79 research outputs found

    Analysis of human mobility patterns from GPS trajectories and contextual information

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    This work was supported by the EU FP7 Marie Curie ITN GEOCROWD grant (FP7- PEOPLE-2010-ITN-264994).Human mobility is important for understanding the evolution of size and structure of urban areas, the spatial distribution of facilities, and the provision of transportation services. Until recently, exploring human mobility in detail was challenging because data collection methods consisted of cumbersome manual travel surveys, space-time diaries or interviews. The development of location-aware sensors has significantly altered the possibilities for acquiring detailed data on human movements. While this has spurred many methodological developments in identifying human movement patterns, many of these methods operate solely from the analytical perspective and ignore the environmental context within which the movement takes place. In this paper we attempt to widen this view and present an integrated approach to the analysis of human mobility using a combination of volunteered GPS trajectories and contextual spatial information. We propose a new framework for the identification of dynamic (travel modes) and static (significant places) behaviour using trajectory segmentation, data mining and spatio-temporal analysis. We are interested in examining if and how travel modes depend on the residential location, age or gender of the tracked individuals. Further, we explore theorised “third places”, which are spaces beyond main locations (home/work) where individuals spend time to socialise. Can these places be identified from GPS traces? We evaluate our framework using a collection of trajectories from 205 volunteers linked to contextual spatial information on the types of places visited and the transport routes they use. The result of this study is a contextually enriched data set that supports new possibilities for modelling human movement behaviour.PostprintPeer reviewe

    Abstracts of the 10th Conference of the Italian Society of Agricultural Engineering

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    GIS-enabled Spatial Analysis and Modeling of Geotechnical Soil Properties for Seismic Risk Assessment of Levee Systems.

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    Flood protection systems are complex, interconnected engineered systems, where failure at one location means the failure of the entire system. Earthen levees, the systems’ major component, are at risk from many causes of failure including seepage, erosion and instability due to seismic loading, yet there are currently no guidelines available for the seismic design of levees. Levees stretch for long distances and are formed through various geologic processes and human activities over time, however information regarding soil properties is collected only at limited point locations and varies significantly both laterally and with depth. Levee vulnerability analyses are currently performed only at locations with known soil properties. Prediction of levee performance in locations where no soil data is available becomes a limitation for system risk assessment studies. A simplified methodology is proposed to predict soil variability in riverine geologic environments for the seismic risk assessment of earthen levee systems. A key step in this methodology is to provide a continuous characterization of soil conditions throughout the system. The proposed model correlates soil properties to preselected regional variables and is implemented, using geostatistical kriging, in a Geographic Information Systems (GIS) environment. GIS was crucial in this research and proved to be the appropriate platform for input, manipulation, analysis, and output presentation of spatial and non-spatial data. Correlation relationships between soil strength parameters and geological and river geometry factors are presented for a pilot study area in California. Global observations that apply across the study area included the increasing trend of shear strength, Su, with increasing distance from the river, and decreasing trend of Su with increasing river Sinuosity Index levels. Only local trends were observed in the relation of friction angle, ϕ, with Sinuosity Index, as well as in the relation of Su and ϕ with geological formations. The proposed methodology also includes steps for seismic response analysis of levee segments, and flood scenarios in protected areas. Since seismic response of earthen structures is controlled primarily by input ground motions, a methodology for selecting ground motions based on their mean period, Tm, for liquefaction triggering assessment of levees is also developed.Ph.D.Civil EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/91571/1/msaadi_1.pd

    Evaluation of ecosystem services and conflicts associated with native and exotic wild ungulates

