A System for Compressive Sensing Signal Reconstruction

An architecture for hardware realization of a system for sparse signal reconstruction is presented. The threshold based reconstruction method is considered, which is further modified in this paper to reduce the system complexity in order to provide easier hardware realization. Instead of using the partial random Fourier transform matrix, the minimization problem is reformulated using only the triangular R matrix from the QR decomposition. The triangular R matrix can be efficiently implemented in hardware without calculating the orthogonal Q matrix. A flexible and scalable realization of matrix R is proposed, such that the size of R changes with the number of available samples and sparsity level.Comment: 6 page

Fluid flow and heat transfer in a helium gas spring -computational fluid dynamics and experiments-

The employment of piston compression machines is today extremely wide and versatile.\ud Examples span from common household refrigerators, or internal combustion engines, to\ud highly efficient cryogenic compressors of all sizes and constructions for medical, military\ud and space applications. It is therefore not difficult to grasp the continuing search for the\ud outmost optimization of their efficiency and performance, elimination of any losses and\ud unneeded by-products, and improvements in predictability of their operation.\ud To further add to these requirements, many state-of-the-art compression technologies\ud move towards lubricant-free solutions in order to maintain the purity of the used\ud operating mediums and so improve the output and availability of their machinery. For this,\ud additional high efforts need to be put in providing and securing narrow tolerance windows\ud of utilized parts and their high stability.\ud With this thesis and the underlying research, the author attempts to add to the above\ud stated efforts. The work focuses on the fluid flow and heat transfer processes, and the\ud related thermodynamic phenomena occurring in a compressed fluid and at the fluid-wall\ud boundaries of an experimental valveless, unlubricated, one-cylinder piston gas spring.\ud The presented work is concentrated in three main directions – the experimental work,\ud numerical simulations, and analytical correlating. An experimental machine is newly\ud developed for the needs of this project and equipped with advanced measuring and data\ud acquisition equipment. Experimental data is collected, processed and presented over a\ud range of operating frequencies and two compression ratios. Computational Fluid\ud Dynamics (CFD) models are successfully developed for the numerical work, in order to\ud investigate the applicability of the existing numerical tools for capturing complex\ud processes such as those occurring in the piston compression machines. Full compression cycles with no in- and out- flows are modelled. Results are compared and discussed\ud together with the experimentally obtained sets and general thermodynamics principles.\ud Finally, analytical models are investigated and adjusted for several thermodynamic\ud parameters such as the cyclic compression loss, complex Nusselt number, or the thickness\ud of the thermal boundary layers during compression and expansion.\ud Book in front of you should not be seen as an attempt to present sets of design rules for\ud the piston compression machinery. It is rather a comprehensive summary of the prior\ud existing and newly pursued explorative work in the areas of experimental techniques,\ud numerical modelling and analytical analyses, applicable for capturing the gas-solid heat\ud transfer and fluid-flow processes in gas springs. It should also serve as a useful base for\ud defining additional research efforts, further aiming towards wider industrial applications

Experimental Models of Brain Hemorrhage Using Clostridial Collagenase

Stroke is the third leading cause of death and is the leading cause of disability in the United States, and the most severe form is known as intracerebral hemorrhage, which is bleeding into the brain. The goal of this study is to establish novel animal models to buildup foundations for translational research of intracerebral hemorrhage. We, for the first time, established four animal models, including cerebellum hemorrhage, pontine hemorrhage, neonatal matrix hemorrhage and maternal postpartum hemorrhage. Those models are established according to intracerebral hemorrhage patient subpopulations, and characterized the neurobehavioral and morphological outcomes. These studies have established the requisite for future translational work to test neuroprotective drugs with the aim of improving the quality of life for these vulnerable patient populations

Perceptions and Attitudes of Selected Adventist and non-Adventist Parents of School-Age Children Toward Adventist Schools in Canada

