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Sample records for co-60 sobre vyns

  1. Co-60 in lunar samples.

    NASA Technical Reports Server (NTRS)

    Wahlen, M.; Finkel, R. C.; Imamura, M.; Kohl, C. P.; Arnold, J. R.

    1973-01-01

    Results obtained for Co-60 in lunar soils and rocks of different depths are discussed. These results are compared to a production calculation based on the work of Lingenfelter et al. (1972). The measurement of Co-60 activities can give information about the present-day equilibrium neutron flux in the lunar regolith. The most important quantity which can be derived from these data is the absolute present-day lunar neutron production rate.

  2. 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.

  3. 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.

  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. 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.

  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. Origin of the planar Hall effect in nanocrystalline Co60Fe20B20.

    PubMed

    Seemann, K M; Freimuth, F; Zhang, H; Blügel, S; Mokrousov, Y; Bürgler, D E; Schneider, C M

    2011-08-19

    An angle dependent analysis of the planar Hall effect (PHE) in nanocrystalline single-domain Co(60)Fe(20)B(20) thin films is reported. In a combined experimental and theoretical study we show that the transverse resistivity of the PHE is entirely driven by anisotropic magnetoresistance (AMR). Our results for Co(60)Fe(20)B(20) obtained from first principles theory in conjunction with a Boltzmann transport model take into account the nanocrystallinity and the presence of 20 at. % boron. The ab initio AMR ratio of 0.12% agrees well with the experimental value of 0.22%. Furthermore, we experimentally demonstrate that the anomalous Hall effect contributes negligibly in the present case.

  8. 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.

  9. Increases in morphologically abnormal sperm in rats exposed to Co60 irradiation.

    PubMed

    Lock, L F; Soares, E R

    1980-01-01

    We have investigated the effects of testicular exposure to different doses of Co60 radiation on sperm morphology in F-344 rats. The results indicate that from 150 rad to 500 rad gamma irradiation causes statistically significant, dose-related increased in 1) the percent of morphologically aberrant sperm and 2) the frequency of tailless sperm. Both of these effects were detectable in sperm which were derived from treated spermatid, spermatocytes, and spermatogonial cells. These data indicate that the development of a sperm morphology assay in rats is feasible.

  10. 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

  11. Effect of Co-60 single escape peak on detection of Cs-137 in analysis of radionuclide from research reactor

    SciTech Connect

    Kim, M. S.; Park, S. J.

    2006-07-01

    The effect of the single escape peak of 1173 keV gamma-rays from Co-60 on the detection of Cs-137 activity is analyzed. The single escape peak of 1173 keV gamma-rays from Co-60 is located at the 662 keV, which is very close to the energy of gamma-rays from Cs-137. This single escape peak may be mistaken for the gamma-ray peak from Cs-137 activity in the case of large area of 1173 keV peak. The detection of Cs-137 is very important to the judgment of the contamination or the leakage of the material containing the fission product like reactor pool water and in the several experiments for reactor physics such as burn-up estimation. In this work, the areas of the single escape peak of the 1173 keV gamma-rays from Co-60 are measured with several full energy peak areas by using the HPGe detector. The critical limit by which we can decide whether the net count of 662 keV peak due to Co-60 would be significant or not is deduced. For this detection system, when the area of full energy peak is larger than 4.5 million, the single escape peak of 1173 keV gamma-rays from Co-60 can be regarded as the single significant peak. Therefore, it is confirmed that the detection of the Cs-137 activity is affected by the Co-60 in this case. Conservatively, for this detection system, it is recommended that the area of 1173 keV peak of Co-60 would be less than 2 million for neglecting the effect of Co-60. (authors)

  12. Dosimetric Consistency of Co-60 Teletherapy Unit- a ten years Study

    PubMed Central

    Baba, Misba H; Mohib-ul-Haq, M.; Khan, Aijaz A.

    2013-01-01

    Objective The goal of the Radiation standards and Dosimetry is to ensure that the output of the Teletherapy Unit is within ±2% of the stated one and the output of the treatment dose calculation methods are within ±5%. In the present paper, we studied the dosimetry of Cobalt-60 (Co-60) Teletherapy unit at Sher-I-Kashmir Institute of Medical Sciences (SKIMS) for last 10 years. Radioactivity is the phenomenon of disintegration of unstable nuclides called radionuclides. Among these radionuclides, Cobalt-60, incorporated in Telecobalt Unit, is commonly used in therapeutic treatment of cancer. Cobalt-60 being unstable decays continuously into Ni-60 with half life of 5.27 years thereby resulting in the decrease in its activity, hence dose rate (output). It is, therefore, mandatory to measure the dose rate of the Cobalt-60 source regularly so that the patient receives the same dose every time as prescribed by the radiation oncologist. The under dosage may lead to unsatisfactory treatment of cancer and over dosage may cause radiation hazards. Our study emphasizes the consistency between actual output and output obtained using decay method. Methodology The methodology involved in the present study is the calculations of actual dose rate of Co-60 Teletherapy Unit by two techniques i.e. Source to Surface Distance (SSD) and Source to Axis Distance (SAD), used for the External Beam Radiotherapy, of various cancers, using the standard methods. Thereby, a year wise comparison has been made between average actual dosimetric output (dose rate) and the average expected output values (obtained by using decay method for Co-60.) Results The present study shows that there is a consistency in the average output (dose rate) obtained by the actual dosimetry values and the expected output values obtained using decay method. The values obtained by actual dosimetry are within ±2% of the expected values. Conclusion The results thus obtained in a year wise comparison of average output by

  13. Electric field effect on the magnetization process for a very thin Co60Fe40 film

    NASA Astrophysics Data System (ADS)

    Suzuki, K. Z.; Ranjbar, R.; Sugihara, A.; Kondo, Y.; Mizukami, S.

    2016-08-01

    The electric field effect on the magnetization process for a very thin Co60Fe40 film was studied. The magnetization process under the electric field was characterized using tunnel magnetoresistance curves measured in a fully-epitaxial (001)-oriented CoFe(1)/MgO/CoFe(3) (thickness in nanometers) magnetic tunnel junction, where both the CoFe electrodes are magnetized in- plane. The out-of-plane saturation field of the thinner CoFe electrode changed linearly by varying the applied voltage, and the field-induced change of saturation field was estimated to be -0.10 TV-1. This change in the saturation field is interpreted as the electric field induced change in a perpendicular magnetic anisotropy originating from the CoFe/MgO interface. The electric field effect efficiency was estimated to be about 200 fJV-1 m-1.

  14. 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.

  15. Temperature evolution of magnetic properties for (Cu/Co)60/Fe multilayer

    NASA Astrophysics Data System (ADS)

    Yalçın, O.; Ünlüer, Ş.; Kazan, S.; Özdemir, M.; Öner, Y.

    2015-01-01

    In order to investigate the magnetic properties by ferromagnetic resonance (FMR) techniques, (Cu/Co)60/Fe multilayer on Si(001) substrate has been prepared by conventional sputtering. Evolution of the FMR spectra with temperature, resonance field, and magnetization curve has been calculated using the Landau-Lifshitz equation of motion for magnetization with the Bloch-Bloembergen type damping term. An almost linear evolution of frequency of resonance field has been shown for x-, k- and q-band spectra. By the analysis of the resonance field-frequency relation, the effect of the internal field is refined and thus the spectroscopic g-value and internal field were calculated. The magnetostatic signal originated from the magnetostatic anisotropy energy has been determined to be opposed by the decreasing exchange and dipolar energies.

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

    SciTech Connect

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

    2016-03-11

    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.

  17. Computerized triplet beam orientation optimization for MRI-guided Co-60 radiotherapy.

    PubMed

    Nguyen, Dan; Thomas, David; Cao, Minsong; O'Connor, Daniel; Lamb, James; Sheng, Ke

    2016-10-01

    Magnetic resonance imaging (MRI)-guided Co-60 provides daily and intrafractional MRI soft tissue imaging for improved target and critical organ tracking. To increase delivery efficiency, the system uses three Co-60 sources at 120° apart, allowing up to 600 cGy combined dose rate at isocenter. Despite the potential tripling in output, creating a delivery plan that uses all three sources is considerably unintuitive. Here, the authors computerize the triplet orientation optimization using column generation, an approach that was demonstrated effective in integrated beam orientation and fluence optimization for noncoplanar therapies. To achieve a better plan quality without increasing the treatment time, the authors then solve a fluence map optimization (FMO) problem while regularizing the fluence maps to reduce the number of deliverable MLC segments. Three patients-one prostate, one lung, and one head and neck boost plan (H&NBoost)-were evaluated in this study. For each patient, the beamlet doses were calculated using Monte Carlo, under a 0.35 T magnetic field, for 180 equally spaced coplanar beams grouped into 60 triplets. The beamlet size is 1.05 × 0.5 cm determined by the MLC leaf thickness and step size. The triplets were selected using the column generation algorithm. The FMO problem was formulated using an L2-norm dose fidelity term and an L1-norm anisotropic total variation regularization term, which allows controlling the number of MLC segments, and hence the treatment time, with minimal degradation to the dose. The authors' Fluence Regularization and Optimized Selection of Triplets (FROST) plans were compared against the clinical treatment plans (CLNs) produced by an experienced dosimetrist. PTV homogeneity, max dose, mean dose, D95, D98, and D99 were evaluated. OAR max and mean doses, as well as R50, defined as the ratio of the 50% isodose volume over the planning target volume were investigated. The mean PTV D95, D98, and D99 differ by +0.04%, +0.07%, and

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

    SciTech Connect

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

    2016-01-22

    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) B{sub 2}O{sub 3} − 20 CaO – 10 MgO-(y) Dy{sub 2}O{sub 3} 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 Dy{sub 2}O{sub 3} concentration of 0.5 mol % were determined for thermoluminescence dosimeter (TLD) reader used.

  19. Cardiovascular Changes in Atherosclerotic ApoE-Deficient Mice Exposed to Co60 (γ) Radiation

    PubMed Central

    Kumarathasan, Prem; Vincent, Renaud; Blais, Erica; Saravanamuthu, Anu; Gupta, Pallavi; Wyatt, Heather; Mitchel, Ronald; Hannan, Mohammed; Trivedi, Akilesh; Whitman, Stewart

    2013-01-01

    Background There is evidence for a role of ionizing radiation in cardiovascular diseases. The goal of this work was to identify changes in oxidative and nitrative stress pathways and the status of the endothelinergic system during progression of atherosclerosis in ApoE-deficient mice after single and repeated exposure to ionizing radiation. Methods and Results B6.129P2-ApoE tmlUnc mice on a low-fat diet were acutely exposed (whole body) to Co60 (γ) (single dose 0, 0.5, and 2 Gy) at a dose rate of 36.32 cGy/min, or repeatedly (cumulative dose 0 and 2 Gy) at a dose-rate of 0.1 cGy/min for 5 d/wk, over a period of 4 weeks. Biological endpoints were investigated after 3–6 months of recovery post-radiation. The nitrative stress marker 3-nitrotyrosine and the vasoregulator peptides endothelin-1 and endothelin-3 in plasma were increased (p<0.05) in a dose-dependent manner 3–6 months after acute or chronic exposure to radiation. The oxidative stress marker 8-isoprostane was not affected by radiation, while plasma 8-hydroxydeoxyguanosine and L-3,4-dihydroxyphenylalanine decreased (p<0.05) after treatment. At 2Gy radiation dose, serum cholesterol was increased (p = 0.008) relative to controls. Percent lesion area increased (p = 0.005) with age of animal, but not with radiation treatment. Conclusions Our observations are consistent with persistent nitrative stress and activation of the endothelinergic system in ApoE−/− mice after low-level ionizing radiation exposures. These mechanisms are known factors in the progression of atherosclerosis and other cardiovascular diseases. PMID:23840332

  20. 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.

  1. 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.

  2. Quality of tri-Co-60 MR-IGRT treatment plans in comparison with VMAT treatment plans for spine SABR.

    PubMed

    Choi, Chang Heon; Park, So-Yeon; Kim, Jung-In; Kim, Jin Ho; Kim, Kyubo; Carlson, Joel; Park, Jong Min

    2017-02-01

    To investigate the plan quality of tri-Co-60 intensity-modulated radiation therapy (IMRT) plans for spine stereotactic ablative radiotherapy (SABR). A total of 20 patients with spine metastasis were retrospectively selected. For each patient, a tri-Co-60 IMRT plan and a volumetric-modulated arc therapy (VMAT) plan were generated. The spinal cords were defined based on MR images for the tri-Co-60 IMRT, while isotropic 1-mm margins were added to the spinal cords for the VMAT plans. The VMAT plans were generated with 10-MV flattening filter-free photon beams of TrueBeam STx(™) (Varian Medical Systems, Palo Alto, CA), while the tri-Co-60 IMRT plans were generated with the ViewRay(™) system (ViewRay inc., Cleveland, OH). The initial prescription dose was 18 Gy (1 fraction). If the tolerance dose of the spinal cord was not met, the prescription dose was reduced until the spinal cord tolerance dose was satisfied. The mean dose to the target volumes, conformity index and homogeneity index of the VMAT and tri-Co-60 IMRT were 17.8 ± 0.8 vs 13.7 ± 3.9 Gy, 0.85 ± 0.20 vs 1.58 ± 1.29 and 0.09 ± 0.04 vs 0.24 ± 0.19, respectively. The integral doses and beam-on times were 16,570 ± 1768 vs 22,087 ± 2.986 Gy cm(3) and 3.95 ± 1.13 vs 48.82 ± 10.44 min, respectively. The tri-Co-60 IMRT seems inappropriate for spine SABR compared with VMAT. Advances in knowledge: For spine SABR, the tri-Co-60 IMRT is inappropriate owing to the large penumbra, large leaf width and low dose rate of the ViewRay system.

  3. Capacitance-Based Dosimetry of Co-60 Radiation using Fully-Depleted Silicon-on-Insulator Devices

    PubMed Central

    Li, Yulong; Porter, Warren M.; Ma, Rui; Reynolds, Margaret A.; Gerbi, Bruce J.; Koester, Steven J.

    2015-01-01

    The capacitance based sensing of fully-depleted silicon-on-insulator (FDSOI) variable capacitors for Co-60 gamma radiation is investigated. Linear response of the capacitance is observed for radiation dose up to 64 Gy, while the percent capacitance change per unit dose is as high as 0.24 %/Gy. An analytical model is developed to study the operational principles of the varactors and the maximum sensitivity as a function of frequency is determined. The results show that FDSOI varactor dosimeters have potential for extremely-high sensitivity as well as the potential for high frequency operation in applications such as wireless radiation sensing. PMID:27840451

  4. 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

  5. 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

    2014-04-21

    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%.

  6. Liver dysfunction following whole-body Co-60 irradiation in gerbil (Meriones Hurrianae Jerdon) and house rat (Rattus rattus Rufescens).

    PubMed

    Dixit, V P; Agrawal, M; Gupta, C H

    1976-08-01

    Liver dysfunction following whole-body Co-60 irradiation has been studied in domestic and desert rat species. A significant elevation in the serum transaminases activity was noticed both in gerbil and house rat. Alkaline phosphatase and plasma cholesterol levels were also increased indicating an early radiation impairment of the liver tissue, which was later confirmed by histological studies. A steady fall in liver glycogen in irradiated gerbils was strikingly in contrast to an increase in irradiated house rat. Drastic depletion in liver glycogen, changes in the serum enzyme levels and the severity of the hepatic necrosis in gerbils point out that desert mammalian species are much more sensitive to radiation hazard as compared with domestic ones.

  7. 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

  8. A comprehensive study on HDR brachytherapy treatments of cervical cancers: using the first Co-60 BEBIG Multisource Unit in Bangladesh.

    PubMed

    Malik, Sadiq R; Banu, Parvin A; Rukhsana, Naheed

    2011-06-01

    The report presents an extraordinary synthesis of customer acceptance procedures (CAP), quality assurance tests (QA) in the treatment of cervical cancer patients, using the first Co-60 Multisource Unit(®) in Bangladesh. The QA and commissioning required measurements and emergency tests verifying the functional limits of parameters acceptable for the new HDR afterloader. Acceptable limits were: 1) the deviation between specified and measured source strength: ± 3%; 2) the positional accuracy and uniformity: ± 1 mm; 3) the temporal accuracy (i.e. timer error and linearity and end error): ± 1% or 30 sec.; 4) treatment planning system (digitizer and localization software): ± 3% or 1 mm; 5) the distance from line to first dwell position and all the others: 5 mm and 10 mm (± 1 mm). Till February 2011, 47 patients were treated with HDR with more than 140 insertions applied. Amongst them, 12 patients were in stage IIB and IIIB, 22 were postoperative (IA and IB) while the remaining 13 patients were with unknown stage. All the cases with stage IIB and IIIB received concurrent chemo-radiation and brachytherapy. Postoperative patients received EBRT (50 Gy and HDR) according to the institutional protocol. CT scans were completed before HDR-plus planning with a good reproducibility (± 2%) and were documented in repeating the plan for the same set up of a patient. Absorbed dose (Gy) to a point P, at a distance of "r" in centimeters from a source of the Reference Air Kerma Rate (RAKR) has been utilized for the QA of the source, where source strength measurement was accomplished. All methods and analysis applicable to the QA and commissioning of Co-60 have been investigated and systematically analyzed, measured and documented before the treatment of a patient. Studies and safety requirements of this HDR remote afterloader were carried out. Acceptance and the QA were imperative to justify functionality and dependability in delivering the treatment. Implications of these

  9. Molecular level analyses of mechanical properties of PTFE sterilized by Co-60 γ-ray irradiation for clinical use

    NASA Astrophysics Data System (ADS)

    Furuta, Masakazu; Matsugaki, Aira; Nakano, Takayoshi; Hirata, Isao; Kato, Koichi; Oda, Takashi; Sato, Mamoru; Okazaki, Masayuki

    2017-10-01

    Recently, Co-60 gamma-ray irradiation has become markedly popular for the sterilization of biomedical materials, including expanded PTFE. However, its effect on the properties of PTFE has not been thoroughly examined. In this study, changes in the properties of PTFE before and after irradiation were analyzed physicochemically and discussed crystallographically. The tensile breaking strengths of PTFE decreased markedly on irradiation at 1 kGy, and were maintained at almost one fourth of the original value (44.3±2.5 N/mm2) ranging from 5 to 100 kGy. XPS analysis indicated that the atomic concentrations of carbon (C) and fluorine (F) of PTFE were not different among samples irradiated at various dosages. Raman spectra of PTFE showed a slight increase of the absorption peak intensity at 735 cm-1 in an irradiation dosage-dependent manner. X-ray diffraction showed that the crystal size of PTFE (56.7±1.0 nm) became smaller after radiation at 100 kGy (48.5±0.6 nm). These results are consistent with the above results of Raman analysis. It is suggested that the observed changes in the mechanical properties of PTFE may be due to nano-scale C-C bond scission by gamma ray irradiation, and not due to the formation of micro-scale cracks.

  10. A comparison of treatment plan quality between Tri-Co-60 intensity modulated radiation therapy and volumetric modulated arc therapy for cervical cancer.

    PubMed

    Park, Jong Min; Park, So-Yeon; Kim, Jung-In; Kang, Hyun-Cheol; Choi, Chang Heon

    2017-08-01

    To investigate the plan quality of tri-Co-60 intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) for cervical cancer. A total of 20 patients who received postoperative radiotherapy for cervical cancer were selected. For each patient, a tri-Co-60 IMRT plan for which the target volume was the planning target volume (PTV) generated by adding 1mm isotropic margins from the clinical target volume (CTV) and a VMAT plan for which the target volume was the PTV generated by adding 7mm and 10mm margins from the CTV were generated. The tri-Co-60 IMRT plans were generated with the ViewRay™ system while the VMAT plans were generated with 15-MV photon beams from a linear accelerator (prescription dose=50.4Gy in 28 fractions). The average volumes of the PTVs and CTVs were 704.9cc±87.8cc and 271.6cc±51.6cc, respectively. No noticeable differences in the dose-volumetric parameters for the target volumes were observed between the tri-Co-60 IMRT and VMAT plans. The values of V40Gy for the small bowel and rectal wall, V45Gy of the bladder, and V35Gy of the femoral heads for the VMAT plans were 14.6%±7.8%, 54.4%±4.2%, 30.0%±4.7%, and 8.9%±3.3%, respectively. Those of the tri-Co-60 IMRT plans were 2.8%±2.1%, 23.0%±8.9%, 17.1%±6.1%, and 0.3%±0.4%, respectively. Owing to the target margin reduction capability, the tri-Co-60 IMRT plans were more favorable than the VMAT plans for cervical cancer. Copyright © 2017. Published by Elsevier Ltd.

  11. SU-E-T-156: Can Sr-90 Check Sources Replace Co-60 Measurements for Monitoring of Reference Chamber Stability?

    SciTech Connect

    McEwen, M; Niven, D; Miksys, N

    2015-06-15

    Purpose: To determine the ultimate precision of a system for monitoring reference-class ion chamber stability using a commercial Sr-90 check source. Methods: A detailed investigation of a commercial Sr-90 check source (PTW48002) was carried out using a series of Farmer-type ionization chambers. Investigations included: positioning repeatability (angular variation as chamber is rotated in source, variation in ionization current with vertical alignment); chamber settling; short and long term repeatability Results: i) Measurement precision – the ionization current was typically 10 pA, and therefore a high-precision electrometer is required to prevent electrometer noise/resolution/leakage biaising the results. ii) Chamber settling - the chamber response stabilizes after approximately 10 minutes, which is longer than reported for linac beams and is likely due to the low doserate of the source.iii) The measured response depended at the 1 % level on the orientation of the chamber with respect to the source. However, consistent positioning resulted in repeatability at the 0.05 % level. Care was also required to ensure that the chamber was consistently positioned vertically with respect to the source. The sensitivity to vertical position was found to be > 1 % per mm.iv)With a uniform procedure the long-term (> 6 month) repeatability was found to be better than 0.1 % for multiple chamber types and potentially a precision of 0.05 % is achievable. Conclusion: A Sr-90 check source is easy to use and is a viable alternative to Co-60 for monitoring reference chamber stability.

  12. Treatment planning study of the 3D dosimetric differences between Co-60 and Ir-192 sources in high dose rate (HDR) brachytherapy for cervix cancer

    PubMed Central

    Hayman, Orla; Muscat, Sarah

    2012-01-01

    Purpose To evaluate whether Co-60 is equivalent to Ir-192 for HDR cervical brachytherapy, through 3D-DVH dose comparisons in standard and optimised plans. Previous studies have only considered 2D dosimetry, point dose comparisons or identical loading. Typical treatment times and economics are considered. Material and methods Plans were produced for eight cervix patients using Co-60 and Ir-192 sources, CT imaging and IU/two-channel-ring applicator (Eckert Ziegler BEBIG). The comparison was made under two conditions: (A) identical dwell positions and loading, prescribed to Point A and (B) optimised source dwells, prescribed to HR-CTV. This provided a direct comparison of inherent differences and residual differences under typical clinical plan optimisation. The DVH (target and OAR), ICRU reference points and isodose distributions were compared. Typical treatment times and source replacement costs were compared. Results Small differences (p < 0.01) in 3D dosimetry exist when using Co-60 compared to Ir-192, prescribed to Point A with identical loading patterns, particularly 3.3% increase in rectum D2cc. No significant difference was observed in this parameter when prescribing to the HR-CTV using dwell-time optimisation. There was no statistically significant difference in D90 between the two isotopes. Co-60 plans delivered consistently higher V150% (mean +4.4%, p = 0.03) and V400% (mean +11.6%, p < 0.01) compared to Ir-192 in optimised plans. Differences in physical source properties were overwhelmed by geometric effects. Conclusions Co-60 may be used as an effective alternative to Ir-192 for HDR cervix brachytherapy, producing similar plans of equivalent D90, but with logistical benefits. There is a small dose increase along the extension of the source axis when using Co-60 compared to Ir-192, leading to small rectal dose increases for identical loading patterns. This can be eliminated by planning optimisation techniques. Such optimisation may also be associated with

  13. Effects of immobilization beds on the dose in the entrance and exit dose region for Co-60, 4, 6 and 15 MV photons.

    PubMed

    Bilge, H; Yondem, S; Kucucuk, H; Cakir, A; Meral, R

    2008-01-01

    The aim of this study was to determine the effects of Styrofoam beds used for immobilization on build-up and exit dose regions for high energy photon beams. Build-up dose and exit dose measurements in central axis of Co-60 and 4, 6 and 15 MV photons at various field sizes and source to phantom distances were made in a water equivalent solid phantom with 2, 5 and 10 cm thick uniform Styrofoam beds at the surface. A Markus type plane-parallel ion chamber with fixed separation between collecting electrodes was used to measure the percent depth doses. The surface dose increased almost linearly with field size for Co-60, 4, 6 and 15 MV X-ray beams. The effect of immobilization (Styrofoam beds) on the surface dose increased with the thickness and this effect was lower with higher energies. When a 2 cm thick Styrofoam bed was used for immobilization, the surface dose in a 10x10 cm field was higher (43.9, 36.8, 28.8 and 14.9% for Co-60, 4, 6 and 15 MV, respectively). As the Styrofoam bed was thicker, the maximum dose point moved closer to the surface of the phantom for all energies. The exit surface dose was also enhanced with the presence of Styrofoam beds and similar to the effects on the surface dose. This enhancement was the maximum 5% for high energy photon beams and 6% for Co-60 beam. The introduction of Styrofoam beds in the radiation beam for the immobilization of the patient increases surface and exit doses to a considerable extent.

