Estuarine delta is a critical zone for a series of biogeochemical processes including greenhouse gas emissions, organic matter transport and burial. These processes are mainly mediated by microbial ...activities such as heterotroph, methanogenesis, and methanotroph. However, response of microbial activities in the delta to paleoenvironmental change is less constrained. In this study, we analyzed the concentrations and compositions of microbial ether lipids (branched GDGTs and isoprenoid GDGTs) in a core from the Liaohe Delta, the northeast China, to explore the response of bacteria and archaea communities to climate change since 32 ka BP. During the glacial periods, the concentrations of branched GDGTs and isoprenoid GDGTs were low possibly due to the low temperature inhibiting the growth of microorganisms. After the Last Glacial Maximum (LGM), the abundance of GDGT concentrations increased, and reached the maximum during the Bølling/Allerød (B/A) period, then decreased during the Younger Dryas (YD) and increased again during the early Holocene. This pattern indicated that the abundance of the microorganisms in the Liaohe Delta was mainly controlled by temperature since 32 ka BP. In addition to temperature, sea level fluctuation and local hydrological disturbance may also effect microbial growth in the Liaohe Delta. Significant increase in the ratio of GDGT-0 versus crenarchaeol (R0/5) indicates that the rise of lake level provided a favorable anaerobic environment for methanogen blooming during the B/A and the early Holocene. Low lake level and strong water mixing made oxygen content increase, thus inhibited methanogen growth and further led to the decrease of the R0/5 values in the YD, suggesting that methanogenesis in global estuaries may impact atmospheric methane content. Our results provide a means to interpret response of microbial abundance and biogeochemical processes to paleoclimate change since the Last Glacial Maximum in estuarine delta.
•The microbial abundance is closely related to temperature in LHD since 32 ka BP.•The methanogenetic processes in coastal wetland play an important role in atmospheric methane cycle.•GDGTs were invistigated in a sedimentary core collected from Liaohe Delta.
IntroductionLeg ulcers (LUs) not only seriously affect life and work of patients, but also bring huge economic burden to the society. As a potential underused biological debridement, larval therapy ...provides help for the treatment of LUs. The purpose of our research is to assess whether patients with LUs can benefit from larval therapy.Methods and analysisThe following electronic databases will be searched: PubMed, EMBASE, Web of Science, the Cochrane Library, China National Knowledge Infrastructure Database, Wanfang Database and Chinese Biological Medicine. Randomised controlled trials are eligible for inclusion. There will be no restrictions with respect to language and search date is up to June 2020. Primary outcomes investigated are complete healing rate after treatment, time to ulcer healing, reduction of wound surface area and adverse events. Risk ratios will be used for categorical data; weighted mean difference will be used for measurement data. Subgroup analysis and sensitivity analysis will be considered if heterogeneity exists. The results of data synthesis will be performed by narrative summary and quantitative analysis.Ethics and disseminationThis systematic review does not require the approval of the ethics committee because individual data on patients are not collected. The results of the study will be disseminated in peer-reviewed journals.PROSPERO registration numberCRD42020176953.
How Valuable Is FinTech Innovation? Chen, Mark A.; Wu, Qinxi; Yang, Baozhong
The Review of financial studies,
05/2019, Letnik:
32, Številka:
5
Journal Article
Recenzirano
Odprti dostop
We provide large-scale evidence on the occurrence and value of FinTech innovation. Using data on patent filings from 2003 to 2017, we apply machine learning to identify and classify innovations by ...their underlying technologies. We find that most FinTech innovations yield substantial value to innovators, with blockchain being particularly valuable. For the overall financial sector, internet of things (IoT), robo-advising, and blockchain are the most valuable innovation types. Innovations affect financial industries more negatively when they involve disruptive technologies from nonfinancial startups, but market leaders that invest heavily in their own innovation can avoid much of the negative value effect.
The mystery of zero-leverage firms Strebulaev, Ilya A.; Yang, Baozhong
Journal of financial economics,
07/2013, Letnik:
109, Številka:
1
Journal Article
Recenzirano
Odprti dostop
We present the puzzling evidence that, from 1962 to 2009, an average 10.2% of large public nonfinancial US firms have zero debt and almost 22% have less than 5% book leverage ratio. Zero-leverage ...behavior is a persistent phenomenon. Dividend-paying zero-leverage firms pay substantially higher dividends, are more profitable, pay higher taxes, issue less equity, and have higher cash balances than control firms chosen by industry and size. Firms with higher Chief Executive Officer (CEO) ownership and longer CEO tenure are more likely to have zero debt, especially if boards are smaller and less independent. Family firms are also more likely to be zero-levered.
