Automated precision passing system

Athletes are always seeking ways to improve their performance. Down time and a lack of capable throwers prevent athletic receivers from practicing their skills. We hope to aid athletes in receiving drills within their respective sports and increase practice efficiency. In order to achieve this, the machine has one major axis of rotation driven by a motor. This enables it to adjust where the ball is being thrown. Using an Arduino Uno coupled with a Roboteq AX1500 motor driver, the Automated Precision Passing System is able to throw a ball to a specified point in space by adjusting both the azimuth and ball-throwing motor speed. Our testing shows that our prototype has the ability to position itself in three different orientations as well as adjust the launch motor speed, but we were unable to launch the ball the original distance that we desired. From this project, we gained valuable knowledge in the areas of machine design, control systems, and project management. In order to continue the project and create a functional consumer product there are several improvements that need to be made to the system. The Automated Precision Passing System needs to be more rigid, have more power, and include more throwing positions

A cross-cultural study of suicide in twenty-three pre-literate societies

Thesis (M.S.)--Boston Universit

Stable Unitary Integrators for the Numerical Implementation of Continuous Unitary Transformations

The technique of continuous unitary transformations has recently been used to provide physical insight into a diverse array of quantum mechanical systems. However, the question of how to best numerically implement the flow equations has received little attention. The most immediately apparent approach, using standard Runge-Kutta numerical integration algorithms, suffers from both severe inefficiency due to stiffness and the loss of unitarity. After reviewing the formalism of continuous unitary transformations and Wegner's original choice for the infinitesimal generator of the flow, we present a number of approaches to resolving these issues including a choice of generator which induces what we call the "uniform tangent decay flow" and three numerical integrators specifically designed to perform continuous unitary transformations efficiently while preserving the unitarity of flow. We conclude by applying one of the flow algorithms to a simple calculation that visually demonstrates the many-body localization transition.Comment: 13 pages, 4 figures, Comments welcom

Multiple-scale structures: from Faraday waves to soft-matter quasicrystals

For many years, quasicrystals were observed only as solid-state metallic alloys, yet current research is now actively exploring their formation in a variety of soft materials, including systems of macromolecules, nanoparticles and colloids. Much effort is being invested in understanding the thermodynamic properties of these soft-matter quasicrystals in order to predict and possibly control the structures that form, and hopefully to shed light on the broader yet unresolved general questions of quasicrystal formation and stability. Moreover, the ability to control the self-assembly of soft quasicrystals may contribute to the development of novel photonic or other applications based on self-assembled metamaterials. Here a path is followed, leading to quantitative stability predictions, that starts with a model developed two decades ago to treat the formation of multiple-scale quasiperiodic Faraday waves (standing wave patterns in vibrated fluid surfaces) and which was later mapped onto systems of soft particles, interacting via multiple-scale pair potentials. The article reviews, and substantially expands, the quantitative predictions of these models, while correcting a few discrepancies in earlier calculations, and presents new analytical methods for treating the models. In so doing, a number of new stable quasicrystalline structures with octagonal, octadecagonal and higher-order symmetries, some of which may, it is hoped, be observed in future experiments.Comment: 22 pages, 22 figures, 1 table. Comments welcom

Assessment of acute headache in adults - what the general physician needs to know.

Headache is common. Up to 5% of attendances to emergency departments and acute medical units are due to headache. Headache is classified as either primary (eg migraine, cluster headache) or secondary to another cause (eg meningitis, subarachnoid haemorrhage). Even in the acute setting the majority of cases are due to primary causes. The role of the attending physician is to take a comprehensive history to diagnose and treat benign headache syndromes while ruling out sinister aetiologies. This brief article summarises the approach to assessment of headache presenting in acute and emergency care

Using Professionally Trained Interpreters to Increase Patient/Provider Satisfaction: Does It Work?

Examines the need for trained medical interpreters by comparing the satisfaction of emergency room patients, doctors, and triage and discharge nurses when provided with interpreters and when provided only with telephone language lines or ad hoc services

Exposure to perfluoroalkyl acids and markers of kidney function among children and adolescents living near a chemical plant.

BACKGROUND: Serum levels of perfluorooctanoic acid (PFOA) have been associated with decreased renal function in cross-sectional analyses, but the direction of the association is unclear. OBJECTIVES: We examined the association of measured and model-predicted serum PFOA concentrations with estimated glomerular filtration rate (eGFR), a marker of kidney function, in a highly exposed population (median serum PFOA, 28.3 ng/mL). METHODS: We measured serum creatinine, PFOA, perfluorooctane sulfonate (PFOS), perfluorononanoic acid (PFNA), and perfluorohexane sulfonate (PFHxS) and calculated eGFR in 9,660 children 1 to < 18 years of age at study enrollment. We predicted concurrent and historical serum PFOA concentrations using a validated environmental, exposure, and pharmacokinetic model based on individual residential histories, and used linear regression to estimate the association between eGFR and measured and predicted serum PFOA concentrations. We hypothesized that predicted serum PFOA levels would be less susceptible to reverse causation than measured levels. RESULTS: An interquartile range increase in measured serum PFOA concentrations [IQR ln(PFOA) = 1.63] was associated with a decrease in eGFR of 0.75 mL/min/1.73 m(2) (95% CI: -1.41, -0.10; p = 0.02). Measured serum levels of PFOS, PFNA, and PFHxS were also cross-sectionally associated with decreased eGFR. In contrast, predicted serum PFOA concentrations at the time of enrollment were not associated with eGFR (-0.10; 95% CI: -0.80, 0.60; p = 0.78). Additionally, predicted serum PFOA levels at birth and during the first ten years of life were not related to eGFR. CONCLUSIONS: Our findings suggest that the cross-sectional association between eGFR and serum PFOA observed in this and prior studies may be a consequence of, rather than a cause of, decreased kidney function