218 research outputs found

    Measuring the Edwards-Anderson order parameter of the Bose glass : a quantum gas microscope approach

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    We thank D Cassettari, A Daley, S Denny, J Keeling, P Kirton and A Trombettoni for insightful discussions and assistance. Computations were performed on the EPSRC CDT Computer Cluster and the University of St Andrews School of Physics & Astronomy computer cluster. SJT acknowledges studentship funding from EPSRC under grant no. EP/G03673X/1. GDB acknowledges support from the Leverhulme Trust RPG-2013-074.With the advent of spatially resolved fluorescence imaging in quantum gas microscopes, it is now possible to directly image glassy phases and probe the local effects of disorder in a highly controllable setup. Here we present numerical calculations using a spatially resolved local mean-field theory, show that it captures the essential physics of the disordered system and use it to simulate the density distributions seen in single-shot fluorescence microscopy. From these simulated images we extract local properties of the phases which are measurable by a quantum gas microscope and show that unambiguous detection of the Bose glass is possible. In particular, we show that experimental determination of the Edwards-Anderson order parameter is possible in a strongly correlated quantum system using existing experiments. We also suggest modifications to the experiments which will allow further properties of the Bose glass to be measured.PostprintPeer reviewe

    Can quantum gas microscopes directly image exotic glassy phases?

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    With the advent of spatially resolved fluorescence imaging in quantum gas microscopes (see e.g. [1]), it is now possible to directly image glassy phases and probe the local effects of disorder in a highly controllable setup. Here we present numerical calculations using a spatially resolved local mean-field theory, show that it captures the essential physics of the disordered system, and use it to simulate the density distributions seen in single-shot fluorescence microscopy [2]. From these simulated images we extract local properties of the phases which are measurable by a quantum gas microscope and show that unambiguous detection of the Bose glass is possible. In particular, we show that experimental determination of the Edwards-Anderson order parameter is possible in a strongly correlated quantum system using existing experiments. We also suggest modifications to the experiments by using spatial light modulators (see [3] and references therein) to tailor the lattice, which will allow further properties of the Bose glass to be measured. References: [1] E Haller, et al., "Single-atom imaging of fermions in a quantum-gas microscope" Nature Physics 11, 738 (2015) [2] S J Thomson, et al., "Measuring the Edwards-Anderson order parameter of the Bose glass: A quantum gas microscope approach" Phys. Rev. A 94, 051601(R) (2016) [3] F Buccheri, et al., "Holographic optical traps for atom-based topological Kondo devices" New J. Phys. 18, 075012 (2016)PostprintNon peer reviewe

    Long-distance Movement over a Period of Days by a Female Myotis lucifugus in Newfoundland, Canada

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    Myotis lucifugus (Little Brown Myotis) is a regionally migrating bat, widely distributed throughout North America. Through long-term monitoring systems deployed in 2 locations in Newfoundland, Canada, we recorded the movement of an adult female of at least 375 km over a period of 4 nights. Although not the longest travel distance recorded for this species, this observation emphasizes the capabilities of Little Brown Myotis for long-distance flights, the potential connectivity among distant maternity groups, and the value of long-term monitoring programs. To fully understand the movement patterns of Little Brown Myotis, advancements in technology and greater research effort are needed.Natural Sciences and Engineering Research Council of Canada || Newfoundland and Labrador Wildlife Division || Saint Mary’s University || University of Waterlo

