83 research outputs found
Experimental quantification of entanglement through heat capacity
No full textA new experimental realization of heat capacity as an entanglement witness is reported. Entanglement properties of a low-dimensional quantum spin system are investigated by heat capacity measurements performed down to very low temperatures (400 mK), for various applied magnetic field values. The experimentally extracted results for the value of heat capacity at zero field matches perfectly with the theoretical estimates of entanglement from model Hamiltonians. The studied sample is a spin half antiferromagnetic system that shows a clear signature of quantum phase transition at very low temperatures when the heat capacity is varied as a function of fields at a fixed temperature. The variation of entanglement as a function of field is then explored in the vicinity of the quantum phase transition to capture the sudden loss of entanglement.Open-Access-Publikationsfonds 201
O uso de repetição em processos criativos e suas transformações em cena
No full textO presente trabalho relata e analisa o uso da repetição em processos criativos experenciados pelo autor durante sua graduação em Interpretação Teatral na Universidade Federal do Rio Grande do sul (UFRGS). O principal objeto de pesquisa é a noção repetição utilizada na constituição do espetáculo Alhures - estágio de atuação do autor –, como ela é aplicada e como transforma as cenas apresentadas. O trabalho também analisa experimentos de criação derivados do espetáculo em questão, como partituras, textos e desenhos. Passando por referências como Pina Bausch, Ciane Fernandes, Fayga Ostrower, Maria Lídia Magliani, Jacques Lecoq e Yoshi Oida, o autor explora diferentes campos das artes buscando e pesquisando a repetição, suas diferentes formas de variação.The present work reports and analyzes the use of repetition in creative processes experienced by the author during his graduation in Theater Interpretation at the Federal University of Rio Grande do Sul (UFRGS). The main object of research is the notion of repetition used in the constitution of the show Alhures – acting internship of the author -, how it is applied and how it transforms the scenes presented. The work also analyzes creative experiments derivative from the show in question, such as scores, texts and drawings. Going through references such as Pina Bausch, Ciane Fernandes, Fayga Ostrower, Maria Lídia Magliani, Jacques Lecoq and Yoshi Oida, the author explores different fields of the arts seeking and researching repetition, its different forms of variation
Atmospheric response to interannual variability of sea surface temperature front in the East China Sea in early summer
No full textThe atmospheric response, especially the response of the meiyu-baiu rainband, to interannual variability of the sea surface temperature (SST) front associated with the Kuroshio in the East China Sea in early summer is examined by using reanalysis, satellite, and rain-gauge datasets from 1982 to 2010. It is revealed that the strong (weak) SST front in the East China Sea is accompanied by the heavy (weak) precipitation over the central East China Sea and the southern Japan. Because the strong SST front largely results from the negative SST anomaly over the continental shelf, the local evaporation change in the East China Sea is not balanced by this enhanced precipitation. The moisture for this enhanced precipitation is supplied by interannual variability of horizontal wind convergence over the central East China Sea. In addition to the precipitation change, the strong SST front is also accompanied by the intensification of weather disturbances in the lower troposphere over the East China Sea. This is probably because the negative SST anomaly over the continental shelf enhances the baroclinicity in the lower troposphere. This intensification of the weather disturbances over the East China Sea can explain the enhanced precipitation over the central East China Sea in response to the interannual variability of the SST front. Because the SST anomaly over the continental shelf, which primarily determines the interannual variability of the SST front, persists for a couple of months, these results imply the predictability of the precipitation associated with the meiyu-baiu rainband
Datasets produced by SCALE-GM in QBO-like oscillation experiments.
No full textData produced by SCALE-GM and used in the manuscript submitted to the AMS journal Monthly Weather Review.
