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## Preservação digital:análise dos periódicos da base BRAPCI.

Fonte: Universidade Federal de Santa Catarina
Publicador: Universidade Federal de Santa Catarina

Tipo: Relatório

Português

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A preservação digital garante a duração dos objetos digitais por um longo período de tempo, sua aplicação deve ser criteriosa e baseada em estratégias confiáveis. O
trabalho faz uma reflexão sobre as estratégias de preservação digital que podem ser aplicadas nos periódicos científicos digitais. Foram analisados individualmente os
periódicos da área de Ciência da Informação indexados na Base de Dados da BRAPCI, bem como as tecnologias de preservação digital utilizadas, a fim de
levantar as estratégias de preservação existentes. Com base na fundamentação teórica de preservação digital foram identificadas as estratégias existentes com o
intuito de compará-las com as que são utilizadas nos periódicos selecionados. Essas tecnologias têm funções distintas, o PDF/A pode ser usado como formato padrão de
preservação; o uso do DOI ajuda na recuperação dos objetos digitais; o LOCKSS garante a manutenção dos documentos eletrônicos.

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## Acrobat Pro 9

Fonte: Universidade Federal de Santa Catarina
Publicador: Universidade Federal de Santa Catarina

Tipo: Software

Português

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Software que permite a criação e edição de arquivos PDF.

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## Pdf´s interactivos

Fonte: Universidade Nova de Lisboa
Publicador: Universidade Nova de Lisboa

Tipo: Outros

Publicado em 29/01/2009
Português

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Este guião de apoio à formação tem como objectivo apoiar docentes na (1) utilização de funcionalidades avançadas do Adobe Acrobat Professional e (2) produção de documentos interactivos com fins educativos.

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## Desktop document delivery using portable document format (PDF) files and the Web.

Fonte: PubMed
Publicador: PubMed

Tipo: Artigo de Revista Científica

Publicado em /07/1998
Português

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Desktop access to electronic full-text literature was rated one of the most desirable services in a client survey conducted by the University of Washington Libraries. The University of Washington Health Sciences Libraries (UW HSL) conducted a ten-month pilot test from August 1996 to May 1997 to determine the feasibility of delivering electronic journal articles via the Internet to remote faculty. Articles were scanned into Adobe Acrobat Portable Document Format (PDF) files and delivered to individuals using Multipurpose Internet Mail Extensions (MIME) standard e-mail attachments and the Web. Participants retrieved scanned articles and used the Adobe Acrobat Reader software to view and print files. The pilot test required a special programming effort to automate the client notification and file deletion processes. Test participants were satisfied with the pilot test despite some technical difficulties. Desktop delivery is now offered as a routine delivery method from the UW HSL.

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## Crystallization and preliminary X-ray crystallographic analysis of peptide deformylase (PDF) from Bacillus cereus in ligand-free and actinonin-bound forms

Fonte: International Union of Crystallography
Publicador: International Union of Crystallography

Tipo: Artigo de Revista Científica

Publicado em 24/12/2004
Português

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Peptide deformylase (PDF) from B. cereus has been overexpressed, purified and crystallized in ligand-free and actinonin-bound forms. Diffraction data have been collected from these crystals to 1.7 and 2.0 Å resolution, respectively.

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## Enhanced Techniques for PDF Image Segmentation and Text Extraction

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 01/10/2012
Português

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Extracting text objects from the PDF images is a challenging problem. The
text data present in the PDF images contain certain useful information for
automatic annotation, indexing etc. However variations of the text due to
differences in text style, font, size, orientation, alignment as well as
complex structure make the problem of automatic text extraction extremely
difficult and challenging job. This paper presents two techniques under
block-based classification. After a brief introduction of the classification
methods, two methods were enhanced and results were evaluated. The performance
metrics for segmentation and time consumption are tested for both the models.; Comment: 5 pages, 5 figures

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## PDF Fits at HERA

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 09/12/2011
Português

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The HERAPDF1.0 PDF set, which was an NLO QCD analysis based on H1 and ZEUS
combined inclusive cross section data from HERA-I, has been updated to
HERAPDF1.5 by including preliminary inclusive cross section data from HERA-II
running. Studies have also been made by adding various other HERA data sets:
combined charm data, combined low energy run data and H1 and ZEUS jet data.
These data give information on the treatment of charm and the charm quark mass
and on the value of $\alpha_s(M_Z)$. The PDF analysis has also been extended to
NNLO. The PDFs give a good description of Tevatron and early LHC data.; Comment: On behalf of ZEUS and H1 collaborations, 6 pages, 6 figures. To
appear in the Proceedings of the 2011 Europhysics Conference on High Energy
Physics, HEP 2011, July 2011, Grenoble, France

