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Sample records for background photoneutrons aspekty

  1. On the threshold sensitivity of low background photoneutron systems

    International Nuclear Information System (INIS)

    Kazakevich, G.M.; Ponomarchuk, V.A.; Filippov, E.M.

    1973-01-01

    A mathematical substantiation is given of determining the sensitivity threshold for a number of photoneutron devices used in practice (Berill-2, Berill-4 etc.). It is shown that, considering various effects and a real time of measurements, the sensitivity threshold of the photoneutron devices waries within the range of 1.3x10 -3 % (Berill-3) to 2.2x10 -5 %

  2. Low level photoneutron detection equipment

    International Nuclear Information System (INIS)

    Ji Changsong; Zhang Yuqin; Li Yuansui

    1991-01-01

    A low level photoneutron detection equipment has been developed. The photoneutrons produced by interaction of 226 Ra gamma quanta and deutron (D) target are detected with n-n discrimination detector made up of 3 He proportional counter array. The D-content information in the target can be obtained from the measured photoneutron counts. The equipment developed is mainly used for nondestructive D-content measurement of D-devices

  3. Atlas of photoneutron cross sections obtained with monoenergetic photons

    International Nuclear Information System (INIS)

    Dietrich, S.S.; Berman, B.L.

    1988-01-01

    Photoneutron cross-section and integrated cross-section data obtained with monoenergetic photons are presented in a uniform format. All of the measured partial photoneutron cross sections, the total photoneutron cross section, and the photoneutron yield cross section are plotted as functions of the incident photon energy, as are the integrated photoneutron cross sections and their first and second moments. The values of the integrated cross sections and the moments of the integrated total cross section up to the highest photon energy for which they were measured are tabulated, as are the parameters of Lorentz curves fitted to the total photoneutron cross-section data for medium and heavy nuclei (A>50). This compilation is current as of June 1987. copyright 1988 Academic Press, Inc

  4. A photoneutron production option for MCNP4A

    International Nuclear Information System (INIS)

    Gallmeier, F.X.

    1996-01-01

    A photoneutron production option was implemented in the MCNP4A code, mainly to supply a tool for reactor shielding calculations in beryllium and heavy water environments of complicated three dimensional geometries. Subroutines were developed to calculate the probability of the photoneutron production at the photon collision sites and the energy and flight direction of the created photoneutrons with the help of user supplied data. These subroutines are accessed through subroutine colidp which processes the photon collisions

  5. Polarization of photoneutrons from the threshold region of 208Pb

    International Nuclear Information System (INIS)

    Holt, R.J.; Jackson, H.E.

    1975-01-01

    In order to determine the parities of several resonances in 208 Pb, the polarization of photoneutrons from the 208 Pb(γ,n(pol)) 207 Pb reaction was measured. This represents the first measurement of the polarization of photoneutrons from resonances near threshold. The observations are tabulated. (SDF)

  6. Photoneutron Reaction Data for Nuclear Physics and Astrophysics

    Directory of Open Access Journals (Sweden)

    Utsunomiya Hiroaki

    2018-01-01

    Full Text Available We discuss the role of photoneutron reaction data in nuclear physics and astrophysics in conjunction with the Coordinated Research Project of the International Atomic Energy Agency with the code F41032 (IAEA-CRP F41032.

  7. Photoneutron Reaction Data for Nuclear Physics and Astrophysics

    Science.gov (United States)

    Utsunomiya, Hiroaki; Renstrøm, Therese; Tveten, Gry Merete; Gheorghe, Ioana; Filipescu, Dan Mihai; Belyshev, Sergey; Stopani, Konstantin; Wang, Hongwei; Fan, Gongtao; Lui, Yiu-Wing; Symochko, Dmytro; Goriely, Stephane; Larsen, Ann-Cecilie; Siem, Sunniva; Varlamov, Vladimir; Ishkhanov, Boris; Glodariu, Tudor; Krzysiek, Mateusz; Takenaka, Daiki; Ari-izumi, Takashi; Amano, Sho; Miyamoto, Shuji

    2018-05-01

    We discuss the role of photoneutron reaction data in nuclear physics and astrophysics in conjunction with the Coordinated Research Project of the International Atomic Energy Agency with the code F41032 (IAEA-CRP F41032).

  8. Personnel hazards from medical electron accelerator photoneutrons

    International Nuclear Information System (INIS)

    Mcall, R.C.; Jenkins, T.M.; Shore, R.A.; LaRiviere, P.D.

    1980-01-01

    Medical electron accelerators operated in the photon mode produce significant amounts of photoneutrons at energies above 15 MeV. There can be definite radiation problems at doors of treatment rooms where operating consoles are often located. These problems are due in large part to inadequate maze design by physicists unaccustomed to shielding against neutrons. The radiation field at the door is an unusual combination of low energy neutrons, thermal neutrons and capture γ-rays from the concrete walls of the maze and the door itself. While this radiation field is dependent upon the actual construction details, these three components each contribute roughly one-third of the total dose equivalent. Reducing these high radiation levels presents a formidable problem. The neutrons can be absorbed by hydrogenous material which can be attached to the door, but the neutron capture γ-rays would require massive amounts of lead for the required attenuation. Both measurements and Monte Carlo calculations are presented to illustrate the problem. Some possible shielding solutions are presented for pre-existing treatment rooms, as well as design recommendations for new rooms. (H.K.)

  9. Monitoring of MNSR operation by measuring subcritical photoneutron flux

    International Nuclear Information System (INIS)

    Haddad, Kh.; Alsomel, N.

    2011-01-01

    Passive nondestructive assay methods are used to monitor the reactor's operation. It is required for nuclear regulatory, calculation validation and safeguards purposes. So, it plays a vital role in the safety and security of the nuclear plants. The possibility of MNSR operation monitoring by measuring the subcritical state photoneutron flux were investigated in this work. The photoneutron flux is induced by the fuels hard gamma radiation in the beryllium reflector. Theoretical formulation and experimental tests were performed. The results show that within a specified cooling time range, the photoneutron flux is induced by a single dominant hard gamma emitter such as 117 Cd (activation product) and 140 Ba ( 140 La fission product). This phenomenon was utilized to monitor the cooling time and the operation neutron flux during the last campaign. Thus a passive nondestructive assay method is proposed with regard to the reactor operation's monitoring.

  10. The simulation of resonance photoneutron produced by dragon-I

    International Nuclear Information System (INIS)

    Xiang Yanjun; Ma Jingfang

    2010-01-01

    The temperature measurement using neutron resonance spectroscopy has many advantages such as non-immerging, inside measurement and local temperature distribution measurement, but the deficiency of high intensity pulsed neutron source limits it's application.In order to study the feasibility of Dragon-I as the pulsed neutron source of temperature measurement, the photoneutron characteristic had been simulated by MCNP5, the photoneutron yield is 1.34 x 10 11 per electron pulse, pulse width is 90ns. the yield is as high as 7.47 x 10 12 per electron pulse when 8cm thick U target had been used, which is only one magnitude lower than the yield of spallation source. the moderation of photoneutron had been simulated using some moderator, the results displayed Dragon-I can be a high intensity,narrow pulse neutron source, it's necessary to study further about it's application to temperature measurement using neutron resonance spectroscopy. (authors)

  11. NAA using the photoneutrons of a Linac as a neutron source

    International Nuclear Information System (INIS)

    Rivera P, E.; De Leon M, H. A.; Hernandez D, V. M.; Vega C, H. R.; Soto B, T.; Gallego, E.; Lorente, A.

    2012-10-01

    Linear accelerators working above 8 MV produce photoneutrons that represent a radiological risk in the patient and hospital staff. In this work a moderator has been designed in the aim to use the photoneutron field to perform neutron activation analysis (NAA) of small samples. The moderator has been designed using Monte Carlo methods, here the photoneutron spectrum is modified by the moderator having the maximum thermal neutron flux in the moderator cavity where the sample to be analyzed is located. (Author)

  12. Delayed photoneutrons of the of the Dalat Nuclear Research Reactor

    International Nuclear Information System (INIS)

    Ngo Quang Huy; Ha Van Thong; Vu Hai Long; Ngo Phu Khang; Nguyen Nhi Dien; Pham Van Lam; Huynh Dong Phuong; Luong Ba Vien; Le Vinh Vinh

    1994-01-01

    Time spectrum of delayed neutrons of the Dalat nuclear research reactor is measured and analyzed. It corresponds to a shut-down neutron fluxes of about 10 5 /10 8 n/cm 2 /sec after 100 hours continuous reactor operation at steady power level of 500 kW. Data processing of experimental time neutron spectrum gives 16 exponents, of which 10, resulting from photoneutrons due to (γ,n) reactions on beryllium used inside the reactor core, are obtained by using successive exponential stripping fitting method. For the Dalat reactor, the effective delayed photoneutron fraction relative to the total effective delayed neutron fraction is β B e eff =0.49%β eff for a beryllium weight relative to U 235 fuel of m B e/m U = 8.5. This result is acceptable in comparison to those obtained for other Be-U 235 media. (author). 5 refs., 2 figs., 4 tabs

  13. Photons and photoneutrons spectra of a Linac of 15 MV

    International Nuclear Information System (INIS)

    Benites R, J. L.; Carrillo C, A.; Vega C, H. R.; Velazquez F, J. B.

    2011-10-01

    Using the Monte Carlo code MCNP-5, the photons and photoneutrons spectra generated in the head stock of the lineal accelerator (Linac) Varian of 15 MV of the Cancerology State of Nayarit were determined. For the calculations a heterogeneous head stock was modeled, more compatible with the work conditions. In the center of the head stock a tungsten target was located on a copper support, followed by the flattened filter. The photons and photoneutrons spectra were obtained accelerating electrons and making them collide against the target to produce photons by Bremsstrahlung, these photons were transported inside the head stock and the photons and photoneutrons spectra were calculated in a punctual detector located under the flattened filter and in the isocenter. The spectra were evaluated in punctual detectors that were located in the plane from the isocenter to the long of the X and Y axes each 20 cm, in an equidistant way, up to 2 m, so much in the longitudinal and transversal axes. In the calculations were used histories 5E(6) with the purpose of obtaining smaller uncertainties to 1%. It was found that the photons spectrum in the punctual detector inside the head stock presents a pick of 1.25 MeV in the energy interval of 0.5 and 1.5 MeV, later suffers a filtration and diminishes in asymptote form. This spectrum modifies when the beam reaches the isocenter, diminishing the low energy photons. Inside the head stock the photoneutrons spectrum shows a structure with two picks, one before 1 MeV and other after 1 MeV; this is for effect of the collimators geometry and the distance. Finally an increment of the total neutrons flow to 60 cm of distance of the isocenter on the Y axis was observed, due to the design geometry of the modeling heterogeneous head stock. (Author)

  14. Optimization studies of photo-neutron production in high-Z metallic ...

    Indian Academy of Sciences (India)

    Monte Carlo calculations have been performed using MCNP code to study the optimization of photo-neutron yield for different electron beam energies impinging on Pb, W and Ta cylindrical targets of varying thickness. It is noticed that photo-neutron yield can be increased for electron beam energies ≥ 100 MeV for ...

  15. Photoneutron spectrum measured with Bonner Spheres in Planetary method mode

    Energy Technology Data Exchange (ETDEWEB)

    Benites R, J. [Centro Estatal de Cancerologia de Nayarit, Servicio de Seguridad Radiologica, Calz. de la Cruz 118 Sur, 63000 Tepic, Nayarit (Mexico); Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Apdo. Postal 336, 98000 Zacatecas (Mexico); Velazquez F, J., E-mail: jlbenitesr@prodigy.net.mx [Universidad Autonoma de Nayarit, Posgrado en Ciencias Biologico Agropecuarias, Carretera Tepic-Compostela Km 9, 63780 Jalisco-Nayarit (Mexico)

    2012-10-15

    We measured the spectrum of photoneutrons at 100 cm isocenter linear accelerator (Linac) Varian ix operating at 15 MV Bremsstrahlung mode. In this process was used a radiation field of 20 x 20 cm{sup 2} at a depth of 5 cm in a solid water phantom with dimensions of 30 x 30 x 15 cm{sup 3}. The measurement was performed with a system using it Bonner Spheres spectrometric method Planetary mode. As neutron detector of the spectrometer is used thermoluminescent dosimeters pairs of type 600 and 700. (Author)

  16. Photoneutron spectrum measured with Bonner Spheres in Planetary method mode

    International Nuclear Information System (INIS)

    Benites R, J.; Vega C, H. R.; Velazquez F, J.

    2012-10-01

    We measured the spectrum of photoneutrons at 100 cm isocenter linear accelerator (Linac) Varian ix operating at 15 MV Bremsstrahlung mode. In this process was used a radiation field of 20 x 20 cm 2 at a depth of 5 cm in a solid water phantom with dimensions of 30 x 30 x 15 cm 3 . The measurement was performed with a system using it Bonner Spheres spectrometric method Planetary mode. As neutron detector of the spectrometer is used thermoluminescent dosimeters pairs of type 600 and 700. (Author)

  17. Sensitization of the analytical methods for photoneutron calculations to the wall concrete composition in radiation therapy

    International Nuclear Information System (INIS)

    Ghiasi, Hosein; Mesbahi, Asghar

    2012-01-01

    The effect of wall material on photoneutron production in radiation therapy rooms was studied using Monte Carlo (MC) simulations. An analytical formula was proposed to take into account the concrete composition in photoneutron dose calculations. Using the MCNPX MC code, the 18 MV photon beam of the Varian Clinac 2100 and a typical treatment room with concrete compositions according to report No. 144 of National Council of Radiation Protection (NCRP) were simulated. Number of room produced photoneutrons per Gray of X-ray at the isocenter was determined for different types of concrete and named as “Q W ”. This new factor was inserted in the used formula for photoneutron fluence calculations at the inner entrance of maze. The photoneutron fluence was calculated using new proposed formula at the inner entrance of maze for all studied concretes. The difference between conventional and proposed equations varied from 11% to 46% for studied concretes. It was found that room produced photoneutrons could be significant for high density concretes. Additionally, applying the new proposed formula can consider the effect of wall material composition on the photoneutron production in high energy radiation therapy rooms. Further studies to confirm the accuracy of newly developed method is recommended.

  18. Delayed photoneutrons of the of the Dalat Nuclear Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Huy, Ngo Quang [Centre for Nuclear Technique Application, Ho Chi Minh City (Viet Nam); Thong, Ha Van; Long, Vu Hai; Khang, Ngo Phu; Dien, Nguyen Nhi; Lam, Pham Van; Phuong, Huynh Dong; Vien, Luong Ba; Vinh, Le Vinh [Nuclear Research Inst., Da Lat (Viet Nam)

    1994-10-01

    Time spectrum of delayed neutrons of the Dalat nuclear research reactor is measured and analyzed. It corresponds to a shut-down neutron fluxes of about 10{sup 5}/10{sup 8} n/cm{sup 2}/sec after 100 hours continuous reactor operation at steady power level of 500 kW. Data processing of experimental time neutron spectrum gives 16 exponents, of which 10, resulting from photoneutrons due to ({gamma},n) reactions on beryllium used inside the reactor core, are obtained by using successive exponential stripping fitting method. For the Dalat reactor, the effective delayed photoneutron fraction relative to the total effective delayed neutron fraction is {beta}{sup B}e{sub eff}=0.49%{beta}{sub eff} for a beryllium weight relative to U{sup 235} fuel of m{sub B}e/m{sub U} = 8.5. This result is acceptable in comparison to those obtained for other Be-U{sup 235} media. (author). 5 refs., 2 figs., 4 tabs.

  19. Optimization aspects of the new nELBE photo-neutron source

    Directory of Open Access Journals (Sweden)

    Schwengner R.

    2010-10-01

    Full Text Available The nELBE beamline at Forschungszentrum Dresden-Rossendorf (FZD provides intense neutron beams by stopping primary electrons in a liquid lead target, where neutrons are produced by bremsstrahlung photons via (γ,n reactions. With the aim to increase the neutron yield through the enhancement of the electron beam energy (from the current 40 MeV limit up to 50 MeV, as well as to minimize several sources of background that are presently affecting the measurements, a new neutron beam-line and a new, larger neutron experimental room have been designed. The optimization of the neutron/photon ratio, the minimization of the backscattered radiation from the walls and the possibility to have better experimental conditions are the main advantages of the new design. To optimize the beamline, extensive simulations with the particle interaction and transport code FLUKA have been performed. Starting from the primary electron beam, both the photon and neutron radiation fields have been fully characterized. To have a cross-check of the results, the calculated values of the neutron yields at different energies of the primary beam have been compared both with an independent simulation with the MCNP code and with analytical calculations, obtaining a very satisfactory agreement at the level of few percent. The evaluated radiation fields have been used to optimize the direction of the new neutron beamline, in order to minimize the photon flash contribution. A general overview of the new photo-neutron source, together with all the steps of the optimization study, is here presented and discussed.

  20. Photoneutrons from medical linear accelerators--radiobiological measurements and risk estimates

    International Nuclear Information System (INIS)

    Hall, Eric J.; Martin, Stewart G.; Amols, Howard; Hei, Tom K.

    1995-01-01

    Purpose: To assess the oncogenic potential of the photoneutrons produced by high energy medical linear accelerators. Methods and Materials: An established line of cells of rodent origin (C 3 H 10T1/2) was used to assess the oncogenic potential of the radiation dose received in the breast of an anthropomorphic 'randoman' phanton, while the cervix received a dose of 70 Gy. Experiments were performed at 6 MV, below the threshold for the production of photoneutrons, and at 20 MV where the dose includes about 0.01 Gy of photoneutrons as well as scattered x-rays. Results: A significantly higher transformation incidence was observed for the 20-MV machine, consistent with the measured neutron dose of about 0.01 Gy and a quality factor of 20. Conclusion: An estimate can be made of the additional deaths from second malignancies that might result from the photoneutrons generated by higher energy linear accelerators (Linacs), which must be offset against the possible improvements in survival that might result from the higher tumor doses made possible by the increased percentage depth doses

  1. Spectra of photoneutrons produced by high energy X-ray radiotherapy linacs

    Czech Academy of Sciences Publication Activity Database

    Králík, M.; Turek, Karel

    2008-01-01

    Roč. 132, č. 1 (2008), s. 13-17 ISSN 0144-8420 Institutional research plan: CEZ:AV0Z10480505 Keywords : photoneutrons * Bonner spectrometer * track detectors Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.951, year: 2008

  2. The quasi-monochromatic photon beam used in photoneutron experiments from 20-120 MeV at the 600 MeV Saclay Linac

    International Nuclear Information System (INIS)

    Veyssiere, A.; Beil, H.; Bergere, R.; Carlos, P.; Fagot, J.; Lepretre, A.; Ahrens, J.

    1979-01-01

    A beam of 20-130 MeV positrons, with average intensities between 10 nA and 50 nA, is used at the 600 MeV Saclay Linac to create a quasi-monochromatic photon beam with a continuously variable energy. This beam was used to measure photoneutron cross sections and the corresponding photonuclear facility is first described. The computer-controlled methods, implemented to measure the energy spectrum and the emittance of the positron beam are described. The quasi-monochromatic photon lines are produced by the annihilation in flight of monoenergetic positrons in two annihilation radiators with different Z successively. The photon beam emission angle theta is shown to be the most critical parameter in the search for an optimum overall signal to background ratio for a specific photoneutron experiment. The choice of an angle theta approximately 4 0 is explained for absolute measurements of sigma(γ, xn) cross-sections, for which the used average intensities of monochromatic photons were thus purposely reduced to approximately 5 X 10 3 s -1 , with an energy resolution approximately 12%. (Auth.)

  3. Setup and taking into operation of a photoneutron source; Aufbau und Inbetriebnahme einer Photoneutronenquelle

    Energy Technology Data Exchange (ETDEWEB)

    Greschner, Martin

    2013-07-01

    The Institute for Nuclear and Particle Physics at the Technische Universitaet Dresden (TUD) has build a neutron physics laboratory at Forschungszentrum Dresden-Rossendorf (FZD) to investigate nuclear processes in materials. The experiments are focused on materials relevant to nuclear fusion. The laboratory is equipped with three intensive neutron sources. The first is a 14 MeV monochromatic neutron source based on the DT reaction (owned by TUD); the other two are continuous and pulsed white photoneutron sources based on (γ,xn) reactions. One pulsed photoneutron source is realized by FZD in cooperation with the TUD. The continuous photoneutron source utilises a tungsten radiator (Tungsten Photoneutron Source) to produce neutrons with a wide energy spectra. The TPNS uses the ELBE-accelerator as a source of electrons for neutron production. This process involves an intermediate step, where slowed down electrons produce bremsstrahlung (γ-rays) absorbed by tungsten nuclei. Consecutively, the excited nuclei emit neutrons. The neutron flux of the photoneutron source is five orders of magnitude higher than the flux of the DT neutron sources with appropriate moderation. The neutron spectrum of TPNS can be modified by moderators, in such a way that the spectrum is comparable to that in the first wall of a Tokamak-Reactor. That allows investigations with the typical neutron spectrum of the fusion reactor. The technical solution, initial operation and the first experiment are described in this work. The neutron source is, in particular, dedicated to quantitative investigations in fusion neutronics. A fusion reactor produces radioactive isotopes as a nuclear waste. The main activity is accumulated in the structural materials. Carefully selected structural materials can significantly minimize the activity and thereby the amount of nuclear waste. The purpose of this project is to find constructional materials with half-lives shorter than several years, which can be recycled

  4. Detection of actinides with an electron accelerator by active photoneutron interrogation measurements

    International Nuclear Information System (INIS)

    Sari, A.; Carrel, F.; Gmar, M.; Laine, F.; Normand, S.; Lyoussi, A.

    2012-01-01

    The solution for management of a nuclear waste package is chosen according to its radiological characteristics. One of the most important of these features is the α-activity which is due to actinides ( 235 U, 238 U, 239 Pu, etc.) If non-destructive passive methods are not sufficient to quantify the latter, non-destructive active methods based on the fission process represent a solution of interest. First, these methods consist in irradiating a package in order to induce fission reactions on the actinides, and then, to detect the prompt and delayed particles which are emitted following these reactions. Our aim is to conduct neutron interrogation measurements on nuclear waste packages using an electron accelerator as a photoneutron generator. One of the main interests of this approach is that the intensity of the neutron flux can be one or two orders of magnitude higher than the one delivered by a deuterium-tritium generator. With the objective of improving nuclear waste characterization, the development of this method could enable the integration of three complementary techniques on a single measurement cell (active neutron interrogation, active photon interrogation, and high-energy imaging). In this paper, simulation and experimental results are presented. A simulation study using MCNPX has been conducted in order to determine the characteristics of the photoneutron flux emitted by the electron accelerator of the SAPHIR facility owned by CEA LIST. Energy spectra, angular distribution and intensity of the photoneutron flux have been obtained. A photoneutron interrogation measurement cell based on this accelerator has been built and assessed by carrying out measurements on uranium samples. Delayed gamma-ray spectra have been acquired and enabled to confirm the experimental feasibility of our method. (authors)

  5. An accelerator-based epithermal photoneutron source for boron neutron capture therapy

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, Hannah E. [Georgia Inst. of Technology, Atlanta, GA (United States)

    1996-04-01

    Boron neutron capture therapy is an experimental binary cancer radiotherapy modality in which a boronated pharmaceutical that preferentially accumulates in malignant tissue is first administered, followed by exposing the tissue in the treatment volume to a thermal neutron field. Current usable beams are reactor-based but a viable alternative is the production of an epithermal neutron beam from an accelerator. Current literature cites various proposed accelerator-based designs, most of which are based on proton beams with beryllium or lithium targets. This dissertation examines the efficacy of a novel approach to BNCT treatments that incorporates an electron linear accelerator in the production of a photoneutron source. This source may help to resolve some of the present concerns associated with accelerator sources, including that of target cooling. The photoneutron production process is discussed as a possible alternate source of neutrons for eventual BNCT treatments for cancer. A conceptual design to produce epithermal photoneutrons by high photons (due to bremsstrahlung) impinging on deuterium targets is presented along with computational and experimental neutron production data. A clinically acceptable filtered epithermal neutron flux on the order of 107 neutrons per second per milliampere of electron current is shown to be obtainable. Additionally, the neutron beam is modified and characterized for BNCT applications by employing two unique moderating materials (an Al/AlF3 composite and a stacked Al/Teflon design) at various incident electron energies.

  6. An accelerator-based epithermal photoneutron source for boron neutron capture therapy

    International Nuclear Information System (INIS)

    Mitchell, H.E.

    1996-04-01

    Boron neutron capture therapy is an experimental binary cancer radiotherapy modality in which a boronated pharmaceutical that preferentially accumulates in malignant tissue is first administered, followed by exposing the tissue in the treatment volume to a thermal neutron field. Current usable beams are reactor-based but a viable alternative is the production of an epithermal neutron beam from an accelerator. Current literature cites various proposed accelerator-based designs, most of which are based on proton beams with beryllium or lithium targets. This dissertation examines the efficacy of a novel approach to BNCT treatments that incorporates an electron linear accelerator in the production of a photoneutron source. This source may help to resolve some of the present concerns associated with accelerator sources, including that of target cooling. The photoneutron production process is discussed as a possible alternate source of neutrons for eventual BNCT treatments for cancer. A conceptual design to produce epithermal photoneutrons by high photons (due to bremsstrahlung) impinging on deuterium targets is presented along with computational and experimental neutron production data. A clinically acceptable filtered epithermal neutron flux on the order of 10 7 neutrons per second per milliampere of electron current is shown to be obtainable. Additionally, the neutron beam is modified and characterized for BNCT applications by employing two unique moderating materials (an Al/AlF 3 composite and a stacked Al/Teflon design) at various incident electron energies

  7. Calculations of the giant-dipole-resonance photoneutrons using a coupled EGS4-morse code

    International Nuclear Information System (INIS)

    Liu, J.C.; Nelson, W.R.; Kase, K.R.; Mao, X.S.

    1995-10-01

    The production and transport of the photoneutrons from the giant-dipoleresonance reaction have been implemented in a coupled EGS4-MORSE code. The total neutron yield (including both the direct neutron and evaporation neutron components) is calculated by folding the photoneutron yield cross sections with the photon track length distribution in the target. Empirical algorithms based on the measurements have been developed to estimate the fraction and energy of the direct neutron component for each photon. The statistical theory in the EVAP4 code, incorporated as a MORSE subroutine, is used to determine the energies of the evaporation neutrons. These represent major improvements over other calculations that assumed no direct neutrons, a constant fraction of direct neutrons, monoenergetic direct neutron, or a constant nuclear temperature for the evaporation neutrons. It was also assumed that the slow neutrons ( 2 θ, which have a peak emission at 900. Comparisons between the calculated and the measured photoneutron results (spectra of the direct, evaporation and total neutrons; nuclear temperatures; direct neutron fractions) for materials of lead, tungsten, tantalum and copper have been made. The results show that the empirical algorithms, albeit simple, can produce reasonable results over the interested photon energy range

  8. The photoneutron yield predictions by PICA and comparison with the measurements

    International Nuclear Information System (INIS)

    Job, P.K.; Gabriel, T.A.

    1995-01-01

    The photoneutron yields at higher photon energies have become very important since the advent of high energy electron accelerators. Bremsstrahlung is produced when the particle beam interacts with the storage-ring components or residual-gas molecules in the storage-ring vacuum. Bremsstrahlung thus produced interacts with the high-Z materials in the beamline like the beam dumps and collimators to produce photoneutrons. There are three modes of neutron production by bremsstrahlung. At low energies (≥525 MeV), photons are absorbed by the dipole interaction and the compound nucleus thus formed decays emitting protons and neutrons and other heavier particles. At higher energies (≥25 MeV), photon interacts with the nucleus through absorption on a quasi-deuteron, which subsequently decays producing a neutron and proton pair which can interact with the rest of the nucleus. At still higher energies the photopion production becomes possible and competes with the quasi-deuteron process. In this paper we have calculated the photoneutron yield from a thick copper target using the photonuclear interaction code PICA. Using this as the neutron source, we have calculated the dose rates through heavy concrete and compared it with the measurements made at the Advanced Photon Source at Argonne National Lab

  9. Tutoring nauczycielski – tutoring rówieśniczy: aspekty etyczne

    OpenAIRE

    Brzezińska, Anna Izabela; Appelt, Karolina

    2013-01-01

    W artykule autorki wskazują na różnorodne aspekty etyczne stosowania w edukacji metody tutoringu zarówno nauczycielskiego, jak i rówieśniczego. Podstawowym wg nich warunkiem etycznej, a zarazem efektywnej relacji tutorskiej jest – zgodnie z koncepcją samostanowienia Ryana i Deci’ego – zaspokojenie podstawowych, uniwersalnych potrzeb wszystkich partnerów interakcji: potrzeby więzi i bezpieczeństwa, potrzeby autonomii i potrzeby kompetencji. Uświadomienie sobie i uwzględnienie w działaniu tych ...

  10. Právní aspekty jeruzalémského procesu s Adolfem Eichmannem

    OpenAIRE

    Kohout, David

    2009-01-01

    -89- 6 English Résumé, Key Words Právní aspekty jeruzalémského procesu s Adolfem Eichmannem Legal Aspects of the Jerusalem Trial of Adolf Eichmann Résumé In this diploma thesis I tried to provide a more or less complete overview of legal aspects of the trial of Adolf Eichmann and to point out some of its extra-legal consequences too. This trial took place in Jerusalem and together with the pre-trial proceedings it spanned more than two years. On the course of those two years (and predominan...

  11. Identification of High-Z Materials With Photoneutrons Driven by a Low-Energy Electron Linear Accelerator

    Science.gov (United States)

    Yang, Yigang; Zhang, Zhi; Chen, Huaibi; Li, Yulan; Li, Yuanjing

    2017-07-01

    Contraband-detection systems can use X-rays and photoneutrons delivered from the same 7-MeV electron linear accelerator (e-LINAC) to stimulate and extract information from inspected materials. The X-ray attenuation information is used to measure the mass thickness, which is combined with the photoneutron attenuation information to categorize inspected materials as common organic materials, metals, and heavy metals. Once a heavy metal is found, the beta-delayed neutrons stimulated by the (γ,fission) reaction are measured by a polyethylene-moderated 3He counter to clarify if the material is fissile. The presence of neutron events 2000 μs after the X-ray pulse confirms the existence of the fissile material. The isotopes in the material are then identified using the time-of-flight method to analyze the resonant attenuation of the fissile material to the 10-1-102 eV photoneutrons emitted from and thermalized by the D2O photonto-neutron convertor, which converts X-rays to photoneutrons. Eight high-Z simulants are tested to confirm the feasibility of identifying the isotopes from the photoneutron resonance. The underlying principles and experimental results are discussed.

  12. New approach to analyzing and evaluating cross sections for partial photoneutron reactions

    International Nuclear Information System (INIS)

    Varlamov, V. V.; Ishkhanov, B. S.; Orlin, V. N.

    2012-01-01

    The presence of substantial systematic discrepancies between the results of different experiments devoted to determining cross sections for partial photoneutron reactions—first of all, (γ, n), (γ, 2n), and (γ, 3n) reactions—is a strong motivation for studying the reliability and authenticity of these data and for developing methods for taking into account and removing the discrepancies in question. In order to solve the first problem, we introduce objective absolute criteria involving transitional photoneutron-multiplicity functions F 1 , F 2 , F 3 , …; by definition, their values cannot exceed 1.0, 0.5, 0.33, …, respectively. With the aim of solving the second problem, we propose a new experimental-theoretical approach. In this approach, reaction cross sections are evaluated by simultaneously employing experimental data on the cross section for the total photoneutron yield, σ expt (γ, xn) = σ expt (γ, n) + 2σ expt (γ, 2n) + 3σ expt (γ, 3n) + …, which are free from drawbacks plaguing experimental methods for sorting neutrons in multiplicity, and the results obtained by calculating the functions F theor 1 , F theor 2 , F theor 3 , … on the basis of the modern model of photonuclear reactions. The reliability and authenticity of data on the cross sections for (γ, n), (γ, 2n), and (γ, 3n) partial reactions—σ eval (γ, in) = F i theor σ expt (γ, xn)—were evaluated for the 90 Zr, 115 In, 112,114,116,117,118,119,120,122,124 Sn, 159 Tb, and 197 Au nuclei.

  13. Photoneutron source based on a compact 10 MeV betatron

    International Nuclear Information System (INIS)

    Chakhlov, V.L.; Bell, Z.W.; Golovkov, V.M.; Shtein, M.M.

    1999-01-01

    Accelerator-based photoneutron sources have enjoyed wide use and offer the advantages of long term stability, ease of control and absence of radioactive materials. We report here measurements of the yield of photoneutrons from a neutron generator using a compact betatron. Electrons were accelerated to energies up to 10 MeV and produced a bremsstrahlung beam with a dose rate of 0.16 Gy/min (at 10 MeV, 1 m from the bremsstrahlung target) to irradiate LiD, Be, depleted U, and Pb neutron-producing targets. The angular distributions of photoneutrons produced by bremsstrahlung beams were measured with a 'long' counter and integrated to determine neutron yield. In addition, neutron time of flight spectra were recorded from all targets using a 15.5 m flight path perpendicular to the photon beam. The maximum observed yields were 4.6x10 7 n/s obtained with 1 kg of LiD, 5.7x10 7 n/s from a 3.3 kg Be block, 6.2x10 6 n/s from 1.5 kg of depleted U, and 7.0x10 6 n/s from 10.7 kg of Pb. Optimization of target dimensions, shape, and positioning is expected to increase the yield from the LiD target by a factor of 35, while optimization of the other targets is expected to yield at most a factor of 10. With the increased yield and a deuteride target, this compact betatron-based system could find application in the interrogation of waste containers for fissile material

  14. Photoneutron source based on a compact 10 MeV betatron

    International Nuclear Information System (INIS)

    Bell, Z.W.; Chaklov, V.L.; Golovkov, V.M.

    1998-01-01

    Accelerator-based photoneutron sources have enjoyed wide use and offer the advantages of long term stability, ease of control and absence of radioactive materials. The authors report here measurements of the yield of photoneutrons from a neutron generator using a compact betatron (466 kg total weight, 900 by 560 by 350 mm betatron dimensions) at the Institute of Introscopy of the Tomsk Polytechnic University. Electrons were accelerated to energies up to 10 MeV and produced a bremsstrahlung beam with a dose rate of 0.16 Gy/min (at 10 MeV, 1 meter from the bremsstrahlung target) to irradiate LiD, Be, depleted U, and Pb neutron-producing targets. The angular distributions of photoneutrons produced by bremsstrahlung beams were measured with a long counter and integrated to determine neutron yield. In addition, neutron time of flight spectra were recorded from all targets using a 15 meter flight path perpendicular to the photon beam. The maximum observed yields were 5.2 x 10 4 n/rad/gram target obtained with LiD, 1.7 x 10 4 n/rad/gram from Be, 3.3 x 10 3 n/rad/gram from U, and 7.5 x 10 2 n/rad/gram from Pb. Optimization of target dimensions, shape, and positioning is expected to increase the yield from the LiD target by a factor of 35. With the increased yield, this compact betatron-based system could find application in the interrogation of waste containers for fissile material

  15. Neutron total cross section measurements of gold and tantalum at the nELBE photoneutron source

    CERN Document Server

    Hannaske, Roland; Beyer, Roland; Junghans, Arnd; Bemmerer, Daniel; Birgersson, Evert; Ferrari, Anna; Grosse, Eckart; Kempe, Mathias; Kögler, Toni; Marta, Michele; Massarczyk, Ralph; Matic, Andrija; Schramm, Georg; Schwengner, Ronald; Wagner, Andreas

    2014-01-01

    Neutron total cross sections of 197 Au and nat Ta have been measured at the nELBE photoneutron source in the energy range from 0.1 - 10 MeV with a statistical uncertainty of up to 2 % and a total systematic uncertainty of 1 %. This facility is optimized for the fast neutron energy range and combines an excellent t ime structure of the neutron pulses (electron bunch width 5 ps) with a short flight path of 7 m. Because of the low instantaneous neutron flux transmission measurements of neutron total cross sections are possible, that exhibit very different beam and back ground conditions than found at other neutron sources.

  16. Photoneutron multiplicities of preactinide nuclei at energies above the pion threshold

    International Nuclear Information System (INIS)

    Arruda-Neto, J.D.T.; Simionatto, S.; Likhachev, V.P.; Garcia, F.; Mesa, J.

    1998-01-01

    The average photoneutron multiplicities anti ν of Au, Ta and 182 W were deduced from their previously measured excitation energies anti E x , from 160 to 250 MeV. A combined analysis of these data and those measured at Saclay up to 140 MeV allowed the extraction of information on anti E x at the ''pure evaporation'' and quasideuteron energy regions. A theoretical approach for the study of anti ν above 140 MeV, which incorporates photopion reabsorption processes by two-body, was proposed, allowing a tentative delineation of the pion mean free path in the nucleus. (orig.)

  17. Photoneutron cross sections for {sup 59}Co. Systematic uncertainties of data from various experiments

    Energy Technology Data Exchange (ETDEWEB)

    Varlamov, V.V. [Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics, Moscow (Russian Federation); Davydov, A.I. [Lomonosov Moscow State University, Physics Faculty, Moscow (Russian Federation); Ishkhanov, B.S. [Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics, Moscow (Russian Federation); Lomonosov Moscow State University, Physics Faculty, Moscow (Russian Federation)

    2017-09-15

    Data on partial photoneutron reaction cross sections (γ, 1n), (γ, 2n), and (γ, 3n) for {sup 59}Co obtained in two experiments carried out at Livermore (USA) were analyzed. The sources of radiation in both experiments were the monoenergetic photon beams from the annihilation in flight of relativistic positrons. The total yield was sorted by the neutron multiplicity, taking into account the difference in the neutron energy spectra for different multiplicity. The two quoted studies differ in the method of determining the neutron. Significant systematic disagreements between the results of the two experiments exist. They are considered to be caused by large systematic uncertainties in partial cross sections, since they do not satisfy physical criteria for reliability of the data. To obtain reliable cross sections of partial and total photoneutron reactions a new method combining experimental data and theoretical evaluation was used. It is based on the experimental neutron yield cross section which is rather independent of neutron multiplicity and the transitional neutron multiplicity functions of the combined photonucleon reaction model (CPNRM). The model transitional multiplicity functions were used for the decomposition of the neutron yield cross section into the contributions of partial reactions. The results of the new evaluation noticeably differ from the partial cross sections obtained in the two experimental studies are under discussion. (orig.)

  18. Photo-neutron yields from thin and thick targets irradiated by 2.0 GeV electrons

    International Nuclear Information System (INIS)

    Hee-Seock, Lee; Syuichi, Ban; Toshiya, Sanami; Kazutoshi, Takahashi; Tatsuhiko, Sato; Kazuo, Shin

    2005-01-01

    The photo-neutron yields from thin and thick targets irradiated by high energy electrons were studied. The photo-neutron spectra at 90 deg C relative to the incident 2.0 GeV electrons were measured by the pulsed beam time-of-flight technique using the Pilot-U plastic scintillator and the NE213 liquid scintillator with 2 inches in length and 2 inches in diameter. Targets, from low-Z element (carbon) to high-Z element (bismuth) and with thin (0.5 Xo) and thick (10 Xo) thickness, were used in this study. The differential photo-neutron yields between 2 MeV (mainly 8 MeV) and 400 MeV were obtained. The systematics was studied to make empirical yield terms for shielding application. Recently, the study of the angular distributed yields was conducted at two other observing angles, 48 deg C and 140 deg C. The photo-neutron yields between 8 MeV and 250 MeV were obtained for thick targets. The experimental data were compared with results calculated using the EGS4+PICA3 or the MCNPX 2.5d code. (authors)

  19. Experimental investigation of the photoneutron production out of the high-energy photon fields at linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yeon Su; Yoon, In Ha; Bae, Sun Myeong; Kang, Tae Young; Baek, Geum Mun; Kim, Sung Hwan; Nam, Uk Won; Lee, Jae Jin; Park, Yeong Sik [Dept. of Radiation Oncology, ASAN Medical Center, Seoul (Korea, Republic of)

    2014-12-15

    Photoneutron dose in high-energy photon radiotherapy at linear accelerator increase the risk for secondary cancer. The purpose of this investigation is to evaluate the dose variation of photoneutron with different treatment method, flattening filter, dose rate and gantry angle in radiation therapy with high-energy photon beam (E≥8 MeV). TrueBeam STxTM(Ver1.5, Varian, USA) and Korea Tissue Equivalent Proportional Counter (KTEPC) were used to detect the photoneutron dose out of the high-energy photon field. Complex Patient plans using Eclipse planning system (Version 10.0, Varian, USA) was used to experiment with different treatment technique(IMRT, VMAT), condition of flattening filter and three different dose rate. Scattered photoneutron dose was measured at eight different gantry angles with open field (Field size : 5×5cm). The mean values of the detected photoneutron dose from IMRT and VMAT were 449.7 μSv, 2940.7 μSv. The mean values of the detected photoneutron dose with Flattening Filter(FF) and Flattening Filter Free(FFF) were measured as 2940.7 μSv, 232.0 μSv. The mean values of the photoneutron dose for each test plan (case 1, case 2 and case 3) with FFF at the three different dose rate (400, 1200, 2400 MU/min) were 3242.5 μSv, 3189.4 μSv, 3191.2 μSv with case 1, 3493.2 μSv, 3482.6 μSv, 3477.2 μSv with case 2 and 4592.2 μSv, 4580.0 μSv, 4542.3 μSv with case 3, respectively. The mean values of the photoneutron dose at eight different gantry angles ( 0° , 45°, 90°, 135°, 180°, 225°, 270° , 315°) were measured as 3.2 μSv, 4.3 μSv, 5.3 μSv, 11.3 μSv, 14.7 μSv, 11.2 μSv, 3.7 μSv, 3.0 μSv at 10 MV and as 373.7 μSv, 369.6 μSv, 384.4 μSv, 423.6 μSv, 447.1 μSv, 448.0 μSv, 384.5 μSv, 377.3 μSv at 15MV. As a result, it is possible to reduce photoneutron dose using FFF mode and VMAT method with TrueBeam STxTM. The risk for secondary cancer of the patients will be decreased with continuous evaluation of the photoneutron dose.

  20. Android lietotņu drošības aspekti

    OpenAIRE

    Buļs, Jānis

    2015-01-01

    Darbā pētīta mobilo telefonu pašlaik populārākā operētājsistēma Android un tās lietotņu drošības aspekti. Autors darbā aprakstījis Android lietotņu drošības aspektus – mehānismu lietotnes ietekmes ierobežošanai, lietojot pieejas tiesības. Autors izveidojis lietotni „PermissionTestApp”, kurai tiek piešķirtas visas 152 uz darba izstrādes brīdi Android pieejamās atļaujas. Lietotne tika izstrādāta, izmantojot „Android Studio” un jaunāko Javas versiju, kas bija pieejama uz darba izstrādes br...

  1. Photoneutron strengths in 26Mg at energies of astrophysical interest

    Science.gov (United States)

    deBoer, R. J.; Best, A.; Görres, J.; Smith, K.; Tan, W.; Wiescher, M.; Raut, R.; Rusev, G.; Tonchev, A. P.; Tornow, W.

    2014-05-01

    Background: The 22Ne(α,n)25Mg reaction is an important source of neutrons for s-process nucleosynthesis. The neutron production from the reaction is quite sensitive to the low-energy cross section, which is dominated by narrow resonances. The high level density of the 26Mg compound nucleus above the α separation energy prevents simple extrapolations from higher energy and the high Coulomb barrier makes the direct measurements extremely difficult. For this reason, indirect methods must be employed to study the level properties of 26Mg. Purpose: The current measurement utilizes the reaction 26Mg(γ,n)25Mg to probe the level structure of the 26Mg compound nucleus from the neutron-separation energy at 11.093 MeV up to Ex≈ 12 MeV. Methods: The High-Intensity γ-ray Source of the Triangle Universities Nuclear Laboratory was used to bombard a ˜16 g sample of enriched 26Mg oxide and the resulting decay neutrons were detected with an array of nine liquid scintillator detectors. Neutron time-of-flight peaks with corresponding energies as low as ˜50 keV were detected. An efficiency measurement of the detectors was made at the University of Notre Dame's nuclear science laboratory to energies as low as 45 keV. Results: Five resonances were observed at Eγ = 11.150, 11.289, 11.329, 11.506, and 11.749 MeV and their strengths have been extracted. Conclusion:. The resulting strengths at Eγ = 11.289, 11.329, 11.506, and 11.749 MeV are in good agreement with previous measurements. The strength of the resonance at Eγ = 11.150 MeV is somewhat lower than previously measured but is in reasonable agreement when systematic uncertainties are considered. The results are also consistent with those of 25Mg(n,γ)26Mg studies where a comparison shows that many of the resonances observed here are the result of multiple unresolved narrow resonances.

  2. A study on the photoneutron dose estimation in flattening filter mode and flattening filter free mode for medical linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Oh Nam [Dept. of Radiology, Mokpo Science University, Mokpo (Korea, Republic of); Lim, Cheong Hwan [Dept. of Radiological Science, Hanseo University, Seosan (Korea, Republic of)

    2017-06-15

    In this study, the generation of photoneutrons between the 10 MV FF mode and the FFF mode was evaluated and the amount of photoneutrons generated by the 10 MV and 15 MV energy changes in the FFF mode was evaluated. The generated neutrons were evaluated at 13 measurement points and the KTEPC was used to collect the generated neutrons. 10 MV FF mode was measured at 10 MV FF mode and FFF mode at all measurement points. In the superior direction, 0.455mSv and 0.152mSv were the largest, and more than 33% optical neutron was generated in FF. 10 MV in FFF mode, 15 MV in 15 MV, and 0.402 mSv in the direction of Superior, and 6.9% in the direction.

  3. A radiochemical separation of spallogenic 88Zr in the carrier-free state for radioisotopic photoneutron sources

    International Nuclear Information System (INIS)

    Whipple, R.E.; Grant, P.M.; Daniels, R.J.; Daniels, W.R.; O'Brien, H.A.Jr.

    1976-01-01

    As the precursor of its 88 Y daughter, 88 Zr could be advantageously included in the active component of the 88 Y-Be photoneutron source for several reasons. The spallation of Mo targets with medium-energy protons at LAMPF procedure has been developed to separate radiozirconium from the target material and various spallogenic impurities. 88 Zr can consequently be obtained carrier-free and in quantitative yield. (author)

  4. MCNP5 evaluation of photoneutron production from the Alexandria University 15 MV Elekta Precise medical LINAC.

    Science.gov (United States)

    Abou-Taleb, W M; Hassan, M H; El Mallah, E A; Kotb, S M

    2018-05-01

    Photoneutron production, and the dose equivalent, in the head assembly of the 15 MV Elekta Precise medical linac; operating in the faculty of Medicine at Alexandria University were estimated with the MCNP5 code. Photoneutron spectra were calculated in air and inside a water phantom to different depths as a function of the radiation field sizes. The maximum neutron fluence is 3.346×10 -9 n/cm 2 -e for a 30×30 cm 2 field size to 2-4 cm-depth in the phantom. The dose equivalent due to fast neutron increases as the field size increases, being a maximum of 0.912 ± 0.05 mSv/Gy at depth between 2 and 4 cm in the water phantom for 40×40 cm 2 field size. Photoneutron fluence and dose equivalent are larger to 100 cm from the isocenter than to 35 cm from the treatment room wall. Copyright © 2018 Elsevier Ltd. All rights reserved.

  5. MEDYCYNA, PŁYWANIE I SPRAWNOŚĆ FIZYCZNA, WYBRANE ASPEKTY = MEDICINE, SWIMMING AND PHYSICAL EFFICIENCY, SELECTED ASPECTS

    OpenAIRE

    Ahmad El-Essa; Ewa Zieliński; Kinga Grobelska; Dariusz Skalski

    2018-01-01

    MEDYCYNA, PŁYWANIE I SPRAWNOŚĆ FIZYCZNA, WYBRANE ASPEKTY = MEDICINE, SWIMMING AND PHYSICAL EFFICIENCY, SELECTED ASPECTS Stan zdrowia populacji oraz systemu opieki zdrowotnej w krajach rozwijających się na przykładzie Ghany = Health status and healthcare system condition in developing countries on the Ghana’s example Zarys anatomii i fizjologii narządu wzroku = Outline of anatomy and phisiology of the organ of eyesight Mechaniczne urazy gałki ocznej i ich możliwe powikłania = Mecha...

  6. Pracoholizm w kategoriach deprecjacji pracy pielęgniarki. Wybrane aspekty = Workaholism in categories of nurses’ work depreciation. Chosen aspects

    OpenAIRE

    Stychno, Ewa; Kulczycka, Kinga

    2016-01-01

    Stychno Ewa, Kulczycka Kinga. Pracoholizm w kategoriach deprecjacji pracy pielęgniarki. Wybrane aspekty = Workaholism in categories of nurses’ work depreciation. Chosen aspects. Journal of Education, Health and Sport. 2016;6(10):11-21. eISSN 2391-8306. DOI http://dx.doi.org/10.5281/zenodo.159507 http://ojs.ukw.edu.pl/index.php/johs/article/view/3920 The journal has had 7 points in Ministry of Science and Higher Education parametric evaluation. Part B item 755 (23.12....

  7. Pracoholizm w kategoriach deprecjacji pracy pielęgniarki. Wybrane aspekty = Workaholism in categories of nurses’ work depreciation. Chosen aspects

    OpenAIRE

    Ewa Stychno; Kinga Kulczycka

    2016-01-01

    Stychno Ewa, Kulczycka Kinga. Pracoholizm w kategoriach deprecjacji pracy pielęgniarki. Wybrane aspekty = Workaholism in categories of nurses’ work depreciation. Chosen aspects. Journal of Education, Health and Sport. 2016;6(10):11-21. eISSN 2391-8306. DOI http://dx.doi.org/10.5281/zenodo.159507 http://ojs.ukw.edu.pl/index.php/johs/article/view/3920       The journal has had 7 points in Ministry of Science and Higher Education parametric evaluation. Part B item 755 (23.12.2...

  8. Environmentální aspekty provozu vozů na CNG

    OpenAIRE

    Raiskup, Martin

    2016-01-01

    Tato bakalářská práce je zaměřená na téma environmentální aspekty provozu vozů na CNG. Nejprve je představen zemní plyn jako palivo pro spalovací motory. Jsou zhodnoceny jeho výhody a nevýhody. Dále jsou popsány jednotlivé spalovací systémy a komponenty motoru na stlačený zemní plyn. Hlavní část práce je zaměřená na ekologii. Je popsán vliv na životní prostředí u spalování stlačeného zemního plynu v porovnání s konvenčními palivy. Toto porovnání je provedeno také podle objektivnější Well to W...

  9. {sup 124}Sb–Be photo-neutron source for BNCT: Is it possible?

    Energy Technology Data Exchange (ETDEWEB)

    Golshanian, Mohadeseh [Nuclear Science and Technology Research Institute (NSTRI), Tehran (Iran, Islamic Republic of); Department of Physics, Shahrood University, Shahrood (Iran, Islamic Republic of); Rajabi, Ali Akbar [Department of Physics, Shahrood University, Shahrood (Iran, Islamic Republic of); Kasesaz, Yaser, E-mail: ykasesaz@aeoi.org.ir [Nuclear Science and Technology Research Institute (NSTRI), Tehran (Iran, Islamic Republic of)

    2016-11-01

    In this research a computational feasibility study has been done on the use of {sup 124}SbBe photo-neutron source for Boron Neutron Capture Therapy (BNCT) using MCNPX Monte Carlo code. For this purpose, a special beam shaping assembly has been designed to provide an appropriate epithermal neutron beam suitable for BNCT. The final result shows that using 150 kCi of {sup 124}Sb, the epithermal neutron flux at the designed beam exit is 0.23×10{sup 9} (n/cm{sup 2} s). In-phantom dose analysis indicates that treatment time for a brain tumor is about 40 min which is a reasonable time. This high activity {sup 124}Sb could be achieved using three 50 kCi rods of {sup 124}Sb which can be produced in a research reactor. It is clear, that as this activity is several hundred times the activity of a typical cobalt radiotherapy source, issues related to handling, safety and security must be addressed.

  10. Study on the photoneutrons produced in 15 MV medical linear accelerators : Comparison of three dimensional conformal radiotherapy and intensity modulated radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Oh Nam [Gangneung Asan Hospital, Gangneung (Korea, Republic of); Yang, Oh Nam; Lim, Cheong Hwan [Hanseo Univ., Seosan (Korea, Republic of)

    2012-12-15

    Intensity-modulated radiotherapy(IMRT) have the ability to provide better dose conformity and sparing of critical normal tissues than three-dimensional radiotherapy(3DCRT). Especially, with the benefit of health insurance in 2011, its use now increasingly in many modern radiotherapy departments. Also the use of linear accelerator with high-energy photon beams over 10 MV is increasing. As is well known, these linacs have the capacity to produce photoneutrons due to photonuclear reactions in materials with a large atomic number such as the target, flattening filters, collimators, and multi-leaf collimators(MLC). MLC-based IMRT treatments increase the monitor units and the probability of production of photoneutrons from photon-induced nuclear reactions. The purpose of this study is to quantitatively evaluate the dose of photoneutrons produced from 3DCRT and IMRT technique for Rando phantom in cervical cancer. We performed the treatment plans with 3DCRT and IMRT technique using Rando phantom for treatment of cervical cancer. An Rando phantom placed on the couch in the supine position was irradiated using 15 MV photon beams. Optically stimulated luminescence dosimeters(OSLD) were attached to 4 different locations (abdomen, chest, head and neck, eyes) and from center of field size and measured 5 times each of locations. Measured neutron dose from IMRT technique increased by 9.0, 8.6, 8.8, and 14 times than 3DCRT technique for abdomen, chest, head and neck, and eyes, respectively. When using IMRT with 15 MV photon beams, the photoneutrons contributed a significant portion on out-of-field. It is difficult to prevent high energy photon beams to produce the photoneutrons due to physical properties, if necessary, It is difficult to prevent high energy photon beams to produce the photoneutrons due to physical properties, if necessary, it is need to provide the additional safe shielding on a linear accelerator and should therefore reduce the out-of-field dose.

  11. Study on the photoneutrons produced in 15 MV medical linear accelerators : Comparison of three dimensional conformal radiotherapy and intensity modulated radiotherapy

    International Nuclear Information System (INIS)

    Yang, Oh Nam; Yang, Oh Nam; Lim, Cheong Hwan

    2012-01-01

    Intensity-modulated radiotherapy(IMRT) have the ability to provide better dose conformity and sparing of critical normal tissues than three-dimensional radiotherapy(3DCRT). Especially, with the benefit of health insurance in 2011, its use now increasingly in many modern radiotherapy departments. Also the use of linear accelerator with high-energy photon beams over 10 MV is increasing. As is well known, these linacs have the capacity to produce photoneutrons due to photonuclear reactions in materials with a large atomic number such as the target, flattening filters, collimators, and multi-leaf collimators(MLC). MLC-based IMRT treatments increase the monitor units and the probability of production of photoneutrons from photon-induced nuclear reactions. The purpose of this study is to quantitatively evaluate the dose of photoneutrons produced from 3DCRT and IMRT technique for Rando phantom in cervical cancer. We performed the treatment plans with 3DCRT and IMRT technique using Rando phantom for treatment of cervical cancer. An Rando phantom placed on the couch in the supine position was irradiated using 15 MV photon beams. Optically stimulated luminescence dosimeters(OSLD) were attached to 4 different locations (abdomen, chest, head and neck, eyes) and from center of field size and measured 5 times each of locations. Measured neutron dose from IMRT technique increased by 9.0, 8.6, 8.8, and 14 times than 3DCRT technique for abdomen, chest, head and neck, and eyes, respectively. When using IMRT with 15 MV photon beams, the photoneutrons contributed a significant portion on out-of-field. It is difficult to prevent high energy photon beams to produce the photoneutrons due to physical properties, if necessary, It is difficult to prevent high energy photon beams to produce the photoneutrons due to physical properties, if necessary, it is need to provide the additional safe shielding on a linear accelerator and should therefore reduce the out-of-field dose

  12. Test calculations of photoneutrons emission from surface of uranium sphere irradiated by 28 MeV electrons

    International Nuclear Information System (INIS)

    Blokhin, A.I.; Degtyarev, I.I.

    2002-01-01

    In this paper the results of physical verification for the BOFOD photonuclear data files are reported, available for the uranium isotopes U 235 , U 238 . These results were compared with calculated data by the parameterization driven model of photonuclear reaction and experimental data. Experimental data of photoneutron yields from surface of uranium sphere irradiated by 28 MeV electrons are used for a verification. Both calculations have been carried out with the RTS and T general purpose Monte Carlo code with detailed electron-photon-nucleon transport simulation using the ENDF/B-VI and EPDL evaluated data libraries

  13. Spectra and absorbed dose by photo-neutrons in a solid water mannequin exposed to a Linac of 15 MV

    International Nuclear Information System (INIS)

    Benites R, J.; Vega C, H. R.; Velazquez F, J.

