5,115 research outputs found

    Artificial intelligence-based software (AID-FOREST) for tree detection: A new framework for fast and accurate forest inventorying using LiDAR point clouds

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    Forest inventories are essential to accurately estimate different dendrometric and forest stand parameters. However, classical forest inventories are time consuming, slow to conduct, sometimes inaccurate and costly. To address this problem, an efficient alternative approach has been sought and designed that will make this type of field work cheaper, faster, more accurate, and easier to complete. The implementation of this concept has required the development of a specifically designed software called "Artificial Intelligence for Digital Forest (AID-FOREST)", which is able to process point clouds obtained via mobile terrestrial laser scanning (MTLS) and then, to provide an array of multiple useful and accurate dendrometric and forest stand parameters. Singular characteristics of this approach are: No data pre-processing is required either pre-treatment of forest stand; fully automatic process once launched; no limitations by the size of the point cloud file and fast computations.To validate AID-FOREST, results provided by this software were compared against the obtained from in-situ classical forest inventories. To guaranty the soundness and generality of the comparison, different tree spe-cies, plot sizes, and tree densities were measured and analysed. A total of 76 plots (10,887 trees) were selected to conduct both a classic forest inventory reference method and a MTLS (ZEB-HORIZON, Geoslam, ltd.) scanning to obtain point clouds for AID-FOREST processing, known as the MTLS-AIDFOREST method. Thus, we compared the data collected by both methods estimating the average number of trees and diameter at breast height (DBH) for each plot. Moreover, 71 additional individual trees were scanned with MTLS and processed by AID-FOREST and were then felled and divided into logs measuring 1 m in length. This allowed us to accurately measure the DBH, total height, and total volume of the stems.When we compared the results obtained with each methodology, the mean detectability was 97% and ranged from 81.3 to 100%, with a bias (underestimation by MTLS-AIDFOREST method) in the number of trees per plot of 2.8% and a relative root-mean-square error (RMSE) of 9.2%. Species, plot size, and tree density did not significantly affect detectability. However, this parameter was significantly affected by the ecosystem visual complexity index (EVCI). The average DBH per plot was underestimated (but was not significantly different from 0) by the MTLS-AIDFOREST, with the average bias for pooled data being 1.8% with a RMSE of 7.5%. Similarly, there was no statistically significant differences between the two distribution functions of the DBH at the 95.0% confidence level.Regarding the individual tree parameters, MTLS-AIDFOREST underestimated DBH by 0.16 % (RMSE = 5.2 %) and overestimated the stem volume (Vt) by 1.37 % (RMSE = 14.3 %, although the BIAS was not statistically significantly different from 0). However, the MTLS-AIDFOREST method overestimated the total height (Ht) of the trees by a mean 1.33 m (5.1 %; relative RMSE = 11.5 %), because of the different height concepts measured by both methodological approaches. Finally, AID-FOREST required 30 to 66 min per ha-1 to fully automatically process the point cloud data from the *.las file corresponding to a given hectare plot. Thus, applying our MTLS-AIDFOREST methodology to make full forest inventories, required a 57.3 % of the time required to perform classical plot forest inventories (excluding the data postprocessing time in the latter case). A free trial of AID -FOREST can be requested at [email protected]

    Should TiO2 nanostructures doped with Li+ be used as photoanodes for photoelectrochemical water splitting applications?

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    Different TiO2 nanostructures, nanotubes and nanosponges, were obtained by anodization of Ti under stagnant and hydrodynamic conditions. Samples were doped with Li+ before and after annealing at 450 °C during 1 h. The nanostructures were characterized by different microscopy techniques: Field Emission Scanning Electron Microscopy (FE-SEM) and Raman Confocal Laser Microscopy. Additionally, Incident Photon-to-electron Conversion Efficiency (IPCE), photoelectrochemical water splitting and stability measurements were also performed. According to the results, TiO2 nanostructures doped before annealing present the worst photocurrent response, even if compared with undoped samples. On the other hand, this study reveals that Li+-doped TiO2 nanostructures doped after annealing can be used as durable and stable photoanodes for photoelectrochemical water splitting applications

    Analysis of the impact of pronation maneuver in patients on mechanical ventilation with diagnosis of pneumonia by Covid-19 and acute respiratory distress syndrome: Análise do impacto da manobra de pronação em pacientes em ventilação mecânica com diagnóstico de pneumonia por Covid-19 e síndrome do desconforto respiratório agudo

