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Sample records for background radiation early

  1. The Cosmic Microwave Background Radiation - A Unique Window on the Early Universe

    NASA Technical Reports Server (NTRS)

    Hinshaw, Gary F.

    2009-01-01

    The cosmic microwave background radiation is the remnant heat from the Big Bang. It provides us with a unique probe of conditions in the early universe, long before any organized structures had yet formed. The anisotropy in the radiation's brightness yields important clues about primordial structure and additionally provides a wealth of information about the physics of the early universe. Within the framework of inflationary dark matter models, observations of the anisotropy on sub-degree angular scales reveals the signatures of acoustic oscillations of the photon-baryon fluid at a redshift of approximately 1100. Data from the first five years of operation of the Wilkinson Microwave Anisotropy Probe (WMAP) satellite provide detailed full-sky maps of the cosmic microwave background temperature and polarization anisotropy. Together, the data provide a wealth of cosmological information, including the age of the universe, the epoch when the first stars formed, and the overall composition of baryonic matter, dark matter, and dark energy. The results also provide constraints on the period of inflationary expansion in the very first moments of time. WMAP, part of NASA's Explorers program, was launched on June 30, 2001. The WMAP satellite was produced in a partnership between the Goddard Space Flight Center and Princeton University. The WMAP team also includes researchers at the Johns Hopkins University; the Canadian Institute of Theoretical Astrophysics; University of Texas; Oxford University; University of Chicago; Brown University; University of British Columbia; and University of California, Los Angeles.

  2. The Cosmic Microwave Background Radiation - A Unique Window on the Early Universe

    NASA Technical Reports Server (NTRS)

    Hinshaw, Gary F.

    2009-01-01

    The cosmic microwave background radiation is the remnant heat from the Big Bang. It provides us with a unique probe of conditions in the early universe, long before any organized structures had yet formed. The anisotropy in the radiation's brightness yields important clues about primordial structure and additionally provides a wealth of information about the physics of the early universe. Within the framework of inflationary dark matter models, observations of the anisotropy on sub-degree angular scales reveals the signatures of acoustic oscillations of the photon-baryon fluid at a redshift of approx. 1100. Data from the first five years of operation of the Wilkinson Microwave Anisotropy Probe (WMAP) satellite provide detailed full-sky maps of the cosmic microwave background temperature and polarization anisotropy. Together, the data provide a wealth of cosmological information, including the age of the universe, the epoch when the first stars formed, and the overall composition of baryonic matter, dark matter, and dark energy. The results also provide constraints on the period of inflationary expansion in the very first moments of time.

  3. The Cosmic Microwave Background Radiation - A Unique Window on the Early Universe

    NASA Technical Reports Server (NTRS)

    Hinshaw, Gary F.

    2008-01-01

    The cosmic microwave background radiation is the remnant heat from the Big Bang. It provides us with a unique probe of conditions in the early universe, long before any organized structures had yet formed. The anisotropy in the radiation's brightness yields important clues about primordial structure and additionally provides a wealth of information about the physics of the early universe. Within the framework of inflationary dark matter models, observations of the anisotropy on sub-degree angular scales reveals the signatures of acoustic oscillations of the photon-baryon fluid at a redshift of approximately 1100. Data from the first five years of operation of the Wilkinson Microwave Anisotropy Probe (WMAP) satellite provide detailed full-sky maps of the cosmic microwave background temperature and polarization anisotropy. Together, the data provide a wealth of cosmological information, including the age of the universe, the epoch when the first stars formed, and the overall composition of baryonic matter, dark matter, and dark energy. The results also provide constraints on the period of inflationary expansion in the very first moments of time. WMAP, part of NASA's Explorers program, was launched on June 30, 2001. The WMAP satellite was produced in a partnership between the Goddard Space Flight Center and Princeton University. The WMAP team also includes researchers at Johns Hopkins University; the Canadian Institute of Theoretical Astrophysics; University of Texas; Oxford University; University of Chicago; Brown university; University of British Columbia; and University of California, Los Angeles.

  4. The Cosmic Microwave Background Radiation-A Unique Window on the Early Universe

    NASA Technical Reports Server (NTRS)

    Hinshaw, Gary

    2010-01-01

    The cosmic microwave background radiation is the remnant heat from the Big Bang. It provides us with a unique probe of conditions in the early universe, long before any organized structures had yet formed. The anisotropy in the radiation's brightness yields important clues about primordial structure and additionally provides a wealth of information about the physics of the early universe. Within the framework of inflationary dark matter models, observations of the anisotropy on sub-degree angular scales reveals the signatures of acoustic oscillations of the photon-baryon fluid at a redshift of 11 00. Data from the first seven years of operation of the Wilkinson Microwave Anisotropy Probe (WMAP) satellite provide detailed full-sky maps of the cosmic microwave background temperature and polarization anisotropy. Together, the data provide a wealth of cosmological information, including the age of the universe, the epoch when the first stars formed, and the overall composition of baryonic matter, dark matter, and dark energy. The results also provide constraints on the period of inflationary expansion in the very first moments of time. WMAP, part of NASA's Explorers program, was launched on June 30, 2001. The WMAP satellite was produced in a partnership between the Goddard Space Flight Center and Princeton University. The WMAP team also includes researchers at the Johns Hopkins University; the Canadian Institute of Theoretical Astrophysics; University of Texas; Oxford University; University of Chicago; Brown University; University of British Columbia; and University of California, Los Angeles.

  5. Observing the Cosmic Microwave Background Radiation: A Unique Window on the Early Universe

    NASA Technical Reports Server (NTRS)

    Hinshaw, Gary; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    The cosmic microwave background radiation is the remnant heat from the Big Bang. It provides us with a unique probe of conditions in the early universe, long before any organized structures had yet formed. The anisotropy in the radiation's brightness yields important clues about primordial structure and additionally provides a wealth of information about the physics,of the early universe. Within the framework of inflationary dark matter models observations of the anisotropy on sub-degree angular scales will reveal the signatures of acoustic oscillations of the photon-baryon fluid at a redshift of approx. 1100. The validity of inflationary models will be tested and, if agreement is found, accurate values for most of the key cosmological parameters will result. If disagreement is found, we will need to rethink our basic ideas about the physics of the early universe. I will present an overview of the physical processes at work in forming the anisotropy and discuss what we have already learned from current observations. I will conclude with a brief overview of the recently launched Microwave Anisotropy Probe (MAP) mission which will observe the anisotropy over the full sky with 0.21 degree angular resolution. At the time of this meeting, MAP will have just arrived at the L2 Lagrange point, marking the start of its observing campaign. The MAP hardware is being produced by Goddard in partnership with Princeton University.

  6. Diffuse UV Background Radiation

    NASA Astrophysics Data System (ADS)

    Conn Henry, Richard; Murthy, J.

    2012-01-01

    The diffuse UV sky is expected to glow with significant amounts of starlight that is scattered from the interstellar dust. The albedo and scattering pattern of the dust in the ultraviolet are both well established, and are both fairly independent of wavelength from 912 Å to 3000 Å. We present 1943 Voyager spectra of the diffuse cosmic background radiation from 500 Å to 1200 Å, and we compare their brightnesses, and their distribution on the sky, to those observed (Murthy et al., ApJ 724, 1389, 2010) from the GALEX mission at longer wavelengths (1530 Å). Significant differences appear, suggesting that background radiation components in addition to dust-scattered starlight may be present in both spectral regions.

  7. The cosmic microwave background radiation

    NASA Technical Reports Server (NTRS)

    Silk, J.

    1981-01-01

    Because angular anisotropies and spectral distortions of the cosmic microwave background radiation are judged to be inevitable at some level, in a realistic cosmological model, the evidence for spectral distortions and its theoretical implications are described. The evidence for anisotropy is then discussed, and theoretical predictions of radiation anisotropy are summarized and compared with the data available. It is found that spectral distortions at the 3-sigma level near the peak of the blackbody spectrum, although inconsistent with the predicted distortions due to Compton scattering in the early universe, are elegantly interpreted in terms of radiation from an early, pregalactic generation of massive stars which had been thermalized by a modest amount of dust at high redshift. The quadrupole anisotropy at the 4-sigma level is most simply interpreted in terms of the large-scale structure of the universe.

  8. Ultraviolet Background Radiation

    NASA Astrophysics Data System (ADS)

    Henry, R. C.; Murthy, J.

    1993-12-01

    The UVX experiment was carried on the Space Shuttle Columbia between 1986 January 12 and 19 (STS-61C). Several ultraviolet spectrometers were used to obtain measurements of the diffuse ultraviolet background at 8 locations in the sky. We have reanalysed the UVX measurements of the surface brightness of the diffuse ultraviolet background above b = 40 using the dust-scattering model of Onaka & Kodaira (1991), which explicitly takes into account the variation of the source function with galactic longitude. The range of allowed values of interstellar grain albedoJa, and scattering asymmetry parameter g, is considerably expanded over those of a previous analysis. The new chi square probability contours come close to, but do not include, the values of a and g found for the interstellar grains by Witt et al. (1992) using the Ultraviolet Imaging Telescope (UIT) on the Astro mission. If we hypothesize in additon to the dust-scattered light an extragalactic component, of 300 1 100 photons cm-2 s-1 sr-1 A-1, attenuated by a cosecant b law, the new reduction of the UVX data gives complete consistency with the Witt et al. determination of the optical parameters of the grains in the ultraviolet. This work was supported by United States Air Force Contract F19628-93-K-0004, and by National Aeronautics and Space Administration grant NASA NAG5-619. We are grateful for the encouragement of Dr. Stephan Price, and we thank Dr. L. Danly for information. Onaka, T., & Kodaira, K. 1991, ApJ, 379, 532 Witt, A. N., Petersohn, J. K., Bohlin, R. C., O'Connell, R. W., Roberts, M. S., Smith, A. M., & Stecher, T. P. 1992, ApJ, 395, L5

  9. Teaching about Natural Background Radiation

    ERIC Educational Resources Information Center

    Al-Azmi, Darwish; Karunakara, N.; Mustapha, Amidu O.

    2013-01-01

    Ambient gamma dose rates in air were measured at different locations (indoors and outdoors) to demonstrate the ubiquitous nature of natural background radiation in the environment and to show that levels vary from one location to another, depending on the underlying geology. The effect of a lead shield on a gamma radiation field was also…

  10. Diffuse Cosmic Infrared Background Radiation

    NASA Technical Reports Server (NTRS)

    Dwek, Eli

    2002-01-01

    The diffuse cosmic infrared background (CIB) consists of the cumulative radiant energy released in the processes of structure formation that have occurred since the decoupling of matter and radiation following the Big Bang. In this lecture I will review the observational data that provided the first detections and limits on the CIB, and the theoretical studies explaining the origin of this background. Finally, I will also discuss the relevance of this background to the universe as seen in high energy gamma-rays.

  11. Teaching about natural background radiation

    NASA Astrophysics Data System (ADS)

    Al-Azmi, Darwish; Karunakara, N.; Mustapha, Amidu O.

    2013-07-01

    Ambient gamma dose rates in air were measured at different locations (indoors and outdoors) to demonstrate the ubiquitous nature of natural background radiation in the environment and to show that levels vary from one location to another, depending on the underlying geology. The effect of a lead shield on a gamma radiation field was also demonstrated to emphasize the important role of shielding in radiation protection. The measurements were carried out with a Geiger-Muller (GM)-based dosimeter and a NaI scintillation gamma-ray spectrometer, which are normally available in physics laboratories. Radioactivity in household materials was demonstrated using a gas mantle as an example.

  12. Early results from the MIT millimeter and sub-millimeter balloon-borne anisotropy measurement. [of cosmic microwave background radiation

    NASA Technical Reports Server (NTRS)

    Meyer, Stephan S.; Cheng, Edward S.; Page, Lyman A.

    1991-01-01

    The MIT balloon-borne bolometric search for Cosmic Microwave Background Radiation (CMBR) anisotropies places the most stringent constraints to date on fluctuations in the CMBR. Four maps of half of the Northern Hemisphere at 1.8, 1.1, 0.63 and 0.44 mm wavelength, have a beam size of 3.8 deg with a 1 sigma sensitivity of less than 0.1 mK (thermodynamic) per FOV in each of the first two channels. Analysis of the sky map at 1.8 mm wavelength using a likelihood ratio test for galactic latitudes of 15 deg and greater yields a 95 percent confidence level (CL) upper limit on fluctuations of the CMBR at DeltaT/T less than or equal to 1.6 x 10 exp -5 with a statistical power of 92 percent for Gaussian fluctuations at a correlation angle of 13 deg. Between 3 deg and 22 deg, the upper limit for fluctuations is DeltaT/T less than or equal to 4.0 x 10 exp -5 (95 percent CL).

  13. DarkLight radiation backgrounds

    SciTech Connect

    Kalantarians, Narbe

    2013-11-01

    We report measurements of photon and neutron radiation levels observed while transmitting a 0.43 MW electron beam through millimeter-sized apertures and during beam-on, but accelerating gradient RF-on, operation. These measurements were conducted at the Free-Electron Laser (FEL) facility of the Jefferson National Accelerator Laboratory (JLab) using a 100 MeV electron beam from an energy-recovery linear accelerator. The beam was directed successively through 6 mm, 4 mm, and 2 mm diameter apertures of length 127 mm in aluminum at a maximum current of 4.3 mA (430 kW beam power). This study was conducted to characterize radiation levels for experiments that need to operate in this environment, such as the proposed DarkLight Experiment. We find that sustained transmission of a 430 kW CW beam through a 2 mm aperture is feasible with manageable beam-related backgrounds. We also find that during beam-off, RF-on operation, field emission inside the niobium cavities of the accelerator cryomodules is the primary source of ambient radiation.

  14. Interpretation of observed cosmic microwave background radiation

    NASA Technical Reports Server (NTRS)

    Pollaine, S.

    1978-01-01

    The Alfven and Mendis (1977) conclusion that dust grains in galaxies render the universe opaque to cosmic microwave background at a red shift ratio equal to 40 is challenged by a calculation of the opacity of galactic dust grains to the microwave background radiation from the time of decoupling at emission red shift ratio equal to 1500 to the present in the standard big bang model. In the present calculation, evolutionary effects on grain opacity and abundance are estimated. At wavelengths used in studying the microwave background, the optical depth of the grains is found to be 0.18 when the deceleration parameter equals 0.03, and 0.05 when the deceleration parameter equals 0.5. The results indicate that microwave background can provide information on an early dense phase of the universe.

  15. The cosmic microwave background radiation

    NASA Technical Reports Server (NTRS)

    Silk, Joseph

    1992-01-01

    A review the implications of the spectrum and anisotropy of the cosmic microwave background for cosmology. Thermalization and processes generating spectral distortions are discussed. Anisotropy predictions are described and compared with observational constraints. If the evidence for large-scale power in the galaxy distribution in excess of that predicted by the cold dark matter model is vindicated, and the observed structure originated via gravitational instabilities of primordial density fluctuations, the predicted amplitude of microwave background anisotropies on angular scales of a degree and larger must be at least several parts in 10 exp 6.

  16. A review on natural background radiation

    PubMed Central

    Shahbazi-Gahrouei, Daryoush; Gholami, Mehrdad; Setayandeh, Samaneh

    2013-01-01

    The world is naturally radioactive and approximately 82% of human-absorbed radiation doses, which are out of control, arise from natural sources such as cosmic, terrestrial, and exposure from inhalation or intake radiation sources. In recent years, several international studies have been carried out, which have reported different values regarding the effect of background radiation on human health. Gamma radiation emitted from natural sources (background radiation) is largely due to primordial radionuclides, mainly 232Th and 238U series, and their decay products, as well as 40K, which exist at trace levels in the earth's crust. Their concentrations in soil, sands, and rocks depend on the local geology of each region in the world. Naturally occurring radioactive materials generally contain terrestrial-origin radionuclides, left over since the creation of the earth. In addition, the existence of some springs and quarries increases the dose rate of background radiation in some regions that are known as high level background radiation regions. The type of building materials used in houses can also affect the dose rate of background radiations. The present review article was carried out to consider all of the natural radiations, including cosmic, terrestrial, and food radiation. PMID:24223380

  17. Electromagnetic wave collapse in a radiation background.

    PubMed

    Marklund, Mattias; Brodin, Gert; Stenflo, Lennart

    2003-10-17

    The nonlinear interaction, due to quantum electrodynamical (QED) effects between an electromagnetic pulse and a radiation background, is investigated by combining the methods of radiation hydrodynamics with the QED theory for photon-photon scattering. For the case of a single coherent electromagnetic pulse, we obtain a Zakharov-like system, where the radiation pressure of the pulse acts as a driver of acoustic waves in the photon gas. For a sufficiently intense pulse and/or background energy density, there is focusing and the subsequent collapse of the pulse. The relevance of our results for various astrophysical applications are discussed.

  18. Background compensation for a radiation level monitor

    DOEpatents

    Keefe, D.J.

    1975-12-01

    Background compensation in a device such as a hand and foot monitor is provided by digital means using a scaler. With no radiation level test initiated, a scaler is down-counted from zero according to the background measured. With a radiation level test initiated, the scaler is up-counted from the previous down-count position according to the radiation emitted from the monitored object and an alarm is generated if, with the scaler having crossed zero in the positive going direction, a particular number is exceeded in a specific time period after initiation of the test. If the test is initiated while the scale is down-counting, the background count from the previous down- count stored in a memory is used as the initial starting point for the up-count.

  19. Interpretation of observed cosmic microwave background radiation

    NASA Technical Reports Server (NTRS)

    Alfven, H.; Mendis, A.

    1977-01-01

    It is argued that the 'surface of last scattering' of the observed microwave background radiation corresponds to the distribution of dust in galaxies or protogalaxies with a temperature of about 110 K at the epoch corresponding to Z roughly equal to 40. This is in contrast with the plasma temperature of over 3,000 K at an earlier epoch (Z greater than about 1,000), as given by the canonical model of big bang cosmologies. In view of this, the claim that the microwave background radiation lends strong support to hot big bang cosmologies is without foundation.

  20. Gamma radiation background measurements from Spacelab 2

    NASA Technical Reports Server (NTRS)

    Paciesas, William S.; Gregory, John C.; Fishman, Gerald J.

    1988-01-01

    A Nuclear Radiation Monitor incorporating a NaI(Tl) scintillation detector was flown as part of the verification flight instrumentation on the Spacelab 2 mission, July 29 to August 6, 1985. Gamma-ray spectra were measured with better than 20 s resolution throughout most of the mission in the energy range 0.1 to 30 MeV. Knowledge of the decay characteristics and the geomagnetic dependence of the counting rates enable measurement of the various components of the Spacelab gamma-ray background: prompt secondary radiation, Earth albedo, and delayed induced radioactivity. The status of the data analysis and present relevant examples of typical background behavior are covered.

  1. Gamma radiation background measurements from Spacelab 2

    NASA Technical Reports Server (NTRS)

    Paciesas, William S.; Gregory, John C.; Fishman, Gerald J.

    1989-01-01

    A Nuclear Radiation Monitor incorporating a NaI(Tl) scintillation detector was flown as part of the verification flight instrumentation on the Spacelab 2 mission, July 29 to August 6, 1985. Gamma-ray spectra were measured with better than 20 s resolution throughout most of the mission in the energy range 0.1 to 30 MeV. Knowledge of the decay characteristics and the geomagnetic dependence of the counting rates enable measurement of the various components of the Spacelab gamma-ray background: prompt secondary radiation, earth albedo, and delayed induced radioactivity. The status of the data analysis and present relevant examples of typical background behavior are covered.

  2. High-energy radiation background in space

    NASA Technical Reports Server (NTRS)

    Rester, A. C., Jr. (Editor); Trombka, J. I. (Editor)

    1989-01-01

    The radiation environment of near-earth space and its effects on biological and hardware systems are examined in reviews and reports. Sections are devoted to particle interactions and propagation, data bases, instrument background and dosimetry, detectors and experimental progress, biological effects, and future needs and strategies. Particular attention is given to angular distributions and spectra of geomagnetically trapped protons in LEO, bremsstrahlung production by electrons, nucleon-interaction data bases for background estimates, instrumental and atmospheric background lines observed by the SMM gamma-ray spectrometer, the GRAD high-altitude balloon flight over Antarctica, space protons and brain tumors, a new radioprotective antioxidative agent, LEO radiation measurements on the Space Station, and particle-background effects on the Hubble Space Telescope and the Lyman FUV Spectroscopic Explorer.

  3. Anisotropy of the cosmic microwave background radiation

    NASA Technical Reports Server (NTRS)

    Silk, J.

    1981-01-01

    Theoretical predictions of the angular anisotropy in the cosmic microwave background radiation on both small and large angular scales are presented, and the effect of massive neutrinos on both the background radiation anisotropy and on the galaxy correlation function over very large scales is reviewed. Current observations show that the quadrupole anisotropy provides the greatest constraint on theory, and the values for the gravitational potential fluctuations indicate that small amplitude but sufficiently large-scale density fluctuations, both at the present epoch and on the surface of last scattering, can produce significant large angular scale variations in the radiation temperature. Most importantly, it is proposed that the quadrupole moment is most simply and elegantly interpreted in terms of the density fluctuations on very large scales whose presence is inferred from the requirement that an initial fluctuation spectrum is required in order for structure to develop.

  4. The origin of the diffuse background gamma-radiation

    NASA Technical Reports Server (NTRS)

    Stecker, F. W.; Puget, J. L.

    1974-01-01

    Recent observations have now provided evidence for diffuse background gamma radiation extending to energies beyond 100 MeV. There is some evidence of isotropy and implied cosmological origin. Significant features in the spectrum of this background radiation have been observed which provide evidence for its origin in nuclear processes in the early stages of the big-band cosmology and tie in these processes with galaxy fromation theory. A crucial test of the theory may lie in future observations of the background radiation in the 100 MeV to 100 GeV energy range which may be made with large orbiting spark-chamber satellite detectors. A discussion of the theoretical interpretations of present data, their connection with baryon symmetric cosmology and galaxy formation theory, and the need for future observations are given.

  5. The origin of the diffuse background gamma radiation

    NASA Technical Reports Server (NTRS)

    Stecker, F. W.; Puget, J. L.

    1974-01-01

    Recent observations provided evidence for diffuse background gamma radiation extending to energies beyond 100 MeV, and evidence of isotropy and implied cosmological origin. Significant features in the spectrum of this background radiation were observed which provide evidence for its origin in nuclear processes in the early stages of big-bang cosmology, and connect these processes with the galaxy formation theory. A test of the theory is in future observations of the background radiation in the 100 MeK to 100 GeV energy range which are made with large orbiting spark-chamber satellite detectors. The theoretical interpretations of present data, their connection with baryon-symmetric cosmology and galaxy formation theory, and the need for future observations are discussed.

  6. Measurements of the cosmic background radiation

    NASA Technical Reports Server (NTRS)

    Lubin, P.; Villela, T.

    1986-01-01

    Data on the cosmic microwave background radiation obtained with a maser at 12 mm and a Schottky diode mixer at 3 mm are presented. The dipole anisotropy, apparently due to our motion, has been measured sufficiently well to determine our direction of motion within two degrees. The results show that the Galaxy is moving in a direction that is about 44 deg from the center of the Virgo cluster.

  7. Cosmic Infrared Background and Early Stellar Populations

    NASA Technical Reports Server (NTRS)

    Kashlinsky, A.

    2005-01-01

    Cosmic infrared background (CIB) contains information about galaxy luminosities over the entire history of the Universe and can be a powerful diagnostic of the early populations otherwise inaccessible to telescopic studies. Its measurements are very difficult because of the strong IR foregrounds from the Solar system and the Galaxy. Nevertheless, substantial recent progress in measuring the CIB and its structure has been made. The measurements now allow to set significant constraints on early galaxy evolution and, perhaps, even detect the elusive Population III era. We discuss briefly the theory behind the CIB, review the latest measurements of the CIB and its structure, and discuss their implications for detecting and/or constraining the first stars and their epochs.

  8. Polarization of the cosmic background radiation

    SciTech Connect

    Lubin, Philip M.; Smoot, George F.

    1980-08-01

    We discuss the technique and results of a measurement of the linear polarization of the Cosmic Background Radiation. Data taken between May 1978 and February 1980 from both the northern hemisphere (Berkeley Lat. 38{sup o}N) and the southern hemisphere (Lima Lat. 12{sup o}s) over 11 declinations from -37{sup o} to +63{sup o} show the radiation to be essentially unpolarized over all areas surveyed. Fitting all data gives the 95% confidence level limit on a linearly polarized component of 0.3 mK for spherical harmonics through third order. A fit of all data to the anisotropic axisymmetric model of Rees (1968) yields a 95% confidence level limit of 0.15 mK for the magnitude of the polarized component. Constraints on various cosmological models are discussed in light of these limits.

  9. Cosmic ultraviolet background radiation and zodiacal light

    NASA Technical Reports Server (NTRS)

    Tennyson, P. D.; Henry, R. C.; Feldman, P. D.; Hartig, G. F.

    1988-01-01

    Spectroscopic measurements of the diffuse cosmic UV background in the 1700-2850-A range are presented. In agreement with previous results, the data have resulted in the detection at high Galactic latitude of an intensity of 300 + or - 100 photons/sq cm s sr A at 1800 A without correction for starlight or airglow, a similar intensity over the 1900-2500-A range after correction for measured airglow, and a similar intensity over the 2500-2800-A range after correction for zodiacal light. It is suggested that this radiation may originate partly in line radiation from a Galactic halo and partly from extragalactic sources, perhaps the integrated light of distant galaxies.

  10. Polarization of the cosmic background radiation

    SciTech Connect

    Lubin, P.M.

    1980-03-01

    The results and technique of a measurement of the linear polarization of the Cosmic Background Radiation are discussed. The ground-based experiment utilizes a single horn (7/sup 0/ beam width) Dicke-type microwave polarimeter operating at 33 GHz (9.1 mm). Data taken between May 1978 and February 1980 from both the northern hemisphere (Berkeley Lat. = 38/sup 0/N) and the southern hemisphere (Lima Lat. = 12/sup 0/S) show the radiation to be essentially unpolarized over all areas surveyed. For the 38/sup 0/ declination data the 95% confidence level limit on a linearly polarized component is 0.3 mK for the average and 12 and 24 hour periods. Fitting all data gives the 95% confidence level limit on a linearly polarized component of 0.3 mK for spherical harmonics through third order. Constraints on various cosmological models are discussed in light of these limits.

  11. Measurements of the cosmic background radiation

    NASA Technical Reports Server (NTRS)

    Lubin, P.; Villela, T.

    1987-01-01

    Maps of the large scale structure (theta is greater than 6 deg) of the cosmic background radiation covering 90 percent of the sky are now available. The data show a very strong 50-100 sigma (statistical error) dipole component, interpreted as being due to our motion, with a direction of alpha = 11.5 + or - 0.15 hours, sigma = -5.6 + or - 2.0 deg. The inferred direction of the velocity of our galaxy relative to the cosmic background radiation is alpha = 10.6 + or - 0.3 hours, sigma = -2.3 + or - 5 deg. This is 44 deg from the center of the Virgo cluster. After removing the dipole component, the data show a galactic signature but no apparent residual structure. An autocorrelation of the residual data, after substraction of the galactic component from a combined Berkeley (3 mm) and Princeton (12 mm) data sets, show no apparent structure from 10 to 180 deg with a rms of 0.01 mK(sup 2). At 90 percent confidence level limit of .00007 is placed on a quadrupole component.

  12. The Cosmic Microwave Background Radiation and its Polarization

    NASA Astrophysics Data System (ADS)

    Wollack, Edward

    2016-03-01

    The cosmic microwave background (CMB) radiation and its faint polarization have provided a unique means to constrain the physical state of the early Universe. Continued advances in instrumentation, observation, and analysis have revealed polarized radiation signatures associated with gravitational lensing and have heightened the prospects for using precision polarimetry to experimentally confront the inflationary paradigm. Characterization of this relic radiation field has the power to constrain or reveal the detailed properties of astroparticle species and long wave gravitational radiation. On going and planned CMB polarization efforts from the ground, balloon, and space borne platforms will be briefly surveyed. Recent community activities by the Inflation Probe Science Interest Group (IPSIG) will also be summarized. NASA PCOS mini-symposium (invited IPSIG talk).

  13. Primordial helium and the cosmic background radiation

    SciTech Connect

    Steigman, Gary

    2010-04-01

    The products of primordial nucleosynthesis, along with the cosmic microwave background (CMB) photons, are relics from the early evolution of the Universe whose observations probe the standard model of cosmology and provide windows on new physics beyond the standard models of cosmology and of particle physics. According to the standard, hot big bang cosmology, long before any stars have formed a significant fraction ( ∼ 25%) of the baryonic mass in the Universe should be in the form of helium-4 nuclei. Since current observations of {sup 4}He are restricted to low redshift regions where stellar nucleosynthesis has occurred, an observation of high redshift, prestellar, truly primordial {sup 4}He would constitute a fundamental test of the hot, big bang cosmology. At recombination, long after big bang nucleosynthesis (BBN) has ended, the temperature anisotropy spectrum imprinted on the CMB depends on the {sup 4}He abundance through its connection to the electron density and the effect of the electron density on Silk damping. Since the relic abundance of {sup 4}He is relatively insensitive to the universal density of baryons, but is sensitive to a non-standard, early Universe expansion rate, the primordial mass fraction of {sup 4}He, Yp, offers a test of the consistency of the standard models of BBN and the CMB and, provides constraints on non-standard physics. Here, the WMAP seven year data (supplemented by other CMB experiments), which lead to an indirect determination of Yp at high redshift, are compared to the BBN predictions and to the independent, direct observations of {sup 4}He in low redshift, extragalactic HII regions. At present, given the very large uncertainties in the CMB-determined primordial {sup 4}He abundance (as well as for the helium abundances inferred from HII region observations), any differences between the BBN predictions and the CMB observations are small, at a level ∼<1.5σ.

  14. CERN-derived analysis of lunar radiation backgrounds

    NASA Technical Reports Server (NTRS)

    Wilson, Thomas L.; Svoboda, Robert

    1993-01-01

    The Moon produces radiation which background-limits scientific experiments there. Early analyses of these backgrounds have either failed to take into consideration the effect of charm in particle physics (because they pre-dated its discovery), or have used branching ratios which are no longer strictly valid (due to new accelerator data). We are presently investigating an analytical program for deriving muon and neutrino spectra generated by the Moon, converting an existing CERN computer program known as GEANT which does the same for the Earth. In so doing, this will (1) determine an accurate prompt neutrino spectrum produced by the lunar surface; (2) determine the lunar subsurface particle flux; (3) determine the consequence of charm production physics upon the lunar background radiation environment; and (4) provide an analytical tool for the NASA astrophysics community with which to begin an assessment of the Moon as a scientific laboratory versus its particle radiation environment. This will be done on a recurring basis with the latest experimental results of the particle data groups at Earth-based high-energy accelerators, in particular with the latest branching ratios for charmed meson decay. This will be accomplished for the first time as a full 3-dimensional simulation.

  15. Cosmic microwave background and first molecules in the early universe

    NASA Astrophysics Data System (ADS)

    Signore, Monique; Puy, Denis

    2009-01-01

    Besides the Hubble expansion of the universe, the main evidence in favor of the big-bang theory was the discovery, by Penzias and Wilson, of the cosmic microwave background (hereafter CMB) radiation. In 1990, the COBE satellite (Cosmic Background Explorer) revealed an accurate black-body behavior with a temperature around 2.7 K. Although the microwave background is very smooth, the COBE satellite did detect small variations—at the level of one part in 100 000—in the temperature of the CMB from place to place in the sky. These ripples are caused by acoustic oscillations in the primordial plasma. While COBE was only sensitive to long-wavelength waves, the Wilkinson Microwave Anisotropy Probe (WMAP)—with its much higher resolution—reveals that the CMB temperature variations follow the distinctive pattern predicted by cosmological theory. Moreover, the existence of the microwave background allows cosmologists to deduce the conditions present in the early stages of the big bang and, in particular, helps to account for the chemistry of the universe. This report summarizes the latest measurements and studies of the CMB with the new calculations about the formation of primordial molecules. The PLANCK mission—planned to be launched in 2009—is also presented.

  16. Social Background Differences in Early Family Behavior

    ERIC Educational Resources Information Center

    Schoen, Robert; Landale, Nancy S.; Daniels, Kimberly; Cheng, Yen-Hsin Alice

    2009-01-01

    Social background has historically been recognized as a major factor influencing family behavior, though recent work has largely emphasized racial/ethnic influences. Here we use 1994 - 1995 and 2001 - 2002 Add Health data to examine the cohabitation, first marriage, and first birth experience of young women. In a multi state life table context,…

  17. Spectral Analysis in High Radiation Space Backgrounds with Robust Fitting

    NASA Technical Reports Server (NTRS)

    Lasche, G. P.; Coldwell, R. L.; Nobel, L. A.; Rester, A. C.; Trombka, J. I.

    1997-01-01

    Spectral analysis software is tested for its ability to fit spectra from space. The approach, which emphasizes the background shape function, is uniquely suited to the identification of weak-strength nuclides in high-radiation background environments.

  18. Summary of the Workshop on Ultraviolet Cosmic Background Radiation

    NASA Technical Reports Server (NTRS)

    Henry, R. C.

    1981-01-01

    The relationship of the ultraviolet background radiation to the X-ray background is shown. The ultraviolet background, which is four orders of magnitude brighter than the x-ray background, is much less well determined. The relationship of the ultraviolet background to the EUV background and an excellent summary of the discordant ultraviolet observations at high galactic latitudes are given. A picture of the universe from the point of view of those who study ultraviolet background radiation, with emphasis on the various sources of noise that can affect the measurements is presented. The altitudes of various observing platforms are also indicated.

  19. Low Frequency Electromagnetic Background Radiation From Electron Acceleration Above Thunderclouds

    NASA Astrophysics Data System (ADS)

    Fullekrug, Martin; Mezentsev, Andrew; Soula, Serge; van der Velde, Oscar; Farges, Thomas

    2013-04-01

    It was recently proposed that the acceleration of electrons during the growth and branching of streamers above thunderclouds initiated by intense lightning discharges could result in detectable low frequency electromagnetic radiation from several tens of kHz up to several hundreds of kHz (Qin et al., GRL, 2012). The intensity of the predicted radiation scales with the streamer density which is particularly large during spectacular sprite occurrences such as jellyfish sprites and/or dancing sprites. Dancing sprites are up to one second long sequences of consecutive sprites or sprite groups which are typically separated by some hundreds of milliseconds and which tend to follow the spatial development of large scale intracloud lightning discharges. A particularly spectacular series of 10 dancing sprite events over a Mediterranean mesoscale convective system was recorded with a low light video camera in south-eastern France during the early morning hours of August 31, 2012. Each dancing sprite event was composed of ~3-4 consecutive sprites or groups of sprites. All of these sprite occurrences were associated with a sudden enhancement ~2 uV/m/Hz-1/2 of the low frequency electromagnetic background radiation as measured with a radio receiver in south-west England. It is estimated that ~1000 streamers at a height of ~40 km are necessary to epxlain the observed electric field strengths. These sudden enhancements are superimposed on a more continuous low frequency electromagnetic background radiation which accompanies each dancing sprite event. It is speculated that this low frequency 'radio glow' results from filamentary streamers near the cloud top as a result of the large scale electrostatic charging of the thundercloud and that it may be used as an indicator for sprite occurrences in future studies.

  20. Cosmic far-ultraviolet background radiation

    NASA Technical Reports Server (NTRS)

    Henry, R. C.

    1982-01-01

    It is demonstrated that interstellar dust grains forward-scatter far-ultraviolet radiation extremely strongly: the value of the Henyey-Greenstein scattering parameter g at 1425 A is shown to be at least 0.75; the actual value is very likely greater than 0.9. Also, observations of the Virgo cluster of galaxies sets a limit of tau greater than 2 x 10 to the 25th sec on the lifetime of 17-20 ev/C-squared heavy neutrinos, if such neutrinos are responsible for the gravitational binding of the cluster.

  1. Spectrum of the microwave background radiation

    NASA Technical Reports Server (NTRS)

    Richards, P. L.

    1982-01-01

    A review is given of the present status of measurements of the spectrum of the microwave background. Factors that limit experimental accuracy are discussed with particular reference to high-frequency measurements. A selection of the available measurements yields a data set that is reasonably consistent with the black-body spectrum for a temperature of 2.9 K. A simple statistical analysis suggests either that there are errors in the data set, or that deviations from a black-body spectrum exist. The difficulties inherent in properly averaging the results from different observers are described. Prospects for improved measurements are summarized.

  2. Spectrum of the microwave background radiation

    SciTech Connect

    Richards, P.L.

    1982-04-01

    A review is given of the present status of measurements of the spectrum of the microwave background. Factors which limit experimental accuracy are discussed with particular reference to high frequency measurements. A selection of the available measurements yields a data set which is reasonably consistent with the blackbody spectrum for a temperature of 2.9 K. A simple statistical analysis suggests either that there are errors in the data set, or that deviations from a blackbody spectrum exist. The difficulties inherent in property averaging the results from different observers are described. Prospects for improved measurements will be summarized.

  3. Cancer Mortality Among People Living in Areas With Various Levels of Natural Background Radiation

    PubMed Central

    Fornalski, Krzysztof W.; Feinendegen, Ludwig E.

    2015-01-01

    There are many places on the earth, where natural background radiation exposures are elevated significantly above about 2.5 mSv/year. The studies of health effects on populations living in such places are crucially important for understanding the impact of low doses of ionizing radiation. This article critically reviews some recent representative literature that addresses the likelihood of radiation-induced cancer and early childhood death in regions with high natural background radiation. The comparative and Bayesian analysis of the published data shows that the linear no-threshold hypothesis does not likely explain the results of these recent studies, whereas they favor the model of threshold or hormesis. Neither cancers nor early childhood deaths positively correlate with dose rates in regions with elevated natural background radiation. PMID:26674931

  4. Cosmic background radiation anisotropy in an open inflation, cold dark matter cosmogony

    NASA Technical Reports Server (NTRS)

    Kamionkowski, Marc; Ratra, Bharat; Spergel, David N.; Sugiyama, Naoshi

    1994-01-01

    We compute the cosmic background radiation anisotropy, produced by energy-density fluctuations generated during an early epoch of inflation, in an open cosmological model based on the cold dark matter scenario. At Omega(sub 0) is approximately 0.3-0.4, the Cosmic Background Explorer (COBE) normalized open model appears to be consistent with most observations.

  5. Is natural background or radiation from nuclear power plants leukemogenic

    SciTech Connect

    Cronkite, E.P.

    1989-01-01

    The objective in this review is to provide some facts about normal hemopoietic cell proliferation relevant to leukemogenesis, physical, chemical, and biological facts about radiation effects with the hope that each person will be able to decide for themselves whether background radiation or emissions from nuclear power plants and facilities significantly add to the spontaneous leukemia incidence. 23 refs., 1 tab.

  6. Balloon measurements of the far-infrared background radiation.

    NASA Technical Reports Server (NTRS)

    Muehlner, D.; Weiss, R.

    1973-01-01

    Description of a balloon-borne radiometer designed to make direct measurements of the background radiation in the spectral range from 1 to 20 cm, and evaluation of the results of two balloon flights performed with the aid of this radiometer. Measurements in five different passbands in the spectral region below 20 per cm were made with a liquid-helium-cooled radiometer in two flights at approximately 40-km altitude. The results obtained are found to be consistent with a 2.7 K thermal radiation background. In addition, an atmospheric radiation of certain magnitude is found to dominate the region above 11 per cm.

  7. Measurements of background gamma radiation on Spacelab 2

    NASA Technical Reports Server (NTRS)

    Fishman, G. J.; Paciesas, W. S.; Gregory, J. C.

    1987-01-01

    A nuclear radiation monitor (NRM) which was flown as part of the verification instrumentation on the Spacelab 2 mission (July 29 - August 6, 1985) recorded spectra every 20 seconds and counting rates in coarse energy bands on finer time scales. The gamma radiation environment on Spacelab is characterized by cosmic-ray and trapped proton secondary radiation in the Spacelab/Shuttle, earth albedo radiation, and delayed induced radioactivity in the detector and surrounding materials. It is found that passages through South Atlantic Anomaly protons produce a well-defined background enhancement.

  8. Cosmic Background Radiation and “ether-drift” experiments

    NASA Astrophysics Data System (ADS)

    Consoli, M.; Pluchino, A.; Rapisarda, A.

    2016-01-01

    “Ether-drift” experiments have played a crucial role for the origin of relativity. Though, a recent re-analysis shows that those original measurements where light was still propagating in gaseous systems, differently from the modern experiments in vacuum and in solid dielectrics, indicate a small universal anisotropy which is naturally interpreted in terms of a non-local thermal gradient. We argue that this could possibly be the effect, on weakly bound gaseous matter, of the temperature gradient due to the Earth's motion within the Cosmic Background Radiation (CBR). Therefore, a check with modern laser interferometers is needed to reproduce the conditions of those early measurements with today's much greater accuracy. We emphasize that an unambiguous confirmation of our interpretation would have far-reaching consequences. For instance, it would imply that all physical systems on the moving Earth are exposed to a tiny energy flow, an effect which, in principle, could also induce forms of self-organization in matter.

  9. Measurement of natural background radiation intensity on a train.

    PubMed

    Chen, Yen-Fu; Lin, Jeng-Wei; Sheu, Rong-Jiun; Lin, Uei-Tyng; Jiang, Shiang-Huei

    2011-03-01

    This work aims to measure different components of natural background radiation on a train. A radiation measurement system consisting of four types of radiation detectors, namely, a Berkeley Lab cosmic-ray detector, moderated (3)He detector, high-pressure ionisation chamber and NaI(Tl) spectrometer, associated with a global positioning system unit was established for this purpose. For the commissioning of the system, a test measurement on a train along the railway around the northern Taiwan coast from Hsinchu to Hualien with a distance of ∼ 275 km was carried out. No significant variation of the intensities of the different components of natural background radiation was observed, except when the train went underground or in the tunnels. The average external dose rate received by the crew of the train was estimated to be 62 nSv h(-1).

  10. Ultraviolet background radiation and the search for decaying neutrinos

    NASA Technical Reports Server (NTRS)

    Henry, R. C.

    1981-01-01

    The spectrum of the observed far-ultraviolet background at high galactic latitudes is studied in order to find evidence of radiation from neutrino decay. It is concluded that at latitudes above about 20 degrees, the limit on any light scattered from interstellar dust or the limit on light from any source other than stars is of order 300 photons/sq cm sec ster A. Superficial evidence for radiation from decaying neutrinos is provided by an examination of the spectrum of the observed background at the highest galactic latitudes, although the spectrum is so uncertain that conclusions are not possible.

  11. Cosmic Radiation Fields: Sources in the early Universe

    NASA Astrophysics Data System (ADS)

    Raue, Martin; Kneiske, Tanja; Horns, Dieter; Elsaesser, Dominik; Hauschildt, Peter

    The workshop "Cosmic Radiation Fields - Sources in the Early Universe" (CRF 2010) focuses on the connection between the extragalactic infrared background and sources in the early universe, in particular stars powered by dark matter burning (Dark Stars; DS). The workshop covers the following topics: the cosmic infrared background, formation of early stars, dark stars, effect of dark matter in the early universe, dark matter halos, primordial star formation rate, and reionization. Further information can be found on the conference webpage: http://www.desy.de/crf2010/. Organizing committee: Tanja Kneiske, Martin Raue, Dominik Elsaesser, Alexander Gewering-Peine, Peter Hausschildt, Dieter Horns, and Andreas Maurer.

  12. Background radiation measurements at high power research reactors

    SciTech Connect

    Ashenfelter, J.; Balantekin, B.; Baldenegro, C. X.; Band, H. R.; Barclay, G.; Bass, C. D.; Berish, D.; Bowden, N. S.; Bryan, C. D.; Cherwinka, J. J.; Chu, R.; Classen, T.; Davee, D.; Dean, D.; Deichert, G.; Dolinski, M. J.; Dolph, J.; Dwyer, D. A.; Fan, S.; Gaison, J. K.; Galindo-Uribarri, A.; Gilje, K.; Glenn, A.; Green, M.; Han, K.; Hans, S.; Heeger, K. M.; Heffroni, B.; Jaffe, D. E.; Kettell, S.; Langford, T. J.; Littlejohn, B. R.; Martinez, D.; McKeown, R. D.; Morrell, S.; Mueller, P. E.; Mumm, H. P.; Napolitano, J.; Norcini, D.; Pushin, D.; Romero, E.; Rosero, R.; Saldana, L.; Seilhan, B. S.; Sharma, R.; Stemen, N. T.; Surukuchi, P. T.; Thompson, S. J.; Varner, R. L.; Wang, W.; Watson, S. M.; White, B.; White, C.; Wilhelmi, J.; Williams, C.; Wise, T.; Yao, H.; Yeh, M.; Yen, Y. -R.; Zhang, C.; Zhang, X.

    2015-10-23

    Research reactors host a wide range of activities that make use of the intense neutron fluxes generated at these facilities. Recent interest in performing measurements with relatively low event rates, e.g. reactor antineutrino detection, at these facilities necessitates a detailed understanding of background radiation fields. Both reactor-correlated and naturally occurring background sources are potentially important, even at levels well below those of importance for typical activities. Here we describe a comprehensive series of background assessments at three high-power research reactors, including -ray, neutron, and muon measurements. For each facility we describe the characteristics and identify the sources of the background fields encountered. Furthermore, the general understanding gained of background production mechanisms and their relationship to facility features will prove valuable for the planning of any sensitive measurement conducted therein.

  13. Background radiation measurements at high power research reactors

    SciTech Connect

    Ashenfelter, J.; Yeh, M.; Balantekin, B.; Baldenegro, C. X.; Band, H. R.; Barclay, G.; Bass, C. D.; Berish, D.; Bowden, N. S.; Bryan, C. D.; Cherwinka, J. J.; Chu, R.; Classen, T.; Davee, D.; Dean, D.; Deichert, G.; Dolinski, M. J.; Dolph, J.; Dwyer, D. A.; Fan, S.; Gaison, J. K.; Galindo-Uribarri, A.; Gilje, K.; Glenn, A.; Green, M.; Han, K.; Hans, S.; Heeger, K. M.; Heffron, B.; Jaffe, D. E.; Kettell, S.; Langford, T. J.; Littlejohn, B. R.; Martinez, D.; McKeown, R. D.; Morrell, S.; Mueller, P. E.; Mumm, H. P.; Napolitano, J.; Norcini, D.; Pushin, D.; Romero, E.; Rosero, R.; Saldana, L.; Seilhan, B. S.; Sharma, R.; Stemen, N. T.; Surukuchi, P. T.; Thompson, S. J.; Varner, R. L.; Wang, W.; Watson, S. M.; White, B.; White, C.; Wilhelmi, J.; Williams, C.; Wise, T.; Yao, H.; Yen, Y. -R.; Zhang, C.; Zhang, X.

    2015-10-23

    Research reactors host a wide range of activities that make use of the intense neutron fluxes generated at these facilities. Recent interest in performing measurements with relatively low event rates, e.g. reactor antineutrino detection, at these facilities necessitates a detailed understanding of background radiation fields. Both reactor-correlated and naturally occurring background sources are potentially important, even at levels well below those of importance for typical activities. Here we describe a comprehensive series of background assessments at three high-power research reactors, including γ-ray, neutron, and muon measurements. For each facility we describe the characteristics and identify the sources of the background fields encountered. Furthermore, the general understanding gained of background production mechanisms and their relationship to facility features will prove valuable for the planning of any sensitive measurement conducted therein.

  14. Search for the Cosmic Infrared Background Radiation using COBE Data

    NASA Technical Reports Server (NTRS)

    Hauser, Michael

    2001-01-01

    This project was initiated to allow completion of the primary investigation of the Diffuse Infrared Background Experiment (DIRBE) on NASA's Cosmic Background Explorer (CORE) mission, and to study the implications of those findings. The Principal Investigator (PI) on this grant was also the Principal Investigator on the DIRBE team. The project had two specific goals: Goal 1: Seek improved limits upon, or detections of, the cosmic infrared background radiation using data from the COBE Diffuse Infrared Background Experiment (DIRBE). Goal 2: Explore the implications of the limits and measured values of the cosmic infrared background for energy releases in the Universe since the formation of the first luminous sources. Both of these goals have been successfully accomplished.

  15. Position sensitive detection of neutrons in high radiation background field

    SciTech Connect

    Vavrik, D.; Jakubek, J.; Pospisil, S.; Vacik, J.

    2014-01-15

    We present the development of a high-resolution position sensitive device for detection of slow neutrons in the environment of extremely high γ and e{sup −} radiation background. We make use of a planar silicon pixelated (pixel size: 55 × 55 μm{sup 2}) spectroscopic Timepix detector adapted for neutron detection utilizing very thin {sup 10}B converter placed onto detector surface. We demonstrate that electromagnetic radiation background can be discriminated from the neutron signal utilizing the fact that each particle type produces characteristic ionization tracks in the pixelated detector. Particular tracks can be distinguished by their 2D shape (in the detector plane) and spectroscopic response using single event analysis. A Cd sheet served as thermal neutron stopper as well as intensive source of gamma rays and energetic electrons. Highly efficient discrimination was successful even at very low neutron to electromagnetic background ratio about 10{sup −4}.

  16. THE MYSTERY OF THE COSMIC DIFFUSE ULTRAVIOLET BACKGROUND RADIATION

    SciTech Connect

    Henry, Richard Conn; Murthy, Jayant; Overduin, James; Tyler, Joshua E-mail: jmurthy@yahoo.com E-mail: 97tyler@cardinalmail.cua.edu

    2015-01-01

    The diffuse cosmic background radiation in the Galaxy Evolution Explorer far-ultraviolet (FUV, 1300-1700 Å) is deduced to originate only partially in the dust-scattered radiation of FUV-emitting stars: the source of a substantial fraction of the FUV background radiation remains a mystery. The radiation is remarkably uniform at both far northern and far southern Galactic latitudes and increases toward lower Galactic latitudes at all Galactic longitudes. We examine speculation that this might be due to interaction of the dark matter with the nuclei of the interstellar medium, but we are unable to point to a plausible mechanism for an effective interaction. We also explore the possibility that we are seeing radiation from bright FUV-emitting stars scattering from a ''second population'' of interstellar grains—grains that are small compared with FUV wavelengths. Such grains are known to exist, and they scatter with very high albedo, with an isotropic scattering pattern. However, comparison with the observed distribution (deduced from their 100 μm emission) of grains at high Galactic latitudes shows no correlation between the grains' location and the observed FUV emission. Our modeling of the FUV scattering by small grains also shows that there must be remarkably few such ''smaller'' grains at high Galactic latitudes, both north and south; this likely means simply that there is very little interstellar dust of any kind at the Galactic poles, in agreement with Perry and Johnston. We also review our limited knowledge of the cosmic diffuse background at ultraviolet wavelengths shortward of Lyα—it could be that our ''second component'' of the diffuse FUV background persists shortward of the Lyman limit and is the cause of the reionization of the universe.

  17. Cosmic microwave background radiation anisotropies in brane worlds.

    PubMed

    Koyama, Kazuya

    2003-11-28

    We propose a new formulation to calculate the cosmic microwave background (CMB) spectrum in the Randall-Sundrum two-brane model based on recent progress in solving the bulk geometry using a low energy approximation. The evolution of the anisotropic stress imprinted on the brane by the 5D Weyl tensor is calculated. An impact of the dark radiation perturbation on the CMB spectrum is investigated in a simple model assuming an initially scale-invariant adiabatic perturbation. The dark radiation perturbation induces isocurvature perturbations, but the resultant spectrum can be quite different from the prediction of simple mixtures of adiabatic and isocurvature perturbations due to Weyl anisotropic stress.

  18. Long-range correlation in cosmic microwave background radiation.

    PubMed

    Movahed, M Sadegh; Ghasemi, F; Rahvar, Sohrab; Tabar, M Reza Rahimi

    2011-08-01

    We investigate the statistical anisotropy and gaussianity of temperature fluctuations of Cosmic Microwave Background (CMB) radiation data from the Wilkinson Microwave Anisotropy Probe survey, using the Multifractal Detrended Fluctuation Analysis, Rescaled Range, and Scaled Windowed Variance methods. Multifractal Detrended Fluctuation Analysis shows that CMB fluctuations has a long-range correlation function with a multifractal behavior. By comparing the shuffled and surrogate series of CMB data, we conclude that the multifractality nature of the temperature fluctuation of CMB radiation is mainly due to the long-range correlations, and the map is consistent with a gaussian distribution.

  19. Background radiation measurements at high power research reactors

    DOE PAGESBeta

    Ashenfelter, J.; Balantekin, B.; Baldenegro, C. X.; Band, H. R.; Barclay, G.; Bass, C. D.; Berish, D.; Bowden, N. S.; Bryan, C. D.; Cherwinka, J. J.; et al

    2015-10-23

    Research reactors host a wide range of activities that make use of the intense neutron fluxes generated at these facilities. Recent interest in performing measurements with relatively low event rates, e.g. reactor antineutrino detection, at these facilities necessitates a detailed understanding of background radiation fields. Both reactor-correlated and naturally occurring background sources are potentially important, even at levels well below those of importance for typical activities. Here we describe a comprehensive series of background assessments at three high-power research reactors, including -ray, neutron, and muon measurements. For each facility we describe the characteristics and identify the sources of the backgroundmore » fields encountered. Furthermore, the general understanding gained of background production mechanisms and their relationship to facility features will prove valuable for the planning of any sensitive measurement conducted therein.« less

  20. Background radiation measurements at high power research reactors

    DOE PAGESBeta

    Ashenfelter, J.; Yeh, M.; Balantekin, B.; Baldenegro, C. X.; Band, H. R.; Barclay, G.; Bass, C. D.; Berish, D.; Bowden, N. S.; Bryan, C. D.; et al

    2015-10-23

    Research reactors host a wide range of activities that make use of the intense neutron fluxes generated at these facilities. Recent interest in performing measurements with relatively low event rates, e.g. reactor antineutrino detection, at these facilities necessitates a detailed understanding of background radiation fields. Both reactor-correlated and naturally occurring background sources are potentially important, even at levels well below those of importance for typical activities. Here we describe a comprehensive series of background assessments at three high-power research reactors, including γ-ray, neutron, and muon measurements. For each facility we describe the characteristics and identify the sources of the backgroundmore » fields encountered. Furthermore, the general understanding gained of background production mechanisms and their relationship to facility features will prove valuable for the planning of any sensitive measurement conducted therein.« less

  1. Measurement of background gamma radiation in the northern Marshall Islands

    PubMed Central

    Bordner, Autumn S.; Crosswell, Danielle A.; Katz, Ainsley O.; Shah, Jill T.; Zhang, Catherine R.; Nikolic-Hughes, Ivana; Hughes, Emlyn W.; Ruderman, Malvin A.

    2016-01-01

    We report measurements of background gamma radiation levels on six islands in the northern Marshall Islands (Enewetak, Medren, and Runit onEnewetak Atoll; Bikini and Nam on Bikini Atoll; and Rongelap on Rongelap Atoll). Measurable excess radiation could be expected from the decay of 137Cs produced by the US nuclear testing program there from 1946 to 1958. These recordings are of relevance to safety of human habitation and resettlement. We find low levels of gamma radiation for the settled island of Enewetak [mean = 7.6 millirem/year (mrem/y) = 0.076 millisievert/year (mSv/y)], larger levels of gamma radiation for the island of Rongelap (mean = 19.8 mrem/y = 0.198 mSv/y), and relatively high gamma radiation on the island of Bikini (mean = 184 mrem/y = 1.84 mSv/y). Distributions of gamma radiation levels are provided, and hot spots are discussed. We provide interpolated maps for four islands (Enewetak, Medren, Bikini, and Rongelap), and make comparisons to control measurements performed on the island of Majuro in the southern Marshall Islands, measurements made in Central Park in New York City, and the standard agreed upon by the United States and the Republic of the Marshall Islands (RMI) governments (100 mrem/y = 1 mSv/y). External gamma radiation levels on Bikini Island significantly exceed this standard (P = <<0.01), and external gamma radiation levels on the other islands are below the standard. To determine conclusively whether these islands are safe for habitation, radiation exposure through additional pathways such as food ingestion must be considered. PMID:27274073

  2. Measurement of background gamma radiation in the northern Marshall Islands.

    PubMed

    Bordner, Autumn S; Crosswell, Danielle A; Katz, Ainsley O; Shah, Jill T; Zhang, Catherine R; Nikolic-Hughes, Ivana; Hughes, Emlyn W; Ruderman, Malvin A

    2016-06-21

    We report measurements of background gamma radiation levels on six islands in the northern Marshall Islands (Enewetak, Medren, and Runit onEnewetak Atoll; Bikini and Nam on Bikini Atoll; and Rongelap on Rongelap Atoll). Measurable excess radiation could be expected from the decay of (137)Cs produced by the US nuclear testing program there from 1946 to 1958. These recordings are of relevance to safety of human habitation and resettlement. We find low levels of gamma radiation for the settled island of Enewetak [mean = 7.6 millirem/year (mrem/y) = 0.076 millisievert/year (mSv/y)], larger levels of gamma radiation for the island of Rongelap (mean = 19.8 mrem/y = 0.198 mSv/y), and relatively high gamma radiation on the island of Bikini (mean = 184 mrem/y = 1.84 mSv/y). Distributions of gamma radiation levels are provided, and hot spots are discussed. We provide interpolated maps for four islands (Enewetak, Medren, Bikini, and Rongelap), and make comparisons to control measurements performed on the island of Majuro in the southern Marshall Islands, measurements made in Central Park in New York City, and the standard agreed upon by the United States and the Republic of the Marshall Islands (RMI) governments (100 mrem/y = 1 mSv/y). External gamma radiation levels on Bikini Island significantly exceed this standard (P = <0.01), and external gamma radiation levels on the other islands are below the standard. To determine conclusively whether these islands are safe for habitation, radiation exposure through additional pathways such as food ingestion must be considered.

  3. Measurement of background gamma radiation in the northern Marshall Islands.

    PubMed

    Bordner, Autumn S; Crosswell, Danielle A; Katz, Ainsley O; Shah, Jill T; Zhang, Catherine R; Nikolic-Hughes, Ivana; Hughes, Emlyn W; Ruderman, Malvin A

    2016-06-21

    We report measurements of background gamma radiation levels on six islands in the northern Marshall Islands (Enewetak, Medren, and Runit onEnewetak Atoll; Bikini and Nam on Bikini Atoll; and Rongelap on Rongelap Atoll). Measurable excess radiation could be expected from the decay of (137)Cs produced by the US nuclear testing program there from 1946 to 1958. These recordings are of relevance to safety of human habitation and resettlement. We find low levels of gamma radiation for the settled island of Enewetak [mean = 7.6 millirem/year (mrem/y) = 0.076 millisievert/year (mSv/y)], larger levels of gamma radiation for the island of Rongelap (mean = 19.8 mrem/y = 0.198 mSv/y), and relatively high gamma radiation on the island of Bikini (mean = 184 mrem/y = 1.84 mSv/y). Distributions of gamma radiation levels are provided, and hot spots are discussed. We provide interpolated maps for four islands (Enewetak, Medren, Bikini, and Rongelap), and make comparisons to control measurements performed on the island of Majuro in the southern Marshall Islands, measurements made in Central Park in New York City, and the standard agreed upon by the United States and the Republic of the Marshall Islands (RMI) governments (100 mrem/y = 1 mSv/y). External gamma radiation levels on Bikini Island significantly exceed this standard (P = <0.01), and external gamma radiation levels on the other islands are below the standard. To determine conclusively whether these islands are safe for habitation, radiation exposure through additional pathways such as food ingestion must be considered. PMID:27274073

  4. Impact of interacting dark sector on Cosmic Microwave Background Radiation

    NASA Astrophysics Data System (ADS)

    Verma, M. M.

    2014-03-01

    It has been shown earlier that an arc-like pattern found on the Cosmic Microwave Background Radiation (CMBR) may result from the decay of dark matter particles initiating near particle horizon in the Q-phase of the interacting cosmological constant (ICC) model. In the present work, an investigation is made into how the corresponding decay of such dark matter particles might influence these signatures, in view of the recent data on CMBR and the diffuse glow of the anomalous microwave radiation. We also discuss the constraints on such decay imposed by the interaction of the cosmological constant with the background. These predictions made in the ICC model can be verified in the concordance space of multiple observations.

  5. Study of Natural Background Radiation around Gurvanbulag Uranium Deposit Area

    NASA Astrophysics Data System (ADS)

    Enkhbat, N.; Norov, N.; Bat-Erdene, B.; Khuukhenkhuu, G.; Otgooloi, B.

    2009-03-01

    In this work, we will show the study of natural background radiation level around the Gurvanbulag (GB) uranium deposit area in the eastern part of Mongolia. We collected environmental soil samples from 102 points around GB Uranium deposit. Collected samples were measured by HPGe gamma spectrometer at Nuclear Research Center, National University of Mongolia. The averaged activity concentrations of Ra-226, Th-232, K-40, and Cs-137 were 37.1, 29, 939, and 17.7 Bq/kg, respectively.

  6. High Precision Cosmology with the Cosmic Background Radiation

    NASA Astrophysics Data System (ADS)

    Farhang, Marzieh

    In this thesis we investigate the two cosmic epochs of inflation and recombination, through their imprints on the temperature and polarization anisotropies of the cosmic microwave background radiation. To probe the early universe we develop a map-based maximum-likelihood estimator to measure the amplitude of inflation-induced gravity waves, parametrized by r, from the cosmic microwave background (CMB) polarization maps. Being optimal by construction, the estimator avoids E-B mixing, a possible source of contamination in the tiny B-mode detection, the target of many current and near future CMB experiments. We explore the leakage from the E- to the B-mode of polarization by using this estimator to study the linear response of the B-mode signal at different scales to variations in the E- mode power. Similarly, for various observational cases, we probe the dependence of r measurement on the signal from different scales of E and B polarization. The estimator is used to make forecasts for Spider-like and Planck-like experimental specifications and to investigate the sky-coverage optimization of the Spider-like case. We compare the forecast errors on r to the results from a similar multipole-based estimator which, by ignoring the mode-mixing, sets a lower limit on the achievable error on r. We find that an experiment with Spider-like specifications with fsky ˜ 0:02--0:2 could place a 2sigma r ≈ 0:014 bound (˜ 95% CL), which rises to 0:02 with an ℓ-dependent foreground residual left over from an assumed efficient component separation. For the Planck-like survey, a Galaxy-masked ( fsky = 0:75) sky would give 2sigmar ≈ 0:015, rising to ≈ 0:05 with the foreground residuals. We also use a novel information-based framework to compare how different generations of CMB experiments reveal information about the early universe, through their measurements of r. We also probe the epoch of recombination by investigating possible fluctuations in the free electron fraction Xe

  7. Assessment of Radiation Background Variation for Moving Detection Systems

    SciTech Connect

    Miller, James Christopher; Rennie, John Alan; Toevs, James Waldo; Wallace, Darrin J.; Abhold, Mark Edward

    2015-07-13

    The introduction points out that radiation backgrounds fluctuate across very short distances: factors include geology, soil composition, altitude, building structures, topography, and other manmade structures; and asphalt and concrete can vary significantly over short distances. Brief descriptions are given of the detection system, experimental setup, and background variation measurements. It is concluded that positive and negative gradients can greatly reduce the detection sensitivity of an MDS: negative gradients create opportunities for false negatives (nondetection), and positive gradients create a potentially unacceptable FAR (above 1%); the location of use for mobile detection is important to understand; spectroscopic systems provide more information for screening out false alarms and may be preferred for mobile use; and mobile monitor testing at LANL accounts for expected variations in the background.

  8. Radiometer system to map the cosmic background radiation.

    PubMed

    Gorenstein, M V; Muller, R A; Smoot, G F; Tyson, J A

    1978-04-01

    We have developed a 33-GHz airborne radiometer system to map large angular scale variations in the temperature of the 3 K cosmic background radiation. A ferrite circulator switches a room-temperature mixer between two antennas pointing 60 degrees apart in the sky. In 40 min of observing, the radiometer can measure the anisotropy of the microwave background with an accuracy of +/-1 mK rms, or about 1 part in 3000 of 3 K. The apparatus is flown in a U-2 jet to 20 km altitude where 33-GHz thermal microwave emission from the atmosphere is at a low level. A second radiometer, tuned to 54 GHz near oxygen emission lines, monitors spurious signals from residual atmospheric radiation. The antennas, which have an extremely low side-lobe response of less than -65 dB past 60 degrees , reject anisotropic radiation from the earth's surface. Periodic interchange of the antenna positions and reversal of the aircraft's flight direction cancel equipment-based imbalances. The system has been operated successfully in U-2 aircraft flown from NASA-Ames at Moffett Field, CA.

  9. Radiometer system to map the cosmic background radiation

    NASA Technical Reports Server (NTRS)

    Gorenstein, M. V.; Muller, R. A.; Smoot, G. F.; Tyson, J. A.

    1978-01-01

    A 33-GHz airborne radiometer system has been developed to map large angular scale variations in the temperature of the 3 K cosmic background radiation. A ferrite circulator switches a room-temperature mixer between two antennas pointing 60 deg apart in the sky. In 40 min of observing, the radiometer can measure the anisotropy of the microwave background with an accuracy of plus or minus 1 mK rms, or about 1 part in 3000 of 3 K. The apparatus is flown in a U-2 jet to 20 km altitude where 33-GHz thermal microwave emission from the atmosphere is at a low level. A second radiometer, tuned to 54 GHz near oxygen emission lines, monitors spurious signals from residual atmospheric radiation. The antennas, which have an extremely low side-lobe response of less than -65 dB past 60 deg, reject anisotropic radiation from the earth's surface. Periodic interchange of the antenna positions and reversal of the aircraft's flight direction cancel equipment-based imbalances. The system has been operated successfully in U-2 aircraft flown from NASA-Ames at Moffett Field, Calif.

  10. GEANT4 simulation of APEX background radiation and shielding

    NASA Astrophysics Data System (ADS)

    Kaluarachchi, Maduka M.; Cates, Gordon D.; Wojtsekhowski, B.

    2015-04-01

    The A' Experiment (APEX), which is approved to run at the Thomas Jefferson National Accelerator Facility (JLab) Hall A, will search for a new vector boson that is hypothesized to be a possible force carrier that couples to dark matter. APEX results should be sensitive to the mass range of 65 MeV to 550 MeV, and high sensitivity will be achieved by means of a high intensity 100 μA beam on a 0.5 g/cm2 Tungsten target resulting in very high luminosity. The experiment should be able to observe the A ' with a coupling constant α ' ~ 1 × 107 times smaller than the electromagnetic coupling constant α. To deal safely with such enormous intensity and luminosity, a full radiation analysis must be used to help with the design of proper radiation shielding. The purpose of this talk is to present preliminary results obtained by simulating radiation background from the APEX experiment using the 3D Monte-Carlo transport code Geant4. Included in the simulation is a detailed Hall A setup: the hall, spectrometers and shield house, beam dump, beam line, septa magnet with its field, as well as the production target. The results were compared to the APEX test run data and used in development of the radiation shielding for sensitive electronics.

  11. Human response to high-background radiation environments on Earth and in space

    NASA Astrophysics Data System (ADS)

    Durante, M.; Manti, L.

    The main long-term goal of the space exploration program is the colonization of the planets of the Solar System The high cosmic radiation equivalent dose rate represents a major problem for a stable and safe colonization of the planets The dose rate on Mars ranges between 60 and 150 mSv year depending on the Solar cycle and altitude and can reach values as high as 360 mSv year on the Moon The average dose rate on the Earth is about 3 mSv year reduced to about 1 mSv year excluding the internal exposure to Rn daughters However some areas of the Earth have anomalously high levels of background radiation Values 200-400 times higher than the world average are found in regions where monazite sand deposits are abundant Population in Tibet experience a high cosmic radiation background Epidemiological studies did not detect any adverse health effects in the populations living in those high-background radiation areas on Earth Chromosomal aberrations in the peripheral blood lymphocytes from the population living in the high-background radiation areas have been measured in several studies because the chromosomal damage represents an early biomarker of cancer risk Similar cytogenetic studies have been recently performed in cohort of astronauts involved in single or repeated space flights over many years A comparison of the cytogenetic findings in populations exposed at high dose rate on Earth or in space will be described

  12. Large-angular-scale anisotropy in the cosmic background radiation

    NASA Technical Reports Server (NTRS)

    Gorenstein, M. V.; Smoot, G. F.

    1981-01-01

    Results of an extended series of airborne measurements of large-angular-scale anisotropy in the 3-K cosmic background radiation are reported. A dual-antenna microwave radiometer operating at 33 GHz flown aboard a U-2 aircraft to 20-km altitude on 11 flights between December 1976 and May 1978 measured differential intensity between pairs of directions distributed over most of the Northern Hemisphere. Measurements show clear evidence of anisotropy that is readily interpreted as due to the solar motion relative to the sources of the radiation. The anisotropy is well fitted by a first order spherical harmonic of amplitude 3.6 + or - 0.5 mK, corresponding to a velocity of 360 + or - 50 km/s toward the direction 11.2 + or - 0.5 hours of right ascension and 19 deg + or - 8 deg declination.

  13. New Measurements of the Cosmic Background Radiation Spectrum

    SciTech Connect

    Smoot, G.F.; De Amici, G.; Levin, S.; Witebsky, C.

    1984-12-01

    We have continued our program to measure the long-wavelength spectrum of the cosmic background radiation. Our previous observations were at five wavelengths--0.33, 0.9, 3.0, 6.3, and 12.0 cm--and had a weighted average value of 2.73 {+-} 0.05 K and deviated from a Planckian spectrum by less than 6%. In August 1984, we repeated our observations at 3.0, 0.9, and 0.33 cm and made new observations with a radiometer tunable from 1.7 to 15 cm. Preliminary analysis indicate that the new data are consistent with our previous results.

  14. Search for Linear Polarization of the Cosmic Background Radiation

    DOE R&D Accomplishments Database

    Lubin, P. M.; Smoot, G. F.

    1978-10-01

    We present preliminary measurements of the linear polarization of the cosmic microwave background (3 deg K blackbody) radiation. These ground-based measurements are made at 9 mm wavelength. We find no evidence for linear polarization, and set an upper limit for a polarized component of 0.8 m deg K with a 95% confidence level. This implies that the present rate of expansion of the Universe is isotropic to one part in 10{sup 6}, assuming no re-ionization of the primordial plasma after recombination

  15. The submillimeter spectrum of the cosmic background radiation

    NASA Technical Reports Server (NTRS)

    Matsumoto, T.; Hayakawa, S.; Matsuo, H.; Murakami, H.; Sato, S.

    1988-01-01

    The diffuse brightness of the sky has been measured in six submillimeter passbands, using a rocket-borne, liquid helium-cooled, absolute radiometer. The flux measured at 1160 microns is in good agreement with the average of longer wavelength measurements of the temperature of the cosmic background radiation. The fluxes measured at 709 microns and 481 microns show a rapid decrease toward shorter wavelength, but correspond to significantly higher temperatures. No local source of this excess flux has been identified. The spectrum of the excess significantly constrains cosmological models. Data at 262, 137, and 102 microns are consistent with emission from interstellar dust.

  16. Maser radiometer for cosmic background radiation anisotropy measurements

    NASA Astrophysics Data System (ADS)

    Fixsen, D. J.; Wilkinson, D. T.

    1982-06-01

    A maser amplifier was incorporated into a low noise radiometer designed to measure large-scale anisotropy in the 3 deg K microwave background radiation. To minimize emission by atmospheric water vapor and oxygen, the radiometer is flown in a small balloon to an altitude to 25 km. Three successful flights were made - two from Palestine, Texas and one from Sao Jose dos Campos, Brazil. Good sky coverage is important to the experiment. Data from the northern hemisphere flights has been edited and calibrated.

  17. The cosmological microwave background radiation, cosmic and superconducting strings

    NASA Astrophysics Data System (ADS)

    Sanchez, N.; Signore, M.

    1989-03-01

    We study different kinds of anisotropies and distortions in the cosmological background radiation due to cosmic and superconducting strings: (i) temperature angular anisotropy by loop decay into gravitational waves and (ii) spectral distortions due to electromagnetic energy emission. We relate distortions produced by loops indifferent epochs of their evolution. We confront these predictions with observations, in particular with the submillimeter excess recently observed by the Nagoya-Berkeley experiment. This allows us to place constraints both of the string parameter Gμ and on the parameters governing loop evolution. UA 336 Laboratoire Associé au CNRS, Observatoire de Meudon et Ecole Normale Superieure, 24 reu Lhomond, F-75231 Paris Cedex 05, France.

  18. Maser radiometer for cosmic background radiation anisotropy measurements

    NASA Technical Reports Server (NTRS)

    Fixsen, D. J.; Wilkinson, D. T.

    1982-01-01

    A maser amplifier was incorporated into a low noise radiometer designed to measure large-scale anisotropy in the 3 deg K microwave background radiation. To minimize emission by atmospheric water vapor and oxygen, the radiometer is flown in a small balloon to an altitude to 25 km. Three successful flights were made - two from Palestine, Texas and one from Sao Jose dos Campos, Brazil. Good sky coverage is important to the experiment. Data from the northern hemisphere flights has been edited and calibrated.

  19. Distortion of the cosmic background radiation by superconducting strings

    NASA Technical Reports Server (NTRS)

    Ostriker, J. P.; Thompson, C.

    1987-01-01

    Superconducting cosmic strings can be significant energy sources, keeping the universe ionized past the commonly assumed epoch of recombination. As a result, the spectrum of the cosmic background radiation is distorted in the presence of heated primordial gas via the Suniaev-Zel'dovich effect. Thiis distortion can be relatively large: the Compton y parameter attains a maximum in the range 0.001-0.005, with these values depending on the mass scale of the string. A significant contribution to y comes from loops decaying at high redshift when the universe is optically thick to Thomson scattering. Moreover, the isotropic spectral distortion is large compared to fluctuations at all angular scales.

