Raman and Luminescence Investigation of Rare Earth Doped Ferroelectric Crystals and Laser-Induced Crystals-in-Glass

Rare earth-doped ferroelectric crystals are an interesting and important class of materials due to their wide array of favorable properties. These properties make them attractive for many different applications. However, as smaller, better-performing devices are sought after, novel processes for engineering optical materials must be developed and understood. Additionally, the response of the desirable properties to a reduction in size, and to the fabrication techniques, must be quantified and controlled. This work is aimed at advancing the understanding of two of these materials, namely lithium niobate (LiNbO3) and lanthanum borogermanate (LaBGeO5), and their properties via the development and utilization of multifaceted measurement techniques. In LiNbO3, Raman spectra collected continuously during application of an external electric field reveal two different effects: (1) the energies of the Raman modes shift linearly in response to the electric field because of the distortion of the crystal via the piezoelectric effect and (2) the zero-field frequencies of the Raman modes are shifted following ferroelectric domain inversion. The former effect may be used as a calibration in order to quantify different phenomenon which produce internal electric fields. The latter effect is due to the presence of polar defects whose dipole moment does not flip during domain inversion. Using effect (1) to quantify effect (2) forces the conclusion that additional polar defects with dipole moment components orthogonal to the spontaneous polarization must exist. This finding has important consequences for the understanding of domain inversion. In a separate set of experiments, space charge fields were produced in \lin{} by laser-induced photoionization of defects at low temperature, and observed via energy shifts of both Raman modes and the erbium fluorescence emission. Occasional electrical breakdown resulted in discharging of these space charge fields. These breakdowns are seemingly random and occur inconsistently, and therefore multiple parameters were investigated in order to determine those responsible.In LaBGeO5, low temperature Combined Excitation Emission Spectroscopy (CEES) revealed that erbium incorporates into both glass-ceramics and laser-induced crystals-in-glass in predominantly one type of environment (site). However, other minority sites were also observed. The energy levels of the primary site were quantified. The fluorescence characteristics of the erbium ions in any site in the laser-induced crystals were found to be only weakly influenced by the irradiation conditions during growth. On the other hand, a hidden parameter, potentially boron deficiency-related defects, resulted in a significant change of the relative numbers of erbium ions incorporating at the minority sites compared to at the primary site. Scanning confocal Raman spectroscopy showed that the energies of the Raman modes are shifted across the cross-sections of laser-induced crystals in glass. The source of these shifts is potentially strain due the sharp temperature gradient during the laser-induced crystallization process. Fluorescence spectra collected simultaneously with Raman spectra, which for erbium is possible using a single fixed-wavelength excitation source with a wavelength of 488nm, showed that the erbium fluorescence intensity is inhomogeneous over the crystal cross-section, despite the host glass being homogeneously doped. These fluctuations were spatially correlated with small shifts in the Raman spectra, which implies that changes to the structure shift the absorption peaks of the erbium sites either toward or away from the energy of the probe laser. Finally, Raman and fluorescence spectra from laser-induced crystals in a LaBGeO5 glass prepared prior to this work exhibited anomalous behavior, including evidence of strong elemental diffusion at the center of the crystal cross-section which resulted in the crystallization of an unknown LaBGeO5 subphas

Spectroscopic Properties of Sm3+-Doped Lanthanum Borogermanate Glass

Ultraviolet–visible–near infrared (UV–vis–NIR) absorption and photoluminescence of (25-x) La2O3–25B2O3–50GeO2 glass series have been studied with different concentrations (x=0.1–1.0 wt%) of Sm2O3 as an optically active dopant. The values of Judd–Ofelt (JO) parameters (Ot) follow the trend O2>O4>O6. Visible emission and decay times from the 4G5/2 level and its relative quantum efficiencies are measured. Intense reddish-orange emission corresponding to 4G5/2?6H7/2 transition has been observed in these glasses under 488 nm excitation. A decrease in the quantum yield is observed with increasing Sm3+ ion concentration beyond 1% doping level

