166 research outputs found

    CCD Readout Electronics for the Subaru Prime Focus Spectrograph

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    We present details of the design for the CCD readout electronics for the Subaru Telescope Prime Focus Spectrograph (PFS). The spectrograph is comprised of four identical spectrograph modules, each collecting roughly 600 spectra. The spectrograph modules provide simultaneous wavelength coverage over the entire band from 380 nm to 1260 nm through the use of three separate optical channels: blue, red, and near infrared (NIR). A camera in each channel images the multi-object spectra onto a 4k x 4k, 15 um pixel, detector format. The two visible cameras use a pair of Hamamatsu 2k x 4k CCDs with readout provided by custom electronics, while the NIR camera uses a single Teledyne HgCdTe 4k x 4k detector and ASIC Sidecar to read the device. The CCD readout system is a custom design comprised of three electrical subsystems: the Back End Electronics (BEE), the Front End Electronics (FEE), and a Pre-amplifier. The BEE is an off-the-shelf PC104 computer, with an auxiliary Xilinx FPGA module. The computer serves as the main interface to the Subaru messaging hub and controls other peripheral devices associated with the camera, while the FPGA is used to generate the necessary clocks and transfer image data from the CCDs. The FEE board sets clock biases, substrate bias, and CDS offsets. It also monitors bias voltages, offset voltages, power rail voltage, substrate voltage and CCD temperature. The board translates LVDS clock signals to biased clocks and returns digitized analog data via LVDS. Monitoring and control messages are sent from the BEE to the FEE using a standard serial interface. The Pre-amplifier board resides behind the detectors and acts as an interface to the two Hamamatsu CCDs. The Pre-amplifier passes clocks and biases to the CCDs, and analog CCD data is buffered and amplified prior to being returned to the FEE.Comment: 14 pages, 15 figures, SPIE ATI 2014, Montrea

    Visible camera cryostat design and performance for the SuMIRe Prime Focus Spectrograph (PFS)

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    We describe the design and performance of the SuMIRe Prime Focus Spectrograph (PFS) visible camera cryostats. SuMIRe PFS is a massively multi-plexed ground-based spectrograph consisting of four identical spectrograph modules, each receiving roughly 600 fibers from a 2394 fiber robotic positioner at the prime focus. Each spectrograph module has three channels covering wavelength ranges 380~nm -- 640~nm, 640~nm -- 955~nm, and 955~nm -- 1.26~um, with the dispersed light being imaged in each channel by a f/1.07 vacuum Schmidt camera. The cameras are very large, having a clear aperture of 300~mm at the entrance window, and a mass of ∌\sim280~kg. In this paper we describe the design of the visible camera cryostats and discuss various aspects of cryostat performance

    Identification of Novel Candidate Risk Genes for Myelomeningocele Within the Glucose Homeostasis/Oxidative Stress and Folate/One-Carbon Metabolism Networks

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    BACKGROUND: Neural tube defects (NTDs) are the second most common complex birth defect, yet, our understanding of the genetic contribution to their development remains incomplete. Two environmental factors associated with NTDs are Folate and One Carbon Metabolism (FOCM) and Glucose Homeostasis and Oxidative Stress (GHOS). Utilizing next-generation sequencing of a large patient cohort, we identify novel candidate genes in these two networks to provide insights into NTD mechanisms. METHODS: Exome sequencing (ES) was performed in 511 patients, born with myelomeningocele, divided between European American and Mexican American ethnicities. Healthy control data from the Genome Aggregation database were ethnically matched and used as controls. Rare, high fidelity, nonsynonymous predicted damaging missense, nonsense, or canonical splice site variants in independently generated candidate gene lists for FOCM and GHOS were identified. We used a gene-based collapsing approach to quantify mutational burden in case and controls, with the control cohort estimated using cumulative allele frequencies assuming Hardy-Weinberg equilibrium. RESULTS: We identified 45 of 837 genes in the FOCM network and 22 of 568 genes in the GHOS network as possible NTD risk genes with p \u3c 0.05. No nominally significant risk genes were shared between ethnicities. Using a novel approach to mutational burden we identify 55 novel NTD risk associations. CONCLUSIONS: We provide a means of utilizing large publicly available sequencing datasets as controls for sequencing projects examining rare disease. This approach confirmed existing risk genes for myelomeningocele and identified possible novel risk genes. Lastly, it suggests possible distinct genetic etiologies for this malformation between different ethnicities

    Controlling magnetic order and quantum disorder in molecule-based magnets

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    We investigate the structural and magnetic properties of two molecule-based magnets synthesized from the same starting components. Their different structural motifs promote contrasting exchange pathways and consequently lead to markedly different magnetic ground states. Through examination of their structural and magnetic properties we show that [Cu(pyz)(H2O)(gly)2](ClO4)2 may be considered a quasi-one-dimensional quantum Heisenberg antiferromagnet whereas the related compound [Cu(pyz)(gly)](ClO4), which is formed from dimers of antiferromagnetically interacting Cu2+ spins, remains disordered down to at least 0.03 K in zero field but shows a field-temperature phase diagram reminiscent of that seen in materials showing a Bose-Einstein condensation of magnons

