119 research outputs found
On Compact Affine Quaternionic Curves and Surfaces
This paper is devoted to the study of affine quaternionic manifolds and to a possible classification of all compact affine quater- nionic curves and surfaces. It is established that on an affine quater- nionic manifold there is one and only one affine quaternionic structure. A direct result, based on the celebrated Kodaira Theorem that classifies all compact complex manifolds in complex dimension 2, states that the only compact affine quaternionic curves are the quaternionic tori. As for compact affine quaternionic surfaces, the study of their fundamental groups, together with the inspection of all nilpotent hypercomplex sim- ply connected 8-dimensional Lie Groups, identifies a path towards their classification
Quaternionic Toric Manifolds
In the present paper we introduce and study a new notion of toric manifold in the quaternionic setting. We develop a construction with which, starting from appropriate m-dimensional Delzant polytopes, we obtain manifolds of real dimension 4m, acted on by m copies of the group Sp(1) of unit quaternions. These manifolds are quaternionic regular and can be endowed with a 4-plectic structure and a generalized moment map. Convexity properties of the image of the moment map are studied. Quaternionic toric manifolds appear to be a large enough class of examples where one can test and study new results in quaternionic geometry
Ultrastructural Aspects of Unilateral Interspecific Incompatibility between Lycopersicum Peruvianum and L. Esculentum
SUMMARYObservations have been made, at the electron microscope, of the pollen tubes present in the styles of Lycopersicum esculentum and L. peruvianum after reciprocal crosses between the two species.The unilateral incompatibility barrier which isolates the two species when L. peruvianum is used as pistillate parent was then compared to the processes of pollen tube rejection which have been recently analysed (J. Cell Sci., 1972) after self-pollination in this self-incompatible species. Such a comparison, which was also carried out by means of fluorescence techniques, has permitted to find out that for both types of incompatibility the rejection process was characterised by a progressive disappearance of the callose-rich inner wall of the pollen tube and by an accumulation of bi-partite particles in the tube cytoplasm.In the case of unilateral incompatibility, however, the tube outer wall is gradually disaggregated while the callosic inner wall remains quite thick at the tube apex, becoming thinner and fin..
The emergence of gravity as a retro-causal post-inflation macro-quantum-coherent holographic vacuum Higgs-Goldstone field
We present a model for the origin of gravity, dark energy and dark matter:
Dark energy and dark matter are residual pre-inflation false vacuum random zero
point energy (w=-1) of large-scale negative, and short-scale positive pressure,
respectively, corresponding to the "zero point" (incoherent) component of a
superfluid (supersolid) ground state. Gravity, in contrast, arises from the 2nd
order topological defects in the post-inflation virtual "condensate" (coherent)
component. We predict, as a consequence, that the LHC will never detect exotic
real on-mass-shell particles that can explain dark matter. We also point out
that the future holographic dark energy de Sitter horizon is a total absorber
(in the sense of retro-causal Wheeler-Feynman action-at-a-distance
electrodynamics) because it is an infinite redshift surface for static
detectors. Therefore, the advanced Hawking-Unruh thermal radiation from the
future de Sitter horizon is a candidate for the negative pressure dark vacuum
energy.Comment: 8 pages, no figures. To appear in Proc. DICE2008 From Quantum
Mechanics through Complexity to Spacetime: the role of emergent dynamical
structures. Castello Pasquini/Castiglioncello (Tuscany), September 22-26,
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Star Architecture as Socio-Material Assemblage
Taking inspiration from new materialism and assemblage, the chapter deals with star architects and iconic buildings as socio-material network effects that do not pre-exist action, but are enacted in practice, in the materiality of design crafting and city building. Star architects are here conceptualized as part of broader assemblages of actors and practices ‘making star architecture’ a reality, and the buildings they design are considered not just as unique and iconic objects, but dis-articulated as complex crafts mobilizing skills, technologies, materials, and forms of knowledge not necessarily ascribable to architecture. Overcoming narrow criticism focusing on the symbolic order of icons as unique creations and alienated repetitions of capitalist development, the chapter’s main aim is to widen the scope of critique by bridging culture and economy, symbolism and practicality, making star architecture available to a broad, fragmented arena of (potential) critics, unevenly equipped with critical tools and differentiated experiences
Suppression of Plant Resistance Gene-Based Immunity by a Fungal Effector
