1,204 research outputs found
Persistence of chlorpropham (CIPC) in the concrete flooring of potato stores
The loss of the sprout suppressant, chlorpropham (CIPC), to the fabric of potato stores is currently of concern due to the risk of potential cross contamination of other crops subsequently housed in these stores. HPLC UV/VIS and GCMS methods were successfully employed to detect CIPC in the concrete flooring of research and commercial potato stores with histories of between 1 and 26 years of use. The concentrations in identical research stores, with different numbers of applications, were in the range 0.58â5.7 and 3.4â112 ÎŒg gâ1, suggesting the magnitude of contamination was influenced by the number of applications. Commercial store A, with a history of 18 seasons of applications (estimate of total CIPC applied 2040 kg), had concentrations varying between 6 and 48 ÎŒg gâ1 in the top three centimetres, with more than 92% within the top centimetre. In contrast, commercial store B, with a history of less than five seasons of applications (estimate of total CIPC applied 319 kg), had concentrations varying between 0.58 and 304 ÎŒg gâ1 in the top four centimetres, with less than 47% within the top centimetre. The difference in depth distributions between A and B may be due to the structural integrity of the concrete, which was much poorer in B. CIPC was persistent in all stores irrespective of the total quantities of CIPC applied and date of the final application
Factor analysis of treatment outcomes from a UK specialist addiction service:relationship between the Leeds Dependence Questionnaire, Social Satisfaction Questionnaire and 10-item Clinical Outcomes in Routine Evaluation
INTRODUCTION AND AIMS: To examine the relationship between three outcome measures used by a specialist addiction service (UK): the Leeds Dependence Questionnaire (LDQ), the Social Satisfaction Questionnaire (SSQ) and the 10-item Clinical Outcomes in Routine Evaluation (CORE-10). DESIGN AND METHOD: A clinical sample of 715 service user records was extracted from a specialist addiction service (2011) database. The LDQ (dependence), SSQ (social satisfaction) and CORE-10 (psychological distress) were routinely administered at the start of treatment and again between 3 and 12 months post-treatment. A mixed pre/post-treatment dataset of 526 service users was subjected to exploratory factor analysis. Parallel Analysis and the Hull method were used to suggest the most parsimonious factor solution. RESULTS: Exploratory factor analysis with three factors accounted for 66.2% of the total variance but Parallel Analysis supported two factors as sufficient to account for observed correlations among items. In the two-factor solution, LDQ items and nine of the 10 CORE-10 items loaded on the first factor >0.41, and the SSQ items on factor 2 with loadings >0.63. A two dimensional summary appears sufficient and clinically meaningful. DISCUSSION AND CONCLUSIONS: Among specialist addiction service users, social satisfaction appears to be a unique construct of addiction and is not the same as variation due to psychological distress or dependence. Our interpretation of the findings is that dependence is best thought of as a specific psychological condition subsumed under the construct psychological distress. [Fairhurst C, Böhnke JR, Gabe R, Croudace TJ, Tober G, Raistrick D. Factor analysis of treatment outcomes from a UK specialist addiction service: Relationship between the Leeds Dependence Questionnaire, Social Satisfaction Questionnaire and 10-item Clinical Outcomes in Routine Evaluation. Drug Alcohol Rev 2014;33:643â650
An investigation of the relationship between anterior knee pain and lower limb biomechanics.
The thesis presents an investigation of the relationship between anterior knee pain and lower limb biomechanics in symptomatic and asymptomatic individuals during walking. Although foot orthotic devices are often prescribed to realign lower extremity mechanics, there is conflicting evidence to support this. A quantitative study explored the dynamics of walking barefoot, shod and with orthotic devices using the 3D Kinematic Motion Analysis System, Vicon 370. Sample sizes of 30 control subjects and 30 subjects with anterior knee pain were recruited. Kinematic gait parameters and temporal-spatial gait parameters were compared between the two groups and a thorough static clinical examination was provided. The relationship of alignment and knee pain was also examined using the Positional Upright MRI Scanner. A group of 15 subjects with anterior knee pain and a group of 5 asymptomatic subjects were examined radiographically barefoot, shod and with orthotic devices. An increase in Q-angle was shown in the knee pain group with an added angle increase in the females in both groups. This could signify that a higher Q-angle may influence biomechanics of the knee joint by creating an abnormally increased valgus angle. Evidence was found that there was a strong relationship between eversion and inversion of the foot with internal and external tibial rotation of the leg. This coupling relationship may lend insight into the behavior of the lower leg and anterior knee pain whilst walking. Small changes were noted when wearing the orthotic devices which may be advantageous biomechanically and they were also of benefit in correcting pronatory changes or movements more distal to the foot. The results of the MRI study were disappointing but many limitations were shown to support the results. Upon finishing this thesis, it is apparent that documented evidence of any relationship between anterior knee pain and lower limb biomechanics is imperative to clinicians in order to aid in treatment plans of patients but also in preventative treatment. Further research is required to enhance the clinicians knowledge and understanding of the foot and leg dynamically
Segmented sedentary time and physical activity patterns throughout the week from wrist-worn ActiGraph GT3X+ accelerometers among children 7â12 years old
The authors thank the children, schools, teachers, and parents who agreed to participate in this study. Our study was funded by University of the West of Scotland's VP Research Fund. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.Peer reviewedPublisher PD
Effect of alcohol addition on the movement of petroleum hydrocarbon fuels in soil