Effect of Bamlanivimab vs Placebo on Incidence of COVID-19 Among Residents and Staff of Skilled Nursing and Assisted Living Facilities: A Randomized Clinical Trial

IMPORTANCE Preventive interventions are needed to protect residents and staff of skilled nursing and assisted living facilities from COVID-19 during outbreaks in their facilities. Bamlanivimab, a neutralizing monoclonal antibody against SARS-CoV-2, may confer rapid protection from SARS-CoV-2 infection and COVID-19. OBJECTIVE To determine the effect of bamlanivimab on the incidence of COVID-19 among residents and staff of skilled nursing and assisted living facilities. DESIGN, SETTING, AND PARTICIPANTS Randomized, double-blind, single-dose, phase 3 trial that enrolled residents and staff of 74 skilled nursing and assisted living facilities in the United States with at least 1 confirmed SARS-CoV-2 index case. A total of 1175 participants enrolled in the study from August 2 to November 20, 2020. Database lock was triggered on January 13, 2021, when all participants reached study day 57. INTERVENTIONS Participants were randomized to receive a single intravenous infusion of bamlanivimab, 4200mg (n = 588), or placebo (n = 587). MAIN OUTCOMES AND MEASURES The primary outcomewas incidence of COVID-19, defined as the detection of SARS-CoV-2 by reverse transcriptase–polymerase chain reaction and mild or worse disease severity within 21 days of detection, within 8 weeks of randomization. Key secondary outcomes included incidence of moderate or worse COVID-19 severity and incidence of SARS-CoV-2 infection. RESULTS The prevention population comprised a total of 966 participants (666 staff and 300 residents) who were negative at baseline for SARS-CoV-2 infection and serology (mean age, 53.0 [range, 18-104] years; 722 [74.7%] women). Bamlanivimab significantly reduced the incidence of COVID-19 in the prevention population compared with placebo (8.5%vs 15.2%; odds ratio, 0.43 [95%CI, 0.28-0.68]; P < .001; absolute risk difference, −6.6 [95%CI, −10.7 to −2.6] percentage points). Five deaths attributed to COVID-19 were reported by day 57; all occurred in the placebo group. Among 1175 participants who received study product (safety population), the rate of participants with adverse events was 20.1% in the bamlanivimab group and 18.9% in the placebo group. The most common adverse events were urinary tract infection (reported by 12 participants [2%] who received bamlanivimab and 14 [2.4%] who received placebo) and hypertension (reported by 7 participants [1.2%] who received bamlanivimab and 10 [1.7%] who received placebo). CONCLUSIONS AND RELEVANCE Among residents and staff in skilled nursing and assisted living facilities, treatment during August-November 2020 with bamlanivimab monotherapy reduced the incidence of COVID-19 infection. Further research is needed to assess preventive efficacy with current patterns of viral strains with combination monoclonal antibody therapy

Hidden in the Middle : Culture, Value and Reward in Bioinformatics

Bioinformatics - the so-called shotgun marriage between biology and computer science - is an interdiscipline. Despite interdisciplinarity being seen as a virtue, for having the capacity to solve complex problems and foster innovation, it has the potential to place projects and people in anomalous categories. For example, valorised 'outputs' in academia are often defined and rewarded by discipline. Bioinformatics, as an interdisciplinary bricolage, incorporates experts from various disciplinary cultures with their own distinct ways of working. Perceived problems of interdisciplinarity include difficulties of making explicit knowledge that is practical, theoretical, or cognitive. But successful interdisciplinary research also depends on an understanding of disciplinary cultures and value systems, often only tacitly understood by members of the communities in question. In bioinformatics, the 'parent' disciplines have different value systems; for example, what is considered worthwhile research by computer scientists can be thought of as trivial by biologists, and vice versa. This paper concentrates on the problems of reward and recognition described by scientists working in academic bioinformatics in the United Kingdom. We highlight problems that are a consequence of its cross-cultural make-up, recognising that the mismatches in knowledge in this borderland take place not just at the level of the practical, theoretical, or epistemological, but also at the cultural level too. The trend in big, interdisciplinary science is towards multiple authors on a single paper; in bioinformatics this has created hybrid or fractional scientists who find they are being positioned not just in-between established disciplines but also in-between as middle authors or, worse still, left off papers altogether

