165 research outputs found
Neural computations of threat in the aftermath of combat trauma
© 2019, The Author(s), under exclusive licence to Springer Nature America, Inc. By combining computational, morphological, and functional analyses, this study relates latent markers of associative threat learning to overt post-traumatic stress disorder (PTSD) symptoms in combat veterans. Using reversal learning, we found that symptomatic veterans showed greater physiological adjustment to cues that did not predict what they had expected, indicating greater sensitivity to prediction errors for negative outcomes. This exaggerated weighting of prediction errors shapes the dynamic learning rate (associability) and value of threat predictive cues. The degree to which the striatum tracked the associability partially mediated the positive correlation between prediction-error weights and PTSD symptoms, suggesting that both increased prediction-error weights and decreased striatal tracking of associability independently contribute to PTSD symptoms. Furthermore, decreased neural tracking of value in the amygdala, in addition to smaller amygdala volume, independently corresponded to higher PTSD symptom severity. These results provide evidence for distinct neurocomputational contributions to PTSD symptoms
Train model acceleration and deceleration
In order to accelerate a heavy train model with great dimensions to a speed higher than 300 km h(-1) in a moving train model testing system, compressed air is utilized to drive the train model indirectly. The gas from an air gun pushes the piston in an accelerating tube forward. The piston is connected to the trailer through a rope, and the trailer pulls the train model to the desired speed. After the testing section, the train model enters the deceleration section. The speed of the train model gradually decreases because of the braking force of the magnetic braking device on the bottom of the train model and the steel plates fixed on the floor of this device. The dissipation of kinetic energy of the trailer is also based on a similar principle. The feasibility of these methods has been examined in a 180 m-long moving train model testing system. The speed of the trailer alone reaches up to 490 km h(-1). Consequently, a 34.8 kg model accelerates up to 350 km h(-1); the smooth and safe stopping of the model is also possible
Pan-cancer analysis of whole genomes
Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale(1-3). Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter(4); identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation(5,6); analyses timings and patterns of tumour evolution(7); describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity(8,9); and evaluates a range of more-specialized features of cancer genomes(8,10-18).Peer reviewe
Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine
[This corrects the article DOI: 10.1186/s13054-016-1208-6.]
Interactive Evaluation of the Reliability of Engineered Slopes Utilising Multi-source Monitoring Information
Important engineered slopes are often heavily instrumented and their performance routinely monitored through these instruments. The evaluation of the safety of the slopes based on the monitored information is however a challenge. A systematic method is presented in this paper for evaluating the slope safety by combining multi-source monitoring information with underlying physical mechanisms. First, a Bayesian network with continuously distributed variables for a slope involving the factor of safety, multiple monitoring indexes and their influencing soil or rock model parameters is constructed. Then the prior probabilities for the Bayesian network are quantified considering model and parameter uncertainties. After that, multi-source monitoring information is used to update the probability distributions of the soil or rock model parameters and the factor of safety or failure probability using Markov Chain Monte Carlo simulation. Two rock slope examples are worked out to illustrate the proposed methodology. A non-intrusive stochastic numerical method is used in the reliability analysis in the examples
Specification and Implementation of a DMA Controller in an Embedded System
The fast growing of In-Car entertainment application leads to an increasing challenge for both data computation and data communication, which are managed by the microprocessor. The thesis project is the third stage of a continuous Direct Memory Access(DMA) Controller project in NXP Semiconductors for the purpose of specifying and implementing a DMA Controller to take over data communication tasks from the microprocessor. In the first step of the thesis, a test principle was investigated to fully test the existing results, but the simulation results of the Core Unit did not satisfy the requirements. The Core Unit of the DMA Controller is responsible for the sequential-single transfer and burst transfer involving wait states. The existing specification and implementation were analyzed, and a number of possible approaches for improvements were identified. During the second step, the Core Unit was re-specified according to these approaches, and fully implemented using VHDL to fulfill the requirements. After the Core Unit design, the functions of Linked List transfer was specified with Hatley and Pirbhai methodology. The Linked List Unit, which manages the Linked List transfer, was specified to support both the Static and Dynamic Linked List transfer. This specification provides an essential base for the future implementation. The implementation of the Core Unit was tested with Simvision following the proposed test principle. The results satisfied the function requirements. Thus, the specification was proved to be feasible. Additionally, the Core Unit was synthesized using Cadence Ambit. The number of the equivalent gates of a Core Unit Cell is 3k, which is smaller than the currently used DMA Controller in NXP Semiconductors.Microelectronics & Computer EngineeringElectrical Engineering, Mathematics and Computer Scienc
Method for detection of a flaw or flaws in a railway track, and a rail vehicle to be used in such a method
Rail vehicle (1) having rail wheels (3,4) accommodated to guide the rail vehicle along a railway track (2) and said vehicle comprising means for detection of a flaw or flaws in the railway track, wherein the rail vehicle is provided with a noncontact vibrometer (9,10) which is arranged to measure vibrational movement of the railway track surface.Precision and Microsystems EngineeringMechanical, Maritime and Materials Engineerin
Analysis, design and fabrication of tapered integrated optical structures: Implementation of the fully vectorial 3-D beam propagation method
Applied Science
Estimation of train dwell time at short stops based on track occupation event data
Train dwell time is one of the most unpredictable components of railway operations mainly due to the varying volumes of alighting and boarding passengers. For reliable estimations of train running times and route conflicts on main lines it is however necessary to obtain accurate estimations of dwell times at the intermediate stops on the main line, the so-called short stops. This is a big challenge for a more reliable, efficient and robust train operation. Previous research has shown that dwell time is highly dependent on the number of boarding and alighting passengers. However, the latter numbers are usually not available in real time. This paper discusses the possibility of a dwell time estimation model at short stops without passenger demand information, by means of a statistical analysis of track occupation data from the Netherlands. The analysis showed that the dwell times are best estimated for peak and off-peak hour separately. The peak hour dwell times are estimated using a linear regression model of train length, dwell times at previous stops and dwell times of the previous trains. The off-peak hour dwell times are estimated using a non-parametric regression model. There are two major advantages of the proposed estimation model. The model does not need passenger flow data which is usually impossible to know in real time in practice. Also, detailed parameters of rolling stock configuration and platform layout are not required, which eases implementation.Transport & PlanningCivil Engineering and Geoscience
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