The Anatomy of an Entrepreneur: Family Background and Motivation

Examines the socioeconomic, educational, familial, and professional backgrounds of entrepreneurs in high-growth industries, their motivations for becoming entrepreneurs, and their beliefs. Explores the correlations between factors

Exposure to innovation influences who becomes an inventor

Relatively little is known about the factors that induce people to become inventors

Accurate depth from defocus estimation with video-rate implementation

The science of measuring depth from images at video rate using „defocus‟ has been investigated. The method required two differently focussed images acquired from a single view point using a single camera. The relative blur between the images was used to determine the in-focus axial points of each pixel and hence depth. The depth estimation algorithm researched by Watanabe and Nayar was employed to recover the depth estimates, but the broadband filters, referred as the Rational filters were designed using a new procedure: the Two Step Polynomial Approach. The filters designed by the new model were largely insensitive to object texture and were shown to model the blur more precisely than the previous method. Experiments with real planar images demonstrated a maximum RMS depth error of 1.18% for the proposed filters, compared to 1.54% for the previous design. The researched software program required five 2D convolutions to be processed in parallel and these convolutions were effectively implemented on a FPGA using a two channel, five stage pipelined architecture, however the precision of the filter coefficients and the variables had to be limited within the processor. The number of multipliers required for each convolution was reduced from 49 to 10 (79.5% reduction) using a Triangular design procedure. Experimental results suggested that the pipelined processor provided depth estimates comparable in accuracy to the full precision Matlab‟s output, and generated depth maps of size 400 x 400 pixels in 13.06msec, that is faster than the video rate. The defocused images (near and far-focused) were optically registered for magnification using Telecentric optics. A frequency domain approach based on phase correlation was employed to measure the radial shifts due to magnification and also to optimally position the external aperture. The telecentric optics ensured pixel to pixel registration between the defocused images was correct and provided more accurate depth estimates

Biology of the Striped Bass, Morone saxatilis, in Beaver Reservoir, Arkansas

Growth, length-weight relationship, maturation and food habits of striped bass from Beaver Reservoir were studied. No significant difference in growth in length between sexes was found. Growth of the Beaver Reservoir striped bass was similar to that of anadromous and freshwater populations. Males and females showed significant difference in length-weight relationship, and females exhibited isometric growth. The gonosomatic indices (GSI) of males ranged from 4.50 to 7.09 and were classified as mature fish. Female striped bass with GSI of 2.62 and above had three size groups of ova and were considered as maturing and mature. The food was primarily composed of gizzard shad. Both the possible impact of striped bass on the ecosystem of Beaver Reservoir and future research are discussed

Timber harvesting on fragile ground and impacts of uncertainties in the operational costs

Forested wetlands with high water tables are sensitive to disruption from harvesting yet support commercially desired tree species like northern white-cedar. Winter harvest was conducted in Maine, USA, to compare operational costs and productivity of cut-to-length harvesting in cedar (fragile soil) and non-cedar stands (mixed wood, sturdy soil), evaluate uncertainties in harvesting costs and influential factors, and forecast time for post-harvest recovery to pre-harvest volumes. Operational costs were calculated using detailed time and motion studies. Operational costs for the cedar stands were higher than non-cedar. Regression models were developed for harvesters, forwarders, and self-loading trucks; number of logs per cycle was a common factor. Sensitivity analysis showed the dependence of operational costs on labor and fuel costs. Forest Vegetation Simulator projections were used to assess harvest sustainability and suggested the time required to regrow harvested merchantable volume is comparable to cutting cycles recommended for similar treatments in the region. Predicted growth rates exceed those reported regionally on similar sites, suggesting additional study of post-harvest response is warranted. Results highlight site constraints on both operational and stand productivity in lowlands and will be useful for timber harvesting decision-making and forest management planning if combined with assessment of residual stand growth response

Risk for Post-Spinal Surgery Complications Associated with Pre-Operative Blood Transfusions

Introduction: The frequency of spinal surgeries has increased dramatically in the United States over the past decade and, as with all surgeries, spinal procedures carry inherent risks for complications after the operation. Recently, it has been recognized that procedures in which intra-operative/post-operative blood transfusions are administered carry a higher risk of postoperative morbidity and increased length of hospital stay (Seisean et al.). Despite this, there is little literature, currently, analyzing post-operative complications associated with blood transfusions taking place 72 hours prior to spinal operations. The aim of this study was to investigate the prevalence of pre-operative blood transfusions in spinal surgeries and elucidate the associations that exist between those transfusions and post-operative complications. Materials & Methods: We retrospectively analyzed cases of spinal surgeries between 2005 and 2014 from the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database with the exception of 2009 due to incomplete data. A total of 37,201 patients who had undergone spinal procedures were studied. Patients receiving pre-operative blood transfusions within 72 hours of surgery were documented. Demographic factors, including sex and age, were noted. Comorbidities included in this analysis include body mass index (BMI) and American Society of Anesthesiologists (ASA) score. Post-operative complications were stratified into major and minor categories. Chi-squared test, Fisher\u27s exact test, and ANOVA were used to perform univariate testing where appropriate, while multivariate analyses were performed to determine independent risk factors for complications. Results:With the exception of pneumonia (p=0.096), blood transfusions prior to spinal surgeries were associated with increased risk for all major and minor complication criteria analyzed, with major complications including myocardial infarction (MI), deep venous thrombosis (DVT), pulmonary embolism (PE), stroke, peripheral nerve injury, deep wound infection, organ cavity infection, sepsis, and death (p Discussion: Overall, patients receiving blood transfusions within 72 hours prior to undergoing spinal procedures had increased rates of several post-operative complications. Among these complications, the most notable include superficial and deep wound infections, MI, pneumonia, DVT, stroke, and even death. Armed with this knowledge, surgeons would better be able to predict, and therefore mitigate, such post-operative complications in these patients. Future research in this area, directed toward stratification of risk based on the patient’s need for pre-operative blood transfusion and procedure type, would provide further insight into preventing post-operative complications after spinal surgeries

Accurate depth from defocus estimation with video-rate implementation

The science of measuring depth from images at video rate using „defocus‟ has been investigated. The method required two differently focussed images acquired from a single view point using a single camera. The relative blur between the images was used to determine the in-focus axial points of each pixel and hence depth. The depth estimation algorithm researched by Watanabe and Nayar was employed to recover the depth estimates, but the broadband filters, referred as the Rational filters were designed using a new procedure: the Two Step Polynomial Approach. The filters designed by the new model were largely insensitive to object texture and were shown to model the blur more precisely than the previous method. Experiments with real planar images demonstrated a maximum RMS depth error of 1.18% for the proposed filters, compared to 1.54% for the previous design. The researched software program required five 2D convolutions to be processed in parallel and these convolutions were effectively implemented on a FPGA using a two channel, five stage pipelined architecture, however the precision of the filter coefficients and the variables had to be limited within the processor. The number of multipliers required for each convolution was reduced from 49 to 10 (79.5% reduction) using a Triangular design procedure. Experimental results suggested that the pipelined processor provided depth estimates comparable in accuracy to the full precision Matlab‟s output, and generated depth maps of size 400 x 400 pixels in 13.06msec, that is faster than the video rate. The defocused images (near and far-focused) were optically registered for magnification using Telecentric optics. A frequency domain approach based on phase correlation was employed to measure the radial shifts due to magnification and also to optimally position the external aperture. The telecentric optics ensured pixel to pixel registration between the defocused images was correct and provided more accurate depth estimates.EThOS - Electronic Theses Online ServiceUniversity of Warwick (UoW)GBUnited Kingdo