Introduction and Establishment of Cyrtobagous salviniae Calder and Sands (Coleoptera: Curculionidae) for the Control of Salvinia minima Baker (Salviniaceae), and Interspecies Interactions Possibly Limiting Successful Control in Louisiana

Common salvinia, Salvinia minima Baker, is a floating aquatic invasive macrophyte that obstructs waterways and causes problems in wetlands across Louisiana and Texas. The salvinia weevil, Cyrtobagous salviniae Calder and Sands, has been released in over 14 countries around the world for the biological control of Salvinia spp. We successfully monitored the introduction and establishment of C. salviniae on S. minima in southern Louisiana between 2006 and 2010. Cyrtobagous salviniae significantly lowered the biomass of S. minima and increased the number of terminal buds damaged but had no significant impact on pH, dissolved oxygen, conductivity, surface temperature, percent of surface coverage, or percent of the mat that was green. Restricting access to the S. minima mat from the red imported fire ant, Solenopsis invicta Buren, significantly increased the number of C. salviniae, suggesting that S. invicta should be controlled where possible to maximize the success of the biological control program. While collecting arthropods associated with S. minima, we identified 5,773 individuals that represent 176 species within 62 families and seven orders including four currently undescribed species, and seven species of semi]aquatic Curculionidae (five of which have been used in biological control programs). We collected higher numbers of taxa than previous studies, but most of the species are previously known as hydro] or hygrophilous, indicating the differences may have been due to collection methods. Collecting locations were clustered into five groups based on secondary aquatic vegetation and evaluated by cluster for community composition and similarity. We found no support for the spatial heterogeneity hypothesis, as our most diverse community is one of the least spatially complex, suggesting other factors are affecting community composition. Findings included successful establishment of C. salviniae, recommendation to control S. invicta around C. salviniae release sites, improved methods for collecting insects associated with floating aquatic vegetation, and contributions to the knowledge of the biodiversity of Louisianafs backwater swamps. In addition to providing new information on interactions between C. salviniae and S. minima, these studies will be useful in designing,evaluating, and monitoring releases of other biological control agents on floating aquatic macrophytes

Out in the Open: A Geoarchaeological Approach to Open-Air Surface Archaeology in the Semi-Arid Interior of South Africa’s Western Cape

Southern African research into the behavioural evolution of Late Pleistocene human adaptability, flexibility, and innovation is typically pursued through the lens of rock shelter deposits. However, rock shelters only cover a very small, geographically specific area of the subcontinent, distorting our understanding of change in human-environment interaction and demography. While still under-represented and under-explored in regional syntheses, more studies are looking to open-air archaeology to fill this geographic void in Late Pleistocene research. These studies either pursue a landscape approach that prioritises spatial coverage, or site-bound excavation to maximise temporal control. However, few investigate the depositional and erosional phenomena involved in the formation of surface archaeology and its surrounding landscape. To rectify this disparity, this thesis explores the complex spatio-temporal relationship between surface archaeology and the formation history of Uitspankraal (UPK) 7 by combining multiple interdisciplinary methods from the Earth and archaeological sciences: randomised surface survey and sampling, geomorphometry, geophysical survey, granulometry, XRD analysis, OSL dating, artefact mapping, and assemblage composition and artefact condition analysis. UPK7 is located in the semi-arid Doring River valley and yields surface archaeology that implies occupation from the Still Bay to the Historic period. Results show that it is an eroding series of source-bordering dunes draped across a palaeoterrace and a hillslope of bedrock and colluvium. UPK7 formed through rapid but pulsed sediment accumulation over at least the last 80 ka, with periods of surface deflation and exposure that facilitated artefact redistribution. Despite the abundance of Late Pleistocene archaeology at UPK7, erosion currently outpaces deposition and deposit stabilisation. Erosion has accelerated in at least the last 5,000 years and especially within the last 300 years, suggesting feedback between Holocene aridification, an increase in oscillations between wet-dry conditions, and an increase in human-ungulate activity in the study area. Together these conditions have differentially erased younger deposits, exposing the consolidated Late Pleistocene sediment and the more ancient material it preserves. The visibility, spatio-temporal distribution, and preservation of UPK7’s surface artefacts reflect the locality’s topography, the timing of their discard and the duration and process of sediment accumulation and erosion. The spatial patterning and diversity of time-diagnostic and non-diagnostic artefacts is shown to correspond with the depositional age of their underlying substrate in areas where topographic conditions minimize or reduce the impact of surface runoff, but where sediment deflation persists. When artefacts are assessed at the scale of the archaeological epoch the spatial distribution of Middle Stone Age artefacts shows a significant association with the oldest deposit, Lower Red. The spatial distribution of Later Stone Age artefacts is significantly associated with Upper Yellow sediment, as opposed to the older Lower Red substrate and the younger Indurated Sand. The findings presented in this thesis caution against forming behavioural interpretations from spatial patterns in surface material without examining their post-depositional history and without forming an understanding of the coevolution of archaeological and landscape formation. This study underscores the need for incorporating a geoarchaeological approach into Late Pleistocene open-air research to improve southern Africa’s landscape-scale insight into greater Africa’s human behavioural evolution

