23,586 research outputs found

    The On The Fly Imaging Technique

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    The On-The-Fly (OTF) imaging technique enables single-dish radio telescopes to construct images of small areas of the sky with greater efficiency and accuracy. This paper describes the practical application of the OTF imaging technique. By way of example the implementation of the OTF imaging technique at the NRAO 12 Meter Telescope is described. Specific requirements for data sampling, image formation, and Doppler correction are discussed.Comment: 10 pages, 13 figures, accepted A&

    Giant viscosity enhancement in a spin-polarized Fermi liquid

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    The viscosity is measured for a Fermi liquid, a dilute 3^3He-4^4He mixture, under extremely high magnetic field/temperature conditions (B≤14.8B \leq 14.8 T, T≥1.5T \geq 1.5 mK). The spin splitting energy μB\mu B is substantially greater than the Fermi energy kBTFk_B T_F; as a consequence the polarization tends to unity and s-wave quasiparticle scattering is suppressed for T≪TFT \ll T_F. Using a novel composite vibrating-wire viscometer an enhancement of the viscosity is observed by a factor of more than 500 over its low-field value. Good agreement is found between the measured viscosity and theoretical predictions based upon a tt-matrix formalism.Comment: 4 pages, 4 figure

    Fabrication of glass gas cells for the HALOE and MAPS satellite experiments

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    The Halogen Occultation Experiment (HALOE) and the Measurement of Air Pollution from Satellites (MAPS) experiment are satellite-borne experiments which measure trace constituents in the Earth's atmosphere. The instruments which obtain the data for these experiments are based on the gas filter correlation radiometer measurement technique. In this technique, small samples of the gases of interest are encapsulated in glass cylinders, called gas cells, which act as very selective optical filters. This report describes the techniques employed in the fabrication of the gas cells for the HALOE and MAPS instruments. Details of the method used to fuse the sapphire windows (required for IR transmission) to the glass cell bodies are presented along with detailed descriptions of the jigs and fixtures used during the assembly process. The techniques and equipment used for window inspection and for pairing the HALOE windows are discussed. Cell body materials and the steps involved in preparing the cell bodies for the glass-to-sapphire fusion process are given

    On the topological entropy of saturated sets

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    The role of parental and child physical and mental health on behavioural and emotional adjustment in mid-childhood: a comparison of two generations of British children born 30 years apart

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    Poor physical health and behavioural and emotional problems in childhood have a lasting impact on well-being in adolescence and adulthood. Here we address the relationship between poor parent and child physical and mental health in early childhood (age 5) and conduct, hyperactivity and emotional problems in mid-childhood (age 10/11). We compare results across two generations of British children born 30 years apart in 1970 (n = 15,856) and 2000/2 (16,628). We take advantage of rich longitudinal birth cohort data and establish that a child’s own poor health was associated with conduct, hyperactivity and emotional problems in mid-childhood in both generations, and that with the exception of conduct problems in the 1970 cohort these relationships remained when family socio-economic status and individual characteristics were accounted for. Poor maternal mental health was similarly associated with conduct, hyperactivity and emotional problems in both generations; poor parental physical health with a child having later hyperactivity and emotional problems in the younger generation. Results also indicated that earlier behaviour problems had more influence on later problems for children in the more recent cohort. Given the increasing proportion of children and adolescents with mental health problems and that socio-economic disadvantage increases physical and mental well-being concerns within families, policy solutions must consider the holistic nature of a child’s family environment to prevent some children experiencing a ‘double whammy’ of disadvantage. The early years provide the best opportunity to promote children’s resilience and well-being and minimise the development of entrenched negative behaviours and their subsequent costs to society

    Targeting the Mitochondrial Permeability Transition Pore in Traumatic Central Nervous System Injury

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    The mitochondrion serves many functions in the central nervous system (CNS) and other organs beyond the well-recognized role of adenosine triphosphate (ATP) production. This includes calcium-dependent cell signaling, regulation of gene expression, synthesis and release of cytotoxic reactive oxygen species, and the release of cytochrome c and other apoptotic cell death factors. Traumatic injury to the CNS results in a rapid and, in some cases, sustained loss of mitochondrial function. One consequence of compromised mitochondrial function is induction of the mitochondrial permeability transition (mPT) state due to formation of the cyclosporine A sensitive permeability transition pore (mPTP). In this mini-review, we summarize evidence supporting the involvement of the mPTP as a mediator of mitochondrial and cellular demise following CNS traumatic injury and discuss the beneficial effects and limitations of the current ex-perimental strategies targeting the mPTP

    Influence of sodium chloride reduction and replacement with potassium chloride based salts on the sensory and physico-chemical characteristics of pork sausage patties

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    This study evaluated the effects of sodium chloride reduction and replacement with potassium chloride or modified potassium chloride based salts using a weight or molar equivalent basis on the sensory and physicochemical properties of pork sausage patties. Three independent replications of pork sausage patties were manufactured to compare five treatments: full sodium, reduced sodium, modified potassium chloride weight based replacement, modified potassium chloride molar based replacement, and standard potassium chloride weight based replacement. Salt replacement did not affect (P \u3e 0.05) moisture, protein, fat, textural properties, lipid oxidation, or redness. Sausage patties with modified potassium chloride were more acceptable than those with standard potassium chloride (P \u3c 0.001). Using modified potassium chloride replaced on a molar equivalent basis resulted in samples with more similar sensory characteristics to the full sodium control than replacement on a weight equivalent basis. The use of modified potassium chloride reduced sodium and improved sodium:potassium ratios while other changes in composition or physico-chemical characteristics were minimal
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