Airborne observations of arctic-boreal water surface elevations from AirSWOT Ka-Band InSAR and LVIS LiDAR

AirSWOT is an experimental airborne Ka-band radar interferometer developed by NASA-JPL as a validation instrument for the forthcoming NASA Surface Water and Ocean Topography (SWOT) satellite mission. In 2017, AirSWOT was deployed as part of the NASA Arctic Boreal Vulnerability Experiment (ABoVE) to map surface water elevations across Alaska and western Canada. The result is the most extensive known collection of near-nadir airborne Ka-band interferometric synthetic aperture radar (InSAR) data and derivative high-resolution (3.6 m pixel) digital elevation models to produce water surface elevation (WSE) maps. This research provides a synoptic assessment of the 2017 AirSWOT ABoVE dataset to quantify regional WSE errors relative to coincident in situ field surveys and LiDAR data acquired from the NASA Land, Vegetation, and Ice Sensor (LVIS) airborne platform. Results show that AirSWOT WSE data can penetrate cloud cover and have nearly twice the swath-width of LVIS as flown for ABoVE (3.2 km vs. 1.8 km nominal swath-width). Despite noise and biases, spatially averaged AirSWOT WSEs can be used to estimate sub-seasonal hydrologic variability, as confirmed with field GPS surveys and in situ pressure transducers. This analysis informs AirSWOT ABoVE data users of known sources of measurement error in the WSEs as influenced by radar parameters including incidence angle, magnitude, coherence, and elevation uncertainty. The analysis also provides recommended best practices for extracting information from the dataset by using filters for these four parameters. Improvements to data handing would significantly increase the accuracy and spatial coverage of future AirSWOT WSE data collections, aiding scientific surface water studies, and improving the platform’s capability as an airborne validation instrument for SWOT

GluN2B and GluN2D NMDARs dominate synaptic responses in the adult spinal cord

The composition of the postsynaptic ionotropic receptors that receive presynaptically released transmitter is critical not only for transducing and integrating electrical signals but also for coordinating downstream biochemical signaling pathways. At glutamatergic synapses in the adult CNS an overwhelming body of evidence indicates that the NMDA receptor (NMDAR) component of synaptic responses is dominated by NMDARs containing the GluN2A subunit, while NMDARs containing GluN2B, GluN2C, or GluN2D play minor roles in synaptic transmission. Here, we discovered NMDAR-mediated synaptic responses with characteristics not described elsewhere in the adult CNS. We found that GluN2A-containing receptors contribute little to synaptic NMDAR responses while GluN2B dominates at synapses of lamina I neurons in the adult spinal cord. In addition, we provide evidence for a GluN2D-mediated synaptic NMDAR component in adult lamina I neurons. Strikingly, the charge transfer mediated by GluN2D far exceeds that of GluN2A and is comparable to that of GluN2B. Lamina I forms a disti

Target and distractor processing and the influence of load on the allocation of attention to task-irrelevant threat

This study investigated the characteristics of two distinct mechanisms of attention – stimulus enhancement and stimulus suppression – using an event-related potential (ERP) approach. Across three experiments, participants viewed sparse visual search arrays containing one target and one distractor. The main results of Experiments 1 and 2 revealed that whereas neural signals for stimuli that are not inherently salient could be directly suppressed without prior attentional enhancement, this was not the case for stimuli with motivational relevance (human faces). Experiment 3 showed that as task difficulty increased, so did the need for suppression of distractor stimuli. It also showed the preferential attentional enhancement of angry over neutral distractor faces, but only under conditions of high task difficulty, suggesting that the effects of distractor valence on attention are greatest when there are fewer available resources for distractor processing. The implications of these findings are considered in relation to contemporary theories of attention

Behavioural responses of captive-born greater rheas Rhea americana Linnaeus (Rheiformes, Rheidae) submitted to antipredator training

Human activities have been diminishing greater rhea Rhea americana (Linnaeus, 1758) populations throughout their natural distribution. The reintroductions of captive-born greater rheas have been tried but without success; since the individuals reintroduced were killed by predators. Captive-born animals that have been isolated from predators for many generations can lose their predator recognition abilities. To enhance the survival rates of the reintroduced animals, researchers are now using antipredator training techniques. We studied the response of 15 zoo-borne greater rheas to antipredator training. The animals were divided into three groups: two test groups and one control group. We ran 15 antipredator tests and four control testes with each group. Antipredator tests consisted of pairing a taxidermized predator model or a real predator (domestic dog) with a simulation of a capture procedure. Control tests consisted of presenting the predator model (jaguar) to the birds, after training but not associating it with an aversive event and recording behavioural responses. All tests were video-recorded and analysed a posteriori. Results showed that the trained rheas responded appropriately to the predators, becoming more vigilant and that there was considerable individual differences in response to antipredator training. The results demonstrated that antipredator training is effective and therefore an invaluable tool for reintroduction projects involving greater rheas. Furthermore, the methods employed in this research project should be applicable to other species of flightless birds.<br>As atividades humanas têm diminuído as populações de emas Rhea americana (Linnaeus, 1758) por toda sua área de distribuição. Reintroduções de emas nascidas em cativeiro têm sido tentadas, mas sem sucesso, uma vez que os indivíduos reintroduzidos são mortos por predadores. Animais nascidos em cativeiro que foram isolados de seus predadores por várias gerações podem se tornar incapacitados do seu reconhecimento. Para aumentar as taxas de sobrevivência dos animais reintroduzidos, pesquisadores têm utilizado técnicas de treinamento anti-predação. O objetivo deste trabalho foi a aplicação de treinamento anti-predação em emas nascidas em cativeiro e avaliação de suas respostas comportamentais. Foram treinadas 15 emas adultas. Os animais foram divididos em três grupos: dois grupos-teste e um grupo controle. Foram realizados 15 testes anti-predação e quatro testes-controle com cada grupo. O teste anti-predação consistia em parear um modelo taxidermizado de predador (onça-pintada) ou um predador real (cachorro doméstico) com uma simulação de captura. Os testes-controle consistiram na apresentação do modelo do predador (onça empalhada) às aves, depois do treinamento, mas sem a associação com o estímulo aversivo. As respostas comportamentais foram filmadas e os comportamentos anotados posteriormente. Os resultados mostraram que as emas responderam apropriadamente aos predadores, se tornando mais vigilantes, e que existem diferenças individuais evidentes em resposta ao treinamento anti-predação. Os resultados demonstraram que o treinamento anti-predação pode ser uma ferramenta valiosa para futuros projetos de reintrodução envolvendo emas. Além disso, os métodos empregados nesta pesquisa podem ser aplicados a outras espécies de aves não-voadoras