From marl to rock powder: On the history of soil fertility management by rock materials

The ancient practice of marling and the recent application of rock powder to soils are interventions into the orogenic energy budget of soils. Both are slow‐release, long‐term fertilizers or better, soil conditioners. Marls and their uses are reviewed by a study of knowledge and practices from the 1st century AD to the 1800s, for rock powders, a review of the recent theoretical and experimental literature is presented. Under pre‐industrial conditions, paucity of energy prevented the wide‐spread use of such materials, today they are marketed as by‐product of industrial operations. For marls and rock powders alike, their positive effect depends to a large extent on the soil matrix to which the minerals are applied, on the cultivar, and the specific type of applied material. Drawing parallels between the two materials, we suggest that the long‐term experience with marls could be used to study the effects of rock powders, as duration of experiments with these is most often too limited to allow conclusions.     

Cluster analysis of linear model coefficients under contiguity constraints for identifying spatial and temporal fishing effort patterns

For fisheries management purposes, it is essential to take into account spatial and seasonal characteristics of fishing activities to allow a reliable assessment of fishing impact on resource. This paper presents a novel technique for describing spatial and temporal patterns in fishing effort. The spatial and seasonal fishing activity patterns of the French trawler fleet in the Celtic Sea during the period 1991–1998 were analysed by modelling fishing effort (fishing time) with generalised linear models. The linear model for fishing effort included fixed effects for both spatial (statistical rectangles) and temporal units (months). In addition, spatial correlations in any given month were modelled by an exponentially decreasing function. Temporal correlations were included using the previous month's fishing effort for a given spatial unit as predictor. A method based on cluster analysis of estimated model coefficients of spatial or temporal fixed effects is proposed for identifying groups of similar spatial and temporal units. A contiguity constraint is imposed in the clustering algorithm, ensuring that only neighbouring spatial units or consecutive temporal units are grouped. The cluster analysis identified 22 spatial and 9 temporal groups. Winter and spring months stood out as being more variable than the remaining months. Spatial groups were of varying size, and generally larger offshore. The proposed method is generic and could for example be used to analyse temporal and spatial patterns in catch or catch rate data.     

Pemphigus foliaceus in the horse: a retrospective study of 20 cases

Twenty horses with pemphigus foliaceus were seen over a period of 15 years in a veterinary medical teaching hospital. Breeds seen were seven quarterhorses, five thoroughbreds, three cross-bred horses, two Arabians and one of each of the following: standardbred, Tennessee walker and warmblood. There was no breed, age or sex predisposition. Nine were mares, ten were geldings and one was a stallion. Ages ranged from 2.5 months to 25 years, with a mean of 8.6 years. Sixteen (80%) of the pemphigus foliaceus horses first exhibited signs between September and February. There was a statistically significant more common occurrence of pemphigus foliaceus during those months. Signs in the four other horses were first noted in March, May or June. Three of those horses were < 13 months of age. Oedema (14/20) and crusts (13/20) were the most common lesions. Pain was present in 9/20 horses, pruritus in 7/20 and pyrexia in 7/20. Follow-up was available for 13 horses. Five of these horses were euthanased. In three horses the reason for euthanasia was laminitis secondary to treatment. Four horses remained lesion-free after medication was discontinued. Two horses required maintenance medication and are doing well at the time of writing.     

Genetic and phenotypic trends in canine hip dysplasia in the German population of German shepherd dogs

Phenotypic and genetic trends were examined in 157,455 German shepherd dogs of the German population born between 1985 and 2003 which were Xrayed for canine hip dysplasia (CHD). A subset of 40,270 dogs born between 1998 and 2003 was examined for which information was available on age at examination and X-raying veterinary practitioner. Relative breeding values were predicted using best linear unbiased prediction methods (BLUP) and Gibbs Sampling. There was an almost linear and significant decline in both phenotypic and genetic trends for CHD scores (scale 1 to 5 for CHD free to severe CHD) over a period of 19 years, with b = -0.021 +/- 0.002, and b = -1.69 +/- 0.05, respectively. After introduction in 1999 of a selection scheme based on relative breeding values (RBVs, mean 100, standard deviation 20) of a linear animal model, phenotypic and genetic trends declined less than before 1999, with b = -0.019 +/- 0.011 and b = -1.43 +/- 0.29. Analysis of the effects of RBVs of parental combinations among sires and dams on the percentage of non-affected progeny showed that lower RBVs were associated with a higher percentage of non-affected progeny than were higher RBVs. In addition, it was also shown that selection procedures based on RBVs are more efficient than selection schemes based on phenotypic records of parents. When the maternal RBV was above 100, the proportion of non-affected progeny was between 10% and 20% lower than when the maternal RBV was below or equal to 100. There was a significant relationship between higher inbreeding coefficients and higher RBVs of the animal.     