Authors:
Hiroki Kashimura, Hisashi Yashiro, Seiya Nishizawa, Hirofumi Tomita, Kensuke Nakajima, Masaki Ishiwatari, Yoshiyuki O. Takahashi, and Yoshi-Yuki Hayashi
Corresponding Author:
Hiroki Kashimura ([email protected])
Manuscript Title:
Dependence of a QBO-like oscillation on time-step intervals in a non-hydrostatic general circulation model
See README.txt for more details
Avaliação das comunidades de formigas em uma área de extração madeireira
No full textThis work presents a comparative study of ant fauna communities inhabiting in a primary tropical forest and two types of logging systems (Managed and Traditional) located in Paragominas, PA, Brazil. From each area, ants were sampled using pitfall traps (Majer & Delabie 1994) in six 200m transects separated from each other by 100m. Differences in ant fauna diversity in the three forest types were tested using índices of diversity (Shannon, Simpson and Fisher's Alpha) and richness estimates protocols (Colwell Coddington 1994). Species composition was evaluated through affinity analysis (Scheiner 1992) and indices of similarity (jaccard and Morisita-Horn). A total of 134 ant species belonging to seven subfamilies and 42 genera were identified in the entire area. From these, 90 species were found in Primary Forest, 90 in Managed logged forest and 84 in the Traditional logged Forest. Differences between habitats could be detected by comparing diversity and similarity indices in different transects/habitats. There were no differences in índices when absolute values were compared for each habitat. Results from richness estimate protocols indicate that ant fauna was similar between habitats and suggests that ant fauna diversity was underestimated. Periodic variations on pluviosity had a strong effect on diversity and richness estimates in the three forest types. The ant fauna composition was similar between habitats; however, a high mosaic diversity could be detected by using affinity analysis, suggesting that the ant community is composed of complex gradients. Thus differences in ant composition would be detectable at smaller scales.WWF - World Wildlife FundCNPq - Conselho Nacional de Desenvolvimento Científico e TecnológicoEste trabalho apresenta um estudo comparativo entre as comunidades de formigas, existentes em uma floresta primária e dois tipos de sistemas de extração de madeira (Manejado e Tradicional) em uma área Tropical localizada em Paragominas, PA. Formigas foram amostradas através de pitfall-traps (Majer & Delabie 1994) em transetos de 200m separados 100m entre si. Diferenças na diversidade da fauna de formigas entre estes hábitats foram testadas por meio de Índices de Diversidade (Shannon, Simpson and Fisher's Alpha), e Protocolos de Estimativa de Riqueza (Colwell & Coddington 1994). A composição de espécies foi avaliada empregando Análises de Afinidade (Scheiner 1992) e índices de Similaridade (Jaccard and Morisita-florn). No total, 134 espécies de formigas, pertencentes a sete subfamílias e 42 gêneros foram identificadas em na área toda. Destas, 90 foram encontradas na Floresta Primária, 90 no Corte Manejado e 84 no Sistema de Corte Tradicional. Diferenças entre na Diversidade e Similaridade entre hábitats apenas puderam ser detectadas quando comparados transectos/hábitats. Quando os índices foram comparados através dos valores absolutos calculados para cada hábitat, a diferença desaparece. Os resultados dos Protocolos de Estimativa de Riqueza empregados indicam que a fauna de formigas foi igual entre os hábitats e sugerem que a fauna está subestimada. Variações periódicas na temperatura e umidade podem ter um forte efeito, igualmente nas estimativas de Diversidade e de Riqueza nos hábitats estudados. Análises na composição mostram que a fauna de formigas é similar entre os hábitats, e apesar desta similaridade, pudemos detectar através da Análise de Afinidade uma alta Diversidade de Mosaico, a qual sugere que a comunidade é composta por gradientes muito complexos, assim diferenças na composição poderão estar ocorrendo em escalas menores
Creating New Train Timetables in Case of Disruptions: Optimising a Branch & Bound Algorithm
No full textThe Dutch railway system is one of the most densely used systems worldwide and the busiest in Europe. Given the tight schedules, incidents can quickly cascade through the entire country if not handled properly. Alternative timetables are created to help train traffic controllers swiftly resolve such incidents. These schedules are currently created manually, but the team cannot keep up with demand. This is why CGI is developing VGB Solver, an application to automatically generate such timetables. The solver uses a branch and bound algorithm in which nodes are processed in best-first order, based on a heuristic value. For this thesis, different performance optimisations for this algorithm were implemented and analysed.Various alternative formulations of the heuristic value, used to determine the likeliness of a node leading to a good solution, showed promising results.One of these formulas resulted in solutions for 96% more scenarios than before, and improved the quality of solutions for other scenarios.Using machine learning, a decision tree was created to predict whether applying another new formula for the heuristic value gives better results than the old formula. This classifier achieved an accuracy of 73.5% on the test data. Having the solver choose between the old and new formula based on that classification resulted in some scenarios with worse scores, but twice as many improved, and the average improvement was higher than the average deterioration.Recommendations are made to conduct further experiments related to the heuristic value calculation. Furthermore, it is suggested to separate the scores for evaluating solution quality from the heuristic value formula, to facilitate more fine-grained changes to the calculation of the heuristic value.Computer Scienc
Esforço amostral e ecologia de formigas de liteira, com ênfase em Gnamptogenys e Pachycondyla (Hymenoptera: Formicidae) em uma floresta de terra firme na Amazônia Oriental
