Master of Science

thesisChapter 1 examines the stratigraphic architecture of the lower straight cliffs formation across the southwestern portion of the Kaiparowits Plateau in southern Utah. To determine the controls affecting deposition of marginal marine deposits, seven stratigraphic sections (each ~90-100m) and 729 paleocurrents were measured along a 20 km transect (A-A'). This study divides the lower Straight Cliffs Formation into four depositional units (DU), representing distinct and genetically-related depositional environments: prograding shoreface parasequences (DU-1), tidally influenced fluvial channels and estuaries (DU-2), a transitional sequence of shoreface deposits through fluvial deposits (DU-3), and downstream accreting fluvial deposits (DU-4). This interpretation represents both minor and more significant revisions to previous interpretations of this succession, and highlights the need for high-resolution stratigraphic studies to fully understand depositional compexity in this and similar settings. Earth scientists often use images to communicate scientific concepts, and they commonly provide cues establishing the scale of features shown ('hammer for scale,' etc). How effective are these kinds of scaling cues? Chapter 2 examines the effect of scaling cures and interactivity on the ability of earth scientists to extract information from 2 2D image. To evaluate both scaling cues and interactivity, a visualization test was created in which participants were asked to estimate the size of several boxes shown in outcrop photos. All test subjects first viewed a static image, followed by an interactive (gigapan) image of the same outcrop; two different outcrops of different sizes were used. Participants (test group =63, further testing in progress) represent a range of experience and education levels. Results show that scaling estimates are more difficult for larger/more distant outcrops. Scaling cues can also become a distractor for viewers of any experience level or background. It is important to realize that viewers internalize scaling cues differently, so different types of cues may help some viewers more than others. Also it appears that incorporating interactivity can increase accuracy, due to the ability to customize views that best fits an individual's learning style and internal sense of problem solving, The results of this study contain numerous educational implications for the application of scale and interactivity

Four rural cemeteries in central western NSW: Islands of Australiana in a European sea?

Vascular plants present in groundstoreys of variously–managed areas in four cemeteries in central western NSW – two on the Central Western Slopes (Garra and Toogong) and two on the Central Tablelands (Lyndhurst and Carcoar) – were recorded over periods of 6–10 years. It was hypothesised that (a) areas of the cemeteries with a history of nil or low disturbance would represent high quality remnant vegetation (i.e. contain a diversity of native species but few naturalised species), and (b) that clearing of woody vegetation, together with similar management (e.g. regular mowing) would result in homogenisation of the groundstoreys such that many species, native and naturalised, would be common to all sites. 344 species (176 native, 154 naturalised and 14 non–naturalised exotics) were recorded across the four cemeteries. Many native species that were rare in the surrounding agricultural lands were present in the cemeteries (enhancing their value as conservation areas) but no cemetery contained areas of groundstorey that would qualify as ‘pristine’. Across all management areas, the proportions of naturalised species in the native + naturalised floras of the cemeteries ranged from 46 to 55 %. Though never dominant, naturalised species also comprised high proportions (42 to 51 %) of the floras of the least disturbed (nil or infrequently mown) areas within each cemetery. Many (40 %) of the species recorded occurred at only one cemetery. This partly explained why the floras of similarly– managed parts of cemeteries on the Central Western Slopes were, contrary to expectations, markedly different to those on the Central Tablelands. However, within the same botanic subdivision, floras – particularly of naturalised species in regularly mown grasslands – were more similar (‘homogenised’) than those of nil or infrequently mown grasslands

Baseline study of employability related activities in Scottish colleges

In October 2004, the Scottish Funding Council (SFC)'s predecessor bodies, theSFEFC and the SHEFC, publishedLearning to Work(SFC 2004), a discussion paperabout how Scotland's colleges and universities can help to enhance learners'employability. In subsequent dialogue with stakeholders, there was agreement thatemployability should be a specific focus for quality enhancement in the college sectorfrom 2006-07. As a basis for further development, the SFC commissioned this studyto provide information on the range of current activities and practices in Scotland'scolleges which contribute to enhancing employability

Location Coding by Opponent Neural Populations in the Auditory Cortex

Although the auditory cortex plays a necessary role in sound localization, physiological investigations in the cortex reveal inhomogeneous sampling of auditory space that is difficult to reconcile with localization behavior under the assumption of local spatial coding. Most neurons respond maximally to sounds located far to the left or right side, with few neurons tuned to the frontal midline. Paradoxically, psychophysical studies show optimal spatial acuity across the frontal midline. In this paper, we revisit the problem of inhomogeneous spatial sampling in three fields of cat auditory cortex. In each field, we confirm that neural responses tend to be greatest for lateral positions, but show the greatest modulation for near-midline source locations. Moreover, identification of source locations based on cortical responses shows sharp discrimination of left from right but relatively inaccurate discrimination of locations within each half of space. Motivated by these findings, we explore an opponent-process theory in which sound-source locations are represented by differences in the activity of two broadly tuned channels formed by contra- and ipsilaterally preferring neurons. Finally, we demonstrate a simple model, based on spike-count differences across cortical populations, that provides bias-free, level-invariant localization—and thus also a solution to the “binding problem” of associating spatial information with other nonspatial attributes of sounds

Levels of house dust mite allergen in cars [Razine alergena prašinskih grinja u automobilima]