  20. A flat Universe from high-resolution maps of the cosmic microwave background radiation

    PubMed

    de Bernardis P; Ade; Bock; Bond; Borrill; Boscaleri; Coble; Crill; De Gasperis G; Farese; Ferreira; Ganga; Giacometti; Hivon; Hristov; Iacoangeli; Jaffe; Lange; Martinis; Masi; Mason; Mauskopf; Melchiorri; Miglio; Montroy; Netterfield

    2000-04-27

    The blackbody radiation left over from the Big Bang has been transformed by the expansion of the Universe into the nearly isotropic 2.73 K cosmic microwave background. Tiny inhomogeneities in the early Universe left their imprint on the microwave background in the form of small anisotropies in its temperature. These anisotropies contain information about basic cosmological parameters, particularly the total energy density and curvature of the Universe. Here we report the first images of resolved structure in the microwave background anisotropies over a significant part of the sky. Maps at four frequencies clearly distinguish the microwave background from foreground emission. We compute the angular power spectrum of the microwave background, and find a peak at Legendre multipole Ipeak = (197 +/- 6), with an amplitude delta T200 = (69 +/- 8) microK. This is consistent with that expected for cold dark matter models in a flat (euclidean) Universe, as favoured by standard inflationary models.

  1. A Flat Universe from High-Resolution Maps of the Cosmic MicrowaveBackground Radiation

    SciTech Connect

    de Bernardis, P.; Ade, P.A.R.; Bock, J.J.; Bond, J.R.; Borrill,J.; Boscaleri, A.; Coble, K.; Crill, B.P.; De Gasperis, G.; Farese, P.C.; Ferreira, P.G.; Ganga, K.; Giacometti, M.; Hivon, E.; Hristov, V.V.; Iacoangeli, A.; Jaffe, A.H.; Lange, A.E.; Martinis, L.; Masi, S.; Mason,P.; Mauskopf, P.D.; Melchiorri, A.; Miglio, L.; Montroy, T.; Netterfield,C.B.; Pascale, E.; Piacentini, F.; Pogosyan, D.; Prunet, S.; Rao, S.; Romeo, G.; Ruhl, J.E.; Scaramuzzi, F.; Sforna, D.; Vittorio, N.

    2000-04-28

    The blackbody radiation left over from the Big Bang has been transformed by the expansion of the Universe into the nearly isotropic 2.73 K Cosmic Microwave Background. Tiny inhomogeneities in the early Universe left their imprint on the microwave background in the form of small anisotropies in its temperature. These anisotropies contain information about basic cosmological parameters, particularly the total energy density and curvature of the universe. Here we report the first images of resolved structure in the microwave background anisotropies over a significant part of the sky. Maps at four frequencies clearly distinguish the microwave background from foreground emission. We compute the angular power spectrum of the microwave background, and find a peak at Legendre multipole {ell}{sub peak} = (197 {+-} 6), with an amplitude DT{sub 200} = (69 {+-} 8){mu}K. This is consistent with that expected for cold dark matter models in a flat (euclidean) Universe, as favored by standard inflationary scenarios.

  2. The cosmic microwave background: observing directly the early universe

    NASA Astrophysics Data System (ADS)

    de Bernardis, Paolo; Masi, Silvia

    2012-09-01

    The Cosmic Microwave Background (CMB) is a relict of the early universe. Its perfect 2.725K blackbody spectrum demonstrates that the universe underwent a hot, ionized early phase; its anisotropy (about 80 µK rms) provides strong evidence for the presence of photon-matter oscillations in the primeval plasma, shaping the initial phase of the formation of structures; its polarization state (about 3 µK rms), and in particular its rotational component (less than 0.1 µK rms) might allow to study the inflation process in the very early universe, and the physics of extremely high energies, impossible to reach with accelerators. The CMB is observed by means of microwave and mm-wave telescopes, and its measurements drove the development of ultra-sensitive bolometric detectors, sophisticated modulators, and advanced cryogenic and space technologies. Here we focus on the new frontiers of CMB research: the precision measurements of its linear polarization state, at large and intermediate angular scales, and the measurement of the inverse-Compton effect of CMB photons crossing clusters of Galaxies. In this framework, we will describe the formidable experimental challenges faced by ground-based, near-space and space experiments, using large arrays of detectors. We will show that sensitivity and mapping speed improvement obtained with these arrays must be accompanied by a corresponding reduction of systematic effects (especially for CMB polarimeters), and by improved knowledge of foreground emission, to fully exploit the huge scientific potential of these missions.

  3. A Comparison between High-Energy Radiation Background Models and SPENVIS Trapped-Particle Radiation Models

    NASA Technical Reports Server (NTRS)

    Krizmanic, John F.

    2013-01-01

    We have been assessing the effects of background radiation in low-Earth orbit for the next generation of X-ray and Cosmic-ray experiments, in particular for International Space Station orbit. Outside the areas of high fluxes of trapped radiation, we have been using parameterizations developed by the Fermi team to quantify the high-energy induced background. For the low-energy background, we have been using the AE8 and AP8 SPENVIS models to determine the orbit fractions where the fluxes of trapped particles are too high to allow for useful operation of the experiment. One area we are investigating is how the fluxes of SPENVIS predictions at higher energies match the fluxes at the low-energy end of our parameterizations. I will summarize our methodology for background determination from the various sources of cosmogenic and terrestrial radiation and how these compare to SPENVIS predictions in overlapping energy ranges.

  4. Large-Angular-Scale Anisotropy in the Cosmic Background Radiation

    DOE R&D Accomplishments Database

    Gorenstein, M. V.; Smoot, G. F.

    1980-05-01

    We report the results of an extended series of airborne measurements of large-angular-scale anisotropy in the 3 K cosmic background radiation. Observations were carried out with a dual-antenna microwave radiometer operating at 33 GHz (.089 cm wavelength) flown on board a U-2 aircraft to 20 km altitude. In eleven flights, between December 1976 and May 1978, the radiometer measured differential intensity between pairs of directions distributed over most of the northern hemisphere with an rms sensitivity of 47 mK Hz{sup 1�}. The measurements how clear evidence of anisotropy that is readily interpreted as due to the solar motion relative to the sources of the radiation. The anisotropy is well fit by a first order spherical harmonic of amplitude 360{+ or -}50km sec{sup -1} toward the direction 11.2{+ or -}0.5 hours of right ascension and 19 {+ or -}8 degrees declination. A simultaneous fit to a combined hypotheses of dipole and quadrupole angular distributions places a 1 mK limit on the amplitude of most components of quadrupole anisotropy with 90% confidence. Additional analysis places a 0.5 mK limit on uncorrelated fluctuations (sky-roughness) in the 3 K background on an angular scale of the antenna beam width, about 7 degrees.

  5. Ralph A. Alpher, Robert C. Herman, and the Cosmic Microwave Background Radiation

    NASA Astrophysics Data System (ADS)

    Alpher, Victor S.

    2012-09-01

    Much of the literature on the history of the prediction and discovery of the Cosmic Microwave Background Radiation (CMBR) is incorrect in some respects. I focus on the early history of the CMBR, from its prediction in 1948 to its measurement in 1964, basing my discussion on the published literature, the private papers of Ralph A. Alpher, and interviews with several of the major figures involved in the prediction and measurement of the CMBR. I show that the early prediction of the CMBR continues to be widely misunderstood.

  6. Early radiographic changes in radiation bone injury

    SciTech Connect

    Fujita, M.; Tanimoto, K.; Wada, T.

    1986-06-01

    A chronologic series of periapical radiographs was evaluated for the purpose of detecting damage to bone and tooth-supporting tissues in a patient receiving radiation therapy for a basal cell carcinoma of the mandibular gingiva. Widening of the periodontal space was one of the early radiographic changes observed. It is suggested, from the sequence of radiographic changes, that radiation-induced changed in the circulatory system of the bone might be primarily responsible for the resulting changes.

  7. Large-scale anisotropy of the cosmic microwave background radiation

    NASA Technical Reports Server (NTRS)

    Silk, J.; Wilson, M. L.

    1981-01-01

    Inhomogeneities in the large-scale distribution of matter inevitably lead to the generation of large-scale anisotropy in the cosmic background radiation. The dipole, quadrupole, and higher order fluctuations expected in an Einstein-de Sitter cosmological model have been computed. The dipole and quadrupole anisotropies are comparable to the measured values, and impose important constraints on the allowable spectrum of large-scale matter density fluctuations. A significant dipole anisotropy is generated by the matter distribution on scales greater than approximately 100 Mpc. The large-scale anisotropy is insensitive to the ionization history of the universe since decoupling, and cannot easily be reconciled with a galaxy formation theory that is based on primordial adiabatic density fluctuations.

  8. Dependence of the Radiation Pressure on the Background Refractive Index

    NASA Astrophysics Data System (ADS)

    Webb, Kevin J.

    2013-07-01

    The 1978 experiments by Jones and Leslie showing that the radiation pressure on a mirror depends on the background medium refractive index have yet to be adequately explained using a force model and have provided a leading challenge to the Abraham form of the electromagnetic momentum. Those experimental results are predicted for the first time using a force representation that incorporates the Abraham momentum by utilizing the power calibration method employed in the Jones and Leslie experiments. With an extension of the same procedure, the polarization and angle independence of the experimental data are also explained by this model. Prospects are good for this general form of the electromagnetic force density to be effective in predicting other experiments with macroscopic materials. Furthermore, the rigorous representation of material dispersion makes the representation important for metamaterials that operate in the vicinity of homogenized material resonances.

  9. Characterization of the radiation background at the Spallation Neutron Source

    NASA Astrophysics Data System (ADS)

    DiJulio, Douglas D.; Cherkashyna, Nataliia; Scherzinger, Julius; Khaplanov, Anton; Pfeiffer, Dorothea; Cooper-Jensen, Carsten P.; Fissum, Kevin G.; Kanaki, Kalliopi; Kirstein, Oliver; Ehlers, Georg; Gallmeier, Franz X.; Hornbach, Donald E.; Iverson, Erik B.; Newby, Robert J.; Hall-Wilton, Richard J.; Bentley, Phillip M.

    2016-09-01

    We present a survey of the radiation background at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory, TN, USA during routine daily operation. A broad range of detectors was used to characterize primarily the neutron and photon fields throughout the facility. These include a WENDI-2 extended range dosimeter, a thermoscientific NRD, an Arktis 4He detector, and a standard NaI photon detector. The information gathered from the detectors was used to map out the neutron dose rates throughout the facility and also the neutron dose rate and flux profiles of several different beamlines. The survey provides detailed information useful for developing future shielding concepts at spallation neutron sources, such as the European Spallation Source (ESS), currently under construction in Lund, Sweden.

  10. Far Infrared Spectrometry of the Cosmic Background Radiation

    DOE R&D Accomplishments Database

    Mather, J. C.

    1974-01-01

    I describe two experiments to measure the cosmic background radiation near 1 mm wavelength. The first was a ground-based search for spectral lines, made with a Fabry-Perot interferometer and an InSb detector. The second is a measurement of the spectrum from 3 to 18 cm{sup -1}, made with a balloon-borne Fourier transform spectrometer. It is a polarizing Michelson interferometer, cooled in liquid helium, and operated with a germanium bolometer. I give the theory of operation, construction details, and experimental results. The first experiment was successfully completed but the second suffered equipment malfunction on its first flight. I describe the theory of Fourier transformations and give a new understanding of convolutional phase correction computations. I discuss for infrared bolometer calibration procedures, and tabulate test results on nine detectors. I describe methods of improving bolometer sensitivity with immersion optics and with conductive film blackening.

  11. Radioactivity in the groundwater of a high background radiation area.

    PubMed

    Shabana, E I; Kinsara, A A

    2014-11-01

    Natural radioactivity was measured in groundwater samples collected from 37 wells scattered in an inhabited area of high natural background radiation, in a purpose of radiation protection. The study area is adjacent to Aja heights of granitic composition in Hail province, Saudi Arabia. Initial screening for gross α and gross β activities showed levels exceeded the national regulation limits set out for gross α and gross β activities in drinking water. The gross α activity ranged from 0.17 to 5.41 Bq L(-)(1) with an average value of 2.15 Bq L(-)(1), whereas gross β activity ranged from 0.48 to 5.16 Bq L(-)(1), with an average value of 2.60 Bq L(-)(1). The detail analyses indicated that the groundwater of this province is contaminated with uranium and radium ((226)Ra and (228)Ra). The average activity concentrations of (238)U, (234)U, (226)Ra and (228)Ra were 0.40, 0.77, 0.29 and 0.46 Bq L(-)(1), respectively. The higher uranium content was found in the samples of granitic aquifers, whereas the higher radium content was found in the samples of sandstone aquifers. Based on the obtained results, mechanism of leaching of the predominant radionuclides has been discussed in detail.

  12. Radioactivity in the groundwater of a high background radiation area.

    PubMed

    Shabana, E I; Kinsara, A A

    2014-11-01

    Natural radioactivity was measured in groundwater samples collected from 37 wells scattered in an inhabited area of high natural background radiation, in a purpose of radiation protection. The study area is adjacent to Aja heights of granitic composition in Hail province, Saudi Arabia. Initial screening for gross α and gross β activities showed levels exceeded the national regulation limits set out for gross α and gross β activities in drinking water. The gross α activity ranged from 0.17 to 5.41 Bq L(-)(1) with an average value of 2.15 Bq L(-)(1), whereas gross β activity ranged from 0.48 to 5.16 Bq L(-)(1), with an average value of 2.60 Bq L(-)(1). The detail analyses indicated that the groundwater of this province is contaminated with uranium and radium ((226)Ra and (228)Ra). The average activity concentrations of (238)U, (234)U, (226)Ra and (228)Ra were 0.40, 0.77, 0.29 and 0.46 Bq L(-)(1), respectively. The higher uranium content was found in the samples of granitic aquifers, whereas the higher radium content was found in the samples of sandstone aquifers. Based on the obtained results, mechanism of leaching of the predominant radionuclides has been discussed in detail. PMID:25087070

  13. Investigation of background radiation and associated anomalies in Rifle, Colorado

    SciTech Connect

    Smuin, D.R.; Wilson, M.J.; Crutcher, J.W.

    1988-02-01

    In addition to examining anomalies and establishing the background gamma exposure rate range, the study presents a formula to convert thousand counts per minute (kcpm) from a gamma scintillator to microroentgen per hour (..mu..Rh) for the Rifle region. Also, a method is presented to identify contaminated areas containing excess /sup 226/Ra, by using a GR-410 gamma spectrometer. This method is suggested to be applied to all property surveys in the Rifle area. The Wasatch Formation, which outcrops extensively in the Rifle area, was found to have a major influence on the background radiation. Varying potassium concentrations and naturally occurring uranium in this rock unit reveal varying gamma exposure rates. Examining RaTh ratios from laboratory analysis of soil samples or use of RaTh ratios from GR-410 gamma spectrometer readings on site allows discrimination between mill related contamination and naturally occuring radioactivity. Radioactive coal clinkers were found used as fill material throughout the Rifle region and have been determined to be a product of the mill and subject to remediation. Finally, windblown mill tailings contamination is addressed in some detail. Mill tailings redistributed from the Rifle uranium mill tailings piles by prevailing winds were detected extensively on vicinity properties in Rifle. Some radioactive components of the windblown tailings were found to have leached into the subsurface soil. The combination of Wasatch Formation, radioactive coal clinkers, and windblown tailings accounts for many of the anomalous gamma exposure rates observed by the radiological survey teams. 11 refs., 10 figs., 3 tabs

  14. The grand unified photon spectrum: A coherent view of the diffuse extragalactic background radiation

    NASA Technical Reports Server (NTRS)

    Ressell, M. Ted; Turner, Michael S.

    1989-01-01

    The spectrum of diffuse extragalactic background radiation (DEBRA) at wavelengths from 10(exp 5) to 10(exp -24) cm is presented in a coherent fashion. Each wavelength region, from the radio to ultra-high energy photons and cosmic rays, is treated both separately and as part of the grand unified photon spectrum (GUPS). A discussion of, and references to, the relevant literature for each wavelength region is included. This review should provide a useful tool for those interested in diffuse backgrounds, the epoch of galaxy formation, astrophysical/cosmological constraints to particle properties, exotic early Universe processes, and many other astrophysical and cosmological enterprises. As a worked example, researchers derive the cosmological constraints to an unstable-neutrino spies (with arbitrary branching ratio to a radiative decay mode) that follow from the GUPS.

  15. The origin and early radiation of dinosaurs

    NASA Astrophysics Data System (ADS)

    Brusatte, Stephen L.; Nesbitt, Sterling J.; Irmis, Randall B.; Butler, Richard J.; Benton, Michael J.; Norell, Mark A.

    2010-07-01

    Dinosaurs were remarkably successful during the Mesozoic and one subgroup, birds, remain an important component of modern ecosystems. Although the extinction of non-avian dinosaurs at the end of the Cretaceous has been the subject of intense debate, comparatively little attention has been given to the origin and early evolution of dinosaurs during the Late Triassic and Early Jurassic, one of the most important evolutionary radiations in earth history. Our understanding of this keystone event has dramatically changed over the past 25 years, thanks to an influx of new fossil discoveries, reinterpretations of long-ignored specimens, and quantitative macroevolutionary analyses that synthesize anatomical and geological data. Here we provide an overview of the first 50 million years of dinosaur history, with a focus on the large-scale patterns that characterize the ascent of dinosaurs from a small, almost marginal group of reptiles in the Late Triassic to the preeminent terrestrial vertebrates of the Jurassic and Cretaceous. We provide both a biological and geological background for early dinosaur history. Dinosaurs are deeply nested among the archosaurian reptiles, diagnosed by only a small number of characters, and are subdivided into a number of major lineages. The first unequivocal dinosaurs are known from the late Carnian of South America, but the presence of their sister group in the Middle Triassic implies that dinosaurs possibly originated much earlier. The three major dinosaur lineages, theropods, sauropodomorphs, and ornithischians, are all known from the Triassic, when continents were joined into the supercontinent Pangaea and global climates were hot and arid. Although many researchers have long suggested that dinosaurs outcompeted other reptile groups during the Triassic, we argue that the ascent of dinosaurs was more of a matter of contingency and opportunism. Dinosaurs were overshadowed in most Late Triassic ecosystems by crocodile-line archosaurs and

  16. A map of the cosmic background radiation at 3 millimeters

    NASA Technical Reports Server (NTRS)

    Lubin, P.; Villela, T.; Epstein, G.; Smoot, G.

    1985-01-01

    Data from a series of balloon flights covering both the Northern and Southern Hemispheres, measuring the large angular scale anisotropy in the cosmic background radiation at 3.3 mm wavelength are presented. The data cover 85 percent of the sky to a limiting sensitivity of 0.7 mK per 7 deg field of view. The data show a 50-sigma (statistical error only) dipole anisotropy with an amplitude of 3.44 + or - 0.17 mK and a direction of alpha = 11.2 h + or - 0.1 h, and delta = -6.0 deg + or - 1.5 deg. A 90 percent confidence level upper limit of 0.00007 is obtained for the rms quadrupole amplitude. Flights separated by 6 months show the motion of earth around the sun. Galactic contamination is very small, with less than 0.1 mK contribution to the dipole quadrupole terms. A map of the sky has been generated from the data.

  17. Measuring the large-scale anisotropy in the microwave background radiation

    NASA Technical Reports Server (NTRS)

    Wilkinson, D. T.

    1982-01-01

    Measurements of large-scale anisotropy in the 2.7 K microwave background radiation are reaching a sensitivity of Delta T/T = 0.0001 in the amplitudes of low-order spherical harmonics. At this level, interesting conditions and processes in the early universe can be studied. However, the measurements are difficult and very susceptible to systematic errors. The microwave instruments and techniques are discussed with the emphasis on the reduction and evaluation of spurious effects. The subtraction of foreground radiation, mainly from diffuse Galactic sources, is a major problem that already limits the accuracy of measurements near 1 cm wavelength. Current results for the dipole and quadrupole moments are compared and discussed.

  18. Human response to high-background radiation environments on Earth and in space

    NASA Astrophysics Data System (ADS)

    Durante, M.; Manti, L.

    2008-09-01

    The main long-term objective of the space exploration program is the colonization of the planets of the Solar System. The high cosmic radiation equivalent dose rate represents an inescapable problem for the safe establishment of permanent human settlements on these planets. The unshielded equivalent dose rate on Mars ranges between 100 and 200 mSv/year, depending on the Solar cycle and altitude, and can reach values as high as 360 mSv/year on the Moon. The average annual effective dose on Earth is about 3 mSv, nearly 85% of which comes from natural background radiation, reduced to less than 1 mSv if man-made sources and the internal exposure to Rn daughters are excluded. However, some areas on Earth display anomalously high levels of background radiation, as is the case with thorium-rich monazite bearing sand deposits where values 200 400 times higher than the world average can be found. About 2% of the world’s population live above 3 km and receive a disproportionate 10% of the annual effective collective dose due to cosmic radiation, with a net contribution to effective dose by the neutron component which is 3 4 fold that at sea level. Thus far, epidemiological studies have failed to show any adverse health effects in the populations living in these terrestrial high-background radiation areas (HBRA), which provide an unique opportunity to study the health implications of an environment that, as closely as possibly achievable on Earth, resembles the chronic exposure of future space colonists to higher-than-normal levels of ionizing radiation. Chromosomal aberrations in the peripheral blood lymphocytes from the HBRA residents have been measured in several studies because chromosomal damage represents an early biomarker of cancer risk. Similar cytogenetic studies have been recently performed in a cohort of astronauts involved in single or repeated space flights over many years. The cytogenetic findings in populations exposed to high dose-rate background radiation

  19. On the radiative and thermodynamic properties of the cosmic radiations using COBE FIRAS instrument data: I. Cosmic microwave background radiation

    NASA Astrophysics Data System (ADS)

    Fisenko, Anatoliy I.; Lemberg, Vladimir

    2014-07-01

    Using the explicit form of the functions to describe the monopole and dipole spectra of the Cosmic Microwave Background (CMB) radiation, the exact expressions for the temperature dependences of the radiative and thermodynamic functions, such as the total radiation power per unit area, total energy density, number density of photons, Helmholtz free energy density, entropy density, heat capacity at constant volume, and pressure in the finite range of frequencies v 1≤ v≤ v 2 are obtained. Since the dependence of temperature upon the redshift z is known, the obtained expressions can be simply presented in z representation. Utilizing experimental data for the monopole and dipole spectra measured by the COBE FIRAS instrument in the 60-600 GHz frequency interval at the temperature T=2.72548 K, the values of the radiative and thermodynamic functions, as well as the radiation density constant a and the Stefan-Boltzmann constant σ are calculated. In the case of the dipole spectrum, the constants a and σ, and the radiative and thermodynamic properties of the CMB radiation are obtained using the mean amplitude T amp=3.358 mK. It is shown that the Doppler shift leads to a renormalization of the radiation density constant a, the Stefan-Boltzmann constant σ, and the corresponding constants for the thermodynamic functions. The expressions for new astrophysical parameters, such as the entropy density/Boltzmann constant, and number density of CMB photons are obtained. The radiative and thermodynamic properties of the Cosmic Microwave Background radiation for the monopole and dipole spectra at redshift z≈1089 are calculated.

  20. Limit on the energy density in the submillimetre background radiation.

    NASA Technical Reports Server (NTRS)

    Cowsik, R.

    1972-01-01

    An analysis is made which indicates that the energy density in the submillimeter quanta cannot exceed about 0.4 eV/cu cm averaged over the galactic dimensions, independent of the exact spectral distribution of this radiation. This corresponds to an upper limit of 3.4 K on the radiation temperature in the galactic neighborhood.

  1. Human exposure to high natural background radiation: what can it teach us about radiation risks?

    PubMed Central

    Hendry, Jolyon H; Simon, Steven L; Wojcik, Andrzej; Sohrabi, Mehdi; Burkart, Werner; Cardis, Elisabeth; Laurier, Dominique; Tirmarche, Margot; Hayata, Isamu

    2014-01-01

    Natural radiation is the major source of human exposure to ionising radiation, and its largest contributing component to effective dose arises from inhalation of 222Rn and its radioactive progeny. However, despite extensive knowledge of radiation risks gained through epidemiologic investigations and mechanistic considerations, the health effects of chronic low-level radiation exposure are still poorly understood. The present paper reviews the possible contribution of studies of populations living in high natural background radiation (HNBR) areas (Guarapari, Brazil; Kerala, India; Ramsar, Iran; Yangjiang, China), including radon-prone areas, to low dose risk estimation. Much of the direct information about risk related to HNBR comes from case–control studies of radon and lung cancer, which provide convincing evidence of an association between long-term protracted radiation exposures in the general population and disease incidence. The success of these studies is mainly due to the careful organ dose reconstruction (with relatively high doses to the lung), and to the fact that large-scale collaborative studies have been conducted to maximise the statistical power and to ensure the systematic collection of information on potential confounding factors. In contrast, studies in other (non-radon) HNBR areas have provided little information, relying mainly on ecological designs and very rough effective dose categorisations. Recent steps taken in China and India to establish cohorts for follow-up and to conduct nested case–control studies may provide useful information about risks in the future, provided that careful organ dose reconstruction is possible and information is collected on potential confounding factors. PMID:19454802

  2. North Dakota Early Childhood Tracking System - Background Memorandum.

    ERIC Educational Resources Information Center

    North Dakota State Legislative Council, Bismarck.

    This report responds to a North Dakota legislative mandate to study the state's early childhood tracking system for children who are at risk for developmental delays. Introductory sections summarize critical definitions and relevant federal legislation (specifically Part H of Public Law 99-457). The North Dakota program is then reviewed. Nineteen…

  3. Modeling Early Galaxies Using Radiation Hydrodynamics

    SciTech Connect

    2011-01-01

    This simulation uses a flux-limited diffusion solver to explore the radiation hydrodynamics of early galaxies, in particular, the ionizing radiation created by Population III stars. At the time of this rendering, the simulation has evolved to a redshift of 3.5. The simulation volume is 11.2 comoving megaparsecs, and has a uniform grid of 10243 cells, with over 1 billion dark matter and star particles. This animation shows a combined view of the baryon density, dark matter density, radiation energy and emissivity from this simulation. The multi-variate rendering is particularly useful because is shows both the baryonic matter ("normal") and dark matter, and the pressure and temperature variables are properties of only the baryonic matter. Visible in the gas density are "bubbles", or shells, created by the radiation feedback from young stars. Seeing the bubbles from feedback provides confirmation of the physics model implemented. Features such as these are difficult to identify algorithmically, but easily found when viewing the visualization. Simulation was performed on Kraken at the National Institute for Computational Sciences. Visualization was produced using resources of the Argonne Leadership Computing Facility at Argonne National Laboratory.

  4. Analysis of Nuclear Reactor Background Radiation for Neutrino Experiments

    NASA Astrophysics Data System (ADS)

    Leblanc, Ricky; Blackmon, J. C.; Rasco, B. C.; Mumm, H. P.; mTC; NuLat Collaboration

    2015-10-01

    Prior measurements of reactor antineutrinos have found a lower flux than expected. Precision measurements of antineutrino energy spectra are important for understanding the anomaly, reactor safeguards, and nuclear nonproliferation. Antineutrino detector designs rely on good characterization of gamma-ray and neutron backgrounds near the reactor core. To study the gamma-ray background at the NIST research reactor, spectra were collected using a 6.25 cm diameter × 5.5 cm germanium detector. We analyzed the measured spectra using simulations of the detector response using the GEANT4 toolkit to determine background fluxes and build a background model that will be used to understand shielding requirements and the impact of backgrounds on potential short-baseline reactor antineutrino studies at NIST. This work supported by the National Science Foundation and LSU.

  5. Rain-induced increase in background radiation detected by Radiation Portal Monitors.

    PubMed

    Livesay, R J; Blessinger, C S; Guzzardo, T F; Hausladen, P A

    2014-11-01

    A complete understanding of both the steady state and transient background measured by Radiation Portal Monitors (RPMs) is essential to predictable system performance, as well as maximization of detection sensitivity. To facilitate this understanding, a test bed for the study of natural background in RPMs has been established at the Oak Ridge National Laboratory. This work was performed in support of the Second Line of Defense Program's mission to enhance partner country capability to deter, detect, and interdict the illicit movement of special nuclear material. In the present work, transient increases in gamma-ray counting rates in RPMs due to rain are investigated. The increase in background activity associated with rain, which has been well documented in the field of environmental radioactivity, originates primarily from the wet-deposition of two radioactive daughters of (222)Rn, namely, (214)Pb and (214)Bi. In this study, rainfall rates recorded by a co-located weather station are compared with RPM count rates and high-purity germanium spectra. The data verify that these radionuclides are responsible for the largest environmental background fluctuations in RPMs. Analytical expressions for the detector response function in Poly-Vinyl Toluene have been derived. Effects on system performance and potential mitigation strategies are discussed.

  6. Rain-Induced Increase in Background Radiation Detected by Radiation Portal Monitors

    SciTech Connect

    Hausladen, Paul; Blessinger, Christopher S; Guzzardo, Tyler; Livesay, Jake

    2012-07-01

    A complete understanding of both the steady state and transient background measured by Radiation Portal Monitors (RPMs) is essential to predictable system performance, as well as maximization of detection sensitivity. To facilitate this understanding, a test bed for the study of natural background in RPMs has been established at the Oak Ridge National Laboratory. This work was performed in support of the Second Line of Defense Program's mission to detect the illicit movement of nuclear material. In the present work, transient increases in gamma ray counting rates in RPMs due to rain are investigated. The increase in background activity associated with rain, which has been well documented in the field of environmental radioactivity, originates from the atmospheric deposition of two radioactive daughters of radon-222, namely lead-214 and bismuth-214 (henceforth {sup 222}Rn, {sup 214}Pb and {sup 214}Bi). In this study, rainfall rates recorded by a co-located weather station are compared with RPM count rates and High Purity Germanium spectra. The data verifies these radionuclides are responsible for the dominant transient natural background fluctuations in RPMs. Effects on system performance and potential mitigation strategies are discussed.

  7. Radiation Background and Attenuation Model Validation and Development

    SciTech Connect

    Peplow, Douglas E.; Santiago, Claudio P.

    2015-08-05

    This report describes the initial results of a study being conducted as part of the Urban Search Planning Tool project. The study is comparing the Urban Scene Simulator (USS), a one-dimensional (1D) radiation transport model developed at LLNL, with the three-dimensional (3D) radiation transport model from ORNL using the MCNP, SCALE/ORIGEN and SCALE/MAVRIC simulation codes. In this study, we have analyzed the differences between the two approaches at every step, from source term representation, to estimating flux and detector count rates at a fixed distance from a simple surface (slab), and at points throughout more complex 3D scenes.

  8. Hawking's radiation in non-stationary rotating de Sitter background

    NASA Astrophysics Data System (ADS)

    Ibohal, N.; Ibungochouba, T.

    2011-05-01

    Hawking's radiation effect of Klein-Gordon scalar field, Dirac particles and Maxwell's electromagnetic field in the non-stationary rotating de Sitter cosmological space-time is investigated by using a method of generalized tortoise co-ordinates transformation. The locations and the temperatures of the cosmological horizons of the non-stationary rotating de Sitter model are derived. It is found that the locations and the temperatures of the rotating cosmological model depend not only on the time but also on the angle. The stress-energy regularization techniques are applied to the two dimensional analog of the de Sitter metrics and the calculated stress-energy tensor contains the thermal radiation effect.

  9. Detecting a Non-Gaussian Stochastic Background of Gravitational Radiation

    NASA Astrophysics Data System (ADS)

    Drasco, Steve; Flanagan, Éanna É.

    2002-12-01

    We derive a detection method for a stochastic background of gravitational waves produced by events where the ratio of the average time between events to the average duration of an event is large. Such a signal would sound something like popcorn popping. Our derivation is based on the somewhat unrealistic assumption that the duration of an event is smaller than the detector time resolution.

  10. Influence on cell proliferation of background radiation or exposure to very low, chronic gamma radiation. [Paramecium tetraurelia; Synechococcus lividus

    SciTech Connect

    Planel, H.; Soleilhavoup, J.P.; Tixador, R.; Richoilley, G.; Conter, A.; Croute, F.; Caratero, C.; Gaubin, Y.

    1987-05-01

    Investigations carried out on the protozoan Paramecium tetraurelia and the cyanobacteria Synechococcus lividus, which were shielded against background radiation or exposed to very low doses of gamma radiation, demonstrated that radiation can stimulate the proliferation of these two single-cell organisms. Radiation hormesis depends on internal factors (age of starting cells) and external factors (lighting conditions). The stimulatory effect occurred only in a limited range of doses and disappeared for dose rates higher than 50 mGy/y.

  11. Background radiation of the territory of some military objectives in Georgia.

    PubMed

    Jorbenadze, M

    2005-01-01

    Background radiation on the territory of some military objects in Georgia has been investigated with the help of "DRPB-03" (dosimeter-radiometer) according to the specially created instruction. Background radiation of investigated objects varied from 0,09 to 0,28 mkZv/h; in average 0,18 mkZv/h. The maximal level was measured on the 8th object -0,28 mkZv/h, minimal on the 2nd object -0,09 mkZv/h, in average near the - 0,18 mkZv/h. The maximal level of the annual doze of radiation was measured on the 8th object -0,49 mZv/y; and minimal on the 2nd -0,15 mZv/y. The analysis of investigations showed, that the level of background radiation on the territory of the investigated military objects exceeds the level of European countries and South Caucasus (except Armenia). This could be explained by the peculiarities of our country: geomorphological structure and disposition of soil (altitude, latitude). These reasons could cause the high levels of natural background radiation. The level of background radiation is higher in Black Sea coast area, which may be the result of the Chernobyl Accident (contamination with artificial radionuclides). The comparatively high level of background radiation indicates that the personnel sustain relatively high radiation doses from natural radiation origins. PMID:15821332

  12. Conference on the High Energy Radiation Background in Space, held in conjunction with IEEE Nuclear and Space Radiation Effects Conference. Workshop record.

    NASA Astrophysics Data System (ADS)

    The following topics were dealt with: the high energy radiation background in space, cosmic rays, solar particle events, gamma-ray astronomical telescopes, detector noise due to background radiations, semiconductor particle counters, magnetosphere and radiation belts.

  13. Dark energy and the cosmic microwave background radiation

    NASA Technical Reports Server (NTRS)

    Dodelson, S.; Knox, L.

    2000-01-01

    We find that current cosmic microwave background anisotropy data strongly constrain the mean spatial curvature of the Universe to be near zero, or, equivalently, the total energy density to be near critical-as predicted by inflation. This result is robust to editing of data sets, and variation of other cosmological parameters (totaling seven, including a cosmological constant). Other lines of argument indicate that the energy density of nonrelativistic matter is much less than critical. Together, these results are evidence, independent of supernovae data, for dark energy in the Universe.

  14. Dark energy and the cosmic microwave background radiation.

    PubMed

    Dodelson, S; Knox, L

    2000-04-17

    We find that current cosmic microwave background anisotropy data strongly constrain the mean spatial curvature of the Universe to be near zero, or, equivalently, the total energy density to be near critical-as predicted by inflation. This result is robust to editing of data sets, and variation of other cosmological parameters (totaling seven, including a cosmological constant). Other lines of argument indicate that the energy density of nonrelativistic matter is much less than critical. Together, these results are evidence, independent of supernovae data, for dark energy in the Universe.

  15. A measurement of the low frequency spectrum of the cosmic microwave background radiation

    SciTech Connect

    Levin, S.M.

    1987-04-01

    As part of a larger effort to measure the spectrum of the Cosmic Background Radiation (CBR) at low frequencies, the intensity of the CBR has been measured at a frequency of 1.410 GHz. The measurement was made by comparing the power received from the sky with the power received from a specially designed cooled calibration target with known properties. Sources of radiation other than the CBR were then identified and subtracted to calculate the antenna temperature of the CBR at 1.410 GHz. The instrument used to measure the CBR was a total-power microwave radiometer with a 25 MHz bandwidth centered at 1.410 GHz. The radiometer had a noise temperature of 80 K, and sufficient data were taken that radiometer noise did not contribute significantly to the total measurement error. The sources of error were predominantly systematic in nature, and the largest error was due to uncertainty in the reflection characteristics of the cold-load calibrator. Identification and subtraction of signals from the Galaxy (0.7 K) and the Earth's atmosphere (0.8 K) were also significant parts of the data reduction and error analysis. The brightness temperature of the Cosmic Background Radiation at 1.410 GHz is 222. +- 0.55 Kelvin. The spectrum of the CBR, as determined by this measurement and other published results, is consistent with a blackbody spectrum of temperature 2.741 +- 0.016. Constraints on the amount by which the CBR spectrum deviates from Planck spectrum are used to place limits on energy releases early in the history of the universe. 55 refs., 25 figs., 8 tabs.

  16. Fast shutter for low background radiation environments at SPR III

    SciTech Connect

    Kelly, J.G.; Sites, K.; Scott, W.

    1994-08-01

    A fast shutter system has been developed and used to isolate experiments from the radiation emitted after the main pulse of the Sandia Pulse Reactor, SPR 3. In about 15 ms the system moves a massive 20 kg shield in front of the beam port aperture in the facility shield wall. A second gravity-driven shutter is dropped into place in about 200 ms. The total attenuation achieved in the beam intensity is about a factor of one hundred. The shutter assembly was used, along with a sensitive detection system, to observe the gamma ray flux emitted by various materials activated by the neutron beam at levels nine orders of magnitude smaller than the gamma flux level at the target during the reactor pulse.

  17. Spectral observations of the extreme ultraviolet astronomical background radiation

    NASA Technical Reports Server (NTRS)

    Labov, S.; Bowyer, S.

    1988-01-01

    Observations in the FUV and soft X-ray bands suggest that the ISM contains several components of high-temperature gas (100,000-1 million K). If large volumes of local interstellar space are filled with this hot plasma, emission lines will be produced in the EUV. Diffuse EUV radiation, however, has only been detected with photometric instruments; no spectral measurements exist below 520 A. A unique grazing-incidence spectrometer to study the diffuse emission between 80 and 650 A with resolution 10-30 A was successfully flown on a sounding rocket in April 1986, and a preliminary analysis reveals several features. In addition to the expected interplanetary He I 584 A emission and the geocoronal He II 304 A emission, other features appear which may orginate in the hot ionized interstellar gas.

  18. Division G Commission 21: Galactic and Extragalactic Backgrounds Radiation

    NASA Astrophysics Data System (ADS)

    Murthy, Jayant; Witt, Adolf; Baggaley, W. Jack; Dwek, Eli; Levasseur-Regourd, Anny-Chantal; Mann, Ingrid; Mattila, Kalevi; Watanabe, Jun-Ichi

    2016-04-01

    Commission 21 was one of the oldest and smallest in the IAU yet one which underwent the most evolution since its inception. It began in 1955 as Light of the Night Sky (Lumière du Ciel Nocturne) under the Presidentship of Jean Dufay (University Observatory at Lyon). As the name suggested, in the years before space observations, its focus was on observations of atmospheric light which, at the time, was the domain of astronomers. Thus the early proceedings of the Commission were dominated by reports of the daytime and nighttime emission as observed from different locations and different conditions. Our knowledge of the Earth's atmosphere is still shaped by these early observations (Meier R.R., 1991, Space Sci. Rev. 58, 1). Members of Commission 21 were key to organizing interational collaborations to set up atmospheric stations at different latitudes, including in the Souther hemisphere and in ensuring a consistent calibration between the instruments. The Commission also bought in results from Soviet scientists in an era where communication was limited by both politics and language.

  19. Modeling Background Radiation in our Environment Using Geochemical Data

    SciTech Connect

    Malchow, Russell L.; Marsac, Kara; Burnley, Pamela; Hausrath, Elisabeth; Haber, Daniel; Adcock, Christopher

    2015-02-01

    Radiation occurs naturally in bedrock and soil. Gamma rays are released from the decay of the radioactive isotopes K, U, and Th. Gamma rays observed at the surface come from the first 30 cm of rock and soil. The energy of gamma rays is specific to each isotope, allowing identification. For this research, data was collected from national databases, private companies, scientific literature, and field work. Data points were then evaluated for self-consistency. A model was created by converting concentrations of U, K, and Th for each rock and soil unit into a ground exposure rate using the following equation: D=1.32 K+ 0.548 U+ 0.272 Th. The first objective of this research was to compare the original Aerial Measurement System gamma ray survey to results produced by the model. The second objective was to improve the method and learn the constraints of the model. Future work will include sample data analysis from field work with a goal of improving the geochemical model.

  20. Reduction of the Background Magnetic Field Inhibits Ability of Drosophila melanogaster to Survive Ionizing Radiation

    PubMed Central

    Portelli, Lucas; Madapatha, Dinu; Martino, Carlos; Hernandez, Mark; Barnes, Frank

    2012-01-01

    The effects of exposure to an environment where the background magnetic field has been reduced were studied on wild-type Drosophila melanogaster by measuring its ability to survive a single exposure to ionizing radiation during its larval stage. The experimental design presented shows a timeframe, ionizing radiation dose and background magnetic field parameters that will cause a significant and reproducible reduction of survival on this insect model. These results suggest that background magnetic fields may play a fundamental role in the recovery or harm of a biological system that is exposed to single doses of ionizing radiation. PMID:22532126

  1. Observations of the cosmic background radiation at 1440 angstroms

    NASA Technical Reports Server (NTRS)

    Paresco, F.; Bowyer, S.; Lampton, M.; Margon, B.

    1979-01-01

    A survey of the summer night sky in the 1350-1550-A band at 2.5-deg angular resolution was carried out with a far-ultraviolet channel of the Berkeley Extreme Ultraviolet (EUV) telescope on the Apollo-Soyuz mission. The large collecting area and small field of view of this telescope permitted the identification and removal from the data of individual stars of spectral type A2 or earlier with visual magnitude brighter than about 6.5. A residual signal significantly above background remains which is not of terrestrial or interplanetary origin and varies with view direction between approximately 30 and 2000 counts/s. The source of the emission is observed to be highly concentrated to the galactic plane with a distribution of half-width about 10 deg centered on the plane and a roughly constant-intensity tail extending out to both galactic poles. The minimum signal detected at high and moderate latitudes corresponds to 300 + or - 60 photons/sq cm-s-sr-A. This minimum flux may be due to scattering from interstellar dust, or it may be extragalactic in origin.

  2. The Cosmic Background Radiation circa ν2K

    NASA Astrophysics Data System (ADS)

    Bond, J. Richard; Pogosyan, Dmitry; Prunet, Simon

    We describe the implications of cosmic microwave background (CMB) observations and galaxy and cluster surveys of large scale structure (LSS) for theories of cosmic structure formation, especially emphasizing the recent Boomerang and Maxima CMB balloon experiments. The inflation-based cosmic structure formation paradigm we have been operating with for two decades has never been in better shape. Here we primarily focus on a simplified inflation parameter set, {ωb, ωcdm, Ωtot, ΩΛ, ns, τC, σ8}. Combining all of the current CMB+LSS data points to the remarkable conclusion that the local Hubble patch we can access has little mean curvature (Ωtot = 1.08 +/- 0.06) and the initial fluctuations were nearly scale invariant (ns = 1.03 +/- 0.08), both predictions of (non-baroque) inflation theory. The baryon density is found to be slightly larger than that preferred by independent Big Bang Nucleosynthesis estimates (ωb --- Ωbh2 = 0.030 +/- 0.005 cf. 0.019 +/- 0.002). The CDM density is in the expected range (ωcdm = 0.17+/-0.02). Even stranger is the CMB+LSS evidence that the density of the universe is dominated by unclustered energy akin to the cosmological constant (ΩΛ = 0.66 +/- 0.06), at the same level as that inferred from high redshift supernova observations. We also sketch the CMB+LSS implications for massive neutrinos.

  3. State background-radiation levels: results of measurements taken during 1975-1979

    SciTech Connect

    Myrick, T.E.; Berven, B.A.; Haywood, F.F.

    1981-11-01

    Background radiation levels across the United States have been measured by the Off-Site Pollutant Measurements Group of the Health and Safety Research Division at Oak Ridge National Laboratory (ORNL). These measurements have been conducted as part of the ORNL program of radiological surveillance at inactive uranium mills and sites formerly utilized during Manhattan Engineer District and early Atomic Energy Commission projects. The measurements included determination of /sup 226/Ra, /sup 232/Th, and /sup 238/U concentrations in surface soil samples and measurement of external gamma-ray exposure rates at 1 m above the ground surface at the location of soil sampling. This information is being utilized for comparative purposes to determine the extent of contamination present at the survey sites and surrounding off-site areas. The sampling program to date has provided background information at 356 locations in 33 states. External gamma-ray exposure rates were found to range from less than 1 to 34 ..mu..R/h, with an US average of 8.5 ..mu..R/h. The nationwide average concentrations of /sup 226/Ra, /sup 232/Th, and /sup 238/U in surface soil were determined to be 1.1, 0.98, and 1.0 pCi/g, respectively.

  4. THE HIGH BACKGROUND RADIATION AREA IN RAMSAR IRAN: GEOLOGY, NORM, BIOLOGY, LNT, AND POSSIBLE REGULATORY FUN

    SciTech Connect

    Karam, P. A.

    2002-02-25

    The city of Ramsar Iran hosts some of the highest natural radiation levels on earth, and over 2000 people are exposed to radiation doses ranging from 1 to 26 rem per year. Curiously, inhabitants of this region seem to have no greater incidence of cancer than those in neighboring areas of normal background radiation levels, and preliminary studies suggest their blood cells experience fewer induced chromosomal abnormalities when exposed to 150 rem ''challenge'' doses of radiation than do the blood cells of their neighbors. This paper will briefly describe the unique geology that gives Ramsar its extraordinarily high background radiation levels. It will then summarize the studies performed to date and will conclude by suggesting ways to incorporate these findings (if they are borne out by further testing) into future radiation protection standards.

  5. A method to characterise site, urban and regional ambient background radiation.

    PubMed

    Passmore, C; Kirr, M

    2011-03-01

    Control dosemeters are routinely provided to customers to monitor the background radiation so that it can be subtracted from the gross response of the dosemeter to arrive at the occupational dose. Landauer, the largest dosimetry processor in the world with subsidiaries in Australia, Brazil, China, France, Japan, Mexico and the UK, has clients in approximately 130 countries. The Glenwood facility processes over 1.1 million controls per year. This network of clients around the world provides a unique ability to monitor the world's ambient background radiation. Control data can be mined to provide useful historical information regarding ambient background rates and provide a historical baseline for geographical areas. Historical baseline can be used to provide site or region-specific background subtraction values, document the variation in ambient background radiation around a client's site or provide a baseline for measuring the efficiency of clean-up efforts in urban areas after a dirty bomb detonation.

  6. A method to characterise site, urban and regional ambient background radiation.

    PubMed

    Passmore, C; Kirr, M

    2011-03-01

    Control dosemeters are routinely provided to customers to monitor the background radiation so that it can be subtracted from the gross response of the dosemeter to arrive at the occupational dose. Landauer, the largest dosimetry processor in the world with subsidiaries in Australia, Brazil, China, France, Japan, Mexico and the UK, has clients in approximately 130 countries. The Glenwood facility processes over 1.1 million controls per year. This network of clients around the world provides a unique ability to monitor the world's ambient background radiation. Control data can be mined to provide useful historical information regarding ambient background rates and provide a historical baseline for geographical areas. Historical baseline can be used to provide site or region-specific background subtraction values, document the variation in ambient background radiation around a client's site or provide a baseline for measuring the efficiency of clean-up efforts in urban areas after a dirty bomb detonation. PMID:20959341

  7. Cosmic gravitational background radiation as a basis of Karolyhazy hazy space-time

    NASA Astrophysics Data System (ADS)

    Ma, Guang-Wen

    1998-03-01

    It is argued that the Karolyhazy hazy space-time should be related with the cosmic gravitational background radiation. A scheme to establish their relation is proposed. The Diosi-Lukacs type electromagnetic radiation is re-calculated. The result is smaller by 57 orders of magnitude than that of Diosi and Lukacs.

  8. The Cow on the High Street: Effects of Background Context on Early Naming

    ERIC Educational Resources Information Center

    Meints, Kerstin; Plunkett, Kim; Harris, Paul L.; Dimmock, Debbie

    2004-01-01

    What role does contextual information play in children's early word comprehension? Using an inter-modal preferential looking task, we investigated how different background contexts influence children's looking times before and after an image has been named. Prior to the experiment, early comprehension of words was assessed using parental…

  9. Genetic background influences loss of heterozygosity patterns in radiation-induced mouse thymic lymphoma

    PubMed Central

    Hang, Michael; Huang, Yurong; Snijders, Antoine M.; Mao, Jian-Hua

    2015-01-01

    Previous studies have revealed that p53 heterozygous (p53+/−) mice are extremely susceptible to radiation-induced tumorigenesis. To investigate whether genetic background influences radiation induced tumor susceptibility, we crossed p53+/− 129/Sv mice with genetically diverse strains to generate p53+/− F1 hybrids. The results showed that genetic background had a profound impact on tumor latency after exposure to gamma radiation, while the tumor spectrum did not change. We further characterized the thymic lymphomas that arose in the p53+/− mice by genome-wide loss of heterozygosity (LOH) analyses and found that genetic background strongly influenced the frequency of LOH and the loss of which parental allele on different chromosomes. Further research is needed to identify which genetic variations control the LOH patterns in radiation-induced thymic lymphomas and to evaluate its relevance to human cancers. PMID:25932465

  10. Comparison of Measured Galactic Background Radiation at L-Band with Model

    NASA Technical Reports Server (NTRS)

    LeVine, David M.; Abraham, Saji; Kerr, Yann H.; Wilson, William J.; Skou, Niels; Sobjaerg, Sten

    2004-01-01

    Radiation from the celestial sky in the spectral window at 1.413 GHz is strong and an accurate accounting of this background radiation is needed for calibration and retrieval algorithms. Modern radio astronomy measurements in this window have been converted into a brightness temperature map of the celestial sky at L-band suitable for such applications. This paper presents a comparison of the background predicted by this map with the measurements of several modern L-band remote sensing radiometer Keywords-Galactic background, microwave radiometry; remote sensing;

  11. Experimental study of variations in background radiation and the effect on Nuclear Car Wash sensitivity

    SciTech Connect

    Church, J; Slaughter, D; Norman, E; Asztalos, S; Biltoft, P

    2007-02-07

    Error rates in a cargo screening system such as the Nuclear Car Wash [1-7] depend on the standard deviation of the background radiation count rate. Because the Nuclear Car Wash is an active interrogation technique, the radiation signal for fissile material must be detected above a background count rate consisting of cosmic, ambient, and neutron-activated radiations. It was suggested previously [1,6] that the Corresponding negative repercussions for the sensitivity of the system were shown. Therefore, to assure the most accurate estimation of the variation, experiments have been performed to quantify components of the actual variance in the background count rate, including variations in generator power, irradiation time, and container contents. The background variance is determined by these experiments to be a factor of 2 smaller than values assumed in previous analyses, resulting in substantially improved projections of system performance for the Nuclear Car Wash.

  12. Background radiation and childhood leukemia: A nationwide register-based case-control study.

    PubMed

    Nikkilä, Atte; Erme, Sini; Arvela, Hannu; Holmgren, Olli; Raitanen, Jani; Lohi, Olli; Auvinen, Anssi

    2016-11-01

    High doses of ionizing radiation are an established cause of childhood leukemia. However, substantial uncertainty remains about the effect of low doses of radiation, including background radiation and potential differences between genetic subgroups of leukemia have rarely been explored. We investigated the effect of the background gamma radiation on childhood leukemia using a nationwide register-based case-control study. For each of the 1,093 cases, three age- and gender matched controls were selected (N = 3,279). Conditional logistic regression analyses were adjusted for confounding by Down syndrome, birth weight (large for gestational age), and maternal smoking. Complete residential histories and previously collected survey data of the background gamma radiation in Finland were used to assess the exposure of the study subjects to indoor and outdoor gamma radiation. Overall, background gamma radiation showed a non-significant association with the OR of childhood leukemia (OR 1.01, 95% CI 0.97, 1.05 for 10 nSv/h increase in average equivalent dose rate to red bone marrow). In subgroup analyses, age group 2-<7 years displayed a larger effect (OR 1.27, 95% CI 1.01, 1.60 for 1 mSv increase in equivalent cumulative dose to red bone marrow). Suggestive difference in OR by genetic subtype was found. Our results provide further support to the notion that low doses of ionizing radiation increase the risk for childhood leukemia, particularly at age 2-<7 years. Our findings suggest a larger effect of radiation on leukemia with high hyperpdiploidy than other subgroups, but this result requires further confirmation.

  13. Background radiation and childhood leukemia: A nationwide register-based case-control study.

    PubMed

    Nikkilä, Atte; Erme, Sini; Arvela, Hannu; Holmgren, Olli; Raitanen, Jani; Lohi, Olli; Auvinen, Anssi

    2016-11-01

    High doses of ionizing radiation are an established cause of childhood leukemia. However, substantial uncertainty remains about the effect of low doses of radiation, including background radiation and potential differences between genetic subgroups of leukemia have rarely been explored. We investigated the effect of the background gamma radiation on childhood leukemia using a nationwide register-based case-control study. For each of the 1,093 cases, three age- and gender matched controls were selected (N = 3,279). Conditional logistic regression analyses were adjusted for confounding by Down syndrome, birth weight (large for gestational age), and maternal smoking. Complete residential histories and previously collected survey data of the background gamma radiation in Finland were used to assess the exposure of the study subjects to indoor and outdoor gamma radiation. Overall, background gamma radiation showed a non-significant association with the OR of childhood leukemia (OR 1.01, 95% CI 0.97, 1.05 for 10 nSv/h increase in average equivalent dose rate to red bone marrow). In subgroup analyses, age group 2-<7 years displayed a larger effect (OR 1.27, 95% CI 1.01, 1.60 for 1 mSv increase in equivalent cumulative dose to red bone marrow). Suggestive difference in OR by genetic subtype was found. Our results provide further support to the notion that low doses of ionizing radiation increase the risk for childhood leukemia, particularly at age 2-<7 years. Our findings suggest a larger effect of radiation on leukemia with high hyperpdiploidy than other subgroups, but this result requires further confirmation. PMID:27405274

  14. Level crossing analysis of cosmic microwave background radiation: a method for detecting cosmic strings

    SciTech Connect

    Movahed, M. Sadegh; Khosravi, Shahram E-mail: khosravi@ipm.ir

    2011-03-01

    In this paper we study the footprint of cosmic string as the topological defects in the very early universe on the cosmic microwave background radiation. We develop the method of level crossing analysis in the context of the well-known Kaiser-Stebbins phenomenon for exploring the signature of cosmic strings. We simulate a Gaussian map by using the best fit parameter given by WMAP-7 and then superimpose cosmic strings effects on it as an incoherent and active fluctuations. In order to investigate the capability of our method to detect the cosmic strings for the various values of tension, Gμ, a simulated pure Gaussian map is compared with that of including cosmic strings. Based on the level crossing analysis, the superimposed cosmic string with Gμ∼>4 × 10{sup −9} in the simulated map without instrumental noise and the resolution R = 1' could be detected. In the presence of anticipated instrumental noise the lower bound increases just up to Gμ∼>5.8 × 10{sup −9}.

  15. Use of superconducting bearings to measure the polarization of the cosmic microwave background radiation.

    SciTech Connect

    Hanany, S.; Matsumura, T.; Johnson, B.; Jones, T.; Hull, J. R.; Ma, K. B.

    2002-08-21

    Measurements of the polarization of the cosmic microwave background (CMB) radiation are expected to significantly increase our understanding of the early universe. We present a design for a CMB polarimeter in which a cryogenically cooled half wave plate rotates by means of a high-temperature superconducting (HTS) bearing. The design is optimized for implementation in MAXIPOL, a balloon-borne CMB polarimeter. A prototype bearing, consisting of commercially available ring-shaped permanent magnet and an array of YBCO bulk HTS material, has been constructed. We report on measurements of the coefficient of friction as a function of temperature between 15 and 80 K, of rotation frequency between 0.3 and 3.5 Hz, of levitation distance between 6 and 10 mm, and of ambient pressure between 1 and 10{sup -7} torr. The low rotational drag of the HTS bearing allows rotations for long periods of time with minimal input power and negligible wear and tear thus making this technology suitable for a future satellite mission.

  16. An Upper Limit on the Finescale Anisotropy of the Cosmic Background Radiation at 800-MICRONS

    NASA Astrophysics Data System (ADS)

    Church, S. E.; Lasenby, A. N.; Hills, R. E.

    1993-04-01

    In some models of the early Universe, radiation is reprocessed into the submillimetre and far-infrared by high-redshift dust, without violating COBE limits on the CBR spectrum, but producing secondary anisotropies which should be detectable with ground-based submillimetre telescopes. We describe an attempt to measure these anisotropies at 800 microns using the JCMT. A careful analysis to reduce position-dependent systematics was carried out and we show that, for this experiment, chopping the telescope beam in azimuth rather than RA produces lower systematics. Bayesian likelihood analysis is then used to set an upper limit on CBR fluctuations of {DELTA} T/T <~ 1.46 X 10^-3^ on a coherence scale of 17 arcsec. Data from a similar set of observations made by Kreysa & Chini in 1988 with the IBM 30-m telescope at 1300 microns are reanalysed in the same way to enable a comparison to be made. The results are used to set limits on the generation of cosmic backgrounds from primeval dust.

  17. Asymptotic freedom in the early big-bang and the isotropy of the cosmic microwave background

    NASA Technical Reports Server (NTRS)

    Stecker, F. W.

    1979-01-01

    The isotropy of the universal 3K background radiation is discussed and a superunified field theory incorporating gravity and possessing asymptotic freedom is suggested to provide a solution to the problem. Thermal equilibrium is established in this context through interactions occurring in a temporally indefinite preplanckian era.

  18. Asymptotic freedom in the early big bang and the isotropy of the cosmic microwave background

    NASA Technical Reports Server (NTRS)

    Stecker, F. W.

    1980-01-01

    It is suggested that a superunified field theory incorporating gravity and possessing asymptotic freedom could provide a solution to the problem of the isotropy of the universal 3 K background radiation. Thermal equilibrium could be established in this context through interactions occurring in a temporally indefinite pre-Planckian era.

  19. Cosmological implication of a new measurement of the submillimeter background radiation

    NASA Technical Reports Server (NTRS)

    Hayakawa, Satio; Matsumoto, Toshio; Matsuo, Hiroshi; Murakami, Hiroshi; Sato, Shinji

    1987-01-01

    A new submillimeter measurement of the cosmic background radiation (T. Matsumoto et al., 1988) reveals excess brightness between 1000 and 300 microns. The excess corresponds to about 10 percent of the undistorted blackbody radiation. The observed excess is consistent with thermal emission from dust with a relative density of 0.0001-0.00001, if the dust is heated at a redshift z of about 10-40.

  20. Radiation reaction from QED: Lightfront perturbation theory in a plane wave background

    NASA Astrophysics Data System (ADS)

    Ilderton, Anton; Torgrimsson, Greger

    2013-07-01

    We derive dynamical, real time radiation reaction effects from lightfront QED. Combining the Hamiltonian formalism with a plane wave background field, the calculation is performed in the Furry picture for which the background is treated exactly while interactions between quantum fields are treated in perturbation theory as normal. We work to a fixed order in perturbation theory, but no other approximation is made. The literature contains many proposals for the correct classical equation describing a radiating particle; we take the classical limit of our results and identify which equations are consistent with QED.

  1. High-latitude galactic emission and the search for anisotropies of the cosmic background radiation

    SciTech Connect

    Masi, S.; De Bernardis, P.; De Petris, M.; Epifani, M.; Gervasi, M. )

    1991-01-01

    The anisotropies of the diffuse radiation in the mm and sub-mm spectral region are studied. These are produced by insterstellar dust emission and radio continuum emission, and can contaminate the measurements of the cosmological background anisotropies. Two high Galactic latitude cosmological windows permit searches for cosmic background radiation anisotropies at a level of Delta-T/T of about 10 to the -6th, at angular scales between about 0.5 and 5 deg, in the spectral interval between 2 and 9/cm. 23 refs.

  2. Cosmic far-ultraviolet background radiation - Probe of a dense hot intergalactic medium

    NASA Technical Reports Server (NTRS)

    Sherman, R. D.; Silk, J.

    1979-01-01

    Line and continuum radiation fluxes have been computed for a wide range of enriched intergalactic medium (IGM) models. Observations of the diffuse extragalactic light at optical and far-ultraviolet wavelengths are found to provide a potentially important probe of a dense hot intergalactic medium. If the diffuse X-ray background is produced by this gas, the models constrain the cosmological density parameter (Omega) to be less than 0.4. The associated Compton distortions of the cosmic blackbody background radiation and the optical depths to distant quasars at X-ray wavelengths are also evaluated.

  3. Background radiation in two locations in Deaf Smith and Swisher Counties within the Palo Duro Basin

    SciTech Connect

    Not Available

    1984-10-01

    Data on external background radiation doses resulting from cosmic, terrestrial, and fallout sources and on concentrations of radioactivity in environmental media are presented and discussed. Doses to individuals located at the approximate centers of two locations in Texas, one in Deaf Smith County and the other in Swisher County, are given, as are the population doses to people residing within 50 miles of each of the approximate centers. No adjustments have been made for the effects of buildings on radiation doses - that is, the shielding from external radiation afforded by the buildings and radiation from building materials are not accounted for. Concentrations of radioactivity in air, water, and milk in the region are also given. Because of the lack of specific information on background radiation at the locations, the external-dose rates to people and the radioactivity levels in environmental media for the region have been taken from the literature. A background radiation survey will be conducted in the Palo Duro Basin to obtain additional data. 26 references, 3 figures, 15 tables.

  4. Propagation of Polarized Cosmic Microwave Background Radiation in an Anisotropic Magnetized Plasma

    SciTech Connect

    Moskaliuk, S. S.

    2010-01-01

    The polarization plane of the cosmic microwave background radiation (CMBR) can be rotated either in a space-time with metric of anisotropic type and in a magnetized plasma or in the presence of a quintessential background with pseudoscalar coupling to electromagnetism. A unified treatment of these three phenomena is presented for cold anisotropic plasma at the pre-recombination epoch. It is argued that the generalized expressions derived in the present study may be relevant for direct searches of a possible rotation of the cosmic microwave background polarization.

  5. The cosmic microwave background radiation temperature at a redshift of 2.34.

    PubMed

    Srianand, R; Petitjean, P; Ledoux, C

    The existence of the cosmic microwave background radiation is a fundamental prediction of hot Big Bang cosmology, and its temperature should increase with increasing redshift. At the present time (redshift z = 0), the temperature has been determined with high precision to be T(CMBR)(0) = 2.726 +/- 0.010 K. In principle, the background temperature can be determined using measurements of the relative populations of atomic fine-structure levels, which are excited by the background radiation. But all previous measurements have achieved only upper limits, thus still formally permitting the radiation temperature to be constant with increasing redshift. Here we report the detection of absorption lines from the first and second fine-structure levels of neutral carbon atoms in an isolated cloud of gas at z = 2.3371. We also detected absorption due to several rotational transitions of molecular hydrogen, and fine-structure lines of singly ionized carbon. These constraints enable us to determine that the background radiation was indeed warmer in the past: we find that T(CMBR)(z = 2.3371) is between 6.0 and 14 K. This is in accord with the temperature of 9.1 K predicted by hot Big Bang cosmology.

  6. Quantum Larmor Radiation from a Moving Charge in AN Electromagnetic Plane Wave Background

    NASA Astrophysics Data System (ADS)

    Nakamura, Gen; Yamamoto, Kazuhiro

    2012-09-01

    We extend our previous work [Phys. Rev. D83, 045030 (2011)], which investigated the first-order quantum effect in the Larmor radiation from a moving charge in a spatially homogeneous time-dependent electric field. Specifically, we investigate the quantum Larmor radiation from a moving charge in a monochromatic electromagnetic plane wave background based on the scalar quantum electrodynamics at the lowest order of the perturbation theory. Using the in-in formalism, we derive the theoretical formula of the total radiation energy from a charged particle in the initial states being at rest and being in a relativistic motion. Expanding the theoretical formula in terms of the Planck constant ℏ, we obtain the first-order quantum effect on the Larmor radiation. The quantum effect generally suppresses the total radiation energy compared with the prediction of the classical Larmor formula, which is a contrast to the previous work. The reason is explained by the fact that the radiation from a moving charge in a monochromatic electromagnetic plane wave is expressed in terms of the inelastic collisions between an electron and photons of the background electromagnetic waves.

  7. Investigation of background radiation levels and geologic unit profiles in Durango, Colorado

    SciTech Connect

    Triplett, G.H. ); Foutz, W.L.; Lesperance, L.R. )

    1989-11-01

    As part of the Uranium Mill Tailings Remedial Action (UMTRA) Project, Oak Ridge National Laboratory (ORNL) has performed radiological surveys on 435 vicinity properties (VPs) in the Durango area. This study was undertaken to establish the background radiation levels and geologic unit profiles in the Durango VP area. During the months of May through June, 1986, extensive radiometric measurements and surface soil samples were collected in the Durango VP area by personnel from ORNL's Grand Junction Office. A majority of the Durango VP surveys were conducted at sites underlain by Quaternary alluvium, older Quaternary gravels, and Cretaceous Lewis and Mancos shales. These four geologic units were selected to be evaluated. The data indicated no formation anomalies and established regional background radiation levels. Durango background radionuclide concentrations in surface soil were determined to be 20.3 {plus minus} 3.4 pCi/g for {sup 40}K, 1.6 {plus minus} 0.5 pCi/g for {sup 226}Ra, and 1.2 {plus minus} 0.3 pCi/g for {sup 232}Th. The Durango background gamma exposure rate was found to be 16.5 {plus minus} 1.3 {mu}R/h. Average gamma spectral count rate measurements for {sup 40}K, {sup 226}Ra and {sup 232}Th were determined to be 553, 150, and 98 counts per minute (cpm), respectively. Geologic unit profiles and Durango background radiation measurements are presented and compared with other areas. 19 refs., 15 figs., 5 tabs.

  8. Thyroid nodularity and chromosome aberrations among women in areas of high background radiation in China

    SciTech Connect

    Wang, Z.Y.; Boice, J.D. Jr.; Wei, L.X.; Beebe, G.W.; Zha, Y.R.; Kaplan, M.M.; Tao, Z.F.; Maxon, H.R. III; Zhang, S.Z.; Schneider, A.B. )

    1990-03-21

    Thyroid nodularity following continuous low-dose radiation exposure in China was determined in 1,001 women aged 50-65 years who resided in areas of high background radiation (330 mR/yr) their entire lives, and in 1,005 comparison subjects exposed to normal levels of radiation (114 mR/yr). Cumulative doses to the thyroid were estimated to be of the order of 14 cGy and 5 cGy, respectively. Personal interviews and physical examinations were conducted, and measurements were made of serum thyroid hormone levels, urinary iodine concentrations, and chromosome aberrations in circulating lymphocytes. For all nodular disease, the prevalences in the high background and control areas were 9.5% and 9.3%, respectively. For single nodules, the prevalences were 7.4% in the high background area and 6.6% in the control area (prevalence ratio = 1.13; 95% confidence interval = 0.82-1.55). There were no differences found in serum levels of thyroid hormones. Women in the high background region, however, had significantly lower concentrations of urinary iodine and significantly higher frequencies of stable and unstable chromosome aberrations. Increased intake of allium vegetables such as garlic and onions was associated with a decreased risk of nodular disease, which seems consistent with experimental studies suggesting that allium compounds can inhibit tumor growth and proliferation. The prevalence of mild diffuse goiter was higher in the high background radiation region, perhaps related to a low dietary intake of iodine. These data suggest that continuous exposure to low-level radiation throughout life is unlikely to appreciably increase the risk of thyroid cancer. However, such exposure may cause chromosomal damage.

  9. The 1999 Lauriston S. Taylor lecture--back to background: natural radiation and radioactivity exposed.

    PubMed

    Harley, N H

    2000-08-01

    I am profoundly grateful for being chosen as the twenty-third presenter of the Lauriston S. Taylor Lecture, and I share this honor with a list of distinguished scientists, including my husband, who pay tribute to the premier leader in radiation protection. In 1938, Laurie was working for the National Bureau of Standards and chaired the Advisory Committee on X-ray and Radium Protection, a group of 8 persons, who set the pace for all forthcoming radiation standards. NBS had, since 1913, been standardizing essentially all of the radium offered for sale in the U.S., and the problem arose to revise the handbook on proper conditions for handling radium based on the then current knowledge. This resulted in Handbook 23 (1938) superseding the 1934 work. At the time Laurie was a scientist working in the measurements side of radiation and though he contributed much to that field, his name is inseparably linked with guidance in radiation protection. Today we pay tribute for his leadership that he carried out with intelligence, grace, and personal warmth. My talk today deals mostly with measured data for naturally occurring internal radiation emitters and how these data can be used for predictive purposes in estimating the dose and risk from internal body contamination. This stresses the "and Measurements" part of the Council's title. The topic of this year's NCRP Annual Meeting is "Radiation Protection in Medicine: Contemporary Issues." I believe that physicians and State and Federal agencies will have to cope with complaints following various exposure situations resulting from the cleanup of background radionuclides during closure at nuclear facilities, military use of radioactivity, and occurrences of high natural background in some locations. They will find comfort in the knowledge that existing background radiation data can be the basis for predictions of realistic dose and risk in most situations.

  10. The 1999 Lauriston S. Taylor lecture--back to background: natural radiation and radioactivity exposed.

    PubMed

    Harley, N H

    2000-08-01

    I am profoundly grateful for being chosen as the twenty-third presenter of the Lauriston S. Taylor Lecture, and I share this honor with a list of distinguished scientists, including my husband, who pay tribute to the premier leader in radiation protection. In 1938, Laurie was working for the National Bureau of Standards and chaired the Advisory Committee on X-ray and Radium Protection, a group of 8 persons, who set the pace for all forthcoming radiation standards. NBS had, since 1913, been standardizing essentially all of the radium offered for sale in the U.S., and the problem arose to revise the handbook on proper conditions for handling radium based on the then current knowledge. This resulted in Handbook 23 (1938) superseding the 1934 work. At the time Laurie was a scientist working in the measurements side of radiation and though he contributed much to that field, his name is inseparably linked with guidance in radiation protection. Today we pay tribute for his leadership that he carried out with intelligence, grace, and personal warmth. My talk today deals mostly with measured data for naturally occurring internal radiation emitters and how these data can be used for predictive purposes in estimating the dose and risk from internal body contamination. This stresses the "and Measurements" part of the Council's title. The topic of this year's NCRP Annual Meeting is "Radiation Protection in Medicine: Contemporary Issues." I believe that physicians and State and Federal agencies will have to cope with complaints following various exposure situations resulting from the cleanup of background radionuclides during closure at nuclear facilities, military use of radioactivity, and occurrences of high natural background in some locations. They will find comfort in the knowledge that existing background radiation data can be the basis for predictions of realistic dose and risk in most situations. PMID:10910381

  11. Radiation detection and wireless networked early warning

    NASA Astrophysics Data System (ADS)

    Burns, David A.; Litz, Marc S.; Carroll, James J.; Katsis, Dimosthenis

    2012-06-01

    We have designed a compact, wireless, GPS-enabled array of inexpensive radiation sensors based on scintillation counting. Each sensor has a scintillator, photomultiplier tube, and pulse-counting circuit that includes a comparator, digital potentiometer and microcontroller. This design provides a high level of sensitivity and reliability. A 0.2 m2 PV panel powers each sensor providing a maintenance-free 24/7 energy source. The sensor can be mounted within a roadway light-post and monitor radiological activity along transport routes. Each sensor wirelessly transmits real-time data (as counts per second) up to 2 miles with a XBee radio module, and the data is received by a XBee receive-module on a computer. Data collection software logs the information from all sensors and provides real-time identification of radiation events. Measurements performed to-date demonstrate the ability of a sensor to detect a 20 μCi source at 3.5 meters when packaged with a PVT (plastic) scintillator, and 7 meters for a sensor with a CsI crystal (more expensive but ~5 times more sensitive). It is calculated that the sensor-architecture can detect sources moving as fast as 130 km/h based on the current data rate and statistical bounds of 3-sigma threshold detection. The sensor array is suitable for identifying and tracking a radiation threat from a dirty bomb along roadways.

  12. Probing reionization with the cross-power spectrum of 21 cm and near-infrared radiation backgrounds

    SciTech Connect

    Mao, Xiao-Chun

    2014-08-01

    The cross-correlation between the 21 cm emission from the high-redshift intergalactic medium and the near-infrared (NIR) background light from high-redshift galaxies promises to be a powerful probe of cosmic reionization. In this paper, we investigate the cross-power spectrum during the epoch of reionization. We employ an improved halo approach to derive the distribution of the density field and consider two stellar populations in the star formation model: metal-free stars and metal-poor stars. The reionization history is further generated to be consistent with the electron-scattering optical depth from cosmic microwave background measurements. Then, the intensity of the NIR background is estimated by collecting emission from stars in first-light galaxies. On large scales, we find that the 21 cm and NIR radiation backgrounds are positively correlated during the very early stages of reionization. However, these two radiation backgrounds quickly become anti-correlated as reionization proceeds. The maximum absolute value of the cross-power spectrum is |Δ{sub 21,NIR}{sup 2}|∼10{sup −4} mK nW m{sup –2} sr{sup –1}, reached at ℓ ∼ 1000 when the mean fraction of ionized hydrogen is x-bar{sub i}∼0.9. We find that Square Kilometer Array can measure the 21 cm-NIR cross-power spectrum in conjunction with mild extensions to the existing CIBER survey, provided that the integration time independently adds up to 1000 and 1 hr for 21 cm and NIR observations, and that the sky coverage fraction of the CIBER survey is extended from 4 × 10{sup –4} to 0.1. Measuring the cross-correlation signal as a function of redshift provides valuable information on reionization and helps confirm the origin of the 'missing' NIR background.

  13. Early Events in Ionic Liquid Radiation Chemistry

    SciTech Connect

    Wishart, J.F.; Cook, A.; Rimmer, R.D.; Gohdo, M.

    2010-09-14

    Ionic liquids are interesting and useful materials whose solvation time scales are up to thousands of times longer than in conventional solvents. The extended lifetimes of pre-solvated electrons and other energetic species in ionic liquids has profound consequences for the radiolytic product distributions and reactivity patterns. We use a newly developed, multiplexed variation of pulse-probe spectroscopy to measure the kinetics of the early dynamical and reactive events in ionic liquids.

