Performance of high-altitude, long-endurance, turboprop airplanes using conventional or cryogenic fuels

An analytical study has been conducted to evaluate the potential endurance of remotely piloted, low speed, high altitude, long endurance airplanes designed with 1990 technology. The baseline configuration was a propeller driven, sailplane like airplane powered by turbine engines that used JP-7, liquid methane, or liquid hydrogen as fuel. Endurance was measured as the time spent between 60,000 feet and an engine limited maximum altitude of 70,000 feet. Performance was calculated for a baseline vehicle and for configurations derived by varying aerodynamic, structural or propulsion parameters. Endurance is maximized by reducing wing loading and engine size. The level of maximum endurance for a given wing loading is virtually the same for all three fuels. Constraints due to winds aloft and propulsion system scaling produce maximum endurance values of 71 hours for JP-7 fuel, 70 hours for liquid methane, and 65 hours for liquid hydrogen. Endurance is shown to be strongly effected by structural weight fraction, specific fuel consumption, and fuel load. Listings of the computer program used in this study and sample cases are included in the report

Turbid water measurements of remote sensing penetration depth at visible and near-infrared wavelength

Remote sensing of water quality is dicussed. Remote sensing penetration depth is a function both of water type and wavelength. Results of three tests to help demonstrate the magnitude of this dependence are presented. The water depth to which the remote-sensor data was valid was always less than that of the Secchi disk depth, although not always the same fraction of that depth. The penetration depths were wavelength dependent and showed the greatest variation for the water type with largest Secchi depth. The presence of a reflective plate, simulating a reflective subsurface, increased the apparent depth of light penetration from that calculated for water of infinite depth

Monetary costs of agitation in older adults with Alzheimer's disease in the UK: prospective cohort study

While nearly half of all people with Alzheimer's disease (AD) have agitation symptoms every month, little is known about the costs of agitation in AD. We calculated the monetary costs associated with agitation in older adults with AD in the UK from a National Health Service and personal social services perspective

Associations between health and different types of environmental incivility : a Scotland-wide study

Objectives: Concern about the impact of the environment on health and well being has tended to focuson the physical effects of exposure to toxic and infectious substances, and on the impact of large scale infrastructures. Less attention has been paid to the possible psychosocial consequences of people's subjective perceptions of their everyday, street level environment, such as the incidence of litter and graffiti. As little is known about the potential relative importance for health of perceptions of different types of environmental incivility, a module was developed for inclusion in the 2004 Scottish Social Attitudes survey in order to investigate this relationship. Study design: A random sample of 1637 adults living across a range of neighbourhoods throughout Scotland was interviewed. Methods: Respondents were asked to rate their local area on a range of possible environmental incivilities. These incivilities were subsequently grouped into three domains: (i) street level incivilities (e.g. litter, graffiti); (ii) large scale infrastructural incivilities (e.g. telephone masts); and (iii) the absence of environmental goods (e.g. safe play areas for children). For each of the three domains, the authors examined the degree to which they were thought to pose a problem locally, and how far these perceptions varied between those living in deprived areas and those living in less deprived areas. Subsequently, the relationships between these perceptions and self assessed health and health behaviours were explored, after controlling for gender, age and social class. Results: Respondents with the highest levels of perceived street level incivilities were almost twice aslikely as those who perceived the lowest levels of street level incivilities to report frequent feelings of anxiety and depression. Perceived absence of environmental goods was associated with increased anxiety (2.5 times more likely) and depression (90% more likely), and a 50% increased likelihood of being a smoker. Few associations with health were observed for perceptions of large scale infrastructural incivilities. Conclusions: Environmental policy needs to give more priority to reducing the incidence of street levelincivilities and the absence of environmental goods, both of which appear to be more important for health than perceptions of large scale infrastructural incivilities

Exciton dynamics in molecular solids from line shape analysis: an assessment of the extent of line shape distortion resulting from use of real crystals

