Automatic Merging of Lidar Point-Clouds Using Data from Low-Cost GPS/IMU Systems

Stationary lidar (Light Detection and Ranging) systems are often used to collect 3-D data (point clouds) that can be used for terrain modelling. The lidar gathers scans which are then merged together to map a terrain. Typically this is done using a variant of the well-known Iterated Closest Point (ICP) algorithm when position and pose of the lidar scanner is not accurately known. One difficulty with the ICP algorithms is that they can give poor results when points that are not common to both scans (outliers) are matched together. With the advent of MEMS (microelectromechanical systems)-based GPS/IMU systems, it is possible to gather coarse position and pose information at a low cost. This information is not accurate enough to merge point clouds directly, but can be used to assist the ICP algorithm during the merging process. This paper presents a method called Sphere Outlier Removal (SOR), which accurately identifies outliers and inliers, a necessary prerequisite to using the ICP algorithm. SOR incorporates the information from a low cost GPS/IMU to perform this identification. Examples are presented which illustrate the improvement in the accuracy of merged point clouds when the SOR algorithm is used

Epistemic decision theory applied to multiple-target tracking

A decision philosophy that seeks the avoidance of error by trading off belief of truth and value of information is applied to the problem of recognizing tracks from multiple targets (MTT). A successful MTT methodology should be robust in that its performance degrades gracefully as the conditions of the collection become less favorable to optimal operation. By stressing the avoidance, rather than the explicit minimization, of error, the authors obtain a decision rule for trajectory-data association that does not require the resolution of all conflicting hypotheses when the database does not contain sufficient information to do so reliably. This rule, coupled with a set-valued Kalman filter for trajectory estimation, results in a methodology that does not attempt to extract more information from the database than it contains

Blood Pressure and Cognitive Function in an African-American and a Caucasian-American Sample: The Maine-Syracuse Study

Objective: The primary purpose of this study was to examine associations between indices of blood pressure (BP) and cognitive function for African-American participants in the Maine-Syracuse Longitudinal Study (MSLS). Corresponding data for the Caucasian-American MSLS participants were included to provide a basis for comparison. Interactions of age with BP indices were also assessed in relation to cognitive function. Methods: Data were drawn from the baseline MSLS questionnaires, medical interviews and examinations, Wechsler Adult Intelligence Scale subtests, and measurements of BP for 1563 participants, of whom 147 were African American. Multiple linear regression analyses were employed to examine the relationship between several BP predictors and cognitive outcomes with statistical adjustment for demographic, psychosocial, and cardiovascular risk factors. Results: Significant inverse associations between BP indices and cognitive performance were obtained for both racial cohorts but were generally of higher magnitude for the African-American cohort. Interactions of BP with age were not obtained for any of the cognitive test scores. Conclusions: Elevations in BP are associated with poorer cognitive function for African-American and Caucasian-American cohorts. These associations are similar for younger and older participants

Bone health in patients undergoing surgery for primary hyperparathyroidism at Tygerberg Hospital, Cape Town, South Africa

Background: Increased bone resorption is a well-described consequence of primary hyperparathyroidism (PHPT). In South Africa, little is known about the impact of PHPT on skeletal health.Objective: To determine the prevalence of decreased bone mineral density (BMD), vertebral fractures and osteitis fibrosa cystica in patients with PHPT who underwent parathyroidectomy.Methods: Retrospective study of patients who underwent parathyroidectomy for PHPT at Tygerberg Hospital in Cape Town, from January 2010 to December 2019. Clinical, biochemical and BMD parameters are described.Results: Final analysis included 56 patients (median age 63.5 years; 80.4% female). Initial calcium, parathyroid hormone (PTH) and 25-hydroxyvitamin D (25[OH]D) levels were 2.93 mmol/l, 19.4 pmol/l and 34.0 nmol/l, respectively. Of the total cohort, 71.4% had decreased BMD. The prevalence of osteoporosis and osteopenia in postmenopausal women and men ≥ 50 years was 50.0% and 39.1% respectively; low bone mass for age in premenopausal women and men < 50 years was 20.0%. Vertebral fractures were seen in 21.2% of patients on radiography. Osteitis fibrosa cystica was present in five patients (9.6%). PTH levels were significantly elevated in patients with osteoporosis compared with those with normal BMD (36.4 vs. 16.1 pmol/l; p = 0.02).Conclusion: Two-thirds of patients who underwent parathyroidectomy for PHPT had decreased BMD, with osteoporosis present in 50% of postmenopausal women and older men. One in five had vertebral fractures. These findings underscore the importance of skeletal  assessment in the management of PHPT

Relation Between Central Adiposity and Cognitive Function in the Maine–Syracuse Study: Attenuation by Physical Activity

