On Chiral Mesons in AdS/CFT

We analyze the spectra of non-chiral and chiral bifundamental mesons arising on intersecting D7-branes in $AdS_{5}\times S^{5}$. In the absence of magnetic flux on the curve of intersection, the spectrum is non-chiral, and the dual gauge theory is conformal in the quenched/probe approximation. For this case we calculate the dimensions of the bifundamental mesonic operators. We then consider magnetization of the D7-branes, which deforms the dual theory by an irrelevant operator and renders the mesons chiral. The magnetic flux spoils the conformality of the dual theory, and induces a D3-brane charge that becomes large in the ultraviolet, where the non-normalizable bifundamental modes are rapidly divergent. An ultraviolet completion is therefore necessary to calculate the correlation functions in the chiral case. On the other hand, the normalizable modes are very well localized in the infrared, leading to new possibilities for local model-building on intersecting D7-branes in warped geometries.Comment: 32 pages, 4 figure

The Greenhouse Gas Impact of Shale Gas Exploitation

Shale gas is a hydrocarbon in impermeable shale rock up to 3.5km below the earth surface, requiring hydraulic fracturing, an ‘unconventional’ technique to stimulate production. This study sought to explore the accurate greenhouse gas impact of shale gas exploitation. Emissions from a producing conventional well pad are analogous to an unconventional well pad in production. Methane emissions were measured at three key sites; the KM5 conventional well pad, Knapton generation station and a rural crop farm control site, Cranford Farm. 288 hours of methane measurements were conducted using a Picarro Ring Down Spectrometer, which recorded methane concentration at 1 hertz. A Gull wind sonic was also used to record wind speed and direction. Therefore a flux could be calculated for two natural gas infrastructure sites for comparison. The control site had an average methane concentration of 1.93 ppm, which was higher than the 1.91 ppm CH4 average at the KM5 well pad but lower than that of Knapton which was 2.01 ppm. The average calculated CH4 flux at KM5 was 24.29 kg CH4/year, 3% of the average flux from Knapton, which was calculated as 847.91 kg CH4/year. These annual methane emissions are the equivalent of 3 sheep and 7 dairy cows respectively. Under highest case calculations, methane emissions from these sites equate to emission factors of 0.0077% for KM5 and 0.082% for Knapton. From literature analysis, pre-production emissions from shale gas exploitation will be higher from a) excess energy required for horizontal drilling and hydraulic fracturing and b) methane emissions from well completion. The extent to which it has a larger environmental impact than conventional gas is dependent on the use of REC (reduced emissions completions), which can reduce well completion methane emissions by over 90%. Over longer terms, the Climate Change Act (2008) requires an 80% reduction in GHG emissions from 1990 levels, which will require CCS implementation nationally regardless of shale gas exploitation

Writing Apprehension of Black Students at a Private Historically Black Four Year Liberal Arts Institution

The purpose of this study was to determine the level of writing apprehension among first generation students at a Private Historically Black Institution. Participants were 103 college students from the central region of Arkansas at a Private Historically Black Institution of which 103 students responded to the survey completely. All of the respondents were administered the survey in four different sections of the freshman seminar courses. The survey consisted of a demographic section and the Writing Apprehension Test. The writing apprehension test was created by Daly and Miller (1975) to determine an individual\u27s level of writing apprehension. Student\u27s views, opinions or suggestions with regard to alleviating their writing apprehension level are also presented. Scores that range from fifty four to ninety are in the normal range. Students in this range do not experience significantly unusual levels of writing apprehension. However the closer the score is to the limit ranges the more apt the student is to experience behaviors or characteristics of the next range of scores. Scores that range from ninety-one to one hundred and twenty-four are in the low range. Students in this range experience low levels of writing apprehension and have no fear of writing. In addition, scores that are between twenty and fifty-four are classified as in the high range. Students in this range avoid writing as much as possible and experiences sever anxiety. According to the research findings almost 70% or 68.9% of the survey participants experienced normal writing apprehension, 10.6% experienced low writing apprehension while 20.3% experienced high writing apprehension. These findings are supported in the literature, statistical data analysis and themes. Based on the findings, the study presents some recommendations to alleviate this problem

Comparison and Review of 17 E-Book Platforms

The University of Michigan Press, with support from the Mellon Foundation, asked John Lavender, of Lavender Consulting, to conduct a review of the American Council of Learned Societies (ACLS) Humanities E-Book collection (HEB) following its launch on Michigan’s new Fulcrum platform. ACLS-HEB is an online collection of over 5,400 high-quality humanities books from over 100 publishers. Now that the market for e-books has matured, part of the review was a comparative study of e-book platforms run by publishers, university presses and e-book vendors; 17 platforms were selected. The review looked at the key features offered by each platform, how they handled searching, content delivery, displaying results, ability to view and download and other key features, there was no attempt to judge the value of the content. Following this review, Michigan Press felt that it would be beneficial to share the results with the wider community. As well as being of interest to publishers, the review will also be relevant for librarians making purchasing decisions and vendors selling e-book services. In addition to synthesizing the results of the e-book platform review, this paper presents a librarian’s perspectives on e-book assessment criteria. Courtney McAllister, Electronic Resources Librarian at Yale University’s Law Library, describes the importance of attributes such as accessibility compliance, library branding, and metadata. Library collections are shaped by a plethora of concerns and criteria. This paper seeks to outline some key elements to consider as part of e-book platform decision-making

Preliminary design of the redundant software experiment

The goal of the present experiment is to characterize the fault distributions of highly reliable software replicates, constructed using techniques and environments which are similar to those used in comtemporary industrial software facilities. The fault distributions and their effect on the reliability of fault tolerant configurations of the software will be determined through extensive life testing of the replicates against carefully constructed randomly generated test data. Each detected error will be carefully analyzed to provide insight in to their nature and cause. A direct objective is to develop techniques for reducing the intensity of coincident errors, thus increasing the reliability gain which can be achieved with fault tolerance. Data on the reliability gains realized, and the cost of the fault tolerant configurations can be used to design a companion experiment to determine the cost effectiveness of the fault tolerant strategy. Finally, the data and analysis produced by this experiment will be valuable to the software engineering community as a whole because it will provide a useful insight into the nature and cause of hard to find, subtle faults which escape standard software engineering validation techniques and thus persist far into the software life cycle