  14. Impact of the Fukushima nuclear accident on background radiation doses measured by control dosimeters in Japan.

    PubMed

    Romanyukha, Alexander; King, David L; Kennemur, Lisa K

    2012-05-01

    After the 9.0 magnitude earthquake and subsequent massive tsunami on 11 March 2011 in Japan, several reactors at the Fukushima Daiichi Nuclear Power Plant suffered severe damage. There was immediate participation of U.S. Navy vessels and other United States Department of Defense (DoD) teams that were already in the area at the time of the disaster or arrived shortly thereafter. The correct determination of occupational dose equivalent requires estimation of the background dose component measured by control dosimeters, which is subsequently subtracted from the total dose equivalent measured by personal dosimeters. The purpose of the control dosimeters is to determine the amount of radiation dose equivalent that has accumulated on the dosimeter from background or other non-occupational sources while they are in transit or being stored. Given the release of radioactive material and potential exposure to radiation from the Fukushima Daiichi Nuclear Power Plant and the process by which the U.S. Navy calculates occupational exposure to ionizing radiation, analysis of pre- and post-event control dosimeters is warranted. Several hundred historical dose records from the Naval Dosimetry Center (NDC) database were analyzed and compared with the post-accident dose equivalent data of control dosimeters. As result, it was shown that the dose contribution of the radiation and released radiological materials from the Fukushima nuclear accident to background radiation doses is less than 0.375 μSv d for shallow and deep photon dose equivalent. There is no measurable effect on neutron background exposure. The latter has at least two important conclusions. First, the NDC can use doses measured by control dosimeters at issuing sites in Japan for determination of personnel dose equivalents; second, the dose data from control dosimeters prior to and after the Fukushima accident may be used to assist in dose reconstruction of non-radiological (non-badged) personnel at these locations.

  15. Auditory-neurophysiological responses to speech during early childhood: Effects of background noise.

    PubMed

    White-Schwoch, Travis; Davies, Evan C; Thompson, Elaine C; Woodruff Carr, Kali; Nicol, Trent; Bradlow, Ann R; Kraus, Nina

    2015-10-01

    Early childhood is a critical period of auditory learning, during which children are constantly mapping sounds to meaning. But this auditory learning rarely occurs in ideal listening conditions-children are forced to listen against a relentless din. This background noise degrades the neural coding of these critical sounds, in turn interfering with auditory learning. Despite the importance of robust and reliable auditory processing during early childhood, little is known about the neurophysiology underlying speech processing in children so young. To better understand the physiological constraints these adverse listening scenarios impose on speech sound coding during early childhood, auditory-neurophysiological responses were elicited to a consonant-vowel syllable in quiet and background noise in a cohort of typically-developing preschoolers (ages 3-5 yr). Overall, responses were degraded in noise: they were smaller, less stable across trials, slower, and there was poorer coding of spectral content and the temporal envelope. These effects were exacerbated in response to the consonant transition relative to the vowel, suggesting that the neural coding of spectrotemporally-dynamic speech features is more tenuous in noise than the coding of static features-even in children this young. Neural coding of speech temporal fine structure, however, was more resilient to the addition of background noise than coding of temporal envelope information. Taken together, these results demonstrate that noise places a neurophysiological constraint on speech processing during early childhood by causing a breakdown in neural processing of speech acoustics. These results may explain why some listeners have inordinate difficulties understanding speech in noise. Speech-elicited auditory-neurophysiological responses offer objective insight into listening skills during early childhood by reflecting the integrity of neural coding in quiet and noise; this paper documents typical response

  16. Auditory-neurophysiological responses to speech during early childhood: Effects of background noise

    PubMed Central

    White-Schwoch, Travis; Davies, Evan C.; Thompson, Elaine C.; Carr, Kali Woodruff; Nicol, Trent; Bradlow, Ann R.; Kraus, Nina

    2015-01-01

    Early childhood is a critical period of auditory learning, during which children are constantly mapping sounds to meaning. But learning rarely occurs under ideal listening conditions—children are forced to listen against a relentless din. This background noise degrades the neural coding of these critical sounds, in turn interfering with auditory learning. Despite the importance of robust and reliable auditory processing during early childhood, little is known about the neurophysiology underlying speech processing in children so young. To better understand the physiological constraints these adverse listening scenarios impose on speech sound coding during early childhood, auditory-neurophysiological responses were elicited to a consonant-vowel syllable in quiet and background noise in a cohort of typically-developing preschoolers (ages 3–5 yr). Overall, responses were degraded in noise: they were smaller, less stable across trials, slower, and there was poorer coding of spectral content and the temporal envelope. These effects were exacerbated in response to the consonant transition relative to the vowel, suggesting that the neural coding of spectrotemporally-dynamic speech features is more tenuous in noise than the coding of static features—even in children this young. Neural coding of speech temporal fine structure, however, was more resilient to the addition of background noise than coding of temporal envelope information. Taken together, these results demonstrate that noise places a neurophysiological constraint on speech processing during early childhood by causing a breakdown in neural processing of speech acoustics. These results may explain why some listeners have inordinate difficulties understanding speech in noise. Speech-elicited auditory-neurophysiological responses offer objective insight into listening skills during early childhood by reflecting the integrity of neural coding in quiet and noise; this paper documents typical response properties

  17. Enhanced polarization of the cosmic microwave background radiation from thermal gravitational waves.

    PubMed

    Bhattacharya, Kaushik; Mohanty, Subhendra; Nautiyal, Akhilesh

    2006-12-22

    If inflation was preceded by a radiation era, then at the time of inflation there will exist a decoupled thermal distribution of gravitons. Gravitational waves generated during inflation will be amplified by the process of stimulated emission into the existing thermal distribution of gravitons. Consequently, the usual zero temperature scale invariant tensor spectrum is modified by a temperature dependent factor. This thermal correction factor amplifies the B-mode polarization of the cosmic microwave background radiation by an order of magnitude at large angles, which may now be in the range of observability of the Wilkinson Microwave Anisotropy Probe.

  18. Background Ionizing Radiation and the Risk of Childhood Cancer: A Census-Based Nationwide Cohort Study

    PubMed Central

    Lupatsch, Judith E.; Zwahlen, Marcel; Röösli, Martin; Niggli, Felix; Grotzer, Michael A.; Rischewski, Johannes; Egger, Matthias; Kuehni, Claudia E.

    2015-01-01

    Background Exposure to medium or high doses of ionizing radiation is a known risk factor for cancer in children. The extent to which low-dose radiation from natural sources contributes to the risk of childhood cancer remains unclear. Objectives In a nationwide census-based cohort study, we investigated whether the incidence of childhood cancer was associated with background radiation from terrestrial gamma and cosmic rays. Methods Children < 16 years of age in the Swiss National Censuses in 1990 and 2000 were included. The follow-up period lasted until 2008, and incident cancer cases were identified from the Swiss Childhood Cancer Registry. A radiation model was used to predict dose rates from terrestrial and cosmic radiation at locations of residence. Cox regression models were used to assess associations between cancer risk and dose rates and cumulative dose since birth. Results Among 2,093,660 children included at census, 1,782 incident cases of cancer were identified including 530 with leukemia, 328 with lymphoma, and 423 with a tumor of the central nervous system (CNS). Hazard ratios for each millisievert increase in cumulative dose of external radiation were 1.03 (95% CI: 1.01, 1.05) for any cancer, 1.04 (95% CI: 1.00, 1.08) for leukemia, 1.01 (95% CI: 0.96, 1.05) for lymphoma, and 1.04 (95% CI: 1.00, 1.08) for CNS tumors. Adjustment for a range of potential confounders had little effect on the results. Conclusions Our study suggests that background radiation may contribute to the risk of cancer in children, including leukemia and CNS tumors. Citation Spycher BD, Lupatsch JE, Zwahlen M, Röösli M, Niggli F, Grotzer MA, Rischewski J, Egger M, Kuehni CE, for the Swiss Pediatric Oncology Group and the Swiss National Cohort. 2015. Background ionizing radiation and the risk of childhood cancer: a census-based nationwide cohort study. Environ Health Perspect 123:622–628; http://dx.doi.org/10.1289/ehp.1408548 PMID:25707026

  19. Probing the Light Speed Anisotropy with Respect to the Cosmic Microwave Background Radiation Dipole

    NASA Astrophysics Data System (ADS)

    Gurzadyan, V. G.; Bocquet, J.-P.; Kashin, A.; Margarian, A.; Bartalini, O.; Bellini, V.; Castoldi, M.; D'Angelo, A.; Didelez, J.-P.; di Salvo, R.; Fantini, A.; Gervino, G.; Ghio, F.; Girolami, B.; Giusa, A.; Guidal, M.; Hourany, E.; Knyazyan, S.; Kouznetsov, V.; Kunne, R.; Lapik, A.; Levi Sandri, P.; Lleres, A.; Mehrabyan, S.; Moricciani, D.; Nedorezov, V.; Perrin, C.; Rebreyend, D.; Russo, G.; Rudnev, N.; Schaerf, C.; Sperduto, M.-L.; Sutera, M.-C.; Turinge, A.

    We have studied the angular fluctuations in the speed of light with respect to the apex of the dipole of Cosmic Microwave Background (CMB) radiation using the experimental data obtained with GRAAL facility, located at the European Synchrotron Radiation Facility (ESRF) in Grenoble. The measurements were based on the stability of the Compton edge of laser photons scattered on the 6 GeV monochromatic electron beam. The results enable one to obtain a conservative constraint on the anisotropy in the light speed variations Δc(θ)/c<3×10-12, i.e. with higher precision than from previous experiments.

  20. A procedure for the extraction of airglow features in the presence of strong background radiation

    NASA Astrophysics Data System (ADS)

    Swift, W. R.; Torr, D. G.; Hamilton, C.; Dougani, H.; Torr, M. R.

    1990-09-01

    A technique is developed that can be used to derive the total intensity of band emissions from twilight airglow measurements when the basic spectral signature of the band to be considered is known. The method is designed to automatically extract total band or line intensities of a signal imbedded in background radiation several orders of magnitude greater in brightness. It is shown that the technique developed can reliably measure the intensity of both weak and strong band and line emissions in the presence of strong twilight background radiation. The method of extraction is shown as part of a general purpose spectral analysis program written in VAX FORTRAN. This extraction procedure has been used successfully on emissions of Fel, Ca(+), N2(+) (1N) (0-0) and (0-1), OH in the near UV. OI red (630nm) and green (558nm) lines in the visible, and the OH Meinel bands and O(+) (2P) 732 nm in the near IR.

  1. A shallow underground laboratory for low-background radiation measurements and materials development

    SciTech Connect

    Aalseth, C. E.; Bonicalzi, R. M.; Cantaloub, M. G.; Day, A. R.; Erikson, L. E.; Fast, J.; Forrester, J. B.; Fuller, E. S.; Glasgow, B. D.; Greenwood, L. R.; Hoppe, E. W.; Hossbach, T. W.; Hyronimus, B. J.; Keillor, M. E.; Mace, E. K.; McIntyre, J. I.; Merriman, J. H.; Myers, A. W.; Overman, C. T.; Overman, N. R.; and others

    2012-11-15

    Pacific Northwest National Laboratory recently commissioned a new shallow underground laboratory, located at a depth of approximately 30 meters-water-equivalent. This new addition to the small class of radiation measurement laboratories located at modest underground depths houses the latest generation of custom-made, high-efficiency, low-background gamma-ray spectrometers and gas proportional counters. This paper describes the unique capabilities present in the shallow underground laboratory; these include large-scale ultra-pure materials production and a suite of radiation detection systems. Reported data characterize the degree of background reduction achieved through a combination of underground location, graded shielding, and rejection of cosmic-ray events. We conclude by presenting measurement targets and future opportunities.

  2. A Shallow Underground Laboratory for Low-Background Radiation Measurements and Materials Development

    SciTech Connect

    Aalseth, Craig E.; Bonicalzi, Ricco; Cantaloub, Michael G.; Day, Anthony R.; Erikson, Luke E.; Fast, James E.; Forrester, Joel B.; Fuller, Erin S.; Glasgow, Brian D.; Greenwood, Lawrence R.; Hoppe, Eric W.; Hossbach, Todd W.; Hyronimus, Brian J.; Keillor, Martin E.; Mace, Emily K.; McIntyre, Justin I.; Merriman, Jason H.; Myers, Allan W.; Overman, Cory T.; Overman, Nicole R.; Panisko, Mark E.; Seifert, Allen; Warren, Glen A.; Runkle, Robert C.

    2012-11-08

    Abstract: Pacific Northwest National Laboratory recently commissioned a new shallow underground laboratory, located at a depth of approximately 30 meters water-equivalent. This new addition to the small class of radiation measurement laboratories located at modest underground depths worldwide houses the latest generation of custom-made, high-efficiency, low-background gamma-ray spectrometers and gas proportional counters. This manuscript describes the unique capabilities present in the shallow underground laboratory; these include large-scale ultra-pure materials production and a suite of radiation detection systems. Reported data characterize the degree of background reduction achieved through a combination of underground location, graded shielding, and rejection of cosmic-ray events. We conclude by presenting measurement targets and future opportunities.

  3. The space microwave interferometer and the search for cosmic background gravitational wave radiation

    NASA Technical Reports Server (NTRS)

    Anderson, Allen Joel

    1989-01-01

    Present and planned investigations which use interplanetary spacecraft for gravitational wave searches are severely limited in their detection capability. This limitation has to do both with the Earth-based tracking procedures used and with the configuration of the experiments themselves. It is suggested that a much improved experiment can now be made using a multiarm interferometer designed with current operating elements. An important source of gravitational wave radiation, the cosmic background, may well be within reach of detection with these procedures. It is proposed to make a number of experimental steps that can now be carried out using TDRSS spacecraft and would conclude in the establishment of an operating multiarm microwave interferometer. This interferometer is projected to have a sensitivity to cosmic background gravitational wave radiation with an energy of less than 10(exp -4) cosmic closure density and to periodic waves generating spatial strain approaching 10(exp -19) in the range 0.1 to 0.001 Hz.

  4. Impact of dark energy-dark matter interaction on Cosmic Microwave Background Radiation

    NASA Astrophysics Data System (ADS)

    Verma, Murli

    It has been shown that an arc-like pattern found on the Cosmic Microwave Background Radiation (CMBR) may result from the decay of dark matter particles initiating near particle horizon in the Q-phase of the interacting cosmological constant (ICC) model. In the present work, an investigation is made into how the corresponding decay of such dark matter particles might influence these signatures, in view of the recent data from PLANCK on CMBR and the diffuse glow of the anomalous microwave radiation. We also discuss the constraints on such decay imposed by the interaction of the cosmological constant with the background. These predictions made in the ICC model can be verified in the concordance space of multiple observations.

  5. The effects of residence duration in high background radiation areas on immune surveillance

    PubMed Central

    Borzoueisileh, Sajad; Monfared, Ali Shabestani; Abediankenari, Saeid; Mostafazadeh, Amrollah; Khosravifarsani, Meysam

    2013-01-01

    Purpose: The effective dose received by humans from natural sources is about 2.4 mSv y-1, but this is 10.2 mSv y-1 for inhabitants of Ramsar, a city in northern Iran. Carcinogenesis is one of the most studied effects of radiation, especially in high doses. Nonetheless carcinogenesis of low doses is uncertain. A recent epidemiological study in high background radiation areas of Ramsar showed that the cancer incidence in this era is lower than neighbors. The reason of this different behavior is under study yet. NK cells, helper, and Cytotoxic T cells are most important components of the tumor immune surveillance. The counts and activities of these cells and also leukocytes, lymphocyte, neutrophil cells, and other important parameters were studied in the residents of Ramsar with different duration of exposure to chronic low dose radiation. Materials and Methods: Fifty residents of high background radiation areas, who were between 25 and 35 years and fully healthy, were selected randomly and their consent was obtained. Then, 2 cc fresh peripheral bloods were taken in sterile conditions. Complete blood cell counts were performed by an automatic hematology analyzer and CD4+, CD8+, NK, and CD107a+ cell counts were determined by monoclonal antibodies and flowcytometry. CD4+ and CD8+ percentages and the CD4/CD8 ratio were determined and the data were analyzed using SPSS 16. Results: The percentages of CD4+ cells increase, but the counts of CD107a+ cells decline in higher exposure durations. The other parameters did not have significant regression with exposure duration. Conclusions: These confirm that living in high background radiation areas may induce changes in the immune system gradually and address more investigations. PMID:23633866

  6. Possibilities of background-radiation-level reduction in proton-therapy rooms

    NASA Astrophysics Data System (ADS)

    Ivanov, N. A.; Lebedeva, Zh. S.

    2014-08-01

    The system of proton-beam formation for proton ophthalmology has been numerically simulated using the Geant4 program package. Data on the efficiency of narrow- ("pencil") and wide proton-beam transport are presented. It is established that the use of a wide beam transport is advantageous, since it makes a significant decrease in the background-radiation level in a proton-therapy room possible and simplifies the beam-formation system.

  7. Low Frequency Measurement of the Spectrum of the Cosmic Background Radiation

    DOE R&D Accomplishments Database

    Smoot, G. F.; De Amici, G.; Friedman, S. D.; Witebsky, C.; Mandolesi, N.; Partridge, R. B.; Sironi, G.; Danese, L.; De Zotti, G.

    1983-06-01

    We have made measurements of the cosmic background radiation spectrum at 5 wavelengths (0.33, 0.9, 3, 6.3, and 12 cm) using radiometers with wavelength-scaled corrugated horn antennas having very low sidelobes. A single large-mouth (0.7 m diameter) liquid-helium-cooled absolute reference load was used for all five radiometers. The results of the observations are consistent with previous measurements and represent a significant improvement in accuracy.

  8. Application of background-oriented schlieren method to the visualization inhomogenities of liquid during exposure to laser radiation

    NASA Astrophysics Data System (ADS)

    Popova, E. V.; Skornyakova, N. M.; Tolkachev, A. V.

    2005-02-01

    The application of Background Oriented Schlieren method to the visualization of the laser radiation heating of the absorbing liquid is investigated. The results of the visualization with the different background screens are presented. The influence of the background screen on the resolution is shown. The optimal correlation processing parameters for this background screen are chosen.

  9. The Effects of Nearby Clusters of Galaxies on the Microwave Background Radiation

    NASA Technical Reports Server (NTRS)

    Birkinshaw, M.

    1999-01-01

    This project proposed to use the COBE (Cosmic Background Explorer) DMR sky-maps to measure the anisotropies introduced into the microwave background radiation by the Sunyaev-Zel'dovich and Rees-Sciama effects of nearby clusters and superclusters of galaxies. We intended to seek these effects by making maps of the best-fit anisotropies on particular angular scales and comparing the apparent anisotropies near target clusters and superclusters with the statistical noise and sky variance. The locations of the clusters and superclusters were to be found using HEAO-1 (High Energy Astronomy Observatory) A2 and Einstein X-ray maps. Checks against biases were to be made using radio and X-ray sky-maps as guides to the properties of the clusters and superclusters. Any signals detected would have implications for the gas properties and baryonic masses of clusters and superclusters. The scientific background, project activities and references to published papers are included.

  10. Radiation Plus Chemotherapy in Early-Stage Hodgkin Lymphoma

    Cancer.gov

    Adding radiation therapy to chemotherapy may improve outcomes in patients with early-stage Hodgkin lymphoma, according to a paper published in the Cochrane Database of Systematic Reviews in February 2011, but the long-term effects of this regimen are not

  11. On the population of primordial star clusters in the presence of ultraviolet background radiation

    NASA Astrophysics Data System (ADS)

    MacIntyre, Michael A.; Santoro, Fernando; Thomas, Peter A.

    2006-05-01

    We use the algorithm of Cole et al. to generate merger trees for the first star clusters in a Λ cold dark matter (ΛCDM) cosmology under an isotropic ultraviolet background radiation field, parametrized by J21. We have investigated the problem in two ways: a global radiation background and local radiative feedback surrounding the first star clusters. Cooling in the first haloes at high redshift is dominated by molecular hydrogen, H2- we call these Generation 1 objects. At lower redshift and higher virial temperature, Tvir>~ 104 K, electron cooling dominates - we call these Generation 2. Radiation fields act to photodissociate H2, but also generate free electrons that can help to catalyze its production. At modest radiation levels, J21/(1 +z)3~ 10-12-10-7, the nett effect is to enhance the formation of Generation 1 star clusters. At higher fluxes, the heating from photoionization dominates and halts their production. With a realistic build-up of flux over time, the period of enhanced H2 cooling is so fleeting as to be barely discernable and the nett effect is to move primordial star cluster formation towards Generation 2 objects at lower redshift. A similar effect is seen with local feedback. Provided that enough photons are produced to maintain ionization of their host halo, they will suppress the cooling in Generation 1 haloes and boost the numbers of primordial star clusters in Generation 2 haloes. Significant suppression of Generation 1 haloes occurs for specific photon fluxes in excess of about 1043phs-1M-1solar.

  12. Radionuclides and Radiation Indices of High Background Radiation Area in Chavara-Neendakara Placer Deposits (Kerala, India)

    PubMed Central

    Derin, Mary Thomas; Vijayagopal, Perumal; Venkatraman, Balasubramaniam; Chaubey, Ramesh Chandra; Gopinathan, Anilkumar

    2012-01-01

    The present paper describes a detailed study on the distribution of radionuclides along Chavara – Neendakara placer deposit, a high background radiation area (HBRA) along the Southwest coast of India (Kerala). Judged from our studies using HPGe gamma spectrometric detector, it becomes evident that Uranium (238U), Thorium (232Th) and Potassium (40K) are the major sources for radioactivity prevailing in the area. Our statistical analyses reveal the existence of a high positive correlation between 238U and 232Th, implicating that the levels of these elements are interdependent. Our SEM-EDAX analyses reveal that titanium (Ti) and zircon (Zr) are the major trace elements in the sand samples, followed by aluminum, copper, iron, ruthenium, magnesium, calcium, sulphur and lead. This is first of its kind report on the radiation hazard indices on this placer deposit. The average absorbed dose rates (9795 nGy h−1) computed from the present study is comparable with the top-ranking HBRAs in the world, thus offering the Chavara-Neendakara placer the second position, after Brazil; pertinently, this value is much higher than the World average. The perceptibly high absorbed gamma dose rates, entrained with the high annual external effective dose rates (AEED) and average annual gonadal dose equivalent (AGDE) values existing in this HBRA, encourage us to suggest for a candid assessment of the impact of the background radiation, if any, on the organisms that inhabit along this placer deposit. Future research could effectively address the issue of the possible impact of natural radiation on the biota inhabiting this HBRA. PMID:23185629

  13. New clade of enigmatic early archosaurs yields insights into early pseudosuchian phylogeny and the biogeography of the archosaur radiation

    PubMed Central

    2014-01-01

    Background The origin and early radiation of archosaurs and closely related taxa (Archosauriformes) during the Triassic was a critical event in the evolutionary history of tetrapods. This radiation led to the dinosaur-dominated ecosystems of the Jurassic and Cretaceous, and the high present-day archosaur diversity that includes around 10,000 bird and crocodylian species. The timing and dynamics of this evolutionary radiation are currently obscured by the poorly constrained phylogenetic positions of several key early archosauriform taxa, including several species from the Middle Triassic of Argentina (Gracilisuchus stipanicicorum) and China (Turfanosuchus dabanensis, Yonghesuchus sangbiensis). These species act as unstable ‘wildcards’ in morphological phylogenetic analyses, reducing phylogenetic resolution. Results We present new anatomical data for the type specimens of G. stipanicicorum, T. dabanensis, and Y. sangbiensis, and carry out a new morphological phylogenetic analysis of early archosaur relationships. Our results indicate that these three previously enigmatic taxa form a well-supported clade of Middle Triassic archosaurs that we refer to as Gracilisuchidae. Gracilisuchidae is placed basally within Suchia, among the pseudosuchian (crocodile-line) archosaurs. The approximately contemporaneous and morphologically similar G. stipanicicorum and Y. sangbiensis may be sister taxa within Gracilisuchidae. Conclusions Our results provide increased resolution of the previously poorly constrained relationships of early archosaurs, with increased levels of phylogenetic support for several key early pseudosuchian clades. Moreover, they falsify previous hypotheses suggesting that T. dabanensis and Y. sangbiensis are not members of the archosaur crown group. The recognition of Gracilisuchidae provides further support for a rapid phylogenetic diversification of crown archosaurs by the Middle Triassic. The disjunct distribution of the gracilisuchid clade in China and

  14. Levels of thoron and progeny in high background radiation area of southeastern coast of Odisha, India.

    PubMed

    Ramola, R C; Gusain, G S; Rautela, B S; Sagar, D V; Prasad, G; Shahoo, S K; Ishikawa, T; Omori, Y; Janik, M; Sorimachi, A; Tokonami, S

    2012-11-01

    Exposure to radon, (222)Rn, is assumed to be the most significant source of natural radiation to human beings in most cases. It is thought that radon and its progeny are major factors that cause cancer. The presence of thoron, (220)Rn, was often neglected because it was considered that the quantity of thoron in the environment is less than that of radon. However, recent studies have shown that a high thoron concentration was found in some regions and the exposure to (220)Rn and its progeny can equal or several time exceed that of (220)Rn and its progeny. The results of thoron and its progeny measurements in the houses of high background radiation area (HBRA) of the southeastern coast of Odisha, India presented here. This area is one of the high background radiation areas in India with a large deposit of monazite sand which is the probable source of thoron. Both active and passive methods were employed for the measurement of thoron and its progeny in cement, brick and mud houses in the study area. Thoron concentration was measured using RAD-7 and Raduet. A CR-39 track detector was employed for the measurement of environmental thoron progeny, both in active and passive modes. Thoron and its progeny concentrations were found to be comparatively high in the area. A comparison between the results obtained with various techniques is presented in this paper.

  15. Early-matter-like dark energy and the cosmic microwave background

    SciTech Connect

    Aurich, R.; Lustig, S. E-mail: sven.lustig@uni-ulm.de

    2016-01-01

    Early-matter-like dark energy is defined as a dark energy component whose equation of state approaches that of cold dark matter (CDM) at early times. Such a component is an ingredient of unified dark matter (UDM) models, which unify the cold dark matter and the cosmological constant of the ΛCDM concordance model into a single dark fluid. Power series expansions in conformal time of the perturbations of the various components for a model with early-matter-like dark energy are provided. They allow the calculation of the cosmic microwave background (CMB) anisotropy from the primordial initial values of the perturbations. For a phenomenological UDM model, which agrees with the observations of the local Universe, the CMB anisotropy is computed and compared with the CMB data. It is found that a match to the CMB observations is possible if the so-called effective velocity of sound c{sub eff} of the early-matter-like dark energy component is very close to zero. The modifications on the CMB temperature and polarization power spectra caused by varying the effective velocity of sound are studied.

  16. Short-lived variations in the background gamma-radiation dose.

    PubMed

    Burnett, J L; Croudace, I W; Warwick, P E

    2010-09-01

    Sudden increases in the background gamma-radiation dose may occur due to the removal of (222)Rn and (220)Rn progeny from the atmosphere by wet deposition mechanisms. This contribution has been measured using a Geiger-Muller detector at the Atomic Weapons Establishment (Aldermaston, UK) during July 2005-April 2006. The results are approximated by a log-normal distribution and there were nine separate occurrences of the gamma-radiation dose exceeding 125% of the geometric mean value. The increases were associated with periods of heavy rainfall, although no correlation was evident between the dose rate and the amount of rainfall, as increased rainfall dilutes the activity further rather than increasing its atmospheric removal. The events were preceded by periods of fine weather and atmospheric stability that allow for the build-up of (222)Rn and (220)Rn progeny. Similar increases in gamma-radiation dose have been measured at a nearby monitoring station situated approximately 11 miles from Aldermaston. Increases in gamma-radiation dose during heavy rainfall have also been observed throughout the UK, that followed the trajectory of an air mass. All events decreased to typical values within 1-2 h as the water permeated into the ground below and the radioactivity decayed away.

  17. Short-lived variations in the background gamma-radiation dose.

    PubMed

    Burnett, J L; Croudace, I W; Warwick, P E

    2010-09-01

    Sudden increases in the background gamma-radiation dose may occur due to the removal of (222)Rn and (220)Rn progeny from the atmosphere by wet deposition mechanisms. This contribution has been measured using a Geiger-Muller detector at the Atomic Weapons Establishment (Aldermaston, UK) during July 2005-April 2006. The results are approximated by a log-normal distribution and there were nine separate occurrences of the gamma-radiation dose exceeding 125% of the geometric mean value. The increases were associated with periods of heavy rainfall, although no correlation was evident between the dose rate and the amount of rainfall, as increased rainfall dilutes the activity further rather than increasing its atmospheric removal. The events were preceded by periods of fine weather and atmospheric stability that allow for the build-up of (222)Rn and (220)Rn progeny. Similar increases in gamma-radiation dose have been measured at a nearby monitoring station situated approximately 11 miles from Aldermaston. Increases in gamma-radiation dose during heavy rainfall have also been observed throughout the UK, that followed the trajectory of an air mass. All events decreased to typical values within 1-2 h as the water permeated into the ground below and the radioactivity decayed away. PMID:20826890

  18. Public exposure due to external gamma background radiation in boundary areas of Iran.

    PubMed

    Pooya, S M Hosseini; Dashtipour, M R; Enferadi, A; Orouji, T

    2015-09-01

    A monitoring program in boundary areas of a country is an appropriate way to indicate the level of public exposure. In this research, gamma background radiation was measured using TL dosimeters at 12 boundary areas as well as in the capital city of Iran during the period 2010 to 2011. The measurements were carried out in semi-annual time intervals from January to June and July to December in each year. The maximum average dose equivalent value measured was approximately 70 μSv/month for Tehran city. Also, the average dose values obtained were less than 40 μSv/month for all the cities located at the sea level except that of high level natural radiation area of Ramsar, and more than 55 μSv/month for the higher elevation cities. The public exposure due to ambient gamma dose equivalent in Iran is within the levels reported by UNSCEAR.

  19. Coherent dynamics of Rydberg atoms in cosmic-microwave-background radiation

    NASA Astrophysics Data System (ADS)

    Tscherbul, Timur V.; Brumer, Paul

    2014-01-01

    Rydberg atoms excited by cold blackbody radiation are shown to display long-lived quantum coherences on time scales of tens of picoseconds. By solving non-Markovian equations of motion with no free parameters we obtain the time evolution of the density matrix and demonstrate that the blackbody-induced temporal coherences manifest as slowly decaying (100 ps) quantum beats in time-resolved fluorescence. An analytic model shows the dependence of the coherent dynamics on the energy splitting between atomic eigenstates, transition dipole moments, and coherence time of the radiation. Experimental detection of the fluorescence signal from a trapped ensemble of 108 Rydberg atoms is discussed, but shown to be technically challenging at present, requiring cosmic-microwave-background amplification somewhat beyond current practice.

  20. A Question of Quality: Do Children from Disadvantaged Backgrounds Receive Lower Quality Early Childhood Education and Care?

    ERIC Educational Resources Information Center

    Gambaro, Ludovica; Stewart, Kitty; Waldfogel, Jane

    2015-01-01

    This paper examines how the quality of early childhood education and care accessed by 3- and 4-year-olds in England varies by children's background. Focusing on the free entitlement to early education, the analysis combines information from three administrative datasets for 2010-2011, the Early Years Census, the Schools Census and the Ofsted…

  1. Second dip as a signature of ultrahigh energy proton interactions with cosmic microwave background radiation.

    PubMed

    Berezinsky, V; Gazizov, A; Kachelrieb, M

    2006-12-01

    We discuss as a new signature for the interaction of extragalactic ultrahigh energy protons with cosmic microwave background radiation a spectral feature located at E= 6.3 x 10(19) eV in the form of a narrow and shallow dip. It is produced by the interference of e+e(-)-pair and pion production. We show that this dip and, in particular, its position are almost model-independent. Its observation by future ultrahigh energy cosmic ray detectors may give the conclusive confirmation that an observed steepening of the spectrum is caused by the Greisen-Zatsepin-Kuzmin effect.

  2. New 33 GHz Measurements of the Cosmic Background RadiationIntensity

    SciTech Connect

    De Amici, G.; Smoot, G.; Friedman, S.G.; Witebsky, C.

    1985-03-01

    New measurements have been made of the intensity of the cosmic background radiation (CBR) at 33 GHz (0.91 cm). The experiment was part of a larger effort to measure the spectrum of the CBR between 2.5 and 90 GHz (12 and 0.33 cm). Details are given of the experimental equipment and measurement procedures. The results of measurements made in 1982 and 1983 are presented and discussed in relation to preliminary results from the other radiometers. The measured value, T{sub CBR} = (2.81 {+-} 0.12) K, is in very good agreement both with those previously published and those reported by our collaborators.

  3. 3 mm Anisotropy Measurement: On the Quadrupole Component in theCosmic Background Radiation

    SciTech Connect

    Lubin, Philip M.; Epstein, Gerald L.; Smoot, George F.

    1982-11-01

    We have mapped the large-scale anisotropy in the cosmic background radiation at 3 mm wavelength using a liquid-helium-cooled balloon-borne radiometer sensitive enough to detect the dipole in one gondola rotation (1 minute). Statistical errors on the dipole and quadrupole components are below 0.1 mK with less than 0.1 m K galactic contribution. We find a dipole consistent with previous measurements but disagree with recent quadrupole reports. The measurement is also useful in searching for spectral distortions.

  4. Biaxial lidar efficiency rising based on improving of spatial selectivity and stability against background radiation

    SciTech Connect

    Agishev, R.R.; Bajazitov, R.A.; Galeyev, M.M.

    1996-12-31

    A criterion of spatial-angular efficiency (SAE) of remote electro-optical systems for atmosphere monitoring is formulated. The dependencies of the SAE from normalized range and minimal operating range for different optical receiving schemes of ground-based biaxial lidar are analyzed. It is shown that low SAE of traditional VIS and NIR systems are a main cause of a low signal-to-background-noise ratio at the photodetector input, the considerable measurements errors. and the following low accuracy of atmospheric optical parameters reconstruction. The most effective protection against sky background radiation in such systems consists in forming an angular field according to the introduced SAE criterion. Some approaches to achieve high value of the SAE-parameter for receiving system optimization are discussed.

  5. Apparatus having reduced background for measuring radiation activity in aerosol particles

    DOEpatents

    Rodgers, John C.; McFarland, Andrew R.; Oritz, Carlos A.; Marlow, William H.

    1992-01-01

    Apparatus having reduced background for measuring radiation activity in aerosol particles. A continuous air monitoring sampler is described for use in detecting the presence of alpha-emitting aerosol particles. An inlet fractionating screen has been demonstrated to remove about 95% of freshly formed radon progeny from the aerosol sample, and approximately 33% of partially aged progeny. Addition of an electrical condenser and a modified dichotomous virtual impactor are expected to produce considerable improvement in these numbers, the goal being to enrich the transuranic (TRU) fraction of the aerosols. This offers the possibility of improving the signal-to-noise ratio for the detected alpha-particle energy spectrum in the region of interest for detecting TRU materials associated with aerosols, thereby enhancing the performance of background-compensation algorithms for improving the quality of alarm signals intended to warn personnel of potentially harmful quantities of TRU materials in the ambient air.

  6. Looking for early black holes signatures in the anisotropies of Cosmic backgrounds

    NASA Astrophysics Data System (ADS)

    Cappelluti, Nico

    2016-04-01

    We currently do not know how Super Massive Black Holes are seeded and grow to form the observed massive QSO at z~7. This is puzzling, because at that redshift the Universe was still too young to allow the growth of such massive black holes from stellar remnant black hole seeds. Theoretical models, taking into account the paucity of metals in the early Universe, explain this by invoking the formation of massive black holes seeds at z>10 as Direct Collapse Black holes of remnants of dead POPIII stars. As of today we cannot claim any detection of any high-z (z>7) black hole in their early stage of life. However, our recent measures of the arcminute scale joint fluctuations of the Cosmic X-ray Background and the Cosmic Infrared Background by Chandra and Spitzer can be explained by a population of highly absorbed z>10 Direct Collapse Black Holes.I will review the recent discoveries obtained with different instruments and by different teams and critically discuss these findings and the interpretations.

  7. Radiation pneumonitis: a complication resulting from combined radiation and chemotherapy for early breast cancer

    SciTech Connect

    Gez, E.; Sulkes, A.; Isacson, R.; Catane, R.; Weshler, Z.

    1985-10-01

    Described is a patient with early breast carcinoma who developed clinical radiation pneumonitis during primary radiation therapy and concomitant chemotherapy that included prednisone. This syndrome developed three days following abrupt steroid withdrawal. Retrieval of steroids brought complete resolution of the clinical and radiological findings. Although this syndrome is rare, it is recommended that steroid therapy in a patient previously irradiated to the chest be avoided.

  8. The effects of early postoperative radiation on vascularized bone grafts

    SciTech Connect

    Evans, H.B.; Brown, S.; Hurst, L.N. )

    1991-06-01

    The effects of early postoperative radiation were assessed in free nonvascularized and free vascularized rib grafts in the canine model. The mandibles of one-half of the dogs were exposed to a cobalt 60 radiation dose of 4080 cGy over a 4-week period, starting 2 weeks postoperatively. The patency of vascularized grafts was confirmed with bone scintigraphy. Histological studies, including ultraviolet microscopy with trifluorochrome labeling, and histomorphometric analyses were performed. Osteocytes persist within the cortex of the vascularized nonradiated grafts to a much greater extent than in nonvascularized, nonradiated grafts. Cortical osteocytes do not persist in either vascularized or nonvascularized grafts subjected to radiation. New bone formation is significantly retarded in radiated grafts compared with nonradiated grafts. Periosteum and endosteum remained viable in the radiated vascularized grafts, producing both bone union and increased bone turnover, neither of which were evident to any significant extent in nonvascularized grafts. Bone union was achieved in vascularized and non-vascularized nonradiated bone. In the radiated group of dogs, union was only seen in the vascularized bone grafts.

  9. Cosmic background radiation anisotropy at degree angular scales - Further results from the South Pole

    NASA Technical Reports Server (NTRS)

    Schuster, Jeffrey; Gaier, Todd; Gundersen, Joshua; Meinhold, Peter; Koch, Timothy; Seiffert, Michael; Wuensche, Carlos A.; Lubin, Philip

    1993-01-01

    We report further results from the University of California at Santa Barbara program to measure anisotropy in the cosmic background radiation at angular scales near 1 deg, an angular range corresponding to the largest scales where structure is observed. A 30 GHz high electron mobility transistor amplifier-based detector was coupled to the Advanced Cosmic Microwave Explorer, a 1 m off-axis Gregorian telescope. We present data that represent 64 of the total of 500 hr acquired with this system during the 1990-1991 season. The data have a statistical error of 13.5/micro-K/pixel. These are the smallest error bars of any data set of this type published to date. The data contain a significant signal with a maximum likelihood Delta T/T roughly 1 x 10 exp -5. The spectrum of the signal seen in slightly less than 2 sigma away from the thermal spectrum expected of primordial fluctuations in the cosmic background radiation. If the source of the fluctuations is primordial, then the data are consistent with cold dark matter scenarios when normalized to the large-scale anisotropy observed by COBE, while if the origin of the signal is foreground emission or another form of contaminant then the data are marginally inconsistent with standard cold dark matter models. In either case, the data are sufficiently sensitive to provide a crucial test of many models.

  10. Interstellar cyanogen and the temperature of the cosmic microwave background radiation

    NASA Technical Reports Server (NTRS)

    Roth, Katherine C.; Meyer, David M.; Hawkins, Isabel

    1993-01-01

    We present the results of a recently completed effort to determine the amount of CN rotational excitation in five diffuse interstellar clouds for the purpose of accurately measuring the temperature of the cosmic microwave background radiation (CMBR). In addition, we report a new detection of emission from the strongest hyperfine component of the 2.64 mm CN rotational transition (N = 1-0) in the direction toward HD 21483. We have used this result in combination with existing emission measurements toward our other stars to correct for local excitation effects within diffuse clouds which raise the measured CN rotational temperature above that of the CMBR. After making this correction, we find a weighted mean value of T(CMBR) = 2.729 (+0.023, -0.031) K. This temperature is in excellent agreement with the new COBE measurement of 2.726 +/- 0.010 K (Mather et al., 1993). Our result, which samples the CMBR far from the near-Earth environment, attests to the accuracy of the COBE measurement and reaffirms the cosmic nature of this background radiation. From the observed agreement between our CMBR temperature and the COBE result, we conclude that corrections for local CN excitation based on millimeter emission measurements provide an accurate adjustment to the measured rotational excitation.

  11. A method of reducing background radiance for emissivity-compensated radiation thermometry of silicon wafers.

    PubMed

    Iuchi, T; Toyoda, Y; Seo, T

    2013-02-01

    We studied the spectral and directional emissivities of silicon wafers using an optical polarization technique. Based on simulation and experimental results, we developed two radiation thermometry methods for silicon wafers: one is based on the polarized emissivity-invariant condition and the other is based on the relationship between the ratio of the p- and s-polarized radiance and the polarized emissivity. These methods can be performed at temperatures above 600 °C and over a wide wavelength range (0.9-4.8 μm), irrespective of the dielectric film thickness and the substrate resistivity, which depends on the dopant concentration. The temperature measurements were estimated to have expanded uncertainties (k = 2) of less than 5 °C. With a view to practically applying these methods, we investigated a method to reduce the intense background radiance produced by high-intensity heating lamps. We found that the background radiance can be greatly reduced by using a radiometer that is sensitive to wavelengths of 4.5 or 4.8 μm and suitable geometrical arrangements of a quartz plate. This opens up the possibility of using the two proposed radiation thermometry methods in practical applications.

  12. Large-Angular-Scale Anisotropy in the Cosmic BackgroundRadiation

    SciTech Connect

    Gorenstein, M.V.; Smoot, G.F.

    1980-05-01

    We report the results of an extended series of airborne measurements of large-angular-scale anisotropy in the 3 K cosmic background radiation. Observations were carried out with a dual-antenna microwave radiometer operating at 33 GHz (0.89 cm wavelength) flown on board a U-2 aircraft to 20 km altitude. In eleven flights, between December 1976 and May 1978, the radiometer measured differential intensity between pairs of directions distributed over most of the northern hemisphere with an rms sensitivity of 47 mK Hz{sup -1/2}. The measurements show clear evidence of anisotropy that is readily interpreted as due to the solar motion relative to the sources of the radiation. The anisotropy is well fit by a first order spherical harmonic of amplitude 360 {+-} 50km sec{sup -1} toward the direction 11.2 {+-} 0.5 hours of right ascension and 19 {+-} 8 degrees declination. A simultaneous fit to a combined hypothesis of dipole and quadrupole angular distributions places a 1 mK limit on the amplitude of most components of quadrupole anisotropy with 90% confidence. Additional analysis places a 0.5 mK limit on uncorrelated fluctuations (sky-roughness) in the 3 K background on an angular scale of the antenna beam width, about 7 degrees.

  13. Effect of early external X-ray radiation on arterial restenosis post percutaneous transluminal angioplasty

    PubMed Central

    Cheng, Jun; Liu, Bujin; Yu, Huarong; Fu, Qining; Li, Fenghe; Zhao, Yu

    2015-01-01

    Background: Arterial restenosis after percutaneous transluminal angioplasty (PTA) significantly reduces its therapeutic efficacy in treating lower extremity atherosclerotic occlusive diseases (LEAOD). Early external X-ray external radiation has demonstrated positive effects on restenosis; however, effective dosing and the mechanism(s) underlying its efficacy remain unknown. This study explored the effect of early external X-ray radiation on preventing post-PTA restenosis in an iliac intimal injury model. Methods: Twenty rabbits underwent iliac intimal injury via PTA and received five different radiation doses: 0 Gy (n=4), 3 Gy (n=4), 6 Gy (n=4), 9 Gy (n=4), and 12 Gy (n=4). Four rabbits were used as controls. All subjects were fed a high-fat diet prior to PTA and for an additional four-week period post-PTA and then sacrificed for immunohistochemical and Western blotting analysis. Results: Arterial stenosis was significantly improved post-PTA. Alpha smooth muscle actin (α-SMA) expression in the 0 Gy to 9 Gy groups was significantly increased post-PTA. Cytochrome C (Cyt C) expression was significantly increased post-PTA and was positively correlated with radiation intensity. Proliferating cell nuclear antigen (PCNA) expression was significantly increased post-PTA with the 0 Gy group showing significantly higher expression than the 3 Gy group. No significant differences were found in CD34 levels between the groups. Conclusions: Early external X-ray radiation at 6-24 Gy doses effectively restrained VSMC hyperplasia post-PTA, likely through inducing VSMC apoptosis via mitochondrial Cyt C release. However, this technique did not significantly affect the integrity of the vascular endothelium. Therefore, early external X-ray radiation shows promise in preventing post-PTA restenosis. PMID:26628976

  14. The effect of early external X-ray radiation on arterial restenosis post percutaneous transluminal angioplasty

    PubMed Central

    Cheng, Jun; Liu, Bujin; Yu, Huarong; Fu, Qining; Li, Fenghe; Zhao, Yu

    2015-01-01

    Background: Arterial restenosis after percutaneous transluminal angioplasty (PTA) significantly reduces its therapeutic efficacy in treating lower extremity atherosclerotic occlusive diseases (LEAOD). Early external X-ray external radiation has demonstrated positive effects on restenosis; however, effective dosing and the mechanism(s) underlying its efficacy remain unknown. This study explored the effect of early external X-ray radiation on preventing post-PTA restenosis in an iliac intimal injury model. Methods: Twenty rabbits underwent iliac intimal injury via PTA and received five different radiation doses: 0 Gy (n = 4), 3 Gy (n = 4), 6 Gy (n = 4), 9 Gy (n = 4), and 12 Gy (n = 4). Four rabbits were used as controls. All subjects were fed a high-fat diet prior to PTA and for an additional four-week period post-PTA and then sacrificed for immunohistochemical and Western blotting analysis. Results: Arterial stenosis was significantly improved post-PTA. Alpha smooth muscle actin (α-SMA) expression in the 0 Gy to 9 Gy groups was significantly increased post-PTA. Cytochrome C (Cyt C) expression was significantly increased post-PTA and was positively correlated with radiation intensity. Proliferating cell nuclear antigen (PCNA) expression was significantly increased post-PTA with the 0 Gy group showing significantly higher expression than the 3 Gy group. No significant differences were found in CD34 levels between the groups. Conclusions: Early external X-ray radiation at 6-24 Gy doses effectively restrained VSMC hyperplasia post-PTA, likely through inducing VSMC apoptosis via mitochondrial Cyt C release. However, this technique did not significantly affect the integrity of the vascular endothelium. Therefore, early external X-ray radiation shows promise in preventing post-PTA restenosis. PMID:26380003

  15. Early test facilities and analytic methods for radiation shielding: Proceedings

    SciTech Connect

    Ingersoll, D.T. ); Ingersoll, J.K. )

    1992-11-01

    This report represents a compilation of eight papers presented at the 1992 American Nuclear Society/European Nuclear Society International Meeting. The meeting is of special significance since it commemorates the fiftieth anniversary of the first controlled nuclear chain reaction. The papers contained in this report were presented in a special session organized by the Radiation Protection and Shielding Division in keeping with the historical theme of the meeting. The paper titles are good indicators of their content and are: (1) The origin of radiation shielding research: The Oak Ridge experience, (2) Shielding research at the hanford site, (3) Aircraft shielding experiments at General Dynamics Fort Worth, 1950-1962, (4) Where have the neutrons gone , a history of the tower shielding facility, (5) History and evolution of buildup factors, (6) Early shielding research at Bettis atomic power laboratory, (7) UK reactor shielding: then and now, (8) A very personal view of the development of radiation shielding theory.

  16. Primordial Gravitational Waves and Rescattered Electromagnetic Radiation in the Cosmic Microwave Background

    NASA Astrophysics Data System (ADS)

    Kim, Dong-Hoon; Trippe, Sascha

    2016-10-01

    Understanding the interaction of primordial gravitational waves (GWs) with the Cosmic Microwave Background (CMB) plasma is important for observational cosmology. In this article, we provide an analysis of an apparently as-yet-overlooked effect. We consider a single free electric charge and suppose that it can be agitated by primordial GWs propagating through the CMB plasma, resulting in periodic, regular motion along particular directions. Light reflected by the charge will be partially polarized, and this will imprint a characteristic pattern on the CMB. We study this effect by considering a simple model in which anisotropic incident electromagnetic (EM) radiation is rescattered by a charge sitting in spacetime perturbed by GWs, and becomes polarized. As the charge is driven to move along particular directions, we calculate its dipole moment to determine the leading-order rescattered EM radiation. The Stokes parameters of the rescattered radiation exhibit a net linear polarization. We investigate how this polarization effect can be schematically represented out of the Stokes parameters. We work out the representations of gradient modes (E-modes) and curl modes (B-modes) to produce polarization maps. Although the polarization effect results from GWs, we find that its representations, the E- and B-modes, do not practically reflect the GW properties such as strain amplitude, frequency, and polarization states.

  17. Stability analysis for the background equations for inflation with dissipation and in a viscous radiation bath

    SciTech Connect

    Bastero-Gil, Mar; Cerezo, Rafael; Berera, Arjun; Ramos, Rudnei O.; Vicente, Gustavo S. E-mail: ab@ph.ed.ac.uk E-mail: rudnei@uerj.br

    2012-11-01

    The effects of bulk viscosity are examined for inflationary dynamics in which dissipation and thermalization are present. A complete stability analysis is done for the background inflaton evolution equations, which includes both inflaton dissipation and radiation bulk viscous effects. Three representative approaches of bulk viscous irreversible thermodynamics are analyzed: the Eckart noncausal theory, the linear and causal theory of Israel-Stewart and a more recent nonlinear and causal bulk viscous theory. It is found that the causal theories allow for larger bulk viscosities before encountering an instability in comparison to the noncausal Eckart theory. It is also shown that the causal theories tend to suppress the radiation production due to bulk viscous pressure, because of the presence of relaxation effects implicit in these theories. Bulk viscosity coefficients derived from quantum field theory are applied to warm inflation model building and an analysis is made of the effects to the duration of inflation. The treatment of bulk pressure would also be relevant to the reheating phase after inflation in cold inflation dynamics and during the radiation dominated regime, although very little work in both areas has been done; the methodology developed in this paper could be extended to apply to these other problems.

  18. Measured Radiation and Background Levels During Transmission of Megawatt Electron Beams Through Millimeter Apertures

    SciTech Connect

    Alarcon, Ricardo; Balascuta, S.; Benson, Stephen V.; Bertozzi, William; Boyce, James R.; Cowan, Ray; Douglas, David R.; Evtushenko, Pavel; Fisher, P.; Ihloff, Ernest E.; Kalantarians, Narbe; Kelleher, Aidan Michael; Krossler, W. J.; Legg, Robert A.; Long, Elena; Milner, Richard; Neil, George R.; Ou, Longwu; Schmookler, Barack Abraham; Tennant, Christopher D.; Tschalar, C.; Williams, Gwyn P.; Zhang, Shukui

    2013-11-01

    We report measurements of photon and neutron radiation levels observed while transmitting a 0.43 MW electron beam through millimeter-sized apertures and during beam-off, but accelerating gradient RF-on, operation. These measurements were conducted at the Free-Electron Laser (FEL) facility of the Jefferson National Accelerator Laboratory (JLab) using a 100 MeV electron beam from an energy-recovery linear accelerator. The beam was directed successively through 6 mm, 4 mm, and 2 mm diameter apertures of length 127 mm in aluminum at a maximum current of 4.3 mA (430 kW beam power). This study was conducted to characterize radiation levels for experiments that need to operate in this environment, such as the proposed DarkLight Experiment. We find that sustained transmission of a 430 kW continuous-wave (CW) beam through a 2 mm aperture is feasible with manageable beam-related backgrounds. We also find that during beam-off, RF-on operation, multipactoring inside the niobium cavities of the accelerator cryomodules is the primary source of ambient radiation when the machine is tuned for 130 MeV operation.

  19. Enhancement of natural background gamma-radiation dose around uranium microparticles in the human body.

    PubMed

    Pattison, John E; Hugtenburg, Richard P; Green, Stuart

    2010-04-01

    Ongoing controversy surrounds the adverse health effects of the use of depleted uranium (DU) munitions. The biological effects of gamma-radiation arise from the direct or indirect interaction between secondary electrons and the DNA of living cells. The probability of the absorption of X-rays and gamma-rays with energies below about 200 keV by particles of high atomic number is proportional to the third to fourth power of the atomic number. In such a case, the more heavily ionizing low-energy recoil electrons are preferentially produced; these cause dose enhancement in the immediate vicinity of the particles. It has been claimed that upon exposure to naturally occurring background gamma-radiation, particles of DU in the human body would produce dose enhancement by a factor of 500-1000, thereby contributing a significant radiation dose in addition to the dose received from the inherent radioactivity of the DU. In this study, we used the Monte Carlo code EGSnrc to accurately estimate the likely maximum dose enhancement arising from the presence of micrometre-sized uranium particles in the body. We found that although the dose enhancement is significant, of the order of 1-10, it is considerably smaller than that suggested previously.

  20. Genetic Background Modulates lncRNA-Coordinated Tissue Response to Low Dose Ionizing Radiation

    DOE PAGESBeta

    Tang, Jonathan; Huang, Yurong; Nguyen, David H.; Costes, Sylvain V.; Snijders, Antoine M.; Mao, Jian-Hua

    2015-01-01

    Long noncoding RNAs (lncRNAs) are emerging as key regulators of diverse cell functions and processes. However, the relevance of lncRNAs in the cell and tissue response to ionizing radiation has not yet been characterized. Here we used microarray profiling to determine lncRNA and mRNA expression in mammary glands of BALB/c and SPRET/EiJ mice after low-dose ionizing radiation (LDIR) exposure. We found that unirradiated mammary tissues of these strains differed significantly in baseline expressions of 290 lncRNAs. LDIR exposure (10 cGy) induced a significant change in the expression of many lncRNAs. The vast majority of lncRNAs identified to be differentially expressed aftermore » LDIR in either BALB/c or SPRET/EiJ had a significantly correlated expression pattern with at least one LDIR responsive mRNA. Functional analysis revealed that the response to LDIR in BALB/c mice is highly dynamic with enrichment for genes involved in tissue injury, inflammatory responses, and mammary gland development at 2, 4, and 8 weeks after LDIR, respectively. Our study demonstrates that genetic background strongly influences the expression of lncRNAs and their response to radiation and that lncRNAs may coordinate the tissue response to LDIR exposure via regulation of coding mRNAs.« less

  1. Enhancement of natural background gamma-radiation dose around uranium microparticles in the human body

    PubMed Central

    Pattison, John E.; Hugtenburg, Richard P.; Green, Stuart

    2010-01-01

    Ongoing controversy surrounds the adverse health effects of the use of depleted uranium (DU) munitions. The biological effects of gamma-radiation arise from the direct or indirect interaction between secondary electrons and the DNA of living cells. The probability of the absorption of X-rays and gamma-rays with energies below about 200 keV by particles of high atomic number is proportional to the third to fourth power of the atomic number. In such a case, the more heavily ionizing low-energy recoil electrons are preferentially produced; these cause dose enhancement in the immediate vicinity of the particles. It has been claimed that upon exposure to naturally occurring background gamma-radiation, particles of DU in the human body would produce dose enhancement by a factor of 500–1000, thereby contributing a significant radiation dose in addition to the dose received from the inherent radioactivity of the DU. In this study, we used the Monte Carlo code EGSnrc to accurately estimate the likely maximum dose enhancement arising from the presence of micrometre-sized uranium particles in the body. We found that although the dose enhancement is significant, of the order of 1–10, it is considerably smaller than that suggested previously. PMID:19776147

  2. The impact of solar UV radiation on the early biosphere

    NASA Astrophysics Data System (ADS)

    Horneck, G.

    2007-08-01

    Stratospheric ozone, photochemically produced from atmospheric oxygen, is a protective filter of the Earth's atmosphere by absorbing most of the biologically harmful UV radiation of our sun in the UV-C (190-280 nm) and short wavelength-region of the UV-B (280-315 nm). Numerous lines of isotopic and geologic evidence suggest that the Archean atmosphere was essentially anoxic. As a result the column abundance of ozone would have been insufficient to affect the surface UV radiation environment. Thus, as well as UV-B radiation, UV-C radiation would have penetrated to the Earth's surface with its associated biological consequences. The history of this ultraviolet stress for the early Earth has been determined from theoretical data and data obtained in Earth orbit on the inactivation of Bacillus subtilis spores under a simulated ozone layer of different thicknesses. Although the UV-C and UV-B regions contribute only 2 % of the entire solar extraterrestrial irradiance, photobiological experiments in space have demonstrated a high mutagenicity and lethality of this UV range to living organisms. The reason for these severe effects of extraterrestrial solar UV radiation - compared to conditions on present-day Earth - lies in the absorption characteristics of the DNA, which is the decisive target for inactivation and mutation induction at this UV range. Being a strong mutagen, UV-radiation is considered as a powerful promoter of biological evolution on the one hand, one the other hand, it may have deleterious consequences to individual cells and organisms, e.g. by causing inactivation, mutations or cancer induction. In response to potential harmful effects of environmental UV radiation, life on Earth has developed several strategies of survival, either avoiding exposure to UV radiation or restoring UV damage. Mechanisms of avoidance of exposure to UV radiation include (i) moving away from the UV radiation into shadowed areas, which requires the development of UV radiation

  3. Background- versus event-level biotic variability: Hyperthermals of the late Paleocene and early Eocene

    NASA Astrophysics Data System (ADS)

    Gibbs, S.; Murphy, B. H.; Pälike, H.

    2009-12-01

    The Paleocene-Eocene Thermal Maximum (PETM) was an abrupt global warming event 55 million years ago (Ma) which has received much attention in recent years as an analogue for anthropogenic carbon emissions. We now know that the PETM was not unique, but was perhaps the most extreme of a number of abrupt carbon cycle perturbations throughout the late Paleocene and early Eocene. These inferred transient warming events, or ‘hyperthermals’, all have characteristic negative carbon isotope excursions (CIE). Unlike the PETM, it is currently unclear whether there was a significant biotic response to these additional CIEs, and if so, whether the amplitude of response varied systematically with excursion magnitude. Here, we present high-resolution nannofossil records from a two million year interval spanning the Paleocene-Eocene boundary at Ocean Drilling Program (ODP) Site 1209 in the paleo-subequatorial Pacific. This interval, from ~55 to 53 Ma, includes the PETM, a second hyperthermal named the Eocene Thermal Maximum 2 (ETM2 or ‘Elmo’), and a further number of smaller excursions. These data allow us to look for common biotic signatures and to document the level of assemblage variability relative to the inferred levels of environmental change associated with each CIE. We use this dataset as a case-study for investigating different statistical means of quantifying and comparing biotic responses to background and event-level perturbation. Preliminary analyses suggest that, as expected, the PETM exhibited the greatest level of assemblage variability, well above background levels, followed in order of CIE magnitude by the ETM2. Several of the smaller excursions have no significant assemblage variability above background levels, pointing to a critical threshold level of environmental perturbation.

  4. Constraints on nonconformal couplings from the properties of the cosmic microwave background radiation.

    PubMed

    van de Bruck, Carsten; Morrice, Jack; Vu, Susan

    2013-10-18

    Certain modified gravity theories predict the existence of an additional, nonconformally coupled scalar field. A disformal coupling of the field to the cosmic microwave background (CMB) is shown to affect the evolution of the energy density in the radiation fluid and produces a modification of the distribution function of the CMB, which vanishes if photons and baryons couple in the same way to the scalar. We find the constraints on the couplings to matter and photons coming from the measurement of the CMB temperature evolution and from current upper limits on the μ distortion of the CMB spectrum. We also point out that the measured equation of state of photons differs from w(γ)=1/3 in the presence of disformal couplings.

  5. Southern Hemisphere measurements of the anisotropy in the cosmic microwave background radiation

    NASA Technical Reports Server (NTRS)

    Smoot, G. F.; Lubin, P. M.

    1979-01-01

    A recent airborne measurement of the large-angular-scale anisotropy in the cosmic background radiation from the Southern Hemisphere (Lima, Peru) is in essential agreement with previous measurements from the northern hemisphere. The net anisotropy from the combined data can be described by a first-order spherical harmonic (Doppler) anisotropy of amplitude 3.1 plus or minus 0.4 mK with a quadrupole component of less than 1 mK. Additional ground-based measurements of the linear polarization yield an upper limit of l mK, or one part in 3000, at 95% confidence level for the amplitudes of any spherical harmonic through third order.

  6. Anisotropy of the Cosmic Microwave Background Radiation on Large and Medium Angular Scales

    NASA Technical Reports Server (NTRS)

    Houghton, Anthony; Timbie, Peter

    1998-01-01

    This grant has supported work at Brown University on measurements of the 2.7 K Cosmic Microwave Background Radiation (CMB). The goal has been to characterize the spatial variations in the temperature of the CMB in order to understand the formation of large-scale structure in the universe. We have concurrently pursued two measurements using millimeter-wave telescopes carried aloft by scientific balloons. Both systems operate over a range of wavelengths, chosen to allow spectral removal of foreground sources such as the atmosphere, Galaxy, etc. The angular resolution of approx. 25 arcminutes is near the angular scale at which the most structure is predicted by current models to be visible in the CMB angular power spectrum. The main goal is to determine the angular scale of this structure; in turn we can infer the density parameter, Omega, for the universe as well as other cosmological parameters, such as the Hubble constant.

  7. Constraints on nonconformal couplings from the properties of the cosmic microwave background radiation.

    PubMed

    van de Bruck, Carsten; Morrice, Jack; Vu, Susan

    2013-10-18

    Certain modified gravity theories predict the existence of an additional, nonconformally coupled scalar field. A disformal coupling of the field to the cosmic microwave background (CMB) is shown to affect the evolution of the energy density in the radiation fluid and produces a modification of the distribution function of the CMB, which vanishes if photons and baryons couple in the same way to the scalar. We find the constraints on the couplings to matter and photons coming from the measurement of the CMB temperature evolution and from current upper limits on the μ distortion of the CMB spectrum. We also point out that the measured equation of state of photons differs from w(γ)=1/3 in the presence of disformal couplings. PMID:24182251

  8. Constraints on Nonconformal Couplings from the Properties of the Cosmic Microwave Background Radiation

    NASA Astrophysics Data System (ADS)

    van de Bruck, Carsten; Morrice, Jack; Vu, Susan

    2013-10-01

    Certain modified gravity theories predict the existence of an additional, nonconformally coupled scalar field. A disformal coupling of the field to the cosmic microwave background (CMB) is shown to affect the evolution of the energy density in the radiation fluid and produces a modification of the distribution function of the CMB, which vanishes if photons and baryons couple in the same way to the scalar. We find the constraints on the couplings to matter and photons coming from the measurement of the CMB temperature evolution and from current upper limits on the μ distortion of the CMB spectrum. We also point out that the measured equation of state of photons differs from wγ=1/3 in the presence of disformal couplings.

  9. Measurement of the large-scale anisotropy of the cosmic background radiation at 3mm

    SciTech Connect

    Epstein, G.L.

    1983-12-01

    A balloon-borne differential radiometer has measured the large-scale anisotropy of the cosmic background radiation (CBR) with high sensitivity. The antenna temperature dipole anistropy at 90 GHz (3 mm wavelength) is 2.82 +- 0.19 mK, corresponding to a thermodynamic anistropy of 3.48 +- mK for a 2.7 K blackbody CBR. The dipole direction, 11.3 +- 0.1 hours right ascension and -5.7/sup 0/ +- 1.8/sup 0/ declination, agrees well with measurements at other frequencies. Calibration error dominates magnitude uncertainty, with statistical errors on dipole terms being under 0.1 mK. No significant quadrupole power is found, placing a 90% confidence-level upper limit of 0.27 mK on the RMS thermodynamic quadrupolar anistropy. 22 figures, 17 tables.

  10. Precise measurement of the matter power spectrum amplitude and the background radiation amplitude

    NASA Astrophysics Data System (ADS)

    Jena, Tridivesh

    2004-09-01

    We investigate the one dimensional flux power spectrum of the Lymanα forest and compare it with Lymanα forest simulations using state of the art hydrodynamical simulations. We investigate how properties of the forest, such as the mean flux , b parameter distribution (specifically, the mode of the b parameter distribution, bmode) and flux power amplitude [P], depend on cosmological and astrophysical parameters such as σ8, the background UV radiation amplitude J, and the Helium reheating rate Jhe. We present our results of scaling relationships between the cosmological and astrophysical variables, J, σ8, Jhe, and observable astrophysical values, , [P], bmode. These scaling relations are used to determine the best fit values of the cosmological parameters; J = 1.1, σ8 = 0.93 and Jhe = 2.6. These values are remarkably close to the best fit values found by using WMAP data.

  11. Output of acoustical sources. [effects of structural elements and background flow on immobile multipolar point radiation

    NASA Technical Reports Server (NTRS)

    Levine, H.

    1980-01-01

    Acoustic radiation from a source, here viewed as an immobile point singularity with periodic strength and a given multipolar nature, is affected by the presence of nearly structural elements (e.g., rigid or impedance surfaces) as well as that of a background flow in the medium. An alternative to the conventional manner of calculating the net source output by integrating the energy flux over a distant control surface is described; this involves a direct evaluation of the secondary wavefunction at the position of the primary source and obviates the need for a (prospectively difficult) flux integration. Various full and half-planar surface configurations with an adjacent source are analyzed in detail, and the explicit results obtained, in particular, for the power factor of a dipole brings out a substantial rise in its output as the source nears the sharp edge of a half-plane.

  12. Cosmic background radiation anisotropies in universes dominated by nonbaryonic dark matter

    NASA Technical Reports Server (NTRS)

    Bond, J. R.; Efstathiou, G.

    1984-01-01

    Detailed calculations of the temperature fluctuations in the cosmic background radiation for universes dominated by massive collisionless relics of the big bang are presented. An initially adiabatic constant curvature perturbation spectrum is assumed. In models with cold dark matter, the simplest hypothesis - that galaxies follow the mass distribution leads to small-scale anisotropies which exceed current observational limits if omega is less than 0.2 h to the -4/3. Since low values of omega are indicated by dynamical studies of galaxy clustering, cold particle models in which light traces mass are probably incorrect. Reheating of the pregalactic medium is unlikely to modify this conclusion. In cold particle or neutrino-dominated universes with omega = 1, presented predictions for small-scale and quadrupole anisotropies are below current limits. In all cases, the small-scale fluctuations are predicted to be about 10 percent linearly polarized.

  13. A comparative study of thorium activity in NORM and high background radiation area.

    PubMed

    Sahoo, S K; Ishikawa, T; Tokonami, S; Sorimachi, A; Kranrod, C; Janik, M; Hosoda, M; Hassan, N M; Chanyotha, S; Parami, V K; Yonehara, H; Ramola, R C

    2010-10-01

    Several industrial processes are known to enrich naturally occurring radioactive materials (NORM). To assess such processes with respect to their radiological relevance, characteristic parameters describing this enrichment will lead to interesting information useful to UNSCEAR. In case of mineral treatment plants, the high temperatures used in smelting and refining processes lead to high concentrations of (238)U and (232)Th. Also due to thermal power combustion, concentration of U and Th in the fly ash increases manifold. NORM samples were collected from a Thailand mineral treatment plant and Philippine coal-fired thermal power plants for investigation. Some studies are initiated from a high background radiation area near Gopalpur of Orissa state in India. These NORM samples were analysed by gamma-ray spectrometry as well as inductively coupled plasma mass spectrometry. The radioactivity in case of Orissa soil samples is found to be mainly contributed from thorium. This study attempts to evaluate levels of thorium activity in NORM samples.

  14. Measurement of the intensity of the cosmic background radiation at 3. 0 cm

    SciTech Connect

    Friedman, S.D.

    1984-01-01

    The intensity of the cosmic background radiation (CBR) has been measured at a wavelength of 3.0 cm as part of a program to measure th Rayleigh-Jeans spectrum of the CBR at five wavelengths between 0.33 cm and 12 cm. The instrument used is a dual-antenna Dicke-switched radiometer with a double-sideband noise temperature of 490 K and a sensitivity of 46 mK/Hz/sup 1/2/. The entire radiometer is mounted on bearings. The atmospheric emission was measured by rotating the radiometer, and thus directing one antenna to zenith angles of +- 30/sup 0/ and +- 40/sup 0/. 61 references, 24 figures, 18 tables.

  15. Cosmic background radiation in the vicinity of a Schwarzschild black hole: No classic firewall

    NASA Astrophysics Data System (ADS)

    Wielgus, M.; Ellis, G. F. R.; Vincent, F. H.; Abramowicz, M. A.

    2014-12-01

    The cosmic blackbody background radiation pervades the entire Universe, and so falls into every astrophysical black hole. The blueshift of the infalling photons, measured by a static observer, is infinite at the event horizon. This raises a question as to whether a "firewall" of high energy density may form just outside the horizon, or whether the effect can be attributed exclusively to a singular behavior of the static observer's frame at the horizon. In principle, the presence of such a firewall may alter the motion of the infalling matter, influence the black hole evolution, or even invalidate the vacuum Einstein field equation solution as a realistic approximation for black holes. In this paper we show by means of analytic calculations that all these effects indeed exist, but their magnitude is typically negligibly small, even though the matter stress tensor is divergent in the static frame at r =2 M . That is not surprising because of the divergent relation of that frame to a freely falling frame as r →2 M ; however, it represents a kind of classical analogue for the black hole complementarity principle that has been proposed for quantum effects near a black hole. What is perhaps more surprising is the divergence of the radiation stress tensor for massive particles moving on circular geodesic orbits for values of r approaching r =3 M . However such orbits will not occur for infalling matter in realistic accretion discs.

  16. An Analysis of Recent Measurements of the Temperature of the Cosmic Microwave Background Radiation

    DOE R&D Accomplishments Database

    Smoot, G.; Levin, S. M.; Witebsky, C.; De Amici, G.; Rephaeli, Y.

    1987-07-01

    This paper presents an analysis of the results of recent temperature measurements of the cosmic microwave background radiation (CMBR). The observations for wavelengths longer than 0.1 cum are well fit by a blackbody spectrum at 2.74{+ or -}0.0w K; however, including the new data of Matsumoto et al. (1987) the result is no longer consistent with a Planckian spectrum. The data are described by a Thomson-distortion parameter u=0.021{+ or -}0.002 and temperature 2.823{+ or -}0.010 K at the 68% confidence level. Fitting the low-frequency data to a Bose-Einstein spectral distortion yields a 95% confidence level upper limit of 1.4 x 10{sup -2} on the chemical potential mu{sub 0}. These limits on spectral distortions place restrictions on a number of potentially interesting sources of energy release to the CMBR, including the hot intergalactic medium proposed as the source of the X-ray background.

  17. Reduced Ovarian Cancer Incidence in Women Exposed to Low Dose Ionizing Background Radiation or Radiation to the Ovaries after Treatment for Breast Cancer or Rectosigmoid Cancer

    PubMed Central

    Lehrer, Steven; Green, Sheryl; Rosenzweig, Kenneth E

    2016-01-01

    Background High dose ionizing radiation can induce ovarian cancer, but the effect of low dose radiation on the development of ovarian cancer has not been extensively studied. We evaluated the effect of low dose radiation and total background radiation, and the radiation delivered to the ovaries during the treatment of rectosigmoid cancer and breast cancer on ovarian cancer incidence. Materials and Methods Background radiation measurements are from Assessment of Variations in Radiation Exposure in the United States, 2011. Ovarian cancer incidence data are from the Centers for Disease Control and Prevention. Standardized incidence ratios (SIR) of ovarian cancer following breast cancer and rectosigmoid cancer are from Surveillance, Epidemiology, and End Results (SEER) data. Obesity data by US state are from the Centers for Disease Control and Prevention. Mean ages of US state populations are from the United States Census Bureau. Results We calculated standardized incidence ratios (SIR) from Surveillance, Epidemiology, and End Results (SEER) data, which reveal that in 194,042 cases of breast cancer treated with beam radiation, there were 796 cases of ovarian cancer by 120+ months of treatment (0.41%); in 283, 875 cases of breast cancer not treated with radiation, there were 1,531 cases of ovarian cancer by 120+ months (0.54%). The difference in ovarian cancer incidence in the two groups was significant (p < 0.001, two tailed Fisher exact test). The small dose of scattered ovarian radiation (about 3.09 cGy) from beam radiation to the breast appears to have reduced the risk of ovarian cancer by 24%. In 13,099 cases of rectal or rectosigmoid junction cancer treated with beam radiation in the SEER data, there were 20 cases of ovarian cancer by 120+ months of treatment (0.15%). In 33,305 cases of rectal or rectosigmoid junction cancer not treated with radiation, there were 91 cases of ovarian cancer by 120+ months (0.27%). The difference in ovarian cancer incidence in the

  18. Space weather circulation model of plasma clouds as background radiation medium of space environment.

    NASA Astrophysics Data System (ADS)

    Kalu, A. E.