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## Hessian PDF reweighting meets the Bayesian methods

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 20/08/2014
Português

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We discuss the Hessian PDF reweighting - a technique intended to estimate the
effects that new measurements have on a set of PDFs. The method stems
straightforwardly from considering new data in a usual $\chi^2$-fit and it
naturally incorporates also non-zero values for the tolerance,
$\Delta\chi^2>1$. In comparison to the contemporary Bayesian reweighting
techniques, there is no need to generate large ensembles of PDF Monte-Carlo
replicas, and the observables need to be evaluated only with the central and
the error sets of the original PDFs. In spite of the apparently rather
different methodologies, we find that the Hessian and the Bayesian techniques
are actually equivalent if the $\Delta\chi^2$ criterion is properly included to
the Bayesian likelihood function that is a simple exponential.; Comment: Transcription of the talk given in DIS2014 conference

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## Lagrangian Investigation of Auto-ignition in a Hydrogen Jet Flame in a Vitiated Co-flow: Animations of Particle Trajectories in Composition Space from PDF Model Calculations

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 07/09/2007
Português

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PDF model calculations have been performed of the Cabra lifted hydrogen flame
in a vitiated co-flow. Particle trajectories are extracted from the Lagrangian
particle method used to solve the modeled PDF equation. The particle
trajectories in the mixture fraction-temperature plane reveal (at successive
downstream locations): essentially inert mixing between the cold fuel jet and
the hot co-flow; the auto-ignition of very lean particles; and, subsequent
mixing and reaction, leading to near-equilibrium compositions. The purpose of
this paper is to present animations of the particle trajectories obtained using
different turbulent mixing models.; Comment: 5 pages, 3 figures. Video 1 (EMST)
http://ecommons.library.cornell.edu/bitstream/1813/8237/2/LIFTED_H2_EMST_FUEL.mpg
Video 2 (IEM)
http://ecommons.library.cornell.edu/bitstream/1813/8237/4/LIFTED_H2_IEM_FUEL.mpg

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## Measuring the History of Cosmic Reionization using the 21-cm Difference PDF

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 25/09/2012
Português

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During cosmic reionization, the 21-cm brightness fluctuations were highly
non-Gaussian, and complementary statistics can be extracted from the
distribution of pixel brightness temperatures that are not derivable from the
21-cm power spectrum. One such statistic is the 21-cm difference PDF, the
probability distribution function of the difference in the 21-cm brightness
temperatures between two points, as a function of the distance between the
points. Guided by 21-cm difference PDFs extracted from simulations, we perform
a maximum likelihood analysis on mock observational data, and analyze the
ability of present and future low-frequency radio array experiments to estimate
the shape of the 21-cm difference PDF, and measure the history of cosmic
reionization. We find that one-year data with an experiment such as the
Murchison Wide-field Array should suffice for probing large scales during the
mid-to-late stages of reionization, while a second-generation experiment should
yield detailed measurements over a wide range of scales during most of the
reionization era.; Comment: 11 pages, 17 figures. Submitted to MNRAS

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## Theoretical issues in PDF determination and associated uncertainties

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Português

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We study several sources of theoretical uncertainty in the determination of
parton distributions (PDFs) which may affect current PDF sets used for
precision physics at the Large Hadron Collider, and explain discrepancies
between them. We consider in particular the use of fixed-flavor versus
variable-flavor number renormalization schemes, higher twist corrections, and
nuclear corrections. We perform our study in the framework of the NNPDF2.3
global PDF determination, by quantifying in each case the impact of different
theoretical assumptions on the output PDFs. We also study in each case the
implications for benchmark cross sections at the LHC. We find that the impact
in a global fit of a fixed-flavor number scheme is substantial, the impact of
higher twists is negligible, and the impact of nuclear corrections is moderate
and circumscribed.; Comment: 18 pages, 13 figures. Final version, to be published in Phys. Lett.
B. Tab. 2 added and Fig 13 updated. Several small improvements, including
revised discussion of Ref.[24]

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## PDF uncertainties on the W boson mass measurement from the lepton transverse momentum distribution

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Português

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We study the charged current Drell-Yan process and we evaluate the proton
parton densities uncertainties on the lepton transverse momentum distribution
and their impact on the determination of the W-boson mass. We consider the
global PDF sets CT10, MSTW2008CPdeut, NNPDF2.3, NNPDF3.0, MMHT2014, and apply
the PDF4LHC recipe to combine the individual results, obtaining an uncertainty
on MW that ranges between +-18 and +-24 MeV, depending on the final state,
collider energy and kind. We discuss the dependence of the uncertainty on the
acceptance cuts and the role of the individual parton densities in the final
result. We remark that some PDF sets predict an uncertainty on MW of O(10 MeV);
this encouraging result is spoiled, in the combined analysis of the different
sets, by an important spread of the central values predicted by each group.; Comment: version accepted for publication on Phys.Rev.D, one figure and two
references added

