Identifying Latent Causal Content for Multi-Source Domain Adaptation

Multi-source domain adaptation (MSDA) learns to predict the labels in target domain data, under the setting that data from multiple source domains are labelled and data from the target domain are unlabelled. Most methods for this task focus on learning invariant representations across domains. However, their success relies heavily on the assumption that the label distribution remains consistent across domains, which may not hold in general real-world problems. In this paper, we propose a new and more flexible assumption, termed \textit{latent covariate shift}, where a latent content variable $\mathbf{z}_c$ and a latent style variable $\mathbf{z}_s$ are introduced in the generative process, with the marginal distribution of $\mathbf{z}_c$ changing across domains and the conditional distribution of the label given $\mathbf{z}_c$ remaining invariant across domains. We show that although (completely) identifying the proposed latent causal model is challenging, the latent content variable can be identified up to scaling by using its dependence with labels from source domains, together with the identifiability conditions of nonlinear ICA. This motivates us to propose a novel method for MSDA, which learns the invariant label distribution conditional on the latent content variable, instead of learning invariant representations. Empirical evaluation on simulation and real data demonstrates the effectiveness of the proposed method

Identifiable Latent Polynomial Causal Models Through the Lens of Change

Causal representation learning aims to unveil latent high-level causal representations from observed low-level data. One of its primary tasks is to provide reliable assurance of identifying these latent causal models, known as identifiability. A recent breakthrough explores identifiability by leveraging the change of causal influences among latent causal variables across multiple environments \citep{liu2022identifying}. However, this progress rests on the assumption that the causal relationships among latent causal variables adhere strictly to linear Gaussian models. In this paper, we extend the scope of latent causal models to involve nonlinear causal relationships, represented by polynomial models, and general noise distributions conforming to the exponential family. Additionally, we investigate the necessity of imposing changes on all causal parameters and present partial identifiability results when part of them remains unchanged. Further, we propose a novel empirical estimation method, grounded in our theoretical finding, that enables learning consistent latent causal representations. Our experimental results, obtained from both synthetic and real-world data, validate our theoretical contributions concerning identifiability and consistency

Phase relationships in the La2O3-SrO-Nb2O5 system

The phase relationships in the La2O3---SrO---Nb2O5 system were studied. The isothermal section at 1400[deg]C of this system was determined. Within this system, two niobates, LaSr2Nb2O8.5 (1-2-2) with hexagonal structure and LaSr2NbO6 (1-2-1) with cubic structure occurred. Same family compounds, YSr2Nb2O8.5 and LaSr2Ta2O8.5, could be also synthesized. In the SrO-rich area of the SrO---Nb2O5 subsystem, a tetragonal solid solution with a composition range of Sr2-4NbO4.5-6.5 (i.e. 66.7-80 at.% SrO) was also observed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29252/1/0000309.pd

Compound formation and melting behavior in theAB compound and rare earth oxide systems

Compound formation in the systems of the covalent compounds BeO, AlN, and SiC withR2O3(rare earth oxides) is described. Tentative phase diagrams of the AlNNd2O3 and AlNEu2O3 systems are presented.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28688/1/0000507.pd

Competition of electronic correlation and reconstruction in La1-xSrxTiO3/SrTiO3 heterostructures

Electronic correlation and reconstruction are two important factors that play a critical role in shaping the magnetic and electronic properties of correlated low-dimensional systems. Here, we report a competition between the electronic correlation and structural reconstruction in La1-xSrxTiO3/SrTiO3 heterostructures by modulating material polarity and interfacial strain, respectively. The heterostructures exhibit a critical thickness (tc) at which a metal-to-insulator transition (MIT) abruptly occurs at certain thickness, accompanied by the coexistence of two- and three-dimensional (2D and 3D) carriers. Intriguingly, the tc exhibits a V-shaped dependence on the doping concentration of Sr, with the smallest tc value at x = 0.5. We attribute this V-shaped dependence to the competition between the electronic reconstruction (modulated by the polarity) and the electronic correlation (modulated by strain), which are borne out by the experimental results, including strain-dependent electronic properties and the evolution of 2D and 3D carriers. Our findings underscore the significance of the interplay between electronic reconstruction and correlation in the realization and utilization of emergent electronic functionalities in low-dimensional correlated systems

Study on the tropism of six species of insect pests in stored grain to different colors

The tropism of six species of insect pests in stored grain to six kinds of colours was researched in laboratory by color correction.The results showed that the tropism of six species of insect pests in stored grain to different colors mostly changed with time, and the behavioral responses of the Tribolium castaneum(Herbst)、Tribolium confusum Jacquelin du Val、Sitophilus oryzae (linnaeus)、Sitophilus zeamais Motschulsky to different colors were significantly different within a specific period of time (P≤0.05).Red、orange and black had obvious attracting effect on Tribolium castaneum (Herbst), with the highest trapping rates of 76.23%、39.55%、49.57%; Red and black had obvious attracting effect on Sitophilus zeamais Motschulsky,with the highest trapping rates of 38.48%、38.67%.The Liposcelis bostrychophila Bodonnel and Liposcelis decolor (Pearman) showed evasiveness to the most of the six colors tested.Red and purple had evident evasive effects on the Liposcelis bostrychophila Bodonnel and Liposcelis decolor (Pearman), with the highest evasive rates of 70.29% and 54.46%.The results can provide reference for the development of color traps to trap and monitor pests in stored grain

Design & Optimization of the HV divider for JUNO 20-inch PMT

The Jiangmen Underground Observatory (JUNO) is a 20-kton liquid scintillator detector that employs 20,000 20-inch photomultiplier tubes (PMTs) as photon sensors, with 5,000 dynode-PMTs from HAMAMATSU Photonics K.K. (HPK), and 15,000 MCP-PMTs from North Night Vision Technology (NNVT) installed in pure water. JUNO aims to provide long-lasting and the best performance operation by utilizing a high-transparency liquid scintillator, high detection efficiency PMTs, and specially designed electronics including water-proof potting for the high voltage (HV) dividers of PMTs. In this paper, we present a summary of the design and optimization of HV dividers for both types of 20-inch PMTs, which includes collection efficiency, charge resolution, HV divider current, pulse shape, and maximum amplitude restriction. We have developed and finalized four schemes of the HV divider for different scenarios, including the final version selected by JUNO. All 20,000 20-inch PMTs have successfully undergone production and burning tests.Comment: 14pages,28figure

Surface chromium on Terracotta Army bronze weapons is neither an ancient anti-rust treatment nor the reason for their good preservation.

For forty years, there has been a widely held belief that over 2,000 years ago the Chinese Qin developed an advanced chromate conversion coating technology (CCC) to prevent metal corrosion. This belief was based on the detection of chromium traces on the surface of bronze weapons buried with the Chinese Terracotta Army, and the same weapons' very good preservation. We analysed weapons, lacquer and soils from the site, and conducted experimental replications of CCC and accelerated ageing. Our results show that surface chromium presence is correlated with artefact typology and uncorrelated with bronze preservation. Furthermore we show that the lacquer used to cover warriors and certain parts of weapons is rich in chromium, and we demonstrate that chromium on the metals is contamination from nearby lacquer after burial. The chromium anti-rust treatment theory should therefore be abandoned. The good metal preservation probably results from the moderately alkaline pH and very small particle size of the burial soil, in addition to bronze composition