884 research outputs found
Analysis of ecosystem services provision in the Colombian Amazon using participatory research and mapping techniques
Over the last two decades indigenous peoples in the lower Caquetá River basin in Colombia have experienced detrimental changes in the provision of important ecosystem services in ways that have significant implications for the maintenance of their traditional livelihoods. To assess these changes we conducted eight participatory mapping activities and convened 22 focus group discussions. We focused the analysis on two types of change: (1) changes in the location of ecosystem services provisioning areas and (2) changes in the stock of ecosystem services. The focal ecosystem services include services such as provision of food, raw materials and medicinal resources. Results from the study show that in the past two decades the demand for food and raw materials has intensified and, as a result, locations of provisioning areas and the stocks of ecosystem services have changed. We found anecdotal evidence that these changes correlate well with socio-economic factors such as greater need for income generation, change in livelihood practices and consumption patterns. We discuss the use of participatory mapping techniques in the context of marginalized and data-poor regions. We also show how this kind of information can strengthen existing ecosystem-based management strategies used by indigenous peoples in the Colombian Amazon
Functional characterization of E- and P-cadherin in invasive breast cancer cells
Background: Alterations in the cadherin-catenin adhesion complexes are involved in tumor initiation, progression and metastasis. However, the functional implication of distinct cadherin types in breast cancer biology is still poorly understood. Methods: To compare the functional role of E-cadherin and P-cadherin in invasive breast cancer, we stably transfected these molecules into the MDA-MB-231 cell line, and investigated their effects on motility, invasion and gene expression regulation. Results: Expression of either E-and P-cadherin significantly increased cell aggregation and induced a switch from fibroblastic to epithelial morphology. Although expression of these cadherins did not completely reverse the mesenchymal phenotype of MDA-MB-231 cells, both E-and P-cadherin decreased fibroblast-like migration and invasion through extracellular matrix in a similar way. Moreover, microarray gene expression analysis of MDA-MB-231 cells after expression of E-and P-cadherins revealed that these molecules can activate signaling pathways leading to significant changes in gene expression. Although the expression patterns induced by E-and P-cadherin showed more similarities than differences, 40 genes were differentially modified by the expression of either cadherin type. Conclusion: E-and P-cadherin have similar functional consequences on the phenotype and invasive behavior of MDA-MB-231 cells. Moreover, we demonstrate for the first time that these cadherins can induce both common and specific gene expression programs on invasive breast cancer cells. Importantly, these identified genes are potential targets for future studies on the functional consequences of altered cadherin expression in human breast cancer
Entanglement of single-photons and chiral phonons in atomically thin WSe
Quantum entanglement is a fundamental phenomenon which, on the one hand,
reveals deep connections between quantum mechanics, gravity and the space-time;
on the other hand, has practical applications as a key resource in quantum
information processing. While it is routinely achieved in photon-atom
ensembles, entanglement involving the solid-state or macroscopic objects
remains challenging albeit promising for both fundamental physics and
technological applications. Here, we report entanglement between collective,
chiral vibrations in two-dimensional (2D) WSe host --- chiral phonons (CPs)
--- and single-photons emitted from quantum dots (QDs) present in it. CPs which
carry angular momentum were recently observed in WSe and are a
distinguishing feature of the underlying honeycomb lattice. The entanglement
results from a "which-way" scattering process, involving an optical excitation
in a QD and doubly-degenerate CPs, which takes place via two indistinguishable
paths. Our unveiling of entanglement involving a macroscopic, collective
excitation together with strong interaction between CPs and QDs in 2D materials
opens up ways for phonon-driven entanglement of QDs and engineering chiral or
non-reciprocal interactions at the single-photon level
Radioterapia de Intensidad modulada versus radioterapia tridimensional en pacientes con cáncer de esófago inoperable: Resultados clínicos, toxicidades y análisis dosimétrico
INTRODUCCIÓN: El cáncer de esófago (CE) es una enfermedad severa, sin embargo, hay un porcentaje
de pacientes con enfermedad locorregional que son potencialmente curables. Hay algunos pacientes en los
que está claro que la cirugía no es posible, y por lo tanto la quimiorradiación definitiva debe ser usada. Con
la incorporación de técnicas de radioterapia de intensidad modulada (IMRT) es posible disminuir la dosis
que reciben los órganos a riesgo. Esto es de suma importancia ya que en estudios publicados recientemente
se demostró que la dosis cardíaca (V30<45%) y pulmonar (Dmedia<10Gy) son predictores independientes
de sobrevida global.
