Patient-specific CFD simulation of intraventricular haemodynamics based on 3D ultrasound imaging

Background: The goal of this paper is to present a computational fluid dynamic (CFD) model with moving boundaries to study the intraventricular flows in a patient-specific framework. Starting from the segmentation of real-time transesophageal echocardiographic images, a CFD model including the complete left ventricle and the moving 3D mitral valve was realized. Their motion, known as a function of time from the segmented ultrasound images, was imposed as a boundary condition in an Arbitrary Lagrangian-Eulerian framework. Results: The model allowed for a realistic description of the displacement of the structures of interest and for an effective analysis of the intraventricular flows throughout the cardiac cycle. The model provides detailed intraventricular flow features, and highlights the importance of the 3D valve apparatus for the vortex dynamics and apical flow. Conclusions: The proposed method could describe the haemodynamics of the left ventricle during the cardiac cycle. The methodology might therefore be of particular importance in patient treatment planning to assess the impact of mitral valve treatment on intraventricular flow dynamics

Spatial and social mobility in England and Wales: A sub‐national analysis of differences and trends over time

Recent studies of social mobility have documented that not only who your parents are, but also where you grow up, substantially influences subsequent life chances. We bring these two concepts together to study social mobility in England and Wales, in three post-war generations, using linked Decennial Census data. Our findings show considerable spatial variation in rates of absolute and relative mobility, as well as how these have changed over time. While upward mobility increased in every region between the mid-1950s and the early 1980s, this shift varied across different regions and tailed off for more recent cohorts. We also explore how domestic migration is related to social mobility, finding that those who moved out of their region of origin had higher rates of upward mobility compared to those who stayed, although this difference narrowed over time

User acceptance of intelligent avionics: A study of automatic-aided target recognition

User acceptance of new support systems typically was evaluated after the systems were specified, designed, and built. The current study attempts to assess user acceptance of an Automatic-Aided Target Recognition (ATR) system using an emulation of such a proposed system. The detection accuracy and false alarm level of the ATR system were varied systematically, and subjects rated the tactical value of systems exhibiting different performance levels. Both detection accuracy and false alarm level affected the subjects' ratings. The data from two experiments suggest a cut-off point in ATR performance below which the subjects saw little tactical value in the system. An ATR system seems to have obvious tactical value only if it functions at a correct detection rate of 0.7 or better with a false alarm level of 0.167 false alarms per square degree or fewer

Spatial and social mobility in England and Wales: a sub-national analysis of differences and trends over time

Recent studies of social mobility have documented that not only who your parents are, but also where you grow up, substantially influences subsequent life chances. We bring these two concepts together to study social mobility in England and Wales, in three post-war generations, using linked Decennial Census data. Our findings show considerable spatial variation in rates of absolute and relative mobility, as well as how these have changed over time. While upward mobility increased in every region between the mid-1950s and the early 1980s, this shift varied across different regions and tailed off for more recent cohorts. We also explore how domestic migration is related to social mobility, finding that those who moved out of their region of origin had higher rates of upward mobility compared to those who stayed, although this difference narrowed over time

Optimal Moments for the Analysis of Peculiar Velocity Surveys

We present a new method for the analysis of peculiar velocity surveys which removes contributions to velocities from small scale, nonlinear velocity modes while retaining information about large scale motions. Our method utilizes Karhunen--Lo\`eve methods of data compression to construct a set of moments out of the velocities which are minimally sensitive to small scale power. The set of moments are then used in a likelihood analysis. We develop criteria for the selection of moments, as well as a statistic to quantify the overall sensitivity of a set of moments to small scale power. Although we discuss our method in the context of peculiar velocity surveys, it may also prove useful in other situations where data filtering is required.Comment: 25 Pages, 3 figures. Submitted to Ap

