954 research outputs found
Texture zeros and hierarchical masses from flavour (mis)alignment
We introduce an unconventional interpretation of the fermion mass matrix
elements. As the full rotational freedom of the gauge-kinetic terms renders a
set of infinite bases called weak bases, basis-dependent structures as mass
matrices are unphysical. Matrix invariants, on the other hand, provide a set of
basis-independent objects which are of more relevance. We employ one of these
invariants to give a new parametrization of the mass matrices. By virtue of it,
one gains control over its implicit implications on several mass matrix
structures. The key element is the trace invariant which resembles the equation
of a hypersphere with a radius equal to the Frobenius norm of the mass matrix.
With the concepts of alignment or misalignment we can identify texture zeros
with certain alignments whereas Froggatt-Nielsen structures in the matrix
elements are governed by misalignment. This method allows further insights of
traditional approaches to the underlying flavour geometry.Comment: 27 pages; v2 matches version accepted by NPB, discussion on Dirac CP
phase for neutrinos adde
Vibrating soap films: An analog for quantum chaos on billiards
We present an experimental setup based on the normal modes of vibrating soap
films which shows quantum features of integrable and chaotic billiards. In
particular, we obtain the so-called scars -narrow linear regions with high
probability along classical periodic orbits- for the classically chaotic
billiards. We show that these scars are also visible at low frequencies.
Finally, we suggest some applications of our experimental setup in other
related two-dimensional wave phenomena.Comment: 5 pages, 7 figures. Better Postscript figures available on reques
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Chilean wildfires: probabilistic prediction, emergency response and public communication
The 2016/17 wildfire season in Chile was the worst on record, burning more than 600,000 hectares. Whilst wildfires are an important natural process in some areas of Chile supporting its diverse ecosystems, wildfires are also one of the biggest threats to Chile’s unique biodiversity and it’s timber and wine industries. They also pose a danger to human life and property due to the sharp wildland-urban interface that exists in many Chilean towns and cities. Wildfires are however difficult to predict due to the combination of physical (meteorology, vegetation and fuel condition), and human (population density and awareness level) factors. Most Chilean wildfires are started due to accidental ignition by humans. This accidental ignition could be minimized if an effective wildfire warning system alerted the population to the heightened danger of wildfires in certain locations and meteorological conditions. Here we demonstrate the design of a novel probabilistic wildfire prediction system. The system uses ensemble forecast meteorological data together with a longtime series of fire products derived from Earth Observation to predict not only fire occurrence, but in addition, how intense wildfires could be. The system provides wildfire risk estimation and associated uncertainty for up to 6 days in advance, and communicates it to a variety of end users. The advantage of this probabilistic wildfire warning system over deterministic systems is that it allows users to assess the confidence of a forecast and thus make more informed decisions regarding resource allocation and forest management. The approach used in this study could easily be adapted to communicate other probabilistic forecasts of natural hazards
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Reporting on novel complex intervention development for adults with social communication impairments after acquired brain injury
Purpose: Interventions are often poorly described in published controlled trials, with relatively little information regarding intervention development, content and fidelity. This makes it difficult to conduct replication studies, interpret and compare findings across studies and for therapists to deliver the intervention in clinical practice. Complete reporting of interventions (including fidelity) is now recommended for treatment studies, and this standardised approach is achieved using the Template for Intervention Description and Replication (TIDieR). The aim of this paper is to describe the multi-phase process of developing a novel intervention for adults with acquired brain injury (ABI), and report on the findings from involving practicing therapists in this process.
Methods: Phase 1 involved a review of relevant literature and specifying the intervention as a prototype intervention manual. Phase 2 comprised a focus group with eight practicing therapists exploring their experiences and perceptions of the intervention, potential active components, and essential elements; it also included review of the prototype manual. Data from the focus group discussion was transcribed and analysed thematically. Phase 3 investigated actual fidelity of the intervention undertaken, achieved by observers viewing videoed sessions and appraising against the fidelity checklist, which was then analysed using Cohen’s kappa.
Results: Project-based intervention was defined as having six essential elements: a project or tangible end product focus; group-based intervention; individualised communication-based goals; communication partner involvement; acknowledgement and support of participants’ cognitive ability; and consideration and plan to address impaired awareness. Analysis of focus group data revealed four themes of essential elements; group context; therapeutic skills; and manual core components and informed the development of a fidelity checklist with 13 essential and 6 desirable criteria. Fidelity assessed using percent agreement was acceptable for almost all rater pairs; where significant, Kappa coefficients had values ranging from poor to excellent (k=0.34 – 1.0) depending on rater pair and session.
Discussion: The TIDieR framework provided a clear systematic approach for the complete description and reporting of a complex communication intervention for people with ABI. This paper comprehensively described the development and manualisation of an intervention in collaboration with practicing therapists which can be used for future testing. In addition, the process undertaken has the potential to inform rehabilitation researchers in other fields on the development of complex interventions
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Examining the New Phenomenon of Teachers as Brand Ambassadors
A brand ambassador receives some form of compensation or perk in exchange for the endorsement of a product. This research brief explores the ethical, legal, and policy issues associated with the hiring of teachers as brand ambassadors, a new and disturbing foray into corporate marketing within schools. It examines the potential benefits that these corporate-teacher relationships provide to teachers and their students, and weighs these against the potential concerns, conflicts, and costs. It considers the need for protections of students’ interests as teacher brand ambassadorships grow as a presence in public schools, and provides recommendations for future policy-making.</p
Land Surface Processes Analysis Using Sentinel-3 OLCI and Modis Data
This communication describes the optical processing chain to use Sentinel-3 OLCI and MODIS data as part of the ESA funded Synergy project of the Scientific Exploitation of Sentinel Missions (SEOM) component of the EO Envelope programme. One of the goals of the project is to use Data Assimilation techniques to produce land surface products combining the data from Sentinels-2 and 3. Some of the derived products are the OLCI atmospherically corrected data that can be used to generate a spectral BRDF product from OLCI and MODIS, broadband albedo and different vegetation parameters. The project also implements a series of efficiency improvements to the algorithms to speed up the processing. The demonstrator product uses one year of OLCI and MODIS data (2017)
A new derivation of the Hubble constant from -ray attenuation using improved optical depths for the Fermi and CTA era
We present -ray optical-depth calculations from a recently published
extragalactic background light (EBL) model built from multiwavelength galaxy
data from the Hubble Space Telescope Cosmic Assembly Near-Infrared Deep
Extragalactic Legacy Survey (HST/CANDELS). CANDELS gathers one of the deepest
and most complete observations of stellar and dust emissions in galaxies. This
model resulted in a robust derivation of the evolving EBL spectral energy
distribution up to , including the far-infrared peak. Therefore, the
optical depths derived from this model will be useful for determining the
attenuation of -ray photons coming from high-redshift sources, such as
those detected by the Large Area Telescope on board the Fermi Gamma-ray Space
Telescope, and for multi-TeV photons that will be detected from nearby sources
by the future Cherenkov Telescope Array. From these newly calculated optical
depths, we derive the cosmic -ray horizon and also measure the
expansion rate and matter content of the Universe including an assessment of
the impact of the EBL uncertainties. We find km
s Mpc when fixing , and
km s Mpc and , when
exploring these two parameters simultaneously.Comment: 11 pages, 8 figures, 1 tables; Accepted by MNRA
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