A centrosome-independent role for gamma-TuRC proteins in the spindle assembly checkpoint

The spindle assembly checkpoint guards the fidelity of chromosome segregation. It requires the close cooperation of cell cycle regulatory proteins and cytoskeletal elements to sense spindle integrity. The role of the centrosome, the organizing center of the microtubule cytoskeleton, in the spindle checkpoint is unclear. We found that the molecular requirements for a functional spindle checkpoint included components of the large gamma-tubulin ring complex (gamma-TuRC). However, their localization at the centrosome and centrosome integrity were not essential for this function. Thus, the spindle checkpoint can be activated at the level of microtubule nucleation.     

Can native tree species plantations in Panama compete with Teak plantations? An economic estimation

Panama has the highest rate of change in the area of primary forests within Central America. However, to meet growing timber demands, it became popular over the last decades to establish plantations made up of foreign species such as Tectona grandis or Pinus spp. In the majority of the cases the species used are well known; their characteristics such as growth performance have been reviewed intensively and can be accessed in numerous publications. Characteristics of Panama’s native tree species of commercial relevance such as Hieronyma alchorneoides, Swietenia macrophylla and Terminalia amazonia are largely unknown and have been investigated within the study at hand. Using valuation methods of financial mathematics, the competitive position of these three indigenous species was assessed, the results compared to those of T. grandis stands in the same area. Land costs and taxes were not considered, as they would be the same for all species. Financial estimates for indigenous species will enlarge their acceptance for use in reforestation and plantation projects. Using the NPV method and applying the standard scenario, the profitability of T. grandis is lower than that of T. amazonia and S. macrophylla and lies only slightly above the profitability calculated for H. alchorneoides. This result clearly indicates that the investigated native tree species are comparable with T. grandis regarding their economic profitability. Besides its ecological impact, growing native tree species is now also economically legitimate. By calculating land expectation values for all tree species, ideal rotation lengths could be determined. For these species, considerable flexibility exists regarding the optimal rotation length.     

RNA and protein synthesis is required for Ancylostoma caninum larval activation

The developmentally arrested infective larva of hookworms encounters a host-specific signal during invasion that initiates the resumption of suspended developmental pathways. The resumption of development during infection is analogous to recovery from the facultative arrested dauer stage in the free-living nematode Caenorhabditis elegans. Infective larvae of the canine hookworm Ancylostoma caninum resume feeding and secrete molecules important for infection when exposed to a host mimicking signal in vitro. This activation process is a model for the initial steps of the infective process. Dauer recovery requires protein synthesis, but not RNA synthesis in C. elegans. To determine the role of RNA and protein synthesis in hookworm infection, inhibitors of RNA and protein synthesis were tested for their effect on feeding and secretion by A. caninum infective larvae. The RNA synthesis inhibitors α-amanitin and actinomycin D inhibit feeding dose-dependently, with IC(50) values of 30 and 8 μM, respectively. The protein synthesis inhibitors puromycin (IC(50)=110 μM), cycloheximide (IC(50)=50 μM), and anisomycin (IC(50)=200 μM) also displayed dose-dependent inhibition of larval feeding. Significant inhibition of feeding by α-amanitin and anisomycin occurred when the inhibitors were added before 12h of the activation process, but not if the inhibitors were added after 12h. None of the RNA or protein synthesis inhibitors prevented secretion of the activation-associated protein ASP-1, despite nearly complete inhibition of feeding. The results indicate that unlike dauer recovery in C. elegans, de novo gene expression is required for hookworm larval activation, and the critical genes are expressed within 12h of exposure to activating stimuli. However, secretion of infection-associated proteins is independent of gene expression, indicating that the proteins are pre-synthesized and stored for rapid release during the initial stages of infection. The genes that are inhibited represent a subset of those required for the transition to parasitism, and therefore represent interesting targets for further investigation. Furthermore, while dauer recovery provides a useful model for hookworm infection, the differences identified here highlight the importance of exercising caution before making generalizations about parasitic nematodes based on C. elegans biology.