Estimation and Testing of Varying Coefficients in Quantile Regression

<p>In this article, we establish a novel connection between the null hypothesis <i>H</i>₀ on the coefficients and a rank-reducible form of the varying coefficient model in quantile regression. We use <i>B</i>-splines to approximate the varying coefficients in the rank-reducible model, and make use of the fact that the null hypothesis <i>H</i>₀ implies a unidimensional structure of a transformed coefficient matrix for the <i>B</i>-spline basis functions. By evaluating the unidimensional structure, we alleviate the difficulty of testing such hypotheses commonly considered in varying coefficient quantile models. We demonstrate through numerical studies that the proposed method can be much more powerful than the rank score test which is widely used in the quantile regression literature. Supplementary materials for this article are available online.</p

Distributed Decoding From Heterogeneous 1-Bit Compressive Measurements

We develop a communication-efficient distributed estimation for the 1-bit compressive sensing where unknown sparse signals are coded into binary measurements with noises and sign flips. We allow for distinctive sign-flipped probabilities and intensities of noises for measurements collected at different nodes, which raises a heterogeneity issue. We suggest a distributed algorithm through penalized least squares to recover sparse signals. This algorithm is computationally very efficient with only gradient information communicated. The resulting distributed estimate converges after a single iteration even when a lousy initial estimate is provided, and achieves a nearly oracle rate after a constant number of iterations. We prove that, under some mild conditions, with high probability, the distributed estimate approximates the underlying true sparse signal with precision δ after a finite number of iterations, as long as the total sample size N satisfies (s log p)/(δ2N)=O(1), where p is the dimension and s is the number of non-zero elements of the underlying true sparse signals. We establish statistical guarantee for support recovery. Extensive experiments are provided to illustrate the effectiveness of our proposed distributed algorithm. Supplementary materials to this article are available online.</p

Table1_Interannual Variation in the Area and Water Volume of Lakes in Different Regions of the Tibet Plateau and Their Responses to Climate Change.docx

The area and volume changes of 20 lakes that were present during the period 1976–2019 in different parts of the Tibet Plateau were extracted using Landsat remote sensing satellite images on the Google Earth Engine platform. Changes in the water volume of the lakes were analyzed using data from the digital elevation model. Basin scale interpolated meteorological data from the China regional surface meteorological feature dataset and the glacier distribution were used together with GIS technology and spatial statistical methods to reveal the impact of climate change and glacial melting water on the changes occurring in different regions. The results showed that both the area and water volume of the 20 studied lakes were generally stable from 1976–1986, increased significantly from 1986–1991, and decreased significantly from 1991–1995, after which they again began to increase. The increase in both amplitude and rate reached the highest values from 1995–2005, while the rate of increase slowed from 2014–2016. Precipitation and temperature are the main factors that result in the rapid increase of the water volume in closed lakes, but the influence of this phenomenon varies in different areas. The climate is relatively “warm and wet” around the inland enclosed lake areas in the southeast of the plateau where precipitation is the dominant factor and both precipitation and temperature affect the lake water volume in the center of the plateau; however, the climate is comparatively “cold and dry” in the northwest and the increase in glacier meltwater that results from increases in the temperature has a more significant impact.</p

Electrochemiluminescence Cascade Amplification Platform for Detection of Dual-microRNA and Operation of Concatenated Logic Circuit