    Design of an Imaging Payload for Earth Observation from a Nanosatellite

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    A compact imaging payload consisting of visible-near infrared and short-wave infrared capability is being developed to demonstrate low-cost wildfire monitoring among other Earth observations. Iris is a 1U multispectral push-broom imager that is capable of generating spectral data pertinent for wildfire science and wildfire risk analysis from a CubeSat platform. This payload is slated to fly on-board Ex-Alta 2, the University of Alberta’s second CubeSat and Alberta’s contribution to the Canadian CubeSat Project, to be deployed from the International Space Station in 2022. Iris features four closely integrated designs: optical, structural, electronics, and firmware. The mechanical and electronic interfaces of Iris are suited for modular integration into 1U of other generic CubeSat structures. The design has significant constraints on mass, size, performance, and cost. The current optical design features two compact lightpaths within the housing for imaging in short-wave infrared, near-infrared, blue, and red bands (center wavelengths at 2100, 865, 490, and 665 nm, respectively). Design simulations suggest achievement of a signal-to-noise ratio greater than 20 dB across all bands and a spatial resolution of 360 mor better averaged across the field-of-view. Taken together, this demonstrates significant scientific value for minimized cost and instrument volume. This design uses exclusively commercially available lenses, providing significant overall cost savings. The structural housing of Iris consists of 6061 T6 Aluminum, which provides a light-tight optical path for the visible to near-infrared and short-wave infrared light paths, as well as mounting for the optics and printed circuit board to the CubeSat structure within the required tolerances. A 45-degree folding mirror is employed to provide an extended optical lightpath within 1U with no deployable optics. The lens and mirror mounts are fitted with manual adjustment mechanisms for post-assembly alignment of the optical elements. This feature allows the team to perform small modifications to the axial position of the lenses as well as the folding mirror plane without having to re-manufacture the structure, saving time and cost. Within Iris, a subsystem named Electra features a custom filtered CMV4000 CMOS detector from ams AG integrated alongside a custom filtered G11478-512WB InGaAs linear array from Hamamatsu. Electra is a custom printed circuit board which houses an Intel Cyclone V system-on-chip field-programmable gate array, 512 MB of DDR3 synchronous dynamic random-access memory, and other supporting infrastructure for controlling Iris imaging operations and handling spectral data. An in-house software and VHDL suite is implemented within Electra for sensor control, memory management, and all off-board communications. Software functionality includes data compression and a cloud detection algorithm, wherein images are ranked based on heuristic value of relative cloud content, together increasing scientific value per spacecraft link time. A full proto-flight model of Iris is scheduled for manufacturing and testing in Q4 2021. Following manufacturing, comprehensive validation analysis and characterization will be performed, confirming ability to meet mission requirements

    Mosquito community and West Nile virus risk on a National Guard training base in Oklahoma

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    Military bases are important areas for mosquito surveillance to maintain active duty combat readiness and protect training exercises. The aim of this study was to assist Camp Gruber National Guard training facility personnel to assess their mosquito community and West Nile virus (WNV) risk using biweekly sampling of 50 sites. Between May and October 2018, 10,259 adult female mosquitoes consisting of 6 genera and 26 species were collected over 662 trap-nights using 2 trap types. The most commonly collected genus was Culex (72.2% of total), followed by Psorophora (13.3%) and Aedes (10.2%). Of note, most of the medically important species were collected in the area containing troop living quarters, including 1 WNV-positive pool of Culex tarsalis. Two specimens of Aedes aegypti were collected around a vehicle storage area. While smaller in land mass size than many other active military bases in Oklahoma, the diversity of species at Camp Gruber was comparable to collections from 4 larger bases in Oklahoma. These data demonstrate the need for regular season-long mosquito monitoring of training bases to protect the health of active duty and reserve military personnel.Peer reviewedEntomology and Plant Patholog

    The IUPHAR/BPS Guide to PHARMACOLOGY in 2018: updates and expansion to encompass the new guide to IMMUNOPHARMACOLOGY.

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    The IUPHAR/BPS Guide to PHARMACOLOGY (GtoPdb, www.guidetopharmacology.org) and its precursor IUPHAR-DB, have captured expert-curated interactions between targets and ligands from selected papers in pharmacology and drug discovery since 2003. This resource continues to be developed in conjunction with the International Union of Basic and Clinical Pharmacology (IUPHAR) and the British Pharmacological Society (BPS). As previously described, our unique model of content selection and quality control is based on 96 target-class subcommittees comprising 512 scientists collaborating with in-house curators. This update describes content expansion, new features and interoperability improvements introduced in the 10 releases since August 2015. Our relationship matrix now describes ∼9000 ligands, ∼15 000 binding constants, ∼6000 papers and ∼1700 human proteins. As an important addition, we also introduce our newly funded project for the Guide to IMMUNOPHARMACOLOGY (GtoImmuPdb, www.guidetoimmunopharmacology.org). This has been 'forked' from the well-established GtoPdb data model and expanded into new types of data related to the immune system and inflammatory processes. This includes new ligands, targets, pathways, cell types and diseases for which we are recruiting new IUPHAR expert committees. Designed as an immunopharmacological gateway, it also has an emphasis on potential therapeutic interventions

