1,282 research outputs found

    Ward's Hierarchical Clustering Method: Clustering Criterion and Agglomerative Algorithm

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    The Ward error sum of squares hierarchical clustering method has been very widely used since its first description by Ward in a 1963 publication. It has also been generalized in various ways. However there are different interpretations in the literature and there are different implementations of the Ward agglomerative algorithm in commonly used software systems, including differing expressions of the agglomerative criterion. Our survey work and case studies will be useful for all those involved in developing software for data analysis using Ward's hierarchical clustering method.Comment: 20 pages, 21 citations, 4 figure

    Oregon, My Oregon

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    https://digitalcommons.library.umaine.edu/mmb-vp/5723/thumbnail.jp

    Mumford dendrograms and discrete p-adic symmetries

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    In this article, we present an effective encoding of dendrograms by embedding them into the Bruhat-Tits trees associated to pp-adic number fields. As an application, we show how strings over a finite alphabet can be encoded in cyclotomic extensions of Qp\mathbb{Q}_p and discuss pp-adic DNA encoding. The application leads to fast pp-adic agglomerative hierarchic algorithms similar to the ones recently used e.g. by A. Khrennikov and others. From the viewpoint of pp-adic geometry, to encode a dendrogram XX in a pp-adic field KK means to fix a set SS of KK-rational punctures on the pp-adic projective line P1\mathbb{P}^1. To P1∖S\mathbb{P}^1\setminus S is associated in a natural way a subtree inside the Bruhat-Tits tree which recovers XX, a method first used by F. Kato in 1999 in the classification of discrete subgroups of PGL2(K)\textrm{PGL}_2(K). Next, we show how the pp-adic moduli space M0,n\mathfrak{M}_{0,n} of P1\mathbb{P}^1 with nn punctures can be applied to the study of time series of dendrograms and those symmetries arising from hyperbolic actions on P1\mathbb{P}^1. In this way, we can associate to certain classes of dynamical systems a Mumford curve, i.e. a pp-adic algebraic curve with totally degenerate reduction modulo pp. Finally, we indicate some of our results in the study of general discrete actions on P1\mathbb{P}^1, and their relation to pp-adic Hurwitz spaces.Comment: 14 pages, 6 figure

    Moral, wasteful, frugal, or thrifty? Identifying consumer identities to understand and manage pro-environmental behaviour

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    Moral motives are important for pro-environmental behavior. But such behavior is not only motivated by moral or environmental concerns. We examined what higher order motives, other than morality, may be important for understanding pro-environmental behavior, by studying consumer identities. In three studies (N = 877) four consumer identities were distinguished: moral, wasteful, frugal, and thrifty. Frugal and moral consumer identities were most salient and were the strongest predictors of pro-environmental behaviors, but in different ways. Frugality, which is related to, but distinct from thriftiness, was particularly important for behaviors associated with waste reduction of any kind (including money). The findings suggest that people adopt the same behavior for different reasons, in ways consistent with their consumer identities. People manage multiple consumer identities simultaneously, and environmental policy is likely to be more effective if it addresses these multiple identities

    Does perception of automation undermine pro-environmental behaviour? Findings from three everyday settings

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    The global deployment of technology to aid mitigation of climate change has great potential but the realisation of much of this potential depends on behavioural response. A culturally pervasive reliance on and belief in technology raises the risk that dependence on technology will hamper human actions of mitigation. Theory suggests that ‘green’ behaviour may be undermined by automated technology but empirical investigation has been lacking. We examined the effect of the prospect of automation on three everyday behaviours with environmental impact. Based on evidence from observational and experimental studies, we demonstrated that the prospect of automation can undermine even simple actions for sustainability. Further, we examined the process by which automated technology influences behaviour and suggest that automation may impair personal responsibility for action

    First Odin sub-mm retrievals in the tropical upper troposphere: ice cloud properties

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    International audienceMore accurate global measurements of the amount of ice in thicker clouds are needed to validate atmospheric models and sub-mm radiometry can be an important component in this respect. A cloud ice retrieval scheme for the first such instrument in space, Odin-SMR, is presented here. Several advantages of sub-mm observations are shown, such as low influence of particle shape and orientation, and a high dynamic range of the retrievals. In the case of Odin-SMR, only cloud ice above ?12.5 km can be measured. The present retrieval scheme gives a detection threshold of about 4 g/m2 above 12.5 km and does not saturate even for thickest observed clouds (>500 g/m2). The main retrieval uncertainties are the assumed particle size distribution and cloud inhomogeneity effects. The overall retrieval accuracy is estimated to be ~75%. The retrieval error is judged to have large random components and to be significantly lower than this value for averaged results, but high fixed errors can not be excluded. However, a firm lower value can always be provided. Initial results are found to be consistent with similar Aura MLS retrievals, but show important differences to corresponding data from atmospheric models. This first retrieval algorithm is limited to lowermost Odin-SMR tangent altitudes, and further development should improve the detection threshold and the vertical resolution. It should also be possible to decrease the retrieval uncertainty associated with cloud inhomogeneities by detailed analysis of other data sets

    Expansion and Rehabilitation of the State Fish Pier in Gloucester, Massachusetts

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    The State Fish Pier in Gloucester, Massachusetts, has been expanded and rehabilitated to provide an upgraded facility to support the local fishing industry. Expansion consisted of a new Finger Pier and solid fill extension of the existing pier. Rehabilitation consisted of replacing a deteriorated wharf with a new higher load carrying wharf. Subsurface conditions ranged from rock outcrops exposed at low tide at some locations to thick marine deposits overlying rock at other locations. Foundation support for the new Finger Pier and rehabilitated wharf consisted of concrete filled steel pipe piles, a portion of which had to he socketed into bedrock due to lack of soil overburden. Compression and tension load tests were performed to verify the pile design capacities

    How many people will need palliative care in 2040? Past trends, future projections and implications for services.

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    BACKGROUND: Current estimates suggest that approximately 75% of people approaching the end-of-life may benefit from palliative care. The growing numbers of older people and increasing prevalence of chronic illness in many countries mean that more people may benefit from palliative care in the future, but this has not been quantified. The present study aims to estimate future population palliative care need in two high-income countries. METHODS: We used mortality statistics for England and Wales from 2006 to 2014. Building on previous diagnosis-based approaches, we calculated age- and sex-specific proportions of deaths from defined chronic progressive illnesses to estimate the prevalence of palliative care need in the population. We calculated annual change over the 9-year period. Using explicit assumptions about change in disease prevalence over time, and official mortality forecasts, we modelled palliative care need up to 2040. We also undertook separate projections for dementia, cancer and organ failure. RESULTS: By 2040, annual deaths in England and Wales are projected to rise by 25.4% (from 501,424 in 2014 to 628,659). If age- and sex-specific proportions with palliative care needs remain the same as in 2014, the number of people requiring palliative care will grow by 25.0% (from 375,398 to 469,305 people/year). However, if the upward trend observed from 2006 to 2014 continues, the increase will be of 42.4% (161,842 more people/year, total 537,240). In addition, disease-specific projections show that dementia (increase from 59,199 to 219,409 deaths/year by 2040) and cancer (increase from 143,638 to 208,636 deaths by 2040) will be the main drivers of increased need. CONCLUSIONS: If recent mortality trends continue, 160,000 more people in England and Wales will need palliative care by 2040. Healthcare systems must now start to adapt to the age-related growth in deaths from chronic illness, by focusing on integration and boosting of palliative care across health and social care disciplines. Countries with similar demographic and disease changes will likely experience comparable rises in need
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