The exact evaluation of the corner-to-corner resistance of an M x N resistor network: Asymptotic expansion

We study the corner-to-corner resistance of an M x N resistor network with resistors r and s in the two spatial directions, and obtain an asymptotic expansion of its exact expression for large M and N. For M = N, r = s =1, our result is R_{NxN} = (4/pi) log N + 0.077318 + 0.266070/N^2 - 0.534779/N^4 + O(1/N^6).Comment: 12 pages, re-arranged section

Bacterial isolates from neutropenic febrile pediatric patients and their sensitivity patterns to antibiotics

Patients on cytotoxic therapy often develop neutropenia and fever. Our interest was to identify the common pathogens isolated from such patients and to study the sensitivity patterns of these organisms to the antibiotics used in their treatment. Thus, guidelines can be established by hospitals to identify which antibiotics can be used in the treatment of these patients when the results of cultures and sensitivities are not available. We conducted a retrospective study of neutropenic pediatrics presenting to AKUH from July, 1990 to June, 1996. A total of 153 isolates in 35 different patients were studied. Samples for culture were taken from the sites at risk. The majority of samples consisted of blood, stool, pus and urine. Twenty stool samples were also sent for microscopy. Malignancies were both hematological and non-hematological. Gram negatives were isolated in 52.9%, gram positives in 33.9% and parasites in 13.2%. Salmonella paratyphi B was the most commonly isolated organism, followed by Pseudomonas aeroginosa, Giardia lamblia was the most common parasite. Sensitivity patterns of these organisms to antibiotics studied showed that Escheria coli had the lowest sensitivity rate being only 40% sensitive to Aztreonam and 64% sensitive to Ofloxacillin. A comparison was made between our findings and those reported in literature, as well as the risk factors for developing neutropenia. A guide to management is also discussed

Inter-observer agreement of canine and feline paroxysmal event semiology and classification by veterinary neurology specialists and non-specialists

Background: Advances in mobile technology mean vets are now commonly presented with videos of paroxysmal events by clients, but the consistency of the interpretation of these videos has not been investigated. The objective of this study was to investigate the level of agreement between vets (both neurology specialists and non-specialists) on the description and classification of videos depicting paroxysmal events, without knowing any results of diagnostic workup. An online questionnaire study was conducted, where participants watched 100 videos of dogs and cats exhibiting paroxysmal events and answered questions regarding: epileptic seizure presence (yes/ no), seizure type, consciousness status, and the presence of motor, autonomic and neurobehavioural signs. Agreement statistics (percentage agreement and kappa) calculated for each variable, with prevalence indices calculated to aid their interpretation. Results: Only a fair level of agreement (kappa = 0.40) was found for epileptic seizure presence. Overall agreement of seizure type was moderate (kappa = 0.44), with primary generalised seizures showing the highest level of agreement (kappa = 0.60), and focal the lowest (kappa = 0.31). Fair agreement was found for consciousness status and the presence of autonomic signs (kappa = 0.21-0.40), but poor agreement for neurobehavioral signs (kappa = 0.16). Agreement for motor signs ranged from poor (kappa = <= 0.20) to moderate (kappa = 0.41-0.60). Differences between specialists and non-specialists were identified. Conclusions: The relatively low levels of agreement described here highlight the need for further discussions between neurology experts regarding classifying and describing epileptic seizures, and additional training of non-specialists to facilitate accurate diagnosis. There is a need for diagnostic tools (e.g. electroencephalogram) able to differentiate between epileptic and non-epileptic paroxysms

Molecular Characterization of Antibiotic Resistance in Poultry Gut Origin Enterococci and Horizontal Gene Transfer of Antibiotic Resistance to Staphylococcus aureus

Enterococci, the normal inhabitant of gastrointestinal tract of humans and animals, have emerged as significant antibiotic resistant nosocomial pathogens. The current study was designed to determine the antibiotic resistance profile and genes harbored by isolated strains of Enterococci along with study of antibiotic resistance transfer potential from resistant Enterococci to susceptible pathogenic Staphylococcus aureus in vitro. The PCR based prevalence of Enterococcus faecalis and Enterococcus faecium from 118 broiler cloacal swabs was 60.46 and 30.23%, respectively, indicating that E. faecalis is the predominant species in broilers followed by E. faecium. Enterococci (n=86) were examined for the phenotypic resistance against eleven antibiotics which showed higher level of resistance to lincomycin (96.51%), erythromycin (90.69%), tetracycline (86.04%) and streptomycin (75.58%), intermediate level of resistance to ciprofloxacin (54.65%) and doxycycline (48.83%), and low resistance level to penicillin (26.74%), chloramphenicol (26.74%), amoxicillin (17.44%), augmentin (11.62%) and vancomycin (10.46%). Over 80% Enterococcal isolates were found multidrug resistant (MDR). On the basis of PCR analysis, erm (B) and tet (M) genes were identified in all phenotypically erythromycin and tetracycline resistant strains while van (B) was identified in only 4/9 (44.4%) of vancomycin resistant enterococci (VRE) with no detection of van (A) gene in any VRE. One strain E. faecalis (FME-41) was able to transfer the erythromycin resistance to pathogenic Staphylococcus aureus (M-11) in broth mating assay.  MDR Enterococci pose therapeutic threat to human community and control on the spread of such MDR Enterococci from poultry to human food chain is crucial

Low-density series expansions for directed percolation III. Some two-dimensional lattices

We use very efficient algorithms to calculate low-density series for bond and site percolation on the directed triangular, honeycomb, kagom\'e, and $(4.8^2)$ lattices. Analysis of the series yields accurate estimates of the critical point $p_c$ and various critical exponents. The exponent estimates differ only in the $5^{th}$ digit, thus providing strong numerical evidence for the expected universality of the critical exponents for directed percolation problems. In addition we also study the non-physical singularities of the series.Comment: 20 pages, 8 figure