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Characterising errors in airborne laser altimetry data to extract soil roughness
Airborne laser altimetry has the potential to make frequent detailed observations that
are important for many aspects of studying land surface processes. However, the
uncertainties inherent in airborne laser altimetry data have rarely been well measured.
Uncertainty is often specified as generally as 20cm in elevation, and 40cm
planimetric. To better constrain these uncertainties, we present an analysis of several
datasets acquired specifically to study the temporal consistency of laser altimetry data,
and thus assess its operational value. The error budget has three main components,
each with a time regime. For measurements acquired less than 50ms apart, elevations
have a local standard deviation in height of 3.5cm, enabling the local measurement of
surface roughness of the order of 5cm. Points acquired seconds apart acquire an
additional random error due to Differential Geographic Positioning System (DGPS)
fluctuation. Measurements made up to an hour apart show an elevation drift of 7cm
over a half hour. Over months, this drift gives rise to a random elevation offset
between swathes, with an average of 6.4cm. The RMS planimetric error in point
location was derived as 37.4cm. We conclude by considering the consequences of
these uncertainties on the principle application of laser altimetry in the UK, intertidal
zone monitoring
Poor compliance and increased mortality, depression and healthcare costs in patients with congenital adrenal hyperplasia
Objectives To evaluate risks of depression and all-cause mortality, healthcare utilisation costs, and treatment adherence in congenital adrenal hyperplasia (CAH) in the UK. Design and Methods A retrospective, matched-cohort study using UK primary-care data from the Clinical Practice Research Datalink linked to hospital and death-certification data. Patients diagnosed with CAH and having ≥1 corticosteroid prescription were matched 1:10 to reference subjects. Risk of death and lifetime prevalence of depression were compared using Cox regression models. Direct financial costs were estimated for healthcare contacts. Treatment adherence was measured by medical possession ratio (MPR). Results 605 patients with CAH were identified; 562 were matched. 270 CAH patients (2,700 controls) were linkable to death-certificate data, with adjusted hazard ratio for all-cause mortality 5.17 (95%CI 2.81 to 9.50). Mean (SD) age at death in CAH patients was 54.8 (23.9) versus 72.8 (18.0) years in control patients. The prevalence ratio of depression in CAH versus control patients was 1.28 (95%CI 1.13 to 1.45). Mean (SD) annual healthcare costs were higher in CAH than controls: at age 0-6 years, £7,038 (£14,846) versus £2,879 (£13,972, p<0.001); 7-17 years, £3,766 (£7,494) versus £1,232 (£2,451, p<0.001); 18-40 years, £1,539 (£872) versus £1,344 (£1,620, p=0.007); and ≥41 years, £4,204 (£4,863) versus £1,651 (£2,303, p<0.001). Treatment adherence was lowest in adults, with 141 (36%) of 396 eligible patients having an MPR <80%. Conclusions This first analysis of CAH in routine UK healthcare suggests that patients with CAH have increased mortality, depression, and healthcare utilisation, and low treatment adherence
The Spitzer/IRAC Legacy over the GOODS fields: full-depth 3.6, 4.5, 5.8, and 8.0 ÎĽm mosaics and photometry for >9000 galaxies at z 3.5-10 from the GOODS Reionization Era wide-Area Treasury from Spitzer (GREATS)
Large scale structure and cosmolog
Evaluation of <sup>11</sup>C-BU99008, a PET Ligand for the Imidazoline Binding Sites in Rhesus Brain
Improved constraints on the expansion rate of the Universe up to z~1.1 from the spectroscopic evolution of cosmic chronometers
We present new improved constraints on the Hubble parameter H(z) in the
redshift range 0.15 < z < 1.1, obtained from the differential spectroscopic
evolution of early-type galaxies as a function of redshift. We extract a large
sample of early-type galaxies (\sim11000) from several spectroscopic surveys,
spanning almost 8 billion years of cosmic lookback time (0.15 < z < 1.42). We
select the most massive, red elliptical galaxies, passively evolving and
without signature of ongoing star formation. Those galaxies can be used as
standard cosmic chronometers, as firstly proposed by Jimenez & Loeb (2002),
whose differential age evolution as a function of cosmic time directly probes
H(z). We analyze the 4000 {\AA} break (D4000) as a function of redshift, use
stellar population synthesis models to theoretically calibrate the dependence
of the differential age evolution on the differential D4000, and estimate the
Hubble parameter taking into account both statistical and systematical errors.
