13 research outputs found

    Embedding Adaptive Features in the ArduPilot Control Architecture for Unmanned Aerial Vehicles

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    The operation of Unmanned Aerial Vehicles (UAVs) is often subject to state-dependent alterations and unstructured uncertainty factors, such as unmodelled dynamics, environmental weather disturbances, aerodynamics gradients, or changes in inertia and mass due to payloads. While a large number of autopilot solutions have been proposed to operate UAVs, none of these solutions is able to counteract the effects of state-dependent and unstructured uncertainties online by parameter estimation and adaptive control techniques. This work presents a systematic integration of adaptive control into ArduPilot, a popular open-source autopilot suite maintained by a large community of UAV developers. Adaptation features are embedded in the ArduPilot control structure without altering the original architecture, to allow users to use the autopilot suite as usual. Tests show that the proposed adaptive ArduPilot provides consistent improved performance in several uncertain flight conditions. The source code of the proposed adaptive ArduPilot is released at https://github.com/Friend-Peng/Adaptive-ArduPilot-Autopilot.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Team Bart De Schutte

    Temporal and instantaneous connectivity of default mode network estimated using Gaussian Bayesian network frameworks

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    By probing its functional anatomy, the default mode network (DMN) can be considered consisting of two interacting hub and non-hub subsystems. The hub subsystem includes posterior cingulate cortex (PCC), medial prefrontal cortex (MPFC) and bilateral inferior parietal cortex (IPC). The non-hub subsystem contains inferior temporal cortex (ITC) and (para) hippocampus (HC). In this study, Gaussian Bayesian Network (BN) and Gaussian Dynamic Bayesian Network (DBN) were applied separately to detect the instantaneous and temporal connection relationship within each and between the two DMN subsystems. It was found that the directional instantaneous interactions between the two subsystems were primarily "from non-hub to hub". The temporal interactions between hub and non-hub regions, on the other hand, are less presented between the two subsystems. The hub subsystem demonstrated both strong instantaneous and temporal interactions among the hub regions, while the non-hub regions were only strongly inter-connected instantaneously but temporally isolated with each other. In addition, one of the hub regions, PCC, appears to be a confluent node and important in the functional integration within the network. (c) 2012 Elsevier Ireland Ltd. All rights reserved

    Expression Changes in the Stroma of Prostate Cancer Predict Subsequent Relapse

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    Biomarkers are needed to address overtreatment that occurs for the majority of prostate cancer patients that would not die of the disease but receive radical treatment. A possible barrier to biomarker discovery may be the polyclonal/multifocal nature of prostate tumors as well as cell-type heterogeneity between patient samples. Tumor-adjacent stroma (tumor microenvironment) is less affected by genetic alteration and might therefore yield more consistent biomarkers in response to tumor aggressiveness. To this end we compared Affymetrix gene expression profiles in stroma near tumor and identified a set of 115 probe sets for which the expression levels were significantly correlated with time-to-relapse. We also compared patients that chemically relapsed shortly after prostatectomy (<1 year), and patients that did not relapse in the first four years after prostatectomy. We identified 131 differentially expressed microarray probe sets between these two categories. 19 probe sets (15 genes overlapped between the two gene lists with p<0.0001). We developed a PAM-based classifier by training on samples containing stroma near tumor: 9 rapid relapse patient samples and 9 indolent patient samples. We then tested the classifier on 47 different samples, containing 90% or more stroma. The classifier predicted the risk status of patients with an average accuracy of 87%. This is the first general tumor microenvironment-based prognostic classifier. These results indicate that the prostate cancer microenvironment exhibits reproducible changes useful for predicting outcomes for patients.Biomarkers are needed to address overtreatment that occurs for the majority of prostate cancer patients that would not die of the disease but receive radical treatment. A possible barrier to biomarker discovery may be the polyclonal/multifocal nature of prostate tumors as well as cell-type heterogeneity between patient samples. Tumor-adjacent stroma (tumor microenvironment) is less affected by genetic alteration and might therefore yield more consistent biomarkers in response to tumor aggressiveness. To this end we compared Affymetrix gene expression profiles in stroma near tumor and identified a set of 115 probe sets for which the expression levels were significantly correlated with time-to-relapse. We also compared patients that chemically relapsed shortly after prostatectomy (<1 year), and patients that did not relapse in the first four years after prostatectomy. We identified 131 differentially expressed microarray probe sets between these two categories. 19 probe sets (15 genes overlapped between the two gene lists with p<0.0001). We developed a PAM-based classifier by training on samples containing stroma near tumor: 9 rapid relapse patient samples and 9 indolent patient samples. We then tested the classifier on 47 different samples, containing 90% or more stroma. The classifier predicted the risk status of patients with an average accuracy of 87%. This is the first general tumor microenvironment-based prognostic classifier. These results indicate that the prostate cancer microenvironment exhibits reproducible changes useful for predicting outcomes for patients