    2012-10-01

    Using Monte Carlo methods was modeled a solid water mannequin; according to the ICRU 44 (1989), Tissue substitutes in radiation dosimetry and measurements, of the International Commission on Radiation Units and Measurements; Report 44. This material Wt 1 is made of H (8.1%), C (67.2%), N (2.4%), O (19.9%), Cl (0.1%), Ca (2.3%) and its density is of 1.02 gr/cm 3 . The mannequin was put instead of the patient, inside the treatment room and the spectra and absorbed dose were determined by photo-neutrons exposed to a Linac of 15 MV. (Author)

  14. Electron accelerator-based production of molybdenum-99: Bremsstrahlung and photoneutron generation from molybdenum vs. tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Tsechanski, A. [Ben-Gurion University of the Negev, Department of Nuclear Engineering, P.O. Box 653, Beer-Sheva 84105 (Israel); Bielajew, A.F. [Department of Nuclear Engineering and Radiological Sciences, The University of Michigan, 2355 Bonisteel Boulevard, Ann Arbor, MI 48109 (United States); Archambault, J.P.; Mainegra-Hing, E. [National Research Council of Canada, Ionizing Radiation Standards Laboratory, Ottawa, ON K1A 0R6 (Canada)

    2016-01-01

    A new “one-stage” approach for production of {sup 99}Mo and other radioisotopes by means of an electron linear accelerator is described. It is based on using a molybdenum target both as a bremsstrahlung converter and as a radioisotope producing target for the production of {sup 99}Mo via the photoneutron reaction {sup 100}Mo(γ,n){sup 99}Mo. Bremsstrahlung characteristics, such as bremsstrahlung efficiency, angular distribution, and energy deposition for molybdenum targets were obtained by means of the EGSnrc Monte Carlo simulation code system. As a result of our simulations, it is concluded that a 60 MeV electron beam incident on a thick Mo target will have greater bremsstrahlung efficiency than the same thickness (in units of r{sub 0}) W target, for target thickness z > 1.84r{sub 0}, where r{sub 0} is the electron range. A 50 MeV electron beam incident on a Mo target will result in greater bremsstrahlung efficiency than the same thickness W target (in units of r{sub 0}) for target thickness case: z ⩾ 2.0r{sub 0}. It is shown for the one-stage approach with thicknesses of (1.84–2.0)r{sub 0}, that the {sup 99}Mo-production bremsstrahlung efficiency of a molybdenum target is greater by ∼100% at 30 MeV and by ∼70% at 60 MeV compared to the values for tungsten of the same thickness (in units of the appropriate r{sub 0}) in the traditional two-stage approach (W converter and separate {sup 99}Mo producing target). This advantage of the one-stage approach arises from the fact that the bremsstrahlung produced is attenuated only once from attenuation in the molybdenum converter/target. In the traditional, two-stage approach, the bremsstrahlung generated in the W-converter/target is attenuated both in the converter in the {sup 99}Mo-producing molybdenum target. The photoneutron production yield of molybdenum and tantalum (as a substitute for tungsten) target was calculated by means of the MCNP5 transport code. On the basis of these data, the specific activity

  15. Photoneutron Flux Measurement via Neutron Activation Analysis in a Radiotherapy Bunker with an 18 MV Linear Accelerator

    Science.gov (United States)

    Çeçen, Yiğit; Gülümser, Tuğçe; Yazgan, Çağrı; Dapo, Haris; Üstün, Mahmut; Boztosun, Ismail

    2017-09-01

    In cancer treatment, high energy X-rays are used which are produced by linear accelerators (LINACs). If the energy of these beams is over 8 MeV, photonuclear reactions occur between the bremsstrahlung photons and the metallic parts of the LINAC. As a result of these interactions, neutrons are also produced as secondary radiation products (γ,n) which are called photoneutrons. The study aims to map the photoneutron flux distribution within the LINAC bunker via neutron activation analysis (NAA) using indium-cadmium foils. Irradiations made at different gantry angles (0°, 90°, 180° and 270°) with a total of 91 positions in the Philips SLI-25 linear accelerator treatment room and location-based distribution of thermal neutron flux was obtained. Gamma spectrum analysis was carried out with high purity germanium (HPGe) detector. Results of the analysis showed that the maximum neutron flux in the room occurred at just above of the LINAC head (1.2x105 neutrons/cm2.s) which is compatible with an americium-beryllium (Am-Be) neutron source. There was a 90% decrease of flux at the walls and at the start of the maze with respect to the maximum neutron flux. And, just in front of the LINAC door, inside the room, neutron flux was measured less than 1% of the maximum.

  16. Improvement of photoneutron spectrum measurement produced by bombardment of 2 GeV electrons above giant dipole resonance region

    International Nuclear Information System (INIS)

    Lee, H. S.; Park, J. S.; Choi, H. D.; Sato, Tatsuhiko; Shin, Kasuo; Ban, Syuichi

    2000-01-01

    Above the Giant Dipole Resonance (GDR) region, high energy photoneutron spectra produced by irradiation of 2.04 GeV electrons into Pb target were measured by Time-of-Flight (TOF) technique. The differential photoneutron yields were obtained at a fixed angle of 90 degrees to the electron beam direction. The TOF system consists of Pilot-U plastic scintillation detector, which has fast response time, and the high speed multiscaler or CAMAC TDC. In the improvement of experimental setup to extend the flight distance to 10.4 m lead to make the measurable energy to 500 MeV from 300 MeV. And using the TDC based electronics lead to use a veto counter. The results were compared with the calculated one by using EGS4 and Modified PICA95. The characteristics of this TOF system was introduced in this paper and the results for several measuring conditions, which are flight distance, TOF electronics, and type of neutron detector, were discussed to improve the accuracy of this measurement

  17. An MCNP-based model for the evaluation of the photoneutron dose in high energy medical electron accelerators.

    Science.gov (United States)

    Carinou, Eleutheria; Stamatelatos, Ion Evangelos; Kamenopoulou, Vassiliki; Georgolopoulou, Paraskevi; Sandilos, Panayotis

    The development of a computational model for the treatment head of a medical electron accelerator (Elekta/Philips SL-18) by the Monte Carlo code mcnp-4C2 is discussed. The model includes the major components of the accelerator head and a pmma phantom representing the patient body. Calculations were performed for a 14 MeV electron beam impinging on the accelerator target and a 10 cmx10 cm beam area at the isocentre. The model was used in order to predict the neutron ambient dose equivalent at the isocentre level and moreover the neutron absorbed dose distribution within the phantom. Calculations were validated against experimental measurements performed by gold foil activation detectors. The results of this study indicated that the equivalent dose at tissues or organs adjacent to the treatment field due to photoneutrons could be up to 10% of the total peripheral dose, for the specific accelerator characteristics examined. Therefore, photoneutrons should be taken into account when accurate dose calculations are required to sensitive tissues that are adjacent to the therapeutic X-ray beam. The method described can be extended to other accelerators and collimation configurations as well, upon specification of treatment head component dimensions, composition and nominal accelerating potential.

  18. Photoneutron Flux Measurement via Neutron Activation Analysis in a Radiotherapy Bunker with an 18 MV Linear Accelerator

    Directory of Open Access Journals (Sweden)

    Çeçen Yiğit

    2017-01-01

    Full Text Available In cancer treatment, high energy X-rays are used which are produced by linear accelerators (LINACs. If the energy of these beams is over 8 MeV, photonuclear reactions occur between the bremsstrahlung photons and the metallic parts of the LINAC. As a result of these interactions, neutrons are also produced as secondary radiation products (γ,n which are called photoneutrons. The study aims to map the photoneutron flux distribution within the LINAC bunker via neutron activation analysis (NAA using indium-cadmium foils. Irradiations made at different gantry angles (0°, 90°, 180° and 270° with a total of 91 positions in the Philips SLI-25 linear accelerator treatment room and location-based distribution of thermal neutron flux was obtained. Gamma spectrum analysis was carried out with high purity germanium (HPGe detector. Results of the analysis showed that the maximum neutron flux in the room occurred at just above of the LINAC head (1.2x105 neutrons/cm2.s which is compatible with an americium-beryllium (Am-Be neutron source. There was a 90% decrease of flux at the walls and at the start of the maze with respect to the maximum neutron flux. And, just in front of the LINAC door, inside the room, neutron flux was measured less than 1% of the maximum.

  19. Combined Photoneutron And X Ray Interrogation Of Containers For Nuclear Materials

    Science.gov (United States)

    Gozani, Tsahi; Shaw, Timothy; King, Michael J.; Stevenson, John; Elsalim, Mashal; Brown, Craig; Condron, Cathie

    2011-06-01

    Effective cargo inspection systems for nuclear material detection require good penetration by the interrogating radiation, generation of a sufficient number of fissions, and strong and penetrating detection signatures. Inspection systems need also to be sensitive over a wide range of cargo types and densities encountered in daily commerce. Thus they need to be effective with highly hydrogenous cargo, where neutron attenuation is a major limitation, as well as with dense metallic cargo, where x-ray penetration is low. A system that interrogates cargo with both neutrons and x-rays can, in principle, achieve high performance over the widest range of cargos. Moreover, utilizing strong prompt-neutron (˜3 per fission) and delayed-gamma ray (˜7 per fission) signatures further strengthens the detection sensitivity across all cargo types. The complementary nature of x-rays and neutrons, used as both probing radiation and detection signatures, alleviates the need to employ exceedingly strong sources, which would otherwise be required to achieve adequate performance across all cargo types, if only one type of radiation probe were employed. A system based on the above principles, employing a commercially-available 9 MV linac was developed and designed. Neutrons are produced simultaneously with x-rays by the photonuclear interaction of the x-ray beam with a suitable converter. A total neutron yield on the order of 1011 n/s is achieved with an average electron beam current of 100 μA. If fissionable material is present, fissions are produced both by the high-energy x-ray beam and by the photoneutrons. Photofission and neutron fission dominate in hydrogenous and metallic cargos, respectively. Neutron-capture gamma rays provide information on the cargo composition. The prompt neutrons resulting from fission are detected by two independent detector systems: by very efficient Differential Die Away Analysis (DDAA) detectors, and by direct detection of neutrons with energies higher

  20. Photons and photoneutrons spectra of a Linac of 15 MV; Espectros de fotones y fotoneutrones de un LINAC de 15 MV

    Energy Technology Data Exchange (ETDEWEB)

    Benites R, J. L.; Carrillo C, A. [Centro Estatal de Cancerologia de Nayarit, Av. Enfermeria, Fracc. Fray Junipero Serra, 63000 Tepic, Nayarit (Mexico); Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Velazquez F, J. B., E-mail: jlbenitesr@prodigy.net.mx [Universidad Autonoma de Nayarit, Posgrado CBAP, Carretera Tepic Compostela Km. 9, Xalisco, Nayarit (Mexico)

    2011-10-15

    Using the Monte Carlo code MCNP-5, the photons and photoneutrons spectra generated in the head stock of the lineal accelerator (Linac) Varian of 15 MV of the Cancerology State of Nayarit were determined. For the calculations a heterogeneous head stock was modeled, more compatible with the work conditions. In the center of the head stock a tungsten target was located on a copper support, followed by the flattened filter. The photons and photoneutrons spectra were obtained accelerating electrons and making them collide against the target to produce photons by Bremsstrahlung, these photons were transported inside the head stock and the photons and photoneutrons spectra were calculated in a punctual detector located under the flattened filter and in the isocenter. The spectra were evaluated in punctual detectors that were located in the plane from the isocenter to the long of the X and Y axes each 20 cm, in an equidistant way, up to 2 m, so much in the longitudinal and transversal axes. In the calculations were used histories 5E(6) with the purpose of obtaining smaller uncertainties to 1%. It was found that the photons spectrum in the punctual detector inside the head stock presents a pick of 1.25 MeV in the energy interval of 0.5 and 1.5 MeV, later suffers a filtration and diminishes in asymptote form. This spectrum modifies when the beam reaches the isocenter, diminishing the low energy photons. Inside the head stock the photoneutrons spectrum shows a structure with two picks, one before 1 MeV and other after 1 MeV; this is for effect of the collimators geometry and the distance. Finally an increment of the total neutrons flow to 60 cm of distance of the isocenter on the Y axis was observed, due to the design geometry of the modeling heterogeneous head stock. (Author)

  1. Angular distribution measurements of photo-neutron yields produced by 2.0 GeV electrons incident on thick targets

    International Nuclear Information System (INIS)

    Lee, H. S.; Ban, S.; Sanami, T.; Takahashi, K.; Sato, T.; Shin, K.; Chung, C.

    2005-01-01

    A study of differential photo-neutron yields by irradiation with 2 GeV electrons has been carried out. In this extension of a previous study in which measurements were made at an angle of 90 deg. relative to incident electrons, the differential photo-neutron yield was obtained at two other angles, 48 deg. and 140 deg., to study its angular characteristics. Photo-neutron spectra were measured using a pulsed beam time-of-flight method and a BC418 plastic scintillator. The reliable range of neutron energy measurement was 8-250 MeV. The neutron spectra were measured for 10 Xo-thick Cu, Sn, W and Pb targets. The angular distribution characteristics, together with the previous results for 90 deg., are presented in the study. The experimental results are compared with Monte Carlo calculation results. The yields predicted by MCNPX 2.5 tend to underestimate the measured ones. The same trend holds for the comparison results using the EGS4 and PICA3 codes. (authors)

  2. Angular distribution measurements of photo-neutron yields produced by 2.0 GeV electrons incident on thick targets.

    Science.gov (United States)

    Lee, Hee-Seock; Ban, Syuichi; Sanami, Toshiya; Takahashi, Kazutoshi; Sato, Tatsuhiko; Shin, Kazuo; Chung, Chinwha

    2005-01-01

    A study of differential photo-neutron yields by irradiation with 2 GeV electrons has been carried out. In this extension of a previous study in which measurements were made at an angle of 90 degrees relative to incident electrons, the differential photo-neutron yield was obtained at two other angles, 48 degrees and 140 degrees, to study its angular characteristics. Photo-neutron spectra were measured using a pulsed beam time-of-flight method and a BC418 plastic scintillator. The reliable range of neutron energy measurement was 8-250 MeV. The neutron spectra were measured for 10 Xo-thick Cu, Sn, W and Pb targets. The angular distribution characteristics, together with the previous results for 90 degrees, are presented in the study. The experimental results are compared with Monte Carlo calculation results. The yields predicted by MCNPX 2.5 tend to underestimate the measured ones. The same trend holds for the comparison results using the EGS4 and PICA3 codes.

  3. LTV1 raidījuma „Aizliegtais paņēmiens” ētiskie aspekti

    OpenAIRE

    Zeikate, Ieva

    2015-01-01

    Bakalaura darba tēma ir LTV1 Raidījuma „Aizliegtais paľēmiens” ētiskie aspekti. Darba mērķis ir izpētīt raidījuma saturu, noskaidrot, vai tajā tiek ievēroti ţurnālistikas ētikas principi un vērtības, noteikt raidījuma mērķus un izmantotos līdzekļus, kā arī to saskaľotību, veicot raidījuma izpēti aptuveni gada garumā. Teorija balstīta par televīziju, pētnieciskās ţurnālistikas teorētisko raksturojumu, ētiku un ţurnālistikas ētikas pamatprincipiem. Izvēlētās pētniecības metodes i...

  4. Bremsstrahlung pair-production of positrons with low neutron background

    International Nuclear Information System (INIS)

    Lessner, E.

    1998-01-01

    Minimization of component activation is highly desirable at accelerator-based positron sources. Electrons in the 8- to 14-MeV energy range impinging on a target produce photons energetic enough to create electron-positron pairs; however, few of the photons are energetic enough to produce photoneutrons. Slow positron production by low-energy electrons impinging on a multilayer tungsten target with and without electromagnetic extraction between the layers was studied by simulation. The neutron background from 14-MeV electrons is expected to be significantly lower than that encountered with higher-energy electron beams. Numerical results are presented and some ideas for a low-activation slow-positron source are discussed

  5. MCNP6 unstructured mesh application to estimate the photoneutron distribution and induced activity inside a linac bunker

    Science.gov (United States)

    Juste, B.; Morató, S.; Miró, R.; Verdú, G.; Díez, S.

    2017-08-01

    Unwanted neutrons in radiation therapy treatments are typically generated by photonuclear reactions. High-energy beams emitted by medical Linear Accelerators (LinAcs) interact with high atomic number materials situated in the accelerator head and release neutrons. Since neutrons have a high relative biological effectiveness, even low neutron doses may imply significant exposure of patients. It is also important to study radioactivity induced by these photoneutrons when interacting with the different materials and components of the treatment head facility and the shielding room walls, since persons not present during irradiation (e.g. medical staff) may be exposed to them even when the accelerator is not operating. These problems are studied in this work in order to contribute to challenge the radiation protection in these treatment locations. The work has been performed by simulation using the latest state of the art of Monte-Carlo computer code MCNP6. To that, a detailed model of particles transport inside the bunker and treatment head has been carried out using a meshed geometry model. The LinAc studied is an Elekta Precise accelerator with a treatment photon energy of 15 MeV used at the Hospital Clinic Universitari de Valencia, Spain.

  6. Photoneutron cross sections measurements in 9Be, 13C e 17O with thermal neutron capture gamma-rays

    International Nuclear Information System (INIS)

    Semmler, Renato

    2006-01-01

    Photoneutron cross sections measurements of 9 Be, 13 C and 17 O have been obtained in the energy interval between 1,6 and 10,8 MeV, using neutron capture gamma-rays with high resolution in energy (3 a 21 eV), produced by 21 target materials, placed inside a tangential beam port, near the core of the IPEN/CNEN-SP IEA-R1 (5 MW) research reactor. The samples have been irradiated inside a 4π geometry neutron detector system 'Long Counter', 520,5 cm away from the capture target. The capture gamma-ray flux was determined by means of the analysis of the gamma spectrum obtained by using a Ge(Li) solid-state detector (EG and G ORTEC, 25 cm 3 , 5%), previously calibrated with capture gamma-rays from a standard target of Nitrogen (Melamine). The neutron photoproduction cross section has been measured for each target capture gamma-ray spectrum (compound cross section). A inversion matrix methodology to solve inversion problems for unfolding the set of experimental compound cross sections, was used in order to obtain the cross sections at specific excitation energy values (principal gamma line energies of the capture targets). The cross sections obtained at the energy values of the principal gamma lines were compared with experimental data reported by other authors, with have employed different gamma-ray sources. A good agreement was observed among the experimental data in this work with reported in the literature. (author)

  7. Analysis of the Photoneutron Yield and Thermal Neutron Flux in an Unreflected Electron Accelerator-Driven Neutron Source

    International Nuclear Information System (INIS)

    Dale, Gregory E.; Gahl, John M.

    2005-01-01

    There are several potential uses for a high-flux thermal neutron source in both industrial and clinical applications. The viable commercial implementation of these applications requires a low-cost, high-flux thermal neutron generator suitable for installation in industrial and clinical environments. This paper describes the Monte Carlo for N-Particle modeling results of a high-flux thermal neutron source driven with an electron accelerator. An electron linear accelerator (linac), fitted with a standard X-ray converter, can produce high neutron yields in materials with low photonuclear threshold energies, such as D and 9 Be. Results indicate that a 10-MeV, 10-kW electron linac can produce on the order of 10 12 n/s in a heavy water photoneutron target. The thermal neutron flux in an unreflected heavy water target is calculated to be on the order of 10 10 n.cm -2 .s. The sensitivity of these answers to heavy water purity is also investigated, specifically the dilution of heavy water with light water. It is shown that the peak thermal neutron flux is not adversely effected by dilution up to a light water weight fraction of 35%

  8. Measurementof photo-neutron dose from an 18-MV medical linac using a foil activation method in view of radiation protection of patients

    International Nuclear Information System (INIS)

    Yuecel, Haluk; Kolbasi, Asuman; Yueksel, Alptug Oezer; Cobanbas, Ibrahim; Kaya, Vildan

    2016-01-01

    High-energy linear accelerators are increasingly used in the medical field. However, the unwanted photo-neutrons can also be contributed to the dose delivered to the patients during their treatments. In this study, neutron fluxes were measured in a solid water phantom placed at the isocenter 1-m distance from the head of an 18-MV linac using the foil activation method. The produced activities were measured with a calibrated well-type Ge detector. From the measured fluxes, the total neutron fluence was found to be (1.17 ± 0.06) X 10 7 n/cm 2 per Gy at the phantom surface in a 20 X 20 cm 2 X-ray field size. The maximum photo-neutron dose was measured to be 0.67 ± 0.04 mSv/Gy at d max = 5 cm depth in the phantom at isocenter. The present results are compared with those obtained for different field sizes of 10 X 10cm 2 , 15 X 15cm 2 , and 20 X 20cm 2 from 10-, 15-, and 18-MV linacs. Additionally, ambient neutron dose equivalents were determined at different locations in the room and they were found to be negligibly low. The results indicate that the photo-neutron dose at the patient position is not a negligible fraction of the therapeutic photon dose. Thus, there is a need for reduction of the contaminated neutron dose by taking some additional measures, for instance, neutron absorbing-protective materials might be used as aprons during the treatment

  9. Kulturologiczne aspekty życia rodzinnego Vuka Karadžicia w świetle jego korespondencji

    Directory of Open Access Journals (Sweden)

    Sylwia Nowak-Bajcar

    2017-10-01

    Full Text Available Cultural aspects of Vuk Karadžić’s family life in the light of his correspondence The source material for the study, which is the correspondence between Anna and Vuk Karadžić, spouses coming from different cultures, was used to highlight the issues of legitimacy of the fear of cultural difference of the Orient. The cultural sphere of family life (manifested in particular by the status of the child becomes herein an excuse to touch upon the question of whether and to what extent the legal system governing family relations in Serbia after the period of the Ottoman rule was different from the civil codes in Western Europe.   Kulturologiczne aspekty życia rodzinnego Vuka Karadžicia w świetle jego korespondencji Materiał źródłowy, jakim jest korespondencja Anny i Vuka Karadžiciów, małżonków wywodzących się z odmiennych kręgów kulturowych, posłużył do wydobycia problematyki zasadności lęku „Zachodu” przed odmiennością kulturową Orientu. Sfera kultury życia rodzinnego (manifestowana szczególnie poprzez status dziecka stanowi w niniejszym tekście pretekst do postawienia pytania o to, czy i w jakiej mierze system prawny regulujący relacje rodzinne w potureckiej Serbii odbiegał od kodeksów cywilnych na Zachodzie Europy.

  10. Background Material

    DEFF Research Database (Denmark)

    Zandersen, Marianne; Hyytiäinen, Kari; Saraiva, Sofia

    This document serves as a background material to the BONUS Pilot Scenario Workshop, which aims to develop harmonised regional storylines of socio-ecological futures in the Baltic Sea region in a collaborative effort together with other BONUS projects and stakeholders.......This document serves as a background material to the BONUS Pilot Scenario Workshop, which aims to develop harmonised regional storylines of socio-ecological futures in the Baltic Sea region in a collaborative effort together with other BONUS projects and stakeholders....

  11. Background radiation

    International Nuclear Information System (INIS)

    Arnott, D.

    1985-01-01

    The effects of background radiation, whether natural or caused by man's activities, are discussed. The known biological effects of radiation in causing cancers or genetic mutations are explained. The statement that there is a threshold below which there is no risk is examined critically. (U.K.)

  12. The analysis and evaluation by the method of reduction of total photoneutron reaction cross sections in the range of giant dipole resonance

    International Nuclear Information System (INIS)

    Varlamov, V.V.; Efimkin, N.G.; Ishkhanov, B.S.; Sapunenko, V.V.; Stepanov, M.E.

    1993-01-01

    The method based on the method of reduction is proposed for the evaluation of photonuclear reaction cross sections have been obtained at significant systematic uncertainties (different apparatus functions, calibration and normalization uncertainties). The evaluation method consists of using the real apparatus function (photon spectrum) of each individual experiment to reduce the data to a representation generated by an apparatus function of better quality. The task is to find the most reasonably achievable monoenergetic representation (MRAMR) of the information about cross section contained in different experiment observables and to take into account the experimental uncertainties of calibration and normalization procedures. The method was used to obtain the evaluated total photoneutron (γ, xn) reaction cross sections for 16 O, 28 Si, nat Cu, 141 Pr, and 208 Pb are presented. 79 refs., 19 figs., 6 tabs

  13. Cross sections of photoneutron reactions on /sup 64/,/sup 66/,/sup 68/n, /sup 70/,/sup 72/,/sup 74/,/sup 76/Ge, /sup 76/,/sup 78/,/sup 80/,/sup 82/Se

    Energy Technology Data Exchange (ETDEWEB)

    Goryachev, A M; Zalesnyi, G N [Saratovskii Gosudarstvennyi Univ. (USSR); Tulupov, B A [AN SSSR, Moscow. Inst. Yadernykh Issledovanii

    1975-01-01

    Photoneutron cross-sections for /sup 64/,/sup 66/,/sup 68/Zn, /sup 70/,/sup 72/,/sup 74/,/sup 76/Ge, and /sup 76/,/sup 78/,/sup 80/,/sup 82/Se nuclei from the threshold energy to 24 MeV with 0.2 MeV step have been measured. Results of the experiment are compared to predictions of the collective dynamical model of a giant resonance.

  14. Spectra and absorbed dose by photo-neutrons in a solid water mannequin exposed to a Linac of 15 MV; Espectros y dosis absorbida por fotoneutrones en un maniqui de agua solida expuesta a una Linac de 15 MV

    Energy Technology Data Exchange (ETDEWEB)

    Benites R, J. [Centro Estatal de Cancerologia de Nayarit, Servicio de Seguridad Radiologica, Calz. de la Cruz 118 Sur, 63000 Tepic, Nayarit (Mexico); Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Apdo. Postal 336, 98000 Zacatecas (Mexico); Velazquez F, J., E-mail: jlbenitesr@prodigy.net.mx [Universidad Autonoma de Nayarit, Posgrado en Ciencias Biologico Agropecuarias, Carretera Tepic-Compostela Km 9, 63780 Jalisco-Nayarit (Mexico)

    2012-10-15

    Using Monte Carlo methods was modeled a solid water mannequin; according to the ICRU 44 (1989), Tissue substitutes in radiation dosimetry and measurements, of the International Commission on Radiation Units and Measurements; Report 44. This material Wt 1 is made of H (8.1%), C (67.2%), N (2.4%), O (19.9%), Cl (0.1%), Ca (2.3%) and its density is of 1.02 gr/cm{sup 3}. The mannequin was put instead of the patient, inside the treatment room and the spectra and absorbed dose were determined by photo-neutrons exposed to a Linac of 15 MV. (Author)

  15. Experimental apparatus with {sup 3}He detectors for photoneutron measurements greater than 8 MV; Aparato experimental de detector {sup 3}He, para medida fotonêutrons em acelerador com energia acima 8 MV

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Marcelo Vilela da; Fontes, Gladson Silva; Cardoso, Domingos D’Oliveira, E-mail: marcelovilelasilva@gmail.com [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil)

    2017-07-01

    Particle technology has a profound impact on society. Its applications are well established mainly in the treatment of cancer and other diseases. The objective of this work was to develop an experimental apparatus with {sup 3}He detectors for photoneutron measurements greater than 8 MV. The apparatus allowed to obtain a multi energetic neutron measurements with detector and changing the different thicknesses of shields and for different dose rates. Additionally, an analytical model was developed, based on the approximation of the diffusion, for two groups of energy. The results indicated an increasing and linear behavior in the detector response. (author)

  16. Photo-neutron reaction cross-section for 93Nb in the end-point bremsstrahlung energies of 12–16 and 45–70 MeV

    International Nuclear Information System (INIS)

    Naik, H.; Kim, G.N.; Schwengner, R.; Kim, K.; Zaman, M.; Tatari, M.; Sahid, M.; Yang, S.C.; John, R.; Massarczyk, R.; Junghans, A.; Shin, S.G.; Key, Y.; Wagner, A.; Lee, M.W.; Goswami, A.; Cho, M.-H.

    2013-01-01

    The photo-neutron cross-sections of 93 Nb at the end-point bremsstrahlung energies of 12, 14 and 16 MeV as well as 45, 50, 55, 60 and 70 MeV have been determined by the activation and the off-line γ-ray spectrometric techniques using the 20 MeV electron linac (ELBE) at Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden, Germany, and 100 MeV electron linac at Pohang Accelerator Laboratory (PAL), Pohang, Korea. The 93 Nb(γ, xn, x=1–4) reaction cross-sections as a function of photon energy were also calculated using computer code TALYS 1.4. The flux-weighted average values were obtained from the experimental and the theoretical (TALYS) values based on mono-energetic photons. The experimental values of present work are in good agreement with the flux-weighted theoretical values of TALYS 1.4 but are slightly higher than the flux-weighted experimental data of mono-energetic photons. It was also found that the theoretical and the experimental values of present work and literature data for the 93 Nb(γ, xn) reaction cross-sections increase from the threshold values to a certain energy, where other reaction channels opens. However, the increase of 93 Nb(γ, n) and 93 Nb(γ, 2n) reaction cross-sections are sharper compared to 93 Nb(γ, 3n) and 93 Nb(γ, 4n) reaction cross-sections. The sharp increase of 93 Nb(γ, n) and 93 Nb(γ, 2n) reaction cross-sections from the threshold value up to 17–22 MeV is due to the Giant Dipole Resonance (GDR) effect besides the role of excitation energy. After a certain values, the individual 93 Nb(γ, xn) reaction cross-sections decrease with increase of bremsstrahlung energy due to opening of other reaction channels

  17. Background sources at PEP

    International Nuclear Information System (INIS)

    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, γ-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

  18. Cosmic Microwave Background Timeline

    Science.gov (United States)

    Cosmic Microwave Background Timeline 1934 : Richard Tolman shows that blackbody radiation in an will have a blackbody cosmic microwave background with temperature about 5 K 1955: Tigran Shmaonov anisotropy in the cosmic microwave background, this strongly supports the big bang model with gravitational

  19. Ofšoru izveidošanas un piemērošanas aspekti starptautiskajā tirdzniecībā un nodokļu plānošanā

    OpenAIRE

    Cifanskis, Artjoms

    2012-01-01

    Diplomdarba tēmas nosaukums ir „Ofšoru izveidošanas un piemērošanas aspekti starptautiskajā tirdzniecībā un nodokļu plānošanā”. Diplomdarba mērķis ir izpētīt ofšoru īpašības un beneficiārā īpašuma būtību, kā arī analizēt uz tiem vērstu pretdarbību efektivitāti. Darba pirmajā daļā tika apskatīta vēsturiskā izcelšanās, ofšoru definējums, nodokļu apiešana un izvairīšanās, starptautiskā nodokļu plānošana, beneficiārais īpašums, melnie saraksti un ofšoru klasifikācija, pielietojuma iespējas. Ot...

  20. Optimal background matching camouflage.

    Science.gov (United States)

    Michalis, Constantine; Scott-Samuel, Nicholas E; Gibson, David P; Cuthill, Innes C

    2017-07-12

    Background matching is the most familiar and widespread camouflage strategy: avoiding detection by having a similar colour and pattern to the background. Optimizing background matching is straightforward in a homogeneous environment, or when the habitat has very distinct sub-types and there is divergent selection leading to polymorphism. However, most backgrounds have continuous variation in colour and texture, so what is the best solution? Not all samples of the background are likely to be equally inconspicuous, and laboratory experiments on birds and humans support this view. Theory suggests that the most probable background sample (in the statistical sense), at the size of the prey, would, on average, be the most cryptic. We present an analysis, based on realistic assumptions about low-level vision, that estimates the distribution of background colours and visual textures, and predicts the best camouflage. We present data from a field experiment that tests and supports our predictions, using artificial moth-like targets under bird predation. Additionally, we present analogous data for humans, under tightly controlled viewing conditions, searching for targets on a computer screen. These data show that, in the absence of predator learning, the best single camouflage pattern for heterogeneous backgrounds is the most probable sample. © 2017 The Authors.

  1. Wybrane aspekty wielorakiego znaczenia bytu i intencjonalności w ujęciu Franza Brentana i Martina Heideggera

    Directory of Open Access Journals (Sweden)

    Sonia KAMIŃSKA

    2013-12-01

    Full Text Available The text aims to acquaint the Reader with Franz Brentano’s doctoral dissertation Von der mannigfachen Bedeutung des Seienden nach Aristoteles (1862, which opens the Aristotelica series and that is known to have inspired young Heidegger to become a philosopher. The text analyses the nature and scope of this inspiration. The first part tells the story of the book’s origin and tries to provide a bigger picture for Heidegger’s acquaintance with Brentano’s philosophy as well as presenting him against the background of Brentano’s other students (Kazimierz Twardowski, Edmund Husserl, Alexius Meinong, Carl Stumpf, Anton Marty, et al.. The second part describes the famous 15 theses on being, which are the heart of the book On the Several Senses of Being in Aristotle, and thus enables a comparison of Brentano’s Thomistic ontology with the fundamental ontology of Heidegger. And this comparison is the subject of part three, which also tries to verify to what extent Heidegger was in fact indebted to Brentano and whether we can call him a “brentanist” at all.

  2. Cosmic microwave background radiation

    International Nuclear Information System (INIS)

    Wilson, R.W.

    1979-01-01

    The 20-ft horn-reflector antenna at Bell Laboratories is discussed in detail with emphasis on the 7.35 cm radiometer. The circumstances leading to the detection of the cosmic microwave background radiation are explored

  3. Zambia Country Background Report

    DEFF Research Database (Denmark)

    Hampwaye, Godfrey; Jeppesen, Søren; Kragelund, Peter

    This paper provides background data and general information for the Zambia studies focusing on local food processing sub­‐sector; and the local suppliers to the mines as part of the SAFIC project (Successful African Firms and Institutional Change).......This paper provides background data and general information for the Zambia studies focusing on local food processing sub­‐sector; and the local suppliers to the mines as part of the SAFIC project (Successful African Firms and Institutional Change)....

  4. The natural radiation background

    International Nuclear Information System (INIS)

    Duggleby, J.C.

    1982-01-01

    The components of the natural background radiation and their variations are described. Cosmic radiation is a major contributor to the external dose to the human body whilst naturally-occurring radionuclides of primordial and cosmogenic origin contribute to both the external and internal doses, with the primordial radionuclides being the major contributor in both cases. Man has continually modified the radiation dose to which he has been subjected. The two traditional methods of measuring background radiation, ionisation chamber measurements and scintillation counting, are looked at and the prospect of using thermoluminescent dosimetry is considered

  5. Effects of background radiation

    International Nuclear Information System (INIS)

    Knox, E.G.; Stewart, A.M.; Gilman, E.A.; Kneale, G.W.

    1987-01-01

    The primary objective of this investigation is to measure the relationship between exposure to different levels of background gamma radiation in different parts of the country, and different Relative Risks for leukaemias and cancers in children. The investigation is linked to an earlier analysis of the effects of prenatal medical x-rays upon leukaemia and cancer risk; the prior hypothesis on which the background-study was based, is derived from the earlier results. In a third analysis, the authors attempted to measure varying potency of medical x-rays delivered at different stages of gestation and the results supply a link between the other two estimates. (author)

  6. The cosmic microwave background

    International Nuclear Information System (INIS)

    Silk, J.

    1991-01-01

    Recent limits on spectral distortions and angular anisotropies in the cosmic microwave background are reviewed. The various backgrounds are described, and the theoretical implications are assessed. Constraints on inflationary cosmology dominated by cold dark matter (CDM) and on open cosmological models dominated by baryonic dark matter (BDM), with, respectively, primordial random phase scale-invariant curvature fluctuations or non-gaussian isocurvature fluctuations are described. More exotic theories are addressed, and I conclude with the 'bottom line': what theories expect experimentalists to be measuring within the next two to three years without having to abandon their most cherished theorists. (orig.)

  7. The Cosmic Background Explorer

    Science.gov (United States)

    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.

  8. Thermal background noise limitations

    Science.gov (United States)

    Gulkis, S.

    1982-01-01

    Modern detection systems are increasingly limited in sensitivity by the background thermal photons which enter the receiving system. Expressions for the fluctuations of detected thermal radiation are derived. Incoherent and heterodyne detection processes are considered. References to the subject of photon detection statistics are given.

  9. Berkeley Low Background Facility

    International Nuclear Information System (INIS)

    Thomas, K. J.; Norman, E. B.; Smith, A. R.; Poon, A. W. P.; Chan, Y. D.; Lesko, K. T.

    2015-01-01

    The Berkeley Low Background Facility (BLBF) at Lawrence Berkeley National Laboratory (LBNL) in Berkeley, California provides low background gamma spectroscopy services to a wide array of experiments and projects. The analysis of samples takes place within two unique facilities; locally within a carefully-constructed, low background laboratory on the surface at LBNL and at the Sanford Underground Research Facility (SURF) in Lead, SD. These facilities provide a variety of gamma spectroscopy services to low background experiments primarily in the form of passive material screening for primordial radioisotopes (U, Th, K) or common cosmogenic/anthropogenic products; active screening via neutron activation analysis for U,Th, and K as well as a variety of stable isotopes; and neutron flux/beam characterization measurements through the use of monitors. A general overview of the facilities, services, and sensitivities will be presented. Recent activities and upgrades will also be described including an overview of the recently installed counting system at SURF (recently relocated from Oroville, CA in 2014), the installation of a second underground counting station at SURF in 2015, and future plans. The BLBF is open to any users for counting services or collaboration on a wide variety of experiments and projects

  10. The Cosmic Microwave Background

    Directory of Open Access Journals (Sweden)

    Jones Aled

    1998-01-01

    Full Text Available We present a brief review of current theory and observations of the cosmic microwave background (CMB. New predictions for cosmological defect theories and an overview of the inflationary theory are discussed. Recent results from various observations of the anisotropies of the microwave background are described and a summary of the proposed experiments is presented. A new analysis technique based on Bayesian statistics that can be used to reconstruct the underlying sky fluctuations is summarised. Current CMB data is used to set some preliminary constraints on the values of fundamental cosmological parameters $Omega$ and $H_circ$ using the maximum likelihood technique. In addition, secondary anisotropies due to the Sunyaev-Zel'dovich effect are described.

  11. Psychologiczne aspekty chorób alergicznych: trudności dorosłych pacjentów z astmą oskrzelową i atopowym zapaleniem skóry

    Directory of Open Access Journals (Sweden)

    Paulina Albińska

    2014-12-01

    Full Text Available Celem pracy jest zaprezentowanie przeglądu badań na temat psychologicznego funkcjonowania dorosłych cierpiących na choroby alergiczne. Artykuł koncentruje się na dorosłych ze względu na istnienie małej liczby prac naukowych dotyczących zmiany manifestacji symptomów u pacjentów z wyżej wymienionymi chorobami, która może być traktowana jako pierwsze i ostatnie stadium marszu alergicznego, ponieważ jego objawowa manifestacja u dzieci zwykle przybiera postać atopowego zapalenia skóry, podczas gdy u dorosłych jest znana jako astma oskrzelowa. Analiza odpowiada na pytanie, czy wspólnej, alergiczno-zapalnej etiologii tych schorzeń odpowiadają podobieństwa doświadczanych trudności psychologicznych. Omówienie odwołuje się do polskiej i zagranicznej literatury przedmiotu i uwzględnia kluczowe aspekty chorób psychosomatycznych – astmy i atopowego zapalenia skóry – czyli trudności ze snem, depresję, lęk, inne zaburzenia afektywne, zaburzenia zachowania i trudności poznawcze. Współwystępowanie zaburzeń psychicznych i somatycznych u chorych na alergię to niepodważalny dowód integralności somy i psyche, co rzadko dostrzegają osoby odpowiedzialne za system opieki zdrowotnej. Ignorują one tym samym ważny element procesu diagnostyczno-terapeutycznego, istotny dla wyzdrowienia pacjentów z astmą i atopowym zapaleniem skóry.

  12. Family Background and Entrepreneurship

    DEFF Research Database (Denmark)

    Lindquist, Matthew J.; Sol, Joeri; Van Praag, Mirjam

    Vast amounts of money are currently being spent on policies aimed at promoting entrepreneurship. The success of such policies, however, rests in part on the assumption that individuals are not ‘born entrepreneurs’. In this paper, we assess the importance of family background and neighborhood...... effects as determinants of entrepreneurship. We start by estimating sibling correlations in entrepreneurship. We find that between 20 and 50 percent of the variance in different entrepreneurial outcomes is explained by factors that siblings share. The average is 28 percent. Allowing for differential...... entrepreneurship does play a large role, as do shared genes....

  13. Malaysia; Background Paper

    OpenAIRE

    International Monetary Fund

    1996-01-01

    This Background Paper on Malaysia examines developments and trends in the labor market since the mid-1980s. The paper describes the changes in the employment structure and the labor force. It reviews wages and productivity trends and their effects on unit labor cost. The paper highlights that Malaysia’s rapid growth, sustained since 1987, has had a major impact on the labor market. The paper outlines the major policy measures to address the labor constraints. It also analyzes Malaysia’s recen...

  14. Ambient dose equivalent and personal points due to photoneutrons outside a facility that houses a linear accelerator of 18 MV varian; Equivalente de dosis ambiental y personal debida a fotoneutrones en puntos externos a una instalacion que alberga un acelerador lineal varian de 18 MV

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, S. A.; Barquero, R.; Gomez-Ros, J. M.; Lallena, A. M.; Ponzano, P. E.

    2011-07-01

    The use of linear accelerators (linacs) with energies above 10 MV radiotherapy treatments RT and IMRT, can improve the distribution of the absorbed dose in the treated area, increasing the effectiveness of radiation treatments. However and as shown in the scientific literature, the production of photoneutrons for energies above 10 MeV can contribute to exposure of both patient and occupationally exposed workers and the public in the vicinity of the installation. It is therefore necessary to determine the value of ambient dose equivalent and staff both inside and outside the facilities that house these accelerators, especially for energies of 15 and 18 MV.

  15. Backgrounded but not peripheral

    DEFF Research Database (Denmark)

    Hovmark, Henrik

    2013-01-01

    .e. the schema enters into apparently contradictory constructions of the informants’ local home-base and, possibly, of their identity (cf. Hovmark, 2010). Second, I discuss the status and role of the specific linguistic category in question, i.e. the directional adverbs. On the one hand we claim that the DDAs......In this paper I pay a closer look at the use of the CENTRE-PERIPHERY schema in context. I address two specific issues: first, I show how the CENTRE-PERIPHERY schema, encoded in the DDAs, enters into discourses that conceptualize and characterize a local community as both CENTRE and PERIPHERY, i......; furthermore, the DDAs are backgrounded in discourse. Is it reasonable to claim, rather boldly, that “the informants express their identity in the use of the directional adverb ud ‘out’ etc.”? In the course of this article, however, I suggest that the DDAs in question do contribute to the socio...

  16. OCRWM Backgrounder, January 1987

    International Nuclear Information System (INIS)

    1987-01-01

    The Nuclear Waste Policy Act of 1982 (NWPA) assigns to the US Department of Energy (DOE) responsibility for developing a system to safely and economically transport spent nuclear fuel and high-level radioactive waste from various storage sites to geologic repositories or other facilities that constitute elements of the waste management program. This transportation system will evolve from technologies and capabilities already developed. Shipments of spent fuel to a monitored retrievable storage (MRS) facility could begin as early as 1996 if Congress authorizes its construction. Shipments of spent fuel to a geologic repository are scheduled to begin in 1998. The backgrounder provides an overview of DOE's cask development program. Transportation casks are a major element in the DOE nuclear waste transportation system because they are the primary protection against any potential radiation exposure to the public and transportation workers in the event an accident occurs

  17. Monitored background radiometer

    International Nuclear Information System (INIS)

    Ruel, C.

    1988-01-01

    A monitored background radiometer is described comprising: a thermally conductive housing; low conductivity support means mounted on the housing; a sensing plate mounted on the low conductivity support means and spaced from the housing so as to be thermally insulated from the housing and having an outwardly facing first surface; the sensing plate being disposed relative to the housing to receive direct electromagnetic radiation from sources exterior to the radiometer upon the first surface only; means for controllably heating the sensing plate; first temperature sensitive means to measure the temperature of the housing; and second temperature sensitive means to measure the temperature of the sensing plate, so that the heat flux at the sensing plate may be determined from the temperatures of the housing and sensing plate after calibration of the radiometer by measuring the temperatures of the housing and sensing plate while controllably heating the sensing plate

  18. Low background infrared (LBIR) facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Low background infrared (LBIR) facility was originally designed to calibrate user supplied blackbody sources and to characterize low-background IR detectors and...

  19. Hanford Site background: Part 1, Soil background for nonradioactive analytes

    International Nuclear Information System (INIS)

    1993-04-01

    Volume two contains the following appendices: Description of soil sampling sites; sampling narrative; raw data soil background; background data analysis; sitewide background soil sampling plan; and use of soil background data for the detection of contamination at waste management unit on the Hanford Site

  20. Note on bouncing backgrounds

    Science.gov (United States)

    de Haro, Jaume; Pan, Supriya

    2018-05-01

    The theory of inflation is one of the fundamental and revolutionary developments of modern cosmology that became able to explain many issues of the early Universe in the context of the standard cosmological model (SCM). However, the initial singularity of the Universe, where physics is indefinite, is still obscure in the combined SCM +inflation scenario. An alternative to SCM +inflation without the initial singularity is thus always welcome, and bouncing cosmology is an attempt at that. The current work is thus motivated to investigate the bouncing solutions in modified gravity theories when the background universe is described by the spatially flat Friedmann-Lemaître-Robertson-Walker (FLRW) geometry. We show that the simplest way to obtain the bouncing cosmologies in such spacetime is to consider some kind of Lagrangian whose gravitational sector depends only on the square of the Hubble parameter of the FLRW universe. For these modified Lagrangians, the corresponding Friedmann equation, a constraint in the dynamics of the Universe, depicts a curve in the phase space (H ,ρ ), where H is the Hubble parameter and ρ is the energy density of the Universe. As a consequence, a bouncing cosmology is obtained when this curve is closed and crosses the axis H =0 at least twice, and whose simplest particular example is the ellipse depicting the well-known holonomy corrected Friedmann equation in loop quantum cosmology (LQC). Sometimes, a crucial point in such theories is the appearance of the Ostrogradski instability at the perturbative level; however, fortunately enough, in the present work, as long as the linear level of perturbations is concerned, this instability does not appear, although it may appear at the higher order of perturbations.

  1. Executive Summary - Historical background

    International Nuclear Information System (INIS)

    2005-01-01

    matter physics experiments at the High Flux Reactor of The Laue Langevin Institute and the ISIS spallation source at Rutherford-Appleton. Recently, we very actively entered the ICARUS neutrino collaboration and were invited to the PIERRE AUGER collaboration which will search for the highest energies in the Universe. Having close ties with CERN we are very actively engaged in CROSS-GRID, a large computer network project. To better understand the historical background of the INP development, it is necessary to add a few comments on financing of science in Poland. During the 70's and the 80's, research was financed through the so-called Central Research Projects for Science and Technical Development. The advantage of this system was that state-allocated research funds were divided only by a few representatives of the scientific community, which allowed realistic allocation of money to a small number of projects. After 1989 we were able to purchase commercially available equipment, which led to the closure of our large and very experienced electronic workshop. We also considerably reduced our well equipped mechanical shop. During the 90's the reduced state financing of science was accompanied by a newly established Committee of Scientific Research which led to the creation of a system of small research projects. This precluded the development of more ambitious research projects and led to the dispersion of equipment among many smaller laboratories and universities. A large research establishment, such as our Institute, could not develop properly under such conditions. In all, between 1989 and 2004 we reduced our personnel from about 800 to 470 and our infrastructure became seriously undercapitalised. However, with energetic search for research funds, from European rather than national research programs, we hope to improve and modernize our laboratories and their infrastructure in the coming years

  2. Background noise levels in Europe

    OpenAIRE

    Gjestland, Truls

    2008-01-01

    - This report gives a brief overview of typical background noise levels in Europe, and suggests a procedure for the prediction of background noise levels based on population density. A proposal for the production of background noise maps for Europe is included.

  3. Backgrounder

    International Development Research Centre (IDRC) Digital Library (Canada)

    IDRC CRDI

    Center for Mountain Ecosystem Studies, Kunming Institute of Botany of the Chinese Academy of Sciences, China: $1,526,000 to inform effective water governance in the Asian highlands of China, Nepal, and Pakistan. • Ashoka Trust for Research in Ecology and the Environment (ATREE), India: $1,499,300 for research on ...

  4. BACKGROUNDER

    International Development Research Centre (IDRC) Digital Library (Canada)

    IDRC CRDI

    demographic trends, socio-economic development pathways, and strong ... knowledge and experience, and encourage innovation. ... choices, and will work with stakeholders in government, business, civil society, and regional economic.

  5. Backgrounder

    International Development Research Centre (IDRC) Digital Library (Canada)

    IDRC CRDI

    Safe and Inclusive Cities: ... improving urban environments and public spaces might have on reducing the city's high ... violence against women among urban youth of working class neighbourhoods of Islamabad, Rawalpindi, and Karachi,.

  6. BACKGROUNDER

    International Development Research Centre (IDRC) Digital Library (Canada)

    IDRC CRDI

    CARIAA's research agenda addresses gaps and priorities highlighted in the ... Research focuses on climate risk, institutional and regulatory frameworks, markets, and ... The researchers will identify relevant drivers and trends and use develop ...

  7. BACKGROUNDER

    International Development Research Centre (IDRC) Digital Library (Canada)

    Corey Piccioni

    achieving long‐term food security in Africa, with a focus on post‐harvest loss, ... nutrion and health, and the socio‐economic factors that affect food supply ... Water use. Agricultural producvity in sub‐Saharan Africa is the lowest in the world.

  8. Psychologické aspekty mezinárodní migrace a integrace cizinců do majoritní společnosti

    OpenAIRE

    Kušniráková, Tereza

    2008-01-01

    8 ABSTRACT__________________________ _______________________________ "Psychological Aspects of International Migration and Integration of Foreigners to Majority Society" This thesis deals with psychological aspects of international migration and psychological background of adaptation to the new environment. The thesis combines general psychology, individual psychology, cross-cultural psychology and behavioral geography. The author applies knowledge of psychology disciplines to the research of...

  9. Diffuse Cosmic Infrared Background Radiation

    Science.gov (United States)

    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.

  10. Background current of radioisotope manometer

    International Nuclear Information System (INIS)

    Vydrik, A.A.

    1987-01-01

    The technique for calculating the main component of the background current of radioisotopic monometers, current from direct collision of ionizing particles and a collector, is described. The reasons for appearance of background photoelectron current are clarified. The most effective way of eliminating background current components is collector protection from the source by a screen made of material with a high gamma-quanta absorption coefficient, such as lead, for example

  11. Background subtraction theory and practice

    CERN Document Server

    Elgammal, Ahmed

    2014-01-01

    Background subtraction is a widely used concept for detection of moving objects in videos. In the last two decades there has been a lot of development in designing algorithms for background subtraction, as well as wide use of these algorithms in various important applications, such as visual surveillance, sports video analysis, motion capture, etc. Various statistical approaches have been proposed to model scene backgrounds. The concept of background subtraction also has been extended to detect objects from videos captured from moving cameras. This book reviews the concept and practice of back

  12. Hanford Site background: Part 1, Soil background for nonradioactive analytes

    International Nuclear Information System (INIS)

    1993-04-01

    The determination of soil background is one of the most important activities supporting environmental restoration and waste management on the Hanford Site. Background compositions serve as the basis for identifying soil contamination, and also as a baseline in risk assessment processes used to determine soil cleanup and treatment levels. These uses of soil background require an understanding of the extent to which analytes of concern occur naturally in the soils. This report documents the results of sampling and analysis activities designed to characterize the composition of soil background at the Hanford Site, and to evaluate the feasibility for use as Sitewide background. The compositions of naturally occurring soils in the vadose Zone have been-determined for-nonradioactive inorganic and organic analytes and related physical properties. These results confirm that a Sitewide approach to the characterization of soil background is technically sound and is a viable alternative to the determination and use of numerous local or area backgrounds that yield inconsistent definitions of contamination. Sitewide soil background consists of several types of data and is appropriate for use in identifying contamination in all soils in the vadose zone on the Hanford Site. The natural concentrations of nearly every inorganic analyte extend to levels that exceed calculated health-based cleanup limits. The levels of most inorganic analytes, however, are well below these health-based limits. The highest measured background concentrations occur in three volumetrically minor soil types, the most important of which are topsoils adjacent to the Columbia River that are rich in organic carbon. No organic analyte levels above detection were found in any of the soil samples

  13. Backgrounds and characteristics of arsonists

    NARCIS (Netherlands)

    Labree, W.; Nijman, H.L.I.; Marle, H.J.C. van; Rassin, E.

    2010-01-01

    The aim of this study was to gain more insight in the backgrounds and characteristics of arsonists. For this, the psychiatric, psychological, personal, and criminal backgrounds of all arsonists (n = 25), sentenced to forced treatment in the maximum security forensic hospital “De Kijvelanden”, were

  14. Measurement of natural background neutron

    CERN Document Server

    Li Jain, Ping; Tang Jin Hua; Tang, E S; Xie Yan Fong

    1982-01-01

    A high sensitive neutron monitor is described. It has an approximate counting rate of 20 cpm for natural background neutrons. The pulse amplitude resolution, sensitivity and direction dependence of the monitor were determined. This monitor has been used for natural background measurement in Beijing area. The yearly average dose is given and compared with the results of KEK and CERN.

  15. Aluminum as a source of background in low background experiments

    Energy Technology Data Exchange (ETDEWEB)

    Majorovits, B., E-mail: bela@mppmu.mpg.de [MPI fuer Physik, Foehringer Ring 6, 80805 Munich (Germany); Abt, I. [MPI fuer Physik, Foehringer Ring 6, 80805 Munich (Germany); Laubenstein, M. [Laboratori Nazionali del Gran Sasso, INFN, S.S.17/bis, km 18 plus 910, I-67100 Assergi (Italy); Volynets, O. [MPI fuer Physik, Foehringer Ring 6, 80805 Munich (Germany)

    2011-08-11

    Neutrinoless double beta decay would be a key to understanding the nature of neutrino masses. The next generation of High Purity Germanium experiments will have to be operated with a background rate of better than 10{sup -5} counts/(kg y keV) in the region of interest around the Q-value of the decay. Therefore, so far irrelevant sources of background have to be considered. The metalization of the surface of germanium detectors is in general done with aluminum. The background from the decays of {sup 22}Na, {sup 26}Al, {sup 226}Ra and {sup 228}Th introduced by this metalization is discussed. It is shown that only a special selection of aluminum can keep these background contributions acceptable.

  16. JEM-X background models

    DEFF Research Database (Denmark)

    Huovelin, J.; Maisala, S.; Schultz, J.

    2003-01-01

    Background and determination of its components for the JEM-X X-ray telescope on INTEGRAL are discussed. A part of the first background observations by JEM-X are analysed and results are compared to predictions. The observations are based on extensive imaging of background near the Crab Nebula...... on revolution 41 of INTEGRAL. Total observing time used for the analysis was 216 502 s, with the average of 25 cps of background for each of the two JEM-X telescopes. JEM-X1 showed slightly higher average background intensity than JEM-X2. The detectors were stable during the long exposures, and weak orbital...... background was enhanced in the central area of a detector, and it decreased radially towards the edge, with a clear vignetting effect for both JEM-X units. The instrument background was weakest in the central area of a detector and showed a steep increase at the very edges of both JEM-X detectors...

  17. Stochastic backgrounds of gravitational waves

    International Nuclear Information System (INIS)

    Maggiore, M.

    2001-01-01

    We review the motivations for the search for stochastic backgrounds of gravitational waves and we compare the experimental sensitivities that can be reached in the near future with the existing bounds and with the theoretical predictions. (author)

  18. Berkeley Low Background Counting Facility

    Data.gov (United States)

    Federal Laboratory Consortium — Sensitive low background assay detectors and sample analysis are available for non-destructive direct gamma-ray assay of samples. Neutron activation analysis is also...

  19. Spectral characterization of natural backgrounds

    Science.gov (United States)

    Winkelmann, Max

    2017-10-01

    As the distribution and use of hyperspectral sensors is constantly increasing, the exploitation of spectral features is a threat for camouflaged objects. To improve camouflage materials at first the spectral behavior of backgrounds has to be known to adjust and optimize the spectral reflectance of camouflage materials. In an international effort, the NATO CSO working group SCI-295 "Development of Methods for Measurements and Evaluation of Natural Background EO Signatures" is developing a method how this characterization of backgrounds has to be done. It is obvious that the spectral characterization of a background will be quite an effort. To compare and exchange data internationally the measurements will have to be done in a similar way. To test and further improve this method an international field trial has been performed in Storkow, Germany. In the following we present first impressions and lessons learned from this field campaign and describe the data that has been measured.

  20. Cosmic microwave background, where next?

    CERN Multimedia

    CERN. Geneva

    2009-01-01

    Ground-based, balloon-borne and space-based experiments will observe the Cosmic Microwave Background in greater details to address open questions about the origin and the evolution of the Universe. In particular, detailed observations the polarization pattern of the Cosmic Microwave Background radiation have the potential to directly probe physics at the GUT scale and illuminate aspects of the physics of the very early Universe.

  1. Personnel hazards from medical electron accelerator photoneutrons

    International Nuclear Information System (INIS)

    McCall, R.C.; Jenkins, T.M.; Shore, R.A.; LaRiviere, P.D.

    1979-12-01

    For medical accelerators, neutron penetration through the room entry door is the major personnel hazard. Most therapy accelerator rooms are designed with at least a rudimentary maze to avoid the use of massive doors. Often, however, the maze may be similar to those shown in scale outline drawings of some medical electron accelerator rooms where the authors have made neutron measurements outside the doors which were of different thicknesses and compositions. The results are tabulated. It should be noted that there can be significant dose equivalents (H) at the door when a maze is inadequate, and that all three components - fast neutron, thermal neutron, and neutron capture γ rays - can be equally important

  2. Looking for Cosmic Neutrino Background

    Directory of Open Access Journals (Sweden)

    Chiaki eYanagisawa

    2014-06-01

    Full Text Available Since the discovery of neutrino oscillation in atmospheric neutrinos by the Super-Kamiokande experiment in 1998, study of neutrinos has been one of exciting fields in high-energy physics. All the mixing angles were measured. Quests for 1 measurements of the remaining parameters, the lightest neutrino mass, the CP violating phase(s, and the sign of mass splitting between the mass eigenstates m3 and m1, and 2 better measurements to determine whether the mixing angle theta23 is less than pi/4, are in progress in a well-controlled manner. Determining the nature of neutrinos, whether they are Dirac or Majorana particles is also in progress with continuous improvement. On the other hand, although the ideas of detecting cosmic neutrino background have been discussed since 1960s, there has not been a serious concerted effort to achieve this goal. One of the reasons is that it is extremely difficult to detect such low energy neutrinos from the Big Bang. While there has been tremendous accumulation of information on Cosmic Microwave Background since its discovery in 1965, there is no direct evidence for Cosmic Neutrino Background. The importance of detecting Cosmic Neutrino Background is that, although detailed studies of Big Bang Nucleosynthesis and Cosmic Microwave Background give information of the early Universe at ~a few minutes old and ~300 k years old, respectively, observation of Cosmic Neutrino Background allows us to study the early Universe at $sim$ 1 sec old. This article reviews progress made in the past 50 years on detection methods of Cosmic Neutrino Background.

  3. Neutron background estimates in GESA

    Directory of Open Access Journals (Sweden)

    Fernandes A.C.

