376 research outputs found
Genotypic Effects on Condensed Tannins in the Leucaena Genus
One hundred and eighteen accessions of the Leucaena genus were assayed for extractable and bound condensed tannins (CT). Leucaena taxa varied from low or no CT (0-1%) to extremely high levels (\u3e15%). There was considerable intraspecific variation in CT within key taxa. The proportion of bound tannin decreased with increasing total CT content
Leucaena in Northern Australia: A Forage Tree Legume Success Story
Leucaena leucocephala (leucaena) is a long-lived, perennial forage tree legume of very high nutritive value for ruminant production. In northern Australia, leucaena is direct seeded into hedgerows 5-10m apart, with grass species such as buffel grass (Cenchrus ciliaris) planted in the inter-row to form a highly productive and sustainable grass-legume pasture that cattle graze directly. It generally is grown on deep, fertile soils in sub-humid environments with average rainfall of 600-800mm/year. Steer gains of 275-300kg/head per year are achieved, with short-term daily gains over the main growing season \u3e 1kg/head. Being very deep-rooted, leucaena exploits moisture beyond the reach of grasses and remains productive well into the dry season. Once established, leucaena-grass pastures remain productive for \u3e 40 years
Toxicity in Beef Cattle Grazing \u3cem\u3eLeucaena leucocephala\u3c/em\u3e in Queensland, Australia
Improved pastures based on the leguminous shrub Leucaena leucocephala (leucaena) are the most productive, profitable and sustainable for beef cattle production in northern Australia. Leucaena forage contains the toxic, non-protein amino acid mimosine, which is rapidly converted to 3-hydroxy-4(1H)-pyridone (DHP) upon ingestion by grazing cattle. This is a potent goitrogen and appetite suppressant. Animals suffering severe DHP toxicity exhibit distinctive symptoms (e.g. hair loss, excessive salivation, goitre and weight loss), while subclinical DHP toxicity can suppress live weight gain by 30-50% without producing any obvious symptoms. Prior to the discovery and introduction of the DHP-degrading rumen bacteria Synergistes jonesii into Australia in 1982, DHP toxicity severely limited animal performance from leucaena pastures and was a major impediment to adoption. Initial rumen inoculation of cattle in Australia with S. jonesii successfully protected them against DHP toxicity and the bacterium appeared to be easily and rapidly transmitted between grazing animals. Consequently many scientists and graziers believed that a single inoculation of a herd with S. jonesii, combined with simple ongoing herd management, was sufficient to overcome the problem of DHP toxicity. However, during the 2003 drought there were several reports of severe leucaena toxicity (including animal deaths) in cattle grazing leucaena in Queensland. Toxicity was evident even in herds that had followed recommended control measures. Preliminary results are presented of a study, designed to ascertain the prevalence and possible causes of leucaena toxicity in Queensland cattle herds. Meat and Livestock Australia Limited funded this research (NBP.340)
Selection of Psyllid-Resistant Forage Varieties from an Inter-Specific Breeding Program of \u3cem\u3eLeucaena leucocephala\u3c/em\u3e with \u3cem\u3eL. pallida\u3c/em\u3e
Leucaena (Leucaena leucocephala) pastures for beef cattle production are productive and sustainable; however, susceptibility to the psyllid insect (Heteropsylla cubana) has limited expansion of current commercial cultivars into more humid areas (\u3e 800 mm/yr) (Shelton and Dalzell 2007). Psyllids can also cause intermittent damage in lower rainfall regions during humid periods. The psyllid, which arrived in Australia in 1986, is a leaf-sucking insect specific to the Leucaena genus, feeding on the growing tips of susceptible cultivars (Bray 1994). Psyllid damage can reduce production by as much as 50-70% in humid regions and 20-50% in subhumid environments (Bray 1994; Mullen and Shelton 2003). Work on psyllid resistance in the Leucaena genus through the 1990s showed that several Leucaena species, including the tetraploid L. pallida, had good levels of resistance (Mullen et al. 2003).
