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Sample records for uranio previa extraccin

  1. Spectrophotometric Determination of Microamounts of Uranium previous Extraction with TBP-MIC; Determinacion Espectrofotometrica de Microcantidades de Uranio previa extraccin con Metilisobutilcetona-Fosfato de Tributilo

    Energy Technology Data Exchange (ETDEWEB)

    Vera Palomino, J; Palomares Delgado, F; Petrement, J; Fernandez Cellini, R

    1962-07-01

    Selective extraction of uranium in nitric acid medium with a mixture of Tbp-MIC (1:10) has been achieved. Aluminium nitrate was used as salting agent. Complexing agents were added in order to avoid extraction of impurities. Extraction conditions have been studied so that extraction is almost practically complete in a single run. (Author) 19 refs.

  2. Algunos complejos de carboxilatos de uranio (IV y 1-pirazolilborato

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    Omar Velasquez

    2009-07-01

    Full Text Available En este trabajo se presenta la síntesis y caracterización, mediante espectroscopia de infrarojo y H'—NMR de complejos de acetato de uranio, dietil carbamatos y dietilditiocarbamatos y 1—pirazolil—borato.

  3. CONTENUTO DI URANIO E TORIO NELLE METEORITI

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    M. SANTANGELO

    1955-06-01

    Full Text Available Molti ricercatori in questi ultimi anni si sono interessati al problema
    della composizione delle meteoriti; dai risultati sperimentali si
    è cercato trarre elementi circa la genesi di questi materiali, questione
    ancora aperta, ed avere informazioni sui processi chimici e termodinamici
    cui le meteoriti furono soggette prima della loro caduta sulla
    terra.
    Uno degli aspetti del problema è quello dell'abbondanza percentuale
    degli elementi chimici e della loro composizione isotopica nella
    materia meteorica dei diversi tipi : ciò perché esso è connesso con
    quello piii generale dell'origine e distribuzione degli elementi nel cosmo
    e nella terra, nonché con quello dell'età delle meteoriti (l .
    In un recente lavoro Urey e collaboratori (-, esaminando un gran
    numero di analisi chimiche effettuate su questi materiali, sono pervenuti
    alla formulazione di alcuni criteri di classificazione in base alla
    percentuale dei componenti più abbondanti ed alla presenza o meno
    di disomogeneità strutturali nella massa fondamentale. Fra gli elementi
    meno abbondanti presentano particolare interesse quelli delle due famiglie
    radioattive naturali Torio e Uranio; le loro concentrazioni sono
    state determinate per alcune meteoriti siliciche (stonv ineteorites e
    per qualcuna ferrica (iron meteorites

  4. Consulta previa y democracia en el Ecuador

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    Floresmilo Simbaña

    2012-11-01

    Full Text Available Este artículo aborda un tema clave respecto de la efectiva participación política de los pueblos indígenas: el derecho a la Consulta Previa. En el Ecuador, la Constitución establece que el Estado tiene que consultar a las comunidades antes de poner en marcha iniciativas de desarrollo que podrían afectarlas directamente. No obstante, esa obligación ha sido sistemáticamente eludida por diversos gobiernos y los pueblos indígenas se han visto obligados a acudir a las instancias internacionales de protección de los derechos humanos para hacer respetar sus derechos. Tal es el caso del pueblo kichwa de Sarayaku. El autor ofrece un panorama de esa lucha histórica.

  5. [Management of placenta previa and accreta].

    Science.gov (United States)

    Kayem, G; Keita, H

    2014-12-01

    Produce recommendations for the management of placenta previa and placenta accrete. A literature search was conducted using Medline and the Cochrane Library over a period from 1950 to 31/12/2013. Recommendations of the latest scientific societies have also been consulted. In cases of placenta previa, if bleeding episode before 34weeks gestation occurs, a short hospitalization and tocolysis may help stop bleeding (grade C). Vaginal delivery is preferable when the distance between the internal cervical os and the placental edge is greater than 20mm. When this distance is less than 20mm, vaginal delivery is possible (professional consensus). Caesarean section is recommended in cases of placenta overlapping the internal os (professional consensus). Antenatal screening placenta accreta could improve care (EL3). Upon discovery of a placenta accreta during childbirth, it is better to avoid a forced removal of the placenta (grade C). Conservative treatment or cesarean hysterectomy are possible (grade C). The management of placental abnormalities should be planned and managed with a multidisciplinary team (professional consensus). The use of blood-saving techniques such as "cell saver" is possible in situations where early intraoperative bleeding would be>1500mL (grade C). There are no studies that have sufficient methodological value to recommend an anesthetic technique [general anaesthesia (GA) or neuraxial anaesthesia] over another in the context of placental abnormalities (grade B). When a major bleeding risk is identified, GA can be chosen in order to avoid emergency conversions in difficult conditions (professional consensus). Placental insertion abnormalities require anesthetic and obstetric coordination. Delivery must be planned in a suitable structure. Copyright © 2014. Published by Elsevier Masson SAS.

  6. Anesthesia for cesarean section in pregnancies complicated by placenta previa

    International Nuclear Information System (INIS)

    Imarengiaye, Charles O.; Osaigbovo, Etinosa P.; Tudjegbe, Sampson O.

    2008-01-01

    Objective was to evaluate the factors affecting the choice of anesthetic technique for cesarean section in women with placenta previa. In this retrospective study, the records of the labor Ward Theatre of the University of Benin Teaching Hospital, Benin City, Nigeria were examined from January 2000 to December 2004 to identify all the women who had cesarean section for placenta previa. The patient's socio-demographic characteristics, type of placenta previa, anesthesia technique, estimated blood loss, maternal and fetal outcomes were recorded. One hundred and twenty-six patients had cesarean section for placenta previa, however, only 81 patients 64.3% were available for analysis. General anesthesia was administered to 52/81 patients 64.2% and 29/81 patients 35.8% received spinal anesthesia. A history of antepartum bleeding was recorded in 61.7% n=50. Of 31 patients without antepartum hemorrhage APH, 15/31 had general anesthesia and 16/31 had spinal anesthesia. The patients who had APH, 37/50 had general anesthesia and 1/50 had spinal anesthesia. There was an increased chance of using general anesthesia and if APH were present p=0.03, odds ratio=3.1, 95% confidence interval=1.2-7.7. Spinal anesthesia may useful in patients with placenta previa. The presence of APH may encourage the use of general anesthesia for cesarean delivery. (author)

  7. The cervix as a natural tamponade in postpartum hemorrhage caused by placenta previa and placenta previa accreta: a prospective study.

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    El Gelany, Saad A A; Abdelraheim, Ahmed R; Mohammed, Mo'men M; Gad El-Rab, Mohammed T; Yousef, Ayman M; Ibrahim, Emad M; Khalifa, Eissa M

    2015-11-11

    Placenta previa and placenta accreta carry significant maternal and fetal morbidity and mortality. Several techniques have been described in the literature for controlling massive bleeding associated with placenta previa cesarean sections. The objective of this study was to evaluate the efficacy and safety of the use of the cervix as a natural tamponade in controlling postpartum hemorrhage caused by placenta previa and placenta previa accreta. This prospective study was conducted on 40 pregnant women admitted to our hospital between June 2012 and November 2014. All participating women had one or more previous cesarean deliveries and were diagnosed with placenta previa and/or placenta previa accreta. Significant bleeding from the placental bed during cesarean section was managed by inverting the cervix into the uterine cavity and suturing the anterior and/or the posterior cervical lips into the anterior and/or posterior walls of the lower uterine segment. The technique of cervical inversion described above was successful in stopping the bleeding in 38 out of 40 patients; yielding a success rate of 95%. We resorted to hysterectomy in only two cases (5%). The mean intra-operative blood loss was 1572.5 mL, and the mean number of blood units transfused was 3.1. The mean time needed to perform the technique was 5.4 ± 0.6 min. The complications encountered were as follows: bladder injury in the two patients who underwent hysterectomy and wound infection in one patient. Postoperative fever that responded to antibiotics occurred in 1 patient. The mean duration of the postoperative hospital stay was 3.5 days This technique of using the cervix as a natural tamponade appears to be safe, simple, time-saving and potentially effective method for controlling the severe postpartum hemorrhage (PPH) caused by placenta previa/placenta previa accreta. This technique deserves to be one of the tools in the hands of obstetricians who face the life-threatening hemorrhage of placenta

  8. Presence of URAMEX (Uranio Mexicano) in Mexico's development

    International Nuclear Information System (INIS)

    1980-01-01

    The purpose of this work is to inform the Government and the Nation about the achievements and experiences of Uranio Mexicano (URAMEX, sole agent of the State in the uranium exploration, exploitation and commercialization), as well as the context in which the uranium production evolves, supporting the growth of the electric power utility through nuclear energy, and making easier the decrease in the use of hydrocarbons as a source of energy. Through this work we know about the main activity of URAMEX, which is the elaboration of uranium concentrate, raw material of the nuclear reactor, based on the technological requirements of the exploration, exploitation, milling of uranium ore and the nuclear fuel cycle in general. To reach these objectives the uranium industry depends on the rhythm of expansion in the electrical sector, the productive sectors in general, and on the resources URAMEX disposes to reach its goals which are strictly related to the establishment of an integrated nuclear power industry that will greatly contribute to the independent development of the country. This work intends to design the development of the uranium processing according to the extractive industry politics of the ''Plan Nacional de Desarrollo Industrial'' (National Plan for Industrial Development) promulgated in 1979. In this Plan the operations of URAMEX are designed in agreement with the projections of the expected development in the electrical sector and specially in the nuclear power electricity. (author)

  9. The role of shear wave elastography in the assessment of placenta previa-accreta.

    Science.gov (United States)

    Alıcı Davutoglu, Ebru; Ariöz Habibi, Hatice; Ozel, Ayşegül; Yuksel, Mehmet Aytac; Adaletli, Ibrahim; Madazlı, Riza

    2018-06-01

    To evaluate the value of shear wave elastography (SWE) in the prediction of morbidly adherent placenta. Forty-three women with normal placental location and 26 women with anteriorly localized placenta previa were recruited for this case-control study. Placental elasticity values in both the groups were determined by SWE imaging. SWE values were higher in the placenta previa group in all regions than in normal localized placentas (p  .05). Placental stiffness is significantly higher in placenta previa than normal localized placentas. However, we could not demonstrate any statistically significant difference in the elasticity values between the placenta previa with and without accreta.

  10. Static leaching of Spanish uranium ores; Lixiviacion estatica de minerales espanoles de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Cordero, G; Gasos, P; Merino, J L; Suarez, Y E [Direccion de Plantas Piloto e Industriales, Junta de Energia Nuclear, Madrid (Spain)

    1967-06-15

    The paper summarizes the experience acquired in Spain during seven years of investigation on the static leaching of uranium ores. The operations covered minerals showing wide variations with regard to both uranium content (250 and 2000 ppm) and the type of rock and gangue (granites, shales, sandstones, sulphides, carbonates, limonites etc.). The studies were carried out on quantities of material varying from a few kilograms to several tons. Leaching agents included water, solid reagents (pyrites), alkaline carbonates and sulphuric acid. The systems used consisted of both simple layouts and other, more elaborate schemes including recycling of the liquors. The uranium was recovered from the liquors first by direct precipitation and later by ion-exchange and extraction with amines. (author) [Spanish] La memoria resume la experiercia espanola de siete anos de estudio sobre lixiviacion estatica de minerales de uranio. Se ha estudiado una gran variedad de minerales tanto en lo que respecta a ley de uranio (250 y 2000 ppm), como a la naturaleza de las rocas y gangas (granitos, pizarras, areniscas, sulfuros, carbonatos, limonitas, etc.). Los estudios se han realizado en diferentes escalas, desde kilogramos a varias toneladas. Los agentes de lixiviacion han sido variables: agua, reactivos solidos (piritas), carbonatos alcalinos y acido sulfurico. Los circuitos empleados se refieren tanto a esquemas sencillos, como a otros mas elaborados con recirculaciones de liquido. La recuperacion del uranio de los liquidos se resolvio inicialmente por precipitacion directa, pero luego se efectuo mediante cambio de ion y extraccion con aminas. (author)

  11. Placenta previa; MRI as an adjunct to ultrasound in assessment of suspected placental invasion

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    Asmaa M. Abdel Magied

    2018-03-01

    Full Text Available Objective: Evaluate adding MRI to ultrasound in imaging of placenta previa with suspected placenta accreta. Patients and methods: evaluation of 23 pregnant females presenting with placenta previa was done. The age ranged from 20 to 39 years (mean = 30.9. All of the patients were subjected to ultrasonography (US and magnetic resonance imaging (MRI of the pelvis at gestational age of 25–37 weeks prior to elective delivery. Results: 11 out of 23 patients were proved placenta accreta based on surgical and pathological reports. US suggested diagnosis of placenta previa/accreta in 8 patients and placenta previa without accreta in 15 cases. 7/8 was true positive (87.5% & one was false positive (12.5% with sensitivity 63.64%, accuracy 78.26%, and specificity 91.67%. MRI has suggested diagnosis of placenta previa/accreta in 8/23 & placenta previa with no accreta in 15/23 patients. MRI was found to give true positive results in 8/8 patients proved to be accreta. MRI gave true negative in 12 patients (80% & false negative in 3 (20% with sensitivity 72.73%, accuracy 86.96%, and specificity 100%. Conclusion: Combining MRI and ultra sound provide more diagnostic information and may reduce unnecessary interventions with favorable outcome. Keywords: Ultra sound, MRI, Placenta previa, Placenta accreta

  12. Placenta previa and risk of major congenital malformations among singleton births in Finland.

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    Kancherla, Vijaya; Räisänen, Sari; Gissler, Mika; Kramer, Michael R; Heinonen, Seppo

    2015-06-01

    Placenta previa has been associated with adverse birth outcomes, but its association with congenital malformations is inconclusive. We examined the association between placenta previa and major congenital malformations among singleton births in Finland. We performed a retrospective population register-based study on all singletons born at or after 22+0 weeks of gestation in Finland during 2000 to 2010. We linked three national health registers: the Finnish Medical Birth Register, the Hospital Discharge Register, and the Register of Congenital Malformations, and examined several demographic and clinical characteristics among women with and without placenta previa, in association with major congenital malformations. We estimated adjusted odds ratios and 95% confidence intervals using multivariable logistic regression models. The prevalence of placenta previa was estimated as 2.65 per 1000 singleton births in Finland (95% confidence interval, 2.53-2.79). Overall, 6.2% of women with placenta previa delivered a singleton infant with a major congenital malformation, compared with 3.8% of unaffected women (p ≤ 0.001). Placenta previa was positively associated with almost 1.6-fold increased risk of major congenital malformations in the offspring, after controlling for maternal age, parity, fetal sex, smoking, socio-economic status, chorionic villus biopsy, In vitro fertilization, pre-existing diabetes, depression, preeclampsia, and prior caesarean section (adjusted odds ratio = 1.55; 95% confidence interval, 1.27-1.90). Using a large population-based study, we found that placenta previa was weakly, but significantly associated with an increased risk of major congenital malformations in singleton births. Future studies should examine the association between placenta previa and individual types of congenital malformations, specifically in high-risk pregnancies. © 2015 Wiley Periodicals, Inc.

  13. A comparison of morbidity associated with placenta previa with and without previous caesarean sections

    International Nuclear Information System (INIS)

    Baqai, S.; Siraj, A.; Noor, N.

    2018-01-01

    To compare the morbidity associated with placenta previa with and without previous caesarean sections. Study Design: Retrospective comparative study. Place and Duration of Study: From March 2014 till March 2016 in the department of Obstetrics and Gynaecology at PNS Shifa hospital Karachi. Material and Methods: After the approval from hospital ethical committee, antenatal patients with singleton pregnancy of gestational age >32 weeks, in the age group of 20-40 years diagnosed to have placenta previa included in the study. All patients with twin pregnancy less than 20 years and more than 40 years of age were excluded. The records of all patients fulfilling the inclusion criteria were reviewed. Data had been collected for demographic and maternal variables, placenta previa, history of previous lower segment caesarean section (LSCS), complications associated with placenta previa and techniques used to control blood loss were recorded. Results: During the study period, 6879 patients were delivered in PNS Shifa, out of these, 2060 (29.9%) had caesarean section out of these, 47.3% patients had previous history of LSCS. Thirty three (1.6%) patients were diagnosed to have placenta previa and frequency of placenta previa was significantly higher in patients with previous history of LSCS than previous normal delivery of LSCS i.e. 22 vs. 11 (p=0.023). It was observed that the frequency of morbidly adherent placenta (MAP) and Intensive care unit (ICU) stay were significantly higher in patients with previous history of LSCS than previous history of normal delivery. Conclusion: Frequency of placenta previa was significantly higher in patients with history of LSCS. Also placenta previa remains a major risk factor for various maternal complications. (author)

  14. Risk Factors and Consequent Outcomes of Placenta Previa: Report From a Referral Center

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    Soraya Saleh Gargari

    2016-12-01

    Full Text Available  Because of an unknown factor, the frequency of complicated pregnancy with placenta previa has been raised during past decade. This study was designed to deepen our understanding of risk factors and outcomes of placenta previa in our country. This study investigated 694 cases of placenta previa comparing with 600 healthy pregnant women with not overlie placenta in two referral and tertiary Obstetrics and Gynecological Hospital in Iran on the basis of the clinical and para-clinical analysis, in order to find the probable risk factors for occurrence of placenta previa and its effect on maternal and neonatal complications. The most important risk factor for the occurrence of placenta previa was advanced maternal age (P<0.001 and history of stillbirth (OR=117.2, CI=58.3-236.0. In the other hand, the most substantial outcome of this disorder was a reduction of gestational age (P<0.001 and low birth weight neonatally (P<0.001. The conservative follow-up should be programmed for women with placenta previa based on the type of risk factors which can provide the best possible management to decrease the morbidity and mortality of their related complications.

  15. Efficacy and Safety of Prophylactic Uterine Artery Embolization in Pregnancy Termination with Placenta Previa

    Energy Technology Data Exchange (ETDEWEB)

    Pei, Renguang, E-mail: mediprg@bjmu.edu.cn; Wang, Guoxiang; Wang, Heping; Huang, Xinyu; Yan, Xiaoxing; Yang, Xiaohua [Yijishan Hospital of Wannan Medical College, Department of Interventional Therapy (China)

    2017-03-15

    PurposeTo appraise the efficacy and safety of prophylactic uterine artery embolization in pregnancy termination with placenta previa.MethodsA cohort of 54 consecutive patients with placenta previa underwent prophylactic uterine artery embolization before vaginal delivery from February 2012 to March 2015. Vaginal delivery was attempted in all patients. Cesarean section or hysterectomy was introduced when vaginal delivery failed.ResultsVaginal delivery succeeded in 50 patients (93.6%) and failed in 4 patients (6.4%), thereupon converted to cesarean delivery. No patients resorted to hysterectomy. Six patients (11.1%) underwent blood transfusion. None of clinical characteristics, including maternal age, gestational age, history of abortion, history of cesarean delivery, and volume of vaginal bleeding, was significantly associated with complete placenta previa (P > 0.05). However, patients with complete placenta previa had a significantly lower successful rate of vaginal delivery than did patients without complete placenta previa (81 vs 100%, P = 0.038). The rate of complications was 3.7%. No major complications were observed.ConclusionUterine artery embolization is an effective and safe technique to assist pregnancy termination with placenta previa, which may lower the risk of cesarean section, hysterectomy, and blood transfusion.

  16. Efficacy and Safety of Prophylactic Uterine Artery Embolization in Pregnancy Termination with Placenta Previa

    International Nuclear Information System (INIS)

    Pei, Renguang; Wang, Guoxiang; Wang, Heping; Huang, Xinyu; Yan, Xiaoxing; Yang, Xiaohua

    2017-01-01

    PurposeTo appraise the efficacy and safety of prophylactic uterine artery embolization in pregnancy termination with placenta previa.MethodsA cohort of 54 consecutive patients with placenta previa underwent prophylactic uterine artery embolization before vaginal delivery from February 2012 to March 2015. Vaginal delivery was attempted in all patients. Cesarean section or hysterectomy was introduced when vaginal delivery failed.ResultsVaginal delivery succeeded in 50 patients (93.6%) and failed in 4 patients (6.4%), thereupon converted to cesarean delivery. No patients resorted to hysterectomy. Six patients (11.1%) underwent blood transfusion. None of clinical characteristics, including maternal age, gestational age, history of abortion, history of cesarean delivery, and volume of vaginal bleeding, was significantly associated with complete placenta previa (P > 0.05). However, patients with complete placenta previa had a significantly lower successful rate of vaginal delivery than did patients without complete placenta previa (81 vs 100%, P = 0.038). The rate of complications was 3.7%. No major complications were observed.ConclusionUterine artery embolization is an effective and safe technique to assist pregnancy termination with placenta previa, which may lower the risk of cesarean section, hysterectomy, and blood transfusion.

  17. Rovesciamento e alterazione nei racconti Uranio, Vanadio e in Auschwitz, Città Tranquilla

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    Fausto Maria Greco

    2016-11-01

    Full Text Available Ne Il sistema periodico accade che i processi dell’alterazione e del rovesciamento investano le funzioni stesse della narrazione e della testimonianza. In Uranio il personaggio di Bonino, narratore inattendibile, è un doppio rovesciato di Primo Levi. Egli realizza uno degli incubi dello scrittore torinese, quello di raccontare l’esperienza vissuta nel lager e di non essere creduto, ma l’effetto di rovesciamento riguarda anche altri versanti della scrittura. Come Elie Wiesel nel racconto intitolato Barbara, incluso nella raccolta de L’ebreo errante del 1966, Levi prende le distanze, in Uranio, da una memoria che falsifica, che oltrepassa la barriera della verità per costruire un’immagine eroica dei sopravvissuti. Nell’opera di Levi le figure di doppi rovesciati segnalano rischi incombenti, ipotesi inquietanti; i processi di alterazione, invece, si adattano meglio allo sforzo di conoscenza che riguarda l’universo concentrazionario. In questo rapporto stanno il Bonino di Uranio e il Cerrato di Argento, il dottor Müller di Vanadio (ancora ne Il sistema periodico e l’ingegner Mertens del racconto di Auschwitz, città tranquilla (pubblicato nell’84 e aggiunto ai Racconti e saggi. Dietro i nomi di Müller e di Mertens si celano, però, figure in carne e ossa con le quali lo scrittore è entrato in contatto. Il capovolgimento rivela un’ipotesi provocatoria, una vertigine del pensiero, nel caso di Mertens; l’alterazione apre alla conoscenza etica nella vicenda di Müller.The study focuses on the methods of alteration and overturning that influence functions of narration and testimony in Primo Levi’s Il sistema periodico (1975. In the short story Uranio, the character of Bonino is an unreliable storyteller as well as an overturned double of the writer. Bonino represents one of Levi’s obsessions, i.e., not being believed when telling the experience of prison and extermination camps. The effect of overturning also regards

  18. Validation of the Preverbal Visual Assessment (PreViAs) questionnaire.

    Science.gov (United States)

    García-Ormaechea, Inés; González, Inmaculada; Duplá, María; Andres, Eva; Pueyo, Victoria

    2014-10-01

    Visual cognitive integrative functions need to be evaluated by a behavioral assessment, which requires an experienced evaluator. The Preverbal Visual Assessment (PreViAs) questionnaire was designed to evaluate these functions, both in general pediatric population or in children with high risk of visual cognitive problems, through primary caregivers' answers. We aimed to validate the PreViAs questionnaire by comparing caregiver reports with results from a comprehensive clinical protocol. A total of 220 infants (visual development, as determined by the clinical protocol. Their primary caregivers completed the PreViAs questionnaire, which consists of 30 questions related to one or more visual domains: visual attention, visual communication, visual-motor coordination, and visual processing. Questionnaire answers were compared with results of behavioral assessments performed by three pediatric ophthalmologists. Results of the clinical protocol classified 128 infants as having normal visual maturation, and 92 as having abnormal visual maturation. The specificity of PreViAs questionnaire was >80%, and sensitivity was 64%-79%. More than 80% of the infants were correctly classified, and test-retest reliability exceeded 0.9 for all domains. The PreViAs questionnaire is useful to detect abnormal visual maturation in infants from birth to 24months of age. It improves the anamnesis process in infants at risk of visual dysfunctions. Copyright © 2014. Published by Elsevier Ireland Ltd.

