS to search for optimal operating plans over a 100-year period into the future assuming two plausible greenhouse gas (GHG) emission levels. The two GHG emission scenarios represent lower and higher ends of the estimated range of projected GHG emissions, providing a wide range of future hydro-climatic conditions. A robustness test is used to evaluate the validity of the most sustainable optimal operating plans under the two GHG emmission scenarios and also those found previously under a historic hydro-climatic sequence. The test results show that the status quo or base case operating plan is optimal but is neither the highest nor the lowest in terms of the level of sustainability that could be achieved in the WMWSS, under historic and the higher GHG emission scenario. Moreover, the results show that the most sustainable optimal operating plans found under the three hydro-climatic scenarios are sufficiently robust to withstand the full range of hydro-climatic conditions considered whereas the base case operating plan is not as robust. The risks involved in the implementation of operating plans which exhibit large deviations from the base case operating plan are discussed. These risks highlight the importance of problem formulation and sensitivity analysis of the optimal operating plans in order to find real world solutions to real world problems. © CURRAN-CONFERENCE. All rights reserved

Chips de mandioca.

A mandioca (Manihot esculenta Crantz) é a base energética da alimentação em vários países tropicais e desempenha um importante papel no âmbito da agricultura familiar, principalmente no Nordeste. Contudo, um dos maiores obstáculos para a maior utilização da mandioca é a sua alta pereciblidade, pois quando armazenada em condições ambientais, possui vida útil muito restrita. Estima-se que 23% da produção de raízes de mandioca são perdidas após a colheita no Brasil, devido ao desconhecimento de técnicas adequadas de processamento e armazenamento. Dessa forma, o desenvolvimento de novas tecnologias de processamento dessas raízes, pode proporcionar a oferta de produtos de maior valor agregado, pouco perecíveis e de grande aceitação pelo mercado consumidor, a exemplo dos chips de mandioca.bitstream/item/86804/1/CHIPS-DE-MANDIOCAid26711.pd

Mandioca chips com teor reduzido de óleo.

bitstream/item/39328/1/circular-101.pd

Controle biológico de percevejos fitófagos da soja na região de Dourados, MS.

Este trabalho teve como objetivo avaliar o parasitismo natural que ocorre em adultos e em ovos do percevejo-marrom da soja Euschistus heros (Fabricius), bem como multiplicar o parasitóide Telenomus podisi (Ashmead) e liberá-lo em lavouras de soja, visando ao controle biológico do percevejo nesta cultura. Durante a safra 2004/2005 e 2005/2006 e nas entressafras de 2004, 2005 e 2006 foram coletados adultos do percevejo, enquanto nas safras de 2003/2004 e 2004/2005 foram coletadas massas de ovos do inseto durante o período reprodutivo da sojabitstream/item/38732/1/BP200740.pdfDocumento on-line

Adaptive Selection of the Optimal Strategy to Improve Precision and Power in Randomized Trials

Benkeser et al. demonstrate how adjustment for baseline covariates in randomized trials can meaningfully improve precision for a variety of outcome types. Their findings build on a long history, starting in 1932 with R.A. Fisher and including more recent endorsements by the U.S. Food and Drug Administration and the European Medicines Agency. Here, we address an important practical consideration: *how* to select the adjustment approach -- which variables and in which form -- to maximize precision, while maintaining Type-I error control. Balzer et al. previously proposed *Adaptive Prespecification* within TMLE to flexibly and automatically select, from a prespecified set, the approach that maximizes empirical efficiency in small trials (N$<$40). To avoid overfitting with few randomized units, selection was previously limited to working generalized linear models, adjusting for a single covariate. Now, we tailor Adaptive Prespecification to trials with many randomized units. Using $V$-fold cross-validation and the estimated influence curve-squared as the loss function, we select from an expanded set of candidates, including modern machine learning methods adjusting for multiple covariates. As assessed in simulations exploring a variety of data generating processes, our approach maintains Type-I error control (under the null) and offers substantial gains in precision -- equivalent to 20-43\% reductions in sample size for the same statistical power. When applied to real data from ACTG Study 175, we also see meaningful efficiency improvements overall and within subgroups.Comment: 10.5 pages of main text (including 2 tables, 2 figures) + 14.5 pages of Supporting Inf

Tolerância ao estresse por déficit hídrico de genótipos de Brachiaria brizantha.

O conhecimento dos mecanismos fisiológicos de resposta às condições de estresse por déficit hídrico poderá auxiliar no desenvolvimento de gramíneas forrageiras mais eficientes no uso da água. O objetivo deste experimento foi classificar genótipos de Brachiaria brizantha quanto ao grau de adaptação ao estresse por déficit hídrico. O experimento foi desenvolvido em casa-de-vegetação, na Embrapa Pecuária Sudeste