The Fission Fragment Rocket Engine for Mars Fast Transit

In this paper we discuss the advantages and challenges of utilizing Fission Fragment Rocket Engines (FFREs) to dramatically reduce transit time in space travel, for example, traveling to Mars. We discuss methods to decrease the size and weight of FFREs. These include utilizing metallic deuterides as moderators, driving the engines with electron beam bremsstrahlung, and operating the FFREs as subcritical assemblies, not as nuclear reactors. We discuss these and other new innovations based upon improved materials and technology that may be integrated into a revolutionary nuclear rocket technology.Comment: 10 pages, 2 figures, 2 table

Prospects For A New Light-Nuclei, Fission-Fusion Energy Cycle

Future advanced nuclear rocket propulsion, and the availability of new nuclear power cycle designs, will benefit substantially from the large current investment in alternative nuclear energy that is underway today. We propose a new nuclear cycle which includes the primary fission of lithium-6, followed by secondary fusion of deuterium and tritium, and a secondary fission of lithium-7 by tritium. This cycle does not produce nuclear waste from its nuclear fuel, since all byproducts of these cascade reactions are stable, provided that the triton production during the primary reaction is fully consumed in the secondary reactions. This cycle may, however, activate surrounding technical materials from its neutron flux. This light-element nuclear fuel is readily obtained through the ongoing expansion of the lithium mining industry and electric vehicle (EV) battery recycling industries.Comment: 10 pages, 2 figure

Estimating the health impact of air pollution in Scotland, and the resulting benefits of reducing concentrations in city centres

Air pollution continues to be a key health issue in Scotland, despite recent improvements in concentrations. The Scottish Government published the Cleaner Air For Scotland strategy in 2015, and will introduce Low Emission Zones (LEZs) in the four major cities (Aberdeen, Dundee, Edinburgh and Glasgow) by 2020. However, there is no epidemiological evidence quantifying the current health impact of air pollution in Scotland, which this paper addresses. Additionally, we estimate the health benefits of reducing concentrations in city centres where most LEZs are located. We focus on cardio-respiratory disease and total non-accidental mortality outcomes, linking them to concentrations of both particulate (PM10 and PM2.5) and gaseous (NO2 and NOx) pollutants. Our two main findings are that: (i) all pollutants exhibit significant associations with respiratory disease but not cardiovascular disease; and (ii) reducing concentrations in city centres with low resident populations only provides a small health benefit

Impact of socioeconomic differences on distributional cost-effectiveness analysis

Public health decision makers value interventions for their effects on overall health and health inequality. Distributional cost-effectiveness analysis (DCEA) incorporates health inequality concerns into economic evaluation by accounting for how parameters, such as effectiveness, differ across population groups. A good understanding of how and when accounting for socioeconomic differences between groups affects the assessment of intervention impacts on overall health and health inequality could inform decision makers where DCEA would add most value. We interrogated 2 DCEA models of smoking and alcohol policies using first national level and then local authority level information on various socioeconomic differences in health and intervention use. Through a series of scenario analyses, we explored the impact of altering these differences on the DCEA results. When all available evidence on socioeconomic differences was incorporated, provision of a smoking cessation service was estimated to increase overall health and increase health inequality, while the screening and brief intervention for alcohol misuse was estimated to increase overall health and reduce inequality. Ignoring all or some socioeconomic differences resulted in minimal change to the estimated impact on overall health in both models; however, there were larger effects on the estimated impact on health inequality. Across the models, there were no clear patterns in how the extent and direction of socioeconomic differences in the inputs translated into the estimated impact on health inequality. Modifying use or coverage of either intervention so that each population group matched the highest level improved the impacts to a greater degree than modifying intervention effectiveness. When local level socioeconomic differences were considered, the magnitude of the impacts was altered; in some cases, the direction of impact on inequality was also altered

Screening for anxiety, depression and suicidality by epilepsy specialists in adult services in Scotland

OBJECTIVE: Clinical guidelines recommend screening people with epilepsy (PWE) regularly for mental distress, but it is unclear how guidelines are implemented. We surveyed epilepsy specialists in adult Scottish services to determine approaches used to screen for anxiety, depression, and suicidality; the perceived difficulty of screening; factors associated with intention to screen; and treatment decisions made following positive screens.METHODS: An anonymous email-based questionnaire survey of epilepsy nurses and epilepsy neurology specialists (n = 38) was conducted.RESULTS: Two in every three specialists used a systematic screening approach; a third did not. Clinical interview was employed more often than standardized questionnaire. Clinicians reported positive attitudes towards screening but found screening difficult to implement. Intention to screen was associated with favorable attitude, perceived control, and social norm. Pharmacological and non-pharmacological interventions were proposed equally often for those screening positive for anxiety or depression.CONCLUSION: Routine screening for mental distress is carried out in Scottish epilepsy treatment settings but is not universal. Attention should be paid to clinician factors associated with screening, such as intention to screen and resulting treatment decisions. These factors are potentially modifiable, offering a means of closing the gap between guideline recommendations and clinical practice.</p

