Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

The Measurement of Capital Stock of China

Capital stock is an important indicator in economics, it is an important indicator to measure the social and economic development status. But the research of capital stock is not wildly contributed. This paper is to measure capital stock and forecast future capital stock with time series models. The author conducts empirical methods based on the measurement methods of previous scholars. The paper concludes that the capital stock is growing stably, and with established new mathematical models and time series models, and combined with the latest data, measures the capital stock of China

Mutual influences and trends of Global Economic Growth and Global Mergers and Acquisitions

The paper is to analyze the relationship between Global Economic Growth and Global Mergers and Acquisitions. After applying empirical analysis, conclude that Global Economic Growth and Global Mergers and Acquisitions have mutual influences on each other in the long-term period. In the short-term period, the results show the same trend. But in some short certain periods like rapid economic recessions, the trend shows the other way around. The paper also analyzes the economic intuitions of the mutual influences

NH4Cl-assisted preparation of single Ni sites anchored carbon nanosheet catalysts for highly efficient carbon dioxide electroreduction

Single-atomic transition metal-nitrogen codoped carbon (M-N-C) are efficient substitute catalysts for noble metals to catalyze electrochemical CO2 reduction reaction. However, the uncontrolled aggregations of metal and serious loss of nitrogen species constituting the M-Nx active sites are frequently observed in the commonly used pyrolysis procedure. Herein, single-atomic nickel (Ni)-based sheet-like electrocatalysts with abundant Ni-N4 active sites were created by using a novel ammonium chloride (NH4Cl)-assited pyrolysis method. Spherical aberration correction electron microscopy and X-ray absorption fine structure analysis clearly revealed that Ni species are atomically dispersed and anchored by N in Ni-N4 structure. The addition of ammonium chloride (NH4Cl) optimized the mesopore size to 7-10 nm, and increased the concentrations of pyridinic N (3.54 wt) and Ni-N4 (3.33 wt) species. The synergistic catalytic effect derived from Ni-N4 active sites and pyridinic N species achieved an outstanding CO2RR performance, presenting a high CO Faradaic efficiency (FECO) up to 98 and a large CO partial current density of 8.5 mA·cm−2 at a low potential of -0.62 V vs. RHE. Particularly, the FECO maintains above 80 within a large potential range from -0.43 to -0.73 V vs. RHE. This work provides a practical and feasible approach to build highly active single-atomic catalysts for CO2 conversion systems