Aplicação de um modelo de simulação do desenvolvimento da batateira à cultura da batata primor na região do Oeste

Apresenta-se um modelo de simulação do desenvolvimento da batateira aplicado ao caso particular da batata-primor na região do Oeste. Comparam-se os resultados do modelo com observações de campo efectuadas no concelho da Lourinhã, no ano de 1987, para a variedade Spunta em três densidades de plantação. Finalmente apresentam-se as potencialidades de utilização do modeloinfo:eu-repo/semantics/publishedVersio

Crescimento e produção da cultura de batata primor na região Oeste. I) Análise comparativa do crescimento e produção em três densidades de população

Parte Iinfo:eu-repo/semantics/publishedVersio

Crescimento e produção da cultura de batata primor na região do Oeste. II) Validação de campo do modelo POTATO.2

Parte IIinfo:eu-repo/semantics/publishedVersio

Estimation de la surface foliaire principale et secondaire d’un sarment de vigne

Dans ce travail on présente des modèles empiriques pour estimer, de façon directe et non destructive, la surface foliaire principale et secondaire d’un sarment de vigne pour quatre cépages portugaises. La surface d’une feuille a été estimée avec un modèle basé sur la forte corrélation entre la somme des longueurs des deux premières nervures latérales et la surface foliaire. Pour l’estimative de la surface foliaire principale d’un sarment on a développé un modèle a partir d’une régression multiple de quatre variables explicatives: longueur du sarment, nombre de feuilles principales et surface foliaire de la feuille majeure et mineure. Pour la surface foliaire secondaire on propose un modèle similaire mais en considérant chaque entrecoeur comme une feuille composé. Ce modèle utilise comme variables explicatives le nombre de feuilles secondaires, le nombre d’entrecoeurs et la surface foliaire et nombre de feuilles de l‘entrecoeur major et minore. La surface foliaire de chacun de ces deux entrecoeurs est estimé avec un modèle similaire a celui proposé pour les feuilles principales mais sans la longueur du rameau. Ces modèles ont été validés avec des données indépendants d’un échantillon de sarments prélevés périodiquement dans la saison. D’après les bons résultats de la validation on peut dire que, avec ces modèles, on peut estimer rapidement la surface foliaire total d’un sarment, de façon non destructive et avec une bonne précisioninfo:eu-repo/semantics/publishedVersio

Potential geographic distribution and conservation of Audubon's Shearwater, Puffinus lherminieri in Brazil

A pardela-de-asa-larga (Puffinus lherminieri Lesson 1839) é uma ave marinha tropical que ocorre entre o sul do Canadá e a costa sudeste do Brasil. Puffinus lherminieri é considerado Criticamente Ameaçado na lista vermelha do Brasil principalmente porque ocorre somente em duas localidades, ambas contendo pequenas populações. Porém, muitas ilhas ao longo da costa Brasileira são pouco conhecidas e a descoberta de novas colônias pode ser significativa para a conservação desta espécie. O objetivo deste estudo foi estimar a distribuição geográfica potencial da pardela-de-asa-larga no Brasil, baseada em modelagem de nicho ecológico (MNE) usando o algorítimo Maxent com camadas obtidas do banco de dados ambientais AquaMaps. A MNE foi baseada em 37 registros de áreas de reprodução nas Américas do Norte e Sul. O modelo mostrou uma ampla distribuição potencial, cobrindo a maior parte da costa Atlântica do Brasil e EUA. Quando filtrada para as ilhas ao longo da costa Brasileira o modelo indicou altos níveis de adequação ambiental próximo aos estados de São Paulo, Rio de Janeiro, Espírito Santo e Bahia. Porém, P. lherminieri prefere ilhas em ambientes com água quente e salina. Então, baseado na influência das correntes que atuam na costa Brasileira nós podemos inferir que colônias são mais prováveis de ocorrer em ilhas da costa da Bahia, Espírito Santo e extremo norte do Rio de Janeiro. Estas devem ser intensamente pesquisadas enquanto as ilhas ao sul de Cabo Frio devem ser descartadas. A existência de novas populações pode ter profundos efeitos no estado de conservação desta ave marinha enigmática e raramente vista.Audubon's Shearwater (Puffinus lherminieri Lesson 1839) is a tropical seabird occurring mainly between southern Canada and the southeast coast of Brazil. Puffinus lherminieri is considered Critically Endangered on the Brazilian Red List because it only occurs in two known localities, both of which contain very small populations. However, many offshore islands along the Brazilian coast are poorly known and the discovery of new colonies would be of considerable significance for the conservation of this species. The aim of this study was to estimate the potential geographic distribution of Audubon's Shearwater in Brazil, based on ecological niche model (ENM) using Maxent algorithm with layers obtained from AquaMaps environmental dataset. The ENM was based on 37 records for reproduction areas in North and South America. The model yielded a very broad potential distribution, covering most of the Atlantic coast ranging from Brazil to the US. When filtered for islands along the Brazilian coast, the model indicates higher levels of environmental suitability near the states of São Paulo, Rio de Janeiro, Espírito Santo and Bahia. However, P. lherminieri prefers islands in environments with warm saline water. Thus, based on the influence of currents that act on the Brazilian coast we can infer undiscovered colonies are most likely to occur on islands on coast of Bahia, Espírito Santo and extreme north of the Rio de Janeiro. These should be intensively surveyed while the islands south of Cabo Frio should be discarded. The existence of new populations would have profound effects on the conservation status of this enigmatic and rarely seen seabird

