1,095,567 research outputs found

    A semi-parametric approach to estimate risk functions associated with multi-dimensional exposure profiles: application to smoking and lung cancer

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    A common characteristic of environmental epidemiology is the multi-dimensional aspect of exposure patterns, frequently reduced to a cumulative exposure for simplicity of analysis. By adopting a flexible Bayesian clustering approach, we explore the risk function linking exposure history to disease. This approach is applied here to study the relationship between different smoking characteristics and lung cancer in the framework of a population based case control study

    Arthroscopic patterns of the poster-medial aspect of the knee joint: classification of the gastrocnemius-semimembranosus gateway and its relationship with Baker's cyst

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    Background The gastrocnemius-semimembranosus bursa may communicate with the knee joint. The arthroscopic anatomy of the posteromedial aspect varies depending on the angle of the oblique popliteal ligament, the level at which it crosses the medial gastrocnemius tendon, and its relationship with the capsular joint and synovia. The aim of this paper is to identify possible patterns, and to evaluate their characteristics and their relationship with Baker’s cyst. Methods data archived from 185 consecutive arthroscopies were evaluated; an anatomic description and classification was carried out; the percentages of association with BC and the associated pathologies were reported. Results The different anatomies were classified into six groups based on the relationship above the medial gastrocnemius tendon, the capsular joint and synovia. The prevalence of Baker’s cyst was 28.3%. The main associated intra-articular pathological condition was the contemporary presence of a meniscal tear and chondropathy. Conclusion Exploration of the posterior aspect of the knee must be performed routinely. Knowing the possible anatomy patterns of the posteromedial arthroscopic aspect of the knee joint could help to identify the cyst and its gateway, thus facilitating its treatment

    A framework for knowledge – Driven CRM

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    In this paper we propose a framework to combine KDD (Knowledge Discovered in Databases) and CRM (Customer Relationship Management), with an emphasis on customer retention. The key aspect of the proposed framework is to enable adaptive use of knowledge discovered to predict customer buying patterns and capture interesting knowledge about customers

    Music Preferences and Behavoural Patterns of Adolescents in Enugu Town, Nigeria: Implications for Development

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    Music which is reflective of the values and attitude of a society, constitutes an important aspect of life of the adolescents and consequently takes up an important portion of their time. It not only forms part of the medium through which many morally decadent concepts and values are expressed and disseminated, but also proffers music technological tools for combating many social ills. This research aims to ascertain whether, and to what extent preference of musical styles affect behavioural patterns that influence human development in adolescents. Employing quantitative and qualitative approaches, this study investigates the relationship between musical preferences and behavioural patterns of adolescents between the ages of fourteen and nineteen resident in Enugu town. It observes a significant relationship between musical content and corresponding behavioural patterns among adolescents in Enugu. It argues that behavioural patterns influence the means and rate of development. Keywords: Implication, Music preferences, Behavioural patterns, Development, Adolescents

    Graded cluster algebras

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    In the cluster algebra literature, the notion of a graded cluster algebra has been implicit since the origin of the subject. In this work, we wish to bring this aspect of cluster algebra theory to the foreground and promote its study. We transfer a definition of Gekhtman, Shapiro and Vainshtein to the algebraic setting, yielding the notion of a multi-graded cluster algebra. We then study gradings for finite type cluster algebras without coefficients, giving a full classification. Translating the definition suitably again, we obtain a notion of multi-grading for (generalised) cluster categories. This setting allows us to prove additional properties of graded cluster algebras in a wider range of cases. We also obtain interesting combinatorics---namely tropical frieze patterns---on the Auslander--Reiten quivers of the categories.Comment: 23 pages, 6 figures. v2: Substantially revised with additional results. New section on graded (generalised) cluster categories. v3: added Prop. 5.5 on relationship with Grothendieck group of cluster categor

    A comprehensive study of personal and social information use in female brown-headed cowbirds, Molothrus ater

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    Brood parasites face considerable cognitive challenges when locating and selecting host nests for their young. One aspect of this challenge is determining how to use different sources of information to make decisions regarding the quality of a prospective nest. Here we investigate how female-brown-headed cowbirds, Molothrus ater, use information when prospecting for nests, and then expand upon this to investigate decisions related to foraging. In chapter 1, we demonstrated female could use social information acquired from observing the nest prospecting patterns of conspecifics to influence their own patterns of nest selection. Furthermore, we found a negative relationship between a female’s accuracy at using personal information and her tendency to copy others. In chapter 2, we found the females were able to use social information in a foraging setting as well. The female’s accuracy using personal information remained consistent across nest prospecting and foraging contexts however, the relationship between accuracy and tendency to copy others drastically reversed. A follow up experiment revealed the likely possibility that the differing relationship between personal and social information use depended on the degree of conflict that existed between the two types of information. In chapter 3, we redeveloped and implemented a new RFID tracking technology allowing us to investigate how the cognitive strategies from chapters 1 and 2 translated to a naturalistic, socially complex breeding environment. We found female cowbirds who spent more time prospecting, produced a greater quantity of eggs and demonstrated high accuracy scores during chapter 1 and 2, whereas females who relied on copying others spent significantly less time prospecting and demonstrated lower laying accuracy scores. By demonstrating how individuals’ cognitive strategies relate across context and translate to a socially complex setting, we have demonstrated the importance of examining behaviour in both of these settings and our RFID tracking technology provides researchers with the framework to effectively study this in the future

    The Influence of Geo-Morphological Landscape Patterns on Vegetation Characteristics in Tajikistan Grasslands

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    Grassland ecosystems are affected by a combination of physical and environmental factors, as well as by grazing and human induced activities. The primary objective of this study was to examine the influence of geo-morphological landscape patterns on vegetation characteristics in Tajikistan where two sites were selected. The vegetation sampling took place in spring and fall. Vegetation characteristics were assessed using the line intercept method for vegetation cover and species composition and quadrat sampling for biomass production. An ANOVA using replicated trials in complete block design was used to determine the relationship between aspect and vegetation characteristics. Treatments included location (site), season (fall and spring pastures), and aspect. Site, season and aspect had significant impact on the species composition, cover, and biomass production (P \u3c 0.001). The present study emphasizes the strong relationship between vegetation coverage and surface temperature (potential direct incident radiation). Unfortunately, this parameter has been overlooked in the past and needs to be taken into account when considering options for rehabilitation and restoration measures of degraded grasslands
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