Analyzing Granger causality in climate data with time series classification methods

Attribution studies in climate science aim for scientifically ascertaining the influence of climatic variations on natural or anthropogenic factors. Many of those studies adopt the concept of Granger causality to infer statistical cause-effect relationships, while utilizing traditional autoregressive models. In this article, we investigate the potential of state-of-the-art time series classification techniques to enhance causal inference in climate science. We conduct a comparative experimental study of different types of algorithms on a large test suite that comprises a unique collection of datasets from the area of climate-vegetation dynamics. The results indicate that specialized time series classification methods are able to improve existing inference procedures. Substantial differences are observed among the methods that were tested

Assessment of sustainable tourism development in Windhoek, Namibia : Development and implementation of an adapted criteria catalogue in line with respective local conditions.

The aim of this master thesis is to assess, analyse and evaluate the sustainability of a tourism destination while taking the local conditions into consideration by adapting the assessment instrument. The case study of the city Windhoek in Namibia is used to identify particular local features and make them measurable using an adapted criteria catalogue. In addition to a comprehensive secondary analysis, the database consists of different qualitative and quantitative methods, which are conducted during a field research phase in the form of expert interviews, visitor and local surveys and observations at relevant POIs. The content and statistical evaluation of the data is the basis for the assessment of the indicators, the sustainability dimensions and the global evaluation of sustainability in the destination. The weaknesses identified in the course of the research are then recorded in the form of recommended actions. As this thesis is part of the development policy cooperation between the City of Bremen and the City of Windhoek, the communication platform, to make the research results available to the City of Windhoek, has been established. Besides the adaptation of the catalogue, a refinement of the method for future measurement and evaluation of sustainability in destinations with different framework conditions is developed. Based on a critical reflection and the issue of the applicability of the model to other destinations, technical and content-related recommendations for the catalogue adaptation to local circumstances are made

Context-Aware Recommendation Systems in Mobile Environments

Nowadays, the huge amount of information available may easily overwhelm users when they need to take a decision that involves choosing among several options. As a solution to this problem, Recommendation Systems (RS) have emerged to offer relevant items to users. The main goal of these systems is to recommend certain items based on user preferences. Unfortunately, traditional recommendation systems do not consider the user’s context as an important dimension to ensure high-quality recommendations. Motivated by the need to incorporate contextual information during the recommendation process, Context-Aware Recommendation Systems (CARS) have emerged. However, these recent recommendation systems are not designed with mobile users in mind, where the context and the movements of the users and items may be important factors to consider when deciding which items should be recommended. Therefore, context-aware recommendation models should be able to effectively and efficiently exploit the dynamic context of the mobile user in order to offer her/him suitable recommendations and keep them up-to-date.The research area of this thesis belongs to the fields of context-aware recommendation systems and mobile computing. We focus on the following scientific problem: how could we facilitate the development of context-aware recommendation systems in mobile environments to provide users with relevant recommendations? This work is motivated by the lack of generic and flexible context-aware recommendation frameworks that consider aspects related to mobile users and mobile computing. In order to solve the identified problem, we pursue the following general goal: the design and implementation of a context-aware recommendation framework for mobile computing environments that facilitates the development of context-aware recommendation applications for mobile users. In the thesis, we contribute to bridge the gap not only between recommendation systems and context-aware computing, but also between CARS and mobile computing.<br /

Water Quality Criteria and the Biota of Chesapeake Bay

Section 1: Ecological Concepts and Environmental Factors Affecting Chesapeake Bay. Section 2: Summaries of the Biology of the most Significant Bay Organisms. Section 3: Chesapeake Bay Communities: General Ecological Descriptions and Selection of Several Communities for more Detailed Study. Section 4: Water Quality Standards and Criteria Pertinent to the Chesapeake Bay. Section 5: Applicability of the Chesapeake Bay Hydralic Model for Biological Problems

