1,483 research outputs found
Measuring asthma control in group studies: do we need airway calibre and rescue β2-agonist use?
AbstractCollection of airway calibre and β2-agonist data in large clinical trials and epidemiological surveys is sometimes difficult and may be an inefficient use of resources. The aim of this study was to determine whether the omission of the forced expiratory volume in 1 sec (FEV1) and β2-agonist questions from the seven-item Asthma Control Questionnaire (ACQ) alters its measurement properties and validity.In an observational study, 50 adults with symptomatic asthma attended the clinic at 0, 1, 5 and 9 weeks to complete the ACQ and other measures of asthma status.All patients completed the study and provided complete data sets. Omission of the FEV1andβ2 -agonist questions from the ACQ made minimal difference to the reliability, responsiveness, and both cross-sectional and longitudinal validity of the instrument. Omission of the FEV1question significantly lowered the summary score (P<0·0001) but omission of the β2-agonist question did not alter it (P>0·05).In group studies, both the FEV1and β2-agonist questions may be omitted from the ACQ without changing the validity or the measurement properties of the instrument. Lowering of the summary score by the omission of the FEV1question means that data from this abbreviated form cannot be combined with or compared to data collected using the full questionnaire
A conditional silencing suppression system for transient expression.
RNA silencing is a powerful tool deployed by plants against viral infection and abnormal gene expression. Plant viruses have evolved a suite of silencing suppressors for counter-defense, which are also widely used to boost transcript and protein accumulation in transient assays. However, only wild type silencing suppressor proteins have been reported to date. Here we demonstrate that P0 of Potato leafroll virus (PLRV), PLP0, can be split into two proteins that only show silencing suppression activity upon co-expression. We cloned each of these proteins in two different constructs and transiently co-infiltrated them in N. benthamiana leaves. We expressed a fluorescent protein from one of the vectors and observed that cells expressing both halves of PLP0 suppressed gene silencing. Further, we showed that Q system of Neurospora crassa, based on co-expression of a transcription activator and inhibitor, is functional in agroinfiltrated leaves of N. benthamiana. Q system combined with the split PLP0 system showed very tight co-expression of Q system's transcriptional activator and inhibitor. Altogether, our experiments demonstrate a functioning conditional silencing suppressor system and its potential as a powerful tool for transient expression in N. benthamiana leaves, as well as the application of the Q system in plants
Resonantly damped surface and body MHD waves in a solar coronal slab with oblique propagation
The theory of magnetohydrodynamic (MHD) waves in solar coronal slabs in a
zero- configuration and for parallel propagation of waves does not allow
the existence of surface waves. When oblique propagation of perturbations is
considered both surface and body waves are able to propagate. When the
perpendicular wave number is larger than a certain value, the body kink mode
becomes a surface wave. In addition, a sausage surface mode is found below the
internal cut-off frequency. When non-uniformity in the equilibrium is included,
surface and body modes are damped due to resonant absorption. In this paper,
first, a normal-mode analysis is performed and the period, the damping rate,
and the spatial structure of eigenfunctions are obtained. Then, the
time-dependent problem is solved, and the conditions under which one or the
other type of mode is excited are investigated.Comment: 19 pages, 9 figures, accepted for publication in Solar Physic
Growth and characterisation of InAsP/AlGaInP QD laser structures
We present a study of metalorganic vapour phase epitaxy of ternary InAsP quantum dots on AlGaInP/GaAs. The properties of InAsP QD laser structures were compared with reference samples containing binary InP QDs. Based on X-ray diffraction, the molar fraction of As in InAsP QDs was estimated to be ~25%. Room temperature liquid contact electro-luminescence measurements revealed a long wavelength shift of the InAsP QD emission to ~775 nm as compared with the InP QD emission at 716 nm and an increased full width at half maximum of the spontaneous emission (71 meV vs 50 meV). As cleaved, 4 mm long and 50 μm wide InAsP QD lasers operated in a pulsed regime at room temperature at ~770 nm with a threshold current density of 155 A/cm2 and a maximum output optical power of at least ~200 mW. The maximum operation temperature was at least 380 K
The failed liberalisation of Algeria and the international context: a legacy of stable authoritarianism
The paper attempts to challenge the somewhat marginal role of international factors in the study of transitions to democracy. Theoretical and practical difficulties in proving causal mechanisms between international variables and domestic outcomes can be overcome by defining the international dimension in terms of Western dominance of world politics and by identifying Western actions towards democratising countries. The paper focuses on the case of Algeria, where international factors are key in explaining the initial process of democratisation and its following demise. In particular, the paper argues that direct Western policies, the pressures of the international system and external shocks influence the internal distribution of power and resources, which underpins the different strategies of all domestic actors. The paper concludes that analysis based purely on domestic factors cannot explain the process of democratisation and that international variables must be taken into more serious account and much more detailed
Magneto-Acoustic Wave Oscillations in Solar Spicules
Some observations suggest that solar spicules show small amplitude and high
frequency oscillations of magneto-acoustic waves, which arise from photospheric
granular forcing. We apply the method of MHD seismology to determine the period
of kink waves. For this purposes, the oscillations of a magnetic cylinder
embedded in a field-free environment is investigated. Finally, diagnostic
diagrams displaying the oscillatory period in terms of some equilibrium
parameters are provided to allow a comparison between theoretical results and
those coming from observations.Comment: 10 pages, 4 fig
Class and rank of differential modules
A differential module is a module equipped with a square-zero endomorphism.