Background:
Several paclitaxel-coated balloons have been proved to provide better efficacy results than uncoated balloons in femoropopliteal lesions. But the efficacy and safety of FREEWAY balloons ...have not been investigated in Chinese patients. This study aimed to evaluate the efficacy and safety performance of FREEWAY paclitaxel-coated balloons vs. uncoated balloons in Chinese femoropopliteal artery lesions.
Methods:
In this prospective multi-center randomized controlled FREEWAY-CHINA study, 311 patients with symptomatic lower limb ischemia (Rutherford category 2–5) and femoropopliteal lesions of 14 Chinese centers were randomly assigned in a 1:1 ratio to endovascular treatment with either FREEWAY paclitaxel-coated balloons or uncoated balloons (control). The primary endpoint was the 6-month clinically-driven target lesion revascularization (CD-TLR) rate. Secondary endpoints included the device and technical success rate, the ankle-brachial indexes (ABIs), Rutherford category change, the 6-month primary and secondary patency rates, severe adverse effects, and the 12-month CD-TLR rate.
Results:
The two groups were comparable in terms of their demographic and lesion characteristics. Patients' mean age was 70 years, and 70% were men. The mean lesion length was 71 mm. The 6-month CD-TLR rate was 2.6% in the FREEWAY group and 11.7% in the control group (
P
= 0.001). The 12-month CD-TLR rate was 2.7% in the FREEWAY group and 13.2% in the control group (
P
= 0.0005). Other endpoints, including patency rates, major adverse events, and ABI or Rutherford change, did not differ between the two groups.
Conclusion:
The FREEWAY balloon resulted in an effective decrease in CD-TLR rates and had similar safety results compared to the uncoated balloon in Chinese femoropopliteal artery patients at the 12-month follow-up appointment.
This paper builds a dynamic trade-off model of corporate financing with differences in belief between the insider manager and outside investors. The optimal leverage depends on differences of opinion ...and can differ significantly from that in standard trade-off models. The manager's market timing behavior leads to several stylized facts, such as the low average debt ratios of firms in the cross section, the substantial presence of zero-debt firms that pay larger dividends and keep higher cash balances than other firms, and negative long-run abnormal returns following stock issuance. Market timing behavior leads to substantial losses of firm value through excessive financing activities. Market timing and debt conservatism depend negatively on shareholder control of the firm.
•Optimal leverage depends on differences of opinion between insider and outsiders.•Low leverage and substantial presence of zero-debt firms.•Negative long-run abnormal returns following stock issuance.•Substantial losses of firm value through market timing and excessive financing.•Market timing depends negatively on shareholder control.
This paper studies the "confidential holdings" of institutional investors, especially hedge funds, where the quarter-end equity holdings are disclosed with a delay through amendments to Form 13F and ...are usually excluded from the standard databases. Funds managing large risky portfolios with nonconventional strategies seek confidentiality more frequently. Stocks in these holdings are disproportionately associated with information-sensitive events or share characteristics indicating greater information asymmetry. Confidential holdings exhibit superior performance up to 12 months, and tend to take longer to build. Together the evidence supports private information and the associated price impact as the dominant motives for confidentiality.
We study investor communication and stock comovement using a novel data set from an active online stock forum in China. We find substantial comovement among the returns of a stock and its "related ...stocks," which are frequently discussed in the subforum dedicated to the given stock. Comovement is greater when the discussion of related stocks is more intensive. Further, the effect of communication on comovement is stronger for stocks associated with higher information uncertainty. Codiscussed stocks are more actively traded and experience more correlated trading. A trading strategy that exploits communication-driven comovement generates abnormal returns. Our findings highlight the impact of investor communication on asset comovement.
We examine the impact of mandatory portfolio disclosure by mutual funds on stock liquidity and fund performance. We develop a model of informed trading with disclosure and test its predictions using ...the May 2004 SEC regulation requiring more frequent disclosure. Stocks with higher fund ownership, especially those held by more informed funds or subject to greater information asymmetry, experience larger increases in liquidity after the regulation change. More informed funds, especially those holding stocks with greater information asymmetry, experience greater performance deterioration after the regulation change. Overall, mandatory disclosure improves stock liquidity but imposes costs on informed investors.
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