Dynamics of Saturn's south polar vortex

The camera onboard the Cassini spacecraft has allowed us to observe many of Saturn's cloud features. We present observations of Saturn's south polar vortex (SPV) showing that it shares some properties with terrestrial hurricanes: cyclonic circulation, warm central region (the eye) surrounded by a ring of high clouds (the eye wall), and convective clouds outside the eye. The polar location and the absence of an ocean are major differences. It also shares properties with the polar vortices on Venus, such as polar location, cyclonic circulation, warm center, and long lifetime, but the Venus vortices have cold collars and are not associated with convective clouds. The SPV's combination of properties is unique among vortices in the solar system.     

The geological evolution of the Tibetan Plateau

The geological evolution of the Tibetan plateau is best viewed in a context broader than the India-Eurasia collision zone. After collision about 50 million years ago, crust was shortened in western and central Tibet, while large fragments of lithosphere moved from the collision zone toward areas of trench rollback in the western Pacific and Indonesia. Cessation of rapid Pacific trench migration ( approximately 15 to 20 million years ago) coincided with a slowing of fragment extrusion beyond the plateau and probably contributed to the onset of rapid surface uplift and crustal thickening in eastern Tibet. The latter appear to result from rapid eastward flow of the deep crust, probably within crustal channels imaged seismically beneath eastern Tibet. These events mark a transition to the modern structural system that currently accommodates deformation within Tibet.     

From land and sea,long‐term data reveal persistent humpback whale (Megaptera novaeangliae) breeding habitat in New Caledonia

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The effect of antimicrobial treatment and preventive strategies on bovine respiratory disease and genetic relatedness and antimicrobial resistance of Mycoplasma bovis isolates in a western Canadian feedlot

Feedlot calves (n = 3784) were systematically randomized and allocated in a 2 × 2 factorial study to receive metaphylactic oxytetracycline (OTC) on arrival or no antimicrobial, as well as florfenicol once subcutaneously or twice intramuscularly (48 h apart) if diagnosed with bovine respiratory disease (BRD). Calves of different treatment groups were comingled and followed from placement to re-implantation (~100 days). Animals receiving OTC had a reduced risk of BRD, an increased risk of arthritis, and no significant differences in average daily gain, BRD relapse, overall mortality, or BRD mortality. There were no significant differences between treatment protocols. Deep nasal swabs (n = 233) taken at arrival (n = 122), treatment (n = 77), and swabs from lungs and joints at postmortem (n = 34) were cultured for Mycoplasma bovis from 61 animals ill or dying of chronic pneumonia and arthritis and from 61 healthy calves. There was significant variation in diversity among isolates (n = 51) between study years and different cattle. Metaphylaxis or antimicrobial treatment did not affect the diversity of isolates. Except for tilmicosin, isolates were largely susceptible to tested antimicrobials.     

Reducing seabird bycatch in longline, trawl and gillnet fisheries

With an increasing number of seabird species, particularly albatross and petrels, becoming threatened, a reduction of fishery impacts on these species is essential for their future survival. Here, mitigation methods to reduce and avoid seabird bycatch are assessed in terms of their ability to reduce bycatch rates and their economic viability for longline, trawl and gillnet fisheries worldwide. Factors influencing the appropriateness and effectiveness of a mitigation device include the fishery, vessel, location, seabird assemblage present and season of year. As yet, there is no single magic solution to reduce or eliminate seabird bycatch across all fisheries: a combination of measures is required, and even within a fishery there is likely to be refinement of techniques by individual vessels in order to maximize their effectiveness at reducing seabird bycatch. In longline demersal and pelagic fisheries, a minimum requirement of line weighting that achieves hook sink rates minimizing seabird bycatch rates should be tailored with a combination of strategic offal and discard management, bird‐scaring lines (BSLs) and night‐setting, particulary in Southern Hemisphere fisheries. Urgent investigation is needed into more effective measures at reducing seabird interactions with trawl nets and gill nets. In trawl fisheries, a combination of offal and discard management, the banning of net monitoring cables, paired BSLs, and a reduction in the time the net is on or near the surface are likely to be the most effective in reducing seabird interactions with the warp cables and net. Few seabird bycatch reduction methods have been developed for gillnet fisheries, although increasing the visibility of the net has been shown to reduce seabird bycatch. Further studies are required to determine the efficacy of this technique and its influence on target species catch rates.     

Use of 'thoracic stick' in halal slaughter of bobby calves

Throat cutting associated with halal slaughter of bobby calves fails to sever the vertebral arteries supplying the brain. Such slaughter may be inhumane due to calves recovering from the stun before permanent insensibility, due to blood loss, occurs. Interruption of the vertebral arteries may be achieved by severance of the brachiocephalic trunk or penetration of the heart by the use of a 'thoracic stick', an incision with a knife through the thoracic inlet.     

The significance of drilling date and crop cover with reference to soil erosion by water,with implications for mitigating erosion on agricultural land in South East England

Early drilling of autumn‐planted cereals is strongly advised in UK government publications targeted at farmers, in part as a measure to combat soil erosion by water. However, in years when rainfall is heavy in early autumn, this strategy is ineffective. Late drilling of autumn‐planted cereals also increases the risk of erosion, but for a different reason: crop cover develops more slowly in cooler weather, resulting in a longer exposure of nearly bare ground. The crucial factor affecting both strategies is the timing of autumn and early winter rainfall. We discuss a conceptual model based on the notion of a ‘window of opportunity’ for erosion, comprising the relationship between drilling date, date of attainment of a sufficiently protective crop cover and the timing of rainfall; variations are presented for different weather conditions and management choices. Of these three factors, only the date of drilling can be chosen by the farmer. The date of attaining a sufficiently protective crop cover can only be predicted approximately. The timing of rainfall cannot be predicted. Thus, erosion control advice to farmers, which is based on choice of date of drilling to minimize erosion during the ‘window of opportunity’, is both difficult to formulate and likely to be ineffective. Sites at risk of erosion need to have better thought‐out mitigation measures in place, rather than relying on a fortuitous temporal pattern of autumn and winter rainfall to minimize the risk of erosion.