This structure underpins complexes of modules over rings, as well as
differential graded modules over graded rings. We establish lower bounds on the
class--a substitute for the length of a free complex--and on the rank of a
differential module in terms of invariants of its homology. These results
specialize to basic theorems in commutative algebra and algebraic topology. One
instance is a common generalization of the equicharacteristic case of the New
Intersection Theorem of Hochster, Peskine, P. Roberts, and Szpiro, concerning
complexes over noetherian commutative rings, and of a theorem of G. Carlsson on
differential graded modules over graded polynomial rings.Comment: 27 pages. Minor changes; mainly stylistic. To appear in Inventiones
Mathematica
Oscillatory Modes of a Prominence-PCTR-Corona Slab Model
Oscillations of magnetic structures in the solar corona have often been
interpreted in terms of magnetohydrodynamic waves. We study the adiabatic
magnetoacoustic modes of a prominence plasma slab with a uniform longitudinal
magnetic field, surrounded by a prominence-corona transition region (PCTR) and
a coronal medium. Considering linear small-amplitude oscillations, the
dispersion relation for the magnetoacoustic slow and fast modes is deduced
assuming evanescent-like perturbations in the coronal medium. In the system
without PCTR, a classification of the oscillatory modes according to the
polarisation of their eigenfunctions is made in order to distinguish modes with
fast-like or slow-like properties. Internal and external slow modes are
governed by the prominence and coronal properties respectively, and fast modes
are mostly dominated by prominence conditions for the observed wavelengths. In
addition, the inclusion of an isothermal PCTR does not substantially influence
the mode frequencies, but new solutions (PCTR slow modes) are present.Comment: Accepted for publication in Solar Physic
Dementia in rural settings: A scoping review exploring the personal experiences of people with dementia and their carers
Rural areas tend to be inhabited by more older people and thus have a higher prevalence of dementia. Combined with lower population densities and more sparse geography, rural areas pose numerous barriers and costs relating to support and resource provision. This may leave people with dementia in rural places at a significant disadvantage, leading to a heavy reliance on informal support networks. The present study explores the personal experiences of people living with dementia and carers living in rural areas, seeking to discover both benefits and challenges, as well as recommendations within the literature for improving the lives of those affected by dementia in rural areas. A scoping review following the framework of Arksey and O'Malley identified 60 studies that describe or discuss the personal experience of dementia (either by the person with dementia or carer), in relation to living in rural or remote geographical areas. Four overarching themes were derived, namely the possible benefits of living in a rural community (supportive rural communities), sources of strength described by people affected by dementia in rural areas (managing and coping), detrimental aspects of living in a rural community (rural community challenges) and difficulties with dementia care services. Three further themes yielded recommendations for improving the experience of dementia in rural areas. This review highlights some potential opportunities related to living in rural areas for people living with dementia. These often come with parallel challenges, reflecting a delicate balance between being well-supported and being in crisis for those living in rural areas. Given the limited access to formal services, supporting people with dementia in rural areas requires input and innovation from the people, organisations and services local to those communities
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