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Sample records for co-60 sobre vyns

  1. Fate of Co-60 at a Sludge Land Application Site

    SciTech Connect

    Smith, Michael A.; Larsen, I. L.; Fentiman, Audeen W.

    2008-08-28

    Vertical distributions of Co-60 are determined in soil cores obtained from a 10-hectare grassland, where anaerobically-digested sludge was applied by surface spraying from 1986 to 1995 on the U.S. Department of Energy’s Oak Ridge Reservation. These results, along with historical application records, are used to estimate vertical-migration rates and perform a mass balance. The presence of Co-60 results solely from the sludge-application process. Soil, vegetation, and surface-water samples were collected. Eleven soil cores were sectioned into 3-cm increments and analyzed by gamma-ray spectrometry. No Co-60 was detected in the vegetation or water samples. The downward migration rate of Co-60 in the upper 15 cm of soil ranged from 0.50 to 0.73 cm/yr. About 98 percent, 0.020 ± 0.011 Bq/cm2, of Co-60 remained in the upper 15 cm of soil, which compared favorably with the expected Co-60 activity based on historical records of 0.019 ± 0.010 Bq/cm2.

  2. Lesson learned from Co-60 accident in Thailand.

    PubMed

    Thongpraparn, T; Chaudakshetrin, P; Buranapong, P

    2002-12-01

    The causes and consequences of a Co-60 radiation accident in Samutprakarn Province, Thailand, were scrutinized to learn lessons aimed at preventing future radiation accidents. "Orphan sources" may end up in scrapyards. An out-of-use Co-60 medical teletherapy source, left unattended in a disused parking area belonging to a Medical Dealer, was stolen and sold to a scrap dealer in Samutprakarn Province at the end of January 2000. Because of its valuable appearance, a number of workers in the scrap trade who were not aware of radiation hazards managed to dismantle all parts. The Co-60 source was removed and left unshielded among pieces of scrap metal in the yard of the scrap shop. Some workers immediately became sick. Eighteen days later when they went to a local hospital their symptoms were recognized as radiation sickness and the incident was reported to the Office of Atomic Energy for Peace (OAEP) in Thailand. The unshielded source, with an estimated activity of 15.7 TBq (425 Ci), was retrieved soon after by an emergency team and placed in safe storage at the OAEP premises. Ten victims developed radiation sickness symptoms, of which three died soon after the accident. The accident alarmed the public, and has raised national concerns. The accident is similar in some ways to the 1987 radiation accident at Goiania, Brazil, involving a Cs-137 radiotherapy source. If not properly disposed of orphan radiation sources can lead to serious injury or even death. The accident highlights the need for security of spent high activity sources and the importance of regulatory controls. PMID:12859145

  3. Functionalization and magnetization of carbon nanotubes using Co-60 gamma-ray irradiation

    NASA Astrophysics Data System (ADS)

    Chen, C. Y.; Fu, M. J.; Tsai, C. Y.; Lin, F. H.; Chen, K. Y.

    2014-10-01

    Functionalized magnetic carbon nanotubes (CNTs) can be used in the biological and biomedical fields as biosensors, drug delivery systems, etc., which makes research into processes for manufacturing modified CNTs quite important. In this paper, Co-60 gamma irradiation is shown to be an effective tool for fabricating functionalized and magnetized CNTs. After the Co-60 gamma irradiation, the presence of carboxylic functional groups on the CNT walls was confirmed by their Fourier transform infrared spectra, and the presence of Fe3O4 was verified by the X-ray diffraction patterns. The functionalized and magnetized CNTs produced using Co-60 gamma irradiation have excellent dispersion properties. The techniques for functionalizing and magnetizing CNTs are introduced in this paper, and applications of the modified CNTs will be reported after more data are gathered.

  4. NOTE: Monte Carlo dosimetric study of the BEBIG Co-60 HDR source

    NASA Astrophysics Data System (ADS)

    Ballester, F.; Granero, D.; Pérez-Calatayud, J.; Casal, E.; Agramunt, S.; Cases, R.

    2005-11-01

    Although not as widespread as Ir-192, Co-60 is also available on afterloading equipment devoted to high dose rate brachytherapy, mainly addressed to the treatment of gynaecological lesions. The purpose of this study is to obtain the dosimetric parameters of the Co-60 source used by the BEBIG MultiSource remote afterloader (BEBIG GmbH, Germany) for which there are no dosimetric data available in the literature. The Monte Carlo code GEANT4 has been used to obtain the TG43 parameters and the 2D dose rate table in Cartesian coordinates of the BEBIG Co-60 HDR source. The dose rate constant, radial dose function and anisotropy function have been calculated and are presented in a tabular form as well as a detailed 2D dose rate table in Cartesian coordinates. These dosimetric datasets can be used as input data and to validate the treatment planning system calculations.

  5. Monte Carlo dosimetric study of the BEBIG Co-60 HDR source.

    PubMed

    Ballester, F; Granero, D; Pérez-Calatayud, J; Casal, E; Agramunt, S; Cases, R

    2005-11-01

    Although not as widespread as Ir-192, Co-60 is also available on afterloading equipment devoted to high dose rate brachytherapy, mainly addressed to the treatment of gynaecological lesions. The purpose of this study is to obtain the dosimetric parameters of the Co-60 source used by the BEBIG MultiSource remote afterloader (BEBIG GmbH, Germany) for which there are no dosimetric data available in the literature. The Monte Carlo code GEANT4 has been used to obtain the TG43 parameters and the 2D dose rate table in Cartesian coordinates of the BEBIG Co-60 HDR source. The dose rate constant, radial dose function and anisotropy function have been calculated and are presented in a tabular form as well as a detailed 2D dose rate table in Cartesian coordinates. These dosimetric datasets can be used as input data and to validate the treatment planning system calculations. PMID:16237230

  6. Increasing efficiency of BEAMnrc-simulated Co-60 beams using directional source biasing

    SciTech Connect

    Walters, B. R. B.

    2015-10-15

    Purpose: This study describes the implementation of a directional source biasing (DSB) scheme for efficiently simulating Cobalt-60 treatment heads using the BEAMnrc Monte Carlo code. Previous simulation of Co-60 beams with BEAMnrc was impractical because of the time required to track photons not directed into the treatment field and to simulate secondary charged particles. Methods: In DSB, efficiency is increased by splitting each photon emitted by the Co-60 source a user-defined number of times. Only those split primary photons directed into a user-defined splitting field (encompassing the treatment field) are sampled, yielding many low-weight photons directed into the field. Efficiency can be further increased by taking advantage of radial symmetry at the top of the treatment head to reduce the number of split primary photons tracked in this portion. There is also an option to generate contaminant electrons in DSB. Results: The DSB scheme in BEAMnrc increases the photon fluence calculation efficiency in a 10 × 10 cm{sup 2} Co-60 beam by a factor of 1800 with a concurrent increase in contaminant electron fluence calculation efficiency by a factor of 1200. Implementation of DSB in beampp, a C++ code for accelerator simulations based on EGSnrc and the C++ class library, egspp, increases photon fluence efficiency by a factor of 2800 and contaminant electron fluence efficiency by a factor of 1600. Optimum splitting numbers are in the range of 20 000–40 000. For dose calculations in a water phantom (0.5 × 0.5 × 0.5 cm{sup 3} voxels) this translates into a factor of ∼400 increase in dose calculation efficiency (all doses > 0.5 × D{sub max}). An example calculation of the ratio of dose to water to dose to chamber (the basis of the beam quality correction factor) to within 0.2% in a realistic chamber using a full simulation of a Co-60 treatment head as a source indicates the practicality of Co-60 simulations with DSB. Conclusions: The efficiency improvement

  7. The research of using Co-60 γ ray to sterilize different mediums for edible fungus

    NASA Astrophysics Data System (ADS)

    Guozhu, Li; Zhenqian, Guan; Hengshou, Zhao

    1993-10-01

    The present experiment has been carried out by using different dosage of Co—60 γ ray for radiation sterilization of five kinds of cultural materials of edible fungus, The results indicated that sterilization dosage of sawdust is 22 kGy. that of cotton—seed shell and the rest are 26 kGy. We conclude that using Co-60 γ ray to sterilize the cultura 1 materials of edible fungus is a secure and saving labor and energy new method which could sterilize thoroughly.

  8. Monte Carlo dosimetric study of the Flexisource Co-60 high dose rate source

    PubMed Central

    Granero, Domingo; Perez-Calatayud, Jose; Ballester, Facundo

    2012-01-01

    Purpose Recently, a new HDR 60Co brachytherapy source, Flexisource Co-60, has been developed (Nucletron B.V. Veenendaal, The Netherlands). This study aims to obtain dosimetric data for this source for its use in clinical practice as required by AAPM and ESTRO. Material and methods Two Monte Carlo radiation transport codes were used: Penelope2008 and GEANT4. The source was centrally-positioned in a 100 cm radius water phantom. Absorbed dose and collisional kerma were obtained using 0.01 cm (close) and 0.1 cm (far) sized voxels to provide high-resolution dosimetry near (far from) the source. Dose rate distributions obtained with the two Monte Carlo codes were compared. Results and Discussion Simulations performed with those two radiation transport codes showed an agreement typically within 0.2% for r > 0.8 cm and up to 2% closer to the source. Detailed results of dose distributions are being made available. Conclusions Dosimetric data are provided for the new Flexisource Co-60 source. These data are meant to be used in treatment planning systems in clinical practice. PMID:23346138

  9. Radiation Field of Packages Carrying Spent Co-60 Radioactive Sources - 12437

    SciTech Connect

    Marzo, Giuseppe A.; Giorgiantoni, Giorgio; Sepielli, Massimo

    2012-07-01

    Among the diverse radioactive sources commonly exploited in medical and industrial applications, Co- 60 is increasingly used as strong gamma emitter. Over time, source manufacturers favored Co-60 as opposed to other gamma emitters because its relatively short half-life (5.27 year) that minimizes issues related to the management of disused sources. Disused Co-60 sources can retain a significant amount of radioactivity (from hundreds of MBq to several GBq) that still poses safety concerns on their handling and transportation. In this context a detailed knowledge of their radiation field would provide the necessary information for taking actions in preventing unnecessary doses to the workers and the population by optimizing transportation procedures and handling operations. We modeled the geometry and the materials constituting a transportation packaging of a spent Co-60 source which had an original maximum activity of a few GBq and was enclosed in a small lead irradiator. Then we applied a Monte Carlo transport code (MCNP5) for tracking down the gamma photons emitted by the source, including the secondary photons resulting by the interaction of the source photons with the surrounding materials. This allowed for the evaluation of the radiation field inside and outside the packaging, and the corresponding equivalent dose useful for checking the compliance with the regulations and the health risk of possible radiation exposure. We found that a typical 60-liters drum carrying a spent Co-60 source, enclosed in its original irradiator, with a residual activity of 300 MBq could already overcome an equivalent dose of 0.2 mSv/h on the drum external surface, which is the maximum equivalent dose at any point of the surface for this packaging as prescribed by local regulations. This condition is even more apparent when the source is slightly displaced with respect to the rotation axis of the drum, an easily occurring condition for sources not properly packaged, generating non

  10. Anti-LPS antibodies reduce endotoxemia in whole body Co-60 irradiated primates - A preliminary report

    SciTech Connect

    Wells, M.T.; Gaffin, S.L.; Wessels, B.C.; Brock-Utne, J.G.; Jordaan, J.P. )

    1990-09-01

    A previously established primate model was used to evaluate the role of lipopolysaccharide (LPS, endotoxin) in radiation sickness. Vervet monkeys were Co-60 irradiated with an LD100 exposure and had periodic blood samples taken for the determination of LPS and anti-LPS lgG antibodies and for bacteriological studies. On day 2 postirradiation, primates were treated with either sterile 0.9 percent saline, or equine anti-LPS hyperimmune plasma, or tripotassium-dicitrato-bismuthate (Denol). Results indicate that anti-LPS-treated animals survived significantly longer than both the other groups and, since LPS may cause nausea, vomiting, diarrhea, anorexia, and headaches, it is suggested that Anti-LPS administration may be of value in reducing plasma LPS concentration in humans and improving their performance and survivability. 24 refs.

  11. Preliminary design of betavoltaic battery using Co-60 and Pm-147 with GaAs substrate

    NASA Astrophysics Data System (ADS)

    Waris, A.; Kusumawati, Y.; Alfarobi, A. S.; Aji, I. K.; Basar, K.

    2016-03-01

    Battery is very important for the present daily life, especially for portable devices. The longer utilization time the better performance of battery. Betavoltaic battery is a device that converts energy from beta decays of radioactive nuclide into electric current. One of merits of the later battery is the life time that can be more than ten years without recharging. To develop the betavoltaic battery for energy source of portable devices we have performed a preliminary simulation design of betavoltaic battery using Pm-147 and Co-60 a beta emitter radionuclides with n-GaAs substrate. From the results we found that the combination of Pm-147 with n-GaAs substrate results in 9.0% of efficiency and higher output current compared to references.

  12. Dosimetric properties of dysprosium doped calcium magnesium borate glass subjected to Co-60 gamma ray

    NASA Astrophysics Data System (ADS)

    Omar, R. S.; Wagiran, H.; Saeed, M. A.

    2016-01-01

    Thermoluminescence (TL) dosimetric properties of dysprosium doped calcium magnesium borate (CMB:Dy) glass are presented. This study is deemed to understand the application of calcium as the modifier in magnesium borate glass with the presence of dysprosium as the activator to be performed as TL dosimeter (TLD). The study provides fundamental knowledge of a glass system that may lead to perform new TL glass dosimetry application in future research. Calcium magnesium borate glass systems of (70-y) B2O3 - 20 CaO - 10 MgO-(y) Dy2O3 with 0.05 mol % ≤ y ≤ 0.7 mol % of dyprosium were prepared by melt-quenching technique. The amorphous structure and TL properties of the prepared samples were determined using powder X-ray diffraction (XRD) and TL reader; model Harshaw 4500 respectively. The samples were irradiated to Co-60 gamma source at a dose of 50 Gy. Dosimetric properties such as annealing procedure, time temperature profile (TTP) setting, optimization of Dy2O3 concentration of 0.5 mol % were determined for thermoluminescence dosimeter (TLD) reader used.

  13. UNDERWATER ANALYSIS OF IRRADIATED REACTOR SLUGS FOR Co-60 AND OTHER RADIONUCLIDES AT THE SAVANNAH RIVER SITE

    SciTech Connect

    CASELLA, VITO

    2004-05-10

    Co-60 was produced in the Savannah River Site (SRS) reactors in the 1970s, and the irradiated cobalt reactor slugs were stored in a reactor basin at SRS. Since the activity rates of these slugs were not accurately known, assaying was required. A sodium iodide gamma detector was placed above a specially designed air collimator assembly, so that the slug was eight to nine feet from the detector and was shielded by the basin water. Also, 18 curium sampler slugs, used to produce Cm-244 from Pu-239, were to be disposed of with the cobalt slugs. The curium slugs were also analyzed with a High Purity Germanium (HPGE) detector in an attempt to identify any additional radionuclides produced from the irradiation. Co-60 concentrations were determined for reactor disassembly basin cobalt slugs and the 18 curium sampler slugs. The total Co-60 activity of all of the assayed slugs in this work summed to 31,783 curies on 9/15/03. From the Co-60 concentrations of the curium sampler slugs, the irradiation flux was determined for the known irradiation time. The amounts of Pu-238,-239,-240,-241,-242; Am-241,-243; and Cm-242,-244 produced were then obtained based on the original amount of Pu-239 irradiated.

  14. Decommissioning of a nuclear power plant: determination of site-specific sorption coefficients for Co-60 and Cs-137.

    PubMed

    Delakowitz, B; Meinrath, G

    1998-01-01

    Assessment of radiological risks in strategies for decommissioning of nuclear installations have to consider not only technical concepts such as cutting and decontamination techniques but, even more important, requirements for input of reliable information on the hydrological situation and retardation capabilities of relevant radionuclides specific to the respective decommissioning operation. In this paper we describe appropriate methods for obtaining site-specific sorption data and present results achieved from a case study performed as a commercial contractual work preliminary to the planned decommissioning of a nuclear power plant. A detailed mineralogical study of the sediment used in our sorption experiment highlights the necessity of a thorough sample homogenization and characterization. Batch experiments using radiotracer techniques for the determination of site-specific sorption coefficients show significant retardation for Co-60 and Cs-137 after only 2 h of equilibration between the preconditioned groundwater and sediment. Sorption is more effective in the groundwater of a deeper aquifer containing a higher amount of colloidal clay (illite) particles < 0.63 micron. The Co-60 radiotracer is more completely sorbed than the Cs-137 radiotracer. Equilibration of radionuclide distribution is slow, particularly for Co-60. Presence of EDTA reduces sorption of Co-60 efficiently while Cs-137 sorption remains unaffected. PMID:10089594

  15. Measurement of Cerenkov Radiation Induced by the Gamma-Rays of Co-60 Therapy Units Using Wavelength Shifting Fiber

    PubMed Central

    Jang, Kyoung Won; Shin, Sang Hun; Kim, Seon Geun; Kim, Jae Seok; Yoo, Wook Jae; Ji, Young Hoon; Lee, Bongsoo

    2014-01-01

    In this study, a wavelength shifting fiber that shifts ultra-violet and blue light to green light was employed as a sensor probe of a fiber-optic Cerenkov radiation sensor. In order to characterize Cerenkov radiation generated in the developed wavelength shifting fiber and a plastic optical fiber, spectra and intensities of Cerenkov radiation were measured with a spectrometer. The spectral peaks of light outputs from the wavelength shifting fiber and the plastic optical fiber were measured at wavelengths of 500 and 510 nm, respectively, and the intensity of transmitted light output of the wavelength shifting fiber was 22.2 times higher than that of the plastic optical fiber. Also, electron fluxes and total energy depositions of gamma-ray beams generated from a Co-60 therapy unit were calculated according to water depths using the Monte Carlo N-particle transport code. The relationship between the fluxes of electrons over the Cerenkov threshold energy and the energy depositions of gamma-ray beams from the Co-60 unit is a near-identity function. Finally, percentage depth doses for the gamma-ray beams were obtained using the fiber-optic Cerenkov radiation sensor, and the results were compared with those obtained by an ionization chamber. The average dose difference between the results of the fiber-optic Cerenkov radiation sensor and those of the ionization chamber was about 2.09%. PMID:24755521

  16. Measurement of Cerenkov radiation induced by the gamma-rays of Co-60 therapy units using wavelength shifting fiber.

    PubMed

    Jang, Kyoung Won; Shin, Sang Hun; Kim, Seon Geun; Kim, Jae Seok; Yoo, Wook Jae; Ji, Young Hoon; Lee, Bongsoo

    2014-01-01

    In this study, a wavelength shifting fiber that shifts ultra-violet and blue light to green light was employed as a sensor probe of a fiber-optic Cerenkov radiation sensor. In order to characterize Cerenkov radiation generated in the developed wavelength shifting fiber and a plastic optical fiber, spectra and intensities of Cerenkov radiation were measured with a spectrometer. The spectral peaks of light outputs from the wavelength shifting fiber and the plastic optical fiber were measured at wavelengths of 500 and 510 nm, respectively, and the intensity of transmitted light output of the wavelength shifting fiber was 22.2 times higher than that of the plastic optical fiber. Also, electron fluxes and total energy depositions of gamma-ray beams generated from a Co-60 therapy unit were calculated according to water depths using the Monte Carlo N-particle transport code. The relationship between the fluxes of electrons over the Cerenkov threshold energy and the energy depositions of gamma-ray beams from the Co-60 unit is a near-identity function. Finally, percentage depth doses for the gamma-ray beams were obtained using the fiber-optic Cerenkov radiation sensor, and the results were compared with those obtained by an ionization chamber. The average dose difference between the results of the fiber-optic Cerenkov radiation sensor and those of the ionization chamber was about 2.09%. PMID:24755521

  17. Effect of Co-60 gamma radiation on the mechanical properties of epoxy blends and epoxy-graphite fiber interface

    SciTech Connect

    Netravali, A.N.; Manji, A. )

    1991-06-01

    The effect of Co-60 gamma radiation of up to 100 Mrads on an IM6-G graphite fiber-epoxy interface was studied using the single-fiber-composite (SFC) technique. Flexible epoxy blends were formulated using DGEBA based and polyglycol diepoxide epoxies which were cured with aliphatic and aromatic curing agents. Bulk epoxy specimens and graphite fibers were tension tested to obtain their tensile properties. The fragment length distribution from SFC tests, single fiber strength data, and a Monte Carlo simulation of Poisson/Weibull model for fiber strength and flaws were used to obtain the effective interfacial shear strength values. The results indicate that while graphite fiber strength is not affected by radiation, the tensile properties of the epoxies used are adversely affected by the radiation. The interfacial shear strength, however, increases significantly with the radiation dose. 36 refs.

  18. Verification of Entrance Dose Measurements with Thermoluminescent Dosimeters in Conventional Radiotherapy Procedures Delivered with Co-60 Teletherapy Machine

    PubMed Central

    Evwierhurhoma, OB; Ibitoye, ZA; Ojieh, CA; Duncan, JTK

    2015-01-01

    Background: The use of in vivo dosimetry with thermolumiscent dosimeters (TLDs) as a veritable means of quality control in conventional radiotherapy procedures was determined in this work. Aim: The objective of this study was to determine the role of in vivo dosimetry with thermoluminescent dosimeters (TLDs) as part of quality control and audit in conventional radiotherapy procedures delivered with Co-60 teletherapy machine. Subjects and Methods: Fifty-seven patients with cancers of the breast, pelvis, head and neck were admitted for this study. TLD system at the Radiation Monitoring and Protection Centre, Lagos State University, Ojo, Lagos-Nigeria was used for the in vivo entrance dose readings. All patients were treated with Co-60 (T780c) teletherapy machine at 80 cm source to surface distance located at Eko Hospitals, Lagos. Two TLDs were placed on the patient surface within 1 cm from the center of the field of treatment. Build-up material made of paraffin wax with a density of 0.939 g/cm3 and a thickness 0.5 cm was placed on top of the TLDs. A RADOS RE 200 TLD reader was used to read out the TLDs over 12 s and at a temperature of 300°C. Results: The results showed that there was no significant difference between the expected dose and measured dose of breast (P = 0.11), H and N (P = 0.52), and pelvis (P = 0.31) patients. Furthermore, percentage difference between expected dose and measured dose of the three treatment sites were not significantly different (P = 0.11). More so, 88.9% (16/18) treated breast, 91.3% (21/23) pelvis, and 86.7% (13/15) H and N patients had percentage deviation difference less than 5%. In general, 89.3% (50/56) patients admitted for this study had their percentage deviation difference below 5% recommended standard limit. Conclusion: The values obtained establish that there are no major differences from similar studies reported in literature. This study was also part of quality control and audit of the radiotherapy procedures in the

  19. Depth distribution of H-3, C-14 and Co-60 in decommissioning of the biological shielding concrete of KRR-2

    SciTech Connect

    Hong, S.B.; Kim, H.R.; Chung, R.H.; Chung, K.H.; Park, J.H.

    2007-07-01

    The depth distributions of the gamma emitting nuclides, H-3 and C-14 activities were characterized for the activated biological shielding concrete from a decommissioning of Korea Research Reactor-2(TRIGA Mark-II) by using a commercially available tube furnace and a liquid scintillation counter. The HTO vapor and {sup 14}CO{sub 2} gas generated from the tube furnace were trapped in HNO{sub 3} and Carbosorb bubbler, respectively. The H-3 and C-14 activities were measured by the liquid scintillation counter. The specific activities of H-3 and C-14 were calculated by considering the concrete mass and the recovery factor of the tube furnace. The detection limits for H-3 and C-14 were 0.048 and 0.028 Bq/g respectively. The specific activity of the H-3 and C-14 tends to decrease exponentially as the depth of the concrete becomes deeper from the surface. In addition, the H-3 and C-14 activities were in good agreement with the Co-60 activities analyzed for the biological shielding concrete of KRR-2. (authors)

  20. Calculation and measurement of the dose to points outside the primary beam for CO-60 gamma radiation

    SciTech Connect

    Van Der Giessen, P.H.; Hurkmans, C.W.

    1993-10-20

    In radiation therapy one sometimes needs to estimate the dose to points in the body outside the primary beam. Therefore a generalized model is developed to calculate this dose with reasonable accuracy. Measurements were made for a cobalt beam to determine separately the contribution of leakage radiation, radiation scattered from the collimator, scattered from the floor and radiation scattered inside the patient. The radiation scattered in the patient shows a strong dependence on field size and distance to the beam axis and is predominant only at short distances. The radiation scattered from the collimator also depends strongly on distance and field size and is more important than the leakage radiation. With appropriate factors, correcting for patient dimensions and field shape, the total dose outside the primary beam can be calculated with an accuracy better than {+-}30%. The results are in accordance with published data. Using the measured data it is possible to calculate the dose at any point of the body outside the primary beam for Co-60 gamma radiation. The accuracy is considered to be adequate for risk assessment. 13 refs., 7 figs., 2 tabs.

  1. Total integrated dose testing of solid-state scientific CD4011, CD4013, and CD4060 devices by irradiation with CO-60 gamma rays

    NASA Technical Reports Server (NTRS)

    Dantas, A. R. V.; Gauthier, M. K.; Coss, J. R.

    1985-01-01

    The total integrated dose response of three CMOS devices manufactured by Solid State Scientific has been measured using CO-60 gamma rays. Key parameter measurements were made and compared for each device type. The data show that the CD4011, CD4013, and CD4060 produced by this manufacturers should not be used in any environments where radiation levels might exceed 1,000 rad(Si).

  2. Total integrated dose testing of solid-state scientific CD4011, CD4013, and CD4060 devices by irradiation with CO-60 gamma rays

    SciTech Connect

    Dantas, A.R.V.; Gauthier, M.K.; Coss, J.R.

    1985-05-01

    The total integrated dose response of three CMOS devices manufactured by Solid State Scientific has been measured using CO-60 gamma rays. Key parameter measurements were made and compared for each device type. The data show that the CD4011, CD4013, and CD4060 produced by this manufacturers should not be used in any environments where radiation levels might exceed 1,000 rad(Si).

  3. A comparison of 4 MeV Proton and Co-60 gamma irradiation induced degradation in the electrical characteristics of N-channel MOSFETs

    NASA Astrophysics Data System (ADS)

    Anjum, Arshiya; Vinayakprasanna, N. H.; Pradeep, T. M.; Pushpa, N.; Krishna, J. B. M.; Gnana Prakash, A. P.

    2016-07-01

    N-channel depletion MOSFETs were irradiated with 4 MeV Proton and Co-60 gamma radiation in the dose range of 100 krad(Si) to 100 Mrad(Si). The electrical characteristics of MOSFET such as threshold voltage (Vth), density of interface trapped charges (ΔNit), density of oxide trapped charges (ΔNot), transconductance (gm), mobility (μ), leakage current (IL) and drain saturation current (ID Sat) were studied as a function of dose. A considerable increase in ΔNit and ΔNot and decrease in Vth,gm, μ, and ID Sat was observed after irradiation. The results of 4 MeV Proton irradiation were compared with that of Co-60 gamma radiation and it is found that the degradation is more for the devices irradiated with 4 MeV Protons when compared with the Co-60 gamma radiation. This indicates that Protons induce more trapped charges in the field oxide region when compared to the gamma radiation.

  4. Modelling and Monte Carlo organ dose calculations for workers walking on ground contaminated with Cs-137 and Co-60 gamma sources

    PubMed Central

    Han, Bin; Zhang, Juying; Na, Yong Hum; Caracappa, Peter F.; Xu, X. George

    2010-01-01

    A pair of walking phantoms was developed from deformable mesh phantoms to represent individuals walking on contaminated ground. The Monte Carlo N-particle extended version code was used to calculate organ doses from ground contamination scenarios involving parallel and isotropic planar sources of Cs-137 and Co-60 with concentrations of 30 kBqm−2. For the parallel plane source case, the organ doses were up to 78 % greater for walking phantoms than those for the standing phantoms. The dose difference is because the widely open legs during walking provide less shielding to several organs, especially the kidneys, ovaries and liver, from parallel sources. The effective doses of the walking phantoms were on average 15 % higher than the standing phantoms. On the other hand, when isotropic planar sources were considered, no significant dose difference was observed. This study demonstrated the feasibility of using deformable phantoms to represent realistic postures for organ dose calculations in environmental dosimetry studies. PMID:20663852

  5. Dosimetry of interface region near closed air cavities for Co-60, 6 MV and 15 MV photon beams using Monte Carlo simulations.

    PubMed

    Joshi, Chandra P; Darko, Johnson; Vidyasagar, P B; Schreiner, L John

    2010-04-01

    Underdosing of treatment targets can occur in radiation therapy due to electronic disequilibrium around air-tissue interfaces when tumors are situated near natural air cavities. These effects have been shown to increase with the beam energy and decrease with the field size. Intensity modulated radiation therapy (IMRT) and tomotherapy techniques employ combinations of multiple small radiation beamlets of varying intensities to deliver highly conformal radiation therapy. The use of small beamlets in these techniques may therefore result in underdosing of treatment target in the air-tissue interfaces region surrounding an air cavity. This work was undertaken to investigate dose reductions near the air-water interfaces of 1x1x1 and 3x3x3 cm(3) air cavities, typically encountered in the treatment of head and neck cancer utilizing radiation therapy techniques such as IMRT and tomotherapy using small fields of Co-60, 6 MV and 15 MV photons. Additional investigations were performed for larger photon field sizes encompassing the entire air-cavity, such as encountered in conventional three dimensional conformal radiation therapy (3DCRT) techniques. The EGSnrc/DOSXYZnrc Monte Carlo code was used to calculate the dose reductions (in water) in air-water interface region for single, parallel opposed and four field irradiations with 2x2 cm(2) (beamlet), 10x2 cm(2) (fan beam), 5x5 and 7x7 cm(2) field sizes. The magnitude of dose reduction in water near air-water interface increases with photon energy; decreases with distance from the interface as well as decreases as the number of beams are increased. No dose reductions were observed for large field sizes encompassing the air cavities. The results demonstrate that Co-60 beams may provide significantly smaller interface dose reductions than 6 MV and 15 MV irradiations for small field irradiations such as used in IMRT and tomotherapy. PMID:20589116

  6. Effects of Substerilization Doses of Co60 Gamma Radiation on the Cold-Storage Life Extension of Shucked Soft-Shelled Clams and Haddock Fillets

    PubMed Central

    Masurovsky, E. B.; Goldblith, S. A.; Nickerson, J. T. R.

    1963-01-01

    Total aerobic-facultative and anaerobic (clostridia) macrocolony count data are presented, with analysis and interpretation, for both haddock fillets and shucked soft-shelled clams which received doses of from 50,000 to 800,000 rad of Co60 gamma rays. These data indicated that haddock fillets may be maintained in good condition at refrigeration temperatures above freezing for about 1 week at 6 C, and approximately 2 weeks at 0 C, when treated with from 50,000 to 150,000 rad of ionizing radiation. In the dose range from 200,000 to 350,000 rad, the storage life may be extended up to some 2 weeks at 6 C, and 3 weeks at 0 C. Treatments in the dose range from 400,000 to 500,000 rad may defer spoilage for about 1 month, and doses of 550,000 to 650,000 rad afford protection against bacterial spoilage up to approximately 1.5 months. At the high substerilization doses of 700,000 to 800,000 rad, haddock fillets may be held for from 2 to 3 months in refrigerated storage before becoming unfit for marketing and consumption. Shucked soft-shelled clams can be held for about 2.5 weeks at 0 C and close to 12 days at 6 C, when given low substerilization doses of from 50,000 to 150,000 rad of ionizing radiation. At doses of from 200,000 to 350,000 rad, the clams may be preserved effectively for periods up to 3 weeks at 0 or 6 C, and some 6 weeks at these temperatures with doses of about 450,000 rad. With treatments of 500,000 to 600,000 rad, the storage life may be extended for some 2 months, and at doses of 650,000 to 800,000 rad the shucked clams remain in a good state of preservation for up to 3 months at temperatures of 0 to 6 C. Thus, it would appear that shucked soft-shelled clams may be maintained for significantly longer periods in refrigerated storage than haddock fillets when the same radiation treatments are applied to each product. Clostridia levels in both products were relatively low initially, and were reduced significantly by the gamma rays at the doses studied

  7. Water equivalence study of some phantoms based on effective photon energy, effective atomic numbers and electron densities for clinical MV X-ray and Co-60 γ-ray beams

    NASA Astrophysics Data System (ADS)

    Kurudirek, Murat

    2013-02-01

    A previously proposed procedure has been applied to some water equivalent phantoms namely PMMA, Polystyrene, Solid Water (WT1), RW3 and ABS for the first time to compute effective photon energy (Eeff), effective atomic numbers (Zeff) and electron densities (neeff) for different MV X-ray beams and Co-60 gamma beam which are heterogeneous in energy. For the purpose of the present investigation, effective atomic cross-sections of the given materials have been determined first to obtain effective photon energies which were further used for calculation of Zeff and neeff. Similar procedure was adopted for Co-60 γ-rays to check the validity of the present method. Results were found to be quite satisfactory. When it comes to the water equivalence, the Eeff results showed that the RW3 and ABS phantoms are more effective for 6 MV beam whereas RW3 and Polystyrene are more effective for 15 MV and Co-60 beams, respectively. The ABS and WT1 phantoms have better water equivalences than the others according to the Zeff and neeff results, respectively.

  8. Formulae for TAR and SAR calculation for Co-60 beam.

    PubMed

    Tripathi, U B

    1980-04-01

    Tissue-air ratio (TAR) and scatter-air ratio (SAR) are very important concepts in radiation dosimetry. In absence of any analytical relation for computation of these quantities a number of empirical equations have been fitted to experimentally measured data. This paper describes the derivation of analytical formulae from first principles. The resultant equations are very simple and can even be evaluated with the help of a slide rule. The computed values of TAR and SAR agree within 1% with the experimental data of Gupta and Cunningham (1966). PMID:7368231

  9. Response of lymphoid organs to low dose rate Cf-252, Cs-137 and acute Co-60

    SciTech Connect

    Feola, J.; Maruyama, Y.; Magura, C.; Hwang, H.N.

    1986-01-01

    RBE of low dose rate (LDR) /sup 252/Cf radiation was studied for thymus using weight loss compared to unirradiated controls. These were compared against LDR /sup 137/Cs and acute /sup 60/Co effects. For thymus, biexponential dose response curves were noted for acute /sup 60/Co and LDR /sup 137/Cs irradiations. No dose rate effect was noted with /sup 137/Cs. D/sub 37/ for the first component D/sub 1/ was 109 cGy and for the second D/sub 2/ was 624 cGy for /sup 60/Co. Relative biological effectiveness (RBE) is a complex endpoint and was different for the low dose (sensitive) and high dose (resistant) responses and for /sup 252/Cf. RBE/sub n/ of the sensitive portion was 1.7 and for overall was 4.0. Spleen response was also determined for the 3 radiations. Biexponential dose-response curves were also observed for resting spleen to acute /sup 60/Co and LDR /sup 137/Cs radiation. D/sub 1/ = 285 cGy and D/sub 2/ = 1538 cGy for acute /sup 60/Co; D/sub 1/ = 205 cGy for /sup 137/Cs and indicated a dose rate effect = 1.04 for /sup 137/Cs. The LDR /sup 137/Cs was 1.3x more effective than acute /sup 60/Co for the sensitive response; it was 1.9 x greater for the resistant response. However, the response to /sup 252/Cf vs. /sup 137/Cs for the spleen indicated that there was a greater sensitivity to dose rate than to LET. RBE/sub n/ for /sup 252/Cf vs. /sup 137/Cs was 1.0. Stimulation of spleen growth after injection of Corynebacterium parvum allowed study of radiation effects of proliferating spleen cells at day 10. Acute /sup 60/Co and LDR /sup 137/Cs ..gamma..-rays had reduced effects compared to LDR /sup 252/Cf radiation and RBE was 4.0 vs. LDR /sup 137/Cs. RBE in lymphoid organs thus depended on organ, on assay and on resting/proliferating status.

  10. Removal of CO-60 from aqueous solutions by alfalfa bio-sorbent

    SciTech Connect

    Omar, H.A.; Geleel, M. Abdel; Tawfik, A.A.

    2007-07-01

    Available in abstract form only. Full text of publication follows: A need to develop environmentally friendly technologies to retrieve precious metals has arisen due to the current mining methods which involve the use of harsh chemicals that endanger the community's health. Alfalfa biomass has a substantial ability to bind metal from aqueous solution. Removal of cobalt-60 from a solution was investigated to evaluate cation exchange capacity of alfalfa. The effect of solution pH, shaking time, mass of adsorbent, initial metal concentration and thermodynamics parameters were studied. The optimal pH range for cobalt removal was 7 and maximum percentage removal was 98%. Studies show that the adsorption decreases with increase the concentration. Adsorption isotherms were employed to describe the metal uptake; Freundlich and Langmuir types were found to fit the experimental data. Thermodynamics parameters, {delta}G{sup 0}, {delta}H{sup 0} and {delta}S{sup 0} have also been calculated for the system. (authors)

  11. Evaluation of silicon dosimetry parameters in Co-60 gamma irradiation facilities

    NASA Astrophysics Data System (ADS)

    Ferreira, Danilo Cardenuto; Bueno, Carmen Cecília

    2011-08-01

    This work presents the preliminary results of a dosimeter based on SFH00206 (Siemens) diode for gamma radiation dosimetry from 1 Gy up to 100 Gy. The diode operated in the photovoltaic mode and the current signals as a function of the exposure time were stable and linearly dependent on the dose rate with a sensitivity of 9.43 nA.Gy-1.min. The dosimetric response of the diode, characterized by the generated charge versus the absorbed dose, is linear within the dose range investigated.

  12. Measurement of dose given by Co-60 in radiotherapy with TLD-500

    NASA Astrophysics Data System (ADS)

    Tanır, Güneş; Cengiz, Ferhat; Hicabi Bölükdemir, M.

    2012-04-01

    The uses of dosimeters based on optically stimulated luminescence technique have become widespread in clinical applications. In the present study, the dose values given by Cobalt-60 radiotherapy machine were measured with optically stimulated luminescence (OSL) technique using TLD-500 and compared with those of commonly used ionization chamber dosimeter system. The percentage depth dose (DD%) values and graphs were formed. OSL system with TLD-500 can be reliably used as medical and personal dosimeter.

  13. Conditioning and Repackaging of Spent Radioactive Cs-137 and Co-60 Sealed Sources in Egypt - 13490

    SciTech Connect

    Hasan, M.A.; Selim, Y.T.; El-Zakla, T.

    2013-07-01

    Radioactive Sealed sources (RSSs) are widely use all over the world in medicine, agriculture, industry, research, etc. The accidental misuse and exposure to RSSs has caused significant environmental contamination, serious injuries and many deaths. The high specific activity of the materials in many RSSs means that the spread of as little as microgram quantities can generate significant risk to human health and inhibit the use of buildings and land. Conditioning of such sources is a must to protect humans and environment from the hazard of ionizing radiation and contamination. Conditioning is also increase the security of these sources by decreasing the probability of stolen and/or use in terrorist attacks. According to the law No.7/2010, Egyptian atomic energy authority represented in the hot laboratories and waste management center (centralized waste facility, HLWMC) has the responsibility of collecting, conditioning, storing and management of all types of radioactive waste from all Egyptian territory including spent radioactive sealed sources (SRSSs). This paper explains the conditioning procedures for two of the most common SRSSs, Cs{sup 137} and Co{sup 60} sources which make up more than 90% of the total spent radioactive sealed sources stored in our centralized waste facility as one of the major activities of hot laboratories and waste management center. Conditioning has to meet three main objectives, be acceptable for storage, enable their safe transport, and comply with disposal requirements. (authors)

  14. Estudio muestra importancia de conversaciones tempranas sobre el cuidado en etapa final de la vida

    Cancer.gov

    Artículo sobre la importancia de hablar en forma temprana sobre el cuidado paliativo para asegurar que la atención prestada en la etapa final de la vida sea más acorde con las preferencias de los pacientes.

  15. Dose rate effects on array CCDs exposed by Co-60 γ rays induce saturation output degradation and annealing tests

    SciTech Connect

    Wang, Zujun Chen, Wei; He, Baoping; Yao, Zhibin; Xiao, Zhigang; Sheng, Jiangkun; Liu, Minbo

    2015-10-15

    The experimental tests of dose rate and annealing effects on array charge-coupled devices (CCDs) are presented. The saturation output voltage (V{sub S}) versus the total dose at the dose rates of 0.01, 0.1, 1.0, 10.0 and 50 rad(Si)/s are compared. Annealing tests are performed to eliminate the time-dependent effects. The V{sub S} degradation levels depend on the dose rates. The V{sub S} degradation mechanism induced by dose rate and annealing effects is analyzed. The V{sub S} at 20 krad(Si) with the dose rate of 0.03 rad(Si)/s are supplemented to assure the degradation curves between the dose rates of 0.1 and 0.01 rad(Si)/s. The CCDs are divided into two groups, with one group biased and the other unbiased during {sup 60}Co γ radiation. The V{sub S} degradation levels of the biased CCDs during radiation are more severe than that of the unbiased CCDs.

  16. Air cavity effects on the radition dose to the larynx using Co-60, 6 MV, and 10 MV photon beams

    SciTech Connect

    Niroomand-Rad, A.; Harter, K.W.; Thobejane, S.; Bertrand, K.

    1994-07-30

    The purpose was to determine the perturbation effect in the surface layers of lesions located in the air-tumor tissues interface of larynx using {sup 60}Co, 6 MV, and 10 MV photon beams. Thermoluminescent dosimeters (TLDs) were embedded at 16 measurement locations in slab no. 8 of a humanoid phantom and exposed to two lateral-opposed beams using standard 7 {times} 7 cm fields. Similarly, radiographic and radiochromic films were placed between slabs no. 7 and no. 8 of the humanoid phantom and exposed to two lateral-opposed radiation beams. The dosimeters were irradiated with {sup 60}Co, 6 MV, and 10 MV photon beams. Computer tomography (CT) treatment planning without inhomogeneity correction was performed. At the tissue-air interface, the average measured percentage dose (% dose{sub m}) is about (108.7 {+-} 4.8%) with TLD data, (96.8 {+-} 2.5%) with radiographic film data, and (100.8 {+-} 4.9%) with radiochromic film data. Similarly, in the central part of the cavity, the % dose{sub m} is (98.4 {+-} 3.1)% with TLD data, (94.3 {+-} 3.3)% with radiographic film data, and (91.7 {+-} 5.0)% with radiochromic film data. Using the CT-based generated dose distribution (without inhomogeneity correction), the average calculated percentage dose (% dose{sub c}) is (98.7 {+-} 1.0%) at the tissue-air interface and 98% in the central part of the air cavity. For the beam energies studied, the variation from the % dose {sub m} at the tissue-air interface for a given dosimetry technique is relatively small and therefore should not be significant in clinical settings. The variation from the % dose{sub m} at the tissue-air interface is more significant for lower energies. This variation is about 4.3% for 10 MV photon beam, therefore, while institutional practice favors lower energy ({sup 60}Co to 6 MV) for node-negative glottic cancers, physical/dosimetric evidence offers no disadvantage to the use of higher energy photons. 10 refs., 7 figs., 2 tabs.

  17. Malignant melanoma of the eye: treatment of posterior uveal lesions by Co-60 plaque radiotherapy versus enucleation

    SciTech Connect

    Markoe, A.M.; Brady, L.W. Jr.; Shields, J.A.; Augsburger, J.J.; Micaily, B.; Damsker, J.I.; Day, J.L.; Gamel, J.W.

    1985-09-01

    Survival rates and visual acuity of 100 patients treated for posterior uveal malignant melanoma by cobalt-60 plaque radiotherapy were compared with 150 patients treated by enucleation for the same disease. Life-table comparisons of the entire group showed significant differences in survival rates, with plaque radiotherapy patients appearing to fare better. However, when patients with small or medium tumors were compared, only slight differences were seen, implying that criteria used to select patients for treatment may affect interpretation. The two groups were also compared using the Cox proportional hazards model, which predicts survival based on the impact of clinical variables. In this analysis, the survival rates of the plaque radiotherapy group were no worse than those of the enucleation group. The advantage of conservative therapy lies in the potential to preserve useful vision over a considerable time.

  18. BIOKINETICS OF SYSTEMICALLY DISTRIBUTED CO-60 IN THE RAT: AN EXPERIMENTAL MODEL USEFUL IN EVALUATING MEDICAL COUNTERMEASURES FOR INTERNAL CONTAMINATION

    PubMed Central

    Weber, Waylon; Doyle-Eisele, Melanie; Seilkop, Steven K.; Guilmette, Raymond

    2012-01-01

    LBERI, a member of the Medical Countermeasures to Radiologic Threats (MCART) consortium funded by NIAID, was tasked to develop biokinetic models for the distribution of radionuclide threats using the most likely routes of incorporation in both small and large animals. In the present paper, the biokinetics of systemically administered soluble cobalt-60 (60Co) have been examined. Male and female jugular-vein-catheterized (JVC) F344 rats received intravenous (IV) doses of 11.2 kBq of 60CoCl2. The distribution of the radiocobalt was followed for 28 d, with tissue sampling done at 1 and 4 h, and at 1, 2, 4, 8, 16, and 28 d. Urine and feces were collected daily. Tissues and excreta were analyzed by gamma pulse height analysis. Within 8d, 93% of the cobalt was eliminated from the body primarily though urine. The highest tissue burdens were found in liver, gastrointestinal (GI) tract, and muscle shortly after administration. These tissues cleared quickly so that by the conclusion of the 28-d study, less than 3% of the recovered dose remained in the body. The results are comparable to published literature values for tissue content of 60Co and for excretion patterns up to 30 d after injection. These results will provide the data needed to construct a biokinetic model for the unperturbed biokinetics of 60Co in rats, which will subsequently be used to evaluate the impact of administered decorporating agents on organ radiation doses. The animal model described in this paper is representative of that used for other routes of radionuclide administration such as inhalation, ingestion and wound contamination that have been studied at LBERI in support of the MCART and NIAID programs. PMID:22929473

  19. Radiation inactivation of Paenibacillus larvae and sterilization of American Foul Brood (AFB) infected hives using Co-60 gamma rays.

    PubMed

    De Guzman, Zenaida M; Cervancia, Cleofas R; Dimasuay, Kris Genelyn B; Tolentino, Mitos M; Abrera, Gina B; Cobar, Ma Lucia C; Fajardo, Alejandro C; Sabino, Noel G; Manila-Fajardo, Analinda C; Feliciano, Chitho P

    2011-10-01

    The effectiveness of gamma radiation in inactivating the Philippine isolate of Paenibacillus larvae was investigated. Spores of P. larvae were irradiated at incremental doses (0.1, 0.2, 0.4, 0.8 and 1.6 kGy) of gamma radiation emitted by a ⁶⁰Co source. Surviving spores were counted and used to estimate the decimal reduction (D₁₀) value. A dose of 0.2 kGy was sufficient to inactivate 90% of the total recoverable spores from an initial count of 10⁵- 9 × 10³ spores per glass plate. The sterilizing effect of high doses of gamma radiation on the spores of P. larvae in infected hives was determined. In this study, a minimum dose (D(min)) of 15 kGy was tested. Beehives with sub-clinical infections of AFB were irradiated and examined for sterility. All the materials were found to be free of P. larvae indicating its susceptibility to γ-rays. After irradiation, there were no visible changes in the physical appearance of the hives' body, wax and frames. Thus, a dose of 15 kGy is effective enough for sterilization of AFB-infected materials. PMID:21683605

  20. Informe Anual a la Nación sobre el Estado del Cáncer con una sección especial sobre la prevalencia d

    Cancer.gov

    El Informe Anual a la Nación sobre el Estado del Cáncer (1975 a 2010), mostró un descenso más acelerado que en años anteriores de los índices de mortalidad por cáncer de pulmón. También contiene una sección especial que destaca los efectos significativos

  1. Some Research-Based Issues and Recommendations Expressed at the Seminario Internacional Sobre la Educacion Bilingue.

    ERIC Educational Resources Information Center

    Bernal, Ernesto M.

    The first Seminario Internacional Sobre la Educacion Bilingue (International Seminar on Bilingual Education), under the aegis of the National Association for Bilingual Education and the Mexican secretary for public education, brought together professionals from Canada, the United States, and Mexico in Oaxtepec, Mexico in November 1986 to share…

  2. Informe del NCI y los CDC sobre el tabaco sin humo

    Cancer.gov

    El primer informe sobre el consumo mundial del tabaco sin humo y sus consecuencias en la salud pública reveló que más de 300 millones de personas en al menos 70 países usan estos productos dañinos.

  3. Discussions about the Nature of Science in a Course on the History of Astronomy. (Spanish Title: Discusiones sobre la Naturaleza de la Ciencia en un Curso sobre Historia de la Astronomía.) Discussões sobre a Natureza da Ciência em um Curso sobre a História da Astronomia

    NASA Astrophysics Data System (ADS)

    Pires de Andrade, Victória Flório; L'Astorina, Bruno

    2010-07-01

    There are an increasing number of researches in science education that affirm the importance of discussions on the "nature of science" in basic education level as well as in teacher training. The history of science applied to education is a way to contextualize epistemological discussions, allowing both the understanding of scientific content and learning about science concepts. We present some reasonably consensual definitions on the nature of science that have been widely discussed by the academic community. We show also some episodes in the history of astronomy which can lead to discussions involving some aspects of the nature of science, and how they can do it. Hay un número creciente de investigaciones en la enseñanza de las ciencias que afirman la importancia de debates sobre la "naturaleza de la ciencia" en la educación básica y formación del profesorado. La historia de la ciencia aplicada a la educación es una manera de contextualizar los debates de la epistemología, lo que permite tanto la comprensión de los contenidos científicos como el aprendizaje de conceptos científicos. En esto trabajo, presentamos algunas definiciones bastante consensuales sobre la naturaleza de la ciencia que han sido ampliamente discutidas por la comunidad académica y mostramos cómo algunos episodios en la historia de la astronomía pueden llevar a discusiones sobre algunos aspectos de la naturaleza de la ciencia. Há um número crescente de pesquisas na área de ensino de ciências que afirmam a importância de discussões sobre a "natureza da ciência" na educação básica e na formação de professores. A história da ciência aplicada ao ensino é uma maneira de contextualizar discussões epistemológicas, permitindo tanto a compreensão de conteúdos científicos quanto o aprendizado de noções sobre as ciências. Neste trabalho apresentamos algumas definições razoavelmente consensuais sobre a natureza da ciência que foram amplamente discutidas pela

  4. Informe Anual a la Nación sobre el Estado del Cáncer, 1975 a 2012

    Cancer.gov

    El Informe Anual a la Nación sobre el Estado del Cáncer, 1975 a 2012, es una actualización de los índices de casos nuevos, muertes y tendencias de los cánceres más comunes en los Estados Unidos.

  5. Conversation with Lara about the Earth and Land. (Spanish Title: Conversando con Lara sobre la Tierra y la Teirra.) Conversando com Lara sobre a Terra e a Terra

    NASA Astrophysics Data System (ADS)

    da Conceição Barbosa-Lima, Maria

    2010-12-01

    The present article is the analysis of a conversation between the author and Lara, a four-yearold- girl, enrolled in nursery school, while she makes a drawing of the Earth. It took place outside school environment and without any other person around to avoid interference during the interview. According to Ferreira & Silva (2004), a researcher can only comprehend a child's drawing, or form, by listening to him/her while he/she is creating it. Lara presented the traditional flat drawing, picturing the sky parallel to the ground, as reported by Nardi & Carvalho (1996). However, when asked to draw the World - term used by Butterworth et al. (2002), in order to avoid unnecessary confusion - she represented it by a circle, with herself on the surface. Her drawings led to the conclusion that such girl does not know yet the World in which she lives is the Earth, and probably because of that, within her age and consequent maturity, she accurately differentiates the concepts of land and Earth. El presente artículo analiza una entrevista libre, mientras una niña de 4 años y 4 meses, matriculada en el pregrado, dibuja la Tierra. Esta entrevista se realizó fuera del ambiente escolar y sin otra persona alrededor que pudiera interferir. De acuerdo con Ferreira Silva (2004), para quien investiga es posible conocer realmente lo que un niño o una niña pone en el papel a través de grafismos y/o dibujos si se lo escucha durante el proceso de creación de la escritura con imágenes. La niña, en este caso, representa la Tierra con el tradicional dibujo plano y el "cielo" paralelo al suelo, conforme analizaron Nardi & Carvalho (1996). Pero, cuando se Le solicita dibujar el "Mundo" - palabra empleada en un trabajo de Butterworth et al. (2002), con intención de no provocar "confusiones" innecesarias a sus sujetos de investigación- lo representa de forma circular, poniéndose sobre su superficie. Sus dibujos llevan a concluir que esta niña aún no tiene conocimiento que el mundo

  6. El Informe a la Nación sobre el Estado del Cáncer, 1975-2012

    Cancer.gov

    El Informe a la Nación sobre el Estado del Cáncer (1975-2012) indica que continuó la baja de tasas de mortalidad de todos los cánceres juntos, así como de la mayoría de los cánceres en hombres y mujeres de todos los grupos raciales y étnicos principales.

