9,952 research outputs found

    Are there socioeconomic gradients in stage and grade of breast cancer at diagnosis? Cross sectional analysis of UK cancer registry data

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    Socioeconomic gradients in uptake of breast cancer screening in the United Kingdom should, intuitively, lead to socioeconomic gradients in disease progression at diagnosis. However, studies have found little evidence of such an effect. Although this could be interpreted as evidence that socioeconomic gradients in uptake of screening do not have clinically important consequences, all of the published studies have used data from before (pre-1988) or during the early stages (1988-95) of implementation of the national breast cancer screening programme. We investigated the relation between socioeconomic position and progression of breast cancer at diagnosis by using recent data from the Northern and Yorkshire Cancer Registry and Information Service (NYCRIS), which is estimated to achieve around 93% ascertainment

    Survivor Funds

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    This Article explains how to create “survivor funds”—short-term investment funds that would pay more to those investors who live until the end of the fund’s term than to those who die before then. For example, instead of just investing in a ten-year bond and dividing the proceeds among the investors at the end of the bond term, a survivor fund would invest in that ten-year bond but divide the proceeds only among those who survived the full ten years. These survivor funds would be attractive investments because the survivors would get a greater return on their investments, while the decedents, for obvious reasons, would not care. Survivor funds would work like short-term tontines. Basically, a tontine is a financial product that combines features of an annuity and a lottery. In a simple tontine, a group of investors pools their money together to buy a portfolio of investments, and, as investors die, their shares are forfeited, often with the entire fund going to the last survivor. For example, imagine that ten 65-year-old men each contribute 1000toafundthatbuysalargediamondfor1000 to a fund that buys a large diamond for 10,000 and that the men agree that the last “survivor will get the diamond. Accordingly, after the ninth man dies, the tenth man gets the diamond, and he can keep it or sell it. Of course, the survivor principle—that the share of each, at death, is enjoyed by the survivors—can be used to design financial products that would benefit multiple survivors, not just the last survivor. For example, elsewhere, we showed how tontines could be used to create so-called “tontine annuities” and “tontine pensions” that would benefit lots of retirees. In this Article, we show how the survivor principle can be used to create survivor funds that would only make payments to those who survive for a specified number of years

    Substructure: Clues to the Formation of Clusters of Galaxies

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    We have examined the spatial distribution of substructure in clusters of galaxies using Einstein X-ray observations. Subclusters are found to have a markedly anisotropic distribution that reflects the surrounding matter distribution on supercluster scales. Our results suggest a picture in which cluster formation proceeds by mergers of subclusters along large-scale filaments. The implications of such an anisotropic formation process for the shapes, orientations and kinematics of clusters are discussed briefly.Comment: 7 pages, uuencoded compressed postscript. To appear in ApJ Letters (September 20, 1995 issue

    The Disturbed 17 keV Cluster Associated with the Radio Galaxy 3C 438

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    We present results from a {\em Chandra} observation of the cluster gas associated with the FR II radio galaxy 3C 438. This radio galaxy is embedded within a massive cluster with gas temperature \sim17 keV and bolometric luminosity of 6×1045\times10^{45} ergs s1^{-1}. It is unclear if this high temperature represents the gravitational mass of the cluster, or if this is an already high (\sim 11 keV) temperature cluster that has been heated transiently. We detect a surface brightness discontinuity in the gas that extends \sim600 kpc through the cluster. The radio galaxy 3C 438 is too small (\sim110 kpc across) and too weak to have created this large disturbance in the gas. The discontinuity must be the result of either an extremely powerful nuclear outburst or the major merger of two massive clusters. If the observed features are the result of a nuclear outburst, it must be from an earlier epoch of unusually energetic nuclear activity. However, the energy required (1063\sim10^{63} ergs) to move the gas on the observed spatial scales strongly supports the merger hypothesis. In either scenario, this is one of the most extreme events in the local Universe.Comment: 13 pages, 4 figures, 1 table - accepted for publication in the Astrophysical Journal Letter

    Helper activity is required for the in vivo generation of cytotoxic T lymphocytes

