6,769 research outputs found

    Microbial Similarity between Students in a Common Dormitory Environment Reveals the Forensic Potential of Individual Microbial Signatures.

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    The microbiota of the built environment is an amalgamation of both human and environmental sources. While human sources have been examined within single-family households or in public environments, it is unclear what effect a large number of cohabitating people have on the microbial communities of their shared environment. We sampled the public and private spaces of a college dormitory, disentangling individual microbial signatures and their impact on the microbiota of common spaces. We compared multiple methods for marker gene sequence clustering and found that minimum entropy decomposition (MED) was best able to distinguish between the microbial signatures of different individuals and was able to uncover more discriminative taxa across all taxonomic groups. Further, weighted UniFrac- and random forest-based graph analyses uncovered two distinct spheres of hand- or shoe-associated samples. Using graph-based clustering, we identified spheres of interaction and found that connection between these clusters was enriched for hands, implicating them as a primary means of transmission. In contrast, shoe-associated samples were found to be freely interacting, with individual shoes more connected to each other than to the floors they interact with. Individual interactions were highly dynamic, with groups of samples originating from individuals clustering freely with samples from other individuals, while all floor and shoe samples consistently clustered together.IMPORTANCE Humans leave behind a microbial trail, regardless of intention. This may allow for the identification of individuals based on the "microbial signatures" they shed in built environments. In a shared living environment, these trails intersect, and through interaction with common surfaces may become homogenized, potentially confounding our ability to link individuals to their associated microbiota. We sought to understand the factors that influence the mixing of individual signatures and how best to process sequencing data to best tease apart these signatures

    Poor choice? Smith, Hayek and the moral economy of food consumption

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    This paper explores the moral economy of food in the United Kingdom via discourses on food bank usage and obesity. It argues that both of these markers of malnutrition were interpreted under the Conservative-led governments of David Cameron (2010–2016) as failings of personal responsibility and identified primarily with the working class, advancing the assumption that poor people make poor choices. Based on a critique of this account, our wider contribution is two-fold. First, we identify the Hayekian lineage of the discourse of personal responsibility, highlighting its utility in facilitating a form of neoliberal market consent through its insistence on self-reliance. Second, we stake out an alternative to this conceptualization through a discussion of Adam Smith’s notion of self-command, which we call interpersonal responsibility

    Faddists, enthusiasts and Canadian divas: broadcasting quotas and the supply response

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    This paper constructs a model of the recorded music market to investigate the consequences of local content requirements in broadcasting for the "internationalization" of domestic music. It models the entry decisions of bands, the contracting decisions of record companies, the airplay decisions of radio stations and the radio listening and recording purchasing decisions of consumers. The paper shows that a local content quota leads, perversely, to the increased internationalization of domestic music. A quota that also requires increased broadcasting of "new" music yields an additional welfare loss but does nothing to a record company's incentives to sign up new bands

    Once Upon a Time

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    This paper is a short reflection on exposing myself to a variety of different media, (books, comic books, and television shows), that contains concepts on time travel. With this exposure, I will then attempt to draw my own comic book with time travel in it

    Online Tribes and Digital Authority:What Can Social Theory Bring to Digital Archaeology?

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    From early discussions of the disruptive potential of computer technologies for archaeological applications, to the present era of digital archaeology as the technical underpinning of modern archaeological practice, we have continued to debate the potential impacts of digital communication and digital capture and storage on our knowledge, profession and communications. The increased use of digital tools and methods for archaeological research and dissemination, as well as what Roosevelt (2015) has referred to as the shift to the digital paradigm within archaeological practice, leads us to suggest that the impact of this paradigm shift requires careful and critical examination. This article will examine the edges of the disciplines of archaeology and sociology, where we aim to advance our understanding of the relationship between digital technologies and archaeological knowledge from a uniquely social perspective, using the theoretical approaches of both classic and modern sociologists. The application of this lens of sociology to digital archaeology equips us to understand how archaeology and archaeological practice is situated in a social world, which is especially relevant in the Global West, where digital technology is ubiquitous. Through a critical consideration of the complexity of use of digital technologies within digital archaeology, we can begin to shift our focus away from the character and method of tools and workflow, to the background of intellectual power and influence

    Resolution of Key Roles for the Distal Pocket Histidine in Cytochrome c Nitrite Reductases

