8,834 research outputs found
Tripartite Graph Clustering for Dynamic Sentiment Analysis on Social Media
The growing popularity of social media (e.g, Twitter) allows users to easily
share information with each other and influence others by expressing their own
sentiments on various subjects. In this work, we propose an unsupervised
\emph{tri-clustering} framework, which analyzes both user-level and tweet-level
sentiments through co-clustering of a tripartite graph. A compelling feature of
the proposed framework is that the quality of sentiment clustering of tweets,
users, and features can be mutually improved by joint clustering. We further
investigate the evolution of user-level sentiments and latent feature vectors
in an online framework and devise an efficient online algorithm to sequentially
update the clustering of tweets, users and features with newly arrived data.
The online framework not only provides better quality of both dynamic
user-level and tweet-level sentiment analysis, but also improves the
computational and storage efficiency. We verified the effectiveness and
efficiency of the proposed approaches on the November 2012 California ballot
Twitter data.Comment: A short version is in Proceeding of the 2014 ACM SIGMOD International
Conference on Management of dat
Coupled Microwave Billiards as a Model for Symmetry Breaking
Two superconducting microwave billiards have been electromagnetically coupled
in a variable way. The spectrum of the entire system has been measured and the
spectral statistics analyzed as a function of the coupling strength. It is
shown that the results can be understood in terms of a random matrix model of
quantum mechanical symmetry breaking -- as e.g. the violation of parity or
isospin in nuclear physics.Comment: 4 pages, 5 figure
Coleção Biológica de trabalho de Fitonematoides da Embrapa Mandioca e Fruticultura.
O Brasil é um dos três maiores produtores de frutas do mundo, com destaque para as culturas da bananeira, citros, mamoeiro, abacaxi, maracujá, entre outras.bitstream/item/77660/1/Folder-Colecao-Biologica-de-Fitonematoide-2012.pd
Fast and secure key distribution using mesoscopic coherent states of light
This work shows how two parties A and B can securely share sequences of
random bits at optical speeds. A and B possess true-random physical sources and
exchange random bits by using a random sequence received to cipher the
following one to be sent. A starting shared secret key is used and the method
can be described as an unlimited one-time-pad extender. It is demonstrated that
the minimum probability of error in signal determination by the eavesdropper
can be set arbitrarily close to the pure guessing level. Being based on the
-ry encryption protocol this method also allows for optical amplification
without security degradation, offering practical advantages over the BB84
protocol for key distribution.Comment: 11 pages and 4 figures. This version updates the one published in PRA
68, 052307 (2003). Minor changes were made in the text and one section on
Mutual Information was adde
Confronting cold dark matter cosmologies with strong clustering of Lyman break galaxies at
We perform a detailed analysis of the statistical significance of a
concentration of Lyman break galaxies at recently discovered by
Steidel et al. (1997), using a series of N-body simulations with
particles in a (100\himpc)^3 comoving box. While the observed number density
of Lyman break galaxies at implies that they correspond to systems
with dark matter halos of \simlt 10^{12}M_\odot, the resulting clustering of
such objects on average is not strong enough to be reconciled with the
concentration if it is fairly common; we predict one similar concentration
approximately per () fields in three representative cold dark matter
models. Considering the current observational uncertainty of the frequency of
such clustering at , it would be premature to rule out the models, but
the future spectroscopic surveys in a dozen fields could definitely challenge
all the existing cosmological models a posteriori fitted to the universe.Comment: the final version which matchs that published in ApJ Letters (Feb
1998); compared with the previous versions, the predictions for the SCDM
model are slightly changed; Latex, 11 pages, including 3 ps figure
Strings, T-duality breaking, and nonlocality without the shortest distance
T-duality of string theory suggests nonlocality manifested as the shortest
possible distance. As an alternative, we suggest a nonlocal formulation of
string theory that breaks T-duality at the fundamental level and does not
require the shortest possible distance. Instead, the string has an objective
shape in spacetime at all length scales, but different parts of the string
interact in a nonlocal Bohmian manner.Comment: 7 pages, revised, to appear in Eur. Phys. J.
