Nonarbitrary Sample Unit

Keyword(s):  
1989 ◽  
Vol 46 (12) ◽  
pp. 2157-2165 ◽  
Author(s):  
Steven P. Ferraro ◽  
Faith A. Cole ◽  
Waldemar A. DeBen ◽  
Richard C. Swartz

Power-cost efficiency (PCEi = (n × c)min/(ni × ci), where i = sampling scheme, n = minimum number of replicate samples needed to detect a difference between locations with an acceptable probability of Type I (α) and Type II (β) error (e.g. α = β = 0.05), c = mean "cost," in time or money, per replicate sample, and (n × c)min = minimum value of (n × c) among the i sampling schemes) is the appropriate expression for comparing the cost efficiency of alternative sampling schemes having equivalent statistical rigor when the statistical model is a redistribution for comparisons of two means. PCEs were determined for eight macrobenthic sampling schemes (four sample unit sizes and two sieve mesh sizes) in a comparison of a reference site versus a putative polluted site in Puget Sound, Washington. Laboratory processing times were, on average, about 2.5 times greater for the [Formula: see text]- than the [Formula: see text] samples. The 0.06-m2, 0- to 8-cm-deep sample unit size and 1.0-mm sieve mesh size was the overall optimum sampling scheme in this study; it ranked first in PCE on 8 and second on 3 of 11 measures of community structure. Rank order by statistical power of the 11 measures for this scheme was Infaunal Index > log10 (mollusc biomass + 1) > number of species > log10 (numerical abundance) > log10 (polychaete biomass + 1) > log10 (total biomass + 1) > log10 (crustacean biomass + 1) > McIntosh's index > 1 – Simpson's Index > Shannon's Index > Dominance Index.


1965 ◽  
Vol 97 (12) ◽  
pp. 1303-1318 ◽  
Author(s):  
H. J. Herbert

AbstractIn Nova Scotia one leaf cluster with an adjoining 1 inch of twig taken from the inside of each of 10 apple trees replicated four times is an adequate sample unit to measure the density of the brown mite.The brown mite has one generation with a partial second in some orchards and one with a partial second and partial third in others. The first generation adults in the bivoltine and trivoltine populations lay summer eggs on the leaves and twigs, and diapause eggs on tin twigs. The second generation adults in the bivoltine populations lay only diapause eggs; in the trivoltine populations they lay both summer and diapause eggs. The adults of the third generation lay only diapause eggs.The brown mite is found on both the leaves and woody parts of the tree. In orchards with bivoltine populations the proportion of mites on leaves reached a peak of 80% by mid-July, but thereafter gradually decreased to 10% by the end of August. However, in orchards with trivoltine populations the proportion of mites on leaves reached a peak of 80 to 90% by mid-July, remained constant until mid-August, and thereafter decreased to approximately 40% by the end of August.The number of diapause eggs laid by adults of each generation in both the bivoltine and trivoltine populations varies widely. The eggs are deposited on the trunk as well as on the branches, with the heaviest deposition in the central area of the tree. The diapause eggs laid by adults of the first generation are the last to hatch and those laid by the third generation are the first to hatch the following spring.The factors responsible for the differences in the number of generations and in the number of diapause eggs laid are unknown.


2008 ◽  
pp. 3231-3231
Author(s):  
John B. Heppner ◽  
David B. Richman ◽  
Steven E. Naranjo ◽  
Dale Habeck ◽  
Christopher Asaro ◽  
...  
Keyword(s):  

2020 ◽  
Vol 13 (6) ◽  
pp. 2820
Author(s):  
Cristiano Da Silva Rocha ◽  
Fábio Perdigão Vasconcelos ◽  
Delano Nogueira Amaral ◽  
Maria Bonfim Casemiro ◽  
Otávio Augusto de Oliveira Lima Barra

