1,702 research outputs found

    Identification of a gene encoding GMP synthetase from a Neurospora crassa cDNA library by bacterial complementation

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    We report the isolation and identification of a gene encoding GMP synthetase from a Neurospora crassa cDNA library. Phage infection of the purine-requiring Escherichia coli strain SØ3834 using the NO3- induced cDNA phage library from the Fungal Genetics Stock Center resulted in colonies able to grow on minimal media with no added purine source. A plasmid, termed pGMPS1, was isolated from one of these colonies and shown to reproducibly support growth of strain SØ3834 in the absence of purines in the media. Identification of this gene as one encoding GMP synthetase is confirmed by DNA sequencing and comparison to the known guaA gene from yeast

    A Large-Diameter Hollow-Shaft Cryogenic Motor Based on a Superconducting Magnetic Bearing for Millimeter-Wave Polarimetry

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    In this paper we present the design and measured performance of a novel cryogenic motor based on a superconducting magnetic bearing (SMB). The motor is tailored for use in millimeter-wave half-wave plate (HWP) polarimeters, where a HWP is rapidly rotated in front of a polarization analyzer or polarization-sensitive detector. This polarimetry technique is commonly used in cosmic microwave background (CMB) polarization studies. The SMB we use is composed of fourteen yttrium barium copper oxide (YBCO) disks and a contiguous neodymium iron boron (NdFeB) ring magnet. The motor is a hollow-shaft motor because the HWP is ultimately installed in the rotor. The motor presented here has a 100 mm diameter rotor aperture. However, the design can be scaled up to rotor aperture diameters of approximately 500 mm. Our motor system is composed of four primary subsystems: (i) the rotor assembly, which includes the NdFeB ring magnet, (ii) the stator assembly, which includes the YBCO disks, (iii) an incremental encoder, and (iv) the drive electronics. While the YBCO is cooling through its superconducting transition, the rotor is held above the stator by a novel hold and release mechanism (HRM). The encoder subsystem consists of a custom-built encoder disk read out by two fiber optic readout sensors. For the demonstration described in this paper, we ran the motor at 50 K and tested rotation frequencies up to approximately 10 Hz. The feedback system was able to stabilize the the rotation speed to approximately 0.4%, and the measured rotor orientation angle uncertainty is less than 0.15 deg. Lower temperature operation will require additional development activities, which we will discuss

    Toolbox for analyzing finite two-state trajectories

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    In many experiments, the aim is to deduce an underlying multi-substate on-off kinetic scheme (KS) from the statistical properties of a two-state trajectory. However, the mapping of a KS into a two-state trajectory leads to the loss of information about the KS, and so, in many cases, more than one KS can be associated with the data. We recently showed that the optimal way to solve this problem is to use canonical forms of reduced dimensions (RD). RD forms are on-off networks with connections only between substates of different states, where the connections can have non-exponential waiting time probability density functions (WT-PDFs). In theory, only a single RD form can be associated with the data. To utilize RD forms in the analysis of the data, a RD form should be associated with the data. Here, we give a toolbox for building a RD form from a finite two-state trajectory. The methods in the toolbox are based on known statistical methods in data analysis, combined with statistical methods and numerical algorithms designed specifically for the current problem. Our toolbox is self-contained - it builds a mechanism based only on the information it extracts from the data, and its implementation on the data is fast (analyzing a 10^6 cycle trajectory from a thirty-parameter mechanism takes a couple of hours on a PC with a 2.66 GHz processor). The toolbox is automated and is freely available for academic research upon electronic request

    Aphids

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    Methods for Detecting and Quantifying Viable Bacterial Endo-Spores

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    Methods and systems for detecting viable bacterial endospores in a sample and related methods to quantify viable bacterial endospores in a sample

    The relationship between physical ill-health and mental ill-health in adults with intellectual disabilities

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    Background: People with intellectual disabilities face a much greater burden and earlier onset of physical and mental ill‐health than the general adult population. Physical–mental comorbidity has been shown to result in poorer outcomes in the general population, but little is known about this relationship in adults with intellectual disabilities. Aims: To identify whether physical ill‐health is associated with mental ill‐health in adults with intellectual disabilities and whether the extent of physical multi‐morbidity can predict the likelihood of mental ill‐health. To identify any associations between types of physical ill‐health and mental ill‐health. Method: A total of 1023 adults with intellectual disabilities underwent comprehensive health assessments. Binary logistic regressions were undertaken to establish any association between the independent variables: total number of physical health conditions, physical conditions by International Classification of Disease‐10 chapter and specific physical health conditions; and the dependent variables: problem behaviours, mental disorders of any type. All regressions were adjusted for age, gender, level of intellectual disabilities, living arrangements, neighbourhood deprivation and Down syndrome. Results: The extent of physical multi‐morbidity was not associated with mental ill‐health in adults with intellectual disabilities as only 0.8% of the sample had no physical conditions. Endocrine disease increased the risk of problem behaviours [odds ratio (OR): 1.22, 95% confidence interval (CI): 1.02–1.47], respiratory disease reduced the risk of problem behaviours (OR: 0.73, 95% CI: 0.54–0.99) and mental ill‐health of any type (OR: 0.73, 95% CI: 0.58–0.92), and musculoskeletal disease reduced the risk of mental ill‐health of any type (OR: 0.84, 95% CI: 0.73–0.98). Ischaemic heart disease increased the risk of problem behaviours approximately threefold (OR: 3.29, 95% CI: 1.02–10.60). Conclusions: The extent of physical multi‐morbidity in the population with intellectual disabilities is overwhelming, such that associations are not found with mental ill‐health. Mental health interventions and preventative measures are essential for the entire population with intellectual disabilities and should not be focussed on subgroups based on overall health burden

    A LEKID-based CMB instrument design for large-scale observations in Greenland

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    We present the results of a feasibility study, which examined deployment of a ground-based millimeter-wave polarimeter, tailored for observing the cosmic microwave background (CMB), to Isi Station in Greenland. The instrument for this study is based on lumped-element kinetic inductance detectors (LEKIDs) and an F/2.4 catoptric, crossed-Dragone telescope with a 500 mm aperture. The telescope is mounted inside the receiver and cooled to <4<\,4 K by a closed-cycle 4^4He refrigerator to reduce background loading on the detectors. Linearly polarized signals from the sky are modulated with a metal-mesh half-wave plate that is rotated at the aperture stop of the telescope with a hollow-shaft motor based on a superconducting magnetic bearing. The modular detector array design includes at least 2300 LEKIDs, and it can be configured for spectral bands centered on 150~GHz or greater. Our study considered configurations for observing in spectral bands centered on 150, 210 and 267~GHz. The entire polarimeter is mounted on a commercial precision rotary air bearing, which allows fast azimuth scan speeds with negligible vibration and mechanical wear over time. A slip ring provides power to the instrument, enabling circular scans (360 degrees of continuous rotation). This mount, when combined with sky rotation and the latitude of the observation site, produces a hypotrochoid scan pattern, which yields excellent cross-linking and enables 34\% of the sky to be observed using a range of constant elevation scans. This scan pattern and sky coverage combined with the beam size (15~arcmin at 150~GHz) makes the instrument sensitive to 5<<10005 < \ell < 1000 in the angular power spectra
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