Science.gov

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

    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.

  4. 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.

  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. Cosmic Background Radiation

    NASA Astrophysics Data System (ADS)

    Sidharth, B. G.; Valluri, S. R.

    2015-08-01

    It is shown that a collection of photons with nearly the same frequency exhibits a "condensation" type of phenomenon corresponding to a peak intensity. The observed cosmic background radiation can be explained from this standpoint. We have obtained analogous results by extremization of the occupation number for photons with the use of the Lambert W function. Some of the interesting applications of this function are briefly discussed in the context of graphene which exhibits an interesting two dimensional structure with several characteristic properties and diverse practical applications.

  7. The early radiation of stem group molluscs against the environmental background

    NASA Astrophysics Data System (ADS)

    Gubanov, A. P.

    2003-04-01

    The first helcionelloid molluscs appeared in the late Nemakit-Daldynian and were forerunners of the sudden molluscan diversification of the Cambrian explosion. The diversification of Mollusca is coincided with global changes in lithosphere, hydrosphere, atmosphere, and biosphere coincident with the rearrangement of the Late Proterozoic supercontinent Rodinia, a distinct shift in oceanic water geochemistry, and a sudden abundance of shelled multicellular organisms. Some of these changes have left indicators in the morphology and chemical properties of molluscan shells that allow reconstruction of global settings which are essential for understanding early molluscan evolution. A combination of tectonic and climatic cyclic changes is resulted in a major global transgression at the beginning of the Cambrian and the formation of extensive shallow water habitats within which the first molluscs expanded. Diversification into new ecological niches has been recognised in two evolutionary-adaptive lineages. The lineage from Oelandiella to Watsonella shows adaptation to a soft substrate and infaunal mode of life. In contrast, the Oelandiella-Helcionella lineage was an adaptation to a harder substrate. Appearance of large helcionelloids with associated archaeocyathan reefs in the middle Tommotian may suggest evolution of a browsing carnivorous habit capable of supporting a considerably larger body. Despite of a few such examples, most helcionelloids remained a small size until the Early Ordovician. Early Cambrian helcionelloids show considerable morphological diversity providing a fertile ground for speculation about early molluscan evolution. While almost the all molluscan classes are known from the Cambro-Ordovician transition, the relationship of these, including Tergomya, Gastropoda, Cephalopoda, and Rostroconchia to helcionelloids remains highly problematic. Analysis of morphological variation and evolutionary trends within the earliest molluscs may support derivation of

  8. Physics of the Cosmic Microwave Background Radiation

    NASA Astrophysics Data System (ADS)

    Wands, David; Piattella, Oliver F.; Casarini, Luciano

    The cosmic microwave background (CMB) radiation provides a remarkable window onto the early universe, revealing its composition and structure. In these lectures we review and discuss the physics underlying the main features of the CMB.

  9. The Spectrumof the Cosmic Background Radiation: Early and RecentMeasurements from the White Mountain Research Station

    SciTech Connect

    Smoot, G.F.

    1985-09-01

    The White Mountain Research Station has provided a support facility at a high, dry, radio-quiet site for measurements that have established the blackbody character of the cosmic microwave background radiation. This finding has confirmed the interpretation of the radiation as a relic of the primeval fireball and helped to establish the hot Big Bang theory as the standard cosmological model.

  10. Ultraviolet Background Radiation (Preprint)

    DTIC Science & Technology

    1991-03-01

    5.4 Apollo-Soyuz 3 5 5.5 Evidence for Scattering From Dust ? 3 8 5.6 More Evidence For Scattering From Dust ? 4 0 5.7 More Observations 4 2...Emission from cold interstellar dust . This has been observed by IRAS as the 100 u.m cosmic cirrus (64). The existence of such dust at moderate and... DUST 4 6 CONCLUSIONS 4 7 6.1 Spectral Structure in the Diffuse 4 7 Ultraviolet Background 6.2 Is There Light Scattered From Dust ? 4 7 6.3

  11. 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…

  12. 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.

  13. 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.

  14. 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

  15. Light bending in radiation background

    SciTech Connect

    Kim, Jin Young; Lee, Taekoon E-mail: tlee@kunsan.ac.kr

    2014-01-01

    We consider the velocity shift of light in presence of radiation emitted by a black body. Within geometric optics formalism we calculate the bending angle of a light ray when there is a gradient in the energy density. We model the bending for two simplified cases. The bending angle is proportional to the inverse square power of the impact parameter (∝1/b{sup 2}) when the dilution of energy density is spherically symmetric. The bending angle is inversely proportional to the impact parameter (∝1/b) when the energy density dilutes cylindrically. Assuming that a neutron star is an isothermal black body, we estimate the order of magnitude for such bending angle and compare it with the bending angle by magnetic field.

  16. Background ionising radiation: a pictorial perspective.

    PubMed

    Bibbo, Giovanni; Piotto, Lino

    2014-09-01

    Ionising radiation from natural sources, known as background radiation, has existed on earth since the earth's formation. The exposure of humans and other living creatures to this radiation is a feature of the earth's environment which is continuing and inescapable. The word "radiation" brings fear to many people: a fear of the unknown, as human's senses cannot detect the presence of ionising radiation. In this study, a catalogue of images of the distribution of radioactivity in every day objects and foods has been produced using an imaging plate from a computed radiography cassette. The aim of the study is that by visually demonstrating that every day objects and foods are radioactive would alleviate the fear of "radiation" by becoming aware that we live in a radioactive environment and even our body is radioactive.

  17. 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.

  18. 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.

  19. Modeling background radiation in Southern Nevada.

    PubMed

    Haber, Daniel A; Burnley, Pamela C; Adcock, Christopher T; Malchow, Russell L; Marsac, Kara E; Hausrath, Elisabeth M

    2017-02-06

    Aerial gamma ray surveys are an important tool for national security, scientific, and industrial interests in determining locations of both anthropogenic and natural sources of radioactivity. There is a relationship between radioactivity and geology and in the past this relationship has been used to predict geology from an aerial survey. The purpose of this project is to develop a method to predict the radiologic exposure rate of the geologic materials by creating a high resolution background model. The intention is for this method to be used in an emergency response scenario where the background radiation environment is unknown. Two study areas in Southern Nevada have been modeled using geologic data, images from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), geochemical data, and pre-existing low resolution aerial surveys from the National Uranium Resource Evaluation (NURE) Survey. Using these data, geospatial areas that are homogenous in terms of K, U, and Th, referred to as background radiation units, are defined and the gamma ray exposure rate is predicted. The prediction is compared to data collected via detailed aerial survey by the Department of Energy's Remote Sensing Lab - Nellis, allowing for the refinement of the technique. By using geologic units to define radiation background units of exposed bedrock and ASTER visualizations to subdivide and define radiation background units within alluvium, successful models have been produced for Government Wash, north of Lake Mead, and for the western shore of Lake Mohave, east of Searchlight, NV.

  20. High-energy radiation background in space

    NASA Astrophysics Data System (ADS)

    Rester, A. C., Jr.; Trombka, J. I.

    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.

  1. 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.

  2. 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.

  3. X-Ray Background from Early Binaries

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-11-01

    What impact did X-rays from the first binary star systems have on the universe around them? A new study suggests this radiation may have played an important role during the reionization of our universe.Ionizing the UniverseDuring the period of reionization, the universe reverted from being neutral (as it was during recombination, the previous period)to once again being ionized plasma a state it has remained in since then. This transition, which occurred between 150 million and one billion years after the Big Bang (redshift of 6 z 20), was caused by the formation of the first objects energetic enough to reionize the universes neutral hydrogen.ROSAT image of the soft X-ray background throughout the universe. The different colors represent different energy bands: 0.25 keV (red), 0.75 keV (green), 1.5 keV (blue). [NASA/ROSAT Project]Understanding this time period in particular, determining what sources caused the reionization, and what the properties were of the gas strewn throughout the universe during this time is necessary for us to be able to correctly interpret cosmological observations.Conveniently, the universe has provided us with an interesting clue: the large-scale, diffuse X-ray background we observe all around us. What produced these X-rays, and what impact did this radiation have on the intergalactic medium long ago?The First BinariesA team of scientists led by Hao Xu (UC San Diego) has suggested that the very first generation of stars might be an important contributor to these X-rays.This hypothetical first generation, Population III stars, are thought to have formed before and during reionization from large clouds of gas containing virtually no metals. Studies suggest that a large fraction of Pop III stars formed in binaries and when those stars ended their lives as black holes, ensuing accretion from their companions could produceX-ray radiation.The evolution with redshift of the mean X-ray background intensities. Each curve represents a different

  4. 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.

  5. Polarization of the cosmic background radiation

    NASA Astrophysics Data System (ADS)

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

    1981-04-01

    The technique and results of a measurement of the linear polarization of the cosmic background radiation at a wavelength of 9 mm are discussed. Data taken between 1978 May and 1980 February from both the Northern Hemisphere (Berkeley latitude 38 deg N) and the Southern Hemisphere (Lima latitude 12 deg S) over 11 declinations from -37 to +63 deg 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.

  6. 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.

  7. 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.

  8. The local contribution to the microwave background radiation

    NASA Astrophysics Data System (ADS)

    Pecker, Jean-Claude; Narlikar, Jayant V.; Ochsenbein, Francois; Wickramasinghe, Chandra

    2015-04-01

    The observed microwave background radiation (MBR) is commonly interpreted as the relic of an early hot universe, and its observed features (spectrum and anisotropy) are explained in terms of properties of the early universe. Here we describe a complementary, even possibly alternative, interpretation of MBR, first proposed in the early 20th century, and adapt it to modern observations. For example, the stellar Hipparcos data show that the energy density of starlight from the Milky Way, if suitably thermalized, yields a temperature of ∼2.81 K. This and other arguments given here strongly suggest that the origin of MBR may lie, at least in a very large part, in re-radiation of thermalized galactic starlight. The strengths and weaknesses of this alternative radical explanation are discussed.

  9. 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).

  10. 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.

  11. Cosmic Needles versus Cosmic Microwave Background Radiation

    NASA Astrophysics Data System (ADS)

    Li, Aigen

    2003-02-01

    It has been suggested by a number of authors that the 2.7 K cosmic microwave background (CMB) radiation might have arisen from the radiation of ``Population III'' objects thermalized by conducting cosmic graphite/iron needle-shaped dust. Due to a lack of an accurate solution to the absorption properties of exceedingly elongated grains, in existing literature which studies the CMB thermalizing process they are generally modeled as (1) needle-like spheroids in terms of the Rayleigh approximation, (2) infinite cylinders, and (3) antennae. We show here that the Rayleigh approximation is not valid since the Rayleigh criterion is not satisfied for highly conducting needles. We also show that the available intergalactic iron dust, if modeled as infinite cylinders, is not sufficient to supply the required opacity at long wavelengths to obtain the observed isotropy and Planckian nature of the CMB. If appealing to the antenna theory, conducting iron needles with exceedingly large elongations ( >104) appear able to provide sufficient opacity to thermalize the CMB within the iron density limit. But the applicability of the antenna theory to exceedingly thin needles of nanometer/micrometer thickness has not yet been verified.

  12. Background radiation: natural and man-made.

    PubMed

    Thorne, M C

    2003-03-01

    A brief overview and comparison is given of dose rates arising from natural background radiation and the fallout from atmospheric testing of nuclear weapons. Although there are considerable spatial variations in exposure to natural background radiation, it is useful to give estimates of worldwide average overall exposures from the various components of that background. Cosmic-ray secondaries of low linear energy transfer (LET), mainly muons and photons, deliver about 280 microSv a(-1). Cosmic-ray neutrons deliver about another 100 microSv a(-1). These low- and high-LET exposures are relatively uniform to the whole body. The effective dose rate from cosmogenic radionuclides is dominated by the contribution of 12 microSv a(-1) from 14C. This is due to relatively uniform irradiation of all organs and tissues from low-energy beta particles. Primordial radionuclides and their progeny (principally the 238U and 232Th series, and 40K) contribute about 480 microSv a(-1) of effective dose by external irradiation. This is relatively uniform photon irradiation of the whole body. Internally incorporated 40K contributes a further 165 microSv a(-1) of effective dose in adults, mainly from beta particles, but with a significant gamma component. Equivalent doses from 40K are somewhat higher in muscle than other soft tissues, but the distinction is less than a factor of three. Uranium and thorium series radionuclides give rise to an average effective dose rate of around 120 microSv a(-1). This includes a major alpha particle component, and exposures of radiosensitive tissues in lung, liver, kidney and the skeleton are recognised as important contributors to effective dose. Overall, these various sources give a worldwide average effective dose rate of about 1160 microSv a(-1). Exposure to 222Rn, 220Rn and their short-lived progeny has to be considered separately. This is very variable both within and between countries. For 222Rn and its progeny, a worldwide average effective dose

  13. 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.

  14. 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.

  15. The Local Contribution to the Microwave Background Radiation(MBR)

    NASA Astrophysics Data System (ADS)

    Narlikar, Jayant V.; Pecker, Jean-Claude; Wickramasinghe, N. Ch.

    2010-11-01

    In the early fifties, from the early theories of the big bang universe, Gamow, Alpher & Herman have predicted the existence of a "cosmological" microwave background radiation, corresponding to a black body of a few Kelvins. When, in 1964, Penzias & Wilson, observed a radiation at 2.7K, the scientific world concluded quickly it was a proof, a final proof, of the big bang type cosmologies. But it should be realized that, in the beginning of the XX-th century, several authors, from Guillaume to Eddington, have predicted the same thing in a static Universe. We have redone the calculations of Eddington, and based them on the recent and very accurate photometric results from the satellite Hipparcos. In the absence of any expansion, of any big bang type behaviour, we compute the local temperature induced by the reradiation by local matter of stellar radiation, and we found it to be in excellent agreement with the observations. This result, completed by a careful discussion, could lead to a dramatic revision of the classical cosmological concepts.

  16. 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.

  17. 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.

  18. BACKGROUND RADIATION IN THE UNIVERSE - Short Contributions

    NASA Astrophysics Data System (ADS)

    Davies, R. D.

    A determination of the motion of the Sun and Local Group relative to the backdrop of galaxies extending to 70 Mpc is used to correct the observed dipole anisotropy in the cosmic microwave background. The resultant intrinsic dipole component of ΔT/T = 3±2×10-4 is consistent with no detected anisotropy.

  19. 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.

  20. BACKGROUND RADIATION IN THE UNIVERSE - Short Contributions

    NASA Astrophysics Data System (ADS)

    Barrow, J. D.; Juszkiewicz, R.; Sonoda, D. H.

    The authors predict the possible microwave background temperature distributions in anisotropic and inhomogeneous universes close to the Friedmann model. Homogeneous, anisotropic universes are found to possess either quadrupole or hot-spot temperature variations. The detailed appearance of the hot-spot is predicted. The discovery of such a feature would demonstrate the universe to be open and allow the total density to be measured directly.

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

    PubMed

    Dobrzyński, Ludwik; 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.

  2. 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

  3. 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,…

  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. 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.

  8. On the omnipresent background gamma radiation of the continuous spectrum

    NASA Astrophysics Data System (ADS)

    Banjanac, R.; Maletić, D.; Joković, D.; Veselinović, N.; Dragić, A.; Udovičić, V.; Aničin, I.

    2014-05-01

    The background spectrum of a germanium detector, shielded from the radiations arriving from the lower and open for the radiations arriving from the upper hemisphere, is studied by means of absorption measurements, both in a ground level and in an underground laboratory. The low-energy continuous portion of this background spectrum that peaks at around 100 keV, which is its most intense component, is found to be of very similar shape at the two locations. It is established that it is mostly due to the radiations of the real continuous spectrum, which is quite similar to the instrumental one. The intensity of this radiation is in our cases estimated to about 8000 photons/(m2s·2π·srad) in the ground level laboratory, and to about 5000 photons/(m2s·2π·srad) in the underground laboratory, at the depth of 25 m.w.e. Simulations by GEANT4 and CORSIKA demonstrate that this radiation is predominantly of terrestrial origin, due to environmental gamma radiations scattered off the materials that surround the detector (the "skyshine radiation"), and to a far less extent to cosmic rays of degraded energy.

  9. Cosmic microwave background radiation of black hole universe

    NASA Astrophysics Data System (ADS)

    Zhang, T. X.

    2010-11-01

    Modifying slightly the big bang theory, the author has recently developed a new cosmological model called black hole universe. This new cosmological model is consistent with the Mach principle, Einsteinian general theory of relativity, and observations of the universe. The origin, structure, evolution, and expansion of the black hole universe have been presented in the recent sequence of American Astronomical Society (AAS) meetings and published recently in a scientific journal: Progress in Physics. This paper explains the observed 2.725 K cosmic microwave background radiation of the black hole universe, which grew from a star-like black hole with several solar masses through a supermassive black hole with billions of solar masses to the present universe with hundred billion-trillions of solar masses. According to the black hole universe model, the observed cosmic microwave background radiation can be explained as the black body radiation of the black hole universe, which can be considered as an ideal black body. When a hot and dense star-like black hole accretes its ambient materials and merges with other black holes, it expands and cools down. A governing equation that expresses the possible thermal history of the black hole universe is derived from the Planck law of black body radiation and radiation energy conservation. The result obtained by solving the governing equation indicates that the radiation temperature of the present universe can be ˜2.725 K if the universe originated from a hot star-like black hole, and is therefore consistent with the observation of the cosmic microwave background radiation. A smaller or younger black hole universe usually cools down faster. The characteristics of the original star-like or supermassive black hole are not critical to the physical properties of the black hole universe at present, because matter and radiation are mainly from the outside space, i.e., the mother universe.

  10. 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.

  11. 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.

  12. Background radiation measurements at high power research reactors

    NASA Astrophysics Data System (ADS)

    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.; 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.; Yeh, M.; Yen, Y.-R.; Zhang, C.; Zhang, X.

    2016-01-01

    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. 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. Effect of natural background radiation on dermatoglyphic traits.

    PubMed

    Bhasin, M K; Malik, S L; Grewal, M S; Singh, I P; Sudarshan, K J; Kochupillai, N; Verma, I C

    1980-01-01

    Long term exposure to natural background radiation could cause gross abnormalities in individuals and at the population level. Studies conducted on the coastal Kerala population which is known to be receiving fifteen times the normal permissible dose of radiation support this. This study aims at understanding the deviations, if any, in the normal human variation as a result of such high natural radiation. A detailed quantitative and qualitative dermatoglyphic study was done on two communities i.e. Hindus and Christians, living separately in the radiation area. The significant differences were observed between control and exposed groups with regard to d-t ridge count, distances c-t and angle atd. The susceptibility of the axial triradius to environmental distrubances is discussed.

  14. The Mystery of the Cosmic Diffuse Ultraviolet Background Radiation

    NASA Astrophysics Data System (ADS)

    Henry, Richard Conn; Murthy, Jayant; Overduin, James; Tyler, Joshua

    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.

  15. 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.

  16. Radiative properties of the background aerosol: absorption component of extinction.

    PubMed

    Clarke, A D; Charlson, R J

    1985-07-19

    The light-scattering and light-absorption coefficients of the global background aerosol define its single-scatter albedo. Continuous, simultaneous measurements of these optical coefficients were made on a daily basis for the remote marine mid-troposphere; such measurements are essential for assessment of the effects of aerosol on atmospheric radiative transfer. Measurements of light-absorption coefficients made at the Mauna Loa Observatory in Hawaii were higher than expected, and the single-scatter albedo was lower than the value often used in radiative transfer models. Soot appears to be the most likely primary absorber, and hemispheric dispersal of this combustion-derived material is suggested.

  17. 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.

  18. 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

  19. Background radiation measurements at high power research reactors

    DOE PAGES

    Ashenfelter, J.; Yeh, M.; Balantekin, B.; ...

    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

  20. Cosmic Microwave Background Radiation of Black Hole Universe

    NASA Astrophysics Data System (ADS)

    Zhang, Tianxi

    2009-05-01

    Recently, the author has proposed an alternative cosmological model called black hole universe. According to this model, the universe originated from a hot star-like black hole with several solar masses, and gradually grew up through a supermassive black hole with billion solar masses to the present state with hundred billion-trillion solar masses by accreting ambient materials and merging with other black holes. The entire space is structured with infinite layers hierarchically. The innermost three layers are the universe that we are living, the outside called mother universe, and the inside star-like and supermassive black holes called child universes. The outermost layer is infinite in radius and limits to zero for both the mass density and absolute temperature. The observed cosmic microwave background radiation can be explained as the black body radiation of the black hole universe. When a hot and dense star-like black hole accretes its ambient matter and radiation or merges with other black holes, it expands and cools down. In terms of the Planck law of the black body radiation, a possible thermal history of the black hole universe is obtained. The result shows that the temperature of the present universe can be 3 K as observed if the universe originated from a hot star-like black hole. The initial properties (e.g., temperature, angular momentum, etc.) of the star-like black hole are not critical to the present universe, because most matter and radiation are from the mother universe. Therefore, the black hole universe model is also consistent with the observation of the cosmic microwave background radiation.

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. The ROSCOE MANUAL. Volume 27: Natural background radiation

    NASA Astrophysics Data System (ADS)

    Hamlin, D. A.; Schoonover, M. R.

    1980-07-01

    The Natural Background Radiation Module computes the Earth's natural upwelling spectral radiance (from 2 to 5 micrometers) by averaging over paths in an Earth-tangent cone with vertex at each selected altitude. The processes contributing to the radiance are emission from air, Earth's surface, and clouds and reflection of solar radiation from Earth's surface and clouds; attenuation is by molecules and aerosols. The Module integrates ROSCOE-IR models for atmosphere, atmospheric thermal emission, molecular transmittance, aerosols, clouds, Earth's surface characterization and radiance, solar radiation, and upwelling natural radiation. The last 3 models are documented fully; other models (three of which were developed by other organizations) are documented mainly in terms of functions performed, inputs, and outputs. The user selects the modeled Earth's surface from one of seven categories (with possibly an associated descriptor): Lambertian surface (and diffuse reflectance), wind-ruffled water (and wind speed), snow (and its age parameter), sand, soil, foliage, and urban material (and degree-of-urbanization parameter).

  7. 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

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

    NASA Astrophysics Data System (ADS)

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

    1981-03-01

    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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Background radiation measurements at 2200 ft depth in limestone mine.

    NASA Astrophysics Data System (ADS)

    Olling Back, Henning; Vogelaar, R. Bruce; Johnson, D. Nathan

    2003-10-01

    An active limestone mine in southwestern Virginia is being investigated as a possible site for detectors requiring a low muon flux. The current depth of the mine is 2200 feet. However, the mining operations continue to follow a vain of pure limestone at a 30-degree downward plane under a rising escarpment, and so greater depths can be achieved relatively quickly. With over 50 miles of drifts, many 100 ft high and 40 ft wide, and drive in access, this is a potential venue for future low background detectors. We will be reporting initial measurements of the muon flux as a function of zenith angle, as well as the ambient gamma radiation from the surrounding rock.

  1. 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.

  2. 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.

  3. 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.

  4. Formation of Subgalactic Clouds under Ultraviolet Background Radiation

    NASA Astrophysics Data System (ADS)

    Kitayama, Tetsu; Ikeuchi, Satoru

    2000-02-01

    The effects of the ultraviolet (UV) background radiation on the formation of subgalactic clouds are studied by means of one-dimensional hydrodynamical simulations. The radiative transfer of the ionizing photons caused by the absorption by H I, He I, and He II, neglecting the emission, is explicitly taken into account. We find that the complete suppression of collapse occurs for the clouds with circular velocities typically in the range Vc~15-40 km s-1 and the 50% reduction in the cooled gas mass with Vc~20-55 km s-1. These values depend most sensitively on the collapse epoch of the cloud, the shape of the UV spectrum, and the evolution of the UV intensity. Compared with the optically thin case, previously investigated by Thoul & Weinberg in 1996, the absorption of the external UV photons by the intervening medium systematically lowers the above threshold values by ΔVc~5 km s-1. Whether the gas can contract or keeps expanding is roughly determined by the balance between the gravitational force and the thermal pressure gradient when it is maximally exposed to the external UV flux. Based on our simulation results, we discuss a number of implications on galaxy formation, cosmic star formation history, and the observations of quasar absorption lines. In the Appendix, we derive analytical formulae for the photoionization coefficients and heating rates, which incorporate the frequency/direction-dependent transfer of external photons.

  5. 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

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

    NASA Astrophysics Data System (ADS)

    Ressell, M. Ted; Turner, Michael S.

    1989-10-01

    The spectrum of diffuse extragalactic background radiation (DEBRA) at wavelengths from 105 to 10-24 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.

  7. 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.

  8. 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

  9. Temporal Dependence of Chromosomal Aberration on Radiation Quality and Cellular Genetic Background

    NASA Technical Reports Server (NTRS)

    Lu, Tao; Zhang, Ye; Krieger, Stephanie; Yeshitla, Samrawit; Goss, Rosalin; Bowler, Deborah; Kadhim, Munira; Wilson, Bobby; Wu, Honglu

    2017-01-01

    Radiation induced cancer risks are driven by genetic instability. It is not well understood how different radiation sources induce genetic instability in cells with different genetic background. Here we report our studies on genetic instability, particularly chromosome instability using fluorescence in situ hybridization (FISH), in human primary lymphocytes, normal human fibroblasts, and transformed human mammary epithelial cells in a temporal manner after exposure to high energy protons and Fe ions. The chromosome spread was prepared 48 hours, 1 week, 2 week, and 1 month after radiation exposure. Chromosome aberrations were analyzed with whole chromosome specific probes (chr. 3 and chr. 6). After exposure to protons and Fe ions of similar cumulative energy (??), Fe ions induced more chromosomal aberrations at early time point (48 hours) in all three types of cells. Over time (after 1 month), more chromosome aberrations were observed in cells exposed to Fe ions than in the same type of cells exposed to protons. While the mammary epithelial cells have higher intrinsic genetic instability and higher rate of initial chromosome aberrations than the fibroblasts, the fibroblasts retained more chromosomal aberration after long term cell culture (1 month) in comparison to their initial frequency of chromosome aberration. In lymphocytes, the chromosome aberration frequency at 1 month after exposure to Fe ions was close to unexposed background, and the chromosome aberration frequency at 1 month after exposure to proton was much higher. In addition to human cells, mouse bone marrow cells isolated from strains CBA/CaH and C57BL/6 were irradiated with proton or Fe ions and were analyzed for chromosome aberration at different time points. Cells from CBA mice showed similar frequency of chromosome aberration at early and late time points, while cells from C57 mice showed very different chromosome aberration rate at early and late time points. Our results suggest that relative

  10. Background radiation and cancer mortality in Bavaria: an ecological analysis.

    PubMed

    Körblein, Alfred; Hoffmann, Wolfgang

    2006-01-01

    The authors investigated a possible association between background gamma radiation (BGR) and cancer and infant mortality rates. In an in-country ecological study, they performed a population-weighted linear regression of cancer (infant) mortality rates on BGR, adjusted for unemployment rate and population density. Crude cancer rates showed a highly significant increase with BGR: 38 excess cases per 100,000 person-years per millisievert/year (p < .0001). After adjusting for unemployment rate and population density, the authors found that the excess absolute risk reduced to 23.6 cases per 100,000 person-years per mSv/year (p = .0014). The corresponding excess relative risk was 10.2% (95% confidence interval = 3.9-16.7) per mSv/year. The excess relative risk for infant mortality rates was 24% (95% confidence interval = 9-42) per mSv/year. The cancer risk derived from this ecological study is 0.24/Sv, which compares with an International Commission on Radiological Protection value of 0.05/Sv. However, because they are based on highly aggregated data, the results should be interpreted with caution.

  11. 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.

  12. 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.

  13. 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

  14. Thailand radiation monitoring program: a preliminary result analysis of the country's background radiation.

    PubMed

    Krisanangkura, Piyawan; Udomsomporn, Suchin

    2014-08-01

    Environmental monitoring in the context of nuclear-related activities refers to the measurements of ambient gamma dose rates in the environment and radioactivity in air, water, soil etc. Since nuclear power programme in Thailand has not yet been in place, the environment surveillance programme in Thailand currently focuses on establishing 'baseline' environmental radiation levels and radioactivity for the purpose of establishing impacts of future possible sources such as nuclear accidents. The objective is to assure assessments concerning radiation safety for the environment and public. At present, Thailand's monitoring programme operates eight fixed monitoring stations installed in various regions of Thailand; four of which have been in operation since late 2010. The ambient gamma dose rate data are routinely collected from those four real-time monitoring stations starting from October 2010 to September 2011 as described in this study. Also, the radiation data from each station are statically analysed. This study found that the dose rate from the stations located in north and north-east of Thailand showed an apparent tendency towards a diurnal pattern. With these routine data, the average exposure dose rate was possible to estimate in Thailand. Additionally, the assessment of the equivalent dose from natural background radiation was estimated.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. EARLY FAILURES IN AUTOMOBILE PARTS: A BACKGROUND STUDY IN RELIABILITY,

    DTIC Science & Technology

    The early mortality of automobile parts is examined here through the analysis of warranty-claim information from one American manufacturer of...passenger cars for the model year 1961. The Weibull probability distribution is fitted to the early claims data to indicate the trend -- increasing, or

  1. 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.

  2. Boomerang 2003: Measuring the polarization of the Cosmic Microwave Background Radiation

    NASA Astrophysics Data System (ADS)

    Kisner, Theodore Schuyler

    In early 2003, the Boomerang telescope flew for fifteen days over the Antarctic continent suspended from a balloon at an approximate altitude of 100,000 feet. Using a cryogenically cooled, bolometric receiver, it made measurements of the intensity and polarization of the Cosmic Microwave Background (CMB) Radiation in two overlapping sky patches of 100 and 800 square degrees. A spatial analysis of this data provides confirmation of previous measurements of the multipole angular power spectrum of the temperature anisotropies of the CMB. This data also provides power spectra of the polarization and temperature- polarization correlations that are competitive with previous experiments. Cosmological parameters estimated from these angular power spectra are consistent with a "standard" Lambda-CDM universe where inflation was adiabatic.

  3. Early detection of ovarian cancer: background, rationale, and structure of the Yale Early Detection Program.

    PubMed Central

    Schwartz, P. E.; Chambers, J. T.; Taylor, K. J.; Pellerito, J.; Hammers, L.; Cole, L. A.; Yang-Feng, T. L.; Smith, P.; Mayne, S. T.; Makuch, R.