    A model for Space Weather (SW) Circulation with Plasma Clouds as background radiation medium of Space Environment has been proposed and discussed. Major characteristics of the model are outlined and the model assumes a baroclinic Space Environment in view of observed pronounced horizontal electron temperature gradient with prevailing weak vertical temperature gradient. The primary objective of the study is to be able to monitor and realistically predict on real- or near real-time SW and Space Storms (SWS) affecting human economic systems on Earth as well as the safety and Physiologic comfort of human payload in Space Environment in relation to planned increase in human space flights especially with reference to the ISS Space Shuttle Taxi (ISST) Programme and other prolonged deep Space Missions. Although considerable discussions are now available in the literature on SW issues, routine Meteorological operational applications of SW forecast data and information for Space Environment are still yet to receive adequate attention. The paper attempts to fill this gap in the literature of SW. The paper examines the sensitivity and variability in 3-D continuum of Plasmas in response to solar radiation inputs into the magnetosphere under disturbed Sun condition. Specifically, the presence of plasma clouds in the form of Coronal Mass Ejections (CMEs) is stressed as a major source of danger to Space crews, spacecraft instrumentation and architecture charging problems as well as impacts on numerous radiation - sensitive human economic systems on Earth. Finally, the paper considers the application of model results in the form of effective monitoring of each of the two major phases of manned Spaceflights - take-off and re-entry phases where all-time assessment of spacecraft transient ambient micro-incabin and outside Space Environment is vital for all manned Spaceflights as recently evidenced by the loss of vital information during take-off of the February 1, 2003 US Columbia

  19. Aerosol optical, microphysical and radiative properties at regional background insular sites in the western Mediterranean

    NASA Astrophysics Data System (ADS)

    Sicard, Michaël; Barragan, Rubén; Dulac, François; Alados-Arboledas, Lucas; Mallet, Marc

    2016-09-01

    In the framework of the ChArMEx (the Chemistry-Aerosol Mediterranean Experiment; http://charmex.lsce.ipsl.fr/) program, the seasonal variability of the aerosol optical, microphysical and radiative properties derived from AERONET (Aerosol Robotic Network; http://aeronet.gsfc.nasa.gov/) is examined in two regional background insular sites in the western Mediterranean Basin: Ersa (Corsica Island, France) and Palma de Mallorca (Mallorca Island, Spain). A third site, Alborán (Alborán Island, Spain), with only a few months of data is considered for examining possible northeast-southwest (NE-SW) gradients of the aforementioned aerosol properties. The AERONET dataset is exclusively composed of level 2.0 inversion products available during the 5-year period 2011-2015. AERONET solar radiative fluxes are compared with ground- and satellite-based flux measurements. To the best of our knowledge this is the first time that AERONET fluxes are compared with measurements at the top of the atmosphere. Strong events (with an aerosol optical depth at 440 nm greater than 0.4) of long-range transport aerosols, one of the main drivers of the observed annual cycles and NE-SW gradients, are (1) mineral dust outbreaks predominant in spring and summer in the north and in summer in the south and (2) European pollution episodes predominant in autumn. A NE-SW gradient exists in the western Mediterranean Basin for the aerosol optical depth and especially its coarse-mode fraction, which all together produces a similar gradient for the aerosol direct radiative forcing. The aerosol fine mode is rather homogeneously distributed. Absorption properties are quite variable because of the many and different sources of anthropogenic particles in and around the western Mediterranean Basin: North African and European urban areas, the Iberian and Italian peninsulas, most forest fires and

  20. Analysis of small-scale microwave background radiation anisotropy in the presence of foreground contamination

    NASA Technical Reports Server (NTRS)

    Dodelson, Scott; Stebbins, Albert

    1994-01-01

    Many of the current round of experiments searching for anisotropies in the microwave background radiation (MBR) are confronting the problem of how to disentangle the cosmic signal from contamination due to Galactic and intergalactic foreground sources. Here we show how commonly used likelihood function techniques can be generalized to account for foreground. Specifically we set some restrictions on the spectrum of foreground contamination but allow the amplitude to vary arbitrarily. The likelihood function thus generalized gives reasonable limits on the MBR anisotropy which, in some cases, are not much less restrictive than what one would get from more detailed modeling of the foreground. Furthermore, the likelihood function is exactly the same as one would obtain by simply projecting out foreground contamination and looking at the reduced data set. We apply this generalized analysis to the recent medium-angle data sets of ACME-HEMT (Gaier et al. 1992; Schuster et al. 1993) and MAX (Meinhold et al. 1993; Gunderson et al. 1993). The resulting analysis constrains the one free parameter in the standard cold dark matter theory to be Q(sub rms-ps) = 18(sub -5 sup +8) microKelvin. This best fit value, although in striking agreement with the normalization from Cosmic Background Explorer (COBE), is not a very good fit, with an overall chi-squared/degrees of freedom = 208/168. We also argue against three commonly used methods of dealing with foreground: (1) ignoring it completely; (2) subtracting off a best-fit foreground and treating the residuals as if uncontaminated; and (3) culling data which appears to be contaminated by foreground.

  1. A measurement of the medium-scale anisotropy in the cosmic microwave background radiation

    NASA Technical Reports Server (NTRS)

    Cheng, E. S.; Cottingham, D. A.; Fixsen, D. J.; Inman, C. A.; Kowitt, M. S.; Meyer, S. S.; Page, L. A.; Puchalla, J. L.; Silverberg, R. F.

    1994-01-01

    Observations from the first flight of the Medium Scale Anisotropy Measurement (MSAM) are analyzed to place limits on Gaussian fluctuations in the cosmic microwave background radiation (CMBR). This instrument chops a 30 min beam in a three-position pattern with a throw of +/- 40 min; the resulting data is analyzed in statistically independent single- and double-difference sets. We observe in four spectral channels at 5.6, 9.0, 16.5, and 22.5/cm, allowing the separation of interstellar dust emission from CMBR fluctuations. The dust component is correlated with the IRAS 100 micron map. The CMBR component has two regions where the signature of an unresolved source is seen. Rejecting these two source regions, we obtain a detection of fluctuations which match CMBR in our spectral bands of 0.6 x 10(exp -5) is less than Delta (T)/T is less than 2.2 x 10(exp -5) (90% CL interval) for total rms Gaussian fluctuations with correlation angle 0.5 deg, using the single-difference demodulation. Fore the double difference demodulation, the result is 1.1 x 10(exp -5) is less than Delta(T)/T is less than 3.1 x 10(exp -5) (90% CL interval) at a correlation angle of 0.3 deg.

  2. Background radiation and individual dosimetry in the costal area of Tamil Nadu, India.

    PubMed

    Matsuda, Naoki; Brahmanandhan, G M; Yoshida, Masahiro; Takamura, Noboru; Suyama, Akihiko; Koguchi, Yasuhiro; Juto, Norimichi; Raj, Y Lenin; Winsley, Godwin; Selvasekarapandian, S

    2011-07-01

    South coast of India is known as the high-level background radiation area (HBRA) mainly due to beach sands that contain natural radionuclides as components of the mineral monazite. The rich deposit of monazite is unevenly distributed along the coastal belt of Tamil Nadu and Kerala. An HBRA site that laid in 2×7 m along the sea was found in the beach of Chinnavillai, Tamil Nadu, where the maximum ambient dose equivalent reached as high as 162.7 mSv y(-1). From the sands collected at the HBRA spot, the high-purity germanium semi-conductor detector identified six nuclides of thorium series, four nuclides of uranium series and two nuclides belonging to actinium series. The highest radioactivity observed was 43.7 Bq g(-1) of Th-228. The individual dose of five inhabitants in Chinnavillai, as measured by the radiophotoluminescence glass dosimetry system, demonstrated the average dose of 7.17 mSv y(-1) ranging from 2.79 to 14.17 mSv y(-1).

  3. Spatial variations in natural background radiation: absorbed dose rates in air in Colorado.

    PubMed

    Stone, J M; Whicker, R D; Ibrahim, S A; Whicker, F W

    1999-05-01

    Large and small-scale spatial variations in natural ambient background radiation dose rates in Colorado were investigated at 1,150 specific locations with particular attention to 40 of the more populated areas along the Front Range of the Rocky Mountains. Total dose rates (including cosmic and terrestrial components) in Front Range communities below 2,000 m elevation averaged 135 nGy h(-1). Terrestrial dose rates had a coefficient of variation of 17%. Communities above 2,000 m had a mean total dose rate of 196 nGy h(-1), and a terrestrial dose rate coefficient of variation of 17%. Across all Front Range communities, the coefficient of variation for terrestrial dose rates was 22%. Within individual communities, coefficient of variation values for terrestrial dose rates ranged from 3 to 21%. Smaller-scale spatial variability (to within a few meters) was relatively small (coefficient of variation values generally ranged from 3 to 7%). A significant linear relationship (r2 = 0.83) between the size of area surveyed (km2) and coefficient of variation value for terrestrial dose rates was found. West of the Continental Divide, the terrestrial component accounted for roughly 60% of total measured dose rates, while east of the Continental Divide, where enriched granitic source rocks and associated soils are prevalent, the terrestrial component generally accounted for two-thirds or more of total dose rates. PMID:10201565

  4. Background radiation and individual dosimetry in the costal area of Tamil Nadu, India.

    PubMed

    Matsuda, Naoki; Brahmanandhan, G M; Yoshida, Masahiro; Takamura, Noboru; Suyama, Akihiko; Koguchi, Yasuhiro; Juto, Norimichi; Raj, Y Lenin; Winsley, Godwin; Selvasekarapandian, S

    2011-07-01

    South coast of India is known as the high-level background radiation area (HBRA) mainly due to beach sands that contain natural radionuclides as components of the mineral monazite. The rich deposit of monazite is unevenly distributed along the coastal belt of Tamil Nadu and Kerala. An HBRA site that laid in 2×7 m along the sea was found in the beach of Chinnavillai, Tamil Nadu, where the maximum ambient dose equivalent reached as high as 162.7 mSv y(-1). From the sands collected at the HBRA spot, the high-purity germanium semi-conductor detector identified six nuclides of thorium series, four nuclides of uranium series and two nuclides belonging to actinium series. The highest radioactivity observed was 43.7 Bq g(-1) of Th-228. The individual dose of five inhabitants in Chinnavillai, as measured by the radiophotoluminescence glass dosimetry system, demonstrated the average dose of 7.17 mSv y(-1) ranging from 2.79 to 14.17 mSv y(-1). PMID:21502300

  5. Doses and risks from uranium are not increased significantly by interactions with natural background photon radiation.

    PubMed

    Tanner, R J; Eakins, J S; Jansen, J T M; Harrison, J D

    2012-08-01

    The impact of depleted uranium (DU) on human health has been the subject of much conjecture. Both the chemical and radiological aspects of its behaviour in the human body have previously been investigated in detail, with the radiological impact being assumed to be linked to the alpha decay of uranium. More recently, it has been proposed that the accumulation in tissue of high-Z materials, such as DU, may give rise to enhanced local energy deposition in the presence of natural background photon radiation due to the high photoelectric interaction cross sections of high-Z atoms. It is speculated that, in addition to producing short-range photoelectrons, these events will be followed by intense Auger and Coster-Kronig electron emission, thereby causing levels of cell damage that are unaccounted for in conventional models of radiological risk. In this study, the physical and biological bases of these claims are investigated. The potential magnitudes of any effect are evaluated and discussed, and compared with the risks from other radiological or chemical hazards. Monte Carlo calculations are performed to estimate likely energy depositions due to the presence of uranium in human tissues in photon fields: whole body doses, organ doses in anthropomorphic phantoms and nano-/micro-dosimetric scenarios are each considered. The proposal is shown generally to be based on sound physics, but overall the impact on human health is expected to be negligible.

  6. Lightning initiation mechanism based on the development of relativistic runaway electron avalanches triggered by background cosmic radiation: Numerical simulation

    SciTech Connect

    Babich, L. P. Bochkov, E. I.; Kutsyk, I. M.

    2011-05-15

    The mechanism of lightning initiation due to electric field enhancement by the polarization of a conducting channel produced by relativistic runaway electron avalanches triggered by background cosmic radiation has been simulated numerically. It is shown that the fields at which the start of a lightning leader is possible even in the absence of precipitations are locally realized for realistic thundercloud configurations and charges. The computational results agree with the in-situ observations of penetrating radiation enhancement in thunderclouds.

  7. A case-referent study on acute myeloid leukemia, background radiation and exposure to solvents and other agents.

    PubMed

    Flodin, U; Andersson, L; Anjou, C G; Palm, U B; Vikrot, O; Axelson, O

    1981-09-01

    The effect of potential risk factors for acute myeloid leukemia was evaluated in a case-referent study encompassing 42 cases and 244 referents, all deceased. Information on exposure was obtained with questionnaires mailed to the next of kin. Particularly the effect of background radiation was evaluated, as assessed with a gamma radiation index weighing the time spent outdoors and indoors and considering the building material (stone, wood, etc.) in the homes and the workplaces of the subjects. Especially between the ages of 20 and 49 a, to some extent also between 50 and 69 a but not above 70, there seemed to be an effect from background radiation and a trend suggesting an exposure-effect relationship. There was also about a sixfold increase in the rate ratio with regard to solvent exposure, which also seemed to modify the effect of background radiation. Other exposures were associated with relatively modest increases in the rate ratios and/or very small numbers of exposed individuals. It would be worthwhile to undertake further cancer epidemiologic studies of background radiation in which effective study designs are applied and a variety of potential confounders and modifiers of effect are identified and accounted for. PMID:20120581

  8. Real-time airborne gamma-ray background estimation using NASVD with MLE and radiation transport for calibration

    NASA Astrophysics Data System (ADS)

    Kulisek, J. A.; Schweppe, J. E.; Stave, S. C.; Bernacki, B. E.; Jordan, D. V.; Stewart, T. N.; Seifert, C. E.; Kernan, W. J.

    2015-06-01

    Helicopter-mounted gamma-ray detectors can provide law enforcement officials the means to quickly and accurately detect, identify, and locate radiological threats over a wide geographical area. The ability to accurately distinguish radiological threat-generated gamma-ray signatures from background gamma radiation in real time is essential in order to realize this potential. This problem is non-trivial, especially in urban environments for which the background may change very rapidly during flight. This exacerbates the challenge of estimating background due to the poor counting statistics inherent in real-time airborne gamma-ray spectroscopy measurements. To address this challenge, we have developed a new technique for real-time estimation of background gamma radiation from aerial measurements without the need for human analyst intervention. The method can be calibrated using radiation transport simulations along with data from previous flights over areas for which the isotopic composition need not be known. Over the examined measured and simulated data sets, the method generated accurate background estimates even in the presence of a strong, 60Co source. The potential to track large and abrupt changes in background spectral shape and magnitude was demonstrated. The method can be implemented fairly easily in most modern computing languages and environments.

  9. The imprint of the cosmic supermassive black hole growth history on the 21 cm background radiation

    NASA Astrophysics Data System (ADS)

    Tanaka, Takamitsu L.; O'Leary, Ryan M.; Perna, Rosalba

    2016-01-01

    The redshifted 21 cm transition line of hydrogen tracks the thermal evolution of the neutral intergalactic medium (IGM) at `cosmic dawn', during the emergence of the first luminous astrophysical objects (˜100 Myr after the big bang) but before these objects ionized the IGM (˜400-800 Myr after the big bang). Because X-rays, in particular, are likely to be the chief energy courier for heating the IGM, measurements of the 21 cm signature can be used to infer knowledge about the first astrophysical X-ray sources. Using analytic arguments and a numerical population synthesis algorithm, we argue that the progenitors of supermassive black holes (SMBHs) should be the dominant source of hard astrophysical X-rays - and thus the primary driver of IGM heating and the 21 cm signature - at redshifts z ≳ 20, if (i) they grow readily from the remnants of Population III stars and (ii) produce X-rays in quantities comparable to what is observed from active galactic nuclei and high-mass X-ray binaries. We show that models satisfying these assumptions dominate over contributions to IGM heating from stellar populations, and cause the 21 cm brightness temperature to rise at z ≳ 20. An absence of such a signature in the forthcoming observational data would imply that SMBH formation occurred later (e.g. via so-called direct collapse scenarios), that it was not a common occurrence in early galaxies and protogalaxies, or that it produced far fewer X-rays than empirical trends at lower redshifts, either due to intrinsic dimness (radiative inefficiency) or Compton-thick obscuration close to the source.

  10. Early Observations of Saturn Kilometric Radiation by Cassini

    NASA Astrophysics Data System (ADS)

    Kurth, W. S.; Hospodarsky, G. B.; Gurnett, D. A.; Desch, M. D.; Kaiser, M. L.; Zarka, P.; Lecacheux, A.

    2002-12-01

    One of the primary objectives of the Cassini radio and plasma wave science investigation at Saturn is the study of Saturn kilometric radio emissions (SKR). Based primarily on Voyager observations, these emissions are believed to be analogous to auroral kilometric radiation at Earth, generated via the cyclotron maser instability near the electron cyclotron frequency on field lines threading Saturn's aurora. Beginning in early 2002, Cassini has observed Saturn's most prominent radio emission on numerous occasions with signal to noise ratios exceeding 10 dB, even though the spacecraft is still more than two astronomical units from Saturn. One specific objective involving SKR is to develop the relationship between the timing and intensity of the radio emissions as a function of solar wind input; strong correlations with various solar wind parameters are already known on the basis of Voyager studies. A second objective is to measure spectral and temporal variations in the SKR emissions at high resolution. The observations acquired by Cassini to date already allow such studies to begin. Simple ballistic projections of high density regions in the solar wind observed at 1 AU have been used successfully to predict the intensification, hence detection, of SKR by Cassini. Also the first high-resolution frequency-time spectrograms of SKR have been acquired; these show a wealth of spectral and temporal structure one would expect on the basis of observations of terrestrial auroral kilometric radiation.

  11. Comparison of Techniques to Reduce Bremsstrahlung Background Radiation from Monoenergetic Photon Beams

    SciTech Connect

    Johnson, M; McNabb, D

    2006-06-29

    An important applied technology is a tunable mono-energetic photon source [1]. These sources are made of relativistic electron accelerators coupled to low-energy lasers, which produce high-energy, mono-energetic-rays. One challenge associated with systems such as this is a continuum of bremsstrahlung background created when an electron beam passes through an aperture of some sort and the electron bunch or its halo impinges on the aperture pictured in figure 1. For instance, in the current T-REX [1] design for the interaction point between the laser- and electron-beam, the electron-beam passes through the center of a mirror used to reflect the laser. There is a potential with this design that bremsstrahlung radiation may be produced at the edges of the mirror openings and contaminate the mono-energetic photon beam. Certain applications [2] may be sensitive to this contamination. To reduce the bremsstrahlung contaminate a collimator (thickness {approx}24in. (calculated from XCOM database [3]) to attenuate by a factor of 10{sup -3} the 112MeV photons expected in the T-REX demonstration [1]) is situated between the aperture and target. To maximize the brightness of the photon-beam, the collimator opening must be no less than the size of the photon-beam spot size expected to be about 1mm. This fixes the collimator opening. a priori the aperture size must be greater than the collimator opening and is a function distance between the aperture and collimator. In this paper we focus on two approaches to estimate the aperture size, given a collimator and a target whose sizes and distances from the aperture are given. In the next section we will discuss these approaches.

  12. Modeling estimates of the effect of acid rain on background radiation dose.

    PubMed

    Sheppard, S C; Sheppard, M I

    1988-06-01

    Acid rain causes accelerated mobilization of many materials in soils. Natural and anthropogenic radionuclides, especially 226Ra and 137Cs, are among these materials. Okamoto is apparently the only researcher to date who has attempted to quantify the effect of acid rain on the "background" radiation dose to man. He estimated an increase in dose by a factor of 1.3 following a decrease in soil pH of 1 unit. We reviewed literature that described the effects of changes in pH on mobility and plant uptake of Ra and Cs. Generally, a decrease in soil pH by 1 unit will increase mobility and plant uptake by factors of 2 to 7. Thus, Okamoto's dose estimate may be too low. We applied several simulation models to confirm Okamoto's ideas, with most emphasis on an atmospherically driven soil model that predicts water and nuclide flow through a soil profile. We modeled a typical, acid-rain sensitive soil using meteorological data from Geraldton, Ontario. The results, within the range of effects on the soil expected from acidification, showed essentially direct proportionality between the mobility of the nuclides and dose. This supports some of the assumptions invoked by Okamoto. We conclude that a decrease in pH of 1 unit may increase the mobility of Ra and Cs by a factor of 2 or more. Our models predict that this will lead to similar increases in plant uptake and radiological dose to man. Although health effects following such a small increase in dose have not been statistically demonstrated, any increase in dose is probably undesirable. PMID:3203639

  13. Modeling estimates of the effect of acid rain on background radiation dose.

    PubMed

    Sheppard, S C; Sheppard, M I

    1988-06-01

    Acid rain causes accelerated mobilization of many materials in soils. Natural and anthropogenic radionuclides, especially 226Ra and 137Cs, are among these materials. Okamoto is apparently the only researcher to date who has attempted to quantify the effect of acid rain on the "background" radiation dose to man. He estimated an increase in dose by a factor of 1.3 following a decrease in soil pH of 1 unit. We reviewed literature that described the effects of changes in pH on mobility and plant uptake of Ra and Cs. Generally, a decrease in soil pH by 1 unit will increase mobility and plant uptake by factors of 2 to 7. Thus, Okamoto's dose estimate may be too low. We applied several simulation models to confirm Okamoto's ideas, with most emphasis on an atmospherically driven soil model that predicts water and nuclide flow through a soil profile. We modeled a typical, acid-rain sensitive soil using meteorological data from Geraldton, Ontario. The results, within the range of effects on the soil expected from acidification, showed essentially direct proportionality between the mobility of the nuclides and dose. This supports some of the assumptions invoked by Okamoto. We conclude that a decrease in pH of 1 unit may increase the mobility of Ra and Cs by a factor of 2 or more. Our models predict that this will lead to similar increases in plant uptake and radiological dose to man. Although health effects following such a small increase in dose have not been statistically demonstrated, any increase in dose is probably undesirable.

  14. Modeling estimates of the effect of acid rain on background radiation dose.

    PubMed Central

    Sheppard, S C; Sheppard, M I

    1988-01-01

    Acid rain causes accelerated mobilization of many materials in soils. Natural and anthropogenic radionuclides, especially 226Ra and 137Cs, are among these materials. Okamoto is apparently the only researcher to date who has attempted to quantify the effect of acid rain on the "background" radiation dose to man. He estimated an increase in dose by a factor of 1.3 following a decrease in soil pH of 1 unit. We reviewed literature that described the effects of changes in pH on mobility and plant uptake of Ra and Cs. Generally, a decrease in soil pH by 1 unit will increase mobility and plant uptake by factors of 2 to 7. Thus, Okamoto's dose estimate may be too low. We applied several simulation models to confirm Okamoto's ideas, with most emphasis on an atmospherically driven soil model that predicts water and nuclide flow through a soil profile. We modeled a typical, acid-rain sensitive soil using meteorological data from Geraldton, Ontario. The results, within the range of effects on the soil expected from acidification, showed essentially direct proportionality between the mobility of the nuclides and dose. This supports some of the assumptions invoked by Okamoto. We conclude that a decrease in pH of 1 unit may increase the mobility of Ra and Cs by a factor of 2 or more. Our models predict that this will lead to similar increases in plant uptake and radiological dose to man. Although health effects following such a small increase in dose have not been statistically demonstrated, any increase in dose is probably undesirable. PMID:3203639

  15. Background Mutational Features of the Radiation-Resistant Bacterium Deinococcus radiodurans

    PubMed Central

    Long, Hongan; Kucukyildirim, Sibel; Sung, Way; Williams, Emily; Lee, Heewook; Ackerman, Matthew; Doak, Thomas G.; Tang, Haixu; Lynch, Michael

    2015-01-01

    Deinococcus bacteria are extremely resistant to radiation, oxidation, and desiccation. Resilience to these factors has been suggested to be due to enhanced damage prevention and repair mechanisms, as well as highly efficient antioxidant protection systems. Here, using mutation-accumulation experiments, we find that the GC-rich Deinococcus radiodurans has an overall background genomic mutation rate similar to that of E. coli, but differs in mutation spectrum, with the A/T to G/C mutation rate (based on a total count of 88 A:T→G:C transitions and 82 A:T→C:G transversions) per site per generation higher than that in the other direction (based on a total count of 157 G:C→A:T transitions and 33 G:C→T:A transversions). We propose that this unique spectrum is shaped mainly by the abundant uracil DNA glycosylases reducing G:C→A:T transitions, adenine methylation elevating A:T→C:G transversions, and absence of cytosine methylation decreasing G:C→A:T transitions. As opposed to the greater than 100× elevation of the mutation rate in MMR− (DNA Mismatch Repair deficient) strains of most other organisms, MMR− D. radiodurans only exhibits a 4-fold elevation, raising the possibility that other DNA repair mechanisms compensate for a relatively low-efficiency DNA MMR pathway. As D. radiodurans has plentiful insertion sequence (IS) elements in the genome and the activities of IS elements are rarely directly explored, we also estimated the insertion (transposition) rate of the IS elements to be 2.50 × 10−3 per genome per generation in the wild-type strain; knocking out MMR did not elevate the IS element insertion rate in this organism. PMID:25976352

  16. Background Mutational Features of the Radiation-Resistant Bacterium Deinococcus radiodurans.

    PubMed

    Long, Hongan; Kucukyildirim, Sibel; Sung, Way; Williams, Emily; Lee, Heewook; Ackerman, Matthew; Doak, Thomas G; Tang, Haixu; Lynch, Michael

    2015-09-01

    Deinococcus bacteria are extremely resistant to radiation, oxidation, and desiccation. Resilience to these factors has been suggested to be due to enhanced damage prevention and repair mechanisms, as well as highly efficient antioxidant protection systems. Here, using mutation-accumulation experiments, we find that the GC-rich Deinococcus radiodurans has an overall background genomic mutation rate similar to that of E. coli, but differs in mutation spectrum, with the A/T to G/C mutation rate (based on a total count of 88 A:T → G:C transitions and 82 A:T → C:G transversions) per site per generation higher than that in the other direction (based on a total count of 157 G:C → A:T transitions and 33 G:C → T:A transversions). We propose that this unique spectrum is shaped mainly by the abundant uracil DNA glycosylases reducing G:C → A:T transitions, adenine methylation elevating A:T → C:G transversions, and absence of cytosine methylation decreasing G:C → A:T transitions. As opposed to the greater than 100× elevation of the mutation rate in MMR(-) (DNA Mismatch Repair deficient) strains of most other organisms, MMR(-) D. radiodurans only exhibits a 4-fold elevation, raising the possibility that other DNA repair mechanisms compensate for a relatively low-efficiency DNA MMR pathway. As D. radiodurans has plentiful insertion sequence (IS) elements in the genome and the activities of IS elements are rarely directly explored, we also estimated the insertion (transposition) rate of the IS elements to be 2.50 × 10(-3) per genome per generation in the wild-type strain; knocking out MMR did not elevate the IS element insertion rate in this organism.

  17. Ultraviolet Radiation and the Photobiology of Earth's Early Oceans

    NASA Astrophysics Data System (ADS)

    Cockell, Charles S.

    2000-10-01

    During the Archean era (3.9-2.5 Ga ago) the earth was dominated by an oceanic lithosphere. Thus, understanding how life arose and persisted in the Archean oceans constitutes a major challenge in understanding early life on earth. Using a radiative transfer model of the late Archean oceans, the photobiological environment of the photic zone and the surface microlayer is explored at the time before the formation of a significant ozone column. DNA damage rates might have been approximately three orders of magnitude higher in the surface layer of the Archean oceans than on the present-day oceans, but at 30 m depth, damage may have been similar to the surface of the present-day oceans. However at this depth the risk of being transported to surface waters in the mixed layer was high. The mixed layer may have been inhabited by a low diversity UV-resistant biota. But it could have been numerically abundant. Repair capabilities similar to Deinococcus radiodurans would be sufficient to survive in the mixed layer. Diversity may have been greater in the region below the mixed layer and above the light compensation point corresponding to today's `deep chlorophyll maximum'. During much of the Archean the air-water interface was probably an uninhabitable extreme environment for neuston. The habitability of some regions of the photic zone is consistent with the evidence embodied in the geologic record, which suggests an oxygenated upper layer in the Archean oceans. During the early Proterozoic, as ozone concentrations increased to a column abundance above 1 × 10^17 cm^-2, UV stress would have been reduced and possibly a greater diversity of organisms could have inhabited the mixed layer. However, nutrient upwelling from newly emergent continental crusts may have been more significant in increasing total planktonic abundance in the open oceans and coastal regions than photobiological factors. The phohobiological environment of the Archean oceans has implications for the potential

  18. Ultraviolet radiation and the photobiology of earth's early oceans.

    PubMed

    Cockell, C S

    2000-10-01

    During the Archean era (3.9-2.5 Ga ago) the earth was dominated by an oceanic lithosphere. Thus, understanding how life arose and persisted in the Archean oceans constitutes a major challenge in understanding early life on earth. Using a radiative transfer model of the late Archean oceans, the photobiological environment of the photic zone and the surface microlayer is explored at the time before the formation of a significant ozone column. DNA damage rates might have been approximately three orders of magnitude higher in the surface layer of the Archean oceans than on the present-day oceans, but at 30 m depth, damage may have been similar to the surface of the present-day oceans. However at this depth the risk of being transported to surface waters in the mixed layer was high. The mixed layer may have been inhabited by a low diversity UV-resistant biota. But it could have been numerically abundant. Repair capabilities similar to Deinococcus radiodurans would be sufficient to survive in the mixed layer. Diversity may have been greater in the region below the mixed layer and above the light compensation point corresponding to today's 'deep chlorophyll maximum'. During much of the Archean the air-water interface was probably an uninhabitable extreme environment for neuston. The habitability of some regions of the photic zone is consistent with the evidence embodied in the geologic record, which suggests an oxygenated upper layer in the Archean oceans. During the early Proterozoic, as ozone concentrations increased to a column abundance above 1 x 10(17) cm-2, UV stress would have been reduced and possibly a greater diversity of organisms could have inhabited the mixed layer. However, nutrient upwelling from newly emergent continental crusts may have been more significant in increasing total planktonic abundance in the open oceans and coastal regions than photobiological factors. The phohobiological environment of the Archean oceans has implications for the potential

  19. Assessment of indoor radiation dose received by the residents of natural high background radiation areas of coastal villages of Kanyakumari district, Tamil Nadu, India

    NASA Astrophysics Data System (ADS)

    Deva Jayanthi, D.; Maniyan, C. G.; Perumal, S.

    2011-07-01

    Radiation exposure and effective dose received through two routes of exposure, viz. external and internal, via inhalation, by residents of 10 villages belonging to Natural High Background Radiation Areas (NHBRA) of coastal regions of Kanyakumari District and Tamil Nadu in India were studied. While the indoor gamma radiation levels were monitored using Thermo Luminescent Dosimeters (TLDs), the indoor radon and thoron gas concentrations were measured using twin chamber dosimeters employing Solid State Nuclear Track Detectors (SSNTDs, LR-115-II). The average total annual effective dose was estimated and found to be varying from 2.59 to 8.76 mSv.

  20. Background Information for Think Tank on Planning, Governance and System Building Early Care and Education--NYC

    ERIC Educational Resources Information Center

    Boressoff, Todd

    2008-01-01

    This document provides some background on early childhood planning and system building around the country. Since mid-December, the author has been studying these efforts for Child Care, Inc. (CCI) interviewing national experts and reading widely. This outline provides insights and lesson learned from those inquiries. The goal at this meeting will…

  1. A Mentor Training Program Improves Mentoring Competency for Researchers Working with Early-Career Investigators from Underrepresented Backgrounds

    ERIC Educational Resources Information Center

    Johnson, Mallory O.; Gandhi, Monica

    2015-01-01

    Mentoring is increasingly recognized as a critical element in supporting successful careers in academic research in medicine and related disciplines, particularly for trainees and early career investigators from underrepresented backgrounds. Mentoring is often executed ad hoc; there are limited programs to train faculty to become more effective…

  2. Gamma radiation induced background determination for (n,γ) measurements with 4π detectors.

    SciTech Connect

    Reifarth, R.; Browne, J. C.; Esch, E. I.; Haight, R. C.; O'Donnell, J. M.; Kronenberg, A.; Rundberg, R. S.; Ullmann, J. L.; Vieira, D. J.; Wilhelmy, J. B.; Wouters, J. M.; Greife, U.

    2003-07-29

    The main focus of this report is to investigate possibilities to disentangle the target originating γ- background from background caused by scattered neutrons at the sample assuming a DANCE like detector to measure detect the capture events.

  3. Translational anisotropy in the cosmic microwave background radiation and far-infrared emission by galactic dust clouds

    NASA Technical Reports Server (NTRS)

    Forman, M. A.

    1977-01-01

    The predicted emission spectrum of galactic dust at about 10 K is compared with the spectrum of 2.8-K universal blackbody radiation and with the spectrum of the anisotropy expected in the 2.8-K radiation due to motion of earth with respect to the coordinate system in which the radiation was last scattered. The extremely anisotropic galactic-dust emission spectrum may contribute a significant background to anisotropy measurements which scan through the galactic plane. The contamination would appear in an 8-mm scan around the celestial equator, for example, as a spurious 200 km/s velocity toward declination 0 deg, right ascension 19 hr, if predictions are correct. The predicted spectrum of dust emission in the galactic plane at longitudes not exceeding about 30 deg falls below the total 2.8-K cosmic background intensity at wavelengths of at least 1 mm.

  4. High-impedance NbSi TES sensors for studying the cosmic microwave background radiation

    NASA Astrophysics Data System (ADS)

    Nones, C.; Marnieros, S.; Benoit, A.; Bergé, L.; Bideaud, A.; Camus, P.; Dumoulin, L.; Monfardini, A.; Rigaut, O.

    2012-12-01

    Precise measurements of the cosmic microwave background (CMB) are crucial in cosmology because any proposed model of the universe must account for the features of this radiation. The CMB has a thermal blackbody spectrum at a temperature of 2.725 K, i.e. the spectrum peaks in the microwave range frequency of 160.2 GHz, corresponding to a 1.9-mm wavelength. Of all CMB measurements that the scientific community has not yet been able to perform, the CMB B-mode polarization is probably the most challenging from the instrumental point of view. The signature of primordial gravitational waves, which give rise to a B-type polarization, is one of the goals in cosmology today and amongst the first objectives in the field. For this purpose, high-performance low-temperature bolometric cameras, made of thousands of pixels, are currently being developed by many groups, which will improve the sensitivity to B-mode CMB polarization by one or two orders of magnitude compared to the Planck satellite HFI detectors. We present here a new bolometer structure that is able to increase the pixel sensitivities and to simplify the fabrication procedure. This innovative device replaces delicate membrane-based structures and eliminates the mediation of phonons: the incoming energy is directly captured and measured in the electron bath of an appropriate sensor and the thermal decoupling is achieved via the intrinsic electron-phonon decoupling of the sensor at very low temperature. Reported results come from a 204-pixel array of NbxSi1-x transition edge sensors with a meander structure fabricated on a 2-inch silicon wafer using electron-beam co-evaporation and a cleanroom lithography process. To validate the application of this device to CMB measurements, we have performed an optical calibration of our sample in the focal plane of a dilution cryostat test bench. We have demonstrated a light absorption close to 20% and an optical noise equivalent power of about 7×10-16 W/√Hz, which is highly

  5. The proportion of childhood leukaemia incidence in Great Britain that may be caused by natural background ionizing radiation.

    PubMed

    Wakeford, R; Kendall, G M; Little, M P

    2009-04-01

    The aetiology of childhood leukaemia remains generally unknown, although exposure to moderate and high levels of ionizing radiation, such as those experienced during the atomic bombings of Japan or from radiotherapy, is an established cause. Risk models based primarily on studies of the Japanese atomic bomb survivors imply that low-level exposure to ionizing radiation, including ubiquitous natural background radiation, also raises the risk of childhood leukaemia. Using two sets of recently published leukaemia risk models and estimates of natural background radiation red-bone-marrow doses received by children, about 20% of the cases of childhood leukaemia in Great Britain are predicted to be attributable to this source. However, for one of these sets of risk models this attributable fraction is materially dependent on how the radiation-induced risk is assumed to be transferred between the Japanese atomic bomb survivors and Western children. Over a range of annual doses representing the range (0.5-2.5 mSv/year) experienced by most populations, the attributable proportion for the preferred risk-transfer model varies between 8 and 30%, with small deviations from a linear relationship that are largely due to the saturation of the model, although again this range of attributable fractions depends on the assumed transfer of risk between populations. PMID:19151785

  6. Population study in the high natural background radiation area in Kerala, India.

    PubMed

    Nair, M K; Nambi, K S; Amma, N S; Gangadharan, P; Jayalekshmi, P; Jayadevan, S; Cherian, V; Reghuram, K N

    1999-12-01

    A comprehensive survey of the population exposed to high-level natural radiation is presented. The population living in Karunagappally taluk in Kerala, India, presents a unique opportunity for studies on the health effects of chronic exposure to low-level radiation. The environmental radiation emanates largely from the thorium deposited mostly along coastal areas. In certain locations on the coast, it is as high as 70 mGy/year and on average is 7.5 times the level seen in interior areas. Using portable scintillometers, radiation levels in more than 66,306 houses were measured; outside levels were also measured in the same house compound. Of the total population of 400,000, 100,000 lived in areas with high natural radiation. Information on lifestyle, socio-demographic features, occupation, housing, residence history, and tobacco and alcohol use was obtained by house-to-house visits and enumeration of every resident individual. A population cancer registry system has been established to obtain cancer incidence rates. In this preliminary analysis, there is no evidence that cancer occurrence is consistently higher because of the levels of external gamma-radiation exposure in the area. Further dosimetry-level studies are needed along with biological studies. Studies of soil, thoron-in-breath, and the radon-thoron levels in houses are ongoing, and further case-control analyses are continuing.

  7. Early corticosteroid administration in experimental radiation-induced heart disease

    SciTech Connect

    Reeves, W.C.; Stryker, J.A.; Abt, A.A.; Chung, C.K.; Whitesell, L.; Zelis, R.

    1980-02-01

    The ability of dexamethasone (DEX) to reduce the severity of the late stage of radiation-induced heart disease (RIHD) was assessed in 25 New Zealand white rabbits. Ten rabbits served as unirradiated controls (CONT). In Group A, seven rabbits received intravenous DEX prior to irradiation and every 24 hours for three consecutive days. DEX was not administered to the eight rabbits in Group B. At 100 days postirradiation, the severity of the late state was determined by microscopic examination (MICRO) for myocardial fibrosis and determination of myocardial hydroxyproline content (MHP). Myocardial fibrosis was evident in groups A (40%) and B (80%) while none was present in CONT by MICRO. One rabbit in Group B with no fibrosis by MICRO had abnormally increased MHP. MHP was significantly increased in Groups A and B, as compared to CONT (p < 0.01). In addition to less fibrosis by MICRO, Group A demonstrated a significant reduction of MHP when compared to Group B (p < 0.05). Determination of MHP may be superior to MICRO in the detection of the late stage of RIHD. Also, early DEX administration appears to reduce myocardial collagen content (fibrosis) in this experimental model.

  8. Triassic origin and early radiation of multicellular volvocine algae

    PubMed Central

    Herron, Matthew D.; Hackett, Jeremiah D.; Aylward, Frank O.; Michod, Richard E.

    2009-01-01

    Evolutionary transitions in individuality (ETIs) underlie the watershed events in the history of life on Earth, including the origins of cells, eukaryotes, plants, animals, and fungi. Each of these events constitutes an increase in the level of complexity, as groups of individuals become individuals in their own right. Among the best-studied ETIs is the origin of multicellularity in the green alga Volvox, a model system for the evolution of multicellularity and cellular differentiation. Since its divergence from unicellular ancestors, Volvox has evolved into a highly integrated multicellular organism with cellular specialization, a complex developmental program, and a high degree of coordination among cells. Remarkably, all of these changes were previously thought to have occurred in the last 50–75 million years. Here we estimate divergence times using a multigene data set with multiple fossil calibrations and use these estimates to infer the times of developmental changes relevant to the evolution of multicellularity. Our results show that Volvox diverged from unicellular ancestors at least 200 million years ago. Two key innovations resulting from an early cycle of cooperation, conflict and conflict mediation led to a rapid integration and radiation of multicellular forms in this group. This is the only ETI for which a detailed timeline has been established, but multilevel selection theory predicts that similar changes must have occurred during other ETIs. PMID:19223580

  9. Computational Assessment of Naturally Occurring Neutron and Photon Background Radiation Produced by Extraterrestrial Sources

    SciTech Connect

    Miller, Thomas Martin; de Wet, Wouter C.; Patton, Bruce W.

    2015-10-28

    In this study, a computational assessment of the variation in terrestrial neutron and photon background from extraterrestrial sources is presented. The motivation of this assessment is to evaluate the practicality of developing a tool or database to estimate background in real time (or near–real time) during an experimental measurement or to even predict the background for future measurements. The extraterrestrial source focused on during this assessment is naturally occurring galactic cosmic rays (GCRs). The MCNP6 transport code was used to perform the computational assessment. However, the GCR source available in MCNP6 was not used. Rather, models developed and maintained by NASA were used to generate the GCR sources. The largest variation in both neutron and photon background spectra was found to be caused by changes in elevation on Earth's surface, which can be as large as an order of magnitude. All other perturbations produced background variations on the order of a factor of 3 or less. The most interesting finding was that ~80% and 50% of terrestrial background neutrons and photons, respectively, are generated by interactions in Earth's surface and other naturally occurring and man-made objects near a detector of particles from extraterrestrial sources and their progeny created in Earth's atmosphere. In conclusion, this assessment shows that it will be difficult to estimate the terrestrial background from extraterrestrial sources without a good understanding of a detector's surroundings. Therefore, estimating or predicting background during a measurement environment like a mobile random search will be difficult.

  10. Real-Time Airborne Gamma-Ray Background Estimation Using NASVD with MLE and Radiation Transport for Calibration

    SciTech Connect

    Kulisek, Jonathan A.; Schweppe, John E.; Stave, Sean C.; Bernacki, Bruce E.; Jordan, David V.; Stewart, Trevor N.; Seifert, Carolyn E.; Kernan, Warnick J.

    2015-06-01

    Helicopter-mounted gamma-ray detectors can provide law enforcement officials the means to quickly and accurately detect, identify, and locate radiological threats over a wide geographical area. The ability to accurately distinguish radiological threat-generated gamma-ray signatures from background gamma radiation in real time is essential in order to realize this potential. This problem is non-trivial, especially in urban environments for which the background may change very rapidly during flight. This exacerbates the challenge of estimating background due to the poor counting statistics inherent in real-time airborne gamma-ray spectroscopy measurements. To address this, we have developed a new technique for real-time estimation of background gamma radiation from aerial measurements. This method is built upon on the noise-adjusted singular value decomposition (NASVD) technique that was previously developed for estimating the potassium (K), uranium (U), and thorium (T) concentrations in soil post-flight. The method can be calibrated using K, U, and T spectra determined from radiation transport simulations along with basis functions, which may be determined empirically by applying maximum likelihood estimation (MLE) to previously measured airborne gamma-ray spectra. The method was applied to both measured and simulated airborne gamma-ray spectra, with and without man-made radiological source injections. Compared to schemes based on simple averaging, this technique was less sensitive to background contamination from the injected man-made sources and may be particularly useful when the gamma-ray background frequently changes during the course of the flight.

  11. The Need for the Quality Improvement Center on Early Childhood: Background Research and Evaluation Framework

    ERIC Educational Resources Information Center

    Center for the Study of Social Policy, 2009

    2009-01-01

    In FY 2009, the Children's Bureau funded the Center for the Study of Social Policy, in partnership with ZERO TO THREE: National Center for Infants, Toddlers, and Families, and the National Alliance of Children's Trust and Prevention Funds, to create a National Quality Improvement Center on Early Childhood (QIC-EC) focused on child maltreatment…

  12. Effects of Teacher Educational Background and Experience on Student Achievement in the Early Grades

    ERIC Educational Resources Information Center

    Leak, James Alexander

    2012-01-01

    This dissertation examines the relationship between teacher educational background, teacher experience, and student achievement in preschool, kindergarten, and first grade. The first essay of this dissertation, "Effects of Teacher Degree Level, Coursework, and Certification on Student Achievement in Math and Reading in Kindergarten,"…

  13. Family Reading Behavior and Early Literacy Skills in Preschool Children from Low-Income Backgrounds

    ERIC Educational Resources Information Center

    Bracken, Stacey Storch; Fischel, Janet E.

    2008-01-01

    This study investigated the family reading behavior of 233 preschool children from low-income backgrounds who were attending Head Start. Parents completed a survey of their family reading behavior, including Child Reading, Parent Reading Interest, and Parent-Child Reading Interaction, and provided demographic data on their educational level,…

  14. Systems and methods for detecting nuclear radiation in the presence of backgrounds

    DOEpatents

    Bross, Alan D.; Mellott, Kerry L.; Pla-Dalmau, Anna

    2005-06-21

    Systems and methods for the simultaneous detection and identification of radiation species, including neutrons, gammas/x-rays and minimum ionizing particles (MIPs). A plurality of rectangular and/or triangularly shaped radiation sensitive scintillators can be configured from a plurality of nano-sized particles, dopants and an extruded plastic material. A wavelength-shifting fiber can then be located within a central hole of each extruded scintillator, wherein the wavelength-shifting fiber absorbs scintillation light and re-emits the light at a longer wavelength, thereby piping the light to a photodetector whose response to the light indicates the presence of radiation The resulting method and system can simultaneously detect neutrons, gamma rays, x-rays and cosmic rays (MIPs) and identify each.

  15. Pulse-shape analysis for gamma background rejection in thermal neutron radiation using CVD diamond detectors

    NASA Astrophysics Data System (ADS)

    Kavrigin, P.; Finocchiaro, P.; Griesmayer, E.; Jericha, E.; Pappalardo, A.; Weiss, C.

    2015-09-01

    A novel technique for the rejection of gamma background from charged-particle spectra was demonstrated using a CVD diamond detector with a 6Li neutron converter installed at a thermal neutron beamline of the TRIGA research reactor at the Atominstitut (Vienna University of Technology). Spectra of the alpha particles and tritons of 6Li(n,T)4He thermal neutron capture reaction were separated from the gamma background by a new algorithm based on pulse-shape analysis. The thermal neutron capture in 6Li is already used for neutron flux monitoring, but the ability to remove gamma background allows using a CVD diamond detector for thermal neutron counting. The pulse-shape analysis can equally be applied to all cases where the charged products of an interaction are absorbed in the diamond and to other background particles that fully traverse the detector.

  16. Computational Assessment of Naturally Occurring Neutron and Photon Background Radiation Produced by Extraterrestrial Sources

    DOE PAGESBeta

    Miller, Thomas Martin; de Wet, Wouter C.; Patton, Bruce W.

    2015-10-28

    In this study, a computational assessment of the variation in terrestrial neutron and photon background from extraterrestrial sources is presented. The motivation of this assessment is to evaluate the practicality of developing a tool or database to estimate background in real time (or near–real time) during an experimental measurement or to even predict the background for future measurements. The extraterrestrial source focused on during this assessment is naturally occurring galactic cosmic rays (GCRs). The MCNP6 transport code was used to perform the computational assessment. However, the GCR source available in MCNP6 was not used. Rather, models developed and maintained bymore » NASA were used to generate the GCR sources. The largest variation in both neutron and photon background spectra was found to be caused by changes in elevation on Earth's surface, which can be as large as an order of magnitude. All other perturbations produced background variations on the order of a factor of 3 or less. The most interesting finding was that ~80% and 50% of terrestrial background neutrons and photons, respectively, are generated by interactions in Earth's surface and other naturally occurring and man-made objects near a detector of particles from extraterrestrial sources and their progeny created in Earth's atmosphere. In conclusion, this assessment shows that it will be difficult to estimate the terrestrial background from extraterrestrial sources without a good understanding of a detector's surroundings. Therefore, estimating or predicting background during a measurement environment like a mobile random search will be difficult.« less

  17. The X-ray log N-log S relation. [background radiation in extragalactic media

    NASA Technical Reports Server (NTRS)

    Boldt, Elihu

    1989-01-01

    Results from various surveys are reviewed as regards X-ray source counts at high galactic latitudes and the luminosity functions determined for extragalactic sources. Constraints on the associated log N-log S relation provided by the extragalactic X-ray background are emphasized in terms of its spatial fluctuations and spectrum as well as absolute flux level. The large number of sources required for this background suggests that there is not a sharp boundary in the redshift distribution of visible matter.

  18. The diffuse far-ultraviolet cosmic background radiation field observed from the Space Shuttle

    NASA Technical Reports Server (NTRS)

    Murthy, J.; Henry, R. C.; Feldman, P. D.; Tennyson, P. D.

    1989-01-01

    The paper presents 17-A resolution spectra of the diffuse far-ultraviolet (1200-1700 A) cosmic background in eight regions of the sky obtained from the Johns Hopkins University UVX experiment aboard the Space Shuttle Columbia (STS-61C) in January 1986. A spectrally flat background is found with brightnesses between 100 and 700 + or - 200 photons/sq cm s sr A, with some evidence for spatial variations, but not for the high-intensity regions found by other experiments.

  19. Anisotropy and polarization of the microwave background radiation as a test of nonequilibrium ionization of the pregalactic plasma

    SciTech Connect

    Nasel'skii, P.D.; Polnarev, A.G.

    1987-11-01

    The formation of small-scale anisotropy and polarization in a model of nonstationary ionization of the pregalactic plasma is considered. It is shown that the ratio of the degree of polarization to the degree of anisotropy is rather insensitive to the actual regime of ionization and is 7-8%. However, the characteristic correlation angle is in the distribution of the anisotropy and polarization of the background radiation on the celestial sphere depends strongly on the parameters of the nonequilibrium.

  20. Accelerated Partial Breast Irradiation Using Only Intraoperative Electron Radiation Therapy in Early Stage Breast Cancer

    SciTech Connect

    Maluta, Sergio; Dall'Oglio, Stefano; Marciai, Nadia; Gabbani, Milena; Franchini, Zeno; Pietrarota, Paolo; Meliado, Gabriele; Guariglia, Stefania; Cavedon, Carlo

    2012-10-01

    Background: We report the results of a single-institution, phase II trial of accelerated partial breast irradiation (APBI) using a single dose of intraoperative electron radiation therapy (IOERT) in patients with low-risk early stage breast cancer. Methods and Materials: A cohort of 226 patients with low-risk, early stage breast cancer were treated with local excision and axillary management (sentinel node biopsy with or without axillary node dissection). After the surgeon temporarily reapproximated the excision cavity, a dose of 21 Gy using IOERT was delivered to the tumor bed, with a margin of 2 cm laterally. Results: With a mean follow-up of 46 months (range, 28-63 months), only 1 case of local recurrence was reported. The observed toxicity was considered acceptable. Conclusions: APBI using a single dose of IOERT can be delivered safely in women with early, low-risk breast cancer in carefully selected patients. A longer follow-up is needed to ascertain its efficacy compared to that of the current standard treatment of whole-breast irradiation.

  1. Fluctuations in microwave background radiation due to secondary ionization of the intergalactic gas in the universe

    NASA Technical Reports Server (NTRS)

    Sunyayev, R. A.

    1979-01-01

    Secondary heating and ionization of the intergalactic gas at redshifts z approximately 10-30 could lead to the large optical depth of the Universe for Thomson scattering and could smooth the primordial fluctuations formed at z approximately 1500. It is shown that the gas motions connected with the large scale density perturbations at z approximately 10-15 must lead to the generation of secondary fluctuations of microwave background. The contribution of the rich clusters of galaxies and young galaxies to the fluctuations of microwave background is also estimated.

  2. Natural radionuclide and radiological assessment of building materials in high background radiation areas of Ramsar, Iran

    PubMed Central

    Bavarnegin, Elham; Moghaddam, Masoud Vahabi; Fathabadi, Nasrin

    2013-01-01

    Building materials, collected from different sites in Ramsar, a northern coastal city in Iran, were analyzed for their natural radionuclide contents. The measurements were carried out using a high resolution high purity Germanium (HPGe) gamma-ray spectrometer system. The activity concentration of 226Ra, 232Th, and 40K content varied from below the minimum detection limit up to 86,400 Bqkg-1, 187 Bqkg-1, and 1350 Bqkg-1, respectively. The radiological hazards incurred from the use of these building materials were estimated through various radiation hazard indices. The result of this survey shows that values obtained for some samples are more than the internationally accepted maximum limits and as such, the use of them as a building material pose significant radiation hazard to individuals. PMID:23776313

  3. First results of the COBE satellite measurement of the anisotropy of the cosmic microwave background radiation

    NASA Technical Reports Server (NTRS)

    Smoot, G. F.; Aymon, J.; De Amici, G.; Bennett, C. L.; Kogut, A.; Gulkis, S.; Backus, C.; Galuk, K.; Jackson, P. D.; Keegstra, P.

    1991-01-01

    The concept and operation of the Differential Microwave Radiometers (DMR) instrument aboard NASA's Cosmic Background Explorer satellite are reviewed, with emphasis on the software identification and subtraction of potential systematic effects. Preliminary results obtained from the first six months of DMR data are presented, and implications for cosmology are discussed.

  4. The modulating impact of illumination and background radiation on 8 Hz-induced infrasound effect on physicochemical properties of physiolagical solution.

    PubMed

    Baghdasaryan, Naira; Mikayelyan, Yerazik; Barseghyan, Sedrak; Dadasyan, Erna; Ayrapetyan, Sinerik

    2012-12-01

    At present, when the level of background ionizing radiation is increasing in a number of world locations, the problem of the study of biological effect of high background radiation becomes one of the extremely important global problems in modern life sciences. The modern research in biophysics proved that water is a most essential target, through which the biological effects of ionizing and non-ionizing radiations are realized. Therefore, there is no doubt about the strong dependency of non-ionizing radiation-induced effect on the level of background radiation. Findings have shown that illumination and background radiation have a strong modulation effect on infrasound-induced impacts on water physicochemical properties, which could also have appropriate effect on living organisms. PMID:22676714

  5. Implications of the cosmic microwave background power asymmetry for the early universe

    NASA Astrophysics Data System (ADS)

    Byrnes, Christian T.; Regan, Donough; Seery, David; Tarrant, Ewan R. M.

    2016-06-01

    Observations of the microwave background fluctuations suggest a scale-dependent amplitude asymmetry of roughly 2.5 σ significance. Inflationary explanations for this "anomaly" require non-Gaussian fluctuations which couple observable modes to those on much larger scales. In this paper, we describe an analysis of such scenarios which significantly extends previous treatments. We identify the non-Gaussian "response function" which characterizes the asymmetry and show that it is nontrivial to construct a model which yields a sufficient amplitude; many independent fine-tunings are required, often making such models appear less likely than the anomaly they seek to explain. We present an explicit model satisfying observational constraints and determine for the first time how large its bispectrum would appear to a Planck-like experiment. Although this model is merely illustrative, we expect it is a good proxy for the bispectrum in a sizeable class of models which generate a scale-dependent response using a large η parameter.

  6. The Sail-Backed Reptile Ctenosauriscus from the Latest Early Triassic of Germany and the Timing and Biogeography of the Early Archosaur Radiation

    PubMed Central

    Butler, Richard J.; Brusatte, Stephen L.; Reich, Mike; Nesbitt, Sterling J.; Schoch, Rainer R.; Hornung, Jahn J.

    2011-01-01

    Background Archosaurs (birds, crocodilians and their extinct relatives including dinosaurs) dominated Mesozoic continental ecosystems from the Late Triassic onwards, and still form a major component of modern ecosystems (>10,000 species). The earliest diverse archosaur faunal assemblages are known from the Middle Triassic (c. 244 Ma), implying that the archosaur radiation began in the Early Triassic (252.3–247.2 Ma). Understanding of this radiation is currently limited by the poor early fossil record of the group in terms of skeletal remains. Methodology/Principal Findings We redescribe the anatomy and stratigraphic position of the type specimen of Ctenosauriscus koeneni (Huene), a sail-backed reptile from the Early Triassic (late Olenekian) Solling Formation of northern Germany that potentially represents the oldest known archosaur. We critically discuss previous biomechanical work on the ‘sail’ of Ctenosauriscus, which is formed by a series of elongated neural spines. In addition, we describe Ctenosauriscus-like postcranial material from the earliest Middle Triassic (early Anisian) Röt Formation of Waldhaus, southwestern Germany. Finally, we review the spatial and temporal distribution of the earliest archosaur fossils and their implications for understanding the dynamics of the archosaur radiation. Conclusions/Significance Comprehensive numerical phylogenetic analyses demonstrate that both Ctenosauriscus and the Waldhaus taxon are members of a monophyletic grouping of poposauroid archosaurs, Ctenosauriscidae, characterised by greatly elongated neural spines in the posterior cervical to anterior caudal vertebrae. The earliest archosaurs, including Ctenosauriscus, appear in the body fossil record just prior to the Olenekian/Anisian boundary (c. 248 Ma), less than 5 million years after the Permian–Triassic mass extinction. These earliest archosaur assemblages are dominated by ctenosauriscids, which were broadly distributed across northern Pangea and which

  7. Chromosome aberration, cancer mortality and hormetic phenomena among inhabitants in areas of high background radiation in China.

    PubMed

    Chen, D; Wei, L

    1991-12-01

    The respective average annual doses are about 330 and 110 mR/yr, in the high background radiation areas (HBRA) in Yangjiang County and the control areas (CA) in Enping and Taishan Counties. Both the HBRA and CA are in Guangdong Province which borders the South China Sea. The frequencies of chromosome aberration in circulating lymphocytes were examined for persons residing in the HBRA and CA. Those in the HBRA had increased frequencies of detectable abnormalities in stable aberrations (translocations and inversions) and unstable aberrations (dicentrics and rings). Previous reports have shown that when samples of circulating lymphocytes taken from inhabitants were tested in vitro for mitotic responses to phytohemagglutinin (PHA) and for the degree of unscheduled DNA synthesis (UDS) induced by UV-irradiation, there were higher responsiveness and UDS rates for those in the HBRA than in the CA. In contrast, mortality from all cancers and those from leukemia, breast and lung cancers that are inducible by radiation was not higher in the HBRA. Although the differences in the cancer mortality rates for the HBRA and CA are not significant, the findings are compatible with the assumption that the lower mortality from cancer in the HBRA is the result of the hormetic effects of the three-fold higher dose rate of background radiation in that areas. This assumption requires further study.

  8. Small-scale primordial magnetic fields and anisotropies in the cosmic microwave background radiation

    SciTech Connect

    Jedamzik, Karsten; Abel, Tom E-mail: tabel@slac.stanford.edu

    2013-10-01

    It is shown that small-scale magnetic fields present before recombination induce baryonic density inhomogeneities of appreciable magnitude. The presence of such inhomogeneities changes the ionization history of the Universe, which in turn decreases the angular scale of the Doppler peaks and increases Silk damping by photon diffusion. This unique signature could be used to (dis)prove the existence of primordial magnetic fields of strength as small as B ≅ 10{sup −11} Gauss by cosmic microwave background observations.

  9. Before the Microwave Background: Early Big Bang Cosmology (The J. Robert Oppenheimer Lecture)

    NASA Astrophysics Data System (ADS)

    Kragh, Helge

    2006-04-01

    Finite-age (or big-bang) cosmological models can be traced back to G. Lemaître's relativistic model of 1931 (or even earlier, to A. Friedmann in 1922). However, the big bang concept does not exclusively belong to the class of relativistic models, and in the 1930s it was often associated with E.A. Milne's very different, so-called kinematic cosmology. But it was only with G. Gamow's research program in the late 1940s that the big-bang scenario became widely known and turned into a nuclear-physical theory of the early universe. How does the theory of Gamow and his collaborators R. Alpher and R. Herman compare with Lemaître's earlier ideas of a ``primeval atom''? And with the post-1965 version of big bang cosmology? The strange fate of the Gamow-Alpher-Herman hot big bang theory can only be understood if taking into account that relativistic evolution cosmology faced stiff competition throughout the 1950s from the steady-state theory of F. Hoyle and others.

  10. Radon Monitoring and Early Low Background Counting at the Sanford Underground Laboratory

    SciTech Connect

    Thomas, K. J.; Mei, D.-M.; Heise, J.; Durben, D.; Salve, R.

    2011-04-27

    Radon detectors have been deployed underground at the Sanford Underground Laboratory at the site of the former Homestake Mine in Lead, SD. Currently, no radon mitigation measures are in place in the underground environment, and the continuing evolution of the facility ventilation systems has led to significant variations in early airborne radon concentrations. The average radon concentration measured near the primary ventilation intake for the 4850-ft level (Yates shaft) is 391 Bq/m{sup 3}, based on approximately 146 days of data. The corresponding average radon concentration near the other main ventilation intake for the 4850-ft level (Ross shaft) is 440 Bq/m{sup 3} based on approximately 350 days of data. Measurements have also been collected near the 1250-ft level Ross shaft, with average radon concentrations at 180 Bq/m{sup 3}. Secondary factors that may increase the baseline radon level underground include the presence of iron oxide and moisture, which are known to enhance radon emanation. The results of the current radon monitoring program will be used for the planning of future measurements and any potential optimization of ventilation parameters for the reduction of radon in relevant areas underground.

  11. Dynamics of rye telomeres in a wheat background during early meiosis.

    PubMed

    Naranjo, Tomás

    2014-01-01

    Migration of the telomere of the short arm of rye chromosome 5R (5RS) during bouquet organization is dependent on the conformation that this chromosome adopts in its intact, submetacentric, or truncated, metacentric, form. In order to establish whether the telomere migration dependence on chromosome conformation is a common feature of all rye chromosomes, the behavior of the telomeres of 2 other rye chromosomes, 1R and 6R, with apparent differences in the arm ratio, has been studied at the bouquet stage and compared with that of 5R. The presence of subtelomeric heterochromatic chromomeres in both arms of 1R and 6R, which were visualized by FISH, revealed the position of the adjacent telomeres in the bouquet. While the end of the long arms of both chromosomes was, with some exceptions, always included in the telomere cluster, the end of the short arms failed to migrate to the telomere pole. Disturbed telomere migration was more often observed in the short arm of the submetacentric chromosome 6R than in the short arm of the almost metacentric chromosome 1R. Thus, the chromosomal conformation effect on telomere mobility is a common feature of all rye chromosomes. Incomplete telomere clustering is followed by failure of synapsis and chiasma formation in chromosomes 5R and 6R. Chromosome arm 1RS, which carries the NOR, completes synapsis earlier than 5RS or 6RS, facilitated by the nucleolar fusion that occurs during early zygotene. PMID:24969495

  12. Familial early-onset dementia with complex neuropathologic phenotype and genomic background.

    PubMed

    Alexander, John; Kalev, Ognian; Mehrabian, Shima; Traykov, Latchezar; Raycheva, Margariata; Kanakis, Dimitrios; Drineas, Petros; Lutz, Mirjam I; Ströbel, Thomas; Penz, Thomas; Schuster, Michael; Bock, Christoph; Ferrer, Isidro; Paschou, Peristera; Kovacs, Gabor G

    2016-06-01

    Despite significant progress in our understanding of hereditary neurodegenerative diseases, the list of genes associated with early-onset dementia is not yet complete. In the present study, we describe a familial neurodegenerative disorder characterized clinically as the behavioral and/or dysexecutive variant of Alzheimer's disease with neuroradiologic features of Alzheimer's disease, however, lacking amyloid-β deposits in the brain. Instead, we observed a complex, 4 repeat predominant, tauopathy, together with a TAR DNA-binding protein of 43 kDa proteinopathy. Whole-exome sequencing on 2 affected siblings and 1 unaffected aunt uncovered a large number of candidate genes, including LRRK2 and SYNE2. In addition, DDI1, KRBA1, and TOR1A genes possessed novel stop-gain mutations only in the patients. Pathway, gene ontology, and network interaction analysis indicated the involvement of pathways related to neurodegeneration but revealed novel aspects also. This condition does not fit into any well-characterized category of neurodegenerative disorders. Exome sequencing did not disclose a single disease-specific gene mutation suggesting that a set of genes working together in different pathways may contribute to the etiology of the complex phenotype. PMID:27143436

  13. Radon monitoring and early low background counting at the Sanford Underground Laboratory

    SciTech Connect

    Thomas, K.J.; Mei, D.M.; Heise, J.; Durben, D.; Salve, R.

    2010-09-01

    Radon detectors have been deployed underground at the Sanford Underground Laboratory at the site of the former Homestake Mine in Lead, SD. Currently, no radon mitigation measures are in place in the underground environment, and the continuing evolution of the facility ventilation systems has led to significant variations in early airborne radon concentrations. The average radon concentration measured near the primary ventilation intake for the 4850-ft level (Yates shaft) is 391 Bq/m{sup 3}, based on approximately 146 days of data. The corresponding average radon concentration near the other main ventilation intake for the 4850-ft level (Ross shaft) is 440 Bq/m{sup 3} based on approximately 350 days of data. Measurements have also been collected near the 1250-ft level Ross shaft, with average radon concentrations at 180 Bq/m{sup 3}. Secondary factors that may increase the baseline radon level underground include the presence of iron oxide and moisture, which are known to enhance radon emanation. The results of the current radon monitoring program will be used for the planning of future measurements and any potential optimization of ventilation parameters for the reduction of radon in relevant areas underground.

  14. The impact of family background and early marital factors on marital disruption.

    PubMed

    Bumpass, L L; Martin, T C; Sweet, J A

    1991-03-01

    Data from the National Survey of Families and Households for 1987-1988 are used to explore methodological and substantive issues concerning marital dissolution in the United States. "The analysis finds that marital disruptions are seriously underreported by males, making the analysis of male marital histories problematic. Also, the potential impact of reconciliations on the estimates of recent marital disruption based on separation is explored; no upward bias is likely to result from the inclusion of separations that may subsequently reconcile. The impact of a wide variety of factors on the risk of marital disruption is examined using proportional hazard techniques. Among them are included parental background factors, respondent's characteristics at the time of marriage, differences in spouses' characteristics, and joint activity statuses of marital partners in the first year of marriage. The risk of marital disruption is highest among women with young age at marriage, low education, a cohabitation history, and those whose spouse has been married previously. Parental family disruption affects marital stability primarily through age at marriage and cohabitation. Religious and educational heterogamy and male unemployment reduce marital stability."

  15. An ultraviolet-radiation-independent pathway to melanoma carcinogenesis in the red hair/fair skin background.

    PubMed

    Mitra, Devarati; Luo, Xi; Morgan, Ann; Wang, Jin; Hoang, Mai P; Lo, Jennifer; Guerrero, Candace R; Lennerz, Jochen K; Mihm, Martin C; Wargo, Jennifer A; Robinson, Kathleen C; Devi, Suprabha P; Vanover, Jillian C; D'Orazio, John A; McMahon, Martin; Bosenberg, Marcus W; Haigis, Kevin M; Haber, Daniel A; Wang, Yinsheng; Fisher, David E

    2012-11-15

    People with pale skin, red hair, freckles and an inability to tan--the 'red hair/fair skin' phenotype--are at highest risk of developing melanoma, compared to all other pigmentation types. Genetically, this phenotype is frequently the product of inactivating polymorphisms in the melanocortin 1 receptor (MC1R) gene. MC1R encodes a cyclic AMP-stimulating G-protein-coupled receptor that controls pigment production. Minimal receptor activity, as in red hair/fair skin polymorphisms, produces the red/yellow pheomelanin pigment, whereas increasing MC1R activity stimulates the production of black/brown eumelanin. Pheomelanin has weak shielding capacity against ultraviolet radiation relative to eumelanin, and has been shown to amplify ultraviolet-A-induced reactive oxygen species. Several observations, however, complicate the assumption that melanoma risk is completely ultraviolet-radiation-dependent. For example, unlike non-melanoma skin cancers, melanoma is not restricted to sun-exposed skin and ultraviolet radiation signature mutations are infrequently oncogenic drivers. Although linkage of melanoma risk to ultraviolet radiation exposure is beyond doubt, ultraviolet-radiation-independent events are likely to have a significant role. Here we introduce a conditional, melanocyte-targeted allele of the most common melanoma oncoprotein, BRAF(V600E), into mice carrying an inactivating mutation in the Mc1r gene (these mice have a phenotype analogous to red hair/fair skin humans). We observed a high incidence of invasive melanomas without providing additional gene aberrations or ultraviolet radiation exposure. To investigate the mechanism of ultraviolet-radiation-independent carcinogenesis, we introduced an albino allele, which ablates all pigment production on the Mc1r(e/e) background. Selective absence of pheomelanin synthesis was protective against melanoma development. In addition, normal Mc1r(e/e) mouse skin was found to have significantly greater oxidative DNA and lipid

  16. Probing the Cosmic X-Ray and MeV Gamma-Ray Background Radiation through the Anisotropy

    SciTech Connect

    Inoue, Yoshiyuki; Murase, Kohta; Madejski, Grzegorz M.; Uchiyama, Yasunobu

    2013-09-24

    While the cosmic soft X-ray background is very likely to originate from individual Seyfert galaxies, the origin of the cosmic hard X-ray and MeV gamma-ray background is not fully understood. It is expected that Seyferts including Compton thick population may explain the cosmic hard X-ray background. At MeV energy range, Seyferts having non-thermal electrons in coronae above accretion disks or MeV blazars may explain the background radiation. We propose that future measurements of the angular power spectra of anisotropy of the cosmic X-ray and MeV gamma-ray backgrounds will be key to deciphering these backgrounds and the evolution of active galactic nuclei (AGNs). As AGNs trace the cosmic large-scale structure, spatial clustering of AGNs exists. We show that e-ROSITA will clearly detect the correlation signal of unresolved Seyferts at 0.5-2 keV and 2-10 keV bands and will be able to measure the bias parameter of AGNs at both bands. Once the future hard X-ray all sky satellites achieve the sensitivity better than 10-12 erg/cm2/s-1 at 10-30 keV or 30-50 keV - although this is beyond the sensitivities of current hard X-ray all sky monitors - angular power spectra will allow us to independently investigate the fraction of Compton-thick AGNs in all Seyferts. We also find that the expected angular power spectra of Seyferts and blazars in the MeV range are different by about an order of magnitude, where the Poisson term, so-called shot noise, is dominant. Current and future MeV instruments will clearly disentangle the origin of the MeV gamma-ray background through the angular power spectrum.

  17. Electron magnetic moment from geonium spectra: Early experiments and background concepts

    NASA Astrophysics Data System (ADS)

    van Dyck, Robert S., Jr.; Schwinberg, Paul B.; Dehmelt, Hans G.

    1986-08-01

    The magnetic moment of a free electron has been measured by observing both its low-energy spin and cyclotron resonances (at νs=ωs/2π and νc=ωc/2π, respectively) by means of a sensitive frequency-shift technique. Using radiation and tuned-circuit damping of a single electron, isolated in a special anharmonicity-compensated Penning trap, also cooled to 4 K, the electron's motion is brought nearly to rest, thus preparing it in a cold quasipermanent state of the geonium ``atom.'' The magnetic-coupling scheme, described as a continuous Stern-Gerlach effect, is made possible through a weak Lawrence magnetic bottle which causes the very narrow axial resonance, at νz=ωz/2π for the harmonically bound electron, to change in frequency by a small fixed amount δ per unit change in magnetic quantum number. Spin flips are indirectly induced by a scheme which weakly drives the axial motion at the νa=ωa/2π spin-cyclotron difference frequency within the inhomogeneous magnetic field, thus yielding a measure of ωa≡ωs-ωc. The magnetic moment μs in terms of the Bohr magneton μB equals (1/2) the spin's g factor, which in turn is described by ωs and ωc: g=2μs/μB=2ωs/ωc. In a Penning trap, however, these resonance frequencies are obtained from the observed cyclotron frequency at ω'c=ωc-δe and the observed anomaly frequency at ω'a=ωs-ω'c, which are related by the small electric shift δe computed using the measured axial frequency and 2δeω'c=ωz 2. This last expression, derived for a perfectly axially symmetric trap, happens to be practically invariant against small imperfections in the electric quadrupole field (error in ωc<10-16). The magnetic-bottle-determined line shapes are analyzed and found to have sharp low-frequency edge features which correspond to the electron being temporarily at the trap center and at the bottom of the magnetic well. Relativistic shifts are considered and found to be <10-11. Our result at the time of submission, g/2=1.001 159

  18. Late Effects May Not Warrant Using Radiation to Treat Early-Stage Hodgkin Lymphoma

    Cancer.gov

    Patients with early-stage Hodgkin lymphoma who were treated with multidrug chemotherapy alone were more likely to be alive 12 years later than patients who received treatment that included radiation therapy, according to findings from a clinical trial.

  19. Solar modulation of the neutron component of the radiation background observed simultaneously in different space missions

    NASA Astrophysics Data System (ADS)

    Litvak, Maxim; Mitrofanov, Igor; Nuzhdin, Igor; Sanin, Anton; Fedosov, Fedor; Golovin, Dmitry

    2016-04-01

    We have studied variability of neutron component of radiation environment at Earth, Moon and Mars vicinities over a long period of time produced by the solar modulation of the GCR flux in the 23rd and 24th solar cycles. The global behavior of the neutron flux is in relatively good agreement with different observations performed simultaneously onboard various space missions, including instruments HEND onboard Mars Odyssey orbiter, BTN onboard International Space Station and LEND onboard Lunar Reconnaissance Orbiter as well as with the modeled behavior of the GCR flux derived from a global network of neutron monitors on the Earth. The local differences in the time history and character of different observations have been also evaluated. The joint analysis of different data sets, where some of them are gathered far away from the Earth, reveals a multi-dimensional view and new patterns of the solar modulation of GCRs within current unusual solar cycle.

  20. Reduction of Radioactive Backgrounds in Electroformed Copper for Ultra-Sensitive Radiation Detectors

    SciTech Connect

    Hoppe, Eric W.; Aalseth, Craig E.; Farmer, Orville T.; Hossbach, Todd W.; Liezers, Martin; Miley, Harry S.; Overman, Nicole R.; Reeves, James H.

    2014-07-07

    Abstract Ultra-pure construction materials are required for the next generation of neutrino physics, dark matter and environmental science applications. These new efforts require materials with purity levels at or below 1 uBq/kg 232Th and 238U. Yet radiometric analysis lacks sensitivity below ~10 uBq/kg for the U and Th decay chains. This limits both the selection of clean materials and the validation of purification processes. Copper is an important high-purity material for low-background experiments due to the ease with which it can be purified by electrochemical methods. Electroplating for purification into near-final shapes, known as electroforming, is one such method. Continued refinement of the copper electroforming process is underway, for the first time guided by an ICP-MS based assay method that can measure 232Th and 238U near the desired purity levels. An assay of electroformed copper at 10 uBq/kg for 232Th has been achieved and is described. The implications of electroformed copper at or better than this purity on next-generation low-background experiments are discussed.

  1. The Temperature of the Cosmic Background Radiation: Results fromthe 1987 and 1988 Measurements at 3.8 GHz

    SciTech Connect

    De Amici, Giovanni; Bensadoun, M.; Bersanelli, M.; Kogut, A.; Levine, S.; Smoot, George F.; Witebsky, C.

