6,973 research outputs found
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A Simple Approach to Project Extreme Old Age Mortality Rates and Value Mortality-Related Financial Instruments
This article shows how mortality models that involve age effects can be fitted to ages beyond the sample range using projections of age effects as replacements for age effects that might not be in the sample. This ‘projected age effect’ approach allows insurers to use age-effect mortality models to obtain valuations of financial instruments such as annuities that depend on projections of extreme old ag
Analysis of secondary cells with lithium anodes and immobilized fused-salt electrolytes
Secondary cells with liquid lithium anodes, liquid bismuth or tellurium cathodes, and fused lithium halide electrolytes immobilized as rigid pastes operate between 380 and 485 degrees. Applications include power sources in space, military vehicle propulsion and special commercial vehicle propulsion
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The Impact of Covid-19 on Future Higher-Age Mortality
Covid-19 has predominantly affected mortality at high ages. It kills by inflaming and clogging the air sacs in the lungs, depriving the body of oxygen ‒ inducing hypoxia ‒ which closes down essential organs, in particular the heart, kidneys and liver, and causes blood clots (which can lead to stroke or pulmonary embolism) and neurological malfunction.
Evidence from different countries points to the fact that people who die from Covid-19 are often, but not always, much less healthy than the average for their age group. This is true for England & Wales – the two countries we focus on in this study. The implication is that the years of life lost through early death are less than the average for each age group, with how much less being a source of considerable debate. We argue that many of those who die from coronavirus would have died anyway in the relatively near future due to their existing frailties or co-morbidities. We demonstrate how to capture this link to poorer-than-average health using a model in which individual deaths are ‘accelerated’ ahead of schedule due to Covid-19. The model structure and its parameterization build on the observation that Covid-19 mortality by age is approximately proportional to all-cause mortality. This, in combination with current predictions of total deaths, results in the important conclusion that, everything else being equal, the impact of Covid-19 on the mortality rates of the surviving population will be very modest. Specifically, the degree of anti-selection is likely to be very small, since the life expectancy of survivors does not increase by a significant amount over pre-pandemic levels.
We also analyze the degree to which Covid-19 mortality varies with socio-economic status. Headline statistics suggest that the most deprived groups have been disproportionately affected by Covid-19. However, once we control for regional differences in mortality rates, Covid-19 deaths in both the most and least deprived groups are also proportional to the all-cause mortality of these groups. However, the groups in between have approximately 10-15% lower Covid-19 deaths compared with their all-cause mortality.
We argue that useful lessons about the potential pattern of accelerated deaths from Covid-19 can be drawn from examining deaths from respiratory diseases, especially at different age ranges. We also argue that it is possible to draw useful lessons about volatility spikes in Covid-19 deaths from examining past seasonal flu epidemics. However, there is an important difference. Whereas the spikes in seasonal flu increase with age, our finding that Covid-19 death rates are approximately proportional to all-cause mortality suggests that any spike in Covid-19 mortality in percentage terms would be similar across all age ranges.
Finally, we discuss some of the indirect consequences for future mortality of the pandemic and the ‘lockdown’ measures governments have imposed to contain it. For example, there is evidence that some surviving patients at all ages who needed intensive care could end up with a new impairment, such as organ damage, which will reduce their life expectancy. There is also evidence that many people in lockdown did not seek a timely medical assessment for a potential new illness, such as cancer, or deferred seeking treatment for an existing serious illness, with the consequence that non-Covid-19-related mortality rates could increase in future. Self-isolation during lockdown has contributed to an increase in alcohol and drug consumption by some people which might, in turn, reduce their life expectancy. If another consequence of the pandemic is a recession and/or an acceleration in job automation, resulting in long-term unemployment, then this could lead to so-called ‘deaths of despair’ in future. Other people, by contrast, might permanently change their social behaviour or seek treatments that delay the impact or onset of age-related diseases, one of the primary factors that make people more susceptible to the virus – both of which could have the effect of increasing their life expectancy. It is, however, too early to quantify these possibilities, although it is conceivable that these indirect consequences could have a bigger impact on future average life expectancy than the direct consequences measured by the accelerated deaths model
Lapped joints of bars in bundles
