RELIABILITY OF LOW-COST PORTABLE FORCE PLATFORMS FOR MEASURING VERTICAL STIFFNESS DURING RUNNING

Ground reaction force (GRF) can provide useful information such as vertical stiffness (Kvert) to practitioners working with runners and sprinters, but high equipment costs are hindering applied research. Low-cost portable force platforms may be a useful alternative to traditional biomechanical equipment. Moderately trained runners (n = 9) completed overground running trials at various speeds (2.15-5.78 m/s), Kvert was determined, and a linear regression was used to characterize the relationship between Kvert and running speed. The results showed moderate to high correlation (r2 = 0.54 to 0.87). At 3.9 m/s (14 km/h), the widest regression model confidence interval was 4.4%, which shows this procedure likely provides adequate reliability. Future research should continue to investigate the use of low-cost portable force platforms for measuring running GRF

HEAD IMPACT FREQUENCY IN YOUTH AMERICAN FOOTBALL, AGES 9-13

The objective of this study was to quantify head impact frequency in youth American football players, ages 9-13. Kinematic data from head impacts were collected from 25 players on two teams (11.7 ± 1.2 years) using a helmet-mounted accelerometer system. A total of 4432 head impacts were recorded, including 1800 during 265 practice sessions and 2632 during 175 game sessions. Most peak linear acceleration magnitudes were less than 20 g in practices (60%) and games (55%). For impacts greater than or equal to 60 g, players sustained 122% more in games than practices. Both teams played in leagues that limited full-contact practice time, which likely contributed to lower impact frequencies in practices. Interventions to further reduce head impact frequency in youth football should include measures which affect in-game exposure

Experimental study of impulse turbines and permanent magnet alternators for pico-hydropower generation

Increasing access to modern forms of energy in developing countries is a crucial component to eliminating extreme poverty around the world. Pico-hydro schemes (less than 5-kW range) can provide environmentally sustainable electricity and mechanical power to rural communities, generally more cost-effectively than diesel/gasoline generators, wind turbines, or solar photovoltaic systems. The use of these types of systems has in the past and will continue in the future to have a large impact on rural, typically impoverished areas, allowing them the means for extended hours of productivity, new types of commerce, improved health care, and other services vital to building an economy. For this thesis, a laboratory-scale test fixture was constructed to test the operating performance characteristics of impulse turbines and electrical generators. Tests were carried out on a Pelton turbine, two Turgo turbines, and a permanent magnet alternator (PMA). The effect on turbine efficiency was determined for a number of parameters including: variations in speed ratio, jet misalignment and jet quality. Under the best conditions, the Turgo turbine efficiency was observed to be over 80% at a speed ratio of about 0.46, which is quite good for pico-hydro-scale turbines. The Pelton turbine was found to be less efficient with a peak of just over 70% at a speed ratio of about 0.43. The lower efficiency can be largely attributed to the rougher surface on the turbine blades. Both turbine types had lower than expected speed ratios which were likely caused by inefficiencies in the turbine. Tests of jet misalignment showed that moving the jet to the inside or outside edge of the buckets caused a drop in efficiency of around 10-20% as well as shifting the optimal speed ratio down 0.03 (6.5%). For the PMA, the generator efficiency peaked at just less than 70%. The data demonstrate the impact of impedance matching on generator efficiency for a PMA. Currently published literature provides few details specific to Turgo turbines or PMAs despite their suitability for pico-hydro. Nonetheless, Turgo turbines are currently available on the market (at least in the US) and offer a viable option for picohydro schemes, particularly in the medium head range. This thesis describes an experimental investigation of impulse turbines, including both Turgo and Pelton turbines, which will be useful for implementation of rural electrification projects. The results stress the importance of proper system design and installation in order to ensure a successful scheme

Open Retromuscular Repair of Parastomal Hernias

Faculty Mentor: Dr. Bill Pierc

Augmenting the Space Domain Awareness Ground Architecture via Decision Analysis and Multi-Objective Optimization