    1991-01-01

    Ovarian cancer has received national attention as a highly virulent disease. Its lack of early warning symptoms and the failure to develop highly sensitive screening tests have led some physicians to recommend prophylactic oophorectomies to women with relatives who have had ovarian cancer. Others have recommended routine screening of otherwise normal women for CA 125, a circulating tumor marker, and ultrasound examinations. Each of these techniques is associated with substantial false-positive rates that could lead to unnecessary surgery. A review of epidemiologic data suggests that familial ovarian cancer kindreds are rare, but women with first-degree relatives who have had ovarian cancer have a significant risk themselves for developing ovarian cancer. In addition, women with a great number of ovulatory cycles are at an increased risk for the disease. Circulating tumor markers are frequently elevated in women with advanced ovarian cancer, but their value in early detection of ovarian cancer has yet to be established. Advances in endovaginal ultrasound and color Doppler flow technology have significantly improved our ability to assess pelvic organs. This article presents the background, rationale, and structure of the Yale Early Detection Program for ovarian cancer, whose goals are to identify the best techniques for diagnosing ovarian cancer in an early stage, to determine the frequency with which such tests should be employed, to assess false-positive results, and to identify women who might benefit from prophylactic oophorectomies. PMID:1810100

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. BACKGROUND RADIATION MEASUREMENTS AND CANCER RISK ESTIMATES FOR SEBINKARAHISAR, TURKEY.

    PubMed

    Kurnaz, Asli

    2013-07-19

    This paper presents the measurement results of environmental radioactivity levels for Şebinkarahisar district (uranium-thorium area), Giresun, Turkey. The radioactivity concentrations of (238)U, (232)Th, (40)K and the fission product (137)Cs in soil samples collected from 73 regions from the surroundings of the study area were determined. In situ measurements of the gamma dose rate in air were performed in the same 73 locations where the soil samples were collected using a portable NaI detector. Also the mean radioactivity concentrations of (238)U, (232)Th and (40)K in rock samples collected from 50 regions were determined. The mean estimated cancer risk value was found. The seasonal variations of the indoor radon activity concentrations were determined in the 30 dwellings in the study area. In addition, the mean gross alpha, gross beta and radon activities in tap water samples were determined in the same 30 dwellings. The excess lifetime cancer risk was calculated using the risk factors of International Commission on Radiological Protection and Biological Effects of Ionizing Radiation. Radiological maps of the Şebinkarahisar region were composed using the results obtained from this study.

  9. 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.

  10. Early results from the Cosmic Background Explorer (COBE)

    NASA Technical Reports Server (NTRS)

    Mather, J. C.; Hauser, M. G.; Bennett, C. L.; Boggess, N. W.; Cheng, E. S.; Eplee, R. E., Jr.; Freudenreich, H. T.; Gulkis, S.; Isaacman, R. B.; Janssen, M.

    1990-01-01

    The Cosmic Background Explorer, launched 18 Nov. 1989, has nearly completed its first full mapping of the sky with all three of its instruments: A Far Infrared Absolute Spectrometer (FIRAS) covering 0.1 to 10 mm, a set of Differential Microwave Radiometers (DMR) operating at 3.3, 5.7, and 9.6 mm, and a diffuse Infrared Background Experiment (DIRBE) spanning 1 to 300 microns in ten bands. A preliminary map of the sky derived from DIRBE data is presented. Initial cosmological implications include: a limit on the comptonization parameter of 0.001, on the chemical potential parameter of 0.01, a strong limit on the existence of a hot smooth intergalactic medium, and a confirmation that the dipole anisotropy has the spectrum expected from a Doppler shift of a blackbody. There are no significant anisotropies in the microwave sky detected, other than from our own galaxy and a cos theta dipole anisotropy whose amplitude and direction agree with previous data. At shorter wavelengths, the sky spectrum and anisotropies are dominated by emission from local sources of emission within our Galaxy and Solar System. Preliminary comparison of IRAS (Infrared Astronomical Satellite) and DRIBE sky brightnesses toward the ecliptic poles shows the IRAS values to be significantly higher than found by DRIBE at 100 microns. The presence of gain and zero point errors in the IRAS total brightness data is suggested. The spacecraft, instrument designs, and data reduction methods are described.

  11. 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.

  12. Quantum Gravity, very early universe and the cosmic microwave background

    NASA Astrophysics Data System (ADS)

    Gupt, Brajesh; Ashtekar, Abhay

    2017-01-01

    The standard model of cosmology in conjunction with inflation is a robust paradigm of the evolution of our Universe from today all the way up to the energy scale 1016 GeV . However, the framework fails to provide a faithful understanding of the physics at Planck scale since it excludes quantum gravity correction. Furthermore, recent observations reveal the presence of large scale CMB anomalies which could be signatures of new physics preceding inflation. We present a quantum gravitational extension of the current inflationary paradigm and its possible connection with the CMB anomalies. We highlight the predictions for the future observations and potential avenues where the interplay between the UV physics of very early Universe and the IR behavior of large scale perturbations can have interesting implications for late time Universe. NSF

  13. 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.

  14. Multifrequency analysis of cosmic microwave background radiation and radiation transport in simulations of reionization

    NASA Astrophysics Data System (ADS)

    Huffenberger, Kevin Michael

    2006-06-01

    We explore two means for probing cosmology, through multifrequency microwave background measurements and through future observations of the epoch of reionization. We use multi-frequency information in first year Wilkinson Microwave Anisotropy Probe (WMAP) data to search for the Sunyaev-Zel'dovich (SZ) effect. We derive an optimal combination of WMAP cross-spectra to extract SZ, limiting the SZ contribution to less than 2% (95% c.l.) at the first acoustic peak in W band. Under the assumption that the removed radio point sources are not correlated with SZ, this limit implies s 8 < 1.07 at 95% c.l. The next generation of microwave telescopes will study the sky at high resolution, scales where both primary and secondary anisotropies are important. We focus on the Atacama Cosmology Telescope (ACT), simulating observations in three channels, and extracting power spectra in a multifrequency analysis. We find that both radio and infrared extragalactic point sources are important contaminants, but can be effectively removed given three (or more) channels and a good understanding of their frequency dependence. However, improper treatment of the scatter in the point source frequency dependence introduces a large systematic bias. The kinetic SZ effect corrupts measurements of the primordial slope and amplitude on small scales. We discuss the non-Gaussianity of the one- point probability distribution function as a way to constrain the kinetic SZ effect, developing a method for distinguishing this effect. We explore the simulation of maps for ACT, their application to the ACT survey geometry, and filtering techniques to recover signals. Recent work suggests that cosmological fluctuations in reionization developon scales of tens or hundreds of comoving megaparsecs.We build models of ionizing sources from simulations, concluding that a large-scale simulation will require radiation transport from a large fraction of the grid cells. Simulations at a reasonable resolution will have

  15. 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;

  16. DNDO Report: Predicting Solar Modulation Potentials for Modeling Cosmic Background Radiation

    SciTech Connect

    Behne, Patrick Alan

    2016-08-08

    The modeling of the detectability of special nuclear material (SNM) at ports and border crossings requires accurate knowledge of the background radiation at those locations. Background radiation originates from two main sources, cosmic and terrestrial. Cosmic background is produced by high-energy galactic cosmic rays (GCR) entering the atmosphere and inducing a cascade of particles that eventually impact the earth’s surface. The solar modulation potential represents one of the primary inputs to modeling cosmic background radiation. Usosokin et al. formally define solar modulation potential as “the mean energy loss [per unit charge] of a cosmic ray particle inside the heliosphere…” Modulation potential, a function of elevation, location, and time, shares an inverse relationship with cosmic background radiation. As a result, radiation detector thresholds require adjustment to account for differing background levels, caused partly by differing solar modulations. Failure to do so can result in higher rates of false positives and failed detection of SNM for low and high levels of solar modulation potential, respectively. This study focuses on solar modulation’s time dependence, and seeks the best method to predict modulation for future dates using Python. To address the task of predicting future solar modulation, we utilize both non-linear least squares sinusoidal curve fitting and cubic spline interpolation. This material will be published in transactions of the ANS winter meeting of November, 2016.

  17. 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.

  18. 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.

  19. Calculations of background beta-gamma radiation dose through geologic time.

    PubMed

    Karam, P A; Leslie, S A

    1999-12-01

    Life on earth is exposed to a background level of ionizing radiation from a number of sources, including beta and gamma radiation from geologic and biologic materials. Radiation dose from geologic emitters has changed because of the chemical evolution of the continental crust, changes in the relative abundances of 235U and 238U, and the radioactive decay of uranium, thorium, and 40K with time. The radiation dose from internal 40K has decreased by a factor of about eight because of changes in the activity concentration of 40K in potassium over the past 4 billion years. Radiation exposure from geologic materials has decreased from about 1.6 mGy y(-1) to 0.66 mGy y(-1) over the past 4 billion years, and radiation exposure to an organism with a potassium concentration of 250 mmol L(-1) has decreased from about 5.5 to about 0.70 mGy y(-1). Accordingly, background radiation exposure from these two sources has dropped from about 7.0 to 1.35 mGy y(-1) during the time life has existed on Earth. The conservative nature of mutation repair mechanisms in modern organisms suggest that these mechanisms may have evolved in the distant past and that organisms may retain some of the capability of efficiently repairing damage from higher radiation levels than exist at present.

  20. 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}.

  1. 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.

  2. Simulating the Impact of the Natural Radiation Background on Bacterial Systems: Implications for Very Low Radiation Biological Experiments.

    PubMed

    Lampe, Nathanael; Biron, David G; Brown, Jeremy M C; Incerti, Sébastien; Marin, Pierre; Maigne, Lydia; Sarramia, David; Seznec, Hervé; Breton, Vincent

    2016-01-01

    At very low radiation dose rates, the effects of energy depositions in cells by ionizing radiation is best understood stochastically, as ionizing particles deposit energy along tracks separated by distances often much larger than the size of cells. We present a thorough analysis of the stochastic impact of the natural radiative background on cells, focusing our attention on E. coli grown as part of a long term evolution experiment in both underground and surface laboratories. The chance per day that a particle track interacts with a cell in the surface laboratory was found to be 6 × 10-5 day-1, 100 times less than the expected daily mutation rate for E. coli under our experimental conditions. In order for the chance cells are hit to approach the mutation rate, a gamma background dose rate of 20 μGy hr-1 is predicted to be required.

  3. Simulating the Impact of the Natural Radiation Background on Bacterial Systems: Implications for Very Low Radiation Biological Experiments

    PubMed Central

    Lampe, Nathanael; Biron, David G.; Brown, Jeremy M. C.; Incerti, Sébastien; Marin, Pierre; Maigne, Lydia; Sarramia, David; Seznec, Hervé; Breton, Vincent

    2016-01-01

    At very low radiation dose rates, the effects of energy depositions in cells by ionizing radiation is best understood stochastically, as ionizing particles deposit energy along tracks separated by distances often much larger than the size of cells. We present a thorough analysis of the stochastic impact of the natural radiative background on cells, focusing our attention on E. coli grown as part of a long term evolution experiment in both underground and surface laboratories. The chance per day that a particle track interacts with a cell in the surface laboratory was found to be 6 × 10−5 day−1, 100 times less than the expected daily mutation rate for E. coli under our experimental conditions. In order for the chance cells are hit to approach the mutation rate, a gamma background dose rate of 20 μGy hr−1 is predicted to be required. PMID:27851794

  4. LOWER BOUND ON THE COSMIC TeV GAMMA-RAY BACKGROUND RADIATION

    SciTech Connect

    Inoue, Yoshiyuki; Tanaka, Yasuyuki T.

    2016-02-20

    The Fermi gamma-ray space telescope has revolutionized our understanding of the cosmic gamma-ray background radiation in the GeV band. However, investigation on the cosmic TeV gamma-ray background radiation still remains sparse. Here, we report the lower bound on the cosmic TeV gamma-ray background spectrum placed by the cumulative flux of individual detected extragalactic TeV sources including blazars, radio galaxies, and starburst galaxies. The current limit on the cosmic TeV gamma-ray background above 0.1 TeV is obtained as 2.8 × 10{sup −8}(E/100 GeV){sup −0.55} exp(−E/2100GeV)[GeV cm{sup −2} s{sup −1} sr{sup −1}] < E{sup 2}dN/dE < 1.1 × 10{sup −7}(E/100 GeV){sup −0.49} [GeV cm{sup −2} s{sup −1} sr{sup −1}], where the upper bound is set by requirement that the cascade flux from the cosmic TeV gamma-ray background radiation can not exceed the measured cosmic GeV gamma-ray background spectrum. Two nearby blazars, Mrk 421 and Mrk 501, explain ∼70% of the cumulative background flux at 0.8–4 TeV, while extreme blazars start to dominate at higher energies. We also provide the cumulative background flux from each population, i.e., blazars, radio galaxies, and starburst galaxies which will be the minimum requirement for their contribution to the cosmic TeV gamma-ray background radiation.

  5. Thermodynamics of viscous matter and radiation in the early universe

    NASA Astrophysics Data System (ADS)

    Tawfik, A.; Magdy, H.

    2012-05-01

    Assuming that the background geometry is filled with free gas consisting of matter and radiation and no phase transitions being occurred in the early Universe, we discuss the thermodynamics of this {\\it closed} system using classical approaches. We find that essential cosmological quantities, such as Hubble parameter $H$, scale factor $a$ and curvature parameter $k$, can be derived from this simple model, which on one hand fulfills and entirely obeys the laws of thermodynamics. On the other hand, the results are compatible with the Friedmann-Lemaitre-Robertson-Walker model and the Einstein field equations. The inclusion of finite bulk viscosity coefficient derives to important changes in all these cosmological quantities. Accordingly, our picture about the evolution of the Universe and its astrophysical consequences seems to be a subject of a radical revision. We find that $k$ strongly depends on the thermodynamics of background matter. The time scale, at which negative curvature might take place, depends on the relation between the matter content and the total energy. Using quantum and statistical approaches, we assume that the size of the Universe is given by the volume occupied one particle and one photon. Different types of their interactions are taken into account. Expressions for $H$ and $a$ are introduced. Therefore, the expansion of the Universe turns to be accessible.

  6. Self-amplifying Hawking radiation and its background: A numerical study

    NASA Astrophysics Data System (ADS)

    Steinhauer, Jeff; de Nova, Juan Ramón Muñoz

    2017-03-01

    We numerically study an analog black hole with two horizons with parameters similar to a recent experiment. We find that the Hawking radiation exists on a background which contains a density oscillation, a zero-frequency ripple. The Hawking radiation evolves from spontaneous to self-amplifying, while the background ripple grows steadily with no qualitative change. It is seen that the self-amplifying Hawking radiation has a nonzero frequency. This frequency is independent of the reference frame since it is the magnitude of the wave which oscillates, as in a standing wave. The background ripple appears even before the inner horizon is created, in contrast to predictions. Furthermore, we find that technical noise and shot-to-shot variations in the number of atoms are not sufficient to cause the observed correlation function. This work is in agreement with the recent observation of self-amplifying Hawking radiation, and explains some of the features seen. In contrast to some recent works, our study differentiates between the Hawking radiation observed, and the evolution of the background.

  7. 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.

  8. Long-Wavelength Measurements of the Cosmic Microwave BackgroundRadiation Spectrum

    SciTech Connect

    Smoot, G.F.; Bensadoun, M.; Bersanelli, M.; pDe Amici, G.; Kogut,A.; Levine, S.; Witebsky, C.

    1987-02-01

    We have measured the temperature of the cosmic microwave background radiation at wavelengths of 0.33, 3.0, 8.2 and 21.3 cm. These measurements represent a continuation of the work reported by Smoot et al. (1985). The new results have a weighted average of 2.70 {+-} 0.05 K and are consistent with past measurements. They limit the possible distortion of the cosmic microwave background radiation spectrum to less than 6%. The results of all measurements to date are consistent with a Planckian spectrum with temperature 2.74 {+-} 0.02 K spanning a wavelength range of 0.1 to 21 cm.

  9. 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.

  10. Contribution to the ultraviolet metagalactic background from radiative recombination in intervening absorbers

    NASA Astrophysics Data System (ADS)

    Liu, J. M.

    1997-05-01

    Recently, Haardt & Madau (HM) showed that QSO absorption-line systems are not only sinks of the ultraviolet metagalactic background (UMB), but also significant sources of the UMB due to recombination radiation within photoionized absorbers. We demonstrate that the contribution to the UMB from H I and He II recombination radiation may be less than Haardt & Madau's by a factor of about 0.4 if intervening absorbers are modeled as a slab illuminated isotropically on two sides and the recombination radiation is assumed to be isotropic. This is the case which most closely approximates QSOs absorption-line systems.

  11. Analysis of Spectral Variation in Background Gamma Radiation at U.S. Ports of Entry

    SciTech Connect

    Homolka, Kaylee Lynn

    2014-07-01

    This project exists to improve the ability to detect nuclear material crossing the borders. The purpose of my portion of this project was to analyze spectral variations of backgrounds measured by radiation portal monitor detectors at ports of entry using available data to determine whether or not the measured background variation includes changes in the spectral shape in addition to changes in the gross counts.

  12. 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…

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. QUaD: A millimeter-wave polarimeter for observation of the cosmic microwave background radiation

    NASA Astrophysics Data System (ADS)

    Hinderks, James R.

    2005-11-01

    This thesis describes the design and performance of the QUaD experiment and presents some of its earliest results. QUaD is a millimeter-wavelength polarimeter designed for observing the Cosmic Microwave Background (CMB). QUaD was commissioned at the MAPO observatory at the Amundsen-Scott South Pole Station in the Austral Summer of 2004/2005, achieved first light in Feb 2005, and began science observation in May. QUaD observes the CMB with an array of 31 polarization-sensitive Neutron Transmutation Doped (NTD) germanium bolometers split between two frequency bands centered at 100 and 150 GHz. The telescope is a 2.6 m on-axis Cassegrain design with beam sizes of 6.3' and 4.2' at the two respective observing frequencies. The resolution and scan strategy are optimized to probe the CMB E- mode power spectrum over a multipole range of 100 to 2500. The performance of the system has been characterized with commissioning observations and a high signal-to-noise map of the CMB temperature anisotropy has been made over a ~50 square degree area. CMB polarization anisotropies, only recently detected, promise a wealth of new cosmological information. Their observation complements the many successful temperature anisotropy measurements already performed, confirming our basic understanding of the early universe and leading to tighter constraints on cosmological parameters. Furthermore, polarization observations provide a probe of structure since the last scattering surface and promise unique constraints on inflation through the imprint of relict gravitational radiation.

  19. 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.

  20. 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.

  1. Probing Reionization with the Cross-power Spectrum of 21 cm and Near-infrared Radiation Backgrounds

    NASA Astrophysics Data System (ADS)

    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 |\\Delta ^2_{21,NIR}|\\sim 10^{-4} mK nW m-2 sr-1, reached at l ~ 1000 when the mean fraction of ionized hydrogen is \\bar{x}_{i}\\sim 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 × 10-4 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.

  2. 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.

  3. natural background radiation dosimetry in the highest altitude region of Iran.

    PubMed

    Shahbazi-Gahrouei, Daryoush

    2003-09-01

    The natural background radiation has been measured in one of the highest altitude regions (Zagros Mountains), Chaharmahal and Bakhtiari province, in the south west of Iran. The outdoors-environmental monitoring exposure rate of radiation was measured in 200 randomly chosen regions using portable Geiger-Muller and scintillation detectors. Eight measurements were made in each region and an average value was used to calculate the exposure rate from natural background radiation. The average exposure rate was found to be 0.246 microGy/h and the annual average effective dose equivalent was found to be 0.49 mSv. An overall population-weighted mean outdoor dose rate was calculated to be 49 nGy/h, which is higher than the world-wide mean value of 44 nGy/h, as reported by UNSCEAR in 1998, and is comparable to the annual effective dose equivalent of 0.38 mSv. A good correlation between the altitude and the exposure rate was observed, as the higher altitude regions have higher natural background radiation levels.

  4. Many-body heat radiation and heat transfer in the presence of a nonabsorbing background medium

    NASA Astrophysics Data System (ADS)

    Müller, Boris; Incardone, Roberta; Antezza, Mauro; Emig, Thorsten; Krüger, Matthias

    2017-02-01

    Heat radiation and near-field radiative heat transfer can be strongly manipulated by adjusting geometrical shapes, optical properties, or the relative positions of the objects involved. Typically, these objects are considered as embedded in vacuum. By applying the methods of fluctuational electrodynamics, we derive general closed-form expressions for heat radiation and heat transfer in a system of N arbitrary objects embedded in a passive nonabsorbing background medium. Taking into account the principle of reciprocity, we explicitly prove the symmetry and positivity of transfer in any such system. Regarding applications, we find that the heat radiation of a sphere as well as the heat transfer between two parallel plates is strongly enhanced by the presence of a background medium. Regarding near- and far-field transfer through a gas like air, we show that a microscopic model (based on gas particles) and a macroscopic model (using a dielectric contrast) yield identical results. We also compare the radiative transfer through a medium like air and the energy transfer found from kinetic gas theory.

  5. 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.

  6. 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

  7. 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.

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

    PubMed

    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; Panisko, M E; Seifert, A; Warren, G A; Runkle, R C

    2012-11-01

    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.

  9. Scale covariance and G-varying cosmology. II - Thermodynamics, radiation, and the 3 K background

    NASA Technical Reports Server (NTRS)

    Canuto, V. M.; Hsieh, S.-H.

    1979-01-01

    Within the framework of a scale-covariant theory of gravitation, a semiclassical description of particles and photons is given. Thermodynamic relations consistent with the modified conservation equations are derived. Application to a system of radiation shows that the observed 3-K background radiation can be interpreted, within the present framework, as a remnant of equilibrium radiation in the past. As the theory postulates a nonstandard coupling between gravitation and electrodynamics, the assumption that Einstein's theory of gravitation is unchanged forces modifications at the atomic level. The use of Minkowskian spacetime in atomic physics is found to be adequate only over small, but not large, time scales compared with the age of the universe. As a result, a relation between energy and the frequency of a free photon is demonstrated. Possible observational consequences of this relation are discussed.

  10. Ultraviolet Radiation on the Early Earth

    NASA Astrophysics Data System (ADS)

    Quarles, Billy

    2008-03-01

    What gave life the initial spark? Some mythical force that governs all or some natural reaction that was a product of the conditions of environment set in place by physics. There is still much debate, but our search is in a more academic environment. The evolution of the Sun could be an indicator to how the atmosphere has evolved to accommodate life. In the early era of the Earth we do know from other sources that there was no oxygen or ozone to help support life. What made life possible under such harsh conditions. The answer to this inquiry can be found by knowing the UV flux from the Sun during this time period.

  11. 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.

  12. Multi-frequency survey of background radiations of the Universe. The "Cosmological Gene" project. First results

    NASA Astrophysics Data System (ADS)

    Parijskij, Yu. N.; Mingaliev, M. G.; Nizhel'Skii, N. A.; Bursov, N. N.; Berlin, A. B.; Grechkin, A. A.; Zharov, V. I.; Zhekanis, G. V.; Majorova, E. K.; Semenova, T. A.; Stolyarov, V. A.; Tsybulev, P. G.; Kratov, D. V.; Udovitskii, R. Yu.; Khaikin, V. B.

    2011-10-01

    The results of the first stage of the "Cosmological Gene" project of the Russian Academy of Sciences are reported. These results consist in the accumulation of multi-frequency data in 31 frequency channels in the wavelength interval 1-55 cm with maximum achievable statistical sensitivity limited by the noise of background radio sources at all wavelengths exceeding 1.38 cm. The survey region is determined by constraints 00 h < RA < 24 h and 40°30' < DEC < 42°30'. The scientific goals of the project are refined in view of recent proposals to use cosmological background radiation data for the development of a unified physical theory. Experimental data obtained with the RATAN-600 radio telescope are used to refine the contribution of the main "screens" located between the observer and the formation epoch of cosmic background radiation ( z = 1100). Experimental data for synchrotron radiation and free-free noise on scales that are of interest for the anisotropy of cosmic microwave background are reported as well as the contribution of these noise components in millimeter-wave experiments to be performed in the nearest years. The role of dipole radio emission of fullerene-type dust nanostructures is shown to be small. The most precise estimates of the role of background radio sources with inverted spectra are given and these sources are shown to create no serious interference in experiments. The average spectral indices of the weakest sources of the NVSS and FIRST catalogs are estimated. The "saturation" data for all wavelengths allowed a constraint to be imposed on the Sunyaev-Zeldovich noise (the SZ noise) at all wavelengths, and made it possible to obtain independent estimates of the average sky temperature from sources, substantially weaker than those listed in the NVSS catalog. These estimates are inconsistent with the existence of powerful extragalactic synchrotron background associated with radio sources. Appreciable "quadrupole" anisotropy in is detected in the

  13. Modeling background radiation using geochemical data: A case study in and around Cameron, Arizona.

    PubMed

    Marsac, Kara E; Burnley, Pamela C; Adcock, Christopher T; Haber, Daniel A; Malchow, Russell L; Hausrath, Elisabeth M

    2016-12-01

    This study compares high resolution forward models of natural gamma-ray background with that measured by high resolution aerial gamma-ray surveys. The ability to predict variations in natural background radiation levels should prove useful for those engaged in measuring anthropogenic contributions to background radiation for the purpose of emergency response and homeland security operations. The forward models are based on geologic maps and remote sensing multi-spectral imagery combined with two different sources of data: 1) bedrock geochemical data (uranium, potassium and thorium concentrations) collected from national databases, the scientific literature and private companies, and 2) the low spatial resolution NURE (National Uranium Resource Evaluation) aerial gamma-ray survey. The study area near Cameron, Arizona, is located in an arid region with minimal vegetation and, due to the presence of abandoned uranium mines, was the subject of a previous high resolution gamma-ray survey. We found that, in general, geologic map units form a good basis for predicting the geographic distribution of the gamma-ray background. Predictions of background gamma-radiation levels based on bedrock geochemical analyses were not as successful as those based on the NURE aerial survey data sorted by geologic unit. The less successful result of the bedrock geochemical model is most likely due to a number of factors including the need to take into account the evolution of soil geochemistry during chemical weathering and the influence of aeolian addition. Refinements to the forward models were made using ASTER visualizations to create subunits of similar exposure rate within the Chinle Formation, which contains multiple lithologies and by grouping alluvial units by drainage basin rather than age.

  14. 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

  15. 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

  16. Radionuclides and radiation indices of high background radiation area in Chavara-Neendakara placer deposits (Kerala, India).

    PubMed

    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 ((238)U), Thorium ((232)Th) and Potassium ((40)K) are the major sources for radioactivity prevailing in the area. Our statistical analyses reveal the existence of a high positive correlation between (238)U and (232)Th, 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.

  17. 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.

  18. Twisted pair of optic fibers for background removal in radiation fields.

    PubMed

    Liu, P Z Y; Suchowerska, N; McKenzie, D R

    2013-08-01

    In many situations in which an optic fiber carries a signal through a radiation field, an unwanted background signal is produced consisting of fluorescent and/or Cerenkov light. This presents a major problem in the measurement of the light signal, for example, in scintillation dosimetry of medical therapeutic beams. In this paper, we demonstrate a new method of measuring and removing the background signal through the use of a twisted pair of optic fibers. The twisted pair consists of a fiber carrying the scintillation signal that is twisted with a second optic fiber to form a double helix. The two twisted fibers will experience the same radiation environment provided the periodicity of the twist is correlated to the dose rate gradient. An expression for the required twist periodicity is presented. A scintillation dosimeter with a twisted pair optic fiber was tested in a megavoltage beam and found to accurately measure its beam characteristics. The twisted pair approach is not restricted to medical applications and can be used in many situations in which optical signals are carried through radiation fields.

  19. 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.

  20. Predictions of induced background radiations at gamma/X-ray experiment envelopes in NASA spacecraft

    NASA Technical Reports Server (NTRS)

    Fischbein, W. L.; Debiak, T.; Rossi, M.; Stauber, M.; Suh, P.

    1979-01-01

    This work seeks to predict secondary radiation levels induced in spacecraft structures by space protons. The radiations analyzed are secondary neutrons from spallation and evaporation reactions and gamma and beta rays from the decay of induced radioactivity, as sources of interfering background to spaceborne measurements of galactic and planetary gamma rays below 10 MeV. The spacecraft considered are the Multi-Mission Spacecraft (MMS) and the Space Shuttle, modeled as spherical shells. The proton environment is that of the South Atlantic Anomaly, as well as cosmic ray protons. The induced radioactivity is analyzed in terms of its interference with various gamma-ray lines of astrophysical interest, as well as its contribution to several spectral regions of the gamma-ray continuum. The buildup of the line and continuum radioactivity background is predicted for a period of nearly 9 months in orbit (approximately 4100 orbits). In addition, background contributions from cosmic ray electron bremsstrahlung and earth gamma-ray albedo are estimated.

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. Biaxial lidar efficiency increase based on improving spatial selectivity and stability against background radiation

    NASA Astrophysics Data System (ADS)

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

    1996-11-01

    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 & NIR systems is a main cause of a low signal-to-background-noise ratio at the photodetector input, the considerably 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.

  6. 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.

  7. Radiation-induced bystander effect: early process and rapid assessment.

    PubMed

    Wang, Hongzhi; Yu, K N; Hou, Jue; Liu, Qian; Han, Wei

    2015-01-01

    Radiation-induced bystander effect (RIBE) is a biological process that has received attention over the past two decades. RIBE refers to a plethora of biological effects in non-irradiated cells, including induction of genetic damages, gene expression, cell transformation, proliferation and cell death, which are initiated by receiving bystander signals released from irradiated cells. RIBE brings potential hazards to normal tissues in radiotherapy, and imparts a higher risk from low-dose radiation than we previously thought. Detection with proteins related to DNA damage and repair, cell cycle control, proliferation, etc. have enabled rapid assessment of RIBE in a number of research systems such as cultured cells, three-dimensional tissue models and animal models. Accumulated experimental data have suggested that RIBE may be initiated rapidly within a time frame as short as several minutes after radiation. These have led to the requirement of techniques capable of rapidly assessing RIBE itself as well as assessing the early processes involved.

  8. 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.

  9. Fluctuations in radiation backgrounds at high redshift and the first stars

    NASA Astrophysics Data System (ADS)

    Holzbauer, Lauren Nicole

    The first stars to light up our universe are as yet unseen, but there have been many attempts to elucidate their properties. The characteristics of these stars (`Population/Pop III' stars) that we do know lie mostly within theory; they formed out of metal-free hydrogen and helium gas contained in dark matter minihalos at redshifts z 20-30. The extent to which Pop III star formation reached into later times is unknown. Current and near future instruments are incapable of resolving individual Pop III stars. Consequently, astronomers must devise creative means with which to indirectly predict and measure and their properties. In this thesis, we will investigate a few of those means. We use a new method to model fluctuations of the Lyman-Werner (LW) and Lyman-alpha radiation backgrounds at high redshift. At these early epochs the backgrounds are symptoms of a universe newly lit with its first stars. LW photons (11.5-13.6 eV) are of particular interest because they dissociate molecular hydrogen, the primary coolant in the first minihalos that is necessary for star formation. By using a variation of the `halo model', which describes the spatial distribution and clustering of halos, we can efficiently generate power spectra for these backgrounds. Spatial fluctuations in the LW and (indirectly) the Lyman-alpha BG can tell us about the transition from primordial star formation to a more metal-enriched mode that marks the beginning of the second generation of stars in our Universe. The Near Infrared Background (NIRB) has for some time been considered a potential tool with which to indirectly observe the first stars. Ultraviolet (UV) emission from these stars is redshifted into the NIR band, making the NIRB amenable for hunting Pop III stellar signatures. There have been several measurements of the NIRB and subsequent theoretical studies attempting to explain them in recent years. Though controversial, residual levels of the mean NIRB intensity and anisotropies have been

  10. 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.

