Pyrolysing poultry litter reduces N2O and CO2 fluxes.

Application of poultry litter (PL) to soil can lead to substantial nitrous oxide (N2O) emissions due to the co-application of labile carbon (C) and nitrogen (N). Slow pyrolysis of PL to produce biochar may mitigate N2O emissions from this source, whilst still providing agronomic benefits. In a corn crop on ferrosol with similarly matched available N inputs of ca. 116 kg N/ha, PL-biochar plus urea emitted significantly less N2O (1.5 kg N2O-N/ha) compared to raw PL at 4.9 kg N2O-N/ha. Urea amendment without the PL-biochar emitted 1.2 kg N2O-N/ha, and the PL-biochar alone emitted only 0.35 kg N2O-N/ha. Both PL and PL-biochar resulted in similar corn yields and total N uptake which was significantly greater than for urea alone. Using stable isotope methodology, the majority (~80%) of N2O emissions were shown to be from non-urea sources. Amendment with raw PL significantly increased C mineralisation and the quantity of permanganate oxidisable organic C. The low molar H/C (0.49) and O/C (0.16) ratios of the PL-biochar suggest its higher stability in soil than raw PL. The PL-biochar also had higher P and K fertiliser value than raw PL. This study suggests that PL-biochar is a valuable soil amendment with the potential to significantly reduce emissions of soil greenhouse gases compared to the raw product. Contrary to other studies, PL-biochar incorporated to 100mm did not reduce N2O emissions from surface applied urea, which suggests that further field evaluation of biochar impacts, and methods of application of both biochar and fertiliser, are needed.

Improving the statistical preparation for measuring soil N2O flux by closed chamber.

Nitrous oxide emissions from soil are known to be spatially and temporally volatile. Reliable estimation of emissions over a given time and space depends on measuring with sufficient intensity but deciding on the number of measuring stations and the frequency of observation can be vexing. The question of low frequency manual observations providing comparable results to high frequency automated sampling also arises. Data collected from a replicated field experiment was intensively studied with the intention to give some statistically robust guidance on these issues. The experiment had nitrous oxide soil to air flux monitored within 10 m by 2.5 m plots by automated closed chambers under a 3h average sampling interval and by manual static chambers under a three day average sampling interval over sixty days. Observed trends in flux over time by the static chambers were mostly within the auto chamber bounds of experimental error. Cumulated nitrous oxide emissions as measured by each system were also within error bounds. Under the temporal response pattern in this experiment, no significant loss of information was observed after culling the data to simulate results under various low frequency scenarios. Within the confines of this experiment observations from the manual chambers were not spatially correlated above distances of 1m. Statistical power was therefore found to improve due to increased replicates per treatment or chambers per replicate. Careful after action review of experimental data can deliver savings for future work.

Carriage of methicillin-resistant Staphylococcus aureus by veterinarians in Australia.

OBJECTIVE: To estimate the prevalence of carriage of methicillin-resistant Staphylococcus aureus (MRSA) among Australian veterinarians. METHODS: Individuals attending veterinary conferences in Australia in 2009 were recruited to provide nasal swabs and complete a questionnaire about their professional activities. Swabs were processed by standard methods for detecting MRSA and questionnaire responses were used to group veterinarians according to their areas of major work emphasis (species and practice type). Prevalence was estimated for each of these grouping and contingency tables and regression tree analysis used to explain the variation in MRSA carriage. RESULTS: Among the 771 respondents 'industry and government veterinarians' (controls) had the lowest prevalence of MRSA carriage at 0.9%. Veterinarians with horses as a major area of work emphasis had a prevalence of 11.8% (13-fold that of controls) and those whose only major emphasis was horses had a prevalence of 21.4% (23-fold that of controls). Veterinarians with dogs and cats as a major activity had a 4.9% prevalence (5-fold that of controls). Prevalence rates for other major activities (pigs, dairy and beef cattle, avian and wildlife) were also increased, but were estimated from smaller numbers of respondents. Regression tree analysis clearly isolated equine veterinarians and dog and cat practitioners as groups at increased risk of carriage of MRSA. CONCLUSION: Carriage of MRSA is a notable occupational health issue for veterinarians in clinical practice in Australia, particularly those who work with horses.