    Gold(III), Mercury(II), and Palladium(II) Complexes of a Series of Isomeric Bis(mono- and dialkoxyphenyl)pyridines : Introduction of Gold through Transmetalation and Catalysis

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    A series of isomeric bis-2,6-(monoalkoxyphenyl)pyridine and bis-2,6-(dialkoxyphenyl)pyridine ligands were synthesized and characterized. In order to prepare their chlorogold(III) complexes, intermediate chloromercury(II) complexes were first prepared, but unlike observations from previous studies where they were obtained impure and at best in moderate yield, here pure complexes were synthesized, many in rather high yields. Depending on the substitution pattern of the alkoxy chains on the ligands, mono- and/or dimercurated complexes were obtained, characterized by 1H, 13C{1H}, and 199Hg NMR spectroscopy as well as, in several cases, by X-ray crystallography. Factors that may explain this unusual reactivity are discussed. In most cases, transmetalation to the related chlorogold(III) complex proceeded smoothly, although lower yields were obtained when starting from doubly mercurated precursors. Prompted by the propensity of these ligands to mercurate, attempts were made to effect direct auration, but none was successful. However, dimeric, orthometalated complexes of palladium(II) could be prepared and were also amenable to transmetalation to the chlorogold(III) complex, providing for a mercury-free synthesis

    Prevalence of symptoms, comorbidities, fibrin amyloid microclots and platelet pathology in individuals with Long COVID/Post-Acute Sequelae of COVID-19 (PASC)

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    BackgroundFibrin(ogen) amyloid microclots and platelet hyperactivation previously reported as a novel finding in South African patients with the coronavirus 2019 disease (COVID-19) and Long COVID/Post-Acute Sequelae of COVID-19 (PASC), might form a suitable set of foci for the clinical treatment of the symptoms of Long COVID/PASC. A Long COVID/PASC Registry was subsequently established as an online platform where patients can report Long COVID/PASC symptoms and previous comorbidities.MethodsIn this study, we report on the comorbidities and persistent symptoms, using data obtained from 845 South African Long COVID/PASC patients. By using a previously published scoring system for fibrin amyloid microclots and platelet pathology, we also analysed blood samples from 80 patients, and report the presence of significant fibrin amyloid microclots and platelet pathology in all cases.ResultsHypertension, high cholesterol levels (dyslipidaemia), cardiovascular disease and type 2 diabetes mellitus (T2DM) were found to be the most important comorbidities. The gender balance (70% female) and the most commonly reported Long COVID/PASC symptoms (fatigue, brain fog, loss of concentration and forgetfulness, shortness of breath, as well as joint and muscle pains) were comparable to those reported elsewhere. These findings confirmed that our sample was not atypical. Microclot and platelet pathologies were associated with Long COVID/PASC symptoms that persisted after the recovery from acute COVID-19.ConclusionsFibrin amyloid microclots that block capillaries and inhibit the transport of O2 to tissues, accompanied by platelet hyperactivation, provide a ready explanation for the symptoms of Long COVID/PASC. Removal and reversal of these underlying endotheliopathies provide an important treatment option that urgently warrants controlled clinical studies to determine efficacy in patients with a diversity of comorbidities impacting on SARS-CoV-2 infection and COVID-19 severity. We suggest that our platelet and clotting grading system provides a simple and cost-effective diagnostic method for early detection of Long COVID/PASC as a major determinant of effective treatment, including those focusing on reducing clot burden and platelet hyperactivation
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