Determination of overlap in lidar systems

The overlap profile, also known as crossover function or geometric form factor, is often a source of uncertainty for lidar measurements. This paper describes a method for measuring the overlap by presenting the lidar with a virtual cloud through the use of an imaging system. Results show good agreement with horizontal hard target lidar measurements and with geometric overlap calculated for the ideal aberration-free case

New laser technology to determine present weather parameters

Present weather sensors are becoming increasingly important as a means to augment networks of automated weather stations and extend the capability of manned observations. The classification of hydrometeors is one of the principal tasks that is addressed by present weather sensors. In this paper, we discuss a new laser-based technology for this purpose. The system improves upon current precipitation monitors by using a derivative of phase Doppler anemometry techniques to accurately determine particle speed and size. The instrument is also capable of distinguishing between liquid droplets and solid polycrystalline hydrometeors and can be used to estimate visibility. The incorporation of this technology into a meteorological station with other sensors, such as temperature and relative humidity probes, leads to the accurate classification of particle type. The example data shown are taken from tests in Leicestershire, England and Utah, USA and show the differences between solid and liquid precipitation events

COVID-19 and cognitive function: Evidence for increased processing speed variability in COVID-19 survivors and multifaceted impairment with long-COVID symptoms

Abstract Background There is increasing evidence for cognitive function to be negatively impacted by COVID-19. There is, however, limited research evaluating cognitive function pre- and post-COVID-19 using objective measures. Methods We examined processing speed, attention, working memory, executive function and memory in adults (≤69 years) with a history of COVID-19 (n = 129, none acutely unwell), compared to those with no known history of COVID-19 (n = 93). We also examined cognitive changes in a sub-group of COVID (n = 30) and non-COVID (n = 33) participants, compared to their pre-COVID-19 pandemic level. Results Cross-sectionally, the COVID group showed significantly larger intra-individual variability in processing speed, compared to the non-COVID group. The COVID sub-group also showed significantly larger intra-individual variability in processing speed, compared to their pre-COVID level; no significant change occurred in non-COVID participants over the same time scale. Other cognitive indices were not significantly impacted in the cross-sectional or within-subjects investigations, but participants (n = 20) who had needed hospitalisation due to COVID-19 showed poor attention and executive function relative to those who had not required hospitalisation (n = 109). Poor health and long-COVID symptoms correlated with poor cognitive function across domains in the COVID group. Conclusions The findings indicate a limited cognitive impact of COVID-19 with only intra-individual variability in processing speed being significantly impacted in an adult UK sample. However, those who required hospitalisation due to COVID-19 severity and/or experience long-COVID symptoms display multifaceted cognitive impairment and may benefit from repeated cognitive assessments and remediation efforts

Cognitive and Mental Health Trajectories of COVID-19: Role of Hospitalisation and Long-COVID Symptoms

Background: There is considerable evidence of cognitive impairment post COVID-19, especially in individuals with long-COVID symptoms, but limited research objectively evaluating whether such impairment attenuates or resolves over time, especially in young and middle-aged adults. Methods: Follow-up assessments (T2) of cognitive function (processing speed, attention, working memory, executive function, memory) and mental health were conducted in 138 adults (18-69 years) who had been assessed six months earlier (T1). Of these, 88 had a confirmed history of COVID-19 at T1 assessment (≥20 days post-diagnosis) and were also followed-up on COVID-19 related symptoms (acute and long-COVID); 50 adults had no known COVID-19 history at any point up to their T2 assessment. Results: From T1 to T2, a trend-level improvement occurred in intra-individual variability in processing speed in the COVID, relative to the non-COVID group. However, longer response/task completion times persisted in participants with COVID-19 related hospitalisation relative to those without COVID-19 related hospitalisation and non-COVID controls. There was a significant reduction in long-COVID symptom load, which correlated with improved executive function in non-hospitalised COVID-19 participants. The COVID group continued to self-report poorer mental health, irrespective of hospitalisation history, relative to non-COVID group. Conclusions: Although some cognitive improvement has occurred over a six-month period in young and middle-aged COVID-19 survivors, cognitive impairment persists in those with a history of COVID-19 related hospitalisation and/or long-COVID symptoms. Continuous follow-up assessments are required to determine whether cognitive function improves or possibly worsens, over time in hospitalised and long-COVID participants.British Academy (SRG21\211061)