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## Multi-variate joint PDF for non-Gaussianities: exact formulation and generic approximations

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Português

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We provide an exact expression for the multi-variate joint probability
distribution function of non-Gaussian fields primordially arising from local
transformations of a Gaussian field. This kind of non-Gaussianity is generated
in many models of inflation. We apply our expression to the non- Gaussianity
estimation from Cosmic Microwave Background maps and the halo mass function
where we obtain analytical expressions. We also provide analytic approximations
and their range of validity. For the Cosmic Microwave Background we give a fast
way to compute the PDF which is valid up to 7{\sigma} for fNL values (both true
and sampled) not ruled out by current observations, which consists of
expressing the PDF as a combination of bispectrum and trispectrum of the
temperature maps. The resulting expression is valid for any kind of
non-Gaussianity and is not limited to the local type. The above results may
serve as the basis for a fully Bayesian analysis of the non-Gaussianity
parameter.; Comment: Matches accepted verion to JCAP; conclusions unchaged, extra
references added

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## Uncertainties on alpha_S in global PDF analyses and implications for predicted hadronic cross sections

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Português

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We determine the uncertainty on the strong coupling alpha_S due to the
experimental errors on the data fitted in global analysis of hard-scattering
data, within the standard framework of leading-twist fixed-order collinear
factorisation in the MSbar scheme, finding that alpha_S(M_Z^2) =
0.1202^{+0.0012}_{-0.0015} at next-to-leading order (NLO) and alpha_S(M_Z^2) =
0.1171^{+0.0014}_{-0.0014} at next-to-next-to-leading order (NNLO). We do not
address in detail the issue of the additional theory uncertainty on
alpha_S(M_Z^2), but an estimate is +/-0.003 at NLO and at most +/-0.002 at
NNLO. We investigate the interplay between uncertainties on alpha_S and
uncertainties on parton distribution functions (PDFs). We show, for the first
time, how both these sources of uncertainty can be accounted for simultaneously
in calculations of cross sections, and we provide eigenvector PDF sets with
different fixed alpha_S values to allow further studies by the general user. We
illustrate the application of these PDF sets by calculating cross sections for
W, Z, Higgs boson and inclusive jet production at the Tevatron and LHC.; Comment: 45 pages, 17 figures. Grids can be found at
http://projects.hepforge.org/mstwpdf/ and in LHAPDF V5.7.1. v2: version to
appear in EPJC

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## PDF uncertainties in WH production at Tevatron

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Português

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We apply a method proposed by members of CTEQ Collaboration to estimate the
uncertainty in associated $W$-Higgs boson production at Run II of the Tevatron
due to our imprecise knowledge of parton distribution functions. We find that
the PDF uncertainties for the signal and background rates are of the order 3%.
The PDF uncertainties for the important statistical quantities (significance of
the Higgs boson discovery, accuracy of the measurement of the (WH) cross
section) are smaller (1.5%) due to the strong correlation of the signal and
background.; Comment: A typo in Eq. (4) corrected

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## PDF fit in the fixed-flavor-number scheme

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 21/02/2012
Português

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We discuss the heavy-quark contribution to deep inelastic scattering in the
scheme with $n_f=3,4,5$ fixed flavors. Based on the recent ABM11 PDF analysis
of world data for deep-inelastic scattering and fixed-target data for the
Drell-Yan process with the running-mass definition for heavy quarks we show
that fixed flavor number scheme is sufficient for describing the
deep-inelastic-scattering data in the entire kinematic range. We compare with
other PDF sets and comment on the implications for measuring the strong
coupling constant $\alpha_s(M_Z)$.; Comment: 11 pages with 10 figures, to appear in the proceedings of the
"Ringberg Workshop: New Trends in HERA Physics 2011", Ringberg Castle,
Germany, 25-28 September, 2011

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## Uncertainties on alpha(S) in global PDF analyses and implications for predicted hadronic cross sections.

