Magnetic Suspension and Balance Systems: A Comprehensive, Annotated Bibliography

This bibliography contains 301 entries. Results are reported of recent studies aimed at increasing the research capabilities of magnetic suspension and balance systems; e.g., increasing force and torque capability, increasing angle of attack capability, and increasing overall system reliability. The problem is addressed of scaling from the relatively small size of existing systems to much larger sizes. The purpose of the bibliography is to provide an up-to-date list of publications that might be helpful to persons interested in magnetic suspension and balance systems for use in wind tunnels. The arrangement is generally chronological by date of presentation. However, papers presented at conferences or meetings are placed under dates of presentation. The numbers assigned to many of the citations have been changed from those used in the previous bibliography. This has been done in order to allow outdated citations to be removed and some recently discovered older works to be included in their proper chronological order. Author, source, and subject indexes are included in order to increase the usefulness of this compilation

The Year Round Calendar: An Analysis of Student Outcomes

Almost a decade ago, the National Education Commission on Time and Learning warned Americans that schools were unable to meet the demands of a new global economy. For 150 years, schools had operated on schedules that suited only the top students, while average and poor students simply dropped out to make decent livings on farms or in factories

A Study of Problem Posing as a Means to Help Mathematics Teachers Foster Creativity

Research suggests that mathematical creativity often results from extended periods of mathematical activity and reflection based on the use of deep and flexible content knowledge [14, 15]. This implies that instruction can influence creativity. However, for teaching to foster creativity in mathematics, there should be purposefully designed instructional tasks. It is doubtful that routine, mechanical exercises would foster creativity. Moreover, mathematical creativity may neither be explicitly promoted, nor fully appreciated, by students when a learning space involves only problem solving, even if the problems are challenging and engaging. For students to get an authentic sense of mathematics and to develop habits that are more likely to lead to an appreciation of mathematical creativity, they need to experience both problem solving and problem posing, as both are “essential aspects of mathematical activity” [22, page 31]

Resurgence of Sleeping Sickness in Tambura County, Sudan

Endemic foci of human African trypanosomiasis are present in southern Sudan. In 1996 and 1997, trypanosomiasis increased sharply in Tambura County. To define the magnitude and geographic distribution of the outbreak, we conducted a prevalence survey using population-based cluster sampling in 16 villages: 1,358 participants answered questions about routine activities and tsetse fly contact and received serologic testing. Seroprevalence in the surveyed area was 19.4% (95% confidence interval = 16.9%, 21.8%). We confirmed infection in 66% of seropositive persons who received one parasitologic examination and in 95% of those who had serial examinations of lymph node fluid and blood. Activities related to the civil war, such as temporary migration, were not associated with seropositive status. Since the previous population screening in 1988, the trypanosomiasis prevalence increased two orders of magnitude, and the proportion of villages affected increased from 54% to 100%. Our results suggest that there may be 5,000 cases in Tambura County. The absence of trypanosomiasis control for nearly a decade is a factor in the resurgence of the disease

Filtration by oysters : interactive effects of water flow, seston composition and filtration rate

Filtration by suspension-feeding bivalves affects water quality and the postulated impacts include increased light penetration and enhanced benthic primary production. Such system-level predictions are extrapolated fiom still water experiments which neglect the effects of flow, seston composition, turbulent mixing and refiltration by oysters within groups. Flume experiments were used to investigate the effects of varying flow speed and seston composition on filtration capacity of oysters. Six groups of 90 oysters were used in treatments which varied concentrations of the algae Ekalassiosira weisj70grgrsie parately and in combination with inorganics; four sets of shell only controls were used to evaluate hydrodynamic effects. The results indicate the importance of morphological differences in bed structure on turbulence and particle redistribution which may obscure biological effects and of the importance of the physiological condition of oysters on filtration capacity. Field transplants of eelgrass, Zostera marina, and American oysters, Crassostrea virgmica, were used to evaluate interactions between oyster filtration, water quality and plant survival in the field. Abnormally poor water quality forced the early termination of these experiments, but in conjunction with the flume results they indicate a strong effect of physical forces on seston distribution against which impacts of suspension feeders must judged

The VWFA Is the Home of Orthographic Learning When Houses Are Used as Letters

Learning to read specializes a portion of the left mid-fusiform cortex for printed word recognition, the putative visual word form area (VWFA). This study examined whether a VWFA specialized for English is sufficiently malleable to support learning a perceptually atypical second writing system. The study utilized an artificial orthography, HouseFont, in which house images represent English phonemes. House images elicit category-biased activation in a spatially distinct brain region, the so-called parahippocampal place area (PPA). Using house images as letters made it possible to test whether the capacity for learning a second writing system involves neural territory that supports reading in the first writing system, or neural territory tuned for the visual features of the new orthography. Twelve human adults completed two weeks of training to establish basic HouseFont reading proficiency and underwent functional neuroimaging pre and post-training. Analysis of three functionally defined regions of interest (ROIs), the VWFA, and left and right PPA, found significant pre-training versus post-training increases in response to HouseFont words only in the VWFA. Analysis of the relationship between the behavioral and neural data found that activation changes from pre-training to post-training within the VWFA predicted HouseFont reading speed. These results demonstrate that learning a new orthography utilizes neural territory previously specialized by the acquisition of a native writing system. Further, they suggest VWFA engagement is driven by orthographic functionality and not the visual characteristics of graphemes, which informs the broader debate about the nature of category-specialized areas in visual association cortex

Associations of body mass index, physical activity and sedentary time with blood pressure in primary school children from south-west England: a prospective study

Elevated blood pressure in children is a significant risk factor for the development of cardiovascular disease in adulthood. We examined how children's body mass index (BMI), physical activity and sedentary time at ages 9 and 11 are associated with blood pressure at age 11. Data were from 1283 children from Bristol, UK, who participated in the study aged 11 years, 797 of whom also participated in the study aged 9 years. Child height, weight and blood pressure were measured, and children wore accelerometers for five days, from which moderate-to-vigorous-intensity physical activity and sedentary minutes per day were derived. Multiple imputation of missing data and adjusted linear and logistic regression models were used to examine associations. Child BMI at 11 years was cross-sectionally associated with higher systolic and diastolic blood pressure (mean difference [95% confidence interval]: 0.91 [0.32 to 1.50] mm Hg and 1.08 [0.54 to 1.62] mm Hg, respectively, per standard deviation (SD) of BMI). BMI at age 9 was also positively associated with diastolic blood pressure at age 11 (1.16 mmHg per two years [0.49 to 1.84], per SD of BMI). For girls, sedentary time at age 9 years was associated with increased odds of having high systolic blood pressure at age 11 (odds ratio: 1.08 [1.01 to 1.16], per 10 minutes per day). There was no evidence of associations between sedentary time and blood pressure among boys. Similarly, there was little evidence that physical activity was associated with blood pressure in either cross-sectional or prospective analyses. Effective strategies are needed to prevent excess bodyweight among children in order to reduce cardiovascular disease risk