  7. O que bilíngues bimodais têm a nos dizer sobre desenvolvimento bilíngue?

    PubMed Central

    de Quadros, Ronice Müller; Lillo-Martin, Diane; Pichler, Deborah Chen

    2013-01-01

    O objetivo deste trabalho é apresentar o que as pesquisas que estamos desenvolvendo com crianças ouvintes, filhas de pais surdos, adquirindo Língua Brasileira de Sinais (Libras) e Português e Língua de Sinais Americana (ASL) e Inglês (Lillo-Martin et al. 2010) têm a nos dizer sobre desenvolvimento bilíngue. Os dados deste estudo fazem parte de um banco de dados de interações espontâneas coletadas longitudinalmente, alternando contextos de aquisição da Libras e do português como língua alvo, no Brasil e dados coletados longitudinalmente. nos mesmos contextos, de crianças adquirindo ASL e inglês1. Além disso, há também dados do estudo experimental com testes aplicados nos dois pares de línguas que se agregam ao presente estudo. Uma visão geral dos estudos desenvolvidos sobre a aquisição bilíngue bimodal por crianças ouvintes, filhas de pais surdos, será apresentada e, então, serão expostos alguns aspectos linguísticos deste tipo de aquisição, considerando as discussões sobre aquisição bilíngue a partir da pesquisa realizada. PMID:24431480

  8. University Students' Conceptions about the Moon Phases. (Spanish Title: Concepciones de Estudiantes Universitários sobre Las Fases de la Luna.) Concepções de Estudantes Universitários sobre as Fases da Lua

    NASA Astrophysics Data System (ADS)

    de Fátima Oliveira Saraiva, Maria; da Silveira, Fernando Lang; Steffani, Maria Helena

    2011-07-01

    In this article we describe the development of a multiple choice test about lunar phases and analyze the results of its application to ten groups of Physics students at the UFRGS. During the improvement of the test, we noticed that the percentage of right answers about some concepts increased significantly when associated with the reformulation of the question, emphasizing the importance of being careful to avoid incorrect answers generated by unclear questions, and not by ignorance on the matter. We confirm the results of other studies that show that students have great difficulty to relate the Moon's phase with its position in the sky at given time. On the other hand, our results suggest that, in general, students of Physics understand the phenomenon of lunar phases better than the average of university students. En estese artículo se describe la elaboración de una prueba de opción múltiple sobre las fases de la Luna y se analizan los resultados de su aplicación en diez grupos de estudiantes de Física de UFRGS. Durante el mejoramiento de la prueba observamos que el porcentaje de aciertos creció considerablemente cuando considerada una nueva redacción de la pregunta, destacando el cuidado que se debe tomar a fin de evitar respuestas incorrectas generadas por preguntas poco claras y no a causa de la ignorancia de los estudiantes sobre el tema. Confirmamos los resultados de otros estudios que las mayores dificultades de los alumnos sobre el tema fases de la Luna están en relacionar la fase de la Luna con su posición en el cielo en determinado momento. Por otra parte, nuestros resultados sugieren que, en general, los estudiantes de la Física comprenden mejor el fenómeno de las fases lunares que el promedio de los estudiantes universitarios. Neste artigo descrevemos a elaboração de um teste de múltipla escolha sobre as fases da Lua e analisamos os resultados de sua aplicação em dez grupos de estudantes de Física da UFRGS. Durante o aprimoramento do

  9. Sobre a largura da última superfície de espalhamento

    NASA Astrophysics Data System (ADS)

    Nobre, M. A. S.; Pires, N.; Lima, J. A. S.

    2003-08-01

    De acordo com o modelo do "Big-Bang", no universo primordial a matéria estava em equilíbrio térmico com a radiação. Com a expansão a temperatura da radiação cai. Quando a temperatura chega em torno dos 4.000K, os espalhamentos diminuem, começando a recombinação dos prótons e elétrons em Hidrogênio neutro (era conhecida como da recombinação). Ao final da recombinação, os fótons se propagam livremente sofrendo, em princípio, somente os efeitos do "redshift" cosmológico. Esses fótons nos alcançam hoje como a radiação cósmica de fundo (RCF), e parecem vir de uma superfície esférica ao nosso redor, tal que o raio dela é a distância que ele viajou desde seu último espalhamento na época da recombinação. Naturalmente, esse processo não ocorreu abruptamente, implicando na existência de uma largura no espaço dos "redshifts" que deve depender do modelo cosmológico específico e dos processos físicos considerados. Neste trabalho analisamos os efeitos de diferentes modelos - a saber, aqueles com decaimento do vácuo L(t), criação de matéria, quintessência e gás de Chaplygin - sobre a última superfície de espalhamento da RCF, em particular sua largura e a função visibilidade, que determina a probabilidade de um fóton ter tido seu último espalhamento num "redshift" z. No caso particular dos modelos com decaimento do vácuo, existe uma forte dependência da função visibilidade com L(t). Tais efeitos poderão ser testados através da análise dos resultados de experimentos mais precisos que estão atualmente em andamento, como por exemplo, o WMAP.

  10. Tendências de teses e dissertações sobre ensino de astronomia no Brasil

    NASA Astrophysics Data System (ADS)

    Bretones, P. S.; Megid Neto, J.

    2003-08-01

    Neste trabalho são apresentados os resultados de uma pesquisa do tipo estado da arte sobre teses e dissertações defendidas no Brasil e relativas ao ensino de Astronomia. Teve por objetivo identificar essa produção e conhecer as principais tendências da pesquisa nesse campo. O procedimento inicial consistiu de um levantamento bibliográfico junto ao Centro de Documentação em Ensino de Ciências (CEDOC) da Faculdade de Educação da UNICAMP e ao Banco de Teses da CAPES disponível na Internet. Foram localizadas 13 dissertações de mestrado e 3 teses de doutorado, as quais foram estudadas em função dos seguintes aspectos: instituição, ano de defesa, nível escolar abrangido no estudo, foco temático do estudo e gênero de trabalho acadêmico. Deste conjunto de pesquisas, 13 (81,3%) delas foram defendidas a partir da segunda metade dos anos 90, indicando uma preocupação mais recente com temas relativos ao ensino de Astronomia no conjunto da produção acadêmica em programas de pós-graduação no Brasil. Verificou-se que 43,7% dos trabalhos foram produzidas na USP e 18,8% na UNICAMP. Quanto ao nível escolar abrangido nos estudos, predominaram os estudos direcionados ao Ensino Fundamental de 5a a 8a séries (62,5%). No que diz respeito ao foco temático das pesquisas, as principais tendências voltaram-se: 56,3% para Conteúdo e Método; 43,8% para Concepções do Professor; 37,5% para Currículo e Programas; 37,5% para Recursos Didáticos. Quanto ao gênero de trabalho acadêmico, verificou-se que 43,8% são de Pesquisa Experimental e 31,3% de Pesquisa de Análise de Conteúdo. Estudos de revisão bibliográfica como este visam colaborar com a divulgação ampla da produção acadêmica em determinada área, traçando algumas de suas tendências. Ao mesmo tempo possibilita, a partir de investigações decorrentes, apontar as suas contribuições para o ensino e sinalizar com necessidades a serem supridas por futuras pesquisas.

  11. Reflexión bioética sobre el uso de organismos genéticamente modificados

    PubMed Central

    Yunta, Eduardo Rodríguez

    2011-01-01

    El presente artículo reflexiona desde los 4 principios de la bioética el uso comercial de organismos genéticamente modificados. Se cuestiona fundamentalmente la falta de transferencia de tecnología entre el mundo desarrollado y en desarrollo y el que el presente sistema de patentamiento de organismos vivos modificados fomenta intereses comerciales y no da debida importancia al desarrollo sostenible de la agricultura y ganadería en los países en desarrollo, donde más se necesita. Se reflexiona sobre la importancia que tiene evaluar los riesgos antes de introducirse en el mercado organismos genéticamente modificados y la necesidad de regulación en los países. PMID:21927675

  12. Educación sobre sexualidad y prevención del VIH: un diagnóstico para América Latina y el Caribe

    PubMed Central

    DeMaria, Lisa M.; Galárraga, Omar; Campero, Lourdes; Walker, Dilys M.

    2016-01-01

    RESUMEN Objetivo Mostrar, a través de un diagnóstico en América Latina y el Caribe, el panorama legislativo y curricular sobre sexualidad y prevención contra el virus de inmunodeficiencia humana (VIH) en el ámbito escolar, contrastándolo con los comportamientos sexuales reportados en encuestas demográficas y de salud. Métodos En mayo de 2008 se realizó, con el apoyo del Fondo de Población de las Naciones Unidas (UNFPA), una encuesta a informantes clave en 34 países de la Región. El cuestionario autoaplicado solicitó información sustantiva de agentes de las diferentes partes interesadas, como ministerios de educación y de salud, sobre los programas de prevención contra el VIH/Sida que se están aplicando en las escuelas. Resultados Respondieron a la encuesta 27 países que representan 95,5% de la población objetivo (6 a 18 años de edad). La mayoría de los países informó tener al menos un libro de texto o un capítulo específico para enseñar los temas de educación sobre sexualidad y prevención del VIH. En la escuela secundaria se cubren la mayor parte de los temas pertinentes relevantes para la educación sobre sexualidad, pero no todos. Por ejemplo, el problema de la discriminación por orientación o preferencia sexual no se incluye en los programas escolares. Conclusiones El material educativo sobre sexualidad debe ser revisado y actualizado periódicamente de modo que refleje los avances en los temas y en la forma de tratar los contenidos. En cada país el currículo debe abordar el tema del respeto a la diversidad sobre orientación, preferencia e identidad sexuales, y en particular el manejo apropiado de la educación para prevenir infecciones de transmisión sexual (ITS) en hombres que tienen sexo con hombres. Los esfuerzos de evaluación de la efectividad de los programas deben contemplar desenlaces tales como marcadores biológicos (incidencia y prevalencia de ITS y embarazo) y no únicamente indicadores de conocimiento y

  13. Tendências De Teses e Dissertações Sobre Educação em Astronomia No Brasil

    NASA Astrophysics Data System (ADS)

    Bretones, Paulo Sergio; Megid Neto, Jorge

    2005-07-01

    Apresentam-se os resultados de uma pesquisa do tipo estado da arte sobre teses e dissertações defendidas no Brasil e relativas ao ensino de Astronomia, com objetivo de identificar essa produção e conhecer as principais tendências da pesquisa nesse campo. Foram localizadas 13 dissertações de mestrado e 3 teses de doutorado, as quais foram estudadas em função dos seguintes aspectos: isntituição, ano de defesa, nível escolar abrangido no estudo, foco temático do estudo e gênero de trabalho acadêmico. Pretende-se assim colaborar com a divulgação ampla da produção acadêmica na área. Ao mesmo tempo o estudo possibilita, a partir de investigações decorrentes, apontar as contribuições dessa produção para o ensino e sinalizar com necessidades a serem supridas por futuras pesquisas.

  14. Three-dimensional dose-rate distribution of X-ray beams of linac neptun 10p and gamma-rays from Co-60 gammatron 80S for rectangular fields.

    PubMed

    Lobodziec, W; Lambrinow, N; Stala, T; Kośniewski, W

    1981-05-01

    A method of calculation of the three-dimensional dose-rate distribution for X-rays of Linac Neptun 10p and gamma-rays of Gamma-tron 80S is presented. The experimental results show that the profiles function defined as the relative dose-rate across the radiation beam is useful for this purpose, and it is sufficient to determine the profile function only at one depth and for one field size. The results of measurements are presented on the graphs. PMID:7245280

  15. Sobre a atividade pós-periélica do cometa de órbita parabólica Yanaka (1988r)

    NASA Astrophysics Data System (ADS)

    de Almeida, A. A.; Sanzovo, G. C.; Boczko, R.

    2003-08-01

    Greenberg, Singh & de Almeida (ApJ, 414: L45-48, 1993) mostraram que a deficiência nas abundâncias observadas de C2 e CN no Cometa Yanaka (1988r) pode ser explicada em termos das propriedades dos seus componentes refratários orgânicos, além do fato que trata-se de um cometa dinamicamente novo, observado através de abertura de fenda pequena projetada muito próximo do núcleo. Neste trabalho, complementamos o estudo sobre a atividade deste cometa de órbita parabólica, através da determinação da lei de potência que exprime sua taxa de produção de H2O (o principal indicador de atividade) na fase pós-periélica, determinamos o raio nuclear efetivo mínimo com sua fração de área ativa e analisamos a emissão de partículas de poeira observadas no contínuo em 625,0 nm.

  16. Cambios históricos en el aporte terrígeno de la cuenca del Río de la Plata sobre la plataforma interna Uruguaya

    NASA Astrophysics Data System (ADS)

    Marrero, Analía; Tudurí, Adriana; Pérez, Laura; Cuña, Caroline; Muniz, Pablo; Lopes Figueira, Rubens; Michaelovitch de Mahiques, Michel; Alves de Lima Ferreira, Paulo; Pittauerová, Daniela; Hanebuth, Till; García Rodríguez, Felipe

    2014-12-01

    B 13813-4. También se determinó una mayor acumulación de sedimentos a través del tiempo en el cinturón de barro del Río de la Plata (plataforma continental adyacente), comparado con aquel registrado en la Barra del Indio (límite entre zona intermedia y externa del estuario). Estas diferencias podrían estar relacionadas con la influencia del Río de la Plata, el cual genera un ambiente altamente dinámico sobre la Barra del Indio y un ambiente más estable sobre el cinturón de barro en la plataforma continental.

  17. Desarrollo de la Escala sobre el Estigma Relacionado con el VIH/SIDA para Profesionales de la Salud mediante el uso de métodos mixtos123

    PubMed Central

    Varas-Díaz, Nelson; Neilands, Torsten B.; Guilamo-Ramos, Vincent; Cintrón Bou, Francheska N.

    2009-01-01

    El estigma relacionado con el VIH/SIDA continúa siendo un obstáculo para la prevención primaria y secundaria del VIH. Las consecuencias para las personas que viven con la enfermedad han sido muy documentadas y continúan siendo una gran preocupación para las personas que proveen servicios de salud y para aquellas que investigan el tema. Estas consecuencias son preocupantes cuando el estigma emana de profesionales de la salud porque se puede limitar el acceso a los servicios. Uno de los principales obstáculos para la investigación del estigma relacionado con el VIH en Puerto Rico es la falta de instrumentos cuantitativos para evaluar las manifestaciones del estigma entre profesionales de la salud. El objetivo principal de este estudio fue desarrollar y probar las propiedades psicométricas de una escala sobre el estigma relacionado con el VIH/SIDA culturalmente apropiada para personas que proveen servicios de salud puertorriqueñas y desarrollar una versión corta de la escala que pudiera usarse en escenarios clínicos con tiempo limitado. El instrumento desarrollado estuvo basado en evidencia cualitativa recopilada entre profesionales y estudiantes de profesiones de la salud puertorriqueños/as (n=80) y administrado a una muestra de 421 profesionales de la salud en adiestramiento. La escala contenía 12 dimensiones del estigma relacionado con el VIH/SIDA. El análisis cuantitativo corroboró 11 de ellas, teniendo como resultado un instrumento con validez y confiabilidad satisfactoria. Estas dimensiones, a su vez, fueron subcomponentes de un factor de estigma general superior. PMID:20333258

  18. Investigaccion-accion en la sala de clases sobre las creencias de la cultura de la ciencia de un grupo de estudiantes universitarios y su relacion reciproca con el aprendizaje de las ciencias biologicas

    NASA Astrophysics Data System (ADS)

    Cordova-Santiago, Lizzette Astrid

    La investigacion---accion que se llevo a cabo en la sala de clases tenia como punto de partida las creencias de la cultura de la ciencia de un grupo de estudiantes universitarios para luego examinar sus implicaciones en el proceso de aprendizaje de las Ciencias Biologicas. ¿Que se supone que hagan las creencias en relacion con el aprendizaje? ¿En que consiste incorporar este aspecto a la practica educativa universitaria? Utilizando el modelo de Kemmis y McTaggart (1987) la investigacion-accion se planteo como un proceso dinamico en cuatro momentos en espiral constituidos por la planificacion, la accion, la observacion y la reflexion. Cada una de las fases tuvo una intencion retrospectiva y prospectiva formando una espiral de autorreflexion del conocimiento y la accion. Se llevaron a cabo audio grabaciones en clases y analisis de documentos. Ademas, la profesora-investigadora hizo un portafolio para reflexionar sobre las creencias de la cultura de la ciencia que tienen los estudiantes y las creencias del aprendizaje que tiene la profesora y sobre como la comprension de estos elementos ayudo a mejorar su practica educativa a traves del tiempo. Los resultados obtenidos apuntan a que las creencias de la cultura de la ciencia que tiene el grupo de estudiantes son diversas. Ellos si creen que la ciencia tiene una cultura la cual describieron como: complicada y desconocida que evoluciona constantemente, que es un conjunto de metodos, que es altamente tecnologica, que resuelve problemas de salud, ayuda a interpretar la realidad del mundo que los rodea y su origen y que existen unas intersecciones entre la ciencia y el poder. Sobre las creencias del proceso de aprendizaje de la profesora-investigadora, estas senalan que el modelaje de actores, la vision de la academia que tiene ella asi como la participacion y negociacion entre todos los involucrados en el proceso educativo, son factores que inciden en el proceso de aprendizaje.

  19. La utilizacion de los mapas conceptuales en la ensenanza de biologia y su efecto sobre el dominio del proceso de fotosintesis en los estudiantes universitarios

    NASA Astrophysics Data System (ADS)

    Gonzalez Rivera, Maria M.

    Se investigo el efecto de los mapas conceptuales sobre el dominio del proceso de fotosintesis en estudiantes universitarios. La investigacion utilizo dos estrategias: mapas conceptuales individuales y mapas conceptuales colaborativos, con el fin de investigar si existen diferencias significativas en el dominio del proceso de fotosintesis. El analisis de los datos incluyo aspectos cualitativos y cuantitativos. Se desprende del estudio que el 80% de los estudiantes describen la utilizacion de los mapas conceptuales como una experiencia beneficiosa. El 70% de los estudiantes expreso que los mapas conceptuales son utiles en el aprendizaje del proceso de fotosintesis y el 61% indico que facilitan la comprension de los conceptos. Los hallazgos mas importantes del analisis cuantitativo indican que los estudiantes que utilizaron los mapas conceptuales mejoraron significativamente su desempeno en la posprueba global. Se utilizo la prueba Mann-Whitney para investigar si existian diferencias significativas en la posprueba y preprueba global, el valor de W = 1945.0, para un valor p de 0.00, lo cual establece diferencias significativas. Para determinar si existian diferencias significativas entre la posprueba y preprueba del grupo individual, se realizo la prueba nuevamente. El valor de W correspondio a 490.5, que es significativo, con un valor p de 0.00. Se concluye que existen diferencias significativas entre la ejecucion de la posprueba y preprueba del grupo individual. Los datos proveen suficiente evidencia para sostener que los estudiantes que utilizaron la estrategia de mapas conceptuales individuales mejoraron el dominio del proceso de fotosintesis significativamente. Se realizo nuevamente la prueba para los resultados de posprueba y preprueba del grupo colaborativo. El valor de W correspondio a 446 con un valor p de 0.00. Se concluyo que existen diferencias significativas entre la ejecucion de la posprueba y preprueba del grupo colaborativo. Finalmente, se efectuo una

  20. Distinción Empírica Entre Engagement y Trabajolismo en Enfermeras Hospitalarias de Japón: Efecto Sobre la Calidad del Sueño y el Desempeño Laboral

    PubMed Central

    Kubota, Kazumi; Shimazu, Akihito; Kawakami, Norito; Takahashi, Masaya; Nakata, Akinori; Schaufeli, Wilmar B.

    2016-01-01

    Objetivo El objetivo de este estudio es demostrar la distinción entre engagement y trabajolismo, estudiando su relación con la calidad del sueño y el desempeño laboral. Método Un total de 447 enfermeras de 3 hospitales de Japón fueron entrevistadas mediante un cuestionario autoadministrado que incluía la escala Utrecht (UWES, Utrecht Work Engagement Scale), la Escala de Adicción al Trabajo Holandesa (DUWAS, Dutch Workaholism Scale), preguntas sobre la calidad del sueño (7 ítems) con respecto a (1) dificultad para conciliar el sueño, (2) dificultad para mantener el sueño, (3) despertar temprano por la mañana, (4) dormirse o tomar siestas durante el día, (5) somnolencia diurna excesiva en el trabajo, (6) dificultad para despertarse por la mañana, y (7) despertar cansado en la mañana, y el Cuestionario sobre Salud y Desempeño (CSD) de la Organización Mundial de la Salud. Resultados Los modelos de ecuaciones estructurales demostraron que el engagement se relaciona positivamente con la calidad del sueño y el rendimiento laboral, mientras que el trabajolismo tiene una relación negativa con la calidad del sueño y el desempeño laboral. Conclusión Los resultados indican que el engagement y el trabajolismo son conceptualmente diferentes. El primero tiene una connotación positiva, mientras que el segundo se asocia de manera negativa al bienestar (buena calidad del sueño y buen rendimiento en el trabajo). PMID:26752805

  1. Estudio de la estructura logica utilizada en la ensenanza y el aprendizaje de los conceptos sobre el comportamiento de gases en el curso introductorio de quimica a nivel universitario

    NASA Astrophysics Data System (ADS)

    Costa Diaz, Agnes

    El estudio que se presenta es de caracter cualitativo, un estudio multicasos donde se estudia la estructura logica utilizada por cuatro (4) profesores universitarios que ensenan el curso introductorio de quimica, en la planificacion, presentacion y evaluacion del tema sobre el comportamiento de los gases. Se utilizaron varias fuentes de informacion como: cuestionarios de profesores y estudiantes, entrevistas, grabaciones videomagnetofonicas, materiales didacticos y una prueba conceptual, entre otros. La informacion recopilada fue analizada de acuerdo al orden logico del contenido presentado, el estilo de ensenanza del profesor, las tecnicas y estrategias utilizadas para el desarrollo de destrezas de pensamiento, el ambiente fisico en el salon de clase y los instrumentos de evaluacion y avaluo. El estudio demuestra que lo que los profesores piensan y planifican para hacer sus presentaciones no necesariamente es lo que ocurre en el salon de clases. El desarrollo de destrezas de pensamiento, que constituye una prioridad de los profesores, no se elaboran efectivamente. El uso de las estrategias de resolucion de problemas numericos predomino. La participacion del estudiante en el salon de clases fue limitada y no se logro demostrar el desarrollo de las destrezas de pensamiento deseadas. Aunque los profesores tienen su propio estilo de ensenanza, el orden logico del contenido presentado en clase fue el mismo o siguio muy de cerca el orden establecido por el libro de texto. Los profesores utilizaron preferentemente la tiza y la pizarra para sus presentaciones y la dinamica en el salon de clases fue esencialmente tradicional. Los profesores hicieron su presentacion y los estudiantes copiaron pasivamente la informacion. Las evaluaciones de los estudiantes fueron esencialmente, pruebas escritas de seleccion multiple de acuerdo con el estilo en que se les enseno. El avaluo fue casi inexistente. La prueba conceptual administrada revela un aprendizaje pobre en los conceptos mas

  2. High School Student's Alternative Conceptions About the Phenomenon of the Formation of the Moon Phases. (Spanish Title: Concepciones Alternativas de Alumnos de Educación Media Sobre el Fenómeno de Formación de las Fases de La Luna.) Concepções Alternativas de Alunos do Ensino Médio Sobre o Fenômeno de Formação das Fases da Lua

    NASA Astrophysics Data System (ADS)

    Iachel, Gustavo; Langhi, Rodolfo; Fernandes Scalvi, Rosa Maria

    2008-07-01

    Forty students, at ages between 14 and 18 years old, from three schools in Bauru city, were questioned about their alternative conceptions concerning the phenomenon of formation of the Moon Phases. It was observed that some of the pupils confound the phenomenon of the formation of the Moon Phases with the phenomenon of the formation of the lunar eclipses, others are unaware of the reason of the phenomenon, they present incoherent alternative conceptions of the reality or incomplete conceptions. The results found here are aimed at the teachers of Elementary Education and can be used as a subsidy for future development of new pedagogical methods. Cuarenta estudiantes, con edad entre 14 y 18 años, pertenecientes a tres escuelas de la ciudad de Bauru, fueron cuestionados sobre sus concepciones alternativas acerca del fenómeno de la formación de las fases de la Luna. Fue observado que algunos alumnos confunden el fenómeno de formación de las fases de la Luna con el fenómeno de formación de los eclipses lunares, otros desconocen el motivo delfenómeno, presentan concepciones alternativas incoherentes con la realidad o bien presentan concepciones incompletas. Los resultados aquí encontrados son destinados a los profesores de la Enseñanza Básica y podrán ser usados como ayuda para el futuro desarrollo de nuevos métodos pedagógicos. Quarenta estudantes, com idades entre 14 e 18 anos, pertencentes a três escolas da cidade de Bauru, foram questionados sobre suas concepções alternativas acerca do fenômeno de formação das fases da Lua. Foi observado que alguns dos alunos confundem o fenômeno da formação das fases da Lua com o fenômeno da formação dos eclipses lunares, outros desconhecem o motivo do fenômeno, apresentam concepções alternativas incoerentes com a realidade ou então concepções incompletas. Os resultados aqui encontrados são destinados aos professores do Ensino Básico e poderão ser usados como subsídio parafuturo desenvolvimento de

  3. [The Spanish AIDS Study Group and Spanish National AIDS Plan (GESIDA/Secretaría del Plan Nacional sobre el Sida) recommendations for the treatment of tuberculosis in HIV-infected individuals (Updated January 2013)].

    PubMed

    Rivero, Antonio; Pulido, Federico; Caylá, Joan; Iribarren, José A; Miró, José M; Moreno, Santiago; Pérez-Camacho, Inés

    2013-12-01

    This consensus document was prepared by an expert panel of the Grupo de Estudio de Sida (GESIDA [Spanish AIDS Study Group]) and the Plan Nacional sobre el Sida (PNS [Spanish National AIDS Plan]). The document updates current guidelines on the treatment of tuberculosis (TB) in HIV-infected individuals contained in the guidelines on the treatment of opportunistic infections published by GESIDA and PNS in 2008. The document aims to facilitate the management and treatment of HIV-infected patients with TB in Spain, and includes specific sections and recommendations on the treatment of drug-sensitive TB, multidrug-resistant TB, and extensively drug-resistant TB, in this population. The consensus guidelines also make recommendations on the treatment of HIV-infected patients with TB in special situations, such as chronic liver disease, pregnancy, kidney failure, and transplantation. Recommendations are made on the timing and initial regimens of antiretroviral therapy in patients with TB, and on immune reconstitution syndrome in HIV-infected patients with TB who are receiving antiretroviral therapy. The document does not cover the diagnosis of TB, diagnosis/treatment of latent TB, or treatment of TB in children. The quality of the evidence was evaluated and the recommendations graded using the approach of the Grading of Recommendations Assessment, Development and Evaluation Working Group. PMID:23541879

  4. Efectos combinados de la ampliación de la atención primaria de salud y de las transferencias condicionadas de dinero en efectivo sobre la mortalidad infantil en Brasil, 1998–2010*

    PubMed Central

    Guanais, Frederico C.

    2015-01-01

    Objetivos. Examiné los efectos combinados del acceso a la atención primaria mediante el Programa de Salud Familiar (PSF) y las transferencias condicionadas de dinero en efectivo del Programa Bolsa Familia (PBF) sobre la mortalidad infantil posneonatal (MIPN) en Brasil. Métodos. Empleé un análisis ecológico longitudinal usando datos en panel de 4 583 municipios brasileños de 1998 al 2010, con 54 253 observaciones en total. Estimé modelos de regresión de efectos fijos por mínimos cuadrados ordinarios, con la tasa de MIPN como la variable dependiente y el PSF, el PBF y sus interacciones como las principales variables independientes de interés. Resultados. La asociación de una mayor cobertura del PSF con una menor tasa de MIPN se volvió más fuerte conforme aumentaba la cobertura del PBF. En los promedios de todas las demás variables, cuando la cobertura de PBF era 25%, la MIPN predicha fue 5,24 (intervalo de confianza [IC] de 95% = 4,95, 5,53) para una cobertura del PSF de 0%, y de 3,54 (IC de 95% = 2,77, 4,31) para una cobertura del PSF de 100%. Cuando la cobertura del PBF era de 60%, la MIPN predicha fue 4,65 (IC de 95% = 4,36, 4,94) para una cobertura del PSF de 0%, y de 1,38 (IC de 95% = 0,88, 1,89) para una cobertura del PSF de 100%. Conclusiones. El efecto del PSF depende de la ampliación del PBF. Para las poblaciones empobrecidas y subatendidas, la combinación de intervenciones tanto del lado de la oferta como del lado de la demanda podría ser necesaria para mejorar los resultados en salud.

  5. High School Students' Previous Knowledge about the Stars. (Spanish Title: Conocimientos Previos de Estudiantes de Secundaria Acerca de Las Estrellas.) O Conhecimento Prévio de Alunos do Ensino Médio sobre as Estrelas

    NASA Astrophysics Data System (ADS)

    Iachel, Gustavo

    2011-12-01

    Based on the readings of articles related to Astronomy Education published in Brazil, it was noticed a lack of research on previous knowledge of students about the physical characteristics of stars, a fact that motivated us to develop this study. Previous knowledge of 125 students (approximated 15 years old) constituted the study sample; data was collected through written questionnaires (Appendix A) for analysis. From the content analysis of these responses it was possible to achieve some inferences as, for example, many students have some difficult to develop an explanatory model on the functioning of a star; there are few who say that the stars have a certain length of existence; some students have said that stars have tips; few recognize that a star is formed by a mass of gas; some previous knowledge come from purely visual aspects; furthermore, some students do not have the habit of observing nature in detail. We see this research as a reference in which science teachers can recognize the importance of previous knowledge for practice teaching and acquire resources for planning their lessons. De la lectura de artículos relacionados con la Educación en Astronomía publicados en el Brasil, se encuentra una falta de investigaciones acerca del conocimiento previo de los estudiantes sobre las características físicas de las estrellas, hecho que nos motivó a desarrollar este estudio. Los datos analizados se obtuvieron al aplicar un cuestionario a 125 estudiantes de secundaria, para posteriormente realizar un análisis de contenido, tal cuestionario se presenta en el Anexo A. Al realizar el análisis de contenido de las respuestas obtenidas, fue posible hacer algunas inferencias, como por ejemplo; muchos estudiantes tienen dificultades para desarrollar un modelo explicativo acerca del funcionamiento de una estrella; pocos estudiantes dicen que las estrellas tienen un cierto tiempo de vida; algunos estudiantes imaginan que las estrellas tienen puntas; pocos

  6. Reflecting on Character (Reflexionando Sobre el Caracter).

    ERIC Educational Resources Information Center

    Candelaria, Cordelia

    1980-01-01

    Responding to the "Proyecto Resolana" article in the July/August 1980 issue of this journal, the article notes the heterogeneity of Hispanic Americans, the three main effects of the European conquest on people of the Western Hemisphere, and attempts to further define the character of Hispanic Americans. (SB)

  7. Reflecting on Language. (Reflexionando Sobre el Idioma.)

    ERIC Educational Resources Information Center

    Mazas, Jose Garcia

    1980-01-01

    Covering a 500-year span, this article traces the changes in and evolution of the Spanish language from its earliest written accounts in the eleventh century to the Spanish that was brought by the Conquistadores to the New World. (DS)

  8. Reflecting on Culture. (Reflexionando Sobre la Cultura.)

    ERIC Educational Resources Information Center

    Irizarry, Estelle

    1980-01-01

    The article comments on two articles, previously published in the same journal, which address the relationship between the "little" cultural tradition of Chicanos, Cubans, and Puerto Ricans and the "great" tradition of Hispanic arts and letters. Notes similarities among these groups and calls for the banding together of Hispanic artists. (SB)

  9. Sobre | Smokefree Español

    Cancer.gov

    Espanol.smokefree.gov ofrece apoyo y recursos para norteamericanos que hablan español y quieren dejar de fumar. Este sitio en la red fue creada por la División de Investigación para el Control del Tabaco del Instituto Nacional del Cáncer.

  10. Nota sobre "Neblina" (Notes on "Neblina")

    ERIC Educational Resources Information Center

    De Bruyne, Jacques

    1974-01-01

    Suggests that the Royal Spanish Academy change the definition of "neblina" in the next edition of the "Dictionary of the Spanish Language" to "niebla ligera" or "light fog," and cites literary usage in support. (Text is in Spanish.) (CK)

  11. Learning about the Sky from the Environment: An Experience Working Along One Year with Students of Elementary Education. (Spanish Title: Aprendiendo sobre EL Cielo Desde el Entorno: Una Experiencia Trabajando Durante un Año Junto a Estudiantes del Primario.) Aprendendo sobre o Céu a Partir do Entorno: Uma Experiência de Trabalho ao Longo de um Ano com Alunos de Ensino Fundamental

    NASA Astrophysics Data System (ADS)

    Longhini, Marcos Daniel; Gomide, Hanny Angeles

    2014-12-01

    Research developed with 95 students of the 6th year of elementary education in a public school of Uberlândia, Minas Gerais. It was a continuous work from February to December 2013, which led the students to participate in activities of observation of the environment, specifically the sky, analyzing the changes occurred. We focused on the study of variations in temperature, rainfall, day length, variations in the size of the shadows and changes in the aspect of the Moon. Our focus of analysis targeted the discussion of the knowledge that these students had about the topics indicated and as they entered the stage during the implementation of the proposal. The results showed a limited perception that students have of their environment, however, lately expanded due to the undertaken activities, especially in relation to the Moon. Working with systematic measure procedures reveals the careful handling of data so that they become understandable to students, and working with the shadows points towards the students first understand how shadows are formed, and then apply this knowledge to Astronomy. Finally, we conclude that the lived process consisted of an initial step of a work that should be encouraged for the subsequent years of training of these students. Proyecto de investigación desarrollado con 95 alumnos del sexto año de primaria en una escuela pública de Uberlândia, Minas Gerais. Fue un trabajo continuo, de febrero a diciembre de 2013, que llevó a los estudiantes a participar en actividades de observación de su entorno, entre ellas, el cielo, analizando los cambios ocurridos. Nos centramos en el estudio de las variaciones en la temperatura, las precipitaciones, la duración del día, las variaciones en el tamaño de las sombras y los cambios en los aspectos de la Luna. Nuestro foco de análisis se centró en discutir el conocimiento que estos estudiantes tenían sobre los temas indicados al inicio y término de la propuesta. Los resultados mostraron una

  12. A Proposed Activity for a Meaningful Learning about the Moon Phases. (Breton Title: Uma Proposta de Atividade Para a Aprendizagem Significativa sobre as Fases da Lua.) Una Actividad Propuesta Para EL Aprendizaje Significativo Acerca de Las Fases de la Luna

    NASA Astrophysics Data System (ADS)

    Martins, Bruno Andrade; Langhi, Rodolfo

    2012-12-01

    This paper presents one of the concepts of Astronomy and its consequent failure in teaching this topic in high school, even when the official documents point out the necessity of Astronomy teaching at this school level. Among the spontaneous conceptions in Astronomy that high school students carry with them, even after the end of the school, we emphasized in this research the Moon phases. The development of different strategies in relation to traditional methods, aimed to teaching-learning process on this topic was considered in this study. These strategies were devised based on the reference frame of the Meaningful Learning, as elaborated by Ausubel. The proposals presented here include the active participation of students in experimental activities and other didactic activities, for their continuous evaluation during the process. These activities finished with a Comics elaboration about the Moon phases. Therefore, the objective of this paper is to present a proposal for differentiated teaching activity about Moon phases supported by the theoretical principles of Meaningful Learning at Physics classes. Este texto foca um dos conteúdos de Astronomia e a consequente falha no ensino deste tema no ensino médio, apesar de os documentos oficiais apresentarem a necessidade de se trabalhar a Astronomia neste nível de ensino. Dentre as concepções alternativas em Astronomia que os alunos do ensino médio carregam consigo, mesmo após o término dos estudos, destacamos, nesta pesquisa, o fenômeno das fases da Lua. O desenvolvimento de estratégias diferenciadas em relação ao ensino tradicional, visando o processo de ensino-aprendizagem sobre este tema, foi contemplado neste trabalho como um dos resultados obtidos sob a luz dos referenciais da aprendizagem significativa, fundamentados em Ausubel. Segundo a proposta aqui apresentada, a participação ativa dos alunos na execução de uma atividade experimental e outras atividades didáticas, que visam sua cont

  13. Preparation of graphene thin films for radioactive samples.

    PubMed

    Roteta, Miguel; Fernández-Martínez, Rodolfo; Mejuto, Marcos; Rucandio, Isabel

    2016-03-01

    A new method for the preparation of conductive thin films is presented. The metallization of VYNS films guarantees the electrical conductivity but it results in the breaking of a high proportion of them. Graphene, a two-dimensional nanostructure of monolayer or few layers graphite has attracted a great deal of attention because of its excellent properties such as a good chemical stability, mechanical resistance and extraordinary electronic transport properties. In this work, the possibilities of graphene have been explored as a way to produce electrical conductive thin films without an extra metallization process. The procedure starts with preparing homogenous suspensions of reduced graphene oxide (rGO) in conventional VYNS solutions. Ultra-sonication is used to ensure a good dispersibility of rGO. Graphene oxide (GO) is prepared via oxidation of graphite and subsequent exfoliation by sonication. Different chemically rGO were obtained by reaction with hydrazine sulfate, sodium borohydride, ascorbic acid and hydroiodic acid as reducing agents. The preparation of the thin graphene films is done in a similar way as the conventional VYNS foil preparation procedure. Drops of the solution are deposited onto water. The graphene films have been used to prepare sources containing some electron capture radionuclides ((109)Cd, (55)Fe, (139)Ce) with an activity in the order of 3kBq. The samples have been measured to test the attainable low energy electron efficiency and the energy resolution of Auger and conversion electrons by 4π (electron capture)-γ coincidence measurements. The 4π (electron capture)-γ coincidence setup includes a pressurized proportional counter and a NaI(Tl) detector. Tests with different pressures up to 1000kPa were carried out. All these tests show similar values in both parameters (efficiency and resolution) as those obtained by using the conventional metallized films without the drawback of the high percentage of broken films. PMID:26651168

  14. Experiencias sobre el impacto del Programa de Formación en Ética de la Investigación Biomédica y Psicosocial en el ámbito de la salud mental y la investigación conductual.

    PubMed

    Barrios, Liliana Mondragón

    2012-01-01

    El propósito de este trabajo es presentar el impacto y la integración que los conocimientos adquiridos en el Programa Internacional de Formación en Ética de la Investigación Biomédica y Psicosocial de la Universidad de Chile han tenido en mi experiencia profesional, en el ámbito de la investigación psicosocial en un Instituto de Salud de México. Para este objetivo, expondré tres áreas en las cuales se ha podido evidenciar tal impacto: trabajo en los comités de ética, desarrollo de programas de académicos en bioética e investigación y publicación sobre ética y bioética. El motivo que me llevó a incursionar en el Programa fue que su enseñanza vincula la investigación psicosocial con la ética y la bioética, lo cual me permitió dirigir este tipo de reflexión hacia problemas como violencia, suicidio, adicciones, depresión y salud mental, y a nuevos campos como los estudios comunitarios, con poblaciones en riesgo o vulnerables, en los cuales las diversas implicaciones son difíciles de indagar. PMID:22754085

  15. Experiencias sobre el impacto del Programa de Formación en Ética de la Investigación Biomédica y Psicosocial en el ámbito de la salud mental y la investigación conductual

    PubMed Central

    Barrios, Liliana Mondragón

    2012-01-01

    El propósito de este trabajo es presentar el impacto y la integración que los conocimientos adquiridos en el Programa Internacional de Formación en Ética de la Investigación Biomédica y Psicosocial de la Universidad de Chile han tenido en mi experiencia profesional, en el ámbito de la investigación psicosocial en un Instituto de Salud de México. Para este objetivo, expondré tres áreas en las cuales se ha podido evidenciar tal impacto: trabajo en los comités de ética, desarrollo de programas de académicos en bioética e investigación y publicación sobre ética y bioética. El motivo que me llevó a incursionar en el Programa fue que su enseñanza vincula la investigación psicosocial con la ética y la bioética, lo cual me permitió dirigir este tipo de reflexión hacia problemas como violencia, suicidio, adicciones, depresión y salud mental, y a nuevos campos como los estudios comunitarios, con poblaciones en riesgo o vulnerables, en los cuales las diversas implicaciones son difíciles de indagar. PMID:22754085

  16. The Meanings of Astronomical Observation: An Analysis on the Basis of Relationship with Knowledge. (Spanish Title: Los Sentidos de la Observación Astronómica: un Análisis sobre la Base de la Relación con el Saber.) Os Sentidos da Observação Astronômica: Uma Análise com Base na Relação com o Saber

    NASA Astrophysics Data System (ADS)

    Klein, Alberto Eduardo; de Mello Arruda, Sergio; Meneghello Passos, Marinez; Vinicius Domenes Zapparoli, Ferdinando

    2010-12-01

    This article presents results of a research which aimed to understand the meanings that people construct for astronomical observation. The subjects, students and school teachers, initially received some instruction on how to view astronomical objects through the telescope. After the observation was realized, they were interviewed. The data analysis allowed the creation of 12 categories, later interpreted on the basis of relationship with knowledge (relation to the world, with himself and with others), as presented by Bernard Charlot. Este artículo presenta los resultados de una investigación que tuvo como objetivo comprender los sentidos que las personas construyen para la observación astronómica. Los sujetos, los estudiantes y maestros de escuela, recibieron inicialmente algunas instrucciones sobre cómo ver los objetos astronómicos a través del telescopio. Al término de la observación, fueron entrevistados. El análisis de datos permitió la creación de 12 categorías que más tarde fueron interpretadas sobre la base de la relación con el conocimiento (relación con el mundo, consigo mismo y con los demás), tal como presentado por Bernard Charlot. Este artigo apresenta resultados de uma pesquisa que objetivou entender quais os sentidos que as pessoas constroem para a observação astronômica. Os sujeitos da pesquisa, estudantes e professores do ensino médio, receberam inicialmente alguma instrução sobre como visualizar os objetos astronômicos através do telescópio. Após a realização da observação, eles foram entrevistados. A análise dos dados permitiu a elaboração de 12 categorias que foram posteriormente interpretadas com base nas relações com o saber (relação com o mundo, consigo mesmo e com o outro), conforme apresentadas por Bernard Charlot.

  17. Mixed-Methods Study that Examines Nine Science Teachers' Perceptions of Slooh Robotic Telescope for Teaching Astronomy. (Breton Title: Métodos Mistos de Estudo que Examinam a Percepção de Nove Professores de Ciências sobre o Telescópio Robótico Slooh Para Ensino de Astronomia.) Métodos Mixtos de Estudio que Examinan la Percepcion de Nueve Profesores de Ciencias sobre EL Telescopio Robótico Slooh Para la Enseñanza de la Astronomía

    NASA Astrophysics Data System (ADS)

    Gershun, Daniel C.; Slater, Timothy F.; Berryhill, Katie J.

    2014-07-01

    Although previous studies show that robotic telescopes have the potential to enhance student learning, there is comparatively little research that focuses on teacher perceptions of this technology. This study investigates: "what is the academic merit of using SLOOH robotic telescopes to teach astronomy as perceived by science teachers?" Our sample consists of nine science teachers of students aged 13-18 years. Pre- and post-tests, interviews, and surveys were collected during two weeks of a summer online course about robotic telescopes. While pre and post-tests do not reveal a statistically significant gain in astronomy content knowledge, analysis of qualitative data reveals five themes which describe the most important aspects of using SLOOH according to participants: "Images," "Interface," "Classroom Application," "Instructor Impact," and "Logistical Issues." Analysis of these themes suggests that SLOOH can provide an interactive and social learning environment with capabilities to incorporate crossdisciplinary themes. Embora estudos anteriores mostram que os telescópios robóticos têm o potencial de melhorar a aprendizagem dos alunos, há relativamente pouca investigação focada nas percepções de professores a respeito desta tecnologia. Este estudo investiga: "qual é o mérito acadêmico da utilização de telescópios robóticos Slooh para ensinar astronomia, tal como percebido pelos professores de ciências?" Nossa amostra é composta por nove professores de ciências de estudantes com idades entre 13-18 anos pré e pós-testes, entrevistas, e levantamentos foram coletados durante duas semanas de um curso on-line de verão sobre telescópios robóticos. Enquanto os testes pré e pós não revelaram um ganho estatisticamente significativo no conhecimento do conteúdo astronomia, a análise de dados qualitativos revela cinco temas que descrevem os aspectos mais importantes da utilização Slooh de acordo aos participantes: "Imagens", "Interface", "Aplica

  18. 77 FR 13376 - Notice of License Termination for the University of Arizona Research Reactor, License No. R-52

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-06

    ... above the Co-60 screening level in source pit number 2. Since confirmatory surveys occurred, surface activity in source pit 2 has been remediated to a value below the Co-60 screening level. The second issue... to re-calculate surface activity using the correct surface efficiency value for Co-60. Because...

  19. Reflexiones Sobre Investigacion Educacional (Reflections on Educational Research).

    ERIC Educational Resources Information Center

    Valle, Victor M.

    Educational research can serve to improve education in both developed and developing countries. It can be oriented toward increasing knowledge about the educational reality, generating theories, or confirming immediate educational political decisions. Educational research should be an interdisciplinary undertaking; this variety helps to unify…

  20. Proposiciones Sobre Autonomia Universitaria. (Propositions on University Autonomy).

    ERIC Educational Resources Information Center

    Valle, Victor M.

    University autonomy is a concept widely discussed and often misunderstood. In the Latin American context, university autonomy has been regarded as something inherent to the nature of the universities. As long as universities exist, the phenomenon of university autonomy will be present . University autonomy should be examined in the light of such…

  1. Los ojos de la NASA sobre la Tierra

    NASA Video Gallery

    La NASA cuenta con más de una decena de satélites que estudian la Tierra. Conoce la información que recaban los satélites, junto con Gilberto Colón, asistente especial del subdirector del Centro de...

  2. Epilepsy. Fact Sheet = Epilepsia. Hojas Informativas Sobre Discapacidades.

    ERIC Educational Resources Information Center

    National Information Center for Children and Youth with Disabilities, Washington, DC.

    This fact sheet, written in both English and Spanish, provides a definition, information on incidence, typical characteristics, and educational implications of epilepsy. It notes that epilepsy is classified as "other health impaired" under the Individuals with Disabilities Education Act (IDEA) and that children with epilepsy or seizure disorders…

  3. Spina Bifida. Fact Sheet = Espina Bifida. Hojas Informativas Sobre Discapacidades.

    ERIC Educational Resources Information Center

    National Information Center for Children and Youth with Disabilities, Washington, DC.

    This fact sheet offers definitions of the three types of spina bifida (spina bifida occulta, meningocele, and myelomeningocele), outlines their incidence, describes characteristics of individuals with spina bifida, and reviews educational implications. The fact sheet discusses the need for many children with myelomeningocele to learn to manage…

  4. Emotional Disturbance. Fact Sheet = Problemas Emocionales. Hojas Informativas Sobre Discapacidades.

    ERIC Educational Resources Information Center

    National Information Center for Children and Youth with Disabilities, Washington, DC.

    This fact sheet, written in both English and Spanish, provides a definition, information on incidence, typical characteristics, and educational implications of emotional disturbance. The definition is from the Individuals with Disabilities Education Act (IDEA) and incidence in 1999-2000 is reported as about 470,000 children and youth. Educational…

  5. Estudios sobre Educacion, 2002 (Studies on Education, 2002).

    ERIC Educational Resources Information Center

    Estudios sobre Educacion, 2002

    2002-01-01

    This journal, which provides abstracts of its articles mostly in Spanish and a few in English, contains studies (estudios) and notes (notas) about educational issues, as well as relevant book reviews (recensiones). Studies in this issue (No. 3, 2002) are: "Unprotected Time of Early Adolescence and Intergenerational Relations: A New Educational…

  6. Estudios sobre Educacion, 2002 (Studies on Education, 2002).

    ERIC Educational Resources Information Center

    Estudios sobre Educacion, 2002

    2002-01-01

    This scholarly journal deals with the study of education. Articles in this second issue are: "La Vertebracion Academica de la Formacion Inicial del Profesorado" (The Academic Backbone of the Initial Formation of Teachers) (Jose M. Esteve); "Deficiencia Visual en el Nino" (Visual Deficiency in the Young Child) (Feli Peralta; Juan Narbona); "The…

  7. [Parenting Information. Informacion Sobre Como Ser Padres Mejores.

    ERIC Educational Resources Information Center

    Moreno, Steve

    These five booklets, containing information on how parenting can effect children's school achievement, are part of a series of 22 innovative booklets designed specifically to help parents understand and help their children learn. Booklet #1, "Parents--Teach Your Children to Learn [Before They Go to School]," defines intelligence and suggests…

  8. [Parenting Information: Teenagers. Informacion Para los Padres: Sobre los Jovenes.

    ERIC Educational Resources Information Center

    Moreno, Steve

    These four booklets are devoted specifically to the concerns of parents and their teenage children and are part of a series of 22 booklets designed specifically to help parents understand their children and help them to learn. "Parents--Learn about Your Teenager" (booklet #6) explains the changes which occur during the teen years and the reasons…

  9. Apuntes sobre Latinismos en Espanol (Notes on Latinisms in Spanish)

    ERIC Educational Resources Information Center

    Perez B., L. A.

    1977-01-01

    Several Latinisms appear in Latin American Spanish, which would logically be farther from its Latin roots than Spanish in Spain. The existence of these elements and their importance as linguistic facts is analyzed here. Four words are treated: "Cliente,""cuadrar,""cuarto" and "rabula." (Text is in Spanish.) (CHK)

  10. Um Olhar sobre "Beleza Americana" (A Look at "American Beauty").

    ERIC Educational Resources Information Center

    Bissoto, Maria Luisa

    2000-01-01

    Discusses the film "American Beauty" in light of a reading of Karl Marx. Finds that the film shows the circularity which marks bourgeois society, even though the rhythm of industry and renovation of the society masks it. States that Marx praises the industry, invention, and innovation of the bourgeoisie. (BT)

  11. [Parenting Information: Drugs. Informacion Para los Padres: Sobre las Drojas.

    ERIC Educational Resources Information Center

    Moreno, Steve

    These two booklets provide basic information about drugs and drug abuse and are part of a series of 22 booklets, designed specifically to help parents understand their children and help them to learn. "Let's Talk about Drug Abuse," (booklet #18), reviews foreign substances or drugs young people are often exposed to (i.e., tobacco, alcohol,…

  12. Iniciativa sobre Efectividad: Primeros frutos (Initiative about Effectiveness: First Fruits).

    ERIC Educational Resources Information Center

    Moreno Garcia, Teresa, Ed.

    2001-01-01

    This Spanish- and Portuguese-language bulletin is a follow-up to No. 15 (PS 030 558), which examined some Effectiveness Initiative (EI) projects. This issue presents some beginning efforts to reflect on what has been learned through EI and to draw conclusions. The articles cover the results of EI projects from such angles as their relations with…

  13. Questions about Brain Development = Preguntas sobre el desarrollo del cerebro.

    ERIC Educational Resources Information Center

    Southeastern Regional Vision for Education (SERVE), Tallahassee, FL.

    Noting that new research shows that a baby's earliest years shape how he or she grows later in life, this brochure, in English- and Spanish-language versions, provides brief answers to some important questions parents may have about their baby's brain. The questions answered are: (1) "Why is brain development a popular subject lately?; (2) "What…

  14. Memories of Astronomy Education in Brazil: Clippings from the Discourses of Interviewed Researchers on the Subject. (Spanish Title: Memorias de la Educación en Astronomía en Brasil: Recortes de los Discursos de Investigadores Entrevistados Acerca del Tema ) Memórias da Educação em Astronomia no Brasil: Recortes a Partir das Falas de Pesquisadores Entrevistados sobre o Tema

    NASA Astrophysics Data System (ADS)

    Iachel, Gustavo; Nardi, Roberto

    2014-12-01

    This paper presents a historical retrospective concerning data from a research in Astronomy Education in Brazil, after 1973. It was organized on the basis of the speech analysis of national researchers considered references in this field by their peers. Furthermore, it was elaborated on the basis of other studies from the areas of Science Education, Physics and Astronomy. This historical overview was developed in order to facilitate understanding of the contexts in which the interviewed researchers have developed professionally. Moreover, we attempted to recover the memory of the growing field of research in Astronomy Education in the country. We believe that the history presented can help those trying to understand the past in an attempt to resolve current and future demands. Se presenta en este artículo una retrospectiva histórica referente a datos provenientes de la investigación en enseñanza de la astronomía en el Brasil, después de 1973, organizada sobre la base del análisis de los discursos de los investigadores nacionales considerados referencias en este campo, y también en la lectura de las publicaciones en las áreas de Enseñanza de las Ciencias, Física y Astronomía. Este repaso histórico se desarrolló con el fin de facilitar la comprensión de los contextos en los que los investigadores entrevistados se han desarrollado profesionalmente. Por otra parte, se intentó recuperar la memoria del creciente campo de la investigación en Educación en Astronomía en el país. Creemos que el relato presentado puede contribuir a quien trata de comprender el pasado, en un intento de resolver las demandas actuales y futuras. Relata-se neste artigo uma retrospectiva histórica referente a dados provenientes de pesquisa em Educação em Astronomia no país, pós 1973, organizada com base na análise das falas de pesquisadores considerados referências nacionais nesse campo, como também na leitura de publicações das áreas de ensino de Ciências, F

  15. Ask about Chapter 1: Questions Parents Often Ask about Chapter 1 Programs = Pregunte sobre el capitulo 1: Preguntas que los padres frecuentemente hacen sobre el programa capitulo 1.