  14. 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).

  15. Dosimetric analysis of Co-60 source based high dose rate (HDR) brachytherapy: A case series of ten patients with carcinoma of the uterine cervix.

    PubMed

    Gurjar, Om Prakash; Batra, Manika; Bagdare, Priyusha; Kaushik, Sandeep; Tyagi, Atul; Naik, Ayush; Bhandari, Virendra; Gupta, Krishna Lal

    2016-01-01

    To analyse the dosimetric parameters of Co-60 based high dose rate (HDR) brachytherapy plans for patients of carcinoma uterine cervix. Co-60 high dose rate (HDR) brachytherapy unit has been introduced in past few years and is gaining importance owing to its long half life, economical benefits and comparable clinical outcome compared to Ir-192 HDR brachytherapy. A study was conducted on ten patients with locally advanced carcinoma of the uterine cervix (Ca Cx). Computed tomography (CT) images were taken after three channel applicator insertions. The planning for 7 Gray per fraction (7 Gy/#) was done for Co-60 HDR brachytherapy unit following the American Brachytherapy Society (ABS) guidelines. All the patients were treated with 3# with one week interval between fractions. The mean dose to high risk clinical target volumes (HRCTV) for D90 (dose to 90% volume) was found to be 102.05% (Standard Deviation (SD): 3.07). The mean D2cc (dose to 2 cubic centimeter volume) of the bladder, rectum and sigmoid were found to be 15.9 Gy (SD: 0.58), 11.5 Gy (SD: 0.91) and 4.1 Gy (SD: 1.52), respectively. The target coverage and doses to organs at risk (OARs) were achieved as per the ABS guidelines. Hence, it can be concluded that the Co-60 HDR brachytherapy unit is a good choice especially for the centers with a small number of brachytherapy procedures as no frequent source replacement is required like in an Ir-192 HDR unit.

  16. Measurement of activity of spent ionizing sources based on Cs-137 and Co-60 placed in well-type storage facilities

    SciTech Connect

    Diordiy, Mikhail N.; Nikolaev, Oleg A.; Karlina, Olga K.; Semenov, Valeriy E.; Barinova, Ella A.

    2013-07-01

    In this paper the method of activity measurement of spent radionuclide sources (SRS) based on Co-60 and Cs- 137 placed in well-type storage facilities, in order to forecast the SRS activity which can be placed at this facility is described. The distribution of the absorbed dose through the absorption material is measured with the help of the described absorption spectrometer. This information allows determining the activity of individual radionuclides with the help of mathematical methods. (authors)

  17. 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.

  18. Fiber optic Cerenkov radiation sensor system to estimate burn-up of spent fuel: characteristic evaluation of the system using Co-60 source

    NASA Astrophysics Data System (ADS)

    Shin, S. H.; Jang, K. W.; Jeon, D.; Hong, S.; Kim, S. G.; Sim, H. I.; Yoo, W. J.; Park, B. G.; Lee, B.

    2013-09-01

    Cerenkov radiation occurs when charged particles are moving faster than the speed of light in a transparent dielectric medium. In optical fibers, the Cerenkov light also can be generated due to their dielectric components. Accordingly, the radiation-induced light signals can be obtained using optical fibers without any scintillating material. In this study, to measure the intensities of Cerenkov radiation induced by gamma-rays, we have fabricated the fiber-optic Cerenkov radiation sensor system using silica optical fibers, plastic optical fibers, multi-anode photomultiplier tubes, and a scanning system. To characterize the Cerenkov radiation generated in optical fibers, the spectra of Cerenkov radiation generated in the silica and plastic optical fibers were measured. Also, the intensities of Cerenkov radiation induced by gamma-rays generated from a cylindrical Co-60 source with or without lead shielding were measured using the fiberoptic Cerenkov radiation sensor system.

  19. SU-E-T-31: A Fast Finite Size Pencil Beam (FSPB) Convolution Algorithm for a New Co-60 Arc Therapy Machine

    SciTech Connect

    Chibani, O; Eldib, A; Ma, C

    2015-06-15

    Purpose: Present a fast Finite Size Pencil Beam (FSPB) convolution algorithm for a new Co-60 arc therapy machine. The FSPB algorithm accounts for (i) strong angular divergence (short SAD), (ii) heterogeneity effect for primary attenuation, and (iii) source energy spectrum. Methods: The FSPB algorithm is based on a 0.5×0.5-cm2 dose kernel calculated using the GEPTS (Gamma Electron and Positron Transport System) Monte Carlo code. The dose kernel is tabulated using a thin XYZ mesh (0.1 mm steps in lateral directions) for radius less than 1 cm and using an RZ mesh (with varying steps) for larger radial distance. To account for SSD effect, 11 dose kernels with SSDs varying between 30 cm to 80 cm are calculated. Maynord factor and “lateral stretching” are applied to account for differences between closest and actual SSD. Appropriate rotations and second order interpolation are used to calculate the dose from a given beamlet to a point. Results: Accuracy: Dose distributions in water with 80 cm SSD are calculated using the new FSPB convolution algorithm and full Monte Carlo simulation (gold standard). Figs 1–4 show excellent agreements between FSPB and Monte Carlo calculations for different field sizes and at different depths. The dose distribution for a prostate case is calculated using FSPB (Fig.5). Sixty conformal beams with rectum blocking are assumed. Figs 6–8 show the comparison with Monte Carlo simulation based on the same beam apertures. The excellent agreement demonstrates the accuracy of the new algorithm in handling SSD variation, oblique incidence, and scatter contribution.Speed: The FSPB convolution algorithm calculates 28 million dose points per second using a single 2.2-GHz CPU. The present algorithm is seven times faster than a similar algorithm from Gu et al. (Phys. Med. Biol. 54, 2009, 6287–6297). Conclusion: A fast and accurate FSPB convolution algorithm was developed and benchmarked.

  20. 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.

  1. SU-F-303-17: Real Time Dose Calculation of MRI Guided Co-60 Radiotherapy Treatments On Free Breathing Patients, Using a Motion Model and Fast Monte Carlo Dose Calculation

    SciTech Connect

    Thomas, D; O’Connell, D; Lamb, J; Cao, M; Yang, Y; Agazaryan, N; Lee, P; Low, D

    2015-06-15

    Purpose: To demonstrate real-time dose calculation of free-breathing MRI guided Co−60 treatments, using a motion model and Monte-Carlo dose calculation to accurately account for the interplay between irregular breathing motion and an IMRT delivery. Methods: ViewRay Co-60 dose distributions were optimized on ITVs contoured from free-breathing CT images of lung cancer patients. Each treatment plan was separated into 0.25s segments, accounting for the MLC positions and beam angles at each time point. A voxel-specific motion model derived from multiple fast-helical free-breathing CTs and deformable registration was calculated for each patient. 3D images for every 0.25s of a simulated treatment were generated in real time, here using a bellows signal as a surrogate to accurately account for breathing irregularities. Monte-Carlo dose calculation was performed every 0.25s of the treatment, with the number of histories in each calculation scaled to give an overall 1% statistical uncertainty. Each dose calculation was deformed back to the reference image using the motion model and accumulated. The static and real-time dose calculations were compared. Results: Image generation was performed in real time at 4 frames per second (GPU). Monte-Carlo dose calculation was performed at approximately 1frame per second (CPU), giving a total calculation time of approximately 30 minutes per treatment. Results show both cold- and hot-spots in and around the ITV, and increased dose to contralateral lung as the tumor moves in and out of the beam during treatment. Conclusion: An accurate motion model combined with a fast Monte-Carlo dose calculation allows almost real-time dose calculation of a free-breathing treatment. When combined with sagittal 2D-cine-mode MRI during treatment to update the motion model in real time, this will allow the true delivered dose of a treatment to be calculated, providing a useful tool for adaptive planning and assessing the effectiveness of gated treatments.

  2. Update of the BIPM comparison BIPM.RI(II)-K1.Co-60 of activity measurements of the radionuclide 60Co to include the 2011 result of the CNEA (Argentina), the 2012 results of the BARC (India) and the NRC (Canada), and the 2014 result of the NIM (China)

    NASA Astrophysics Data System (ADS)

    Michotte, C.; Ratel, G.; Courte, S.; Arenillas, P.; Balpardo, C.; Joseph, L.; Anuradha, R.; Kulkarni, D. B.; Galea, R.; Moore, K.; Stroak, A.; Zhang, Ming; Liang, Juncheng; Liu, Haoran

    2017-01-01

    Since 2010, four national metrology institutes (NMI) have each submitted a sample of known activity of 60Co to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Co-60. The values of the activity submitted were between about 175 kBq and 1600 kBq. The primary standardization results for the CNEA, Argentina and the BARC, India replace their earlier result of 2003 and 2001, respectively. There are now seventeen results in the BIPM.RI(II)-K1.Co-60 comparison. The key comparison reference value (KCRV) has been updated using the power-moderated weighted mean. The degrees of equivalence between each equivalent activity measured in the SIR and the KCRV have been calculated and the results are given in the form of a table. A graphical presentation is also given. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  3. Geological and physicochemical controls of the spatial distribution of partition coefficients for radionuclides (Sr-90, Cs-137, Co-60, Pu-239,240 and Am-241) at a site of nuclear reactors and radioactive waste disposal (St. Petersburg region, Russian Federation).

    PubMed

    Rumynin, Vyacheslav G; Nikulenkov, Anton M

    2016-10-01

    The paper presents a study of the sorption properties of sediments of different geological ages and lithological types, governing radionuclide retention in the subsurface (up to 160 m beneath the surface) within the area of potential influence of the Northwestern Center of Atomic Energy (NWCAE), St. Petersburg region, RF. The focus of this work is mostly on the sedimentary rocks of two types, i.e., weakly cemented sandstone and lithified clay formations of Cambrian and Vendian series. The first lithological unit is associated with a groundwater reservoir (Lomonosov aquifer), and the second one, with both a relative aquitard in the upper part of the Vendian formation (Kotlin clay) and a regional aquifer (Gdov aquifer) in the lower part of the formation. The main mechanisms responsible for the variability of the sorption distribution coefficient (Kd, defined as the ratio of the concentration of solute on solid phase to its concentration in solution at equilibrium) was identified for radionuclides such as Sr-90, Cs-137, Co-60, Pu-239,240, and Am-241. It was shown that the main factors contributing to the chemical heterogeneity of the Cambrian sandstone were related to the presence of secondary minerals (iron and magnesium oxides and hydroxides produced by the weathering process) in trace amounts, forming correlated layer structures. The statistical analysis of nonlinear isotherms confirmed this conclusion. For the Vendian formation, a determinate trend was established in the Kd change over depth as a result of temporal trends in the sedimentation process and pore-water chemistry. The geostatistical characteristics and the spatial correlation models for describing linear sorption of different radionuclides are not identical, and the exhibition of chemical heterogeneity of sedimentary rock of a particular lithological type depends on radionuclide chemistry. Moreover, variogram analysis for some Kd data sets (both in Cambrian and Vendian formations) demonstrates the

  4. Tolerance of mango cv. ´Ataulfo' to irradiation with Co-60 vs. hydrothermal phytosanitary treatment

    NASA Astrophysics Data System (ADS)

    Gómez-Simuta, Y.; Hernández, Emilio; Aceituno-Medina, Marysol; Liedo, Pablo; Escobar-López, Arseny; Montoya, Pablo; Bravo, Bigail; Hallman, Guy J.; Bustos, M. Emilia; Toledo, Jorge

    2017-10-01

    The use of ionizing irradiation or the use of hot water treatment (HWT) has been demonstrated as a successful commercial phytosanitary treatment during the past two decades. Several countries currently use this technology for commercial treatments to meet plant quarantine requirements. However, hydrothermal treatment has been found to significantly affect the firmness of ;Ataulfo; mango fruit, the susceptibility to damage by cold and it also accelerates their maturation. In this study, we focused on the effect of irradiation doses on the sensorial quality and the physiochemical properties of mango cv ;Ataulfo; compared with the traditional hot water treatment. We found that doses of 150 Gy and 300 Gy of gamma radiation can be applied successfully as well as the hot water treatment. There was no significant difference in between irradiation treatments in terms of weight loss, external and internal color, pH, soluble solids, titratable acidity and firmness, and consumer's acceptance. There was no adverse effect of color appearance, odor and flavor, indicating that consumers will have the willingness to buy and consume irradiated mangoes. Irradiation of mangoes can be a successful post-harvest treatment as an alternative to the hot water treatment.

  5. 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)

  6. Benchmark IMRT evaluation of a Co-60 MRI-guided radiation therapy system.

    PubMed

    Wooten, H Omar; Rodriguez, Vivian; Green, Olga; Kashani, Rojano; Santanam, Lakshmi; Tanderup, Kari; Mutic, Sasa; Li, H Harold

    2015-03-01

    A device for MRI-guided radiation therapy (MR-IGRT) that uses cobalt-60 sources to deliver intensity modulated radiation therapy is now commercially available. We investigated the performance of the treatment planning and delivery system against the benchmark recommended by the American Association of Physicists in Medicine (AAPM) Task Group 119 for IMRT commissioning and demonstrated that the device plans and delivers IMRT treatments within recommended confidence limits and with similar accuracy as linac IMRT.

  7. 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)

  8. Sobre el estado evolutivo de β Pictoris

    NASA Astrophysics Data System (ADS)

    Brunini, A.; Benvenuto, O. G.

    Desde el descubrimiento de fuertes excesos infrarrojos en β Pictoris, esta estrella ha sido muy estudiada y es considerada candidata a poseer un sistema planetario propio. β Pic está rodeada de un disco asimétrico de polvo que se observa de canto y que esta vacío a distancias <= 40 AU. Esto se considera una fuerte evidencia en favor de la presencia de (al menos) un planeta gigante. Recientemente se han observado líneas de material circunestelar que se han interpretado como consecuencia de la caída de objetos cometarios sobre esta estrella. Recientemente se ha utilizado la existencia del disco de polvo para atribuir una edad corta (pre - secuencia principal) a βPic. Sin embargo, la evaporación de estos cometas provee suficiente polvo como para explicar la presencia del disco observado sin necesidad de edades cortas. En este trabajo mostramos que la comparación entre la tasa de impactos cometarios estimada en el Sistema Solar para diferentes etapas de su evolución y los datos observados en β Pic indica edades avanzadas para β Pic. Esta estimación debe tomarse con cautela ya que depende de la estructura de los sistemas planetarios. Además mostramos que, desde el punto de vista de la evolución estelar y con las incertezas presentes en la luminosidad y la temperatura efectiva, existe un continuo de edades posible para β Pic. Sin embargo, empleando los datos provenientes de los flujos cometarios encontramos que una edad prolongada es consistente con ambos tratamientos.

  9. Sobre os sistemas de referência celeste

    NASA Astrophysics Data System (ADS)

    Poppe, P. C. R.; Martin, V. A. F.

    2003-02-01

    Apresentamos neste trabalho, algumas discussões sobre os sistemas de referência utilizados em Astronomia. Claramente, não é possível esgotar todo este assunto num único texto, mas esperamos, contudo, que o presente material possa ser apreciado nos cursos de Introdução à Astronomia, que estão cada vez mais presentes nas atuais propostas curriculares das graduações de Física. As discussões pertinentes às "Bases de Referência Celeste", serão apresentadas em um outro trabalho.

  10. Stromal damage in the mouse small intestine after Co60 gamma or D-T neutron irradiation

    SciTech Connect

    Carr, K.E.; Hamlet, R.; Nias, A.H.; Boyle, F.C.; Fife, M.G.

    1985-01-01

    Stromal constituents have been examined in mouse small intestine 3 1/2 days after irradiation with either 18-20 Gy gamma rays or 10 Gy neutrons. These doses were chosen for their equivalent effect on the number of intestinal crypts found after treatment. Despite the fact that the topography of the villi, as imaged by scanning electron microscopy, was altered by treatment, with gamma irradiated villi showing lateral or horizontal collapse while neutron irradiation produced conical villi, few changes were seen in the villous stromal compartments. There were, however, ultrastructural changes observed in the stroma of the pericryptal plate. Changes common to both radiation schedules included disorganisation of the subepithelial stroma and an increase in the number of irregular processes. Some changes after irradiation, however, were not identical in the two groups. Gamma irradiation resulted in pale, foamy cytoplasmic vesicles, the separation of smooth muscle cells and changes in the structure of the luminal aspect of arterial blood vessels while neutron irradiation produced dense cytoplasmic vesicles and electron dense bodies within the substance of peripheral nerve twigs. The fact that the variation in the topography of villi after the two types of radiation is matched by changes in the deep stroma rather than within the villi themselves indicates that the stromal pericryptal plate is of importance in the structure of the villus and the extent to which the villi have varied from the normal finger shaped structure.

  11. 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.

  12. 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

  13. Treatment of radioactive liquid waste (Co-60) by sorption on Zeolite Na-A prepared from Iraqi kaolin.

    PubMed

    Mustafa, Yasmen A; Zaiter, Maysoon J

    2011-11-30

    Iraqi synthetic zeolite type Na-A has been suggested as ion exchange material to treat cobalt-60 in radioactive liquid waste which came from neutron activation for corrosion products. Batch experiments were conducted to find out the equilibrium isotherm for source sample. The equilibrium isotherm for radioactive cobalt in the source sample showed unfavorable type, while the equilibrium isotherm for the total cobalt (the radioactive and nonradioactive cobalt) in the source sample showed a favorable type. The ability of Na-A zeolite to remove cobalt from wastewater was checked for high cobalt concentration (822 mg/L) in addition to low cobalt concentration in the source sample (0.093 mg/L). A good fitting for the experimental data with Langmuir equilibrium model was observed. Langmuir constant qm which is related to monolayer adsorption capacity for low and high cobalt concentration was determined to be 0.021 and 140 mg/g(zeolite). The effects of important design variables on the zeolite column performance were studied these include initial concentration, flow rate, and bed depth. The experimental results have shown that high sorption capacity can be obtained at high influent concentration, low flow rate, and high bed depth. Higher column performance was obtained at higher bed depth. Thomas model was employed to predict the breakthrough carves for the above variables. A good fitting was observed with correlation coefficients between 0.915 and 0.985. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. 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.

  15. Avisos de salud sobre el PFOA y PFOS en el agua potable

    EPA Pesticide Factsheets

    La EPA estableció avisos de salud sobre el ácido perfluorooctanoico (PFOA) y el sulfonato de perfluorooctano (PFOS) para proporcionar información a los operadores de sistemas de agua potable y funcionarios estatales, tribales y locales sobre los riesgos de

  16. Hoja informativa sobre la Agenda de Acción EJ 2020

    EPA Pesticide Factsheets

    Página principal de la hoja informativa sobre la Agenda de Acción EJ 2020 de la Agencia de Protección Ambiental de EE.UU. que delinea el plan estratégico de justicia ambiental de la agencia para los próximos cuatro años.

  17. 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…

  18. Obtenga más información sobre la etiqueta Safer Choice

    EPA Pesticide Factsheets

    Entérese más acerca del programa EPA Diseño para el medio ambiente, incluyendo información sobre su historia, proyectos anteriores y otros programas de la EPA que están relacionados con este programa.

  19. Effects of an acute bout of exercise on serum soluble leptin receptor (sOB-R) levels.

    PubMed

    Yang, Chung Bing; Chuang, Chung-Chief; Kuo, Chung Sen; Hsu, Chin Hsing; Tsao, Te Hung

    2014-01-01

    We investigated the effects of an acute bout of exercise on serum soluble leptin receptor (sOB-R) concentrations. Eighteen male participants completed two different exercise sessions with intensities of 25% and 65% maximal aerobic capacity (VO2max). In addition to the energy expenditure during exercise sessions being measured, blood samples were collected before exercise, and immediately, at 24 h, and at 48 h post-exercise to analyse sOB-R, leptin and insulin levels. At 24 h post-exercise, sOB-R and leptin concentrations at the 65% VO2max were significantly different from those at the 25% VO2max. Leptin levels at 48 h post-exercise were also significantly lower for the 65% VO2max than for the 25% VO2max (P < 0.01). In the 65% VO2max session, the energy expenditure during exercise was significantly associated with leptin concentrations at 24 h and 48 h and sOB-R concentrations at 24 h post-exercise. However, no correlations were found between sOB-R and leptin at the three post-exercise time points. In conclusion, an acute bout of exercise with 920 kcal of output resulted in an increase in sOB-R levels at 24 h post-exercise. However, the changes in sOB-R levels due to an acute bout of exercise might not contribute to the delayed decrease observed for leptin.

  20. 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

  1. Origin of the redshift of the luminescence peak in InGaN light-emitting diodes exposed to Co-60 γ-ray irradiation

    NASA Astrophysics Data System (ADS)

    Li, Y. L.; Wang, X. J.; He, S. M.; Zhang, B.; Sun, L. X.; Li, Y. D.; Guo, Q.; Chen, C. Q.; Chen, Z. H.; Lu, W.

    2012-12-01

    The redshift (˜54 meV) of the photoluminescence (PL) peak energy of blue InGaN/GaN light-emitting diodes exposed to 60Co γ-rays was observed. Time-resolved PL indicates that the PL radiative time increases along with irradiation does. The temperature-dependent PL and photoreflectance techniques show that γ-ray irradiance leads to higher carrier localization energies and larger Stokes' shift, respectively. These facts suggest that the redshifts of the PL peak emission introduced by γ-ray irradiance mainly originated from the enhancement of indium fluctuation. The cathodoluminescent images of the samples before and after γ-ray irradiation are compared to verify the results.

  2. A comparative planning study for lung SABR between tri-Co-60 magnetic resonance image guided radiation therapy system and volumetric modulated arc therapy.

    PubMed

    Park, Jong Min; Park, So-Yeon; Kim, Hak Jae; Wu, Hong-Gyun; Carlson, Joel; Kim, Jung-In

    2016-08-01

    To compare the plan quality of tri-(60)Co magnetic-resonance image-guided radiation therapy (IGRT) to that of volumetric modulated arc therapy (VMAT) for lung stereotactic ablative radiotherapy (SABR). A total of 22 patients with lung tumors located in the lower lobe were selected retrospectively. For each patient, VMAT plans with linac and intensity-modulated radiation therapy (IMRT) plans with the tri-(60)Co system were generated with prescription doses of 60Gy (daily dose=15Gy). For both plan types, identical CT image sets and structures were used, with the exception of planning target volumes (PTV). The PTV for VMAT was generated from the internal target volume (ITV) while the PTV for the tri-(60)Co system was generated from the gross tumor volume (GTV). Clinically relevant dose-volumetric parameters were calculated and analyzed. The average PTV volumes of tri-(60)Co plans and VMAT plans were 10.5±12.3cc vs. 27.2±23.5cc, respectively (p<0.001). The maximum and mean doses to PTVs were 64.0±2.6Gy vs. 62.5±0.9Gy (p=0.005) and 61.4±1.7Gy vs. 60.0±0.5Gy (p<0.001), respectively. The conformity and homogeneity indices were 1.89±0.38 vs. 1.01±0.40 (p<0.001) and 0.06±0.02 vs. 0.04±0.00 (p<0.001), respectively. No considerable differences for organs at risk (OARs) were observed between tri-(60)Co plans and VMAT plans. In terms of target conformity, integral dose and lung mean dose, the plan quality of tri-(60)Co plans was inferior to that of VMAT plans when the PTV volumes of tri-(60)Co plans were less than 10cc. However, all treatment plans of tri-(60)Co system were clinically acceptable. For lung SABR, the quality of ITV-based VMAT plans was better than that of GTV-based tri-(60)Co plans especially when the PTV volumes of the tri-(60)Co plans were less than 10cc. If the breathing pattern of a patient is reproducible, VMAT is considered the optimal option for lung SABR, otherwise the tri-(60)Co IGRT should be considered due to the ability to monitor tumor motion during treatment. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  3. Effects of whole body CO60 irradiation on the male genital tract of gerbil (Meriones hurrianae), hedgehod (hemiechinus auratus Collaris), and house rat (Rattus rattus Rufescens).