The Effect of Radiative Cooling on the Sunyaev-Zel'dovich Cluster Counts and Angular Power Spectrum: Analytic Treatment
Recently, the entropy excess detected in the central cores of groups and
clusters has been successfully interpreted as being due to radiative cooling of
the hot intragroup/intracluster gas. In such a scenario, the entropy floors
in groups/clusters at any given redshift are completely
determined by the conservation of energy. In combination with the equation of
hydrostatic equilibrium and the universal density profile for dark matter, this
allows us to derive the remaining gas distribution of groups and clusters after
the cooled material is removed. Together with the Press-Schechter mass function
we are able to evaluate effectively how radiative cooling can modify the
predictions of SZ cluster counts and power spectrum. It appears that our
analytic results are in good agreement with those found by hydrodynamical
simulations. Namely, cooling leads to a moderate decrease of the predicted SZ
cluster counts and power spectrum as compared with standard scenario. However,
without taking into account energy feedback from star formation which may
greatly suppress cooling efficiency, it is still premature to claim that this
modification is significant for the cosmological applications of cluster SZ
effect.Comment: 16 pages, 3 figures, uses aastex.cls. ApJ accepte
Avaliação da dinâmica da água no solo e da evapotranspiração, trocas gasosas, estado hídrico e produção da videira.
NO VALE DO SUBMÉDIO SÃO FRANCISCO, OS CULTIVOS DE VIDEIRA DE VINHO SÃO IRRIGADOS DURANTE TODO O ANO. NESSE CULTIVO, A IRRIGAÇÃO COM DEFICIT É UTILIZADA PARA OBTER ALGUMAS CARACTERÍSTICAS DESEJÁVEIS NA UVA PARA A VINIFICAÇÃO. ASSIM, O OBJETIVO DESSE TRABALHO FOI AVALIAR OS EFEITOS DE ESTRATÉGIAS DE IRRIGAÇÃO COM DÉFICIT NA PRODUÇÃO DE UVAS DE VINHO EM PETROLINA - PE. O EXPERIMENTO FOI INSTALADO NA EMBRAPA SEMIÁRIDO. A VIDEIRA CV. SYRAH ENXERTADA SOBRE PAULSEN 1103 FOI PLANTADA EM 30 DE ABRIL DE 2009, NO ESPAÇAMENTO DE 1 M X 3 M, E IRRIGADA POR GOTEJAMENTO EM UM ARGISSOLO VERMELHO AMARELO EUTRÓFICO LATOSSÓLICO, TEXTURA MÉDIA. OS TRATAMENTOS DE MANEJO DE IRRIGAÇÃO FORAM: 1 - IRRIGAÇÃO PLENA (IP), SEM A RESTRIÇÃO DE ÁGUA ÀS VIDEIRAS DURANTE TODO O CICLO DE PRODUÇÃO; 2 - IRRIGAÇÃO COM DÉFICIT (ID), ONDE A APLICAÇÃO DE ÁGUA FOI INTERROMPIDA DESDE A FASE DE CACHO FECHADO ATÉ A COLHEITA; 3 - A IRRIGAÇÃO COM DEFICIT CONTROLADO (IDC), ONDE A APLICAÇÃO DE ÁGUA FOI INTERROMPIDA NA FASE DE CACHO FECHADO, COM IRRIGAÇÕES EVENTUAIS CONFORME O MONITORAMENTO DA UMIDADE DO SOLO. NO SÉTIMO CICLO DE PRODUÇÃO (7 DE MAIO DE 2014 A 3 DE SETEMBRO DE 2014 - 119 DIAS), OCORREU UMA PRECIPITAÇÃO TOTAL DE 