Pack Density Limitations of Hybrid Parachutes

The development and testing of the Orion crew capsule parachute system has provided a unique opportunity to study dense parachute packing techniques and limits, in order to establish a new baseline for future programs. The density of parachute packs has a significant influence on vibration loads, retention system stresses, and parachute mortar performance. Material compositions and pack densities of existing designs for space capsule recovery were compared, using the pack density of the Apollo main parachutes as the current baseline. The composition of parachutes has changed since Apollo, incorporating new materials such as Kevlar , Vectran , Teflon and Spectra . These materials have different specific densities than Nylon, so the densities of hybrid parachute packs cannot be directly compared to Nylon parachutes for determination of feasibility or volume allocation. Six parachute packs were evaluated in terms of weighted average solid density in order to achieve a non-dimensional comparison of packing density. Means of mitigating damage due to packing pressure and mortar firing were examined in light of the Capsule Parachute Assembly System (CPAS) and Apollo experience. Parachute design improvements including incorporation of modern materials and manufacturing processes serves to make CPAS the new knowledge base on which future spacecraft parachute systems will be built

The photometric determination of nitrate in sea water with a strychnidine reagent

The routine determination of small concentrations of nitrate in water containing considerable chloride ion is limited to a few special procedures. Indirect reductive methods are usually avoided since natural waters contain other nitrogeneous substances. Direct estimations have been restricted to a few colorimetric procedures

A Moving-Knife Solution to the Four-Person Envy-Free Cake-Division Problem

Envy-freeness

Bending the Medicare Cost Curve in 12 Months or Less: How Preventative Health Care can Yield Significant Near-Term Savings for Acute Care in Alberta

Over the course of more than 30 years, a series of Canadian government commissions and health policy researchers have repeatedly identified the importance of “bending the cost curve” to sustain publicly funded health care, and the potential to do so through upstream investment in health promotion and disease prevention. So far, however, the level of public investment in prevention represents only a slight portion of total public health care expenditure, largely consisting of traditional public health initiatives such as vaccinations, disease screening and information campaigns. This study of the Pure North S’Energy Foundation’s preventative health care program — wherein health care usage by program participants was measured against age- and sex-matched control samples — finds that the sort of preventative health care services offered by Pure North can lead to genuine and significant near-term cost savings for Canada’s single-payer health care system. Participants in the first year of the program required 25 per cent fewer hospital visits and 17 per cent fewer emergency room visits compared to the control group. Among those who persisted in the program for a year or longer, the effects were even more significant: 45 per cent fewer hospital visits in the year after joining, and 28 per cent fewer visits to emergency departments, compared to the control group. This represents real cost savings for a public health service: From $388 per person who joined the program to$677 per person who persisted beyond the first year. As a proportion of annual health spending for these participants on hospitals, emergency departments and general practitioners, this represents a cost reduction ranging from 22 to 39 per cent. If the Alberta government were able to implement this kind of program provincewide (at an estimated cost of $500 per participant), and were to realize similar results in terms of reduced strain on acute care services, it is possible that the province could free-up the equivalent of 1,632 hospital beds every year. That is roughly the same as building two entirely new hospitals each on the scale of Calgary’s Foothills Medical Centre. This demonstrates that “bending the cost curve” for public health care spending is not merely something that is realizable in the long term, but rather in the immediate future, as quickly as within a year after this kind of program could be implemented province-wide. And yet, the near-term savings in acute care services represent only the first wave of benefits. The prevalence of chronic diseases and conditions, including diabetes, heart disease, cancer and mental illness, have been rising and are projected to keep doing so over the coming decade. The Pure North program aims to prevent and address these health conditions and chronic diseases through a combination of screening and testing, lifestyle modification, nutrition education, the identification of nutritional deficiencies, and dietary supplements. The long-term benefits of a Pure North-style program implemented province-wide in Alberta are likely to be that much greater as the prevalence of diabetes, heart disease, cancer and mental illness is tempered through the use of widespread preventative care. Then there are the broader “indirect benefits” of a generally healthier population: higher labour productivity, higher incomes and greater well-being. These returns to the Alberta government, and taxpayer, have the potential to be as large, if not larger, than the direct benefits of significantly reduced acute care costs

The Importance of Body Weight for the Dose Response Relationship of Oral Vitamin D Supplementation and Serum 25-Hydroxyvitamin D in Healthy Volunteers