    ERIC Educational Resources Information Center

    RMC Research Corp., Hampton, NH.

    Chapter 1 is a program funded by the Federal Government to help children who are at a disadvantage in school. Parents have many questions about Chapter 1 programs. This brochure presents many of the questions that parents have asked over the years about how Chapter 1 works. Because every school district's Chapter 1 programs are different, the…

  16. Questions Parents Ask about Schools = Preguntas que hacen los padres sobre las escuelas. Revised.

    ERIC Educational Resources Information Center

    Department of Education, Washington, DC. Office of Intergovernmental and Interagency Affairs.

    Noting that parents play an important role in the school success of their elementary- and middle-school-aged children, this booklet offers research-based tips to provide both practical guidance and information about a range of education-related topics. Presented in a question-answer format in both English and Spanish versions, the booklet provides…

  17. Homework Tips for Parents = Consejos para los padres sobre la tarea escola.

    ERIC Educational Resources Information Center

    Department of Education, Washington, DC. Office of Intergovernmental and Interagency Affairs.

    Homework has been a part of students' lives since the beginning of formal school in the United States; the push for increased homework has increased, fueled by rising academic standards. Noting that parents involved can have either a positive or a negative influence on the value of homework, this booklet, in both English and Spanish, offers…

  18. Recopilacion Bibliografica Sobre Investigacion y Cambio Cultural (Bibliographic Compilation about Cultural Investigation and Exchange).

    ERIC Educational Resources Information Center

    Centro Latinoamericano de Educacion de Adultos, Santiago (Chile).

    The bibliography forms part of a project to define guidelines for a method of cultural investigation in the education of adults. A brief introduction is followed by a list of libraries and the plan for the listing of entries in the bibliography. Entries are arranged alphabetically by author under the following general headings: background on the…

  19. Nueva investigacion sobre kindergarten de dia completo (Recent Research on All-Day Kindergarten). ERIC Digest.

    ERIC Educational Resources Information Center

    Clark, Patricia

    Noting that much of the early research on the effects of all-day kindergarten had serious problems with internal and external validity due to inadequate methodological standards, this Spanish-language digest reviews research conducted in the 1990s. The digest discusses the academic, social, and behavioral effects of all-day kindergarten, as well…

  20. Bibliografia sobre el "bilinguismo" del Paraguay (A Bibliography on Bilingualism in Paraguay)

    ERIC Educational Resources Information Center

    Melia, Bartomeu

    1974-01-01

    This bibliography of ninety-five entries ranging in publication date from 1847 to 1947 brings together information from areas of history, literature, sociology, anthropology, sociolinguistics, descriptive linguistics, folk-lore and language planning, the central criterion being the relationship of these areas specifically to the bilingual…

  1. Ahorre Energia: Consejos sobre el ahorro de dinero y energia en el hogar (Book)

    SciTech Connect

    Not Available

    2014-09-01

    Learn how to save money with Energy Saver: Tips on Saving Money & Energy at Home, from the U.S. Department of Energy. The Energy Saver guide will help you reduce your monthly energy costs and live more efficiently. This guide takes you through the systems and appliances that consume the most energy in your home, and provides solutions to cut costs for you while saving the environment. The Energy Saver guide also includes transportation tips to help you save money at the pump.

  2. Modelo analítico del efecto de PRS sobre satélites GPS

    NASA Astrophysics Data System (ADS)

    Meza, A.; Brunini, C.; Usandivaras, J. C.

    El sistema GPS (Global Position System) es, hoy en día, la herramienta de navegación y posicionamiento más potente y lo será sin duda en la próxima década. Gran parte de su valiosa utilidad se debe a la alta precisión que permite lograr y ésta, a su vez, depende, entre otras causas, de la precisión con que se conocen las órbitas de los satélites. La presión de radiación solar (PRS) fija el límite de la precisión con que pueden calcularse en la actualidad las efemérides satelitarias. El objetivo de este trabajo es proponer una mejor resolución de este fenómeno. El modelo analítico aquí presentado, se basa en el análisis del comportamiento de los residuos de un ajuste por mínimos cuadrados en el que se utiliza el modelo de PRS propuesto por Beutler. El mismo consiste en un modelo determinista del fenómeno con dos parámetros libres. Los resultados obtenidos ponen de manifiesto que, aún después de aplicar dichos parámetros, prevalecen en los residuos efectos semidiurnos en las componentes radial,tangencial y normal. Estos resultados obtenidos se comparan con los de un trabajo desarrollado por el Instituto de Berne (Beutler et al., 1994), en el que se utilizaron como pseudo-observaciones las órbitas precisas del IGS (CODE). El intervalo de integración escogido por este centro fueron las semanas 680 y 681. En resumen se tienen arcos de 14 días para todos los satélites, donde las efemérides precisas de los mismos para los 14 días fueron utilizados como pseudo-observaciones. El modelo de fuerza que empleó dicho centro fue básicamente el tradicional en lo que respecta al modelo de las fuerzas gravitacionales, y para la PRS utilizo el modelo standard de Beutler. Los parámetros de este modelo junto con las 6 condiciones iniciales (posición y velocidad) fueron ajustados por el método general de mínimos cuadrados. Los residuos en la componente radial, tangencial y normal, para los satélites con un buen comportamiento, presentan una componente semidiurna. El modelo analítico planteado en este trabajo, predice el comportamiento de los residuos que se observan en las publicaciones más recientes. Esto abre el camino para plantear una estimación distinta de las incógnitas del problema, basado en el método de colocación por mínimos cuadrados. Ello requiere modelar estadísticamente la señal debida a las componentes de la PRS que no son tomadas en cuenta en el modelo determinista.

  3. Reflexiones Sobre la Capacitacion de Docentes (Reflections on In-Service Teacher Training).

    ERIC Educational Resources Information Center

    Valle, Victor M.

    Everyone concerned with educational systems performance agrees that the improvement of teaching qualities is a high priority in any educational effort. Teachers are assigned the role of change agents and are presented with new challenges, e.g., to make education global and permanent, flexible enough to serve in any environment (in or out of the…

  4. Traumatic Brain Injury. Fact Sheet = Lesion Cerebral Traumatica (TBI). Hojas Informativas Sobre Discapacidades.

    ERIC Educational Resources Information Center

    National Information Center for Children and Youth with Disabilities, Washington, DC.

    This fact sheet, written in both English and Spanish, offers general information about traumatic brain injury. Information includes a definition, incidence, individual characteristics, and educational implications. The signs of traumatic brain injury are listed and include physical disabilities, difficulties with thinking, and social, behavioral,…

  5. Mental Retardation. Fact Sheet = El Retraso Mental. Hojas Informativas Sobre Discapacidades.

    ERIC Educational Resources Information Center

    National Information Center for Children and Youth with Disabilities, Washington, DC.

    This fact sheet on mental retardation is written in both English and Spanish. It begins with a vignette of a 15-year-old boy with mental retardation. Mental retardation is briefly explained as are some causes of mental retardation. It notes that a diagnosis of mental retardation looks at two things: first, the ability of a person's brain to learn,…

  6. Speech and Language Disorders. Fact Sheet = Trastornos del Habla y Lenguaje. Hojas Informativas Sobre Discapacidades.

    ERIC Educational Resources Information Center

    National Information Center for Children and Youth with Disabilities, Washington, DC.

    This fact sheet on speech and language disorders is presented in English and Spanish. It provides information on the definition of speech and language disorders and possible causes; the incidence (about one in ten people); and characteristics of delayed communication, speech disorders, and language disorders. It notes educational implications,…

  7. Sobre la ensenanza de la literatura hispanoamericana (The Teaching of Hispanoamerican Literature).

    ERIC Educational Resources Information Center

    Ellis, Keith

    There are three main problems in teaching Latin American literature: (1) It is difficult to maintain a regional overview, while, at the same time, including a sense of the literary history of Latin America; (2) It is necessary to teach literature so that the material seems worthwhile in its own right and not only as a complement to other…

  8. Profesionalismo: Un estudio fenomenologico sobre experiencias de universitarios en programas de salud

    NASA Astrophysics Data System (ADS)

    Lopez Ortiz, Wilma J.

    Some studies suggest that, upon admission, medicine programs students display eagerness for community service, aspirations to be useful, and to contribute to society's well-being. Those same studies reflect that qualities of idealism, moral nature, and internal motivation, suffer a subsequent diminishing. The researchers inferred that the main reason for this process of change in the mood and disposition of these future physicians lies in the modeling they receive from medical professionals throughout clinical learning activities, by way of behavior and relationships exhibited during daily interaction with peers, patients and the students themselves. This phenomenological study used a cross-sectional sample to explore the experiences of future health workers as they went through didactic and clinical phases of their training curriculum. The study employed semi-structured interviews and reflective journals to explore those experiences and to discover the meanings ascribed by the participants. The analysis revealed that the students defined "professionalism" in terms of scientific knowledge, commitment, respect for human dignity, comradeship, courtesy, empathy, integrity, altruism, motivation. They also described their feelings as they went through the didactic and clinical experiences, and recognized as very important the extracurricular activities of community service, describing them as useful opportunities which contributed to understand their work in terms of a mission dedicated to the achievement of the social benefit. From their individual perspectives, the clinical environment could, in general, be described as congruent with those characteristics of professionalism. During the study we had the opportunity to share, in a little deeper way, the environment... the world... of this small group of young students as we went on trying to decipher their feelings and thoughts. At the end, we realized the richness of their sensibilities, we perceived the intensity of their moral and ethical convictions, we were able to understand their concerns, worries, struggles and efforts. This life event had profound and significant repercussions in our personal and professional life. As a result, and from now on, we will no longer look at our young scholars and apprentices without imagining a noble spirit, with goals which at times could seem unattainable... without completely visualizing or conceiving real hope for a better country.

  9. Recursos de Trabajo: Informacion sobre Carreras (Occupational Resources: Career Information). CHOICE (Challenging Options in Career Education).

    ERIC Educational Resources Information Center

    Putnam and Northern Westchester Counties Board of Cooperative Educational Services, Yorktown Heights, NY.

    Part of a two-level career education curriculum initially developed for migrant children, the book is the first of three secondary level texts designed to provide high school students with self-awareness, job and role information, and decision-making/goal attaining information related to career education. The text provides job and role information…

  10. Como preparar un programa de informacion sobre la asistencia economica (Planning a Financial Aid Awareness Program).

    ERIC Educational Resources Information Center

    Department of Education, Washington, DC.

    This booklet, written in Spanish, is intended to be used with a set of slides as part of a presentation to students on "How To Apply for Federal Student Aid" ("Como Solicitar la Asistencia Economica Federal para Estudiantes"). The first part of the book is a script based on the slides. After the script is a guide to hosting a financial aid…

  11. Simposio interamericano sobre administracion de la educacion (Inter-American Symposium on Educational Administration).

    ERIC Educational Resources Information Center

    Cespedes, Francisco S., Ed.

    The presidents and foreign ministers in Latin America recognize the importance of applying technology to school administration as the first step in any educational reform. In October 1968, the Organization of American States (OAS) [Organizacion de los Estados Americanos (OEA)], sponsored a symposium in Brasilia, Brazil, in cooperation with the…

  12. Cerebral Palsy. Fact Sheet = La Paralisis Cerebral. Hojas Informativas Sobre Discapacidades.

    ERIC Educational Resources Information Center

    National Information Center for Children and Youth with Disabilities, Washington, DC.

    This fact sheet on cerebral palsy is written in both English and Spanish. First, it provides a definition of cerebral palsy and considers various causes (e.g., an insufficient amount of oxygen reaching the fetal or newborn brain). The fact sheet then offers incidence figures and explains characteristics of the three main types of cerebral palsy:…

  13. Curso Introductorio sobre el Sistema DIALOG (Introductory Course on the DIALOG System).

    ERIC Educational Resources Information Center

    Rodriguez, Ketty

    As an introduction to the use of the DIALOG online retrieval service, this guide presents material that was developed during a fellowship at Carlos III University, School of Library Science and Documentation, Madrid (Spain) and that is based on a course on the same subject taught in English at Texas Women's University. Although the use of DIALOG…

  14. Cultural Diversity Awareness Inventory = Inventario Sobre el Reconocimiento de Diversas Culturas.

    ERIC Educational Resources Information Center

    Henry, Gertrude B.

    This booklet features a checklist designed to help persons who are involved in providing direct services to culturally diverse, young special needs children to assess their attitudes, beliefs, and behavior toward these children. The booklet also contains suggestions and lists of print, film, and filmstrip resources for developing a school program…

  15. Consideraciones sobre la Ansiedad en la Primera Infancia (Considerations Concerning Anxiety in Early Infancy).

    ERIC Educational Resources Information Center

    Muller, Elsa

    The results of an experience obtained while working with children in the early stages of infancy are presented. They are basically observations taken of a child's reaction to sudden changes, particularly separation from its mother. Anxiety was observed in these infants in diverse circumstances; in some cases it was at a normal level and in others…

  16. Questions Often Asked about Special Education Services = Preguntas sobre los servicios de educacion especial.

    ERIC Educational Resources Information Center

    Kupper, Lisa, Ed.

    This guide, available in both English and Spanish, answers questions often asked by parents about special education services. Questions and answers address the following topics: where to begin if a parent believes a child needs special education services, services available to very young children, the evaluation process, the Individualized…

  17. Preguntas y Respuestas sobre IDEA (Questions and Answers about the IDEA).

    ERIC Educational Resources Information Center

    Kupper, Lisa, Ed.

    1994-01-01

    This digest examines the mandates and requirements of the Individuals with Disabilities Education Act (IDEA). (Its scope does not include the IDEA's Part H program.) The digest gives a brief history of the IDEA, procedures for obtaining a copy of the IDEA and its regulations, and procedures for obtaining a copy of an individual state's special…

  18. Las Preguntas Que Hacen los Padres sobre la Escuela (Questions Parents Ask about School).

    ERIC Educational Resources Information Center

    National Opinion Research Center, Chicago, IL.

    This guide presents questions that parents frequently ask about their children's school along with answers to those questions. The questions and answers were prepared based on the results of studies conducted by the Partnership for Family Involvement in Education, the U.S. Department of Education, the GTE Foundation, and by the National Center for…

  19. Una Metodologia de Analisis de la Interaccion Alumno-Orgendaor en la Investigacion Sobre Informatica Educativa.

    ERIC Educational Resources Information Center

    Estepa, A.; And Others

    1992-01-01

    The recording of the interaction between pupil and computer is one of the data sources frequently used in research on the use of computers in teaching. Describes the analysis methodology of these recordings to determine the use of computers in statistics and its adaptation to other research work on the use of computers in education. (Author/MDH)

  20. Guia para los padres sobre educacion preescolar (A Parents' Guide to Early Childhood Education).

    ERIC Educational Resources Information Center

    Dodge, Diane Trister; Phinney, Joanna

    This handbook, entirely in Spanish, was originally intended for parents whose children attend programs which use "The Creative Curriculum for Early Childhood" (CCEC), but the information is also useful to parents whose children attend early childhood programs using other curriculum models based on child development theories. The purpose of the…

  1. Comunicado de prensa del Informe Anual sobre el Estado del Cáncer 2015

    Cancer.gov

    Por primera vez, los investigadores han usado datos a nivel nacional para determinar la incidencia de los cuatro subtipos moleculares principales de cáncer de seno (mama) por edad, raza y grupo étnico, nivel de pobreza y varios otros factores. El informe

  2. Notas sobre los Sonidos Consonantes en Espanol (Notes on Consonant Sounds in Spanish)

    ERIC Educational Resources Information Center

    Ezquerra, Raimundo

    1974-01-01

    This paper examines the Spanish phonetic system, as set forth by Navarro Tomas in his "Manual de Pronunciacion Espanola," and discusses the influences exerted by certain sounds over others. (Text is in Spanish.) (CK)

  3. Trabajos de fotometría de moderada precisión, sobre el cometa Halley.

    NASA Astrophysics Data System (ADS)

    Parachú, O. A.

    Experimental data to determine the visual magnitude of Comet Halley's head are presented. Two different ways are chosen; one using the photographical contours method and other one determining the visibility beginning time at evening twilight or the visibility extinction time at morning twilight.

  4. Consideracoes Historicas sobre o Ensino Profissionalizante no Brasil (Historical Considerations about Professional Education in Brazil).

    ERIC Educational Resources Information Center

    Barros, Marta Silene Ferreira

    2000-01-01

    Analyzes the paths taken in professional education in Brazil from the colonial period until the formation of the republic. Refers to specialists as well as specific laws for each period described in the study. (BT)

  5. Iniciativa sobre Efectividad: Un entorno para el aprendizaje (Initiative about Effectiveness: An Environment for Learning).

    ERIC Educational Resources Information Center

    Moreno Garcia, Teresa, Ed.

    2000-01-01

    This Spanish- and Portuguese-language bulletin presents articles focusing on the Effectiveness Initiative (EI), a project of the Bernard van Leer Foundation for making a qualitative analysis of those elements of the programs of Early Childhood Development (ECD) that benefit the participants and their communities and cultures. The first article…

  6. Perspectiva sobre una Personalidad Senera: Carmen Fischer Ramirez (Perspective on a Singular Personality: Carmen Fischer Ramirez).

    ERIC Educational Resources Information Center

    Quezeda, Dina Alarcon

    1992-01-01

    Traces the career of Carmen Fischer Ramirez, focusing on her work in improving early childhood education in Chile. Reviews her university career, work with the World Organization for Early Childhood Education, and major publications. (AC)

  7. SU-C-BRB-05: Investigation of Conformal Arc Therapy Utilizing Newly Designed Cobalt 60 Machine

    SciTech Connect

    Eldib, A; Chibani, O; Jin, L; Li, J; Veltchev, I; Price, R; Ma, C; Mora, G

    2015-06-15

    Purpose: A new modernized design for cobalt 60 (Co-60) machines is being developed with a ring type gantry. In this study we investigate the beneficial outcome of the new design for conformal arc therapy for various clinical sites. The new modality was evaluated based on isodose distributions and dose volume histograms as compared to 6MV photon beams from conventional linear accelerators. Methods: Computed tomographic images of seven different SBRT patients were selected from our patient database. All of these cases were previously planned on the Eclipse treatment planning system. New plans for these patients were generated with a modified conformal arc technique using both 6MV and Co-60 beams. The conformal arc was created by the delivery of treatment fields conformal to the target cross-section at every 5 or 10 degrees. The field shape was modified or turned off when it initially passed through a critical structure. Monte Carlo codes, MCBEAM and MCPLAN, were used for the machine head simulation and phantom/patient dose calculation, respectively. In the new Co-60 machine design, the source-to-isocenter distance was 60cm and the treatment head included the Co-60 source, primary collimator, jaws and MLC. Results: For all cases investigated, conformal arc plans utilizing Co-60 beams achieved similar conformity (mean conformity index=1.19) comparing to 6MV photon beams. Isodose distributions were tailored similarly around the PTV; both Co-60 and 6MV plans met our clinical acceptance criteria for the target coverage, and the maximum and minimum target doses. The DVH for the Co-60 plans showed slightly lower doses to the critical structures although the differences were small in most cases. Conclusion: There were no significant dosimetric differences between 6MV and Co-60 plans. Our results confirmed that this new Co-60 design could be a cost-effective machine for advanced radiotherapy due to its low cost, low maintenance and high up time.

  8. Intriguing results of stopping power measurements with light ions traversing several organic (Co) polymer targets

    NASA Astrophysics Data System (ADS)

    Porter, L. E.

    2001-07-01

    Previously published measurements of stopping powers of four organic (co)polymers for protons, alpha particles, and 7Li ions have been analyzed in terms of modified Bethe-Bloch theory. This procedure allows extraction of values of various parameters which constitute an integral part of the formalism, most notably the target mean excitation energy (I) and Barkas-effect parameter (b). Normally one can expect the extracted I-value to exceed by a few per cent the value based on the additivity assumption (IB), whereas the extracted b-value should lie within the expected interval of about 1.3-1.5. Results of one series of measurements with the same experimental arrangement, utilizing thin target foils of formvar (a polyvinylformyl resin), polysulfone, kapton (a polymide), and vyns (a vinylchloride-vinylacetate copolymer), yielded results quite consistent with expectation except that the extracted I-value for formvar lay about 20% below the value of IB. This salient anomaly will be examined in detail. Moreover, trends in extracted I- and b-values suggesting a dependence on projectile will be considered.

  9. The study of decreasing toxicity of cigarettes with the radiational technique

    NASA Astrophysics Data System (ADS)

    Chengkui, Tang; Yun, Zhang; Jinju, Xu

    This is a report of the decreasing toxicity of cigarettes. All results of different experimental methods used show that through Co 60-γ radiation treatment the amount of carcinogenic substance in the cigarette smoke condensate obviously decreased.

  10. Dose enhancement in a room cobalt-60 source

    SciTech Connect

    Simons, M.; Pease, R.L.; Fleetwood, D.M.; Schwank, J.R.; Krzesniak, M.

    1997-06-01

    A room Co-60 source was characterized using TLDs and pMOS RADFETs. Dose enhancement was measured using RADFETs with and without gold- flashed kovar lids. A methodology was developed to predict dose enhancement vs position and test configuration.

  11. The role of Cobalt-60 source in Intensity Modulated Radiation Therapy: From modeling finite sources to treatment planning and conformal dose delivery

    NASA Astrophysics Data System (ADS)

    Dhanesar, Sandeep Kaur

    Cobalt-60 (Co-60) units played an integral role in radiation therapy from the mid-1950s to the 1970s. Although they continue to be used to treat cancer in some parts of the world, their role has been significantly reduced due to the invention of medical linear accelerators. A number of groups have indicated a strong potential for Co-60 units in modern radiation therapy. The Medical Physics group at the Cancer Center of the Southeastern Ontario and Queen's University has shown the feasibility of Intensity Modulated Radiation Therapy (IMRT) via simple conformal treatment planning and dose delivery using a Co-60 unit. In this thesis, initial Co-60 tomotherapy planning investigations on simple uniform phantoms are extended to actual clinical cases based on patient CT data. The planning is based on radiation dose data from a clinical Co-60 unit fitted with a multileaf collimator (MLC) and modeled in the EGSnrc Monte Carlo system. An in house treatment planning program is used to calculate IMRT dose distributions. Conformal delivery in a single slice on a uniform phantom based on sequentially delivered pencil beams is verified by Gafchromic film. Volumetric dose distributions for Co-60 serial tomotherapy are then generated for typical clinical sites that had been treated at our clinic by conventional 6MV IMRT using Varian Eclipse treatment plans. The Co-60 treatment plans are compared with the clinical IMRT plans using conventional matrices such as dose volume histograms (DVH). Dose delivery based on simultaneously opened MLC leaves is also explored and a novel MLC segmentation method is proposed. In order to increase efficiency of dose calculations, a novel convolution based fluence model for treatment planning is also proposed. The ion chamber measurements showed that the Monte Carlo modeling of the beam data under the MIMiC MLC is accurate. The film measurements from the uniform phantom irradiations confirm that IMRT plans from our in-house treatment planning system

  12. Neutron capture production rates of cosmogenic 60Co, 59Ni and 36Cl in stony meteorites

    NASA Technical Reports Server (NTRS)

    Spergel, M. S.; Reedy, R. C.; Lazareth, O. W.; Levy, P. W.

    1986-01-01

    Results for neutron flux calculations in stony meteoroids (of various radii and compositions) and production rates for Cl-36, Ni-59, and Co-60 are reported. The Ni-59/Co-60 ratio is nearly constant with depth in most meteorites: this effect is consistent with the neutron flux and capture cross section properties. The shape of the neutron flux energy spectrum, varies little with depth in a meteorite. The size of the parent meteorite can be determined from one of its fragments, using the Ni-59/Co-60 ratios, if the parent meteorite was less than 75 g/cm(2) in radius. If the parent meteorite was larger, a lower limit on the size of the parent meteorite can be determined from a fragment. In C3 chondrites this is not possible. In stony meteorites with R less than 50 g/cm(2) the calculated Co-60 production rates (mass less than 4 kg), are below 1 atom/min g-Co. The highest Co-60 production rates occur in stony meteorites with radius about 250 g/cm(2) (1.4 m across). In meteorites with radii greater than 400 g/cm(2), the maximum Co-60 production rate occurs at a depth of about 175 g/cm(2) in L-chondrite, 125 g/cm(2) in C3 chrondrite, and 190 g/cm(2) in aubrites.

  13. Efecto de la dieta artificial MP sobre la emergencia y relacion de sexos de Phymastichus coffea (Hymenoptera:Eulophidae) mantenido sobre su hueped, Hypothenemus hampei (Coleoptera: Scloytidae)a traves de generaciones contin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phymastichus coffea La Salle (Hymenoptera: Eulophidae) is an endoparasitoid that attacks the adult coffee berry borer, Hypothenemus hampei Ferrari (Coleoptera: Scolytidae). The MP diet developed by Portilla and Streett is the only reported diet that allows cultures of P. coffea to develop and repr...

  14. Análise sobre o Conhecimento de um Grupo de Alunos do Ensino Médio da Rede Estadual de São Paulo sobre Termos e Fenômenos Astronômicos do Cotidiano

    NASA Astrophysics Data System (ADS)

    de Oliveira, E. F.; Voelzke, M. R.; Amaral, L. H.

    2007-08-01

    Embora os Parâmetros Curriculares Nacionais do Ensino Médio (PCN-EM) e as orientações complementares a esses Parâmetros (PCN+) apontem a importância de uma abordagem significativa de conceitos relacionados à astronomia nas aulas de Física, muitos estudantes terminam o Ensino Médio (EM) sem compreender a razão de certos acontecimentos de origem celeste, ainda que estes façam parte de seu cotidiano. Este trabalho tem por objetivo analisar os conhecimentos básicos em astronomia dos alunos de EM da escola estadual Batista Renzi, bem como investigar os meios através dos quais estes conhecimentos foram adquiridos. Para tanto foi elaborado um questionário de múltipla escolha aplicado a 310 alunos distribuídos entre as três séries do EM dos períodos matutino e noturno. Dessa forma, observou-se que apenas 34,5% relacionaram as estações do ano à inclinação do eixo de rotação da Terra, 21,3% indicaram a influência gravitacional da Lua e do Sol como responsáveis pelo fenômeno das marés, 24,5% indicaram corretamente quais são os objetos celestes mais próximos da Terra, 36,1% identificaram ano-luz como uma medida de distância e 34,2% reconheceram uma estrela cadente como meteoro. Em contrapartida, 67,1% compreendiam a sucessão entre dia e noite, 73,9% identificaram o Sol como estrela e 52,3% relacionaram o Big Bang à origem do Universo. Além disso, foram comparadas as respostas de alunos de diferentes séries e períodos, observando-se, dentre outras coisas, que os estudantes do terceiro ano apresentam um percentual de acertos semelhante ao dos alunos do primeiro, caracterizando que a abordagem de tópicos relacionados à astronomia no EM não tem contribuído para uma maior compreensão dos fenômenos e conceitos.

  15. Sobre as inclinações carnais: inflexões do pensamento cristão sobre os desejos e as sensações prazerosas do baixo corporali

    PubMed Central

    RIOS, LUÍS FELIPE; PARKER, RICHARD; TERTO, VERIANO

    2011-01-01

    On carnal inclinations: from early Christianity to the present This study develops a historical review of the meanings of the “flesh” in the West, focusing on its significance in the context of Christianity. Our hope is that a study along these lines can help to illuminate current understandings of questions related to sexuality both within and outside of the religious contexts found in contemporary Brazil. Such questions are of special interest for those who are concerned with both old and new problems found in the field that has come to be known as sexual and reproductive rights, with implications for the field of Public Health. PMID:21980215

  16. Validacion de un Inventario Sobre La Percepcion de Los Padres de Superdotados Respecto a Los Servicios Educativos Disponibles Para Estos

    ERIC Educational Resources Information Center

    Medina Munoz, Arlette Zamarie

    2013-01-01

    In Puerto Rico, there isn't a survey that collects the parent's perception of the available services for gifted children. Considering this, in this investigation an instrument was created and scientifically validated to collect the parents' perception of the educational services available. The instrument was validated using internal…

  17. El Conocimiento Ocupacional y del Yo para los Grupos Especiales. Monografias sobre el Conocimiento Ocupacional y del Yo.

    ERIC Educational Resources Information Center

    Hoyt, Kenneth B.

    This Spanish translation of ED 132 428 includes the three papers representing Office of Education attempts to face the need for improving delivery of career education to special portions of the population. New additions are brief sections on basic definitions and additional considerations of the significance of work. The first paper, on career…

  18. Una Guia de Consejos Practicos Sobre la Lectura para los Padres (A Guide to Reading Tips for Parents).

    ERIC Educational Resources Information Center

    Department of Education, Washington, DC.

    The No Child Left Behind program changes the federal role in education by asking America's schools to describe their success in terms of what each student accomplishes. The information in this reading guide, presented in Spanish, was developed by the United States Department of Education to assist parents, caregivers, and teachers in understanding…

  19. "O Que Diriam Sobre Os Portugueses?????" [What Would You Say about Portuguese People?]: Intercultural Curiosity in Multilingual Chat-Rooms

    ERIC Educational Resources Information Center

    Araujo e Sa, Maria Helena; de Carlo, Maddalena; Melo-Pfeifer, Silvia

    2010-01-01

    In this study, we intend to discuss questioning as a sign of Intercultural Communicative Competence in plurilingual environments, stressing the relationship between questioning and the process of developing discovery skills in Romance chat-rooms. Focusing specifically on episodes beginning with intercultural questioning, we will analyse: (1)…

  20. Mobile Library Guidelines. IFLA Professional Report No. 28 [and] Lineamientos sobre Bibliotecas Moviles. Informes Professionales de IFLA: 30.

    ERIC Educational Resources Information Center

    Pestell, Robert

    This publication provides the latest information available on the equipment and operation of mobile libraries operating out of road vehicles. The guide provides details on the establishment of mobile library services, financing, vehicles, furniture and equipment, staffing, collections, service base, and publicity. Some generalizations with regard…

  1. General Information about Learning Disabilities (Fact Sheet Number 7) = Informacion General sobre Impedimentos en el Aprendizaje (Fact Sheet Number 19).

    ERIC Educational Resources Information Center

    Interstate Research Associates, Inc., Washington, DC.

    This fact sheet providing general information about learning disabilities is presented in both English and Spanish versions. It begins with the federal definition of learning disabilities and a discussion of its implications followed by estimates of incidence. Typical characteristics of students with learning disabilities are then summarized as…

  2. Lengua Viva: Un programa de television sobre el habla espontanea (Living Language: A Television Program on Spontaneous Speech)

    ERIC Educational Resources Information Center

    Criado de Val, Manuel

    1975-01-01

    A program shown on Spanish television is a linguistic survey of Spain. Spontaneous conversations were filmed and taped in all regions of the country. It is evident that the mass media are spreading a standard form of speech and that regional differences are becoming blurred. (Text is in Spanish.) (CHK)

  3. Personal Safety for Children: A Guide for Parents = Una guia para los padres sobre la seguridad personal de los ninos.

    ERIC Educational Resources Information Center

    Department of Justice, Washington, DC.

    Noting that parents and teachers have the responsibility of safeguarding children and teaching them the skills they need to be safe, this pamphlet, in Spanish and English versions, is designed to help parents talk to their children about how to protect themselves against abduction and exploitation. The pamphlet is organized into six sections.…

  4. Estudio numerico y experimental del proceso de soldeo MIG sobre la aleacion 6063--T5 utilizando el metodo de Taguchi

    NASA Astrophysics Data System (ADS)

    Meseguer Valdenebro, Jose Luis

    Electric arc welding processes represent one of the most used techniques on manufacturing processes of mechanical components in modern industry. The electric arc welding processes have been adapted to current needs, becoming a flexible and versatile way to manufacture. Numerical results in the welding process are validated experimentally. The main numerical methods most commonly used today are three: finite difference method, finite element method and finite volume method. The most widely used numerical method for the modeling of welded joints is the finite element method because it is well adapted to the geometric and boundary conditions in addition to the fact that there is a variety of commercial programs which use the finite element method as a calculation basis. The content of this thesis shows an experimental study of a welded joint conducted by means of the MIG welding process of aluminum alloy 6063-T5. The numerical process is validated experimentally by applying the method of finite element through the calculation program ANSYS. The experimental results in this paper are the cooling curves, the critical cooling time t4/3, the weld bead geometry, the microhardness obtained in the welded joint, and the metal heat affected zone base, process dilution, critical areas intersected between the cooling curves and the curve TTP. The numerical results obtained in this thesis are: the thermal cycle curves, which represent both the heating to maximum temperature and subsequent cooling. The critical cooling time t4/3 and thermal efficiency of the process are calculated and the bead geometry obtained experimentally is represented. The heat affected zone is obtained by differentiating the zones that are found at different temperatures, the critical areas intersected between the cooling curves and the TTP curve. In order to conclude this doctoral thesis, an optimization has been conducted by means of the Taguchi method for welding parameters in order to obtain an improvement on mechanical properties in aluminum metal joint. Los procesos de soldadura por arco electrico representan unas de las tecnicas mas utilizadas en los procesos de fabricacion de componentes mecanicos en la industria moderna. Los procesos de soldeo por arco se han adaptado a las necesidades actuales, haciendose un modo de fabricacion flexible y versatil. Los resultados obtenidos numericamente en el proceso de soldadura son validados experimentalmente. Los principales metodos numericos mas empleados en la actualidad son tres, metodo por diferencias finitas, metodos por elementos finitos y metodo por volumenes finitos. El metodo numerico mas empleado para el modelado de uniones soldadas, es el metodo por elementos finitos, debido a que presenta una buena adaptacion a las condiciones geometricas y de contorno ademas de que existe una diversidad de programas comerciales que utilizan el metodo por elementos finitos como base de calculo. Este trabajo de investigacion presenta un estudio experimental de una union soldada mediante el proceso MIG de la aleacion de aluminio 6063-T5. El metodo numerico se valida experimentalmente aplicando el metodo de los elementos finitos con el programa de calculo ANSYS. Los resultados experimentales obtenidos son: las curvas de enfriamiento, el tiempo critico de enfriamiento t4/3, geometria del cordon, microdurezas obtenidas en la union soldada, zona afectada termicamente y metal base, dilucion del proceso, areas criticas intersecadas entre las curvas de enfriamiento y la curva TTP. Los resultados numericos son: las curvas del ciclo termico, que representan tanto el calentamiento hasta alcanzar la temperatura maxima y un posterior enfriamiento. Se calculan el tiempo critico de enfriamiento t4/3, el rendimiento termico y se representa la geometria del cordon obtenida experimentalmente. La zona afectada termicamente se obtiene diferenciando las zonas que se encuentran a diferentes temperaturas, las areas criticas intersecadas entre las curvas de enfriamiento y la curva TTP. Para finalizar el trabajo de investigacion se ha realizado un

  5. Lecturas sobre educacion de adultos en America latina (Readings on Adult Education in Latin America). Serie: Retablo de Papel 14.

    ERIC Educational Resources Information Center

    Latapi, Pablo, Comp.; Castillo, Alfonso, Comp.

    Twelve essays written in Spanish on the state of adult education in Latin America are presented. The essays are organized into three main sections, including: "Concepto y evolucion historica de la educacion de adultos" (Conception and Historical Evolution of Adult Education); "Aspectos particulares" (Specific Subjects); and "Tendencias y…

  6. Apuntes sobre la distribución geográfica de Neoleucinodes elegantalis (Lepidoptera: Crambidae) en Colombia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Neoleucinodes elegantalis is considered the most limiting pest for production and merchandising of solanaceous fruit and vegetables in the Neotropics. The present study updates the geographic distribution of N. elegantalis in areas of major agricultural production of Solanum lycopersicum, S. melong...

  7. Investigación del USGS sobre el ecosistema de arrecifes de coral en el Atlántico

    USGS Publications Warehouse

    Kuffner, Ilsa B.; Yates, Kimberly K.; Zawada, David G.; Richey, Julie N.; Kellogg, Christina A.; Toth, Lauren T.; Torres-Garcia, Legna M.

    2015-01-01

    Los arrecifes de coral son estructuras sólidas, biomineralizadas que protegen comunidades costeras actuando como barreras protectoras de peligros tales como los huracanes y los tsunamis. Estos proveen arena a las playas a través de procesos naturales de erosión, fomentan la industria del turismo, las actividades recreacionales y proveen hábitats pesqueros esenciales. La conti-nua degradación mundial de ecosistemas de arrecifes de coral está bien documentada. Existe la necesidad de enfoque y organización de la ciencia para entender los procesos complejos físicos y biológicos e interacciones que están afectando el estado de los arrecifes coralinos y su capacidad para responder a un entorno cambiante.

  8. DISYUNTIVAS EN LAS CONCEPCIONES SOBRE AUTONOMÍA Y BENEFICENCIA QUE AFECTAN LA TERAPÉUTICA DEL INTENTO SUICIDA1

    PubMed Central

    Mondragón, Liliana; Monroy, Zuraya; Ito, Ma. Emily; Medina-Mora, Dra. Ma. Elena

    2010-01-01

    El objetivo del trabajo es conocer las disyuntivas entre los principios de beneficencia y autonomía, que se presentan en la relación médico-paciente, durante la terapéutica del intento de suicidio. La investigación se realizó en dos hospitales psiquiátricos de la Ciudad de México. La muestra incluyó a tres sujetos con intento de suicidio, mayores de 18 años, que eran atendidos en consulta externa a causa de una lesión autoinfligida en el último año, y a tres psiquiatras que trataban a estos pacientes. La información se obtuvo previo consentimiento informado en entrevistas individuales. Se llevó a cabo un análisis de discurso argumentado para encontrar los significados que los participantes otorgaron a los principios bioéticos y las posibles disyuntivas entre éstos. Las discordancias entre la beneficencia y la autonomía estuvieron relacionadas con el beneficio del tratamiento, el respeto por los valores y las creencias de los pacientes, entre otros. Este trabajo presenta consideraciones éticas relevantes en el escenario clínico, al ofrecer al psiquiatra un análisis bioético que le permita actuar de acuerdo con la beneficencia y respetando la autonomía del paciente frente a casos de intento de suicidio y, de esta forma procurar una mejor atención para ellos. PMID:20830214

  9. Estudio numerico y experimental del proceso de soldeo MIG sobre la aleacion 6063--T5 utilizando el metodo de Taguchi

    NASA Astrophysics Data System (ADS)

    Meseguer Valdenebro, Jose Luis

    Electric arc welding processes represent one of the most used techniques on manufacturing processes of mechanical components in modern industry. The electric arc welding processes have been adapted to current needs, becoming a flexible and versatile way to manufacture. Numerical results in the welding process are validated experimentally. The main numerical methods most commonly used today are three: finite difference method, finite element method and finite volume method. The most widely used numerical method for the modeling of welded joints is the finite element method because it is well adapted to the geometric and boundary conditions in addition to the fact that there is a variety of commercial programs which use the finite element method as a calculation basis. The content of this thesis shows an experimental study of a welded joint conducted by means of the MIG welding process of aluminum alloy 6063-T5. The numerical process is validated experimentally by applying the method of finite element through the calculation program ANSYS. The experimental results in this paper are the cooling curves, the critical cooling time t4/3, the weld bead geometry, the microhardness obtained in the welded joint, and the metal heat affected zone base, process dilution, critical areas intersected between the cooling curves and the curve TTP. The numerical results obtained in this thesis are: the thermal cycle curves, which represent both the heating to maximum temperature and subsequent cooling. The critical cooling time t4/3 and thermal efficiency of the process are calculated and the bead geometry obtained experimentally is represented. The heat affected zone is obtained by differentiating the zones that are found at different temperatures, the critical areas intersected between the cooling curves and the TTP curve. In order to conclude this doctoral thesis, an optimization has been conducted by means of the Taguchi method for welding parameters in order to obtain an improvement on mechanical properties in aluminum metal joint. Los procesos de soldadura por arco electrico representan unas de las tecnicas mas utilizadas en los procesos de fabricacion de componentes mecanicos en la industria moderna. Los procesos de soldeo por arco se han adaptado a las necesidades actuales, haciendose un modo de fabricacion flexible y versatil. Los resultados obtenidos numericamente en el proceso de soldadura son validados experimentalmente. Los principales metodos numericos mas empleados en la actualidad son tres, metodo por diferencias finitas, metodos por elementos finitos y metodo por volumenes finitos. El metodo numerico mas empleado para el modelado de uniones soldadas, es el metodo por elementos finitos, debido a que presenta una buena adaptacion a las condiciones geometricas y de contorno ademas de que existe una diversidad de programas comerciales que utilizan el metodo por elementos finitos como base de calculo. Este trabajo de investigacion presenta un estudio experimental de una union soldada mediante el proceso MIG de la aleacion de aluminio 6063-T5. El metodo numerico se valida experimentalmente aplicando el metodo de los elementos finitos con el programa de calculo ANSYS. Los resultados experimentales obtenidos son: las curvas de enfriamiento, el tiempo critico de enfriamiento t4/3, geometria del cordon, microdurezas obtenidas en la union soldada, zona afectada termicamente y metal base, dilucion del proceso, areas criticas intersecadas entre las curvas de enfriamiento y la curva TTP. Los resultados numericos son: las curvas del ciclo termico, que representan tanto el calentamiento hasta alcanzar la temperatura maxima y un posterior enfriamiento. Se calculan el tiempo critico de enfriamiento t4/3, el rendimiento termico y se representa la geometria del cordon obtenida experimentalmente. La zona afectada termicamente se obtiene diferenciando las zonas que se encuentran a diferentes temperaturas, las areas criticas intersecadas entre las curvas de enfriamiento y la curva TTP. Para finalizar el trabajo de investigacion se ha realizado una optimizacion, con la aplicacion del metodo de Taguchi, de los parametros de soldeo con el objetivo de obtener una mejora sustancial en las propiedades mecanicas de las uniones metalicas de aluminio.

  10. The ABCs of Special Education: A Handbook for Parents = El ABS Sobre Educacion Especial: Un Folleto para los Padres.

    ERIC Educational Resources Information Center

    Ewing, Preston E., Jr.; Hinton, Valeska S.

    This bilingual handbook is intended to help parents understand their rights under P.L. 94-142, the Education for All Handicapped Children Act. The following topics are addressed: the Act's legislative history, identification of special education, explanation of P.L. 94-142, parents' rights to know, student records, student testing, students'…

  11. Informe Anual a la Nación sobre el Cáncer de 1975 a 2008: preguntas y respuestas

    Cancer.gov

    Los índices generales de mortalidad por cáncer han seguido disminuyendo desde principios de los noventa entre hombres, mujeres y niños. Los índices de mortalidad disminuyeron en promedio 1,6% por año entre 2004 y 2008.

  12. Ecocardiografía tridimensional. Nuevas perspectivas sobre la caracterización de la válvula mitral

    PubMed Central

    Solis, Jorge; Sitges, Marta; Levine, Robert A.; Hung, Judy

    2010-01-01

    Recent developments in three-dimensional echocardiography have made it possible to obtain images in real time, without the need for off-line reconstruction. These developments have enabled the technique to become an important tool for both research and daily clinical practice. A substantial proportion of the studies carried out using three-dimensional echocardiography have focused on the mitral valve, the pathophysiology of mitral valve disease and, in particular, functional mitral regurgitation. The aims of this article were to review the contribution of three-dimensional echocardiography to understanding of the functional anatomy of the mitral valve and to summarize the resulting clinical applications and therapeutic implications. PMID:19232192

  13. Liv and Lucky in Liverland. . . Color Us Healthy! A Workbook about Your Liver = Un Cuaderno de trabajo sobre tu higado.

    ERIC Educational Resources Information Center

    1995

    This workbook/coloring book, on the liver and good health is designed for primary school students. The 21 line drawings illustrate different aspects of liver function, maintaining a healthy liver, and preventing liver disease. Each page is captioned in both English and Spanish. (ND)

  14. Investigation of Chitosan for Decorporation of 60Co in the Rat

    SciTech Connect

    Levitskaia, Tatiana G.; Creim, Jeffrey A.; Curry, Terry L.; Luders, Teresa; Morris, James E.; Sinkov, Sergey I.; Woodstock, Angela D.; Thrall, Karla D.

    2009-08-01

    Purpose: The reported investigation is a part of our on-going research aimed at identifying effective in vivo non-toxic decorporation agents and developing new therapies to treat internal contamination with radionuclides. The non-toxic nature of chitosan makes it an especially attractive candidate for unsupervised treatment of the general population in case of radiological/nuclear emergency. In this study, chemically unmodified water-soluble chitosan oligosaccharide of low molecular weight was tested for decorporation of cobalt-60 (Co-60) using a rodent model. Methods: Affinity of chitosan oligosaccharide for Co(II) was tested in vitro under conditions of physiological pH range and ionic strength using combined spectrophotometric and potentiometric titration techniques. Fisher F344 rat model was used for in vivo studies. To evaluate effect of chitosan on ingested Co-60, animals received single oral dose of Co-60 chloride (7 – 13.2 kBq per animal) followed by oral administration of chitosan material (288 – 366 mg per kg body weight); chitosan dosing was repeated in 24 hours. Chitosan was also tested for removal of internalized Co-60. In this study, Co-60 single intravenous injection (7 – 8 kBq per animal) was followed by repetitive oral (300 mg per kg body weight) or intravenous (195 mg per kg body weight) administration of the chitosan material once daily for 5 days. Control animal groups received a single dose of Co-60 without chelator treatment. Excreta was collected daily. Tissues were collected postmortem and analyzed for radioactivity by gamma counting technique. Results: In vitro experiments confirmed binding of Co(II) by chitosan oligosaccharide, formation of mixed cobalt-chitosan-hydroxide complex species was proposed, and stability constants was calculated. Control in vivo studies indicated that about 71% of ingested Co-60 was excreted in two days predominantly through the gastrointestinal tract. For intravenously administered Co-60, urinal excretion

  15. Cobalt-60 tomotherapy: Clinical treatment planning and phantom dose delivery studies

    SciTech Connect

    Dhanesar, Sandeep; Darko, Johnson; Joshi, Chandra P.; Kerr, Andrew; John Schreiner, L.

    2013-08-15

    Purpose: Investigations have shown that a Cobalt-60 (Co-60) radioactive source has the potential to play a role in intensity modulated radiation therapy (IMRT). In this paper, Co-60 tomotherapy's conformal dose delivery potential is evaluated by delivering conformal dose plans on a cylindrical homogeneous phantom containing clinical structures similar to those found in a typical head and neck (H and N) cancer. Also, the clinical potential of Co-60 tomotherapy is investigated by generating 2D clinical treatment plans for H and N and prostate anatomical regions. These plans are compared with the 6 MV based treatment plans for modalities such as linear accelerator-based tomotherapy and broad beam IMRT, and 15 MV based 3D conformal radiation therapy (3DCRT).Methods: For experimental validation studies, clinical and nonclinical conformal dose patterns were delivered on circular, homogeneous phantoms containing GafChromic film. For clinical planning study, dose calculations were performed with the EGSnrc Monte Carlo program, where a Theratronics 780C Co-60 unit and a 6 MV linear accelerator were modeled with a MIMiC binary multileaf collimator. An inhouse inverse treatment planning system was used to optimize tomotherapy plans using the same optimization parameters for both Co-60 and 6 MV beams. The IMRT and 3DCRT plans for the clinical cases were generated entirely in the Eclipse treatment planning system based on inhouse IMRT and 3DCRT site specific protocols.Results: The doses delivered to the homogeneous phantoms agreed with the calculations, indicating that it is possible to deliver highly conformal doses with the Co-60 unit. The dose distributions for Co-60 tomotherapy clinical plans for both clinical cases were similar to those obtained with 6 MV based tomotherapy and IMRT, and much more conformal compared to 3DCRT plans. The dose area histograms showed that the Co-60 plans achieve the dose objectives for the targets and organs at risk.Conclusions: These results

  16. Potential value of Cs-137 capsules

    SciTech Connect

    Bloomster, C.H.; Brown, D.R.; Bruno, G.A.; Hazelton, R.F.; Hendrickson, P.L.; Lezberg, A.J.; Tingey, G.L.; Wilfert, G.L.

    1985-04-01

    We determined the value of Cs-137 compared to Co-60 as a source for the irradiation of fruit (apples and cherries), pork and medical supplies. Cs-137, in the WESF capsule form, had a value of approximately $0.40/Ci as a substitute for Co-60 priced at approximately $1.00/Ci. The comparison was based on the available curies emitted from the surface of each capsule. We developed preliminary designs for fourteen irradiation facilities; seven were based on Co-60 and seven were based on Cs-137. These designs provided the basis for estimating capital and operating costs which, in turn, provided the basis for determining the value of Cs-137 relative to Co-60 in these applications. We evaluated the effect of the size of the irradiation facility on the value of Cs-137. The cost of irradiation is low compared to the value of the product. Irradiation of apples for disinfestation costs $.01 to .02 per pound. Irradiation for trichina-safe pork costs $.02 per pound. Irradiation of medical supplies for sterilization costs $.07 to .12 per pound. The cost of the irradiation source, either Co-60 or Cs-137, contributed only a minor amount to the total cost of irradiation, about 5% for the fruit and hog cases and about 20% for the medical supply cases. We analyzed the sensitivity of the irradiation costs and Cs-137 value to several key assumptions.

  17. 40 CFR Appendix E to Part 61 - Compliance Procedures Methods for Determining Compliance With Subpart I

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... determining compliance with 40 CFR part 61, subpart I. The procedures consist of a series of increasingly more... in “Background Information Document: Procedures Approved for Demonstrating Compliance with 40 CFR...+02 1.7E+05 Co-60 1.6E−05 1.6E−02 1.6E+01 Co-60m 4.0E+00 4.0E+03 4.0E+06 Co-61 3.8E+00 3.8E+03...

  18. 40 CFR Appendix E to Part 61 - Compliance Procedures Methods for Determining Compliance With Subpart I

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... determining compliance with 40 CFR part 61, subpart I. The procedures consist of a series of increasingly more... in “Background Information Document: Procedures Approved for Demonstrating Compliance with 40 CFR...+02 1.7E+05 Co-60 1.6E−05 1.6E−02 1.6E+01 Co-60m 4.0E+00 4.0E+03 4.0E+06 Co-61 3.8E+00 3.8E+03...

  19. 40 CFR Appendix E to Part 61 - Compliance Procedures Methods for Determining Compliance With Subpart I

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... determining compliance with 40 CFR part 61, subpart I. The procedures consist of a series of increasingly more... in “Background Information Document: Procedures Approved for Demonstrating Compliance with 40 CFR...+02 1.7E+05 Co-60 1.6E−05 1.6E−02 1.6E+01 Co-60m 4.0E+00 4.0E+03 4.0E+06 Co-61 3.8E+00 3.8E+03...

  20. A comparison of radiation damage in liner ICs from cobalt-60 gamma rays and 2.2-MeV electrons

    NASA Technical Reports Server (NTRS)

    Gauthier, M. K.; Nichols, D. K.

    1983-01-01

    The total ionizing dose response of fourteen IC types from eight manufacturers was measured using Co-60 gamma rays and 2.2-MeV electrons for exposure levels of 100 to 20,000 Gy(Si). Key parameter measurements were made and compared for each device type. The data show that a Co-60 source is not a suitable simulation source for some systems because of the generally more damaging nature of electrons as well as the unpredictable nature of the individual device response to the two types of radiations used here.

  1. A comparison of radiation damage in linear ICs from Cobalt-60 gamma rays and 2.2 MeV electrons

    NASA Technical Reports Server (NTRS)

    Gauthier, M. K.; Nichols, D. K.

    1983-01-01

    The total ionizing dose response of fourteen IC types from eight manufacturers have been measured using Co-60 gamma rays and 2.2 MeV electrons for exposure levels of 100 to 20,000 Gy(Si). Key parameter measurements were made and compared for each device type. The data show that a Co-60 source may not be a suitable simulation source for some systems, because of the generally more damaging nature of electrons as well as the unpredictable nature of the individual device response to the two types of radiations used here.