  11. 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.

  12. Background radiation in the Albuquerque, New Mexico, U.S.A., area

    NASA Astrophysics Data System (ADS)

    Brookins, Douglas G.

    1992-01-01

    Background radiation levels in the Albuquerque, New Mexico, area are elevated when compared to much of the United States. Soil K, U, and Th are somewhat elevated compared to average values in this country and generate roughly 60 mrem per year to the average resident. Cosmic ray contribution, due to the mean elevation of 5,200 ft above sea level, is 80 mrem/yr—well over the average for the United States. Thirty percent of the homes in Albuquerque contain indoor radon levels over the EPA action level of 4 pCi/ℓ compared to 10 12 percent of homes for the entire United States. Indoor radon contributes about 100 300 mrem/yr. Food, beverages, and x-ray doses are assumed at an average-equivalent for the United States and locally yield 96 mrem/yr. Total contributions from other minor sources (color TV, coal, weapons fallout, etc.) are under 10 mrem/yr. Thus total background radiation received by Albuquerque residents is about 330 530 mrem/yr, well in excess of the rest of the United States. The spread in mrem values is due to variations in the contribution from indoor radon.

  13. 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

  14. 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.

  15. 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.

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

    PubMed

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

    2010-04-06

    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.

  17. 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

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

    DOE PAGES

    Tang, Jonathan; Huang, Yurong; Nguyen, David H.; ...

    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

  19. Far-UV Radiation of the Early Sun

    NASA Technical Reports Server (NTRS)

    Heap, Sally

    2005-01-01

    Far-UV radiation is responsible for the photolysis of important greenhouse gases such as CO2, NH3 (ammonia), CH4 (methane) and more generally, the global UV photochemistry of the early atmosphere. In our project, we are concentrating on the young Sun's effect on methane, since UV sunlight (lambda less than 1450 Angstroms) was the main destruction mechanism for methane in the early Earth's atmosphere. Since the UV luminosity of the early Sun cannot be calculated a priori; it can only be estimated from observations of stars similar to the young Sun. We report our results based on Hubble + FUSE spectra of stars selected from Gaidos (1998) Catalog of Nearby Young Solar Analogs (YSA's).

  20. Solar Radiation as Driving Force In Early Evolution

    NASA Technical Reports Server (NTRS)

    Rothschild, Lynn J.; Peterson, David L. (Technical Monitor)

    2002-01-01

    Ultraviolet radiation (UVR) has provided an evolutionary challenge to life on Earth in that it is both an agent of mutation and as well as a selective force. Today surface fluxes of UVR vary diurnally, seasonally, etc. Still, the UVR flux was probably substantially higher during the early phases of evolution, suggesting that its role in evolution was even more prominent during this time. In this presentation, the creative role of UVR in evolution is discussed, specifically in connection with the role that UVR may have played in the evolution of early microbial ecosystems. The presentation will include discussions of the direct influence of UVR on such processes as photosynthesis and genetic damage, as well as the indirect influence of UVR as mediated through the production of reactive oxygen species. These biological effects of UVR will be viewed against the backdrop of the physical nature of the early Earth, surely a very different place then than now.

  1. Federal Guidance Report No. 1: Background Material for the Development of Radiation Protection Standards (Federal Radiation Council)

    EPA Pesticide Factsheets

    This report provides required interim radiation protection recommendations. It includes recommendations for additional research which will provide a firmer basis for the formulation of radiation standards.

  2. The effect of hot gas in early-type galaxies on the cosmic microwave background

    NASA Technical Reports Server (NTRS)

    Trester, Jeffrey J.; Canizares, Claude R.

    1989-01-01

    The effects on the cosmic microwave background which are due to Compton scattering by the hot gas contained in early-type galaxies (the Sunyaev-Zeldovich effect) are computed. Using the known properties of the gas deduced from X-ray observations, it is found that the fractional attenuation DeltaT/T at the center of a gas-rich galaxy is likely to be less than 10 to the -5th, which is just below current limits of detectability. A distribution function is derived for the attenuation which is due to a population of early-type galaxies out to some redshift and the expected rms fluctuations in the background on subarcmin scales are computed. These fluctuations are comparable to those intrinsic to the microwave background in the 'cold dark matter' scenario on these angular scales, but they fall orders of magnitude below the detection limits and below the level of fluctuations expected from nonlinear density perturbations at the epoch of galaxy formation.

  3. Determination of the health hazards due to background radiation sources in the city of Adapazari, Northwestern Turkey.

    PubMed

    Kapdan, Enis; Altinsoy, Nesrin; Karahan, Gursel; Taskin, Halim

    2011-03-01

    Human body is exposed to ionising radiations both internally and externally by mainly high-energy cosmic ray particles incident on the earth's atmosphere and radioactive nuclides that originated in the earth's crust. The main objective of this study is to assess the health hazards due to environmental radiation sources in the city of Adapazari, one of the most important industrial cities of the country, Northwestern Turkey. For this purpose, natural radiation sources, external terrestrial radiations, cosmic radiations, and inhalation exposures have been investigated. The annual average external terrestrial radiation doses were determined as 0.08 and 0.35 mSv at outdoor and indoor atmospheres, respectively. The annual average cosmic radiation doses were found to be 0.08 and 0.05 mSv for directly ionising photon components and neutron components, respectively. The annual average inhalation exposure doses due to radon and thoron were obtained as 1.42 and 0.19 mSv, respectively, in the region. The annual average effective dose due to natural radiation sources was determined as a total of 2.35 mSv with the predetermined ingestion radiation dose. The lifetime cancer risk due to the background ionising radiations has been determined as 0.9×10(-2) for the residents of the Adapazari city, with the average lifespan of 70 years. The results of the effective doses due to background radiation sources in the region and the worldwide averages were discussed.

  4. Detecting a stochastic background of gravitational radiation: Signal processing strategies and sensitivities

    NASA Astrophysics Data System (ADS)

    Allen, Bruce; Romano, Joseph D.

    1999-05-01

    We analyze the signal processing required for the optimal detection of a stochastic background of gravitational radiation using laser interferometric detectors. Starting with basic assumptions about the statistical properties of a stochastic gravity-wave background, we derive expressions for the optimal filter function and signal-to-noise ratio for the cross-correlation of the outputs of two gravity-wave detectors. Sensitivity levels required for detection are then calculated. Issues related to (i) calculating the signal-to-noise ratio for arbitrarily large stochastic backgrounds, (ii) performing the data analysis in the presence of nonstationary detector noise, (iii) combining data from multiple detector pairs to increase the sensitivity of a stochastic background search, (iv) correlating the outputs of 4 or more detectors, and (v) allowing for the possibility of correlated noise in the outputs of two detectors are discussed. We briefly describe a computer simulation that was used to ``experimentally'' verify the theoretical calculations derived in the paper, and which mimics the generation and detection of a simulated stochastic gravity-wave signal in the presence of simulated detector noise. Numerous graphs and tables of numerical data for the five major interferometers (LIGO-WA, LIGO-LA, VIRGO, GEO-600, and TAMA-300) are also given. This information consists of graphs of the noise power spectra, overlap reduction functions, and optimal filter functions; also included are tables of the signal-to-noise ratios and sensitivity levels for cross-correlation measurements between different detector pairs. The treatment given in this paper should be accessible to both theorists involved in data analysis and experimentalists involved in detector design and data acquisition.

  5. 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.

  6. 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.

  7. 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.

  8. Black-body radiation in a curved Robertson-Walker background

    NASA Astrophysics Data System (ADS)

    Deng, Yaobing; Mannheim, Philip D.

    1987-07-01

    In the standard Friedmann cosmology the black-body radiation spectrum is usually taken to have the same familiar T4-form that it has in a flat space. With explicit use of the equation of motion of a quantized massless field propagating in a curved background Robertson-Walker metric the authors show (for the readily tractable scalar field case) that the assumption is in fact true for an open Universe. For a closed Universe, it is found that there is an in principle modification to the T4-law. Unfortunately, the correction turns out to be too small to be experimentally detectable. In passing, the authors also obtain a simple derivation for the cosmological red shift of frequencies.

  9. 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.

  10. Upper limits on the isotropic gravitational radiation background from pulsar timing analysis

    NASA Technical Reports Server (NTRS)

    Hellings, R. W.; Downs, G. S.

    1983-01-01

    A pulsar and the earth may be thought of as end masses of a free-mass gravitational wave antenna in which the relative motion of the masses is monitored by observing the Doppler shift of the pulse arrival times. Using timing residuals from PSR 1133 + 16, 1237 + 25, 1604-00, and 2045-16, an upper limit to the spectrum of the isotropic gravitational radiation background has been derived in the frequency band 4 x 10 to the -9th to 10 to the -7th Hz. This limit is found to be S(E) = 10 to the 21st f-cubed ergs/cu cm Hz, where S(E) is the energy density spectrum and f is the frequency in Hz. This would limit the energy density at frequencies below 10 to the -8th Hz to be 0.00014 times the critical density.

  11. New Measurements of the Cosmic Background Radiation Temperature at3.3 mm Wavelength

    SciTech Connect

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

    1986-02-01

    We have measured the temperature of the cosmic background radiation (CBR) at 3.3 mm wavelength in 1982, 1983, and 1984 as part of a larger project to determine the CBR temperature at five wavelengths from 12 cm to 3.3 mm (Smoot et al. 1985). The 3.3-mm measurements yield a brightness temperature of 2.57 K with a 1{sigma} uncertainty of 20.12 K. This paper describes the instrument, the measurement techniques, and the data-analysis procedures used. Our result is in good agreement with recent measurements at comparable wavelengths by Meyer and Jura (1985) and by Peterson, Richards, and Timusk (1985), but it disagrees with the temperatures reported by Woody and Richards (1981).

  12. 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.

  13. The excess flux in the cosmic submillimeter background radiation and the primordial deuterium abundance

    SciTech Connect

    Dermer, C.D.; Guessoum, N.; National Aeronautics and Space Administration, Greenbelt, MD . Lab. for High Energy Astrophysics)

    1989-10-27

    Recent measurements of the cosmic background radiation (CBR) show an enhanced flux in the submillimeter regime, compared to the spectrum of a 2.7 K blackbody. Thermal Comptonization of the relic radiation by a hot nonrelativistic plasma has long been known to produce distortions in the CBR spectrum, similar to what has now been observed. Heating of the primeval plasma to temperatures T {approximately} 10{sup 6} {minus} 10{sup 8} K could result from the injection of subcosmic ray protons at epoch z {approximately} 10--100. The intensity of the subcosmic ray flux that provide conditions needed to explain the submillimeter excess by thermal Comptonization also leads to the production of cosmologically significant amounts of deuterium in collisions between subcosmic ray protons and primordial protons and {alpha}-particles. However, the amount of lithium produced through {alpha}-{alpha} reactions is in conflict with the observed Li abundance. If lithium is depleted, for example, by processing through Population II stars, arguments for the baryon content of the universe based on primordial deuterium and He abundances are weakened. 12 refs., 1 fig., 1 tab.

  14. 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.

  15. Scaled Experiment to Investigate Auroral Kilometric Radiation Mechanisms in the Presence of Background Electrons

    NASA Astrophysics Data System (ADS)

    McConville, S. L.; Ronald, K.; Speirs, D. C.; Gillespie, K. M.; Phelps, A. D. R.; Cross, A. W.; Bingham, R.; Robertson, C. W.; Whyte, C. G.; He, W.; King, M.; Bryson, R.; Vorgul, I.; Cairns, R. A.; Kellett, B. J.

    2014-05-01

    Auroral Kilometric Radiation (AKR) emissions occur at frequencies ~300kHz polarised in the X-mode with efficiencies ~1-2% [1,2] in the auroral density cavity in the polar regions of the Earth's magnetosphere, a region of low density plasma ~3200km above the Earth's surface, where electrons are accelerated down towards the Earth whilst undergoing magnetic compression. As a result of this magnetic compression the electrons acquire a horseshoe distribution function in velocity space. Previous theoretical studies have predicted that this distribution is capable of driving the cyclotron maser instability. To test this theory a scaled laboratory experiment was constructed to replicate this phenomenon in a controlled environment, [3-5] whilst 2D and 3D simulations are also being conducted to predict the experimental radiation power and mode, [6-9]. The experiment operates in the microwave frequency regime and incorporates a region of increasing magnetic field as found at the Earth's pole using magnet solenoids to encase the cylindrical interaction waveguide through which an initially rectilinear electron beam (12A) was accelerated by a 75keV pulse. Experimental results showed evidence of the formation of the horseshoe distribution function. The radiation was produced in the near cut-off TE01 mode, comparable with X-mode characteristics, at 4.42GHz. Peak microwave output power was measured ~35kW and peak efficiency of emission ~2%, [3]. A Penning trap was constructed and inserted into the interaction waveguide to enable generation of a background plasma which would lead to closer comparisons with the magnetospheric conditions. Initial design and measurements are presented showing the principle features of the new geometry.

  16. 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…

  17. LSO background radiation as a transmission source using time of flight

    NASA Astrophysics Data System (ADS)

    Rothfuss, Harold; Panin, Vladimir; Moor, Andrew; Young, John; Hong, Inki; Michel, Christian; Hamill, James; Casey, Michael

    2014-09-01

    LSO scintillators (Lu2Sio5:Ce) have a background radiation which originates from the isotope Lu-176 that is present in natural occurring lutetium. The decay that occurs in this isotope is a beta decay that is in coincidence with cascade gamma emissions with energies of 307,202 and 88 keV. The coincidental nature of the beta decay with the gamma emissions allow for separation of emission data originating from a positron annihilation event from transmission type data from the Lu-176 beta decay. By using the time of flight information, and information of the chord length between two LSO pixels in coincidence as a result of a beta emission and emitted gamma, a second time window can be set to observe transmission events simultaneously to emission events. Using the time when the PET scanner is not actively acquiring positron emission data, a continuous blank can be acquired and used to reconstruct a transmission image. With this blank and the measured transmission data, a transmission image can be reconstructed. This reconstructed transmission image can be used to perform emission data corrections such as attenuation correction and scatter corrections or starting images for algorithms that estimate emission and attenuation simultaneously. It is observed that the flux of the background activity is high enough to create useful transmission images with an acquisition time of 10 min.

  18. LSO background radiation as a transmission source using time of flight.

    PubMed

    Rothfuss, Harold; Panin, Vladimir; Moor, Andrew; Young, John; Hong, Inki; Michel, Christian; Hamill, James; Casey, Michael

    2014-09-21

    LSO scintillators (Lu2Sio5:Ce) have a background radiation which originates from the isotope Lu-176 that is present in natural occurring lutetium. The decay that occurs in this isotope is a beta decay that is in coincidence with cascade gamma emissions with energies of 307,202 and 88 keV. The coincidental nature of the beta decay with the gamma emissions allow for separation of emission data originating from a positron annihilation event from transmission type data from the Lu-176 beta decay. By using the time of flight information, and information of the chord length between two LSO pixels in coincidence as a result of a beta emission and emitted gamma, a second time window can be set to observe transmission events simultaneously to emission events. Using the time when the PET scanner is not actively acquiring positron emission data, a continuous blank can be acquired and used to reconstruct a transmission image. With this blank and the measured transmission data, a transmission image can be reconstructed. This reconstructed transmission image can be used to perform emission data corrections such as attenuation correction and scatter corrections or starting images for algorithms that estimate emission and attenuation simultaneously. It is observed that the flux of the background activity is high enough to create useful transmission images with an acquisition time of 10 min.

  19. An Analysis of Recent Measurements of the Temperature of theCosmic Microwave Background Radiation

    SciTech Connect

    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 cm are well fit by a blackbody spectrum at 2.74 {+-} 0.02 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 {+-} 0.002 and temperature 2.823 {+-} 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.

  20. 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.

  1. Effects of Reduced Natural Background Radiation on Drosophila melanogaster Growth and Development as Revealed by the FLYINGLOW Program.

    PubMed

    Morciano, P; Iorio, R; Iovino, D; Cipressa, F; Esposito, G; Porrazzo, A; Satta, L; Alesse, E; Tabocchini, M A; Cenci, G

    2017-03-06

    Natural background radiation of Earth and cosmic rays played a relevant role during the evolution of living organisms. However, how chronic low doses of radiation can affect biological processes is still unclear. Previous data have indicated that cells grown at the Gran Sasso Underground Laboratory (LNGS, L'Aquila) of National Institute of Nuclear Physics (INFN) of Italy, where the dose rate of cosmic rays and neutrons is significantly reduced with respect to the external environment, elicited an impaired response against endogenous damage as compared to cells grown outside LNGS. This suggests that environmental radiation contributes to the development of defense mechanisms at cellular level. To further understand how environmental radiation affects metabolism of living organisms, we have recently launched the FLYINGLOW program that aims at exploiting Drosophila melanogaster as a model for evaluating the effects of low doses/dose rates of radiation at the organismal level. Here, we will present a comparative data set on lifespan, motility and fertility from different Drosophila strains grown in parallel at LNGS and in a reference laboratory at the University of L'Aquila. Our data suggest the reduced radiation environment can influence Drosophila development and, depending on the genetic background, may affect viability for several generations even when flies are moved back to normal background radiation. As flies are considered a valuable model for human biology, our results might shed some light on understanding the effect of low dose radiation also in humans. This article is protected by copyright. All rights reserved.

  2. The high energy gamma-ray background and the interstellar radiation field

    NASA Astrophysics Data System (ADS)

    Chary, Ranga-Ram

    This thesis provides an independent estimate of the high latitude (! b! > 20°) contribution to the E > 30 MeV gamma-ray background from Galactic nucleon-nucleon, electron bremsstrahlung and inverse Compton processes. In particular, the inverse Compton contribution has been estimated for different cosmic ray electron distributions and after factoring in the anisotropy in the interstellar radiation field and the anisotropic Klein-Nishina scattering cross section. A model for the interstellar radiation field from 0.1 μm to 1000 μm is also presented to fit the intensities observed by recent satellite experiments, especially the DIRBE and FIRAS instruments on COBE. I find that the emission from the inverse Compton process when the anisotropy in the radiation field is included can be higher by up to 50% when compared to estimates that adopt an isotropic radiation field. Simulated inverse Compton maps with a cosmic ray electron distribution represented by a ``pill box'' extending up to a distance of 5 kpc above the Galactic plane provide better fits to the EGRET intensity maps suggesting that the cosmic ray halo may be larger than previously thought. With this distribution, I find that the net contribution from the IC process to the gamma-ray background can be as high as 20% at high Galactic latitudes. Fitting for the Galactic components of gamma-ray emission confirms the existence of an isotropic component with an intensity that can be represented by the form 27.7 × E(MeV)-2.16 photons m-2 s-1 sr -1 MeV-1, in excellent agreement with previous estimates. The spectrum of the isotropic component further argues strongly in favor of unresolved gamma-ray blazars being the source of this emission. Introduction of an anisotropic component improves the quality of the fits. However, this component, which could potentially arise from the dark matter in the Galactic halo, is not well characterized by a single power law which might be associated with any single dark matter

  3. 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.

  4. High background radiation investigated by gamma spectrometry of the soil in the southwestern region of Cameroon.

    PubMed

    Ele Abiama, P; Owono Ateba, P; Ben-Bolie, G H; Ekobena, F H P; El Khoukhi, T

    2010-09-01

    The aim of this work is to determine the radioactivity concentration of (226)Ra, (232)Th and (40)K in sub-surface (0-5 cm) soil samples collected from Awanda, Bikoué, Ngombas in the southwestern region of Cameroon, to assess their contribution to the external dose exposure relative to the United Nation Scientific Committee on Effects of Atomic Radiation (UNSCEAR) data. An HPGe p-type detector coupled to a multichannel analyzer was used to perform measurements and data processing. The activity concentrations of (226)Ra varied from 0.06+/-0.01 to 0.27+/-0.02 kBq kg(-1) with a mean value of 0.13+/-0.01 kBq kg(-1) wet weight. The activity concentrations of (232)Th varied from 0.10+/-0.01 to 0.70+/-0.05 kBq kg(-1) with a mean value of 0.39+/-0.03 kBq kg(-1) wet weight, and (40)K concentrations varied from 0.37+/-0.02 to 1.53+/-0.11 kBq kg(-1) with a mean value of 0.85+/-0.07 kBq kg(-1) wet weight, respectively. The mean value of outdoor annual effective doses were estimated to be 0.48 mSv y(-1), 0.39 mSv y(-1) and 0.38 mSv y(-1) from Ngombas, Awanda and Bikoué, respectively. The studied areas can be said to have a high background radiation level.

  5. 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

  6. 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.

  7. Measurement of the large-scale anisotropy of the cosmic background radiation at 3 MM

    NASA Astrophysics Data System (ADS)

    Epstein, G. L.

    A balloon-borne differential radiometer has measured the large-scale anisotropy of the cosmic background radiation (CBR) with high sensitivity. The antenna temperature dipole anisotropy at 90 GHz (3mm wavelength) is 2.82 + or - 0.19 mK, corresponding to a thermodynamic anisotropy of 3.48 + or - 0.24 mK for a 2.7 K blackbody CBR. Since the magnitude of the dipole anisotropy induced by motion through the CBR depends on both the CBR intensity and its spectral index, anisotropy measurements at several frequencies provide information about the CBR spectrum. The ratio of the dipole magnitudes measured at 90 GHz by this experiment and at 24.5 GHz by another recent observation is consistent with a 2.7 K blackbody CBR but does not require such a spectrum. If the CBR spectrum is blackbody, the two measurements establish a 90% confidence-level lower limit of 2.2 K on its temperature.

  8. 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.

  9. Reconstructing single-field inflationary actions from cosmic microwave background radiation data

    SciTech Connect

    Gauthier, Christopher S; Akhoury, Ratindranath E-mail: akhoury@umich.edu

    2008-07-15

    This paper describes a general program for deriving the action of single-field inflation models with non-standard kinetic energy terms using cosmic microwave background radiation power spectrum data. This method assumes that an action depends on a set of undetermined functions, each of which is a function of either the inflaton wavefunction or its time derivative. The scalar, tensor and non-Gaussianity of the curvature perturbation spectrum are used to derive a set of reconstruction equations whose solution set can specify up to three of the undetermined functions. The method is then used to find the undetermined functions in various types of action assuming power law type scalar and tensor spectra. In actions that contain only two unknown functions, the third reconstruction equation implies a consistency relation between the non-Gaussianity, sound speed and slow roll parameters. In particular we focus on reconstructing a generalized Dirac-Born-Infeld action with an unknown potential and warp factor. We find that for realistic scalar and tensor spectra, the reconstructed warp factor and potential are very similar to the theoretically derived result. Furthermore, physical consistency of the reconstructed warp factor and potential imposes strict constraints on the scalar and tensor spectral indices.

  10. 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.

  11. Does shared family background influence the impact of educational differences on early mortality?

    PubMed

    Søndergaard, Grethe; Mortensen, Laust H; Nybo Andersen, Anne-Marie; Andersen, Per Kragh; Dalton, Susanne Oksbjerg; Madsen, Mia; Osler, Merete

    2012-10-15

    The mechanisms behind social differences in mortality rates have been debated. The authors examined the extent to which shared family background and health in early life could explain the association between educational status and all-cause mortality rates using a sibling design. The study was register-based and included all individuals born in Denmark between 1950 and 1979 who had at least 1 full sibling born in the same time period (n = 1,381,436). All individuals were followed from 28 years of age until death, emigration, or December 2009. The authors used Cox regression analyses to estimate hazard ratios for mortality according to educational level. Conventional cohort and intersibling analyses were carried out and conducted separately for deaths occurring before and after the age of 45 years, respectively. The cohort analyses showed an inverse association between educational status and all-cause mortality that was strongest for males, increased with younger birth cohorts, and tended to be strongest in the analyses of death before 45 years of age. The associations were attenuated slightly in the intersibling analyses and after adjustment for serious health conditions in early life. Hence, health selection and confounding by factors shared by siblings explained only a minor part of the association between educational level and all-cause mortality.

  12. 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.

  13. Changing universe model of the cosmic microwave background, early type galaxies, redshift, and discrete redshifts

    NASA Astrophysics Data System (ADS)

    Hodge, John

    2005-04-01

    Developing the changing universe model (CUM) toward an alternate cosmological model provides motivation to investigate cosmological observations. The black body nature of the CMB is consistent with the CUM. Since the CUM posits the photons are quantized, positing quantum oscillators in the wall of the black body cavity is unnecessary. The CMB temperature and mass content of our universe is controlled by a feedback mechanism. If our universe is stable, the temperature of the CMB radiation should be 2.718 K. The CUM suggests the higher measured CMB temperature indicates an imbalance between energy injection and energy ejection rates of the Sources and Sinks. Several differences among galaxy types suggest that spiral galaxies are Sources and that early type and irregular galaxies are Sinks. The redshift calculation explored previously (SESAPS '04,session GD 15) is improved. Further, the CUM suggests the discrete variations in redshift, reported by W. G. Tifft, 1997, Astrophy. J. 485, 465 (and references therein) and confirmed by others, are consistent with the Sink's effect on redshift in clusters. Full text: http://web.infoave.net/ scjh.

  14. 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.

  15. 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.

  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. Federal Guidance Report No. 2: Background Material for the Development of Radiation Protection Standards (Federal Radiation Council)

    EPA Pesticide Factsheets

    This report discusses how to provide guidance for Federal agencies in activities designed to limit exposure of members of population groups to radiation from radioactive materials deposited in the body as a result of their occurrence in the environment.

  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. Background radiation, electrical work, and some other exposures associated with acute myeloid leukemia in a case-referent study.

    PubMed

    Flodin, U; Fredriksson, M; Persson, B; Hardell, L; Axelson, O

    1986-01-01

    The effect of potential risk factors for acute myeloid leukemia was evaluated in a case-referent study encompassing 59 cases and 354 referents, all of whom were alive. Information on exposure was obtained through a questionnaire mailed to the subjects. The possible effect of background radiation was evaluated by means of a gamma radiation index, which accounted for the differences between cases and referents in this respect, i.e., in time spent in concrete buildings both at home and at work places. In the 20-54 yr old age group, there was an association between leukemia morbidity and index of background radiation. X-ray treatment and electrical work were also associated with increased rate ratios. With regard to solvents, only styrene appeared as a risk factor, but the number of exposed subjects was small. Other exposures were less clearly associated with increased risks.

  20. 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.

  1. Large scale anisotropy of the 3K cosmic background radiation at 24.8, 31.4 and 46.0 GHZ

    NASA Astrophysics Data System (ADS)

    Cheng, E. S.

    The 3K cosmic background radiation (CBR), believed to be the signature of the initial singularity in "big bang" cosmologies, is a fundamental tool for understanding the structure of the early universe. We describe here a measurement of the spatial anisotropy of this radiation at a sensitivity of 6 parts in 10 to the 5th. The observations were carried out in a balloon-borne package using three room temperature, correlation-type microwave radiometers, with 500 MHz bandwidths centered at 24,8,31.4 and 46.0 GHz. The achieved system noise temperatures for the three receivers is 800K. Three flights between August 1978 and July 1980 cover the entire Northern Hemisphere sky, allowing for tests of both dipole and higher order anisotropies.

  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. 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

  4. 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.

  5. Triassic origin and early radiation of multicellular volvocine algae.

    PubMed

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

    2009-03-03

    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.

  6. 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.

  7. Effects of early visual experience on the background preference in juvenile cuttlefish Sepia pharaonis.

    PubMed

    Lee, Yi-Hsin; Yan, Hong Young; Chiao, Chuan-Chin

    2012-10-23

    Although cuttlefish are capable of showing diverse camouflage body patterns against a variety of background substrates, whether they show background preference when given a choice of substrates is not well known. In this study, we characterized the background choice of post-embryonic cuttlefish (Sepia pharaonis) and examined the effects of rearing visual environments on their background preferences. Different rearing backgrounds (enriched, uniformly grey and checkerboard) were used to raise cuttlefish from eggs or hatchlings, and four sets of two-background-choice experiments (differences in contrast, shape, size and side) were conducted at day 1 and weeks 4, 8 and 12 post-hatch. Cuttlefish reared in the enriched environment preferred high-contrast backgrounds at all post-embryonic stages. In comparison, those reared in the impoverished environments (uniformly grey and checkerboard) had either reversed or delayed high-contrast background preference. In addition, cuttlefish raised on the uniformly grey background, exposed to a checkerboard briefly (0.5 or 3 h) at week 4 and tested at week 8 showed increased high-contrast background preference. Interestingly, cuttlefish in the enriched group preferred an object size similar to their body size at day 1 and week 4, but changed this preference to smaller objects at week 12. These results suggest that high-contrast backgrounds may be more adaptive for juvenile cuttlefish, and visually enriched environments are important for the development of these background preference behaviours.

  8. 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.

  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. 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.

  11. Hybrid radiation background monitoring in operational control and forecasting of environmental contamination by nuclear power station discharges

    SciTech Connect

    Ermeev, I.S.; Eremenko, V.A.; Makarov, Y.A.; Matueev, V.V.; Zhernov, V.S.

    1986-05-01

    Rapid developments in nuclear power have stimulated research on monitoring and forecasting environmental radiation pollution (ERP), and in particular the amounts, compositions, and distributions of radionuclides in the environment. A conceptual model is presented for hybrid environmental radiation pollution monitoring. When there is an emergency, the model operates in a fashion most closely corresponding to the actual meteorological conditions, and the ERP data given by the model enable one to distinguish changes due to the man-made component from random fluctuations in the natural background. The measurement system in general includes mobile and stationary data-acquisition facilities linked by wire or radio to the central point. The system also accumulates and stores data on the radiation environment, which are edited on the basis of radioactive, chemical, and other transformations. The purpose of hybrid monitoring is ultimately to analyze trends in order to detect elevated discharges and thus to output data to the regional monitoring system.

  12. On unitary evolution of a massless scalar field in a Schwarzschild background: Hawking radiation and the information paradox

    SciTech Connect

    Melnikov, Kirill

    2002-08-08

    We develop a Hamiltonian formalism which can be used to discuss the physics of a massless scalar field in a gravitational background of a Schwarzschild black hole. Using this formalism we show that the time evolution of the system is unitary and yet all known results such as the existence of Hawking radiation can be readily understood. We then point out that the Hamiltonian formalism leads to interesting observations about black hole entropy and the information paradox.

  13. 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.

  14. An overview of the Cosmic Background Explorer (COBE) and its observations - New sky maps of the early universe

    NASA Technical Reports Server (NTRS)

    Smoot, George F.