Mass screening for antimicrobial resistant Escherichia coli in dairy cows in northern New South Wales.

OBJECTIVE: To describe aspects of the epidemiology of antimicrobial resistance in Escherichia coli shed in the faeces of milking cows in a dairying region of New South Wales. DESIGN: A survey based on multi-stage sampling with repeated measures made within herds for estimating within-herd correlation of resistance status, and with repeated measures made on identical specimens for estimating test-retest reliability. PROCEDURE: From a population of 110 dairy herds, 30 were selected at random and from each herd between 5 and 10 faecal specimens were obtained from fresh manure pats. E coli from faecal specimens were grown on hydrophobic grid membrane filters (HGMF) and replicated onto chromogenic agar and agar containing antimicrobials (gentamicin, ampicillin, tetracycline and sulfamethoxazole). Image analysis was used to assess colony growth. Data were analysed descriptively, by generalised linear mixed models and by Taylor series linearisation to account for attributes of the survey design. RESULTS: Of the 10,279 E coli isolates assessed, 91% expressed no resistance, 7.3% were resistant to sulfamethoxazole, 3.6% to tetracycline, 2.2% to ampicillin and 0.09% to gentamicin. The most common multiple resistance phenotype was ampicillin-tetracycline-sulfamethoxazole (1.8% of isolates). Most multiple resistant isolates appeared clustered within particular herds but were too rare to obtain valid estimates of variance, confidence intervals or intra-herd correlation. The estimated proportion of isolates in the population that were susceptible to all four antimicrobials was 97% (95% CI: 91% to 100%) and 55% of cows had no resistance detected in faecal E coli (95% CI: 27% to 83%). Within-herd correlation of shedding status (any resistance pattern) was absent and test-retest reliability of the measurement system was estimated to be at the lower end of good (0.40) but increased to excellent (0.89) after excluding sulfamethoxazole resistance, which had a greater measurement error. CONCLUSION: Antimicrobial resistance was uncommon in E coli in the population of dairy cows studied. HGMF and image analysis is an effective tool for detecting rare forms of resistant E coli that are not uniformly distributed in livestock populations.

Nitrogen and phosphorus removal from plant nursery runoff in vegetated and unvegetated subsurface flow wetlands.

Subsurface horizontal flow reed beds are being evaluated for Nitrogen (N) and Phosphorus (P) removal from plant nursery runoff water in New South Wales Australia. The need to include plants (Phragmites australis), the effect of reaction time (3.5 v 7.0 d) and dissolved organic carbon (DOC) on N and P removal in batch fed gravel wetland tubs (55 L) was studied over 19 months. Simulated nursery runoff water containing N (10.1 mg L(-1), 74% as NO3) and P (0.58 mg L(-1), 88% as PO4) and DOC (2-5 mg L(-1)) was used. The planted wetland tubs removed >96% TN and TP over most of the 19-month study period while unplanted tubs were inefficient (<16% N and <45% P removal) and occasionally discharged nutrients. Doubling the reaction time to 7.0 days had no effect on nutrient removal. Plant nutrient uptake accounted for most of the N (76%) and P (86%) removed while roots and rhizomes were the dominant sink (N 58%, P 67%). The addition of methanol (C:N-3:1) to unplanted tubs achieved 81-98% N removal. In Carbon limited low nutrient nursery runoff, plants were essential to a gravel-based wetland to achieve efficient nutrient removal with effluent TN and TP concentrations of <1 mg L(-1) and 0.05 mg L(-1), respectively with a 3.5 day reaction time.

The relationship between concentration of a dual marker strain of Salmonella Typhimurium in bovine faeces and its probability of detection by immunomagnetic separation and culture.