  2. Consistency in reference radiotherapy dosimetry: resolution of an apparent conundrum when 60Co is the reference quality for charged-particle and photon beams

    NASA Astrophysics Data System (ADS)

    Andreo, Pedro; Wulff, Jörg; Burns, David T.; Palmans, Hugo

    2013-10-01

    Substantial changes in ion chamber perturbation correction factors in 60Co γ-rays, suggested by recent Monte Carlo (MC) calculations, would cause a decrease of about 1.5% in the reference dosimetry of all types of charged particles (electrons, protons and heavier ions) based on calculated kQ values. It has gone largely unnoticed that the ratio of calibration coefficients ND, w, Co60 and NK, air, Co60 yields an experimental value of Fch, Co60 = (sw-air pch)Co60 through ND, air, Co60. Coefficients provided by the IAEA and traceable to the BIPM for 91 NE-2571 chambers result in an average Fch, Co60 which is compared with published (and new) MC simulations and with the value in IAEA TRS-398. It is shown that TRS-398 agrees within 0.12% with the experimental Fch, Co60. The 1.5% difference resulting from MC calculations (1.1% for the new simulations) cannot be justified using current fundamental data and BIPM standards if consistency in the entire dosimetry chain is sought. For photons, MC kQ factors are compared with TRS-398. Using the same uncertainty for Wair, the two sets of data overlap considerably. Experimental kQ values from standards laboratories lie between the two sets of calculated values, showing no preference for one set over the other. Observed chamber-to-chamber differences, that include the effect of waterproof sleeves (also seen for 60Co), justify the recommendation in TRS-398 for kQ values specifically measured for the user chamber. Current developments on I-values for the stopping powers of water and graphite are presented. A weighted average Iwater = 78 ± 2 eV is obtained from published experimental and DRF-based values; this would decrease sw-air for all types of radiotherapy beams between 0.3% and 0.6%, and would consequently decrease the MC derived Fch, Co60. The implications of a recent proposal for Igraphite = 81 eV are analysed, resulting in a potential decrease of 0.7% in NK, air, Co60 which would raise the experimental Fch, Co60

  3. Desarrollo de un instrumento para medir percepciones sobre el contexto de construccion del conocimiento cientifico de estudiantes universitarios de nuevo ingreso

    NASA Astrophysics Data System (ADS)

    Garcia-Ramirez, Jaime Antonio

    En esta investigacion, se desarrollo un instrumento que permite medir percepciones relacionadas al contexto de constriccion del conocimiento cientifico. Se examinaron instrumentos existentes y se encontro que el VOSTS (Views on science, technology, and society), instrumento desarrollado empiricamente en Canada por Aikenhead, Ryan y Fleming, podia traducirse y validarse en el contexto cultural puertorriqueno. El instrumento es extenso, consta de 113 reactivos, cada uno con una premisa basica relacionada a la tematica ciencia, tecnologia y sociedad y un numero de alternativas relacionadas a la premisa que oscila entre siete y trece. Se delimito su utilizacion a los quince reactivos identificados por los autores como relacionados a la construccion social del conocimiento cientifico. Metodologicamente, se procedio a utilizar el modelo de adaptacion intercultural, que permite que el instrumento desarrollado satisfaga las dimensiones de equivalencia semantica, de contenido, tecnica, de criterio y conceptual, atemperado asi al instrumento original. Se cumplio con este proposito mediante la traduccion de la version original en ingles al espanol y viceversa. Se utilizaron comites para examinar la traduccion y la retro-traduccion del instrumento. Se realizo una prueba piloto con estudiantes universitarios de nuevo ingreso, utilizando el instrumento traducido para asegurar su intelegibilidad. La confiabilidad del instrumento se determino mediante la intervencion de un panel de expertos quienes clasificaron las distintas posiciones dentro de cada reactivo en: realista, con merito e ingenua; se transformaron estas opciones en valores numericos lo que permitio establecer una escala Likert para cada una. Se suministro el instrumento a una muestra de estudiantes universitarios de nuevo ingreso con caracteristicas similares a las de la poblacion puertorriquena en cuanto a ejecucion en las pruebas de aptitud verbal y matematica del College Board. Los resultados de sus contestaciones fueron transformados numericamente para poder obtener el coeficiente de correlacion de Spearman-Brown para el instrumento (0.661, p < 0.01). El analisis de las contestaciones de los estudiantes refleja percepciones diversas y, en algunos casos, contradictorias con respecto al contexto de construccion del conocimiento cientifico.

  4. Perspectivas sobre las escuelas charter: Una resena para padres de familia (Perspectives on Charter Schools: A Review for Parents). ERIC Digest.

    ERIC Educational Resources Information Center

    Donahoo, Saran

    Recently, charter schools have gained popularity with parents, students, and others as alternatives to public schools, but what are charter schools and what effects are they having? This Spanish-language Digest defines charter schools and clarifies some of the administrative and legal details surrounding such schools. The Digest also lays out some…

  5. Feedback Cheerleader, Mean-Spirited Feedback Estudio Critico Discursivo De Ideologias Sobre El Feedback Escrito En Un Departamento Universitario De Espanol En Estados Unidos

    ERIC Educational Resources Information Center

    Dominguez-Mujica, Maria Eugenia

    2012-01-01

    The aim of this research is to investigate ideologies that monitor and control styles of written feedback as well as discursive resources used in the expression of those ideologies. Using socio-cognitive analysis, a development of critical discourse studies, I have analyzed 44 sessions of chat on the Internet, 78 journal notes, 31 emails and 12…

  6. Producción masiva automatizada de la broca del café, Hypothenemus hampei (Coleoptera: Scolytidae) sobre la dieta artificial Cenibroca modificada.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An automated system for the mass rearing of coffee berry borer, CBB, Hypothenemus hampei (Ferrari) was developed at the National Biological Control Laboratory, USDA-ARS in the United States. A novel cell design of 32 cell trays (30 x 14.6 x 1.1 cm) and an automated diet dispenser were developed and ...

  7. La influencia del medio interestelar sobre la evolución del remanente de supernova (RSN) G53.6-2.2

    NASA Astrophysics Data System (ADS)

    Giacani, E. B.; Dubner, G.; Cappa, C.; Testori, J. C.

    G53.6-2.2 is a supernova remnant with an unusual morphology: in the radio band the overall shape can be described as two shells that overlap on the NW side of the remnant. The X-ray emission fills the source and peaks in the region where the radio rings overlap; while in the optical range the emission consists of filaments that correlate with portions of radio rings that overlap in the NW. The aim of the present project is to investigate the neutral hydrogen distribution around the remnant in search for signatures that allow to disclose the role of the surrounding gas in conditioning the observed morphology.

  8. Uso de los Datos de Biomonitoreo para Informar sobre la Evaluacion Infantil (American translation is: USING BIOMONITORING DATA TO INFORM EXPOSURE ASSESSMENT IN CHILDREN)

    EPA Science Inventory

    Discussing the challenges associated with estimating and interpreting toxicant exposures and health risks from biomonitoring data. This extended abstract was translated in Spanish and published in Acta Toxicologica Argentina.

  9. "Que vienen los lobos!" (Breve nota sobre el plural de los apellidos) ("May The Wolves Come:" [A Brief Note on the Plural of Surnames])

    ERIC Educational Resources Information Center

    Vivaldi, Gonzalo Martin

    1975-01-01

    This article discusses the problems that arise with the formation of plural forms of surnames in Spanish, problems both with morphology and with ambiguity. Suggestions as to how to lessen problems are made. (Text is in Spanish.) (CLK)

  10. Politica Nacional sobre Discapacidad: Un Informe del Progreso, Diciembre 2000-Diciembre 2001 (National Disability Policy: A Progress Report, December 2000-December 2001).

    ERIC Educational Resources Information Center

    National Council on Disability, Washington, DC.

    This report (written in Spanish) of the National Council on Disability (NCD) describes the nation's progress in advancing public policies to increase the inclusion, empowerment, and independence of people with disabilities in light of the Americans with Disabilities Act of 1990. The report covers December 2000 through December 2001. It reviews…

  11. Steppin' On Up: A Post-Secondary Guide for Migrant Students = Tomando Accion: Una Guia para los Estudiantes Migrantes Sobre Que Hacer Despues de la Escuela Secundaria.

    ERIC Educational Resources Information Center

    Western Stream Migrant Education Program Coordination Center, Portland, OR.

    This bilingual guide (English and Spanish) provides information for migrant students on postsecondary education. The guide includes information on: (1) career planning, involving self-exploration, occupational exploration, and strategies for reaching career objectives; (2) planning for postsecondary education during high school, including a…

  12. International Work Group for Indigenous Affairs Newsletter, July 1991-December 1992 = Boletin de Grupo Internacional de Trabajo sobre Asuntos Indigenas, Septiembre 1991-Diciembre 1992.

    ERIC Educational Resources Information Center

    IWGIA Newsletter, 1992

    1992-01-01

    This document contains seven consecutive English-language issues of the IWGIA Newsletter, from July 1991 through December 1992, followed by the seven corresponding issues in Spanish. These newsletters provide educators with a resource on the history, current conditions, and struggles for self-determination of indigenous peoples around the world.…

  13. Television Viewing = Lo que los padres de estudiantes dotados necesitan saber sobre ver...television. What Parents of Gifted Students Need To Know about...Series.

    ERIC Educational Resources Information Center

    Siegle, Del, Ed.

    This booklet (Practitioner's Guide), in both an English version and a Spanish version, is intended to help parents apply the findings of research to parental mediation of television viewing by their children, including gifted children. Research facts are briefly summarized and implications for the home are drawn. Suggestions for parents are…

  14. Manual sobre la Educacion en California para Padres de Idiomas Minoritarios = A Handbook on California Education for Language Minority Parents--Spanish/English Edition.

    ERIC Educational Resources Information Center

    California State Dept. of Education, Sacramento. Bilingual Education Office.

    This bilingual handbook, presented in both Spanish and English, is designed to assist parents of language minority students who are residing in California. The book is part of the technical assistance effort of the State Department of Education to clarify the operations of the California schools to language minority parents so they can better…

  15. Manual sobre la Educacion en California para Padres de Idiomas Minoritarios (A Handbook on California Education for Language Minority Parents). Revised Edition. Spanish/English Edition.

    ERIC Educational Resources Information Center

    California State Dept. of Education, Sacramento. Office of Bilingual Bicultural Education.

    The handbook, an update of the 1986 handbook, is designed for Spanish-speaking parents of California public school students, and answers commonly-asked questions about the state public education system and its services, particularly those of interest to this population. Information is presented in both Spanish-and English-language sections, in a…

  16. Sobre la convertibilidad de ciertos adjectivos en adverbios en el idioma espanol (Concerning the Convertibility of Some Spanish Adjectives into Adverbs).

    ERIC Educational Resources Information Center

    Zierer, Ernesto

    1971-01-01

    This paper considers Spanish adjectives and the possibility of converting some adjectives into adverbs, keeping the same general significance of a sentence. The conversion of an adjective into an adverb under these circumstances can be accomplished through a transformation which can be applied to a particular logical-semantic structure. The author…

  17. La investigacion sobre la calidad de los programas para ninos de hasta dos anos de edad (Research on Quality in Infant-Toddler Programs). ERIC Digest.

    ERIC Educational Resources Information Center

    Honig, Alice Sterling

    Concern about the quality of infant-toddler care programs has grown recently in response to two factors. The first is the need of employed parents for such care, and the second is research emphasizing the importance of brain development in the early years. This Spanish-language Digest introduces some of the many issues related to the quality of…

  18. Tax and Record Keeping Information for Family Child Care = Informacion Sobre los Impuestos y la Documentacion para el Cuidado Infantil en el Hogar.

    ERIC Educational Resources Information Center

    Gellert, Sandra

    This pamphlet from the Children's Foundation, in both English- and Spanish-language versions, provides advice to child care providers on record-keeping methods. The pamphlet also gives definitions and guidance on business expenses (100% deductible, shared personal and business, and depreciated capital expenses), time-space formula, self-employment…

  19. Parenting Information for Parents: Books 1-3 (Informacion Para Los Padres Sobre La Crianza De Los Hijos: Libros 1-3).

    ERIC Educational Resources Information Center

    Moreno, Steve

    These 3 booklets provide ideas, guidelines, and activities for establishing effective parenting and are part of a series of 22 booklets specifically designed to help parents understand their children and help them to learn. The first booklet (booklet #20) discusses preparation for parenthood, infant and toddler developmental stages, the importance…

  20. Kathy Finds Out about the Introduction of Solids. Mother-to-Mother Support = Josefa Descubre Conocimientos sobre la Introduccion de Solidos. Apoyo Madre a Madre.

    ERIC Educational Resources Information Center

    Magalhaes, Rebecca; Stone-Jimenez, Maryanne; Allen de Smith, Paulina; Smith, Natalia

    These magazine-sized booklets, one in English, one in Spanish, are in cartoon format and are designed to be used by people with limited literacy in English or Spanish. This booklet explains that exclusive breastfeeding means giving no water, liquids, or food; breast milk contains sufficient water to satisfy the baby's thirst; at about 6 months,…

  1. Guia para la Ensenanza Combinada de Ingles y Ciencia. Para Padres/sobre Padres. (A Guide to Teaching English and Science Together. For Parents/about Parents).

    ERIC Educational Resources Information Center

    Schwartz, Wendy

    In the past, students who knew only a little English (called limited English proficient, or LEP), were usually taught only low-level science and mathematics. Now, new science and mathematics teaching methods can help LEP students get a good education in both fields. This guide will help parents know if their children are learning as much as…

  2. Sobre la naturaleza de cinco candidatos a cúmulos abiertos ubicados próximos a la dirección del centro galáctico

    NASA Astrophysics Data System (ADS)

    Piatti, A. E.; Clariá, J. J.

    CCD BVI Johnson-Cousins observations obtained for 1759 stars in 4'×4' regions around the unstudied southern stellar aggregates Ruprecht 103, 124, 129, 146 and 166 are presented. The objects are described as open clusters in the catalogues of star clusters and associations of Alter et al. (1970) and LyngÅ (1987), as well as, in the ESO/Uppsala Survey of the ESO (B) Atlas (Lauberts 1982). Our analysis shows that none of these objects are genuine open clusters, except perhaps Ruprecht 166, since no clear main sequences (MSs) or other meaningful features can be seen in the extracted (V,B-V) and (V,V-I) colour-magnitude diagrams (CMDs). The star sequences seen in the distinct CMDs, specially for Ruprecht 124 and 129, are apparently formed by the superimposition of MS field stars affected by varying amounts of interstellar absorption and/or placed at different distances from the Sun. The CMDs of Ruprecht 166 present a pronounced variation in the luminosity function along the apparent MS, a fact from which we can infer the notion of these stars had a different origin. Star counts carried out within and outside the cluster candidate fields not only support the results that the objects do not present a significant number density contrast with respect to the Galactic disk, but also show that they do not appear to be candidate late stages of star cluster dynamical evolution. Several other stellar aggregates included in open cluster catalogues have previously been disproved as genuine physical systems (see, e.g., Carraro & Patat 1995, MNRAS, 276, 563; Carraro 2000, A&A, 357, 145; Piatti & Clariá 2001, A&A, 370, 931). Thus, the present work implies the potential likelihood of other wrongly classified open clusters.

  3. How To Talk to Your Teens and Children about AIDS = Como hablar con sus adolescentes y sus ninos sobre el SIDA.

    ERIC Educational Resources Information Center

    National PTA, Chicago, IL.

    Two brochures, one in English and one in Spanish, provide parents with basic information that will enable them to educate their children about Acquired Immune Deficiency Syndrome (AIDS). Contents address 11 questions: (1) What is AIDS? (2) How do you get AIDS? (3) How is AIDS not spread? (4) Who can get AIDS? (5) How can you tell if someone has…

  4. Producción masiva automatizada de la broca del café Hypothenemus hampei Ferrari (Coleóptera: Scolytidae) y de sus parasitoides sobre dietas artificiales

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This article reviews the current state of knowledge concerning the mass rearing system of the coffee berry borer, cbb, Hypothenemus hampei (Ferrari) (Coleoptera: Scolytidae), and its African parasitoids: the ectoparasitoids Cephalonomia stephanoderis (Betrem) and Prorops nasuta ((Waterston) (Hymenop...

  5. Simposio sobre Educacion de Ninas: Evidencias, Temas, Acciones. Actas de sesiones. (Symposium on Girls Education: Evidence, Issues, Actions. Proceedings). (Washington, DC, May 17-18, 2000).

    ERIC Educational Resources Information Center

    Agency for International Development (IDCA), Washington, DC.

    This symposium highlighted core issues of controversy in girls' education and developed implications for policy and practice. Its evidence-based discussion forum encouraged dialogue, debate, and increased interaction and developed partnerships among academic institutions, nongovernmental organizations, multilateral development agencies, and other…

  6. Tips for Parents on Keeping Children Drug Free = Consejos para Los Padres Sobre Como Mantener a Los Hijos Libres de La Droga.

    ERIC Educational Resources Information Center

    Department of Education, Washington, DC. Office of Intergovernmental and Interagency Affairs.

    Research shows that recent trends in youth drug use have stabilized; however, the rates of use remain at high levels. It has been shown that the earlier drug use is initiated, the more likely a person is to develop drug problems later in life. Youth substance abuse may lead to many other problems that affect not only the child, but also the…

  7. Resultados de una encuesta sobre posibles reformas ortograficas en el espanol del siglo XX (Results of a Survey Concerning Possible Orthographic Reforms in Twentieth Century Spanish)

    ERIC Educational Resources Information Center

    Varela Cuellar, Beatriz

    1976-01-01

    This article presents the results of a questionnaire sent to Spanish teachers regarding possible orthographic reforms in Spanish. Changes considered included elimination of certain letters and representation of each phoneme by only one letter. Responses to each question are classified and explained. (Text is in Spanish.) (CHK)

  8. Consideraciones sobre la investigacion hermeneutica en la educacion en lenguas y culturas extranjeras (Aspects of Applying a Hermeneutic Approach to Foreign Language and Culture Education).

    ERIC Educational Resources Information Center

    Zoreda, Margaret Lee

    Drawing on writings by recent post-modernist thinkers and semioticians, this paper focuses on a combination of hermeneutic and semiotic viewpoints and applies them to defining the nature of interpretation in an educational setting (e.g., text interpretation), the interpreter, and the essence of the act of comprehension and interpretation. The main…

  9. The Portugal Project: Adult Education in a Socio-economic Perspective. Paper for the Course, "Curso sobre Educacao de Adultos." Document No. 1.

    ERIC Educational Resources Information Center

    Erasmie, Thord

    Education is one of the major problems connected with the economic and social distribution of the total resources of the world. Examples of the educational gap between rich and poor countries can be seen by statistical comparisons between Peru and Czechoslavakia and between Guatemala and Denmark which show how unevenly educational resources are…

  10. Conservación de material histórico sobre papel en el Observatorio Astronómico de la Universidad Nacional de Córdoba

    NASA Astrophysics Data System (ADS)

    Laguzzi, N.; Tonini, A.; Andreoli, G.; Goldes, G.; Paolantonio, S.; Cequeira, F.; Landi, L.; Alba, J.

    At the recently created Astronomical Museum ``Pte. Sarmiento - Dr. Benjamin Gould", the task of preventive conservation of historic documents has been faced. These materials include: 1) letters exchanged between national authorities and the directors of the Observatory, during the first decades (1870-1880-1890); b) original observation logs from these very first times, containing astrometrical and photometrical data; c) a variety of ancient books and papers; d) administrative documents. The state of conservation of this patrimony was varied: since well-conserved books and letters, to highly degraded logs. The observation logs written by B. Gould and the astronomers who followed him had been stocked in a safe with a permanent humidity of about 70 %, without any ventilation and exposed to the attack of insects of the family ``dermestidae." These conditions could not be worse for the conservation of paper. In order to stop the proccess of degradation and create a healthy environment for written-paper conservation, a team was formed with personnel belonging to the Cultural Area of the Municipality. The tasks being performed on the observation logs are: 1) an initial, mechanical cleaning, performed once the material is extracted from the contaminated safe: by these means, adult insects and pupas are removed 2) a stage of about two weeks of duration, in which the logs are mantained in a vacuum chamber, in orden to completely eliminate the adult, pupa and egg stage insects by anoxia 3) the final mechanical cleaning 4) storage in a clean location. In order to perform these tasks, we work in collaboration with the Environmental Observatory of the City, and the group of Material-Science Research of Fa.M.A.F. Regarding the letters, a mechanical cleaning was performed. After that, the letters were digitized by means of a scanner, inventoried, put inside acid-free polipropylene envelops and filed for conservation, protected from intense light and external sources of contamination. Copies of these letters will be included as exhibits.

  11. Catalysts for Change: Three Case Studies of Quality Education Worldwide = Catalizadores del Cambio: Tres Casos de Estudio sobre la Educacion de Calidad en el Mundo

    ERIC Educational Resources Information Center

    Puriefoy, Wendy D.

    2007-01-01

    Public education is the cornerstone of democracy and is absolutely fundamental to a democratic, civil and prosperous society. Beyond the boundaries of the United States, other countries are working to provide quality education to their children through civil society institutions. In particular, there are three extraordinary organizations in Peru,…

  12. Teorí­as de primer y segundo orden sobre el potencial de ciertas figuras de equilibrio de cuerpos celestes

    NASA Astrophysics Data System (ADS)

    Gumbau, Manuel Forner

    2010-11-01

    Uno de los problemas que aborda la Mecánica Celeste es la determinación de las figuras de equilibrio de los cuerpos celestes. Para investigar su solución mediante métodos directos, se precisa evaluar el potencial generado por su autogravitación, el generado por su fuerza centrí­fuga y el generado por la fuerza de atracción entre los cuerpos. Los métodos clásicos de Finlay y Kopal que afrontan estos problemas, para determinar el potencial autogravitatorio en las configuraciones de equilibrio, emplean desarrollos en serie de los potenciales interior y exterior del potencial autogravitatorio. Estos métodos incurren en el error de suponer la convergencia en capas donde resulta cuestionable dicha convergencia para estos desarrollos en serie. En este trabajo se han elaborado unos algoritmos que contemplan toda la casuí&stica y que permiten una manipulación efic iente del producto de polinomios de Legendre, del producto de funciones asociada s de Legendre y del producto de armónicos esféricos como combinacióon lineal de ellos mismos, respectivamente. Se han obtenido, para primer y segundo orden en las amplitudes, los desarrollos correctos para los potencial es interior y exterior del potencial autogravitatorio para configuraciones de equilibrio aisladas, y , en primer orden de amplitudes, los mismos potenciales para los sistemas binarios próximos. Se ha elaborado un método analítico, en primer orden respecto de las amplitudes, para la determinación del potencial de marea en sistemas binarios próximos en el cual se manifiesta la forma de la componente secundaria del sistema

  13. Etnografía acelerada para transformar normas sociales sobre género y sexualidad en hombres puertorriqueños heterosexuales1,2

    PubMed Central

    Ortiz-Torres, Blanca; Rivera-Ortiz, Rafael J.; Mendoza, Sigrid

    2014-01-01

    Resumen La construcción de roles de género dominantes contribuyen al riesgo de contraer VIH, y por tal razón se ha urgido a que se integren las normas sociales relativas al género en las intervenciones preventivas del VIH. Este estudio pretende adaptar y desarrollar una intervención que facilite la transformación de normas sociales del género y de prácticas sexuales en hombres puertorriqueños. La intervención propone transformar normas sociales relacionadas al género y sexualidad en barras comunitarias utilizando el modelo de líderes de opinión. Luego de ser elegidos/as, los/as líderes de opinión diseminan mensajes integrando la importancia de relaciones equitativas entre parejas para la prevención del VIH. La primera fase de esta intervención es discutida en este artículo, la cual incluye un proceso de etnografía acelerada para identificar los escenarios comunitarios en los que podemos desarrollar esta intervención y permitirnos entender la cultura de las barras comunitarias. A partir de las observaciones etnográficas, pudimos: desarrollar un protocolo de seguridad para realizar las observaciones, desarrollar un perfil de la cultura de las barras, elegir las barras a participar en las dos condiciones del estudio y adaptar los instrumentos de la intervención para que respondieran a la particularidad de los/as participantes. PMID:25530828

  14. Que Sucede? Manual Informativo Sobre Rehabilitacion y Educacion Especial en Costa Rica (What's Happening? Informative Manual on Rehabilitation and Special Education in Costa Rica).

    ERIC Educational Resources Information Center

    de Mezerville, Gaston; And Others

    The manual, in Spanish, provides descriptions of rehabilitation, medical, and special education services; centers and institutions which offer physical and mental rehabilitation services; and lists of professionals and advocacy organizations in Costa Rica. Part 1 includes an overview of rehabilitation and special education, a short history of…

  15. Conversacion sobre "Tres tristes tigres". Una entrevista de Rita Guibert (A Conversation about "Three Sad Tigers". An Interview with Rita Guibert)

    ERIC Educational Resources Information Center

    Cabrera Infante, Guillermo

    1971-01-01

    Interview took place in London, England, on October 5, 1970 between Cuban writer Guillermo Cabrera Infante and journalist Rita Guibert. Special issue dedicated to contemporary Spanish American literature. (DS)

  16. Ahorre Energía: Consejos sobre el ahorro de dinero y energía en el hogar (Spanish Brochure), Energy Savers Guide

    SciTech Connect

    2014-09-01

    La versión en castellano de la guía del Departamento de Energía de los Estados Unidos que ayuda a consumidores a ahorrar energía y dinero en el hogar y en las carreteras. The Spanish-language version of U.S. Department of Energy's consumer guide to saving energy and money at home and on the road.

  17. The Dyslexia Handbook: Procedures Concerning Dyslexia and Related Disorders = Manual sobre la dislexia: Procedimientos relacionados con la dislexia y otros desordenes.

    ERIC Educational Resources Information Center

    Texas Education Agency, Austin.

    This handbook, available in English and Spanish, contains the Texas State Board of Education's approved procedures concerning dyslexia and related disorders and information regarding the state's dyslexia statutes and their relation to the federal Rehabilitation Act of 1973, Section 504, and the Individuals with Disabilities Education Act. Chapters…

  18. Guia para Madres y Padres de Familia sobre Educacion Pre-Escolar a Temprana Edad (A Parents' Guide to Early Childhood Education).

    ERIC Educational Resources Information Center

    Dodge, Diane Trister; Phinney, Joanna

    This booklet for parents explains what children learn in preschools that employ the Creative Curriculum for Early Childhood and the ways in which learning can be reinforced at home. The first sections of the booklet explain the goals and philosophy of experience-based preschools. Goals include teaching children to love reading and school and to be…

  19. A+chieving Excellence. A Parent's Guide to Site-Based Decision Making. Noteworthy = A+lcanzar la Excelencia. Un manual para padres sobre como hacer decisiones. Notable.

    ERIC Educational Resources Information Center

    Hutchins, C. L.

    The parents' guide in English and Spanish versions, offers a synthesis of the Mid-Continent Regional Educational Laboratory's (McRel) "A+chieving Excellence," a 480-page manual on educational decision-making and management. Four sections examine four broad areas in which policies must be established for improving student achievement--efficiency,…

  20. A Parent's Guide to Infant/Toddler Programs = Guia para los padres sobre los programas de cuidado infantil de 0-3 anos.

    ERIC Educational Resources Information Center

    Dodge, Diane Trister; Dombro, Amy Laura; Colker, Laura J.

    Information on how warm and responsive care can help shape infants' and toddlers' development and their ability to learn can be reassuring for concerned parents. This guide, in English and Spanish versions, presents quality child care as a partnership between the child caregiver and the parents with the primary goal of benefiting the child. The…

  1. Pick and Choose: A Videotape Series on Nutrition for Migrant Families (Coja y Escoja: Peliculas para Television Sobre la Nutricion para las Familias Migratorias).

    ERIC Educational Resources Information Center

    1979

    One of the major problems faced by migrant workers throughout the United States is a lack of awareness of the relationship between proper diet and an individual's general health and well being. To help solve this problem was the major objective of the series "Pick and Choose." The three 15-minute programs in the series present information related…

  2. Borrowing Basics. FDIC Money Smart Financial Education Curriculum = Conceptos Basicos sobre Prestamos. FDIC Money Smart Plan de Educacion para Capacitacion en Finanzas.

    ERIC Educational Resources Information Center

    Federal Deposit Insurance Corp., Washington, DC.

    This module, an introduction to credit, is one of ten in the Money Smart curriculum, and includes an instructor guide and a take-home guide. It was developed to help adults outside the financial mainstream enhance their money skills and create positive banking relationships. It is designed to enable participants to decide when and how to use…

  3. Check It Out. FDIC Money Smart Financial Education Curriculum = Conceptos Basicos sobre Cuentas Corientes. FDIC Money Smart Plan de Educacion para Capacitacion en Finanzas.

    ERIC Educational Resources Information Center

    Federal Deposit Insurance Corp., Washington, DC.

    This module on how to choose and keep a checking account is one of ten in the Money Smart curriculum, and includes an instructor guide and a take-home guide. It was developed to help adults outside the financial mainstream enhance their money skills and create positive banking relationships. It is designed to enable participants to open and keep a…

  4. 10 CFR 61.55 - Waste classification.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 700 (1) (1) H-3 40 (1) (1) Co-60 700 (1) (1) Ni-63 3.5 70 700 Ni-63 in activated metal 35 700 7000 Sr... disposed of in a geologic repository as defined in part 60 or 63 of this chapter unless proposals...

  5. 10 CFR Appendix L to Part 110 - Illustrative List of Byproduct Materials Under NRC Export/Import Licensing Authority a

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 38 (Cl 38) Chromium 51 (Cr 51) Cobalt 57 (Co 57) Cobalt 58m (Co 58m) Cobalt 58 (Co 58) Cobalt 60 (Co 60) Copper 64 (Cu 64) Curium 240 (Cm 240) Curium 241 (Cm 241) Curium 242 (Cm 242) Curium 243 (Cm...

  6. 10 CFR 30.71 - Schedule B.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...) 10 Chlorine 38 (Cl 38) 10 Chromium 51 (Cr 51) 1,000 Cobalt 57 (Co 57) 100 Cobalt 58m (Co 58m) 10 Cobalt 58 (Co 58) 10 Cobalt 60 (Co 60) 1 Copper 64 (Cu 64) 100 Dysprosium 165 (Dy 165) 10 Dysprosium...

  7. 10 CFR 30.71 - Schedule B.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...) 10 Chlorine 38 (Cl 38) 10 Chromium 51 (Cr 51) 1,000 Cobalt 57 (Co 57) 100 Cobalt 58m (Co 58m) 10 Cobalt 58 (Co 58) 10 Cobalt 60 (Co 60) 1 Copper 64 (Cu 64) 100 Dysprosium 165 (Dy 165) 10 Dysprosium...

  8. 10 CFR Appendix L to Part 110 - Illustrative List of Byproduct Materials Under NRC Export/Import Licensing Authority a

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 137) Chlorine 36 (Cl 36) Chlorine 38 (Cl 38) Chromium 51 (Cr 51) Cobalt 58m (Co 58m) Cobalt 58 (Co 58) Cobalt 60 (Co 60) Copper 64 (Cu 64) Curium 240 (Cm 240) Curium 241 (Cm 241) Curium 242 (Cm 242)...

  9. 10 CFR 30.71 - Schedule B.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...) 10 Chlorine 38 (Cl 38) 10 Chromium 51 (Cr 51) 1,000 Cobalt 57 (Co 57) 100 Cobalt 58m (Co 58m) 10 Cobalt 58 (Co 58) 10 Cobalt 60 (Co 60) 1 Copper 64 (Cu 64) 100 Dysprosium 165 (Dy 165) 10 Dysprosium...

  10. 40 CFR 60.45Da - Alternative standards for combined nitrogen oxides (NOX) and carbon monoxide (CO).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... nitrogen oxides (NOX) and carbon monoxide (CO). 60.45Da Section 60.45Da Protection of Environment... SOURCES Standards of Performance for Electric Utility Steam Generating Units § 60.45Da Alternative standards for combined nitrogen oxides (NOX) and carbon monoxide (CO). (a) The owner or operator of...

  11. 10 CFR 61.55 - Waste classification.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 700 (1) (1) H-3 40 (1) (1) Co-60 700 (1) (1) Ni-63 3.5 70 700 Ni-63 in activated metal 35 700 7000 Sr... disposed of in a geologic repository as defined in part 60 or 63 of this chapter unless proposals...

  12. 10 CFR 61.55 - Waste classification.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 700 (1) (1) H-3 40 (1) (1) Co-60 700 (1) (1) Ni-63 3.5 70 700 Ni-63 in activated metal 35 700 7000 Sr... disposed of in a geologic repository as defined in part 60 or 63 of this chapter unless proposals...

  13. 10 CFR 61.55 - Waste classification.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 700 (1) (1) H-3 40 (1) (1) Co-60 700 (1) (1) Ni-63 3.5 70 700 Ni-63 in activated metal 35 700 7000 Sr... disposed of in a geologic repository as defined in part 60 or 63 of this chapter unless proposals...

  14. 40 CFR 60.45Da - Alternative standards for combined nitrogen oxides (NOX) and carbon monoxide (CO).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... nitrogen oxides (NOX) and carbon monoxide (CO). 60.45Da Section 60.45Da Protection of Environment... SOURCES Standards of Performance for Electric Utility Steam Generating Units § 60.45Da Alternative standards for combined nitrogen oxides (NOX) and carbon monoxide (CO). (a) The owner or operator of...

  15. 40 CFR 60.45Da - Alternative standards for combined nitrogen oxides (NOX) and carbon monoxide (CO).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... nitrogen oxides (NOX) and carbon monoxide (CO). 60.45Da Section 60.45Da Protection of Environment... SOURCES Standards of Performance for Electric Utility Steam Generating Units § 60.45Da Alternative standards for combined nitrogen oxides (NOX) and carbon monoxide (CO). (a) The owner or operator of...

  16. 10 CFR 30.71 - Schedule B.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...) 10 Chlorine 38 (Cl 38) 10 Chromium 51 (Cr 51) 1,000 Cobalt 57 (Co 57) 100 Cobalt 58m (Co 58m) 10 Cobalt 58 (Co 58) 10 Cobalt 60 (Co 60) 1 Copper 64 (Cu 64) 100 Dysprosium 165 (Dy 165) 10 Dysprosium...

  17. A comparison of radiation damage in transistors from cobalt-60 gamma rays and 2.2 MeV electrons

    NASA Technical Reports Server (NTRS)

    Nichols, D. K.; Price, W. E.; Gauthier, M. K.

    1982-01-01

    The total ionizing dose response of ten bipolar transistor types has been measured using Co-60 gamma rays and 2.2 MeV electrons from exposure levels of 750, 1500, and 3000 Gy(Si). Gain measurements were made for a range of collector-emitter voltages and collector currents.

  18. Absolute supercurrent switch in ferromagnetic/superconducting/ferromagnetic trilayers operating at T > 4.2 K

    NASA Astrophysics Data System (ADS)

    Stamopoulos, D.; Aristomenopoulou, E.; Manios, E.

    2014-09-01

    Artificial (CoO-)Co/Nb/Co trilayers (TLs) are studied by means of magnetization, transport, and magnetic force microscopy measurements. By using these TLs as a model system, we provide definite means to distinguish the exchange-fields and stray-fields based magnetoresistance effects observed in relevant Ferromagnetic/Superconducting/Ferromagnetic (FM/SC/FM) structures. Accordingly, we isolate and exclusively focus on the stray-fields version, to report a complete supercurrent switch, ΔR/Rnor ≈ 100%, achieved at operating temperature T > 4.2 K. Detailed series of Co(60 nm)/Nb(dNb)/Co(60 nm) TLs are studied, in which all crucial parameters that relate to the outer Co layers and to the Nb interlayer were systematically varied to unveil the factors that motivate and/or promote the observed effect. We propose a compact model that fairly captures the underlying physics of the Co(60 nm)/Nb(dNb)/Co(60 nm) TLs studied here and can be generalized to assist understanding of the relevant processes in every kind of FM/SC/FM TLs. The presented results and accompanying model are both provocative for basic research and attractive for the design of cryogenic devices.

  19. Using a 10-keV x-ray source for hardness assurance

    SciTech Connect

    Fleetwood, D.M.; Beegle, R.W.; Sexton, F.W.; Winokur, P.S.; Miller, S.L.; Schwank, J.R.; Jones, R.V.; McWhorter, P.J.

    1986-01-01

    It is shown that a 10 keV x-ray source can be used to predict the responses of microelectronic circuits to Co-60 irradiation. Guidelines for using an x-ray tester in a hardness assurance program for VLSI CMOS circuits are suggested. 5 refs., 2 figs., 1 tbl.

  20. Rupture Loop Annex (RLA) ion exchange vault entry and characterization

    SciTech Connect

    Ham, J.E.

    1996-01-04

    This engineering report documents the entry and characterization of the Rupture Loop Annex Ion Exchange (RLAIX) Vault located near the 309 Building`s Plutonium Recycle Test Reactor (PRTR). Twelve ion exchange columns were found in the vault. Some of which contained transuranics, Cs 137, and Co 60. The characterization information is necessary for future vault cleanout and column disposal.

  1. Chemiluminescence measurements as an identification method for gamma-irradiated foodstuffs

    NASA Astrophysics Data System (ADS)

    Bögl, W.; Heide, L.

    Samples of 19 different spices, milk powder, whole onions and frozen chicken were exposed to a Co-60 source with radiation doses up to 10 4 Gy. The subsequent reaction of the irradiated foodstuffs in a luminol solution resulted in light emission (chemiluminescence). This effect can be used as an indicator of radiation treatment.

  2. The design of a gamma-ray irradiation plant—shanghai irradiation center

    NASA Astrophysics Data System (ADS)

    Fugen, Chen; Xiangrong, Xue; Zewu, Yao

    Shanghai Irradiation Center, situated in western suburb of Shanghai, was completed in March, 1986. The intensity of Co 60 is 177 KCuries at present, and untimate loading will be 500 K Curies. The Center is designed mainly for food radiation preservation and sterilization of medical devices and tools. Its processing ability is 10 T/hr for potatoes.

  3. Magnetization reversal and enhanced tunnel magnetoresistance ratio in perpendicular magnetic tunnel junctions based on exchange spring electrodes

    NASA Astrophysics Data System (ADS)

    Wang, Yi; Yin, Xiaolu; Le Roy, D.; Jiang, Jun; Wei, H. X.; Liou, S. H.; Han, X. F.

    2013-04-01

    The [Co/Pt]n multilayer based perpendicular magnetic tunnel junction stacks with wedged Co60Fe20B20 insertions up to 2 nm, and corresponding perpendicular magnetic tunnel junctions were magnetically and electrically investigated. The focus is on the influence of CoFeB insertions in the free and reference electrodes on the overall junction magnetization reversal and magnetoresistance response. The exchange spring behavior was revealed as the Co60Fe20B20 spins canting towards the in-plane direction in the [Co/Pt]n/Co60Fe20B20 hard/soft perpendicular magnetic electrodes. The broad range thickness of wedged Co60Fe20B20 insertion enables to reveal the critical transition, in particular, from rigid coupling to exchange spring coupling. With the help of 375°C annealing under 10 kOe magnetic field, the recovery from distinct multi-domain structure to nearly single domain structure was distinctly observed in the unpatterned perpendicular magnetic tunnel junction (p-MTJ) films with CoFeB thickness tCFB≥1.5 nm. Meanwhile, for the corresponding patterned perpendicular magnetic tunnel junctions with AlOx barrier, the tunnel magnetoresistance (TMR) ratio exhibited an intense enhancement over 100%. The TMR results and spin configurations were illustrated using an exchange spring model in both magnetic electrodes. The presented study shows the benefit of using exchange spring magnetic electrodes in perpendicular magnetic tunnel junction on their performance.

  4. Assessing and improving cobalt-60 digital tomosynthesis image quality

    NASA Astrophysics Data System (ADS)

    Marsh, Matthew B.; Schreiner, L. John; Kerr, Andrew T.

    2014-03-01

    Image guidance capability is an important feature of modern radiotherapy linacs, and future cobalt-60 units will be expected to have similar capabilities. Imaging with the treatment beam is an appealing option, for reasons of simplicity and cost, but the dose needed to produce cone beam CT (CBCT) images in a Co-60 treatment beam is too high for this modality to be clinically useful. Digital tomosynthesis (DT) offers a quasi-3D image, of sufficient quality to identify bony anatomy or fiducial markers, while delivering a much lower dose than CBCT. A series of experiments were conducted on a prototype Co-60 cone beam imaging system to quantify the resolution, selectivity, geometric accuracy and contrast sensitivity of Co-60 DT. Although the resolution is severely limited by the penumbra cast by the ~2 cm diameter source, it is possible to identify high contrast objects on the order of 1 mm in width, and bony anatomy in anthropomorphic phantoms is clearly recognizable. Low contrast sensitivity down to electron density differences of 3% is obtained, for uniform features of similar thickness. The conventional shift-and-add reconstruction algorithm was compared to several variants of the Feldkamp-Davis-Kress filtered backprojection algorithm result. The Co-60 DT images were obtained with a total dose of 5 to 15 cGy each. We conclude that Co-60 radiotherapy units upgraded for modern conformal therapy could also incorporate imaging using filtered backprojection DT in the treatment beam. DT is a versatile and promising modality that would be well suited to image guidance requirements.

  5. Tomographic Imaging on a Cobalt Radiotherapy Machine

    NASA Astrophysics Data System (ADS)

    Marsh, Matthew Brendon

    Cancer is a global problem, and many people in low-income countries do not have access to the treatment options, such as radiation therapy, that are available in wealthy countries. Where radiation therapy is available, it is often delivered using older Co-60 equipment that has not been updated to modern standards. Previous research has indicated that an updated Co-60 radiation therapy machine could deliver treatments that are equivalent to those performed with modern linear accelerators. Among the key features of these modern treatments is a tightly conformal dose distribution-- the radiation dose is shaped in three dimensions to closely match the tumour, with minimal irradiation of surrounding normal tissues. Very accurate alignment of the patient in the beam is therefore necessary to avoid missing the tumour, so all modern radiotherapy machines include imaging systems to verify the patient's position before treatment. Imaging with the treatment beam is relatively cost-effective, as it avoids the need for a second radiation source and the associated control systems. The dose rate from a Co-60 therapy source, though, is more than an order of magnitude too high to use for computed tomography (CT) imaging of a patient. Digital tomosynthesis (DT), a limited-arc imaging method that can be thought of as a hybrid of CT and conventional radiography, allows some of the three-dimensional selectivity of CT but with shorter imaging times and a five- to fifteen-fold reduction in dose. In the present work, a prototype Co-60 DT imaging system was developed and characterized. A class of clinically useful Co-60 DT protocols has been identified, based on the filtered backprojection algorithm originally designed for CT, with images acquired over a relatively small arc. Parts of the reconstruction algorithm must be modified for the DT case, and a way to reduce the beam intensity will be necessary to reduce the imaging dose to acceptable levels. Some additional study is required to

  6. Comparison of the degradation effects of heavy ion, electron, and cobalt-60 irradiation in an advanced bipolar process

    NASA Technical Reports Server (NTRS)

    Zoutendyk, John A.; Goben, Charles A.; Berndt, Dale F.

    1988-01-01

    Experimental measurements are reported of the degradation effects of high-energy particles (heavy Br ions and electrons) and Co-60 gamma-rays on the current gain of minimum-geometry bipolar transistors made from an advanced process. The data clearly illustrate the total-ionizing-dose vs particle-fluence behavior of this bipolar transistor produced by an advanced process. In particular, bulk damage from Co-60 gamma rays in bipolar transistors (base transport factor degradation) and surface damage in bipolar transistors from ionizing radiation (emitter-efficiency degradation) have been observed. The true equivalence between various types of radiation for this process technology has been determined on the basis of damage from the log K1 intercepts.

  7. CRRES microelectronic test chip

    NASA Astrophysics Data System (ADS)

    Lin, Y.-S.; Buehler, M. G.; Ray, K. P.; Sokoloski, M. M.

    1991-12-01

    The JPL CRRES chip was designed and fabricated in 1985 and included in the CRRES MEP. MOSFET Matrix results show the effect of shielding on radiation-induced MOSFET threshold voltage shifts and channel mobility degradation. Shielded (middle board) MOSFETs have a threshold-voltage damage factor that is approximately three orders of magnitude smaller than would be estimated from Co-60 ground tests. Unshielded (outer board) MOSFETs have a threshold-voltage damage factor that would be estimated from Co-60 ground tests. Temperature swings as large as 23 C with a 22.5 orbit periodicity affected the MOSFET data and were removed from the data in order to reveal the radiation effects. This experiment demonstrated the feasibility of characterizing MOSFETs in a matrix, thus reducing the complexity and mass of the experiment.

  8. Surplus Facilities Management Program. Post-remedial-action survey report for SNAP-8 Experimental Reactor Facility, building 010 site, Santa Susana Field Laboratories, Rockwell International, Ventura County, California

    NASA Astrophysics Data System (ADS)

    Wynveen, R. A.; Smith, W. H.; Sholeem, C. M.; Mayes, C. B.; Justas, A. L.; Flynn, K. F.

    1984-04-01

    Based on the results of the radiological assessment the following conclusions were reached: (1) soil contaminated with the radionuclides Co(60) and Er(152)Eu of undetermined origin was detected in the southwest quadrant of the Building 010 site. Co(60) was also detected in a borehole sample taken from the area that previously held the radioactive gas hold up tanks. Uranium was detected in soil from a hole in the center of the building site and in a second hole southwest of the building site. In all cases, the radionuclide levels encountered in the soil were well below the criteria set by DOE for this site; and (2) the direct instrument readings at the surface of the site were probably the result of natural radiation (terrestrial and celestial), as well as shine from the material being stored at the nearby RMDF facility. There was no evidence that the contaminated soil under the asphalt pad contributed detectable levels to the total background readings.

  9. 10 CFR 30.70 - Schedule A-Exempt concentrations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...−3 Chromium (24) Cr 51 2×10−2 Cobalt (27) Co 57 5×10−3 Co 58 1×10−3 Co 60 5×10−4 Copper (29) Cu 64 3... Mercury (80) Hg 197m 2×10−3 Hg 197 3×10−3 Hg 203 2×10−4 Molybdenum (42) Mo 99 2×10−3 Neodymium (60) Nd...

  10. 10 CFR 30.70 - Schedule A-Exempt concentrations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...−3 Chromium (24) Cr 51 2×10−2 Cobalt (27) Co 57 5×10−3 Co 58 1×10−3 Co 60 5×10−4 Copper (29) Cu 64 3... Mercury (80) Hg 197m 2×10−3 Hg 197 3×10−3 Hg 203 2×10−4 Molybdenum (42) Mo 99 2×10−3 Neodymium (60) Nd...

  11. 10 CFR 30.70 - Schedule A-Exempt concentrations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...−3 Chromium (24) Cr 51 2×10−2 Cobalt (27) Co 57 5×10−3 Co 58 1×10−3 Co 60 5×10−4 Copper (29) Cu 64 3... Mercury (80) Hg 197m 2×10−3 Hg 197 3×10−3 Hg 203 2×10−4 Molybdenum (42) Mo 99 2×10−3 Neodymium (60) Nd...

  12. Total dose effects in the 54HC family of microcircuits

    NASA Technical Reports Server (NTRS)

    Ropiak, S.; Sahu, K.; Cleveland, D.

    1984-01-01

    Motorola and National Semiconductor 54HC00 and 54HC74 microcircuits were evaluated using CO-60 to determine their total dose radiation hardness. The devices were found to be radiation soft failing parametrically between 5 and 10 K rads and functionally between 20 and 40 K rads. The failures were bias dependent, relatively insensitive to dose rate, and only annealed moderately when left unbiased at room temperature.

  13. Evaluate the radioactivity along the central thimble hole of a decommissioned heavy water research reactor using TLD approach.

    PubMed

    Lee, Lun-Hui; Sher, Hai-Feng; Lu, I-Hsin; Pan, Lung-Kwang

    2012-04-01

    The radioactivity along the central thimble hole of a decommissioned heavy water research reactor, TRR, was evaluated using TLD approach. The decay radionuclide was verified to be Co-60. The dose along the TRR central thimble hole was detected and revised by performing an unfolding analysis. The revised data reduced to 70-90% of the original data (for example, the maximum dose rate was reduced from 6447 to 4831 mSv/h,) and were more reliable. PMID:22197461

  14. Sensitivity of LDEF foil analyses using ultra-low background germanium vs. large NaI(Tl) multidimensional spectrometers

    NASA Technical Reports Server (NTRS)

    Reeves, James H.; Arthur, Richard J.; Brodzinski, Ronald L.

    1993-01-01

    Cobalt foils and stainless steel samples were analyzed for induced Co-60 activity with both an ultra-low background germanium gamma-ray spectrometer and with a large NaI(Tl) multidimensional spectrometer, both of which use electronic anticoincidence shielding to reduce background counts resulting from cosmic rays. Aluminum samples were analyzed for Na-22. The results, in addition to the relative sensitivities and precisions afforded by the two methods, are presented.

  15. Radiation-resistant, amorphous, all-aromatic poly(arylene ether sulfones) - Synthesis, physical behavior, and degradation characteristics

    NASA Technical Reports Server (NTRS)

    Lewis, D. A.; O'Donnell, James H.; Hedrick, J. L.; Ward, T. C.; Mcgrath, J. E.

    1989-01-01

    The effects of Co-60 gamma radiation on a series of poly(arylene ether sulfones) prepared by nucleophilic activated aromatic substitution are investigated experimentally. The preparation of the test compounds is described, and the test results are presented in extensive tables and graphs. Radiation-induced degradation, as measured by SO2 production, was found to be lowest in compounds based on biphenol rather than bisphenol A; these findings were also well correlated with ultimate-tensile-strain measurements.

  16. Photorecovery of gamma irradiated cultures of blue-green alga, Anacystis nidulans.

    NASA Technical Reports Server (NTRS)

    Asato, Y.

    1971-01-01

    Evidence is given for photorecovery of Anacystis nidulans after exposures to Co 60 gamma radiation. After irradiation the levels of viable cells were higher in cultures kept in white light than in cultures kept dark for 24 hr. The post-irradiation survival rate increase after 30-min exposures to visible light is demonstrated in cultures irradiated with 35 krad. An increase in survival rates was not observed after exposures to ?red' light.

  17. Olive bagasse and nutshell as gamma shielding material

    SciTech Connect

    İnaç, Esra; Baytaş, A. Filiz

    2013-12-16

    Gamma ray linear attenuation coefficients have been measured experimentally for olive bagasse and nutshell by using narrow beam geometry for Co-60 and the values have been compared with soil. These values have been used calculate mean free path, half value layer and tenth value layer parameters. Besides, effect of multi-layered systems (soil + olive bagasse and soil + nutshell) has been analyzed in terms of half value layer.

  18. Gamma Detector Response and Analysis Software - Detector Response Function

    Energy Science and Technology Software Center (ESTSC)

    2014-05-13

    GADRAS-DRF uses a Detector Response Function (DRF) to compute the response of gamma-ray detectors incident radiation. The application includes provision for plotting measured and computed spectra and for characterizing detector response parameters based on measurements of a series of calibration sources (e.g., Ba-133, Cs-137, Co-60, and Th-228). An application program interface enables other programs to access the dynamic-link library that is used to compute spectra.

  19. A simple technique for gamma ray and cosmic ray spectroscopy using plastic scintillator

    NASA Astrophysics Data System (ADS)

    Nandan, Akhilesh P.; Rudra, Sharmili; Neog, Himangshu; Biswas, S.; Mahapatra, S.; Mohanty, B.; Samal, P. K.

    2016-07-01

    A new and simple technique has been developed using plastic scintillator detectors for gamma ray and cosmic ray spectroscopy without single channel analyzer (SCA) or multichannel analyzer (MCA). In these experiments only a leading edge discriminator (LED) and NIM scalers have been used. Energy calibration of gamma spectra in plastic scintillators has been done using Co60 and Cs137 sources. The details of the experimental technique, analysis procedure and experimental results have been presented in this paper.

  20. Electron beam/γ-ray irradiation synthesis of gold nanoparticles and investigation of antioxidant activity

    NASA Astrophysics Data System (ADS)

    Duy Nguyen, Ngoc; Phu Dang, Van; Le, Anh Quoc; Hien Nguyen, Quoc

    2014-12-01

    Colloidal solutions of 1 mM gold nanoparticles (AuNPs) were synthesized by γ-ray Co-60 and electron beam irradiation using 1% water soluble chitosan (WSC) with different molecular weight (Mw) as stabilizer. The AuNPs size measured from TEM images was of 7.1 and 15.1 nm for electron beam and γ-ray Co-60, respectively. The AuNPs sizes of 9.8, 15.1 and 22.4 nm stabilized by different WSC Mw of 155 × 103, 78 × 103 and 29 × 103 g mol-1, respectively, were also synthesized by γ-ray Co-60 irradiation. Antioxidant activity of AuNPs with different size from 7.1 to 20.0 nm was investigated using free radical 2,2‧-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS•+). Results indicated that the smaller size of AuNPs exhibited higher antioxidant activity. In particular, the antioxidant efficiency was of nearly 100, 75, 65, 52 and 30% for 7.1, 9.8, 15.1, 20.0 nm AuNPs and WSC 0.1%, respectively, at the same reaction time of 270 min. Thus, due to the compatibility of WSC and the unique property of AuNPs, the pure colloidal AuNPs/WSC solutions synthesized by irradiation method can be potentially applied in biomedicine, cosmetics and in other fields as well.

