Consulta: subjectFacets:"Sampling strategy"
Registros recuperados: 7
Data/hora: 06/06/2024 13:54:04

Towards an optimal sampling strategy for assessing genetic variation within and among white clover (Trifolium repens L.) cultivars using AFLP
Provedor de dados: 74
Autores: Khanlou,Khosro Mehdi; Vandepitte,Katrien; Asl,Leila Kheibarshekan; Bockstaele,Erik Van.
Cost reduction in plant breeding and conservation programs depends largely on correctly defining the minimal sample size required for the trustworthy assessment of intra- and inter-cultivar genetic variation. White clover, an important pasture legume, was chosen for studying this aspect. In clonal plants, such as the aforementioned, an appropriate sampling scheme eliminates the redundant analysis of identical genotypes. The aim was to define an optimal sampling strategy, i.e., the minimum sample size and appropriate sampling scheme for white clover cultivars, by using AFLP data (283 loci) from three popular types. A grid-based sampling scheme, with an interplant distance of at least 40 cm, was sufficient to avoid any excess in replicates. Simulations...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Sampling strategy; White clover; AFLP; Genetic diversity parameters.
Ano: 2011
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572011000200015

Genetic structure at different spatial scales in the pearl oyster (Pinctada margaritifera cumingii) in French Polynesian lagoons: beware of sampling strategy and genetic patchiness
Provedor de dados: 5
Autores: Arnaud, Sophie; Vonau, Vincent; Rouxel, Catherine; Bonhomme, Francois; Prou, Jean; Goyard, Emmanuel; Boudry, Pierre.
In order to study further the genetic structure of the pearl oyster Pinctada margaritifera in French Polynesia with a special consideration for the sampling scale, we analyzed or re-analyzed sets of data based on nuclear DNA markers obtained at different spatial scales. At a large scale (several 1,000 km), the remote Marquesas Islands were confirmed to be significantly differentiated from Tuamotu-Gambier and Society archipelagos, with a marked difference however for the two main islands that are different from each other. At a medium scale (several 10 to several 100 km), overall homogeneity was observed within and between these two archipelagos, with some exceptions. This could be attributed both to large-scale larval dispersal and to human-driven spat...
Tipo: Text
Palavras-chave: Population genetics; Polynesia; Bivalve; Pearl oyster; Benthic organisms; Sampling strategy; Genetic patchiness.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-4960.pdf

Mortalité et croissance de l'huître creuse C. gigas dans le bassin de Marennes Oléron. Résultats obtenus sur le site atelier de Ronce-Perquis en 1997-1999
Provedor de dados: 5
Autores: Soletchnik, Patrick; Le Moine, Olivier; Faury, Nicole; Razet, Daniel; Geairon, Philippe; Robert, Stephane; Goulletquer, Philippe; Taillade, Sylvie.
The 1999 monitoring of the C. gigas mortality rates showed a 32 to 40% loss for the on-bottom rearings located on the Ronce-Perquis oyster bank. In 1997, the averaged mortality rate varied between 23 and 29% without significant site effect. These mortality rates were ranging from 17 to 32% in 1998 with significant limited mortality rate on site 4 (17%). However, those rates were underestimated by 7 to 8%, based on our 1999 study, Actually, the spatial distribution for these rates on 2 experimental sites divided into 25 subunits demonstrated a large variability ranging from 17-37% and 22-56% for sites 1 and 2, respectively. In spite this large variability, the mortality rates results were larger on the muddy bottom site. In contrast to site 1, the oysters...
Tipo: Text
Palavras-chave: Bay of Marennes Oleron; Crassostrea gigas; Reproductive effort; Biochemical composition; Growth; Sampling strategy; Mortality rates; Bassin de Marennes Oléron; Crassostrea gigas; Effort de reproduction; Composition biochimique; Croissance; Méthodologie d'estimation; Taux de mortalité.
Ano: 2000
URL: http://archimer.ifremer.fr/doc/2000/rapport-1641.pdf