AIMS: To modify a strain of Salmonella serotype Typhimurium to express unique marker traits and then define how the concentration of the marker in bovine faeces affects the probability of its detection by culture preceded by immunomagnetic separation (IMS). METHODS AND RESULTS: DNA encoding for the production of green fluorescent protein (gfp) and resistance to kanamycin was inserted into the bacterial chromosome of Salm. Typhimurium. Transposon insertion was demonstrated by Southern blot hybridization. Varying amounts of one electroporant (gfpSal-1) were inoculated into suspensions of bovine faeces and attempts made to isolate gfpSal-1 using a protocol based on pre-enrichment incubation, IMS and enrichment in selective media. Isolates of gfpSal-1 were differentiated from wild strains of Salmonella using fluorescence under u.v. light and expression of kanamycin resistance. A logistic and Gompertz function each derived from the dose-response data partially explained the observations with the fit of the Gompertz function judged to be superior. The 10, 50 and 90% limits of detection from the Gompertz function were estimated to be 1.92, 2.03 and 2.27 CFU g(-1) respectively. CONCLUSIONS: Reliance on the traditional concept of 'limit of detection' could introduce unacceptable errors in the interpretation of test findings when the concentration of Salm. Typhimurium in bovine faeces (pooled or individual) is below ca 3 CFU g(-1) of faeces. SIGNIFICANCE AND IMPACT OF THE STUDY: The dose-response curve can be used to aid the design of protocols for detecting Salmonella in individual and pooled faecal specimens. The experiments demonstrate that both reporter genes in tandem are useful for studying the performance of culture-based methods for detecting pathogens in faeces.

Salvage first MTP arthrodesis utilizing ICBG: clinical evaluation and outcome.

Twelve patients (12 feet) underwent salvage first metatarsalphalangeal (MTP) arthrodesis with structural, interposition autologous iliac crest bone graft (ICBG). Eight patients had a bony defect secondary to failed first MTP joint implant arthroplasties, two had avascular necrosis (AVN) after failed bunion surgery, one had a nonunion of an attempted arthrodesis for failed bunion surgery, and one had been treated for osteomyelitis after cheilectomy. Eleven of the cases had a single dorsal plate secured by screws and one case had two plates, one dorsal and one medial. A plate, crossed screw(s) and/or K-wire combination were chosen in four cases. Indications included first MTP joint pain, metatarsalgia, intractable plantar keratoses (IPK), as well as a functionally and cosmetically short first ray refractory to non surgical management. Average preoperative shortening was 8.5 mm (range 5-17). Clinical arthrodesis was achieved after an average of 12 weeks (range 4-20). Radiographic arthrodesis was achieved in eleven of twelve feet at an average of 15 weeks (range 8-28), with one pseudoarthrosis. AOFAS forefoot clinical rating score averaged 70 points (max 90 after first MTP arthrodesis) at an average follow-up of 22 months (range 5-70). Sesamoiditis, prominent hardware and scar sensitivity were prevalent complaints in four patients postoperatively. Two cases required flap coverage for skin necrosis. Relief of metatarsalgia, good hallux alignment as well as improved patient satisfaction and function were achieved in all cases. There was no symptomatic progression of interphalangeal degenerative change postoperatively.

Midfoot field block anesthesia with monitored intravenous sedation in forefoot surgery.

