3,951 research outputs found
On Generalized Additive Models for Representation of Solar EUV Irradiance
In the context of space weather forecasting, solar EUV irradiance specification is needed on multiple time scales, with associated uncertainty quantification for determining the accuracy of downstream parameters. Empirical models of irradiance often rely on parametric fits between irradiance in several bands and various solar indices. We build upon these empirical models by using Generalized Additive Models (GAMs) to represent solar irradiance. We apply the GAM approach in two steps: (a) A GAM is fitted between FISM2 irradiance and solar indices F10.7, Revised Sunspot Number, and the Lyman-α solar index. (b) A second GAM is fit to model the residuals of the first GAM with respect to FISM2 irradiance. We evaluate the performance of this approach during Solar Cycle 24 using GAMs driven by known solar indices as well as those forecasted 3 days ahead with an autoregressive modeling approach. We demonstrate negligible dependence of performance on solar cycle and season, and we assess the efficacy of the GAM approach across different wavelengths
Rapportâbuilding in multiple interviews of children
AbstractRapportâbuilding is key in child investigative interviews, however, recommendations of how to build rapport differ. Additionally, rapport in more complex situations: when a child is interviewed repeatedly or requires separate rapport building have not been studied. This research examined the UK's âAchieving Best Evidenceâ guidelines for rapportâbuilding, which recommend conducting a neutral discussion, compared with a control condition and a separate rapportâbuilding session for first interviews on children's recall and wellâbeing (measured by state anxiety and rapport questionnaires). For second and third interviews, additional full rapportâbuilding sessions were compared to shortened or no rapportâbuilding conditions. No significant differences in children's (N = 107) recall or wellâbeing were found across rapportâbuilding conditions for all interviews. We conclude that for children who have experienced nonâtraumatic events, the inclusion of a neutral discussion rapportâbuilding phase may not be any more beneficial for children than conducting a friendly interview
Social flocculation in plantâanimal worms
Individual animals can often move more safely or more efficiently as members of a group. This can be as simple as safety in numbers or as sophisticated as aerodynamic or hydrodynamic cooperation. Here, we show that individual plantâanimal worms (Symsagittifera roscoffensis) can move to safety more quickly through flocculation. Flocs form in response to turbulence that might otherwise carry these beach-dwelling worms out to sea. They allow the worms to descend much more quickly to the safety of the substrate than single worms could swim. Descent speed increases with floc size such that larger flocs can catch up with smaller ones and engulf them to become even larger and faster. To our knowledge, this is the first demonstration of social flocculation in a wild, multicellular organism. It is also remarkable that such effective flocculation occurs where the components are comparatively large multicellular organisms organized as entangled ensembles
Experiences of providing self-management support: a qualitative study of pre-registration physiotherapy students at one university
BACKGROUND: The importance of health care professionals in supporting self-management of individuals with long-term conditions has increased significantly over the last decade. While research has explored health care professionalsâ experiences of supporting self-management, there is a paucity of literature exploring student experiences.
OBJECTIVE: The aim of this study was to explore pre-registration physiotherapy studentsâ experiences, of using self-management support principles in practice.
METHODS: A qualitative methodology was adopted, in which final year pre-registration physiotherapy students, were invited to participate in focus groups to explore their experiences of using self-management principles with patients in practice. Interviews were transcribed verbatim and analysed using thematic analysis.
RESULTS: Four main themes were identified: i) self-management support as something to apply or do, ii) environmental and patient factors influencing application in practice, iii) limited development of self-management support self-efficacy and iv) learning experiences of self-management support disjointed. Despite self-management support teaching, students had varied theoretical comprehension of the concepts and overall lacked confidence in the practical application
CONCLUSIONS: The findings suggest more consistent and practical approaches would support learning and facilitate the development of studentsâ self-efficacy for using self-management support principles. For instance, curricula should encompass opportunities to explore simulated scenarios to develop effective collaborative communication with individuals and avoid didactic and directive approaches to providing self-management support. Further research is planned to investigate studentsâ experiences of a newly validated curriculum where self-management support teaching is integrated and embedded. Research to compare communication curriculum and effectiveness between universities is also warranted
Laser cooling of a nanomechanical resonator mode to its quantum ground state
We show that it is possible to cool a nanomechanical resonator mode to its
ground state. The proposed technique is based on resonant laser excitation of a
phonon sideband of an embedded quantum dot. The strength of the sideband
coupling is determined directly by the difference between the electron-phonon
couplings of the initial and final states of the quantum dot optical
transition. Possible applications of the technique we describe include
generation of non-classical states of mechanical motion.Comment: 5 pages, 3 figures, revtex
Photochemistry in the arctic free troposphere: Ozone budget and its dependence on nitrogen oxides and the production rate of free radicals
Abstract. Local ozone production and loss rates for the arctic free troposphere (58â85 ⊠N, 1â6 km, FebruaryâMay) during the Tropospheric Ozone Production about the Spring Equinox (TOPSE) campaign were calculated using a constrained photochemical box model. Estimates were made to assess the importance of local photochemical ozone production relative to transport in accounting for the springtime maximum in arctic free tropospheric ozone. Ozone production and loss rates from our diel steady-state box model constrained by median observations were first compared to two point box models, one run to instantaneous steady-state and the other run to diel steady-state. A consistent picture of local ozone photochemistry was derived by all three box models suggesting that differences between the approaches were not critical. Our model-derived ozone production rates increased by a factor of 28 in the 1â3 km layer and a factor of 7 in the 3â6 km layer between February and May. The arctic ozone budget required net import of ozone into the arctic free troposphere throughout the campaign; however, the transport term exceeded the photochemical production only in the lower free troposphere (1â3 km) between February and March. Gross ozone production rates were calculated to increase linearly with NOx mixing ratios up to âŒ300 pptv in February and for NOx mixing ratio
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Coupled evolution of BrOx-ClOx-HOx-NOx chemistry during bromine-catalyzed ozone depletion events in the arctic boundary layer
Extensive chemical characterization of ozone (O3) depletion events in the Arctic boundary layer during the TOPSE aircraft mission in March-May 2000 enables analysis of the coupled chemical evolution of bromine (BrOx), chlorine (ClOx), hydrogen oxide (HOx) and nitrogen oxide (NOx) radicals during these events. We project the TOPSE observations onto an O3 chemical coordinate to construct a chronology of radical chemistry during O3 depletion events, and we compare this chronology to results from a photochemical model simulation. Comparison of observed trends in ethyne (oxidized by Br) and ethane (oxidized by Cl) indicates that ClOx chemistry is only active during the early stage Of O3 depletion (O3 > 10 ppbv). We attribute this result to the suppression of BrCl regeneration as O3 decreases. Formaldehyde and peroxy radical concentrations decline by factors of 4 and 2 respectively during O3 depletion and we explain both trends on the basis of the reaction of CH2O with Br. Observed NOx concentrations decline abruptly in the early stages Of O3 depletion and recover as O3 drops below 10 ppbv. We attribute the initial decline to BrNO3 hydrolysis in aerosol, and the subsequent recovery to suppression of BrNO3 formation as O3 drops. Under halogen-free conditions we find that HNO4 heterogeneous chemistry could provide a major NOx sink not included in standard models. Halogen radical chemistry in the model can produce under realistic conditions an oscillatory system with a period of 3 days, which we believe is the fastest oscillation ever reported for a chemical system in the atmosphere
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