7,151 research outputs found
Benefits of Bullying? A Test of the Evolutionary Hypothesis in Three Cohorts
Recent work on bullying perpetration includes the hypothesis that bullying carries an evolutionary advantage for perpetrators in terms of health and reproductive success. We tested this hypothesis in the National Child Development Study (n = 4998 male, n = 4831 female), British Cohort Study 1970 (n = 4261 male, n = 4432 female), and TRacking Adolescentsâ Individual Lives Survey (n = 486 male, n = 521 female), where bullying was assessed in adolescence (NCDS, BCS70: age 16, TRAILS: age 14) and outcomes in adulthood. Partial support for the evolutionary hypothesis was found as bullies had more children in NCDS and engaged in sexual intercourse earlier in TRAILS. In contrast, bullies reported worse health in NCDS and BCS70
Identifying and prioritising services in European terrestrial and freshwater ecosystems
Ecosystems are multifunctional and provide humanity with a broad array of vital services. Effective management of services requires an improved evidence base, identifying the role of ecosystems in delivering multiple services, which can assist policy-makers in maintaining them. Here, information from the literature and scientific experts was used to systematically document the importance of services and identify trends in their use and status over time for the main terrestrial and freshwater ecosystems in Europe. The results from this review show that intensively managed ecosystems contribute mostly to vital provisioning services (e.g. agro-ecosystems provide food via crops and livestock, and forests provide wood), while semi-natural ecosystems (e.g. grasslands and mountains) are key contributors of genetic resources and cultural services (e.g. aesthetic values and sense of place). The most recent European trends in human use of services show increases in demand for crops from agro-ecosystems, timber from forests, water flow regulation from rivers, wetlands and mountains, and recreation and ecotourism in most ecosystems, but decreases in livestock production, freshwater capture fisheries, wild foods and virtually all services associated with ecosystems which have considerably decreased in area (e.g. semi-natural grasslands). The condition of the majority of services show either a degraded or mixed status across Europe with the exception of recent enhancements in timber production in forests and mountains, freshwater provision, water/erosion/natural hazard regulation and recreation/ecotourism in mountains, and climate regulation in forests. Key gaps in knowledge were evident for certain services across all ecosystems, including the provision of biochemicals and natural medicines, genetic resources and the regulating services of seed dispersal, pest/disease regulation and invasion resistance
Recommended from our members
Local search: A guide for the information retrieval practitioner
There are a number of combinatorial optimisation problems in information retrieval in which the use of local search methods are worthwhile. The purpose of this paper is to show how local search can be used to solve some well known tasks in information retrieval (IR), how previous research in the field is piecemeal, bereft of a structure and methodologically flawed, and to suggest more rigorous ways of applying local search methods to solve IR problems. We provide a query based taxonomy for analysing the use of local search in IR tasks and an overview of issues such as fitness functions, statistical significance and test collections when conducting experiments on combinatorial optimisation problems. The paper gives a guide on the pitfalls and problems for IR practitioners who wish to use local search to solve their research issues, and gives practical advice on the use of such methods. The query based taxonomy is a novel structure which can be used by the IR practitioner in order to examine the use of local search in IR
Personalised video retrieval: application of implicit feedback and semantic user profiles
A challenging problem in the user profiling domain is to create profiles of users of retrieval systems. This problem even exacerbates in the multimedia domain. Due to the Semantic Gap, the difference between low-level data representation of videos and the higher concepts users associate with videos, it is not trivial to understand the content of multimedia documents and to find other documents that the users might be interested in. A promising approach to ease this problem is to set multimedia documents into their semantic contexts. The semantic context can lead to a better understanding of the personal interests. Knowing the context of a video is useful for recommending users videos that match their information need. By exploiting these contexts, videos can also be linked to other, contextually related videos. From a user profiling point of view, these
links can be of high value to recommend semantically related videos, hence creating a semantic-based user profile. This thesis introduces a semantic user profiling approach for news video retrieval, which exploits a generic ontology to put news stories into its context.
Major challenges which inhibit the creation of such semantic user profiles are the identification of user's long-term interests and the adaptation of retrieval results based on these personal interests. Most personalisation services rely on users explicitly specifying preferences, a common approach in the text retrieval domain. By giving explicit feedback, users are forced to update their need, which can be problematic when their information need is vague. Furthermore, users tend not to provide enough feedback on which to base an adaptive retrieval algorithm. Deviating from the method of explicitly asking the user to rate the relevance of retrieval results, the use of implicit feedback techniques helps by learning user interests unobtrusively. The main advantage is that users are relieved from providing feedback. A disadvantage is that information gathered using implicit techniques is less accurate than information based on explicit feedback.
In this thesis, we focus on three main research questions. First of all, we study whether implicit relevance feedback, which is provided while interacting with a video retrieval system, can be employed to bridge the Semantic Gap. We therefore first identify implicit indicators of relevance by analysing representative video retrieval interfaces.
