Shoulder posture and median nerve sliding

Background: Patients with upper limb pain often have a slumped sitting position and poorshoulder posture. Pain could be due to poor posture causing mechanical changes (stretch; localpressure) that in turn affect the function of major limb nerves (e.g. median nerve). This studyexamines (1) whether the individual components of slumped sitting (forward head position, trunkflexion and shoulder protraction) cause median nerve stretch and (2) whether shoulderprotraction restricts normal nerve movements.Methods: Longitudinal nerve movement was measured using frame-by-frame cross-correlationanalysis from high frequency ultrasound images during individual components of slumped sitting.The effects of protraction on nerve movement through the shoulder region were investigated byexamining nerve movement in the arm in response to contralateral neck side flexion.Results: Neither moving the head forward or trunk flexion caused significant movement of themedian nerve. In contrast, 4.3 mm of movement, adding 0.7% strain, occurred in the forearm duringshoulder protraction. A delay in movement at the start of protraction and straightening of thenerve trunk provided evidence of unloading with the shoulder flexed and elbow extended and thescapulothoracic joint in neutral. There was a 60% reduction in nerve movement in the arm duringcontralateral neck side flexion when the shoulder was protracted compared to scapulothoracicneutral.Conclusion: Slumped sitting is unlikely to increase nerve strain sufficient to cause changes tonerve function. However, shoulder protraction may place the median nerve at risk of injury, sincenerve movement is reduced through the shoulder region when the shoulder is protracted andother joints are moved. Both altered nerve dynamics in response to moving other joints and localchanges to blood supply may adversely affect nerve function and increase the risk of developingupper quadrant pain

A universal relationship between magnetization and local structure changes below the ferromagnetic transition in La_{1-x}Ca_xMnO_3; evidence for magnetic dimers

We present extensive X-ray Absorption Fine Structure (XAFS) measurements on La_{1-x}Ca_xMnO_3 as a function of B-field (to 11T) and Ca concentration, x (21-45%). These results reveal local structure changes (associated with polaron formation) that depend only on the magnetization for a given sample, irrespective of whether the magnetization is achieved through a decrease in temperature or an applied magnetic field. Furthermore, the relationship between local structure and magnetization depends on the hole doping. A model is proposed in which a filamentary magnetization initially develops via the aggregation of pairs of Mn atoms involving a hole and an electron site. These pairs have little distortion and it is likely that they pre-form at temperatures above T_c.Comment: 5 pages, 5 figures (1 with 2 parts) -- v2. new data added (updated figures); discussion expande

Gynaecological surveillance in high risk women

Increasing availability of genetic testing and falling costs of the tests suggests that growing numbers of unaffected women will be identified worldwide who are at increased risk of gynaecological malignancies. The challenge in those identified is to prevent and detect the disease early without causing significant harm. Currently surgery remains the cornerstone of management. Most women undergoing surgery do not report a significant deterioration of their physical and mental health-related quality of life (1). However the resulting premature menopause is associated with decrease in sexual functioning and vasomotor symptoms even in women on hormone replacement therapy (HRT)(2)(3). As a result there is a continued effort to develop effective screening strategies for high risk women

The effects of a dietary supplement of fresh oranges on the oral health of children

Indiana University-Purdue University Indianapolis (IUPUI)The effects of additional citrus fruit in the diet on the periodontium have been a debated subject for some time. This study attempted to measure the effects of eating three additional oranges per day by 123 children ages six through twenty years and an equal number of controls over a 23-week period. To measure any changes that might take place, the following were evaluated clinically, and the decayed, missing and filled surfaces were also evaluated radiographically: 1. gingival status 2. plaque formation 3. D.M.F.S. and d.m.f.s. 4. white spots Results after the 23 week test period showed that the gingival scores increased significantly in both groups (increased inflammation). The plaque formation score also increased in both groups, but only the non-orange eaters' score increased significantly over their original score and over the orange eaters' score. The decayed, missing, and filled surfaces and white spots did not change significantly in either group. Therefore with this study sample over the 23-week test period, the additional oranges in the diet had limited measurable effect on the hard and soft tissues of the oral cavity

