This article looks at participatory viewers’ engagement with foreign language video contents facilitated by the
interface on a video-sharing website in China. Using the video of the Chinese athlete ...Sun Yang’s public hearing hosted on Bilibili as a case study, this article investigates Bilbili users’
-based translational efforts and their engagement with the translation problem inherent in the hearing through multimodal discourse analysis, with supportive analysis of individual users’
footprints from a diachronic perspective.
-based viewer activities are approached from the social semiotic perspective and situated in the distribution stratum of the communicative practice of video sharing, with a view to understand participatory viewers’ meaning making processes in their consumption of videos on the
interface. The findings show a manifest willingness from participatory viewers to engage with the dual translation problem specific to this case, who submit different kinds of translational inputs onto the video frame in response to the untranslated video and articulate translation-related discourses as prompted by the inherent translation problem in the video. This study contributes to social semiotic discourse analysis of
-mediated communication as well as to non-professional translation studies through a focus on novel translation practices emergent in the Chinese context of participatory viewing.
Theoretical developments on cross validation (CV) have mainly focused on selecting one among a list of finite-dimensional models (e.g., subset or order selection in linear regression) or selecting a ...smoothing parameter (e.g., bandwidth for kernel smoothing). However, little is known about consistency of cross validation when applied to compare between parametric and nonparametric methods or within nonparametric methods. We show that under some conditions, with an appropriate choice of data splitting ratio, cross validation is consistent in the sense of selecting the better procedure with probability approaching 1. Our results reveal interesting behavior of cross validation. When comparing two models (procedures) converging at the same nonparametric rate, in contrast to the parametric case, it turns out that the proportion of data used for evaluation in CV does not need to be dominating in size. Furthermore, it can even be of a smaller order than the proportion for estimation while not affecting the consistency property.
MAXIMUM Lq-LIKELIHOOD ESTIMATION Ferrari, Davide; Yang, Yuhong
The Annals of statistics,
04/2010, Letnik:
38, Številka:
2
Journal Article
Recenzirano
Odprti dostop
In this paper, the maximum L q -likelihood estimator (ML q E), a new parameter estimator based on nonextensive entropy Kibernetika 3 (1967) 30–35 is introduced. The properties of the ML q E are ...studied via asymptotic analysis and computer simulations. The behavior of the ML q E is characterized by the degree of distortion q applied to the assumed model. When q is properly chosen for small and moderate sample sizes, the ML q E can successfully trade bias for precision, resulting in a substantial reduction of the mean squared error. When the sample size is large and q tends to 1, a necessary and sufficient condition to ensure a proper asymptotic normality and efficiency of ML q E is established.
A traditional approach to statistical inference is to identify the true or best model first with little or no consideration of the specific goal of inference in the model identification stage. Can ...the pursuit of the true model also lead to optimal regression estimation? In model selection, it is well known that BIC is consistent in selecting the true model, and AIC is minimax-rate optimal for estimating the regression function. A recent promising direction is adaptive model selection, in which, in contrast to AIC and BIC, the penalty term is data-dependent. Some theoretical and empirical results have been obtained in support of adaptive model selection, but it is still not clear if it can really share the strengths of AIC and BIC. Model combining or averaging has attracted increasing attention as a means to overcome the model selection uncertainty. Can Bayesian model averaging be optimal for estimating the regression function in a minimax sense? We show that the answers to these questions are basically in the negative: for any model selection criterion to be consistent, it must behave suboptimally for estimating the regression function in terms of minimax rate of covergence; and Bayesian model averaging cannot be minimax-rate optimal for regression estimation.
The utilization of gypsum and biomass in environmental remediation has become a novel approach to promote waste recycling. Generally, raw waste materials exhibit limited adsorption capacity for heavy ...metal ions (HMIs) and often result in poor solid–liquid separation. In this study, through co-pyrolysis with corncob waste, titanium gypsum (TiG) was transformed into magnetic adsorbents (GCx, where x denotes the proportion of corncob in the gypsum–corncob mixture) for the removal of Cd(II) and Pb(II). GC10, the optimal adsorbent, which was composed primarily of anhydrite, calcium sulfide, and magnetic Fe3O4, exhibited significantly faster adsorption kinetics (rate constant k1 was 218 times and 9 times of raw TiG for Cd(II) and Pb(II)) and higher adsorption capacity (Qe exceeded 200 mg/g for Cd(II) and 400 mg/g for Pb(II)) than raw TiG and previous adsorbents. Cd(II) removal was more profoundly inhibited in a Cd(II) + Pb(II) binary system, suggesting that GC10 showed better selectivity for Pb(II). Moreover, GC10 could be easily separated from purified water for further recovery, due to its high saturation magnetization value (6.3 emu/g). The superior removal capabilities of GC10 were due to adsorption and surface precipitation of metal sulfides and metal sulfates on the adsorbent surface. Overall, these waste-derived magnetic adsorbents provide a novel and sustainable approach to waste recycling and the deep purification of multiple HMIs.
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●Raw TiG showed no obvious adsorption for Cd(II) but reduced Pb(II) below 4 mg/L.●Co-pyrolysis with corncob transformed TiG to highly-efficient magnetic adsorbents.●GC10 showed higher selectivity for Pb(II) in Pb(II)+Cd(II) binary system.●HMIs removal was governed by surface precipitation of PbS, CdS and PbSO4.