    1989-11-10

    We have measured the temperature of the cosmic background radiation (CBR) at a frequency of 3.8 GHz (7.9 cm wavelength), during two consecutive summers, obtaining a brightness temperature, T{sub CBR}, of 2.56 {+-} 0.08 K in 1987 and 2.71 {+-} 0.07 K in 1988 (68% confidence level). The new results are in agreement with our previous measurement at 3.7 GHz obtained in 1986, and have smaller error bars. Combining measurements from all three years we obtain T{sub CBR} = 2.64 {+-} 0.07 K.

  2. A bolometric millimeter-wave system for observations of anisotropy in the cosmic microwave background radiation on medium angular scales

    NASA Technical Reports Server (NTRS)

    Fischer, M. L.; Alsop, D. C.; Cheng, E. S.; Clapp, A. C.; Cottingham, D. A.; Gundersen, J. O.; Koch, T. C.; Kreysa, E.; Meinhold, P. R.; Lange, A. E.

    1992-01-01

    The performance of a bolometric system designed to measure the anisotropy of the cosmic microwave background (CMB) radiation on angular scales from 0.3 to 3 deg is presented. The system represents a collaborative effort combining a low-background 1-m diameter balloon-borne telescope with new multimode feed optics, a beam modulation mechanism with high stability, and a four-channel bolometric receiver with passbands centered near frequencies of 3, 6, 9, and 12/cm (90, 180, 270, and 360 GHz). The telescope has been flown three times with the bolometric receiver and has demonstrated detector noise limited performance capable of reaching sensitivity levels of about 0.00001 with detectors operated at 0.3 K.

  3. A bolometric millimeter-wave system for observations of anisotropy in the cosmic microwave background radiation on medium angular scales

    NASA Technical Reports Server (NTRS)

    Fischer, M. L.; Alsop, D. C.; Cheng, E. S.; Clapp, A. C.; Cottingham, D. A.; Gundersen, J. O.; Koch, T. C.; Kreysa, E.; Meinhold, P. R.; Lange, A. E.

    1992-01-01

    We report the performance of a bolometric system designed to measure the anisotropy of the cosmic microwave background (CMB) radiation on angular scales from 0 deg 3 min to 3 deg. The system represents a collaborative effort combining a low-background 1 m diameter balloon-borne telescope with new multimode feed optics, a beam modulation mechanism with high stability, and a four-channel bolometric receiver with passbands centered near frequencies of 3 (90), 6 (180), 9 (270), and 12 (360) cm(exp -1) (GHz). The telescope was flown three times with the bolometric receiver and has demonstrated detector noise limited performance capable of reaching sensitivity levels of Delta(T)/T(sub CMB) is approximately equal to 10(exp -5) with detectors operated at T = 0.3 K.

  4. Understanding the Early Evolution of M dwarf Extreme Ultraviolet Radiation

    NASA Astrophysics Data System (ADS)

    Peacock, Sarah; Barman, Travis; Shkolnik, Evgenya

    2015-11-01

    The chemistry and evolution of planetary atmospheres depends on the evolution of high-energy radiation emitted by its host star. High levels of extreme ultraviolet (EUV) radiation can drastically alter the atmospheres of terrestrial planets through ionizing, heating, expanding, chemically modifying and eroding them during the first few billion years of a planetary lifetime. While there is evidence that stars emit their highest levels of far and near ultraviolet (FUV; NUV) radiation in the earliest stages of their evolution, we are currently unable to directly measure the EUV radiation. Most previous stellar atmosphere models under-predict FUV and EUV emission from M dwarfs; here we present new models for M stars that include prescriptions for the hot, lowest density atmospheric layers (chromosphere, transition region and corona), from which this radiation is emitted. By comparing our model spectra to GALEX near and far ultraviolet fluxes, we are able to predict the evolution of EUV radiation for M dwarfs from 10 Myr to a few Gyr. This research is the next major step in the HAZMAT (HAbitable Zones and M dwarf Activity across Time) project to analyze how the habitable zone evolves with the evolving properties of stellar and planetary atmospheres.

  5. Isotropic blackbody cosmic microwave background radiation as evidence for a homogeneous universe.

    PubMed

    Clifton, Timothy; Clarkson, Chris; Bull, Philip

    2012-08-01

    The question of whether the Universe is spatially homogeneous and isotropic on the largest scales is of fundamental importance to cosmology but has not yet been answered decisively. Surprisingly, neither an isotropic primary cosmic microwave background (CMB) nor combined observations of luminosity distances and galaxy number counts are sufficient to establish such a result. The inclusion of the Sunyaev-Zel'dovich effect in CMB observations, however, dramatically improves this situation. We show that even a solitary observer who sees an isotropic blackbody CMB can conclude that the Universe is homogeneous and isotropic in their causal past when the Sunyaev-Zel'dovich effect is present. Critically, however, the CMB must either be viewed for an extended period of time, or CMB photons that have scattered more than once must be detected. This result provides a theoretical underpinning for testing the cosmological principle with observations of the CMB alone.

  6. Interpretation of the cosmic microwave background radiation anisotropy detected by the COBE Differential Microwave Radiometer

    NASA Technical Reports Server (NTRS)

    Wright, E. L.; Meyer, S. S.; Bennett, C. L.; Boggess, N. W.; Cheng, E. S.; Hauser, M. G.; Kogut, A.; Lineweaver, C.; Mather, J. C.; Smoot, G. F.

    1992-01-01

    The large-scale cosmic background anisotropy detected by the COBE Differential Microwave Radiometer (DMR) instrument is compared to the sensitive previous measurements on various angular scales, and to the predictions of a wide variety of models of structure formation driven by gravitational instability. The observed anisotropy is consistent with all previously measured upper limits and with a number of dynamical models of structure formation. For example, the data agree with an unbiased cold dark matter (CDM) model with H0 = 50 km/s Mpc and Delta-M/M = 1 in a 16 Mpc radius sphere. Other models, such as CDM plus massive neutrinos (hot dark matter (HDM)), or CDM with a nonzero cosmological constant are also consistent with the COBE detection and can provide the extra power seen on 5-10,000 km/s scales.

  7. Background Radiation Survey of the Radiological/Nuclear Countermeasures Test and Evaluation Center

    SciTech Connect

    Colin Okada

    2010-09-16

    In preparation for operations at the Radiological/Nuclear Countermeasures Test and Evaluation Complex (Rad/NucCTEC), the Department of Homeland Security Domestic Nuclear Detection Office (DHS/DNDO) requested that personnel from the Remote Sensing Laboratory (RSL) conduct a survey of the present radiological conditions at the facility. The measurements consist of the exposure rate from a high-pressure ion chamber (HPIC), high-resolution spectra from a high-purity germanium (HPGe) system in an in situ configuration, and low-resolution spectra from a sodium iodide (NaI) detector in a radiation detection backpack. Measurements with these systems were collected at discrete locations within the facility. Measurements were also collected by carrying the VECTOR backpack throughout the complex to generate a map of the entire area. The area was also to be surveyed with the Kiwi (an array of eight-2-inch x 4-inch x 16-inch NaI detectors) from the Aerial Measuring Systems; however, conflicts with test preparation activities at the site prevented this from being accomplished.

  8. The cosmic background explorer

    SciTech Connect

    Gulkis, G. ); Lubin, P.M. ); Meyer, S.S. ); Silverberg, R.F.

    1990-01-01

    Late last year the National Aeronautics and Space Administration launched its first satellite dedicated to the study of phenomena related to the origins of the universe. The satellite, called the Cosmic Background Explorer (COBE), carries three complementary detectors that will make fundamental measurements of the celestial radiation. Part of that radiation is believed to have originated in processes that occurred at the very dawn of the universe. By measuring the remnant radiation at wavelengths from one micrometer to one centimeter across the entire sky, scientists hope to be able to solve many mysteries regarding the origin and evolution of the early universe. Unfortunately, these radiative relics of the early universe are weak and veiled by local astrophysical and terrestrial sources of radiation. The wavelengths of the various cosmic components may also overlap, thereby making the understanding of the diffuse celestial radiation a challenge. Nevertheless, the COBE instruments, with their full-sky coverage, high sensitivity to a wide range of wavelengths and freedom from interference from the earth's atmosphere, will constitute for astrophysicists an observatory of unprecedented sensitivity and scope. The interesting cosmic signals will then be separated from one another and from noncosmic radiation sources by a comprehensive analysis of the data.

  9. AID, p53 and MLH1 expression in early gastric neoplasms and the correlation with the background mucosa

    PubMed Central

    KAWATA, SOICHIRO; YASHIMA, KAZUO; YAMAMOTO, SOHEI; SASAKI, SHUJI; TAKEDA, YOHEI; HAYASHI, AKIHIRO; MATSUMOTO, KAZUYA; KAWAGUCHI, KOICHIRO; HARADA, KENICHI; MURAWAKI, YOSHIKAZU

    2015-01-01

    A number of tumor-associated genes have been associated with gastric cancer development. The present study evaluated differences in tumor-associated protein expression and phenotype among early gastric neoplasms, and correlated these data with those of the background mucosa. The expression of activation-induced cytidine deaminase (AID), p53 and MLH1 in 151 early gastric neoplasms [22 gastric adenomas, 92 intramucosal carcinomas (MCs), and 37 submucosal carcinomas (SMCs)] was examined immunohistochemically and compared with that of the corresponding background mucosal condition. The cellular phenotypes of the neoplasms and the corresponding background intestinal metaplasia were also determined. Aberrant AID, p53 and MLH1 expression was detected in 36.4, 0 and 0% of the adenomas, in 35.9, 32.6 and 16.3% of the MCs, and in 56.8, 62.2 and 21.6% of the SMCs, respectively. The frequency of aberrant AID and p53 expression in the SMCs was significantly increased compared with that in the MCs (AID, P<0.05; p53, P<0.01). Aberrant AID expression was significantly associated with p53 overexpression in the SMCs (P<0.01), but not in the adenomas or MCs. In addition, AID expression was associated with the severity of mononuclear cell activity in the non-cancerous mucosa adjacent to the tumor (P<0.05), particularly in the SMC cases. The percentage of MCs (34.8%) and SMCs (24.3%) that were of the gastric phenotype was higher compared with the percentage of adenomas (18.2%). These results indicated that p53 and MLH1 expression and a gastric phenotype may be important for carcinogenesis, and that chronic inflammation and AID and p53 expression are associated with submucosal progression. PMID:26622562

  10. A possible cold imprint of voids on the microwave background radiation

    SciTech Connect

    Cai, Yan-Chuan; Cole, Shaun; Frenk, Carlos S.; Neyrinck, Mark C.; Szapudi, István

    2014-05-10

    We measure the average temperature decrement on the cosmic microwave background (CMB) produced by voids selected in the Sloan Digital Sky Survey Data Release 7 spectroscopic redshift galaxy catalog, spanning redshifts 0 < z < 0.44. We find an imprint amplitude between 2.6 and 2.9 μK as viewed through a compensated top-hat filter scaled to the radius of each void, we assess the statistical significance of the imprint at ∼2σ, and we make crucial use of N-body simulations to calibrate our analysis. As expected, we find that large voids produce cold spots on the CMB through the integrated Sachs-Wolfe (ISW) effect. However, we also find that small voids in the halo density field produce hot spots, because they reside in contracting, larger-scale overdense regions. This is an important effect to consider when stacking CMB imprints from voids of different radii. We have found that the same filter radius that gives the largest ISW signal in simulations also yields close to the largest detected signal in the observations. However, although it is low in significance, our measured signal has a much higher amplitude than expected from ISW in the concordance ΛCDM universe. The discrepancy is also at the ∼2σ level. We have demonstrated that our result is robust against the varying of thresholds over a wide range.

  11. Effect of the Great Attractor on the cosmic microwave background radiation

    NASA Technical Reports Server (NTRS)

    Bertschinger, Edmund; Gorski, Krzysztof M.; Dekel, Avishai

    1990-01-01

    A map is presented of the anisotropy Delta T/T in cosmic microwave background (CMB) temperature of our region of the universe as viewed by a distant observer, predicted on the basis of the gravitational potential field. This field is calculated in the vicinity of the Local Group of galaxies from the observed peculiar velocities of galaxies under the assumption that the peculiar motions are induced by gravity. If the cosmological density parameter Omega is one, the gravitational potential field of the Great Attractor and surrounding regions produces a maximum Sachs-Wolfe anisotropy of Delta T/T = (1.7 + or - 0.3) x 10 to the -5th on an angular scale of 1 deg. Doppler and adiabatic contributions to this anisotropy are expected to be somewhat larger. If similar fluctuations in the gravitational potential are present elsewhere in the universe, the anisotropy present when the CMB was last scattered should be visible from the earth and should be detectable in current experiments.

  12. Contamination cannot explain the lack of large-scale power in the cosmic microwave background radiation

    SciTech Connect

    Bunn, Emory F.; Bourdon, Austin

    2008-12-15

    Several anomalies appear to be present in the large-angle cosmic microwave background (CMB) anisotropy maps of the Wilkinson Microwave Anisotropy Probe. One of these is a lack of large-scale power. Because the data otherwise match standard models extremely well, it is natural to consider perturbations of the standard model as possible explanations. We show that, as long as the source of the perturbation is statistically independent of the source of the primary CMB anisotropy, no such model can explain this large-scale power deficit. On the contrary, any such perturbation always reduces the probability of obtaining any given low value of large-scale power. We rigorously prove this result when the lack of large-scale power is quantified with a quadratic statistic, such as the quadrupole moment. When a statistic based on the integrated square of the correlation function is used instead, we present strong numerical evidence in support of the result. The result applies to models in which the geometry of spacetime is perturbed (e.g., an ellipsoidal universe) as well as explanations involving local contaminants, undiagnosed foregrounds, or systematic errors. Because the large-scale power deficit is arguably the most significant of the observed anomalies, explanations that worsen this discrepancy should be regarded with great skepticism, even if they help in explaining other anomalies such as multipole alignments.

  13. Compton scattering of microwave background radiation by gas in galaxy clusters

    NASA Technical Reports Server (NTRS)

    Gould, R. J.; Rephaeli, Y.

    1978-01-01

    Based on data on the X-ray spectrum of the Coma cluster, interpreted as thermal bremsstrahlung, the expected brightness depletion from Compton scattering of the microwave background in the direction of the cluster is computed. The calculated depletion is about one-third that recently observed by Gull and Northover, and the discrepancy is discussed. In comparing the observed microwave depletion in the direction of other clusters which are X-ray sources it is found that there is no correlation with the cluster X-ray luminosity. Consequently, the microwave depletion observations cannot yet be taken as good evidence for a thermal bremsstrahlung origin for the X-ray emission. The perturbation from Compton scattering of photons on the high-frequency (Wien) tail of the blackbody distribution is computed and found to be much larger than predicted in previous calculations. In the Wien tail the effect is a relative increase in the blackbody intensity that is appreciably greater in magnitude than the depletion in the Rayleigh-Jeans domain.

  14. Serum microRNAs are early indicators of survival after radiation-induced hematopoietic injury

    PubMed Central

    Acharya, Sanket S.; Fendler, Wojciech; Watson, Jacqueline; Hamilton, Abigail; Pan, Yunfeng; Gaudiano, Emily; Moskwa, Patryk; Bhanja, Payel; Saha, Subhrajit; Guha, Chandan; Parmar, Kalindi; Chowdhury, Dipanjan

    2015-01-01

    Accidental radiation exposure is a threat to human health that necessitates effective clinical planning and diagnosis. Minimally invasive biomarkers that can predict long-term radiation injury are urgently needed for optimal management after a radiation accident. We have identified serum microRNA (miRNA) signatures that indicate long-term impact of total body irradiation (TBI) in mice when measured within 24 hours of exposure. Impact of TBI on the hematopoietic system was systematically assessed to determine a correlation of residual hematopoietic stem cells (HSCs) with increasing doses of radiation. Serum miRNA signatures distinguished untreated mice from animals exposed to radiation and correlated with the impact of radiation on HSCs. Mice exposed to sublethal (6.5 Gy) and lethal (8 Gy) doses of radiation were indistinguishable for 3 to 4 weeks after exposure. A serum miRNA signature detectable 24 hours after radiation exposure consistently segregated these two cohorts. Furthermore, using either a radioprotective agent before, or radiation mitigation after, lethal radiation, we determined that the serum miRNA signature correlated with the impact of radiation on animal health rather than the radiation dose. Last, using humanized mice that had been engrafted with human CD34+ HSCs, we determined that the serum miRNA signature indicated radiation-induced injury to the human bone marrow cells. Our data suggest that serum miRNAs can serve as functional dosimeters of radiation, representing a potential breakthrough in early assessment of radiation-induced hematopoietic damage and timely use of medical countermeasures to mitigate the long-term impact of radiation. PMID:25972001

  15. Intraoperative radiation therapy in malignant glioma: early clinical results.

    PubMed

    Ortiz de Urbina, D; Santos, M; Garcia-Berrocal, I; Bustos, J C; Samblas, J; Gutierrez-Diaz, J A; Delgado, J M; Donckaster, G; Calvo, F A

    1995-08-01

    Intraoperative radiation therapy (IORT) with high energy electron beams is a treatment modality that has been included in multimodal programs in oncology to improve local tumor control. From August 1991 to December 1993, 17 patients with primary (8) or recurrent (9) high grade malignant gliomas, anaplastic astrocytoma (4), anaplastic oligodendroglioma (6) and glioblastoma multiforme (7), underwent surgical resection and a single dose of 10-20 Gy intraoperative radiation therapy was delivered in tumor bed. Fourteen patients received either pre-operative (8) or post-operative (6) external beam radiation therapy. Primary gliomas: 18-months actuarial survival rate has been 56% (range: 1-21+ months) and the median survival time has not yet been achieved. Four patients developed tumor progression (median time to tumor progression: 9 months). Recurrent gliomas: 18-months actuarial survival rate and median survival time has been 47% and 13 months (range: 6-32+ months) respectively. The median time to tumor progression was 11 months. No IORT related mortality has been observed. IORT is an attractive, tolerable and feasible treatment modality as antitumoral intensification procedure in high grade malignant gliomas.

  16. The Pliocene-Pleistocene succession of Kvabebi (Georgia) and the background to the early human occupation of Southern Caucasus

    NASA Astrophysics Data System (ADS)

    Agustí, J.; Vekua, A.; Oms, O.; Lordkipanidze, D.; Bukhsianidze, M.; Kiladze, G.; Rook, L.

    2009-12-01

    This article analyzes and discusses the chronological and zoogeographic context of the Pliocene site of Kvabebi in order to shed light into the background of the early human occupation of Eurasia, as evidenced by the early Pleistocene site of Dmanisi. New paleontological and paleomagnetic research has allowed this site to be placed in a reverse interval which can be identified as chron 2An.1r. The age of this site is therefore close to 3.07 Ma, coeval to the Hadar beds of the Afar Depression and slightly older than the last hipparionine faunas in Europe, such as Villarroya in Spain. The fauna of Kvabebi is composed of a number of species common to Europe and Asia, but also includes others with African affinities, such as Kvabebihyrax kachethicus, Protoryx heinrichi, Parastrepsiceros sokolovi and Gazella postmitilinii. However, the presence these species cannot be explained as the result of a Pliocene dispersal from Africa, but rather as the last remnants of the so-called Greek-Iranian province.

  17. The impact of background radiation, illumination and temperature on EMF-induced changes of aqua medium properties.

    PubMed

    Naira, Baghdasaryan; Yerazik, Mikayelyan; Anna, Nikoghosyan; Sinerik, Ayrapetyan

    2013-09-01

    The effects of extremely low frequency electromagnetic field (ELF EMF) on physicochemical properties of physiological solution at different environmental media were studied. The existence of frequency "windows" at 4 and 8 Hz frequencies of ELF EMF having effects on heat fusion period, hydrogen peroxide (H2O2) formation and oxygen (O2) content of water solution and different dependency on temperature, background radiation and illumination was shown. Obtained data allow us to suggest that EMF-induced effect on water physicochemical properties depends on abovementioned environmental factors. As cell bathing medium is a target for biological effects of ELF EMF, the variability of experimental data on biological effects of EMF, obtained in different laboratories, can be explained by different environmental conditions of experiments, which very often are not considered adequately.

  18. Early Test Facilities and Analytic Methods for Radiation Shielding

    SciTech Connect

    Ingersoll, D.T.

    1992-01-01

    This report represents a compilation of eight papers presented at the 1992 American Nuclear Society/European Nuclear Society International Meeting held in Chicago, Illinois on November 15 20,1992. The meeting is of special significance since it commemorates the 50th anniversary of the first controlled nuclear chain reaction, which occurred, not coincidentally, in Chicago. The papers contained in this report were presented in a special session organized by the Radiation Protection and Shielding Division in keeping with the historical theme of the meeting.

  19. Differential proteome analysis of a selected bacterial strain isolated from a high background radiation area in response to radium stress.

    PubMed

    Zakeri, Farideh; Sadeghizadeh, Majid; Kardan, Mohammad Reza; Shahbani Zahiri, Hossein; Ahmadian, Gholamreza; Masoumi, Fatemeh; Sharafi, Hakimeh; Rigi, Garshasb; Vali, Hojatollah; Akbari Noghabi, Kambiz

    2012-08-01

    The present study describes the response of a bacterial strain, isolated from a hot spring in an area with the highest levels of natural radiation, under radium ((226)Ra) stress. The bacterium has been characterized as a novel and efficient radium biosorbent and identified as a variant of Serratia marcescens by biochemical tests and molecular recognition. In order to gain insights into key cellular events that allow this strain to survive and undergo (226)Ra adaptation and biosorption, the strain was tested under two experimental conditions of 1000 and 6000 Bq (226)Ra stress. A proteomic approach involving two-dimensional polyacrylamide gel electrophoresis and mass spectrometry was used to identify the differentially expressed proteins under (226)Ra stress. Functional assessment of identified proteins with significantly altered expression levels revealed several mechanisms thought to be involved in (226)Ra adaptation and conferring resistant phenotype to the isolate, including general stress adaptation, anti-oxidative stress, protein and nucleic acid synthesis, energy metabolism, efflux and transport proteins. It suggests that this strain through evolution is particularly well adapted to the high background radiation environment and could represent an alternative source to remove (226)Ra from such areas as well as industrial radionuclide polluted wastewaters.

  20. Natural radionuclides in soil near a coal-fired power plant in the high background radiation area, South China.

    PubMed

    Liu, Guoqing; Luo, Qi; Ding, Mingxia; Feng, Jiangping

    2015-06-01

    In this study, soil samples around Mawan coal-fired power plant (CFPP) in Shenzhen, a high background radiation area in South China, were analyzed for natural radionuclides. The activity concentration of (226)Ra, (232)Th, and (40)K in soils around Mawan CFPP ranged from approximately 72 to 358 Bq kg(-1) (averaged 204 Bq kg(-1)), 118 to 432 Bq kg(-1) (averaged 265 Bq kg(-1)), and 101 to 2168 Bq kg(-1) (averaged 1269 Bq kg(-1)), respectively, being found to be significantly higher than the world range values. The levels of these radionuclides in soil largely decreased with increasing distance from the CFPP, indicating a technologically enhanced natural radiation near the CFPP. The Raeq values for the soil samples around Mawan CFPP ranged from 346 to 878 Bq kg(-1), most of which exceeded the allowed maximum Raeq value of 370 Bq kg(-1). The operating of CFPP has increased the total radioactive dose received for the nearby population. PMID:25975236

  1. The Earth Radiation Budget Experiment - Early validation results

    NASA Technical Reports Server (NTRS)

    Smith, G. L.; Barkstrom, B. R.; Harrison, E. F.; Huck, F. O.; Cess, R.; Coakley, J.; Duncan, C.; King, M.; Mecherikunnel, A.; Gruber, A.

    1986-01-01

    The primary techniques used to obtain and validate the data of the Earth Radiation Budget Experiment (ERBE) are described, together with preliminary results of the validation. The ERBE consists of radiometers aboard the ERB Satellite, dedicated to a 57-deg orbit, and each of the two NOAA meteorological spacecraft (NOAA 9 and NOAA G) in near polar orbits. The radiometers include scanning narrow field-of-view (FOV) and nadir-looking wide and medium FOV radiometers, and a solar monitoring channel. Measurements of the solar constant by the solar monitors, and the wide and medium FOV radiometers of the ERB and the NOAA 9 spacecraft agree within a fraction of a percent. Comparison of the wide and medium FOV radiometers with the scanning radiometers showed an agreement of 1 to 4 percent. The multiple ERBE satellites are acquiring the first global measurements of regional scale-diurnal variations in the earth's radiation budget. These were verified by comparison with the high-temporal-resolution geostationary satellite data.

  2. The cosmic microwave background radiation as a probe of the large-scale structure of the universe

    NASA Technical Reports Server (NTRS)

    Silk, J.

    1982-01-01

    Cosmological and astrophysical implications of large scale fluctuations in the cosmic microwave background are discussed, with attention given to galaxy formation. Angular anisotropies are mentioned as yielding information on the matter distribution during early epochs, characterized by inhomogeneities which persist on large scales. Factors such as the curvature of the universe and the hypothesis of massive neutrinos with m more than 30 eV affect the observed anomalies, which can be traced backwards to determine the source of nonlinear structures. Neutrino rest masses of less than a few eV imply isothermal fluctuations in the initial conditions, while gaseous fragmentation of adiabatic pancakes does provide a basis for an acceptable galaxy formation and clustering scenario. However, the primordial isothermal fluctuations fit well with observational constraints imposed by a neutrino-dominated universe.

  3. Regulation of early and delayed radiation responses in rat small intestine by capsaicin-sensitive nerves

    SciTech Connect

    Wang Junru; Zheng Huaien; Kulkarni, Ashwini; Ou Xuemei; Hauer-Jensen, Martin . E-mail: mhjensen@life.uams.edu

    2006-04-01

    Purpose: Mast cells protect against the early manifestations of intestinal radiation toxicity, but promote chronic intestinal wall fibrosis. Intestinal sensory nerves are closely associated with mast cells, both anatomically and functionally, and serve an important role in the regulation of mucosal homeostasis. This study examined the effect of sensory nerve ablation on the intestinal radiation response in an established rat model. Methods and Materials: Rats underwent sensory nerve ablation with capsaicin or sham ablation. Two weeks later, a localized segment of ileum was X-irradiated or sham irradiated. Structural, cellular, and molecular changes were examined 2 weeks (early injury) and 26 weeks (chronic injury) after irradiation. The mast cell dependence of the effect of sensory nerve ablation on intestinal radiation injury was assessed using c-kit mutant (Ws/Ws) mast cell-deficient rats. Results: Capsaicin treatment caused a baseline reduction in mucosal mast cell density, crypt cell proliferation, and expression of substance P and calcitonin gene-related peptide, two neuropeptides released by sensory neurons. Sensory nerve ablation strikingly exacerbated early intestinal radiation toxicity (loss of mucosal surface area, inflammation, intestinal wall thickening), but attenuated the development of chronic intestinal radiation fibrosis (collagen I accumulation and transforming growth factor {beta} immunoreactivity). In mast cell-deficient rats, capsaicin treatment exacerbated postradiation epithelial injury (loss of mucosal surface area), but none of the other aspects of radiation injury were affected by capsaicin treatment. Conclusions: Ablation of capsaicin-sensitive enteric neurons exacerbates early intestinal radiation toxicity, but attenuates development of chronic fibroproliferative changes. The effect of capsaicin treatment on the intestinal radiation response is partly mast cell dependent.

  4. Early events in radiation chemistry and in photoionization

    SciTech Connect

    Trifunac, A.D.; Loffredo, D.M.; Liu, A.-D.

    1992-01-01

    Real-time studies of aliphatic and aromatic hydrocarbons by pulse radiolysis and laser photoionization reveal the chemistry of the ionic species in the condensed phase. The occurrence of radical cation reactions with solvent molecules provides the core mechanism capable of explaining a wide range of observations in photoionization and radiation chemistry. The study of products and transients in photoionization of aromatic solutes in hydrocarbon and alcohol solvent illustrates several details of this high-energy'' chemistry. A reaction pathway involving ion-molecule reaction of excited ions is indicated for a series of polycyclic aromatic hydrocarbons photoionized using intense excimer laser (248 and 308 nm) pulses in hydrocarbon and alcohol solutions. We have found that condensed-phase ion-molecule reactions in radiolysis are ubiquitous and we speculate on their overall role in hydrocarbon radiolysis.

  5. Early events in radiation chemistry and in photoionization

    SciTech Connect

    Trifunac, A.D.; Loffredo, D.M.; Liu, A.-D.

    1992-12-31

    Real-time studies of aliphatic and aromatic hydrocarbons by pulse radiolysis and laser photoionization reveal the chemistry of the ionic species in the condensed phase. The occurrence of radical cation reactions with solvent molecules provides the core mechanism capable of explaining a wide range of observations in photoionization and radiation chemistry. The study of products and transients in photoionization of aromatic solutes in hydrocarbon and alcohol solvent illustrates several details of this ``high-energy`` chemistry. A reaction pathway involving ion-molecule reaction of excited ions is indicated for a series of polycyclic aromatic hydrocarbons photoionized using intense excimer laser (248 and 308 nm) pulses in hydrocarbon and alcohol solutions. We have found that condensed-phase ion-molecule reactions in radiolysis are ubiquitous and we speculate on their overall role in hydrocarbon radiolysis.

  6. The earth radiation budget experiment: Early validation results

    NASA Astrophysics Data System (ADS)

    Smith, G. Louis; Barkstrom, Bruce R.; Harrison, Edwin F.

    The Earth Radiation Budget Experiment (ERBE) consists of radiometers on a dedicated spacecraft in a 57° inclination orbit, which has a precessional period of 2 months, and on two NOAA operational meteorological spacecraft in near polar orbits. The radiometers include scanning narrow field-of-view (FOV) and nadir-looking wide and medium FOV radiometers covering the ranges 0.2 to 5 μm and 5 to 50 μm and a solar monitoring channel. This paper describes the validation procedures and preliminary results. Each of the radiometer channels underwent extensive ground calibration, and the instrument packages include in-flight calibration facilities which, to date, show negligible changes of the instruments in orbit, except for gradual degradation of the suprasil dome of the shortwave wide FOV (about 4% per year). Measurements of the solar constant by the solar monitors, wide FOV, and medium FOV radiometers of two spacecraft agree to a fraction of a percent. Intercomparisons of the wide and medium FOV radiometers with the scanning radiometers show agreement of 1 to 4%. The multiple ERBE satellites are acquiring the first global measurements of regional scale diurnal variations in the Earth's radiation budget. These diurnal variations are verified by comparison with high temporal resolution geostationary satellite data. Other principal investigators of the ERBE Science Team are: R. Cess, SUNY, Stoneybrook; J. Coakley, NCAR; C. Duncan, M. King and A Mecherikunnel, Goddard Space Flight Center, NASA; A. Gruber and A.J. Miller, NOAA; D. Hartmann, U. Washington; F.B. House, Drexel U.; F.O. Huck, Langley Research Center, NASA; G. Hunt, Imperial College, London U.; R. Kandel and A. Berroir, Laboratory of Dynamic Meteorology, Ecole Polytechique; V. Ramanathan, U. Chicago; E. Raschke, U. of Cologne; W.L. Smith, U. of Wisconsin and T.H. Vonder Haar, Colorado State U.

  7. Radiative transfer in CO2-rich atmospheres: 1. Collisional line mixing implies a colder early Mars

    NASA Astrophysics Data System (ADS)

    Ozak, N.; Aharonson, O.; Halevy, I.

    2016-06-01

    Fast and accurate radiative transfer methods are essential for modeling CO2-rich atmospheres, relevant to the climate of early Earth and Mars, present-day Venus, and some exoplanets. Although such models already exist, their accuracy may be improved as better theoretical and experimental constraints become available. Here we develop a unidimensional radiative transfer code for CO2-rich atmospheres, using the correlated k approach and with a focus on modeling early Mars. Our model differs from existing models in that it includes the effects of CO2 collisional line mixing in the calculation of the line-by-line absorption coefficients. Inclusion of these effects results in model atmospheres that are more transparent to infrared radiation and, therefore, in colder surface temperatures at radiative-convective equilibrium, compared with results of previous studies. Inclusion of water vapor in the model atmosphere results in negligible warming due to the low atmospheric temperatures under a weaker early Sun, which translate into climatically unimportant concentrations of water vapor. Overall, the results imply that sustained warmth on early Mars would not have been possible with an atmosphere containing only CO2 and water vapor, suggesting that other components of the early Martian climate system are missing from current models or that warm conditions were not long lived.

  8. Sulfur, ultraviolet radiation, and the early evolution of life

    NASA Technical Reports Server (NTRS)

    Kasting, J. F.; Zahnle, K. J.; Pinto, J. P.; Young, A. T.

    1989-01-01

    The present biosphere is shielded from harmful solar near ultraviolet (UV) radiation by atmospheric ozone. It is suggested that elemental sulfur vapor could have played a similar role in an anoxic, ozone-free, primitive atmosphere. Sulfur vapor would have been produced photochemically from volcanogenic SO2 and H2S. It is composed of ring molecules, primarily S8, that absorb strongly throughout the near UV, yet are expected to be relatively stable against photolysis and chemical attack. It is also insoluble in water and would thus have been immune to rainout or surface deposition over the oceans. Since the concentration of S8 in the primitive atmosphere would have been limited by its saturation vapor pressure, surface temperatures of 45 C or higher, corresponding to carbon dioxide partial pressures exceeding 2 bars, are required to sustain an effective UV screen. A warm, sulfur-rich, primitive atmosphere is consistent with inferences drawn from molecular phylogeny, which suggest that some of the earliest organisms were thermophilic bacteria that metabolized elemental sulfur.

  9. Reducing the uncertainty in background marine aerosol radiative properties using CAM5 model results and CALIPSO-retrievals

    NASA Astrophysics Data System (ADS)

    Meskhidze, N.; Gantt, B.; Dawson, K.; Johnson, M. S.; Gasso, S.

    2012-12-01

    Abundance of natural aerosols in the atmosphere strongly affects global aerosol optical depth (AOD) and influences clouds and the hydrological cycle through its ability to act as cloud condensation nuclei (CCN). Because the anthropogenic contribution to climate forcing represents the difference between the total forcing and that from natural aerosols, understanding background aerosols is necessary to evaluate the influences of anthropogenic aerosols on cloud reflectivity and persistence (so-called indirect radiative forcing). The effects of marine aerosols are explored using remotely sensed data obtained by Cloud-aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) and the NCAR Community Atmosphere Model (CAM5.0), coupled with the PNNL Modal Aerosol Model. CALIPSO-provided high resolution vertical profile information about different aerosol subtypes (defined as clean continental, marine, desert dust, polluted continental, polluted dust, and biomass burning), particulate depolarization ratio (or particle non-sphericity), reported aerosol color ratio (the ratio of aerosol backscatter at the two wavelengths) and lidar ratios over different parts of the oceans are compared to model-simulations to help evaluate the contribution of biogenic aerosol to CCN budget in the marine boundary layer. Model-simulations show that over biologically productive ocean waters primary organic aerosols of marine origin can contribute up to a 20% increase in CCN (at a supersaturation of 0.2%) number concentrations. Corresponding changes associated with cloud properties (liquid water path and droplet number) can decrease global annual mean indirect radiative forcing of anthropogenic aerosol (less cooling) by ~0.1 Wm-2 (7%). This study suggests ignoring the complex chemical composition and size distribution of sea spray particles could result in considerable uncertainties in predicted anthropogenic aerosol indirect effect.

  10. A mentor training program improves mentoring competency for researchers working with early-career investigators from underrepresented backgrounds.

    PubMed

    Johnson, Mallory O; Gandhi, Monica

    2015-08-01

    Mentoring is increasingly recognized as a critical element in supporting successful careers in academic research in medicine and related disciplines, particularly for trainees and early career investigators from underrepresented backgrounds. Mentoring is often executed ad hoc; there are limited programs to train faculty to become more effective mentors, and the few that exist have a dearth of empirical support of their impact. In 2013, we recruited 34 faculty from across the US engaged in HIV-related clinical research to participate in a 2-day Mentoring the Mentors workshop. The workshop included didactic and interactive content focused on a range of topics, such as mentor-mentee communication, leadership styles, emotional intelligence, understanding the impact of diversity (unconscious bias, microaggressions, discrimination, tokenism) for mentees, and specific tools and techniques for effective mentoring. Pre- and post-workshop online evaluations documented high rates of satisfaction with the program and statistically significant improvements in self-appraised mentoring skills (e.g. addressing diversity in mentoring, communication with mentees, aligning mentor-mentee expectations), as assessed via a validated mentoring competency tool. This is the first mentoring training program focused on enhancing mentors' abilities to nurture investigators of diversity, filling an important gap, and evaluation results offer support for its effectiveness. Results suggest a need for refinement and expansion of the program and for more comprehensive, long-term evaluation of distal mentoring outcomes for those who participate in the program. PMID:25274417

  11. A mentor training program improves mentoring competency for researchers working with early-career investigators from underrepresented backgrounds.

    PubMed

    Johnson, Mallory O; Gandhi, Monica

    2015-08-01

    Mentoring is increasingly recognized as a critical element in supporting successful careers in academic research in medicine and related disciplines, particularly for trainees and early career investigators from underrepresented backgrounds. Mentoring is often executed ad hoc; there are limited programs to train faculty to become more effective mentors, and the few that exist have a dearth of empirical support of their impact. In 2013, we recruited 34 faculty from across the US engaged in HIV-related clinical research to participate in a 2-day Mentoring the Mentors workshop. The workshop included didactic and interactive content focused on a range of topics, such as mentor-mentee communication, leadership styles, emotional intelligence, understanding the impact of diversity (unconscious bias, microaggressions, discrimination, tokenism) for mentees, and specific tools and techniques for effective mentoring. Pre- and post-workshop online evaluations documented high rates of satisfaction with the program and statistically significant improvements in self-appraised mentoring skills (e.g. addressing diversity in mentoring, communication with mentees, aligning mentor-mentee expectations), as assessed via a validated mentoring competency tool. This is the first mentoring training program focused on enhancing mentors' abilities to nurture investigators of diversity, filling an important gap, and evaluation results offer support for its effectiveness. Results suggest a need for refinement and expansion of the program and for more comprehensive, long-term evaluation of distal mentoring outcomes for those who participate in the program.

  12. Modeling the Early Annihilation Radiation Spectrum from INTEGRAL/SPI

    NASA Astrophysics Data System (ADS)

    Guessoum, N.; Jean, P.; Knödlseder, J.; Lonjou, V.; von Ballmoos, P.; Weidenspointer, G.

    2004-10-01

    We undertake to model the spectrum of the galactic annihilation radiation, using the preliminary data obtained by INTEGRAL/SPI (Jean et al. 2003; Jean et al. 2004; Lonjou et al. 2004). We use the general line spectroscopy approach developed by Guessoum et al. (1991), where the interstellar medium (ISM) is divided into 5 phases: cold, warm neutral, warm ionized, and hot, in addition to a dust grain fraction, each characterized by proper physical parameters. Each phase presents us with particular positron annihilation processes, rates, and line widths. Best- fitting the model spectrum to the SPI data (through a chi-square minimization approach) then allows us to obtain "best values" for the ISM phase fractions (density times filling factor) along with uncertainties. Noting that the (astrophysical) line width determined by SPI (3.0 ± 0.5 keV in the first set of data and 2.7 ± 0.3 keV in the most recent analysis; Lonjou et al. 2004) is rather significantly larger than the value derived by the TGRS measurements (Harris et al. 1998), i.e. 1.8 ± 0.5 keV, we submitted the TGRS data to the same analysis. We should also note, however, that the width of the line obtained from the previous Germanium-detector observation missions, namely GRIS and HEXAGONE, were 2.5±0.4 keV ("weighted mean" from 3 observation campaigns; (Leventhal et al. 1993) and 2.66±0.6 keV (Durouchoux et al. 1993), respectively. The results suggest annihilation in a medium that is warmer or hotter (more fully ionized) and quite devoid of grains, compared to the dustier and hotter (overall) medium suggested by the SPI data. We briefly discuss these results and possible interpretations as well as follow-up analyses and proposed observations.

  13. Potentially Missing Physics of the Early Universe: Nonlinear Vacuum Polarization in Intense Blackbody Radiation

    SciTech Connect

    Wu, S Q; Hartemann, F V

    2010-04-13

    The standard Big Bang universe model is mainly based on linear interactions, except during exotic periods such as inflation. The purpose of the present proposal is to explore the effects, if any, of vacuum polarization in the very high energy density environment of the early universe. These conditions can be found today in astrophysical settings and may also be emulated in the laboratory using high intensity advanced lasers. Shortly after the Big Bang, there once existed a time when the energy density of the universe corresponded to a temperature in the range 10{sup 8} - 10{sup 9} K, sufficient to cause vacuum polarization effects. During this period, the nonlinear vacuum polarization may have had significant modifications on the propagation of radiation. Thus the thermal spectrum of the early universe may have been starkly non-Planckian. Measurements of the cosmic microwave background today show a spectrum relatively close to an ideal blackbody. Could the early universe have shown spectral deviations due to nonlinear vacuum effects? If so, is it possible to detect traces of those relic photons in the universe today? Found in galactic environments, compact objects such as blazars and magnetars can possess astronomically large energy densities that far exceed anything that can be created in the laboratory. Their field strengths are known to reach energy levels comparable to or surpassing the energy corresponding to the Schwinger critical field E {approx} 10{sup 18} V/m. Nonlinear vacuum effects become prominent under these conditions and have garnered much interest from the astronomical and theoretical physics communities. The effects of a nonlinear vacuum may be of crucial importance for our understanding of these objects. At energies of the order of the electron rest mass, the most important interactions are described by quantum electrodynamics (QED). It is predicted that nonlinear photon-photon interactions will occur at energies approaching the Schwinger

  14. Recombinant Thrombomodulin (Solulin) Ameliorates Early Intestinal Radiation Toxicity in a Preclinical Rat Model.

    PubMed

    Pathak, Rupak; Wang, Junru; Garg, Sarita; Aykin-Burns, Nukhet; Petersen, Karl-Uwe; Hauer-Jensen, Martin

    2016-08-01

    Intestinal radiation toxicity occurs during and after abdominopelvic radiotherapy. Endothelial cells play a significant role in modulating radiation-induced intestinal damage. We demonstrated that the endothelial cell surface receptor thrombomodulin (TM), a protein with anticoagulant, anti-inflammatory and antioxidant properties, mitigates radiation-induced lethality in mice. The goal of this study was to determine whether recombinant TM (Solulin) can protect the intestine from toxicity in a clinically relevant rat model. A 4 cm loop of rat small bowel was exposed to fractionated 5 Gy X radiation for 9 consecutive days. The animals were randomly assigned to receive daily subcutaneous injections of vehicle or Solulin (3 mg/kg/day or 10 mg/kg/day) for 27 days starting 4 days before irradiation. Early intestinal injury was assessed two weeks after irradiation by quantitative histology, morphometry, immunohistochemistry and luminol bioluminescence imaging. Solulin treatment significantly ameliorated intestinal radiation injury, made evident by a decrease in myeloperoxidase (MPO) activity, transforming growth factor beta (TGF-β) immunoreactivity, collagen-I deposition, radiation injury score (RIS) and intestinal serosal thickening. These findings indicate the need for further development of Solulin as a prophylactic and/or therapeutic agent to mitigate radiation-induced intestinal damage. PMID:27459702

  15. Recombinant Thrombomodulin (Solulin) Ameliorates Early Intestinal Radiation Toxicity in a Preclinical Rat Model

    PubMed Central

    Pathak, Rupak; Wang, Junru; Garg, Sarita; Aykin-Burns, Nukhet; Petersen, Karl-Uwe; Hauer-Jensen, Martin

    2016-01-01

    Intestinal radiation toxicity occurs during and after abdominopelvic radiotherapy. Endothelial cells play a significant role in modulating radiation-induced intestinal damage. We demonstrated that the endothelial cell surface receptor thrombomodulin (TM), a protein with anticoagulant, antiinflammatory and antioxidant properties, mitigates radiation-induced lethality in mice. The goal of this study was to determine whether recombinant TM (Solulin) can protect the intestine from toxicity in a clinically relevant rat model. A 4 cm loop of rat small bowel was exposed to fractionated 5 Gy X radiation for 9 consecutive days. The animals were randomly assigned to receive daily subcutaneous injections of vehicle or Solulin (3 mg/kg/day or 10 mg/kg/day) for 27 days starting 4 days before irradiation. Early intestinal injury was assessed two weeks after irradiation by quantitative histology, morphometry, immunohistochemistry and luminol bioluminescence imaging. Solulin treatment significantly ameliorated intestinal radiation injury, made evident by a decrease in myeloperoxidase (MPO) activity, transforming growth factor beta (TGF-β) immunoreactivity, collagen-I deposition, radiation injury score (RIS) and intestinal serosal thickening. These findings indicate the need for further development of Solulin as a prophylactic and/or therapeutic agent to mitigate radiation-induced intestinal damage. PMID:27459702

  16. Early and Late Damages in Chromosome 3 of Human Lymphocytes After Radiation Exposure

    NASA Technical Reports Server (NTRS)

    Sunagawa, Mayumi; Mangala, Lingegowda; Zhang, Ye; Kahdim, Munira; Wilson, Bobby; Cucinotta, Francis A.; Wu, Honglu

    2011-01-01

    Tumor formation in humans or animals is a multi-step process. An early stage of cancer development is believed to be genomic instability (GI) which accelerates the mutation rate in the descendants of the cells surviving radiation exposure. GI is defined as elevated or persistent genetic damages occurring many generations after the cells are exposed. While early studies have demonstrated radiation-induced GI in several cell types as detected in endpoints such as mutation, apoptosis and damages in chromosomes, the dependence of GI on the quality of radiation remains uncertain. To investigate GI in human lymphocytes induced by both low- and high-LET radiation, we initially exposed white blood cells collected from healthy subjects to gamma rays in vitro, and cultured the cells for multiple generations. Chromosome aberrations were analyzed in cells collected at first mitosis post irradiation and at several intervals during the culture period. Among a number of biological endpoints planned for the project, the multi-color banding fluorescent in situ hybridization (mBAND) allows identification of inversions that were expected to be stable. We present here early and late chromosome aberrations detected with mBAND in chromosome 3 after gamma exposure. Comparison of chromosome damages in between human lymphocytes and human epithelial cells is also discussed

  17. Sparsely ionizing diagnostic and natural background radiations are likely preventing cancer and other genomic-instability-associated diseases.

    PubMed

    Scott, Bobby R; Di Palma, Jennifer

    2007-01-01

    Routine diagnostic X-rays (e.g., chest X-rays, mammograms, computed tomography scans) and routine diagnostic nuclear medicine procedures using sparsely ionizing radiation forms (e.g., beta and gamma radiations) stimulate the removal of precancerous neo-plastically transformed and other genomically unstable cells from the body (medical radiation hormesis). The indicated radiation hormesis arises because radiation doses above an individual-specific stochastic threshold activate a system of cooperative protective processes that include high-fidelity DNA repair/apoptosis (presumed p53 related), an auxiliary apoptosis process (PAM process) that is presumed p53-independent, and stimulated immunity. These forms of induced protection are called adapted protection because they are associated with the radiation adaptive response. Diagnostic X-ray sources, other sources of sparsely ionizing radiation used in nuclear medicine diagnostic procedures, as well as radioisotope-labeled immunoglobulins could be used in conjunction with apoptosis-sensitizing agents (e.g., the natural phenolic compound resveratrol) in curing existing cancer via low-dose fractionated or low-dose, low-dose-rate therapy (therapeutic radiation hormesis). Evidence is provided to support the existence of both therapeutic (curing existing cancer) and medical (cancer prevention) radiation hormesis. Evidence is also provided demonstrating that exposure to environmental sparsely ionizing radiations, such as gamma rays, protect from cancer occurrence and the occurrence of other diseases via inducing adapted protection (environmental radiation hormesis). PMID:18648608

  18. [Modern possibilities of medicinal prophylaxis and early therapy of radiation injuries].

    PubMed

    Grebeniuk, A N; Zatsepin, V V; Nazarov, V B; Vlasenko, T N

    2011-02-01

    Medical antiradiation protection is one of the key factors determining fighting capacity of armies. The basis of medical protection in the countries of the NATO is made with the preparations used up to an irradiation (radioprotector WR-2721) and at the first time after radiating influence. The Russian system of antiradiation protection includes radioprotectors, drugs for prophylaxis and treatment of syndrome of primary reaction to an irradiation, means of early therapy of radiation injure, preparations for sorption and elimination of radionuclides, got in an organism. PMID:21770338

  19. Early Cenozoic radiations in the Antarctic marine realm and their evolutionary implications

    NASA Astrophysics Data System (ADS)

    Crame, Alistair

    2014-05-01

    The extensive and very well exposed Late Cretaceous - Early Paleogene sedimentary succession of Seymour Island, NE Antarctic Peninsula presents a unique opportunity to examine Early Cenozoic evolutionary radiations in a variety of macrofaunal taxa. Building on the extensive pioneer studies by US and Argentinian palaeontologists, recent investigations have focused on refining litho-, bio- and chronostratigraphies, and taxonomic revisions to a number of key groups. Within the numerically dominant Mollusca, the balance of faunas changes significantly across the Cretaceous/Paleogene boundary, with gastropods becoming numerically dominant for the first time in the Early Paleocene Sobral Formation (SF). At this level seven of the 31 gastropod genera present (= 23%) can be referred to modern Southern Ocean taxa and the same figure is maintained in the Early Eocene La Meseta Formation (LMF) where 21 of 63 genera are modern. A major reason for the rise of the gastropods in the earliest Cenozoic of Antarctica is a significant radiation of the Neogastropoda, which today forms one of the largest clades in the sea. 50% of the SF gastropod fauna and 53% of the LMF at the species level are neogastropods. This important burst of speciation is linked to a major pulse of global warming from ~63 - 43Ma when warm temperate conditions prevailed for long intervals of time at 65ºS. The marked Early Paleogene radiation of neogastropods in Antarctica represents a distinct pulse of southern high-latitude taxa that was coeval with similar tropical/subtropical radiations in localities such as the US Gulf Coast and NW Europe. Thus it would appear that the Early Cenozoic radiation of this major taxon was truly global in scale and not just confined to one latitudinal belt. Whereas it is possible to regard a significant proportion of the modern bivalve fauna as relicts, and thus Antarctica as an evolutionary refugium, or sink, it is much less easy to do so for the Neogastropoda. At least in the

  20. Preliminary test Results for a 25K Sorption Cryocooler Designed for the UCSB Long Duration Balloon Cosmic Microwave Background Radiation Experiment

    NASA Technical Reports Server (NTRS)

    Wade, L. A.; Levy, A. R.

    1996-01-01

    A continuous operation, vibration-free, long-life 25K sorption cryocooler has been built and is now in final integration and performance testing. This cooler wil be flown on the University of California at Santa Barbara (UCSB) Long Duration Balloon (LDB) Cosmic Microwave Background Radiation Experiment.

  1. Warming early Mars with carbon dioxide clouds that scatter infrared radiation.

    PubMed

    Forget, F; Pierrehumbert, R T

    1997-11-14

    Geomorphic evidence that Mars was warm enough to support flowing water about 3.8 billion years ago presents a continuing enigma that cannot be explained by conventional greenhouse warming mechanisms. Model calculations show that the surface of early Mars could have been warmed through a scattering variant of the greenhouse effect, resulting from the ability of the carbon dioxide ice clouds to reflect the outgoing thermal radiation back to the surface. This process could also explain how Earth avoided an early irreversible glaciation and could extend the size of the habitable zone on extrasolar planets around stars.

  2. Warming early Mars with carbon dioxide clouds that scatter infrared radiation.

    PubMed

    Forget, F; Pierrehumbert, R T

    1997-11-14

    Geomorphic evidence that Mars was warm enough to support flowing water about 3.8 billion years ago presents a continuing enigma that cannot be explained by conventional greenhouse warming mechanisms. Model calculations show that the surface of early Mars could have been warmed through a scattering variant of the greenhouse effect, resulting from the ability of the carbon dioxide ice clouds to reflect the outgoing thermal radiation back to the surface. This process could also explain how Earth avoided an early irreversible glaciation and could extend the size of the habitable zone on extrasolar planets around stars. PMID:9360920

  3. [The influence of circadian rhythms of geomagnetic field variations and the background cosmic radiation on nitric oxide production in human organism].

    PubMed

    Iamshanov, V A; Koshelevskiĭ, V K

    2012-01-01

    The circadian rhythms of background gamma-radiation and Ki-indexes of geomagnetic activity (GMF) during August-September 2008, January-February 2010 and March 2011 were studied. The authors show that in summer period the maximum of Ki-indexes and gamma-radiation were at 3 p.m. of local time. In winter these maximums were shifted at more last time. It was suggested that an organism produces the own free radicals as nitric oxide to neutralize radicals from background radiation. They are formed during decay of neutrophiles when GMF-activity falls. On the other side, the production of NO is regulated by melatonin synthesis which has a circadian rhythm.

  4. Timing and Tempo of Early and Successive Adaptive Radiations in Macaronesia

    PubMed Central

    Kim, Seung-Chul; McGowen, Michael R.; Lubinsky, Pesach; Barber, Janet C.; Mort, Mark E.; Santos-Guerra, Arnoldo

    2008-01-01

    The flora of Macaronesia, which encompasses five Atlantic archipelagos (Azores, Canaries, Madeira, Cape Verde, and Salvage), is exceptionally rich and diverse. Spectacular radiation of numerous endemic plant groups has made the Macaronesian islands an outstanding area for studies of evolution and speciation. Despite intensive investigation in the last 15 years, absolute age and rate of diversification are poorly known for the flora of Macaronesia. Here we report molecular divergence estimates and rates of diversification for five representative, putative rapid radiations of monophyletic endemic plant lineages across the core eudicot clade of flowering plants. Three discrete windows of colonization during the Miocene and early Pliocene are suggested for these lineages, all of which are inferred to have had a single colonization event followed by rapid radiation. Subsequent inter-archipelago dispersal events into Madeira and the Cape Verdes took place very recently during the late Pliocene and Pleistocene after initial diversification on the Canary Islands. The tempo of adaptive radiations differs among the groups, but is relatively rapid compared to continental and other island radiations. Our results demonstrate that opportunity for island colonization and successful radiation may have been constrained to discrete time periods of profound climatic and geological changes in northern African and the Mediterranean. PMID:18478126

  5. Radiation hazards of radio frequency waves on the early embryonic development of Zebrafish

    NASA Astrophysics Data System (ADS)

    Harkless, Ryan; Al-Quraishi, Muntather; Vagula, Mary C.

    2014-06-01

    With the growing use of wireless devices in almost all day-to-day activities, exposure to radio-frequency radiation has become an immediate health concern. It is imperative that the effects of such radiation not only on humans, but also on other organisms be well understood. In particular, it is critical to understand if RF radiation has any bearing on the gene expression during embryonic development, as this is a crucial and delicate phase for any organism. Owing to possible effects that RF radiation may have on gene expression, it is essential to explore the carcinogenic or teratogenic properties that it may show. This study observed the effects of RF radiation emitted from a cellular telephone on the embryonic development of zebra fish. The expression of the gene shha plays a key role in the early development of the fish. This gene has homologs in humans as well as in other model organisms. Additionally, several biomarkers indicative of cell stress were examined: including lactate dehydrogenase (LDH), superoxide dismutase (SOD), and lipid peroxidation (LPO). Results show a significant decrease in the expression of shha, a significant decrease in LDH activity. There was no significant increase in SOD and LPO activity. No morphological abnormalities were observed in the developing embryos. At present, these results indicate that exposure to cell phone radiation may have a suppressive effect on expression of shha in D. rerio, though such exposure does not appear to cause morphological detriments. More trials are underway to corroborate these results.

  6. Sensitivity to UV radiation in early life stages of the Mediterranean sea urchin Sphaerechinus granularis (Lamarck).

    PubMed

    Nahon, Sarah; Castro Porras, Viviana A; Pruski, Audrey M; Charles, François

    2009-03-01

    The sea urchin Sphaerechinus granularis was used to investigate the impact of relevant levels of UV-B radiation on the early life stages of a common Mediterranean free spawning benthic species. Sperm, eggs and embryos were exposed to a range of UV radiation doses. The resulting endpoints were evaluated in terms of fertilisation success, development and survival rates. Above a weighted UV radiation dose of 0.0029 kJ m(-2), fertilisation capability of irradiated sperm decreased rapidly. The exposure of the eggs to 0.0175 kJ m(-2) and more led to delayed and inhibited development with ensuing embryonic morphological abnormalities. One-day old larvae remained strongly sensitive to UV radiation as shown by the 50% decrease of the larval survival rate for a dose of 0.025 kJ m(-2) UVR. The elevated sensitivity of embryos to experimental UVR went along with a lack of significant amount of sunscreen compounds (e.g., mycosporine-like amino acids) in the eggs. The present results demonstrated that gamete viability and embryonic development may be significantly impaired by solar UV radiation in S. granularis, compromising in this way the reproduction of the species. Unless adaptive behavioural reproductive strategies exist, the influence of ambient UV radiation appears as a selective force for population dynamics of broadcast spawners in the shallow benthic Mediterranean environment. PMID:19157510

  7. Biological effects of high ultraviolet radiation on early earth--a theoretical evaluation.

    PubMed

    Cockell, C S

    1998-08-21

    The surface of early Earth was exposed to both UVC radiation (< 280 nm) and higher doses of UVB (280-315 nm) compared with the surface of present day Earth. The degree to which this radiation environment acted as a selection pressure on organisms and biological systems has rarely been theoretically examined with respect to the biologically effective irradiances that ancient organisms would receive. Here action spectra for DNA inactivation and isolated chloroplast inhibition are used to estimate biologically effective irradiances on archean Earth. Comparisons are made with present day Earth. The theoretical estimations on the UV radiation screening required to protect DNA on archean Earth compare well with field and laboratory observations on protection strategies found in present day microbial communities. They suggest that many physical and biological methods may have been effective and would have allowed for the radiation of life even under the high UV radiation regimes of archean Earth. Such strategies would also have provided effective reduction of photoinhibition by UV radiation. The data also suggest that the UV regime on the surface of Mars is not a life limiting factor per se, although other environmental factors such as desiccation and low temperatures may contribute towards the apparent lack of a surface biota.

  8. Prospective Study of Local Control and Late Radiation Toxicity After Intraoperative Radiation Therapy Boost for Early Breast Cancer

    SciTech Connect

    Chang, David W.; Marvelde, Luc te; Chua, Boon H.

    2014-01-01

    Purpose: To report the local recurrence rate and late toxicity of intraoperative radiation therapy (IORT) boost to the tumor bed using the Intrabeam System followed by external-beam whole-breast irradiation (WBI) in women with early-stage breast cancer in a prospective single-institution study. Methods and Materials: Women with breast cancer ≤3 cm were recruited between February 2003 and May 2005. After breast-conserving surgery, a single dose of 5 Gy IORT boost was delivered using 50-kV x-rays to a depth of 10 mm from the applicator surface. This was followed by WBI to a total dose of 50 Gy in 25 fractions. Patients were reviewed at regular, predefined intervals. Late toxicities were recorded using the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer Late Radiation Morbidity Scoring systems. Results: Fifty-five patients completed both IORT boost and external-beam WBI. Median follow-up was 3.3 years (range, 1.4-4.1 years). There was no reported locoregional recurrence or death. One patient developed distant metastases. Grade 2 and 3 subcutaneous fibrosis was detected in 29 (53%) and 8 patients (15%), respectively. Conclusions: The use of IORT as a tumor bed boost using kV x-rays in breast-conserving therapy was associated with good local control but a clinically significant rate of grade 2 and 3 subcutaneous fibrosis.

  9. Cell phone radiations affect early growth of Vigna radiata (mung bean) through biochemical alterations.

    PubMed

    Sharma, Ved Parkash; Singh, Harminder Pal; Batish, Daizy Rani; Kohli, Ravinder Kumar

    2010-01-01

    The indiscriminate use of wireless technologies, particularly of cell phones, has increased the health risks among living organisms including plants. We investigated the impact of cell phone electromagentic field (EMF) radiations (power density, 8.55 microW cm(-2)) on germination, early growth, proteins and carbohydrate contents, and activities of some enzymes in Vigna radiata. Cell phone EMF radiations significantly reduced the seedling length and dry weight of V radiata after exposure for 0.5, 1, 2, and 4 h. Furthermore, the contents of proteins and carbohydrates were reduced in EMF-exposed plants. However, the activities of proteases, alpha-amylases, beta-amylases, polyphenol oxidases, and peroxidases were enhanced in EMF-exposed radicles indicating their role in providing protection against EMF-induced stress. The study concludes that cell phone EMFs impair early growth of V radiata seedlings by inducing biochemical changes.

  10. [Radiation studies in the detection of early signs of lung tissue lesion in sarcoidosis].

    PubMed

    Stashuk, G A; Dubrova, S E

    2007-01-01

    The capacities of various radiation techniques in the study of patients with pulmonary sarcoidosis are analyzed. The sequence of their use, which ensures a high informative value, is proposed. By analyzing the X-ray semiotics in 45 patients with pulmonary sarcoidosis, the authors give the diagnostic signs of early lung parenchymal damage in this disease. Particular emphasis is placed on the procedure of lung X-ray computed tomography.

  11. An analysis of partial 28S ribosomal RNA sequences suggests early radiations of sponges.

    PubMed

    Lafay, B; Boury-Esnault, N; Vacelet, J; Christen, R

    1992-01-01

    Sequences from the 5' end terminal part of 28S ribosomal RNA were obtained and compared for 22 animals belonging to all diploblastic phyla and for a large number of representatives of triploblastic Metazoa and protists. Phylogenetic analyses undertaken using different methods showed deep radiations of phyla such as Ctenophora, Cnidaria and Placozoa but also for groups of Porifera of low taxonomic rank. Short internodes between these radiations suggested an early rapid diversification of diploblasts. A long internal branch preceding the diversification of all triploblasts analyzed could be explained either by a long period with a single ancestor or by the extinction of the earliest triploblastic radiations. Finally some unexpected relationships were revealed among Porifera.

  12. Involved Node Radiation Therapy: An Effective Alternative in Early-Stage Hodgkin Lymphoma

    SciTech Connect

    Maraldo, Maja V.; Aznar, Marianne C.; Vogelius, Ivan R.; Petersen, Peter M.; Specht, Lena

    2013-03-15

    Purpose: The involved node radiation therapy (INRT) strategy was introduced for patients with Hodgkin lymphoma (HL) to reduce the risk of late effects. With INRT, only the originally involved lymph nodes are irradiated. We present treatment outcome in a retrospective analysis using this strategy in a cohort of 97 clinical stage I-II HL patients. Methods and Materials: Patients were staged with positron emission tomography/computed tomography scans, treated with adriamycin, bleomycin, vinblastine, and dacarbazine chemotherapy, and given INRT (prechemotherapy involved nodes to 30 Gy, residual masses to 36 Gy). Patients attended regular follow-up visits until 5 years after therapy. Results: The 4-year freedom from disease progression was 96.4% (95% confidence interval: 92.4%-100.4%), median follow-up of 50 months (range: 4-71 months). Three relapses occurred: 2 within the previous radiation field, and 1 in a previously uninvolved region. The 4-year overall survival was 94% (95% confidence interval: 88.8%-99.1%), median follow-up of 58 months (range: 4-91 months). Early radiation therapy toxicity was limited to grade 1 (23.4%) and grade 2 (13.8%). During follow-up, 8 patients died, none from HL, 7 malignancies were diagnosed, and 5 patients developed heart disease. Conclusions: INRT offers excellent tumor control and represents an effective alternative to more extended radiation therapy in the combined modality treatment for early-stage HL.

  13. Investigating the Sensitivity of Arctic Sea Ice to Variability in Early Summer Cloud Radiative Effect

    NASA Astrophysics Data System (ADS)

    King, M. D.

    2015-12-01

    Arctic sea ice is a highly sensitive and integral component of the climate system. The observed decline of sea ice in recent decades has affected Arctic ecosystems, transportation, and atmospheric processes. For these reasons, the development of skillful seasonal model predictions is essential, particularly for the early autumn when Arctic ice retreats to its minimum extent. However, a high degree of temporal and spatial variability has made sea ice predictions challenging. Arctic clouds become a large source of this variability by altering the amount of insolation and longwave radiation that is received at the surface. The goal of this research is to identify the predictive value of early summer cloud radiative effect (CRE) on autumnal sea ice extent. Absorbed solar radiation at the surface is most sensitive to cloud cover and composition during months of peak solar insolation, and may precondition the melting momentum of the sea ice in the subsequent months. Satellite data products, such as CERES, are used to investigate trends in cloud cover and radiative properties over the entire Arctic, as well as in several specific Arctic regions. This data, along with satellite sea ice concentration products, will be used to investigate the sensitivity of autumnal sea ice extent to changes in CRE throughout the melt season. The influence of relevant, larger-scale climate oscillations on atmospheric regimes and resulting cloud distribution will also be given consideration.

  14. Early development and characterization of a DNA-based radiation dosimeter

    NASA Astrophysics Data System (ADS)

    Avarmaa, Kirsten A.

    It is the priority of first responders to minimize damage to persons and infrastructure in the case of a nuclear emergency due to an accident or deliberate terrorist attack -- if this emergency includes a radioactive hazard, first responders require a simple-to-use, accurate and complete dosimeter for radiation protection purposes in order to minimize the health risk to these individuals and the general population at large. This work consists of the early evaluation of the design and performance of a biologically relevant dosimeter which uses DNA material that can respond to the radiation of any particle type. The construct consists of fluorescently tagged strands of DNA. The signalling components of this dosimeter are also investigated for their sensitivity to radiation damage and light exposure. The dual-labelled dosimeter that is evaluated in this work gave a measurable response to gamma radiation at dose levels of 10 Gy for the given detector design and experimental setup. Further testing outside of this work confirmed this finding and indicated a working range of 100 mGy to 10 Gy using a custom-built fluorimeter as part of a larger CRTI initiative. Characterization of the chromatic components of the dosimeter showed that photobleaching is not expected to have an effect on dosimeter performance, but that radiation can damage the non-DNA signalling components at higher dose levels, although this damage is minimal at lower doses over the expected operating ranges. This work therefore describes the early steps in the quantification of the behaviour of the DNA dosimeter as a potential biologically-based device to measure radiation dose.

  15. Activation of Protease Activated Receptor 2 by Exogenous Agonist Exacerbates Early Radiation Injury in Rat Intestine

    SciTech Connect

    Wang Junru; Boerma, Marjan; Kulkarni, Ashwini; Hollenberg, Morley D.; Hauer-Jensen, Martin

    2010-07-15

    Purpose: Protease-activated receptor-2 (PAR{sub 2}) is highly expressed throughout the gut and regulates the inflammatory, mitogenic, fibroproliferative, and nociceptive responses to injury. PAR{sub 2} is strikingly upregulated and exhibits increased activation in response to intestinal irradiation. We examined the mechanistic significance of radiation enteropathy development by assessing the effect of exogenous PAR{sub 2} activation. Methods and Materials: Rat small bowel was exposed to localized single-dose radiation (16.5 Gy). The PAR{sub 2} agonist (2-furoyl-LIGRLO-NH{sub 2}) or vehicle was injected intraperitoneally daily for 3 days before irradiation (before), for 7 days after irradiation (after), or both 3 days before and 7 days after irradiation (before-after). Early and delayed radiation enteropathy was assessed at 2 and 26 weeks after irradiation using quantitative histologic examination, morphometry, and immunohistochemical analysis. Results: The PAR{sub 2} agonist did not elicit changes in the unirradiated (shielded) intestine. In contrast, in the irradiated intestine procured 2 weeks after irradiation, administration of the PAR{sub 2} agonist was associated with more severe mucosal injury and increased intestinal wall thickness in all three treatment groups (p <.05) compared with the vehicle-treated controls. The PAR{sub 2} agonist also exacerbated the radiation injury score, serosal thickening, and mucosal inflammation (p <.05) in the before and before-after groups. The short-term exogenous activation of PAR{sub 2} did not affect radiation-induced intestinal injury at 26 weeks. Conclusion: The results of the present study support a role for PAR{sub 2} activation in the pathogenesis of early radiation-induced intestinal injury. Pharmacologic PAR{sub 2} antagonists might have the potential to reduce the intestinal side effects of radiotherapy and/or as countermeasures in radiologic accidents or terrorism scenarios.

  16. The assessment of cytotoxic T cell and natural killer cells activity in residents of high and ordinary background radiation areas of Ramsar-Iran.

    PubMed

    Borzoueisileh, Sajad; Monfared, Ali Shabestani; Abediankenari, Saeid; Mostafazadeh, Amrollah

    2013-01-01

    The effective radiation dose of human from natural sources is about 2.4 mSv/y and the dose limit for radiation workers is 20 mSv/y. Ramsar, a city in Iran, has been the subject of concern in the last forty years for a high level of radiation measured in some spots as high as 260 mSv/y. Carcinogenesis is one of the most studied effects of radiation especially in high doses. Recent studies showed that the high level of natural radiation received by inhabitants of this area, paradoxically don't have significant health effect. Natural killer (NK) cells and cytotoxic T cells are the most important cells in tumor immune surveillance and CD107a is a widely expressed intracellular protein located in the lysosomal/endosomal membrane. CD107a transiently located on the cell membrane can be used as a marker of CD8 + T cell degranulation following stimulation. It is also expressed, to a lower extent, on activated NK cells. In this study, 60 healthy people were selected randomly and their consent obtained and confounding factors such as sex, age, life-styles was matched then the count of activated NK and CD8 + cells was compared in high and normal background radiation areas inhabitants of Ramsar. After filling the questionnaire and measurement of background radiation, blood samples of 30 healthy people from each region were analyzed immediately by means of flowcytometry. The leukocytes and their subsets were not significantly different between two groups and the count of active cells was higher in control group. The result shows that the changes in immune system occur due to radiation and maybe it is as a result of higher radiosensitivity of activated cells. PMID:23531635

  17. Radiation protection program for early detection of breast cancer in a mammography facility

    NASA Astrophysics Data System (ADS)

    Villagomez Casimiro, Mariana; Ruiz Trejo, Cesar; Espejo Fonseca, Ruby

    2014-11-01

    Mammography is the best tool for early detection of Breast Cancer. In this diagnostic radiology modality it is necessary to establish the criteria to ensure the proper use and operation of the equipment used to obtain mammographic images in order to contribute to the safe use of ionizing radiation. The aim of the work was to implement at FUCAM-AC the radiation protection program which must be established for patients and radiation workers according to Mexican standards [1-4]. To achieve this goal, radiation protection and quality control manuals were elaborated [5]. Furthermore, a quality control program (QCP) in the mammography systems (analog/digital), darkroom included, has been implemented. Daily sensitometry, non-variability of the image quality, visualizing artifacts, revision of the equipment mechanical stability, compression force and analysis of repetition studies are some of the QCP routine tests that must be performed by radiological technicians of this institution as a set of actions to ensure the protection of patients. Image quality and patients dose assessment were performed on 4 analog equipment installed in 2 mobile units. In relation to dose assessment, all equipment passed the acceptance criteria (<3 mGy per projection). The image quality test showed that most images (70%)- presented artifacts. A brief summary of the results of quality control tests applied to the equipment and film processor are presented. To maintain an adequate level of quality and safety at FUCAM-AC is necessary that the proposed radiation protection program in this work is applied.

  18. Radiation protection program for early detection of breast cancer in a mammography facility

    SciTech Connect

    Mariana, Villagomez Casimiro E-mail: cesar@fisica.unam.mx; Cesar, Ruiz Trejo E-mail: cesar@fisica.unam.mx; Ruby, Espejo Fonseca

    2014-11-07

    Mammography is the best tool for early detection of Breast Cancer. In this diagnostic radiology modality it is necessary to establish the criteria to ensure the proper use and operation of the equipment used to obtain mammographic images in order to contribute to the safe use of ionizing radiation. The aim of the work was to implement at FUCAM-AC the radiation protection program which must be established for patients and radiation workers according to Mexican standards [1–4]. To achieve this goal, radiation protection and quality control manuals were elaborated [5]. Furthermore, a quality control program (QCP) in the mammography systems (analog/digital), darkroom included, has been implemented. Daily sensitometry, non-variability of the image quality, visualizing artifacts, revision of the equipment mechanical stability, compression force and analysis of repetition studies are some of the QCP routine tests that must be performed by radiological technicians of this institution as a set of actions to ensure the protection of patients. Image quality and patients dose assessment were performed on 4 analog equipment installed in 2 mobile units. In relation to dose assessment, all equipment passed the acceptance criteria (<3 mGy per projection). The image quality test showed that most images (70%)– presented artifacts. A brief summary of the results of quality control tests applied to the equipment and film processor are presented. To maintain an adequate level of quality and safety at FUCAM-AC is necessary that the proposed radiation protection program in this work is applied.

  19. Effect of ozone oxidative preconditioning in preventing early radiation-induced lung injury in rats.

    PubMed

    Bakkal, B H; Gultekin, F A; Guven, B; Turkcu, U O; Bektas, S; Can, M

    2013-09-01

    Ionizing radiation causes its biological effects mainly through oxidative damage induced by reactive oxygen species. Previous studies showed that ozone oxidative preconditioning attenuated pathophysiological events mediated by reactive oxygen species. As inhalation of ozone induces lung injury, the aim of this study was to examine whether ozone oxidative preconditioning potentiates or attenuates the effects of irradiation on the lung. Rats were subjected to total body irradiation, with or without treatment with ozone oxidative preconditioning (0.72 mg/kg). Serum proinflammatory cytokine levels, oxidative damage markers, and histopathological analysis were compared at 6 and 72 h after total body irradiation. Irradiation significantly increased lung malondialdehyde levels as an end-product of lipoperoxidation. Irradiation also significantly decreased lung superoxide dismutase activity, which is an indicator of the generation of oxidative stress and an early protective response to oxidative damage. Ozone oxidative preconditioning plus irradiation significantly decreased malondialdehyde levels and increased the activity of superoxide dismutase, which might indicate protection of the lung from radiation-induced lung injury. Serum tumor necrosis factor alpha and interleukin-1 beta levels, which increased significantly following total body irradiation, were decreased with ozone oxidative preconditioning. Moreover, ozone oxidative preconditioning was able to ameliorate radiation-induced lung injury assessed by histopathological evaluation. In conclusion, ozone oxidative preconditioning, repeated low-dose intraperitoneal administration of ozone, did not exacerbate radiation-induced lung injury, and, on the contrary, it provided protection against radiation-induced lung damage.