    1992-01-01

    This paper discusses the three instruments aboard NASA's Cosmic Background Explorer (COBE) satellite and presents early results obtained from the first six months of observations. The three instruments (FIRAS, DMR, and DIRBE) have operated well and produced significant new results. The FIRAS measurement of the CMB spectrum supports the standard Big Bang model. The maps made from the DMR instrument measurements show a spatially smooth early universe. The maps of galactic and zodiacal emission produced by the DIRBE instrument are needed to identify the foreground emissions from extragalactic and thus to interpret its and the other COBE results in terms of events in the early universe.

  15. Simulation of Radiation Backgrounds associated with the HEXRI Diagnostics at the National Ignition Facility

    SciTech Connect

    Khater, H; Dauffy, L; Tommasini, R; Eckart, M; Eder, D

    2009-10-05

    Experiments resulting in a significant neutron yield are scheduled to start in 2010 at the National Ignition Facility (NIF). A wide range of diagnostics will be used to measure several parameters of implosion such as the core and fuel shape, temperatures and densities, and neutron yield. Accurate evaluations of the neutron and gamma backgrounds are important for several diagnostics, such as the High Energy X-ray Imager (HEXRI). Several Monte-Carlo simulations were performed to identify the expected signal to background ratios at several potential locations for the HEXRI diagnostics. Gamma backgrounds were significantly reduced by using tungsten collimators. The collimators resulted in the reduction of the gamma background at the HEXRI scintillators by more than an order of magnitude during the first 40 ns following a THD shot.

  16. Federal Guidance Report No. 5: Background Material for the Development of Radiation Protection Standards

    EPA Pesticide Factsheets

    This report contains background material used in the development of guidance for Federal agencies in respect to planning protective actions to reduce potential doses from radioactive fission products to the population.

  17. 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.

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

    DOE PAGES

    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

  20. 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.

  1. 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…

  2. 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…

  3. Genetic background of enhanced radioresistance in an anhydrobiotic insect: transcriptional response to ionizing radiations and desiccation.

    PubMed

    Ryabova, Alina; Mukae, Kyosuke; Cherkasov, Alexander; Cornette, Richard; Shagimardanova, Elena; Sakashita, Tetsuya; Okuda, Takashi; Kikawada, Takahiro; Gusev, Oleg

    2017-01-01

    It is assumed that resistance to ionizing radiation, as well as cross-resistance to other abiotic stresses, is a side effect of the evolutionary-based adaptation of anhydrobiotic animals to dehydration stress. Larvae of Polypedilum vanderplanki can withstand prolonged desiccation as well as high doses of ionizing radiation exposure. For a further understanding of the mechanisms of cross-tolerance to both types of stress exposure, we profiled genome-wide mRNA expression patterns using microarray techniques on the chironomid larvae collected at different stages of desiccation and after exposure to two types of ionizing radiation-70 Gy of high-linear energy transfer (LET) ions ((4)He) and the same dose of low-LET radiation (gamma rays). In expression profiles, a wide transcriptional response to desiccation stress that much exceeded the amount of up-regulated transcripts to irradiation exposure was observed. An extensive group of coincidently up-regulated overlapped transcripts in response to desiccation and ionizing radiation was found. Among this, overlapped set of transcripts was indicated anhydrobiosis-related genes: antioxidants, late embryogenesis abundant (LEA) proteins, and heat-shock proteins. The most overexpressed group was that of protein-L-isoaspartate/D-aspartate O-methyltransferase (PIMT), while probes, corresponding to LEA proteins, were the most represented. Performed functional analysis showed strongly enriched gene ontology terms associated with protein methylation. In addition, active processes of DNA repair were detected. We assume that the cross-tolerance of the sleeping chironomid to both desiccation and irradiation exposure comes from a complex mechanism of adaptation to anhydrobiosis.

  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.

  5. 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.

  6. Early mechanisms in radiation-induced biological damage

    SciTech Connect

    Powers, E.L.

    1983-01-01

    An introduction to the mechanisms of radiation action in biological systems is presented. Several questions about the nature of the radiation damage process are discussed, including recognition of the oxygen effects, dose-response relationships, and the importance of the hydroxyl radical. (ACR)

  7. Methods for assessing background levels of radiation and radioactive materials in the environment around uranium mills

    SciTech Connect

    Wogman, N.A.; Silker, W.B.; Glissmeyer, J.A.; Endres, G.W.R.

    1980-04-01

    Techniques and costs for determining background levels and mill contributions to the environment are assessed. Three specific programs are identified for the determination of natural background and mill contributions to that background. Since the most significant radiological impact to man within 10 km of mill tailings occurs through airborne /sup 222/Rn and its daughters, their measurement is emphasized in the suggested procedures. The next major radiological impact from the mills occurs through airborne movement of particulates from the mill and its tailings piles. Thus, the more sophisticated measurement technologies presented include measurements of airborne radionuclide particulates, as well as methods to measure the dose from /sup 222/Rn and its daughters. The most expensive methods for assessing background levels of radioactive materials around uranium mills allow a determination of uranium, thorium, and radium in water, soil, and vegetation, as well as air. The methodologies are organized by their increasing capital and operating costs. The more expensive techniques provide a better evaluation of the mill contribution to the environment. There is no single universal technique that is applicable to all mills.

  8. 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.

  9. Studies of Background Levels for the NIF Yield Diagnostics from Neutron and Gamma Radiation

    SciTech Connect

    Song, P; Eder, D; Moran, M; Landen, O; O'Brien, D; Hsing, W

    2007-08-27

    The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) is nearing completion of construction and is preparing for the National Ignition Campaign (NIC) with potentially significant yield in 2010. The design of a wide range of yield diagnostics in and outside the target-bay of the NIF must consider scattered background neutrons and neutron-induced gamma rays to measure neutrons and x-rays from target. The large and complex target chamber and facility make the calculation of scattered neutrons and gamma rays extremely challenging. The NIF was designed with shielded locations for many of the yield diagnostics including the neutron alcove and four diagnostic mezzanines. Accurate calculation of the background levels in these shielded locations requires advanced Monte Carlo techniques, e.g., variance reduction. Placement, size, and materials of collimators on the line of sight (LOS) through the shielding must be evaluated to trade off signal levels and unwanted backgrounds. The background at these locations is also affected by neutrons that pass through the laser beam tubes and scatter off of structures and walls in the switch yards. Detailed 3D Monte Carlo analyses are performed to determine neutron and gamma fluxes for some of the yield diagnostics.

  10. 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

  11. 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

  12. 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.

  13. 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.

  14. A balloon borne maser measurement of the anisotropy of the cosmic background radiation

    NASA Astrophysics Data System (ADS)

    Fixsen, D. J.

    A 24.6 GHz maser served as a low noise front end amplifier for the radiometer. The system noise temperature was 33 K and the bandwidth was 300 MHz. Effects of low frequency drifts were reduced by switching between two horns and by rotating the gondola. A model of galactic radiation was subtracted from the antenna temperature distribution, and the remainder was fit to dipole and quadrupole distributions. The parameters obtained for the dipole distribution are: Tx = 2.9 + or - .13 Ty = .84 + or - .07, Tz = .40 + or - .06 mK antenna temperature, in celestial coordinates. No significant quadrupole was found, but an upper limit of .13 mK was placed on the rms value of a quadrupole distribution. The results are consistent with a model in which the sun is moving 353 + or - 15 km/s towards 11.0 + or - .15 hours right ascension, -7 deg + or - 2 deg declination, in uniform 2.7 K blackbody radiation.

  15. TeV gamma rays from the blazar H 1426+428 and the diffuse extragalactic background radiation

    NASA Astrophysics Data System (ADS)

    Aharonian, F.; Akhperjanian, A.; Barrio, J.; Beilicke, M.; Bernlöhr, K.; Börst, H.; Bojahr, H.; Bolz, O.; Contreras, J.; Cornils, R.; Cortina, J.; Denninghoff, S.; Fonseca, V.; Girma, M.; Gonzalez, J.; Götting, N.; Heinzelmann, G.; Hermann, G.; Heusler, A.; Hofmann, W.; Horns, D.; Jung, I.; Kankanyan, R.; Kestel, M.; Kettler, J.; Kohnle, A.; Konopelko, A.; Kornmeyer, H.; Kranich, D.; Krawczynski, H.; Lampeitl, H.; Lopez, M.; Lorenz, E.; Lucarelli, F.; Magnussen, N.; Mang, O.; Meyer, H.; Mirzoyan, R.; Moralejo, A.; Ona, E.; Padilla, L.; Panter, M.; Plaga, R.; Plyasheshnikov, A.; Pühlhofer, G.; Rauterberg, G.; Röhring, A.; Rhode, W.; Robrade, J.; Rowell, G.; Sahakian, V.; Samorski, M.; Schilling, M.; Schröder, F.; Sevilla, I.; Siems, M.; Stamm, W.; Tluczykont, M.; Völk, H. J.; Wiedner, C. A.; Wittek, W.

    2002-03-01

    The detection of TeV gamma -rays from the blazar H 1426+428 at an integral flux level of (4 +/- 2stat +/- 1syst) x 10-12 erg cm-2 s-1 above 1 TeV with the HEGRA imaging atmospheric Cherenkov telescope system is reported. H 1426+428 is located at a redshift of z = 0.129, which makes it the most distant source detected in TeV gamma -rays so far. The TeV radiation is expected to be strongly absorbed by the diffuse extragalactic background radiation (DEBRA). The observed energy spectrum of TeV photons is in good agreement with an intrinsic power law spectrum of the source ~ E-1.9 corrected for DEBRA absorption. Statistical errors as well as uncertainties about the intrinsic source spectrum, however, do not permit strong statements about the density of the DEBRA infrared photon field.

  16. The cosmic neutrino background

    NASA Technical Reports Server (NTRS)

    Dar, Arnon

    1991-01-01

    The cosmic neutrino background is expected to consist of relic neutrinos from the big bang, of neutrinos produced during nuclear burning in stars, of neutrinos released by gravitational stellar collapse, and of neutrinos produced by cosmic ray interactions with matter and radiation in the interstellar and intergalactic medium. Formation of baryonic dark matter in the early universe, matter-antimatter annihilation in a baryonic symmetric universe, and dark matter annihilation could have also contributed significantly to the cosmic neutrino background. The purpose of this paper is to review the properties of these cosmic neutrino backgrounds, the indirect evidence for their existence, and the prospects for their detection.

  17. 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 future hard X-ray all sky satellites achieve a sensitivity better than 10–12 erg cm–2 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.

  18. 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.

  19. 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…

  20. Early Childhood Development and Social Integration: The Mediterranean Experience. A Background Paper.

    ERIC Educational Resources Information Center

    van Oudenhoven, Nico; Wazir, Rekha

    This paper explores early childhood education (ECD) and social integration within a common framework and against the backdrop of experience gained in these fields in the following 12 Mediterranean nations: Algeria, Cyprus, Egypt, Israel, Jordan, Lebanon, Malta, Morocco, Palestine, Syrian Arab Republic, Tunisia, and Turkey. The paper notes that…

  1. Re-Examining the Associations between Family Backgrounds and Children's Cognitive Developments in Early Ages

    ERIC Educational Resources Information Center

    Tu, Yu-Kang; Law, Graham R.

    2010-01-01

    A recent English study found that children from poor families who did well in cognitive tests at age three are expected to be overtaken in the cognitive test by the age of seven by children from rich families who did poorly in cognitive tests at age three. The conclusion was that family background seems to have a dominant influence on a child's…

  2. 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,"…

  3. Learning in Complex Environments: The Effects of Background Speech on Early Word Learning

    ERIC Educational Resources Information Center

    McMillan, Brianna T. M.; Saffran, Jenny R.

    2016-01-01

    Although most studies of language learning take place in quiet laboratory settings, everyday language learning occurs under noisy conditions. The current research investigated the effects of background speech on word learning. Both younger (22- to 24-month-olds; n = 40) and older (28- to 30-month-olds; n = 40) toddlers successfully learned novel…

  4. 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.

  5. Consequences of a possible violation of the Strong Equivalence Principle. I. Statistical Physics, Thermodynamics and the Background Radiation

    NASA Astrophysics Data System (ADS)

    Serna, A.

    1996-06-01

    We analyze the consequences of a possible (scale-covariant) violation of the Strong Equivalence Principle on the basic expressions of statistical physics and thermodynamics. To this end, we use the kinetic theory generalized to a Weyl geometry, developed by Dominguez-Tenreiro and Serna (1990). We find that, although the entropy per particle is constant, the universe expansion is not adiabatic in this framework. However, it is possible to define a quantity with dimensions of entropy that is, instead, conserevd during the universe expansion. We also show that the obtained generalized equations are compatible with some observational results as, for example, the cosmic background radiation

  6. 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.

  7. Time Domain Analysis of ARIANNA Data Acquisition: Distinguishing Askaryan Radiation from Thermal Backgrounds

    NASA Astrophysics Data System (ADS)

    Hanson, Jordan

    2014-03-01

    The Antarctica Ross Ice Shelf Antenna Neutrino Array (ARIANNA) is a high energy astrophysical neutrino detector, currently under construction near McMurdo Station, Antarctica. The ARIANNA detector design is optimized for detection of Askaryan radio frequency pulses, created in the ice shelf above the Antarctic ocean, that originate from cosmogenic GZK neutrino interactions. A formal analysis of the electromagnetic properties of the ARIANNA detection chain in the time domain is presented, and combined with a theoretical understanding of the Askaryan signal. This combination produces signal templates, used to distinguish thermal backgrounds from true signal in the current ARIANNA data. The results of this data analysis are also presented.

  8. Entanglement of particles as a result of their coupling through the common background zero-point radiation field

    NASA Astrophysics Data System (ADS)

    de la Peña, L.; Valdés-Hernández, A.; Cetto, A. M.

    2010-01-01

    This paper is intended to disclose a possible physical mechanism underlying entanglement, by allowing an (otherwise classical) system of two non-interacting particles to interact with the stochastic background zero-point radiation field. The present analysis is made in the framework of linear stochastic electrodynamics (LSED), a theory that has been shown to recover the corresponding matrix formulation of quantum mechanics when applied to a one-particle (or atomic) system. We start by briefly recalling the basic elements of LSED and then extend the theory to consider the system formed of two particles. It is found that when both particles resonate to at least one common frequency of the background field, a new class of non-factorizable states emerge that correspond just to the entangled states of quantum mechanics. In the particular case of two equal particles the ensuing states are those of maximum entanglement.

  9. 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.

  10. Reduction of radioactive backgrounds in electroformed copper for ultra-sensitive radiation detectors

    NASA Astrophysics Data System (ADS)

    Hoppe, E. W.; Aalseth, C. E.; Farmer, O. T.; Hossbach, T. W.; Liezers, M.; Miley, H. S.; Overman, N. R.; Reeves, J. H.

    2014-11-01

    Ultra-pure construction materials are required for the next generation of neutrino physics, dark matter and environmental science applications. These materials are also important for use in high-purity germanium spectrometers used in screening materials for radiopurity. The next-generation science applications require materials with radiopurity levels at or below 1 μBq/kg 232Th and 238U. Yet radiometric analysis lacks sensitivity below 10 μBq/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 a μBq/kg level 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.

  11. A common genetic background could explain early-onset Crohn's disease.

    PubMed

    Bianco, Anna Monica; Zanin, Valentina; Girardelli, Martina; Magnolato, Andrea; Martelossi, Stefano; Martellossi, Stefano; Tommasini, Alberto; Marcuzzi, Annalisa; Crovella, Sergio

    2012-04-01

    Crohn's disease (CD) is a multifactorial disease, in which environmental, microbial and genetic factors play important roles. CD is characterized by a chronic granulomatous inflammation by necrotic scarring with aspects of full-thickness wall. In spite of affecting mainly young adults, sometimes, CD can be present in the first year of life (early onset Crohn disease, EOCD) showing an unpredictable course and being often more severe than at older ages. In this paper we propose the hypothesis that EOCD patients should be analyzed using a Mendelian approach with family studies aimed to identify new loci directly involved in the early onset Crohn's disease. So we will leave the classic association study approach used until now for the identification of genes responsible for susceptibility to CD and propose linkage family analysis as alternative and powerful tool for the identification of new genetic variants associated with familiar cases of EOCD.

  12. Information geometry with correlated data: Bayesian explorations of cosmological predictions for the microwave background radiation

    NASA Astrophysics Data System (ADS)

    Quinn, Katherine; de Bernardis, Francesco; Niemack, Michael; Sethna, James

    We developed a new, generalized fitting algorithm for miltiparameter models which incorporates varying and correlated errors. This was combined with geometrical methods of sampling to explore model prediction space, notably to plot geodesics and determine the size and edges of the model manifold. We illustrate this using the microwave background spectra for all possible universes, as described by the standard Λ-cold dark matter (Λ-CDM) cosmological model. In this case, the predicted data are fluctuations and highly correlated with varying errors, resulting in a manifold with a varying metric (as the natural metric to use is given by the Fisher information matrix). Furthermore, the model manifold shares the hyperribbon structure seen in other models, with the edges forming a strongly distorted image of a hypercube. Practical applications of such an analysis include optimizing experimental instrumentation designed to test more detailed cosmological theories. Funding supported in part by NSERC.

  13. 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.

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

    PubMed

    Clifton, Timothy; Clarkson, Chris; Bull, Philip

    2012-08-03

    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.

  15. 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.

  16. Measurements of the anisotropy of the cosmic background radiation and diffuse galactic emission at millimeter and submillimeter wavelengths

    NASA Astrophysics Data System (ADS)

    Halpern, Mark; Benford, Richard; Meyer, Stephan; Muehlner, Dirk; Weiss, Rainer

    1988-09-01

    The authors report the results of a balloon-borne observing program to measure the large angular scale brightness distribution of the 2.7K cosmic background radiation (CBR) at millimeter and submillimeter wavelengths. It is found that the dipole moment anisotropy of the cosmic background radiation has the spectrum expected of a Doppler-shifted blackbody out to 3 times the frequency of peak intensity. A reliable estimate of the brightness of the dipole moment is obtained by averaging the best modern data under the assumption that the CBR has a Planckian spectrum with TCBR= 2.74K. The result is that ΔTdipole= 3.29±0.11 mK corresponding to a velocity of 360±12 km s-1 towards R.A. = 11h.13±0h.04, δ = -7°.7±0°.55. The present data are not consistent with a reported short-wavelength rise in the brightness of the CBR. Diffuse Galactic emission is seen to have a complicated spectrum and its shape depends on the wavelength of observation. The authors have found an extended source which runs parallel to the Galactic plane at b = 20° from l = 40° to l = 110° with a brightness of 3mK. Observations and upper limits at various frequencies are consistent with this source being a thermal emitter at a temperature of 6K.

  17. The interaction of natural background gamma radiation with depleted uranium micro-particles in the human body.

    PubMed

    Pattison, John E

    2013-03-01

    In this study, some characteristics of the photo-electrons produced when natural background gamma radiation interacts with micron-sized depleted uranium (DU) particles in the human body have been estimated using Monte Carlo simulations. In addition, an estimate has been made of the likelihood of radiological health effects occurring due to such an exposure. Upon exposure to naturally occurring background gamma radiation, DU particles in the body will produce an enhancement of the dose to the tissue in the immediate vicinity of the particles due to the photo-electric absorption of the radiation in the particle. In this study, the photo-electrons produced by a 10 μm-size particle embedded in tissue at the centre of the human torso have been investigated. The mean energies of the photo-electrons in the DU particle and in the two consecutive immediately surrounding 2 μm-wide tissue shells around the particle were found to be 38, 49 and 50 keV, respectively, with corresponding ranges of 1.3, 38 and 39 μm, respectively. The total photo-electron fluence-rates in the two consecutive 2 μm-wide tissue layers were found to be 14% and 7% of the fluence-rate in the DU particle, respectively. The estimated dose enhancement due to one 10 μm-sized DU particle in 1 cm(3) of tissue was less than 2 in 10 million of the dose received by the tissue without a particle being present. The increase in risk of death from cancer due to this effect is consequently insignificant.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. Early active sun - Radiation history of distinct components in fines

    NASA Technical Reports Server (NTRS)

    Crozaz, G.; Taylor, G. J.; Walker, R. M.; Seitz, M. G.

    1974-01-01

    Plagioclase feldspars were separated from lunar soil samples and their compositions were determined by electron-microprobe analysis followed by etching and track counting in an effort to find effects of early solar activity. The feldspars were assigned on this basis to three major lithologies: mare basalts, anorthositic rocks, and KREEP rock. The results are in sharp contrast to Poupeau et al.'s (1973) observations on track densities in plagioclase crystals in the Luna 16 soil: no evidence is found for an early active sun, although the evidence does not preclude this possibility, either.

  3. Hypofractionated radiation therapy in the treatment of early-stage breast cancer.

    PubMed

    Freedman, Gary M

    2012-02-01

    Hypofractionated radiation refers to the use of fewer, larger-dose radiation treatments that are usually given over a shorter time period compared to conventional radiation fraction sizes. Randomized trials of hypofractionated whole breast irradiation (WBI) have demonstrated comparable outcomes as conventional fractionation. For a higher-risk population for local recurrence, a phase 3 trial by the Radiation Therapy Oncology Group (RTOG) is currently studying hypofractionated WBI with a concurrent tumor bed boost over 3 weeks. Accelerated partial breast irradiation limits radiation to the region of the tumor bed for 1-3 weeks and is the subject of an ongoing randomized trial by the National Surgical Breast and Bowel Project and RTOG. Questions remain for hypofractionation about optimal patient selection, radiation techniques, and the risk of late toxicity. But results from current trials could make hypofractionation more widely accepted for patients with early-stage breast cancer.

  4. 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.

  5. 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.

  6. 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.

  7. Hierarchical Bayesian detection algorithm for early-universe relics in the cosmic microwave background

    NASA Astrophysics Data System (ADS)

    Feeney, Stephen M.; Johnson, Matthew C.; McEwen, Jason D.; Mortlock, Daniel J.; Peiris, Hiranya V.

    2013-08-01

    A number of theoretically well-motivated additions to the standard cosmological model predict weak signatures in the form of spatially localized sources embedded in the cosmic microwave background (CMB) fluctuations. We present a hierarchical Bayesian statistical formalism and a complete data analysis pipeline for testing such scenarios. We derive an accurate approximation to the full posterior probability distribution over the parameters defining any theory that predicts sources embedded in the CMB, and perform an extensive set of tests in order to establish its validity. The approximation is implemented using a modular algorithm, designed to avoid a posteriori selection effects, which combines a candidate-detection stage with a full Bayesian model-selection and parameter-estimation analysis. We apply this pipeline to theories that predict cosmic textures and bubble collisions, extending previous analyses by using: (1) adaptive-resolution techniques, allowing us to probe features of arbitrary size, and (2) optimal filters, which provide the best possible sensitivity for detecting candidate signatures. We conclude that the WMAP 7-year data do not favor the addition of either cosmic textures or bubble collisions to ΛCDM, and place robust constraints on the predicted number of such sources. The expected numbers of bubble collisions and cosmic textures on the CMB sky within our detection thresholds are constrained to be fewer than 4.0 and 5.2 at 95% confidence, respectively.

  8. 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.

  9. Urinary metabolic signatures and early triage of acute radiation exposure in rat model.

    PubMed

    Zhao, Mingxiao; Lau, Kim Kt; Zhou, Xian; Wu, Jianfang; Yang, Jun; Wang, Chang

    2017-03-28

    After a large-scale radiological accident, early-response biomarkers to assess radiation exposure over a broad dose range are not only the basis of rapid radiation triage, but are also the key to the rational use of limited medical resources and to the improvement of treatment efficiency. Because of its high throughput, rapid assays and minimally invasive sample collection, metabolomics has been applied to research into radiation exposure biomarkers in recent years. Due to the complexity of radiobiological effects, most of the potential biomarkers are both dose-dependent and time-dependent. In reality, it is very difficult to find a single biomarker that is both sensitive and specific in a given radiation exposure scenario. Therefore, a multi-parameters approach for radiation exposure assessment is more realistic in real nuclear accidents. In this study, untargeted metabolomic profiling based on gas chromatography-mass spectrometry (GC-MS) and targeted amino acid profiling based on LC-MS/MS were combined to investigate early urinary metabolite responses within 48 h post-exposure in a rat model. A few of the key early-response metabolites for radiation exposure were identified, which revealed the most relevant metabolic pathways. Furthermore, a panel of potential urinary biomarkers was selected through a multi-criteria approach and applied to early triage following irradiation. Our study suggests that it is feasible to use a multi-parameters approach to triage radiation damage, and the urinary excretion levels of the relevant metabolites provide insights into radiation damage and repair.

  10. Diversity in the early tertiary anthropoidean radiation in Africa.

    PubMed Central

    Simons, E L

    1992-01-01

    Between 1987 and 1991 recent field seasons in the Fayum Depression of Egypt have yielded five species and genera of primates that were earlier unknown. Three of these species and genera are described below. All these genera and species are known only from Fayum site L-41, which has been dated as of late Eocene age. In the Fayum, these 5 species from L-41 are added to 3 kinds of prosimians (1 species formally described) and 11 earlier named species of Anthropoidea. When certain undescribed species are added, the total of known Fayum primate species comes to 21, belonging to at least 10 genera, genera that, in turn, could belong to as many as seven families. This arguably represents more taxonomic diversity of primates, especially higher primates, than has been demonstrated before in one so spatially and temporally limited area. These facts argue that an important, perhaps primary, radiation of anthropoideans took place in the African Eocene. Images PMID:1438271

  11. 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.

  12. 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.

  13. Dependence of Early and Late Chromosomal Aberrations on Radiation Quality and Cell Types

    NASA Technical Reports Server (NTRS)

    Lu, Tao; Zhang, Ye; Krieger, Stephanie; Yeshitla, Samrawit; Goss, Rosalin; Bowler, Deborah; Kadhim, Munira; Wilson, Bobby; Rohde, Larry; Wu, Honglu

    2017-01-01

    Exposure to radiation induces different types of DNA damage, increases mutation and chromosome aberration rates, and increases cellular transformation in vitro and in vivo. The susceptibility of cells to radiation depends on genetic background and growth condition of cells, as well as types of radiation. Mammalian cells of different tissue types and with different genetic background are known to have different survival rate and different mutation rate after cytogenetic insults. Genomic instability, induced by various genetic, metabolic, and environmental factors including radiation, is the driving force of tumorigenesis. Accurate measurements of the relative biological effectiveness (RBE) is important for estimating radiation-related risks. To further understand genomic instability induced by charged particles and their RBE, we exposed human lymphocytes ex vivo, human fibroblast AG1522, human mammary epithelial cells (CH184B5F5/M10), and bone marrow cells isolated from CBA/CaH(CBA) and C57BL/6 (C57) mice to high energy protons and Fe ions. Normal human fibroblasts AG1522 have apparently normal DNA damage response and repair mechanisms, while mammary epithelial cells (M10) are deficient in the repair of DNA DSBs. Mouse strain CBA is radio-sensitive while C57 is radio-resistant. Metaphase chromosomes at different cell divisions after radiation exposure were collected and chromosome aberrations were analyzed as RBE for different cell lines exposed to different radiations at various time points up to one month post irradiation.

  14. On background radiation gradients--the use of airborne surveys when searching for orphan sources using mobile gamma-ray spectrometry.

    PubMed

    Kock, Peder; Rääf, Christopher; Samuelsson, Christer

    2014-02-01

    Systematic background radiation variations can lead to both false positives and failures to detect an orphan source when searching using car-borne mobile gamma-ray spectrometry. The stochastic variation at each point is well described by Poisson statistics, but when moving in a background radiation gradient the mean count rate will continually change, leading to inaccurate background estimations. Airborne gamma spectrometry (AGS) surveys conducted on the national level, usually in connection to mineral exploration, exist in many countries. These data hold information about the background radiation gradients which could be used at the ground level. This article describes a method that aims to incorporate the systematic as well as stochastic variations of the background radiation. We introduce a weighted moving average where the weights are calculated from existing AGS data, supplied by the Geological Survey of Sweden. To test the method we chose an area with strong background gradients, especially in the thorium component. Within the area we identified two roads which pass through the high-variability locations. The proposed method is compared with an unweighted moving average. The results show that the weighting reduces the excess false positives in the positive background gradients without introducing an excess of failures to detect a source during passage in negative gradients.

  15. 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.

  16. Molecular dating and biogeography of the early placental mammal radiation.

    PubMed

    Eizirik, E; Murphy, W J; O'Brien, S J

    2001-01-01

    The timing and phylogenetic hierarchy of early placental mammal divergences was determined based on combined DNA sequence analysis of 18 gene segments (9779 bp) from 64 species. Using rooted and unrooted phylogenies derived from distinct theoretical approaches, strong support for the divergence of four principal clades of eutherian mammals was achieved. Minimum divergence dates of the earliest nodes in the placental mammal phylogeny were estimated with a quartet-based maximum-likelihood method that accommodates rate variation among lineages using conservative fossil calibrations from nine different nodes in the eutherian tree. These minimum estimates resolve the earliest placental mammal divergence nodes at periods between 64 and 104 million years ago, in essentially every case predating the Cretaceous-Tertiary (K-T) boundary. The pattern and timing of these divergences allow a geographic interpretation of the primary branching events in eutherian history, likely originating in the southern supercontinent Gondwanaland coincident with its breakup into Africa and South America 95-105 million years ago. We propose an integrated genomic, paleontological, and biogeographic hypothesis to account for these earliest splits on the placental mammal family tree and address current discrepancies between fossil and molecular evidence.

  17. 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

  18. Radiation therapy of early carcinoma of the breast without mastectomy. [Linear acceleraor and iridium implants

    SciTech Connect

    Hellman, S.; Harris, J.R.; Levene, M.B.

    1980-08-15

    The results of the treatment of 176 patients with early breast cancer, using radiation therapy without mastectomy are reported. The likelihood of local recurrence was 5% for Stage I patients and 7% for Stage II patients. Local control was significantly greater in those patients receiving an iridium implant. The cumulative survival probability at five years is 96% for Stage I and 68% for Stage II. Gross tumor resection with careful reapproximation of the breast tissue and well-placed incisions facilitates the radiation therapy. Homogeneous external beam radiation to the breast and draining lymph nodes (4500 to 5000 rads) and supplemental local radiation to the sites of the primary lesion (in this series using interstitial implantation) are recommended. The frequency of normal tissue complications was low.

  19. 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

  20. 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

  1. 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.

  2. 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

  3. 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.

  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. 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.

