2,641 research outputs found
Carboxyhaemoglobin concentration, smoking habit, and mortality in 25 years in the Renfrew/Paisley prospective cohort study
Objective: To investigate how carboxyhaemoglobin concentration is related to smoking habit and to assess whether carboxyhaemoglobin concentration is related to mortality.
Design: Prospective cohort study.
Setting: Residents of the towns of Renfrew and Paisley in Scotland.
Participants: The whole Renfrew/Paisley study, conducted between 1972 and 1976, consisted of 7048 men and 8354 women aged 45–64 years. This study was based on 3372 men and 4192 women who were screened after the measurement of carboxyhaemoglobin concentration was introduced about halfway through the study.
Main outcome measures: Deaths from coronary heart disease (CHD), stroke, chronic obstructive pulmonary disease (COPD), lung cancer, and all causes in 25 years after screening.
Results: Carboxyhaemoglobin concentration was related to self reported smoking and for each smoking category was higher in participants who reported inhaling than in those who reported not inhaling. Carboxyhaemoglobin concentration was positively related to all causes of mortality analysed (relative rates associated with a 1 SD (2.93) increase in carboxyhaemoglobin for all causes, CHD, stroke, COPD, and lung cancer were 1.26 (95% confidence interval (CI) 1.19 to 1.34), 1.19 (95% CI 1.13 to 1.26), 1.19 (95% CI 1.13 to 1.26), 1.64 (95% CI 1.47 to 1.84), and 1.69 (95% CI 1.60 to 1.79), respectively). Adjustment for self reported cigarette smoking attenuated the associations but they remained relatively strong.
Conclusions: Self reported smoking data were validated by the objective measure of carboxyhaemoglobin concentration. Since carboxyhaemoglobin concentration remained associated with mortality after adjustment for smoking, carboxyhaemoglobin seems to capture more of the risk associated with smoking tobacco than does self reported tobacco consumption alone. Analysing mortality by self reported cigarette smoking underestimates the strength of association between smoking and mortality
Alcohol consumption and mortality from all causes, coronary heart disease, and stroke: results from a prospective cohort study of Scottish men with 21 years of follow up
Objectives: To relate alcohol consumption to mortality.
Design: Prospective cohort study.
Setting: 27 workplaces in the west of Scotland.
Participants: 5766 men aged 35-64 when screened in 1970-3 who answered questions on their usual weekly alcohol consumption.
Main outcome measures: Mortality from all causes, coronary heart disease, stroke, and alcohol related causes over 21 years of follow up related to units of alcohol consumed per week.
Results: Risk for all cause mortality was similar for non-drinkers and men drinking up to 14 units a week. Mortality risk then showed a graded association with alcohol consumption (relative rate compared with non-drinkers 1.34 (95% confidence interval 1.14 to 1.58) for 15-21 units a week, 1.49 (1.27 to 1.75) for 22-34 units, 1.74 (1.47 to 2.06) for 35 or more units). Adjustment for risk factors attenuated the increased relative risks, but they remained significantly above 1 for men drinking 22 or more units a week. There was no strong relation between alcohol consumption and mortality from coronary heart disease after adjustment. A strong positive relation was seen between alcohol consumption and risk of mortality from stroke, with men drinking 35 or more units having double the risk of non-drinkers, even after adjustment.
