Measurement and prediction of the effect of students activities on airborne particulate concentration in a classroom.

Epidemiological studies have shown links between human exposure to indoor airborne particles and adverse health affects. Several recent studies have also reported that the classroom environment has an impact on students’ health and performance. In this study particle concentration in a university classroom is assessed experimentally for different occupancy periods. The mass concentrations of different particle size ranges (0.3 – 20 µm), and the three particulate matter fractions (PM10, PM2.5, and PM1) were measured simultaneously in a classroom with different occupancy periods including occupied and unoccupied periods in the University of Reading, UK, during the winter period of 2010. The results showed that students’ presence is a significant factor affecting particles concentration for the fractions above PM1 in the measured range of 0.3 to 20 µm. The resuspension of the three PM fractions was also determined in the study.

Measurement of apolipoprotein B-48 in the Svedberg flotation rate (Sf) > 400, Sf 60 – 400 and Sf 20 – 60 lipoprotein fractions reveals novel findings with respect to the effects of dietary fatty acids on triacylglycerol-rich lipoproteins in postmenopausal women

The present study was designed to examine whether the type of fat ingested in an initial test meal influences the response and density distribution of dietary-derived lipoproteins in the Svedberg flotation rate (Sf)>400, Sf 60 - 400 and Sf 20 - 60 lipoprotein fractions. A single-blind randomized within-subject crossover design was used to study the effects of palm oil, safflower oil, a mixture of fish and safflower oil, and olive oil on postprandial apolipoprotein (apo) B-48, retinyl ester and triacylglycerol responses in each lipoprotein fraction following an initial test meal containing one of the oils and a second standardized test meal. For all dietary oils, late postprandial (300min) concentrations of triacylglycerol and apo B-48 were significantly higher in the Sf 60 - 400 fraction than in the Sf>400 fraction (P<0.02). Significantly greater apo B-48 incremental areas under the curve (IAUCs) were also observed in the Sf 60 - 400 fraction than in the Sf>400 fraction following palm oil, safflower oil and olive oil (P<0.04), with a similar non-significant trend for fish/safflower oil. Olive oil resulted in a significantly greater apo B-48 IAUC in the Sf>400 fraction (P<0.02) than did any of the other dietary oils, as well as a tendency for a higher IAUC in the Sf 60 - 400 fraction compared with the palm, safflower and fish/safflower oils. In conclusion, we have found that the majority of intestinally derived lipoproteins present in the circulation following meals enriched with saturated, polyunsaturated or monounsaturated fatty acids are of the density and size of small chylomicrons and chylomicron remnants. Olive oil resulted in a greater apo B-48 response compared with the other dietary oils following sequential test meals, suggesting the formation of a greater number of small (Sf 60 - 400) and large (Sf>400) apo B-48-containing lipoproteins in response to this dietary oil.

Means, motive and opportunity? Disentangling client influence on performance measurement appraisals

This paper investigates the extent to which clients were able to influence performance measurement appraisals during the downturn in commercial property markets that began in the UK during the second half of 2007. The sharp change in market sentiment produced speculation that different client categories were attempting to influence their appraisers in different ways. In particular, it was recognised that the requirement for open-ended funds to meet redemptions gave them strong incentives to ensure that their asset values were marked down to market. Using data supplied by Investment Property Databank, we demonstrate that, indeed, unlisted open ended funds experienced sharper drops in capital values than other fund types in the second half of 2007, after the market turning point. These differences are statistically significant and cannot simply be explained by differences in portfolio composition. Client influence on appraisal forms one possible explanation of the results observed: the different pressures on fund managers resulting in different appraisal outcomes.

Farm forestry in Pakistan: an application of Theory of Planned Behaviour by probing into the measurement issues

A research has been conducted over methodological issues concerning the Theory of Planned Behaviour (TPB) by determining an appropriate measurement (direct and indirect) of constructs and selection of a plausible scaling techniques (unipolar and bipolar) of constructs: attitude, subjective norm, perceived behavioural control and intention that are important in explaining farm level tree planting in Pakistan. Unipolar scoring of beliefs showed higher correlation among the constructs of TPB than bipolar scaling technique. Both direct and indirect methods yielded significant results in explaining intention to perform farm forestry except the belief based measure of perceived behavioural control, which were analysed as statistically non-significant. A need to examine more carefully the scoring of perceived behavioural control (PBC) has been expressed

