Trophic downgrading of ecosystems necessitates a functional understanding of trophic cascades. Identifying the presence of cascades, and the mechanisms through which they occur, is particularly important for seagrass meadows, which are among the most threatened ecosystems on Earth. Shark Bay, Western Australia provides a model system to investigate the potential importance of top-down effects in a relatively pristine seagrass ecosystem. The role of megagrazers in the Shark Bay system has been previously investigated, but the role of macrograzers (i.e., teleosts), and their importance relative to megagrazers, remains unknown. The objective of my dissertation was to elucidate the importance of teleost macrograzers in transmitting top-down effects in seagrass ecosystems. Seagrasses and macroalgae were the main food of the abundant teleost Pelates octolineatus, but stable isotopic values suggested that algae may contribute a larger portion of assimilated food than suggested by gut contents. Pelates octolineatus is at risk from numerous predators, with pied cormorants (Phalacrocorax varius) taking the majority of tethered P. octolineatus. Using a combination of fish trapping and unbaited underwater video surveillance, I found that the relative abundance of P. octolineatus was greater in interior areas of seagrass banks during the cold season, and that the mean length of P. octolineatus was greater in these areas compared to along edges of banks. Finally, I used seagrass transplants and exclosure experiments to determine the relative effect of megagrazers and macrograzers on the establishment and persistence of three species of seagrasses in interior microhabitats. Teleost grazing had the largest impact on seagrass species with the highest nutrient content, and these impacts were primarily observed during the warm season. My findings are consistent with predictions of a behaviorally-mediated trophic cascade initiated by tiger sharks (Galeocerdo cuvier) and transmitted through herbivorous fishes and their predators.

As climate change continues, climactic extremes are predicted to become more frequent and intense, in some cases resulting in dramatic changes to ecosystems. The effects of climate change on ecosystems will be mediated, in part, by biotic interactions in those ecosystems. However, there is still considerable uncertainty about where and how such biotic interactions will be important in the context of ecosystem disturbance and climactic extremes. Here, I review the role of consumers in seagrass ecosystems and investigate the ecological impacts of an extreme climactic event (marine heat wave) and subsequent widespread seagrass die-off in Shark Bay, Western Australia. Specifically, I compare seagrass cover, shark catch rates, and encounter rates of air breathing fauna in multiple habitat types before and after the seagrass die-off to describe post-disturbance dynamics of the seagrass community, shifts in consumer abundances, and changes in risk-sensitive habitat use patterns by a variety of mesoconsumers at risk of predation from tiger sharks (Galeocerdo cuvier). Finally, I conducted a 16 month field experiment to assess whether xi loss of top predators, and predicted shifts in dugong foraging, could destabilize remaining seagrass. I found that the previously dominant temperate seagrass Amphibolis antarctica is stable, but not increasing. Conversely, an early-successional tropical seagrass, Halodule uninervis, is expanding. Following the die-off, the densities of several consumer species (cormorants, green turtles, sea snakes, and dugongs) declined, while others (Indo-Pacific bottlenose dolphins, loggerhead sea turtles, tiger sharks) remained stable. Stable tiger shark abundances following the seagrass die-off suggest that the seascape of fear remains intact in this system. However, several consumers (dolphins, cormorants) began to use dangerous but profitable seagrass banks more often following seagrass decline, suggesting a relaxation of anti-predator behavior. Experimental results suggest that a loss of tiger sharks would result in a behaviorally mediated trophic cascade (BMTC) in degraded seagrass beds, further destabilizing them and potentially resulting in a phase shift. My work shows that climactic extremes can have strong but variable impacts on ecosystems mediated in part by species identity, and that maintenance of top predator populations may by important to ecological resilience in the face of climate change.

