1,671 research outputs found

    Metamaterial metal-based bolometers

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    We demonstrate metamaterial metal-based bolometers, which take advantage of resonant absorption in that a spectral and/or polarization filter can be built into the bolometer. Our proof-of-principle gold-nanostructure-based devices operate around 1.5 \mum wavelength and exhibit room-temperature time constants of about 134 \mus. The ultimate detectivity is limited by Johnson noise, enabling room-temperature detection of 1 nW light levels within 1 Hz bandwidth. Graded bolometer arrays might allow for integrated spectrometers with several octaves bandwidth without the need for gratings or prisms and for integrated polarization analysis without external polarization optics

    Constraints on Light Pseudoscalars Implied by Tests of the Gravitational Inverse-Square Law

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    The exchange of light pseudoscalars between fermions leads to a spin-independent potential in order g^4, where g is the Yukawa pseudoscalar-fermion coupling constant. This potential gives rise to detectable violations of both the weak equivalence principle (WEP) and the gravitational inverse-square law (ISL), even if g is quite small. We show that when previously derived WEP constraints are combined with those arisingfrom ISL tests, a direct experimental limit on the Yukawa coupling of light pseudoscalars to neutrons can be inferred for the first time (g_n^2/4pi < 1.6 \times 10^-7), along with a new (and significantly improved) limit on the coupling of light pseudoscalars to protons.Comment: 12 pages, Revtex, with 1 Postscript figure (submitted to Physical Review Letters

    EC57-702 Nebraska Minimum Standards for Artificially Gravel Packed Irrigation Wells

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    Extension Circular 57-702 is about the Nebraska minimum standards for artificially gravel packed irrigation wells, and explaina the purpose of properly constructed irrigation that will last decades

    EC57-702 Nebraska Minimum Standards for Artificially Gravel Packed Irrigation Wells

    Get PDF
    Extension Circular 57-702 is about the Nebraska minimum standards for artificially gravel packed irrigation wells, and explaina the purpose of properly constructed irrigation that will last decades

    Nebraska Minimum Standards for Artificially Gravel Packed Irrigation Wells

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    Peritoneal Dialysis Tailored to Pediatric Needs

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    Consideration of specific pediatric aspects is essential to achieve adequate peritoneal dialysis (PD) treatment in children. These are first of all the rapid growth, in particular during infancy and puberty, which must be accompanied by a positive calcium balance, and the age dependent changes in body composition. The high total body water content and the high ultrafiltration rates required in anuric infants for adequate nutrition predispose to overshooting convective sodium losses and severe hypotension. Tissue fragility and rapid increases in intraabdominal fat mass predispose to hernia and dialysate leaks. Peritoneal equilibration tests should repeatedly been performed to optimize individual dwell time. Intraperitoneal pressure measurements give an objective measure of intraperitoneal filling, which allow for an optimized dwell volume, that is, increased dialysis efficiency without increasing the risk of hernias, leaks, and retrofiltration. We present the concept of adapted PD, that is, the combination of short dwells with low fill volume to promote ultrafiltration and long dwells with a high fill volume to improve purification within one PD session. The use of PD solutions with low glucose degradation product content is recommended in children, but unfortunately still not feasible in many countries
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