The ability of a forest to buffer understory temperature extremes depends on the canopy structure, which is often measured from the ground. However, ground measurements provide only point estimates, ...which cannot be used for spatially explicit microclimate modeling. Canopy structures derived from airborne light detection and ranging (LiDAR) can overcome these limitations, but high point-density LiDAR is expensive and computationally challenging. Therefore, we explored whether unmanned aerial systems (UAS) processed with the structure-from-motion (SfM) algorithm could serve as an alternative source of canopy variables for forest microclimate modeling. Specifically, we compared the performance of the canopy cover and height derived from the ground measurements and passive (UAS-SfM) and active (UAS-LiDAR) remote sensing as predictors of air and soil temperature offsets (i.e. differences between the forest understory and treeless areas).
We found that the maximum air temperatures were substantially lower inside than outside the forest, with differences ranging from 9.0 to 12.5 °C. The soil temperatures under the canopy were also reduced, but the soil temperature offsets were lower and ranged from 1.1 to 2.8 °C. The air and soil temperature offsets both increased with increasing tree height and canopy cover. However, the prediction ability of tree height and canopy cover differed if they were ground-based or remotely sensed. The remotely sensed canopy indices explained air temperature offsets better (UAS-SfM: R2 = 0.59, RMSE = 0.75 °C; UAS-LiDAR: R2 = 0.57, RMSE = 0.76 °C) than ground measurements (R2 = 0.51, RMSE = 0.80 °C). Ground-based metrics explained soil temperature offsets better (R2 = 0.37, RMSE = 0.36 °C) than passive remote sensing approach (UAS-SfM: R2 = 0.27, RMSE = 0.39 °C), but comparably to active one (UAS-LiDAR: R2 = 0.35, RMSE = 0.37 °C).
Our results suggest that both UAS-SfM and UAS-LiDAR can substitute ground canopy measurements for air temperature modeling, but soil temperature modeling is more challenging. Overall, our results show that forest microclimate can be modelled at a very high spatial resolution using UAS equipped with inexpensive optical cameras. The increasingly available UAS-SfM approach can thus provide fine-resolution microclimatic data much needed for biologically relevant predictions of species responses to climate change.
•Forest temperature buffering increases with increasing canopy cover and tree height.•UAS remote sensing explains air temperature buffering better than ground measurements.•UAS-SfM predicts air temperature buffering as well as UAS-LiDAR.
Urban greenery plays an important role in reducing air pollution, being one of the often-used, nature-based measures in sustainable and climate-resilient urban development. However, when modelling ...its effect on air pollution removal by dry deposition, coarse and time-limited data on vegetation properties are often included, disregarding the high spatial and temporal heterogeneity in urban forest canopies. Here, we present a detailed, physics-based approach for modelling particulate matter (PM10) and tropospheric ozone (O3) removal by urban greenery on a small scale that eliminates these constraints. Our procedure combines a dense network of low-cost optical and electrochemical air pollution sensors, and a remote sensing method for greenery structure monitoring derived from Unmanned aerial systems (UAS) imagery processed by the Structure from Motion (SfM) algorithm. This approach enabled the quantification of species- and individual-specific air pollution removal rates by woody plants throughout the growing season, exploring the high spatial and temporal variability of modelled removal rates within an urban forest. The total PM10 and O3 removal rates ranged from 7.6 g m-2 (PM10) and 12.6 g m-2 (O3) for mature trees of Acer pseudoplatanus to 0.1 g m-2 and 0.1 g m-2 for newly planted tree saplings of Salix daphnoides. The present study demonstrates that UAS-SfM can detect differences in structures among and within canopies and by involving these characteristics, they can shift the modelling of air pollution removal towards a level of individual woody plants and beyond, enabling more realistic and accurate quantification of air pollution removal. Moreover, this approach can be similarly applied when modelling other ecosystem services provided by urban greenery.
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•Canopy structure controls air pollution removal by woody plants.•UAS-SfM recognizes small structural differences between and within urban canopies.•High spatial heterogeneity in removal rates within a forest stand could be modelled.•UAS-SfM shifts modelling of air pollution removal to species and individual level.