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    B6.T1a(a) (Qa-1(a)) mice that are primed in vivo and restimulated in vitro with Qa-1 congenic spleen cells from B6 (Qa-1(b)) animals are unable to generate anti-Qa-1(b) cytotoxic T lymphocytes (CTL). This nonresponsive pattern was observed regardless of the route of immunization or the time of testing in vitro. Although B6.T1a(a) mice are nonresponders to Qa-1(b) when presented on B6 cells, these mice can generate anti-Qa-1(b) CTL when primed in vivo with Qa-1 and H-Y alloantigens (females primed with B6 male cells) or Qa-1 and minor-H- alloantigens (primed with sex-matched A.BY cells). Therefore, the inability to generate anti-Qa-1(b) CTL is due to a lack of helper or accessory antigens on B6 immunizing cells obligatory during in vivo priming, rather than an absence of anti-Qa-1(b) CTL precursors (CTL-P). Demonstration that the additional determinants required during in vivo priming actually function as carrier or helper determinants was shown by the requirement for linked recognition of Qa-1 and the helper determinants (H-Y) in vivo, and the fact that H-Y was not present on susceptible target ceils. Animals primed in vivo with H-Y only could not generate anti-Qa-1 CTL activity when challenged in vitro with both Qa-1 and H-Y, indicating that recognition of the helper determinant causes in vivo priming of CTL-P rather than generating helper activity that might activate unprimed CTL-P in vitro. Whereas unprimed peripheral CTL-P require the presence of both Qa-1 (CTL) and H-Y (helper) determinants for successful in vivo priming, helper determinants were not required in vitro because primed CTL-P from B6.T1a(a) mice could be driven to CTL in vitro using sex-matched B6 stimulator cells. The generation of anti-Qa-1(b) CTL is under immune response (Ir) gene control because F(1) mice, obtained by crossing responder A/J with nonresponder B6.T1a(a) animals, generated CTL to the Qa-1(b) alloantigen when presented on B6 spleen cells. Progeny testing of backcross mice further demonstrated that the Ir gene(s) is linked to the H-2 complex. These data indicate that an H-2-linked Ir gene controls the recognition of helper determinants required for CTL priming in vivo. These helper determinants can be distinguished from CTL determinants and both must be recognized together for successful priming of CTL-P

    Influence of skunk removal on nest success and breeding populations of upland nesting ducks in the lower Flathead Valley Montana

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    The 30/20 GHz flight experiment system, phase 2. Volume 2: Experiment system description

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    A detailed technical description of the 30/20 GHz flight experiment system is presented. The overall communication system is described with performance analyses, communication operations, and experiment plans. Hardware descriptions of the payload are given with the tradeoff studies that led to the final design. The spacecraft bus which carries the payload is discussed and its interface with the launch vehicle system is described. Finally, the hardwares and the operations of the terrestrial segment are presented

    The 30/20 GHz flight experiment system, phase 2. Volume 1: Executive summary

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    Summary information on the final communication system design, communication payload, space vehicle, and development plan for the 30/20 GHz flight experiment will be installed on the LEASAT spacecraft which will be placed into orbit from the space shuttle cargo bay. The communication concept has two parts: a truck service and a customer premise service (CPS). The trucking system serves four spot beams which are interconnected in a satellite switched time division multiple access mode by an IF switch matrix. The CPS covers two large areas of the eastern United States with a pair of scanning beams

    The 30/20 GHz flight experiment system, phase 2. Volume 3: Experiment system requirement document

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    An approach to the requirements document to be used to procure the system by NASA is presented. The basic approach is similar to the requirements document used in the commercial communication satellite. Enough detail requirements are given to define the system without tight constraints

    Propagation of the phase of solar modulation

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    The phase of the 11 year galactic cosmic ray variation, due to a varying rate of emission of long lived propagating regions of enhanced scattering, travels faster than the scattering regions themselves. The radial speed of the 11 year phase in the quasi-steady, force field approximation is exactly twice the speed of the individual, episodic decreases. A time dependent, numerical solution for 1 GeV protons at 1 and 30 Au gives a phase speed which is 1.85 times the propagation speed of the individual decreases
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