The effect of periods of anaerobiosis on the storage of apples

An adequate supply of oxygen, to maintain aerobic metabolism, is essential during the storage of apples. One of the recommended conditions for storing Cox’s Orange Pippin apples is in 1.8 to 2.5% oxygen; sometimes this is attained by admitting nitrogen to the store. Inaccurate estimation of the oxygen content of the store can result in the fruit being deprived of oxygen and in the accumulation of alcohol in the tissues. If aerobic conditions are re-established, the alcohol content of the fruit decreases, but if the concentration is of the order of 200 mg alcohol/100 g fruit the apples become senescent before they lose the alcoholic flavour.

It has been suggested elsewhere that a preliminary anaerobic phase, lasting for a week at 3.5 °C, leads to improved turn-out of apples from C.A. storage. For the English cultivars tested this has not proved to be the case. Accidental or deliberate anaerobiosis is detrimental in other respects, apart from the accumulation of alcohol; losses from rotting are increased, and there may be a greater incidence of core flush and breakdown.     

Polyarthritis in wild mice (Mus musculus) caused by Streptobacillus moniliformis

SUMMARY Mice trapped on farms in south-eastern Queensland had chronic abscessating osteoarthritides mainly involving the carpi and tarsi. Pleomorphic bacteria were shown by silver staining to be plentiful within lesions. Streptobacillus moniliformis was isolated from the joints, and streptobacillary polyarthritis was diagnosed. Other lesions observed included subcutaneous and hepatic abscesses.     

Seroprevalence to Leptospira interrogans serovar hardjo in Merino stud rams in South Australia

Summary A serological survey of 2160 Merino stud rams on 36 farms detected positive reactions greater than or equal to 1/100 in 42% of animals using the microscopic agglutination test (MAT) to Leptospira interrogans serovar hardjo. Twenty flocks had seroprevalence values greater than 30% with 15 flocks having values 60%. The enzymelinked immunosorbent assays showed that 47% and 3% of rams on the 36 farms were positive for IgG and IgM antibodies, respectively. Forty-five percent of hardjo reactions were in rams that had not been exposed to cattle. Significant correlations were found between IgM reactors and creek/dam water pumped into troughs, and between MAT/IgG reactors and total flock size. No statistical relationships were detected between positive reactors and two different annual average rainfall gradients, the time of the year in which samples were obtained, or agricultural regions of South Australia. Infections with an organism of the Sejroe serogroup is widespread in Merino stud rams.     

The Effects of Water Temperature and Flow upon Angling Success in the River Severn

Angling catch data was gathered by a postal questionnaire system from angling clubs holding competitions in three sections of the River Severn over a period of 3 years (1975–78). Angling success was measured as the percentage of anglers taking part that caught fish and as the overall catch rate (g/man/h) of the competing anglers. Species composition of the catch was also recorded. Angling success was closely related to water temperature. Parabolic regressions were fitted to the data. Optimum temperatures for angling success were between 18 and 20°C, except for the Lower Severn section where maximum catch rates were achieved at 14.9°C. Flow had little effect upon angling success until a critical flow was reached, above which success was considerably reduced. Critical flows for the upper, mid and lower sections were approximately 3,000, 5,000 and 10,000 Ml/day, respectively. Species composition of catches within river sections was influenced by water temperature. Some species (bleak, bream, dace and eels) were relatively more abundant in catches made at high temperatures whilst others (chub and roach) predominated at tow temperatures. It is suggested that the percentage of anglers catching fish is the most reliable indicator of angling success.     

High-severity wildfire effects on carbon stocks and emissions in fuels treated and untreated forest

Forests contain the world's largest terrestrial carbon stocks, but in seasonally dry environments stock stability can be compromised if burned by wildfire, emitting carbon back to the atmosphere. Treatments to reduce wildfire severity can reduce emissions, but with an immediate cost of reducing carbon stocks. In this study we examine the tradeoffs in carbon stock reduction and wildfire emissions in 19 fuels-treated and -untreated forests burned in twelve wildfires. The fuels treatment, a commonly used thinning ‘from below’ and removal of activity fuels, removed an average of 50.3 Mg C ha⁻¹ or 34% of live tree carbon stocks. Wildfire emissions averaged 29.7 and 67.8 Mg C ha⁻¹ in fuels treated and untreated forests, respectively. The total carbon (fuels treatment plus wildfire emission) removed from treated sites was 119% of the carbon emitted from the untreated/burned sites. However, with only 3% tree survival following wildfire, untreated forests averaged only 7.8 Mg C ha⁻¹ in live trees with an average quadratic mean tree diameter of 21 cm. In contrast, treated forest averaged 100.5 Mg C ha⁻¹ with a live tree quadratic mean diameter of 44 cm. In untreated forests 70% of the remaining total ecosystem carbon shifted to decomposing stocks after the wildfire, compared to 19% in the fuels-treated forest. In wildfire burned forest, fuels treatments have a higher immediate carbon ‘cost’, but in the long-term may benefit from lower decomposition emissions and higher carbon storage.