Unlike vitamin D recommendations by the Institute of Medicine, the Clinical Practice Guidelines by the Endocrine Society acknowledge body weight differentials and recommend obese subjects be given two to three times more vitamin D to satisfy their body's vitamin D requirement. However, the Endocrine Society also acknowledges that there are no good studies that clearly justify this. In this study we examined the combined effect of vitamin D supplementation and body weight on serum 25-hydroxyvitamin (25(OH)D) and serum calcium in healthy volunteers. We analyzed 22,214 recordings of vitamin D supplement use and serum 25(OH)D from 17,614 healthy adult volunteers participating in a preventive health program. This program encourages the use of vitamin D supplementation and monitors its use and serum 25(OH)D and serum calcium levels. Participants reported vitamin D supplementation ranging from 0 to 55,000 IU per day and had serum 25(OH)D levels ranging from 10.1 to 394 nmol/L. The dose response relationship between vitamin D supplementation and serum 25(OH)D followed an exponential curve. On average, serum 25(OH)D increased by 12.0 nmol/L per 1,000 IU in the supplementation interval of 0 to 1,000 IU per day and by 1.1 nmol/L per 1,000 IU in the supplementation interval of 15,000 to 20,000 IU per day. BMI, relative to absolute body weight, was found to be the better determinant of 25(OH)D. Relative to normal weight subjects, obese and overweight participants had serum 25(OH)D that were on average 19.8 nmol/L and 8.0 nmol/L lower, respectively (P<0.001). We did not observe any increase in the risk for hypercalcemia with increasing vitamin D supplementation. We recommend vitamin D supplementation be 2 to 3 times higher for obese subjects and 1.5 times higher for overweight subjects relative to normal weight subjects. This observational study provides body weight specific recommendations to achieve 25(OH)D targets

Tract-Based Spatial Statistics in Preterm-Born Neonates Predicts Cognitive and Motor Outcomes at 18 Months.

BACKGROUND AND PURPOSE: Adverse neurodevelopmental outcome is common in children born preterm. Early sensitive predictors of neurodevelopmental outcome such as MR imaging are needed. Tract-based spatial statistics, a diffusion MR imaging analysis method, performed at term-equivalent age (40 weeks) is a promising predictor of neurodevelopmental outcomes in children born very preterm. We sought to determine the association of tract-based spatial statistics findings before term-equivalent age with neurodevelopmental outcome at 18-months corrected age. MATERIALS AND METHODS: Of 180 neonates (born at 24-32-weeks\u27 gestation) enrolled, 153 had DTI acquired early at 32 weeks\u27 postmenstrual age and 105 had DTI acquired later at 39.6 weeks\u27 postmenstrual age. Voxelwise statistics were calculated by performing tract-based spatial statistics on DTI that was aligned to age-appropriate templates. At 18-month corrected age, 166 neonates underwent neurodevelopmental assessment by using the Bayley Scales of Infant Development, 3rd ed, and the Peabody Developmental Motor Scales, 2nd ed. RESULTS: Tract-based spatial statistics analysis applied to early-acquired scans (postmenstrual age of 30-33 weeks) indicated a limited significant positive association between motor skills and axial diffusivity and radial diffusivity values in the corpus callosum, internal and external/extreme capsules, and midbrain (P \u3c .05, corrected). In contrast, for term scans (postmenstrual age of 37-41 weeks), tract-based spatial statistics analysis showed a significant relationship between both motor and cognitive scores with fractional anisotropy in the corpus callosum and corticospinal tracts (P \u3c .05, corrected). Tract-based spatial statistics in a limited subset of neonates (n = 22) scanned at CONCLUSIONS: The strength of the association between fractional anisotropy values and neurodevelopmental outcome scores increased from early-to-late-acquired scans in preterm-born neonates, consistent with brain dysmaturation in this population

Laying the Foundation for Policy: Measuring Local Prevalence for Autism Spectrum Disorder

Claims have been made that families with children living with autism spectrum disorders (ASD) have been migrating to Alberta because of higher funding available for ASD supports compared to other provinces. The legitimacy of these claims, along with many others about the adequacy or inadequacy of funding for supporting persons living with ASD, has not been evaluated because we simply don’t know how many people in Alberta are living with ASD. Typically in Canada, ASD prevalence is reported in national figures, based on international estimates. Canadian prevalence estimates for ASD are needed. With no national surveillance system in place, national estimates are difficult to determine. In addition, such broad measurements are problematic as they may not adequately inform the service delivery needs for specific jurisdictions. A new study shows that 1,711, or 1 in 94, school age children in the Calgary region have an ASD diagnosis. As this number matches what is often reported for the national prevalence of ASD, it suggests that Alberta’s relatively higher ASD funding is not inducing in-migration of families seeking better support. The data also show that the prevalence is higher in elementary-grade children, with a diagnosis in one of every 86 children. In the senior grades, there are significantly fewer students with ASD diagnoses, specifically within the Calgary Board of Education. There is no evident reason for diagnoses to seemingly dematerialize in the older grades. These students could be dropping out or choosing home-schooling in greater numbers. Possibly there has been an increase in prevalence. These prevalence estimates help to inform the demand for special-needs services within the local school system. In addition, there is growing concern that upon graduation there is a “support cliff” resulting from a less systematized, less generous support system available for adults with neurodevelopmental disability. Families that need support for ASD face enough challenges; it is critical for policy-makers to be aware of the extent of the situation in their own jurisdiction so as to develop the right kinds of supports for these families