We analyze the policy implications of aversion to Knightian uncertainty (ambiguity) about the possibility of tipping points. We demonstrate two channels through which uncertainty aversion affects optimal policy in the general setting. The first channel relates to the policy's effect on the probability of tipping, and the second channel to its differential impact in the pre- and post-tipping regimes. We then extend a recursive dynamic model of climate policy and tipping points to include uncertainty aversion. Numerically, aversion to Knightian uncertainty in the face of an ambiguous tipping point increases the optimal tax on carbon dioxide emissions, but only by a small amount.

‘Project performance’ is the metric of delivering project objectives. This research is motivated by levels of project failure and the purpose of the research is to investigate improved project performance. The scientific spectrum is considered; arguing project management as a sub-field of management science based in ‘design science’. Despite research since the 1950s, there is no established community paradigm for project management, illustrated by multiple ‘schools of thought’ failing to stimulate performance improvement. This is investigated with respect to the changing nature of projects and their management; application in numerous industrial sectors, across increasing scope of the product lifecycle (including service projects), and the changing role of project managers as value adding ‘implementers’ rather than status ‘reporters’. Methodology examines the community paradigm and identifies the lack of community paradigm and argues that gap spotting is not appropriate. Conducting research that fills knowledge gaps does not identify underlying issues and reinforces fundamental failings. Underlying assumptions are identified and challenged. Key characteristics are examined in the context of requirements of the community paradigm. The purpose of theory is to describe, explain and predict. Some techniques describe and explain. Few, if any, predict. This locates ‘performance prediction’ as the research issue and suggests it is a missing function for performance improvement. The research focus considers single tasks within a project network. A research model of early stage deviation from plan is developed from the literature on project pathogens and incubation processes. ‘Deviation lifecycle’ as a project function is identified as having no previous evidence in literature. This is developed into a practice model extending the role of failure modes and effects analysis (FMEA) and integrating weak signals and tipping point theory to test performance. Case studies examine representative application of the model and build on the previous cases to illustrate potential for practice. The case studies were reviewed by industrial experts. The changing role of project managers to value added implementers implies a need to improve performance. Research found potential to understand and predict early stage deviation and develops the deviation lifecycle and research model. Across the case studies the research model illustrated potential application. Practical implications indicate potential contribution of project management techniques based on prediction rather than traditional reporting. Developing the community paradigm based on design science is discussed as further work. The originality of the research challenges the lack of theoretical foundation for project management by discussion of the community paradigm and proposes design science as a candidate. The work identifies ‘prediction’ as a relevant but missing function from the project management ‘toolbox’, and introduces the concept of the deviation lifecycle and note no previous literature. The research develops an industrial research model that extends the application of FMEA to examine ‘performance’ and integrates weak signals and tipping point analysis to manage the resolution.

Climate change is increasing the frequency and extent of high-severity disturbance, with potential to alter vegetation community composition and structure in environments sensitive to tipping points between alternative states. Shrub species display a range of characteristics that promote resistance and resilience to disturbance, and which yield differential post-disturbance outcomes. We investigated differences in shrub patch size and stem density in response to variations in fire severity, vegetation community, and post-disturbance reproductive strategies in Sky Island forested ecosystems in the southwestern United States. Patterns in shrub structure reflect the effects of fire severity as well as differences among species with alternate post-fire reproductive strategies. Increased fire severity correlates with larger patch sizes and greater stem densities; these patterns are observed across multiple fire events, indicating that disturbance legacies can persist for decades. High severity fire produces the largest shrub patches, and variance in shrub patch size increases with severity. High severity fire is likely to promote expansion of shrub species on the landscape, with implications for future community structure. Resprouting species have the greatest variability in patch structure, while seeding species show a strong response to disturbance: resprouting species dominateatlowdisturbanceseverities,andobligateseedersdominatehighseverityareas. Differential post-fire reproductive strategies are likely to generate distinct patterns of vegetation distribution following disturbance, with implications for community composition at various scales. Shrub species demonstrate flexible responses to wildfire disturbance severity that are reflected in shrub patch dynamics at small and intermediate scales.