For crystal absorption systems, the line profile of the frequency dependence of the dielectric permittivity ε(ω) contains information about the exciton dynamics that may be studied by the autocorrelation function generated by the Fourier transformation of ε(ω) into the time domain. However, ε(ω) obtained through transforming normal incidence reflectance data R (ω) of a real crystal when the photon-crystal eigenmodes are strongly coupled may be considerably distorted from ε(ω) of a perfect infinite crystal. In this paper, we consider the ways by which such distortions may arise and, by using a model for ε(ω) that might reasonably correspond to the 4000 Å b -polarized 0-0 absorption system at low temperatures of crystalline anthracene probed on the (001) face, we illustrate the dependence of the extent of distortions on the line profile of ε(ω) upon the following number of factors, viz., (i) spatial dispersion of the exciton bands; (ii) use of an oblique angle of incidence as an approximation to normal incidence in determining R (ω); (iii) thickness of the crystal slab used to determine R (ω); (iv) extent of roughness on the crystal surface; (v) mole fraction of defects in the crystal; and (vi) mole fraction of impurities in the crystal. The treatment allows definition of the condition [real ε(ω) < 0] under which various quasiparticles (longitudinal excitons, surface excitons, excitons bound to impurities) may be excited in a particular crystal system. The methods employed in this paper are of general applicability to strongly absorbing crystal systems and will be of use in understanding exciton dynamics in such systems. The data provide a firm foundation for interpreting reflectance data of a strongly absorbing crystal system, and thus we are able to discuss existing spectral data for anthracene crystals, especially narrow structure observed in low temperature reflection spectra, as well as suggest areas for both theoretical and experimental work

Computational purification of individual tumor gene expression profiles leads to significant improvements in prognostic prediction.

Tumor heterogeneity is a limiting factor in cancer treatment and in the discovery of biomarkers to personalize it. We describe a computational purification tool, ISOpure, to directly address the effects of variable normal tissue contamination in clinical tumor specimens. ISOpure uses a set of tumor expression profiles and a panel of healthy tissue expression profiles to generate a purified cancer profile for each tumor sample and an estimate of the proportion of RNA originating from cancerous cells. Applying ISOpure before identifying gene signatures leads to significant improvements in the prediction of prognosis and other clinical variables in lung and prostate cancer

Oil and natural gas reserve prices : addendum to CEEPR WP 03-016 ; including results for 2003 revisions to 2001

Introduction. A working paper entitled "Oil and Natural Gas Reserve Prices 1982-2002: Implications for Depletion and Investment Cost" was published in October 2003 (cited hereafter as Adelman & Watkins [2003]). Since then we have obtained data for 2003 and estimated oil and natural gas reserve prices for that year. We have also revised our previous estimates of reserve prices for 2001. This addendum paper reports on the nature and significance of the results for 2003 and the revisions to 2001. We have also extended the analysis by adding two new features. First is the expression of reserve prices in real terms -- previously we had only reported nominal prices. Second, we have estimated levelized or constant field prices that appear to underlie reserve prices, for each year. We refer to these as planning prices. Previously we had only published estimated growth rates in field prices from levels prevailing for a given year, congruent with our estimates of reserve prices. Section 1 of this Addendum paper highlights the 2003 results. Section 2 discusses the revisions for year 2001. Section 3 outlines the nature of the analytical extensions, presents the results, and discusses what they show. Concluding remarks are in Section 4. Adelman & Watkins [2003] included an extensive set of tables in Appendices. The revisions to all these tables to include 2003 and revised 2001 data are attached here as Appendices. This paper is to be read in conjunction with, not as a substitute for, Adelman & Watkins [2003]: analysis and description in the 2003 paper is not repeated here

Cardiovascular disease and air pollution in Scotland: no association or insufficient data and study design?

&lt;p&gt;&lt;b&gt;Background:&lt;/b&gt; Coronary heart disease and stroke are leading causes of mortality and ill health in Scotland, and clear associations have been found in previous studies between air pollution and cardiovascular disease. This study aimed to use routinely available data to examine whether there is any evidence of an association between short-term exposure to particulate matter (measured as PM10, particles less than 10 micrograms per cubic metre) and hospital admissions due to cardiovascular disease, in the two largest cities in Scotland during the years 2000 to 2006.&lt;/p&gt; &lt;p&gt;&lt;b&gt;Methods:&lt;/b&gt; The study utilised an ecological time series design, and the analysis was based on overdispersed Poisson log-linear models.&lt;/p&gt; &lt;p&gt;&lt;b&gt;Results:&lt;/b&gt; No consistent associations were found between PM10 concentrations and cardiovascular hospital admissions in either of the cities studied, as all of the estimated relative risks were close to one, and all but one of the associated 95% confidence intervals contained the null risk of one.&lt;/p&gt; &lt;p&gt;&lt;b&gt;Conclusions:&lt;/b&gt; This study suggests that in small cities, where air quality is relatively good, then either PM10 concentrations have no effect on cardiovascular ill health, or that the routinely available data and the corresponding study design are not sufficient to detect an association.&lt;/p&gt