665 research outputs found
{YAGO}2: A Spatially and Temporally Enhanced Knowledge Base from {Wikipedia}
We present YAGO2, an extension of the YAGO knowledge base, in which entities, facts, and events are anchored in both time and space. YAGO2 is built automatically from Wikipedia, GeoNames, and WordNet. It contains 80 million facts about 9.8 million entities. Human evaluation confirmed an accuracy of 95\% of the facts in YAGO2. In this paper, we present the extraction methodology, the integration of the spatio-temporal dimension, and our knowledge representation SPOTL, an extension of the original SPO-triple model to time and space
A mineralogical record of ocean change: decadal and centennial patterns in the California mussel
Ocean acidification, a product of increasing atmospheric carbon dioxide, may already have affected calcified organisms in the coastal zone, such as bivalves and other shellfish. Understanding species’ responses to climate change requires the context of long-term dynamics. This can be particularly difficult given the longevity of many important species in contrast with the relatively rapid onset of environmental changes. Here, we present a unique archival dataset of mussel shells from a locale with recent environmental monitoring and historical climate reconstructions. We compare shell structure and composition in modern mussels, mussels from the 1970s, and mussel shells dating back to 1000–2420 years BP. Shell mineralogy has changed dramatically over the past 15 years, despite evidence for consistent mineral structure in the California mussel, Mytilus californianus, over the prior 2500 years. We present evidence for increased disorder in the calcium carbonate shells of mussels and greater variability between individuals. These changes in the last decade contrast markedly from a background of consistent shell mineralogy for centuries. Our results use an archival record of natural specimens to provide centennial-scale context for altered minerology and variability in shell features as a response to acidification stress and illustrate the utility of long-term studies and archival records in global change ecology. Increased variability between individuals is an emerging pattern in climate change responses, which may equally expose the vulnerability of organisms and the potential of populations for resilience
Evaluation of a Required Senior Research Project in a Doctor of Pharmacy Curriculum
Objective. To characterize the dissemination of study findings and assess project preceptor attitudes towards a required senior research project in a doctor of pharmacy (PharmD) curriculum. Methods. A survey was conducted to determine preceptors' perceptions of the value of a required pharmacy student research project and dissemination of research results. Results. One hundred fifteen project preceptors (92.0%) responded. Most preceptors agreed that the projects provided a valuable learning experience to the students (87.5%) and were of value to them professionally (82.1%) and to their institution (78.2%). Study findings were disseminated primarily through institutional forums (47.3%). A smaller percentage of projects were disseminated externally through presentations at professional meetings (23.7%, poster presentations; 4.0%, platform presentations), and peer-reviewed publications (5.3%). Conclusions. Despite a modest level of dissemination of project results through presentations at professional meetings and a low level of dissemination via published manuscripts, the majority of preceptors perceived a required student research project to be of value
Recursion representation of the Neveu-Schwarz superconformal block
Four-point super-conformal blocks for the N = 1 Neveu-Schwarz algebra are
defined in terms of power series of the even super-projective invariant.
Coefficients of these expansions are represented both as sums over poles in the
"intermediate" conformal weight and as sums over poles in the central charge of
the algebra. The residua of these poles are calculated in both cases. Closed
recurrence relations for the block coefficients are derived.Comment: 20 page
Knowledge Questions from Knowledge Graphs
We address the novel problem of automatically generating quiz-style knowledge questions from a knowledge graph such as DBpedia. Questions of this kind have ample applications, for instance, to educate users about or to evaluate their knowledge in a specific domain. To solve the problem, we propose an end-to-end approach. The approach first selects a named entity from the knowledge graph as an answer. It then generates a structured triple-pattern query, which yields the answer as its sole result. If a multiple-choice question is desired, the approach selects alternative answer options. Finally, our approach uses a template-based method to verbalize the structured query and yield a natural language question. A key challenge is estimating how difficult the generated question is to human users. To do this, we make use of historical data from the Jeopardy! quiz show and a semantically annotated Web-scale document collection, engineer suitable features, and train a logistic regression classifier to predict question difficulty. Experiments demonstrate the viability of our overall approach
Limits of minimal models and continuous orbifolds
The lambda=0 't Hooft limit of the 2d W_N minimal models is shown to be
