Effects of changing riparian topography on the decline of ecological indicators along the drawdown zones of long rivers in China

Riparian topographical features can drive a suite of ecological indicators (EIs) that shape the river ecosystem. The mechanisms that EIs reflect provide several ecosystem services. We know little about the responses of EIs (indicators of plant cover, regeneration, exotics, habitat, erosion, and stressors) to the changing stream-channel width, riparian width, and elevation of the lengthy drawdown zones (upstream, midstream, and downstream) of long rivers. We have discovered that changing topographical characteristics affect riparian buffer areas differently by using a rapid field-based method with 297 transects in inundated regions along the Yangtze River and other 36 linked tributaries in China. Changing stream-channel widths was most effective on downstream EIs and the least effective at midstream. The exotic parameters were the most affected (with a range of −0.36 < r < 0.401) by stream-channel widths, as determined using Pearson correlation (p < 0.05). In contrast, the changing riparian width had the uppermost impact on the upstream EIs and the lowermost impact downstream; riparian width had the most significant impact on habitat parameters (with r ≤ 0.787). The elevation followed the riparian width pattern and was negatively associated with habitat and exotics (r ≤ −0.645 and r ≤ −0.594) and positively correlated with regeneration (r ≤ 0.569). These results reaffirm the imperative need for studies on regionally dependent riparian areas maintained under the same management strategies regardless of their topographical features. Future policies should be formulated to enhance ecosystem service provision, promoting the sustainable use of extensive river ecosystems while considering EIs. Additionally, these future policies should acknowledge drawdown zone factors within the same river network. Furthermore, additional measures are imperative to conserve topographical features and prevent further destruction

Transfer Learning for Contextual Multi-armed Bandits

Motivated by a range of applications, we study in this paper the problem of transfer learning for nonparametric contextual multi-armed bandits under the covariate shift model, where we have data collected on source bandits before the start of the target bandit learning. The minimax rate of convergence for the cumulative regret is established and a novel transfer learning algorithm that attains the minimax regret is proposed. The results quantify the contribution of the data from the source domains for learning in the target domain in the context of nonparametric contextual multi-armed bandits. In view of the general impossibility of adaptation to unknown smoothness, we develop a data-driven algorithm that achieves near-optimal statistical guarantees (up to a logarithmic factor) while automatically adapting to the unknown parameters over a large collection of parameter spaces under an additional self-similarity assumption. A simulation study is carried out to illustrate the benefits of utilizing the data from the auxiliary source domains for learning in the target domain

Minimax Estimation of Linear Functions of Eigenvectors in the Face of Small Eigen-Gaps

Eigenvector perturbation analysis plays a vital role in various data science applications. A large body of prior works, however, focused on establishing $\ell_{2}$ eigenvector perturbation bounds, which are often highly inadequate in addressing tasks that rely on fine-grained behavior of an eigenvector. This paper makes progress on this by studying the perturbation of linear functions of an unknown eigenvector. Focusing on two fundamental problems -- matrix denoising and principal component analysis -- in the presence of Gaussian noise, we develop a suite of statistical theory that characterizes the perturbation of arbitrary linear functions of an unknown eigenvector. In order to mitigate a non-negligible bias issue inherent to the natural ``plug-in'' estimator, we develop de-biased estimators that (1) achieve minimax lower bounds for a family of scenarios (modulo some logarithmic factor), and (2) can be computed in a data-driven manner without sample splitting. Noteworthily, the proposed estimators are nearly minimax optimal even when the associated eigen-gap is {\em substantially smaller} than what is required in prior statistical theory

Artificially remediated plants impact soil physiochemical properties along the riparian zones of the three gorges dam in China

River ecosystem biodiversity and biogeochemical processes are shaped largely by riverside vegetation and soil. Moreover, river ecosystems provide ecological services influenced by the surrounding vegetation and soil interactions. However, the mechanisms by which artificially remediated plants (ARPs) and riparian soil interact to provide these benefits are still unclear among various ARPs. This study fills this gap and examines the impact of ARPs along the riparian zones of Three Gorges Dam (TGD) in Chongqing City, China. We sampled four varieties of ARPs from the Ruxi River Basin in the TGD. These varieties included Cynodon dactylon, Hemarthria altissima, Taxodium disticum, and Salix mastudana. Our results indicated substantial changes in soil physicochemical parameters. Comparably, T. distigum contains significantly higher soil chemical contents. Interestingly, principal component analysis explained almost 100% of the variance for all plant species in this study. Moreover, different vegetation types and soil chemical properties were positively correlated using Pearson correlation analysis (p < 0.05). Furthermore, all plant species exhibited strong negative correlations with physical characteristics (up to r = −1.00). Specifically, these mechanisms explain the interactions between ARPs and soil from riparian areas in the TGD. Hence, this study may facilitate ecological restoration and land management in degraded riparian areas

