The effect of treefall gaps on the spatial distribution of three invasive plants in a mature upland forest in Maryland1,2

O objetivo desse trabalho foi analisar a estrutura diamétrica e espacial das espécies Manilkara huberi (Ducke) A. Chev. e Dinizia excelsa Ducke. A distribuição diamétrica foi determinada conforme a metodologia de Sturges. O modelo de Meyer foi ajustado para estimar o número de indivíduos por classe de diâmetro. O padrão de distribuição espacial foi estimado por meio do índice de Morisita. Foram encontrados 1.372 indivíduos de M. huberi, onde os dados de sua estrutura diamétrica foram divididas em 11 classes com intervalo de 6,58 cm. Em relação à espécie D. excelsa, foram encontrados 100 indivíduos e seus dados geraram 7 classes diamétricas com 12 cm de intervalo. A distribuição diamétrica dos indivíduos de M. huberi seguiu a distribuição em “J-invertido”, que é típica das florestas naturais inequiâneas, com um quociente “q” estimado de 1,39. Já os indivíduos da espécie D. excelsa apresentaram-se desbalanceados em todos os centros de classes, não seguindo a tendência de “J-invertido”, e um quociente “q” estimado de 1,22. Quanto à distribuição espacial, observou-se por meio do índice de Morisita que ambas as espécies seguem uma distribuição agrupada em que os indivíduos localizam-se próxima à planta mãe, portanto, as populações tendem a ser agrupadas. As espécies possuem distribuição espacial agregado, subsidiando a exploração das árvores com aptidão ao manejo, observando possíveis ressalvas para a espécie M. huberi.Palavras-chave: quociente De Liocourt; índice de Morisita; floresta ombrófila. POPULATION STRUCTURE OF Manilkara huberi (Ducke) A. Chev. AND Dinizia excelsa Ducke IN AN UPLAND FOREST IN AMAPA ABSTRACT: The aim of this work was to analyze the diametric and spatial structure of the Manilkara huberi (Ducke) A. Chev. and Dinizia excelsa Ducke species. The diameters distribution was determined according to the Sturges methodology. The Meyer model was adjusted to estimate the number of individuals per diameter class. The spatial distribution pattern was estimated using the Morisita index. We found 1,372 individuals of M. huberi, where the data of their diametric structure were divided into 11 classes with an interval of 6.58 cm. In relation to specie D. excelsa, we found 100 individuals and their data generated 7 diameter classes with 12 cm interval. The diameter distribution of M. huberi individuals followed the J-inverted distribution, which is typical of uneven-aged natural forest, with an estimated "q" quotient of 1.39. On the other hand, the individuals of the D. excelsa species showed unbalanced in all class centers, not following the J-inverted distribution and estimated “q” quotient of 1.22. As for the spatial distribution, it was observed through the Morisita index that both species follow a grouped distribution in which the individuals are located close to the mother plant, therefore, the populations tend to be grouped. The species have an aggregate spatial distribution, subsidizing the exploitation of trees with aptitude for management, observing possible caveats for M. huberi specie.Keywords: De Liocourt quotient; Morisita index; ombrophylous forest.

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A influência da distribuição espacial na qualidade do fuste de Euxylophora paraensis (Huber) em floresta de terra firme manejada na Amazônia Oriental / The influence of spatial distribution on the stem quality of Euxylophora paraensis (Huber) in a managed upland forest in the Eastern Amazon

Brazilian Journal of Development ◽

10.34117/bjdv7n8-565 ◽

2021 ◽

Vol 7 (8) ◽

pp. 84130-84146

Author(s):

Thiago Alan Ferreira Da Silva ◽

Alessandra Daniele de Sousa Brandão ◽

Artur Vinícius Ferreira Dos Santos ◽

Brenda Karina Rodrigues Da Silva ◽

Daynara Costa Vieira ◽

...

