739 research outputs found
What do near-term observations tell us about long-term developments in greenhouse gas emissions? A letter
Long-term scenarios developed by integrated assessment models are used in climate research to provide an indication of plausible long-term emissions of greenhouse gases and other radiatively active substances based on developments in the global energy system, land-use and the emissions associated with these systems The phenomena that determine these long-term developments (several decades or even centuries) are very different than those that operate on a shorter time-scales (a few years) Nevertheless, in the literature, we still often find direct comparisons between short-term observations and long-term developments that do not take into account the differing dynamics over these time scales In this letter, we discuss some of the differences between the factors that operate in the short term and those that operate in the long term We use long-term historical emissions trends to show that short-term observations are very poor indicators of long-term future emissions developments Based on this, we conclude that the performance of long-term scenarios should be evaluated against the appropriate, corresponding long-term variables and trends The research community may facilitate this by developing appropriate data sets and protocols that can be used to test the performance of long-term scenarios and the models that produce the
Iron phosphate glasses: Bulk properties and atomic scale structure
Bulk properties such as glass transition temperature, density and thermal expansion of iron phosphate glass compositions, with replacement of Cs by Ba, are investigated as a surrogate for the transmutation of 137Cs to 137Ba, relevant to the immobilisation of Cs in glass. These studies are required to establish the appropriate incorporation rate of 137Cs in iron phosphate glass. Density and glass transition temperature increases with the addition of BaO indicating the shrinkage and reticulation of the iron phosphate glass network. The average thermal expansion coefficient reduces from 19.8 Ă 10â6 Kâ1 to 13.4 Ă 10â6 Kâ1, when 25 wt. % of Cs2O was replaced by 25 wt. % of BaO in caesium loaded iron phosphate glass. In addition to the above bulk properties, the role of Ba as a network modifier in the structure of iron phosphate glass is examined using various spectroscopic techniques. The FeII content and average coordination number of iron in the glass network was estimated using Mössbauer spectroscopy. The FeII content in the un-doped iron phosphate glass and barium doped iron phosphate glasses was 20, 21 and 22 ± 1% respectively and the average Fe coordination varied from 5.3 ± 0.2 to 5.7 ± 0.2 with increasing Ba content. The atomic scale structure was further probed by Fe K-edge X-ray absorption spectroscopy. The average coordination number provided by extended X-ray absorption fine structure spectroscopy and X-ray absorption near edge structure was in good agreement with that given by the Mössbauer data
Nurse-led versus doctor-led care for bronchiectasis
Background: Specialist nursing roles to manage stable disease populations are being used to meet the needs of both patients and health services. With increasing cost pressures on health departments, alternative models such as nurse-led care are gaining momentum as a substitute for traditional doctor-led care. This review evaluates the safety, effectiveness, and health outcomes of nurses practising in autonomous roles while using advanced practice skills, within the context of bronchiectasis management in subacute, ambulatory, and/or community care. Objectives: To compare the effectiveness of nurse-led care versus doctor-led care in the management of stable bronchiectasis. Search methods: We searched the Cochrane Airways Group Specialised Register and bibliographies of selected papers in addition to grey literature such as electronic clinical trials registries. Searches were current as of March 2018. Selection criteria: Randomised controlled trials were eligible for inclusion in the review. Data collection and analysis: Two reviewers extracted and entered data from included studies. Primary outcomes were numbers of exacerbations requiring treatment with antibiotics, hospital admissions, and emergency department attendances. Main results: We included one United Kingdom (UK) study in the review. In this randomised controlled trial, a total of 80 participants, with a mean age of 58 years, were treated for 12 months by a specialist nurse or doctor, then were crossed over to the other clinician for the next 12 months. Two participants died during the study period. Six participants failed to cross over to nurse-led care because of unstable bronchiectasis. Overall, the level of study completion was high. Data show no difference in the numbers of exacerbations requiring treatment with antibiotics (rate ratio 1.09, 95% confidence interval (CI) 0.91 to 1.30, 80 participants, moderate-certainty evidence). Investigators reported more hospital admissions in the nurse-led care group (rate ratio 1.52, 95% CI 1.04 to 2.23, 80 participants, moderate-certainty evidence) and did not report emergency department attendance. For secondary outcomes, participants in the nurse-led care group used more healthcare resources during the first year of the trial. Increased admissions and greater use of resources made treatment costs for nurse-led groups' higher. Total costs for both years of the study were ÂŁ8,464 and ÂŁ5,228 for nurse-led care compared with doctor-led care. However, by the second year, treatment costs were almost equitable between the two groups, which may reflect the nurses' learning of how to better treat people with bronchiectasis. No statistically significant changes were observed in quality of life, exercise