    Protective effects of C-phycocyanin on alcohol-induced subacute liver injury in mice

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    Excessive and long-term alcohol consumption leads to liver disease and low immunity. Extensive evidence suggests that C-phycocyanin (C-PC), a chromophore phycocyanobilin derived from Arthrospira (Spirulina) platensis, exerts protective effects against chemical-induced organ damage and improves immunity. In this study, we investigated whether C-PC could protect against ethanol-induced subacute liver injury and improve immunity. KM mice with ethanol-induced liver injury were established, and animals were divided into three groups that were treated with high, medium, and low doses of C-PC. Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglyceride (TG), total cholesterol (CHOL), low-density lipoprotein (LDL), total bilirubin (TBIL), liver homogenate malondialdehyde (MDA), and superoxide dismutase (SOD) levels were measured. In addition, the number of thymus T cell subsets was assessed, and liver sections were examined pathologically. C-PC exhibited obvious inhibitory effects on serum ALT, AST, TG, CHOL, LDL, and MDA levels and increased SOD content significantly in the liver. C-PC also increased serum CD3+ and CD4+ cell activation and T cell proliferation significantly compared with the model group. The structure of the hepatic lobules was clear, the liver sinus returned to normal, and the liver cell cords were arranged in neat rows. Therefore, C-PC could protect against ethanol-induced subacute liver injury significantly

    Synthesized Attributes of Water Use by Regional Vegetation: A Key to Cognition of "Water Pump" Viewpoint

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    Recently, the frequent seasonal drought in Southwest China has brought considerable concerns and continuous heated arguments on the "water pump" viewpoint (i.e., the water demand from Hevea spp. and Eucalyptus spp. can be treated as a water pump) once again. However, such viewpoint just focused on water consumption from vegetation transpiration and its ecoenvironment impacts, which had not considered other attributes of vegetation, namely, water saving and drought resistance, and hydrological regulation (water conservation) into consideration. Thus, in this paper, the synthesized attributes of regional vegetation water use had been mainly discussed. The results showed that the study on such aspects as the characters of water consumption from vegetation transpiration, the potential of water saving and drought resistance, and the effects of hydrological regulation in Southwest China lagged far behind, let alone the report on synthesized attributes of water utilization with the organic combination of the three aspects above or the paralleled analysis. Accordingly, in this paper, the study on the synthesized attributes of water use by regional vegetation in Southwest China was suggested, and the objectives of such a special study were clarified, targeting the following aspects: (i) characters of water consumption from transpiration of regional typical artificial vegetation; (ii) potential of water saving and drought resistance of regional typical artificial vegetation; (iii) effects of hydrological regulation of regional typical artificial vegetation; (iv) synthesized attributes of water use by regional typical artificial vegetation. It is expected to provide a new idea for the scientific assessment on the regional vegetation ecoenvironment effects and theoretical guidance for the regional vegetation reconstruction and ecological restoration.Recently, the frequent seasonal drought in Southwest China has brought considerable concerns and continuous heated arguments on the "water pump" viewpoint (i.e., the water demand from Hevea spp. and Eucalyptus spp. can be treated as a water pump) once again. However, such viewpoint just focused on water consumption from vegetation transpiration and its ecoenvironment impacts, which had not considered other attributes of vegetation, namely, water saving and drought resistance, and hydrological regulation (water conservation) into consideration. Thus, in this paper, the synthesized attributes of regional vegetation water use had been mainly discussed. The results showed that the study on such aspects as the characters of water consumption from vegetation transpiration, the potential of water saving and drought resistance, and the effects of hydrological regulation in Southwest China lagged far behind, let alone the report on synthesized attributes of water utilization with the organic combination of the three aspects above or the paralleled analysis. Accordingly, in this paper, the study on the synthesized attributes of water use by regional vegetation in Southwest China was suggested, and the objectives of such a special study were clarified, targeting the following aspects: (i) characters of water consumption from transpiration of regional typical artificial vegetation; (ii) potential of water saving and drought resistance of regional typical artificial vegetation; (iii) effects of hydrological regulation of regional typical artificial vegetation; (iv) synthesized attributes of water use by regional typical artificial vegetation. It is expected to provide a new idea for the scientific assessment on the regional vegetation ecoenvironment effects and theoretical guidance for the regional vegetation reconstruction and ecological restoration