  1. Quantitative investigations of megavoltage computed tomography

    NASA Astrophysics Data System (ADS)

    Rogers, Myron; Kerr, Andrew; Salomons, Greg; Schreiner, L. John

    2005-04-01

    Megavoltage computed tomography (MVCT) has been an active area of research and development in image guided radiation therapy. We have been investigating a particular implementation of MVCT in conjunction with studies of the potential for tomotherapy with a Cobalt-60 radiation source. In this paper, we present results comparing MVCT using a Co-60 source and a 4 MV linear accelerator to conventional kVCT imaging. The Co-60 and linac MVCT measurements were obtained with a first generation benchtop CT imager; the KVCT measurements were obtained using a Philips AcQSim CT Simulator). Phantoms containing various inserts ranging in density from air, through lung, soft tissue and bone equivalent materials and extending to high atomic number metals were imaged with the three modalities. The results enable characterization of image artifacts, CT number linearity and beam hardening. The MVCT images have sufficient contrast that soft tissue regions with 2.8% difference in electron density can be visualized. In MVCT, a linear relationship between CT numbers and electron densities extends to materials with Z ~ 60. In the 4MV CT imaging there is a position dependence of the CT numbers within a uniform water phantom, which is absent in Co-60 CT images, indicating the presence of beam hardening artifacts in the linac MVCT images. The differences between kVCT and MVCT will be discussed considering the variation of the photon interactions dominating the images. Our investigations indicate that MVCT has properties that may potentially extend its utility beyond radiation therapy.

  2. La Ninez en Puerto Rico: Resultados del Censo 2000. Un informe de KIDS COUNT/PRB sobre el Censo 2000 (Children in Puerto Rico: Results from the 2000 Census. A KIDS COUNT/PRB Report on Census 2000).

    ERIC Educational Resources Information Center

    Mather, Mark

    This Spanish-language report provides data on children in Puerto Rico based on the 2000 U.S. Census. It compares the situation of Puerto Rico's children with that of children living in the 50 states and the District of Columbia, noting how characteristics of Puerto Rican children have changed over time. Between 1990-2000, the number of Puerto…

  3. [The EMECAM project: a discussion of the results in the participating cities. Estudio Multicéntrico Español sobre la Relación entre la Contaminación Atmosférica y la Mortalidad].

    PubMed

    Ballester Díez, F; Sáez Zafra, M; Pérez-Hoyos, S; Daponte Codina, A; Bellido Blasco, J B; Cañada Martínez, A; Abad Díez, J M; Pérez Boíllos, M J; Alonso Fustel, M E; Taracido Trunk, M; Aguinaga Ontoso, I; Guillén Pérez, J J; Ordóñez Iriarte, J M; Saurina Canals, C; Tenías Burillo, J M

    1999-01-01

    This article draws a comparison and provides a discussion of the findings resulting from the local analyses of the 14 cities participating in the EMECAM Project. An analysis is made of the time series related to mortality, pollutants (particles in suspension, SO2, NO2, O3 and CO), temperature and other factors taken from records of public institutions. By using Poisson autoregressive regression, an estimate has been made of the short-term relationship between the number of deaths and the air pollution indicators in each one of the following cities: Barcelona, metropolitan area of Bilbao, Cartagena, Castellón, Gijón, Huelva, Madrid, Pamplona, Seville, Oviedo, Valencia, Vigo, Vitoria and Saragossa. The findings reveal the air pollution figures in our country to be similar to those of other European cities. The levels of the different pollutants point toward road traffic as being the main source of most of this pollution. A relationship has been found between the mortality and different pollutants in most cities, although the results are not homogeneous among the cities and show variability in the different causes under study. In some cities, especially in those having smaller populations, there have been no findings providing any evidence of a relationship, or the findings themselves are not highly consistent. The meta-analysis will provide estimates for all of the cities as a whole and will allow the possibility of making a more clear-cut assessment of the time lag impact of air pollution on the mortality. Worthy of special mention is the participation in this project of public health officers as actively involved researchers. PMID:10410614

  4. Distintas Modalidades de Aproximar la Educacion al Mundo Productivo: Efectos sobre Variables Psico-Sociales en los Alumnos (Distinct Modalities in Approaching Education for the Productive World: Effects of Socio-psychological Variables on Students).

    ERIC Educational Resources Information Center

    Hidalgo, Abelardo Castro; Carrasco, Decler Martinez; Alegria, Jorge Alegria; Elevancini, Cecilia Maldonado

    2000-01-01

    States that since the 1990s, professional technical education has produced profound transformations in the relationship between education and work in Chile. Examines in a study how modalities of bringing students to the world of work have affected students' socio-psychological characteristics in comparison to training received from traditional…

  5. A Look at the Decisions Hispanic Families Make after the Diagnosis of Deafness = Un estudio sobre las decisiones que toman las familias hispanas despues de un diagnostico de sordera.

    ERIC Educational Resources Information Center

    Steinberg, Annie; Bain, Lisa; Li, Yuelin; Montoya, Louise; Ruperto, Vivian

    This study, written in both English and Spanish, examined the decision-making process of Hispanic families living in the United States who have a child with a hearing loss. Twenty-nine families in four different geographical areas shared their experiences in learning about their child's disability, searching for appropriate interventions, and…

  6. Can We Talk? Helping Families Talk about Self-Esteem, Sex, and Peer Pressure. Training Package = Conversamos? Ayudando a Familias a Hablar sobre la Autoestima, el Sexo, y la Presion de los Amigos. Paquete de Capacitacion.

    ERIC Educational Resources Information Center

    Cappello, Dominic; Newberry, Jerald

    This English and Spanish language multimedia packet comprises an educational curriculum designed to help families talk about self-esteem, sex, and peer pressure with their children in grades 4 through 8. The packet consists of a planning and training manuals, family activity books, and a videotape. The curriculum is comprised of four parent…

  7. A Baseline Study of Strategies to Promote Critical Thinking in the Preschool Classroom (Un Estudio de Base sobre Estrategias para la Promoción de Pensamiento Critico en las Aulas de Preescolar)

    ERIC Educational Resources Information Center

    León, Jenny Melo

    2015-01-01

    The purpose of this study was to identify the different incidents of critical thinking in five preschool classrooms in one school, and the instructional strategies preschool teachers employed in the development of children's critical thinking. The participants in this study were five self-contained preschool teachers and their corresponding…

  8. Sobre un Cambio Sintactico en el Espanol Canario: del Indicativo al Subjuntivo y Condicional (Concerning a Syntactic Change in the Spanish of the Canary Islands: From the Indicative to the Subjunctive and Conditional).

    ERIC Educational Resources Information Center

    Serrano, Maria Jose

    1995-01-01

    Many sociolinguistic studies validate the importance of the relationship among social variables that satisfactorily explain the correlation between linguistic and social phenomena. The intersection of sex, sociocultural level, and age initiates syntactic change that first appears in the vernacular and progresses to the accepted standard. (52…

  9. Directory of Adult Education Periodicals. Seventh Revised Edition. = Repertoire des Periodiques sur l'Education des Adultes. Septieme Edition Revisee. = Repertorio de Periodicos sobre Educacion de Adultos. Septima Edicion Revisada.

    ERIC Educational Resources Information Center

    United Nations Educational, Scientific, and Cultural Organization, Paris (France). Div. of Primary Educ., Literacy & Adult Educ., Educ. in Rural Areas

    Intended as a reference for persons seeking documentation on adult education, this directory provides a list of professional journals and newsletters--international, national, and regional--appearing regularly and dealing either exclusively or substantially with information and activities relating to adult education. This seventh revised edition…

  10. Directory of Adult Education Periodicals. Sixth Revised Edition = Repertoire des Periodiques sur l'Education des Adultes. Sixieme Edition Revisee = Repertorio de Periodicos sobre Educacion de Adultos. Sexta Edicion Revisada.

    ERIC Educational Resources Information Center

    United Nations Educational, Scientific, and Cultural Organization, Paris (France). Div. of Literacy, Adult Education and Rural Development.

    This directory lists approximately 175 adult education periodicals published in Africa, Arab states, Asia and the Pacific, Europe, North America, Latin America and the Caribbean, and other international areas. Within each category, periodicals are further divided into the individual countries in which they are published. Each entry may provide…

  11. [Treatment of type 2 diabetes mellitus in patients with chronic kidney disease. Grupo de Trabajo para el Documento de Consenso sobre el tratamiento de la diabetes tipo 2 en el paciente con enfermedad renal crónica].

    PubMed

    Gómez-Huelgas, Ricardo; Martínez-Castelao, Alberto; Artola, Sara; Górriz, José Luis; Menéndez, Edelmiro

    2014-01-21

    Chronic kidney disease (CKD) and type 2 diabetes mellitus (T2DM) are highly prevalent chronic diseases, which represent an important public health problem and require a multidisciplinary management. T2DM is the main cause of CKD and it also causes a significant comorbidity with regard to non-diabetic nephropathy. Patients with diabetes and kidney disease represent a special risk group as they have higher morbi-mortality as well as higher risk of hypoglycemia than diabetic individuals with a normal kidney function. Treatment of T2DM in patients with CKD is controversial because of the scarcity of available evidence. The current consensus report aims to ease the appropriate selection and dosage of antidiabetic treatments as well as the establishment of safety objectives of glycemic control in patients with CKD. PMID:24268912

  12. Adolescents' Awareness of Environmental Care: Experiences When Writing Short Descriptive Texts in English (Concientización de los adolescentes sobre el cuidado ambiental: experiencias al escribir textos descriptivos cortos en inglés)

    ERIC Educational Resources Information Center

    Jaramillo Urrutia, Lorena; Medina Gutiérrez, Ana Stella

    2011-01-01

    Today it is necessary to approach environmental topics with students in an interdisciplinary manner to mitigate the environmental damages that the Earth is suffering. In this paper we report an action-research and innovation study aimed at sensitizing students with respect to the care and preservation of the environment through the writing of…

  13. Guia para Evaluar y Ubicar a Estudiantes de Idiomas Minoritarios. Para Padres/sobre Padres (A Guide to Assessing and Placing Language Minority Students. For Parents/about Parents).

    ERIC Educational Resources Information Center

    Schwartz, Wendy

    This guide helps parents understand how schools assess their child's English language ability and suggests ways for them to help schools place their children in the most useful language program. All districts must decide which students to test, and then how to test them. Some schools attempt to find out the English skills of all students, and…

  14. Regulando la Enfermedad a través de la Definición y la Restricción: Profesionales de la Salud Hablan sobre el VIH/SIDA1

    PubMed Central

    Rivera, Souhail Malavé; Díaz, Nelson Varas

    2009-01-01

    Resumen Las profesiones de la salud tienen un papel social dual. Por un lado, velan por el mantenimiento de la salud de la población protegiendo el bien común. Por el otro, dictaminan las formas saludables, y por lo tanto socialmente apropiadas, de ser, actuar y pensar. Este último papel, está más ligado al control social de la población que a una preocupación altruista hacia la misma. A través de esta supervisión y control, se construyen los sujetos a los cuales todos/as debemos aspirar a ser para gozar de aceptación social. Los/as profesionales de la salud han jugado un rol protagónico en dicho proceso, siendo los agentes que delimitan y definen lo que es enfermo vs. saludable, útil vs. inútil, apropiado vs. inapropiado. En el caso de la epidemia del VIH, este esfuerzo se ha hecho cada vez más vigente ya que estos/as profesionales juegan un papel importante en el tratamiento de las personas que viven con VIH/SIDA (PVVS). Sin embargo, su función está plasmada de definiciones que sirven para criminalizar a las PVVS. El objetivo de este estudio fue explorar la manera en que una muestra de profesionales de la salud en Puerto Rico construyen a las PVVS. Con este propósito, entrevistamos 80 profesionales de la salud y estudiantes de estas profesiones. Estas entrevistas fueron grabadas, transcritas y sometidas a un análisis de discurso. Los resultados reflejaron que según las personas participantes: 1) la PVVS no es una persona “normal” o funcional bajo los estándares sociales debido a que su salud no se los permite, 2) representa una carga para la sociedad incluyendo familiares, amigos/as, el mundo del trabajo, e incluso para el gobierno, 3) debe ser vigilada porque representa un riesgo para la persona seronegativa que es descrita como saludable y productiva, y 4) necesita que su salud y conducta sexual sean controladas por vía legal y/o por las personas que representan las instituciones sociales, como lo son los/as profesionales de la salud. En este artículo abordamos el potencial rol de la psicología para servir como vehículo de reconstrucción de dichas nociones, tomando en consideración su propio rol en la formación y mantenimiento de dicho sujeto socialmente deseable. PMID:22025907

  15. Mision Informacion: Entrevista a Empleados en el Lugar donde Trabajan; Observar a Obreros mientras Trabajan; Programa sobre Experiencia Laboral (Mission Information: Worksite Interview, Shadow Community Workers, Work Experience Program). CHOICE (Challenging Options in Career Education).

    ERIC Educational Resources Information Center

    Putnam and Northern Westchester Counties Board of Cooperative Educational Services, Yorktown Heights, NY.

    The work-study guide is the third volume in the advanced level of a career education curriculum for elementary-secondary migrant children. Complementing the secondary level job information text and a workbook about decision making and self-awareness, the work-study guide is designed to accompany work exploration and experience programs. It…

  16. Grupo de Trabajo Para la Preparacion del Proyecto Sobre el Desarrolo de Servicias de Bibliotecas y de Informacion Cientifica y Tecnica (Working Group for the Preparation of the Proposal on the Development of Library Services and Scientific and Technical Information).

    ERIC Educational Resources Information Center

    Oficina de Educacion Iberoamericana, Madrid (Spain).

    The Office of Iberoamerican Education, an intergovernmental body based on educational and cultural cooperation for the purpose of disseminating information, documentation, advice, and assistance in the field of education, co-sponsors (with UNESCO) the work represented in this study of library and information planning and facilities in the Andean…

  17. The Latinas' Guide to the Information Superhighway: A Bilingual Guide for Latinas by Latinas = Guia para Mujeres Latinas sobre la Supercarretera de la Informacion: Una Guia Bilingue para Latinas por medio de Latinas.

    ERIC Educational Resources Information Center

    MANA, A National Latina Organization, Washington, DC.

    This guide to the Internet is designed to give Latinas basic information on computers and the information superhighway. Written in both Spanish and English, the guide begins by defining the Internet and making some suggestions about acquiring access to a computer. Among the topics discussed are how to choose an Internet service provider, how to…

  18. Students' Perceptions of the Impact of CLIL in a Mexican BA Program (Percepciones de los estudiantes sobre el impacto de la enseñanza de contenido-lengua integrados en un programa de pregrado en México)

    ERIC Educational Resources Information Center

    Asomoza, Alejandra Nuñez

    2015-01-01

    Content and language integrated learning is an innovative pedagogical approach used in educational institutions worldwide. This study considers information and experiences from various settings in order to explore content and language integrated learning within the Mexican context. This study reports the perceptions of students in a BA program.…

  19. Como Promover el Exito de las Ninas y las Minorias en las Ciencias y en las Matematicas. Para Padres/sobre Padres (How To Promote the Science and Mathematics Achievement of Females and Minorities. For Parents/about Parents).

    ERIC Educational Resources Information Center

    Schwartz, Wendy

    Some minority and female students traditionally have not been given the help they need to enroll and succeed in mathematics and science classes. Now, however, various approaches are available to give these students the extra attention they need. Parents can help children develop an interest in science and mathematics by: (1) identifying role…

  20. Receta para el Exito. Una Guia Actualizada para Padres sobre el Mejoramiento de las Escuelas de Colorado y Logros Estudiantiles (Recipe for Success: An Updated Parents' Guide to Improving Colorado Schools and Student Achievement).

    ERIC Educational Resources Information Center

    Taher, Bonnie; Durr, Pamela

    This Spanish language guide describes ways that parents can help improve student achievement and school quality. It answers such questions as: how to choose the right early-education opportunity for a preschooler; how to make sure a 5-year-old is ready for school; how to help a daughter do well in school; how to work with a daughter's or son's…

  1. International Symposium on Visually Handicapped Infants and Young Children: Birth to Seven (2nd, Aruba, 1987). "The First Steps." Proceedings = Simpasio Internacional sobre Ninos Visualmente Deficientes de Nacimiento hasta Siete Anos (2nd, Aruba, 1987). "Los Primeros Pasos."

    ERIC Educational Resources Information Center

    Palmer, Lillian, Ed.; And Others

    This symposium focused on the special needs of visually handicapped infants and young children. Texts of 48 papers are presented, including keynote addresses by W. Aubrey Webson ("The First Steps") and Heather Hewitt ("First Steps--Parenting, Prevention and Programming"). Regional reports are provided for Japan, Bangladesh, the Middle East, the…

  2. Kathy Talks with Other Mothers about Breastfeeding an Older Baby. Mother-to-Mother Support = Josefa Habla con Otras Mamas sobre el Amamantar a un Bebe Mayorcito. Apoyo Madre a Madre.

    ERIC Educational Resources Information Center

    Magalhaes, Rebecca; Stone-Jimerez, Maryanne; Allen de Smith, Paulina; Smith, Natalia

    These magazine-sized booklets, one in English, one in Spanish, are in cartoon format and designed to be used by people with limited literacy in English or Spanish. The book explains that a 1- or 2-year old breastfed baby is comforted by breastfeeding, breast milk continues to have nutritional value (even if the mother becomes pregnant), and that…

  3. Actas de la 4th mesa redonda sobre investigacion en "Lenguas Extranjeras" en la Universidad Autonoma Metropolitana 1996. (Proceedings from the 4th Roundtable on Investigation in Foreign Languages in the Autonomous Metropolitan University 1996).

    ERIC Educational Resources Information Center

    Zoreda, Margaret Lee, Comp.; Diop, Mamoudou Si, Comp.; Vivaldo Lima, Javier, Comp.

    The articles included in this volume were selected as exemplary papers from the conference in Mexico. The goal of the forum was to provide an opportunity for researchers from the three branches of the Universidad Autonoma Metropolitana (UAM) to meet and discuss research projects currently in progress at the university. The works presented here…

  4. Edades y metalicidades de cinco cúmulos estelares proyectados en dirección a la Nube Menor de Magallanes: implicaciones sobre los procesos de formación y evolución de estos sistemas

    NASA Astrophysics Data System (ADS)

    Piatti, A. E.; Santos, J. F. C.; Clariá, J. J.; Bica, E.; Sarajedini, A.; Geisler, D.

    Washington photometry of the 5 star clusters Lindsay 32, Lindsay 38, Kron 28, Kron 44 and Lindsay 116 and their surrounding fields located towards the Small Magellanic Cloud (SMC) is presented for the first time. From the color-magnitude diagrams, cleaned from field stars contamination, the cluster and SMC field reddenings, ages and metallicities are determined. The ages - derived from the difference in the T1 magnitude betweem the giant clump and the Main Sequence turnoff point - vary between 2 and 6 Gyr, and the metallicities ([Fe/H]) between -1.65 and -1.10. Lindsay 116 is located closer to the Large Magellanic Cloud (LMC) than to the SMC and its fundamental parameters suggests a higher probability of belonging to the LMC. The results obtained in this work, combined with previous estimates of age and metallicity for other seven clusters, allow us to draw the following conclusions: (1) There does not exist an age-position relation in the SMC, but a age-metallicity one. (2) The chemical enrichment in the SMC has been very efficient during the last 5 Gyr. (3) The SMC clusters formation and evolution can be better represented by a bursting star formation process than by a continuum star formation mechanism.

  5. Head Start Program Performance Standards on Services for Children with Disabilities (45-CFR 1308) [and] Normas de Ejecucion del Programa Head Start Sobre Servicios para Ninos con Discapacidades (45-CFR 1308).

    ERIC Educational Resources Information Center

    Administration for Children, Youth, and Families (DHHS), Washington, DC. Head Start Bureau.

    This document consolidates, clarifies, and updates federal regulations on Head Start services for children with disabilities. The regulations are designed to complement the Head Start Program Performance Standards governing services to all enrolled children. Specifically, these regulations require Head Start programs to: (1) design comprehensive…

  6. Manual de Adiestramiento sobre Terapia de Rehidratacion Oral y Control de las Enfermedades Diarreicas (Oral Rehydration Therapy and the Control of Diarrheal Diseases). Training for Development. Peace Corps Information Collection & Exchange Training Manual No. T-53.

    ERIC Educational Resources Information Center

    Clark, Mari; And Others

    This Spanish-language manual was developed to train Peace Corps volunteers and other community health workers in Spanish-speaking countries in oral rehydration therapy (ORT) and the control of diarrheal diseases. Using a competency-based format, the manual contains three training modules (organized in seven sessions) that focus on interrelated…

  7. La Seccion de Investigacion sobre Educacion Medica de la Facultad de Medicina de la Universidad National Autonoma de Mexico (The Medical Education Investigation Section of the School of Medicine of UNAM).

    ERIC Educational Resources Information Center

    Campillo Sainz, Carlos; Alvarez, Tostado, Juan

    This document is an English-language abstract (approximately 1,500 words) of a survey of Mexican medical education needs for the future. To plan for these needs, SISEM of UNAM was formed with the objectives of carrying out and promoting investigations in the different areas of medical education. It also wants to distribute the information…

  8. The Effect of Direct and Indirect Corrective Feedback on Students' Spelling Errors (El efecto de la retroalimentación directa e indirecta sobre los errores de ortografía de los estudiantes)

    ERIC Educational Resources Information Center

    Baleghizadeh, Sasan; Dadashi, Mehdi

    2011-01-01

    The study presented here is an attempt to examine the role of indirect feedback in promoting junior high school students' spelling accuracy in English. It compares the effect of direct feedback with indirect feedback on students' written work dictated by their teacher from their textbooks. Two classes were selected from the Zanjanrood…

  9. Memorias Conferencia Internacional IEEE Mexico 1971, Sobre Sistemas, Redes Y Computadoras. Volumen I and Volumen II. (Proceedings of International Conference of IEEE Concerning Systems, Networks, and Computers. Volume I and Volume II.

    ERIC Educational Resources Information Center

    Concheiro, A. Alonso, Ed.; And Others

    The following papers in English from this international conference may be of particular interest to those in the field of education. T. Nakahara, A. Tsukamota, and M. Matsumoto describe a computer-aided design technique for an economical urban cable television system. W. D. Wasson and R. K. Chitkara outline a recognition scheme based on analysis…

  10. Developing Mathematical Resilience: Students' Voice about the Use of ICT in Classroom (El desarrollo de la capacidad de resiliencia matemática: La voz de los estudiantes sobre el uso de las TIC en la aula)

    ERIC Educational Resources Information Center

    Mota, Ana Isabel; Oliveira, Hélia; Henriques, Ana

    2016-01-01

    Introduction: Mathematical resilience is assumed as one of the most important areas in school context and whose focus should be given priority, due to the distress exhibited by students when learning and understanding basic knowledge in mathematics year after year. The main goal of this research was to study how students attending middle schools…

  11. Fortalecete! Pensamientos e ideas sobre el desarrollo de curriculo para maestras de educacion basica en espanol ("Get Energized! Thoughts and Ideas on Curriculum Development for Spanish Basic Education Teachers").

    ERIC Educational Resources Information Center

    Holyoke JUNTOS Adult Basic Education Collaborative, MA.

    This booklet outlines approaches to adult basic education Spanish literacy. It includes the following: explanatory note for English (non-Spanish) readers; general goals of a Spanish language literacy (SLL) program in Holyoke, Massachusetts; checklists; learning objectives for reading and writing; SLL lesson plan guide; outline for SLL curriculum…

  12. Exploring Authorship Development among Mexican EFL Teacher-Researchers (Exploración sobre el desarrollo de la autoría en los profesores-investigadores de inglés como lengua extranjera)

    ERIC Educational Resources Information Center

    Trujeque Moreno, Eva Estefania; Encinas Prudencio, Fátima; Thomas-Ruzic, Maria

    2015-01-01

    This article presents a multi-theoretical model to address processes of "authorship development" in the English as a foreign language teaching profession. Working within a sociocultural perspective of second-language teacher education, the authors examined six experienced nonnative English-speaking teacher-researchers. Perceptions of…

  13. Western Hemisphere Conference on Persons with Disabilities. Conference Proceedings (Washington, D.C., March 14-18, 1993) = Conferencia Hemisferica Occidental sobre Personas con Discapacidades. Actas de la Conferencia. (Washington, D.C., 14 al 18 de Marzo de 1993).

    ERIC Educational Resources Information Center

    Kelley, Jerry D., Ed.; And Others

    This document presents the proceedings of a conference which brought together delegates and First Ladies representing western hemisphere nations to address needs and issues affecting people with disabilities in the Americas. It presents the texts of two keynote addresses: "Small Triumphs, Big Victories: A Global View of Persons with Disabilities,"…

  14. Aspectos de biología y tablas de vida de Cephalonomia stephanoderis y Prorops nasuta (Himenoptera: Bethilidae) sobre su hospedero la broca del café criada en la dieta artificial Cenibroca modificada.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biological aspects and demographic parameters of the African bethylid wasps Cephalonamia stephanoderis Betrem and Prorops nasuta Waterson (Hymenopterans: Bethylidae) were investigated using diet-reared hosts of Hypothenemus hampei Ferrari (Coleoptera: Scolytidae). The life cycle (28.40 ± SE 0.486 a...

  15. Educacion, Salud y Bienestar para el Nino Preescolar y la Familia (7 de Enero--29 de Febrero de 1996). Informe Curso sobre (Education, Health and Welfare for Small Children. January 7 - February 29, 1996. Report of a Course.)

    ERIC Educational Resources Information Center

    Golda Meir Mount Carmel International Training Centre, Haifa (Israel).

    This Spanish-language report (with an English summary) describes a course on interagency cooperation held at the Golda Meir Mount Carmel International Training Center in Haifa, Israel. The course, with 30 Central and South American participants, discusses the necessity of pooling resources and sharing responsibility among institutions in various…

  16. Percepciones de los estudiantes de education en Venezuela sobre su preparacion e intervencion en violencia domestica. [Perceptions of Education Students in Venezuela about Their Preparation and Intervention in Domestic Violence].

    ERIC Educational Resources Information Center

    McArthur, Anna P.; Cellitti, Anarella; Perez de Linares, Sonia

    1999-01-01

    This study investigated Venezuelan university students' perceptions regarding domestic violence and possible encounters with domestic violence in programs for young children. Students indicated that they expected to encounter only those situations they were prepared to confront, indicating needs for curriculum changes in teacher-training programs.…

  17. The Use of Blogs in English Language Learning: A Study of Student Perceptions (El uso de bitácoras o "blogs" en el aprendizaje del idioma inglés: un estudio sobre las percepciones del estudiante)

    ERIC Educational Resources Information Center

    Ahluwalia, Gurleen; Gupta, Deepti; Aggarwal, Deepak

    2011-01-01

    In this article we present an investigation that focused on the students' perception of using Blogs as a means to supplement in-class language learning activities. Blogs are easy to manage and enable students to publish their work in a chronological manner. They help students to engage in online exchanges and promote learner autonomy. This…

  18. Reaching Higher. A Parent's Guide to the Washington Assessment of Learning. Revised = Para llegar mas arriba. Una guia para padres sobre la evaluacion del aprendizaje de los estudiantes del estado de Washington (Washington Assessment of Student Learning). Revisado.

    ERIC Educational Resources Information Center

    Washington Office of the State Superintendent of Public Instruction, Olympia.

    This guide in English and Spanish is designed to answer questions parents may have about the Washington Assessment of Student Learning (WASL), including how it will help improve their children's education, how it is scored, and how to use the information it provides. In Washington, clear educational goals for subject content, thinking skills, and…

  19. Role of Systematic Formative Assessment on Students' Views of Their Learning (El papel de la evaluación formativa en las percepciones de los estudiantes sobre su aprendizaje)

    ERIC Educational Resources Information Center

    Areiza Restrepo, Hugo Nelson

    2013-01-01

    This article presents a partial report of a small qualitative research study that explored the students' views of their learning during and after the implementation of formative procedures such as self-assessment, feedback, and conferences. The article also includes their perceptions about this implementation. The research was carried out with a…

  20. Essays on Eclipses, Transits and Occultations as Teaching Tools in the Introductory Astronomy College Course. (Spanish Title: Ensayos sobre Eclipses, Tránsitos y Ocultaciones Como Herramientas de Enseñanza en el Curso Universitario Introductorio a la Astronomía.) Ensaios sobre Eclipses, Trânsitos e Ocultações Como Ferramentas de Ensino em um Curso Universitário Introdutório de Astromomia

    NASA Astrophysics Data System (ADS)

    Dcruz, Noella L.

    2014-07-01

    We occasionally include projects in our learner-centered introductory astronomy college course to enable non-science major students explore some astronomical concepts in more detail than otherwise. Such projects also highlight ongoing or upcoming astronomical events. We hope that students will feel more interested in astronomy through projects tied to astronomical events. In Spring 2012, we offered short essays focused on eclipses, transits and occultations to promote the rare transit of Venus that occurred on June 5th, 2012. We asked students to write two short essays from three that were offered. The essays contained descriptive and conceptual parts. They were meant to serve as teaching tools. 62% of 106 essays from 55 students earned A, B or C grades. 21% of 47 feedback survey respondents felt the essays increased their interest in astronomy. 49% of respondents felt that the essays were not educationally beneficial and should not be offered again. The most common written response to our survey indicated that students need more guidance and better preparation in writing successful essays. Since students found the conceptual parts of the essays difficult, in the future we will provide relevant activities prior to essay deadlines to help students create successful essays. Ocasionalmente, incluimos proyectos en nuestro curso de introducción a la astronomía universitario centrado en el alumno para permitir que los estudiantes de carreras no científicas exploren algunos conceptos astronómicos en más detalle que lo habitual. Estos proyectos también ponen en relevancia eventos astronómicos en curso o futuros. Esperamos que los estudiantes se sientan más interesados en la astronomía a través de proyectos vinculados a eventos astronómicos. En el período de primavera de 2012 (EUA), propusimos breves ensayos centrados en los eclipses, tránsitos y ocultaciones para promover el raro tránsito de Venus que se produjo el 5 de junio de 2012. Le pedimos a los estudiantes que escribieran dos ensayos cortos de tres que se proponían. Los ensayos contenían partes descriptivas y conceptuales. Los mismos estaban destinados a servir como herramientas de enseñanza. 62% de los 106 ensayos de 55 estudiantes obtuvo grados A, B o C. 21% de los 47 encuestados que respondieron al cuestionario posterior consideró que los ensayos aumentaron su interés por la astronomía. 49% de los encuestados consideró que los ensayos no eran educacionalmente útiles y que no deben ser propuestos de nuevo. Las respuestas escritas más comunes a nuestra encuesta indicaran que los estudiantes necesitan más orientación y una mejor preparación en la redacción de ensayos exitosos. Dado que los estudiantes encontraron las piezas conceptuales de los ensayos difíciles, en el futuro vamos a ofrecer actividades pertinentes antes de los plazos de redacción para ayudar a los estudiantes a crear ensayos de mayor calidad. Nós ocasionalmente incluímos projetos em nosso curso universitário introdutório centrado no aluno para permitir aos estudantes que pertencem às carreiras não científicas explorar alguns conceitos astronômicos em mais detalhes do que o normal. Tais projetos também enfatizam eventos astronômicos em curso ou futuros. Esperamos que os alunos se sintam mais interessados na astronomia através de projetos ligados a eventos astronômicos. No termo de Primavera de 2012 (EUA), propomos ensaios curtos focados em eclipses, trânsitos e ocultações para promover o raro trânsito de Vênus que ocorreu no dia 5 de junho de 2012. Pedimos aos alunos que escrevessem dois ensaios curtos dentre três que foram propostos. Os ensaios continham partes descritivas e conceituais. Eles foram feitos para servir como ferramentas de ensino. 62% de 106 ensaios de 55 alunos ganhou graus A, B ou C. 21% dos 47 entrevistados que responderam ao levantamento posterior sentiu que os ensaios aumentaram seu interesse na astronomia. 49% dos inquiridos consideraram que os ensaios não eram benéficos para a educação e que não devem ser propostos novamente. As resp

  1. Providing Meaningful Learning for Students of the Sixth Grade of Middle School: a Study on the Moon Phases. (Breton Title: Propiciando Aprendizagem Significativa Para Alunos do Sexto Ano do Ensino Fundamental: um Estudo sobre as Fases da Lua.) Propiciando el Aprendizaje Significativo Para Alumnos del Sexto Nivel de la Educación General Básica: un Estudio sobre Las Fases de la Luna

    NASA Astrophysics Data System (ADS)

    Darroz, Luiz Marcelo; Samudio Pérez, Carlos Ariel; da Rosa, Cleci Werner; Heineck, Renato

    2012-07-01

    We relate in this article a didactic experience studying the moon phases with a group of middle school students of a private school of the municipality of Passo Fundo, RS. Based on David Ausubel's Meaningful Learning Theory, we have sought to develop a proposal following a didactic model which simulates the phases of the Moon, as based on the previous conceptions of the students. The signs of learning were evidenced by means of memory registries of the activity. From the obtained results we believe that the proposal achieved its goals, since the students were able to identify, differentiate and transfer the phenomenon of the moon phases to new contexts. Thus, it is concluded that a methodology focused on a meaningful content for the students is fundamental to the construction and genuine grasping of what is being learned. Neste artigo, relata-se uma experiência didática de estudo das fases da Lua com uma turma do 6° ano do Ensino Fundamental, de uma escola privada do município de Passo Fundo, RS. Tendo como fundamentação teórica a Teoria da Aprendizagem Significativa de David Ausubel, buscou-se desenvolver a proposta a partir de um modelo didático que simula as fases da Lua e com base nas concepções prévias dos estudantes. Os indícios da aprendizagem foram constatados através de registros de memórias da atividade. Pelos resultados apresentados, acredita-se que a proposta alcançou seus objetivos, uma vez que os estudantes conseguiram identificar, diferenciar e transferir o fenômeno das fases da Lua para novos contextos. Assim, conclui-se que uma metodologia com enfoque em um conteúdo significativo ao estudante é fundamental para a construção e compreensão genuína do que está sendo aprendido. En este artículo se relata una experiencia didáctica de estudio de las fases de la Luna con una clase de 6º año de la educación general básica de una escuela privada del municipio de Passo Fundo, RS. Teniendo como fundamentación teórica la Teoría del Aprendizaje Significativo de David Ausubel, se buscó desenvolver la propuesta a partir de un modelo didáctico que simula las Fases de la Luna, usando como base las concepciones previas de los estudiantes. Los indicios del aprendizaje fueron verificados a través de registros de memorias de la actividad. Por los resultados obtenidos creemos que la propuesta alcanzó sus objetivos, una vez que los estudiantes consiguieron identificar y transferir el fenómeno de las fases de la Luna para nuevos contextos. Así, se concluye que una metodología con enfoque en un contenido significativo para el estudiante es fundamental para la construcción y comprensión genuina de lo que está siendo aprendido.

  2. Investigation of Megavoltage Digital Tomosynthesis using a Cobalt-60 Source

    NASA Astrophysics Data System (ADS)

    MacDonald, Amy

    The ability for megavoltage computed tomography patient setup verification using a cobalt-60 (Co-60) gamma ray source has been established in the context of cobalt tomotherapy. However, it would be beneficial to establish improved cobalt imaging that could be used on more conventional units. In terms of safety and efficiency, this imaging technique would provide the patient with less exposure to radiation. Digital tomosynthesis (DT) is an imaging modality that may provide improved depth localization and in-plane visibility compared to conventional portal imaging in modern Co-60 radiation therapy. DT is a practical and efficient method of achieving depth localization from a limited gantry rotation and a limited number of projections. In DT, each plane of the imaging volume can be brought into focus by relatively displacing the composite images and superimposing the shifted dataset according to the acquisition geometry. Digital flat-panel technology has replaced the need for multiple film exposures and therefore the speed of imaging and capabilities for image processing has put DT in the forefront of both clinical and industrial imaging applications. The objective of this work is to develop and evaluate the performance of an experimental system for megavoltage digital tomosynthesis ( MVDT) imaging using a Co-60 gamma ray source. Linear and isocentric acquisition geometries are implemented using tomographic angles of 20--60° and 10--60 projections. Reconstruction algorithms are designed for both acquisition geometries. Using the backprojection approach, the data are shifted and added to reconstruct focal planes of interest. Depth localization and its dependence on tomographic angle and projection density are visualized with an anthropomorphic head phantom. High contrast resolution at localized depths is quantified using the modulation transfer function approach. Results show that focal-plane visibility is improved for larger tomographic angles and that focal

  3. Prevención del cáncer de cavidad oral y orofaringe (PDQ®)—Versión para pacientes

    Cancer.gov

    Sumario de información revisada por expertos sobre factores que pueden influir en el riesgo de presentar cáncer de labio, cavidad oral y orofaringe, y sobre las investigaciones dirigidas a prevenir esta enfermedad.

  4. Upper Extremity Radiography

    MedlinePlus

    ... los anillos, pulseras y se acueste sobre la mesa de rayos X relojes, para que las áreas ... alhajas puedan radiografiarse. Si el brazo sobre la mesa. Se colocarán no puede sacarse un anillo porque ...

  5. 48 CFR 252.229-7005 - Tax exemptions (Spain).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Transfer Tax). (4) Impuesto Sobre el Lujo (Luxury Tax). (5) Actos Juridocos Documentados (Legal Official Transactions). (6) Impuesto Sobre el Trafico de Empresas (Business Trade Tax). (7) Impuestos Especiales de Fabricacion (Special Products Tax). (8) Impuesto Sobre el Petroleo y Derivados (Tax on Petroleum and its...

  6. Té y prevencìón de cáncer

    Cancer.gov

    Hoja informativa que resume los resultados de estudios realizados sobre el té y la prevención del cáncer. Incluye información sobre los ingredientes del té y las consideraciones de seguridad sobre el consumo de esta bebida.

  7. Development, physical properties and clinical applicability of a mechanical Multileaf Collimator for the use in Cobalt-60 radiotherapy

    NASA Astrophysics Data System (ADS)

    Langhans, Marco; Echner, Gernot; Runz, Armin; Baumann, Martin; Xu, Mark; Ueltzhöffer, Stefan; Häring, Peter; Schlegel, Wolfgang

    2015-04-01

    According to the Directory of Radiotherapy Centres (DIRAC) there are 2348 Cobalt-60 (Co-60) teletherapy units worldwide, most of them in low and middle income countries, compared to 11046 clinical accelerators. To improve teletherapy with Co-60, a mechanical Multi-Leaf Collimator (MLC) was developed, working with pneumatic pressure and thus independent of electricity supply. Instead of tungsten, brass was used as leaf material to make the mechanical MLC more affordable. The physical properties and clinical applicability of this mechanical MLC are presented here. The leakage strongly depends on the fieldsize of the therapy unit due to scatter effects. The maximum transmission through the leaves measured 2.5 cm from the end-to-end gap, within a field size of 20 cm × 30 cm defined by jaws of the therapy unit at 80 cm SAD, amounts 4.2%, normalized to an open 10 cm × 10 cm field, created by the mechanical MLC. Within a precollimated field size of 12.5 cm × 12.5 cm, the end-to-end leakage is 6.5% normalized to an open 10 cm × 10 cm field as well. This characteristic is clinically acceptable considering the criteria for non-IMRT MLCs of the International Electrotechnical Commission (IEC 60601-2-1). The penumbra for a 10 cm × 10 cm field was measured to be 9.14 mm in plane and 8.38 mm cross plane. The clinical applicability of the designed mechanical MLC was affirmed by measurements relating to all relevant clinical properties such as penumbra, leakage, output factors and field widths. Hence this novel device presents an apt way forward to make radiotherapy with conformal fields possible in low-infrastructure environments, using gantry based Co-60 therapy units.

  8. Development, physical properties and clinical applicability of a mechanical Multileaf Collimator for the use in Cobalt-60 radiotherapy.

    PubMed

    Langhans, Marco; Echner, Gernot; Runz, Armin; Baumann, Martin; Xu, Mark; Ueltzhöffer, Stefan; Häring, Peter; Schlegel, Wolfgang

    2015-04-21

    According to the Directory of Radiotherapy Centres (DIRAC) there are 2348 Cobalt-60 (Co-60) teletherapy units worldwide, most of them in low and middle income countries, compared to 11046 clinical accelerators. To improve teletherapy with Co-60, a mechanical Multi-Leaf Collimator (MLC) was developed, working with pneumatic pressure and thus independent of electricity supply. Instead of tungsten, brass was used as leaf material to make the mechanical MLC more affordable. The physical properties and clinical applicability of this mechanical MLC are presented here. The leakage strongly depends on the fieldsize of the therapy unit due to scatter effects. The maximum transmission through the leaves measured 2.5 cm from the end-to-end gap, within a field size of 20 cm × 30 cm defined by jaws of the therapy unit at 80 cm SAD, amounts 4.2%, normalized to an open 10 cm × 10 cm field, created by the mechanical MLC. Within a precollimated field size of 12.5 cm × 12.5 cm, the end-to-end leakage is 6.5% normalized to an open 10 cm × 10 cm field as well. This characteristic is clinically acceptable considering the criteria for non-IMRT MLCs of the International Electrotechnical Commission (IEC 60601-2-1). The penumbra for a 10 cm × 10 cm field was measured to be 9.14 mm in plane and 8.38 mm cross plane. The clinical applicability of the designed mechanical MLC was affirmed by measurements relating to all relevant clinical properties such as penumbra, leakage, output factors and field widths. Hence this novel device presents an apt way forward to make radiotherapy with conformal fields possible in low-infrastructure environments, using gantry based Co-60 therapy units. PMID:25831017

  9. Using laboratory x-ray and cobalt-60 irradiations to predict CMOS device response in strategic and space environments

    SciTech Connect

    Fleetwood, D.M.; Winokur, P.S.; Schwank, J.R.

    1988-12-01

    The postirradiation response of CMOS transistors with 30-60 nm gate oxides is investigated as a function of radiation energy, total dose, dose rate, and annealing time. Measurements of threshold voltage, oxide-trapped charge, and interface traps are reported for times ranging from 10 ms to 4 months following LINAC, Co-60, Cs-137, and 10-keV x-ray irradiations. Exposure dose rates vary by 11 orders of magnitude: from 0.05 to 6 x 10/sup 9/ rad(SiO/sub 2/)/s. To within the +- 10 percent uncertainty in the overall dosimetry, no true dose rate effects on MOS device response are observed. Further, for these devices, interface trap and oxide-trapped charge densities are found to be linear with total dose. Based on these results, and subject to future verification, preliminary recommendations are made for lot acceptance testing of hardened CMOS circuits and devices intended for use in space and strategic environments. These include an endorsement of Co-60 exposure and elevated temperature annealing for qualification of devices for use in space environments and a recommendation for the use of x-ray exposures at dose rates greater than -- 2000 rad (SiO/sub 2/)/s, in addition to Co-60 irradiations according to MIL-STD method 1019.3, for strategic applications. These tests are practical to implement, and should provide greatly improved confidence in CMOS performance in space and strategic applications over that obtained with MIL-STD 1019.3 testing.

  10. The effects of space radiation on thin films of YBa2Cu3O(sub 7-x)

    NASA Technical Reports Server (NTRS)

    Herschitz, R.; Bogorad, A.; Bowman, C.; Seehra, S. S.; Mogro-Campero, A.; Turner, L. G.

    1990-01-01

    This investigation had two objectives: (1) to determine the effects of space radiation on superconductor parameters that are most important in space applications; and (2) to determine whether this effect can be simulated with Co-60 gamma rays, the standard test method for space materials. Thin films of yttrium barium copper oxide (YBCO) were formed by coevaporation of Y, BaF2, and Cu and post-annealing in wet oxygen at 850 C for 3.5 h. The substrate used was (100) silicon with an evaporated zirconia buffer layer. The samples were characterized by four point probe electrical measurements as a function of temperature. The parameters measured were the zero resistance transition temperature (T sub c) and the room temperature resistance. The samples were then exposed to Co-60 gamma-rays in air and in pure nitrogen, and to 780 keV electrons, in air. The parameters were then remeasured. The results are summarized. The results indicate little or no degradation in the parameters measured for samples exposed up to 10 Mrads of gamma-rays in nitrogen. However, complete degradation of samples exposed to 10-Mrad in air was observed. This degradation is preliminarily attributed to the high level of ozone generated in the chamber by the gamma-ray interaction with air. It can be concluded that: (1) the electron component of space radiation does not degrade the critical temperature of the YBCO films described, at least for energies around 800 keV and doses similar to those received by surface materials on spacecraft in typical remote sensing missions; and (2) for qualifying this and other superconducting materials against the space-radiation threat the standard test method in the aerospace industry, namely, exposure to Co-60 gamma-rays in air, may require some further investigation. As a minimum, the sample must be either in vacuum or in positive nitrogen pressure.

  11. Variation of sensitometric curves of radiographic films in high energy photon beams.

    PubMed

    Danciu, C; Proimos, B S; Rosenwald, J C; Mijnheer, B J

    2001-06-01

    Film dosimetry is an important tool for the verification of irradiation techniques. The shape of the sensitometric curve depends on the type of film as well as on the irradiation and processing conditions. Existing data concerning the influence of irradiation geometry on the sensitometric curve are conflicting. In particular the variation of optical density, OD, with field size and depth in a phantom shows large differences in magnitude between various authors. This variation, as well as the effect of beam energy and film plane orientation on OD, was therefore investigated for two types of film, Kodak X-Omat V and Agfa Structurix D2. Films were positioned in a solid phantom, either perpendicular or (almost) parallel to the beam axis, and irradiated to different dose levels using various photon beams (Co-60, 6 MV, 15 MV, 18 MV, 45 MV). It was found that the sensitometric curves of the Kodak film derived at different depths are almost identical for the four x-ray beams. For the Kodak film the differences in OD with depth are less than 2%, except for the Co-60 beam, where the difference is about 4% at 10 cm depth for a 15 cm x 15 cm field. The slope of the sensitometric curve of the Agfa film is somewhat more dependent on photon beam energy, depth and field size. The sensitometric curves of both types of film are almost independent of the film plane orientation, except for shallow depths. For Co-60 and for the same dose, the Kodak and Agfa films gave at dose maximum an OD lower by 4% and 6%, respectively, for the parallel compared to the perpendicular geometry. Good dosimetric results can be obtained if films from the same batch are irradiated with small to moderate field sizes (up to about 15 cm x 15 cm), at moderate depths (up to about 15 cm), using a single calibration curve, e.g., for a 10 cm x 10 cm field. PMID:11439493

  12. [Effect of eye shielding block position on dose to lens during radiation therapy].

    PubMed

    Hong, J H; Lin, F J; Chen, H H

    1990-02-01

    The lens of the eye is very sensitive to radiation and a low dose of radiation may induce cataracts a few years after radiation therapy. In treatment of head and neck tumors, such as cancer of the ethmoid or maxillary sinus, an adequate eye shielding block is mandatory for reducing the lens dose in order to prevent cataract formation. Experiments were designed to simulate the setup of the lens during radiation therapy and it was observed that the dose to the lens was correlated with the distance between the eye shielding block and the eye surface for Co-60, 10MV and 6MV X-rays. With properly fabricated divergent blocks, the optimal shielding points were found to be 6 cm, 0.9 cm and 1.4 cm above the eye surface for Co-60, 10MV and 6MV X-rays, respectively. In a 10 x 10 cm2 field, by moving the eye shielding block on the blocking tray to the optimal shielding point near the surface, the dose to the lens can be reduced from 14% to 8% for Co-60 beams and from 17% to 7% for 10MV and 6MV X-rays. This effect is more evident in larger field sizes. We recommend that the eye shielding block be placed at the optimal shielding point to minimize the dose to the lens. If the eye shielding block cannot be placed at the optimal shielding point, a simple coin placed on the eye lid surface will also reduce the lens dose substantially when a regular eye shielding block is placed on the blocking tray (Lin's coin effect). PMID:1973723

  13. Validation of virtual spectrometer created in RADlab1.03

    PubMed Central

    Pandey, Anil Kumar; Patel, Chetan; Bal, Chandrasekhar; Kumar, Rakesh

    2015-01-01

    Spectrometer is used to perform various in vitro tests. The ability to successfully perform these tests depends on technologist's skill. Therefore, proper training of technologists is mandatory in gamma spectrometry. During the training, they need to have sufficient practice to gain sound theoretical and practical knowledge. High cost of spectrometer and risk of their damage during independent practice may hamper the process of proper training. Hence, there is a need of cheaper and more feasible option. Virtual spectrometer created in RADlab1.03 can address this issue. The immediate objective of this paper is to validate this virtual spectrometer so as to be used as an educational and research tool for trainees. Virtual spectrometer was calibrated using Cs-137 standard source and Cs-137 spectrum was recorded by positioning 28106 Bq Cs-137 source at 2.35 cm above top surface of the well, 1 cm above from the bottom of the well and at the bottom of the well. Ba-133 and Co-60 spectrum were also recorded. The experiments were repeated with real spectrometer for exactly the same conditions as applied to the virtual spectrometer. The paired t-test was applied to find the difference in mean photopeak at 5% level of significance. The sample data provided satisfactory evidence that mean photopeak obtained with real as well as virtual spectrometer were same at P value of 4.641 × 10−4,1.57 × 10−12,1.40 × 10−24, 1.26 × 10−16, and 8.7 × 10−9 for Cs-137 (photopeak: 664 keV, Co-60 (photopeak: 1181 keV), Co-60 (photopeak: Co-1348 keV), Ba-133 (photopeak: 304 keV) and Ba-133 (photopeak: 364 keV) respectively. PMID:25589799

  14. Characteristics of mobile MOSFET dosimetry system for megavoltage photon beams.

    PubMed

    Kumar, A Sathish; Sharma, S D; Ravindran, B Paul

    2014-07-01

    The characteristics of a mobile metal oxide semiconductor field effect transistor (mobile MOSFET) detector for standard bias were investigated for megavoltage photon beams. This study was performed with a brass alloy build-up cap for three energies namely Co-60, 6 and 15 MV photon beams. The MOSFETs were calibrated and the performance characteristics were analyzed with respect to dose rate dependence, energy dependence, field size dependence, linearity, build-up factor, and angular dependence for all the three energies. A linear dose-response curve was noted for Co-60, 6 MV, and 15 MV photons. The calibration factors were found to be 1.03, 1, and 0.79 cGy/mV for Co-60, 6 MV, and 15 MV photon energies, respectively. The calibration graph has been obtained to the dose up to 600 cGy, and the dose-response curve was found to be linear. The MOSFETs were found to be energy independent both for measurements performed at depth as well as on the surface with build-up. However, field size dependence was also analyzed for variable field sizes and found to be field size independent. Angular dependence was analyzed by keeping the MOSFET dosimeter in parallel and perpendicular orientation to the angle of incidence of the radiation with and without build-up on the surface of the phantom. The maximum variation for the three energies was found to be within ± 2% for the gantry angles 90° and 270°, the deviations without the build-up for the same gantry angles were found to be 6%, 25%, and 60%, respectively. The MOSFET response was found to be independent of dose rate for all three energies. The dosimetric characteristics of the MOSFET detector make it a suitable in vivo dosimeter for megavoltage photon beams. PMID:25190992

  15. The effects of space radiation on thin films of YBa2Cu3O(7-x)

    NASA Technical Reports Server (NTRS)

    Herschitz, R.; Bogorad, A.; Bowman, C.; Seehra, S. S.; Mogro-Campero, A.; Turner, L. G.

    1991-01-01

    This investigation had two objectives: (1) to determine the effects of space radiation on superconductor parameters that are most important in space applications; and (2) to determine whether this effect can be simulated with Co-60 gamma rays, the standard test method for space materials. Thin films of yttrium barium copper oxide (YBCO) were formed by coevaporation of Y, BaF2, and Cu and post-annealing in wet oxygen at 850 C for 3.5 h. The substrate used was (100) silicon with an evaporated zirconia buffer layer. The samples were characterized by four point probe electrical measurements as a function of temperature. The parameters measured were the zero resistance transition temperature T(sub c) and the room temperature resistance. The samples were then exposed to Co-60 gamma-rays in air and in pure nitrogen, and to 780 keV electrons, in air. The parameters were then remeasured. The results are summarized. The results indicate little or no degradation in the parameters measured for samples exposed up to 10 Mrads of gamma-rays in nitrogen. However, complete degradation is preliminarily attributed to the high level of ozone generated in the chamber by the gamma-ray interaction with air. It can be concluded that: (1) the electron component of space radiation does not degrade the critical temperature of the YBCO films described, at least for energies around 800 keV and doses similar to those received by surface materials on spacecraft in typical remote sensing missions; and (2) for qualifying this and other superconducting materials against the space-radiation threat the standard test method used in the aerospace industry, namely, exposure to Co-60 gamma-rays in air, may require some further investigation. As a minimum, the sample must be either in vacuum or in positive nitrogen pressure.

  16. Characteristics of mobile MOSFET dosimetry system for megavoltage photon beams

    PubMed Central

    Kumar, A. Sathish; Sharma, S. D.; Ravindran, B. Paul

    2014-01-01

    The characteristics of a mobile metal oxide semiconductor field effect transistor (mobile MOSFET) detector for standard bias were investigated for megavoltage photon beams. This study was performed with a brass alloy build-up cap for three energies namely Co-60, 6 and 15 MV photon beams. The MOSFETs were calibrated and the performance characteristics were analyzed with respect to dose rate dependence, energy dependence, field size dependence, linearity, build-up factor, and angular dependence for all the three energies. A linear dose-response curve was noted for Co-60, 6 MV, and 15 MV photons. The calibration factors were found to be 1.03, 1, and 0.79 cGy/mV for Co-60, 6 MV, and 15 MV photon energies, respectively. The calibration graph has been obtained to the dose up to 600 cGy, and the dose-response curve was found to be linear. The MOSFETs were found to be energy independent both for measurements performed at depth as well as on the surface with build-up. However, field size dependence was also analyzed for variable field sizes and found to be field size independent. Angular dependence was analyzed by keeping the MOSFET dosimeter in parallel and perpendicular orientation to the angle of incidence of the radiation with and without build-up on the surface of the phantom. The maximum variation for the three energies was found to be within ± 2% for the gantry angles 90° and 270°, the deviations without the build-up for the same gantry angles were found to be 6%, 25%, and 60%, respectively. The MOSFET response was found to be independent of dose rate for all three energies. The dosimetric characteristics of the MOSFET detector make it a suitable in vivo dosimeter for megavoltage photon beams. PMID:25190992

  17. Structural and thermal properties of γ – irradiated Bombyx mori silk fibroin films

    SciTech Connect

    Madhukumar, R.; Asha, S.; Rao, B. Lakshmeesha; Shivananda, C. S.; Harish, K. V.; Sangappa; Sarojini, B. K.; Somashekar, R.