  20. Early parathyroid hormone laboratory abnormalities related to therapeutic radiation of neck: an Egyptian experience.

    PubMed

    Aboelnaga, Mohamed M; Aboelnaga, Engy M

    2015-05-01

    The effect of neck radiation on parathyroid hormone (PTH) is studied on concern as late effect of radiotherapy for benign or malignant diseases. However, the early effect on PTH is still in debate and need further evaluations. We aimed, in our study, to assess early effect of neck radiation on PTH, and related calcium and phosphorus levels. Patients diagnosed with breast or head and neck cancer who planned to received radiotherapy to neck as a definite or a part of their treatment enrolled in this prospective single-arm study from June 2012 to June 2013. Laboratory assessment of PTH, serum calcium, phosphorus and albumin was obtained before starting radiotherapy, 3 weeks and 3 months after radiation. Fifty-two patients included 24 (46.2 %) males and 28(53.8 %) females. Median age of diagnosis was 55 years. Thirty-six patients had head and neck cancer, while 16 patients were diagnosed as breast cancer. The difference in PTH and calcium levels before and after radiotherapy was statistically significant (P = 0.014 and P = 0.001 for 3 weeks and P = 0.015 and P = 0.004 for 3 months, respectively); even after correction of calcium level according to albumin level, the same results were obtained, while there was no significant difference in their levels after 3 weeks in comparison with 3 months after radiotherapy. The variation of level of phosphorus was not significant. PTH and calcium can be affected early with neck radiation, so follow-up of calcium and PTH level is mandatory for cases that will receive neck radiotherapy. PMID:25904502

  1. Combined radiation and burn injury results in exaggerated early pulmonary inflammation

    PubMed Central

    Palmer, Jessica L.; Deburghgraeve, Cory R.; Bird, Melanie D.; Hauer-Jensen, Martin; Chen, Michael M.; Yong, Sherri; Kovacs, Elizabeth J.

    2014-01-01

    Events such as a nuclear meltdown accident or nuclear attack have potential for severe radiation injuries. Radiation injury frequently occurs in combination with other forms of trauma, most often burns. Thus far, combined injury studies have focused mainly on skin wound healing and damage to the gut. Since both radiation exposure and remote burn have pulmonary consequences, we examined the early effects of combined injury on the lung. C57BL/6 male mice were subjected to 5 Gy of total body irradiation followed by a 15% total body surface area scald burn. Lungs from surviving animals were examined for evidence of inflammation and pneumonitis. At 48 hours post-injury, pathology of the lungs from combined injury mice showed greater inflammation compared to all other treatment groups, with marked red blood cell and leukocyte congestion of the pulmonary vasculature. There was excessive leukocyte accumulation, primarily neutrophils, in the vasculature and interstitium, with occasional cells in the alveolar space. At 24 and 48 hours post-injury, myeloperoxidase levels in lungs of mice given combined injury were elevated compared to all other treatment groups (p<0.01), confirming histological evidence of neutrophil accumulation. Pulmonary levels of the neutrophil chemoattractant KC (CXCL1) were 3 times above that of either injury alone (p<0.05). Further, monocyte chemotactic protein-1 (MCP-1, CCL2) was increased 2-fold and 3-fold compared to burn injury or radiation injury, respectively (p<0.05). Together, these data suggest that combined radiation and burn injury augments early pulmonary congestion and inflammation.. Currently, countermeasures for this unique type of injury are extremely limited. Further research is needed to elucidate the mechanisms behind the synergistic effects of combined injury in order to develop appropriate treatments. PMID:23899376

  2. The Cosmic Background Explorer.

    ERIC Educational Resources Information Center

    Gulkis, Samuel; And Others

    1990-01-01

    Outlines the Cosmic Background Explorer (COBE) mission to measure celestial radiation. Describes the instruments used and experiments involving differential microwave radiometers, and a far infrared absolute spectrophotometer. (YP)

  3. Biophysical modelling of early and delayed radiation damage at chromosome level

    NASA Astrophysics Data System (ADS)

    Andreev, S.; Eidelman, Y.

    Exposure by ionising radiation increases cancer risk in human population Cancer is thought to originate from an altered expression of certain number of specific genes It is now widely recognised that chromosome aberrations CA are involved in stable change in expression of genes by gain or loss of their functions Thus CA can contribute to initiation or progression of cancer Therefore understanding mechanisms of CA formation in the course of cancer development might be valuable tool for quantification and prognosis of different stages of radiation carcinogenesis Early CA are defined as aberrations induced in first post-irradiation mitotic cycle The present work describes the original biophysical technique for early CA modelling It includes the following simulation steps the ionising particle track structure the structural organisation of all chromosomes in G 0 G 1 cell nucleus spatial distribution of radiation induced DNA double-strand breaks dsb within chromosomes dsb rejoining and misrejoining modelling cell cycle taking into account mitotic delay which results in complex time dependence of aberrant cells in first mitosis The results on prediction of dose-response curves for simple and complex CA measured in cells undergoing first division cycle are presented in comparison with recent experimental data There is increasing evidence that CA are also observed in descendents of irradiated cells many generations after direct DNA damage These delayed CA or chromosome instability CI are thought to be a manifestation of genome

  4. Hidden Gains: Effects of Early U.S. Compulsory Schooling Laws on Attendance and Attainment by Social Background

    ERIC Educational Resources Information Center

    Rauscher, Emily

    2014-01-01

    Research on early compulsory schooling laws finds minimal effects on attendance but fails to investigate heterogeneous effects. Similarly, research proposes limited contexts in which expansion policies can increase equality but has difficulty separating policy and cohort effects. Capitalizing on within-country variation in timing of early…

  5. The Origin and Early Radiation of Archosauriforms: Integrating the Skeletal and Footprint Record.

    PubMed

    Bernardi, Massimo; Klein, Hendrik; Petti, Fabio Massimo; Ezcurra, Martín D

    2015-01-01

    We present a holistic approach to the study of early archosauriform evolution by integrating body and track records. The ichnological record supports a Late Permian-Early Triassic radiation of archosauriforms not well documented by skeletal material, and new footprints from the Upper Permian of the southern Alps (Italy) provide evidence for a diversity not yet sampled by body fossils. The integrative study of body fossil and footprint data supports the hypothesis that archosauriforms had already undergone substantial taxonomic diversification by the Late Permian and that by the Early Triassic archosauromorphs attained a broad geographical distribution over most parts of Pangea. Analysis of body size, as deduced from track size, suggests that archosauriform average body size did not change significantly from the Late Permian to the Early Triassic. A survey of facies yielding both skeletal and track record indicate an ecological preference for inland fluvial (lacustrine) environments for early archosauromorphs. Finally, although more data is needed, Late Permian chirotheriid imprints suggest a shift from sprawling to erect posture in archosauriforms before the end-Permian mass extinction event. We highlight the importance of approaching palaeobiological questions by using all available sources of data, specifically through integrating the body and track fossil record. PMID:26083612

  6. The Origin and Early Radiation of Archosauriforms: Integrating the Skeletal and Footprint Record.

    PubMed

    Bernardi, Massimo; Klein, Hendrik; Petti, Fabio Massimo; Ezcurra, Martín D

    2015-01-01

    We present a holistic approach to the study of early archosauriform evolution by integrating body and track records. The ichnological record supports a Late Permian-Early Triassic radiation of archosauriforms not well documented by skeletal material, and new footprints from the Upper Permian of the southern Alps (Italy) provide evidence for a diversity not yet sampled by body fossils. The integrative study of body fossil and footprint data supports the hypothesis that archosauriforms had already undergone substantial taxonomic diversification by the Late Permian and that by the Early Triassic archosauromorphs attained a broad geographical distribution over most parts of Pangea. Analysis of body size, as deduced from track size, suggests that archosauriform average body size did not change significantly from the Late Permian to the Early Triassic. A survey of facies yielding both skeletal and track record indicate an ecological preference for inland fluvial (lacustrine) environments for early archosauromorphs. Finally, although more data is needed, Late Permian chirotheriid imprints suggest a shift from sprawling to erect posture in archosauriforms before the end-Permian mass extinction event. We highlight the importance of approaching palaeobiological questions by using all available sources of data, specifically through integrating the body and track fossil record.

  7. The Origin and Early Radiation of Archosauriforms: Integrating the Skeletal and Footprint Record

    PubMed Central

    Bernardi, Massimo; Klein, Hendrik; Petti, Fabio Massimo; Ezcurra, Martín D.

    2015-01-01

    We present a holistic approach to the study of early archosauriform evolution by integrating body and track records. The ichnological record supports a Late Permian–Early Triassic radiation of archosauriforms not well documented by skeletal material, and new footprints from the Upper Permian of the southern Alps (Italy) provide evidence for a diversity not yet sampled by body fossils. The integrative study of body fossil and footprint data supports the hypothesis that archosauriforms had already undergone substantial taxonomic diversification by the Late Permian and that by the Early Triassic archosauromorphs attained a broad geographical distribution over most parts of Pangea. Analysis of body size, as deduced from track size, suggests that archosauriform average body size did not change significantly from the Late Permian to the Early Triassic. A survey of facies yielding both skeletal and track record indicate an ecological preference for inland fluvial (lacustrine) environments for early archosauromorphs. Finally, although more data is needed, Late Permian chirotheriid imprints suggest a shift from sprawling to erect posture in archosauriforms before the end-Permian mass extinction event. We highlight the importance of approaching palaeobiological questions by using all available sources of data, specifically through integrating the body and track fossil record. PMID:26083612

  8. Characterization of early pathogenesis in the SOD1G93A mouse model of ALS: part I, background and methods

    PubMed Central

    Vinsant, Sharon; Mansfield, Carol; Jimenez-Moreno, Ramon; Del Gaizo Moore, Victoria; Yoshikawa, Masaaki; Hampton, Thomas G; Prevette, David; Caress, James; Oppenheim, Ronald W; Milligan, Carol

    2013-01-01

    Charcot first described amyotrophic lateral sclerosis (ALS) in 1869; however, its causes remain largely unknown and effective, long-term treatment strategies are not available. The first mouse model of ALS was developed after the identification of mutations in the superoxide dismutase 1 (SOD1) gene in 1993, and accordingly most of our knowledge of the etiology and pathogenesis of the disease comes from studies carried out using this animal model. Although numerous preclinical trials have been conducted in the mutant SOD1 mouse models, the results have been disappointing because they did not positively translate to clinical trials. One explanation may be that current understanding of when and where pathogenesis begins is insufficient to accurately guide preclinical trials. Further characterization of these early events may provide insight into disease onset, help in the discovery of presymptomatic diagnostic disease markers, and identify novel therapeutic targets. Here, we describe the rationale, approach, and methods for our extensive analysis of early changes that included an ultrastructural examination of central and peripheral components of the neuromuscular system in the SOD1G93A mouse and correlated these alterations with early muscle denervation, motor dysfunction, and motoneuron death. We also provide a discussion of published work to review what is known regarding early pathology in the SOD1 mouse model of ALS. The significance of this work is that we have examined early pathology simultaneously in both the spinal cord and peripheral neuromuscular system, and the results are presented in the companion paper (Part II, Results and Discussion). Our results provide evidence as to why a thorough characterization of animal models throughout the life span is critical for a strong foundation to design preclinical trials that may produce meaningful results. PMID:24381807

  9. Early Cognitive Outcomes Following Proton Radiation in Pediatric Patients With Brain and Central Nervous System Tumors

    SciTech Connect

    Pulsifer, Margaret B.; Sethi, Roshan V.; Kuhlthau, Karen A.; MacDonald, Shannon M.; Tarbell, Nancy J.; Yock, Torunn I.

    2015-10-01

    Purpose: To report, from a longitudinal study, cognitive outcome in pediatric patients treated with proton radiation therapy (PRT) for central nervous system (CNS) tumors. Methods and Materials: Sixty patients receiving PRT for medulloblastoma (38.3%), gliomas (18.3%), craniopharyngioma (15.0%), ependymoma (11.7%), and other CNS tumors (16.7%) were administered age-appropriate measures of cognitive abilities at or near PRT initiation (baseline) and afterward (follow-up). Patients were aged ≥6 years at baseline to ensure consistency in neurocognitive measures. Results: Mean age was 12.3 years at baseline; mean follow-up interval was 2.5 years. Treatment included prior surgical resection (76.7%) and chemotherapy (61.7%). Proton radiation therapy included craniospinal irradiation (46.7%) and partial brain radiation (53.3%). At baseline, mean Wechsler Full Scale IQ was 104.6; means of all 4 Index scores were also in the average range. At follow-up, no significant change was observed in mean Wechsler Full Scale IQ, Verbal Comprehension, Perceptual Reasoning/Organization, or Working Memory. However, Processing Speed scores declined significantly (mean 5.2 points), with a significantly greater decline for subjects aged <12 years at baseline and those with the highest baseline scores. Cognitive outcome was not significantly related to gender, extent of radiation, radiation dose, tumor location, histology, socioeconomic status, chemotherapy, or history of surgical resection. Conclusions: Early cognitive outcomes after PRT for pediatric CNS tumors are encouraging, compared with published outcomes from photon radiation therapy.

  10. Evidence of late Gelasian dispersal of African fauna at Coste San Giacomo (Anagni Basin, central Italy): Early Pleistocene environments and the background of early human occupation in Europe

    NASA Astrophysics Data System (ADS)

    Bellucci, L.; Bona, F.; Corrado, P.; Magri, D.; Mazzini, I.; Parenti, F.; Scardia, G.; Sardella, R.

    2014-07-01

    Since the late 70s, the Early Pleistocene (Gelasian) site of Coste San Giacomo (Anagni Basin, central Italy) has been known amongst palaeontologists for its diverse vertebrate fauna. During the last 5 years, new excavations and the drilling of a 46-m-deep core have provided novel pieces of information. Palaeomagnetic data, pollen and small vertebrates analyses are presented here for the first time and combined with the updated list of the large vertebrates and ostracod analysis in a multidisciplinary perspective. Large and small mammals, pollen and ostracod analyses have allowed an integrated palaeoenvironmental reconstruction of the sedimentary sequence, depicting the evolution of the alluvial plain in the surrounding landscape. Moreover, magnetostratigraphy, pollen and small mammal biochronological data have confirmed the position of the Coste San Giacomo Faunal Unit, focusing the possible age of the mammal assemblage around 2.1 Ma, in a reversed phase before the base of the Olduvai chron. In particular, the occurrence of the large vole Mimomys pliocaenicus has important biochronological significance. The Coste San Giacomo site offers a unique opportunity to investigate the faunal and environmental changes that occurred in Mediterranean Europe during the Early Pleistocene, coinciding with major climatic changes at a global scale. The occurrence of taxa such as Hippopotamus sp. in the assemblage provides evidence of early dispersal events of African taxa prior to the early Homo diffusion into Europe.

  11. How Does Early Childhood Care and Education Affect Cognitive Development? An International Review of the Effects of Early Interventions for Children from Different Social Backgrounds

    ERIC Educational Resources Information Center

    Burger, Kaspar

    2010-01-01

    A number of authors have investigated the impact of early childhood education and care programs on the development of children. Often they have focused on the effects on children from socio-economically disadvantaged families. To assess the effects of various preschool programs on cognitive development, recent key studies were reviewed. In…

  12. Radiation exposure and disease questionnaires of early entrants after the Hiroshima bombing.

    PubMed

    Imanaka, Tetsuji; Endo, Satoru; Kawano, Noriyuki; Tanaka, Kenichi

    2012-03-01

    It is popularly known that people who entered into the ground-zero area shortly after the atomic bombings in Hiroshima and Nagasaki suffered from various syndromes similar to acute radiation effects. External exposures from neutron-induced radionuclides in soil have recently been reassessed based on DS02 calculations as functions of both distance from the hypocentres and elapsed time after the explosions. Significant exposure due to induced radiation can be determined for those who entered the area within 1000 m from the hypocentres shortly after the bombing. Although it was impossible to track the action of each of the survivors over the days or weeks following the bombings in order to make reliable dose estimates for their exposures to soil activation or fallout, four individuals among those early entrants were investigated here to describe useful information of what happened shortly after the bombing.

  13. Early growth dynamical implications for the steerability of stratospheric solar radiation management via sulfur aerosol particles

    NASA Astrophysics Data System (ADS)

    Benduhn, François; Schallock, Jennifer; Lawrence, Mark G.

    2016-09-01

    Aerosol growth dynamics may have implications for the steerability of stratospheric solar radiation management via sulfur particles. This paper derives a set of critical initial growth conditions that are analyzed as a function of two key parameters: the initial concentration of the injected sulfuric acid and its dilution rate with the surrounding air. Based upon this analysis, early aerosol growth dynamical regimes may be defined and classified in terms of their likelihood to serve as candidates for the controlled generation of a radiatively effective aerosol. Our results indicate that the regime that fulfills all critical conditions would require that airplane turbines be used to provide sufficient turbulence. The regime's parameter space is narrow and related to steep gradients, thus pointing to potential fine tuning requirements. More research, development, and testing would be required to refine our findings and determine their global-scale implications.

  14. Radiation exposure and disease questionnaires of early entrants after the Hiroshima bombing.

    PubMed

    Imanaka, Tetsuji; Endo, Satoru; Kawano, Noriyuki; Tanaka, Kenichi

    2012-03-01

    It is popularly known that people who entered into the ground-zero area shortly after the atomic bombings in Hiroshima and Nagasaki suffered from various syndromes similar to acute radiation effects. External exposures from neutron-induced radionuclides in soil have recently been reassessed based on DS02 calculations as functions of both distance from the hypocentres and elapsed time after the explosions. Significant exposure due to induced radiation can be determined for those who entered the area within 1000 m from the hypocentres shortly after the bombing. Although it was impossible to track the action of each of the survivors over the days or weeks following the bombings in order to make reliable dose estimates for their exposures to soil activation or fallout, four individuals among those early entrants were investigated here to describe useful information of what happened shortly after the bombing. PMID:21914640

  15. Scientific background of contemporary approach in the priority areas of medical science in the field of radiation medicine and radiobiology.

    PubMed

    Chumak, A A; Medvedovska, N V; Ovsannikova, L M

    2013-01-01

    OBJECTIVE. To analyze the results of scientific research on the problems of radiation medicine and radiobiology for the further outlining of the priority fields of research in this area. MATERIALS. Perspective plans and annual summary of research (R & D) NAMS of Ukraine, interim and final reports on implementation of research, reports on the activities of institutions, thematic scientific publications. METHODS. Semantic and content analysis, bibliometry, historical and logical analysis. RESULTS. The definition of major oncological risks of radiation effects, study of radiation risks of morbidity and mortality from cardiovascular and cerebrovascular diseases, cognitive effects and cataract in liquidators of the Chornobyl nuclear power plant accident, study of transgenic effects of the brain irradiation, other organs and systems in various stages of ontogenesis in exposed in utero, in offspring of exposed parents; study of the effects of occupational exposure were recognized as perspective and requiring further research in radiation medicine. CONCLUSION. Issues of NNCRM scientific activity are consistent with priority areas of research in Ukraine defined by the Law "On priority directions of science and technology", namely, aimed at substantiating of the development and preservation of human potential, aimed at the creation of modern technologies on prevention and treatment of most common diseases.

  16. Early exposure to ultraviolet-B radiation decreases immune function later in life

    PubMed Central

    Ceccato, Emma; Cramp, Rebecca L.; Seebacher, Frank; Franklin, Craig E.

    2016-01-01

    Amphibians have declined dramatically worldwide. Many of these declines are occurring in areas where no obvious anthropogenic stressors are present. It is proposed that in these areas, environmental factors such as elevated solar ultraviolet-B (UV-B) radiation could be responsible. Ultraviolet-B levels have increased in many parts of the world as a consequence of the anthropogenic destruction of the ozone layer. Amphibian tadpoles are particularly sensitive to the damaging effects of UV-B radiation, with exposure disrupting growth and fitness in many species. Given that UV-B can disrupt immune function in other animals, we tested the hypothesis that early UV-B exposure suppresses the immune responses of amphibian tadpoles and subsequent juvenile frogs. We exposed Limnodynastes peronii tadpoles to sublethal levels of UV-B radiation for 6 weeks after hatching, then examined indices of immune function in both the tadpoles and the subsequent metamorphs. There was no significant effect of UV-B on tadpole leucocyte counts or on their response to an acute antigen (phytohaemagglutinin) challenge. However, early UV-B exposure resulted in a significant reduction in both metamorph leucocyte abundance and their response to an acute phytohaemagglutinin challenge. These data demonstrate that early UV-B exposure can have carry-over effects on later life-history traits even if the applied stressor has no immediately discernible effect. These findings have important implications for our understanding of the effects of UV-B exposure on amphibian health and susceptibility to diseases such as chytridiomycosis. PMID:27668081

  17. Early exposure to ultraviolet-B radiation decreases immune function later in life.

    PubMed

    Ceccato, Emma; Cramp, Rebecca L; Seebacher, Frank; Franklin, Craig E

    2016-01-01

    Amphibians have declined dramatically worldwide. Many of these declines are occurring in areas where no obvious anthropogenic stressors are present. It is proposed that in these areas, environmental factors such as elevated solar ultraviolet-B (UV-B) radiation could be responsible. Ultraviolet-B levels have increased in many parts of the world as a consequence of the anthropogenic destruction of the ozone layer. Amphibian tadpoles are particularly sensitive to the damaging effects of UV-B radiation, with exposure disrupting growth and fitness in many species. Given that UV-B can disrupt immune function in other animals, we tested the hypothesis that early UV-B exposure suppresses the immune responses of amphibian tadpoles and subsequent juvenile frogs. We exposed Limnodynastes peronii tadpoles to sublethal levels of UV-B radiation for 6 weeks after hatching, then examined indices of immune function in both the tadpoles and the subsequent metamorphs. There was no significant effect of UV-B on tadpole leucocyte counts or on their response to an acute antigen (phytohaemagglutinin) challenge. However, early UV-B exposure resulted in a significant reduction in both metamorph leucocyte abundance and their response to an acute phytohaemagglutinin challenge. These data demonstrate that early UV-B exposure can have carry-over effects on later life-history traits even if the applied stressor has no immediately discernible effect. These findings have important implications for our understanding of the effects of UV-B exposure on amphibian health and susceptibility to diseases such as chytridiomycosis. PMID:27668081

  18. Early exposure to ultraviolet-B radiation decreases immune function later in life.

    PubMed

    Ceccato, Emma; Cramp, Rebecca L; Seebacher, Frank; Franklin, Craig E

    2016-01-01

    Amphibians have declined dramatically worldwide. Many of these declines are occurring in areas where no obvious anthropogenic stressors are present. It is proposed that in these areas, environmental factors such as elevated solar ultraviolet-B (UV-B) radiation could be responsible. Ultraviolet-B levels have increased in many parts of the world as a consequence of the anthropogenic destruction of the ozone layer. Amphibian tadpoles are particularly sensitive to the damaging effects of UV-B radiation, with exposure disrupting growth and fitness in many species. Given that UV-B can disrupt immune function in other animals, we tested the hypothesis that early UV-B exposure suppresses the immune responses of amphibian tadpoles and subsequent juvenile frogs. We exposed Limnodynastes peronii tadpoles to sublethal levels of UV-B radiation for 6 weeks after hatching, then examined indices of immune function in both the tadpoles and the subsequent metamorphs. There was no significant effect of UV-B on tadpole leucocyte counts or on their response to an acute antigen (phytohaemagglutinin) challenge. However, early UV-B exposure resulted in a significant reduction in both metamorph leucocyte abundance and their response to an acute phytohaemagglutinin challenge. These data demonstrate that early UV-B exposure can have carry-over effects on later life-history traits even if the applied stressor has no immediately discernible effect. These findings have important implications for our understanding of the effects of UV-B exposure on amphibian health and susceptibility to diseases such as chytridiomycosis.

  19. Early exposure to ultraviolet-B radiation decreases immune function later in life

    PubMed Central

    Ceccato, Emma; Cramp, Rebecca L.; Seebacher, Frank; Franklin, Craig E.

    2016-01-01

    Amphibians have declined dramatically worldwide. Many of these declines are occurring in areas where no obvious anthropogenic stressors are present. It is proposed that in these areas, environmental factors such as elevated solar ultraviolet-B (UV-B) radiation could be responsible. Ultraviolet-B levels have increased in many parts of the world as a consequence of the anthropogenic destruction of the ozone layer. Amphibian tadpoles are particularly sensitive to the damaging effects of UV-B radiation, with exposure disrupting growth and fitness in many species. Given that UV-B can disrupt immune function in other animals, we tested the hypothesis that early UV-B exposure suppresses the immune responses of amphibian tadpoles and subsequent juvenile frogs. We exposed Limnodynastes peronii tadpoles to sublethal levels of UV-B radiation for 6 weeks after hatching, then examined indices of immune function in both the tadpoles and the subsequent metamorphs. There was no significant effect of UV-B on tadpole leucocyte counts or on their response to an acute antigen (phytohaemagglutinin) challenge. However, early UV-B exposure resulted in a significant reduction in both metamorph leucocyte abundance and their response to an acute phytohaemagglutinin challenge. These data demonstrate that early UV-B exposure can have carry-over effects on later life-history traits even if the applied stressor has no immediately discernible effect. These findings have important implications for our understanding of the effects of UV-B exposure on amphibian health and susceptibility to diseases such as chytridiomycosis.

  20. Expression of immediate early genes after treatment of human astrocytoma cells with radiation and taxol

    SciTech Connect

    Gubits, R.M.; Geard, C.R.; Schiff, P.B.

    1993-10-20

    The promising chemotherapeutic agent, taxol, has been shown to sensitize the G18 line of human astrocytoma cells to ionizing radiation. The present studies were performed to identify specific changes in gene expression associated with this altered sensitivity. The products of immediate early genes, which are induced transiently in cells in response to a variety of treatments, including growth factors, neurotransmitters, and irradiation with UV light or X rays, are thought to initiate a cascade of genetic responses to alterations in cellular environment. The present results demonstrate a dramatic attenuation in one immediate early gene response in association with a treatment that enhances radiosensitivity in a refractory human brain tumor line. 22 refs., 5 figs., 1 tab.

  1. Radiation-induced breast cancer: the question of early breast cancer screening in Hodgkin's lymphoma survivors.

    PubMed

    Hilal, Talal; Rudy, David W

    2016-02-01

    Chest irradiation is associated with numerous early and late complications that arise from ionizing radiation-induced damage to cellular structures within the field of therapy. In patients exposed to chest irradiation at an early age as part of the treatment of childhood cancer, specifically Hodgkin's lymphoma, the increased risk of breast cancer in the long run should be considered. A case of a 35-year-old woman who exposed to chest irradiation as part of the treatment of Hodgkin's lymphoma at the age of 20 years is presented here and serves as a reminder of this somewhat overlooked complication. The article presents the evidence available for and against breast cancer screening in this particular patient population. PMID:26949536

  2. Blazar Duty-Cycle at Gamma-Ray Frequecies: Constraints From Extragalactic Background Radiation And Prospects for AGILE And GLAST

    SciTech Connect

    Pittori, Carlotta; Cavazzuti, Elisabetta; Colafrancesco, Sergio; Giommi, Paolo

    2011-11-29

    We take into account the constraints from the observed extragalactic {gamma}-ray background to estimate the maximum duty cycle allowed for a selected sample of WMAP Blazars, in order to be detectable by AGILE and GLAST {gamma}-ray experiments. For the nominal sensitivity values of both instruments, we identify a subset of sources which can in principle be detectable also in a steady state without over-predicting the extragalactic background. This work is based on the results of a recently derived Blazar radio LogN-LogS obtained by combining several multi-frequency surveys.

  3. Exact solutions of the Klein–Gordon equation in the Kerr–Newman background and Hawking radiation

    SciTech Connect

    Vieira, H.S.; Bezerra, V.B.; Muniz, C.R.

    2014-11-15

    This work considers the influence of the gravitational field produced by a charged and rotating black hole (Kerr–Newman spacetime) on a charged massive scalar field. We obtain exact solutions of both angular and radial parts of the Klein–Gordon equation in this spacetime, which are given in terms of the confluent Heun functions. From the radial solution, we obtain the exact wave solutions near the exterior horizon of the black hole, and discuss the Hawking radiation of charged massive scalar particles. - Highlights: • The covariant Klein–Gordon equation for a charged massive scalar field in the Kerr–Newman black hole is solved. • Both angular and radial parts are transformed to a Heun-type equation. • The resulting Hawking radiation spectrum of scalar particles has a thermal character.

  4. Radiation Therapy Planning for Early-Stage Hodgkin Lymphoma: Experience of the International Lymphoma Radiation Oncology Group

    SciTech Connect

    Maraldo, Maja V.; Dabaja, Bouthaina S.; Filippi, Andrea R.; Illidge, Tim; Tsang, Richard; Ricardi, Umberto; Petersen, Peter M.; Schut, Deborah A.; Garcia, John; Headley, Jayne; Parent, Amy; Guibord, Benoit; Ragona, Riccardo; Specht, Lena

    2015-05-01

    Purpose: Early-stage Hodgkin lymphoma (HL) is a rare disease, and the location of lymphoma varies considerably between patients. Here, we evaluate the variability of radiation therapy (RT) plans among 5 International Lymphoma Radiation Oncology Group (ILROG) centers with regard to beam arrangements, planning parameters, and estimated doses to the critical organs at risk (OARs). Methods: Ten patients with stage I-II classic HL with masses of different sizes and locations were selected. On the basis of the clinical information, 5 ILROG centers were asked to create RT plans to a prescribed dose of 30.6 Gy. A postchemotherapy computed tomography scan with precontoured clinical target volume (CTV) and OARs was provided for each patient. The treatment technique and planning methods were chosen according to each center's best practice in 2013. Results: Seven patients had mediastinal disease, 2 had axillary disease, and 1 had disease in the neck only. The median age at diagnosis was 34 years (range, 21-74 years), and 5 patients were male. Of the resulting 50 treatment plans, 15 were planned with volumetric modulated arc therapy (1-4 arcs), 16 with intensity modulated RT (3-9 fields), and 19 with 3-dimensional conformal RT (2-4 fields). The variations in CTV-to-planning target volume margins (5-15 mm), maximum tolerated dose (31.4-40 Gy), and plan conformity (conformity index 0-3.6) were significant. However, estimated doses to OARs were comparable between centers for each patient. Conclusions: RT planning for HL is challenging because of the heterogeneity in size and location of disease and, additionally, to the variation in choice of treatment techniques and field arrangements. Adopting ILROG guidelines and implementing universal dose objectives could further standardize treatment techniques and contribute to lowering the dose to the surrounding OARs.

  5. A susceptible-infected model of early detection of respiratory infection outbreaks on a background of influenza.

    PubMed

    Mohtashemi, Mojdeh; Szolovits, Peter; Dunyak, James; Mandl, Kenneth D

    2006-08-21

    The threat of biological warfare and the emergence of new infectious agents spreading at a global scale have highlighted the need for major enhancements to the public health infrastructure. Early detection of epidemics of infectious diseases requires both real-time data and real-time interpretation of data. Despite moderate advancements in data acquisition, the state of the practice for real-time analysis of data remains inadequate. We present a nonlinear mathematical framework for modeling the transient dynamics of influenza, applied to historical data sets of patients with influenza-like illness. We estimate the vital time-varying epidemiological parameters of infections from historical data, representing normal epidemiological trends. We then introduce simulated outbreaks of different shapes and magnitudes into the historical data, and estimate the parameters representing the infection rates of anomalous deviations from normal trends. Finally, a dynamic threshold-based detection algorithm is devised to assess the timeliness and sensitivity of detecting the irregularities in the data, under a fixed low false-positive rate. We find that the detection algorithm can identify such designated abnormalities in the data with high sensitivity with specificity held at 97%, but more importantly, early during an outbreak. The proposed methodology can be applied to a broad range of influenza-like infectious diseases, whether naturally occurring or a result of bioterrorism, and thus can be an integral component of a real-time surveillance system. PMID:16556450

  6. Anti-inflammatory and Anti-apoptotic Effect of Valproic Acid and Doxycycline Independent from MMP Inhibition in Early Radiation Damage

    PubMed Central

    Hoşgörler, Ferda; Keleş, Didem; Tanrıverdi-Akhisaroğlu, Serpil; İnanç, Şeniz; Akhisaroğlu, Mustafa; Cankurt, Ülker; Aydoğdu, Zekiye; Uçar, Ahmet Deniz; Çetinayak, Oğuz; Oktay, Gülgün; Arda, Sevil Gönenç

    2016-01-01

    Background: Matrix metalloproteinase (MMP) inhibitors decrease inflammation in normal tissues and suppress cancer progress in normal tissues. Valproic acid (VA) and doxycycline (DX) are MMP inhibitors that have radio-protective effects. Their ability to inhibit MMPs in irradiated tissue is unknown and the role of MMPs in radio-protective effects has not been tested to date. Aims: The purpose of this study was to examine whether administration of VA and DX to rats before irradiation affects tissue inflammation and apoptosis in the early phase of radiation, and whether the effect of these drugs is mediated by MMP inhibition. Study Design: Animal experimentation. Methods: Twenty-six Wistar rats were randomized into four groups: control (CTRL), radiation (RT), VA plus radiation (VA+RT), and DX plus radiation (DX+RT). Three study groups were exposed to a single dose of abdominal 10 Gy gamma radiation; the CTRL group received no radiation. Single doses of VA 300 mg/kg and DX 100 mg/kg were administered to each rat before radiation and all rats were sacrificed 8 hours after irradiation, at which point small intestine tissue samples were taken for analyses. Levels of inflammatory cytokines (TNF-α, IL-1β, and IL-6) and matrix metal-loproteinases (MMP-2 and MMP 9) were measured by ELISA, MMP activities were measured by gelatin and casein zymography and apoptosis was assessed by terminal deoxynucleotidyl transferase dUTP nick end labeling assay. Results: VA decreased the levels of TNF-α and IL-1β proteins insignificantly and decreased apoptosis significantly in the irradiated tissue, but did not inhibit MMPs. In contrast, VA protected the basal MMP activities, which decreased in response to irradiation. No effect of DX was observed on the levels of inflammatory cytokines or activities of MMPs in the early phases of radiation apoptosis. Conclusion: Our findings indicated that VA protects against inflammation and apoptosis, and DX exhibits anti-apoptotic effects in early

  7. Role of radiation in the management of early vocal cord carcinoma

    SciTech Connect

    Mittal, B.; Rao, D.V.; Marks, J.E.; Perez, C.A.

    1983-07-01

    From 1952 to 1978, 177 patients with epidermoid carcinoma confined to the true vocal cords with normal mobility (T1NO) were treated with radiation alone. Five- and 10-year adjusted actuarial survival rates for all patients were 97 and 95%, respectively. The tumor recurred in the larynx and/or neck in 16% of patients with T/sub 1a/ (one cord involved) and 23% of the patients with T/sub 1b/ (both vocal cords involved) disease. Radiation failures were surgically salvaged in 89% of patients with T/sub 1a/ disease without anterior commissure involvement, in 60% of those with T/sub 1a/ disease with anterior commissure involvement and in 57% of those with T/sub 1b/ disease. Tumor was ultimately controlled in 97% of the patients with T/sub 1a/ and 90% of the patients with T/sub 1b/ disease. Voice was preserved in 93% of the patients with T/sub 1a/ disease and 77% of patients with T/sub 1b/ disease. Of 121 patients evaluated for voice quality 77% had good and 22% had fair voice, while only one patient had poor quality of voice. Patients with fair or poor quality voice usually had had salvage hemilaryngectomy. We recommend radiation for all patients with early vocal cord carcinoma.

  8. Applications in Bioastronautics and Bioinformatics: Early Radiation Cataracts Detected by Noninvasive, Quantitative, and Remote Means

    NASA Technical Reports Server (NTRS)

    Ansari, Rafat R.; King, James F.; Giblin, Frank J.

    2000-01-01

    Human exploration of Mars is a key goal in NASA's exploration planning in the next 20 years. Maintaining crew health and good vision is certainly an important aspect of achieving a successful mission. Continuous radiation exposure is a risk factor for radiation-induced cataracts in astronauts because radiation exposure in space travel has the potential of accelerating the aging process (ref. 1). A patented compact device (ref. 2) based on the technique of dynamic light scattering (DLS) was designed for monitoring an astronaut's ocular health during long-duration space travel. This capability of early diagnosis, unmatched by any other clinical technique in use today, may enable prompt initiation of preventive/curative therapy. An Internet web-based system integrating photon correlation data and controlling the hardware to monitor cataract development in vivo at a remote site in real time (teleophthalmology) is currently being developed. The new technology detects cataracts very early (at the molecular level). Cataract studies onboard the International Space Station will be helpful in quantifying any adverse effect of radiation to ocular health. The normal lens in a human eye, situated behind the cornea, is a transparent tissue. It contains 35 wt % protein and 65 wt % water. Aging, disease (e.g., diabetes), smoking, dehydration, malnutrition, and exposure to ultraviolet light and ionizing radiation can cause agglomeration of the lens proteins. Protein aggregation can take place anywhere in the lens, causing lens opacity. The aggregation and opacification could produce nuclear (central portion of the lens) or cortical (peripheral) cataracts. Nuclear and posterior subcapsular (the membrane's capsule surrounds the whole lens) cataracts, being on the visual optical axis of the eye, cause visual impairment that can finally lead to blindness. The lens proteins, in their native state, are small in size. As a cataract develops, this size grows from a few nanometers

  9. Inhalation exposures due to radon and thoron ((222)Rn and (220)Rn): Do they differ in high and normal background radiation areas in India?

    PubMed

    Mishra, Rosaline; Sapra, B K; Prajith, R; Rout, R P; Jalaluddin, S; Mayya, Y S

    2015-09-01

    In India, High Background Radiation Areas (HBRAs) due to enhanced levels of naturally occurring radionuclides in soil (thorium and, to a lesser extent, uranium), are located along some parts of the coastal tracts viz. the coastal belt of Kerala, Tamilnadu and Odisha. It is conjectured that these deposits will result in higher emissions of radon isotopes ((222)Rn and (220)Rn) and their daughter products as compared to Normal Background Radiation Areas (NBRAs). While the annual external dose rates contributed by gamma radiations in these areas are about 5-10 times higher, the extent of increase in the inhalation dose rates attributable to (222)Rn and (220)Rn and their decay products is not well quantified. Towards this, systematic indoor surveys were conducted wherein simultaneous measurements of time integrated (222)Rn and (220)Rn gas and their decay product concentrations was carried out in around 800 houses in the HBRAs of Kerala and Odisha to estimate the inhalation doses. All gas measurements were carried out using pin-hole cup dosimeters while the progeny measurements were with samplers and systems based on the Direct radon/thoron Progeny sensors (DRPS/DTPS). To corroborate these passive measurements of decay products concentrations, active sampling was also carried out in a few houses. The results of the surveys provide a strong evidence to conclude that the inhalation doses due to (222)Rn and (220)Rn gas and their decay products in these HBRAs are in the same range as observed in the NBRAs in India. PMID:26065929

  10. FROM THE HISTORY OF PHYSICS: How Gamow calculated the temperature of the background radiation or a few words about the fine art of theoretical physics

    NASA Astrophysics Data System (ADS)

    Chernin, Artur D.

    1994-08-01

    In a paper published in 1953, i.e., more than a decade before the observational discovery of the cosmic microwave background radiation, George Gamow predicted theoretically the temperature of this radiation. He estimated it to be 7 K, which is very close to the subsequently measured value of about 3 K. Gamow found the present temperature of the background radiation on the basis of general formulas of cosmological dynamics. This prediction was in no way related to primordial nucleosynthesis.This circumstance has and is still causing misunderstanding in those cases in which the authors have raised doubts about Gamow's results, although an actual error has never been demonstrated. A detailed analysis makes it possible to understand how Gamow's calculation is possible. The problem lies in the fact that Gamow makes a certain additional implicit assumption which allows him to dispense with information on nucleosynthesis. This assumption is discussed in the context of the state of cosmology in the period from the fifties to the seventies, and of the current status of this branch of science.

  11. Adoption of Intensity Modulated Radiation Therapy For Early-Stage Breast Cancer From 2004 Through 2011

    SciTech Connect

    Wang, Elyn H.; Mougalian, Sarah S.; Soulos, Pamela R.; Smith, Benjamin D.; Haffty, Bruce G.; Gross, Cary P.; Yu, James B.

    2015-02-01

    Purpose: Intensity modulated radiation therapy (IMRT) is a newer method of radiation therapy (RT) that has been increasingly adopted as an adjuvant treatment after breast-conserving surgery (BCS). IMRT may result in improved cosmesis compared to standard RT, although at greater expense. To investigate the adoption of IMRT, we examined trends and factors associated with IMRT in women under the age of 65 with early stage breast cancer. Methods and Materials: We performed a retrospective study of early stage breast cancer patients treated with BCS followed by whole-breast irradiation (WBI) who were ≤65 years old in the National Cancer Data Base from 2004 to 2011. We used logistic regression to identify factors associated with receipt of IMRT (vs standard RT). Results: We identified 11,089 women with early breast cancer (9.6%) who were treated with IMRT and 104,448 (90.4%) who were treated with standard RT, after BCS. The proportion of WBI patients receiving IMRT increased yearly from 2004 to 2009, with 5.3% of WBI patients receiving IMRT in 2004 and 11.6% receiving IMRT in 2009. Further use of IMRT declined afterward, with the proportion remaining steady at 11.0% and 10.7% in 2010 and 2011, respectively. Patients treated in nonacademic community centers were more likely to receive IMRT (odds ratio [OR], 1.36; 95% confidence interval [CI], 1.30-1.43 for nonacademic vs academic center). Compared to privately insured patients, the uninsured patients (OR, 0.81; 95% CI, 0.70-0.95) and those with Medicaid insurance (OR, 0.87; 95% CI, 0.79-0.95) were less likely to receive IMRT. Conclusions: The use of IMRT rose from 2004 to 2009 and then stabilized. Important nonclinical factors associated with IMRT use included facility type and insurance status.

  12. [Observation study on aerosol optical properties and radiative forcing using the ground-based and satellite remote sensing at background station during the regional pollution episodes].

    PubMed

    Zhang, Xiao-Ling; Xia, Xiang-Ao; Che, Hui-Zheng; Tang, Jie; Tang, Yi-Xi; Meng, Wei; Dong, Fan

    2014-07-01

    The significant effect of anthropogenic pollutants transportation on the physical and optical properties of regional background atmospheric aerosol was studied by using ground-based and satellite remote sensing data obtained at the atmospheric background station (Shangdianzi, Beijing) of North China during October 1 to 15 in 2011. The aerosol mass concentration and reactive gases concentration increased obviously during periods of October 4-5, October 7-9, and October 11-12. Comparing with the background period of October 1-3, volume concentration increased by a factor of 3-6 for reactive gases such as NO(x), and CO, and a factor of 10-20 for SO2. Mass concentration of PM2.5 was about 200 microg x m(-3) on October 9. During haze period, the AOD at 500 nm varied between 0.60 to 1.00. The single scattering albedo (SSA) was lower than 0.88. And the black carbon concentration increased 4-8 times, which suggested the aerosol absorption was very strong during this pollution episode. The absorption of aerosol particles could cause 100-400 W x m(-2) increase of atmospheric radiation. The surface radiation decreased by about 100-300 W x m(-2) due to the aerosol scattering and absorption. This could cause higher stability of atmosphere, which will significantly affect the cloud and precipitation, and thus the regional weather and climate.

  13. [Changes in the chromatin structure of lymphoid cells under the influence of low-intensity extremely high-frequency electromagnetic radiation against the background of inflammatory process].

    PubMed

    Gapeev, A B; Romanova, N A; Chemeris, N K

    2011-01-01

    Using the alkaline single cell gel electrophoresis technique (comet assay), changes in chromatin structure of peripheral blood leukocytes and peritoneal neutrophils have been studied in mice exposed to low-intensity extremely high-frequency electromagnetic radiation (42.2 GHz, 0.1 mW/cm2, 20 min at 1 h after induction of inflammation) against the background of the systemic inflammatory process. It was revealed that the exposure of mice with the developing inflammation leads to a pronounced decrease in the level of DNA damage to peripheral blood leukocytes and peritoneal neutrophils. It is supposed that the changes in the chromatin structure of lymphoid cells have a genoprotective character in the inflammatory process and can underlie the mechanisms of realization of antiinflammatory effects of the electromagnetic radiation.

  14. Products from cosmic-ray interactions in extraterrestrial matter: What they tell us about radiation backgrounds in space

    SciTech Connect

    Reedy, R.C.

    1987-01-01

    The nuclides and the heavy-nuclei ''tracks'' made by the interactions of solar and galactic cosmic-ray particles with meteorites, lunar samples, and the Earth have been extensively studied, simulated, and modelled. Most research involves the use of these cosmogenic products to study the history of the ''targets'' or of the cosmic rays. However, much work has also been done in understanding these interactions and in predicting their rates as a function of the target's size and shape and of the location inside the target. These studies apply to any object exposed to cosmic rays. The fluxes as a function of depth for cosmic-ray primary and secondary particles vary greatly with particle energy and type. The variations of the fluxes of these cosmic rays in the past have been studied. Energetic solar particles are unpredictable and are the greatest potential radiation hazard in space. 11 refs., 1 fig.

  15. Radiocarbon dating of archaeological samples (sambaqui) using CO(2) absorption and liquid scintillation spectrometry of low background radiation.

    PubMed

    Mendonça, Maria Lúcia T G; Godoy, José M; da Cruz, Rosana P; Perez, Rhoneds A R

    2006-01-01

    Sambaqui means, in the Tupi language, a hill of shells. The sambaquis are archaeological sites with remains of pre-historical Brazilian occupation. Since the sambaqui sites in the Rio de Janeiro state region are older than 10,000 years, the applicability of CO(2) absorption on Carbo-sorb and (14)C determination by counting on a low background liquid scintillation counter was tested. In the present work, sambaqui shells were treated with H(3)PO(4) in a closed vessel in order to generate CO(2). The produced CO(2) was absorbed on Carbo-sorb. On saturation about 0.6g of carbon, as CO(2), was mixed with commercial liquid scintillation cocktail (Permafluor), and the (14)C activity determined by counting on a low background counter, Packard Tricarb 3170 TR/SL, for a period of 1000 mins to enable detection of a radiocarbon age of 22,400 BP. But only samples with ages up to 3500 BP were submitted to the method because the samples had been collected in the municipality of Guapimirim, in archaeological sambaqui-type sites belonging to this age range. The same samples were sent to the (14)C Laboratory of the Centro de Energia Nuclear na Agricultura (CENA/USP) where similar results were obtained.

  16. Limits on the radiative decay of sterile neutrino dark matter from the unresolved cosmic and soft x-ray backgrounds

    NASA Astrophysics Data System (ADS)

    Abazajian, Kevork N.; Markevitch, Maxim; Koushiappas, Savvas M.; Hickox, Ryan C.

    2007-03-01

    We present upper limits on line emission in the Cosmic X-ray background (CXB) that would be produced by decay of sterile neutrino dark matter. We employ the spectra of the unresolved component of the CXB in the Chandra Deep Fields North and South obtained with the Chandra CCD detector in the E=0.8 9keV band. The expected decay flux comes from the dark matter on the lines of sight through the Milky Way galactic halo. Our constraints on the sterile neutrino decay rate are sensitive to the modeling of the Milky Way halo. The highest halo mass estimates provide a limit on the sterile neutrino mass of ms<2.9keV in the Dodelson-Widrow production model, while the lowest halo mass estimates provide the conservative limit of ms<5.7keV (2σ). We also discuss constraints from a short observation of the softer (E<1keV) X-ray background with a rocket-borne calorimeter by McCammon and collaborators.

  17. Coronary Calcium Scanning in Patients after Adjuvant Radiation for Early Breast Cancer and Ductal Carcinoma In situ

    PubMed Central

    Chang, Monique; Suh, Jason; Kirtani, Vatsala; Dobrescu, Andrei; Haas, Jonathan; Zeldis, Steven; Shayani, Steven; Hindenburg, Alexander A.

    2013-01-01

    Background and Objective: Radiation therapy (RT) is part of standard adjuvant treatment for breast cancer. Earlier studies demonstrated increased cardiac morbidity and mortality from this. Coronary Calcium scanning utilizing Multidetector Computed Tomography (MDCT) can detect early atherosclerosis in coronary arteries by identifying the amount of calcifications. In our study we employed these tools to detect occult atherosclerosis at least 5 years following breast RT. Methods: We evaluated 20 asymptomatic patients, <60 years old, treated with RT at least 5 years prior to enrollment. Nine received RT to the left and 11 to the right chest wall. The median interval between RT and calcium scan was 8 years. All patients were treated with external beam RT using tangential technique. All patients underwent MDCT to compute volumetric and Agatston calcium scores of the coronary arteries and the aorta. Results: Eleven patients had RT to the right chest wall, and eight had a calcium score of 0, while two had minimally elevated scores and one patient had a significantly elevated score. Meanwhile nine patients had RT to the left chest wall, and seven had a calcium score of 0. None had significantly elevated scores. In the aorta, 11 of 20 patients had a score of 0, while 8 of 20 had minimally elevated scores. Conclusion: In contrast to studies demonstrating increased cardiovascular morbidity, our pilot study did not detect significant occult atherosclerosis using MDCT of the coronaries and aorta of patients assessed five or more years following radiation for treatment of breast cancer. PMID:24093087

  18. The temperature of the cosmic microwave background radiation at 3.8 GHz - Results of a measurement from the South Pole site

    NASA Technical Reports Server (NTRS)

    De Amici, Giovanni; Limon, Michele; Smoot, George F.; Bersanelli, Marco; Kogut, AL; Levin, Steve

    1991-01-01

    As part of an international collaboration to measure the low-frequency spectrum of the cosmic microwave background (CMB) radiation, its temperature was measured at a frequency of 3.8 GHz, during the austral spring of 1989, obtaining a brightness temperature, T(CMB), of 2.64 +/-0.07 K (68 percent confidence level). The new result is in agreement with previous measurements at the same frequency obtained in 1986-88 from a very different site and has comparable error bars. Combining measurements from all years, T(CMB) = 2.64 +/-0.06 K is obtained.

  19. Application of radiation physics to improve dosimetry in early breast cancer radiotherapy

    SciTech Connect

    Donovan, Ellen Mary

    2005-07-15

    Radiotherapy for early breast cancer has been shown to be a highly effective treatment in a number of long term studies. The radiation dose uniformity of the current standard treatments is often poor, however, with dose variations across the breast much higher than those recommended in international guidelines. This work aimed to explore methods for improving this aspect of the radiation dosimetry of early breast cancer radiotherapy. An experimental method was validated by applying it to computed tomography data from 14 patients with a variety of breast shapes and sizes. The volume of the breast receiving the desired dose levels increased by a mean of 6.9% (range -0.8% to 15.9%) and this benefit was shown to increase with breast volume. The quality of reference images in the verification of treatments was improved by introducing differential filtering to the imaging beams on a radiotherapy simulator. The positive results from the first two studies were applied in a clinical trial (which used the experimental technique). The unique set of data from the trial was analyzed and confirmation of dosimetric improvement, and the increased benefit, for larger breasted women were found. In addition, an analysis of the position of high doses showed these occurred in the upper or lower third of the breast and affected 46% and 30% of patients, respectively, with standard treatment but only 1% of patients with the improved method. Other published methods for improving breast dosimetry were explored by building a simple physical model and carrying out a comparative planning study. The physical model was shown to be effective in predicting the dosimetric consequences of each method. The planning study showed that there was little difference between the methods generally but dosimetric improvement could be increased for larger breast volumes by an appropriate choice of technique. A final study explored how breathing control could be used to reduce cardiac doses in patients with

  20. The amplitude and spectral index of the large angular scale anisotropy in the cosmic microwave background radiation

    NASA Technical Reports Server (NTRS)

    Ganga, Ken; Page, Lyman; Cheng, Edward; Meyer, Stephan

    1994-01-01

    In many cosmological models, the large angular scale anisotropy in the cosmic microwave background is parameterized by a spectral index, n, and a quadrupolar amplitude, Q. For a Harrison-Peebles-Zel'dovich spectrum, n = 1. Using data from the Far Infrared Survey (FIRS) and a new statistical measure, a contour plot of the likelihood for cosmological models for which -1 less than n less than 3 and 0 equal to or less than Q equal to or less than 50 micro K is obtained. Depending upon the details of the analysis, the maximum likelihood occurs at n between 0.8 and 1.4 and Q between 18 and 21 micro K. Regardless of Q, the likelihood is always less than half its maximum for n less than -0.4 and for n greater than 2.2, as it is for Q less than 8 micro K and Q greater than 44 micro K.

  1. Human radiation studies: Remembering the early years. Oral history of Julie Langham Grilly, February 3, 1995

    SciTech Connect

    1995-09-01

    Julie Langham Grilly was interviewed by representatives of the US DOE Office of Human Radiation Experiments (OHRE) being the widow of Dr. Wright Langham, an investigator of principal interest of the committee. Her extensive experience with research at LANL was also of interest to the committee. Following a brief biographical sketch, Ms. Grilly relates her early postwar experience and her knowledge of Wright Langham`s involvement in animal research at Los Alamos, radiolanthanum tests on monkeys, Eniwetok tissue examinations, research on tritium uptake in humans, plutonium injections, tritium injections, EDTA, and etc. In addition to illuminating her former husband as a researcher and as an individual, she also relates her remembrances of Louis Hempelman, Enrico Fermi, Oppenheimer, Edward Teller, and many others.

  2. Photonic Integrated Circuit (PIC) Device Structures: Background, Fabrication Ecosystem, Relevance to Space Systems Applications, and Discussion of Related Radiation Effects

    NASA Technical Reports Server (NTRS)

    Alt, Shannon

    2016-01-01

    Electronic integrated circuits are considered one of the most significant technological advances of the 20th century, with demonstrated impact in their ability to incorporate successively higher numbers transistors and construct electronic devices onto a single CMOS chip. Photonic integrated circuits (PICs) exist as the optical analog to integrated circuits; however, in place of transistors, PICs consist of numerous scaled optical components, including such "building-block" structures as waveguides, MMIs, lasers, and optical ring resonators. The ability to construct electronic and photonic components on a single microsystems platform offers transformative potential for the development of technologies in fields including communications, biomedical device development, autonomous navigation, and chemical and atmospheric sensing. Developing on-chip systems that provide new avenues for integration and replacement of bulk optical and electro-optic components also reduces size, weight, power and cost (SWaP-C) limitations, which are important in the selection of instrumentation for specific flight projects. The number of applications currently emerging for complex photonics systems-particularly in data communications-warrants additional investigations when considering reliability for space systems development. This Body of Knowledge document seeks to provide an overview of existing integrated photonics architectures; the current state of design, development, and fabrication ecosystems in the United States and Europe; and potential space applications, with emphasis given to associated radiation effects and reliability.

  3. Early-response biomarkers for assessment of radiation exposure in a mouse total-body irradiation model.

    PubMed

    Ossetrova, Natalia I; Condliffe, Donald P; Ney, Patrick H; Krasnopolsky, Katya; Hieber, Kevin P; Rahman, Arifur; Sandgren, David J

    2014-06-01

    Nuclear accidents or terrorist attacks could expose large numbers of people to ionizing radiation. Early biomarkers of radiation injury will be critical for triage, treatment, and follow-up of such individuals. The authors evaluated the utility of multiple blood biomarkers for early-response assessment of radiation exposure using a murine (CD2F1, males) total-body irradiation (TBI) model exposed to ⁶⁰Co γ rays (0.6 Gy min⁻¹) over a broad dose range (0-14 Gy) and timepoints (4 h-5 d). Results demonstrate: 1) dose-dependent changes in hematopoietic cytokines: Flt-3 ligand (Flt3L), interleukin 6 (IL-6), granulocyte colony stimulating factor (G-CSF), thrombopoietin (TPO), erythropoietin (EPO), and acute phase protein serum amyloid A (SAA); 2) dose-dependent changes in blood cell counts: lymphocytes, neutrophils, platelets, and ratio of neutrophils to lymphocytes; 3) protein results coupled with peripheral blood cell counts established very successful separation of groups irradiated to different doses; and 4) enhanced separation of dose was observed as the number of biomarkers increased. Results show that the dynamic changes in the levels of SAA, IL-6, G-CSF, and Flt3L reflect the time course and severity of acute radiation syndrome (ARS) and may function as prognostic indicators of ARS outcome. These results also demonstrate proof-in-concept that plasma proteins show promise as a complimentary approach to conventional biodosimetry for early assessment of radiation exposures and, coupled with peripheral blood cell counts, provide early diagnostic information to manage radiation casualty incidents effectively, closing a gap in capabilities to rapidly and effectively assess radiation exposure early, especially needed in case of a mass-casualty radiological incident.

  4. Unraveling low-level gamma radiation--responsive changes in expression of early and late genes in leaves of rice seedlings at Iitate Village, Fukushima.

    PubMed

    Hayashi, Gohei; Shibato, Junko; Imanaka, Tetsuji; Cho, Kyoungwon; Kubo, Akihiro; Kikuchi, Shoshi; Satoh, Kouji; Kimura, Shinzo; Ozawa, Shoji; Fukutani, Satoshi; Endo, Satoru; Ichikawa, Katsuki; Agrawal, Ganesh Kumar; Shioda, Seiji; Fukumoto, Manabu; Rakwal, Randeep

    2014-01-01

    In the summer of 2012, 1 year after the nuclear accident in March 2011 at the Fukushima Daiichi nuclear power plant, we examined the effects of gamma radiation on rice at a highly contaminated field of Iitate village in Fukushima, Japan. We investigated the morphological and molecular changes on healthy rice seedlings exposed to continuous low-dose gamma radiation up to 4 µSv h(-1), about 80 times higher than natural background level. After exposure to gamma rays, expression profiles of selected genes involved in DNA replication/repair, oxidative stress, photosynthesis, and defense/stress functions were examined by RT-PCR, which revealed their differential expression in leaves in a time-dependent manner over 3 days (6, 12, 24, 48, and 72 h). For example, OsPCNA mRNA rapidly increased at 6, 12, and 24 h, suggesting that rice cells responded to radiation stress by activating a gene involved in DNA repair mechanisms. At 72 h, genes related to the phenylpropanoid pathway (OsPAL2) and cell death (OsPR1oa) were strongly induced, indicating activation of defense/stress responses. We next profiled the transcriptome using a customized rice whole-genome 4×44K DNA microarray at early (6h) and late (72 h) time periods. Low-level gamma radiation differentially regulated rice leaf gene expression (induced 4481 and suppressed 3740 at 6 h and induced 2291 and suppressed 1474 genes at 72 h) by at least 2-fold. Using the highly upregulated and downregulated gene list, MapMan bioinformatics tool generated diagrams of early and late pathways operating in cells responding to gamma ray exposure. An inventory of a large number of gamma radiation-responsive genes provides new information on novel regulatory processes in rice.

  5. Unraveling low-level gamma radiation--responsive changes in expression of early and late genes in leaves of rice seedlings at Iitate Village, Fukushima.

    PubMed

    Hayashi, Gohei; Shibato, Junko; Imanaka, Tetsuji; Cho, Kyoungwon; Kubo, Akihiro; Kikuchi, Shoshi; Satoh, Kouji; Kimura, Shinzo; Ozawa, Shoji; Fukutani, Satoshi; Endo, Satoru; Ichikawa, Katsuki; Agrawal, Ganesh Kumar; Shioda, Seiji; Fukumoto, Manabu; Rakwal, Randeep

    2014-01-01

    In the summer of 2012, 1 year after the nuclear accident in March 2011 at the Fukushima Daiichi nuclear power plant, we examined the effects of gamma radiation on rice at a highly contaminated field of Iitate village in Fukushima, Japan. We investigated the morphological and molecular changes on healthy rice seedlings exposed to continuous low-dose gamma radiation up to 4 µSv h(-1), about 80 times higher than natural background level. After exposure to gamma rays, expression profiles of selected genes involved in DNA replication/repair, oxidative stress, photosynthesis, and defense/stress functions were examined by RT-PCR, which revealed their differential expression in leaves in a time-dependent manner over 3 days (6, 12, 24, 48, and 72 h). For example, OsPCNA mRNA rapidly increased at 6, 12, and 24 h, suggesting that rice cells responded to radiation stress by activating a gene involved in DNA repair mechanisms. At 72 h, genes related to the phenylpropanoid pathway (OsPAL2) and cell death (OsPR1oa) were strongly induced, indicating activation of defense/stress responses. We next profiled the transcriptome using a customized rice whole-genome 4×44K DNA microarray at early (6h) and late (72 h) time periods. Low-level gamma radiation differentially regulated rice leaf gene expression (induced 4481 and suppressed 3740 at 6 h and induced 2291 and suppressed 1474 genes at 72 h) by at least 2-fold. Using the highly upregulated and downregulated gene list, MapMan bioinformatics tool generated diagrams of early and late pathways operating in cells responding to gamma ray exposure. An inventory of a large number of gamma radiation-responsive genes provides new information on novel regulatory processes in rice. PMID:25124817

  6. Hematopoietic cell crisis: An early stage of evolving myeloid leukemia following radiation exposure

    SciTech Connect

    Seed, T.M.

    1990-01-01

    Under select radiological conditions, chronic radiation exposure elicits a high incidence of myeloproliferative disease, principally myeloid leukemia (ML), in beagles. Previously we demonstrated that for full ML expression, a four-stage preclinical sequence is required, namely (1) suppression, (2) recovery, (3) accommodation, and (4) preleukemic transition. Within this pathological sequence, a critical early event has been identified as the acquisition of radioresistance by hematopoietic progenitors that serves to mediate a newfound regenerative hematopoietic capacity. As such, this event sets the stage'' for preleukemic progression by initiating progression from preclinical phase 1 to 2. Due to the nature of target cell suppression, the induction of crisis, and the outgrowth of progenitors with altered phenotypes, this preleukemic event resembles the immortalization'' step of the in vitro transformation sequence following induction with either physical and chemical carcinogens. The radiological, temporal, and biological dictates governing this event have been extensively evaluated and will be discussed in light of their role in the induction and progression of chronic radiation leukemia. 35 refs., 2 tabs.

  7. Role of light and heavy minerals on natural radioactivity level of high background radiation area, Kerala, India.

    PubMed

    Ramasamy, V; Sundarrajan, M; Suresh, G; Paramasivam, K; Meenakshisundaram, V

    2014-02-01

    Natural radionuclides ((238)U, (232)Th and (40)K) concentrations and eight different radiological parameters have been analyzed for the beach sediments of Kerala with an aim of evaluating the radiation hazards. Activity concentrations ((238)U and (232)Th) and all the radiological parameters in most of the sites have higher values than recommended values. The Kerala beach sediments pose significant radiological threat to the people living in the area and tourists going to the beaches for recreation or to the sailors and fishermen involved in their activities in the study area. In order to know the light mineral characterization of the present sediments, mineralogical analysis has been carried out using Fourier transform infrared (FTIR) spectroscopic technique. The eight different minerals are identified and they are characterized. Among the various observed minerals, the minerals such as quartz, microcline feldspar, kaolinite and calcite are major minerals. The relative distribution of major minerals is determined by calculating extinction co-efficient and the values show that the amount of quartz is higher than calcite and much higher than microcline feldspar. Crystallinity index is calculated to know the crystalline nature of quartz present in the sediments. Heavy mineral separation analysis has been carried out to know the total heavy mineral (THM) percentage. This analysis revealed the presence of nine heavy minerals. The minerals such as monazite, zircon, magnetite and illmenite are predominant. Due to the rapid and extreme changes occur in highly dynamic environments of sandy beaches, quantities of major light and heavy minerals are widely varied from site to site. Granulometric analysis shows that the sand is major content. Multivariate statistical (Pearson correlation, cluster and factor) analysis has been carried out to know the effect of mineralogy on radionuclide concentrations. The present study concluded that heavy minerals induce the (238)U and (232)Th

  8. Theoretical analysis of the background intensity distribution in X-ray Birefringence Imaging using synchrotron bending-magnet radiation

    SciTech Connect

    Sutter, John P. Dolbnya, Igor P.; Collins, Stephen P.; Harris, Kenneth D. M.; Edwards-Gau, Gregory R.; Palmer, Benjamin A.

    2015-04-28

    In the recently developed technique of X-ray Birefringence Imaging, molecular orientational order in anisotropic materials is studied by exploiting the birefringence of linearly polarized X-rays with energy close to an absorption edge of an element in the material. In the experimental setup, a vertically deflecting high-resolution double-crystal monochromator is used upstream from the sample to select the appropriate photon energy, and a horizontally deflecting X-ray polarization analyzer, consisting of a perfect single crystal with a Bragg reflection at Bragg angle of approximately 45°, is placed downstream from the sample to measure the resulting rotation of the X-ray polarization. However, if the experiment is performed on a synchrotron bending-magnet beamline, then the elliptical polarization of the X-rays out of the electron orbit plane affects the shape of the output beam. Also, because the monochromator introduces a correlation between vertical position and photon energy to the X-ray beam, the polarization analyzer does not select the entire beam, but instead selects a diagonal stripe, the slope of which depends on the Bragg angles of the monochromator and the polarization analyzer. In the present work, the final background intensity distribution is calculated analytically because the phase space sampling methods normally used in ray traces are too inefficient for this setup. X-ray Birefringence Imaging data measured at the Diamond Light Source beamline B16 agree well with the theory developed here.

  9. The Cosmic Background Explorer

    NASA Technical Reports Server (NTRS)

    Gulkis, Samuel; Lubin, Philip M.; Meyer, Stephan S.; Silverberg, Robert F.

    1990-01-01

    The Cosmic Background Explorer (CBE), NASA's cosmological satellite which will observe a radiative relic of the big bang, is discussed. The major questions connected to the big bang theory which may be clarified using the CBE are reviewed. The satellite instruments and experiments are described, including the Differential Microwave Radiometer, which measures the difference between microwave radiation emitted from two points on the sky, the Far-Infrared Absolute Spectrophotometer, which compares the spectrum of radiation from the sky at wavelengths from 100 microns to one cm with that from an internal blackbody, and the Diffuse Infrared Background Experiment, which searches for the radiation from the earliest generation of stars.

  10. Peripheral blood lymphocyte micronucleus frequencies in men from areas of Kerala, India, with high vs normal levels of natural background ionizing radiation.

    PubMed

    Karuppasamy, C V; Ramachandran, E N; Kumar, V Anil; Kumar, P R Vivek; Koya, P K M; Jaikrishan, G; Das, Birajalaxmi

    2016-04-01

    We have measured the frequencies of micronuclei (MN) in adult male individuals living in areas of the Kerala coast, southwest India, with either high (HLNRA, >1.5mGy/year) or normal levels of natural ionizing radiation (NLNRA, ≤1.5mGy/year). Blood samples were obtained from 141 individuals, 94 from HLNRA and 47 from NLNRA, aged 18-72, and were subjected to the cytokinesis-block micronucleus (CBMN) assay. An average of 1835 binucleated (BN) cells per individual were scored. The overall frequency of MN (mean±SD) was 11.7±6.7 per 1000 BN cells. The frequencies of MN in the HLNRA (11.7±6.6) and NLNRA (11.6±6.7) were not statistically significantly different (P=0.59). However, a statistically significant (P<0.001) age-dependent increase in MN frequency was observed among individuals from both HLNRA and NLNRA. No natural background radiation dose-dependent increase in MN frequency was seen. MN frequency was not influenced by tobacco smoking or chewing but it was increased among individuals consuming alcohol. Chronic low-dose radiation in the Kerala coast did not have a significant effect on MN frequency among adult men. PMID:27085474

  11. RADIATION MAGNETOHYDRODYNAMIC SIMULATIONS OF PROTOSTELLAR COLLAPSE: NONIDEAL MAGNETOHYDRODYNAMIC EFFECTS AND EARLY FORMATION OF CIRCUMSTELLAR DISKS

    SciTech Connect

    Tomida, Kengo; Okuzumi, Satoshi; Machida, Masahiro N. E-mail: okuzumi@geo.titech.ac.jp

    2015-03-10

    The transport of angular momentum by magnetic fields is a crucial physical process in the formation and evolution of stars and disks. Because the ionization degree in star-forming clouds is extremely low, nonideal magnetohydrodynamic (MHD) effects such as ambipolar diffusion and ohmic dissipation work strongly during protostellar collapse. These effects have significant impacts in the early phase of star formation as they redistribute magnetic flux and suppress angular momentum transport by magnetic fields. We perform three-dimensional nested-grid radiation magnetohydrodynamic simulations including ohmic dissipation and ambipolar diffusion. Without these effects, magnetic fields transport angular momentum so efficiently that no rotationally supported disk is formed even after the second collapse. Ohmic dissipation works only in a relatively high density region within the first core and suppresses angular momentum transport, enabling formation of a very small rotationally supported disk after the second collapse. With both ohmic dissipation and ambipolar diffusion, these effects work effectively in almost the entire region within the first core and significant magnetic flux loss occurs. As a result, a rotationally supported disk is formed even before a protostellar core forms. The size of the disk is still small, about 5 AU at the end of the first core phase, but this disk will grow later as gas accretion continues. Thus, the nonideal MHD effects can resolve the so-called magnetic braking catastrophe while keeping the disk size small in the early phase, which is implied from recent interferometric observations.

  12. LiteBIRD: a small satellite for the study of B-mode polarization and inflation from cosmic background radiation detection

    NASA Astrophysics Data System (ADS)

    Hazumi, M.; Borrill, J.; Chinone, Y.; Dobbs, M. A.; Fuke, H.; Ghribi, A.; Hasegawa, M.; Hattori, K.; Hattori, M.; Holzapfel, W. L.; Inoue, Y.; Ishidoshiro, K.; Ishino, H.; Karatsu, K.; Katayama, N.; Kawano, I.; Kibayashi, A.; Kibe, Y.; Kimura, N.; Koga, K.; Komatsu, E.; Lee, A. T.; Matsuhara, H.; Matsumura, T.; Mima, S.; Mitsuda, K.; Morii, H.; Murayama, S.; Nagai, M.; Nagata, R.; Nakamura, S.; Natsume, K.; Nishino, H.; Noda, A.; Noguchi, T.; Ohta, I.; Otani, C.; Richards, P. L.; Sakai, S.; Sato, N.; Sato, Y.; Sekimoto, Y.; Shimizu, A.; Shinozaki, K.; Sugita, H.; Suzuki, A.; Suzuki, T.; Tajima, O.; Takada, S.; Takagi, Y.; Takei, Y.; Tomaru, T.; Uzawa, Y.; Watanabe, H.; Yamasaki, N.; Yoshida, M.; Yoshida, T.; Yotsumoto, K.

    2012-09-01

    LiteBIRD [Lite (Light) satellite for the studies of B-mode polarization and Inflation from cosmic background Radiation Detection] is a small satellite to map the polarization of the cosmic microwave background (CMB) radiation over the full sky at large angular scales with unprecedented precision. Cosmological inflation, which is the leading hypothesis to resolve the problems in the Big Bang theory, predicts that primordial gravitational waves were created during the inflationary era. Measurements of polarization of the CMB radiation are known as the best probe to detect the primordial gravitational waves. The LiteBIRD working group is authorized by the Japanese Steering Committee for Space Science (SCSS) and is supported by JAXA. It has more than 50 members from Japan, USA and Canada. The scientific objective of LiteBIRD is to test all the representative inflation models that satisfy single-field slow-roll conditions and lie in the large-field regime. To this end, the requirement on the precision of the tensor-to-scalar ratio, r, at LiteBIRD is equal to or less than 0.001. Our baseline design adopts an array of multi-chroic superconducting polarimeters that are read out with high multiplexing factors in the frequency domain for a compact focal plane. The required sensitivity of 1.8μKarcmin is achieved with 2000 TES bolometers at 100mK. The cryogenic system is based on the Stirling/JT technology developed for SPICA, and the continuous ADR system shares the design with future X-ray satellites.

  13. Human radiation studies: Remembering the early years. Oral history of biochemist John Randolph Totter, Ph.D., January 23, 1995

    SciTech Connect

    1995-09-01

    This document is a transcript of an interview of Dr. John Randolph Tottler by representatives of the US DOE Office of Human Radiation Experiments. Dr. Tottler was selected for this interview because of his career with the Atomic Energy Commission Division of Biology and Medicine (DBM), particularly as its director from 1967 to 1972. After a short biographical sketch Dr. Tottler discusses his remembrances on a wide range topics including nucleic acid and leukemia research at Oak Ridge, AEC biochemistry training in South America, DBM`s research focus on radiation effects, early leadership of DBM, relations with the US Public Health Service, controversies on low-level radiation, iodine from fallout, on John Gofman, and Project Plowshare, funding for AEC Research Programs and for international research, testicular irradiation of prisoners in Washington State and Oregon, Plutonium injections, ethics of government radiation research, and opinions of public misperceptions about radiation and cancer.

  14. Low-Dose Consolidation Radiation Therapy for Early Stage Unfavorable Hodgkin Lymphoma

    SciTech Connect

    Torok, Jordan A.; Wu, Yuan; Prosnitz, Leonard R.; Kim, Grace J.; Beaven, Anne W.; Diehl, Louis F.; Kelsey, Chris R.