    2014-01-01

    Full Text Available The SIMPLE project looks for nuclear recoil events generated by rare dark matter scattering interactions. Nuclear recoils are also produced by more prevalent cosmogenic neutron interactions. While the rock overburden shields against (μ,n neutrons to below 10−8 cm−2 s−1, it itself contributes via radio-impurities. Additional shielding of these is similar, both suppressing and contributing neutrons. We report on the Monte Carlo (MCNP estimation of the on-detector neutron backgrounds for the SIMPLE experiment located in the GESA facility of the Laboratoire Souterrain à Bas Bruit, and its use in defining additional shielding for measurements which have led to a reduction in the extrinsic neutron background to ∼ 5 × 10−3 evts/kgd. The calculated event rate induced by the neutron background is ∼ 0,3 evts/kgd, with a dominant contribution from the detector container.

  4. LOFT gamma densitometer background fluxes

    International Nuclear Information System (INIS)

    Grimesey, R.A.; McCracken, R.T.

    1978-01-01

    Background gamma-ray fluxes were calculated at the location of the γ densitometers without integral shielding at both the hot-leg and cold-leg primary piping locations. The principal sources for background radiation at the γ densitometers are 16 N activity from the primary piping H 2 O and γ radiation from reactor internal sources. The background radiation was calculated by the point-kernel codes QAD-BSA and QAD-P5A. Reasonable assumptions were required to convert the response functions calculated by point-kernel procedures into the gamma-ray spectrum from reactor internal sources. A brief summary of point-kernel equations and theory is included

  5. A definition of background independence

    International Nuclear Information System (INIS)

    Gryb, Sean

    2010-01-01

    We propose a definition for background (in)/dependence in dynamical theories of the evolution of configurations that have a continuous symmetry and test this definition on particle models and on gravity. Our definition draws from Barbour's best matching framework developed for the purpose of implementing spatial and temporal relationalism. Among other interesting theories, general relativity can be derived within this framework in novel ways. We study the detailed canonical structure of a wide range of best matching theories and show that their actions must have a local gauge symmetry. When gauge theory is derived in this way, we obtain at the same time a conceptual framework for distinguishing between background-dependent and -independent theories. Gauge invariant observables satisfying Kuchar's criterion are identified and, in simple cases, explicitly computed. We propose a procedure for inserting a global background time into temporally relational theories. Interestingly, using this procedure in general relativity leads to unimodular gravity.

  6. Generative electronic background music system

    Energy Technology Data Exchange (ETDEWEB)

    Mazurowski, Lukasz [Faculty of Computer Science, West Pomeranian University of Technology in Szczecin, Zolnierska Street 49, Szczecin, PL (Poland)

    2015-03-10

    In this short paper-extended abstract the new approach to generation of electronic background music has been presented. The Generative Electronic Background Music System (GEBMS) has been located between other related approaches within the musical algorithm positioning framework proposed by Woller et al. The music composition process is performed by a number of mini-models parameterized by further described properties. The mini-models generate fragments of musical patterns used in output composition. Musical pattern and output generation are controlled by container for the mini-models - a host-model. General mechanism has been presented including the example of the synthesized output compositions.

  7. Background metric in supergravity theories

    International Nuclear Information System (INIS)

    Yoneya, T.

    1978-01-01

    In supergravity theories, we investigate the conformal anomaly of the path-integral determinant and the problem of fermion zero modes in the presence of a nontrivial background metric. Except in SO(3) -invariant supergravity, there are nonvanishing conformal anomalies. As a consequence, amplitudes around the nontrivial background metric contain unpredictable arbitrariness. The fermion zero modes which are explicitly constructed for the Euclidean Schwarzschild metric are interpreted as an indication of the supersymmetric multiplet structure of a black hole. The degree of degeneracy of a black hole is 2/sup 4n/ in SO(n) supergravity

  8. Background music and cognitive performance.

    Science.gov (United States)

    Angel, Leslie A; Polzella, Donald J; Elvers, Greg C

    2010-06-01

    The present experiment employed standardized test batteries to assess the effects of fast-tempo music on cognitive performance among 56 male and female university students. A linguistic processing task and a spatial processing task were selected from the Criterion Task Set developed to assess verbal and nonverbal performance. Ten excerpts from Mozart's music matched for tempo were selected. Background music increased the speed of spatial processing and the accuracy of linguistic processing. The findings suggest that background music can have predictable effects on cognitive performance.

  9. Children of ethnic minority backgrounds

    DEFF Research Database (Denmark)

    Johansen, Stine Liv

    2010-01-01

    media products and toys just as they will have knowledge of different media texts, play genres, rhymes etc. This has consequences for their ability to access social settings, for instance in play. New research in this field will focus on how children themselves make sense of this balancing of cultures......Children of ethnic minority background balance their everyday life between a cultural background rooted in their ethnic origin and a daily life in day care, schools and with peers that is founded in a majority culture. This means, among other things, that they often will have access to different...

  10. Generative electronic background music system

    International Nuclear Information System (INIS)

    Mazurowski, Lukasz

    2015-01-01

    In this short paper-extended abstract the new approach to generation of electronic background music has been presented. The Generative Electronic Background Music System (GEBMS) has been located between other related approaches within the musical algorithm positioning framework proposed by Woller et al. The music composition process is performed by a number of mini-models parameterized by further described properties. The mini-models generate fragments of musical patterns used in output composition. Musical pattern and output generation are controlled by container for the mini-models - a host-model. General mechanism has been presented including the example of the synthesized output compositions

  11. Low Background Micromegas in CAST

    DEFF Research Database (Denmark)

    Garza, J G; Aune, S.; Aznar, F.

    2014-01-01

    Solar axions could be converted into x-rays inside the strong magnetic field of an axion helioscope, triggering the detection of this elusive particle. Low background x-ray detectors are an essential component for the sensitivity of these searches. We report on the latest developments of the Micr...

  12. Teaching about Natural Background Radiation

    Science.gov (United States)

    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…

  13. Educational Choice. A Background Paper.

    Science.gov (United States)

    Quality Education for Minorities Network, Washington, DC.

    This paper addresses school choice, one proposal to address parental involvement concerns, focusing on historical background, definitions, rationale for advocating choice, implementation strategies, and implications for minorities and low-income families. In the past, transfer payment programs such as tuition tax credits and vouchers were…

  14. Kerr metric in cosmological background

    Energy Technology Data Exchange (ETDEWEB)

    Vaidya, P C [Gujarat Univ., Ahmedabad (India). Dept. of Mathematics

    1977-06-01

    A metric satisfying Einstein's equation is given which in the vicinity of the source reduces to the well-known Kerr metric and which at large distances reduces to the Robertson-Walker metric of a nomogeneous cosmological model. The radius of the event horizon of the Kerr black hole in the cosmological background is found out.

  15. Low Background Micromegas in CAST

    CERN Document Server

    Garza, J.G.; Aznar, F.; Calvet, D.; Castel, J.F.; Christensen, F.E.; Dafni, T.; Davenport, M.; Decker, T.; Ferrer-Ribas, E.; Galán, J.; García, J.A.; Giomataris, I.; Hill, R.M.; Iguaz, F.J.; Irastorza, I.G.; Jakobsen, A.C.; Jourde, D.; Mirallas, H.; Ortega, I.; Papaevangelou, T.; Pivovaroff, M.J.; Ruz, J.; Tomás, A.; Vafeiadis, T.; Vogel, J.K.

    2015-11-16

    Solar axions could be converted into x-rays inside the strong magnetic field of an axion helioscope, triggering the detection of this elusive particle. Low background x-ray detectors are an essential component for the sensitivity of these searches. We report on the latest developments of the Micromegas detectors for the CERN Axion Solar Telescope (CAST), including technological pathfinder activities for the future International Axion Observatory (IAXO). The use of low background techniques and the application of discrimination algorithms based on the high granularity of the readout have led to background levels below 10$^{-6}$ counts/keV/cm$^2$/s, more than a factor 100 lower than the first generation of Micromegas detectors. The best levels achieved at the Canfranc Underground Laboratory (LSC) are as low as 10$^{-7}$ counts/keV/cm$^2$/s, showing good prospects for the application of this technology in IAXO. The current background model, based on underground and surface measurements, is presented, as well as ...

  16. The Cosmic Infrared Background Experiment

    Science.gov (United States)

    Bock, James; Battle, J.; Cooray, A.; Hristov, V.; Kawada, M.; Keating, B.; Lee, D.; Matsumoto, T.; Matsuura, S.; Nam, U.; Renbarger, T.; Sullivan, I.; Tsumura, K.; Wada, T.; Zemcov, M.

    2009-01-01

    We are developing the Cosmic Infrared Background ExpeRiment (CIBER) to search for signatures of first-light galaxy emission in the extragalactic background. The first generation of stars produce characteristic signatures in the near-infrared extragalactic background, including a redshifted Ly-cutoff feature and a characteristic fluctuation power spectrum, that may be detectable with a specialized instrument. CIBER consists of two wide-field cameras to measure the fluctuation power spectrum, and a low-resolution and a narrow-band spectrometer to measure the absolute background. The cameras will search for fluctuations on angular scales from 7 arcseconds to 2 degrees, where the first-light galaxy spatial power spectrum peaks. The cameras have the necessary combination of sensitivity, wide field of view, spatial resolution, and multiple bands to make a definitive measurement. CIBER will determine if the fluctuations reported by Spitzer arise from first-light galaxies. The cameras observe in a single wide field of view, eliminating systematic errors associated with mosaicing. Two bands are chosen to maximize the first-light signal contrast, at 1.6 um near the expected spectral maximum, and at 1.0 um; the combination is a powerful discriminant against fluctuations arising from local sources. We will observe regions of the sky surveyed by Spitzer and Akari. The low-resolution spectrometer will search for the redshifted Lyman cutoff feature in the 0.7 - 1.8 um spectral region. The narrow-band spectrometer will measure the absolute Zodiacal brightness using the scattered 854.2 nm Ca II Fraunhofer line. The spectrometers will test if reports of a diffuse extragalactic background in the 1 - 2 um band continues into the optical, or is caused by an under estimation of the Zodiacal foreground. We report performance of the assembled and tested instrument as we prepare for a first sounding rocket flight in early 2009. CIBER is funded by the NASA/APRA sub-orbital program.

  17. Background radioactivity in environmental materials

    International Nuclear Information System (INIS)

    Maul, P.R.; O'Hara, J.P.

    1989-01-01

    This paper presents the results of a literature search to identify information on concentrations of 'background' radioactivity in foodstuffs and other commonly available environmental materials. The review has concentrated on naturally occurring radioactivity in foods and on UK data, although results from other countries have also been considered where appropriate. The data are compared with established definitions of a 'radioactive' substance and radionuclides which do not appear to be adequately covered in the literature are noted. (author)

  18. Background paper on aquaculture research

    OpenAIRE

    Wenblad, Axel; Jokumsen, Alfred; Eskelinen, Unto; Torrissen, Ole

    2013-01-01

    The Board of MISTRA established in 2012 a Working Group (WG) on Aquaculture to provide the Board with background information for its upcoming decision on whether the foundation should invest in aquaculture research. The WG included Senior Advisor Axel Wenblad, Sweden (Chairman), Professor Ole Torrissen, Norway, Senior Advisory Scientist Unto Eskelinen, Finland and Senior Advisory Scientist Alfred Jokumsen, Denmark. The WG performed an investigation of the Swedish aquaculture sector including ...

  19. The isotropic radio background revisited

    Energy Technology Data Exchange (ETDEWEB)

    Fornengo, Nicolao; Regis, Marco [Dipartimento di Fisica Teorica, Università di Torino, via P. Giuria 1, I–10125 Torino (Italy); Lineros, Roberto A. [Instituto de Física Corpuscular – CSIC/U. Valencia, Parc Científic, calle Catedrático José Beltrán, 2, E-46980 Paterna (Spain); Taoso, Marco, E-mail: fornengo@to.infn.it, E-mail: rlineros@ific.uv.es, E-mail: regis@to.infn.it, E-mail: taoso@cea.fr [Institut de Physique Théorique, CEA/Saclay, F-91191 Gif-sur-Yvette Cédex (France)

    2014-04-01

    We present an extensive analysis on the determination of the isotropic radio background. We consider six different radio maps, ranging from 22 MHz to 2.3 GHz and covering a large fraction of the sky. The large scale emission is modeled as a linear combination of an isotropic component plus the Galactic synchrotron radiation and thermal bremsstrahlung. Point-like and extended sources are either masked or accounted for by means of a template. We find a robust estimate of the isotropic radio background, with limited scatter among different Galactic models. The level of the isotropic background lies significantly above the contribution obtained by integrating the number counts of observed extragalactic sources. Since the isotropic component dominates at high latitudes, thus making the profile of the total emission flat, a Galactic origin for such excess appears unlikely. We conclude that, unless a systematic offset is present in the maps, and provided that our current understanding of the Galactic synchrotron emission is reasonable, extragalactic sources well below the current experimental threshold seem to account for the majority of the brightness of the extragalactic radio sky.

  20. The isotropic radio background revisited

    International Nuclear Information System (INIS)

    Fornengo, Nicolao; Regis, Marco; Lineros, Roberto A.; Taoso, Marco

    2014-01-01

    We present an extensive analysis on the determination of the isotropic radio background. We consider six different radio maps, ranging from 22 MHz to 2.3 GHz and covering a large fraction of the sky. The large scale emission is modeled as a linear combination of an isotropic component plus the Galactic synchrotron radiation and thermal bremsstrahlung. Point-like and extended sources are either masked or accounted for by means of a template. We find a robust estimate of the isotropic radio background, with limited scatter among different Galactic models. The level of the isotropic background lies significantly above the contribution obtained by integrating the number counts of observed extragalactic sources. Since the isotropic component dominates at high latitudes, thus making the profile of the total emission flat, a Galactic origin for such excess appears unlikely. We conclude that, unless a systematic offset is present in the maps, and provided that our current understanding of the Galactic synchrotron emission is reasonable, extragalactic sources well below the current experimental threshold seem to account for the majority of the brightness of the extragalactic radio sky

  1. Backgrounds and characteristics of arsonists.

    Science.gov (United States)

    Labree, Wim; Nijman, Henk; van Marle, Hjalmar; Rassin, Eric

    2010-01-01

    The aim of this study was to gain more insight in the backgrounds and characteristics of arsonists. For this, the psychiatric, psychological, personal, and criminal backgrounds of all arsonists (n=25), sentenced to forced treatment in the maximum security forensic hospital "De Kijvelanden", were compared to the characteristics of a control group of patients (n=50), incarcerated at the same institution for other severe crimes. Apart from DSM-IV Axis I and Axis II disorders, family backgrounds, level of education, treatment history, intelligence (WAIS scores), and PCL-R scores were included in the comparisons. Furthermore, the apparent motives for the arson offences were explored. It was found that arsonists had more often received psychiatric treatment, prior to committing their index offence, and had a history of severe alcohol abuse more often in comparison to the controls. The arsonists turned out to be less likely to suffer from a major psychotic disorder. Both groups did not differ significantly on the other variables, among which the PCL-R total scores and factor scores. Exploratory analyses however, did suggest that arsonists may differentiate from non-arsonists on three items of the PCL-R, namely impulsivity (higher scores), superficial charm (lower scores), and juvenile delinquency (lower scores). Although the number of arsonists with a major psychotic disorder was relatively low (28%), delusional thinking of some form was judged to play a role in causing arson crimes in about half of the cases (52%).

  2. Family Background and Educational Choices

    DEFF Research Database (Denmark)

    McIntosh, James; D. Munk, Martin

    enrollments, especially for females. Not only did the educational opportunities for individuals with disadvantaged backgrounds improve absolutely, but their relative position also improved. A similarly dramatic increase in attendance at university for the period 1985-2005 was found for these cohorts when......We examine the participation in secondary and tertiary education of five cohorts of Danish males and females who were aged twenty starting in 1982 and ending in 2002. We find that the large expansion of secondary education in this period was characterized by a phenomenal increase in gymnasium...

  3. Background radiation map of Thailand

    International Nuclear Information System (INIS)

    Angsuwathana, P.; Chotikanatis, P.

    1997-01-01

    The radioelement concentration in the natural environment as well as the radiation exposure to man in day-to-day life is now the most interesting topic. The natural radiation is frequently referred as a standard for comparing additional sources of man-made radiation such as atomic weapon fallout, nuclear power generation, radioactive waste disposal, etc. The Department of Mineral Resources commenced a five-year project of nationwide airborne geophysical survey by awarding to Kenting Earth Sciences International Limited in 1984. The original purpose of survey was to support mineral exploration and geological mapping. Subsequently, the data quantity has been proved to be suitable for natural radiation information. In 1993 the Department of Mineral Resources, with the assistance of IAEA, published a Background Radiation Map of Thailand at the scale of 1:1,000,000 from the existing airborne radiometric digital data. The production of Background Radiation Map of Thailand is the result of data compilation and correction procedure developed over the Canadian Shield. This end product will be used as a base map in environmental application not only for Thailand but also Southeast Asia region. (author)

  4. [Cosmic Microwave Background (CMB) Anisotropies

    Science.gov (United States)

    Silk, Joseph

    1998-01-01

    One of the main areas of research is the theory of cosmic microwave background (CMB) anisotropies and analysis of CMB data. Using the four year COBE data we were able to improve existing constraints on global shear and vorticity. We found that, in the flat case (which allows for greatest anisotropy), (omega/H)0 less than 10(exp -7), where omega is the vorticity and H is the Hubble constant. This is two orders of magnitude lower than the tightest, previous constraint. We have defined a new set of statistics which quantify the amount of non-Gaussianity in small field cosmic microwave background maps. By looking at the distribution of power around rings in Fourier space, and at the correlations between adjacent rings, one can identify non-Gaussian features which are masked by large scale Gaussian fluctuations. This may be particularly useful for identifying unresolved localized sources and line-like discontinuities. Levin and collaborators devised a method to determine the global geometry of the universe through observations of patterns in the hot and cold spots of the CMB. We have derived properties of the peaks (maxima) of the CMB anisotropies expected in flat and open CDM models. We represent results for angular resolutions ranging from 5 arcmin to 20 arcmin (antenna FWHM), scales that are relevant for the MAP and COBRA/SAMBA space missions and the ground-based interferometer. Results related to galaxy formation and evolution are also discussed.

  5. Optical polarization: background and camouflage

    Science.gov (United States)

    Škerlind, Christina; Hallberg, Tomas; Eriksson, Johan; Kariis, Hans; Bergström, David

    2017-10-01

    Polarimetric imaging sensors in the electro-optical region, already military and commercially available in both the visual and infrared, show enhanced capabilities for advanced target detection and recognition. The capabilities arise due to the ability to discriminate between man-made and natural background surfaces using the polarization information of light. In the development of materials for signature management in the visible and infrared wavelength regions, different criteria need to be met to fulfil the requirements for a good camouflage against modern sensors. In conventional camouflage design, the aimed design of the surface properties of an object is to spectrally match or adapt it to a background and thereby minimizing the contrast given by a specific threat sensor. Examples will be shown from measurements of some relevant materials and how they in different ways affect the polarimetric signature. Dimensioning properties relevant in an optical camouflage from a polarimetric perspective, such as degree of polarization, the viewing or incident angle, and amount of diffuse reflection, mainly in the infrared region, will be discussed.

  6. The Cosmic Microwave Background Anisotropy

    Science.gov (United States)

    Bennett, C. L.

    1994-12-01

    The properties of the cosmic microwave background radiation provide unique constraints on the history and evolution of the universe. The first detection of anisotropy of the microwave radiation was reported by the COBE Team in 1992, based on the first year of flight data. The latest analyses of the first two years of COBE data are reviewed in this talk, including the amplitude of the microwave anisotropy as a function of angular scale and the statistical nature of the fluctuations. The two-year results are generally consistent with the earlier first year results, but the additional data allow for a better determination of the key cosmological parameters. In this talk the COBE results are compared with other observational anisotropy results and directions for future cosmic microwave anisotropy observations will be discussed. The National Aeronautics and Space Administration/Goddard Space Flight Center (NASA/GSFC) is responsible for the design, development, and operation of the Cosmic Background Explorer (COBE). Scientific guidance is provided by the COBE Science Working Group.

  7. The Proportional Counter. Some Aspects of Operation; Le compteur proportionnel. Ses caracteristiques de fonctionnement; Proportsional'nyj schetchik. Nekotorye aspekty raboty; El contador proportional. Sus caracteristicas de funcionamiento

    Energy Technology Data Exchange (ETDEWEB)

    Curran, S C [Awre, Aldermaston (United Kingdom)

    1960-06-15

    1. Work on a counter system designed for electron capture studies has shown that the diameter of the anode wire in a high-pressure proportional counter can have an important influence on the energy resolution obtained in measurements of low-energy radiations. In a counter working at a pressure of 12 atmospheres the width of the pulse distribution due to 13.5 keV K-capture radiations could be changed from 65% to 17% by changing the wire diameter from 0.0076 mm to 0.0025 mm. This phenomenon is interpreted as an effect of positive ion space charge in the avalanche. For a given gas gain and primary radiation the density of positive ions in the avalanche increases rapidly with pressure of the filling gas, and when the accompanying electric fields are large enough to affect the last stages of the multiplication process the energy resolution of the counter deteriorates. Decrease in diameter of the anode wire increases the externally applied field in the region where multiplication takes place, thus tending to counteract the effect of space charge. Use of 0.0025 mm anode wires has proved satisfactory in new measurements of L/K capture ratios made with a multiwire counter system working at pressures up to 12 atmospheres. The results obtained for L/K capture ratios of Ge{sup 71} and Kr{sup 79} are 0.115 and 0.112 respectively. The same counting system has also been used in a search for M capture in these two isotopes. The low energy of the M capture radiation, 180 eV in Ge{sup 71} and 260 eV in Kr{sup 79}, and its low intensity relative to that of K capture, makes accurate measurement difficult; but peaks attributable to M capture were observed in pulse spectra of both sources. 2. Low-Background Counting - Recent observations made on a combination of proportional counter and scintillation counters (operating as shields) show that there are some real difficulties in devising a relatively simple system of this kind. The performance is inherently very satisfactory but practical

  8. Low background aspects of GERDA

    International Nuclear Information System (INIS)

    Simgen, Hardy

    2011-01-01

    The GERDA experiment operates bare Germanium diodes enriched in 76 Ge in an environment of pure liquid argon to search for neutrinoless double beta decay. A very low radioactive background is essential for the success of the experiment. We present here the research done in order to remove radio-impurities coming from the liquid argon, the stainless steel cryostat and the front-end electronics. We found that liquid argon can be purified efficiently from 222 Rn. The main source of 222 Rn in GERDA is the cryostat which emanates about 55 mBq. A thin copper shroud in the center of the cryostat was implemented to prevent radon from approaching the diodes. Gamma ray screening of radio-pure components for front-end electronics resulted in the development of a pre-amplifier with a total activity of less than 1 mBq 228 Th.

  9. The cosmic microwave background radiation

    International Nuclear Information System (INIS)

    Wilson, R.W.

    1980-01-01

    The history is described of the discovery of microwave radiation of the cosmic background using the 20-foot horn antenna at the Bell Laboratories back in 1965. Ruby masers with travelling wave were used, featuring the lowest noise in the world. The measurement proceeded on 7 cm. In measuring microwave radiation from the regions outside the Milky Way continuous noise was discovered whose temperature exceeded the calculated contributions of the individual detection system elements by 3 K. A comparison with the theory showed that relict radiation from the Big Bang period was the source of the noise. The discovery was verified by measurements on the 20.1 cm wavelength and by other authors' measurements on 0.5 mm to 74 cm, and by optical measurements of the interstellar molecule spectrum. (Ha)

  10. Polarization of Cosmic Microwave Background

    International Nuclear Information System (INIS)

    Buzzelli, A; Cabella, P; De Gasperis, G; Vittorio, N

    2016-01-01

    In this work we present an extension of the ROMA map-making code for data analysis of Cosmic Microwave Background polarization, with particular attention given to the inflationary polarization B-modes. The new algorithm takes into account a possible cross- correlated noise component among the different detectors of a CMB experiment. We tested the code on the observational data of the BOOMERanG (2003) experiment and we show that we are provided with a better estimate of the power spectra, in particular the error bars of the BB spectrum are smaller up to 20% for low multipoles. We point out the general validity of the new method. A possible future application is the LSPE balloon experiment, devoted to the observation of polarization at large angular scales. (paper)

  11. Delayed Neutrons and Photoneutrons from Fission Products; Neutrons Retardes et Photoneutrons Emis par des Produits de Fission; 0417 0410 041f 0410 0417 0414 042b 0412 0410 042e 0429 0418 0415 041d 0415 0419 0422 0420 041e 041d 042b 0418 0424 041e 0422 041e 041d 0415 0419 0422 0420 041e 041d 042b 041f 0420 041e 0414 0423 041a 0422 041e 0412 0414 0415 041b 0415 041d 0418 042f ; Neutrones Retardados y Fotoneutrones de los Productos de Fision

    Energy Technology Data Exchange (ETDEWEB)

    Amiel, S. [Soreq Nuclear Research Centre, Atomic Energy Commission, Yavne (Israel)

    1965-07-15

    Delayed neutrons: Most studies of the delayed neutrons from fission have involved analysis of the kinetic behaviour of fusion chain- reacting systems, analysis of the gross neutron decay (resolved into six groups with approximate half-lives of 0.2, 0.5, 2, 6, 22 and 55 s) and some measurements of the neutron spectra (the energies extendfrom 0.1 to 1.2 MeV, peaking in the range 0.2 to 0.5 MeV). Rapid separations of fission-produced halogens have indicated seven isotopes (Br{sup 87,88,89,90} and I{sup 137,138,139}). and rare gas analysis has indicated 1.5-s Kr and 6-s Rb as definite delayed neutron precursors. These identified precursors account for some 80% of the total delayed neutron yields. Theoretical predictions of possible precursors point to a few tens of such nuclides to be found mainly in regions just above closed neutron shells. Total neutron yields are observed to increase with mass number and decrease with atomic number of the fissioning nuclide. Yields are nearly independent of the energy of the incident fissioning neutron at energies up to several MeV. In this range observed group yields,-especially of the long-lived precursors, ate in fairly good agreement with fission mass and charge distributions, and calculated neutron emission probabilities. . Further detailed studies of delayed neutron precursors (particularly in the difficult short half-life region) require development of ultra-fast radiochemical separation procedures (or on-line isotope separation) and fast neutron spectroscopy of high resolution and efficiency. Photoneutrons; A knowledge of the intensities and gamma-ray spectra of fission products is of practical importance in reactor technology particularly with respect to gamma heating, shielding and radiation effects. Gamma-rays of energies greater than 2.23 and 1.67 MeV cause emission of photoneutrons from deuterium and beryllium respectively, and are important in the kinetics of heavy water and beryllium-moderated reactors. The rate of

  12. Genderové aspekty produkce znalosti

    Czech Academy of Sciences Publication Activity Database

    Tenglerová, Hana

    2011-01-01

    Roč. 9, č. 9 (2011), s. 6 ISSN 1214-1720 R&D Projects: GA MŠk OK08007 Institutional research plan: CEZ:AV0Z70280505 Keywords : gender equality * science * policy Subject RIV: AO - Sociology, Demography http://www.socioweb.cz/upl/editorial/download/193_SOCIOWEB_09_2011.pdf

  13. Bioetika II - Bioetické aspekty eutanazie

    OpenAIRE

    Růžičková, Eva

    2011-01-01

    Author: Eva Růžičková Title: Bioethics II - Bioethical Aspects of Euthanasia Form: Master Thesis Name of University: Charles University in Prague, Faculty of Pharmacy in Hradec Králové Degree: Pharmacy Aim: The aim of this thesis is to explore as much as possible the issues of euthanasia that is one of the most controversial topics of the modern era. Euthanasia interferes with various aspects of the human life - ethic, moral, legal and religious. However, it is vital to determine what can be ...

  14. EKONOMICKÉ ASPEKTY UDRŽITELNÉHO ROZVOJE

    Directory of Open Access Journals (Sweden)

    František Freiberg

    2013-10-01

    Full Text Available The need for sustainable development increasingly affects the behaviour of the corporate sector. The main influencing factors include an expanding regulatory framework and more stringent environmental protection standards. However, if a better match between the corporate behaviour and the principles of sustainable development is to be achieved, businesses themselves will have to be active in seeking ways of meeting social, environmental and economic objectives. Corporations seeking to exercise sustainable development must make sustainable development a part of their strategic planning. The contribution presents the substance of value oriented strategic planning. Delivering value to shareholders is presented as the primary responsibility of corporation. The contribution specifies some types of real benefits derived from sustainable development activities. The attention is addressed to the benefits in the form of reduced expenses in manufacturing, increased revenues, and reduced risk. It is shown that there are good reasons to support shareholders value not only with regards to shareholders but in respect to other stakeholders. Stakeholders are presented as key drivers of business value. Potential benefits created through collaborative stakeholder relations and main specific competencies required for value creation are outlined. Finally the process of sustainable value creation is presented. The characteristic of the competencies and the process of sustainable value creation follow the conception presented in the book Sustainable Company written by Ch. Laszlo. Methodology of sustainable value creation is demonstrated. Following particular steps of the methodology are described: understanding of current position, prediction of future expectation, setting of sustainable value goals, designing of value creation initiatives, developing of the business case, assuring the value, validation of results and building sustainable value capacity.

  15. Diabeticheskaya neyropatiya: epidemiologicheskie i klinicheskie aspekty

    Directory of Open Access Journals (Sweden)

    Gagik Radikovich Galstyan

    2000-03-01

    Full Text Available Актуальность: Термин "диабетическая нейропатия" (ДН объединяет как поражение центральной нервной системы (крайне редко, так и периферической нервной системы, включающей сенсорные, моторные волокна и автономную нервную систему. Цель исследования: Оценить диагностическую ценность "нейропатических" жалоб пациентов, обращающихся в кабинет "Диабетическая стопа\\ выявить возможное прогностическое значение ДН в плане риска язвенно-некротических поражений стоп и времени их заживления; сформулировать практические рекомендации скрининга ДН и использования его результатов в диабетологической практике. Материалы и методы: Обследовано 182 пациента. У 18 (9.89% имел место СД 1 типа, у 164 - СД 2 типа. У 83 больных обнаружены язвенно-некротические поражения стоп (трофические язвы, абсцессы, незаживающие раны после ампутации пальцев. Оценивалась частота синдромов (дистальная полинейропатия, недостаточность артериального кровотока, суставной, отеки нижних конечностей, радикулярный, болезненные гиперкератозы и их сочетаний, а также информативность жалоб по сравнению с порогом вибрационной чувствительности. Результаты: Результаты исследований показали, что синдром дистальной полинейропатии имел место у 85% больных. Вибрационная чувствительность (ВЧ варьировала от 0 до 7 у.е., но во всех группах больных средняя ВЧ была снижена. Чтобы оценить, насколько надежным диагностическим признаком являются типичные "нейропатические" жалобы больных, сопоставляли наличие и отсутствие этих жалоб ("синдром дистальной полинейропатии" и степень снижения ВЧ. Выводы: Анамнез является необходимым условием в дифференциальной диагностике ДН и проявлениях других состояний. Все больные СД нуждаются в периодическом неврологическом обследовании.

  16. Pravni aspekti gradnje i isporuke broda

    Directory of Open Access Journals (Sweden)

    Zoran Tasić

    2014-12-01

    Full Text Available Autor iznosi neke pravne aspekte gradnje i isporuke broda, osvrćući se pri tome ne samo na neke aspekte hrvatskoga prava, već i na prisustvo engleskoga prava u ugovorima o gradnji broda kako hrvatskih, tako i svjetskih brodogradilišta. Mada se radi o izuzetno složenoj pravnoj problematici, autor nastoji približiti neke od bitnih odredaba ugovora o gradnji broda, temeljna prava i obveze ugovornih strana, posljedice neispunjenja ugovornih obveza, pravne aspekte isporuke broda, ulogu klasifikacijskih društava.

  17. Hermeneutické aspekty Husserlovy fenomenologie

    Czech Academy of Sciences Publication Activity Database

    Ďurďovič, Martin

    2013-01-01

    Roč. 61, č. 2 (2013), s. 207-228 ISSN 0015-1831 Institutional support: RVO:68378025 Keywords : genetic phenomenology * theory of perception * hermeneutics Subject RIV: AA - Philosophy ; Religion http://filcasop.flu.cas.cz/index.php?page=starsi-cisla&rok=2013&cislo=2-2013&obsah=565

  18. Některé aspekty multikulturalizmu

    OpenAIRE

    Janatová, Linda

    2011-01-01

    Diploma thesis "Some aspects of multiculturalism" deals with religious minority living in the Czech Republic, especially with Czech muslim women. The aim of this thesis is to explore the most frequent prejudices that relate to Islam religion. To achieve that, concept of multiculturalism, concept prejudice, theory of prejudice as a grouped norm and the most frequent prejudices of Islam are characterized. The history of Islam, It is also described - its origin in the Czech Republic, beginning o...

  19. Measurement of the low-energy quenching factor in germanium using an Y88/Be photoneutron source

    Energy Technology Data Exchange (ETDEWEB)

    Scholz, B. J.; Chavarria, A. E.; Collar, J. I.; Privitera, P.; Robinson, A. E.

    2016-12-01

    We employ an 88Y/Be photoneutron source to derive the quenching factor for neutron-induced nuclear recoils in germanium, probing recoil energies from a few hundred eVnr to 8.5 keVnr. A comprehensive Monte Carlo simulation of our setup is compared to experimental data employing a Lindhard model with a free electronic energy loss k and an adiabatic correction for sub-keVnr nuclear recoils. The best fit k=0.179±0.001 obtained using a Monte Carlo Markov chain (MCMC) ensemble sampler is in good agreement with previous measurements, confirming the adequacy of the Lindhard model to describe the stopping of few-keV ions in germanium crystals at a temperature of ~77 K. This value of k corresponds to a quenching factor of 13.7% to 25.3% for nuclear recoil energies between 0.3 and 8.5 keVnr, respectively.

  20. Plenoptic background oriented schlieren imaging

    International Nuclear Information System (INIS)

    Klemkowsky, Jenna N; Fahringer, Timothy W; Clifford, Christopher J; Thurow, Brian S; Bathel, Brett F

    2017-01-01

    The combination of the background oriented schlieren (BOS) technique with the unique imaging capabilities of a plenoptic camera, termed plenoptic BOS, is introduced as a new addition to the family of schlieren techniques. Compared to conventional single camera BOS, plenoptic BOS is capable of sampling multiple lines-of-sight simultaneously. Displacements from each line-of-sight are collectively used to build a four-dimensional displacement field, which is a vector function structured similarly to the original light field captured in a raw plenoptic image. The displacement field is used to render focused BOS images, which qualitatively are narrow depth of field slices of the density gradient field. Unlike focused schlieren methods that require manually changing the focal plane during data collection, plenoptic BOS synthetically changes the focal plane position during post-processing, such that all focal planes are captured in a single snapshot. Through two different experiments, this work demonstrates that plenoptic BOS is capable of isolating narrow depth of field features, qualitatively inferring depth, and quantitatively estimating the location of disturbances in 3D space. Such results motivate future work to transition this single-camera technique towards quantitative reconstructions of 3D density fields. (paper)

  1. Concerning background from calorimeter ports

    International Nuclear Information System (INIS)

    Digiacomo, N.J.

    1985-01-01

    Any detector system viewing a port or slit in a calorimeter wall will see, in addition to the primary particles of interest, a background of charged and neutral particles and photons generated by scattering from the port walls and by leakage from incompletely contained primary particle showers in the calorimeter near the port. The signal to noise ratio attainable outside the port is a complex function of the primary source spectrum, the calorimeter and port design and, of course, the nature and acceptance of the detector system that views the port. Rather than making general statements about the overall suitability (or lack thereof) of calorimeter ports, we offer here a specific example based on the external spectrometer and slit of the NA34 experiment. This combination of slit and spectrometer is designed for fixed-target work, so that the primary particle momentum spectrum contains higher momentum particles than expected in a heavy ion colliding beam environment. The results are, nevertheless, quite relevant for the collider case

  2. Natural background radiation in Jordan

    International Nuclear Information System (INIS)

    Daoud, M.N.S.

    1997-01-01

    An Airborne Gamma Ray survey has been accomplished for Jordan since 1979. A complete report has been submitted to the Natural Resources Authority along with field and processed data ''digital and analogue''. Natural radioelements concentration is not provided with this report. From the corrected count rate data for each natural radioelement, Concentrations and exposure rates at the ground level were calculated. Contoured maps, showing the exposure rates and the dose rates were created. Both maps reflect the surface geology of Jordan, where the Phosphate areas are very well delineated by high-level contours. In southeastern Jordan the Ordovician sandstone, which contain high percentage of Th (around 2000 ppm in some places) and a moderate percentage of U (about 300 ppm), also show high gamma radiation exposures compared with the surrounding areas. Comparing the values of the exposure rates given in (μR/h) to those obtained from other countries such as United States, Canada, Germany, etc. Jordan shows higher background radiation which reach two folds and even more than those in these countries. More detailed studies should be performed in order to evaluate the radiological risk limits on people who are living in areas of high radiation such that the area of the phosphatic belt which covers a vast area of Jordan high Plateau. (author)

  3. Natural background radiation in Jordan

    Energy Technology Data Exchange (ETDEWEB)

    Daoud, M N.S. [National Resources Authority, Ministry of Energy and Mineral Resources, Amman (Jordan)

    1997-11-01

    An Airborne Gamma Ray survey has been accomplished for Jordan since 1979. A complete report has been submitted to the Natural Resources Authority along with field and processed data ``digital and analogue``. Natural radioelements concentration is not provided with this report. From the corrected count rate data for each natural radioelement, Concentrations and exposure rates at the ground level were calculated. Contoured maps, showing the exposure rates and the dose rates were created. Both maps reflect the surface geology of Jordan, where the Phosphate areas are very well delineated by high-level contours. In southeastern Jordan the Ordovician sandstone, which contain high percentage of Th (around 2000 ppm in some places) and a moderate percentage of U (about 300 ppm), also show high gamma radiation exposures compared with the surrounding areas. Comparing the values of the exposure rates given in ({mu}R/h) to those obtained from other countries such as United States, Canada, Germany, etc. Jordan shows higher background radiation which reach two folds and even more than those in these countries. More detailed studies should be performed in order to evaluate the radiological risk limits on people who are living in areas of high radiation such that the area of the phosphatic belt which covers a vast area of Jordan high Plateau. (author). 8 refs, 10 figs, 7 tabs.

  4. Scientific background of the project

    International Nuclear Information System (INIS)

    Christofidis, I.

    1997-01-01

    The main objective of the proposed project is the development of radioimmunometric assay(s) for the determination of free and total PSA in serum samples from normal and pathological individuals (BPH, PCa). This will be achieved by: A. Selection of appropriate antibody pairs (capture and labelled antibody) for determination of total PSA (free and complex) and for determination of free PSA. From bibliography we have already spotted some antibody pairs. B. Radiolabelling of antibodies. Several labelling and purification procedures will be followed in order to obtain the required analytical sensitivity and dynamic range of the assays. Special attention will be given to the affinity constant as well as to the stability of the radiolabelled molecules. C. Development of protocols for immobilisation of capture antibodies. We will use several solid support formats (plastic tubes, beads and magnetizable particles). Direct adsorption or covalent binding will be used. Immunoadsorption through immobilised second antibody will be also tested in order to decrease the preparation cost of the solid phase reagents. D. Preparation of standards of suitable purity levels. We will test different PSA-free matrices (Bovine serum, buffer solutions etc.) in order to select the most appropriate among them in terms of low background determination and low reagents cost. E. Optimisation of the immunoassays conditions for the free PSA and total PSA (e.g. assay buffers, incubation time, temperature, one or two step procedure, washings). F. Optimisation and standardisation of assay protocols for kit production. G. Production of kits for distribution in clinical laboratories in Greece for comparison with commercial kits. H. Evaluation of the developed assays in real clinical conditions using well characterised human serum samples. This will be performed in co-operation with the Hellenic Society for Tumor Markers, and other anticancer institutions and hospital clinicians of long standing relation

  5. Photoneutron cross sections measurements in {sup 9}Be, {sup 13}C e {sup 17}O with thermal neutron capture gamma-rays; Medidas das secoes de choque de fotoneutrons do {sup 9}Be, {sup 13}C e {sup 17}O com radiacao gama de captura de neutrons termicos

    Energy Technology Data Exchange (ETDEWEB)

    Semmler, Renato

    2006-07-01

    Photoneutron cross sections measurements of {sup 9}Be, {sup 13}C and {sup 17}O have been obtained in the energy interval between 1,6 and 10,8 MeV, using neutron capture gamma-rays with high resolution in energy (3 a 21 eV), produced by 21 target materials, placed inside a tangential beam port, near the core of the IPEN/CNEN-SP IEA-R1 (5 MW) research reactor. The samples have been irradiated inside a 4{pi} geometry neutron detector system 'Long Counter', 520,5 cm away from the capture target. The capture gamma-ray flux was determined by means of the analysis of the gamma spectrum obtained by using a Ge(Li) solid-state detector (EG and G ORTEC, 25 cm{sup 3}, 5%), previously calibrated with capture gamma-rays from a standard target of Nitrogen (Melamine). The neutron photoproduction cross section has been measured for each target capture gamma-ray spectrum (compound cross section). A inversion matrix methodology to solve inversion problems for unfolding the set of experimental compound cross sections, was used in order to obtain the cross sections at specific excitation energy values (principal gamma line energies of the capture targets). The cross sections obtained at the energy values of the principal gamma lines were compared with experimental data reported by other authors, with have employed different gamma-ray sources. A good agreement was observed among the experimental data in this work with reported in the literature. (author)

  6. Simulation of Experimental Background using FLUKA

    Energy Technology Data Exchange (ETDEWEB)

    Rokni, Sayed

    1999-05-11

    In November 1997, Experiment T423 began acquiring data with the intentions of understanding the energy spectra of high-energy neutrons generated in the interaction of electrons with lead. The following describes a series of FLUKA simulations studying (1) particle yields in the absence of all background; (2) the background caused from scattering in the room; (3) the effects of the thick lead shielding which surrounded the detector; (4) the sources of neutron background created in this lead shielding; and (5) the ratio of the total background to the ideal yield. In each case, particular attention is paid to the neutron yield.

  7. Modeling the Thermal Signature of Natural Backgrounds

    National Research Council Canada - National Science Library

    Gamborg, Marius

    2002-01-01

    Two measuring stations have been established the purpose being to collect comprehensive databases of thermal signatures of background elements in addition to the prevailing meteorological conditions...

  8. A statistical background noise correction sensitive to the steadiness of background noise.

    Science.gov (United States)

    Oppenheimer, Charles H

    2016-10-01

    A statistical background noise correction is developed for removing background noise contributions from measured source levels, producing a background noise-corrected source level. Like the standard background noise corrections of ISO 3741, ISO 3744, ISO 3745, and ISO 11201, the statistical background correction increases as the background level approaches the measured source level, decreasing the background noise-corrected source level. Unlike the standard corrections, the statistical background correction increases with steadiness of the background and is excluded from use when background fluctuation could be responsible for measured differences between the source and background noise levels. The statistical background noise correction has several advantages over the standard correction: (1) enveloping the true source with known confidence, (2) assuring physical source descriptions when measuring sources in fluctuating backgrounds, (3) reducing background corrected source descriptions by 1 to 8 dB for sources in steady backgrounds, and (4) providing a means to replace standardized background correction caps that incentivize against high precision grade methods.

  9. Hanford Site background: Part 1, Soil background for nonradioactive analytes. Revision 1, Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    1993-04-01

    Volume two contains the following appendices: Description of soil sampling sites; sampling narrative; raw data soil background; background data analysis; sitewide background soil sampling plan; and use of soil background data for the detection of contamination at waste management unit on the Hanford Site.

  10. 41 CFR 128-1.8001 - Background.

    Science.gov (United States)

    2010-07-01

    ... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Background. 128-1.8001 Section 128-1.8001 Public Contracts and Property Management Federal Property Management Regulations System (Continued) DEPARTMENT OF JUSTICE 1-INTRODUCTION 1.80-Seismic Safety Program § 128-1.8001 Background. The...

  11. Introduction to the background field method

    International Nuclear Information System (INIS)

    Abbott, L.F.; Brandeis Univ., Waltham, MA

    1982-01-01

    The background field approach to calculations in gauge field theories is presented. Conventional functional techniques are reviewed and the background field method is introduced. Feynman rules and renormalization are discussed and, as an example, the Yang-Mills β function is computed. (author)

  12. 12 CFR 408.1 - Background.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 4 2010-01-01 2010-01-01 false Background. 408.1 Section 408.1 Banks and Banking EXPORT-IMPORT BANK OF THE UNITED STATES PROCEDURES FOR COMPLIANCE WITH THE NATIONAL ENVIRONMENTAL POLICY ACT General § 408.1 Background. (a) The National Environmental Policy Act (NEPA) of 1969 (42 U.S.C...

  13. Observing a Gravitational Wave Background With Lisa

    National Research Council Canada - National Science Library

    Tinto, M; Armstrong, J; Estabrook, F

    2000-01-01

    .... Comparison of the conventional Michelson interferometer observable with the fully-symmetric Sagnac data-type allows unambiguous discrimination between a gravitational wave background and instrumental noise. The method presented here can be used to detect a confusion-limited gravitational wave background.

  14. 28 CFR 23.2 - Background.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Background. 23.2 Section 23.2 Judicial Administration DEPARTMENT OF JUSTICE CRIMINAL INTELLIGENCE SYSTEMS OPERATING POLICIES § 23.2 Background. It is... potential threats to the privacy of individuals to whom such data relates, policy guidelines for Federally...

  15. 16 CFR 1404.2 - Background.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Background. 1404.2 Section 1404.2 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS CELLULOSE INSULATION § 1404.2 Background. Based on available fire incident information, engineering analysis of the probable...

  16. Beam-gas Background Observations at LHC

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00214737; The ATLAS collaboration; Alici, Andrea; Lazic, Dragoslav-Laza; Alemany Fernandez, Reyes; Alessio, Federico; Bregliozzi, Giuseppe; Burkhardt, Helmut; Corti, Gloria; Guthoff, Moritz; Manousos, Athanasios; Sjoebaek, Kyrre; D'Auria, Saverio

    2017-01-01

    Observations of beam-induced background at LHC during 2015 and 2016 are presented in this paper. The four LHC experiments use the non-colliding bunches present in the physics-filling pattern of the accelerator to trigger on beam-gas interactions. During luminosity production the LHC experiments record the beam-gas interactions using dedicated background monitors. These data are sent to the LHC control system and are used to monitor the background levels at the experiments during accelerator operation. This is a very important measurement, since poor beam-induced background conditions can seriously affect the performance of the detectors. A summary of the evolution of the background levels during 2015 and 2016 is given in these proceedings.

  17. PENGARUH BACKGROUND MAHASISWA TERHADAP KINERJA AKADEMIK

    Directory of Open Access Journals (Sweden)

    Trianasari Angkawijaya

    2014-09-01

    Full Text Available Abstract: The Effect of Students’ Background on Academic Performance. This study examines the effect of background variables on the academic performance of accounting students in a private university in Surabaya. The background variables under study included previous academic performance, prior knowledge on accounting, sex, motivation, preparedness, and expectations. The results show that previous academic performance, motivation, and expectations have positive and significant effects on the students’ overall academic performance in accounting, while preparedness affects only the students’ performance in management accounting. In contrast, prior knowledge on accounting and sex do not give significant impacts to the students’ overall academic performance.These findings indicate the importance of previous aca­demic performance as well as motivation and expectations as background variables in current academic performance. Keywords: students’ background, academic performance, accounting Abstrak: Pengaruh Background Mahasiswa terhadap Kinerja Akademik. Penelitian ini mengkaji pengaruh variabel background terhadap kinerja akademik mahasiswa akuntansi di Universitas Surabaya. Lima variabel background utama dipergunakan, yaitu kinerja akademik sebelumnya, pengetahuan akun­tansi sebelumnya, jenis kelamin, motivasi, kesiapan, dan ekspektasi. Hipotesis diuji menggunakan model regresi linier berganda OLS dan Robust Standar Error. Hasil penelitian memerlihatkan bahwa kinerja akademik sebelumnya, motivasi, dan ekspektasi memiliki pengaruh positif signifikan terhadap kinerja akademik keseluruhan, sementara kesiapan memberikan pengaruh positif hanya pada kinerja akademik akuntansi manajemen. Sebaliknya, pengetahuan akuntansi sebelumnya dan jenis kelamin tidak memberi­kan pengaruh signifikan terhadap kinerja akademik keseluruhan. Temuan ini mengindikasikan bahwa kinerja akademik sebelumnya beserta motivasi dan ekspektasi adalah variabel background

  18. String pair production in non homogeneous backgrounds

    Energy Technology Data Exchange (ETDEWEB)

    Bolognesi, S. [Department of Physics “E. Fermi” University of Pisa, and INFN - Sezione di Pisa,Largo Pontecorvo, 3, Ed. C, 56127 Pisa (Italy); Rabinovici, E. [Racah Institute of Physics, The Hebrew University of Jerusalem,91904 Jerusalem (Israel); Tallarita, G. [Departamento de Ciencias, Facultad de Artes Liberales,Universidad Adolfo Ibáñez, Santiago 7941169 (Chile)

    2016-04-28

    We consider string pair production in non homogeneous electric backgrounds. We study several particular configurations which can be addressed with the Euclidean world-sheet instanton technique, the analogue of the world-line instanton for particles. In the first case the string is suspended between two D-branes in flat space-time, in the second case the string lives in AdS and terminates on one D-brane (this realizes the holographic Schwinger effect). In some regions of parameter space the result is well approximated by the known analytical formulas, either the particle pair production in non-homogeneous background or the string pair production in homogeneous background. In other cases we see effects which are intrinsically stringy and related to the non-homogeneity of the background. The pair production is enhanced already for particles in time dependent electric field backgrounds. The string nature enhances this even further. For spacial varying electrical background fields the string pair production is less suppressed than the rate of particle pair production. We discuss in some detail how the critical field is affected by the non-homogeneity, for both time and space dependent electric field backgrouds. We also comment on what could be an interesting new prediction for the small field limit. The third case we consider is pair production in holographic confining backgrounds with homogeneous and non-homogeneous fields.

  19. String pair production in non homogeneous backgrounds

    International Nuclear Information System (INIS)

    Bolognesi, S.; Rabinovici, E.; Tallarita, G.

    2016-01-01

    We consider string pair production in non homogeneous electric backgrounds. We study several particular configurations which can be addressed with the Euclidean world-sheet instanton technique, the analogue of the world-line instanton for particles. In the first case the string is suspended between two D-branes in flat space-time, in the second case the string lives in AdS and terminates on one D-brane (this realizes the holographic Schwinger effect). In some regions of parameter space the result is well approximated by the known analytical formulas, either the particle pair production in non-homogeneous background or the string pair production in homogeneous background. In other cases we see effects which are intrinsically stringy and related to the non-homogeneity of the background. The pair production is enhanced already for particles in time dependent electric field backgrounds. The string nature enhances this even further. For spacial varying electrical background fields the string pair production is less suppressed than the rate of particle pair production. We discuss in some detail how the critical field is affected by the non-homogeneity, for both time and space dependent electric field backgrouds. We also comment on what could be an interesting new prediction for the small field limit. The third case we consider is pair production in holographic confining backgrounds with homogeneous and non-homogeneous fields.

  20. Slavnov-Taylor constraints for nontrivial backgrounds

    International Nuclear Information System (INIS)

    Binosi, D.; Quadri, A.

    2011-01-01

    We devise an algebraic procedure for the evaluation of Green's functions in SU(N) Yang-Mills theory in the presence of a nontrivial background field. In the ghost-free sector the dependence of the vertex functional on the background is shown to be uniquely determined by the Slavnov-Taylor identities in terms of a certain 1-PI correlator of the covariant derivatives of the ghost and the antighost fields. At nonvanishing background this amplitude is shown to encode the quantum deformations to the tree-level background-quantum splitting. The approach only relies on the functional identities of the model (Slavnov-Taylor identities, b-equation, antighost equation) and thus it is valid beyond perturbation theory, and, in particular, in a lattice implementation of the background field method. As an example of the formalism we analyze the ghost two-point function and the Kugo-Ojima function in an instanton background in SU(2) Yang-Mills theory, quantized in the background Landau gauge.

  1. Sources of the Radio Background Considered

    Energy Technology Data Exchange (ETDEWEB)

    Singal, J.; /KIPAC, Menlo Park /Stanford U.; Stawarz, L.; /KIPAC, Menlo Park /Stanford U. /Jagiellonian U., Astron. Observ.; Lawrence, A.; /Edinburgh U., Inst. Astron. /KIPAC, Menlo Park /Stanford U.; Petrosian, V.; /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., Appl. Phys. Dept.

    2011-08-22

    We investigate possible origins of the extragalactic radio background reported by the ARCADE 2 collaboration. The surface brightness of the background is several times higher than that which would result from currently observed radio sources. We consider contributions to the background from diffuse synchrotron emission from clusters and the intergalactic medium, previously unrecognized flux from low surface brightness regions of radio sources, and faint point sources below the flux limit of existing surveys. By examining radio source counts available in the literature, we conclude that most of the radio background is produced by radio point sources that dominate at sub {mu}Jy fluxes. We show that a truly diffuse background produced by elections far from galaxies is ruled out because such energetic electrons would overproduce the observed X-ray/{gamma}-ray background through inverse Compton scattering of the other photon fields. Unrecognized flux from low surface brightness regions of extended radio sources, or moderate flux sources missed entirely by radio source count surveys, cannot explain the bulk of the observed background, but may contribute as much as 10%. We consider both radio supernovae and radio quiet quasars as candidate sources for the background, and show that both fail to produce it at the observed level because of insufficient number of objects and total flux, although radio quiet quasars contribute at the level of at least a few percent. We conclude that the most important population for production of the background is likely ordinary starforming galaxies above redshift 1 characterized by an evolving radio far-infrared correlation, which increases toward the radio loud with redshift.

  2. Extragalactic background light measurements and applications.

    Science.gov (United States)

    Cooray, Asantha

    2016-03-01

    This review covers the measurements related to the extragalactic background light intensity from γ-rays to radio in the electromagnetic spectrum over 20 decades in wavelength. The cosmic microwave background (CMB) remains the best measured spectrum with an accuracy better than 1%. The measurements related to the cosmic optical background (COB), centred at 1 μm, are impacted by the large zodiacal light associated with interplanetary dust in the inner Solar System. The best measurements of COB come from an indirect technique involving γ-ray spectra of bright blazars with an absorption feature resulting from pair-production off of COB photons. The cosmic infrared background (CIB) peaking at around 100 μm established an energetically important background with an intensity comparable to the optical background. This discovery paved the way for large aperture far-infrared and sub-millimetre observations resulting in the discovery of dusty, starbursting galaxies. Their role in galaxy formation and evolution remains an active area of research in modern-day astrophysics. The extreme UV (EUV) background remains mostly unexplored and will be a challenge to measure due to the high Galactic background and absorption of extragalactic photons by the intergalactic medium at these EUV/soft X-ray energies. We also summarize our understanding of the spatial anisotropies and angular power spectra of intensity fluctuations. We motivate a precise direct measurement of the COB between 0.1 and 5 μm using a small aperture telescope observing either from the outer Solar System, at distances of 5 AU or more, or out of the ecliptic plane. Other future applications include improving our understanding of the background at TeV energies and spectral distortions of CMB and CIB.

  3. Do instantons like a colorful background?

    Energy Technology Data Exchange (ETDEWEB)

    Gies, H.; Pawlowski, J.M.; Wetterich, C. [Heidelberg Univ. (Germany). Inst. fuer Theoretische Physik; Jaeckel, J. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2006-08-15

    We investigate chiral symmetry breaking and color symmetry breaking in QCD. The effective potential of the corresponding scalar condensates is discussed in the presence of non-perturbative contributions from the semiclassical one-instanton sector. We concentrate on a color singlet scalar background which can describe chiral condensation, as well as a color cotet scalar background which can generate mass for the gluons. Whereas a non-vanishing singlet chiral field is favored by the instantons, we have found no indication for a preference of color octet backgrounds. (orig.)

  4. On the microwave background spectrum and noise

    International Nuclear Information System (INIS)

    De Bernardis, P.; Masi, S.

    1982-01-01

    We show that the combined measurement of the cosmic background radiation (CBR) intensity and noise can provide direct information on the temperature and the emissivity of the source responsible for the CBR. (orig.)

  5. Quantum background independence in string theory

    International Nuclear Information System (INIS)

    Witten, E.

    1994-01-01

    Not only in physical string theories, but also in some highly simplified situations, background independence has been difficult to understand. It is argued that the ''holomorphic anomaly'' of Bershadsky, Cecotti, Ooguri and Vafa gives a fundamental explanation of some of the problems. Moreover, their anomaly equation can be interpreted in terms of a rather peculiar quantum version of background independence: in systems afflicted by the anomaly, background independence does not hold order by order in perturbation theory, but the exact partition function as a function of the coupling constants has a background independent interpretation as a state in an auxiliary quantum Hilbert space. The significance of this auxiliary space is otherwise unknown. (author). 23 refs

  6. Background-cross-section-dependent subgroup parameters

    International Nuclear Information System (INIS)

    Yamamoto, Toshihisa

    2003-01-01

    A new set of subgroup parameters was derived that can reproduce the self-shielded cross section against a wide range of background cross sections. The subgroup parameters are expressed with a rational equation which numerator and denominator are expressed as the expansion series of background cross section, so that the background cross section dependence is exactly taken into account in the parameters. The advantage of the new subgroup parameters is that they can reproduce the self-shielded effect not only by group basis but also by subgroup basis. Then an adaptive method is also proposed which uses fitting procedure to evaluate the background-cross-section-dependence of the parameters. One of the simple fitting formula was able to reproduce the self-shielded subgroup cross section by less than 1% error from the precise evaluation. (author)

  7. REQUEST FOR EXPRESSIONS OF INTEREST For Background ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    sbickram

    2012-07-10

    Jul 10, 2012 ... the applicant's qualifications and ability to undertake the hot spot background study. ... any interviews, presentations and subsequent proposals, are the sole ... The program will focus on increasing the resilience of the most ...

  8. Background music: effects on attention performance.

    Science.gov (United States)

    Shih, Yi-Nuo; Huang, Rong-Hwa; Chiang, Hsin-Yu

    2012-01-01

    Previous studies indicate that noise may affect worker attention. However, some background music in the work environment can increase worker satisfaction and productivity. This study compared how music with, and without, lyrics affects human attention. One hundred and two participants, aged 20-24 years, were recruited into this study. Fifty-six males and 46 females participated in this study. Background music with, and without lyrics, was tested for effects on listener concentration in attention testing using a randomized controlled trial (RCT) study. The comparison results revealed that background music with lyrics had significant negative effects on concentration and attention. The findings suggest that, if background music is played in the work environment, music without lyrics is preferable because songs with lyrics are likely to reduce worker attention and performance.

