6,583 research outputs found
Quantum Hysteresis in Coupled Light-Matter Systems
We investigate the non-equilibrium quantum dynamics of a canonical
light-matter system, namely the Dicke model, when the light-matter interaction
is ramped up and down through a cycle across the quantum phase transition. Our
calculations reveal a rich set of dynamical behaviors determined by the cycle
times, ranging from the slow, near adiabatic regime through to the fast, sudden
quench regime. As the cycle time decreases, we uncover a crossover from an
oscillatory exchange of quantum information between light and matter that
approaches a reversible adiabatic process, to a dispersive regime that
generates large values of light-matter entanglement. The phenomena uncovered in
this work have implications in quantum control, quantum interferometry, as well
as in quantum information theory.Comment: 9 pages and 4 figure
Quantum Phase Transitions detected by a local probe using Time Correlations and Violations of Leggett-Garg Inequalities
In the present paper we introduce a way of identifying quantum phase
transitions of many-body systems by means of local time correlations and
Leggett-Garg inequalities. This procedure allows to experimentally determine
the quantum critical points not only of finite-order transitions but also those
of infinite order, as the Kosterlitz-Thouless transition that is not always
easy to detect with current methods. By means of simple analytical arguments
for a general spin- Hamiltonian, and matrix product simulations of
one-dimensional and anisotropic models, we argue that
finite-order quantum phase transitions can be determined by singularities of
the time correlations or their derivatives at criticality. The same features
are exhibited by corresponding Leggett-Garg functions, which noticeably
indicate violation of the Leggett-Garg inequalities for early times and all the
Hamiltonian parameters considered. In addition, we find that the infinite-order
transition of the model at the isotropic point can be revealed by the
maximal violation of the Leggett-Garg inequalities. We thus show that quantum
phase transitions can be identified by purely local measurements, and that
many-body systems constitute important candidates to observe experimentally the
violation of Leggett-Garg inequalities.Comment: Minor changes, 11 pages, 11 figures. Final version published in Phys.
Rev.
An economic valuation of the horse production and utilization in Andalucia (Spain)
The Tourism and Sport Department of the Andalusian Government agreed to the University of Córdoba (Spain) an economic analysis of all the equestrian activities developed in Andalucía in 2002. It was sought to establish some axes of strategic behavior for the sector. With this idea, the general objectives of the work are planned: to analyze the total production generated by each activity developed in Andalucía in 2002, in which the horse is the main element of operation. The work begins with the definition of each activity and the executioner establishments. Once activites are defined, the economic valuation is realized by analyzing their costs of organization and participation. These results are aggregated and ordered in input-output tables for economic valuation of the total production generated by the sector in Andalucía. The results show that, in 2002, this sector produced 478 million of euros of which 320 millions proceeded from productive and selection activities of horses; 50 millions from sport activities; 31.3 millions from activities of leisure; 15 millions of recreational activities with participation and 26.4 millions were specific from the World Equestrian Games.La Consejería de Turismo y Deportes de la Junta de Andalucía convino con la Universidad de Córdoba un análisis de todas las actividades relacionadas con el caballo desarrolladas en Andalucía en el 2002. Con este fin se planean los objetivos generales del trabajo: analizar la producción total generada por cada una de las actividades desarrolladas en Andalucía en el 2002, en las que el caballo es el elemento esencial para su ejecución. El trabajo comienza con la definición de cada una de las actividades y los establecimientos operadores de aquellas. La valoración económica se realiza a partir del análisis de sus costes de organización y participación. Estos resultados se agregan y ordenan en tablas input-output para obtener la valoración económica de la producción total generada por el sector del caballo en Andalucía. Los resultados demuestran que, en 2002, este sector aportó a la producción bruta andaluza 478 millones de euros de los cuales 320 fueron de actividades productivas y selectivas de ganado; 50 de actividades deportivas; 31,3 de actividades de ocio contemplativo; 15 de actividades recreativas participativas y 26,4 específicos del encuentro de Jerez 2002
Dynamics of Entanglement and the Schmidt Gap in a Driven Light-Matter System
The ability to modify light-matter coupling in time (e.g. using external
