Investigation of Johne's disease in Tasmanian fallow deer (Dama dama)

In 2012 when many sheep flocks in northern‐central Tasmania were experiencing a high prevalence of ovine Johne's disease, 34 wild adult fallow deer shot on or near infected properties were negative to microscopic Mptb lesions of the ileo‐caecal valve, terminal ileum and ileo‐caecal lymph nodes. This study demonstrated 95% confidence of detecting Johne's disease in this fallow deer population if ≥10% of animals were shedding Mycobacterium avium subsp. paratuberculosis in their faeces, or if ≥21% of animals were sub‐clinically infected.     

Genetic linkage of the Yr1 and Pm4 genes for stripe rust and powdery mildew resistances in wheat

Summary Genes Yr1 for resistance to stripe rust and Pm4a for resistance to powdery mildew showed linkage of 2.0±0.6 cM. Close repulsion linkage probably accounts for the absence in European wheats of genes Yr1 and Pm4b in combination.     

Echinococcus granulosus in the Northern Territory,Australia: hydatid disease reported in beef cattle from the region

Hydatid disease in beef cattle has been reported to be widespread throughout Australia, but cattle bred and raised in the Northern Territory were previously believed to be free of the disease. Between 2010 and 2016, 1061 cattle from the Northern Territory were slaughtered at a New South Wales abattoir and inspected for hydatid disease. The proportion of cattle reported infected with hydatid disease was 3.5%. Individual cattle identification numbers indicated that the cattle included in the study had most likely remained within the Northern Territory from birth until immediately prior to slaughter, so were assumed to have become infected within the region. We suspect that the sylvatic cycle of Echinococcus granulosus transmission could be responsible for infection of cattle in this region.     

Bragg diffraction from crystallized ion plasmas

Single crystals of a one-component plasma were observed by optical Bragg diffraction. The plasmas contained 10(5) to 10(6) single-positive beryllium-9 ions (9Be+) at particle densities of 10(8) to 10(9) per cubic centimeter. In approximately spherical plasmas, single body-centered cubic (bcc) crystals or, in some cases, two or more bcc crystals having fixed orientations with respect to each other were observed. In some oblate plasmas, a mixture of bcc and face-centered cubic ordering was seen. Knowledge of the properties of one-component plasma crystals is required for models of white dwarfs and neutron stars, which are believed to contain matter in that form.     

Hydrogen radicals, nitrogen radicals, and the production of O3 in the upper troposphere

The concentrations of the hydrogen radicals OH and HO2 in the middle and upper troposphere were measured simultaneously with those of NO, O3, CO, H2O, CH4, non-methane hydrocarbons, and with the ultraviolet and visible radiation field. The data allow a direct examination of the processes that produce O3 in this region of the atmosphere. Comparison of the measured concentrations of OH and HO2 with calculations based on their production from water vapor, ozone, and methane demonstrate that these sources are insufficient to explain the observed radical concentrations in the upper troposphere. The photolysis of carbonyl and peroxide compounds transported to this region from the lower troposphere may provide the source of HOx required to sustain the measured abundances of these radical species. The mechanism by which NO affects the production of O3 is also illustrated by the measurements. In the upper tropospheric air masses sampled, the production rate for ozone (determined from the measured concentrations of HO2 and NO) is calculated to be about 1 part per billion by volume each day. This production rate is faster than previously thought and implies that anthropogenic activities that add NO to the upper troposphere, such as biomass burning and aviation, will lead to production of more O3 than expected.     

Sensitivity of boreal forest carbon balance to soil thaw

We used eddy covariance; gas-exchange chambers; radiocarbon analysis; wood, moss, and soil inventories; and laboratory incubations to measure the carbon balance of a 120-year-old black spruce forest in Manitoba, Canada. The site lost 0.3 +/- 0.5 metric ton of carbon per hectare per year (ton C ha-1 year-1) from 1994 to 1997, with a gain of 0.6 +/- 0.2 ton C ha-1 year-1 in moss and wood offset by a loss of 0.8 +/- 0.5 ton C ha-1 year-1 from the soil. The soil remained frozen most of the year, and the decomposition of organic matter in the soil increased 10-fold upon thawing. The stability of the soil carbon pool ( approximately 150 tons C ha-1) appears sensitive to the depth and duration of thaw, and climatic changes that promote thaw are likely to cause a net efflux of carbon dioxide from the site.     

Benign masses in the pericardium of two dogs

Two miniature Schnauzer dogs were treated for pericardial masses. In one dog the mass consisted of necrotic fat that was attached to the apex of the pericardium by a pedicle. No obvious communication with the abdomen was present. The second dog had a peritoneopericardial hernia associated with a chronic cystic haematoma. In each case the mass was presumed to have arisen following congenital displacement of the omentum into the pericardium. The pericardial mass was removed and subtotal pericardectomy performed in both dogs. Recovery was complete in each case.