  9. History and background of the project

    Digital Repository Service at National Institute of Oceanography (India)

    Jauhari, P.; Nair, R.R.

    The history of oceanography, the discovery of manganese nodules and the background of the developments in nodule research and mining is given The first nodules were collected in 1981 on board the research vessel R V Gaveshani Following the success...

  10. 47 CFR 215.1 - Background.

    Science.gov (United States)

    2010-10-01

    ... POINT FOR ELECTROMAGNETIC PULSE (EMP) INFORMATION § 215.1 Background. (a) The nuclear electromagnetic pulse (EMP) is part of the complex environment produced by nuclear explosions. It consists of transient...

  11. 32 CFR 770.49 - Background.

    Science.gov (United States)

    2010-07-01

    ..., Washington § 770.49 Background. (a) Puget Sound Naval Shipyard is a major naval ship repair facility, with... interruption. Additionally, most of Puget Sound Naval Shipyard is dedicated to heavy industrial activity where...

  12. Mathematical Background of Public Key Cryptography

    DEFF Research Database (Denmark)

    Frey, Gerhard; Lange, Tanja

    2005-01-01

    The two main systems used for public key cryptography are RSA and protocols based on the discrete logarithm problem in some cyclic group. We focus on the latter problem and state cryptographic protocols and mathematical background material.......The two main systems used for public key cryptography are RSA and protocols based on the discrete logarithm problem in some cyclic group. We focus on the latter problem and state cryptographic protocols and mathematical background material....

  13. A Practical Theorem on Gravitational Wave Backgrounds

    OpenAIRE

    Phinney, E. S.

    2001-01-01

    There is an extremely simple relationship between the spectrum of the gravitational wave background produced by a cosmological distribution of discrete gravitational wave sources, the total time-integrated energy spectrum of an individual source, and the present-day comoving number density of remnants. Stated in this way, the background is entirely independent of the cosmology, and only weakly dependent on the evolutionary history of the sources. This relationship allows one easily to compute...

  14. Isotherms clustering in cosmic microwave background

    International Nuclear Information System (INIS)

    Bershadskii, A.

    2006-01-01

    Isotherms clustering in cosmic microwave background (CMB) has been studied using the 3-year WMAP data on cosmic microwave background radiation. It is shown that the isotherms clustering could be produced by the baryon-photon fluid turbulence in the last scattering surface. The Taylor-microscale Reynolds number of the turbulence is estimated directly from the CMB data as Re λ ∼10 2

  15. Classification of supersymmetric backgrounds of string theory

    International Nuclear Information System (INIS)

    Gran, U.; Gutowski, J.; Papadopoulos, G.; Roest, D.

    2007-01-01

    We review the recent progress made towards the classification of supersymmetric solutions in ten and eleven dimensions with emphasis on those of IIB supergravity. In particular, the spinorial geometry method is outlined and adapted to nearly maximally supersymmetric backgrounds. We then demonstrate its effectiveness by classifying the maximally supersymmetric IIB G-backgrounds and by showing that N=31 IIB solutions do not exist. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  16. Superstring gravitational wave backgrounds with spacetime supersymmetry

    CERN Document Server

    Kiritsis, Elias B; Lüst, Dieter; Kiritsis, E; Kounnas, C; Lüst, D

    1994-01-01

    We analyse the stringy gravitational wave background based on the current algebra E.sup(c).sub(2). We determine its exact spectrum and construct the modular invariant vacuum energy. The corresponding N=1 extension is also constructed. The algebra is again mapped to free bosons and fermions and we show that this background has N=4 (N=2) unbroken spacetime supersymmetry in the type II (heterotic case).

  17. Background dose subtraction in personnel dosimetry

    International Nuclear Information System (INIS)

    Picazo, T.; Llorca, N.; Alabau, J.

    1997-01-01

    In this paper it is proposed to consider the mode of the frequency distribution of the low dose dosemeters from each clinic that uses X rays as the background environmental dose that should be subtracted from the personnel dosimetry to evaluate the doses due to practice. The problems and advantages of this indirect method to estimate the environmental background dose are discussed. The results for 60 towns are presented. (author)

  18. Moving object detection using background subtraction

    CERN Document Server

    Shaikh, Soharab Hossain; Chaki, Nabendu

    2014-01-01

    This Springer Brief presents a comprehensive survey of the existing methodologies of background subtraction methods. It presents a framework for quantitative performance evaluation of different approaches and summarizes the public databases available for research purposes. This well-known methodology has applications in moving object detection from video captured with a stationery camera, separating foreground and background objects and object classification and recognition. The authors identify common challenges faced by researchers including gradual or sudden illumination change, dynamic bac

  19. Aircraft and background noise annoyance effects

    Science.gov (United States)

    Willshire, K. F.

    1984-01-01

    To investigate annoyance of multiple noise sources, two experiments were conducted. The first experiment, which used 48 subjects, was designed to establish annoyance-noise level functions for three community noise sources presented individually: jet aircraft flyovers, air conditioner, and traffic. The second experiment, which used 216 subjects, investigated the effects of background noise on aircraft annoyance as a function of noise level and spectrum shape; and the differences between overall, aircraft, and background noise annoyance. In both experiments, rated annoyance was the dependent measure. Results indicate that the slope of the linear relationship between annoyance and noise level for traffic is significantly different from that of flyover and air conditioner noise and that further research was justified to determine the influence of the two background noises on overall, aircraft, and background noise annoyance (e.g., experiment two). In experiment two, total noise exposure, signal-to-noise ratio, and background source type were found to have effects on all three types of annoyance. Thus, both signal-to-noise ratio, and the background source must be considered when trying to determine community response to combined noise sources.

  20. Low energy background radiation in India

    International Nuclear Information System (INIS)

    Gopinath, D.V.

    1980-01-01

    Spectral distribution of background radiation at 9 locations spread all over India has been measured. Specifications of the counting set-up standardised for measurement are given. At one of the places, the background spectrum was measured with four different types of detectors. A broad peak in 60-100 keV with differing intensity and standard deviation is observed in all the spectra. In the Kalpakkam area, the peak near the seashore is observed to be more intense than away from the shore. This could be due to the presence of monazite sands on the seashore. The natural background radiation is observed to have a steep rise below 20 keV. Peak intensity is found to be independent of both the location (i.e. the source of energy) and the type of detector used for measurement. The calculated spectra due to multiple scattered radiation (with a nominal source energy of 1 MeV) through paraffin wax and the measured background spectrum with the detector shielded with 20 cm wax show good agreement above 40 keV. This shows that 80 keV hump in the natural background radiation is a property of air. The peak, therefore, in the spectra of natural background radiation is essentially a property of medium and it is independent of location or detector. (M.G.B.)

  1. Background of SAM atom-fraction profiles

    International Nuclear Information System (INIS)

    Ernst, Frank

    2017-01-01

    Atom-fraction profiles acquired by SAM (scanning Auger microprobe) have important applications, e.g. in the context of alloy surface engineering by infusion of carbon or nitrogen through the alloy surface. However, such profiles often exhibit an artifact in form of a background with a level that anti-correlates with the local atom fraction. This article presents a theory explaining this phenomenon as a consequence of the way in which random noise in the spectrum propagates into the discretized differentiated spectrum that is used for quantification. The resulting model of “energy channel statistics” leads to a useful semi-quantitative background reduction procedure, which is validated by applying it to simulated data. Subsequently, the procedure is applied to an example of experimental SAM data. The analysis leads to conclusions regarding optimum experimental acquisition conditions. The proposed method of background reduction is based on general principles and should be useful for a broad variety of applications. - Highlights: • Atom-fraction–depth profiles of carbon measured by scanning Auger microprobe • Strong background, varies with local carbon concentration. • Needs correction e.g. for quantitative comparison with simulations • Quantitative theory explains background. • Provides background removal strategy and practical advice for acquisition

  2. Background of SAM atom-fraction profiles

    Energy Technology Data Exchange (ETDEWEB)

    Ernst, Frank

    2017-03-15

    Atom-fraction profiles acquired by SAM (scanning Auger microprobe) have important applications, e.g. in the context of alloy surface engineering by infusion of carbon or nitrogen through the alloy surface. However, such profiles often exhibit an artifact in form of a background with a level that anti-correlates with the local atom fraction. This article presents a theory explaining this phenomenon as a consequence of the way in which random noise in the spectrum propagates into the discretized differentiated spectrum that is used for quantification. The resulting model of “energy channel statistics” leads to a useful semi-quantitative background reduction procedure, which is validated by applying it to simulated data. Subsequently, the procedure is applied to an example of experimental SAM data. The analysis leads to conclusions regarding optimum experimental acquisition conditions. The proposed method of background reduction is based on general principles and should be useful for a broad variety of applications. - Highlights: • Atom-fraction–depth profiles of carbon measured by scanning Auger microprobe • Strong background, varies with local carbon concentration. • Needs correction e.g. for quantitative comparison with simulations • Quantitative theory explains background. • Provides background removal strategy and practical advice for acquisition.

  3. Non-collision backgrounds in ATLAS

    CERN Document Server

    Gibson, S M; The ATLAS collaboration

    2012-01-01

    The proton-proton collision events recorded by the ATLAS experiment are on top of a background that is due to both collision debris and non-collision components. The latter comprises of three types: beam-induced backgrounds, cosmic particles and detector noise. We present studies that focus on the first two of these. We give a detailed description of beam-related and cosmic backgrounds based on the full 2011 ATLAS data set, and present their rates throughout the whole data-taking period. Studies of correlations between tertiary proton halo and muon backgrounds, as well as, residual pressure and resulting beam-gas events seen in beam-condition monitors will be presented. Results of simulations based on the LHC geometry and its parameters will be presented. They help to better understand the features of beam-induced backgrounds in each ATLAS sub-detector. The studies of beam-induced backgrounds in ATLAS reveal their characteristics and serve as a basis for designing rejection tools that can be applied in physic...

  4. Background enhancement in breast MR: Correlation with breast density in mammography and background echotexture in ultrasound

    International Nuclear Information System (INIS)

    Ko, Eun Sook; Lee, Byung Hee; Choi, Hye Young; Kim, Rock Bum; Noh, Woo-Chul

    2011-01-01

    Objective: This study aimed to determine whether background enhancement on MR was related to mammographic breast density or ultrasonographic background echotexture in premenopausal and postmenopausal women. Materials and methods: We studied 142 patients (79 premenopausal, 63 postmenopausal) who underwent mammography, ultrasonography, and breast MR. We reviewed the mammography for overall breast density of the contralateral normal breast according to the four-point scale of the BI-RADS classification. Ultrasound findings were classified as homogeneous or heterogeneous background echotexture according to the BI-RADS lexicon. We rated background enhancement on a contralateral breast MR into four categories based on subtraction images: absent, mild, moderate, and marked. All imaging findings were interpreted independently by two readers without knowledge of menstrual status, imaging findings of other modalities. Results: There were significant differences between the premenopausal and postmenopausal group in distribution of mammographic breast density, ultrasonographic background echotexture, and degree of background enhancement. Regarding the relationship between mammographic density and background enhancement, there was no significant correlation. There was significant relationship between ultrasonographic background echotexture and background enhancement in both premenopausal and postmenopausal groups. Conclusion: There is a significant correlation between ultrasonographic background echotexture and background enhancement in MR regardless of menopausal status. Interpreting breast MR, or scheduling for breast MR of women showing heterogeneous background echotexture needs more caution.

  5. The background in the experiment Gerda

    Science.gov (United States)

    Agostini, M.; Allardt, M.; Andreotti, E.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Barnabé Heider, M.; Barros, N.; Baudis, L.; Bauer, C.; Becerici-Schmidt, N.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Benato, G.; Bettini, A.; Bezrukov, L.; Bode, T.; Brudanin, V.; Brugnera, R.; Budjáš, D.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; Cossavella, F.; Demidova, E. V.; Domula, A.; Egorov, V.; Falkenstein, R.; Ferella, A.; Freund, K.; Frodyma, N.; Gangapshev, A.; Garfagnini, A.; Gotti, C.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Guthikonda, K. K.; Hampel, W.; Hegai, A.; Heisel, M.; Hemmer, S.; Heusser, G.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Ioannucci, L.; Csáthy, J. Janicskó; Jochum, J.; Junker, M.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Klimenko, A.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V. V.; Laubenstein, M.; Lazzaro, A.; Lebedev, V. I.; Lehnert, B.; Liao, H. Y.; Lindner, M.; Lippi, I.; Liu, X.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Macolino, C.; Machado, A. A.; Majorovits, B.; Maneschg, W.; Nemchenok, I.; Nisi, S.; O'Shaughnessy, C.; Palioselitis, D.; Pandola, L.; Pelczar, K.; Pessina, G.; Pullia, A.; Riboldi, S.; Sada, C.; Salathe, M.; Schmitt, C.; Schreiner, J.; Schulz, O.; Schwingenheuer, B.; Schönert, S.; Shevchik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Strecker, H.; Tarka, M.; Ur, C. A.; Vasenko, A. A.; Volynets, O.; von Sturm, K.; Wagner, V.; Walter, M.; Wegmann, A.; Wester, T.; Wojcik, M.; Yanovich, E.; Zavarise, P.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zuber, K.; Zuzel, G.

    2014-04-01

    The GERmanium Detector Array ( Gerda) experiment at the Gran Sasso underground laboratory (LNGS) of INFN is searching for neutrinoless double beta () decay of Ge. The signature of the signal is a monoenergetic peak at 2039 keV, the value of the decay. To avoid bias in the signal search, the present analysis does not consider all those events, that fall in a 40 keV wide region centered around . The main parameters needed for the analysis are described. A background model was developed to describe the observed energy spectrum. The model contains several contributions, that are expected on the basis of material screening or that are established by the observation of characteristic structures in the energy spectrum. The model predicts a flat energy spectrum for the blinding window around with a background index ranging from 17.6 to 23.8 cts/(keV kg yr). A part of the data not considered before has been used to test if the predictions of the background model are consistent. The observed number of events in this energy region is consistent with the background model. The background at is dominated by close sources, mainly due to K, Bi, Th, Co and emitting isotopes from the Ra decay chain. The individual fractions depend on the assumed locations of the contaminants. It is shown, that after removal of the known peaks, the energy spectrum can be fitted in an energy range of 200 keV around with a constant background. This gives a background index consistent with the full model and uncertainties of the same size.

  6. The spinorial geometry of supersymmetric backgrounds

    International Nuclear Information System (INIS)

    Gillard, J; Gran, U; Papadopoulos, G

    2005-01-01

    We propose a new method to solve the Killing spinor equations of 11-dimensional supergravity based on a description of spinors in terms of forms and on the Spin(1, 10) gauge symmetry of the supercovariant derivative. We give the canonical form of Killing spinors for backgrounds preserving two supersymmetries, N = 2, provided that one of the spinors represents the orbit of Spin(1, 10) with stability subgroup SU(5). We directly solve the Killing spinor equations of N = 1 and some N = 2, N = 3 and N = 4 backgrounds. In the N = 2 case, we investigate backgrounds with SU(5) and SU(4) invariant Killing spinors and compute the associated spacetime forms. We find that N = 2 backgrounds with SU(5) invariant Killing spinors admit a timelike Killing vector and that the space transverse to the orbits of this vector field is a Hermitian manifold with an SU(5)-structure. Furthermore, N = 2 backgrounds with SU(4) invariant Killing spinors admit two Killing vectors, one timelike and one spacelike. The space transverse to the orbits of the former is an almost Hermitian manifold with an SU(4)-structure. The spacelike Killing vector field leaves the almost complex structure invariant. We explore the canonical form of Killing spinors for backgrounds preserving more than two supersymmetries, N > 2. We investigate a class of N = 3 and N = 4 backgrounds with SU(4) invariant spinors. We find that in both cases the space transverse to a timelike vector field is a Hermitian manifold equipped with an SU(4)-structure and admits two holomorphic Killing vector fields. We also present an application to M-theory Calabi-Yau compactifications with fluxes to one dimension

  7. The spinorial geometry of supersymmetric backgrounds

    Energy Technology Data Exchange (ETDEWEB)

    Gillard, J; Gran, U; Papadopoulos, G [Department of Mathematics, King' s College London, Strand, London WC2R 2LS (United Kingdom)

    2005-03-21

    We propose a new method to solve the Killing spinor equations of 11-dimensional supergravity based on a description of spinors in terms of forms and on the Spin(1, 10) gauge symmetry of the supercovariant derivative. We give the canonical form of Killing spinors for backgrounds preserving two supersymmetries, N = 2, provided that one of the spinors represents the orbit of Spin(1, 10) with stability subgroup SU(5). We directly solve the Killing spinor equations of N = 1 and some N = 2, N = 3 and N = 4 backgrounds. In the N = 2 case, we investigate backgrounds with SU(5) and SU(4) invariant Killing spinors and compute the associated spacetime forms. We find that N = 2 backgrounds with SU(5) invariant Killing spinors admit a timelike Killing vector and that the space transverse to the orbits of this vector field is a Hermitian manifold with an SU(5)-structure. Furthermore, N = 2 backgrounds with SU(4) invariant Killing spinors admit two Killing vectors, one timelike and one spacelike. The space transverse to the orbits of the former is an almost Hermitian manifold with an SU(4)-structure. The spacelike Killing vector field leaves the almost complex structure invariant. We explore the canonical form of Killing spinors for backgrounds preserving more than two supersymmetries, N > 2. We investigate a class of N = 3 and N = 4 backgrounds with SU(4) invariant spinors. We find that in both cases the space transverse to a timelike vector field is a Hermitian manifold equipped with an SU(4)-structure and admits two holomorphic Killing vector fields. We also present an application to M-theory Calabi-Yau compactifications with fluxes to one dimension.

  8. Ablation plume dynamics in a background gas

    DEFF Research Database (Denmark)

    Amoruso, Salvatore; Schou, Jørgen; Lunney, James G.

    2010-01-01

    The expansion of a plume in a background gas of pressure comparable to that used in pulsed laser deposition (PLD) has been analyzed in terms of the model of Predtechensky and Mayorov (PM). This approach gives a relatively clear and simple description of the essential hydrodynamics during the expa......The expansion of a plume in a background gas of pressure comparable to that used in pulsed laser deposition (PLD) has been analyzed in terms of the model of Predtechensky and Mayorov (PM). This approach gives a relatively clear and simple description of the essential hydrodynamics during...... the expansion. The model also leads to an insightful treatment of the stopping behavior in dimensionless units for plumes and background gases of different atomic/molecular masses. The energetics of the plume dynamics can also be treated with this model. Experimental time-of-flight data of silver ions in a neon...... background gas show a fair agreement with predictions from the PM-model. Finally we discuss the validity of the model, if the work done by the pressure of the background gas is neglected....

  9. Measurements of the cosmic background radiation

    International Nuclear Information System (INIS)

    Weiss, R.

    1980-01-01

    Measurements of the attributes of the 2.7-K microwave background radiation (CBR) are reviewed, with emphasis on the analytic phase of CBR studies. Methods for the direct measurement of the CBR spectrum are discussed. Attention is given to receivers, antennas, absolute receiver calibration, atmospheric emission and absorption, the galactic background contribution, the analysis of LF measurements, and recent HF observations of the CBR spectrum. Measurements of the large-angular-scale intensity distribution of the CBR (the most convincing evidence that the radiation is of cosmological origin) are examined, along with limits on the linear polarization of the CBR. A description is given of the NASA-sponsored Cosmic Background Explorer (COBE) satellite mission. The results of the COBE mission will be a set of sky maps showing, in the wave number range from 1 to 10,000 kaysers, the galactic background radiation due to synchrotron emission from galactic cosmic rays, to diffuse thermal emission from H II regions, and to diffuse thermal emission from interstellar and interplanetary dust, as well as a residue consisting of the CBR and whatever other cosmological background might exist

  10. Monte Carlo simulations of low background detectors

    International Nuclear Information System (INIS)

    Miley, H.S.; Brodzinski, R.L.; Hensley, W.K.; Reeves, J.H.

    1995-01-01

    An implementation of the Electron Gamma Shower 4 code (EGS4) has been developed to allow convenient simulation of typical gamma ray measurement systems. Coincidence gamma rays, beta spectra, and angular correlations have been added to adequately simulate a complete nuclear decay and provide corrections to experimentally determined detector efficiencies. This code has been used to strip certain low-background spectra for the purpose of extremely low-level assay. Monte Carlo calculations of this sort can be extremely successful since low background detectors are usually free of significant contributions from poorly localized radiation sources, such as cosmic muons, secondary cosmic neutrons, and radioactive construction or shielding materials. Previously, validation of this code has been obtained from a series of comparisons between measurements and blind calculations. An example of the application of this code to an exceedingly low background spectrum stripping will be presented. (author) 5 refs.; 3 figs.; 1 tab

  11. Background harmonic superfields in N=2 supergravity

    International Nuclear Information System (INIS)

    Zupnik, B.M.

    1998-01-01

    A modification of the harmonic superfield formalism in D=4, N=2 supergravity using a subsidiary condition of covariance under the background supersymmetry with a central charge (B-covariance) is considered. Conservation of analyticity together with the B-covariance leads to the appearance of linear gravitational superfields. Analytic prepotentials arise in a decomposition of the background linear superfields in terms of spinor coordinates and transform in a nonstandard way under the background supersymmetry. The linear gravitational superfields can be written via spinor derivatives of nonanalytic spinor prepotentials. The perturbative expansion of supergravity action in terms of the B-covariant superfields and the corresponding version of the differential-geometric formalism are considered. We discuss the dual harmonic representation of the linearized extended supergravity, which corresponds to the dynamical condition of Grassmann analyticity

  12. Background modeling for the GERDA experiment

    Science.gov (United States)

    Becerici-Schmidt, N.; Gerda Collaboration

    2013-08-01

    The neutrinoless double beta (0νββ) decay experiment GERDA at the LNGS of INFN has started physics data taking in November 2011. This paper presents an analysis aimed at understanding and modeling the observed background energy spectrum, which plays an essential role in searches for a rare signal like 0νββ decay. A very promising preliminary model has been obtained, with the systematic uncertainties still under study. Important information can be deduced from the model such as the expected background and its decomposition in the signal region. According to the model the main background contributions around Qββ come from 214Bi, 228Th, 42K, 60Co and α emitting isotopes in the 226Ra decay chain, with a fraction depending on the assumed source positions.

  13. Background modeling for the GERDA experiment

    Energy Technology Data Exchange (ETDEWEB)

    Becerici-Schmidt, N. [Max-Planck-Institut für Physik, München (Germany); Collaboration: GERDA Collaboration

    2013-08-08

    The neutrinoless double beta (0νββ) decay experiment GERDA at the LNGS of INFN has started physics data taking in November 2011. This paper presents an analysis aimed at understanding and modeling the observed background energy spectrum, which plays an essential role in searches for a rare signal like 0νββ decay. A very promising preliminary model has been obtained, with the systematic uncertainties still under study. Important information can be deduced from the model such as the expected background and its decomposition in the signal region. According to the model the main background contributions around Q{sub ββ} come from {sup 214}Bi, {sup 228}Th, {sup 42}K, {sup 60}Co and α emitting isotopes in the {sup 226}Ra decay chain, with a fraction depending on the assumed source positions.

  14. In-beam background suppression shield

    DEFF Research Database (Denmark)

    Santoro, V.; Cai, Xiao Xiao; DiJulio, D. D.

    2015-01-01

    The long (3 ms) proton pulse of the European Spallation Source (ESS) gives rise to unique and potentially high backgrounds for the instrument suite. In such a source an instrument's capabilities will be limited by its Signal to Noise (S/N) ratio. The instruments with a direct view of the moderator......, which do not use a bender to help mitigate the fast neutron background, are the most challenging. For these beam lines we propose the innovative shielding of placing blocks of material directly into the guide system, which allow a minimum attenuation of the cold and thermal fluxes relative...... to the background suppression. This shielding configuration has been worked into a beam line model using Geant4. We study particularly the advantages of single crystal sapphire and silicon blocks....

  15. Background Model for the Majorana Demonstrator

    Science.gov (United States)

    Cuesta, C.; Abgrall, N.; Aguayo, E.; Avignone, F. T.; Barabash, A. S.; Bertrand, F. E.; Boswell, M.; Brudanin, V.; Busch, M.; Byram, D.; Caldwell, A. S.; Chan, Y.-D.; Christofferson, C. D.; Combs, D. C.; Detwiler, J. A.; Doe, P. J.; Efremenko, Yu.; Egorov, V.; Ejiri, H.; Elliott, S. R.; Fast, J. E.; Finnerty, P.; Fraenkle, F. M.; Galindo-Uribarri, A.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guiseppe, V. E.; Gusev, K.; Hallin, A. L.; Hazama, R.; Hegai, A.; Henning, R.; Hoppe, E. W.; Howard, S.; Howe, M. A.; Keeter, K. J.; Kidd, M. F.; Kochetov, O.; Konovalov, S. I.; Kouzes, R. T.; LaFerriere, B. D.; Leon, J.; Leviner, L. E.; Loach, J. C.; MacMullin, J.; MacMullin, S.; Martin, R. D.; Meijer, S.; Mertens, S.; Nomachi, M.; Orrell, J. L.; O'Shaughnessy, C.; Overman, N. R.; Phillips, D. G.; Poon, A. W. P.; Pushkin, K.; Radford, D. C.; Rager, J.; Rielage, K.; Robertson, R. G. H.; Romero-Romero, E.; Ronquest, M. C.; Schubert, A. G.; Shanks, B.; Shima, T.; Shirchenko, M.; Snavely, K. J.; Snyder, N.; Suriano, A. M.; Thompson, J.; Timkin, V.; Tornow, W.; Trimble, J. E.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Young, A. R.; Yu, C.-H.; Yumatov, V.

    The Majorana Collaboration is constructing a system containing 40 kg of HPGe detectors to demonstrate the feasibility and potential of a future tonne-scale experiment capable of probing the neutrino mass scale in the inverted-hierarchy region. To realize this, a major goal of the Majorana Demonstrator is to demonstrate a path forward to achieving a background rate at or below 1 cnt/(ROI-t-y) in the 4 keV region of interest around the Q-value at 2039 keV. This goal is pursued through a combination of a significant reduction of radioactive impurities in construction materials with analytical methods for background rejection, for example using powerful pulse shape analysis techniques profiting from the p-type point contact HPGe detectors technology. The effectiveness of these methods is assessed using simulations of the different background components whose purity levels are constrained from radioassay measurements.

  16. Background compensation for a radiation level monitor

    Science.gov (United States)

    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.

  17. Non-perturbative background field calculations

    International Nuclear Information System (INIS)

    Stephens, C.R.; Department of Physics, University of Utah, Salt Lake City, Utah 84112)

    1988-01-01

    New methods are developed for calculating one loop functional determinants in quantum field theory. Instead of relying on a calculation of all the eigenvalues of the small fluctuation equation, these techniques exploit the ability of the proper time formalism to reformulate an infinite dimensional field theoretic problem into a finite dimensional covariant quantum mechanical analog, thereby allowing powerful tools such as the method of Jacobi fields to be used advantageously in a field theory setting. More generally the methods developed herein should be extremely valuable when calculating quantum processes in non-constant background fields, offering a utilitarian alternative to the two standard methods of calculation: perturbation theory in the background field or taking the background field into account exactly. The formalism developed also allows for the approximate calculation of covariances of partial differential equations from a knowledge of the solutions of a homogeneous ordinary differential equation. copyright 1988 Academic Press, Inc

  18. Origin of the diffuse background gamma radiation

    International Nuclear Information System (INIS)

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

    1974-05-01

    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 were 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 formation 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. (U.S.)

  19. Cosmic microwave background distortions at high frequencies

    International Nuclear Information System (INIS)

    Peter, W.; Peratt, A.L.

    1988-01-01

    The authors analyze the deviation of the cosmic background radiation spectrum from the 2.76+-0.02 0 Κ blackbody curve. If the cosmic background radiation is due to absorption and re-emission of synchrotron radiation from galactic-width current filaments, higher-order synchrotron modes are less thermalized than lower-order modes, causing a distortion of the blackbody curve at higher frequencies. New observations of the microwave background spectrum at short wavelengths should provide an indication of the number of synchrotron modes thermalized in this process. The deviation of the spectrum from that of a perfect blackbody can thus be correlated with astronomical observations such as filament temperatures and electron energies. The results are discussed and compared with the theoretical predictions of other models which assume the presence of intergalactic superconducting cosmic strings

  20. Non-perturbative background field calculations

    Science.gov (United States)

    Stephens, C. R.

    1988-01-01

    New methods are developed for calculating one loop functional determinants in quantum field theory. Instead of relying on a calculation of all the eigenvalues of the small fluctuation equation, these techniques exploit the ability of the proper time formalism to reformulate an infinite dimensional field theoretic problem into a finite dimensional covariant quantum mechanical analog, thereby allowing powerful tools such as the method of Jacobi fields to be used advantageously in a field theory setting. More generally the methods developed herein should be extremely valuable when calculating quantum processes in non-constant background fields, offering a utilitarian alternative to the two standard methods of calculation—perturbation theory in the background field or taking the background field into account exactly. The formalism developed also allows for the approximate calculation of covariances of partial differential equations from a knowledge of the solutions of a homogeneous ordinary differential equation.

  1. Background characterization for the GERDA experiment

    Energy Technology Data Exchange (ETDEWEB)

    Becerici-Schmidt, Neslihan [Max-Planck-Institut fuer Physik, Muenchen (Germany); Collaboration: GERDA-Collaboration

    2013-07-01

    The GERmanium Detector Array (Gerda) experiment at the LNGS laboratory of INFN searches for the neutrinoless double beta (0νββ) decay of {sup 76}Ge. A discovery of this decay can greatly advance our knowledge on the nature and properties of neutrinos. The current best limit on the half-life of {sup 76}Ge 0νββ decay is 1.9 . 10{sup 25} years (90% C.L.). In order to increase the sensitivity on the half-life with respect to past experiments, the background rate in the energy region of interest (ROI) around Q{sub ββ} = 2039 keV has been reduced by a factor 10. Gerda started data-taking with the full set of Phase I detectors in November 2011. Identification of the background in the first phase of the experiment is of major importance to further mitigate the background for Gerda Phase II. An analysis of the Phase I data resulted in a good understanding of the individual components in the Gerda background spectrum. The background components in the ROI have been identified to be mainly due to β- and γ-induced events originating from {sup 214}Bi ({sup 238}U-series), {sup 208}Tl ({sup 232}Th-series), {sup 42}K (progeny of {sup 42}Ar) and α-induced events coming from isotopes in the {sup 226}Ra decay chain. A background decomposition in the ROI will be presented, with a special emphasis on the contribution from α-induced events.

  2. Background simulation for the GENIUS project

    International Nuclear Information System (INIS)

    Ponkratenko, O.A.; Tretyak, V.I.; Zdesenko, Yu.G.

    1999-01-01

    The background simulations for the GENIUS experiment were performed with the help of GEANT 3.21 package and event generator DECAY 4.Contributions from the cosmogenic activity produced in the Ge detectors and from its radioactive impurities as well as from contamination of the liquid nitrogen and other materials were calculated.External gamma and neutron background were taking into consideration also.The results of calculations evidently show feasibility of the GENIUS project,which can substantially promote development of modern astroparticle physics

  3. Electromagnetic wave collapse in a radiation background

    International Nuclear Information System (INIS)

    Marklund, Mattias; Brodin, Gert; Stenflo, Lennart

    2003-01-01

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

  4. Optimization of the ECT background coil

    International Nuclear Information System (INIS)

    Ballou, J.K.; Luton, J.N.

    1975-01-01

    This study was begun to optimize the Eccentric Coil Test (ECT) background coil. In the course of this work a general optimization code was obtained, tested, and applied to the ECT problem. So far this code has proven to be very satisfactory. The results obtained with this code and earlier codes have illustrated the parametric behavior of such a coil system and that the optimum for this type system is broad. This study also shows that a background coil with a winding current density of less than 3000 A/cm 2 is not feasible for the ECT models presented in this paper

  5. Elastic lattice in an incommensurate background

    International Nuclear Information System (INIS)

    Dickman, R.; Chudnovsky, E.M.

    1995-01-01

    We study a harmonic triangular lattice, which relaxes in the presence of an incommensurate short-wavelength potential. Monte Carlo simulations reveal that the elastic lattice exhibits only short-ranged translational correlations, despite the absence of defects in either lattice. Extended orientational order, however, persists in the presence of the background. Translational correlation lengths exhibit approximate power-law dependence upon cooling rate and background strength. Our results may be relevant to Wigner crystals, atomic monolayers on crystals surfaces, and flux-line and magnetic bubble lattices

  6. Cognitive psychology and depth psychology backgrounds

    International Nuclear Information System (INIS)

    Fritzsche, A.F.

    1986-01-01

    The sixth chapter gives an insight into the risk perception process which is highly determined by emotions, and, thus, deals with the psychological backgrounds of both the conscious cognitive and the subconscious intuitive realms of the human psyche. The chapter deals with the formation of opinion and the origination of an attitude towards an issue; cognitive-psychological patterns of thinking from the field of risk perception; the question of man's rationality; pertinent aspects of group behaviour; depth psychological backgrounds of the fear of technology; the collective subconscious; nuclear energy as a preferred object of projection for various psychological problems of modern man. (HSCH) [de

  7. Conserved quantities in background independent theories

    Energy Technology Data Exchange (ETDEWEB)

    Markopoulou, Fotini [Perimeter Institute for Theoretical Physics, 35 King Street North, Waterloo, Ontario N2J 2W9 (Canada); Department of Physics, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada)

    2007-05-15

    We discuss the difficulties that background independent theories based on quantum geometry encounter in deriving general relativity as the low energy limit. We follow a geometrogenesis scenario of a phase transition from a pre-geometric theory to a geometric phase which suggests that a first step towards the low energy limit is searching for the effective collective excitations that will characterize it. Using the correspondence between the pre-geometric background independent theory and a quantum information processor, we are able to use the method of noiseless subsystems to extract such coherent collective excitations. We illustrate this in the case of locally evolving graphs.

  8. Fermionic bound states in distinct kinklike backgrounds

    Energy Technology Data Exchange (ETDEWEB)

    Bazeia, D. [Universidade Federal da Paraiba, Departamento de Fisica, Joao Pessoa, Paraiba (Brazil); Mohammadi, A. [Universidade Federal de Campina Grande, Departamento de Fisica, Caixa Postal 10071, Campina Grande, Paraiba (Brazil)

    2017-04-15

    This work deals with fermions in the background of distinct localized structures in the two-dimensional spacetime. Although the structures have a similar topological character, which is responsible for the appearance of fractionally charged excitations, we want to investigate how the geometric deformations that appear in the localized structures contribute to the change in the physical properties of the fermionic bound states. We investigate the two-kink and compact kinklike backgrounds, and we consider two distinct boson-fermion interactions, one motivated by supersymmetry and the other described by the standard Yukawa coupling. (orig.)

  9. A low background pulsed neutron polyenergetic beam

    International Nuclear Information System (INIS)

    Adib, M.; Abdelkawy, A.; Habib, N.; abuelela, M.; Wahba, M.; kilany, M.; Kalebebin, S.M.

    1992-01-01

    A low background pulsed neutron polyenergetic thermal beam at ET-R R-1 is produced by a rotor and rotating collimator suspended in magnetic fields. Each of them is mounted on its mobile platform and whose centres are 66 cm apart, rotating synchronously at speeds up to 16000 rpm. It was found that the neutron burst produced by the rotor with almost 100% transmission passes through the collimator, when the rotation phase between them is 28.8 degree Moreover the background level achieved at the detector position is low, constant and free from peaks due to gamma rays and fast neutrons accompanying the reactor thermal beam.3 fig

  10. Noise correlations in cosmic microwave background experiments

    Science.gov (United States)

    Dodelson, Scott; Kosowsky, Arthur; Myers, Steven T.

    1995-01-01

    Many analysis of microwave background experiments neglect the correlation of noise in different frequency of polarization channels. We show that these correlations, should they be present, can lead to serve misinterpretation of an experiment. In particular, correlated noise arising from either electronics or atmosphere may mimic a cosmic signal. We quantify how the likelihood function for a given experiment varies with noise correlation, using both simple analytic models and actual data. For a typical microwave background anisotropy experiment, noise correlations at the level of 1% of the overall noise can seriously reduce the significance of a given detection.

  11. Cosmic microwave background probes models of inflation

    Science.gov (United States)

    Davis, Richard L.; Hodges, Hardy M.; Smoot, George F.; Steinhardt, Paul J.; Turner, Michael S.

    1992-01-01

    Inflation creates both scalar (density) and tensor (gravity wave) metric perturbations. We find that the tensor-mode contribution to the cosmic microwave background anisotropy on large-angular scales can only exceed that of the scalar mode in models where the spectrum of perturbations deviates significantly from scale invariance. If the tensor mode dominates at large-angular scales, then the value of DeltaT/T predicted on 1 deg is less than if the scalar mode dominates, and, for cold-dark-matter models, bias factors greater than 1 can be made consistent with Cosmic Background Explorer (COBE) DMR results.

  12. Cosmic microwave background at its twentieth anniversary

    International Nuclear Information System (INIS)

    Partridge, R.B.

    1986-01-01

    The role of cosmic microwave background radiation in cosmology is examined. The thermal spectrum, the large entropy in the universe, the large-scale isotropy of the radiation, and the small-scale isotropy or homogeneity of the radiation are analyzed in order to describe the properties of the universe. It is observed that the microwave background spectrum is thermal over a wide range, there is a significant detectable dipole anisotropy in the radiation, but no quadrupole anisotropy, and there is a high deree of radiation isotropy on angular scales between 1-5 degrees. 62 references

  13. Natural background radiation and oncologic disease incidence

    International Nuclear Information System (INIS)

    Burenin, P.I.

    1982-01-01

    Cause and effect relationships between oncologic disease incidence in human population and environmental factors are examined using investigation materials of Soviet and foreign authors. The data concerning US white population are adduced. The role and contribution of natural background radiation oncologic disease prevalence have been determined with the help of system information analysis. The probable damage of oncologic disease is shown to decrease as the background radiation level diminishes. The linear nature of dose-response relationspip has been established. The necessity to include the life history of the studied population along with environmental factors in epidemiological study under conditions of multiplicity of cancerogenesis causes is emphasized

  14. Does Social Background Influence Political Science Grades?

    Science.gov (United States)

    Tiruneh, Gizachew

    2013-01-01

    This paper tests a hypothesized linear relationship between social background and final grades in several political science courses that I taught at the University of Central Arkansas. I employ a cross-sectional research design and ordinary least square (OLS) estimators to test the foregoing hypothesis. Relying on a sample of up to 204…

  15. Physiologic correlates to background noise acceptance

    Science.gov (United States)

    Tampas, Joanna; Harkrider, Ashley; Nabelek, Anna

    2004-05-01

    Acceptance of background noise can be evaluated by having listeners indicate the highest background noise level (BNL) they are willing to accept while following the words of a story presented at their most comfortable listening level (MCL). The difference between the selected MCL and BNL is termed the acceptable noise level (ANL). One of the consistent findings in previous studies of ANL is large intersubject variability in acceptance of background noise. This variability is not related to age, gender, hearing sensitivity, personality, type of background noise, or speech perception in noise performance. The purpose of the current experiment was to determine if individual differences in physiological activity measured from the peripheral and central auditory systems of young female adults with normal hearing can account for the variability observed in ANL. Correlations between ANL and various physiological responses, including spontaneous, click-evoked, and distortion-product otoacoustic emissions, auditory brainstem and middle latency evoked potentials, and electroencephalography will be presented. Results may increase understanding of the regions of the auditory system that contribute to individual noise acceptance.

  16. Egypt: Background and U.S. Relations

    Science.gov (United States)

    2013-06-27

    right to govern; the more the Brotherhood charges ahead, the more it confirms the others’ belief of its monopolistic designs over power. Even if...appropriate market -reform and economic growth activities.” Egypt: Background and U.S. Relations Congressional Research Service 18 according to the State

  17. Natural background approach to setting radiation standards

    International Nuclear Information System (INIS)

    Adler, H.I.; Federow, H.; Weinberg, A.M.

    1979-01-01

    The suggestion has often been made that an additional radiation exposure imposed on humanity as a result of some important activity such as electricity generation would be acceptable if the exposure was small compared to the natural background. In order to make this concept quantitative and objective, we propose that small compared with the natural background be interpreted as the standard deviation (weighted with the exposed population) of the natural background. This use of the variation in natural background radiation is less arbitrary and requires fewer unfounded assumptions than some current approaches to standard-setting. The standard deviation is an easily calculated statistic that is small compared with the mean value for natural exposures of populations. It is an objectively determined quantity and its significance is generally understood. Its determination does not omit any of the pertinent data. When this method is applied to the population of the United States, it suggests that a dose of 20 mrem/year would be an acceptable standard. This is comparable to the 25 mrem/year suggested as the maximum allowable exposure to an individual from the complete uranium fuel cycle

  18. 20 CFR 410.700 - Background.

    Science.gov (United States)

    2010-04-01

    ... LUNG BENEFITS (1969- ) Rules for the Review of Denied and Pending Claims Under the Black Lung Benefits Reform Act (BLBRA) of 1977 § 410.700 Background. (a) The Black Lung Benefits Reform Act of 1977 broadens... establish entitlement to black lung benefits. Section 435 of the Black Lung Benefits Reform Act of 1977...

  19. The projected background for the CUORE experiment

    Energy Technology Data Exchange (ETDEWEB)

    Alduino, C.; Avignone, F.T.; Chott, N.; Creswick, R.J.; Rosenfeld, C.; Wilson, J. [University of South Carolina, Department of Physics and Astronomy, Columbia, SC (United States); Alfonso, K.; Hickerson, K.P.; Huang, H.Z.; Sakai, M.; Schmidt, J.; Trentalange, S.; Zhu, B.X. [University of California, Department of Physics and Astronomy, Los Angeles, CA (United States); Artusa, D.R.; Rusconi, C. [University of South Carolina, Department of Physics and Astronomy, Columbia, SC (United States); INFN-Laboratori Nazionali del Gran Sasso, L' Aquila (Italy); Azzolini, O.; Camacho, A.; Keppel, G.; Palmieri, V.; Pira, C. [INFN-Laboratori Nazionali di Legnaro, Padua (Italy); Banks, T.I.; Drobizhev, A.; Freedman, S.J.; Hennings-Yeomans, R.; Kolomensky, Yu.G.; Wagaarachchi, S.L. [University of California, Department of Physics, Berkeley, CA (United States); Lawrence Berkeley National Laboratory, Nuclear Science Division, Berkeley, CA (United States); Bari, G.; Deninno, M.M. [INFN-Sezione di Bologna, Bologna (Italy); Beeman, J.W. [Lawrence Berkeley National Laboratory, Materials Science Division, Berkeley, CA (United States); Bellini, F.; Cosmelli, C.; Ferroni, F.; Piperno, G. [Sapienza Universita di Roma, Dipartimento di Fisica, Rome (Italy); INFN-Sezione di Roma, Rome (Italy); Benato, G.; Singh, V. [University of California, Department of Physics, Berkeley, CA (United States); Bersani, A.; Caminata, A. [INFN-Sezione di Genova, Genoa (Italy); Biassoni, M.; Brofferio, C.; Capelli, S.; Carniti, P.; Cassina, L.; Chiesa, D.; Clemenza, M.; Faverzani, M.; Fiorini, E.; Gironi, L.; Gotti, C.; Maino, M.; Nastasi, M.; Nucciotti, A.; Pavan, M.; Pozzi, S.; Sisti, M.; Terranova, F.; Zanotti, L. [Universita di Milano-Bicocca, Dipartimento di Fisica, Milan (Italy); INFN-Sezione di Milano Bicocca, Milan (Italy); Branca, A.; Taffarello, L. [INFN-Sezione di Padova, Padua (Italy); Bucci, C.; Cappelli, L.; D' Addabbo, A.; Gorla, P.; Pattavina, L.; Pirro, S.; Laubenstein, M. [INFN-Laboratori Nazionali del Gran Sasso, L' Aquila (Italy); Canonica, L. [INFN-Laboratori Nazionali del Gran Sasso, L' Aquila (Italy); Massachusetts Institute of Technology, Cambridge, MA (United States); Cao, X.G.; Fang, D.Q.; Ma, Y.G.; Wang, H.W.; Zhang, G.Q. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai (China); Carbone, L.; Cremonesi, O.; Ferri, E.; Giachero, A.; Pessina, G.; Previtali, E. [INFN-Sezione di Milano Bicocca, Milan (Italy); Cardani, L.; Casali, N.; Dafinei, I.; Morganti, S.; Mosteiro, P.J.; Pettinacci, V.; Tomei, C.; Vignati, M. [INFN-Sezione di Roma, Rome (Italy); Copello, S.; Di Domizio, S.; Fernandes, G.; Marini, L.; Pallavicini, M. [INFN-Sezione di Genova, Genoa (Italy); Universita di Genova, Dipartimento di Fisica, Genoa (Italy); Cushman, J.S.; Davis, C.J.; Heeger, K.M.; Lim, K.E.; Maruyama, R.H. [Yale University, Department of Physics, New Haven, CT (United States); Dell' Oro, S. [INFN-Laboratori Nazionali del Gran Sasso, L' Aquila (Italy); INFN-Gran Sasso Science Institute, L' Aquila (Italy); Di Vacri, M.L.; Santone, D. [INFN-Laboratori Nazionali del Gran Sasso, L' Aquila (Italy); Universita dell' Aquila, Dipartimento di Scienze Fisiche e Chimiche, L' Aquila (Italy); Franceschi, M.A.; Ligi, C.; Napolitano, T. [INFN-Laboratori Nazionali di Frascati, Rome (Italy); Fujikawa, B.K.; Mei, Y.; Schmidt, B.; Smith, A.R.; Welliver, B. [Lawrence Berkeley National Laboratory, Nuclear Science Division, Berkeley, CA (United States); Giuliani, A.; Novati, V.; Tenconi, M. [Universit Paris-Saclay, CSNSM, Univ. Paris-Sud, CNRS/IN2P3, Orsay (France); Gladstone, L.; Leder, A.; Ouellet, J.L.; Winslow, L.A. [Massachusetts Institute of Technology, Cambridge, MA (United States); Gutierrez, T.D. [California Polytechnic State University, Physics Department, San Luis Obispo, CA (United States); Haller, E.E. [Lawrence Berkeley National Laboratory, Materials Science Division, Berkeley, CA (United States); University of California, Department of Materials Science and Engineering, Berkeley, CA (United States); Han, K. [Shanghai Jiao Tong University, Department of Physics and Astronomy, Shanghai (China); Hansen, E. [University of California, Department of Physics and Astronomy, Los Angeles, CA (United States); Massachusetts Institute of Technology, Cambridge, MA (United States); Kadel, R. [Lawrence Berkeley National Laboratory, Physics Division, Berkeley, CA (United States); Martinez, M. [Sapienza Universita di Roma, Dipartimento di Fisica, Rome (Italy); INFN-Sezione di Roma, Rome (Italy); Universidad de Zaragoza, Laboratorio de Fisica Nuclear y Astroparticulas, Zaragoza (Spain); Moggi, N. [INFN-Sezione di Bologna, Bologna (Italy); Alma Mater Studiorum-Universita di Bologna, Dipartimento di Scienze per la Qualita della Vita, Bologna (Italy); Nones, C. [CEA/Saclay, Service de Physique des Particules, Gif-sur-Yvette (France); Norman, E.B.; Wang, B.S. [Lawrence Livermore National Laboratory, Livermore, CA (United States); University of California, Department of Nuclear Engineering, Berkeley, CA (United States); O' Donnell, T. [Virginia Polytechnic Institute and State University, Center for Neutrino Physics, Blacksburg, VA (United States); Pagliarone, C.E. [INFN-Laboratori Nazionali del Gran Sasso, L' Aquila (Italy); Universita degli Studi di Cassino e del Lazio Meridionale, Dipartimento di Ingegneria Civile e Meccanica, Cassino (Italy); Sangiorgio, S.; Scielzo, N.D. [Lawrence Livermore National Laboratory, Livermore, CA (United States); Wise, T. [Yale University, Department of Physics, New Haven, CT (United States); University of Wisconsin, Department of Physics, Madison, WI (United States); Woodcraft, A. [University of Edinburgh, SUPA, Institute for Astronomy, Edinburgh (United Kingdom); Zimmermann, S. [Lawrence Berkeley National Laboratory, Engineering Division, Berkeley, CA (United States); Zucchelli, S. [INFN-Sezione di Bologna, Bologna (Italy); Alma Mater Studiorum-Universita di Bologna, Dipartimento di Fisica e Astronomia, Bologna (Italy)

    2017-08-15

    The Cryogenic Underground Observatory for Rare Events (CUORE) is designed to search for neutrinoless double beta decay of {sup 130}Te with an array of 988 TeO{sub 2} bolometers operating at temperatures around 10 mK. The experiment is currently being commissioned in Hall A of Laboratori Nazionali del Gran Sasso, Italy. The goal of CUORE is to reach a 90% C.L. exclusion sensitivity on the {sup 130}Te decay half-life of 9 x 10{sup 25} years after 5 years of data taking. The main issue to be addressed to accomplish this aim is the rate of background events in the region of interest, which must not be higher than 10{sup -2} counts/keV/kg/year. We developed a detailed Monte Carlo simulation, based on results from a campaign of material screening, radioassays, and bolometric measurements, to evaluate the expected background. This was used over the years to guide the construction strategies of the experiment and we use it here to project a background model for CUORE. In this paper we report the results of our study and our expectations for the background rate in the energy region where the peak signature of neutrinoless double beta decay of {sup 130}Te is expected. (orig.)

  20. Bloemfontein's Greek community: historical background, emigration ...

    African Journals Online (AJOL)

    Bloemfontein's Greek community: historical background, emigration and settlement, ca 1885 - ca 1985. ... South African Journal of Cultural History ... In this study a review is provided of the reasons why Greeks settled in Bloemfontein since about 1885, where these Greek immigrants came from, and how they travelled to ...

  1. Racial background and possible relationships between physical ...

    African Journals Online (AJOL)

    The aim of this research was to investigate possible relationships between physical activity and physical fitness of girls between the ages of 13 and 15 years and the role of different racial backgrounds in this relationship. A cross-sectional research design was used to obtain information from 290 girls between the ages of 13 ...

  2. Controllable forms of natural background radiation

    International Nuclear Information System (INIS)

    1988-03-01

    RENA is a research programm into the controllable forms of natural background radiation, which cover the activities originating from the naturally occurring radionuclides enhanced by human intervention. In the RENA-program emphasis lays upon the policy aspects of environmental-hygienic, economical and governmental character. (H.W.). 15 refs.; 2 tabs

  3. 44 CFR 334.3 - Background.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Background. 334.3 Section 334.3 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND... take into account the need to mobilize the Nation's resources in response to a wide range of crisis or...

  4. ttH multilepton: background estimation

    CERN Document Server

    Angelidakis, Stylianos; The ATLAS collaboration

    2018-01-01

    The slides present the background encountered in the ttH->Multilepton search and describe the data-driven techniques used for the determination of the dominant non-prompt-lepton contamination as well as the contribution of electron charge mis-identification.

  5. Climate change: Scientific background and process

    OpenAIRE

    Alfsen, Knut H.; Fuglestvedt, Jan S.; Seip, Hans Martin; Skodvin, Tora

    2000-01-01

    The paper gives a brief description of natural and man-made forces behind climate change and outlines climate variations in the past together with a brief synopsis likely future impacts of anthropogenic emissions of greenhouse gases. The paper also gives a briefing on the background, organisation and functioning of the Intergovernmental Panel on Climate Change (IPCC).

  6. On the maximal superalgebras of supersymmetric backgrounds

    International Nuclear Information System (INIS)

    Figueroa-O'Farrill, Jose; Hackett-Jones, Emily; Moutsopoulos, George; Simon, Joan

    2009-01-01

    In this paper we give a precise definition of the notion of a maximal superalgebra of certain types of supersymmetric supergravity backgrounds, including the Freund-Rubin backgrounds, and propose a geometric construction extending the well-known construction of its Killing superalgebra. We determine the structure of maximal Lie superalgebras and show that there is a finite number of isomorphism classes, all related via contractions from an orthosymplectic Lie superalgebra. We use the structure theory to show that maximally supersymmetric waves do not possess such a maximal superalgebra, but that the maximally supersymmetric Freund-Rubin backgrounds do. We perform the explicit geometric construction of the maximal superalgebra of AdS 4 X S 7 and find that it is isomorphic to osp(1|32). We propose an algebraic construction of the maximal superalgebra of any background asymptotic to AdS 4 X S 7 and we test this proposal by computing the maximal superalgebra of the M2-brane in its two maximally supersymmetric limits, finding agreement.

  7. Background reduction in a young interferometer biosensor

    NARCIS (Netherlands)

    Mulder, H. K P; Subramaniam, V.; Kanger, J. S.

    2014-01-01

    Integrated optical Young interferometer (IOYI) biosensors are among the most sensitive label-free biosensors. Detection limits are in the range of 20 fg/mm2. The applicability of these sensors is however strongly hampered by the large background that originates from both bulk refractive index

  8. Probabilistic Model-based Background Subtraction

    DEFF Research Database (Denmark)

    Krüger, Volker; Anderson, Jakob; Prehn, Thomas

    2005-01-01

    is the correlation between pixels. In this paper we introduce a model-based background subtraction approach which facilitates prior knowledge of pixel correlations for clearer and better results. Model knowledge is being learned from good training video data, the data is stored for fast access in a hierarchical...

  9. The projected background for the CUORE experiment

    Science.gov (United States)

    Alduino, C.; Alfonso, K.; Artusa, D. R.; Avignone, F. T.; Azzolini, O.; Banks, T. I.; Bari, G.; Beeman, J. W.; Bellini, F.; Benato, G.; Bersani, A.; Biassoni, M.; Branca, A.; Brofferio, C.; Bucci, C.; Camacho, A.; Caminata, A.; Canonica, L.; Cao, X. G.; Capelli, S.; Cappelli, L.; Carbone, L.; Cardani, L.; Carniti, P.; Casali, N.; Cassina, L.; Chiesa, D.; Chott, N.; Clemenza, M.; Copello, S.; Cosmelli, C.; Cremonesi, O.; Creswick, R. J.; Cushman, J. S.; D'Addabbo, A.; Dafinei, I.; Davis, C. J.; Dell'Oro, S.; Deninno, M. M.; Di Domizio, S.; Di Vacri, M. L.; Drobizhev, A.; Fang, D. Q.; Faverzani, M.; Fernandes, G.; Ferri, E.; Ferroni, F.; Fiorini, E.; Franceschi, M. A.; Freedman, S. J.; Fujikawa, B. K.; Giachero, A.; Gironi, L.; Giuliani, A.; Gladstone, L.; Gorla, P.; Gotti, C.; Gutierrez, T. D.; Haller, E. E.; Han, K.; Hansen, E.; Heeger, K. M.; Hennings-Yeomans, R.; Hickerson, K. P.; Huang, H. Z.; Kadel, R.; Keppel, G.; Kolomensky, Yu. G.; Leder, A.; Ligi, C.; Lim, K. E.; Ma, Y. G.; Maino, M.; Marini, L.; Martinez, M.; Maruyama, R. H.; Mei, Y.; Moggi, N.; Morganti, S.; Mosteiro, P. J.; Napolitano, T.; Nastasi, M.; Nones, C.; Norman, E. B.; Novati, V.; Nucciotti, A.; O'Donnell, T.; Ouellet, J. L.; Pagliarone, C. E.; Pallavicini, M.; Palmieri, V.; Pattavina, L.; Pavan, M.; Pessina, G.; Pettinacci, V.; Piperno, G.; Pira, C.; Pirro, S.; Pozzi, S.; Previtali, E.; Rosenfeld, C.; Rusconi, C.; Sakai, M.; Sangiorgio, S.; Santone, D.; Schmidt, B.; Schmidt, J.; Scielzo, N. D.; Singh, V.; Sisti, M.; Smith, A. R.; Taffarello, L.; Tenconi, M.; Terranova, F.; Tomei, C.; Trentalange, S.; Vignati, M.; Wagaarachchi, S. L.; Wang, B. S.; Wang, H. W.; Welliver, B.; Wilson, J.; Winslow, L. A.; Wise, T.; Woodcraft, A.; Zanotti, L.; Zhang, G. Q.; Zhu, B. X.; Zimmermann, S.; Zucchelli, S.; Laubenstein, M.

    2017-08-01

    The Cryogenic Underground Observatory for Rare Events (CUORE) is designed to search for neutrinoless double beta decay of ^{130}Te with an array of 988 TeO_2 bolometers operating at temperatures around 10 mK. The experiment is currently being commissioned in Hall A of Laboratori Nazionali del Gran Sasso, Italy. The goal of CUORE is to reach a 90% C.L. exclusion sensitivity on the ^{130}Te decay half-life of 9 × 10^{25} years after 5 years of data taking. The main issue to be addressed to accomplish this aim is the rate of background events in the region of interest, which must not be higher than 10^{-2} counts/keV/kg/year. We developed a detailed Monte Carlo simulation, based on results from a campaign of material screening, radioassays, and bolometric measurements, to evaluate the expected background. This was used over the years to guide the construction strategies of the experiment and we use it here to project a background model for CUORE. In this paper we report the results of our study and our expectations for the background rate in the energy region where the peak signature of neutrinoless double beta decay of ^{130}Te is expected.

  10. 42 CFR 81.0 - Background.

    Science.gov (United States)

    2010-10-01

    ... HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND... OCCUPATIONAL ILLNESS COMPENSATION PROGRAM ACT OF 2000 Introduction § 81.0 Background. The Energy Employees Occupational Illness Compensation Program Act (EEOICPA), 42 U.S.C. 7384-7385 [1994, supp. 2001], provides for...

  11. Spectrum of the extragalactic background light

    Energy Technology Data Exchange (ETDEWEB)

    Bruzual A, G [Centro de Investigacion de Astronomia, Merida (Venezuela)

    1981-01-01

    The observed spectrum of the extragalactic background light in the range from ultraviolet to optical wavelengths is compared with a model prediction. The model uses the locally observed luminosity function of galaxies as well as evolutionary models for galaxy spectral energy distributions. The predicition is too faint by a factor of about 10.