•Canopy openness (CO) is usually calculated from the whole hemispherical photograph•Ecological relevance of CO at narrower angles of view (AOV) was evaluated•CO at AOV 100° is robust predictor of ...plant assemblage and understorey microclimate•Narrower AOV broadens the spectrum of lenses suitable for canopy photography
Canopy openness determines forest biodiversity, radiation regime and understorey microclimate. Traditionally, canopy openness was calculated from hemispherical photographs with a full 180° angle of view, but photographic equipment providing only narrower angles of view is increasingly used. Despite that, it is unknown how well canopy openness estimated from restricted angles of view predicts different forest characteristics. To fill this gap, we explored how different canopy openness estimates predicts vascular plant species richness and composition, in-situ measured air and soil temperature and photosynthetically active radiation across different types of European deciduous broadleaved forests. We further benchmarked performance of canopy openness against radiation site factors and evaluated accuracy of canopy openness calculation using artifitial calibration targets.
Canopy openness calculated from angles of view < 180° was a better predictor of all measured variables than canopy openness from the whole hemispherical photograph. Openness from 80° - 120° angle of view best explained plant species richness, community composition, in-situ measured air and soil temperatures, and the photosynthetically active radiation. Moreover, canopy openness from a 100° angle of view predicted all variables except maximum air temperature better than the total radiation site factor. Finally, canopy openness calculated from angles of view < 120° was less affected by image quality and therefore more comparable between different photographic equipment including smartphones with an external fisheye lens.
We found that canopy openness from a complete hemisphere is not required for many ecological applications. Therefore, many consumer-grade cameras and smartphones with an external fisheye lens can provide ecologically relevant canopy openness. Nevertheless, specialized cameras and fisheye lenses should still be preferred. Finally, researchers can predict plant assemblages, forest microclimate and understorey radiation regimes better if they calculate canopy openness from ∼100° angle of view rather than from the whole hemispherical photograph.
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Although gully erosion represents an important process of land degradation, only a few studies in the Czechia have quantified the gully erosion rate yet. Because of the complex and nonlinear ...dynamics, the estimation of the gully erosion rate requires a long term and technically difficult research. However, a recent methodological approach in dendrogeomorphology allows to reconstruct a gully development and assess gully erosion rate. Based on geodetic survey, a detailed mapping of four gullies in the Polomené Mountains was carried out. Subsequently, the gully erosion rate was evaluated by the analysis of 73 exposed roots of broadleaved trees. The first erosion episode was detected in 1981, however, most of the roots were exposed in the last 15 years. Gullies have been forming non-continuously showing median erosion rates between 10.0 to 13.4 mm/year. Even though topographic parameters and land use changes in drainage basin area may affect the intensity of erosion, most of the erosion episodes have been probably triggered by extreme rainfall events. This study exemplifies that intesive gully erosion may occur even on forest soils. Vegetation cover influences a morphology of gully slopes, but its ability to prevent intensive gully erosion is limited. Keywords: gully, erosion rate, exposed roots,...
The speed of writing of state-of-the-art ferromagnetic memories is physically limited by an intrinsic gigahertz threshold. Recently, realization of memory devices based on antiferromagnets, in which ...spin directions periodically alternate from one atomic lattice site to the next has moved research in an alternative direction. We experimentally demonstrate at room temperature that the speed of reversible electrical writing in a memory device can be scaled up to terahertz using an antiferromagnet. A current-induced spin-torque mechanism is responsible for the switching in our memory devices throughout the 12-order-of-magnitude range of writing speeds from hertz to terahertz. Our work opens the path toward the development of memory-logic technology reaching the elusive terahertz band.
The interest in understanding scaling limits of magnetic textures such as domain walls spans the entire field of magnetism from its physical fundamentals to applications in information technologies. ...Here, we explore antiferromagnetic CuMnAs in which imaging by x-ray photoemission reveals the presence of magnetic textures down to nanoscale, reaching the detection limit of this established microscopy in antiferromagnets. We achieve atomic resolution by using differential phase-contrast imaging within aberration-corrected scanning transmission electron microscopy. We identify abrupt domain walls in the antiferromagnetic film corresponding to the Néel order reversal between two neighboring atomic planes. Our work stimulates research of magnetic textures at the ultimate atomic scale and sheds light on electrical and ultrafast optical antiferromagnetic devices with magnetic field-insensitive neuromorphic functionalities.