    PubMed

    Dixit, V P

    1977-06-01

    1. The effects of 400 and 575 rads of whole body irradiation in gerbil (Meriones hurrianae), hedgehog (Hemiechinus auratus Collaris) and house rat have been studied with a view to compare the effects of irradiation on the desert mammalian species with those of domestic ones. 2. Typical signs and symptoms of radiation sickness, transient body loss and radiation mortality in gerbils and house-rats were apparent, whereas the hedgehogs were not affected at this dose level. 3. Extensive necrosis, exfoliation of seminiferous element, intertubular edema and shrinkage of the seminiferous tubule and Leydig cell nuclei in gerbils and house-rats were conspicuous in histological preparations. Mild regressive tubular lesions were also observed in hedgehogs treated with 575R. 4. Whole body irradiation depleted the RNA, protein and sialic acid contents of the testes. High cholesterol contens in the testes of irradiated gerbil, hedgehog and house rats identified this as the site of degenerating cells and fragments. 5. Reduced androgen production was confirmed in non active Leydig cells and decreased fructose contents in the seminal vesicles of gerbil and house rats. At 575 R dose level, hedgehog was comparatively radio-resistant. But at 875 R extensive damage to the reproductive organs could be noticed.

  4. Variability in cytogenetic adaptive response of cultured human lymphocytes to mitomycin C, bleomycin, quinacrine dihydrochloride, Co60 gamma-rays and hyperthermia.

    PubMed

    Krishnaja, A P; Sharma, N K

    2008-03-01

    Adaptive response (AR) is a well-documented phenomenon by which cells or organisms exposed to low dose of a genotoxicant become less sensitive to subsequent high-dose exposure to the same or another genotoxicant. AR, if induced can modify the efficacy leading to drug or radio-resistance, during anti-neoplastic drug or radiation treatment. Contradictions exist in AR induction by different genotoxicants with respect to the biomarkers, time schedules, and inter-individual variability, reflecting the complexity of AR in eukaryotic cells. In order to further ascertain these factors, AR induced by anti-neoplastic agents mitomycin C (MMC), bleomycin (BLM) and chemosterilant quinacrine dihydrochloride was examined in different donors and time schedules using cytogenetic biomarkers chromosome aberrations, sister chromatid exchanges and micronuclei (MN). BLM- and hyperthermia (HT)-induced cross-resistance to gamma rays and MMC/BLM, respectively, was also studied. Difference between MMC- and BLM-induced protective effects in biomarkers examined in the same donors was noticed. Adaptation to BLM and HT showed cross-resistance to chromosome damage induction by gamma rays and BLM/MMC, respectively. Cell cycle analysis indicated that adaptation is not caused by change in the rate of cell proliferation after challenge dose. MN as a chromosomal biomarker in large-scale population studies on AR is advocated, based on similar AR induced in all donors by MMC/BLM and rapid assessment in binucleated cells. Influence of certain genotypes on chromosomal biomarkers used in AR studies and role of AR in radiation and chemotherapy need to be further deciphered.

  5. Sobre la terapia génica para enfermedades de la retina.

    PubMed

    Fischer, M Dominik

    2017-07-11

    Las mutaciones en un gran número de genes provocan degeneración de la retina y ceguera sin que exista actualmente cura alguna. En las últimas décadas, la terapia génica para enfermedades de la retina ha evolucionado y se ha convertido en un nuevo y prometedor paradigma terapéutico para estas enfermedades poco comunes. Este artículo refleja las ideas y los conceptos que parten de la ciencia básica hacia la aplicabilidad de la terapia génica en el ámbito clínico. Se describen los avances y las reflexiones actuales sobre la eficacia de los ensayos clínicos en la actualidad y se discuten los posibles obstáculos y soluciones de cara al futuro de la terapia génica para enfermedades de la retina. © 2017 S. Karger AG, Basel.

  6. Información general sobre la preparación y la respuesta frente a desastres naturales

    EPA Pesticide Factsheets

    Esta página brinda información general sobre la manera en que se puede preparar para enfrentar desastres naturales potenciales y las acciones a tomar después de dichos desastres naturales y otras emergencias ambientales.

  7. 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

  8. 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

  9. 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

  10. 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.

  11. 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.

  12. Desarrollo de fotonovelas para concienciar sobre trastornos de la conducta alimentaria en latinos en los Estados Unidos

    PubMed Central

    Reyes-Rodríguez, Mae Lynn; García, Marissa; Silva, Yormeri; Sala, Margarita; Quaranta, Michela; Bulik, Cynthia M.

    2016-01-01

    Resumen El objetivo de este estudio fue desarrollar fotonovelas, un tipo de novela gráfica popular en la población latina, para crear conciencia y educar sobre los trastornos de la conducta alimentaria (TCA). Cuatro caricaturas ilustradas y guiones adaptados para adultos y adolescentes de ambos sexos fueron presentados en discusiones focales y en una entrevista de profundidad. Diecisiete latinos adultos (14 mujeres; 3 hombres) y 10 adolescentes (9 féminas; 1 varón) participaron en el estudio. Los participantes encontraron las fotonovelas interesantes y que captaban más la atención que los folletos tradicionales. El uso del espanglish y la clarificación de las diferencias entre los TCA fueron sugeridos por las adolescentes femeninas. Los adultos varones sugirieron cambiar el título, que se enfocara en las consecuencias en la salud de los TCA para que llame la atención en los hombres a leer la historia. Basado en la aceptación encontrada en este estudio, la fotonovela pudiera ser una avenida prometedora para crear conciencia y educar a la comunidad latina sobre los TCA en los Estados Unidos. PMID:27313838

  13. 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

  14. Human breast milk and adipokines--A potential role for the soluble leptin receptor (sOb-R) in the regulation of infant energy intake and development.

    PubMed

    Zepf, F D; Rao, P; Moore, J; Stewart, R; Ladino, Yuli Martinez; Hartmann, B T

    2016-01-01

    Concentrations of different adipokines in human breast milk are thought to be able to affect energy intake of the infant. Leptin is a hormone synthesized by adipose tissue and the human placenta and favors satiety. The availability of leptin in breast milk is influenced by epithelial cells of the mammary gland that are known to be able to produce leptin, as well as leptin from maternal circulation that is transported to the breast milk, and which can thus in turn reach neonatal blood after absorption. Research so far as mainly focused on leptin concentrations in breast milk. However, evidence suggests that in addition to leptin concentrations levels of the so-called soluble leptin receptor (sOb-R), the main high-affinity binding protein for leptin in humans, are necessary in order to calculate the free leptin index (FLI) and to assess function of the leptin axis. FLI is calculated from the ratio of leptin to the sOb-R, and serves as the main parameter for assessing function of the leptin axis throughout maturation and development. Here we propose that assessing sOb-R levels in addition to leptin concentrations in breast milk could serve as a valuable tool to investigate effects of the leptin axis in breast milk because sOb-R concentrations can impact available leptin levels, and which in turn can have significant implications for infant energy intake and related development.

  15. 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

  16. 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.

  17. Actitud y conocimiento sobre donación de órganos de estudiantes de medicina de una universidad pública del noreste de México.

    PubMed

    Sebastián-Ruiz, María José; Guerra-Sáenz, Elda Karina; Vargas-Yamanaka, Anna Karen; Barboza-Quintana, Oralia; Ríos-Zambudio, Antonio; García-Cabello, Ricardo; Palacios-Saucedo, Gerardo Del Carmen

    2017-01-01

    Averiguar la actitud y el conocimiento que tienen los estudiantes de medicina de una universidad pública del noreste de México sobre la donación de órganos y tejidos. Estudio prolectivo, descriptivo, observacional y transversal. Se incluyeron 3056 encuestas de 34 reactivos realizadas a estudiantes de medicina durante el periodo 2013-2015 y se eliminaron aquellas con menos del 80% de los reactivos contestados. Análisis estadístico: frecuencias absolutas, porcentajes, medias, desviación estándar y prueba de ji al cuadrado. Se consideró significativo un valor de p < 0.05. El 74% de los estudiantes donaría sus órganos y el 41% lo haría por reciprocidad; del 26% que no donaría sus órganos, el 48% no lo haría por temor a que tomen sus órganos antes de estar muerto. Un 86% estaría dispuesto a donar los órganos de algún familiar. El 64% ha comentado el tema de la donación con su familia y el 67% con amigos. El 50% no ha recibido información alguna sobre el tema. El 68% entiende el concepto de muerte encefálica. Pocos estudiantes reciben información sobre donación de órganos al llegar a la universidad; pese a ello, la mayoría tiene una actitud positiva y estarían -dispuestos a -donar. The issue of organ donation is scarcely addressed during undergraduate medical studies. To evaluate the knowledge and attitude towards organ donation of medicine students of a Northwestern Mexico public university. A prolective, descriptive, observational, and cross-sectional study. A 34 items cross-sectional survey evaluating knowledge and attitude towards organ donation in 3056 medicine students during 2013-2015. Descriptive statistics were used as absolute frequencies, percentages, mean and standard deviation, as well as the Chi-square test. A p < 0.05 was considered significant. 74% of students would donate their own organs, mainly due to reciprocity (41%). 26% of students would not donate, 48% of them because of fear that their organs could be taken before death

  18. Concepciones y concepciones alternativas de estudiantes universitarios/as de biologia y futuros maestros/as de Ciencia de escuela secundaria sobre la teoria de evolucion biologica por seleccion natural

    NASA Astrophysics Data System (ADS)

    Morales Ramos, Egda M.

    La teoria de evolucion biologica (TEB) por seleccion natural es uno de los conceptos unificadores mas importantes del curriculo de Biologia. En Puerto Rico se han hecho pocas investigaciones que abunden sobre las concepciones y concepciones alternativas (CA) que tienen los estudiantes universitarios/as de Biologia y los maestros/as de Ciencia del nivel secundario sobre esta teoria. La politica publica educativa actual establece mediante documentos normativos como los Estandares de contenido y Expectativas de grado del Programa de Ciencias [Puerto Rico Core Standards] la ensenanza de esta teoria. Sin embargo, no se encontraron preguntas sobre la seleccion natural en los ejercicios de practica provistos por el Departamento de Educacion para las pruebas estandarizadas lo cual puede influir para que no se ensene adecuadamente. Las preguntas de investigacion fueron 1. ¿Cuales son las concepciones y concepciones alternativas de estudiantes universitarios/as y de los futuros maestros y maestras de Ciencia sobre la TEB? 2. ¿Cuales conceptos que seleccionan los estudiantes universitarios/as y los futuros maestros y maestras de Ciencia sobre la TEB coinciden con lo aceptado como valido por la comunidad cientifica? y 3. ¿Como comparan las respuestas de la prueba original. v. Entendiendo el cambio biologico que mide concepciones y CA sobre la TEB por seleccion natural, con las de la traducida al idioma espanol? Se utilizo el metodo cuantitativo con un diseno de investigacion transversal por encuesta. La tecnica principal para recopilar los datos fue una prueba con doce items, que formo parte de un instrumento para el cual se recopilaron diversas fuentes de evidencia acerca de su validez. Las muestras estuvieron formadas por 69 estudiantes de Ciencias Naturales y por 16 estudiantes futuros maestros y maestras del nivel secundario de la UPR-RP. Se utilizaron estadisticas descriptivas, analisis de Ji cuadrado y se calcularon los coeficientes alfa de Cronbach y de Spearman

  19. 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.

  20. 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

  1. Conceptos Basicos Sobre el Propano

    SciTech Connect

    2016-08-01

    El propano provee energia a mas de 143.000 vehiculos en los Estados Unidos y 23 millones en todo el mundo. Flotas de todos los Estados Unidos han implementado con exito el uso de vehiculos que funcionan con gas propano, y en la actualidad varios funcionan gracias a este gas, incluyendo autobuses escolares, lanzaderas y autobuses publicos, asi como tambien furgonetas, taxis, vehiculos utilizados por las fuerzas del orden, barredoras de calles y camiones para uso profesional. El propano tambien se utiliza con frecuencia en aplicaciones fuera de la carretera, tales como montacargas, podadoras y equipos de uso profesional y otros equipos agricolas. Las ventajas del propano incluyen la disponibilidad interna, su rendimiento y el hecho de que genera menos emisiones de gases contaminantes que otras alternativas energeticas.

  2. 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

  3. 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.

  4. 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.

  5. 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

  6. 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

  7. 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

  8. [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.

  9. 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.

  10. 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

  11. Conceptos Basicos Sobre el Gas Natural

    SciTech Connect

    2016-08-01

    El gas natural abastece cerca de 150.000 vehiculos en los Estados Unidos y aproximadamente 22 millones de vehiculos en todo el mundo. Los vehiculos de gas natural (NGV, por sus siglas en ingles) son una buena opcion para las flotas de vehiculos de alto kilometraje, tales como autobuses, taxis, vehiculos de recoleccion de basura, los cuales son alimentados centralmente u operan dentro de un area limitada o a lo largo de una ruta con estaciones de servicio de gas natural. Las ventajas del gas natural como combustible alternativo incluyen su disponibilidad interna, la red de distribucion establecida, un costo relativamente bajo, y los beneficios de las emisiones.

  12. Investigaciones sobre cascadas electromagnéticas

    NASA Astrophysics Data System (ADS)

    Orellana, M.; Pellizza, L.; Romero, G. E.

    Results from the latest generations of telescopes have revealed a rich sky at high and very high energies with more than a thousand sources at GeV energies and more than a hundred sources at TeV energies. The sources are galactic and extra-galactic natural particle accelerators where emission processes operate efficiently at the gamma-ray domain. The development of pair-photon cascades within the source or along the line of sight may modify the originally emitted spectrum. This effect should be included in our interpretation of the observations in order to progress in the understanding of the physical origin of the emission. Through numerical simulations; we follow the three-dimensional trajectories of such cascades. I here report on the status of our investigations; with focus on the propagation through the background photon fields. FULL TEXT IN SPANISH

  13. 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)

  14. 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)

  15. 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)

  16. 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)

  17. 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…

  18. 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)

  19. 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…

  20. 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)

  1. 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.

  2. 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

  3. 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

  4. 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.

  5. 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

  6. 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.

  7. 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

  8. 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…

  9. [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,…

  10. Posible influencia de exoplanetas sobre la actividad estelar: nuevos resultados

    NASA Astrophysics Data System (ADS)

    Flores, M. G.; Collado, A. E.; Jaque Arancibia, M.; Saffe, C. E.; Buccino, A. P.

    2017-10-01

    Our main aim of this work is to analyze 2 phenomena possibly related and at the same time very discussed in the literature. On the one hand, the difference in the activity levels shown by stars with and without planets. On the other hand, the excess of Lithium (Li) depletion presented by stars with planets when they are compared to stars with similar characteristics that do not host planets. To reach our main aim, the work has been divided into 3 stages. Thus, in this second contribution we present an analysis of the activity indexes calculated for the whole sample. To do so, we used high resolution spectra () of 1004 FGK stars taken with the HARPS (High Accuracy Radial Velocity Planet Searcher) spectrograph, installed in the 3.6 m ESO telescope. We do not find a significant difference in the activity indexes of stars with and without planets. Furthermore, the chromosphere activity is not correlated with the mass of the planet.

  11. 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…

  12. Información general sobre los mosquitos

    EPA Pesticide Factsheets

    Una consecuencia más importante de algunas picaduras de mosquitos es la trasmisión de ciertas enfermedades graves como el paludismo, la fiebre del dengue y varias formas de encefalitis, que incluyen el virus del Nilo occidental.

  13. 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)

  14. Primeros resultados sobre el estudio de oscilaciones no radiales

    NASA Astrophysics Data System (ADS)

    Córsico, A.; Benvenuto, O. G.

    En el Observatorio de La Plata se ha comenzado a elaborar un código de pulsaciones el cual resuelve el problema de las oscilaciones no radiales en el caso adiabático. Dicho código está basado en la técnica de diferencias finitas ampliamente usado en cálculos de estructura y evolución estelar. En este trabajo se presentan los primeros resultados encontrados aplicando el código mencionado al caso de una polítropa de índice n=3. Se presentan los valores de las autofrecuencias y las autofunciones para diferentes modos de pulsación de dicha configuración politrópica. En un futuro próximo, se aplicará este programa al estudio de las pulsaciones no radiales de estrellas enanas blancas.

  15. Pensamientos Sobre (Thoughts on) Teaching English as a Second Language.

    ERIC Educational Resources Information Center

    Ulibarri, Mari-Luci

    This document presents ideas on various topics in teaching English as a second language. Some of the problems of English orthography and semantics are illustrated. The role of contrastive analysis is mentioned with Spanish-English illustrations. A list of second-language-acquisition principles and techniques is provided, and suggestions for…

  16. 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)

  17. 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…

  18. 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…

  19. 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)…

  20. 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;…

  1. 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)…

  2. Sobre prestamos y clasificaciones linguisticas (Regarding Borrowing and Linguistic Classification).

    ERIC Educational Resources Information Center

    Key, Mary Ritchie

    1988-01-01

    This article explores the traditionally accepted etymologies of several lexical borrowings in the indigenous languages of the Americas within the framework of comparative linguistics and linguistic classification. The first section presents a general discussion of the problem of tracing lexical borrowings in this context. The section features a…

  3. 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…

  4. Posible influencia de exoplanetas sobre la actividad estelar

    NASA Astrophysics Data System (ADS)

    Flores, M.; Saffe, C.; Buccino, A. P.; Jaque Arancibia, M.; Mauas, P.

    2016-08-01

    The aim of this work is to analize the possible difference in the levels of activity showed by stars with and without planets. Several authors have suggested that stars with planets, in particular those with hot-Jupiter-like planets, have activity levels greater than those showed for stars of the same spectral class, but without planets. In this contribution we present the analysis of chromospheric activity indexes for 353 objects. To do so, we used high-resolution spectra () of F-, G-, and K-type stars taken with the High Accuracy Radial velocity Planet Searcher spectrograph, installed at the 3.6 m ESO telescope. We do no find a significant difference in the activity indexes of stars with and without planets.

  5. 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…

  6. [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…

  7. Leamos Sobre Veinte Ocupaciones! Twenty Trades to Read About.

    ERIC Educational Resources Information Center

    Lamatino, Robyn; Mintz, Adin

    Twenty trades are explored in this bilingual supplementary workbook, designed specifically for native Spanish speakers who are in the process of learning English. The purpose of this book is to ease the Spanish-speaking student from his/her native language into English with as little discomfort as possible. There are twenty chapters in the book…

  8. 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…

  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. Gobierno Federal Contina Investigacin Cientfica Sobre Erupciones en Flint

    EPA Pesticide Factsheets

    Flint, MICH. (24 de marzo, 2016) - Los expertos federales, del estado y del condado de salud y agua entienden que los residentes de Flint están preocupados por la calidad general de su agua-tanto como para beber y para bañarse. En este momento, el an

  11. 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…

  12. 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…

  13. Los ojos de la NASA sobre la Tierra

    NASA Image and Video Library

    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...

  14. 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…

  15. Informe Sobre la Conferencia (Think Tank) de Aspira Nacional Sobre Education Bilingue (Aspira National Think Tank Report: Bilingual Education)

    ERIC Educational Resources Information Center

    Aspira, Inc., New York, NY.

    This Spanish edition reports on the Aspira National Think Tank Conference attended by educational leaders and social scientists representing the major bilingual communities namely, Puerto Ricans, Mexicans, and Cubans. The conference studied four major topics: (1) equality and not similarity, theory, rationale, and objectives of bilingual…

  16. Submicron Co(TaC) line array produced by electron-beam direct writing

    NASA Astrophysics Data System (ADS)

    Zhao, Y.; Zhou, T. J.; Wang, J. P.; Thong, J. T. L.; Yao, X. F.; Chong, T. C.

    2003-05-01

    (Co60C40)97Ta3 and Co60C40 films with thickness 30 nm were prepared by cosputtering Co, Ta, and C onto C-buffered glass substrates. The as-deposited (Co60C40)97Ta3 and Co60C40 films were amorphous and nonferromagnetic. These films became magnetic upon annealing and the magnetic performance of annealed (Co60C40)97Ta3 films are better than that of annealed Co60C40 films at the same annealing condition. Magnetic patterning (line array) of the as-deposited (Co60C40)97Ta3 films was realized by subjecting it to electron-beam radiation using a focused 30 keV beam with a current of 7.1 nA and a dwell time per line of 0.75 s and longer. By increasing the dwell time, the whole region where an electron beam was scanned became magnetic with clear domain structures because of thermally activated diffusion. The required dwell time of magnetically patterning nonmagnetic (Co60C40)97Ta3 thin films (0.75 s) is much shorter than that of Co60C40 films (3.8 s). The magnetic measurements show that the lines [(Co60C40)97Ta3] and dots (Co60C40) are magnetically soft. The present method of magnetically patterning a nonmagnetic film has potential application for nanoscale solid magnetic devices.

  17. 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

  18. 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…

  19. 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…

  20. 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…

  1. 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:…

  2. 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.

  3. 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,…

  4. 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…

  5. 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…

  6. 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…

  7. 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…

  8. 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,…

  9. SOBR: A High-Performance Shared Output Buffered Router for Networks-on-Chip

    NASA Astrophysics Data System (ADS)

    Chen, Yancang; Xie, Lunguo

    This paper presents a single-cycle shared output buffered router for Networks-on-Chip. In output ports, each input port always has an output virtual-channel (VC) which can be exchanged by VC swapper. Its critical path is only 24 logic gates, and it reduces 9.4% area overhead compared with the classical router.

  10. 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)

  11. Nota sobre el "Se" como Sujeto Indefinido (A Note on "Se" as an Indefinite Subject)

    ERIC Educational Resources Information Center

    Lujan, Marta

    1975-01-01

    Contradicts Pablo Jordan's theory that certain "se" constructions in Spanish are neither passive nor reflexive. It is claimed that syntactic evidence reveals two types of impersonal structures, the impersonal active and the passive reflexive. (Text is in Spanish.) (CK)

  12. Notas sobre dos autores mejicoamericanos de California (Notes on Two Mexican-American Authors in California).

    ERIC Educational Resources Information Center

    Moesser, Alba

    This paper discusses the work of two Mexican American authors, Jose A. Villerreal and Richard Vazquez, using "Pocho" by Villarreal and "Chicano" by Vazquez as the focus for discussion. Both authors describe the world of Mexican Americans and their social conditions, and both underscore the need for conserving their native…

  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. 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…

  15. 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)

  16. 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…

  17. Glasario de Terminos sobre Germinacion de Semillas para Especialistas en Arboles Semilleros

    Treesearch

    F.T. Bonner

    1985-01-01

    The glossary, written in Spanish, is designed for scientists and technicians concerned with testing or research with forest tree seeds. Definitions have been simplified as much as possible without sacrificing their technical meanings.

  18. 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.

  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. 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.

  1. 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…

  2. 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)

  3. Perspectiva General sobre la Sordo-Ceguera (Overview on Deaf-Blindness). DB-LINK.

    ERIC Educational Resources Information Center

    Miles, Barbara

    This overview provides basic information on the causes of deaf-blindness and the particular challenges faced by individuals who are deaf-blind. Causes of deaf-blindness include various syndromes, multiple congenital anomalies, prematurity, congenital prenatal dysfunction, and various postnatal causes. Differences between people deaf-blind from…

  4. Sobre Algumas Tecnicas de Perturbacao Utilizadas no Problema Ressonante 3/1

    NASA Astrophysics Data System (ADS)

    Balthazar, J. M.; Sagnier, J. L.; Ferraz Mello, S.; Koiller, J.; Yokoyama, T.