  12. 32 CFR 701.40 - Background.

    Science.gov (United States)

    2010-07-01

    ... OFFICIAL RECORDS AVAILABILITY OF DEPARTMENT OF THE NAVY RECORDS AND PUBLICATION OF DEPARTMENT OF THE NAVY DOCUMENTS AFFECTING THE PUBLIC FOIA Fees § 701.40 Background. (a) The DON follows the uniform fee schedule... Freedom of Information Act Fee Schedule and Guidelines. (b) Fees reflect direct costs for search; review...

  13. The spinorial method of classifying supersymmetric backgrounds

    NARCIS (Netherlands)

    Gran, U.; Gutowski, J.; Papadopoulos, G.; Roest, D.

    2006-01-01

    We review how the classification of all supersymmetric backgrounds of IIB supergravity can be reduced to the evaluation of the Killing spinor equations and their integrability conditions, which contain the field equations, on five types of spinors. This is an extension of the work [hep-th/0503046

  14. Dim point target detection against bright background

    Science.gov (United States)

    Zhang, Yao; Zhang, Qiheng; Xu, Zhiyong; Xu, Junping

    2010-05-01

    For target detection within a large-field cluttered background from a long distance, several difficulties, involving low contrast between target and background, little occupancy, illumination ununiformity caused by vignetting of lens, and system noise, make it a challenging problem. The existing approaches to dim target detection can be roughly divided into two categories: detection before tracking (DBT) and tracking before detection (TBD). The DBT-based scheme has been widely used in practical applications due to its simplicity, but it often requires working in the situation with a higher signal-to-noise ratio (SNR). In contrast, the TBD-based methods can provide impressive detection results even in the cases of very low SNR; unfortunately, the large memory requirement and high computational load prevents these methods from real-time tasks. In this paper, we propose a new method for dim target detection. We address this problem by combining the advantages of the DBT-based scheme in computational efficiency and of the TBD-based in detection capability. Our method first predicts the local background, and then employs the energy accumulation and median filter to remove background clutter. The dim target is finally located by double window filtering together with an improved high order correlation which speeds up the convergence. The proposed method is implemented on a hardware platform and performs suitably in outside experiments.

  15. Classification of supersymmetric backgrounds of string theory

    NARCIS (Netherlands)

    Gran, Ulf; Gutowski, Jan; Papadopoulos, George; Roest, Diederik

    2007-01-01

    We review the recent progress made towards the classification of supersymmetric solutions in ten and eleven dimensions with emphasis on those of IIB supergravity. In particular, the spinorial geometry method is outlined and adapted to nearly maximally supersymmetric backgrounds.We then demonstrate

  16. Climate change. Scientific background and process

    Energy Technology Data Exchange (ETDEWEB)

    Alfsen, Knut H; Fuglestvedt, Jan; Seip, Hans Martin; Skodvin, Tora

    1999-07-01

    The paper describes briefly the natural and man-made forces behind climate change and outlines climate variations in the past. It also discusses the future impact of anthropogenic emission of greenhouse gases, and the background, organisation and functioning of the Intergovernmental Panel on Climate Change (IPCC)

  17. IIB backgrounds with five-form flux

    International Nuclear Information System (INIS)

    Gran, U.; Gutowski, J.; Papadopoulos, G.

    2008-01-01

    We investigate all N=2 supersymmetric IIB supergravity backgrounds with non-vanishing five-form flux. The Killing spinors have stability subgroups Spin(7) x R 8 , SU(4) x R 8 and G 2 . In the SU(4) x R 8 case, two different types of geometry arise depending on whether the Killing spinors are generic or pure. In both cases, the backgrounds admit a null Killing vector field which leaves invariant the SU(4) x R 8 structure, and an almost complex structure in the directions transverse to the lightcone. In the generic case, the twist of the vector field is trivial but the almost complex structure is non-integrable, while in the pure case the twist is non-trivial but the almost complex structure is integrable and associated with a relatively balanced Hermitian structure. The G 2 backgrounds admit a time-like Killing vector field and two spacelike closed one-forms, and the seven directions transverse to these admit a co-symplectic G 2 structure. The Spin(7) x R 8 backgrounds are pp-waves propagating in an eight-dimensional manifold with holonomy Spin(7). In addition we show that all the supersymmetric solutions of simple five-dimensional supergravity with a time-like Killing vector field, which include the AdS 5 black holes, lift to SU(4) x R 8 pure Killing spinor IIB backgrounds. We also show that the LLM solution is associated with a co-symplectic co-homogeneity one G 2 manifold which has principal orbit S 3 xS 3

  18. Background reduction in the SNO+ experiment

    Energy Technology Data Exchange (ETDEWEB)

    Segui, L. [University of Oxford, Denys Wilkinson Building, Keble Road, OX1 Oxford (United Kingdom)

    2015-08-17

    SNO+ is a large multi-purpose liquid scintillator experiment, which first aim is to detect the neutrinoless double beta decay of {sup 130}Te. It is placed at SNOLAB, at 6000 m.w.e. and it is based on the SNO infrastructure. SNO+ will contain approximately 780 tonnes of liquid scintillator, loaded with {sup 130}Te inside an acrylic vessel (AV) with an external volume of ultra pure water to reduce the external backgrounds. Light produced in the scintillator by the interaction of particles will be detected with about 9,000 photomultiplier’s. For the neutrinoless double beta decay phase, due to its the extremely low rate expected, the control, knowledge and reduction of the background is essential. Moreover, it will also benefit other phases of the experiment focused on the study of solar neutrinos, nucleon decay, geoneutrinos and supernovae. In order to reduce the internal background level, a novel purification technique for tellurium loaded scintillators has been developed by the collaboration that reduces the U/Th concentration and several cosmic-activated isotopes by at least a factor 10{sup 2} -10{sup 3} in a single pass. In addition, different rejection techniques have been developed for the remaining internal backgrounds based on Monte-Carlo simulations. In this work, the scintillator purification technique and the levels obtained with it will be discussed. Furthermore, an overview of the different backgrounds for the double-beta phase will be presented, highlighting some of the techniques developed to reject the remained decays based on their expected timing differences.

  19. Spontaneous Radiation Background Calculation for LCLS

    CERN Document Server

    Reiche, Sven

    2004-01-01

    The intensity of undulator radiation, not amplified by the FEL interaction, can be larger than the maximum FEL signal in the case of an X-ray FEL. In the commissioning of a SASE FEL it is essential to extract an amplified signal early to diagnose eventual misalignment of undulator modules or errors in the undulator field strength. We developed a numerical code to calculate the radiation pattern at any position behind a multi-segmented undulator with arbitrary spacing and field profiles. The output can be run through numerical spatial and frequency filters to model the radiation beam transport and diagnostic. In this presentation we estimate the expected background signal for the FEL diagnostic and at what point along the undulator the FEL signal can be separated from the background. We also discusses how much information on the undulator field and alignment can be obtained from the incoherent radiation signal itself.

  20. Topology of microwave background fluctuations - Theory

    Science.gov (United States)

    Gott, J. Richard, III; Park, Changbom; Bies, William E.; Bennett, David P.; Juszkiewicz, Roman

    1990-01-01

    Topological measures are used to characterize the microwave background temperature fluctuations produced by 'standard' scenarios (Gaussian) and by cosmic strings (non-Gaussian). Three topological quantities: total area of the excursion regions, total length, and total curvature (genus) of the isotemperature contours, are studied for simulated Gaussian microwave background anisotropy maps and then compared with those of the non-Gaussian anisotropy pattern produced by cosmic strings. In general, the temperature gradient field shows the non-Gaussian behavior of the string map more distinctively than the temperature field for all topology measures. The total contour length and the genus are found to be more sensitive to the existence of a stringy pattern than the usual temperature histogram. Situations when instrumental noise is superposed on the map, are considered to find the critical signal-to-noise ratio for which strings can be detected.

  1. Global Warming and the Microwave Background

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2009-04-01

    Full Text Available In the work, the importance of assigning the microwave background to the Earth is ad- dressed while emphasizing the consequences for global climate change. Climate mod- els can only produce meaningful forecasts when they consider the real magnitude of all radiative processes. The oceans and continents both contribute to terrestrial emis- sions. However, the extent of oceanic radiation, particularly in the microwave region, raises concerns. This is not only since the globe is covered with water, but because the oceans themselves are likely to be weaker emitters than currently believed. Should the microwave background truly be generated by the oceans of the Earth, our planet would be a much less efficient emitter of radiation in this region of the electromagnetic spectrum. Furthermore, the oceans would appear unable to increase their emissions in the microwave in response to temperature elevation, as predicted by Stefan’s law. The results are significant relative to the modeling of global warming.

  2. Pairing in the cosmic neutrino background

    International Nuclear Information System (INIS)

    Alonso, V.; Paredes, R.

    1981-07-01

    We extend the discussion of the possible superfluidity of the cosmic background of neutrinos beyond the arguments based on the gap equation, originally given by Ginzburg and Zharkov. We show how to develop a simple Ginzburg-Landau liquid model, in analogy with superconductivity. We use it to show how an analysis of the energy spectrum of the universe can be formulated to include general relativistic effects on the superfluid neutrinos. Finally, in view of the Hawking and Collins careful discussion on the rotation and distortion of a spatially homogeneous and isotropic universe, we discuss the vortex dynamics that might be generated on the superfluid by rotations (allowed by the almost isotropy of the microwave background of photons) of up to 2 x 10 -14 second of arc/century, but conclude that rotations of this order of magnitude would be sufficiently strong to deter the existence of the superfluid state. (author)

  3. Partition function for a singular background

    International Nuclear Information System (INIS)

    McKenzie-Smith, J.J.; Naylor, W.

    2005-01-01

    We present a method for evaluating the partition function in a varying external field. Specifically, we look at the case of a non-interacting, charged, massive scalar field at finite temperature with an associated chemical potential in the background of a delta-function potential. Whilst we present a general method, valid at all temperatures, we only give the result for the leading order term in the high temperature limit. Although the derivative expansion breaks down for inhomogeneous backgrounds we are able to obtain the high temperature expansion, as well as an analytic expression for the zero point energy, by way of a different approximation scheme, which we call the local Born approximation (LBA)

  4. Background characterization in a liquid scintillation spectrometer

    International Nuclear Information System (INIS)

    Rodriguez Barquero, L.; Los Arcos, J.M.; Jimenez de Mingo, A.

    1995-01-01

    An alternate procedure for background count rate estimation in a liquid scintillation spectrometer is presented, which does not require to measure a blank with similar composition, volume and quench, to the problem sample. The procedure is based on a double linear parameterization which was obtained from a systematic study of the background observed with glass vials, in three different windows, 0 - 20 KeV, 0 - 800 KeV and 0 - 2 MeV, for volume between 2 and 20 mi of three commercial scintillators, Hisafe II, Ultima-Gold and Instagel, and quenching degree in the interval equivalent to 50% - 3% tritium efficiency. This procedure was tested with standard samples of 3H, and led to average discrepancies less than 10% for activity ≥0,6 Bq, against conventional methods for which the discrepancies are twice on average. (Author) 10 refs

  5. Background characterization in a liquid scintillation spectrometer

    International Nuclear Information System (INIS)

    Rodriguez Barquero, L.; Los arcos, J.M.; Jimenez de Mingo, A.

    1995-01-01

    An alternate procedure for background count rate estimation in a liquid scintillation spectrometer is presented, which does not require to measure a blank with similar composition, volume and quench, to the problem sample. The procedure is based on a double linear parameterization which was obtained from a systematic study of the background observed with glass vials, in three different windows, 0-20 KeV, 0-800 KeV and 0-2 MeV, for volume between 2 and 20 ml of three commercial scintillators, Hisafe II, Ultima-gold and Instagel, and quenching degree in the interval equivalent to 50%-3% tritium efficiency. This procedure was tested with standard samples of ''3 H, and led to average discrepancies less than 10% for activity => 0,6 Bq, against conventional methods for which the discrepancies are twice on average

  6. Neutron stimulated emission computed tomography: Background corrections

    International Nuclear Information System (INIS)

    Floyd, Carey E.; Sharma, Amy C.; Bender, Janelle E.; Kapadia, Anuj J.; Xia, Jessie Q.; Harrawood, Brian P.; Tourassi, Georgia D.; Lo, Joseph Y.; Kiser, Matthew R.; Crowell, Alexander S.; Pedroni, Ronald S.; Macri, Robert A.; Tajima, Shigeyuki; Howell, Calvin R.

    2007-01-01

    Neutron stimulated emission computed tomography (NSECT) is an imaging technique that provides an in-vivo tomographic spectroscopic image of the distribution of elements in a body. To achieve this, a neutron beam illuminates the body. Nuclei in the body along the path of the beam are stimulated by inelastic scattering of the neutrons in the beam and emit characteristic gamma photons whose unique energy identifies the element. The emitted gammas are collected in a spectrometer and form a projection intensity for each spectral line at the projection orientation of the neutron beam. Rotating and translating either the body or the beam will allow a tomographic projection set to be acquired. Images are reconstructed to represent the spatial distribution of elements in the body. Critical to this process is the appropriate removal of background gamma events from the spectrum. Here we demonstrate the equivalence of two background correction techniques and discuss the appropriate application of each

  7. Foreign Energy Company Competitiveness: Background information

    Energy Technology Data Exchange (ETDEWEB)

    Weimar, M.R.; Freund, K.A.; Roop, J.M.

    1994-10-01

    This report provides background information to the report Energy Company Competitiveness: Little to Do With Subsidies (DOE 1994). The main body of this publication consists of data uncovered during the course of research on this DOE report. This data pertains to major government energy policies in each country studied. This report also provides a summary of the DOE report. In October 1993, the Office of Energy Intelligence, US Department of Energy (formerly the Office of Foreign Intelligence), requested that Pacific Northwest Laboratory prepare a report addressing policies and actions used by foreign governments to enhance the competitiveness of their energy firms. Pacific Northwest Laboratory prepared the report Energy Company Competitiveness Little to Do With Subsidies (DOE 1994), which provided the analysis requested by DOE. An appendix was also prepared, which provided extensive background documentation to the analysis. Because of the length of the appendix, Pacific Northwest Laboratory decided to publish this information separately, as contained in this report.

  8. Background paper on Technology Roadmaps (TRMs)

    Energy Technology Data Exchange (ETDEWEB)

    More, E.; Phaal, R. [Institute for Manufacturing IfM, Department of Engineering, University of Cambridge, Cambridge (United Kingdom); Londo, H.M.; Wurtenberger, L.; Cameron, L.R. [ECN Policy Studies, Amsterdam (Netherlands)

    2013-04-15

    This background paper reports on the use of technology roadmaps (TRMs) related to climate change mitigation and adaptation technologies. The study is motivated by the UNFCCC Conference of the Parties (CoP) request to the Technology Executive Committee (TEC) to catalyse the development and use of TRMs as facilitative tools for action on mitigation and adaptation. Having originated in industry, TRMs are now used extensively in policy settings too, however their widespread use across sectors and by different stakeholders has resulted in a lack of understanding of their real value to help catalyse cooperation towards technological solutions to the problems presented by climate change. Consequently this background paper presents (1) an overview of different TRM methods, (2) an initial analysis of gaps and barriers in existing TRMs, and (3) a review of current TRM good practices.

  9. Natural background radiation in Saudi Arabia

    International Nuclear Information System (INIS)

    Al-Hussan, K.A.; Al-Suliman, K.M.; Wafa, N.F.

    1993-01-01

    Natural background radiation measurements have been made at numerous locations throughout the world. Little work in this field has been done in developing countries. In this study, the external exposure rates due to natural background radiation sources have been measured for different Saudi Arabian cities. Thermoluminescence dosimeters, CaF 2 Dy(TLD-200), has been used for field measurements. Exposure to TLD's response correlations were obtained for each TLD using a 137 Cs source. A correlation of TLD's response fading at a continuous radiation exposure environment was obtained and applied to correct field measurements. The measurements were taken every two months for a total of six intervals during the whole year. The average measurements of outdoor external exposure rates was found to vary between a minimum of 5.29 μR h -1 in Dammam city and a maximum of 11.59 μR h -1 in Al-Khamis city. (1 fig., 1 tab.)

  10. Flexicurity strategies on the economic crisis background

    Directory of Open Access Journals (Sweden)

    Daniela PAŞNICU

    2010-06-01

    Full Text Available • The flexicurity concept – a combination of flexibility and security strategies, specific to each country – is a successful outcome[1] of the 2010 Lisbon Strategy. Ever since 2000, this concept has been implemented for continuing the European labour markets reform. The conclusion of the Mission for Flexicurity[2] is that the European labour markets challenges have not changed, therefore flexicurity is the strategy to be further implemented in order to align to the new competition requirements, providing also the necessary social protection, especially on the current economic crisis background.   The paper addresses the flexicurity concept development, the implications of the flexicurity strategies and of the steps taken on the European Union Member States labour markets, on the economic crisis background.

  11. Partition function for a singular background

    Energy Technology Data Exchange (ETDEWEB)

    McKenzie-Smith, J.J. [Financial Risk Management Ltd, 15 Adam Street, London WC2N 6AH (United Kingdom)]. E-mail: julian.mckenzie-smith@frmhedge.com; Naylor, W. [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan)]. E-mail: naylor@yukawa.kyoto-u.ac.jp

    2005-03-17

    We present a method for evaluating the partition function in a varying external field. Specifically, we look at the case of a non-interacting, charged, massive scalar field at finite temperature with an associated chemical potential in the background of a delta-function potential. Whilst we present a general method, valid at all temperatures, we only give the result for the leading order term in the high temperature limit. Although the derivative expansion breaks down for inhomogeneous backgrounds we are able to obtain the high temperature expansion, as well as an analytic expression for the zero point energy, by way of a different approximation scheme, which we call the local Born approximation (LBA)

  12. Cosmic microwave background bispectrum from recombination.

    Science.gov (United States)

    Huang, Zhiqi; Vernizzi, Filippo

    2013-03-08

    We compute the cosmic microwave background temperature bispectrum generated by nonlinearities at recombination on all scales. We use CosmoLib2nd, a numerical Boltzmann code at second order to compute cosmic microwave background bispectra on the full sky. We consistently include all effects except gravitational lensing, which can be added to our result using standard methods. The bispectrum is peaked on squeezed triangles and agrees with the analytic approximation in the squeezed limit at the few percent level for all the scales where this is applicable. On smaller scales, we recover previous results on perturbed recombination. For cosmic-variance limited data to l(max)=2000, its signal-to-noise ratio is S/N=0.47, corresponding to f(NL)(eff)=-2.79, and will bias a local signal by f(NL)(loc) ~/= 0.82.

  13. Fluctuations in the cosmic microwave background

    International Nuclear Information System (INIS)

    Banday, A.J.; Wolfendale, A.W.

    1990-01-01

    In view of the importance to contemporary cosmology, and to our understanding of the Universe, of the precise nature of the Cosmic Microwave Background (CMB) spectrum, we consider the effects on this spectrum of contamination by other radiation fields of both galactic and extragalactic origin. Particular attention is given to the significance of measurements of the fluctuations in the 'background' radiation detected at 10.46 GHz and we conclude that these fluctuations are of the same magnitude as those expected from galactic cosmic-ray effects. A more detailed study of the cosmic-ray induced fluctuations and measurements at higher frequencies will be needed before genuine CMB fluctuations can be claimed. (author)

  14. A Detector for Cosmic Microwave Background Polarimetry

    Science.gov (United States)

    Wollack, E.; Cao, N.; Chuss, D.; Hsieh, W.-T.; Moseley, S. Harvey; Stevenson, T.; U-yen, K.

    2008-01-01

    We present preliminary design and development work on polarized detectors intended to enable Cosmic Microwave Background polarization measurements that will probe the first moments of the universe. The ultimate measurement will be challenging, requiring background-limited detectors and good control of systematic errors. Toward this end, we are integrating the beam control of HE-11 feedhorns with the sensitivity of transition-edge sensors. The coupling between these two devices is achieved via waveguide probe antennas and superconducting microstrip lines. This implementation allows band-pass filters to be incorporated on the detector chip. We believe that a large collection of single-mode polarized detectors will eventually be required for the reliable detection of the weak polarized signature that is expected to result from gravitational waves produced by cosmic inflation. This focal plane prototype is an important step along the path to this detection, resulting in a capability that will enable various future high performance instrument concepts.

  15. Family Background and Educational Success in Denmark

    DEFF Research Database (Denmark)

    D. Munk, Martin; McIntoch, James

    This research examines the role of family background variables in the determination of educational attainment in Denmark. A categorical representation of the highest level of education attained is the dependent variable. It is analyzed by procedures which take account of the presence of unobserva...... procedures are in the spirit of the work of Cameron and Heckman (1998), but are more general. Econometric issues and the results of what other Scandinavian researchers in this area have found are also discussed in section 4....

  16. Durability 2007. Injection grout investigations. Background description

    International Nuclear Information System (INIS)

    Orantie, K.; Kuosa, H.

    2008-12-01

    The aim of this project was to evaluate the durability risks of injection grouts. The investigations were done with respect to the application conditions, materials and service life requirements at the ONKALO underground research facility. The study encompassed injection grout mixtures made of ultrafine cement with and without silica fume. Some of the mixtures hade a low pH and thus a high silica fume content. The project includes a background description on durability literature, laboratory testing programme, detailed analysis of results and recommendations for selecting of ideal grout mixtures. The background description was made for the experimental study of low-pH and reference rock injection grouts as regards pore- and microstructure, strength, shrinkage/swelling and thus versatile durability properties. A summary of test methods is presented as well as examples, i.e. literature information or former test results, of expected range of results from the tests. Also background information about how the test results correlate to other material properties and mix designs is presented. Besides the report provides basic information on the pore structure of cement based materials. Also the correlation between the pore structure of cement based materials and permeability is shortly discussed. The test methods included in the background description are compressive strength, measurement of bulk drying, autogenous and chemical shrinkage and swelling, hydraulic conductivity / permeability, capillary water uptake test, mercury intrusion porosimetry (MIP) and thin section analysis. Three main mixtures with water-binder ratio of 0.8, 1.0 and 1.4 and silica fume content of 0, 15 and 40% were studied in the laboratory. Besides two extra mixtures were studied to provide additional information about the effect of varying water-dry-material ratio and silica fume content on durability. The evaluation of water tightness based on water permeability coefficient and micro cracking was

  17. Apparatus for reducing solvent luminescence background emissions

    Energy Technology Data Exchange (ETDEWEB)

    Affleck, Rhett L. (Los Alamos, NM); Ambrose, W. Patrick (Los Alamos, NM); Demas, James N. (Charlottesville, VA); Goodwin, Peter M. (Jemez Springs, NM); Johnson, Mitchell E. (Pittsburgh, PA); Keller, Richard A. (Los Alamos, NM); Petty, Jeffrey T. (Los Alamos, NM); Schecker, Jay A. (Sante Fe, NM); Wu, Ming (Los Alamos, NM)

    1998-01-01

    The detectability of luminescent molecules in solution is enhanced by reducing the background luminescence due to impurity species also present in the solution. A light source that illuminates the solution acts to photolyze the impurities so that the impurities do not luminesce in the fluorescence band of the molecule of interest. Molecules of interest may be carried through the photolysis region in the solution or may be introduced into the solution after the photolysis region.

  18. Radiocarbon accelerator mass spectrometry: background and contamination

    International Nuclear Information System (INIS)

    Beukens, R.P.

    1993-01-01

    Since the advent of radiocarbon accelerator mass spectrometry (AMS) many studies have been conducted to understand the background from mass spectrometric processes and the origins of contamination associated with the ion source and sample preparation. By studying the individual contributions a better understanding of these processes has been obtained and it has been demonstrated that it is possible to date samples reliably up to 60 000 BP. (orig.)

  19. MEGA: A Low-Background Radiation Detector

    International Nuclear Information System (INIS)

    Kazkaz, Kareem; Aalseth, Craig E.; Hossbach, Todd W.; Gehman, Victor M.; Kephart, Jeremy; Miley, Harry S.

    2004-01-01

    The multiple-element gamma assay (MEGA) is a low-background detector designed to support environmental monitoring and national security applications. MEGA also demonstrates technology needed or Majorana, a next generation neutrino mass experiment. It will also exploit multicoincidence signatures to identify specific radioactive isotopes. MEGA is expected to begin testing in late 2003 for eventual installation at the Waste Isolation Plant, Carlsbad, NM

  20. Charge generation in an oscillating background

    International Nuclear Information System (INIS)

    Funakubo, Koichi; Kakuto, Akira; Otsuki, Shoichiro; Toyoda, Fumihiko

    2001-01-01

    Preheating after inflation, which can be interpreted as particle creation in an oscillating inflation background, represents a state far from thermal equilibrium. We extend the field theoretical treatment of the preheating by Linde et al. to the case of multicomponent complex scalars to show that charges are created in this process if C and CP are violated. A new possibility for baryogenesis based on this mechanism is also discussed. (author)

  1. Charge generation in an oscillating background

    Energy Technology Data Exchange (ETDEWEB)

    Funakubo, Koichi [Department of Physics, Saga Univ., Saga (Japan); Kakuto, Akira; Otsuki, Shoichiro; Toyoda, Fumihiko [Kyushu School of Engineering, Kinki Univ., Iizuka, Fukuoka (Japan)

    2001-05-01

    Preheating after inflation, which can be interpreted as particle creation in an oscillating inflation background, represents a state far from thermal equilibrium. We extend the field theoretical treatment of the preheating by Linde et al. to the case of multicomponent complex scalars to show that charges are created in this process if C and CP are violated. A new possibility for baryogenesis based on this mechanism is also discussed. (author)

  2. Anisotropy of the cosmic background radiation

    International Nuclear Information System (INIS)

    Silk, J.

    1988-01-01

    The characteristics of the cosmic microwave background radiation (CBR) are reviewed, focusing on intrinsic anisotropies caused by primordial matter fluctuations. The basic elements of the CBR are outlined and the contributions to anisotropy at different angular scales are discussed. Possible fluctuation spectra that can generate the observed large-scale structure of the universe through gravitational instability and nonlinear evolution are examined and compared with observational searches for cosmic microwave anisotropies. 21 refs

  3. Distortion of the microwave background by dust

    International Nuclear Information System (INIS)

    Rowan-Robinson, M.

    1981-01-01

    The Woody and Richards distortion of the microwave background has a natural explanation within the framework of the isothermal density fluctuation picture. A pregalactic generation of ''stars'' makes light and metals. The latter are able to condense into dust grains at a redshift approximately 150-225, which then absorb the starlight and reradiate it in the infrared. At the present epoch we see this emission redshifted into the millimetre range of the spectrum

  4. Qatar: Background and U.S. Relations

    Science.gov (United States)

    2012-06-06

    Science Monitor, February 6, 2007. 10 For example, Senator John Kerry voiced specific concerns about alleged Qatari government and private support...Sen. Kerry Speaks on Middle East to Brookings Institute,” April 2, 2009. Qatar: Background and U.S. Relations Congressional Research Service 6...alcohol, which is available in licensed premises such as the bars of major hotels and clubs. 53 U.S

  5. Egypt: Background and U.S. Relations

    Science.gov (United States)

    2009-05-12

    contributions from Germany , Japan, and Switzerland. For more information on the MFO, see http://www.mfo.org/Default.asp?bhcp=1. Egypt: Background and...2008 Report, Egypt’s pace of business reforms and deregulation between 2006 and 2007 ranked first worldwide. In recent years, the state has...reinvigorated its privatization program by divesting shares in the state-dominated banking and insurance sectors. Additionally, the government removed import

  6. Duality invariant class of exact string backgrounds

    CERN Document Server

    Klimcík, C

    1994-01-01

    We consider a class of $2+D$ - dimensional string backgrounds with a target space metric having a covariantly constant null Killing vector and flat `transverse' part. The corresponding sigma models are invariant under $D$ abelian isometries and are transformed by $O(D,D)$ duality into models belonging to the same class. The leading-order solutions of the conformal invariance equations (metric, antisymmetric tensor and dilaton), as well as the action of $O(D,D)$ duality transformations on them, are exact, i.e. are not modified by $\\a'$-corrections. This makes a discussion of different space-time representations of the same string solution (related by $O(D,D|Z)$ duality subgroup) rather explicit. We show that the $O(D,D)$ duality may connect curved $2+D$-dimensional backgrounds with solutions having flat metric but, in general, non-trivial antisymmetric tensor and dilaton. We discuss several particular examples including the $2+D=4$ - dimensional background that was recently interpreted in terms of a WZW model.

  7. Cosmic Infrared Background Fluctuations and Zodiacal Light

    Science.gov (United States)

    Arendt, Richard G.; Kashlinsky, A.; Moseley, S. H.; Mather, J.

    2016-06-01

    We performed a specific observational test to measure the effect that the zodiacal light can have on measurements of the spatial fluctuations of the near-IR background. Previous estimates of possible fluctuations caused by zodiacal light have often been extrapolated from observations of the thermal emission at longer wavelengths and low angular resolution or from IRAC observations of high-latitude fields where zodiacal light is faint and not strongly varying with time. The new observations analyzed here target the COSMOS field at low ecliptic latitude where the zodiacal light intensity varies by factors of ˜2 over the range of solar elongations at which the field can be observed. We find that the white-noise component of the spatial power spectrum of the background is correlated with the modeled zodiacal light intensity. Roughly half of the measured white noise is correlated with the zodiacal light, but a more detailed interpretation of the white noise is hampered by systematic uncertainties that are evident in the zodiacal light model. At large angular scales (≳100″) where excess power above the white noise is observed, we find no correlation of the power with the modeled intensity of the zodiacal light. This test clearly indicates that the large-scale power in the infrared background is not being caused by the zodiacal light.

  8. Background Selection in Partially Selfing Populations

    Science.gov (United States)

    Roze, Denis

    2016-01-01

    Self-fertilizing species often present lower levels of neutral polymorphism than their outcrossing relatives. Indeed, selfing automatically increases the rate of coalescence per generation, but also enhances the effects of background selection and genetic hitchhiking by reducing the efficiency of recombination. Approximations for the effect of background selection in partially selfing populations have been derived previously, assuming tight linkage between deleterious alleles and neutral loci. However, loosely linked deleterious mutations may have important effects on neutral diversity in highly selfing populations. In this article, I use a general method based on multilocus population genetics theory to express the effect of a deleterious allele on diversity at a linked neutral locus in terms of moments of genetic associations between loci. Expressions for these genetic moments at equilibrium are then computed for arbitrary rates of selfing and recombination. An extrapolation of the results to the case where deleterious alleles segregate at multiple loci is checked using individual-based simulations. At high selfing rates, the tight linkage approximation underestimates the effect of background selection in genomes with moderate to high map length; however, another simple approximation can be obtained for this situation and provides accurate predictions as long as the deleterious mutation rate is not too high. PMID:27075726

  9. A background free double beta decay experiment

    International Nuclear Information System (INIS)

    Giomataris, I

    2011-01-01

    We present a new detection scheme for rejecting backgrounds in neutrino-less double beta decay experiments. It relies on the detection of Cherenkov light emitted by electrons in the MeV region. The momentum threshold is tuned to reach a good discrimination between background and good events. We consider many detector concepts and a range of target materials. The most promising is the high-pressure 136 Xe emitter where the required energy threshold is easily adjusted. Combination of this concept and a high pressure Time Projection Chamber could provide an optimal solution. A simple and low cost effective solution is the use of the Spherical Proportional Counter that provides, using a single read-out channel, two delayed signals from ionization and Cherenkov light. In solid-state double beta decay emitters, because of its higher density, the considered process is out of energy range. An escape will be the fabrication of double decay emitters having lower density by using for instance the aerogel technique. It is surprising that a technology used for particle identification in high-energy physics becomes a powerful tool for rejecting backgrounds in such low-energy experiments.

  10. Heterotic string in an arbitrary background field

    International Nuclear Information System (INIS)

    Sen, A.

    1985-01-01

    An expression for the light-cone gauge action for the first-quantized heterotic string in the presence of arbitrary background gauge, gravitational, and antisymmetric tensor fields is derived. The result is a two-dimensional local field theory with N = 1/2 supersymmetry. The constraints imposed on the background fields in order to make this theory one-loop finite are derived. These constraints are identical to the equations of motion for the massless fields at the linearized level. Finally, it is shown that if there is no background antisymmetric tensor field, and if the gauge connection is set equal to the spin connection, the effective action is that of an N = 1 supersymmetric nonlinear and N = 2 supersymmetric Georgi-Glashow models the occurrence of the fermion fractionization is the necessity; the ignorance of it results in the inconsistency in the perturbative calculation of the mass splittings among the members of the supermultiplets. The notable feature of our result is that the degeneracy due to the Jackiw-Rebbi zero mode is not independent of the one required by the supersymmetry, suggesting a nontrivial structure in embedding the topology of Higgs fields into supersymmetric gauge theories

  11. Using Correlated Photons to Suppress Background Noise

    Science.gov (United States)

    Jackson, Deborah; Hockney, George; Dowling, Jonathan

    2003-01-01

    A proposed method of suppressing the effect of background noise in an optical communication system would exploit the transmission and reception of correlated photons at the receiver. The method would not afford any advantage in a system in which performance is limited by shot noise. However, if the performance of the system is limited by background noise (e.g., sunlight in the case of a free-space optical communication system or incoherently scattered in-band photons in the case of a fiber-optic communication system), then the proposed method could offer an advantage: the proposed method would make it possible to achieve a signal-to-noise ratio (S/N) significantly greater than that of an otherwise equivalent background- noise-limited optical communication system based on the classical transmission and reception of uncorrelated photons. The figure schematically depicts a classical optical-communication system and a system according to the proposed method. In the classical system, a modulated laser beam is transmitted along an optical path to a receiver, the optics of which include a narrow-band-pass filter that suppresses some of the background noise. A photodetector in the receiver detects the laser-beam and background photons, most or all of which are uncorrelated. In the proposed system, correlated photons would be generated at the transmitter by making a modulated laser beam pass through a nonlinear parametric down-conversion crystal. The sum of frequencies of the correlated photons in each pair would equal the frequency of the incident photon from which they were generated. As in the classical system, the correlated photons would travel along an optical path to a receiver, where they would be band-pass filtered and detected. Unlike in the classical system, the photodetector in the receiver in this system would be one that intrinsically favors the detection of pairs of correlated photons over the detection of uncorrelated photons. Even though there would be no

  12. Annual radiation background in Isfahan city

    International Nuclear Information System (INIS)

    Tavakoli, Mohammad B.

    2002-01-01

    Measurement of environmental exposure is very important from different points of view. It is especially important for human health. It has been measured accurately in many countries. In Iran, it is also measured in some cities especially in high background areas such as Ramsar, but there is not any measurement in Isfahan. Measurement of background radiation in this study is performed using TLD method. The TLDs used are made from CaSO 4 :Dy, which is very sensitive. The locations under investigations in this research were 52 health centers distributed all around Isfahan city. Each TLD badge was put in a special plastic bag and left over the roofs of the selected health center for a month. The procedure was repeated for all 12 months of the year 1379(21 st March 2000 to 20 th March 2001). The results were used to obtain mean and SD in each month and at different places. The maximum and the minimum of obtained results for dose equivalent in different months and locations were 15.9x10 -2 and 6.5x10 -2 mSv. Obtained maximum and minimum of the means between all the locations were 10.5x10 -2 and 8.6x10 2 mSv for the whole year. Monthly mean and SD for Isfahan city for the whole year were 9.7x10 -2 and 1.5x10 -2 respectively therefore mean annual dose equivalent in Isfahan city is 1.16mSv. The results do not show any high background radiation area

  13. The background is remapped across saccades.

    Science.gov (United States)

    Cha, Oakyoon; Chong, Sang Chul

    2014-02-01

    Physiological studies have found that neurons prepare for impending eye movements, showing anticipatory responses to stimuli presented at the location of the post-saccadic receptive fields (RFs) (Wurtz in Vis Res 48:2070-2089, 2008). These studies proposed that visual neurons with shifting RFs prepared for the stimuli they would process after an impending saccade. Additionally, psychophysical studies have shown behavioral consequences of those anticipatory responses, including the transfer of aftereffects (Melcher in Nat Neurosci 10:903-907, 2007) and the remapping of attention (Rolfs et al. in Nat Neurosci 14:252-258, 2011). As the physiological studies proposed, the shifting RF mechanism explains the transfer of aftereffects. Recently, a new mechanism based on activation transfer via a saliency map was proposed, which accounted for the remapping of attention (Cavanagh et al. in Trends Cogn Sci 14:147-153, 2010). We hypothesized that there would be different aspects of the remapping corresponding to these different neural mechanisms. This study found that the information in the background was remapped to a similar extent as the figure, provided that the visual context remained stable. We manipulated the status of the figure and the ground in the saliency map and showed that the manipulation modulated the remapping of the figure and the ground in different ways. These results suggest that the visual system has an ability to remap the background as well as the figure, but lacks the ability to modulate the remapping of the background based on the visual context, and that different neural mechanisms might work together to maintain visual stability across saccades.

  14. Charged Hadron Properties in Background Electric Fields

    International Nuclear Information System (INIS)

    Detmold, William; Tiburzi, Brian C.; Walker-Loud, Andre

    2010-01-01

    We report on a lattice calculation demonstrating a novel new method to extract the electric polarizability of charged pseudo-scalar mesons by analyzing two point correlation functions computed in classical background electric fields. A staple component of any electrodynamics or quantum mechanics course is the electric polarizability. Neutral material immersed in a weak external field polarizes, internally setting up an electric dipole moment, aligned so as to minimize the energy. At the atomic level, the electron clouds are distorted creating these microscopic dipole moments. The same process occurs at the hadronic level but the polarization effects are now constrained by the strong force. Polarizabilities of these bound QCD states can be viewed as a distortion of the charged pion cloud of a given hadron. One can use lattice QCD to non-perturbatively compute the quark and gluon interactions in the presence of background electric (or magnetic) fields. For sufficiently weak background fields, the low energy properties of the hadrons can be rigorously computed using effective field theory. With this treatment, a picture of hadrons emerges from chiral dynamics: that of a hadronic core surrounded by a pseudoscalar meson cloud. As some pseudoscalar mesons are charged, polarizabilities of hadrons encode the stiffness of the charged meson cloud (as well as that of the core). The form of pseudoscalar meson polarizabilities is consequently strongly constrained by chiral dynamics. However, beyond the leading order, the results depend upon essentially unknown low-energy constants, which must currently be estimated in a model-dependent fashion. In the case of the charged pion, the experimental measurement of the polarizability has proven difficult, both in the original measurement as well as the most recent published result. Currently, there is a 2-3 sigma discrepancy between the two-loop cPT prediction and the measured charged pion polarizability. New results with higher

  15. Teaching in Multicultural Background in the States

    Institute of Scientific and Technical Information of China (English)

    潘若芸

    2010-01-01

    The diversity present in every aspect of American life is an inevitable consequence of its multicultural society.Schools across the country are a reflection of what is,and always has been,an ever changing demographic constitution.Classroom teachers,especially teachers who have no teaching experience in the country,face a stiff challenge of teaching all students,regardless of their backgrounds.As a Chinese guest teacher in the States,I learned that the"growing-up"of a teacher requires positive changes in three areas:knowledge,attitudes and skills.Support from administrators is also vital in the"growing-up"process.

  16. Emergence of oscillons in an expanding background

    International Nuclear Information System (INIS)

    Farhi, E.; Guth, A. H.; Iqbal, N.; Graham, N.; Rosales, R. R.; Stamatopoulos, N.

    2008-01-01

    We consider a (1+1) dimensional scalar field theory that supports oscillons, which are localized, oscillatory, stable solutions to nonlinear equations of motion. We study this theory in an expanding background and show that oscillons now lose energy, but at a rate that is exponentially small when the expansion rate is slow. We also show numerically that a universe that starts with (almost) thermal initial conditions will cool to a final state where a significant fraction of the energy of the universe--on the order of 50%--is stored in oscillons. If this phenomenon persists in realistic models, oscillons may have cosmological consequences.

  17. Quantum treatment of neutrino in background matter

    International Nuclear Information System (INIS)

    Studenikin, A I

    2006-01-01

    Motivated by the need of elaboration of the quantum theory of the spin light of neutrino in matter (SLν), we have studied in more detail the exact solutions of the Dirac equation for neutrinos moving in background matter. These exact neutrino wavefunctions form a basis for a rather powerful method of investigation of different neutrino processes in matter, which is similar to the Furry representation of quantum electrodynamics in external fields. Within this method we also derive the corresponding Dirac equation for an electron moving in matter and consider the electromagnetic radiation ('spin light of electron in matter' (SLe)) that can be emitted by the electron in this case

  18. Detecting the Stochastic Gravitational-Wave Background

    Science.gov (United States)

    Colacino, Carlo Nicola

    2017-12-01

    The stochastic gravitational-wave background (SGWB) is by far the most difficult source of gravitational radiation detect. At the same time, it is the most interesting and intriguing one. This book describes the initial detection of the SGWB and describes the underlying mathematics behind one of the most amazing discoveries of the 21st century. On the experimental side it would mean that interferometric gravitational wave detectors work even better than expected. On the observational side, such a detection could give us information about the very early Universe, information that could not be obtained otherwise. Even negative results and improved upper bounds could put constraints on many cosmological and particle physics models.

  19. Renormalization using the background-field method

    International Nuclear Information System (INIS)

    Ichinose, S.; Omote, M.

    1982-01-01

    Renormalization using the background-field method is examined in detail. The subtraction mechanism of subdivergences is described with reference to multi-loop diagrams and one- and two-loop counter-term formulae are explicitly given. The original one-loop counter-term formula of 't Hooft is thereby improved. The present method of renormalization is far easier to manage than the usual one owing to the fact only gauge-invariant quantities are to be considered when worked in an appropriate gauge. Gravity and Yang-Mills theories are studied as examples. (orig.)

  20. Background of the Degree in Public Accounting

    Directory of Open Access Journals (Sweden)

    José G. Vargas-Hernández

    2012-08-01

    Full Text Available This paper aims to review public accountant education in terms of the interrelated subjects as well as its background. The results of this education development project improve the formation of the accountant public education because of its linkage between teachers and students in the research process and the design of new teaching strategies that contribute to solving real problems and facilitate the social projection. The academic administration is characterized by processes that arise and is generated within the same individuals, focused on the construction and reconstruction of knowledge, proper training and formation of builders of their own processes.

  1. Beam-gas background calculation for DEAR

    International Nuclear Information System (INIS)

    Guiducci, S.

    1997-01-01

    The present paper describes the results obtained from a Monte Carlo simulation of the particles lost in the DAY-ONE Interaction Region (IR) of the DAFNE machine. Coulomb scattering on the nuclei of residual gas and beam-gas Bremsstrahlung, which are the main sources of background in the initial phase of machine operation, were considered. A ray-tracking program (TURTLE) was used to follow the trajectories of the particles in the rings and to evaluate the number of particles that hit the vacuum chamber in the interaction region

  2. Signatures of a hidden cosmic microwave background.

    Science.gov (United States)

    Jaeckel, Joerg; Redondo, Javier; Ringwald, Andreas

    2008-09-26

    If there is a light Abelian gauge boson gamma' in the hidden sector its kinetic mixing with the photon can produce a hidden cosmic microwave background (HCMB). For meV masses, resonant oscillations gammagamma' happen after big bang nucleosynthesis (BBN) but before CMB decoupling, increasing the effective number of neutrinos Nnu(eff) and the baryon to photon ratio, and distorting the CMB blackbody spectrum. The agreement between BBN and CMB data provides new constraints. However, including Lyman-alpha data, Nnu(eff) > 3 is preferred. It is tempting to attribute this effect to the HCMB. The interesting parameter range will be tested in upcoming laboratory experiments.

  3. WMO background air pollution monitoring network (BAPMON)

    Energy Technology Data Exchange (ETDEWEB)

    Koehler, A

    1980-01-01

    The objectives of the network include the establishment of baseline measurements of the global troposphere against which subsequent changes can be measured. The minimum program includes analysis of wet precipitation, observation of the aerosol optical depth, and sampling of suspended particulates. Standardization efforts have resulted in accuracies in rainwater samples to within 10%. Pollutant levels are shown for regional, urban and continental stations. The possibility of establishing median values for different modes of operation at a station (background and nonbackground mode) is examined. The interference of water vapor with CO/sub 2/ measurements is discussed.

  4. Learning Physics from the Cosmic Microwave Background

    CERN Document Server

    Ellis, Jonathan Richard

    1999-01-01

    The Cosmic Microwave Background (CMB) provides a precious window on fundamental physics at very high energy scales, possibly including quantum gravity, GUTs and supersymmetry. The CMB has already enabled defect-based rivals to inflation to be discarded, and will be able to falsify many inflationary models. In combination with other cosmological observations, including those of high-redshift supernovae and large-scale structure, the CMB is on the way to providing a detailed budget for the density of the Universe, to be compared with particle-physics calculations for neutrinos and cold dark matter. Thus CMB measurements complement experiments with the LHC and long-baseline neutrino beams.

  5. JOURNALISM STUDIES IN ARGENTINA: BACKGROUND AND QUESTIONS

    Directory of Open Access Journals (Sweden)

    Adriana Amado

    2014-06-01

    Full Text Available This article summarizes the background of empirical journalism studies in Argentina.  In recent publications, researchers have consistently underscored the lack of data on the profession and the scarce development of theoretical frameworks related to journalism studies.  The local investigations have prioritized approaches and methods that do not give the whole picture of the population of journalists. Most of the research tends to equate media analysis and media messages with journalism study and keeps on failing to provide data that allows for learning about the working conditions and the professional profile of the Argentinean journalists.

  6. Canonical differential geometry of string backgrounds

    International Nuclear Information System (INIS)

    Schuller, Frederic P.; Wohlfarth, Mattias N.R.

    2006-01-01

    String backgrounds and D-branes do not possess the structure of Lorentzian manifolds, but that of manifolds with area metric. Area metric geometry is a true generalization of metric geometry, which in particular may accommodate a B-field. While an area metric does not determine a connection, we identify the appropriate differential geometric structure which is of relevance for the minimal surface equation in such a generalized geometry. In particular the notion of a derivative action of areas on areas emerges naturally. Area metric geometry provides new tools in differential geometry, which promise to play a role in the description of gravitational dynamics on D-branes

  7. Science with Future Cosmic Microwave Background Observations

    Energy Technology Data Exchange (ETDEWEB)

    Bernardis, P. de; Calvo, M.; Giordano, C.; Masi, S.; Nati, F.; Piacentini, F.; Schillaci, A. [Dipartimento di Fisica, Universita di Roma La Sapienza, P.le A. Moro 2, 00185 Roma (Italy)

    2009-10-15

    After the successful measurements of many ground based, balloon-borne and satellite experiments, which started the era of 'Precision Cosmology', Cosmic Microwave Background (CMB) observations are now focusing on two targets: the precision measurement of B-modes in the polarization field, and the measurement of the Sunyaev-Zeldovich effect in distant clusters of galaxies. Polarization measurements represent the best way to probe the very early universe, and the energy scale of inflation. Fine-scale anisotropy measurements, possibly with spectral capabilities, can provide important information on dark matter and dark energy. Here we describe original approaches to these measurements.

  8. Science with Future Cosmic Microwave Background Observations

    International Nuclear Information System (INIS)

    Bernardis, P. de; Calvo, M.; Giordano, C.; Masi, S.; Nati, F.; Piacentini, F.; Schillaci, A.

    2009-01-01

    After the successful measurements of many ground based, balloon-borne and satellite experiments, which started the era of 'Precision Cosmology', Cosmic Microwave Background (CMB) observations are now focusing on two targets: the precision measurement of B-modes in the polarization field, and the measurement of the Sunyaev-Zeldovich effect in distant clusters of galaxies. Polarization measurements represent the best way to probe the very early universe, and the energy scale of inflation. Fine-scale anisotropy measurements, possibly with spectral capabilities, can provide important information on dark matter and dark energy. Here we describe original approaches to these measurements.

  9. Moduli stabilization in non-geometric backgrounds

    International Nuclear Information System (INIS)

    Becker, Katrin; Becker, Melanie; Vafa, Cumrun; Walcher, Johannes

    2007-01-01

    Type II orientifolds based on Landau-Ginzburg models are used to describe moduli stabilization for flux compactifications of type II theories from the world-sheet CFT point of view. We show that for certain types of type IIB orientifolds which have no Kaehler moduli and are therefore intrinsically non-geometric, all moduli can be explicitly stabilized in terms of fluxes. The resulting four-dimensional theories can describe Minkowski as well as anti-de Sitter vacua. This construction provides the first string vacuum with all moduli frozen and leading to a 4D Minkowski background

  10. Occupational doses due to photoneutrons in medical linear accelerators rooms

    International Nuclear Information System (INIS)

    Soares, Alessandro Facure Neves de Salles

    2006-04-01

    Medical linear accelerators, with maximum photon energies above 10 MeV, are becoming of common use in Brazil. Although desirable in the therapeutic point of view, the increase in photon energies causes the generation of undesired neutrons, which are produced through nuclear reactions between photons and the high Z target nuclei of the materials that constitute the accelerator head. In this work, MCNP simulation was undertaken to examine the neutron equivalent doses around the accelerators head and at the entrance of medical linear accelerators treatment rooms, some of them licensed in Brazil by the National Regulatory Agency (CNEN). The simulated neutron dose equivalents varied between 2 e 26 μ Sv/Gy RX , and the results were compared with calculations performed with the use of some semi-empirical equations found in literature. It was found that the semi-empirical equations underestimate the simulated neutron doses in the majority of the cases, if compared to the simulated values, suggesting that these equations must be revised, due to the increasing number of high energy machines in the country. (author)

  11. Photon and photoneutron spectra produced in radiotherapy Linacs

    International Nuclear Information System (INIS)

    Vega C, H. R.; Martinez O, S. A.; Benites R, J. L.; Lallena, A. M.

    2011-10-01

    A Monte Carlo calculation, using the MCNPX code, was carried out in order to estimate the photon and neutron spectra in two locations of two linacs operating at 15 and 18 MV. Detailed models of both linac heads were used in the calculations. Spectra were estimated below the flattening filter and at the isocenter. Neutron spectra show two components due to evaporation and knock-on neutrons. Lethargy spectra under the filter were compared to the spectra calculated from the function quoted by Tosi et al. that describes reasonably well neutron spectra beyond 1 MeV, though tends to underestimate the energy region between 10 -6 and 1 MeV. Neutron and Bremsstrahlung spectra show the same features regardless of the linac voltage. The amount of photons and neutrons produced by the 15 MV linac is smaller than that found for the 18 MV linac. As expected, Bremsstrahlung spectra ends according to the voltage used to accelerate the electrons. (Author)

  12. Photoneutron cross sections for D2O and beryllium

    International Nuclear Information System (INIS)

    Bowsher, H.F.; Woods, F.J.; Baumann, N.P.

    1975-01-01

    The photodissociation cross section by 24 Na gamma rays was measured for deuterium in order to resolve a discrepancy between earlier measurements (1.43 to 1.59 millibarns) and a more recently reported one (1.34 mb). The measurement of the beryllium (γ,n) cross section for 24 Na gamma rays was also included as a check. Results for deuterium (1.54 mb) are in agreement with the earlier values

  13. Angular distributions of threshold photoneutrons from 208Pb

    International Nuclear Information System (INIS)

    Haacke, L.C.

    1973-01-01

    The shape of the 41 keV resonance in the 208 Pb(γ,n) 207 Pb reaction has been considered in some detail in view of recent reports of asymmetry interpreted in terms of interference between resonant and nonresonant neutron capture amplitudes. Additional threshold measurements were made using bremsstrahlung with an endpoint energy of 8.0 MeV. It has been concluded that asymmetry in the present data appears to be induced by the presence of an unresolved resonance, and that this interpretation of the resonance shape cannot be confuted on the basis of (n,γ) or total neutron cross section measurements made elsewhere. (author)

  14. Measurement of photoneutron spectrum at Pohang Neutron Facility

    Energy Technology Data Exchange (ETDEWEB)

    Kim, G.N.; Kovalchuk, V.; Lee, Y.S.; Skoy, V.; Cho, M.H.; Ko, I.S.; Namkung, W. [POSTECH, Pohang Accelerator Laboratory, Pohang, Kyungbuk (Korea)

    2001-03-01

    Pohang Neutron Facility, which is the pulsed neutron facility based on the 100-MeV electron linear accelerator, was constructed for nuclear data production in Korea. The Pohang Neutron Facility consists of an electron linear accelerator, a water-cooled Ta target with a water moderator and a time-of-flight path with an 11 m length. The neutron energy spectra are measured for different water levels inside the moderator and compared with the MCNP calculation. The optimum size of the water moderator is determined on the base of this result. The time dependent spectra of neutrons in the water moderator are investigated with the MCNP calculation. (author)

  15. Photon and photoneutron spectra produced in radiotherapy Linacs

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Martinez O, S. A. [Universidad Pedagogica y Tecnologica de Colombia, Grupo de Fisica Nuclear Aplicada y Simulacion, Av. Central del Norte Km. 1, Via Paipa Tunja, Boyaca (Colombia); Benites R, J. L. [Universidad Autonoma de Nayarit, Postgrado CBAP, Carretera Tepic Compostela Km. 9, Xalisco, Nayarit (Mexico); Lallena, A. M., E-mail: fermineutron@yahoo.com [Universida de Granada, Departamento de Fisica Atomica, Molecular y Nuclear, E-18071 Granada (Spain)

    2011-10-15

    A Monte Carlo calculation, using the MCNPX code, was carried out in order to estimate the photon and neutron spectra in two locations of two linacs operating at 15 and 18 MV. Detailed models of both linac heads were used in the calculations. Spectra were estimated below the flattening filter and at the isocenter. Neutron spectra show two components due to evaporation and knock-on neutrons. Lethargy spectra under the filter were compared to the spectra calculated from the function quoted by Tosi et al. that describes reasonably well neutron spectra beyond 1 MeV, though tends to underestimate the energy region between 10{sup -6} and 1 MeV. Neutron and Bremsstrahlung spectra show the same features regardless of the linac voltage. The amount of photons and neutrons produced by the 15 MV linac is smaller than that found for the 18 MV linac. As expected, Bremsstrahlung spectra ends according to the voltage used to accelerate the electrons. (Author)

  16. Photoneutron and Photonuclear Cross Sections According to Packed cluster Model

    International Nuclear Information System (INIS)

    El-Mekkawi, L.S.; El-Bakty, O.M.

    1998-01-01

    Photonuclear gross sections have been estimated for 232 Th, 237 Np, 239 Pu, 233 U, 234 U, 235 U, 238 U in the energy range from threshold up to 20 MeV, by perturbation balance in Packed Cluster. The Packed Cluster (gamma, f) and (gamma, n) cross sections require complete absence of any (gamma,2n) or (gamma,nf) cross sections for 233 U and 234 U as in experiment. It also explains the early (gamma,n) and gamma,nf) reactions in 235 U

  17. Chameleon scalar fields in relativistic gravitational backgrounds

    International Nuclear Information System (INIS)

    Tsujikawa, Shinji; Tamaki, Takashi; Tavakol, Reza

    2009-01-01

    We study the field profile of a scalar field φ that couples to a matter fluid (dubbed a chameleon field) in the relativistic gravitational background of a spherically symmetric spacetime. Employing a linear expansion in terms of the gravitational potential Φ c at the surface of a compact object with a constant density, we derive the thin-shell field profile both inside and outside the object, as well as the resulting effective coupling with matter, analytically. We also carry out numerical simulations for the class of inverse power-law potentials V(φ) = M 4+n φ −n by employing the information provided by our analytical solutions to set the boundary conditions around the centre of the object and show that thin-shell solutions in fact exist if the gravitational potential Φ c is smaller than 0.3, which marginally covers the case of neutron stars. Thus the chameleon mechanism is present in the relativistic gravitational backgrounds, capable of reducing the effective coupling. Since thin-shell solutions are sensitive to the choice of boundary conditions, our analytic field profile is very helpful to provide appropriate boundary conditions for Φ c ∼< O(0.1)

  18. Background Characterization Techniques For Pattern Recognition Applications

    Science.gov (United States)

    Noah, Meg A.; Noah, Paul V.; Schroeder, John W.; Kessler, Bernard V.; Chernick, Julian A.

    1989-08-01

    The Department of Defense has a requirement to investigate technologies for the detection of air and ground vehicles in a clutter environment. The use of autonomous systems using infrared, visible, and millimeter wave detectors has the potential to meet DOD's needs. In general, however, the hard-ware technology (large detector arrays with high sensitivity) has outpaced the development of processing techniques and software. In a complex background scene the "problem" is as much one of clutter rejection as it is target detection. The work described in this paper has investigated a new, and innovative, methodology for background clutter characterization, target detection and target identification. The approach uses multivariate statistical analysis to evaluate a set of image metrics applied to infrared cloud imagery and terrain clutter scenes. The techniques are applied to two distinct problems: the characterization of atmospheric water vapor cloud scenes for the Navy's Infrared Search and Track (IRST) applications to support the Infrared Modeling Measurement and Analysis Program (IRAMMP); and the detection of ground vehicles for the Army's Autonomous Homing Munitions (AHM) problems. This work was sponsored under two separate Small Business Innovative Research (SBIR) programs by the Naval Surface Warfare Center (NSWC), White Oak MD, and the Army Material Systems Analysis Activity at Aberdeen Proving Ground MD. The software described in this paper will be available from the respective contract technical representatives.

  19. Chameleon scalar fields in relativistic gravitational backgrounds

    Energy Technology Data Exchange (ETDEWEB)

    Tsujikawa, Shinji [Department of Physics, Faculty of Science, Tokyo University of Science, 1-3, Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan); Tamaki, Takashi [Department of Physics, Waseda University, Okubo 3-4-1, Tokyo 169-8555 (Japan); Tavakol, Reza, E-mail: shinji@rs.kagu.tus.ac.jp, E-mail: tamaki@gravity.phys.waseda.ac.jp, E-mail: r.tavakol@qmul.ac.uk [Astronomy Unit, School of Mathematical Sciences, Queen Mary University of London, London E1 4NS (United Kingdom)

    2009-05-15

    We study the field profile of a scalar field {phi} that couples to a matter fluid (dubbed a chameleon field) in the relativistic gravitational background of a spherically symmetric spacetime. Employing a linear expansion in terms of the gravitational potential {Phi}{sub c} at the surface of a compact object with a constant density, we derive the thin-shell field profile both inside and outside the object, as well as the resulting effective coupling with matter, analytically. We also carry out numerical simulations for the class of inverse power-law potentials V({phi}) = M{sup 4+n}{phi}{sup -n} by employing the information provided by our analytical solutions to set the boundary conditions around the centre of the object and show that thin-shell solutions in fact exist if the gravitational potential {Phi}{sub c} is smaller than 0.3, which marginally covers the case of neutron stars. Thus the chameleon mechanism is present in the relativistic gravitational backgrounds, capable of reducing the effective coupling. Since thin-shell solutions are sensitive to the choice of boundary conditions, our analytic field profile is very helpful to provide appropriate boundary conditions for {Phi}{sub c}{approx}

  20. Environmental literacy based on educational background

    Science.gov (United States)

    Agfar, A.; Munandar, A.; Surakusumah, W.