    2015-06-24

    The gamma radiation-induced change in structural and thermal properties of Bombyx mori silk fibroin films were investigated and have been correlated with the applied radiation doses. Irradiation of samples were carried out in dry air at room temperature using Co-60 source, and radiation doses are in the range of 0 - 300 kGy. Structural and thermal properties of the irradiated silk films were studied using X-ray diffraction (XRD), Differential Scanning Calorimetry (DSC) and Thermogravimetric analysis (TGA) and compared with unirradiated sample. Interesting results are discussed in this report.

  18. Investigation of radiation effects in Hiroshima and Nagasaki using a general Monte Carlo-discrete ordinates coupling scheme

    SciTech Connect

    Cramer, S.N.; Slater, C.O.

    1990-05-01

    A general Monte Carlo-discrete ordinates radiation transport coupling procedure has been created to study effects of the radiation environment in Hiroshima and Nagasaki due to the bombing of these two cities. The forward two-dimensional free-field air-over-ground flux is coupled with an adjoint Monte Carlo calculation. The size, orientation, or translation of the Monte Carlo geometry is unrestricted. The radiation effects calculated are the dose in the interior of a large concrete building in Nagasaki and the activation production of Co-60 and P-32 in Hiroshima. 20 refs., 6 figs., 1 tab.

  19. Diagnosis and treatment of olfactory neuroblastomas in seven patients. [/sup 60/Co

    SciTech Connect

    Daly, N.J.; Voigt, J.J.; Combes, P.F.

    1980-12-01

    A group of 7 patients with olfactory neuroblastomas (ON) treated at Centre Claudius Regaud (CCR) from 1966 to 1978 are presented. Clinical and radiological evaluation showed 4/7 patients with endocranial extension of tumor (stage C disease). All patients were treated by external irradiation (Co60) after biopsies (3), surgical curettage (3) or whole ethmoidectomy (1). No patient had tumor failures in irradiated volumes where doses were above 4000 rad. Four patients had tumor relapses outside treated volumes, two in cervical nodes. Five patients were alive without clinical disease from 2 to 12.5 years after initial treatment. The role of external radiotherapy in the management of ON is particularly discussed.

  20. Quantitation of heavy ion damage to the mammalian brain - Some preliminary findings

    NASA Technical Reports Server (NTRS)

    Cox, A. B.; Kraft, L. M.

    1984-01-01

    For several years, studies have been conducted regarding late effects of particulate radiations in mammalian tissues, taking into account the brains of rodents and lagomorphs. Recently, it has become feasible to quantify pathological damage and morpho-physiologic alterations accurately in large numbers of histological specimens. New investigative procedures make use of computer-assisted automated image analysis systems. Details regarding the employed methodology are discussed along with the results of the information. The radiations of high linear energy transfer (LET) cause apparently earlier and more dramatic shrinkage of olfactory glomeruli in exposed rabbit brains than comparable doses of Co-60 gamma photons.

  1. Design and application of 3D-printed stepless beam modulators in proton therapy.

    PubMed

    Lindsay, C; Kumlin, J; Martinez, D M; Jirasek, A; Hoehr, C

    2016-06-01

    A new method for the design of stepless beam modulators for proton therapy is described and verified. Simulations of the classic designs are compared against the stepless method for various modulation widths which are clinically applicable in proton eye therapy. Three modulator wheels were printed using a Stratasys Objet30 3D printer. The resulting depth dose distributions showed improved uniformity over the classic stepped designs. Simulated results imply a possible improvement in distal penumbra width; however, more accurate measurements are needed to fully verify this effect. Lastly, simulations were done to model bio-equivalence to Co-60 cell kill. A wheel was successfully designed to flatten this metric. PMID:27182839

  2. Radioactive tracer test to develop a recycling system for operating reactor scrap metal

    SciTech Connect

    Umemura, A.; Kimura, K.; Takahashi, K.; Sakurai, D.; Yamamoto, M.; Abe, S.

    1995-12-31

    A demonstration test using radio-isotope (RI) tracers during the manufacturing of inner drum shielding material from the recycling of operating reactor scrap metal was completed and the following results were obtained. The behavior of five radionuclides (Mn-54, Co-60, Zn-65, Sr-85 and Cs-137) was established. The time-dependent behaviors of the radionuclides in molten steel and in slag were investigated. The radioactivity distributions in metal products were homogeneous. Dose equivalent rates in the working area were below background levels and radioactive dust concentrations in the air were below detection limits.

  3. Prediction of long-term radiation kinetics of transmission spectra of commerical optical glasses

    NASA Astrophysics Data System (ADS)

    Gusarov, Andrei I.; Doyle, Dominic B.; Fruit, Michel; Kinet, Damien P.

    2002-09-01

    We analyze the applicability of a number of exponent-type phenomenological kinetics for transmission degradation prediction in commercial optical glasses during and after irradiation. The analysis is based on post-radiation transmission measurements over a 5 years time interval of a commercial boro-silicate glass (BK7, Schott). A conclusion is drawn that the choice should be made between the stretched-exponential and the multi-exponential functions. We apply those kinetics to simulate kinetics of BK7 glass transmission spectra subject to Co60 gamma-radiation in the framework of the previously developed phenomenological model. Calculated transmission spectra agree well with our experimental data.

  4. Radiation fields and dose assessments in Korean nuclear power plants.

    PubMed

    Kim, Hee Geun; Kong, Tae Young; Jeong, Woo Tae; Kim, Seok Tae

    2011-07-01

    In the primary systems of nuclear power plants (NPPs), various radionuclides including fission products and corrosion products are generated due to the complex water chemistry conditions. In particular, (3)H, (14)C, (58)Co, (60)Co, (137)Cs, and (131)I are important or potential radionuclides with respect to dose assessment for workers and the management of radioactive effluents or dose assessment for the public. In this paper, the dominant contributors to the dose for workers and the public were reviewed and the process of dose assessment attributable to those contributors was investigated. Furthermore, an analysis was carried out on some examples of dose to workers during NPP operation. PMID:21498858

  5. Nuclear Decay Data for the International Reactor Dosimetry Library for Fission and Fusion (IRDFF): Updated Evaluations of the Half-Lives and Gamma Ray Intensities

    NASA Astrophysics Data System (ADS)

    Chechev, Valery P.; Kuzmenko, Nikolay K.

    2016-02-01

    Updated evaluations of the half-lives and prominent gamma ray intensities have been presented for 20 radionuclides - dosimetry reaction residuals. The new values of these decay characteristics recommended for the IRDFF library were obtained using the approaches and methodology adopted by the working group of the Decay Data Evaluation Project (DDEP) cooperation. The experimental data published up to 2014 were taken into account in updated evaluations. The list of radionuclides includes 3H, 18F, 22Na, 24Na, 46Sc, 51Cr, 54Mn, 59Fe, 57Co, 60Co, 57Ni, 64Cu, 88Y, 132Te, 131I, 140Ba, 140La, 141Ce, 182Ta, 198Au.

  6. X-Ray-Diffraction Tests Of Irradiated Electronic Devices: I

    NASA Technical Reports Server (NTRS)

    Shaw, David C.; Lowry, Lynn E.; Barnes, Charles E.

    1993-01-01

    X-ray-diffraction tests performed on aluminum conductors in commercial HI1-507A complementary metal oxide/semiconductor (CMOS) integrated-circuit analog multiplexers, both before and after circuits exposed to ionizing radiation from Co(60) source, and after postirradiation annealing at ambient and elevated temperatures. Tests in addition to electrical tests performed to determine effects of irradiation and of postirradiation annealing on electrical operating characteristics of circuits. Investigators sought to determine whether relationship between effects of irradiation on devices and physical stresses within devices. X-ray diffraction potentially useful for nondestructive measurement of stresses.

  7. Prediction and measurement of radiation damage to CMOS devices on board spacecraft

    NASA Technical Reports Server (NTRS)

    Cliff, R. A.; Danchenko, V.; Stassinopoulos, E. G.; Sing, M.; Brucker, G. J.; Ohanian, R. S.

    1976-01-01

    The initial results obtained from the Complementary Metal Oxide Semiconductors Radiation Effects Measurement experiment are presented. Predictions of radiation damage to C-MOS devices are based on standard environment models and computational techniques. A comparison of the shifts in CMOS threshold potentials, that is, those measured in space to those obtained from the on the ground simulation experiment with Co 60, indicated that the measured space damage is greater than predicted by a factor of two for shields thicker than 100 mils (2.54 mm), but agrees well with predictions for the thinner shields.

  8. In-Situ Chemical Precipitation of Radioactive Liquid Waste - 12492

    SciTech Connect

    Osmanlioglu, Ahmet Erdal

    2012-07-01

    This paper presented in-situ chemical precipitation for radioactive liquid waste by using chemical agents. Results are reported on large-scale implementation on the removal of {sup 137}Cs, {sup 134}Cs and {sup 60}Co from liquid radioactive waste generating from Nuclear Research and Training Centre. Total amount of liquid radioactive waste was 35 m{sup 3} and main radionuclides were Cs-137, Cs- 134 and Co-60. Initial radioactivity concentration of the liquid waste was 2264, 17 and 9 Bq/liter for Cs-137, Cs-134 and Co-60 respectively. Potassium ferro cyanide was selected as chemical agent at high pH levels 8-10 according to laboratory tests. After the process, radioactive sludge precipitated at the bottom of the tank and decontaminated clean liquid was evaluated depending on discharge limits. By this precipitation method decontamination factors were determined as 60, 9 and 17 for Cs-137, Cs-134 and Co-60 respectively. At the bottom of the tank radioactive sludge amount was 0.98 m{sup 3}. It was transferred by sludge pumps to cementation unit for solidification. By in situ chemical processing 97% of volume reduction was achieved. Using the optimal concentration of 0.75 M potassium ferro cyanide about 98% of the {sup 137}Cs can be removed at pH 8. The Potassium ferro cyanide precipitation method could be used successfully in large scale applications with nickel and ferrum agents for removal of Cs-137, Cs-134 and Co- 60. Although DF values of laboratory test were much higher than in-situ implementation, liquid radioactive waste was decontaminated successfully by using potassium ferro cyanide. Majority of liquid waste were discharged as clean liquid. %97.2 volumetric amount of liquid waste was cleaned and discharged at the original site. Reduced amount of sludge transportation in drums is more economical and safer method than liquid transportation. Although DF values could be different for each of applications related to main specifications of original liquid waste, this

  9. Design and application of 3D-printed stepless beam modulators in proton therapy

    NASA Astrophysics Data System (ADS)

    Lindsay, C.; Kumlin, J.; Martinez, D. M.; Jirasek, A.; Hoehr, C.

    2016-06-01

    A new method for the design of stepless beam modulators for proton therapy is described and verified. Simulations of the classic designs are compared against the stepless method for various modulation widths which are clinically applicable in proton eye therapy. Three modulator wheels were printed using a Stratasys Objet30 3D printer. The resulting depth dose distributions showed improved uniformity over the classic stepped designs. Simulated results imply a possible improvement in distal penumbra width; however, more accurate measurements are needed to fully verify this effect. Lastly, simulations were done to model bio-equivalence to Co-60 cell kill. A wheel was successfully designed to flatten this metric.

  10. Terpolymerization of ethylene, sulfur dioxide and carbon monoxide

    DOEpatents

    Johnson, Richard; Steinberg, Meyer

    1981-01-01

    This invention relates to a high molecular weight terpolymer of ethylene, sulfur dioxide and carbon monoxide stable to 280.degree. C. and containing as little as 36 mol % ethylene and about 41-51 mol % sulfur dioxide; and to the method of producing said terpolymer by irradiation of a liquid and gaseous mixture of ethylene, sulfur dioxide and carbon monoxide by means of Co-60 gamma rays or an electron beam, at a temperature of about 10.degree.-50.degree. C., and at a pressure of about 140 to 680 atmospheres, to initiate polymerization.

  11. A biotechnological project with a gamma radiation source of 100,000 Ci

    NASA Astrophysics Data System (ADS)

    Lombardo, J. H.; Smolko, E. E.

    A project for the production of radiovaccines and other bio-medical products is presented which includes a radiation facility provided with a gamma ray source equivalent to 100,000 Ci of Co-60. The whole process incorporates novel basic features in virus production and inactivation steps. The former is carried out in animals previously subjected to immunodepression through electromagnetic radiation. The later is obtained at low temperatures by using either electromagnetic or particle radiations. A vaccine manufacture process is shown to illustrate the utilization of ionizing radiations to obtain a foot and mouth disease virus (FMDV) vaccine with good antigenic quality and low cost.

  12. Terpolymerization of ethylene, sulfur dioxide and carbon monoxide

    DOEpatents

    Johnson, R.; Steinberg, M.

    This invention relates to high molecular weight terpolymer of ethylene, sulfur dioxide and carbon monoxide stable to 280/sup 0/C and containing as little as 36 mo1% ethylene and about 41 to 51 mo1% sulfur dioxide, and to the method of producing said terpolymer by irradiation of a liquid and gaseous mixture of ethylene, sulfur dioxide and carbon monoxide by means of Co-60 gamma rays or an electron beam, at a temperature of about 10 to 50/sup 0/C, and at a pressure of about 140 to 680 atmospheres, to initiate polymerization.

  13. Prediction of ionizing radiation effects induced performance degradation in homodyne BPSK based inter-satellite optical communication systems

    NASA Astrophysics Data System (ADS)

    Liu, Yun; Zhao, Shanghong; Gong, Zizheng; Zhao, Jing; Li, Xuan; Dong, Chen

    2016-03-01

    Ionizing radiation effects induced on-orbit performance degradation in homodyne binary phase shift keying (BPSK) based inter-satellite optical communication system is predicted in this paper. Essential optoelectronic devices involved in optical communication system were irradiated by Co60 gamma ray and ionizing radiation environment of three general orbits was analyzed. On this basis, variations of terminal performance loss and system BER degradation along with on-orbit working time were simulated. Influences of terminal location and orbit environment were further discussed. Radiation protection on laser transmitters requires more strengthening, especially for those located in MEO and GEO satellites.

  14. Preliminary pathway analysis for YMP preclosure biosphere dose assessment

    SciTech Connect

    Wu, D.; Liu, N.; Tappen, J.J.; Tung, C.H.

    1998-05-13

    The preliminary preclosure biosphere dose assessment for the Yucca Mountain Project (YMP) involves the calculation of a radiation dose to a subsistence farmer living near the proposed Yucca Mountain repository. Eight radionuclides, H-3, Co-60, Kr-85, Sr-90, Ru-106, I-129, Cs-134, and Cs-137, are considered in this study. Radiation doses resulting from unit release rates of these radionuclides are analyzed. Total dose has been broken down into components that result from various exposure pathways. By using this approach, the most important pathways that deliver a radiation dose to a subsistence farmer can be clearly identified.

  15. Is Radiosensitivity Associated to Different Types of Blood Groups? (A cytogenetic study)

    PubMed Central

    Elahimanesh, Farideh; Shabestani Monfared, Ali; Khosravifarsani, Meysam; Akhavan Niaki, Haleh; Abedian, Zeinab; Hajian-Tilaki, Karimollah; Borzouisileh, Sajad; Seyfizadeh, Nayer; Amiri, Mehrangiz

    2013-01-01

    Many biological factors affect radiosensitivity. In this study, radiosensitivity among the different blood groups was investigated. Peripheral blood sample of 95 healthy people were divided into two parts. One part was irradiated with 2 Gy Co-60 gamma rays and the second one was considered as control. Then all the samples were studied by cytokinesis-blocked micronucleus assay (CBMN assay). Our study showed that the radiosensitivity index of A+ and O+ groups was significantly higher and lower than other blood groups, respectively. It seems that blood type can be used as a radiosensitivity index for determining the given dose to radiotherapy, although extensive studies are necessary. PMID:24551803

  16. Biological changes observed on rice and biological and genetic changes observed on tabacco after space flight in the orbital station SALYUT-7 (Biobloc III experiment)

    NASA Astrophysics Data System (ADS)

    Bayonove, J.; Burg, M.; Mir, A.; Delpoux, M.

    Caryopses and isolated embryos from Rice (Oryza sativa L.) and Tobacco seeds (Nicotiana tabacum L. variety Xanthi) were studied in the Biobloc III container aboard the Soviet orbital space station SALYUT 7. The recovery from radiation damage under conditions of space flight was observed for rice caryopsis and embryos gamma irradiated (Co 60, 50 grays) prior to launch. There was a large decrease in the percentage of germinating seeds from the Tobacco strain tested when the seeds were exposed to heavy ions. Among the germinating plantlets there were few morphological anomalies. Furthermore, there was a significant greater amount of genetic change in those samples held in grids as compared to those in bags.

  17. Effects of 1-MeV gamma radiation on a multi-anode microchannel array detector tube

    NASA Technical Reports Server (NTRS)

    Timothy, J. G.; Bybee, R. L.

    1979-01-01

    A multianode microchannel array (MAMA) detector tube without a photocathode was exposed to a total dose of 1,000,000 rads of 1-MeV gamma radiation from a Co-60 source. The high-voltage characteristic of the microchannel array plate, average dark count, gain, and resolution of pulse height distribution characteristics showed no degradation after this total dose. In fact, the degassing of the microchannels induced by the high radiation flux had the effect of cleaning up the array plate and improving its characteristics.

  18. Growth-promotion of plants with depolymerized alginates by irradiation

    NASA Astrophysics Data System (ADS)

    Hien, Nguyen Quoc; Nagasawa, Naotsugu; Tham, Le Xuan; Yoshii, Fumio; Dang, Vo Huy; Mitomo, Hiroshi; Makuuchi, Keizo; Kume, Tamikazu

    2000-07-01

    Alginate has been degraded by gamma-ray irradiation from a Co-60 source in liquid state (aqueous solution) and in solid state (powder form). The irradiated alginate with a molecular weight less than 10 4 shows a strong effect on the growth-promotion of rice and peanut. Low concentration of degraded alginate from 4% solution irradiated at 100 kGy is effective for the growth-promotion of plants and the suitable concentrations are ca 50 ppm for rice and ca 100 ppm for peanut.

  19. Gamma ray spectrometry of LDEF samples at SRL

    NASA Technical Reports Server (NTRS)

    Winn, Willard G.

    1992-01-01

    A total of 31 samples from the Long Duration Exposure Facility (LDEF), including materials of aluminum, vanadium, and steel trunnions were analyzed by ultra-low-level gamma spectrometry. The study quantified particle induced activations of Na-22, Sc-46, Cr-51, Mn-54, Co-56, Co-57, Co-58, and Co-60. The samples of trunnion sections exhibited increasing activity toward the outer end of the trunnion and decreasing activity toward its radial center. The trunnion sections did not include end pieces, which were reported to collect noticeable Be-7 on their leading surfaces. No significant Be-7 was detected in the samples analyzed.

  20. Dependence of the spectral properties of alkaline-free alumino-phosphate glasses on chemical changes during synthesis

    SciTech Connect

    Antonenko, N.I.; Abdrashitova, E.I.; Artomova, M.V.

    1986-07-01

    In order to obtain information about glass microstructure within the first coordination sphere, glasses are irradiated with ionizing radiation. Doses of gamma-radiation not exceeding 10/sup 4/-10/sup 5/ Gy generally produce paramagnetic (PO/sub 4/)/sup 2 -/ radicals and more rarely (PO/sub 3/)/sup 2 -/ in phosphate glasses. This paper shows that in glasses of the same composition structural units of the same composition can exist, but with different chemical bonding depending on the chemical changes occurring during synthesis. Glass samples and batches were irradiated with a Co 60 source at room temperature and the ses were 10/sup 4/ Gy.

  1. Gamma radiation effects on the dynamic fatigue measurements of glass discs

    NASA Technical Reports Server (NTRS)

    Ananaba, T. O. J.; Kinser, D. L.

    1985-01-01

    Circular specimens of low iron soda lime silicate glass were blasted with grit after having a circular notch etched into their centers. After separation into two groups, one group was exposed to gamma radiation. The fracture strengths of all samples were then tested by the biaxial technique, i.e., specimens were balanced on three balls and loaded in the center by a piston. The irradiated samples had received a 140,000 Gy dose from a Co-60 source. An enhanced interaction between the ambient moisture and the grit-blasted central notch was observed in the irradiated samples, which displayed accelerated corrosion.

  2. Wastewater treatment using gamma irradiation: Tétouan pilot station, Morocco

    NASA Astrophysics Data System (ADS)

    Tahri, Loubna; Elgarrouj, Driss; Zantar, Said; Mouhib, Mohamed; Azmani, Amina; Sayah, Fouad

    2010-04-01

    The increasing demand on limited water supplies has accelerated the wastewater reuse and reclamation. We investigated gamma irradiation effects on wastewater by measuring differences in the legislated parameters, aiming to reuse the wastewater. Effluents samples were collected at the urban wastewater treatment station of Tetouan and were irradiated at different doses ranging from 0 to 14 kGy using a Co 60 gamma source. The results showed an elimination of bacterial flora, a decrease of biochemical and chemical oxygen demand, and higher conservation of nutritious elements. The results of this study indicated that gamma irradiation might be a good choice for the reuse of wastewater for agricultural activities.

  3. Present status of corn grain disinfestation by irradition in Mexico

    NASA Astrophysics Data System (ADS)

    Adem, E.; Uribe, R. M.; Watters, F. L.; Bourges, H.

    Progress in the use of ionizing radiation for the disinfestation of grain in Mexico is reviewed. Main topics described in the paper concern determination of optimum dose for disinfestation, comparison of Co-60 gamma rays and accelerated electrons for suppressing infestation, susceptibility of different strains of insects, dose rate effects on survival of different insect species, survival of progeny of irradiated insects, germinative tests, and effect of radiation on the nutrient content of corn. The technical and economical aspects of irradiation disinfestation is mentioned.

  4. The changes in optical absorbance of ZrO2 thin film with the rise of the absorbed dose

    NASA Astrophysics Data System (ADS)

    Abayli, D.; Baydogan, N.

    2016-03-01

    In this study, zirconium oxide (ZrO2) thin film samples prepared by sol-gel method were irradiated using Co-60 radioisotope as gamma source. Then, it was investigated the ionizing effect on optical properties of ZrO2 thin film samples with the rise of the absorbed dose. The changes in the optical absorbance of ZrO2 thin films were determined by using optical transmittance and the reflectance measurements in the range between 190 - 1100 nm obtained from PG Instruments T80 UV-Vis spectrophotometer.

  5. NASA/GSFC reliability evaluation of high temperature fiber optic cables

    NASA Technical Reports Server (NTRS)

    Sharma, A. K.; Jacobs, G.

    1992-01-01

    A high temperature (200 C rating) fiber-optic cable of fluorocarbon, silica-based glass, and polyimide coating, 100-micron core was evaluated for Goddard Space Flight Center applications. Testing was performed to evaluate attenuation characteristics of the cables during environmental stresses and exposure to Co-60 gamma radiation. The cables passed environmental tests, but after irradiation failed the established delta limit of 3 dB at 10 krads for a wavelength of 850 nm and 100 krads for a wavelength of 1300 nm.

  6. Development of a radiation-hard photomultiplier tube

    NASA Technical Reports Server (NTRS)

    Birnbaum, M. M.; Bunker, R. L.; Roderick, J.; Stephenson, K.

    1984-01-01

    In a radiation-hard photomultiplier tube (PMT) such as has been developed for stabilization of the Galileo spacecraft as it goes through the Jovian high energy radiation belts, the primary effects of high energy electron and proton radiation that must be resisted are the production of fluorescence and Cerenkov emission. The present PMT envelope is ceramic rather than glass, and employs a special, electron-focusing design which will collect, accelerate and amplify electrons only from desired photocathode areas. Tests in a Co-60 radiation facility have shown that the radiation-hard PMT produces less than 2.5 percent of the radiation noise of a standard PMT.

  7. Comparison of radiation damage parameter values for the widely used semiconductor gamma detector materials in wide energy range

    NASA Astrophysics Data System (ADS)

    Korkut, Turgay; Korkut, Hatun

    2014-04-01

    Number of displaced atoms (NDA) values for 3 different semiconductor detector materials (Ge, Si, and GaAs) was reviewed at 26 different primary energies emitted from 9 radiation sources (241Am, 133Ba, 109Cd, 57Co, 60Co, 137Cs, 152Eu, 55Fe and 153Gd) widely used in the literature. FLUKA Monte Carlo code was used to simulate interactions between X-gamma rays and semiconductor detector materials. Germanium has the highest average NDA value in the studied three semiconductors.

  8. Proliferation effect of He-Ne laser intermittent irradiation on mouse bone-marrow cells

    NASA Astrophysics Data System (ADS)

    Chen, Ji; Zhang, Jianjun

    1993-03-01

    The effect of He-Ne laser intermittent irradiation on the bone marrow cell suspension of donor mice is presented in this paper. The recipient mice, irradiated with 8.5 GY CO60-(gamma) ray, were then infused, and they were killed different days (1, 3, 5, 7, 9, and 11 days post injection). Spleens were removed and fixed in Bouin's solution for 24 hours, and then the numbers of protruding splenic nodules visible on the surface of the spleens were counted. According to statistics, the number of the splenic nodules increased with laser exposure over the control group.

  9. Effect of Planar Anisotropy in Vortex Configuration of Micro-scale Disks

    NASA Astrophysics Data System (ADS)

    Parreiras, S. O.; Martins, M. D.

    The magnetic configuration of micron-sized Co60Fe40 and Permalloy disks was investigated using micromagnetic simulations and magnetic force microscopy (MFM) measurements. By comparing both materials, it is possible to elucidate the effect of the planar magnetocrystaline anisotropy in the stability of the magnetic vortex configuration. The results for disks with diameters between 0.5 and 8 μm showed that the magnetic anisotropy favors spins alignment and domains division, reducing vortex stability. Different magnetic configurations was observed for each disk diameter. Additionally, a statistical analysis of the magnetic configuration distribution experimentally observed by MFM was performed and compared with the simulation results.

  10. General data analysis code for TDCR liquid scintillation counting.

    PubMed

    Rodrigues, D; Arenillas, P; Capoulat, M E; Balpardo, C

    2008-01-01

    A non-radionuclide-specific computer code to analyze data, calculate detection efficiency and activity in a TDCR system is presented. The program was developed prioritizing flexibility in measuring conditions, parameters and calculation models. It is also intended to be well structured in order to easily replace subroutines which could eventually be improved by the user. It is written in standard FORTRAN language but a graphical interface is also available. Several tests were performed to check the ability of the code to deal with different decay schemes such as H-3, C-14, Fe-55, Mn-54 and Co-60. PMID:18356062

  11. Monitoring the fate of radionuclides released to the environment: May 1991 report

    SciTech Connect

    Bauer, L.R.

    1992-08-13

    A review of the radiological effluent and environmental monitoring practices in use at Mound has been conducted. The radionuclides under consideration were HT, Pu-239, U-233,234, U-238, Th-230, Th-232, Co-60, Cs-137, and Ac-227. It is concluded from this analysis that additional continuous monitoring programs are not warranted. Dose contributions from these radionuclides are negligible. Further, in many cases environmental surveillance would not be practical due to the extremely low concentrations encountered in the offsite environment. For these reasons, it is believed that no additional action is required in response to DOE Tiger Team Finding R/CF-1.

  12. Performance degradation of QAM based inter-satellite optical communication system under gamma irradiation

    NASA Astrophysics Data System (ADS)

    Liu, Yun; Zhao, Shanghong; Gong, Zizheng; Zhao, Jing; Li, Xuan

    2016-01-01

    Main devices in quadrature amplitude modulation (QAM) based inter-satellite optical communication system were irradiated to a total dose of 20 krad with the dose rate of 5 rad/s using a Co60 radiation source. Gamma irradiation impacts on devices were analyzed and on the basis, system performance degradation was simulated. Variety of system BER along with onboard working time for different inter-satellite links was presented. In addition, some adaption methods were proposed to reduce gamma irradiation induced degradation.

  13. Radiation vulcanization of natural rubber latex with polyfunctional monomers

    SciTech Connect

    Makuuchi, K.; Hagiwara, M.

    1984-03-01

    Natural rubber latex was irradiated with ..gamma..-rays from Co-60 in the presence of polyfunctional monomers to accelerate crosslinking of rubber molecules. Hydrophobic monomers were more effective in accelerating the vulcanization than were hydrophilic monomers. This was ascribed to high solubility of hydrophobic monomers in rubber particles. Among the hydrophobic monomers, neopentylglycol dimethacrylate (NPG) exhibited the highest efficiency in accelerating the vulcanization. Advantages of using NPG are high colloidal stability of the irradiated latex and high thermal stability of dried rubber film.

  14. Grafting of thermo-sensitive N-vinylcaprolactam onto silicone rubber through the direct radiation method

    NASA Astrophysics Data System (ADS)

    Valencia-Mora, Ricardo A.; Zavala-Lagunes, Edgar; Bucio, Emilio

    2016-07-01

    The modification of silicone rubber films (SR) was performed by radiation-induced graft polymerization of thermosensitive poly(N-vinylcaprolactam) (PNVCL) using gamma rays from a Co-60 source. The graft polymerization was obtained by a direct radiation method with doses from 5 to 70 kGy, at monomer concentrations between 5% and 70% in toluene. Grafting was confirmed by infrared, differential scanning calorimetry, thermogravimetric analysis, and swelling studies. The lower critical solution temperature (LCST) of the grafted SR was measured by swelling and differential scanning calorimetry.

  15. Al-26: A galactic source of gamma ray line emission

    NASA Technical Reports Server (NTRS)

    Ramaty, R.; Lingenfelter, R. E.

    1976-01-01

    It is shown that Al26 is a very good candidate for producing a detectable gamma-ray line, and that this line is not only intense but also very narrow. By examining the chart of nuclides for other radioactive isotopes which could produce hiterto unnoticed gamma-ray lines following nucleosynthesis, it is found that for mass numbers less than 60, the isotopes Na22, Al26, K40, Ar42, Ti44, Sc46, Mn54, Co56, Co57, Co58, Co60 and Fe60 are the only ones with sufficiently long half lives (70) days to produce gamma rays in optically thin regions.

  16. An investigation of aluminum titanate-spinel composites behavior in radiation

    SciTech Connect

    Cevikbas, G.; Tugrul, A. B.; Boyraz, T.; Buyuk, B.; Onen, U.

    2015-03-30

    In the present work, the radiation attenuation properties of Aluminum titanate (Al{sub 2}TiO{sub 5})-Spinel (MgAl{sub 2}O{sub 4}) ceramics composites were investigated. Al{sub 2}TiO{sub 5}-MgAl{sub 2}O{sub 4} ceramics composites which have different Al{sub 2}TiO{sub 5} percentages (0%, 5% and 10%) were produced and performed against gamma sources. Cs-137 and Co-60 were used as gamma radiation sources. Transmission technique was used in the experiments. The linear and mass attenuation coefficients of the samples were carried out for gamma radiation sources. The experimental results were compared with the theoretical mass attenuation coefficients which were calculated by using XCOM computer code. Increasing Al{sub 2}TiO{sub 5} percentage in the Aluminum titanate/ Spinel ceramics composites causes the higher linear and mass attenuation coefficients of the composites against Cs-137 and Co-60 gamma radioisotopes. Therefore Also theoretical mass attenuation coefficients are compatible with the experimental results. In conclusion, increasing the Aluminum titanate ratio in the Al{sub 2}TiO{sub 5}-MgAl{sub 2}O{sub 4} ceramics composites increases the gamma shielding property of the Al{sub 2}TiO{sub 5}-MgAl{sub 2}O{sub 4} ceramics for nuclear shielding applications.

  17. SU-E-T-265: Presage Thin Sheet Dosimeter Characterization

    SciTech Connect

    Dumas, M; Rakowski, J

    2014-06-01

    Purpose: To quantify the sensitivity and stability of the Presage dosimeter in sheet form for different concentrations of chemicals and for a diverse range of clinical photon energies. Methods: Presage polymer dosimeters are formulated to investigate and optimize their sensitivity and stability. The dosimeter is composed of clear polyurethane base, leucomalachite green reporting dye, and bromoform radical initiator in 1mm thick sheets. The chemicals are well mixed together, cast in an aluminum mold, and left to cure at 60 psi for a minimum of 2 days. Dosimeter response will be characterized at multiple energies including Co-60, 6 MV, 15 MV, 50 kVp, and 250 kVp. The dosimeters are read by an Epson 10000 XL scanner at 800 dpi, 2{sup 16} bit depth. Red component images are analyzed with ImageJ. Results: Analysis of optical density verse dose for Co-60 energies indicates that the bromoform containing Presage was able to quantify dose from 0 to 300 Gy, with saturation beyond 300 Gy. Initial results show two regions of linear response, 0–100 Gy and 150–300 Gy. The 150–300 Gy region has a sensitivity of 0.0024 net OD/Gy. Further results on other energies are still in progress. Conclusions: This work shows the potential for use of thin sheets of Presage dosimeter as a dosimeter capable of being analyzed with a flatbed scanner.

  18. Conditions of the cosmic ray exposure of the Jilin chondrite

    NASA Astrophysics Data System (ADS)

    Heusser, G.; Ouyang, Z.; Kirsten, T.; Herpers, U.; Englert, P.

    1985-02-01

    Nine documented samples from the main mass, Jilin 1, and three samples from different locations of the strewn field have been analyzed for cosmogenic Al-29 (T-1/2 = 0.716 Myr), Co-60 (T-1/2 = 5.27 yr) and Na-22 = 2.6 yr). Mn-53 (T-1/2 = 3.7 Myr) has been determined in seven of the same documented samples and in two further documented samples. The preatmospheric size of Jilin was reconstructed from the documented sample positions and from the measured Co-60 activites. Jilin was almost spherical and had a preatmospheric radius of about 85 cm. The cosmogenic nuclides in Jilin can be explained by a two-stage exposure history. The first stage occurred near the surface of the parent body in 2-Pi geometry and lasted about 10 Myr. Jilin was then expelled from its parent body and exposed to cosmic rays in a second (4-Pi) stage lasting approximately 0.4 Myr. The measured concentration profiles of spallogenic nuclides are compared to calculated production rates.

  19. Study on antibacterial activity of silver nanoparticles synthesized by gamma irradiation method using different stabilizers

    NASA Astrophysics Data System (ADS)

    Van Phu, Dang; Quoc, Le Anh; Duy, Nguyen Ngoc; Lan, Nguyen Thi Kim; Du, Bui Duy; Luan, Le Quang; Hien, Nguyen Quoc

    2014-04-01

    Colloidal solutions of silver nanoparticles (AgNPs) were synthesized by gamma Co-60 irradiation using different stabilizers, namely polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA), alginate, and sericin. The particle size measured from TEM images was 4.3, 6.1, 7.6, and 10.2 nm for AgNPs/PVP, AgNPs/PVA, AgNPs/alginate, and AgNPs/sericin, respectively. The influence of different stabilizers on the antibacterial activity of AgNPs was investigated. Results showed that AgNPs/alginate exhibited the highest antibacterial activity against Escherichia coli ( E. coli) among the as-synthesized AgNPs. Handwash solution has been prepared using Na lauryl sulfate as surfactant, hydroxyethyl cellulose as binder, and 15 mg/L of AgNPs/alginate as antimicrobial agent. The obtained results on the antibacterial test of handwash for the dilution to 3 mg AgNPs/L showed that the antibacterial efficiency against E. coli was of 74.6%, 89.8%, and 99.0% for the contacted time of 1, 3, and 5 min, respectively. Thus, due to the biocompatibility of alginate extracted from seaweed and highly antimicrobial activity of AgNPs synthesized by gamma Co-60 irradiation, AgNPs/alginate is promising to use as an antimicrobial agent in biomedicine, cosmetic, and in other fields.

  20. Modification of fecundity and fertility during oogenesis by. gamma. radiation and/or ozone with a cytological analysis in the ectoparasitic wasp, Habrobracon juglandis (Ashmead)

    SciTech Connect

    Ofuoku, E.E.

    1984-01-01

    In Experiment I, adult female wasps were exposed to ozone for 0, 2, 4, 6, 8, 10, 12, 16, 24, and 27 h. The results indicated that the 27 h of ozone exposure produced 100% lethality on the first day. Exposures below 27 h progressively decreased life span with increasing length of exposure. In Experiment II A, adult virgin Habrobracon females were exposed to ozone for 0, 2, 4, 6, 8, 10, 12, 16, and 24 h to determine the effects of ozone on fecundity (egg laying ability) and fertility (egg hatching ability). The results showed that ozone significantly decreased fecundity and fertility in all meiotic stages except metaphase I. In Experiment II B, adult virgin Habrobracon females were exposed to Co-60 ..gamma.. radiation. All treated wasps showed significant progressive decreases in fecundity and fertility with increases in radiation dose. In Experiment II C, adult virgin Habrobracon females were exposed to Co-60 ..gamma.. radiation, to ozone, or to combinations thereof to determine the effects of these insults on fecundity and fertility. Together or singly ozone and radiation reduced fecundity and fertility. In Experiment III, adult virgin Habrobracon females were exposed to the conditions of Experiment II C to correlate by cytological examination of the ovarioles the effects of ionizing radiation and/or ozone on the germ cells at specific meiotic stages. Results obtained from the cytological study explain the fecundity and fertility observations.

  1. Morphometric studies of heavy ion damage in the brains of rodents

    NASA Technical Reports Server (NTRS)

    Kraft, L. M.; Cox, A. B.

    1986-01-01

    The relative biological effectiveness (RBE) of different heavy ions for the mammalian brain was determined in mice irradiated at 100 days of age with He-4, C-12, Ne-20, Fe-56, Ar-40, or Co-60 gamma photons (with the primary particle LET values ranging from 2 to 650). Brain preparations were examined 16 months later for volume changes in the external plexiform layer (P-zone) of the olfactory bulb and an internal region (G-zone), which consists of the granule cells, the internal plexiform layer, and the mitral cell layer. The result indicate that the volume changes did occur in the olfactory bulb, not only in absolute terms but also when expressed as the ratio of the structures to each other and to the bulb as a whole. While the observed increased neuronal loss in mice receiving 700 cGy of Co-60 support the earlier data from irradiated rabbits, the increases observed in bulbar volumes and in the volume ratios of the P and the G zones measured in the mice given lower doses (320 or 160 cGy of He or C), were not expected.

  2. An investigation on gamma attenuation behaviour of titanium diboride reinforced boron carbide-silicon carbide composites

    NASA Astrophysics Data System (ADS)

    Buyuk, Bulent; Beril Tugrul, A.

    2014-04-01

    In this study, titanium diboride (TiB2) reinforced boron carbide-silicon carbide composites were investigated against Cs-137 and Co-60 gamma radioisotope sources. The composite materials include 70% boron carbide (B4C) and 30% silicon carbide (SiC) by volume. Titanium diboride was reinforced to boron carbide-silicon carbide composites as additive 2% and 4% by volume. Average particle sizes were 3.851 µm and 170 nm for titanium diboride which were reinforced to the boron carbide silicon carbide composites. In the experiments the gamma transmission technique was used to investigate the gamma attenuation properties of the composite materials. Linear and mass attenuation coefficients of the samples were determined. Theoretical mass attenuation coefficients were calculated from XCOM computer code. The experimental results and theoretical results were compared and evaluated with each other. It could be said that increasing the titanium diboride ratio causes higher linear attenuation values against Cs-137 and Co-60 gamma radioisotope sources. In addition decreasing the titanium diboride particle size also increases the linear and mass attenuation properties of the titanium diboride reinforced boron carbide-silicon carbide composites.

  3. An investigation of aluminum titanate-spinel composites behavior in radiation

    NASA Astrophysics Data System (ADS)

    Cevikbas, G.; Tugrul, A. B.; Onen, U.; Boyraz, T.; Buyuk, B.

    2015-03-01

    In the present work, the radiation attenuation properties of Aluminum titanate (Al2TiO5)-Spinel (MgAl2O4) ceramics composites were investigated. Al2TiO5-MgAl2O4 ceramics composites which have different Al2TiO5 percentages (0%, 5% and 10%) were produced and performed against gamma sources. Cs-137 and Co-60 were used as gamma radiation sources. Transmission technique was used in the experiments. The linear and mass attenuation coefficients of the samples were carried out for gamma radiation sources. The experimental results were compared with the theoretical mass attenuation coefficients which were calculated by using XCOM computer code. Increasing Al2TiO5 percentage in the Aluminum titanate/ Spinel ceramics composites causes the higher linear and mass attenuation coefficients of the composites against Cs-137 and Co-60 gamma radioisotopes. Therefore Also theoretical mass attenuation coefficients are compatible with the experimental results. In conclusion, increasing the Aluminum titanate ratio in the Al2TiO5-MgAl2O4 ceramics composites increases the gamma shielding property of the Al2TiO5-MgAl2O4 ceramics for nuclear shielding applications.

  4. The Next Generation Air Particle Detectors for the United States Navy

    SciTech Connect

    Robert Hayes and Craig Marianno

    2007-06-24

    Design and testing of the United States Navy’s next generation air particle detector (NGAPD) is presently underway. The NGAPD is intended for use in nuclear applications for the United States Navy and is being designed to detect airborne Co-60 with a reduction in false alarms and improved ease of use. Features being developed include gamma compensation, low maintenance, commercial off-the-shelf electronics, and spectrum simulation for quality assurance and functional testing applications. By supplying a spectrum simulator, the radon stripping algorithm can be running when a simulated anthropogenic source spectrum (e.g., from Co-60 or transuranics) is superimposed on the radon progeny spectrum. This will allow alarm levels to be tested when the air flow is running and the radon stripping algorithm is providing the instrument response output. Modern units evaluate source spectra with the air flow off and the radon spectrum absent thereby not testing the true system performance which comes out of the radon stripping algorithm. Testing results of the preliminary prototype show promise along with computer simulations of source spectra. Primary testing results taken to date include gamma compensation, thermal insults, vibration and spectrum simulation.

  5. Brief rapid thermal treatment effect on patterned CoFeB-based magnetic tunneling junctions

    NASA Astrophysics Data System (ADS)

    Wu, Kuo-Ming; Huang, Chao-Hsien; Wang, Yung-Hung; Kao, Ming-Jer; Tsai, Ming-Jinn; Wu, Jong-Ching; Horng, Lance

    2007-05-01

    The brief thermal treatment effects on the magnetoresistance of microstructured Co60Fe20B20-based magnetic tunneling junctions have been studied. The elliptical shape of devices with long/short axis of 4/2μm was patterned out of film stack of seed layer (20)/PtMn(15)/Co60Fe20B20(3)/Al(0.7)oxide/C60Fe20B20(20)/capping layer (48) (thickness unit in nanometers) combining conventional lithography and inductively coupled plasma reactive ion beam etching technologies. The thermal annealing was carried out with device loading into a furnace with preset temperatures ranging from 100to400°C for only 5min in the absence of any external magnetic field. The magnetoresistance was found to increase with increasing annealing temperatures up to 250°C and then decrease at higher annealing temperatures. In addition, the magnetoresistance ratio of around 35%, similar to that of as-fabricated devices, sustains up to annealing temperature of 350°C. This survival of magnetoresistance at higher annealing temperature is due to boron conservation in the amorphous CoFeB ferromagnetic layer at higher annealing temperature for only a short time, which is manifested using x-ray diffractometer technique.

  6. Radiation defects and energy storage in natural polycrystalline rock salt. Results of an in-situ test in the Permian rock salt of the Asse

    SciTech Connect

    Gies, H.; Rothfuchs, T.; Celma, A.G.; Haas, J.B.M. de; Pederson, L.

    1994-12-31

    Radiation damage development and the corresponding energy storage in pure undeformed single crystals have frequently been studied in laboratory experiments, however little is known of irradiation experiments on natural rock salt (polycrystalline, deformed and impure) under geological conditions. The relevance of these parameters to the defect formation was revealed by a joint United States/Federal Republic of Germany in-situ test in the Asse Mine. Natural rock salt was heated and irradiated using Co-60 sources. Calculations of the amount of halite expected to be decomposed by radiolysis during the experiment were performed using the 1985 version of the Jain-Lidiard model. Qualitative agreement between theory and analyses was found for all the performed analyses. Quantitative and qualitative deviations of the natural samples behaviour from that of single undeformed crystals were observed and attributed to the influence of sulfatic admixtures, polycrystallinity and strain on radiation damage development and anneal. Special chemical methods, such as iodometric titration and uv-visible spectroscopy were applied in order to measure the hypochlorite ion, which forms in irradiated salt. Composite samples located closet to the Co-60 source averaged 0,4 micromoles neutral chlorine atoms per gram salt, a factor of two more than from other positions. Uv-vis analyses revealed more than a factor of ten greater neutral chlorine concentrations in coloured halite. Similarly, optical absorption measurements indicated a factor of ten difference in sodium metal colloid concentrations.

  7. Immobilization of the Radionuclides from Spent Ion-Exchange Resins Using Vitrification

    SciTech Connect

    Hutson, N. D.; Crawford, C. L.; Russo, D. O.; Sterba, M. E.

    2002-02-25

    Approximately 60 g of an iron-enriched borosilicate glass was made in the radiochemical labs of the Savannah River Technology Center (SRTC). The glass was made to demonstrate the immobilization of the radioisotopes contained on representative Argentine ion exchange resins (similar to those used at the Embalse plant). The product was approximately 90% amorphous and was quite durable as measured by the release rates from the Product Consistency Test (PCT). The release rates were considerably better than those of the U. S. High Level Waste (HLW) benchmark DWPF EA glass. The release rate of the Cs-137 was predictably similar to that of Na and Li. No Co-60 or Sr-90 was measured in the PCT leachate. The mass balances for the inactive additives were quite good. Of the radioisotopes, approximately 71% of Cs-137 was accounted for in the glass product. This was similar to the Na mass balance. Approximately 89% of the Co-60 was accounted for in the glass product.

  8. Radiation effects in LDD MOS devices

    SciTech Connect

    Woodruff, R.L.; Adams, J.R.

    1987-12-01

    The purpose of this work is to investigate the response of lightly doped drain (LDD) n-channel transistors to ionizing radiation. Transistors were fabricated with conventional (non-LDD) and lightly doped drain (LDD) structures using both standard (non-hardened) and radiation hardened gate oxides. Characterization of the transistors began with a correlation of the total-dose effects due to 10 keV x-rays with Co-60 gamma rays. The authors find that for the gate oxides and transistor structures investigated in this work, 10 keV x-rays produce more fixed-charge guild-up in the gate oxide, and more interface charge than do Co-60 gamma rays. They determined that the radiation response of LDD transistors is similar to that of conventional (non-LDD) transistors. In addition, both standard and radiation-hardened transistors subjected to hot carrier stress before irradiation show a similar radiation response. After exposure to 1.0 x 10/sup 6/ rads(Si), non-hardened transistors show increased susceptibility to hot-carrier graduation, while the radiation-hardened transistors exhibit similar hot-carrier degradation to non-irradiated devices. The authors have demonstrated a fully-integrated radiation hardened process tht is solid to 1.0 x 10/sup 6/ rads(Si), and shows promise for achieving 1.0 x 10/sup 7/ rad(Si) total-dose capability.

  9. Reprocessing technology development for irradiated beryllium

    SciTech Connect

    Kawamura, H.; Sakamoto, N.; Tatenuma, K.

    1995-09-01

    At present, beryllium is under consideration as a main candidate material for neutron multiplier and plasma facing material in a fusion reactor. Therefore, it is necessary to develop the beryllium reprocessing technology for effective resource use. And, we have proposed reprocessing technology development on irradiated beryllium used in a fusion reactor. The preliminary reprocessing tests were performed using un-irradiated and irradiated beryllium. At first, we performed beryllium separation tests using un-irradiated beryllium specimens. Un-irradiated beryllium with beryllium oxide which is a main impurity and some other impurities were heat-treated under chlorine gas flow diluted with Ar gas. As the results high purity beryllium chloride was obtained in high yield. And it appeared that beryllium oxide and some other impurities were removed as the unreactive matter, and the other chloride impurities were separated by the difference of sublimation temperature on beryllium chloride. Next, we performed some kinds of beryllium purification tests from beryllium chloride. And, metallic beryllium could be recovered from beryllium chloride by the reduction with dry process. In addition, as the results of separation and purification tests using irradiated beryllium specimens, it appeared that separation efficiency of Co-60 from beryllium was above 96%. It is considered that about 4% Co-60 was carried from irradiated beryllium specimen in the form of cobalt chloride. And removal efficiency of tritium from irradiated beryllium was above 95%.

  10. Study for radionuclide transfer ratio of aerosols generated during heat cutting

    SciTech Connect

    Iguchi, Yukihiro; Baba, Tsutomu; Kawakami, Hiroto; Kitahara, Takashi; Watanabe, Atsushi; Kodama, Mitsuhiro

    2007-07-01

    The metallic elements with a low melting point and high vapor pressure seemed to transfer in aerosols selectively at dismantling reactor internals using heat cutting. Therefore, the arc melting tests of neutron irradiated zirconium alloy were conducted to investigate the radionuclide transfer behavior of aerosols generated during the heat cutting of activated metals. The arc melting test was conducted using a tungsten inert gas welding machine in an inert gas or air atmosphere. The radioactive aerosols were collected by filter and charcoal filter. The test sample was obtained from Zry-2 fuel cladding irradiated in a Japanese boiling water reactor for five fuel cycles. The activity analysis, chemical composition measurement and scanning electron microscope observation of aerosols were carried out. Some radionuclides were enriched in the aerosols generated in an inert gas atmosphere and the radionuclide transfer ratio did not change remarkably by the presence of air. The transfer ratio of Sb-125 was almost the same as that of Co-60. It was expected that Sb-125 was enriched from other elements since Sb is an element with a low melting point and high vapor pressure compared with the base metal (Zr). In the viewpoint of the environmental impact assessment, it became clear that the influence if Sb-125 is comparable to Co-60. The transfer ratio of Mn-54 was one order higher compared with other radionuclides. The results were discussed on the basis of thermal properties and oxide formation energy of the metallic elements. (authors)

  11. Comparison between planar magnetocrystaline and shape anisotropies in the magnetic vortex configuration of nanostructured particles

    NASA Astrophysics Data System (ADS)

    Parreiras, Sofia; Souza, Rafael; Martins, Maximiliano

    2015-03-01

    Soft ferromagnetic dots with sub-micrometer size can exhibit in the ground state a curling spin configuration known as magnetic vortex. In the case of soft ferromagnetic materials in micron and submicron scales, small changes in shape, size and material's anisotropy can modify the energy equilibrium that defines the stable spin structure. In this work, we investigated the magnetic configuration of micron-sized Co60Fe40 and Permalloy disks and elipses, prepared by lift-off lithography process, by comparing the results of micromagnetic simulations and magnetic force microscopy (MFM) measurements. By comparing the results for Co60Fe40 and Permalloy it is possible to elucidate the effect of the planar magnetocrystaline anisotropy in the stability of the magnetic vortex configuration and this effect is compared with the effect of the shape anisotropy induced by the elliptical shape. The results for disks with diameters between 0.5 and 8 μm showed that the anisotropy favors spins alignment and domains division, reducing vortex stability. The results showed different magnetic configurations for each disk diameter. Additionally, a statistical analysis of the magnetic configuration distribution observed in MFM experiments was performed and compared with the simulation results. Acknowledgements: CAPES, CNPq and FAPEMIG.

  12. Design, Development and Operational Experience of Demonstration Facility for Cs-137 Source Pencil Production at Trombay - 13283

    SciTech Connect

    Patil, S.B.; Srivastava, P.; Mishra, S.K.; Khan, S.S.; Nair, K.N.S.

    2013-07-01

    Radioactive waste management is a vital aspect of any nuclear program. The commercial feasibility of the nuclear program largely depends on the efficiency of the waste management techniques. One of such techniques is the separation of high yield radio-nuclides from the waste and making it suitable for medical and industrial applications. This will give societal benefit in addition to revenue generation. Co-60, the isotope presently being used for medical applications, needs frequent replacement because of its short half life. Cs-137, the major constituent of the nuclear waste, is a suitable substitute for Co-60 as a radioactive source because of its longer half life (28 years). Indian nuclear waste management program has given special emphasis on utilization of Cs-137 for such applications. In view of this a demonstration facility has been designed for vitrification of Cs-137 in borosilicate glass, cast in stainless steel pencils, to be used as source pencils of 300 Ci strength for blood irradiation. An induction heated metallic melter of suitable capacity has been custom designed for the application and employed for the Cs-137 pencil fabrication facility. This article describes various systems, design features, experiments and resulting modifications, observations and remote handling features necessary for the actual operation of such facility. The layout of the facility has been planned in such a way that the same can be adopted in a hot cell for commercial production of source pencils. (authors)

  13. A CMOS matrix for extracting MOSFET parameters before and after irradiation

    NASA Technical Reports Server (NTRS)

    Blaes, B. R.; Buehler, M. G.; Lin, Y.-S.; Hicks, K. A.