Purpose of the Study. The purpose of this study was to investigate the perceptions and attitudes toward Adventist schools in Canada of Adventist parents with children in Adventist schools, of Adventist parents without children in Adventist schools, and of non-Adventist parents who at the time of this study had children in Adventist schools, and to look for reasons why these parents send or do not send their children to Adventist schools in Canada. Method. The Adventist Education in Canada Parents\u27 Attitude Survey was developed and used to gather information about spiritual focus, academic excellence, school accessibility, administrators and teachers, interpersonal relationships and student personal development, and safe learning environment, and to discover why certain parents send or do not send their children to Adventist schools. The population surveyed provided 1,389 usable responses, which were analyzed by descriptive statistics, t -test, analysis of variance (ANOVA), and test of correlation coefficient. Each of the 12 hypotheses was tested at an alpha level of .05, except for school accessibility (.008). Results. Non-Adventist parents, especially mothers, had more positive attitudes toward Adventist schools than did both Adventist parents with or without children in Adventist schools. Furthermore, younger, single parents, earning less than CAD $30,000 a year and unemployed, were more positive than older, married parents, earning more and employed. Spiritual focus was perceived as the most positive aspect of Adventist schools, followed closely by interpersonal relationships and student personal development. For Adventist parents, three main reasons for sending children to Adventist schools were: spiritual focus, safe and caring environment, and dedicated school personnel; for non-Adventist parents, safe and caring environment, high-quality academics, and spiritual focus. Adventist parents not sending children to Adventist schools gave the following reasons: distance from home, high tuition cost, and lack of high-quality academics. Conclusions. Parents perceived Adventist schools in Canada as places where spiritual focus, interpersonal relationships and student personal development are strong; where safe learning environments exist; and where school administrators and teachers are fair and committed to the principles of Adventist education. Areas of concern were: affordability, bullying, extracurricular activities, facilities, variety of resources, and provisions for special education students

Geo-neutrinos and Earth Models

We present the current status of geo-neutrino measurements and their implications for radiogenic heating in the mantle. Earth models predict different levels of radiogenic heating and, therefore, different geo-neutrino fluxes from the mantle. Seismic tomography reveals features in the deep mantle possibly correlated with radiogenic heating and causing spatial variations in the mantle geo-neutrino flux at the Earth surface. An ocean-based observatory offers the greatest sensitivity to the mantle flux and potential for resolving Earth models and mantle features. Refinements to estimates of the geo-neutrino flux from continental crust reduce uncertainty in measurements of the mantle flux, especially measurements from land-based observatories. These refinements enable the resolution of Earth models using the combined measurements from multiple continental observatories.Comment: 9 pages, 4 figures; Contributed paper TAUP 201

Morphology of seismically slow lower-mantle structures

Large low shear velocity provinces (LLSVPs), whose origin and dynamic implication remain enigmatic, dominate the lowermost mantle. For decades, seismologists have created increasingly detailed pictures of the LLSVPs through tomographic models constructed with different modeling methodologies, data sets, parametrizations and regularizations. Here, we extend the cluster analysis methodology of Lekic $\textit{et al.}$, to classify seismic mantle structure in five recent global shear wave speed ($\textit{V}_S$) tomographic models into three groups. By restricting the analysis to moving depth windows of the radial profiles of $\textit{V}_S$, we assess the vertical extent of features. We also show that three clusters are better than two (or four) when representing the entire lower mantle, as the boundaries of the three clusters more closely follow regions of high lateral $\textit{V}_S$ gradients. Qualitatively, we relate the anomalously slow cluster to the LLSVPs, the anomalously fast cluster to slab material entering the lower mantle and the neutral cluster to ‘background’ lower mantle material. We obtain compatible results by repeating the analysis on recent global $\textit{P}$-wave speed ($\textit{V}_P$) models, although we find less agreement across $\textit{V}_P$ models. We systematically show that the clustering results, even in detail, agree remarkably well with a wide range of local waveform studies. This suggests that the two LLSVPs consist of multiple internal anomalies with a wide variety of morphologies, including shallowly to steeply sloping, and even overhanging, boundaries. Additionally, there are indications of previously unrecognized meso-scale features, which, like the Perm anomaly, are separated from the two main LLSVPs beneath the Pacific and Africa. The observed wide variety of structure size and morphology offers a challenge to recreate in geodynamic models; potentially, the variety can result from various degrees of mixing of several compositionally distinct components. Finally, we obtain new, much larger estimates of the volume/mass occupied by LLSVPs— 8.0 per cent ±0.9 ($\mu$ ± 1$\sigma$) of whole mantle volume and 9.1 per cent ±1.0 ($\mu$ ± 1$\sigma$) of whole mantle mass—and discuss implications for associating the LLSVPs with the hidden reservoir enriched in heat producing elements.National Science Foundation (EAR1352214), Packard Foundation, Pembroke College, Cambridge (Drapers’ Company Research Fellowship

Posterior Circulation Stroke: Animal Models and Mechanism of Disease

Posterior circulation stroke refers to the vascular occlusion or bleeding, arising from the vertebrobasilar vasculature of the brain. Clinical studies show that individuals who experience posterior circulation stroke will develop significant brain injury, neurologic dysfunction, or death. Yet the therapeutic needs of this patient subpopulation remain largely unknown. Thus understanding the causative factors and the pathogenesis of brain damage is important, if posterior circulation stroke is to be prevented or treated. Appropriate animal models are necessary to achieve this understanding. This paper critically integrates the neurovascular and pathophysiological features gleaned from posterior circulation stroke animal models into clinical correlations