Made available in DSpace on 2016-08-10T10:34:55Z (GMT). No. of bitstreams: 1 Ana Cristina de Deus e Sousa.pdf: 5798246 bytes, checksum: d25bae7becb7f793163c7c7b25b36887 (MD5) Previous issue date: 2009-10-27 / This study aims to review the document that registers the tipping of the town of Goias as World Heritage O Dossiê de Goiás, and its blatant linkage to the poet Cora Coralina, an odd character who perfectly characterizes how it is to be born and raised in Goias. Cora's poetry, while expressing the memory and identity of Vila Boa inhabitants, served as an argumentative basis in the preparation of this dossier in what concerns the town original aspects as an authentic representative of the Brazilian colonial period, and in which simplicity and ancient customs remain. The house of the poet has become a symbol of Goias. The poem which praises it more, Goiás, minha cidade, was used on the front page of the dossier in a clear demonstration of this remarkable woman s strength, as well as her power in the local culture. This written account determines the persistence of Goias over the centuries and justifies its importance for all people through the defense of its conservation and the resultant need to preserve the architectural site. / Este trabalho tem por finalidade a análise do documento de tombamento da cidade de Goiás como Patrimônio da Humanidade o Dossiê de Goiás, e sua flagrante vinculação à poetisa Cora Coralina, personagem ímpar na caracterização do jeito de ser goiano. A poesia de Cora, ao expressar a memória e a identidade vilaboenses, serviu de base argumentativa na elaboração do Dossiê quanto à originalidade da cidade como autêntica representante do período colonial brasileiro que ainda conserva a simplicidade e os hábitos de outros tempos. A casa da poetisa tornou-se um dos símbolos de Goiás. O poema que mais a exalta: Goiás, minha cidade, foi utilizado na primeira pagina do Dossiê em uma clara demonstração da força dessa mulher marcante e forte na projeção da cultura local. O Dossiê estabelece a perenidade de Goiás ao longo dos séculos e justifica sua importância para todos os povos por meio da defesa da conservação e da conseqüente necessidade de preservação do sítio arquitetônico.

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2018-09-25T17:50:35Z No. of bitstreams: 1 2016 - Miqu?ias Permanhani.pdf: 8462509 bytes, checksum: 23e7a0fff474c07ddaca0105da127c59 (MD5) / Made available in DSpace on 2018-09-25T17:50:35Z (GMT). No. of bitstreams: 1 2016 - Miqu?ias Permanhani.pdf: 8462509 bytes, checksum: 23e7a0fff474c07ddaca0105da127c59 (MD5) Previous issue date: 2016-09-29 / CAPES / ?BRS Vit?ria? is the first seedless grape cultivar launched by Embrapa Grape and Wine with tolerance to downy mildew (Plasmopora viticola), in addition to presenting high fertility of buds and a special flavor similar to raspberry but its clusters are compact, which requires the establishment of specific management techniques to reduce compactness. Two trials were conducted in the northwestern S?o Paulo state aiming to evaluate the agronomic performance of ?BRS Vit?ria? grapevine grafted onto different rootstocks, as well as the effect of shoots and/or clusters tipping together with the application of gibberellic acid (GA3) on production and characteristics of fruits. In the first experiment, the treatments were constituted by the combination of ?BRS Vitoria? grapevine grafted onto rootstocks ?Paulsen 1103?, ?Kober 5BB?, ?IAC 766? and ?IAC 572?, while in the second trial four tipping modalities (control or without tipping, shoots, clusters, shoots + clusters) were done in the end of flowering stage, associated or not with the GA3 application (0 and 30 mg L-1) when berries had 6-8 mm of diameter. It was verified that the period from beginning of ripening to harvest of clusters had greater influence in the production cycle (from pruning to harvest) of scion/rootstock combinations, presenting longer and shorter interval, respectively, when grafted onto ?IAC 766? and ?Paulsen 1103?. There was obtained higher production and vegetative vigor when grafted onto ?IAC 766? and ?IAC 572?, being that the ?IAC 766? provided the higher average of clusters weight and berries size. The rootstocks did not influence in total soluble solids (TSS) content and titratable acidity (TA) of the berries. In addition, there was no effect of the tipping treatments on production and characteristics of fruits, except for the TSS content, indicating that this technique may not be efficient to reduce clusters compactness of ?BRS Vitoria? grape or that it should not be performed during the flowering period. However, the clusters tipping in association with the use of GA3 allowed a higher average TSS content by reducing the difference between berries at the top and tip of cluster. One single application of GA3 at 30 mg L-1 when berries had 6-8 mm of diameter provided an increase in fruits weight and size but there was no significant effect (p> 0.05) on production and, although it has not caused a negative impact on quality of ?BRS Vitoria? grape, a decrease was observed in TSS content and TSS/TA ratio of the berries. / ?BRS Vit?ria? ? a primeira cultivar de uva sem sementes lan?ada pela Embrapa Uva e Vinho com toler?ncia ao m?ldio (Plasmopora viticola), al?m de apresentar alta fertilidade de gemas e um sabor especial semelhante ? framboesa, por?m seus cachos s?o compactos, o que exige o estabelecimento de t?cnicas espec?ficas de manejo para reduzir a compacidade. Foram conduzidos dois experimentos na regi?o noroeste do estado de S?o Paulo com o objetivo de avaliar o desempenho agron?mico da videira ?BRS Vit?ria? enxertada sobre diferentes porta-enxertos, bem como, o efeito do desponte de ramos e/ou de cachos em conjunto com a aplica??o do ?cido giber?lico (GA3) na produ??o e nas caracter?sticas dos frutos. No primeiro experimento, os tratamentos foram constitu?dos pela combina??o da videira ?BRS Vit?ria? enxertada sobre os porta-enxertos ?Paulsen 1103?, ?Kober 5BB?, ?IAC 766? e ?IAC 572?, enquanto no segundo experimento, foram realizadas quatro modalidades de desponte (testemunha ou sem desponte, ramos, cachos, ramos + cachos) no est?gio de fim do florescimento, associados ou n?o com a aplica??o de GA3 (0 e 30 mg L-1) quando as bagas apresentavam 6-8 mm de di?metro. Foi verificado que o per?odo do in?cio da matura??o ? colheita dos cachos teve maior influencia no ciclo de produ??o (da poda ? colheita) das combina??es copa/porta-enxerto, apresentando intervalo mais longo e mais curto, respectivamente, quando sobre ?IAC 766? e ?Paulsen 1103?. Obteve-se maior produ??o e vigor vegetativo sobre ?IAC 766? e ?IAC 572?, sendo que o ?IAC 766? proporcionou maiores m?dias de massa de cachos e tamanho de bagas. Os porta-enxertos n?o influenciaram no teor de s?lidos sol?veis totais (SST) e acidez titul?vel (AT) das bagas. Al?m disso, n?o houve efeito do desponte na produ??o e nas caracter?sticas dos frutos, exceto para o teor de SST, indicando que essa t?cnica pode n?o ser eficiente para reduzir a compacidade dos cachos de uva ?BRS Vit?ria? ou que n?o deve ser realizada durante o per?odo de florescimento. No entanto, o desponte de cachos associado com o uso do GA3 possibilitou um maior teor m?dio de SST ao reduzir a diferen?a existente entre bagas na parte superior e na ponta do cacho. Uma ?nica aplica??o de GA3 a 30 mg L-1 quando as bagas tinham 6-8 mm de di?metro proporcionou um aumento na massa e no tamanho dos frutos, por?m n?o houve efeito significativo (p >0.05) na produ??o e, embora n?o tenha causado um impacto negativo na qualidade da uva ?BRS Vit?ria?, observou-se uma redu??o no teor de SST e na rela??o SST/AT das bagas.

