Work-Based Education as a Pathway to Resilience

The purpose of this study was to explore the potential of work-based education (WBE) as a pathway for enhancing resilience among youth-at-risk for disengaging from school. For students who have experienced traditional academic school as an adverse context, the decision to pursue an alternative path to high school completion, for example WBE, can be interpreted as agentic. We propose that WBE may have the requisite features of an educational context that fosters resilience in at-risk youth. We used a multipleperspective case study method involving three young people in their final stages of secondary school. The students were the focal participants in each case. Each was interviewed and observed on multiple occasions. We interviewed teachers and workplace supervisors associated with each student for additional perspectives. Cases were analyzed individually, followed by cross-case analyses utilizing a resilience framework. Our study revealed evidence that for the three youth we studied, WBE had many elements that appear to enhance resilience in a way that academic programs did not. WBE kept these students engaged in the school context and contributed to the eventual successful completion of secondary school for all three. Choosing WBE as a pathway to secondary school completion can be an agentic act by at-risk youth to achieve graduation. Engagement in WBE also appears to enhance resilience. WBE may foster resilience in at-risk youth, who despite academic adversity, progress to completion. Graduation from secondary school is frequently identified as a positive outcome and a predictor of success in productive occupation and adult life

Guiding-center dynamics of vortex dipoles in Bose-Einstein condensates

A quantized vortex dipole is the simplest vortex molecule, comprising two counter-circulating vortex lines in a superfluid. Although vortex dipoles are endemic in two-dimensional superfluids, the precise details of their dynamics have remained largely unexplored. We present here several striking observations of vortex dipoles in dilute-gas Bose-Einstein condensates, and develop a vortex-particle model that generates vortex line trajectories that are in good agreement with the experimental data. Interestingly, these diverse trajectories exhibit essentially identical quasi-periodic behavior, in which the vortex lines undergo stable epicyclic orbits.Comment: 4 pages, 2 figure

Stabilized vortex solitons in layered Kerr media

In this letter we demonstrate the possibility of stabilizing beams with angular momentum propagating in Kerr media. Large propagation distances without filamentation can be achieved in layered media with alternating focusing and defocusing nonlinearities. Stronger stabilization can be obtained with the addition of an incoherent beam.Comment: 4 pages, 3 figures. We have removed the sentence "Thus, they erroneously point out to the existence of fully stabilized vortex solitons" in page 2, column 2, line 7-8, because it might be confusin

Prediction of final infarct volume from native CT perfusion and treatment parameters using deep learning

CT Perfusion (CTP) imaging has gained importance in the diagnosis of acute stroke. Conventional perfusion analysis performs a deconvolution of the measurements and thresholds the perfusion parameters to determine the tissue status. We pursue a data-driven and deconvolution-free approach, where a deep neural network learns to predict the final infarct volume directly from the native CTP images and metadata such as the time parameters and treatment. This would allow clinicians to simulate various treatments and gain insight into predicted tissue status over time. We demonstrate on a multicenter dataset that our approach is able to predict the final infarct and effectively uses the metadata. An ablation study shows that using the native CTP measurements instead of the deconvolved measurements improves the prediction.Comment: Accepted for publication in Medical Image Analysi

Assessment of Iodine Contrast-To-Noise Ratio in Virtual Monoenergetic Images Reconstructed from Dual-Source Energy-Integrating CT and Photon-Counting CT Data

To evaluate whether the contrast-to-noise ratio (CNR) of an iodinated contrast agent in virtual monoenergetic images (VMI) from the first clinical photon-counting detector (PCD) CT scanner is superior to VMI CNR from a dual-source dual-energy CT scanner with energy-integrating detectors (EID), two anthropomorphic phantoms in three different sizes (thorax and abdomen, QRM GmbH), in combination with a custom-built insert containing cavities filled with water, and water with 15 mg iodine/mL, were scanned on an EID-based scanner (Siemens SOMATOM Force) and on a PCD-based scanner (Siemens, NAEOTOM Alpha). VMI (range 40–100 keV) were reconstructed without an iterative reconstruction (IR) technique and with an IR strength of 60% for the EID technique (ADMIRE) and closest matching IR strengths of 50% and 75% for the PCD technique (QIR). CNR was defined as the difference in mean CT numbers of water, and water with iodine, divided by the root mean square value of the measured noise in water, and water with iodine. A two-sample t-test was performed to evaluate differences in CNR between images. A p-value &lt; 0.05 was considered statistically significant. For VMI without IR and below 60 keV, the CNR of the PCD-based images at 120 and 90 kVp was up to 55% and 75% higher than the CNR of the EID-based images, respectively (p &lt; 0.05). For VMI above 60 keV, CNRs of PCD-based images at both 120 and 90 kVp were up to 20% lower than the CNRs of EID-based images. Similar or improved performance of PCD-based images in comparison with EID-based images were observed for VMIs reconstructed with IR techniques. In conclusion, with PCD-CT, iodine CNR on low energy VMI (&lt;60 keV) is better than with EID-CT.</p

Visualizing the 3D collagen structure of human atherosclerotic plaques using Diffusion Tensor Imaging

