993 research outputs found

    Physics based calibration of the Herschel/SPIRE bolometers

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    The bolometers (and readout circuitry) in the SPIRE instrument on the Herschel Space Observatory are among the best understood and well characterised of any sub‐mm astronomy instrument to date. SPIRE contains five arrays of NTD germanium spiderweb bolometers with up to 139 pixels per array. Their behaviour has been shown to be extremely stable as seen by repeated measurements in the years between initial array level and final instrument level tests, and can be described extremely well by a simple physical model (the ideal bolometer model). Calibration of the bolometers must take into account the non‐linear response when viewing bright sources, and the effect of fluctuations in the heat sink temperature. The simple and well‐understood behaviour of the detectors, coupled with the stable conditions expected in flight, mean that in contrast to previous sub‐mm instruments, physical models can be used to improve or possibly replace empirical calibration methods. We describe how this can be done, and use the large amount of data from ground measurements to show that we can use models to accurately calculate the absolute power detected by the bolometers

    Understanding the Herschel-SPIRE bolometers

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    Bolometers are very simple devices. In principle, the behaviour of a bolometer can be described by a simple model along with a small number of parameters. The SPIRE instrument for the Herschel Space Observatory contains five arrays of NTD germanium spiderweb bolometers containing up to 139 pixels. We show from characterisation measurements on the ground using the flight read-out system that the bolometers follow the ideal model extremely well, are very stable, and that the read-out system is sufficiently well behaved to take advantage of this. Calibration should be greatly simplified by being able to take advantage of this behaviour

    Preparation and Foliar Application of Oligochitosan - Nanosilica on the Enhancement of Soybean Seed Yield

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    Oligochitosan with weight average molecu-lar weight (Mw) of 5000 g/mol was prepared by gamma Co-60 radiation degradation of 4% chitosan solution containing 0.5% H2O2 at 21 kGy. Nanosilica with size of 10 – 30 nm was synthesized by calcination of acid treated rice husk at 700o C for 2 h. The mixture of 2% oligo-chitosan-2% nanosilica was prepared by dispersion of nanosilica in oligochitosan solution. Oligochitosan, nanosilica and their mixture were characterized by gel permeation chromatography (GPC), transmission electr-on microscopy (TEM), X-ray diffraction (XRD), energy dispersive x-ray spectroscopy (EDX), Ultraviolet-visible spectroscopy (UV-Vis), and Furrier transform infrared spectroscopy (FT-IR). Effect of foliar application of oli-gochitosan and oligochitosan-nanosilica on soybean seed yield was conducted in experimental field. Results indi-cated that soybean seed yield increased 10.5 and 17.0% for oligochitosan and oligochitosan-nanosilica, respect-tively for the control. Radiation degraded oligo-chitosan and its mixture with nanosilica can be potentially used for cultivation of soybean with enhanced seed yield

    Conquering hypertension in Vietnam-solutions at grassroots level: study protocol of a cluster randomized controlled trial

