Numerical investigation of the influence of texture,surface drip emitter discharge rate and initial soil moisture condition on wetting pattern size

Knowledge of the dimensions of the wetted zone formed under point source surface drip irrigation is essential to the design of cost-effective and efficient irrigation systems. Numerical simulations were carried out with Hydrus-2D/3D to investigate the influence of emitter discharge rates and initial soil moisture conditions on the wetting pattern dimensions of a series of soils with varying textures. Numerical simulations of simple 2D soil tank irrigation experiments were also conducted on two soil types. Based on the simulation results, the parameters of the Schwartzman and Zur model were refined. The results showed a small influence of discharge rates >1 L h^?1 on the size of the wetting pattern. The only major difference was observed for the rates lower than 0.5 L h^?1, where the largest wetting patterns were observed. Higher initial soil water content caused larger wetting pattern sizes in all directions. When compared to the 2D tank experimental results, Hydrus-2D/3D predicted the wetting pattern dimensions with a relatively small root mean square error not exceeding 2.6 cm. The numerical data obtained for a wide range of textures provided the opportunity to refine the parameters of the Schwartzman and Zur model, which, when compared to experimental data from the literature, provided good estimates of wetting pattern dimensions. This suggests that this simple model, for which the only soil parameter required is the saturated hydraulic conductivity, could provide a valuable and practical tool for irrigation design.     

Gas disks to gas giants: simulating the birth of planetary systems

The ensemble of now more than 250 discovered planetary systems displays a wide range of masses, orbits and, in multiple systems, dynamical interactions. These represent the end point of a complex sequence of events, wherein an entire protostellar disk converts itself into a small number of planetary bodies. Here, we present self-consistent numerical simulations of this process, which produce results in agreement with some of the key trends observed in the properties of the exoplanets. Analogs to our own solar system do not appear to be common, originating from disks near the boundary between barren and (giant) planet-forming.     

RADIOGRAPHIC AND ULTRASONOGRAPHIC FEATURES OF HYPERTROPHIC FELINE MUSCULAR DYSTROPHY IN TWO CATS

Hypertrophic fellne musculer dystrophy has been reported as an X-linked inherited deficiency of a cytoskeletal myofiber protein called dystrophin. This report deserlbes the radiographic and ultrasonographic abnormalities of two male littermate domestic short-hair cats and reviews the previous reported findings assoclated with hypertrophic feline muscular dystrophy. The thoracic radiographic abnormalities included: progressive cardiomegaly, large convex, scalloped irregularities associated with the vetral aspect of the diaphragm, and variable degrees of esophageal dilation (megaesophagus) with associated cranioventral aspiration pneumonia. Echocardiographic features included: concentric left vetricular wall thickening, increased left ventricular and diastolic and systolic dimensions, and an increase in endocardial echogenicity. Abdominal radiographic abnormalities included: hepatosplenomegaly, peritoneal effusion, renomegaly, adrenal gland mineralization, and paralumbar and diaphragmatic musculature enlargement. Abdomlnal ultrasonographic abnormalities included: irregularly thickened muscular portion of the diaphragm; hypoechogenicity of the liver; peritoneal effusion; hepatosplenomegaly; renomegaly with hyperechoic cortex and medulla; and adrenal gland mineralization. The irregular scalloped appearance of the diaphragm (particularly along the ventral/sternal margin) was a consistenl radiographic abnormlity in the two cats with hypertrophic feline muscular dystrophy after the age of 7 months. This finding was confirmed by ultrasound as a thickened irregular, hyperechoic diaphragm. A diagnosis of hypertrophic feline muscular dystrophy should be strongly suspected if this abnormality is identified.     

Growth of Atlantic Salmon,Salmo salar,Fed Diets Containing Barley Protein Concentrate

A 16-week feeding trial was conducted with juvenile Atlantic salmon (123 g/fish initial weight) to determine the effects of adding either 11% or 22% barley protein concentrate (BPC) to the diet compared to salmon fed a reference diet (0% BPC) containing mostly fishmeal. The fish were stocked into twelve 0.264 m³ tanks, providing 40 fish per tank with an average density of 18.55 kg/m³. Temperature was maintained at ?12°C and salinity at ?2 ppt using ground water during the study. There were no significant differences in specific growth rate (0.62 basal, 0.60 11% BPC, 0.72 22% BPC), feed conversion (1.06, 1.37, 1.09), weight gain (124.3 g, 113.5 g, 155.3 g), proximate composition of the salmon for lipid (8.4%, 7.8%, 9.8%), protein (17.3%, 17.1%, 18.6%), moisture (71.4%, 72.3%, 69.4%), and ash (6.5%, 6.1%, 6.9%) among any of the treatment groups. Salmon fed the diet containing 22% barley protein concentrate, however, had significantly greater energy retention (34%) compared to the fish fed the other diets (23%–28%). The results of this study indicate that barley protein concentrate is an acceptable feed ingredient for Atlantic salmon that should provide performance similar to fishmeal at inclusion rates below 22%.     