  6. COLLAPSE OF MASSIVE MAGNETIZED DENSE CORES USING RADIATION MAGNETOHYDRODYNAMICS: EARLY FRAGMENTATION INHIBITION

    SciTech Connect

    Commercon, Benoit; Henning, Thomas; Hennebelle, Patrick

    2011-11-20

    We report the results of radiation-magnetohydrodynamics calculations in the context of high-mass star formation, using for the first time a self-consistent model for photon emission (i.e., via thermal emission and in radiative shocks) and with the high resolution necessary to properly resolve magnetic braking effects and radiative shocks on scales <100 AU. We investigate the combined effects of magnetic field, turbulence, and radiative transfer on the early phases of the collapse and the fragmentation of massive dense cores. We identify a new mechanism that inhibits initial fragmentation of massive dense cores where magnetic field and radiative transfer interplay. We show that this interplay becomes stronger as the magnetic field strength increases. Magnetic braking is transporting angular momentum outward and is lowering the rotational support and is thus increasing the infall velocity. This enhances the radiative feedback owing to the accretion shock on the first core. We speculate that highly magnetized massive dense cores are good candidates for isolated massive star formation while moderately magnetized massive dense cores are more appropriate forming OB associations or small star clusters.

  7. 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.

  8. [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.

  9. 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.

  10. 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.

  11. 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.

  12. Maps of Dust Infrared Emission for Use in Estimation of Reddening and Cosmic Microwave Background Radiation Foregrounds

    NASA Astrophysics Data System (ADS)

    Schlegel, David J.; Finkbeiner, Douglas P.; Davis, Marc

    1998-06-01

    standard reddening law and use the colors of elliptical galaxies to measure the reddening per unit flux density of 100 μm emission. We find consistent calibration using the B-R color distribution of a sample of the 106 brightest cluster ellipticals, as well as a sample of 384 ellipticals with B-V and Mg line strength measurements. For the latter sample, we use the correlation of intrinsic B-V versus Mg2 index to tighten the power of the test greatly. We demonstrate that the new maps are twice as accurate as the older Burstein-Heiles reddening estimates in regions of low and moderate reddening. The maps are expected to be significantly more accurate in regions of high reddening. These dust maps will also be useful for estimating millimeter emission that contaminates cosmic microwave background radiation experiments and for estimating soft X-ray absorption. We describe how to access our maps readily for general use.

  13. Gaugessence: a dark energy model with early time radiation-like equation of state

    NASA Astrophysics Data System (ADS)

    Mehrabi, Ahmad; Maleknejad, Azade; Kamali, Vahid

    2017-03-01

    In this work, we study a new quintessence model associated with non-Abelian gauge fields, minimally coupled to Einstein gravity. This gauge theory has been recently introduced and studied as an inflationary model, called gauge-flation. Here, however, we are interested in the late time cosmology of the model in the presence of matter and radiation to explain the present time accelerating Universe. During the radiation and matter eras, the gauge field tracks radiation and basically acts like a dark radiation sector. As we approach lower redshifts, the dark component takes the form of a dark energy source which eventually becomes the dominate part of the energy budget of the Universe. Due to the tracking feature of our model, solutions with different initial values are attracted to a common trajectory. The existence of early dark radiation is a robust prediction of our model which contributes to the effective number of relativistic species, N_{eff} and has its own interesting observational features.

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. Predicting the macroseismic intensity from early radiated P wave energy for on-site earthquake early warning in Italy

    NASA Astrophysics Data System (ADS)

    Brondi, P.; Picozzi, M.; Emolo, A.; Zollo, A.; Mucciarelli, M.

    2015-10-01

    Earthquake Early Warning Systems (EEWS) are potentially effective tools for risk mitigation in active seismic regions. The present study explores the possibility of predicting the macroseismic intensity within EEW timeframes using the squared velocity integral (IV2) measured on the early P wave signals, a proxy for the P wave radiated energy of earthquakes. This study shows that IV2 correlates better than the peak displacement measured on P waves with both the peak ground velocity and the Housner Intensity, with the latter being recognized by engineers as a reliable proxy for damage assessment. Therefore, using the strong motion recordings of the Italian Accelerometric Archive, a novel relationship between the parameter IV2 and the macroseismic intensity (IM) has been derived. The validity of this relationship has been assessed using the strong motion recordings of the Istituto Nazionale di Geofisica e Vulcanologia Strong Motion Data and Osservatorio Sismico delle Strutture databases, as well as, in the case of the MW 6, 29 May 2012 Emilia earthquake (Italy), comparing the predicted intensities with the ones observed after a macroseismic survey. Our results indicate that P wave IV2 can become a key parameter for the design of on-site EEWS, capable of proving real-time predictions of the IM at target sites.

  19. 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

  20. 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.

  1. Exposure to indoor background radiation and urinary concentrations of 8-hydroxydeoxyguanosine, a marker of oxidative DNA damage.

    PubMed Central

    Sperati, A; Abeni, D D; Tagesson, C; Forastiere, F; Miceli, M; Axelson, O

    1999-01-01

    We investigated whether exposure to indoor [gamma]-radiation and radon might be associated with enough free radical formation to increase urinary concentrations of 8-hydroxydeoxyguanosine (8-OHdG), a sensitive marker of DNA damage, due to a hydroxyl radical attack at the C8 of guanine. Indoor radon and [gamma]-radiation levels were measured in 32 dwellings for 6 months by solid-state nuclear track detectors and thermoluminescent dosimeters, respectively. Urine samples for 8-OHdG determinations were obtained from 63 healthy adult subjects living in the measured dwellings. An overall tendency toward increasing levels of 8-OHdG with increasing levels of radon and [gamma]-radiation was seen in the females, presumably due to their estimated longer occupancy in the dwellings measured. Different models were considered for females, with the steepest slopes obtained for [gamma]-radiation with a coefficient of 0.500 (log nmol/l of 8-OHdG for each unit increase of [gamma]-radiation on a log scale) (p<0.01), and increasing to 0.632 (p = 0.035), but with larger variance, when radon was included in the model. In conclusion, there seems to be an effect of indoor radioactivity on the urinary excretion of 8-OHdG for females, who are estimated to have a higher occupancy in the dwellings measured than for males, for whom occupational and other agents may also influence 8-OHdG excretion. ree radicals; [gamma]-radiation; radon. PMID:10064551

  2. 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.

  3. 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.

  4. 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

  5. Fluorescence background subtraction technique for hybrid fluorescence molecular tomography/x-ray computed tomography imaging of a mouse model of early stage lung cancer

    NASA Astrophysics Data System (ADS)

    Ale, Angelique; Ermolayev, Vladimir; Deliolanis, Nikolaos C.; Ntziachristos, Vasilis

    2013-05-01

    The ability to visualize early stage lung cancer is important in the study of biomarkers and targeting agents that could lead to earlier diagnosis. The recent development of hybrid free-space 360-deg fluorescence molecular tomography (FMT) and x-ray computed tomography (XCT) imaging yields a superior optical imaging modality for three-dimensional small animal fluorescence imaging over stand-alone optical systems. Imaging accuracy was improved by using XCT information in the fluorescence reconstruction method. Despite this progress, the detection sensitivity of targeted fluorescence agents remains limited by nonspecific background accumulation of the fluorochrome employed, which complicates early detection of murine cancers. Therefore we examine whether x-ray CT information and bulk fluorescence detection can be combined to increase detection sensitivity. Correspondingly, we research the performance of a data-driven fluorescence background estimator employed for subtraction of background fluorescence from acquisition data. Using mice containing known fluorochromes ex vivo, we demonstrate the reduction of background signals from reconstructed images and sensitivity improvements. Finally, by applying the method to in vivo data from K-ras transgenic mice developing lung cancer, we find small tumors at an early stage compared with reconstructions performed using raw data. We conclude with the benefits of employing fluorescence subtraction in hybrid FMT-XCT for early detection studies.

  6. 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.

  7. 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.

  8. The biliprotein C-phycocyanin modulates the early radiation response: a pilot study.

    PubMed

    Ivanova, Katia G; Stankova, Katia G; Nikolov, Vladimir N; Georgieva, Radostina T; Minkova, Kaledona M; Gigova, Lili G; Rupova, Ivanka T; Boteva, Rayna N

    2010-01-01

    This study analyzed the effects of biliprotein C-phycocyanin (C-PC) on the enzymatic antioxidant defence system in lymphocytes of nuclear power-plant workers and non-exposed controls. Changes in the protein levels of manganese super oxide dismutase (MnSOD), catalase and glutathione-S-transferase (GST) were used as markers for early biological effects of a single in vitro exposure of cells to: (i) 2Gy gamma rays; (ii) 5muM C-PC; and (iii) a combination of C-PC plus irradiation with 2Gy. The results showed that C-PC selectively stimulated the lymphocyte antioxidant defence system of occupationally exposed subjects. The activation of the antioxidant protective mechanisms as part of the early radiation response was probably related to the chronic low-dose occupational exposure. The modulating capacity of C-PC at the molecular level may be of interest for the protection of occupationally exposed persons.

  9. 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)

  10. 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

  11. Discovery of an ornithurine bird and its implication for Early Cretaceous avian radiation.

    PubMed

    Zhou, Zhonghe; Zhang, Fucheng

    2005-12-27

    An ornithurine bird, Hongshanornis longicresta gen. et sp. nov., represented by a nearly complete and articulated skeleton in full plumage, has been recovered from the lacustrine deposits of the Lower Cretaceous Jehol Group in Inner Mongolia, northeast China. The bird had completely reduced teeth and possessed a beak in both the upper and lower jaws, representing the earliest known beaked ornithurine. The preservation of a predentary bone confirms that this structure is not unique to ornithischian dinosaurs but was common in early ornithurine birds. This small bird had a strong flying capability with a low aspect ratio wing. It was probably a wader, feeding in shallow water or marshes. This find confirms that the aquatic environment had played a key role in the origin and early radiation of ornithurines, one branch of which eventually gave rise to extant birds near the Cretaceous/Tertiary boundary. This discovery provides important information not only for studying the origin and early evolution of ornithurines but also for understanding the differentiation in morphology, body size, and diet of the Early Cretaceous birds.

  12. 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.

  13. Measurements of background radiation levels around Indian station Bharati, during 33rd Indian Scientific Expedition to Antarctica.

    PubMed

    Bakshi, A K; Prajith, Rama; Chinnaesakki, S; Pal, Rupali; Sathian, Deepa; Dhar, Ajay; Selvam, T Palani; Sapra, B K; Datta, D

    2017-02-01

    A comprehensive measurement of radioactivity concentrations of the primordial radionuclides (238)U, (232)Th and (40)K and their decay products in the soil samples collected from the sites of Indian research stations, Bharati and Maitri, at Antarctica was carried out using gamma spectrometric method. The activity concentrations in the soil samples of Bharati site were observed to be few times higher than of Maitri site. The major contributor to radioactivity content in the soil at Bharati site is (232)Th radionuclide in higher concentration. The gamma radiation levels based on the measured radioactivity of soil samples were calculated using the equation given in UNSCEAR 2000. The calculated radiation levels were compared with the measured values and found to correlate reasonably well. The study could be useful for the scientists working at Antarctica especially those at Indian station to take decision to avoid areas with higher radioactivity before erecting any facility for long term experiment or use.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. The sensitivity of Arctic Sea ice to cloud radiative conditions in spring and early summer

    NASA Astrophysics Data System (ADS)

    King, Michalea D.

    The rapid decline in Arctic sea ice is a key driver of the amplified warming signal observed in the Arctic region, making this a critical phenomenon in climate science. Accurate seasonal sea ice projections, however, remain challenging due to a large degree of interannual variability in sea ice extent. This study analyzed the role of clouds in the early melt season, and their associated surface radiative effects, in modulating the magnitude of sea ice loss. A combination of observed and modeled sea ice thickness data was used to track temporal and spatial patterns of sea ice volume loss. A stepwise multiple linear regression analysis revealed that variants of Arctic cloud radiative fluxes in March and June were valuable in predicting the total volume of sea ice loss during the melt season. This study then explored the causalities behind the particular variable selection by the regression model, which yielded an adjusted R2 value of 0.88. Downwelling longwave cloud radiative fluxes in March were found to be negatively correlated with melt onset, with enhanced downward fluxes initiating earlier melt. Downwelling longwave fluxes in June were interpreted to be significant due to the large volume of ice volume lost in June, as well as the heightened effect of clouds on the surface radiative budget during periods of maximum insolation. Sea ice loss can also be influenced by the spatial patterns and magnitude of sea ice advection. Anomalous surface wind conditions and resulting anomalies in sea ice advection, were found to be critical in 2013, a year that fell outside the confidence interval of the regression model.

  19. [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.

  20. 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…

  1. 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

  2. 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.

  3. 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.

  4. Distinct abnormalities of the primate prefrontal cortex caused by ionizing radiation in early or midgestation

    PubMed Central

    Selemon, Lynn D.; Ceritoglu, Can; Ratnanather, J.Tilak; Wang, Lei; Harms, Michael P.; Aldridge, Kristina; Begovic', Anita; Csernansky, John G.; Miller, Michael I.; Rakic, Pasko

    2012-01-01

    Prenatal exposure of the brain to environmental insult causes different neurological symptoms and behavioral outcomes depending on the time of exposure. To examine the cellular bases for these differences, we exposed Rhesus macaque fetuses to x-rays during early gestation (E30–E42), i.e., before the onset of corticogenesis, or in midgestation (E70–E81) when superficial cortical layers are generated. Animals were delivered at term (~E165), and the size and cellular composition of prefrontal association cortex (area 46) examined in adults, using magnetic resonance imaging (MRI) and stereologic analysis. Both early and midgestational radiation exposure diminished the surface area and volume of area 46. However, early exposure spared cortical thickness and did not alter laminar composition, and due to higher cell density, neuron number was within the normal range. In contrast, exposure to x-rays at midgestation reduced cortical thickness, mainly due to elimination of neurons destined for the superficial layers. A cell-sparse gap, observed within layer III, was not filled by the later generated neurons destined for layer II, indicating that there is no subsequent replacement of the lost neurons. The distinct areal and laminar pathology consequent to temporally segregated irradiation is consistent with basic postulates of the radial unit hypothesis of cortical development. In addition, we show that an environmental disturbance inflicted in early gestation can induce subtle cytoarchitectonic alterations without loss of neurons, such as those observed in schizophrenia, whereas midgestational exposure causes selective elimination of neurons and cortical thinning as observed in some forms of mental retardation and fetal alcohol syndrome. PMID:22911497

  5. 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.

  6. 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.

  7. 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…

  8. 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.

  9. The Cosmic Microwave Background and its Polarization

    NASA Astrophysics Data System (ADS)

    Wollack, Edward

    2017-01-01

    The subtle spatial variations in the cosmic microwave background (CMB) radiation provide a unique astrophysical probe of the early Universe. Characterization of this relic radiation and its polarization have the power to reveal and constrain the properties of light astroparticle species, long wave gravitational radiation, and intervening mass concentrations. Recent advances in theory, observation, and instrumentation have set the stage to experimentally confront the inflationary paradigm via precision polarimetric surveys of the CMB. Current and proposed future observational efforts from the ground, balloon, and spaceborne platforms will be briefly surveyed in this presentation. Recent community activities by the Inflation Probe Science Interest Group (IPSIG) will also be presented.

  10. 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.

  11. 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.

  12. 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.

  13. Early changes in the ultrastructure of the pars intermedia of the pituitary of Xenopus laevis after change of background color.

    PubMed

    Volcanes, B D; Weatherhead, B

    1976-01-01

    Stereological analysis of the secretory cells of the pars intermedia of Xenopus laevis over a period of 3 days following the transfer of animals from a white to a black background has revealed that significant alterations in the ultrastructural appearance of these cells can be detected 8 h after the transfer. In particular, changes in the secretory granules and the rough endoplasmic reticulum were found to correlate well with previous reports concerning the melanocyte-stimulating hormone (MSH) content and the capacity for protein synthesis of the pars intermedia.

  14. 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.

  15. 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

  16. 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.

  17. Magnetic resonance spectroscopic imaging of brain injury after nasopharyngeal cancer radiation in early delayed reaction.

    PubMed

    Chen, W-S; Li, J-J; Zhang, J-H; Hong, L; Xing, Z-B; Wang, F; Li, C-Q

    2014-08-29

    This study aimed to investigate the value of magnetic resonance spectroscopy (MRS) imaging in assessing nasopharyngeal carcinoma radiotherapy during the early delayed reaction period. Eighty cases of nasopharyngeal cancer treated with radiotherapy within the same period underwent MRS imaging before or after radiotherapy. Of the 80 cases, 47 underwent MRS imaging on the 3rd, 4th, 6th, and 12th months after radiotherapy. The trends of the primary metabolite concentration at different time points were monitored and compared with the corresponding data after radiotherapy. Repeated measures analysis of variance was performed. At the end of radiotherapy, the N-acetyl aspartate (NAA)/creatine (Cr), choline (Cho)/Cr, and NAA/Cho ratios were reduced to the lowest levels after 3 months. However, increasing trends were observed from the 4th to the 12th month. On the 12th month, stable levels were reached with statistically significant differences (F = 316.02, 53.84, 286.68; P < 0.01). MRS reflected the radiation injury-repair process in the brain of a nasopharyngeal cancer patient during early delayed reaction. This non-invasive monitoring of changes in brain tissue metabolite concentrations provides valuable information for prognosis.

  18. 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.

  19. Theoretical analysis of the background intensity distribution in X-ray Birefringence Imaging using synchrotron bending-magnet radiation

    NASA Astrophysics Data System (ADS)

    Sutter, John P.; Dolbnya, Igor P.; Collins, Stephen P.; Harris, Kenneth D. M.; Edwards-Gau, Gregory R.; Palmer, Benjamin A.

    2015-04-01

    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.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Detection and early phase assessment of radiation-induced lung injury in mice using micro-CT.

    PubMed

    Saito, Shigeyoshi; Murase, Kenya

    2012-01-01

    Radiation therapy is an important therapeutic modality for thoracic malignancies. However, radiation-induced pulmonary injuries such as radiation pneumonitis and fibrosis are major dose-limiting factors. Previous research shows that micro-computed tomography (micro-CT) can detect radiation-induced lung injuries a few months following irradiation, but studies to assess the early response of lung tissue are lacking. The aim of this study was to determine if micro-CT could be used to detect and assess early-phase radiation-induced lung injury in mice. Twenty-one animals were divided into three groups: normal (n = 7), one day after x-ray exposure (n = 7), and at four days after x-ray exposure (n = 7). The x-ray-exposed groups received a single dose of 20 Gy, to the whole lung. Histology showed enlargements of the air space (Lm: mean chord length) following irradiation. 40.5 ± 3.8 µm and 60.0 ± 6.9 µm were observed after one and four days, respectively, compared to 26.5 ± 3.1 µm in normal mice. Three-dimensional micro-CT images were constructed and histograms of radiodensity - Hounsfield Units (HU) - were used to assess changes in mouse lungs. Radiation-induced lung injury was observed in irradiated mice, by the use of two parameters which were defined as shifts in peak HU between -200 to -800 HU (Peak(HU)) and increase in the number of pixels at -1000 HU (Number(-1000)). These parameters were correlated with histological changes. The results demonstrate that micro-CT can be used for the early detection and assessment of structural and histopathological changes resulting from radiation-induced lung injury in mice. Micro-CT has the advantage, over traditional histological techniques, of allowing longitudinal studies of lung disease progression and assessment of the entire lung, while reducing the number of animals required for such studies.

  11. The VicGeneration study - a birth cohort to examine the environmental, behavioural and biological predictors of early childhood caries: background, aims and methods

    PubMed Central

    2010-01-01

    Background Dental caries (decay) during childhood is largely preventable however it remains a significant and costly public health concern, identified as the most prevalent chronic disease of childhood. Caries in children aged less than five years (early childhood caries) is a rapid and progressive disease that can be painful and debilitating, and significantly increases the likelihood of poor child growth, development and social outcomes. Early childhood caries may also result in a substantial social burden on families and significant costs to the public health system. A disproportionate burden of disease is also experienced by disadvantaged populations. Methods/Design This study involves the establishment of a birth cohort in disadvantaged communities in Victoria, Australia. Children will be followed for at least 18 months and the data gathered will explore longitudinal relationships and generate new evidence on the natural history of early childhood caries, the prevalence of the disease and relative contributions of risk and protective biological, environmental and behavioural factors. Specifically, the study aims to: 1. Describe the natural history of early childhood caries (at ages 1, 6, 12 and 18 months), tracking pathways from early bacterial colonisation, through non-cavitated enamel white spot lesions to cavitated lesions extending into dentine. 2. Enumerate oral bacterial species in the saliva of infants and their primary care giver. 3. Identify the strength of concurrent associations between early childhood caries and putative risk and protective factors, including biological (eg microbiota, saliva), environmental (fluoride exposure) and socio-behavioural factors (proximal factors such as: feeding practices and oral hygiene; and distal factors such as parental health behaviours, physical health, coping and broader socio-economic conditions). 4. Quantify the longitudinal relationships between these factors and the development and progression of early

  12. Environmental exposure to low-doses of ionizing radiation. Effects on early nephrotoxicity in mice.

    PubMed

    Bellés, Montserrat; Gonzalo, Sergio; Serra, Noemí; Esplugas, Roser; Arenas, Meritxell; Domingo, José Luis; Linares, Victoria

    2017-03-31

    Nuclear accidents of tremendous magnitude, such as those of Chernobyl (1986) and Fukushima (2011), mean that individuals living in the contaminated areas are potentially exposed to ionizing radiation (IR). However, the dose-response relationship for effects of low doses of radiation is not still established. The present study was aimed at investigating in mice the early effects of low-dose internal radiation exposure on the kidney. Adult male (C57BL/6J) mice were divided into three groups. Two groups received a single subcutaneous (s.c.) doses of cesium ((137)Cs) with activities of 4000 and 8000Bq/kg bw. A third group (control group) received a single s.c. injection of 0.9% saline. To evaluate acute and subacute effects, mice (one-half of each group) were euthanized at 72h and 10 days post-exposure to (137)Cs, respectively. Urine samples were collected for biochemical analysis, including the measurement of F2-isoprostane (F2-IsoP) and kidney injury molecule-1 (KIM-1) levels. Moreover, the concentrations of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a sensitive marker of oxidative DNA damage, were measured in renal tissue. Urinary excretion of total protein significantly increased at 72h in mice exposed to Cs4000. Uric acid and lactate dehydrogenase (LDH) decreased significantly at both times post-exposure in animals exposed to Cs8000. After 72h and 10d of exposure to Cs4000, a significant increase in the γ-glutamil transferase (GGT) and N-acetyl-β-D-glucosaminidase (NAG) activities was observed. In turn, F2-IsoP levels increased -mainly in the Cs4000 group- at 72h post-exposure. Following irradiation ((137)Cs), the highest level of KIM-1 was corresponded to the Cs4000 group at 72h. Likewise, the main DNA damage was detected in mice exposed to Cs4000, mainly at 10d after irradiation. The alterations observed in several biomarkers suggest an immediate renal damage following exposure to low doses of IR (given as (137)Cs). Further investigations are required to clarify

  13. 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.

  14. NATURAL RADIOACTIVITY LEVEL AND ELEMENTAL COMPOSITION OF SOIL SAMPLES FROM A HIGH BACKGROUND RADIATION AREA ON EASTERN COAST OF INDIA (ODISHA).

    PubMed

    Sahoo, S K; Kierepko, R; Sorimachi, A; Omori, Y; Ishikawa, T; Tokonami, S; Prasad, G; Gusain, G S; Ramola, R C

    2016-10-01

    A comprehensive study was carried out to determine the radioactivity concentration of soil samples from different sites of a high background radiation area in the eastern coast of India, Odisha state. The dose rate measured in situ varied from 0.25 to 1.2 µSv h(-1) The gamma spectrometry measurements indicated Th series elements as the main contributors to the enhanced level of radiation and allowed the authors to find the mean level of the activity concentration (±SD) for (226)Ra, (228)Th and (40)K as 130±97, 1110±890 and 360±140 Bq kg(-1), respectively. Human exposure from radionuclides occurring outdoor was estimated based on the effective dose rate, which ranged from 0.14±0.02 to 2.15±0.26 mSv and was higher than the UNSCEAR annual worldwide average value 0.07 mSv. Additionally, X-ray fluorescence analysis provided information about the content of major elements in samples and indicated the significant amount of Ti (7.4±4.9 %) in soils.

  15. Assessment of environmental (226)Ra, (232)Th and (40)K concentrations in the region of elevated radiation background in Segamat District, Johor, Malaysia.

    PubMed

    Saleh, Muneer Aziz; Ramli, Ahmad Termizi; Alajerami, Yasser; Aliyu, Abubakar Sadiq

    2013-10-01

    Extensive environmental survey and measurements of gamma radioactivity in the soil samples collected from Segamat District were conducted. Two gamma detectors were used for the measurements of background radiation in the area and the results were used in the computation of the mean external radiation dose rate and mean weighted dose rate, which are 276 nGy h(-1) and 1.169 mSv y(-1), respectively. A high purity germanium (HPGe) detector was used in the assessment of activity concentrations of (232)Th, (226)Ra and (40)K. The results of the gamma spectrometry range from 11 ± 1 to 1210 ± 41 Bq kg(-1) for (232)Th, 12 ± 1 to 968 ± 27 Bq kg(-1) for (226)Ra, and 12 ± 2 to 2450 ± 86 Bq kg(-1) for (40)K. Gross alpha and gross beta activity concentrations range from 170 ± 50 to 4360 ± 170 Bq kg(-1) and 70 ± 20 to 4690 ± 90 Bq kg(-1), respectively. These results were used in the plotting of digital maps (using ARCGIS 9.3) for isodose. The results are compared with values giving in UNSCEAR 2000.

  16. Background sources at PEP

    SciTech Connect

    Lynch, H.; Schwitters, R.F.; Toner, W.T.

    1988-01-01

    Important sources of background for PEP experiments are studied. Background particles originate from high-energy electrons and positrons which have been lost from stable orbits, ..gamma..-rays emitted by the primary beams through bremsstrahlung in the residual gas, and synchrotron radiation x-rays. The effect of these processes on the beam lifetime are calculated and estimates of background rates at the interaction region are given. Recommendations for the PEP design, aimed at minimizing background are presented. 7 figs., 4 tabs.

  17. Cytokines, fatigue, and cutaneous erythema in early stage breast cancer patients receiving adjuvant radiation therapy.

    PubMed

    De Sanctis, Vitaliana; Agolli, Linda; Visco, Vincenzo; Monaco, Flavia; Muni, Roberta; Spagnoli, Alessandra; Campanella, Barbara; Valeriani, Maurizio; Minniti, Giuseppe; Osti, Mattia F; Amanti, Claudio; Pellegrini, Patrizia; Brunetti, Serena; Costantini, Anna; Alfò, Marco; Torrisi, Maria Rosaria; Marchetti, Paolo; Enrici, Riccardo Maurizi

    2014-01-01

    We investigated the hypothesis that patients developing high-grade erythema of the breast skin during radiation treatment could be more likely to present increased levels of proinflammatory cytokines which may lead, in turn, to associated fatigue. Forty women with early stage breast cancer who received adjuvant radiotherapy were enrolled from 2007 to 2010. Fatigue symptoms, erythema, and cytokine levels (IL-1β, IL-2, IL6, IL-8, TNF-α, and MCP-1) were registered at baseline, during treatment, and after radiotherapy completion. Seven (17.5%) patients presented fatigue without associated depression/anxiety. Grade ≥2 erythema was observed in 5 of these 7 patients. IL-1β, IL-2, IL-6, and TNF-α were statistically increased 4 weeks after radiotherapy (P < 0.05). After the Heckman two-step analysis, a statistically significant influence of skin erythema on proinflammatory markers increase (P = 0.00001) was recorded; in the second step, these blood markers showed a significant impact on fatigue (P = 0.026). A seeming increase of fatigue, erythema, and proinflammatory markers was observed between the fourth and the fifth week of treatment followed by a decrease after RT. There were no significant effects of hormone therapy, breast volume, and anemia on fatigue. Our study seems to suggest that fatigue is related to high-grade breast skin erythema during radiotherapy through the increase of cytokines levels.

  18. Radiation therapy for early stage unfavorable Hodgkin lymphoma: is dose reduction feasible?

    PubMed

    Laskar, Siddhartha; Kumar, Deepak P; Khanna, Nehal; Menon, Hari; Sengar, Manju; Arora, Brijesh; Gujral, Sumeet; Shet, Tanuja; Sridhar, Epari; Rangarajan, Venkatesh; Muckaden, Mary Ann; Nair, Reena; Banavali, Shripad

    2014-10-01

    One hundred and fifty-one patients aged between 3 and 70 years with early stage unfavorable Hodgkin lymphoma were included. Patients received 4-6 cycles of ABVD (doxorubicin, bleomycin, vinblastine and dacarbazine) chemotherapy and involved field radiation therapy (IFRT). The most common histology was mixed cellularity (43%). The majority had stage IIAX disease. IFRT doses were 25.2 Gy/14 fractions and 34.2 Gy/19 fractions for adults with a complete response (CR) and partial response (PR), respectively, while the doses were 19.8 Gy/11 fractions and 30.6 Gy/17 fractions, respectively, for children. After 60 months (median), the 10-year progression-free survival (PFS) and overall survival (OS) were 88.4% and 93.2%, respectively. On univariate analysis, prognostic factors with significant impact on PFS were age ≥ 18 years, nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) histology, extranodal disease and response to treatment. Extranodal disease had a significant impact on OS. On multivariate analysis, NLPHL histology (p = 0.001) and response at 3 months (p = 0.000) had a significant impact on PFS. There were no in-field relapses in patients with bulky disease receiving RT doses > 25.2 Gy. Chemotherapy related acute pulmonary toxicity was documented in 21.4% and 4.8% of patients after six and four cycles of ABVD chemotherapy (p = 0.041). Four cycles of ABVD and reduced dose IFRT resulted in optimal outcomes.

  19. 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.

  20. 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.