  19. Radón y sus efectos en la salud en trabajadores de minas de uranio

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    Gonzalo Aicardi-Carrillo

    2015-03-01

    Full Text Available Introducción: El radón es un gas presente en subsuelo, especialmente en minas de uranio, que produce consecuencias sobre la salud, entre las que destaca el cáncer de pulmón. En EEUU es la segunda causa de mortalidad por esta enfermedad. Pese a la fuerte relación causal no existe normativa específica europea de regulación en mineros. Objetivos: Identificar el efecto del radón y sus derivados sobre la salud de los trabajadores de minas de uranio; describir la asociación entre exposición a radón y a otros minerales sobre la salud y asociación entre radón y consumo de tabaco. Metodología: Realizamos una revisión bibliográfica de literatura publicada entre 2007 y 2014, en bases de datos biomédicas, utilizando los criterios de inclusión y exclusión previamente establecidos. Resultados: Se revisan 32 artículos, encontrando un aumento significativo de cáncer pulmonar (SMR-2.03, IC95% 1.96-2.10, incluso a dosis bajas (300-WLM así como otros cánceres (laringe, gástrico, hepático y leucemia y enfermedades cerebrovasculares, controlando posibles factores de confusión (tabaco, silicosis, cuarzo y arsénico no encontrando relación significativa ni sinergias. Conclusión: Existe asociación entre la exposición al radón y cáncer pulmonar en minas de uranio, con un periodo medio de latencia de 20 años, determinado por la dosis de radón y el tiempo de exposición. No se ha demostrado riesgo de desarrollar otros tipos de tumores, y los estudios que lo sugieren son poco consistentes.

  20. Spanish radioactive lignites, nature and solubility of the uranium; Lignitos radiactivos espanoles, naturaleza y solubilizacion del uranio

    Energy Technology Data Exchange (ETDEWEB)

    Josa, J M; Merino, J L; Villoria, A [Direccion de Plantas Piloto e Industriales, Junta de Energia Nuclear, Madrid (Spain)

    1967-06-15

    The authors describe the features of some 70 samples of radioactive lignites from various places in Spain (Huesca, Lerida, Teruel, Galicia and Murcia) with uranium contents varying between 20 and 1200 ppm. They carried out experiments on extraction of the uranium from these ores both by direct treatment and after roasting to eliminate organic matter and bring about concentration. The acid method was considered for leaching of the uranium from the substances in question using agitation and static bed techniques. Investigations were also carried out on the effect of the variables represented by grain size, amount of acid, temperature time and oxidants, in addition to those involved in the roasting process. (author) [Spanish] Los autores presentan las caracteristicas de unas 70 muestras de lignitos radiactivos procedentes de distintos puntos de Espana (Huesca, Lerida, Teruel, Galicia y Murcia) con leyes de uranio comprendidas entre 20 y 1200 ppm. El beneficio del uranio de estos minerales se ha abordado por tratamiento directo y despues de someterlos a tostacion, lo que elimino la materia organica y produjo enriquecimiento. La lixiviacion del uranio de los productos indicados se considero por via acida, utilizando tecnicas de agitacion y de lecho estatico. Se investigo la influencia de las variables tamano de grano, dosis de acido, temperatura, tiempo y oxidante, ademas de las implicadas en los procesos de tostacion. (author)

  1. Rising frequency of placenta previa and associated morbidity in women with previous casearean section

    International Nuclear Information System (INIS)

    Akhter, F.; Nawaz, Q.; Mushtaq, Q.U.A.

    2015-01-01

    To determine rising frequency of placenta previa and its associated morbidity in women with previous caesarean section. Study Design: Cross sectional study. Place and Duration of Study: This study was conducted in the Department of Obstetrics and Gynecology at CMH Kohat from Jul 2010 to Jun 2011. Patients and Methods: This study included all pregnant women undergoing repeat caesarean sections. Of these, total 74 patients were admitted with placenta previa. The frequency and associated morbidity were determined. Results: In our study 74 patients with placenta previa were included. 71.62% were less than 35 yrs of age, while 28.38% were equal to or more than 35 years. The gestational age at presentation was 24-36 weeks in 74.3% and 37 + weeks in 5.7% at presentation, 89% patients were symptomatic and 11% were asympyomatic. The morbidities observed were placenta accrete 47%, urinary tract trauma in 63.51%, caesarean hysterectomy in 62.16%, post operative febrile morbidity in 77.03%, maternal mortality was nil, paralytic ileus in 28.38%, PPH in 82.43%, surgical site infection in 16.21%. Conclusion: Frequency of placenta previa and its associated morbidity was raised due to repeated caesarean section rate which must be reduced to decrease maternal morbidity and mortality. (author)

  2. A danish national cohort study on neonatal outcome in singleton pregnancies with placenta previa

    DEFF Research Database (Denmark)

    Nørgaard, Lone N; Pinborg, Anja; Lidegaard, Ojvind

    2012-01-01

    . Main outcome measures. Gestational age, birthweight, Apgar score after 5min, stillbirth, neonatal mortality and admittance to neonatal intensive care unit. Results. The incidence of placenta previa in Denmark was 0.54% in 2006. Neonates born after pregnancies with placenta previa had a higher risk...... of being born at a gestational age below 37 weeks (OR 8.6; 95% CI 7.5-9.9), having Apgar score =7 at 5 min (OR 2.7; 95% CI 2.0-3.7), being transferred to neonatal intensive care unit (OR 4.3; 95% CI 3.8-4.9) and for stillbirth and neonatal mortality combined (OR 1.8; 95% CI 1.1-3.0), compared to neonates...... born in pregnancies without placenta previa. No increased risk of being small-for-gestational age was found (OR 1.0; 95% CI 1.0-1.2). Conclusion. When adjusting for confounders neonates born after pregnancies with placenta previa had a significantly higher risk of being born preterm, having a low Apgar...

  3. Efficacy of Intrauterine Bakri Balloon Tamponade in Cesarean Section for Placenta Previa Patients.

    Directory of Open Access Journals (Sweden)

    Hee Young Cho

    Full Text Available The aims of this study were to analyze the predictive factors for the use of intrauterine balloon insertion and to evaluate the efficacy and factors affecting failure of uterine tamponade with a Bakri balloon during cesarean section for abnormal placentation.We reviewed the medical records of 137 patients who underwent elective cesarean section for placenta previa between July 2009 and March 2014. Cesarean section and Bakri balloon insertion were performed by a single qualified surgeon. The Bakri balloon was applied when blood loss during cesarean delivery exceeded 1,000 mL.Sixty-four patients (46.7% required uterine balloon tamponade during cesarean section due to postpartum bleeding from the lower uterine segment, of whom 50 (78.1% had placenta previa totalis. The overall success rate was 75% (48/64 for placenta previa patients. Previous cesarean section history, anterior placenta, peripartum platelet count, and disseminated intravascular coagulopathy all significantly differed according to balloon success or failure (all p<0.05. The drainage amount over 1 hour was 500 mL (20-1200 mL in the balloon failure group and 60 mL (5-500 mL in the balloon success group (p<0.01.Intrauterine tamponade with a Bakri balloon is an adequate adjunct management for postpartum hemorrhage following cesarean section for placenta previa to preserve the uterus. This method is simple to apply, non-invasive, and inexpensive. However, possible factors related to failure of Bakri balloon tamponade for placenta previa patients such as prior cesarean section history, anterior placentation, thrombocytopenia, presence of DIC at the time of catheter insertion, and catheter drainage volume more than 500 mL within 1 hour of catheter placement should be recognized, and the next-line management should be prepared in advance.

  4. Antenatal Sonographic Diagnosis and Clinical Significance of Placenta Previa Accreta after Cesarean Section.

    Science.gov (United States)

    Liu, Zhen-Zhen; Wei, Yao; Wang, Ruo-Jiao; Xu, Wen; Shi, Zhi-Min; Dai, Qing

    2017-10-30

    Objective To investigate the clinical and antenatal sonographic characteristics of placenta previa accreta after cesarean section. Methods The data of 21 inpatients diagnosed as placenta previa accreta after cesarean section in PUMC Hospital from 2006 to 2016 were retrospectively reviewed. The clinical and ultrasound features were recorded and compared among three placental accreta groups,including placenta accrete group(n=5),increta group(n=12),and percreta group(n=4). The relationship between the placental thickness at the uterine anterior lower segment level and the blood loss of the following cesarean section was tested. Results Of 21 patients,placenta previa was diagnosed by ultrasound in 20 cases(95.2%) and placenta previa accreta was diagnosed in 9 cases(42.9%). Antenatal ultrasound findings included following signs:loss of "clear zone"(15/18,83.3%),myometrial thinning(12/18,66.7%),abnormal placental lacunae(12/19,63.2%),bladder wall interruption(2/18,11.1%),and uterovesical hypervascularity(4/9,44.4%). Myometrial thinning(J-T=64.000,P=0.036),abnormal placental lacunae(J-T=74.500,P=0.032) and the placental thickness at the uterine anterior lower segment level(U=83.000,P=0.010) showed significant difference among different placenta accreta groups. Placental thickness at the uterine anterior lower segment level showed linear correlation with the blood loss of the following cesarean section(r=0.669,P=0.002). The blood loss of the following cesarean section showed significant difference among different placenta accreta groups(U=118.500,P=0.000). Conclusions The clinical and sonographic manifestations of placenta previa accreta after cesarean section show a spectrum of demographic characteristics. The measurement of thickness of placenta at the anterior lower segment may help the evaluation of the clinical prognosis of this special pathology.

  5. Consulta previa en casos de minería para comunidades indígenas y tribales

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    Claudia Jimena Abello

    2012-12-01

    Full Text Available Este artículo hace un recorrido sobre la jurisprudencia de la Corte Constitucional sobre consulta previa y la minería. El objetivo es establecer las principales reglas, que ha creado la Corte al ponderar el derecho a la consulta previa versus el derecho del Estado a la explotación de recursos naturales. También, se intentará dar un esvoso de lo que entiende la Corte Constitucional como consulta previa y el procedimiento a seguir. Finalmente se hace una pequeña reflexión sobre el multiculturalismo y los derechos diferenciales.

  6. [Severe Adverse Pregnancy Outcomes in Placenta Previa and Prior Cesarean Delivery].

    Science.gov (United States)

    Zhou, Mi; Chen, Meng; Zhang, Li; He, Guo-Lin; He, Lei; Wei, Qiang; Li, Tao; Liu, Xing-Hui

    2017-09-01

    To investigate the severe adverse pregnancy outcomes in pregnancies with placenta previa and prior cesarean delivery and its risk factors. This retrospective casecontrol study reviewed all pregnancies with placenta previa and prior cesarean delivery delivered by repeat cesarean section in our institution between January 2005 and June 2015,and investigated the incidence of severe adverse pregnancy outcome. A composite of severe adverse pregnancy outcomes (including transfusion of 10 units or more red blood cells,maternal ICU admission,unanticipated injuries,repeat operation,hysterectomy,and maternal death) and other maternal and neonatal outcomes were described. Univariate and multivariable logistic regression analysis were used to quantify the effects of risk factors on severe adverse pregnancy outcomes. There were 478 women with placenta previa and prior cesarean delivery in our hospital over the last decade. The average age of them was 32.5±4.8 years old,most women were beyond 30 years old,the average gravidity and parity were 4 and 1,131 cases (27.4%) had severe adverse pregnancy outcomes. Transfusion of 10 units or more red blood cells happened in 75 cases (15.7%,75/478); 44 cases (9.2%,44/478) necessitated maternal ICU admission; unanticipated bladder injury occurred in 11 cases,but non ureter or bowel injury happened; All 4 repeat operations were due to delayed hemorrhage after conservative management during cesarean delivery,and an emergent hysterectomy was performed for all of the 4 cases. Hysterectomy (107 cases,22.4%) was the most common severe adverse pregnancy outcome. Among all 311 morbidly adherent placenta cases finally confirmed by pathological or surgical findings or both,only 172 (55.3%) were suspected before delivery. Multivariable logistic regression analysis showed that the risk of severe adverse pregnancy outcomes was significantly increased by pernicious placenta previa (i.e. anterior placenta overlying the prior cesarean scar),suspicion of

  7. Placenta Accreta and Total Placenta Previa in the 19th Week of Pregnancy

    Science.gov (United States)

    Findeklee, S.; Costa, S. D.

    2015-01-01

    Placentation disorders are the result of impaired embedding of the placenta in the endometrium. The prevalence of these disorders is estimated to be around 0.3 %. A history of previous prior uterine surgery (especially cesarean section and curettage) is the most common risk factor. Impaired placentation is differentiated into deep placental attachment; marginal, partial and total placenta previa; and placenta accreta, increta and percreta. Treatment depends on the severity of presentation and ranges from expectant management to emergency hysterectomy. In most cases, preterm termination of pregnancy is necessary. We report here on the case of a 39-year-old woman with placenta accreta and total placenta previa who underwent hysterectomy in the 19th week of pregnancy. PMID:26366004

  8. Vasa previa screening strategies: a decision and cost-effectiveness analysis.

    Science.gov (United States)

    Sinkey, R G; Odibo, A O

    2018-05-22

    The aim of this study is to perform a decision and cost-effectiveness analysis comparing four screening strategies for the antenatal diagnosis of vasa previa among singleton pregnancies. A decision-analytic model was constructed comparing vasa previa screening strategies. Published probabilities and costs were applied to four transvaginal screening scenarios which occurred at the time of mid-trimester ultrasound: no screening, ultrasound-indicated screening, screening pregnancies conceived by in vitro fertilization (IVF), and universal screening. Ultrasound-indicated screening was defined as performing a transvaginal ultrasound at the time of routine anatomy ultrasound in response to one of the following sonographic findings associated with an increased risk of vasa previa: low-lying placenta, marginal or velamentous cord insertion, or bilobed or succenturiate lobed placenta. The primary outcome was cost per quality adjusted life years (QALY) in U.S. dollars. The analysis was from a healthcare system perspective with a willingness to pay (WTP) threshold of $100,000 per QALY selected. One-way and multivariate sensitivity analyses (Monte-Carlo simulation) were performed. This decision-analytic model demonstrated that screening pregnancies conceived by IVF was the most cost-effective strategy with an incremental cost effectiveness ratio (ICER) of $29,186.50 / QALY. Ultrasound-indicated screening was the second most cost-effective with an ICER of $56,096.77 / QALY. These data were robust to all one-way and multivariate sensitivity analyses performed. Within our baseline assumptions, transvaginal ultrasound screening for vasa previa appears to be most cost-effective when performed among IVF pregnancies. However, both IVF and ultrasound-indicated screening strategies fall within contemporary willingness-to-pay thresholds, suggesting that both strategies may be appropriate to apply in clinical practice. This article is protected by copyright. All rights reserved. This

  9. A Case Report and Literature Review of Midtrimester Termination of Pregnancy Complicated by Placenta Previa and Placenta Accreta

    OpenAIRE

    Matsuzaki, Satoko; Matsuzaki, Shinya; Ueda, Yutaka; Tanaka, Yusuke; Kakuda, Mamoru; Kanagawa, Takeshi; Kimura, Tadashi

    2014-01-01

    Objective - Concurrent placenta previa and placenta accreta increase the risk of massive obstetric hemorrhage. Despite extensive research on the management of placenta previa (including placenta accreta, increta, and percreta), the number and quality of previous studies are limited. We present a case of placenta accreta requiring an induced second-trimester abortion because of premature rupture of the membranes (PROM). Study Design - Case report and review of the literature. Results -...

  10. Symbol "&" suture to control atonic postpartum hemorrhage with placenta previa accreta.

    Science.gov (United States)

    Li, Guang Tai; Li, Xiao Fan; Liu, Ya Jing; Li, Wei; Xu, Hong Mei

    2015-02-01

    To evaluate the efficacy and safety of a symbol "&" compression suture technique in controlling severe atonic postpartum hemorrhage with placenta previa accreta during cesarean delivery. Nine women with heavy postpartum bleeding from uterine inertia and placenta previa percret, which did not react to conventional initial management protocols, were underwent the suture in the shape of symbol "&" in China Meitan General Hospital. The suture procedure was to staple the anterior and posterior walls (of the lower uterine segment as well as corpus uterus) together using number 1 chromic catgut, with a cross at about 2 cm above the upper boundary of lower uterine segment. Symbol "&" compression suture was capable of stanching the postpartum hemorrhage immediately in all nine women. None of these patients developed complications related to this method. Subsequent pregnancies after the suture were occurred in two women and delivered with repeat cesarean section. Symbol "&" compression suture is a simple, safe and highly effective technique to control the treatment-resistant uterine atonic bleeding, particularly in previous cesarean scar at lower segment and placenta previa accreta.

  11. Nursing care for patients with placenta previa undergoing interventional therapy in the second trimester of pregnancy

    International Nuclear Information System (INIS)

    Pan Suzhao; Lu Aijin; Wang Xuezhen

    2009-01-01

    Objective: To discuss the nursing care for patients with placenta previa,who receive uterine arterial catheterization and embolization in the second trimester of pregnancy. Methods: By using superselective catheterization with Seldinger technique, bilateral uterine artery angiography and embolization were performed in 16 patients with placenta previa in the second trimester of pregnancy. Two to four hours after the procedure, rivanol intra-amniotic injection was employed to induce the abortion. Close perioperative observation and careful nursing were carried out. Results: The fetus with its subsidiary tissue was delivered in a mean time of 4.5 hours after the operation in 15 cases. No postpartum hemorrhage occurred. Induced abortion failed in one case with 26 weeks pregnancy because of a scar uterus and cervical dystocia. Hysterotomy was performed 6 days later, blood loss during the operation was about 100 ml. No nursing care related complications occurred in all 16 patients. Conclusion: Uterine arterial embolization is very helpful in making the induced abortion for the treatment of bleeding placenta previa in the second trimester of pregnancy. Strengthening of perioperative care can improve successful rate of interventional therapy and prevent the occurrence of complication. (authors)

  12. Taratura di un 'apparecchiatura per misura di piccole percentuali di uranio in soluzione acida di acqua distillata

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    d. Diana

    1965-06-01

    Full Text Available Si descrive una tecnica elio permette di misurare ilnumero di atomi di Uranio di una soluzione, con un errore non superioreal 10%.Il sistema consiste in un tubo di Geiger (Philips 18503 sistemato inun contenitore di vetro nel quale viene diluita una certa quantità di peso dinitrato di Uranile, misurato con una precisione migliore dell'1%. Al variaredella diluizione si registra il numero di particelle che il Geiger conta, e quindisi riporta in grafico. Da questi per diverse quantità di sale sciolto si determinala retta di taratura.

  13. Action of uranium on pre implanted mouse embryos; Accion del uranio sobre los embriones de preimplantacion de raton

    Energy Technology Data Exchange (ETDEWEB)

    Kundt, Miriam S [Comision Nacional de Energia Atomica, General San Martin (Argentina). Dept. de Radiobiologia

    2001-07-01

    de preimplantacion cultivados in vitro son empleados desde hace algun tiempo para evaluar los efectos de contaminantes ambientales, en especial metales. En este trabajo se ha utilizado este modelo para presentar los efectos citotoxicos, embriotoxicos y genotoxicos del uranio. Los embriones fueron obtenidos mediante superovulacion de hembras hibridas CBA x C57 Bl, apareadas luego con machos NIH y cultivados en medio M16 como medio control. Tres experimentos diferentes se llevaron adelante 'A', 'B' y 'C' utilizando nitrato de uranilo hexahidratado UO{sub 2}(NO{sub 3}){sub 2} 6H{sub 2}O como fuente de uranio. En el experimento 'A' los embriones desde el estadio de una celula se cultivaron durante 120 hs. en la misma placa, conteniendo una concentracion final de uranio de 13, 26, 52, 104 y 208 {mu}gU/ml. En el experimento 'B' los embriones fueron puestos a cultivar desde el estadio de una celula a una concentracion final de uranio de 26, 52 y 104 {mu}gU/ml, a las 24 hs. de cultivo los embriones que pasaron a 2 celulas fueron cambiados a una placa preparada nuevamente, manteniendo las mismas concentraciones de uranio que la anterior, hasta finalizar el periodo de incubacion de 120 hs. En el experimento 'C' los embriones fueron puestos a cultivar desde el estadio de una celula a una concentracion final de uranio de 26, 52 y 104 {mu}gU/ml y fueron cambiados de placa de cultivo cada 24 hs., manteniendo estas placas nuevas las mismas concentraciones de uranio que la primera y el cultivo finalizo a las 72 hs. El clivaje embrionario desde 1 celula a 2 celulas no se ha visto estadisticamente afectado respecto del control, en los 4388 embriones analizados, en los diferentes tratamientos y las diferentes concentraciones de uranio empleadas. Desde el clivaje de 2 celulas en adelante, momento que el embrion comienza a sintetizar su propio ARNm, el retraso en el desarrollo embrionario, el grado de fragmentacion, el porcentaje de embriones atresicos y las malformaciones embrionarias

  14. Topical application of recombinant activated factor VII during cesarean delivery for placenta previa.

    Science.gov (United States)

    Schjoldager, Birgit T B G; Mikkelsen, Emmeli; Lykke, Malene R; Præst, Jørgen; Hvas, Anne-Mette; Heslet, Lars; Secher, Niels J; Salvig, Jannie D; Uldbjerg, Niels

    2017-06-01

    During cesarean delivery in patients with placenta previa, hemorrhaging after removal of the placenta is often challenging. In this condition, the extraordinarily high concentration of tissue factor at the placenta site may constitute a principle of treatment as it activates coagulation very effectively. The presumption, however, is that tissue factor is bound to activated factor VII. We hypothesized that topical application of recombinant activated factor VII at the placenta site reduces bleeding without affecting intravascular coagulation. We included 5 cases with planned cesarean delivery for placenta previa. After removal of the placenta, the surgeon applied a swab soaked in recombinant activated factor VII containing saline (1 mg in 246 mL) to the placenta site for 2 minutes; this treatment was repeated once if the bleeding did not decrease sufficiently. We documented the treatment on video recordings and measured blood loss. Furthermore, we determined hemoglobin concentration, platelet count, international normalized ratio, activated partial thrombin time, fibrinogen (functional), factor VII:clot, and thrombin generation in peripheral blood prior to and 15 minutes after removal of the placenta. We also tested these blood coagulation variables in 5 women with cesarean delivery planned for other reasons. Mann-Whitney test was used for unpaired data. In all 5 cases, the uterotomy was closed under practically dry conditions and the median blood loss was 490 (range 300-800) mL. There were no adverse effects of recombinant activated factor VII and we did not measure factor VII to enter the circulation. Neither did we observe changes in thrombin generation, fibrinogen, activated partial thrombin time, international normalized ratio, and platelet count in the peripheral circulation (all P values >.20). This study indicates that in patients with placenta previa, topical recombinant activated factor VII may diminish bleeding from the placenta site without initiation

  15. A Case Report and Literature Review of Midtrimester Termination of Pregnancy Complicated by Placenta Previa and Placenta Accreta

    Directory of Open Access Journals (Sweden)

    Satoko Matsuzaki

    2015-04-01

    Full Text Available Objective - Concurrent placenta previa and placenta accreta increase the risk of massive obstetric hemorrhage. Despite extensive research on the management of placenta previa (including placenta accreta, increta, and percreta, the number and quality of previous studies are limited. We present a case of placenta accreta requiring an induced second-trimester abortion because of premature rupture of the membranes (PROM. Study Design - Case report and review of the literature. Results - A 41-year-old female presented at 20 weeks of gestation with placenta previa and PROM. Ultrasonography revealed placenta accreta with multiple placental lacunae. She then developed massive hemorrhaging just prior to a planned termination of pregnancy. We performed a hysterectomy with the intent of preserving life because of the failure of the placenta to detach and blood loss totaling 4,500 mL. Conclusion - Previous studies suggest that second-trimester pregnancy terminations in cases of placenta previa which are not complicated with placenta accreta do not have a particularly high risk of hemorrhage. However, together with our case, the literature suggests that placenta previa complicated with placenta accreta presents a significant risk of hemorrhage both during delivery and intraoperatively. Further reports are needed to evaluate the most appropriate treatment options.

  16. A Case Report and Literature Review of Midtrimester Termination of Pregnancy Complicated by Placenta Previa and Placenta Accreta.