A geografia desempenha um papel importante quando existem trabalhos que tentam relacionar sociedade e natureza, estabelecendo formas (ou variáveis) para qualificar os elementos que compõem a paisagem. Neste trabalho, o objetivo foi aplicar a classificação da vulnerabilidade socioambiental adaptada de Medeiros e Souza (2016), com contribuições de Milanezi e Pereira (2016), como forma de contribuir com a gestão costeira de Paracuru- Ceará. Paracuru é um município costeiro, em que estão presentes diversos ambientes e três Unidades de Conservação Estaduais localizados no rio Curu e nas dunas de Paracuru. Para a análise, sobrepôs-se o mapa de vulnerabilidade ambiental (gerado a partir dos mapas de unidades geoambientais e de uso e ocupação) e de vulnerabilidade social, utilizando 17 variáveis incluídas no cálculo do índice organizados por setores censitários, menor unidade amostral. Foi observado trechos de vulnerabilidade socioambiental alta no setor próximo do rio Curu, na localidade de Santa Rita, com área de interseção de 2,3km² sede urbana localidade denominada de 2,3km² de interseção e setor 16, nas localidades de Muriti, Córrego do Curu e Pedrinhas, com interseção de aproximadamente 800 m². Nas dunas a sobreposição foi predominante de vulnerabilidade ambiental alta e vulnerabilidade social média – alta. Espera-se que as informações possam indicar os ambientes e seções da cidade que são mais suscetíveis e que essas áreas precisam de maior proteção. Socio-environmental vulnerability as a basis for coastal management in the municipality of Paracuru - CearáA B S T R A C TGeography makes an important role when there are works that try to relate society and nature, establishing forms (or variables) to qualify the elements that make up the landscape. In this work, the objective was to apply the classification of socio-environmental vulnerability adapted from Medeiros and Souza (2016), with contributions from Milanezi and Pereira (2016), as a way to contribute to the coastal management of Paracuru-Ceará. Paracuru is a coastal municipality, where there are several environments and three State Conservation Units located on the Curu River and on the Paracuru dunes. For the analysis, the map of environmental vulnerability (generated from the maps of geoenvironmental units and of use and occupation) and social vulnerability was superimposed, using 17 variables included in the calculation of the index organized by census sectors, the smallest sample unit. It was observed stretches of high socio-environmental vulnerability in the sector in the APA of the Curu River, in the locality of Santa Rita, with an intersection area of 2.3 km², in the urban headquarters, places called plateau da barra and secondary carnaubinha 3.1 km² intersection and sector 16, in the localities of Muriti, Córrego do Curu and Pedrinhas, with an intersection of approximately 800 m². In the dunes, the overlap was predominant of high environmental vulnerability and medium - high social vulnerability. It is hoped that the information can serve as a basis for indicating the paths that management should follow to achieve sustainability.Keywords: Landscape, socio-environmental vulnerability, coastal planning.


1964 ◽  
Vol 96 (9) ◽  
pp. 1190-1198 ◽  
Author(s):  
D. G. Harcourt

AbstractVariation between samples of the Colorado potato beetle, Leptinotarsa decemlineata (Say), and between mortalities from some factors, on potato, were determined in long-term study plots at Merivale, Ontario. For each of six age intervals (spring adults; egg masses; larvae, Periods 1 and 2; pupal cells; and summer adults), inter-hill variance was the major source of sampling variance. Intra-hill and block differences were rarely significant. The most appropriate sample unit for the above-ground stages was the potato stalk and for pupal cells, the soil quadrant. Optimum allocation procedures indicated that not more than one sample unit per hill need be taken for the immature stages. For adults, the whole hill should be sampled. To estimate population means with acceptable limits of precision (10% standard error), it is recommended that 50 to 200 hills be sampled for the various age intervals.


1985 ◽  
Vol 117 (4) ◽  
pp. 395-399 ◽  
Author(s):  
Daniel J. Robison ◽  
Lawrence P. Abrahamson ◽  
Miroslaw M. Czapowskyj ◽  
Edwin H. White ◽  
Douglas C. Allen

AbstractOptimum size of a sample unit and within-branch distribution of overwintering spruce budworm were determined for black spruce in northern Maine. No significant differences in sample reliability were found between whole-branch and 45-cm branch-tip samples. Larval distribution on branches varied with total branch length and a model was developed to estimate the whole-branch population from a 45-cm branch tip. Use of a 45-cm branch-tip sample unit is recommended because it is biologically and statistically valid and reduces sampling costs.


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