  1. 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…

  2. 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

  3. MicroRNA Expression for Early Prediction of Late Occurring Hematologic Acute Radiation Syndrome in Baboons

    PubMed Central

    Port, Matthias; Herodin, Francis; Valente, Marco; Drouet, Michel; Ullmann, Reinhard; Doucha-Senf, Sven; Lamkowski, Andreas; Majewski, Matthäus; Abend, Michael

    2016-01-01

    For effective medical management of radiation-exposed persons after a radiological/nuclear event, blood-based screening measures in the first few days that could predict hematologic acute radiation syndrome (HARS) are needed. For HARS severity prediction, we used microRNA (miRNA) expression changes measured on days one and two after irradiation in a baboon model. Eighteen baboons underwent different patterns of partial or total body irradiation, corresponding to an equivalent dose of 2.5 or 5 Gy. According to changes in blood cell counts (BCC) the surviving baboons (n = 17) exhibited mild (H1-2, n = 4) or more severe (H2-3, n = 13) HARS. In a two Stage study design we screened 667 miRNAs using a quantitative real-time polymerase chain reaction (qRT-PCR) platform. In Stage II we validated candidates where miRNAs had to show a similar regulation (up- or down-regulated) and a significant 2-fold miRNA expression difference over H0. Seventy-two candidate miRNAs (42 for H1-2 and 30 for H2-3) were forwarded for validation. Forty-two of the H1-2 miRNA candidates from the screening phase entered the validation step and 20 of them showed a statistically significant 2–4 fold up-regulation relative to the unexposed reference (H0). Fifteen of the 30 H2-3 miRNAs were validated in Stage II. All miRNAs appeared 2–3 fold down-regulated over H0 and allowed an almost complete separation of HARS categories; the strongest candidate, miR-342-3p, showed a sustained and 10-fold down-regulation on both days 1 and 2. In summary, our data support the medical decision making of the HARS even within the first two days after exposure where diagnostic tools for early medical decision are required but so far missing. The miRNA species identified and in particular miR-342-3p add to the previously identified mRNAs and complete the portfolio of identified mRNA and miRNA transcripts for HARS prediction and medical management. PMID:27846229

  4. MicroRNA Expression for Early Prediction of Late Occurring Hematologic Acute Radiation Syndrome in Baboons.

    PubMed

    Port, Matthias; Herodin, Francis; Valente, Marco; Drouet, Michel; Ullmann, Reinhard; Doucha-Senf, Sven; Lamkowski, Andreas; Majewski, Matthäus; Abend, Michael

    2016-01-01

    For effective medical management of radiation-exposed persons after a radiological/nuclear event, blood-based screening measures in the first few days that could predict hematologic acute radiation syndrome (HARS) are needed. For HARS severity prediction, we used microRNA (miRNA) expression changes measured on days one and two after irradiation in a baboon model. Eighteen baboons underwent different patterns of partial or total body irradiation, corresponding to an equivalent dose of 2.5 or 5 Gy. According to changes in blood cell counts (BCC) the surviving baboons (n = 17) exhibited mild (H1-2, n = 4) or more severe (H2-3, n = 13) HARS. In a two Stage study design we screened 667 miRNAs using a quantitative real-time polymerase chain reaction (qRT-PCR) platform. In Stage II we validated candidates where miRNAs had to show a similar regulation (up- or down-regulated) and a significant 2-fold miRNA expression difference over H0. Seventy-two candidate miRNAs (42 for H1-2 and 30 for H2-3) were forwarded for validation. Forty-two of the H1-2 miRNA candidates from the screening phase entered the validation step and 20 of them showed a statistically significant 2-4 fold up-regulation relative to the unexposed reference (H0). Fifteen of the 30 H2-3 miRNAs were validated in Stage II. All miRNAs appeared 2-3 fold down-regulated over H0 and allowed an almost complete separation of HARS categories; the strongest candidate, miR-342-3p, showed a sustained and 10-fold down-regulation on both days 1 and 2. In summary, our data support the medical decision making of the HARS even within the first two days after exposure where diagnostic tools for early medical decision are required but so far missing. The miRNA species identified and in particular miR-342-3p add to the previously identified mRNAs and complete the portfolio of identified mRNA and miRNA transcripts for HARS prediction and medical management.

  5. 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

  6. Terrestrial gamma dose rate, radioactivity and radiological hazards in the rocks of an elevated radiation background in Juban District, Ad Dali' Governorate, Yemen.

    PubMed

    Abdurabu, Wedad Ali; Ramli, Ahmad Termizi; Saleh, Muneer Aziz; Heryansyah, Arien; Alnhary, Anees; Fadhl, Shadi

    2016-03-01

    This study aims to evaluate natural radiation and radioactivity in the rock and to assess the corresponding health risk in a region of elevated background radiation in Juban District, Ad Dali' Governorate, Yemen. The mean external gamma dose rate was 374 nGy h(-1) which is approximately six times the world average. The measured results were used to compute annual effective dose equivalent, collective effective dose and excess lifetime cancer risk, which are 2.298 mSv, 61.95 man Sv y(-1) and 8.043  ×  10(-3), respectively. Rocks samples from different geological formations were analyzed for quantitative determination of (226)Ra, (232)Th and (40)K. The specific activity of the rocks samples ranges from 7  ±  1 Bq Kg(-1) to 12 513  ±  329 Bq Kg(-1) for (232)Th, from 6  ±  1 Bq kg(-1) to 3089  ±  74 Bq kg(-1) for (226)Ra and 702  ±  69 Bq kg(-1) to 2954  ±  285 Bq kg(-1) for (40)K. (232)Th is the main contributor to gamma dose rate from the rock samples. Indicators of radiological health impact, radium equivalent activity and external hazard index are 3738 Bq kg(-1) and 10.10, respectively. The mean external hazard index was ten times unity in the studied locations in Juban District, which is higher than the recommended value.

  7. 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.

  8. 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).

  9. 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...

  10. Intensity-modulated radiation therapy for early-stage breast cancer: is it ready for prime time?

    PubMed Central

    Chan, Tabitha Y; Tan, Poh Wee; Tang, Johann I

    2017-01-01

    Whole breast external beam radiotherapy (WBEBRT) is commonly used as an essential arm in the treatment management of women with early-stage breast cancer. Dosimetry planning for conventional WBEBRT typically involves a pair of tangential fields. Advancement in radiation technology and techniques has the potential to improve treatment outcomes with clinically meaningful long-term benefits. However, this advancement must be balanced with safety and improved efficacy. Intensity-modulated radiation therapy (IMRT) is an advanced technique that shows promise in improving the planning process and radiation delivery. Early data on utilizing IMRT for WBEBRT demonstrate more homogenous dose distribution with reduction in organs at risk doses. This translates to toxicities reduction. The two common descriptors for IMRT are forward-planning “fields in field” and inverse planning. Unlike IMRT for other organs, the aim of IMRT for breast planning is to achieve dose homogeneity and not organ conformality. The aim of this paper was to evaluate whether IMRT is ready for prime time based on these three points: 1) workload impact, 2) the clinical impact on the patient’s quality of life, and 3) the appropriateness and applicability to clinical practice. PMID:28360536

  11. TP53inp1 Gene Is Implicated in Early Radiation Response in Human Fibroblast Cells.

    PubMed

    Sándor, Nikolett; Schilling-Tóth, Boglárka; Kis, Enikő; Fodor, Lili; Mucsányi, Fruzsina; Sáfrány, Géza; Hegyesi, Hargita

    2015-10-23

    Tumor protein 53-induced nuclear protein-1 (TP53inp1) is expressed by activation via p53 and p73. The purpose of our study was to investigate the role of TP53inp1 in response of fibroblasts to ionizing radiation. γ-Ray radiation dose-dependently induces the expression of TP53inp1 in human immortalized fibroblast (F11hT) cells. Stable silencing of TP53inp1 was done via lentiviral transfection of shRNA in F11hT cells. After irradiation the clonogenic survival of TP53inp1 knockdown (F11hT-shTP) cells was compared to cells transfected with non-targeting (NT) shRNA. Radiation-induced senescence was measured by SA-β-Gal staining and autophagy was detected by Acridine Orange dye and microtubule-associated protein-1 light chain 3 (LC3B) immunostaining. The expression of TP53inp1, GDF-15, and CDKN1A and alterations in radiation induced mitochondrial DNA deletions were evaluated by qPCR. TP53inp1 was required for radiation (IR) induced maximal elevation of CDKN1A and GDF-15 expressions. Mitochondrial DNA deletions were increased and autophagy was deregulated following irradiation in the absence of TP53inp1. Finally, we showed that silencing of TP53inp1 enhances the radiation sensitivity of fibroblast cells. These data suggest functional roles for TP53inp1 in radiation-induced autophagy and survival. Taken together, we suppose that silencing of TP53inp1 leads radiation induced autophagy impairment and induces accumulation of damaged mitochondria in primary human fibroblasts.

  12. 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

  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. Long-term follow-up of testicular function following radiation therapy for early-stage Hodgkin's disease

    SciTech Connect

    Kinsella, T.J.; Trivette, G.; Rowland, J.; Sorace, R.; Miller, R.; Fraass, B.; Steinberg, S.M.; Glatstein, E.; Sherins, R.J.

    1989-06-01

    Seventeen male patients with pathological staged I-IIIA1 Hodgkin's disease were followed prospectively for radiation damage to the testes from low-dose scattered irradiation. During conventionally fractionated radiation therapy, the testicular dose ranged from 6 to 70 cGy. Testicular function was measured in a prospective fashion by repeated analyses (every 6 to 12 months) of serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone. Patients were also followed by serial semen analyses and by a questionnaire on fertility. The follow-up period ranged from 3 to 7 years after completion of radiation therapy. In patients receiving greater than or equal to 20 cGy, there was a dose-dependent increase in serum FSH values following irradiation, with the maximum difference at 6 months compared with pretreatment levels. All patients showed a return to normal FSH values within 12 to 24 months following irradiation. No significant changes in LH and testosterone were observed in this patient group. Eight patients with a normal pretreatment semen analysis provided serial semen samples and two patients showed transient oligospermia with complete recovery by 18 months following treatment. Four patients have fathered normal offspring following radiation therapy. We conclude that low doses (greater than 20 cGy) of scatter irradiation during treatment for Hodgkin's disease can result in transient injury to the seminiferous tubule as manifested by elevations of FSH for 6 to 24 months following treatment. Below 20 cGy, FSH values remained in the normal range. No evidence of Leydig cell injury (using LH and testosterone) was seen in this dose range (up to 70 cGy). Thus, patients with early-stage Hodgkin's disease can be treated with radiation therapy with little to no risk of irreversible testicular injury. Radiation treatment techniques to shield the testes are discussed.

  15. Localization of prestin and expression in the early period after radiation in mice.

    PubMed

    Yang, Chen; Zhang, Wei; Liu, Xiao-Long; Liang, Yong; Yuan, Ya-Wei; Ren, Chen; Peng, Jin-Hao

    2014-12-01

    This study aimed to examine expression and microstructural distribution of prestin in outer hair cells, and the effect of dose and time of radiation on prestin expression in the BALB/c mouse. We also investigated the molecular biological characteristics of prestin and possible mechanisms of sensorineural hearing loss caused by radiation. Seventy 4-week-old mice were randomly divided into four groups, including one control group and three experimental groups. Each experimental group was randomly divided into two groups, which were killed to collect specimens of the cochlea on the 3rd and 7th days after exposure to different doses of 8, 12, and 16 Gy radiation. These cochleas were embedded in paraffin, and then cut into sections. The sections were immunostained with anti-prestin antibodies. The distribution of prestin was observed under optical microscopy and the density of prestin-positive expression was quantitatively calculated by Image-Pro Plus. Prestin had high expression in the lateral membrane and low expression in the cytoplasm of outer hair cells above the nucleus. The density of prestin protein expression of the basal turn was not significantly different after exposure to the different doses of radiation compared with the control group, but up-regulation occurred after radiation in the apex turn. We conclude that prestin protein is mainly expressed in the lateral membrane above the nucleus. Prestin protein may be responsible for the mechanism of injury to the inner ear caused by radiation.

  16. Early post-myocardial infarction survival in MRL mice is mediated by attenuated apoptosis and inflammation but depends on genetic background

    PubMed Central

    Hunt, Darlene L.; Campbell, Patrick H.; Zambon, Alexander C.; Vranizan, Karen; Evans, Sylvia M.; Kuo, Hai-Chien; Yamaguchi, Ken D.; Omens, Jeffrey H.; McCulloch, Andrew D.

    2011-01-01

    The Murphy Roths Large (MRL) mouse, a strain capable of regenerating right ventricular myocardium, has a high post-myocardial infarction (MI) survival rate compared with C57BL/6J (C57) mice. The biological processes responsible for this survival advantage are unknown. To assess the effect of genetic background, the LG/J strain, which harbors 75% of the MRL composite genome, was included in the study. The MRL survival advantage versus C57 mice (92% vs. 68%, P < 0.05) occurred primarily in the first 5 days; LG/J survival was intermediate (P = NS). Microarray data analysis revealed an attenuation of apoptotic (P < 0.05) and stress response transcripts in MRL hearts compared with C57 hearts after MI. Supporting the microarray results, there were fewer TUNEL-positive cells 1 day post-MI in MRL infarcts compared with C57 infarcts (P = 0.001) and fewer CD45-positive cells in the MRL infarct border zone 2 days post-MI (P < 0.01). LG/J results were intermediate (P = NS). MRL hearts had smaller infarct scars and attenuated ventricular dilation 30 days post-MI compared with C57 hearts (P < 0.05). We conclude that the early post-MI survival advantage of MRL mice over the C57 strain is mediated at least in part by reductions in apoptosis and inflammatory infiltration, and that these reductions may influence chronic remodeling. The intermediate survival, apoptosis and inflammation profile of LG/J mice suggests this high tolerance for MI in the MRL could be derived from its shared genetic background with the LG/J. PMID:21967898

  17. Early postmyocardial infarction survival in Murphy Roths Large mice is mediated by attenuated apoptosis and inflammation but depends on genetic background.

    PubMed

    Hunt, Darlene L; Campbell, Patrick H; Zambon, Alexander C; Vranizan, Karen; Evans, Sylvia M; Kuo, Hai-Chien; Yamaguchi, Ken D; Omens, Jeffrey H; McCulloch, Andrew D

    2012-01-01

    The Murphy Roths Large (MRL) mouse, a strain capable of regenerating right ventricular myocardium, has a high postmyocardial infarction (post-MI) survival rate compared with C57BL/6J (C57) mice. The biological processes responsible for this survival advantage are unknown. To assess the effect of genetic background, the LG/J strain, which harbours 75% of the MRL composite genome, was included in the study. The MRL survival advantage versus C57 mice (92 versus 68%, P < 0.05) occurred primarily in the first 5 days; LG/J survival was intermediate (P = n.s.). Microarray data analysis revealed an attenuation of apoptotic (P < 0.05) and stress response transcripts in MRL hearts compared with C57 hearts post-MI. Supporting the microarray results, there were fewer TUNEL-positive cells 1 day post-MI in MRL infarcts compared with C57 infarcts (P = 0.001) and fewer CD45-positive cells in the MRL infarct border zone 2 days post-MI (P < 0.01); the LG/J results were intermediate (P = n.s.). The MRL hearts had smaller infarct scars and attenuated ventricular dilatation 30 days post-MI compared with C57 hearts (P < 0.05). We conclude that the early post-MI survival advantage of MRL mice over the C57 strain is mediated at least in part by reductions in apoptosis and inflammatory infiltration, and that these reductions may influence chronic remodelling. The intermediate survival, apoptosis and inflammation profile of LG/J mice suggests that this high tolerance for MI in the MRL mouse could be derived from its shared genetic background with the LG/J mouse.

  18. 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.

  19. 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.

  20. Rapid Estimation of Macroseismic Intensity for On-site Earthquake Early Warning in Italy from Early Radiated Energ

    NASA Astrophysics Data System (ADS)

    Emolo, A.; Zollo, A.; Brondi, P.; Picozzi, M.; Mucciarelli, M.

    2015-12-01

    Earthquake Early Warning System (EEWS) are effective tools for the risk mitigation in active seismic regions. Recently, a feasibility study of a nation-wide earthquake early warning systems has been conducted for Italy considering the RAN Network and the EEW software platform PRESTo. This work showed that a reliable estimations in terms of magnitude and epicentral localization would be available within 3-4 seconds after the first P-wave arrival. On the other hand, given the RAN's density, a regional EEWS approach would result in a Blind Zone (BZ) of 25-30 km in average. Such BZ dimension would provide lead-times greater than zero only for events having magnitude larger than 6.5. Considering that in Italy also smaller events are capable of generating great losses both in human and economic terms, as dramatically experienced during the recent 2009 L'Aquila (ML 5.9) and 2012 Emilia (ML 5.9) earthquakes, it has become urgent to develop and test on-site approaches. The present study is focused on the development of a new on-site EEW metodology for the estimation of the macroseismic intensity at a target site or area. In this analysis we have used a few thousands of accelerometric traces recorded by RAN related to the largest earthquakes (ML>4) occurred in Italy in the period 1997-2013. The work is focused on the integral EW parameter Squared Velocity Integral (IV2) and on its capability to predict the peak ground velocity PGV and the Housner Intensity IH, as well as from these latters we parameterized a new relation between IV2 and the Macroseismic Intensity. To assess the performance of the developed on-site EEW relation, we used data of the largest events occurred in Italy in the last 6 years recorded by the Osservatorio Sismico delle Strutture, as well as on the recordings of the moderate earthquake reported by INGV Strong Motion Data. The results shows that the macroseismic intensity values predicted by IV2 and the one estimated by PGV and IH are in good agreement.

  1. Induction of transcription of {open_quotes}Immediate early genes{close_quotes} by low-dose ionizing radiation

    SciTech Connect

    Prasad, A.V.; Mohan, N.; Chandrasekar, B.; Meltz, M.L.

    1995-09-01

    The induction of transition of specific genes after exposure to ionizing radiation has previously been reported after lethal doses of radiation (2-50 Gy). Little attention has been focused on expression of {open_quotes}immediate early genes{close_quotes} after low doses of ionizing radiation, where cell viability remains high. This dose range (0.25-2.0 Gy) is above the diagnostic dose level but at or below the doses typical for a single exposure in fractionated radiotherapy treatment of cancer. In this study, it was observed that doses in the range of 0.25-2.0 Gy induced different amounts of the mRNAs of the proto-oncogenes c-fos, c-jun, c-myc and c-Ha-ras at a given dose and time in Epstein-Barr virus-transformed human lymphoblastoid 244B cells. A maximum response was seen after a dose of 0.5 Gy for all but c-fos, which showed a maximum response after exposure to 0.25 Gy. Time-course studies demonstrated that the induction was transient, reaching a maximum at 1 h and declining to the constitutive level at 4 h after irradiation. Using second-messenger specific inhibitors, the signaling pathways involved in the induction of these proto-oncogenes was also investigated. The results showed that all four of the proto-oncogenes induced after 0.5 Gy shared a common pathway of tyrosine kinase activation. Other signaling pathways included protein kinase C, reactive oxygen intermediates and calcium-dependent kinases; these were found to be differentially involved in the induction of transcription of the individual proto-oncogenes. In summary, this study suggests that low-dose ionizing radiation (0.25-2.0 Gy) can modulate expression of immediate early genes. Secondly, the activation of immediate early genes after low-dose exposure involves multiple second-messenger signaling pathways. Third, the magnitude of involvement of the different signaling pathways after low-dose radiation is different for each proto-oncogene expressed. 43 refs., 6 figs., 1 tab.

  2. 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.

  3. Radiative forcing by forest and subsequent feedbacks in the early Eocene climate

    NASA Astrophysics Data System (ADS)

    Port, U.; Claussen, M.; Brovkin, V.

    2015-03-01

    Using the Max Planck Institute for Meteorology Earth System Model, we investigate the forcing of forests and the feedback triggered by forests in the pre-industrial climate and in the early Eocene climate (about 54 to 52 million years ago). Other than the interglacial, pre-industrial climate, the early Eocene climate was characterised by high temperatures which led to almost ice-free poles. We compare simulations in which all continents are covered either by dense forest or by bare soil. To isolate the effect of soil albedo, we choose either bright soils or dark soils, respectively. Considering bright soil, forests warm in both, the early Eocene climate and the current climate, but the warming differs due to differences in climate feedbacks. The lapse-rate and water-vapour feedback is stronger in early Eocene climate than in current climate, but strong and negative cloud feedbacks and cloud masking in the early Eocene climate outweigh the stronger positive lapse-rate and water-vapour feedback. In the sum, global mean warming is weaker in the early Eocene climate. Sea-ice related feedbacks are weak in the almost ice-free climate of the early Eocene leading to a weak polar amplification. Considering dark soil, our results change. Forests cools stronger in the early Eocene climate than in the current climate because the lapse-rate and water-vapour feedback is stronger in the early Eocene climate while cloud feedbacks and cloud masking are equally strong in both climates. The different temperature change by forest in both climates highlights the state-dependency of vegetation's impact on climate.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Radiation Induced Apoptosis of Murine Bone Marrow Cells Is Independent of Early Growth Response 1 (EGR1)

    PubMed Central

    Oben, Karine Z.; Gachuki, Beth W.; Alhakeem, Sara S.; McKenna, Mary K.; Liang, Ying; St. Clair, Daret K.; Rangnekar, Vivek M.; Bondada, Subbarao

    2017-01-01

    An understanding of how each individual 5q chromosome critical deleted region (CDR) gene contributes to malignant transformation would foster the development of much needed targeted therapies for the treatment of therapy related myeloid neoplasms (t-MNs). Early Growth Response 1 (EGR1) is a key transcriptional regulator of myeloid differentiation located within the 5q chromosome CDR that has been shown to regulate HSC (hematopoietic stem cell) quiescence as well as the master regulator of apoptosis—p53. Since resistance to apoptosis is a hallmark of malignant transformation, we investigated the role of EGR1 in apoptosis of bone marrow cells; a cell population from which myeloid malignancies arise. We evaluated radiation induced apoptosis of Egr1+/+ and Egr1-/- bone marrow cells in vitro and in vivo. EGR1 is not required for radiation induced apoptosis of murine bone marrow cells. Neither p53 mRNA (messenger RNA) nor protein expression is regulated by EGR1 in these cells. Radiation induced apoptosis of bone marrow cells by double strand DNA breaks induced p53 activation. These results suggest EGR1 dependent signaling mechanisms do not contribute to aberrant apoptosis of malignant cells in myeloid malignancies. PMID:28081176

  10. The origin of the early differentiation of ivies (Hedera L.) and the radiation of the Asian Palmate group (Araliaceae).

    PubMed

    Valcárcel, Virginia; Fiz-Palacios, Omar; Wen, Jun

    2014-01-01

    The Asian Palmate group is one of the four major clades of the family Araliaceae that is formed by 18 genera, including ivies (Hedera L.). The Mediterranean diversity centre and temperate affinity of ivies contrast with the inferred Asian centre of diversity of the primarily tropical and subtropical Asian Palmate group. We herein investigated the sister-group relationships of Hedera to reconstruct the evolutionary context for its origin and early diversification. Seven nuclear and plastid DNA regions were analyzed in 61 Araliaceae samples including all the 18 Asian Palmate genera. Maximum Parsimony, Maximum Likelihood and Bayesian Inference were run together with a battery of topology testing analyses constraining the expected Hedera's sister-group relationships. Additionally, Bayesian polytomy resolvability and divergence time analyses were also conducted. Genome incongruence and hard nuclear and plastid basal polytomies are detected for the Asian Palmate group where the lineage of Hedera is placed. Topology testing analyses do not allow rejecting any of the tentative sisters of Hedera. An early radiation with inter-lineage hybridization and genome doubling is suggested for the Asian Palmate group where all the seven temperate genera, including Hedera, seem to have played an important role. The radiation took placed during the Upper Cretaceous in Asia under a general cooling and the eastern Asian mountain uplift that produced new temperate environments and promoted lineage connections. This allows us to hypothesize that the origin of the Hedera lineage may fit in a temperate niche conservatism scenario where the combination of the radiation with lineage admixtures prevents us from discovering its sister-group.

  11. Early alterations in extracellular matrix and transforming growth factor [beta] gene expression in mouse lung indicative of late radiation fibrosis

    SciTech Connect

    Finkelstein, J.N.; Johnston, C.J.; Baggs, R.; Rubin, P. )

    1994-02-01

    Fibrosis, characterized by the accumulation of collagen, is a late result of thoracic irradiation. The expression of late radiation injury can be found immediately after irradiation by measuring messenger RNA (mRNA) abundance. To determine if extracellular matrix mRNA and transforming growth factor beta abundance was affected acutely after irradiation, the authors measured mRNA levels of collagen I (CI), collagen III (CIII), collagen IV (CIV), fibronectin (FN), and transforming growth factor [beta] (TGF[beta][sub 1,2 3]) in mouse lungs on day 1 and day 14 after graded doses of radiation. C57BL/6 female mice were irradiated with a single dose to the thorax of 5 or 12.5 Gy. Total lung RNA was prepared and immobilized by Northern and slot blotting and hybridized with radiolabelled cDNA probes for CI, CIII, CIV, FN, TGF[beta][sub 1,2 3] and a control probe encoding for glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Autoradiographic data were quantified by video densitometry and results normalized to GAPDH. Changes in the expression of CI, CIII, CIV, FN and TGF[beta][sub 1,2 3] were observed as early as 1 day after exposure. Through 14 days, changes in mRNA up to 5-fold were seen for any one dose. Dose related changes as high as 10-fold were also evident. The CI:CIII ratio increased gradually for the 5 Gy dose at 14 days postirradiation while the CI:CII ratio for the 12.5 Gy dose decreased by approximately 4-fold as compared to the control. These studies suggest that alterations in expression of extracellular matrix and TGF[beta] mRNA occur very early after radiation injury even at low doses and may play a role in the development of chronic fibrosis. 37 refs., 6 figs.

  12. 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

  13. Early and late radiation-induced skin alterations. Part II: Nursing care of irradiated skin.

    PubMed

    Sitton, E

    1992-07-01

    Teaching patients how to care for irradiated skin during and after a course of radiation therapy is a major concern of oncology nurses. Part I of this two-part article (ONF 19(5):801-807) focused on the mechanisms of skin injury. Many topical preparations are available for skin care. When these substances are applied, both the active ingredient and the vehicle must be appropriate for the condition being treated. Preparations may be applied to the skin as liquids (e.g., lotions, solutions, tinctures used in wet dressings, soaks, baths) or solids (e.g., powders, creams, ointments). As skin reaction progresses during a course of radiation therapy, recommendations for skin care will change. Healing of injury occurs in three stages: inflammation, proliferation, and maturation. Wound healing proceeds more rapidly in a moist environment, and a variety of occlusive dressings can be used with moist desquamation.

  14. [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.

  15. 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.

  16. 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

  17. Combined exposure to ambient UVB radiation and nitrite negatively affects survival of amphibian early life stages.

    PubMed

    Macías, Guadalupe; Marco, Adolfo; Blaustein, Andrew R

    2007-10-15

    Many aquatic species are sensitive to ambient levels of ultraviolet-B radiation (UVB) and chemical fertilizers. However, recent studies indicate that the interaction among multiple stressors acting simultaneously could be contributing to the population declines of some animal species. Therefore, we tested the potential synergistic effects between ambient levels of UVB and a contaminant, sodium nitrite in the larvae of two amphibian species, the common European toad Bufo bufo and the Iberian green frog Rana perezi. We studied R. perezi from both mountain and coastal populations to examine if populations of the same species varied in their response to stressors in different habitats. Both species were sensitive to the two stressors acting alone, but the interaction between the two stressors caused a multiplicative impact on tadpole survival. For B. bufo, the combination of UVB and nitrite was up to seven times more lethal than mortality for each stressor alone. In a coastal wetland, the combination of UVB and nitrite was four times more toxic for R. perezi than the sum of the effect on mortality for each stressor alone. One mg/L of nitrite killed half the population of R. perezi at Gredos Mountains at day 10 in the absence of UVB. In the presence of UVB, 50% of the tadpoles from the same experiment died at day 7. Similar toxic response were found for R. perezi in two highly contrasted environments suggesting this synergistic interaction can be a widespread phenomenon. The interaction of excess chemical fertilizers and manure with ambient UVB radiation could be contributing to the global decline of some amphibian species. We suggest that potential exposure to UVB radiation be accounted for when assessing water quality criteria regarding nitrite pollution.

  18. Intraoperative radiation therapy delivered prior to lumpectomy for early-stage breast cancer: a single institution study

    PubMed Central

    Yu, Wei; Lin, Zhi; Ju, Zhong-Jian; Li, Xi-Ru; Zhang, Yan-Jun; Kong, Qing-Long; Gong, Han-Shun; Wang, Jian-Dong; Ma, Lin

    2015-01-01

    Objective: To evaluate the safety, cosmesis, and clinical outcome of intraoperative electron radiation therapy (IOERT) delivered prior to lumpectomy for early-stage breast cancer. Methods: From December 2008 to March 2012, 75 breast cancer patients (ages 34-66 years) were treated with IOERT during breast conservative surgery. IOERT was delivered using a mobile linear accelerator. Suitable energy and applicator size were chosen to ensure coverage of the tumor with anterior and posterior margins of 1 cm and lateral margins of 2 cm. Patients with sentinel node metastases or younger than 40 years received 8 Gy as boost followed by post-operative external beam radiation therapy of 50 Gy/25F; the others had 15 Gy, prescribed to the 90% isodose depth. Adjuvant treatment consisted of chemotherapy (55 patients), hormonal therapy (59 patients), or combined chemotherapy and hormonal therapy (41 patients). The safety, cosmesis, and short-term outcome were evaluated. Results: Median follow-up was 54 months (range: 30-66 months). Two (2.7%) patients developed post-surgical hematoma. Six (8.0%) patients developed mild breast fibrosis. Eight (10.7%) patients suffered from local pain. One (1.2%) patient experienced a post-operative infection. Sixteen (21.3%) patients developed Grade 1 pulmonary fibrosis. Forty-three (57.3%) patients had an excellent cosmetic result and 23 (30.7%) had a good cosmetic result. Three patients had an ipsilateral breast recurrence, with an actual 3-year local recurrence rate of 4.0%. One patient had an ipsilateral axillary recurrence, resulting in a 3-year regional recurrence rate of 1.3%. No distant metastases or deaths were observed. The 3-year disease free survival was 94.6%. Conclusions: Intraoperative electron radiation therapy delivered prior to lumpectomy is safe and feasible for selected patients with early-stage breast cancer. Early side effects, cosmesis and short-term efficacy are acceptable, but a longer follow-up is needed for evaluation of

  19. 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.

  20. Short-Term Enrollment in Postsecondary Education: Student Background and Institutional Differences in Reasons for Early Departure, 1996-98. Postsecondary Education Descriptive Analysis Reports.

    ERIC Educational Resources Information Center

    Bradburn, Ellen M.

    This report builds on previous studies of early attrition from postsecondary education by providing a more comprehensive look at students' reasons for early total departure from postsecondary education. Using the 1996/1998 Beginning Postsecondary Students Longitudinal Study to examine attrition in the first 3 years of postsecondary education, the…

  1. 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...

  2. 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.].

  3. 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

  4. 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

  5. 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

  6. 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.

  7. 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.

  8. DELAYED EFFECTS OF RADIATION ON THE HUMAN CENTRAL NERVOUS SYSTEM. EARLY AND LATE DELAYED REACTIONS,

    DTIC Science & Technology

    multiple sclerosis and are not associated with degenerative vascular changes. This patient probably represents an extreme of the early delayed reaction reported by Scholz in dogs. There is clinical evidence suggesting that some degree of damage of this type occurs more frequently than has been suspected. The other patient had the late delayed reaction in which there are marked degenerative vascular alternations and severe destruction of the white matter with little cortical involvement. This patient is an extreme example of the well-documented late delayed effects of

  9. [Skin cancer and sun radiation: peruvian experience in the prevention and early detection of skin cancer and melanoma].

