Relating Noncommutative SO(2,3) Gravity to the Lorentz-Violating Standard-Model Extension

We consider a model of noncommutative gravity that is based on a spacetime with broken local SO(2,3) symmetry. We show that the torsion-free version of this model is contained within the framework of the Lorentz-violating Standard-Model Extension. We analyze in detail the relation between the torsion-free, quadratic limits of the broken SO(2,3) model and the Standard-Model Extension. As part of the analysis,we construct the relevant geometric quantities to quadratic order in the metric perturbation around a flat background.Comment: 10 pages, accepted in Symmetr

Protecting the Art of Leningrad: The Survival of the Hermitage Museum during the Great Patriotic War

The Hermitage Museum rises from the banks of the Neva River in the center of St. Petersburg, the former capital of Russia. The complex, existing of five buildings constructed over a period of about two hundred years, houses one of the greatest art collections in the world. Although the Hermitage is best known for its collection of great paintings, including works by Leonardo, Raphael, Rembrandt, and Picasso, the museum also holds great archeological exhibits. Scholars from throughout the world conduct research in the extensive Numismatics Department, the Gothic Library, and the Department of Far Eastern Culture. ... Throughout its history, the museum staff evacuated the collections of the Hermitage three times. The first occurred in 1812 as Napoleon was invading Russia and the second took place during World War I. In retrospect, neither of these evacuations proved to be necessary, the invading armies did not advance no St. Petersburg. The third evacuation, however, probably saved the collections from great damage. This evacuation took place in June and July, 1941. Nazi Germany invaded Russia in June of that year and its armies had surrounded St. Petersburg, then called Leningrad, by early September. Hitler\u27s forces laid siege to Leningrad for almost nine hundred days. Throughout the blockade, German artillery units indiscriminately fired shells into the city; thirty of these shells hit the Hermitage museum. The siege put the Hermitage and its staff under great strain. Although most of the great paintings were evacuated, many of the collections remained. Two freight trains carrying art items escaped Leningrad, a third was being loaded when the Germans cut off the last remaining rail line. The director of the museum, Joseph Orbeli, and his staff had to make numerous decisions on how to best preserve what remained in the Hermitage and how to protect the buildings of the museum complex. To exacerbate the problems, more than two thousand Leningraders, mostly from the academic and cultural community, made their home in the basement of the Hermitage throughout the blockade. Some of the orders handed down from Orbeli and his staff were minor, such as where to store certain art items or how best to clean antique furniture stained by water leaking from frozen pipes. Others, such as Orbeli\u27s decision to prepare for the evacuation despite a lack of orders from Moscow, were more memorable. The Hermitage ultimately survived the siege, but not without damage. The staff living in the basements of the museum were responsible for the protection of the buildings and their content. It might be argued that, in light of the terrible plight of the city under siege, the staff deserves nothing other than praise for its actions -- the Hermitage stands today, with great collections and worldwide reputation. On the other hand, much was lost. Precious items of artistic and historic significance are gone forever due to German artillery shelling. Moreover, the Hermitage buildings suffered from neglect during the siege. One could claim that some of the damage was preventable. These arguments might be resolved through a detailed analysis of the decisions made during the siege by Orbeli and his staff

The Mechanisms of Posterior Shoulder Tightness and Effectiveness of Manual Therapy

Posterior shoulder tightness is a common physical impairment in overhand baseball athletes presenting with injury. The etiology of this physical impairment is poorly understood and theorized to be a combination of bony, muscular, and inert soft-tissue contributions occurring at the glenohumeral joint. The ability to discriminate between each tissue\u27s influences on shoulder range of motion is often challenging to overcome within a clinical environment. Chapter 2 of this manuscript provides a thorough review of the literature discussing the potential mechanisms of posterior shoulder tightness. Previous studies have independently accounted for the relationships between posterior shoulder tightness, and the mechanical contributions of bony anatomy and capsuloligamentous stability. Chapter 3 of this dissertation research is a clinical commentary that discusses the current uses of rehabilitative shoulder ultrasound imaging including specific functions to account for the theorized mechanisms of posterior shoulder tightness. DISS_para\u3eIn overhead throwing athletes, the range of motion deficits of posterior shoulder tightness have been linked to increased prospective injury risk. Therapeutic treatment interventions have shown a promising ability to improve some of these motion deficits although programs are often not tailored to target specific tissues. Chapter 4 is a randomized controlled trial comparing the acute treatment effectiveness of a muscle-directed manual therapy intervention and posterior shoulder stretching routine versus stretching alone. The results indicate that the added use of muscle-directed manual therapy significantly enhances the amount of ROM gained when compared to stretching alone. These clinical data suggest that musculotendinous stiffness influences the deficits associated with posterior shoulder tightness. In Chapter 5, we specifically examine the local physiologic contributions of humeral morphology, glenohumeral joint translation, and rotator cuff stiffness with the resolution of posterior shoulder tightness. Of these potential mechanisms, rotator cuff stiffness was the only tissue responsive to the application of muscle-directed manual therapy. Furthermore, the decreases observed in muscle stiffness were concurrent with the supplemental gains in shoulder ROM. These findings indicate that manual therapy treatment directly applied to the rotator cuff is effective at decreasing muscle stiffness and reducing deficits in posterior shoulder tightness. The results of this dissertation research suggest that rotator cuff stiffness is partially responsible for the presence of posterior shoulder tightness and that muscle-directed manual therapy is effective at decreasing dominant sided deficits in shoulder ROM. Further research is required to determine the potential long-term effects of muscle-directed manual and stretching for the injury prevention and treatment of athletes with posterior shoulder tightness