Quality of Life and Social and Psychological Outcomes in Adulthood Following Allogeneic HSCT in Childhood for Inborn Errors of Immunity

BACKGROUND: Hematopoietic stem cell transplant (HSCT) is well established as a corrective treatment for many inborn errors of immunity (IEIs) presenting in childhood. Due to improved techniques, more transplants are undertaken and patients are living longer. However, long-term complications can significantly affect future health and quality of life. Previous research has focused on short-term medical outcomes and little is known about health or psychosocial outcomes in adulthood. OBJECTIVE: This project aimed to ascertain the long-term social and psychological outcomes for adults who underwent HSCT for IEI during childhood. METHODS: Adult patients, who had all undergone HSCT for IEI during childhood at two specialist immunology services at least 5 years previously, were invited to participate in the study. Questionnaires and practical tasks assessed their current functioning and circumstances. Information was also gathered from medical notes. Data was compared with population norms and a control group of participant-nominated siblings or friends. RESULTS: Eighty-three patients and 46 matched controls participated in the study. Patients reported significantly better physical health-related quality of life than the general population norm, but significantly worse than matched controls. Patient's self-reported physical health status and the perceived impact of their physical health on everyday life were worse than matched controls and patients reported higher levels of anxiety and lower mood than the general population. For those where their IEI diagnosis was not associated with a learning disability, cognitive function was generally within the normal range. CONCLUSIONS: Patients who have had a HSCT in childhood report mixed psychosocial outcomes in adulthood. More research is needed to establish screening protocols and targeted interventions to maximize holistic outcomes. CLINICAL IMPLICATIONS: Screening for holistic needs and common mental health difficulties should be part of routine follow-up. Information should be provided to patients and families in order to support decision-making regarding progression to transplant and the early identification of any difficulties

No Conclusive Evidence for Transits of Proxima b in MOST photometry

The analysis of Proxima Centauri's radial velocities recently led Anglada-Escud\'e et al. (2016) to claim the presence of a low mass planet orbiting the Sun's nearest star once every 11.2 days. Although the a-priori probability that Proxima b transits its parent star is just 1.5%, the potential impact of such a discovery would be considerable. Independent of recent radial velocity efforts, we observed Proxima Centauri for 12.5 days in 2014 and 31 days in 2015 with the MOST space telescope. We report here that we cannot make a compelling case that Proxima b transits in our precise photometric time series. Imposing an informative prior on the period and phase, we do detect a candidate signal with the expected depth. However, perturbing the phase prior across 100 evenly spaced intervals reveals one strong false-positive and one weaker instance. We estimate a false-positive rate of at least a few percent and a much higher false-negative rate of 20-40%, likely caused by the very high flare rate of Proxima Centauri. Comparing our candidate signal to HATSouth ground-based photometry reveals that the signal is somewhat, but not conclusively, disfavored (1-2 sigmas) leading us to argue that the signal is most likely spurious. We expect that infrared photometric follow-up could more conclusively test the existence of this candidate signal, owing to the suppression of flare activity and the impressive infrared brightness of the parent star.Comment: Accepted to ApJ. Posterior samples, MOST photometry and HATSouth photometry are all available at https://github.com/CoolWorlds/Proxim

Gr1int/high Cells Dominate the Early Phagocyte Response to Mycobacterial Lung Infection in Mice

