2,212 research outputs found
Groundwater in Carboniferous carbonates : Field excursion to the Derbyshire "White Peak" District 26th June 2015
Carbonate rocks of Carboniferous (largely Viséan) age crop out widely in England and Wales but many of the outcrops
are scattered and broken (Figure 1). The Peak District is one of six contiguous areas, the others being the Yorkshire Dales,
the Northern Pennines, the Mendip Hills, South Wales (including the Forest of Dean) and North Wales (Gunn et al., 1998).
These areas have commonly been regarded by hydrogeologists as having karstic drainage, whereas geologically more
recent carbonates such as those deposited in Jurassic and Cretaceous times are commonly regarded as not being karst or, at
best, 'weakly karstic'. In particular, there has been a tendency to equate karst drainage with surface landforms and to use
'caves as a measure of karst'. Hence, those carbonates with visually impressive surface karst landforms (dolines, blind and
dry valleys) where there are well-developed and extensive cave systems are commonly assumed to have karstic
hydrogeology and those without these landforms are assumed to be 'non-karstic'. One weakness of this simplistic approach
is that caves in carbonates are simply conduits that have been enlarged by dissolution to a point where humans can explore
them. Water flowing though a conduit that is, say, 0.2m in diameter and hence un-enterable will not behave any differently
if after some distance the conduit attains a diameter of 0.4m and can be visited by humans. There is also an increased
awareness that the marked spatial heterogeneity in carbonates at small scale (commonly expressed in terms of dual or
tertiary porosity and permeability) is also present at the field scale. Hence, even the most karstic of regions, where
groundwater moves through conduits and caves at velocities in the hundreds of metres per hour, is likely to also have areas
where there are few conduits and where groundwater velocities may be as little as a few metres per day. The Derbyshire
"White Peak" district provides an excellent location in which to discuss these concepts and their importance to
management or water and mineral resources
Karst cathcment protection : The Cuilcagh Mountain Park initiative, county Fermanagh, Northern Ireland
The Development of an ELISA Test for the Detection of Mycoplasma bovis Antigen in Milk
The objective of the work presented in this thesis was the construction of an ELISA test for the detection of Mycoplasma bovis antigen in milk samples. Consequently, monoclonal antibodies to M. bovis were prepared for use in the ELISA. Whole cell antigen was used to immunise two BALB/c or BALB/c hybrid mice from which serum and spleen cells were harvested. Fusion was carried out with NSO myeloma cell lines and 441 hybridomas were produced. One hundred and fifty-one of these produced antibody to an bovis antigen at levels twice background. The test used for detection and screening of hybridomas was an ELISA constructed with a membrane antigen of approximately 30 kD. Antigen for these bovis screening tests was prepared by the ultrasonic disruption of whole cell suspensions of M. bovis grown in media containing mouse serum. The membrane fractions were harvested by ultracentrifugation at 34 000 g for 30 minutes, resuspended in 10 mM TRIS-HCl buffer, pH 7.8, treated with the chaotropic agent guanidinium thiocyanate (6.0 M) and dialysed against 6.0 M urea. The resulting solubilised antigen was designated antigen "i.p." and used in the screening ELISA . Six antibody-producing hybridomas were cloned further to produce 210 stage-1 clones from which 6 monoclonal antibody lines were produced. Monoclonal antibody (MAb) "5G4" proved to be directed against media constituents but the remaining 5 were directed against M. bovis antigen. MAb "5A10" contained IgG1 with a titre in excess of 1/1000 and was selected for use in the final ELISA. The final ELISA was constructed using MAb "5A10" as capture antibody at a dilution of 1/1000. The same antibody was biotinylated for use at 1/500 as developing antibody. O-phenylenediamine dihydrochloride was used as the substrate and 2.5 M sulphuric acid as the stopping agent. It was evaluated against cultures of 34 isolates from 20 mycoplasma species. Absorption greater than twice background was only noted in the M. bovis and one M. agalactiae isolates. The occurrence of the same antigen in the two species does not prevent the use of this ELISA in the detection of M. bovis in bovine mastitis as M. aqalactiae does not occur in this species. Serial dilutions of broth cultures of M. bovis sc38, the strain against which the monoclonal antibodies were produced, were examined by ELISA and culture. The level of detection was found to be 10 8 cfu/ml. Milk samples from cows which had been infected experimentally with an East German isolate of M. bovis were supplied by Dr H Pfutzner, Jena, in frozen form together with information about the numbers of mycoplasmal cfu present at the time of sampling. 78 milk samples from 6 cows were examined for M. bovis antigen using the ELISA, and for N-acetylglucosaminidase (NAGase) using an ELISA available at Stormont. The ELISA detected bovis in milks which had an original concentration of 10e7 cfu/ml. ELISA results were positive for milks taken between days 3 and 21 (Cow 1); 7 and 38 (Cow 2); 7 and 10 (Cow 3); 7 and 38 (Cow 8) ; and 7 and 10 (Cow 9) . Cow 7 was negative both by ELISA and culture. The NAGase results were positive over a longer period than the M. bovis ELISA results
Late-successional and old-growth forests in the northeastern United States: Structure, dynamics, and prospects for restoration.