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    El funcionamiento de los ecosistemas incluye todos aquellos ciclos de materia y energía, así como la interacción entre los organismos. El funcionamiento natural ha sido alterado por las actividades humanas, especialmente la biodiversidad, provocando la modificación de las interacciones entre las distintas especies. Actualmente, la comunidad científica ha reconocido una crisis de biodiversidad por causas antropogénicas asociada a la extinción de especies o la introducción de especies exóticas. Esta pérdida de biodiversidad puede desembocar en efectos negativos sobre el bienestar humano, ya que dicho bienestar está asociado con los ecosistemas y sus componentes (las sociedades obtienen beneficios de los ecosistemas). Todos aquellos beneficios que los humanos obtienen de los ecosistemas son servicios ecosistémicos, como por ejemplo alimentos, herramientas, el mantenimiento de hábitats o incluso aspectos culturales relacionados. Uno de los grupos taxonómicos más relacionado con los humanos es el de los ungulados. Sin embargo, las relaciones entre los humanos y los ungulados silvestres dependen del contexto. En los países en vías de desarrollo las poblaciones de ungulados silvestres están en descenso, mientras que en los países desarrollados sus poblaciones están creciendo tanto en abundancia como en distribución. Este proceso, denominado “rewilding” en inglés y que podríamos traducir como reconstrucción de los ecosistemas, ha favorecido la aparición de interacciones negativas entre los humanos y los ungulados silvestres, como por ejemplo los daños a la agricultura y a la silvicultura. Para evitar o mitigar estos conflictos se emplean distintas herramientas de gestión como el vallado o los aportes suplementarios. Por lo tanto, la investigación sobre los ungulados y su relación con las personas debe abordarse desde una perspectiva socio-ecológica. Esta tesis se centra en las relaciones entre las personas y los ungulados silvestres, tanto en las interacciones positivas como negativas, y las herramientas de gestión empleadas para la mitigación de los conflictos. Concretamente esta tesis pretende evaluar: i) el estado del arte de la investigación sobre las interacciones humanoungulados (Capítulo 1); ii) los beneficios y perjuicios que proveen los ungulados silvestres para dos agentes implicados: la comunidad científica y los pastores (Capítulo 2); iii) el solapamiento de nicho entre la cabra montesa (Capra pyrenaica), especie nativa, y el arrui (Ammotragus lervia), especie exótica en la península ibérica, como ejemplo de un conflicto de conservación (Capítulo 3); iv) los efectos de los aportes suplementarios como herramienta de gestión sobre la especie objeto de la gestión (el arrui), otras especies no objetivo y las alteraciones en las propiedades edáficas (Capítulos 4 y 5). En el Capítulo 6 discutimos los resultados obtenidos en los capítulos anteriores. Para establecer el estado del arte con respecto a las interacciones que se dan entre los humanos y los ungulados silvestres, revisamos las publicaciones científicas sobre este tema. Este capítulo mostró que los artículos científicos abordan los estudios, principalmente, desde la perspectiva de los conflictos, teniendo en poca consideración los servicios ecosistémicos. En general, la mayoría de las publicaciones tienen en consideración a agentes implicados, siendo los principales actores sociales relacionados con los ungulados silvestres los gestores ambientales y los cazadores. Además, las herramientas de gestión empleadas para la mitigación de los conflictos no suelen ser evaluadas, aun siendo recomendadas algunas de ellas como el control letal y el uso de barreras y elementos disuasorios. En el Capítulo 2 abordamos las interacciones entre humanos y ungulados silvestres desde la perspectiva del nuevo término “Contribuciones de la Naturaleza para las Personas” (NCP por sus siglas en inglés) de dos de los agentes implicados menos considerados en las publicaciones científicas, es decir, los propios investigadores y los pastores. En este trabajo examinamos y comparamos las prioridades científicas a partir de los estudios publicados y las percepciones de los pastores respecto a los NCP proporcionados por los ungulados silvestres. Revisamos artículos científicos sobre los NCP proporcionados por los ungulados en España y realizamos entrevistas en profundidad a pastores en sistemas ganaderos extensivos donde los ungulados domésticos coexisten con los silvestres. Después comparamos si las prioridades científicas coinciden con lo percibido por los pastores. Ambos agentes implicados destacaron más los NCP negativos que los positivos, aunque éstos no coincidían en importancia. Respecto a los NCP negativos, los pastores no mencionaron la alteración del suelo, los daños a la silvicultura, a la salud humana, las colisiones de tráfico y los conflictos entre colectivos humanos. Consideraron como principales aspectos negativos de los ungulados los daños a la vegetación, la competencia por el pasto, los daños a otros animales de interés económico, los daños agrícolas y la transmisión de enfermedades. Por otro lado, mientras que en las publicaciones la caza deportiva adquiría gran importancia como NCP positivo, los pastores ni siquiera la tuvieron en cuenta, siendo para éstos agentes implicados la regulación de otros organismos el beneficio más importante. Estos resultados pueden tener dos implicaciones. Un mayor énfasis en los NCP negativos puede reforzar la idea de que los ungulados pueden suponer una amenaza para las personas en lugar de contribuir positivamente al bienestar social. El hecho de que las investigaciones no coincidan con los intereses de los pastores puede afectar a la tolerancia social hacia estas especies ya que los daños experimentados o percibidos no son