    2018-05-01

    This research aims to examine attitude, knowledge and cognitive skill. To collect data we used survey method, was conducted in Pahawang, Lampung. Respondents of this research are coastal society of Pahawang, 114 participants determined using purposive sampling, from two areas in the village, Pahawang and Penggetahan. Data were analyzed using both quantitative and descriptive. Environmental literacy of the society which is primary school graduate is moderate category (85.61), consist of 38.90% in low category and 61.10% in moderate category. Environmental literacy of junior high school graduate is moderate (99.36), consist of 12% in low category, 76% in moderate category and 12% in high category. Environmental literacy of senior high school graduate is moderate (108.85), consist of 84.90% moderate category and 15.10% in high category. But, undergraduate society is high category (118.53). Details 0% low category 52.94% moderate category and 47.06% in high category. This finding research has revelaed that the educational background affects the level of environmental literacy. This finding research has revealed that the educational background affects the level of environmental literacy.

  1. Radioactivity backgrounds in ZEPLIN-III

    Science.gov (United States)

    Araújo, H. M.; Akimov, D. Yu.; Barnes, E. J.; Belov, V. A.; Bewick, A.; Burenkov, A. A.; Chepel, V.; Currie, A.; Deviveiros, L.; Edwards, B.; Ghag, C.; Hollingsworth, A.; Horn, M.; Kalmus, G. E.; Kobyakin, A. S.; Kovalenko, A. G.; Lebedenko, V. N.; Lindote, A.; Lopes, M. I.; Lüscher, R.; Majewski, P.; Murphy, A. St. J.; Neves, F.; Paling, S. M.; Pinto da Cunha, J.; Preece, R.; Quenby, J. J.; Reichhart, L.; Scovell, P. R.; Silva, C.; Solovov, V. N.; Smith, N. J. T.; Smith, P. F.; Stekhanov, V. N.; Sumner, T. J.; Thorne, C.; Walker, R. J.

    2012-03-01

    We examine electron and nuclear recoil backgrounds from radioactivity in the ZEPLIN-III dark matter experiment at Boulby. The rate of low-energy electron recoils in the liquid xenon WIMP target is 0.75 ± 0.05 events/kg/day/keV, which represents a 20-fold improvement over the rate observed during the first science run. Energy and spatial distributions agree with those predicted by component-level Monte Carlo simulations propagating the effects of the radiological contamination measured for materials employed in the experiment. Neutron elastic scattering is predicted to yield 3.05 ± 0.5 nuclear recoils with energy 5-50 keV per year, which translates to an expectation of 0.4 events in a 1 yr dataset in anti-coincidence with the veto detector for realistic signal acceptance. Less obvious background sources are discussed, especially in the context of future experiments. These include contamination of scintillation pulses with Cherenkov light from Compton electrons and from β activity internal to photomultipliers, which can increase the size and lower the apparent time constant of the scintillation response. Another challenge is posed by multiple-scatter γ-rays with one or more vertices in regions that yield no ionisation. If the discrimination power achieved in the first run can be replicated, ZEPLIN-III should reach a sensitivity of ˜1 × 10-8pb · yr to the scalar WIMP-nucleon elastic cross-section, as originally conceived.

  2. Alpha Background Discrimination in the MAJORANA DEMONSTRATOR

    Science.gov (United States)

    Gruszko, Julieta; Majorana Collaboration

    2017-09-01

    The Majorana Demonstrator (MJD) searches for neutrinoless double-beta decay of 76Ge using arrays of high-purity germanium detectors. If observed, this process would have implications for grand-unification and the predominance of matter over antimatter in the universe. A problematic background in such large granular detector arrays is posed by alpha particles. In MJD, potential background events that are consistent with energy-degraded alphas originating on the passivated detector surface have been observed. We have studied these events by scanning the passivated surface of a P-type point contact detector like those used in MJD with a collimated alpha source. We observe that surface alpha events exhibit high charge-trapping, with a significant fraction of the trapped charge being re-released slowly. This leads to both a reduced prompt signal and a measurable change in slope of the tail of a recorded pulse. In this contribution we discuss the characteristics of these events and the filter developed to identify the occurrence of this delayed charge recovery, allowing for the efficient rejection of passivated surface alpha events while retaining 99.8% of bulk events. We also discuss the impact of this filter on the sensitivity of MJD. This material is based upon work supported by the U.S. DOE, Office of Science, Office of Nuclear Phys., the Particle Astrophys. and Nuclear Phys. Programs of the NSF, and SURF. Additional support from the NSFGRFP under Grant No. 1256082.

  3. Particle production in a gravitational wave background

    Science.gov (United States)

    Jones, Preston; McDougall, Patrick; Singleton, Douglas

    2017-03-01

    We study the possibility that massless particles, such as photons, are produced by a gravitational wave. That such a process should occur is implied by tree-level Feynman diagrams such as two gravitons turning into two photons, i.e., g +g →γ +γ . Here we calculate the rate at which a gravitational wave creates a massless scalar field. This is done by placing the scalar field in the background of a plane gravitational wave and calculating the 4-current of the scalar field. Even in the vacuum limit of the scalar field it has a nonzero vacuum expectation value (similar to what occurs in the Higgs mechanism) and a nonzero current. We associate this with the production of scalar field quanta by the gravitational field. This effect has potential consequences for the attenuation of gravitational waves since the massless field is being produced at the expense of the gravitational field. This is related to the time-dependent Schwinger effect, but with the electric field replaced by the gravitational wave background and the electron/positron field quanta replaced by massless scalar "photons." Since the produced scalar quanta are massless there is no exponential suppression, as occurs in the Schwinger effect due to the electron mass.

  4. Bayesian Analysis of the Cosmic Microwave Background

    Science.gov (United States)

    Jewell, Jeffrey

    2007-01-01

    There is a wealth of cosmological information encoded in the spatial power spectrum of temperature anisotropies of the cosmic microwave background! Experiments designed to map the microwave sky are returning a flood of data (time streams of instrument response as a beam is swept over the sky) at several different frequencies (from 30 to 900 GHz), all with different resolutions and noise properties. The resulting analysis challenge is to estimate, and quantify our uncertainty in, the spatial power spectrum of the cosmic microwave background given the complexities of "missing data", foreground emission, and complicated instrumental noise. Bayesian formulation of this problem allows consistent treatment of many complexities including complicated instrumental noise and foregrounds, and can be numerically implemented with Gibbs sampling. Gibbs sampling has now been validated as an efficient, statistically exact, and practically useful method for low-resolution (as demonstrated on WMAP 1 and 3 year temperature and polarization data). Continuing development for Planck - the goal is to exploit the unique capabilities of Gibbs sampling to directly propagate uncertainties in both foreground and instrument models to total uncertainty in cosmological parameters.

  5. Interpretation of observed cosmic microwave background radiation

    International Nuclear Information System (INIS)

    Alfven, H.; Mendis, A.

    1977-01-01

    It is stated that the observed cosmic microwave background radiation, which closely fits a 2.7 K black body spectrum, is generally claimed to be the strongest piece of evidence in support of hot big bang cosmologies by its proponents. It is here stated that the observed radiation corresponds to the distribution of dust in galaxies or protogalaxies with a temperature approximately 110 K at the epoch corresponding to Z approximately 40, and not to a plasma of temperature > approximately 3000 K at an earlier epoch (Z > approximately 1000), as indicated by the canonical model of big bang cosmologies. The claim that the latter lends strong support to hot big bang cosmologies is stated to be without foundation. It is concluded that the microwave background radiation must be explained not in terms of a coupling between matter and radiation at the present epoch, but in terms of a coupling in a previous epoch within the framework of an evolutionary cosmology. (U.K.)

  6. Diffraction, chopping, and background subtraction for LDR

    Science.gov (United States)

    Wright, Edward L.

    1988-01-01

    The Large Deployable Reflector (LDR) will be an extremely sensitive infrared telescope if the noise due to the photons in the large thermal background is the only limiting factor. For observations with a 3 arcsec aperture in a broadband at 100 micrometers, a 20-meter LDR will emit 10(exp 12) per second, while the photon noise limited sensitivity in a deep survey observation will be 3,000 photons per second. Thus the background subtraction has to work at the 1 part per billion level. Very small amounts of scattered or diffracted energy can be significant if they are modulated by the chopper. The results are presented for 1-D and 2-D diffraction calculations for the lightweight, low-cost LDR concept that uses an active chopping quaternary to correct the wavefront errors introduced by the primary. Fourier transforms were used to evaluate the diffraction of 1 mm waves through this system. Unbalanced signals due to dust and thermal gradients were also studied.

  7. Calculation of neutron background for underground experiments

    Energy Technology Data Exchange (ETDEWEB)

    Tomasello, V. [Department of Physics and Astronomy, University of Sheffield, Hounsfield Road, Sheffield S3 7RH (United Kingdom); Physikalisches Institut, Eberhard Karls Universitaet Tuebingen, Auf der Morgenstelle 14, Tuebingen D-72076 (Germany)], E-mail: v.tomasello@sheffield.ac.uk; Kudryavtsev, V.A.; Robinson, M. [Department of Physics and Astronomy, University of Sheffield, Hounsfield Road, Sheffield S3 7RH (United Kingdom)

    2008-10-01

    New generation dark matter experiments aim at exploring the 10{sup -9}-10{sup -10}pb cross-section region for the WIMP-nucleon scalar interactions. Neutrons produced in the detector components are one of the main factors that can limit detector sensitivity. Estimation of the background from this source then becomes a crucial task for designing future large-scale detectors. Energy spectra and production rates for neutrons coming from radioactive contamination are required for all materials in and around the detector. In order to estimate neutron yields and spectra, the cross-sections of ({alpha},n) reactions and probabilities of transitions to different excited states should be known. Cross-sections and transition probabilities have been calculated using EMPIRE2.19 for several isotopes, and for some isotopes, a comparison with the experimental data is shown. The results have been used to calculate the neutron spectra from materials using the code SOURCES4A. Neutron background event rates from some detector components in a hypothetical dark matter detector based on Ge crystals have been estimated. Some requirements for the radiopurity of the materials have been deduced from the results of these simulations.

  8. Calculation of neutron background for underground experiments

    International Nuclear Information System (INIS)

    Tomasello, V.; Kudryavtsev, V.A.; Robinson, M.

    2008-01-01

    New generation dark matter experiments aim at exploring the 10 -9 -10 -10 pb cross-section region for the WIMP-nucleon scalar interactions. Neutrons produced in the detector components are one of the main factors that can limit detector sensitivity. Estimation of the background from this source then becomes a crucial task for designing future large-scale detectors. Energy spectra and production rates for neutrons coming from radioactive contamination are required for all materials in and around the detector. In order to estimate neutron yields and spectra, the cross-sections of (α,n) reactions and probabilities of transitions to different excited states should be known. Cross-sections and transition probabilities have been calculated using EMPIRE2.19 for several isotopes, and for some isotopes, a comparison with the experimental data is shown. The results have been used to calculate the neutron spectra from materials using the code SOURCES4A. Neutron background event rates from some detector components in a hypothetical dark matter detector based on Ge crystals have been estimated. Some requirements for the radiopurity of the materials have been deduced from the results of these simulations

  9. Exposure to background radiation in Australia

    Energy Technology Data Exchange (ETDEWEB)

    Solomon, S.B. [Australian Radiation Lab., Melbourne, VIC (Australia)

    1997-12-31

    The average effective dose received by the Australian population is estimated to be {approx}1.8 mSv / year. One half of this exposure arises from exposure from terrestrial radiation and cosmic rays, the remainder from radionuclides within the body and from inhalation of radon progeny. This paper reviews a number of research programmes carried out by the Australian Radiation Laboratory to study radiation exposure from natural background, particularly in the workplace and illustrate approaches to the quantification and management of exposure to natural radiation. The average radiation doses to the Australian population are relatively low; the average annual radon concentration ranged from 6 Bq m{sup -3} in Queensland to 16 Bq m{sup -3} in the Australian Capital Territory (ACT). Of more importance is the emerging issue of exposure to elevated background radiation in the workplace. Two situation are presented; the radiation exposure to air crues and show cave tour guides. Annual doses up to 3.8 mSv were estimated for international crew members while the highest estimate for show cave tour guides was 9 mSv per year. 9 refs., 2 tabs., 4 figs.

  10. Exposure to background radiation in Australia

    International Nuclear Information System (INIS)

    Solomon, S.B.

    1997-01-01

    The average effective dose received by the Australian population is estimated to be ∼1.8 mSv / year. One half of this exposure arises from exposure from terrestrial radiation and cosmic rays, the remainder from radionuclides within the body and from inhalation of radon progeny. This paper reviews a number of research programmes carried out by the Australian Radiation Laboratory to study radiation exposure from natural background, particularly in the workplace and illustrate approaches to the quantification and management of exposure to natural radiation. The average radiation doses to the Australian population are relatively low; the average annual radon concentration ranged from 6 Bq m -3 in Queensland to 16 Bq m -3 in the Australian Capital Territory (ACT). Of more importance is the emerging issue of exposure to elevated background radiation in the workplace. Two situation are presented; the radiation exposure to air crues and show cave tour guides. Annual doses up to 3.8 mSv were estimated for international crew members while the highest estimate for show cave tour guides was 9 mSv per year

  11. Open bosonic string in background electromagnetic field

    International Nuclear Information System (INIS)

    Nesterenko, V.V.

    1987-01-01

    The classical and quantum dynamics of an open string propagating in the D-dimensional space-time in the presence of a background electromagnetic field is investigated. An important point in this consideration is the use of the generalized light-like gauge. There are considered the strings of two types; the neutral strings with charges at their ends obeying the condition q 1 +q 2 =0 and the charged strings having a net charge q 1 +q 2 ≠ 0. The consistency of theory demands that the background electric field does not exceed its critical value. The distance between the mass levels of the neutral open string decreases (1-e 2 ) times in comparison with the free string, where e is the dimensionless strength of the electric field. The magnetic field does not affect this distance. It is shown that at a classical level the squared mass of the neutral open string has a tachyonic contribution due to the motion of the string as a whole in transverse directions. The tachyonic term disappears if one considers, instead of M 2 , the string energy in a special reference frame where the projection of the total canonical momentum of the string onto the electric field vanishes. The contributions due to zero point fluctuations to the energy spectrum of the neutral string and to the Virasoro operators in the theory of charged string are found

  12. Background compensation methodologies for contamination monitoring systems

    International Nuclear Information System (INIS)

    Raman, Anand; Chaudhury, Probal; Pradeepkumar, K.S.

    2014-01-01

    Radiation surveillance program in the various nuclear facilities incorporate contamination monitoring as an important component. Contamination monitoring programs constitute monitoring for alpha and beta contamination of the physical entities associated with the working personnel that include his hands, feet, clothing, shoes as well as the general surface areas in the working environment like floors. All these measurements are fraught with the contribution of the ambient gamma background radiation fields. These inhibit a proper and precise estimation of the contamination concentration being monitored. This paper investigates the efficacy of two methodologies that have been incorporated in two of the contamination monitoring systems developed in the Division. In the first system discussed, a high degree of gamma compensation has been achieved for an uniform exposure of the order of 50 nSv/hr to 100 mSv/hr. In the second system discussed, the degree of gamma compensation achieved is equal to those dictated by the statistical nature of the uncertainties associated with the subtraction of background from the source data. These two methods can be very effectively employed depending on the application requirement. A minimum detection level equivalent to 0.37 Bq/cdm 2 has been achieved in both these cases

  13. Natural background radiation exposures world-wide

    International Nuclear Information System (INIS)

    Bennett, B.G.

    1993-01-01

    The average radiation dose to the world's population from natural radiation sources has been assessed by UNSCEAR to be 2.4 mSv per year. The components of this exposure, methods of evaluation and, in particular, the variations in the natural background levels are presented in this paper. Exposures to cosmic radiation range from 0.26 mSv per year at sea level to 20 times more at an altitude of 6000 m. Exposures to cosmogenic radionuclides ( 3 H, 14 C) are relatively insignificant and little variable. The terrestrial radionuclides 40 K, 238 U, and 232 Th and the decay products of the latter two constitute the remainder of the natural radiation exposure. Wide variations in exposure occur for these components, particularly for radon and its decay products, which can accumulate to relatively high levels indoors. Unusually high exposures to uranium and thorium series radionuclides characterize the high natural background areas which occur in several localized regions in the world. Extreme values in natural radiation exposures have been estimated to range up to 100 times the average values. (author). 15 refs, 3 tabs

  14. A background to risk analysis. Vol. 4

    International Nuclear Information System (INIS)

    Taylor, J.R.

    1979-01-01

    This 4-volumes report gives a background of ideas, principles, and examples which might be of use in developing practical methods for risk analysis. Some of the risk analysis techniques described are somewhat experimental. The report is written in an introductory style, but where some point needs further justification or evaluation, this is given in the form of a chapter appendix. In this way, it is hoped that the report can serve two purposes, - as a basis for starting risk analysis work and as a basis for discussing effectiveness of risk analysis procedures. The report should be seen as a preliminary stage, prior to a program of industrial trials of risk analysis methods. Vol. 4 treats human error in plant operation. (BP)

  15. A background to risk analysis. Vol. 3

    International Nuclear Information System (INIS)

    Taylor, J.R.

    1979-01-01

    This 4-volumes report gives a background of ideas, principles, and examples which might be of use in developing practical methods for risk analysis. Some of the risk analysis techniques described are somewhat experimental. The report is written in an introductory style, but where some point needs further justifi- cation or evaluation, this is given in the form of a chapter appenix. In this way, it is hoped that the report can serve two purposes, - as a basis for starting risk analysis work and as a basis for discussing effectiveness of risk analysis procedures. The report should be seen as a preliminary stage, prior to a program of industrial trials of risk analysis methods. Vol. 3 contains chapters on quantification of risk, failure and accident probability, risk analysis and design, and examles of risk analysis for process plant. (BP)

  16. Anisotropies in the cosmic microwave background: Theory

    International Nuclear Information System (INIS)

    Dodelson, S.

    1998-02-01

    Anisotropies in the Cosmic Microwave Background (CMB) contain a wealth of information about the past history of the universe and the present values of cosmological parameters. I online some of the theoretical advances of the last few years. In particular, I emphasize that for a wide class of cosmological models, theorists can accurately calculate the spectrum to better than a percent. The spectrum of anisotropies today is directly related to the pattern of inhomogeneities present at the time of recombination. This recognition leads to a powerful argument that will enable us to distinguish inflationary models from other models of structure formation. If the inflationary models turn out to be correct, the free parameters in these models will be determined to unprecedented accuracy by the upcoming satellite missions

  17. Probing η deformed backgrounds with Dp branes

    Directory of Open Access Journals (Sweden)

    Dibakar Roychowdhury

    2018-03-01

    Full Text Available In this Letter, based on the notion of Gauge/Gravity duality we explore the low frequency behaviour associated with the retarded two point correlators in the ground state of the strongly correlated quantum liquid that is dual to η-deformed background in (2+1D. The massless charge carriers in the dual gauge theory are sourced due to some probe Nf flavour Dp brane configurations in the bulk. In our analysis we stick to the NS sector and compute the two point correlators by turning on fluctuations associated with the worldvolume gauge fields in the bulk spacetime. Our analysis reveals the existence of holographic zero sound modes for (1+1D QFTs those are dual to bosonic η deformed AdS3×S3 with vanishing RR fields.

  18. A background to risk analysis. Vol. 2

    International Nuclear Information System (INIS)

    Taylor, J.R.

    1979-01-01

    This 4-volumes report gives a background of ideas, principles and examples which might be of use in developing practical methods for risk analysis. Some of the risk analysis techniques described are somewhat experimental. The report is written in an introductory style, but where some point needs further justification or evaluation, this is given in the form of a chapter appendix. In this way, it is hoped that the report can serve two purposes, - as a basis for starting risk analysis work and as a basis for discussing effectiveness of risk analysis procedures. The report should be seen as a preliminary stage, prior to a program of industrial trials of risk analysis methods. Vol. 2 treats generic methods of qualitative failure analysis. (BP)

  19. How to detect the cosmic neutrino background?

    International Nuclear Information System (INIS)

    Ringwald, A.

    2003-01-01

    A measurement of the big bang relic neutrinos would open a new window to the early universe. We review various possibilities to detect this cosmic neutrino background and substantiate the assertion that - apart from the rather indirect evidence to be gained from cosmology and large-scale structure formation - the annihilation of ultrahigh energy cosmic neutrinos with relic anti-neutrinos (or vice versa) on the Z-resonance is a unique process having sensitivity to the relic neutrinos, if a sufficient flux at E ν i res =M Z 2 /(2m ν i )=4.10 22 eV (0.1 eV/m ν i ) exists. The associated absorption dips in the ultrahigh energy cosmic neutrino spectrum may be searched for at forthcoming neutrino and air shower detectors. The associated protons and photons may have been seen already in form of the cosmic ray events above the Greisen-Zatsepin-Kuzmin cutoff. (orig.)

  20. Epidemiological studies in high background radiation areas

    International Nuclear Information System (INIS)

    Akiba, Suminori

    2012-01-01

    Below the doses of 100-200 mSv of radiation exposure, no acute health effect is observed, and the late health effects such as cancer are yet unclear. The problems making the risk evaluation of low dose radiation exposure difficult are the fact that the magnitude of expected health effects are small even if the risk is assumed to increase in proportion to radiation doses. As a result, studies need to be large particular when dealing with rare disease such as cancer. In addition, the expected health effects are so small that they can easily be masked by lifestyles and environmental factors including smoking. This paper will discuss cancer risk possibly associated with low-dose and low-dose rate radiation exposure, describing epidemiological studies on the residents in the high-background radiation areas. (author)

  1. Social Class, Family Background and Intergenerational Mobility

    DEFF Research Database (Denmark)

    D. Munk, Martin; McIntosh, James

    This research examines the various approaches taken by economists and sociologists for analyzing intergenerational mobility. Social mobility models based on social classes arising from an occupational classification scheme are analyzed. A test for the statistical validity of classification schemes...... is proposed and tested using Danish sample survey data that was first collected in 1976 and augmented in 2000. This is referred to as a homogeneity test and is a likelihood ratio test of a set of linear restrictions which define social classes. For Denmark it is shown that this test fails for an Erikson......-Goldthorpe classification system, raising doubts about the statistical validity of occupational classification systems in general. We also estimate regression models of occupational earnings, household earnings, and educational attainment using family background variables as covariates controlling for unobservables...

  2. Social Class, Family Background and Intergenerational Mobility

    DEFF Research Database (Denmark)

    D. Munk, Martin; McIntosh, James

    This research examines the various approaches taken by economists and sociologists for analyzing intergenerational mobility. Social mobility models based on social classes arising from an occupational classi.cation scheme are analyzed. A test for the statistical validity of classi.cation schemes...... is proposed and tested using Danish sample survey data that was .rst collected in 1976 and augmented in 2000. This is referred to as a homogeneity test and is a likelihood ratio test of a set of linear restrictions which define social classes. For Denmark it is shown that this test fails for an Erikson......-Goldthorpe classi.cation system, raising doubts about the statistical validity of occupational classication systems in general. We also estimate regression models of occupational earnings, household earnings, and educational attainment using family background variables as covariates controlling for unobservables...

  3. Low background techniques for SuperNEMO

    International Nuclear Information System (INIS)

    Liu, Xin Ran; Mott, James

    2015-01-01

    The UK contribution to achieving the ultra-low background conditions required inside the detectors of the SuperNEMO experiment are described. A dedicated facility has been established for the screening and selection of materials through gamma ray spectroscopy using germanium detectors. Initial results from two detectors are shown. The radon level inside the SuperNEMO detector must be less than 150 μBq/m 3 in order to achieve the target sensitivity. A Radon Concentration Line (RnCL) has been developed capable of measuring radon levels in large gas volumes down to 5 μBq/m 3 , improving on standard state-of-the-art radon detectors by 3 orders of magnitude. The development, commissioning and first measurements of radon content using the RnCL are also presented. (paper)

  4. Insights into the background of autonomic medicine.

    Science.gov (United States)

    Laranjo, Sérgio; Geraldes, Vera; Oliveira, Mário; Rocha, Isabel

    2017-10-01

    Knowledge of the physiology underlying the autonomic nervous system is pivotal for understanding autonomic dysfunction in clinical practice. Autonomic dysfunction may result from primary modifications of the autonomic nervous system or be secondary to a wide range of diseases that cause severe morbidity and mortality. Together with a detailed history and physical examination, laboratory assessment of autonomic function is essential for the analysis of various clinical conditions and the establishment of effective, personalized and precise therapeutic schemes. This review summarizes the main aspects of autonomic medicine that constitute the background of cardiovascular autonomic dysfunction. Copyright © 2017 Sociedade Portuguesa de Cardiologia. Publicado por Elsevier España, S.L.U. All rights reserved.

  5. Cosmic Microwave Background Polarization and Inflation

    Science.gov (United States)

    Chuss, David T.

    2011-01-01

    Measurements of the cosmic microwave background (CMB) offer a means to explore the universe at a very early epoch. Specifically, if the universe went through a brief period of exponential expansion called inflation as current data suggest, gravitational waves from this period would polarize the CMB in a specific pattern. At GSFC, we are currently working towards two experiments that work in concert to measure this polarization pattern in search of evidence for inflation. The Cosmology Large Angular Scale Surveyor (CLASS) will measure the polarization at frequencies between 40 and 150 GHz from the Atacama Desert in Chile. The Primordial Inflation Polarization Explorer (PIPER) is a balloon-borne experiment that will make similar measurements at frequencies between 200 and 600 GHz.

  6. On the cosmic microwave background radiation

    Directory of Open Access Journals (Sweden)

    José Maria Filardo Bassalo

    2017-12-01

    Full Text Available In this article we will try to give a pale idea to the reader of what could be the Cosmic Microwave Background (RCFM that, according to the traditional Big Bang model, was generated by a primordial explosion. With this purpose we find it very important to present a brief historical summary of how the Microcosm, based on the Standard Model of Elementary Particle Physics (MPPE, and the Macrocosm, based on the Standard Big Bang Model (MPBB, have evolved over time. In addition, in the final part of the article we will analyze the two physical processes presented in the literature that seek to explain the RCFM: Bariogenesis and Plasma Quark-Gluon.

  7. Retinal Image Preprocessing: Background and Noise Segmentation

    Directory of Open Access Journals (Sweden)

    Usman Akram

    2012-09-01

    Full Text Available Retinal images are used for the automated screening and diagnosis of diabetic retinopathy. The retinal image quality must be improved for the detection of features and abnormalities and for this purpose preprocessing of retinal images is vital. In this paper, we present a novel automated approach for preprocessing of colored retinal images. The proposed technique improves the quality of input retinal image by separating the background and noisy area from the overall image. It contains coarse segmentation and fine segmentation. Standard retinal images databases Diaretdb0, Diaretdb1, DRIVE and STARE are used to test the validation of our preprocessing technique. The experimental results show the validity of proposed preprocessing technique.

  8. [The psychosocial background of sterile patients].

    Science.gov (United States)

    Pusch, H H; Urdl, W; Walcher, W

    1989-01-01

    The psychosocial background of 300 childless couples from the Infertility Clinic of the Department of Gynecology and Obstetrics, University of Graz, was evaluated by means of a questionnaire and statistical analysis of data from their files. Points of special interest were problems such as interactions of the couple, motivations for the desire of children, psychosomatics, andrological investigation within the gynecological department, sexual habits and motivation and compliance concerning investigations and treatment. 72% of the questionnaires were returned. 50% of the sterile couples preferred to attend the infertility clinic together. 26% felt restrictions in their sexual behaviour due to the unrealized desire of children, 48% expected improvements in their partnership if they could have children. Compliance of male partners concerning the regular intake of prescribed medicaments was 83%, 63% accepted to stop smoking in cases of pathospermia.

  9. A background risk analysis. Vol. 1

    International Nuclear Information System (INIS)

    Taylor, J.R.

    1979-01-01

    This 4-volumes report gives a background of ideas, principles, and examples which might be of use in developing practical methods for risk analysis. Some of the risk analysis techniques, described are somewhat experimental. The report is written in an introductory style, but where some point needs further justification or evaluation, this is given in the form of a chapter appendix. In this way, it is hoped that the report can serve two purposes, - as a basis for starting risk analysis work and as a basis for discussing effectiveness of risk analysis procedures. The report should be seen as a preliminary stage, prior to a program of industrial trials of risk analysis methods. Vol. 1 contains a short history of risk analysis, and chapters on risk, failures, errors and accidents, and general procedures for risk analysis. (BP)

  10. Cosmic thermalization and the microwave background radiation

    International Nuclear Information System (INIS)

    Rana, N.C.

    1981-01-01

    A different origin of the microwave background radiation (MBR) is suggested in view of some of the difficulties associated with the standard interpretation. Extensive stellar-type nucleosynthesis could provide radiation with the requisite energy density of the MBR and its spectral features are guaranteed by adequate thermalization of the above radiation by an ambient intergalactic dust medium. This thermalization must have occurred in quite recent epochs, say around epochs of redshift z = 7. The model emerges with consistent limits on the cosmic abundance of helium, the general luminosity evolution of the extragalactic objects, the baryonic matter density in the Universe (or, equivalently the deceleration parameter) and the degree of isotropy of MBR. The model makes definite predictions on issues like the properties of the intergalactic thermalizers, the degree of isotropy of MBR at submillimetre wavelengths and cluster emission in the far infrared. (author)

  11. Observations and modeling of seismic background noise

    Science.gov (United States)

    Peterson, Jon R.

    1993-01-01

    The preparation of this report had two purposes. One was to present a catalog of seismic background noise spectra obtained from a worldwide network of seismograph stations. The other purpose was to refine and document models of seismic background noise that have been in use for several years. The second objective was, in fact, the principal reason that this study was initiated and influenced the procedures used in collecting and processing the data.With a single exception, all of the data used in this study were extracted from the digital data archive at the U.S. Geological Survey's Albuquerque Seismological Laboratory (ASL). This archive dates from 1972 when ASL first began deploying digital seismograph systems and collecting and distributing digital data under the sponsorship of the Defense Advanced Research Projects Agency (DARPA). There have been many changes and additions to the global seismograph networks during the past twenty years, but perhaps none as significant as the current deployment of very broadband seismographs by the U.S. Geological Survey (USGS) and the University of California San Diego (UCSD) under the scientific direction of the IRIS consortium. The new data acquisition systems have extended the bandwidth and resolution of seismic recording, and they utilize high-density recording media that permit the continuous recording of broadband data. The data improvements and continuous recording greatly benefit and simplify surveys of seismic background noise.Although there are many other sources of digital data, the ASL archive data were used almost exclusively because of accessibility and because the data systems and their calibration are well documented for the most part. Fortunately, the ASL archive contains high-quality data from other stations in addition to those deployed by the USGS. Included are data from UCSD IRIS/IDA stations, the Regional Seismic Test Network (RSTN) deployed by Sandia National Laboratories (SNL), and the TERRAscope network

  12. Summarizing background report for Energy Strategy 2025

    International Nuclear Information System (INIS)

    2005-06-01

    The Danish Government's long-term energy strategy follows up on the political agreement of 29 March 2004. The energy strategy is a coherent formulation of the Government's long-term energy policy. The pivotal point for the energy strategy is liberalized energy markets and market based tools for obtaining goals such as efficiency, security of supply and environment. The focus is increasingly on the substantial business potential within development of new and more efficient energy technology, in which Denmark takes up several globally strong positions. Furthermore, transportation energy consumption has been included directly in an energy strategy for the first time. At the same time as the energy strategy is presented, a summarizing background report from the Danish Energy Agency with facts, analyses and evaluations is published, as well as a report from energinet.dk that summarizes the system responsibilities' input to that part of the energy strategy that deals with power infrastructure. (BA)

  13. Multiphoton amplitude in a constant background field

    Science.gov (United States)

    Ahmad, Aftab; Ahmadiniaz, Naser; Corradini, Olindo; Kim, Sang Pyo; Schubert, Christian

    2018-01-01

    In this contribution, we present our recent compact master formulas for the multiphoton amplitudes of a scalar propagator in a constant background field using the worldline fomulation of quantum field theory. The constant field has been included nonperturbatively, which is crucial for strong external fields. A possible application is the scattering of photons by electrons in a strong magnetic field, a process that has been a subject of great interest since the discovery of astrophysical objects like radio pulsars, which provide evidence that magnetic fields of the order of 1012G are present in nature. The presence of a strong external field leads to a strong deviation from the classical scattering amplitudes. We explicitly work out the Compton scattering amplitude in a magnetic field, which is a process of potential relevance for astrophysics. Our final result is compact and suitable for numerical integration.

  14. Detection prospects of the cosmic neutrino background

    Science.gov (United States)

    Li, Yu-Feng

    2015-04-01

    The existence of the cosmic neutrino background (CνB) is a fundamental prediction of the standard Big Bang cosmology. Although current cosmological probes provide indirect observational evidence, the direct detection of the CνB in a laboratory experiment is a great challenge to the present experimental techniques. We discuss the future prospects for the direct detection of the CνB, with the emphasis on the method of captures on beta-decaying nuclei and the PTOLEMY project. Other possibilities using the electron-capture (EC) decaying nuclei, the annihilation of extremely high-energy cosmic neutrinos (EHECνs) at the Z-resonance, and the atomic de-excitation method are also discussed in this review (talk given at the International Conference on Massive Neutrinos, Singapore, 9-13 February 2015).

  15. Speech recognition in natural background noise.

    Directory of Open Access Journals (Sweden)

    Julien Meyer

    Full Text Available In the real world, human speech recognition nearly always involves listening in background noise. The impact of such noise on speech signals and on intelligibility performance increases with the separation of the listener from the speaker. The present behavioral experiment provides an overview of the effects of such acoustic disturbances on speech perception in conditions approaching ecologically valid contexts. We analysed the intelligibility loss in spoken word lists with increasing listener-to-speaker distance in a typical low-level natural background noise. The noise was combined with the simple spherical amplitude attenuation due to distance, basically changing the signal-to-noise ratio (SNR. Therefore, our study draws attention to some of the most basic environmental constraints that have pervaded spoken communication throughout human history. We evaluated the ability of native French participants to recognize French monosyllabic words (spoken at 65.3 dB(A, reference at 1 meter at distances between 11 to 33 meters, which corresponded to the SNRs most revealing of the progressive effect of the selected natural noise (-8.8 dB to -18.4 dB. Our results showed that in such conditions, identity of vowels is mostly preserved, with the striking peculiarity of the absence of confusion in vowels. The results also confirmed the functional role of consonants during lexical identification. The extensive analysis of recognition scores, confusion patterns and associated acoustic cues revealed that sonorant, sibilant and burst properties were the most important parameters influencing phoneme recognition. . Altogether these analyses allowed us to extract a resistance scale from consonant recognition scores. We also identified specific perceptual consonant confusion groups depending of the place in the words (onset vs. coda. Finally our data suggested that listeners may access some acoustic cues of the CV transition, opening interesting perspectives for

  16. Speech recognition in natural background noise.

    Science.gov (United States)

    Meyer, Julien; Dentel, Laure; Meunier, Fanny

    2013-01-01

    In the real world, human speech recognition nearly always involves listening in background noise. The impact of such noise on speech signals and on intelligibility performance increases with the separation of the listener from the speaker. The present behavioral experiment provides an overview of the effects of such acoustic disturbances on speech perception in conditions approaching ecologically valid contexts. We analysed the intelligibility loss in spoken word lists with increasing listener-to-speaker distance in a typical low-level natural background noise. The noise was combined with the simple spherical amplitude attenuation due to distance, basically changing the signal-to-noise ratio (SNR). Therefore, our study draws attention to some of the most basic environmental constraints that have pervaded spoken communication throughout human history. We evaluated the ability of native French participants to recognize French monosyllabic words (spoken at 65.3 dB(A), reference at 1 meter) at distances between 11 to 33 meters, which corresponded to the SNRs most revealing of the progressive effect of the selected natural noise (-8.8 dB to -18.4 dB). Our results showed that in such conditions, identity of vowels is mostly preserved, with the striking peculiarity of the absence of confusion in vowels. The results also confirmed the functional role of consonants during lexical identification. The extensive analysis of recognition scores, confusion patterns and associated acoustic cues revealed that sonorant, sibilant and burst properties were the most important parameters influencing phoneme recognition. . Altogether these analyses allowed us to extract a resistance scale from consonant recognition scores. We also identified specific perceptual consonant confusion groups depending of the place in the words (onset vs. coda). Finally our data suggested that listeners may access some acoustic cues of the CV transition, opening interesting perspectives for future studies.

  17. Background radiation and childhood cancer mortality

    International Nuclear Information System (INIS)

    Sakka, Masatoshi

    1979-01-01

    Oxford Survey of Childhood Cancer estimated an ''extra'' cancer risk of 572 per million man-rad of juvenile cancer deaths under 10 years of age. In Hiroshima and Nagasaki 36.9 juvenile cancers were expected out of 64,490 man-rad of exposed mothers. Observed cancer was, however, only one. The discrepancy was explained partly by possible overlapping of confidence intervals of two samples and partly by excessive doses received by exposed fetuses in Japan. If A-bomb radiation sterilized preleukemic cells induced in fetuses, it must also killed those cells in irradiated adults. Leukemogenic efficiency in adults, about 2.10 -5 per rad, is not different either in A-bomb survivors or in irradiated patients. We examined a dose-effect relationship in childhood cancer mortality (0 - 4 yrs) in Miyagi Prefecture Japan. Ninety two cancers were detected out of 1,214,157 children from 1968 to 1975. They were allocated to 8 districts with different background levels. Population at risk was calculated every year for every district. About 4 deaths occurred every 10,000 man-rad, which is comparable with 572 per million man-rad in Oxford Survey. One out of one thousand infants died from severe malformation in every year when they received 9.8 rad in embryonic stage, the doubling dose is estimated as 20 rad. Clinical and biological significance of the statistical data must be examined in future. Fetal death decreased significantly from 110/1,000 in 1962 to 55/1,000 in 1975. Background radiation plays no role in fetal death in Miyagi Prefecture. (author)

  18. Energy futures project : backgrounder for consultation sessions

    International Nuclear Information System (INIS)

    Bhargava, A.

    2006-05-01

    The National Energy Board periodically publishes a long-term energy and demand report as part of an ongoing monitoring program. The next report is planned for release in 2007. This background document provided background information to ensure that consultation participants have a common understanding of key issues to be addressed during the cross-country consultations that have been planned before the release of the final version of the report. An outline of the proposed analytical approach was presented, as well as details of major assumptions and scenario storylines. Scenario themes included: economic, energy and environmental sustainability; a security-focused world shaped by war and civil strife; and strong global economic growth fueled by the rapid growth of the Chinese and Indian economies. A methodology overview was provided as well as a reference case. Issues related to energy supply included oil; natural gas liquids; natural gas; and electricity. Issues related to energy demand included the residential sector; the commercial sector; the industrial sector; and the transportation sector. Historical trends and forecasts were outlined using the macroeconomic variable of interest. Supply, demand, and supporting infrastructure across all energy forms within a North American and global context were considered. The impact of environmental management strategies were reviewed, as well as the role of the government in shaping policies. It was concluded that the purpose of the final report is to serve as a standard of references for parties interested in Canadian energy issues and trends as well as to inform decision makers of key risks and uncertainties facing the energy future.9 tabs., 1 fig

  19. Polarimeter Arrays for Cosmic Microwave Background Measurements

    Science.gov (United States)

    Stevenson, Thomas; Cao, Nga; Chuss, David; Fixsen, Dale; Hsieh, Wen-Ting; Kogut, Alan; Limon, Michele; Moseley, S. Harvey; Phillips, Nicholas; Schneider, Gideon

    2006-01-01

    We discuss general system architectures and specific work towards precision measurements of Cosmic Microwave Background (CMB) polarization. The CMB and its polarization carry fundamental information on the origin, structure, and evolution of the universe. Detecting the imprint of primordial gravitational radiation on the faint polarization of the CMB will be difficult. The two primary challenges will be achieving both the required sensitivity and precise control over systematic errors. At anisotropy levels possibly as small as a few nanokelvin, the gravity-wave signal is faint compared to the fundamental sensitivity limit imposed by photon arrival statistics, and one must make simultaneous measurements with large numbers, hundreds to thousands, of independent background-limited direct detectors. Highly integrated focal plane architectures, and multiplexing of detector outputs, will be essential. Because the detectors, optics, and even the CMB itself are brighter than the faint gravity-wave signal by six to nine orders of magnitude, even a tiny leakage of polarized light reflected or diffracted from warm objects could overwhelm the primordial signal. Advanced methods of modulating only the polarized component of the incident radiation will play an essential role in measurements of CMB polarization. One promising general polarimeter concept that is under investigation by a number of institutions is to first use planar antennas to separate millimeter-wave radiation collected by a lens or horn into two polarization channels. Then the signals can be fed to a pair of direct detectors through a planar circuit consisting of superconducting niobium microstrip transmission lines, hybrid couplers, band-pass filters, and phase modulators to measure the Stokes parameters of the incoming radiation.

  20. Nonlinear Dynamics of the Cosmic Neutrino Background

    Science.gov (United States)

    Inman, Derek

    At least two of the three neutrino species are known to be massive, but their exact masses are currently unknown. Cosmic neutrinos decoupled from the rest of the primordial plasma early on when the Universe was over a billion times hotter than it is today. These relic particles, which have cooled and are now non-relativistic, constitute the Cosmic Neutrino Background and permeate the Universe. While they are not observable directly, their presence can be inferred by measuring the suppression of the matter power spectrum. This suppression is a linear effect caused by the large thermal velocities of neutrinos, which prevent them from collapsing gravitationally on small scales. Unfortunately, it is difficult to measure because of degeneracies with other cosmological parameters and biases arising from the fact that we typically observe point-like galaxies rather than a continous matter field. It is therefore important to look for new effects beyond linear suppression that may be more sensitive to neutrinos. This thesis contributes to the understanding of the nonlinear dynamics of the cosmological neutrino background in the following ways: (i) the development of a new injection scheme for neutrinos in cosmological N-body simulations which circumvents many issues associated with simulating neutrinos at large redshifts, (ii) the numerical study of the relative velocity field between cold dark matter and neutrinos including its reconstruction from density fields, (iii) the theoretical description of neutrinos as a dispersive fluid and its use in modelling the nonlinear evolution of the neutrino density power spectrum, (iv) the derivation of the dipole correlation function using linear response which allows for the Fermi-Dirac velocity distribution to be properly included, and (v) the numerical study and detection of the dipole correlation function in the TianNu simulation. In totality, this thesis is a comprehensive study of neutrino density and velocity fields that may

  1. Gamma background irradiation. Standards and reality

    International Nuclear Information System (INIS)

    Miloslavov, V.

    1998-01-01

    The systematic deviation of the results of measuring the power of air dose absorbed from the natural gamma background radiation in Bulgaria is inadmissibly large and variable. This in turn augments the dispersion of results as well as the mean value relative to worldwide data, to an implausible level, hardly attributable to the variegated geographical relief of the country. Thus in practice local anthropogenic increases hardly lend themselves to detection and demonstration. In the Radiation Protection Standards (RPS-92) in effect in Bulgaria, and in other documents concerning the same radiation factors as well, the maximum allowable limits for the population as a whole are clearly specified on the basis of worldwide expertise along this line. As a rule these limits are being exceeded by the actually measured values, and for this reason the cited documents contain a clause stipulating that these limits do not refer to the natural radiation background and therefore the latter may be virtually ignored. Thus the basic risk factor for the population goes beyond control at levels commensurable with the officially established limits, its twofold increase inclusive. The maximum allowable limit becomes undefinable. Bearing in mind the fact that in compliance with the cited RPS-92 elimination of the technogenic ionizing radiation sources incorporated in the environment prior to 1992 is 'freezed', it is evident that exposure of the population to anthropogenic radiation becomes legally allowable in a much wider range than the one specified by world legislators. One may anticipate radiation induced health noxae for the population directly or by anthropogenic radiation stress on biocenosis. A relatively large part of the population is susceptible to the effect of low radiation doses. Presumably this contingent will augment as a result of eventual fluctuations. The casual relationship which is difficult to establish should be given due consideration in the analysis of the causes

  2. Robustness of cosmic neutrino background detection in the cosmic microwave background

    CERN Document Server

    Audren, Benjamin; Cuesta, Antonio J; Gontcho, Satya Gontcho A; Lesgourgues, Julien; Niro, Viviana; Pellejero-Ibanez, Marcos; Pérez-Ràfols, Ignasi; Poulin, Vivian; Tram, Thomas; Tramonte, Denis; Verde, Licia

    2015-01-01

    The existence of a cosmic neutrino background can be probed indirectly by CMB experiments, not only by measuring the background density of radiation in the universe, but also by searching for the typical signatures of the fluctuations of free-streaming species in the temperature and polarisation power spectrum. Previous studies have already proposed a rather generic parametrisation of these fluctuations, that could help to discriminate between the signature of ordinary free-streaming neutrinos, or of more exotic dark radiation models. Current data are compatible with standard values of these parameters, which seems to bring further evidence for the existence of a cosmic neutrino background. In this work, we investigate the robustness of this conclusion under various assumptions. We generalise the definition of an effective sound speed and viscosity speed to the case of massive neutrinos or other dark radiation components experiencing a non-relativistic transition. We show that current bounds on these effectiv...

  3. [CLINICAL BACKGROUND ANALYSIS ABOUT TRANSURETHRAL ELECTROCOAGULATION].

    Science.gov (United States)

    Katsui, Masahiro; Kikuchi, Eiji; Yazawa, Satoshi; Hagiwara, Masayuki; Morita, Shinya; Shinoda, Kazunobu; Kosaka, Takeo; Mizuno, Ryuichi; Shinojima, Toshiaki; Asanuma, Hiroshi; Miyajima, Akira; Oya, Mototsugu

    2015-10-01

    Transurethral electrocoagulation (TUC) is a rare event but occurs in a constant manner with various causes or disorders and reduces patient quality of life. So far there have been no reports focusing on the details of TUC. We focused on the clinical background and related causes in cases of TUC in our institution. We identified 76 cases (65 patients) who underwent TUC at Keio University Hospital between April 2001 and March 2011. We focused on patient background, especially with respect to the primary disease, treatment modality, use of antiplatelet or anticoagulant agent, timing of TUC, type of electrosurgical device, and the incidence of transfusion. The primary disease for TUC included bladder tumor (BT) in 31 cases, benign prostate hyperplasia (BPH) in 13, prostate cancer (PCa) in 13, idiopathic bladder bleeding in 4, periarteritis nodosa in 3, uterine cervical cancer in 3, and others in 9. TUC after transurethral resection (TUR) was found in 38 cases, including transurethral resection of bladder tumor (TURBT) in 26 of 31 BT cases and transurethral resection of prostate (TURP) in 12 of 13 BPH cases. After TURBT, TUC was performed before removal of a urethral catheter in 7 cases, and after removal of a urethral catheter in 19 cases. With regard to TUC associated with TURP, the average estimated prostate volume in TUC cases before removal of the urethral catheter was 66.2 ml, which was significantly larger than that in TUC cases after removal of the urethral catheter (46.1 ml, p = 0.045). TUC after the radiation therapy was observed in 21 cases, and the average time from the radiation therapy to TUC was 3.4 years (7 months-10 years). TUC was caused by multiple causes or disorders, and 75% of our TUC was associated with BT, BPH or PCa. TUC associated with TURBT frequently occurred within 1 week after TURBT but was still observed after 1 month following the operation. All TUC associated with TURP occurred within 3 weeks after operation. The average period from

  4. Zero modes in de Sitter background

    Energy Technology Data Exchange (ETDEWEB)

    Einhorn, Martin B. [Kavli Institute for Theoretical Physics, University of California,Santa Barbara, CA 93106-4030 (United States); Jones, D.R. Timothy [Kavli Institute for Theoretical Physics, University of California,Santa Barbara, CA 93106-4030 (United States); Dept. of Mathematical Sciences, University of Liverpool,Liverpool L69 3BX (United Kingdom)

    2017-03-28

    There are five well-known zero modes among the fluctuations of the metric of de Sitter (dS) spacetime. For Euclidean signature, they can be associated with certain spherical harmonics on the S{sup 4} sphere, viz., the vector representation 5 of the global SO(5) isometry. They appear, for example, in the perturbative calculation of the on-shell effective action of dS space, as well as in models containing matter fields. These modes are shown to be associated with collective modes of S{sup 4} corresponding to certain coherent fluctuations. When dS space is embedded in flat five dimensions E{sup 5}, they may be seen as a legacy of translation of the center of the S{sup 4} sphere. Rigid translations of the S{sup 4}-sphere on E{sup 5} leave the classical action invariant but are unobservable displacements from the point of view of gravitational dynamics on S{sup 4}. Thus, unlike similar moduli, the center of the sphere is not promoted to a dynamical degree of freedom. As a result, these zero modes do not signify the possibility of physically realizable fluctuations or flat directions for the metric of dS space. They are not associated with Killing vectors on S{sup 4} but can be identified with certain non-isometric, conformal Killing forms that locally correspond to a rescaling of the volume element dV{sub 4}. We frame much of our discussion in the context of renormalizable gravity, but, to the extent that they only depend upon the global symmetry of the background, the conclusions should apply equally to the corresponding zero modes found in Einstein gravity. Although their existence has only been demonstrated at one-loop, we expect that these zero modes will be present to all orders in perturbation theory. They will occur for Lorentzian signature as well, so long as the hyperboloid H{sup 4} is locally stable, but there remain certain infrared issues that need to be clarified. We conjecture that they will appear in any gravitational theory having dS background as a

  5. Novel Techniques for Background / Foreground Rejection in Particle Instruments

    Data.gov (United States)

    National Aeronautics and Space Administration — The Novel Techniques for Background / Foreground Rejection in Particle Instruments project addresses the need for signal contamination and background signal...

  6. Measurement of fast neutron background in SAGE

    CERN Document Server

    Abdurashitov, J N; Kalikhov, A V; Matushko, V L; Shikhin, A A; Yants, V E; Zaborskaia, O S

    2002-01-01

    The spectrometer intended for direct measurements of ultra low fluxes of fast neutrons is described. It is sensitive to neutron fluxes of 10 sup - sup 7 cm sup - sup 2 s sup - sup 1 and lower. The detection efficiency of fast neutrons with simultaneous energy measurement was determined from Monte-Carlo simulation to be equal to 0.11 +- 0.01. The background counting rate in the detector corresponds to a neutron flux of (6.5 +- 2.1) x 10 sup - sup 7 cm sup - sup 2 s sup - sup 1 in the range 1.0-11.0 MeV. The natural neutron flux from the surrounding mine rock at the depth of 4700 meters of water equivalent was measured to be (7.3 +- 2.4) x 10 sup - sup 7 cm sup - sup 2 s sup - sup 1 in the range 1.0-11.0 MeV. The flux of fast neutrons in the SAGE main room was measured to be < 2.3 x 10 sup - sup 7 cm sup - sup 2 s sup - sup 1 in 1.0-11.0 MeV energy range.

  7. Measurement of fast neutron background in SAGE

    International Nuclear Information System (INIS)

    Abdurashitov, J.N.; Gavrin, V.N.; Kalikhov, A.V.; Matushko, V.L.; Shikhin, A.A.; Yants, V.E.; Zaborskaia, O.S.

    2002-01-01

    The spectrometer intended for direct measurements of ultra low fluxes of fast neutrons is described. It is sensitive to neutron fluxes of 10 -7 cm -2 s -1 and lower. The detection efficiency of fast neutrons with simultaneous energy measurement was determined from Monte-Carlo simulation to be equal to 0.11 ± 0.01. The background counting rate in the detector corresponds to a neutron flux of (6.5 ± 2.1) x 10 -7 cm -2 s -1 in the range 1.0-11.0 MeV. The natural neutron flux from the surrounding mine rock at the depth of 4700 meters of water equivalent was measured to be (7.3 ± 2.4) x 10 -7 cm -2 s -1 in the range 1.0-11.0 MeV. The flux of fast neutrons in the SAGE main room was measured to be -7 cm -2 s -1 in 1.0-11.0 MeV energy range

  8. Background simulation for the COBRA-experiment

    Energy Technology Data Exchange (ETDEWEB)

    Quante, Thomas [TU Dortmund, Institut fuer Physik (Germany); Collaboration: COBRA-Collaboration

    2015-07-01

    COBRA is a next-generation experiment searching for neutrinoless double beta (0νββ) decay using CdZnTe semiconductor detectors. The main focus is on {sup 116}Cd, with a Q-value of 2813.5 keV well above the highest dominant naturally occurring gamma lines. By measuring the half-life of the 0νββ decay, it is possible to clarify the nature of the neutrino as either Dirac or Majorana particle and furthermore to determine the effective Majorana mass. COBRA is currently in the demonstrator phase to study possible background contributions and gain information about the longterm stability of the used detectors. For this purpose a demonstrator array made up of 64 Cadmium-Zinc-Telluride (CdZnTe) semiconductor detectors in coplanar grid configuration was designed and realised at the Gran Sasso Underground laboratory (LNGS) in Italy. Simulations of the whole demonstrator setup are ongoing to reproduce the measured spectra for each detector. This is done in two steps. The first uses the Geant4 based framework VENOM for tracking and energy deposition inside each detector. Detector effects like the energy resolution and electron trapping have to be applied in the second step. The used detector geometry has to be verified against calibration measurements. This talk gives an overview of the current simulation status.

  9. Genetic background of aggressive behaviour in dogs

    Directory of Open Access Journals (Sweden)

    Witold Stanisław Proskura

    2013-01-01

    Full Text Available The background of aggression is very complicated and the basis of its occurrence has not been well explained yet. It is thought that tendency to aggressiveness is an effect of both environmental and genetic factors. Aggression is a very undesirable behavioural trait in dogs living with humans. The aim of this study was to determine the relationship between two polymorphisms: DRD4 intron II VNTR and C/T substitution in exon I HTR2B genes and aggressive behaviour in dogs. The VNTR polymorphism in the DRD4 gene was detected by agarose gel electrophoresis following PCR amplification, whereas C/T substitution in the HTR2B gene was analysed using amplification created restriction site-polymerase chain reaction (ACRS-PCR. A total of 121 dogs of several breeds were analyzed. All animals were classified based on a veterinary interview and observation in two groups: aggressive (n = 21 and non-aggressive (n = 100. Significant differences in DRD4 genotype frequencies between aggressive and non-aggressive dogs were observed (P DRD4 gene with the occurrence of aggressive behaviour in dogs. Moreover, the findings give good justification for further research aimed at evaluation of the possibility of using this genetic marker in Marker-assisted Selection.

  10. The Physics of the Cosmic Microwave Background

    Energy Technology Data Exchange (ETDEWEB)

    Peacock, John [Royal Observatory, Edinburgh (United Kingdom)

    2007-04-07

    The award of the 2006 Nobel Prize for Physics is a reminder to non-specialists that the cosmic microwave background (CMB) has yielded astonishing advances in our understanding of cosmology. Mather and Smoot received their prize for work done with NASA's COBE satellite in the early 1990s, but the subject has if anything accelerated since then. The results from NASA's WMAP satellite, reported in 2003 and 2006, have proved COBE's equal in importance and have generated huge worldwide interest. There could therefore hardly be a better time to be writing a detailed textbook to explain what the fuss is all about to a new generation of research students. A comprehensive treatment of the physics of the CMB is not easy to achieve, because it is connected to so much else in cosmology. A student must have a background knowledge of the geometry and dynamics of an expanding universe, plus a deep exposure to the physics of quantum fields, in order to understand the modern 'inflationary' view in which the universe was set expanding by the tension of the vacuum, and was seeded with small inhomogeneities as a result of quantum fluctuations. Although the theory of inflation is not yet verified, the CMB has the potential to accomplish this; testing inflation is undoubtedly one of the principal aims of cosmology over the next decade. Even with this preparation, understanding the properties of the CMB is quite hard at the professional level, requiring the perturbation expansion of the relativistic Boltzmann equation. These technical difficulties are particularly strong in the frontier area of CMB polarization. Naselsky and his collaborators have allocated themselves a relatively brief 255 pages in which to meet these challenges, so some compromise is inevitable. Although the preface is not explicit about the assumed prior knowledge, no systematic material on background cosmology or on inflation is to be found. The former is reasonable in a graduate-level text

  11. The AAVSO 2011 Demographic and Background Survey

    Science.gov (United States)

    Price, A.

    2012-04-01

    In 2011, the AAVSO conducted a survey of 615 people who are or were recently active in the organization. The survey included questions about their demographic background and variable star interests. Data are descriptively analyzed and compared with prior surveys. Results show an organization of very highly educated, largely male amateur and professional astronomers distributed across 108 countries. Participants tend to be loyal, with the average time of involvement in the AAVSO reported as 14 years. Most major demographic factors have not changed much over time. However, the average age of new members is increasing. Also, a significant portion of the respondents report being strictly active in a non-observing capacity, reflecting the growing mission of the organization. Motivations of participants are more aligned with scientific contribution than with that reported by other citizen science projects. This may help explain why a third of all respondents are an author or co-author of a paper in an astronomical journal. Finally, there is some evidence that participation in the AAVSO has a greater impact on the respondents' view of their role in astronomy compared to that expected through increasing amateur astronomy experience alone.