Environmental effects related to the local absence of exotic fish

Given the extent of biological invasions in industrialized countries, our understanding of the determinants of overall patterns of biological invasions could gain most from consideration of why exotic species are absent from some areas, rather than from distribution patterns of exotic species. Fish communities were sampled at 381 sites representing 221 rivers in the Adour-Garonne stream system (116 000 km², SW France). Very few rivers were not colonized by exotic fish species, however, on a local basis, only 33% of the sampling sites hosted exotics. Using General Linear Modelling, we found that patterns of exotic fish (occurrence, number of species, proportion within assemblage) responded to both land-use and physical variables, whereas patterns of native fish only responded to the local meso-scale characteristics of each stream reach from headwaters to mouth. All fish communities were susceptible to invasion regardless of native species richness, and higher native species richness did not decrease the opportunity for establishment by exotic species. The likelihood that exotic fish are absent primarily increased with elevation and with lower human influence upon the land cover, while human-impacted landscapes (agricultural and urban areas) were more likely to host exotic fish and higher numbers of exotic species. In light of urban and agricultural development, our ability to detect responses of exotic species to landscape alterations using a combination of simple physical and land cover variables exemplifies a cost-effective technique for assessing areas at greater invasion risk in large stream systems.     

Molecular investigation of hard ticks (Acari: Ixodidae) and fleas (Siphonaptera: Pulicidae) as potential vectors of rickettsial and mycoplasmal agents

The aim of the present study was twofold. First, in general, to reveal new aspects of the potential vector role of ixodid ticks and fleas by screening large numbers of specimens with recently developed molecular biological methods. Second, to evaluate the occurrence of vector-borne infectious agents in a geographical context. Altogether 3442 unfed hard ticks (Ixodes ricinus, Dermacentor marginatus, D. reticulatus, Haemaphysalis inermis, H. concinna, H. punctata) and 939 fleas of cats and dogs (Ctenocephalides felis, C. canis, Pulex irritans) were collected in Hungary. DNA was extracted and analyzed in pools for representatives of the orders Rickettsiales and Mycoplasmatales.H. inermis was newly identified as the most important potential vector for Rickettsia helvetica in the study region. A novel Rickettsia genotype (designated ‘Candidatus R. hungarica’) was also detected in the same tick species, with a maximum of 95.8% gltA gene sequence identity to known rickettsiae. In addition, P. irritans tested positive for Rickettsia sp. RF2125, which has not been previously described in Europe. The human pathogen R. felis and the feline pathogen ‘Candidatus Mycoplasma turicensis’ were shown for the first time to occur in Central-Eastern Europe. Further novel findings include the presence of Spiroplasma spp. in D. marginatus and fleas. In conclusion, this molecular study extends the geographic range and vector spectrum of several arthropod-borne agents, some of which have zoonotic potential.     

Ultrasonographic evaluation of the effects of azithromycin on antral motility and gastric emptying in healthy cats

BackgroundErythromycin, a macrolide antibiotic with motilin agonist properties, shortens gastric emptying (GE) time in healthy cats. Azithromycin, another macrolide antibiotic, is effective for treatment of gastric paresis in people.ObjectivesTo evaluate the effects of azithromycin on GE and gastric motility in healthy cats in comparison with erythromycin (positive control) and placebo.AnimalsEight healthy purpose‐bred cats.MethodsProspective, blinded, crossover study. Cats received either azithromycin (3.5 mg/kg PO q24h), erythromycin (1 mg/kg PO q8h), or placebo for 24 hours before and during evaluation of GE. A validated method using ultrasound for sequential measurements of antral area as well as amplitude and frequency of contractions was used to assess GE and evaluate gastric antral motility postprandially over an 8‐hour period.ResultsGE was significantly faster (P < .05) after administration of azithromycin and erythromycin when compared to placebo in the late phase of fractional emptying from 75% (mean ± SD: 327 ± 51 minutes, 327 ± 22 minutes, and 367 ± 29 minutes, respectively), to 95% fractional emptying (399 ± 52 minutes, 404 ± 11 minutes, and 444 ± 24 minutes, respectively). The drugs had no significant effect on antral motility variables at any time point.Conclusions and Clinical ImportanceAzithromycin and erythromycin shorten GE time in a comparable manner in healthy cats. Evaluation of their efficacy in cats with gastric dysmotility is warranted.     

Metabolism of [14C]cymoxanil in grapes,potatoes and tomatoes

Foliar-applied [¹⁴]cymoxanil, 1-(2-cyano-2-methoxyimino-[2-¹⁴C]acetyl)-3-ethylurea was rapidly metabolised in grapes, tomatoes and potatoes, Furthermore, the metabolism of this fungicide was unusual in that the metabolites were found to be naturally occurring compounds, with glycine as the major metabolite. Significant levels of radioactivity were found in other amino-acids, sugars, starch, fatty acids and lignin, indicating incorporation of carbon-14 via the various metabolic pathways.