3,691 research outputs found
Geochemical assessment of metals in fluvial systems affected by anthropogenic activities in the Iron Quadrangle.
O presente estudo foi realizado na bacia hidrogr?fica do Rio do Peixe,
Quadril?tero Ferr?fero (QF), em Minas Gerais. Essa bacia apresenta um cen?rio
geol?gico distinto e atividades antr?picas diversificadas, como a minera??o de
ferro, ouro e gemas, a agropecu?ria e a silvicultura. O principal objetivo desta
pesquisa foi investigar as poss?veis fontes de contribui??es antropog?nicas dos
metais em sedimentos de fundo. Para isso, foram realizadas duas campanhas
com amostragens de sedimentos de fundo em 12 pontos da bacia, nos meses
de mar?o e julho de 2015. A partir da t?cnica anal?tica de espectrometria de
emiss?o ?ptica com plasma, foram detectadas concentra??es de Al, Ca, Co,
Cr, Cu, Fe, Mn, Ni, Pb, Ti e Zn nos sedimentos de fundo. Os resultados dos
indicadores da qualidade dos sedimentos fator de contamina??o (FC), fator
de enriquecimento (FE) e ?ndice de geoacumula??o (IGEO) demonstraram
que h? interfer?ncias antr?picas, sendo as atividades miner?rias e industriais,
o despejo de efluentes dom?sticos e o uso e a ocupa??o do solo inapropriado
apontados como as principais fontes de contamina??o de metais da bacia.The present study was carried out in the river basin area of Rio do Peixe,
Iron Quadrangle, in Minas Gerais, Brazil. This basin presents geological
scenario and diversified anthropic activities, such as iron, gold and gems
mining, agriculture, and forestry. The main objective of this research
was to investigate the possible sources of anthropogenic contributions
of metals in bottom sediments. Thus, two surveys were carried out
on bottom sediments at twelve basin sites from March to July of 2015.
Based on the plasma optical emission spectrometry analytical technique,
we found concentrations of Al, Ca, Co, Cr, Cu, Fe, Mn, Ni, Pb, Ti and Zn
in the bottom sediments. The results of the FC, FE and IGEO sediment
quality indicators showed that there are anthropic interferences, in which
mining and industrial activities, disposal of domestic effluents and use
and occupation of inappropriate soil are identified as the main sources of
metals contamination of the basin
Measuring, Understanding, and Classifying News Media Sympathy on Twitter after Crisis Events
This paper investigates bias in coverage between Western and Arab media on
Twitter after the November 2015 Beirut and Paris terror attacks. Using two
Twitter datasets covering each attack, we investigate how Western and Arab
media differed in coverage bias, sympathy bias, and resulting information
propagation. We crowdsourced sympathy and sentiment labels for 2,390 tweets
across four languages (English, Arabic, French, German), built a regression
model to characterize sympathy, and thereafter trained a deep convolutional
neural network to predict sympathy. Key findings show: (a) both events were
disproportionately covered (b) Western media exhibited less sympathy, where
each media coverage was more sympathetic towards the country affected in their
respective region (c) Sympathy predictions supported ground truth analysis that
Western media was less sympathetic than Arab media (d) Sympathetic tweets do
not spread any further. We discuss our results in light of global news flow,
Twitter affordances, and public perception impact.Comment: In Proc. CHI 2018 Papers program. Please cite: El Ali, A., Stratmann,
T., Park, S., Sch\"oning, J., Heuten, W. & Boll, S. (2018). Measuring,
Understanding, and Classifying News Media Sympathy on Twitter after Crisis
Events. In Proceedings of the 2018 CHI Conference on Human Factors in
Computing Systems (CHI '18). ACM, New York, NY, USA. DOI:
https://doi.org/10.1145/3173574.317413
Model for in vivo progression of tumors based on co-evolving cell population and vasculature
With countless biological details emerging from cancer experiments, there is a growing need for minimal mathematical models which simultaneously advance our understanding of single tumors and metastasis, provide patient-personalized predictions, whilst avoiding excessive hard-to-measure input parameters which complicate simulation, analysis and interpretation. Here we present a model built around a co-evolving resource network and cell population, yielding good agreement with primary tumors in a murine mammary cell line EMT6-HER2 model in BALB/c mice and with clinical metastasis data. Seeding data about the tumor and its vasculature from in vivo images, our model predicts corridors of future tumor growth behavior and intervention response. A scaling relation enables the estimation of a tumor's most likely evolution and pinpoints specific target sites to control growth. Our findings suggest that the clinically separate phenomena of individual tumor growth and metastasis can be viewed as mathematical copies of each other differentiated only by network structure
Profiling the immune landscape in mucinous ovarian carcinoma