  12. Facial and bodily correlates of family background.

    Science.gov (United States)

    Boothroyd, Lynda G; Perrett, David I

    2006-09-22

    It has been suggested that absence of the father during early childhood has long-reaching effects on reproductive strategy and development of offspring. This paper reports two studies designed to investigate the physical characteristics of daughters associated with father absence. Study 1 used a facial averaging method to produce composite images of faces of women whose parents separated during their childhood (who were 'father absent'), women whose parents remained together, but had poor quality relationships and women whose parents were together and had good quality relationships. Images were then rated by male and female judges. Father absence and poor parental relationships were associated with apparent facial masculinity and reduced attractiveness in daughters. Poor parental relationships were also associated with reduced apparent health. Study 2 compared family background with body measurements and found that father absence or a poor quality relationship between parents were associated with body masculinity (high waist-to-hip ratio) and increased weight-for-height and adiposity. These results highlight the possibility of physical masculinization being associated with purported father absence 'effects'.

  13. Background to the workshop: purpose and objectives

    International Nuclear Information System (INIS)

    Griffiths, J.S.

    2000-01-01

    In its report on future regulatory challenges, CNRA identified the human element as one of the most critical aspects of maintaining regulatory effectiveness, efficiency and quality of work. There is a need to preserve among the staff a collective knowledge in all relevant technical disciplines with sufficient depth to permit adequate independent assessment of safety issues. Quality organisations require well educated well trained and well motivated staff. In some countries national R and D programmes are being replaced to such a point that forming an independent regulatory position might be in jeopardy. If a significant problem occurred over the next ten years there might not be sufficient knowledge and capability to deal with it in a timely manner if the current trend continues. It is against this background that CNRA recommended this workshop should be organised to consider these human issues in relation to maintaining corporate knowledge, both within the industry and regulatory bodies. This is a complex issue as there are different circumstances in each country arising from the status of the industry and its economic and political interactions. A simple model for considering these interactions is set out in Figure 1. (author)

  14. Probing Inflation via Cosmic Microwave Background Polarimetry

    Science.gov (United States)

    Chuss, David T.

    2008-01-01

    The Cosmic Microwave Background (CMB) has been a rich source of information about the early Universe. Detailed measurements of its spectrum and spatial distribution have helped solidify the Standard Model of Cosmology. However, many questions still remain. Standard Cosmology does not explain why the early Universe is geometrically flat, expanding, homogenous across the horizon, and riddled with a small anisotropy that provides the seed for structure formation. Inflation has been proposed as a mechanism that naturally solves these problems. In addition to solving these problems, inflation is expected to produce a spectrum of gravitational waves that will create a particular polarization pattern on the CMB. Detection of this polarized signal is a key test of inflation and will give a direct measurement of the energy scale at which inflation takes place. This polarized signature of inflation is expected to be -9 orders of magnitude below the 2.7 K monopole level of the CMB. This measurement will require good control of systematic errors, an array of many detectors having the requisite sensitivity, and a reliable method for removing polarized foregrounds, and nearly complete sky coverage. Ultimately, this measurement is likely to require a space mission. To this effect, technology and mission concept development are currently underway.

  15. Statistics of cosmic microwave background polarization

    International Nuclear Information System (INIS)

    Kamionkowski, M.; Kosowsky, A.; Stebbins, A.

    1997-01-01

    We present a formalism for analyzing a full-sky temperature and polarization map of the cosmic microwave background. Temperature maps are analyzed by expanding over the set of spherical harmonics to give multipole moments of the two-point correlation function. Polarization, which is described by a second-rank tensor, can be treated analogously by expanding in the appropriate tensor spherical harmonics. We provide expressions for the complete set of temperature and polarization multipole moments for scalar and tensor metric perturbations. Four sets of multipole moments completely describe isotropic temperature and polarization correlations; for scalar metric perturbations one set is identically zero, giving the possibility of a clean determination of the vector and tensor contributions. The variance with which the multipole moments can be measured in idealized experiments is evaluated, including the effects of detector noise, sky coverage, and beam width. Finally, we construct coordinate-independent polarization two-point correlation functions, express them in terms of the multipole moments, and derive small-angle limits. copyright 1997 The American Physical Society

  16. On the spatial behavior of background plasma in different background pressure in CPS device

    International Nuclear Information System (INIS)

    Samantaray, Subrata; Paikaray, Rita; Sahoo, Gourishankar; Das, Parthasarathi; Ghosh, Joydeep; Sanyasi, Amulya Kumar

    2015-01-01

    Blob formation and transport is a major concern for investigators as it greatly reduces the efficiency of the devices. Initial results from CPS device confirm the role of fast neutrals inside the bulk plasma in the process of blob formation and transport. 2-D simulation of curvature and velocity shear instability in plasma structures suggest that in the presence of background plasma, secondary instability do not grow non-linearly to a high level and stabilizes the flow. Adiabaticity effect also creates a radial barrier for interchange modes. In the absence of background plasma the blob fragments even at the modest level of viscosity. The fast neutrals outside bulk plasma supposed to stabilize the system. The background plasma set up is aimed at creating fast neutrals outside main plasma column, hence; the background plasma set up is done in CPS device. The spatial behavior of plasma column in between electrodes is different for different base pressure in CPS device. The spatial variation of electron temperature of plasma column between electrodes is presented in this communication. Electron temperature is measured from emission spectroscopy data. The maximum electron temperature (line averaged) is ∼ 1.5 eV. (author)

  17. Robustness of cosmic neutrino background detection in the cosmic microwave background

    Energy Technology Data Exchange (ETDEWEB)

    Audren, Benjamin [Institut de Théorie des Phénomènes Physiques, École Polytechnique Fédérale de Lausanne, CH-1015, Lausanne (Switzerland); Bellini, Emilio; Cuesta, Antonio J.; Verde, Licia [Institut de Ciències del Cosmos, Universitat de Barcelona, IEEC-UB, Martí i Franquès 1, E08028 Barcelona (Spain); Gontcho, Satya Gontcho A; Pérez-Ràfols, Ignasi [Dept. d' Astronomia i Meteorologia, Institut de Ciències del Cosmos, Universitat de Barcelona, IEEC-UB, Martí i Franquès 1, E08028 Barcelona (Spain); Lesgourgues, Julien [CERN, Theory Division, CH-1211 Geneva 23 (Switzerland); Niro, Viviana [Departamento de Física Teórica, Universidad Autónoma de Madrid and Instituto de Física Teórica UAM/CSIC, Calle Nicolás Cabrera 13-15, Cantoblanco, E-28049 Madrid (Spain); Pellejero-Ibanez, Marcos; Tramonte, Denis [Instituto de Astrofísica de Canarias (IAC), C/Vía Láctea s/n, E-38200, La Laguna, Tenerife (Spain); Poulin, Vivian [LAPTh, Université de Savoie, CNRS, B.P.110, Annecy-le-Vieux F-74941 (France); Tram, Thomas, E-mail: emilio.bellini@icc.ub.edu [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Burnaby Road, Portsmouth PO1 3FX (United Kingdom)

    2015-03-01

    The existence of a cosmic neutrino background can be probed indirectly by CMB experiments, not only by measuring the background density of radiation in the universe, but also by searching for the typical signatures of the fluctuations of free-streaming species in the temperature and polarisation power spectrum. Previous studies have already proposed a rather generic parametrisation of these fluctuations, that could help to discriminate between the signature of ordinary free-streaming neutrinos, or of more exotic dark radiation models. Current data are compatible with standard values of these parameters, which seems to bring further evidence for the existence of a cosmic neutrino background. In this work, we investigate the robustness of this conclusion under various assumptions. We generalise the definition of an effective sound speed and viscosity speed to the case of massive neutrinos or other dark radiation components experiencing a non-relativistic transition. We show that current bounds on these effective parameters do not vary significantly when considering an arbitrary value of the particle mass, or extended cosmological models with a free effective neutrino number, dynamical dark energy or a running of the primordial spectrum tilt. We conclude that it is possible to make a robust statement about the detection of the cosmic neutrino background by CMB experiments.

  18. The Institute of American Indian Arts Background Information (Task One of the Transition Evaluation). Background Paper.

    Science.gov (United States)

    Tippeconnic, John W., Jr.

    The paper, prepared as Task One of the Institute of American Indian Arts Transition Evaluation, provides pertinent background information about the Institute of American Indian Arts in Santa Fe, New Mexico. A brief history of the Institute is given, with information about its philosophy and purpose; objectives; organization and administration; the…

  19. Near-Earth Object (NEO) Hazard Background

    Science.gov (United States)

    Mazanek, Daniel D.

    2005-01-01

    The fundamental problem regarding NEO hazards is that the Earth and other planets, as well as their moons, share the solar system with a vast number of small planetary bodies and orbiting debris. Objects of substantial size are typically classified as either comets or asteroids. Although the solar system is quite expansive, the planets and moons (as well as the Sun) are occasionally impacted by these objects. We live in a cosmic shooting gallery where collisions with Earth occur on a regular basis. Because the number of smaller comets and asteroids is believed to be much greater than larger objects, the frequency of impacts is significantly higher. Fortunately, the smaller objects, which are much more numerous, are usually neutralized by the Earth's protective atmosphere. It is estimated that between 1000 and 10,000 tons of debris fall to Earth each year, most of it in the form of dust particles and extremely small meteorites. With no atmosphere, the Moon's surface is continuously impacted with dust and small debris. On November 17 and 18, 1999, during the annual Leonid meteor shower, several lunar surface impacts were observed by amateur astronomers in North America. The Leonids result from the Earth's passage each year through the debris ejected from Comet Tempel-Tuttle. These annual showers provide a periodic reminder of the possibility of a much more consequential cosmic collision, and the heavily cratered lunar surface acts a constant testimony to the impact threat. The impact problem and those planetary bodies that are a threat have been discussed in great depth in a wide range of publications and books, such as The Spaceguard Survey , Hazards Due to Comets and Asteroids, and Cosmic Catastrophes. This paper gives a brief overview on the background of this problem and address some limitations of ground-based surveys for detection of small and/or faint near-Earth objects.

  20. Spectral measurements of the cosmic microwave background

    Energy Technology Data Exchange (ETDEWEB)

    Kogut, A.J.

    1989-04-01

    Three experiments have measured the intensity of the Cosmic Microwave Background (CMB) at wavelengths 4.0, 3.0, and 0.21 cm. The measurement at 4.0 cm used a direct-gain total-power radiometer to measure the difference in power between the zenith sky and a large cryogenic reference target. Foreground signals are measured with the same instrument and subtracted from the zenith signal, leaving the CMB as the residual. The reference target consists of a large open-mouth cryostat with a microwave absorber submerged in liquid helium; thin windows block the radiative heat load and prevent condensation atmospheric gases within the cryostat. The thermodynamic temperature of the CMB at 4.0 cm is 2.59 +- 0.07 K. The measurement at 3.0 cm used a superheterodyne Dicke-switched radiometer with a similar reference target to measure the zenith sky temperature. A rotating mirror allowed one of the antenna beams to be redirected to a series of zenith angles, permitting automated atmospheric measurements without moving the radiometer. A weighted average of 5 years of data provided the thermodynamic temperature of the CMB at 3.0 cm of 2.62 +- 0.06 K. The measurement at 0.21 cm used Very Large Array observations of interstellar ortho-formaldehyde to determine the CMB intensity in molecular clouds toward the giant HII region W51A (G49.5-0.4). Solutions of the radiative transfer problem in the context of a large velocity gradient model provided estimates of the CMB temperature within the foreground clouds. Collisional excitation from neutral hydrogen molecules within the clouds limited the precision of the result. The thermodynamic temperature of the CMB at 0.21 cm is 3.2 +- 0.9 K. 72 refs., 27 figs., 38 tabs.

  1. Climate Impacts on Northern Canada: Regional Background

    Energy Technology Data Exchange (ETDEWEB)

    Prowse, Terry D.; Peters, Daniel L. (Water and Climate Impacts Research Centre, Environment Canada, Dept. of Geography, Univ. of Victoria, Victoria, BC (Canada)). e-mail: terry.prowse@ec.gc.caa; Furgal, Chris (Indigenous Environmental Studies Program, Trent Univ., Peterborough, ON (Canada)); Bonsal, Barrie R. (National Water Research Inst., National Hydrology Research Centre, Environment Canada, Saskatoon, SK (Canada))

    2009-07-15

    Understanding the implications of climate change on northern Canada requires a background about the size and diversity of its human and biogeophysical systems. Occupying an area of almost 40% of Canada, with one-third of this contained in Arctic islands, Canada's northern territories consist of a diversity of physical environments unrivaled around the circumpolar north. Major ecozones composed of a range of landforms, climate, vegetation, and wildlife include: Arctic, boreal and taiga cordillera; boreal and taiga plains; taiga shield; and northern and southern Arctic. Although generally characterized by a cold climate, there is an enormous range in air temperature with mean annual values being as high as -5 deg C in the south to as low as -20 deg C in the high Arctic islands. A similar contrast characterizes precipitation, which can be >700 mm y-1 in some southern alpine regions to as low as 50 mm y-1 over islands of the high Arctic. Major freshwater resources are found within most northern ecozones, varying from large glaciers or ice caps and lakes to extensive wetlands and peat lands. Most of the North's renewable water, however, is found within its major river networks and originates in more southerly headwaters. Ice covers characterize the freshwater systems for multiple months of the year while permafrost prevails in various forms, dominating the terrestrial landscape. The marine environment, which envelops the Canadian Arctic Archipelago, is dominated by seasonal to multiyear sea ice often several meters thick that plays a key role in the regional climate. Almost two-thirds of northern Canadian communities are located along coastlines with the entire population being just over 100 000. Most recent population growth has been dominated by an expansion of nonaboriginals, primarily the result of resource development and the growth of public administration. The economies of northern communities, however, remain quite mixed with traditional land

  2. Background parenchymal enhancement in preoperative breast MRI.

    Science.gov (United States)

    Kohara, Satoko; Ishigaki, Satoko; Satake, Hiroko; Kawamura, Akiko; Kawai, Hisashi; Kikumori, Toyone; Naganawa, Shinji

    2015-08-01

    We aimed to assess the influence of background parenchymal enhancement (BPE) on surgical planning performed using preoperative MRI for breast cancer evaluation. Between January 2009 and December 2010, 91 newly diagnosed breast cancer patients (mean age, 55.5 years; range, 30-88 years) who underwent preoperative bilateral breast MRI followed by planned breast conservation therapy were retrospectively enrolled. MRI was performed to assess the tumor extent in addition to mammography and breast ultrasonography. BPE in the contralateral normal breast MRI at the early dynamic phase was visually classified as follows: minimal (n=49), mild (n=27), moderate (n=7), and marked (n=8). The correlations between the BPE grade and age, menopausal status, index tumor size, changes in surgical management based on MRI results, positive predictive value (PPV) of MRI, and surgical margins were assessed. Patients in the strong BPE groups were significantly younger (p=0.002) and generally premenopausal (p<0.001). Surgical treatment was not changed in 67 cases (73.6%), while extended excision and mastectomy were performed in 12 cases (13.2%), each based on additional lesions on MRI. Six of 79 (7.6%) patients who underwent breast conservation therapy had tumor-positive resection margins. In cases where surgical management was changed, the PPV for MRI-detected foci was high in the minimal (91.7%) and mild groups (66.7%), and 0% in the moderate and marked groups (p=0.002). Strong BPE causes false-positive MRI findings and may lead to overly extensive surgery, whereas MRI may be beneficial in select patients with weak BPE.

  3. Spectral measurements of the cosmic microwave background

    International Nuclear Information System (INIS)

    Kogut, A.J.

    1989-04-01

    Three experiments have measured the intensity of the Cosmic Microwave Background (CMB) at wavelengths 4.0, 3.0, and 0.21 cm. The measurement at 4.0 cm used a direct-gain total-power radiometer to measure the difference in power between the zenith sky and a large cryogenic reference target. Foreground signals are measured with the same instrument and subtracted from the zenith signal, leaving the CMB as the residual. The reference target consists of a large open-mouth cryostat with a microwave absorber submerged in liquid helium; thin windows block the radiative heat load and prevent condensation atmospheric gases within the cryostat. The thermodynamic temperature of the CMB at 4.0 cm is 2.59 +- 0.07 K. The measurement at 3.0 cm used a superheterodyne Dicke-switched radiometer with a similar reference target to measure the zenith sky temperature. A rotating mirror allowed one of the antenna beams to be redirected to a series of zenith angles, permitting automated atmospheric measurements without moving the radiometer. A weighted average of 5 years of data provided the thermodynamic temperature of the CMB at 3.0 cm of 2.62 +- 0.06 K. The measurement at 0.21 cm used Very Large Array observations of interstellar ortho-formaldehyde to determine the CMB intensity in molecular clouds toward the giant HII region W51A (G49.5-0.4). Solutions of the radiative transfer problem in the context of a large velocity gradient model provided estimates of the CMB temperature within the foreground clouds. Collisional excitation from neutral hydrogen molecules within the clouds limited the precision of the result. The thermodynamic temperature of the CMB at 0.21 cm is 3.2 +- 0.9 K. 72 refs., 27 figs., 38 tabs

  4. Cosmic microwave background polarization results from QUIET

    International Nuclear Information System (INIS)

    Buder, I.

    2014-01-01

    Despite the success of precision cosmology, cosmologists cannot fully explain the initial conditions of the Universe. Inflation, an exponential expansion in the first ∼ 10 -36 s, is a promising potential explanation. A generic prediction of inflation is odd-parity (B-mode) polarization in the cosmic microwave background (CMB). Q/U Imaging Experiment (QUIET) aimed at limiting or detecting this polarization. We built a pseudo-correlation microwave polarimeter as an array of mass-produced modules in the focal plane of a 1.4 m telescope. We used rotation around the absorbing ground screen, a new time-stream double-demodulation technique, and optimized optics in the design to reduce instrumental polarization. We observed with this instrument at the Atacama Plateau in Chile between October 2008 and December 2010. This paper describes the analysis and results of these observations from one of 2 parallel pipelines. We developed noise modeling, filtering and data selection following a blind-analysis strategy. Central to this strategy was a suite of null test, each motivated by a possible instrumental problem or systematic effect. We evaluated the systematic errors in the blind stage of the analysis before the result was known. We calculated the CMB power spectra using a pseudo-C l cross-correlation technique that suppressed contamination and made the result insensitive to noise bias. We measured the first 3 peaks of the E-mode spectrum at high significance and limited B-mode polarization. We measured the CMB polarization power at 25 ≤ l ≤ 975. We found no statistically significant deviation from ΛCDM model, and our results are consistent with zero BB and EB power. Systematic errors were well below our B-mode polarization limits. This systematic-error reduction was a strong demonstration of technology for application in more sensitive, next generation CMB experiments. (author)

  5. Redistribution of energetic particles by background turbulence

    International Nuclear Information System (INIS)

    Hauff, T.; Jenko, F.

    2007-01-01

    The quest to understand the turbulent transport of particles, momentum and energy in magnetized plasmas remains a key challenge in fusion research. A basic issue being .still relatively poorly understood is the turbulent ExB advection of charged test particles with large gyroradii. Especially the interaction of alpha particles or impurities with the background turbulence is of great interest. In order to understand the dependence of the particle diffusivity on the interaction mechanisms between FLR effects and the special structure of a certain type of turbulence, direct numerical simulations are done in artificially created two dimensional turbulent electrostatic fields, assuming a constant magnetic field. Finite gyroradius effects are introduced using the gyrokinetic approximation which means that the gyrating particle is simply replaced by a charged ring. Starting from an idealized isotropic potential with Gaussian autocorrelation function, numerous test particle simulations are done varying both the gyroradius and the Kubo number of the potential. It is found that for Kubo numbers larger than about unity, the particle diffusivity is almost independent of the gyroradius as long as the latter does not exceed the correlation length of the electrostatic potential, whereas for small Kubo numbers the diffusivity is monotonically reduced. The underlying physical mechanisms of this behavior are identified and an analytic approach is developed which favorably agrees with the simulation results. The investigations are extended by introducing anisotropic structures like streamers and zonal flows into the artificial potential, leading to quantitative modulations of the gyroradius dependence of the diffusion coefficient. Analytic models are used to explain these various effects. After having developed a general overview on the behavior in simplified artificial potentials, test particle simulations in realistic turbulence created by the gyrokinetic turbulence code GENE are

  6. Temperature fluctuations superimposed on background temperature change

    International Nuclear Information System (INIS)

    Otto, James; Roberts, J.A.

    2016-01-01

    Proxy data allows the temperature of the Earth to be mapped over long periods of time. In this work the temperature fluctuations for over 200 proxy data sets were examined and from this set 50 sets were analyzed to test for periodic and quasi-periodic fluctuations in the data sets. Temperature reconstructions over 4 different time scales were analyzed to see if patterns emerged. Data were put into four time intervals; 4,000 years, 14,000 years, 1,000,000 years, and 3,000,000 years and analyzed with a goal to understanding periodic and quasi-periodic patterns in global temperature change superimposed on a “background” average temperature change. Quasi-periodic signatures were identified that predate the Industrial Revolution, during much of which direct data on temperature are not available. These data indicate that Earth temperatures have undergone a number of periodic and quasi-periodic intervals that contain both global warming and global cooling cycles. The fluctuations are superimposed on a background of temperature change that has a declining slope during the two periods, pre-ice age and post ice age with a transition about 12,000 BCE. The data are divided into “events” that span the time periods 3,000,000 BCE to “0” CE, 1,000,000 BCE to “0” CE, 12,000 BCE to 2,000 CE and 2,000 BCE to 2,000 CE. An equation using a quasi-periodic (frequency modulated sine waves) patterns was developed to analyze the date sets for quasi-periodic patterns. “Periodicities” which show reasonable agreement with the predictions of Milankovitch and other investigators were found in the data sets.

  7. The Physics of the Cosmic Microwave Background

    International Nuclear Information System (INIS)

    Peacock, John

    2007-01-01

    The award of the 2006 Nobel Prize for Physics is a reminder to non-specialists that the cosmic microwave background (CMB) has yielded astonishing advances in our understanding of cosmology. Mather and Smoot received their prize for work done with NASA's COBE satellite in the early 1990s, but the subject has if anything accelerated since then. The results from NASA's WMAP satellite, reported in 2003 and 2006, have proved COBE's equal in importance and have generated huge worldwide interest. There could therefore hardly be a better time to be writing a detailed textbook to explain what the fuss is all about to a new generation of research students. A comprehensive treatment of the physics of the CMB is not easy to achieve, because it is connected to so much else in cosmology. A student must have a background knowledge of the geometry and dynamics of an expanding universe, plus a deep exposure to the physics of quantum fields, in order to understand the modern 'inflationary' view in which the universe was set expanding by the tension of the vacuum, and was seeded with small inhomogeneities as a result of quantum fluctuations. Although the theory of inflation is not yet verified, the CMB has the potential to accomplish this; testing inflation is undoubtedly one of the principal aims of cosmology over the next decade. Even with this preparation, understanding the properties of the CMB is quite hard at the professional level, requiring the perturbation expansion of the relativistic Boltzmann equation. These technical difficulties are particularly strong in the frontier area of CMB polarization. Naselsky and his collaborators have allocated themselves a relatively brief 255 pages in which to meet these challenges, so some compromise is inevitable. Although the preface is not explicit about the assumed prior knowledge, no systematic material on background cosmology or on inflation is to be found. The former is reasonable in a graduate-level text (which this certainly is

  8. Axiological Background of Vietnamese Students Adaptability

    Directory of Open Access Journals (Sweden)

    Сергей Иванович Кудинов

    2018-12-01

    the same time the representatives of the vocational and career axiological orientation type were more successful in adaptability, as compared to other groups. The students with egocentric orientation turned out less successful in adaptability. They are distinguished by the highest severity of negative background mood, uncertainty, difficulties in communication. As a conclusion, we defined the role of axiological orientation as the primary predictor of personal adaptability in multicultural environment.

  9. Socialcultural background of formation of classical metaphysics

    Directory of Open Access Journals (Sweden)

    I. Z. Derzhko

    2014-09-01

    Full Text Available The classical model of philosophy has shaped ideas about its nature and aims that were laid in ancient metaphysics, but have been substantially amended by civilizational change. Socialcultural background of philosophy became trends that began to emerge in late medieval culture has particularly flourished there during modern times. Sphere of existence is important for the development of any spiritual phenomenon. For metaphysics it is the idea of humanity, acting as a kind of cultural protest against the domination of religion. This caused criticism of the medieval way of life and thinking. The idea of human revival based on spirit of antiquity has grounded. Disclaimer theological philosophy medieval variant type is as opposed to free philosophizing, coupled with poetry and literature, University dogmatic philosophy. There were a «rediscovery» of Plato, Aristotle reinterpretation. Philosophers explored a problem of human emotions and relationships, considering the person as a whole being, which is inherent in the mind, which cannot be considered without bodily desires and emotions. Change of the values awakened activity of the human person, led its transformation settings concerning himself and the surrounding world. Thus objectively obtained expression and ideological embodiment of civilization in a need of a new type of man - to a much greater extent compared to medieval activity, initiative, freedom, rationality, responsibility. Under the influence of such attitudes changes within religion gradually took place. Through the efforts of thinkers like Luther, Calvin, Munzer there were laid ideas of the Reformation that go far beyond its borders, gaining general cultural nature. The Church was increasingly losing control over everyday human existence. Gradually standards of a free, relaxed life became conventional; requirements of the body, «earthly» spirit demands fulfilling played a huge role. Thought and Culture of the Renaissance reflects

  10. Spacetime Dynamics and Slow Neutrino Background

    Science.gov (United States)

    Zhang, Tianxi

    2018-06-01

    Space is a form of existence of matter, while time is a measure of change of the matter in the space. Issac Newton suggested that the space and time are absolute, not affected by matter and its motion. His first law of motion or the law of inertia says that, without net force acts on it, an object in motion remains the motion in a straight line at a constant speed. Ernest Mach proposed that the inertia of a body results from the gravitational interaction on the body by the rest of the entire universe. As mass is a measure of inertia, Mach’s principle can be simply stated as mass here is affected by matter there. On the basis of Mach’s principle, Albert Einstein considered the space and time to be relative and developed two theories of relativities. One called special relativity describes the effect of motion on spacetime and the other called general relativity describes the effect of matter on spacetime. Recently, the author has further considered reactions of the influenced spacetime on the moving objects, including photons. A moving object including a photon, because of its continuously keeping on displacement, disturbs the rest of the entire universe or distorts/curves the spacetime. The distorted or curved spacetime then generates an effective gravitational force to act back on the moving object or photon, so that reduces the object inertia or photon frequency. Considering the disturbance of spacetime by a photon is extremely weak, the author has modelled the effective gravitational force to be Newtonian and derived a new redshift-distance relation that not only perfectly explained the redshift-distance measurement of distant type Ia supernovae but also inherently obtained Hubble’s law as an approximate at small redshift. In this study, we will further analyse the reaction of the influenced spacetime on moving neutrinos and demonstrate the creation of slow neutrino (or tired neutrino) background that may be gravitationally orbiting around clusters

  11. Visual signal detection in structured backgrounds. II. Effects of contrast gain control, background variations, and white noise

    Science.gov (United States)

    Eckstein, M. P.; Ahumada, A. J. Jr; Watson, A. B.

    1997-01-01

    Studies of visual detection of a signal superimposed on one of two identical backgrounds show performance degradation when the background has high contrast and is similar in spatial frequency and/or orientation to the signal. To account for this finding, models include a contrast gain control mechanism that pools activity across spatial frequency, orientation and space to inhibit (divisively) the response of the receptor sensitive to the signal. In tasks in which the observer has to detect a known signal added to one of M different backgrounds grounds due to added visual noise, the main sources of degradation are the stochastic noise in the image and the suboptimal visual processing. We investigate how these two sources of degradation (contrast gain control and variations in the background) interact in a task in which the signal is embedded in one of M locations in a complex spatially varying background (structured background). We use backgrounds extracted from patient digital medical images. To isolate effects of the fixed deterministic background (the contrast gain control) from the effects of the background variations, we conduct detection experiments with three different background conditions: (1) uniform background, (2) a repeated sample of structured background, and (3) different samples of structured background. Results show that human visual detection degrades from the uniform background condition to the repeated background condition and degrades even further in the different backgrounds condition. These results suggest that both the contrast gain control mechanism and the background random variations degrade human performance in detection of a signal in a complex, spatially varying background. A filter model and added white noise are used to generate estimates of sampling efficiencies, an equivalent internal noise, an equivalent contrast-gain-control-induced noise, and an equivalent noise due to the variations in the structured background.

  12. Marginalne skupine u prometu - osnovni aspekti i podaci

    Directory of Open Access Journals (Sweden)

    Zlatko Hinšt

    2012-10-01

    Full Text Available The paper deals with identifying some marginal groups in traffic (children, senior citizens, disabled persons and other risk groups and provides data on their share in the total number of Zagreb inhabitants in conjunction with some aspects of traffic trauma and safety. The author first discusses the sociological definition of the term of marginal group within a wider scope of viewing the matter, and then refers to respective approaches of traffic, engineering and medical science. In conclusion the paper provides a concise review of the existing and required practical propositions in traffic and the need for their wider-scope (redefined concept.

  13. Genderové aspekty rozchodu manželství

    Czech Academy of Sciences Publication Activity Database

    Dudová, Radka

    2004-01-01

    Roč. 5, č. 4 (2004), s. 9-10 ISSN 1213-0028 R&D Projects: GA AV ČR IBS7028002 Institutional research plan: CEZ:AV0Z7028912 Keywords : divorce * division of domestic labour * custody Subject RIV: AO - Sociology, Demography

  14. Otroctví a jeho novodobé aspekty

    OpenAIRE

    Kokešová, Lucie

    2016-01-01

    1 Abstract Slavery and its modern aspects This diploma thesis deals with the current and controversial topic. Aim of this thesis is to put attention to the speeches, forms and incredible frequency of modern slavery - phenomenon that would be at first glance wrongly seen as just historical issue. First chapter of the thesis speaks about historical excursion of slavery. Because of the limited scope is history focused on the main areas of ancient Greece and Rome, the area of the American contine...

  15. Teoreticheskie aspekty prigranichnogo jekonomicheskogo sotrudnichestva na osnove integracionnyh processov

    Directory of Open Access Journals (Sweden)

    Bilchak V.

    2014-08-01

    Full Text Available In this article the author analyses theoretical aspects of border economy in the conditions of modern processes of integration. The author describes the existing schools and concepts of integration stressing the role of government regulation relating to the deformations in the development of the world economic mechanism. Modern studies focus on the evolution of integration processes, which has largely affected the key elements of the world economic mechanism from classical political economy, monopoly regulation. This resulted in monopolistic competition, imperfect competition, and oligopoly – largely, through all fields and poles of economic growth to certain elements of government regulation and social reproduction on the international scale. The author examines the key elements and stages of economic integration. These stages assume a number of consecutive forms: free trade zone, customs union, common market, complete economic integration, and economic union. The article shows that the transition occurs from the lowest to the highest stages — from the processes of integration involving, firstly, trade market and then capital and labour markets to the integration of social sphere. The theoretical aspects of all these transformations can be easily traced in the case of EU integration processes.

  16. Sociální aspekty a legalizace prostituce

    OpenAIRE

    JEDLIČKOVÁ, Veronika

    2017-01-01

    The issue of prostitution is still as relevant nowadays as it was in ancient times, when this activity had first been documented. Prostitution has been perceived in various ways in different times and countries. At present, prostitution is legalised in some countries, but with many illegal and criminal activities associated to it (e.g. drug problems, illegal restraint, blackmailing). In the Czech Republic there are no legal regulations regarding this activity, therefor we're referring to a le...

  17. Negativní aspekty nasazování ICT

    OpenAIRE

    Weinsteinová, Adéla

    2013-01-01

    This diploma thesis exmines the negative aspects of using information and communication technologies. The main attention is fosused on virtual reality, especially 3D projection in order to decide wheather the using of it has negative impact on phycal and psychological state of the user or not, which exactly are these impacts and what probably cause them. This first part is dedicated to expain concept and history of ICT, explonation of the multidimensional princip and content of each dimension...

  18. Społeczne aspekty problemu rozwodów

    OpenAIRE

    Rosset, Edward

    1981-01-01

    At the very beginning the author declares himself against divorces. He does not mind legal institution of divorce, which is considered as indispensable, but disorganization of family life that leads to a divorce. Among the sources of growing phenomenon of family disintegration in contemporary world rash decisions of family setting up and the lack of responsibility for a family are mentioned. The author discusses divorces effects too, and among them: permanently growing number of „orphans afte...

  19. Wybrane aspekty adaptacji kulturowej testów neuropsychologicznych

    Directory of Open Access Journals (Sweden)

    Anna Marcinkowska

    2017-11-01

    Full Text Available Wyniki testów neuropsychologicznych są zależne od wykształcenia osoby badanej, jej umiejętności czytania i pisania, ale również pochodzenia etnicznego i tradycji kulturowych. Dlatego do największych wyzwań neuropsychologii XXI wieku należy stworzenie metody diagnostycznej umożliwiającej pomiar danego aspektu procesu poznawczego bez względu na poziom wykształcenia i pochodzenie pacjenta. Celem pracy jest ukazanie przykładowych problemów kulturowych związanych z adaptacją testów neuropsychologicznych ukierunkowaną na możliwość ich zastosowania w innym kręgu kulturowym. Problemy trafności kulturowej pomiaru testowego dotyczą samych zadań testowych, ich treści, ale też kontekstu badania. W niektórych kulturach niezachodnich testowanie psychometryczne jest nieodpowiednie, gdyż sama sytuacja badania testowego nie należy tam do typowych. Testy funkcji poznawczych zazwyczaj wymagają nie tylko opracowania norm specyficznych dla danej kultury, lecz także kulturowej adaptacji zadań. Próby wzrokowe uważane są za mniej obciążone kulturowo niż próby słowne, jednak wyniki niektórych testów mogą być bardzo zależne od wiedzy semantycznej. Podobny problem dotyczy testów praksji – wykonanie czy naśladowanie gestu zależy od jego znajomości i obecności w kulturze. Adaptując zadania pamięciowe, szczególnie zaś testy pamięci logicznej, w celu zastosowania ich w  innym kręgu kulturowym, należy zadbać o  to, aby materiał miał podobne znaczenie dla osób badanych. Adaptacja testów funkcji wykonawczych, z racji zaangażowania bardziej podstawowych procesów (funkcji językowych, wzrokowo-przestrzennych, praksji i pamięci, wymaga uwzględnienia wszystkich wymienionych czynników. Ponadto, z uwagi na wpływ kultury na strategie rozwiązywania problemów, niektóre zadania mogą być nieodpowiednie w innych kręgach kulturowych nie tyle z powodu treści, ile konstrukcji problemu. Tworzenie metod oceny funkcji poznawczych do zastosowania w różnych kręgach kulturowych, w tym metod przesiewowych, jest bardzo trudne. Dalsze badania powinny się koncentrować na opracowywaniu narzędzi dostosowanych do konkretnych kontekstów kulturowych i opartych na właściwym zrozumieniu populacji, do których są kierowane.

  20. Sociální aspekty tvořivosti

    Czech Academy of Sciences Publication Activity Database

    Veselý, Arnošt

    2006-01-01

    Roč. 4, č. 7 (2006), s. 5-7 ISSN 1214-1720 R&D Projects: GA MPS(CZ) 1J/005/04-DP2 Institutional research plan: CEZ:AV0Z70280505 Keywords : creativity * system model * field Subject RIV: AO - Sociology, Demography www.socioweb.cz

  1. Bioētikas krimināltiesiskie aspekti

    OpenAIRE

    Lisovskis, Jānis

    2011-01-01

    Šis darbs ir veltīts nozīmīgu bioētikas jautājumu aplūkošanai saistība ar krimināltiesībām, precīzāk, ģenētiskās inženierijas saistību ar Krimināllikumu. Straujā attīstība tādās zinātnes nozarēs kā nanotehnoloģijas, ģenētiskā inženierija, manipulācijas ar audiem un cilmes šūnām, kā arī citās ar šīm saistītās biomedicīnas nozarēs rada jaunu problēmu riskus, proti, robežu noteikšana, cik tālu zinātne var sniegties. Lai gan modernajiem atklājumiem medicīnā ir ļoti liels potenciāls uzlabo...

  2. Reumatoidalne zapalenie stawów – aspekty immunobiologiczne

    Directory of Open Access Journals (Sweden)

    Stefan Mackiewicz

    2011-08-01

    Full Text Available W trakcie ewolucji następują zmiany, których konsekwencją jestpowstanie wielu układów molekularnych determinujących przebiegchoroby. Pojawienie się reumatoidalnego zapalenia stawów(RZS jest uwarunkowane licznymi genami wrażliwości na chorobę.Czynniki środowiskowe modyfikują genom i stanowią impulsdo inicjacji choroby. Proces zapalny w RZS jest bardzo złożonyw wyniku interakcji komórki–geny–cząsteczki. Powstającyw przepływie sygnałów „chaos biologiczny” prowadzi do przekroczeniagranicy homeostazy i następstw patologicznych (ryc. 1.Mechanizmy obrony są słabo wykształcone. Dotychczasoweleczenie modyfikujące wpływa na obniżenie reaktywności biologicznejaktywnych komórek.

  3. Economic aspects of radiosterilization; Aspekty ekonomiczne sterylizacji radiacyjnej

    Energy Technology Data Exchange (ETDEWEB)

    Zimek, Z [Institute of Nuclear Chemistry and Technology, Warsaw (Poland)

    1997-10-01

    The economic analysis of radiosterilization have been done. The costs have been estimated on the example of Electron Accelerator Irradiation Plant for Radiosterilization working in Institute of Nuclear Chemistry and Technology, Warsaw. 3 tabs.

  4. The effect of background music in auditory health persuasion

    NARCIS (Netherlands)

    Elbert, Sarah; Dijkstra, Arie

    2013-01-01

    In auditory health persuasion, threatening information regarding health is communicated by voice only. One relevant context of auditory persuasion is the addition of background music. There are different mechanisms through which background music might influence persuasion, for example through mood

  5. Demonstration of Cosmic Microwave Background Delensing Using the Cosmic Infrared Background.

    Science.gov (United States)

    Larsen, Patricia; Challinor, Anthony; Sherwin, Blake D; Mak, Daisy

    2016-10-07

    Delensing is an increasingly important technique to reverse the gravitational lensing of the cosmic microwave background (CMB) and thus reveal primordial signals the lensing may obscure. We present a first demonstration of delensing on Planck temperature maps using the cosmic infrared background (CIB). Reversing the lensing deflections in Planck CMB temperature maps using a linear combination of the 545 and 857 GHz maps as a lensing tracer, we find that the lensing effects in the temperature power spectrum are reduced in a manner consistent with theoretical expectations. In particular, the characteristic sharpening of the acoustic peaks of the temperature power spectrum resulting from successful delensing is detected at a significance of 16σ, with an amplitude of A_{delens}=1.12±0.07 relative to the expected value of unity. This first demonstration on data of CIB delensing, and of delensing techniques in general, is significant because lensing removal will soon be essential for achieving high-precision constraints on inflationary B-mode polarization.

  6. The psychological background about human error and safety in NPP

    International Nuclear Information System (INIS)

    Zhang Li

    1992-01-01

    A human error is one of the factors which cause an accident in NPP. The in-situ psychological background plays an important role in inducing it. The author analyzes the structure of one's psychological background when one is at work, and gives a few examples of typical psychological background resulting in human errors. Finally it points out that the fundamental way to eliminate the unfavourable psychological background of safety production is to establish the safety culture in NPP along with its characteristics

  7. Direction Dependent Background Fitting for the Fermi GBM Data

    OpenAIRE

    Szécsi, Dorottya; Bagoly, Zsolt; Kóbori, József; Horváth, István; Balázs, Lajos G.

    2013-01-01

    We present a method for determining the background of Fermi GBM GRBs using the satellite positional information and a physical model. Since the polynomial fitting method typically used for GRBs is generally only indicative of the background over relatively short timescales, this method is particularly useful in the cases of long GRBs or those which have Autonomous Repoint Request (ARR) and a background with much variability on short timescales. We give a Direction Dependent Background Fitting...

  8. George Smoot, Blackbody, and Anisotropy of the Cosmic Microwave Background

    Science.gov (United States)

    the Cosmic Microwave Background Radiation Resources with Additional Information * Videos 'George Smoot anisotropy of the cosmic microwave background radiation." '1 Smoot previously won the Ernest Orlando . Smoot, blackbody, and anisotropy of the Cosmic Microwave Background (CMB) radiation is available in full

  9. Background removal in X-ray fiber diffraction patterns

    International Nuclear Information System (INIS)

    Millane, R.P.; Arnott, S.

    1985-01-01

    Background can be a major source of error in measurement of diffracted intensities in fiber diffraction patterns. Errors can be large when poorly oriented less-crystalline specimens give diffraction patterns with little uncontaminated background. A method for estimating and removing a general global background in such cases is described and illustrated with an example. (orig.)

  10. Research on background neutron of 226Ra γ source

    International Nuclear Information System (INIS)

    Ji Changsong

    1996-01-01

    This work studies the background neutron emission of 226 Ra γ source: the mechanism of resulting in background neutron is studied; a thesis that the (α, n) type reaction on Radium carriers Cl or Br is the main source of creating background neutron emission of 226 Ra γ source has been proposed and certificated; a proposal of substitution of Cl carrier by Br in radium source produced in China in order to reduce background neutron emission is put forward. A result to reduce the background neutron from 96.4 neutrons/4πsmgRa to 6.1 neutrons/4πsmgRa is obtained

  11. Judgments of aircraft noise in a traffic noise background

    Science.gov (United States)

    Powell, C. A.; Rice, C. G.

    1975-01-01

    An investigation was conducted to determine subjective response to aircraft noise in different road traffic backgrounds. In addition, two laboratory techniques for presenting the aircraft noise with the background noise were evaluated. For one technique, the background noise was continuous over an entire test session; for the other, the background noise level was changed with each aircraft noise during a session. Subjective response to aircraft noise was found to decrease with increasing background noise level, for a range of typical indoor noise levels. Subjective response was found to be highly correlated with the Noise Pollution Level (NPL) measurement scale.

  12. The Anisotropy of the Microwave Background to l=3500: Mosaic Observations with the Cosmic Background Imager

    Science.gov (United States)

    Pearson, T. J.; Mason, B. S.; Readhead, A. C. S.; Shepherd, M. C.; Sievers, J. L.; Udomprasert, P. S.; Cartwright, J. K.; Farmer, A. J.; Padin, S.; Myers, S. T.; hide

    2002-01-01

    Using the Cosmic Background Imager, a 13-element interferometer array operating in the 26-36 GHz frequency band, we have observed 40 deg (sup 2) of sky in three pairs of fields, each approximately 145 feet x 165 feet, using overlapping pointings: (mosaicing). We present images and power spectra of the cosmic microwave background radiation in these mosaic fields. We remove ground radiation and other low-level contaminating signals by differencing matched observations of the fields in each pair. The primary foreground contamination is due to point sources (radio galaxies and quasars). We have subtracted the strongest sources from the data using higher-resolution measurements, and we have projected out the response to other sources of known position in the power-spectrum analysis. The images show features on scales approximately 6 feet-15 feet, corresponding to masses approximately 5-80 x 10(exp 14) solar mass at the surface of last scattering, which are likely to be the seeds of clusters of galaxies. The power spectrum estimates have a resolution delta l approximately 200 and are consistent with earlier results in the multipole range l approximately less than 1000. The power spectrum is detected with high signal-to-noise ratio in the range 300 approximately less than l approximately less than 1700. For 1700 approximately less than l approximately less than 3000 the observations are consistent with the results from more sensitive CBI deep-field observations. The results agree with the extrapolation of cosmological models fitted to observations at lower l, and show the predicted drop at high l (the "damping tail").

  13. Modulation of the Object/Background Interaction by Spatial Frequency

    Directory of Open Access Journals (Sweden)

    Yanju Ren

    2011-05-01

    Full Text Available With regard to the relationship between object and background perception in the natural scene images, functional isolation hypothesis and interactive hypothesis were proposed. Based on previous studies, the present study investigated the role of spatial frequency in the relationship between object and background perception in the natural scene images. In three experiments, participants reported the object, background, or both after seeing each picture for 500 ms followed by a mask. The authors found that (a backgrounds were identified more accurately when they contained a consistent rather than an inconsistent object, independently of spatial frequency; (b objects were identified more accurately in a consistent than an inconsistent background under the condition of low spatial frequencies but not high spatial frequencies; (c spatial frequency modulation remained when both objects and backgrounds were reported simultaneously. The authors conclude that object/background interaction is partially dependent on spatial frequency.

  14. Status of the Simbol-X Background Simulation Activities

    Science.gov (United States)

    Tenzer, C.; Briel, U.; Bulgarelli, A.; Chipaux, R.; Claret, A.; Cusumano, G.; Dell'Orto, E.; Fioretti, V.; Foschini, L.; Hauf, S.; Kendziorra, E.; Kuster, M.; Laurent, P.; Tiengo, A.

    2009-05-01

    The Simbol-X background simulation group is working towards a simulation based background and mass model which can be used before and during the mission. Using the Geant4 toolkit, a Monte-Carlo code to simulate the detector background of the Simbol-X focal plane instrument has been developed with the aim to optimize the design of the instrument. Achieving an overall low instrument background has direct impact on the sensitivity of Simbol-X and thus will be crucial for the success of the mission. We present results of recent simulation studies concerning the shielding of the detectors with respect to the diffuse cosmic hard X-ray background and to the cosmic-ray proton induced background. Besides estimates of the level and spectral shape of the remaining background expected in the low and high energy detector, also anti-coincidence rates and resulting detector dead time predictions are discussed.

  15. Effects of background music on concentration of workers.

    Science.gov (United States)

    Huang, Rong-Hwa; Shih, Yi-Nuo

    2011-01-01

    Background music is a common element in daily living and the workplace. Determination of whether background music affects human work concentration is a relevant concern. Studies have found background music influences human behavior, and this study attempts to understand how background music and listener fondness for types of music affects worker concentration. This study analyzes how different types of background music--and how listeners' degree of preference for the background music--can affect listener concentration in attention testing through Randomized Controlled Trial (RCT). Data were collected from 89 workers. The participants ranged in age between 19 and 28 years old, with an average age of 24 years old. We conclude background music influenced listener attention. This influence has more to do with listener fondness for the music than with type of music. Compared to situations without background music, the likelihood of background music affecting test-taker attention performance is likely to increase with the degree to which the test-taker likes or dislikes the music. It is important not to select music that workers strongly like or dislike when making a selection of background music to avoid negatively affecting worker concentration.

  16. A COSMIC MICROWAVE BACKGROUND LENSING MASS MAP AND ITS CORRELATION WITH THE COSMIC INFRARED BACKGROUND

    Energy Technology Data Exchange (ETDEWEB)

    Holder, G. P.; De Haan, T.; Dobbs, M. A.; Dudley, J. [Department of Physics, McGill University, Montreal, Quebec H3A 2T8 (Canada); Viero, M. P.; Bock, J. [California Institute of Technology, Pasadena, CA 91125 (United States); Zahn, O. [Berkeley Center for Cosmological Physics, Department of Physics, University of California, and Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Aird, K. A. [University of Chicago, Chicago, IL 60637 (United States); Benson, B. A.; Bhattacharya, S.; Bleem, L. E.; Carlstrom, J. E.; Chang, C. L.; Crawford, T. M.; Crites, A. T. [Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637 (United States); Brodwin, M. [Department of Physics and Astronomy, University of Missouri, Kansas City, MO 64110 (United States); Cho, H-M. [NIST Quantum Devices Group, Boulder, CO 80305 (United States); Conley, A. [Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, CO 80309 (United States); George, E. M. [Department of Physics, University of California, Berkeley, CA 94720 (United States); Halverson, N. W. [Department of Astrophysical and Planetary Sciences and Department of Physics, University of Colorado, Boulder, CO 80309 (United States); and others

    2013-07-01

    We use a temperature map of the cosmic microwave background (CMB) obtained using the South Pole Telescope at 150 GHz to construct a map of the gravitational convergence to z {approx} 1100, revealing the fluctuations in the projected mass density. This map shows individual features that are significant at the {approx}4{sigma} level, providing the first image of CMB lensing convergence. We cross-correlate this map with Herschel/SPIRE maps covering 90 deg{sup 2} at wavelengths of 500, 350, and 250 {mu}m. We show that these submillimeter (submm) wavelength maps are strongly correlated with the lensing convergence map, with detection significances in each of the three submm bands ranging from 6.7{sigma} to 8.8{sigma}. We fit the measurement of the cross power spectrum assuming a simple constant bias model and infer bias factors of b = 1.3-1.8, with a statistical uncertainty of 15%, depending on the assumed model for the redshift distribution of the dusty galaxies that are contributing to the Herschel/SPIRE maps.

  17. Cosmic gamma-ray background radiation. Current understandings and problems

    International Nuclear Information System (INIS)

    Inoue, Yoshiyuki

    2015-01-01

    The cosmic gamma-ray background radiation is one of the most fundamental observables in the gamma-ray band. Although the origin of the cosmic gamma-ray background radiation has been a mystery for a long time, the Fermi gamma-ray space telescope has recently measured it at 0.1-820 GeV and revealed that the cosmic GeV gamma-ray background is composed of blazars, radio galaxies, and star-forming galaxies. However, Fermi still leaves the following questions. Those are dark matter contribution, origins of the cosmic MeV gamma-ray background, and the connection to the IceCube TeV-PeV neutrino events. In this proceeding, I will review the current understandings of the cosmic gamma-ray background and discuss future prospects of cosmic gamma-ray background radiation studies. (author)

  18. Overcoming High Energy Backgrounds at Pulsed Spallation Sources

    CERN Document Server

    Cherkashyna, Nataliia; DiJulio, Douglas D.; Khaplanov, Anton; Pfeiffer, Dorothea; Scherzinger, Julius; Cooper-Jensen, Carsten P.; Fissum, Kevin G.; Ansell, Stuart; Iverson, Erik B.; Ehlers, Georg; Gallmeier, Franz X.; Panzner, Tobias; Rantsiou, Emmanouela; Kanaki, Kalliopi; Filges, Uwe; Kittelmann, Thomas; Extegarai, Maddi; Santoro, Valentina; Kirstein, Oliver; Bentley, Phillip M.

    2015-01-01

    Instrument backgrounds at neutron scattering facilities directly affect the quality and the efficiency of the scientific measurements that users perform. Part of the background at pulsed spallation neutron sources is caused by, and time-correlated with, the emission of high energy particles when the proton beam strikes the spallation target. This prompt pulse ultimately produces a signal, which can be highly problematic for a subset of instruments and measurements due to the time-correlated properties, and different to that from reactor sources. Measurements of this background have been made at both SNS (ORNL, Oak Ridge, TN, USA) and SINQ (PSI, Villigen, Switzerland). The background levels were generally found to be low compared to natural background. However, very low intensities of high-energy particles have been found to be detrimental to instrument performance in some conditions. Given that instrument performance is typically characterised by S/N, improvements in backgrounds can both improve instrument pe...

  19. Effects of Face and Background Color on Facial Expression Perception

    Directory of Open Access Journals (Sweden)

    Tetsuto Minami

    2018-06-01

    Full Text Available Detecting others’ emotional states from their faces is an essential component of successful social interaction. However, the ability to perceive emotional expressions is reported to be modulated by a number of factors. We have previously found that facial color modulates the judgment of facial expression, while another study has shown that background color plays a modulatory role. Therefore, in this study, we directly compared the effects of face and background color on facial expression judgment within a single experiment. Fear-to-anger morphed faces were presented in face and background color conditions. Our results showed that judgments of facial expressions was influenced by both face and background color. However, facial color effects were significantly greater than background color effects, although the color saturation of faces was lower compared to background colors. These results suggest that facial color is intimately related to the judgment of facial expression, over and above the influence of simple color.

  20. The determination and use of radionuclide background in gamma spectrometry

    International Nuclear Information System (INIS)

    Zimmer, W.H.

    1986-01-01

    Background is the major component of gross photon peak area. Therefore, net area, nuclide activity, counting uncertainty, and limits of detection calculations are no better than the calculation of background. In this study, background in gamma spectrometry is explored in several of its aspects. Means are presented to reduce background. Standard practices are presented to be used in the acquisition of valid, relevant background data. Unified standard calculations with examples are presented in the use of background data to determine net count and counting uncertainty. L. A. Currie's latest calculations of Lower Limits of Detection (1) (LLD) as they apply to gamma spectrometry are reviewed. Finally, Maximum Undetected Activity (MUA), LLD, and Critical Level (CL) concepts and calculations are compared in sample spectra

  1. Absolute calibration and beam background of the Squid Polarimeter

    International Nuclear Information System (INIS)

    Blaskiewicz, M.M.; Cameron, P.R.; Shea, T.J.

    1996-01-01

    The problem of beam background in Squid Polarimetry is not without residual benefits. The authors may deliberately generate beam background by gently kicking the beam at the spin tune frequency. This signal may be used to accomplish a simple and accurate absolute calibration of the polarimeter. The authors present details of beam background calculations and their application to polarimeter calibration, and suggest a simple proof-of-principle accelerator experiment

  2. Maxwell-Chern-Simons theory for curved spacetime backgrounds

    International Nuclear Information System (INIS)

    Kant, E.; Klinkhamer, F.R.

    2005-01-01

    We consider a modified version of four-dimensional electrodynamics, which has a photonic Chern-Simons-like term with spacelike background vector in the action. Light propagation in curved spacetime backgrounds is discussed using the geometrical-optics approximation. The corresponding light path is modified, which allows for new effects. In a Schwarzschild background, for example, there now exist stable bounded orbits of light rays and the two polarization modes of light rays in unbounded orbits can have different gravitational redshifts

  3. Cosmological Backgrounds of Gravitational Waves and eLISA

    OpenAIRE

    Dufaux, Jean-Francois

    2012-01-01

    We review cosmological backgrounds of gravitational waves with a particular attention to the scientific potential of the eLISA/NGO mission. After an overview of cosmological backgrounds and detectors, we consider different cosmological sources that could lead to an observable signal. We then study the backgrounds produced by first-order phase transitions and networks of cosmic strings, assessing the prospects for their detection.

  4. The Background-Field Method and Noninvariant Renormalization

    International Nuclear Information System (INIS)

    Avdeev, L.V.; Kazakov, D.I.; Kalmykov, M.Yu.

    1994-01-01

    We investigate the consistency of the background-field formalism when applying various regularizations and renormalization schemes. By an example of a two-dimensional σ model it is demonstrated that the background-field method gives incorrect results when the regularization (and/or renormalization) is noninvariant. In particular, it is found that the cut-off regularization and the differential renormalization belong to this class and are incompatible with the background-field method in theories with nonlinear symmetries. 17 refs

  5. Radiation background with the CMS RPCs at the LHC

    CERN Document Server

    Costantini, Silvia; Cai, J.; Li, Q.; Liu, S.; Qian, S.; Wang, D.; Xu, Z.; Zhang, F.; Choi, Y.; Goh, J.; Kim, D.; Choi, S.; Hong, B.; Kang, J.W.; Kang, M.; Kwon, J.H.; Lee, K.S.; Lee, S.K.; Park, S.K.; Pant, L.M.; Mohanty, A.K.; Chudasama, R.; Singh, J.B.; Bhatnagar, V.; Mehta, A.; Kumar, R.; Cauwenbergh, S.; Cimmino, A.; Crucy, S.; Fagot, A.; Garcia, G.; Ocampo, A.; Poyraz, D.; Salva, S.; Thyssen, F.; Tytgat, M.; Zaganidis, N.; Doninck, W.V.; Cabrera, A.; Chaparro, L.; Gomez, J.P.; Gomez, B.; Sanabria, J.C.; Avila, C.; Ahmad, A.; Muhammad, S.; Shoaib, M.; Hoorani, H.; Awan, I.; Ali, I.; Ahmed, W.; Asghar, M.I.; Shahzad, H.; Sayed, A.; Ibrahim, A.; Aly, S.; Assran, Y.; Radi, A.; Elkafrawy, T.; Sharma, A.; Colafranceschi, S.; Abbrescia, M.; Calabria, C.; Colaleo, A.; Iaselli, G.; Loddo, F.; Maggi, M.; Nuzzo, S.; Pugliese, G.; Radogna, R.; Venditti, R.; Verwilligen, P.; Benussi, L.; Bianco, S.; Piccolo, D.; Paolucci, P.; Buontempo, S.; Cavallo, N.; Merola, M.; Fabozzi, F.; Iorio, O.M.; Braghieri, A.; Montagna, P.; Riccardi, C.; Salvini, P.; Vitulo, P.; Vai, I.; Magnani, A.; Dimitrov, A.; Litov, L.; Pavlov, B.; Petkov, P.; Aleksandrov, A.; Genchev, V.; Iaydjiev, P.; Rodozov, M.; Sultanov, G.; Vutova, M.; Stoykova, S.; Hadjiiska, R.; Ibargüen, H.S.; Morales, M.I.P.; Bernardino, S.C.; Bagaturia, I.; Tsamalaidze, Z.; Crotty, I.; Kim, M.S.

    2015-05-28

    The Resistive Plate Chambers (RPCs) are employed in the CMS experiment at the LHC as dedicated trigger system both in the barrel and in the endcap. This note presents results of the radiation background measurements performed with the 2011 and 2012 proton-proton collision data collected by CMS. Emphasis is given to the measurements of the background distribution inside the RPCs. The expected background rates during the future running of the LHC are estimated both from extrapolated measurements and from simulation.

  6. Uncertain Portfolio Selection with Background Risk and Liquidity Constraint

    Directory of Open Access Journals (Sweden)

    Jia Zhai

    2017-01-01

    Full Text Available This paper discusses an uncertain portfolio selection problem with consideration of background risk and asset liquidity. In addition, the transaction costs are also considered. The security returns, background asset return, and asset liquidity are estimated by experienced experts instead of historical data. Regarding them as uncertain variables, a mean-risk model with background risk, liquidity, and transaction costs is proposed for portfolio selection and the crisp forms of the model are provided when security returns obey different uncertainty distributions. Moreover, for better understanding of the impact of background risk and liquidity on portfolio selection, some important theorems are proved. Finally, numerical experiments are presented to illustrate the modeling idea.

  7. Background noise of acoustic emission signals in sodium piping loop

    International Nuclear Information System (INIS)

    Mori, Y.; Aoki, K.; Kuribayashi, K.; Kishi, T.; Sakakibara, Y.

