41 research outputs found

    RFI Mitigation and Testing Employed at GGAO for NASA's Space Geodesy Project (SGP)

    Get PDF
    Radio Frequency Interference (RFI) Mitigation at Goddard Geophysical and Astronomical Observatory (GGAO) has been addressed in three different ways by NASA's Space Geodesy Project (SGP); masks, blockers, and filters. All of these techniques will be employed at the GGAO, to mitigate the RFI consequences to the Very Long Baseline Interferometer

    A Persistence Detector for Metabolic Network Rewiring in an Animal

    Get PDF
    Biological systems must possess mechanisms that prevent inappropriate responses to spurious environmental inputs. Caenorhabditis elegans has two breakdown pathways for the short-chain fatty acid propionate: a canonical, vitamin B12-dependent pathway and a propionate shunt that is used when vitamin B12 levels are low. The shunt pathway is kept off when there is sufficient flux through the canonical pathway, likely to avoid generating shunt-specific toxic intermediates. Here, we discovered a transcriptional regulatory circuit that activates shunt gene expression upon propionate buildup. Nuclear hormone receptor 10 (NHR-10) and NHR-68 function together as a persistence detector in a type 1, coherent feed-forward loop with an AND-logic gate to delay shunt activation upon propionate accumulation and to avoid spurious shunt activation in response to a non-sustained pulse of propionate. Together, our findings identify a persistence detector in an animal, which transcriptionally rewires propionate metabolism to maintain homeostasis

    Developing a New Generation of Integrated Micro-Spec Far Infrared Spectrometers for the EXperiment for Cryogenic Large-Aperture Intensity Mapping (EXCLAIM)

    Full text link
    The current state of far-infrared astronomy drives the need to develop compact, sensitive spectrometers for future space and ground-based instruments. Here we present details of the μ\rm \mu-Spec spectrometers currently in development for the far-infrared balloon mission EXCLAIM. The spectrometers are designed to cover the 555714 μ\rm 555 - 714\ \mum range with a resolution of $\rm R\ =\ \lambda / \Delta\lambda\ =\ 512atthe at the \rm 638\ \mumbandcenter.ThespectrometerdesignincorporatesaRowlandgratingspectrometerimplementedinaparallelplatewaveguideonalowlosssinglecrystalSichip,employingNbmicrostripplanartransmissionlinesandthinfilmAlkineticinductancedetectors(KIDs).TheEXCLAIMm band center. The spectrometer design incorporates a Rowland grating spectrometer implemented in a parallel plate waveguide on a low-loss single-crystal Si chip, employing Nb microstrip planar transmission lines and thin-film Al kinetic inductance detectors (KIDs). The EXCLAIM \rm \muSpecdesignisanadvancementuponasuccessful-Spec design is an advancement upon a successful \rm R = 64\ \muSpecprototype,andcanbeconsideredasubmmsuperconductingphotonicintegratedcircuit(PIC)thatcombinesspectraldispersionanddetection.Thedesignoperatesinasingle-Spec prototype, and can be considered a sub-mm superconducting photonic integrated circuit (PIC) that combines spectral dispersion and detection. The design operates in a single M{=}2gratingorder,allowingonespectrometertocoverthefullEXCLAIMbandwithoutrequiringamultiorderfocalplane.TheEXCLAIMinstrumentwillflysixspectrometers,whicharefabricatedonasingle150mmdiameterSiwafer.FabricationinvolvesaflipwaferbondingprocesswithpatterningofthesuperconductinglayersonbothsidesoftheSidielectric.Thespectrometersaredesignedtooperateat100mK,andwillinclude355AlKIDdetectorstargetingagoalofNEP grating order, allowing one spectrometer to cover the full EXCLAIM band without requiring a multi-order focal plane. The EXCLAIM instrument will fly six spectrometers, which are fabricated on a single 150 mm diameter Si wafer. Fabrication involves a flip-wafer-bonding process with patterning of the superconducting layers on both sides of the Si dielectric. The spectrometers are designed to operate at 100 mK, and will include 355 Al KID detectors targeting a goal of NEP {\sim}8\times10^{-19} \rm W/\sqrt{Hz}.Wesummarizethedesign,fabrication,andongoingdevelopmentofthese. We summarize the design, fabrication, and ongoing development of these \rm \mu$-Spec spectrometers for EXCLAIM.Comment: 9 pages, 5 figures, to appear in the Proceedings of the SPIE Astronomical Telescopes + Instrumentation (2022

    High seroprevalence of anti-SARS-CoV-2 antibodies among Ethiopian healthcare workers

