Open timelike curves violate Heisenberg's uncertainty principle

Toy models for quantum evolution in the presence of closed timelike curves (CTCs) have gained attention in the recent literature due to the strange effects they predict. The circuits that give rise to these effects appear quite abstract and contrived, as they require non-trivial interactions between the future and past which lead to infinitely recursive equations. We consider the special case in which there is no interaction inside the CTC, referred to as an open timelike curve (OTC), for which the only local effect is to increase the time elapsed by a clock carried by the system. Remarkably, circuits with access to OTCs are shown to violate Heisenberg's uncertainty principle, allowing perfect state discrimination and perfect cloning of coherent states. The model is extended to wave-packets and smoothly recovers standard quantum mechanics in an appropriate physical limit. The analogy with general relativistic time-dilation suggests that OTCs provide a novel alternative to existing proposals for the behaviour of quantum systems under gravity

A comparison of the yield, nutritional value and predicted production potential of different maize hybrids for silage production

The yield, nutritional value and production potential of silage made from twenty one maize hybrids was compared. The digestibility of organic matter and predicted intake, mean retention time and milk production potential were found to differ between hybrids (p < 0.05). Acid detergent fibre content could not be used to accurately predict the metabolizable energy content of silage. (South African Journal of Animal Science, 2000, 30(1): 18-21

Iterating ‘addiction’: Residential relocation and the spatio-temporal production of alcohol and other drug consumption patterns

Addiction is generally understood to be characterised by a persistent pattern of regular, heavy alcohol and other drug consumption. Current models of addiction tend to locate the causes of these patterns within the body or brain of the individual, sidelining relational and contextual factors. Where space and place are acknowledged as key factors contributing to consumption, they tend to be conceived of as static or fixed, which limits their ability to account for the fluid production and modulation of consumption patterns over time. In this article we query individualised and decontextualised understandings of the causes of consumption patterns through an analysis of accounts of residential relocation from interviews undertaken for a large research project on experiences of addiction in Australia. In conducting our analysis we conceptualise alcohol and other drug consumption patterns using Karen Barad's notions of intra-action and spatio-temporality, which allow for greater attention to be paid to the spatial and temporal dimensions of the material and social processes involved in generating consumption patterns. Drawing on 60 in-depth interviews conducted with people who self-identified as experiencing an alcohol and other drug addiction, dependence or habit, our analysis focuses on the ways in which participant accounts of moving enacted space and time as significant factors in how patterns of consumption were generated, disrupted and maintained. Our analysis explores how consumption patterns arose within highly localised relations, demonstrating the need for understandings of consumption patterns that acknowledge the indivisibility of space and time in their production. In concluding, we argue for a move away from static conceptions of place towards a more dynamic conception of spatio-temporality, and suggest the need to consider avenues for more effectively integrating place and time into strategies for generating preferred consumption patterns and initiating and sustaining change where desired

Causal Factors of Breeding Success and Frequency in Threatened Grassland Birds on the Ingula Nature Reserve, South Africa

The high-altitude grasslands covering the eastern escarpment of South Africa is one of the country’s most valuable habitats for biodiversity, livestock and water production. The habitat hosts several threatened bird species including endangered species such as the Rudd\u27s Lark (Heteromirafra ruddi) and Grey Crowned Crane (Balearica regulorum), and vulnerable species such as the Blue Crane (Grus paradisea), Wattled Crane (Bugeranus carunculatus), Southern Bald Ibis (Geronticus calvus), and Yellow-breasted Pipit (Anthus chloris). Avian research and monitoring have been ongoing within the recently declared Ingula Nature Reserve for more than 15 years as part of the activities of the Ingula Partnership - a partnership between BirdLife South Africa, Eskom Holdings SOC Ltd and the Middelpunt Wetland Trust - with the objective of effectively conserving birds and their habitat surrounding the Ingula Pumped Storage Scheme development. Avian monitoring on Ingula refocused in 2014 to confirm the presence of threatened species on site, followed by the determination of the breeding status of these species. An initiative was then launched to assess the breeding frequency and success of each identified species. Breeding monitoring for 13 out of the 24 occurring threatened species commenced in 2014 and was conducted for five consecutive seasons. Breeding success per season was measured in relation to the grassland management regime of that season (including both fire and grazing), as well as weather data, adjusting for dry and wet seasons. Results confirm that various grassland management regimes directly influenced the initiation of breeding activities and density of several of the species studied, while others’ breeding success and frequency were more dependent on macro-weather patterns (including climate change) and fire frequency and timing. These results have direct implications for the management of highland grasslands and associated species in the given region

The Kinetics of the Silver(i)-induced Oxidation of Chromium(iii) by Peroxodisulphate

Chromium(III) and chromium(VI) compounds play an important role in natural oxidation processes in terrestrial and atmospheric water. During the oxidation of SO2, peroxodisulphate is formed as an intermediate. In acidic and neutral solutions, peroxodisulphate oxidizes chromium(III) very slowly. This reaction rate is markedly enhanced by silver ions, resulting in a reaction rate that allows the reaction to be studied conveniently under laboratory conditions. The kinetics of the Cr(III)/Ag(I)/S2O82– reaction system were studied as a function of different Cr(III), Ag(I) and S2O82– concentrations, temperature and pressure. The formation of Cr(VI) was observed as a first-order process at high [Cr(III)] and as a zero-order process at low [Cr(III)].Aninduction period was observed in both cases. For the first-order process, reaction rates were found to be independent of [Cr(III)], linearly dependent on [Ag+] and independent of [S2O82–]. The activation enthalpy (ΔH≠) was calculated as 56 ± 5 kJ mol–1, the activation entropy (ΔS≠) as –136 ± 16 J K–1 mol–1 and the activation volume as –5.8 ± 0.7 cm3 mol–1. At low [Cr(III)], the reaction rate was independent of [Cr(III)], linearly dependent on [S2O82–] and non-linearly dependent on [Ag+], reaching a limiting value at high [Ag+]. The activation enthalpy (ΔH≠) was calculated as 61±5kJmol–1, the activation entropy (ΔS≠) as –119±15 J K–1 mol–1 and the activation volume as –1.7±0.1 cm3 mol–1. A mechanism involving the reversible formation of a silver-peroxodisulphate complex that decomposes into oxidizing intermediates is proposed. The empirical observations can be adequately described by this mechanism.Keywords: Chromium(III), peroxodisulphate, oxidation, silver