    Science.gov (United States)

    Matsuzaki, Satoko; Matsuzaki, Shinya; Ueda, Yutaka; Tanaka, Yusuke; Kakuda, Mamoru; Kanagawa, Takeshi; Kimura, Tadashi

    2015-04-01

    Objective Concurrent placenta previa and placenta accreta increase the risk of massive obstetric hemorrhage. Despite extensive research on the management of placenta previa (including placenta accreta, increta, and percreta), the number and quality of previous studies are limited. We present a case of placenta accreta requiring an induced second-trimester abortion because of premature rupture of the membranes (PROM). Study Design Case report and review of the literature. Results A 41-year-old female presented at 20 weeks of gestation with placenta previa and PROM. Ultrasonography revealed placenta accreta with multiple placental lacunae. She then developed massive hemorrhaging just prior to a planned termination of pregnancy. We performed a hysterectomy with the intent of preserving life because of the failure of the placenta to detach and blood loss totaling 4,500 mL. Conclusion Previous studies suggest that second-trimester pregnancy terminations in cases of placenta previa which are not complicated with placenta accreta do not have a particularly high risk of hemorrhage. However, together with our case, the literature suggests that placenta previa complicated with placenta accreta presents a significant risk of hemorrhage both during delivery and intraoperatively. Further reports are needed to evaluate the most appropriate treatment options.

  17. Spectrophotometric determination of uranium with arsenazo previous liquid-liquid extraction and colour development in organic medium; Determinacion espectrofotometrica de uranio con arsenazo, previa extraccion y desarrollo del color en medio organico

    Energy Technology Data Exchange (ETDEWEB)

    Palomares Delgado, F; Vera Palomino, J; Petrement Eguiluz, J C

    1964-07-01

    The determination of uranium with arsenazo is hindered by a great number of cation which form stable complexes with the reactive and may given rise to serious interferences. By studying the optimum conditions of uranium the extraction be means of tributylphosphate solutions dissolved in methylisobuthylketone, under conditions for previous masking of the interfering cations, an organic extract was obtained containing all the uranium together with small amounts of iron. The possible interference derived from the latter element is avoided by reduction with hydroxylammoniumchlorid followed by complex formation of the Fe(II)-ortophenantroline compound in alcoholic medium. (Author) 17 refs.

  18. Placenta previa

    Science.gov (United States)

    ... cervix is the opening to the birth canal. Causes During pregnancy, the placenta moves as the womb stretches and ... care provider can diagnose this condition with a pregnancy ultrasound. ... or part of the cervix, a vaginal delivery can cause severe bleeding. This can be deadly to both ...

  19. A novel scoring system for predicting adherent placenta in women with placenta previa.

    Science.gov (United States)

    Tanimura, Kenji; Morizane, Mayumi; Deguchi, Masashi; Ebina, Yasuhiko; Tanaka, Utaru; Ueno, Yoshiko; Kitajima, Kazuhiro; Maeda, Tetsuo; Sugimura, Kazuro; Yamada, Hideto

    2018-04-01

    Placenta previa (PP) is one of the most significant risk factors for adherent placenta (AP). The aim of this study was to evaluate the diagnostic efficacy of a novel scoring system for predicting AP in pregnant women with PP. This prospective cohort study enrolled 175 women with PP. The placenta previa with adherent placenta score (PPAP score) is composed of 2 categories: (1) past history of cesarean section (CS), surgical abortion, and/or uterine surgery; and (2) ultrasonography and magnetic resonance imaging findings. Each category is graded as 0, 1, 2, or 4 points, yielding a total score between 0 and 24. When women with PP had PPAP score ≥8, they were considered to be at a high risk for AP and received placement of preoperative internal iliac artery occlusion balloon catheters. If they were found to have AP during CS, they underwent hysterectomy or placenta removal using advanced bipolar with balloon catheter occlusion. The predictive accuracy of PPAP score was evaluated. In total, 23 of the 175 women with PP were diagnosed as having AP, histopathologically or clinically. Twenty-one of 24 women with PPAP score ≥8 had AP, whereas two of 151 women with PPAP score PPAP scoring system may be useful for predicting AP in women with PP. Copyright © 2018 Elsevier Ltd. All rights reserved.

  20. Safe spinal anesthesia in a woman with chronic renal failure and placenta previa

    Directory of Open Access Journals (Sweden)

    Beyazit Zencirci

    2010-05-01

    Full Text Available Beyazit ZencirciKahramanmaras, TurkeyBackground: Chronic renal failure is strongly associated with poor pregnancy outcome. Women dependent on hemodialysis before conception rarely achieve a successful live birth.Case presentation: A 31-year-old multiparous Turkish woman was scheduled for cesarean section under spinal anesthesia at 37 weeks and five days’ gestation because of hemorrhage due to secondary placenta previa. Spinal anesthesia with 8 mg of hyperbaric bupivacaine was successfully performed. Invasive blood pressure, central venous pressure, and heart rate were stable during the surgery. The mother returned to regular hemodialysis on the first postoperative day.Conclusion: Pregnancy is uncommon in women with chronic renal failure requiring chronic dialysis. Rates of maternal hypertension, pre-eclampsia, anemia, and infection in the pregnant chronic dialysis patient are high. However, our findings suggest that with careful, close, and effective monitoring preoperatively and intraoperatively, spinal anesthesia can be safely performed for cesarean section in patients undergoing hemodialysis.Keywords: chronic renal failure, pregnancy, spinal anesthesia, hemodialysis, placenta previa

  1. Perinatal outcome and near-miss morbidity between placenta previa versus abruptio placentae

    International Nuclear Information System (INIS)

    Siddique, S.A.; Tariq, G.; Sheikh, A.; Hussain, F.S.U.; Memon, K.A.

    2010-01-01

    To compare perinatal outcome and near-miss morbidities between placenta previa versus abruptio placentae in patients of antepartum haemorrhage (APH). Patients with APH diagnosed as placenta previa and abruptio placentae who delivered after 24 weeks of regnancy were selected from labour room. Outcome measures were birth weight, neonatal intensive care admission, stillbirth, perinatal mortality rates, near-miss, surgical intensive care admission, postpartum haemorrhage, hysterectomy, massive transfusion, renal failure, coagulopathy and maternal death. Stillbirth was defined as a fetus weighing greater or equal to 500 gm showing no sign of life after birth. Near-miss was defined as severe organ dysfunction which if not treated appropriately, could result in death. Descriptive statistics were calculated and chi-square was applied with significance level < 0.05. Stillbirths and perinatal mortality rates were significantly higher in abruptio placentae, 52.97% versus 18.18% and 534/1000 versus 230/1000 (p < 0.01). Near-miss cases were also significantly higher in abruptio placentae, 22.27%. Verus 11.18% (p < 0.01). Hypovolemic shock and coagulation failure were also significantly higher in abruptio placentae (p < 0.05). (author)

  2. Frequency, Risk Factors, and Adverse Fetomaternal Outcomes of Placenta Previa in Northern Tanzania

    Directory of Open Access Journals (Sweden)

    Elizabeth Eliet Senkoro

    2017-01-01

    Full Text Available Background and Objective. Placenta previa (PP is a potential risk factor for obstetric hemorrhage, which is a major cause of fetomaternal morbidity and mortality in developing countries. This study aimed to determine frequency, risk factors, and adverse fetomaternal outcomes of placenta previa in Northern Tanzania. Methodology. A retrospective cohort study was conducted using maternally-linked data from Kilimanjaro Christian Medical Centre birth registry spanning 2000 to 2015. All women who gave birth to singleton infants were studied. Adjusted odds ratios (ORs with 95% confidence intervals for risk factors and adverse fetomaternal outcomes associated with PP were estimated in multivariable logistic regression models. Result. A total of 47,686 singleton deliveries were analyzed. Of these, the frequency of PP was 0.6%. Notable significant risk factors for PP included gynecological diseases, alcohol consumption during pregnancy, malpresentation, and gravidity ≥5. Adverse maternal outcomes were postpartum haemorrhage, antepartum haemorrhage, and Caesarean delivery. PP increased odds of fetal Malpresentation and early neonatal death. Conclusion. The prevalence of PP was comparable to that found in past research. Multiple independent risk factors were identified. PP was found to have associations with several adverse fetomaternal outcomes. Early identification of women at risk of PP may help clinicians prevent such complications.

  3. Placenta Previa Percreta: A Case Report of Successful Management via Conservative Surgery

    Directory of Open Access Journals (Sweden)

    Silvia Canonico

    2013-01-01

    Full Text Available Placenta percreta is one of the most serious complications of placenta previa and is frequently associated with severe obstetric hemorrhage usually necessitating hysterectomy. We present a case of placenta previa percreta diagnosed by ultrasound and magnetic resonance imaging techniques, in which we accomplished conservative management of postpartum hemorrhage. The management we propose includes the following steps: preventive catheterization of the descending aorta via transhumeral access; Stark cesarean delivery; uterotonics drugs; Affronti endouterine square hemostatic sutures; intrauterine application of Bakri balloon and partial filling with 100 mL of normal saline; B Lynch suture, hysterorrhaphy, and filling a Bakri balloon with up to 500 mL of normal saline; reversible radiological embolization; and/or surgical ligation of the uterine arteries. The bleeding stopped following placement of Affronti sutures combined with external (B-Lynch suture and internal (Bakri balloon uterine compression. Our experience indicates that this conservative method can be considered an option in the management of selected cases of pregnancy at high risk for intrapartum hemorrhage.

  4. Impact of targeted scanning protocols on perinatal outcomes in pregnancies at risk of placenta accreta spectrum or vasa previa.

    Science.gov (United States)

    Melcer, Yaakov; Jauniaux, Eric; Maymon, Shlomit; Tsviban, Anna; Pekar-Zlotin, Marina; Betser, Moshe; Maymon, Ron

    2018-04-01

    Placenta accreta spectrum and vasa previa (VP) are congenital disorders of placentation associated with high morbidity and mortality for both mothers and newborns when undiagnosed before delivery. Prenatal diagnosis of these conditions is essential to allow multidisciplinary management and thus improve perinatal outcomes. The objective of the study was to compare perinatal outcome in women with placenta accreta spectrum or vasa previa before and after implementation of targeted scanning protocols. This retrospective study included 2 nonconcurrent cohorts for each condition before and after implementation of the corresponding protocols (2004-1012 vs 2013-2016 for placenta accreta spectrum and 1988-2007 vs 2008-2016 for vasa previa). Clinical reports of women diagnosed with placenta accreta spectrum and vasa previa during the study periods were reviewed and outcomes were compared. In total, there were 97 cases of placenta accreta spectrum and 51 cases with vasa previa, all confirmed at delivery. In both cohorts, the prenatal detection rate increased after implementation of the scanning protocols (28 of 65 cases [43.1%] vs 31 of 32 cases [96.9%], P accreta spectrum and 9 of 18 cases [50%] vs 29 of 33 cases [87.9%], 87.9%, P accreta spectrum cohort, the estimated blood loss and the postoperative hospitalization stay decreased between periods (1520 ± 845 vs 1168 ± 707 mL, P accreta spectrum and vasa previa was associated with improved maternal and neonatal outcomes. The continuous increases in the rates of caesarean deliveries and use of assisted reproductive technology highlights the need to develop training programs and introduce targeted scanning protocols at the national and international levels. Copyright © 2018 Elsevier Inc. All rights reserved.

  5. Reliability of trans-abdominal ultrasonography in determining exact location of placenta in patients of placenta previa major

    International Nuclear Information System (INIS)

    Zafar, M.; Hayat, N; Gul, U.

    2017-01-01

    Objective: To determine the reliability of trans-abdominal ultrasonographical localization of placenta in cases of placenta previa major, by taking peroperative finding as gold standard. Study Design: Validation study. Place and Duration of Study: Maternity ward, Obstetrics and Gynecology department, Military Hospital Rawalpindi from 2007 to 2008. Patients and Methods: A total of 100 patients fulfilling the inclusion and exclusion criteria were recruited for the study. These patients were admitted to the maternity ward, where trans-abdominal ultrasound was performed, site of the placenta and its relation to the internal os was documented. These patients under went elective cesarean section, during which the site and relation of the placenta to the internal os was confirmed. Results: The mean age of patients was 34.23 +- 6.76 years. Transabdominal ultrasound had a sensitivity of 93.4 percent in localizing major placenta previa while the specificity was 83 percent. Positive predictive value was 94.7 percent, negative predictive value was 80 percent and accuracy 91 percent. Conclusion: Trans-abdominal ultrasound was found highly effective in diagnosing and localizing placenta previa. (author)

  6. ACCRETA COMPLICATING COMPLETE PLACENTA PREVIA IS CHARACTERIZED BY REDUCED SYSTEMIC LEVELS OF VASCULAR ENDOTHELIAL GROWTH FACTOR AND EPITHELIAL-TO-MESENCHYMAL TRANSITION OF THE INVASIVE TROPHOBLAST

    Science.gov (United States)

    Wehrum, Mark J.; Buhimschi, Irina A.; Salafia, Carolyn; Thung, Stephen; Bahtiyar, Mert O.; Werner, Erica F.; Campbell, Katherine H.; Laky, Christine; Sfakianaki, Anna K.; Zhao, Guomao; Funai, Edmund F.; Buhimschi, Catalin S.

    2011-01-01

    OBJECTIVE To characterize serum angiogenic factor profile of women with complete placenta previa and determine if invasive trophoblast differentiation characteristic of accreta, increta or percreta shares features of epitehelial-mesenchymal-transition (EMT). STUDY DESIGN We analyzed gestational age matched serum samples from 90 pregnant women with either complete placenta previa (n=45) or uncomplicated pregnancies (n=45). Vascular-endothelial-growth-factor (VEGF), placental-growth-factor (PlGF) and soluble fms-like-tyrosine-kinase-1 (sFlt-1) were immunoassayed. VEGF and phosphotyrosine (P-Tyr) immunoreactivity was surveyed in histological specimens relative to expression of vimentin and cytokeratin-7. RESULTS Women with previa and invasive placentation [accreta (n=5); increta (n=6); percreta (n=2)] had lower systemic VEGF (invasive previa: median [IQR]: 0.8[0.02–3.4] vs. control: 6.5[2.7–10.5] pg/mL, P=0.02). VEGF and P-Tyr immunostaining predominated in the invasive extravillous trophoblasts (EVT) which co-expressed vimentin and cytokeratin-7, a EMT feature and tumor-like cell phenotype. CONCLUSIONS Lower systemic free VEGF and a switch of the interstitial EVT to a metastable cell phenotype characterize placenta previa with excessive myometrial invasion. PMID:21316642

  7. Expectativas previas y satisfacción del usuario en un programa de tratamiento de mantenimiento con metadona

    OpenAIRE

    Forcada Chapa, Rafael; Santos Díez, F. J.; González Monte, Carmen

    2006-01-01

    Los indicadores de satisfacción miden el grado de conformidad con la atención recibida y se construyen en base a las apreciaciones subjetivas de los pacientes. Los factores que influyen en la percepción de los tratamientos con metadona son: la utilización del fármaco, las listas de espera y la influencia sobre aspectos laborales. Se plantea este estudio con los objetivos de conocer las expectativas de los pacientes, previas al inicio de un programa de tratamiento con metadona y estudiar el gr...

  8. CATEGORIZACIÓN DE LAS IDEAS PREVIAS DE LOS ESTUDIANTES DE GRADO SÉPTIMO SOBRE EL CONCEPTO DE RESPIRACIÓN ANIMAL

    Directory of Open Access Journals (Sweden)

    Bayron Gil Bohórquez

    2015-12-01

    Full Text Available La escuela es un escenario de transición desde las ideas previas de los estudiantes hacia formas de comprensión más cercanas a las del conocimiento científico, por ello las ideas previas constituyen el punto de partida más importante en el diseño y la implementación de toda Unidad Didáctica basada en el enfoque de aprendizaje significativo. Se analizaron las ideas previas de 40 estudiantes del grado séptimo (11-15 años de la Institución Educativa Departamental San Gabriel, ubicado en el municipio de Cajicá, Cundinamarca; a través de la aplicación de un instrumento fundamentado en una pregunta abierta ¿Cómo respiramos?, la creación de un mapa conceptual acerca de la respiración en los animales, y un cuestionario con preguntas de selección múltiple y de tipo Falso o Verdadero que permiten conocer lo que el estudiante sabe acerca del concepto de respiración animal. Por último, se realiza la sistematización de datos para un posterior análisis cualitativo de las ideas previas utilizando el programa NVivo 10. Las ideas previas de los estudiantes acerca del concepto de Respiración Animal se asocian principalmente al proceso de intercambio gaseoso. Se observan dificultades para explicar procesos a nivel celular y de tipo estructura-función; aunque los estudiantes evidencian la importancia de la respiración para los animales y su relación con el sistema circulatorio. Es posible categorizar las ideas previas en los modelos explicativos: Intercambio gaseoso, vitalismo, pseudomolecular, y órganos-estructuras.

  9. Placenta Prévia: Fatores de risco para o Acretismo Placenta Previa: Risk Factors for Accretion

    Directory of Open Access Journals (Sweden)

    Maria Regina Torloni

    2001-08-01

    Full Text Available Objetivo: investigação dos fatores de risco associados ao acretismo em pacientes com placenta prévia (PP. Métodos: foi realizada uma análise retrospectiva caso-controle de todos os prontuários de pacientes com diagnóstico de PP que tiveram seus partos na Maternidade Escola Vila Nova Cachoeirinha (São Paulo entre 1986 e 1998. O grupo com acretismo foi comparado ao grupo sem acretismo quanto à idade, paridade, antecedentes de abortamentos, curetagens e cesarianas, o tipo de PP e a área predominante de inserção placentária. Para avaliar a associação entre a variável dependente (acretismo placentário e as variáveis independentes (características maternas e placentária foram utilizados o teste do chi², análise univariada e multivariada, considerando-se significantes os valores de p Purpose: to investigate risk factors associated with accretion in placenta previa (PP patients. Methods: this was a retrospective case-control study of all the records of patients who delivered between 1986-1998 at Maternidade Escola de Vila Nova Cachoeirinha (São Paulo with a diagnosis of placenta previa. The groups with and without accretion were compared regarding age, parity, previous history of miscarriage, curettage and cesarean section, type of PP and predominant area of placental attachment. Possible associations between the dependent (accretion and independent (maternal and placental characteristics variables were evaluated using the chi² test, univariate and multivariate analyses. Results: reviewing 245 cases of PP, two risk factors were significantly associated with accretion: central placenta previa (odds ratio (OR: 2.93 and two or more previous cesarean sections(OR: 2.54. Based on these data, a predictive model was constructed, according to which a patient with central PP and two more previous cesarean sections has a 44.4% risk for accretion. Conclusions: results of the current study may help obstetricians in the classification of their

  10. Complejos de halógeno acetatos de uranio (IV y torio (IV con sulfoxidos y fosfinoxidos

    Directory of Open Access Journals (Sweden)

    Omar Velasquez

    2010-09-01

    Full Text Available En este trabajo se ha Investigado el efecto sterico sobre los modos de coordinación del grupo carboxilato (unidentado, bidentado y puente, en complejos de halógeno acetato con fosfinóxidos y sulfóxidos y la correlación de los resultadoscon el modelo "Cone Angle" e\\ cual ha sido descrito en otra publicación previa' Los complejos preparados son: M(RCO ^ .nL donde n = 4, M = Th ó U, L = Me^SO (dmso, R = CF,3 y L = Me3P0 (tmpo; n = 3, M = Th, L = tmpo, R = CF3 y L = ppo o dmso, R OCCI3; M = U, L = t p p o , R =CF3 y L =dmso, dpso, R = C C l 3 ; n = 2 , M = T h , L = tppo, R = CF3, CHCI^On^ 1, M = Th ó U, L =dmso.

  11. Maintenance nifedipine therapy for preterm symptomatic placenta previa: A randomized, multicenter, double-blind, placebo-controlled trial.

    Directory of Open Access Journals (Sweden)

    Eric Verspyck

    Full Text Available To assess the impact of maintenance nifedipine therapy on pregnancy duration in women with preterm placenta previa bleeding.PPADAL was a randomized, double-blind, placebo-controlled trial conducted between 05/2008 and 05/2012 in five French hospitals. The trial included 109 women, aged ≥ 18 years, with at least one episode of placenta previa bleeding, intact membranes and no other pregnancy complication, at gestational age 24 to 34 weeks and after 48 hours of complete acute tocolysis. Women were randomly allocated to receive either 20 mg of slow-release nifedipine three times daily (n = 54 or placebo (n = 55 until 36 + 6 weeks of gestation. The primary outcome for the trial was length of pregnancy measured in days after enrolment. Main secondary outcomes were rates of recurrent bleeding, cesarean delivery due to hemorrhage, blood transfusion, maternal side effects, gestational age at delivery and adverse perinatal outcomes (perinatal death, chronic lung disease, neonatal sepsis, intraventricular hemorrhage > grade 2, perventricular leukomalacia > grade 1, or necrotizing enterocolitis. Analysis was by intention to treat.Mean (SD prolongation of pregnancy was not different between the nifedipine (n = 54 and the placebo (n = 55 group; 42.5 days ± 23.8 versus 44.2 days ± 24.5, p = 0.70. Cesarean due to hemorrhage performed before 37 weeks occurred more frequently in the nifedipine group in comparison with the placebo group (RR, 1.66; 95% confidence interval, 1.05-2.72. Adverse perinatal outcomes were comparable between groups; 3.8% for nifedipine versus 5.5% for placebo (relative risk, 0.52; 95% confidence interval 0.10-2.61. No maternal mortality or perinatal death occurred.Maintenance oral nifedipine neither prolongs duration of pregnancy nor improves maternal or perinatal outcomes.ClinicalTrials.gov NCT00620724.

  12. Caracteristicas de las personas que acuden a las consultas de demanda del centro de salud sin citación previa

    Directory of Open Access Journals (Sweden)

    Pomar Carlos Isanta

    2000-01-01

    Full Text Available FUNDAMENTO: El tiempo de espera para acceder a la consulta está considerado un indicador de satisfacción. Las visitas no urgentes, realizadas sin cita previa, provocan un incremento del tiempo de espera de los pacientes citados, con la consiguiente insatisfacción de los mismos. El objetivo del estudio persigue la valoración cuantitativa de este tipo de visitas y conocer las características de las mismas, para introducir las medidas destinadas a su corrección y racionalización. MÉTODOS: Estudio descriptivo. Se realizó un registro que recogiera las características de los pacientes que originan las consultas sin cita previa, como la edad y el sexo y las relativas a la consulta: motivo, modalidad, jornada laboral y si era realizada de forma directa o indirecta. RESULTADOS: El 14,19% de consultas a demanda no urgentes son sin citación previa. Con el análisis factorial de correspondencias múltiple se identifican dos perfiles de consultas: las directas, solicitadas por pacientes jóvenes, por enfermedad o tareas burocráticas, al final de la consulta de la mañana, estando ellos presentes, y las consultas indirectas, ocasionadas durante las consultas con cita previa por pacientes que solicitan recetas. CONCLUSIONES: Hay un elevado número de visitas sin cita previa. Son precisas medidas que puedan conducir a la utilización del sistema de organización de las consultas y a la mejora de aquellas situaciones que impliquen una falta de accesibilidad, con la finalidad última de mejorar la satisfacción de los usuarios de los servicios sanitarios públicos.

  13. Prenatal ultrasound diagnosis and outcome of placenta previa accreta after cesarean delivery: a systematic review and meta-analysis.