    PubMed

    Sordo, Carlos; Gutiérrez, César

    2013-03-01

    The excessive exposure to sun radiation, especially to ultraviolet radiation (UV), has led to various diseases, in particular to skin cancer. In 1995, the Peruvian Dermatological Association conducted the first "Campaign for Education, Prevention and Early Detection of Skin Cancer and Melanoma" called "Mole's Day". The Ministry of Health has turned it into an official event, and the Health Social Security (EsSalud) also participates. This is a free campaign that takes place every year nationwide. 118,092 people attended from 1995 to 2011 in 76 sites distributed in 18 cities throughout the country. A cutaneous lesion were malignancy was suspected was identified in 2.8% of people attending, out of which 64.9% corresponded to basal cell carcinoma, 26.7% to cutaneous melanoma, and 8.4% to squamous cell carcinoma. These campaigns are highly important not only because of the assistance given, but also because of the educational activities aimed at promoting a prevention culture in favor of the most vulnerable populations. Finally, we believe it is important to continue educating the population on skin cancer prevention, to build awareness among the authorities so that they actively participate in the performance of these activities, and to ask all physicians to coordinately join this initiative, in order to continue growing, and to improve all that has been attained for the benefit of our country.

  10. 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.

  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. 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

  13. Early Invasive Cancer and Partial Intraoperative Electron Radiation Therapy of the Breast: Experience of the Jules Bordet Institute

    PubMed Central

    Philippson, C.; Simon, S.; Vandekerkhove, C.; Hertens, D.; Veys, I.; Noterman, D.; De Neubourg, F.; Larsimont, D.; Bourgeois, P.; Van Houtte, P.; Nogaret, J. M.

    2014-01-01

    Objectives. The aim of this prospective phase II study is to evaluate the treatment of early-stage breast cancer (T1 N0) with intraoperative electron radiation therapy (IOERT) in terms of local control, early complications, and cosmesis. Patients and Methods. From February 2010 to February 2012, 200 patients underwent partial IOERT of the breast. Inclusion criteria were unifocal invasive ductal carcinoma, age ≥40 years, histological tumour size ≤20 mm, and no lymph node involvement. A 21 Gy dose was prescribed over the 90% isodose line in the tumour bed. Median follow-up is 23.3 months (7–37). Results. Acute toxicity was not frequent (Grade 1: 4.5%, Grade 2: 1%). The cosmetic result was considered to be very good or good in 92.5%. One ipsi lateral out-quadrant recurrence at 18 months was observed. The crude and actuarial local recurrence rates after median follow-up were 0.5% and 0.9%, respectively. Conclusion. The preoperative diagnostic work-up must be comprehensive and the selection process must be rigorous for this therapeutic approach reserved for small ductal unifocal cancers. After a 23.3-month median follow-up time, the clinical results of IOERT for selected patients are encouraging for the locoregional recurrence and the toxicity rates. The satisfaction of our patients in terms of quality of life was extremely high. PMID:25009747

  14. The GLAST Background Model

    SciTech Connect

    Ormes, J. F.; Atwood, W.; Burnett, T.; Grove, E.; Longo, F.; McEnery, J.; Ritz, S.; Mizuno, T.

    2007-07-12

    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.

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. New Cretaceous marsupial from Mongolia and the early radiation of Metatheria.

    PubMed Central

    Trofimov, B A; Szalay, F S

    1994-01-01

    A marsupial mammal from Mongolia representing a previously unreported group, Asiadelphia, offers unequivocal evidence that metatherians were represented on the continent of Asia during the Late Cretaceous (Campanian), even in the northern arid interior. Asiatherium is known by skull, left and right mandibles, and most of its postcranial skeleton. Comparisons of the dentition, ear region, and aspects of the postcranium not only allow its diagnosis as an Asian group of metatherians but also permit a diagnosis of the Metatheria based on the unequivocally apomorphous condition of the dental formula and probable replacement pattern of the protometatherian, in contrast to the more primitive therian dental formula, represented by the few known Aegialodontidae and the first dental eutherians. It appears an inescapable conclusion that the first metatherians had a more derived dental formula (and probably replacement pattern) than the earliest dental eutherians, regardless of what specific derivation from a therian ancestry is contemplated. Such a diagnosis also supports the metatherian status of other Cretaceous Asian and American taxa such as the Deltatheroida and Kokopellia. The hypothesis that Metatheria originated in North America is largely dependent on the preponderance of Cretaceous forms from North America and negative evidence from Asia (i.e., on the lack of lower latitude Early Cretaceous tropical faunas). Conversely, the relative Cretaceous paucity of placentals from North America and their greater abundance in Asia suggests the earliest flowering of the Eutheria in an unspecified region of the Old World. The concept of a holophyletic Theria (= Tribosphenida) employed here, based on the biologically significant apomorphy of the molar form-function of the first therian, entails only the tribosphenic mammals (infraclasses Tribotheria, Metatheria, and Eutheria) but not the sundry quasi-triangular-toothed mammals and their derivatives in the Mesozoic (Eupantotheria

  8. 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

  9. 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.

  10. Effects of argon laser radiation on aortic endothelial cells: Early membrane changes and proliferative response

    SciTech Connect

    Franceschi, D.; Graham, D.; Alexander, J.J.; Koehler, K. )

    1989-06-01

    Membrane fluidity, transmembrane signaling responses, and proliferative characteristics of endothelial cells were studied to characterize biochemical and molecular changes after treatment with argon laser energy. Bovine aortic endothelial cells grown in monolayers were irradiated at 50, 100, and 200 J with an argon laser (wavelength, 488 and 514 nm). Proliferation, assayed by ({sup }3H)thymidine incorporation, was measured daily for 6 days. An initial lag phase was observed for irradiated cells when compared to nonirradiated controls (P less than 0.03), with eventual recovery by the third day. Membrane fluidity, determined by fluorescence anisotropy, was measured 1 hr after irradiation. A decrease in static rotational motion of 1,6-diphenyl-1,3,5-hexatriene (DPH) was noted in irradiated versus nonirradiated cells indicating a decrease in membrane fluidity (P less than 0.02). Dynamic studies of intracellular calcium and pH flux utilizing fluorescent probes demonstrated a preserved response to mitogenic stimulation. An increase in intracellular Ca2+ with a concomitant alkalinization of the intracellular milieu was observed in irradiated and non-irradiated cells in response to stimulation with endothelial cell growth factor (ECGF). These responses resemble those characterized for other mitogens. Argon laser energy applied to aortic endothelial cells decreases membrane fluidity early after irradiation. These alterations probably cause the initial lag observed in their proliferative response; however, the capacity to respond to exogenous mitogenic stimulation is maintained.

  11. 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.

  12. Programmed Ventricular Stimulation to Risk Stratify for Early Cardioverter-Defibrillator Implantation to Prevent Tachyarrhythmias following Acute Myocardial Infarction (PROTECT-ICD): Trial Protocol, Background and Significance.

    PubMed

    Zaman, Sarah; Taylor, Andrew J; Stiles, Martin; Chow, Clara; Kovoor, Pramesh

    2016-11-01

    The 'Programmed Ventricular Stimulation to Risk Stratify for Early Cardioverter-Defibrillator Implantation to Prevent Tachyarrhythmias following Acute Myocardial Infarction' (PROTECT-ICD) trial is an Australian-led multicentre randomised controlled trial targeting prevention of sudden cardiac death in patients who have at least moderately reduced cardiac function following a myocardial infarct (MI). The primary objective of the trial is to assess whether electrophysiological study to guide prophylactic implantation of an implantable cardioverter-defibrillator (ICD) early following MI (first 40 days) will lead to a significant reduction in sudden cardiac death and non-fatal arrhythmia. The secondary objective is to assess the utility of cardiac MRI (CMR) in assessing early myocardial characteristics, and its predictive value for both inducible ventricular tachycardia (VT) at EPS and SCD/ non-fatal arrhythmia at follow-up.

  13. Early radiation-induced endothelial cell loss and blood-spinal cord barrier breakdown in the rat spinal cord.

    PubMed

    Li, Yu-Qing; Chen, Paul; Jain, Vipan; Reilly, Raymond M; Wong, C Shun

    2004-02-01

    Using a rat spinal cord model, this study was designed to characterize radiation-induced vascular endothelial cell loss and its relationship to early blood-brain barrier disruption in the central nervous system. Adult rats were given a single dose of 0, 2, 8, 19.5, 22, 30 or 50 Gy to the cervical spinal cord. At various times up to 2 weeks after irradiation, the spinal cord was processed for histological and immunohistochemical analysis. Radiation-induced apoptosis was assessed by morphology and TdT-mediated dUTP nick end labeling combined with immunohistochemical markers for endothelial and glial cells. Image analysis was performed to determine endothelial cell and microvessel density using immunohistochemistry with endothelial markers, namely endothelial barrier antigen, glucose transporter isoform 1, laminin and zonula occludens 1. Blood-spinal cord barrier permeability was assessed using immunohistochemistry for albumin and (99m)Tc-diethylenetriamine pentaacetic acid as a vascular tracer. Endothelial cell proliferation was assessed using in vivo BrdU labeling. During the first 24 h after irradiation, apoptotic endothelial cells were observed in the rat spinal cord. The decrease in endothelial cell density at 24 h after irradiation was associated with an increase in albumin immunostaining around microvessels. The decrease in the number of endothelial cells persisted for 7 days and recovery of endothelial density was apparent by day 14. A similar pattern of blood-spinal cord barrier disruption and recovery of permeability was observed over the 2 weeks, and an increase in BrdU-labeled endothelial cells was seen at day 3. These results are consistent with an association between endothelial cell death and acute blood-spinal cord barrier disruption in the rat spinal cord after irradiation.

  14. 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.

  15. 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.

  16. Pathogenetic validation of the use of biological protective agents and early treatment in cases of radiation injury simulating radiation effects under space flight conditions

    NASA Technical Reports Server (NTRS)

    Rogozkin, V. D.; Varteres, V.; Sabo, L.; Groza, N.; Nikolov, I.

    1974-01-01

    In considering a radiation safety system for space flights, the various measures to protect man against radiation include drug prophylaxis. At the present time a great deal of experimental material has been accumulated on the prevention and treatment of radiation injuries. Antiradiation effectiveness has been established for sulfur- and nitrogen-containing substances, auxins, cyanides, polynucleotides, mucopolysaccharides, lipopolysaccharides, aminosaccharides, synthetic polymers, vitamins, hormones, amino acids and other compounds which can be divided into two basic groups - biological and chemical protective agents.

  17. 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…

  18. Early-Stage Breast Cancer Treated With 3-Week Accelerated Whole-Breast Radiation Therapy and Concomitant Boost

    SciTech Connect

    Chadha, Manjeet; Woode, Rudolph; Sillanpaa, Jussi; Lucido, David; Boolbol, Susan K.; Kirstein, Laurie; Osborne, Michael P.; Feldman, Sheldon; Harrison, Louis B.

    2013-05-01

    Purpose: To report early outcomes of accelerated whole-breast radiation therapy with concomitant boost. Methods and Materials: This is a prospective, institutional review board-approved study. Eligibility included stage TisN0, T1N0, and T2N0 breast cancer. Patients receiving adjuvant chemotherapy were ineligible. The whole breast received 40.5 Gy in 2.7-Gy fractions with a concomitant lumpectomy boost of 4.5 Gy in 0.3-Gy fractions. Total dose to the lumpectomy site was 45 Gy in 15 fractions over 19 days. Results: Between October 2004 and December 2010, 160 patients were treated; stage distribution was as follows: TisN0, n=63; T1N0, n=88; and T2N0, n=9. With a median follow-up of 3.5 years (range, 1.5-7.8 years) the 5-year overall survival and disease-free survival rates were 90% (95% confidence interval [CI] 0.84-0.94) and 97% (95% CI 0.93-0.99), respectively. Five-year local relapse-free survival was 99% (95% CI 0.96-0.99). Acute National Cancer Institute/Common Toxicity Criteria grade 1 and 2 skin toxicity was observed in 70% and 5%, respectively. Among the patients with ≥2-year follow-up no toxicity higher than grade 2 on the Late Effects in Normal Tissues–Subjective, Objective, Management, and Analytic scale was observed. Review of the radiation therapy dose–volume histogram noted that ≥95% of the prescribed dose encompassed the lumpectomy target volume in >95% of plans. The median dose received by the heart D{sub 05} was 215 cGy, and median lung V{sub 20} was 7.6%. Conclusions: The prescribed accelerated schedule of whole-breast radiation therapy with concomitant boost can be administered, achieving acceptable dose distribution. With follow-up to date, the results are encouraging and suggest minimal side effects and excellent local control.

  19. Impact of Adjuvant External-Beam Radiation Therapy in Early-Stage Uterine Papillary Serous and Clear Cell Carcinoma

    SciTech Connect

    Kim, Anne; Schreiber, David; Rineer, Justin; Choi, Kwang; Rotman, Marvin

    2011-11-15

    Purpose: Adjuvant radiation therapy (RT) in early-stage high- to intermediate-risk endometrioid adenocarcinoma is well established and has been shown to improve locoregional control. Its role in the management of early-stage clear cell carcinoma and uterine papillary serous carcinoma (UPSC) remains controversial. Methods and Materials: Using the Surveillance Epidemiology and End Results database, we identified women with American Joint Committee on Cancer Stage Sixth Edition. Stage IA-IIB clear cell carcinoma or UPSC who underwent hysterectomy with or without adjuvant RT between 1988 and 2003. We used Kaplan-Meier and Cox regression analysis to compare overall survival (OS) for all patients. Results: We identified 1,333 women of whom 451 had clear cell carcinoma and 882 had UPSC. Of those patients, 775 underwent surgery alone and 558 received adjuvant RT as well. For Stages I-IIB disease, the median OS with surgery alone was 106 months, vs. 151 months with adjuvant RT (p = 0.006). On subgroup analysis, we saw the benefit from adjuvant RT only in Stage IB-C patients. For Stage IB disease, patients undergoing surgery alone had a median OS of 117 months, vs. median survival not reached with the addition of RT (p = 0.006). For Stage IC disease, surgery alone had a median OS of 35 months vs. 120 months with RT (p = 0.001). Although the apparent benefit of RT diminished when measured via multivariate analysis, the impact of RT on survival did show a trend toward significance (hazard ration 0.808, confidence interval 95% 0.651-1.002, p = 0.052) Conclusion: In FIGO Stage IB-C papillary serous and clear cell uterine carcinoma, adjuvant RT seems to play an important role in improving survival.

  20. 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

    Very sensitive detectors are used for low-background applications including the detection of environmental radioactivity, double-beta decay, and dark matter. In order to reduce the background noise enough to utilize the sensitivity of these detectors, lead with little or no alpha activity is required to form the shielding. In the past, antiquity lead shielding was used for low-background detectors because lead’s most prominent alpha-emitting isotope, 210Pb, has a short half-life. The microelectronics industry is also greatly affected by alpha activity in lead and solder, and has begun producing “clean” lead for purchase. To quantify how clean the available lead is, 210Pb and, during procedural experiments, a 209Po tracer must be physically or chemically removed from the bulk lead. A reliable procedure for chemical separations that does not use large volumes of ultra-high-purity chemicals has not yet been established. Lead was dissolved and a known amount of 209Po tracer was added. The samples were put through each of two new procedures. The first procedure was based on complete dissolution of the lead followed by a column separation. The second method investigates the utility of a pre-separation step using precipitation of the lead prior to column separation. The resulting solutions were run through strontium resin columns from Eichrom Inc., a United States Transuranium and Uranium Registries (USTUR) electrodeposition procedure, and scheduled to be alpha counted for a minimum of three days. Though neither of the tested procedures had acceptable logistics for large scale implementation, later alpha counting will show which procedure is more promising for further development

  1. Radiation-induced second malignancies after involved-node radiotherapy with deep-inspiration breath-hold technique for early stage Hodgkin Lymphoma: a dosimetric study

    PubMed Central

    2014-01-01

    Background To estimate the risk of radiation induced second cancers after radiotherapy using deep-inspiration breath-hold (DI) technique with three-dimensional conformal (3DCRT) and volumetric arc therapy (VMAT) for patients with Hodgkin’s lymphoma (HL). Methods Early-stage HL with mediastinal and supraclavicular involvement was studied using an Alderson phantom. A whole body CT was performed and all tissues were delineated. The clinical target volumes and planning target volumes (PTV) were determined according to the German Hodgkin study group guidelines. Free-breathing (FB) technique and DI technique were simulated by different safety margins for the PTV definition. In both cases, 30 Gy in 15 fractions was prescribed. Second cancer risk was estimated for various tissues with a second cancer model including fractionation. Results When compared with FB-3DCRT, estimated relative life time attributable risk (LAR) of cancer induction after DI-3DCRT was 0.86, 0.76, 0.94 and 0.92 for breast, lung, esophagus and stomach, respectively. With DI-VMAT, the corresponding values were 2.05, 1.29, 1.01, 0.93, respectively. For breast cancer, the LAR observed with DI-VMAT was not substantially distinguishable from the LAR computed for mantle RT with an administered dose of 40 Gy. Conclusions This study suggests that DI may reduce the LAR of secondary cancers of all OARs and may be a valuable technique when using 3DCRT. Conversely, VMAT may increase substantially the LAR and should be cautiously implemented in clinical practice. PMID:24548307

  2. LiteBIRD: lite satellite for the study of B-mode polarization and inflation from cosmic microwave background radiation detection

    NASA Astrophysics Data System (ADS)

    Ishino, H.; Akiba, Y.; Arnold, K.; Barron, D.; Borrill, J.; Chendra, R.; Chinone, Y.; Cho, S.; Cukierman, A.; de Haan, T.; Dobbs, M.; Dominjon, A.; Dotani, T.; Elleflot, T.; Errard, J.; Fujino, T.; Fuke, H.; Funaki, T.; Goeckner-Wald, N.; Halverson, N.; Harvey, P.; Hasebe, T.; Hasegawa, M.; Hattori, K.; Hattori, M.; Hazumi, M.; Hidehira, N.; Hill, C.; Hilton, G.; Holzapfel, W.; Hori, Y.; Hubmayr, J.; Ichiki, K.; Imada, H.; Inatani, J.; Inoue, M.; Inoue, Y.; Irie, F.; Irwin, K.; Ishitsuka, H.; Jeong, O.; Kanai, H.; Karatsu, K.; Kashima, S.; Katayama, N.; Kawano, I.; Kawasaki, T.; Keating, B.; Kernasovskiy, S.; Keskitalo, R.; Kibayashi, A.; Kida, Y.; Kimura, N.; Kimura, K.; Kisner, T.; Kohri, K.; Komatsu, E.; Komatsu, K.; Kuo, C.-L.; Kuromiya, S.; Kusaka, A.; Lee, A.; Li, D.; Linder, E.; Maki, M.; Matsuhara, H.; Matsumura, T.; Matsuoka, S.; Matsuura, S.; Mima, S.; Minami, Y.; Mitsuda, K.; Nagai, M.; Nagasaki, T.; Nagata, R.; Nakajima, M.; Nakamura, S.; Namikawa, T.; Naruse, M.; Nishibori, T.; Nishijo, K.; Nishino, H.; Noda, A.; Noguchi, T.; Ogawa, H.; Ogburn, W.; Oguri, S.; Ohta, I.; Okada, N.; Okamoto, A.; Okamura, T.; Otani, C.; Pisano, G.; Rebeiz, G.; Richards, P.; Sakai, S.; Sakurai, Y.; Sato, Y.; Sato, N.; Segawa, Y.; Sekiguchi, S.; Sekimoto, Y.; Sekine, M.; Seljak, U.; Sherwin, B.; Shimizu, T.; Shinozaki, K.; Shu, S.; Stompor, R.; Sugai, H.; Sugita, H.; Suzuki, J.; Suzuki, T.; Suzuki, A.; Tajima, O.; Takada, S.; Takakura, S.; Takano, K.; Takatori, S.; Takei, Y.; Tanabe, D.; Tomaru, T.; Tomita, N.; Turin, P.; Uozumi, S.; Utsunomiya, S.; Uzawa, Y.; Wada, T.; Watanabe, H.; Westbrook, B.; Whitehorn, N.; Yamada, Y.; Yamamoto, R.; Yamasaki, N.; Yamashita, T.; Yoshida, T.; Yoshida, M.; Yotsumoto, K.

    2016-07-01

    LiteBIRD is a next generation satellite aiming for the detection of the Cosmic Microwave Background (CMB) B-mode polarization imprinted by the primordial gravitational waves generated in the era of the inflationary universe. The science goal of LiteBIRD is to measure the tensor-to-scaler ratio r with a precision of δr < 10-3♢, offering us a crucial test of the major large-single-field slow-roll inflation models. LiteBIRD is planned to conduct an all sky survey at the sun-earth second Lagrange point (L2) with an angular resolution of about 0.5 degrees to cover the multipole moment range of 2 <= l <= 200. We use focal plane detector arrays consisting of 2276 superconducting detectors to measure the frequency range from 40 to 400 GHz with the sensitivity of 3.2 μK·arcmin. including the ongoing studies.

  3. Ingestion dose from 238U, 232Th, 226Ra, 40K and 137Cs in cereals, pulses and drinking water to adult population in a high background radiation area, Odisha, India.

    PubMed

    Lenka, Pradyumna; Sahoo, S K; Mohapatra, S; Patra, A C; Dubey, J S; Vidyasagar, D; Tripathi, R M; Puranik, V D

    2013-03-01

    A natural high background radiation area is located in Chhatrapur, Odisha in the eastern part of India. The inhabitants of this area are exposed to external radiation levels higher than the global average background values, due to the presence of uranium, thorium and its decay products in the monazite sands bearing placer deposits in its beaches. The concentrations of (232)Th, (238)U, (226)Ra, (40)K and (137)Cs were determined in cereals (rice and wheat), pulses and drinking water consumed by the population residing around this region and the corresponding annual ingestion dose was calculated. The annual ingestion doses from cereals, pulses and drinking water varied in the range of 109.4-936.8, 10.2-307.5 and 0.5-2.8 µSv y(-1), respectively. The estimated total annual average effective dose due to the ingestion of these radionuclides in cereals, pulses and drinking water was 530 µSv y(-1). The ingestion dose from cereals was the highest mainly due to a high consumption rate. The highest contribution of dose was found to be from (226)Ra for cereals and drinking water and (40)K was the major dose contributor from the intake of pulses. The contribution of man-made radionuclide (137)Cs to the total dose was found to be minimum. (226)Ra was found to be the largest contributor to ingestion dose from all sources.

  4. Threshold segmentation for PET target volume delineation in radiation treatment planning: the role of target-to-background ratio and target size.

    PubMed

    Brambilla, M; Matheoud, R; Secco, C; Loi, G; Krengli, M; Inglese, E

    2008-04-01

    A multivariable approach was adopted to study the dependence of the percentage threshold [TH(%)] used to define the boundaries of 18F-FDG positive tissue on emission scan duration (ESD) and activity at the start of acquisition (Aacq) for different target sizes and target-to-background (T/B) ratios. An anthropomorphic model, at least for counting rate characteristics, was used to study this dependence in conditions resembling the ones that can be encountered in the clinical studies. An annular ring of water bags of 3 cm thickness was fitted over an International Electro-technical Commission (IEC) phantom in order to obtain counting rates similar to those found in average patients. The scatter fraction of the modified IEC phantom was similar to the mean scatter fraction measured on patients, with a similar scanner. A supplemental set of microhollow spheres was positioned inside the phantom. The NEMA NU 2-2001 scatter phantom was positioned at the end of the IEC phantom to approximate the clinical situation of having activity that extends beyond the scanner field of view. The phantoms were filled with a solution of water and 18F (12 kBq/mL) and the spheres with various T/B ratios of 22.5, 10.3, and 3.6. Sequential imaging was performed to acquire PET images with varying background activity concentrations of about 12, 9, 6.4, 5.3, and 3.1 kBq/mL. The ESD was set to 60, 120, 180, and 240 s/bed. Data were fitted using two distinct multiple linear regression models for sphere ID < or = 10 mm and sphere ID > 10 mm. The fittings of both models were good with an R2 of 0.86 in both cases. Neither ESD nor Aacq resulted as significant predictors of the TH(%). For sphere ID < or =10 mm the target size was the most significant predictor of the TH(%), followed by the T/B ratio, while for sphere ID > 10 mm the explanatory power of the target size and T/B ratio were reversed, the T/B ratio being now the most important predictor of the TH(%). Both the target size and T/B ratio play a

  5. Inhaled /sup 147/Pm and/or total-body gamma radiation: Early mortality and morbidity in rats

    SciTech Connect

    Filipy, R.E.; Lauhala, K.E.; McGee, D.R.; Cannon, W.C.; Buschbom, R.L.; Decker, J.R.; Kuffel, E.G.; Park, J.F.; Ragan, H.A.; Yaniv, S.S.; Scott, B.R.

    1989-05-01

    Rats were given doses of /sup 60/Co gamma radiation and/or lung burdens of /sup 147/Pm (in fused aluminosilicate particles) within lethal ranges in an experiment to determine and compare morbidity and mortality responses for the radiation insults within 1 year after exposure. Radiation-induced morbidity was assessed by measuring changes in body weights, hematologic parameters, and pulmonary-function parameters. Acute mortality and morbidity from inhaled promethium were caused primarily by radiation pneumonitis and pulmonary fibrosis that occurred more than 53 days after exposure. Acute mortality and morbidity from total-body gamma irradiation occurred within 30 days of exposure and resulted from the bone-marrow radiation syndrome. Gamma radiation caused transient morbidity, reflected by immediately depressed blood cell levels and by reduced body weight gain in animals that survived the acute gamma radiation syndrome. Inhaled promethium caused a loss of body weight and diminished pulmonary function, but its only effect on blood cell levels was lymphocytopenia. Combined gamma irradiation and promethium lung burdens were synergistic, in that animals receiving both radiation insults had higher morbidity and mortality rates than would be predicted based on the effect of either kind of radiation alone. Promethium lung burdens enhanced the effect of gamma radiation in rats within the first 30 days of exposure, and gamma radiation enhanced the later effect of promethium lung burdens. 70 refs., 68 figs., 21 tabs.

  6. An interactive ontology-driven information system for simulating background radiation and generating scenarios for testing special nuclear materials detection algorithms

    DOE PAGES

    Sorokine, Alexandre; Schlicher, Bob G.; Ward, Richard C.; ...

    2015-05-22

    This paper describes an original approach to generating scenarios for the purpose of testing the algorithms used to detect special nuclear materials (SNM) that incorporates the use of ontologies. Separating the signal of SNM from the background requires sophisticated algorithms. To assist in developing such algorithms, there is a need for scenarios that capture a very wide range of variables affecting the detection process, depending on the type of detector being used. To provide such a cpability, we developed an ontology-driven information system (ODIS) for generating scenarios that can be used in creating scenarios for testing of algorithms for SNMmore » detection. The ontology-driven scenario generator (ODSG) is an ODIS based on information supplied by subject matter experts and other documentation. The details of the creation of the ontology, the development of the ontology-driven information system, and the design of the web user interface (UI) are presented along with specific examples of scenarios generated using the ODSG. We demonstrate that the paradigm behind the ODSG is capable of addressing the problem of semantic complexity at both the user and developer levels. Compared to traditional approaches, an ODIS provides benefits such as faithful representation of the users' domain conceptualization, simplified management of very large and semantically diverse datasets, and the ability to handle frequent changes to the application and the UI. Furthermore, the approach makes possible the generation of a much larger number of specific scenarios based on limited user-supplied information« less

  7. Measurements of anisotropy in the cosmic microwave background radiation at degree angular scales near the stars Sigma Herculis and Iota Draconis

    NASA Technical Reports Server (NTRS)

    Clapp, A. C.; Devlin, M. J.; Gundersen, J. O.; Hagmann, C. A.; Hristov, V. V.; Lange, A. E.; Lim, M.; Lubin, P. M.; Mauskopf, P. D.; Meinhold, P. R.

    1994-01-01

    We present results from two four-frequency observations centered near the stars Sigma Herculis and Iota Draconis during the fourth flight of the Millimeter-wave Anisotropy eXperiment (MAX). The observations were made of 6 deg x 0.6 deg strips of the sky with a 1.4 deg peak to peak sinusoidal chop in all bands. The full width at half maximum (FWHM) beam sizes were calculated 0.55 deg +/- 0.05 deg at 3.5/cm and a 0.75 deg +/- 0.05 deg at 6, 9, and 14/cm. Significant correlated structures were observed at 3.5, 6, and 9/cm. The spectra of these signals are inconsistent with thermal emission from known interstellar dust populations. The extrapolated amplitudes of synchrotron and free-free emission are too small to account for the amplitude of the observed structures. If the observed structures are attributed to cosmic microwave background (CMB) anisotropy with a Gaussian autocorrelation function and a coherence angle of 25 min, then the most probable values at Delta T/T(sub CMB) = 3.1 (sup +1.7 sub -1.3) x 10(exp -5) for the Sigma Herculis scan, and Delta T/T(sub CMB) = 3.3(sup +1.1 sub -1.1) x 10(exp -5) for the Iota Draconis scan (95% confidence upper, lower limits).

  8. An interactive ontology-driven information system for simulating background radiation and generating scenarios for testing special nuclear materials detection algorithms

    SciTech Connect

    Sorokine, Alexandre; Schlicher, Bob G.; Ward, Richard C.; Wright, Michael C.; Kruse, Kara L.; Bhaduri, Budhendra; Slepoy, Alexander

    2015-05-22

    This paper describes an original approach to generating scenarios for the purpose of testing the algorithms used to detect special nuclear materials (SNM) that incorporates the use of ontologies. Separating the signal of SNM from the background requires sophisticated algorithms. To assist in developing such algorithms, there is a need for scenarios that capture a very wide range of variables affecting the detection process, depending on the type of detector being used. To provide such a cpability, we developed an ontology-driven information system (ODIS) for generating scenarios that can be used in creating scenarios for testing of algorithms for SNM detection. The ontology-driven scenario generator (ODSG) is an ODIS based on information supplied by subject matter experts and other documentation. The details of the creation of the ontology, the development of the ontology-driven information system, and the design of the web user interface (UI) are presented along with specific examples of scenarios generated using the ODSG. We demonstrate that the paradigm behind the ODSG is capable of addressing the problem of semantic complexity at both the user and developer levels. Compared to traditional approaches, an ODIS provides benefits such as faithful representation of the users' domain conceptualization, simplified management of very large and semantically diverse datasets, and the ability to handle frequent changes to the application and the UI. Furthermore, the approach makes possible the generation of a much larger number of specific scenarios based on limited user-supplied information

  9. Spatial and vertical distributions of heavy metals and their potential toxicity levels in various beach sediments from high-background-radiation area, Kerala, India.