THIS THESIS IS IN THE EXAMINATION PROCESS The ability to locate symbols on a visual display forms an integral part of the effective use of AAC systems. Characteristics of display design and perceptual features of symbols have been shown to influence rate and accuracy of symbol location (Thistle&Wilkinson, 2009; Wilkinson, Carlin,&Jagaroo, 2006). The current study endeavoured to compare the use of two colour-coded organisational strategies (alphabetical order and subcategorisation) for their effectiveness in symbol location and to investigate if some bottom-up features influenced the performance of the participants in these tasks. 114 learners in Grade 1 to 3 in a mainstream school were randomly divided into two groups. Both of the groups were exposed to two visual search tests in alternating order. The tests involved searching for 36 visual targets amongst 81 coloured Picture Communication Symbols on a computer screen in one of two colour-coded organizational methods, namely alphabetical order or subcategorisation. The data from the research task was collected through computer logging of all mouse selections. Findings showed that locating symbols on a computer screen with a subcategorisation strategy was significantly faster and more accurate than with an alphabetical strategy for the Grade 1 to 3 participants. The differences between the rates and accuracy of target symbol location using the two strategies decreased significantly as grade increased. It was also found that although the tests in this study placed heavy top-down processing demands on the participants, there was still evidence of bottom-up factors influencing their performance. Implications for display design in AAC clinical practice were discussed. / Thesis (PhD)--University of Pretoria, 2012. / Centre for Augmentative and Alternative Communication (CAAC) / Unrestricted

A case study has been conducted in a municipal child and educationadministration. The aim was to develop a management system for thesystematic quality work at an overall level and identify what isimportant to think about to make the system work in theorganization. The studied organization has low student results and alarge proportion of the students do not gain admission to the uppersecondary school. The study is based on theories of systematicquality work and laws within the school and theories about offensivequality development. Surveys, interviews, document reviews, processmapping and literature studies have been used in the study. Theprocess mapping shows that the current systematic quality work has atop-down perspective. The results of surveys, interviews anddocument review indicate that there is a lack of commitment at theunit level. The current systematic quality work doesn´t lead to anydevelopment, partly because the follow-ups and analyzes, that arecarried out in the units, do not constitute a sufficient basis forthe top management to prioritize what is needed to do to develop thebusiness. The current top-down perspective is challenged and abottom-up perspective is proposed to gain greater involvement andparticipation. A new process, a management system as well as aproposal for implementation is suggested for the organization. Themanagement system is based on total quality management (TQM). / En fallstudie har genomförts i en kommunal barn- och utbildningsförvaltning i syfte att ta fram ett ledningssystem för det systematiska kvalitetsarbetet på en övergripande nivå och identifiera vad som är viktigt att tänka på för att få systemet att fungera i organisationen. Den studerade organisationen har låga elevresultat och en stor andel av eleverna uppnår inte behörighet till gymnasiet. Studien baseras på teorier och lagstiftning om systematiskt kvalitetsarbete inom skolan och teorier om offensiv kvalitetsutveckling. Enkäter, intervjuer, dokumentgranskningar, processkartläggning och litteraturstudier har använts i studien. Processkartläggningen visar att det nuvarande systematiska kvalitetsarbetet har ett top-downperspektiv och resultatet av enkäter, intervjuer och dokumentgranskningen tyder på att det finns ett bristande engagemang på enhetsnivå. Det nuvarande systematiska kvalitetsarbetet medför inte att verksamheterna utvecklas, bland annat beroende på att de uppföljningar och utvärderingar som genomförs på enheterna inte utgör ett tillräckligt underlag för att huvudmannen skall kunna prioritera insatser som leder till att verksamheten utvecklas. Det nuvarande top-down-perspektivet ifrågasätts och ett bottom-up-perspektiv föreslås för att få ett större engagemang och delaktighet på enhetsnivå. Ett förslag på ny process, ett ledningssystem baserat på offensiv kvalitetsutveckling samt ett implementeringsförslag redovisas i studien.