Soil-related problems have grown up to be a major threat to human society. Scientific evaluation is helpful to understand the status of soil pollution and provide reference to further work. In this ...situation, Liaoning Province, a typical industrial and agricultural province in Northeast China, was selected as a case study region. It reviewed 200 studies published between 2010 and 2020 and recorded related data of soil heavy metal. It used model method and index method to evaluate the agricultural region. The comprehensive assessment score of Liaoning pollution level was 0.8998. Dalian was 0.9536, ranking first among the 14 cities. Huludao and Jinzhou were 0.7594 respectively, ranked the last. Heavy metal accumulation in different cities stemmed from different sources, including weathering of parent materials, industrial wastes, sewage irrigation, and mining activities. In general, the pollution level of heavy metal in Liaoning was at low risk level, but it still needs to pay attention to the health risk of heavy metal and the input of heavy metal into the soil, especially cadmium (Cd). This study provides a comprehensive assessment of soil heavy metal pollution in Liaoning, while identifying policy recommendations for pollution mitigation and environmental management.
Abstract
Developing non-metallic contrast agents of clinically applied magnetic resonance imaging (MRI) is an alternative strategy to reduce the toxicity of heavy metal elements in current MRI ...agents. These non-metallic MRI agents usually generate contrasts by unpaired electrons, which are prone to be deactivated by in vivo radical scavenging pathways. Since the unpaired electrons in conjugated polymers exhibit satisfying stability for in vivo imaging, developing conjugated polymers based MRI agents may solve the in vivo stability problem of current non-metallic agents. However, MRI-active properties have not been reported in existing conjugated polymers yet. Herein we report on MRI-active conjugated polymer nanoparticles based on polypyrrole (PPy), which can be used for in vivo imaging. Our method not only introduce a kind of non-metallic MRI agents but extends the applications of conjugated polymers from optical imagings to MRI.
Precise prediction of hydrogen (H) isotope fractionations among different substances is a long-standing challenge in isotope geochemistry, as it needs treatments beyond the harmonic approximation. ...Path-integral molecular dynamics (PIMD) simulations have recently been proved to be valid in predicting equilibrium isotope fractionations for light elements. However, the lack of reliable force fields hinders the application of PIMD to the condensed phases. In this work, the deep potential models trained on the first-principles molecular dynamics (FPMD) data are applied to PIMD simulations to determine the D/H and 18O/16O isotope fractionation factors between brucite and water. To quantitatively assess the influence of quantum effects, the D/H and 18O/16O isotope fractionations between brucite and water are also determined under the framework of harmonic approximation.
By comparing the results of the PIMD and those of harmonic calculations, we find that H and O atoms in brucite and water are strongly affected by the anharmonic effects. The accuracy of the harmonic isotope fractionations mainly depends on the cancellation percentage of the anharmonic effects on the reduced partition function ratios (RPFRs) of the two substances. The isotope fractionations predicted by PIMD simulations are close to the experimental results at high temperatures. However, at low temperatures, the predicted isotope fractionations are different from those of experiments. The discrepancies are attributed to the approximations in the density functional theory (DFT) functionals used in this work, i.e., the inaccuracy in predicting the proton positions in brucite and water. Moreover, we find that the H isotope fractionations are extremely sensitive to the change of pressure. The direction of H isotope fractionation between brucite and water (at 300 K) will be even inversed as the pressure increases to more than 3 GPa. This strong pressure sensitivity may be a common characteristic of hydrous minerals and water systems. Therefore, the extrapolated H isotope fractionations used in the studies of dehydration of subducting slabs or deep Earth H distribution based on the isotope fractionations under low pressures may need to be rechecked.
There are large discrepancies existing in equilibrium Mg isotope fractionation calculations and experimental investigations for cases related to mineral vs. solution. To clarify this confusing issue, ...a newly designed cluster-model-based quantum chemistry method, i.e., volume variable cluster model (VVCM), is used to provide equilibrium Mg isotope fractionation factors between Mg-bearing carbonates (calcite, aragonite, dolomite and magnesite), amorphous calcium carbonates (ACCs), brucite and aqueous species (i.e., Mg2+(aq), MgHCO3+(aq) and MgOH+(aq)). We find that local configuration sampling of aqueous species is essential to provide precise fractionations between mineral and solution. The phonon-based periodic boundary method is also used for several minerals and it obtains very similar fractionations with VVCM results.
Our results are very close to those of Pinilla et al. (2015) although via completely different approaches. Both of them have included the effect of local configuration disorder. However, both of them are significantly different from some of experimental results for cases of carbonates vs. solutions. The existence of various Mg-bearing species in fluids of experiments, the direct incorporation of hydrated Mg2+ into the solids, the Mg2+ concentration effect, and the existence of intermediate precursors (e.g., ACCs) are several possible causes for the mismatches. Relative to coexisting aqueous Mg2+, we find that ACCs will enrich heavy Mg isotopes, i.e., ~1.45‰ at 25 °C, agreeing with previous experimental estimation. Equilibrium Mg isotope fractionation factors between brucite and solutions are also predicted. Besides, we applied VVCM to predict the Mg isotope fractionations between high-temperature phases, i.e., forsterite, diopside, enstatite, tremolite and spinel. The predicted β factors are in the order of spinel > tremolite > diopside > enstatite > forsterite. This study provides a base for understanding the accumulating Mg isotope data.
•Mg isotope fractionations of carbonates, ACCs and aqueous species•Mg isotope fractionation between brucite and aqueous Mg2+•An average fractionation of +1.45‰ is predicted between ACC and aqueous Mg2+.•26Mg/24Mg β values of fosterite, diopside, enstatite, spinel and tremolite
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