The effects of local filtering processes on the structure and functioning of native plant communities in experimental urban habitats

Despite a growing literature-base devoted to documenting biodiversity patterns in cities, little is known about the processes that influence these patterns, and whether they are consistent over time. In particular, numerous studies have identified the capacity of cities to host a rich diversity of plant species. This trend, however, is driven primarily by introduced species, which comprise a large proportion of the urban species pool relative to natives. Using an experimental common garden study, we assessed the relative influence of local assembly processes (i.e., soil environmental filtering and competition from spontaneous urban species) on the taxonomic and functional diversity of native plant communities sampled over four seasons in 2016-2018. Taxonomic and functional diversity exhibited different responses to local processes, supporting the general conclusion that species- and trait-based measures of biodiversity offer distinct insights into community assembly dynamics. Additionally, we found that neither soil nor competition from spontaneous urban species influenced taxonomic or functional composition of native species. Functional composition, however, did shift strongly over time and was driven by community-weighted mean differences in both measured traits (maximum height, Hmax; specific leaf area, SLA; leaf chlorophyll a fluorescence, chl a) and the relative proportions of different functional groups (legumes, annual and biennial-perennial species, C4 grasses, and forbs). In contrast, taxonomic composition only diverged between early and late seasons. Overall, our results indicate that native species are not only capable of establishing and persisting in vacant urban habitats, they can functionally respond to local filtering pressures over time. This suggests that regional dispersal limitation may be a primary factor limiting native species in urban environments. Thus, future regreening and management plans should focus on enhancing the dispersal potential of native plant species in urban environments, in order to achieve set goals for increasing native species diversity and associated ecosystem services in cities.

Enhancing entanglement of two-qubit states from amplitude damping channel using single-qubit unitary operation and local filtering operation

We propose a scheme to enhance entanglement from amplitude damping or correlated amplitude damping decoherence. We show that entanglement sudden death time can be prolonged by the initial single-qubit operation combined with local filtering operation. For the amplitude damping channel case, we give the optimal single-qubit operation for arbitrary pure state [Formula: see text]. For the correlated amplitude damping channel case, we find that single-qubit operation on the initial state can not only enhance the final entanglement but also avoid entanglement sudden death. Compared to the previous schemes, the optimal operations and local filtering operations used in our scheme are independent with the decay parameters of the environment.

Optimal Demodulation Algorithm of Spatially Modulated Full-Polarization Imaging System

Spatially modulated full-polarization imaging systems can obtain full Stokes parameter information by single imaging, with strong characteristics of real-time execution and stability. Since all the polarization information is modulated into an interferogram, demodulation becomes an essential step. As the resolution of the obtained image continuously increases, the data to be calculated also increase. Therefore, a higher speed for the demodulation process is requisite. This article proposes a local filtering method and bypasses the frequency centralization method in the frequency domain to improve the speed of demodulation. The demodulation time of an interferogram of size 1024×1024 pixels was reduced from 3.027 473 s to 0.134 637 s, increasing the speed of demodulation by 97.72%. Meanwhile, the demodulation time of an interferogram of size 6144×6144 pixels was reduced from 444.329 92 s to 4.637 069 s, increasing the speed of demodulation by 98.75%.

Improving of steering and nonlocality via local filtering operation in Heisenberg XY model

In this work, we mainly study quantum steering and nonlocality of two-qubit Heisenberg [Formula: see text] spin-1/2 chain via local filtering operation. Our analytical results show that quantum steering and nonlocality can be affected by coupling constant [Formula: see text], temperature [Formula: see text], external magnetic field [Formula: see text] and anisotropy constant [Formula: see text]. Quantum steering and nonlocality would degrade with the increase of temperature [Formula: see text] and anisotropy constant [Formula: see text]. When [Formula: see text] is small, we can observe quantum steering and nonlocality increase with [Formula: see text]. When [Formula: see text] getting bigger, what we will see is that steering goes down first, then grows up. We can improve quantum steering and nonlocality via local filtering operation. We chose an appropriate parameter [Formula: see text], the steering and nonlocality can be improved when we fix three in those four parameters. There is a queer phenomenon in some situations that the range of one side for steering and nonlocality can extend greatly by losing them in another side. Therefore, our investigations might shed light on steering and nonlocality under the Heisenberg [Formula: see text] spin chain model and make a little step in the progress of quantum information.