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| Trenkel, Verena; Skaug, Hans. |
| We propose a random effects model for disentangling population abundance and capture efficiency effects on bottom-trawl catches. The spatial distribution of individual fish is assumed random leading to a Poisson distribution for the number of individuals in the trawl path (no schooling). Capture efficiency, i.e. the proportion of individuals in the trawl path being retained by the gear, is modelled as a random variable. We propose model extensions that include the effects of body size on haul efficiency. We applied the models to several species from the Celtic Sea groundfish community based on small-scale repetitive hauls. The resulting abundance estimates allowed us to study population abundance ratios; the estimated capture efficiencies were comparable... |
| Tipo: Text |
Palavras-chave: Trawl survey; Poisson distribution; Celtic Sea; Catchability; Abundance. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-828.pdf |
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| Nickele,Mariane A; Oliveira,Edilson B de; Reis Filho,Wilson; Iede,Edson T; Ribeiro,Rodrigo D. |
| The spatial distribution of insects is essential to perform control strategies, to improve sample techniques and to estimate economic losses. We aimed to determine the spatial distribution of nests of Acromyrmex crassispinus (Forel) in Pinus taeda plantations. The experiments were carried out in P. taeda plantations with different ages (treatments: recently-planted, three and six-year old plants). The study took place in Rio Negrinho and in Três Barras, SC. Three plots of one hectare were delimited in each treatment, and plots were divided in 64 sample units. The analysis of the dispersion index [variance/mean relationship (I), index of Morisita (Iδ) and k exponent of negative binomial distribution] showed that the majority of the samplings presented... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Leaf-cutting ant; Pinus pest; Poisson distribution; Reforestation. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1519-566X2010000600003 |
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| MALDONADO JR,WALTER; BARBOSA,JOSÉ CARLOS; COSTA,MARÍLIA GREGOLIN; GONÇALVES,PAULO CÉSAR TIBURCIO; SANTOS,TIAGO ROBERTO DOS. |
| ABSTRACT Among the pests of citrus, one of the most important is the red and black flat mite Brevipalpus phoenicis (Geijskes), which transmits the Citrus leprosis virus C (CiLV-C).When a rational pest control plan is adopted, it is important to determine the correct timing for carrying out the control plan. Making this decision demands constant follow-up of the culture through periodic sampling where knowledge about the spatial distribution of the pest is a fundamental part to improve sampling and control decisions. The objective of this work was to study the spatial distribution pattern and build a sequential sampling plan for the pest. The data used were gathered from two blocks of Valencia sweet orange on a farm in São Paulo State, Brazil, by 40... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Red and black flat mite; Negative binomial; Poisson distribution; Decision making; Integrated pest management. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-29452016000400401 |
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| Ribeiro Jr,Paulo Justiniano; Viola,Denise Nunes; Demétrio,Clarice Garcia Borges; Manly,Bryan F.; Fernandes,Odair Aparecido. |
| Onion (Allium cepa) is one of the most cultivated and consumed vegetables in Brazil and its importance is due to the large laborforce involved. One of the main pests that affect this crop is the Onion Thrips (Thrips tabaci), but the spatial distribution of this insect, although important, has not been considered in crop management recommendations, experimental planning or sampling procedures. Our purpose here is to consider statistical tools to detect and model spatial patterns of the occurrence of the onion thrips. In order to characterize the spatial distribution pattern of the Onion Thrips a survey was carried out to record the number of insects in each development phase on onion plant leaves, on different dates and sample locations, in four rural... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Poisson distribution; Spatial statistics; Randomization tests; Geostatistics. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162009000100013 |
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