The importance of discovering significant variables from a large candidate pool is now widely recognized in many fields. There exist a number of algorithms for variable selection in the literature. ...Some are computationally efficient but only provide a necessary condition for, not a sufficient and necessary condition for, testing if a variable contributes or not to the system output. The others are computationally expensive. The goal of the paper is to develop a directional variable selection algorithm that performs similar to or better than the leading algorithms for variable selection, but under weaker technical assumptions and with a much reduced computational complexity. It provides a necessary and sufficient condition for testing if a variable contributes or not to the system. In addition, since indicators for redundant variables aren’t exact zero’s, it is difficult to decide variables whether are redundant or not when the indicators are small. This is critical in the variable selection problem because the variable is either selected or unselected. To solve this problem, a penalty optimization algorithm is proposed to ensure the convergence of the set. Simulation and experimental research verify the effectiveness of the directional variable selection method proposed in this paper.
A measurement of electron antineutrino oscillation by the Daya Bay Reactor Neutrino Experiment is described in detail. Six 2.9-GWth nuclear power reactors of the Daya Bay and Ling Ao nuclear power ...facilities served as intense sources of ν¯e’s. Comparison of the ν¯e rate and energy spectrum measured by antineutrino detectors far from the nuclear reactors (∼1500–1950 m) relative to detectors near the reactors (∼350–600 m) allowed a precise measurement of ν¯e disappearance. More than 2.5 million ν¯e inverse beta-decay interactions were observed, based on the combination of 217 days of operation of six antineutrino detectors (December, 2011–July, 2012) with a subsequent 1013 days using the complete configuration of eight detectors (October, 2012–July, 2015). The ν¯e rate observed at the far detectors relative to the near detectors showed a significant deficit, R=0.949±0.002(stat)±0.002(syst). The energy dependence of ν¯e disappearance showed the distinct variation predicted by neutrino oscillation. Analysis using an approximation for the three-flavor oscillation probability yielded the flavor-mixing angle sin22θ13=0.0841±0.0027(stat)±0.0019(syst) and the effective neutrino mass-squared difference of |Δmee2|=(2.50±0.06(stat)±0.06(syst))×10−3 eV2. Analysis using the exact three-flavor probability found Δm322=(2.45±0.06(stat)±0.06(syst))×10−3 eV2 assuming the normal neutrino mass hierarchy and Δm322=(−2.56±0.06(stat)±0.06(syst))×10−3 eV2 for the inverted hierarchy.
•A Kautz-basis-expansion based Hammerstein system identification method is proposed.•Separable least squares is adopted to estimate linear and nonlinear parameters.•Best linear approximation is ...presented to choose initial values of pole parameters.•LM algorithm is presented for the optimization of pole and nonlinear parameters.
This paper proposes a novel Hammerstein system identification method based on the Kautz basis expansion and the separable least squares method. In this method, to reduce the parameters to be identified, the impulse response function (IRF) of the linear subsystem is expanded by orthogonal Kautz functions, the pole parameters among which should be optimized. In addition, to improve the condition number of matrix during the identification process, the separable least squares optimization method is adopted to estimate the linear and nonlinear parameters. The separable least squares approach can simultaneously estimate the linear and nonlinear parameters in a least squares framework. Furthermore, based on the best linear approximation, an effective method for the choice of initial values of pole parameters is presented, and based on the back propagation through-time technique and the Levenberg-Marquardt algorithm, an optimization algorithm for pole and nonlinear parameters is presented in this paper. The simulation studies verify the effectiveness of the proposed Hammerstein system identification method.
•The spin diffusion length of Ir and the spin mixing conductance of CoFeB/Ir interface were obtained.•The spin mixing conductance is 2.14 × 1019 m−2 and the spin diffusion length is only 1.34 nm.•Ir ...possesses a strong spin-orbit coupling and is quite suitable for Ir-based spintronic materials engineering.