A breeding program to develop psyllid-resistant varieties began in 2002 at The University of Queensland (UQ) based on the F1 inter-specific hybrids between L. leucocephala and L. pallida (known as âKX2â), developed at the University of Hawaii (Brewbaker 2008). Between 2002 and 2005, UQ initiated a program of recurrent selection in an attempt to produce stable outcrossed KX2-derived lines but inbreeding depression for yield and poor forage quality led to a change in the breeding strategy, and a backcrossing program was implemented between 2005 and 2008. Two cycles of backcrossing to elite L. leucocephala ssp. glabrata material were completed followed by 2 cycles of progeny testing and selection for self-compatibility to achieve stability and uniformity (2009 - 2012). Forty elite psyllid-resistant lines were then evaluated to identify the most suitable lines for release to industry. This paper describes the results of these trials
Geomagnetically Induced Current Modeling in New Zealand: Extreme Storm analysis using multiple disturbance scenarios and industry provided hazard magnitudes
Geomagnetically induced currents (GICs) are induced in electrical power transmission networks during geomagnetic disturbances. Understanding the magnitude and duration of the GIC expected during worst-case extreme storm scenarios is vital to estimate potential damages and disruptions to power networks. In this study we utilize the magnetic field waveforms measured during three large geomagnetic storms and scale them to expected worst case extreme storm magnitudes. Multiple methods are used to simulate the varying magnitude of the magnetic field across the different latitudes of New Zealand. Modeled GIC is produced for nine extreme storm scenarios, each covering 1-1.5 days in duration. Our industry partners, Transpower New Zealand Ltd provided GIC magnitude and duration levels which represent a risk to their transformers. Using these thresholds various extreme storm scenarios predict between 44 and 115 New Zealand transformers (13-35%) are at risk of damaging levels of GIC. The transformers at risk are largely independent of the extreme storm time-variations, but depend more on the latitude variation scenario. We show that these at-risk transformers are not localized to any specific region of New Zealand but extend across all regions and include most of the major population centers. A peak mean absolute GIC over a 60-minute window of 920-2210 A and an instantaneous one-minute time resolution maximum GIC of 1590-4920 A occurs for a worst-case extreme storm scenario. We believe this is one of the first studies to combine a reasonable worst-case extreme geomagnetic storm with validated GIC modeling and industry-provided GIC risk thresholds
End-to-end resource analysis for quantum interior point methods and portfolio optimization
We study quantum interior point methods (QIPMs) for second-order cone
programming (SOCP), guided by the example use case of portfolio optimization
(PO). We provide a complete quantum circuit-level description of the algorithm
from problem input to problem output, making several improvements to the
implementation of the QIPM. We report the number of logical qubits and the
quantity/depth of non-Clifford T-gates needed to run the algorithm, including
constant factors. The resource counts we find depend on instance-specific
parameters, such as the condition number of certain linear systems within the
problem. To determine the size of these parameters, we perform numerical
simulations of small PO instances, which lead to concrete resource estimates
for the PO use case. Our numerical results do not probe large enough instance
sizes to make conclusive statements about the asymptotic scaling of the
algorithm. However, already at small instance sizes, our analysis suggests
that, due primarily to large constant pre-factors, poorly conditioned linear
systems, and a fundamental reliance on costly quantum state tomography,
fundamental improvements to the QIPM are required for it to lead to practical
quantum advantage.Comment: 38 pages, 15 figure
The Power of Environmental Observatories for Advancing Multidisciplinary Research, Outreach, and Decision Support: The Case of the Minnesota River Basin
An edited version of this paper was published by AGU. Copyright 2019 American Geophysical Union.Observatoryâscale data collection efforts allow unprecedented opportunities for integrative, multidisciplinary investigations in large, complex watersheds, which can affect management decisions and policy. Through the National Science Foundationâfunded REACH (REsilience under Accelerated CHange) project, in collaboration with the Intensively Managed LandscapesâCritical Zone Observatory, we have collected a series of multidisciplinary data sets throughout the Minnesota River Basin in southâcentral Minnesota, USA, a 43,400âkm2 tributary to the Upper Mississippi River. Postglacial incision within the Minnesota River valley created an erosional landscape highly responsive to hydrologic change, allowing for transdisciplinary research into the complex cascade of environmental changes that occur due to hydrology and land use alterations from intensive agricultural management and climate change. Data sets collected include