capacity, mortality, or lung function. Wide confidence intervals led to uncertainty regarding these results. Adverse events were not an outcome for this review. Authors' conclusions: This update of the review shows that only one trial met review criteria. Review authors were unable to demonstrate effectiveness of nurse-led care compared with doctor-led care on the basis of findings of a single study. The included study reported no significant differences, but limited evidence means that differences in clinical outcomes between nurse-led care and usual care within the setting of a specialist clinic remain unclear. Further research is required to determine whether nurse-led care is cost-effective, if guidelines and protocols for bronchiectasis management are followed does this increases costs and how effective nurse-led management of bronchiectasis is in other clinical settings such as inpatient and outreach
Shape Space Methods for Quantum Cosmological Triangleland
With toy modelling of conceptual aspects of quantum cosmology and the problem
of time in quantum gravity in mind, I study the classical and quantum dynamics
of the pure-shape (i.e. scale-free) triangle formed by 3 particles in 2-d. I do
so by importing techniques to the triangle model from the corresponding 4
particles in 1-d model, using the fact that both have 2-spheres for shape
spaces, though the latter has a trivial realization whilst the former has a
more involved Hopf (or Dragt) type realization. I furthermore interpret the
ensuing Dragt-type coordinates as shape quantities: a measure of
anisoscelesness, the ellipticity of the base and apex's moments of inertia, and
a quantity proportional to the area of the triangle. I promote these quantities
at the quantum level to operators whose expectation and spread are then useful
in understanding the quantum states of the system. Additionally, I tessellate
the 2-sphere by its physical interpretation as the shape space of triangles,
and then use this as a back-cloth from which to read off the interpretation of
dynamical trajectories, potentials and wavefunctions. I include applications to
timeless approaches to the problem of time and to the role of uniform states in
quantum cosmological modelling.Comment: A shorter version, as per the first stage in the refereeing process,
and containing some new reference
Measurement of the Dalitz plot slope parameters for K- -> pi0 pi0 pi- decay using ISTRA+ detector
The Dalitz plot slope parameters g, h and k for the K- -> pi0 pi0 pi- decay
have been measured using in-flight decays detected with the ISTRA+ setup
operating in the 25 GeV negative secondary beam of the U-70 PS. About 252 K
events with four-momenta measured for the pi- and four involved photons were
used for the analysis. The values obtained g=0.627+/-0.004(stat)+/-0.010(syst),
h=0.046+/-0.004(stat)+/-0.012(syst), k=0.001+/-0.001(stat)+/-0.002(syst) are
consistent with the world averages dominated by K+ data, but have significantly
smaller errors.Comment: LaTeX, 10 pages, 8 eps-figures, update of IHEP 2002-1
Spin-orbit coupling and semiclassical electron dynamics in noncentrosymmetric metals
Spin-orbit coupling of electrons with the crystal lattice plays a crucial
role in materials without inversion symmetry, lifting spin degeneracy of the
Bloch states and endowing the resulting nondegenerate bands with complex spin
textures and topologically nontrivial wavefunctions. We present a detailed
symmetry-based analysis of the spin-orbit coupling and the band degeneracies in
noncentrosymmetric metals. We systematically derive the semiclassical equations
of motion for fermionic quasiparticles near the Fermi surface, taking into
account both the spin-orbit coupling and the Zeeman interaction with an applied
magnetic field. Some of the lowest-order quantum corrections to the equations
of motions can be expressed in terms of a fictitious "magnetic field" in the
momentum space, which is related to the Berry curvature of the band
wavefunctions. The band degeneracy points or lines serve as sources of a
topologically nontrivial Berry curvature. We discuss the observable effects of
the wavefunction topology, focusing, in particular, on the modifications to the
Lifshitz-Onsager semiclassical quantization condition and the de Haas-van
Alphen effect in noncentrosymmetric metals.Comment: 38 LaTeX page
The Effects of Disorder on the Quantum Hall State
A disorder-averaged Hartree-Fock treatment is used to compute the density of
single particle states for quantum Hall systems at filling factor . It
is found that transport and spin polarization experiments can be simultaneously
explained by a model of mostly short-range effective disorder. The slope of the
transport gap (due to quasiparticles) in parallel field emerges as a result of
the interplay between disorder-induced broadening and exchange, and has
implications for skyrmion localization.Comment: 4 pages, 3 eps figure
Iron phosphate glasses: Bulk properties and atomic scale structure
© 2017 The Authors Bulk properties such as glass transition temperature, density and thermal expansion of iron phosphate glass compositions, with replacement of Cs by Ba, are investigated as a surrogate for the transmutation of 137 Cs to 137 Ba, relevant to the immobilisation of Cs in glass. These studies are required to establish the appropriate incorporation rate of 137 Cs in iron phosphate glass. Density and glass transition temperature increases with the addition of BaO indicating the shrinkage and reticulation of the iron phosphate glass network. The average thermal expansion coefficient reduces from 19.8 Ă 10 â6 K â1 to 13.4 Ă 10 â6 K â1 , when 25 wt. % of Cs 2 O was replaced by 25 wt. % of BaO in caesium loaded iron phosphate glass. In addition to the above bulk properties, the role of Ba as a network modifier in the structure of iron phosphate glass is examined using various spectroscopic techniques. The Fe II content and average coordination number of iron in the glass network was estimated using Mössbauer spectroscopy. The Fe II content in the un-doped iron phosphate glass and barium doped iron phosphate glasses was 20, 21 and 22 ± 1% respectively and the average Fe coordination varied from 5.3 ± 0.2 to 5.7 ± 0.2 with increasing Ba content. The atomic scale structure was further probed by Fe K-edge X-ray absorption spectroscopy. The average coordination number provided by extended X-ray absorption fine structure spectroscopy and X-ray absorption near edge structure was in good agreement with that given by the Mössbauer data