Nitro­furan­toin methanol monosolvate

The anti­biotic nitro­furan­toin {systematic name: (E)-1-[(5-nitro-2-fur­yl)methyl­idene­amino]­imidazolidine-2,4-dione} crys­tallizes as a methanol monosolvate, C8H6N4O5·CH4O. The nitro­furan­toin mol­ecule adopts a nearly planar conformation (r.m.s. deviation = 0.0344 Å). Hydrogen bonds involve the co-operative N—H⋯O—H⋯O heterosynthons between the cyclic imide of nitro­furan­toin and methanol O—H groups. There are also C—H⋯O hydrogen bonds involving the nitro­furan­toin mol­ecules which support the key hydrogen-bonding synthon. The overall crystal packing is further assisted by weak C—H⋯O inter­actions, giving a herringbone pattern

Gene synthesis by integrated polymerase chain assembly and PCR amplification using a high-speed thermocycler

Polymerase chain assembly (PCA) is a technique used to synthesize genes ranging from a few hundred base pairs to many kilobase pairs in length. In traditional PCA, equimolar concentrations of single stranded DNA oligonucleotides are repeatedly hybridized and extended by a polymerase enzyme into longer dsDNA constructs, with relatively few full-length sequences being assembled. Thus, traditional PCA is followed by a second primer-mediated PCR reaction to amplify the desired full-length sequence to useful, detectable quantities. Integration of assembly and primer-mediated amplification steps into a single reaction using a high-speed thermocycler is shown to produce similar results. For the integrated technique, the effects of oligo concentration, primer concentration, and number of oligonucleotides are explored. The technique is successfully demonstrated for the synthesis of two genes encoding EPCR-1 (653 bp) and pUC19 β-lactamase (929 bp) in under 20 min. However, rapid integrated PCA–PCR was found to be problematic when attempted with the TM-1 gene (1509 bp). Partial oligonucleotide sets of TM-1 could be assembled and amplified simultaneously, indicating that the technique may be limited to a maximum number of oligonucleotides due to competitive annealing and competition for primers

Gene synthesis by integrated polymerase chain assembly and PCR amplification using a high-speed thermocycler

Polymerase chain assembly (PCA) is a technique used to synthesize genes ranging from a few hundred base pairs to many kilobase pairs in length. In traditional PCA, equimolar concentrations of single stranded DNA oligonucleotides are repeatedly hybridized and extended by a polymerase enzyme into longer dsDNA constructs, with relatively few full-length sequences being assembled. Thus, traditional PCA is followed by a second primer-mediated PCR reaction to amplify the desired full-length sequence to useful, detectable quantities. Integration of assembly and primer-mediated amplification steps into a single reaction using a high-speed thermocycler is shown to produce similar results. For the integrated technique, the effects of oligo concentration, primer concentration, and number of oligonucleotides are explored. The technique is successfully demonstrated for the synthesis of two genes encoding EPCR-1 (653 bp) and pUC19 β-lactamase (929 bp) in under 20 min. However, rapid integrated PCA–PCR was found to be problematic when attempted with the TM-1 gene (1509 bp). Partial oligonucleotide sets of TM-1 could be assembled and amplified simultaneously, indicating that the technique may be limited to a maximum number of oligonucleotides due to competitive annealing and competition for primers

Addiction stigma and the biopolitics of liberal modernity: A qualitative analysis

Definitions of addiction have never been more hotly contested. The advance of neuroscientific accounts has not only placed into public awareness a highly controversial explanatory approach, it has also shed new light on the absence of agreement among the many experts who contest it. Proponents argue that calling addiction a 'brain disease' is important because it is destigmatising. Many critics of the neuroscientific approach also agree on this point. Considered from the point of view of the sociology of health and illness, the idea that labelling something a disease will alleviate stigma is a surprising one. Disease, as demonstrated in that field of research, is routinely stigmatised. In this article we take up the issue of stigma as it plays out in relation to addiction, seeking to clarify and challenge the claims made about the progress associated with disease models. To do so, we draw on Erving Goffman's classic work on stigma, reconsidering it in light of more recent, process oriented, theoretical resources, and posing stigmatisation as a performative biopolitical process. Analysing recently collected interviews conducted with 60 people in Australia who consider themselves to have an alcohol or other drug addiction, dependence or habit, we explore their accounts of stigma, finding experiences of stigma to be common, multiple and strikingly diverse. We argue that by treating stigma as politically productive - as a contingent biopolitically performative process rather than as a stable marker of some kind of anterior difference - we can better understand what it achieves. This allows us to consider not simply how the 'disease' of addiction can be destigmatised, or even whether the 'diseasing' of addiction is itself stigmatising (although this would seem a key question), but whether the very problematisation of 'addiction' in the first place constitutes a stigma process