The Complexity of Helly-B1B_{1} EPG Graph Recognition

Golumbic, Lipshteyn, and Stern defined in 2009 the class of EPG graphs, the intersection graph class of edge paths on a grid. An EPG graph $G$ is a graph that admits a representation where its vertices correspond to paths in a grid $Q$, such that two vertices of $G$ are adjacent if and only if their corresponding paths in $Q$ have a common edge. If the paths in the representation have at most $k$ bends, we say that it is a $B_k$-EPG representation. A collection $C$ of sets satisfies the Helly property when every sub-collection of $C$ that is pairwise intersecting has at least one common element. In this paper, we show that given a graph $G$ and an integer $k$, the problem of determining whether $G$ admits a $B_k$-EPG representation whose edge-intersections of paths satisfy the Helly property, so-called Helly-$B_k$-EPG representation, is in NP, for every $k$ bounded by a polynomial function of $|V(G)|$. Moreover, we show that the problem of recognizing Helly-$B_1$-EPG graphs is NP-complete, and it remains NP-complete even when restricted to 2-apex and 3-degenerate graphs

Produção e rendimento de óleo essencial de alecrim de tabuleiro em função da adubação orgânica.

Este trabalho objetivou avaliar a produção e o rendimento de óleo essencial em função da adubação orgânica em Lippia gracilis.Suplemento. Edição dos Anais do 52 Congresso Brasileiro de Olericultura, Salvador, jul. 2012

Cultivo do alecrim do mato no Vale do São Francisco em função da adubação organo-mineral.

Suplemento. Edição dos Anais do 52 Congresso Brasileiro de Olericultura, Salvador, jul. 2012

The Euler characteristic as a topological marker for outbreaks in vector-borne disease

Abstract. Epidemic outbreaks represent a significant concern for the current state of global health, particularly in Brazil, the epicentre of several vector-borne disease outbreaks and where epidemic control is still a challenge for the scientific community. Data science techniques applied to epidemics are usually made via standard statistical and modelling approaches, which do not always lead to reli- able predictions, especially when the data lacks a piece of reliable surveillance information needed for precise parameter estimation. In particular, dengue out- breaks reported over the past years raise concerns for global health care, and thus novel data-driven methods are necessary to predict the emergence of out- breaks. In this work, we propose a parameter-free approach based on geometric and topological techniques, which extracts geometrical and topological invariants as opposed to statistical summaries used in established methods. Specifically, our procedure generates a time-varying network from a time-series of new epidemic cases based on synthetic time-series and real dengue data across several dis- tricts of Recife, the fourth-largest urban area in Brazil. Subsequently, we use the Euler characteristic (EC) to extract key topological invariant of the epidemic time-varying network and we finally compared the results with the effective reproduction number (Rt) for each data set. Our results unveil a strong cor- relation between epidemic outbreaks and the EC. In fact, sudden changes in the EC curve preceding and/or during an epidemic period emerge as a warn- ing sign for an outbreak in the synthetic data, the EC transitions occur close to the periods of epidemic transitions, which is also corroborated. In the real dengue data, where data is intrinsically noise, the EC seems to show a better sign-to-noise ratio once compared to Rt. In analogy with later studies on noisy data by using EC in positron emission tomography scans, the EC estimates the number of regions with high connectivity in the epidemic network and thus has potential to be a signature of the emergence of an epidemic state. Our results open the door to the development of alternative/complementary topological and geometrical data-driven methods to characterise vector-borne disease outbreaks, specially when the conventional epidemic surveillance methods are not effective in a scenario of extreme noise and lack of robustness in the data

Fitorreguladores de crescimento no alongamento in vitro de Pinus greggii.

Organizado por Patricia Póvoa de Mattos, Celso Garcia Auer, Rejane Stumpf Sberze, Katia Regina Pichelli e Paulo César Botosso

Assepsia de sementes para estabelecimento in vitro de espécies medicinais nativas da Caatinga.

Objetivou-se com este trabalho, realizar diferentes testes de assepsia para o estabelecimento in vitro de três espécies nativas da Caatinga de potencial medicinal

Reservas de amido em sarmentos de videira 'Isabel precoce' submetida a diferentes épocas de poda e duas safras no ciclo.

Na região sul do Brasil, onde o clima é temperado, tradicionalmente colhe-se apenas uma safra/ciclo por ano. Alguns locais, como na Depressão Central do RS estão adotando manejo de dupla poda a fim de obter duas safras e oferecendo uma maior viabilidade financeira para o produtor que além de obter uma segunda safra, poderá ofertar em um período de baixa oferta de uva no mercado, recebendo mais pela produção. O objetivo deste trabalho foi avaliar as reservas de amido em sarmentos que se desenvolveram a partir de distintas datas de poda e em videiras com ou sem a prática de dupla colheita. O vinhedo de Isabel Precoce onde foi realizado o experimento está localizado no município de Eldorado do Sul-RS. A quantificação do amido foi por processo enzimático com posterior leitura em espectrofotômetro. Concluiu-se que a precocidade na poda de inverno auxilia no acúmulo de reservas de amido em sarmentos da videira por aumentar o ciclo vegetativo fotossinteticamente ativo das plantas e a dupla poda/colheita reduz os conteúdos de amido presentes no sarmento, principalmente no segundo período de crescimento, podendo debilitar a planta caso esta prática seja associada a podas tardias e realizada em anos sucessivos

Multiplicação in vitrode umburana de cheiro (Amburana cearensis (Allemao A.C. Smith) em função de diferentes concentrações de citocinina.

Objetivou-se com este trabalho, avaliar o efeito de diferentes concentrações de citocinina na multiplicação in vitro de umburana de cheiro

Leaf, Pod and Whole Plant Tannin Contents in Pigeon Pea (\u3cem\u3eCajanus cajan\u3c/em\u3e (L.) Millsp)

Tannin content is an important characteristic of leguminous crops and it has been used as a selection criterion in pigeon-pea improvement programmes (Godoy et al., 1994). In south-eastern Brazil, pigeon pea is often consumed by bovines in the dry season (from April though October), after flowering occurs, and is recommended in some cases, specifically for that time of the year (Lourenço et al., 1994). Since tannin content is being used as a selection criterion and the animals in the dry season preferentially eat pods and leaves, an experiment was conducted to compare whole plant, leaf and pod tannin content