2,151 research outputs found

    Electrical cross talk of a frequency division multiplexing readout for a transition edge sensor bolometer array

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    We have characterized and mapped the electrical cross talk (ECT) of a frequency division multiplexing (FDM) system with a transition edge sensor (TES) bolometer array, which is intended for space applications. By adding a small modulation at 120 Hz to the AC bias voltage of one bolometer and measuring the cross talk response in the current noise spectra of the others simultaneously, we have for the first time mapped the ECT level of 61 pixels with a nominal frequency spacing of 32 kHz in a 61 × 61 matrix and a carrier frequency ranging from 1 MHz to 4 MHz. We find that about 94% of the pixels show an ECT level of less than 0.4%. Only the adjacent pixels reach this level, and the ECT for the rest of the pixels is less than 0.1%. We also observe higher ECT levels, up to 10%, between some of the pixels, which have bundled long, parallel coplanar wires connecting TES bolometers to inductor-capacitor filters. In this case, the high mutual inductances dominate. To mitigate this source of ECT, the coplanar wires should be replaced by microstrip wires in the array. Our study suggests that an FDM system can have a relatively low ECT level, e.g., around 0.4% if the frequency spacing is 30 kHz. Our results successfully demonstrate a low electrical cross talk for a space FDM technology

    The effect of RaceRunning on cardiometabolic disease risk factors and functional mobility in young people with moderate-to-severe cerebral palsy: protocol for a feasibility study

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    Copyright © Author(s) (or their employer(s)) 2020. Introduction: There is consistent evidence that people with cerebral (CP) do not engage in the recommended physical activity guidelines for the general population from a young age. Participation in moderate-to-vigorous physical activity is particularly reduced in people with CP who have moderate-to-severe disability. RaceRunning is a growing disability sport that provides an opportunity for people with moderate-to-severe disability to participate in physical activity in the community. It allows those who are unable to walk independently, to propel themselves using a RaceRunning bike, which has a breastplate for support but no pedals. The aim of this study is to examine the feasibility and acceptability of RaceRunning for young people with moderate-to-severe CP and the feasibility of conducting a definitive study of the effect of RaceRunning on cardiometabolic disease risk factors and functional mobility. Methods and analysis: Twenty-five young people (age 5-21 yr) with CP or acquired brain injury affecting co-ordination will be included in this single arm intervention study. Participants will take part in one RaceRunning session each week for 24 weeks. Outcomes assessed at baseline, 12 and 24 weeks include body mass index, waist circumference, blood pressure, muscle strength, cardiorespiratory fitness, physical activity and sedentary behaviour, functional mobility, activity competence and psychosocial impact. Adverse events will be systematically recorded throughout the 24 weeks. Focus groups will be conducted with participants and/or parents to explore their views and experiences of taking part in RaceRunning. Ethics and dissemination: Approval has been granted by Queen Margaret University Research Ethics Committee (REC) and the South East of Scotland REC. Results will be disseminated through peer-reviewed journals and distributed to people with CP and their families through RaceRunning and Athletic Clubs, NHS trusts, and organisations for people with disabilities. Trial registration number: ClinicalTrials.gov Identifier: NCT04034342. Protocol version 1.0; pre-results.Action Medical Research and Chartered Society of Physiotherapy Charitable Trust.Joint award from Action Medical Research and Chartered Society of Physiotherapy Charitable Trust

    A Herschel/PACS Far Infrared Line Emission Survey of Local Luminous Infrared Galaxies

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    We present an analysis of [OI]63, [OIII]88, [NII]122 and [CII]158 far-infrared (FIR) fine-structure line observations obtained with Herschel/PACS, for ~240 local luminous infrared galaxies (LIRGs) in the Great Observatories All-sky LIRG Survey (GOALS). We find pronounced declines -deficits- of line-to-FIR-continuum emission for [NII]122, [OI]63 and [CII]158 as a function of FIR color and infrared luminosity surface density, ΣIR\Sigma_{\rm IR}. The median electron density of the ionized gas in LIRGs, based on the [NII]122/[NII]205 ratio, is nen_{\rm e} = 41 cm3^{-3}. We find that the dispersion in the [CII]158 deficit of LIRGs is attributed to a varying fractional contribution of photo-dissociation-regions (PDRs) to the observed [CII]158 emission, f([CII]PDR) = [CII]PDR/[CII], which increases from ~60% to ~95% in the warmest LIRGs. The [OI]63/[CII]158PDR ratio is tightly correlated with the PDR gas kinetic temperature in sources where [OI]63 is not optically-thick or self-absorbed. For each galaxy, we derive the average PDR hydrogen density, nHn_{\rm H}, and intensity of the interstellar radiation field, in units of G0_0, and find G0_0/nHn_{\rm H} ratios ~0.1-50 cm3^3, with ULIRGs populating the upper end of the distribution. There is a relation between G0_0/nHn_{\rm H} and ΣIR\Sigma_{\rm IR}, showing a critical break at ΣIR\Sigma_{\rm IR}^{\star} ~ 5 x 1010^{10} Lsun/kpc2^2. Below ΣIR\Sigma_{\rm IR}^{\star}, G0_0/nHn_{\rm H} remains constant, ~0.32 cm3^3, and variations in ΣIR\Sigma_{\rm IR} are driven by the number density of star-forming regions within a galaxy, with no change in their PDR properties. Above ΣIR\Sigma_{\rm IR}^{\star}, G0_0/nHn_{\rm H} increases rapidly with ΣIR\Sigma_{\rm IR}, signaling a departure from the typical PDR conditions found in normal star-forming galaxies towards more intense/harder radiation fields and compact geometries typical of starbursting sources.Comment: 23 pages, 12 figures. Submitted to ApJ, including 2nd round of referee comments. Data tables can be found at: http://goals.ipac.caltech.edu/ and will also appear on the electronic version of the journa