    1987-05-01

    ABSTRACT. This work concerns with the study of a particular 3/1 resonant problem for which we have determined formal solutions according to the model belonging to the domain of the Restricted Elliptic Problem of Three Bodies. Key & : ASTEROIDS

  5. 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…

  6. 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…

  7. 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,…

  8. 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)

  9. Informe sobre el proyecto contrastivo hispano-hungaro (Report on the Spanish-Hungarian Contrastive Project)

    ERIC Educational Resources Information Center

    Fulei-Szanto, Andres

    1974-01-01

    A description of a contrastive linguistics project in Hungary aiming to augment linguistic theories in the Spanish language and propound theories for scientific and artistic translation. (Text is in Spanish.) (CK)

  10. Informe sobre el proyecto contrastivo hispano-hungaro (Report on the Spanish-Hungarian Contrastive Project)

    ERIC Educational Resources Information Center

    Fulei-Szanto, Andres

    1974-01-01

    A description of a contrastive linguistics project in Hungary aiming to augment linguistic theories in the Spanish language and propound theories for scientific and artistic translation. (Text is in Spanish.) (CK)

  11. 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…

  12. 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…

  13. ¿Origen dinámico del polvo sobre la superficie de Iapetus?

    NASA Astrophysics Data System (ADS)

    Leiva, A. M.; Briozzo, C. B.

    We implement the three-dimensional Circular Restricted Three Body Prob- lem for low energy particles entering the Saturn­Iapetus system from the recently discovered dust ring. The distribution of impacts with the surface of Iapetus so obtained shows features resembling that of the dark regions observed in this satellite. FULL TEXT IN SPANISH

  14. 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)

  15. 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)

  16. Sobre las soluciones acotadas del problema instantáneo de dos cuerpos

    NASA Astrophysics Data System (ADS)

    Altavista, C.

    La demostración se basa en el hecho de que las integrales del problema de los N-cuerpos admiten componentes en el campo complejo según las raíces n-ésimas de la unidad. Definida la matriz unitaria correspondiente, la fórmula de Cayley permite transformar la matriz unitaria en una matriz hermitiana. Utilizando como parámetros los cosenos direccionales de un sistema de coordenadas orbitales referidos a un sistema de referencia fijo, puede construirse, utilizando el operador hermitiano antes definido, una forma cuadrática cuyas raíces mínima y máxima definen las cotas respectivas de los movimientos de los mencionados cosenos direccionales.

  17. 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,…

  18. 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…

  19. 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…

  20. 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…

  1. Sobre o uso das séries de Puiseux em mecanica celeste

    NASA Astrophysics Data System (ADS)

    Miloni, O. I.

    2003-08-01

    Neste trabalho é apresentada uma demonstração do uso dos diferentes desenvolvimentos em séries para as equações de perturbação em Mecânica Celeste no marco Hamiltoniano. Em trabalhos clássicos como os de Poincaré (Poincaré, 1893) por exemplo, já esta planteado o uso de potências não inteiras no pequeno parâmetro, o que evidencia a não analiticidade das funções quando uma ressonância ocorre. Nestes trabalhos os desenvolvimentos são na raíz quadrada da massa de Júpiter (o pequeno parâmetro). Mais recentemente (Ferraz-Mello, 1985) outros tipos de desenvolvimentos foram aplicados modificando substancialmente as ordens de grandeza e a velocidade de convergência das séries. Com esta abordagem, os desenvolvimentos foram expressados em termos da raíz cúbica do pequeno parâmetro. Neste trabalho apresentamos um enfoque geral, onde os diferentes tipos de desenvolvimentos em séries de Puiseux (Valiron, 1950) são obtidos a partir da aplicação de Teorema de Preparação de Weierstrass (Goursat, 1916) considerando a equação de Hamilton-Jacobi como uma equação algébrica. Os resultados são aplicados ao problema restrito dos três corpos em ressonância de primeira ordem e, dependendo da grandeza da excentricidade do asteróide em relação à de Júpiter, obtemos os diferentes desenvolvimentos, em raíz quadrada ou raíz cúbica da massa de Júpiter.

  2. 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…

  3. Recent status on cobalt-60 gamma ray radiation sources production and its application in China

    NASA Astrophysics Data System (ADS)

    Zhijian, Cao; Yunjiang, Song; Chunchua, Zhang; Maoling, Li

    1993-07-01

    This paper describes the recent status on Co-60 γ ray radiation sources production and its application in China. At present, the production capacity of Co-60 γ ray radiation sources in China is about 11.1 PBq(0.3 MCi) per year, 5 years later, it can increase to 37 PBq(1 MCi) per year. The standard dimension of Co-60 γ ray radiation sources is φ 15×90 mm, the radioactivity of each sources is 370TBq - 740TBq(1000-2000 Ci). There are over 150 Co-60 γ ray radiation facilities with total design capacity of over 370 PBq(10 MCi) and practical capacity of about 92.5 PBq(2.5 MCi) in operation. The number of Co-60 γ ray radiation facilities with practical capacity of over 3.7 PBq(0.1 MCi) is 14. The main applications of the Co-60 γ ray sources are radiation crosslinking application, radiation sterilization of disposable medical supplies and food irradiation. The prospect of Co-60 γ ray radiation sources production and its application in China is good.

  4. 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.

  5. 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.

  6. The role of Cobalt-60 in modern radiation therapy: Dose delivery and image guidance.

    PubMed

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

    2009-07-01

    The advances in modern radiation therapy with techniques such as intensity-modulated radiation therapy and image-guided radiation therapy (IMRT and IGRT) have been limited almost exclusively to linear accelerators. Investigations of modern Cobalt-60 (Co-60) radiation delivery in the context of IMRT and IGRT have been very sparse, and have been limited mainly to computer-modeling and treatment-planning exercises. In this paper, we report on the results of experiments using a tomotherapy benchtop apparatus attached to a conventional Co-60 unit. We show that conformal dose delivery is possible and also that Co-60 can be used as the radiation source in megavoltage computed tomography imaging. These results complement our modeling studies of Co-60 tomotherapy and provide a strong motivation for continuing development of modern Cobalt-60 treatment devices.

  7. Failures Of CMOS Devices At Low Radiation-Dose Rates

    NASA Technical Reports Server (NTRS)

    Goben, Charles A.; Price, William E.

    1990-01-01

    Method for obtaining approximate failure-versus-dose-rate curves derived from experiments on failures of SGS 4007 complementary metal oxide/semiconductor (CMOS) integrated circuits irradiated by Co60 and Cs137 radioactive sources.

  8. 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

  9. Minutes of the 39th Computer Resources Integration Management Meeting, 12 March 1991

    DTIC Science & Technology

    2007-11-02

    Ü z 3 o CO ü UJ LU ü Q 1X1 < z u_ < C0 CO &#60 s ü < Q w CO Q Q (0 a UJ co CO &#60 ü z 3 Q UJ LJL 0) 0) < ü z « Z...commercial vendors whose products must compete in the market - place. It is inappropriate for the design of those environments to be turned over, in effect

  10. 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

  11. 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

    USDA-ARS?s Scientific Manuscript database

    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...

  12. 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.

  13. 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.

  14. 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 and external…

  15. 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…

  16. 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…

  17. 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)

  18. 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

  19. 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)

  20. [Drug resistance in Mycobacterium tuberculosis. A multicenter study of the Barcelona area. Grupo de Trabajo sobre Resistencias en Tuberculosis].

    PubMed

    Martin-Casabona, N; Alcaide, F; Coll, P; González, J; Manterola, J M; Salvadó, M; Caylà, J A

    2000-10-21

    The aims of this multicenter study was to establish the level of primary and acquired drug resistance of M. Tuberculosis strains isolated in Barcelona and to identify possible risk groups using clinical data. All tuberculosis patients with isolation and identification of M. tuberculosis strains from October 1995 to September 1997 were included. Susceptibility tests isoniazid, rifampin, ethambutol, streptomycin and pyrazinamide were performed using the Bactec 460 system and the proportions method on solid medium. Logistic progression was used for statistical analysis. The total number of patients included was 1,749 (1,535 non-treated and 214 previously treated). Primary drug resistance was 5.7% (isoniazid 3.8%; rifampin 1.0%, streptomycin 2.1%, ethambutol 0.3% and pyrazinamide 1.0%). Acquired drug resistance was 20.5% (isoniazid 17.3%, rifampin 9.8%, ethambutol 1.9%, streptomycin 4.7% and pyrazinamide 6.5%). Primary drug resistance was associated with people over 60 years old and women. The low level of drug resistance enables antituberculosis treatment of non-treated patients to start with the standardised three-drug regimes except in the case of foreign people from countries with a high level of drug resistance. Susceptibility tests are recommended on all M. tuberculosis strains isolated, together with controlled studies of drug resistance surveillance.

  1. 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…

  2. 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 and external…

  3. 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.

  4. 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…

  5. 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'…

  6. A Guide for Parents about Retention and Promotion = Una Guia para los Padres de Familia sobre Retencion y Promocion.

    ERIC Educational Resources Information Center

    State Univ. of New York, Oneonta. Coll. at Oneonta. Eastern Stream Center on Resources and Training.

    This bilingual (English and Spanish) brochure explains why retention is common among migrant students and what parents can do to help their children succeed in school. By second grade, nearly 50 percent of migrant students in the nation are older than their classmates and only about 50 percent of migrant students graduate from high school.…

  7. 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…

  8. [Sobre la (No) Responsabilidad de la Tecnociencia en los Problemas Ambientales y la Búsqueda de Política].

    PubMed

    Martínez Barrera, Jorge

    2016-01-01

    In this paper I propose to reflect upon modern configuration of technique, i.e., technoscience, and our responsibility towards environmental management. I show that the technological products of our world imply a certain attitude of aggression towards nature, contrasting with the attitude of protection from her, which was peculiar of the pre-technological world. Finally I suggest recovering the classical notion of politics as a possible alternative for controlling techno-scientific imperatives.

  9. 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…

  10. 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…

  11. "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)…

  12. 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'…

  13. "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)…

  14. 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.

    2015-10-23

    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.

  15. 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

  16. Impacto de la emisión de axiones sobre las propiedades evolutivas y pulsacionales de enanas blancas DB

    NASA Astrophysics Data System (ADS)

    Battich, T.; Althaus, L. G.; Córsico, A. H.

    2016-08-01

    White dwarfs are found to be good laboratories for studying the properties of fundamental particles such as the hypothetical axions. If these particles exist and interact with electrons, they would be emitted from the dense interior of white dwarfs, abandoning these stars without interact again, becoming an important energy sink. This would have a detectable effect on the evolutionary and pulsational properties of white dwarfs. This effect was already studied for DA white dwarfs (white dwarfs with a surface rich in hydrogen), but not for DB white dwarfs (hydrogen-deficient white dwarfs). We studied the general effect of axion emission on the evolution of DB white dwarfs and on the pulsational properties of DBV white dwarfs (pulsating DBs) with the aim of determining the potential of these stars to study the physics of axions. Moreover, we use an estimation of the rate of change of period of the DBV white dwarf PG 1351489 corresponding to the dominant period to derive a new limit on axion mass.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  18. DISYUNTIVAS EN LAS CONCEPCIONES SOBRE AUTONOMÍA Y BENEFICENCIA QUE AFECTAN LA TERAPÉUTICA DEL INTENTO SUICIDA.

    PubMed

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

    2010-06-01

    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.

  19. 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.…

  20. 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

  1. 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

  2. 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.

  3. Single Event Transient and TID Study in 28 nm UTBB FDSOI Technology

    NASA Astrophysics Data System (ADS)

    Liu, Rui; Evans, Adrian; Chen, Li; Li, Yuanqing; Glorieux, Maximilien; Wong, Richard; Wen, Shi-Jie; Cunha, Joao; Summerer, Leopold; Ferlet-Cavrois, Véronique

    2017-01-01

    Measuring single-event transient (SET) pulse widths is critical for developing proper mitigation schemes to single-event effects (SEE), especially for advanced technologies. This paper presents a test chip design implementing advanced techniques for measuring SETs implemented in a 28 nm Ultra-Thin Body and Box (UTBB) FDSOI technology. Experimental results of heavy ion and Co-60 irradiation experiments are presented. The heavy ion experiments confirm that this technology has very low SEE sensitivity. Laser test results show that pulse distortion (broadening) plays a key role when evaluating the effect of SETs. Total Ionizing Dose (TID) effects were also evaluated by measuring the Ring Oscillator (RO) frequencies and static current during heavy ion and Co-60 irradiation. Experimental results showed that the RO frequencies degraded up to 10% (heavy ion), and 40% (Co-60) after 1000 krad(Si) irradiation, but the logic in the chip functioned without error.

  4. Evaluation of SPE and GCR Radiation Effects in Inflatable, Space Suit and Composite Habitat Materials Project

    NASA Technical Reports Server (NTRS)

    Waller, Jess M.; Nichols, Charles

    2016-01-01

    The radiation resistance of polymeric and composite materials to space radiation is currently based on irradiating materials with Co-60 gamma-radiation to the equivalent total ionizing dose (TID) expected during mission. This is an approximation since gamma-radiation is not truly representative of the particle species; namely, Solar Particle Event (SPE) protons and Galactic Cosmic Ray (GCR) nucleons, encountered in space. In general, the SPE and GCR particle energies are much higher than Co-60 gamma-ray photons, and since the particles have mass, there is a displacement effect due to nuclear collisions between the particle species and the target material. This effort specifically bridges the gap between estimated service lifetimes based on decades old Co-60 gamma-radiation data, and newer assessments of what the service lifetimes actually are based on irradiation with particle species that are more representative of the space radiation environment.

  5. A national survey of HDR source knowledge among practicing radiation oncologists and residents: Establishing a willingness-to-pay threshold for cobalt-60 usage.

    PubMed

    Mailhot Vega, Raymond; Talcott, Wesley; Ishaq, Omar; Cohen, Patrice; Small, Christina J; Duckworth, Tamara; Sarria Bardales, Gustavo; Perez, Carmen A; Schiff, Peter B; Small, William; Harkenrider, Matthew M

    Ir-192 is the predominant source for high-dose-rate (HDR) brachytherapy in United States markets. Co-60, with longer half-life and fewer source exchanges, has piloted abroad with comparable clinical dosimetry but increased shielding requirements. We sought to identify practitioner knowledge of Co-60 and establish acceptable willingness-to-pay (WTP) thresholds for additional shielding requirements for use in future cost-benefit analysis. A nationwide survey of U.S. radiation oncologists was conducted from June to July 2015, assessing knowledge of HDR sources, brachytherapy unit shielding, and factors that may influence source-selection decision-making. Self-identified decision makers in radiotherapy equipment purchase and acquisition were asked their WTP on shielding should a more cost-effective source become available. Four hundred forty surveys were completed and included. Forty-four percent were ABS members. Twenty percent of respondents identified Co-60 as an HDR source. Respondents who identified Co-60 were significantly more likely to be ABS members, have attended a national brachytherapy conference, and be involved in brachytherapy selection. Sixty-six percent of self-identified decision makers stated that their facility would switch to a more cost-effective source than Ir-192, if available. Cost and experience were the most common reasons provided for not switching. The most common WTP value selected by respondents was <$25,000. A majority of respondents were unaware of Co-60 as a commercially available HDR source. This investigation was novel in directly assessing decision makers to establish WTP for shielding costs that source change to Co-60 may require. These results will be used to establish WTP threshold for future cost-benefit analysis. Copyright © 2017 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  6. SU-E-T-380: Evaluation of BEBIG HDR 60Co System for AccuBoost Therapy

    SciTech Connect

    Zehtabian, M; Sina, S; Rivard, M; Meigooni, A Soleimani

    2015-06-15

    Purpose: In this project, the possibility of utilizing the BEBIG 60Co HDR system for AccuBoostTM treatment has been evaluated. Methods: Dose distributions in various breast sizes have been calculated for both Co-60 and Ir-192 sources using the MCNP5 code. These calculations were performed in breast tissues with thicknesses of 4cm, 6cm, and 8cm. The initial calculations were performed with the same applicator dimensions as the existing applicators used with the HDR Ir-192 system. The activity of the Co-60 source was selected such that the dose at the breast center was the same as the values from 192Ir. Then, the applicator thicknesses were increased to twice of those used with HDR Ir-192 system, for reducing skin and chest doses by Co-60 system. Dose to breast skin and chest wall were compared for both applicators types, with and without inclusion of a focusing cone at the applicator center. Results: The results showed that loading HDR Co-60 source inside the thin applicators impose higher doses to breast skin and chest wall compared to the 192Ir source. The area of the chest wall covered by 10Gy when treated by Co-60 with the thin and thick applicators, or treated by Ir-192 with thin applicator are 79cm2, 39cm2, and 3.8cm2, respectively. These values are reduced to 34cm2, 0cm2, and 0cm2 by using the focusing cone. It is worth noting that the breast skin areas covered by the 60Gy isodose line are 9.9cm2 and 7.8cm2 for Co-60 with the thin and thick applicators, respectively, while it is 20cm2 for Ir-192 when no focusing cone is present. These values are 0cm2, 0cm2, and 11cm2 in the presence of the focusing cone. Conclusion: The results indicate that using Co-60 with the thicker applicators is beneficial because of the higher half-life of Co-60, and the reduced maximum skin dose when compared with Ir-192.

  7. 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.

  8. Investigation on Main Radiation Source at Operation Floor of Fukushima Daiichi Nuclear Power Station Unit 4

    NASA Astrophysics Data System (ADS)

    Hirayama, Hideo; Kondo, Kenjiro; Suzuki, Seishiro; Hamamoto, Shimpei; Iwanaga, Kohei

    2017-09-01

    Pulse height distributions were measured using a LaBr3 detector set in a 1 cm lead collimator to investigate main radiation source at the operation floor of Fukushima Daiichi Nuclear Power Station Unit 4. It was confirmed that main radiation source above the reactor well was Co-60 from the activated steam dryer in the DS pool (Dryer-Separator pool) and that at the standby area was Cs-134 and Cs-137 from contaminated buildings and debris at the lower floor. Full energy peak count rate of Co-60 was reduced about 1/3 by 12mm lead sheet placed on the floor of the fuel handling machine.

  9. 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.

  10. 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.

  11. [Influence of sterilization treatments on continuous carbon-fiber reinforced polyolefin composite].

    PubMed

    Guan, Shi-bing; Hou, Chun-lin; Chen, Ai-min; Zhang, Wei; Wang, Ji-e

    2007-08-21

    To evaluate the influence of sterilization treatment on continuous carbon-fiber reinforced polyolefin composite (CFRP) so as to provide experimental reference for selection of sterilization method for CFRP. Seventy bars of CFRP were divided into 7 equal groups to undergo sterilization by autoclave, 2% glutaraldehyde soaking, 75% alcohol soaking, ethylene oxide sterilization, and Co-60 gamma ray irradiation of the dosages 11 kGy, 25 kGy, and 18 kGy respectively, and another 10 bars were used as blank controls. Then the bars underwent three-point bending test and longitudinal compression test so as to measure the biomechanical changes after sterilization treatment, including the maximum load, ultimate strength, and elastic modulus. Three-point bending test showed that the levels of maximum load of the all experimental groups were lower than that of the control group, however, only those of the 3 Co-60 irradiation groups were significantly lower than that of the control group and that Co-60 radiation lowered the level of maximum load dose-dependently; and that the levels of ultimate strength of all the all experimental groups were lower than that of the control group, however, only those of the 3 Co-60 groups were significantly lower than that of the control group and that the higher the dosage of Co-60 radiation the lower the level of ultimate strength, however, not dose-dependently. The elastic modulus of the Co-60 25 KGy group was significantly higher than that of the control group, and there was no significant difference in the level of ultimate strength among the other groups. Longitudinal compression test showed that the levels of maximum load and ultimate strength of the 3 Co-60 irradiation groups, autoclave group, and circular ethylene groups were significantly lower than that of the control group, and there was no significant difference in elastic modulus among different groups. During sterilized package of CFRP products produced in quantity autoclave

  12. Proceedings of the Adaptive Sensor Array Processing (ASAP) Workshop 12-14 March 1997. Volume 1.

    DTIC Science & Technology

    2007-11-02

    PLH PQ Q H H £; S W Pu OH ?S c o -*—» 0...Q e <£ fc! C O «5 00 P-, CO PLH > OH’ Ö £ ^ > PH , < £ H CO > i—i Q CO CO H ’S H 2 •^ co &#60q O O CO...co > O H ° H PQ co v S5 r^ < P^ OH O pc^ PLH I—I O CO o IS CO H P < O co &#60 PL, en i—i o Q I—I o 1-3 o H H Ü EH

  13. 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…

  14. 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…

  15. 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…

  16. 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.

  17. Estudio Sobre Portadores Cronicos de Salmonellas en Manipuladores de Alimentos de la Ciudad de Iquitos (Study of Chronic Salmonella Carriers in Food Handlers in the City of Iquitos)

    DTIC Science & Technology

    1990-01-01

    manipuladores de alimentos en estudio. 779 (77.90%) fueron del sexo femcnino y 221 (22.10%) del sexo masculino. siendo el mayor porcentaje mujeres (234 - 30.04...papel de ios portadlores cr6- Woos en 460 mujeres dadas de alt. del hospital de Chile, encontrandose 34 porta- dores o sea 7.4 % excediindose las...4 sujetos 3.6 % portadores cr6nicos de Salmoncilas. 1S0 En Argentina 1974, se inves:,16 la frecuencia de Saiimoncilas en 146 manipulado- res de

  18. 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…

  19. Informe sobre el avance del proyecto de determinaciones de V sen i para todas las estrellas B más brillantes que 6.5 mag.

    NASA Astrophysics Data System (ADS)

    Abt, H.; Levato, H.

    Se ha finalizado con la determinación de V sen i para todas las estrellas B más brillantes que 6.5 mag y al norte de -30 grados de declinación. Esta muestra involucra casi 1000 estrellas. Las observaciones fueron realizadas desde KPNO. Mientras tanto, se ha completado desde CASLEO la observación de 350 estrellas B más brillantes que 6.5 mag. al sur de -30 grados. Además de la determinación de la rotación axial se determinan, en los casos posibles, los anchos equivalentes de las líneas 4471 Ådel He I y 4481 Ådel Mg II.

  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. 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…

  2. Memorias del tercer simposio internacional sobre economía, planificación, y políticas de los incendios forestales: problemas y enfoques comunes

    Treesearch

    Armando González-Cabán

    2009-01-01

    Estas memorias resumen el resultado de un simposio diseñado para discutir los problemas actuales que confrontan las agencias con responsabilidad para la proteccion contra incendios forestales a nivel federal y estadual en los EE.UU., al igual que agencias en la comunidad internacional. Los temas discutidos en el simposio incluyen economía del fuego, teoría y modelos...

  3. 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…

  4. 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.…

  5. Development and Initial Validation of a Questionnaire to Assess the Reading Beliefs of Undergraduate Students: The "Cuestionario de Creencias Sobre la Lectura"

    ERIC Educational Resources Information Center

    Lordán, Eva; Solé, Isabel; Beltran, Francesc S.

    2017-01-01

    The aim of this research was to develop a new questionnaire for exploring the reading beliefs of undergraduate students, because the only currently available instrument has conceptual and methodological limitations. The paper describes the process of developing the instrument and presents a range of psychometric data obtained from a sample of 558…

  6. 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…

  7. 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…

  8. 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…

  9. 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.

  10. Sobre la posible existencia de un bulbo o núcleo de población II en la Nube Mayor de Magallanes

    NASA Astrophysics Data System (ADS)

    Clariá, J. J.; Dutra, D. M.; Bica, E.; Piatti, A. E.

    Based on recent results obtained with the Hubble Space Telescope, we present a census of genuine globular clusters in the Large Magellanic Cloud (LMC) and we examine their spatial distribution. Spectroscopic observations carried out at Complejo Astronómico El Leoncito (CASLEO, Argentina) allow us to add two new clusters (NGC 1928 and NGC 1939) to the list of genuine LMC globular clusters. We present evidence that old clusters projected on the LMC bar region may constitute a population II core, probably reminiscent of an ancient bulge, which together with a central disc could have evolved into the observed LMC bar by SMC and/or Galaxy interactions. A detailed discussion was given in MNRAS 305, 373 (1999).

  11. "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)

  12. 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…

  13. 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.

  14. 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…

  15. 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…

  16. 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…

  17. 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…

  18. 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…

  19. 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.

  20. Investigación observacional sobre el papel de las estrellas binarias en la ecología de cúmulos estelares

    NASA Astrophysics Data System (ADS)

    González, J. F.; Levato, H.; Grosso, M.

