463 research outputs found
A low-cost and open-source approach for supraglacial debris thickness mapping using UAV-based infrared thermography
Debris-covered glaciers exist in many mountain ranges and play an important role in the regional water cycle. However, modelling the surface mass balance, runoff contribution and future evolution of debris-covered glaciers is fraught with uncertainty as accurate observations on small-scale variations in debris thickness and sub-debris ice melt rates are only available for a few locations worldwide. Here we describe a customised low-cost unoccupied aerial vehicle (UAV) for high-resolution thermal imaging of mountain glaciers and present a complete open-source pipeline that facilitates the generation of accurate surface temperature and debris thickness maps from radiometric images. First, a radiometric orthophoto is computed from individual radiometric UAV images using structure-from-motion and multi-view-stereo techniques. User-specific calibration and correction procedures can then be applied to the radiometric orthophoto to account for atmospheric and environmental influences that affect the radiometric measurement. The thermal orthophoto reveals distinct spatial variations in surface temperature across the surveyed debris-covered area. Finally, a high-resolution debris thickness map is derived from the corrected thermal orthophoto using an empirical or inverse surface energy balance model that relates surface temperature to debris thickness and is calibrated against in situ measurements. Our results from a small-scale experiment on the Kanderfirn (also known as Kander Neve) in the Swiss Alps show that the surface temperature and thickness of a relatively thin debris layer (ca. 0â15âcm) can be mapped with high accuracy using an empirical or physical model. On snow and ice surfaces, the mean deviation of the mapped surface temperature from the melting point (âŒâ0ââC) was 0.6â±â2.0ââC. The root-mean-square error of the modelled debris thickness was 1.3âcm. Through the detailed mapping, typical small-scale debris features and debris thickness patterns become visible, which are not spatially resolved by the thermal infrared sensors of current-generation satellites. The presented approach paves the way for comprehensive high-resolution supraglacial debris thickness mapping and opens up new opportunities for more accurate monitoring and modelling of debris-covered glaciers.</p
Towards human-level performance on automatic pose estimation of infant spontaneous movements
Assessment of spontaneous movements can predict the long-term developmental
disorders in high-risk infants. In order to develop algorithms for automated
prediction of later disorders, highly precise localization of segments and
joints by infant pose estimation is required. Four types of convolutional
neural networks were trained and evaluated on a novel infant pose dataset,
covering the large variation in 1 424 videos from a clinical international
community. The localization performance of the networks was evaluated as the
deviation between the estimated keypoint positions and human expert
annotations. The computational efficiency was also assessed to determine the
feasibility of the neural networks in clinical practice. The best performing
neural network had a similar localization error to the inter-rater spread of
human expert annotations, while still operating efficiently. Overall, the
results of our study show that pose estimation of infant spontaneous movements
has a great potential to support research initiatives on early detection of
developmental disorders in children with perinatal brain injuries by
quantifying infant movements from video recordings with human-level
performance.Comment: Published in Computerized Medical Imaging and Graphics (CMIG
A first attempt to model region-wide glacier surface mass balances in the Karakoram: findings and future challenges
In contrast to the central and eastern part of High Mountain Asia (HMA), no extensive glacier mass loss has been observed in the Karakoram during previous decades. However, the potential meteorological and glaciological causes of the so-called Karakoram Anomaly are diverse and still under debate. This paper introduces and presents a novel glacier Surface Mass Balance Model (glacierSMBM) to test whether the characteristic regional mass balance pattern can be reproduced using recent field, remote-sensing and reanalysis data as input. A major advantage of the model setup is the implementation of the non-linear effect of supra-glacial debris on the sub-surface ice melt. In addition to a first assessment of the annual surface mass balance from 1st August 2010 until 31st July 2011, a sensitivity analysis was performed to investigate the response of Karakoram glaciers to recent climate change. The mean modelled glacier mass balance for the Karakoram during the observation period is -0.92 m water equivalent (w.e.) a-1 and corresponds to an annual melt water contribution of ~12.66 km3. Data inaccuracies and the neglected process of snow redistribution from adjacent slopes are probably responsible for the bias in the model output. Despite the general offset between mass gain and mass loss, the model captures the characteristic features of the anomaly and indicates that positive glacier mass balances are mainly restricted to the central and northeastern part of the mountain range. From the evaluation of the sensitivity analysis, it can be concluded that the complex glacier response in the Karakoram is not the result of a single driver, but related to a variety of regional peculiarities such as the favourable meteorological conditions, the extensive supra-glacial debris and the timing of the main precipitation season
Synaptic inhibition in the lateral habenula shapes reward anticipation
The lateral habenula (LHb) supports learning processes enabling the prediction of upcoming rewards. While reward-related stimuli decrease the activity of LHb neurons, whether this anchors on synaptic inhibition to guide reward-driven behaviors remains poorly understood. Here, we combine in vivo two-photon calcium imaging with Pavlovian conditioning in mice and report that anticipatory licking emerges along with decreases in cue-evoked calcium signals in individual LHb neurons. In vivo multiunit recordings and pharmacology reveal that the cue-evoked reduction in LHb neuronal firing relies on GABAA-receptor activation. In parallel, we observe a postsynaptic potentiation of GABAA-receptor-mediated inhibition, but not excitation, onto LHb neurons together with the establishment of anticipatory licking. Finally, strengthening or weakening postsynaptic inhibition with optogenetics and GABAA-receptor manipulations enhances or reduces anticipatory licking, respectively. Hence, synaptic inhibition in the LHb shapes reward anticipation.