Secondary Content Teachers\u27 Perceptions of Instructing English for Speakers of Other Languages (ESOL) Students: A Phenomenological Study

The purpose of this phenomenological study was to describe the lived experiences of secondary content teachers who instruct English Language Learner (ELL) students. ELLs are the fastest growing population of students in the United States. As this group continues to grow, so do the challenges of providing equitable education. Although most schools have adopted one or more models of instruction for ELLs, there is no universal model. High stakes testing and improved college readiness curriculum are designed to provide higher expectations for student achievement. However, ELL students continue to fall behind their native English-speaking peers in math and reading. Secondary content teachers should be knowledgeable of the unique needs of ELLs and feel supported when teaching these students. Understanding the lived experiences and perceptions of teachers who instruct ELL students at the secondary content level can lead to a positive and successful learning environment for the students and the teachers. Participants included 12 secondary content teachers from three high schools in a southern state. I utilized one-on-one interviews, focus group interviews, and participant journaling from all participants to gather data about what the participants experienced and how they experienced it. The theories guiding this study were Krashen’s 1982 theory of second language acquisition and Cummins’ 1980 theory of language development as both have been instrumental in developing models of instruction and strategies to instruct ELL students and continue to play an integral role in today’s instructional methods

Severe Withdrawal Syndrome Possibly Associated With Cessation of a Midazolam and Fentanyl Infusion

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90212/1/j.1875-9114.1995.tb02877.x.pd

Gravitational physics with antimatter

The production of low-energy antimatter provides unique opportunities to search for new physics in an unexplored regime. Testing gravitational interactions with antimatter is one such opportunity. Here a scenario based on Lorentz and CPT violation in the Standard- Model Extension is considered in which anomalous gravitational effects in antimatter could arise.Comment: 5 pages, presented at the International Conference on Exotic Atoms (EXA 2008) and the 9th International Conference on Low Energy Antiproton Physics (LEAP 2008), Vienna, Austria, September 200

Lorentz Violation and the Yukawa Potential

We analyze Lorentz violations in the bosonic sector of a Yukawa-type quantum field theory. The nonrelativistic potential may be determined to all orders in the Lorentz violation, and we find that only specific types of modifications to the normal Yukawa potential can be generated. The influence of this modified potential on scattering and bounds states is calculated. These results could be relevant to the search for new macroscopic forces, which may not necessarily be Lorentz invariant.Comment: 10 page

Educational games as a motivational tool: Considerations on their potential and limitations

There is considerable interest in leveraging video games to support students’ motivation. This involves employment of educational (serious) and entertainment games. However, while evidence indicates that games can enhance learning outcomes, doubts persist about whether they retain their enjoyable character in formal learning contexts. This study was carried out within the H2020 Gaming Horizons project, which involved a review of academic literature on the role of games in society, as well as 73 semi-structured interviews with relevant stakeholders, including players and educators, investigating their positions on game-related issues. The interviews suggested that players tend to view game-based learning – and specifically serious games at school – with scepticism. This is partly attributable to the perception that serious games have lower production values than entertainment games, and that gaming, as a voluntary, self-driven activity, clashes with the structured nature of school. Some educators reported individual and gender differences in the motivating power of games. However, the use of entertainment games to foster learning outcomes was seen favourably. Two focus groups devoted to the issue highlighted the need for carefully tailoring the gaming experience to both context and student, and the importance of developing a sustainable business model for enhancing serious games quality

Relating Noncommutative SO(2,3)* Gravity to the Lorentz-Violating Standard-Model Extension

We consider a model of noncommutative gravity that is based on a spacetime with broken local SO(2,3)* symmetry. We show that the torsion-free version of this model is contained within the framework of the Lorentz-violating Standard-Model Extension (SME). We analyze in detail the relation between the torsion-free, quadratic limits of the broken SO(2,3)* model and the Standard-Model Extension. As part of the analysis, we construct the relevant geometric quantities to quadratic order in the metric perturbation around a flat background

CPT and Lorentz tests with muons

Precision experiments with muons are sensitive to Planck-scale CPT and Lorentz violation that is undetectable in other tests. Existing data on the muonium ground-state hyperfine structure and on the muon anomalous magnetic moment could be analyzed to provide dimensionless figures of merit for CPT and Lorentz violation at the levels of $4\times 10^{-21}$ and $10^{-23}$.Comment: 4 pages, accepted for publication in Physical Review Letter