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Search Results: 1 - 10 of 301997 matches for " Mary J. Thornbush "
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A Photo-Based Environmental History of the Use of Climbing Plants in Central Oxford, UK  [PDF]
Mary J. Thornbush
International Journal of Geosciences (IJG) , 2013, DOI: 10.4236/ijg.2013.47102

This paper examines environmental change associated with climbing plants (ivy/creeper) on several historical buildings in central Oxford using archival photographs. ViewFinder from English Heritage was used to access the photo archives in an advanced search of the area of “Oxford” and in the county of “Oxfordshire”. The study includes a variety of buildings, including colleges, churches, chapels, asylums, inns/hotels, factories, a brewery, pubs, a castle as well as architectural elements, such as doorways, cloisters, gates, and walls. The findings reveal that a majority of photographs denoted ivy-/creeper-clad buildings (in nearly 53% of photographs found mostly in the Taunt collection). The greatest abundance of climbing plants was found in the 1880s followed by the 1900s. A further examination of University colleges is warranted due to the earlier and more frequent appearance of ivy/creeper on these buildings.

Measuring Surface Roughness through the Use of Digital Photography and Image Processing  [PDF]
Mary J. Thornbush
International Journal of Geosciences (IJG) , 2014, DOI: 10.4236/ijg.2014.55050

This paper aims to provide a quantitative method that employs image processing in the assessment of surface roughness based on digital photograph field surveys, as in previous studies employing the outdoor integrated digital photography and image processing (O-IDIP) method. Digital photographs were taken on two different days under contrasting outdoor lighting conditions (overcast versus clear sky). Images were captured mounted on a tripod close up to the surface of a 380-year-old wall located at the University of Oxford Botanic Garden in the City of Oxford, UK. Sampling points were established at regular intervals along the border wall and encompassed sections facing west, north, and east, respectively along the survey. Two photographs were taken with a digital camera at each sampling point, one containing a color chart used to calibrate outdoor lighting conditions across images, which was excluded from the other photographic pair. Histogram-based quantification was performed based on images converted to Lab Color mode. The 10-step calibration procedure presented in this paper required more adjustments of contrast. However, more adjustments were not required under a clear sky. Std Dev L measurements were used to establish categories in a simple 3-point roughness index, namely the surface roughness index (SRI). The results denote that pitting did not affect surface roughness measurements. The study shows that it is possible to use Std Dev L measurements to quantify surface roughness on a comparative basis.

A Site-Specific Index Based on Weathering Forms Visible in Central Oxford, UK
Mary J. Thornbush
Geosciences , 2012, DOI: 10.3390/geosciences2040277
Abstract: The authenticity of much of the stone-work along Queen’s Lane in central Oxford, UK presented an opportunity to produce a photographic survey from which a weathering index could be established. This represents a site-specific approach to devising a weathering form. Because it is photo-based, weathering forms are visible for comparison and classification purposes across disciplines. Limestone pertaining to building ashlar and plinths along this roadway, which mainly belong to Queen’s College, St Edmund Hall, New College, and Hertford College, was classified according to this newly introduced weathering index, the size-extent (S-E) index, through consideration of type, size, extent, impact, and trigger. This size- (range) and extent-based classification system enables for the assessment of weathering forms of various types, including soiling and decay features as well as those potentially expected in the presence of vegetation and animals. Weathering forms of a range of sizes were present, with a slightly greater abundance of small types (mm-cm in the micro- to mesoscale) and more discrete types with a low extent. For this location in central Oxford, chemical weathering was found to be the predominant type of soiling and decay.
Cross Cultural Exploration of the Perceived Health Competence Scale  [PDF]
Mary J. Polchert
Open Journal of Nursing (OJN) , 2015, DOI: 10.4236/ojn.2015.57067
Abstract: The eight-item Perceived Health Competence Scale (PHCS) is a measure of self-efficacy in general health management that is used to predict health outcomes and behaviors. The PHCS has been shown to be a reliable and valid instrument but has been used in primarily white European Americans. The PHCS is positively correlated to health status and coping abilities. Younger, healthier populations score higher on the PHCS compared to elderly who are managing chronic illness. This study examined the PHCS in three Midwestern samples: African American elders which revealed two separate factors in PHCS; Native Americans who evaluated the PHCS as a single construct; and a Spanish speaking sample. In the latter sample, findings suggest health competence may be a multi-dimensional construct. Further evaluation of the Spanish version of the PHCS and population characteristics are needed to measure health competence beliefs.
Gender Differences in Employed Job Search: Why Do Women Search Less than Men?  [PDF]
Jeffrey J. Yankow, Mary Jean Horney
Modern Economy (ME) , 2013, DOI: 10.4236/me.2013.47053

Using an extended panel from the National Longitudinal Survey of Youth 1979, this study explores the impact of marriage and children on the employed job search behavior of young workers. Estimation results from a bivariate probit model of employed job search that accounts for the selective nature of participation and employment demonstrate that both marriage and children significantly reduce the likelihood of on-the-job search for women but not for men. We find that married women with children have an employed search probability that is 18 percentage points below that of single women without children. Moreover, both the age and number of children present in the household are important determining factors for women in the decision to conduct on-the-job search. The inhibiting effect of children, however, is only pronounced for married women; single women with children are no less likely to search than single women without children.