This small study investigated house dust mite (HDM) allergen levels in cars and their owners’ homes in north-east Scotland. Dust samples from twelve households and cars were collected in a standardised manner. The dust samples were extracted and measured for the Dermatophagoides group 2 allergens (Der p 2 and Der f 2) and total soluble protein. Allergen levels at homes tended to be higher than in the cars, but not significantly. However, they significantly correlated with paired car dust samples expressed either per unit weight of dust or soluble protein (rho=0.657; p=0.02 and 0.769; p=0.003, respectively). This points to house-to-car allergen transfer, with the car allergen levels largely reflecting levels in the owner’s home. Car HDM allergen levels were lower than those reported in Brazil and the USA. Twenty-five percent of the houses and none of the cars had allergen levels in dust greater than 2000 ng g-1. This value is often quoted as a threshold for the risk of sensitisation, although a number of studies report increased risk of sensitisation at lower levels. This small study does not allow for characterisation of the distribution of HDM allergen in vehicles in this geographic area, or of the likely levels in other warmer and more humid areas of the UK. Cars and other vehicles are an under-investigated micro-environment for exposure to allergenic material. U ovome smo preliminarnom istraživanju izmjerili razine alergena prašinskih grinja u automobilima i domovima njihovih vlasnika u sjevernoistočnoj Škotskoj. Uzorci prašine uzeti su na standardizirani način iz dvanaest domova i dvanaest odgovarajućih automobila. Nakon ekstrakcije izmjerene su razine 2. skupine alergena grinja roda Dermatophagoides (Der p 2 i Der f 2) te njihove ukupne topljive bjelančevine. Razine alergena u kućama bile su mahom više nego u automobilima, ali ne značajno. Uočena je međutim značajna korelacija njihovih razina s razinama u automobilima, bez obzira na to jesu li iskazane udjelom težine po gramu prašine ili topljivim bjelančevinama (rho=0,657; p=0,02 odnosno 0,769; p=0,003). To upućuje na prijenos alergena iz kuće u auto tj. pokazuje da razine alergena u autima odražavaju razine u domovima njihovih vlasnika. Razine alergena kućnih prašinskih grinja u automobilima u Škotskoj bile su niže od onih izmjerenih u Brazilu i SAD-u. U 25 % domova razina alergena bila je viša od 2000 ng g-1, a ni u jednom uzorku nije izmjerena razina viša od te. Ta se vrijednost često smatra graničnom za rizik od senzitizacije, premda neka istraživanja govore o povišenom riziku od senzitizacije i pri nižim razinama alergena. Rezultati ovog istraživanja ne daju uvida u stvarnu prisutnost alergena kućnih prašinskih grinja u vozilima u sjeveroistočnoj Škotskoj niti upućuju na to kolike bi mogle biti njihove razine u toplijim i vlažnijim krajevima Ujedinjenog Kraljevstva. Automobili i ostala vozila zanemareni su kao izvori izloženosti alergenima

Sestrins are evolutionarily conserved mediators of exercise benefits.

Exercise is among the most effective interventions for age-associated mobility decline and metabolic dysregulation. Although long-term endurance exercise promotes insulin sensitivity and expands respiratory capacity, genetic components and pathways mediating the metabolic benefits of exercise have remained elusive. Here, we show that Sestrins, a family of evolutionarily conserved exercise-inducible proteins, are critical mediators of exercise benefits. In both fly and mouse models, genetic ablation of Sestrins prevents organisms from acquiring metabolic benefits of exercise and improving their endurance through training. Conversely, Sestrin upregulation mimics both molecular and physiological effects of exercise, suggesting that it could be a major effector of exercise metabolism. Among the various targets modulated by Sestrin in response to exercise, AKT and PGC1α are critical for the Sestrin effects in extending endurance. These results indicate that Sestrin is a key integrating factor that drives the benefits of chronic exercise to metabolism and physical endurance

Enhanced negative type for finite metric trees

Finite metric trees are known to have strict 1-negative type. In this paper we introduce a new family of inequalities that quantify the extent of the "strictness" of the 1-negative type inequalities for finite metric trees. These inequalities of "enhanced 1-negative type" are sufficiently strong to imply that any given finite metric tree must have strict p-negative type for all values of p in an open interval that contains the number 1. Moreover, these open intervals can be characterized purely in terms of the unordered distribution of edge weights that determine the path metric on the particular tree, and are therefore largely independent of the tree's internal geometry. From these calculations we are able to extract a new non linear technique for improving lower bounds on the maximal p-negative type of certain finite metric spaces. Some pathological examples are also considered in order to stress certain technical points.Comment: 35 pages, no figures. This is the final version of this paper sans diagrams. Please note the corrected statement of Theorem 4.16 (and hence inequality (1)). A scaling factor was omitted in Version #

p53 regulates mitochondrial dynamics in vascular smooth muscle cell calcification.

Arterial calcification is an important characteristic of cardiovascular disease. It has key parallels with skeletal mineralization; however, the underlying cellular mechanisms responsible are not fully understood. Mitochondrial dynamics regulate both bone and vascular function. In this study, we therefore examined mitochondrial function in vascular smooth muscle cell (VSMC) calcification. Phosphate (Pi)-induced VSMC calcification was associated with elongated mitochondria (1.6-fold increase, p p p p p p p p p p p p p p < 0.001) was also observed upon p53 knockdown in calcifying VSMCs. In summary, we demonstrate that VSMC calcification promotes notable mitochondrial elongation and cellular senescence via DRP1 phosphorylation. Furthermore, our work indicates that p53-induced mitochondrial fusion underpins cellular senescence by reducing mitochondrial function