A Bayesian propensity score adjustment for latent variable modeling and MCMC algorithm

The estimation of the differences among groups in observational studies is frequently inaccurate owing to a bias caused by differences in the distributions of covariates. In order to estimate the average treatment effects when the treatment variable is binary, Rosenbaum and Rubin [1983. The central role of the propensity score in observational studies for causal effects. Biometrika 70, 41-55] proposed an adjustment method for pre-treatment variables using propensity scores. Imbens [2000. The role of the propensity score in estimating dose-response functions. Biometrika 87, 706-710] extended the propensity score methodology for estimation of average treatment effects with multivalued treatments.However, these studies focused only on estimating the marginal mean structure. In many substantive sciences such as the biological and social sciences, a general estimation method is required to deal with more complex analyses other than regression, such as testing group differences on latent variables. For latent variable models, the EM algorithm or the traditional Monte Carlo methods are necessary. However, in propensity score adjustment, these methods cannot be used because the full distribution is not specified.In this paper, we propose a quasi-Bayesian estimation method for general parametric models that integrate out the distributions of covariates using propensity scores. Although the proposed Bayes estimates are shown to be consistent, they can be calculated by existing Markov chain Monte Carlo methods such as Gibbs sampler. The proposed method is useful to estimate parameters in latent variable models, while the previous methods were unable to provide valid estimates for complex models such as latent variable models.We also illustrated the procedure using the data obtained from the US National Longitudinal Survey of Children and Youth (NLSY1979-2002) for estimating the effect of maternal smoking during pregnancy on the development of the child's cognitive functioning.     

Power swing analysis in a future metropolitan electric power system on a contingent trip of cryogenic high-power cables

A cryogenic power cable is expected to be capable of carrying bulk power as a main transmission line in a future metropolitan electric power system. It is important to establish a strategy of how to sustain power supply when such a highly densified power supply route trips from the network due to contingency. It is proposed here that the bulk power transmitted by the cryogenic cable could be distributed into the parallel conventional transmission lines by suitable circuit breaker operations in the system. In this process, power-flow routes are forced to be changed with a remarkable modification in the system configuration. In this paper, the power swings associated with the large power-flow change following contingent faults are analyzed by means of a transient network analyzer. It is found that the proposed system modification could be realized without any harmful power swing if the parameters in generators as well as in control devices have conventional magnitudes. It is shown also by simulations that the margin to occurrence in an unstable power swing is left sufficient even if the parameters deviate somewhat from the present magnitudes.     

Magnetotransport of two-dimensional electron gas in Si/SiGe modulation doped structures grown by gas source molecular beam epitaxy

We have characterized two-dimensional electron gases (2DEGs) in Si/SiGe modulation doped structures grown by gas source molecular beam epitaxy. Hall bar structures were fabricated to characterize the structures and magnetotransport measurements were carried out at temperatures down to 0.4 K. Pronounced Shubnikov-de Haas oscillations were observed in the longitudinal magnetoresistance, indicative of high quality 2DEG in the channel. Electron mobilities up to 87,000 cm² V⁻¹ s⁻¹ with sheet densities about 7 × 10¹¹ cm⁻² were obtained at low temperature. Dingle plots of the magnetoresistance vs reciprocal magnetic field were utilized to determine the single-particle relaxation times in order to investigate scattering mechanisms in these structure. The ratio of the transport scattering time derived from electron mobility to the single-particle relaxation time is of the order of 10, indicating that remote impurity scattering is a dominant factor limiting the mobility of our structures. The behaviour of the magnetotransport data is discussed using a model for parallel conduction.     

Evaluation of constructed wetlands by wastewater purification ability and greenhouse gas emissions.

Domestic wastewater is a significant source of nitrogen and phosphorus, which cause lake eutrophication. Among the wastewater treatment technologies, constructed wetlands are a promising low-cost means of treating point and diffuse sources of domestic wastewater in rural areas. However, the sustainable operation of constructed wetland treatment systems depends upon a high rate conversion of organic and nitrogenous loading into their metabolic gaseous end products, such as N2O and CH4. In this study, we examined and compared the performance of three typical types of constructed wetlands: Free Water Surface (FWS), Subsurface Flow (SF) and Vertical Flow (VF) wetlands. Pollutant removal efficiency and N2O and CH4 emissions were assessed as measures of performance. We found that the pollutant removal rates and gas emissions measured in the wetlands exhibited clear seasonal changes, and these changes were closely associated with plant growth. VF wetlands exhibited stable removal of organic pollutants and NH3-N throughout the experiment regardless of season and showed great potential for CH4 adsorption. SF wetlands showed preferable T-N removal performance and a lower risk of greenhouse gas emissions than FWS wetlands. Soil oxidation reduction potential (ORP) analysis revealed that water flow structure and plant growth influenced constructed wetland oxygen transfer, and these variations resulted in seasonal changes of ORP distribution inside wetlands that were accompanied by fluctuations in pollutant removal and greenhouse gas emissions.     

