112 research outputs found
SEISMIC: A Self-Exciting Point Process Model for Predicting Tweet Popularity
Social networking websites allow users to create and share content. Big
information cascades of post resharing can form as users of these sites reshare
others' posts with their friends and followers. One of the central challenges
in understanding such cascading behaviors is in forecasting information
outbreaks, where a single post becomes widely popular by being reshared by many
users. In this paper, we focus on predicting the final number of reshares of a
given post. We build on the theory of self-exciting point processes to develop
a statistical model that allows us to make accurate predictions. Our model
requires no training or expensive feature engineering. It results in a simple
and efficiently computable formula that allows us to answer questions, in
real-time, such as: Given a post's resharing history so far, what is our
current estimate of its final number of reshares? Is the post resharing cascade
past the initial stage of explosive growth? And, which posts will be the most
reshared in the future? We validate our model using one month of complete
Twitter data and demonstrate a strong improvement in predictive accuracy over
existing approaches. Our model gives only 15% relative error in predicting
final size of an average information cascade after observing it for just one
hour.Comment: 10 pages, published in KDD 201
Vibrational analysis of flavone
In this study, the experimental and theoretical study on the structures and vibrations of flavone are presented. FT-IR and FT-Raman spectra of the molecule have been recorded in the 400-4000 cm-1 region and the 5-3500 cm-1 region, respectively. The molecular geometry and vibrational frequencies of flavone in the ground state have been calculated by using Density Functional method (B3LYP) in conjunction with 6-311++G(d, p) and 6-31++G(d) as basis sets. © TÜBİTAK
Molecular structure, vibrational spectral investigation and the confirmation analysis of 4-Methylesculetin molecule
WOS: 000333614200003In this work, FT-IR, FT-Raman, and FT-NMR spectra of 4-Methylesculetin molecule are presented for the first time. FT-IR, FT-Raman, and FT-NMR spectra of 4MEC have been recorded and analyzed. The FT-IR and FT-Raman spectra of this molecule are recorded at 4000-400 cm(-1) and 50-3500 cm(-1), respectively. The infrared vibrational frequencies, absolute intensities, potential energy profile, HOMO-LUMO plot and NBO analysis of the molecule have been also predicted using Becke's three-parameter hybrid B3LYP method in the density functional theory DFT method. Calculated and experimental data are in good agreement.Ahi Evran University Research FundAhi Evran University [FEN.4003.12.013]Y. Erdogdu would like to thank Ahi Evran University Research Fund for its financial support. Project Numbers: FEN.4003.12.013. Computing resources used in this work were provided by the National Center for High Performance Computing of Turkey (UYBHM)
Upper limits on neutrino masses from the 2dFGRS and WMAP: the role of priors
Solar, atmospheric, and reactor neutrino experiments have confirmed neutrino
oscillations, implying that neutrinos have non-zero mass, but without pinning
down their absolute masses. While it is established that the effect of
neutrinos on the evolution of cosmic structure is small, the upper limits
derived from large-scale structure data could help significantly to constrain
the absolute scale of the neutrino masses. In a recent paper the 2dF Galaxy
Redshift Survey (2dFGRS) team provided an upper limit m_nu,tot < 2.2 eV, i.e.
approximately 0.7 eV for each of the three neutrino flavours, or phrased in
terms of their contributioin to the matter density, Omega_nu/Omega_m < 0.16.