Variation in carbon and nitrogen concentrations among peatland categories at the global scale

Publisher Copyright: © 2022 This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.Peatlands account for 15 to 30% of the world's soil carbon (C) stock and are important controls over global nitrogen (N) cycles. However, C and N concentrations are known to vary among peatlands contributing to the uncertainty of global C inventories, but there are few global studies that relate peatland classification to peat chemistry. We analyzed 436 peat cores sampled in 24 countries across six continents and measured C, N, and organic matter (OM) content at three depths down to 70 cm. Sites were distinguished between northern (387) and tropical (49) peatlands and assigned to one of six distinct broadly recognized peatland categories that vary primarily along a pH gradient. Peat C and N concentrations, OM content, and C:N ratios differed significantly among peatland categories, but few differences in chemistry with depth were found within each category. Across all peatlands C and N concentrations in the 10-20 cm layer, were 440 ± 85.1 g kg-1 and 13.9 ± 7.4 g kg-1, with an average C:N ratio of 30.1 ± 20.8. Among peatland categories, median C concentrations were highest in bogs, poor fens and tropical swamps (446-532 g kg-1) and lowest in intermediate and extremely rich fens (375-414 g kg-1). The C:OM ratio in peat was similar across most peatland categories, except in deeper samples from ombrotrophic tropical peat swamps that were higher than other peatlands categories. Peat N concentrations and C:N ratios varied approximately two-fold among peatland categories and N concentrations tended to be higher (and C:N lower) in intermediate fens compared with other peatland types. This study reports on a unique data set and demonstrates that differences in peat C and OM concentrations among broadly classified peatland categories are predictable, which can aid future studies that use land cover assessments to refine global peatland C and N stocks.Peer reviewe

Seeding Science, Courting Conclusions: Reexamining the Intersection of Science, Corporate Cash, and the Law

Social scientists have expressed strong views on corporate influences over science, but most attention has been devoted to broad, Black/White arguments, rather than to actual mechanisms of influence. This paper summarizes an experience where involvement in a lawsuit led to the discovery of an unexpected mechanism: A large corporation facing a multibillion-dollar court judgment quietly provided generous funding to well-known scientists (including at least one Nobel prize winner) who would submit articles to "open," peer-reviewed journals, so that their "unbiased science" could be cited in an appeal to the Supreme Court. On balance, the corporation's most effective techniques of influence may have been provided not by overt pressure, but by encouraging scientists to continue thinking of themselves as independent and impartial

Towards a Smart and Socialised Augmented Reality

This paper introduces a nascent project aimed at exploring new avenues to support creativity, socialisation and community through smart interfaces for augment reality. Augmented reality has been so far largely conceptualised from a point of view of 'power users' seeking to support very specific applications, e.g. in training and simulation. With the availability of devices to mass market, new applications become possible, and new research problems open up. We offer a preliminary framework consisting of 2 orthogonal continua (virtual-real and human-thing) and 2 critical perspective (postphenomenology/posthumanism and cultural interface). With this poster we hope to stimulate valuable discussion and seek input from the CHI community about the challenges, opportunities, and theoretical perspectives underpinning a smart, socialised AR

The vanishing, or little erasures without significance?

The article discusses the importance of generative index in knowledge production and reproduction event in the performance studies in Great Britain. The author represents index as a means of inclusion and exclusion of knowledge and its intelligibility within the disciplinary framework of the performance. The discussion of vanished lexicon terms that the index identifies has wider implications for the authority of the index when used as a seemingly neutral organizational tool