The approach of European and North American Design Code rules for design of lapped joints of reinforcing bars within a bundle differ markedly, with the former permitting the same or shorter laps with respect to laps of individual bars, while the other requires longer laps. This paper reports an experimental in- vestigation to evaluate performance of lapped joints in which individual reinforcing bars within a bundle of two or three bars are lapped. The results show that it is not necessary to increase lap lengths of individual bars within a bundle, and that failure is less brittle where lap joints confined by links are staggered longitudinally, whether the lap is between individual bars or is of one bar in a pair or bundle. The outcome does, however, question the validity of the reductions permitted in EC2 for staggering laps, and suggests that it would be prudent to suspend use of the α6 reduction factor for proportion of bars lapped at a section pending more tho- rough investigatio
Improving the usability of the hierarchical file system
Whether you are interested in improving the usability of Linux, Macintosh or Windows, there is one restriction you cannot escape - the hierarchical file storage system. The notion of files and folders has been with us for so long that it almost seems axiomatic. In this paper we look at the effects on users of forcing a hierarchical classification of files. We also consider how some of the resultant problems can be tackled with a new piece of file browsing software based on the ideas of relational database systems
Simultaneous multi-frequency single-pulse properties of AXP XTE J1810-197
We have used the 76-m Lovell, 94-m equivalent WSRT and 100-m Effelsberg radio
telescopes to investigate the simultaneous single-pulse properties of the radio
emitting magnetar AXP XTE J1810-197 at frequencies of 1.4, 4.8 and 8.35 GHz
during May and July 2006. We study the magnetar's pulse-energy distributions
which are found to be very peculiar as they are changing on time-scales of days
and cannot be fit by a single statistical model. The magnetar exhibits strong
spiky single giant-pulse-like subpulses, but they do not fit the definition of
the giant pulse or giant micropulse phenomena. Measurements of the
longitude-resolved modulation index reveal a high degree of intensity
fluctuations on day-to-day time-scales and dramatic changes across pulse phase.
We find the frequency evolution of the modulation index values differs
significantly from what is observed in normal radio pulsars. We find that no
regular drifting subpulse phenomenon is present at any of the observed
frequencies at any observing epoch. However, we find a quasi-periodicity of the
subpulses present in the majority of the observing sessions. A correlation
analysis indicates a relationship between components from different
frequencies. We discuss the results of our analysis in light of the emission
properties of normal radio pulsars and a recently proposed model which takes
radio emission from magnetars into consideration.Comment: 15 pages, 11 figures, accepted for publication by MNRA
Using ambulatory care sensitive hospitalisations to analyse the effectiveness of primary care services in Mexico.
Ambulatory care sensitive hospitalisations (ACSH) have been widely used to study the quality and effectiveness of primary care. Using data from 248 general hospitals in Mexico during 2001-2011 we identify 926,769 ACSHs in 188 health jurisdictions before and during the health insurance expansion that took place in this period, and estimate a fixed effects model to explain the association of the jurisdiction ACSH rate with patient and community factors. National ACSH rate increased by 50%, but trends and magnitude varied at the jurisdiction and state level. We find strong associations of the ACSH rate with socioeconomic conditions, health care supply and health insurance coverage even after controlling for potential endogeneity in the rolling out of the insurance programme. We argue that the traditional focus on the increase/decrease of the ACSH rate might not be a valid indicator to assess the effectiveness of primary care in a health insurance expansion setting, but that the ACSH rate is useful when compared between and within states once the variation in insurance coverage is taken into account as it allows the identification of differences in the provision of primary care. The high heterogeneity found in the ACSH rates suggests important state and jurisdiction differences in the quality and effectiveness of primary care in Mexico
The European preexposure prophylaxis revolution
PURPOSE OF REVIEW: The review describes the European epidemic and the challenges in moving from clinical trials of preexposure prophylaxis (PrEP) to routine practice. RECENT FINDINGS: Two European trials conducted in gay and other MSM and transgender women reported a high and consistent reduction in HIV incidence using oral PrEP with tenofovir/emtricitabine (TDF/FTC). The incidence of HIV infection in the control group was much higher than anticipated, based on routine surveillance data in MSM, in spite of the highest standard of HIV prevention available. SUMMARY: Recent results have highlighted the urgent need to make PrEP available to key populations in Europe as an additional prevention tool. Gilead has not yet submitted an application to use TDF/FTC as PrEP in Europe. Although regulatory approval would accelerate implementation, countries are already dispensing TDF/FTC as postexposure prophylaxis without this. Services for prevention are diverse across countries ranging from free, walk-in services for the diagnosis and treatment of HIV and other sexually transmitted infections, to insurance-dependent reimbursement of private clinical services. Momentum is gathering in Europe with PrEP demonstration projects in MSM and a growing demand from community organizations. Each Member State urgently needs to identify their key populations and determine the service best placed to provide this new prevention strategy within a comprehensive prevention package
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