Future declines of Coronary Heart Disease mortality in England and Wales could counter the burden of population ageing

BACKGROUND:Coronary Heart Disease (CHD) remains a major cause of mortality in the United Kingdom. Yet predictions of future CHD mortality are potentially problematic due to population ageing and increase in obesity and diabetes. Here we explore future projections of CHD mortality in England & Wales under two contrasting future trend assumptions. METHODS:In scenario A, we used the conventional counterfactual scenario that the last-observed CHD mortality rates from 2011 would persist unchanged to 2030. The future number of deaths was calculated by applying those rates to the 2012-2030 population estimates. In scenario B, we assumed that the recent falling trend in CHD mortality rates would continue. Using Lee-Carter and Bayesian Age Period Cohort (BAPC) models, we projected the linear trends up to 2030. We validate our methods using past data to predict mortality from 2002-2011. Then, we computed the error between observed and projected values. RESULTS:In scenario A, assuming that 2011 mortality rates stayed constant by 2030, the number of CHD deaths would increase 62% or approximately 39,600 additional deaths. In scenario B, assuming recent declines continued, the BAPC model (the model with lowest error) suggests the number of deaths will decrease by 56%, representing approximately 36,200 fewer deaths by 2030. CONCLUSIONS:The decline in CHD mortality has been reasonably continuous since 1979, and there is little reason to believe it will soon halt. The commonly used assumption that mortality will remain constant from 2011 therefore appears slightly dubious. By contrast, using the BAPC model and assuming continuing mortality falls offers a more plausible prediction of future trends. Thus, despite population ageing, the number of CHD deaths might halve again between 2011 and 2030. This has implications for how the potential benefits of future cardiovascular strategies might best be calculated and presented

Rank-related contrasts in longevity arise from extra-group excursions not delayed senescence in a cooperative mammal

In many cooperatively breeding animal societies, breeders outlive non-breeding subordinates, despite investing heavily in reproduction [1-3]. In eusocial insects, the extended lifespans of breeders arise from specialized slowed aging profiles [1], prompting suggestions that reproduction and dominance similarly defer aging in cooperatively breeding vertebrates, too [4-6]. Although lacking the permanent castes of eusocial insects, breeders of vertebrate societies could delay aging via phenotypic plasticity (similar rank-related changes occur in growth, neuroendocrinology, and behavior [7-10]), and such plastic deferment of aging may reveal novel targets for preventing aging-related diseases [11]. Here, we investigate whether breeding dominants exhibit extended longevity and delayed age-related physiological declines in wild cooperatively breeding meerkats. We show that dominants outlive subordinates but exhibit faster telomere attrition (a marker of cellular senescence and hallmark of aging [12]) and that in dominants (but not subordinates), rapid telomere attrition is associated with mortality. Our findings further suggest that, rather than resulting from specialized aging profiles, differences in longevity between dominants and subordinates are driven by subordinate dispersal forays, which become exponentially more frequent with age and increase subordinate mortality. These results highlight the need to critically examine the causes of rank-related longevity contrasts in other cooperatively breeding vertebrates, including social mole-rats, where they are currently attributed to specialized aging profiles in dominants [4]

Furthering the understanding of silicate-substitution in α-tricalcium phosphate : an X-ray diffraction, X-ray fluorescence and solid-state nuclear magnetic resonance study

High-purity (SupT) and reagent-grade (ST), stoichiometric and silicate-containing α-tricalcium phosphate (α-TCP: ST0/SupT0 and Si-TCP x = 0.10: ST10/SupT10) were prepared by solid-state reaction based on the substitution mechanism Ca3(PO4)(2-x)(SiO4)x. Samples were determined to be phase pure by X-ray diffraction (XRD), and Rietveld analysis performed on the XRD data confirmed inclusion of Si in the α-TCP structure as determined by increases in unit cell parameters; particularly marked increases in the b-axis and β-angle were observed. X-ray fluorescence (XRF) confirmed the presence of expected levels of Si in Si-TCP compositions as well as significant levels of impurities (Mg, Al and Fe) present in all ST samples; SupT samples showed both expected levels of Si and a high degree of purity. Phosphorus (31P) magic-angle-spinning solid-state nuclear magnetic resonance (MAS NMR) measurements revealed that the high-purity reagents used in the synthesis of SupT0 can resolve the 12 expected peaks in the 31P spectrum of α-TCP compared to the low-purity ST0 that showed significant spectral line broadening; line broadening was also observed with the inclusion of Si which is indicative of induced structural disorder. Silicon (29Si) MAS NMR was also performed on both Si-TCP samples which revealed Q0 species of Si with additional Si Q1/Q2 species that may indicate a potential charge-balancing mechanism involving the inclusion of disilicate groups; additional Q4 Si species were also observed, but only for ST10. Heating and cooling rates were briefly investigated by 31P MAS NMR which showed no significant line broadening other than that associated with the emergence of β-TCP which was only realised with the reagent-grade sample ST0. This study provides an insight into the structural effects of Si-substitution in α-TCP and could provide a basis for understanding how substitution affects the physicochemical properties of the material