15,5 MM, SENDO 10,7 MM APÓS A INTERRUPÇÃO DA IRRIGAÇÃO. OS VALORES MÉDIOS DE EVAPOTRANSPÍRAÇÃO DE REFERÊNCIA (ETO) E EVAPOTRANSPIRAÇÃO DA CULTURA (ETC) PARA O PERÍODO DE 119 DIAS FORAM DE 5,0 MM DIA-1 E 3,6 MM DIA-1, RESPECTIVAMENTE, ENQUANTO OS MAIORES VALORES FORAM DE 9,3 MM DIA-1 (115 DIAS APÓS A PODA DE PRODUÇÃO - DAPP, 30 DE AGOSTO DE 2014) E 7,4 MM DIA-1 (80 DAPP, 26 DE JULHO DE 2014). A LÂMINA BRUTA MÉDIA FOI DE 5,6 MM DIA-1 NO TRATAMENTO IP, PARA 83 DIAS DE IRRIGAÇÃO; 5,9 MM DIA-1 NO TRATAMENTO IDC, PARA 42 DIAS DE IRRIGAÇÃO, E 6,1 MM DIA-1 NO TRATAMENTO ID, EM 37 DIAS DE IRRIGAÇÃO. APÓS O INÍCIO DA INTERRUPÇÃO DA IRRIGAÇÃO NOS TRATAMENTOS ID E IDC, A REDUÇÃO DA UMIDADE DO SOLO OCORREU ATÉ A PROFUNDIDADES DE 0,6 M, EM DECORRÊNCIA DA MAIOR PRESENÇA DO SISTEMA RADICULAR DA CULTURA NESSA CAMADA DE SOLO. NAS PROFUNDIDADES DE 0,75 M A 1,0 M, AS VARIAÇÕES NOS VALORES DE UMIDADE FORAM MENORES. OS VALORES DE POTENCIAL HÍDRICO NA ANTEMANHÃ E AO MEIO-DIA. APRESENTARAM COMPORTAMENTO SIMILAR, COM MAIORES VALORES NAS PLANTAS DE IP E MENORES NAS PLANTAS DE IDC E ID. ENTRETANTO, AS PLANTAS EM IDC E ID NÃO APRESENTAVAM SINTOMAS DE PONTO DE MURCHA PERMANENTE DURANTE A AVALIAÇÃO DE ANTEMANHÃ. OS MENORES VALORES DE POTENCIAL HÍDRICO AO MEIO-DIA EM PLANTAS DE TODOS OS TRATAMENTOS ESTÃO RELACIONADOS COM OS VALORES DA TAXA DE TRANSPIRAÇÃO, OS QUAIS TENDEM A SEREM MAIORES NESTE HORÁRIO, UMA VEZ QUE AS PLANTAS ESTAVAM PERDENDO ÁGUA PARA A ATMOSFERA VIA TRANSPIRAÇÃO. HOUVE EFEITO DOS TRATAMENTOS NA MASSA TOTAL DE CACHOS, NÚMERO DE CACHOS POR PLANTA, MASSA DE CACHOS POR PLANTA E NA PRODUTIVIDADE, COM MAIORES VALORES NO TRATAMENTO IP, SEM DIFERENÇA ESTATÍSTICA PARA O TRATAMENTO IDC. QUANTO A MASSA MÉDIA DE CACHOS, O TRATAMENTO IP APRESENTOU MAIORES VALORES
Water-like hierarchy of anomalies in a continuous spherical shouldered potential
We investigate by molecular dynamics simulations a continuous isotropic
core-softened potential with attractive well in three dimensions, introduced by
Franzese [cond-mat/0703681, to appear on Journal of Molecular Liquids], that
displays liquid-liquid coexistence with a critical point and water-like density
anomaly. Here we find diffusion and structural anomalies. These anomalies occur
with the same hierarchy that characterizes water. Yet our analysis shows
differences with respect to the water case. Therefore, many of the anomalous
features of water could be present in isotropic systems with soft-core
attractive potentials, such as colloids or liquid metals, consistent with
recent experiments showing polyamorphism in metallic glasses.Comment: 27 pages, 9 figures. to appear in J. Chem. Phy
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