    Regional homogeneity of resting-state brain abnormalities in bipolar and unipolar depression

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    Objective: Bipolar disorder patients experiencing a depressive episode (BD-dep) without an observed history of mania are often misdiagnosed and are consequently treated as having unipolar depression CUD), leading to inadequate treatment and poor outcomes. An essential solution to this problem is to identify objective biological markers that distinguish BD-dep and UD patients at an early stage. However, studies directly comparing the brain dysfunctions associated with BD-dep and UD are rare. More importantly, the specificity of the differences in brain activity between these mental disorders has not been examined. With whole-brain regional homogeneity analysis and region-of-interest (ROI) based receiver operating characteristic (ROC) analysis, we aimed to compare the resting-state brain activity of BD-dep and UD patients. Furthermore, we examined the specific differences and whether these differences were attributed to the brain abnormality caused by BD-dep, UD, or both. Methods: Twenty-one bipolar and 21 unipolar depressed patients, as well as 26 healthy subjects matched for gender, age, and educational levels, participated in the study. We compared the differences in the regional homogeneity (ReHo) of the BD-dep and UD groups and further identified their pathophysiological abnormality. In the brain regions showing a difference between the BD-dep and UD groups, we further conducted receptive operation characteristic (ROC) analyses to confirm the effectiveness of the identified difference in classifying the patients. Results: We observed ReHo differences between the BD-dep and UD groups in the right ventrolateral middle frontal gyrus, right dorsal anterior insular, right ventral anterior insular, right cerebellum posterior gyrus, right posterior cingulate cortex, right parahippocampal gyrus, and left cerebellum anterior gyrus. Further ROI comparisons and ROC analysis on these ROIs showed that the right parahippocampal gyrus reflected abnormality specific to the BD-dep group, while the right middle frontal gyrus, the right dorsal anterior insular, the right cerebellum posterior gyrus, and the right posterior cingulate cortex showed abnormality specific to the UD group. Conclusions: We found brain regions showing resting state ReHo differences and examined their sensitivity and specificity, suggesting a potential neuroimaging biomarker to distinguish between BD-dep and UD patients. We further clarified the pathophysiological abnormality of these regions for each of the two patient populations. (C) 2012 Elsevier Inc. All rights reserved

    Spatial-temporal vegetation succession in Yao'an County, Yunnan Province, Southwest China during 1976-2014: A case survey based on RS technology for mountains eco-engineering