Here we discuss this analysis in greater detail, considering issues of assumed
'priors' like the matter density Omega_m and the bias of the galaxy
distribution with respect the dark matter distribution. As the suppression of
the power spectrum depends on the ratio Omega_nu/Omega_m, we find that the
out-of- fashion Mixed Dark Matter Model, with Omega_nu=0.2, Omega_m=1 and no
cosmological constant, fits the 2dFGRS power spectrum and the CMB data
reasonably well, but only for a Hubble constant H_0<50 km/s/Mpc. As a
consequence, excluding low values of the Hubble constant, e.g. with the HST Key
Project is important in order to get a strong constraint on the neutrino
masses. We also comment on the improved limit by the WMAP team, and point out
that the main neutrino signature comes from the 2dFGRS and the Lyman alpha
forest.Comment: 24 pages, 12 figures Minor changes to matched version published in
JCA
NF-KappaB expression correlates with apoptosis and angiogenesis in clear cell renal cell carcinoma tissues
<p>Abstract</p> <p>Background</p> <p>Clear cell renal cell carcinoma (ccRCC) is the most frequently encountered tumor in the adult kidney. Many factors are known to take part in the development and progression of this tumor. Nuclear factor kappa B (NF-κB) is a family of the genes that includes five members acting in events such as inflammation and apoptosis. In this study, the role of NF-κB (p50 subunit) in ccRCC and its relation to angiogenesis and apoptosis were investigated.</p> <p>Methods</p> <p>Formalin-fixed and paraffin embedded tissue blocks from 40 patients with ccRCC were studied. Expressions of NF-κB (p50), VEGF, EGFR, bc1-2 and p53 were detected immunohistochemically. The relationship of NF-κB with these markers and clinicopathological findings were evaluated.</p> <p>Results</p> <p>The expression of NF-κB was detected in 35 (85%), VEGF in 37 (92.5%), EGFR in 38 (95%), bc1-2 in 33 (82.5%) and p53 in 13 (32.5%) of 40 ccRCC patients. Statistical analyses revealed a significant relation between NF-κB expression and VEGF (p = 0.001), EGFR (p = 0.004), bc1-2 (p = 0.010) and p53 (p = 0.037). There was no significant correlation between NF-κB and such parameters as tumor grade, stage, age and sex.</p> <p>Conclusion</p> <p>The results of this study indicated that in ccRCC cases NF-κB was associated with markers of angiogenesis and apoptosis such as VEGF, EGFR, bc1-2 and p53. In addition, the results did not only suggest a close relationship between NF-κB and VEGF, EGFR, bc1-2 and p53 in ccRCC, but also indicate that NF-κB was a potential therapeutic target in the treatment of ccRCC resistant to chemotherapy.</p
The Signature of Large Scale Structures on the Very High Energy Gamma-Ray Sky
If the diffuse extragalactic gamma ray emission traces the large scale
structures of the universe, peculiar anisotropy patterns are expected in the
gamma ray sky. In particular, because of the cutoff distance introduced by the
absorption of 0.1-10 TeV photons on the infrared/optical background, prominent
correlations with the local structures within a range of few hundreds Mpc
should be present. We provide detailed predictions of the signal based on the
PSCz map of the local universe. We also use mock N-body catalogues complemented
with the halo model of structures to study some statistical features of the
expected signatures. The results are largely independent from cosmological
details, and depend mostly on the index of correlation (or bias) of the sources
with respect to the large scale distribution of galaxies. For instance, the
predicted signal in the case of a quadratic correlation (as it may happen for a
dark matter annihilation contribution to the diffuse gamma flux) differs
substantially from a linear correlation case, providing a complementary tool to
unveil the nature of the sources of the diffuse gamma ray emission. The chances
of the present and future space and ground based observatories to measure these
features are discussed.Comment: 26 pages, 9 figures; matches published versio
Outline of Fungi and fungus-like taxa
This article provides an outline of the classification of the kingdom Fungi (including fossil fungi. i.e. dispersed spores, mycelia, sporophores, mycorrhizas). We treat 19 phyla of fungi. These are Aphelidiomycota, Ascomycota, Basidiobolomycota, Basidiomycota, Blastocladiomycota, Calcarisporiellomycota, Caulochytriomycota, Chytridiomycota, Entomophthoromycota, Entorrhizomycota, Glomeromycota, Kickxellomycota, Monoblepharomycota, Mortierellomycota, Mucoromycota, Neocallimastigomycota, Olpidiomycota, Rozellomycota and Zoopagomycota. The placement of all fungal genera is provided at the class-, order- and family-level. The described number of species per genus is also given. Notes are provided of taxa for which recent changes or disagreements have been presented. Fungus-like taxa that were traditionally treated as fungi are also incorporated in this outline (i.e. Eumycetozoa, Dictyosteliomycetes, Ceratiomyxomycetes and Myxomycetes). Four new taxa are introduced: Amblyosporida ord. nov. Neopereziida ord. nov. and Ovavesiculida ord. nov. in Rozellomycota, and Protosporangiaceae fam. nov. in Dictyosteliomycetes. Two different classifications (in outline section and in discussion) are provided for Glomeromycota and Leotiomycetes based on recent studies. The phylogenetic reconstruction of a four-gene dataset (18S and 28S rRNA, RPB1, RPB2) of 433 taxa is presented, including all currently described orders of fungi
Nurses' perceptions of aids and obstacles to the provision of optimal end of life care in ICU
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