1,019 research outputs found
Active current sheets and hot flow anomalies in Mercury's bow shock
Hot flow anomalies (HFAs) represent a subset of solar wind discontinuities
interacting with collisionless bow shocks. They are typically formed when the
normal component of motional (convective) electric field points toward the
embedded current sheet on at least one of its sides. The core region of an HFA
contains hot and highly deflected ion flows and rather low and turbulent
magnetic field. In this paper, we report first observations of HFA-like events
at Mercury identified over a course of two planetary years. Using data from the
orbital phase of the MErcury Surface, Space ENvironment, GEochemistry, and
Ranging (MESSENGER) mission, we identify a representative ensemble of active
current sheets magnetically connected to Mercury's bow shock. We show that some
of these events exhibit unambiguous magnetic and particle signatures of HFAs
similar to those observed earlier at other planets, and present their key
physical characteristics. Our analysis suggests that Mercury's bow shock does
not only mediate the flow of supersonic solar wind plasma but also provides
conditions for local particle acceleration and heating as predicted by previous
numerical simulations. Together with earlier observations of HFA activity at
Earth, Venus and Saturn, our results confirm that hot flow anomalies are a
common property of planetary bow shocks, and show that the characteristic size
of these events is of the order of one planetary radius.Comment: 39 pages, 15 figures, 2 table
Mathematical Models for Estimating the Risk of vCJD Transmission
We present two different simple models for vCJD transmission by blood transfusion. Both models indicate that transfusions alone are unlikely to cause more than a few infections, unless the number of primary cases increases.
To improve our models, future work should pursue data collection, empirical estimation of the model parameters, and examination of the underlying assumptions of our frameworks.
Further improvements could also include examining susceptibility to vCJD infection by age group and iatrogenic infections introduced through surgical instruments. Regarding the latter, it may be worthwhile to conduct experiments to quantify the transmission of prions from an infected surgical instrument after repeated sterilization procedures
A Core outcome set for childhood epilepsy treated with ketogenic diet therapy (CORE-KDT study): international parent and health professional consensus.
OBJECTIVE: Ketogenic diet therapy (KDT) can result in benefits (seizure and non-seizure related) for children with drug resistant epilepsy. However, clinical trials report a wide range of outcomes making synthesis of evidence difficult, and do not adequately reflect parent views on important outcomes for their child. To address this, we established the first international parent, health professional and researcher consensus to develop a core outcome set, guided by the Core Outcome Measures in Effectiveness Trials (COMET) Initiative (COMET registration #1116). METHODS: Ethical approval was granted (London-Surrey REC19/LO/1680). A scoping review and interviews with parents identified a comprehensive list of potentially important outcomes, followed by a two-round online Delphi survey of parents and health professionals to prioritise outcomes of importance for inclusion in a core outcome set. This informed a stakeholder consensus meeting and consultation process to finalise the core outcome set. RESULTS: In total, 97 outcomes were identified; 90 from the scoping review and seven from parent interviews. These were rationalised to 77 by the study advisory group, then rated in the first Delphi round by 49 parents and 96 health professionals who suggested 12 new outcomes for rating in round two. 66% of participants (30 parents and 66 professionals) completed round two, where 22 outcomes met criteria for inclusion. In the consensus meeting (9 parents and 13 professionals), 27 undecided outcomes were discussed and scored; one further outcome reached consensus for inclusion. After consultation and ratification, 14 outcomes across five domains were included in the core outcome set. SIGNIFICANCE: A core outcome set for childhood epilepsy treated with KDT has been developed, incorporating the views of international parents and professionals. Implementation in research and clinical settings will standardise outcome selection and reporting, facilitate data synthesis and ultimately enhance the relevance of outcomes to parents, researchers and health professionals
Being an Early-Career CMS Academic in the Context of Insecurity and âExcellenceâ: The Dialectics of Resistance and Compliance
Drawing on a dialectical approach to resistance, we conceptualise the latter as a multifaceted, pervasive and contradictory phenomenon. This enables us to examine the predicament in which early-career Critical Management Studies academics find themselves in the current times of academic insecurity and âexcellenceâ, as gleaned through this groupâs understandings of themselves as resisters and participants in the complex and contradictory forces constituting their field. We draw on 24 semi-structured interviews to map our participantsâ accounts of themselves as resisters in terms of different approaches to tensions and contradictions between, on the one hand, the intervieweesâ Critical Management Studies alignment and, on the other, the ethos of business school neoliberalism. Emerging from this analysis are three contingent and interlinked narratives of resistance and identity â diplomatic, combative and idealistic â each of which encapsulates a particular mode (negotiation, struggle, and laying oneâs own path) of engaging with the relationship between Critical Management Studies and the business school ethos. The three narratives show how early-career Critical Management Studies academics not only use existing tensions, contradictions, overlaps and alliances between these positions to resist and comply with selected forces within each, but also contribute to the (re-)making of such overlaps, alliances, tensions and contradictions. Through this reworking of what it means to be both Critical Management Studies scholars and business school academics, we argue, early-career Critical Management Studies academics can be seen as active resisters and re-constituters of their complex field
Hidden Symmetry of Higher Dimensional Kerr-NUT-AdS Spacetimes
