Studies of photoabsorption by atomic hydrogen, oxygen, and nitrogen

Quantitative measurement of atomic photoionization cross sections of atomic hydrogen, oxygen, and nitroge

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

Development of a hybrid multi-scale simulation approach for spray processes

This paper presents a multi-scale approach coupling a Eulerian interface-tracking method and a Lagrangian particle-tracking method to simulate liquid atomisation processes. This method aims to represent the complete spray atomisation process including the primary break-up process and the secondary break-up process, paving the way for high-fidelity simulations of spray atomisation in the dense spray zone and spray combustion in the dilute spray zone. The Eulerian method is based on the coupled level-set and volume-of-fluid method for interface tracking, which can accurately simulate the primary break-up process. For the coupling approach, the Eulerian method describes only large droplet and ligament structures, while small-scale droplet structures are removed from the resolved Eulerian description and transformed into Lagrangian point-source spherical droplets. The Lagrangian method is thus used to track smaller droplets. In this study, two-dimensional simulations of liquid jet atomisation are performed. We analysed Lagrangian droplet formation and motion using the multi-scale approach. The results indicate that the coupling method successfully achieves multi-scale simulations and accurately models droplet motion after the Eulerian–Lagrangian transition. Finally, the reverse Lagrangian–Eulerian transition is also considered to cope with interactions between Eulerian droplets and Lagrangian droplets.This work was supported by the Engineering and Physical Sciences Research Council of the UK (grant number EP/L000199/1)

Are supernova remnants quasi-parallel or quasi-perpendicular accelerators

Observations of shock waves in the solar system which show a pronounced difference in the plasma wave and particle environment depending on whether the shock is propagating along or perpendicular to the interplanetary magnetic field are discussed. Theories for particle acceleration developed for quasi-parallel and quasi-perpendicular shocks, when extended to the interstellar medium suggest that the relativistic electrons in radio supernova remnants are accelerated by either the Q parallel or Q perpendicular mechanisms. A model for the galactic magnetic field and published maps of supernova remnants were used to search for a dependence of structure on the angle Phi. Results show no tendency for the remnants as a whole to favor the relationship expected for either mechanism, although individual sources resemble model remnants of one or the other acceleration process

Smarter choices ?changing the way we travel. Case study reports

This report accompanies the following volume:Cairns S, Sloman L, Newson C, Anable J, Kirkbride A and Goodwin P (2004)Smarter Choices ? Changing the Way We Travel. Report published by theDepartment for Transport, London, available via the ?Sustainable Travel? section ofwww.dft.gov.uk, and from http://eprints.ucl.ac.uk/archive/00001224/

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

Smarter choices - changing the way we travel

Summary: In recent years, there has been growing interest in a range of initiatives, which are now widelydescribed as 'soft' transport policy measures. These seek to give better information and opportunities,aimed at helping people to choose to reduce their car use while enhancing the attractiveness ofalternatives. They are fairly new as part of mainstream transport policy, mostly relativelyuncontroversial, and often popular. They include:. Workplace and school travel plans;. Personalised travel planning, travel awareness campaigns, and public transport information andmarketing;. Car clubs and car sharing schemes;. Teleworking, teleconferencing and home shopping.This report draws on earlier studies of the impact of soft measures, new evidence from the UK andabroad, case study interviews relating to 24 specific initiatives, and the experience of commercial,public and voluntary stakeholders involved in organising such schemes. Each of the soft factors isanalysed separately, followed by an assessment of their combined potential impact.The assessment focuses on two different policy scenarios for the next ten years. The 'high intensity'scenario identifies the potential provided by a significant expansion of activity to a much morewidespread implementation of present good practice, albeit to a realistic level which still recognisesthe constraints of money and other resources, and variation in the suitability and effectiveness of softfactors according to local circumstances. The 'low intensity' scenario is broadly defined as aprojection of the present (2003-4) levels of local and national activity on soft measures.The main features of the high intensity scenario would be. A reduction in peak period urban traffic of about 21% (off-peak 13%);. A reduction of peak period non-urban traffic of about 14% (off-peak 7%);. A nationwide reduction in all traffic of about 11%.These projected changes in traffic levels are quite large (though consistent with other evidence onbehavioural change at the individual level), and would produce substantial reductions in congestion.However, this would tend to attract more car use, by other people, which could offset the impact ofthose who reduce their car use unless there are measures in place to prevent this. Therefore, thoseexperienced in the implementation of soft factors locally usually emphasise that success depends onsome or all of such supportive policies as re-allocation of road capacity and other measures toimprove public transport service levels, parking control, traffic calming, pedestrianisation, cyclenetworks, congestion charging or other traffic restraint, other use of transport prices and fares, speedregulation, or stronger legal enforcement levels. The report also records a number of suggestionsabout local and national policy measures that could facilitate the expansion of soft measures.The effects of the low intensity scenario, in which soft factors are not given increased policy prioritycompared with present practice, are estimated to be considerably less than those of the high intensityscenario, including a reduction in peak period urban traffic of about 5%, and a nationwide reductionin all traffic of 2%-3%. These smaller figures also assume that sufficient other supporting policies areused to prevent induced traffic from eroding the effects, notably at peak periods and in congestedconditions. Without these supportive measures, the effects could be lower, temporary, and perhapsinvisible.Previous advice given by the Department for Transport in relation to multi-modal studies was that softfactors might achieve a nationwide traffic reduction of about 5%. The policy assumptionsunderpinning this advice were similar to those used in our low intensity scenario: our estimate isslightly less, but the difference is probably within the range of error of such projections.The public expenditure cost of achieving reduced car use by soft measures, on average, is estimated atabout 1.5 pence per car kilometre, i.e. £15 for removing each 1000 vehicle kilometres of traffic.Current official practice calculates the benefit of reduced traffic congestion, on average, to be about15p per car kilometre removed, and more than three times this level in congested urban conditions.Thus every £1 spent on well-designed soft measures could bring about £10 of benefit in reducedcongestion alone, more in the most congested conditions, and with further potential gains fromenvironmental improvements and other effects, provided that the tendency of induced traffic to erodesuch benefits is controlled. There are also opportunities for private business expenditure on some softmeasures, which can result in offsetting cost savings.Much of the experience of implementing soft factors is recent, and the evidence is of variable quality.Therefore, there are inevitably uncertainties in the results. With this caveat, the main conclusion isthat, provided they are implemented within a supportive policy context, soft measures can besufficiently effective in facilitating choices to reduce car use, and offer sufficiently good value formoney, that they merit serious consideration for an expanded role in local and national transportstrategy.AcknowledgementsWe gratefully acknowledge the many contributions made by organisations and individuals consultedas part of the research, and by the authors of previous studies and literature reviews which we havecited. Specific acknowledgements are given at the end of each chapter.We have made extensive use of our own previous work including research by Lynn Sloman funded bythe Royal Commission for the Exhibition of 1851 on the traffic impact of soft factors and localtransport schemes (in part previously published as 'Less Traffic Where People Live'); and by SallyCairns and Phil Goodwin as part of the research programme of TSU supported by the Economic andSocial Research Council, and particularly research on school and workplace travel plans funded bythe DfT (and managed by Transport 2000 Trust), on car dependence funded by the RAC Foundation,on travel demand analysis funded by DfT and its predecessors, and on home shopping funded byEUCAR. Case studies to accompany this report are available at: http://eprints.ucl.ac.uk/archive/00001233

