1,445 research outputs found
A multi-protein receptor-ligand complex underlies combinatorial dendrite guidance choices in C. elegans.
Ligand receptor interactions instruct axon guidance during development. How dendrites are guided to specific targets is less understood. The C. elegans PVD sensory neuron innervates muscle-skin interface with its elaborate dendritic branches. Here, we found that LECT-2, the ortholog of leukocyte cell-derived chemotaxin-2 (LECT2), is secreted from the muscles and required for muscle innervation by PVD. Mosaic analyses showed that LECT-2 acted locally to guide the growth of terminal branches. Ectopic expression of LECT-2 from seam cells is sufficient to redirect the PVD dendrites onto seam cells. LECT-2 functions in a multi-protein receptor-ligand complex that also contains two transmembrane ligands on the skin, SAX-7/L1CAM and MNR-1, and the neuronal transmembrane receptor DMA-1. LECT-2 greatly enhances the binding between SAX-7, MNR-1 and DMA-1. The activation of DMA-1 strictly requires all three ligands, which establishes a combinatorial code to precisely target and pattern dendritic arbors
Orthogonality catastrophe and quantum speed limit for dynamical quantum phase transition
We investigate the orthogonality catastrophe and quantum speed limit in the
Creutz model for dynamical quantum phase transitions. We demonstrate that exact
zeros of the Loschmidt echo can exist in finite-size systems for specific
discrete values. We highlight the role of the zero-energy mode when analyzing
quench dynamics near the critical point. We also examine the behavior of the
time for the first exact zeros of the Loschmidt echo and the corresponding
quantum speed limit time as the system size increases. While the bound is not
tight, it can be attributed to the scaling properties of the band gap and
energy variance with respect to system size. As such, we establish a relation
between the orthogonality catastrophe and quantum speed limit by referencing
the full form of the Loschmidt echo. Significantly, we find the possibility of
using the quantum speed limit to detect the critical point of a static quantum
phase transition, along with a decrease in the amplitude of noise induced
quantum speed limit.Comment: 10 pages, 8 figure
Quantum and classical correlations in the one-dimensional XY model with Dzyaloshinskii-Moriya interaction
We study the effect of Dzyaloshinskii-Moriya (DM) interaction on pairwise
quantum discord, entanglement, and classical correlation in the anisotropic XY
spin-half chain. Analytical expressions for both quantum and classical
correlations are obtained from the spin-spin correlation functions. We show
that these pairwise quantities exhibit various behaviors in relation to the
relative strengths of the DM interaction, the anisotropy and the magnetic
intensity. We observe non-analyticities of the derivatives of both quantum and
classical correlations with respect to the magnetic intensity at the critical
point, with consideration of the DM interaction.Comment: 18pages, 6figure
Vehicle Communication using Secrecy Capacity
We address secure vehicle communication using secrecy capacity. In
particular, we research the relationship between secrecy capacity and various
types of parameters that determine secrecy capacity in the vehicular wireless
network. For example, we examine the relationship between vehicle speed and
secrecy capacity, the relationship between the response time and secrecy
capacity of an autonomous vehicle, and the relationship between transmission
power and secrecy capacity. In particular, the autonomous vehicle has set the
system modeling on the assumption that the speed of the vehicle is related to
the safety distance. We propose new vehicle communication to maintain a certain
level of secrecy capacity according to various parameters. As a result, we can
expect safer communication security of autonomous vehicles in 5G
communications.Comment: 17 Pages, 12 Figure
Revisiting the quantum Szilard engine with fully quantum considerations
By considering level shifting during the insertion process we revisit the
quantum Szilard engine (QSZE) with fully quantum consideration. We derive the
general expressions of the heat absorbed from thermal bath and the total work
done to the environment by the system in a cycle with two different cyclic
strategies. We find that only the quantum information contributes to the
absorbed heat, and the classical information acts like a feedback controller
and has no direct effect on the absorbed heat. This is the first demonstration
of the different effects of quantum information and classical information for
extracting heat from the bath in the QSZE. Moreover, when the well width
or the temperature of the bath