Studying whether these indicators can be exploited as implicit feedback within short retrieval sessions, we recommend video documents based on implicit actions performed by a community of users. Secondly, implicit relevance feedback is studied as potential source to build user profiles and hence to identify users' long-term interests in specific topics. This includes studying the identification of different aspects of interests
and storing these interests in dynamic user profiles. Finally, we study how this feedback can be exploited to adapt retrieval results or to recommend related videos
that match the users' interests. We analyse our research questions by performing both simulation-based and user-centred evaluation studies. The results suggest that implicit relevance feedback can be employed in the video domain and that semantic-based user profiles have the potential to improve video exploration
LinkedScales : bases de dados em multiescala
Orientador: AndrĂŠ SantanchèTese (doutorado) - Universidade Estadual de Campinas, Instituto de ComputaçãoResumo: As ciĂŞncias biolĂłgicas e mĂŠdicas precisam cada vez mais de abordagens unificadas para a anĂĄlise de dados, permitindo a exploração da rede de relacionamentos e interaçþes entre elementos. No entanto, dados essenciais estĂŁo frequentemente espalhados por um conjunto cada vez maior de fontes com mĂşltiplos nĂveis de heterogeneidade entre si, tornando a integração cada vez mais complexa. Abordagens de integração existentes geralmente adotam estratĂŠgias especializadas e custosas, exigindo a produção de soluçþes monolĂticas para lidar com formatos e esquemas especĂficos. Para resolver questĂľes de complexidade, essas abordagens adotam soluçþes pontuais que combinam ferramentas e algoritmos, exigindo adaptaçþes manuais. Abordagens nĂŁo sistemĂĄticas dificultam a reutilização de tarefas comuns e resultados intermediĂĄrios, mesmo que esses possam ser Ăşteis em anĂĄlises futuras. AlĂŠm disso, ĂŠ difĂcil o rastreamento de transformaçþes e demais informaçþes de proveniĂŞncia, que costumam ser negligenciadas. Este trabalho propĂľe LinkedScales, um dataspace baseado em mĂşltiplos nĂveis, projetado para suportar a construção progressiva de visĂľes unificadas de fontes heterogĂŞneas. LinkedScales sistematiza as mĂşltiplas etapas de integração em escalas, partindo de representaçþes brutas (escalas mais baixas), indo gradualmente para estruturas semelhantes a ontologias (escalas mais altas). LinkedScales define um modelo de dados e um processo de integração sistemĂĄtico e sob demanda, atravĂŠs de transformaçþes em um banco de dados de grafos. Resultados intermediĂĄrios sĂŁo encapsulados em escalas reutilizĂĄveis e transformaçþes entre escalas sĂŁo rastreadas em um grafo de proveniĂŞncia ortogonal, que conecta objetos entre escalas. Posteriormente, consultas ao dataspace podem considerar objetos nas escalas e o grafo de proveniĂŞncia ortogonal. Aplicaçþes prĂĄticas de LinkedScales sĂŁo tratadas atravĂŠs de dois estudos de caso, um no domĂnio da biologia -- abordando um cenĂĄrio de anĂĄlise centrada em organismos -- e outro no domĂnio mĂŠdico -- com foco em dados de medicina baseada em evidĂŞnciasAbstract: Biological and medical sciences increasingly need a unified, network-driven approach for exploring relationships and interactions among data elements. Nevertheless, essential data is frequently scattered across sources with multiple levels of heterogeneity. Existing data integration approaches usually adopt specialized, heavyweight strategies, requiring a costly upfront effort to produce monolithic solutions for handling specific formats and schemas. Furthermore, such ad-hoc strategies hamper the reuse of intermediary integration tasks and outcomes. This work proposes LinkedScales, a multiscale-based dataspace designed to support the progressive construction of a unified view of heterogeneous sources. It departs from raw representations (lower scales) and goes towards ontology-like structures (higher scales). LinkedScales defines a data model and a systematic, gradual integration process via operations over a graph database. Intermediary outcomes are encapsulated as reusable scales, tracking the provenance of inter-scale operations. Later, queries can combine both scale data and orthogonal provenance information. Practical applications of LinkedScales are discussed through two case studies on the biology domain -- addressing an organism-centric analysis scenario -- and the medical domain -- focusing on evidence-based medicine dataDoutoradoCiĂŞncia da ComputaçãoDoutor em CiĂŞncia da Computação141353/2015-5CAPESCNP
Hikers' attitudes to the National Hikingway system in the south-western Cape
Includes bibliography.This research report sets out to determine the trail facility preferences (social carrying capacity) for National Hikingway trails in the south-western Cape. It was found that social carrying capacity is a complex concept, based on perceptive experiences and relative social values. It is not so much the level of use that determines SCC, but a user's perceptions of types and levels of use that are apparent in a recreation area. The major line of investigation was a cross-sectional attitude study to ascertain trail facility preferences of mountaineers in the study area: the first step was to the establish the social milieu of mountaineering in order to place the research in an ethical and historical context; next, the literature on outdoor recreation was reviewed and the major trends in research identified in an attempt to place the research in a methodological paradigm; thirdly, the overview and principles established in steps 1 and 2 of the report were used to develop an attitude survey on NHW trail facility preferences. While a range of preferences was found to exist, it was found to be more supportive of the status quo than expected. An anticipated gradation of preferences according to one's level of hiking experience was not statistically supported by sub-group analysis. The survey results emphasise the importance of evaluating conceptual perspectives with empirical analyses. Social and ecological interests are best served by providing a range of trail types characterised by various trail facilities, to cater for high and low carrying capacity preferences. Trail management should consider traditional recreational uses in an area, current land uses and the future needs of mountaineers in the region
- âŚ