Design Optimization of Linear Precoders for Complex Vector Gaussian Channelswith Finite Alphabet Inputs

We study the design optimization of linear precoders that maximize the mutual information in complex-valued vector Gaussian channels under finite alphabet inputs. It is well known that mutual information of a vector channel with discrete constellation source is a highly nonlinear and nonconcave function of the linear precoder matrix G, thereby complicating the precoder design optimization. in this paper, we show that the mutual information is a concave function of W = GhHhHG, where H is the complex-valued channel matrix and superscript h represents conjugate transpose. We further propose an iterative algorithm for solving the globally optimal linear precoder G. Illustrative results show that the proposed iterative algorithm is very robust and efficient for global convergence. © 2011 IEEE

Reciprocal regulation of glycine-rich RNA-binding proteins via an interlocked feedback loop coupling alternative splicing to nonsense-mediated decay in Arabidopsis

The Arabidopsis RNA-binding protein AtGRP8 undergoes negative autoregulation at the post-transcriptional level. An elevated AtGRP8 protein level promotes the use of a cryptic 5′ splice site to generate an alternatively spliced transcript, as_AtGRP8, retaining the 5′ half of the intron with a premature termination codon. In mutants defective in nonsense-mediated decay (NMD) abundance of as_AtGRP8 but not its pre-mRNA is elevated, indicating that as_AtGRP8 is a direct NMD target, thus limiting the production of functional AtGRP8 protein. In addition to its own pre-mRNA, AtGRP8 negatively regulates the AtGRP7 transcript through promoting the formation of the equivalent alternatively spliced as_AtGRP7 transcript, leading to a decrease in AtGRP7 abundance. Recombinant AtGRP8 binds to its own and the AtGRP7 pre-mRNA, suggesting that this interaction is relevant for the splicing decision in vivo. AtGRP7 itself is part of a negative autoregulatory circuit that influences circadian oscillations of its own and the AtGRP8 transcript through alternative splicing linked to NMD. Thus, we identify an interlocked feedback loop through which two RNA-binding proteins autoregulate and reciprocally crossregulate by coupling unproductive splicing to NMD. A high degree of evolutionary sequence conservation in the introns retained in as_AtGRP8 or as_AtGRP7 points to an important function of these sequences

Single cell atlas for 11 non-model mammals, reptiles and birds.

The availability of viral entry factors is a prerequisite for the cross-species transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Large-scale single-cell screening of animal cells could reveal the expression patterns of viral entry genes in different hosts. However, such exploration for SARS-CoV-2 remains limited. Here, we perform single-nucleus RNA sequencing for 11 non-model species, including pets (cat, dog, hamster, and lizard), livestock (goat and rabbit), poultry (duck and pigeon), and wildlife (pangolin, tiger, and deer), and investigated the co-expression of ACE2 and TMPRSS2. Furthermore, cross-species analysis of the lung cell atlas of the studied mammals, reptiles, and birds reveals core developmental programs, critical connectomes, and conserved regulatory circuits among these evolutionarily distant species. Overall, our work provides a compendium of gene expression profiles for non-model animals, which could be employed to identify potential SARS-CoV-2 target cells and putative zoonotic reservoirs

Bending performance of recycled concrete one-way slabs after pre-soaking in a nano-SiO₂ solution and the subsequent carbonation

This study employed a method of strengthening recycled coarse aggregates through pre-soaking in a nano-SiO₂ solution followed by carbonation. The impact of these modified recycled coarse aggregates on the bending performance of one-way recycled concrete slabs was investigated. Five specimens were fabricated and tested, including one one-way natural concrete slab, two one-way recycled concrete slabs, and two one-way slabs with modified recycled coarse aggregate. As a result, the failure of the recycled concrete slabs occurred due to the yield of the longitudinal reinforcement and the maximum crack width at the bottom of the slab, which reached the limit. The maximum load-bearing capacity of the slabs decreased with an increase in the replacement rate of the recycled coarse aggregates. However, one-way slabs containing modified recycled coarse aggregate showed an improvement in the ultimate bearing capacity, with increases of 3.5% and 5.1% when the proportion of modified recycled coarse aggregate used as a replacement was augmented from 50% to 100%. Finally, based on a reasonable material constitutive relationship, a finite element model of one-way slabs under four-point bending was established. The model simulated the loading process of the five types of slabs, further analysing the impact of modified recycled coarse aggregate on the bending performance of the slabs. Moreover, based on the experimental and finite element simulation results, several suggestions were put forward, providing references for similar studies

THE EFFECTS OF POLYALUMINIUM CHLORIDE (PAC) SLAG ON THE PROPERTIES OF RECYCLED CONCRETE

In this paper, recycled concrete aggregates and PAC slag were used to prepare concrete. X-ray fluorescence (XRF), X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to analyse the micro-properties of the PAC and the concrete. Furthermore, the effects of the activators on the water absorption, compressive strength and frost resistance of the concrete were studied. The results showed that the effects of the activators on the water absorption were not obvious, but they could improve the activity of the PAC slag, thus, the hydration products in the mortar significantly increased and the micro-structure of the mortar became denser. Furthermore, the compressive strength of the concrete at 28 days increased by 26.5% when the activator was mixed with 3% water glass and 3% sodium sulfate. Moreover, the activators could improve the frost resistance of the concrete. However, when the activators were added in the concrete together, negative effects were found on the frost resistance of the concrete, with a mass loss of 20%

Fracture Energy Analysis of Concrete considering the Boundary Effect of Single-Edge Notched Beams

The method of determining concrete fracture energy recommended by RILEM has an obvious size effect, so determining fracture energy that is unaffected by size of the test specimen is difficult. In this study, 60 high-strength concrete single-edge notched beams (SENBs) of different sizes, crack length-to-depth ratios, and span-to-depth ratios were subjected to the three-point loading test as recommended by RILEM. Then, the influences of the boundary effect on the fracture energy were identified. Based on the SENB boundary effect model, a piecewise function of the interrelationships between the experimental test fracture energy Gf, the local fracture energy gf, and the fracture energy unaffected by specimen size GF was established. The applicability of the boundary effect model was verified using the test results from this study and from the previously published research. The results show that the local fracture energy distribution in the boundary influence region was nonuniform. The smaller the local fracture energy was, the closer it was to the rear boundary of the specimen. The influence length al∗ of the boundary increased with the increasing specimen size. Based on the bilinear distribution model of the local fracture energy gf, the fracture energy unaffected by beam size GF can be obtained according to the fracture energy Gf measured for laboratory-scale small-sized SENB specimens. Furthermore, the model predictions are in good agreement with experimental observations