The spin pumping effect of CoFeB/Ir bilayers has been investigated via the broadband ferromagnetic resonance measurement. With increasing the thickness of heavy metal Ir layer, the Gilbert damping factor of 8 nm CoFeB film increases from 7 × 10−3 to 1.1 × 10−2, and the additional damping factors induced by the spin pumping effect quickly reaches its saturation value. According to the spin pumping theory, the spin mixing conductance of CoFeB/Ir and the spin diffusion length of Ir were obtained. The spin mixing conductance is 2.14 × 1019 m−2. Furtherly, the spin diffusion length is only 1.34 nm, which is quite shorter compared with the heavy metal Pt. Our results reveal the existence of the strong spin-orbit coupling in the heavy metal Ir, which can be a potential material for the application in spintronic devices.
When MgO+ZrO
2
were used as a sintering aid to SiC ceramics, it was found that ZrO
2
reacted with SiC and MgO to form ZrC and a magnesium silicate. This reaction may provide a new route to synthesize ...ZrC or prepare ZrC/SiC composites by reaction sintering using ZrO
2
, SiC, and MgO as starting materials. In the present work, formation process of the ZrC phase in the SiC–MgO–ZrO
2
system was addressed. Subsolidus phase relations at 1550 °C of the SiC–MgO–ZrO
2
system and the related SiC–SiO
2
–ZrC–ZrO
2
–MgO (Si–Zr–Mg–O–C) system were investigated.
INTRODUCTION
The molecular mechanisms that contribute to sex differences, in particular female predominance, in Alzheimer's disease (AD) prevalence, symptomology, and pathology, are incompletely ...understood.
METHODS
To address this problem, we investigated cellular metabolism and immune responses (“immunometabolism endophenotype”) across AD individuals as a function of sex with diverse clinical diagnosis of cognitive status at death (cogdx), Braak staging, and Consortium to Establish a Registry for AD (CERAD) scores using human cortex metabolomics and transcriptomics data from the Religious Orders Study / Memory and Aging Project (ROSMAP) cohort.
RESULTS
We identified sex‐specific metabolites, immune and metabolic genes, and pathways associated with the AD diagnosis and progression. We identified female‐specific elevation in glycerophosphorylcholine and N‐acetylglutamate, which are AD inflammatory metabolites involved in interleukin (IL)‐17 signaling, C‐type lectin receptor, interferon signaling, and Toll‐like receptor pathways. We pinpointed distinct microglia‐specific immunometabolism endophenotypes (i.e., lipid‐ and amino acid‐specific IL‐10 and IL‐17 signaling pathways) between female and male AD subjects. In addition, female AD subjects showed evidence of diminished excitatory neuron and microglia communications via glutamate‐mediated immunometabolism.
DISCUSSION
Our results point to new understanding of the molecular basis for female predominance in AD, and warrant future independent validations with ethnically diverse patient cohorts to establish a likely causal relationship of microglial immunometabolism in the sex differences in AD.
Highlights
Sex‐specific immune metabolites, gene networks and pathways, are associated with Alzheimer's disease pathogenesis and disease progression.
Female AD subjects exhibit microglial immunometabolism endophenotypes characterized by decreased glutamate metabolism and elevated interleukin‐10 pathway activity.
Female AD subjects showed a shift in glutamate‐mediated cell‐cell communications between excitatory neurons to microglia and astrocyte.
Objectives: Severe lithium toxicity is commonly observed in older people. We aimed to determine the extent to which age is associated with increased severity of chronic lithium poisoning and of which ...a range of possible factors might explain the associations.
Method: We did a retrospective review of patients aged ≥15 years old with serum lithium concentrations ≥1.3 mmol/L from three hospitals. Clinical details, treatment and outcomes were recorded. eGFR, creatinine and lithium clearance were calculated. The severity of lithium toxicity was graded into five categories (Amdisen score). ANOVA was used to quantify the association between age and severity. Spearman correlation coefficient was used to explore relationships between age and different factors expected to alter severity. Ordinal regression analysis was used to determine the interdependence of age and these factors and age on severity of lithium toxicity.
