669 research outputs found
Opening up the Quantum Three-Box Problem with Undetectable Measurements
One of the most striking features of quantum mechanics is the profound effect
exerted by measurements alone. Sophisticated quantum control is now available
in several experimental systems, exposing discrepancies between quantum and
classical mechanics whenever measurement induces disturbance of the
interrogated system. In practice, such discrepancies may frequently be
explained as the back-action required by quantum mechanics adding quantum noise
to a classical signal. Here we implement the 'three-box' quantum game of
Aharonov and Vaidman in which quantum measurements add no detectable noise to a
classical signal, by utilising state-of-the-art control and measurement of the
nitrogen vacancy centre in diamond.
Quantum and classical mechanics then make contradictory predictions for the
same experimental procedure, however classical observers cannot invoke
measurement-induced disturbance to explain this discrepancy. We quantify the
residual disturbance of our measurements and obtain data that rule out any
classical model by > 7.8 standard deviations, allowing us for the first time to
exclude the property of macroscopic state-definiteness from our system. Our
experiment is then equivalent to a Kochen-Spekker test of quantum
non-contextuality that successfully addresses the measurement detectability
loophole
Field enhancement and spectral features of hexagonal necklaces of silver nanoparticles for enhanced nonlinear optical processes
Access to the online abstract in the journal: https://doi.org/10.1364/OE.26.022394
© 2018 Optical Society of America. Users may use, reuse, and build upon the article, or use the article for text or data mining, so long as such uses are for non-commercial purposes and appropriate attribution is maintained. All other rights are reservedThe nonlinear properties of hybrid metallic-dielectric systems are attracting great interest due to their potential for the enhancement of frequency conversion processes at nanoscale dimensions. In this work, we theoretically and experimentally address the correlation between the near field distribution of hexagonal plasmonic necklaces of silver nanoparticles formed on the surface of a LiNbO3 crystal and the second harmonic generation (SHG) produced by this nonlinear crystal in the vicinities of the necklaces. The spectral response of the hexagonal necklaces does not depend on the polarization direction and is characterized by two main modes, the absorptive high-energy mode located in the UV spectral region and the lower energy mode, which is strongly radiant and extends from the visible to the near infrared region. We show that the spatial distribution of the enhanced SHG is consistent with the local field related to the low energy plasmon mode, which spectrally overlaps the fundamental beam. The results are in agreement with the low absorption losses of this mode and the two-photon character of the nonlinear process and provide deeper insight in the connection between the linear and nonlinear optical properties of the hybrid plasmonic-ferroelectric system. The study also highlights the potential of hexagonal necklaces as useful plasmonic platforms for enhanced optical processes at the nanoscaleSpanish Ministry of Economy and Competitiveness (MINECO) under project MAT2016-
76106-R and the Comunidad de Madrid (grant S2013/MIT-2740). C.T. acknowledges
funding from the VILLUM Foundation (Villum Investigator, grant no. 16498). L.E.B and
M.O.R also acknowledges financial support from the Spanish Ministry of Economy and
Competitiveness, through The “María de Maeztu” Programme for Units of Excellence in
R&D (MDM-2014-0377
Políticas del blanqueamiento: escenografías del despojo urbano en Guadalajara
En este trabajo nos proponemos describir y problematizar el papel que juegan las políticas culturales en las estrategias de especulación y elitización del territorio en los centros históricos. Procesos que, a su vez, tienen como una de sus consecuencias más importantes la segregación racial y de clase en las metrópolis contemporáneas. Para ello, analizamos el caso concreto del Centro Histórico de Guadalajara desde una mirada que articula diversos actores y proyectos culturales, inmobiliarios y vecinales, así como sus implicaciones en las dinámicas urbanas del centro y la periferia
Major gene expression changes and epigenetic remodelling in Nile tilapia muscle after just one generation of domestication
The historically recent domestication of fishes has been essential to meet the protein demands of a growing human population. Selection for traits of interest during domestication is a complex process whose epigenetic basis is poorly understood. Cytosine hydroxymethylation is increasingly recognized as an important DNA modification involved in epigenetic regulation. In the present study, we investigated if hydroxymethylation plays a role in fish domestication and demonstrated for the first time at a genome-wide level and single nucleotide resolution that the muscle hydroxymethylome changes after a single generation of Nile tilapia (Oreochromis niloticus, Linnaeus) domestication. The overall decrease in hydroxymethylcytosine levels was accompanied by the downregulation of 2015 genes in fish reared in captivity compared to their wild progenitors. In contrast, several myogenic and metabolic genes that can affect growth potential were upregulated. There were 126 differentially hydroxymethylated cytosines between groups, which were not due to genetic variation; they were associated with genes involved in immune-, growth- and neuronal-related pathways. Taken together, our data unveil a new role for DNA hydroxymethylation in epigenetic regulation of fish domestication with impact in aquaculture and implications in artificial selection, environmental adaptation and genome evolution
Mapping dynamical systems onto complex networks
A procedure to characterize chaotic dynamical systems with concepts of
complex networks is pursued, in which a dynamical system is mapped onto a
network. The nodes represent the regions of space visited by the system, while
edges represent the transitions between these regions. Parameters used to