water chemistry and biogeochemical data, geochemical fingerprinting of major sediment sources, highâresolution monitoring of river bluff erosion, and repeat channel crossâsectional and bathymetry data following major floods. The data collection efforts led to development of a series of integrative reduced complexity models that provide deeper insight into how water, sediment, and nutrients route and transform through a large channel network and respond to change. These models represent the culmination of efforts to integrate interdisciplinary data sets and science to gain new insights into watershedâscale processes in order to advance management and decision making. The purpose of this paper is to present a synthesis of the data sets and models, disseminate them to the community for further research, and identify mechanisms used to expand the temporal and spatial extent of shortâterm observatoryâscale data collection efforts
The Power of Environmental Observatories for Advancing Multidisciplinary Research, Outreach, and Decision Support: The Case of the Minnesota River Basin
Observatoryâscale data collection efforts allow unprecedented opportunities for integrative, multidisciplinary investigations in large, complex watersheds, which can affect management decisions and policy. Through the National Science Foundationâfunded REACH (REsilience under Accelerated CHange) project, in collaboration with the Intensively Managed LandscapesâCritical Zone Observatory, we have collected a series of multidisciplinary data sets throughout the Minnesota River Basin in southâcentral Minnesota, USA, a 43,400âkm2 tributary to the Upper Mississippi River. Postglacial incision within the Minnesota River valley created an erosional landscape highly responsive to hydrologic change, allowing for transdisciplinary research into the complex cascade of environmental changes that occur due to hydrology and land use alterations from intensive agricultural management and climate change. Data sets collected include water chemistry and biogeochemical data, geochemical fingerprinting of major sediment sources, highâresolution monitoring of river bluff erosion, and repeat channel crossâsectional and bathymetry data following major floods. The data collection efforts led to development of a series of integrative reduced complexity models that provide deeper insight into how water, sediment, and nutrients route and transform through a large channel network and respond to change. These models represent the culmination of efforts to integrate interdisciplinary data sets and science to gain new insights into watershedâscale processes in order to advance management and decision making. The purpose of this paper is to present a synthesis of the data sets and models, disseminate them to the community for further research, and identify mechanisms used to expand the temporal and spatial extent of shortâterm observatoryâscale data collection efforts
Animal welfare impacts of badger culling operations
We are writing to express our extreme concern following recent media coverage1, 2 relating to the methodology being used by contractors to kill badgers under licence, as part of the governmentâs policy to control bovine TB in cattle.
The coverage relates to the shooting of badgers that have been captured in live traps. Covert video footage (https://bit.ly/2Eud1iR ) from Cumbria shows a trapped badger being shot with a firearm at close range, following which it appears to take close to a minute to stop moving. The contractor clearly observes the animal during this time but makes no attempt to expedite the death of the badger and prevent further suffering, as required by the current Natural England best practice guide which states: âImmediately after shooting, the animal should be checked to ensure it is dead, and if there is any doubt, a second shot must be taken as soon as possible.â3 The conversation between the contractor and his companion also suggests they were considering moving the badger to another site before finally bagging the carcase, again breaching the best practice guide.
While the footage only relates to the experience of a single badger, and while the degree to which the badger was conscious in the period immediately following the shot is unclear, we can by no means be certain that the badger did not suffer. It also raises serious questions about the training, competence and behaviour of contractors, in relation to both badger welfare, and biosecurity. This adds to existing concerns relating to the humaneness of âcontrolled shootingâ (targeting free-roaming badgers with rifles), which continues to be a permitted method under culling licences, in spite of the reservations expressed by both the government-commissioned Independent Expert Panel in its 2014 report,4 and the BVA, which concluded in 2015 that it âcan no longer support the continued use of controlled shooting as part of the badger control policyâ.5 (However, it has since continued to support the issuing of licences which permit the method). The BVA has consistently indicated its support for what it calls the âtried and testedâ method of trapping and shooting, but has thus far failed to provide comprehensive and robust evidence for the humaneness of this method.