Objective: Mucinous ovarian carcinoma (MOC) is a rare histotype of ovarian cancer, with low response rates to standard chemotherapy, and very poor survival for patients diagnosed at advanced stage. There is a limited understanding of the MOC immune landscape, and consequently whether immune checkpoint inhibitors could be considered for a subset of patients. Methods: We performed multicolor immunohistochemistry (IHC) and immunofluorescence (IF) on tissue microarrays in a cohort of 126 MOC patients. Cell densities were calculated in the epithelial and stromal components for tumor-associated macrophages (CD68+/PD-L1+, CD68+/PD-L1-), T cells (CD3+/CD8-, CD3+/CD8+), putative T-regulatory cells (Tregs, FOXP3+), B cells (CD20+/CD79A+), plasma cells (CD20-/CD79a+), and PD-L1+ and PD-1+ cells, and compared these values with clinical factors. Univariate and multivariable Cox Proportional Hazards assessed overall survival. Unsupervised k-means clustering identified patient subsets with common patterns of immune cell infiltration. Results: Mean densities of PD1+ cells, PD-L1- macrophages, CD4+ and CD8+ T cells, and FOXP3+ Tregs were higher in the stroma compared to the epithelium. Tumors from advanced (Stage III/IV) MOC had greater epithelial infiltration of PD-L1- macrophages, and fewer PD-L1+ macrophages compared with Stage I/II cancers (p = 0.004 and p = 0.014 respectively). Patients with high epithelial density of FOXP3+ cells, CD8+/FOXP3+ cells, or PD-L1- macrophages, had poorer survival, and high epithelial CD79a + plasma cells conferred better survival, all upon univariate analysis only. Clustering showed that most MOC (86%) had an immune depleted (cold) phenotype, with only a small proportion (11/76,14%) considered immune inflamed (hot) based on T cell and PD-L1 infiltrates. Conclusion: In summary, MOCs are mostly immunogenically âcoldâ, suggesting they may have limited response to current immunotherapies
Observation of two new baryon resonances
Two structures are observed close to the kinematic threshold in the mass spectrum in a sample of proton-proton collision data, corresponding
to an integrated luminosity of 3.0 fb recorded by the LHCb experiment.
In the quark model, two baryonic resonances with quark content are
expected in this mass region: the spin-parity and
states, denoted and .
Interpreting the structures as these resonances, we measure the mass
differences and the width of the heavier state to be
MeV,
MeV,
MeV, where the first and second
uncertainties are statistical and systematic, respectively. The width of the
lighter state is consistent with zero, and we place an upper limit of
MeV at 95% confidence level. Relative
production rates of these states are also reported.Comment: 17 pages, 2 figure
Measurement of the mass and lifetime of the baryon
A proton-proton collision data sample, corresponding to an integrated
luminosity of 3 fb collected by LHCb at and 8 TeV, is used
to reconstruct , decays. Using the , decay mode for calibration, the lifetime ratio and absolute
lifetime of the baryon are measured to be \begin{align*}
\frac{\tau_{\Omega_b^-}}{\tau_{\Xi_b^-}} &= 1.11\pm0.16\pm0.03, \\
\tau_{\Omega_b^-} &= 1.78\pm0.26\pm0.05\pm0.06~{\rm ps}, \end{align*} where the
uncertainties are statistical, systematic and from the calibration mode (for
only). A measurement is also made of the mass difference,
, and the corresponding mass, which
yields \begin{align*} m_{\Omega_b^-}-m_{\Xi_b^-} &= 247.4\pm3.2\pm0.5~{\rm
MeV}/c^2, \\ m_{\Omega_b^-} &= 6045.1\pm3.2\pm 0.5\pm0.6~{\rm MeV}/c^2.
\end{align*} These results are consistent with previous measurements.Comment: 11 pages, 5 figures, All figures and tables, along with any
supplementary material and additional information, are available at
https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-008.htm
Study of and decays and determination of the CKM angle
We report a study of the suppressed and favored
decays, where the neutral meson is detected
through its decays to the and CP-even and
final states. The measurement is carried out using a proton-proton
collision data sample collected by the LHCb experiment, corresponding to an
integrated luminosity of 3.0~fb. We observe the first significant
signals in the CP-even final states of the meson for both the suppressed
and favored modes, as well as
in the doubly Cabibbo-suppressed final state of the decay. Evidence for the ADS suppressed decay , with , is also presented. From the observed
yields in the , and their
charge conjugate decay modes, we measure the value of the weak phase to be
. This is one of the most precise
single-measurement determinations of to date.Comment: 22 pages, 9 figures; All figures and tables, along with any
supplementary material and additional information, are available at
https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-020.htm
Measurement of the CP-violating phase \phi s in Bs->J/\psi\pi+\pi- decays
Measurement of the mixing-induced CP-violating phase phi_s in Bs decays is of
prime importance in probing new physics. Here 7421 +/- 105 signal events from
the dominantly CP-odd final state J/\psi pi+ pi- are selected in 1/fb of pp
collision data collected at sqrt{s} = 7 TeV with the LHCb detector. A
time-dependent fit to the data yields a value of
phi_s=-0.019^{+0.173+0.004}_{-0.174-0.003} rad, consistent with the Standard
Model expectation. No evidence of direct CP violation is found.Comment: 15 pages, 10 figures; minor revisions on May 23, 201
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