    We present preliminary results of a long-term project devoted to the observational study of the binary star population in open clusters and its connection with the dynamical and evolutionary properties of the clusters. We report the discovery of 17 double-lined spectroscopic binaries, 30 radial velocity variables and about 30 suspected variables. In the 17 clusters of our sample the binary frequency ranges between 20 and 40 %, and reaches typically 60 % if all suspected binaries are included. We study the spatial distribution of the binary stars with respect to the cluster center and we discuss the statistical correlation of the mass-ratio distribution with the cluster age.

  1. 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…

  2. 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…

  3. Nuevos resultados sobre la cinemática global y nuclear de NGC 253: movimientos no circulares y emisión en Br γ

    NASA Astrophysics Data System (ADS)

    Camperi, J. A.; Gunthardt, G. I.; Díaz, R. J.; Agüuero, M. P.; Gimeno, G.; Pessev, P.

    Continuing with previous research (Camperi et al., BAAA, 54, 377, 2011), new heliocentric radial velocity distributions are presented for the nearby galaxy NGC 253, obtained from the ionized hydrogen recombination line Hα. These distributions have been derived from long-slit spectroscopy for various position angles. It is also shown the heliocentric radial velocity distribution corresponding to part of the infrared data (ionized hydrogen recombination line Brγ) observed with the Phoenix spectrograph of the Gemini South Observatory. Sequential mapping with the long slit using this instrument will enable to study in detail the kinematics of the galaxy's core, which is strongly obscured by dust. FULL TEXT IN SPANISH

  4. 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…

  5. 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…

  6. Otra perspectiva sobre lo que los ninos deben estar aprendiendo (Another Look at What Young Children Should Be Learning). ERIC Digest.

    ERIC Educational Resources Information Center

    Katz, Lilian G.

    This Spanish-language ERIC Digest addresses the question of what young children should be learning that will best serve their development and learning in the long term. Two major dimensions of development--normative and dynamic--are explored, and four categories of learning goals are discussed: (1) knowledge; (2) skills; (3) dispositions; and (4)…

  7. 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…

  8. 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,…

  9. 8 de noviembre de 2006: Mercurio pasea sobre el disco solar (Micro eclipse anular de Sol o el segundo tránsito de Mercurio del siglo XXI)

    NASA Astrophysics Data System (ADS)

    Mallamaci, C. C.

    On Wendsday November 8, 2006, the second transit of Mercury over the Sun of the 21st. Century, took place. In this work we present the principal characteristics of the phenomenon ocurrence, the visibility region and the local circumstances for some locations of Argentina and other countries of the world. Full TEXT IN SPANISH

  10. 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.…

  11. Lo Que los Padres y los Maestros Deberian Saber sobre la...Aceleraction (What Parents and Teachers Should Know about Academic Acceleration).

    ERIC Educational Resources Information Center

    Guenther, Alex

    Designed for Spanish-speaking educators and parents, this pamphlet discusses academic acceleration for gifted children. Major types of academic acceleration and their benefits are described. These include: (1) early admission to kindergarten that saves parents of gifted children the expenses of a year of preschool, allows children to be…

  12. 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,…

  13. 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,…

  14. 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.

  15. 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.

  16. 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…

  17. 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…

  18. Conservation Plan for the Cerulean Warbler on its nonbreeding range - Plan de conservación para la Reinita Cerúlea sobre su rango no reproductivo

    Treesearch

    Paula Caycedo; Paul Hamel; Melinda Welton; David Caro; D. Wiedenfield

    2010-01-01

    This plan was prepared by Paula Caycedo on behalf of American Bird Conservancy and Fundación ProAves with the editorial and technical assistance of Paul Hamel, Melinda Welton, David Caro, David Wiedenfeld, David Mehlman, Deanna Dawson, Katie Fallon, and Paul Salaman. Additional support was provided by the Neotropical Migratory Bird Conservation Act of the U.S. Fish and...

  19. 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)

  20. Sistema de cúmulos globulares de la galaxia lenticular NGC 6861: en busca de indicios sobre la formación de las S0s.

    NASA Astrophysics Data System (ADS)

    Escudero, C. G.; Faifer, F. R.; Bassino, L. P.; Calderón, J. P.; Caso, J. P.

    We present a preliminar photometric study of the globular cluster system (GCS), associated to the lenticular galaxy (S0) NGC 6861, which is located in a low density environment (d˜31.8 Mpc). It is based on GEMINI/GMOS images (GS-2010B-Q-2: PI Lilia P. Bassino) in the filters g', r', i' of three fields, one of them centered in the galaxy. We find a large number of GCs candidates and detect the presence of at least two sub-populations of GCs (``blue''/metal-poor and ``red''/metal-rich). The spatial distribution of ``red'' candidates presents a higher concentration toward the galaxy (associated to the bulge?), while the distribution of ``blue'' candidates is more homogeneus over the three fields (associated to the halo?). In the color-magnitud diagram, the ``blue'' GC candidates show a possible mass-luminosity relation, known as ``blue-tilt'', probably detected for the first time in a lenticular galaxy. FULL TEXT IN SPANISH

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

    USDA-ARS?s Scientific Manuscript database

    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...

  2. 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…

  3. 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…

  4. Drug-eluting stent thrombosis: results from the multicenter Spanish registry ESTROFA (Estudio ESpañol sobre TROmbosis de stents FArmacoactivos).

    PubMed

    de la Torre-Hernández, José M; Alfonso, Fernando; Hernández, Felipe; Elizaga, Jaime; Sanmartin, Marcelo; Pinar, Eduardo; Lozano, Iñigo; Vazquez, Jose M; Botas, Javier; Perez de Prado, Armando; Hernández, Jose M; Sanchis, Juan; Nodar, Juan M Ruiz; Gomez-Jaume, Alfredo; Larman, Mariano; Diarte, Jose A; Rodríguez-Collado, Javier; Rumoroso, Jose R; Lopez-Minguez, Jose R; Mauri, Josepa

    2008-03-11

    This study sought to assess the incidence, predictors, and outcome of drug-eluting stent(DES) thrombosis in real-world clinical practice. The DES thromboses in randomized trials could not be comparable to those observed in clinical practice, frequently including off-label indications. We designed a large-scale, nonindustry-linked multicentered registry, with 20 centers in Spain. The participant centers provided follow-up data for their patients treated with DES, reporting a detailed standardized form in the event of any angiography-documented DES-associated thrombosis occurring. Of 23,500 patients treated with DES, definite stent thrombosis(ST) developed in 301: 24 acute, 125 subacute, and 152 late. Of the late, 62 occurred >1 year(very late ST). The cumulative incidence was 2% at 3 years. Antiplatelet treatment had been discontinued in 95 cases(31.6%). No differences in incidences were found among stent types. Independent predictors for subacute ST analyzed in a subgroup of 14,120 cases were diabetes, renal failure, acute coronary syndrome, ST-segment elevation myocardial infarction, stent length, and left anterior descending artery stenting, and for late ST were ST-segment elevation myocardial infarction, stenting in left anterior descending artery, and stent length. Mortality at 1-year follow-up was 16% and ST recurrence 4.6%. Older age, left ventricular ejection fraction <45%, nonrestoration of Thrombolysis In Myocardial Infarction flow grade 3, and additional stenting were independent predictors for mortality. The cumulative incidence of ST after DES implantation was 2% at 3 years. No differences were found among stent types. Patient profiles differed between early and late ST. Short-term prognosis is poor, especially when restoration of normal flow fails.

  5. 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…

  6. 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…

  7. 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…

  8. 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)

  9. Development and Initial Validation of a Questionnaire to Assess the Reading Beliefs of Undergraduate Students: The "Cuestionario de Creencias Sobre la Lectura"

    ERIC Educational Resources Information Center

    Lordán, Eva; Solé, Isabel; Beltran, Francesc S.

    2017-01-01

    The aim of this research was to develop a new questionnaire for exploring the reading beliefs of undergraduate students, because the only currently available instrument has conceptual and methodological limitations. The paper describes the process of developing the instrument and presents a range of psychometric data obtained from a sample of 558…

  10. 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)

  11. 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

  12. 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)

  13. 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.

  14. 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…

  15. 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

  16. 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…

  17. 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…

  18. 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.

  19. 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.

  20. Radionuclides behavior in melting process and its products of non-combustible solid waste by induction heat melting

    SciTech Connect

    Obata, M.; Teshima, T.; Kanagawa, Y.; Hirata, Y.; Karigome, S.; Akagawa, Y.

    1995-12-31

    In Japan, the second stage burial plan is under consideration, and this plan will mainly aim to bury non-combustible low level radioactive wastes. Candidate treatment methods are a direct cement solidification method, a compacting method, and a melting method. The authors examined the residual fraction of radionuclides, such as Cs-134 (instead of Cs-137), Co-60, Sr-85 (instead of Sr-90), at typical melting conditions for non-combustible waste at laboratory scale tests and mock-up scale tests. The authors also examined the distribution behavior of these nuclides, because melted products of non-combustible waste have a structure of the pile of one ceramic layer and one metal layer. Volatilized Co-60 and Sr-85 was not detected and approximately all the amount of Co-60 and Sr-85 was collected in melted products. Residual fraction of Cs-134 was in the range of 50 to 90% at laboratory scale tests, and about 50% at mock-up scale tests. For the distribution behavior, Co-60 was not detected in a ceramic layer, and Cs-134 and Sr-85 were not detected in a metal layer.

  1. Gamma-Radiation-Induced Degradation of Actively Pumped Single-Mode Ytterbium-Doped Optical Laser - Postprint

    DTIC Science & Technology

    2015-01-01

    following day , 20 hours later. The fiber was then lowered back into the Co-60 cell and again exposed to 150 krad(Si). The second fiber was unpumped...Schneider, Kelly Simmons-Potter, William J. Thomes, Jr., Dorothy C. Meister, Ray P. Bambha, and Dahv A. V. Kliner, “Spectrally Resolved Transmission

  2. 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.

  3. Teratogenic effect of californium-252 irradiation in rats.

    PubMed

    Satow, Y; Lee, J Y; Hori, H; Okuda, H; Tsuchimoto, S; Sawada, S; Yokoro, K

    1989-06-01

    The teratogenicity of californium-252 (Cf-252) irradiation which generates approximately 70% 2.3 MeV fast neutron and 30% gamma rays was evaluated. A single whole body exposure of Cf-252 at various doses was given to pregnant rats on day 8 or 9 of pregnancy, followed by microscopic autopsy of the fetuses at the terminal stage of pregnancy to search for external and internal malformations. For comparison, pregnant rats were irradiated with various doses of cobalt-60 (Co-60) standard gamma rays at the same dose rate (1 rad/min.). The doses were 20-120 rad of Cf-252 and 80-220 rad of Co-60. Using frequency of radiation induced malformations observed on day 8 of pregnancy as an index, relative biological effectiveness (RBE) of 2.3-2.7 was obtained from the straight line obtained by modifying by the least squares method the frequency curves of malformed fetuses in total implants and in surviving fetuses. The types of malformations induced by Cf-252 and Co-60 irradiation were alike. Using fetal LD50 as an index, 2.4 was obtained as RBE when irradiated on day 8 of pregnancy and 3.1 as that when irradiated on day 9. The results showed that Cf-252 had stronger a teratogenic effect than Co-60 gamma rays.

  4. Radiological survey of San Diego Bay

    SciTech Connect

    Semler, M.O.; Blanchard, R.L.

    1989-06-01

    A radiological survey of three sites in San Diego Bay provided the basis for the following conclusions: 1. Small quantities of Co-60 (0.02-0.05 pCi/g) are present in the bottom sediments in some areas of the harbor at the Submarine Base. Most, if not all, of the Co-60 contamination present probably originated prior to the earlier 1967 survey that reported Co-60 levels as much as 300 times larger than those observed in this study. The highest Co-60 concentration measured is now less than one percent of the normal background radioactivity in harbor sediment samples. 2. No tritium or gamma-ray emitters, other than trace amounts of those occurring naturally, were detected in surface water from the dock areas or in nearby drinking water supplies. 3. Only radionuclides of natural origin and trace amounts of Cs-137 from fallout of previous nuclear weapons tests were detected in samples of kelp, algae, and fish taken from the harbor at the Submarine Base. 4. Gamma-ray surveys of the harbors near the docking areas and along shorelines and beaches near the shipyards failed to detect any exposure rates above background. 3 refs., 4 figs., 3 tabs.

  5. 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.

  6. Ferromagnetic resonance in 80NiFe/Cu/Co multilayer films

    NASA Astrophysics Data System (ADS)

    Koizumi, H.; Ando, Y.; Miyazaki, T.

    1996-12-01

    Trilayers and multilayers containing ferromagnetic 80NiFe,Co layers separated by nonmagnetic Cu layers were fabricated using the magnetron sputtering method. For 80NiFe(60 Å)/Cu (d Cu)/ Co(60 Å) trilayer films, the MR ratio and the exchange coupling strength oscillated with increasing dCu. For 80NiFe(60 Å)/Cu (d Cu)/ Co(60 Å)/Cu (d Cu)/ 80NiFe(60 Å) multilayer films, however, the exchange coupling between the bottom 80NiFe and the Co layers oscillated, while that between the Co and the top 80NiFe layers decreased monotonously with increasing dCu. Consequently, antiferromagnetic exchange coupling was not achieved between the Co(60 Å) and the top magnetic layer. The reason for the nonexistence of antiferromagnetic exchange coupling is discussed by taking into account the rougher surface of the Co(60 Å) layer caused by the growth of the different crystalline structures.

  7. [Induced radioactivity in irradiated foods by X ray or gamma ray].

    PubMed

    Miyahara, Makoto

    2007-01-01

    In the course of the archival studies on safety of irradiated foods by the US Army, experimental records conducted by Glass & Smith, and Kruger & Wilson were investigated, based on our experimental experience. Food irradiation by Co-60 or 4 approximately 24MeV X ray can induce small amount of radioactivity in the foods. The principal mechanisms of the nuclear reactions are (gamma, n). The resulting nuclear products found in irradiated target solutions were Ba-135m, Pb-204m, Hg-199m, Ag-107m,Ag-109m, Cd-111m,Cd-113m, Sn-117m, Sn-119m, Sr-87m, Nb-93m, In113m, In-115m, Te-123m, Te-125m, Lu-178m Hf-160m by the (gamma, n) reaction. The total radio-activities in beef, bacon, shrimp, chicken, and green beans were counted at 60 days after irradiation by Cs-137, Co-60, and fuel element. The activities more than background were found in irradiated bacon and beef by Co-60. and activities were found in most foods when foods were irradiated by high energy X ray and the fuel element. The results were understood as the neutron activation by (gamma, n) or (n, gamma) reaction. Therefore, high energy X ray and spent fuel element were not used for food irradiation. As the results of this study Co-60 has been used with small amount of induced radioactivity in food.

  8. Sensitivity of LDEF foil analyses using ultra-low background germanium versus large NaI(T1) multidimensional spectrometers

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    Cobalt samples were analyzed for cosmic ray induced Co-60 with both an ultralow background germanium gamma ray spectrometer and with a large NaI(T1) multidimensional spectrometer using electronic anticoincidence shielding. Aluminum samples were analyzed for Na-22. The results are presented along with the relative sensitivities and precision afforded by the two methods.

  9. FFTF (Fast Flux Test Facility) cobalt test assembly results

    SciTech Connect

    Rawlins, J.A.; Wootan, D.W.; Carter, L.L.; Brager, H.R.; Schenter, R.E.

    1987-10-01

    A cobalt test assembly containing yttrium hydride pins for neutron moderation was irradiated in the Fast Flux Test Facility during Cycle 9A for 137.7 equivalent full power days at a power level of 291 MW. The 36 test pins consisted of a batch of 32 pins containing cobalt metal to produce Co-60, and a set of 4 pins with europium oxide to produce Gd-153, a radioisotope used in detection of the bone disease Osteoporosis. Post-irradiation examination of the cobalt pins determined the Co-60 produced with an accuracy of about 5%. The measured Co-60 spatially distributed concentrations were within 20% of the calculated concentrations. The assembly average Co-60 measured activity was 4% less than the calculated value. The europium oxide pins were gamma scanned for the europium isotopes Eu-152 and Eu-154 to an absolute accuracy of about 10%. The measured europium radioisotope and Gd-153 concentrations were within 20% of calculated values. In conclusion, the hydride assembly performed well and is an excellent vehicle for many Fast Flux Test Facility isotope production applications. The results also demonstrate that the calculational methods developed by the Westinghouse Hanford Company are very accurate. 4 refs., 3 figs., 1 tab.

  10. ALARA efforts in nordic BWRs

    SciTech Connect

    Ingemansson, T.; Lundgren, K.; Elkert, J.

    1995-03-01

    Some ALARA-related ABB Atom projects are currently under investigation. One of the projects has been ordered by the Swedish Radiation Protection Institute, and two others by the Nordic BWR utilities. The ultimate objective of the projects is to identify and develop methods to significantly decrease the future exposure levels in the Nordic BWRS. As 85% to 90% of the gamma radiation field in the Nordic BWRs originates from Co-60, the only way to significantly decrease the radiation doses is to effect Co and Co-60. The strategy to do this is to map the Co sources and estimate the source strength of Co from these sources, and to study the possibility to affect the release of Co-60 from the core surfaces and the uptake on system surfaces. Preliminary results indicate that corrosion/erosion of a relatively small number of Stellite-coated valves and/or dust from grinding of Stellite valves may significantly contribute to the Co input to the reactors. This can be seen from a high measured Co/Ni ratio in the feedwater and in the reactor water. If stainless steel is the only source of Co, the Co/Ni ratio would be less than 0.02 as the Co content in the steel is less than 0.2%. The Co/Ni ratio in the reactor water, however, is higher than 0.1, indicating that the major fraction of the Co originates from Stellite-coated valves. There are also other possible explanations for an increase of the radiation fields. The Co-60 inventory on the core surfaces increases approximately as the square of the burn-up level. If the burn-up is increased from 35 to 5 MWd/kgU, the Co-60 inventory on the core surfaces will be doubled. Also the effect on the behavior of Co-60 of different water chemistry and materials conditions is being investigated. Examples of areas studied are Fe and Zn injection, pH-control, and different forms of surface pre-treatments.

  11. 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

  12. Magnetic Pinning and Coupling of Magnetic Nanoantidot Arrays

    NASA Astrophysics Data System (ADS)

    Kranov, Yanko; McIlroy, David; Dowben, Peter; Cheng, Ruihua; Justus, B. L.; Rosenberg, A.

    2003-03-01

    Nanoscale antidote arrays ranging in size from 362 nm down to 100 nm were grown by MBE. The antidot arrays consisted of Co60Å/Ni90Å/Co60Å deposited on nanochannel glass. The collective magnetic properties of the antidot arrays were obtained by super conducting quantum interference device (SQUID) magnetometry. The magnetic domain structure of the arrays were imaged by MFM. It was found that these arrays present well defined regions with remanence, forming two prevailing types of domain organizations: Isolated domains and Stripe-like pattern (linked domains). The artificial patterning produces pinning sites, thereby facilitating the formation of well-ordered magnetic domains. The observed domain structures are consistent with the finite element modelling of the antidot arrays. This work is supported by ONR (N00014-02-1-0925)

  13. 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.

  14. Comparison of yields of stable perfluoroalkyl radicals in gamma and neutron radiolysis

    SciTech Connect

    Allayarov, S.R.; Barkalov, I.M.; Gol'danskii, V.I.; Zuev, A.P.

    1985-09-01

    In the irradiation of liquid perfluoro-1-methyl-4-isoburylcyclohexane (MBC) with Co-60 gamma rays, stable perfluoroalkyl radicals are formed. This paper shows the dependence on dose of the concentration of stable radicals formed during the irradiation of MBC with Co-60 gamma rays at 300 degrees K. The EPR spectra of these radicals show a doublet and a triplet with splitting at 3.9 and 5.6 mT, respectively. On the basis of perfluoro compounds like MBC it is possible to create dosimetric systems with which the dose of gamma-irradiation can be determined against a background stream of fast neutrons, simply by measuring the concentration of stabilized radicals.

  15. Environmental radionuclide concentrations in the vicinity of the calvert cliffs nuclear power plant: 1985-1986. Final report

    SciTech Connect

    Domotor, S.L.; McLean, R.I.

    1988-11-01

    High-resolution gamma spectroscopy was used to determine radionuclide concentrations in sediment, finfish, shellfish, and aquatic vegetation collected from the Chesapeake Bay in the vicinity of the Calvert Cliffs Nuclear Power Plant (CCNPP) during 1985-1986. Low concentrations of radionuclides attributable to CCNPP (Ag-110m, Co-58, Co-60, and Zn-65) were detected in all biota (except edible finfish) and in sediments. Silver-110m was the principal CCNPP-related radionuclide detected in biota (particularly oysters); Co-58 and Co-60 were the principal CCNPP-related radionuclides detected in sediments. CCNPP-related radionuclide concentrations detected in Bay biota and sediments were within ranges observed in previous years and represent small increments to radionuclide concentrations in the Bay relative to natural and weapons test levels.

  16. Technical Basis Document for the GR-460, Contamination Monitoring System

    DTIC Science & Technology

    2006-12-01

    background uranium, thorium, and radium ; values as high as 6a might need to be used. The GPS will not work indoors. GAMMA ENERGY CORRELATION The system...137 661.6 115 0.26 keV Co-60 1173.2 200 -1.08 keV Co-60 1332.5 226 -2.87 keV Eu-152 1408 239 0.64 keV Th-208 (Th-232) 2614.7 435 5.61 keV Equation...309 4 226 305 359 393 383 382 384 335 326 259 3 174 225 256 274 275 282 274 283 238 194 2 125 144 170 405 399 382 181 167 153 132 1 74 91 99 107 111

  17. 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.

  18. Reliability studies on NPN RF power transistors under swift heavy ion irradiation

    NASA Astrophysics Data System (ADS)

    Pushpa, N.; Praveen, K. C.; Gnana Prakash, A. P.; Naik, P. S.; Cressler, John D.; Gupta, S. K.; Revannasiddaiah, D.

    2012-02-01

    NPN RF power transistors were irradiated with 140 MeV Si 10+ ions, 100 MeV F 8+ ions, 50 MeV Li 3+ ions and Co-60 gamma radiation in the dose range from 100 krad to 100 Mrad. The transistor characteristics are studied before and after irradiation from which the parameters such as Gummel characteristics, excess base current (Δ IB = IBpost - IBpre), dc current gain ( hFE), transconductance ( gm) and collector-saturation current ( ICSat) are determined. The degradation observed in the electrical characteristics is almost the same for different types of ion irradiated NPN RF power transistors with similar total doses although there is a large difference in the linear energy transfer (LET) of the ions. Further, it was observed more degradation in DC I- V characteristics of ion irradiated devices than the Co-60 gamma irradiated devices for higher doses.

  19. Some Characteristics of the Resistance Transfer Factor (RTF) Episome as Determined by Inactivation with Tritium, P32, and Gamma Radiation

    PubMed Central

    Painter, Robert B.; Ginoza, Herbert S.

    1966-01-01

    The resistance transfer factor (RTF) episome was studied by measuring its inactivation by Co60 gamma radiation, by incorporated P32, and by tritium incorporated as tritium-labeled thymine. The D37 for Co60 irradiation was 7 to 9 × 104 rad. Growth of the bacteria harboring the RTF in BUdR (bromouracil deoxyriboside) increased the sensitivity of the RTF to the gamma radiation. The RTF was markedly inactivated by tritium after growth of the host (thymine requiring) bacteria in tritium-labeled thymine, thus further establishing the presence of thymine in the genome of the RTF. Assuming the efficiency of inactivation by P32 to be 10%, the phosphorus content of the RTF was estimated to be about 2 × 105 P atoms/episome. The data suggest the RTF contains double stranded DNA with a molecular weight of the order of 3 to 8 × 107. PMID:5335449

  20. 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.

