161 research outputs found
Robust visual odometry using uncertainty models
In dense, urban environments, GPS by itself cannot be relied on to provide accurate positioning information. Signal reception issues (e.g. occlusion, multi-path effects) often prevent the GPS receiver from getting a positional lock, causing holes in the absolute positioning data. In order to keep assisting the driver, other sensors are required to track the vehicle motion during these periods of GPS disturbance. In this paper, we propose a novel method to use a single on-board consumer-grade camera to estimate the relative vehicle motion. The method is based on the tracking of ground plane features, taking into account the uncertainty on their backprojection as well as the uncertainty on the vehicle motion. A Hough-like parameter space vote is employed to extract motion parameters from the uncertainty models. The method is easy to calibrate and designed to be robust to outliers and bad feature quality. Preliminary testing shows good accuracy and reliability, with a positional estimate within 2 metres for a 400 metre elapsed distance. The effects of inaccurate calibration are examined using artificial datasets, suggesting a self-calibrating system may be possible in future work
Lattice-corrected strain-induced vector potentials in graphene
The electronic implications of strain in graphene can be captured at low
energies by means of pseudovector potentials which can give rise to
pseudomagnetic fields. These strain-induced vector potentials arise from the
local perturbation to the electronic hopping amplitudes in a tight-binding
framework. Here we complete the standard description of the strain-induced
vector potential, which accounts only for the hopping perturbation, with the
explicit inclusion of the lattice deformations or, equivalently, the
deformation of the Brillouin zone. These corrections are linear in strain and
are different at each of the strained, inequivalent Dirac points, and hence are
equally necessary to identify the precise magnitude of the vector potential.
This effect can be relevant in scenarios of inhomogeneous strain profiles,
where electronic motion depends on the amount of overlap among the local Fermi
surfaces. In particular, it affects the pseudomagnetic field distribution
induced by inhomogeneous strain configurations, and can lead to new
opportunities in tailoring the optimal strain fields for certain desired
functionalities.Comment: Errata for version
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THE EFFECT OF THERMAL CONDITIONS ON PROCESS DEFECTS IN ELECTRON BEAM DIRECTED ENERGY DEPOSITION
Observing process defects at size scales and with sufficient confidence relevant to qualification
efforts has not yet been achieved in metal AM, so non-destructive testing (NDT) techniques are
used to detect porosity within material deposited. NDT costs can be significant and may not
achieve targeted resolution due to geometry and material limitations. In this work, in-process
monitoring of Electron Beam Directed Energy Deposition (EB-DED) is enhanced to include
three thermal history conditions; inter-pass, melt pool superheat and trailing bead temperatures.
Quality scenarios are applied to simulate various process conditions during EB-DED at three
different thermal conditions within production relevant use cases and resultant process defects
are characterized via high throughput computed tomography. Defects are spatially and
temporally registered to process conditions observed during EB-DED and statistically mapped to
thermal scenarios. Thermal condition has a strong influence on the quantity of observed process
defects, with lower interpass temperature resulting in a larger number of defects.Mechanical Engineerin
Sox17 and ß-catenin co-occupy Wnt-responsive enhancers to govern the endoderm gene regulatory network
© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Mukherjee, S., Chaturvedi, P., Rankin, S. A., Fish, M. B., Wlizla, M., Paraiso, K. D., MacDonald, M., Chen, X., Weirauch, M. T., Blitz, I. L., Cho, K. W. Y., & Zorn, A. M. Sox17 and ß-catenin co-occupy Wnt-responsive enhancers to govern the endoderm gene regulatory network. Elife, 9, (2020): e58029, doi:10.7554/eLife.58029.Lineage specification is governed by gene regulatory networks (GRNs) that integrate the activity of signaling effectors and transcription factors (TFs) on enhancers. Sox17 is a key transcriptional regulator of definitive endoderm development, and yet, its genomic targets remain largely uncharacterized. Here, using genomic approaches and epistasis experiments, we define the Sox17-governed endoderm GRN in Xenopus gastrulae. We show that Sox17 functionally interacts with the canonical Wnt pathway to specify and pattern the endoderm while repressing alternative mesectoderm fates. Sox17 and β-catenin co-occupy hundreds of key enhancers. In some cases, Sox17 and β-catenin synergistically activate transcription apparently independent of Tcfs, whereas on other enhancers, Sox17 represses β-catenin/Tcf-mediated transcription to spatially restrict gene expression domains. Our findings establish Sox17 as a tissue-specific modifier of Wnt responses and point to a novel paradigm where genomic specificity of Wnt/β-catenin transcription is determined through functional interactions between lineage-specific Sox TFs and β-catenin/Tcf transcriptional complexes. Given the ubiquitous nature of Sox TFs and Wnt signaling, this mechanism has important implications across a diverse range of developmental and disease contexts.Eunice Kennedy Shriver National Institute of Child Health and Human Development (HD073179)
Ken WY Cho
Aaron M Zorn
National Institute of Diabetes and Digestive and Kidney Diseases (P30DK078392)
Aaron M Zorn
Eunice Kennedy Shriver National Institute of Child Health and Human Development (P01HD093363)
Aaron M Zor
Short-term psychosocial outcomes of adding a non-contrast abdominal computed tomography (CT) scan to the thoracic CT within lung cancer screening.