<div>The visual system is responsible for processing visual input, inferring its environmental causes, and assessing its behavioral significance that eventually relates to visual perception and guides animal behavior. There is emerging evidence that visual perception does not simply mirror the outside world but is heavily influenced by contextual information. Specifically, context might refer to the sensory, cognitive, and/or behavioral cues that help to assess the behavioral relevance of image features. One of the most famous examples of such behavior is visual or optical illusions. These illusions contain sensory cues that induce a subjective percept that is not aligned with the physical nature of the stimulation, which, in turn, suggests that a visual system is not a passive filter of the outside world but rather an active inference machine.</div><div>Such robust behavior of the visual system is achieved through intricate neural computations spanning several brain regions that allow dynamic visual processing. Despite the numerous attempts to gain insight into those computations, it has been challenging to decipher the circuit-level implementation of contextual processing due to technological limitations. These questions are of great importance not only for basic research purposes but also for gaining deeper insight into neurodevelopmental disorders that are characterized by altered sensory experiences. Recent advances in genetic engineering and neurotechnology made the mouse an attractive model to study the visual system and enabled other researchers and us to gain unprecedented cellular and circuit-level insights into neural mechanisms underlying contextual processing.</div><div>We first investigated how familiarity modifies the neural representation of stimuli in the mouse primary visual cortex (V1). Using silicon probe recordings and pupillometry, we probed neural activity in naive mice and after animals were exposed to the same stimulus over the course of several days. We have discovered that familiar stimuli evoke low-frequency oscillations in V1. Importantly, those oscillations were specific to the spatial frequency content of the familiar stimulus. To further validate our findings, we investigated how this novel form of visual learning is represented in serotonin-transporter (SERT) deficient mice. These transgenic animals have been previously found to have various neurophysiological alterations. We found that SERT-deficient animals showed longer oscillatory spiking activity and impaired cortical tuning after visual learning. Taken together, we discovered a novel phenomenon of familiarity-evoked oscillations in V1 and utilized it to reveal altered perceptual learning in SERT-deficient mice.</div><div>16</div><div>Next, we investigated how spatial context influences sensory processing. Visual illusions provide a great opportunity to investigate spatial contextual modulation in early visual areas. Leveraging behavioral training, high-density silicon probe recordings, and optogenetics, we provided evidence for an interplay of feedforward and feedback pathways during illusory processing in V1. We first designed an operant behavioral task to investigate illusory perception in mice. Kanizsa illusory contours paradigm was then adapted from primate studies to mouse V1 to elucidate neural correlates of illusory responses in V1. These experiments provided behavioral and neurophysiological evidence for illusory perception in mice. Using optogenetics, we then showed that suppression of the lateromedial area inhibits illusory responses in mouse V1. Taken together, we demonstrated illusory responses in mice and their dependence on the top-down feedback from higher-order visual areas.</div><div>Finally, we investigated how temporal context modulates neural responses by combining silicon probe recordings and a novel visual oddball paradigm that utilizes spatial frequency filtered stimuli. Our work extended prior oddball studies by investigating how adaptation and novelty processing depends on the tuning properties of neurons and their laminar position. Furthermore, given that reduced adaptation and sensory hypersensitivity are one of the hallmarks of altered sensory experiences in autism, we investigated the effects of temporal context on visual processing in V1 of a mouse model of fragile X syndrome (FX), a leading monogenetic cause of autism. We first showed that adaptation was modulated by tuning properties of neurons in both genotypes, however, it was more confined to neurons preferring the adapted feature in FX mice. Oddball responses, on the other hand, were modulated by the laminar position of the neurons in WT with the strongest novelty responses in superficial layers, however, they were uniformly distributed across the cortical column in FX animals. Lastly, we observed differential processing of omission responses in FX vs. WT mice. Overall, our findings suggest that reduced adaptation and increased oddball processing might contribute to altered perceptual experiences in FX and autism.</div>