Results: From 2008-2018, there were 242 patients with a median age of 56.5 years (IQR: 41-69). There were 156 females (64%). There was a statistically significant association between Amdisen severity scores and age (p = .0004). The median calculated eGFR was 65 mL/min/1.73 m
2
(IQR: 41-91) with a corresponding estimated lithium clearance of 18 mL/min (IQR: 13.8-22.8). There was no correlation of age with initial serum lithium concentration (p = .76). There was a strong correlation between age and estimated lithium clearance (r = -0.72, 95% CI: -0.78 to -0.66, p < .001), lithium daily dose (r = -0.65, 95% CI: -0.72 to -0.57, p < .0001) and lithium concentration/dose (r = 0.62, 95% CI: 0.53-0.69, p < .0001). There was a weak correlation between age and infection (r = 0.18, 95% CI: 0.04-0.31, p = .009) and drug interactions (r = 0.25, 95% CI: 0.11-0.37, p = .0003). Ordinal regression indicated the independent predictors for severity of lithium toxicity were lithium concentration (p < .0001) and lithium clearance (p = .03) adjusted for age and dose.
Conclusions: Despite lower lithium doses, older patients had more severe toxicity. Increased severity of lithium toxicity in the elderly is largely explainable by decreased lithium clearance from multiple factors such as age-related decline in renal function, drug interactions and infection.
We report Kondo resonances in the conduction of single-molecule transistors based on transition metal coordination complexes. We find Kondo temperatures in excess of 50 K, comparable to those in ...purely metallic systems. The observed gate dependence of the Kondo temperature is inconsistent with observations in semiconductor quantum dots and a simple single-dot-level model. We discuss possible explanations of this effect, in light of electronic structure calculations.
Thymic stromal lymphopoietin (TSLP), an IL7-like cytokine produced by bronchial epithelial cells is upregulated in asthma and induces dendritic cell maturation supporting a Th2 response. ...Environmental pollutants, including tobacco smoke and diesel exhaust particles upregulate TSLP suggesting that TSLP may be an interface between environmental pollution and immune responses in asthma. Since asthma is prevalent in urban communities, variants in the TSLP gene may be important in asthma susceptibility in these populations.
To determine whether genetic variants in TSLP are associated with asthma in an urban admixed population. METHODOLOGY AND MAIN RESULTS: Ten tag-SNPs in the TSLP gene were analyzed for association with asthma using 387 clinically diagnosed asthmatic cases and 212 healthy controls from an urban admixed population. One SNP (rs1898671) showed nominally significant association with asthma (odds ratio (OR) = 1.50; 95% confidence interval (95% CI): 1.09-2.05, p = 0.01) after adjusting for age, BMI, income, education and population stratification. Association results were consistent using two different approaches to adjust for population stratification. When stratified by smoking status, the same SNP showed a significantly increased risk associated with asthma in ex-smokers (OR = 2.00, 95% CI: 1.04-3.83, p = 0.04) but not significant in never-smokers (OR = 1.34; 95% CI: 0.93-1.94, p = 0.11). Haplotype-specific score test indicated that an elevated risk for asthma was associated with a specific haplotype of TSLP involving SNP rs1898671 (OR = 1.58, 95% CI: 1.10-2.27, p = 0.01). Association of this SNP with asthma was confirmed in an independent large population-based cohort consortium study (OR = 1.15, 95% CI: 1.07-1.23, p = 0.0003) and the results stratified by smoking status were also validated (ex-smokers: OR = 1.21, 95% CI: 1.08-1.34, p = 0.003; never-smokers: OR = 1.06, 95% CI: 0.94-1.17, p = 0.33).
Genetic variants in TSLP may contribute to asthma susceptibility in admixed urban populations with a gene and environment interaction.
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