    1988-01-01

    An addressable matrix of 16 n- and 16 p-MOSFETs was designed to extract the dc MOSFET parameters for all dc gate bias conditions before and after irradiation. The matrix contains four sets of MOSFETs, each with four different geometries that can be biased independently. Thus the worst-case bias scenarios can be determined. The MOSFET matrix was fabricated at a silicon foundry using a radiation-soft CMOS p-well LOCOS process. Co-60 irradiation results for the n-MOSFETs showed a threshold-voltage shift of -3 mV/krad(Si), whereas the p-MOSFETs showed a shift of 21 mV/krad(Si). The worst-case threshold-voltage shift occurred for the n-MOSFETs, with a gate bias of 5 V during the anneal. For the p-MOSFETs, biasing did not affect the shift in the threshold voltage. A parasitic MOSFET dominated the leakage of the n-MOSFET biased with 5 V on the gate during irradiation. Co-60 test results for other parameters are also presented.

  14. Una Guia para Los Padres sobre La Educacion Especial: El Derecho de Su Hijo(a) a Adquirir una Educacion en el Estado de Nueva York (A Parent's Guide to Special Education: Your Child's Right to an Education in New York State).

    ERIC Educational Resources Information Center

    New York State Education Dept. Albany. Office for the Education of Children with Handicapping Conditions.

    This guide provides information to help parents of special needs children in New York become active partners in the planning and implementation of special education programs. The first part of the guide provides in-depth information related to the special education process in New York State public schools. A historical view of children's rights to…

  15. Efectos Especiales de Anclaje (Estudio sobre Regresiones de Juicios Condicionales). Parte 1: Distincion entre Efectos Aditivos y Efectos Multiplicativos en el Fenomeno de Anclaje (Special Effects of Anchoring (Study on Regression of Conditional Judgements) Part 1: Distinction Between Additive Effects and Multiplicative Effects in the Phenomenon of Anchoring). Publication No. 17.

    ERIC Educational Resources Information Center

    Lopez Alonso, A. O.

    A linear relationship was found between judgements given by 160 subjects to 7 objects presented as single stimuli (alpha judgements) and judgements given to the same objects presented with a condition (gamma judgements). This relationship holds for alpha judgements and the gamma judgements that belong to a family of constant stimulus and varying…

  16. What Providers Should Know about Child Care Assistance for Families: A Targeted Effort to Reach Hispanic Families and Providers = Lo que Deben Saber los Proveedores Sobre el Programa de Ayuda de Cuidado Infantil para las Familias: Un Esfuerzo Especial para Alcanzar Familias y Proveedores Hispanos

    ERIC Educational Resources Information Center

    Child Care Bureau, 2004

    2004-01-01

    Federal and State governments can help families pay for child care. The families one serves may be eligible for this assistance, and one may receive this funding for services one provides, thus becoming a "participating provider." This paper provides answers to the following questions: (1) How can parents receive child care assistance?; (2) How do…

  17. "Estudia para que no te pase lo que a mi": Narrativas Culturales Sobre el Valor de la Escuela en Familias Mexicanas ("Study So That What Happened to Me Doesn't Happen to You": Cultural Narratives about the Value of Schooling in Mexican Families).

    ERIC Educational Resources Information Center

    Ramos, Claudia Saucedo

    2003-01-01

    Narratives used by parents in Mexican working-class families to motivate their children to study are examined for the advice offered and parental attitudes about the importance of school. The integration of contemporary pressures about the value of schooling is investigated, as well as the ways in which the value of schooling is being…

  18. Que Tal la Justicia Social en los Alumnos de la UIA (Universidad Iberoamericana)? Investigacion sobre los Logros en la Formacion Valoral (What about Social Justice among the Students of the Iberoamerican University? Survey on the Achievements in the Acquisition of Values).

    ERIC Educational Resources Information Center

    Bazdresch Parada, Juan E.

    This survey investigates how the students of social philosophy modify their criteria on basic questions of social justice. A questionnaire of 30 questions, with 5 options, was developed. The five answer/options correspond to the following five schools of social philosophy (five ways of thinking): (1) liberal individualism; (2) humanitarianism; (3)…

  19. Identity-Forming Discourses: A Critical Discourse Analysis on Policy Making Processes Concerning English Language Teaching in Colombia (Discursos que forjan identidades: un análisis crítico de discursos en la formulación de políticas sobre la enseñanza del inglés en Colombia)

    ERIC Educational Resources Information Center

    Escobar Alméciga, Wilder Yesid

    2013-01-01

    This article addresses a critical problem about asymmetrical power relationships and uneven conditions in English language education exerted via identity shaping discourses in the document Educación: "Visión 2019" issued by the Colombian Ministry of National Education. The study follows the critical discourse analysis method. It…

  20. Lo que los educadores necesitan saber sobre...El agrupamiento por habilidad [y] La compactacion del curriculum [y] Los alumnos dotados y el aprendizaje cooperativo [y] La actividad tutoral. Guias practica (What Educators Need To Know about...Ability Grouping [and] Curriculum Compacting [and] Gifted Students and Cooperative Learning [and] Mentoring. Practitioners' Guides).

    ERIC Educational Resources Information Center

    Siegle, Del, Ed.

    These four pamphlets in Spanish offer guidelines supported by theory-driven quality research that is problem-based, practice-relevant, and consumer-oriented. Each pamphlet has a section summarizing research from the literature or topic notes as well as implications for the classroom. The first guide offers principles for teachers concerning the…

  1. Proyecto Curricular Sobre la Herencia Iberoamericana. Latinos en la Formacion de los Estados Unidos de American: Ayer, Hoy y Manana. Procedimientos de la Conferencia Sequnda Conferencia Anual del Panel Consultivo Internacional en Santillana del Mar, Espana (The Ibero-American Heritage Curriculum Project. Latinos in the Making of the United States of America: Yesterday, Today, and Tomorrow).

    ERIC Educational Resources Information Center

    New York State Education Dept., Albany.

    The Ibero-American Heritage Curriculum Project is an interdisciplinary curriculum development project designed to integrate the study of Ibero-American heritage and culture into classroom instructional programs, kindergarten through grade 12. The project was initiated by the New York State Education Department and involves the Spanish National…

  2. Using Case Study Methodology to Approach the Views of Teachers of English on Classroom Disciplinary Strategies (Uso de la metodología de estudio de casos para aproximarse a las concepciones de profesores de inglés sobre las estrategias disciplinarias en el aula)

    ERIC Educational Resources Information Center

    Díaz Larenas, Claudio

    2012-01-01

    This qualitative study aims at identifying the disciplinary strategies claimed to be used by a group of five secondary classroom teachers of English in public or semi-public schools in Chile. To conduct this research, a semi-structured interview was applied to participants. The data were analyzed using the principles of semantic content analysis…

  3. El juego entre el nacimiento y los 7 anos: Un manual para ludotecarias. Investigacion-accion sobre la Familia y la Primera Infancia. UNESCO Sector de Educacion Monografia (Play between Birth and 7 Years: A Manual for Preschool Teachers. Action Research in Family and Early Childhood. UNESCO Education Sector Monograph).

    ERIC Educational Resources Information Center

    Grellet, Carolina

    The purpose of this Spanish-language manual is to help preschool teachers better understand theoretical concepts related to children's play. Following a preface that discusses UNESCO's activities related to early childhood education, the two main sections of the manual discuss children's play between 0-2 years and 2-7 years. Each section includes…

  4. [The EMECAM protocol: an analysis of the short-term effect of air pollution on mortality. Estudio Multicéntrico Español sobre la Relación entre la Contaminación Atmosférica u la Mortalidad].

    PubMed

    Pérez-Hoyos, S; Sáez Zafra, M; Barceló, M A; Cambra, C; Figueiras Guzmán, A; Ordóñez, J M; Guillén Grima, F; Ocaña, R; Bellido, J; Cirera Suárez, L; López, A A; Rodríguez, V; Alcalá Nalvaiz, T; Ballester Díez, F

    1999-01-01

    The aim of this study is to Mortality show the protocol of analysis which was set out as part of the EMECAM Project, illustrating the application thereof to the effect of pollution has on the mortality in the city of Valencia. The response variables considered will be the daily deaths rate resulting from all causes, except external ones. The explicative variables are the daily series of different pollutants (black smoke, SO2, NO2, CO, O3). As possible confusion variables, weather factors, structural factors and weekly cases of flu are taken into account. A Poisson regression model is built up for each one of the four deaths series in two stages. In the first stage, a baseline model is fitted using the possible confusion variables. In the second stage, the pollution variables or the time legs thereof are included, controlling the residual autocorrelation by including mortality time lags. The process of fitting the baseline model is as follows: 1) Include the significant sinusoidal terms up to the sixth order. 2) Include the significant temperature or temperature squared terms with the time lags thereof up to the 7th order. 3) Repeat this process with the relative humidity. 4) Add in the significant terms of calendar years, daily tendency and tendency squared. 5) The days of the week as dummy variables are always included in the model. 6) Include the holidays and the significant time lags of up to two weeks of flu. Following the reassessment of the model, each one of the pollutants and the time lags thereof up to the fifth order are proven out. The impact is analyzed by six-month periods, including interaction terms. PMID:10410600

  5. Human Relations Activities for the Single Parent To Develop More Effective Parent/Child Relations. Bilingual Guide = Actividades sobre relaciones humanas para ayudar al padre-soltero o madre-soltera a desarrollar una relacion efectiva entre padre e hijo Guia bilingue.

    ERIC Educational Resources Information Center

    Peterson, Susan

    Written in English and Spanish, this bilingual guide offers 10 activities which single parents can use to improve their relationships with their children. Objectives of activities include: (1) developing children's responsibility for work tasks in the home; (2) improving sibling relationships; (3) discussing emergencies with children; (4)…

  6. Viviremos! On the Road to Healthy Living: A Bilingual Curriculum on AIDS and HIV Prevention for Migrant Students (Grades 6-12) = El Camino Hacia la Salud: Un Programa de Estudio Bilingue sobre la Prevencion del SIDA y del VIH para Estudiantes Migrantes (Grados 6-12).

    ERIC Educational Resources Information Center

    VAMOS (Villarreal Analytical Management and Organizational Services), San Marcos, TX.

    This curriculum provides the basic information everyone needs to avoid HIV infection, but was specifically designed for Latino farmworker students in grades 6-7. The student materials are written in Spanish and English and may be used with older student or young adults, or in English-as-a-second-language courses. An introduction provides…

  7. Mirando al Futuro del Desarrollo Humano en America Latina y el Caribe. Seminario Regional sobre Universalization de la Educacion (Sucre, Bolivia, 4-10 mayo 1987) (Looking at the Future of Human Development in Latin America and the Caribbean. Regional Seminar on the Universalization of Education [Sucre, Bolivia, May 4-10, 1987]).

    ERIC Educational Resources Information Center

    United Nations Children's Fund, Santiago (Chile). Oficina Regional para les Americas.

    One of every two children in developing nations does not complete primary school and four out of ten adults do not read or write. Of these ten, six are women. There were 44 million illiterate adults in Latin America in 1985, and of the 66 million school age children, 8.5 million were not in school. Thirty million of these children lived in…

  8. Consulta regional sobre investigacion en educacion y toma de decisiones en America Latina: Informe final (Lima, Peru, 11-15 de mayo de 1987) (Regional Meeting on Research in Education and Decision Making in Latin America: Final Report [Lima, Peru, May 11-15, 1987]).

    ERIC Educational Resources Information Center

    United Nations Educational, Scientific, and Cultural Organization, Santiago (Chile). Regional Office for Education in Latin America and the Caribbean.

    This report presents the highlights of a United Nations Educational, Scientific, and Cultural Organization (UNESCO) conference that was convened to give impetus to and encourage research programs, to analyze research policy formation, and to establish research priorities in the field of educational planning and administration. The document…

  9. Lo que los Padres Necesitan Saber sobre...Reconocer y Animar los Intereses, las Capacidades, y los Talentos de los Ninos Dotados de la Escuela Primaria. Guia Practica B0213 (What Parents Need To Know about...Recognizing and Encouraging Interests, Strengths, and Talents of Gifted Elementary School Children. Practitioners' Guide B0213).

    ERIC Educational Resources Information Center

    Delcourt, Marcia A. B.

    This brochure, written in Spanish, discusses strategies that Spanish-speaking parents can use to support the interests of their children and how to recognize and extend their children's talents. Parents are urged to: (1) be aware of what their child likes to do and be patient with the changing patterns as the child explores areas of interests and…

  10. Lo Que los Padres Necesitan Saber sobre...Reconocer y Animar los Intereses, las Capacidades, y los Talentos de los Ninos Dotados Jovenes. Guia Practica B0212 (What Parents Need To Know about...Recognizing and Encouraging Interests, Strengths, and Talents of Young Gifted Children. Practitioners' Guide B0212).

    ERIC Educational Resources Information Center

    Delcourt, Marcia A. B.

    This pamphlet, written in Spanish, is designed to help Spanish-speaking parents recognize and encourage their gifted preschool children. It begins by discussing some of the interests of very young children and lists strategies for facilitating and supporting those interests, including: provide the child with opportunities to find out about a…

  11. Lo Que los Padres Necesitan Saber sobre...Reconocer y Animar los Intereses, las Capacidades, y los Talentos de los Adolescentes. Guia Practica B0214 (What Parents Need To Know about...Recognizing Interests, Strengths, and Talents of Gifted Adolescents. Practitioners' Guide B0214).

    ERIC Educational Resources Information Center

    Delcourt, Marcia A. B.

    This brochure, written in Spanish, for Spanish-speaking parents of gifted adolescents discusses strategies to use to support the interests of their children and how to recognize and extend their children's talents. Parents are urged to: (1) increase their knowledge about the child's areas of interest; (2) discuss the child's present and future…

  12. ...And That's How It All Began: Putting Information about Your Child's Growth, Health and Safety All within Your Reach...Because the First Years Last Forever! = ...Y asi es como empezo todo: Ponemos a su alcance en forma conjunta la informacion sobre el crecimiento, la salud y la seguridad de su hijo...Porque los primeros anos duran para siempre!

    ERIC Educational Resources Information Center

    North Carolina Partnership for Children, Raleigh.

    Smart Start is North Carolina's model early childhood initiative to help all North Carolina children enter school healthy and prepared for success. This resource guide, in Spanish and English versions, is designed to provide parents with information on infant and child development, health care, and resources for further assistance. Presented in an…

  13. Consejos para los Padres Sobre la Lectura: Informacion e Ideas para Ayudar a los Ninos Desde la Infancia Hasta Octavo Grado a Tener Exito en la Lectura (Tips for Parents about Reading: Information and Ideas for Helping Children through Grade Eight Succeed with Reading).

    ERIC Educational Resources Information Center

    Davis, Deborah; Lewis, Jan Patricia

    Noting that all parents want the best school experience for their children, this booklet, in Spanish, gives parents some ideas about what to expect at different ages and stages of reading development, suggestions for what parents can do at home, and a list of favorite books parents can find in most libraries for parents and children to read.…

  14. The Role of English Pre-Service Teachers' Beliefs about Teaching in Teacher Education Programs (El papel de las creencias de los profesores de inglés en formación sobre la enseñanza en los programas de formación docente)

    ERIC Educational Resources Information Center

    Castellanos Jaimes, Judith

    2013-01-01

    This paper presents a review of studies on pre-service teachers' beliefs about teaching. The purpose of the article is to show teacher educators the relevance of exploring such issue in the classroom. Preservice teachers come into the teaching profession with beliefs about teaching; sometimes they are aware of them, other times they are not. The…

  15. Tabla de Especificaciones e Instructivo sobre Elaboracion de Pruebas Objetivas en la Ensenanza Primaria, para las asignaturas de Estudios Sociales, Idioma Espanol, Matematicas y Ciencias Naturales (Specification Tables and Instructions for the Construction of Objective Tests in the Primary Grades in Social Studies, Spanish, Mathematics, and Natural Sciences).

    ERIC Educational Resources Information Center

    Ministerio de Educacion, Guatemala City (Guatemala). Direccion de Bienestar Estudiantil y Educacion Especial.

    This booklet presents specification tables illustrating the relative importance given to topics on tests within a particular subject area. The general subject areas are social studies, Spanish, mathematics, and natural sciences. Tables are provided for final exams in each of these areas for several primary grades, illustrating the importance of…

  16. How To Talk to Your Doctor (and Get Your Doctor To Talk to You!). An Educational Workshop on Doctor Patient Communication = Como Hablarle a su Doctor (iY que su doctor le hable a usted!). Un seminario educativo sobre la comunicacion entre el doctor y el paciente.

    ERIC Educational Resources Information Center

    Baylor Coll. of Medicine, Houston, TX.

    This workshop, written in both English and Spanish, focuses on improving communication between physician and patient. In the workshop, the trainers will talk about "building bridges" between patient and doctor by understanding the doctor's role and his/her duty to the patient. According to the workshop, a person's doctor should communicate…

  17. Novice Non-Native English Teachers' Reflections on Their Teacher Education Programmes and Their First Years of Teaching (Reflexiones de profesores novatos y no nativos del inglés sobre sus programas de formación y sus primeros años de instrucción)

    ERIC Educational Resources Information Center

    Akcan, Sumru

    2016-01-01

    This study investigates novice non-native English teachers' opinions about the effectiveness of their teacher education programme and the challenges during their initial years of teaching. The results of a survey administered to fifty-five novice teachers and follow-up interviews identify strengths and weaknesses in their teacher education…

  18. Vínculos sobre um modelo de quartessência de Chaplygin usando observações do satélite chandra da fração de massa de gás em aglomerados de galáxias

    NASA Astrophysics Data System (ADS)

    de Souza, R. S.

    2003-08-01

    Observações de Supernovas do tipo Ia mostram que a expansão do Universo está acelerando. Segundo as equações de Einstein uma componente com pressão negativa (energia escura) é necessária para explicar a aceleração cósmica. Além da energia escura é usualmente admitido que no Universo há também uma matéria exótica com pressão zero, que é chamada de matéria escura. Essa componente possui um papel fundamental na formação de estruturas no Universo. Recentemente tem se explorado a possibilidade de que matéria e energia escura poderiam ser unificadas através de uma única componente, que tem sido denominada de quartessência. Um exemplo de fluido com essas características é o Gás de Chaplygin Generalizado, que possui uma equação de estado da forma p = -A/ra. Inicialmente consideramos o caso especial a = 1 (gás de Chaplygin) e vinculamos parâmetros do modelo utilizando observações em raios-X do satélite Chandra da fração de massa de gás em aglomerados de galáxias. Uma comparação dos vínculos obtidos com esse teste com outros testes, tais como supernovas e idade do Universo, mostra que esse teste é bastante restritivo. Exibiremos ainda resultados para o caso em que a curvatura é nula e o parâmetro a está compreendido no intervalo -1 < a 1.

  19. Students and Teachers' Reasons for Using the First Language within the Foreign Language Classroom (French and English) in Central Mexico (Razones de alumnos y maestros sobre el uso de la primera lengua en el salón de lenguas extranjeras (francés e inglés) en el centro de México)

    ERIC Educational Resources Information Center

    Mora Pablo, Irasema; Lengeling, M. Martha; Rubio Zenil, Buenaventura; Crawford, Troy; Goodwin, Douglas

    2011-01-01

    The present study explores the use of the first language in a context of foreign language teaching. This qualitative research presents the classroom practice and points of view of French and English teachers and students within a public educational institute in central Mexico using the techniques of questionnaires and semi-structured interviews.…

  20. Lo que Piensan los Estudiantes y Profesores Sobre la Calidad de la Educacion Superior. Estudio Comparativo en 5 Instituciones de Educacion Superior--dos publicas y tres privadas--en Guadalajara, Jalisco, Mexico (What Students and Faculties Think about the Quality of Higher Education. Comparative Study of 5 Higher Education Institutions--Two Public and Three Private--in Guadalajara, Jalisco, Mexico).

    ERIC Educational Resources Information Center

    Yanez, Maria Lorena Hernandez

    This study, written in Spanish, compared attitudes of students (N=302) and faculty (N=28) at five institutions of higher education (two public and three private) in Guadalajara, Jalisco, Mexico. The study explored first, whether respondents believed there are significant quality differences between private and public universities and, second, what…

  1. Exploring EFL Pre-Service Teachers' Experience with Cultural Content and Intercultural Communicative Competence at Three Colombian Universities (Indagación sobre la experiencia con el contenido cultural y la competencia comunicativa intercultural de docentes de inglés en formación, en tres universidades colombianas)

    ERIC Educational Resources Information Center

    Olaya, Alba; Gómez Rodríguez, Luis Fernando

    2013-01-01

    This article reports the findings of a qualitative research project that explored pre-service English teachers' perceptions of and attitudes toward the aspects of culture and intercultural competence addressed in their English classes in the undergraduate programs at three Colombian universities. Findings reveal that pre-service teachers are…

  2. Algunas Premisas Metodologicas y Conceptuales sobre el Desarrollo de los Movimientos en el Primer Ano de Vida (0-12 Meses) (Some Methodological and Conceptual Premises about the Development of Movement in the First Year of Life (0-12 Months)).

    ERIC Educational Resources Information Center

    Bequer Diaz, Gladys

    1997-01-01

    Examined the emergence of principal and secondary movements in Cuban children in their first year of life. Based on 35 examples of observed movements, an integrated program of activity is developed to assist in the development of physical skills which are essential to the development of a well-rounded personality. (AS)

  3. Attending School and Learning or Repeating and Leaving. A Study about the Determinants of Grade Repetition and Dropout in Primary School in Honduras. Synthesis of the Study = Asistir y Aprender o Repetir y Desertar. Un Estudio sobre los Factores que Contribuyen a la Repitencia en la Escuela Primaria en Honduras. Sintesis del Informe.

    ERIC Educational Resources Information Center

    McGinn, Noel F.; And Others

    This paper synthesizes a study designed to identify the factors that contribute to primary school repetition and dropout in Honduras. Data were collected by record reviews; teacher, student, and parent interviews; and a test of Spanish. The sample included 1,253 students in grades 1 and 3 in 40 schools in rural Honduras. The main findings of the…

  4. Manual for ERLE (Energy-Related Laboratory Equipment). Instructions and information for institutions of higher learning concerning used energy-related laboratory equipment grants; Manual para ERLE [Equipo de Laboratorio Relacionado con la Energia]. Instrucciones e informacion para instituciones de educacion superior sobre subvenciones de equipo de laboratorio usado relacionado con la energia

    SciTech Connect

    Not Available

    1994-10-01

    This is a listing of energy related equipment available through the Energy-Related Laboratory Equipment Grant Program which grants used equipment to institutions of higher education for energy-related research. Information included is an overview of the program, how to apply for a grant of equipment, eligibility requirements, types of equipment available, and the costs for the institution.

  5. Educacion, Salud y Bienestar para el Nino Preescolar y la Familia. (5 de Enero--28 de Febrero, 1997) Informe Curso sobre (Education, Health, and Well-Being of Preschool Children and the Family. January 5 - February 28, 1997. Report of a Course).

    ERIC Educational Resources Information Center

    Golda Meir Mount Carmel International Training Centre, Haifa (Israel).

    This report describes a course held in Spanish at the Golda Meir Mount Carmel International Training Center in Haifa, Israel. The course considered various themes related to the education, health, and well-being of preschool children. Participants were 30 individuals from Central and South American countries who held decision-making positions in…

  6. Una guia para los padres sobre lo mas importante: el logro academico plan de educacion de Maryland desde preescolar hasta el 12 grado, 2002-2003. (A Parent's Guide to Achievement Matters Most: Maryland's Plan for PreK-12 Education, 2002-2003).

    ERIC Educational Resources Information Center

    Maryland State Dept. of Education, Baltimore.

    To raise the achievement of every student in the state, Maryland implemented "Achievement Matters Most," a new plan for public elementary and secondary schools that sets goals in the areas of achievement, teaching, testing, safety, and family involvement in schools. This Spanish-language guide for parents outlines the goals and characteristics of…

  7. Efectos Especiales de Anclaje (Estudio sobre Regresiones de Juicios Condicionales). Parte 2: Invariancia del Juicio No-Condicional Como Valor Estandar Para el Juicio Condicional (Special Effects of Anchoring (Study of Regression of Conditional Judgements) Part 2: Invariance of Unconditional Judgments as Standard Value for the Conditional Judgment). Publication No. 31.

    ERIC Educational Resources Information Center

    Lopez Alonso, A. O.

    From the best-fit lines corresponding to sets of families of conditional judgements, the constant stimulus family and the constant condition family, both defined for a same scale object, the coordinate values of the point of intersection of both lines (indifference point) are obtained. These values are studied in relation to the mean values of the…

  8. Los Hispanos: Problemas y Oportunidades. Resumen de la Actual Situacion Demografica, Economica, Social y Politica de los Hispanos en los Estados Unidos y de las Iniciativas Tomadas por la Fundacion Ford Para Hacer Frente a las Necesidades de esta Poblacion en Aumento y Determinar sus Efectos Sobre la Sociedad Estadounidense. Documento de Trabajo de la Fundacion Ford, No. 436.

    ERIC Educational Resources Information Center

    Ford Foundation, New York, NY.

    The Hispanic population's growing impact on American society has caused the Ford Foundation to explore new Foundation initiatives. The 1980 census revealed 14.6 million Hispanics: 60% Mexican American; 14% Puerto Rican; 6% Cuban, and 20% Other. The Hispanic population in the United States is growing and is characterized by diversity; rapid growth…

  9. Exploring Conceptions about Writing and Learning: Undergraduates' Patterns of Beliefs and the Quality of Academic Writing (Acercamiento a las concepciones sobre la escritura y el aprendizaje: patrones de creencias de los universitarios y la calidad de su redacción académica)

    ERIC Educational Resources Information Center

    Martínez-Fernández, J. R.; Corcelles, M.; Bañales, G.; Castelló, M.; Gutiérrez-Braojos, C.

    2016-01-01

    Introduction: In this study, the conceptions of learning and writing of a group of undergraduates enrolled in a teacher education programme were identified. The relationship between them were analysed, and a set of patterns of beliefs about learning and writing were defined. Finally, the relation between these patterns and the quality of a text…

  10. MO-G-BRF-09: Investigating Magnetic Field Dose Effects in Mice: A Monte Carlo Study

    SciTech Connect

    Rubinstein, A; Guindani, M; Followill, D; Melancon, A; Hazle, J; Court, L

    2014-06-15

    Purpose: In MRI-linac treatments, radiation dose distributions are affected by magnetic fields, especially at high-density/low-density interfaces. Radiobiological consequences of magnetic field dose effects are presently unknown; therefore, preclinical studies are needed to ensure the safe clinical use of MRI-linacs. This study investigates the optimal combination of beam energy and magnetic field strength needed for preclinical murine studies. Methods: The Monte Carlo code MCNP6 was used to simulate the effects of a magnetic field when irradiating a mouse-sized lung phantom with a 1.0cmx1.0cm photon beam. Magnetic field effects were examined using various beam energies (225kVp, 662keV[Cs-137], and 1.25MeV[Co-60]) and magnetic field strengths (0.75T, 1.5T, and 3T). The resulting dose distributions were compared to Monte Carlo results for humans with various field sizes and patient geometries using a 6MV/1.5T MRI-linac. Results: In human simulations, the addition of a 1.5T magnetic field caused an average dose increase of 49% (range:36%–60%) to lung at the soft tissue-to-lung interface and an average dose decrease of 30% (range:25%–36%) at the lung-to-soft tissue interface. In mouse simulations, the magnetic fields had no effect on the 225kVp dose distribution. The dose increases for the Cs-137 beam were 12%, 33%, and 49% for 0.75T, 1.5T, and 3.0T magnetic fields, respectively while the dose decreases were 7%, 23%, and 33%. For the Co-60 beam, the dose increases were 14%, 45%, and 41%, and the dose decreases were 18%, 35%, and 35%. Conclusion: The magnetic field dose effects observed in mouse phantoms using a Co-60 beam with 1.5T or 3T fields and a Cs-137 beam with a 3T field compare well with those seen in simulated human treatments with an MRI-linac. These irradiator/magnet combinations are suitable for preclinical studies investigating potential biological effects of delivering radiation therapy in the presence of a magnetic field. Partially funded by Elekta.

  11. Lung Cancer Cell Line Screen Links Fanconi Anemia/BRCA Pathway Defects to Increased Relative Biological Effectiveness of Proton Radiation

    SciTech Connect

    Liu, Qi; Ghosh, Priyanjali; Magpayo, Nicole; Testa, Mauro; Tang, Shikui; Gheorghiu, Liliana; Biggs, Peter; Paganetti, Harald; Efstathiou, Jason A.; Lu, Hsiao-Ming; Held, Kathryn D.; Willers, Henning

    2015-04-01

    Purpose: Growing knowledge of genomic heterogeneity in cancer, especially when it results in altered DNA damage responses, requires re-examination of the generic relative biological effectiveness (RBE) of 1.1 of protons. Methods and Materials: For determination of cellular radiosensitivity, we irradiated 17 lung cancer cell lines at the mid-spread-out Bragg peak of a clinical proton beam (linear energy transfer, 2.5 keV/μm). For comparison, 250-kVp X rays and {sup 137}Cs γ-rays were used. To estimate the RBE of protons relative to {sup 60}Co (Co60eq), we assigned an RBE(Co60Eq) of 1.1 to X rays to correct the physical dose measured. Standard DNA repair foci assays were used to monitor damage responses. FANCD2 was depleted using RNA interference. Results: Five lung cancer cell lines (29.4%) exhibited reduced clonogenic survival after proton irradiation compared with X-irradiation with the same physical doses. This was confirmed in a 3-dimensional sphere assay. Corresponding proton RBE(Co60Eq) estimates were statistically significantly different from 1.1 (P≤.05): 1.31 to 1.77 (for a survival fraction of 0.5). In 3 of these lines, increased RBE was correlated with alterations in the Fanconi anemia (FA)/BRCA pathway of DNA repair. In Calu-6 cells, the data pointed toward an FA pathway defect, leading to a previously unreported persistence of proton-induced RAD51 foci. The FA/BRCA-defective cells displayed a 25% increase in the size of subnuclear 53BP1 foci 18 hours after proton irradiation. Conclusions: Our cell line screen has revealed variations in proton RBE that are partly due to FA/BRCA pathway defects, suggesting that the use of a generic RBE for cancers should be revisited. We propose that functional biomarkers, such as size of residual 53BP1 foci, may be used to identify cancers with increased sensitivity to proton radiation.

  12. CHARACTERIZATION OF GRAPHITE SLEEVES FROM BUGEY 1 EDF PLANT FOR PERMANENT DISPOSAL--MEASUREMENT AND CALCULATION OF SCALING FACTORS FOR DIFFICULT-TO-MEASURE NUCLIDES

    SciTech Connect

    PONCET, Bernard R.

    2003-02-27

    Electricite De France's Bugey-1 reactor, with graphite moderator, was shutdown permanently in 1994. The natural uranium elements are encased in graphite sleeves to facilitate handling. 2,000 m3 of concrete containers, containing non conditioned graphite sleeves, must be characterized and conditioned before shipment to the national repository site called ''Centre de l'Aube''. The characterization work consists in quantifying Difficult-To-Measure nuclides (DTM) by the use of Scaling Factors (SF), which use Co-60 as tracer. Bugey developed an industrial method for the gamma counting of each package to perform easily and rapidly the measurement of the Co-60 content. Depending upon the DTM radionuclide, Co-60 scaling factors are determined, or by measurement on graphite samples (case of C-14, Cl-36, Ni-63, H-3), either by using a calculation technique which is based upon the impurities present in the graphite sleeves. This method is applied for the other pure beta emitters all DTM radionucli des : Ag-108m, Be-10, Ca-41, Cd-109, Cd-113m, Co-57, Cs-135, Cs-137, Eu-155, Fe-55, Gd-153, Mo-93, Nb- 93m, Nb-94, Ni-59, Pd-107, Pm-147, Sm-151, Sn-119m, Sn-121m, Sn-126, Sr-90, Tc-99, V-49 and Zr-93. Calculations use six sleeve history cases : 1 year at 50% power, 2 years at 50 % power, 3 years at 50 % power, 4 years at 50 % power, 1 year at 100 % power and 2 years at 100 % power. The DTM nuclides have been calculated from impurity concentrations for each of these six cases, and the greatest scaling factor has been kept. The calculation is based upon two impurity sets: First impurity set : a reverse activation calculation provides us with the best estimate value of impurities calculated from the measured mean gamma spectrum and from measured scaling factors. It consists in solving a system of simultaneous equations for the impurities as a function of the mean gamma radioactive spectrum and of the measured scaling factors. The concerned calculated impurities are Co, Cl, Li, Ag, Cs

  13. Joint Assessment of ETRR-2 Research Reactor Operations Program, Capabilities, and Facilities

    SciTech Connect

    Bissani, M; O'Kelly, D S

    2006-05-08

    operated infrequently for radioisotope production. Because the two irradiation programs compete by utilizing the same core locations, the issues should be resolved at a high level. (c) Cobalt-60 production uses the most valuable irradiation location in the ETRR-2 (the high neutron density flux-trap), but there seems to be no potential customer for the Co-60. Further, the low number of hours the reactor is operated per week precludes ever producing a marketable specific activity of Co-60. Accordingly, Co-60 production should be reevaluated. (d) ETRR-2 staff would benefit from additional training to successfully design new experiment facilities and utilize existing facilities more effectively. This training can include IAEA Fellowships, as well as topical DOE Sister Laboratory visits to gain experience using equipment and research tools at other research reactor facilities.

  14. Instantánea del cáncer de riñón

    Cancer.gov

    Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer de riñón; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

  15. Prevención del cáncer de ovario (PDQ®)—Versión para pacientes

    Cancer.gov

    Sumario de información revisada por expertos sobre factores que pueden influir en el riesgo de presentar cáncer de ovario, de trompas de Falopio y primario de peritoneo y sobre las investigaciones dirigidas a prevenir los mismos.

  16. Instantánea del melanoma

    Cancer.gov

    Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el melanoma; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

  17. 76 FR 34296 - Proposed Collection; Comment Request for Forms 1040-PR and 1040-SS

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-13

    ... para la Declaraci n de la Contribuci n Federal sobre el Trabajo por Cuenta Propia (Incluyendo el Cr... para la Declaraci n de la Contribuci n Federal sobre el Trabajo por Cuenta Propia (Incluyendo el Cr... collection techniques or other forms of information technology; and (e) estimates of capital or...

  18. 77 FR 72268 - Rules Relating to Additional Medicare Tax

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-05

    ... associated with the proposed collection of information; and Estimates of capital or start-up costs and costs... Declaraci n de la Contribuci n Federal sobre el Trabajo por Cuenta Propia (Incluyendo el Cr dito Tributario... Declaraci n de la Contribuci n Federal sobre el Trabajo por Cuenta Propia (Incluyendo el Cr dito...

  19. Calcio y la prevención del cáncer

    Cancer.gov

    Hoja informativa que resume los resultados de estudios sobre el calcio y la prevención del cáncer. Incluye información sobre las recomendaciones dietéticas para calcio y la cantidad de calcio en los alimentos y en complementos de calcio.

  20. Terapia hormonal para la menopausia y el cáncer

    Cancer.gov

    Hoja informativa acerca de los resultados de los estudios sobre el uso de la terapia hormonal para la menopausia. Incluye información sobre el efecto de esta terapia en el cuerpo y explica los riesgos y beneficios del uso de hormonas.

  1. Instantánea del cáncer de seno (mama)

    Cancer.gov

    Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer de seno (mama); así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

  2. Instantánea de los cánceres de hígado

    Cancer.gov

    Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre los cánceres de hígado y de las vías biliares; así como ejemplos de actividades del NCI y adelantos en la investigación de estos tipos de cáncer.

  3. Prevención del cáncer de estómago (gástrico) (PDQ®)—Versión para pacientes

    Cancer.gov

    Sumario de información revisada por expertos sobre factores que pueden influir en el riesgo de presentar cáncer de estómago y sobre las investigaciones dirigidas a la prevención de esta enfermedad.

  4. Instantánea del cáncer de tiroides

    Cancer.gov

    Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer de tiroides; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

  5. Instantánea del cáncer de vejiga

    Cancer.gov

    Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer de vejiga; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

  6. Neuropatía periférica inducida por quimioterapia

    Cancer.gov

    Artículo sobre un efecto secundario de la quimioterapia que causa dolor y malestar en las manos y los pies. También incluye información sobre los esfuerzos para mejorar las opciones de detección, tratamiento y prevención.

  7. Instantánea del sarcoma de Kaposi

    Cancer.gov

    Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el sarcoma de Kaposi; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

  8. Instantánea del linfoma

    Cancer.gov

    Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el linfoma; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

  9. Prevención del cáncer de ovario, trompas y peritoneo (PDQ®)—Versión para profesionales de salud

    Cancer.gov

    Sumario de información revisada por expertos sobre factores que influirían en el riesgo de presentar cáncer de ovario, de trompas de Falopio y primario de peritoneo y sobre las investigaciones dirigidas a la prevención de los mismos.

  10. Hacer frente - Obtener cuidados médicos de seguimiento

    Cancer.gov

    Información sobre los cuidados médicos de seguimiento después del tratamiento del cáncer. Trata sobre su plan de cuidados de seguimiento, cómo obtener un plan para el bienestar e incluye una guía para una vida saludable.

  11. Instantánea del mieloma

    Cancer.gov

    Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el mieloma; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

  12. Instantánea del cáncer de pulmón

    Cancer.gov

    Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer de pulmón; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

  13. Control del dolor: Apoyo para las personas con cáncer

    Cancer.gov

    Contiene información sobre las medicinas contra el dolor para pacientes con cáncer, los planes para controlarlo, cómo hablar con su equipo de atención médica sobre el dolor que usted siente y qué hacer para controlar los efectos físicos y emocionales del

  14. Instantánea del cáncer de páncreas

    Cancer.gov

    Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer de páncreas; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

  15. Instantánea de los cánceres de cabeza y cuello

    Cancer.gov

    Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre los cánceres de cabeza y cuello; así como ejemplos de actividades del NCI y adelantos en la investigación de estos tipos de cáncer.

  16. Instantánea del cáncer de cuello uterino

    Cancer.gov

    Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer de cuello uterino; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

  17. Prevención del cáncer de cavidad oral y orofaringe (PDQ®)—Versión para profesionales de salud

    Cancer.gov

    Sumario de información revisada por expertos sobre factores que pueden influir en el riesgo de presentar cáncer de labio, cavidad oral y orofaringe, y sobre las investigaciones dirigidas a la prevención de esta enfermedad.

  18. Instantánea de los cánceres de cerebro y del sistema nervioso central

    Cancer.gov

    Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre los cánceres de cerebro y del sistema nervioso central; así como ejemplos de actividades del NCI y adelantos en la investigación de estos tipos de cáncer.

  19. Prevención del cáncer de estómago (gástrico) (PDQ®)—Versión para profesionales de salud

    Cancer.gov

    Sumario de información revisada por expertos sobre factores que pueden influir en el riesgo de presentar cáncer de estómago y sobre las investigaciones dirigidas a la prevención de esta enfermedad.

  20. Instantánea del cáncer de esófago

    Cancer.gov

    Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer de esófago; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

  1. Instantánea del cáncer colorrectal

    Cancer.gov

    Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer colorrectal; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

  2. Instantánea del cáncer de estómago

    Cancer.gov

    Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer de estómago; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

  3. Capacitación del personal y de los pacientes en torno a los cuidados terminales

    Cancer.gov

    Artículo sobre programas innovadores de base científica para ayudar a médicos y pacientes a hablar sobre la transición de un tratamiento activo para el cáncer a los cuidados en la etapa final de la vida.

  4. Instantánea del cáncer de ovario

    Cancer.gov

    Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer de ovario; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

  5. Instantánea del cáncer de endometrio

    Cancer.gov

    Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer de endometrio; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

  6. Instantánea del cáncer de próstata

    Cancer.gov

    Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer de próstata; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

  7. Instantánea del sarcoma

    Cancer.gov

    Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el sarcoma; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

  8. Instantánea de la leucemia

    Cancer.gov

    Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre la leucemia; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

  9. Verification of EPA's ''Preliminary Remediation Goals for radionuclides'' (PRG) electronic calculator

    SciTech Connect

    Jannik, Tim; Stagich, Brooke

    2015-08-28

    The U.S. Environmental Protection Agency (EPA) requested an external, independent verification study of their updated “Preliminary Remediation Goals for Radionuclides” (PRG) electronic calculator. The calculator provides PRGs for radionuclides that are used as a screening tool at Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and Resource Conservation and Recovery Act (RCRA) sites. These risk-based PRGs establish concentration limits under specific exposure scenarios. The purpose of this verification study is to determine that the calculator has no inherit numerical problems with obtaining solutions as well as to ensure that the equations are programmed correctly. There are 167 equations used in the calculator. To verify the calculator, all equations for each of seven receptor types (resident, construction worker, outdoor and indoor worker, recreator, farmer, and composite worker) were hand calculated using the default parameters. The same four radionuclides (Am-241, Co-60, H-3, and Pu-238) were used for each calculation for consistency throughout.

  10. Evaluation Of Shielding Efficacy Of A Ferrite Containing Ceramic Material

    SciTech Connect

    Verst, C.

    2015-10-12

    The shielding evaluation of the ferrite based Mitsuishi ceramic material has produced for several radiation sources and possible shielding sizes comparative dose attenuation measurements and simulated projections. High resolution gamma spectroscopy provided uncollided and scattered photon spectra at three energies, confirming theoretical estimates of the ceramic’s mass attenuation coefficient, μ/ρ. High level irradiation experiments were performed using Co-60, Cs-137, and Cf-252 sources to measure penetrating dose rates through steel, lead, concrete, and the provided ceramic slabs. The results were used to validate the radiation transport code MCNP6 which was then used to generate dose rate attenuation curves as a function of shielding material, thickness, and mass for photons and neutrons ranging in energy from 200 keV to 2 MeV.

  11. Towards a Measurement of the Half-Life of {sup 60}Fe for Stellar and Early Solar System Models

    SciTech Connect

    Ostdiek, K.; Anderson, T.; Bauder, W.; Bowers, M.; Collon, P.; Dressler, R.; Greene, J.; Kutschera, W.; Lu, W.; Paul, M.

    2015-10-15

    Radioisotopes, produced in stars and ejected into the Interstellar Medium, are important for constraining stellar and early Solar System (ESS) models. In particular, the half-life of the radioisotope, Fe-60, can have an impact on calculations for the timing for ESS events, the distance to nearby Supernovae, and the brightness of individual, non-steady-state Fe gamma ray sources in the Galaxy. A half-life measurement has been undertaken at the University of Notre Dame and measurements of the Fe-60/Fe-56 concentration of our samples using Accelerator Mass Spectrometry has begun. This result will be coupled with an activity measurement of the isomeric decay in Co-60, which is the decay product of Fe. Preliminary half-life estimates of (2.53 +/- 0.24) x 10(6) years seem to confirm the recent measurement by Rugel et al. (2009). (C) 2015 Elsevier B.V. All rights reserved.

  12. Experimental investigation of the multiple scatter peak of gamma rays in portland cement in the energy range 279-1332 keV

    NASA Astrophysics Data System (ADS)

    Singh, Tejbir; Singh, Parjit S.

    2011-12-01

    The pulse height spectra for different thicknesses of portland cement in the reflected geometry has been recorded with the help of a NaI(Tl) scintillator detector and 2 K MCA card using different gamma-ray sources such as Hg203 (279 keV), Cs137 (662 keV) and Co60 (1173 and 1332 keV). It has been observed that the multiple scatter peak for portland cement appears at 110 (±7) keV in all the spectra irrespective of different incident photon energies in the range 279-1332 keV from different gamma-ray sources. Further, the variation in the intensity of the multiple scatter peak with the thickness of portland cement in the backward semi-cylinders has been investigated.

  13. Pre-irradiation-induced graft reaction of maleic anhydride onto polypropylene

    NASA Astrophysics Data System (ADS)

    Tan, X. M.; Xu, Y. S.; Wang, C. L.

    2006-09-01

    The radiation induced graft polymerization is a well-known method to obtain new materials. Until recently, only conventional radiation sources, such as Co-60 and electron beams, were used. Moreover, part of the damage induced in polymers by heavy ions can produce active sites (peroxides and hydroperoxides) that are useful to initiate grafting reactions. Maleic anhydride (MAH) was grafted onto polypropylene (PP) wax with a number-average molecular weight (Mn) of 8000 by gamma pre-irradiation technique. Effects of total dose, monomer concentration, reaction time, and temperature on percentage of grafting are studied in detail. It is shown that the optimum conditions for grafting are temperature of 70 degrees C and total dose of 14.4 kGy. PP-g-MAH is characterized by infrared spectrum. Differential scanning calorimetry shows that the compatibility of PP-g-MAH is better than that of PP.

  14. Neoplastic cell transformation by energetic heavy ions and its modification with chemical agents

    NASA Technical Reports Server (NTRS)

    Yang, T. C.; Tobias, C. A.

    1984-01-01

    One of the major deleterious late effects of ionizing radiation is related to the induction of neoplasms. In the present report recent experimental results on neoplastic cell transformation by heavy ions are presented, and possible means to circumvent the carcinogenic effect of space radiation are discussed. Biological effects observed in experiments involving the use of energetic heavy ions accelerated at the Bevalac suggest that many of the biological effects observed in earlier space flight experiments may be due to space radiation, particularly cosmic rays. It is found that the effect of radiation on cell transformation is dose-rate dependent. The frequency of neoplastic transformation for a given dose decreases with a decrease of dose rate of Co-60 gamma rays. It is found that various chemical agents give radiation protection, including DMSO.

  15. Preparation and characterization of tungsten/epoxy composites for γ-rays radiation shielding

    NASA Astrophysics Data System (ADS)

    Chang, Le; Zhang, Yan; Liu, Yujian; Fang, Jun; Luan, Weilin; Yang, Xiangmin; Zhang, Weidong

    2015-08-01

    Tungsten/epoxy composites were prepared by blending epoxy resin with different weight percent of tungsten powder. The effect of filler loading on shielding and mechanical properties of composites was investigated by using two different activities of Co-60 source. And radiation degradation mechanism was studied according to the changes of free radicals concentrations, mechanical properties and thermal properties of composites. The results show that with the increment of tungsten loading, shielding property of composites increases. However, with the increase of irradiation dose, thermal stability and mechanical properties of composites decrease firstly, then increase slightly, and decline sharply at the end due to competition reaction between chain scission and cross-linking originated from γ-rays radiation.

  16. Thermoluminescent dosimeter measurements and analysis for LDEF experiment M0006

    NASA Technical Reports Server (NTRS)

    Stauber, Michael C.; Chang, J.; Kantorcik, T.

    1991-01-01

    Glow curve measurements are reported up to 600 C of (Thermoluminescent Dosimeter Measurement) TLD-100 (LiF) samples deployed on Long Duration Exposure Facility (LDEF) and retained as ground control. Lab exposure simulations are also reported with Co-60 radiation, low energy light ions and high energy protons in an effort to replicate the glow curves, especially the high temperature peaks observed in the LDEF TLD specimens. The evidence to date clearly shows the effect of inflight anneal on the low temperature part of the glow curve. It also shows that the high temperature part of the glow curve appears due to ion dose deposition. Initial correlations between high temperature glow peaks and effective LET of the registered dose is given.

  17. Fast neutron therapy with high intensity Cf-252 sources by remotely controlled afterloading and clinical experiences in the treatment of gynaecological cancers

    SciTech Connect

    Yamashita, H.; Hashimoto, S.; Wada, M.; Dokiya, T.

    1986-01-01

    Cf-252 fast neutron therapy with high intensity Cf-252 sources was tested for the treatment of advanced gynaecological cancers using a remotely controlled afterloading machine designed by the author and manufactured by Toshiba. Using high intensity sources and short treatment times in a special treatment room, personnel or environment exposure to radiation was at a safe level, i.e. almost nil. During 1978-1983 18 stage III cases of cancer of the uterine cervix were treated with complete response in 78% and 44% 5 year survivals. The types of acute and delayed effects of Cf-252 were the same as Co-60 or Cs-137 but the rectum was found sensitive in this system of brachytherapy. A dose of 1,000-1,500 cGy/6-10 F in 10-22 days of Cf-252 radiation was tolerated and produced tumor cure.

  18. Elemental PGNAA analysis using gamma-gamma coincidence counting with the library least-squares approach

    NASA Astrophysics Data System (ADS)

    Metwally, Walid A.; Gardner, Robin P.; Mayo, Charles W.

    2004-01-01

    An accurate method for determining elemental analysis using gamma-gamma coincidence counting is presented. To demonstrate the feasibility of this method for PGNAA, a system of three radioisotopes (Na-24, Co-60 and Cs-134) that emit coincident gamma rays was used. Two HPGe detectors were connected to a system that allowed both singles and coincidences to be collected simultaneously. A known mixture of the three radioisotopes was used and data was deliberately collected at relatively high counting rates to determine the effect of pulse pile-up distortion. The results obtained, with the library least-squares analysis, of both the normal and coincidence counting are presented and compared to the known amounts. The coincidence results are shown to give much better accuracy. It appears that in addition to the expected advantage of reduced background, the coincidence approach is considerably more resistant to pulse pile-up distortion.

  19. Effects of high energy radiation on the mechanical properties of epoxy/graphite fiber reinforced composites

    NASA Technical Reports Server (NTRS)

    Fornes, R. E.; Gilbert, R. D.; Memory, J. D.

    1987-01-01

    Publications and theses generated on composite research are listed. Surface energy changes of an epoxy based on tetraglycidyl diaminodiphenyl methane (TGDDM)/diaminodiphenyl sulfone (DDS), T-300 graphite fiber and T-300/5208 (graphite fiber/epoxy) composites were investigated after irradiation with 0.5 MeV electrons. Electron spin resonance (ESR) investigations of line shapes and the radical decay behavior were made of an epoxy based on tetraglycidyl diaminodiphenyl methane (TGDDM)/diaminodiphenyl sulfone (DDS), T-300 graphite fiber, and T-300/5208 (graphite fiber/epoxy) composites after irradiation with Co(60) gamma-radiation or 0.5 MeV electrons. The results of the experiments are discussed.

  20. Interfacial perpendicular magnetic anisotropy and damping parameter in ultra thin Co2FeAl films

    NASA Astrophysics Data System (ADS)

    Cui, Yishen; Khodadadi, Behrouz; Schäfer, Sebastian; Mewes, Tim; Lu, Jiwei; Wolf, Stuart A.

    2013-04-01

    B2-ordered Co2FeAl films were synthesized using an ion beam deposition tool. A high degree of chemical ordering ˜81.2% with a low damping parameter (α) less than 0.004 was obtained in a 50 nm thick film via rapid thermal annealing at 600 °C. The perpendicular magnetic anisotropy (PMA) was optimized in ultra thin Co2FeAl films annealed at 350 °C without an external magnetic field. The reduced thickness and annealing temperature to achieve PMA introduced extrinsic factors thus increasing α significantly. However, the observed damping of Co2FeAl films was still lower than that of Co60Fe20B20 films prepared at the same thickness and annealing temperature.

  1. Prediction and measurement of radiation damage to CMOS devices on board spacecraft

    NASA Technical Reports Server (NTRS)

    Cliff, R. A.; Danchenko, V.; Stassinopoulos, E. G.; Sing, M.; Brucker, G. J.; Ohanian, R. S.

    1976-01-01

    The CMOS Radiation Effects Measurement (CREM) experiment is presently being flown on the Explorer-55. The purpose of the experiment is to evaluate device performance in the actual space radiation environment and to correlate the respective measurements to on-the-ground laboratory irradiation results. The experiment contains an assembly of C-MOS and P-MOS devices shielded in front by flat slabs of aluminum and by a practically infinite shield in the back. Predictions of radiation damage to C-MOS devices are based on standard environment models and computational techniques. A comparison of the shifts in CMOS threshold potentials, that is, those measured in space to those obtained from the on-the-ground simulation experiment with Co-60, indicates that the measured space damage is smaller than predicted by about a factor of 2-3 for thin shields, but agrees well with predictions for thicker shields.

  2. Variation in radical decay rates in epoxy as a function of crosslink density

    NASA Technical Reports Server (NTRS)

    Kent, G. M.; Memory, J. M.; Gilbert, R. D.; Fornes, R. E.

    1983-01-01

    A study was made of the behavior of radicals generated by Co-60 gamma radiation in the epoxy system tetraglycidyl-4,4'-diaminodiphenyl methane (TGDDM) cured with 4,4'-diaminodiphenyl sulfone (DDS). The molar ratio of TGDDM to DDS was varied in the epoxy samples, and they were prepared under the same curing conditions to obtain various extents of crosslinking. ESR spectrometry data suggest that the rate of decay of radicals is related to inhomogeneities in the resin, with radicals in the highly crosslinked regions having long decay times. The inhomogeneities are thought to be due to statistical variation associated with the complex crosslinking reactions or to difficulties in mixing the reactants.

