1,051 research outputs found
Chemical characteristics of macroscopic pyrogenic carbon following millennial-scale environmental exposure
Pyrogenic Carbon (PyC) is ubiquitous in global environments, and is now known to form a significant, and dynamic component of the global carbon cycle, with at least some forms of PyC persisting in their depositional environment for many millennia. Despite this, the factors that determine the turnover of PyC remain poorly understood, as do the physical and chemical changes that this material undergoes when exposed to the environment over tens of thousands of years. Here, we present the results of an investigation to address these knowledge gaps through chemical and physical analysis of a suite of wood PyC samples exposed to the environment for varying time periods, to a maximum of >90,000 years. This includes an assessment of the quantity of resistant carbon, known as Stable Polyaromatic Carbon (SPAC) versus more chemically labile carbon in the samples. We find that, although production temperature is likely to determine the initial âdegradation potentialâ of PyC, an extended exposure to environmental conditions does not necessarily mean that remaining PyC always progresses to a âSPAC-dominantâ state. Instead, some ancient PyC can be composed largely of chemical components typically thought of as environmentally labile, and it is likely that the depositional environment drives the trajectory of preservation versus loss of PyC over time. This has important implications for the size of global PyC stocks, which may have been underestimated, and also for the potential loss of previously stored PyC, when its depositional environment alters through environmental or climatic changes
Measuring commissionersâ willingness-to-pay for community based childhood obesity prevention programmes using a discrete choice experiment
Background:
In the UK, rates of childhood obesity remain high. Community based programmes for child obesity prevention are available to be commissioned by local authorities. However, there is a lack of evidence regarding how programmes are commissioned and which attributes of programmes are valued most by commissioners. The aim of this study was to determine the factors that decision-makers prioritise when commissioning programmes that target childhood obesity prevention.
Methods:
An online discrete choice experiment (DCE) was used to survey commissioners and decision makers in the UK to assess their willingness-to-pay for childhood obesity programmes.
Results:
A total of 64 commissioners and other decision makers completed the DCE. The impact of programmes on behavioural outcomes was prioritised, with participants willing to pay an extra ÂŁ16,600/year if average daily fruit and vegetable intake increased for each child by one additional portion. Participants also prioritised programmes that had greater number of parents fully completing them, and were willing to pay an extra ÂŁ4810/year for every additional parent completing a programme. The number of parents enrolling in a programme (holding the number completing fixed) and hours of staff time required did not significantly influence choices.
Conclusions:
Emphasis on high programme completion rates and success increasing childrenâs fruit and vegetable intake has potential to increase commissioning of community based obesity prevention programmes
Consequences of a Killing symmetry in spacetime's local structure
In this paper we discuss the consequences of a Killing symmetry on the local
geometrical structure of four-dimensional spacetimes. We have adopted the point
of view introduced in recent works where the exterior derivative of the Killing
plays a fundamental role. Then, we study some issues related with this approach
and clarify why in many circumstances its use has advantages with respect to
other approaches. We also extend the formalism developed in the case of vacuum
spacetimes to the general case of an arbitrary energy-momentum content.
Finally, we illustrate our framework with the case of spacetimes with a
gravitating electromagnetic field.Comment: 20 pages, LaTeX2e, IOP style. Revised version accepted for
publication in Classical and Quantum Gravit
New first integral for twisting type-N vacuum gravitational fields with two non-commuting Killing vectors
A new first integral for the equations corresponding to twisting type-N
vacuum gravitational fields with two non-commuting Killing vectors is
introduced. A new reduction of the problem to a complex second-order ordinary
differential equation is given. Alternatively, the mentioned first integral can
be used in order to provide a first integral of the second-order complex
equation introduced in a previous treatment of the problem.Comment: 7 pages, LaTeX, uses ioplppt.sty and iopl12.sty; to be published in
Class. Quantum Gra
From a certain point of view: sensory phenomenological envisionings of running space and place
The precise ways in which we go about the mundane, repetitive, social actions of everyday life are central concerns of ethnographers and theorists working within the traditions of the sociology of the mundane and sociological phenomenology. In this article, we utilize insights derived from sociological phenomenology and the newly developing field of sensory sociology to investigate a particular, mundane, and embodied social practice, that of training for distance running in specific places: our favored running routes. For, despite a growing body of ethnographic studies of particular sports, little analytic attention has been devoted to the actual, concrete practices of âdoingâ or âproducingâ sporting activity, particularly from a sensory ethnographic perspective. Drawing upon data from a 2-year joint autoethnographic research project, here we explore the visual dimension, focusing upon three key themes in relation to our runnersâ visualization of, respectively, (1) hazardous places, (2) performance places, (3) the timeâspaceâplace nexus
Cluster randomised controlled feasibility study of HENRY: a community-based intervention aimed at reducing obesity rates in preschool children
Background
Community-based obesity prevention interventions are often commissioned despite the limited evidence base. HENRY (Health, Exercise, Nutrition for the Really Young) is a programme delivered to parents of preschool children across the UK. Early evidence suggests that it may be effective, but a robust evaluation has not been conducted. We initiated a systematic evaluation of HENRY by studying the feasibility of conducting a multi-centre definitive trial to evaluate its effectiveness and cost-effectiveness to prevent obesity. Objectives were to assess the feasibility of recruiting local authorities, centres and parents; test processes and time required to train and certify intervention staff; explore HENRY commissioning processes; identify potential sources (and associated impact) of contamination; and consider the feasibility of trial procedures.