Purpose — The US Government is challenged to maintain pace as the world’s de facto provider of space object cataloging data. Augmenting capabilities with nontraditional sensors present an expeditious and low-cost improvement. However, the large tradespace and unexplored system of systems performance requirements pose a challenge to successful capitalization. This paper aims to better define and assess the utility of augmentation via a multi-disiplinary study. Design/methodology/approach — Hypothetical telescope architectures are modeled and simulated on two separate days, then evaluated against performance measures and constraints using multi-objective optimization in a heuristic algorithm. Decision analysis and Pareto optimality identifies a set of high-performing architectures while preserving decision-maker design flexibility. Findings — Capacity, coverage and maximum time unobserved are recommended as key performance measures. A total of 187 out of 1017 architectures were identified as top performers. A total of 29% of the sensors considered are found in over 80% of the top architectures. Additional considerations further reduce the tradespace to 19 best choices which collect an average of 49–51 observations per space object with a 595–630 min average maximum time unobserved, providing redundant coverage of the Geosynchronous Orbit belt. This represents a three-fold increase in capacity and coverage and a 2 h (16%) decrease in the maximum time unobserved compared to the baseline government-only architecture as-modeled. Originality/value — This study validates the utility of an augmented network concept using a physics-based model and modern analytical techniques. It objectively responds to policy mandating cataloging improvements without relying solely on expert-derived point solutions

An International Multicenter Performance Analysis of Cytomegalovirus Load Tests

A new quantitative polymerase chain reaction assay, COBAS AmpliPrep/COBAS TaqMan CMV Test, was developed using the first World Health Organization cytomegalovirus standard. It demonstrated a high level of interlaboratory agreement and precision compared to quantitative results obtained with tests used by 5 different laboratorie

Academic Placement Data and Analysis: 2016 Final Report

Academic Placement Data and Analysis (APDA), a project funded by the American Philosophical Association (APA) and headed by Carolyn Dicey Jennings (UC Merced), aims “to make information on academic job placement useful to prospective graduate students in philosophy.” The project has just been updated to include new data, which Professor Jennings describes in a post at New APPS. She also announces a new interactive data tool with which one can sift through and sort information. (from Daily Nous

Head Impact Exposure in Youth Football: Elementary School Ages 9–12 Years and the Effect of Practice Structure

Head impact exposure in youth football has not been well-documented, despite children under the age of 14 accounting for 70% of all football players in the United States. The objective of this study was to quantify the head impact exposure of youth football players, age 9–12, for all practices and games over the course of single season. A total of 50 players (age = 11.0 ± 1.1 years) on three teams were equipped with helmet mounted accelerometer arrays, which monitored each impact players sustained during practices and games. During the season, 11,978 impacts were recorded for this age group. Players averaged 240 ± 147 impacts for the season with linear and rotational 95th percentile magnitudes of 43 ± 7 g and 2034 ± 361 rad/s(2). Overall, practice and game sessions involved similar impact frequencies and magnitudes. One of the three teams however, had substantially fewer impacts per practice and lower 95th percentile magnitudes in practices due to a concerted effort to limit contact in practices. The same team also participated in fewer practices, further reducing the number of impacts each player experienced in practice. Head impact exposures in games showed no statistical difference. While the acceleration magnitudes among 9–12 year old players tended to be lower than those reported for older players, some recorded high magnitude impacts were similar to those seen at the high school and college level. Head impact exposure in youth football may be appreciably reduced by limiting contact in practices. Further research is required to assess whether such a reduction in head impact exposure will result in a reduction in concussion incidence

Biochemical characterization of the skeletal matrix of the massive coral, Porites australiensis – The saccharide moieties and their localization

To construct calcium carbonate skeletons of sophisticated architecture, scleractinian corals secrete an extracellular skeletal organic matrix (SOM) from aboral ectodermal cells. The SOM, which is composed of proteins, saccharides, and lipids, performs functions critical for skeleton formation. Even though polysaccharides constitute the major component of the SOM, its contribution to coral skeleton formation is poorly understood. To this end, we analyzed the SOM of the massive colonial coral, Porites australiensis, the skeleton of which has drawn great research interest because it records environmental conditions throughout the life of the colony. The coral skeleton was extensively cleaned, decalcified with acetic acid, and organic fractions were separated based on solubility. These fractions were analyzed using various techniques, including SDS-PAGE, FT-IR, in vitro crystallization, CHNS analysis, chromatography analysis of monosaccharide and enzyme-linked lectin assay (ELLA). We confirmed the acidic nature of SOM and the presence of sulphate, which is thought to initiate CaCO3 crystallization. In order to analyze glycan structures, we performed ELLA on the soluble SOM for the first time and found that it exhibits strong specificity to Datura stramonium lectin (DSL). Furthermore, using biotinylated DSL with anti-biotin antibody conjugated to nanogold, in situ localization of DSL-binding polysaccharides in the P. australiensis skeleton was performed. Signals were distributed on the surfaces of fiber-like crystals of the skeleton, suggesting that polysaccharides may modulate crystal shape. Our study emphasizes the importance of sugar moieties in biomineralization of scleractinian corals