Abstract
Restoration of old-growth forest structure is an emerging silvicultural goal, especially in those regions where old-growth abundance falls below the historic range of variability. However, longitudinal studies of old-growth dynamics that can inform silvicultural and policy options are few. We analyzed the change in structure, including stand density, diameter distribution, and the abundance of large live, standing dead, and downed dead trees on 58 late-successional and old-growth plots in Maine, USA, and compared these to regional data from the U.S. Forest Inventory and Analysis program. Structural dynamics on the late-successional plots reflected orderly change associated with density-dependent growth and mortality, but dynamics on the old-growth plots were more variable. Some plots experienced heavy mortality associated with beech bark disease. Diameter distributions conformed poorly to a classic exponential distribution, and did not converge toward such a distribution at the plot scale. Although large live trees showed a broad trend of increasing density in regional forests, recent harvesting patterns offset a considerable fraction of those gains, while mean diameter was static and the number of large dead trees was weakly declining. Even though forests of the northeast are aging, changes in silviculture and forest policy are necessary to accelerate restoration of old-growth structure
The Homeric house in the light of recent excavations
Typescript"This thesis is approved by me for the degree of master of arts W.G. Manly"Last 11 leaves are blankM.A. University of Missouri 1904The purpose of this paper is to give a detailed description of the Homeric house, according to the information to be had from the Homeric poems, and to compare it with other palaces of early antiquity, such as those of Tiryns, Mycenae, Knossos and Phaistos
Bandwidth enhancement : correcting magnitude and phase distortion in wideband piezoelectric transducer systems
Acoustic ultrasonic measurements are widespread and commonly use transducers exhibiting
resonant behaviour due to the piezoelectric nature of their active elements, being designed
to give maximum sensitivity in the bandwidth of interest. We present a characterisation of
such transducers that provides both magnitude and phase information describing the way in
which the receiver responds to a surface displacement over its frequency range. Consequently,
these devices work efficiently and linearly over only a very narrow band of their overall
frequency range. In turn, this causes phase and magnitude distortion of linear signals. To
correct for this distortion, we introduce a software technique, which considers only the input
and the final output signals of the whole systemwhich is therefore generally applicable to any
acoustic system. By correcting for the distortion of the magnitude and phase responses, we
have ensured the signal seen at the receiver replicates the desired signal. We demonstrate a
bandwidth extension on the received signal from 60-130 kHz at -6dB to 40-200 kHz at -1dB
in a test system. The linear chirp signal we used to demonstrate this method showed the
received signal to be almost identical to the desired linear chirp. Such systemcharacterisation
will improve ultrasonic techniques when investigating material properties by maximising the
accuracy of magnitude and phase estimations
Northern Forest Watershed Incentives Project (2010 State of the Bay Presentation)
https://digitalcommons.usm.maine.edu/cbep-presentations/1070/thumbnail.jp
Notices of Remains of Ecclesiastical Architecture in Norfolk, Supposed to be of the Saxon Period
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Combining social and nutritional perspectives: from adolescence to adulthood (the ASH30 study)
Purpose
The purpose of this paper is to focus specifically on the benefits of using mixed methods to investigate dietary change from adolescence to adulthood exemplified using the findings from the ASH30 longitudinal study. The ASH30 study is a longitudinal dietary survey which provided quantitative evidence of dietary change and investigated factors influencing dietary change from adolescence to adulthood.
Design/methodology/approach
Two three-day food diaries were collected both in 1980 (aged 11-12 years) and 2000 (aged 31-32 years) from the same 198 respondents in North East England. In 2,000 questionnaires were used to collect perceptions of, and attributions for, dietary change and open-ended responses were analysed using content analysis.
Findings
The use of mixed methods brings added breadth and depth to the research which cannot be achieved by a single discipline or method. Determining what has influenced change in dietary behaviour from adolescence to adulthood is a complex and multifaceted task. Eating habits are influenced by multiple factors throughout the life course. Change in food intake between adolescence and adulthood related to life-course events and trajectories. The qualitative findings highlighted relevant contextual information such as themes of moral panics, the concept of âconvenienceâ and âfreshâ foods.
Practical implications
Adopting mixed method approaches to exploring dietary change should offer a rich perspective from which to base realistic interventions.
Originality/value
Longitudinal dietary surveys present an opportunity to understand the complex process of dietary change throughout the life course in terms both of how diets have changed but also of why they have changed
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