Shear stress and dispersion as affected by flow of sodium ion solutions through clayey soil

An attempt was made to quantitatively investigate the effect of surface shear stress or strength on soil dispersion. This effect was estimated from the shear stress induced by a flow of different NaCl concentrations at pressure differences of1, 10 and 100 kPa. The results showed that flow rate, shear stress and soil dispersion were increased by increasing applied pressure. At high pressure (100 kPa), shear stress increased from 33.75 to 122.5 kPa at 0.185 and 1.0 M NaCl, respectively. At any pressure difference, the dispersion index decreased with increasing Na⁺ concentration under flow conditions.     

A tunable kondo effect in quantum dots

A tunable Kondo effect has been realized in small quantum dots. A dot can be switched from a Kondo system to a non-Kondo system as the number of electrons on the dot is changed from odd to even. The Kondo temperature can be tuned by means of a gate voltage as a single-particle energy state nears the Fermi energy. Measurements of the temperature and magnetic field dependence of a Coulomb-blockaded dot show good agreement with predictions of both equilibrium and nonequilibrium Kondo effects.     

Antagonism of detomidine with tolazoline in isoflurane-anaesthetised ponies

The effects of tolazoline (4.0 mg/kg iv) antagonism of detomidine (0.02 mg/kg iv) were evaluated in isoflurane-anaesthetised, ventilated ponies. Each of 6 ponies received both tolazoline and saline treatment during separate anaesthetic episodes only (no surgery was performed). Detomidine administration produced an increase in blood pressure, decrease in heart rate and decrease in P_aO₂ Tolazoline treatment transiently increased heart rate while blood pressure returned to baseline after both treatments. Arterial oxygenation decreased further after tolazoline treatment while oxgenation recovered towards baseline with saline treatment. No other cardiopulmonary effects were detected. Recovery from anaesthesia tended to be more rapid when detomidine was antagonized. The potential benefit of antagonizing detomidine-induced bradycardia with tolazoline, during isoflurane anaesthesia should be weighed against the potential to produce a decrease in arterial oxygenation. The mechanism for this effect is not clear.     

Capacitation of Frozen Thawed Buffalo Bull (Bubalus bubalis) Spermatozoa with Higher Heparin Concentrations

The present study was conducted to examine the effect of high heparin concentration on capacitation of buffalo spermatozoa with a short incubation time. Frozen thawed spermatozoa from three buffalo bulls were pooled and treated with either 50, 100 or 200 microg/ml heparin for 30 min. Capacitation was evaluated by acrosome reaction of spermatozoa and in vitro fertilization rate (per cent cleavage rate, per cent cleavage index). Acrosome reaction was induced in heparin treated spermatozoa with calcium ionophore A23187 and staining was carried out with Coomassie G-250 to evaluate the response as compared with control (0 heparin + calcium ionophore). Significantly higher percentage of acrosome reaction (AR) spermatozoa was noted after heparin treatment (36.8-48.2%) as compared with control (8.1% ; p < 0.05) but differences among the three heparin concentrations were non-significant. However, a significantly higher in vitro fertilization rate was recorded in spermatozoa capacitated by 50 and 100 microg/ml heparin (80.4 and 75.9% cleavage rate, respectively) as compared with 200 microg/ml heparin (47.2% cleavage rate; p < 0.001). It is concluded that buffalo spermatozoa capacitated with 50-100 microg/ml heparin had significantly higher ability to improve in vitro fertilization rate in buffalo.     

Visceral mast cell tumour with eosinophilia and eosinophilic peritoneal and pleural effusions in a cat

Summary A cat with weight loss, pyrexia and recurrent lethargy and depression was found to have pleural and peritoneal eosinophilic effusions, peripheral eosinophilia, eosinophilic lymphadenitis and a massively enlarged mesenteric lymph node. Visceral mast cell neoplasia was diagnosed after histopathological examination of a biopsy of the mass. Palliative chemotherapy was attempted unsuccessfully and the cat was euthanased.     

Impact of alum on crust prevention and aggregation of calcareous soil: laboratory studies

Alum was applied at rates of 0.01, 0.02, 0.05, 0.1 and 0.2% by weight to a calcareous silty clay soil in an attempt to reduce soil crusting and improve soil aggregation. Results indicated that the modulus of rupture (MR) was reduced from 176 to 60 kPa with the addition of 0.2% alum. The mean weight diameter (MWD) was doubled when the application rate of alum increased from 0 to 0.2%. Alum apparently modified the soil physical environment by making the soil fluffy which in turn reduces its MR. Gypsum was formed by the reaction of alum with calcium carbonate in proportion to the amount of alum applied, increasing from 0.2% in the control soil to 1.1% with the highest rate of alum applied. This increase may have lead to the reduction in the MR and an increase in the MWD. This research showed that alum was effective in improving soil aggregate stability and decreasing aggregate rupture stress.     

Impact of Field Application of Treated Wastewater on Hydraulic Properties of Vertisols

Fifteen soil profiles were taken from Ar-Ramtha wastewater treatment plant, 65 km north of Amman. Twelve of them represent soil planted with barley and irrigated with wastewater for the past 2, 5, and 15 years. The remaining three profiles represented a control area that has been only rainfed. Soil samples were collected in four replicates from each depth in each soil profile. Field and laboratory experiments were conducted to study the effect of irrigation with treated wastewater on hydraulic properties of surface and subsurface vertisols. Soil infiltration rate (IR), hydraulic conductivity (HC), and water retention (at 33 kPa and 1.5 MPa) were measured. The application of wastewater for 2, 5, and 15 years reduced soil hydraulic conductivity, whereas the infiltration rate decreased for 2 and 5 years, compared with non-irrigated area. Sites irrigated for 15 years with treated wastewater are characterized by higher percentages of large cracks, therefore revealed the highest infiltration rate. Soil available water changed due to wastewater application in decreasing order of: control (rainfed), 15, 5, 2 years of wastewater application.     

Molecular characterization of Mycoplasma gallisepticum isolates from Jordan

Two groups of Mycoplasma gallisepticum (MG) isolates (n = 24) from Jordan were analyzed by molecular methods and compared with other Middle Eastern isolates, related international isolates, and reference strains. The first group (n = 19) was isolated from July 2004 to January 2005 (isolation period A), and the newer group (n = 5) from June 2007 to April 2008 (isolation period B). The groups of isolates are from chicken flocks from northern Jordan, but are not from the same farms. None of the flocks were vaccinated for MG. Random amplified polymorphic DNA analysis, targeted sequencing of the partial MG cytadhesin 2 (mgc2), and the MG 16S-23S rRNA intergenic spacer region (IGSR) divided the Jordanian isolates into two groups. All of the 19 isolates from time period A, in addition to two isolates from time period B, were indistinguishable from the F strain. Three of five isolates from time period B were characterized as wild types and were indistinguishable from each other. The wild-type field strain was readily distinguished from the F strain. It was 91% and 96.4% similar to the F strain based on Clustal-W alignments of sequences of mgc2 and IGSR, respectively. Sequence similarity of mgc2 gene of the Jordan wild-type strain to isolates from Israel and Egypt ranged from 96.5% to 100%, whereas for IGSR it was 99.4%-100%. We theorize that the F-strain live MG vaccine, commonly used in Jordan prior to 2007, was transmitted to nonvaccinated poultry in the region and was a predominant genotype during time period A.