103 research outputs found

    Minimally Entangled Typical Thermal State Algorithms

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    We discuss a method based on sampling minimally entangled typical thermal states (METTS) that can simulate finite temperature quantum systems with a computational cost comparable to ground state DMRG. Detailed implementations of each step of the method are presented, along with efficient algorithms for working with matrix product states and matrix product operators. We furthermore explore how properties of METTS can reveal characteristic order and excitations of systems and discuss why METTS form an efficient basis for sampling. Finally, we explore the extent to which the average entanglement of a METTS ensemble is minimal.Comment: 18 pages, 14 figure

    Bovine Tuberculosis and Badger Culling in England: An Animal Rights-Based Analysis of Policy Options

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    Bovine tuberculosis (bovine TB) is an important and controversial animal health policy issue in England, which impacts humans, cattle and badgers. The government policy of badger culling has led to widespread opposition, in part due to the conclusions of a large field trial recommending against culling, and in part because badgers are a cherished wildlife species. Animal rights (AR) theorists argue that sentient nonhumans should be accorded fundamental rights against killing and suffering. In bovine TB policy, however, pro-culling actors claim that badgers must be culled to avoid the slaughter of cattle. The first part of the paper compares AR theories of Regan, Francione, Cochrane, Garner and Donaldson and Kymlicka in the context of wildlife species. The second part of the paper applies these AR theories to bovine TB and badger control. AR theories are applied to badger control policy options of (1) do nothing, (2) badger culling, and (3) badger vaccination. We conclude that AR theories are strongly opposed to badger culling. In general, culling is prohibited due to a badger’s right to life and its rights against suffering. The AR theories support a do-nothing, i.e. non-culling, non-vaccination approach to badger control. In the case of the AR theories of Regan and Francione, this is based on abolitionist positions with respect to farming. For Cochrane, Garner, and Donaldson and Kymlicka, the do-nothing policy option is preferred because badger vaccination causes a degree of suffering which generally is not for the individual’s benefit

    The AuScope geodetic VLBI array

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    The AuScope geodetic Very Long Baseline Interferometry array consists of three new 12-m radio telescopes and a correlation facility in Australia. The telescopes at Hobart (Tasmania), Katherine (Northern Territory) and Yarragadee (Western Australia) are co-located with other space geodetic techniques including Global Navigation Satellite Systems (GNSS) and gravity infrastructure, and in the case of Yarragadee, satellite laser ranging (SLR) and Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) facilities. The correlation facility is based in Perth (Western Australia). This new facility will make significant contributions to improving the densification of the International Celestial Reference Frame in the Southern Hemisphere, and subsequently enhance the International Terrestrial Reference Frame through the ability to detect and mitigate systematic error. This, combined with the simultaneous densification of the GNSS network across Australia, will enable the improved measurement of intraplate deformation across the Australian tectonic plate. In this paper, we present a description of this new infrastructure and present some initial results, including telescope performance measurements and positions of the telescopes in the International Terrestrial Reference Frame. We show that this array is already capable of achieving centimetre precision over typical long-baselines and that network and reference source systematic effects must be further improved to reach the ambitious goals of VLBI2010

    Bovine Tuberculosis Policy in England: Would a Virtuous Government Cull Mr Badger?

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    Bovine tuberculosis (bovine TB) is the most important animal health and welfare policy issue in Britain. Badgers are a wildlife reservoir of disease, although the eight-year Independent Scientific Group (ISG) Randomised Badger Culling Trial concluded with a recommendation against culling. The report advised government that bovine TB could be controlled, and ultimately eradicated, by cattle-based measures alone. Despite the ISG recommendation against culling, the farming and veterinary industries continued to lobby government for a badger cull. The 2005–2010 Labour government followed the ISG advice and decided against a cull. The 2010–2015 Coalition and the 2015-present Conservative governments have followed a badger culling policy. This paper investigates whether a virtuous government would cull badgers. It provides an overview of virtue theory in the context of government animal health and welfare policy. Bovine TB and badger control policy options are then analysed in the context of the virtues of justice, wisdom, integrity, loyalty, curiosity, trust, empathy, compassion and aesthetics. Justice is the first virtue of government, and badger culling is seriously problematic from a virtue perspective given that five badgers are culled per cow that avoids slaughter as a result. Analysis based on other virtues strongly suggests that government should not cull badgers. The paper concludes that a virtuous government would not cull badgers as part of policy to control bovine TB in cattle

    Discovery of a Sub-Parsec Radio Counterjet in the Nucleus of Centaurus A

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    A sub-parsec scale radio counterjet has been detected in the nucleus of the closest radio galaxy, Centaurus A (NGC 5128), with VLBI imaging at 2.3 and 8.4 GHz. This is one of the first detections of a VLBI counterjet and provides new constraints on the kinematics of the radio jets emerging from the nucleus of Cen A. A bright, compact core is seen at 8.4 GHz, along with a jet extending along P.A. 51 degrees. The core is completely absorbed at 2.3 GHz. Our images show a much wider gap between the base of the main jet and the counterjet at 2.3 GHz than at 8.4 GHz and also that the core has an extraordinarily inverted spectrum. These observations provide evidence that the innermost 0.4-0.8 pc of the source is seen through a disk or torus of ionized gas which is opaque at low frequencies due to free-free absorption.Comment: 3 pages, 2 postscript figures, scheduled for publication in August 1, 1996 issue of Ap.J. Letter

    Deriving Global OH Abundance and Atmospheric Lifetimes for Long-Lived Gases: A Search for CH 3 CCl 3 Alternatives