No full textThe increasing use of ants (Hymenoptera: Formicidae) for monitoring and in inventory programs results in a greater amount of sampling material, with financial limitations and lack of experts to make the taxonomy of this group. I looked forward to overcoming these problems through the analysis of the effort of the TEAM Project protocol, using the concepts of taxonomic sufficiency, rarefaction and sample dilution, applied to the randomization test of Mantel, to verify the autocorrelation among groups of samples. The ants were identified to genus and the individuals of Pachycondyla and Gnamptogenys to species. The aim of the study was to determine the minimum effort necessary to obtain an appropriate inventory of these taxa, evaluating the minimum number of samples and the maximum dilution to detect them without reducing the viability of the data, and also, to determine the effect of the environmental variables over the taxocenoses. In a continuous primary forest area, during October 26th and November 3rd, 2003, during the dry season, I sampled ants and other invertebrates in 6 plots distributed in 33,000 ha. Each plot was 1 km2 and in each one, 4 transects of 100 m were surveyed. Using Winkler and pitfall traps 10 sub-samples were collected in each transect, separated 10 m from each other. The environmental variables (volume of litter, percentage of sand, temperature and pH of the soil) utilized were not enough to explain the distribution of the species studied. Apparently the number of species in a group of samples is not the only determinant condition to proceed in the dilution of the samples. It is desirable that the analyses proceeded in this study can be repeated with a greater number of samples of this same protocol. Protocols oriented to a group that encompasses a larger number of species can have amostral mistakes because of the distinct ecological requirements of the species involved. Isolated ecological studies encompassing Gnamptogenys and Pachycondyla are necessary to establish those factors that are related to the distribution of these species.A ampliação do uso das formigas (Hymenoptera: Formicidae) em monitoramentos e inventários implica em uma crescente quantidade de material coletado, limitação financeira e de pessoal treinado na taxonomia deste grupo. Busquei contornar estas limitações, através da análise do esforço do protocolo do Projeto TEAM, utilizando os conceitos de suficiência e resolução taxonômica, rarefação e diluição de amostras, aliados ao teste de randomização de Mantel para verificar a autocorrelação entre os conjuntos de amostras. As formigas foram identificadas a gênero e os indivíduos dos gêneros Pachycondyla e Gnamptogenys, a espécie. Objetivei determinar qual o esforço mínimo exigido para obter um inventário adequado destes taxa, avaliando qual o número mínimo de amostras e a diluição máxima das mesmas para detectá-los sem reduzir a viabilidade dos dados, e ainda, determinar o efeito das variáveis ambientais, sobre as taxocenoses. Coletei nas parcelas do TEAM-Caxiuanã, localizadas na Estação Científica Ferreira Penna, com o método Winkler e Pitfall, de 26/10 à 3/11/03, durante a estação seca. A unidade amostral empregada foi o transecto de 100 m, num total de 24 com 10 sub-amostras distando 10 metros entre si. As variáveis ambientais empregadas não foram suficientes para explicar a distribuição das espécies estudadas. Aparentemente o número de espécies em um conjunto de amostras não é condição determinante para diluir as amostras, mas sim a abundância. É desejável que as análises feitas neste estudo sejam replicadas com uma maior número de coletas deste mesmo protocolo. Protocolos orientados para um grupo que engloba um grande número de espécies podem incorrer em erros amostrais devido aos distintos requerimentos ecológicos das espécies envolvidas. Estudos ecológicos tratando em isolado as espécies de Gnamptogenys e Pachycondyla, são necessários para se estabelecer quais fatores condicionam a distribuição destas
DIMENSIONALITY REDUCTION TECHNIQUES FOR SEARCH RESULTS CLUSTERING by STANISŁAW OSIŃSKI Supervisor
No full textAll sentences or passages quoted in this dissertation from other people's work have been specifically acknowledged by clear cross-referencing to author, work and page(s). Any illustrations which are not the work of the author of this dissertation have been used with the explicit permission of the originator and are specifically acknowledged. I understand that failure to do this amounts to plagiarism and will be considered grounds for failure in this dissertation and the degree examination as a whole
Climatological mean features and interannual to decadal variability of ring formations in the Kuroshio Extension region
No full textThis study examines the climatological mean features of oceanic rings shed from the Kuroshio Extension (KE) jet and their interannual to decadal variability using satellite altimeter observations from October 1992 to December 2010. To objectively capture ring shedding from the KE jet, a new method that consists of the detection of the jet length changes and the tracking of a ring is proposed. Spatial distribution of the ring formations in the KE region indicates that cyclonic (cold-core) rings were most frequently formed in the upstream region between 143A degrees and 147A degrees E around the steady meander of the KE jet. In contrast, most of anticyclonic (warm-core) rings were formed in the downstream region west of the Shatsky Rise. These pinched-off rings in both the upstream and downstream regions generally propagated westward, but about two-thirds of the rings were reabsorbed by the jet. Nevertheless, about one-fourth of the meridional eddy heat transport at the latitude of the KE resulted from the rings that are not reabsorbed by the jet. The number of ring formations showed substantial interannual to decadal variability. In the upstream and downstream KE region, decadal and interannual variability was dominant, respectively. These ring formation fluctuations were negatively correlated with the strength of the KE jet. It is also revealed that the ring formation variations play an important role in sea surface temperature changes north of the KE jet
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