Analyses of data with missing values often require assumptions about missingness mechanisms that cannot be assessed empirically, highlighting the need for sensitivity analyses. However, universal recommendations for reporting missing data and conducting sensitivity analyses in empirical studies are scarce. Both steps are often neglected by practitioners due to the lack of clear guidelines for summarizing missing data and systematic explorations of alternative assumptions, as well as the typical attendant complexity of missing not at random (MNAR) models. We propose graphical displays that help visualize and systematize the results of sensitivity analyses, building upon the idea of "tipping-point" analysis for experiments with dichotomous treatment. The resulting "enhanced tipping-point displays" (ETP) are convenient summaries of conclusions drawn from using different modeling assumptions about the missingness mechanisms, applicable to a broad range of outcome distributions. We also describe a systematic way of exploring MNAR models using ETP displays, based on a pattern-mixture factorization of the outcome distribution, and present a set of sensitivity parameters that arises naturally from such a factorization. The primary goal of the displays is to make formal sensitivity analyses more comprehensible to practitioners, thereby helping them assess the robustness of experiments' conclusions. We also present an example of a recent use of ETP displays in a medical device clinical trial, which helped lead to FDA approval. The last part of the dissertation demonstrates another method of sensitivity analysis in the same clinical trial. The trial is complicated by missingness in outcomes "due to death", and we address this issue by employing Rubin Causal Model and principal stratification. We propose an improved method to estimate the joint posterior distribution of estimands of interest using a Hamiltonian Monte Carlo algorithm and demonstrate its superiority for this problem to the standard Metropolis-Hastings algorithm. The proposed methods of sensitivity analyses provide new collections of useful tools for the analysis of data sets plagued with missing values. / Statistics

Mobile boom cranes are used throughout the world to perform important and dangerous manipulation tasks. Given their mobility, these types of cranes can quickly be moved into position. Generally, their base is then fixed and stabilized before they start lifting heavy materials. The usefulness of these cranes can be greatly improved if they can utilize their mobile base during the lifting and transferring phases of operation. This ability greatly expands the workspace by combining base motion with the rotation, lifting, and luffing motions. Of course, the cranes lose some stability margin when a payload is attached. The stability is further degraded when the payload swings. This Master's Thesis presents a stability study of such cranes. As a first step, a static stability analysis of a boom crane is conducted in order to provide basic insights into the effects of the payload weight and crane configuration. Then, a semi-dynamic method is used to take the payload swing into account. As a final step, the results of a dynamic stability analysis obtained by using a multi-body simulation of the boom crane are compared to the outcomes of the previous approaches. This provides conclusions for the practical application of stability analysis. A control method that limits payload swing, and thereby improves stability, is also presented.