    Science.gov (United States)

    Jauniaux, Eric; Bhide, Amar

    2017-07-01

    Women with a history of previous cesarean delivery, presenting with a placenta previa, have become the largest group with the highest risk for placenta previa accreta. The objective of the study was to evaluate the accuracy of ultrasound imaging in the prenatal diagnosis of placenta accreta and the impact of the depth of villous invasion on management in women presenting with placenta previa or low-lying placenta and with 1 or more prior cesarean deliveries. We searched PubMed, Google Scholar, clinicalTrials.gov, and MEDLINE for studies published between 1982 and November 2016. Criteria for the study were cohort studies that provided data on previous mode of delivery, placenta previa, or low-lying placenta on prenatal ultrasound imaging and pregnancy outcome. The initial search identified 171 records, of which 5 retrospective and 9 prospective cohort studies were eligible for inclusion in the quantitative analysis. The studies were scored on methodological quality using the Quality Assessment of Diagnostic Accuracy Studies tool. The 14 cohort studies included 3889 pregnancies presenting with placenta previa or low-lying placenta and 1 or more prior cesarean deliveries screened for placenta accreta. There were 328 cases of placenta previa accreta (8.4%), of which 298 (90.9%) were diagnosed prenatally by ultrasound. The incidence of placenta previa accreta was 4.1% in women with 1 prior cesarean and 13.3% in women with ≥2 previous cesarean deliveries. The pooled performance of ultrasound for the antenatal detection of placenta previa accreta was higher in prospective than retrospective studies, with a diagnostic odds ratios of 228.5 (95% confidence interval, 67.2-776.9) and 80.8 (95% confidence interval, 13.0-501.4), respectively. Only 2 studies provided detailed data on the relationship between the depth of villous invasion and the number of previous cesarean deliveries, independently of the depth of the villous invasion. A cesarean hysterectomy was performed in

  14. Comparación del nivel de condiciones previas de rendimiento de tenistas de élite (estudio de caso

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    Jiří Zháněl

    2015-04-01

    Full Text Available En el mundo del tenis de hoy en día, hay una clara tendencia hacia un juego físicamente exigente, en el que las condiciones previas motrices más importantes son la velocidad (acción y reacción, la fuerza (sobre todo la inicial y la explosiva, la fuerza resistencia y las habilidades específicas de coordinación. El presente estudio se basa en la teoría retrospectiva. El objetivo de la investigación fue el análisis longitudinal del nivel de condiciones previas somáticas y motrices de tenistas checos de élite (el tenista Tomas Berdych –TB– y la tenista Petra Kvitova –PK–. Con fecha 1 de junio de 2014, Tomas Berdych es el tenista número 1 de República Checa y el número 6 del mundo en el Ranking ATP (4330 puntos, habiendo logrado su mejor ranking hasta la fecha en 2013 (número 5 del mundo; con la misma fecha la tenista Petra Kvitova también es la tenista número 1 de República Checa y la número 6 del mundo en el Ranking WTA (4600 puntos, habiendo logrado su mejor ranking hasta la fecha en 2011 (número 2 del mundo. Los dos tenistas fueron evaluados longitudinalmente mediante la batería de test TENDIAG1, la cual contiene tres ítems somáticos y seis ítems motores. Los resultados de ambos tenistas claramente mostraron que, a lo largo de todo el periodo de monitorización, su puntuación total en la batería de test se encontraba por encima de la media de la población de tenistas. La evaluación de las diferencias entre sexos mostró un nivel significativamente más alto en la mayoría de ítems en el tenista TB, excepto en los ítems de flexibilidad del torso y de velocidad de reacción de brazos y piernas. La tenista PK obtuvo un mejor nivel en el índice de movilidad del hombro. Los resultados proporcionan interesantes conocimientos y sugerencias para el entrenamiento del tenis.

  15. Las mineralizaciones de uranio en las rocas volcánicas de Macusani. Puno (Perú

    Directory of Open Access Journals (Sweden)

    Arribas, A.

    1985-12-01

    minerales de U se hallan principalmente en los niveles superiores de la pila volcánica.
    2. Las rocas encajantes corresponden a ignimbritas riolíticas y riodacíticas, pliocuaternarlas, formadas por cuarzo, sanidina, oligoclasa, biotita y, ocasionalmente, moscovita y andalucita, en una matriz vítrea, parcialmente desvitrificada, que contiene numerosos c1astos de lutitas.
    3. La biotita, cuarzo ahumado y andalucita son muy abundantes en los niveles mineralizados. 4. Los minerales metálicos se componen casi exclusivamente de pechblenda masiva, más o menos transformada en gummitas, fosfatos y silicatos de U, y muy escasos sulfuros de Fe. 5. La pechblenda rellena fracturas que miden entre unos centímetros y varios metros de longitud, y de 1 a 100 milímetros de anchura. Algunas de estas fracturas son subverticales y debidas a la contracción que dio lugar a la disyunción columnar. Otras son subhorizonta1es y paralelas a un sistema de cizallas dúctiles, conjugadas, que se desarrolló por compactación y asentamiento de los materiales piroclásticos que contienen la mineralización. De acuerdo con esos factores, se propone en este trabajo un modelo metalogénico preliminar para explicar el origen de este singular tipo de yacimientos de uranio.

  16. Effect of low B-Lynch suture on menstrual cycle recovery and sex hormone levels in patients after cesarean section for placenta previa

    Directory of Open Access Journals (Sweden)

    Su-Lan Zhang

    2016-03-01

    Full Text Available Objective: To explore the effect of low B-Lynch suture on the menstrual cycle recovery and sex hormone levels in patients after cesarean section for placenta previa. Methods: A total of 40 patients who were admitted in our hospital from August, 2013 to August, 2015 for cesarean section due to placenta previa were included in the study and randomized into the observation group and the control group. The patients in the observation group were given low B-lynch suture, while in the control group, yarns were plugged in the uterus. The bleeding during operation and 24 h after operation, the postpartum lochia duration, and menstrual cycle recovery in the two groups were observed. The postpartum FSH, E2, and LH levels in the two groups were determined. Results: The amount of bleeding during operation and 24 h after operation in the observation group was significantly less than that in the control group (P0.05. The comparison of FSH, E2, and LH levels between the two groups was not statistically significant (P>0.05. Conclusions: Low B-Lynch suture can effectively reduce the amount of bleeding after cesarean section for placenta previa, and has no effect on the menstrual recovery and ovarian function with a simple operation and less postoperative complications; therefore, it deserves to be widely recommended in the clinic.

  17. Assessment of total placenta previa by magnetic resonance imaging and ultrasonography to detect placenta accreta and its variants.

    Science.gov (United States)

    Peker, Nuri; Turan, Volkan; Ergenoglu, Mete; Yeniel, Ozgur; Sever, Ahmet; Kazandi, Mert; Zekioglu, Osman

    2013-03-01

    To evaluate the importance of ultrasonography (US) and magnetic resonance imaging (MRI) in detecting placental adherence defects. Patients diagnozed with total placenta previa (n = 40) in whom hysterectomy was performed due to placental adherence defects (n = 20) or in whom the placenta detached spontaneously after a Cesarean delivery (n = 20) were included into the study between June 2008 and January 2011, at the Department of Obstetrics and Gynecology Ege University (lzmir Turkey). Gray-scale US was used to check for any placental lacunae, sub-placental sonolucent spaces or a placental mass invading the vesicouterine plane and bladder Intra-placental lacunar turbulent blood flow and an increase in vascularization in the vesicouterine plane were evaluated with color Doppler mode. Subsequently all patients had MRI and the results were compared with the histopathologic examinations. The sensitivity of MRI for diagnosis of placental adherence defects before the operation was 95%, with a specificity of 95%. In the presence of at least one diagnostic criterion, the sensitivity and specificity of US were 87.5% and 100% respectively, while the sensitivity of color Doppler US was 62.5% with a specificity of 100%. Currently MRI appears to be the gold standard for the diagnosis of placenta accreta. None of the ultrasonographic criteria is solely sufficient to diagnose placental adherence defects, however they assist in the diagnostic process.

  18. Uranium-Based Cermet Alloys; Cermets a base d'uranium; Metallokeramicheskie splavy na osnove urana; Cermets a base de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, V. E.; Zelenskij, V. F.; Voloshchuk, A. I.; Grishok, V. N. [Fiziko-Tekhnicheskij Institut an USSR, Khar' kov, SSSR (Russian Federation)

    1963-11-15

    The paper describes certain features of dispersion-hardened uranium-based cermets. As possible hardening materials, consideration was given to UO{sub 2}, UC, Al{sub 2}O{sub 3}, MgO and UBe{sub 13}. Data were obtained on the behaviour of uranium alloys containing the above-mentioned admixtures during creep tests, short-term strength tests and cyclic thermal treatment. The corrosion resistance o f UBe{sub 13}-based uranium alloys was also studied. )author) [French] Les auteurs decrivent certaines proprietes de cermets a base d'uranium, dont la resistance a ete accrue a l'aide de particules dispersees. Les materiaux utilises a cette fin sont notamment: UO{sub 2}, UC, Al{sub 2}O{sub 3}, MgO et UBe{sub 13}. Les auteurs indiquent les donnees obtenues sur le comportement des cermets a l'uranium; durant les essais de fluage, les essais de resistance a court terme et le traitement thermique cyclique, en mentionnant les substances ajoutees. Ils etudient enfin la resistance a la corrosion des cermets d'uranium et UBe{sub 13}. (author) [Spanish] Los autores describen algunas propiedades de los cermets a base de uranio, reforzados por particulas de diversos compuestos en dispersion. En calidad de posibles materiales de refuerzo, ensayaron el UO{sub 2}, el UC, el Al{sub 2}O{sub 3}, el MgO y el UBe{sub 13}. Obtuvieron datos sobre el comportamiento de esas aleaciones en ensayos de fluencia, ensayoe rapidos de resistencia y tratamiento termico ciclico. Por ultimo, estudiaron la resistencia a la corrosion de las aleaciones de uranio a base de UBe{sub 13}. (author) [Russian] Daetsya opisanie nekotorykh svojstv metallokeramicheskikh splavov urana, uprochnennykh dispersionnymi chastitsami. V kachestve vozmozhnykh uprochnyayushchikh materialov izuchalis' UO{sub 2}, UC, Al{sub 2}O{sub 3} , MgO i UBe{sub 13}. Polucheny dannye o povedenii splavov urana s ukazannymi primesyami pri kripovykh ispytaniyakh, pri kratkovremennykh prochnostnykh ispytaniyakh i pri tsiklicheskoj termoobrabotke

  19. Extensión del método de datación basado en Pb-210 al análisis de la contaminación de suelos por uranio

    OpenAIRE

    Cerezo Fernández, Agustín

    2017-01-01

    RESUMEN: Objetivo principal de este trabajo ha sido la datación de un testigo de 50 cm de profundidad de sedimentos extraído en el lago San Vicente (Argentina) en el año 2016 usando el método del 210Pb en exceso. Al analizar las medidas realizadas se detectó la posible contaminación por Uranio natural. En consecuencia se desarrolló un método para analizar cuantitativamente la presencia de dicha contaminación en los sedimentos. La datación de los sedimentos se ha realizado haciendo uso de m...

  20. Increased Levels of Cell-Free Human Placental Lactogen mRNA at 28-32 Gestational Weeks in Plasma of Pregnant Women With Placenta Previa and Invasive Placenta

    Science.gov (United States)

    Sekizawa, Akihiko; Ventura, Walter; Koide, Keiko; Hori, Kyouko; Okai, Takashi; Masashi, Yoshida; Furuya, Kenichi; Mizumoto, Yoshifumi

    2014-01-01

    We compared the levels of cell-free human placental lactogen (hPL) messenger RNA (mRNA) in maternal plasma at 28 to 32 weeks of gestation between women with diagnosis of placenta previa or invasive placenta and women with an uneventful pregnancy. Sensitivity and specificity of hPL mRNA for the prediction of invasive placenta were further explored. Plasma hPL mRNA were quantified by real-time reverse-transcriptase polymerase chain reaction in women with placenta previa (n = 13), invasive placenta (n = 5), and normal pregnancies (n = 92). Median (range) hPL mRNA was significantly higher in women with placenta previa, 782 (10-2301) copies/mL of plasma, and in those with invasive placenta, 615 (522-2102) copies/mL of plasma, when compared to normal pregnancies, 90 (4-4407) copies/mL of plasma, P < .01 and P < .05, respectively. We found a sensitivity of 100% and a specificity of 61.5% for the prediction of invasive placenta among women with placenta previa. In conclusion, expression of hPL mRNA is increased in plasma of women with placenta previa and invasive placenta at 28 to 32 weeks of gestation. PMID:23744883

  1. La relevancia de la deliberación del consumidor en el ecosistema digital previa a la decisión de compra

    OpenAIRE

    Zevallos Miranda, Fernando R.

    2014-01-01

    Este estudio analiza el rol y la importancia que ha adquirido la búsqueda de información, conversación en foros y redes sociales y deliberación previa a la toma decisiones en el proceso de compra. Partiendo de la hipótesis de que el fácil acceso de los usuarios de Internet a reseñas y prescripciones sobre productos y marcas es uno de los principales detonantes de este fenómeno, se presentan los antecedentes y las opiniones de expertos en relación a la relevancia que ha cobrado la información ...

  2. La práctica de los deportes de lucha. Un estudio preliminar sobre la experiencia previa de los estudiantes de la Licenciatura en Ciencias del Deporte

    OpenAIRE

    Villamón Herrera, Miguel; Gutiérrez García, Carlos; Espartero Casado, Julián; Molina Alventosa, J. Pere

    2005-01-01

    En este trabajo se presenta un primer estudio sobre la experiencia previa en la práctica de deportes de lucha que tienen los estudiantes de la Licenciatura en Ciencias de la Actividad Física y el Deporte. El estudio se basó en la recogida y análisis de datos procedente de un cuestionario administrado a los estudiantes de primer ciclo de dicha licenciatura, de las universidades de Valencia y León, al inicio de los cursos académicos 2001-2002 y 2002-2003. Los resultados muestran que cerca del 5...

  3. Pregnancy Complications: Placenta Previa

    Science.gov (United States)

    ... Careers Archives Health Topics Pregnancy Before or between pregnancies Nutrition, weight & fitness Prenatal care Is it safe? Labor & ... Report Cards Careers Archives Pregnancy Before or between pregnancies Nutrition, weight & fitness Prenatal care Is it safe? Labor & ...

  4. Origen, transporte y deposición del uranio en los yacimientos en pizarras de la provincia de Salamanca

    Directory of Open Access Journals (Sweden)

    Arribas, A.

    1985-12-01

    orebody is compared with similar U deposits in Spain and elsewhere, and the origin of the mineralization is attributed to seismic pumping of U contained in the CEG carbonaceous slates.
    According to this model, the strains developed in the Hercynian basement around shear zones resulting from the Alpine tectonic activity, during Lower to Middle Tertiary times, would have given rise to episodic remobilizations of the U by hydrothermal flu ids. Consequently, when the dilatant zones collapsed, these U bearing solutions, geothermal in character, were expelled towards the surface depositing the U and accompanying minerals in fractures and breccias associated to the wrench faults.

    Las numerosas mineralizaciones de uranio existentes en el complejo esquisto grauváquico (CEG de la Península Ibérica, pertenecientes a la paragénesis carbonatos, pechblenda (coifinita, adularia y sulfuros de Fe, tienen, además de una considerable importancia económica, un gran interés metalogénico, ya que su origen no ha podido ser explicado todavía de forma convincente. Así, desde 1959, estas mineralizaciones se han venido atribuyendo sucesivamente a una deposición del U en zonas fracturadas y brechificadas del basamento hercínico como consecuencia de uno de estos procesos:
    - magmáticos, por transporte del U en fluidos hidrotermales relacionados con la evolución y emplazamiento de los granitos hercínicos.
    - supergénicos, por liberación del U de los granitos durante los procesos de meteorización y erosión que dieron lugar a la penillanura pliocena.
    - de segregación, por lixiviación del U de las rocas plutónicas como consecuencia de movimientos tectónicos tardihercínicos y/o alpinos.
    - de difusión, por redistribución del U contenido en los metasedimentos fértiles del CEG por difusión térmica o flujo hidrotermal.
    En este trabajo, basándose en los estudios de campo y laboratorio llevados a cabo últimamente en min a FE, la m

  5. El sistema granito-mineralización de uranio de El Berrocal como análogo natural de un almacenamiento de residuos radiactivos

    Directory of Open Access Journals (Sweden)

    Astudillo, J.

    1993-08-01

    Full Text Available This work summarizes the analogical study of the radioactive elements and rare earths are deposits applied to the modelling and validation of the migration/retention processes of the high level radioactive artificial isotopes in a geological environment. The geological, mineralogical and geochemical characteristics of the El Berrocal granite- U mineralization system suggest that this system cannot be considered as a global natural analogue for a radioactive waste repository. However, the low-temperature hydrothermal processes, which affected it, including that one which originated the uraniferous mineralization, as well as the weathering processes, can be considered as geochemical processes analogous to those that could take place in a high level radioactive repository.En este trabajo se resume la aplicación del estudio analógico de los yacimientos de elementos radiactivos a la modelización y validación de los procesos de migración/retención de los radioisótopos artificiales de alta actividad, en un medio geológico. Las características geológicas, mineralógicas y geoquímicas del sistema granito-mineralización de uranio de El Berrocal sugieren que dicho sistema no puede considerarse como un análogo natural global de un almacenamiento de residuos radiactivos. Sin embargo, los procesos hidrotermales de baja temperatura que lo afectaron, incluido el que originó la mineralización uranífera, así como los de alteración supergénica, pueden considerarse como procesos geoquímicos análogos a los que podrían tener lugar en un almacenamiento de residuos radiactivos de alta actividad.

  6. Invasive placenta previa. Placental bulge with distorted uterine outline and uterine serosal hypervascularity at 1.5T MRI - useful features for differentiating placenta percreta from placenta accreta

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xin; Zhang, Xinjuan; Wang, Shanshan; Shi, Honglu; Gao, Fei; Wang, Guangbin [Shandong University, Department of MR, Shandong Medical Imaging Research Institute, Jinan, Shandong (China); Shan, Ruiqin [Jinan Maternity and Child Care Hospital, Department of Obstetrics, Jinan (China); Zhao, Lianxin [Qilu Hospital of Shandong University, Department of Radiology, Jinan, Shandong (China); Song, Qingxu [Qilu Hospital of Shandong University, Department of Radiation Oncology, Jinan, Shandong (China); Zuo, Changting [Shandong Provincial Hospital Affiliated to Shandong University, Department of Obstetrics and Gynaecology, Jinan, Shandong (China); Qian, Tianyi [MR Collaborations NE Asia, Siemens Healthcare, Beijing (China); Limperopoulos, Catherine [Children' s National Health System, Division of Diagnostic Imaging and Radiology, Washington, DC (United States); George Washington University School of Medicine, Department of Radiology, Washington, DC (United States)

    2018-02-15

    To characterise MRI features of invasive placenta previa and to identify specific features for differentiating placenta percreta (PP) from placenta accreta (PA). Forty-five women with PP and 93 women with PA who underwent 1.5T placental MRI were included. Two radiologists independently evaluated the MRI features of invasive placenta previa, including our novel type of placental bulge (i.e. placental bulge type-II, characterized by placental bulge with distorted uterine outline). Pearson's chi-squared or Fisher's two-sided exact test was performed to compare the MRI features between PP and PA. Logistic stepwise regression analysis and the area under the receiver operating characteristic curve (AUC) were performed to select the optimal features for differentiating PP from PA. Significant differences were found in nine MRI features between women with PP and those with PA (P <0.05). Placental bulge type-II and uterine serosal hypervascularity were independently associated with PP (odds ratio = 48.618, P < 0.001; odds ratio = 4.165, P = 0.018 respectively), and the combination of the two MRI features to distinguish PP from PA yielded an AUC of 0.92 for its predictive performance. Placental bulge type-II and uterine serosal hypervascularity are useful MRI features for differentiating PP from PA. (orig.)

  7. Invasive placenta previa: Placental bulge with distorted uterine outline and uterine serosal hypervascularity at 1.5T MRI - useful features for differentiating placenta percreta from placenta accreta.

    Science.gov (United States)

    Chen, Xin; Shan, Ruiqin; Zhao, Lianxin; Song, Qingxu; Zuo, Changting; Zhang, Xinjuan; Wang, Shanshan; Shi, Honglu; Gao, Fei; Qian, Tianyi; Wang, Guangbin; Limperopoulos, Catherine

    2018-02-01

    To characterise MRI features of invasive placenta previa and to identify specific features for differentiating placenta percreta (PP) from placenta accreta (PA). Forty-five women with PP and 93 women with PA who underwent 1.5T placental MRI were included. Two radiologists independently evaluated the MRI features of invasive placenta previa, including our novel type of placental bulge (i.e. placental bulge type-II, characterized by placental bulge with distorted uterine outline). Pearson's chi-squared or Fisher's two-sided exact test was performed to compare the MRI features between PP and PA. Logistic stepwise regression analysis and the area under the receiver operating characteristic curve (AUC) were performed to select the optimal features for differentiating PP from PA. Significant differences were found in nine MRI features between women with PP and those with PA (P Placental bulge type-II and uterine serosal hypervascularity were independently associated with PP (odds ratio = 48.618, P Placental bulge type-II and uterine serosal hypervascularity are useful MRI features for differentiating PP from PA. • Placental bulge type-II demonstrated the strongest independent association with PP. • Uterine serosal hypervascularity is a useful feature for differentiating PP from PA. • MRI features associated with abnormal vessels increase the risk of massive haemorrhage.

  8. Invasive placenta previa. Placental bulge with distorted uterine outline and uterine serosal hypervascularity at 1.5T MRI - useful features for differentiating placenta percreta from placenta accreta

    International Nuclear Information System (INIS)

    Chen, Xin; Zhang, Xinjuan; Wang, Shanshan; Shi, Honglu; Gao, Fei; Wang, Guangbin; Shan, Ruiqin; Zhao, Lianxin; Song, Qingxu; Zuo, Changting; Qian, Tianyi; Limperopoulos, Catherine

    2018-01-01

    To characterise MRI features of invasive placenta previa and to identify specific features for differentiating placenta percreta (PP) from placenta accreta (PA). Forty-five women with PP and 93 women with PA who underwent 1.5T placental MRI were included. Two radiologists independently evaluated the MRI features of invasive placenta previa, including our novel type of placental bulge (i.e. placental bulge type-II, characterized by placental bulge with distorted uterine outline). Pearson's chi-squared or Fisher's two-sided exact test was performed to compare the MRI features between PP and PA. Logistic stepwise regression analysis and the area under the receiver operating characteristic curve (AUC) were performed to select the optimal features for differentiating PP from PA. Significant differences were found in nine MRI features between women with PP and those with PA (P <0.05). Placental bulge type-II and uterine serosal hypervascularity were independently associated with PP (odds ratio = 48.618, P < 0.001; odds ratio = 4.165, P = 0.018 respectively), and the combination of the two MRI features to distinguish PP from PA yielded an AUC of 0.92 for its predictive performance. Placental bulge type-II and uterine serosal hypervascularity are useful MRI features for differentiating PP from PA. (orig.)

  9. Reseña: Abal Oliú, Alejandro: C.G.P. y conciliación previa en materia laboral, Editorial Universidad Ltda. Montevideo, 1992, 64 págs.

    Directory of Open Access Journals (Sweden)

    o. C. R.

    2015-10-01

    Full Text Available Abal Oliú, Alejandro: C.G.P. y conciliación previa en materia laboral, Editorial Universidad Ltda. Montevideo, 1992, 64 págs. Editorial Universidad Ltda. Montevideo, 1992, 64 págs.El autor, profesor de Derecho Procesal y de Técnica Forense en nuestra Facultad, analiza en la presente obra las distintas fórmulas que es posible estab~ecer en cuanto a la tentativa de conciliación previa a la iniciación de los procesos laborales, luego de la entrada en vigencia del Código General del Proceso. (...

  10. Distribución de uranio y torio en la apófisis adamellítica de Logrosán (Cáceres, España

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    Guijarro Galiano, J.

    1986-12-01

    Full Text Available Logrosan apophyses (Cáceres, España has two differents petrographic types: a porphyritic two mica adamellite and a porphyritiv two mica microadamellite. It's an alkaline with silico-sodic trend and peraluminous granitoid. A greisen alteration has been produced by the tin-veins in the host-rock.
    The moderatly high content values of uranium are ranged between 6.9 and 11.9 ppm, with a mean of 9.5 ppm. Thorium has lower concentrations levels. The Th/U ratio has an average value of 0.8.
    The fact that thorium ís correlated positivels with ferromagnesian elements indicates that is probably contained within the boitites.
    Higher thorium and uranium values are founded in the adamellite type.
    Greisen has produced an uranium leaching that would be important as uranium mineralization source outside the apophyses. Although has not been observed uranium mineralizations in the geological area study.