We provide 8 new measurements of H(z) (see Tab. 4), and determine its change in
H(z) to a precision of 5-12% mapping homogeneously the redshift range up to z
\sim 1.1; for the first time, we place a constraint on H(z) at z \neq 0 with a
precision comparable with the one achieved for the Hubble constant (about 5-6%
at z \sim 0.2), and covered a redshift range (0.5 < z < 0.8) which is crucial
to distinguish many different quintessence cosmologies. These measurements have
been tested to best match a \Lambda CDM model, clearly providing a
statistically robust indication that the Universe is undergoing an accelerated
expansion. This method shows the potentiality to open a new avenue in constrain
a variety of alternative cosmologies, especially when future surveys (e.g.
Euclid) will open the possibility to extend it up to z \sim 2.Comment: 34 pages, 15 figures, 6 tables, published in JCAP. It is a companion
to Moresco et al. (2012b, http://arxiv.org/abs/1201.6658) and Jimenez et al.
(2012, http://arxiv.org/abs/1201.3608). The H(z) data can be downloaded at
http://www.physics-astronomy.unibo.it/en/research/areas/astrophysics/cosmology-with-cosmic-chronometer
Multidimensional Conservation Laws: Overview, Problems, and Perspective
Some of recent important developments are overviewed, several longstanding
open problems are discussed, and a perspective is presented for the
mathematical theory of multidimensional conservation laws. Some basic features
and phenomena of multidimensional hyperbolic conservation laws are revealed,
and some samples of multidimensional systems/models and related important
problems are presented and analyzed with emphasis on the prototypes that have
been solved or may be expected to be solved rigorously at least for some cases.
In particular, multidimensional steady supersonic problems and transonic
problems, shock reflection-diffraction problems, and related effective
nonlinear approaches are analyzed. A theory of divergence-measure vector fields
and related analytical frameworks for the analysis of entropy solutions are
discussed.Comment: 43 pages, 3 figure
How to make complexity look simple? Conveying ecosystems restoration complexity for socio-economic research and public engagement
Ecosystems degradation represents one of the major global challenges at the present time, threating people’s livelihoods and well-being worldwide. Ecosystem restoration therefore seems no longer an option, but an imperative. Restoration challenges are such that a dialogue has begun on the need to re-shape restoration as a science. A critical aspect of that reshaping process is the acceptance that restoration science and practice needs to be coupled with socio-economic research and public engagement. This inescapably means conveying complex ecosystem’s information in a way that is accessible to the wider public. In this paper we take up this challenge with the ultimate aim of contributing to making a step change in science’s contribution to ecosystems restoration practice. Using peatlands as a paradigmatically complex ecosystem, we put in place a transdisciplinary process to articulate a description of the processes and outcomes of restoration that can be understood widely by the public. We provide evidence of the usefulness of the process and tools in addressing four key challenges relevant to restoration of any complex ecosystem: (1) how to represent restoration outcomes; (2) how to establish a restoration reference; (3) how to cope with varying restoration time-lags and (4) how to define spatial units for restoration. This evidence includes the way the process resulted in the creation of materials that are now being used by restoration practitioners for communication with the public and in other research contexts. Our main contribution is of an epistemological nature: while ecosystem services-based approaches have enhanced the integration of academic disciplines and non-specialist knowledge, this has so far only followed one direction (from the biophysical underpinning to the description of ecosystem services and their appreciation by the public). We propose that it is the mix of approaches and epistemological directions (including from the public to the biophysical parameters) what will make a definitive contribution to restoration practice
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