pulses) opens up the exciting possibility of generating and probing new aspects
of quantum correlations in many-body light-matter systems. Here we study the
impact of such a pulsed coupling on the light-matter entanglement in the Dicke
model as well as the respective subsystem quantum dynamics. Our dynamical
many-body analysis exploits the natural partition between the radiation and
matter degrees of freedom, allowing us to explore time-dependent
intra-subsystem quantum correlations by means of squeezing parameters, and the
inter-subsystem Schmidt gap for different pulse duration (i.e. ramping
velocity) regimes -- from the near adiabatic to the sudden quench limits. Our
results reveal that both types of quantities indicate the emergence of the
superradiant phase when crossing the quantum critical point. In addition, at
the end of the pulse light and matter remain entangled even though they become
uncoupled, which could be exploited to generate entangled states in
non-interacting systems.Comment: 15 pages, 4 figures, Accepted for publication in Journal of Physics
B, special issue Correlations in light-matter interaction
Museum visitors’ heterogeneity and experience processing
This research examines the relationships between affective and cognitive antecedents and consequences of satisfaction under a market heterogeneity approach. It includes co-creation of preparatory activities. The sample consisted of 276 museum visitors in London. Two analysis have been conducted: structural equation model and latent class path analysis. The paper contributes to the development of a theoretical framework for further understanding of service experience in which co-creation plays an important role. Two segments were identified: 1) emotional (with lower degree of co-creation, equally distributed by age and nationality); 2) rational (higher degree of co-creation, younger and domestic visitors). Our research shows significant differences between the two segments regarding variables such as satisfaction, loyalty, service experience, emotion, positive disconfirmation and willingness to pay more
Horizontal target strength-size conversion equations for sea bass and gilt-head bream
[EN] Horizontal hydroacoustics is a technique of remote fish detection that has proved to efficiently determine fish density and biomass in shallow or superficial waters. This non-intrusive technique could render better results than those obtained by conventional sampling when monitoring shallow waters. To apply this technique, we need equations that relate the amount of sound returned by fish, known as target strength (TS in dB), with their length (mm) or weight (g). This study presents horizontal conversion equations for the species gilt-head bream (Sparus aurata) and sea bass (Dicentrarchus labrax), two of the most important species bred in aquaculture. Moreover, this study presents a new formula to calculate a mixed equation adjusted to the percentage of distribution of those species in case of mixed populations. The results in this research have been obtained by applying a simple setup that allows for high-quality acoustic data. These new equations will enable the application of this technique in order to estimate these species' density and biomass in shallow aquatic systems such as aquaculture ponds with semi-intensive production densities.This study's authors would like to thank the Superintendent of Economy and Knowledge (Andalusian Government) for the funding provided as part of the project (PI_57052) developed in collaboration with CTAQUA. We would like to thank the researchers Carlos Orduna Marin and Juan Ramon Cid Quintero for their selfless work to obtain the field data and to the company PIMSA for generously allowing us to use their facilities and fish. We would also like to thank the veterinarian JR Rodriguez for being kind enough to perform X-rays on the studied fish and Cristina Ocana for her careful proofreading of the English text.Rodríguez-Sánchez, V.; Rodríguez-Ruiz, A.; Pérez Arjona, I.; Encina-Encina, L. (2018). Horizontal target strength-size conversion equations for sea bass and gilt-head bream. Aquaculture. 490:178-184. https://doi.org/10.1016/j.aquaculture.2018.02.034S17818449
1–42 b -Amyloid peptide requires PDK1/nPKC/Rac 1 pathway to induce neuronal death
1–42
b
-Amyloid peptide requires PDK1/nPKC/Rac 1
pathway to induce neuronal death
L Manterola
1,12
, M Hernando-Rodr
ı
́
guez
2,12
, A Ruiz
3,4
, A Apraiz
5
, O Arrizabalaga
5
, L Vello
́
n
6
, E Alberdi
3,4
, F Cavaliere
3,4
, HM Lacerda
7
,
S Jimenez
8,9
, LA Parada
10
, C Matute
3,4
and JL Zugaza
4,5,11
1–42
b
-Amyloid (A
b
1–42
) peptide is a key molecule involved in the development of Alzheimer’s disease. Some of its effects are
manifested at the neuronal morphological level. These morphological changes involve loss of neurites due to cytoskeleton
alterations. However, the mechanism of A
b
1–42
peptide activation of the neurodegenerative program is still poorly understood.