    1985-01-01

    Background noise measurement in the frequency range of acoustic emission (AE) signals was made on the sodium piping loops of a 50 MW steam generator test facility in the Power Reactor and Nuclear Fuel Development Corporation (PNC). During the dynamic characteristics test of the steam generator over a wide range of operating conditions, the background noise generated on the pipe surface was measured using wideband AE sensor externally mounted with waveguide. Data were obtained for the effect of power loads of steam generator on both amplitude and frequency spectra of background noise signals. Source and nature of background noise were established

  8. A model independent safeguard against background mismodeling for statistical inference

    Energy Technology Data Exchange (ETDEWEB)

    Priel, Nadav; Landsman, Hagar; Manfredini, Alessandro; Budnik, Ranny [Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Herzl St. 234, Rehovot (Israel); Rauch, Ludwig, E-mail: nadav.priel@weizmann.ac.il, E-mail: rauch@mpi-hd.mpg.de, E-mail: hagar.landsman@weizmann.ac.il, E-mail: alessandro.manfredini@weizmann.ac.il, E-mail: ran.budnik@weizmann.ac.il [Teilchen- und Astroteilchenphysik, Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany)

    2017-05-01

    We propose a safeguard procedure for statistical inference that provides universal protection against mismodeling of the background. The method quantifies and incorporates the signal-like residuals of the background model into the likelihood function, using information available in a calibration dataset. This prevents possible false discovery claims that may arise through unknown mismodeling, and corrects the bias in limit setting created by overestimated or underestimated background. We demonstrate how the method removes the bias created by an incomplete background model using three realistic case studies.

  9. Background-Modeling-Based Adaptive Prediction for Surveillance Video Coding.

    Science.gov (United States)

    Zhang, Xianguo; Huang, Tiejun; Tian, Yonghong; Gao, Wen

    2014-02-01

    The exponential growth of surveillance videos presents an unprecedented challenge for high-efficiency surveillance video coding technology. Compared with the existing coding standards that were basically developed for generic videos, surveillance video coding should be designed to make the best use of the special characteristics of surveillance videos (e.g., relative static background). To do so, this paper first conducts two analyses on how to improve the background and foreground prediction efficiencies in surveillance video coding. Following the analysis results, we propose a background-modeling-based adaptive prediction (BMAP) method. In this method, all blocks to be encoded are firstly classified into three categories. Then, according to the category of each block, two novel inter predictions are selectively utilized, namely, the background reference prediction (BRP) that uses the background modeled from the original input frames as the long-term reference and the background difference prediction (BDP) that predicts the current data in the background difference domain. For background blocks, the BRP can effectively improve the prediction efficiency using the higher quality background as the reference; whereas for foreground-background-hybrid blocks, the BDP can provide a better reference after subtracting its background pixels. Experimental results show that the BMAP can achieve at least twice the compression ratio on surveillance videos as AVC (MPEG-4 Advanced Video Coding) high profile, yet with a slightly additional encoding complexity. Moreover, for the foreground coding performance, which is crucial to the subjective quality of moving objects in surveillance videos, BMAP also obtains remarkable gains over several state-of-the-art methods.

  10. The semi-empirical low-level background statistics

    International Nuclear Information System (INIS)

    Tran Manh Toan; Nguyen Trieu Tu

    1992-01-01

    A semi-empirical low-level background statistics was proposed. The one can be applied to evaluated the sensitivity of low background systems, and to analyse the statistical error, the 'Rejection' and 'Accordance' criteria for processing of low-level experimental data. (author). 5 refs, 1 figs

  11. Towards an effective bilocal theory from QCD in a background

    International Nuclear Information System (INIS)

    Magpantay, J.A.

    1982-05-01

    Using the path integral, we show how we can get background gauge invariant bilocals (to be identified with mesons) from QCD in a nontrivial ground state. We discuss in this paper mainly the formal manipulations, especially how to deal with the zero modes. We also discuss the large N limit of QCD in a background. (author)

  12. Auditory intensity processing: Effect of MRI background noise.

    Science.gov (United States)

    Angenstein, Nicole; Stadler, Jörg; Brechmann, André

    2016-03-01

    Studies on active auditory intensity discrimination in humans showed equivocal results regarding the lateralization of processing. Whereas experiments with a moderate background found evidence for right lateralized processing of intensity, functional magnetic resonance imaging (fMRI) studies with background scanner noise suggest more left lateralized processing. With the present fMRI study, we compared the task dependent lateralization of intensity processing between a conventional continuous echo planar imaging (EPI) sequence with a loud background scanner noise and a fast low-angle shot (FLASH) sequence with a soft background scanner noise. To determine the lateralization of the processing, we employed the contralateral noise procedure. Linearly frequency modulated (FM) tones were presented monaurally with and without contralateral noise. During both the EPI and the FLASH measurement, the left auditory cortex was more strongly involved than the right auditory cortex while participants categorized the intensity of FM tones. This was shown by a strong effect of the additional contralateral noise on the activity in the left auditory cortex. This means a massive reduction in background scanner noise still leads to a significant left lateralized effect. This suggests that the reversed lateralization in fMRI studies with loud background noise in contrast to studies with softer background cannot be fully explained by the MRI background noise. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Listening to Students from Refugee Backgrounds: Lessons for Education Professionals

    Science.gov (United States)

    Mthethwa-Sommers, Shirley; Kisiara, Otieno

    2015-01-01

    This article is based on a study that examined how students from refugee backgrounds cope with victimization and bullying in three urban high schools in the United States. Qualitative methods of data collection and analysis were employed. Twelve high school students from refugee backgrounds participated in the study, which involved focus group…

  14. Iterative estimation of the background in noisy spectroscopic data

    International Nuclear Information System (INIS)

    Zhu, M.H.; Liu, L.G.; Cheng, Y.S.; Dong, T.K.; You, Z.; Xu, A.A.

    2009-01-01

    In this paper, we present an iterative filtering method to estimate the background of noisy spectroscopic data. The proposed method avoids the calculation of the average full width at half maximum (FWHM) of the whole spectrum and the peak regions, and it can estimate the background efficiently, especially for spectroscopic data with the Compton continuum.

  15. Narrative Career Counselling for People with Refugee Backgrounds

    Science.gov (United States)

    Abkhezr, Peyman; McMahon, Mary

    2017-01-01

    For people with refugee backgrounds, pursuing a meaningful career in their country of resettlement is important for their successful integration. However, for many, achieving this is a challenging process. Career counsellors may have a role to play in facilitating the transition and integration of people with refugee backgrounds, and narrative…

  16. The Influence Of Parental Background On Academic Performance Of ...

    African Journals Online (AJOL)

    It was hypothesized that there is no significant difference between the academic performance of students from high socio-economic status background and those from low SES backgrounds, also there is no significant difference between the academic performance of students form intact homes and the broken homes.

  17. Monitoring of external background radiation level in Asa dam ...

    African Journals Online (AJOL)

    An external background ionizing radiation study has been carried out within the Asa Dam Industrial Layout of Ilorin in Kwara State. The study was carried out in 5 stations within the industrial area using two Digilert Nuclear Radiation Monitors. The study has revealed that the external background ionizing radiation is ...

  18. Background radiation study of Offa industrial area of Kwara State ...

    African Journals Online (AJOL)

    A study of the external background radiation in Offa industrial area of Kwara State is hereby reported. An in-situ measurement using two Digilert radiation monitors at five different stations were carried out. A mean exposure rate of 0.0132mR/hr, which represents 20% elevation from the standard background radiation, was ...

  19. Background television in the homes of American children

    NARCIS (Netherlands)

    Lapierre, M.A.; Piotrowski, J.; Linebarger, D.L.

    2012-01-01

    Research has shown the negative consequences associated with children’s exposure to background television. Despite this evidence, researchers do not have reliable estimates of the prevalence of background television in American homes. This study sought to address this gap by providing the first

  20. Background television in the homes of US children.

    Science.gov (United States)

    Lapierre, Matthew A; Piotrowski, Jessica Taylor; Linebarger, Deborah L

    2012-11-01

    US parents were surveyed to determine the amount of background television that their children are exposed to as well as to isolate demographic factors associated with increased exposure to background television. After this, we ask how certain home media practices are linked to children's background television exposure. US parents/caregivers (N = 1454) with 1 child between the ages of 8 months and 8 years participated in this study. A nationally representative telephone survey was conducted. Parents were asked to report on their child's exposure to background television via a 24-hour time diary. Parents were also asked to report relevant home media behaviors related to their child: bedroom television ownership, number of televisions in the home, and how often a television was on in the home. The average US child was exposed to 232.2 minutes of background television on a typical day. With the use of multiple regression analysis, we found that younger children and African American children were exposed to more background television. Leaving the television on while no one is viewing and children's bedroom television ownership were associated with increased background television exposure. Although recent research has shown the negative consequences associated with background television, this study provides the first nationally representative estimates of that exposure. The amount of exposure for the average child is startling. This study offers practitioners potential pathways to reduce exposure.

  1. Background television in the homes of US children

    NARCIS (Netherlands)

    Lapierre, M.A.; Piotrowski, J.; Linebarger, D.L.

    2012-01-01

    OBJECTIVE: US parents were surveyed to determine the amount of background television that their children are exposed to as well as to isolate demographic factors associated with increased exposure to background television. After this, we ask how certain home media practices are linked to children’s

  2. Nonabelian gauge fields in the background of magnetic strings

    International Nuclear Information System (INIS)

    Wieczorek, E.

    1993-01-01

    Quantized nonabelian gauge fields are studied in the external classical background of a linear magnetic string. The determination of the gauge field propagator demands a specification of the string by suitable physical limiting procedures. The vacuum energy density is obtained after transforming the background problem into a Casimir problem. (orig.)

  3. Intellectual Assessment of Children from Culturally Diverse Backgrounds.

    Science.gov (United States)

    Armour-Thomas, Eleanor

    1992-01-01

    Examines assumptions and premises of standardized tests of mental ability and reviews extant theories and research on intellectual functioning of children from culturally different backgrounds. Discusses implications of these issues and perspectives for new directions for intellectual assessment for children from culturally different backgrounds.…

  4. Big bang nucleosynthesis and the cosmic neutrino background

    International Nuclear Information System (INIS)

    Cao Yun; Xing Zhizhong

    2013-01-01

    We present a brief overview of the neutrino decoupling and big bang nucleosynthesis in the early universe. The big bang relic neutrinos formed one of the backgrounds of the universe. A few possible ways to directly detect the cosmic neutrino background are briefly introduced, and particular attention is paid to the relic neutrino capture on b-decaying nuclei. (authors)

  5. Effect of a background electric field on the Hagedorn temperature

    International Nuclear Information System (INIS)

    Ferrer, E.J.; Incera, V. de la; Fradkin, E.S.

    1990-07-01

    We compute the one-loop free energy of the open neutral string gas in a constant electromagnetic background. Starting from this result we show that the Hagedorn temperature of this hot string gas depends on the background electric field. The larger the electric field, the lower the Hagedorn temperature is. (author). 13 refs

  6. Global symmetries of open strings in an electromagnetic background

    International Nuclear Information System (INIS)

    Ferrer, E.J.; de la Incera, V.

    1994-01-01

    The global symmetries of open bosonic strings in an electromagnetic background are investigated. The Poincare subalgebra and the mass of the open charged string are derived. These results are useful for computing the background electric field dependence of the one-loop free energy and Hagedorn temperature of a neutral string gas

  7. Advanced Background Subtraction Applied to Aeroacoustic Wind Tunnel Testing

    Science.gov (United States)

    Bahr, Christopher J.; Horne, William C.

    2015-01-01

    An advanced form of background subtraction is presented and applied to aeroacoustic wind tunnel data. A variant of this method has seen use in other fields such as climatology and medical imaging. The technique, based on an eigenvalue decomposition of the background noise cross-spectral matrix, is robust against situations where isolated background auto-spectral levels are measured to be higher than levels of combined source and background signals. It also provides an alternate estimate of the cross-spectrum, which previously might have poor definition for low signal-to-noise ratio measurements. Simulated results indicate similar performance to conventional background subtraction when the subtracted spectra are weaker than the true contaminating background levels. Superior performance is observed when the subtracted spectra are stronger than the true contaminating background levels. Experimental results show limited success in recovering signal behavior for data where conventional background subtraction fails. They also demonstrate the new subtraction technique's ability to maintain a proper coherence relationship in the modified cross-spectral matrix. Beam-forming and de-convolution results indicate the method can successfully separate sources. Results also show a reduced need for the use of diagonal removal in phased array processing, at least for the limited data sets considered.

  8. Simulation of Beam-Beam Background at CLIC

    CERN Document Server

    Sailer, Andre

    2010-01-01

    The dense beams used at CLIC to achieve a high luminosity will cause a large amount of background particles through beam-beam interactions. Generator level studies with GuineaPig and full detector simulation studies with an ILD based CLIC detector have been performed to evaluate the amount of beam-beam background hitting the vertex detector.

  9. Optimization of the Regularization in Background and Foreground Modeling

    Directory of Open Access Journals (Sweden)

    Si-Qi Wang

    2014-01-01

    Full Text Available Background and foreground modeling is a typical method in the application of computer vision. The current general “low-rank + sparse” model decomposes the frames from the video sequences into low-rank background and sparse foreground. But the sparse assumption in such a model may not conform with the reality, and the model cannot directly reflect the correlation between the background and foreground either. Thus, we present a novel model to solve this problem by decomposing the arranged data matrix D into low-rank background L and moving foreground M. Here, we only need to give the priori assumption of the background to be low-rank and let the foreground be separated from the background as much as possible. Based on this division, we use a pair of dual norms, nuclear norm and spectral norm, to regularize the foreground and background, respectively. Furthermore, we use a reweighted function instead of the normal norm so as to get a better and faster approximation model. Detailed explanation based on linear algebra about our two models will be presented in this paper. By the observation of the experimental results, we can see that our model can get better background modeling, and even simplified versions of our algorithms perform better than mainstream techniques IALM and GoDec.

  10. Incremental principal component pursuit for video background modeling

    Science.gov (United States)

    Rodriquez-Valderrama, Paul A.; Wohlberg, Brendt

    2017-03-14

    An incremental Principal Component Pursuit (PCP) algorithm for video background modeling that is able to process one frame at a time while adapting to changes in background, with a computational complexity that allows for real-time processing, having a low memory footprint and is robust to translational and rotational jitter.

  11. Ambitwistor pure spinor string in a type II supergravity background

    Energy Technology Data Exchange (ETDEWEB)

    Chandia, Osvaldo [Departamento de Ciencias, Facultad de Artes Liberales, Universidad Adolfo Ibáñez,Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez,Diagonal Las Torres 2640, Peñalolén, Santiago (Chile); Vallilo, Brenno Carlini [Departamento de Ciencias Físicas, Facultad de Ciencias Exactas, Universidad Andres Bello,República 220, Santiago (Chile)

    2015-06-30

    We construct the ambitwistor pure spinor string in a general type II supergravity background in the semi-classical regime. Almost all supergravity constraints are obtained from nilpotency of the BRST charge and further consistency conditions from additional world-sheet the case of AdS{sub 5}×S{sup 5} background.

  12. Background Music in Educational Games: Motivational Appeal and Cognitive Impact

    Science.gov (United States)

    Linek, Stephanie B.; Marte, Birgit; Albert, Dietrich

    2011-01-01

    Most game-designers likely stick to the assumption that background music is a design feature for fostering fun and game play. From a psychological point of view, these (intuitive) aspects act upon the intrinsic motivation and the flow experience of players. However, from a pure cognitive perspective on instructional design, background music could…

  13. General Music Teachers' Backgrounds and Multicultural Repertoire Selection

    Science.gov (United States)

    Lee, Soojin

    2018-01-01

    The purpose of this qualitative study was to examine how teachers' backgrounds could contribute to their decisions to include music from diverse cultures. Analysis of interviews with three general music teachers indicated that their music training and experiences, ethnic backgrounds, and years of teaching experience may have influenced their…

  14. Radon-related Backgrounds in the LUX Dark Matter Search

    Science.gov (United States)

    Bradley, A.; Akerib, D. S.; Araújo, H. M.; Bai, X.; Bailey, A. J.; Balajthy, J.; Bernard, E.; Bernstein, A.; Byram, D.; Cahn, S. B.; Carmona-Benitez, M. C.; Chan, C.; Chapman, J. J.; Chiller, A. A.; Chiller, C.; Coffey, T.; Currie, A.; de Viveiros, L.; Dobi, A.; Dobson, J.; Druszkiewicz, E.; Edwards, B.; Faham, C. H.; Fiorucci, S.; Flores, C.; Gaitskell, R. J.; Gehman, V. M.; Ghag, C.; Gibson, K. R.; Gilchriese, M. G. D.; Hall, C.; Hertel, S. A.; Horn, M.; Huang, D. Q.; Ihm, M.; Jacobsen, R. G.; Kazkaz, K.; Knoche, R.; Larsen, N. A.; Lee, C.; Lindote, A.; Lopes, M. I.; Malling, D. C.; Mannino, R.; McKinsey, D. N.; Mei, D.-M.; Mock, J.; Moongweluwan, M.; Morad, J.; Murphy, A. St. J.; Nehrkorn, C.; Nelson, H.; Neves, F.; Ott, R. A.; Pangilinan, M.; Parker, P. D.; Pease, E. K.; Pech, K.; Phelps, P.; Reichhart, L.; Shutt, T.; Silva, C.; Solovov, V. N.; Sorensen, P.; O'Sullivan, K.; Sumner, T. J.; Szydagis, M.; Taylor, D.; Tennyson, B.; Tiedt, D. R.; Tripathi, M.; Uvarov, S.; Verbus, J. R.; Walsh, N.; Webb, R.; White, J. T.; Witherell, M. S.; Wolfs, F. L. H.; Woods, M.; Zhang, C.

    The LUX detector is currently in operation at the Davis Campus at the 4850' level of the Sanford Underground Research Facility (SURF) in Lead, SD to directly search for WIMP dark matter. Knowing the type and rate of backgrounds is critical in a rare, low energy event search, and LUX was designed, constructed, and deployed to mitigate backgrounds, both internal and external. An important internal background are decays of radon and its daughters. These consist of alpha decays, which are easily tagged and are a tracer of certain backgrounds, and beta decays, some of which are not as readily tagged and present a background for the WIMP search. We report on studies of alpha decay and discuss implications for the WIMP search.

  15. Study of Background Rejection Systems for the IXO Mission.

    Science.gov (United States)

    Laurent, Philippe; Limousin, O.; Tatischeff, V.

    2009-01-01

    The scientific performances of the IXO mission will necessitate a very low detector background level. This will imply thorough background simulations, and efficient background rejection systems. It necessitates also a very good knowledge of the detectors to be shielded. In APC, Paris, and CEA, Saclay, we got experience on these activities by conceiving and optimising in parallel the high energy detector and the active and passive background rejection system of the Simbol-X mission. Considering that this work may be naturally extended to other X-ray missions, we have initiated with CNES a R&D project on the study of background rejection systems mainly in view the IXO project. We will detail this activity in the poster.

  16. Scientific results from the cosmic background explorer (COBE)

    International Nuclear Information System (INIS)

    Bennett, C.L.; Boggess, N.W.; Cheng, E.S.; Hauser, M.G.; Kelsall, T.; Mather, J.C.; Moseley, S.H. Jr.; Shafer, R.A.; Silverberg, R.F.; Murdock, T.L.; Smoot, G.F.; Weiss, R.; Wright, E.L.

    1993-01-01

    The National Aeronautics and Space Administration (NASA) has flown the COBE satellite to observe the Big Bang and the subsequent formation of galaxies and large-scale structure. Data from the Far-Infrared Absolute Spectrophotometer (FIRAS) show that the spectrum of the cosmic microwave background is that of a black body of temperature T = 2.73 ± 0.06 K, with no deviation from a black-body spectrum greater than 0.25% of the peak brightness. The data from the Differential Microwave Radiometers (DMR) show statistically significant cosmic microwave background anisotropy, consistent with a scale-invariant primordial density fluctuation spectrum. Measurements from the Diffuse Infrared Background Experiment (DIRBE) provide new conservation upper limits to the cosmic infrared background. Extensive modeling of solar system and galactic infrared foregrounds is required for further improvement in the cosmic infrared background limits. 104 refs., 1 tab

  17. Neutron- and muon-induced background in underground physics experiments

    International Nuclear Information System (INIS)

    Kudryavtsev, V.A.; Tomasello, V.; Pandola, L.

    2008-01-01

    Background induced by neutrons in deep underground laboratories is a critical issue for all experiments looking for rare events, such as dark matter interactions or neutrinoless ββ decay. Neutrons can be produced either by natural radioactivity, via spontaneous fission or (α, n) reactions, or by interactions initiated by high-energy cosmic rays. In all underground experiments, Monte Carlo simulations of neutron background play a crucial role for the evaluation of the total background rate and for the optimization of rejection strategies. The Monte Carlo methods that are commonly employed to evaluate neutron-induced background and to optimize the experimental setup, are reviewed and discussed. Focus is given to the issue of reliability of Monte Carlo background estimates. (orig.)

  18. Neutron- and muon-induced background in underground physics experiments

    Energy Technology Data Exchange (ETDEWEB)

    Kudryavtsev, V.A.; Tomasello, V. [University of Sheffield, Department of Physics and Astronomy, Sheffield (United Kingdom); Pandola, L. [Laboratori Nazionali del Gran Sasso, INFN, Assergi (Italy)

    2008-05-15

    Background induced by neutrons in deep underground laboratories is a critical issue for all experiments looking for rare events, such as dark matter interactions or neutrinoless {beta}{beta} decay. Neutrons can be produced either by natural radioactivity, via spontaneous fission or ({alpha}, n) reactions, or by interactions initiated by high-energy cosmic rays. In all underground experiments, Monte Carlo simulations of neutron background play a crucial role for the evaluation of the total background rate and for the optimization of rejection strategies. The Monte Carlo methods that are commonly employed to evaluate neutron-induced background and to optimize the experimental setup, are reviewed and discussed. Focus is given to the issue of reliability of Monte Carlo background estimates. (orig.)

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

    Science.gov (United States)

    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.

  20. Association of Radon Background and Total Background Ionizing Radiation with Alzheimer's Disease Deaths in U.S. States.

    Science.gov (United States)

    Lehrer, Steven; Rheinstein, Peter H; Rosenzweig, Kenneth E

    2017-01-01

    Exposure of the brain to ionizing radiation might promote the development of Alzheimer's disease (AD). Analysis of AD death rates versus radon background radiation and total background radiation in U.S. states. Total background, radon background, cosmic and terrestrial background radiation measurements are from Assessment of Variations in Radiation Exposure in the United States and Report No. 160 - Ionizing Radiation Exposure of the Population of the United States. 2013 AD death rates by U.S. state are from the Alzheimer's Association. Radon background ionizing radiation was significantly correlated with AD death rate in 50 states and the District of Columbia (r = 0.467, p = 0.001). Total background ionizing radiation was also significantly correlated with AD death rate in 50 states and the District of Columbia (r = 0.452, p = 0.001). Multivariate linear regression weighted by state population demonstrated that AD death rate was significantly correlated with radon background (β= 0.169, p ionizing radiation is a risk factor for AD. Intranasal inhalation of radon gas could subject the rhinencephalon and hippocampus to damaging radiation that initiates AD. The damage would accumulate over time, causing age to be a powerful risk factor.

  1. Optimal Background Attenuation for Fielded Radiation Detection Systems

    International Nuclear Information System (INIS)

    Robinson, Sean M.; Kaye, William R.; Schweppe, John E.; Siciliano, Edward R.

    2006-01-01

    Radiation detectors are often placed in positions difficult to shield from the effects of terrestrial background. This is particularly true in the case of Radiation Portal Monitor (RPM) systems, as their wide viewing angle and outdoor installations make them susceptible to terrestrial background from the surrounding area. A low background is desired in most cases, especially when the background noise is of comparable strength to the signal of interest. The problem of shielding a generalized RPM from terrestrial background is considered. Various detector and shielding scenarios are modeled with the Monte-Carlo N Particle (MCNP) computer code. Amounts of nominal-density shielding needed to attenuate the terrestrial background to varying degrees are given, along with optimal shielding geometry to be used in areas where natural shielding is limited, and where radiation detection must occur in the presence of natural background. Common shielding solutions such as steel plating are evaluated based on the signal to noise ratio and the benefits are weighed against the incremental cost.

  2. Interdependent processing and encoding of speech and concurrent background noise.

    Science.gov (United States)

    Cooper, Angela; Brouwer, Susanne; Bradlow, Ann R

    2015-05-01

    Speech processing can often take place in adverse listening conditions that involve the mixing of speech and background noise. In this study, we investigated processing dependencies between background noise and indexical speech features, using a speeded classification paradigm (Garner, 1974; Exp. 1), and whether background noise is encoded and represented in memory for spoken words in a continuous recognition memory paradigm (Exp. 2). Whether or not the noise spectrally overlapped with the speech signal was also manipulated. The results of Experiment 1 indicated that background noise and indexical features of speech (gender, talker identity) cannot be completely segregated during processing, even when the two auditory streams are spectrally nonoverlapping. Perceptual interference was asymmetric, whereby irrelevant indexical feature variation in the speech signal slowed noise classification to a greater extent than irrelevant noise variation slowed speech classification. This asymmetry may stem from the fact that speech features have greater functional relevance to listeners, and are thus more difficult to selectively ignore than background noise. Experiment 2 revealed that a recognition cost for words embedded in different types of background noise on the first and second occurrences only emerged when the noise and the speech signal were spectrally overlapping. Together, these data suggest integral processing of speech and background noise, modulated by the level of processing and the spectral separation of the speech and noise.

  3. Origin of the cosmic x-ray background

    International Nuclear Information System (INIS)

    Margon, B.

    1983-01-01

    Since 1962, it has been known that every part of the sky emits a uniform glow of x-rays. After two decades of intense study the origin of this diffuse x-ray background is still a subject of controversy. The near perfect isotropy of the x-ray background is clearly a vital clue to its origin. A second clue to the origin of the x-ray background arises from the fact that it is x-radiation tha is generated, rather than some longer wavelength radiation. Two hypotheses of the origin of this x-ray background are discussed. One hypothesis is that the x-ray background can be attributed to bremsstrahlung from a hot intergalactic medium. The second hypothesis is that the x-ray background originates from a large number of quasars. Because there is no estimate independent of the intensity of the x-ray background of how much hot intergalactic medium exists (if any), there is a real possibility that both sources contribute to the observed x-rays. (SC)

  4. Reducing DRIFT backgrounds with a submicron aluminized-mylar cathode

    Science.gov (United States)

    Battat, J. B. R.; Daw, E.; Dorofeev, A.; Ezeribe, A. C.; Fox, J. R.; Gauvreau, J.-L.; Gold, M.; Harmon, L.; Harton, J.; Lafler, R.; Landers, J.; Lauer, R. J.; Lee, E. R.; Loomba, D.; Lumnah, A.; Matthews, J.; Miller, E. H.; Mouton, F.; Murphy, A. St. J.; Paling, S. M.; Phan, N.; Sadler, S. W.; Scarff, A.; Schuckman, F. G.; Snowden-Ifft, D.; Spooner, N. J. C.; Walker, D.

    2015-09-01

    Background events in the DRIFT-IId dark matter detector, mimicking potential WIMP signals, are predominantly caused by alpha decays on the central cathode in which the alpha particle is completely or partially absorbed by the cathode material. We installed a 0.9 μm thick aluminized-mylar cathode as a way to reduce the probability of producing these backgrounds. We study three generations of cathode (wire, thin-film, and radiologically clean thin-film) with a focus on the ratio of background events to alpha decays. Two independent methods of measuring the absolute alpha decay rate are used to ensure an accurate result, and agree to within 10%. Using alpha range spectroscopy, we measure the radiologically cleanest cathode version to have a contamination of 3.3±0.1 ppt 234U and 73±2 ppb 238U. This cathode reduces the probability of producing an RPR from an alpha decay by a factor of 70±20 compared to the original stainless steel wire cathode. First results are presented from a texturized version of the cathode, intended to be even more transparent to alpha particles. These efforts, along with other background reduction measures, have resulted in a drop in the observed background rate from 500/day to 1/day. With the recent implementation of full-volume fiducialization, these remaining background events are identified, allowing for background-free operation.

  5. Effects of placement point of background music on shopping website.

    Science.gov (United States)

    Lai, Chien-Jung; Chiang, Chia-Chi

    2012-01-01

    Consumer on-line behaviors are more important than ever due to highly growth of on-line shopping. The purposes of this study were to design placement methods of background music for shopping website and examine the effect on browsers' emotional and cognitive response. Three placement points of background music during the browsing, i.e. 2 min., 4 min., and 6 min. from the start of browsing were considered for entry points. Both browsing without music (no music) and browsing with constant music volume (full music) were treated as control groups. Participants' emotional state, approach-avoidance behavior intention, and action to adjust music volume were collected. Results showed that participants had a higher level of pleasure, arousal and approach behavior intention for the three placement points than for no music and full music. Most of the participants for full music (5/6) adjusted the background music. Only 16.7% (3/18) participants for other levels turn off the background music. The results indicate that playing background music after the start of browsing is benefit for on-line shopping atmosphere. It is inappropriate to place background music at the start of browsing shopping website. The marketer must manipulated placement methods of background music for a web store carefully.

  6. EPR dosimetry of radiation background in the Urals region

    Energy Technology Data Exchange (ETDEWEB)

    Shishkina, E.A.; Degteva, M.O.; Shved, V.A. [Urals Research Center for Radiation Medicine, 48-A Vorovsky, Chelyabinsk 454076 (Russian Federation); Fattibene, P.; Onori, S. [Istituto Superiore di Sanita and Istituto Nazionale di Fisica Nucleare (Italy); Wieser, A. [GSF, Forschungszentrum fuer Umwelt und Gesundheit, Ingolstaedter Landstr (Germany); Ivanov, D.V.; Bayankin, S.N. [Institute of Metal Physics, Russian Academy of Sciences (Russian Federation); Knyazev, V.A.; Vasilenko, E.I.; Gorelov, M. [ZAO, Closed Corporation ' Company GEOSPETSECOLOGIA' (Russian Federation)

    2006-07-01

    Method of Electron Paramagnetic Resonance is extensively applied to individual retrospective dosimetry. The background dose is unavoidable component of cumulative absorbed dose in the tooth enamel accumulated during the lifetime of donor. Estimation of incidental radiation dose using tooth enamel needs in extraction of background dose. Moreover, the variation of background doses in the population is a limited factor for reliable detection of additional irradiation especially for low dose level. Therefore the accurate knowledge of the natural background radiation dose is a critical element of EPR studies of exposed populations. In the Urals region the method applies for such two large cohorts as the workers of Mayak (Ozersk citizens) and Techa River riverside inhabitants (rural population). Current study aimed to investigate the Urals radiation background detected by EPR spectrometry. For this aim two group of unexposed Urals residents were separated, viz: citizens of Ozersk and rural inhabitants of Chelyabinsk region. Comparison of two investigated territories has demonstrated that from the point of view of radiation background it is impossible to assume the Urals population as uniform. The reliable difference between the urban and rural residents has been found. The average background doses of Ozersk donors is in average 50 mGy higher than those detected for rural residents. The individual variability of background doses for Osersk has been higher than in the rural results. The difference in background dose levels between two population results in different limits of accidental dose detection and individualization. The doses for 'Mayak' workers (Ozyorsk citizens) can be classed as anthropogenic if the EPR measurements exceed 120 mGy for teeth younger than 40 years, and 240 mGy for teeth older than 70 years. The anthropogenic doses for Techa River residents (rural population) would be higher than 95 mGy for teeth younger than 50 years and 270 mGy for

  7. Background approximation in automatic qualitative X-ray-fluorescent analysis

    International Nuclear Information System (INIS)

    Jordanov, J.; Tsanov, T.; Stefanov, R.; Jordanov, N.; Paunov, M.

    1982-01-01

    An empirical method of finding the dependence of the background intensity (Isub(bg) on the wavelength is proposed, based on the approximation of the experimentally found values for the background in the course of an automatic qualitative X-ray fluorescent analysis with pre-set curve. It is assumed that the dependence I(lambda) will be well approximated by a curve of the type Isub(bg)=(lambda-lambda sub(o)sup(fsub(1)(lambda))exp[fsub(2)(lambda)] where fsub(1) (lambda) and f 2 (lambda) are linear functions with respect to the sought parameters. This assumption was checked out on a ''pure'' starch background, in which it is not known beforehand which points belong to the background. It was assumed that the dependence I(lambda) can be found from all minima in the spectrum. Three types of minima has been distinguished: 1. the lowest point between two well-solved X-ray lines; 2. a minimum obtained as a result of statistical fluctuations of the measured signal; 3. the lowest point between two overlapped lines. The minima strongly deviating from the background are removed from the obtained set. The sum-total of the remaining minima serves as a base for the approximation of the dependence I(lambda). The unknown parameters are determined by means of the LSM. The approximated curve obtained by this method is closer to the real background than the background determined by the method described by Kigaki Denki, as the effect of all recorded minima is taken into account. As an example the PbTe spectrum recorded with crystal LiF 220 is shown graphically. The curve well describes the background of the spectrum even in the regions in which there are no minima belonging to the background. (authors)

  8. EPR dosimetry of radiation background in the Urals region

    International Nuclear Information System (INIS)

    Shishkina, E.A.; Degteva, M.O.; Shved, V.A.; Fattibene, P.; Onori, S.; Wieser, A.; Ivanov, D.V.; Bayankin, S.N.; Knyazev, V.A.; Vasilenko, E.I.; Gorelov, M.

    2006-01-01

    Method of Electron Paramagnetic Resonance is extensively applied to individual retrospective dosimetry. The background dose is unavoidable component of cumulative absorbed dose in the tooth enamel accumulated during the lifetime of donor. Estimation of incidental radiation dose using tooth enamel needs in extraction of background dose. Moreover, the variation of background doses in the population is a limited factor for reliable detection of additional irradiation especially for low dose level. Therefore the accurate knowledge of the natural background radiation dose is a critical element of EPR studies of exposed populations. In the Urals region the method applies for such two large cohorts as the workers of Mayak (Ozersk citizens) and Techa River riverside inhabitants (rural population). Current study aimed to investigate the Urals radiation background detected by EPR spectrometry. For this aim two group of unexposed Urals residents were separated, viz: citizens of Ozersk and rural inhabitants of Chelyabinsk region. Comparison of two investigated territories has demonstrated that from the point of view of radiation background it is impossible to assume the Urals population as uniform. The reliable difference between the urban and rural residents has been found. The average background doses of Ozersk donors is in average 50 mGy higher than those detected for rural residents. The individual variability of background doses for Osersk has been higher than in the rural results. The difference in background dose levels between two population results in different limits of accidental dose detection and individualization. The doses for 'Mayak' workers (Ozyorsk citizens) can be classed as anthropogenic if the EPR measurements exceed 120 mGy for teeth younger than 40 years, and 240 mGy for teeth older than 70 years. The anthropogenic doses for Techa River residents (rural population) would be higher than 95 mGy for teeth younger than 50 years and 270 mGy for teeth older

  9. SNAP sky background at the north ecliptic pole

    International Nuclear Information System (INIS)

    Aldering, Greg

    2002-01-01

    I summarize the extant direct and indirect data on the sky background SNAP will see at the North Ecliptic Pole over the wavelength range 0.4 < λ < 1.7 (micro)m. At the spatial resolution of SNAP the sky background due to stars and galaxies is resolved, so the only source considered is zodiacal light. Several models are explored to provide interpolation in wavelength between the broadband data from HST and COBE observations. I believe the input data are now established well enough that the accuracy of the sky background presented here is sufficient for SNAP simulations, and that it will stand up to scrutiny by reviewers

  10. Nonperturbative quantum electrodynamics in a photon-condensate background field

    International Nuclear Information System (INIS)

    Kikuchi, Y.; Ng, Y.J.

    1988-01-01

    Analyses of the Schwinger-Dyson (SD) equation for the fermion self-energy have revealed the existence of a QED ultraviolet nonperturbative fixed point which separates a strong-coupling regime from a weak-coupling regime. Here we study the SD equation in the presence of a weak constant photon-condensate background field. This background field does not seem to affect the fixed point. Better approximations or some more realistic background fields may change the result. The investigation is partly motivated by recent heavy-ion experiments

  11. DOES FAMILY BACKGROUND MATTER FOR LEARNING IN EAST AFRICA?

    DEFF Research Database (Denmark)

    Jones, Edward Samuel; Schipper, Youdi

    2015-01-01

    The extent to which differences in family background characteristics explain differences in learning outcomes between children captures the extent of equality in educational opportunities. This study uses large-scale data on literacy and numeracy outcomes for children of school age across East....... Even so, family background does not fully explain why children of school starting age display large differences in learning between countries....... Africa (Kenya, Tanzania and Uganda) to investigate the contribution of family background to learning differences. We find that learning differences between children from less-advantaged households and those from more-advantaged households equals around one year or more of effective learning on average...

  12. Reference analysis of the signal + background model in counting experiments

    Science.gov (United States)

    Casadei, D.

    2012-01-01

    The model representing two independent Poisson processes, labelled as ``signal'' and ``background'' and both contributing additively to the total number of counted events, is considered from a Bayesian point of view. This is a widely used model for the searches of rare or exotic events in presence of a background source, as for example in the searches performed by high-energy physics experiments. In the assumption of prior knowledge about the background yield, a reference prior is obtained for the signal alone and its properties are studied. Finally, the properties of the full solution, the marginal reference posterior, are illustrated with few examples.

  13. Anomalous cosmic-microwave-background polarization and gravitational chirality.

    Science.gov (United States)

    Contaldi, Carlo R; Magueijo, João; Smolin, Lee

    2008-10-03

    We consider the possibility that gravity breaks parity, with left and right-handed gravitons coupling to matter with a different Newton's constant and show that this would affect their zero-point vacuum fluctuations during inflation. Should there be a cosmic background of gravity waves, the effect would translate into anomalous cosmic microwave background polarization. Nonvanishing temperature-magnetic (TB) mode [and electric-magnetic mode] components emerge, revealing interesting experimental targets. Indeed, if reasonable chirality is present a TB measurement would provide the easiest way to detect a gravitational wave background. We speculate on the theoretical implications of such an observation.

  14. Origin of the diffuse γ-ray background

    International Nuclear Information System (INIS)

    Strong, A.W.; Wolfendale, A.W.; Worrall, D.M.

    1976-01-01

    An attempt is made to assess the contributions to the diffuse γ-ray background from normal galaxies, radio galaxies and Seyfert galaxies. Normal galaxies produce about 4 per cent of the background above 100 MeV. Radio galaxies can produce most and perhaps all of the background in the 1 to 10 MeV range provided their evolution as γ-ray sources is similar to that for their radio properties. Seyfert galaxies will also be important if inverse Compton models are applicable to them, particularly at energies above about 100 MeV. (author)

  15. Muon-induced backgrounds in the CUORICINO experiment

    Energy Technology Data Exchange (ETDEWEB)

    Andreotti, E; Arnaboldi, C; Avignone, F T; Balata, M; Bandac, I; Barucci, M; Beeman, J W; Bellini, F; Bloxham, T; Brofferio, C; Bryant, A; Bucci, C; Canonica, L; Capelli, S; Carbone, L; Carrettoni, M; Clemenza, M; Cremonesi, O; Creswick, R J; Domizio, S D; Dolinski, M J; Ejzak, L; Faccini, R; Farach, H A; Ferri, E; Ferroni, F; Firoini, E; Foggetta, L; Giachero, A; Gironi, L; Giuliani, A; Gorla, P; Guardincerri, E; Gutierrez, T D; Haller, E E; Kadel, R; Kazkaz, K; Kraft, S; Kogler, L; Kolomensky, Y G; Maiano, C; Maruyama, R H; Martinez, C; Martinez, M; Mizouni, L; Morganti, S; Nisi, S; Nones, C; Norman, E B; Nucciotti, A; Orio, F; Pallavicini, M; Palmieri, V; Pattavina, L; Pavan, M; Pedretti, M; Pessina, G; Pirro, S; Previtali, E; Risegari, L; Rosenfeld, C; Rusconi, C; Salvioni, C; Sangiorgio, S; Schaeffer, D; Scielzo, N D; Sisti, M; Smith, A R; Tomei, C; Ventura, G; Vignati, M

    2009-11-16

    To better understand the contribution of cosmic ray muons to the CUORICINO background, ten plastic scintillator detectors were installed at the CUORICINO site and operated during 3 months of the CUORICINO experiment. From these measurements, an upper limit of 0.0021 counts/keV {center_dot} kg {center_dot} yr (95% C.L.) was obtained on the cosmic ray induced background in the neutrinoless double beta decay region of interest. The measurements were compared to Geant4 simulations, which are similar to those that will be used to estimate the backgrounds in CUORE.

  16. The Interaction of Local Context and Cultural Background

    DEFF Research Database (Denmark)

    Nielsen, Rikke Skovgaard; Holmqvist, Emma; Dhalman, Hanna

    2015-01-01

    Immigrants' housing position is often explained by (lack of) resources or differences in cultural backgrounds. Recent studies have included the importance of local context. The aim of this paper is to examine Somalis' perceptions of their possibilities in four Nordic capitals' housing markets...... and sometimes conflict with each other, but that the negotiation between cultural background and local context was individual. The conclusion is that local context and cultural background are important factors for understanding differences between Somalis on different housing markets, thus emphasising...

  17. The Importance of Background Culture Knowledge in Reading

    Institute of Scientific and Technical Information of China (English)

    王蓁

    2012-01-01

    As achieving cross-culture communication is the final aim of learning English,it turns out to be inefficient to attach more importance on the ability of listening,speaking,reading,writing and knowledge system.Background culture knowledge is supposed to be an important way to reach the aim of language teaching,and help readers understand articles.Considering the effects of background culture knowledge and its importance,this article will do a research on it and try to help both readers and teachers aware of the importance of background culture knowledge and take note of it.

  18. Influence of radiation damage on internal friction background

    International Nuclear Information System (INIS)

    Burbelo, R.M.; Grinik, Eh.U.; Paliokha, M.I.; Orlinskij, A.B.

    1984-01-01

    Influence of radiation damage on internal friction background in samples of polycrystalline nickel and iron irradiated by a fast neutron flux approximately 10 14 neutr/(cm 2 xs) at 350 deg C has been studied using the low-frequency unit of the reverse torsion pendulum type. It has been established experimentally that a high-temperature background of internal friction of iron and nickel samples decreases as accumulating radiation defects occurring under neutron irradiation. Assumptions on a possible mechanism of the effect have been proposed. Simple expression for the background magnitude evaluation has been suggested

  19. Investigation of reduction in background counts of clover detector

    International Nuclear Information System (INIS)

    Kshetri, Ritesh

    2015-01-01

    The peak-to-total ratio can be improved by increasing the full energy peak (FEP) counts and/or by decreasing the background counts. It is notable that FEP counts will be effected by mode of operation, while background counts will be effected by both modes of operation and suppression cases. It would be interesting to know if the reduction in background is caused more by active suppression or by add back process. We introduce a simple formalism to investigate the reduction of background counts for different cases-single crystal or add back mode with active or passive suppression. A more sophisticated formalism for modeling a general composite detector had been presented in a series of six recent papers by the author

  20. Development of background reduced Fresnel phase zone plate

    International Nuclear Information System (INIS)

    Tamari, Yohei; Azechi, Hiroshi

    2004-01-01

    In study of hot and dense plasma, a high spatial resolution (a few microns) x-ray imaging is very important to observe these plasmas. The Fresnel phase zone plate (FPZP) consists of alternately material and transparent circular annuli placed concentrically, which image x rays using diffraction x rays from all annuli. FPZP have imaged 4.7-4.77 keV x rays with 2.2 μm spatial resolution. However FPZP has a problem that background level is comparable to signal level. In subtraction of background, the error of 10% is caused. For the accurate background subtraction, we designed new FPZP, which consist of three β layers of a transparent zone and two material zones. The new design FPZP parameters (thickness of material zones, each zone width) have been optimized, and in that optimum design signal-to-background ratio is 4 times better than conventional two layers FPZP

  1. Multivariate Identification of Background Contributions for the H ! tt

    CERN Document Server

    Andrejkovic, Janik Walter

    2016-01-01

    Within the H ! tt analysis it is very important to understand the background contamination in the signal region coming from events where a jet is misidentified as a hadronic tau (fake events). Currently, the fake rate method is used to estimate the number and distributions of fake events in the signal region. This method relies on the correct identification of different background types. The study presented in this report focuses on the use of boosted decision trees in order to identify different background types. It is shown how the addition of more input variables, leading to a multi-dimensional multi-classification task, improves the overall identification accuracy of the different background types.

  2. Infection as a Background to Safety: Source Material for Teaching.

    Science.gov (United States)

    Wyatt, H. V.

    1986-01-01

    Offers selections from papers which illustrate accidents, epidemics, and bad practices which could be used as background material for lessons on laboratory safety. Advocates the need for instruction on pathogenicity and infectivity. (ML)

  3. Precision Foreground Removal in Cosmic Microwave Background Polarization Maps

    Data.gov (United States)

    National Aeronautics and Space Administration — The most promising method for detecting primordial gravitational waves lies in the B-mode polarization of the cosmic microwave background, or CMB. A measurement of...

  4. Measurement of Background Gamma Radiation Levels at Two ...

    African Journals Online (AJOL)

    MICHAEL

    ABSTRACT: An in-situ measurement of the background radiation level was carried out at the vicinity of three ... Soil contains small quantities of radioactive elements along with their progeny. .... assessment for soil samples from Kestanbol.

  5. Study of the GERDA Phase II background spectrum

    Science.gov (United States)

    Agostini, M.; Allardt, M.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Baudis, L.; Bauer, C.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Benato, G.; Bettini, A.; Bezrukov, L.; Bode, T.; Borowicz, D.; Brudanin, V.; Brugnera, R.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; D'Andrea, V.; Demidova, E. V.; Di Marco, N.; Domula, A.; Doroshkevich, E.; Egorov, V.; Falkenstein, R.; Frodyma, N.; Gangapshev, A.; Garfagnini, A.; Gooch, C.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Hakenmüller, J.; Hegai, A.; Heisel, M.; Hemmer, S.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Janicskó Csáthy, J.; Jochum, J.; Junker, M.; Kazalov, V.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Kish, A.; Klimenko, A.; Kneißl, R.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V. V.; Laubenstein, M.; Lazzaro, A.; Lebedev, V. I.; Lehnert, B.; Liao, H. Y.; Lindner, M.; Lippi, I.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Macolino, C.; Majorovits, B.; Maneschg, W.; Medinaceli, E.; Miloradovic, M.; Mingazheva, R.; Misiaszek, M.; Moseev, P.; Nemchenok, I.; Palioselitis, D.; Panas, K.; Pandola, L.; Pelczar, K.; Pullia, A.; Riboldi, S.; Rumyantseva, N.; Sada, C.; Salamida, F.; Salathe, M.; Schmitt, C.; Schneider, B.; Schönert, S.; Schreiner, J.; Schulz, O.; Schütz, A.-K.; Schwingenheuer, B.; Selivanenko, O.; Shevzik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Vanhoefer, L.; Vasenko, A. A.; Veresnikova, A.; von Sturm, K.; Wagner, V.; Wegmann, A.; Wester, T.; Wiesinger, C.; Wojcik, M.; Yanovich, E.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zuber, K.; Zuzel, G.

    2017-09-01

    The Gerda experiment, located at the Laboratori Nazionali del Gran Sasso (LNGS) of INFN in Italy, searches for the neutrinoless double beta (0νββ) decay of 76Ge. Gerda Phase II is aiming to reach a sensitivity for the 0νββ half life of 1026 yr in ˜ 3 years of physics data taking with 100 kg·yr of exposure and a background index of ˜ 10-3 cts/(keV·kg·yr). After 6 months of acquisition a first data release with 10.8 kg·yr of exposure is performed, showing that the design background is achieved. In this work a study of the Phase II background spectrum, the main spectral structures and the background sources will be presented and discussed.

  6. Background rejection in NEXT using deep neural networks

    CERN Document Server

    Renner, J.

    2017-01-01

    We investigate the potential of using deep learning techniques to reject background events in searches for neutrinoless double beta decay with high pressure xenon time projection chambers capable of detailed track reconstruction. The differences in the topological signatures of background and signal events can be learned by deep neural networks via training over many thousands of events. These networks can then be used to classify further events as signal or background, providing an additional background rejection factor at an acceptable loss of efficiency. The networks trained in this study performed better than previous methods developed based on the use of the same topological signatures by a factor of 1.2 to 1.6, and there is potential for further improvement.

  7. Noncommutative black-body radiation: Implications on cosmic microwave background

    International Nuclear Information System (INIS)

    Fatollahi, A.H.; Hajirahimi, M.

    2006-01-01

    Including loop corrections, black-body radiation in noncommutative space is anisotropic. A direct implication of possible space non-commutativity on the cosmic microwave background map is argued. (authors)

  8. Analysis techniques for background rejection at the Majorana Demonstrator

    Energy Technology Data Exchange (ETDEWEB)

    Cuestra, Clara [University of Washington; Rielage, Keith Robert [Los Alamos National Laboratory; Elliott, Steven Ray [Los Alamos National Laboratory; Xu, Wenqin [Los Alamos National Laboratory; Goett, John Jerome III [Los Alamos National Laboratory

    2015-06-11

    The MAJORANA Collaboration is constructing the MAJORANA DEMONSTRATOR, an ultra-low background, 40-kg modular HPGe detector array to search for neutrinoless double beta decay in 76Ge. In view of the next generation of tonne-scale Ge-based 0νββ-decay searches that will probe the neutrino mass scale in the inverted-hierarchy region, a major goal of the MAJORANA DEMONSTRATOR is to demonstrate a path forward to achieving a background rate at or below 1 count/tonne/year in the 4 keV region of interest around the Q-value at 2039 keV. The background rejection techniques to be applied to the data include cuts based on data reduction, pulse shape analysis, event coincidences, and time correlations. The Point Contact design of the DEMONSTRATOR's germanium detectors allows for significant reduction of gamma background.

  9. Removing Background Noise with Phased Array Signal Processing

    Science.gov (United States)

    Podboy, Gary; Stephens, David

    2015-01-01

    Preliminary results are presented from a test conducted to determine how well microphone phased array processing software could pull an acoustic signal out of background noise. The array consisted of 24 microphones in an aerodynamic fairing designed to be mounted in-flow. The processing was conducted using Functional Beam forming software developed by Optinav combined with cross spectral matrix subtraction. The test was conducted in the free-jet of the Nozzle Acoustic Test Rig at NASA GRC. The background noise was produced by the interaction of the free-jet flow with the solid surfaces in the flow. The acoustic signals were produced by acoustic drivers. The results show that the phased array processing was able to pull the acoustic signal out of the background noise provided the signal was no more than 20 dB below the background noise level measured using a conventional single microphone equipped with an aerodynamic forebody.

  10. Background simulations for the Large Area Detector onboard LOFT

    DEFF Research Database (Denmark)

    Campana, Riccardo; Feroci, Marco; Ettore, Del Monte

    2013-01-01

    and magnetic fields around compact objects and in supranuclear density conditions. Having an effective area of similar to 10 m(2) at 8 keV, LOFT will be able to measure with high sensitivity very fast variability in the X-ray fluxes and spectra. A good knowledge of the in-orbit background environment...... is essential to assess the scientific performance of the mission and optimize the design of its main instrument, the Large Area Detector (LAD). In this paper the results of an extensive Geant-4 simulation of the instrumentwillbe discussed, showing the main contributions to the background and the design...... an anticipated modulation of the background rate as small as 10 % over the orbital timescale. The intrinsic photonic origin of the largest background component also allows for an efficient modelling, supported by an in-flight active monitoring, allowing to predict systematic residuals significantly better than...

  11. Simulation of PEP-II Accelerator Backgrounds Using TURTLE

    CERN Document Server

    Barlow, Roger J; Kozanecki, Witold; Majewski, Stephanie; Roudeau, Patrick; Stocchi, Achille

    2005-01-01

    We present studies of accelerator-induced backgrounds in the BaBar detector at the SLAC B-Factory, carried out using a modified version ofthe DECAY TURTLE simulation package. Lost-particle backgrounds in PEP-II are dominated by a combination of beam-gas bremstrahlung, beam-gas Coulomb scattering, radiative-Bhabha events and beam-beam blow-up. The radiation damage and detector occupancy caused by the associated electromagnetic shower debris can limit the usable luminosity. In order to understand and mitigate such backgrounds, we have performed a full programme of beam-gas and luminosity-background simulations, that include the effects of the detector solenoidal field, detailed modelling of limiting apertures in both collider rings, and optimization of the betatron collimation scheme in the presence of large transverse tails.

  12. An EPIC Tale of the Quiescent Particle Background

    Science.gov (United States)

    Snowden, S.L.; Kuntz, K.D.

    2017-01-01

    Extended Source Analysis Software Use Based Empirical Investigation: (1) Builds quiescent particle background (QPB) spectra and images for observations of extended sources that fill (or mostly fill) the FOV i.e., annular background subtraction won't work. (2) Uses a combination of Filter Wheel Closed (FWC) and corner data to capture the spectral, spatial, and temporal variation of the quiescent particle background. New Work: (1) Improved understanding of the QPB (aided by adding a whole lot of data since 2008). (2) Significantly improved statistics (did I mention a LOT more data?). (3) Better characterization and identification of anomalous states. (4) Builds backgrounds for some anomalous state. (5) New efficient method for non-anomalous states.

  13. A time averaged background compensator for Geiger-Mueller counters

    International Nuclear Information System (INIS)

    Bhattacharya, R.C.; Ghosh, P.K.

    1983-01-01

    The GM tube compensator described stores background counts to cancel an equal number of pulses from the measuring channel providing time averaged compensation. The method suits portable instruments. (orig.)

  14. The Dortmund low background facility. Current status and recent developments

    Energy Technology Data Exchange (ETDEWEB)

    Goessling, Claus; Kroeninger, Kevin; Nitsch, Christian [Experimentelle Physik IV, TU Dortmund, 44221 Dortmund (Germany)

    2016-07-01

    The Dortmund Low Background Facility (DLB) is a low-background gamma ray spectrometry system with an artificial overburden. The overburden of ten meters of water equivalent, in combination with a multi-layer lead castle and an active muon veto are shielding a high-purity germanium detector of 60 % relative efficiency. The background level is remarkably low compared to a conventional spectrometer system without special shielding and enables sensitivities well below 1 Bq/kg. Thus, material screening measurements as well as environmental monitoring measurements are possible on an easy-accessible location above ground at the campus of the Technische Universitaet Dortmund. The integral background count rate between 40 keV and 2700 keV is 2.528±0.004 counts/kg/min, which is comparable to systems that are situated below ground. In the talk, an overview of the current status of the DLB is given and recent developments are presented.

  15. Foreground-background segmentation and attention: a change blindness study.

    Science.gov (United States)

    Mazza, Veronica; Turatto, Massimo; Umiltà, Carlo

    2005-01-01

    One of the most debated questions in visual attention research is what factors affect the deployment of attention in the visual scene? Segmentation processes are influential factors, providing candidate objects for further attentional selection, and the relevant literature has concentrated on how figure-ground segmentation mechanisms influence visual attention. However, another crucial process, namely foreground-background segmentation, seems to have been neglected. By using a change blindness paradigm, we explored whether attention is preferentially allocated to the foreground elements or to the background ones. The results indicated that unless attention was voluntarily deployed to the background, large changes in the color of its elements remained unnoticed. In contrast, minor changes in the foreground elements were promptly reported. Differences in change blindness between the two regions of the display indicate that attention is, by default, biased toward the foreground elements. This also supports the phenomenal observations made by Gestaltists, who demonstrated the greater salience of the foreground than the background.

  16. Separate effects of background and illumination on lightness

    Directory of Open Access Journals (Sweden)

    Zdravković Sunčica

    2007-01-01

    Full Text Available Four experiments attempted to establish an effect of context on lightness. Lightness is one of the dimensions of color and it varies from black to white. Most of our stimuli were inspired by simultaneous lightness contrast illusion. First two experiments contrast the size of an effect produced by the change of background color vs. the change in illumination. The third experiment deals with different type of illusions, where the effect is obtained through the appearance of multiple illumination levels. The last experiment takes into account the ratio of the target and the background. The results reveal the size of effects produced separately by the background color and illumination level and suggest the prime importance of background. Also there are other factors such as reflectance range in the scene, incremental and decremental targets, and 2D vs. 3D representation.

  17. Simulation of off-energy electron background in DELPHI

    CERN Document Server

    Falk, E; Von Holtey, Georg

    1997-01-01

    Monte Carlo simulations of off-energy electron background in the DELPHI luminometer STIC are reported. The study simulates the running conditions at 68 GeV with and without bunch trains. The electrostatic separators, which create the vertical separation bumps for the the bunch trains, cause a high concentration of background in the vertical plane. The simulations are compared to LEP data taken under similar running conditions. A comparison between the simulated running conditions at 68 GeV and those of the new LEP2 beam optics at 80.5 GeV is made. Moreover, the study investigates background components entering STIC elsewhere that through the front of the detector, and a significant portion is found to enter either from the back or from below. Possible improvements of the background situation are also discussed.

  18. Lorentz-violating electrodynamics and the cosmic microwave background.

    Science.gov (United States)

    Kostelecký, V Alan; Mewes, Matthew

    2007-07-06

    Possible Lorentz-violating effects in the cosmic microwave background are studied. We provide a systematic classification of renormalizable and nonrenormalizable operators for Lorentz violation in electrodynamics and use polarimetric observations to search for the associated violations.

  19. Linear polarized fluctuations in the cosmic microwave background

    International Nuclear Information System (INIS)

    Partridge, R.B.; Nowakowski, J.; Martin, H.M.

    1988-01-01

    We report here limits on the linear (and circular) polarization of the cosmic microwave background on small angular scales, 18''≤ θ ≤ 160''. The limits are based on radio maps of Stokes parameters and polarisation (linear and circular). (author)

  20. Prospects for the direct detection of the cosmic neutrino background

    International Nuclear Information System (INIS)

    Ringwald, Andreas

    2009-01-01

    The existence of a cosmic neutrino background - the analogue of the cosmic microwave background - is a fundamental prediction of standard big bang cosmology. Up to now, the observational evidence for its existence is rather indirect and rests entirely on cosmological observations of, e.g., the light elemental abundances, the anisotropies in the cosmic microwave background, and the large scale distribution of matter. Here, we review more direct, weak interaction based detection techniques for the cosmic neutrino background in the present epoch and in our local neighbourhood. We show that, with current technology, all proposals are still off by some orders of magnitude in sensitivity to lead to a guaranteed detection of the relic neutrinos. The most promising laboratory search, based on neutrino capture on beta decaying nuclei, may be done in future experiments designed to measure the neutrino mass through decay kinematics.