Satellite mapping in cities and below cities: how good is it now?

Global navigation satellite systems (GNSS) have existed since the launch of the US global positioning system constellation in 1978. There is an increasing need for better maps in the digital age, particularly for buried utilities. One of the most convenient methods for creating accurate maps is the use of navigation satellites for positioning. However, built-up urban areas are not ideal for the use of this positioning technology. This paper provides an update on the situation regarding GNSS and assesses how new satellites and signals are contributing to better positioning availability by carrying out a test in a controlled environment. The results show that using combined satellite systems improves availability in urban canyons in some cases, but not in all scenarios. In addition, pipeline mapping technology has been tested and been shown to be an effective means of mapping pipes deep under the ground over short distances

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

Boron-doped diamond semiconductor electrodes: Efficient photoelectrochemical CO2 reduction through surface modification

Competitive hydrogen evolution and multiple proton-coupled electron transfer reactions limit photoelectrochemical CO(2) reduction in aqueous electrolyte. Here, oxygen-terminated lightly boron-doped diamond (BDD(L)) thin films were synthesized as a semiconductor electron source to accelerate CO(2) reduction. However, BDD(L) alone could not stabilize the intermediates of CO(2) reduction, yielding a negligible amount of reduction products. Silver nanoparticles were then deposited on BDD(L) because of their selective electrochemical CO(2) reduction ability. Excellent selectivity (estimated CO:H(2) mass ratio of 318:1) and recyclability (stable for five cycles of 3 h each) for photoelectrochemical CO(2) reduction were obtained for the optimum silver nanoparticle-modified BDD(L) electrode at −1.1 V vs. RHE under 222-nm irradiation. The high efficiency and stability of this catalyst are ascribed to the in situ photoactivation of the BDD(L) surface during the photoelectrochemical reaction. The present work reveals the potential of BDD(L) as a high-energy electron source for use with co-catalysts in photochemical conversion

Open letter to the members of the GOLD committee

OPEN LETTER: This letter arises from discussions and correspondence between colleagues involved in respiratory research or the diagnosis and treatment of lung diseases, as well as from a review of the literature on COPD. As discussed below, it is written in the hope that we can persuade members of the GOLD committee to vote to change the method by which mild airway obstruction is defined by the GOLD guidelines