    La apófisis de Logrosán (Cáceres, España está constituida por una adamellita y una microdamellita, ambas de dos micas. Geoquímicamente presenta un carácter marcadamente alcalino, con una tendencia silicosódica clara, y peraluminoso. Los filones estanníferos existentes han producido una greisenificación en la roca encajante.
    El fondo geoquímico del uranio está comprendido entre 6,9 y 11,9 ppm, con un valor medio de 9,5 ppm, y es ligeramente superior al habitual para estos materiales. El fondo del torio es inferior y el valor medio de la relación Th/U es de 0,8.
    Existe una buena correlación positiva entre el torio y los elementos ferromagnesianos. Probablemente se encuentra asociado a las biotitas.
    Los fondos geoquímicos más altos, en torio y uranio, corresponden a la facies adamellítica.
    La greisenificación ha provocado una lixiviación de uranio que ha podido actuar como fuente para posibles mineralizaciones extraplutónicas, aunque en el estudio geológico de la zona no han sido

  11. Participación del consejo comunitario de la comunidad negra de Bellavista en la consulta previa para la formulación del plan de manejo ambiental de la central hidroeléctrica del bajo Anchicayá

    Directory of Open Access Journals (Sweden)

    Nixon Arboleda Montaño

    2016-01-01

    Full Text Available El presente trabajo analiza el proceso de participación que se llevó a cabo en el marco de la consulta previa entre el Consejo Comunitario de la Comunidad Negra de Bellavista (CCCNB, situado en el distrito de Buenaventura y la Empresa de Energía del Pacífico (EPSA con motivo de la formulación del Plan de Manejo Ambiental para la actual operación y mantenimiento la Central Hidroeléctrica del Bajo Anchicayá (Colombia. Se presentan los antecedentes de la evaluación de impacto ambiental en el ámbito internacional y en Colombia, y se explica en qué consiste el proceso de la consulta previa en los proyectos que requieren licencia ambiental. Posteriormente se analizan las etapas del proceso (etapa previa; estudios ambientales y socioeconómicos; identificación y evaluación de impactos ambientales; y construcción de medidas de manejo ambiental y finalmente se analiza el proceso de consulta previa, identificando los valores agregados que pudo generar el proceso.

  12. Ideas previas sobre carga, fuerza y campo eléctrico en estudiantes universitarios. Consideraciones para su superación

    Directory of Open Access Journals (Sweden)

    Marianela Nava

    2008-05-01

    Full Text Available El presente trabajo trata sobre el valor didáctico de las ideas previas de los estudiantes para la construcción de nuevos saberes, que lo posibiliten para dar explicaciones acordes con el conocimiento científico. Luego del análisis de los datos, se plantea el diseño de situaciones didácticas, fundamentadas en Posner et al, Ausubel, Amestoy, Alonso et al, que permitan promover la construcción de conceptos, aplicable a diversos campos. El estudio se encuentra enmarcado en un paradigma cuali-cuantitativo, a nivel descriptivo. Una conclusión importante es que las nociones sobre campo eléctrico, resultaron más deficientes que las de carga, pero menos que las de fuerza eléctrica, siendo necesario fomentar la construcción de conceptos científicos en los estudiantes universitarios.

  13. The Estimation of Internal Contamination with Uranium from Urine Analysis Results; Evaluation de la Contamination Interne par l'Uranium a Partir des Resultats de l'Analyse d'Urines; 041e 0426 0414 ; Evaluacion de la Contaminacion Interna con Uranio a Partir de los Resultados del Analisis de Orina

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, S. [Authority Health and Safety Branch, Radiological Protection Division, United Kingdom Atomic Energy Authority, Harwell, Berks. (United Kingdom)

    1964-11-15

    consideration principale dont il faut tenir compte est d'ordre non pas radiologique mais toxicologique, en raison des effets chimiques que produit l'uranium depose dans les reins. Une certaine quantite d'uranium se depose egalement dans le squelette mais, dans le cas de l'uranium naturel, la radioexposition du squelette est moins critique que des effets toxiques sur les reins. Dans le cas de composes solubles de l'uranium fortement enrichi ayant une activite specifique elevee, la consideration principale est d'ordre radiologique; les effets chimiques sur les reins sont moins limitatifs que la radioexposition du squelette, qui devient ainsi l'organe critique. Dans ce cas, il vaut mieux essayer d'evaluer la charge corporelle retenue et non la quantite d'uranium absorbee. On peut y parvenir en analysant des echantillons d'urines prelevees, non pas immediatement apres la contamination, mais apres un certain delaL Les echantillons preleves apres une periode de vacances sont probablement les meilleurs que l'on puisse obtenir en pratique, mais on peut avoir a se contenter d'echantillons preleves apres le repos hebdomadaire qui suit une semaine de travail dans une atmosphere chargee de poussieres d'uranium. (author) [Spanish] La causa mas corriente de contaminacion interna con uranio es la inhalacion de polvo de este elemento. Los compuestos solubles de uranio pasan rapidamente de los pulmones a la sangre y la mayor parte del uranio que penetra en el torrente circulatorio es excretado muy pronto por via urinaria. La cantidad de uranio soluble absorbida en el curso del trabajo se puede calcular a partir del contenido en uranio de muestras de orina tomadas inmediatamente despues del mismo. Los compuestos'solubles de uranio natural se caracterizan por el hecho de que la consideracion primordial no es de orden radiologico sino toxicologico, debido a los efectos quimicos del uranio depositados en los rinones Parte del uranio se deposita tambien en el esqueleto, pero la irradiacion del

  14. Evaluación Médica Previa a La Práctica Deportiva Para Deportistas Aficionados y de Nivel Competitivo

    Directory of Open Access Journals (Sweden)

    Dr. D. Fernando yáñez

    2012-05-01

    Full Text Available La actividad física y el deporte reducen la mortalidad general y cardiovascular, pero durante la práctica de ejercicio aumenta el riesgo de muerte súbita que puede ser la primera manifestación de una enfermedad cardiovascular no diagnosticada en deportistas previamente asintomáticos. Las causas de muerte súbita difieren según la edad, en los menores de 35 años se debe a patologías congénitas o hereditarias y en los mayores de esta edad a enfermedad coronaria. En el presente artículo se analizan las causas más frecuentes de muerte súbita, así como los protocolos de evaluación médica previa a la práctica de actividad física o deporte propuestos en la literatura para su prevención en deportistas de diferentes edades y nivel de actividad, desde el competitivo de alto rendimiento hasta el recreativo por salud, y utilización del tiempo libre.

  15. Uranium Ore and Concentrate Sampling; Echantillonnage des Minerais et des Concentres d'Uranium; Otbor prob uranovoj rudy i kontsentratov; Muestreo de Minerales y Concentrados de Uranio

    Energy Technology Data Exchange (ETDEWEB)

    McGinley, F. E.; Brown, D. L.; Langridge, R. W. [United States Atomic Energy Commission, Grand Junction, CO (United States)

    1966-02-15

    dirigees par des exploitants sous contrat. Un lot moyen comprend environ 50 futs (de 210 litres) et pese environ 16 tonnes. Comme les caracteristiques physiques et chimiques de ces concentres varient considerablement d'un fut a l'autre, il est necessaire d'echantillonner chaque fut. Au cours de ces annees, on a eu recours a differents procedes d'echantillonnage - tubes, sondes ouvertes, sondes fermees ou ecoulement du minerai. Ce dernier procede est le plus precis a condition que l'on prenne les precautions requises pour prevenir les changements de poids resultant de l'exposition a l'atmosphere. Comme les concentres ont tendance a absorber l'humidite ambiante ou a perdre leur humidite selon les conditions atmospheriques auxquelles ils sont exposes, on a constamment mis au point des methodes speciales de sous-echantillonnage, de sechage et de preparation des echantillons en vue de rendre l'echantillonnage de tous les lots plus exact et plus precis. On a eu beaucoup recours a la statistique pour analyser et interpreter les mesures et les donnees pour l'evaluation des echantillonnages. (author) [Spanish] La oficina de Grand Junction de la Comision de Energia Atomica de los Estados Unidos ha tenido que adquirir grandes cantidades de uranio natural, tanto en forma de mineral como en forma de concentrado. Las tecnicas empleadas para el muestreo de minerales difieren necesariamente de las empleadas para los concentrados. Los autores de la memoria analizan las operaciones que integran los sistemas generales de medicion y muestreo de minerales y concentrados, prestando atencion especial a la exactitud y precision de cada una de ellas. Entre 1948 y 1964 se sacaron muestras de 58 millones de toneladas de mineral en unas 40 plantas de muestreo mecanico situadas en la parte occidental de los Estados Unidos. En todas estas plantas el mineral fue pesado, muestreado y analizado segun practicas aprobadas por la AEC de los Estados Unidos. Para las muestras se siguieron los principios

  16. CONSIDERACIONES PREVIAS A LA ANTIBIOTICOTERAPIA

    Directory of Open Access Journals (Sweden)

    Moisés Morejón García

    2004-01-01

    Full Text Available Exponemos y valoramos los aspectos más sobresalientes a tener en cuenta antes de la aplicación de una terapia con fármacos antimicrobianos. La violación de estos aspectos puede, en muchas ocasiones, provocar el uso inadecuado de los mismos, lo que puede conllevar a un fallo de la farmacoterapia esperada, al surgimiento o incremento de resistencia bacteriana, así como a la aparición de efectos adversos evitables.

  17. Problems of Uranium Monocarbide and Mononitride Technology; Problemes de la technologie des monocarbures et mononitrures d'uranium; Problemy tekhnologii monokarbida i mononitrida urana; Problemas de la tecnologia del monocarburo y del mononitruro de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Yakeshova, L. [Institut Yadernykh Issledovanij Chekhoslovatskoj, Czechoslovak Socialist Republic (Czech Republic)

    1963-11-15

    A critical account of published data is given, and the over-all demands made on ceramic nuclear fuel of the uranium monocarbide and mononitride type are examined. The paper also refers to a number of still unsolved problems, either at the research level or at that of practical application. A short account is given of methods of obtaining monocarbide and preparing compacted products. (author) [French] Le memoire donne un apercu critique de la documentation publiee. Il examine les criteres generaux auxquels doit repondre le combustible nucleaire ceramique du type monocarbure et mononitrure d'uranium. Il indique les problemes qui se posent encore en ce qui concerne les travaux de recherche ou l'utilisation pratique des matieres. Les methodes de preparation des monocarbures et les questions relatives a la fabrication de produits compacts font l'objet d'un bref examen. (author) [Spanish] La memoria examina criticamente los datos publicados. Se exponen los requisitos generales de los combustibles nucleares ceramicos del tipo monocarburo y mononitruio de uranio. Se senalan los problemas aun no resueltos en lo relativo a los trabajos de investigacion o a las aplicaciones practicas de esos materiales. Se describen brevemente los metodos de preparacion de los monocarburos y los problemas que plantean la elaboracion de productos compactos. (author) [Russian] Daetsya kriticheskoe obsuzhdenie literaturnykh dannykh. Razbirayutsya obshchie trebovaniya k keramicheskomu yadernomu toplivu tipa monokarbida i mononitrida urana. Otmechayutsya problemy, kotorye s tochki zreniya issledovatel'skikh rabot ili prakticheskogo primeneniya materialov, ostayutsya eshche ne reshennymi. Kratko obsuzhdayutsya metoda polucheniya monokargida i voprosy prigotovleniya kompaktnykh izdelij. (author)

  18. Ideas previas sobre el reino vegetal en niños entre los 7 y 10 años de tercero de primaria de la Escuela Normal Superior Distrital María Montessori (E.N.S.D.M.M.)

    OpenAIRE

    Daniela Gomez; Daniela Velasco

    2015-01-01

    La presente investigación busca reconocer las ideas previas sobre el reino vegetal en niños entre los 7 y 10 años. Se eligió un grupo de 37 estudiantes de tercero de primaria perteneciente a la E.N.S.D.M.M., con los cuales se implementó un instrumento de caracterización tipo cuestionario conformado por 3 preguntas referentes al reino vegetal. A partir de las respuestas dadas por los niños, se clasificaron sus ideas previas generando categorías de estas, posterior a ello, con la referencia de ...

  19. Relación entre la autonomía y las experiencias educativas previas de los actores curriculares encontradas en un contexto de educación superior de Bogotá, Colombia

    Directory of Open Access Journals (Sweden)

    Hélder Barahona Urbano

    2011-01-01

    universitarios sobre la autonomía en los procesos de aprendizaje y enseñanza, en el programa académico de Administración de Empresas, de la jornada diurna? La metodología que utilizó fue cualitativa, con enfoque etnográfico crítico; corresponde a la línea de investigación que se denomina ¿Pedagogía y Didáctica¿. Los resultados describen las relaciones que existen entre las creencias y las experiencias educativas previas, de los actores curriculares sobre la autonomía en los procesos de enseñanza y aprendizaje. Se concluye que relaciones pedagógicas establecidas en los procesos educativos afectan directamente la autonomía.

  20. New Phase in the System Uranium-Molybdenum-Silicon; Nouvelle phase dans le systeme uranium-molybdene-silicium; Novaya faza v sisteme uran-molibden'-kremnij; Una fase nueva en el sistema uranio-molibdeno-silicio

    Energy Technology Data Exchange (ETDEWEB)

    Sikirica, M.; Ban, Z. [Rudjer Bokovic Institute, Zagreb, Yugoslavia (Croatia)

    1963-11-15

    During the investigation of the ternary system uranium-molybdenum-silicon, a new phase with the composition U{sub 4}Mo{sub 5}-Si{sub 3} was formed. Structure determination exclusively based on the powder data showed that the particular phase belongs to the hexagonal system. Space group P6/mmc or one of the sub-groups is indicated. Unit cell dimensions were found to be a = 5.37{sub 0}A, c = 8 . 58{sub 2}A. A comparison of calculated and observed intensities shows close resemblance to the structure of the Laves phases of the C14-type. (author) [French] Au cours de recherches sur le systeme ternaire uranium-molybdene-silicium, on a constate la formation d'une nouvelle phase, de composition U{sub 4}Mo{sub 5}Si{sub 3}. Une determination de la structure, exclusivement fondee sur des donnees relatives a la poudre, a revele que cette phase particuliere appartenait au systeme hexagonal. Les auteurs indiquent un groupe spatial P6/mmc ou un des sous-groupes. Les dimensions d'une maille individuelle sont donnees par a = 5,37{sub 0}A, c = 8,58{sub 2}A. La comparaison entre l'intensite calculee et Tintensite observee montre une ressemblance etroite avec la structure des phases de Laves du type C-14. (author) [Spanish] En-el curso del estudio del sistema temario uranio-molibdeno-silicio, los autores observaron la formacion de una fase cuya composicion responde a la formula U{sub 4}Mo{sub 5}Si{sub 3}. La determinacion de la estructura, basada exclusivamente en los datos referentes al material en polvo, demuestra que esa fase pertenece al sistema hexagonal. Se senalo la existencia de un grupo especial P6/mmc y se comprobo que las dimensiones de la celda elemental son a = 5,37{sub 0}A, c = 8,58{sub 2}A. La comparacion de las intensidades calculadas con las observadas indica que existe una analogia estrecha con la estructura de la fase de Laves del tipo C 14. (author) [Russian] Pri izuchenii trojnoj sistemy uran - molibden - kremnij obrazovalas' novaya faza sostava U{sub 4}Mo{sub 5

  1. Tritium Labelling by Means of Uranium Hydride; Marquage au Tritium au Moyen d'Hydrure d'Uranium; 0414 0435 0447 ; Marcacion con Tritio por Medio de Hidruro de Uranio

    Energy Technology Data Exchange (ETDEWEB)

    Felter, R. E.; Currie, L. A. [Pennsylvania State University, University Park, PA (United States)

    1962-02-15

    exponiendo la sustancia organica en fase vapor al tritiuro de uranio caliente. En los experimentos realizados con n-pentano y con etileno, se obtienen como principal producto las moleculas originales tritiadas. Las velocidades de incorporacion del tritio oscilaron entre el 0,2 y el 10 por ciento (del tritio inicial) por hora. Los autores han demostrado que la reaccion no se debe a efectos quimicos de las radiaciones, sino que se produce directamente entre los atomos de tritio de la superficie y el hidrocarburo. Ademas de aprovechar rapidamente en la marcacion una parte considerable del tritio presente, el metodo ofrece otra ventaja notable por la facilidad con que por simple enfriamiento del aparato hasta la temperatura ambiente, se puede eliminar de la fase gaseosa el tritio que no haya reaccionado con los vapores del hidrocarburo. (author) [Russian] Rassmatrivaetsja novyj i -jeffektivnyj metod vvedenija tritija v organicheskie molekuly. Mechenie pro- izvoditsja oblucheniem organicheskih parov s pomoshh'ju nagretogo tritidachrana. Pri opytah s n-pentanom i jetilenom glavnymi mechenymi produktami byli tritiro- vannye materinskie molekuly. Stepen pogloshhenija tritija kolebalas' pri- merno ot 0,2 do 10,0% (pervonachal'nogo kolichestva tritija) v chas. Bylo pokazano, chto mehanizm reakcii ne javljaetsja rezul'tatom radiacionnoj himii, a skoree prjamoj reakciej atomov vodoroda s poverhnosti s uglevodoro- dom. Pomimo bystrogo mechenija znachitel'noj ' dolej prisutstvujushhego tritija metod imeet eshhe odno unikal'noe dostoinostvo: tritij, ne vstupivshij v reak- ciju s organicheskim parom, legko ustranjaetsja iz gazovoj fazy prostym ohlazhde- niem reaktivnogo sosuda do komnatnoj temperatury. (author)

  2. La educación y la salud como coberturas previas a aplicación de la tabla de pensiones alimenticias básicas para niños, niñas y adolescentes

    Directory of Open Access Journals (Sweden)

    Juan Martínez Yntriago

    2015-11-01

    Full Text Available En Ecuador se usa lo coercitivo de la ley para hacer cumplir el derecho de niños, niñas y adolescentes a la manutención por parte de sus padres y familiares cercanos; con este objetivo, se creó la Tabla de Pensiones Alimenticias Básicas para ser aplicada obligatoriamente en los juicios de alimentos respecto al ingreso del alimentante, sin considerar necesidades que previamente son cubiertas y que no deben ser parte del reclamo; por lo cual, esta investigación hace una revisión a la teoría del derecho de alimentos y un análisis de la cobertura previa de educación y salud que no son apreciadas al momento de imponer la pensión alimenticia, así como una crítica a la aplicación de la referida tabla por la variación de los aspectos que motivaron su creación y un trabajo de campo que permitió concluir que estas coberturas anticipadas continúan siendo reclamadas por quienes demandan alimentos para sus hijos.

  3. Determination of the Uranium Content of Aluminium Alloys; Determination de la Teneur en Uranium dans les Alliages a Base d'Aluminium; Opredelenie soderzhaniya urana v splavakh na osnove alyuminiya; Determinacion del Contenido de Uranio en las Aleaciones a Base de Aluminio

    Energy Technology Data Exchange (ETDEWEB)

    Gerard, J.; Van Hove, L. [S.A. Metallurgie et Mecanique Nucleaires Dessel (Belgium)

    1965-09-15

    exact de la teneur en {sup 235}U. En conclusion, on montre que la mesure de la teneur en uranium doit se faire en plusieurs etapes faisant intervenir toutes les ressources de methodes relativement simples. On indique la valeur et les limites de chaque etape. Le choix des etalons est base sur l'examen de cliches radiographiques. La mesure de leur teneur exacte en {sup 235}U est effectuee grace a des analyses chimiques et isotopiques. Le controle en cadence industrielle est realise par mesure de densite de l'alliage ou par comptage de l'emission gamma de {sup 235}U. La precision des deux methodes est comparable ({+-} 0,5% relatif). Au point de vue economique, on en arrive a recommander la determination de la teneur par comptage gamma chaque fois qu'une grande serie d'examens est necessaire sur des pieces de forme determinee. Ce sujet a deja ete traite. Le memoire relate et discute les resultats d'une experience industrielle. (author) [Spanish] Muchos reactores para ensayo de materiales utilizan como combustible una aleacion de aluminio y de uranio enriquecido. Es necesario conocer con precision la cantidad de uranio-235 contenida en cada elemento combustible. Los procedimientos utilizados para esa determinacion son en principio sencillos y ademas variados; pueden citarse los siguientes: la medicion de la densidad de la aleacion, el recuento de la emision gamma del uranio- 234, el analisis quimico, la determinacion del contenido isotopico y la evaluacion del ennegrecimiento de una placa radiografica. Por desgracia cada uno de esos metodos ofrece inconvenientes mas o menos graves cuando se los utiliza para controlar una produccion importante. La medicion de la densidad de la aleacion por el metodo de Arquimedes da resultados bastante precisos cuando se procede con cautela y cuando se conoce con exactitud la densidad de los metales que constituyen la aleacion. Ahora bien, las condiciones en que se realiza la operacion hacen que el metodo sea algo lento. Ademas, es necesario

  4. Ideas Previas Acerca de “Evolución y Su Relación con la Genética” en Estudiantes de Grado Noveno del Colegio Nicolás Esquerra

    Directory of Open Access Journals (Sweden)

    Sergio Alejandro Peláez Plazas

    2015-12-01

    Full Text Available Como primera experiencia didáctica, en este trabajo se muestran las ideas previas que construyen 10  estudiantes de noveno grado del colegio Nacional Nicolás Esguerra acerca del proceso de evolución, las cuales se encuentran relacionadas con algunos conceptos que aborda la genética. Los datos fueron recogidos por medio de una encuesta de pregunta abierta y un dibujo en base al método cualitativo, con el fin de conocer la comprensión que los estudiantes tienen acerca de la evolución y  los conceptos mencionados en sus explicaciones, entre los cuales se encontraron: adaptación, ADN y código genético,  relacionando en estos el tiempo como factor de cambio. Estas ideas se organizaron en tres categorías  (Comprensión de Procesos evolutivos basados en variabilidad y selección natural e Ideas relacionadas al catastrofismo como factor promotor de especiación. Entre estas, la mayoría de los alumnos hace alusión a cambios en el ciclo de vida y desarrollo, y no como un proceso a nivel histórico y constante en las poblaciones. En cuanto a la comprensión del ADN, el gen y su relación con las especies, no hay claridad con respecto a la expresión de caracteres desde  la información que se expresa en las proteínas. Por consiguiente, se infiere que las ideas encontradas están poco articuladas  ya que ellos no las logran conectar de forma apropiada en sus respuestas.

  5. Preparation of Ceramic-Grade Thorium-Uranium Oxide; Preparation d'un melange d'oxydes de thorium et d'uranium propre a la fabrication de combustible ceramique; Izgotovlenie keramicheskogo torievo-uranovogo okisla; Preparacion de mezclas de oxidos de uranio y torio, de tipo ceramico

    Energy Technology Data Exchange (ETDEWEB)

    Cogliati, G.; De Leone, R.; Ferrari, S.; Gabaglio, M.; Liscia, A. [Centro Studi Nucleari della Casaccia, Rome (Italy)

    1963-11-15

    que pour le recyclage de matieres de ce genre. Le procede consiste tout d'abord a reduire le nitrate d'uranyle en nitrate d'uranium (IV). On utilise comme agents reducteurs de l'hydrogene gazeux et de l'acide formique; on ajoute de l'uree pour prevenir la formation d'acide nitreux qui catalyse la reoxydation de l'uranium (IV). On peut employer comme catalyseurs le platine et le palladium. Les auteurs donnent des indications sur un processus continu au cours duquel on ajoute de l'acide formique et de l'uree a la solution qui est ensuite rechauffee avant d' etre passee dans une colonne remplie de.pastilles d'a lumine de 3,17 x 3,17 mm contenant 0,5% en poids de platine. Ils fournissent egalement des renseignements sur l'influence du debit, de la temperature et de la concentration de l'acide formique et de l'uree, ainsi que sur la duree de vie du catalyseur et l'empoisonnement. La precipitation d'un oxalate de thorium et d'uranium(IV) constitue la deuxieme phase. Les auteurs mentionnent l'influence de l'acide oxalique sur le rapport thorium/uranium, ainsi que ce l le de la temperature et du vieillissement surtles caracteristiques de la precipitation et du filtrage et sur les proprietes ceramiques des poudres obtenues. La mise a feu a ete faite dans une atmosphere reductrice et dans une atmosphere oxydante. Ces essais preliminaires ont abouti a la mise au point de deux methodes normalisees pour la fabrication d'elements ceramiques, a savoir la methode du pressage a froid puis frittage et la methode par extrusion et frittage. L'aptitude au frittage des differentes poudres a fait l'objet d'essais selon les deux methodes susmentionnees. Avec certaines des poudres, on a obtenu des densites depassant 95% de la valeur theorique; des essais de reproductibilite ont ete concluants. (author) [Spanish] Los autores han estudiado un metodo para preparar cuerpos sinterizados, compuestos por una mezcla de oxido de torio y uranio, a partir de una solucion de nitrato de torio y de nitrato

  6. The Determination of Uranium in Urine by Delayed Neutron Counting; Dosage de l'Uranium dans l'Urine par Comptage des Neutrons Differes; Opredelenie soderzhaniya urana v moche putem scheta zapazdyvayushchikh nejtronov; Determinacion del Uranio Contenido en la Orina por Recuento de Neutrones Retardados

    Energy Technology Data Exchange (ETDEWEB)

    Brookes, I. R. [Atomic Weapons Research Establishment, Aldermaston, Berks. (United Kingdom)

    1965-10-15

    polyethylene d'une capacite de 2,85 cl, qui est scelle a chaud. Le flacon contenant l'echantillon est enferme dans un tube et envoye par un systeme pneumatique dans le coeur du reacteur HERALD ou il est irradie par un fieux de neutrons thermiques de 3,94 * 10{sup 12}n/cm{sup 2}s. Apres une irradiation de 1 min, l'echantillon retourne automatiquement au laboratoire ou le flacon contenant l'echantillon est place dans un compteur a neutrons. Ce compteur est mis en marche 25 s apres que l'echantillon a quitte le reacteur et compte l'echantillon pendant 1 min. Les echantillons temoins se composent d'urine provenant de personnes qui ne sont pas professionnellement exposees a l'uranium; l'etalon est une quantite connue de {sup 235}U (sous forme d'uranium naturel). La limite de detection est de 0,020 pCi d'uranium enrichi a 93% ou de 0,026 {mu}g d'uranium naturel (0,007 de la charge corporelle maximale admissible) et de 0,036 {mu}g d'uranium naturel pour 100 ml d'urine. Elle depend du nombre de coups correspondant aux temoins. La composante principale du temoin est la reponse du compteur aux rayons gamma emis par les produits d'activation que l'urine irradiee contient. Il faut 3,5 min environ pour irradier et compter un echantillon et l'on peut, au cours d'une journee de travail, faire evaporer et traiter 50 echantillons pour les mettre en flacons. Pour les analyses d'urine, l'influence de {sup 239}Pu peut etre consideree comme negligeable. (author) [Spanish] Con arreglo al metodo del autor, el uranio-235 se determina por recuento de los neutrones retardados emitidos a raiz de la fision por neutrones termicos del {sup 235}U contenido en la muestra. Los tres grupos de neutrones que se consideran tienen periodos de 55, 72, 22, 72 y 6, 22 s, respectivamente. En un bano Maria se evaporan a sequedad 100 mi de orina. El residuo se pasa con unos 4 a 5 mi de agua a un frasco de polietileno de 1 onza, que se cierra seguidamente por soldadura termica. El frasco con la muestra se coloca en un

  7. Hematometra following caesarean section for placenta previa

    African Journals Online (AJOL)

    2017-12-08

    Dec 8, 2017 ... to surgical procedures such as cone biopsy. Hematometra following ... Subharti Medical College, Meerut, India, with abdominal pain for the previous 3 ... spinal anaesthesia, the vagina was visualised with the help of two.