  3. A study of photon interaction in some hormones

    NASA Astrophysics Data System (ADS)

    Manjunatha, H. C.

    2013-05-01

    The effective atomic numbers (Z eff) and electron density (N el) of some hormones such as testosterone, methandienone, estradiol and rogesterone for total and partial photon interactions have been computed in the wide energy region 1 keV-100 GeV using an accurate database of photon-interaction cross sections and the WinXCom program. The computed Z eff and N el are compared with the values generated by XMuDat program. The computer tomography (CT) numbers and kerma values relative to air are also calculated and the computed data of CT numbers in the low-energy region help in visualizing the image of the biological samples and to obtain precise accuracy in treating the inhomogenity of them in medical radiology. In view of dosimetric interest, the photon absorbed dose rates of some commonly used gamma sources (Na-21, Cs-137, Mn-52, Co-60 and Na-22) are also estimated.

  4. Measurement of radiation exposure of astronauts by radiochemical techniques

    NASA Technical Reports Server (NTRS)

    Brodzinski, R. L.

    1973-01-01

    A cosmic radiation dose to the Apollo 17 crew of 1.3 R was calculated from the specific activities of Na-24 in their postflight urine specimens. The specific activities of K-42, Cr-51, Co60, and Sb-124, introduced by injection into the astronauts, are extremely high in these specimens. The Fe-59 and Cs-137 levels are also reported and appear to be normal. The concentrations of Na, K, Rb, Cs, Ca, Sr, Ba, Cr, Fe, Co, Ag, Au, Zn, Cd, Hg, Sn, As, Sb, Se, Br, Sc, La, Sm, Eu, Tb, Hf, Ta, and Th were measured in urine specimens from the Apollo 17 astronauts by neutron activation analysis. Strontium, barium, gold, cadmium, lanthanum, samarium, europium, terbium, thorium, and tin are reported for the first time. The concentrations or excretion rates of bromine and the alkali metals exhibit singificantly reduced postflight levels and are generally lower than values observed for previous missions. Chromium concentrations reflect radiochromium injections.

  5. Annual report in compliance with the reactor sharing program, September 1, 1994--August 31, 1995

    SciTech Connect

    Karam, R.A.

    1997-04-01

    This report contains information with regard to facilities utilization, descriptions (brief), personnel, organization, and programs of the Neely Nuclear Research Center (NNRC) at the Georgia Institute of Technology. The NNRC has two major facilities: the Georgia Tech Research Reactor and the Hot Cell Laboratory. This report of NNRC utilization is prepared in compliance with the contract requirements between the U.S. Department of Energy and the Georgia Institute of Technology. The NNRC is a participant in the University Reactor Sharing Program; as such, it makes available its 5 MW research reactor, its Co-60 irradiation facility and its activation analysis laboratory to large numbers of students and faculty from many universities and colleges.

  6. Prediction and measurement results of radiation damage to CMOS devices on board spacecraft

    NASA Technical Reports Server (NTRS)

    Stassinopoulos, E. G.; Danchenko, V.; Cliff, R. A.; Sing, M.; Brucker, G. J.; Ohanian, R. S.

    1977-01-01

    Final results from the CMOS Radiation Effects Measurement (CREM) experiment flown on Explorer 55 are presented and discussed, based on about 15 months of observations and measurements. Conclusions are given relating to long-range annealing, effects of operating temperature on semiconductor performance in space, biased and unbiased P-MOS device degradation, unbiased n-channel device performance, changes in device transconductance, and the difference in ionization efficiency between Co-60 gamma rays and 1-Mev Van de Graaff electrons. The performance of devices in a heavily shielded electronic subsystem box within the spacecraft is evaluated and compared. Environment models and computational methods and their impact on device-degradation estimates are being reviewed to determine whether they permit cost-effective design of spacecraft.

  7. Radiation effect on silicon transistors in mixed neutrons-gamma environment

    NASA Astrophysics Data System (ADS)

    Assaf, J.; Shweikani, R.; Ghazi, N.

    2014-10-01

    The effects of gamma and neutron irradiations on two different types of transistors, Junction Field Effect Transistor (JFET) and Bipolar Junction Transistor (BJT), were investigated. Irradiation was performed using a Syrian research reactor (RR) (Miniature Neutron Source Reactor (MNSR)) and a gamma source (Co-60 cell). For RR irradiation, MCNP code was used to calculate the absorbed dose received by the transistors. The experimental results showed an overall decrease in the gain factors of the transistors after irradiation, and the JFETs were more resistant to the effects of radiation than BJTs. The effect of RR irradiation was also greater than that of gamma source for the same dose, which could be because neutrons could cause more damage than gamma irradiation.

  8. Aging of nuclear power plant safety cables

    SciTech Connect

    Gillen, K.T.; Salazar, E.A.

    1986-01-01

    Results from an extensive aging program on polymeric materials stripped from unused nuclear reactor safety cables are described. Mechanical damage was monitored after room temperature aging in a Co-60 gamma radiation source at various humidities and radiation dose rates ranging from 1.2 Mrad/h to 2 krad/h. For chloroprene, chlorosulfonated polyethylene, and silicone materials, the mechanical degradation was found to depend only on the total integrated radiation dose, implying that radiation dose rate effects are small. On the other hand, strong evidence for radiation dose rate effects were found for an ethylene propylene rubber material and a cross-linked polyolefin material. Humidity effects were determined to be insignificant for all the materials studied.

  9. Flux measurements in a nuclear research reactor by using an aluminum nitride detector

    NASA Astrophysics Data System (ADS)

    Moon, B. S.; Yoo, D. S.; Hwang, I. K.; Chung, C. E.; Holcomb, D. E.

    2007-08-01

    A small polycrystalline aluminium nitride detector with a thickness of 381 μm was used to measure a 200,000 Ci Co 60 source and to measure the flux in a research reactor where the neutron flux is about 10 14/cm 2 s, which is nearly the same order as in the commercial power plant. If the applied voltage is greater than or equal to 2000 V and if the measurements are done in a short period of time so that the heat energy does not build up in the aluminium nitride, then the measured electric current is linearly proportional to the input flux. It is assumed of course that the energy spectrum of the input flux remains constant. This linearity relation is illustrated by the results of a measurement in which the reactor power has been controlled so that the flux becomes a step function.

  10. Radiation-induced mutagenicity and lethality in Salmonella typhimurium

    SciTech Connect

    Isildar, M.; Bakale, G.

    1983-01-01

    The mutagenic and lethal effects of ionizing radiation on histidine-deficient auxotrophs of Salmonella typhimurium were studied to improve the understanding of radiation damage to DNA. The auxotrophs were divided into two groups - one which is sensitive to base-pair substitutions and another sensitive to frameshifts. These groups were composed of parent-daughter pairs in which the chemical mutagenicity enhancing plasmid, pKM101, is absent in the parent strain and present in the daughter. Co-60 ..gamma..-radiation and 250 kV x-rays were used to irradiate the bacteria. Irradiation of the frameshift - sensitive strains which carry the pKm101 plasmid doubled the absolute number of induced revertants whereas irradiation of the base-pair substitution sensitive strain which also carries the pKm101 plasmid produced nearly no change in the number of induced revertants. A nearly negligible effect on the mutation rate was observed for all parent strains. (ACR)

  11. The development of non-uniform deposition of holes in gate oxides

    SciTech Connect

    Freitag, R.K.; Dozier, C.M.; Brown, D.B.; Burke, E.A.

    1988-12-01

    The subthreshold technique was used to study irradiated MOS transistors at 80 K. Stretchout of the subthreshold curve demonstrated production of lateral non-uniformities (LNUs) in the hole distribution. The LNUs were analyzed in terms of (a) a parallel transistor model, and (b) the statistics of the non-uniform distribution of dose deposition in the SiO/sub 2/. The results confirm the hypothesis that at 80 K the principal source of LNUs is the granularity in dose deposition. The relative standard deviation for the deposited dose is larger for thin oxides, for 10 kev x-rays (as opposed to Co-60), and at low doses. These physical phenomena are predicted to have a significant effect at room temperature also.

  12. Environmental radionuclide concentrations in the vicinity of the peach bottom atomic power station: 1985-1986. Data report

    SciTech Connect

    Domotor, S.L.; McLean, R.I.

    1989-07-01

    High-resolution gamma spectroscopy was used to determine radionuclide concentrations in over 450 biota and sediment samples collected from the Susquehanna River-Chesapeake Bay system in the vicinity of the Peach Bottom Atomic Power Station (PBAPS) during 1985-1986. Low concentrations of PBAPS-related radionuclides (Zn65, Cs-134, and Cs-137) were detected in finfish, mussels, and crayfish. These PBAPS-related radionuclides and Co-60 were also detected in sediments. I-131 attributable to the Chernobyl reactor accident (April 26, 1986) was detected in environmental samples collected in May 1986. PBAPS-related radionuclide concentrations in biota and sediments represent small increments to the Susquehanna River-Chesapeake Bay system relative to natural and weapons test levels; radionuclide releases by PBAPS, and radiation doses to man, are well within regulatory limits.

  13. Application of a Pelletron accelerator to study total dose radiation effects on 50 GHz SiGe HBTs

    NASA Astrophysics Data System (ADS)

    Praveen, K. C.; Pushpa, N.; Naik, P. S.; Cressler, John D.; Tripathi, Ambuj; Gnana Prakash, A. P.

    2012-02-01

    We have investigated the effects of 50 MeV lithium ion irradiation on the DC electrical characteristics of first-generation silicon-germanium heterojunction bipolar transistors (50 GHz SiGe HBTs) in the dose range of 600 krad to 100 Mrad. The results of 50 MeV Li 3+ ion irradiation on the SiGe HBTs are compared with 63 MeV proton and Co-60 gamma irradiation results in the same dose range in order to understand the damage induced by different LET species. The radiation response of emitter-base (EB) spacer oxide and shallow trench isolation (STI) oxide to different irradiation types are discussed in this paper. We have also focused on the efficacy in the application of a Pelletron accelerator to study total dose irradiation studies in SiGe HBTs.

  14. INDEPENDENT CONFIRMATORY SURVEY OF THE NUCLEAR RESEARCH LABORATORY AT THE UNIVERSITY OF ILLINOIS URBANA-CHAMPAIGN, ILLINOIS

    SciTech Connect

    EVAN M. HARPENAU

    2012-06-28

    ORAU conducted confirmatory survey activities within the NRL at the University during the week of May 7, 2012. The survey activities included visual inspections/ assessments, surface activity measurements, and volumetric concrete sampling activities. During the course of the confirmatory activities, ORAU noted several issues with the survey-for-release activities performed at the University. Issues included inconsistencies with: survey unit classifications were not designated according to Multi-Agency Radiation Survey and Site Investigation Manual guidance; survey instrument calibrations were not representative of the radionuclides of concern; calculations for instrumentation detection capabilities did not align with the release criteria discussed in the licensee’s survey guidance documents; total surface activity measurements were in excess of the release criteria; and Co-60 and Eu-152 concentrations in the confirmatory concrete samples were above their respective guidelines. Based on the significant programmatic issues identified, ORAU cannot independently conclude that the NRL satisfied the requirements and limits for release of materials without radiological restrictions.

  15. Radiation studies of optical and electronic components used in astronomical satellite studies

    NASA Technical Reports Server (NTRS)

    Becher, J.; Kernell, R. L.

    1981-01-01

    The synchronous orbit of the IUE carries the satellite through Earth's outer electron belt. A 40 mCi Sr90 source was used to simulate these electrons. A 5 mCi source of Co60 was used to simulate bremmstrahlung. A 10 MeV electron Linac and a 1.7 MeV electron Van de Graaf wer used to investigate the energy dependence of radiation effects and to perform radiations at a high flux rate. A 100 MeV proton cyclotron was used to simulate cosmic rays. Results are presented for three instrument systems of the IUE and measurements for specific components are reported. The three instrument systems were the ultraviolet converter, the fine error sensor (FES), and the SEC vidicon camera tube. The components were optical glasses, electronic components, silicon photodiodes, and UV window materials.

  16. Guidelines for using a 10-keV x-ray source for hardness assurance

    SciTech Connect

    Fleetwood, D.M.

    1986-01-01

    In this paper, work done at Sandia is summarized that demonstrates that it is possible to use a 10-keV x-ray source for hardness assurance. Transistor data is presented that shows that a 10-keV x-ray source can be used as a reliable process monitor, in the sense that Co-60 part response can be predicted easily and reliably from x-ray part response. Further, test structure and functional part data is presented that illustrates how an x-ray source may be employed for wafer lot acceptance for silicon-gate CMOS devices that either employ quardbands or hardened field oxides for device isolation. Finally, a few words are said about the use of high-Z gate metallizations. These results should provide guidelines for implementation of lot acceptance testing with a 10-keV x-ray source.

  17. Influence of gamma radiation on the colour strength and fastness properties of fabric using turmeric (Curcuma longa L .) as natural dye

    NASA Astrophysics Data System (ADS)

    Bhatti, Ijaz A.; Adeel, Shahid; Jamal, M. Asghar; Safdar, Muhammad; Abbas, Muhammad

    2010-05-01

    The effect of gamma radiation on the dyeing of cotton with extract of turmeric ( Curcuma longa L.) powder has been investigated. Cotton fabric and turmeric powder were irradiated to absorbed doses of 1, 2, 3, 4 and 6 kGy using Co-60 gamma irradiator. Dyeing parameters such as temperature, pH and mordant concentration were optimized. Dyeing was performed using un-irradiated and irradiated cotton with the extracts of un-irradiated and irradiated turmeric powder in order to investigate the effect of radiation treatment on the colour strength of dyed fabric. The reported data of un-irradiated and irradiated fabrics dyed with un-irradiated and irradiated dyes were obtained using the spectraflash SF-650. The colourfastness to light, rubbing- and washing-fastness properties showed that gamma irradiation has improved the dyeing characteristics from fair to good.

  18. Mechanisms of radio-protection by catecholamines in the hamster /Mesocricetus auratus/

    NASA Technical Reports Server (NTRS)

    Prewitt, R. L.; Musacchia, X. J.

    1975-01-01

    Experiments were conducted on normal and splenectomized male and female hamsters between 2 and 3 months old subjected to a whole-body exposure of 1000 or 2000 rads in a Co-60 source with a view toward evaluating their radio-protection by norepinephrine, isoproterenol, and phenylephrine. Vasoconstriction hypoxia mechanism of radio-protection is examined along with the hypothesis that isoproterenol protects by hypercalcemia-induced cell proliferation. Radiation experiment results are found to be consistent with the hypothesis that stimulation of alpha receptors results in radio-protection through a tissue hypoxia mechanism. Beta agonists seem to protect by a hypotensive-hypoxia mechanism. The catecholamines protect against the hematopoietic syndrome, but show no evidence of protection against the gastrointestinal syndrome.

  19. Gamma ray spectrometry of LDEF samples at SRS

    NASA Technical Reports Server (NTRS)

    Winn, Willard G.

    1991-01-01

    A total of 31 samples from Long Duration Exposure Facility (LDEF), including materials of Al, V, and steel trunnions were analyzed by ultralow level gamma spectrometry. The study quantified particle induced activations of Na-22, Sc-46, Cr-51, Mn-54, Co-56, Co-57, Co-58, and Co-60. The samples of trunnion sections exhibited increasing activity toward the outer end of the trunnion and decreasing activity toward its radial center. The trunnion sections did not include an end piece that collects noticeable Be-7 on its leading surface. No significant Be-7 was detected in the samples analyzed. The most sensitive analyses were performed with a 90 pct. efficient HPGe gamma ray detector, which is enclosed in a purged active/passive active shield.

  20. The fall, recovery and classification of the Park Forest Meteorite

    SciTech Connect

    Simon, Steve B.; Grossman, Larry; Clayton, Robert N.; Mayeda, T. K.; Schwade, J. R.; Sipiera, P. P.; Wacker, John F.; Wadhwa, M.

    2004-04-01

    On the night of March 26, 2003, a large meteorite broke up and fell upon the south suburbs of Chicago. The name Park Forest, for the village that is at the center of the strewnfield, has been approved by the Nomenclature Committee of the Meteoritical Society. Satellite data indicate that the bolide traveled from the southwest toward the northeast. The strewnfield has a southwest-northwest trend, however, probably due to the effects of strong weterly winds at high altitudes. Its very low Co-56 and very high Co-60 activities indicate that Park Forest had a preatmospheric mass that was at least ~900 kg and could bave been as large as ~7000 kg, of which only ~30 kg have been recovered. This paper describes initial measurements to identify and characterize the Park Forest meteorite, which is classified as an L5 chondrite.

  1. Cosmogenic radionuclides in stone meteorites

    NASA Technical Reports Server (NTRS)

    Cressy, P. J., Jr.

    1976-01-01

    This document presents the techniques and compilation of results of cosmogenic Al-26 measurements at Goddard Space Flight Center on 91 samples of 76 stone meteorites. Short-lived radionuclides, including Na-22, Sc-46, Mn-54, and Co-60, were measured in 13 of these meteorites. About one-third of these data has not previously been published. The results are discussed briefly in terms of (1) depletion of Al-26 and natural potassium due to weathering, (2) possible exposure of several chondrites to an unusually high cosmic-ray flux, (3) comparison of Al-26, Na-22, Sc-46, and Mn5-54 in chondrites with the spallation Ne-22/Ne-21 ratio as a shielding indicator, and (4) comparison of (Al-26)-(Ne-22)/Ne-21 data for achondrite classes with the chondrite trend.

  2. Analysis of Iron Meteorites Using Computed Tomography and Electron-probe Microanalysis

    NASA Technical Reports Server (NTRS)

    Carpenter, P. K.; Gillies, D. C.

    2005-01-01

    Computed tomography (CT) imaging and electron-probe microanalysis (EPMA) have been used to study samples of the Mundrabilla and Colomera iron meteorites in order to perform structural, textural, and mineralogical analysis. Both gamma-ray (Co-60 source, essentially monochromatic 1.25MeV avg.) and x-ray (420 KeV, continuous) sources have been used, with effective resolution of approximately 1 mm and 0.25 mm, respectively. The gamma-ray source provides approx. 15 cm penetration through steel and is used for larger samples, whereas the x-ray source provides superior resolution at reduced penetration but exhibits beam hardening artifacts. Here we present a combined approach where CT and EPMA imaging and microanalysis aid in the identification of structural and compositional features in iron meteorites.

  3. Response of the alanine/ESR dosimeter to radiation from an Ir-192 HDR brachytherapy source

    NASA Astrophysics Data System (ADS)

    Anton, M.; Hackel, T.; Zink, K.; von Voigts-Rhetz, P.; Selbach, H.-J.

    2015-01-01

    The response of the alanine dosimeter to radiation from an Ir-192 source with respect to the absorbed dose to water, relative to Co-60 radiation, was determined experimentally as well as by Monte Carlo simulations. The experimental and Monte Carlo results for the response agree well within the limits of uncertainty. The relative response decreases with an increasing distance between the measurement volume and the source from approximately 98% at a 1 cm distance to 96% at 5 cm. The present data are more accurate, but agree well with data published by Schaeken et al (2011 Phys. Med. Biol. 56 6625-34). The decrease of the relative response with an increasing distance that had already been observed by these authors is confirmed. In the appendix, the properties of the alanine dosimeter with respect to volume and sensitivity corrections are investigated. The inhomogeneous distribution of the detection probability that was taken into account for the analysis was determined experimentally.

  4. Natural diatomite process for removal of radioactivity from liquid waste.

    PubMed

    Osmanlioglu, Ahmet Erdal

    2007-01-01

    Diatomite has a number of unique physical properties and has found diversified industrial utilization. The filtration characteristics are particularly significant in the purification of liquids. The purpose of this study was to test natural diatomaceous earth (diatomite) as an alternative material that could be used for removal of radioactivity from liquid waste. A pilot-scale column-type device was designed. Natural diatomite samples were ground, sieved and prepared to use as sorption media. In this study, real waste liquid was used as radioactive liquid having special conditions. The liquid waste contained three radionuclides (Cs-137, Cs-134 and Co-60). Following the treatment by diatomite, the radioactivity of liquid waste was reduced from the initial 2.60 Bq/ml to less than 0.40 Bq/ml. The results of this study show that most of the radioactivity was removed from the solution by processing with diatomite. PMID:17049259

  5. Present and Future Technology for Simultaneous Superficial Thermoradiotherapy of Breast Cancer

    PubMed Central

    Moros, Eduardo G.; Peñagaricano, Jose; Novàk, Petr; Straube, William L.; Myerson, Robert J.

    2010-01-01

    This paper reviews systems and techniques to deliver simultaneous thermoradiotherapy of breast cancer. It first covers the clinical implementation of simultaneous delivery of superficial (microwave or ultrasound) hyperthermia and external photon beam radiotherapy, first using a Co-60 teletherapy unit and later medical linear accelerators. The parallel development and related studies of the SURLAS, an advanced system specifically designed and developed for simultaneous thermoradiotherapy, follows. The performance characteristics of the SURLAS are reviewed and power limitation problems at high acoustic frequencies (> 3MHz) are discussed along with potential solutions. Next, the feasibility of simultaneous SURLAS hyperthermia and IMRT/IGRT is established based on published and newly presented studies. Finally, based on the encouraging clinical results thus far, it is concluded that new trials employing the latest technologies are warranted along with further developments in treatment planning. PMID:20849263

  6. 10 CFR Appendix E to Part 835 - Values for Establishing Sealed Radioactive Source Accountability and Radioactive Material Posting...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...-41 9.3E+06 Ca-45 1.1E+06 Sc-46 6.2E+01 Ti-44 1.5E+02 V-49 1.0E+08 Mn-53 7.5E+07 Mn-54 6.5E+01 Fe-55 2.9E+06 Fe-59 1.9E+02 Fe-60 8.1E+03 Co-56 3.9E+01 Co-57 2.3E+02 Co-58 1.3E+02 Co-60 1.7E+01 Ni-59 3.2E+06 Ni-63 1.3E+06 Zn-65 1.1E+02 Ge-68 5.6E+02 As-73 5.3E+02 Se-75 6.3E+01 Se-79 8.7E+05 Rb-83...

  7. 10 CFR Appendix E to Part 835 - Values for Establishing Sealed Radioactive Source Accountability and Radioactive Material Posting...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...-41 9.3E+06 Ca-45 1.1E+06 Sc-46 6.2E+01 Ti-44 1.5E+02 V-49 1.0E+08 Mn-53 7.5E+07 Mn-54 6.5E+01 Fe-55 2.9E+06 Fe-59 1.9E+02 Fe-60 8.1E+03 Co-56 3.9E+01 Co-57 2.3E+02 Co-58 1.3E+02 Co-60 1.7E+01 Ni-59 3.2E+06 Ni-63 1.3E+06 Zn-65 1.1E+02 Ge-68 5.6E+02 As-73 5.3E+02 Se-75 6.3E+01 Se-79 8.7E+05 Rb-83...

  8. 10 CFR Appendix E to Part 835 - Values for Establishing Sealed Radioactive Source Accountability and Radioactive Material Posting...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...-41 9.3E+06 Ca-45 1.1E+06 Sc-46 6.2E+01 Ti-44 1.5E+02 V-49 1.0E+08 Mn-53 7.5E+07 Mn-54 6.5E+01 Fe-55 2.9E+06 Fe-59 1.9E+02 Fe-60 8.1E+03 Co-56 3.9E+01 Co-57 2.3E+02 Co-58 1.3E+02 Co-60 1.7E+01 Ni-59 3.2E+06 Ni-63 1.3E+06 Zn-65 1.1E+02 Ge-68 5.6E+02 As-73 5.3E+02 Se-75 6.3E+01 Se-79 8.7E+05 Rb-83...

  9. 10 CFR Appendix E to Part 835 - Values for Establishing Sealed Radioactive Source Accountability and Radioactive Material Posting...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...-41 9.3E+06 Ca-45 1.1E+06 Sc-46 6.2E+01 Ti-44 1.5E+02 V-49 1.0E+08 Mn-53 7.5E+07 Mn-54 6.5E+01 Fe-55 2.9E+06 Fe-59 1.9E+02 Fe-60 8.1E+03 Co-56 3.9E+01 Co-57 2.3E+02 Co-58 1.3E+02 Co-60 1.7E+01 Ni-59 3.2E+06 Ni-63 1.3E+06 Zn-65 1.1E+02 Ge-68 5.6E+02 As-73 5.3E+02 Se-75 6.3E+01 Se-79 8.7E+05 Rb-83...

  10. 10 CFR Appendix E to Part 835 - Values for Establishing Sealed Radioactive Source Accountability and Radioactive Material Posting...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...-41 9.3E+06 Ca-45 1.1E+06 Sc-46 6.2E+01 Ti-44 1.5E+02 V-49 1.0E+08 Mn-53 7.5E+07 Mn-54 6.5E+01 Fe-55 2.9E+06 Fe-59 1.9E+02 Fe-60 8.1E+03 Co-56 3.9E+01 Co-57 2.3E+02 Co-58 1.3E+02 Co-60 1.7E+01 Ni-59 3.2E+06 Ni-63 1.3E+06 Zn-65 1.1E+02 Ge-68 5.6E+02 As-73 5.3E+02 Se-75 6.3E+01 Se-79 8.7E+05 Rb-83...

  11. Feasibility of Ultra-Thin Fiber-Optic Dosimeters for Radiotherapy Dosimetry

    PubMed Central

    Lee, Bongsoo; Kwon, Guwon; Shin, Sang Hun; Kim, Jaeseok; Yoo, Wook Jae; Ji, Young Hoon; Jang, Kyoung Won

    2015-01-01

    In this study, prototype ultra-thin fiber-optic dosimeters were fabricated using organic scintillators, wavelength shifting fibers, and plastic optical fibers. The sensor probes of the ultra-thin fiber-optic dosimeters consisted of very thin organic scintillators with thicknesses of 100, 150 and 200 μm. These types of sensors cannot only be used to measure skin or surface doses but also provide depth dose measurements with high spatial resolution. With the ultra-thin fiber-optic dosimeters, surface doses for gamma rays generated from a Co-60 therapy machine were measured. Additionally, percentage depth doses in the build-up regions were obtained by using the ultra-thin fiber-optic dosimeters, and the results were compared with those of external beam therapy films and a conventional fiber-optic dosimeter. PMID:26593917

  12. Thermoluminescence property of nano scale Al2O3: C by combustion method

    NASA Astrophysics Data System (ADS)

    Bharthasaradhi, R.; Nehru, L. C.

    2016-05-01

    In this study, thermoluminescence dosimetry material of carbon doped aluminium oxide by combustion method using Aluminium nitrate and Glycine. The Structure of the prepared Sample was carried out by XRD. The sample was nano crystalline in nature. Having hexagonal structure with unit cell parameters a=4.75Å, C=12.99Å. The surface morphology of the prepared nanopowder was carried out through (SEM). The morphology of the prepared sample is platelet structure and functional group analysis carried out through FT-IR Spectrum. The prepared sample was irradiated through γ-ray CO60 (100Gy) was used as γ-ray source. The thermoluminescence glow curve of the irradiated sample showed an isolated peak at around 200°C. The result suggest the prepared nanopowder is suitable for medical radiation dosimetry.

  13. Axtrell, a new CV3 chondrite find from Texas

    NASA Technical Reports Server (NTRS)

    Simon, S. B.; Grossman, L.; Casanova, I.; Symes, S.; Benoit, P.; Sears, D. W. G.; Wacker, J. F.

    1995-01-01

    We describe a previously unreported meteorite found in Axtell, Texas, in 1943. Based on the mineralogical composition and texture of its matrix and the sizes and abundance of chondrules, we classify it as a CV3 carbonaceous chondrite. The dominant opaque phase in the chondrules is magnetite, and that in refractory inclusions is Ni-rich metal (awaruite). Axtell, therefore, belongs to the oxidized subgroup of CV3 chondrites, although unlike Allende it escaped strong sulfidation. The meteorite bears a strong textural resemblance to Allende, and its chondrule population and matrix appear to be quite similar to those of Allende, but its refractory inclusions, thermoluminescence properties, and cosmogenic Co-60 abundances are not. Our data are consistent with a terrestrial age for Axtell of approximately 100 years and a metamorphic grade slightly lower than that of Allende.

  14. Thermoluminescence response of Ge-doped SiO2 fibres to electrons, X- and γ-radiation

    NASA Astrophysics Data System (ADS)

    Entezam, A.; Khandaker, M. U.; Amin, Y. M.; Ung, N. M.; Maah, J.; Bradley, D. A.

    2016-04-01

    For doses from 10 cGy to 80 Gy, we investigate the thermoluminescence (TL) response of tailor-made Ge-doped SiO2 fibres for accelerated electrons (6, 12 and 20 MeV), megavoltage X-rays (6, 10 MV) and 1.25 MeV γ-rays, delivered by a linear accelerator (LINAC) and a Co-60 irradiator respectively. Fibres of various dimensions were fabricated, obtained with doping concentrations from 6% to 10% Ge. The fibres are observed to provide a linear response with radiation dose, an overall reproducibility of 1-5%, and inappreciable dependence on energy, field-size and angular variation. For fibres exposed to 6 MV X-rays, the response increases with core size, the 6% Ge-doped fibres providing the greatest TL yield. The fibres exhibit uniformity of response and provide the basis of a promising TL system for radiotherapy applications, offering high spatial resolution and sensitivity.

  15. Study of free radicals in gamma irradiated cellulose of cultural heritage materials using Electron Paramagnetic Resonance

    NASA Astrophysics Data System (ADS)

    Kodama, Yasko; Rodrigues, Orlando, Jr.; Garcia, Rafael Henrique Lazzari; Santos, Paulo de Souza; Vasquez, Pablo A. S.

    2016-07-01

    Main subject of this article was to study room temperature stable radicals in Co-60 gamma irradiated contemporary paper using Electron Paramagnetic Resonance spectrometer (EPR). XRD was used to study the effect of ionizing radiation on the morphology of book paper. SEM images presented regions with cellulose fibers and regions with particles agglomeration on the cellulose fibers. Those agglomerations were rich in calcium, observed by EDS. XRD analysis confirmed presence of calcium carbonate diffraction peaks. The main objective of this study was to propose a method using conventional kinetics chemical reactions for the observed radical formed by ionizing radiation. Therefore, further analyses were made to study the half-life and the kinetics of the free radical created. This method can be suitably applied to study radicals on cultural heritage objects.

  16. Improvement of colour strength and colourfastness properties of gamma irradiated cotton using reactive black-5

    NASA Astrophysics Data System (ADS)

    Ahmad Bhatti, Ijaz; Adeel, Shahid; Nadeem, Raziya; Asghar, Toheed

    2012-03-01

    The dyeing behaviour of gamma irradiated cotton fabric using Reactive Black-5 dye powder has been investigated. The mercerized, bleached and plain weaved cotton fabric was irradiated to different absorbed doses of 100, 200, 300, 400, 500 and 600 Gy using Co-60 gamma irradiator. Dyeing was performed using irradiated and un-irradiated cotton with dye solutions. The dyeing parameters such as temperature of dyeing, time of dyeing and pH of dyeing solutions were optimised. The colour strength values of dyed fabrics were evaluated by comparing irradiated and un-irradiated cotton in CIE Lab system using Spectra flash SF650. Methods suggested by International Standard Organisation (ISO) were employed to study the effect of gamma irradiation on the colourfastness properties of dyed fabric. It is found that gamma irradiated cotton dyed with Reactive Black-5 has not only improved the colour strength but also enhanced the rating of fastness properties.

  17. Metal Surface Decontamination by the PFC Solution

    SciTech Connect

    Hui-Jun Won; Gye-Nam Kim; Wang-Kyu Choi; Chong-Hun Jung; Won-Zin Oh

    2006-07-01

    PFC (per-fluorocarbon) spray decontamination equipment was fabricated and its decontamination behavior was investigated. Europium oxide powder was mixed with the isotope solution which contains Co-60 and Cs-137. The different shape of metal specimens artificially contaminated with europium oxide powder was used as the surrogate contaminants. Before and after the application of the PFC spray decontamination method, the radioactivity of the metal specimens was measured by MCA. The decontamination factors were in the range from 9.6 to 62.4. The spent PFC solution was recycled by distillation. Before and after distillation, the turbidity of PFC solution was also measured. From the test results, it was found that more than 98% of the PFC solution could be recycled by a distillation. (authors)

  18. Radionuclides in Chesapeake Bay sediments

    NASA Technical Reports Server (NTRS)

    Cressy, P. J., Jr.

    1976-01-01

    Natural and manmade gamma-ray emitting radionuclides were measured in Chesapeake Bay sediments taken near the Calvert Cliffs Nuclear Power Plant site. Samples represented several water depths, at six locations, for five dates encompassing a complete seasonal cycle. Radionuclide contents of dry sediments ranged as follows: Tl-208, 40 to 400 pCi/kg; Bi-214, 200 to 800 pCi/kg; K, 0.04 to 2.1 percent; Cs-137 5 to 1900 pCi/kg; Ru106, 40 to 1000 pCikg Co60, 1 to 27 pCi/kg. In general, radionuclide contents were positively correlated with each other and negatively correlated with sediment grain size.

  19. Radiological Control of Water in Reactor Pond of MR Reactor in NRC 'Kurchatov Institute', During Dismantling Work - 13462

    SciTech Connect

    Stepanov, Alexey; Simirsky, Yury; Semin, Ilya; Volkovich, Anatoly; Ivanov, Oleg

    2013-07-01

    The analysis of the activity and radionuclide composition of water from the MR reactor pond for α,β,γ-ray radionuclides was made. To solve this problem we use a wide range of laboratory equipment: gamma spectrometric complex, beta spectrometric complex, vacuum alpha spectrometer, and spectrometric complex with liquid scintillator. The water from MR reactor pond contains: Cs-137 (2,6*10{sup 2} Bq/g), Co-60(1,8 Bq/g), Sr-90 (1,0*10{sup 2} Bq/g), H-3 (7,0*10{sup 3} Bq/g), and components of nuclear fuel (U-232,U-234,U-235,U-236,U-238). Therefore the cleaning water from radioactivity waste occurs to be quite a complicated radiochemical task. (authors)

  20. Radiation grafting studies of acrylic acid onto cellulose triacetate membranes

    NASA Astrophysics Data System (ADS)

    Mazzei, R. O.; Smolko, E.; Torres, A.; Tadey, D.; Rocco, C.; Gizzi, L.; Strangis, S.

    2002-05-01

    Polymer surface modifications were obtained by the application of radiation treatments, etching and grafting of acrylic acid monomers on different membranes of cellulose triacetate materials. Cellulose triacetate foils from pellet dissolution and commercial cellulose triacetate solid state nuclear track detector membranes were assayed. Irradiation with fission fragments from Cf-252 source to obtain a porous structure, 25 MeV proton beam and Co-60 γ-source to produce peroxides were employed in the experiments. The present work gives the grafting yield of AAc monomer onto CTA membranes as a function of diverse variables including irradiation parameters ( γ-dose, Cf-252 ff irradiation time, proton fluency and electronic energy loss (d E/d x) e), structural parameters (pore diameter and pore density, etching time and etching temperature) and grafting parameters (monomer and Mohr salt concentration, grafting time and grafting temperature).

  1. Physicochemical, thermal and pasting characteristics of gamma irradiated rice starches.

    PubMed

    Gul, Khalid; Singh, A K; Sonkawade, R G

    2016-04-01

    Starches isolated from two recently released rice cultivars (PR 121 and PR 116) grown in sub-tropical climates of Punjab, India were subjected to gamma irradiation at 0, 2, and 10kGy doses using a Co(60) irradiator source. Physicochemical, thermal, pasting, and morphological properties were studied. Irradiation resulted in a significant decrease in apparent amylose content, swelling power and pasting properties. Carboxyl content and solubility increased with irradiation. The granule morphology was evaluated using scanning electron microscope, particle size analyzer and light microscope. Irradiation resulted in formation of small size granules. Granules were irregular and polyhedral in shape. The granule morphology and A-type X-ray diffraction pattern were not altered by irradiation. PMID:26778155

  2. Cataract production in mice by heavy charged particles

    NASA Technical Reports Server (NTRS)

    Ainsworth, E. J.; Jose, U.; Yang, V. V.; Barker, M. E.

    1981-01-01

    The cataractogenic effects of heavy charged particles are evaluated in mice in relation to dose and ionization density. The relative biological effectiveness in relation to linear energy transfer for various particles is considered. Results indicated that low single doses (5 to 20 rad) of Fe 56 or Ar 40 particles are cataractogenic at 11 to 18 months after irradiation; onset and density of the opacification are dose related and cataract density (grade) at 9, 11, 13, and 16 months after irradiation shows partial linear energy transfer dependence. The severity of cataracts is reduced significantly when 417 rad of Co 60 gamma radiation is given in 24 weekly 17 rad fractions compared to giving this radiation as a single dose, but cataract severity is not reduced by fractionation of C12 doses over 24 weeks.

  3. Interim Safe Storage of Plutonium Production Reactors at the US DOE Hanford Site - 13438

    SciTech Connect

    Schilperoort, Daryl L.; Faulk, Darrin

    2013-07-01

    Nine plutonium production reactors located on DOE's Hanford Site are being placed into an Interim Safe Storage (ISS) period that extends to 2068. The Environmental Impact Statement (EIS) for ISS [1] was completed in 1993 and proposed a 75-year storage period that began when the EIS was finalized. Remote electronic monitoring of the temperature and water level alarms inside the safe storage enclosure (SSE) with visual inspection inside the SSE every 5 years are the only planned operational activities during this ISS period. At the end of the ISS period, the reactor cores will be removed intact and buried in a landfill on the Hanford Site. The ISS period allows for radioactive decay of isotopes, primarily Co-60 and Cs-137, to reduce the dose exposure during disposal of the reactor cores. Six of the nine reactors have been placed into ISS by having an SSE constructed around the reactor core. (authors)

  4. Analytical modeling for gamma radiation damage on silicon photodiodes

    NASA Astrophysics Data System (ADS)

    Jafari, H.; Feghhi, S. A. H.

    2016-04-01

    Radiation-induced damage in PIN silicon photodiode induces degradation of the photodiode parameters. In this work, by presenting an analytical model, the effect of gamma dose on the dark current in a PIN photodiode array was investigated. Geant4 was used to obtain the damage constant as a result of primary incident particle fluence and NIEL distribution calculations. Experimental measurements as well as numerical simulation of the semiconductor with ATLAS were carried out to verify and parameterize the analytical model calculations. A reasonable agreement has been found between analytical results and experimental data for BPX65 silicon photodiodes irradiated by a Co-60 gamma source at total doses up to 500 krad under different reverse voltages. Moreover, the results showed that the dark current of each photodiode array pixel has considerably increased by gamma dose irradiation.

  5. Estimation of Anomalous Single Scatter Events in XENON100 Data

    NASA Astrophysics Data System (ADS)

    Lim, Kyungeun; Xenon100 Collaboration

    2011-04-01

    Anomalous single scatter events in XENON100 are events that have only one scintillation pulse (S1) and one ionization pulse (S2), but are multiple scatters in nature. Only one scatter takes place inside the detector's charge and light sensitive volume, resulting in a S2/S1 ratio that is lower than that of true single scatter events and typical of that expected from a WIMP interaction. The identification and suppression of these anomalous events is therefore essential for a sensitive dark matter search. I present results from a Monte Carlo (MC) study that was carried out to estimate the expected number of anomalous single scatter events in the XENON100 WIMP search data. The MC was validated with a comparison with Co-60 gamma-calibration data. We gratefully acknowledge support from NSF, DOE, SNF, the Volkswagen Foundation, FCT, and STCSM. We are grateful to the LNGS for hosting and supporting the XENON program.

  6. Predicting long-lived, neutron-induced activation of concrete in a cyclotron vault

    NASA Astrophysics Data System (ADS)

    Carroll, L. R.

    2001-07-01

    Many elements in concrete can become activated by neutrons in a cyclotron vault, but only a few of the activation products are long-lived. The most prominent of these are Eu-152, Eu-154, Co-60, and Cs-134 which build up over time from (n, γ) reactions in trace amounts of stable Europium, Cobalt, and Cesium that are normally present in concrete in concentrations of a few parts per million, or less, by weight. A retrospective analysis of data taken in connection with a previous decommissioning of a cyclotron vault, coupled with independent published data, gives us an estimate of the concentrations of these elements in concrete. With that estimate as a benchmark, we then employ a Monte Carlo Radiation Transport Code to estimate the long-term activation profile in concrete for arbitrary irradiation conditions.

  7. Deposition of cobalt on surface-treated stainless steel under PWR conditions

    SciTech Connect

    Lister, D.H.; Anderson, P.G.; Barry, B.J.; Lavoie, R.G. . Chalk River Nuclear Labs.)

    1989-10-01

    As part of an on-going program aimed at reducing radiation exposures in light water reactors, the modification of surfaces to minimize their propensity to pick up radioactivity under reactor conditions has been studied. This report describes how stainless steel specimens, surface-treated with a variety of processes, picked up Co-60 from high-temperature water under PWR conditions in a high-pressure loop. The build-up of activity was monitored on-line with a movable gamma spectrometer. Off-line counting at the end of the experiment established the absolute activity levels, and selective examinations with SEM and metallography characterized the surface condition of the exceptional specimens. The effectiveness of the surface treatments was gauged by fitting simple parabolae to the activity build-up data and comparing the coefficients with those obtained from untreated control specimens. 10 refs., 23 figs., 4 tabs.

  8. Spent Sealed Sources Management in Switzerland - 12011

    SciTech Connect

    Beer, H.F.

    2012-07-01

    Information is provided about the international recommendations for the safe management of disused and spent sealed radioactive sources wherein the return to the supplier or manufacturer is encouraged for large radioactive sources. The legal situation in Switzerland is described mentioning the demand of minimization of radioactive waste as well as the situation with respect to the interim storage facility at the Paul Scherrer Institute (PSI). Based on this information and on the market situation with a shortage of some medical radionuclides the management of spent sealed sources is provided. The sources are sorted according to their activity in relation to the nuclide-specific A2-value and either recycled as in the case of high active sources or conditioned as in the case for sources with lower activity. The results are presented as comparison between recycled and conditioned activity for three selected nuclides, i.e. Cs-137, Co-60 and Am-241. (author)

  9. The direct measurement of dose enhancement in gamma test facilities

    SciTech Connect

    Burke, E.A.; Snowden, D.P. ); Cappelli, J.R.; Mittleman, S. ); Lowe, L.F.

    1989-12-01

    The design and use of a dual cavity ionization chamber for routine measurement of dose enhancement factors in Co-60 gamma test facilities is described. The enhancement factors can be derived directly from the chamber measurements without recourse to reference data that may be difficult to obtain. It is shown, in agreement with earlier work, that the maximum dose enhancement factors can be altered by a factor two as a result of Compton scatter from relatively small amounts of low or high atomic number materials next to the target. The dual chamber permits the ready detection of such effects. This relatively simple device reliably reproduced earlier results obtained by more involved equipment and procedures. Measured enhancement factors are reported for new material combinations not previously examined and compared with recent calculations.

  10. Synthesis of silver nanoparticles deposited on silica by γ-irradiation and preparation of PE/Ag nano compound masterbatches

    NASA Astrophysics Data System (ADS)

    Nguyen, Thi Kim Lan; Trinh Nguyen, Thuy Ai; Phu Dang, Van; Duy Nguyen, Ngoc; Le, Anh Quoc; Hien Nguyen, Quoc

    2013-12-01

    Silver nanoparticles (AgNPs) deposited on silica were synthesized by gamma Co-60 irradiation of Ag+ dispersion in silica/ethanol/water mixture (9/80/20:w/v/v). The reduction of Ag+ is occurred by hydrated electron (e-aq) and hydrogen atom (H•) generated during radiolysis of ethanol/water. The conversion doses (Ag+ → Ag0) were determined by UV-Vis spectroscopy. The synthesized AgNPs/silica were characterized by transmission electron microscopy (TEM) and x-ray diffraction (XRD), which showed the size of AgNPs to be in the range of 5-40 nm for Ag+ concentrations from 5 to 20 mM. Masterbatches of PE/AgNPs/silica compound with silver content from 250 to 1000 mg kg-1 were also prepared. These masterbatches can be suitably used for various applications such as antimicrobial food containers and packing films, etc.

  11. The radioracemization of isovaline - Cosmochemical implications. [gamma ray effects on Murchison meteorite primordial composition

    NASA Technical Reports Server (NTRS)

    Bonner, W. A.; Blair, N. E.; Lemmon, R. M.; Flores, J. J.; Pollock, G. E.

    1979-01-01

    The optically pure D- and L-enantiomers of isovaline, which cannot be racemized by ordinary chemical mechanisms involving alpha-hydrogen removal and which has been isolated in apparently racemic form from the Murchison meteorite, have been subjected to partial radiolysis by the ionizing radiation from a 3000-Ci Co-60 gamma-ray source. Both in the anhydrous and hydrated solid states and as solid sodium or hydrochloride salts each enantiomer suffered significant radioracemization of the undestroyed residue during its partial radiolysis. The sodium salt of isovaline in 0.1-M aqueous solution suffered extensive radiolysis with relatively small radiation doses, but showed no detectable radioracemization. The significance of these observations with respect to the primordial enantiomeric composition of the isovaline (and other amino acids) indigenous to meteorites is discussed.

  12. Cosmogenic neutron-capture-produced nuclides in stony meteorites

    NASA Technical Reports Server (NTRS)

    Spergel, M. S.; Reedy, R. C.; Lazareth, O. W.; Levy, P. W.; Slatest, L. A.

    1986-01-01

    The complete neutron-flux results and production rates for Cl-36, Ni-59, and Co-60 in stony meteorites of various radii and composition are presented. The relative neutron source strengths and neutron production-versus-depth profiles were determined by using calculated H-3 production rates. The absolute source strengths were normalized to that determined for the moon by Woolum et al. (1975). The energy spectrum of the source neutrons and the neutron transport calculations, which employed the ANISN computer code, were similar to those used for the moon by Lingenfelter et al. (1972). The production rates of the three radionuclides were determined as a function of depth in various spherical meteoroids from the calculated equilibrium neutron-flux distributions and from energy-dependent neutron-capture cross sections. Rates for producing these radionuclides by spallation reactions were also calculated.

  13. RADIATION EFFECTS IN PHYSICAL AGING OF BINARY As-S AND As-Se GLASSES

    SciTech Connect

    Golovchak, Roman; Shpotyuk, O.; Kozdras, A.; Riley, Brian J.; Sundaram, S. K.; McCloy, John S.

    2011-01-24

    Radiation-induced physical aging effects are studied in binary AsxS100-x and AsxSe100-x (30 ≤ x ≤ 42) glasses by conventional differential scanning calorimetry (DSC) method. It is shown that γ-irradiation (Co60 source, ~ 3 MGy dose) of glassy AsxS100-x caused a measurable increase in glass transition temperature and endothermic peak area in the vicinity of glass transition region, which was associated with acceleration of structural relaxation processes in these materials. In contrast to sulfide glasses, the samples of As-Se family did not exhibit any significant changes in DSC curves after γ-irradiation. The observed difference in radiation-induced physical aging between sulfides and selenides was explained by more effective destruction-polymerization transformations and possible metastable defects formation in S-based glassy network.

  14. The characteristic assessment of spent ion exchange resin from PUSPATI TRIGA REACTOR (RTP) for immobilization process

    NASA Astrophysics Data System (ADS)

    Wahida, Nurul; Yasir, Muhamad Samudi; Majid, Amran Ab; Wahab, Mohd Abd; Marzukee, Nik; Paulus, Wilfred; Phillip, Esther; Thanaletchumy, Irwan, M. N.

    2014-09-01

    In this paper, spent ion exchange resin generated from PUSPATI TRIGA reactor (RTP) in Malaysian Nuclear Agency were characterized based on the water content, radionuclide content and radionuclide leachability. The result revealed that the water content in the spent resin is 48%. Gamma spectrometry analysis indicated the presence of 134Cs, 137Cs, 152Eu, 54Mn, 58Co, 60Co and 65Zn. The leachability test shows a small concentrations (<1 Bq/l) of 152Eu and 134Cs were leached out from the spent resin while 60Co activity concentrations slightly exceeded the limit generally used for industrial wastewater i.e. 1 Bq/l. Characterization of spent ion exchange resin sampled from RTP show that this characterization is important as a basis to immobilize this radioactive waste using geopolymer technology.

  15. Measurement of radiation exposure of astronauts by radiochemical techniques

    NASA Technical Reports Server (NTRS)

    Brodzinski, R. L.

    1973-01-01

    A cosmic radiation dose to the Apollo 16 crew of 180 + or - 100 mR was calculated from the specific activities of Na-22 and Na-24 in pre and postflight urine specimens. The specific activities of Cr-51 and Co-60 are higher in postflight specimens than in preflight specimens, presumably due to a postflight injection of radiochromium. The Fe-59 and Cs-137 specific activities are also reported and appear to be normal. The radiation doses received by a pilot and a navigator flying a high altitude mission during the solar flare of August 4 to 9, 1972 were calculated from the specific activity of Na-24 in their urine. These values are compared with the expected radiation dose calculated form the known shape and intensity of the proton spectrum. They demonstrate the magnitude of atmospheric shielding.

  16. Evaluation of the sensitivity of the gas-discharge gamma-counters to the concomitant neutron radiation

    NASA Astrophysics Data System (ADS)

    Pikalov, G. L.; Kiseev, S. V.

    2015-11-01

    In the fields of gamma-neutron radiation the accuracy measurement of gamma- ray doses depends on their sensitivity to concomitant neutron radiation. In this connection, verification results of gamma-dosimetry on the installation with isotope cobalt or cesium sources are not always adequate to measurement results in real gamma-neutron fields. The data prove, that the sensitivity coefficients of gas-discharge gamma-dosimeters at PRIZ-M reactor is 1.23 larger as compared to Co60 source, due to the effect of the concomitant neutrons on their indications. The error due to the neutrons effect can be significantly reduced or eliminated completely, if gamma-dosimeters calibrated in the field of gamma-neutron radiation, adequate spectral and dose characteristics to radiation fields in which they are used.

  17. A third generation mobile high energy radiography system

    SciTech Connect

    Fry, D.A.; Valdez, J.E.; Johnson, C.S.; Kimerly, H.J.; Vananne, J.R.

    1997-12-01

    A third generation mobile high energy radiographic capability has been completed and put into service by the Los Alamos National Laboratory. The system includes a 6 MeV linac x-ray generator, Co-60 gamma source, all-terrain transportation, on-board power, real-time radiography (RTR), a control center, and a complete darkroom capability. The latest version includes upgraded and enhanced portability, flexibility, all-terrain operation, all-weather operation, and ease of use features learned from experience with the first and second generation systems. All systems were required to have the following characteristics; all-terrain, all-weather operation, self-powered, USAF airlift compatible, reliable, simple to setup, easy to operate, and all components two-person portable. The systems have met these characteristics to differing degrees, as is discussed in the following section, with the latest system being the most capable.

  18. Modeling of gamma-radiation impact on transmission characteristics of optical glasses

    NASA Astrophysics Data System (ADS)

    Gusarov, Andrei I.; Doyle, Dominic B.

    2002-01-01

    Optical systems operating in space must maintain their performance over long mission times. Glasses are well known to darken upon exposure to radiation, due to formation of color centers, resulting in performance degradation. Despite increasing demand, an approach which would allow accurate prediction of the end-of-life performance characteristics of space optical instruments, has not been elaborated yet. We propose here a phenomenological methodology that should help to solve the problem. In our model, functional dependencies describing defect generation and annealing are derived from mathematical models, taking into account dose levels and irradiation times relevant for space missions. Numerical values for the parameters come from experimental data. Our experimental methodology is also described. We apply this model to analyze the results obtained for BK7 glass subject to Co60 gamma-radiation.

  19. Radiation sterilization of traditional medicine drugs in Vietnam

    NASA Astrophysics Data System (ADS)

    Hang, N. D.; Canh, T. T.; Thuy, T. T.

    1995-02-01

    With the application of Gamma Co-60 radiation sterilization in pharmaceutical industry, attention should be paid to the possibilities of sterilizing traditional medicine drugs produced in Vietnam. In this paper the opinion which traditional medicine drugs can be satisfactorily sterilized by irradiation is based on the changes of physical and chemical properties of the products and microbiological examinations. The sterilizing radiation dose were calculated and the results are the following (in Mrad) Rheumatine-2.2, Hasinh-3.3, snake extract-1.8, Samcotgiao-2.2. The changes of physical and chemical properties of the products and their toxicity after irradiation have been shown to be not over the levels of allowance.

  20. Radionuclide and electric accelerator sources for food irradiation

    NASA Astrophysics Data System (ADS)

    Lagunas-Solar, Manuel C.; Matthews, Stephen M.

    Radiation processing of food requires radiation sources with high intensity, penetrability, reliability, and the flexibility to be adapted to current food processing techniques. Current proposed regulations limit the radiation sources which can be utilized to radionuclides (i.e. 5.27-y Co-60; or 30.2-y Cs-137) or electrically-driven accelerators (i.e. X rays up to 5 MeV, electron beams up to 10 MeV). Therefore, the power; throughput; and use efficiency of these sources are important factors affecting the design; installation; operation; and economics of large-scale food-processing facilities. An analysis of the advantages and disadvantages of these sources is presented here, with special attention to the current status of both technologies, and with emphasis on the needs of the food-processing industry.