International disease surveillance. International disease monitoring, October to December 2004

To assess whether the rates of antimicrobial susceptibility in bacteria isolated from the urine of dogs with urinary tract infections are similar to those of bacteria isolated from bitches with pyometra, the antimicrobial resistance of Escherichia coli isolated from the two groups were determined and compared. The samples were collected in Sweden between April 2002 and March 2003, and potential changes over time were assessed by comparing the results with corresponding data from 1991 to 1993. Among 80 isolates of E coli from cases of pyometra, the proportions that were resistant to the antimicrobials used in canine practice were generally low (ampicillin 10 per cent, enrofloxacin 4 per cent, gentamicin 0 per cent, streptomycin 5 per cent, sulfamethoxazole 8 per cent, tetracycline 4 per cent and trimethoprim 2 per cent) and similar to the proportions reported previously. Significantly lower proportions of resistance were recorded among the pyometra isolates than among 92 isolates from urine samples submitted by animal hospitals to ampicillin (P=0.04), streptomycin (P=0.002) and tetracycline (P=0.03), but there were no differences between the pyometra isolates and 113 isolates from urine samples submitted by animal clinics.     

Solid substrate for production of Alternaria alternata conidia: a potential mycoherbicide for the control of Eichhornia crassipes (water hyacinth)

Eichhornia crassipes (water hyacinth), a major aquatic weed in India, is one of the targets in a biological weed control research programme in India. A fungal pathogen, Alternaria alternata, is being evaluated as a biological control agent for this weed. The feasibility of solid substrate for the mass production of A. alternata has been examined. Conidia production and virulence of A. alternata were affected by temperature, light and incubation period. The highest number of conidia were produced on rice seed followed by wheat, sorghum, maize seeds and cornmeal at 20°C when exposed to near‐ultraviolet than on the other substrates, while the least conidia were observed on these substrates under light conditions. At 20°C, large numbers of virulent conidia were produced on rice seeds after 4 weeks of incubation under constant dark conditions. Henceforth, the use of rice seeds as a solid substrate for production of A. alternata could be a feasible method to produce conidia in a village co‐operative scenario in India.     

Effect of Insemination–Ovulation Interval and Addition of Seminal Plasma on Sow Fertility to Insemination of Cryopreserved Sperm

In swine, the use of frozen-thawed (FT) sperm for artificial insemination (AI) is limited because of poor sow fertility, possibly associated with a post-thaw capacitation-like status resulting in fewer fully viable sperm. Sow fertility to AI with FT sperm may improve with deeper deposition of sperm within the female tract, insemination very close to ovulation, or reversal of cryocapacitation by seminal plasma (SP). We performed two experiments to examine these suggestions. In experiment 1, 122 multiparous Yorkshire sows received 600 IU equine chorionic gonadotrophin at weaning and 5 mg pLH 80 h later to control time of ovulation. The predicted time of ovulation (PTO) was 38 h after pLH injection. Thereafter, sows were assigned on the basis of parity to a single AI of FT sperm at 2 h before PTO, or at 12 h before PTO, or FT sperm supplemented with 10% SP at 12 h before PTO. Control sows received fresh semen at 12 h before PTO. All semen doses were adjusted to 3 x 10(9) live cells and deposited into the cervix. Experiment 2 employed 99 multiparous crossbred sows and repeated the treatments of experiment 1 except that all FT inseminations were intrauterine. In both experiments, farrowing rates were lower (p < 0.01) following FT inseminations with no effect of time of insemination or of supplemental SP. In experiment 1, litter size was smaller following FT insemination (p < 0.05), but no effect on litter size was evident in experiment 2. Supplemental SP had no effect on litter size in either experiment. The lack of effect of either SP or timing of FT insemination on sow fertility suggests that the non-lethal sperm cryoinjury affecting fertility involves more than just cryocapacitation.     

Polymorphs of Alumina Predicted by First Principles: Putting Pressure on the Ruby Pressure Scale

Fully optimized quantum mechanical calculations indicate that Al2O3 transforms from the corundum structure to the as yet unobserved Rh2O3 (II) structure at about 78 gigapascals, and it further transforms to Pbnm-perovskite structure at 223 gigapascals. The predicted x-ray spectrum of the Rh2O3 (II) structure is similar to that of the corundum structure, suggesting that the Rh2O3 (II) structure could go undetected in high-pressure x-ray measurements. It is therefore possible that the ruby (Cr3+-doped corundum) fluorescence pressure scale is sensitive to the thermal history of the ruby chips in a given experiment.     

An Economics Approach to Hard Computational Problems

A general method for combining existing algorithms into new programs that are unequivocally preferable to any of the component algorithms is presented. This method, based on notions of risk in economics, offers a computational portfolio design procedure that can be used for a wide range of problems. Tested by solving a canonical NP-complete problem, the method can be used for problems ranging from the combinatorics of DNA sequencing to the completion of tasks in environments with resource contention, such as the World Wide Web.