Outlier identification of soil phosphorus and its implication for spatial structure modeling

Outliers are classified as global outliers and spatial outliers. Up to now, there is little information about the outliers especially the spatial outliers and their influence on the spatial structure modeling of soil properties. A total of 537 soil samples were collected based on a 30 × 30 m grid in a permanent dairy farm in southeast Ireland. Graphic methods of histogram and box plot combined with Moran’s I were applied to detect the outliers of soil phosphorus (P). Sixteen outliers (5 global outliers and 11 spatial outliers) of soil P were found in the study area. Compared to the raw data, the data with global outliers excluded always had the larger global Moran’s I value indicating a stronger spatial autocorrelation. Clear spatial clusters (High–High and Low–Low clusters) were observed based on local Moran’s I. The High–High spatial clusters were located around the main farm yard and near the traffic route due to more intensive management by farmers. The Low–Low spatial clusters were mainly close to the river. For these areas, P fertilizer or slurry should be applied for healthy grass growth. The dataset with outliers excluded had a reliable semi-variogram model with a low nugget/sill ratio (32.4 %), which was closed to its corresponding transformed data (30.5 %). The cross-validation results revealed that the dataset without outliers had the strongest linear regression model (r = 0.768), indicating that the outliers played an important role in the spatial structure modeling.     

Adaptation de la teneur en enzymes digestives de l'hepatopancreas de Palaemon serratus (Crustacea,Decapoda), a la composition d'aliments experimentaux

The effects of the carbohydrate and protein composition of compound diets on growth rate and on the amylase and protease content of the hepatopancreas have been studied in Palaemon serratus.The best growth rate for animals weighing between 80 and 380 mg is obtained with a diet containing 3.5% carbohydrate and 64% protein. Diets which are very rich in carbohydrate and poor in protein result in poor growth and high mortality; the same is true for foods containing a high concentration of only one protein.Variations in the wet weight of the hepatopanereas and in the total digestive enzymatic activities are linked to variations in the growth rate of the shrimp.Maximal specific amylase activity is reached when assimilable carbohydrate amounts to 2.8%. Maximal specific protease activity is reached when the food protein level reaches 45%. When the amounts of carbohydrate and protein are higher or lower, the values of specific enzymatic proteins diminish.     

Synthesis,conformational studies and anthelmintic activity of a constrained PF1022A analogue

A mono-proline analogue of the potent anthelmintic cyclooctadepsipeptide PF1022A has been synthesized. NMR studies in combination with molecular dynamics simulations demonstrate that the confirmation of this analogue is both rigidified and distorted compared with the asymmetric conformation of PF1022A. The backbone conformation is significant with respect to anthelmintic activity. © 1999 Society of Chemical Industry     

Variation of soil P and other nutrients in a long-term grazed grassland P experiment field

Field-scale variation of soil phosphorus (P) information is very important for P fertilizer application and its soil sampling design in grassland. A total of 108 soil samples were collected from a long-term (41 years) grazed grassland P experiment field at Teagasc, Johnstown Castle, Wexford, Ireland, in March 2009. There were six P treatments (P0-0, P0-30, P15-15, P15-5, P30-30, and P30-0) since 1968, with changes since 1999. Each treatment had 6 replicate plots (a total of 36 plots, 3 soil samples per plot). The samples were analyzed for available (Morgan’s) P, potassium (K), magnesium (Mg), lime requirement (LR), and pH. The highest mean available P concentration was found in the P30-30 (30 kg P ha^?1 pre- and post-1998) plots, and the lowest mean available P concentration was found in the P0-0 (no P fertilizer since 1968) plots. Significant differences of mean P, Mg, LR, and pH values in different treatments were observed. There was a positive proportional effect for both the 36 plots and the 6 treatments for the P data: the local standard deviation increased with the increase of local mean. The proportional effect should be considered in order to optimize sampling design. Fewer samples can reflect soil P status in fields with low soil P levels, while more attention should be paid to the fields with high P levels in order to reduce environmental consequences of uniform applications.