evaluados. Nuestros resultados muestran la relevancia que supone considerar el conocimiento local, en este caso de los pastores, que es uno de los aspectos destacados por el enfoque que hemos tomado, es decir, desde los NCP. Con respecto al Capítulo 3, evaluamos la competencia potencial entre la cabra montés nativa y el arrui exótico estableciendo el solapamiento del nicho en condiciones de coexistencia en la península ibérica. Para ello comparamos el nicho trófico midiendo el contenido de isótopos estables de δ15N y δ13C en pelo, así como el nicho ambiental a partir de modelos de nicho basados en datos de presencia a escala fina. Después evaluamos si ambas especies coocurren espacialmente, o existe segregación espacial como mecanismo de facilitación de coexistencia. Nuestros resultados apuntaron a que ambas especies comparten un nicho trófico y un nicho ambiental similares. Encontramos una asociación espacial negativa entre la cabra montesa y el arrui. Por tanto, las especies son ecológicamente similares y es posible que la segregación espacial detectada favorezca la coexistencia entre ambas en las sierras mediterráneas que cohabitan. Para conocer los efectos de los aportes suplementarios para evitar daños agrícolas, en el Capítulo 4 evaluamos sus efectos en el comportamiento espacial del arrui, así como el uso de los comederos por parte de especies no objetivo de esos aportes. Para ello marcamos nueve arruis con collares GPS/GSM para establecer sus áreas de campeo sin aportes y con aportes, y lo mismo para el número de visitas a los comederos. Después comparamos ese área de campeo estimada y el número de visitas entre periodos para comprobar si hubo variaciones debidas a los aportes. Además, monitoreamos con cámaras de fototrampeo ocho los comederos para identificar que otras especies podían estar haciendo uso de los comederos. Obtuvimos que las áreas de campeo cambiaron para algunos individuos marcados, aunque no todos acudieron a los comederos durante los aportes. El número de visitas a los comederos se incrementó durante los aportes suplementarios. Identificamos a quince especies no objetivo que acudían a los comederos, especialmente el jabalí. Los arruis y los jabalíes mostraron una segregación temporal en cuanto al uso de los comederos. Nuestros resultados sugieren que la efectividad de los aportes suplementarios es limitada en cuanto al comportamiento espacial del arrui, por lo que la reducción de daños agrícolas es limitada. Continuando con los aportes suplementarios como herramienta de gestión evaluada, en el Capítulo 5, evaluamos los efectos de esta herramienta sobre el suelo de un área montañosa de clima mediterráneo. Evaluamos este aspecto porque las propiedades fisicoquímicas y biológicas del suelo pueden verse alteradas debido a la concentración de la fauna silvestre donde se deposita la comida suplementaria. Para ello tomamos muestras de suelo de tres comederos y comparamos las características del suelo entre tres áreas: suelo de los comederos, suelo de alrededor de los comederos, y un suelo de referencia no alterado por los comederos. Nuestros resultados sugirieron que las propiedades físicas del suelo no se veían afectadas en los comederos. Sin embargo, la conductividad eléctrica, la concentración de nutrientes, la actividad microbiana y las comunidades microbianas en los comederos sí se alteraron debido a los aportes y la concentración de fauna, siendo los efectos alrededor de los comederos más débiles. La dinámica edáfica pudo verse modificada debido a estas alteraciones detectadas y contribuir al cambio global. Finalmente, en el Capítulo 6 discutimos los resultados obtenidos en los capítulos previos, abordando también las limitaciones de cada uno, las implicaciones para la conservación de la biodiversidad y las perspectivas futuras sobre la relación entre los ungulados silvestres y los humanosEcosystem functioning includes all cycling materials and energy, the interactions among organisms and the abiotic system. This functioning has been modified due to human activities, especially the biodiversity, which has provoked alterations of interactions among species. Currently the scientific community has recognized a biodiversity crisis because of human activities, which could affect negatively to human wellbeing by means of losing ecosystems and its components. All those benefits that people obtain from ecosystems are ecosystem services (ES), as for example food, tools, maintenance of habitats or even cultural aspects. Historically, our species has been linked to many species and among them ungulates deserve a chapter of their own. Ungulates are animal species closely related with human societies. Relations between humans and wild ungulates vary depending of the context. In developing countries ungulate populations are declining whereas in developed countries they are increasing in abundance and distribution. This rewilding process has contributed to the rise negative interactions between humans and between wild ungulates, as for example agriculture or silviculture damage. To avoid or mitigate these conflicts people use different management tools such as fencing or supplementary feeding. So, research about ungulates and their relations with people should be done from a social-ecological perspective. This thesis focuses on the human-ungulate relations, both positive and negative interactions, and the evaluation of management tools employed to mitigate those negative impacts. Specifically this thesis aims to assess: i) the state of the art of research in human-ungulates relations (Chapter 1); ii) the services and disservices provided by wild ungulates for two stakeholders: scientists and shepherds (Chapter 2); the niche overlap and potential competition between the native Iberian ibex (Capra pyrenaica) and the exotic aoudad (Ammotragus lervia) as a