the QSZE reduces to the classical Szilard engine (CSZE), and the total work
satisfies the relation as obtained by
Sang Wook Kim et al. [Phys. Rev. Lett. 106, 070401 (2011)] for one particle
case.Comment: 17 pages, 3 figures, to be published in Annals of Physics(NY
Spectral self-adaptive absorber/emitter for harvesting energy from the sun and outer space
The sun (~6000 K) and outer space (~3 K) are the original heat source and
sink for human beings on Earth. The energy applications of absorbing solar
irradiation and harvesting the coldness of outer space for energy utilization
have attracted considerable interest from researchers. However, combining these
two functions in a static device for continuous energy harvesting is
unachievable due to the intrinsic infrared spectral conflict. In this study, we
developed spectral self-adaptive absorber/emitter (SSA/E) for daytime
photothermal and nighttime radiative sky cooling modes depending on the phase
transition of the vanadium dioxide coated layer. A 24-hour day-night test
showed that the fabricated SSA/E has continuous energy harvesting ability and
improved overall energy utilization performance, thus showing remarkable
potential in future energy applications.Comment: 15 pages, 4 figure
Deep-agriNet: a lightweight attention-based encoder-decoder framework for crop identification using multispectral images
The field of computer vision has shown great potential for the identification of crops at large scales based on multispectral images. However, the challenge in designing crop identification networks lies in striking a balance between accuracy and a lightweight framework. Furthermore, there is a lack of accurate recognition methods for non-large-scale crops. In this paper, we propose an improved encoder-decoder framework based on DeepLab v3+ to accurately identify crops with different planting patterns. The network employs ShuffleNet v2 as the backbone to extract features at multiple levels. The decoder module integrates a convolutional block attention mechanism that combines both channel and spatial attention mechanisms to fuse attention features across the channel and spatial dimensions. We establish two datasets, DS1 and DS2, where DS1 is obtained from areas with large-scale crop planting, and DS2 is obtained from areas with scattered crop planting. On DS1, the improved network achieves a mean intersection over union (mIoU) of 0.972, overall accuracy (OA) of 0.981, and recall of 0.980, indicating a significant improvement of 7.0%, 5.0%, and 5.7%, respectively, compared to the original DeepLab v3+. On DS2, the improved network improves the mIoU, OA, and recall by 5.4%, 3.9%, and 4.4%, respectively. Notably, the number of parameters and giga floating-point operations (GFLOPs) required by the proposed Deep-agriNet is significantly smaller than that of DeepLab v3+ and other classic networks. Our findings demonstrate that Deep-agriNet performs better in identifying crops with different planting scales, and can serve as an effective tool for crop identification in various regions and countries
Experimental Quantum Teleportation of a Two-Qubit Composite System
Quantum teleportation, a way to transfer the state of a quantum system from
one location to another, is central to quantum communication and plays an
important role in a number of quantum computation protocols. Previous
experimental demonstrations have been implemented with photonic or ionic
qubits. Very recently long-distance teleportation and open-destination
teleportation have also been realized. Until now, previous experiments have
only been able to teleport single qubits. However, since teleportation of
single qubits is insufficient for a large-scale realization of quantum
communication and computation2-5, teleportation of a composite system
containing two or more qubits has been seen as a long-standing goal in quantum
information science. Here, we present the experimental realization of quantum
teleportation of a two-qubit composite system. In the experiment, we develop
and exploit a six-photon interferometer to teleport an arbitrary polarization
state of two photons. The observed teleportation fidelities for different
initial states are all well beyond the state estimation limit of 0.40 for a
two-qubit system. Not only does our six-photon interferometer provide an
important step towards teleportation of a complex system, it will also enable
future experimental investigations on a number of fundamental quantum
communication and computation protocols such as multi-stage realization of
quantum-relay, fault-tolerant quantum computation, universal quantum
error-correction and one-way quantum computation.Comment: 16pages, 4 figure
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