The detection of multiple biomarkers is of great significance to the accurate diagnosis of diseases. Herein, in this work, we constructed an electrochemiluminescence (ECL) cascade amplification platform for dual acute myocardial infarction (AMI)-related microRNA detection. The Zn2+-dependent DNAzyme digestion reaction initiated by miR-133a and the duplex-specific nuclease (DSN) cleavage circuit initiated by miR-499 were carried out independently to form a fuel hairpin DNA and active initiator strand, respectively, to trigger a hybridization chain reaction, which constituted a two-input-regulated “AND” logic circuit based on single ECL signal output. The use of single signal probe (Ru(bpy)32+) avoided the time-consuming and costly process of multiple signal molecule labeling or modification. The independent operation of the DNAzyme digestion reaction and DSN-assisted target recycling improved the detection efficiency of the system. In addition, the detection of each miRNA had undergone a cascade amplification process, which improved the detection sensitivity for each target. Furthermore, benefitting from the strong complexation of EDTA with Zn2+ and the flexible design of DNA sequences, the two-input “AND” logic gate was extended to a four-input “INHIBIT-AND-INHIBIT” concatenated logic circuit, which broadens the application of the ECL method in logic gates. We anticipate that this cascading amplification strategy can be widely applied in accurate diagnosis of AMI and the construction of ECL-based logic devices

Electrospun Nanofibrous Composite Membranes for Separations

ConspectusElectrospinning is regarded as an efficient method for directly and continuously fabricating nanofibers. The electrospinning process is relatively simple and convenient to operate and can be used to prepare polymer nanofibers for almost all polymer solutions, melts, emulsions, and suspensions with sufficient viscosity. In addition, inorganic nanofibers can also be prepared via electrospinning by adding small amounts of polymers into the inorganic precursors, which are generally regarded as nonspinnable. The diameter of the electrospun nanofibers can be tuned from tens of nanometers to submicrons by changing the spinning parameters. The nonwoven fabric stacked with electrospun fibers is a porous material with interconnected submicron pores, providing a porosity above 80%. However, limited by the unstable rheological properties of the electrospinning fluid, it is difficult to obtain nanofibers stably and continuously with an average diameter of <100 nm, which narrows the separation applications of the electrospun nanofibrous membranes to only microfiltration, air filtration, or use as membrane substrates. Therefore, to fully take advantage of electrospun nanofibrous membranes in other separation applications, electrospun nanofibrous composite (ENC) membranes were developed to improve and optimize their selectivity, permeability, and other separation performances. The composite membranes not only have all the advantages of single-layered or single-component membranes, but also have more flexibility in the choice of functional components.In this account, we summarize the two combination strategies to design and fabricate ENC membranes. One is based on the component combination, in which functional components are homogeneously or heterogeneously mixed in the fiber matrix or modified on the nanofiber surface. The other one is termed as the interfacial combination, in which functional skin layers are fabricated on the top of the electrospun membranes via interfacial deposition or interfacial polymerization, to construct selective barriers. The specific preparation approaches in the two combination strategies are discussed systematically. Additionally, the structural characteristics and separation performances of ENC membranes fabricated via these approaches are also compared and analyzed to clarify their advantages and range of utilization. Subsequently, the six applications of ENC membranes we focus on are demonstrated, including adsorption, membrane distillation, oil/water emulsion separation, nanofiltration, hemodialysis, and pervaporation. To meet their different requirements for separations, our consideration about the choice of combination strategies, related preparation methods, and functional components are discussed based on typical research cases. In the end, we conclude this account with an overview of the challenges in industrial manufacturing, mechanical strength, and interfacial attachment of ENC membranes and prospect their future developments

Electrochemical-Based DNA Logic Devices Regulated by the Diffusion and Intercalation of Electroactive Dyes

Electrochemical-based logic gates are simple to operate, sensitive, controllable, and easy to integrate with silicon-based semiconductor logic devices, showing great application prospects and remaining largely unexplored. Herein, an immobilization-free dual-output electrochemical molecular logic system based on the different diffusivity of electroactive dyes ferrocene (Fc) and methylene blue (MB) toward an indium tin oxide (ITO) electrode under different DNA hybridization reactions was developed. In this system, the hybridization of the catalytic strand IN1 with Fc-modified hairpin DNA H1 triggered an exonuclease III (Exo III) cleavage cycle to obtain free Fc and produce a large number of long double-stranded DNAs via the hybridization chain reaction for intercalating MB, which was previously in the free state. Such a hybridization reaction caused a significant change in the diffusion capacity of MB and Fc toward the ITO electrode, resulting in two electrochemical signals with opposite changes. On this basis, a contrary logic pair library, a parity generator/checker system for differentiating the erroneous bits during data transmission, a parity checker to identify the even/odd natural numbers from 0 to 9, and a series of concatenated logic circuits for meeting the needs of computational complexity were developed. The proposed electrochemical-based molecular logic system greatly expanded the application of the electrochemical method in the construction of logic circuits and provided a conceptual prototype for the development of more advanced and complicated logic devices