  1. Structure Shielding against Fallout Radiation from Nuclear Weapons

    DTIC Science & Technology

    1962-06-01

    fragment is initially formed, it will not enter into chemical combination. The Xenon quickly (in a few seconds) disintegrates to produce Cesium , which is...114 FIGURE B32. Cs-237, concrete. 115 FIGURE B33. Co-60, H2O. 116 10" ■m Iffi [l[g;— ^ - i Jjlp --^ SFr ^^ "r-C I li IJIPIIgiM lO

  2. Real Time Fault Detection and Diagnostics Using FPGA-Based Architectures

    DTIC Science & Technology

    2010-03-01

    latch-up (SEL) or the burnout (SEB). Another source of SEEs is impurities in the device material. There might be traces of uranium or thorium ...State University (OSU) Nuclear Reactor Lab (NRL) in Columbus, Ohio provided a Co-60 source. A simplified diagram showing the gamma irradiator can...board, controller board, and the remaining devices stayed fifteen feet above the reactor . Figure 29 depicts the entire set up used for the gamma

  3. Olive bagasse and nutshell as gamma shielding material

    NASA Astrophysics Data System (ADS)

    Inaç, Esra; Baytaş, A. Filiz

    2013-12-01

    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.

  4. 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.

  5. Gamma radiation induced resistivity changes in Iron

    NASA Astrophysics Data System (ADS)

    Tundwal, Ambika; Kumar, V.; Datta, A.

    2017-03-01

    Monte Carlo Code JA-IPU is used for estimation of Frenkel pairs and their effect on change of resistivity of Iron on irradiation by gamma spectrum of Co60. The Code includes three cascade processes of incident gamma, produced electrons and recoiled atoms and simulation of the lattice structure of the target material. Change in experimentally measured resistivity of Iron is found to vary with number of Frenkel pairs as (x - 1) ln N d .

  6. Extended- and Point-Source Radiometric Program

    DTIC Science & Technology

    1962-08-08

    Radiometric Measurements of Cs1 37 Sources Made with NaI Detector. . 60 6.2 Aerial Radiometric Measurements of Co 60 Sources Made with Bioplastic ...Hanford aircraft consisted of an NaI scintillator, bioplastic scintillator, and a 40-liter ionization chamber. The aircraft employed was a twin-engine...supply, amplifier, and count rate, was transistorized portable equipment designed and fabricated at Hanford. The bioplastic instrument consisted of a 5

  7. Dose Rate and Total Dose Radiation Testing of the Texas Instruments TMS320C30 32-Bit Floating Point Digital Signal Processor.

    DTIC Science & Technology

    1991-08-01

    curies. The radiation exposure rate is determined by the distance of the exposed specimens from the Co-60 source. 4.2 DOSE RATE TESTING We tested the... exposure . The test fixture monitored the internal registers and memory locations of the device while being exposed to subsequently higher dose rates. An...instrument measures the dose rate of the radiation exposure . Calibration of the dosimetry system is accomplished using thermoluminescent dosimeters (TLDs

  8. 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.

  9. Cosmogenic radionuclides and noble gases in the Wethersfield (1982) chondrite

    NASA Technical Reports Server (NTRS)

    Evans, J. C.; Reeves, J. H.; Bogard, D. D.

    1986-01-01

    The Wethersfield (1982) chondrite was assayed for a suite of cosmogenic radionuclides shortly after fall. Data are reported for Be-7, Na-22, All-26, Sc-46, V-48, Cr-51, Mn-54, Co-56, Co-57, and Co-60. A comparison is made with predicted results based on a scaling to the Deep River Neutron Monitor. Noble gases were also assayed in a subsample. The cosmic-ray-exposure age is estimated to be 45 Myr.

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

    SciTech Connect

    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.

  11. Proposed definitions for isodose flatness and symmetry in clinical radiotherapy beams.

    PubMed

    Galiano, Eduardo; Joly, Tara; Wiebe, Federico

    2004-12-01

    In clinical radiotherapy it is important that beam intensity be as homogeneous as possible to reduce the probability of treatment failure. As an extension of the well established concepts of beam flatness and symmetry for characterizing radiotherapy beams, the concepts of isodose flatness and symmetry are introduced. The definitions are tested with actual data obtained from a Co-60 unit and a linear accelerator and results are presented. The concepts as defined appear to provide a useful quantitative indication of beam homogeneity.

  12. Speech Recognition: Acoustic, Phonetic and Lexical

    DTIC Science & Technology

    1985-10-01

    sffl^ss^t-iftsasisiiBiSiBa :.%^v 00 o o o CO &#60 I Q < "END-OF-FISCAL YEAR" REPORT Speech Recognition; Acoustic, Phonetic and Lexical...Virginia 22217 10. SOURCg OP PUNOINO NQS. PROGRAM I Li MINT NO. 1. TITUS Inciua* itcnniy dauifltaiuuii Speech Recognition; Acoustic, Phonetic and...34 Letter 1. Contract Information (a) Title: Speech Recognition: Acoustic, Phonetic , and Lexical Knowledge Representation (b) ONR Contract No.: N00014

  13. OPERATIONS TOGGLE, ARBOR and BEDROCK Events: DIAMOND SCULLS, DIDO QUEEN, HUSKY ACE, MING BLADE, HYBLA FAIR and DINING CAR, 20 July 1972 - 5 April 1975

    DTIC Science & Technology

    1987-11-30

    58m co 58 Co 60 iOpp8r ( 29 ) . . . . . . . . . . . . . Cu 64 Curium (96, . . . . . . . . . . . . . Cm 242 Cm 243 Cm 244 Cm 245 Cm 246...was conducted in the LOS pipe. 242 On 12 April (D+7), miners continued to prepare the tunnel for experiment recovery. Work also continued in...Pt 191 Pt 193m Pt 197m Pt 197 Plutonium (94) . . . . . . . . . . Pu 236 Pu 239 Pu 240 Pu 241 Pu 242 Polonium (84

  14. 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.

  15. Dielectric Spectroscopy of Semiconductors: Interpretation of the Frequency Response of Trapping Processes in Semiconductors.

    DTIC Science & Technology

    1987-12-01

    Semiconductor Statistics , Pergamon, Oxford, 1962 21. H J Queisser, Phys Rev Letters 54, 234 (1985) 22. L A Dissado and R M Hill, Non-exponential... SEMICONDUCTORS FILE CO &#60 INTERPRETATION OF THE FREQUENCY I RESPONSE OF TRAPPING PROCESSES CIN SEMICONDUCTORS SECOND PROGRESS REPORT ON CONTRACT DAJA 45-87-C...trapping proceses measured by the technique of Dielectric Spectroscopy of Semiconductors (DSS) reveals a ubiquitous and not generally recognised tendency

  16. Environmental Radioactivity in Denmark in 1986

    DTIC Science & Technology

    1988-11-01

    The marine environments at Barsebk and Ringhals were monitored for 137Cs and corrosion products (58Co 60Co, 652n, 54Mn). The Chernobyl accident caused a...and radiocesium in Danish cheese............................ 129 5.2.4. Iodine-131 in Danish milk after Chernobyl .......................... 130 5.3...and Lanqeland Belt areas ........... 214 8.6. The Baltic island, Bornholm ................... 216 8.7. Estimatinq the external dose from Chernobyl

  17. 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.…

  18. 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…

  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. 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 study…

  1. 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…

  2. 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…

  3. 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…

  4. 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

  5. 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…

  6. 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…

  7. 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…

  8. [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.

  9. 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…

  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. 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…

  12. Ten Facts Every Parent Should Know about the No Child Left Behind Act = Diez datos que cada padre debe saber sobre La Ley. Que Ningun Nino Se Quede Atras.

    ERIC Educational Resources Information Center

    Department of Education, Washington, DC.

    The No Child Left Behind Act (NCLB) is President George W. Bush's education reform law passed by Republicans and Democrats in Congress. This flier, in both English and Spanish, details 10 facts concerning NCLB to inform parents as to the goals of the Act and how they will affect their child's school. The flier highlights how the Act: (1) gives…

  13. 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…

  14. 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.…

  15. 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…

  16. 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…

  17. 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…

  18. 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…

  19. 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…

  20. Ten Facts Every Parent Should Know about the No Child Left Behind Act = Diez datos que cada padre debe saber sobre La Ley. Que Ningun Nino Se Quede Atras.

    ERIC Educational Resources Information Center

    Department of Education, Washington, DC.

    The No Child Left Behind Act (NCLB) is President George W. Bush's education reform law passed by Republicans and Democrats in Congress. This flier, in both English and Spanish, details 10 facts concerning NCLB to inform parents as to the goals of the Act and how they will affect their child's school. The flier highlights how the Act: (1) gives…

  1. 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…

  2. 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…

  3. 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…

  4. 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…

  5. 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…

  6. 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.

  7. 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…

  8. 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…

  9. 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…

  10. Todo Alumno: Un Manual de Recursos de PEER sobre Educacion Basada en Normas y Alumnos con Discapacidades (Every Single Student: A PEER Resource Manual on Standards-Based Education and Students with Disabilities).

    ERIC Educational Resources Information Center

    Landau, Julia K., Ed.; Romano, Carolyn A., Ed.; Vohs, Janet R., Ed.

    This manual in Spanish covers thirteen different topics relevant to the education of students with disabilities in the era of educational reform and standards-based education. Sections include: (1) "Raising Standards of Learning: Standards-Based Education and Students with Disabilities" (Janet R. Vohs, Julia K. Landau, and Carolyn…

  11. 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…

  12. 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…

  13. 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…

  14. 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 District in…

  15. 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…

  16. 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…

  17. Relatorio Final Sobre o Ensino Bilingue: Resultados da Avaliacao Externa da Experiencia de Escolarizacao Bilingue em Mocambique (PEBIMO) (Final Report on Bilingual Education: Results of External Evaluation of an Experiment in Bilingual Education in Mozambique).

    ERIC Educational Resources Information Center

    Benson, Carolyn J.

    The PEBIMO project was designed to determine whether bilingual education could improve the quality of primary education in Mozambique, recognizing that Portuguese is not the native language of the majority of Mozambican students. The project began in 1992 with 8 cohorts of first grade in 2 provinces; during this investigation, students were in…

  18. 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.

    USDA-ARS?s Scientific Manuscript database

    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...

  19. 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…

  20. 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…

  1. Thrombosis of second-generation drug-eluting stents in real practice results from the multicenter Spanish registry ESTROFA-2 (Estudio Español Sobre Trombosis de Stents Farmacoactivos de Segunda Generacion-2).

    PubMed

    de la Torre Hernández, José M; Alfonso, Fernando; Gimeno, Federico; Diarte, Jose A; Lopez-Palop, Ramón; Pérez de Prado, Armando; Rivero, Fernando; Sanchis, Juan; Larman, Mariano; Diaz, Jose F; Elizaga, Jaime; Moreiras, Javier Martín; Gomez Jaume, Alfredo; Hernández, José M; Mauri, Josepa; Recalde, Angel Sánchez; Bullones, Juan A; Rumoroso, Jose R; Del Blanco, Bruno García; Baz, Jose A; Bosa, Francisco; Botas, Javier; Hernández, Felipe

    2010-09-01

    This study sought to evaluate second-generation drug-eluting stent (DES) thrombosis in clinical practice. First-generation DES are associated with a significant incidence of late thrombosis. There is paucity of data regarding real practice late thrombosis incidence and predictors with second-generation DES, zotarolimus-eluting stent (ZES), and everolimus-eluting stents (EES). A prospective, large-scale, non-industry-linked multicenter registry was designed. Complete clinical-procedural data and systematic follow-up of all patients treated with these stents was reported in a dedicated registry supported by the Spanish Working Group on Interventional Cardiology. From 2005 to 2008, 4,768 patients were included in 34 centers: 2,549 treated with ZES, and 2,219 with EES. The cumulative incidence of definite/probable thrombosis for ZES was 1.3% at 1 year and 1.7% at 2 years and for EES 1.4% at 1 year and 1.7% at 2 years (p = 0.8). The increment of definite thrombosis between the first and second year was 0.2% and 0.25%, respectively. In a propensity score analysis, the incidence remained very similar. Ejection fraction (adjusted hazard ratio [HR]: 0.97; 95% confidence interval [CI]: 0.95 to -0.99; p = 0.008), stent diameter (adjusted HR: 0.37; 95% CI: 0.17to 0.81; p = 0.01) and bifurcations (adjusted HR: 2.1; 95% CI: 1.14 to 3.7; p = 0.02) emerged as independent predictors of thrombosis. In the subgroup of patients with bifurcations, the use of ZES was independently associated with a higher thrombosis rate (adjusted HR: 4; 95% CI: 1.1 to 13; p = 0.03). In a real practice setting, the incidence of thrombosis at 2 years with ZES and EES was low and quite similar. The incidence of very late thrombosis resulted lower than was reported in registries of first-generation DES. In the subset of bifurcations, the use of ZES significantly increased the risk of thrombosis. Copyright © 2010 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  2. 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…

  3. 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…

  4. 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.…

  5. [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.

  6. 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…

  7. 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…

  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. 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. 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…

  11. Monte Carlo simulation of the RBE of I-131 radiation using DNA damage as biomarker.

    PubMed

    Ezzati, Ahad Ollah; Mahmoud-Pashazadeh, Ali; Studenski, Matthew T

    2017-04-10

    In general, a weighting factor of one is applied for low linear energy transfer radiations. However, several studies indicate that relative biological effectiveness (RBE) of low energy photons and electrons is greater than one. The aim of this current study was calculating the RBE of I-131 radiation relative to Co-60 gamma photons in 100 μm spheroid cells using Monte Carlo (MC) simulations. These calculations were compared to experimentally measured results. MCNPX2.6 was used to simulate the I-131 and Co-60 irradiation setups and calculate the secondary electron spectra at energies higher than 1 keV with varying oxygen concentrations. The electron spectra at energies lower than 1 keV were obtained by extrapolation (down to 10 eV). The calculated electron spectra were input into the MCDS micro-dosimetric Monte Carlo code to calculate the DSB induction and related RBE. The calculated RBE of I-131 radiation relative to Co-60 photons, as the reference radiation recommended by the International Commission on Radiation Protection (ICRP), was 1.06, 1.03 and 1.02 for oxygen concentrations of 0, 5 and 100%, respectively. Results of MC simulations indicate the RBE of I-131 is greater than one. This finding, despite a 10% discrepancy with the findings of the previous in vitro study of one of the authors of this paper, reemphasizes that I-131 radiation induces more severe biological damage than current ICRP recommendations.

  12. Measured dose to ovaries and testes from Hodgkin's fields and determination of genetically significant dose

    SciTech Connect

    Niroomand-Rad, A.; Cumberlin, R. )

    1993-03-15

    The purpose of this study was to determine the genetically significant dose from therapeutic radiation exposure with Hodgkin's fields by estimating the doses to ovaries and testes. Phantom measurements were performed to verify estimated doses to ovaries and testes from Hodgkin's fields. Thermoluminescent LiF dosimeters (TLD-100) of 1 x 3 x 3 mm[sup 3] dimensions were embedded in phantoms and exposed to standard mantle and paraaortic fields using Co-60, 4 MV, 6 MV, and 10 MV photon beams. The results show that measured doses to ovaries and testes are about two to five times higher than the corresponding graphically estimated doses for Co-60 and 4 MVX photon beams as depicted in ICRP publication 44. In addition, the measured doses to ovaries and testes are about 30% to 65% lower for 10 MV photon beams than for their corresponding Co-60 photon beams. The genetically significant dose from Hodgkin's treatment (less than 0.01 mSv) adds about 4% to the genetically significant dose contribution to medical procedures and adds less than 1% to the genetically significant dose from all sources. Therefore, the consequence to society is considered to be very small. The consequences for the individual patient are, likewise, small. 28 refs., 3 figs., 5 tabs.

  13. Pilot scale experiments on radiation vulcanization of NR latex

    NASA Astrophysics Data System (ADS)

    Ridwan, M.

    The potential of irradiated latex as raw material of commercial use is under testing on pilot plant scale in Indonesia which has 225 kCi Co-60 irradiation facility and can irradiate 1000 tonnes of centrifuged latex per annum. The facility was jointly designed by BATAN of Indonesia and JAERI of Japan and was jointly financed by UNDP/IAEA, Government of Japan and Government of Indonesia under UNDP/IAEA Regional Cooperative Agreement Project on Industrial Application of Isotopes and Radiation Technology. The facility is a water pool type and can accomodate 400 kCi Co-60. The Co-60 rack has two shapes, plate and cylindrical shapes. The plate shape source is used for natural rubber latex irradiation and the cylindrical one is used for other irradiation services. The vulcanization system consists of three major components : emulsification unit ( height : 650 mm, diameter 500 mm ), mixing unit ( height : 1900mm, diameter 1200 mm ) and vulcanization reactor ( height : 1800 mm, diameter 1300 mm ). The first two components are located outside shielded room while the third one-in irradiation room. The radiation vulcanization process is a much simpler energy saving process comparedto the conventional thermal process which has two vulcanization steps before and after dipping. The physical and mechanical properties of irradiated NR Latex are comparable to those of sulfur vulcanized, and depend on many factors such as irradiation dose, sensitizer content, dry rubber content and storage time.

  14. Determination of C0-60 in Cobalt Slugs and Slabs and Radionuclides in Curium Sampler Slugs L-Reactor Disassembly Basin

    SciTech Connect

    Casella, V.R.

    2004-01-23

    Co-60 was historically produced in the SRS reactors. Cobalt slugs were irradiated in the early 1970s. Post-production, remaining cobalt slugs (including slab form) were consolidated for storage. There are approximately nine hundred cobalt slugs currently stored awaiting final disposition. These slugs had historically incomplete documentation for activity rates; therefore, assaying was required in order to determine their activity levels. Since the gamma dose rate from these slugs is extremely high, the most cost effective way to shield a source of this magnitude from personnel and the radiation detector was to use the basin water in which the slugs are stored as the shield. A sodium iodide gamma detector was placed above a specially designed air collimator assembly, so that slug was at least eight feet from the detector and was shielded by the basin water. Using a sodium iodide detector and multichannel analyzer system and an underwater collimator assembly, Co-60 concentrations we re determined for Disassembly Basin cobalt slugs and slabs and 18 curium sampler slugs. The total activity of all of the assayed slugs summed to 31,783 curies. 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.

  15. 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.

  16. Hepatobiliary kinetics after whole-body irradiation

    SciTech Connect

    Durakovic, A.

    1986-09-01

    The purpose of this investigation was to study hepatobiliary kinetics after whole-body gamma irradiation. Two groups of nine male beagle dogs were irradiated with a single whole body dose of 4- and 8-Gy cobalt-60 photons. Each animal was injected with 2 mCi Tc-99m DISIDA and scintigraphic studies were obtained with a gamma camera with a parallel hole multipurpose collimator. The parameters studied included: peak activity of the liver and gall bladder and gall bladder and intestinal visualization from the time of Tc-99m DISIDA administration. Total and indirect bilirubin, LDH, SGOT, and SGPT determined as baseline studies before irradiation and at different time intervals after irradiation were not changed in irradiated animals. Whole body Co-60 irradiation with 4 and 8 Gy produced no significant changes in the Tc-99m DISIDA visualization of the gall bladder or in the peak activity in the gall bladder or the liver 1 and 7 days after irradiation. Intestinal visualization occurred significantly earlier in 8 Gy Co-60 irradiated animals on both day 1 and day 7 post irradiation, compared to baseline values where it was never observed before 195.0 minutes. Gall bladder emptying is significantly accelerated after 8 Gy but not after 4-Gy Co-60 gamma irradiation. These observations suggest that gamma irradiation stimulates gall bladder contractility without modifying intrahepatic biliary kinetics.

  17. 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.

  18. 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 respostas escritas mais comuns da nossa pesquisa indicaram que os alunos precisam de mais orientação e melhor preparação para escrever ensaios bem sucedidos. Como os alunos consideraram difíceis os aspectos conceituais dos ensaios, no futuro iremos fornecer atividades relevantes antes dos ensaios para ajudar os alunos a escrevê-los com sucesso.

  19. 78 FR 71468 - Rules Relating to Additional Medicare Tax

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-29

    ... Federal sobre el Trabajo por Cuenta Propia (Incluyendo el Cr dito Tributario Adicional por Hijos para..., ``Planilla para la Declaraci n de la Contribuci n Federal sobre el Trabajo por Cuenta Propia (Incluyendo el...-SS or Form 1040- PR, ``Planilla para la Declaraci n de la Contribuci n Federal sobre el Trabajo por...

  20. Teaching Kids About Using Medicine Safely

    MedlinePlus

    ... videos for consumers on YouTube Enseñando a los Niños Sobre el Uso de Medicamentos Seguramente Vea este ... de la FDA sobre la enseñanza de los niños mayores sobre el uso de medicinas seguramente. back ...

  1. [Analysis of food service and opinion of its users in a Catalan prison].

    PubMed

    Sáiz Izquierdo, María Elena; Fornons Fontdevila, David; Medina Luque, F Xavier; Aguilar Martínez, Alicia

    2014-07-01

    INTRODUCCIÓN: Los estudios sobre restauración colectiva se encuentran viviendo un cierto auge en España. Sin embargo, se dispone de muy poca información sobre cómo se organiza este servicio en las instituciones penitenciarias, y mucho menos aún sobre cómo es percibido por sus usuarios.

  2. 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.

  3. Differential gene expression in primary fibroblasts induced by proton and cobalt-60 beam irradiation.

    PubMed

    Nielsen, Steffen; Bassler, Niels; Grzanka, Leszek; Swakon, Jan; Olko, Pawel; Andreassen, Christian Nicolaj; Overgaard, Jens; Alsner, Jan; Sørensen, Brita Singers

    2017-09-08

    Proton beam therapy delivers a more conformal dose distribution than conventional radiotherapy, thus improving normal tissue sparring. Increasing linear energy transfer (LET) along the proton track increases the relative biological effectiveness (RBE) near the distal edge of the Spread-out Bragg peak (SOBP). The severity of normal tissue side effects following photon beam radiotherapy vary considerably between patients. The dual study aim was to identify gene expression patterns specific to radiation type and proton beam position, and to assess whether individual radiation sensitivity influences gene expression levels in fibroblast cultures irradiated in vitro. The study includes 30 primary fibroblast cell cultures from patients previously classified as either radiosensitive or radioresistant. Cells were irradiated at three different positions in the proton beam profile: entrance, mid-SOBP and at the SOBP distal edge. Dose was delivered in three fractions × 3.5 Gy(RBE) (RBE 1.1). Cobalt-60 (Co-60) irradiation was used as reference. Real-time qPCR was performed to determine gene expression levels for 17 genes associated with inflammation response, fibrosis and angiogenesis. Differences in median gene expression levels were observed for multiple genes such as IL6, IL8 and CXCL12. Median IL6 expression was 30%, 24% and 47% lower in entrance, mid-SOBP and SOBP distal edge groups than in Co-60 irradiated cells. No genes were found to be oppositely regulated by different radiation qualities. Radiosensitive patient samples had the strongest regulation of gene expression; irrespective of radiation type. Our findings indicate that the increased LET at the SOBP distal edge position did not generally lead to increased transcriptive response in primary fibroblast cultures. Inflammatory factors were generally less extensively upregulated by proton irradiation compared with Co-60 photon irradiation. These effects may possibly influence the development of normal tissue

  4. SU-E-T-36: A GPU-Accelerated Monte-Carlo Dose Calculation Platform and Its Application Toward Validating a ViewRay Beam Model

    SciTech Connect

    Wang, Y; Mazur, T; Green, O; Hu, Y; Wooten, H; Yang, D; Zhao, T; Mutic, S; Li, H

    2015-06-15

    Purpose: To build a fast, accurate and easily-deployable research platform for Monte-Carlo dose calculations. We port the dose calculation engine PENELOPE to C++, and accelerate calculations using GPU acceleration. Simulations of a Co-60 beam model provided by ViewRay demonstrate the capabilities of the platform. Methods: We built software that incorporates a beam model interface, CT-phantom model, GPU-accelerated PENELOPE engine, and GUI front-end. We rewrote the PENELOPE kernel in C++ (from Fortran) and accelerated the code on a GPU. We seamlessly integrated a Co-60 beam model (obtained from ViewRay) into our platform. Simulations of various field sizes and SSDs using a homogeneous water phantom generated PDDs, dose profiles, and output factors that were compared to experiment data. Results: With GPU acceleration using a dated graphics card (Nvidia Tesla C2050), a highly accurate simulation – including 100*100*100 grid, 3×3×3 mm3 voxels, <1% uncertainty, and 4.2×4.2 cm2 field size – runs 24 times faster (20 minutes versus 8 hours) than when parallelizing on 8 threads across a new CPU (Intel i7-4770). Simulated PDDs, profiles and output ratios for the commercial system agree well with experiment data measured using radiographic film or ionization chamber. Based on our analysis, this beam model is precise enough for general applications. Conclusions: Using a beam model for a Co-60 system provided by ViewRay, we evaluate a dose calculation platform that we developed. Comparison to measurements demonstrates the promise of our software for use as a research platform for dose calculations, with applications including quality assurance and treatment plan verification.