The effects of introduced mice on seabirds breeding at sub-Antarctic Islands

Seabirds play keystone roles as apex predators in marine ecosystems and also influence the ecology of terrestrial ecosystems where they breed. Seabirds are among the most threatened group of birds - almost half of all seabird species are known or suspected to be experiencing population declines with 97 (28%) of the 346 species currently classed as globally threatened and at risk of extinction. Introduced predators at oceanic islands where many seabirds breed account for the largest proportion of population declines, more so than incidental fisheries bycatch or degradation of their breeding habitats. Since few oceanic islands have escaped invasion, the problem is widespread, with the prime culprits being introduced cats Felis catus, rats Rattus spp. and house mice Mus musculus which depredate adult birds, chicks and eggs. Rats were widely introduced to thousands of islands and their catastrophic effects on seabird populations have been well documented. Mice are estimated to have invaded more oceanic islands than any other alien predator, but until fairly recently they were considered to have little impact on seabird populations. This thesis focuses on seabirds breeding at two large oceanic islands - Marion Island (293 km2 ) in the south Indian Ocean and Gough Island (65 km2 ) in the south central Atlantic Ocean. Both islands have mice as the sole introduced mammal. Of relevance to this study, however, is that the density of burrow-nesting petrels is much higher on Gough Island because Marion Island’s petrel populations were greatly reduced by cats, which were introduced in 1948 and eradicated by 1991. In the early 2000s, researchers on Gough Island identified mouse predation as the most probable cause of the high chick mortality of at least three species of seabirds, including the endemic Tristan albatross Diomedea dabbenena. Further research concluded that mice can be devastating predators of seabirds on islands where they are the sole introduced mammal, because in the absence of competition and predation from larger introduced species, mice can attain very high population densities, and resort to attacking seabird chicks mainly in winter when there are few other food sources. In 2003, the first mouse-injured wandering albatross Diomedea exulans chicks were found on Marion Island and in 2009 the first attacks on summer-breeding albatross chicks were recorded, but incidents appeared to be infrequent. Although mouse predation had been identified as a potentially serious threat to seabirds at both islands, further evidence was required on how many seabird species were being affected and to quantify the impacts. Field observations suggested a noticeable increase in levels of mouse predation at both islands, yet there was still no direct evidence of mice depredating burrow-nesting petrels at Marion. In this thesis I assess the impacts of invasive mice at both islands and establish pre-eradication baseline estimates for the burrow-nesting petrel populations at Marion Island. Burrow-nesting petrels are the most abundant seabirds in the Southern Ocean, yet their populations are poorly known compared to surface-breeding albatrosses because they are difficult to survey accurately. Extrapolation from density estimates can lead to large error margins, but these can be reduced with the development of repeatable, island-specific survey methods for long-term monitoring. This forms the basis of Chapter 2, where I test the effect of sampling strategy (random transect or systematic survey) on population size estimates of three burrow-nesting petrel populations at Marion Island. Systematic, island-wide surveys were appropriate to estimate the population sizes of blue petrels Halobaena caerulea (strongly clustered distribution - Appendix 1) and white-chinned petrels Procellaria aequinoctialis (moderately clustered distribution - Appendix 2) and but for the very widely distributed great-winged petrels Pterodroma macroptera I counted burrows within random transects and extrapolated burrow densities by associated habitat attributes to generate island-wide estimates. The systematic surveys required more effort, but resulted in more accurate estimates for species with clustered distributions, whereas the random transects required less effort but resulted in broad estimates with wide error margins which limits the ability to detect changes over time. In Chapter 3, I investigate how burrow-nesting petrel populations on Marion Island have recovered since cats were eradicated in 1991. In theory, the removal of cats as the superpredator, combined with endogenous growth and the potential for immigration from nearby mouse-free Prince Edward Island, could have promoted a multi-fold increase in petrel numbers over the last two decades. To investigate this, I repeated a burrow-nesting petrel survey in the north-eastern sector of Marion Island originally conducted by Mike Schramm in 1979 and assessed how burrow densities have changed compared to densities at the peak of the cat-era. I found that burrow densities have increased by a modest 56% since 1979. The recovery of summer-breeding petrels decreased with decreasing body size, and winterbreeding species showed even smaller recoveries, which is similar to patterns of breeding success at Gough Island where mice are the major drivers of population declines among petrels. Mice are the likely cause of the limited recovery of burrowing petrels at Marion Island. To assess and document the impacts of invasive mice at both islands, I installed infra-red video cameras into burrows and assessed breeding success with regular burrow-scope nest inspections of study colony nests at both Gough and Marion Islands (Chapters 4 and 5). The results show that mice can be very effective predators of burrow-nesting petrel chicks and to a lesser extent, eggs. The breeding success for winter breeders were lower than for summer breeders at both islands, and among winter breeders most chick fatalities were of small chicks less than 14 days old. Fatal mouse attacks on small chicks were video recorded for six burrow-nesting petrel species and winter breeders had very high chick mortality rates (e.g. 82–100% on Gough Island). Since mouse depredation of seabird chicks was first identified as a problem in 2001, the frequency and severity of mouse predations appears to have escalated on Gough (Appendix 3), yet on Marion Island detected incidents remained infrequent until 2015, when mice attacked 4.0–4.6% of the large chicks of all three albatross species that fledge in autumn. Attacks started independently in small pockets all around the island’s 70 km coastline, separated by distances hundreds of times greater than mouse home ranges. Attacks have continued from 2016–2018 at varying rates on summer-breeding albatross fledglings, showing how mice alone may significantly affect threatened seabird species (Chapter 6). In summary, mice appear to be suppressing the productivity of burrow- and surface-nesting seabird populations at both islands and are very likely causing population declines, especially among winter breeding species. Fortunately, the removal of invasive mice from islands through aerial spreading of toxic bait is a viable option and the scientific and visual evidence collected during this thesis has contributed to the growing body of evidence needed to persuade funders and Governments to support eradication operations at both study islands

Observation of ferromagnetism above 900 K in Cr-GaN and Cr-AlN

We report the observation of ferromagnetism at over 900K in Cr-GaN and Cr-AlN thin films. The saturation magnetization moments in our best films of Cr-GaN and Cr-AlN at low temperatures are 0.42 and 0.6 u_B/Cr atom, respectively, indicating that 14% and 20%, of the Cr atoms, respectively, are magnetically active. While Cr-AlN is highly resistive, Cr-GaN exhibits thermally activated conduction that follows the exponential law expected for variable range hopping between localized states. Hall measurements on a Cr-GaN sample indicate a mobility of 0.06 cm^2/V.s, which falls in the range characteristic of hopping conduction, and a free carrier density (1.4E20/cm^3), which is similar in magnitude to the measured magnetically-active Cr concentration (4.9E19/cm^3). A large negative magnetoresistance is attributed to scattering from loose spins associated with non-ferromagnetic impurities. The results indicate that ferromagnetism in Cr-GaN and Cr-AlN can be attributed to the double exchange mechanism as a result of hopping between near-midgap substitutional Cr impurity bands.Comment: 14 pages, 4 figures, submitted to AP