Conclusions: The overall association between alcohol consumption and mortality is unfavourable for men drinking over 22 units a week, and there is no clear evidence of any protective effect for men drinking less than this
Cementitious grouts for intermediate level nuclear waste (ILW) encapsulation - effect of compositional changes upon hydration
Grouts containing high levels of replacement by BFS are the preferred route to disposal for a large majority of ILW in the UK. A number of techniques, SEM image analysis, chemical shrinkage, ICC, TGA and XRD, have been applied to assess the rate and degree of hydration of such cementitious grouts. This study forms a base for quantifying the effects of modifications to the physical and chemical composition of both the OPC and the BFS components of the matrix in order to identify the sensitivity or otherwise of the technique to ensure that a continuity of supply is maintained
The semantic effects of verb raising and its consequences in second language grammars
This article considers whether highly proficient second language speakers of English can distinguish meaning contrasts associated with constructions where there is a raising be, and constructions where there is a non-raising thematic verb, as illustrated in the difference between (1a) and (1b): 1a. Kim is reading a novel (`event-in-progress/existential ? interpretation
Flow Visualization Tests of a 0.004-scale Space Shuttle Vehicle 2A Model (no. 13-OTS) in the MSFC 14-inch Trisonic Wind Tunnel (IS6A)
Documented are representative photographs of surface flow patterns, created by oil flow and shadowgraph techniques, obtained during wind tunnel tests of an 0.004-scale version of the 2A SSV orbiter. The purpose of this test series was to obtain flow visualization photographs to aid in interpretation of test IS1 aero-noise data. The test was conducted at nominal Mach numbers from 0.6 to 3.48. The orbiter was run in proximity to the external tank and solid rocket boosters at angles of attack from -5 deg to +9 deg at 0 deg angle of sideslip
Does degradation from selective logging and illegal activities differently impact forest resources? A case study in Ghana
Degradation, a reduction of the ecosystem’s capacity to supply goods and services, is widespread in tropical forests and mainly caused by human disturbance. To maintain the full range of forest ecosystem services and support the development of effective conservation policies, we must understand the overall impact of degradation on different forest resources. This research investigates the response to disturbance of forest structure using several indicators: soil carbon content, arboreal richness and biodiversity, functional composition (guild and wood density), and productivity. We drew upon large field and remote sensing datasets from different forest types in Ghana, characterized by varied protection status, to investigate impacts of selective logging, and of illegal land use and resources extraction, which are the main disturbance causes in West Africa. Results indicate that functional composition and the overall number of species are less affected by degradation, while forest structure, soil carbon content and species abundance are seriously impacted, with resources distribution reflecting the protection level of the areas. Remote sensing analysis showed an increase in productivity in the last three decades, with higher resiliency to change in drier forest types, and stronger productivity correlation with solar radiation in the short dry season. The study region is affected by growing anthropogenic pressure on natural resources and by an increased climate variability: possible interactions of disturbance with climate are also discussed, together with the urgency to reduce degradation in order to preserve the full range of ecosystem functions
The relationship between mineral composition, crystal structure and paragenetic sequence: the case of secondary Te mineralization at the Bird Nest drift, Otto Mountain, California, USA
Extended performance solar electric propulsion thrust system study. Volume 4: Thruster technology evaluation
Several thrust system design concepts were evaluated and compared using the specifications of the most advanced 30 cm engineering model thruster as the technology base. Emphasis was placed on relatively high power missions (60 to 100 kW) such as a Halley's comet rendezvous. The extensions in thruster performance required for the Halley's comet mission were defined and alternative thrust system concepts were designed in sufficient detail for comparing mass, efficiency, reliability, structure, and thermal characteristics. Confirmation testing and analysis of thruster and power processing components were performed, and the feasibility of satisfying extended performance requirements was verified. A baseline design was selected from the alternatives considered, and the design analysis and documentation were refined. The baseline thrust system design features modular construction, conventional power processing, and a concentrator solar array concept and is designed to interface with the Space Shuttle
Novel metered aerosol valve
The design and performance of a new valving mechanism for portable pressurized spraying devices is described, where
the propellant in the device is a safe gas (so-called compressed gas) propellant rather than the current liquefied gases all
of which are either volatile organic compounds or greenhouse gases. The valve sprays a fixed volume of liquid when the
spraying actuator is depressed, as is essential used medical sprays, such as pressurized metered dose inhalers and nasal
sprays, and also for automatic (wall-mounted) aerosol delivery systems for air-fresheners, insecticides and disinfectants.
For ‘compressed gas’ aerosol formats, there is no flash vaporization of propellant so that pumping liquid from a metering
chamber and atomization to form a spray must be achieved entirely by designing some means of using the pumping action
of the gas in the container to act upon the liquid in the metering chamber. The new design utilizes a loosely fitting
spherical piston element and a simple arrangement of a concentric housing and a moveable valve stem, such that liquid
flow paths between the different elements are automatically closed and opened in the correct time sequence when the
valve stem is depressed and released. Spraying data show excellent repeatability of liquid sprayed per pulse throughout
the lifetime of device and drop sizes that are acceptable for devices such as air-fresheners and nasal sprays. The valve has
only one additional component compared with liquefied gas metered valves and can be straightforwardly injection
moulded. As will be explained, previous attempts failed due to expense, complexity and unreliability.
Keywords
Aerosol valve, spray metering, insert, inhaler, air-freshene
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