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Natural England reported that its monitors observed 74 (just over 0.6 per cent) of controlled shooting events for accuracy and humaneness
During 2017, almost 20,000 badgers were killed under licence across 19 cull zones, around 60 per cent of which were killed by controlled shooting, the remainder being trapped and shot.6 Natural England reported that its monitors observed 74 (just over 0.6 per cent) of controlled shooting events for accuracy and humaneness. No information has been provided on the extent to which trapping and shooting activities were monitored. This raises serious concerns about the extent of suffering that might be experienced by very large numbers of animals, for which contractors are not being held to account.
If contractors reach their maximum culling targets set by Natural England for 2018, as many as 41,000 additional badgers could be killed.7 The extent to which these animals will suffer is once again being left in the hands of contractors, with woefully inadequate oversight, and in the face of anecdotal evidence of breaches of best practice guidance. This situation is clearly unacceptable from an animal welfare perspective and it is our view that by endorsing the policy, the BVA is contradicting the principles contained within its own animal welfare strategy.8
We therefore urge the BVA to withdraw its support for any further licensed badger culling, and the RCVS to make it clear that any veterinarian who provides support for culling activities that result in unnecessary and avoidable animal suffering could face disciplinary proceedings. The veterinary profession has no business supporting this licensed mass killing with all its inherent negative welfare and biosecurity implications, and for which the disease control benefits are, at best, extremely uncertain.
We believe the continued support for the culls by veterinary bodies in the face of poor evidence for its efficacy damages the credibility of the profession, and that same support in the face of potential animal suffering on a large scale undermines its reputation.
We stand ready to discuss these issues in more detail
Tackling bovine TB
On 18 December Defra revealed that during 2018, 32,601 badgers were killed, bringing the total number slaughtered under licence since 2013 to almost 67,000.1
âEffectivenessâ claims relate not to the impact on cattle TB, but rather to the ability of the contracted shooters to kill sufficient badgers to satisfy their licence requirements, which they can hardly fail to reach given that target numbers are âadjustedâ by Natural England part-way through the culls according to the contractorsâ progress.
Sixty per cent of the badgers have been killed by âcontrolled shootingâ, a method rejected by both the governmentâs Independent Expert Panel2 and the BVA3 because of animal welfare concerns. During 2018 Natural England directly monitored just 89 (0.43 per cent) of controlled shooting events.
It is deplorable that the chief veterinary officer (CVO) continues to support the roll-out of a policy that permits controlled shooting, when veterinary organisations have condemned the method on animal welfare grounds. It is particularly concerning that the CVO appears to have deflected responsibility for humaneness to Natural Englandâs chief scientist who, as far as we are aware, has no background in animal welfare science.
It is also unacceptable for government to attribute reductions in herd bovine TB (bTB) incidents over the first four years of culling in the original âpilotâ cull zones to its badger culling policy.4 Independent analysis of this and more recent data from the Gloucestershire pilot cull zone5 indicate that new herd incidence is rising sharply, with 22 herd breakdowns in the 12 months to September 2017 (an increase of 29.4 per cent when compared to the 17 breakdowns reported by APHA for the previous 12 months). Analysis of the 2018 figures indicates that both incidence and prevalence are now rising even faster, with a further 24 herd breakdowns occurring between 1 January and 5 December 2018.
To date, the government and its officials cite data that are two years out of date, but have declined to comment on this emerging evidence that, far from resulting in a substantial disease control benefit, badger culls may be leading to a sharp increase in bTB in cattle.
Natural Englandâs chief scientist and the UKâs CVO continue to endorse a failing and inhumane policy, bringing their offices into serious disrepute. We urge them, and the BVA, to reconsider their support for further badger culling, and instead focus on the actual cause of bTBâs epidemic spread â a cattle skin test with a sensitivity of only 50 per cent,6,7 and the ongoing problems associated with cattle movements and on-farm biosecurity
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