Motivation, rationale and key results from the GERBILS Saharan dust measurement campaign

The Geostationary Earth Radiation Budget Intercomparison of Longwave and Shortwave radiation (GERBILS) was an observational field experiment over North Africa during June 2007. The campaign involved 10 flights by the FAAM BAe-146 research aircraft over southwestern parts of the Sahara Desert and coastal stretches of the Atlantic Ocean. Objectives of the GERBILS campaign included characterisation of mineral dust geographic distribution and physical and optical properties, assessment of the impact upon radiation, validation of satellite remote sensing retrievals, and validation of numerical weather prediction model forecasts of aerosol optical depths (AODs) and size distributions. We provide the motivation behind GERBILS and the experimental design and report the progress made in each of the objectives. We show that mineral dust in the region is relatively non-absorbing (mean single scattering albedo at 550 nm of 0.97) owing to the relatively small fraction of iron oxides present (1–3%), and that detailed spectral radiances are most accurately modelled using irregularly shaped particles. Satellite retrievals over bright desert surfaces are challenging owing to the lack of spectral contrast between the dust and the underlying surface. However, new techniques have been developed which are shown to be in relatively good agreement with AERONET estimates of AOD and with each other. This encouraging result enables relatively robust validation of numerical models which treat the production, transport, and deposition of mineral dust. The dust models themselves are able to represent large-scale synoptically driven dust events to a reasonable degree, but some deficiencies remain both in the Sahara and over the Sahelian region, where cold pool outflow from convective cells associated with the intertropical convergence zone can lead to significant dust production.

A study of the ethene-ozone reaction with photoelectron spectroscopy: measurement of product branching ratios and atmospheric implications

The ozone-ethene reaction has been investigated at low pressure in a flow-tube interfaced to a u.v. photoelectron spectrometer. Photoelectron spectra recorded as a function of reaction time have been used to estimate partial pressures of the reagents and products, using photoionization cross-sections for selected photoelectron bands of the reagents and products, which have been measured separately. Product yields compare favourably with results of other studies, and the production of oxygen and acetaldehyde have been measured as a function of time for the first time. A reaction scheme developed for the ozone-ethene reaction has been used to simulate the reagents and products as a function of time. The results obtained are in good agreement with the experimental measurements. For each of the observed products, the simulations allow the main reaction (or reactions) for production of that product to be established. The product yields have been used in a global model to estimate their global annual emissions in the atmosphere. Of particular interest are the calculated global annual emissions of formaldehyde (0.96 ± 0.10 Tg) and formic acid, (0.05 ± 0.01 Tg) which are estimated as 0.04% and 0.7% of the total annual emission respectively.

A study of the atmospherically relevant reaction between molecular chlorine and dimethylsulfide (DMS): establishing the reaction intermediate and measurement of absolute photoionization cross-sections

In a study using UV photoelectron spectroscopy (PES) of the atmospherically relevant reaction CH3SCH3 + Cl2 → CH3SCH2Cl + HCl bands associated with a reaction intermediate have been observed. These have been assigned to ionization of the covalently bound molecule (CH3)2SCl2 on the basis of the intensity of the observed bands as a function of reaction time, molecular orbital calculations of vertical ionization energies and evidence from infrared spectroscopy. A method has also been developed, with the flow-tube/PE spectrometer combination used, to measure photoionization cross-sections of the reagents and products at the photon energy utilized and this has allowed the photoionization cross-section of the intermediate to be estimated. This work augments an earlier study in which the rate constant of the reaction between CH3SCH3 (DMS) and Cl2 has been measured at room temperature.

Minimum recovery time between reactive hyperemia stimulus in the repeated measurement of brachial flow-mediated dilatation.

The ability to undertake repeat measurements of flow-mediated dilatation (FMD) within a short time of a previous measurement would be useful to improve accuracy or to repeat a failed initial procedure. Although standard methods report that a minimum of 10 min is required between measurements, there is no published data to support this. Thirty healthy volunteers had five FMD measurements performed within a 2-h period, separated by various time intervals (5, 15 and 30 min). In 19 volunteers, FMD was also performed as soon as the vessel had returned to its baseline diameter. There was no significant difference between any of the FMD measurements or parameters across the visits indicating that repeat measurements may be taken after a minimum of 5 min or as soon as the vessel has returned to its baseline diameter, which in some subjects may be less than 5 min.