Keywords: GABA(A) receptors; cue-reward associative behavior; lateral habenula; synaptic inhibition; synaptic plasticit
Distributed global debris thickness estimates reveal debris significantly impacts glacier mass balance
International audienc
Effects of a clinical decision support system and patient portal for preventing medication-related falls in older fallers:Protocol of a cluster randomized controlled trial with embedded process and economic evaluations (ADFICE_IT)
BackgroundFalls are the leading cause of injury-related mortality and hospitalization among adults aged â„ 65 years. An important modifiable fall-risk factor is use of fall-risk increasing drugs (FRIDs). However, deprescribing is not always attempted or performed successfully. The ADFICE_IT trial evaluates the combined use of a clinical decision support system (CDSS) and a patient portal for optimizing the deprescribing of FRIDs in older fallers. The intervention aims to optimize and enhance shared decision making (SDM) and consequently prevent injurious falls and reduce healthcare-related costs.MethodsA multicenter, cluster-randomized controlled trial with process evaluation will be conducted among hospitals in the Netherlands. We aim to include 856 individuals aged â„ 65 years that visit the falls clinic due to a fall. The intervention comprises the combined use of a CDSS and a patient portal. The CDSS provides guideline-based advice with regard to deprescribing and an individual fall-risk estimation, as calculated by an embedded prediction model. The patient portal provides educational information and a summary of the patientâs consultation. Hospitals in the control arm will provide care-as-usual. Fall-calendars will be used for measuring the time to first injurious fall (primary outcome) and secondary fall outcomes during one year. Other measurements will be conducted at baseline, 3, 6, and 12 months and include quality of life, cost-effectiveness, feasibility, and shared decision-making measures. Data will be analyzed according to the intention-to-treat principle. Difference in time to injurious fall between the intervention and control group will be analyzed using multilevel Cox regression.DiscussionThe findings of this study will add valuable insights about how digital health informatics tools that target physicians and older adults can optimize deprescribing and support SDM. We expect the CDSS and patient portal to aid in deprescribing of FRIDs, resulting in a reduction in falls and related injuries
Quantitative trait loci conferring grain mineral nutrient concentrations in durum wheat 3 wild emmer wheat RIL population
Mineral nutrient malnutrition, and particularly
deficiency in zinc and iron, afflicts over 3 billion people
worldwide. Wild emmer wheat, Triticum turgidum ssp.
dicoccoides, genepool harbors a rich allelic repertoire for
mineral nutrients in the grain. The genetic and physiological
basis of grain protein, micronutrients (zinc, iron,
copper and manganese) and macronutrients (calcium,
magnesium, potassium, phosphorus and sulfur) concentration
was studied in tetraploid wheat population of 152
recombinant inbred lines (RILs), derived from a cross
between durum wheat (cv. Langdon) and wild emmer
(accession G18-16). Wide genetic variation was found
among the RILs for all grain minerals, with considerable
transgressive effect. A total of 82 QTLs were mapped for
10 minerals with LOD score range of 3.2â16.7. Most QTLs
were in favor of the wild allele (50 QTLs). Fourteen pairs
of QTLs for the same trait were mapped to seemingly
homoeologous positions, reflecting synteny between the A
and B genomes. Significant positive correlation was found
between grain protein concentration (GPC), Zn, Fe and Cu,
which was supported by significant overlap between the
respective QTLs, suggesting common physiological and/or
genetic factors controlling the concentrations of these
mineral nutrients. Few genomic regions (chromosomes 2A,
5A, 6B and 7A) were found to harbor clusters of QTLs for
GPC and other nutrients. These identified QTLs may
facilitate the use of wild alleles for improving grain
nutritional quality of elite wheat cultivars, especially in
terms of protein, Zn and Fe
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