Allan-Herndon-Dudley syndrome (AHDS) is a severe psychomotor disability disorder that also manifests characteristic abnormal thyroid hormone (TH) levels. AHDS is caused by inactivating mutations in ...monocarboxylate transporter 8 (MCT8), a specific TH plasma membrane transporter widely expressed in the central nervous system (CNS).
mutations cause impaired transport of TH across brain barriers, leading to insufficient neural TH supply. There is currently no successful therapy for the neurological symptoms. Earlier work has shown that intravenous (IV), but not intracerebroventricular adeno-associated virus serotype 9 (AAV9) -based gene therapy given to newborn
knockout (
) male mice increased triiodothyronine (T
) brain content and partially rescued TH-dependent gene expression, suggesting a promising approach to treat this neurological disorder.
The potential of IV delivery of AAV9 carrying human MCT8 was tested in the well-established Mct8
/Organic anion-transporting polypeptide 1c1
double knockout (dKO) mouse model of AHDS, which, unlike
mice, displays both neurological and TH phenotype. Further, as the condition is usually diagnosed during childhood, treatment was given intravenously to P30 mice and psychomotor tests were carried out blindly at P120-P140 after which tissues were collected and analyzed.
Systemic IV delivery of AAV9-MCT8 at a juvenile stage led to improved locomotor and cognitive functions at P120-P140, which was accompanied by a near normalization of T
content and an increased response of positively regulated TH-dependent gene expression in different brain regions examined (thalamus, hippocampus, and parietal cortex). The effects on serum TH concentrations and peripheral tissues were less pronounced, showing only improvement in the serum T
/reverse T
(rT
) ratio and in liver
expression.
IV administration of AAV9, carrying the human MCT8, to juvenile dKO mice manifesting AHDS has long-term beneficial effects, predominantly on the CNS. This preclinical study indicates that this gene therapy has the potential to ameliorate the devastating neurological symptoms in patients with AHDS.
We systematically study the anisotropic magnetoresistance (AMR) on a series of optimized (Ga,Mn)As samples. The crystalline and non-crystalline contributions to the AMR were separated and an apparent ...higher-order term (of six-fold symmetry) was identified to be an artefact resulting from the presence of magnetic anisotropy of the material and of the residual fields of external superconducting magnets. In the broad range of nominal Mn concentrations from 2% to 11%, we find the non-crystalline contribution to dominate, although the crystalline terms become relatively more important for higher doping levels. We compare the AMR magnitude with the Boltzmann transport calculations based on the k·p mean-field kinetic-exchange model.
Antiferromagnetic spintronics allows us to explore storing and processing information in magnetic crystals with vanishing magnetization. In this manuscript, we investigate magnetoresistance effects ...in antiferromagnetic CuMnAs upon switching into high-resistive states using electrical pulses. By employing magnetic field sweeps up to 14 T and magnetic field pulses up to \(\sim\) 60 T, we reveal hysteretic phenomena and changes in the magnetoresistance, as well as the resilience of the switching signal in CuMnAs to the high magnetic field. These properties of the switched state are discussed in the context of recent studies of antiferromagnetic textures in CuMnAs.
Sporadic amyotrophic lateral sclerosis (ALS) is a fatal disease with unknown etiology, characterized by a progressive loss of motor neurons leading to paralysis and death typically within 3-5 years ...of onset. Recently, there has been remarkable progress in understanding inherited forms of ALS in which well defined mutations are known to cause the disease. Rodent models in which the superoxide dismutase-1 (SOD1) mutation is overexpressed recapitulate hallmark signs of ALS in patients. Early anatomical changes in mouse models of fALS are seen in the neuromuscular junctions (NMJs) and lower motor neurons, and selective reduction of toxic mutant SOD1 in the spinal cord and muscle of these models has beneficial effects. Therefore, much of ALS research has focused on spinal motor neuron and NMJ aspects of the disease. Here we show that, in the SOD1(G93A) rat model of ALS, spinal motor neuron loss occurs presymptomatically and before degeneration of ventral root axons and denervation of NMJs. Although overt cell death of corticospinal motor neurons does not occur until disease endpoint, we wanted to establish whether the upper motor neuron might still play a critical role in disease progression. Surprisingly, the knockdown of mutant SOD1 in only the motor cortex of presymptomatic SOD1(G93A) rats through targeted delivery of AAV9-SOD1-shRNA resulted in a significant delay of disease onset, expansion of lifespan, enhanced survival of spinal motor neurons, and maintenance of NMJs. This datum suggests an early dysfunction and thus an important role of the upper motor neuron in this animal model of ALS and perhaps patients with the disease.
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