quantify the properties of complex networks, including those related to higher
order neighborhoods, are used in the analysis. The methodology is tested for
the logistic map, focusing the onset of chaos and chaotic regimes. It is found
that the corresponding networks show distinct features, which are associated to
the particular type of dynamics that have generated them.Comment: 13 pages, 8 eps files in 5 figure
Estudio sistemático, morfométrico y biogeográfico de <i>Blainia gregaria</i> Walcott, trilobite cámbrico medio de la Precordillera argentina
Se reconoce por primera vez en la Precordillera argentina el trilobite Blainia gregaria Walcott, del Cámbrico medio (Series 3). Los ejemplares estudiados fueron hallados en el tramo superior de la Formación La Laja, con litofacies de plataforma carbonática, aflorante en la Precordillera Oriental de San Juan. El presente trabajo se basa en dos perfiles ubicados en el cerro Tres Marías (sierra de Marquesado), y en la quebrada de Zonda (sierra Chica de Zonda). Los trilobites coleccionados están compuestos por 1.202 ejemplares (632 de la quebrada de Zonda y 570 del cerro Tres Marías) integrados por 563 pigidios y 639 cranidios. El estudio biométrico realizado en los especímenes precordilleranos de Blainia gregaria se basó en la colección del cerro Tres Marías (205 cranidios y 365 pigidios), hallada en 22 niveles estratigráficos distribuidos a lo largo de 155m de espesor columnar (15m cuspidales del Miembro Soldano, 100m del Miembro Rivadavia y 40m basales del Miembro Juan Pobre). El análisis morfométrico muestra relaciones bivariables que dan una nube de puntos muy similares, con rectas de regresión únicas, con los coeficientes de correlación bajos, que son compatibles con la idea de variabilidad intraespecífica. Se reconocen 6 morfotipos (3 cranidios y 3 pigidios) que aparecen juntos en la misma colección. Esto evidencia que es una especie extraordinariamente polimórfica, y nos lleva a proponer una extensa lista sinonímica con más de 30 especies de América del Norte, anteriormente agrupadas en los géneros Blainia Walcott y Glyphaspis Poulsen. La distribución biogeográfica de Blainia gregaria, así redefinida, muestra que esta especie poseía una amplia tolerancia ecológica a los diversos ambientes de las plataformas carbonáticas que rodeaban a Laurentia durante el Cámbrico medio. Su presencia en Precordillera es una evidencia de la estrecha relación que tiene el Terrane Precordillera con Laurentia.Simposio I: 2º Simposio de bioestratigrafía y eventos del Paleozoico inferiorFacultad de Ciencias Naturales y Muse
Evolution of E2 transition strength in deformed hafnium isotopes from new measurements on Hf, Hf, and Hf
The available data for E2 transition strengths in the region between
neutron-deficient Hf and Pt isotopes are far from complete. More and precise
data are needed to enhance the picture of structure evolution in this region
and to test state-of-the-art nuclear models. In a simple model, the maximum
collectivity is expected at the middle of the major shell. However, for actual
nuclei, this picture may no longer be the case, and one should use a more
realistic nuclear-structure model. We address this point by studying the
spectroscopy of Hf. We remeasure the 2^+_1 half-lives of 172,174,176Hf, for
which there is some disagreement in the literature. The main goal is to
measure, for the first time, the half-lives of higher-lying states of the
rotational band. The new results are compared to a theoretical calculation for
absolute transition strengths. The half-lives were measured using \gamma-\gamma
and conversion-electron-\gamma delayed coincidences with the fast timing
method. For the determination of half-lives in the picosecond region, the
generalized centroid difference method was applied. For the theoretical
calculation of the spectroscopic properties, the interacting boson model is
employed, whose Hamiltonian is determined based on microscopic energy-density
functional calculations. The measured 2^+_1 half-lives disagree with results
from earlier \gamma-\gamma fast timing measurements, but are in agreement with
data from Coulomb excitation experiments and other methods. Half-lives of the
4^+_1 and 6^+_1 states were measured, as well as a lower limit for the 8^+_1
states. We show the importance of the mass-dependence of effective boson charge
in the description of E2 transition rates in chains of nuclei. It encourages
further studies of the microscopic origin of this mass dependence. New data on
transition rates in nuclei from neighboring isotopic chains could support these
studies.Comment: 16 pages, 16 figures, 7 tables; Abstract shortened due to character
limi
Study of morphological and chemical changes of aligned zinc oxide nanorods growth by vapour phase transport on chemical bath deposited buffer layers
c-axis aligned ZnO nanorods were deposited by vapour phase transport on textured chemical bath deposited buffer layers. In this work we examine the role of the buffer layer and how it influences the vapour phase transport deposition process using both scanning and scanning transmission electron microscopes and related techniques. Vapour phase transport deposition on chemical bath deposited
buffer is a complex growth process with many simultaneously effects including; (i) substantial morphological transformation at high temperature, which influences the base of the nanorods; (ii) the formation of a mixed amorphous / crystalline ZnxSi1-xOy interface during the vapour phase transport growth on silicon substrates; (iii) the overgrowth of the ZnO seed layers, by the silica interface rendering them inactive for nanorod nucleation, suggesting there is a minimum critical thickness ZnO buffer layer necessary for vapour phase transport growth of ZnO nanorods on silicon substrates. We discuss the relative importance of these effects on the overall growth process and use this understanding to explain previous results in the literature
Clinical factors associated with high glycemic variability defined by coefficient of variation in patients with type 2 diabetes
Antecedentes: La Variabilidad Glucémica Alta (VHG) ha convertirse en un predictor más fuerte de hipoglucemia. Sin embargo, aún se desconocen los factores clínicos asociados con el VHG.