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    An accurate estimate of global hydroxyl radical (OH) abundance is important for projections of air quality, climate, and stratospheric ozone recovery. As the atmospheric mixing ratios of methyl chloroform (CH₃CCl₃) (MCF), the commonly used OH reference gas, approaches zero, it is important to find alternative approaches to infer atmospheric OH abundance and variability. The lack of global bottom‐up emission inventories is the primary obstacle in choosing a MCF alternative. We illustrate that global emissions of long‐lived trace gases can be inferred from their observed mixing ratio differences between the Northern Hemisphere (NH) and Southern Hemisphere (SH), given realistic estimates of their NH‐SH exchange time, the emission partitioning between the two hemispheres, and the NH versus SH OH abundance ratio. Using the observed long‐term trend and emissions derived from the measured hemispheric gradient, the combination of HFC‐32 (CH₂F₂), HFC‐134a (CH₂FCF₃, HFC‐152a (CH₃CHF₂), and HCFC‐22 (CHClF₂), instead of a single gas, will be useful as a MCF alternative to infer global and hemispheric OH abundance and trace gas lifetimes. The primary assumption on which this multispecies approach relies is that the OH lifetimes can be estimated by scaling the thermal reaction rates of a reference gas at 272 K on global and hemispheric scales. Thus, the derived hemispheric and global OH estimates are forced to reconcile the observed trends and gradient for all four compounds simultaneously. However, currently, observations of these gases from the surface networks do not provide more accurate OH abundance estimate than that from MCF

    Bovine Tuberculosis and Badger Culling in England: A Utilitarian Analysis of Policy Options

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    Bovine tuberculosis (bovine TB) is an important animal health policy issue in Britain, which impacts farmers, the public, domestic farmed cattle and the wild badger population. The Westminster government’s badger culling policy in England, which began in 2013, has caused considerable controversy. This is in part because the Independent Scientific Group advised against culling, based on the Randomised Badger Culling Trial. Those opposed to badger culling support more stringent cattle-based measures and the vaccination of badgers. This paper argues for ethical analysis of public policy options which impact sentient species. It provides a summary Animal Welfare Impact Assessment of (1) a do-nothing approach, (2) badger culling, and (3) badger vaccination. A utilitarian analysis is then applied to these policy options considering human wellbeing and animal welfare. The analysis compares a badger culling policy that achieves a 19% reduction in bovine TB incidence, a badger vaccination model achieving a 12.5% reduction, and a do-nothing approach. Policy options are assessed over 9 years and a longer timeframe, and uncertainty is considered. The analysis finds that non-culling approaches, particularly badger vaccination, result in greater total utility, compared to badger culling. Badger culling causes 30% reduction in the badger population in England as well as substantial harms due to the culling process. Culling is opposed by public opinion and is associated with considerable risks and uncertainty. In contrast, non-culling approaches, such as cattle-based measures and badger vaccination, are supported by public opinion and are not associated with such risks

    Bovine Tuberculosis and Badger Control in Britain: Science, Policy and Politics

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    Bovine tuberculosis (bovine TB) is the most economically important animal health policy issue in Britain. The problem of what to do about badgers has plagued successive governments since a dead badger was discovered with bovine TB in 1971. Successive Labour governments (1997–2010) oversaw the Randomised Badger Culling Trial (RBCT) from 1998 to 2006. Despite the RBCT recommendation against culling, the 2010–2015 Coalition government implemented pilot badger culls. This paper provides an account of the evolution of bovine TB and badger control policy, focusing on the 1997–2010 Labour, the 2010–2015 Coalition and the 2015-present Conservative governments. Interviews with bovine TB policy stakeholders supplement discussion of the development of bovine TB policy. The paper discusses the science and politics of bovine TB policy, in which there are different badger control policies in Westminster, Welsh and Scottish governments. Badger control is a highly polarised issue, and the Coalition and Conservative governments have been heavily criticised for a culling policy opposed by the independent scientific community. Recent governments have defended badger culling on the basis of veterinary advice and experience in countries such as New Zealand. The paper concludes with two key recommendations to inform controversial animal health and welfare policy issues such as bovine TB. First, mandatory Animal Welfare Impact Assessment provides objective data on the impacts of policy options on cows and badgers. Second, robust ethical analysis, conducted by independent experts using established moral frameworks, should be applied to animal health and welfare issues for the benefit of decision makers

    New genetic loci implicated in fasting glucose homeostasis and their impact on type 2 diabetes risk.

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    Levels of circulating glucose are tightly regulated. To identify new loci influencing glycemic traits, we performed meta-analyses of 21 genome-wide association studies informative for fasting glucose, fasting insulin and indices of beta-cell function (HOMA-B) and insulin resistance (HOMA-IR) in up to 46,186 nondiabetic participants. Follow-up of 25 loci in up to 76,558 additional subjects identified 16 loci associated with fasting glucose and HOMA-B and two loci associated with fasting insulin and HOMA-IR. These include nine loci newly associated with fasting glucose (in or near ADCY5, MADD, ADRA2A, CRY2, FADS1, GLIS3, SLC2A2, PROX1 and C2CD4B) and one influencing fasting insulin and HOMA-IR (near IGF1). We also demonstrated association of ADCY5, PROX1, GCK, GCKR and DGKB-TMEM195 with type 2 diabetes. Within these loci, likely biological candidate genes influence signal transduction, cell proliferation, development, glucose-sensing and circadian regulation. Our results demonstrate that genetic studies of glycemic traits can identify type 2 diabetes risk loci, as well as loci containing gene variants that are associated with a modest elevation in glucose levels but are not associated with overt diabetes
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