paradigm of conservation conflict (Chapter 3); the effects of supplementary feeding effects on the target species (aoudad), other non-target species and soil properties (Chapters 4 and 5). Finally, in Chapter 6, the results of previous chapters are discussed. First (Chapter 1), we reviewed scientific publications to establish the state of the art about human-ungulate relations. We showed that most scientific publications approach this relations from the perspective of conflicts, being the ES less considered in that studies. Also, most of the publications included environmental managers and hunters as the main social actors regarding human-ungulate relations. Moreover, management tools employed to mitigate ungulate damages to human interests rarely were evaluated, and lethal control and the use of barriers were the main strategies recommended to mitigate or avoid damages. In Chapter 2, we approached to the human-ungulate interactions from the perspective of researchers and shepherds and the framework of ecosystem services based on the categories of beneficial nature’s contributions to people (NCP; Díaz et al., 2018) . We examined and compared scientific research and shepherds’ perceptions regarding the provision of NCP by wild ungulates. We reviewed scientific articles of NCP provided by ungulates in Spain and conducted questionnaires regarding NCP to shepherds in farming systems of Spain where domestic and wild ungulates cohabit. Then, we compared whether the scientific priorities match with those perceived by shepherds. Both stakeholders highlighted more detrimental than beneficial NCP, there were some mismatches between scientific priorities and shepherds’ perceptions. Regarding detrimental NCP, soil alteration, damage to silviculture, human safety, traffic collision and human-human conflicts were frequently studied but not mentioned by shepherds. In contrast, shepherds mainly considered vegetation damage, grazing competence, damage to animals with economic interests, crop damage and disease transmission to livestock as important detrimental NCP. Concerning beneficial NCP, whilst hunting was prominent in the publications, shepherds did not conceived it as an important beneficial contribution and considered the regulation of other organisms as an important benefit. These results can have twofold implications. The emphasis on detrimental NCP can reinforce the idea that ungulates can threaten humans rather than contribute to societies’ wellbeing. The fact that research does not address the interests of shepherds can affect the social tolerance towards ungulates as the damages experienced or perceived by shepherds are not studied. Our results show the relevance of considering local knowledge systems of shepherds, something highlighted by the NCP approach. Regarding Chapter 3, we evaluated the potential competition between the native Iberian ibex and the exotic aoudad measuring the niche overlap under cohabit conditions in the Iberian Peninsula. To do that, we compared the trophic niche by using the content of stable isotopes δ15N and δ13C in the hair, and the environmental niche by modelling habitat based on fine-scale presence records. Then we assessed both species’ co-occurrence to test for spatial segregation. Our results indicated that both species shared a similar trophic niche, showed a similar distribution of suitable areas and that their environmental niches were similar. Moreover, negative spatial association was found between the aoudad and Iberian ibex. So, both species are ecologically similar and suggest that spatial segregation might have favoured their co-existence in semiarid Mediterranean mountains where they cohabit. In order to clarify the effect of diversionary feeding (i.e. specific use of supplementary feeding to avoid crop damage), in Chapter 4 we evaluated its effect in the spatial behaviour of the aoudad. Also, we assessed the use of the diversionary feeding stations (DFS) by non-target species. Nine aoudads were tracked with GPS/GSM collars to establish their home ranges and the visits to the DFS. We compared the home ranges and the number of GPS locations in the DFS before and meanwhile food was available at them. Moreover, eight DFS were monitored with camera traps to identify which other species used the DFS. We found that home ranges varied for some individuals and that not all the tracked animals used the DFS. The number of locations in the DFS increased when food was available. Furthermore, other fifteen non-target species of birds and mammals used DFS, especially the wild boar. Aoudads and wild boars segregated temporally in their use of the DFS. These results suggest that diversionary feeding had little effect on the spatial behaviour of the aoudad and benefited other conflictive species. Continuing with the diversionary feeding as a management tool, we evaluated the effect of this tool on semiarid Mediterranean mountain soils, because physicochemical and biological soil properties can be altered due to the concentration of wildlife in areas where food is deposited (Chapter 5). We collected soil samples from three DFS and compared soil characteristics from three areas: feeding stations (FS), contour area (C; surrounding the feeding stations) and a reference soil (RS; not influenced by feeding stations). Our results suggested no effects on soil physical properties. However, we found that diversionary feeding altered electrical conductivity, nutrient concentration, microbial activity and microbial communities at FS, but effects were weaker in the C. Soil functionality could change due to these alterations of soil dynamics. Finally, Chapter 6 discusses the results presented in this thesis, the limitations of each chapter and the biodiversity conservation implications and future perspectives about wild ungulates and human relations

