The present study, seasonal pollution of heavy metals (Pb, Cd, Cr and Cu) in water, sediment, tissues of fish Carassius carassius and oyster Crassostrea gigas were determined at seven sampling sites ...from Meiliang Bay, Taihu Lake during one year calendar, 2016. The total heavy metal concentrations in water samples were higher in winter and summer than in spring and autumn season, whereas in sediment they were higher in winter and summer seasons, respectively. The trend of metal mean contents found in the fish and oyster were in decreasing order of Pb > Cu > Cr > Cd and Pb > Cu > Cr > Cd, respectively. The tissues of fish and oyster captured during winter and summer accumulated a higher significant different amount of metals relative to other season, which was attributed to a higher influx of agricultural waste, sewage and sludge by heavy rainfall and floods. In addition, the pollution load index (PLI) values were above one (>1), indicating an advanced decline of the sediment quality, and contamination factor (CF) confirmed that the sediment samples were moderate to high contamination by Pb and Cr. Thus, comparative studies with seasonal pollution of heavy metals in Meiliang Bay of Lake Taihu regions indicate considerable heavy metal enrichment in water, sediments as well as in various organs of fish and oyster. Finally, our results indicated that the metal concentration values increased statistically significant different related to season (p < 0.001). The determination of heavy metal stress biomarkers in fish along with seasonal variations may serve as a convenient approach during pollution bio-monitoring programme.
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•Pb content in the water of Lake Taihu exceeded international safety thresholds.•High levels of Cr, Pb and Cu were found in sediment from Lake Taihu.•The seasonal metal accumulation pattern was mainly associated with fish and oyster.•Pb, Cr, Cu and Cd mainly originate from anthropogenic sources.
Under the long-term effect of mineral resource exploitation, especially open-pit mining, ecosystems are severely disturbed. Constructing and optimizing urban ecological networks influenced by ...open-pit mines based on mine–city coordination helps integrate ecological restoration and the construction of urban ecological environments. We applied an InVEST model to Fushun City to evaluate urban ecosystem services under the influence of large open-pit mines. Twenty-one key patches important for maintaining landscape connectivity were screened as the ecological sources in the network, from which ecological resistance surfaces were constructed by combining the impacts of mines on the environment. Minimum cumulative resistance (MCR) and gravity models were then used to extract and classify ecological corridors favorable to species migration and diffusion. Fushun City had large spatial differences in ecosystem service functions, with high-value areas concentrated in the forest-rich Dongzhou District and the northern Shuncheng District. Under the influence of open-pit mining, the ecosystem service capacity of the region south of the Hunhe River was poor and lacked ecological sources. Urban ecological resistance surfaces reached a maximum in the open-pit mining area, and 210 ecological corridors were estimated using the MCR model, of which 46 were important. Only two corridors crossed the West and East open pit, forming two “ecological fracture surfaces.” The Dongzhou and eastern Shuncheng districts had complex network structures and stable ecological environments. In contrast, the central and southern parts of Fushun City lacked ecological corridors owing to the influence of mining pits and gangue mountains, had simple network structures, and low connectivities with other sources. Combined with Fushun City’s development plan, we propose that ecological network optimization should add new ecological source sites, reconstruct and repair ecological corridors, and upgrade ecological breakpoints. This study provides reference and basis for ecological network research in mining cities influenced by open-pit mines.
Organisms exist within ecological networks, connected through interactions such as parasitism, predation and mutualism which can modify their abundance and distribution within habitat patches. ...Differential species responses make it hard to predict the influence of climate change at the community scale. Understanding the interplay between climate and biotic interactions can improve our predictions of how ecosystems will respond to current global warming.
We aim to understand how climate affects the multitrophic biotic interactions as well as the community structure using the enclosed communities of wasps associated with figs as study system.
To examine the presence and strength of multitrophic species interactions, we first characterized the multitrophic community of fig wasps associated with Ficus racemosa and then applied hierarchical joint species distribution models, fitted to community monitoring data. We further evaluated the effect of climate on individual species trends as well as interspecific interactions.
We found that the competitive balance shifted to favour non‐pollinating galling wasps and disadvantage the dominant pollinator in suboptimal conditions. Furthermore, suboptimal conditions for galling wasps facilitated the occurrence of their specialized parasitoid, as changes cascaded across trophic levels and led to alternative community structures. Our results highlight the role of how species interactions can be modified across multiple trophic levels in a fig wasp community according to climate.
摘要
生态系统中的各类生物通过寄生、捕食、互惠等相互作用组成生态网络，并相互影响与制约。由于不同物种外界变化的响应存在差异，在群落水平上预测气候变化对生物的影响一直是个难点。了解气候与物种间相互作用怎样共同作用于群落中的物种，有助于完善生态系统如何响应当前气候变暖的预测。
在该研究中，我们选用榕小蜂群落作为研究系统，目标揭示气候怎样影响多营养级生物互作体及其群落结构。
我们首先通过应用层级联合物种分布模型 (Hierarchical joint species distribution models) 分析了群落监测数据，检测了聚果榕多营养级榕小蜂群落多种种间互作的关系与强度。再进一步评估气候对单个物种动态及种间互作的影响。
研究发现:当处于非最佳气候条件时，同一营养级之间的种间竞争更倾向于非优势的非传粉造瘿小蜂，对优势的传粉榕小蜂不利；而且同一营养级之间竞争平衡的倾斜，通过跨营养级的级联效应促进了非传粉造瘿小蜂专性复寄生蜂的发生，从而导致群落结构的改变。结果强调了气候通过级联效应影响种间的不同互作关系，最终影响多营养级的榕小蜂群落。
By investigating the responses of fig wasp species to temperature shifts, this study highlights the central role of biotic interactions in determining the impact of climate on ecological communities.