Nonconvex Low-Rank Tensor Completion from Noisy Data

We study a noisy tensor completion problem of broad practical interest, namely, the reconstruction of a low-rank tensor from highly incomplete and randomly corrupted observations of its entries. While a variety of prior work has been dedicated to this problem, prior algorithms either are computationally too expensive for large-scale applications, or come with sub-optimal statistical guarantees. Focusing on "incoherent" and well-conditioned tensors of a constant CP rank, we propose a two-stage nonconvex algorithm -- (vanilla) gradient descent following a rough initialization -- that achieves the best of both worlds. Specifically, the proposed nonconvex algorithm faithfully completes the tensor and retrieves all individual tensor factors within nearly linear time, while at the same time enjoying near-optimal statistical guarantees (i.e. minimal sample complexity and optimal estimation accuracy). The estimation errors are evenly spread out across all entries, thus achieving optimal $\ell_{\infty}$ statistical accuracy. We have also discussed how to extend our approach to accommodate asymmetric tensors. The insight conveyed through our analysis of nonconvex optimization might have implications for other tensor estimation problems.Comment: Accepted to Operations Researc

Anti-inflammatory effects of Fritillaria ussuriensis maxim

Bulbs of Fritillaria ussuriensis Maxim., usually known as Bulbus Fritillariae ussuriensis, (BFU) has been used as antitussive, antiasthmatic and expectorant in traditional herbal medicine. In this study, the aqueous extract of BFU (BFUE) was evaluated for its anti-inflammatory activity. Meanwhile, the content of PGE2 and MDA in inflammatory exudates was measured to explore the anti-inflammatory mechanisms of BFUE. In order to identify the active components of BFU, the total alkaloids (TA), the total flavonoids (TF) and the total saponins (TS) were evaluated for their bioactivities. Results showed that BFUE inhibited carrageenin-induced paw edema, xylene-induced auricular edema and acetic acid-induced vascular permeation in a dose-dependent manner, and it revealed obvious inhibitory effects on the increase of PGE2 and MDA. TF showed the highest anti-inflammatory effects on auricular edema induced by xylene in mice, and TS at a dose of 400 and 200 mg/kg also showed good effects (P 2 and MDA levels, and TF and TS might be the active components for this activity.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Anti-inflammatory effects of Fritillaria ussuriensis maxim

Bulbs of Fritillaria ussuriensis Maxim., usually known as Bulbus Fritillariae ussuriensis, (BFU) has been used as antitussive, antiasthmatic and expectorant in traditional herbal medicine. In this study, the aqueous extract of BFU (BFUE) was evaluated for its anti-inflammatory activity. Meanwhile, the content of PGE2 and MDA in inflammatory exudates was measured to explore the anti-inflammatory mechanisms of BFUE. In order to identify the active components of BFU, the total alkaloids (TA), the total flavonoids (TF) and the total saponins (TS) were evaluated for their bioactivities. Results showed that BFUE inhibited carrageenin-induced paw edema, xylene-induced auricular edema and acetic acid-induced vascular permeation in a dose-dependent manner, and it revealed obvious inhibitory effects on the increase of PGE2 and MDA. TF showed the highest anti-inflammatory effects on auricular edema induced by xylene in mice, and TS at a dose of 400 and 200 mg/kg also showed good effects (P 2 and MDA levels, and TF and TS might be the active components for this activity.Colegio de Farmacéuticos de la Provincia de Buenos Aire

In vitro antioxidant and in vivo anti-inflammatory potential of crude non-alkaloid fractions from fritillaria ussuriensis maxim