    2015-05-01

    Purpose: The German Hodgkin Study Group (GHSG) trial HD11 established 4 cycles of doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) and 30 Gy of radiation therapy (RT) as a standard for early stage (I, II), unfavorable Hodgkin lymphoma (HL). Additional cycles of ABVD may allow for a reduction in RT dose and improved toxicity profile. Methods and Materials: Patients treated with combined modality therapy at the Duke Cancer Institute for early stage, unfavorable HL by GHSG criteria from 1994 to 2012 were included. Patients who did not undergo post-chemotherapy functional imaging (positron emission tomography or gallium imaging) or who failed to achieve a complete response were excluded. Clinical outcomes were estimated using the Kaplan-Meier method. Late effects were also evaluated. Results: A total of 90 patients met inclusion criteria for analysis. Median follow-up was 5 years. Chemotherapy consisted primarily of ABVD (88%) with a median number of 6 cycles. The median dose of consolidation RT was 23.4 Gy. Four patients had relapses, 2 of which were in-field. Ten-year progression-free survival (PFS) and overall survival (OS) were 93% (95% confidence interval [CI]: 0.82-0.97) and 98% (95% CI: 0.92-0.99), respectively. For the subset of patients (n=46) who received 5 to 6 cycles of chemotherapy and ≤24 Gy, the 10-year PFS and OS values were 88% (95% CI: 70%-96%) and 98% (95% CI: 85% - 99%), respectively. The most common late effect was hypothyroidism (20%) with no cardiac complications. Seven secondary malignancies were diagnosed, with only 1 arising within the RT field. Conclusions: Lower doses of RT may be sufficient when combined with more than 4 cycles of ABVD for early stage, unfavorable HL and may result in a more favorable toxicity profile than 4 cycles of ABVD and 30 Gy of RT.

  15. Deciphering and dating the red panda's ancestry and early adaptive radiation of Musteloidea.

    PubMed

    Sato, Jun J; Wolsan, Mieczyslaw; Minami, Shinji; Hosoda, Tetsuji; Sinaga, Martua H; Hiyama, Kozue; Yamaguchi, Yasunori; Suzuki, Hitoshi

    2009-12-01

    information from all sampled genes yielded a approximately 42-Myr timescale to caniform evolution and provided evidence of five periods of increased diversification. The red panda's lineage and those of other extant musteloid families are estimated to have diverged during a 3-Myr interval from the mid-Early Oligocene to near the Early/Late Oligocene boundary. We present fossil evidence that extends the early adaptive radiation of the total clade of musteloids to the Eocene-Oligocene transition and also suggests Asia as a center of this radiation. PMID:19699810

  16. Deciphering and dating the red panda's ancestry and early adaptive radiation of Musteloidea.

    PubMed

    Sato, Jun J; Wolsan, Mieczyslaw; Minami, Shinji; Hosoda, Tetsuji; Sinaga, Martua H; Hiyama, Kozue; Yamaguchi, Yasunori; Suzuki, Hitoshi

    2009-12-01

    information from all sampled genes yielded a approximately 42-Myr timescale to caniform evolution and provided evidence of five periods of increased diversification. The red panda's lineage and those of other extant musteloid families are estimated to have diverged during a 3-Myr interval from the mid-Early Oligocene to near the Early/Late Oligocene boundary. We present fossil evidence that extends the early adaptive radiation of the total clade of musteloids to the Eocene-Oligocene transition and also suggests Asia as a center of this radiation.

  17. Recent radiation of Brachystelma and Ceropegia (Apocynaceae) across the Old World against a background of climatic change.

    PubMed

    Bruyns, P V; Klak, C; Hanáček, P

    2015-09-01

    The genera Brachystelma Sims and Ceropegia L. of the Ceropegieae (Apocynaceae-Asclepiadoideae) consist of ±320 species of geophytes and slender climbers with a tendency to stem-succulence in Ceropegia. They occur in and around the semi-arid, mainly tropical parts of the Old World. For 146 species (around half of the total) from most of the geographic range of the genera, we analysed data from two nuclear and five plastid regions. The evolution of Ceropegia is very complex, with at least 13 mostly well-supported lineages, one of which is sister to the ±350 species of stapeliads. Species of Brachystelma have evolved at least four times, with most of them nested within two separate major lineages. So, neither Brachystelma nor Ceropegia is monophyletic. We recover a broad trend, in two separate major lineages, from slender climbers to small, geophytic herbs. Several clades are recovered in which all species possess an underground tuber. Small, erect, non-climbing, geophytic species of Ceropegia with a tuber are nested among species of Brachystelma. Consequently, the distinctive tubular flowers used to define Ceropegia do not reflect relationships. This re-iterates the great floral plasticity in the Ceropegieae, already established for the stapeliads. Both major lineages exhibit a trend from tubular flowers with faint, often fruity odours, pollinated by very small Dipteran flies, to flatter flowers often with a bad odour, pollinated by larger flies. Most of the diversity in Brachystelma and Ceropegia is recent and arose within the last 3my against a background of increased aridification or extreme climatic variability during the Pliocene. In the ingroup, diversity is highest in Southern Africa, followed by Tropical East Africa and other arid parts of Africa, the Arabian Peninsula and India. Many disjunctions are revealed and these are best explained by recent, long distance dispersal. In Africa, the diversity arises from the presence of many different lineages over

  18. Recent radiation of Brachystelma and Ceropegia (Apocynaceae) across the Old World against a background of climatic change.

    PubMed

    Bruyns, P V; Klak, C; Hanáček, P

    2015-09-01

    The genera Brachystelma Sims and Ceropegia L. of the Ceropegieae (Apocynaceae-Asclepiadoideae) consist of ±320 species of geophytes and slender climbers with a tendency to stem-succulence in Ceropegia. They occur in and around the semi-arid, mainly tropical parts of the Old World. For 146 species (around half of the total) from most of the geographic range of the genera, we analysed data from two nuclear and five plastid regions. The evolution of Ceropegia is very complex, with at least 13 mostly well-supported lineages, one of which is sister to the ±350 species of stapeliads. Species of Brachystelma have evolved at least four times, with most of them nested within two separate major lineages. So, neither Brachystelma nor Ceropegia is monophyletic. We recover a broad trend, in two separate major lineages, from slender climbers to small, geophytic herbs. Several clades are recovered in which all species possess an underground tuber. Small, erect, non-climbing, geophytic species of Ceropegia with a tuber are nested among species of Brachystelma. Consequently, the distinctive tubular flowers used to define Ceropegia do not reflect relationships. This re-iterates the great floral plasticity in the Ceropegieae, already established for the stapeliads. Both major lineages exhibit a trend from tubular flowers with faint, often fruity odours, pollinated by very small Dipteran flies, to flatter flowers often with a bad odour, pollinated by larger flies. Most of the diversity in Brachystelma and Ceropegia is recent and arose within the last 3my against a background of increased aridification or extreme climatic variability during the Pliocene. In the ingroup, diversity is highest in Southern Africa, followed by Tropical East Africa and other arid parts of Africa, the Arabian Peninsula and India. Many disjunctions are revealed and these are best explained by recent, long distance dispersal. In Africa, the diversity arises from the presence of many different lineages over

  19. Chemical, physical and radiative properties of atmospheric aerosols measured at Mt. Lulin Atmospheric Background Station (LABS) in East Asia during biomass burning seasons (Invited)

    NASA Astrophysics Data System (ADS)

    Lin, N.; Lee, C.; Wang, S.; Chuang, M.; Chia, E.; Andrews, E.; Ogren, J. A.; Lin, J.; Hung, H.; Hsiao, T.; Liang, S.

    2013-12-01

    This paper presents the chemical, physical and radiative properties of atmospheric aerosols measured at the Lulin Atmospheric Background Station (LABS) which is located at Mt. Lulin (2,862 m MSL; 23o 28'07"N, 120o52'25"E) in central Taiwan, East Asia, and has been operated since 13 April, 2006. LABS is unique because its location and altitude enhances the global network of GAW (Global Atmosphere Watch) in the Southeast Asian region, where no high-elevation baseline station is available. Our site is located between the GAW Waliguan station (3,810 m) on the Tibetan plateau and the Mauna Loa Observatory (3,397m) in Hawaii. We will particularly focus on the results obtained during the spring season, when biomass burning activities prevail in northern Southeast Asia. Chemical characterization of fine and coarse aerosol particles, including water-soluble ions, organic and elemental carbon, and trace elements, will be presented. Aerosol optical properties, including scattering, absorption, extinction, single scattering albedo, Ångström exponent, and aerosol optical depth, as well as the derived radiative forcing efficiency, will be discussed. Results of cloud condensation nuclei measurements, made intermittently, will also be presented. Trajectory studies indicate that this site experiences a variety of air masses originating from contaminated and clean source regions, giving a distinctive contrast of atmospheric changes. To summarize the results, the maximum values (and monthly means) of these chemical, physical and radiative parameters generally occurred during spring time, especially in March, corresponding to prevailing biomass burning activities in SE Asia. Besides, LABS is also one of the supersites during the 2010-2013 spring campaigns of the Seven South East Asian Studies (7-SEAS) for studying the impact of biomass burning on cloud, atmospheric radiation, hydrological cycle, and regional climate over Southeast Asian region. Results of source (northern Thailand

  20. Soluble ferric iron as an effective protective agent against UV radiation: Implications for early life

    NASA Astrophysics Data System (ADS)

    Gómez, Felipe; Aguilera, Angeles; Amils, Ricardo

    2007-11-01

    Some recent MER Rover Opportunity results on ancient sedimentary rocks from Mars describe sandstones originated from the chemical weathering of olivine basalts by acidic waters [Squyres, S.W., Knoll, A.H., 2005. Earth Planet. Sci. Lett. 240, 1-10]. The absence of protective components in early Mars atmosphere forced any possible primordial life forms to deal with high doses of UV radiation. A similar situation occurred on the primitive Earth during the development of early life in the Archean [Berkner, L.V., Marshall, L.C., 1965. J. Atmos. Sci. 22 (3), 225-261; Kasting, J.F., 1993. Science 259, 920-926]. It is known that some cellular and/or external components can shield organisms from damaging UV radiation or quench its toxic effects [Olson, J.M., Pierson, B.K., 1986. Photosynth. Res. 9, 251-259; García-Pichel, F., 1998. Origins Life Evol. B 28, 321-347; Cockell, C., Rettberg, P., Horneck, G., Scherer, K., Stokes, M.D., 2003. Polar Biol. 26, 62-69]. The effectiveness of iron minerals for UV protection has also been reported [Phoenix, V.R., Konhauser, K.O., Adams, D.G., Bottrell, S.H., 2001. Geology 29 (9), 823-826], but nothing is known about the effect of iron in solution. Here we demonstrate the protective effect of soluble ferric iron against UV radiation on acidophilic photosynthetic microorganisms. These results offer an interesting alternative means of protection for life on the surface of early Mars and Earth, especially in light of the geochemical conditions in which the sedimentary minerals, jarosite and goethite, recently reported by the MER missions, were formed [Squyres, S.W., Arvidson, R.E., Bell III, J.F., Brückner, J., Cabrol, N.A., Calvin, W., Carr, M.H., Christensen, P.R., Clark, B.C., Crumpler, L., Des Marais, D.J., d'Uston, C., Economou, T., Farmer, J., Farrand, W., Folkner, W., Golombek, M., Gorevan, S., Grant, J.A., Greeley, R., Grotzinger, J., Haskin, L., Herkenhoff, K.E., Hviid, S., Johnson, J., Klingelhöfer, G., Knoll, A.H., Landis, G

  1. Human radiation studies: Remembering the early years: Oral history of pathologist Clarence Lushbaugh, M.D., conducted October 5, 1994

    SciTech Connect

    1995-04-01

    This report provides a transcript of an interview with Dr. Clarance Lushbaugh by representatives of the DOE Office of Human Radiation Experiments. Dr. Lushbaugh was chosen for this interview because of his research involving experimental use of irradiation with human beings at Los Alamos and at the Oak Ridge Institute of Nuclear Science (ORINS). After a brief biographical sketch Dr. Lushbaugh and his assistant Mrs. Ann Swipe defend their use of total body irradiation using the LETBI (Low Exposure Total Body Irradiation) and the LETBI (Medium Energy Total Body Irradiator). Dr. Lushbaugh also discusses his earlier experiments involving use of nitrogen mustards in chemotherapy application, his early interest in the LD50 for man, his early impressions of low-level spray radiation as introduced by Heubline, anedotal information for his duties a pathologist for Los Alamos, and his developing interest in establishing safer radiation limits for human exposure.

  2. Lack of Bystander Effects From High LET Radiation For Early Cytogenetic Endpoints.

    SciTech Connect

    Groesser, Torsten; Cooper, Brian; Rydberg, Bjorn

    2008-05-07

    The aim of this work was to study radiation-induced bystander effects for early cytogenetic end points in various cell lines using the medium transfer technique after exposure to high- and low-LET radiation. Cells were exposed to 20 MeV/ nucleon nitrogen ions, 968 MeV/nucleon iron ions, or 575 MeV/nucleon iron ions followed by transfer of the conditioned medium from the irradiated cells to unirradiated test cells. The effects studied included DNA double-strand break induction, {gamma}-H2AX focus formation, induction of chromatid breaks in prematurely condensed chromosomes, and micronucleus formation using DNA repair-proficient and -deficient hamster and human cell lines (xrs6, V79, SW48, MO59K and MO59J). Cell survival was also measured in SW48 bystander cells using X rays. Although it was occasionally possible to detect an increase in chromatid break levels using nitrogen ions and to see a higher number of {gamma}-H2AX foci using nitrogen and iron ions in xrs6 bystander cells in single experiments, the results were not reproducible. After we pooled all the data, we could not verify a significant bystander effect for any of these end points. Also, we did not detect a significant bystander effect for DSB induction or micronucleus formation in these cell lines or for clonogenic survival in SW48 cells. The data suggest that DNA damage and cytogenetic changes are not induced in bystander cells. In contrast, data in the literature show pronounced bystander effects in a variety of cell lines, including clonogenic survival in SW48 cells and induction of chromatid breaks and micronuclei in hamster cells. To reconcile these conflicting data, it is possible that the epigenetic status of the specific cell line or the precise culture conditions and medium supplements, such as serum, may be critical for inducing bystander effects.

  3. Introducing CoDa (Cosmic Dawn): Radiation-Hydrodynamics of Galaxy Formation in the Early Universe

    NASA Astrophysics Data System (ADS)

    Ocvirk, Pierre; Gillet, Nicolas; Shapiro, Paul; Aubert, Dominique; Iliev, Ilian; Romain, Teyssier; Yepes, Gustavo; Choi, Jun-hwan; Sullivan, David; Knebe, Alexander; Gottloeber, Stefan; D'Aloisio, Anson; Park, Hyunbae; Hoffman, Yehuda

    2015-08-01

    CoDa (Cosmic Dawn) is the largest fully coupled radiation hydrodynamics simulation of the reionization of the local Universe to date. It was performed using RAMSES-CUDATON running on 8192 nodes (i.e. 8192 GPUs) on the titan supercomputer at Oak Ridge National Laboratory to simulate a 64 h-1Mpc side box down to z=4.23. In this simulation, reionization proceeds self-consistently, driven by stellar radiation. We compare the simulation's reionization history, ionizing flux density, the cosmic star formation history and the CMB Thompson scattering optical depth with their observational values. Luminosity functions are also in rather good agreement with high redshift observations, although very bright objects (MAB1600 < -21) are overabundant in CoDa. We investigate the evolution of the intergalactic medium, and find that gas filaments present a sheathed structure, with a hot envelope surrounding a cooler core. They are however not able to self-shield, while regions denser than 10^-4.5 H atoms per comoving h^-3cm^3 are. Haloes below M ˜ 3.10^9 M⊙ are severely affected by the expanding, rising UV background: their ISM is quickly photo-heated to temperatures above our star formation threshold and therefore stop forming stars after local reionization has occured. Overall, the haloes between 10^(10-11) M⊙ dominate the star formation budget of the box for most of the Epoch of Reionization. Several additional studies will follow, looking for instance at environmental effects on galaxy properties, and the regimes of accretion.

  4. An evaluation of early countermeasures to reduce the risk of internal radiation exposure after the Fukushima nuclear incident in Japan.

    PubMed

    Nomura, Shuhei; Tsubokura, Masaharu; Gilmour, Stuart; Hayano, Ryugo S; Watanabe, Yuni N; Kami, Masahiro; Kanazawa, Yukio; Oikawa, Tomoyoshi

    2016-05-01

    After a radiation-release incident, intake of radionuclides in the initial stage immediately following the incident may be the major contributor to total internal radiation exposure for individuals in affected areas. However, evaluation of early internal contamination risk is greatly lacking. This study assessed the relationship between initial stage evacuation/indoor sheltering and internal radiation contamination levels 4 months after the 2011 Fukushima nuclear incident in Japan and estimated potential pathways of the contamination. The study population comprised 525 participants in the internal radiation screening program at Minamisoma Municipal General Hospital, 23 km north of the Fukushima nuclear plant. The analysed dataset included the results of a screening performed in July 2011, 4 months after the incident, and of a questionnaire on early-incident response behaviours, such as sheltering indoors and evacuations, completed by participants. Association between such early countermeasures and internal contamination levels of cesium-134 were assessed using Tobit multiple regression analyses. Our study shows that individuals who evacuated to areas outside Fukushima Prefecture had similar contamination levels of cesium-134 to individuals who stayed in Fukushima (relative risk: 0.86; 95% confidence interval: 0.74-0.99). Time spent outdoors had no significant relationship with contamination levels. The effects of inhalation from radiological plumes released from the nuclear plant on total internal radiation contamination might be so low as to be undetectable by the whole-body counting unit used to examine participants. Given the apparent limited effectiveness of evacuation and indoor sheltering on internal contamination, the decision to implement such early responses to a radiation-release incident should be made by carefully balancing their potential benefits and health risks.

  5. Role of Early Proctoscopy in Predicting Late Symptomatic Proctitis After External Radiation Therapy for Prostate Carcinoma

    SciTech Connect

    Campostrini, Franco; Musola, Renato; Marchiaro, Giuseppe; Lonardi, Federico; Verlato, Giuseppe

    2013-03-15

    Purpose: To determine whether acute radiation-proctitis, diagnosed by proctoscopy after radiation therapy for prostate cancer, can predict late clinical proctitis. Methods and Materials: A prospective study of 130 patients who underwent external radiation therapy (RT) for stage T1 to T4 prostate cancer between 1997 and 2008 was performed. Treatments were conventional (2-dimensional [2D]) in 61 patients and 3D conformal in 69, with a median target dose of 72 Gy (70-74 Gy). Within 1 week after RT, proctoscopy was performed to detect possible acute endoscopic proctitis (AEP). Acute clinical proctitis (ACP) and late clinical proctitis (LCP) were also evaluated. The median follow-up was 84 months (20-180 months). The influence of AEP and ACP on LCP occurrence was studied using the Cox model controlling for age, dose, prostatectomy, RT technique (2D vs 3D), and hormone therapy. Results: AEP was detected in 15 patients (11.5%) and ACP in 67 (51.5%); in 13 cases (10%) AEP and ACP occurred simultaneously. Thirty-five cases of LCP were recorded. The 5-year probability of developing LCP was highest in patients with AEP and ACP (77%, 95% confidence interval [CI] 53%-94%) and lowest in asymptomatic patients (14%, 95% CI 7%-26%; P<.001). Compared to asymptomatic patients, the 5-year probability also was slightly increased in patients with ACP only (26%, 95% CI 16%-40%; P=.052). In multivariable analysis, the combination of AEP and ACP was the main predictor of LCP: compared to asymptomatic patients, the hazard ratio was 5.6 (2.1-15.2) in patients with AEP plus ACP (P=.001) and 2.1 (0.9-4.9) in those with ACP only (P=.103). Conclusions: In patients with AEP and ACP, the risk of LCP was more than 5-fold increased compared to those who were asymptomatic, while a much smaller increase in risk occurred in patients with ACP only. Early proctoscopy can provide valuable information regarding the likelihood of late proctitis.

  6. Measurements of Rn-222, Rn-220 and their decay products in the environmental air of the high background radiation areas in Yangjiang, China.

    PubMed

    Yuan, Y; Morishima, H; Shen, T; Koga, T; Wei, L; Sugahara, T

    2000-10-01

    For the renewal of dose estimation from internal irradiation in the high background radiation areas (HBRA) of Yangjiang, the measurements of radon, thoron and their decay products in the environmental air were conducted, including: (1) integrating measurements of Rn-222 and Rn-220 concentrations; (2) eqilibrium factor F for Rn-222 and alpha-potential energy value of Rn-220; (3) external gamma radiation in places where radon measurements were undertaken; (4) cumulative exposure to indoor radon for each family in a case-control study on lung cancer. The Rn-Tn cup monitor method was used for the integrating measurement of Rn-222 and Rn-220 concentration. An alpha track detector was used for the integration measurement of Rn-222 concentration in the case-control study on lung cancer. The results of measurements show that although the investigated areas are located between the Equator and the Tropic of Cancer, and that people live in well-ventilated dwellings, the concentrations of radon, especially of Rn-220 are significantly higher in the indoor air of HBRA than those in the control area. The value of equilibrium factors for Rn-222, the alpha potential energy of decay products from Rn-222 and Rn-220 are determined.

  7. The microwave background anisotropies: observations.

    PubMed

    Wilkinson, D

    1998-01-01

    Most cosmologists now believe that we live in an evolving universe that has been expanding and cooling since its origin about 15 billion years ago. Strong evidence for this standard cosmological model comes from studies of the cosmic microwave background radiation (CMBR), the remnant heat from the initial fireball. The CMBR spectrum is blackbody, as predicted from the hot Big Bang model before the discovery of the remnant radiation in 1964. In 1992 the cosmic background explorer (COBE) satellite finally detected the anisotropy of the radiation-fingerprints left by tiny temperature fluctuations in the initial bang. Careful design of the COBE satellite, and a bit of luck, allowed the 30 microK fluctuations in the CMBR temperature (2.73 K) to be pulled out of instrument noise and spurious foreground emissions. Further advances in detector technology and experiment design are allowing current CMBR experiments to search for predicted features in the anisotropy power spectrum at angular scales of 1 degrees and smaller. If they exist, these features were formed at an important epoch in the evolution of the universe--the decoupling of matter and radiation at a temperature of about 4,000 K and a time about 300,000 years after the bang. CMBR anisotropy measurements probe directly some detailed physics of the early universe. Also, parameters of the cosmological model can be measured because the anisotropy power spectrum depends on constituent densities and the horizon scale at a known cosmological epoch. As sophisticated experiments on the ground and on balloons pursue these measurements, two CMBR anisotropy satellite missions are being prepared for launch early in the next century.

  8. Radiation and functional diversification of alpha keratins during early vertebrate evolution.

    PubMed

    Vandebergh, Wim; Bossuyt, Franky

    2012-03-01

    The conquest of land was arguably one of the most fundamental ecological transitions in vertebrates and entailed significant changes in skin structure and appendages to cope with the new environment. In extant tetrapods, the rigidity of the integument is largely created by type I and type II keratins, which are structural proteins essential in forming a strong cytoplasmic network. It is expected that such proteins have undergone fundamental changes in both stem and crown tetrapods. Here, we integrate genomic, phylogenetic, and expression data in a comprehensive study on the early evolution and functional diversification of tetrapod keratins. Our analyses reveal that all type I and type II tetrapod keratins evolved from only two genes that were present in the ancestor of extant vertebrates. Subsequently, the water-to-land transition in the stem lineage of tetrapods was associated with a major radiation and functional diversification of keratin genes. These duplications acquired functions that serve rigidity in integumental hard structures and were the prime for subsequent independent keratin diversification in tetrapod lineages. PMID:22046002

  9. Supradiaphragmatic early stage Hodgkin's disease: does mantle radiation therapy still have a role?

    PubMed

    Frezza, G; Barbieri, E; Zinzani, P L; Babini, L; Tura, S

    1996-01-01

    Extended field radiation therapy represents the main therapeutic option in early stage Hodgkin's disease with favorable prognostic features. Its role however has recently been criticized, mainly due to the high incidence of late complications in irradiated tissues. Furthermore, surgical staging, which in the opinion of many is mandatory for proper selection of patients for radiotherapy alone, has a well-known morbidity, and splenectomy has been associated with a high risk of secondary leukemias. Lastly, the failure rate after radiotherapy only is not negligible and second-line treatment is not always successful. A review of our experience and of the recent literature has allowed us to refute these objections. The results of radiotherapy, when properly performed, are highly reliable and have been reproducible in many Institutions. Chemotherapy alone cannot yet be regarded as an alternative to radiotherapy in these patients since data reported on this issue are conflicting. Present knowledge regarding the relationship between clinical features and the risk of occult subdiaphragmatic spread allows patients with localized disease to be selected without surgical staging; the results of radiotherapy in clinically staged patients confirm this statement. Concern for the late effects in irradiated tissues is justified, and future efforts should be directed at reducing the toxicity of this treatment. Associating a short chemotherapy course with low-dose radiotherapy to involved sites could help to achieve this goal.

  10. Supradiaphragmatic early stage Hodgkin's disease: does mantle radiation therapy still have a role?

    PubMed

    Frezza, G; Barbieri, E; Zinzani, P L; Babini, L; Tura, S

    1996-01-01

    Extended field radiation therapy represents the main therapeutic option in early stage Hodgkin's disease with favorable prognostic features. Its role however has recently been criticized, mainly due to the high incidence of late complications in irradiated tissues. Furthermore, surgical staging, which in the opinion of many is mandatory for proper selection of patients for radiotherapy alone, has a well-known morbidity, and splenectomy has been associated with a high risk of secondary leukemias. Lastly, the failure rate after radiotherapy only is not negligible and second-line treatment is not always successful. A review of our experience and of the recent literature has allowed us to refute these objections. The results of radiotherapy, when properly performed, are highly reliable and have been reproducible in many Institutions. Chemotherapy alone cannot yet be regarded as an alternative to radiotherapy in these patients since data reported on this issue are conflicting. Present knowledge regarding the relationship between clinical features and the risk of occult subdiaphragmatic spread allows patients with localized disease to be selected without surgical staging; the results of radiotherapy in clinically staged patients confirm this statement. Concern for the late effects in irradiated tissues is justified, and future efforts should be directed at reducing the toxicity of this treatment. Associating a short chemotherapy course with low-dose radiotherapy to involved sites could help to achieve this goal. PMID:8641642

  11. Polonium-Lead Extractions to Determine the Best Method for the Quantification of Clean Lead Used in Low-Background Radiation Detectors

    SciTech Connect

    Miley, Sarah M.; Payne, Rosara F.; Schulte, Shannon M.; Finn, Erin C.

    2009-12-01

    Radiation detectors used to search for the existence of exceptionally rare phenomena, such as double-beta decay and dark matter interactions, as well as tiny traces of environmental radioactivity, require the elimination of background signals. Modern detection systems created from ultra pure materials and operated deep underground may be sensitive enough to "see" these rare phenomena, but background activity in Pb gamma-ray shielding could still be a critical stumbling block owing to alpha and beta emissions of Pb, Bi, and Po in the mass 210 chain. To minimize the probability of overwhelming activity from Pb, the alpha activity of 210Pb is quantified. However, a reliable quantification procedure that does not require large volumes of chemicals has not yet been established. Two procedures created for this purpose have been tested for the quantification of alpha activity in lead. Both procedures were designed to start with less than 10g Pb samples to reduce reagents needed and combined precipitation with column separation to isolate 210Pb, followed by alpha spectrometry. One procedure shows promise for obtaining high recoveries and good separation.

  12. Sci—Fri AM: Mountain — 04: Label-free Raman spectroscopy of single tumour cells detects early radiation-induced glycogen synthesis associated with increased radiation resistance

    SciTech Connect

    Matthews, Q; Lum, JJ; Isabelle, M; Harder, S; Jirasek, A; Brolo, AG

    2014-08-15

    Purpose: To use label-free Raman spectroscopy (RS) for early treatment monitoring of tumour cell radioresistance. Methods: Three human tumour cell lines, two radioresistant (H460, SF{sub 2} = 0.57 and MCF7, SF{sub 2} = 0.70) and one radiosensitive (LNCaP, SF{sub 2} = 0.36), were irradiated with single fractions of 2, 4, 6, 8 or 10 Gy. In additional experiments, H460 and MCF7 cells were irradiated under co-treatment with the anti-diabetic drug metformin, a known radiosensitizing agent. Treated and control cultures were analyzed with RS daily for 3 days post-treatment. Single-cell Raman spectra were acquired from 20 live cells per sample, and experiments were repeated in triplicate. The combined data sets were analyzed with principal component analysis using standard algorithms. Cells from each culture were also subjected to standard assays for viability, proliferation, cell cycle, and radiation clonogenic survival. Results: The radioresistant cells (H460, MCF7) exhibited a RS molecular radiation response signature, detectable as early as 1 day post-treatment, of which radiation-induced glycogen synthesis is a significant contributor. The radiosensitive cells (LNCaP) exhibited negligible glycogen synthesis. Co-treatment with metformin in MCF7 cells blocked glycogen synthesis, reduced viability and proliferation, and increased radiosensitivity. Conversely, metformin co-treatment in H460 cells did not produce these same effects; importantly, both radiation-induced synthesis of glycogen and radiosensitivity were unaffected. Conclusions: Label-free RS can detect early glycogen synthesis post-irradiation, a previously undocumented metabolic mechanism associated with tumour cell radioresistance that can be targeted to increase radiosensitivity. RS monitoring of intratumoral glycogen may provide new opportunities for personalized combined modality radiotherapy treatments.

  13. Ray Guns and Radium: Radiation in the Public Imagination as Reflected in Early American Science Fiction

    ERIC Educational Resources Information Center

    Slaughter, Aimee

    2014-01-01

    The 1920s and 1930s were a period which saw great popular interest in radiation and radioactivity in America, and the establishment of a new genre of pulp literature, science fiction. Radiation was prevalent in American popular culture at the time, and sf stories were dependent upon radiation for much of their color and excitement. In this case…

  14. Risk prediction for early-onset gastric carcinoma: a case-control study of polygenic gastric cancer in Han Chinese with hereditary background

    PubMed Central

    Yuan, Jiajia; Li, Yanyan; Tian, Tiantian; Li, Na; Zhu, Yan; Zou, Jianling; Gao, Jing; Shen, Lin

    2016-01-01

    Recent genomewide studies have identified several germline variations associated with gastric cancer. The aim of the present study was to identify, in a Chinese Han population, the individual and combined effects of those single nucleotide polymorphisms (SNPs) that increase the risk of early-onset gastric cancer. We conducted a case-control study comprising 116 patients with gastric cancer as well as 102 sex- and age-matched controls and confirmed that the SNPs MUC1 (mucin 1) rs9841504 and ZBTB20 (zinc finger and BTB domain containing 20) rs4072037 were associated with an increased gastric cancer risk. Of the 116 patients diagnosed with cancer, 65 had at least 1 direct lineal relative with carcinoma of the digestive system or breast/ovarian cancer. These 65 had another 4 SNPs associated with gastric cancer susceptibility: PSCA (prostate stem cell antigen) rs2294008, PLCE1 (phospholipase C epsilon 1) rs2274223, PTGER4/PRKAA1 (prostaglandin E receptor 4/protein kinase AMP-activated catalytic subunit alpha 1) rs13361707, and TYMS (thymidylate synthetase) rs2790. However, each of these low-penetrance susceptibility polymorphisms alone is not considered influential enough to predict the absolute risk of early-onset gastric cancer. Thus we decided to study different combinations of polygenes as they affected for our population. Those subjects with both the risk alleles MUC1 rs9841504 and ZBTB20 rs4072037 had a greater than 3-fold increased risk of gastric cancer. Also those with a hereditary background including the risk alleles PLCE1 rs2274223 and PTGER4/PRKAA1 rs13361707 were 3 times more susceptible to cardia cancer than those without. These findings show that the study of combined polymorphisms, instead of single low-penetrance variations in susceptibility, may lead to a high-risk classification for a specific population. PMID:27127881

  15. Risk prediction for early-onset gastric carcinoma: a case-control study of polygenic gastric cancer in Han Chinese with hereditary background.

    PubMed

    Yuan, Jiajia; Li, Yanyan; Tian, Tiantian; Li, Na; Zhu, Yan; Zou, Jianling; Gao, Jing; Shen, Lin

    2016-06-01

    Recent genomewide studies have identified several germline variations associated with gastric cancer. The aim of the present study was to identify, in a Chinese Han population, the individual and combined effects of those single nucleotide polymorphisms (SNPs) that increase the risk of early-onset gastric cancer. We conducted a case-control study comprising 116 patients with gastric cancer as well as 102 sex- and age-matched controls and confirmed that the SNPs MUC1 (mucin 1) rs9841504 and ZBTB20 (zinc finger and BTB domain containing 20) rs4072037 were associated with an increased gastric cancer risk. Of the 116 patients diagnosed with cancer, 65 had at least 1 direct lineal relative with carcinoma of the digestive system or breast/ovarian cancer. These 65 had another 4 SNPs associated with gastric cancer susceptibility: PSCA (prostate stem cell antigen) rs2294008, PLCE1 (phospholipase C epsilon 1) rs2274223, PTGER4/PRKAA1 (prostaglandin E receptor 4/ protein kinase AMP-activated catalytic subunit alpha 1) rs13361707, and TYMS (thymidylate synthetase) rs2790. However, each of these low-penetrance susceptibility polymorphisms alone is not considered influential enough to predict the absolute risk of early-onset gastric cancer. Thus we decided to study different combinations of polygenes as they affected for our population. Those subjects with both the risk alleles MUC1 rs9841504 and ZBTB20 rs4072037 had a greater than 3-fold increased risk of gastric cancer. Also those with a hereditary background including the risk alleles PLCE1 rs2274223 and PTGER4/PRKAA1 rs13361707 were 3 times more susceptible to cardia cancer than those without. These findings show that the study of combined polymorphisms, instead of single low-penetrance variations in susceptibility, may lead to a high-risk classification for a specific population. PMID:27127881

  16. Second Malignancies After Adjuvant Radiation Therapy for Early Stage Breast Cancer: Is There Increased Risk With Addition of Regional Radiation to Local Radiation?

    SciTech Connect

    Hamilton, Sarah Nicole; Tyldesley, Scott; Li, Dongdong; Olson, Robert; McBride, Mary

    2015-04-01

    Purpose: This study was undertaken to determine whether there was an increased risk of second malignancies (SM), particularly lung cancer, in early stage breast cancer patients treated with the addition of nodal fields to breast and/or chest wall radiation therapy (RT). Materials and Methods: Subjects were stage I/II female breast cancer patients 20 to 79 years of age, diagnosed between 1989 and 2005 and treated with adjuvant RT at our institution. Patients were included if they survived and did not have SM within 3 years of diagnosis. Standardized incidence ratios (SIR) with 95% confidence intervals (CI) were calculated to compare SM incidence to cancer incidence in the general sex- and age-matched populations. Secondary malignancy risks in patients treated with local RT (LRT) to the breast/chest wall were compared to those in patients treated with locoregional RT (LRRT) to the breast/chest wall and regional nodes, using multivariate regression analysis (MVA) to account for covariates. Results: The cohort included 12,836 patients with a median follow-up of 8.4 years. LRRT was used in 18% of patients. The SIR comparing patients treated with LRT to the general population was 1.29 (CI: 1.21-1.38). No statistically significant increased incidence of in-field malignancies (SIR, 1.04; CI: 0.87-1.23) and lung cancers (SIR, 1.06; CI: 0.88-1.26) was detected. The SIR comparing patients treated with LRRT to the general population was 1.39 (CI: 1.17-1.64). No statistically significant increased incidence of in-field malignancies (SIR, 1.26; CI: 0.77-1.94) and lung cancers (SIR, 1.27; CI: 0.76-1.98) was detected. On MVA comparing LRRT to LRT, the adjusted hazard ratio was 1.20 for in-field malignancies (CI: 0.68-2.16) and 1.26 for lung cancer (CI: 0.67-2.36). The excess attributable risk (EAR) to regional RT was 3.1 per 10,000 person years (CI: −8.7 to 9.9). Conclusions: No statistically significant increased risk of second malignancy was detected after LRRT relative to

  17. Late Ordovician graptolite mass mortality and subsequent early silurian re-radiation

    NASA Astrophysics Data System (ADS)

    Berry, William B. N.; Wilde, Pat; Quinby-Hunt, Mary S.

    Late Ordovician graptolite mass mortality has been examined closely in only a few continuous stratal succession. These sections include those at Dob's Linn, Scotland; Anhui, China; and Mirny Creek, USSR. Correlations among these areas are not precise; however, many characteristic Late Ordovician graptolites appear to persist longer in the Anhui area than at either Dob's Linn or Mirny Creek. Graptolites disappear from the stratigraphic record more sharply at Dob's Linn than at the other localities. Lithologic and chemical aspects of the strata at each locality suggest that a significant environmental change occurred at the stratigraphic position at which the graptolites disappeared. That change appears to reflect both a diminution and a deterioration in environmental conditions under which the graptolites previously had flourished. The optimal conditions for graptolites appear to have been in low oxygen but bacteria-rich waters similar to those found in the modern Eastern Tropical Pacific. Areal reduction in those environments as well as reduction in food resources preferred by graptolites resulted in diminished graptolite populations. These reductions took place gradually in many parts of the world, generally commencing in high latitudes. The final Late Ordovician mortality, in the Tropics, may have been the result of introduction of toxins to graptolites or their food supply by local overturn and increased vertical advection from moderate depths. The timing of such events in the Tropics is non-synchronous, suggesting local environmental influences. Geochemical and lithologic evidence links the Late Ordovician graptolite mass extinction to progressive latitudinal habitat destruction commensurate with the final pulse of the Late Ordovician glaciation. Re-radiation of the surviving taxa in the Early Silurian followed deglaciation and redevelopment of marine environments preferred by graptolites.

  18. Aspirin and Statin Nonuse Associated With Early Biochemical Failure After Prostate Radiation Therapy

    SciTech Connect

    Zaorsky, Nicholas G.; Buyyounouski, Mark K.; Li, Tianyu; Horwitz, Eric M.

    2012-09-01

    Purpose: To present the largest retrospective series investigating the effect of aspirin and statins, which are hypothesized to have antineoplastic properties, on biochemical failure (nadir plus 2 ng/mL) after prostate radiation therapy (RT). Methods and Materials: Between 1989 and 2006, 2051 men with clinically localized prostate cancer received definitive RT alone (median dose, 76 Gy). The rates of aspirin use and statin use (defined as any use at the time of RT or during follow-up) were 36% and 34%, respectively. The primary endpoint of the study was an interval to biochemical failure (IBF) of less than 18 months, which has been shown to be the single strongest predictor of distant metastasis, prostate cancer survival, and overall survival after RT. Patient demographic characteristics and tumor staging factors were assessed with regard to associations with the endpoint. Univariate analysis was performed with the {chi}{sup 2} test for categorical variables and the Wilcoxon test for continuous variables. Multivariable analysis was performed with a multiple logistic regression. Results: The median follow-up was 75 months. Univariate analysis showed that an IBF of less than 18 months was associated with aspirin nonuse (P<.0001), statin nonuse (P<.0001), anticoagulant nonuse (P=.0006), cardiovascular disease (P=.0008), and prostate-specific antigen (continuous) (P=.008) but not with Gleason score, age, RT dose, or T stage. On multivariate analysis, only aspirin nonuse (P=.0012; odds ratio, 2.052 [95% confidence interval, 1.328-3.172]) and statin nonuse (P=.0002; odds ratio, 2.465 [95% confidence interval, 1.529-3.974]) were associated with an IBF of less than 18 months. Conclusions: In patients who received RT for prostate cancer, aspirin or statin nonuse was associated with early biochemical failure, a harbinger of distant metastasis and death. Further study is needed to confirm these findings and to determine the optimal dosing and schedule, as well as the relative

  19. The 60-μm extragalactic background radiation intensity, dust-enshrouded active galactic nuclei and the assembly of groups and clusters of galaxies

    NASA Astrophysics Data System (ADS)

    Blain, A. W.; Phillips, T. G.

    2002-06-01

    Submillimetre- (submm-) wave observations have revealed a cosmologically significant population of high-redshift dust-enshrouded galaxies. The form of evolution inferred for this population can be reconciled easily with COBE FIRAS and DIRBE measurements of the cosmic background radiation (CBR) intensity at wavelengths longer than ~100μm. At shorter wavelengths, however, the 60-μm CBR intensity reported by Finkbeiner, Davis & Schlegel is less easily accounted for. Lagache et al. have proposed that this excess CBR emission is a warm Galactic component, and the detection of the highest-energy γ-rays from blazars limits the CBR intensity at these wavelengths, but here we investigate possible sources of this excess CBR emission, assuming that it has a genuine extragalactic origin. We propose and test three explanations, each involving additional populations of luminous, evolving galaxies not readily detected in existing submm-wave surveys. First, an additional population of dust-enshrouded galaxies with hot dust temperatures, perhaps dust-enshrouded, Compton-thick active galactic nuclei (AGN) as suggested by recent deep Chandra surveys. Secondly, a population of dusty galaxies with temperatures more typical of the existing submm-selected galaxies, but at relatively low redshifts. These could plausibly be associated with the assembly of groups and clusters of galaxies. Thirdly, a population of low-luminosity, cool, quiescent spiral galaxies. Hot AGN sources and the assembly of galaxy groups can account for the excess 60-μm background. There are significant problems with the cluster assembly scenario, in which too many bright 60-μm IRAS sources are predicted. Spiral galaxies have the wrong spectral energy distributions to account for the excess. Future wide-field far-infrared (IR) surveys at wavelengths of 70 and 250μm using the SIRTF and Herschel space missions will sample representative volumes of the distant Universe, allowing any hot population of dusty AGNs and

  20. Clinical studies on the use of radiation therapy as primary treatment of early breast cancer

    SciTech Connect

    Harris, J.R.; Beadle, G.F.; Hellman, S.

    1984-02-01

    The treatment of operable breast cancer by primary radiation therapy instead of mastectomy is undergoing evaluation in the United States and Europe. Retrospective studies of patients treated by primary radiation therapy show that local control and survival rates are comparable to those obtained by mastectomy. Detailed analysis of local failure following primary radiation therapy indicates the importance of excisional biopsy of the primary tumor, moderate doses of radiation to the breast and draining lymph node areas, and the use of a boost to the primary tumor area in maximizing local control. Further, the judicious use of local excision combined with meticulous radiotherapy technique yields highly satisfactory results for the majority of treated patients. Preliminary results from prospective trials also indicate that primary radiation therapy provides both local control and survival rates equivalent to mastectomy. Primary radiation therapy is becoming an increasingly important alternative to mastectomy where surgical and radiotherapeutic expertise are available to optimize both local tumor control and the final cosmetic outcome.

  1. Analysis of internal exposure associated with consumption of crops and groundwater from the high background radiation area of Mrima Hill, Kenya.

    PubMed

    Chege, M W; Hashim, N O; Merenga, A S; Tschiersch, J

    2015-11-01

    Specific concentrations of (226)Ra, (232)Th and (40)K were measured in cassava tubers, cassava leaves and groundwater obtained from the high background radiation area of Mrima hill and used in the evaluation of the ingested dose. Cassava tubers, cassava leaves and groundwater registered average (226)Ra concentrations of 60 ± 5, 141 ± 11 and 4.3 ± 0.3 Bq kg(-1), respectively. (232)Th was not detected in cassava leaves although it was present in cassava tubers as well as in groundwater in average concentrations of 35.3±61.5 and 2.0±0.1 Bq kg(-1), respectively. (40)K was present in all samples in average concentrations of 842±539 Bq kg(-1) in cassava tubers, 1708 ± 552 Bq kg(-1) in cassava leaves and 91.4 Bq kg(-1) in groundwater. The total annual effective dose due to ingestion was found to be 7.9 mSv y(-1) of which 2.4 mSv y(-1) was due to cassava tubers, 3.8 mSv y(-1) due to cassava leaves and 1.7 mSv y(-1) due to water.

  2. Ray Guns and Radium: Radiation in the Public Imagination as Reflected in Early American Science Fiction

    NASA Astrophysics Data System (ADS)

    Slaughter, Aimee

    2014-03-01

    The 1920s and 1930s were a period which saw great popular interest in radiation and radioactivity in America, and the establishment of a new genre of pulp literature, science fiction. Radiation was prevalent in American popular culture at the time, and sf stories were dependent upon radiation for much of their color and excitement. In this case study of stories in Amazing Stories and Astounding Stories, two of the leading sf pulps, the connections between actual scientific ideas and discoveries and sf plots and imagery are analyzed, demonstrating the general optimistic belief in the possibilities of scientifically-controlled radiation.

  3. IEEE Nuclear and Space Radiation Effects Conference: Notes on the Early Conferences

    NASA Technical Reports Server (NTRS)

    Pellish, Jonathan A.; Galloway, Kenneth F.

    2013-01-01

    This paper gathers the remembrances of several key contributors who participated in the earliest Institute of Electrical and Electronics Engineers (IEEE) Nuclear and Space Radiation Effects Conferences (NSREC).

  4. Background sources in optical communications

    NASA Technical Reports Server (NTRS)

    Vilnrotter, V. A.

    1983-01-01

    The characterization and measurement of background radiation relevant to optical communications system performance is addressed. The necessary optical receiver parameters are described, and radiometric concepts required for the calculation of collected background power are developed. The most important components of optical background power are discussed, and their contribution to the total collected background power in various communications scenarios is examined.

  5. Capabilities of the cosmic background explorer

    NASA Technical Reports Server (NTRS)

    Mather, J. C.

    1987-01-01

    The cosmic background explorer, now being redesigned for a launch on a Delta rocket in 1989, will carry three instruments to measure the cosmic infrared and microwave background radiation and other diffuse sources from 1 micron to 1 cm wavelength. These instruments will be orders of magnitude more sensitive and accurate than previous equipment and will help determine the structure of the early universe. The instruments are (1) an absolute spectrophotometer, covering 100 microns to 1 cm, (2) an absolute infrared radiometer covering 1 to 300 microns, and (3) differential microwave radiometers at 32, 53, and 90 GHz. They will measure the large scale anisotropy and the spectrum of the 3 K cosmic background, and search for the extragalactic infrared background, to a sensitivity limited by the astrophysical environment. The first two instruments require liquid helium cooling, limiting their lifetime to about 14 months.

  6. Human radiation studies: Remembering the early years. Oral history of Merril Eisenbud, January 26, 1995

    SciTech Connect

    1995-05-01

    Merril Eisenbud was interviewed on January 26, 1995 by representatives of the US DOE Office of Human Radiation Experiments. Following a brief biographical sketch, Mr. Eisenbud relates his remembrances as the AEC`s first industrial hygienist, the setting up of AEC`s Health and Safety Laboratory, monitoring radioactive fallout, and use or exposure of humans to radiation.

  7. Sensitivity of the early life stages of macroalgae from the Northern Hemisphere to ultraviolet radiation.

    PubMed

    Roleda, Michael Y; Wiencke, Christian; Hanelt, Dieter; Bischof, Kai

    2007-01-01

    The reproductive cells of macroalgae are regarded as the life history stages most susceptible to various environmental stresses, including UV radiation (UVR). UVR is proposed to determine the upper depth distribution limit of macroalgae on the shore. These hypotheses were tested by UV-exposure experiments, using spores and young thalli of the eulittoral Rhodophyceae Mastocarpus stellatus and Chondrus crispus and various sublittoral brown macroalgae (Phaeophyceae) with different depth distribution from Helgoland (German Bight) and Spitsbergen (Arctic). In spores, the degree of UV-induced inhibition of photosynthesis is lower in eulittoral species and higher in sublittoral species. After UV stress, recovery of photosynthetic capacity is faster in eulittoral compared to sublittoral species. DNA damage is lowest while repair of DNA damage is highest in eulittoral compared to sublittoral species. When the negative impact of UVR prevails, spore germination is inhibited. This is observed in deep water kelp species whereas the same UVR doses do not inhibit germination of shallow water kelp species. A potential acclimation mechanism to increase UV tolerance of brown algal spores is the species-specific ability to increase the content of UV-absorbing phlorotannins in response to UV-exposure. Growth rates of young Mastocarpus and Chondrus gametophytes exposed to experimental doses of UVR are not affected while growth rates of all young kelp sporophytes exposed to UVR are significantly lowered. Furthermore, morphological UV damage in Laminaria ochroleuca includes tissue deformation, lesion, blistering and thickening of the meristematic part of the lamina. The sensitivity of young sporophytes to DNA damage is correlated with thallus thickness and their optical characteristics. Growth rate is an integrative parameter of all physiological processes in juvenile plants. UV inhibition of growth may affect the upper distribution depth limit of adult life history stages. Juveniles

  8. Effects of terahertz radiation at atmospheric oxygen frequency of 129 GHz on blood nitrite concentrations under conditions of different types of stress against the background of administration of nonselective inhibitor of constitutive NO-synthases.

    PubMed

    Kirichuk, V F; Tsymbal, A A

    2012-02-01

    We studied the effect of terahertz radiation at atmospheric oxygen frequency 129 GHz on blood nitrite concentration in different types of experimental stress against the background of administration of nonselective inhibitor of constitutive NO-synthases. Normalizing effects of radiation on blood nitrite dynamics in animals with acute stress was shown after 15-min exposure and in animals with chronic stress after 30-min exposure. No positive effect of terahertz radiation was observed on altered blood nitrite concentration in male rats after preliminary administration of nonselective constitutive NO-synthase isoform inhibitor L-NAME.

  9. Effects of terahertz radiation at atmospheric oxygen frequency of 129 GHz on blood nitrite concentrations under conditions of different types of stress against the background of administration of nonselective inhibitor of constitutive NO-synthases.

    PubMed

    Kirichuk, V F; Tsymbal, A A

    2012-02-01

    We studied the effect of terahertz radiation at atmospheric oxygen frequency 129 GHz on blood nitrite concentration in different types of experimental stress against the background of administration of nonselective inhibitor of constitutive NO-synthases. Normalizing effects of radiation on blood nitrite dynamics in animals with acute stress was shown after 15-min exposure and in animals with chronic stress after 30-min exposure. No positive effect of terahertz radiation was observed on altered blood nitrite concentration in male rats after preliminary administration of nonselective constitutive NO-synthase isoform inhibitor L-NAME. PMID:22803105

  10. On the determination of the cosmic infrared background radiation from the high-energy spectrum of extragalactic gamma-ray sources

    NASA Technical Reports Server (NTRS)

    Dwek, Eli; Slavin, Jonathan

    1994-01-01

    In a recent paper Stecker, De Jager, & Salamon have suggested using the observed approximately MeV to TeV spectra of extragalactic gamma-ray sources as probes of the local density of the cosmic infrared background radiation (CIBR) and have subsequently claimed a first possible measurement of the CIBR from the analysis of the gamma-ray spectrum of Mrk 421 (De Jager, Stecker, & Salamon). The CIBR from normal galaxies consists of two components: a stellar emission component (CIBRs), and a thermal dust emission component (CIBRd). Photons with energies in the approximately 0.1-2 TeV range interact primarily with the CIBRs, whereas interactions with CIBRd dominate the absorption of photons in the approximately 2-100 TeV energy range. SDS 92 and DSS94 considered only the interaction of the gamma-rays with the dust emission component of the CIBR. We present here an improved analysis of the absorption of extragalactic TeV gamma rays by the CIBR, taking the dual nature of its origin into account. Applying the analysis to the observed gamma-ray spectrum of Mrk 421, a BL Lac object at z = 0.031, we find agreement with DSS94 tentative evidence for absorption by the CINRs. Our analysis therefore limits the detection of the CIBR to the approximately 15-40 micron wavelength regime which, considering the uncertainties in the highest energy (greater than 4 TeV) data and ion the possibility of absorption inside the source, many turn out to be an upper limit on its energy density. At shorter wavelengths (lambda approximately = 1-15 microns), where the gamma-ray interactions are dominated by the CIBRs, our analysis definitely yields only an upper limit on the energy density of the CIBR. In contrast, DSS94 have claimed a possible first measurement of the CIBR over the entire 1-120 micron wavelength region. The upper limit on the CIBRs and tentative detection of the CIBRd are consistent with normal galaxies contributing most of the energy to the CIBR, and constrain the contribution of

  11. Three-dimensional, two-species magnetohydrodynamic studies of the early time behaviors of the Combined Release and Radiation Effects Satellite G2 barium release

    SciTech Connect

    Xie, Lianghai Li, Lei; Wang, Jingdong; Zhang, Yiteng

    2014-04-15

    We present a three-dimensional, two-species (Ba{sup +} and H{sup +}) MHD model to study the early time behaviors of a barium release at about 1 R{sub E} like Combined Release and Radiation Effects Satellite G2, with emphasis placed on the three-dimensional evolution of the barium cloud and its effects on the ambient plasma environment. We find that the perturbations caused by the cloud are the combined results of the initial injection, the radial expansion, and the diamagnetic effect and propagate as fast MHD waves in the magnetosphere. In return, the transverse expansion and the cross-B motion of barium ions are constrained by the magnetic force, which lead to a field-aligned striation of ions and the decoupling of these ions from the neutrals. Our simulation shows the formation and collapse of the diamagnetic cavity in the barium cloud. The estimated time scale for the cavity evolution might be much shorter if photoionization time scale and field aligned expansion of barium ions are considered. In addition, our two species MHD simulation also finds the snowplow effect resulting from the momentum coupling between barium ions and background H{sup +}, which creates density hole and bumps in the background H{sup +} when barium ions expanding along the magnetic field lines.

  12. Cosmological constraints on axionic dark radiation from axion-photon conversion in the early Universe

    SciTech Connect

    Higaki, Tetsutaro; Nakayama, Kazunori; Takahashi, Fuminobu E-mail: kazunori@hep-th.phys.s.u-tokyo.ac.jp

    2013-09-01

    Axions seem ubiquitous in string theories and some of them may be produced non-thermally by heavy scalar decays, contributing to dark radiation. We study various cosmological effects of photons produced from the axionic dark radiation through axion-photon conversion in the presence of primordial magnetic fields, and derive tight constraints on the combination of the axion-photon coupling and the primordial magnetic field.

  13. Voice Quality After Treatment of Early Vocal Cord Cancer: A Randomized Trial Comparing Laser Surgery With Radiation Therapy

    SciTech Connect

    Aaltonen, Leena-Maija; Rautiainen, Noora; Sellman, Jaana; Saarilahti, Kauko; Mäkitie, Antti; Rihkanen, Heikki; Laranne, Jussi; Kleemola, Leenamaija; Wigren, Tuija; Sala, Eeva; Lindholm, Paula; Grenman, Reidar; Joensuu, Heikki

    2014-10-01

    Objective: Early laryngeal cancer is usually treated with either transoral laser surgery or radiation therapy. The quality of voice achieved with these treatments has not been compared in a randomized trial. Methods and Materials: Male patients with carcinoma limited to 1 mobile vocal cord (T1aN0M0) were randomly assigned to receive either laser surgery (n=32) or external beam radiation therapy (n=28). Surgery consisted of tumor excision with a CO{sub 2} laser with the patient under general anaesthesia. External beam radiation therapy to the larynx was delivered to a cumulative dose of 66 Gy in 2-Gy daily fractions over 6.5 weeks. Voice quality was assessed at baseline and 6 and 24 months after treatment. The main outcome measures were expert-rated voice quality on a grade, roughness, breathiness, asthenia, and strain (GRBAS) scale, videolaryngostroboscopic findings, and the patients' self-rated voice quality and its impact on activities of daily living. Results: Overall voice quality between the groups was rated similar, but voice was more breathy and the glottal gap was wider in patients treated with laser surgery than in those who received radiation therapy. Patients treated with radiation therapy reported less hoarseness-related inconvenience in daily living 2 years after treatment. Three patients in each group had local cancer recurrence within 2 years from randomization. Conclusions: Radiation therapy may be the treatment of choice for patients whose requirements for voice quality are demanding. Overall voice quality was similar in both treatment groups, however, indicating a need for careful consideration of patient-related factors in the choice of a treatment option.

  14. Identifying Early Dehydration Risk With Home-Based Sensors During Radiation Treatment: A Feasibility Study on Patients With Head and Neck Cancer

    PubMed Central

    2013-01-01

    Background Systems that enable remote monitoring of patients’ symptoms and other health-related outcomes may optimize cancer care outside of the clinic setting. CYCORE (CYberinfrastructure for COmparative effectiveness REsearch) is a software-based prototype for a user-friendly cyberinfrastructure supporting the comprehensive collection and analyses of data from multiple domains using a suite of home-based and mobile sensors. This study evaluated the feasibility of using CYCORE to address early at-home identification of dehydration risk in head and neck cancer patients undergoing radiation therapy. Methods Head and neck cancer patients used home-based sensors to capture weight, blood pressure, pulse, and patient-reported outcomes for two 5-day periods during radiation therapy. Data were sent to the radiation oncologist of each head and neck cancer patient, who viewed them online via a Web-based interface. Feasibility outcomes included study completion rate, acceptability and perceived usefulness of the intervention, and adherence to the monitoring protocol. We also evaluated whether sensor data could identify dehydration-related events. Results Fifty patients consented to participate, and 48 (96%) completed the study. More than 90% of patients rated their ease, self-efficacy, and satisfaction regarding use of the sensor suite as extremely favorable, with minimal concerns expressed regarding data privacy issues. Patients highly valued the ability to have immediate access to objective, self-monitoring data related to personal risk for dehydration. Clinician assessments indicated a high degree of satisfaction with the ease of using the CYCORE system and the resulting ability to monitor their patients remotely. Conclusion Implementing CYCORE in a clinical oncology care setting is feasible and highly acceptable to both patients and providers. PMID:24395986

  15. Italian news coverage of radiation in the early decades of the twentieth century: A qualitative and quantitative analysis.

    PubMed

    Candela, Andrea; Pasquarè Mariotto, Federico

    2016-02-01

    This work uses a qualitative approach coupled with a quantitative software-based methodology to examine the Italian news media coverage of radiation in the early decades of the twentieth century. We analyze 80 news stories from two of the most influential Italian newspapers from that time: La Stampa (a daily newspaper) and La Domenica del Corriere (an Italian Sunday supplement). While much of previous research on media coverage of scientific topics was generally focused on present-day news, our work revolves around the ground-breaking discovery of X-rays and radioactivity at the dawn of the last century. Our analysis aims to identify journalistic frames in the news coverage of radiation that journalists might have used to emphasize the benefits (or the risks) of the new discoveries. We also hypothesize how this kind of news coverage might have influenced public perception of technological, commercial, and public health applications of the new scientific advancements.

  16. Thermal background noise limitations

    NASA Technical Reports Server (NTRS)

    Gulkis, S.

    1982-01-01

    Modern detection systems are increasingly limited in sensitivity by the background thermal photons which enter the receiving system. Expressions for the fluctuations of detected thermal radiation are derived. Incoherent and heterodyne detection processes are considered. References to the subject of photon detection statistics are given.

  17. How radiation affects superbubbles : Through momentum injection in early phase and photo-heating thereafter

    NASA Astrophysics Data System (ADS)

    Gupta, Siddhartha; Nath, Biman B.; Sharma, Prateek; Shchekinov, Yuri

    2016-08-01

    Energetic winds and radiation from massive star clusters push the surrounding gas and blow superbubbles in the interstellar medium (ISM). Using 1-D hydrodynamic simulations, we study the role of radiation in the dynamics of superbubbles driven by a young star cluster of mass 106 M⊙. We have considered a realistic time evolution of the mechanical power as well as radiation power of the star cluster, and detailed heating and cooling processes. We find that the ratio of the radiation pressure on the shell (shocked ISM) to the thermal pressure (˜107 K) of the shocked wind region is almost independent of the ambient density, and it is greater than unity before ≲ 1 Myr. We explore the parameter space of density and dust opacity of the ambient medium, and find that the size of the hot gas (˜ 107 K) cavity is insensitive to the dust opacity (σd ≈ (0.1 - 1.5) × 10-21 cm2), but the structure of the photoionized (˜104 K) gas depends on it. Most of the radiative losses occur at ˜104 K, with sub-dominant losses at ≲ 103 K and ˜106 - 108 K. The superbubbles can retain as high as ˜10% of its input energy, for an ambient density of 103 mH cm-3. We discuss the role of ionization parameter and recombination-averaged density in understanding the dominant feedback mechanism. Finally, we compare our results with the observations of 30 Doradus.

  18. Response to "Reply to Li, D'angiulli, and Kendall: The Early Development Index and Children from Culturally and Linguistically Diverse Backgrounds" by Janus, Hertzman, Guhn, Brinkman, and Goldfeld

    ERIC Educational Resources Information Center

    Li, Jianghong; D'Angiulli, Amedeo; Kendall, Garth

    2009-01-01

    This article offers a response to "Reply to Li, D'angiulli, and Kendall: The Early Development Index and Children from Culturally and Linguistically Diverse Backgrounds" by Janus, Hertzman, Guhn, Brinkman, and Goldfeld. The authors disagree with Janus et al.'s claim that their paper contained a number of errors and misconceptions. They believe…

  19. Three potato clones incorporating combined resistances to early blight from S. palustre and late blight from S. bulbocastanum into a S. tuberosum background

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three individuals from a segregating population derived from a cross between +297 and K41 are being released as germplasm with resistance to both early blight, caused by Alternaria solani, and late blight, caused by Phytophthora infestans. The source of resistance to early blight from +297 is the wi...

  20. Radiation therapy after breast augmentation or reconstruction in early or recurrent breast cancer

    SciTech Connect

    Ryu, J.; Yahalom, J.; Shank, B.; Chaglassian, T.A.; McCormick, B. )

    1990-09-01

    Fourteen patients whose augmented or reconstructed breasts were treated with radiation therapy were analyzed. Silicone gel implants were used in 13 patients and free-injected silicone in one patient. The total radiation dose ranged from 4400 to 6200 cGy using tangential photon fields or an en face electron field by megavoltage equipment. In several cases, electron boost radiation was added to the tumor bed. The majority of the patients tolerated therapy well with minimal transient skin reactions; only three patients required a treatment break secondary to moist desquamation. Three patients developed documented implant encapsulation, although the majority retained good to excellent cosmesis. In summary, when breast carcinoma arises in the augmented or reconstructed breast, conservative management (i.e., limited surgery and definitive irradiation) is feasible without compromising the therapy or the cosmetic result. Thus, conservative management should be offered as an option to patients who are interested in breast prosthesis conservation.

  1. Radiation Therapy Overcomes Adverse Prognostic Role of Cyclooxygenase-2 Expression on Reed-Sternberg Cells in Early Hodgkin Lymphoma

    SciTech Connect

    Mestre, Francisco; Gutiérrez, Antonio; Rodriguez, Jose; Ramos, Rafael; Garcia, Juan Fernando; Martinez-Serra, Jordi; Casasus, Marta; Nicolau, Cristina; Bento, Leyre; Herraez, Ines; Lopez-Perezagua, Paloma; Daumal, Jaime; Besalduch, Joan

    2015-05-01

    Purpose: To analyze the role of radiation therapy (RT) on the adverse prognostic influence of cyclooxygenase-2 (COX-2) expression on Reed-Sternberg (RS) cells, in the setting of early Hodgkin lymphoma (HL) treated with ABVD (adriamycin, vinblastine, bleomycin, dacarbazine). Methods and Materials: In the present study we retrospectively investigated the prognostic value of COX-2 expression in a large (n=143), uniformly treated early HL population from the Spanish Network of HL using tissue microarrays. Univariate and multivariate analyses were done, including the most recognized clinical variables and the potential role of administration of adjuvant RT. Results: Median age was 31 years; the expression of COX-2 defined a subgroup with significantly worse prognosis. Considering COX-2{sup +} patients, those who received RT had significantly better 5-year progression-free survival (PFS) (80% vs 54% if no RT; P=.008). In contrast, COX-2{sup −} patients only had a modest, nonsignificant benefit from RT in terms of 5-year PFS (90% vs 79%; P=.13). When we compared the outcome of patients receiving RT considering the expression of COX-2 on RS cells, we found a nonsignificant 10% difference in terms of PFS between COX-2{sup +} and COX-2{sup −} patients (P=.09), whereas the difference between the 2 groups was important (25%) in patients not receiving RT (P=.04). Conclusions: Cyclooxygenase-2 RS cell expression is an adverse independent prognostic factor in early HL. Radiation therapy overcomes the worse prognosis associated with COX-2 expression on RS cells, acting in a chemotherapy-independent way. Cyclooxygenase-2 RS cell expression may be useful for determining patient candidates with early HL to receive consolidation with RT.

  2. Ten scenarios from early radiation to late time acceleration with a minimally coupled dark energy

    SciTech Connect

    Fay, Stéphane

    2013-09-01

    We consider General Relativity with matter, radiation and a minimally coupled dark energy defined by an equation of state w. Using dynamical system method, we find the equilibrium points of such a theory assuming an expanding Universe and a positive dark energy density. Two of these points correspond to classical radiation and matter dominated epochs for the Universe. For the other points, dark energy mimics matter, radiation or accelerates Universe expansion. We then look for possible sequences of epochs describing a Universe starting with some radiation dominated epoch(s) (mimicked or not by dark energy), then matter dominated epoch(s) (mimicked or not by dark energy) and ending with an accelerated expansion. We find ten sequences able to follow this Universe history without singular behaviour of w at some saddle points. Most of them are new in dark energy literature. To get more than these ten sequences, w has to be singular at some specific saddle equilibrium points. This is an unusual mathematical property of the equation of state in dark energy literature, whose physical consequences tend to be discarded by observations. This thus distinguishes the ten above sequences from an infinity of ways to describe Universe expansion.

  3. How radiation affects superbubbles: through momentum injection in early phase and photo-heating thereafter

    NASA Astrophysics Data System (ADS)

    Gupta, Siddhartha; Nath, Biman B.; Sharma, Prateek; Shchekinov, Yuri

    2016-11-01

    Energetic winds and radiation from massive star clusters push the surrounding gas and blow superbubbles in the interstellar medium (ISM). Using 1D hydrodynamic simulations, we study the role of radiation in the dynamics of superbubbles driven by a young star cluster of mass 106 M⊙. We have considered a realistic time evolution of the mechanical power as well as radiation power of the star cluster, and detailed heating and cooling processes. We find that the ratio of the radiation pressure on the shell (shocked ISM) to the thermal pressure (˜107 K) of the shocked-wind region is almost independent of the ambient density, and it is greater than unity before ≲1 Myr. We explore the parameter space of density and dust opacity of the ambient medium, and find that the size of the hot gas (˜107 K) cavity is insensitive to the dust opacity [σd ≈ (0.1-1.5) × 10-21 cm2], but the structure of the photoionized (˜104 K) gas depends on it. Most of the radiative losses occur at ˜104 K, with sub-dominant losses at ≲103 K and ˜106-108 K. The superbubbles can retain as high as ˜10 per cent of its input energy, for an ambient density of 103 mH cm-3. We discuss the role of ionization parameter and recombination-averaged density in understanding the dominant feedback mechanism. Finally, we compare our results with the observations of 30 Doradus.

  4. A study of cloud-generated radiative heating and its generation of available potential energy. I - Theoretical background. II - Results for a climatological zonal mean January

    NASA Technical Reports Server (NTRS)

    Stuhlmann, R.; Smith, G. L.

    1988-01-01

    The effect of radiative heating and cooling by clouds on the available potential energy (APE) is theoretically discussed. It is shown that the cloud radiative contribution to the generation of APE is determined by the net cloud radiative heating and the efficiency factor, which is a function of the temperature distribution of the atmosphere. Results are presented for low and middle cloud effects for three atmospheric layers. Cloud radiative heating is found to be a single function of cloud optical thickness for all classes designed in terms of cloud top heights and optical thickness. Low clouds at low latitudes destroy APE an midclouds generate APE. A concept is developed to relate the cloud radiative heating to cloud heights and optical depths. Cloud-generated radiative heating is computed for January zonal mean conditions for low and midclouds. For both cases, the strongest influence is found in the low troposphere, with marked differences in signs and magnitudes. At extratropical latitudes, both cloud classes generate net radiative cooling. In the tropics, the effect of low cloud changes from net cooling to the net heating as the optical thickness increases, and midclouds cause net heating. A mechanism is described whereby this dependence produces a strong positive feedback effect on the development of SST anomalies in the tropical oceans.

  5. Radiation

    NASA Video Gallery

    Outside the protective cocoon of Earth's atmosphere, the universe is full of harmful radiation. Astronauts who live and work in space are exposed not only to ultraviolet rays but also to space radi...

  6. The genetic basis of strain-dependent differences in the early phase of radiation injury in mouse lung

    SciTech Connect

    Franko, A.J.; Sharplin, J.; Ward, W.F.; Hinz, J.M. )

    1991-06-01

    Substantial differences between mouse strains have been reported in the lesions present in the lung during the early phase of radiation injury. Some strains show only classical pneumonitis, while other strains develop substantial fibrosis and hyaline membranes which contribute appreciably to respiratory insufficiency, in addition to pneumonitis. Other strains are intermediate between these extremes. These differences correlate with intrinsic differences in activities of lung plasminogen activator and angiotensin converting enzyme. The genetic basis of these differences was assessed by examining histologically the early reaction in lungs of seven murine hybrids available commercially after whole-thorax irradiation. Crosses between fibrosing and nonfibrosing parents were uniformly nonfibrosing, and crosses between fibrosing and intermediate parents were uniformly intermediate. No evidence of sex linkage was seen. Thus the phenotype in which fibrosis is found is controlled by autosomal recessive determinants. Strains prone to radiation-induced pulmonary fibrosis and hyaline membranes exhibited intrinsically lower activities of lung plasminogen activator and angiotensin converting enzyme than either the nonfibrosing strains or the nonfibrosing hybrid crosses. The median time of death of the hybrids was genetically determined primarily by the longest-lived parent regardless of the types of lesions expressed.

  7. Cosmetic Outcome and Seroma Formation After Breast-Conserving Surgery With Intraoperative Radiation Therapy Boost for Early Breast Cancer

    SciTech Connect

    Senthi, Sashendra; Link, Emma; Chua, Boon H.

    2012-10-01

    Purpose: To evaluate cosmetic outcome and its association with breast wound seroma after breast-conserving surgery (BCS) with targeted intraoperative radiation therapy (tIORT) boost for early breast cancer. Methods and Materials: An analysis of a single-arm prospective study of 55 patients with early breast cancer treated with BCS and tIORT boost followed by conventional whole breast radiation therapy (WBRT) between August 2003 and January 2006 was performed. A seroma was defined as a fluid collection at the primary tumor resection site identified clinically or radiologically. Cosmetic assessments using the European Organization for Research and Treatment of Cancer rating system were performed at baseline before BCS and 30 months after WBRT was completed. Results: Twenty-eight patients (51%) developed a seroma, with 18 patients (33%) requiring at least 1 aspiration. Tumor location was significantly associated with seroma formation (P=.001). Ten of 11 patients with an upper inner quadrant tumor developed a seroma. Excellent or good overall cosmetic outcome at 30 months was observed in 34 patients (62%, 95% confidence interval 53%-80%). Seroma formation was not associated with the overall cosmetic result (P=.54). Conclusion: BCS with tIORT boost followed by WBRT was associated with an acceptable cosmetic outcome. Seroma formation was not significantly associated with an adverse cosmetic outcome.

  8. Amelioration of both early and late radiation-induced damage to pig skin by essential fatty acids

    SciTech Connect

    Hopewell, J.W.; Van den Aardweg, G.J.M.J.; Morris, G.M.

    1994-12-01

    To evaluate the possible role of essential fatty acids, specifically gamma-linolenic and eicosapentaenoic acid, in the amelioration of early and late radiation damage to the skin. Skin sites on the flank of 22-25 kg female large white pigs were irradiated with either single or fractionated doses (20 F/28 days) of {beta}-rays from 22.5 mm diameter {sup 90}Sr/{sup 90}Y plaques at a dose rate of {approximately}3 Gy/min. Essential fatty acids were administered orally in the form of two {open_quotes}active{close_quotes} oils, So-1100 and So-5407, which contained gamma-linolenic acid and a mixture of that oil with eicosapentaenoic acid, respectively. Oils (1.5-6.0 ml) were given daily for 4 weeks prior, both 4 weeks prior and 10-16 weeks after, or in the case of one single dose study, just for 10 weeks after irradiation. Control animals received a {open_quotes}placebo{close_quotes} oil, So-1129, containing no gamma linolenic acid or eicosapentaenoic acid over similar time scales before and after irradiation. Acute and late skin reactions were assessed visually and the dose-related incidence of a specific reaction used to compare the effects of different treatment schedules. A reduction in the severity of both the early and late radiation reactions in the skin was only observed when {open_quotes}active{close_quotes} oils were given over the time course of the expression of radiation damage. Prior treatment with oils did not modify the radiation reaction. A 3.0 ml daily dose of either So-1100 or So-5407 given prior to, but also after irradiation with single and fractionated doses of {beta}-rays produced the most significant modification to the radiation reactions, effects consistent with dose modification factors between 1.06-1.24 for the acute reactions of bright red erythema and/or moist desquamation, and of 1.14-1.35 for the late reactions of dusky/mauve erythema and dermal necrosis. 38 refs., 5 tabs.

  9. Early life exposure to diagnostic radiation and ultrasound scans and risk of childhood cancer: case-control study

    PubMed Central

    Simpson, Jill; Neta, Gila; Berrington de Gonzalez, Amy; Ansell, Pat; Linet, Martha S; Ron, Elaine; Roman, Eve

    2011-01-01

    Objective To examine childhood cancer risks associated with exposure to diagnostic radiation and ultrasound scans in utero and in early infancy (age 0-100 days). Design Case-control study. Setting England and Wales. Participants 2690 childhood cancer cases and 4858 age, sex, and region matched controls from the United Kingdom Childhood Cancer Study (UKCCS), born 1976-96. Main outcome measures Risk of all childhood cancer, leukaemia, lymphoma, and central nervous system tumours, measured by odds ratios. Results Logistic regression models conditioned on matching factors, with adjustment for maternal age and child’s birth weight, showed no evidence of increased risk of childhood cancer with in utero exposure to ultrasound scans. Some indication existed of a slight increase in risk after in utero exposure to x rays for all cancers (odds ratio 1.l4, 95% confidence interval 0.90 to 1.45) and leukaemia (1.36, 0.91 to 2.02), but this was not statistically significant. Exposure to diagnostic x rays in early infancy (0-100 days) was associated with small, non-significant excess risks for all cancers and leukaemia, as well as increased risk of lymphoma (odds ratio 5.14, 1.27 to 20.78) on the basis of small numbers. Conclusions Although the results for lymphoma need to be replicated, all of the findings indicate possible risks of cancer from radiation at doses lower than those associated with commonly used procedures such as computed tomography scans, suggesting the need for cautious use of diagnostic radiation imaging procedures to the abdomen/pelvis of the mother during pregnancy and in children at very young ages. PMID:21310791

  10. [Development of radioadaptive properties for microscopic fungi, long time located on terrains with a heightened background radiation after emergency on Chernobyl NPP].

