Half-life of cost-of-illness estimates: the case of Spina Bifida

ManuscriptNeural tube defects, which include spina bifida, are one of the most frequent and important categories of birth defects. Accordingly, there has been considerable interest in studying the impact of spina bifida as a public health problem. This impact can be measured in various ways, including disease-specific mortality, morbidity, functional limitation or disability, and quality of life impairment. Each of these measures captures one component of the total burden of disease. Such measures of impact are important because they allow public health agencies, researchers, and health care providers to understand the effects of preventive or diagnostic interventions, changes in disease incidence or prevalence, and new technologies

Demonstration of fast-acting protection as a key enabler for more-electric aircraft interconnected architetctures

Driven by anticipated fuel-burn and efficiency benefits, the more-electric aircraft (MEA) concept is a technological shift in the aviation industry, which seeks to replace mechanical, hydraulic and pneumatic functions with electrical equivalents. This shift has greatly increased the electrical power demands of aircraft and has made MEA networks larger and more complex. Consequently, new and more efficient electrical architectures are required, with interconnected generation potentially being one design approach that could bring improved performance and fuel savings. This study discusses the current state of interconnected generation in the aviation industry and key technological advances that could facilitate feasible interconnection options. This study demonstrates that interconnected systems can breach certification rules under fault conditions. Through modelling and simulation, it investigates the airworthiness-requirements compliance of potential impedance solutions to this issue and quantifies the potential impact on system weight. It concludes by identifying fast fault clearing protection as being a key enabling technology that facilitates the use of light-weight and standards-compliant architectures

Establishing viable fault management strategies for distributed electrical propulsion aircraft

Electrical propulsion has the potential to increase aircraft performance. However, this will require the design and development of an appropriate aircraft electrical system to power the propulsor motors. In order to protect this system against electrical faults, which have the potential to threaten the safety of the aircraft, a robust fault management strategy (FMS) is required. The FMS will comprise aspects of system design such as redundancy, reliability and reconfiguration and will rely on a range of protection devices deployed on the electrical system to intercept and manage faults. The electrical architecture will be shaped by the FMS as this will determine the optimal configuration to enable security of supply. The protection system is integral to the system design. Hence it must to be considered from the outset, as part of the wider aircraft concept development. This paper presents a robust framework to develop the optimal FMS for an electrical propulsion aircraft, which is subject to all the relevant aircraft constraints and incorporates the available protection devices for a chosen aircraft for a given developmental timeframe. A case study is then presented in which this protection design methodology is applied to the NASA STARC-ABL aircraft concept in order to demonstrate that the available protection for an electrical propulsion aircraft defines the possible electrical architectures

Daily patterns of fluorescence in vivo in the central equatorial Pacific

A daily cycle of fluorescence in vivo was strikingly apparent in surface waters of the central equatorial Pacific between latitudes 4N and 10S, but not in waters to the north or south of this zone. These changes in fluorescence did not represent changes in chlorophyll-a concentration, but rather a photoinhibition of fluorescence by ambient light. Higher nutrient and chlorophyll-a concentrations were found in the region where cycling occurred...

MEN 2A: Update on the Northern Ireland and Australian Family

The Northern Ireland/Australian family with multiple endocrine neoplasia type 2A (MEN 2A) originally described in 1987 is presented with a revised and enlarged pedigree. Four members of the first generation studied have died. A seventh member of the second generation studied has developed medullary thyroid carcinoma and has progressed to surgery. None of the third generation members studied has shown any conclusive abnormality in metabolic screening tests. Each member of the third and fourth generations has had genetic counseling and (if appropriate) DNA analysis with gene probes close to the MEN 2A gene locus on chromosome 10. All members of this highly penetrant family have remained asymptomatic for their disease