Structure of SPH (Self-Incompatibility Protein Homologue) Proteins: a Widespread Family of Small, Highly Stable, Secreted Proteins
SPH proteins are a large family of small, disulphide-bonded, secreted proteins, initially found in the self-incompatibility response in the field poppy , but now known to be widely distributed in plants, many containing multiple members of this protein family. Using the Origami strain of , we expressed one member of this family, SPH15 from , as a folded thioredoxin-fusion protein and purified it from the cytosol. The fusion protein was cleaved and characterised by analytical ultracentrifugation, circular dichroism, and NMR spectroscopy. This showed that SPH15 is monomeric and temperature stable, with a beta-sandwich structure. The four strands in each sheet have the same topology as the unrelated proteins; human transthyretin, bacterial TSSJ, and pneumolysin, with no discernable sequence similarity. The NMR-derived structure was compared with a model, made using a new deep learning algorithm based on co-evolution/correlated mutations, DeepCDPred, validating the method. The DeepCDPred method and homology modelling to SPH15 were then both used to derive models of the 3D structure of the three known PrsS proteins from , which have only 15-18% sequence homology to SPH15. The DeepCDPred method gave models with lower Discreet Optimised Protein Energy (DOPE) scores than the homology models. Three loops at one end of the poppy structures are postulated to interact with their respective pollen receptors to instigate programmed cell death in pollen tubes. [Abstract copyright: ©2019 The Author(s).
InfluĂȘncia de prĂĄticas culturais e da resistĂȘncia genĂ©tica na intensidade do cancro da haste e produção de soja no Cerrado
Os efeitos de prĂĄticas culturais e resistĂȘncia genĂ©tica na intensidade ao cancro-da-haste da soja (Diaporthe phaseolorum f.sp. meridionalis - Dpm) foram examinados na safra 1995-96 em ĂĄreas de produção comercial, que haviam sido severamente atacadas na safra anterior (1994-95). Um experimento investigou os efeitos de cultivo mĂnimo (MT) e do plantio direto (NT) no desenvolvimento da doença e produtividade das cultivares FT-Cristalina e FT-Seriema. Em outro experimento, semeado em plantio direto, estudou-se o efeito da densidade de plantas (8, 15, 21 e 36 plantas/m) no desenvolvimento da doença e produtividade das cvs. FT-Cristalina (suscetivel), FT- 101 (moderadamente resistente) e FT-104 (resistente). IncidĂȘncia e severidade da doença foram menores em NT do que em MT. A produtividade aumentou no sistema NT (23% para âFT-Cristalinaâ e 14% para âFT-Seriemaâ), comparada com as produtividades em MT. As curvas de progresso da doença foram melhor descritas pelos mo- delos de Gompertz e logĂstico. A severidade do cancro aumentou pro- porcionalmente ao aumento das densidades de plantio nas cvs. suscetĂvel e moderadamente resistente. No final do ciclo, 100% das plantas da cv. FT-Cristalina estavam infetadas por Dpm, em todas as densidades de plantio. NĂveis intermediĂĄrios de doença foram observa- dos na cv. FT-101, enquanto apenas nĂveis muito baixos de doença ocorreram na cv. FT-104. Estabeleceu-se uma correlação negativa entre severidade de cancro-da-haste e produção. Algumas das prĂĄticas estudadas demonstraram potential para aplicação direta no controle da doença, e poderiam ser combinadas considerando-se seus efeitos aditivos.Field experiments were conducted in the 1995-96 soybean (Glycine max) growing season to evaluate the effects of cultural practices and host genetic resistance on the intensity of soybean stem canker, caused by Diaporthe phaseolorum f.sp. meridionalis (Dpm). Experiments were conducted in a commercial field severely infected in the previous (1994-95) season. In one study, minimum tillage (MT) and no-tillage (NT) cropping systems were investigated for their effects on disease development and on plant yields in cvs. FT- Cristalina (susceptible) and FT-Seriema (moderately resistant). Another study evaluated the effects of plant densities (8, 15, 21 and 36 plants/m) on disease development in cvs. FT-Cristalina, FT-101 (moderately resistant) and FT-104 (resistant). Disease incidence and severity were consistently lower in NT than in MT, and plant yields were increased by 23% and 14% in the NT system for the susceptible and moderately resistant cultivars, respectively, compared to the yields in the MT system. The Gompertz and Logistic models described well the disease progress curves in all situations. For both susceptible and moderately resistant cultivars, disease severity increased proportionately to the increase in plant densities. At the end of the season, 100% of the plants of cv. FT-Cristalina were infected by Dpm, at all plant densities. Disease levels on cv. FT-101 were intermediate while only very low disease levels were recorded on cv. FT-104. There was a consistent negative correlation between stem canker severity and yield. Some practices demonstrated potential for direct application in disease control, and could be combined considering their additive effects
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