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Concerns over livestock production practices have resulted in increased consumer preferences for certified products. Australian beef buyers' survey data revealed the preferences of consumers who would buy differentiated beef based on animal welfare, safety, health, or environmental -friendly considerations. Female respondents are more likely to buy certified animal welfare products. Buyers with children, and those who value branded beef, are more likely to buy products differentiated by a bundle of credence attributes. Given that Australian beef consumers eat similar amounts, there are opportunities for differentiating beef products according to credence attributes and offering them in a range of retailers. [ABSTRACT FROM AUTHOR]

Accepting that increased climate variability will require that farmers make significant changes to their farm systems, we can see that maintaining flexibility is an important coping strategy. Using general systems theory, we offer a conceptual model for describing the tactical and strategic flexibility of farm systems to reveal the sensitivity of farm systems to variable critical inputs. The model is used to classify farm systems as rigid, robust, or elastic on the basis of two factors, the capacity of the farmer to reduce reliance on critical inputs by altering the following: (i) the use of critical inputs and (ii) farm output. The different production emphasis for the different types of systems has implications for how these farmers are able to respond to increased variability and on public policies that may support viable farm businesses in the face of increased variability. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Aims Real-time MRI creates images with superb tissue contrast that may enable radiation-free catheterization. Simple procedures are the first step towards novel interventional procedures. We aim to perform comprehensive transfemoral diagnostic right heart catheterization in an unselected cohort of patients entirely using MRI guidance. Methods and results We performed X-ray and MRI-guided transfemoral right heart catheterization in consecutive patients undergoing clinical cardiac catheterization. We sampled both cavae and both pulmonary arteries. We compared success rate, time to perform key steps, and catheter visibility among X-ray and MRI procedures using air-filled or gadolinium-filled balloon-tipped catheters. Sixteen subjects (four with shunt, nine with coronary artery disease, three with other) underwent paired X-ray and MRI catheterization. Complete guidewire-free catheterization was possible in 15 of 16 under both. MRI using gadolinium-filled balloons was at least as successful as X-ray in all procedure steps, more successful than MRI using air-filled balloons, and better than both in entering the left pulmonary artery. Total catheterization time and individual procedure steps required approximately the same amount of time irrespective of image guidance modality. Catheter conspicuity was best under X-ray and next-best using gadolinium-filled MRI balloons. Conclusion In this early experience, comprehensive transfemoral right heart catheterization appears feasible using only MRI for imaging guidance. Gadolinium-filled balloon catheters were more conspicuous than air-filled ones. Further workflow and device enhancement are necessary for clinical adoption. [ABSTRACT FROM PUBLISHER]

Background We aim to deliver large appliances into the left ventricle through the right ventricle and across the interventricular septum. This transthoracic access route exploits immediate recoil of the septum, and lower transmyocardial pressure gradient across the right versus left ventricular free wall. The route may enhance safety and allow subxiphoid rather than intercostal traversal. Methods The entire procedure was performed under real-time CMR guidance. An “active” CMR needle crossed the chest, right ventricular free wall, and then the interventricular septum to deliver a guidewire then used to deliver an 18Fr introducer. Afterwards, the right ventricular free wall was closed with a nitinol occluder. Immediate closure and late healing of the unrepaired septum and free wall were assessed by oximetry, angiography, CMR, and necropsy up to four weeks afterwards. Results The procedure was successful in 9 of 11 pigs. One failed because of refractory ventricular fibrillation upon needle entry, and the other because of inadequate guidewire support. In all ten attempts, the right ventricular free wall was closed without hemopericardium. There was neither immediate nor late shunt on oximetry, X-ray angiography, or CMR. The interventricular septal tract fibrosed completely. Transventricular trajectories planned on human CT scans suggest comparable intracavitary working space and less acute entry angles than a conventional atrial transseptal approach. Conclusion Large closed-chest access ports can be introduced across the right ventricular free wall and interventricular septum into the left ventricle. The septum recoils immediately and heals completely without repair. A nitinol occluder immediately seals the right ventricular wall. The entry angle is more favorable to introduce, for example, prosthetic mitral valves than a conventional atrial transseptal approach. [ABSTRACT FROM AUTHOR]

