3,053 research outputs found
Translucent windows: How uncertainty in competitive interactions impacts detection of community pattern
Trait variation and similarity among coexisting species can provide a window
into the mechanisms that maintain their coexistence. Recent theoretical
explorations suggest that competitive interactions will lead to groups, or
clusters, of species with similar traits. However, theoretical predictions
typically assume complete knowledge of the map between competition and measured
traits. These assumptions limit the plausible application of these patterns for
inferring competitive interactions in nature. Here we relax these restrictions
and find that the clustering pattern is robust to contributions of unknown or
unobserved niche axes. However, it may not be visible unless measured traits
are close proxies for niche strategies. We conclude that patterns along single
niche axes may reveal properties of interspecific competition in nature, but
detecting these patterns requires natural history expertise firmly tying traits
to niches.Comment: Main text: 18 pages, 6 figures. Appendices: A-G, 6 supplementary
figures. This is the peer reviewed version of the article of the same title
which has been accepted for publication at Ecology Letters. This article may
be used for non-commercial purposes in accordance with Wiley Terms and
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The Collaborative Development of New CFD Methods Adapted for Tilt Rotor Aircraft in the HiPerTilt Project
No abstract available
Genomics knowledge and attitudes among European public health professionals. Results of a cross-sectional survey
Background The international public health (PH) community is debating the opportunity to incorporate genomic technologies into PH practice. A survey was conducted to assess attitudes of the European Public Health Association (EUPHA) members towards their role in the implementation of public health genomics (PHG), and their knowledge and attitudes towards genetic testing and the delivery of genetic services. Methods EUPHA members were invited via monthly newsletter and e-mail to take part in an online survey from February 2017 to January 2018. A descriptive analysis of knowledge and attitudes was conducted, along with a univariate and multivariate analysis of their determinants. Results Five hundred and two people completed the questionnaire, 17.9% were involved in PHG activities. Only 28.9% correctly identified all medical conditions for which there is (or not) evidence for implementing genetic testing; over 60% thought that investing in genomics may divert economic resources from social and environmental determinants of health. The majority agreed that PH professionals may play different roles in incorporating genomics into their activities. Better knowledge was associated with positive attitudes towards the use of genetic testing and the delivery of genetic services in PH (OR = 1.48; 95% CI 1.01–2.18). Conclusions Our study revealed quite positive attitudes, but also a need to increase awareness on genomics among European PH professionals. Those directly involved in PHG activities tend to have a more positive attitude and better knowledge; however, gaps are also evident in this group, suggesting the need to harmonize practice and encourage greater exchange of knowledge among professionals
Minimal length in quantum space and integrations of the line element in Noncommutative Geometry
We question the emergence of a minimal length in quantum spacetime, comparing
two notions that appeared at various points in the literature: on the one side,
the quantum length as the spectrum of an operator L in the Doplicher
Fredenhagen Roberts (DFR) quantum spacetime, as well as in the canonical
noncommutative spacetime; on the other side, Connes' spectral distance in
noncommutative geometry. Although on the Euclidean space the two notions merge
into the one of geodesic distance, they yield distinct results in the
noncommutative framework. In particular on the Moyal plane, the quantum length
is bounded above from zero while the spectral distance can take any real
positive value, including infinity. We show how to solve this discrepancy by
doubling the spectral triple. This leads us to introduce a modified quantum
length d'_L, which coincides exactly with the spectral distance d_D on the set
of states of optimal localization. On the set of eigenstates of the quantum
harmonic oscillator - together with their translations - d'_L and d_D coincide
asymptotically, both in the high energy and large translation limits. At small
energy, we interpret the discrepancy between d'_L and d_D as two distinct ways
of integrating the line element on a quantum space. This leads us to propose an
equation for a geodesic on the Moyal plane.Comment: 29 pages, 2 figures. Minor corrections to match the published versio
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Correlations between FEV1 and patient-reported outcomes: A pooled analysis of 23 clinical trials in patients with chronic obstructive pulmonary disease.
BACKGROUND: In clinical trials of inhaled bronchodilators, chronic obstructive pulmonary disease (COPD) guidelines recommend that patient-reported outcomes (PROs) are assessed alongside lung function. How these endpoints are related is unclear. METHODS: Pooled longitudinal data from 23 randomised controlled COPD studies were analyzed (N = 23,213). Treatments included long-acting β2 agonists, long-acting muscarinic antagonists (LABAs or LAMAs) and the LABA/LAMA combination QVA149. Outcome measures were Transition Dyspnoea Index (TDI) and St. George's Respiratory Questionnaire (SGRQ) scores, COPD exacerbation frequency and rescue medication use. Relationships between changes in trough forced expiratory volume in one second (ΔFEV1) and outcomes following treatment were assessed using correlations of data summaries and model-based analysis: generalized linear mixed-effect regression modeling to determine if ΔFEV1 could predict patient outcomes with different treatments. RESULTS: Mean age was 64 years, 73% were male, and most had moderate (45%) or severe (52%) disease. Statistically significant correlations were observed between ΔFEV1 and each outcome measure (exacerbations Rs = 0.05; rescue medication, SGRQ, TDI, r = 0.11-0.16; all p < .001). Patients with greater improvements in trough FEV1 had on average better SGRQ and TDI scores, fewer exacerbations, and used less rescue medication. For SGRQ and TDI scores, minimal clinically important differences were observed over the range of pooled ΔFEV1 values. Model-based predictions confirmed the treatment effect was partly explained by changes in FEV1 from baseline with improvements in PROs observed across all treatments when trough FEV1 improved. Across all endpoints active treatments were better than placebo (p < .0001), and LABA/LAMA treatment resulted in numerically better treatment outcomes than either monocomponent. CONCLUSIONS: These data suggest that FEV1 improvements post-bronchodilation correlate with PRO improvements. Further improvements in patient outcomes may be expected by maximizing lung function improvements. TRIAL REGISTRATION: Registration details for the 23 randomised controlled studies used in this pooled analysis are supplied in Additional File 4
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