  8. territorial previa a la toma de decisiones

    Directory of Open Access Journals (Sweden)

    Ángel Raúl Ruiz Pulpón

    2006-01-01

    Full Text Available La expansión de la agricultura de regadío ha ocasionado una signifi cativa confl ictividad ecológica, económica y social concerniente al uso del agua en la cuenca del Guadiana. Ante la ausencia, en estos últimos treinta años, de enfoques territoriales y sistémicos para la resolución de la problemática, se propone una metodología que permite la clasifi cación territorial de los municipios de la cuenca hidrográfi ca del Guadiana que presenten unas características similares de sus regadíos, con el objeto de plantear un modelo espacial previo a la toma de decisiones sobre la gestión de los recursos hídricos, agrarios y ambientales en Castilla-La Mancha, en consonancia con los preceptos estipulados por la Directiva Marco de Aguas y la Estrategia Territorial Europea

  9. A Contribution to the Study of the Oxidation of Uranium Monocarbide in Carbonic Anhydride at High Temperatures; Contribution a l'etude de l'oxydation du monocarbure d'uranium dans l'anhydride carbonique aux temperatures elevees; Vklad v izuchenie voprosa okisleniya monokarbida urana v ugol'nom angidride pri povyshennykh temperaturakh; Contribucion al estudio de la oxidacion del monocarburo de uranio en anhidrido carbonico a temperaturas elevadas

    Energy Technology Data Exchange (ETDEWEB)

    Desrues, R; Paidassi, J.; Darras, R. [Centre d' Etudes Nucleaires, Saclay (France)

    1963-11-15

    fragmentation progressive des echantillons. Les augmentations de poids trouvees sont d'ailleurs nettement plus faibles que celles publiees jusqu'a ce jour, ce qu'il faut tres vraisemblablement attribuer a une purete plus grande de l'anhydride carbonique mis en oeuvre et a une porosite particulierement faible du monocarbure d'uranium utilise. 2. La presence d'inclusions dans le monocarbure, qu'elles correspondent a de l'uranium ou a du dicarbure, diminue la resistance a.l'oxydation de ce materiau, ce qu'il faut surtout imputer au fait que celles-ci subissent une oxydation catastrophique, notamment par suite des contraintes mecaniques qu' elles introduisent. 3. Dans tous les cas, le processus d'oxydation peut etre caracterise par une energie d'activation egale a 29 000 cal/mole, valeur tres voisine de celle qui correspond a l'oxydation de l'uranium metallique dans le meme gaz, et a la diffusion de l'oxygene dans l'oxyde d'uranium (UO{sub 2}) forme. (author) [Spanish] Los autores tomaron muestras de monocarburo de uranio, obtenidas por dos procedimientos distintos, y de un cermet compuesto de 96,7% de U y 3,3% de C (en peso), las sometieron a la accion del anhidrido carbonico practicamente exento de oxigeno y vapor de agua, en un intervalo de temperaturas de 350 a 600 deg. C; observaron el progreso de la oxidacion por gravimetria (con una termobalanza de Eyraud) y por micrografia a la vez. Llegaron a las siguientes conclusiones: 1. Al principio, las graficas que representan los aumentos de peso en funcion del tiempo son sensiblemente rectilineas, pero luego su pendiente se acentua, lo que se explica sobre todo por la fragmentacion progresiva de las muestras. Por otra parte, los aumentos de peso verificados son netamente inferiores a los datos publicados hasta el presente, lo que cabe atribuir muy probablemente a la mayor pureza del anhidrido carbonico utilizado y a la porosidad particularmente baja del monocarburo de uranio empleado. 2. La presencia de inclusiones en el

  10. Pulsed Source Measurements on a Uranium-Water Subcritical Assembly; Mesures Faites sur un Assemblage Sous- Critique Uranium-Eau Ordinaire a l'Aide d'une Source Pulsee; Izmereniya s pomoshch'yu istochnikov impul'snykh nejtronov na urano-vodnoi podkriticheskoi sborke; Mediciones con Fuentes Pulsantes en un Conjunto Subcritico Uranio-Agua

    Energy Technology Data Exchange (ETDEWEB)

    Gibson, I. H.; Walker, J. [Department of Physics, University of Birmingham, Birmingham (United Kingdom)

    1964-02-15

    An unreflected assembly of natural uranium and light water has been used in conjunction with a pulsed source of neutrons for decay-time measurements at different bucklings. Four different lattice pitches over the range 3.94 cm to 5.08 cm were obtained by using different pairs of accurately machined lattice plates and in each case the uranium was in the form of bars 109.8 cm long and 3.0 cm diameter. The fuel- was mounted horizontally and loadings up to approximately 6 t were involved. Spatial harmonics were eliminated or selected by appropriate placing of a small scintillation detector. Experimental results showing the dependence of decay constant on buckling are presented and compared with theoretical values. (author) [French] On a utilise conjointement un assemblage sans reflecteur uranium naturel-eau ordinaire et une source puisee en vue de mesurer le temps de decroissance pour differents laplaciens. - Plusieurs paires de plaques de reseau usinees avec precision ont permis d'adopter quatre differents pas de reseau allant de 3,94cm a 5,08 cm; dans chaque cas, l'uranium etait sous forme de barres de 109,8 cm de long et de 3,0 cm de diametre. Le combustible etait monte horizontalement et le chargement a atteint parfois jusqu'a pres de 6 t. Grace a un petit detecteur a scintillations convenablement place, on a pu eliminer les harmoniques spatiaux ou les selectionner. Les auteurs presentent des resultats d'experiences qui montrent les variations de la constante de desintegration en fonction du laplacien, et les comparent avec les valeurs theoriques. (author) [Spanish] Los autores utilizaron un conjunto de uranio natural y agua ligera, sin reflector, juntamente con una fuente neutronica pulsante, para efectuar determinaciones del tiempo de desintegracion en correspondencia con diferentes valores del laplaciano. En este conjunto se pueden establecer cuatro diferentes espaciamientos del reticulado, desde 3,94 cm hasta 5,08 cm. utilizando diferentes pares de placas de

  11. Communication Received from Germany Concerning its Policies regarding the Management of Plutonium. Statements on the Management of Plutonium and of High Enriched Uranium; Comunicacion recibida de Alemania en relacion con sus politicas referentes a la gestion del plutonio. Declaraciones sobre la gestion del plutonio y del uranio muy enriquecido

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-27

    The Director General has received a note verbale dated 29 April 2011 from the Permanent Mission of the Federal Republic of Germany to the IAEA in enclosures of which the Government of Germany, in keeping with its commitment under the Guidelines for the Management of Plutonium (contained in INFCIRC/5491 of 16 March 1998 and hereinafter referred to as the 'Guidelines'), and in accordance with Annexes B and C of the Guidelines, has made available annual figures for holdings of civil unirradiated plutonium and the estimated amounts of plutonium contained in spent civil reactor fuel as of 31 December 2010. The Government of the Federal Republic of Germany has also made available a statement of its annual figures for holdings of civil high enriched uranium (HEU) as of 31 December 2010 [Spanish] El Director General ha recibido una nota verbal, de fecha 29 de abril de 2011, de la Mision Permanente de la Republica Federal de Alemania ante el OIEA, en cuyos anexos el Gobierno de Alemania, en cumplimiento de su compromiso contraido en virtud de las Directrices para la gestion del plutonio (transcritas en el documento INFCIRC/5491 de 22 de junio de 1998 y en adelante denominadas las 'directrices'), y de conformidad con los anexos B y C de las directrices, presenta las cifras anuales de sus existencias de plutonio no irradiado de uso civil y las cantidades estimadas de plutonio contenido en el combustible gastado de reactores de uso civil, a 31 de diciembre de 2010. El Gobierno de la Republica Federal de Alemania tambien ha presentado un estado de sus existencias anuales de uranio muy enriquecido (UME) de uso civil, a 31 de diciembre de 2010.

  12. Communication Received from Germany Concerning its Policies regarding the Management of Plutonium. Statements on the Management of Plutonium and of Highly Enriched Uranium; Comunicacion recibida de Alemania en relacion con sus politicas referentes a la gestion del plutonio. Declaraciones sobre la gestion del plutonio y del uranio muy enriquecido

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-09-04

    The Director General has received a Note Verbale dated 3 July 2007 from the Permanent Mission of the Federal Republic of Germany to the IAEA in the enclosures of which the Government of Germany, in keeping with its commitment under the Guidelines for the Management of Plutonium (contained in INFCIRC/549 of 16 March 1998 and hereinafter referred to as the 'Guidelines'), and in accordance with Annexes B and C of the Guidelines, has made available annual figures for holdings of civil unirradiated plutonium and the estimated amounts of plutonium contained in spent civil reactor fuel as of 31 December 2006. The Government of the Federal Republic of Germany has also made available a statement of its annual figures for holdings of civil highly enriched uranium (HEU) as of 31 December 2006 [Spanish] El Director General ha recibido una nota verbal, de fecha 3 de julio de 2007, de la Mision Permanente de la Republica Federal de Alemania ante el OIEA, en cuyos anexos el Gobierno de Alemania, en cumplimiento de su compromiso contraido en virtud de las Directrices para la gestion del plutonio (transcritas en el documento INFCIRC/549 de 16 de marzo de 1998 y en adelante denominadas 'las Directrices') y de conformidad con los Anexos B y C de las Directrices, ha presentado las cifras anuales de sus existencias de plutonio no irradiado de uso civil y las cantidades estimadas de plutonio contenido en el combustible gastado de reactores de uso civil, al 31 de diciembre de 2006. El Gobierno de la Republica Federal de Alemania tambien ha presentado una declaracion relativa a las cifras anuales de sus existencias de uranio muy enriquecido (UME) de uso civil, al 31 de diciembre de 2006.

  13. Communication Received from Germany Concerning its Policies regarding the Management of Plutonium. Statements on the Management of Plutonium and of High Enriched Uranium; Comunicacion recibida de Alemania en relacion con sus politicas referentes a la gestion del plutonio. Declaraciones sobre la gestion del plutonio y del uranio muy enriquecido

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-11-02

    The Director General has received a letter dated 16 July 2009 from the Permanent Mission of the Federal Republic of Germany to the IAEA in enclosures of which the Government of Germany, in keeping with its commitment under the Guidelines for the Management of Plutonium (contained in INFCIRC/5491 of 16 March 1998 and hereinafter referred to as the 'Guidelines'), and in accordance with Annexes B and C of the Guidelines, has made available annual figures for holdings of civil unirradiated plutonium and the estimated amounts of plutonium contained in spent civil reactor fuel as of 31 December 2008. 2. The Government of the Federal Republic of Germany has also made available a statement of its annual figures for holdings of civil high enriched uranium (HEU) as of 31 December 2008 [Spanish] El Director General ha recibido una carta de fecha 16 de junio de 2009 dirigida al OIEA por la Mision Permanente de la Republica Federal de Alemania, en cuyos anexos el Gobierno de Alemania, en cumplimiento de su compromiso contraido en virtud de las Directrices para la gestion del plutonio (transcritas en el documento INFCIRC/5491 de 16 de marzo de 1998 y en adelante denominadas 'Directrices') y, de conformidad con los Anexos B y C de las Directrices, ha presentado las cifras anuales de sus existencias de plutonio no irradiado de uso civil y las cantidades estimadas de plutonio contenido en el combustible gastado de reactores de uso civil, al 31 de diciembre de 2008. El Gobierno de la Republica Federal de Alemania tambien ha presentado una declaracion relativa a las cifras anuales de sus existencias de uranio muy enriquecido (UME) de uso civil, a 31 de diciembre de 2008.

  14. Preparation of Uranium Dioxide by Electrochemical Reduction in Ammonium Carbonate Solutions and Subsequent Precipitation; Preparation de bioxyde d'uranium par reduction electrochimique dans des solutions de carbonate d'ammonium et precipitation; Prigotovlenie dvuokisi urana metodom ehlektrokhimicheskogo vosstanovleniya v rastvore karbonata ammoniya s posleduyushchim osazhdeniem; Preparacion de dioxido de uranio por reduccion electroquimica en soluciones de carbonato amonico u precipitacion subsiguiente

    Energy Technology Data Exchange (ETDEWEB)

    Pravdic, V.; Branica, M.; Pucar, Z. [Department of Physical Chemistry, Rudjer Boskovic Institute, Zagreb, Yugoslavia (Serbia)

    1963-11-15

    tecnologicos. Se construyo una celda electrolitica de cloruro de polivinilo duro con catodo de mercurio de aproximadamente 2,5dm{sup 2} de superficie y anodos de platino. El catolito estaba separado del anolito por membranas de intercambio cationico. El catolito se hizo circular entre dos depositos de 50 1 y se dirigio hacia el catodo de mercurio sometido a una agitacion energica. El potencial del mercurio se mantuvo constante en -1,5 V comprobandolo con un electrodo patron de Ag/AgCl/KCl (sat.). El rendimiento de la corriente es aproximadamente el 90% y la energia consumida para el proceso de reduccion esde unos 0,8 kWh/kg de dioxido de uranio. Una vez terminada la electrolisis, se inicio la precipitacion calentando simplemente a 70 deg. C la solucion limpida de color verde obscuro, en otro recipiente de vidrio de 60 1 de capacidad. A partir de 50 1 de solucion de catolito se obtuvo por centrifugacion 1 kg de producto (conteniendo alrededor de un 20% de agua). El analisis por culombimetria de la razon O/U dio resultados siempre comprendidos entre 2,04 y 2,09. El procedimiento descrito permite precipitar selectivamente el oxido hidratado de uranio (IV) observandose que la razon O/U en el precipitado es independiente del grado que haya alcanzado la reduccion. Analizando el polvo por difraccion de rayos X , se pudo identificar el producto como la fase alfa del dioxido de uranio. Se estan realizando experimentos de sinterizacion y caracterizacion del dioxido de uranio obtenido de esta manera a fin de comprobar en que medida responde a las especificaciones para combustibles nucleares ceramicos. (author) [Russian] Dlya polucheniya bol'shego kolichestva materiala, neobkhodimogo dlya tekhnologicheskikh ispytanij, sdelana popytka rasshirit' masshtab protsessa. Byl skonstruirovan ehlektrolizer iz tverdogo polivinil- khlorida s rtutnym katodom okolo 2,5dm''2 i platinovymi anodami. Katodnyj rastvor otdelyalsya ot anodnogo kationoobmennymi membranami. Katodnyj rastvor tsirkuliroval mezhdu

  15. La censura previa sobre medios digitales y contenidos personales en internet: un análisis sobre la calidad de la democracia en el Ecuador a partir de la entrada en vigencia de la Ley Orgánica de Comunicación 2013-2016

    OpenAIRE

    Rosas Lanas, Diana Gabriela

    2016-01-01

    La Ley Orgánica de Comunicación (LOC) es un instrumento de regulación que modificó el panorama mediático en el Ecuador con la entrada en vigencia en el 2013 -- El presente estudio ofrece un análisis de censura previa en el Ecuador en el período 2013 – 2016, sobre los principales medios digitales y cuentas personales en internet, artículo 18 y 4 de la LOC, respectivamente -- Con base en lo anterior y a partir del análisis de caso, el estudio reconoce la fase de implementación de la política pú...

  16. Uranium: myths and realities the depleted uranium; Uranio: Mitos y realidades. El caso del uranio emprobrecido

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, G.

    2001-07-01

    Uranium is an element whose name causes worry. The uranium properties are very unknown for people. However the element plays an important roll in the Earth as responsible of numerous natural phenomena, which are vital for life evolution. An example of the low knowledge about uranium has been the Balkan syndrome. A relation between cancers and the use of depleted uranium in ammunition in the Balkan War has been pretended to be established. From the beginning, this hypothesis could have been discarded as it has been confirmed and stated in recent reports of UNEP Commissions who have studied this matter. (Author)

  17. Ideas previas sobre el reino vegetal en niños entre los 7 y 10 años de tercero de primaria de la Escuela Normal Superior Distrital María Montessori (E.N.S.D.M.M.

    Directory of Open Access Journals (Sweden)

    Daniela Gomez

    2015-12-01

    Full Text Available La presente investigación busca reconocer las ideas previas sobre el reino vegetal en niños entre los 7 y 10 años. Se eligió un grupo de 37 estudiantes de tercero de primaria perteneciente a la E.N.S.D.M.M., con los cuales se implementó un instrumento de caracterización tipo cuestionario conformado por 3 preguntas referentes al reino vegetal. A partir de las respuestas dadas por los niños, se clasificaron sus ideas previas generando categorías de estas, posterior a ello, con la referencia de las 3 fuentes de origen (sensorial, social y analógica siendo la social en la cual se basa este trabajo; se generaron dos sub-categorias (experiencia cotidiana y  experiencia académica y, en esta última  se tuvieron en cuenta los modelos explicativos de nutrición vegetal para lo cual fue necesario analizar conceptos claves como respiración, morfología, metabolismo e interacciones con el medio. Como resultado de la caracterización se determinó que las construcciones mentales sobre el reino vegetal en estos estudiantes son mediadas por la experiencia cotidiana y son frecuentemente nutridas, modificadas o adecuadas por este a pesar de lo adquirido en la escuela, además se estableció que los modelos de nutrición vegetal más comunes en las representaciones de los niños a esta edad son el edáfico y el de transmutación

  18. Nuclear Materials Management in a Recovery Facility for Unirradiated Enriched Uranium; Gestion des Matieres Nucleaires dans une Installation de Recuperation d'Uranium Enrichi Non Irradie; Administrativno-khozyajstvennyj uchet yadernykh materialov na ustanovke po regeneratsii neobluchennogo obogashchennogo urana; Administracion de Materiales Nucleares en una Planta de Recuperacion para Uranio Enriquecido No Irradiado

    Energy Technology Data Exchange (ETDEWEB)

    Jasny, G. R. [Union Carbide Corporation, Oak Ridge, TN (United States)

    1966-02-15

    poussee du personnel charge des operations. Le transfert des informations au service de comptabilite des matieres nucleaires est assure au moyen d'un systeme de fiches qui accompagnent les matieres: chaque lot est identifie par une fiche individuelle et la livraison du lot est signalee par transfert de la fiche au service de comptabilite des matieres nucleaires{sup .} La plupart des operations comptables sont executees sur des appareils electroniques de traitement de l'information; outre les dossiers et calculs necessaires pour l'etablissement des bilans matieres, on enregistre regulierement des donnees sur la retention et la concentration afin de faciliter la detection des anomalies dans les bilans entree/sortie ou dans les inventaires. L'analyse statistique est largement utilisee pour verifier les mesures et reduire au minimum le nombre d'analyses chimiques. Toutefois, l'application des statistiques n'a pas donne de bons resultats pour l'evaluation des erreurs d'inventaire. Le memoire etudie de maniere detaillee les methodes de controle des matieres indiquees plus haut et certains des problemesiqu'elles posent. (author) [Spanish] Desde hace mas de veinte anos, la planta Y-12 de la Comision de Energia Atomica, situada en Oak Ridge, Tennessee, viene tratando y recuperando diversas formas de uranio enriquecido no irradiado. El proceso de recuperacion consiste en un tren semicontinuo de operaciones unitarias: disolucion, combustion, evaporacion, extraccion, desnitrificacion e hidrofluoracion. El equipo de tratamiento y almacena - miento es de dimensiones restringidas para evitar la criticidad y tiene una capacidad combinada de varios centenares de kg de uranio enriquecido al mes. El material sometido a las operaciones de recuperacion proviene tanto de la planta como de otras instalaciones que la CEA posee en los Estados Unidos. Este material incluye practicamente todos los tipos de residuos de uranio enriquecido sin irradiar. El control fisico se ejerce satisfactoriamente

  19. Ultrasonic Inspection following Heat Treatment of Uranium Alloys; Controle des Traitements Thermiques d'Alliage d'Uranium par Ultrasons; Kontrol' termicheskoj obrabotki uranovykh splavov s pomoshch'yu ul'trazvuka; Control Ultrasonico de los Tratamientos Termicos de Aleaciones de Uranio

    Energy Technology Data Exchange (ETDEWEB)

    Destribats, Marie-Therese; Cherpentier, C.; Papezik, F.; Pigeon, M. [Centre d' Etudes Nucleaires Desaclay (France)

    1965-10-15

    necessaire. Il s'est avere indispensable de pouvoir effectuer un controle sur l'ensemble de l'element et la totalite d'une production afin de connaitre exactement la qualite du combustible utilise. Ce controle ne pouvait etre envisage par micrographie en raison de la duree trop longue des operations et de leurs resultats partiels. Le controle auquel les auteurs ont procede est base sur le principe de l'absorption des ultrasons par les materiaux. L'absorption est fonction de la structure du milieu. Si {lambda} est petit par rapport a la taille du grain G, elle est faible; si G est de l'ordre de {lambda}/2, elle est tres grande. Les tout premiers essais ont ete faits dans l'air, par echos multiples, puis en mesurant la hauteur du premier echo, ensuite par transmission dans l'eau, en comparant la hauteur de l'echo transmis a celle de l'echo initial. Dans le controle industriel, on compare l'amplitude de l'echo transmis par le materiau a l'echo obtenu avec un etalon bien traite de meme nuance et de meme forme geometrique. L'examen se fait dans une machine speciale; les materiaux sont entraines en rotation par des galets et les traducteurs orientables se deplacent le long de l'element. L'exploration helicoiedale s'effectue avec un pas inferieur a 5 mm. Le generateur d'ultrasons comporte un systeme de regulation qui maintient l'echo de reference constant. On montrera, une serie d'enregistrements obtenus sur divers alliages, en particulier des defauts observes sur les elements traites par induction au defile. Des zones mal traitees inferieures a 1 cm{sup 2} sont detectees. Actuellement, on controle ainsi tous les combustibles en uranium faiblement allies des divers reacteurs G2, EL3, EDF1, EDF2 et INCA, c'est-a-dire des barres et tubes de diametre compris entre 20 et 95 mm. (author) [Spanish] Con el fin de aumentar en los reactores la estabilidad de las aleaciones con bajo contenido de uranio resulta a menudo necessario afinar el grano mediente tratamientos termicos. Para conocer