Estimates of the prevalence of rheumatic diseases in the population of Tecumseh, Michigan, 1959-60

Over 90 per cent of the more than 9000 residents of Tecumseh, Michigan participated in a program of comprehensive health examinations in 1959-1960. Included in the examination were inquiries regarding rheumatic symptoms, physical examination of the spine and peripheral joints, and the latex fixation test for rheumatoid factor and serum uric acid measurement.Joint pain or aching, joint swelling, morning stiffness, and past arthritis or rheumatism were common complaints, occurring in one-eighth to one-third of the population age 6 yr and over. The age-sex specific prevalence rates for each of these historical items rose with increasing age. Male and female rates were quite similar during the first four decades of life, but thereafter female rates were somewhat higher.The prevalence of positive latex fixation tests for rheumatoid factor was essentially the same for male and female subjects, 3.4 per cent for males and 3.35 per cent for females. The rates rose progressively from approximately one per cent in the 6-16 yr age group to almost 14 per cent for males and 9.4 per cent for females in the oldest age groups. The latex fixation test performed poorly as a case detection tool, only one-third of those respondents with positive tests having any other evidence to suggest a diagnosis of rheumatoid arthritis. Relatively high rates of latex positively occurred in individuals with a history of jaundice or infectious hepatitis and in those with evidence of emphysema or right heart failure. None of the respondents with psoriasis or pregnancy at the time of examination had positive latex tests. The prevalence of latex positivity showed a rise with increasing systolic blood pressure in persons over 30 yr of age, but appeared to be unrelated to diastolic blood pressure, serum cholesterol or serum uric acid.Prevalence rates for "definite" rheumatoid arthritis, based on the diagnostic criteria proposed by the American Rheumatism Association, were 0.4 per cent for all subjects age 6 yr and over and 0.5 per cent for all subjects age 16 yr and over. Prevalence rates for "definite" plus "probable" rheumatoid arthritis were 1.3 per cent in the age group 6 yr and over and 1.7 per cent in the age group 16 yr and over. In all diagnostic categories prevalence rates for females exceeded those for males. In the age group 16 yr and over the female to male ratio was 2.3: 1 for "definite" disease and 2.4: 1 for total suspected cases of rheumatoid arthritis. The prevalence rates for rheumatoid arthritis rose with increasing age; rates for "definite" disease rose from 0.44 per cent in the fourth decade to 0.79 per cent in the eighth decade for males and from 1.69 per cent in the fifth decade to 2.47 per cent in the eighth decade for females.The over-all prevalence rates for suspected ankylosing spondylitis, not confirmed by X-ray examination of the spine or sacroiliac joints, were 0.4 per cent for males and 0.05 per cent for females age 6 yr and over.Prevalence rates for osteoarthritis, diagnosed on the basis of physical rather than radiological examination were 2.2 per cent for males and 5.0 per cent for females age 6 yr and over. Rates were highest in the older age groups, being 20.3 per cent for males and 40.8 per cent for females in the age group 60 yr and over. The prevalence of Heberden's nodes was greater in female than in male respondents and demonstrated a similar rise with increasing age.The prevalence of "probable" gout, based on available clinical information was 0.5 per cent for male and 0.3 per cent for female subjects age 4 yr and over having serum uric acid determinations. The highest rates were observed in subjects in the age range 40-59 yr.The prevalence rates for a history of rheumatic fever and / or chorea were similar for male and female subjects age 6 yr and over, 0.8 per cent in the case of rheumatic fever and 0.1 per cent in the case of chorea. A history of chorea was not obtained among respondents under age 20. Physical evidence of rheumatic heart disease was recorded in all age groups and was slightly more prevalent in females, 0.6 per cent as compared to 0.4 per cent in males.Comparisons of the results of this investigation with those of other population studies have been made although the interpretation of any differences or similarities is inherently limited by methodological problems and observer variation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33324/1/0000720.pd