Simulation studies of the imaging atmospheric cherenkov technique using the Durham mark 6 and H.E.S.S. stand-alone telescopes

The subject of this thesis is the simulation study of the development of extensive air show ers produced by very high energy gamma-ray and hadronic cosmic rays with respect to the Cherenkov light they produce, and its imaging in ground based telescopes. Chapters 1-4 are introductory: Chapter 1 covers the mechanisms responsible for the production of very high energy gamma-rays, whereas, chapter 2 focusses on the development of extensive air showers and Cherenkov light production. Chapter 3 covers the instrumentation used to measure the Cherenkov light using the imaging atmospheric Cherenkov technique. Chapter 4 covers known and possible sources of very high energy gamma-rays. Chapters 5, 6 and 7 cover research performed by the author: Chapter 5 discusses some of the differences between three popular extensive air shower simulations codes, namely ALTAI, CORSIKA and MOCCA. Chapter 6 details the simulation of the response of two ground based imaging atmospheric Cherenkov telescope (the Durham Mark 6 and stand-alone H.E.S.S. telescopes), and in particular details the derivation of the flux of the x-ray selected BL-LAC PKS 2155-304 with the Durham Mark 6 telescope. This represents the refinement of a published measurement given an improved telescope simulation. The significance of the signal seen is 6.8o, and the integral flux derived above 1.5 TeV (assuming a differential spectral slope of-2.6) is {2.5±0.7stat ± (^0.5)(_1.6syst) x 10(^-7) photons m(^-2) s(^-1) Chapter 7 discusses the importance of the atmosphere, and the results of shower simulations under different atmospheric assumptions are presented, which indicate the importance of atmospheric calibration for the new generation of Cherenkov telescopes. The results of this chapter suggest that to first order large changes in the low level aerosol concentration have a much more significant effect on the trigger rate of a stand-alone H.E.S.S. telescope, than on the Hillas parameter distributions seen. Chapter 8 brings together the work done in this thesis, and highlights a final set of fluxes for the active galactic nuclei sources seen with the Durham Mark 6 telescope, many of which will form future sources to be measured with the H.E.S.S. system. The current status of the stand-alone H.E.S.S. system is also covered in chapter 8. The thesis concludes with a further brief discussion of the future prospects for imaging atmospheric Cherenkov astronomy

Can I have a word please: Strategies to enhance understanding of subject specific language in chemistry by international and non-traditional students

In this paper we discuss the outcomes of our research into effective teaching strategies to enhance understanding of subject specific language by international and non-traditional students. Teaching strategies with an emphasis on improving scientific literacy were trialled over the course of the academic year 2010/11 in foundation level chemistry. The outcomes from this research led to the development of an E-glossary to support the development of subject language understanding. The E-glossary was trialled over the academic year 2011/12. It consists of student generated content (with over 100 contributions) explaining scientific terms and concepts in a variety of ways at an appropriate level for foundation students. The outcomes of this research are considered in relation to the development of scientific literacy and conceptual understanding

A Translational Approach to Digital Learning Innovation: Enabling Digital Innovation at Durham University

In this paper we explore how we adopted a translational approach to educational development, which incorporates educational and digital innovation, staff development and student support into a single department. Through exploring three case studies of innovative work, we highlight the key enablers that a translational approach provides such as the agility to undertake research work which can quickly feed into teaching and learning practice. By rethinking the traditional role of learning technologists and by embedding students as partners, we believe such as approach can reap dividends on allowing for meaningful digital innovation in learning and teaching

The detection of Fermi AGN above 100 GeV using clustering analysis

The density-based clustering algorithm DBSCAN has been applied to the Fermi Large Area Telescope (LAT) data set of Eγ ≥ 100 GeV events with |b| > 10°, in order to search for new very high energy (VHE) γ-ray sources. The clustering analysis returned 49 clusters, of which 21 correspond to already known VHE-emitting active galactic nuclei (AGN) within the TeVCat catalogue and a further 11 were found to be significant in a full Fermi analysis. Of these, two are previously detected Fermi VHE AGN, and nine represent new VHE sources consisting of six BL Lac objects, one blazar of unknown type and two unassociated sources. Comparing these, along with the VHE AGN RBS 0679 and RBS 0970 previously detected with Fermi-LAT, to the current populations of AGN detected with ground-based instruments and Fermi suggests that the VHE-emitting AGN discovered in this study are very similar to the TeVCat AGN and therefore further observations with ground-based imaging atmospheric Cherenkov telescopes are recommended