OBJECTIVES: To evaluate psychological, social, and financial outcomes amongst individuals undergoing a non-contrast abdominal computed tomography (CT) scan to screen for kidney cancer and other abdominal malignancies alongside the thoracic CT within lung cancer screening. SUBJECTS AND METHODS: The Yorkshire Kidney Screening Trial (YKST) is a feasibility study of adding a non-contrast abdominal CT scan to the thoracic CT within lung cancer screening. A total of 500 participants within the YKST, comprising all who had an abnormal CT scan and a random sample of one-third of those with a normal scan between 14/03/2022 and 24/08/2022 were sent a questionnaire at 3 and 6 months. Outcomes included the Psychological Consequences Questionnaire (PCQ), the short-form of the Spielberger State-Trait Anxiety Inventory, and the EuroQoL five Dimensions five Levels scale (EQ-5D-5L). Data were analysed using regression adjusting for participant age, sex, socioeconomic status, education, baseline quality of life (EQ-5D-5L), and ethnicity. RESULTS: A total of 380 (76%) participants returned questionnaires at 3 months and 328 (66%) at 6 months. There was no difference in any outcomes between participants with a normal scan and those with abnormal scans requiring no further action. Individuals requiring initial further investigations or referral had higher scores on the negative PCQ than those with normal scans at 3 months (standardised mean difference 0.28 sd, 95% confidence interval 0.01-0.54; P = 0.044). The difference was greater in those with anxiety or depression at baseline. No differences were seen at 6 months. CONCLUSION: Screening for kidney cancer and other abdominal malignancies using abdominal CT alongside the thoracic CT within lung cancer screening is unlikely to cause significant lasting psychosocial or financial harm to participants with incidental findings
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Transthoracic Echocardiographic Assessment of the Heart in Pregnancy-a position statement on behalf of the British Society of Echocardiography and the United Kingdom Maternal Cardiology Society.
Pregnancy is a dynamic process associated with profound hormonally mediated haemodynamic changes which result in structural and functional adaptations in the cardiovascular system. An understanding of the myocardial adaptations is important for echocardiographers and clinicians undertaking or interpreting echocardiograms on pregnant and post-partum women. This guideline, on behalf of the British Society of Echocardiography and United Kingdom Maternal Cardiology Society, reviews the expected echocardiographic findings in normal pregnancy and in different cardiac disease states, as well as echocardiographic signs of decompensation. It aims to lay out a structure for echocardiographic scanning and surveillance during and after pregnancy as well as suggesting practical advice on scanning pregnant women
Polarized Secretion of Drosophila EGFR Ligand from Photoreceptor Neurons Is Controlled by ER Localization of the Ligand-Processing Machinery
Trafficking within the endoplasmic reticulum and specialized localization of the intra-membrane protease Rhomboid regulate EGF ligand-dependent signaling in Drosophila photoreceptor axon termini
Postpartum blood pressure self-management following hypertensive pregnancy: protocol of the Physician Optimised Post-partum Hypertension Treatment (POP-HT) trial.
INTRODUCTION: New-onset hypertension affects approximately 10% of pregnancies and is associated with a significant increase in risk of cardiovascular disease in later life, with blood pressure measured 6 weeks postpartum predictive of blood pressure 5-10 years later. A pilot trial has demonstrated that improved blood pressure control, achevied via self-management during the puerperium, was associated with lower blood pressure 3-4 years postpartum. Physician Optimised Post-partum Hypertension Treatment (POP-HT) will formally evaluate whether improved blood pressure control in the puerperium results in lower blood pressure at 6 months post partum, and improvements in cardiovascular and cerebrovascular phenotypes. METHODS AND ANALYSIS: POP-HT is an open-label, parallel arm, randomised controlled trial involving 200 women aged 18 years or over, with a diagnosis of pre-eclampsia or gestational hypertension, and requiring antihypertensive medication at discharge. Women are recruited by open recruitment and direct invitation around time of delivery and randomised 1:1 to, either an intervention comprising physician-optimised self-management of postpartum blood pressure or, usual care. Women in the intervention group upload blood pressure readings to a 'smartphone' app that provides algorithm-driven individualised medication-titration. Medication changes are approved by physicians, who review blood pressure readings remotely. Women in the control arm follow assessment and medication adjustment by their usual healthcare team. The primary outcome is 24-hour average ambulatory diastolic blood pressure at 6-9 months post partum. Secondary outcomes include: additional blood pressure parameters at baseline, week 1 and week 6; multimodal cardiovascular assessments (CMR and echocardiography); parameters derived from multiorgan MRI including brain and kidneys; peripheral macrovascular and microvascular measures; angiogenic profile measures taken from blood samples and levels of endothelial circulating and cellular biomarkers; and objective physical activity monitoring and exercise assessment. An additional 20 women will be recruited after a normotensive pregnancy as a comparator group for endothelial cellular biomarkers. ETHICS AND DISSEMINATION: IRAS PROJECT ID 273353. This trial has received a favourable opinion from the London-Surrey Research Ethics Committee and HRA (REC Reference 19/LO/1901). The investigator will ensure that this trial is conducted in accordance with the principles of the Declaration of Helsinki and follow good clinical practice guidelines. The investigators will be involved in reviewing drafts of the manuscripts, abstracts, press releases and any other publications arising from the study. Authors will acknowledge that the study was funded by the British Heart Foundation Clinical Research Training Fellowship (BHF Grant number FS/19/7/34148). Authorship will be determined in accordance with the ICMJE guidelines and other contributors will be acknowledged. TRIAL REGISTRATION NUMBER: NCT04273854
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