Background. Previous studies have demonstrated a relationship between central adiposity and cognitive function. However, only some of these studies have adjusted for cardiovascular risk factors and cardiovascular disease, and none have also adjusted for physical activity level. Purpose. The purpose of the study was to examine the association between anthropometric measures of central adiposity (waist circumference and waist/hip ratio) and cognitive functioning with adjustment for cardiovascular disease risk factors and physical activity. Methods. Participants were 917 stroke- and dementia-free community-dwelling adults (59% women) in the Maine– Syracuse Study. The design was cross-sectional. Outcome measures included tests from the Wechsler Adult Intelligence Scale, the Halstead-Reitan Neuropsychological Battery, the Wechsler Memory Scale Revised, and the Mini-Mental State Examination

Homocysteine, type 2 diabetes mellitus, and cognitive performance: The Maine-Syracuse Study

Type 2 diabetes mellitus and higher total plasma homocysteine concentrations are each associated with an increased incidence of cardiovascular disease and with diminished cognitive performance. Relations between homocysteine concentrations and cardiovascular disease incidence are stronger in the presence of type 2 diabetes mellitus. Therefore, we hypothesized that relations between homocysteine concentrations and cognitive performance would be stronger in the presence of type 2 diabetes. We related homocysteine concentrations and cognitive performance on the Mini-Mental State Examination in 817 dementia- and stroke-free participants of the Maine-Syracuse Study, 90 of whom were classified with type 2 diabetes mellitus. Regardless of statistical adjustment for age, sex, gender, vitamin co-factors (folate, vitamin B6, vitamin B12), cardiovascular disease risk factors, and duration and type of treatment for type 2 diabetes mellitus, statistically significant inverse associations between homocysteine concentrations and cognitive performance were observed for diabetic individuals. The weaker inverse associations between homocysteine concentrations and cognitive performance obtained for non-diabetic individuals were not robust to statistical adjustment for some covariates. Interactions between homocysteine concentrations and type 2 diabetes mellitus are observed such that associations between homocysteine and cognitive performance are stronger in the presence of diabetes

Non-Edible Plant Oils as New Sources for Biodiesel Production

Due to the concern on the availability of recoverable fossil fuel reserves and the environmental problems caused by the use those fossil fuels, considerable attention has been given to biodiesel production as an alternative to petrodiesel. However, as the biodiesel is produced from vegetable oils and animal fats, there are concerns that biodiesel feedstock may compete with food supply in the long-term. Hence, the recent focus is to find oil bearing plants that produce non-edible oils as the feedstock for biodiesel production. In this paper, two plant species, soapnut (Sapindus mukorossi) and jatropha (jatropha curcas, L.) are discussed as newer sources of oil for biodiesel production. Experimental analysis showed that both oils have great potential to be used as feedstock for biodiesel production. Fatty acid methyl ester (FAME) from cold pressed soapnut seed oil was envisaged as biodiesel source for the first time. Soapnut oil was found to have average of 9.1% free FA, 84.43% triglycerides, 4.88% sterol and 1.59% others. Jatropha oil contains approximately 14% free FA, approximately 5% higher than soapnut oil. Soapnut oil biodiesel contains approximately 85% unsaturated FA while jatropha oil biodiesel was found to have approximately 80% unsaturated FA. Oleic acid was found to be the dominant FA in both soapnut and jatropha biodiesel. Over 97% conversion to FAME was achieved for both soapnut and jatropha oil

Understanding State Preferences With Text As Data: Introducing the UN General Debate Corpus

Every year at the United Nations, member states deliver statements during the General Debate discussing major issues in world politics. These speeches provide invaluable information on governments’ perspectives and preferences on a wide range of issues, but have largely been overlooked in the study of international politics. This paper introduces a new dataset consisting of over 7,300 country statements from 1970-2014. We demonstrate how the UN General Debate Corpus (UNGDC) can be used to derive country positions on different policy dimensions using text analytic methods. The paper provides applications of these estimates, demonstrating the contribution the UNGDC can make to the study of international politics

Unzipping Kinetics of Double-Stranded DNA in a Nanopore

We studied the unzipping kinetics of single molecules of double-stranded DNA by pulling one of their two strands through a narrow protein pore. PCR analysis yielded the first direct proof of DNA unzipping in such a system. The time to unzip each molecule was inferred from the ionic current signature of DNA traversal. The distribution of times to unzip under various experimental conditions fit a simple kinetic model. Using this model, we estimated the enthalpy barriers to unzipping and the effective charge of a nucleotide in the pore, which was considerably smaller than previously assumed.Comment: 10 pages, 5 figures, Accepted: Physics Review Letter

Implementing environmental improvements in a manufacturing context: a structured approach for the precast concrete industry

In common with other industries, most of the measures and solutions employed by companies in the £2 billion UK precast concrete manufacturing sector are linked to profitability. The concept of sustainability adds new dimensions as social progress and environmental protection become end goals in themselves, rather than objectives to achieve economic growth. This paper explores the nature of the precast industry and discusses opportunities and challenges relating to environmental improvement. A holistic view of the manufacture and procurement of precast concrete products is used to offer environmental improvement criteria an enhanced status in relation to the profitability imperative