SIAMVITI – Viticultura portuguesa num cenário de alterações climáticas: Impactos e medidas de adaptação

info:eu-repo/semantics/publishedVersio

Impacts of deforestation on plant-pollinator networks assessed using an agent based model.

Plant-pollinator networks have been widely used to understand the ecology of mutualistic interactions between plants and animals. While a number of general patterns have been identified, the mechanisms underlying the structure of plant-pollinator networks are poorly understood. Here we present an agent based model (ABM) that simulates the movement of bees over heterogeneous landscapes and captures pollination events, enabling the influence of landscape pattern on pollination networks to be explored. Using the model, we conducted a series of experiments using virtual landscapes representing a gradient of forest loss and fragmentation. The ABM was able to produce expected trends in network structure, from simulations of interactions between individual plants and pollinators. For example, results indicated an increase in the index of complementary specialization (H2') and a decline in network connectance with increasing forest cover. Furthermore, network nestedness was not associated with the degree of forest cover, but was positively related to forest patch size, further supporting results obtained in the field. This illustrates the potential value of ABMs for exploring the structure and dynamics of plant-pollinator networks, and for understanding the mechanisms that underlie them. We attribute the results obtained primarily to a shift from specialist to generalist pollinators with increasing forest loss, a trend that has been observed in some field situations

Twistors and Black Holes

Motivated by black hole physics in N=2, D=4 supergravity, we study the geometry of quaternionic-Kahler manifolds M obtained by the c-map construction from projective special Kahler manifolds M_s. Improving on earlier treatments, we compute the Kahler potentials on the twistor space Z and Swann space S in the complex coordinates adapted to the Heisenberg symmetries. The results bear a simple relation to the Hesse potential \Sigma of the special Kahler manifold M_s, and hence to the Bekenstein-Hawking entropy for BPS black holes. We explicitly construct the ``covariant c-map'' and the ``twistor map'', which relate real coordinates on M x CP^1 (resp. M x R^4/Z_2) to complex coordinates on Z (resp. S). As applications, we solve for the general BPS geodesic motion on M, and provide explicit integral formulae for the quaternionic Penrose transform relating elements of H^1(Z,O(-k)) to massless fields on M annihilated by first or second order differential operators. Finally, we compute the exact radial wave function (in the supergravity approximation) for BPS black holes with fixed electric and magnetic charges.Comment: 47 pages, v2: typos corrected, reference added, v3: minor change

Experimental bladder carcinogenesis – rodent models

Several rodent models of bladder cancer development have been established. The aim of this review article is to provide a critical assessment of different animal models available for the study of bladder carcinogenesis, its chemoprevention and therapy. All, except for transgenic and knockout animals, require 8–12 months experimental periods in order to generate a high yield of neoplasias. Spontaneous bladder tumor models are extremely rare. The significance of the results from animal experiments is dependent upon the selection of a suitable animal model. There are no rules regarding the choice of a model, it is however very useful to have knowledge of relevant comparative medical aspects concerning this subject. We describe chemical carcinogens most commonly used to induce bladder cancer, pellet implantation and urinary calculi, agents that promote bladder cancer, and irradiation. We also evaluated other tools such as cell cultures, tumor implantation and transgenic models for bladder cancer, that have been developed to study the process. The review considers how several imaging techniques can be applied to study rodent bladder carcinogenesis.Для изучения механизмов развития рака мочевого пузыря было создано несколько экспериментальных моделей на гры- зунах. Целью обзора была сравнительная оценка различных экспериментальных моделей для изучения канцерогенеза мочевого пузыря, профилактики и терапии. За исключением трансгенных и нокаутных животных, для получения высокого выхода опухолей в любой экспериментальной модели требуется 8–12 мес. Модели спонтанного канцерогенеза мочевого пузыря крайне редки. Выбор экспериментальной модели с определенными параметрами определяет значимость получен- ных результатов. В статье описаны различные методики, используемые для индукции рака мочевого пузыря in vivo, ряд методических подходов, таких как культура клеток, имплантация опухоли и трансгенные модели рака мочевого пузыря и современные методы мониторинга опухолевой прогрессии