Evolutionary responses of a dominant plant along a successional gradient in a salt-marsh system

The ecological responses of plant populations along a successional gradient have been intensively examined; however, the evolutionary responses received much less attention. Here, I explored genetic changes of key phenotypic traits of a dominant clonal plant (Elytrigia atherica) along a saltmarsh successional gradient by collecting samples along the successional gradient in the high and low marsh and growing them in a common environment (greenhouse). Additionally, to explore whether changes in traits are driven by abiotic (e.g. clay thickness) and biotic (e.g. grazing intensity) variables along the successional gradient, I measured these two variables in the field. I found that clay thickness (a proxy of total nitrogen) increased along the successional gradient both in the high and low marsh; grazing intensity from hares (the most important herbivores) decreased along the successional gradient in the high marsh but did not change in the low marsh. Meanwhile, I found that growth in number of leaves and ramets decreased, while rhizome length increased, along the successional gradient for E. atherica collected from the high marsh. Opposite trends were found for E. atherica collected from the low marsh. Results suggest that, in the high marsh, herbivores may overrule nutrients to drive trait changes. That is, at the early successional stages, E. atherica had higher growth in number of leaves and ramets to compensate for high-intensity grazing. In the low marsh, nutrients may be the dominant driver for trait changes. That is, at the late successional stages, E. atherica had higher growth in number of leaves and ramets but shorter rhizomes to maximize its expansion under the favorable conditions (higher nutrient availability). Results suggest that ecologically important abiotic and biotic variables such as nutrients and herbivores may also have a substantial evolutionary impact on plant populations

Long-term effects of large and small herbivores on plant diversity in a salt-marsh system

It is well known that herbivores impact plant communities globally. However, the decade-long effects of herbivores on plant communities remain unclear, due to limited long-term experiments. Using 46-year large herbivore exclosures and 22-year small herbivore exclosures in the salt marsh of the island of Schiermonnikoog, I evaluated the long-term effects of large (cattle) and small herbivores (hares and geese) on plant diversity. I found that long-term management is needed for conserving biodiversity. In addition, using low to moderate densities of large domestic herbivores to conserve plant diversity is sustainable for at least 46 years. However, the effects of large herbivores on biodiversity were more attributed to the non-trophic effects (e.g. trampling, and deposition of urine and dung), particular in the long-term (23 years after). Small wild herbivores (hares and geese) can also slow down plant species decline (for at least 22 years) but only at the early successional stage where their abundance was high. A diverse herbivore community (hares and geese relative to hares alone) had a more positive control of plant communities. On top of that, these ecologically important small herbivores may also have substantial evolutionary effects such as modify local-scale spatial genetic structure of a dominant plant species. Results emphasize the need for the conservation and re-introduction of herbivores, domestic or wild, to sustain long-term grassland plant diversity

Fundamental Limits of Intelligent Reflecting Surface Aided Multiuser Broadcast Channel

Intelligent reflecting surface (IRS) has recently received significant attention in wireless networks owing to its ability to smartly control the wireless propagation through passive reflection. Although prior works have employed the IRS to enhance the system performance under various setups, the fundamental capacity limits of an IRS aided multi-antenna multi-user system have not yet been characterized. Motivated by this, we investigate an IRS aided multiple-input single-output (MISO) broadcast channel by considering the capacity-achieving dirty paper coding (DPC) scheme and dynamic beamforming configurations. We first propose a bisection based framework to characterize its capacity region by optimally solving the sum-rate maximization problem under a set of rate constraints, which is also applicable to characterize the achievable rate region with the zero-forcing (ZF) scheme. Interestingly, it is rigorously proved that dynamic beamforming is able to enlarge the achievable rate region of ZF if the IRS phase-shifts cannot achieve fully orthogonal channels, whereas the attained gains become marginal due to the reduction of the channel correlations induced by smartly adjusting the IRS phase-shifts. The result implies that employing the IRS is able to reduce the demand for implementing dynamic beamforming. Finally, we analytically prove that the sum-rate achieved by the IRS aided ZF is capable of approaching that of the IRS aided DPC with a sufficiently large IRS in practice. Simulation results shed light on the impact of the IRS on transceiver designs and validate our theoretical findings, which provide useful guidelines to practical systems by indicating that replacing sophisticated schemes with easy-implementation schemes would only result in slight performance loss

Market integration in China

Over the last three decades, China's product, labor, and capital markets have become gradually more integrated within its borders, although integration has been significantly slower for capital markets. There remains a significant urban-rural divide, and Chinese cities tend to be under-sized by international standards. China has also integrated globally, initially through the Special Economic Zones on the coast as launching grounds to connect with world markets, and subsequently through the accession to the World Trade Organization. For future policy considerations, this paper argues that its economic production needs to be spatially concentrated, and its social services need to be spread out to the interior to ensure harmonious development and domestic integration (through inclusive rural-urban transformations and effective territorial development).Economic Theory&Research,Banks&Banking Reform,Debt Markets,Emerging Markets,Access to Finance

Transmissive RIS Transmitter Enabled Spatial Modulation for MIMO Systems

In this paper, we propose a novel transmissive reconfigurable intelligent surface (TRIS) transmitter-enabled spatial modulation (SM) multiple-input multiple-output (MIMO) system. In the transmission phase, a column-wise activation strategy is implemented for the TRIS panel, where the specific column elements are activated per time slot. Concurrently, the receiver employs the maximum likelihood detection technique. Based on this, for the transmit signals, we derive the closed-form expressions for the upper bounds of the average bit error probability (ABEP) of the proposed scheme from different perspectives, employing both vector-based and element-based approaches. Furthermore, we provide the asymptotic closed-form expressions for the ABEP of the TRIS-SM scheme, as well as the diversity gain. To improve the performance of the proposed TRIS-SM system, we optimize ABEP with a fixed data rate. Additionally, we provide lower bounds to simplify the computational complexity of improved TRIS-SM scheme. The Monte Carlo simulation method is used to validate the theoretical derivations exhaustively. The results demonstrate that the proposed TRIS-SM scheme can achieve better ABEP performance compared to the conventional SM scheme. Furthermore, the improved TRIS-SM scheme outperforms the TRIS-SM scheme in terms of reliability