Three-dimensional variability of soil nitrate-nitrogen in an agricultural field

The aim of this study is to evaluate two different approaches [the layered two-dimensional (2-D) method and a full 3-D approach] to describe the 3-D spatial variability of soil NO₃^--N in the top 1 m of an agricultural field of about 1 ha. NO₃^--N concentrations were determined in layers of 5 cm to a depth of 1 m at 26 locations. These samples were complemented with less intensive sampling at only three depths (0-5, 30-35 and 60-65 cm) at 26 other locations and with topsoil (0-5 cm) samples at another 75 locations. Variogram analysis showed a strong anisotropy when the horizontal dimension was compared to the vertical. A nested model of four structures was used to represent a 3-D variogram. This allowed us to predict the average NO₃^--N concentration for blocks of 5ǹ m (horizontally) by 0.05 m (vertically). A cross-validation showed a clear improvement in using the full 3-D interpolation instead of the layered 2-D approach. The full 3-D interpolation seems to be especially useful in situations where knowledge of the 3-D distribution of soil properties is essential to evaluate soil management practices in respect to environmental considerations, like N fertilisation and the subsequent leaching of N to the ground water, or N₂O emissions.     

The veterinary clinic of Emile Seeldrayers

La "clinique vétérinaire" was created by the Belgian painter Emile Seeldrayers in 1884. The work was purchased by the local administration of Anderlecht in 1893 and given to the Veterinary School of Cureghem in 1961, at the occasion of its 125th anniversary. The painting is nowadays at the campus of Sart Tilman, in the premises of the Faculty of Veterinary Medicine of the University of Liège. According to the tradition it seems to be a key painting: the figures representing professor Lambert Hendrickx and different important persons of Anderlecht. Authorized evidence as well as certain facts refute this hypothesis; even if the realism of the painting is evident, the scene might be imaginary. In 2000 the deputy of Fine Arts of Anderlecht acquired a study of Seeldrayers that proves that the painter was frequently on the premises of the veterinary school, the he was inspired by the places, but that he modified them in order to make his composition more attractive.     

Detection of haemoparasites in cattle by reverse line blot hybridisation with a note on the distribution of ticks in Sicily

A reverse line blot hybridisation (RLB) of 21 oligonucleotides with polymerase chain reaction (PCR) amplified regions of 16S rRNA (Ehrlichia/Anaplasma group) or 18S rRNA (Babesia/Theileria group) genes of haemoparasites detected Theileria annulata, T. buffeli/orientalis, Babesia bovis, B. bigemina, B. divergens, Ehrlichia bovis, Anaplasma marginale, A. centrale and unknown species within the Rickettsia tribe.A very high prevalence of mixed infections was detected, which indicated that animals infected with Babesia spp. were also infected with Theileria spp. and/or Anaplasma spp.The tick distribution appeared to be seasonal with Hyalomma marginatum as the most frequently observed tick and Boophilus annulatus and Ixodes ricinus as the least frequently observed ticks. Other species identified in the 818 ticks collected during the five sampling periods between April 1998 and November 1999 included H. lusitanicum, Rhipicephalus sanguineus group, R. bursa, Dermacentor marginatus, Haemaphysalis punctata, B. annulatus and I. ricinus.     

Effect of alternate distribution of astaxanthin on rainbow trout (Oncorhynchus mykiss) muscle pigmentation

The aim of the present study was to determine the effects of the use of astaxanthin alternate feeding on rainbow trout pigmentation in term of astaxanthin serum concentration, muscle colour and astaxanthin muscle retention. Four hundred and fifty rainbow trout were fed the same basal diet supplemented with two different astaxanthin levels, 100, and 200 mg astaxanthin kg^? 1 of diet, hereafter designated as AX100 and AX200, respectively. An additional astaxanthin-free (AX0) diet was used. The experimental treatments were as follows: (1) REF = AX100 diet at each meal each day, served as reference; (2) SD1 = AX100 diet at each meal the first day followed by AX0 diet at each meal every second day; (3) SD2 = AX100 diet and AX0 diet in alternate meals each day; (4) R2 = AX200 diet and AX0 diet in alternate meals each day; (5) R4 = AX200 diet at the first meal the first day followed by AX0 diet at the second meal the first day and at each meal every second day. Fish were fed the experimental feeding schedule for 42 days.At the end of the experiment there were no significant differences among fish fed the different feeding schedules in term of final mean weight, specific growth rate and feed efficiency ratio. SD2 fish group displayed the highest (P < 0.05) astaxanthin serum concentration and the R4 fish group the lowest one. REF and R2 fish groups showed similar astaxanthin serum concentrations. Muscle chroma showed the most pronounced effect. It increased significantly for all fish groups during the experiment. At the end of the experiment REF and R2 fish groups displayed higher values than SD1 and R4 fish groups. Muscle astaxanthin concentrations increased significantly during the experiment whatever the astaxanthin feeding schedule. At the end of the experiment, the highest muscle astaxanthin concentration was recorded for R2 fish group while the lowest was noted for R4 fish group. Except for SD1 and R4 fish groups, muscle astaxanthin retention decreased significantly during the experiment. At the end of the experiment, muscle astaxanthin retention coefficients for SD2 fish group were significantly higher than those for REF fish group. The results reported here provide further evidence of the potential applicability of alternate astaxanthin feeding on rainbow trout pigmentation. Extending the optimisation of the SD2 treatment will therefore be subject for future studies. Its application could result in cost saving in the fish farming industry.     

Seroprevalence of Rift Valley fever virus in cattle in the Democratic Republic of the Congo

Tropical Animal Health and Production - This study aimed at assessing the serological and virological status of Rift Valley fever virus (RVFV) in cattle from four climatically diverse zones of the...     

Drivers of density for the exploited giant clam Tridacna maxima: a meta‐analysis

Giant clam populations have been over‐exploited throughout their range over the past decades for their meat and shells. Tridacna maxima, commonly known as the ‘small giant clam’, has remained relatively untargeted by fishers in areas where larger species occur (e.g. Tridacna squamosa), and high densities of the species are still observed on some isolated and enclosed reefs of the Central Pacific. However, it is unclear whether reported discrepancies in densities worldwide reflect differences in fishing pressure only or a combination of differences in exploitation levels and environmental forcing. We reviewed T. maxima surveys throughout its range to (i) identify patterns of density at global scale, site scale (e.g. island) and intrasite scale; (ii) discuss the influence of sampling method on density estimates; and (iii) identify the primary drivers of giant clam density along gradients of human pressure and natural forcing. We found 59 studies that reported density estimates for 172 sites across 26 countries in the Indo‐Pacific and Red Sea. At intrasite scale, densities were strongly dependent on sampling protocols and surveyed habitats. At site scale, we found close links between T. maxima density and human population per reef area, suggesting that isolated reefs where exploitation only recently started may be more vulnerable to stock collapse in the future. Density patterns were also found to vary significantly depending on reef type (e.g. atoll, island, continental coastline). We discuss how natural processes and fishing pressure may control population dynamics and densities among sites, and make recommendations for future research.     

Trace Elements in Tephra Soils of Mounts Kupe and Manengouba (Cameroon)

Eurasian Soil Science - Increasing demographic pressure in the area around the Mounts Kupe and Manengouba (Cameroon) is leading to increased agricultural activities with potential heavy metal...