Keyword(s):

Spatial Distribution ◽

Terra Firme ◽

Upland Forest ◽

Stem Quality

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Modelling and validation of the spatial distribution of suitable habitats for the recruitment of invasive plants on climate change scenarios: An approach from the regeneration niche

The Science of The Total Environment ◽

10.1016/j.scitotenv.2021.146007 ◽

2021 ◽

pp. 146007

Author(s):

Francisco A. Guerra-Coss ◽

Ernesto I. Badano ◽

Isaac E. Cedillo-Rodríguez ◽

Jorge E. Ramírez-Albores ◽

Joel Flores ◽

...

Keyword(s):

Climate Change ◽

Spatial Distribution ◽

Invasive Plants ◽

Regeneration Niche ◽

Climate Change Scenarios ◽

Suitable Habitats

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Seed shadow, seedling recruitment, and spatial distribution of Buchenavia capitata (Combretaceae) in a fragment of the Brazilian Atlantic Forest

Brazilian Journal of Biology ◽

10.1590/s1519-69842006000500014 ◽

2006 ◽

Vol 66 (3) ◽

pp. 883-890 ◽

Cited By ~ 7

Author(s):

B. A. Santos ◽

F. P. L. Melo ◽

M. Tabarelli

Keyword(s):

Spatial Distribution ◽

Atlantic Forest ◽

Seedling Recruitment ◽

Local Population ◽

Forest Understory ◽

Seedling Mortality ◽

Long Distance ◽

Seed Shadow ◽

Treefall Gaps ◽

Suitable Habitats

Here we describe the seed shadow, seedling recruitment, ontogenetic structure and spatial distribution of Buchenavia capitata (an emergent canopy tree) in a 380-ha fragment of the Atlantic forest in northeast Brazil. In particular, we examine seed distribution around 10 parental trees and both seedling recruitment and mortality, during an 18 month period beneath and around parental trees. Moreover, we describe: (1) B. capitata occurrence within treefall gaps; (2) population structure in terms of ontogenetic stages for the whole site; and (3) spatial distribution of adults within an area of 51 hectares. 99% of seeds were found beneath parent crowns (n = 4,236) and seed density reached 14.6 ± 29.9 seeds/m² (0-140 seeds/m²). 49% of all seeds germinated but seedling mortality reached 100% after an 18 month period. In addition, saplings of B. capitata were not found in forest understory and within 30 treefall gaps (94-2,350 m²). The adults showed an average DBH of 69.3 ± 22.1 cm, were 19.2 ± 2.9 m tall and presented a clumped spatial distribution. B. capitata matched some of the features presented by shade intolerant trees or large-gap specialists, and we hypothesize that low rates or even lack of long distance seed dispersal events may be reducing the probability of B. capitata seeds reaching suitable habitats for successful seedling recruitment and growth. Because of that (1) seedlings face high levels of early mortality; (2) there is no sapling recruitment at the study site; and (3) local population faces senility and it is threatened by local extinction.

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Lithography below 100 nm

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100074367 ◽

1983 ◽

Vol 41 ◽

pp. 96-99

Author(s):

L. D. Jackel

Keyword(s):

Spatial Distribution ◽

Electron Beam ◽

Electron Scattering ◽

Electron Beam Lithography ◽

Substrate Material ◽

Local Electron ◽

Electron Dose ◽

Positive Resist ◽

Exposure Process

Most production electron beam lithography systems can pattern minimum features a few tenths of a micron across. Linewidth in these systems is usually limited by the quality of the exposing beam and by electron scattering in the resist and substrate. By using a smaller spot along with exposure techniques that minimize scattering and its effects, laboratory e-beam lithography systems can now make features hundredths of a micron wide on standard substrate material. This talk will outline sane of these high- resolution e-beam lithography techniques.We first consider parameters of the exposure process that limit resolution in organic resists. For concreteness suppose that we have a “positive” resist in which exposing electrons break bonds in the resist molecules thus increasing the exposed resist's solubility in a developer. Ihe attainable resolution is obviously limited by the overall width of the exposing beam, but the spatial distribution of the beam intensity, the beam “profile” , also contributes to the resolution. Depending on the local electron dose, more or less resist bonds are broken resulting in slower or faster dissolution in the developer.

