Water distribution pattern in treated wastewater irrigated soils: hydrophobicity effect

The shortage of fresh water (FW) in Israel and other semiarid regions has forced farmers to significantly expand the use of treated wastewater (TWW). Recently, farmers utilizing reclaimed wastewater (TWW) reported a unique type of water distribution regime in drip-irrigated soils, as follows: (i) limited wetted area on the soil surface; and (ii) small saturated areas around and below the dripper, in TWW irrigated soil as opposed to an even, onion-like wet profile, formed under fresh water (FW) irrigation. Following this observation in the field and after conducting preliminary tests in the laboratory, we hypothesized that TWW irrigation introduces water-repellent organic constituents into the soil. Tests characterizing the water distribution showed the diameter of the saturated area on the soil surface and its water content (at a depth of 0–10 cm) was smaller with TWW than with FW irrigation. The TWW accumulated on the soil surface in small lenses and then flowed rapidly into the ground. The repellency of soils irrigated with FW and TWW was measured with the water drop penetration time test. Soils irrigated with FW were hydrophilic, whereas those irrigated with TWW exhibited hydrophobicity. Fourier transform infra-red spectroscopy (FTIR) and ¹³C-NMR analyses of organic components extracted from the soils with organic solvents indicated differences in composition only at a depth of 0–2 cm. Extracting soils with a methanol + chloroform (1:1, by volume) mixture was found to be very effective in the removal and extraction of hydrophobic aliphatic components from soils irrigated with TWW.     

Action of bioresmethrin on the corpus cardiacum of Locusta migratoria

The action of the pyrethroid insecticide bioresmethrin on the corpus cardiacum (CC) has been studied in Locusta migratoria. Bioresmethrin increased the spontaneous electrical activity recorded from both the glandular and storage lobes, and induced repetitive discharge in these lobes in response to single electrical stimulation of the nervus corpus cardiacum II (NCC II) and NCC I, respectively. Incubation of the isolated CC in low concentrations of bioresmethrin (0.1-1.0 μmol) induced the release of bioassayable hyperlipaemic hormone. Injection of bioresmethrin into locusts was found to induce an elevation in the haemolymph lipid at a stage when there was no overt symptom of poisoning. It is concluded that bioresmethrin may act directly on the CC of locusts to modulate electrical activity and induce the release of hormones. The effects may precede overt symptoms of poisoning.     

Mist propagation of peach and almond × peach hybrids

Several factors contributing to the successful rooting of stem cuttings of four peach clones and one almond × peach hybrid under intermittent mist were tested. With the almond × peach cross, leaf-bud cuttings were also tested.Severe cutting back of adult peach mother trees in winter favoured rooting of the cuttings, but less severe cutting back induced maximum roots per cutting.For short periods vermiculite was found to be a suitable medium. Sand alone or mixed with vermiculite or gravel gave poor results. Gravel alone or mixed with vermiculite was intermediate. For growing the rooted cuttings for a longer period, a mixture of perlite and peat was very suitable.A period of illumination of 3 h starting at midnight with incandescent light improved rooting of peach cuttings in August and October, but not in June.With cuttings obtained from old fruit-bearing peach trees highest rooting rates were obtained in July, but best root development occurred when rooting was carried out in October. In July rooting rate of basal cuttings was much higher than that of terminal ones. Success with leaf-bud cuttings (including a small branch piece) obtained from young mother trees of the almond × peach hybrid was only achieved at the end of May or in June.Dipping the base of peach cuttings in water before rooting was of advantage with one cultivar rooted in September, but of no advantage with another cultivar rooted in June.When the base of stem cuttings was dipped for a prolonged period in IBA solutions of various concentrations, highest rooting rates were obtained with 25–50 ppm IBA for peaches and with 200 ppm for the almond × peach hybrid. The addition of Phygon XL to this solution was of some advantage for peach cuttings. The concentration inducing maximum root development was higher than that required for maximum rooting and callusing. The optimal IBA concentration for rooting of almond × peach leaf-bud cuttings was 100 ppm.Penetration of the IBA into the leaf-bud cuttings reached a maximum 45 min a after floating them on a 100 ppm solution.Transplanting cuttings which had been rooted under mist was somewhat difficult; however, high rates of survival were obtained with cuttings planted in September which had developed a good root system.     

Seroprevalence of coxiellosis in cattle, sheep and people in the east of Turkey

Serum samples collected randomly from 416 cattle in 48 herds, and 411 sheep in 47 flocks, in eight different locations in the east of Turkey between June and December 1998, were examined by indirect fluorescent antibody test (IFAT) to determine the prevalence of Q fever. The age, sex, breed, tick control and abortion history of the animals were also recorded. In addition, 102 serum samples were collected from apparently healthy people who were at risk of contracting the disease, such as farmers, veterinarians, abattoir and laboratory workers, and veterinary students. Seropositivity was observed in 5-8 per cent (24/416) of the cattle in 17 (35-4 per cent) of the herds and in 10-5 per cent (43/411) of the sheep in 21 (44-7 per cent) of the flocks. Eight of the 102 people were seropositive, with the highest prevalence (12-0 per cent) in farmers and abattoir workers. All the seropositive farmers had seropositive animals. None of the laboratory workers or veterinary students was seropositive.     