The innate immune system of plants consists of two layers. The first layer, called basal resistance, governs recognition of conserved microbial molecules and fends off most attempted invasions. The second layer is based on Resistance (R) genes that mediate recognition of effectors, proteins secreted by pathogens to suppress or evade basal resistance. Here, we show that a plant-pathogenic fungus secretes an effector that can both trigger and suppress R gene-based immunity. This effector, Avr1, is secreted by the xylem-invading fungus Fusarium oxysporum f.sp. lycopersici (Fol) and triggers disease resistance when the host plant, tomato, carries a matching R gene (I or I-1). At the same time, Avr1 suppresses the protective effect of two other R genes, I-2 and I-3. Based on these observations, we tentatively reconstruct the evolutionary arms race that has taken place between tomato R genes and effectors of Fol. This molecular analysis has revealed a hitherto unpredicted strategy for durable disease control based on resistance gene combinations
Differences in access to Emergency Paediatric Intensive Care and care during Transport (DEPICT): study protocol for a mixed methods study
Introduction Following centralisation of UK paediatric intensive care, specialist retrieval teams were established who travel to general hospitals to stabilise and transport sick children to regional paediatric intensive care units (PICUs). There is national variation among these PICU retrieval teams (PICRTs) in terms of how quickly they reach the patient’s bedside and in the care provided during transport. The impact of these variations on clinical outcomes and the experience of stakeholders (patients, families and healthcare staff) is however unknown. The primary objective of this study is to address this evidence gap. Methods and analysis This mixed-methods project involves the following: (1) retrospective analysis of linked data from routine clinical audits (2014–2016) to assess the impact of service variations on 30-day mortality and other secondary clinical outcomes; (2) a prospective questionnaire study conducted at 24 PICUs and 9 associated PICRTs in England and Wales over a 12-month period in 2018 to collect experience data from parents of transported children as well as qualitative analysis of in-depth interviews with a purposive sample of patients, parents and staff to assess the impact of service variations on patient/family experience; (3) health economic evaluation analysing transport service costs (and other associated costs) against lives saved and longer term measurements of quality of life at 12 months in transported children and (4) mathematical modelling evaluating the costs and potential impact of different service configurations. A final work stream involves a series of stakeholder workshops to synthesise study findings and generate recommendations. Ethics and dissemination The study has been reviewed and approved by the Health Research Authority, ref: 2 18 569. Study results will be actively disseminated through peer-reviewed journals, conference presentations, social media, print and broadcast media, the internet and stakeholder workshops
Dimethyl fumarate in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial
Dimethyl fumarate (DMF) inhibits inflammasome-mediated inflammation and has been proposed as a treatment for patients hospitalised with COVID-19. This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing multiple treatments in patients hospitalised for COVID-19 (NCT04381936, ISRCTN50189673). In this assessment of DMF performed at 27 UK hospitals, adults were randomly allocated (1:1) to either usual standard of care alone or usual standard of care plus DMF. The primary outcome was clinical status on day 5 measured on a seven-point ordinal scale. Secondary outcomes were time to sustained improvement in clinical status, time to discharge, day 5 peripheral blood oxygenation, day 5 C-reactive protein, and improvement in day 10 clinical status. Between 2 March 2021 and 18 November 2021, 713 patients were enroled in the DMF evaluation, of whom 356 were randomly allocated to receive usual care plus DMF, and 357 to usual care alone. 95% of patients received corticosteroids as part of routine care. There was no evidence of a beneficial effect of DMF on clinical status at day 5 (common odds ratio of unfavourable outcome 1.12; 95% CI 0.86-1.47; p = 0.40). There was no significant effect of DMF on any secondary outcome
Dimethyl fumarate in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial
Dimethyl fumarate (DMF) inhibits inflammasome-mediated inflammation and has been proposed as a treatment for patients hospitalised with COVID-19. This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing multiple treatments in patients hospitalised for COVID-19 (NCT04381936, ISRCTN50189673). In this assessment of DMF performed at 27 UK hospitals, adults were randomly allocated (1:1) to either usual standard of care alone or usual standard of care plus DMF. The primary outcome was clinical status on day 5 measured on a seven-point ordinal scale. Secondary outcomes were time to sustained improvement in clinical status, time to discharge, day 5 peripheral blood oxygenation, day 5 C-reactive protein, and improvement in day 10 clinical status. Between 2 March 2021 and 18 November 2021, 713 patients were enroled in the DMF evaluation, of whom 356 were randomly allocated to receive usual care plus DMF, and 357 to usual care alone. 95% of patients received corticosteroids as part of routine care. There was no evidence of a beneficial effect of DMF on clinical status at day 5 (common odds ratio of unfavourable outcome 1.12; 95% CI 0.86-1.47; p = 0.40). There was no significant effect of DMF on any secondary outcome
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