No description available.

Global biodiversity losses are being driven by human actions, and coral reef communities are not immune. Local anthropogenic stress and global climate change are rapidly changing coral reefs, through coral bleaching and mortality. How these stressors impact the biodiversity and community structure of corals on tropical reefs will not only affect the communities of fish and invertebrates that rely on coral reefs, but they could have lasting impacts on ecosystem functioning. The record-breaking marine heatwave caused by the 2015/2016 El Niño was superimposed on a strong local human disturbance gradient on Kiritimati, Kiribati, allowing for the investigation of how these combined disturbances affect coral communities. In Chapter 2, I investigated how soft coral cover varies with these disturbances and natural environmental factors, using benthic photoquadrats collected on Kiritimati’s forereefs from 2007 to 2019. Additionally, I conducted a literature review to establish what is already known about soft coral and disturbances, to compare Kiritimati data to that found in the literature. I show that soft corals are grossly understudied, with only a fifth (19/94) of coral studies presenting any results of heat stress effects on soft corals, and even fewer (5%) presenting taxonomic-specific results. On Kiritimati, prior to the 2015/2016 El Niño, soft corals were more common at sheltered sites with lower net primary productivity, but no effect of local disturbance was found. Soft corals were, however, highly vulnerable to heat stress, with a documented complete loss after the heatwave. I also show that soft coral skeletons persisted for years after the heatwave and provided substrate for hard coral recruitment. In Chapter 3, I examined how local and global stressors affected coral diversity, using community composition photoquadrat data collected from 2013 to 2017, and developed a conceptual framework for understanding effects of multiple stressors, when there are both discrete and continuous stressors. Coral alpha diversity (assessed as Hill diversity) exhibited a non-linear relationship with local anthropogenic stress, peaking at intermediate levels, and was negatively impacted by the marine heatwave, such that sites tended to decrease in both coral richness and evenness. Coral beta diversity (assessed as community composition turnover) was significantly impacted by both stressors, but sites exposed to higher levels of anthropogenic stress tended to experience less turnover during the heatwave. Explicitly considering the relationships between the two stressors, I found that it varied depending on the intensity of anthropogenic stress and the diversity metric (i.e., richness vs. composition) examined. For Hill-Richness, I found a tipping point at moderate levels of local anthropogenic stress, below which there was an additive response and above which the response tended towards synergy. In contrast, for Hill-Shannon and Hill-Simpson the responses were additive and there was an antagonistic effect between stressors for community composition. By using the frameworks outlined in this thesis for reporting changes to soft coral due to disturbances, and examining relationships between discrete and continuous stressors, we may better predict how reefs will look in the future and what actions will conserve and assist in the recovery of coral reef ecosystems. / Graduate / 2022-08-10

Memoria para optar al título de Geógrafo / En la comuna de El Quisco en la Región de Valparaíso, como en la mayoría de las comunas del país, no son ajenas las complicaciones que conlleva la gestión de los residuos, dichas complicaciones radican en el problema del florecimiento de microbasurales en diversos sectores del territorio comunal, que poseen ciertas características geográficas, sociales o sectoriales que pueden explicar su localización mediante el uso de los SIG. Sin embargo, la situación de los microbasurales no solo tienen explicaciones de su generación, sino que también suelen generar conflictos en la comunidad, el sector público y sectorialmente, como sucede con el turismo, principalmente en épocas estivales. Estos conflictos suelen expresarse de diversas formas y en distintas plataformas, pero tienden a invisibilizarse producto de la normalidad y de la cotidianeidad que estos han adquirido a través de los años y de la poca cultura ambiental que posee gran parte de la población nacional. De acuerdo a la ubicación, al tamaño, y a la población que habita los lugares donde se producen, algunos casos pueden generar tal cantidad de problemas graves, que se puede hablar de los microbasurales como generadores de un conflicto socioambiental. / In the commune of El Quisco in the Región de Valparaíso, as in most of the country's municipalities, are no stranger, the complications that involves the management of waste, this complications lies in the problem of the flowering of illegal dumping of waste in various sectors of the communal territory. Geography, social or sectoral networks can explain their location through the use of GIS. However, the situation of the illegal dumping of waste not only have explanations of their generation, but also often generate conflicts in the community, the public sector and sectorally, as it happens with tourism, mainly in the summer. These conflicts are usually a way of expressing the different forms and different platforms, but also a product of normality and everyday life that has been acquired over the years and the little environmental culture that has a large part of the national population. According to the location, the size, and the population that inhabits the places where they are produced, some cases can generate such amount of serious problems, that can talk about the fly-dumping as a socio-environmental conflict.