Killer whales are the oceans’ apex predator and are known to have important effects on ecosystems. At Subantarctic Marion Island, southern Indian Ocean, they have only been studied opportunistically, resulting in limited knowledge of their ecosystem impact here. This dissertation describes the prey and seasonal abundance, estimates the population size and assesses the predatory impact of killer whales on seals and penguins at Marion Island, using dedicated and opportunistic shore-based observations and photographic identification, from 2006 to 2009. During 823 sightings of killer whales at Marion Island (2006 to 2009) 48 predation events were recorded; in only 10 cases could prey be identified. Killer whales fed on fur seals, elephant seals and penguins. Constant effort (dedicated) observations (259 hours, 2008 to 2009) showed that killer whale abundance, which peaked in September to December with a secondary peak in April to May, is linked to the abundance of seals and penguins. Mark-recapture analyses were performed using nearly 10 000 photographs taken from 2006 to 2009. Following careful quality control criteria 37 individuals were identified and a population size of 42 (95% CI = 35-50) individuals estimated using the open population POPAN parameterization in the software program MARK. The analytical approach is more rigorous than that used in any previous population size assessment at Marion Island. Finally, the above data were integrated to assess whether top-down control of seal and penguin populations at Marion Island is generally plausible using a simple process of elimination. Based on published data I predicted the energetic ingestion requirements of adult male and female killer whales as 1 394 MJ.day-1 and 1 028 MJ.day-1, respectively. Expanding these requirements to the 37 killer whales photographically identified at Marion Island, the population requires 40 600MJ.day-1. Based on available energy density and mass data, I predicted the energy content of available seal and penguin prey and calculated the rates at which killer whales would consume these prey in various scenarios. Penguins and Subantarctic fur seals are relatively insensitive to killer whale predation owing to their large population sizes (10 000s to 100 000s), conversely, the smaller populations (100s to 1 000s) of Antarctic fur seals and southern elephant seals are sensitive to predation, particularly the latter as they have a high energy content (approximately 2 000 to 9 000 MJ). Populations of these seals are currently increasing or stable and I conclude that presently killer whale predation is not driving population declines, although they clearly have the potential for regulation of these smaller populations. Thus, if population sizes were reduced by bottom-up processes, if killer whale diet shifted, or if prey availability changed, top-down control by killer whales could become significant. This study provides baseline information for the informed management and conservation of killer whales at Marion Island, identifies avenues for further research, and provides a foundation for the continuation of structured and dedicated killer whale research at Marion Island. / Dissertation (MSc)--University of Pretoria, 2011. / Zoology and Entomology / unrestricted

Diplomová práce se zabývá analýzou zahraničně-kulturní a vzdělávací politiky SRN s důrazem na vzdělávací sektor ve vztahu k Rusku během třetí vlády Angely Merkelové. Pozornost je věnována především klíčovým změnám a definici normativních, institucionálních a koncepčních rovin. Úvodní část práce se věnuje základnímu uvedení do tématu, stanovení cílů, tezí a výzkumných otázek. Dále je zde popsána metodologie a kritické zhodnocení pramenů a literatury. První kapitola teoreticky vymezuje analytické koncepty soft-power, civilní mocnost, geo- ekonomická mocnost a "Wir müssen kleine Brötchen backen", které umožňují podrobněji popsat zkoumanou oblast. V této části je také definována zahraničně-kulturní politika a její hlavní instrumenty. Druhá kapitola představující empirickou část diplomové práce se podrobně věnuje vzdělávacímu sektoru zahraničně-kulturní a vzdělávací politiky SRN ve vztahu k Rusku v letech 2013 až 2017. Skrze klíčové programy a projekty jsou rozebírány cíle, tematické okruhy, programové, koncepční a částečně i finanční změny zkoumané politiky. Třetí kapitola se věnuje analýze a vyhodnocení těchto změn. Kromě toho je věnována pozornost i kontinuitě ve vybraných oblastech a efektivnosti autorem zavedeného konceptu "Wir müssen kleine Brötchen backen". Následuje závěr práce, který shrnuje...