Synthetic Feedback Loop Model for Increasing Microbial Biofuel Production Using a Biosensor
Mary E. Harrison,Mary J. Dunlop
Frontiers in Microbiology , 2012, DOI: 10.3389/fmicb.2012.00360
Abstract: Current biofuel production methods use engineered bacteria to break down cellulose and convert it to biofuel. A major challenge in microbial fuel production is that increasing biofuel yields can be limited by the toxicity of the biofuel to the organism that is producing it. Previous research has demonstrated that efflux pumps are effective at increasing tolerance to various biofuels. However, when overexpressed, efflux pumps burden cells, which hinders growth and slows biofuel production. Therefore, the toxicity of the biofuel must be balanced with the toxicity of pump overexpression. We have developed a mathematical model for cell growth and biofuel production that implements a synthetic feedback loop using a biosensor to control efflux pump expression. In this way, the production rate will be maximal when the concentration of biofuel is low because the cell does not expend energy expressing efflux pumps when they are not needed. Additionally, the microbe is able to adapt to toxic conditions by triggering the expression of efflux pumps, which allow it to continue biofuel production. Sensitivity analysis indicates that the feedback sensor model is insensitive to many system parameters, but a few key parameters can influence growth and production. In comparison to systems that express efflux pumps at a constant level, the feedback sensor increases overall biofuel production by delaying pump expression until it is needed. This result is more pronounced when model parameters are variable because the system can use feedback to adjust to the actual rate of biofuel production.
Engineering microbes for tolerance to next-generation biofuels
Mary J Dunlop
Biotechnology for Biofuels , 2011, DOI: 10.1186/1754-6834-4-32
Abstract: Microbes can be engineered to produce biologically-derived replacements for gasoline, diesel, and aviation fuel. Although much research has focused on ethanol as a biogasoline, there are many other biofuels that offer advantages such as high energy density, low freezing point, and compatibility with the existing fuel storage and distribution infrastructure [1-3]. Next-generation biofuels, such as long-chain alcohols, fatty-acid-derived, and isoprenoid-derived fuels offer promise as new biofuels and can be synthesized by microbes. These fuels are being developed as either supplements or drop-in replacements for existing petroleum fuels. Because there is active research on many next-generation fuels, this review highlights general tolerance strategies and discusses areas where mechanisms may only work for certain classes of fuels.Next-generation biofuels have many advantages, but the fuels are often toxic to microorganisms. Therefore, the inherent tolerance of the host may limit production potential. Microbes that can survive in hydrocarbon-rich environments have been isolated [4,5], however these strains are rarely suitable for use as biofuel production hosts. Recent efforts have suggested that it may be possible to transfer tolerance mechanisms to a suitable production strain. The ideal host is a well studied organism with good genetic tools available that can be engineered for both biofuel production and tolerance.It is often assumed that increasing tolerance will improve yields. There are several studies where this is the case [6-8], but also well documented examples where increases in tolerance have no effect or have even decreased yield [9-11]. Because biofuel tolerance is complex, and often intimately linked to general stress response, it can be difficult to predict the effect of a given tolerance strategy.This review highlights recent advances in tolerance engineering for the production of next-generation biofuels. Particular emphasis is placed on targeted app
An Exploration of Metacognition and Its Effect on Mathematical Performance In Differential Equations
Mary J Smith
The Journal of Scholarship of Teaching and Learning , 2013,
Abstract: Research suggests that students who are “metacognitively aware learners” demonstrate better academic performance (Shraw & Dennison, 1994; Md. Yunus & Ali, 2008). In this research, the metacognitive levels for two classes of differential equations students were studied. Students completed a survey adapted from the Metacognitive Awareness Inventory (MAI) (Shraw & Dennison, 1994) at the start of the course. The questions chosen from the MAI were aimed at three components concerning the students’ knowledge about their cognition: declarative knowledge, procedural knowledge, and conditional knowledge. Analysis shows student performance, as measured by the course grade, cannot be predicted by metacognitive awareness levels.
A new mixture model approach to analyzing allelic-loss data using Bayes factors
Manisha Desai, Mary J Emond
BMC Bioinformatics , 2004, DOI: 10.1186/1471-2105-5-182
Abstract: We propose a large class of mixture models for describing the data, and we suggest using Bayes factors to select a reasonable model from the class in order to classify the chromosome arms. Bayes factors are especially useful in the case of testing that the number of components in a mixture model is n0 versus n1. In these cases, frequentist test statistics based on the likelihood ratio statistic have unknown distributions and are therefore not applicable. Our simulation study shows that Bayes factors favor the right model most of the time when tumor suppressor genes are present. When no tumor suppressor genes are present and background allelic-loss varies, the Bayes factors are often inconclusive, although this results in a markedly reduced false-positive rate compared to that of standard frequentist approaches. Application of our methods to three data sets of esophageal adenocarcinomas yields interesting differences from those results previously published.Our results indicate that Bayes factors are useful for analyzing allelic-loss data.The goal of studies of allelic loss is to determine those loci in tumor tissue where genetic material has been lost. A tumor suppressor gene (TSG) is much more likely to lie on a chromosome arm where there has been significant allelic loss than elsewhere [1,2]. The statistical challenge lies in distinguishing between "random" allelic loss that is expected in a tumor cell population and "nonrandom" loss that may be biologically meaningful. This corresponds to determining whether there is one group of arms with background allelic loss versus two groups of arms, one with background loss rates and one with elevated loss rates.Esophageal adenocarcinoma is a form of cancer involving the cells along the lining of the esophagus. The cause of esophageal adenocarcinoma is not well understood. The incidence of this cancer has been increasing rapidly. In fact, it is one of the fastest growing cancers in the United States over the past 20 years [
Island Communities and Biotechnology
DaSilva,Edgar J.; Taylor,Mary;
Electronic Journal of Biotechnology , 1998,
Abstract: in the run-up to the year 2000 and beyond, several island countries, especially in the caribbean and pacific regions, are confronted by the challenges and threats of globalization. in response, several island countries are initiating self-reliant strategies aimed at national and regional endogenous development. amongst these strategies, the potential of biotechnology for economic development and technological growth is being tapped.
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