Introduction Ischemic strokes and heart attacks are mainly caused by rupture of the fibrous cap of an atherosclerotic plaque. Reliable prediction of the fibrous cap rupture is, therefore, crucial to prevent these potentially lethal cardiovascular events. Since cap rupture occurs when the stresses in the cap exceed the strength of the cap, biomechanical modeling may help to improve cap rupture prediction. Biomechanical models depend strongly on the material parameters used as input. Previous studies focused on the anisotropic mechanical behaviour of atherosclerotic plaques and produced stiffness values for the collagen fibers in plaques [1]. However, for a more complete characterization knowledge of the global 3D collagen architecture in atherosclerotic plaques is required. Therefore, for the first time diffusion tensor imaging (DTI) was used to investigate the 3D collagen structure of human atherosclerotic plaques. Methods Until now five human carotid atherosclerotic plaques were obtained from endarterectomy patients and embedded in 4 % type VII agarose. The samples were placed in a 9.4 T horizontal-bore MRI scanner to conduct DTI. DTI enabled the tracking of the fiber directions and visualisation of the collagen fibers [2]. Results The consistent results of five different plaques suggest that collagen fibers are deposited in a new layer in a different direction during the development of atherosclerosis (see figure for one representative result). Two distinct layers of collagen fibers were found; an outer layer, where the collagen is aligned in the circumferential direction (14.5°±28.0°), similar to healthy arteries [2], and an inner layer where the collagen follows a longitudinal direction (77.4°±22.4°). Conclusions DTI allowed the visualization of the global 3D collagen architecture of atherosclerotic plaques. The inner collagen layer showed a surprising result and implies a change of strain distribution in the artery during the later stage of atherosclerosis, possibly due to the thickening and stiffening of the diseased intimal tissue. These data, combined with collagen stiffness data found in previous studies [1], will be used as input for biomechanical models including the anisotropic mechanical behaviour of plaque tissue. Models using general over-simplified assumptions like isotropic behaviour can be replaced by models including the anisotopic behavior and thereby improve the stress analysis of plaques. Improved models might help in the diagnosis and treatment of plaque rupture preventing heart attacks and ischemic strokes. References [1] Chai C-K, Akyildiz AC, Speelman L, Gijsen FJH, Oomens CWJ, Sambeek MRHM, van der Lugt A, Baaijens FTP, Anisotropic mechanical behaviour of carotid atherosclerotic plaques at large strain, The 8th international symposium on Biomechanics in Vascular Biology and Cardiovascular Disease, Rotterdam, 2013. [2] Ghazanfari S, Driessen-Mol A, Strijkers GJ, Kanters FMW, Baaijens FPT, Bouten CVC, A comparative analysis of the collagen architecture in the carotid artery: Second harmonic generation versus diffusion tensor imaging, Biochemical and Biophysical Research Communications, 426(1): 54-58, 2012

Long-Term Stroke Risk in Patients With New Ischemic Brain Lesions on MRI After Carotid Revascularization

BACKGROUND: Carotid artery revascularization can result in new ischemic brain lesions on diffusion-weighted magnetic resonance imaging. This study aimed to investigate the relationship between periprocedural ischemic diffusion-weighted imaging (DWI) lesions after carotid artery revascularization and recurrent long-term cerebrovascular events. METHODS: A secondary observational prospective cohort analysis of existing clinical trial data was performed on 162 patients with symptomatic carotid stenosis that were previously randomized to carotid artery stenting or carotid endarterectomy in the ICSS (International Carotid Stenting Study) and included in the magnetic resonance imaging substudy. Magnetic resonance imagings were performed 1 to 7 days before and 1 to 3 days after treatment. The primary composite clinical outcome was the time to any stroke or transient ischemic attack during follow-up. Patients with new diffusion-weighted imaging (DWI) lesions on posttreatment magnetic resonance imaging scan (DWI+) were compared with patients without new lesions (DWI-). RESULTS: The median time of follow-up was 8.6 years (interquartile range, 5.0-12.5). Kaplan-Meier cumulative incidence for the primary outcome after 12.5-year follow-up was 35.3% (SE, 8.9%) in DWI+ patients and 31.1% (SE, 5.6%) in DWI- patients. Uni- and multivariable regression analyses did not show significant differences (hazard ratio, 1.50 [95% CI, 0.76-2.94] and hazard ratio, 1.30 [95% CI, 0.10-1.02], respectively). Higher event rate of the primary outcome in DWI+ patients in the overall cohort was mainly caused by events in the carotid artery stenting group. CONCLUSIONS: Based on our outcome analysis within the ICSS magnetic resonance imaging substudy, DWI lesions following carotid revascularization did not seem to have a relationship with long-term stroke risk. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: ISRCTN 25337470.</p

The isolation of Campylobacter hyointestinalis from a pig in South Africa

The isolation of a strain of Campylobacter hyointestinalis from a piglet is described. The animal originated from a farm where another animal showed signs of intestinal adenomatosis. The animal from which the Isolation was made had diarrhoea, and an enteropathogenic Escherichia coli was also isolated. No pathological changes indicative of intestinal adenomatosis were detected in this animal.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.lmchunu2014mn201