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SEM evaluation of the TEM cold-stage double-film specimen

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100111471 ◽

1984 ◽

Vol 42 ◽

pp. 272-273

Author(s):

Jayesh Bellare

Keyword(s):

Spatial Distribution ◽

Sample Preparation ◽

Sample Thickness ◽

Specimen Preparation ◽

Preparation Technique ◽

Liquid Sample ◽

Thin Specimen ◽

Sample Preparation Technique ◽

Cold Stage ◽

Film Specimen

Seeing is believing, but only after the sample preparation technique has received a systematic study and a full record is made of the treatment the sample gets.For microstructured liquids and suspensions, fast-freeze thermal fixation and cold-stage microscopy is perhaps the least artifact-laden technique. In the double-film specimen preparation technique, a layer of liquid sample is trapped between 100- and 400-mesh polymer (polyimide, PI) coated grids. Blotting against filter paper drains excess liquid and provides a thin specimen, which is fast-frozen by plunging into liquid nitrogen. This frozen sandwich (Fig. 1) is mounted in a cooling holder and viewed in TEM.Though extremely promising for visualization of liquid microstructures, this double-film technique suffers from a) ireproducibility and nonuniformity of sample thickness, b) low yield of imageable grid squares and c) nonuniform spatial distribution of particulates, which results in fewer being imaged.

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Macroprobe Mode for the Study of Segregation in Steels

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100134909 ◽

1990 ◽

Vol 48 (2) ◽

pp. 260-261

Author(s):

Auclair Gilles ◽

Benoit Danièle

Keyword(s):

Mechanical Properties ◽

Spatial Distribution ◽

High Performance ◽

Volume Fraction ◽

Sheet Steel ◽

Acquisition Time ◽

Chemical Information ◽

X Ray ◽

Accurate Quantitative Analysis ◽

Optical Micrographs

During these last 10 years, high performance correction procedures have been developed for classical EPMA, and it is nowadays possible to obtain accurate quantitative analysis even for soft X-ray radiations. It is also possible to perform EPMA by adapting this accurate quantitative procedures to unusual applications such as the measurement of the segregation on wide areas in as-cast and sheet steel products.The main objection for analysis of segregation in steel by means of a line-scan mode is that it requires a very heavy sampling plan to make sure that the most significant points are analyzed. Moreover only local chemical information is obtained whereas mechanical properties are also dependant on the volume fraction and the spatial distribution of highly segregated zones. For these reasons we have chosen to systematically acquire X-ray calibrated mappings which give pictures similar to optical micrographs. Although mapping requires lengthy acquisition time there is a corresponding increase in the information given by image anlysis.

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Ultrastructural analysis of the spatial distribution of MRNA

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100123167 ◽

1992 ◽

Vol 50 (1) ◽

pp. 552-553

Author(s):

Gary Bassell ◽

Robert H. Singer

Keyword(s):

Electron Microscopy ◽

Spatial Distribution ◽

In Situ Hybridization ◽

High Resolution ◽

Nucleic Acids ◽

Colloidal Gold ◽

Dna Probe ◽

Nucleotide Analogs ◽

Gold Particles

We have been investigating the spatial distribution of nucleic acids intracellularly using in situ hybridization. The use of non-isotopic nucleotide analogs incorporated into the DNA probe allows the detection of the probe at its site of hybridization within the cell. This approach therefore is compatible with the high resolution available by electron microscopy. Biotinated or digoxigenated probe can be detected by antibodies conjugated to colloidal gold. Because mRNA serves as a template for the probe fragments, the colloidal gold particles are detected as arrays which allow it to be unequivocally distinguished from background.

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