    Reflections and projections on a decade of climate science

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    To mark the tenth anniversary of Nature Climate Change, we asked a selection of researchers across the broad range of climate change disciplines to share their thoughts on notable developments of the past decade, as well as their hopes and expectations for the coming years of discovery. Much has changed in the last 10 years since the Nature Climate Change inaugural issue in April 2011. The effects of climate change are now more apparent, global leaders have reached a climate agreement, and public awareness and engagement, particularly in the younger generation, continues to grow. Here, ten researchers discuss advances in their field, highlighting the progress and drawing attention to what still needs to be done

    Charge and Spin Structures of a dx2y2d_{x^2 - y^2} Superconductor in the Proximity of an Antiferromagnetic Mott Insulator

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    To the Hubbard model on a square lattice we add an interaction, WW, which depends upon the square of a near-neighbor hopping. We use zero temperature quantum Monte Carlo simulations on lattice sizes up to 16×1616 \times 16, to show that at half-filling and constant value of the Hubbard repulsion, the interaction WW triggers a quantum transition between an antiferromagnetic Mott insulator and a dx2y2d_{x^2 -y^2} superconductor. With a combination of finite temperature quantum Monte Carlo simulations and the Maximum Entropy method, we study spin and charge degrees of freedom in the superconducting state. We give numerical evidence for the occurrence of a finite temperature Kosterlitz-Thouless transition to the dx2y2d_{x^2 -y^2} superconducting state. Above and below the Kosterlitz-Thouless transition temperature, TKTT_{KT}, we compute the one-electron density of states, N(ω)N(\omega), the spin relaxation rate 1/T11/T_1, as well as the imaginary and real part of the spin susceptibility χ(q,ω)\chi(\vec{q},\omega). The spin dynamics are characterized by the vanishing of 1/T11/T_1 and divergence of Reχ(q=(π,π),ω=0)Re \chi(\vec{q} = (\pi,\pi), \omega = 0) in the low temperature limit. As TKTT_{KT} is approached N(ω)N(\omega) develops a pseudo-gap feature and below TKTT_{KT} Imχ(q=(π,π),ω)Im \chi(\vec{q} = (\pi,\pi), \omega) shows a peak at finite frequency.Comment: 46 pages (latex) including 14 figures in encapsulated postscript format. Submitted for publication in Phys. Rev.

    Allocation to highly sensitized patients based on acceptable mismatches results in low rejection rates comparable to non-sensitized patients

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    Whereas regular allocation avoids unacceptable mismatches on the donor organ, allocation to highly sensitized patients within the Eurotransplant Acceptable Mismatch (AM) program is based on the patient's HLA phenotype plus acceptable antigens. These are HLA antigens to which the patient never made antibodies, determined by extensive laboratory testing. AM patients have superior long-term graft survival compared to highly sensitized patients in regular allocation. Here, we questioned whether the AM program also results in lower rejection rates. From the PROCARE cohort, consisting of all Dutch kidney transplants 1995-2005, we selected deceased donor single transplants with minimum one HLA mismatch and determined the cumulative 6-month rejection incidence for patients in AM or regular allocation. Additionally, we determined the effect of minimal matching criteria of one HLA-B plus one HLA-DR, or two HLA-DR antigens on rejection incidence. AM patients showed significantly lower rejection rates than highly immunized patients in regular allocation, comparable to non-sensitized patients, independent of other risk factors for rejection. Contrasting to highly sensitized patients in regular allocation, minimal matching criteria did not affect rejection rates in AM patients. Allocation based on acceptable antigens leads to relatively low risk transplants for highly sensitized patients with rejection rates similar to non-immunized individuals. This article is protected by copyright. All rights reserved.</p

    High resolution mapping of a novel late blight resistance gene Rpi-avll, from the wild Bolivian species Solanum avilesii

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    Both Mexico and South America are rich in Solanum species that might be valuable sources of resistance (R) genes to late blight (Phytophthora infestans). Here, we focus on an R gene present in the diploid Bolivian species S. avilesii. The genotype carrying the R gene was resistant to eight out of 10 Phytophthora isolates of various provenances. The identification of a resistant phenotype and the generation of a segregating population allowed the mapping of a single dominant R gene, Rpi-avl1, which is located in an R gene cluster on chromosome 11. This R gene cluster is considered as an R gene “hot spot”, containing R genes to at least five different pathogens. High resolution mapping of the Rpi-avl1 gene revealed a marker co-segregating in 3890 F1 individuals, which may be used for marker assisted selection in breeding programs and for further cloning of Rpi-avl
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