Additional file 1 of Heterologous production of 3-hydroxypropionic acid in Methylorubrum extorquens by introducing the mcr gene via a multi-round chromosomal integration system based on cre-lox71/lox66 and transposon

Supplementary Material

Design of One-Dimensional Cadmium Sulfide/Polydopamine Heteronanotube Photocatalysts for Ultrafast Degradation of Antibiotics

The removal of antibiotics in environmental water is of significant importance due to their severe threats to human health and the ecosystem balance but remains as a major challenge. Visible-light photocatalytic degradation provides a desirable way to dispose of antibiotics by natural solar energy. Herein, cadmium sulfide-doped polydopamine (CdS/PDA) heteronanotubes (HNTs) featuring superior photocatalytic capability for ultrafast antibiotic degradation under visible light (14.2 times higher than traditional CdS) was developed via an in situ coordination polymerization strategy. The exceptional catalytic ability was attributed to multiple-level synergistic effects between PDA and CdS. PDA nanotubes (NTs) served as a scaffold for in situ growth of CdS nanocrystals, and the resulting CdS/PDA heterostructures exhibited strong visible-light-harvesting capability and a high transfer rate of photogenerated electron–hole pairs. Furthermore, the photocatalytic mechanism of the CdS/PDA HNTs toward model molecule tetracycline is disclosed in detail, and it is shown that superoxide radical anions (•O2–) and photogenerated holes (h+) play the key roles in the decomposition of tetracycline. Our findings demonstrate that the incorporation of PDA NTs as the scaffold is a feasible strategy to enhance the visible-light sensitivity of photocatalysts used in aqueous antibiotic degradation. This work provides new insights into the development of new functional nanocomposite catalysts with important engineering and environmental applications

Data_Sheet_1_The mobile phone addiction index: Cross gender measurement invariance in adolescents.docx

The Mobile Phone Addiction Index (MPAI) is a short instrument to assess mobile phone addiction. The Chinese version of this scale has been widely used in Chinese students and shows promising psychometric characteristics. The present study tested the construct validity and measurement invariance of the MPAI by gender in middle school adolescents. The data were collected from 1,395 high school students (females, n = 646; M age = 15.3 years). Confirmatory factor analysis (CFA) and multiple-group CFA (MG-CFA) for invariance tests were conducted on the MPAI model which consisted of 17 observed items and 4 latent factors. Findings showed that the data fit the four-factor structure model well for both males and females. Furthermore, configural, metric, scalar, and residual invariance were established by gender. The results indicated that the MPAI has acceptable psychometric properties when used in adolescents. In addition, with the strict invariance requirements being satisfied, the underlying factor scores for MPAI can be meaningfully compared across genders. To our knowledge, this study is the first attempt to test the measurement invariance of the MPAI across male and female adolescents. Our results will support future research on mobile phone addiction in adolescents.</p

Hierarchical and categorical structure in the populations of neurons encoding:

<p>A) Episodic events, B) Face perception, and C) Arm movement. The neurons at the bottom of the hierarchical pyramid represent a common encoding block with broad tuning properties, responding to the most general and abstract features. The next layers of encoding neurons respond to sub-general, yet still multi-feature, properties of the episodic/perception/movement events. The neurons at the top encode the most specific features, allowing for the highly specific discrimination of a particular event, face, or movement direction.</p