Linear algebra meets Lie algebra: the Kostant-Wallach theory

In two languages, Linear Algebra and Lie Algebra, we describe the results of Kostant and Wallach on the fibre of matrices with prescribed eigenvalues of all leading principal submatrices. In addition, we present a brief introduction to basic notions in Algebraic Geometry, Integrable Systems, and Lie Algebra aimed at specialists in Linear Algebra.Comment: 27 pages, LaTeX; abstract adde

From ‘other’ to involved: User involvement in research: An emerging paradigm

This article has been made available through the Brunel Open Access Publishing Fund. Copyright @ 2013 The Author(s). This is an Open Access article. Non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly attributed, cited, and is not altered, transformed, or built upon in any way, is permitted. The moral rights of the named author(s) have been asserted.This article explores the issue of ‘othering’ service users and the role that involving them, particularly in social policy and social work research may play in reducing this. It takes, as its starting point, the concept of ‘social exclusion’, which has developed in Europe and the marginal role that those who have been included in this construct have played in its development and the damaging effects this may have. The article explores service user involvement in research and is itself written from a service user perspective. It pays particular attention to the ideological, practical, theoretical, ethical and methodological issues that such user involvement may raise for research. It examines problems that both research and user involvement may give rise to and also considers developments internationally to involve service users/subjects of research, highlighting some of the possible implications and gains of engaging service user knowledge in research and the need for this to be evaluated

From qd to LR, or, how were the qd and LR algorithms discovered?

Perhaps, the most astonishing idea in eigenvalue computation is Rutishauser's idea of applying the LR transform to a matrix for generating a sequence of similar matrices that become more and more triangular. The same idea is the foundation of the ubiquitous QR algorithm. It is well known that this idea originated in Rutishauser's qd algorithm, which precedes the LR algorithm and can be understood as applying LR to a tridiagonal matrix. But how did Rutishauser discover qd and when did he find the qd-LR connection? We checked some of the early sources and have come up with an explanatio

Variation in the transfer of radionuclide to freshwater fish: phylogeny or feeding strategy?

For both terrestrial vascular plants and marine organisms if has been demonstrated the differences in radionuclide transfer between species can be related to their evolutionary history or phylogeny. Relationships between phylogeny and radionuclide transfer offer a potential approach to help to derive best estimate values if data for a given species-radionuclide are not available. In this paper we describe the analyses of data for radionuclide transfer to freshwater fish from a data base recently compiled to support activities of both the IAEA and ICRP. There are sufficient data in the database to test the hypothesis that radionuclide transfer can be related to the evolutionary of freshwater fish for caesium, strontium and uranium. For instance, the database contains 750 entries for caesium considering nearly 70 species of fish. Initial results indicate that phylogeny does explain some of the variation in radionuclide transfer between species of fish. However, feeding strategy also explains variation in radionuclide transfer between species. In this paper we will compare our results to establish if phylogeny or feeding strategy is the most useful predictor of radionuclide transfer to freshwater fish

Quantifying Privacy Loss of Human Mobility Graph Topology

Human mobility is often represented as a mobility network, or graph, with nodes representing places of significance which an individual visits, such as their home, work, places of social amenity, etc., and edge weights corresponding to probability estimates of movements between these places. Previous research has shown that individuals can be identified by a small number of geolocated nodes in their mobility network, rendering mobility trace anonymization a hard task. In this paper we build on prior work and demonstrate that even when all location and timestamp information is removed from nodes, the graph topology of an individual mobility network itself is often uniquely identifying. Further, we observe that a mobility network is often unique, even when only a small number of the most popular nodes and edges are considered. We evaluate our approach using a large dataset of cell-tower location traces from 1 500 smartphone handsets with a mean duration of 430 days. We process the data to derive the top−N places visited by the device in the trace, and find that 93% of traces have a unique top−10 mobility network, and all traces are unique when considering top−15 mobility networks. Since mobility patterns, and therefore mobility networks for an individual, vary over time, we use graph kernel distance functions, to determine whether two mobility networks, taken at different points in time, represent the same individual. We then show that our distance metrics, while imperfect predictors, perform significantly better than a random strategy and therefore our approach represents a significant loss in privacy

European bison (Bison bonasus) in the Chornobyl Exclusion Zone (Ukraine) and prospects for its revival

In 2012–2016 a European bison adult bull was observed (by camera traps) in the Chornobyl Exclusion Zone (CEZ, Ukraine), west of Tovstyi Lis village. This is the first record of wild bison in Kyiv Polissya for over 300 years. The animal must have come from the Paliessie State Radioecological Reserve (PSRER, Belarus), having crossed the Pripyat river. The site where he was observed is 30–40 km from the locality where bison were introduced into the PSRER in 1996. The total area over which the bull has been observed is ca. 30–50 km2, and includes deciduous (oak, hornbeam, aspen) and mixed woodlands, and former grassy meadows now overgrown with birch, alder, aspen, pine. This constitutes the most favourable habitat type for bison available in the CEZ. The animal was only observed in February–March and August–October. Currently we are not able to judge how permanently the animal stays on this territory. Taking into account the amount of appropriate habitat in the region, size of the CEZ, protection regime and the fact that bison was a native species in the past, the CEZ could be the best area in Ukraine where a large free population of the European bison could be established.У 2012–2016 рр. за допомогою фотопасток спостерігали дорослого бика зубра у Чорнобильській зоні відчуження (ЧЗВ, Україна), західніше с. Товстий Ліс. Це перша реєстрація вільного зубра у Київському Поліссі за останні 300 років. Тварина мала прийти з Поліського державного радіоекологічного заповідника (ПДРЕЗ, Білорусь), перетнувши р. Прип’ять. Ділянка спостережень знаходиться у 30–40 км від місця, де зубрів інтродукували у ПДРЕЗ у 1996 р. Загальна її площа складає близько 30–50 км2 і включає широколистяні (дуб, граб, осика) і мішані ліси та колишні вологі луки, що зараз поросли березою, вільхою, осикою, сосною. Це найсприятливіші для зубра угіддя у ЧЗВ. Тварину спостерігали лише у лютому–березні та серпні–жовтні. Зараз бракує даних, щоб судити наскільки тварина постійно тримається ділянки. Приймаючи до уваги кількість угідь, що відповідають потребам зубра, розмір ЧЗВ, охоронний режим та той факт, що колись це був автохтонний вид, ЧЗВ могла б стати найкращим місцем в Україні, де можна було б створити велику вільну популяцію зубра

Ethical dilemmas are not simply black and white

This is an Accepted Manuscript of an article published by Taylor & Francis Group in Ethics and Social Practice on 1 July 2008, available online at: http://dx.doi.org/10.1080/17496530801948838.This article aims to highlight some of the ethical issues that arise when social work educators plan to involve service users and carers from black and minority ethnic (BME) communities in the teaching of social work students. Between 2005 and 2007, the authors carried out a two-part project that involved working with service users and carers from BME communities in the area around Liverpool in Britain. The article first discusses the background for this two-part project, highlighting two themes relating to the ethical dilemmas we experienced. The first of these themes concerned conducting a project in a political context based on short and intermittent funding and intransigent bureaucracy. Our second theme concerned how to reconcile bringing together a group of people because they were recognized as having a shared experience while at the same time there were a myriad differences within the group. We then discuss these issues in light of the ethical approach we adopted, based on being open and honest, flexible in a respectful and meaningful way, and on anti-oppressive ethics and shared responsibility.Peer reviewe