SRB Measures for A Class of Partially Hyperbolic Attractors in Hilbert spaces

In this paper, we study the existence of SRB measures and their properties for infinite dimensional dynamical systems in a Hilbert space. We show several results including (i) if the system has a partially hyperbolic attractor with nontrivial finite dimensional unstable directions, then it has at least one SRB measure; (ii) if the attractor is uniformly hyperbolic and the system is topological mixing and the splitting is H\"older continuous, then there exists a unique SRB measure which is mixing; (iii) if the attractor is uniformly hyperbolic and the system is non-wondering and and the splitting is H\"older continuous, then there exists at most finitely many SRB measures; (iv) for a given hyperbolic measure, there exist at most countably many ergodic components whose basin contains an observable set

Existence of SRB Measures for A Class of Partially Hyperbolic Attractors in Banach spaces

In this paper, we study the existence of SRB measures for infinite dimensional dynamical systems in a Banach space. We show that if the system has a partially hyperbolic attractor with nontrivial finite dimensional unstable directions, then it has an SRB measure.Comment: arXiv admin note: text overlap with arXiv:1508.0330

Do high housing prices crowd out young professionals?—Micro-evidence from China

Motivated by the growing trend of young professionals flowing out of high-profile cities in China, this study examines whether high housing prices have a crowding-out effect on young professionals across 235 Chinese cities. Using a conditional logit model with multiple control variables related to the economy, the social environment, and city location, the results showed an inverted Ushaped relationship between a city’s house prices and young professionals’ potential migration into the city. We also performed a series of robustness checks and categorised the sample by gender, academic qualification, and marital status. The results indicated the same inverted U-shaped relationship, but with different extreme points for house prices across the sub-samples. The findings offer suggestions for Chinese local governments to attract young professionals by regulating housing prices in cities where prices surpass the extreme point

Bacteria photosensitized by intracellular gold nanoclusters for solar fuel production.

The demand for renewable and sustainable fuel has prompted the rapid development of advanced nanotechnologies to effectively harness solar power. The construction of photosynthetic biohybrid systems (PBSs) aims to link preassembled biosynthetic pathways with inorganic light absorbers. This strategy inherits both the high light-harvesting efficiency of solid-state semiconductors and the superior catalytic performance of whole-cell microorganisms. Here, we introduce an intracellular, biocompatible light absorber, in the form of gold nanoclusters (AuNCs), to circumvent the sluggish kinetics of electron transfer for existing PBSs. Translocation of these AuNCs into non-photosynthetic bacteria enables photosynthesis of acetic acid from CO2. The AuNCs also serve as inhibitors of reactive oxygen species (ROS) to maintain high bacterium viability. With the dual advantages of light absorption and biocompatibility, this new generation of PBS can efficiently harvest sunlight and transfer photogenerated electrons to cellular metabolism, realizing CO2 fixation continuously over several days

Giant Light-Emission Enhancement in Lead Halide Perovskites by Surface Oxygen Passivation.

Surface condition plays an important role in the optical performance of semiconductor materials. As new types of semiconductors, the emerging metal-halide perovskites are promising for next-generation optoelectronic devices. We discover significantly improved light-emission efficiencies in lead halide perovskites due to surface oxygen passivation. The enhancement manifests close to 3 orders of magnitude as the perovskite dimensions decrease to the nanoscale, improving external quantum efficiencies from <0.02% to over 12%. Along with about a 4-fold increase in spontaneous carrier recombination lifetimes, we show that oxygen exposure enhances light emission by reducing the nonradiative recombination channel. Supported by X-ray surface characterization and theoretical modeling, we propose that excess lead atoms on the perovskite surface create deep-level trap states that can be passivated by oxygen adsorption

Structural and spectral dynamics of single-crystalline Ruddlesden-Popper phase halide perovskite blue light-emitting diodes.

Achieving perovskite-based high-color purity blue-emitting light-emitting diodes (LEDs) is still challenging. Here, we report successful synthesis of a series of blue-emissive two-dimensional Ruddlesden-Popper phase single crystals and their high-color purity blue-emitting LED demonstrations. Although this approach successfully achieves a series of bandgap emissions based on the different layer thicknesses, it still suffers from a conventional temperature-induced device degradation mechanism during high-voltage operations. To understand the underlying mechanism, we further elucidate temperature-induced device degradation by investigating the crystal structural and spectral evolution dynamics via in situ temperature-dependent single-crystal x-ray diffraction, photoluminescence (PL) characterization, and density functional theory calculation. The PL peak becomes asymmetrically broadened with a marked intensity decay, as temperature increases owing to [PbBr6]4- octahedra tilting and the organic chain disordering, which results in bandgap decrease. This study indicates that careful heat management under LED operation is a key factor to maintain the sharp and intense emission

Botulinum toxin type A for hand tremor: a meta-analysis of randomised controlled trials

Background. Tremor is one of the most common movement disorders. It does not usually respond to first-line drug treatments (e.g. propranolol, primidone, anticholinergics, gabapentin and clonazepam) due to side effects and frequent dose limitations. Botulinum toxin type A (BoNT-A) has been widely used to treat tremor, but its efficacy and safety are uncertain.Aims. To evaluate the efficacy and safety of BoNT-A in the treatment of hand tremor.Methods. We searched the MEDLINE, EMBASE, PsycINFO and Cochrane Library databases for relevant randomised controlled trials of the effects of BoNT-A injections on tremors, up to 20 February 2020. A meta-analysis of comparative effects was performed using R studio software, and publication bias was examined using Egger’s test.Results. Six studies examining a total of 245 participants with tremor were included in the meta-analysis. The primary outcome of meta-analysis showed no difference in clinical tremor scale scores between the BoNT-A group versus the placebo group (standardised mean difference (SMD): -0.42, 95% confidence interval (CI): -1.94 to 1.10; I2 = 96%). For clinical tremor scale scores, subgroup analyses suggested that the BoNT-A group may differ in terms of multiple sclerosis (MS) related tremor (SMD: -1.10; 95% CI: -2.17 to -0.04; I2 = 79%) compared to a placebo, but the difference did not exist in the outcome of essential tremor (ET) or hand tremor (MD: -1.31; 95% CI: -3.39; 1.31; I2 = 97%). Grip strength (MD: -1.25, 95% CI: -5.99 to 3.50, I2 = 97%) was slightly lower in the BoNT-A group, but the difference was not significant. The incidence of adverse events (AEs), including hand weakness (RR: 2.96, 95% CI: 1.40 to 6.24, I2 = 37%), was significantly greater in the BoNT-A group than in the placebo group. Two studies were assessed as having an overall low risk of bias.Conclusions. Our study confirms that BoNT-A injections are unlikely to have an impact on patients with hand tremors. However, subgroup analysis suggested that BoNT-A injections could have possible benefits in MS-related tremor. While moderate to severe hand weakness AEs often limits their use in clinical practice, additional well-designed double-blind, placebo-controlled trials are needed to provide more robust conclusions