We conducted the first profitability comparison study across health care industries in the United States, using the DuPont Analysis framework. The combination of Return on Equity (ROE) and ROE ...volatility was used to provide a comprehensive “risk-return” approach for profitability comparison. Based on the 2010–2019 financial disclosures of 1,231 publicly traded health care companies in the U.S. that reported positive assets and equity, we estimated the industry-specific fixed effects on ROE and its three components—profit margin, asset utilization, and financial leverage—for ten industries in the health care sector, classified by the Global Industry Classification Standard (GICS). For each industry, we also estimated its fixed effects on ROE volatility. We found that the pharmaceuticals industry and biotechnology industry have lower ROE—mainly driven by their relatively low profit margin and low assets utilization—and higher ROE volatility than other health care industries. We also found that the health care facilities industry relies most on debt financing. This study demonstrates a holistic approach for profitability comparison across industries.
Hepatic ischemia-reperfusion (I/R) injury is inevitable during hepatectomy and may cause both postoperative morbidity and mortality. Regenerative medicine suggested adipose-derived stem cells (ADSCs) ...as an attractive tool for the treatment of liver diseases. In this study, we investigated the effect of ADSCs in an I/R model combined with laparoscopic hepatectomy in swine. Eighteen Bama miniature pigs were randomly divided into Sham, IRI, and ADSCs groups. ADSCs (1 × 10
/kg) were injected through liver parenchyma immediately after hemihepatectomy. The apoptosis-related role of ADSCs was studied. The results showed that ADSCs transplantation reduced both pathological and ultrastructural changes and decreased the number of apoptotic-positive cells. In the ADSCs group, Fas, Fas ligand (FasL) protein, and mRNA were downregulated and the enzyme activities of Caspase3, Caspase8, and Caspase9 were significantly decreased. In addition, ADSC therapy significantly increased the ratio of Bcl-2/Bax protein and mRNA compared to the IRI group. In conclusion, ADSCs attenuated both I/R and hepatectomy-induced liver apoptosis in a porcine model, and offers a potential therapeutic option for hepatic I/R and hepatectomy.
Hospitals acquire and maintain long-term operating assets such as land, buildings, and equipment. In this study, we analyzed hospitals’ long-term assets acquisitions data extracted from the Medicare ...Cost Report, a mandatory annual filing for all Medicare-certified hospitals. The first objective of this study is to examine the time trend of land, buildings, and equipment acquisitions of all general acute care hospitals in the U.S. from 2005 to 2019 to understand the relative magnitude and temporal changes for the operating assets. The second objective is to examine the 15-year accumulated acquisitions of land, buildings, and equipment per capita in each state to understand the variations of potential access to hospital operating resources across states. To understand the longitudinal changes in acquisitions of operating assets for each year from 2005 to 2019, we calculated the total acquisition amounts across all hospitals for land, buildings, and equipment, respectively, and adjusted the amounts to 2019 dollars based on the consumer price index (CPI). For each state (including Washington D.C.) and the whole nation, the 15-year accumulated CPI-adjusted acquisition amounts per capita for land, buildings, and equipment were also calculated, respectively. The nationwide acquisitions of those operating assets grew rapidly from 2005 to 2008 followed by a negative overall growth from 2008 to 2014 and since 2015, started increasing steadily again. In 2019, U.S. general acute care hospitals acquired $3.0 billion of land, $44.6 billion of buildings, and $33.9 billion of equipment. Huge geographical variation in per capita cumulative total asset investment were also found with the first place North Dakota having a per capita investment that is almost four times higher than that in the lowest ranked state of Alabama.
This study examined if greater insurer market power was associated with consistently lower negotiated prices within each hospital for 44 shoppable and emergency procedures, using price transparency ...data disclosed by 1,506 hospitals in metropolitan areas. We used multi-level fixed effects models to estimate the within-hospital variation in plan-level insurer-negotiated prices (from the largest insurer, the second largest insurer, other major insurers, and nonmajor insurers) and cash-pay prices as a function of insurer market power. For shoppable services, relative to nonmajor insurers, the largest, second largest, and other major insurers negotiated 23%, 16%, and 3% lower prices, respectively, while cash prices were 17% higher. For emergency room visits, while the largest insurers paid 5% less than nonmajor insurers, the second largest and other major insurers did not pay lower prices. Stratified analyses by type of shoppable services found varying magnitudes and patterns of price discounts associated with insurer market power.
The traditional optical fiber-based twist sensing has the disadvantage of low sensitivity and difficulty of distinguishing the twist direction. Moreover, chiral isomerism may lead to sensing errors. ...In this paper, a six-hole helical microstructured optical fiber (HMSF) with a thin-gold-film-coat based on the surface plasmon resonance (SPR) effect was designed. The twist sensing characteristics of this fiber were further analyzed. Numerical calculation and analysis show that the combination of helical effect and SPR effect can design an HMSF-based sensor that is very sensitive to distortion. In the torsion range of ±300°, the distortion sensitivity can reach 2470.7 pm/(rad/m), and the linear correlation coefficient is 0.99996. Based on the special sensing mechanism, it has a good linear coefficient over a large range. Additionally, the direction of the twist can be easily discerned. The HMSF in this work not only has high sensitivity, high linearity, high fault tolerance rate, and a wide range of measurement, but is also easy to manufacture. Therefore, it is promising in the field of twist sensing and has a good application prospect.
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