<p>Urban areas are warmer than surrounding rural areas. During the cold of winter, warming increases surrounding host temperature and may improve the overwintering survival of marginally hardy insects like evergreen bagworms. Similarly, during the summer, it has the potential to increase the fecundity and abundance of sap feeding insect pests such as scale insects in ways that change the capacity of their natural enemies to regulate their populations. </p> <p>Although in parts of Indiana winters can be cold enough to kill bagworm eggs, they thrive in cities. I conducted field experiments to determine the extent to which impervious surface near an infestation could keep temperatures warm enough to affect bagworm survival during cold of winter. My results suggest that the percentage of live eggs inside overwintering pupae decreased as ambient temperature drops. This response was moderated by the presence of impervious surface around an infested plant. Eggs found in bagworms collected from host trees surrounded by more impervious surface had a higher chance of survival than those collected from trees with low levels of hardscape. However, impervious surface has its limit such that egg mortality was not buffered by impervious surfaces at temperatures at or below -21.67°C. Similarly, I also conducted field experiments with sap feeding insects on honeylocust trees, a commonly planted tree in cities. Hot sites had a mean daily temperature more than 1.5 °C warmer than cool sites and scale insects were more abundant and fecund on trees in the hottest part of Indianapolis compared to cooler areas. No differences were observed in rates of parasitism on the scale insect. However, I found strong density dependence relation between parasitoids and scales abundance at scale density at or below the levels present in cool sites. The top-down regulation was prevalent at or below a critical density of scale hosts. Conversely, bottom-up regulation was prevalent above this host density as pests benefit from bottom-up factors. This suggests that urban habitats helped the scales to escape biological control by resident natural enemies above critical density of scale hosts. </p> <p>My findings can be useful to landscape designers to design landscapes that are less prone to insect pests. My finding adds to a growing body of evidence that suggests that planting urban trees with lesser amount of impervious surface can help reducing the urban warming effect and increase the regulation from natural enemies. </p>

The visual sense has outstanding importance for humans’ interaction with the environment and visual attention is the key mechanism that bundles our limited cognitive resources in order to enhance the perceptual processing of the most relevant environmental features at a certain point in time. Eye-Tracking technology enables us to accurately observe peoples’ eye movement behavior i.e. overt attention. In the last decade, overt attention on real-world scenes gained increasing popularity in vision research. The higher ecological validity of such scenes in combination with a free-viewing task allows us to investigate human viewing behavior under natural conditions. In this context, the majority of previous studies focused on the impact of basal image properties, such as color and luminance differences, to quantify the extent to which our fixation behavior is guided by these so-called low-level image properties. However, in most experimental studies complex images are observed only one time, whereas we are continually confronted with repeated visual impressions in everyday life. Therefore, I introduce a repeated-presentation-design that allows scrutinizing the impact of low-level image properties and the power of scene types over time. Besides these low-level factors, I also address inter-individual differences in motivation as well as emotional components as so-called high-level factors in overt attention. Previous research on visual attention has widely neglected these factors, especially in the context of real-world images. On the basis of novel study designs and by means of various analysis techniques, I show how several low- and high-level factors influence overt attention on complex scenes, how they interact, and how eye movement parameters are interrelated. In addition to that, I provide a comprehensive review of the previous literature on emotions’ and personality traits’ impacts on visual attention. On the basis of the inconsistent understanding of core concepts in the literature, I describe how behaviorally oriented studies investigate these high-level factors in visual attention, how the interplay between emotion and attention is conceptualized from a neuroscientific perspective, and I derive several conceptual and practical recommendations for future research. Finally, I outline some new ideas and venues for future research in the general discussion of the present work, for example how eye-tracking might overcome some fundamental problems of classical testing in psychological diagnostics, or how the view of embodied cognition can help us to get a better understanding of high- and low-level factors in visual attention.

In this thesis I study several deductive systems for linear logic, its fragments, and some noncommutative extensions. All systems will be designed within the calculus of structures, which is a proof theoretical formalism for specifying logical systems, in the tradition of Hilbert's formalism, natural deduction, and the sequent calculus. Systems in the calculus of structures are based on two simple principles: deep inference and top-down symmetry. Together they have remarkable consequences for the properties of the logical systems. For example, for linear logic it is possible to design a deductive system, in which all rules are local. In particular, the contraction rule is reduced to an atomic version, and there is no global promotion rule. I will also show an extension of multiplicative exponential linear logic by a noncommutative, self-dual connective which is not representable in the sequent calculus. All systems enjoy the cut elimination property. Moreover, this can be proved independently from the sequent calculus via techniques that are based on the new top-down symmetry. Furthermore, for all systems, I will present several decomposition theorems which constitute a new type of normal form for derivations.