Impact of improved host resistance on worm control in Merinos - a computer simulation study

The WW model has been used to examine the epidemiological consequences of having a flock of resistant lambs as a result of either selective breeding or vaccination. However, these simulations started with "resistant" sheep rather than simulating the gradual change in immune response that would occur over a number of years in a breeding program

Polyethylene glycol is more effective than surfactants to enhance digestion and production in sheep fed mulga (Acacia aneura) under pen and paddock conditions

Chemicals that interfere with the formation of tannin-protein complexes were evaluated as dietary additives for mulga-fed sheep in pens and under paddock conditions. Condensed tannins (CT) in mulga inhibit protein digestion, and the use of chemicals to precipitate CT or dissociate CT-protein complexes may improve production from sheep consuming a mulga diet. In a digestion study with mulga-fed sheep in pens, provision of polyethylene glycol (PEG) at a rate of 6 g/day significantly (P < 0·05) improved nitrogen (N), phosphorus (P), and sulfur (S) balance, and apparent N, P, dry matter (DM), and organic matter digestibility, and the rate of liveweight gain. Addition of the surfactants SDS or alkanate 3SL3 to the diet of mulga-fed sheep did not improve N balance or digestion; however, apparent digestibility of P, and P and S balance, were significantly improved by SDS. Teric PE64, a compound structurally similar to PEG, significantly improved S balance, but not DM intake or N balance. For sheep consuming a predominantly mulga diet under paddock conditions, provision of PEG at a rate of 12 g/day significantly improved clean wool growth and liveweight gain compared with unsupplemented sheep, by 9% and 100%, respectively (0·809 v. 0·745 mg/cm2.day, and 44 v. 22 g/day). The studies demonstrated that although surfactants can affect mulga digestion, using PEG to precipitate CT is more effective to improve mulga digestion and animal production than the use of surfactants. However, the wool and liveweight production responses achieved with PEG were not sufficient to justify its wide-scale use for mulga-fed sheep. Consequently, alternative methods should be sought to reduce the negative effects of mulga CT on sheep production

A sustainable agricultural landscape for Australia: A review of interlacing carbon sequestration, biodiversity and salinity management in agroforestry systems

Transformation of the south-western Australian landscape from deep-rooted woody vegetation systems to shallow-rooted annual cropping systems has resulted in the severe loss of biodiversity and this loss has been exacerbated by rising ground waters that have mobilised stored salts causing extensive dry land salinity. Since the original plant communities were mostly perennial and deep rooted, the model for sustainable agriculture and landscape water management invariably includes deep rooted trees. Commercial forestry is however only economical in higher rainfall (>700 mm yr(-1)) areas whereas much of the area where biodiversity is threatened has lower rainfall (300-700 mm yr(-1)). Agroforestry may provide the opportunity to develop new agricultural landscapes that interlace ecosystem services such as carbon mitigation via carbon sequestration and biofuels, biodiversity restoration, watershed management while maintaining food production. Active markets are developing for some of these ecosystem services, however a lack of predictive metrics and the regulatory environment are impeding the adoption of several ecosystem services. Nonetheless, a clear opportunity exists for four major issues - the maintenance of food and fibre production, salinisation, biodiversity decline and climate change mitigation - to be managed at a meaningful scale and a new, sustainable agricultural landscape to be develope

Parallel encoding of focus and interrogative meaning in Mandarin intonation

Despite much research, disagreements abound regarding the detailed characteristics of question intonation in different languages or even in the same language. The present study investigates question intonation in Mandarin by also considering the role of focus that is frequently ignored in previous research. In experiment 1, native speakers of Mandarin produced statements, yes/no questions, particle questions, wh-questions, rhetorical questions and confirmation questions with narrow focus on the initial, medial or final word of the sentence, or on none of the words. Detailed F0 contour analyses showed that focus generated the same pitch range modification in questions as in statements, i.e., expanding the pitch range of the focused word, suppressing (compressing and lowering) that of the post-focus words, but leaving that of the pre-focus words largely unaffected. When the effects of focus (as well as other functions also potentially present) were controlled by subtracting statement F0 contours from those of the corresponding yes/no questions, the resulting difference curves resembled exponential or even double-exponential functions. Further F0 analyses also revealed an interaction between focus and interrogative meaning in the form of a boost to the pitch raising by the question starting from the focused word. Finally, subtle differences in the amount of pitch raising were also observed among different types of questions, especially at the sentencefinal position. Experiment 2 investigated whether listeners could detect both focus and question in the same utterance. Results showed that listeners could identify both in most cases, indicating that F0 variations related to the two functions could be simultaneously transmitted. Meanwhile, the lowest identification rates were found for neutral focus in questions and for statements with final focus. In both cases, the confusions seemed to arise from the competing F0 adjustments by interrogative meaning and focus at the sentence-final position. These findings are consistent with the functional view of intonation, according to which components of intonation are defined and organized by individual communicative functions that are independent of each other but are encoded in parallel