Groundwater contamination by fuel spills from aboveground and underground storage tanks has been of growing concern in recent years. This problem has been magnified by the addition of oxygenates, such as ethanol and methyl-tertiary-butyl ether (MTBE) to fuels to reduce vehicular emissions to the atmosphere. These additives, although beneficial in reducing atmospheric pollution, may, however, increase groundwater contamination due to the co-solvency of petroleum hydrocarbons and by the provision of a preferential substrate for microbial utilisation. With the introduction of ethanol to diesel fuel imminent and the move away from MTBE use in many states of the USA, the environmental implications associated with ethanol additive fuels must be thoroughly investigated. Diesel fuel movement was followed in a 1-m soil column and the effect of ethanol addition to diesel fuel on this movement determined. The addition of 51% ethanol to diesel fuel was found to enhance the downward migration of the diesel fuel components, thus increasing the risk of groundwater contamination. A novel method using soil packcd HPLC columns allowed the influence of ethanol on individual aromatic hydrocarbon movement to be studied. The levels of ethanol addition investigated were at the current additive level (approx. 25%) for ethanol additive fuels in Brazil and values above (50%) and below (10%) this level. An aqueous ethanol concentration above 10% was required for any movement to occur. At 25% aqueous ethanol, the majority of hydrocarbons were mobilised and the retention behaviour of the soil column lessened. At 50% aqueous ethanol, all the hydrocarbons were found to move unimpeded through the columns. The retention behaviour of the soil was found to change significantly when both organic matter content and silt/clay content was reduced. Unexpectedly, sandy soil with low organic matter and low silt/clay was found to have a retentive behaviour similar to sandy subsoil with moderate silt/clay, but little organic matter. It was concluded that sand grains might have a more important role in the adsorption of petroleum hydrocarbons than first realised. This method has shown that soil packed HPLC columns can be used to provide a quick estimate of petroleum hydrocarbon, and possibly other organic contaminant, movement in a variety of different soil types
An Application of Multi-band Forced Photometry to One Square Degree of SERVS: Accurate Photometric Redshifts and Implications for Future Science
We apply The Tractor image modeling code to improve upon existing multi-band
photometry for the Spitzer Extragalactic Representative Volume Survey (SERVS).
SERVS consists of post-cryogenic Spitzer observations at 3.6 and 4.5 micron
over five well-studied deep fields spanning 18 square degrees. In concert with
data from ground-based near-infrared (NIR) and optical surveys, SERVS aims to
provide a census of the properties of massive galaxies out to z ~ 5. To
accomplish this, we are using The Tractor to perform "forced photometry." This
technique employs prior measurements of source positions and surface brightness
profiles from a high-resolution fiducial band from the VISTA Deep Extragalactic
Observations (VIDEO) survey to model and fit the fluxes at lower-resolution
bands. We discuss our implementation of The Tractor over a square degree test
region within the XMM-LSS field with deep imaging in 12 NIR/optical bands. Our
new multi-band source catalogs offer a number of advantages over traditional
position-matched catalogs, including 1) consistent source cross-identification
between bands, 2) de-blending of sources that are clearly resolved in the
fiducial band but blended in the lower-resolution SERVS data, 3) a higher
source detection fraction in each band, 4) a larger number of candidate
galaxies in the redshift range 5 < z < 6, and 5) a statistically significant
improvement in the photometric redshift accuracy as evidenced by the
significant decrease in the fraction of outliers compared to spectroscopic
redshifts. Thus, forced photometry using The Tractor offers a means of
improving the accuracy of multi-band extragalactic surveys designed for galaxy
evolution studies. We will extend our application of this technique to the full
SERVS footprint in the future.Comment: accepted to ApJ, 22 pages, 12 figure
Development of a sensitive and rapid method for the measurement of total microbial activity using fluorescein diacetate (FDA) in a range of soils
Fluorescein diacetate (FDA) hydrolysis is widely accepted as an accurate and simple method for measuring total microbial activity in a range of environmental samples, including soils. Colourless fluorescein diacetate is hydrolysed by both free and membrane bound enzymes, releasing a coloured end product fluorescein which can be measured by spectrophotometry. The current method for measuring FDA hydrolysis in soils is limited in its application. FDA activity was very low in sandy and clayey soils. The low activity observed for these soil types was made difficult to measure by the original authors choice of solvent for terminating the hydrolysis reaction. Acetone (50% v/v) was found to be most efficient at stopping the hydrolysis reaction. During this study acetone (50% v/v) was found to cause a decrease of approximately 37% in the absorbance of fluorescein produced by the soil samples measured. Although this colour loss is independent of initial fluorescein concentration, it makes the measurement of FDA hydrolytic activity extremely difficult in soils with low microbial activity i.e. sandy and/or clayey soils. Chloroform/methanol (2:1 v/v) was found to successfully stop the hydrolysis reaction for up to 50 min in a range of soil samples without causing the loss of colour observed with acetone. By changing the solvent used for terminating the hydrolysis reaction, low activity soils could be measured successfully. Other parameters of the hydrolysis reaction were optimised for the measurement of soil samples including effect of pH. optimum temperature of incubation, amount of soil, time of incubation, amount of substrate and preparation of suitable standards. A new, more sensitive method is proposed adapted from the original method, which provides a more accurate determination of FDA hydrolysis in a wide range of soils
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