    PubMed

    Suresh, G; Ramasamy, V; Sundarrajan, M; Paramasivam, K

    2015-02-15

    The spatial and vertical distribution of heavy metals and the sediment characteristics of beaches in Kerala, India (the upper surface sediments and the first, second and third one-foot-thick strata) were assessed in this study. The concentrations of most of the studied metals were highest at sampling site S1 (Cochin). The measured concentrations were compared with background and toxicological reference values. The results show that definite adverse biological effects are possible at most of the sampling sites due to the high Pb levels. Three different indexes were calculated to investigate the potential toxicity level. Most of the studied metals and all calculated indexes were highest in the third foot of sediment. Multivariate statistical analyses were performed and suggested that particular heavy metals, e.g., Pb, Cd, Cr and Ni, may represent contamination from a common source. The Cd and Pb concentrations and all the calculated index values show a relationship with the content of organic matter. The results of the present study suggest the recommendation that a systematic analysis is needed to monitor heavy metal levels in the studied area.

  10. Population genetic analyses of Hypoplectrus coral reef fishes provide evidence that local processes are operating during the early stages of marine adaptive radiations.

    PubMed

    Puebla, Oscar; Bermingham, Eldredge; Guichard, Frédéric

    2008-03-01

    Large-scale, spatially explicit models of adaptive radiation suggest that the spatial genetic structure within a species sampled early in the evolutionary history of an adaptive radiation might be higher than the genetic differentiation between different species formed during the same radiation over all locations. Here we test this hypothesis with a spatial population genetic analysis of Hypoplectrus coral reef fishes (Serranidae), one of the few potential cases of a recent adaptive radiation documented in the marine realm. Microsatellite analyses of Hypoplectrus puella (barred hamlet) and Hypoplectrus nigricans (black hamlet) from Belize, Panama and Barbados validate the population genetic predictions at the regional scale for H. nigricans despite the potential for high levels of gene flow between populations resulting from the 3-week planktonic larval phase of Hypoplectrus. The results are different for H. puella, which is characterized by significantly lower levels of spatial genetic structure than H. nigricans. An extensive field survey of Hypoplectrus population densities complemented by individual-based simulations shows that the higher abundance and more continuous distribution of H. puella could account for the reduced spatial genetic structure within this species. The genetic and demographic data are also consistent with the hypothesis that H. puella might represent the ancestral form of the Hypoplectrus radiation, and that H. nigricans might have evolved repeatedly from H. puella through ecological speciation. Altogether, spatial genetic analysis within and between Hypoplectrus species indicate that local processes can operate at a regional scale within recent marine adaptive radiations.

  11. Impact of Pretreatment Tumor Growth Rate on Outcome of Early-Stage Lung Cancer Treated With Stereotactic Body Radiation Therapy

    SciTech Connect

    Atallah, Soha; Cho, B.C. John; Allibhai, Zishan; Taremi, Mojgan; Giuliani, Meredith; Le, Lisa W.; Brade, Anthony; Sun, Alexander; Bezjak, Andrea; Hope, Andrew J.

    2014-07-01

    Purpose: To determine the influence of pretreatment tumor growth rate on outcomes in patients with early-stage non-small cell lung cancer (NSCLC) treated with stereotactic body radiation therapy (SBRT). Methods and Materials: A review was conducted on 160 patients with T1-T2N0M0 NSCLC treated with SBRT at single institution. The patient's demographic and clinical data, time interval (t) between diagnostic and planning computed tomography (CT), vital status, disease status, and cause of death were extracted from a prospectively kept database. Differences in gross tumor volume between diagnostic CT (GTV1) and planning CT (GTV2) were recorded, and growth rate was calculated by use of specific growth rate (SGR). Kaplan-Meier curves were constructed for overall survival (OS). Differences between groups were compared with a log-rank test. Multivariate analyses were performed by use of the Cox proportional hazard model with SGR and other relevant clinical factors. Cumulative incidence was calculated for local, regional, and distant failures by use of the competing risk approach and was compared with Gray's test. Results: The median time interval between diagnostic and planning CT was 82 days. The patients were divided into 2 groups, and the median SGR was used as a cut-off. The median survival times were 38.6 and 27.7 months for the low and high SGR groups, respectively (P=.03). Eastern Cooperative Oncology Group performance status (P=.01), sex (P=.04), SGR (P=.03), and GTV2 (P=.002) were predictive for OS in multivariable Cox regression analysis and, except sex, were similarly predictive for failure-free survival (FFS). The 3-year cumulative incidences of regional failure were 19.2% and 6.0% for the high and low SGR groups, respectively (P=.047). Conclusion: High SGR was correlated with both poorer OS and FFS in patients with early-stage NSCLC treated with SBRT. If validated, this measurement may be useful in identifying patients most likely to benefit from adjuvant

  12. Measurements of anisotropy in the cosmic microwave background radiation at 0.5 deg angular scales near the star gamma ursae minoris

    NASA Technical Reports Server (NTRS)

    Devlin, M. J.; Clapp, A. C.; Gundersen, J. O.; Hagmann, C. A.; Hristov, V. V.; Lange, A. E.; Lim, M. A.; Lubin, P. M.; Mauskopf, P. D.; Meinhold, P. R.

    1994-01-01

    We present results from a four-frequency observation of a 6 deg x 0.6 deg strip of the sky centered near the star Gamma Ursae Minoris (GUM) during the fourth flight of the Millimeter-wave Anistropy experiment(MAX). The observation was made with a 1.4 deg peak-to-peak sinusoidal chop in all bands. The FWHM beam sizes were 0.55 deg +/- 0.05 deg at 3.5 per cm and 0.75 deg +/- 0.05 deg at 6, 9, and 14 per cm. During this observation significant correlated structure was observed at 3.5, 6 and 9 per cm with amplitudes similar to those observed in the GUM region during the second and third fligts of MAX. The frequency spectrum is consistent with cosmic microwave background (CMB) and inconsistent with thermal emission from interstellar dust. The extrapolated amplitudes of synchrotron and free-free emission are too small to account for the amplitude of the observed structure, If all of the structure is attributed to CMB anisotropy with a Gaussian autocorrelation function and a coherence angle of 25 min, then the most probable values of delta T/T(sub CMB) in the 3.5, 6 and 9 per cm bads are (4.3 +2.7/-1.6) x 10(exp -5), 2.8 (+4.3/-1/1) x 10(exp -5), and 3.5 (+3.0/-1.6) x 10(exp -5) (95% confidence upper and lower limits), respectively.

  13. A search for a keV signature of radiatively decaying dark matter with Suzaku XIS observations of the X-ray diffuse background

    NASA Astrophysics Data System (ADS)

    Sekiya, Norio; Yamasaki, Noriko Y.; Mitsuda, Kazuhisa

    2016-06-01

    We performed the deepest search for an X-ray emission line at between 0.5 and 7 keV from non-baryonic dark matter by the Suzaku XIS. Dark matter associated with the Milky Way was selected as the target to obtain the best signal-to-noise ratio. From the Suzaku archive, we selected 187 data sets of blank-sky regions that were dominated by the X-ray diffuse background. The data sets were from 2005 to 2013. The instrumental responses were adjusted by multiple calibration data sets of the Crab Nebula. We also improved the technique of subtracting lines of instrumental origin. These energy spectra were well described by X-ray emission due to charge exchange around the Solar System, hot plasma in and around the Milky Way, and the superposition of extra-galactic point sources. A signal of a narrow emission-line was searched for, and the significance of detection was evaluated in consideration of the blind search method (the Look-elsewhere Effect). Our results exhibited no significant detection of an emission line feature from dark matter. The 3 σ upper limit for the emission line intensity between 1 and 7 keV was ˜ 10-2 photons cm-2 s-1 sr-1, or ˜ 5 × 10-4 photons cm-2 s-1 sr-1 per M⊙ pc-2, assuming a dark matter distribution with the Galactic rotation curve. The parameters of sterile neutrinos as candidates of dark-matter were also constrained.

  14. The microwave background anisotropies: Observations

    PubMed Central

    Wilkinson, David

    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 μK 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° 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. PMID:9419320

  15. Interstitial radiation therapy for early-stage nasal vestibule cancer: A continuing quest for optimal tumor control and cosmesis

    SciTech Connect

    Levendag, Peter C. . E-mail: p.levendag@erasmusmc.nl; Nijdam, Wideke M.; Moolenburgh, Sanne E. van; Tan, Lisa; Noever, Inge R.T.T.; Rooy, Peter van; Mureau, Marc; Jansen, Peter P.; Munte, Kai; Hofer, Stefan O.P.

    2006-09-01

    Introduction: This article reports on the effectiveness, cosmetic outcome, and costs of interstitial high-dose-rate (HDR) brachytherapy for early-stage cancer of the nasal vestibule (NV) proper and/or columella high-dose-rate (HDR). Methods and Materials: Tumor control, survival, cosmetic outcome, functional results, and costs were established in 64 T1/T2N0 nasal vestibule cancers treated from 1991-2005 by fractionated interstitial radiation therapy (IRT) only. Total dose is 44 Gy: 2 fractions of 3 Gy per day, 6-hour interval, first and last fraction 4 Gy. Cosmesis is noted in the chart by the medical doctor during follow-up, by the patient (visual analog scale), and by a panel. Finally, full hospital costs are computed. Results: A local relapse-free survival rate of 92% at 5 years was obtained. Four local failures were observed; all four patients were salvaged. The neck was not treated electively; no neck recurrence in follow-up was seen. Excellent cosmetic and functional results were observed. With 10 days admission for full treatment, hospital costs amounted to Euro 5772 ($7044). Conclusion: Excellent tumor control, cosmesis, and function of nasal airway passage can be achieved when HDR-IRT for T1/T2N0 NV cancers is used. For the more advanced cancers (Wang classification: T3 tumor stage), we elect to treat by local excision followed by a reconstructive procedure. The costs, admission to hospital inclusive, for treatment by HDR-IRT amounts to Euro 5772 ($7044 US). This contrasts substantially with the full hospital costs when NV cancers are treated by plastic reconstructive surgery, being on average threefold as expensive.

  16. Early Clinical Outcomes Demonstrate Preserved Cognitive Function in Children With Average-Risk Medulloblastoma When Treated With Hyperfractionated Radiation Therapy

    SciTech Connect

    Gupta, Tejpal; Jalali, Rakesh; Goswami, Savita; Nair, Vimoj; Moiyadi, Aliasgar; Epari, Sridhar; Sarin, Rajiv

    2012-08-01

    Purpose: To report on acute toxicity, longitudinal cognitive function, and early clinical outcomes in children with average-risk medulloblastoma. Methods and Materials: Twenty children {>=}5 years of age classified as having average-risk medulloblastoma were accrued on a prospective protocol of hyperfractionated radiation therapy (HFRT) alone. Radiotherapy was delivered with two daily fractions (1 Gy/fraction, 6 to 8 hours apart, 5 days/week), initially to the neuraxis (36 Gy/36 fractions), followed by conformal tumor bed boost (32 Gy/32 fractions) for a total tumor bed dose of 68 Gy/68 fractions over 6 to 7 weeks. Cognitive function was prospectively assessed longitudinally (pretreatment and at specified posttreatment follow-up visits) with the Wechsler Intelligence Scale for Children to give verbal quotient, performance quotient, and full-scale intelligence quotient (FSIQ). Results: The median age of the study cohort was 8 years (range, 5-14 years), representing a slightly older cohort. Acute hematologic toxicity was mild and self-limiting. Eight (40%) children had subnormal intelligence (FSIQ <85), including 3 (15%) with mild mental retardation (FSIQ 56-70) even before radiotherapy. Cognitive functioning for all tested domains was preserved in children evaluable at 3 months, 1 year, and 2 years after completion of HFRT, with no significant decline over time. Age at diagnosis or baseline FSIQ did not have a significant impact on longitudinal cognitive function. At a median follow-up time of 33 months (range, 16-58 months), 3 patients had died (2 of relapse and 1 of accidental burns), resulting in 3-year relapse-free survival and overall survival of 83.5% and 83.2%, respectively. Conclusion: HFRT without upfront chemotherapy has an acceptable acute toxicity profile, without an unduly increased risk of relapse, with preserved cognitive functioning in children with average-risk medulloblastoma.

  17. Robotic stereotactic body radiation therapy for elderly medically inoperable early-stage non-small cell lung cancer

    PubMed Central

    Karam, Sana D; Horne, Zachary D; Hong, Robert L; Baig, Nimrah; Gagnon, Gregory J; McRae, Don; Duhamel, David; Nasr, Nadim M

    2013-01-01

    Introduction Stereotactic body radiation therapy (SBRT) is being increasingly applied in the treatment of non-small cell lung cancer (NSCLC) because of its high local efficacy. This study aims to examine survival outcomes in elderly patients with inoperable stage I NSCLC treated with SBRT. Methods A total of 31 patients with single lesions treated with fractionated SBRT from 2008 to 2011 were retrospectively analyzed. A median prescribed dose of 48 Gy was delivered to the prescription isodose line, over a median of four treatments. The median biologically effective dose (BED) was 105.6 (range 37.50–180), and the median age was 73 (65–90 years). No patient received concurrent chemotherapy. Results With a median follow up of 13 months (range, 4–40 months), the actuarial median overall survival (OS) and progression-free survival (PFS) were 32 months, and 19 months, respectively. The actuarial median local control (LC) time was not reached. The survival outcomes at median follow up of 13 months were 80%, 68%, and 70% for LC, PFS, and OS, respectively. Univariate analysis revealed a BED of >100 Gy was associated with improved LC rates (P = 0.02), while squamous cell histology predicted for worse LC outcome at median follow up time of 13 months (P = 0.04). Increased tumor volume was a worse prognostic indicator of both LC and OS outcomes (P < 0.05). Finally, female gender was a better prognostic factor for OS than male gender (P = 0.006). There were no prognostic indicators of PFS that reached statistical significance. No acute or subacute high-grade toxicities were documented. Conclusion SBRT is a safe, feasible, and effective treatment option for elderly patients with inoperable early stage NSCLC. BED, histology, and tumor size are predictors of local control, while tumor size and gender predict OS. PMID:28210133

  18. Diffuse optical measurements of head and neck tumor hemodynamics for early prediction of radiation therapy (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Dong, Lixin; Kudrimoti, Mahesh; Irwin, Daniel; Chen, Li; Shang, Yu; Li, Xingzhe; Stevens, Scott D.; Shelton, Brent J.; Yu, Guoqiang

    2016-03-01

    Radiation therapy is a principal modality for head and neck cancers and its efficacy depends on tumor hemodynamics. Our laboratory developed a hybrid diffuse optical instrument allowing for simultaneous measurements of tumor blood flow and oxygenation. In this study, the clinically involved cervical lymph node was monitored by the hybrid instrument once a week over the treatment period of seven weeks. Based on treatment outcomes within one year, patients were classified into a complete response group (CR) and an incomplete response group (IR) with remote metastasis and/or local recurrence. A linear mixed models was used to compare tumor hemodynamic responses to the treatment between the two groups. Interestingly, we found that human papilloma virus (HPV-16) status largely affected tumor hemodynamic responses. For HPV-16 negative tumors, significant differences in blood flow index (BFI, p = 0.007) and reduced scattering coefficient (μs', p = 0.0005) were observed between the two groups; IR tumors exhibited higher μs' values and a continuous increase in BFI over the treatment period. For HPV-16 positive tumors, oxygenated hemoglobin concentration ([HbO2]) and blood oxygen saturation (StO2) were significant different (p = 0.003 and 0.01, respectively); IR group showed lower [HbO2] and StO2. Our results imply HPV-16 negative tumors with higher density of vasculature (μs') and higher blood flow show poor responses to radiotherapy and HPV-16 positive tumors with lower tissue oxygenation level (lower StO2 and [HbO2]) exhibit poor treatment outcomes. Our diffuse optical measurements show the great potential for early prediction of radiotherapy in head and neck cancers.

  19. Radiation-induced early changes in the brain and behavior: serial diffusion tensor imaging and behavioral evaluation after graded doses of radiation.

    PubMed

    Trivedi, Richa; Khan, Ahmad Raza; Rana, Poonam; Haridas, Seenu; Hemanth Kumar, B S; Manda, Kailash; Rathore, Ram K S; Tripathi, Rajendra P; Khushu, Subash

    2012-10-01

    The nuclear arsenal and the use of nuclear technologies have enhanced the likelihood of whole-body/partial-body radiation exposure. The central nervous system is highly susceptible to even low doses of radiation. With the aim of detecting and monitoring the pathologic changes of radiation-induced damage in brain parenchyma, we used serial diffusion tensor magnetic resonance imaging (DTI) with a 7T magnetic resonance unit and neurobehavioral assessments mice irradiated with 3-, 5-, and 8-Gy doses of radiation. Fractional anisotropy (FA) and mean diffusivity (MD) values at each time point (baseline, day 1, day 5, and day 10) were quantified from hippocampus, thalamus, hypothalamus, cudate-putamen, frontal cortex, sensorimotor cortex, corpus callosum, cingulum, and cerebral peduncle. Behavioral tests were performed at baseline, day 5, and day 10. A decrease in FA values with time was observed in all three groups. At day 10, dose-dependent decreases in FA and MD values were observed in all of the regions compared with baseline. Behavioral data obtained in this study correlate with FA values. Radiation-induced affective disorders were not radiation dose dependent, insofar as the anxiety-like symptoms at the lower dose (3 Gy) mimics to the symptoms with the higher dose (8 Gy) level but not with the moderate dose. However, there was a dose-dependent decline in cognitive function as well as FA values. Behavioral data support the DTI indices, so it is suggested that DTI may be a useful tool for noninvasive monitoring of radiation-induced brain injury.

  20. DSB repair model for mammalian cells in early S and G1 phases of the cell cycle: application to damage induced by ionizing radiation of different quality.

    PubMed

    Taleei, Reza; Girard, Peter M; Nikjoo, Hooshang

    2015-02-01

    The purpose of this work is to test the hypothesis that kinetics of double strand breaks (DSB) repair is governed by complexity of DSB. To test the hypothesis we used our recent published mechanistic mathematical model of DSB repair for DSB induced by selected protons, deuterons, and helium ions of different energies representing radiations of different qualities. In light of recent advances in experimental and computational techniques, the most appropriate method to study cellular responses in radiation therapy, and exposures to low doses of ionizing radiations is using mechanistic approaches. To this end, we proposed a 'bottom-up' approach to study cellular response that starts with the DNA damage. Monte Carlo track structure method was employed to simulate initial damage induced in the genomic DNA by direct and indirect effects. Among the different types of DNA damage, DSB are known to be induced in simple and complex forms. The DSB repair model in G1 and early S phases of the cell cycle was employed to calculate the repair kinetics. The model considers the repair of simple and complex DSB, and the DSB produced in the heterochromatin. The inverse sampling method was used to calculate the repair kinetics for each individual DSB. The overall repair kinetics for 500 DSB induced by single tracks of the radiation under test were compared with experimental results. The results show that the model is capable of predicting the repair kinetics for the DSB induced by radiations of different qualities within an accepted range of uncertainty.

  1. Background canceling surface alpha detector

    DOEpatents

    MacArthur, D.W.; Allander, K.S.; Bounds, J.A.

    1996-06-11

    A background canceling long range alpha detector which is capable of providing output proportional to both the alpha radiation emitted from a surface and to radioactive gas emanating from the surface. The detector operates by using an electrical field between first and second signal planes, an enclosure and the surface or substance to be monitored for alpha radiation. The first and second signal planes are maintained at the same voltage with respect to the electrically conductive enclosure, reducing leakage currents. In the presence of alpha radiation and radioactive gas decay, the signal from the first signal plane is proportional to both the surface alpha radiation and to the airborne radioactive gas, while the signal from the second signal plane is proportional only to the airborne radioactive gas. The difference between these two signals is proportional to the surface alpha radiation alone. 5 figs.

  2. Background canceling surface alpha detector

    DOEpatents

    MacArthur, Duncan W.; Allander, Krag S.; Bounds, John A.

    1996-01-01

    A background canceling long range alpha detector which is capable of providing output proportional to both the alpha radiation emitted from a surface and to radioactive gas emanating from the surface. The detector operates by using an electrical field between first and second signal planes, an enclosure and the surface or substance to be monitored for alpha radiation. The first and second signal planes are maintained at the same voltage with respect to the electrically conductive enclosure, reducing leakage currents. In the presence of alpha radiation and radioactive gas decay, the signal from the first signal plane is proportional to both the surface alpha radiation and to the airborne radioactive gas, while the signal from the second signal plane is proportional only to the airborne radioactive gas. The difference between these two signals is proportional to the surface alpha radiation alone.

  3. Adjuvant Hypofractionated Versus Conventional Whole Breast Radiation Therapy for Early-Stage Breast Cancer: Long-Term Hospital-Related Morbidity From Cardiac Causes

    SciTech Connect

    Chan, Elisa K.; Woods, Ryan; McBride, Mary L.; Virani, Sean; Nichol, Alan; Speers, Caroline; Wai, Elaine S.; Tyldesley, Scott

    2014-03-15

    Purpose: The risk of cardiac injury with hypofractionated whole-breast/chest wall radiation therapy (HF-WBI) compared with conventional whole-breast/chest wall radiation therapy (CF-WBI) in women with left-sided breast cancer remains a concern. The purpose of this study was to determine if there is an increase in hospital-related morbidity from cardiac causes with HF-WBI relative to CF-WBI. Methods and Materials: Between 1990 and 1998, 5334 women ≤80 years of age with early-stage breast cancer were treated with postoperative radiation therapy to the breast or chest wall alone. A population-based database recorded baseline patient, tumor, and treatment factors. Hospital administrative records identified baseline cardiac risk factors and other comorbidities. Factors between radiation therapy groups were balanced using a propensity-score model. The first event of a hospital admission for cardiac causes after radiation therapy was determined from hospitalization records. Ten- and 15-year cumulative hospital-related cardiac morbidity after radiation therapy was estimated for left- and right-sided cases using a competing risk approach. Results: The median follow-up was 13.2 years. For left-sided cases, 485 women were treated with CF-WBI, and 2221 women were treated with HF-WBI. Mastectomy was more common in the HF-WBI group, whereas boost was more common in the CF-WBI group. The CF-WBI group had a higher prevalence of diabetes. The 15-year cumulative hospital-related morbidity from cardiac causes (95% confidence interval) was not different between the 2 radiation therapy regimens after propensity-score adjustment: 21% (19-22) with HF-WBI and 21% (17-25) with CF-WBI (P=.93). For right-sided cases, the 15-year cumulative hospital-related morbidity from cardiac causes was also similar between the radiation therapy groups (P=.76). Conclusions: There is no difference in morbidity leading to hospitalization from cardiac causes among women with left-sided early-stage breast

  4. Improved Survival Endpoints With Adjuvant Radiation Treatment in Patients With High-Risk Early-Stage Endometrial Carcinoma

    SciTech Connect

    Elshaikh, Mohamed A.; Vance, Sean; Suri, Jaipreet S.; Mahan, Meredith; Munkarah, Adnan

    2014-02-01

    Purpose/Objective(s): To determine the impact of adjuvant radiation treatment (RT) on recurrence-free survival (RFS), disease-specific survival (DSS), and overall survival (OS) in patients with high-risk 2009 International Federation of Gynecology and Obstetrics stage I-II endometrial carcinoma. Methods and Materials: We identified 382 patients with high-risk EC who underwent hysterectomy. RFS, DSS, and OS were calculated from the date of hysterectomy by use of the Kaplan-Meier method. Cox regression modeling was used to explore the risks associated with various factors on survival endpoints. Results: The median follow-up time for the study cohort was 5.4 years. The median age was 71 years. All patients underwent hysterectomy and salpingo-oophorectomy, 93% had peritoneal cytology, and 85% underwent lymphadenectomy. Patients with endometrioid histology constituted 72% of the study cohort, serous in 16%, clear cell in 7%, and mixed histology in 4%. Twenty-three percent of patients had stage II disease. Adjuvant management included RT alone in 220 patients (57%), chemotherapy alone in 25 patients (7%), and chemoradiation therapy in 27 patients (7%); 110 patients (29%) were treated with close surveillance. The 5-year RFS, DSS, and OS were 76%, 88%, and 73%, respectively. On multivariate analysis, adjuvant RT was a significant predictor of RFS (P<.001) DSS (P<.001), and OS (P=.017). Lymphovascular space involvement was a significant predictor of RFS and DSS (P<.001). High tumor grade was a significant predictor for RFS (P=.038) and DSS (P=.025). Involvement of the lower uterine segment was also a predictor of RFS (P=.049). Age at diagnosis and lymphovascular space involvement were significant predictors of OS: P<.001 and P=.002, respectively. Conclusion: In the treatment of patients with high-risk features, our study suggests that adjuvant RT significantly improves recurrence-free, disease-specific, and overall survival in patients with early-stage endometrial carcinoma

  5. Support Vector Machine-Based Prediction of Local Tumor Control After Stereotactic Body Radiation Therapy for Early-Stage Non-Small Cell Lung Cancer

    SciTech Connect

    Klement, Rainer J.; Allgäuer, Michael; Appold, Steffen; Dieckmann, Karin; Ernst, Iris; Ganswindt, Ute; Holy, Richard; Nestle, Ursula; Nevinny-Stickel, Meinhard; Semrau, Sabine; Sterzing, Florian; Wittig, Andrea; Andratschke, Nicolaus; Guckenberger, Matthias

    2014-03-01

    Background: Several prognostic factors for local tumor control probability (TCP) after stereotactic body radiation therapy (SBRT) for early stage non-small cell lung cancer (NSCLC) have been described, but no attempts have been undertaken to explore whether a nonlinear combination of potential factors might synergistically improve the prediction of local control. Methods and Materials: We investigated a support vector machine (SVM) for predicting TCP in a cohort of 399 patients treated at 13 German and Austrian institutions. Among 7 potential input features for the SVM we selected those most important on the basis of forward feature selection, thereby evaluating classifier performance by using 10-fold cross-validation and computing the area under the ROC curve (AUC). The final SVM classifier was built by repeating the feature selection 10 times with different splitting of the data for cross-validation and finally choosing only those features that were selected at least 5 out of 10 times. It was compared with a multivariate logistic model that was built by forward feature selection. Results: Local failure occurred in 12% of patients. Biologically effective dose (BED) at the isocenter (BED{sub ISO}) was the strongest predictor of TCP in the logistic model and also the most frequently selected input feature for the SVM. A bivariate logistic function of BED{sub ISO} and the pulmonary function indicator forced expiratory volume in 1 second (FEV1) yielded the best description of the data but resulted in a significantly smaller AUC than the final SVM classifier with the input features BED{sub ISO}, age, baseline Karnofsky index, and FEV1 (0.696 ± 0.040 vs 0.789 ± 0.001, P<.03). The final SVM resulted in sensitivity and specificity of 67.0% ± 0.5% and 78.7% ± 0.3%, respectively. Conclusions: These results confirm that machine learning techniques like SVMs can be successfully applied to predict treatment outcome after SBRT. Improvements over traditional TCP

  6. Human radiation studies: Remembering the early years: Oral history of radiation biologist Marvin Goldman, Ph.D., conducted December 22, 1994

    SciTech Connect

    1995-09-01

    This report provides a transcript of an interview of Dr. Marvin Goldman by representatives of DOE`s Office of Human Radiation Experiments. Dr. Goldman was chosen for this interview because of his work on bone-seeking radionuclides. After a brief biographical sketch Dr. Goldman related his experiences concerning his training and work at Rochester University, his work at Brookhaven National Laboratory, his participation in the Beagle Studies at University of California at Davis, his work with the Chernobyl Nuclear Plant Accident, his consultation work with Russian authorities on the health and ecological effects in their history, and finally his opinions and recommendations on human radiation research and the environmental cleanup of DOE sites.

  7. Human radiation studies: Remembering the early years. Oral history of Dr. George Voelz, M.D., November 29, 1994

    SciTech Connect

    1995-05-01

    Dr. George Voelz was interviewed by representatives of the US DOE Office of Human Radiation Experiments (OHRE). This oral history covers Dr. Voelz`s research on Manhattan Engineering District plutonium workers, the acute and long term effects of radiation, his inhalation studies, and his activities at the 1961 INL reactor accident (SL-1 Reactor). After a brief biographical sketch, Dr. Voelz his remembrances on tissue studies of plutonium workers, the plutonium injection studies of 1945-1946, the controlled environmental radioiodine tests of 1963-1968, and tracer studies with human volunteers at Los Alamos. Dr. Voelz states his opinions concerning misconceptions about the Los Alamos Human Radiation Experiments.

  8. Nonthermal cosmic neutrino background

    NASA Astrophysics Data System (ADS)

    Chen, Mu-Chun; Ratz, Michael; Trautner, Andreas

    2015-12-01

    We point out that, for Dirac neutrinos, in addition to the standard thermal cosmic neutrino background (C ν B ), there could also exist a nonthermal neutrino background with comparable number density. As the right-handed components are essentially decoupled from the thermal bath of standard model particles, relic neutrinos with a nonthermal distribution may exist until today. The relic density of the nonthermal (nt) background can be constrained by the usual observational bounds on the effective number of massless degrees of freedom Neff and can be as large as nν nt≲0.5 nγ. In particular, Neff can be larger than 3.046 in the absence of any exotic states. Nonthermal relic neutrinos constitute an irreducible contribution to the detection of the C ν B and, hence, may be discovered by future experiments such as PTOLEMY. We also present a scenario of chaotic inflation in which a nonthermal background can naturally be generated by inflationary preheating. The nonthermal relic neutrinos, thus, may constitute a novel window into the very early Universe.

  9. Neutron-Induced Partial Cross Section Measurements on Cu, Ge and Pb at En = 8 and 12 MeV for Background Radiation in 0νββ Decay Experiments

    NASA Astrophysics Data System (ADS)

    Kwan, E.; Esterline, J. H.; Fallin, B.; Howell, C. R.; Hutcheson, A.; Kidd, M. F.; Tonchev, A.; Tornow, W.; Angell, C.; Karwowski, H.; Kelley, J.; Mei, D.; Hilderbrand, S.; Masters, D. B.; Pedroni, R. S.; Weisel, G. J.

    2008-04-01

    The search for the existence of 0νββ decay plays an important role in the uncovering of physics beyond the standard model. The detection of such decay would confirm that neutrinos are Majorana particles. The large lifetimes (i.e.,T1/2(^76Ge) > 10^25 y) and the corresponding long measuring times require extensive understanding of background radiation induced by neutron interactions with shielding and detector materials. For example, neutron induced γ-ray transitions in Pb and Cu and their escape peaks could interfere with the identification of the 2039 keV signature of 0νββ in the case of ^ 76Ge. Thus, it is necessary to determine the yields from possible background sources. The neutron-induced partial cross sections for γ-ray transitions in Cu, enriched ^76 Ge, and Pb were measured at TUNL using an array of HPGe detectors at En=8 and 12 MeV. The experimental setup and preliminary results will be presented.Supported by DOE Grants DE-FG02-97ER41033 & DE- FG02-97ER41042.