Fifty consecutive patients, studied prospectively, underwent an elective first metatarsophalangeal joint arthrodesis or proximal metatarsal osteotomy and modified McBride bunionectomy, with or without concomitant lesser toe procedures. A field block was administered only at and distal to the level of the tarsometatarsal joints using 30 cc equal parts 0.25% bupivacaine and 1% lidocaine without epinephrine. Before injection, the monitoring anesthesiologist gave the patient intravenous (IV) sedation, usually an amnestic agent. Narcotic analgesia was not given to any patient before or during surgery to evaluate the efficacy of the block. Detailed records were kept of all intraoperative medication and its dosage, including supplemental local anesthetic. Efficacy and outcome were measured via direct patient monitoring during surgery and by direct interview after surgery, first in the recovery area (visual pain analogue applied) and again at 24 to 48 hr after surgery (recollection of events, duration of block, use of narcotics after surgery, subjective patient satisfaction). Supplemental local anesthetic was required for 15 patients (primarily for those who underwent lesser toe procedures), IV narcotic was required for 3 patients, and conversion to general anesthesia was required for 4 patients for agitation, not pain. The average duration of the local block was 8 hr (range, 5-14 hr); none of the patients had recall of negative events, and overall patient satisfaction was 98%. Midfoot blocks are easy to administer and provide reliable anesthesia for reconstructive forefoot surgery. Monitored IV sedation enhances patient acceptance, facilitates block administration, and provides a valuable measure of patient safety and comfort.

Massive bone allografts for traumatic skeletal defects.

Large bone allograft transplants have been successfully used to reconstruct skeletal defects created by tumor resections and failed arthroplasties, but little has been reported on their use in traumatic defects. Of approximately 500 allograft procedures done at the Massachusetts General Hospital from 1979 to 1988, 11 were done for restoration of traumatic bone loss. The average age of the patients was 30 (range 11 to 71 years), and the location of the defect was the tibia or femur in 10 of the 11 patients studied. Eight osteoarticular grafts (six hemicondylar and two total condylar) and three intercalary grafts were used for six open and five closed fractures. The time from injury to reconstruction averaged 17 months (3 to 96 months). Primary reconstruction was done in three cases and a salvage procedure in eight. Patients were assessed by the operating surgeon and a physical therapist using an evaluation system that considers function, life-style, and emotional acceptance. According to the system, nine patients had excellent or good results (six hemicondylar grafts, three intercalary grafts), one patient had a fair result (total elbow graft), and one patient had failure of a total condylar graft and subsequently required an amputation. This study suggests that large bone allografts are of value in reconstructing traumatic skeletal defects, especially those involving an articular surface in a young patient.

Resection and reconstruction for soft-tissue sarcomas of the extremity.

Soft-tissue sarcomas are uncommon malignant tumors, and when a diagnosis is made early, the patient has up to an 80% chance of surviving. In treating soft-tissue sarcomas, the goal of the surgeon is the prolongation of patient survival, the total eradication of local disease, and the minimization of functional deficits. In addition to treatment, this article discusses evaluation, histology, and staging.

Administering audiometric speech tests via bone conduction: a comparison of transducers.

This study compared the intelligibility of speech delivered via three transducers: a TDH-39 earphone, a Pracitronic KH 70 bone vibrator, and a Radioear B-72 bone vibrator. CID W-1 spondees were presented to normal-hearing listeners via each transducer over a range of intensity levels. Functions relating the percentage of spondees correctly identified to stimulus level were similar for the three transducers, and notably, their slopes were comparable. This suggests that it is appropriate to use the W-1 word lists to determine speech reception thresholds (SRTs) with the KH 70 and B-72 bone vibrators, even though these word lists were originally developed for testing by air conduction. Our subjects also identified NU-6 monosyllabic words equally well for each transducer when the words were delivered at 40 dB above SRT. This result suggests that it is also valid to deliver the NU 6 speech test via the two types of bone vibrators.

Use of health services before diagnosis of head and neck cancer among Boston residents.

One hundred thirty incident cases of head and neck cancer in Boston between September 1, 1985, and March 31, 1988, provided interview or medical record review data on the use of health services in the 24 months preceding the diagnosis of cancer. One hundred twenty-four subjects were able to recall whether and how often they visited health care sites in this period, reporting a median number of 10.5 visits; 94% recalled at least one visit. Eighty-nine medical record reviews indicated a median of seven visits. For the most part, these visits were to providers whom subjects considered their regular source of care--sources that provided care in a broad range of locations. These data support a strategy of integrating screening for head and neck cancers into existing health care services.