628 research outputs found
Global mapping of river sediment bars
Recently, deep learning has been increasingly applied to global mapping of land‐use and land‐cover classes. However, very few studies have addressed the problem of separating lakes from rivers, and to our knowledge, none have addressed the issue of mapping fluvial sediment bars. We present the first global scale inventory of fluvial gravel bars. Our workflow is based on a state‐of‐the‐art fully convolutional neural network which is applied to Sentinel‐2 imagery at a resolution of 10 m. We use Google Earth Engine to access these data for a study site that covers 89% of the Earth's surface. We count 8.9 million gravel bars with an estimated area of 41 000 km2. Crucially, the workflow we present can be executed within a month of highly automated processing and thus allows for global scale, monthly, monitoring of gravel bars and associated rivers
Interstitial Lung Disease in Rheumatoid Arthritis in the Era of Biologics
Interstitial lung disease (ILD) represents a severe manifestation in connective tissue diseases (CTD), with an overall incidence of 15%, and it is still a challenge for clinicians evaluation and management. ILD is the most common manifestation of lung involvement in Rheumatoid Arthritis (RA), observed in up to 80% of biopsies, 50% of chest Computed Tomography (CT) and only 5% of chest radiographs. Histopatological patterns of ILD in RA may present with different patterns, such as: usual interstitial pneumonia, non specific interstitial pneumonia, desquamative interstitial pneumonia, organizing pneumonia, and eosinophilic infiltration. The incidence of ILD in RA patients is not only related to the disease itself, many drugs may be in fact associated with the development of pulmonary damage. Some reports suggest a causative role for TNFα inhibitors in RA-ILD development/worsening, anyway, no definitive statement can be drawn thus data are incomplete and affected by several variables. A tight control (pulmonary function tests and/or HRCT) is mandatory in patients with preexisting ILD, but it should be also performed in those presenting risk factors for ILD and mild respiratory symptoms. Biologic therapy should be interrupted, and, after excluding triggering infections, corticosteroids should be administered
The COVID-19 Wellbeing Study: Examining perceived coercion and psychological wellbeing during the COVID-19 pandemic by means of an online survey, asynchronous virtual focus groups and individual interviews – a protocol
Introduction: The COVID-19 pandemic has resulted in
many countries applying restrictive measures, such as
lockdown, to contain and prevent further spread. The
psychological impact of lockdown and working as a
healthcare worker on the frontline has been chronicled
in studies pertaining to previous infectious disease
pandemics that have reported the presence of depressive
symptoms, anxiety, insomnia, and post-traumatic stress
symptoms. Potentially linked to psychological well-being
and not yet studied is the possibility that lockdown and
working on the frontline of the pandemic are associated
with perceptions of coercion.
Methods and analysis: The present study aimed
to examine perceived coercion in those who have
experienced COVID-19-related lockdown and/or worked
as a frontline healthcare worker across three European
countries. It aimed to describe how such perceptions may
impact on psychological well-being, coping and posttraumatic growth. It will employ an explanatory mixedmethods research methodology consisting of an online
survey and online asynchronous virtual focus groups
(AVFGs) and individual interviews. χ2
tests and analyses
of variance will be used to examine whether participants
from different countries differ according to demographic
factors, whether there are differences between cohorts on
perceived coercion, depression, anxiety and post-traumatic
growth scores. The relationship between coercion and
symptoms of distress will be assessed using multiple
regression. Both the AVFGs and the narrative interviews
will be analysed using thematic narrative analysis.
Ethics and dissemination: The study has been approved
by University College London’s Research Ethics Committee
under Project ID Number 7335/004. Results will be
disseminated by means of peer-reviewed publications and
at national and/or international conferences
Espécies de patógenos invasores potenciais para plantios de pínus e eucalipto no Brasil
Sessão de Painéis
Review Article Interstitial Lung Disease in Rheumatoid Arthritis in the Era of Biologics
Interstitial lung disease (ILD) represents a severe manifestation in connective tissue diseases (CTD), with an overall incidence of 15%, and it is still a challenge for clinicians evaluation and management. ILD is the most common manifestation of lung involvement in Rheumatoid Arthritis (RA), observed in up to 80% of biopsies, 50% of chest Computed Tomography (CT) and only 5% of chest radiographs. Histopatological patterns of ILD in RA may present with different patterns, such as: usual interstitial pneumonia, non specific interstitial pneumonia, desquamative interstitial pneumonia, organizing pneumonia, and eosinophilic infiltration. The incidence of ILD in RA patients is not only related to the disease itself, many drugs may be in fact associated with the development of pulmonary damage. Some reports suggest a causative role for TNFα inhibitors in RA-ILD development/worsening, anyway, no definitive statement can be drawn thus data are incomplete and affected by several variables. A tight control (pulmonary function tests and/or HRCT) is mandatory in patients with preexisting ILD, but it should be also performed in those presenting risk factors for ILD and mild respiratory symptoms. Biologic therapy should be interrupted, and, after excluding triggering infections, corticosteroids should be administered
Control of position and movement is simplified by combined muscle spindle and Golgi tendon organ feedback
Whereas muscle spindles play a prominent role in current theories of human motor control, Golgi tendon organs (GTO) and their associated tendons are often neglected. This is surprising since there is ample evidence that both tendons and GTOs contribute importantly to neuromusculoskeletal dynamics. Using detailed musculoskeletal models, we provide evidence that simple feedback using muscle spindles alone results in very poor control of joint position and movement since muscle spindles cannot sense changes in tendon length that occur with changes in muscle force. We propose that a combination of spindle and GTO afferents can provide an estimate of muscle-tendon complex length, which can be effectively used for low-level feedback during both postural and movement tasks. The feasibility of the proposed scheme was tested using detailed musculoskeletal models of the human arm. Responses to transient and static perturbations were simulated using a 1-degree-of-freedom (DOF) model of the arm and showed that the combined feedback enabled the system to respond faster, reach steady state faster, and achieve smaller static position errors. Finally, we incorporated the proposed scheme in an optimally controlled 2-DOF model of the arm for fast point-to-point shoulder and elbow movements. Simulations showed that the proposed feedback could be easily incorporated in the optimal control framework without complicating the computation of the optimal control solution, yet greatly enhancing the system's response to perturbations. The theoretical analyses in this study might furthermore provide insight about the strong physiological couplings found between muscle spindle and GTO afferents in the human nervous system. © 2013 the American Physiological Society
Nonlinear Model Reduction and Decentralized Control of Tethered Formation Flight by Oscillation Synchronization
This paper describes a fully decentralized nonlinear control law for spinning tethered formation flight, based on exploiting geometric symmetries to reduce the original nonlinear dynamics into simpler stable dynamics. Motivated by oscillation synchronization in biological systems, we use contraction theory to prove that a control law stabilizing a single-tethered spacecraft can also stabilize arbitrary large circular arrays of spacecraft, as well as the three inline configuration. The convergence result is global and exponential. Numerical simulations and experimental results using the SPHERES testbed validate the
exponential stability of the tethered formation arrays by implementing a tracking control law derived from the reduced dynamics
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