OBJETIVO: demostrar la experiencia institucional de los pacientes inoperables tratados con
radioquimioterapia definitiva, comparando resultados clínicos, toxicidades y análisis dosimétrico de las
técnicas tridimensional (3D) vs Radioterapia de Intensidad Modulada (IMRT).
MATERIAL Y MÉTODO: Éste es un estudio descriptivo, retrospectivo y observacional de pacientes
tratados con radioquimioterapia definitiva en Centro de Radioterapia Deán Funes, Córdoba, Argentina.
Treinta y dos pacientes fueron tratados entre junio de 2016 y marzo de 2019. Radioterapia fue administrada
con las técnicas IMRT y 3D a dosis comprendida entre 45-50Gy. Se utilizó el método de Kaplan-Meier
para estimar la supervivencia y sobrevida libre de progresión. El análisis univariado (UVA) se realizó con
modelo de riesgos proporcionales de Cox. Se utilizó la prueba de chi-cuadrado para las variables
categóricas.
RESULTADOS La media de seguimiento fue de 17.4 meses (rango 0.1-54.5 meses). La mediana de edad
de los pacientes fue de 74 años (rango, 51 a 89 años), con PS 0-1 (91%). La mitad de los pacientes
recibieron radioterapia IMRT. La sobrevida global a un año fue de 47% (15 sobre 32 pacientes) y a dos
años 25% (8 sobre 32 pacientes). La tasa de recaída local fue de 47% (15 sobre 32 pacientes). En el análisis
univariado solo la edad mayor a 75 años fue predictora de peor sobrevida (p0.01, RR 2.82). Con IMRT
hubo mayor sobrevida promedio (19 vs 15 meses), sin embargo, no se vio reflejado a una significancia
estadística (p: 0.96), con IMRT fue mayor la sobrevida libre de progresión, sin embargo, no fue
estadísticamente significativo (p: 0.08). Con IMRT se disminuyó la dosis media cardíaca un 17% (p=0.01)
y la dosis pulmonar media 5% (p= 0.44). IMRT permitió conseguir de manera significativa un V30 < 45%
(0.01). Toxicidad G1-2 fueron observadas en 43.8% de los pacientes y toxicidades ≥ grado 3 fue observada
solo en 9.4% de los pacientes, no habiendo diferencias significativas entre las distintas técnicas aplicadas
(p 1.72 y 1 respectivamente).
CONCLUSIONES: Radioquimioterapia definitiva es el tratamiento estándar en cáncer de esófago
escamoso localmente avanzado siendo un enfoque seguro y con buena tolerancia para aquellos pacientes
inoperables, a esto se suma que con IMRT se ofrecen mejores resultados dosimétricos y mayor protección
de órganos a riesgo, lo cual podría estar implicado, con un mayor seguimiento y número de pacientes a
mejores supervivencias para aquellos pacientes con buenos resultados oncológicos
Measurement of the ratio of branching fractions BR(B0 -> K*0 gamma)/BR(Bs0 -> phi gamma)
The ratio of branching fractions of the radiative B decays B0 -> K*0 gamma
and Bs0 -> phi gamma has been measured using 0.37 fb-1 of pp collisions at a
centre of mass energy of sqrt(s) = 7 TeV, collected by the LHCb experiment. The
value obtained is BR(B0 -> K*0 gamma)/BR(Bs0 -> phi gamma) = 1.12 +/- 0.08
^{+0.06}_{-0.04} ^{+0.09}_{-0.08}, where the first uncertainty is statistical,
the second systematic and the third is associated to the ratio of fragmentation
fractions fs/fd. Using the world average for BR(B0 -> K*0 gamma) = (4.33 +/-
0.15) x 10^{-5}, the branching fraction BR(Bs0 -> phi gamma) is measured to be
(3.9 +/- 0.5) x 10^{-5}, which is the most precise measurement to date.Comment: 15 pages, 1 figure, 2 table
Search for CP violation in decays
A model-independent search for direct CP violation in the Cabibbo suppressed
decay in a sample of approximately 370,000 decays is
carried out. The data were collected by the LHCb experiment in 2010 and
correspond to an integrated luminosity of 35 pb. The normalized Dalitz
plot distributions for and are compared using four different
binning schemes that are sensitive to different manifestations of CP violation.