Ethnic differences in intergenerational housing mobility in England and Wales

Home ownership is the largest component of wealth for most households and its intergenerational transmission underpins the production and reproduction of economic inequalities across generations. Yet, little is currently known about ethnic differences in the intergenerational transmission of housing tenure. In this paper we use linked Census data covering 1971-2011 to document rates of intergenerational housing tenure mobility across ethnic groups in England and Wales. We find that while home ownership declined across all ethnic groups during this period, there were substantial differences between them. Black, Pakistani and Bangladeshi households experienced the strongest intergenerational link between parent and child housing tenure, and Black individuals had the highest rates of downward housing mobility. In contrast, those of Indian origin had homeownership rates similar to White British families, and a weaker link between parent and child housing tenure. These patterns are likely to exacerbate existing gradients in other dimensions of ethnicity-based inequality, now and in the future

Patient-specific CFD models for intraventricular flow analysis from 3D ultrasound imaging : comparison of three clinical cases

Background: As the intracardiac flow field is affected by changes in shape and motility of the heart, intraventricular flow features can provide diagnostic indications. Ventricular flow patterns differ depending on the cardiac condition and the exploration of different clinical cases can provide insights into how flow fields alter in different pathologies. Methods: In this study, we applied a patient-specific computational fluid dynamics model of the left ventricle and mitral valve, with prescribed moving boundaries based on transesophageal ultrasound images for three cardiac pathologies, to verify the abnormal flow patterns in impaired hearts. One case (P1) had normal ejection fraction but low stroke volume and cardiac output, P2 showed low stroke volume and reduced ejection fraction, P3 had a dilated ventricle and reduced ejection fraction. Results: The shape of the ventricle and mitral valve, together with the pathology influence the flow field in the left ventricle, leading to distinct flow features. Of particular interest is the pattern of the vortex formation and evolution, influenced by the valvular orifice and the ventricular shape. The base-to-apex pressure difference of maximum 2 mmHg is consistent with reported data. Conclusion: We used a CFD model with prescribed boundary motion to describe the intraventricular flow field in three patients with impaired diastolic function. The calculated intraventricular flow dynamics are consistent with the diagnostic patient records and highlight the differences between the different cases. The integration of clinical images and computational techniques, therefore, allows for a deeper investigation intraventricular hemodynamics in patho-physiology. (C) 2016 Elsevier Ltd. All rights reserved

Environmental Dependence of the Fundamental Plane of Galaxy Clusters

Galaxy clusters approximate a planar (FP) distribution in a three-dimensional parameter space which can be characterized by optical luminosity, half-light radius, and X-ray luminosity. Using a high-quality catalog of cluster redshifts, we find the nearest neighbor cluster for those common to an FP study and the cluster catalog. Examining scatter about the FP, we find 99.2% confidence that it is dependent on nearest neighbor distance. Our study of X-Ray clusters finds that those with high central gas densities are systematically closer to neighbor clusters. If we combine results here with those of Fritsch and Buchert, we find an explanation for some of our previous conclusions: Clusters in close proximity to other clusters are more likely to have massive cooling flows because they are more relaxed and have higher central gas densities.Comment: Accepted for publication in Astrophysical Journal Letters. Moderate revisions, including more statistical analysis and discussion. Latex, 7 page

Effectively Utilizing Undergraduate Teaching Fellows for Optimal Learning Environment

Undergraduate Teaching Fellows focus on working with students in class and outside of class in efforts of boosting confidence in study techniques and learning objectives in the curriculum. Knowing that there is another person who is not only close in age, but in their undergraduate pursuit, provides more comfort in being able to discuss concerns on the coursework. It allows for students to be more active in their academics and promotes an inclusive environment in the classroom. In class, UTFs have the capability of applying creativity in producing lesson plans and activities that allow students to be interactive, allowing for more retention of the material. Many students in our introductory math classes do not know how to be the best college student, but with the help of our UTFs, these students have a mentor who will help them through any obstacles they will face in their undergraduate career.https://digitalscholarship.unlv.edu/btp_expo/1096/thumbnail.jp