Comparison of surfaces
Provedor de dados: 5
Autores: Legendre, P; Mcardle, Bh.
Values of a variable observed over a delimited geographic area are called a ''surface''. The problem we investigate is how to compare measures of the same area observed at two or more Sampling times. It is important to recognise that two different null hypotheses can be tested about the surface. The first is that the corresponding values in the surfaces differ only because of measurement or sampling error. The second is that the underlying process that generated the surfaces is the same. In the first case, the surfaces should have the same shape and values, while in the second case the surfaces might have different values, but if they still have the same means, variances and autocorrelation structures, the null hypothesis cannot be rejected. To prove the...
Tipo: Text
Palavras-chave: Analysis of variance; Comparison of surfaces; Log-linear model; Sampling strategy; Trend surface analysis.
Ano: 1997
URL: http://archimer.ifremer.fr/doc/00093/20397/18064.pdf

Heterogeneity of sediments and settling particles in aerated ponds
Provedor de dados: 5
Autores: Kassila, Jawad; Hussenot, Jerome.
A study was conducted in seabass (Dicentrarchus labrax) and oyster (Crassostrea gigas) ponds to assess the levels of heterogeneity of sediments and settling particles. The intensity of sampling to estimate with high accuracy some characteristics will depend on the magnitude of the variation within the population under consideration. Several variables, such as total phosphate (Tot-P), total iron (Tot-Fe), total ammonium nitrogen (TAN), organic carbon (Org-C), total nitrogen (Tot-N) and P fractions were analysed during the rearing period. The box-and-whisker plots were used as graphical/statistical tools to visualize the descriptive statistical characteristics of the data. In the fish pond, the sediments have high concentrations of Tot-P, Tot-Fe and TAN in...
Tipo: Text
Palavras-chave: Sampling strategy; Resuspension; Sedimentation; Artificial aeration; Particles; Sediment.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/publication-1224.pdf

Design and application of a stratified sampling strategy to study the regional distribution of cyanobacteria (Ile-de-France, France)
Provedor de dados: 5
Autores: Catherine, A; Troussellier, Marc; Bernard, C.
This study describes the design and application of a stratified sampling strategy of waterbodies to assess and analyze the distribution of cyanobacteria at a regional scale (Ile-de-France, IDF). Ten groups of hydrographical zones were defined within the IDF on the basis of their anthropogenic and geomorphologic characteristics. Sampling effort (n = 50) was then randomly allocated according to the number of waterbodies in each group. This sampling strategy was tested in August 2006, using a field probe to estimate total phyto-plankton as well as cyanobacteria biomasses. The sampled waterbodies exhibited a wide range of phytoplankton (&lt;1-375 mu g equiv.Chla L-1) and cyanobacteria biomasses (&lt;1-278 mu g equiv. Chla L-1). 72% of the waterbodies in the...
Tipo: Text
Palavras-chave: Sampling strategy; Land use; Lakes and reservoirs; Geographic information system; Cyanobacteria.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-5302.pdf

Conservation of Forest Biodiversity: how sample size affects the estimation of genetic parameters
Provedor de dados: 42
Autores: Costa,Leonardo S. da; Corneleo,Nathana S.; Stefenon,Valdir M.
Efficient designs are crucial for population genetic studies on forest species. In this study we employed individual based simulations aiming to evaluate what fraction of a population should be sampled to obtain confident estimations of allelic richness and of inbreeding coefficient in population genetic surveys. The simulations suggest that at least 10% of the total population has to be sampled to ensure reliable estimations of allelic richness and inbreeding coefficient. This approach will allow the confidence of the genetic parameters estimations of a larger number of populations, based on a minimal sample within each one.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Sampling strategy; Study design; Allelic richness; Inbreeding coefficient.
Ano: 2015
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652015000201095