Myotoxic and neurotoxic activity of Bacillus thuringiensis var. israelensis crystal toxin

The mechanism of the entomocidal action of Bacillus thuringiensis var. israelensis (BTI) in Periplaneta americana has been studied. Cockroaches treated with the alkali-solubilized BTI crystal gradually became sluggish and immobile. A physiological examination of poisoned cockroaches indicated that BTI possessed both myotoxic and neurotoxic activity. Following hemocoel or foregut administration of BTI, myotoxic effects were observed within 10–20 min whereas the onset of neurotoxic effects was considerably delayed. The results of this study suggest that the myotoxic action of BTI is probably important for the initial manifestation of its toxicity. The neurotoxic effects of BTI were ascribed to its ability to interfere with transmitter release. BTI exerted a dual action on transmitter release in the cockroach sixth abdominal ganglion. At lower doses (2–4 μg/ml) BTI was found to suppress transmitter release by interfering with calcium uptake. At higher concentrations (12 μg/ml or higher), however, BTI caused blockage of synaptic transmission which was preceded by massive transmitter release. In either case, the synapse blocking action of BTI was probably due to its effects upon presynaptic terminals. Postsynaptic membranes and axons in the ventral nerve cord apparently remained unaffected.     

Effects of cadmium on erythrocytic parameters

Cadmium was administered via the drinking water to rats at doses of 20 and 200 ppm for 5 weeks in order to elucidate cadmium's primary effect on the erythrocytic parameters. From the results, it appeared that the microcytic hypochromic anemia resulted from a direct effect on erythrocytic hemoglobin due to cadmium administration. It was proposed that the adverse effects on hemoglobin absorption and metabolism play a role in the development of the anemia observed.     

The effect of three carotenoid sources on growth and pigmentation of juvenile freshwater crayfish Cherax quadricarinatus

The effect of adding carotenoids from various sources to feed of juvenile freshwater crayfish Cherax quadricarinatus on pigmentation, growth and survival was examined under laboratory conditions. Juvenile crayfish were fed diets fortified with carotenoids at a level of 100 μg g⁻¹ for a period of either 49 or 55 days. Carotenoid sources were: dried algal cells prepared from Dunaliella salina in which the main carotenoid is β-carotene; a synthetic carotenoid, astaxanthin (Carophyll Pink 8%, manufactured by Hoffman–La Roche) and alfalfa meal. Crayfish receiving feeds fortified with carotenoids exhibited better body colouration than those in the control group, which were fed a diet to which no carotenoids were added. Growth and survival of the crayfish were not affected by the addition of carotenoids to their diet.     

Universality of a surface tension—contact‐angle relation for hydrophobic soils of different texture

Wettability of soil affects a wide variety of processes in soils like infiltration, percolation, preferential flow, and surface runoff. Even though efforts have been made to determine contact angles and surface tension or energy of smooth surfaces, the determination on granular materials like soil particles remains unsolved. One objective of this study was to test the consistency of contact angles (CA) measured with the newly modified and easy‐to‐apply Wilhelmy plate method by using solid particles and liquids with defined variations of surface tension. A second objective was to derive basic physical surface properties for the irregularly shaped and chemically heterogeneous soil particles. Advancing contact angles were determined by using model soils varying in texture from clay to coarse sand to check the impact of grain size on the CA measurements. Varying the solid‐surface tension with dichlorodimethlylsilane treatments provided for pure‐water wetting stages ranging from wettable to extremely hydrophobic. The surface tensions of the liquids were varied from 72 mN m^–1 to 25 mN m^–1 by using water or water‐ethanol mixtures. The surface tensions of the model soils were determined with the zero degree–contact angle method following Zisman's critical–surface tension concept. Results show that the measured CA varied continuously with the variations of the surface tension of the liquid and the solid phase, respectively. A general interpretation of the results is possible by using the concept of the Equation of State Approach.     

COMPUTED TOMOGRAPHY AND POSITIVE CONTRAST COMPUTED TOMOGRAPHIC ARTHROGRAPHY OF THE CANINE SHOULDER: NORMAL ANATOMY AND EFFECTS OF LIMB POSITION ON VISIBILITY OF SOFT TISSUE STRUCTURES

Soft tissue injuries of the shoulder are an important cause of forelimb lameness in dogs. The objectives of this canine cadaver study were to describe normal anatomy of shoulder soft tissue structures using computed tomography (CT) and computed tomographic arthrography (CTA) and to determine the effects of positioning on visualization of shoulder soft tissue structures. Thirteen forelimbs were removed from eight canine cadavers. Two forelimbs were used for contrast dose optimization. For the remaining 11 forelimbs, shoulder CT and CTA were performed using three defined joint angles (140°, 90°, and 70°). For three forelimbs, CT and CTA images were compared with frozen anatomic sections to describe normal anatomy. Ten forelimbs were used for analysis of positioning effects. Soft tissue structures evaluated were the joint capsule, cartilage, ligaments, tendons, and muscles. A visual assessment score was assigned to each structure using a consensus of two observers. The range and mode of scores were calculated and compared for each modality and limb position. The shoulder joint capsule and medial and lateral glenohumeral ligaments were completely visible with CTA. All tendons and muscles were visualized in all the examinations except for the teres minor muscle tendon and the coracobrachialis muscle, which were not visible on all scans. Positioning the limb in an extended position significantly improved visualization of most soft tissue shoulder structures. Shoulder cartilage was best seen with CTA and with neutral or flexed positioning of the shoulder. Findings indicated that both CT and CTA are feasible imaging techniques for visualization of soft tissue structures of the canine shoulder.