Size frequency distribution of the β-amyloid (aβ) deposits in dementia with Lewy bodies with associated Alzheimer’s disease pathology

The objective is to study β-amyloid (Aβ) deposition in dementia with Lewy bodies (DLB) with Alzheimer’s disease (AD) pathology (DLB/AD). The size frequency distributions of the Aβ deposits were studied and fitted by log-normal and power-law models. Patients were ten clinically and pathologically diagnosed DLB/AD cases. Size distributions had a single peak and were positively skewed and similar to those described in AD and Down’s syndrome. Size distributions had smaller means in DLB/AD than in AD. Log-normal and power-law models were fitted to the size distributions of the classic and diffuse deposits, respectively. Size distributions of Aβ deposits were similar in DLB/AD and AD. Size distributions of the diffuse deposits were fitted by a power-law model suggesting that aggregation/disaggregation of Aβ was the predominant factor, whereas the classic deposits were fitted by a log-normal distribution suggesting that surface diffusion was important in the pathogenesis of the classic deposits

Comparative quantitative study of ‘signature’ pathological lesions in the hippocampus and adjacent gyri of 12 neurodegenerative disorders

The hippocampus (HC) and adjacent gyri are implicated in dementia in several neurodegenerative disorders. To compare HC pathology among disorders, densities of ‘signature’ pathological lesions were measured at a standard location in eight brain regions of 12 disorders. Principal components analysis of the data suggested that the disorders could be divided into three groups: (1) Alzheimer’s disease (AD), Down’s syndrome (DS), sporadic Creutzfeldt–Jakob disease, and variant Creutzfeldt–Jakob disease in which either β-amyloid (Aβ) or prion protein deposits were distributed in all sectors of the HC and adjacent gyri, with high densities being recorded in the parahippocampal gyrus and subiculum; (2) Pick’s disease, sporadic frontotemporal lobar degeneration with TDP-43 immunoreactive inclusions, and neuronal intermediate filament inclusion disease in which relatively high densities of neuronal cytoplasmic inclusions were present in the dentate gyrus (DG) granule cells; and (3) Parkinson’s disease dementia, dementia with Lewy bodies, progressive supranuclear palsy, corticobasal degeneration, and multiple system atrophy in which densities of signature lesions were relatively low. Variation in density of signature lesions in DG granule cells and CA1 were the most important sources of neuropathological variation among disorders. Hence, HC and adjacent gyri are differentially affected in dementia reflecting either variation in vulnerability of hippocampal neurons to specific molecular pathologies or in the spread of pathological proteins to the HC. Information regarding the distribution of pathology could ultimately help to explain variations in different cognitive domains, such as memory, observed in various disorders