    Three essays on internal migration and nutrition in Tanzania

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    This thesis is formed of three separate essays. The essays are empirical in nature and use the Kagera Health and Development Survey from Tanzania. The survey spans a 19-year period offering a unique opportunity to study many long-run dynamic processes of development in rural Africa. In the first essay, a version of which was co-authored with Joachim De Weerdt, we use these data to shed light on how mass internal migration changes the nature of informal risk-sharing. By quantifying how shocks and consumption co-move across linked households, our analysis shows that migrants unilaterally insure their extended family members who remain at home. This finding contradicts risk-sharing models based on reciprocity, but is consistent with assistance driven by social norms. Migrants sacrifice three to five per cent of their consumption growth to provide this insurance, which seems too trivial to have a stifling effect on their growth through migration. The second essay studies the role of exogenous income shocks on long-term migration decisions. The results reveal that temperature shocks cause large fluctuations in household consumption and inhibit long-term migration among men. These findings suggest that liquidity constraints are binding and prevent potential migrants from tapping into the opportunities brought about by internal migration. The final essay focuses on child nutrition and examines whether under-nourished children are able to recover the height losses later in life. The essay questions the methods used in the existing empirical literature and challenges the conventional view that recovery is nearly impossible after five years of age. The empirical part of the essay documents how puberty offers an opportunity window for recovery in the case of children in Kagera