Fonte: Universidade de Cambridge
Publicador: Universidade de Cambridge

Tipo: Article; not applicable

Português

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We determine the uncertainty on the strong coupling S due to the experimental
errors on the data fitted in global analysis of hard-scattering data, within the standard
framework of leading-twist fixed-order collinear factorisation in the MS scheme,
finding that S(M2Z) = 0.1202+0.0012-0.0015
at next-to-leading order (NLO) and
S(M2Z) = 0.1171+0.0014?0.0014
at next-to-next-to-leading order (NNLO). We do not address in detail the issue of the
additional theory uncertainty on S(M2Z),
but an estimate is ?0.003 at NLO and at
most ?0.002 at NNLO. We investigate the interplay between uncertainties on S and
uncertainties on parton distribution functions (PDFs). We show, for the first time, how both these sources of uncertainty
can be accounted for simultaneously in calculations of cross sections, and we
provide eigenvector PDF sets with different fixed S values to allow further studies by
the general user. We illustrate the application of these PDF sets by
calculating cross sections for W, Z, Higgs boson and inclusive jet production at the
Tevatron and LHC.

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## Simulation of turbulent lifted methane jet flames: effects of air-dilution and transient flame propagation

Fonte: Elsevier
Publicador: Elsevier

Tipo: Article; accepted version

Português

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#Partially premixed combustion#Correlated joint PDF#Air dilution#Flame lift-off height#Flame stabilisation

This is the accepted manuscript. The final version will be available from Elsevier at: http://www.sciencedirect.com/science/article/pii/S001021801400279X.; Turbulent lifted methane jet flames with various air-dilution levels and a range
of inlet velocities are simulated. A partially premixed combustion model based
on premixed flamelets with presumed joint Probability Density Function (PDF) is
used. The joint PDF is obtained using a copula to include the statistical correlation
between mixture fraction, Z, and progress variable, c. The non-premixed combustion
effect is included using a simple algebraic model. Both steady and unsteady
RANS simulations are performed. The steady simulations show that the computed
lift-off heights agree well with measured values for a wide range of jet velocities
and air-dilution level. Both of the Z-c correlation and non-premixed combustion
effects are found to be important to get the correct lift-off height. Their individual
and combined effects are analysed systematically. The unsteady RANS results
indicate that multi-stage flame development, namely the initial expansion, flame
brush development, its propagation and final stabilisation, is captured reasonably
well in simulations. The various stages of temporal evolution of the flame brush edge is captured well and the agreement with experimental measurements is good.; The supports of Cambridge Overseas Trust and China Scholarship Council are
acknowledged by ZC. SR and NS acknowledge the support of MHI...

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## Modelling paradigms for MILD combustion

Fonte: Springer
Publicador: Springer

Tipo: Article; accepted version

Português

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#MILD combustion#Flameless combustion#Direct numerical simulation (DNS)#Perfectly stirred reactor (PSR)#presumed PDF#LES#RANS#Modelling

This is the accepted manuscript. The final version is available from Springer at http://link.springer.com/article/10.1007%2Fs12572-014-0106-x.; Three-dimensional Direct Numerical Simulation (DNS) data of methane-air MILD combustion
is analysed to study the behaviour of MILD reaction zones and to identify a suitable
modelling paradigm for MILD combustion. The combustion kinetics in the DNS
was modelled using a skeletal mechanism including non-unity Lewis number effects. The
reaction zones under MILD conditions are highly convoluted and contorted resulting in
their frequent interactions. This leads to combustion occurring over a large portion of
the computational volume and giving an appearance of distributed combustion. Three
paradigms, standard flamelets, mild flame elements (MIFEs) and PSR, along with a presumed
PDF model are explored to estimate the mean and filtered reaction rate in MILD
combustion. A beta function is used to estimate the presumed PDF shape. The variations
of species mass fractions and reaction rate with temperature computed using thesemodels
are compared to the DNS results. The PSR-based model is found to be appropriate, since
the conditional averages obtained from the DNS agree well with those obtained using the
PSR model. The flamelets model with MIFEs gives only a qualitative agreement because
it does not include the effects of reaction zone interactions.; YM acknowledges the financial support of Nippon Keidanren and Cambridge Overseas
Trust. EPSRC support is acknowledged by NS. This work made use of the facilities of HECToR...

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## Discrete pdf estimation in the presence of noise

Fonte: IEEE
Publicador: IEEE

Tipo: Book Section; PeerReviewed
Formato: application/pdf

Publicado em 03/09/2004
Português

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The problem of estimating a pdf from measurements has been widely studied by many researchers. However, most of the work was focused on estimating a probability density function of continuous random variables, especially in the absence of noise. In this paper, we consider a model for representing discrete probability density functions based on multirate dsp models. Using this model, we propose an efficient and stable scheme for pdf estimation
when the measurements are corrupted by independent additive
noise. This approach makes use of well-known results from multirate dsp theory, especially that of biorthogonal partners. Simulation results are given, which clearly show the advantage of the proposed method.

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