Objetivo:Determinar las variables clínicas que se asociaron con un coeficiente de variación (CV) superior al 36% evaluado mediante monitorización continua de glucosa (MCG) en un grupo de pacientes con diabetes mellitus.
Métodos: Se evaluó una cohorte de pacientes con diabetes tipo 2 (T2D). Se evaluaron variables demográficas, HbA1c, tasa de filtración glomerular (TFG) y régimen de tratamiento. Se realizó un análisis bivariado, para evaluar la asociación entre la variable resultado (CV > 36%) y cada una de las variables independientes. Se construyó un modelo multivariado para evaluar las asociaciones después de controlar las variables de confusión.
Resultados:Se analizaron los datos de MCG de 274 pacientes. CV> 36% estuvo presente en 56 pacientes (20,4%). En el análisis bivariado se incluyeron variables demográficas y clínicas, como tiempo desde el diagnóstico, antecedente de hipoglucemia, A1c, FG y tratamiento instaurado. En el análisis multivariante, FG 9% (OR 2,81; IC 1,05,7,51; p:0,04) y antecedentes de hipoglucemia (OR 2,09; IC 1,02, 4,32; p: 0,04) se asociaron con VHG. El tratamiento con iDPP4 (OR 0,39; IC 0,19, 0,82; p: 0,01) y AGLP1 (OR 0,08; IC 0,01, 0,68; p: 0,02) se asoció inversamente con la VG.
Conclusión:Variables clínicas como FG 9% y antecedentes de hipoglucemia se asocian a un VG alto. Nuestros datos sugieren que el uso de tecnología y tratamientos capaces de reducir la variabilidad glucémica podría ser útil en esta población para reducir el riesgo de hipoglucemia y mejorar el control glucémico.Q3Background: High glycemic Variability (HGV) has become a stronger predictor of hypoglycemia. However, clinical factors associate with HGV still are unknown.
Objective: To determine clinical variables that were associated with a coefficient of variation (CV) above 36% evaluated by continuous glucose monitoring (CGM) in a group of patients with diabetes mellitus.
Methods: A cohort of patients with type 2 diabetes (T2D) was evaluated. Demographic variables, HbA1c, glomerular filtration rate (GFR) and treatment regimen were assessed. A bivariate analysis was performed, to evaluate the association between the outcome variable (CV> 36%) and each of the independent variables. A multivariate model was constructed to evaluate associations after controlling for confounding variables.
Results: CGM data from 274 patients were analyzed. CV> 36% was present in 56 patients (20.4%). In the bivariate analysis, demographic and clinical variables were included, such as time since diagnosis, hypoglycemia history, A1c, GFR and treatment established. In the multivariate analysis, GFR 9% (OR 2.81; CI 1.05,7.51; p:0.04) and hypoglycemia history (OR 2.09; CI 1.02,4.32; p:0.04) were associated with HGV. Treatment with iDPP4 (OR 0.39; CI 0.19,0.82; p:0.01) and AGLP1 (OR 0.08; CI 0.01,0.68; p:0.02) was inversely associated with GV.
Conclusion: Clinical variables such as GFR 9% and a history of hypoglycemia are associated with a high GV. Our data suggest that the use of technology and treatments able to reduce glycemic variability could be useful in this population to reduce the risk of hypoglycemia and to improve glycemic control.Revista Internacional - Indexad
Nonadditive entropy and nonextensive statistical mechanics - Some central concepts and recent applications
We briefly review central concepts concerning nonextensive statistical
mechanics, based on the nonadditive entropy . Among others, we focus on
possible realizations of the -generalized Central Limit Theorem, including
at the edge of chaos of the logistic map, and for quasi-stationary states of
many-body long-range-interacting Hamiltonian systems.Comment: 15 pages, 9 figs., to appear in Journal of Physics: Conf.Series (IOP,
2010
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