Background: Needle access or drainage of pericardial effusion, especially when small, entails risk of bystander tissue injury or operator uncertainty about proposed trajectories. Cardiovascular magnetic resonance (CMR) might allow enhanced imaging guidance. Methods and results: We used real-time CMR to guide subxiphoid pericardial access in naïve swine using commercial 18G titanium puncture needles, which were exchanged for pericardial catheters. To test the value of CMR needle pericardiocentesis, we also created intentional pericardial effusions of a range of volumes, via a separate transvenous-transatrial catheter. We performed these procedures in 12 animals. Pericardiocentesis was performed in 2:47 ± 1:43 minutes; pericardial access was performed in 1:40 ± 4:34 minutes. The procedure was successful in all animals. Moderate and large effusions required only one needle pass. There were no complications, including pleural, hepatic or myocardial transit. Conclusions: CMR guided pericardiocentesis is attractive because the large field of view and soft tissue imaging depict global anatomic context in arbitrary planes, and allow the operator to plan trajectories that limit inadvertent bystander tissue injury. More important, CMR provides continuous visualization of the needle and target throughout the procedure. Using even passive needle devices, CMR enabled rapid pericardial needle access and drainage. We believe this experience supports clinical testing of real-time CMR guided needle access or drainage of the pericardial space. We suspect this would be especially helpful in "difficult" pericardial access, for example, in distorted thoracic anatomy or loculated effusion. [ABSTRACT FROM AUTHOR]

The regional distribution of skeletal muscle blood flow was measured during postischemic reactive hyperemia using Gd-DTPA contrast-enhanced (CE) MRI. The release of an occlusive thigh cuff was used to deliver a step-input of contrast concentration that was coincident with the onset of reactive hyperemia. A first-order tracer kinetic equation was used to estimate the unidirectional influx constant, K i (ml/100 g/min), and the distribution volume of Gd-DTPA in the tissue, v e, from T1-weighted images acquired with saturation recovery (SR) steady-state free precession (SSFP) and spoiled gradient-echo (SPGR) protocols. The capillary permeability surface (PS) area increased significantly during reactive hyperemia, which facilitated rapid extraction of Gd-DTPA during the first pass. Regional muscle group studies from 11 normal volunteers yielded blood flow ( K i) values of 108.3 ± 34.1 ml/100 g/min in the gastrocnemius, 184.3 ± 41.3 ml/100 g/min in the soleus, and 122.4 ± 34.4 ml/100 g/min in the tibialis anterior. The distribution volumes ( v e) in the corresponding muscle groups were respectively 8.3% ± 2.1%, 9.3% ± 1.9%, and 7.9% ± 1.8% from the kinetic model, and 8.8% ± 2.4%, 9.1% ± 1.9%, and 7.2% ± 1.4% from tissue relaxometry studies. Bulk blood flow studies in the same volunteers using phase-contrast velocimetry (popliteal artery) yielded significantly lower flow values, but with a correlation coefficient R2 = 0.62 and P = 0.004. Magn Reson Med 54:289-298, 2005. Published 2005 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Glutamate dehydrogenase (GDH) isoenzymes were purified from control, and ribonucleoside triphosphate (NTP)-treated peanut seedlings. GDH purification was by preparative-scale, free solution isoelectric focusing, followed by native PAGE, and the cryoelectrophoretic elution of the isoenzymes from the gel. SDS-PAGE of the purified GDH isoenzymes, followed by either silver staining of the gel, or western analysis using anti-GDH antibody, gave identical GDH polypeptide (a, α, and b) bands, thus, confirming the purity of the isoenzymes. The substrate specificities in the aminating activity of the GDH isoenzymes, or disaggregated polypeptides were determined by photometry, but the substrate specificities in the RNA synthesis activity were determined in cocktails containing 0.06–0.8 mM of each of UTP, ATP, GTP, and CTP, 0–100.0 mM NH4Cl, 0–50.0 mM α-ketoglutaratr (α-KG), 0–0.2 mM NADH, 0–10.0 mM CaCl2 5 units of DNase 1, antibiotics, and ∼5 µg pure GDH isoenzymes or polypeptides at pH 8.0, and overnight at 16°C. The GDH polypeptides were active only in amination reaction, but the GDH isoenzymes were active in both amination and RNA synthesis. Whereas, NADH, NH4Cl and α-KG served as the substrates for the amination reaction, and as modulators in the RNA synthetic reaction, ATP, GTP, UTP, and CTP served as substrates for the isoenzymes in RNA synthesis reaction. The product RNA was up to 2 µg µg-1 GDH, and consisted of RNA species in the size ranges of 26, 16, and 5 S rRNAs. DNAse 1 in the assay cocktail ruled out transcription as the mechanism of the RNA synthesis. Addition of [α-32P] NTP led to the production of labeled RNA, thus confirming the specificity of NTPs as substrates, and that the RNA was not pre-existing in the reaction cocktail. [ABSTRACT FROM AUTHOR]

The article reports on doctor Victor Wright, a 2006 Australian Agricultural and Resource Economics Society Inc. (AARES) distinguished fellow. He has worked at the interface between agricultural marketing and business marketing, farm management, and general management, at the University of New England.