    PubMed

    Tugaĭ, T I; Zhdanova, N N; Zheltonozhskiĭ, V A; Sadovnikov, L V

    2007-01-01

    In 7 species of micromycetes which were isolated from radioactive contaminated areas of Chernobyl NPP zone under exposure of two artificial sources: y-low energy (121Sn) and radiation mix type gamma + beta (137Cs). Two new earlier unknown radioadaptive properties for fungi--radiotropism and radiostimulation were established. The strains, which were isolated from clean areas, did not have such features. All investigated strains, which have shown positive radiotropism at the same time, have shown stimulation of conidia germination and of length of the emergent hyphum under exposure to one of sources of radiation. It was shown that micro fungi having radioadaptive properties, the adaptive response to high (100-1000 Gy) ionizing radiation doses was found that is evidence of that these strains have high radio resistance level. Nevertheless fungal strains have shown varied response to presence of ionizing radiation depending on its type and absorbed dose.

  11. Van Allen Probes: Successful launch campaign and early operations exploring Earth's radiation belts

    NASA Astrophysics Data System (ADS)

    Kirby, K.; Stratton, J.

    The twin Van Allen Probe observatories developed at The Johns Hopkins University Applied Physics Laboratory for NASA's Heliophysics Division completed final observatory integration and environmental test activities and were successfully launched into orbit around the Earth on August 30, 2012. As the science operations phase begins, the mission is providing exciting new information about the impact of radiation belt activity on the earth. The on-board boom mounted magnetometers and other instruments are the most sensitive sensors of their type that have ever flown in the Van Allen radiation belts. The observatories are producing near-Earth space weather information that can be used to provide warnings of potential power grid interruptions or satellite damaging storms. The Van Allen Probes are operating in a challenging high radiation environment, and at the same time they are designed to make an insubstantial electric and magnetic field contribution to their surroundings. This paper will describe the challenges associated with observatory integration and test activities and observatory on-orbit checkout and commissioning. The lessons learned can be applied to other observatories and payloads that will be exposed to similar environments.

  12. Radiative shocks and nonequilibrium chemistry in the early universe - Galaxy and primordial star formation

    NASA Technical Reports Server (NTRS)

    Shapiro, Paul R.; Kang, Hyesung

    1990-01-01

    The nonequilibrium radiative cooling, recombination, and molecule formation behind steady-state shock waves in primordial composition gas is studied. The hydrodynamical conservation equations are solved as well as equations for nonequilibrium ionization, recombination, and molecule formation and the equation of radiative transfer. The shocked gas is found to cool faster than it can recombine; as a result it is able to form an H2 concentration as high as 0.001 or higher via the formation of H(-) and H2(+) intermediaries due to the enhanced nonequilibrium ionization at 10,000 K. With such an H2 concentration, the gas cools by rotational-vibrational line excitation of H2 molecules to well below the canonical final temperature of 10,000 K for a molecule-free gas without metals. It is shown that, as the level of external ionizing and dissociating radiation flux is increased, the formation of and cooling by H2 molecules can be inhibited and delayed.

  13. Spectral distortions of the cosmic microwave background

    NASA Technical Reports Server (NTRS)

    Adams, Fred C.; Mcdowell, Jonathan C.; Freese, Katherine; Levin, Janna

    1989-01-01

    Recent experiments indicate that the spectrum of the cosmic microwave background deviates from a pure blackbody; here, spectral distortions produced by cosmic dust are considered. The main result is that cosmic dust in conjunction with an injected radiation field (perhaps produced by an early generation of very massive stars) can explain the observed spectral distortions without violating existing cosmological constraints. In addition, it is shown that Compton y-distortions can also explain the observed spectral shape, but the energetic requirements are more severe.

  14. Singular F(R) cosmology unifying early- and late-time acceleration with matter and radiation domination era

    NASA Astrophysics Data System (ADS)

    Odintsov, S. D.; Oikonomou, V. K.

    2016-06-01

    We present some cosmological models which unify the late- and early-time acceleration eras with the radiation and the matter domination era, and we realize the cosmological models by using the theoretical framework of F(R) gravity. Particularly, the first model unifies the late- and early-time acceleration with the matter domination era, and the second model unifies all the evolution eras of our Universe. The two models are described in the same way at early and late times, and only the intermediate stages of the evolution have some differences. Each cosmological model contains two Type IV singularities which are chosen to occur one at the end of the inflationary era and one at the end of the matter domination era. The cosmological models at early times are approximately identical to the R 2 inflation model, so these describe a slow-roll inflationary era which ends when the slow-roll parameters become of order one. The inflationary era is followed by the radiation era and after that the matter domination era follows, which lasts until the second Type IV singularity, and then the late-time acceleration era follows. The models have two appealing features: firstly they produce a nearly scale invariant power spectrum of primordial curvature perturbations and a scalar-to-tensor ratio which are compatible with the most recent observational data and secondly, it seems that the deceleration–acceleration transition is crucially affected by the presence of the second Type IV singularity which occurs at the end of the matter domination era. As we demonstrate, the Hubble horizon at early times shrinks, as expected for an initially accelerating Universe, then during the matter domination era, it expands and finally after the Type IV singularity, the Hubble horizon starts to shrink again, during the late-time acceleration era. Intriguingly enough, the deceleration–acceleration transition, occurs after the second Type IV singularity. In addition, we investigate which F

  15. Singular F(R) cosmology unifying early- and late-time acceleration with matter and radiation domination era

    NASA Astrophysics Data System (ADS)

    Odintsov, S. D.; Oikonomou, V. K.

    2016-06-01

    We present some cosmological models which unify the late- and early-time acceleration eras with the radiation and the matter domination era, and we realize the cosmological models by using the theoretical framework of F(R) gravity. Particularly, the first model unifies the late- and early-time acceleration with the matter domination era, and the second model unifies all the evolution eras of our Universe. The two models are described in the same way at early and late times, and only the intermediate stages of the evolution have some differences. Each cosmological model contains two Type IV singularities which are chosen to occur one at the end of the inflationary era and one at the end of the matter domination era. The cosmological models at early times are approximately identical to the R 2 inflation model, so these describe a slow-roll inflationary era which ends when the slow-roll parameters become of order one. The inflationary era is followed by the radiation era and after that the matter domination era follows, which lasts until the second Type IV singularity, and then the late-time acceleration era follows. The models have two appealing features: firstly they produce a nearly scale invariant power spectrum of primordial curvature perturbations and a scalar-to-tensor ratio which are compatible with the most recent observational data and secondly, it seems that the deceleration-acceleration transition is crucially affected by the presence of the second Type IV singularity which occurs at the end of the matter domination era. As we demonstrate, the Hubble horizon at early times shrinks, as expected for an initially accelerating Universe, then during the matter domination era, it expands and finally after the Type IV singularity, the Hubble horizon starts to shrink again, during the late-time acceleration era. Intriguingly enough, the deceleration-acceleration transition, occurs after the second Type IV singularity. In addition, we investigate which F(R) gravity

  16. In vivo characterization of early-stage radiation skin injury in a mouse model by two-photon microscopy

    PubMed Central

    Jang, Won Hyuk; Shim, Sehwan; Wang, Taejun; Yoon, Yeoreum; Jang, Won-Suk; Myung, Jae Kyung; Park, Sunhoo; Kim, Ki Hean

    2016-01-01

    Ionizing radiation (IR) injury is tissue damage caused by high energy electromagnetic waves such as X-ray and gamma ray. Diagnosis and treatment of IR injury are difficult due to its characteristics of clinically latent post-irradiation periods and the following successive and unpredictable inflammatory bursts. Skin is one of the many sensitive organs to IR and bears local injury upon exposure. Early-stage diagnosis of IR skin injury is essential in order to maximize treatment efficiency and to prevent the aggravation of IR injury. In this study, early-stage changes of the IR injured skin at the cellular level were characterized in an in vivo mouse model by two-photon microscopy (TPM). Various IR doses were applied to the mouse hind limbs and the injured skin regions were imaged daily for 6 days after IR irradiation. Changes in the morphology and distribution of the epidermal cells and damage of the sebaceous glands were observed before clinical symptoms. These results showed that TPM is sensitive to early-stage changes of IR skin injury and may be useful for its diagnosis. PMID:26755422

  17. In vivo characterization of early-stage radiation skin injury in a mouse model by two-photon microscopy.

    PubMed

    Jang, Won Hyuk; Shim, Sehwan; Wang, Taejun; Yoon, Yeoreum; Jang, Won-Suk; Myung, Jae Kyung; Park, Sunhoo; Kim, Ki Hean

    2016-01-01

    Ionizing radiation (IR) injury is tissue damage caused by high energy electromagnetic waves such as X-ray and gamma ray. Diagnosis and treatment of IR injury are difficult due to its characteristics of clinically latent post-irradiation periods and the following successive and unpredictable inflammatory bursts. Skin is one of the many sensitive organs to IR and bears local injury upon exposure. Early-stage diagnosis of IR skin injury is essential in order to maximize treatment efficiency and to prevent the aggravation of IR injury. In this study, early-stage changes of the IR injured skin at the cellular level were characterized in an in vivo mouse model by two-photon microscopy (TPM). Various IR doses were applied to the mouse hind limbs and the injured skin regions were imaged daily for 6 days after IR irradiation. Changes in the morphology and distribution of the epidermal cells and damage of the sebaceous glands were observed before clinical symptoms. These results showed that TPM is sensitive to early-stage changes of IR skin injury and may be useful for its diagnosis. PMID:26755422

  18. The GLAST Background Model

    SciTech Connect

    Ormes, J.F.; Atwood, W.; Burnett, T.; Grove, E.; Longo, F.; McEnery, J.; Mizuno, T.; Ritz, S.; /NASA, Goddard

    2007-10-17

    In order to estimate the ability of the GLAST/LAT to reject unwanted background of charged particles, optimize the on-board processing, size the required telemetry and optimize the GLAST orbit, we developed a detailed model of the background particles that would affect the LAT. In addition to the well-known components of the cosmic radiation, we included splash and reentrant components of protons, electrons (e+ and e-) from 10 MeV and beyond as well as the albedo gamma rays produced by cosmic ray interactions with the atmosphere. We made estimates of the irreducible background components produced by positrons and hadrons interacting in the multilayered micrometeorite shield and spacecraft surrounding the LAT and note that because the orbital debris has increased, the shielding required and hence the background are larger than were present in EGRET. Improvements to the model are currently being made to include the east-west effect.

  19. Computed Tomography Appearance of Early Radiation Injury to the Lung: Correlation With Clinical and Dosimetric Factors

    SciTech Connect

    Jenkins, Peter; Welsh, Anne

    2011-09-01

    Purpose: To systematically assess the spectrum of radiologic changes in the lung after radiation therapy for non-small-cell lung cancer. Methods and Materials: We reviewed the cases of 146 patients treated with radical radiotherapy at our institution. All patients had computed tomography (CT) scans performed 3 months after completion of therapy. Radiographic appearances were categorized using a standard grading system. The association of these abnormalities with pretreatment factors and clinical radiation pneumonitis (RP) was investigated. Results: New intrapulmonary abnormalities were seen in 92 patients (63%). These were ground-glass opacity in 16 (11%), patchy consolidation in 19 (13%), and diffuse consolidation in 57 (39%). Twenty-five patients (17%) developed clinical symptoms of RP. Although 80% of the patients with RP had areas of consolidation seen on the posttreatment CT scan, the majority (74%) of patients with such radiographic changes were asymptomatic. For patients with lung infiltrates, the minimum isodose encompassing the volume of radiologic abnormality was usually {>=}27 Gy. Traditional dose-volume metrics, pulmonary function tests, and the coadministration of angiotensin converting enzyme inhibitors (ACE-I) were all strongly correlated with the presence of radiologic injury on univariate analysis (p {<=} 0.002). There was also an inverse correlation between prior smoking history and CT scan changes (p = 0.02). On multivariate analysis, dosimetric parameters and the use of ACE-I retained significance (p = 0.005). Conclusions: Our findings suggest that there is substantial interindividual variation in lung radiosensitivity. ACE-I prevented the radiologic changes seen after high-dose radiation therapy, and their role as radioprotectants warrants further investigation.

  20. Investigating the Impact of Early Institutional Deprivation on Development: Background and Research Strategy of the English and Romanian Adoptees (ERA) Study

    ERIC Educational Resources Information Center

    Rutter, Michael; Sonuga-Barke, Edmund J.; Castle, Jennifer

    2010-01-01

    This monograph is concerned with the mid adolescent follow-up of a group of adoptees from Romania and from within the United Kingdom who were first assessed at the age of 4 years (or 6 years in the case of the oldest children). After describing the structure of this monograph, this chapter provides the background as it applied at the time that the…

  1. Joseph John Thomson's models of matter and radiation in the early 1890s.

    PubMed

    Bordoni, Stefano

    In the late nineteenth century, Joseph John Thomson moved away from Maxwell's specific theoretical models of matter and energy, even though he continued to rely on the general framework of Maxwell's electromagnetic theory. In his 1893 book, he accomplished the conceptual drift towards a discrete model for matter, electricity, and fields. In Thomson's model, energy was linked to tubes of force, in particular to the aether contained in them and surrounding them: the energy was the kinetic energy of aether, of both a rotational and translational kind. Starting from Maxwell's electromagnetic fields, namely stresses propagating through a continuous solid medium, Thomson arrived at a representation of fields as a sea of discrete units carrying energy and momentum. He tried to transform Maxwell's theory into a unified picture in which atomic models of matter stood beside atomic models of fields. In 1904 his interpretation of X-rays was based on the integration between two complementary features of electromagnetic radiation, the continuity and the discreteness, and on some kind of fibrous aether. In recent secondary literature, the problematic conceptual link between J. J. Thomson's theory and contemporary theories on electromagnetic radiation has been underestimated. On the contrary, in the first half of the twentieth century, some physicists inquired into that link, and a widespread debate emerged, misunderstandings included.

  2. The cosmic microwave background

    NASA Technical Reports Server (NTRS)

    Silk, Joseph

    1989-01-01

    Recent observational and theoretical investigations of the cosmic microwave background radiation (CMBR) are reviewed. Particular attention is given to spectral distortions and CMBR temperature anisotropies at large, intermediate, and small angular scales. The implications of the observations for inflationary cosmological models with curvature fluctuation are explored, and it is shown that the limits determined for intermediate-scale CMBR anisotropy almost rule out a baryon-dominated cosmology.

  3. Early to mid Cretaceous vegetation of northern Gondwana - the onset of angiosperm radiation and climatic implications

    NASA Astrophysics Data System (ADS)

    Coiffard, Clément; Mohr, Barbara

    2014-05-01

    Early Cretaceous Northern Gondwana seems to be the cradle of many early flowering plants, especially mesangiosperms that include magnoliids and monocots and basal eudicots. So far our knowledge was based mostly on dispersed pollen and small flowering structures. New fossil finds from Brazil include more complete plants with attached roots, leaves and flowers. Taxonomic studies show that these fossils belonged to clades which are, based on macroscopic characters and molecular data, also considered to be rather basal, such as several members of Nymphaeales, Piperales, Laurales, Magnoliales, monocots (Araliaceae) and Ranunculales. Various parameters can be used in order to understand the physiology and habitat of these plants. Adaptations to climate and habitat are partly mirrored in their root anatomy (evidence of tap roots), leaf size and shape, leaf anatomy including presence of glands, and distribution of stomata. An important ecophysiolocical parameter is vein density as an indicator for the plants' cabability to pump water, and the stomatal pore index, representing the proportion of stomatal pore area on the leaf surface, which is related to the water vapor resistance of the leaf epidermis. During the mid-Cretaceous leaf vein density started to surpass that of gymnosperms, one factor that made angiosperms very successful in conquering many kinds of new environments. Using data on these parameters we deduce that during the late Early to mid Cretaceous angiosperms were already diverse, being represented as both herbs, with aquatic members, such as Nymphaeles, helophytes (e.g. some monocots) and plants that may have grown in shady locations. Other life forms included shrubs and perhaps already small trees (e.g. Magnoliales). These flowering plants occupied various habitats, ranging from xeric (e.g. some Magnoliales) to mesic and shady (e.g. Piperales) or aquatic (e.g. Araceae, Nymphaeales). Overall, it seems that several of these plants clearly exhibited some

  4. A total-evidence approach to dating with fossils, applied to the early radiation of the hymenoptera.

    PubMed

    Ronquist, Fredrik; Klopfstein, Seraina; Vilhelmsen, Lars; Schulmeister, Susanne; Murray, Debra L; Rasnitsyn, Alexandr P

    2012-12-01

    Phylogenies are usually dated by calibrating interior nodes against the fossil record. This relies on indirect methods that, in the worst case, misrepresent the fossil information. Here, we contrast such node dating with an approach that includes fossils along with the extant taxa in a Bayesian total-evidence analysis. As a test case, we focus on the early radiation of the Hymenoptera, mostly documented by poorly preserved impression fossils that are difficult to place phylogenetically. Specifically, we compare node dating using nine calibration points derived from the fossil record with total-evidence dating based on 343 morphological characters scored for 45 fossil (4--20 complete) and 68 extant taxa. In both cases we use molecular data from seven markers (∼5 kb) for the extant taxa. Because it is difficult to model speciation, extinction, sampling, and fossil preservation realistically, we develop a simple uniform prior for clock trees with fossils, and we use relaxed clock models to accommodate rate variation across the tree. Despite considerable uncertainty in the placement of most fossils, we find that they contribute significantly to the estimation of divergence times in the total-evidence analysis. In particular, the posterior distributions on divergence times are less sensitive to prior assumptions and tend to be more precise than in node dating. The total-evidence analysis also shows that four of the seven Hymenoptera calibration points used in node dating are likely to be based on erroneous or doubtful assumptions about the fossil placement. With respect to the early radiation of Hymenoptera, our results suggest that the crown group dates back to the Carboniferous, ∼309 Ma (95% interval: 291--347 Ma), and diversified into major extant lineages much earlier than previously thought, well before the Triassic. [Bayesian inference; fossil dating; morphological evolution; relaxed clock; statistical phylogenetics.].

  5. A Total-Evidence Approach to Dating with Fossils, Applied to the Early Radiation of the Hymenoptera

    PubMed Central

    Ronquist, Fredrik; Klopfstein, Seraina; Vilhelmsen, Lars; Schulmeister, Susanne; Murray, Debra L.; Rasnitsyn, Alexandr P.

    2012-01-01

    Phylogenies are usually dated by calibrating interior nodes against the fossil record. This relies on indirect methods that, in the worst case, misrepresent the fossil information. Here, we contrast such node dating with an approach that includes fossils along with the extant taxa in a Bayesian total-evidence analysis. As a test case, we focus on the early radiation of the Hymenoptera, mostly documented by poorly preserved impression fossils that are difficult to place phylogenetically. Specifically, we compare node dating using nine calibration points derived from the fossil record with total-evidence dating based on 343 morphological characters scored for 45 fossil (4--20 complete) and 68 extant taxa. In both cases we use molecular data from seven markers (∼5 kb) for the extant taxa. Because it is difficult to model speciation, extinction, sampling, and fossil preservation realistically, we develop a simple uniform prior for clock trees with fossils, and we use relaxed clock models to accommodate rate variation across the tree. Despite considerable uncertainty in the placement of most fossils, we find that they contribute significantly to the estimation of divergence times in the total-evidence analysis. In particular, the posterior distributions on divergence times are less sensitive to prior assumptions and tend to be more precise than in node dating. The total-evidence analysis also shows that four of the seven Hymenoptera calibration points used in node dating are likely to be based on erroneous or doubtful assumptions about the fossil placement. With respect to the early radiation of Hymenoptera, our results suggest that the crown group dates back to the Carboniferous, ∼309 Ma (95% interval: 291--347 Ma), and diversified into major extant lineages much earlier than previously thought, well before the Triassic. [Bayesian inference; fossil dating; morphological evolution; relaxed clock; statistical phylogenetics.] PMID:22723471

  6. Morphological and transcriptional response of an anhydrobiotic insect to ionizing radiation and desiccation: steps forward in understanding molecular background of extreme radioresistance in higher eukaryotes

    NASA Astrophysics Data System (ADS)

    Gusev, Oleg; Novikova, Nataliya; Sychev, Vladimir; Okuda, Takashi; Kikawada, Takahiro; Sakashita, Tetsuya; Mukae, Kyosuke

    2012-07-01

    Life in extreme or drastically changing environments in many cases leads to evolutionary evolvement of mechanisms of cross-resistance to different abiotic stresses, often never actually faced by the organism in its natural habitat. Larvae of the sleeping chironomidPolypedilum vanderplanki (Diptera) are able to resist complete desiccation and in the dry form survive under excess of various abiotic stresses, including exposure to space environment. One of the most intriguing features of the anhydrobiotic larvae is resistance to extremely high doses of different types of ionizing radiation. To understand the cross-tolerance mechanism, we have analyzed the structural changes in the nuclear DNA using transmission electron microscopy and DNA comet assays in relation to anhydrobiosis and radiation. We find that dehydration causes alterations in chromatin structure and a severe fragmentation of nuclear DNA in the cells of the larvae despite successful anhydrobiosis. The DNA fragmentation level and the recovery of DNA integrity in the rehydrated after anhydrobiosis larvae were similar to those of hydrated larvae irradiated with 70 Gy of high-linear energy transfer (LET) ions (4He+). In comparison, low-LET radiation (gamma rays) of the same dose causes less initial damage to the larvae, and recovery of DNA repair is complete within 24 h. Genome-wide analysis of mRNA expression in the larvae revealed that a large group of genes (including antioxidants, anhydrobiosis-specific biomolecules and protein-reparation enzymes) showed a similar patterns of activity in response to both desiccation and ionizing radiation. We conclude that t one of the factors explaining the relationship between the resistance to ionizing radiation and the ability to undergo anhydrobiosis in the sleeping chironomid would be an adaptation to desiccation-inflicted proteins and nuclear DNA damage.

  7. Explosive radiation or uninformative genes? Origin and early diversification of tachinid flies (Diptera: Tachinidae).

    PubMed

    Winkler, Isaac S; Blaschke, Jeremy D; Davis, Daniel J; Stireman, John O; O'Hara, James E; Cerretti, Pierfilippo; Moulton, John K

    2015-07-01

    Molecular phylogenetic studies at all taxonomic levels often infer rapid radiation events based on short, poorly resolved internodes. While such rapid episodes of diversification are an important and widespread evolutionary phenomenon, much of this poor phylogenetic resolution may be attributed to the continuing widespread use of "traditional" markers (mitochondrial, ribosomal, and some nuclear protein-coding genes) that are often poorly suited to resolve difficult, higher-level phylogenetic problems. Here we reconstruct phylogenetic relationships among a representative set of taxa of the parasitoid fly family Tachinidae and related outgroups of the superfamily Oestroidea. The Tachinidae are one of the most species rich, yet evolutionarily recent families of Diptera, providing an ideal case study for examining the differential performance of loci in resolving phylogenetic relationships and the benefits of adding more loci to phylogenetic analyses. We assess the phylogenetic utility of nine genes including both traditional genes (e.g., CO1 mtDNA, 28S rDNA) and nuclear protein-coding genes newly developed for phylogenetic analysis. Our phylogenetic findings, based on a limited set of taxa, include: a close relationship between Tachinidae and the calliphorid subfamily Polleninae, monophyly of Tachinidae and the subfamilies Exoristinae and Dexiinae, subfamily groupings of Dexiinae+Phasiinae and Tachininae+Exoristinae, and robust phylogenetic placement of the somewhat enigmatic genera Strongygaster, Euthera, and Ceracia. In contrast to poor resolution and phylogenetic incongruence of "traditional genes," we find that a more selective set of highly informative genes is able to more precisely identify regions of the phylogeny that experienced rapid radiation of lineages, while more accurately depicting their phylogenetic context. Although much expanded taxon sampling is necessary to effectively assess the monophyly of and relationships among major tachinid lineages and

  8. Explosive radiation or uninformative genes? Origin and early diversification of tachinid flies (Diptera: Tachinidae).

    PubMed

    Winkler, Isaac S; Blaschke, Jeremy D; Davis, Daniel J; Stireman, John O; O'Hara, James E; Cerretti, Pierfilippo; Moulton, John K

    2015-07-01

    Molecular phylogenetic studies at all taxonomic levels often infer rapid radiation events based on short, poorly resolved internodes. While such rapid episodes of diversification are an important and widespread evolutionary phenomenon, much of this poor phylogenetic resolution may be attributed to the continuing widespread use of "traditional" markers (mitochondrial, ribosomal, and some nuclear protein-coding genes) that are often poorly suited to resolve difficult, higher-level phylogenetic problems. Here we reconstruct phylogenetic relationships among a representative set of taxa of the parasitoid fly family Tachinidae and related outgroups of the superfamily Oestroidea. The Tachinidae are one of the most species rich, yet evolutionarily recent families of Diptera, providing an ideal case study for examining the differential performance of loci in resolving phylogenetic relationships and the benefits of adding more loci to phylogenetic analyses. We assess the phylogenetic utility of nine genes including both traditional genes (e.g., CO1 mtDNA, 28S rDNA) and nuclear protein-coding genes newly developed for phylogenetic analysis. Our phylogenetic findings, based on a limited set of taxa, include: a close relationship between Tachinidae and the calliphorid subfamily Polleninae, monophyly of Tachinidae and the subfamilies Exoristinae and Dexiinae, subfamily groupings of Dexiinae+Phasiinae and Tachininae+Exoristinae, and robust phylogenetic placement of the somewhat enigmatic genera Strongygaster, Euthera, and Ceracia. In contrast to poor resolution and phylogenetic incongruence of "traditional genes," we find that a more selective set of highly informative genes is able to more precisely identify regions of the phylogeny that experienced rapid radiation of lineages, while more accurately depicting their phylogenetic context. Although much expanded taxon sampling is necessary to effectively assess the monophyly of and relationships among major tachinid lineages and

  9. [Early-onset radiation complications and tissue damage in the treatment of head and neck tumors].

    PubMed

    Isaev, P A; Medvedev, V S; Pasov, V V; Semin, D Iu; Derbugov, D N; Pol'kin, V V; Terekhov, O V

    2010-01-01

    The report discusses the results of an evaluation of the effectiveness of combined radiotherapy in 1,192 cases of head and neck tumors divided into 4 groups: distant radiotherapy in standard fractions of 1.8-2.3 Gy, 5 times a week, TTD of 60 Gy (group 1 - 486 40.8%); radiotherapy + local UHF hyperthermia + regional intraarterial chemotherapy + hyper glycemia + administrations of regional intraarterial chemotherapy + hyperglycemia + local UHF hyperthermia (group 2 - 244 20.5%); accelerated superfractition radiotherapy with variable STD of 1 and 1.5/2 Gy, TTD of 60 Gy, plus neoadjuvant polychemotherapy with cisplatin 100 mg/lm2 + 5-fluorouracil, continuous intravenous infusion of 3,000 mg for 72 h (group 3 - 204 17%1); combined photon-neutron therapy (group 4 - 258 21.6%): neutron beam therapy - 36 (3%); interstitial neutron brachytherapy with 252 Cf sources in combination with external beam gamma-therapy and chemotherapy. Overall radiation injury incidence was 1,087 (91.2%); oral mucositis grade I (WHO) - 110 (9.2%), grade II - 166(13.9%), grade III - 811 (68%), radiation dermatitis - 279 (23.4%), grade I/II - 196 (16.4%), grade III/IV - 83 (7%). Grade III/IV side effects developed in 26.7% after gamma therapy and in 72.2% - in the photon-neutron group (p < or = 0.0001). Skin damage was rare, as expected, in the photon-brachytherapy group (1.8%) (p < or = 0.0001). Hence, Cf252 neutron brachytherapy and radiotherapy with concomitant chemotherapy appeared to produce the most sparing effects. PMID:21137234

  10. At the feet of the dinosaurs: the early history and radiation of lizards.

    PubMed

    Evans, Susan E

    2003-11-01

    Lizards, snakes and amphisbaenians together constitute the Squamata, the largest and most diverse group of living reptiles. Despite their current success, the early squamate fossil record is extremely patchy. The last major survey of squamate palaeontology and evolution was published 20 years ago. Since then, there have been major changes in systematic theory and methodology, as well as a steady trickle of new fossil finds. This review examines our current understanding of the first 150 million years of squamate evolution in the light of the new data and changing ideas. Contrary to previous reports, no squamate fossils are currently documented before the Jurassic. Nonetheless, indirect evidence predicts that squamates had evolved by at least the middle Triassic, and had diversified into existing major lineages before the end of this period. There is thus a major gap in the squamate record at a time when key morphological features were evolving. With the exception of fragmentary remains from Africa and India, Jurassic squamates are known only from localities in northern continents (Laurasia). The situation improves in the Early Cretaceous, but the southern (Gondwanan) record remains extremely poor. This constrains palaeobiogeographic discussion and makes it difficult to predict centres of origin for major squamate clades on the basis of fossil evidence alone. Preliminary mapping of morphological characters onto a consensus tree demonstrates stages in the sequence of acquisition for some characters of the skull and postcranial skeleton, but many crucial stages--most notably those relating to the acquisition of squamate skull kinesis--remain unclear. PMID:14700390

  11. At the feet of the dinosaurs: the early history and radiation of lizards.

    PubMed

    Evans, Susan E

    2003-11-01

    Lizards, snakes and amphisbaenians together constitute the Squamata, the largest and most diverse group of living reptiles. Despite their current success, the early squamate fossil record is extremely patchy. The last major survey of squamate palaeontology and evolution was published 20 years ago. Since then, there have been major changes in systematic theory and methodology, as well as a steady trickle of new fossil finds. This review examines our current understanding of the first 150 million years of squamate evolution in the light of the new data and changing ideas. Contrary to previous reports, no squamate fossils are currently documented before the Jurassic. Nonetheless, indirect evidence predicts that squamates had evolved by at least the middle Triassic, and had diversified into existing major lineages before the end of this period. There is thus a major gap in the squamate record at a time when key morphological features were evolving. With the exception of fragmentary remains from Africa and India, Jurassic squamates are known only from localities in northern continents (Laurasia). The situation improves in the Early Cretaceous, but the southern (Gondwanan) record remains extremely poor. This constrains palaeobiogeographic discussion and makes it difficult to predict centres of origin for major squamate clades on the basis of fossil evidence alone. Preliminary mapping of morphological characters onto a consensus tree demonstrates stages in the sequence of acquisition for some characters of the skull and postcranial skeleton, but many crucial stages--most notably those relating to the acquisition of squamate skull kinesis--remain unclear.

  12. The effects of X-ray and UV background radiation on the low-mass slope of the galaxy mass function

    NASA Astrophysics Data System (ADS)

    Hambrick, D. C.; Ostriker, J. P.; Johansson, P. H.; Naab, T.

    2011-06-01

    Even though the dark-matter power spectrum in the absence of biasing predicts a number density of haloes n(M) ∝M-2 (i.e. a Schechter α value of -2) at the low-mass end (M < 1010 M⊙), hydrodynamic simulations have typically produced values for stellar systems in good agreement with the observed value α≃-1. We explain this with a simple physical argument and show that an efficient external gas-heating mechanism (such as the UV background included in all hydro codes) will produce a critical halo mass below which haloes cannot retain their gas and form stars. We test this conclusion with GADGET-2-based simulations using various UV backgrounds, and for the first time we also investigate the effect of an X-ray background. We show that at the present epoch α depends primarily on the mean gas temperature at the star-formation epoch for low-mass systems (z≲ 3): with no background we find α≃-1.5, with UV only α≃-1.0 and with UV and X-rays α≃-0.75. We find the critical final halo mass for star formation to be ˜4 × 108 M⊙ with a UV background and ˜7 × 108 M⊙ with UV and X-rays.

  13. Survival Advantage With the Addition of Radiation Therapy to Chemotherapy in Early Stage Peripheral T-Cell Lymphoma, Not Otherwise Specified

    SciTech Connect

    Zhang, Xi-Mei; Li, Ye-Xiong; Wang, Wei-Hu; Jin, Jing; Wang, Shu-Lian; Liu, Yue-Ping; Song, Yong-Wen; Fang, Hui; Ren, Hua; Zhou, Li-Qiang; Liu, Xin-Fan; Yu, Zi-Hao

    2013-03-15

    Purpose: Early stage peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS) is rare. The purpose of this study was to evaluate the outcome of treatment as well as the potential role of radiation therapy in PTCL-NOS. Methods and Materials: Thirty-five patients with early stage PTCL-NOS were included. There were 13 patients with stage I disease and 22 with stage II. All patients except 1 received doxorubicin-based chemotherapy alone (n=13) or a combination of chemotherapy and radiation therapy (CMT) (n=21). Results: The 3-year overall survival (OS) and progression-free survival (PFS) rates for the entire group were 41.3% and 25.7%, respectively. The addition of radiation therapy to chemotherapy significantly improved OS and PFS in early stage PTCL-NOS. The 3-year OS and PFS rates were 49.7% and 33.3% for CMT, compared with 23.1% (P=.042) and 15.4% (P=.035) for chemotherapy alone, respectively. The prognosis for patients who achieved a complete response (CR) was significantly better than that observed in those who did not achieve a CR. Conclusions: Despite the aggressive clinical course of early stage PTCL-NOS, additional radiation therapy has a significant impact on outcome. The integration of local radiation therapy into more effective systemic therapies may further improve survival.

  14. SYNCHROTRON RADIATION, FREE ELECTRON LASER, APPLICATION OF NUCLEAR TECHNOLOGY, ETC. Employing a Cerenkov detector for the thickness measurement of X-rays in a scattering background

    NASA Astrophysics Data System (ADS)

    Li, Shu-Wei; Kang, Ke-Jun; Wang, Yi; Li, Jin; Li, Yuan-Jing; Zhang, Qing-Jun

    2010-12-01

    The variation in environmental scattering background is a major source of systematic errors in X-ray inspection and measurement systems. As the energy of these photons consisting of environmental scattering background is much lower generally, the Cerenkov detectors having the detection threshold are likely insensitive to them and able to exclude their influence. A thickness measurement experiment is designed to verify the idea by employing a Cerenkov detector and an ionizing chamber for comparison. Furthermore, it is also found that the application of the Cerenkov detectors is helpful to exclude another systematic error from the variation of low energy components in the spectrum incident on the detector volume.

  15. Individualized Prediction of Overall Survival After Postoperative Radiation Therapy in Patients With Early-Stage Cervical Cancer: A Korean Radiation Oncology Group Study (KROG 13-03)

    SciTech Connect

    Lee, Hyun Jin; Han, Seungbong; Kim, Young Seok; Nam, Joo-Hyun; Kim, Hak Jae; Kim, Jae Weon; Park, Won; Kim, Byoung-Gie; Kim, Jin Hee; Cha, Soon Do; Kim, Juree; Lee, Ki-Heon; Yoon, Mee Sun; and others

    2013-11-15

    Purpose: A nomogram is a predictive statistical model that generates the continuous probability of a clinical event such as death or recurrence. The aim of the study was to construct a nomogram to predict 5-year overall survival after postoperative radiation therapy for stage IB to IIA cervical cancer. Methods and Materials: The clinical data from 1702 patients with early-stage cervical cancer, treated at 10 participating hospitals from 1990 to 2011, were reviewed to develop a prediction nomogram based on the Cox proportional hazards model. Demographic, clinical, and pathologic variables were included and analyzed to formulate the nomogram. The discrimination and calibration power of the model was measured using a concordance index (c-index) and calibration curve. Results: The median follow-up period for surviving patients was 75.6 months, and the 5-year overall survival probability was 87.1%. The final model was constructed using the following variables: age, number of positive pelvic lymph nodes, parametrial invasion, lymphovascular invasion, and the use of concurrent chemotherapy. The nomogram predicted the 5-year overall survival with a c-index of 0.69, which was superior to the predictive power of the International Federation of Gynecology and Obstetrics (FIGO) staging system (c-index of 0.54). Conclusions: A survival-predicting nomogram that offers an accurate level of prediction and discrimination was developed based on a large multi-center study. The model may be more useful than the FIGO staging system for counseling individual patients regarding prognosis.

  16. ["Epistemic Negotiations" and the Pluralism of the Radiation Protection Regime: The Determination of Radiation Protection Standards for the General Population in the Early Years After World War II].

    PubMed

    Higuchi, Toshihiro

    2015-10-01

    Radiation protection standards for the general population have constituted one of the most controversial subjects in the history of atomic energy uses. This paper reexamines the process in which the first such standards evolved in the early postwar period. While the existing literature has emphasized a "collusion" between the standard-setters and users, the paper seeks to examine the horizontal relationship among the standard-setters. It first examines a series of expert consultations between the United States and the United Kingdom. Representing a different configuration of power and interest, the two failed to agree on the assessment of genetic damage and cancer induction whose occurrence might have no threshold and therefore be dependent on the population size. This stalemate prevented the International Commission on Radiological Protection (ICRP), established in 1950, from formulating separate guidelines for the general public. Situations radically changed when the Bikini incident in 1954 led to the creation of more scientific panels. One such panel under the U.S. Academy of Sciences enabled the geneticists to bridge their internal divide, unanimously naming 100 mSv as the genetically permissible dose for the general population. Not to be outdone, ICRP publicized its own guidelines for the same purpose. The case examined in this paper shows that the standard-setting process is best understood as a series of "epistemic negotiations" among and within the standard-setters, whose agendas were determined from the outset but whose outcomes were not.

  17. Dynamics of the early universe and the initial conditions for inflation in a model with radiation and a Chaplygin gas

    NASA Astrophysics Data System (ADS)

    Monerat, G. A.; Oliveira-Neto, G.; Silva, E. V. Corrêa; Filho, L. G. Ferreira; Romildo, P., Jr.; Fabris, J. C.; Fracalossi, R.; Gonçalves, S. V. B.; Alvarenga, F. G.

    2007-07-01

    The early universe is modeled through the quantization of a Friedmann-Robertson-Walker (FRW) model with positive curvature. In this model, the universe is filled by two fluids: radiation and Chaplygin gas. The quantization of these models is made by following the Wheeler-DeWitt prescriptions. Using the Schutz formalism, the time notion is recovered and the Wheeler-DeWitt equation transforms into a time dependent Schrödinger equation, which rules the dynamics of the early universe, under the action of an effective potential Veff. Using a finite differences method and the Crank-Nicholson scheme, in a code implemented in the program OCTAVE, we solve the corresponding time dependent Schrödinger equation and obtain the time evolution of an initial wave packet. This wave packet satisfies appropriate boundary conditions. The calculation of the tunneling probabilities shows that the universe may emerge from the Planck era in an inflationary phase. It also shows that the tunneling probability is a function of the mean energy of the initial wave packet and of the two parameters of the Chaplygin gas. We also show a comparison between these results and those obtained by the WKB approximation.

  18. Overexpression of α1-protease Inhibitor and Galectin-1 in Radiation-induced Early Phase of Pulmonary Fibrosis

    PubMed Central

    Im, Hee-Soon; Kim, Hyung-Doo; Song, Jie-Young; Han, Youngsoo; Lee, Do-Youn; Kim, Chan-Wha

    2006-01-01

    Purpose Radiation-induced pulmonary fibrosis (RIF) is a significant complication of radiotherapy for lung cancer. Despite the large number of studies, the molecular mechanisms of RIF are poorly understood. Therefore, the complex protein expression pattern in RIF was characterized by identifying the proteins with an altered expression level after thorax irradiation using two-dimensional electrophoresis (2-DE) and mass spectrometry. Materials and Methods A mouse model of RIF was used to examine the alteration of the lung proteome because of availability of murine data related to human cases and the abundance of murine fibrotic lung samples. A mouse model of RIF was induced in radiosensitive C57BL/6 mice. Twenty-one weeks after 25 Gy irradiation, hematoxylin-eosin staining and hydroxyproline assay confirmed the early-phase pulmonary fibrosis. Results Lung samples from the irradiated and age-matched control mice were used to generate 16 high quality 2-DE gels containing approximately 1,000 spots. Of the 31 significantly up- or down-regulated protein spots, 17 were identified by MALDI-TOF/MS. Conclusions Two important upregulated proteins were found, the α1-protease inhibitor and galectin-1, which might be used as potential markers for the early phase of RIF. PMID:19771266

  19. Involved-Site Image-Guided Intensity Modulated Versus 3D Conformal Radiation Therapy in Early Stage Supradiaphragmatic Hodgkin Lymphoma

    SciTech Connect

    Filippi, Andrea Riccardo; Ciammella, Patrizia; Piva, Cristina; Ragona, Riccardo; Botto, Barbara; Gavarotti, Paolo; Merli, Francesco; Vitolo, Umberto; Iotti, Cinzia; Ricardi, Umberto

    2014-06-01

    Purpose: Image-guided intensity modulated radiation therapy (IG-IMRT) allows for margin reduction and highly conformal dose distribution, with consistent advantages in sparing of normal tissues. The purpose of this retrospective study was to compare involved-site IG-IMRT with involved-site 3D conformal RT (3D-CRT) in the treatment of early stage Hodgkin lymphoma (HL) involving the mediastinum, with efficacy and toxicity as primary clinical endpoints. Methods and Materials: We analyzed 90 stage IIA HL patients treated with either involved-site 3D-CRT or IG-IMRT between 2005 and 2012 in 2 different institutions. Inclusion criteria were favorable or unfavorable disease (according to European Organization for Research and Treatment of Cancer criteria), complete response after 3 to 4 cycles of an adriamycin- bleomycin-vinblastine-dacarbazine (ABVD) regimen plus 30 Gy as total radiation dose. Exclusion criteria were chemotherapy other than ABVD, partial response after ABVD, total radiation dose other than 30 Gy. Clinical endpoints were relapse-free survival (RFS) and acute toxicity. Results: Forty-nine patients were treated with 3D-CRT (54.4%) and 41 with IG-IMRT (45.6%). Median follow-up time was 54.2 months for 3D-CRT and 24.1 months for IG-IMRT. No differences in RFS were observed between the 2 groups, with 1 relapse each. Three-year RFS was 98.7% for 3D-CRT and 100% for IG-IMRT. Grade 2 toxicity events, mainly mucositis, were recorded in 32.7% of 3D-CRT patients (16 of 49) and in 9.8% of IG-IMRT patients (4 of 41). IG-IMRT was significantly associated with a lower incidence of grade 2 acute toxicity (P=.043). Conclusions: RFS rates at 3 years were extremely high in both groups, albeit the median follow-up time is different. Acute tolerance profiles were better for IG-IMRT than for 3D-CRT. Our preliminary results support the clinical safety and efficacy of advanced RT planning and delivery techniques in patients affected with early stage HL, achieving complete

  20. DNA repair efficiency in germ cells and early mouse embryos and consequences for radiation-induced transgenerational genomic damage

    SciTech Connect

    Marchetti, Francesco; Wyrobek, Andrew J.

    2009-01-18

    Exposure to ionizing radiation and other environmental agents can affect the genomic integrity of germ cells and induce adverse health effects in the progeny. Efficient DNA repair during gametogenesis and the early embryonic cycles after fertilization is critical for preventing transmission of DNA damage to the progeny and relies on maternal factors stored in the egg before fertilization. The ability of the maternal repair machinery to repair DNA damage in both parental genomes in the fertilizing egg is especially crucial for the fertilizing male genome that has not experienced a DNA repair-competent cellular environment for several weeks prior to fertilization. During the DNA repair-deficient period of spermatogenesis, DNA lesions may accumulate in sperm and be carried into the egg where, if not properly repaired, could result in the formation of heritable chromosomal aberrations or mutations and associated birth defects. Studies with female mice deficient in specific DNA repair genes have shown that: (i) cell cycle checkpoints are activated in the fertilized egg by DNA damage carried by the sperm; and (ii) the maternal genotype plays a major role in determining the efficiency of repairing genomic lesions in the fertilizing sperm and directly affect the risk for abnormal reproductive outcomes. There is also growing evidence that implicates DNA damage carried by the fertilizing gamete as a mediator of postfertilization processes that contribute to genomic instability in subsequent generations. Transgenerational genomic instability most likely involves epigenetic mechanisms or error-prone DNA repair processes in the early embryo. Maternal and embryonic DNA repair processes during the early phases of mammalian embryonic development can have far reaching consequences for the genomic integrity and health of subsequent generations.

  1. Risk of Cerebrovascular Events in Elderly Patients After Radiation Therapy Versus Surgery for Early-Stage Glottic Cancer

    SciTech Connect

    Hong, Julian C.; Kruser, Tim J.; Gondi, Vinai; Mohindra, Pranshu; Cannon, Donald M.; Harari, Paul M.; Bentzen, Søren M.

    2013-10-01

    Purpose: Comprehensive neck radiation therapy (RT) has been shown to increase cerebrovascular disease (CVD) risk in advanced-stage head-and-neck cancer. We assessed whether more limited neck RT used for early-stage (T1-T2 N0) glottic cancer is associated with increased CVD risk, using the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database. Methods and Materials: We identified patients ≥66 years of age with early-stage glottic laryngeal cancer from SEER diagnosed from 1992 to 2007. Patients treated with combined surgery and RT were excluded. Medicare CPT codes for carotid interventions, Medicare ICD-9 codes for cerebrovascular events, and SEER data for stroke as the cause of death were collected. Similarly, Medicare CPT and ICD-9 codes for peripheral vascular disease (PVD) were assessed to serve as an internal control between treatment groups. Results: A total of 1413 assessable patients (RT, n=1055; surgery, n=358) were analyzed. The actuarial 10-year risk of CVD was 56.5% (95% confidence interval 51.5%-61.5%) for the RT cohort versus 48.7% (41.1%-56.3%) in the surgery cohort (P=.27). The actuarial 10-year risk of PVD did not differ between the RT (52.7% [48.1%-57.3%]) and surgery cohorts (52.6% [45.2%-60.0%]) (P=.89). Univariate analysis showed an increased association of CVD with more recent diagnosis (P=.001) and increasing age (P=.001). On multivariate Cox analysis, increasing age (P<.001) and recent diagnosis (P=.002) remained significantly associated with a higher CVD risk, whereas the association of RT and CVD remained not statistically significant (HR=1.11 [0.91-1.37,] P=.31). Conclusions: Elderly patients with early-stage laryngeal cancer have a high burden of cerebrovascular events after surgical management or RT. RT and surgery are associated with comparable risk for subsequent CVD development after treatment in elderly patients.

  2. Topical AC-11 abates actinic keratoses and early squamous cell cancers in hairless mice exposed to Ultraviolet A (UVA) radiation.

    PubMed

    Mentor, Julian M; Etemadi, Amir; Patta, Abrienne M; Scheinfeld, Noah

    2015-04-01

    AC-11 is an aqueous extract of the botanical, Uncaria tomentosa, which has a variety of effects that enhance DNA repair and down regulate inflammation. AC-11 is essentially free of oxindole alkaloids (< 0.05%, w/w) but contains more than 8% carboxy alkyl esters (CAEs) as their active ingredients. Three groups of 10 outbred SK-1 hairless or SK-II hairless strains of mice each were treated with AC-11 at 0.5%, 1.5%, and 3.0% in a non-irritating, dye-free, perfume-free, and fragrance-free vanishing cream vehicle. Ten mice used vehicle only and 10 were untreated. Each concentration of AC-11 and was applied daily to the backs of the mice prior to exposure to a 1,600-watt solar simulator used in this work (Solar Light Co. Philadelphia, PA) emitting (mainly Ultraviolet A (UVA) and B (UVB) radiation) duration of the experimental period with UVB wavelengths was filtered out with a 1.0 cm Schott WG 345 filter. AC-11 with a peak absorption at 200nm does act as a sun block. We tested for and focused on clinical appearance of mice and histological appearance of tumors in mice rather than metrics of radiation generated inflammation. Tumor progression scores were assigned as follows: 4+ = extensive tumor development; 3+ = early malignancies (raised palpable plaques)(early squamous cell cancers) 2+ = firm scaling, palpable keratosis (actinic keratoses); 1+ = light scaling with erythema. Following a total cumulative dose of 738 J/cm2, 85.7% all of the irradiated control animals, which did not receive AC-11 had precancerous actinic keratosis (AK)-type lesions (2+) (64.3% versus 42.9%) or early squamous cell carcinoma (SCC) (3+) (21.4% vs. 4.8%), in comparison with 47.7 % of AC-11-treated animals. There were no significant differences between the AC-11 groups. Three months after cessation of exposure to UVA radiation, the lesions in all but three of the 14 animals which were treated with AC-11 that were still evaluable irradiated with UVA radiation progressed to papillomas and frank

  3. Topical AC-11 abates actinic keratoses and early squamous cell cancers in hairless mice exposed to Ultraviolet A (UVA) radiation.

    PubMed

    Mentor, Julian M; Etemadi, Amir; Patta, Abrienne M; Scheinfeld, Noah

    2015-04-16

    AC-11 is an aqueous extract of the botanical, Uncaria tomentosa, which has a variety of effects that enhance DNA repair and down regulate inflammation. AC-11 is essentially free of oxindole alkaloids (< 0.05%, w/w) but contains more than 8% carboxy alkyl esters (CAEs) as their active ingredients. Three groups of 10 outbred SK-1 hairless or SK-II hairless strains of mice each were treated with AC-11 at 0.5%, 1.5%, and 3.0% in a non-irritating, dye-free, perfume-free, and fragrance-free vanishing cream vehicle. Ten mice used vehicle only and 10 were untreated. Each concentration of AC-11 and was applied daily to the backs of the mice prior to exposure to a 1,600-watt solar simulator used in this work (Solar Light Co. Philadelphia, PA) emitting (mainly Ultraviolet A (UVA) and B (UVB) radiation) duration of the experimental period with UVB wavelengths was filtered out with a 1.0 cm Schott WG 345 filter. AC-11 with a peak absorption at 200nm does act as a sun block. We tested for and focused on clinical appearance of mice and histological appearance of tumors in mice rather than metrics of radiation generated inflammation. Tumor progression scores were assigned as follows: 4+ = extensive tumor development; 3+ = early malignancies (raised palpable plaques)(early squamous cell cancers) 2+ = firm scaling, palpable keratosis (actinic keratoses); 1+ = light scaling with erythema. Following a total cumulative dose of 738 J/cm2, 85.7% all of the irradiated control animals, which did not receive AC-11 had precancerous actinic keratosis (AK)-type lesions (2+) (64.3% versus 42.9%) or early squamous cell carcinoma (SCC) (3+) (21.4% vs. 4.8%), in comparison with 47.7 % of AC-11-treated animals. There were no significant differences between the AC-11 groups. Three months after cessation of exposure to UVA radiation, the lesions in all but three of the 14 animals which were treated with AC-11 that were still evaluable irradiated with UVA radiation progressed to papillomas and frank

  4. Distortion of the Microwave Blackbody Background Radiation Implied by the Baryon-symmetric Cosmology of Omnes and the Galaxy Formation Theory of Stecker and Puget

    NASA Technical Reports Server (NTRS)

    Stecker, F. W.; Puget, J. L.

    1973-01-01

    Theories on the evolution of the universe are evaluated. Particular attention was given to Omnes and Stecker and Puget theories. Data cover distortion of the microwave black body background energy distribution at red shifts between 10,000 and 1.000, and black body distortion due to antimatter and annihilation reactions.

  5. Application of conditionally replicating adenoviruses in tumor early diagnosis technology, gene-radiation therapy and chemotherapy.

    PubMed

    Li, Shun; Ou, Mengting; Wang, Guixue; Tang, Liling

    2016-10-01

    Conditionally replicating adenoviruses (CRAds), or known as replication-selective adenoviruses, were discovered as oncolytic gene vectors several years ago. They have a strong ability of scavenging tumor and lesser toxicity to normal tissue. CRAds not only have a tumor-killing ability but also can combine with gene therapy, radiotherapy, and chemotherapy to induce tumor cell apoptosis. In this paper, we review the structure of CRAds and CRAd vectors and summarize the current application of CRAds in tumor detection as well as in radiotherapy and suicide gene-mediating chemotherapy. We also propose further research strategies that can improve the application value of CRAds, including enhancing tumor destruction effect, further reducing toxic effect, reducing immunogenicity, constructing CRAds that can target tumor stem cells, and trying to use mesenchymal stem cells (MSCs) as the carriers for oncolytic adenoviruses. As their importance to cancer diagnosis, gene-radiation, and chemotherapy, CRAds may play a considerable role in clinical diagnosis and various cancer treatments in the future. PMID:27557721

  6. The development of early pediatric models and their application to radiation absorbed dose calculations

    SciTech Connect

    Poston, J.W.

    1989-12-31

    This presentation will review and describe the development of pediatric phantoms for use in radiation dose calculations . The development of pediatric models for dose calculations essentially paralleled that of the adult. In fact, Snyder and Fisher at the Oak Ridge National Laboratory reported on a series of phantoms for such calculations in 1966 about two years before the first MIRD publication on the adult human phantom. These phantoms, for a newborn, one-, five-, ten-, and fifteen-year old, were derived from the adult phantom. The ``pediatric`` models were obtained through a series of transformations applied to the major dimensions of the adult, which were specified in a Cartesian coordinate system. These phantoms suffered from the fact that no real consideration was given to the influence of these mathematical transformations on the actual organ sizes in the other models nor to the relation of the resulting organ masses to those in humans of the particular age. Later, an extensive effort was invested in designing ``individual`` pediatric phantoms for each age based upon a careful review of the literature. Unfortunately, the phantoms had limited use and only a small number of calculations were made available to the user community. Examples of the phantoms, their typical dimensions, common weaknesses, etc. will be discussed.

  7. The development of early pediatric models and their application to radiation absorbed dose calculations

    SciTech Connect

    Poston, J.W.

    1989-01-01

    This presentation will review and describe the development of pediatric phantoms for use in radiation dose calculations . The development of pediatric models for dose calculations essentially paralleled that of the adult. In fact, Snyder and Fisher at the Oak Ridge National Laboratory reported on a series of phantoms for such calculations in 1966 about two years before the first MIRD publication on the adult human phantom. These phantoms, for a newborn, one-, five-, ten-, and fifteen-year old, were derived from the adult phantom. The pediatric'' models were obtained through a series of transformations applied to the major dimensions of the adult, which were specified in a Cartesian coordinate system. These phantoms suffered from the fact that no real consideration was given to the influence of these mathematical transformations on the actual organ sizes in the other models nor to the relation of the resulting organ masses to those in humans of the particular age. Later, an extensive effort was invested in designing individual'' pediatric phantoms for each age based upon a careful review of the literature. Unfortunately, the phantoms had limited use and only a small number of calculations were made available to the user community. Examples of the phantoms, their typical dimensions, common weaknesses, etc. will be discussed.

  8. Early Clinical Experience With Kilovoltage Image-Guided Radiation Therapy for Interfraction Motion Management

    SciTech Connect

    Lawson, Joshua D. Fox, Tim; Elder, Eric; Nowlan, Adam; Davis, Lawrence; Keller, James; Crocker, Ian

    2008-01-01

    Interest in image-guided radiation therapy (IGRT) reflects the desire to minimize interfraction positioning variability. Using a kilovoltage (kV) imaging unit mounted to a traditional LINAC allows daily matching of kV images to planning digitally reconstructed radiographs (DRRs). We quantify and evaluate the significance of calculated deviation from the intended isocenter. Since September 2004, 117 patients with various malignancies were treated using the On-Board Imaging (OBI) system, with 2088 treatment sessions. Patients were positioned by the treating therapist; orthogonal images were then obtained with the OBI unit. Couch shifts were made, aligning bony anatomy to the initial simulation image. Routine port films were performed weekly (after that day's OBI session). Ninety percent of all lateral, longitudinal, and vertical shifts were less than 0.8 cm, 0.6 cm, and 0.7 cm, respectively. The median vector shift for each anatomic site was: 0.42 cm for head and neck, 0.40 cm for CNS, 0.59 cm for GU/prostate, and 0.73 cm for breast; shift magnitude did not change with successive OBI sessions. The use of OBI effectively corrects setup variability. These shifts are typically small and random. The use of OBI likely can replace weekly port films for isocenter verification; however, OBI does not provide field shape verification.

  9. Early clinical experience with kilovoltage image-guided radiation therapy for interfraction motion management.

    PubMed

    Lawson, Joshua D; Fox, Tim; Elder, Eric; Nowlan, Adam; Davis, Lawrence; Keller, James; Crocker, Ian

    2008-01-01

    Interest in image-guided radiation therapy (IGRT) reflects the desire to minimize interfraction positioning variability. Using a kilovoltage (kV) imaging unit mounted to a traditional LINAC allows daily matching of kV images to planning digitally reconstructed radiographs (DRRs). We quantify and evaluate the significance of calculated deviation from the intended isocenter. Since September 2004, 117 patients with various malignancies were treated using the On-Board Imaging (OBI) system, with 2088 treatment sessions. Patients were positioned by the treating therapist; orthogonal images were then obtained with the OBI unit. Couch shifts were made, aligning bony anatomy to the initial simulation image. Routine port films were performed weekly (after that day's OBI session). Ninety percent of all lateral, longitudinal, and vertical shifts were less than 0.8 cm, 0.6 cm, and 0.7 cm, respectively. The median vector shift for each anatomic site was: 0.42 cm for head and neck, 0.40 cm for CNS, 0.59 cm for GU/prostate, and 0.73 cm for breast; shift magnitude did not change with successive OBI sessions. The use of OBI effectively corrects setup variability. These shifts are typically small and random. The use of OBI likely can replace weekly port films for isocenter verification; however, OBI does not provide field shape verification. PMID:18973853

  10. Early Clinical Outcomes Using Proton Radiation for Children With Central Nervous System Atypical Teratoid Rhabdoid Tumors

    SciTech Connect

    De Amorim Bernstein, Karen; Sethi, Roshan; Trofimov, Alexei; Zeng, Chuan; Fullerton, Barbara; Yeap, Beow Y.; Ebb, David; Tarbell, Nancy J.; Yock, Torunn I.; MacDonald, Shannon M.

    2013-05-01

    Purpose: Atypical teratoid/rhabdoid tumor (AT/RT) is an uncommon and aggressive tumor that often affects infants. Irradiation improves survival but has traditionally been avoided in patients under the age of 3 due to the increasing risk of neurocognitive side effects. We report the first cohort of AT/RT patients treated with proton therapy. Methods and Materials: All patients with AT/RT treated at Massachusetts General Hospital (MGH) Frances H. Burr Proton Beam Therapy Benter between July 2004 and November 2011 were included in this study. All patients were treated with 3-dimensional conformal proton therapy (3D-CPT). Results: Ten consecutive patients of a median 2.3 years of age and with a median follow-up of 27.3 months (range, 11.3-99.4 months) were identified. Two patients suffered distant relapse; 1 patient was successfully treated with involved field irradiation and chemotherapy, while the second patient died of disease. At last follow-up, 9 patients were alive without evidence of disease. Proton radiation demonstrated increasing sparing of the cerebrum, temporal lobe, cochlea, and hypothalamus. Conclusions: Initial clinical outcomes with proton therapy are favorable. The advantages of proton therapy are particularly suited to the treatment of AT/RT, a tumor that often requires irradiation treatment at an age when avoiding irradiation to healthy tissues is most desirable.

  11. Monitoring sources of nuclear radiation in space. Part 1: Early 1984 observations, revision

    NASA Astrophysics Data System (ADS)

    Share, G. H.; Kurfess, J. D.; Messina, D. C.

    1989-05-01

    Nuclear radiation from the reactor powered satellite COSMOS 1579 was monitored by the gamma ray spectrometer (GRS) on NASA's Solar Maximum Mission satellite (SMM). Gamma rays from the RORSAT (Radar Ocean Reconnaissance Satellites) were detected about every 4 days as it passed within about 500 km of SMM. In addition, events attributed to positrons emitted from the outer shell of COSMOS 1579 were detected on the average of once every about 1.5 days. These positrons were detected at large distances (less than or = 5000 km) from COSMOS after being stored in the earth's magnetic field for seconds or minutes. The rate of the positron detections is about a factor of two higher than observed for most of the earlier RORSAT's detected by SMM. At present, this increase is unexplained. The qualitative features of the measured gamma-ray spectrum from COSMOS 1579 are similar to those of preceding satellites; however, the spectral features are clearer. A model is presented for the origin of these features which suggests the presence of significant amounts of beryllium, sodium, potassium, molybdenum and lithium and/or hydrogen lying with tens of gm/sq cm of material. There is also spectral evidence for the presence of either iron or aluminum. Based on this model, a conservative lower limit was obtained to the thermal power of the reactor on COSMOS 1579. This lower limit is 30 kW.

  12. The origin and early radiation of the therapsid mammal-like reptiles: a palaeobiological hypothesis.

    PubMed

    Kemp, T S

    2006-07-01

    The replacement of the basal synapsid pelycosaurs by the more 'mammal-like' therapsids in the Permian was an important event in the history of tetrapods because it initiated the eventual transition to the mammals. It is also an example of taxon replacement in the fossil record that is unusually amenable to explanation, based on a combination of analysis of the biological significance of the inferred character changes, with the stratigraphic, palaeogeographic and palaeoecological circumstances of the time. An hypothesis is presented in which the origin of the therapsids resulted from a correlated progression of character evolution leading to higher levels of metabolic activity and homeostatic regulation of the body. It was a response to the availability of a seasonally arid, savanna-like biome. The subsequent explosive radiation of therapsids was associated with habitat expansion made possible by the Mid-Permian development of geographical continuity between that biome and the temperate biomes. The final extinction of the pelycosaurs was a case of incumbent replacement by the new therapsid lineages. PMID:16780524

  13. Historical background.

    PubMed Central

    Epstein, M A

    2001-01-01

    The persisting ancient view of cancer as a contagious disease ended with 19th century scientific investigations which seemed to show it was not. The resulting dogma against an infectious cause for cancer produced great prejudice in the scientific community against the first report of an oncogenic virus by Rous early in the 20th century and, even in the 1950s, against Gross's finding of a murine leukaemia virus and a murine virus causing solid tumours. The Lucké frog renal carcinoma virus was the first cancer-associated herpesvirus. Intriguingly, an environmental factor, ambient temperature, determines virus genome expression in the poikilothermic frog cells. Although an alpha-herpesvirus, Marek's disease virus of chickens shares some aspects of biological behaviour with Epstein-Barr virus (EBV) of man. Very significantly, its lymphomas are the first naturally occurring malignancy to be controlled by an antiviral vaccine, with implications for human virus-associated cancers. The circumstances and climate of opinion in which successive gamma-herpesviruses were discovered are described. The identification of EBV involved two unconventionalities: its finding in cultured Burkitt's lymphoma cells when no human lymphoid cell had ever been maintained in vitro, and its recognition in the absence of biological activity by the then new technique of electron microscopy. These factors engendered hostility to its acceptance as a new human tumour-associated virus. The EBV-like agents of Old World apes and monkeys and the T-lymphotropic gamma-herpesviruses of New World monkeys were found at about the same time, not long after the discovery of EBV. For many years these were thought to be the only gamma-herpesviruses of non-human primates; however, very recently B-lymphotropic EBV-like agents have been identified in New World species as well. Mouse herpesvirus 68 came to light by chance during a search for arboviruses and has become important as a laboratory model because of its

  14. Radiation Therapy, Cardiac Risk Factors, and Cardiac Toxicity in Early-Stage Breast Cancer Patients

    SciTech Connect

    Doyle, John J.; Wang Jian; McBride, Russell; Neugut, Alfred I.; Grann, Victor R. ||; Jacobson, Judith S. |; Grann, Alison; Hershman, Dawn ||. E-mail: dlh23@columbia.edu

    2007-05-01

    Purpose: The benefits of adjuvant radiation therapy (RT) for breast cancer may be counterbalanced by the risk of cardiac toxicity. We studied the cardiac effects of RT and the impact of pre-existing cardiac risk factors (CRFs) in a population-based sample of older patients with breast cancer. Methods and Materials: In the Surveillance, Epidemiology and End-Results (SEER)-Medicare database of women {>=}65 years diagnosed with Stages I to III breast cancer from January 1, 1992 to December 31, 2000, we used multivariable logistic regression to model the associations of demographic and clinical variables with postmastectomy and postlumpectomy RT. Using Cox proportional hazards regression, we then modeled the association between treatment and myocardial infarction (MI) and ischemia in the 10 or more years after diagnosis, taking the predictors of treatment into account. Results: Among 48,353 women with breast cancer; 19,897 (42%) were treated with lumpectomy and 26,534 (55%) with mastectomy; the remainder had unknown surgery type (3%). Receipt of RT was associated with later year of diagnosis, younger age, fewer comorbidities, nonrural residence, and chemotherapy. Postlumpectomy RT was also associated with white ethnicity and no prior history of heart disease (HD). The RT did not increase the risk of MI. Presence of MI was associated with age, African American ethnicity, advanced stage, nonrural residence, more than one comorbid condition, a hormone receptor-negative tumor, CRFs and HD. Among patients who received RT, tumor laterality was not associated with MI outcome. The effect of RT on the heart was not influenced by HD or CRFs. Conclusion: It appears unlikely that RT would increase the risk of MI in elderly women with breast cancer, regardless of type of surgery, tumor laterality, or history of CRFs or HD, for at least 10 years.

  15. Early Duplication of a Single MHC IIB Locus Prior to the Passerine Radiations

    PubMed Central

    Eimes, John A.; Lee, Sang-im; Townsend, Andrea K.; Jablonski, Piotr; Nishiumi, Isao; Satta, Yoko

    2016-01-01

    A key characteristic of MHC genes is the persistence of allelic lineages over macroevolutionary periods, often through multiple speciation events. This phenomenon, known as trans-species polymorphism (TSP), is well documented in several major taxonomic groups, but has less frequently been observed in birds. The order Passeriformes is arguably the most successful terrestrial vertebrate order in terms of diversity of species and ecological range, but the reasons for this success remain unclear. Passerines exhibit the most highly duplicated MHC genes of any major vertebrate taxonomic group, which may generate increased immune response relative to other avian orders with fewer MHC loci. Here, we describe phylogenetic patterns of the MHC IIB in the passerine family Corvidae. Our results indicate wide-spread TSP within this family, with at least four supported MHC IIB allelic lineages that predate speciation by many millions of years. Markov chain Monte Carlo simulations indicate that divergence of these lineages occurred near the time of the divergence of the Passeriformes and other avian orders. We suggest that the current MHC diversity observed in passerines is due in part to the multiple duplication of a single MHC locus, DAB1, early in passerine evolution and that subsequent duplications of these paralogues have contributed to the enormous success of this order by increasing their ability to recognize and mount immune responses to novel pathogens. PMID:27658204

  16. Macrophage function in murine allogeneic bone marrow radiation chimeras in the early phase after transplantation

    SciTech Connect

    Roesler, J.; Baccarini, M.; Vogt, B.; Lohmann-Matthes, M.L. )

    1989-08-01

    We tested several of the functions of macrophages (M phi) in the early phase after allogeneic bone marrow transfer to get information about this important aspect of the nonspecific immune system in the T-cell-deficient recipient. On days 3-5 after transfer, the number of M phi was reduced in the spleen, liver, lungs, and peritoneal cavity (Pe). The phagocytosis of sheep red blood cells (SRBC) by these M phi was normal or even enhanced, as in the case of Pe-M phi. Already on days 8-12 after transfer, the number of M phi in spleen and liver exceeded that of controls, whereas the number was still reduced in lungs and Pe. We examined their ability to kill P815 tumor cells, to produce tumor necrosis factor-alpha (TNF alpha), to phagocytose SRBC, to produce reactive oxygen intermediates (ROI) in vitro and to kill Listeria monocytogenes in vivo. Most functions were normal and often even enhanced, depending on the organ origin, but the ability of Pe-M phi to produce ROI was reduced. Proliferative response to macrophage colony-stimulating factor (M-CSF) and killing of YAC-1 tumor cells revealed a high frequency of macrophage precursor cells in the spleen and liver and a high natural killer (NK) activity in the liver. Altogether, enhanced nonspecific immune function, especially preactivated M phi, may enable chimeras to survive attacks by opportunistic pathogens.

  17. Temperature Measurement of a Miniature Ceramic Heater in the Presence of an Extended Interfering Background Radiation Source Using a Multiwavelength Pyrometer

    NASA Technical Reports Server (NTRS)

    Ng, Daniel

    1999-01-01

    Temperature measurement of small (millimeter size) objects is generally difficult and demanding. Measurement involving ceramic materials using the traditional one- and two-color pyrometer is difficult because of their complex optical properties, such as low emissivity which may vary with both temperature and wavelength. Pyrometry applications in an environment with an interfering radiation source of extended dimension adds extra complexity to the process. We show that the multiwavelength pyrometer successfully measured the temperatures of a millimeter (mm) size ceramic heater under these demanding conditions.

  18. Myocardial hydroxyproline reduced by early administration of methylprednisolone or ibuprofen to rabbits with radiation-induced heart disease

    SciTech Connect

    Reeves, W.C.; Cunningham, D.; Schwiter, E.J.; Abt, A.; Skarlatos, S.; Wood, M.A.; Whitesell, L.

    1982-05-01

    The ability of methylprednisolone (MP) and ibuprofen (IB) to reduce the severity of the late state of radiation-induced heart disease was assessed in 57 New Zealand white rabbits. Before and shortly after cardiac irradiation, 15 rabbits received i.v. MP, 30 mg/kg twice daily for 3 days, and 15 others received IB, 12.5 mg/kg twice daily for 2 days. No drug was administered to 14 irradiated rabbits, and neither irradiation nor drugs were administered to 13 rabbits that served as controls, All 15 rabbits treated with MP and 13 of the 15 treated with IB lived for 100 days. Only seven of the untreated, irradiated rabbits lived that long. Longevity of each treated group of rabbits was better (p less than 0.01 and 0.05) than that of the untreated, irradiated rabbits. Surviving rabbits were killed 100 days after irradiation. Pericarditis (p less than 0.05) and pericardial effusion (p less than 0.01) were less frequent in the treated, irradiated groups than in the untreated, irradiated rabbits. At least some rabbits in each irradiated group had microscopic evidence of myocardial fibrosis. The fibrosis was quantitated by determination of myocardial hydroxyproline concentrations (MHP). MHP concentration in the untreated, irradiated rabbits was greater than in those treated with MP (p less than 0.05) or IB (p less than 0.01) and in the untreated, unirradiated rabbits (p less than 0.01). Early administration of MP or IB retarded the development of myocardial fibrosis, pericarditis and pericardial effusion, and improved survival in this experimental model of radiation-induced heart disease.

  19. Myocardial hydroxyproline reduced by early administration of methylprednisolone or ibuprofen to rabbits with radiation-induced heart disease

    SciTech Connect

    Reeves, W.C.; Cunningham, D.; Schwiter, E.J.; Abt, A.; Skarlatos, S.; Wood, M.A.; Whitesell, L.

    1982-05-01

    The ability of methylprednisolone (MP) and ibuprofen (IB) to reduce the severity of the late state of radiation-induced heart disease was assessed in 57 New Zealand white rabbits. Before and shortly after cardiac irradiation, 15 rabbits received i.v. MP, 30 mg/kg twice daily for 3 days, and 15 others received IB, 12.5 mg/kg twice daily for 2 days. No drug administered to 14 irradiated rabbits, and neither irradiation nor drugs were administered to 13 rabbits that served as controls. All 15 rabbits treated with MP and 13 of the 15 treated with IB lived for 100 days. Only seven of the untreated, irradiated rabbits lived that long. Longevity of each treated group of rabbits was better (p < 0.01 and 0.05) than that of the untreated, irradiated rabbits. Surviving rabbits were killed 100 days after irradiation. Pericarditis (p < 0.05) and pericardial effusion (p < 0.01) were less frequent in the treated, irradiated groups than in the untreated, irradiated rabbits. At least some rabbits in each irradiated group had microscopic evidence of myocardial fibrosis. The fibrosis was quantitated by determination of myocardial hydroxyproline concentrations (MHP). MHP concentration in the untreated, irradiated rabbits was greater than in those treated with MP (p < 0.05) or IB (p < 0.01) and in the untreated, unirradiated rabbits (p < 0.01). Early administrative of MP or IB retarded the development of myocardial fibrosis, pericarditis and pericardial effusin, and improved survival in this experimental model of radiation-induced heart disease.

  20. Dietary feeding of silibinin prevents early biomarkers of UVB radiation-induced carcinogenesis in SKH-1 hairless mouse epidermis.

    PubMed

    Gu, Mallikarjuna; Dhanalakshmi, Sivanandhan; Singh, Rana P; Agarwal, Rajesh

    2005-05-01

    Solar radiation is the causal etiologic factor in the development of nonmelanoma skin cancer (NMSC). Depletion of the stratospheric ozone layer leads to an increase in ambient UV radiation loads, which are expected to further raise skin cancer incidence in many temperate parts of the world, including the United States, suggesting that skin cancer chemopreventive approaches via biomarker efficacy studies or vice versa are highly warranted. Based on our recent study reporting strong efficacy of silibinin against photocarcinogenesis, we assessed here the protective effects of its dietary feeding on UVB-induced biomarkers involved in NMSC providing a mechanistic rationale for an early-on silibinin efficacy in skin cancer prevention. Dietary feeding of silibinin at 1% dose (w/w) to SKH-1 hairless mice for 2 weeks before a single UVB irradiation at 180 mJ/cm(2) dose resulted in a strong and significant (P < 0.001) decrease in UVB-induced thymine dimer-positive cells and proliferating cell nuclear antigen, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling, and apoptotic sunburn cells together with an increase (P < 0.001) in p53 and p21/cip1-positive cell population in epidermis. These findings suggest that dietary feeding of silibinin affords strong protection against UVB-induced damages in skin epidermis by (a) either preventing DNA damage or enhancing repair, (b) reducing UVB-induced hyperproliferative response, and (c) inhibiting UVB-caused apoptosis and sunburn cell formation, possibly via silibinin-caused up-regulation of p53 and p21/cip1 as major UVB-damage control sensors.