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    Objective: To analyze the profile of patients on invasive mechanical ventilation with SARS-CoV-2 pneumonia who were pronated and who developed acute respiratory distress syndrome. Methods: Historical cohort study through the analysis of a database containing 282 patients hospitalized in a large university hospital in the city of Porto Alegre, Brazil. The population studied included individuals infected with SARS-CoV-2 and with a clinical course marked by severe pneumonia and, mainly, by acute respiratory distress syndrome, submitted to mechanical ventilation and invasive pronation maneuver. Results: Database analysis showed a high mortality rate for all patient groups and a high case fatality rate, especially in elderly patients and in individuals with active oncologic disease or with chronic kidney disease. Conclusions: The high overall mortality rate, as well as the high lethality, especially in elderly patients and in individuals with active oncologic disease or with chronic kidney disease, suggests that, for certain specific population groups, the prone maneuver is not effective in reducing high. mortality caused by acute respiratory distress syndrome associated with COVID-19

    Chronic low back pain and its differential diagnoses: a case report

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    Low back pain is a common problem which accompanies a large part of the population. It is estimated that up to 84% of adults will have low back pain at some point in their lives. Rarely, low back pain may be the first manifestation of a serious illness. This case report presents the clinical history of a 79 year-old male, with multiple comorbities, including a report of a discal hernia treated by surgery approximately 30 years before presentation, with residual low back pain since then. The pain was progressively worsening, associated with loss of muscle strength and paresthesia in the right lower limb, with significant weight loss. During screening, significant anemia and acute kidney injury with associated hypercalcemia were observed. A spine CT scan revealed a large expansile lesion obliterating the medullary canal at T8/T9 segment. A monoclonal spike in protein electrophoresis was found, along with sparse lytic lesions in long bones leading to the diagnosis of multiple myeloma. Therefore, this report highlights the importance of considering different differential diagnoses as a cause of low back pain. The correct determination of the etiology is essential for adequate clinical management and improvement of the patient's quality of life

    Coxiella endosymbiont of Rhipicephalus microplus modulates tick physiology with a major impact in blood feeding capacity

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    In the past decade, metagenomics studies exploring tick microbiota have revealed widespread interactions between bacteria and arthropods, including symbiotic interactions. Functional studies showed that obligate endosymbionts contribute to tick biology, affecting reproductive fitness and molting. Understanding the molecular basis of the interaction between ticks and their mutualist endosymbionts may help to develop control methods based on microbiome manipulation. Previously, we showed that Rhipicephalus microplus larvae with reduced levels of Coxiella endosymbiont of R. microplus (CERM) were arrested at the metanymph life stage (partially engorged nymph) and did not molt into adults. In this study, we performed a transcriptomic differential analysis of the R. microplus metanymph in the presence and absence of its mutualist endosymbiont. The lack of CERM resulted in an altered expression profile of transcripts from several functional categories. Gene products such as DA-P36, protease inhibitors, metalloproteases, and evasins, which are involved in blood feeding capacity, were underexpressed in CERM-free metanymphs. Disregulation in genes related to extracellular matrix remodeling was also observed in the absence of the symbiont. Taken together, the observed alterations in gene expression may explain the blockage of development at the metanymph stage and reveal a novel physiological aspect of the symbiont-tick-vertebrate host interaction

    Molecular gas in the Andromeda galaxy

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    We present a new 12CO(J=1-0)-line survey of the Andromeda galaxy, M31, covering the bright disk with the highest resolution to date (85 pc along the major axis), observed On-the-Fly (in italics) with the IRAM 30-m telescope. We discuss the distribution of the CO emission and compare it with the distributions of HI and emission from cold dust traced at 175mum. Our main results are: 1. Most of the CO emission comes from the radial range R=3-16 kpc, but peaks near R=10 kpc. The emission is con- centrated in narrow, arm-like filaments defining two spiral arms with pitch angles of 7d-8d. The average arm-interarm brightness ratio along the western arms reaches 20 compared to 4 for HI. 2. For a constant conversion factor Xco, the molecular fraction of the neutral gas is enhanced in the arms and decreases radially. The apparent gas-to-dust ratios N(HI)/I175 and (N(HI)+2N(H2))/I175 increase by a factor of 20 between the centre and R=14 kpc, whereas the ratio 2N(H2)/I175 only increases by a factor of 4. Implications of these gradients are discussed. In the range R=8-14 kpc total gas and cold dust are well correlated; molecular gas is better correlated with cold dust than atomic gas.Comment: 21 pages, 16 figures. Accepted for publication in A&
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