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    The remote sense (RS) technology was adopted to explore the vegetation succession from 1976 to 2014 in Yao'an County, Yunnan Province, Southwest China. The results showed: (i) the changes in the distribution range of major vegetation types in the study area. In the 6 statistic years after 1976, in the study area, the distribution range of the secondary vegetation shrank greatly in 4 different subareas (northeast, southeast, northwest and northwest subarea), at 4 different altitudes (1500-1800 m, 1800-2100 m, 2100-2400m and 2400-2700m), on 4 different gradients (0-8 degrees, 8-15 degrees, 15-25 degrees, 25-35 degrees) and on 4 different aspects but the flat land (sunny slope, semi-sunny slope, semi-shadowy slope, and shadowy slope); by contrast, in the study area, the distribution range of artificial vegetation expanded greatly in all the subareas, at 2 different altitudes (1800-2100 m and 2100-2400 m), on 3 different gradients (0-8 degrees, 8-15 degrees, 15-25 degrees), and on the 4 different aspects but the flat land. (ii) The increase and decrease in distribution area of major vegetation types in the study area. During the research period, the total area of major vegetation fluctuated between 1471.92 and 1196.94 km(2), averaging 1255.52 km(2) annually, with the fluctuation rate between -4.67% and 17.24%. In the second statistic year (1989), the total area of major vegetation decreased sharply, and then remained relatively stable afterward. During the research period, the distribution area of the secondary vegetation decreased sharply in the 6 statistic years after 1976, in contrast to the sharp increase in the distribution area of artificial vegetation in such 6 years. During the research period, the total area of major vegetation decreased by 258.73 km(2) in total, among which the total area of the secondary vegetation decreased by 342.52 km(2) in contrast to the increase in artificial vegetation by 83.78 km(2) in total. Thus, it indicated that the secondary vegetation in the study area had been damaged seriously, and the construction of artificial vegetation lagged behind, so there was a potential danger in ecological safety, which should be concerned and precautioned. (C) 2014 Elsevier B.V. All rights reserved.The remote sense (RS) technology was adopted to explore the vegetation succession from 1976 to 2014 in Yao'an County, Yunnan Province, Southwest China. The results showed: (i) the changes in the distribution range of major vegetation types in the study area. In the 6 statistic years after 1976, in the study area, the distribution range of the secondary vegetation shrank greatly in 4 different subareas (northeast, southeast, northwest and northwest subarea), at 4 different altitudes (1500-1800 m, 1800-2100 m, 2100-2400m and 2400-2700m), on 4 different gradients (0-8 degrees, 8-15 degrees, 15-25 degrees, 25-35 degrees) and on 4 different aspects but the flat land (sunny slope, semi-sunny slope, semi-shadowy slope, and shadowy slope); by contrast, in the study area, the distribution range of artificial vegetation expanded greatly in all the subareas, at 2 different altitudes (1800-2100 m and 2100-2400 m), on 3 different gradients (0-8 degrees, 8-15 degrees, 15-25 degrees), and on the 4 different aspects but the flat land. (ii) The increase and decrease in distribution area of major vegetation types in the study area. During the research period, the total area of major vegetation fluctuated between 1471.92 and 1196.94 km(2), averaging 1255.52 km(2) annually, with the fluctuation rate between -4.67% and 17.24%. In the second statistic year (1989), the total area of major vegetation decreased sharply, and then remained relatively stable afterward. During the research period, the distribution area of the secondary vegetation decreased sharply in the 6 statistic years after 1976, in contrast to the sharp increase in the distribution area of artificial vegetation in such 6 years. During the research period, the total area of major vegetation decreased by 258.73 km(2) in total, among which the total area of the secondary vegetation decreased by 342.52 km(2) in contrast to the increase in artificial vegetation by 83.78 km(2) in total. Thus, it indicated that the secondary vegetation in the study area had been damaged seriously, and the construction of artificial vegetation lagged behind, so there was a potential danger in ecological safety, which should be concerned and precautioned. (C) 2014 Elsevier B.V. All rights reserved

    Generation of β€œVirtual” Control Groups for Single Arm Prostate Cancer Adjuvant Trials

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    <div><p>It is difficult to construct a control group for trials of adjuvant therapy (Rx) of prostate cancer after radical prostatectomy (RP) due to ethical issues and patient acceptance. We utilized 8 curve-fitting models to estimate the time to 60%, 65%, … 95% chance of progression free survival (PFS) based on the data derived from Kattan post-RP nomogram. The 8 models were systematically applied to a training set of 153 post-RP cases without adjuvant Rx to develop 8 subsets of cases (reference case sets) whose observed PFS times were most accurately predicted by each model. To prepare a virtual control group for a single-arm adjuvant Rx trial, we first select the optimal model for the trial cases based on the minimum weighted Euclidean distance between the trial case set and the reference case set in terms of clinical features, and then compare the virtual PFS times calculated by the optimum model with the observed PFSs of the trial cases by the logrank test. The method was validated using an independent dataset of 155 post-RP patients without adjuvant Rx. We then applied the method to patients on a Phase II trial of adjuvant chemo-hormonal Rx post RP, which indicated that the adjuvant Rx is highly effective in prolonging PFS after RP in patients at high risk for prostate cancer recurrence. The method can accurately generate control groups for single-arm, post-RP adjuvant Rx trials for prostate cancer, facilitating development of new therapeutic strategies.</p></div

    Emotional reactions to scandals: When does moral character make a difference?

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    A scandal can evoke public outrage when it is widely publicized and involves an individual who is perceived to have a high level of cultural representativeness. Two experiments showed that when the scandalous target's moral character was highlighted, emotional responses towards the target were least negative when the scandal was widely circulated and when the target was seen as a representative of his culture. These results suggest that when a cultural symbol is implicated in a widely-circulated scandal, the negative emotions directed towards the scandalous individual can be alleviated when the public remains confident in his or her commitment to morality
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