The Effect of the Chirp Wheel and Other Ergogenic Aids on Back Flexion and Recovery

Foam rollers are used frequently as tools by health professionals and athletes to increase joint range of motion, tissue temperature, and blood flow, providing myofascial relief to areas targeted by the user. Standard foam rollers have been the subject of many studies, with limited work regarding foam rolling of the spine, despite this technique being a common practice among athletes. The chirp wheel is a foam rolling product with a groove down the middle, made to increase pressure on deep back muscles which may act to decrease muscle tension and soreness while optimizing perceived recovery. To our knowledge, this is the first study examining the effectiveness of the chirp wheel. Hope College football players were recruited to take part in this 4-week, 5-session counterbalanced study. The first data session consisted of participant information collection and familiarization while the final four sessions involved weightlifting regimens followed by structured recovery and sit and reach tests. Recovery treatments included the application of either a standard foam roller, chirp wheel, or yoga block to muscles in the gluteal, lumbar, thoracic, cervical, and full back regions. Additionally, in each session perceived relief was recorded immediately after working out, post-treatment (standard foam roller, chirp wheel, or yoga block), and 24 hours after the session. The yoga block was used as a placebo to reduce expectancy error. It was hypothesized that the chirp wheel would provide the greatest increase in lumbar flexion and perceived relief, followed by the standard foam roller and yoga block conditions. Significant results would validate company claims regarding the chirp wheel and would support the preferential use of the chirp wheel in foam rolling of the back. This study is ongoing, results will be available during the celebration

TRAIL-induced variation of cell signaling states provides nonheritable resistance to apoptosis.

TNFα-related apoptosis-inducing ligand (TRAIL), specifically initiates programmed cell death, but often fails to eradicate all cells, making it an ineffective therapy for cancer. This fractional killing is linked to cellular variation that bulk assays cannot capture. Here, we quantify the diversity in cellular signaling responses to TRAIL, linking it to apoptotic frequency across numerous cell systems with single-cell mass cytometry (CyTOF). Although all cells respond to TRAIL, a variable fraction persists without apoptotic progression. This cell-specific behavior is nonheritable where both the TRAIL-induced signaling responses and frequency of apoptotic resistance remain unaffected by prior exposure. The diversity of signaling states upon exposure is correlated to TRAIL resistance. Concomitantly, constricting the variation in signaling response with kinase inhibitors proportionally decreases TRAIL resistance. Simultaneously, TRAIL-induced de novo translation in resistant cells, when blocked by cycloheximide, abrogated all TRAIL resistance. This work highlights how cell signaling diversity, and subsequent translation response, relates to nonheritable fractional escape from TRAIL-induced apoptosis. This refined view of TRAIL resistance provides new avenues to study death ligands in general

Mandated data archiving greatly improves access to research data

The data underlying scientific papers should be accessible to researchers both now and in the future, but how best can we ensure that these data are available? Here we examine the effectiveness of four approaches to data archiving: no stated archiving policy, recommending (but not requiring) archiving, and two versions of mandating data deposition at acceptance. We control for differences between data types by trying to obtain data from papers that use a single, widespread population genetic analysis, STRUCTURE. At one extreme, we found that mandated data archiving policies that require the inclusion of a data availability statement in the manuscript improve the odds of finding the data online almost a thousand-fold compared to having no policy. However, archiving rates at journals with less stringent policies were only very slightly higher than those with no policy at all. At one extreme, we found that mandated data archiving policies that require the inclusion of a data availability statement in the manuscript improve the odds of finding the data online almost a thousand fold compared to having no policy. However, archiving rates at journals with less stringent policies were only very slightly higher than those with no policy at all. We also assessed the effectiveness of asking for data directly from authors and obtained over half of the requested datasets, albeit with about 8 days delay and some disagreement with authors. Given the long term benefits of data accessibility to the academic community, we believe that journal based mandatory data archiving policies and mandatory data availability statements should be more widely adopted