Here, A
b
1–42
peptide-induced transduction of cellular death signals through the phosphatidylinositol 3-kinase (PI3K)/
phosphoinositol-dependent kinase (PDK)/novel protein kinase C (nPKC)/Rac 1 axis is described. Furthermore, pharmacological
inhibition of PDK1 and nPKC activities blocks Rac 1 activation and neuronal cell death. Our results provide insights into an
unsuspected connection between PDK1, nPKCs and Rac 1 in the same signal-transduction pathway and points out nPKCs and
Rac 1 as potential therapeutic targets to block the toxic effects of A
b
1–42
peptide in neurons
Thermal study of a transport container
A thermal study of a container for international transport has been carried out in order to determine the temperature distributions. Several experimental conditions such as cooling modes, the onset of defrosting, the existence of cargo inside the container and two varying set points have been evaluated. It was observed that the difference between the temperature inside the container and the set point raised up to 30% of ambient temperature. Moreover, it was observed that the modulated cooling allowed to obtain a more homogeneous refrigeration. However, temperature differences up to 8 °C were observed under on–off control cooling
Performance of ZigBee-based wireless sensor nodes for real-time monitoring of fruits logistics
Progress in fruit logistics requires an increasing number of measurements to be performed in refrigerated chambers and during transport. Wireless sensor networks (WSN) are a promising solution in this field. This paper explores the potential of wireless sensor technology for monitoring fruit storage and transport conditions. It focuses in particular on ZigBee technology with special regard to two different commercial modules (Xbow and Xbee). The main contributions of the paper relate to the analysis of battery life under cooling conditions and the evaluation of the reliability of communications and measurements. Psychrometric equations were used for quick assessment of changes in the absolute water content of air, allowing estimation of future water loss, and detection of condensation on the product
Correlation Between Endoglin and Malignant Phenotype in Human Melanoma Cells: Analysis of hsa-mir-214 and hsa-mir-370 in Cells and Their Extracellular Vesicles.
Endoglin (CD105) is an auxiliary receptor of transforming growth factor (TGF)-β family members that is expressed in human melanomas. It is heterogeneously expressed by primary and metastatic melanoma cells, and endoglin targeting as a therapeutic strategy for melanoma tumors is currently been explored. However, its involvement in tumor development and malignancy is not fully understood. Here, we find that endoglin expression correlates with malignancy of primary melanomas and cultured melanoma cell lines. Next, we have analyzed the effect of ectopic endoglin expression on two miRNAs (hsa-mir-214 and hsa-mir-370), both involved in melanoma tumor progression and endoglin regulation. We show that compared with control cells, overexpression of endoglin in the WM-164 melanoma cell line induces; (i) a significant increase of hsa-mir-214 levels in small extracellular vesicles (EVs) as well as an increased trend in cells; and (ii) significantly lower levels of hsa-mir-370 in the EVs fractions, whereas no significant differences were found in cells. As hsa-mir-214 and hsa-mir-370 are not just involved in melanoma tumor progression, but they can also target endoglin-expressing endothelial cells in the tumor vasculature, these results suggest a complex and differential regulatory mechanism involving the intracellular and extracellular signaling of hsa-mir-214 and hsa-mir-370 in melanoma development and progression.S
- …