The present study was conducted to evaluate the antioxidant and anti-inflammatory effects of the ethanol extracts (PBE) and the non-alkaloid fractions, the crude saponin extract (CSE) and the crude flavonoids extract (CFE), of Fritillaria ussuriensis Maxim (PB). The antioxidant activity of PB extracts decreased in the order: CFE >CSE > PBE. All the administered groups produced significant anti-inflammatory effects on the three animal models. The results demonstrated that the different fractions of PB have different responses with different antioxidant methods and anti-inflammation animal models. CSE showed the best antioxidant and anti-inflammatory activities and CFE and PBE followed.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Association between Selenium Status and Chronic Kidney Disease in Middle‐Aged and Older Chinese Based on CHNS Data

Background: The association between selenium and chronic kidney disease (CKD) remains controversial. Population studies with large samples facilitate the reliability of conclusions. Objective: In this study, we aimed to describe the prevalence of a CKD association with selenium intake in middle‐aged and older Chinese. Methods: Data for this study were obtained from the China Health and Nutrition Survey (CHNS). A total of 5381 participants (aged ≥ 45) with biochem-ical test data were included in the study. Logistic regression models were used to examine the association between diet selenium intake (quartile) and the prevalence of CKD. Results: A total of 942 (17.01%) participants had CKD. The prevalence of CKD was 23.33%, 20.32%, 14.98%, and 9.25% among participants with average selenium intakes of 21.5 ± 4.82, 33.1 ± 2.79, 43.8 ± 3.70, and 67.0 ± 13.97 μg/day, respectively. In the fully adjusted model (Model 3), across the quartiles of selenium intake, the ORs for the prevalence of CKD were 1.00, 1.09 (95% CI 0.69–1.73), 0.82 (95% CI 0.49–1.38), and 0.43 (95% CI 0.22–0.85). The protein intake had a certain diagnostic significance for the selenium intake. Conclusions: An adequate selenium intake may have a positive effect on CKD. The influence of individual weight and location on the effect of selenium on CKD needs to be further explored.This work was supported by a project of the Chongqing Nutrition Society (2019001): Research on dietary selenium intake and its relationship with hypertension and diabetes in middle-aged and older adults in Jiangjin Chongqing. Yong Zhao received research support from the Chongqing Nutrition Society. This research used data from the China Health and Nutrition Survey (CHNS). Manythanks to the National Institute for Nutrition and Health, China Center for Disease Control and Prevention, the Carolina Population Center (P2C HD050924, T32 HD007168), the University of North Carolina at Chapel Hill, the NIH (R01-HD30880, DK056350, R24 HD050924, and R01-HD38700), and the NIH Fogarty International Center (D43 TW009077, D43 TW007709)

Selenium Intake and its Interaction with Iron Intake Are Associated with Cognitive Functions in Chinese Adults: A Longitudinal Study

Studies on the relation between selenium intake and cognitive function are inconclusive. This study aimed to examine the associations between dietary selenium intake and cognitive function among Chinese adults and tested the interaction effect of selenium intake and iron intake on cognition. Data from 4852 adults aged 55 years and above who attended the 1991–2006 China Health and Nutrition Survey (CHNS) were used. Cognitive function was assessed through face-to-face interviews in 1997, 2000, 2004, and 2006. A 3-day, 24-hour recall was used to collect dietary selenium intake. Multivariable mixed linear regression and logistic regression were used in the analyses. In fully adjusted regression models, the regression coefficients (95% confidence interval) were 0.00, 0.29 (−0.12–0.70), 0.26 (−0.18–0.70), and 0.50 (0.02–0.97) across the quartiles of selenium intake. In the subgroup analysis, the positive association between selenium intake and cognitive function was only observed in the participants who live in the southern region but not those in the northern region. The selenium-intake-to-iron-intake ratio was inversely associated with low global cognition scores. Furthermore, only those with a normal BMI had a positive association between selenium and cognition. In conclusion, high selenium intake was linked to better cognitive function and a lower risk of cognition decline in Chinese adults among those with low iron intake. A substantial interaction was found between selenium intake and BMI or region.Thisproject wasfundedbytheprojectofChongqingNutritionSociety(2019001)-Research on dietary selenium intake and its relationship with hypertension and diabetes in middle-aged and older adults in Jiangjin Chongqing. Thefundershadnoroleinthedesign, analysis, datainterpretation, and publication of the findings