Formation of low-resistivity poly-Si and SiNx films by Cat-CVD for ULSI application

In this paper, bulk-Si metal–oxide–semiconductor field effect transistors (MOSFETs) are fabricated using the catalytic chemical vapor deposition (Cat-CVD) method as an alternative technology to the conventional high-temperature thermal chemical vapor deposition. Particularly, formation of low-resistivity phosphorus (P)-doped poly-Si films is attempted by using Cat-CVD-deposited amorphous silicon (a-Si) films and successive rapid thermal annealing (RTA) of them. Even after RTA processes, neither peeling nor bubbling are observed, since hydrogen contents in Cat-CVD a-Si films can be as low as 1.1%. Both the crystallization and low resistivity of 0.004 Ω·cm are realized by RTA at 1000 °C for only 5 s. It is also revealed that Cat-CVD SiN_x films prepared at 250 °C show excellent oxidation resistance, when the thickness of films is larger than approximately 10 nm for wet O₂ oxidation at 1100 °C. It is found that the thickness required to stop oxygen penetration is equivalent to that for thermal CVD SiN_x prepared at 750 °C. Finally, complementary MOSFETs (CMOSs) of single-crystalline Si were fabricated by using Cat-CVD poly-Si for gate electrodes and SiN_x films for masks of local oxidation of silicon (LOCOS). At 3.3 V operation, less than 1.0 pA μm⁻¹ of OFF leakage current and ON/OFF ratio of 10⁷–10⁸ are realized, i.e. the devices can operate similarly to conventional thermal CVD process.     

Robust stabilization of a magnetic suspension system using H∞ Control Theory

This paper presents the robust control design of a magnetic suspension system for a flexible beam which is a simplified model of an elastic rotor in a magnetic bearing system. To stabilize this magnetic suspension system which is unstable in nature, the H^infin; control theory is applied for a design of the control system. To apply the H^infin; control theory, a statespace model of an augmented plant with frequency-weighting functions is constructed. This augmented plant has two inputs which are the exogenous inputs and the control inputs, and two outputs which are the sensor outputs and the regulated outputs. Here we consider the mixed sensitivity problem. The H^infin; controller is implemented by a digital controller which is able to execute the computations very quickly. For the evaluation of the control performance, several experiments are made. The robustness of the closed-loop system is confirmed by the experimental results. The result of this study is useful for the control design of a magnetic bearing system.     

Oligosaccharide structures formed during the hydrolysis of lactose by Aspergillus oryzae β-galactosidase