Lung infection by Mycobacterium tuberculosis is characterized by chronic infection of lung-resident macrophages, long considered to be the primary hosts and determinants of the outcome of the early immune response. Although alveolar macrophages are well-known to host intracellular mycobacteria at later stages of disease, little is known about the earliest events of the innate immune response. The phagocytes that take up mycobacteria immediately following infection, and how the early lung phagocyte response is altered by vaccination with M. bovis bacille Calmette-Guérin (BCG) were unknown. Using BCG expressing the bright red fluorescent protein tdTomato and flow cytometry, we modeled early infection in C57BL/6 mice and tracked phagocyte population kinetics and uptake of mycobacteria, to better understand the involvement of specific phagocyte subsets. By 1 day post-infection, dose-dependent accumulation of neutrophils was observed and surprisingly, granulocytes comprised a greater proportion of infected phagocytes than alveolar macrophages. By 7 days post-infection alveolar macrophages had become the dominant BCG-associated phagocytes. Prior mucosal BCG exposure provided immunized mice with greater frequencies and numbers of lung macrophage subsets, and a significantly greater proportion of alveolar macrophages expressed CD11b prior to and following challenge infection. These data provide the first evidence of granulocytes as the dominant infected phagocyte subset early after mycobacterial infection, and highlight enhanced recruitment of lung macrophages as a factor associated with protection in BCG-immunized mice

The Multi-Object, Fiber-Fed Spectrographs for SDSS and the Baryon Oscillation Spectroscopic Survey

We present the design and performance of the multi-object fiber spectrographs for the Sloan Digital Sky Survey (SDSS) and their upgrade for the Baryon Oscillation Spectroscopic Survey (BOSS). Originally commissioned in Fall 1999 on the 2.5-m aperture Sloan Telescope at Apache Point Observatory, the spectrographs produced more than 1.5 million spectra for the SDSS and SDSS-II surveys, enabling a wide variety of Galactic and extra-galactic science including the first observation of baryon acoustic oscillations in 2005. The spectrographs were upgraded in 2009 and are currently in use for BOSS, the flagship survey of the third-generation SDSS-III project. BOSS will measure redshifts of 1.35 million massive galaxies to redshift 0.7 and Lyman-alpha absorption of 160,000 high redshift quasars over 10,000 square degrees of sky, making percent level measurements of the absolute cosmic distance scale of the Universe and placing tight constraints on the equation of state of dark energy. The twin multi-object fiber spectrographs utilize a simple optical layout with reflective collimators, gratings, all-refractive cameras, and state-of-the-art CCD detectors to produce hundreds of spectra simultaneously in two channels over a bandpass covering the near ultraviolet to the near infrared, with a resolving power R = \lambda/FWHM ~ 2000. Building on proven heritage, the spectrographs were upgraded for BOSS with volume-phase holographic gratings and modern CCD detectors, improving the peak throughput by nearly a factor of two, extending the bandpass to cover 360 < \lambda < 1000 nm, and increasing the number of fibers from 640 to 1000 per exposure. In this paper we describe the original SDSS spectrograph design and the upgrades implemented for BOSS, and document the predicted and measured performances.Comment: 43 pages, 42 figures, revised according to referee report and accepted by AJ. Provides background for the instrument responsible for SDSS and BOSS spectra. 4th in a series of survey technical papers released in Summer 2012, including arXiv:1207.7137 (DR9), arXiv:1207.7326 (Spectral Classification), and arXiv:1208.0022 (BOSS Overview

VUV spectroscopy of an electron irradiated benzene : carbon dioxide interstellar ice analogue

We present the first vacuum ultraviolet spectroscopic study of an interstellar ice analogue of a 1 : 100 benzene (C6H6) : carbon dioxide (CO2) mixture which has been energetically processed with 1 keV electrons. We have exploited the fact that benzene has a relatively high photoabsorption cross section in the vacuum ultraviolet region to study this dilute mixture of benzene. Before irradiation with 1 keV electrons, we observed that the benzene electronic transition bands in the C6H6 : CO2 mixture exhibits a blueshift in band position towards energies observed in the gas-phase compared with that of pure, amorphous benzene and we have attributed this to a matrix isolation effect. After irradiation, a lowering in intensity of both the carbon dioxide and benzene electronic transition bands was observed, as well as the formation of the small irradiation product, carbon monoxide. A residue was obtained at 200 K which showed characteristic features of the benzene electronic transition of 1E1u ← 1A1g, but with additional structure suggesting the formation of a benzene derivative