    Determination of Time Dependent Stress Distribution on Potato Tubers at Mechanical Collision

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    This study focuses on determining internal stress progression and the realistic representation of time dependent deformation behaviour of potato tubers under a sample mechanical collision case. A reverse engineering approach, physical material tests and finite element method (FEM)-based explicit dynamics simulations were utilised to investigate the collision based deformation characteristics of the potato tubers. Useful numerical data and deformation visuals were obtained from the simulation results. The numerical results are presented in a format that can be used for the determination of bruise susceptibility magnitude on solid-like agricultural products. The modulus of elasticity was calculated from experimental data as 3.12 [MPa] and simulation results showed that the maximum equivalent stress was 1.40 [MPa] and 3.13 [MPa] on the impacting and impacted tubers respectively. These stress values indicate that bruising is likely on the tubers. This study contributes to further research on the usage of numerical-methods-based nonlinear explicit dynamics simulation techniques in complicated deformation and bruising investigations and industrial applications related to solid-like agricultural products

    Evaluating the sustainability of urban agriculture projects

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    Evaluating the sustainability of urban agriculture projects. 5. International Symposium for Farming Systems Design (AGRO2015

    The Nexus Between Security Sector Governance/Reform and Sustainable Development Goal-16

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    This Security Sector Reform (SSR) Paper offers a universal and analytical perspective on the linkages between Security Sector Governance (SSG)/SSR (SSG/R) and Sustainable Development Goal-16 (SDG-16), focusing on conflict and post-conflict settings as well as transitional and consolidated democracies. Against the background of development and security literatures traditionally maintaining separate and compartmentalized presence in both academic and policymaking circles, it maintains that the contemporary security- and development-related challenges are inextricably linked, requiring effective measures with an accurate understanding of the nature of these challenges. In that sense, SDG-16 is surely a good step in the right direction. After comparing and contrasting SSG/R and SDG-16, this SSR Paper argues that human security lies at the heart of the nexus between the 2030 Agenda of the United Nations (UN) and SSG/R. To do so, it first provides a brief overview of the scholarly and policymaking literature on the development-security nexus to set the background for the adoption of The Agenda 2030. Next, it reviews the literature on SSG/R and SDGs, and how each concept evolved over time. It then identifies the puzzle this study seeks to address by comparing and contrasting SSG/R with SDG-16. After making a case that human security lies at the heart of the nexus between the UN’s 2030 Agenda and SSG/R, this book analyses the strengths and weaknesses of human security as a bridge between SSG/R and SDG-16 and makes policy recommendations on how SSG/R, bolstered by human security, may help achieve better results on the SDG-16 targets. It specifically emphasizes the importance of transparency, oversight, and accountability on the one hand, and participative approach and local ownership on the other. It concludes by arguing that a simultaneous emphasis on security and development is sorely needed for addressing the issues under the purview of SDG-16

    Big Data in Bioeconomy

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    This edited open access book presents the comprehensive outcome of The European DataBio Project, which examined new data-driven methods to shape a bioeconomy. These methods are used to develop new and sustainable ways to use forest, farm and fishery resources. As a European initiative, the goal is to use these new findings to support decision-makers and producers – meaning farmers, land and forest owners and fishermen. With their 27 pilot projects from 17 countries, the authors examine important sectors and highlight examples where modern data-driven methods were used to increase sustainability. How can farmers, foresters or fishermen use these insights in their daily lives? The authors answer this and other questions for our readers. The first four parts of this book give an overview of the big data technologies relevant for optimal raw material gathering. The next three parts put these technologies into perspective, by showing useable applications from farming, forestry and fishery. The final part of this book gives a summary and a view on the future. With its broad outlook and variety of topics, this book is an enrichment for students and scientists in bioeconomy, biodiversity and renewable resources
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