  5. Estimation of radioactive contamination of soils from the "Balapan" and the "Experimental field" technical areas of the Semipalatinsk nuclear test site.

    PubMed

    Evseeva, T; Belykh, E; Geras'kin, S; Majstrenko, T

    2012-07-01

    In spite of the long history of the research, radioactive contamination of the Semipalatinsk nuclear test site (SNTS) in the Republic of Kazakhstan has not been adequately characterized. Our cartographic investigation has demonstrated highly variable radioactive contamination of the SNTS. The Cs-137, Sr-90, Eu-152, Eu-154, Co-60, and Am-241 activity concentrations in soil samples from the "Balapan" site were 42.6-17646, 96-18250, 1.05-11222, 0.6-4865, 0.23-4893, and 1.2-1037 Bq kg(-1), correspondingly. Cs-137 and Sr-90 activity concentrations in soil samples from the "Experimental field" site were varied from 87 up to 400 and from 94 up to 1000 Bq kg(-1), respectively. Activity concentrations of Co-60, Eu-152, and Eu-154 were lower than the minimum detectable activity of the method used. Concentrations of naturally occurring radionuclides (K-40, Ra-226, U-238, and Th-232) in the majority of soil samples from the "Balapan" and the "Experimental field" sites did not exceed typical for surrounding of the SNTS areas levels. Estimation of risks associated with radioactive contamination based on the IAEA clearance levels for a number of key radionuclides in solid materials shows that soils sampled from the "Balapan" and the "Experimental field" sites might be considered as radioactive wastes. Decrease in specific activity of soil from the sites studied up to safety levels due to Co-60, Cs-137, Sr-90, Eu-152, Eu-154 radioactive decay and Am-241 accumulation-decay will occur not earlier than 100 years. In contrast, soils from the "Experimental field" and the "Balapan" sites (except 0.5-2.5 km distance from the "Chagan" explosion point) cannot be regarded as the radioactive wastes according safety norms valid in Russia and Kazakhstan.

  6. Cellular parameters for track structure modelling of radiation hazard in space

    NASA Astrophysics Data System (ADS)

    Hollmark, M.; Lind, B.; Gudowska, I.; Waligorski, M.

    Based on irradiation with 45 MeV/u N and B ions and with Co-60 gamma rays, track structure cellular parameters have been fitted for V 79-379A Chinese hamster lung fibroblasts and for human melanoma cells (AA wtp53). These sets of parameters will be used to develop a calculation of radiation hazard in deep space, based on the system for evaluating, summing and reporting occupational exposures proposed in 1967 by subcommittee of the NCRP, but never issued as an NCRP report. The key concepts of this system were: i) expression of the risk from all radiation exposures relative to that from a whole-body exposure to Co-60 radiation; ii) relating the risk from any exposure to that of the standard (Co-60) radiation through an "effectiveness factor" (ef), a product of sub-factors representing radiation quality, body region irradiated, and depth of penetration of radiation; the product of absorbed dose by ef being termed the "exposure record unit" (eru); iii) development of ef values and a cumulative eru record for external and internal emitters. Application of this concept should provide a better description of the Gy -equivalent presently in use by NASA for evaluating risk in deep space than the equivalent dose, following ICRP-60 recommendations. Dose and charged particle fluence levels encountered in space, particularly after Solar Particle Events, require that deterministic rather than stochastic effects be considered. Also, synergistic effects due to simultaneous multiple charged particle transfers, may have to be considered. Thus, models applicable in radiotherapy, where the Gy -equivalent is also applied, in conjunction with transport calculations performed using, e.g. the ADAM and EVA phantoms, along the concepts of the 1967 NCRP system, may be more appropriate for evaluating the radiation hazard from external fields with a large flux and a major high-LET component.

  7. 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

  8. 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.

  9. 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.

  10. Comparison of planned and measured rectal dose in-vivo during high dose rate Cobalt-60 brachytherapy of cervical cancer.

    PubMed

    Zaman, Z K; Ung, N M; Malik, R A; Ho, G F; Phua, V C E; Jamalludin, Z; Baharuldin, M T H; Ng, K H

    2014-12-01

    Cobalt-60 (Co-60) is a relatively new source for the application of high-dose rate (HDR) brachytherapy. Radiation dose to the rectum is often a limiting factor in achieving the full prescribed dose to the target during brachytherapy of cervical cancer. The aim of this study was to measure radiation doses to the rectum in-vivo during HDR Co-60 brachytherapy. A total of eleven HDR brachytherapy treatments of cervical cancer were recruited in this study. A series of diodes incorporated in a rectal probe was inserted into the patient's rectum during each brachytherapy procedure. Real-time measured rectal doses were compared to calculated doses by the treatment planning system (TPS). The differences between calculated and measured dose ranged from 8.5% to 41.2%. This corresponds to absolute dose differences ranging from 0.3 Gy to 1.5 Gy. A linear relationship was observed between calculated and measured doses with linear regression R(2) value of 0.88, indicating close association between the measured and calculated doses. In general, absorbed doses for the rectum as calculated by TPS were observed to be higher than the doses measured using the diode probe. In-vivo dosimetry is an important quality assurance method for HDR brachytherapy of cervical cancer. It provides information that can contribute to the reduction of errors and discrepancies in dose delivery. Our study has shown that in-vivo dosimetry is feasible and can be performed to estimate the dose to the rectum during HDR brachytherapy using Co-60.

  11. 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.

  12. An analysis of the regulatory program of quality audits in radiotherapy in Brazil from 1995 to 2007.

    PubMed

    de Paiva, Eduardo; da Rosa, Luiz A R; Brito, Ricardo R A; de Sá, Lidia V; Dovales, Ana C M; Batista, Delano V S; Giannoni, Ricardo A; Velasco, Alexandre F

    2011-01-30

    The Brazilian Institute of Radiation Protection and Dosimetry (IRD/CNEN) carried out quality assurance regulatory audits in Brazilian radiotherapy facilities from 1995 to 2007. In this work, the set of data collected from 195 radiotherapy facilities that use high-energy photon beams are analyzed. They include results from audits in linear electron accelerators and/or Co-60 units. The inspectors of IRD/CNEN performed the dosimetry of high-energy radiotherapy photon beams according to the IAEA dosimetry protocols TRS 277 and TRS 398, and the values of measurements were compared to stated values. Other aspects of radiological protection were checked during on-site audits such as calibration certification of clinical dosimeters and portable monitors, existence and use of check source, use of barometer and thermometer, individual dose registry and training of staff. It was verified that no check source was available in 38% of the visited facilities; the training of personnel was not adequate in 9% of the facilities and the registry of accumulated individual doses was not being done in 6% of the facilities. Measurements of absorbed dose have indicated deviations in the range ± 3% for 67.6% of the cobalt-60 units and 79.6% of medical linear accelerators; 18.5% of Co-60 irradiators and 9.6% of linear accelerators presented deviations in the range 3% < δ ≤ 5%. Finally, 13.9% of Co-60 facilities and 10.8% of linear accelerator facilities presented dosimetry deviations above 5%. The effort in dosimetric quality control performed by IRD/CNEN audits has yielded positive changes that make radiation treatment facilities more reliable.

  13. On the production of cosmogenic nuclides by low-energy neutrons

    NASA Astrophysics Data System (ADS)

    Fanenbruck, O.; Lange, H.-J.; Michel, R.

    1994-07-01

    Monte Carlo codes describing the propagation and interaction of medium-energy particles in matter, in combination with experimental and theoretical cross sections of the underlying nuclear reactions, were successfully applied in model calculations of cosmogenic nuclide production rates. We extended these calculations to reactions of low-energy neutrons in order to allow a consistent interpretation of the entire regime of nuclear reactions involved in galactic cosmic ray (GCR) interactions. Low-energy neutron spectra were calculated for stony meteoroids and lunar surface materials by Monte Carlo techniques using the MORSE code, Emmett (1975), within the HERMES code system. Depth- and size-dependent production rates for the production of Cl-36, Ca-41, Co-60, Ni-59, Kr-80, and Kr-82 by neutron capture were derived by folding these spectra with group cross sections calculated from microscopic neutron-capture data of the evaluated neutron data file ENDF/B VI by the code NJOY. The calculations were validated by modeling the Co-60 production in an artificial stony meteoroid irradiated isotropically by 1.6 GeV protons. The new theoretical production rates were compared with earlier calculations of low-energy neutron capture by Eberhardt et al. and by Spergel et al. (n,gamma)-produced cosmogenic nuclides are sensitive indicators of meteoroid sizes. The extension of the model calculations to longlived and stable (n,gamma) products frees this method from the uncertainties caused by the short-term GCR variations that significantly affect Co-60 production rates. The new production rates are applied to the interpretation of the existing experimental data of (n,gamma) products in lunar drill cores and in meteorites.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Storage of pork by irradiation

    NASA Astrophysics Data System (ADS)

    Shupei, Liu; Renli, Yang; Chixum, Chen; Yongzhi, Wang; Zhen, Sun

    In this paper the study of storage of pork, irradiated with Co-60 gamma rays, is recommended. The changes of the appearance and the main qualitative, indexes of pork, irradiated with 1.5 M rad radiation and after two month's storage, were analysed. The evaluation of storage. Transportation and nutritional acceptability of the two kinds of irradiated pork products was made. Systematic toxicological tests of rats and dogs, fed with irradiated pork, were given. The comparison of the economic facilitation of refrigerated pork and irradiated pork was made

  19. Guidelines for Selecting Control and Treatment Options for Contaminated Dredged Material.

    DTIC Science & Technology

    1986-09-01

    This level increases organics removal to 95 percent. viii NO ’% V 1 d. Level IV is treatment to remove nutrients such as ammonia and phosphorus. e...metals. Clinoptilolite (Cu ;’n Cd - Pb) and mordenite (;: Zn; and Co &#60 Cu M n) both show selective exchange of heavv metals. As wtti all ion exchangers...Equalization Sulfides >100 mg/i Precipitation or stripping with recovery Phenols >70-300 mg/i Extraction, adsorption, internal dilution Ammonia >1.6 g/k

  20. 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.

  1. Feasibility study on utilization of vitrified wastes as radiation sources

    NASA Astrophysics Data System (ADS)

    Makuuchi, K.; Yoshii, F.; Hyakutake, K.

    1995-02-01

    A feasibility study on utilization of vitrified high level waste as radiation source has been carried out. Natural rubber latex was radiation vulcanized with VW to demonstrate the feasibility. The dose rate was 0.1 kGy/hr. As a sensitizer, n-butyl acrylate was added. Negligible small activation of NR latex by neutron from the waste was observed. The residual sensitizer in the irradiated latex and physical properties of film molded from the irradiated latex were the same level with the conventional RVNRL with gamma-rays from Co-60. These results suggested that vitrified high level waste can be used as an industrial radiation source.

  2. 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.

  3. Effect of co-doping of sodium on the thermoluminescence dosimetry properties of copper-doped zinc lithium borate glass system.

    PubMed

    Saidu, A; Wagiran, H; Saeed, M A; Alajerami, Y S M; Kadir, A B A

    2016-12-01

    The effect of sodium as a co-dopant on the thermoluminescence (TL) properties of copper-doped zinc lithium borate (ZLB: Cu) subjected to Co-60 gamma radiation is reported in this study. TL intensity is enhanced with the introduction of sodium in ZLB: Cu. The obtained glow curve is simple with a single peak. The annealing procedure and the best heating rate for the proposed thermoluminescent dosimeter (TLD) are established, and the phosphor is reusable. The TL response within the dose range of 0.5-1000Gy is investigated. The results show that the thermal fading behaviour is improved significantly.

  4. 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.

  5. The changes in optical absorbance of ZrO{sub 2} thin film with the rise of the absorbed dose

    SciTech Connect

    Abayli, D. Baydogan, N.

    2016-03-25

    In this study, zirconium oxide (ZrO{sub 2}) 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 ZrO{sub 2} thin film samples with the rise of the absorbed dose. The changes in the optical absorbance of ZrO{sub 2} 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.

  6. 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.

  7. [Effect of ozone and ionizing radiation on an in vitro model--a pilot study of 4 gynecologic tumors].

    PubMed

    Karlic, H; Kucera, H; Metka, M; Schönbauer, M; Söregi, G

    1987-01-01

    In order to investigate the sensibility of cultured tumor cells to ozone and irradiation primary tissue cultures from one undifferentiated non-classified ovarian carcinoma, two solid adenocarcinomas of the ovary and one endometrial carcinoma were established. Cultivation was performed according to standard techniques involving the stem cell assay in soft agar as well as the monolayer technique in liquid nutrient media. The type of culture system did not influence the sensitivity of the culture cells to ozone and/or irradiation. Ozone treatment was performed with three different Ozone concentrations (0.03 ppm, 0.1 ppm, 0.3 ppm). Irradiation was done with 100 rd Ra226, Ir192 or Co60. A control experiment showed that the proliferative tendency of benign cells (skin fibroblasts) was not inhibited by the three ozone concentrations used in this study. Ra226 and even the combination of ozone and Radium did not influence the proliferative activity of these benign cells. Ir192 and Co60 were cytotoxic to benign as well as to carcinoma cells. Cultivated cells from endometrial carcinoma resisted to ozone treatment as well as to Ra226 (but they were destroyed by Ir119 and Co60). After pretreatment with ozone (0.1 ppm), Ra226 treatment of endometrial carcinoma cells induced a cytostatic effect implying that no cell divisions were observed after irradiation and the cells lysed within two weeks after irradiation. For the three ovarian carcinoma cell lines analysed in this study ozone treatment had a cytostatic effect even at the lowest concentration (0.03 ppm), with the two higher ozone concentrations a cytotoxic effect could be induced in ovarian carcinoma cells. Exclusive treatment with Ra226 induced a cytostatic effect, but it was cytotoxic after combination with ozone treatment of the lowest concentration (Ir192 and Co60 were cytotoxic in all cases). Our investigation confirmed the radiosensitizing effect of ozone treatment. Furthermore it was shown that exclusive ozone

  8. 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.

  9. Artificial Intelligence/Robotics Applications to Navy Aircraft Maintenance.

    DTIC Science & Technology

    1984-06-01

    AD-A143 219 ARTIFICIAL INTELLIGENCE/ROBOTICS APPLICATIONS TO NAVV T7T AIRCRAFT HAINTENANCE(U) SRI INTERNATIONAL HENLO PARK CA D R BROWN ET AL...34^! * -.’.-. v.’: ;- • ’_*-••.-. - - m i i • i >«••»......» i 0> CO &#60 Final Report ARTIFICIAL INTELLIGENCE/ROBOTICS APPLICATIONS TO NAVY...8217• . . i * • ’ * ’ ** ’.- *_» "-_ _* _- _• -J> . „• „ (ss3 QB e 25 f//w/ Report ARTIFICIAL INTELLIGENCE/ROBOTICS APPLICATIONS TO NAVY

  10. Radiation-induced grafting of acrylamide onto guar gum in aqueous medium: Synthesis and characterization of grafted polymer guar-g-acrylamide

    NASA Astrophysics Data System (ADS)

    Biswal, Jayashree; Kumar, Virendra; Bhardwaj, Y. K.; Goel, N. K.; Dubey, K. A.; Chaudhari, C. V.; Sabharwal, S.

    2007-10-01

    Mutual radiation grafting technique has been applied to carry out grafting of acrylamide (AAm) onto guar gum (GG) using high-energy Co 60γ radiation to enhance its flocculating properties for industrial effluents. The grafted product was characterized using analytical probes like elemental analysis, thermal analysis, Fourier transformed infrared (FTIR), X-ray diffraction (XRD) and scanning electron microscope (SEM). The grafting extent was observed to decrease with the dose rate and increase with the concentration of AAm. Thermo gravimetric analysis (TGA) of grafted and ungrafted samples indicated better stability of grafted product. γ and microwave radiation effect on grafted and virgin GG has also been reported.

  11. 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.

  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. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. 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.

  19. Comparison of concentrations of natural and artifical radionuclides in Plankton from French Polynesian and Australian coastal waters

    SciTech Connect

    Poletiko, C.; Twining, J.R.; Jeffree, R.A.

    1994-12-31

    Zooplankton samples from French Polynesian and Australian coastal waters were analysed for natural and artificial radionuclides. Quality control was assured by correlating replicate analyses between three laboratories and by intercomparison exercise. Pu-2.39/240 was detected sporadically among samples from both regions, with the highest levels being more consistently found in Tuamotu-Gambier samples. The artificial radionuclides Cs-137, Cs-134, Sr-90 and Co-60 were not detected. Of the natural nuclides, Ac-228 was detected in shallow continental waters off Northern Australia and an inverse relationship (P< 0.02) was established between plankton density and their Po-210 concentration.

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

    PubMed

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

    2016-06-07

    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.

  1. 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.

  2. Radiotherapy for eosinophilic granuloma of bone. [X-ray; /sup 60/Co

    SciTech Connect

    Pereslegin, I.A.; Ustinova, V.F.; Podlyaschuk, E.L.

    1981-03-01

    This paper presents a study of 93 patients with eosinophilic granuloma of bone of different locations, who received radiotherapy in our Institute from 1953 to 1978. One hundred eighty four lesions were irradiated. In 118 patients, radiotherapy was used alone; it was used as part of combined treatment in 68 patients. The results and methods of radiotherapy are discussed. The following radiotherapeutic methods were used depending on the lesion site: gammatherapy (Co-60), orthvoltage x ray therapy and short distance x ray therapy (100 kv, SSD-10 cm). The follow-up periods ranged from 1 to 25 years.

  3. 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.

  4. 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.

  5. The influence of 175 MeV nickel ion irradiation on the electrical characteristics of power transistors (HF13)

    NASA Astrophysics Data System (ADS)

    Pushpa, N.; Praveen, K. C.; Gnana Prakash, A. P.; Naik, P. S.; Gupta, S. K.; Revannasiddaiah, D.

    2012-10-01

    The dc electrical characteristics of NPN RF power transistors were studied systematically before and after 175 MeV Ni13+ ion and Co-60 gamma irradiation in the dose range from 100 krad to 100 Mrad. The transistor parameters such as excess base current (ΔIB= IBpost-IBpre), dc current gain (hFE), and collector-saturation current (ICSat) were studied. The base current (IB) was found to increase significantly after irradiation and this in turn decreases the hFE of the transistors. Further, the output characteristics of the irradiated devices exhibit the decrease in the collector current at the saturation region (ICSat) with increase of radiation dose.

  6. Stobadine pretreatment enhances glutathione peroxidase activity in the heart of irradiated mice.

    PubMed

    Kováciková, Z; Chorvatovicová, D; Ginter, E

    1997-05-01

    The effect of pretreatment with stobadine (a novel drug with cardioprotective properties) on the activity of glutathione peroxidase was studied in the heart of mice after Co60 irradiation. Exposure to 6.5 Gy caused significant decrease in the activity of the enzyme (p < 0.01). Treatment with stobadine (70.07 mg/kg) 1 or 2 h before irradiation resulted in activity enhancement in comparison with the nonpretreated irradiated group (p < 0.01). We conclude that the radical scavenging mechanism may be involved in the protection exerted by stobadine. The results are in agreement with those obtained by the micronucleus test.

  7. 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.

  8. ESR of gamma irradiated single crystals of cholesteryl acetate and cholesteryl chloroformate

    NASA Astrophysics Data System (ADS)

    Yigit, B. T.; Ozmen, A.; Ercan, I.; Eken, M.; Birey, M.

    2003-11-01

    Cholesteryl acetate and cholesteryl chloroformate compounds have been irradiated with Co-60-gamma rays at room temperatures. The irradiated samples have been examined for paramagnetic resonance, and the observed spectra in several cases have been identified with specific radicals. The results in each case have been considered in relation to the present knowledge of the radiation chemistry of the compound. The single crystals have been investigated between 120 and 300 K. The spectra are found to be temperature independent and radiation damage centers are attributed to CHCH2 radical for cholesteryl acetate and CH3 and CHCH2CH2CH2 radicals for cholesteryl chloroformate.

  9. EPR of gamma irradiated single crystals of cholesteryl benzoate

    NASA Astrophysics Data System (ADS)

    Caliskan, B.; Aras, E.; Asik, B.; Buyum, M.; Birey, M.

    2004-01-01

    The cholesteryl benzoate compound has been irradiated with Co-60-gamma rays at room temperature. The irradiated samples have been examined for paramagnetic resonance, and in several cases the observed spectra could be identified with specific radicals. In each case the results have been considered in relation to the present knowledge of the radiation chemistry of the compound. The single crystals have been investigated between 123 and 300 K. The spectrum parameters are found to be temperature independent. Radiation damage centers are attributed to CHCH2 and CHCH2CH2 radicals. The g values and the hyperfine coupling constants of the unpaired electron with the protons were determined.

  10. Technical Note: A Monte Carlo study of magnetic-field-induced radiation dose effects in mice

    SciTech Connect

    Rubinstein, Ashley E.; Liao, Zhongxing; Melancon, Adam D.; Followill, David S.; Tailor, Ramesh C.; Guindani, Michele; Hazle, John D.; Court, Laurence E.

    2015-09-15

    Purpose: Magnetic fields are known to alter radiation dose deposition. Before patients receive treatment using an MRI-linear accelerator (MRI-Linac), preclinical studies are needed to understand the biological consequences of magnetic-field-induced dose effects. In the present study, the authors sought to identify a beam energy and magnetic field strength combination suitable for preclinical murine experiments. Methods: Magnetic field dose effects were simulated in a mouse lung phantom using various beam energies (225 kVp, 350 kVp, 662 keV [Cs-137], 2 MV, and 1.25 MeV [Co-60]) and magnetic field strengths (0.75, 1.5, and 3 T). The resulting dose distributions were compared with those in a simulated human lung phantom irradiated with a 6 or 8 MV beam and orthogonal 1.5 T magnetic field. Results: In the human lung phantom, the authors observed a dose increase of 45% and 54% at the soft-tissue-to-lung interface and a dose decrease of 41% and 48% at the lung-to-soft-tissue interface for the 6 and 8 MV beams, respectively. In the mouse simulations, the magnetic fields had no measurable effect on the 225 or 350 kVp dose distribution. The dose increases with the Cs-137 beam for the 0.75, 1.5, and 3 T magnetic fields were 9%, 29%, and 42%, respectively. The dose decreases were 9%, 21%, and 37%. For the 2 MV beam, the dose increases were 16%, 33%, and 31% and the dose decreases were 9%, 19%, and 30%. For the Co-60 beam, the dose increases were 19%, 54%, and 44%, and the dose decreases were 19%, 42%, and 40%. Conclusions: The magnetic field dose effects in the mouse phantom using a Cs-137, 3 T combination or a Co-60, 1.5 or 3 T combination most closely resemble those in simulated human treatments with a 6 MV, 1.5 T MRI-Linac. The effects with a Co-60, 1.5 T combination most closely resemble those in simulated human treatments with an 8 MV, 1.5 T MRI-Linac.

  11. THE ROLE OF IONS IN THE RADIOLYSIS OF ORGANIC LIQUIDS.

    DTIC Science & Technology

    substituted for SnCl4, a different product pattern was found. Squalene was irradiated with Co-60 gamma rays at room temperature and with 1-Mev...crosslinked fraction. Increased yields (on the basis of energy absorbed in the solute) were observed for the cis-trans isomerization of squalene and cis...and trans-polyisoprene when these were irradiated in benzene solution. The chlorination of toluene and the cyclization of cross-linked squalene are believed to have ionic intermediates. (Author)

  12. Department of the Navy FY 1996/FY 1997 Biennial Budget Estimates. Justification of Estimates, Budget Activity 7, February 1995. Research, Development Test and Evaluation, Navy Descriptive Summaries

    DTIC Science & Technology

    1995-02-01

    o i_» tu 2 ^ !i f tt- t- 2 * U. w tipo _ -^ I ^ ^ E ►< a < ( Z/\\ SS’S 5? o«»ooo«» Sc W r^i c/D t 0s: s;j •. o...r* e pie ?"* ^g X 1 & IS X a a a i a s i » •n Q CO u z 3 ADA29303: Q tu 55 CO &#60 J U 2 3 c hi hi Q

  13. 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.