Di-, tri-, tetra-, penta- and hexasaccharides were formed during the hydrolysis of lactose by transgalactosylation reaction of Aspergillus oryzae β-galactosidase. In this study the isolation and characterization of the major constituents of tri-, tetra- and pentasaccharides are described. The structure elucidation of 3 tri-, 2 tetra- and 1 pentasaccharides was carried out by methylation analysis, mass spectrometry and ¹³C-nmr spectrometry. The trisaccharides are $\text{O-β-}\text{d}\text{-}\text{galactopyranosyl}\text{-(1 → 3)-O-β-}\text{d}\text{-}\text{galactopyranosyl}\text{-(1 → 4)-}\text{d}\text{-}\text{glucose}\text{(3′-}\text{galactosyl-lactose}\text{)}$, $\text{O-β-}\text{d}\text{-}\text{galactopyranosyl}\text{-(1 → 6)-β-}\text{d}\text{-}\text{galactopyranosyl}\text{-(1 → 4)-}\text{d}\text{-}\text{glucose}\text{(6′-}\text{galactosyl-lactose}\text{)}$ and $\text{O-β-}\text{d}\text{-}\text{galactopyranosyl}\text{-(1 → 4)-O-[β-}\text{d}\text{-}\text{galactopyranosyl}\text{-(1 → 6)]-}\text{d}\text{-}\text{glucose}\text{(4,6-}\text{digalactosyl-glucose}\text{)}$. Tetrasaccharides are $\text{O-β-}\text{d}\text{-}\text{galactopyranosyl}\text{-(1 → 6)-O-β-}\text{d}\text{-}\text{galactopyranosyl}\text{-(1 → 6)-O-β-}\text{d}\text{-}\text{galactopyranosyl}\text{-(1 → 4)-}\text{d}\text{-}\text{glucose}$ and $\text{O-β-}\text{d}\text{-}\text{galactopyranosyl}\text{-(1 → 6)-O-β-}\text{d}\text{-}\text{galactopyranosyl}\text{-(1 → 3)}$ [or $\text{O-β-}\text{d}\text{-}\text{galactopyranosyl}\text{-(1 → 3)-O-β-}\text{d}\text{-}\text{galactopyranosyl}\text{-(1 → 6)]-O-β-}\text{d}\text{-}\text{galactopyranosyl}\text{-(1 → 4)-}\text{d}\text{-}\text{glucose}$. Pentasaccharide is $\text{O-β-}\text{d}\text{-}\text{galactopyranosyl}\text{-(1 → 6)-O-β-}\text{d}\text{-}\text{galactopyranosyl}\text{-(1 → 6)-O-β-}\text{d}\text{-}\text{galactopyranosyl}\text{-(1 → 6)-O-β-}\text{d}\text{-}\text{galactopyranosyl}\text{-(1 → 4)-}\text{d}\text{-}\text{glucose}$.     

An Engineered Biliverdin-Compatible Cyanobacteriochrome Enables a Unique Ultrafast Reversible Photoswitching Pathway

Cyanobacteriochromes (CBCRs) are promising optogenetic tools for their diverse absorption properties with a single compact cofactor-binding domain. We previously uncovered the ultrafast reversible photoswitching dynamics of a red/green photoreceptor AnPixJg2, which binds phycocyanobilin (PCB) that is unavailable in mammalian cells. Biliverdin (BV) is a mammalian cofactor with a similar structure to PCB but exhibits redder absorption. To improve the AnPixJg2 feasibility in mammalian applications, AnPixJg2_BV4 with only four mutations has been engineered to incorporate BV. Herein, we implemented femtosecond transient absorption (fs-TA) and ground state femtosecond stimulated Raman spectroscopy (GS-FSRS) to uncover transient electronic dynamics on molecular time scales and key structural motions responsible for the photoconversion of AnPixJg2_BV4 with PCB (Bpcb) and BV (Bbv) cofactors in comparison with the parent AnPixJg2 (Apcb). Bpcb adopts the same photoconversion scheme as Apcb, while BV4 mutations create a less bulky environment around the cofactor D ring that promotes a faster twist. The engineered Bbv employs a reversible clockwise/counterclockwise photoswitching that requires a two-step twist on ~5 and 35 picosecond (ps) time scales. The primary forward P_fr → P_o transition displays equal amplitude weights between the two processes before reaching a conical intersection. In contrast, the primary reverse P_o → P_fr transition shows a 2:1 weight ratio of the ~35 ps over 5 ps component, implying notable changes to the D-ring-twisting pathway. Moreover, we performed pre-resonance GS-FSRS and quantum calculations to identify the Bbv vibrational marker bands at ~659,797, and 1225 cm⁻¹. These modes reveal a stronger H-bonding network around the BV cofactor A ring with BV4 mutations, corroborating the D-ring-dominant reversible photoswitching pathway in the excited state. Implementation of BV4 mutations in other PCB-binding GAF domains like AnPixJg4, AM1_1870g3, and NpF2164g5 could promote similar efficient reversible photoswitching for more directional bioimaging and optogenetic applications, and inspire other bioengineering advances.     

Temperature Dependence of Thermal Reflection Behavior of Al2O3–TiO2 Multilayer Thermal Energy Window Coating

An Al₂O₃–TiO₂ multilayer-coated sapphire thermal energy window coating has been fabricated using an ultra-high-speed vacuum sputtering method. Thermal reflection spectra of the coated material in the wavelength range from 1.43 to 3.33 μm are measured in ambient air at temperatures of 298, 773, and 1173 K. The result shows that the light reflectance of ∼70% is achieved using a layered structure and this performance continues up to 1173 K. Thermal reflection energy of the coated material at T =1173 K is estimated to be about three times higher than that of uncoated sapphire, suggesting the potential of this coating to control thermal radiation energy.