An heuristic algorithm for short term irrigation scheduling using hosereel-raingun systems

Growers who irrigate need to answer three questions throughout the growing season — (i) when should each field be irrigated; (ii) how much water should be applied; and (iii) which field should be irrigated first. An heuristic solution procedure has been developed to produce realistic irrigation schedules, within a practical time, for growers using hosereel-raingun irrigators. The financial implications of the irrigation schedules are analysed over a short term period (typically 7 days). The constraints are limited availability of equipment, labour and/or water. Use of the model is illustrated with a common situation faced by a U.K. grower.     

European reference method for the in vivo determination of metabolisable energy with adult cockerels: reproducibility, effect of food intake and comparison with individual laboratory methods

1. A common reference procedure adopted by several European laboratories to determine apparent metabolisable energy corrected to zero-nitrogen balance (AMEn) is described. 2. Reproducibility has been estimated by comparing results from 4 diets measured in 7 laboratories. The standard deviations between laboratories of dry matter, gross energy, Kjeldahl nitrogen and AMEn were respectively, on average, 11.29 g/kg, 0.242 MJ/kg, 1.56 g/kg and 0.380 MJ/kg dry matter; the corresponding coefficients of variation between laboratories were 1.27, 1.29, 4.39 and 2.92%. 3. Effect of food intake was tested by comparing AMEn from birds fed either 0.90 or 0.45 of ad libitum: the amount of food intake had a negligible effect on AMEn values. Endogenous energy losses corrected (EELn) or not (EEL) to zero nitrogen balance were estimated either by regression between excreted energy and ingested energy or in fasted and glucose-fed cockerels. EELn estimated by regression was, on average, 8.7 kJ/bird/d.; it was independent of diet composition. EEL and EELn determined in fasted or glucose-fed birds were higher than those determined by regression. 4. AMEn values measured by individual laboratory procedures were very close to those obtained by the reference method, except from laboratories using a tube feeding procedure, where deviations were probably a consequence of overestimated EEL.     

Masking of two in vitro immunological assays for Mycobacterium bovis (BCG) in calves acutely infected with non-cytopathic bovine viral diarrhoea virus.

Acute infection of calves, previously vaccinated with bacille Calmette-Guerin (BCG), with non-cytopathic viral diarrhoea virus (BVDV) resulted in the temporary suppression of two in vitro assays used to monitor Mycobacterium bovis infection. Lymphocyte proliferation and interferon-gamma production by whole blood cultures containing purified protein derivatives prepared from Mycobacterium avium (PPD-A) and M bovis (PPD-B) were markedly suppressed. The implication is that acute infections of cattle with non-cytopathic BVDV may temporarily compromise diagnostic tests for M. bovis infections and result in a failure to identify cattle with tuberculosis.     

Evaluating genetic relationships in seed impatiens, Impatiens walleriana, using AFLP profiling

Although seed impatiens is the leading bedding plant in the US, little work has been conducted on evaluating the genetic variability present in this crop. In this study, amplified fragment length polymorphism technology was utilized to determine the level of polymorphism present across 20 commercial cultivars of seed impatiens, to assess their genetic variability, and to investigate their genetic relatedness. A total of eight EcoRI and MseI primer combinations were used for polymerase chain reaction amplification. Fluorescence‐labelled amplification products were subjected to electrophoresis and then analysed using an automated sequencer. High levels of polymorphism were detected among all 20 cultivars for all primer combinations tested. Gower's Genetic Dissimilarity estimates for the entire set of cultivars ranged from 1.000 to 0.316. The dendogram generated from these dissimilarity data revealed a number of groupings, including one major division which placed all of the cultivars into one of two groups. The implications of these results on genetic variability, genotypic relationships and genetic diversity in seed impatiens is discussed.     

The uveodermatologic syndrome in dogs]

A review of the literature pertaining to the uveodermatological syndrome of dogs is presented. This syndrome is marked by depigmentation of the periocular region, lips and nose in association with severe uveitis. Early diagnosis and therapy can prevent serious vision loss. Symptoms and therapy of the cases described in the literature as well as cases seen at the Veterinary Medical Teaching Hospital in Davis/California are discussed.     

European reference method of in vivo determination of metabolisable energy in poultry: reproducibility, effect of age, comparison with predicted values

1. Apparent metabolisable energy corrected to zero-nitrogen retention (AMEn) was measured using the European reference procedure in 9 European laboratories. Seven pelleted diets were evaluated. AMEn was measured with adult cockerels and young birds. 2. Between-laboratory standard deviations were for dry matter (DM) 12.5 g/kg, gross energy 0.085 MJ/kg DM, Kjeldahl nitrogen 0.768 g/kg DM, AMEn (adults) 0.256 MJ/kg DM, and AMEn (young) 0.337 MJ/kg DM. Corresponding coefficients of variation between laboratories were 1.42, 0.45, 2.15, 1.88 and 2.60% respectively. 3. AMEn values of experimental diets were always significantly lower when measured with young birds. This effect was more pronounced when diets contained added fat. 4. Tallow or soyabean oil were incorporated into two basal diets at 40 g/kg inclusion rate. No significant differences were observed between AMEn values of either diet with adults or young birds, suggesting that AMEn energy values of these fats are indistinguishable at this inclusion rate. 5. Similar AMEn values were obtained in young birds by estimating nitrogen accretion, either by the difference between intake and excreta nitrogen or by measuring body weight gain. Determined AMEn values were very similar to those predicted using three different regression equations.     

Stratigraphic sections, bedding sequences, and random processes

Both dependent and independent random processes can be used to study and synthesize stratigraphic sections and bedding sequences. Synthetic stratigraphic sections can be modeled to fit any geologic problem with a good correspondence between the synthetic and actual stratigraphic sections. To synthesize a sedimentary sequence, one needs only a transition procedure to go from one lithology or bedding type to another, and frequency distributions of thickness for the various lithologies. A sedimentation process with a "memory" is termed Markovian; if the past has no influence on either present or future sedimentation, it is called an independent trials process.     

Terrestrial habitat requirements of nesting freshwater turtles

Because particular life history traits affect species vulnerability to development pressures, cross-species summaries of life history traits are useful for generating management guidelines. Conservation of aquatic turtles, many members of which are regionally or globally imperiled, requires knowing the extent of upland habitat used for nesting. Therefore, we compiled distances that nests and gravid females had been observed from wetlands. Based on records of > 8000 nests and gravid female records compiled for 31 species in the United States and Canada, the distances that encompass 95% of nests vary dramatically among genera and populations, from just 8 m for Malaclemys to nearly 1400 m for Trachemys. Widths of core areas to encompass varying fractions of nesting populations (based on mean maxima across all genera) were estimated as: 50% coverage = 93 m, 75% = 154 m, 90% = 198 m, 95% = 232 m, 100% = 942 m. Approximately 6–98 m is required to encompass each consecutive 10% segment of a nesting population up to 90% coverage; thereafter, ca. 424 m is required to encompass the remaining 10%. Many genera require modest terrestrial areas (<200 m zones) for 95% nest coverage (Actinemys, Apalone, Chelydra, Chrysemys, Clemmys, Glyptemys, Graptemys, Macrochelys, Malaclemys, Pseudemys, Sternotherus), whereas other genera require larger zones (Deirochelys, Emydoidea, Kinosternon, Trachemys). Our results represent planning targets for conserving sufficient areas of uplands around wetlands to ensure protection of turtle nesting sites, migrating adult female turtles, and dispersing turtle hatchlings.