4,538 research outputs found
Quantum Teleportation from a Propagating Photon to a Solid-State Spin Qubit
The realization of a quantum interface between a propagating photon used for
transmission of quantum information, and a stationary qubit used for storage
and manipulation, has long been an outstanding goal in quantum information
science. A method for implementing such an interface between dissimilar qubits
is quantum teleportation, which has attracted considerable interest not only as
a versatile quantum-state-transfer method but also as a quantum computational
primitive. Here, we experimentally demonstrate transfer of quantum information
carried by a photonic qubit to a quantum dot spin qubit using quantum
teleportation. In our experiment, a single photon in a superposition state of
two colors -- a photonic qubit is generated using selective resonant excitation
of a neutral quantum dot. We achieve an unprecedented degree of
indistinguishability of single photons from different quantum dots by using
local electric and magnetic field control. To teleport a photonic qubit, we
generate an entangled spin-photon state in a second quantum dot located 5
meters away from the first and interfere the photons from the two dots in a
Hong-Ou-Mandel set-up. A coincidence detection at the output of the
interferometer heralds successful teleportation, which we verify by measuring
the resulting spin state after its coherence time is prolonged by an optical
spin-echo pulse sequence. The demonstration of successful inter-conversion of
photonic and semiconductor spin qubits constitute a major step towards the
realization of on-chip quantum networks based on semiconductor nano-structures.Comment: 12 pages, 3 figures, Comments welcom
Hypothalamic AMPK-ER Stress-JNK1 Axis Mediates the Central Actions of Thyroid Hormones on Energy Balance
Thyroid hormones (THs) act in the brain to modulate energy balance. We show that central triiodothyronine (T3) regulates de novo lipogenesis in liver and lipid oxidation in brown adipose tissue (BAT) through the parasympathetic (PSNS) and sympathetic nervous system (SNS), respectively. Central T3 promotes hepatic lipogenesis with parallel stimulation of the thermogenic program in BAT. The action of T3 depends on AMP-activated protein kinase (AMPK)-induced regulation of two signaling pathways in the ventromedial nucleus of the hypothalamus (VMH): decreased ceramide-induced endoplasmic reticulum (ER) stress, which promotes BAT thermogenesis, and increased c-Jun N-terminal kinase (JNK) activation, which controls hepatic lipid metabolism. Of note, ablation of AMPKalpha1 in steroidogenic factor 1 (SF1) neurons of the VMH fully recapitulated the effect of central T3, pointing to this population in mediating the effect of central THs on metabolism. Overall, these findings uncover the underlying pathways through which central T3 modulates peripheral metabolism
Adherence to 24-Hour Movement Guidelines among Spanish Adolescents: Differences between Boys and Girls
Background: The 24-Hour Movement Guidelines for adolescents recommend >= 60 min/day of moderate-to-vigorous physical activity (PA), <= 2 h/day of screen time, and 8-10 h/day of sleep. Since little information is available on the 24-Hour Movement Guidelines in Spanish adolescents, this study aims to estimate the proportion of Spanish adolescents meeting individual and combinations of these 24-Hour Movement Guidelines. Moreover, another aim of this study is to examine gender differences in compliance with 24-Hour Movement Guidelines. Methods: A final sample of 1465 Spanish adolescents (44.50% girls; 13.08 +/- 0.86) participated in this cross-sectional study. The 24-Hour Movement Guidelines were measured during weekdays and the weekend days by self-reported questionnaires. Results: Although most adolescents met sleep duration guidelines (81.3%), only 38% and 15.8% met physical activity and screen time guidelines, respectively. Only 5.4% of these adolescents met all three 24-Hour Movement Guidelines, whereas 10.2% of this sample did not meet any of these guidelines. Although boys reported greater compliance with physical activity recommendations and girls with screen time recommendations, no significant gender differences were found in the compliance of all three 24-Hour Movement Guidelines. Conclusion: Given that 94.4% of Spanish adolescents did not meet 24-Hour Movement Guidelines, promoting all these three movement behaviours in both boys and girls is an urgent public health priority
GPS-aided Visual Wheel Odometry
This paper introduces a novel GPS-aided visual-wheel odometry (GPS-VWO) for
ground robots. The state estimation algorithm tightly fuses visual, wheeled
encoder and GPS measurements in the way of Multi-State Constraint Kalman Filter
(MSCKF). To avoid accumulating calibration errors over time, the proposed
algorithm calculates the extrinsic rotation parameter between the GPS global
coordinate frame and the VWO reference frame online as part of the estimation
process. The convergence of this extrinsic parameter is guaranteed by the
observability analysis and verified by using real-world visual and wheel
encoder measurements as well as simulated GPS measurements. Moreover, a novel
theoretical finding is presented that the variance of unobservable state could
converge to zero for specific Kalman filter system. We evaluate the proposed
system extensively in large-scale urban driving scenarios. The results
demonstrate that better accuracy than GPS is achieved through the fusion of GPS
and VWO. The comparison between extrinsic parameter calibration and
non-calibration shows significant improvement in localization accuracy thanks
to the online calibration.Comment: Accepted by IEEE ITSC 202
Synthesis and evaluation of biphenyl derivatives as potential downregulators of VEGF protein secretion and telomerase-related gene expressions
A group of 47 biphenyl functionalized compounds, prepared by means of Suzuki couplings, has been
investigated for their cytotoxicity on two tumoral cell lines (HT-29 and MCF-7) and one non tumoral cell
line (HEK-293). 29 selected compounds have been investigated for their ability to inhibit the production
of the vascular endothelial growth factor (VEGF). Subsequently, the capacity of the compounds to downregulate
the expression of the VEGF, h-TERT and c-Myc genes, the two latter involved in the control of the
activation of telomerase, has also been determined.Financial support has been granted to M.C. by the Ministerio
de Economía y Competitividad of Spain (project CTQ2014-
52949-P), by the Consellería d´Empresa, Universitat i Ciencia de
la Generalitat Valenciana (projects PROMETEO/2013/027 and
ACOMP/2014/ 274) and by the University Jaume I (project PI-
1B2011-37). M. S.-P. thanks the University Jaume I for a
predoctoral fellowship
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