    Get PDF
    BACKGROUND: COVID-19 pandemic has a devastating impact on the economies and health care system of sub-Saharan Africa. Healthcare workers (HWs), the main actors of the health system, are at higher risk because of their occupation. Serology-based estimates of SARS-CoV-2 infection among HWs represent a measure of HWs' exposure to the virus and could be used as a guide to the prevalence of SARS-CoV-2 in the community and valuable in combating COVID-19. This information is currently lacking in Ethiopia and other African countries. This study aimed to develop an in-house antibody testing assay, assess the prevalence of SARS-CoV-2 antibodies among Ethiopian high-risk frontline HWs. METHODS: We developed and validated an in-house Enzyme-Linked Immunosorbent Assay (ELISA) for specific detection of anti-SARS-CoV-2 receptor binding domain immunoglobin G (IgG) antibodies. We then used this assay to assess the seroprevalence among HWs in five public hospitals located in different geographic regions of Ethiopia. From consenting HWs, blood samples were collected between December 2020 and February 2021, the period between the two peaks of COVID-19 in Ethiopia. Socio-demographic and clinical data were collected using questionnaire-based interviews. Descriptive statistics and bivariate and multivariate logistic regression were used to determine the overall and post-stratified seroprevalence and the association between seropositivity and potential risk factors. RESULTS: Our successfully developed in-house assay sensitivity was 100% in serum samples collected 2- weeks after the first onset of symptoms whereas its specificity in pre-COVID-19 pandemic sera was 97.7%. Using this assay, we analyzed a total of 1997 sera collected from HWs. Of 1997 HWs who provided a blood sample, and demographic and clinical data, 51.7% were females, 74.0% had no symptoms compatible with COVID-19, and 29.0% had a history of contact with suspected or confirmed patients with SARS-CoV-2 infection. The overall seroprevalence was 39.6%. The lowest (24.5%) and the highest (48.0%) seroprevalence rates were found in Hiwot Fana Specialized Hospital in Harar and ALERT Hospital in Addis Ababa, respectively. Of the 821 seropositive HWs, 224(27.3%) of them had a history of symptoms consistent with COVID-19 while 436 (> 53%) of them had no contact with COVID-19 cases as well as no history of COVID-19 like symptoms. A history of close contact with suspected/confirmed COVID-19 cases is associated with seropositivity (Adjusted Odds Ratio (AOR) = 1.4, 95% CI 1.1-1.8; p = 0.015). CONCLUSION: High SARS-CoV-2 seroprevalence levels were observed in the five Ethiopian hospitals. These findings highlight the significant burden of asymptomatic infection in Ethiopia and may reflect the scale of transmission in the general population

    Quality assessment of health management information system (HMIS) data for maternal and child health in Jimma zone, Ethiopia

    Get PDF
    Health management information system (HMIS) data underpin attainment of health targets in low- and middle-income countries. However, the quality of HMIS data is often poor. The study appraised the completeness, timeliness, and internal consistency of eight key maternal and child health (MCH) indicators collected for all the primary health care units (PHCUs) located within three districts of Jimma Zone, Ethiopia. Results show that the HMIS may over-report the coverage of key MCH services, namely, antenatal care, skilled birth attendance and postnatal care. The quality of data at the zonal level could be improved to inform MCH research and programmatic efforts.Global Affairs Canada (GAC)Canadian institutes of Health Research (CIHR

    Experiment for cryogenic large-aperture intensity mapping: instrument design

    Get PDF
    The experiment for cryogenic large-aperture intensity mapping (EXCLAIM) is a balloon-borne telescope designed to survey star formation in windows from the present to z  =  3.5. During this time, the rate of star formation dropped dramatically, while dark matter continued to cluster. EXCLAIM maps the redshifted emission of singly ionized carbon lines and carbon monoxide using intensity mapping, which permits a blind and complete survey of emitting gas through statistics of cumulative brightness fluctuations. EXCLAIM achieves high sensitivity using a cryogenic telescope coupled to six integrated spectrometers employing kinetic inductance detectors covering 420 to 540 GHz with spectral resolving power R  =  512 and angular resolution ≈4  arc min. The spectral resolving power and cryogenic telescope allow the survey to access dark windows in the spectrum of emission from the upper atmosphere. EXCLAIM will survey 305  deg2 in the Sloan Digital Sky Survey Stripe 82 field from a conventional balloon flight in 2023. EXCLAIM will also map several galactic fields to study carbon monoxide and neutral carbon emission as tracers of molecular gas. We summarize the design phase of the mission
    corecore