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    BACKGROUND: Vietnam has been experiencing an epidemiologic transition to that of a lower-middle income country with an increasing prevalence of non-communicable diseases. The key risk factors for cardiovascular disease (CVD) are either on the rise or at alarming levels in Vietnam, particularly hypertension (HTN). Inasmuch, the burden of CVD will continue to increase in the Vietnamese population unless effective prevention and control measures are put in place. The objectives of the proposed project are to evaluate the implementation and effectiveness of two multi-faceted community and clinic-based strategies on the control of elevated blood pressure (BP) among adults in Vietnam via a cluster randomized trial design. METHODS: Sixteen communities will be randomized to either an intervention (8 communities) or a comparison group (8 communities). Eligible and consenting adult study participants with HTN (n = 680) will be assigned to intervention/comparison status based on the community in which they reside. Both comparison and intervention groups will receive a multi-level intervention modeled after the Vietnam National Hypertension Program including education and practice change modules for health care providers, accessible reading materials for patients, and a multi-media community awareness program. In addition, the intervention group only will receive three carefully selected enhancements integrated into routine clinical care: (1) expanded community health worker services, (2) home BP self-monitoring, and (3) a storytelling intervention, which consists of interactive, literacy-appropriate, and culturally sensitive multi-media storytelling modules for motivating behavior change through the power of patients speaking in their own voices. The storytelling intervention will be delivered by DVDs with serial installments at baseline and at 3, 6, and 9 months after trial enrollment. Changes in BP will be assessed in both groups at several follow-up time points. Implementation outcomes will be assessed as well. DISCUSSION: Results from this full-scale trial will provide health policymakers with practical evidence on how to combat a key risk factor for CVD using a feasible, sustainable, and cost-effective intervention that could be used as a national program for controlling HTN in Vietnam. TRIAL REGISTRATION: ClinicalTrials.gov NCT03590691 . Registered on July 17, 2018. Protocol version: 6. Date: August 15, 2019

    Streptococcus suis, an Important Cause of Adult Bacterial Meningitis in Northern Vietnam

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    Streptococcus suis can cause severe systemic infection in adults exposed to infected pigs or after consumption of undercooked pig products. S. suis is often misdiagnosed, due to lack of awareness and improper testing. Here we report the first fifty cases diagnosed with S. suis infection in northern Viet Nam.In 2007, diagnostics for S. suis were set up at a national hospital in Hanoi. That year there were 43 S. suis positive cerebrospinal fluid samples, of which S. suis could be cultured in 32 cases and 11 cases were only positive by PCR. Seven patients were blood culture positive for S. suis but CSF culture and PCR negative; making a total of 50 patients with laboratory confirmed S. suis infection in 2007. The number of S. suis cases peaked during the warmer months.S. suis was commonly diagnosed as a cause of bacterial meningitis in adults in northern Viet Nam. In countries where there is intense and widespread exposure of humans to pigs, S. suis can be an important human pathogen

    BICEP: a large angular scale CMB polarimeter

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    We describe the design and expected performance of BICEP, a millimeter wave receiver designed to measure the polarization of the cosmic microwave background. BICEP uses an array of polarization sensitive bolometers operating at 100 and 150 GHz to measure polarized signals over a 20 degree field of view with 1 degree resolution. BICEP is designed with particular attention to systematic effects which can potentially degrade the polarimetric fidelity of the observations. BICEP is optimized to detect the faint signature of a primordial gravitational wave background which is a generic prediction of inflationary cosmologies

    Understanding the Herschel-SPIRE bolometers

    Get PDF
    Bolometers are very simple devices. In principle, the behaviour of a bolometer can be described by a simple model along with a small number of parameters. The SPIRE instrument for the Herschel Space Observatory contains five arrays of NTD germanium spiderweb bolometers containing up to 139 pixels. We show from characterisation measurements on the ground using the flight read-out system that the bolometers follow the ideal model extremely well, are very stable, and that the read-out system is sufficiently well behaved to take advantage of this. Calibration should be greatly simplified by being able to take advantage of this behaviour

    Physics based calibration of the Herschel/SPIRE bolometers

    Get PDF
    The bolometers (and readout circuitry) in the SPIRE instrument on the Herschel Space Observatory are among the best understood and well characterised of any sub‐mm astronomy instrument to date. SPIRE contains five arrays of NTD germanium spiderweb bolometers with up to 139 pixels per array. Their behaviour has been shown to be extremely stable as seen by repeated measurements in the years between initial array level and final instrument level tests, and can be described extremely well by a simple physical model (the ideal bolometer model). Calibration of the bolometers must take into account the non‐linear response when viewing bright sources, and the effect of fluctuations in the heat sink temperature. The simple and well‐understood behaviour of the detectors, coupled with the stable conditions expected in flight, mean that in contrast to previous sub‐mm instruments, physical models can be used to improve or possibly replace empirical calibration methods. We describe how this can be done, and use the large amount of data from ground measurements to show that we can use models to accurately calculate the absolute power detected by the bolometers