equivalent to the singlet sector of a free boson theory, thus paralleling
exactly the structure of the free theory in the Klebanov-Polyakov proposal. In
2d, the singlet sector does not describe a consistent theory by itself since
the corresponding partition function is not modular invariant. However, it can
be interpreted as the untwisted sector of a continuous orbifold, and this point
of view suggests that it can be made consistent by adding in the appropriate
twisted sectors. We show that these twisted sectors account for the `light
states' that were not included in the original 't Hooft limit. We also show
that, for the Virasoro minimal models (N=2), the twisted sector of our orbifold
agrees precisely with the limit theory of Runkel & Watts. In particular, this
implies that our construction satisfies crossing symmetry.Comment: 33 pages; v2: minor improvements and references added, published
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Hot-cracking of high-alloyed steels evaluated by wedge rolling test
We present a new methodology of determination of hot-cracking f metallic materials, which is based on laboratory application of the wedge rolling test and computer processing of the results obtained. The experiment was made with selected new types of high-alloyed free-cutting (ferritic and austenitic) steels. The initial specimens underwent an additional modification enabling easier development of cracks which consisted in milling out of the defined V-shaped notches on a side wall of a specimen. After taking specimens from the rolled material, we performed the metallographic analysis of microstructures by means of optical microscopy as well as a SEM analysis of the cracks. The resulting microstructure in the propagating crack vicinity was markedly influenced by this fracture. In the crack vicinity, a noticeable refinement of grains was observed due to the stress-induced recrystallization and occurrence of deformation zones that were pronounced by the rolled-out and stretched sulphides. As a rule, fractures were created by the ductile failure with visible pits, caused by tearing of sulphides from the material. Susceptibility of the studied steels to hot-cracking was evaluated and compared.Представлен новый метод определения горячих трещин в металлических материалах, основанный на лабораторной методике прокатки на клин и компьютерной обработке результатов. Эксперименты выполняли на отобранных высоколегированных автоматных (ферритных и аустенитных) сталях нового типа. В исходных образцах фрезеровали У-образные надрезы на их боковой стороне, что облегчало развитие трещин. После вырезки образцов из прокатанного материала выполняли металлографический анализ микроструктуры с помощью оптической микроскопии и анализ трещин с помощью сканирующей микроскопии. Разрушение в значительной мере влияло на микроструктуру, возникшую вблизи развивающейся трещины. Вблизи трещины наблюдалось заметное изменение зерен вследствие рекристаллизации, вызванной напряжениями, и появления зон деформирования, соответствующих прокатанным и вытянутым сульфидам. Как правило, разрушение возникало за счет пластического разрыва с видимыми ямками, вызванного отрывом сульфидов от материала. Оценивалась и сравнивалась склонность изучаемых сталей к образованию горячих трещин
On "Dotsenko-Fateev" representation of the toric conformal blocks
We demonstrate that the recent ansatz of arXiv:1009.5553, inspired by the
original remark due to R.Dijkgraaf and C.Vafa, reproduces the toric conformal
blocks in the same sense that the spherical blocks are given by the integral
representation of arXiv:1001.0563 with a peculiar choice of open integration
contours for screening insertions. In other words, we provide some evidence
that the toric conformal blocks are reproduced by appropriate beta-ensembles
not only in the large-N limit, but also at finite N. The check is explicitly
performed at the first two levels for the 1-point toric functions.
Generalizations to higher genera are briefly discussed.Comment: 10 page
Effects of differentiation on purinergic and neurotensin-mediated calcium signaling in human HT-29 colon cancer cells
Calcium signaling is a key regulator of processes important in differentiation. In colon cancer cells differentiation is associated with altered expression of specific isoforms of calcium pumps of the endoplasmic reticulum and the plasma membrane, suggesting that differentiation of colon cancer cells is associated with a major remodeling of calcium homeostasis. Purinergic and neurotensin receptor activation are known regulators of cytosolic free Ca2+ levels in colon cancer cells. This study aimed to assess changes in cytosolic free Ca2+ levels in response to ATP and neurotensin with differentiation induced by sodium butyrate or culturing post-confluence. Parameters assessed included peak cytosolic free Ca2+ level after activation; time to reach peak cytosolic free Ca2+ and the EC50 of dose response curves. Our results demonstrate that differentiation of HT-29 colon cancer cells is associated with a remodeling of both ATP and neurotensin mediated Ca2+ signaling. Neurotensin-mediated calcium signaling appeared more sensitive to differentiation than ATP-mediated Ca2+ signaling. (c) 2013 Elsevier Inc. All rights reserved
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