Hybrid electric aircraft : state of the art and key electrical system challenges

In both Europe and the USA, the aerospace sector is actively pursuing revolutionary design concepts to further improve the environmental impact of air travel. This is partly a result of increasing pressure on the industry from government and other organisations to reduce emissions , despite the continuing increase in air traffic [1] . The aggressive targets set by NASA and the EU [1, 2, 3] (e.g. the Advisory Coun cil for Aviation Research and Innovation in Europe has a target of a 75% reduction in CO2 emissions and a 90% reduction of NOx emissions by 2050) cannot be achieved through marginal improvements in turbine technology or aircraft design. Rather, disruptive technologies and more innovative aircraft must be considered

The anatomy of friendship:neuroanatomic homophily of the social brain among classroom friends

Homophily refers to the tendency to like similar others. Here, we ask if homophily extends to brain structure. Specifically: do children who like one another have more similar brain structures? We hypothesized that neuroanatomic similarity tied to friendship is most likely to pertain to brain regions that support social cognition. To test this hypothesis, we analyzed friendship network data from 1186 children in 49 classrooms. Within each classroom, we identified “friendship distance”—mutual friends, friends-of-friends, and more distantly connected or unconnected children. In total, 125 children (mean age = 7.57 years, 65 females) also had good quality neuroanatomic magnetic resonance imaging scans from which we extracted properties of the “social brain.” We found that similarity of the social brain varied by friendship distance: mutual friends showed greater similarity in social brain networks compared with friends-of-friends (β = 0.65, t = 2.03, P = 0.045) and even more remotely connected peers (β = 0.77, t = 2.83, P = 0.006); friends-of-friends did not differ from more distantly connected peers (β = −0.13, t = −0.53, P = 0.6). We report that mutual friends have similar “social brain” networks, adding a neuroanatomic dimension to the adage that “birds of a feather flock together.

Comparison of candidate architectures for future distributed propulsion aircraft

Turbine engine driven distributed electrical aircraft power systems (also referred to as Turboelectric Distributed Propulsion (TeDP)) are proposed for providing thrust for future aircraft with superconducting components operating at 77K in order for performance and emissions targets to be met. The proposal of such systems presents a radical change from current state-of-the-art aero-electrical power systems. Central to the development of such power systems are architecture design trades which must consider system functionality and performance, system robustness and fault ride-through capability, in addition to the balance between mass and efficiency. This paper presents a quantitative comparison of the three potential candidate architectures for TeDP electrical networks. This analysis provides the foundations for establishing the feasibility of these different architectures subject to design and operational constraints. The findings of this paper conclude that a purely AC synchronous network performs best in terms of mass and efficiency, but similar levels of functionality and controllability to an architecture with electrical decoupling via DC cannot readily be achieved. If power electronic converters with cryocoolers are found to be necessary for functionality and controllability purposes, then studies show that a significant increase in the efficiency of solid state switching components is necessary to achieve specified aircraft performance targets

Maternal obesity has little effect on the immediate offspring but impacts on the next generation

Maternal obesity during pregnancy has been linked to an increased risk of obesity and cardiometabolic disease in the offspring, a phenomenon attributed to developmental programming. Programming effects may be transmissible across generations through both maternal and paternal inheritance, although the mechanisms remain unclear. Using a mouse model, we explored the effects of moderate maternal diet-induced obesity (DIO) on weight gain and glucose-insulin homeostasis in first-generation (F1) and second-generation offspring. DIO was associated with insulin resistance, hyperglycemia and dyslipidemia before pregnancy. Birth weight was reduced in female offspring of DIO mothers (by 6%, P = .039), and DIO offspring were heavier than controls at weaning (males by 47%, females by 27%), however there were no differences in glucose tolerance, plasma lipids, or hepatic gene expression at 6 months. Despite the relative lack of effects in the F1, we found clear fetal growth restriction and persistent metabolic changes in otherwise unmanipulated second-generation offspring with effects on birth weight, insulin levels, and hepatic gene expression that were transmitted through both maternal and paternal lines. This suggests that the consequences of the current dietary obesity epidemic may also have an impact on the descendants of obese individuals, even when the phenotype of the F1 appears largely unaffected