Photon-avalanche upconversion of red light into blue light in a thulium-doped fluorozirconate fibre

We report the investigation of the photon-avalanche effect in heavily thulium-doped fluorozirconate fibre. Pumping at red wavelengths, which are not resonant with the ground-state absorption, gives blue emission at 450nm and 480nm

Blue avalanche upconversion in Tm:ZBLAN fibre

We report the investigation of the photon avalanche effect in heavily doped Tm:ZBLAN fibre at room temperature. Pumping at 630nm to 650nm, which is not resonant with the ground state absorption, gives intense blue emissions at 450nm and 480nm. The time evolution of the absorption and emission show a slow decaying oscillation before steady state is reached

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

Cohort Profile: Pregnancy And Childhood Epigenetics (PACE) Consortium.

Development Psychopathology in context: famil

The MeerKAT Galaxy Cluster Legacy Survey: I. Survey overview and highlights

Please abstract in the article.The South African Radio Astronomy Observatory (SARAO), the National Research Foundation (NRF), the National Radio Astronomy Observatory, US National Science Foundation, the South African Research Chairs Initiative of the DSI/NRF, the SARAO HCD programme, the South African Research Chairs Initiative of the Department of Science and Innovation.http://www.aanda.orghj2022Physic

Upconversion Phenomena in Nanofluorides

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Infrared to green up-conversion in LaCl3_3:U3+^{3+}

Investigations of the optical properties of LaCl/sub 3/:U/sup 3+/ (0.1%) single crystal have revealed an interesting up-conversion phenomenon. When the /sup 4/G/sub 7/2/ level of U/sup 3+/ is excited by an infrared laser set at 748.6 nm, a strong green fluorescence from the /sup 2/K/sub 15/2/ level is observed. From the analysis of the dynamics of the excited states, we conclude that the observed phenomenon occurs mainly via two mechanisms: (i) excited-state absorption and (ii) an energy transfer up-conversion (ETU) process involving pairs of U/sup 3+/ ions in /sup 4/G/sub 5/2/ and /sup 4/F/sub 9/2/ states

Upconversion Phenomena in Nanofluorides

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RELAXATION OF HIGH LYING EXCITED STATES OF Nd3+ IONS IN YAG : Nd3+ AND IN YAP : Nd3+

After selective excitation in either the 2P3/2 or the 4D3/2 multiplet of Nd3+ in YAG or in YAP, the fluorescence properties of these levels are analysed. The YAG:Nd3+ sample exhibits a very strong visible fluorescence attributed to transitions from the 2F(2)5/2 multiplet as a consequence of a very efficient excited state absorption mechanism from the 2P3/2 métastable state