16 research outputs found
Terrestrial laser scanning for plot-scale forest measurement
Plot-scale measurements have been the foundation
for forest surveys and reporting for over 200 years. Through
recent integration with airborne and satellite remote sensing, manual measurements of vegetation structure at the plot scale are now the basis for landscape, continental and international mapping of our forest resources. The use of terrestrial laser scanning (TLS) for plot-scale measurement was first demonstrated over a decade ago, with the intimation that these instruments could replace manual measurement methods. This has not yet been the case, despite the unparalleled structural information that TLS can capture. For TLS to reach its full potential, these instruments cannot be viewed as a logical progression of existing plot-based measurement. TLS must be viewed as a disruptive technology that requires a rethink of vegetation surveys and their application across a wide range
of disciplines. We review the development of TLS as a plotscale measurement tool, including the evolution of both instrument hardware and key data processing methodologies.
We highlight two broad data modelling approaches of gap
probability and geometrical modelling and the basic theory
that underpins these. Finally, we discuss the future prospects for increasing the utilisation of TLS for plot-scale forest assessment and forest monitoring
Improved functionalization of oleic acid-coated iron oxide nanoparticles for biomedical applications
Superparamagnetic iron oxide nanoparticles
can providemultiple benefits for biomedical applications
in aqueous environments such asmagnetic separation or
magnetic resonance imaging. To increase the colloidal
stability and allow subsequent reactions, the introduction
of hydrophilic functional groups onto the particles’
surface is essential. During this process, the original
coating is exchanged by preferably covalently bonded
ligands such as trialkoxysilanes. The duration of the
silane exchange reaction, which commonly takes more
than 24 h, is an important drawback for this approach. In
this paper, we present a novel method, which introduces
ultrasonication as an energy source to dramatically
accelerate this process, resulting in high-quality waterdispersible nanoparticles around 10 nmin size. To prove
the generic character, different functional groups were
introduced on the surface including polyethylene glycol
chains, carboxylic acid, amine, and thiol groups. Their
colloidal stability in various aqueous buffer solutions as
well as human plasma and serum was investigated to
allow implementation in biomedical and sensing
applications.status: publishe
Insights into the Digital Recovery of the Scythica Vindobonensia
The article provides insights into the digital recovery of the Scythica Vindobonensia, the new fragments on Gothic incursions into Roman provinces in the Balkans in the 3rd century AD, which were discovered some years ago in four palimpsest folios of the Greek manuscript Hist. gr. 73 of the Austrian National Library in Vienna. The fragments come most probably from the lost work Scythica by the 3rd-century historian Dexippus of Athens. In order to render the palimpsested writing of the 11th-century copy of the ancient text visible, the involved scholars invited several technical and scientific teams who provide state-of-the-art expertise in the field of digital recovery of erased writings to apply non-invasive imaging and advanced image processing on the Vienna palimpsest
Comparison of levetiracetam and controlled-release carbamazepine in newly diagnosed epilepsy
We report the results of a prospective study of the efficacy and tolerability of levetiracetam, a new antiepileptic drug with a unique mechanism of action, in comparison with controlled-release carbamazepine as first treatment in newly diagnosed epilepsy.Adults with > or =2 partial or generalized tonic-clonic seizures in the previous year were randomly assigned to levetiracetam (500 mg twice daily, n = 288) or controlled-release carbamazepine (200 mg twice daily, n = 291) in a multicenter, double-blind, noninferiority, parallel-group trial. If a seizure occurred within 26 weeks of stabilization, dosage was increased incrementally to a maximum of levetiracetam 1,500 mg twice daily or carbamazepine 600 mg twice daily. Patients achieving the primary endpoint (6-month seizure freedom) continued on treatment for a further 6-month maintenance period.At per-protocol analysis, 73.0\% (56.6\%) of patients randomized to levetiracetam and 72.8\% (58.5\%) receiving controlled-release carbamazepine were seizure free at the last evaluated dose (adjusted absolute difference 0.2\%, 95\% CI -7.8\% to 8.2\%) for > or =6 months (1 year). Of all patients achieving 6-month (1-year) remission, 80.1\% (86.0\%) in the levetiracetam group and 85.4\% (89.3\%) in the carbamazepine group did so at the lowest dose level. Withdrawal rates for adverse events were 14.4\% with levetiracetam and 19.2\% with carbamazepine.Levetiracetam and controlled-release carbamazepine produced equivalent seizure freedom rates in newly diagnosed epilepsy at optimal dosing in a setting mimicking clinical practice. This trial has confirmed in a randomized, double-blind setting previously uncontrolled observations that most people with epilepsy will respond to their first-ever antiepileptic drug at low dosage
ECOSTRESS : NASA's next generation mission to measure evapotranspiration from the international space station
The ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) was launched to the International Space Station on 29 June 2018 by the National Aeronautics and Space Administration (NASA). The primary science focus of ECOSTRESS is centered on evapotranspiration (ET), which is produced as Level-3 (L3) latent heat flux (LE) data products. These data are generated from the Level-2 land surface temperature and emissivity product (L2_LSTE), in conjunction with ancillary surface and atmospheric data. Here, we provide the first validation (Stage 1, preliminary) of the global ECOSTRESS clear-sky ET product (L3_ET_PT-JPL, Version 6.0) against LE measurements at 82 eddy covariance sites around the world. Overall, the ECOSTRESS ET product performs well against the site measurements (clear-sky instantaneous/time of overpass: r(2) = 0.88; overall bias = 8%; normalized root-mean-square error, RMSE = 6%). ET uncertainty was generally consistent across climate zones, biome types, and times of day (ECOSTRESS samples the diurnal cycle), though temperate sites are overrepresented. The 70-m-high spatial resolution of ECOSTRESS improved correlations by 85%, and RMSE by 62%, relative to 1-km pixels. This paper serves as a reference for the ECOSTRESS L3 ET accuracy and Stage 1 validation status for subsequent science that follows using these data. Key Points ECOSTRESS is a state-of-the-art combination of thermal bands, spatial and temporal resolutions, and measurement accuracy and precision Data from 82 eddy covariance sites were coalesced concurrently with the first year of ECOSTRESS for Stage 1 validation Clear-sky ET from ECOSTRESS compared well against a wide range of eddy covariance sites, vegetation classes, climate zones, and times of da