  20. Pulsed Neutron Studies of BeO-Natural Uranium Lattices; Etudes de Reseaux Uranium Naturel-Glucine, par la Methode des Neutrons Pulses; Issledovanie reshetok BeO-prirodnyj uran s pomoshch'yu impul'snykh nejtronov; Estudio de Reticulados de Beo-Uranio Natural con Ayuda de Neutrones Pulsados

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, B. V.; Nargundkar, V. R.; Subbarao, K. [Atomic Energy Establishment Trombay, Bombay (India)

    1965-10-15

    verticalement dans des .canaux de section carree 5 x 5 cm dans un reseau carre dont le pas etait de 15 cm. Les bouffees de neutrons etaient produites par la reaction Be(d,n), la source de deuterons puises etant un accelerateur a cascade. Les detecteurs etaient des compteurs proportionnels au BF{sub 3}. Les harmoniques du lieu et du temps ont ete eliminees de la facon decrite par les auteurs dans un autre memoire presente au meme colloque. Les auteurs ont determine la constante de decroissance du mode fondamental pour plusieurs laplaciens, loin de l'etat critique. Dans ces calculs, ils ont tenu compte de l'effet de refroidissement par diffusion et de l'anisotropie. Ils ont determine toutes les constantes de diffusion et de multiplication en ajustant les donnees de trois manieres differentes par la methode des moindres carres. Ils ont obtenu le laplacien pour l'etat critique instantane en resolvant l'equation de la constante de decroissance pour {lambda} = 0. Les resultats definitifs qu'ils ont obtenus sont les suivants: Longueur de diffusion L = 15,2 cm Constante d'absorption {lambda}{sub 0} = 762, 5 s{sup -1} Coefficient de diffusion D = 1,761 * 105 cm{sup 2}/s Constante de refroidissement par diffusion C = -8,766 * 10{sup 5} cm{sup 4}/s Age {tau} = 150,7 cm{sup 2} Facteur de multiplication infini k{sub {infinity}} = 1,126 Laplacien pour l'etat critique instantane B{sup 2} = 3,00 * 10{sup -4} cm{sup -2}. (author) [Spanish] Los autores describen el empleo del metodo de los neutrones pulsados para determinar los parametros de difusion y las constantes de multiplicacion de diversos reticulados. Empleando este metodo, han obtenido los parametros de difusion y las constantes de multiplicacion en reticulados de BeO-uranio natural. Las barras de uranio empleadas medfan 2,92 cm de diametro, estaban revestidas de una capa de aluminio de 0,072 cm de espesor, y se hallaban colocadas verticalmente en canales de seccion cuadrada de 5 cm de lado, en un reticulado cuadrado de 15 cm de paso

  1. Construction, Cost and Use of an Enriched Uranium, Light-Water Subcritical Assembly; Assemblage Sous-Critique a Uranium Enrichi et Eau Legere; Realisation, Cout et Application; Realizatsiya i stoimost' podkriticheskoj sborki na obogashchennom urane i legkoj vode; Construccion, Coste y Aplicacion de un Conjunto Subcritico de Uranio Enriquecido

    Energy Technology Data Exchange (ETDEWEB)

    Vittoz, B.; Berthet, P.; Gavin, P.; Mandrin, C.; Robert, P.; Thurnheer, J. [Ecole Polytechnique de l' Universite de Lausanne (Switzerland)

    1964-02-15

    flux de neutrons. L'etude est poursuivie en etudiant l'influence de la distance entre les barres d'un meme plan. (author) [Spanish] El conjunto subcritico de la Escuela Politecnica de la Universidad de Lausana esta destinado al estudio experimental de los reticulados multiplicadores, pero se emplea tambien para fines de enseflanza. La instalacion se presta a usos multiples. Los autores exponen los motivos que indujeron al Laboratorio de Ingenieria Nuclear de la citada Escuela Politecnica a construir el conjunto subcritico, por sus propios medios en toda la medida de lo posible, y a elegir un reticulado de uranio poco enriquecido-agua ligera. Describen el principio y la construccion de los dispositivos que permiten variar comoda y rapidamente los parametros relativos al reticulado y a la alimentacion neutronica: 1. Las barras de uranio estan suspendidas verticalmente; cada punto de suspension posee dos grados de libertad sin restriccion de continuidad. Este principio permite, por ejemplo, variar de forma continua el paso del reticulado. 2. La alimentacion neutronica queda asegurada por cinco fuentes de Pu-Be colocadas sobre un pedestal de grafito. La separacion entre estas fuentes tambien se puede regular de forma continua. Los autores examinan los problemas de seguridad que plantea la instalacion, yaque la reactividad puede variar en gran medida de una configuracion a otra. Por ultimo, informan sobre el costo de la construccion y de los gastos de explotacion de este conjunto subcritico. Una de las investigaciones llevadas a cabo en el conjunto es el estudio de un reticulado aperiodico en el que se procura obtener un flujo uniforme. A este efecto se recurre a la teoria heterogenea establecida por Feinberg y Horning, considerando primero un reticulado de barras distribuidas de forma identica en n planos paralelos no equidistantes. Cada plano de barras constituye una fuente de neutrones rapidos y un absorbedor de neutrones termicos. Fuera de estos planos se utilizan las

  2. Recent Developments in the Chemical Thermodynamics of the Uranium Chalcogenides; Progres Accomplis Recemment dans la Thermodynamique Chimique des Chalcogenures d'Uranium; Poslednie dostizheniya v khimicheskoj termodinamike khal'kogenidov Urana; Recientes Progresos en la Termodinamica Quimica de los Calcogenidos de Uranio

    Energy Technology Data Exchange (ETDEWEB)

    Westrum, Jr., E. F. [University of Michigan, Ann Arbor, MI (United States)

    1966-02-15

    thermodynamiques sont en bon accord avec le systeme d'estimation de l'entropie de Gronvold et Westrum. (author) [Spanish] La extension a temperaturas mas elevadas de los datos criotermicos correspondientes al U{sub 4}O{sub 11} ha puesto de manifiesto los aspectos termoffsicos de la transicion estructural gradual (sospechada) de tipo lambda a 348 Degree-Sign K, con un correspondiente aumento de entropia igual a 1,84 cal/gfm Degree-Sign K, vinculado al desplazamiento de atomos de oxigeno intersticiales. Las mediciones, de la capacidad calorifica y de la susceptibilidad magnetica, realizadas con UO{sub 2}'Mallinckrodt' sinterizado, confirmaron que la transicion antiferromagnetica-paramagnetica tiene lugar a 30,4 Degree-Sign K con una variacion de capacidad calorifica igual a 400 cal/gfm Degree-Sign K, en lugar de producirse a 28,7eK con una variacion de 9 cal/gfm eK, segun se informa en la literatura tecnica. Con ello se puede interpretar ahora la anomalia termica hallada en el U{sub 3}O{sub 7}-{beta}. La capacidad calorifica a bajas temperaturas de muestras bien caracterizadas de UO{sub 3}-{alpha}, UO{sub 3}-{beta} y UO{sub 3} -{gamma}, preparadas por el Dr. E.H.P. Cordfunke, del Reactor Centrum Nederland, se combina con estas capacidades calorificas a temperaturas mas elevadas, con las entalpias de formacion y con otros datos termodinamicos, para obtener datos de estabilidad relativa correspondientes a esos importantes materiales nucleares. Tanto el monoseleniuro como el diseleniuro de uranio poseen anomalias de tipo lambda vinculadas al desordenamiento magnetico. La del diseleniuro de uranio se produce a 13,1 Degree-Sign K, con un incremento de entropia igual a 0,16 cal/gfm Degree-Sign K. La anomalia de 160 Degree-Sign K tiene un incremento de entropia de 1,0 cal/gfm eK, que puede compararse con el valor 1,17 encontrado para el monosulfuro cerca de los 180 Degree-Sign K. Ambas anomalias termicas observadas en los monocalcogenidos surgen como consecuencia del desordenamiento del

  3. Research with a Natural-Uranium Light-Water Subcritical Assembly; Recherches au Moyen d'un Ensemble Sous-Critique a Uranium Naturel et a Eau Ordinaire; Issledovaniya na podkriticheskoj sborke,rabotayushchej na prirodnom urane i obychnoj vode; Investigaciones con un Conjunto Subcritico de Uranio Natural y Agua Ligera

    Energy Technology Data Exchange (ETDEWEB)

    Koskinen, H. [Institute of Technical Physics, Otaniemi (Finland)

    1964-02-15

    des coordonnees spatiales. Cette particularite contribue a simplifier la forme des equations du flux et bien souvent permet de ttouver une analogie avec les systemes critiques. Par une analyse approfondie des repartitions du flux dans un tel systeme, on peut obtenir des renseignements sur la validite de-modeles speciaux de ralentissement. On peut aussi obtenir quelques eclaircissements sur des problemes comme la fission rapide par interaction et la probabilite de fuite par resonance en fonction de l'espace. L'auteur estime que l'ensemble sous-critique, ralenti par un liquide, a cause de ses utilisations multiples et de sa securite, constitue presque la seule possiblite d'etude systematique de reseaux non uniformes. On se propose d'ajouter, a cet assemblage, des elements contenant du combustible enrichi. On pourra alors passer a l'etude systematique de reseaux mixtes. De plus, la recherche avec d'autres facteurs de non- uniformite sera plus facile parce que le flux sera plus haut. Le memoire donne quelques apercus sur le programme futur. (author) [Spanish] El autor informa sobre las investigaciones realizadas con un conjunto de uranio natural y agua ligera, y presenta algunos de los temas que constituiran el objeto de un programa futuro. La mayor parte de los datos son ineditos. Una parte reviste caracter provisional debido a que estan todavia en curso los trabajos experimentales y el analisis de los resultados. Los estudios se han concentrado en dos objetivos principales: 1. Estudio experimental de la validez de los metodos de calculos que se emplearan, particularmente en casos de geometrias especiales (distribuciones no uniformes del combustible, configuracion de subconjuntos, fronteras de forma especial, etc.). En estos casos, los estudios teoricos entranan con frecuencia ciertas dificultades de convergencia, por lo que es necesario comparar sus resultados con las distribuciones de flujo medidas. 2. Estudio de las propiedades especiales de los reticulados de uranio

  4. Determination of D{sub 2}O-2% Enriched Uranium Lattice Parameters by Means of a Critical System; Determination des Parametres d'un Reseau Uranium Enrichi a 2%-Eau Lourde au Moyen d'un Ensemble Critique; Opredelenie s pomoshch'yu kriticheskoj sistemy parametrov reshetki s 2%-nym obog ashcheniem Urana i s zamedlitelem D{sub 2}O; Determinacion, Mediante un Conjunto Critico, de los Parametros de un Reticulado de D{sub 2}O y Uranio Enriquecido al 2%

    Energy Technology Data Exchange (ETDEWEB)

    Raisic, N.; Takac, S.; Markovic, H.; Bosevski, T. [Boris Kidric Institute of Nuclear Sciences, Belgrade, Yugoslavia (Serbia)

    1964-02-15

    faits par la theorie de la diffusion a deux groupes. Les mesures, pour dix configurations de reseau differentes, comportaient la determination du laplacien, du coefficient du niveau d'eau et des facteurs de desavantage pour le flux de neutrons thermiques et epither- miques a l'interieur d'une cellule. Le memoire decrit les methodes de mesure. Les auteurs utilisent ensuite les donnees experimentales pour en deduire les parametres de reseau determines par le calcul du coeur du reacteur au moyen de la formule des quatre facteurs et dans une theorie de diffusion a deux groupes. Ils comparent ces resultats avec les calculs classiques des memes parametres pour des configurations de reseau ayant fait l'objet de mesures. Ils ont constate des ecarts dans la valeur de n et de l'integrale de resonance pour {sup 238}U. En conclusion, les auteurs analysent l'utilite et l'exactitude des informations recueillies a l'aide des montages critiques en vue de l'etude et de l'exploitation d'un reacteur de recherche a uranium enrichi et eau lourde. (author) [Spanish] En la memoria se describe una serie de experimentos efectuados con objeto de determinar los parametros basicos de un reticulado de D{sub 2}O y uranio enriquecido al 2% Los elementos combustibles consistian en cilindros huecos, revestidos de aluminio, con agua pesada en el interior y en el exterior. Los experimentos se realizaron en el conjunto critico RB del Instituto de Ciencias Nucleares 'Boris Kidric' (Belgrado). La geometria sencilla de este conjunto facilita la interpretacion teorica de los resultados experimentales, asi como la comparacion directa con calculos efectuados segun la teoria de difusion de dos grupos. Entre las mediciones efectuadas para diez configuraciones diferentes de reticulado, figuraban la determinacion del laplaciano, del coeficiente de reactividad del nivel de agua y de los factores de desventaja para un flujo de neutrones termico y epitermico dentro de una celda del reactor. En la memoria se describen

  5. Uranium project DINAMIGE-BRGM; Proyecto Uranio DINAMIGE-BRGM

    Energy Technology Data Exchange (ETDEWEB)

    Pirelli, H

    1982-07-01

    This Uranium review was carried out in the frame work of Uranium prospecting programme between (DINAMIGE-BRGM) from February to June 1982. It was included radimetric cutting in sedimentaries and crystallines ground (gondwanic basin of the NE).The task was developed (1.300.000 scale) in Cunapiru, Carrillada, Vichadero, Minas de Corrales, Paso Mazangano and Yaguari zones.

  6. Uranium hexafluoride purification; Purificacao de hexafluoreto de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Eneas F. de

    1986-07-01

    Uranium hexafluoride might contain a large amount of impurities after manufacturing or handling. Three usual methods of purification of uranium hexafluoride were presented: selective sorption, sublimation, and distillation. Since uranium hexafluoride usually is contaminated with hydrogen fluoride, a theoretical study of the phase equilibrium properties was performed for the binary system UF{sub 6}-HF. A large deviation from the ideal solution behaviour was observed. A purification unity based on a constant reflux batch distillation process was developed. A procedure was established in order to design the re boiler, condenser and packed columns for the UF{sub 6}-HF mixture separation. A bench scale facility for fractional distillation of uranium hexafluoride was described. Basic operations for that facility and results extracted from several batches were discussed. (author)

  7. The uranium International trade.; El Comercio Internacional del Uranio.

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez U, L A

    1994-12-31

    The aim of this thesis is the understanding of how the present dynamic of uranium International trade is developed, the variables which fall into, the factors that are affecting and conditioning it, in order to clarify which are going to be the outlook in the future of this important resource in front of the present ecological situation and the energetic panorama of XXI Century. For this purpose, as starting point, the uranium is considered as a strategic material which importance take root in its energetic potential as alternate energy source, and for this reason in Chapter I, the general problem of raw materials, its classification and present situation in the global market is presented. In Chapter II, by means of a historical review, is explain what uranium is, how it was discovered, and how since the end of the past Century and during the last three decades of present, uranium pass of practically unknown element, to the position of a strategic raw material, which by degrees, generate an International market, owing to its utilization as a basic resource in the generation of energy. Chapter III, introduce us in the roll played by uranium, since its warlike applications until its utilization in nuclear reactors for the generation of electricity. Also is explain the reason for this change in the perception at global level. Finally, in Chapter IV we enter upon specifically in the present conditions of the International market of this mineral throughout the trends of supply and demand, the main producers, users, price dynamics, and the correlation among these economical variables and other factors of political, social and ecological nature. All of these with the purpose to found out, if there exist, a meaning of the puzzle that seems to be the uranium International trade.

  8. Geochemistry study of orientation made in the Uranio mission context

    International Nuclear Information System (INIS)

    1982-01-01

    The objective of the geochemical study or guidance study, is to select the three main parameters of strategic a geochemical prospection: place election for samples extraction, king of material to sample, the average density of sampling. Also throughout the tours, complementary studies can take place in order to improve the chosen techniques initially. Inspiring by results obtained by Alain Lambert to us by the end of 1981 in diverse tactics done in known indications, we have come to a preliminary study days 7 and 8 of January of 1982 in the South Long Hill region. During the campaign of strategic prospection, two complementary studies were realised: one in the region of Yerba Sola and another one in Paso Severino from the 6 to the 9 of October of 1982

  9. Mining inventory of Uruguay : Uranium; Inventario Minero Nacional : Uranio

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1983-07-01

    With the aim of Uruguay Uranium prospecting in this document has been summarized the following items: lithostratigraphy, background, economics aspects, radiation measuring, geochemistry, geophysics in Yerba Sola, Magnolia, Paso Amarillo, La Mercedes, Puntas de Abrojal, Las Chircas, La Divisa, Chuy, Apretado and Frayle Muerto.

  10. Reforma Tributaria en Argentina: Algunas necesarias definiciones previas

    Directory of Open Access Journals (Sweden)

    Ricardo Bara

    2015-09-01

    Full Text Available Hay aceptación general que nuestro actual “sistema” tributario tiene inconvenientes graves. Pero también hay diferencias notorias respecto cuáles son las reformas aconsejables. Para ordenar el tratamiento del tema se exponen los criterios normativos básicos en los que se apoya cualquier propuesta de un sistema tributario aconsejable, derivados de la literatura académica sobre Hacienda Pública y la experiencia práctica de otras naciones. Las relaciones fiscales son una parte de las normas, derechos y facultades de cada uno de los sectores, establecidas en el sistema institucional que define la Constitución Nacional. Los recientes avances de la economía política y de la economía institucional han producido resultados importantes para la comprensión de las interrelaciones en los sistemas económicos e institucionales y ellos son aplicables a los sistemas tributarios. El trabajo procura incorporar estos nuevos aportes para derivar los criterios normativos. Por otra parte, una reforma tributaria es un fenómeno complejo. Se trata de un cambio sobre un sistema ya existente que debe “seguir funcionando” con importantes efectos en la transición. Una reforma tributaria es un cambio institucional significativamente importante. Esto aconseja definir cuestiones como el sistema económico-político donde se va aplicar la reforma y el orden institucional que va reglar las relaciones entre el ciudadano-contribuyente y el fisco, el alcance del uso del poder, la relación entre reglas y discrecionalidad.

  11. Thermal Neutron Spectral and Spatial Distributions in Light-Water-Moderated Uranium Lattices; Distributions Spectrale et Spatiale des Neutrons Thermiques dans des Reseaux a Uranium et a Eau Leger; Spektral'noe i prostranstvennoe raspredelenie teplovykh nejtronov v uranovykh reshetkakh s vodnym zamedlitelem; Distribuciones Espectral y Espacial de los Neutrones Termicos en los Reticulados de Uranio Moderados por Agua Ligera

    Energy Technology Data Exchange (ETDEWEB)

    Hardy, J.; Volpe, J. J.; Klein, D.; Schmidt, E.; Gelbard, E. [Bettis Atomic Power Laboratory, Pittsburgh, PA (United States)

    1964-02-15

    realizados acerca del comportamiento de los neutrones termicos en los reticulados de uranio moderados por agua ligera. Los experimentos pertenecen a dos tipos principales: mediciones del grado de utilizacion termica y mediciones, por activacion, de la distribucion espacial de los neutrones termicos en un medio acuoso uniformemente envenenado. Esos experimentos se concibieron con miras a comprobar la validez de los actuales modelos teoricos, distinguiendo los efectos espectrales de los espaciales en el interior de un reactor. Se han efectuado eomparaciones con modelos teoricos que entraflan distintas aproximaciones relacionadas con la teoria del transporte y el nucleo de dispercion de los neutrones termicos. La primera serie de experimentos consistio en medir por el procedimiento de activacion los factores de desventaja termica en distintas celdas de reticulados del conjunto TRX, que constituye un reactor de uranio ligeramente enriquecido, moderado por H{sub 2}O, con barras de combustible cilindricas dispuestas en haces hexagonales. Los autores han comparado los resultados de las mediciones del grado de utilizacion termica con los datos de calculos efectuados con arreglo al metodo de Montecarlo. Utilizaron dos nucleos, el de Radkowsky y el de N elk in. El nucleo de Radkowsky constituye una aproximacion de primer orden que se viene utilizando umversalmente en el disello de los reactores. El nucleo de Nelkin, por su parte, representa una descripcion mas reciente y mas detallada del nucleo de dispersion. Dado que los indices de absorcion calculados para los neutrones termicos dependen de la eleccion del nucleo de dispersion, especialmente si el espectro del flujo neutronico no es maxwelliano, se ideo otra serie de experimentos de activacion con ayuda del conjunto TRX para verificar de un modo mas directo la utilidad del nucleo de dispersion. Los experimentos se realizaron en condiciones tales que la deformacion espectral se debia esencialmente a un envenenamiento uniforme. Las

  12. Effectiveness of disinfection with alcohol 70% (w/v of contaminated surfaces not previously cleaned Eficacia de la desinfección con alcohol al 70% (p/v de superficies contaminadas sin limpieza previa Eficácia da desinfecção com álcool 70% (p/v de superfícies contaminadas sem limpeza prévia

    Directory of Open Access Journals (Sweden)

    Maurício Uchikawa Graziano

    2013-04-01

    Full Text Available OBJECTIVE: To evaluate the disinfectant effectiveness of alcohol 70% (w/v using friction, without previous cleaning, on work surfaces, as a concurrent disinfecting procedure in Health Services. METHOD: An experimental, randomized and single-blinded laboratory study was undertaken. The samples were enamelled surfaces, intentionally contaminated with Serratia marcescens microorganisms ATCC 14756 106 CFU/mL with 10% of human saliva added, and were submitted to the procedure of disinfection WITHOUT previous cleaning. The results were compared to disinfection preceded by cleaning. RESULTS: There was a reduction of six logarithms of the initial microbial population, equal in the groups WITH and WITHOUT previous cleaning (p=0.440 and a residual microbial load ≤ 102 CFU. CONCLUSION: The research demonstrated the acceptability of the practice evaluated, bringing an important response to the area of health, in particular to Nursing, which most undertakes procedures of concurrent cleaning /disinfecting of these work surfaces. OBJETIVO: Evaluar la eficacia desinfectante de alcohol al 70% (p/v por fricción, sin limpieza previa, en las superficies de trabajo, como procedimiento de desinfección cotidiana o de rutina en Servicios de Salud. MÉTODO: Fue desarrollado un estudio experimental de laboratorio, aleatorio y uni-ciego. Las muestras fueron obtenidas de superficies esmaltadas, intencionalmente contaminadas con microorganismos Serratia marcescens ATCC 14756 106 UFC/mL acrecido con 10% de saliva humana, sometidas al procedimiento de desinfección SIN limpieza previa. Los resultados fueron comparados a la desinfección después de limpieza. RESULTADOS: Hubo una reducción de seis logaritmos de la población microbiana inicial, igualmente en los grupos COM y SIN limpieza previa (p=0,440 y una carga microbiana residual ≤ 102 UFC. CONCLUSIÓN: La investigación demostró que es aceptable la práctica evaluada ofreciendo así una importante respuesta para

  13. Gas-flow detector for uranium contamination on finned-can surface of a reactor fuel; Detecteur a courant gazeux pour deceler la contamination en uranium des nervures des gaines de combustible nucleaire; Gazopotochnyj detektor zagryazneniya uranom rebristoj poverkhnosti obolochki reaktornykh teplovydelyayushchikh ehlementov; Detector de flujo gaseoso para medir la contaminacion de uranio en la superficie de la vaina de aletas de los elementos combustibles para reactores

    Energy Technology Data Exchange (ETDEWEB)

    Miwa, H; Shiojiri, T; Maeda, Y [Kobe Kogyo Corporation, Okubo, Akashi, Hyogo (Japan)

    1962-04-15

    alpha. Avant chaque mesure, le compteur est vide au moyen d'une pompe rotative; on y admet ensuite du gaz PR (melange de 90% d'argon et de 10% de methane). En utilisant ce nouvel appareil, les auteurs ont reussi a deceler les particules alpha emises par 1 x 10{sup -5} gramme d'uranium naturel contaminant les nervures des gaines de combustible d'unreacteur du type Calder Hall; le combustible du reacteur de recherche japonais JRR-3 sera inspecte a l'aide de ce compteur. (author) [Spanish] El detector de corriente gaseosa descrito es un contador proporcional de rejilla especialmente destinado a determinar la contaminacion del uranio en la superficie de la vaina de aletas de los elementos combustibles para reactores. Con el tipo comun de contador proporcional, compuesto solamente de catodo y colector, apenas es posible descubrir las particulas a emitidas por el uranio contaminado en superficies irregulares tales como las aletas de la envoltura de un elemento combustible, debido a la falta de uniformidad del campo electrico en 'as cercanias de la superficie. Este es el motivo que indujo a los autores a construir el contador proporcional de rejilla. Este contador consta del elemento combustible, una rejilla, unos colectores y un catodo de forma cilindrica dispuestos coaxialmente. El combustible va colocado en el centro de la rejilla y se aplica una tension negativa. El espacio entre el combustible y la rejilla actua como camara colectora de iones. La rejilla esta formada por delgados alambres de tungsteno paralelos dispuestos cilindricamente en torno del elemento combustible y conectados a masa. Los colectores son 16 alambres finos de tungsteno de construccion semejante a la de la rejilla, pero cada uno de los alambres esta electricamente aislado de los restantes. Todos los colectores estan conectados entre si a traves de resistencias de 50 k{Omega} y conectados tambien a una fuente positiva de alta tension a traves de una resistencia. El espacio entre la rejilla, los