    “Because of mchango, I give my baby gripe water so he sleeps and stops crying”: Exclusive breastfeeding and parents’ concerns about colic-like symptoms in infants under 6 months in Lake Zone, Tanzania

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    Background Effective social and behavior change strategies for exclusive breastfeeding (EBF) rely on understanding how families interpret infant behavior and provide care. Little research thoroughly explores household use of non-prescribed medicine for infants under 6 months in rural Tanzania, which can interrupt EBF and may have other harmful unintended effects. Aim To explore parents’ use of non-prescribed medicine in response to infants’ colic-like symptoms during the EBF period. Methods We conducted thematic analysis of a series of qualitative, semi-structured interviews with 36 mothers and 30 fathers of infants 0-6 months in Lake Zone, Tanzania. Here, we focus on emergent themes related to concerns about colic-like symptoms and global implications for public health practitioners. Results Parents reported concerns about excessive crying and perceived infant abdominal pain, attributed to a potentially serious disease state locally known as mchango. Most parents gave non-prescribed medicines (e.g. gripe water, oral traditional medicine, and/or other commercial medicines) to treat or prevent mchango and associated symptoms, often including infant crying. After receiving supportive counselling on soothing techniques, most were willing to avoid giving non-prescribed medicines. Some reported continued challenges attributed to mchango symptoms, namely inconsolable crying. Conclusion While symptoms of mchango reported in this study overlapped with colic symptoms, literature in Tanzania suggests, in some cases, mchango is perceived to have spiritual origins and potentially be dangerous if left untreated. Empathetic counseling can offer parents knowledge and skills to manage colic-like symptoms without using non-prescribed medicines. Health workers need clear messages and training on risks of non-prescribed medicines and Tanzanian legislation banning its promotion and distribution

    Direct Economic Losses in the Northridge Earthquake: A Three-Year Post-Event Perspective

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    The Northridge earthquake will long be remembered for the unprecedented losses incurred as a result of a moderate-size event in a suburban area of Los Angeles. Current documented costs indicate that this event is the costliest disaster in U.S. history. Although it is difficult to estimate the full cost of this event, it is quite possible that total losses, excluding indirect effects, could reach as much as $40 billion. This would make the Northridge earthquake less severe than the Kobe event, which occurred exactly one year after the Northridge earthquake, but adds a bit of realism that a Kobe-type disaster is possible in the U.S. This paper attempts to put into perspective the direct capital losses associated with the Northridge earthquake. In doing so, we introduce the concept of hidden and/or undocumented costs that could double current estimates. In addition, we present the notion that a final estimate of loss may be impossible to achieve, although costs do begin to level off two years after the earthquake. Finally, we attempt to reconcile apparent differences between loss totals for two databases tracking similar information

    Prime Focus Spectrograph (PFS) for the Subaru Telescope: Overview, recent progress, and future perspectives

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    PFS (Prime Focus Spectrograph), a next generation facility instrument on the 8.2-meter Subaru Telescope, is a very wide-field, massively multiplexed, optical and near-infrared spectrograph. Exploiting the Subaru prime focus, 2394 reconfigurable fibers will be distributed over the 1.3 deg field of view. The spectrograph has been designed with 3 arms of blue, red, and near-infrared cameras to simultaneously observe spectra from 380nm to 1260nm in one exposure at a resolution of ~1.6-2.7A. An international collaboration is developing this instrument under the initiative of Kavli IPMU. The project is now going into the construction phase aiming at undertaking system integration in 2017-2018 and subsequently carrying out engineering operations in 2018-2019. This article gives an overview of the instrument, current project status and future paths forward.Comment: 17 pages, 10 figures. Proceeding of SPIE Astronomical Telescopes and Instrumentation 201

    Stem cell-derived porcine macrophages as a new platform for studying host-pathogen interactions

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    BACKGROUND: Infectious diseases of farmed and wild animals pose a recurrent threat to food security and human health. The macrophage, a key component of the innate immune system, is the first line of defence against many infectious agents and plays a major role in shaping the adaptive immune response. However, this phagocyte is a target and host for many pathogens. Understanding the molecular basis of interactions between macrophages and pathogens is therefore crucial for the development of effective strategies to combat important infectious diseases. RESULTS: We explored how porcine pluripotent stem cells (PSCs) can provide a limitless in vitro supply of genetically and experimentally tractable macrophages. Porcine PSC-derived macrophages (PSCdMs) exhibited molecular and functional characteristics of ex vivo primary macrophages and were productively infected by pig pathogens, including porcine reproductive and respiratory syndrome virus (PRRSV) and African swine fever virus (ASFV), two of the most economically important and devastating viruses in pig farming. Moreover, porcine PSCdMs were readily amenable to genetic modification by CRISPR/Cas9 gene editing applied either in parental stem cells or directly in the macrophages by lentiviral vector transduction. CONCLUSIONS: We show that porcine PSCdMs exhibit key macrophage characteristics, including infection by a range of commercially relevant pig pathogens. In addition, genetic engineering of PSCs and PSCdMs affords new opportunities for functional analysis of macrophage biology in an important livestock species. PSCs and differentiated derivatives should therefore represent a useful and ethical experimental platform to investigate the genetic and molecular basis of host-pathogen interactions in pigs, and also have wider applications in livestock. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12915-021-01217-8
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