No evidence for CP asymmetry is found.Comment: 13 pages, 8 figures, submitted to Phys. Rev.
Opposite-side flavour tagging of B mesons at the LHCb experiment
The calibration and performance of the oppositeside
flavour tagging algorithms used for the measurements
of time-dependent asymmetries at the LHCb experiment
are described. The algorithms have been developed using
simulated events and optimized and calibrated with
B
+ →J/ψK
+, B0 →J/ψK
∗0 and B0 →D
∗−
μ
+
νμ decay
modes with 0.37 fb−1 of data collected in pp collisions
at
√
s = 7 TeV during the 2011 physics run. The oppositeside
tagging power is determined in the B
+ → J/ψK
+
channel to be (2.10 ± 0.08 ± 0.24) %, where the first uncertainty
is statistical and the second is systematic
Observation of excited Lambda_b0 baryons
Using pp collision data corresponding to 1.0 fb-1 integrated luminosity
collected by the LHCb detector, two narrow states are observed in the
Lambda_b0pi+pi- spectrum with masses 5911.97 +- 0.12(stat) +- 0.02(syst) +-
0.66(Lambda_b0 mass) MeV/c^2 and 5919.77 +- 0.08(stat) +- 0.02(syst) +-
0.66(Lambda_b0 mass) MeV/c^2. The significances of the observations are 5.2 and
10.2 standard deviations, respectively. These states are interpreted as the
orbitally-excited Lambda_b0 baryons, Lambda_b*0(5912) and Lambda_b*0(5920).Comment: Replaced by version published in Phys. Rev. Lett, modified fit with
better mass resolution treatmen
Strong constraints on the rare decays Bs -> mu+ mu- and B0 -> mu+ mu-
A search for Bs -> mu+ mu- and B0 -> mu+ mu- decays is performed using 1.0
fb^-1 of pp collision data collected at \sqrt{s}=7 TeV with the LHCb experiment
at the Large Hadron Collider. For both decays the number of observed events is
consistent with expectation from background and Standard Model signal
predictions. Upper limits on the branching fractions are determined to be BR(Bs
-> mu+ mu-) mu+ mu-) < 1.0 (0.81) x 10^-9 at
95% (90%) confidence level.Comment: 2+6 pages; 4 figures; Accepted for publication in Physical Review
Letter
Measurement of the CP-violating phase phi_s in the decay Bs->J/psi phi
We present a measurement of the time-dependent CP-violating asymmetry in B_s
-> J/psi phi decays, using data collected with the LHCb detector at the LHC.
The decay time distribution of B_s -> J/psi phi is characterized by the decay
widths Gamma_H and Gamma_L of the heavy and light mass eigenstates of the
B_s-B_s-bar system and by a CP-violating phase phi_s. In a sample of about 8500
B_s -> J/psi phi events isolated from 0.37 fb^-1 of pp collisions at sqrt(s)=7
TeV we measure phi_s = 0.15 +/- 0.18 (stat) +/- 0.06 (syst) rad. We also find
an average B_s decay width Gamma_s == (Gamma_L + Gamma_H)/2 = 0.657 +/- 0.009
(stat) +/- 0.008 (syst) ps^-1 and a decay width difference Delta Gamma_s ==
Gamma_L - Gamma_H} = 0.123 +/- 0.029 (stat) +/- 0.011 (syst) ps^-1. Our
measurement is insensitive to the transformation (phi_s,DeltaGamma_s --> pi -
phi_s, - Delta Gamma_s.Comment: 9 pages, 3 figure
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