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    Cytochrome c nitrite reductases perform a key step in the biogeochemical N-cycle by catalyzing the six-electron reduction of nitrite to ammonium. These multi-heme cytochromes contain a number of His/His ligated c-hemes for electron transfer and a structurally differentiated heme that provides the catalytic center. The catalytic heme has proximal ligation from lysine, or histidine, and an exchangeable distal ligand bound within a pocket that includes a conserved histidine. Here we describe properties of a penta-heme cytochrome c nitrite reductase in which the distal His has been substituted by Asn. The variant is unable to catalyze nitrite reduction despite retaining the ability to reduce a proposed intermediate in that process, namely, hydroxylamine. A combination of electrochemical, structural and spectroscopic studies reveals that the variant enzyme simultaneously binds nitrite and electrons at the catalytic heme. As a consequence the distal His is proposed to play a key role in orienting the nitrite for N-O bond cleavage. The electrochemical experiments also reveal that the distal His facilitates rapid nitrite binding to the catalytic heme of the native enzyme. Finally it is noted that the thermodynamic descriptions of nitrite- and electron-binding to the active site of the variant enzyme are modulated by the prevailing oxidation states of the His/His ligated hemes. This is behavior that is likely to be displayed by other multi-centered redox enzymes such that there are wide implications for considering the determinants of catalytic activity in this important and varied group of oxidoreductases

    Asparagine and glutamine: using hydrogen atom contacts in the choice of side-chain amide orientation

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    Small-probe contact dot surface analysis, with all explicit hydrogen atoms added and their van der Waals contacts included, was used to choose between the two possible orientations for each of 1554 asparagine (Asn) and glutamine (Gln) side-chain amide groups in a dataset of 100 unrelated, high-quality protein crystal structures at 0.9 to 1.7 AÊ resolution. For the movable-H groups, each connected, closed set of local H-bonds was optimized for both H-bonds and van der Waals overlaps. In addition to the Asn/Gln ``¯ips'', this process included rotation of OH, SH, NH 3, and methionine methyl H atoms, ¯ip and protonation state of histidine rings, interaction with bound ligands, and a simple model of water interactions. However, except for switching N and O identity for amide ¯ips (or N and C identity for His ¯ips), no non-H atoms were shifted. Even in these very high-quality structures, about 20 % of the Asn/Gln side-chains required a 180 ¯ip to optimize H-bonding and/o

    Effectiveness of nurse delivered endoscopy: findings from randomised multi-institution nurse endoscopy trial (MINuET)

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    Objective To compare the clinical effectiveness of doctors and nurses in undertaking upper and lower gastrointestinal endoscopy. Design Pragmatic trial with Zelen's randomisation before consent to minimise distortion of existing practice. Setting 23 hospitals in the United Kingdom. In six hospitals, nurses undertook both upper and lower gastrointestinal endoscopy, yielding a total of 29 centres. Participants 67 doctors and 30 nurses. Of 4964 potentially eligible patients, we randomised 4128 (83%) and recruited 1888 (38%) from July 2002 to June 2003. Interventions Diagnostic upper gastrointestinal endoscopy and flexible sigmoidoscopy, undertaken with or without sedation, with the standard preparation, techniques, and protocols of participating hospitals. After referral for either procedure, patients were randomised between doctors and nurses. Main outcome measures Gastrointestinal symptom rating questionnaire (primary outcome), gastrointestinal endoscopy satisfaction questionnaire and state-trait anxiety inventory (all analysed by intention to treat); immediate and delayed complications; quality of examination and corresponding report; patients' preferences for operator; and new diagnoses at one year (all analysed according to who carried out the procedure). Results There was no significant difference between groups in outcome at one day, one month, or one year after endoscopy, except that patients were more satisfied with nurses after one day. Nurses were also more thorough than doctors in examining the stomach and oesophagus. While quality of life scores were slightly better in patients the doctor group, this was not statistically significant. Conclusions Diagnostic endoscopy can be undertaken safely and effectively by nurses. Trial registration International standard RCT 8276570

    Understanding substrate substituent effects to improve catalytic efficiency in the SABRE hyperpolarisation process

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    The use of parahydrogen based hyperpolarisation in NMR is becoming more widespread due to the rapidly expanding range of target molecules and low-cost of parahydrogen production. Hyperpolarisation via SABRE catalysis employs a metal complex to transfer polarisation from parahydrogen into a substrate whilst they are bound. In this paper we present a quantitative study of substrate–iridium ligation effects by reference to the substrates 4-chloropyridine (A), 4-pyridinecarboxaldehyde methyl hemiacetal (B), 4-methylpyridine (C) and 4-methoxypyridine (D), and evaluate the role they play in the SABRE catalysis. Substrates whose substituents enable stronger associations yield slower substrate dissociation rates (kd). A series of variable temperature studies link these exchange rates to optimal SABRE performance and reveal the critical impact of NMR relaxation times (T1). Longer catalyst residence times are shown to result in shorter substrate T1 values in solution as binding to iridium promotes relaxation thereby not only reducing SABRE efficiency but decreasing the overall level of achieved hyperpolarisation. Based on these data, a route to achieve more optimal SABRE performance is defined
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