It is well known that 4-dimensional Kerr-NUT-AdS spacetime possesses the
hidden symmetry associated with the Killing-Yano tensor. This tensor is
"universal" in the sense that there exist coordinates where it does not depend
on any of the free parameters of the metric. Recently the general higher
dimensional Kerr-NUT-AdS solutions of the Einstein equations were obtained. We
demonstrate that all these metrics with arbitrary rotation and NUT parameters
admit a universal Killing-Yano tensor. We give an explicit presentation of the
Killing-Yano and Killing tensors and briefly discuss their properties.Comment: 4 pages, some discussion and references are adde
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Ethical trade, people and forests (A manual)
This manual is aimed at providing both an introduction to the complex maze of ethical trading approaches and practical information on how to do ethical trading, for those tackling or facing poverty and those promoting sustainable livelihoods. It focuses on the fair trade, forest and timber certification, organic production and conservation driven trade options
Existential learning and adolescent identity: Finding meaning through boundary situations
Existential psychology places emphasis on boundary situations as a potential source of learning and development. These experiences are situations when oneâs identity does not fit the new demands and experiences, bringing forth existential insecurity and often leading to a more profound change in oneâs mode of being. Our study aimed to understand identity learning through boundary experiences in adolescence through the story of âPilviâ, a pre-elite Finnish alpine skier who terminated her promising athletic career at the age of 18. She was interviewed using a low-structured approach, twice before and twice after her athletic retirement. We analysed her story using existential-narrative approach (Richert, 2010) with a focus on boundary situations and loss of athletic identity. A pivotal moment for Pilvi was the introduction of new skis that she could not adjust to, shattering her athletic identity that gained meaning from athletic success. The disruption also revealed the loneliness of her sport life-project underpinned by a lack of shared meaning with her father, teammates and coach. After abandoning her sport life-project and experiencing a personal crisis, she reflected on learning about her emotions, accepting her limitations and âwasting timeâ in sport; however, she also sought to transfer her sport life themes of success and winning to education to bring continuity to her identity. The tension with her father shaped her storytelling throughout the interviews. We discuss the implications of our findings for psychological and career counselling services for talented adolescents
The Chevreton Tensor and Einstein-Maxwell Spacetimes Conformal to Einstein Spaces
In this paper we characterize the source-free Einstein-Maxwell spacetimes
which have a trace-free Chevreton tensor. We show that this is equivalent to
the Chevreton tensor being of pure-radiation type and that it restricts the
spacetimes to Petrov types \textbf{N} or \textbf{O}. We prove that the trace of
the Chevreton tensor is related to the Bach tensor and use this to find all
Einstein-Maxwell spacetimes with a zero cosmological constant that have a
vanishing Bach tensor. Among these spacetimes we then look for those which are
conformal to Einstein spaces. We find that the electromagnetic field and the
Weyl tensor must be aligned, and in the case that the electromagnetic field is
null, the spacetime must be conformally Ricci-flat and all such solutions are
known. In the non-null case, since the general solution is not known on closed
form, we settle with giving the integrability conditions in the general case,
but we do give new explicit examples of Einstein-Maxwell spacetimes that are
conformal to Einstein spaces, and we also find examples where the vanishing of
the Bach tensor does not imply that the spacetime is conformal to a -space.
The non-aligned Einstein-Maxwell spacetimes with vanishing Bach tensor are
conformally -spaces, but none of them are conformal to Einstein spaces.Comment: 22 pages. Corrected equation (12
Research encounters, reflexivity and supervision
Reflexivity in qualitative and ethnographic social science research can provide a rich source of data, especially regarding the affective, performative and relational aspects of interviews with research subjects. This paper explores by means of three case examples different ways of accessing and using such reflexivity. The examples are drawn from an empirical psycho-social study into the identity transitions of first-time mothers in an inner-city multicultural environment. Fieldnotes and supervision were used to engage with researcher subjectivity, to enhance the productive use of reflexivity and to address the emotional work of research. The methodology of the supervision was psychoanalytic, in its use of a boundaried frame and of psychoanalytic forms of noticing oneself, of staying engaged emotionally as well as creating a reflective distance. The examples illustrate how this can enhance the knowledge gained about the research subjects
Theorizing dramaturgical resistance leadership from the leadership campaigns of Jeremy Corbyn
What are the practices through which resistance leadership transitions from marginality to power? We present a framework of dramaturgical resistance leadership, paying particular attention to the relational dynamics between leaders, internal factions and external stakeholders. In doing so, we draw on an âexpandedâ social drama analysis framework informed by the work of social anthropologist Victor Turner, incorporating insights from the resistance and critical leadership studies literatures. We develop our framework through a narrative case analysis of the British Labour Partyâs 2015 and 2016 internal elections of its current leader Jeremy Corbyn where we identify a space between the phases of relational crisis and redress that offers possibilities for the enhancement and growth of resistance leadership. Within this space, we identify three practices of dramaturgical resistance leadership: âanti-establishment leaderingâ, âorganizational redrawingâ, and a âtrifold focusâ. These offer a means of rethinking the purpose and role of leaders within resistance movements alongside the co-constituted relations and generative practices that enable resisting groups to gain traction
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