Essays on Welfare, Demand and Resilience to Food Insecurity in Rural Ethiopia

I prezzi dei generi alimentari sono cresciuti in modo considerevole in Etiopia a partire dal 2004. Questa tesi esamina a fondo gli effetti distributivi degli alti prezzi dei generi alimentari nelle zone rurali dell’Etiopia. Utilizzando il Rapporto di Beneficio Netto non parametrico ed il Sistema Quadratico di Domanda Quasi Ideale nonché stimando la Variazione Compensata, dimostra come gli alti prezzi dei generi alimentari possano avere effetti positivi sul benessere sociale delle famiglie rurali a livello aggregato. Tuttavia, i guadagni non sono distribuiti uniformemente tra le famiglie; una significativa percentuale di esse sono compratrici nette di cereali e potrebbero essere sfavorite da un aumento dei prezzi dei cereali qualora non beneficiassero di un aumento del reddito associato ad attività diverse dall’agricoltura. Teoreticamente, le famiglie rurali dovrebbero beneficiare di un aumento del prezzo dei generi alimentari poiché sono sia produttori sia consumatori dei prodotti. Un aumento della produttività agricola, attraverso l’intensificazione e la diversificazione delle produzioni, è un’importante strumento di politica economica che può limitare gli effetti negativi, di breve e di lungo periodo, sugli acquirenti netti rurali di generi alimentari derivanti da un aumento del loro prezzo. La tesi esamina anche la resilienza alla mancanza di cibo, la stagionalità nel consumo del cibo e la partecipazione nel mercato così come il ruolo dei trasferimenti monetari e delle preferenze dei beneficiari degli stessi.Food prices in Ethiopia considerably rose since 2004. This thesis thoroughly examines the distributional impacts of high food prices in rural Ethiopia. Using the non-parametric Net Benefit Ratio analysis as well as Quadratic Almost Ideal Demand System and estimating Compensated Variation, it shows high food prices have positive impact on the welfare of rural households at aggregate levels. The gains, however, are not evenly distributed among households; large proportion of them are net cereal buyers (major staples) and could be adversely affected by rising cereal prices unless compensated by increase in income from off-farm activities. Theoretically, rural households should benefit from rising food prices as they are both consumers and producers of the products. Promoting agricultural productivity, through intensification and diversification, is an important policy tool to overcome short and long-run negative impacts of high food prices on rural net buyers. It also examines resilience to food insecurity, food consumption seasonality and market participation as well as cash transfers and beneficiaries preferences

HUMAN EXPOSURE TO FOOD CONTAMINANTS THROUGHOUT DIET: ASSESSMENT THROUGH TDS, BIOACCESSIBILITY AND CYTOTOXICITY ASSAYS IN VITRO

Human health and environmental sustainability are interlinked through diet since food inges- tion is one of the main routes of exposure to several contaminants in humans. In this sense, the transformation of healthy diets from sustainable food systems is crucial to achieving the Sustainable Development Goals defined by the United Nations, namely goals 2 and 3, related to food security and ensuring healthy lives, respectively. The present thesis aimed at i) char- acterising the presence of chemical contaminants in essential food items of the Portuguese diet; ii) evaluating the geographical influence and the importance of diffuse sources on trace ele- ments levels in food; iii) assessing the potential risk of halogens, metals and metalloids to hu- mans through food, and iv) estimating the bioaccessibility of food contaminants and their po- tential toxicity in intestinal cells. The results revealed that regarding the consumption of rele- vant food groups in the Portuguese population, the seafood group presented the highest As, Br, Cd and Pb levels compared to other analysed food groups, with an increased relative risk for total As and a clear progression of Cd relative risk with increasing consumption frequency of seafood. The results also demonstrated that the trace elements in areas affected by wildfires identified a hazard, especially for As, and other trace elements such as Cd, Br, Cr and Sr. More- over, the bioaccessible fractions of As obtained after in vitro digestion of seafood were higher than the EC50 obtained for human intestine cells. This thesis contributed to increasing the knowledge about chemical contamination in food and their risk to the human population, as well as to the importance of using different approaches, including TDS methodology, risk as- sessment strategies, and in vitro assays, as essential tools for developing new monitoring meth- odologies in sustainable food systems and SDGs achievement.A saúde humana e a sustentabilidade ambiental estão interligadas através da dieta, sendo a ingestão uma das principais vias de exposição a contaminantes nos seres humanos. Neste sen- tido, a transformação de dietas saudáveis a partir de sistemas alimentares sustentáveis é cru- cial para alcançar os Objetivos de Desenvolvimento Sustentável definidos pelas Nações Uni- das, nomeadamente os objetivos 2 e 3, relacionados com a segurança alimentar e a garantia de vidas saudáveis, respetivamente. A presente tese visa i) caracterizar a presença de contami- nantes químicos em alimentos essenciais da dieta portuguesa; ii) avaliar a influência geográ- fica e a importância de fontes difusas nos níveis de elementos vestigiais nos alimentos; iii) avaliar o potencial risco de halogéneos, metais e metalóides nos seres humanos através de alimentos, iv) estimar a bioacessibilidade de contaminantes alimentares e a sua potencial toxi- cidade em células intestinais. Os resultados revelaram que em relação ao consumo de grupos alimentares relevantes na população portuguesa, o grupo de produtos do mar apresentou os níveis mais elevados de As, Br, Cd e Pb comparativamente aos outros grupos analisados, um aumento do risco relativo de As total e uma progressão do risco relativo de Cd aumentando com a frequência de consumo de produtos do mar. Os resultados também demonstraram que os elementos vestigiais nas áreas afetadas pelos incêndios identificaram um risco, especial- mente para As, Cd, Br, Cr e Sr. Evidenciaram que as frações bioaccessíveis de As após digestão in vitro dos produtos do mar foram superiores ao EC50 obtido nas células intestinais humanas. Esta tese contribuiu para aumentar o conhecimento sobre a contaminação química nos alimen- tos e o seu risco para a população humana, bem como para a importância de utilizar diferentes abordagens, incluindo a metodologia TDS, estratégias de avaliação de risco, e ensaios in vitro, para o desenvolvimento de novas metodologias de monitorização em sistemas alimentares sustentáveis e o alcance de ODS