    CMB polarimetry with BICEP: instrument characterization, calibration, and performance

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    BICEP is a ground-based millimeter-wave bolometric array designed to target the primordial gravity wave signature on the polarization of the cosmic microwave background (CMB) at degree angular scales. Currently in its third year of operation at the South Pole, BICEP is measuring the CMB polarization with unprecedented sensitivity at 100 and 150 GHz in the cleanest available 2% of the sky, as well as deriving independent constraints on the diffuse polarized foregrounds with select observations on and off the Galactic plane. Instrument calibrations are discussed in the context of rigorous control of systematic errors, and the performance during the first two years of the experiment is reviewed.Comment: 12 pages, 15 figures, updated version of a paper accepted for Millimeter and Submillimeter Detectors and Instrumentation for Astronomy IV, Proceedings of SPIE, 7020, 200

    Las políticas de reequilibro territorial e innovación institucional en Madrid, 2015-2019

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    Lograr un mejor reparto de los recursos materiales es una tarea inseparable de una transformación institucional dirigida a un mejor reparto del poder y de la capacidad de decisión. Es preciso reconfigurar las instituciones para redefinir la relación entre estas y la ciudadanía. El espacio de cooperación entre las instituciones públicas y la sociedad civil organizada es un terreno privilegiado para lograr esa reconfiguración institucional. El Fondo de Reequilibrio Territorial se concibe como un primer paso en ese complejo camino y se relaciona con el proceso de descentralización y con el concepto de cooperación público-social. Debe entenderse en relación con otros desarrollos institucionales, como el Consejo Coordinador de los Distritos o los Foros Locales. Una tarea de estas características no puede realizarse desde un solo espacio institucional y en un solo mandato, pero en todo caso debe hacerse contando con la firme voluntad y dirección política del equipo de gobierno que quiera desempeñarla. El gobierno es una herramienta formidable para emprender un proceso de reequilibrio territorial, pero aun cuando no hay en el mismo voluntad política en este sentido existen posibilidades para estimular o condicionar la voluntad del equipo de gobierno: articular un amplio pacto entre los actores políticos, sociales, económicos, académicos, etc. que ponga la cuestión en el centro de la agenda política y eleve hasta lo impagable el coste político de seguir dando la espalda a una cuestión crucial para el futuro de la democracia.Lograr un mejor reparto de los recursos materiales es una tarea inseparable de una transformación institucional dirigida a un mejor reparto del poder y de la capacidad de decisión. Es preciso reconfigurar las instituciones para redefinir la relación entre estas y la ciudadanía. El espacio de cooperación entre las instituciones públicas y la sociedad civil organizada es un terreno privilegiado para lograr esa reconfiguración institucional.El Fondo de Reequilibrio Territorial se concibe como un primer paso en ese complejo camino y se relaciona con el proceso de descentralización y con el concepto de cooperación público-social. Debe entenderse en relación con otros desarrollos institucionales, como el Consejo Coordinador de los Distritos o los Foros Locales. Una tarea de estas características no puede realizarse desde un solo espacio institucional y en un solo mandato, pero en todo caso debe hacerse contando con la firme voluntad y dirección política del equipo de gobierno que quiera desempeñarla. El gobierno es una herramienta formidable para emprender un proceso de reequilibrio territorial, pero aun cuando no hay en el mismo voluntad política en este sentido existen posibilidades para estimular o condicionar la voluntad del equipo de gobierno: articular un amplio pacto entre los actores políticos, sociales, económicos, académicos, etc. que ponga la cuestión en el centro de la agenda política y eleve hasta lo impagable el coste político de seguir dando la espalda a una cuestión crucial para el futuro de la democracia
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