  14. 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.

  15. Technical Note: A Monte Carlo study of magnetic-field-induced radiation dose effects in mice.

    PubMed

    Rubinstein, Ashley E; Liao, Zhongxing; Melancon, Adam D; Guindani, Michele; Followill, David S; Tailor, Ramesh C; Hazle, John D; Court, Laurence E

    2015-09-01

    Magnetic fields are known to alter radiation dose deposition. Before patients receive treatment using an MRI-linear accelerator (MRI-Linac), preclinical studies are needed to understand the biological consequences of magnetic-field-induced dose effects. In the present study, the authors sought to identify a beam energy and magnetic field strength combination suitable for preclinical murine experiments. Magnetic field dose effects were simulated in a mouse lung phantom using various beam energies (225 kVp, 350 kVp, 662 keV [Cs-137], 2 MV, and 1.25 MeV [Co-60]) and magnetic field strengths (0.75, 1.5, and 3 T). The resulting dose distributions were compared with those in a simulated human lung phantom irradiated with a 6 or 8 MV beam and orthogonal 1.5 T magnetic field. In the human lung phantom, the authors observed a dose increase of 45% and 54% at the soft-tissue-to-lung interface and a dose decrease of 41% and 48% at the lung-to-soft-tissue interface for the 6 and 8 MV beams, respectively. In the mouse simulations, the magnetic fields had no measurable effect on the 225 or 350 kVp dose distribution. The dose increases with the Cs-137 beam for the 0.75, 1.5, and 3 T magnetic fields were 9%, 29%, and 42%, respectively. The dose decreases were 9%, 21%, and 37%. For the 2 MV beam, the dose increases were 16%, 33%, and 31% and the dose decreases were 9%, 19%, and 30%. For the Co-60 beam, the dose increases were 19%, 54%, and 44%, and the dose decreases were 19%, 42%, and 40%. The magnetic field dose effects in the mouse phantom using a Cs-137, 3 T combination or a Co-60, 1.5 or 3 T combination most closely resemble those in simulated human treatments with a 6 MV, 1.5 T MRI-Linac. The effects with a Co-60, 1.5 T combination most closely resemble those in simulated human treatments with an 8 MV, 1.5 T MRI-Linac.

  16. Technical Note: A Monte Carlo study of magnetic-field-induced radiation dose effects in mice

    PubMed Central

    Liao, Zhongxing; Melancon, Adam D.; Guindani, Michele; Followill, David S.; Tailor, Ramesh C.; Hazle, John D.; Court, Laurence E.

    2015-01-01

    Purpose: Magnetic fields are known to alter radiation dose deposition. Before patients receive treatment using an MRI-linear accelerator (MRI-Linac), preclinical studies are needed to understand the biological consequences of magnetic-field-induced dose effects. In the present study, the authors sought to identify a beam energy and magnetic field strength combination suitable for preclinical murine experiments. Methods: Magnetic field dose effects were simulated in a mouse lung phantom using various beam energies (225 kVp, 350 kVp, 662 keV [Cs-137], 2 MV, and 1.25 MeV [Co-60]) and magnetic field strengths (0.75, 1.5, and 3 T). The resulting dose distributions were compared with those in a simulated human lung phantom irradiated with a 6 or 8 MV beam and orthogonal 1.5 T magnetic field. Results: In the human lung phantom, the authors observed a dose increase of 45% and 54% at the soft-tissue-to-lung interface and a dose decrease of 41% and 48% at the lung-to-soft-tissue interface for the 6 and 8 MV beams, respectively. In the mouse simulations, the magnetic fields had no measurable effect on the 225 or 350 kVp dose distribution. The dose increases with the Cs-137 beam for the 0.75, 1.5, and 3 T magnetic fields were 9%, 29%, and 42%, respectively. The dose decreases were 9%, 21%, and 37%. For the 2 MV beam, the dose increases were 16%, 33%, and 31% and the dose decreases were 9%, 19%, and 30%. For the Co-60 beam, the dose increases were 19%, 54%, and 44%, and the dose decreases were 19%, 42%, and 40%. Conclusions: The magnetic field dose effects in the mouse phantom using a Cs-137, 3 T combination or a Co-60, 1.5 or 3 T combination most closely resemble those in simulated human treatments with a 6 MV, 1.5 T MRI-Linac. The effects with a Co-60, 1.5 T combination most closely resemble those in simulated human treatments with an 8 MV, 1.5 T MRI-Linac. PMID:26328998

  17. Hazardous and Corrosive Gas Production in the Radiolysis of Water/Organic Mixtures in Model TRU Waste

    SciTech Connect

    LaVerne, Jay A.

    2005-06-01

    Experiments in combination with diffusion-kinetic modeling incorporating track structure simulations are used to examine the radiation chemistry of aqueous systems containing chlorinated hydrocarbons. Irradiations with both Co-60 gamma rays and alpha particles are employed in order to simulate typical mixed radiation environments encountered in waste management. The goal is to determine fundamental mechanisms, kinetics, and yields for the formation of potentially explosive gases and corrosive agents, such as H2 and HCl, respectively, in the radiolysis of water-organic mixtures. The radiation chemical systems studied are found throughout the DOE portfolio and are important in radioactive waste remediation and management.

  18. An overview of zinc addition for BWR dose rate control

    SciTech Connect

    Marble, W.J.

    1995-03-01

    This paper presents an overview of the BWRs employing feedwater zinc addition to reduce primary system dose rates. It identifies which BWRs are using zinc addition and reviews the mechanical injection and passive addition hardware currently being employed. The impact that zinc has on plant chemistry, including the factor of two to four reduction in reactor water Co-60 concentrations, is discussed. Dose rate results, showing the benefits of implementing zinc on either fresh piping surfaces or on pipes with existing films are reviewed. The advantages of using zinc that is isotopically enhanced by the depletion of the Zn-64 precursor to Zn-65 are identified.

  19. Wood plastic composite at different urea concentrations

    NASA Astrophysics Data System (ADS)

    Husain, M. M.; Khan, Mubarak A.; Ali, K. M. Idriss; Hasan, A. J. M. Moynul

    1995-04-01

    Wood plastic composite (WPC) has been prepared with a low grade wood simul ( Salmalia malabarica) of Bangladesh under Co-60 gamma irradiation using MMA as the bulk monomer combined with methanol as the swelling solvent at different urea concentrations. Effect of a second solute such as NVP, TPGDA and TMPTA in the impregnating solution is evaluated. NVP appears to be the best co-additive/second solute among all the additives used to yield the composite with the highest polymer loading (PL) and tensile strength (TS) at 0.5% urea concentration.

  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. 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.

  2. Quality index of oils extracted from gamma-irradiated peanuts (Arachis hypogaea L.) of the golden and bari varieties.

    PubMed

    Bhatti, Ijaz Ahmad; Ashraf, Syra; Shahid, Muhammad; Asi, Muhammad Rafique; Mehboob, Shahid

    2010-12-01

    Two varieties of peanuts were irradiated to 4, 6 and 8 kGy with Co(60). Their proximate compositions remained unaffected, but microbes were eliminated completely after irradiation to 8 kGy. HPLC was used to study tocopherols of irradiated and unirradiated oil samples. There were dose-dependent differences in physico-chemical values between the control and irradiated samples. Significant changes in tocopherol concentrations and peroxide values in the oils were observed after irradiation to 8 kGy. Fatty acid compositions did not change significantly. The study has shown that irradiation is an effective tool in preservation of peanut oil. Copyright 2010 Elsevier Ltd. All rights reserved.

  3. SU-F-BRA-10: Fricke Dosimetry: Determination of the G-Value for Ir-192 Energy Based On the NRC Methodology

    SciTech Connect

    Salata, C; David, M; Rosado, P; Almeida, C de

    2015-06-15

    Purpose: Use the methodology developed by the National Research Council Canada (NRC), for Fricke Dosimetry, to determine the G-value used at Ir-192 energies. Methods: In this study the Radiology Science Laboratory of Rio de Janeiro State University (LCR),based the G-value determination on the NRC method, using polyethylene bags. Briefly, this method consists of interpolating the G-values calculated for Co-60 and 250 kV x-rays for the average energy of Ir-192 (380 keV). As the Co-60 G-value is well described at literature, and associated with low uncertainties, it wasn’t measured in this present study. The G-values for 150 kV (Effective energy of 68 keV), 250 kV (Effective energy of 132 keV)and 300 kV(Effective energy of 159 keV)were calculated using the air kerma given by a calibrated ion chamber, and making it equivalent to the absorbed to the Fricke solution, using a Monte Carlo calculated factor for this conversion. Instead of interpolations, as described by the NRC, we displayed the G-values points in a graph, and used the line equation to determine the G- value for Ir-192 (380 keV). Results: The measured G-values were 1.436 ± 0.002 µmol/J for 150 kV, 1.472 ± 0.002 µmol/J for 250 kV, 1.497 ± 0.003 µmol/J for 300 kV. The used G-value for Co-60 (1.25 MeV) was 1,613 µmol/J. The R-square of the fitted regression line among those G-value points was 0.991. Using the line equation, the calculate G-value for 380 KeV was 1.542 µmol/J. Conclusion: The Result found for Ir-192 G-value is 3,1% different (lower) from the NRC value. But it agrees with previous literature results, using different methodologies to calculate this parameter. We will continue this experiment measuring the G-value for Co-60 in order to compare with the NRC method and better understand the reasons for the found differences.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Solcoseryl prevents early postradiation changes in the lungs.

    PubMed

    Starosławska, E; Chyczewski, L; Peszyński, J; Sobolewski, K; Bańkowski, E; Chyczewska, E; Nikliński, J; Donica, H; Kojtych, A

    1994-01-01

    The aim of the study was to test the influence of Solcoseryl on early postradiation changes in the lungs of rats. The chests of the rats were irradiated with Co-60, fractional dose 250 cGy/DT, total dose 2500 cGy/DT. Solcoseryl was given intraperitoneally in quantities of 0,1ml daily, during 60 days of the experiment. Morphological examinations of the lungs revealed that Solcoseryl decreased significantly the effects of early postradiation damage of the respiratory organ in rats.

  12. Use of polyvinylpyrrolidone-iodine solution for sterilisation and preservation improves mechanical properties and osteogenesis of allografts

    PubMed Central

    Zhao, Yantao; Hu, Xiantong; Li, Zhonghai; Wang, Fuli; Xia, Yang; Hou, Shuxun; Zhong, Hongbin; Zhang, Feimin; Gu, Ning

    2016-01-01

    Allografts eliminate the disadvantages associated with autografts and synthetic scaffolds but are associated with a disease-transmission risk. Therefore, allograft sterilisation is crucial. We aimed to determine whether polyvinylpyrrolidone-iodine (PVP-I) can be used for sterilisation and as a new wet-preservation method. PVP-I–sterilised and preserved allografts demonstrated improved mechanical property, osteogenesis, and excellent microbial inhibition. A thigh muscle pouch model of nude mice showed that PVP-I–preserved allografts demonstrated better ectopic formation than Co60-sterilised allografts (control) in vivo (P < 0.05). Furthermore, the PVP-I–preserved group showed no difference between 24 h and 12 weeks of allograft preservation (P > 0.05). PVP-I–preserved allografts showed more hydrophilic surfaces and PVP-I–sterilised tendons showed higher mechanical strength than Co60-sterilised tendons (P < 0.05). The level of residual PVP-I was higher without washing and with prolonged preservation (P < 0.05). In vitro cellular tests showed that appropriate PVP-I concentration was nontoxic to preosteoblast cells, and cellular differentiation measured by alkaline phosphatase activity and osteogenic gene markers was enhanced (P < 0.05). Therefore, the improved biological performance of implanted allografts may be attributable to better surface properties and residual PVP-I, and PVP-I immersion can be a simple, easy method for allograft sterilisation and preservation. PMID:27934929

  13. Metal removal from oil sands tailings pond water by indigenous micro-alga.

    PubMed

    Mahdavi, Hamed; Ulrich, Ania C; Liu, Yang

    2012-09-01

    This paper reports the removal of ten target metals of environmental concern ((53)Cr, Mn, Co, (60)Ni, (65)Cu, (66)Zn, As, (88)Sr, (95)Mo, and Ba) from oil sands tailings pond water. The organism responsible for removal was found to be an indigenous green micro-alga identified as Parachlorella kessleri by sequencing of the 23S rRNA gene. P. kessleri grew in tailings pond water samples taken from two oil sands operators (Syncrude Canada Ltd. and Albian Sands Energy Inc.), and enriched with low (0.24 mM NO(3)(-) and 0.016 mM PO(4)(-3)) and high (1.98 mM NO(3)(-) and 0.20mM PO(4)(-3)) concentrations of nutrient supplements (the most realistic scenario). The removal of (60)Ni, (65)Cu, As, (88)Sr, (95)Mo, and Ba from Syncrude tailings pond water was significantly enhanced by high concentrations of nitrogen and phosphorus, whereas the high nutrient concentrations adversely affected the removal of Co, (60)Ni, As, (88)Sr, and Mo in samples of Albian tailings pond water. Based on ANOVA two-factor analysis, higher nutrient concentration does not always result in higher metal removal, and TPW source must also be considered.

  14. 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.

  15. 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.

  16. [Side effects of postoperative irradiation of uterine cancer with high dose rate iridium and low dose rate radium].

    PubMed

    Kucera, H; Unel, N; Weghaupt, K

    1986-02-01

    A report is given about reversible and irreversible complications following postoperative irradiation in cases of endometrial carcinoma. Intravaginal brachytherapy was performed. In advanced cases or in cases with poor prognosis (tumor grading) percutaneous irradiation was added (Co60). In 156 cases low-dose-rate irradiation (Ra226) and in 143 cases high-dose-rate irradiation (Ir192) was applied intravaginally. Reversible complications (cystitis, proctitis) could be observed following Radium in 7%, following Iridium in 14%. Irreversible complications (fistulas, stenoses): 1.9% following Radium and 3.5% following Iridium. When high-dose-rate irradiation was combined with percutaneous Co60 therapy, reversible complications occurred in 22.8%. After changing the Iridium-therapy scheme (reduction of dose from 10 to 7 Gy and irradiation only of the upper two thirds of the vagina) complications only could be observed in the same level as in Radium-therapy. High-dose-rate irradiation does not need hospitalization of the patients.

  17. 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.

  18. 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%.

  19. In vitro evaluation of head and neck radiation shields used to reduce exit dose.

    PubMed

    Dirican, Bahar; Ozen, Julide; Beyzadeoglu, Murat; Oysul, Kaan; Surenkok, Serdar; Sipahi, Cumhur

    2006-01-01

    To determine the optimal thickness of protective oral radiation shields composed of an acrylic resin stent and a lead shield, which are used in head and neck radiotherapy to minimize undesired normal tissue radiomorbidity. Intraoral acrylic resin stents and lead shields of different thicknesses were inserted into a specially designed human mandible phantom with thermoluminescent lithium fluoride dosimeter chips (TLD-100) placed on the buccal and lingual sites and exposed to irradiation of different energies. Fifty-cGy irradiation was performed and TLD-100 dose measurements were obtained for each irradiation type, acrylic resin stent thickness, and lead shield thickness. Acrylic resin stents with a 2-mm lead shield reduced 20% and 15% of the normal tissue dose for Co-60 and 6 MV X photon radiations, respectively, whereas the stents with a 4-mm lead shield achieved a higher reduction of the normal tissue dose (30% and 23% for Co-60 and 6 MV X photons, respectively). In protective oral radiation shields, acrylic resin stent thickness has little effect on the reduction of normal tissue dose, but lead shield thickness significantly effects the reduction of normal tissue dose.

  20. 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.

  1. 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.

  2. 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)

  3. 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.

  4. Enhanced peroxidase activity and tumour tissue visualization by cobalt-doped magnetoferritin nanoparticles

    NASA Astrophysics Data System (ADS)

    Zhang, Tongwei; Cao, Changqian; Tang, Xu; Cai, Yao; Yang, Caiyun; Pan, Yongxin

    2017-01-01

    Magnetoferritin (M-HFn) is a biomimetic magnetic nanoparticle with a human heavy-chain ferritin (HFn) shell, trapping a magnetite (Fe3O4) core that has inherited peroxidase-like activity. In this study, cobalt-doped M-HFn nanoparticles (M-HFn-Co x Fe3-x O4) with different amounts of cobalt were successfully synthesized. Experimental results indicate that the controlled doping of a certain amount of cobalt into the magnetite cores of M-HFn nanoparticles enhances its peroxidase-like catalytic activity and efficacy for visualizing tumour tissues. For example, compared with sample Co0 (without cobalt doping), the peroxidase-like activity of the cobalt-doped nanoparticle sample Co60 (with a cobalt doping molar percentage of ˜34.2%) increases 1.7 times, and has the maximal reaction velocity (V max) values. Moreover, after a one-step incubation with Co60 nanoparticles, and using the peroxidase substrate 3,3‧-diaminobenzidine tetrahydrochloride (DAB) for colour development, the tumour tissues of breast, colorectal, stomach and pancreas tumours showed a deeper brown colour with clear boundaries between the healthy and tumourous cells. Therefore, this suggests that the cobalt-doped magnetoferritin nanoparticles enhance peroxidase activity and tumour tissue visualization.

  5. 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.

  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. 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.

  8. Partitioning and bioaccumulation of metals from oil sands process affected water in indigenous Parachlorella kessleri.

    PubMed

    Mahdavi, Hamed; Liu, Yang; Ulrich, Ania C

    2013-02-01

    This paper studies the partitioning and bioaccumulation of ten target metals ((53)Cr, Mn, Co, (60)Ni, (65)Cu, (66)Zn, As, (88)Sr, (95)Mo and Ba) from oil sands tailings pond water (TPW) by indigenous Parachlorella kessleri. To determine the role of extracellular and intracellular bioaccumulation in metal removal by P. kessleri, TPW samples taken from two oil sands operators (Syncrude Canada Ltd. and Albian Sands Energy Inc.) were enriched with nutrient supplements. Results indicate that intracellular bioaccumulation played the main role in metal removal from TPW; whereas extracellular bioaccumulation was only observed to some extent for Mn, Co, (60)Ni, (65)Cu, (88)Sr, (95)Mo and Ba. The FTIR scan and titration of functional groups on the cell surface indicated low metal binding capacity by indigenous P. kessleri. However, it is believed that the dissolved cations and organic ligand content in TPW (such as naphthenic acids) may interfere with metal binding on the cell surface and lower extracellular bioaccumulation. In addition, the total bioaccumulation and bioconcentration factor (BCF) varied during the cultivation period in different growth regimes.

  9. Optimum Water Chemistry in radiation field buildup control

    SciTech Connect

    Lin, Chien, C.

    1995-03-01

    Nuclear utilities continue to face the challenGE of reducing exposure of plant maintenance personnel. GE Nuclear Energy has developed the concept of Optimum Water Chemistry (OWC) to reduce the radiation field buildup and minimize the radioactive waste production. It is believed that reduction of radioactive sources and improvement of the water chemistry quality should significantly reduce both the radiation exposure and radwaste production. The most important source of radioactivity is cobalt and replacement of cobalt containing alloy in the core region as well as in the entire primary system is considered the first priority to achieve the goal of low exposure and minimized waste production. A plant specific computerized cobalt transport model has been developed to evaluate various options in a BWR system under specific conditions. Reduction of iron input and maintaining low ionic impurities in the coolant have been identified as two major tasks for operators. Addition of depleted zinc is a proven technique to reduce Co-60 in reactor water and on out-of-core piping surfaces. The effect of HWC on Co-60 transport in the primary system will also be discussed.

  10. Single fraction per day versus two fractions per day versus radiochemotherapy in the treatment of head and neck cancer.

    PubMed

    Sanchíz, F; Millá, A; Torner, J; Bonet, F; Artola, N; Carreño, L; Moya, L M; Riera, D; Ripol, S; Cirera, L

    1990-12-01

    From January 1978 to January 1988, 859 patients with T3-T4, NO-3, MO were randomly allocated to receive either: Group A--60Co 60, 60 Gy in 30 fractions; Group B--60Co, 70.4 Gy in 64 fractions; Group C--60Co, 60 Gy in 30 fractions plus chemotherapy (5 Fu, 250 mg/m2/IV every 2 days). Chemotherapy and radiotherapy were combined simultaneously. The average age was 56 years; the male/female ratio was 802/57. Median performance status (ECOG scale) was 1 (range 0-2). The TNM distribution as UICC criteria was T3 529 patients; T4 330 patients; No 217 patients; N1 52 patients; N2 319 patients; and N3 271 patients. The primary sites were nasopharynx 92, oral cavity 252, hypopharynx 119, larynx 310, and others (sinuses and unknown primary)86. Complete response was achieved in 188/277 patients in Group A (67.8%), 254/282 patients in Group B (90%), and 289/300 in Group C (96.3%). All patients were followed and statistical analysis shows a significant improvement in median duration of response, as well as survival for Groups B and C compared with Group A. No significant differences were seen between Group B and C. The acute toxicity was mucositis, skin toxicity, bone marrow depression. A mean temporary weight loss of 4.9 Kg was observed with a range of 2.3-10.5 Kg.

  11. Response of organic liquid scintillators to fast neutrons and gamma radiation

    NASA Astrophysics Data System (ADS)

    Hoertz, Paul G.; Mills, Karmann; Davis, Lynn; Baldasaro, Nicholas; Gupta, Vijay

    2013-03-01

    Liquid organic scintillators are cocktails of aromatic fluorophores in an aromatic solvent. They find widespread use in Liquid Scintillation Counters with applications in medical diagnostics as well as fundamental nuclear and particle physics. Ultima Gold™ XR, a commercially available organic liquid scintillator from Perkin Elmer, can be used in both aqueous and non-aqueous systems and is typically used for beta detection in medical diagnostics. Its performance under gamma radiation and neutron radiation is less well-characterized. Special and normal Ultima Gold™ XR liquid scintillators were exposed in separate experiments to fast neutrons and high energy photons from a nuclear reactor and to gamma rays from a Co-60 source. To perform the measurements in the radiation chamber, a custom light collection system consisting of a fiber optic cable, spectrometer and a diffuse reflecting optical cavity was fabricated. Advanced calibration procedures, traceable to NIST standards, were developed to determine photon fluxes and flux densities of the scintillators under ionizing radiation conditions. The scintillator emission spectra under gamma radiation from a Co-60 source and neutron radiation from a pool-type nuclear reactor were recorded and compared. Results on the spectrometer design and comparison of the spectra under different exposure are presented.

  12. Use of polyvinylpyrrolidone-iodine solution for sterilisation and preservation improves mechanical properties and osteogenesis of allografts

    NASA Astrophysics Data System (ADS)

    Zhao, Yantao; Hu, Xiantong; Li, Zhonghai; Wang, Fuli; Xia, Yang; Hou, Shuxun; Zhong, Hongbin; Zhang, Feimin; Gu, Ning

    2016-12-01

    Allografts eliminate the disadvantages associated with autografts and synthetic scaffolds but are associated with a disease-transmission risk. Therefore, allograft sterilisation is crucial. We aimed to determine whether polyvinylpyrrolidone-iodine (PVP-I) can be used for sterilisation and as a new wet-preservation method. PVP-I-sterilised and preserved allografts demonstrated improved mechanical property, osteogenesis, and excellent microbial inhibition. A thigh muscle pouch model of nude mice showed that PVP-I-preserved allografts demonstrated better ectopic formation than Co60-sterilised allografts (control) in vivo (P < 0.05). Furthermore, the PVP-I-preserved group showed no difference between 24 h and 12 weeks of allograft preservation (P > 0.05). PVP-I-preserved allografts showed more hydrophilic surfaces and PVP-I-sterilised tendons showed higher mechanical strength than Co60-sterilised tendons (P < 0.05). The level of residual PVP-I was higher without washing and with prolonged preservation (P < 0.05). In vitro cellular tests showed that appropriate PVP-I concentration was nontoxic to preosteoblast cells, and cellular differentiation measured by alkaline phosphatase activity and osteogenic gene markers was enhanced (P < 0.05). Therefore, the improved biological performance of implanted allografts may be attributable to better surface properties and residual PVP-I, and PVP-I immersion can be a simple, easy method for allograft sterilisation and preservation.

  13. 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.

  14. 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)

  15. 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…

  16. 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…

  17. 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…

  18. 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…

  19. 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…

  20. 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…