Methods
We conducted a multi-centre, open labelled, two group, prospective, cluster randomised, controlled, feasibility study, with embedded process evaluation and pre-defined criteria for progression to definitive trial. We sought to recruit 120 parents from 12 childrenâs centres, across two UK local authority (government) areas. Within each local authority, we planned to randomise three centres to HENRY and three to âstandard careâ control. Our plan was to collect data in family homes at baseline and 12 months, including parent and child height and weight, and parent-reported questionnaires on self-efficacy, feeding, eating habits, quality of life and resource use. Contamination, implementation and study acceptability were explored using parent interviews.
Results
We recruited two local authorities and 12 childrenâs centres within eight months. One hundred and seventeen parents were recruited (average 3.9 parents per programme) and follow-up data were collected from 85% of participants. Process data from 20 parents and 24 members of staff indicate that both would benefit from more detail about their involvement as participants, but that methods were acceptable. Contamination was likely, though the impact of this on behaviour was unclear.
Conclusion
Our findings indicate that a cluster RCT of HENRY to assess its effect on childhood obesity prevention is feasible. This study has allowed us to design a pragmatic definitive trial with minimal bias, taking account of lessons learnt from conducting evaluation research in public health settings
A Geometric Formulation of Quantum Stress Fields
We present a derivation of the stress field for an interacting quantum system
within the framework of local density functional theory. The formulation is
geometric in nature and exploits the relationship between the strain tensor
field and Riemannian metric tensor field. Within this formulation, we
demonstrate that the stress field is unique up to a single ambiguous parameter.
The ambiguity is due to the non-unique dependence of the kinetic energy on the
metric tensor. To illustrate this formalism, we compute the pressure field for
two phases of solid molecular hydrogen. Furthermore, we demonstrate that
qualitative results obtained by interpreting the hydrogen pressure field are
not influenced by the presence of the kinetic ambiguity.Comment: 22 pages, 2 figures. Submitted to Physical Review B. This paper
supersedes cond-mat/000627
Walking the walk: a phenomenological study of long distance walking
Evidence suggests that regular walking can elicit significant psychological benefits although little evidence exists concerning long distance walking. The purpose of this study was to provide detailed accounts of the experiences of long distance walkers. Phenomenological interviews were conducted with six long distance walkers. Data were transcribed verbatim before researchers independently analyzed the transcripts. Participants reported a cumulative effect with positive feelings increasing throughout the duration of the walk. Long distance walking elicited positive emotions, reduced the effects of life-stress, and promoted an increased sense of well-being and personal growth. Results are aligned to theories and concepts from positive psychology
Haploinsufficiency of the NOTCH1 Receptor as a Cause of Adams-Oliver Syndrome With Variable Cardiac Anomalies.
BACKGROUND: Adams-Oliver syndrome (AOS) is a rare disorder characterized by congenital limb defects and scalp cutis aplasia. In a proportion of cases, notable cardiac involvement is also apparent. Despite recent advances in the understanding of the genetic basis of AOS, for the majority of affected subjects, the underlying molecular defect remains unresolved. This study aimed to identify novel genetic determinants of AOS. METHODS AND RESULTS: Whole-exome sequencing was performed for 12 probands, each with a clinical diagnosis of AOS. Analyses led to the identification of novel heterozygous truncating NOTCH1 mutations (c.1649dupA and c.6049_6050delTC) in 2 kindreds in which AOS was segregating as an autosomal dominant trait. Screening a cohort of 52 unrelated AOS subjects, we detected 8 additional unique NOTCH1 mutations, including 3 de novo amino acid substitutions, all within the ligand-binding domain. Congenital heart anomalies were noted in 47% (8/17) of NOTCH1-positive probands and affected family members. In leukocyte-derived RNA from subjects harboring NOTCH1 extracellular domain mutations, we observed significant reduction of NOTCH1 expression, suggesting instability and degradation of mutant mRNA transcripts by the cellular machinery. Transient transfection of mutagenized NOTCH1 missense constructs also revealed significant reduction in gene expression. Mutant NOTCH1 expression was associated with downregulation of the Notch target genes HEY1 and HES1, indicating that NOTCH1-related AOS arises through dysregulation of the Notch signaling pathway. CONCLUSIONS: These findings highlight a key role for NOTCH1 across a range of developmental anomalies that include cardiac defects and implicate NOTCH1 haploinsufficiency as a likely molecular mechanism for this group of disorders
âGet yourself some nice, neat, matching box filesâ: research administrators and occupational identity work
To date, qualitative research into occupational groups and cultures within academia has been relatively scarce, with an almost exclusive concentration upon teaching staff within universities and colleges. This article seeks to address this lacuna and applies the interactionist concept of âidentity workâ in order to examine one specific group to date under-researched: graduate research administrators.
This occupational group is of sociological interest as many of its members appear to span the putative divide between âacademicâ and âadministrativeâ occupational worlds within higher education. An exploratory, qualitative research project was undertaken, based upon interviews with
27 research administrators. The study analyses how research administrators utilise various forms of identity work to sustain credible occupational identities, often in the face of considerable challenge from their academic colleagues
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