  14. Materials Control in the Fabrication of Enriched Uranium Fuels; Controle des Matieres au Cours de la Fabrication des Combustibles a Base d'Uranium Enrichi; Uchet materialov pri izgotovlenii topliva na obogashchennom urane; Control de Materiales en la Elaboracion de Combustibles de Uranio Enriquecido

    Energy Technology Data Exchange (ETDEWEB)

    Cardwell, Jr., R. G. [Oak Ridge National Laboratory, Oak Ridge, TN (United States)

    1966-02-15

    cantidades de oxido - se desarrollaron y adoptaron como normas durante el diseflo y la fabricacion de los prototipos de los elementos combustibles destinados a la puesta en marcha del reactor de ensayo de materiales (MTR), del BSR de tipo piscina, del reactor movil de potencia del ejercito, del reactor de torre de blindaje, del reactor de demostracion para la Conferencia de Ginebra, del reactor de flujo elevado para la produccion de isotopos y del reactor experimental refrigerado por gas. La experiencia adquirida sirve de base a esta memoria en la que se destacan los problemas de control de materiales y su solucion durante la fabricacion de varios tipos de componentes de combustible de uranio enriquecido. Un buen sistema de control de materiales debe perseguir los objetivos basicos siguientes: a) reducir al minimo el numero de unidades de material que haya que contabilizar, b) establecer registros distintos para cada operacion importante y relacionarlos de manera que resulte facil encontrar las diferencias, c) integrar el mayor numero posible de controles en el numero minimo de registros a fin de evitar la duplicacion y d) introducir en el sistema un numero de verificaciones suficiente para garantizar su seguridad. En todos los programas de fabricacion se logro un control eficaz estableciendo un procedimiento unitario en las siguientes etapas: a) entrada de las materias primas, b) fabricacion de componentes, c) tratamiento de los componentes y d) manipulacion de la chatarra. La reunion de los registros de control en un resumen general ayudo a confirmar las existencias, a evaluar el proceso de fabricacion y a preparar los informes administrativos. El establecimiento de metodos de muestreo y el examen de los resultados pusieron de manifiesto la necesidad de un control multiple para asegurar un contenido adecuado de combustible. Cuando el contenido de combustible en aleacion revestia importancia critica se recurrio con buenos resultados al ajuste mecanico y a la medicion de la

  15. Irradiation Behaviour of Uranium Carbide Fuels; Comportement des carbures d'uranium sous l’effet de l'irradiation; ПОВЕДЕНИЕ УРАНО-КАРБИДНОГО ТОПЛИВА ПРИ ОБЛУЧЕНИИ; Comportamiento de los combustibles de carburo de uranio frente a la irradiación

    Energy Technology Data Exchange (ETDEWEB)

    Sinizer, D. I.; Webb, B. A.; Berger, S. [Atomics International, Canoga Park, CA (United States)

    1963-08-15

    être contenu dans des gaines en acier inoxydable avec lien de Na.. Néanmoins, les données dont on dispose actuellement permettent de conclure que le combustible UC stoechiométrique ou hypostoechiométrique, dans une gaine en acier inoxydable avec lien de Na peut être efficacement utilisé dans les réacteurs de puissance refroidis au sodium. La libération des gaz de fission et la dilatation du combustible ne constituent pas des limitations pour les réacteurs refroidis au sodium tels qu'ils sont conçus actuellement. D'autres matériaux de gainage, tels que des alliages de Cb, ou des cartouches de combustible avec lien gazeux pourront être nécessaires pour les températures très élevées. (author) [Spanish] Los autores irradiaron combustibles de carburo de uranio fundidos al arco, de composición próxima a la del UC estequiométrico, en cápsulas de acero inoxidable con unión térmica de sodio o de aleación sodio-potasio (temperaturas centrales hasta 1065eC, temperaturas medias hasta 950°C), hasta alcanzar grados de combustión de 25 000 MWd/t de uranio. En los combustibles de composición estequiométrica o levemente hiperestequio- métrica, se observa que el aumento del diámetro es aproximadamente proporcional al coeficiente de consumo hasta los 25 000 MWd/t de uranio. Cuando la temperatura media en el centro alcanza a 815°C, el diámetro aumenta en menos de 3 por ciento, al exceder el grado de combustión de los 25 000 MWd/t de uranio, y disminuye en proporción al decrecer la temperatura del combustible. A una temperatura media de 540°C, la variación de volumen observada es aproximadamente igual a la que la acumulación de productos de fisión debería producir teóricamente. El desprendimiento de gases de fisión se evalúa en menos del 1 por ciento, cuando se superan los 25 000 MWd/t de uranio, a una temperatura central de 926°C. El mencionado valor se obtiene por extrapolación, partiendo de los datos experimentales obtenidos hasta los 15 000

  16. Annealing Kinetics of the Quenched-in Resistance of Alpha-Uranium; Cinétique de la suppression par recuit de la résistance que l’uranium alpha acquiert au moment de sa trempe; КИНЕТИКА ОТЖИГА ЗАКАЛЕННОГО СОПРОТИВЛЕНИЯ АЛЬФА-УРАНА; Cinetica del recocido de regeneración de la resistencia eléctrica en el uranio alfa templado

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, B. D.; Tangri, K. [Metallurgy Division, Atomic Energy Establishment, Bombay, Trombay (India)

    1963-08-15

    Results of investigations on the ''quenched-in'' residual resistivity of high-purity alpha-uranium are reported. Experiments were carried out on thin strips of alpha-uranium quenched from within the alpha- range with a high cooling rate. The decay of resistance at liquid-nitrogen and room temperatures has been measured. From the calculations of activation energies for these recovery processes, it is seen that recovery at room temperature is primarily due to annealing of lattice vacancies and vacancy- impurity complexes. Low-temperature recovery, however, could not be explained by current theories of the quenched-in defects. This behaviour can possibly be attributed to the migration of some of the impurities,which are likely to be pinned into interstitial holes during quenching. (author) [French] Les auteurs donnent les résultats de leurs recherches sur la résistivité résiduelle acquise par de l'uranium alpha très pur au moment de sa trempe. Ils ont fait les expériences sur de fines lamelles d'uranium alpha, trempé à une température ne dépassant pas celle à laquelle l'uranium alpha n'est plus stable, et refroidi très rapidement. Ils ont mesuré la décroissance de la résistance à la température de l'azote liquide et à la température ambiante. (author) [Spanish] Los autores comunican los resultados de sus investigaciones sobre la resistividad residual observada en el uranio alfa, de elevada pureza, después de un tratamiento de templado. Efectuaron sus experimentos con tiras delgadas de uranio alia, templadas en ei intervalo alia, por enfriamiento rápido. Determinaron la disminución de la resistencia a la temperatura del nitrógeno lfquido y a temperatura ambiente. Del cálculo de las energfas de activación correspondientes a estos procesos de regeneración se deduce que la regeneración a temperatura ambiente se debe en primer término al recocido de vacantes del reticulado y de complejos vacante-impureza. En cambio, la regeneración a baja

  17. Ter anemia falciforme: nota prévia sobre seu significado para a criança expresso através da brincadeira Tener anemia falciforme: nota previa sobre el significado para el niño expresado a través del juego Having sickle-cell disease: short communication on the meaning for children as expressed through games what it means for them to have the disease

    Directory of Open Access Journals (Sweden)

    Ana Augusta Maciel de Souza

    2011-03-01

    Full Text Available Nota prévia de uma pesquisa que tem como objetivo compreender o significado de ter anemia falciforme para crianças de 3 a 12 anos de idade, a partir de uma investigação qualitativa ancorada no Interacionismo Simbólico como referencial teórico, e na Teoria Fundamentada nos Dados como referencial metodológico. Os dados são coletados por meio de entrevista com as crianças, mediada por uma sessão de Brinquedo Terapêutico. A análise preliminar dos dados permitiu compreender que ter anemia falciforme é uma vivência triste para a criança, porque, além de ser permeada pela dor, ela se percebe impotente frente ao sofrimento, reconhece seus sintomas, compreende a necessidade do tratamento, considerando-o apenas paliativo; que a família é um importante suporte, e o hospital, uma referência.Nota previa de una investigación que tiene como objetivo comprender el significado de tener anemia falciforme para niños de 3 a 12 años. Investigación cualitativa anclada en el Interaccionismo Simbólico como referencia teórica y en la Teoría Fundamentada en los datos como referencia metodológica. Los datos son recolectados por medio de entrevista con los niños, mediada por una sesión de Juguete Terapéutico. El análisis preliminar de los datos permitió comprender que tener anemia falciforme es una vivencia triste para el niño, porque además de ser atravesada por el dolor, ella se percibe impotente frente al sufrimiento, reconoce los síntomas, comprende la necesidad de tratamiento, considerándolo solamente paliativo, que la familia es un importante soporte y el hospital una referencia.Advance notice of a study aimed at understanding the significance of having sickle cell anemia for children 3 to 12 years old. It is a qualitative research grounded in Symbolic Interactionism as a theoretical perspective, and in Grounded Theory as a research method. The data have been collected through interview with the children by using therapeutic play

  18. Uranium project GEO 2 attachment: cronostratigraphy aplied to Uranium research; Proyecto Uranio anexo GEO 2: cronoestratigrafia aplicada a la investigacion de Uranio

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1983-07-01

    In the article, different sources of information about Uranium stratigraphy from Uruguay have been reviewed. Some results have been presented in Upper Cambrian period and Precambrian era, specially Devonian, Carboniferous and Silurian period.

  19. Comparison of the Economic Aspects of the Treatment and Storage of Fission Products from Installations Processing Irradiated Natural Uranium; Aspects Economiques Compares du Traitement et du Stockage des Produits de Fission Issus des Usines de Traitement de l'Uranium Naturel Irradie; Sravnitel'nye ehkonomicheskie aspekty obrabotki i khraneniya produktov deleniya, poluchaemykh na zavodakh po pererabotke obluchennogo prirodnogo urana; Aspectos Economicos Comparados del Tratamiento y del Almacenamiento de los Productos de Fision que Salen de las Plantas de Tratamiento de Uranio Natural Irradiado

    Energy Technology Data Exchange (ETDEWEB)

    Thiriet, L.; Lesur, P.; Giraud, R. [Commissariat a l' Energie Atomique, Paris (France); Wanlin, J. [Societe Saint-Gobain Techniques Nouvelles, Paris (France)

    1966-02-15

    reservoirs pouvant etre construits, et on determine la taille et la cadence optimales de leur mise en service, compte tenu des caracteristiques des produits de fission a stocker et pour diverses capacites de l'usine de traitement de l'uranium naturel irradie. Ils montrent que, si le cout de stockage depend des hypotheses faites sur la duree de vie des installations, le taux d'interet, les frais d'exploitation, le choix de la politique optimale par contre (tailles et cadences de mise en service) est independant de ces hypotheses et n'est lie qu'a la loi de variation du cout des reservoirs selon leur taille. On obtient ainsi le cout optimise de stockage indefini de ces effluents. Dans une troisieme partie, les auteurs comparent a cette solution du stockage indefini d'autres politiques possibles de gestion des produits de fission: vitrification et separation du Cs et du Sr. Ils situent economiquement ces diverses alternatives et esquissent des solutions possibles a long terme. (author) [Spanish] Despues de recordar las principales practicas administrativas que suelen aplicarse a los productos de fision, los autores exponen sucintamente las caracteristicas tecnicas esenciales de las instalaciones de almacenamiento en acero inoxidable (en medio acido) utilizadas en Francia y analizan la estructura de sus costos. Muestran hasta que punto esos costos dependen de la radiactividad de las soluciones almacenadas y del calor que desprenden. En la segunda parte de la memoria se examina el costo del almacenamiento segun las dimensiones de los depositos que pueden construirse, se determinan las dimensiones optimas de estos depositos y se indica el ritmo mas conveniente para su puesta en servicio teniendo en cuenta las caracteristicas de los productos de fision que es preciso almacenar y las diversas capacidades de las plantas de tratamiento de uranio natural irradiado. Se demuestra que si bien el costo del almacenamiento depende de algunas hipotesis (duracion de la vida util de las

  20. Efficient recovery of uranium using genetically improved microalgae; Recuperacion eficaz de uranio utilizando microalgas geneticamente mejoradas

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Rodas, V.; Gonzalez Conde, E.; Garcia-Balboa, C.

    2014-07-01

    Although bioaccumulation is an enzymatic process that requires live microalgae bio sorption is based on physicochemical interactions, and it is not necessary that microalgae are alive, whereby dried microalgae biomass achieves the same results. This alternative could represent a new safe and inexpensive way to recover U. (Author)

  1. Efficient recovery of uranium using genetically improved microalgae; Recuperacion eficaz de uranio utilizando microalgas geneticamente mejoradas

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Rodas, V.; Conde Vilda, E.; Garcia-Balboa, C.

    2015-07-01

    We propose an alternative process for the efficient recovery of dissolved uranium based on genetically improved microalgae. We isolate Chlamydomonas cf. fonticola from a pond extremely contaminated by uranium (∼ 25 ppm) from ENUSA U-mine, Saelices (Salamanca, Spain). After a process of genetic improvement we obtained a strain capable to recover 115 mg of U per g of dry weight, by mean of bio-adsorption on the cell wall (mostly) and intra-cytoplasm bioaccumulation. Such a genetically improved microalgae resist extremes of acidity and pollution, but even its dead biomass is still able to recover a large amount of uranium. (Author)

  2. Contenidos de uranio de lavas recientes en el sector sur de los Andes centrales

    Directory of Open Access Journals (Sweden)

    Guerra, N.

    1984-12-01

    Full Text Available We have studied the distribution of U in modern lava -flows of the southern part from the Central Andes (16°-28° S. For a given SiO2, content of the rocks, U abundance increases from west to east in a transects to the Andean Belt, while the depth of the subduction zone increases and the thickness of the continental curst decreases. Besides, U content tends to inerease steadly with the latitude, while the thick of the continental crust and the depth of the seismic zone decreases southward. Thus, on the basis of the available data, we are in a position to suggest that the U behavior in the studied lavas depends on the alkalanity and magmatic history of each volcanic center.

    Se presenta un estudio de distribución de U en lavas modernas del sector sur de los Andes centrales (16°-28° S. Para rocas de contenidos similares en SiO2 la abundancia de U crece de oeste a este en un perfil transversal al cordón andino, mientras que aumenta la profundidad de subducción, y disminuye la potencia de la corteza continental. Además, mientras la potencia de la corteza continental y la profundidad de la zona sísmica de Benioff disminuyen hacia el sur, U tiende a aumentar con la latitud. Así, y basado en los datos disponibles, estamos en posición de sugerir que el comportamiento de U en las rocas estudiadas, depende de la alcalinidad y de la historia magmática de cada centro volcánico.

  3. Treatment of effluent containing uranium with magnetic zeolite; Tratamento de efluente contendo uranio com zeolita magnetica

    Energy Technology Data Exchange (ETDEWEB)

    Craesmeyer, Gabriel Ramos

    2013-07-01

    Within this work, a magnetic-zeolite composite was successfully synthesized using ferrous sulfate as raw material for the magnetic part of the composite, magnetite, and coal fly ash as raw material for the zeolitic phase. The synthesis of the zeolitic phase was made by alkali hydrothermal treatment and the magnetite nanoparticles were obtained through Fe{sup 2+} precipitation on alkali medium. The synthetic process was repeated many times and showed good reproducibility comparing the zeolitic nanocomposite from different batches. The final product was characterized using infrared spectroscopy, powder X-ray diffraction, X-ray fluorescence, scanning electron microscopy with coupled EDS. Specific mass, specific surface area and other physicochemical proprieties. The main crystalline phases found in the final product were magnetite, zeolites types NaP1 and hydroxysodalite, quartz and mullite, those last two remaining from the raw materials. Uranium removal capacity of the magnetic zeolite composite was tested using batch techniques. The effects of contact time and initial concentration of the adsorbate over the adsorption process were evaluated. Equilibrium time was resolved and the following kinetics and diffusion models were evaluated: pseudo-first order kinetic model, pseudo-second order kinetic model and interparticle diffusion model. A contact time of 120 min turned out to be enough to reach equilibrium of the adsorption process. The rate of adsorption followed the pseudo-second order model and the intra particle diffusion did not turn out to be a speed determinant step. Two adsorption isotherms models, the Langmuir model and the Freundlich model, were also evaluated. The Langmuir model was the best fit for the obtained experimental data. Using the best fitted adsorption isotherm and kinetic model, the theoretical maximum adsorption capacity of uranium over the composite was determined for both models. The maximum removal capacity calculated was 20.7 mg.g{sup -1} for the Langmuir isotherm and 23.4 mg.g{sup -1} for the pseudo-second order model. The experimental value attained was 23,3 mg.g{sup -1}. (author)

  4. A new process for the fractionation of uranium; Un nuevo procedimiento para el fraccionamiento de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Costas, E.; Baselga, B.; Tarin, F.

    2015-07-01

    We propose a new biological process for uranium isotopic fractionation based on Chlamydomonas cf. fonticola (microalgae) isolated from a pond extremely contaminated by uranium (. 25 ppm) from the ENUSA mine in Saelices (Salamanca, Spain) and genetically improved. The metabolic activity of this genetically improved ChlSPGI strain allows recover 115 mg of U per gram of micoralgal biomass in a short time (because this strain complete their cell cycle in . 24 hours). During this process ChlSPGI microalgae selectively captures {sup 2}35U conducting an isotopic enrichment of {sup 2}35U ({sup 2}35U δ = + 3,983%). (Author)

  5. Uranium and plutonium in marine sediments; Uranio y plutonio en sedimentos marinos

    Energy Technology Data Exchange (ETDEWEB)

    Ordonez R, E.; Almazan T, M. G. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Ruiz F, A. C., E-mail: eduardo.ordonez@inin.gob.mx [UNAM, Instituto de Ciencias del Mar y Limnologia, Unidad Academica Mazatlan, Sinaloa (MX)

    2011-11-15

    The marine sediments contain uranium concentrations that are considered normal, since the seawater contains dissolved natural uranium that is deposited in the bed sea in form of sediments by physical-chemistry and bio-genetics processes. Since the natural uranium is constituted of several isotopes, the analysis of the isotopic relationship {sup 234}U/{sup 238}U are an indicator of the oceanic activity that goes accumulating slowly leaving a historical registration of the marine events through the profile of the marine soil. But the uranium is not the only radioelement present in the marine sediments. In the most superficial strata the presence of the {sup 239+140}Pu has been detected that it is an alpha emitter and that recently it has been detected with more frequency in some coasts of the world. The Mexican coast has not been the exception to this phenomenon and in this work the presence of {sup 239-140}Pu is shown in the more superficial layers of an exploring coming from the Gulf of Tehuantepec. (Author)

  6. Mineralización de uranio en la Sierra de Velasco, La Rioja

    International Nuclear Information System (INIS)

    Morello, O.; Aparicio González, P.

    2013-01-01

    This contribution describes an uranium mineralization found in the Sierra de Velasco, La Rioja Province, Northwest of Ar¬gentina. In the study area crop out granites, pegmatites and metamorphic rocks. The host rocks of the mineralization are the La Chinchilla Granite (Carboniferous) and the La Cébila metamorphic Complex (Precambrian-Ordovician). The mine¬ralization is perigranitic and occurs disseminated, in fractures and in the contact between the granite and the metamorphic rocks. In the La Chinchilla Granite was identified a U-Nb-Ta oxide, and in the metamorphic rocks U-silicates (uranophane, uranophane-beta), U-phosphates (phurcalite and meta-autunite) and uranium oxides (pitchblende and coffinite) were found. (authors) [es

  7. Fluorimetric determination of uranium in water; Determinacion fluorimetrica de uranio en aguas

    Energy Technology Data Exchange (ETDEWEB)

    Acosta L, E. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)]. e-mail: eal@nuclear.inin.mx

    1992-02-15

    The fluorimetric method for the determination of microquantities of uranium in water is described. This method covers the determination of uranium in water in the interval from 0.2 to 50 ppm on 50 ml. of radioactive base sample. These limits can be variable if the volume of the aliquot one of the base sample is changed, as well as the volume of the used aliquot one for to the final determination of uranium. (Author)

  8. Distribution of uranium in marine sediments; Distribucion de uranio en sedimentos marinos

    Energy Technology Data Exchange (ETDEWEB)

    Ordonez R, E.; Ramirez T, J.J.; Lopez M, J.; Aspiazu, J. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico); Ruiz F, A.C. [U. Academica Mazatlan, ICML, UNAM (Mexico); Valero C, N. [CONALEP, 52000 Lerma, Estado de Mexico (Mexico)

    2008-07-01

    The marine sediments obtained by means of a sampling nucleus in the Gulf of Tehuantepec, Mexico, they have been object of crystallographic and morphological characterization. The PIXE analysis of some samples in study is shown. The normal methodology to carry out the alpha spectroscopy indicates that the sample should be dissolved, but due to the nature of the marine sediments, it thinks about the necessity to make a fractional separation of the sample components. In each stratum of the profile it separates the organic part and the mineral to recover the uranium. It was observed that in the organic phase, the uranium is in two oxidation states (IV and Vl), being necessary the radiochemical separation with a liquid/liquid column chromatographic that uses the di-2-ethyl hexyl phosphoric acid as stationary phase. The uranium compounds extracts are electrodeposited in fine layers on stainless steel disks to carry out the analysis by alpha spectroscopy. The spectroscopic analysis of the uranium indicates us that for each stratum one has a difference marked in the quotient of activities of {sup 234}U/{sup 238}U that depends on the nature of the studied fraction. These results give us a clear idea about how it is presented the effect of the uranium migration and other radioelements in the biosphere, with what we can determine which are the conditions in that these have their maximum mobility and to know their diffusion patterns in the different media studied. (Author)

  9. Spectrographic analysis of uranium-molybdenum alloys; Analisis espectrografico de aleaciones uranio-molibdeno

    Energy Technology Data Exchange (ETDEWEB)

    Roca, M

    1967-07-01

    A spectrographic method of analysis has been developed for uranium-molybdenum alloys containing up to 10 % Mo. The carrier distillation technique, with gallium oxide and graphite as carriers, is used for the semiquantitative determination of Al, Cr, Fe, Ni and Si, involving the conversion of the samples into oxides. As a consequence of the study of the influence of the molybdenum on the line intensities, it is useful to prepare only one set of standards with 0,6 % MoO{sub 3}. Total burning excitation is used for calcium, employing two sets of standards with 0,6 and 7.5 MoO{sub 3}. (Author) 5 refs.

  10. Uranium project. Geochemistry prospection[Study of Uranium geochemical prospection in Uruguay]; Proyecto Uranio. Prospeccion geoquimica

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, J

    1983-07-01

    Geochemistry studies the distribution of the chemicals elements in the terrestrial crust and its ways to migrate. The terminology used in this report is the following one: 1) Principles of the prospection geochemistry 2) Stages of the prospection geochemistry 3)utility of the prospection geochemistry 4) geochemistry of uranium 5) procedures used within the framework of uranium project 6) Average available 7) Selection of the zones of prospection geochemistry 8) Stages of the prospection, Sample preparation and analisis 9) Presentation of the results.

  11. Biossorption of uranium on banana pith; Biossorcao de uranio nas cascas de banana

    Energy Technology Data Exchange (ETDEWEB)

    Boniolo, Milena Rodrigues

    2008-07-01

    Banana pith was characterized by Fourier Transformed Infrared Spectroscopy and Scanning Electron Microscopy, and investigated as a low cost bio sorbent for the removal of uranium ions from nitric solutions. Influences variable as were studied: adsorbent particle size, contact time, pH and temperature were studied. The removal percentage was increased from 13 to 57% when the particle size was decreased from 6.000 to 0.074 mm. The determined contact time was 40 minutes with 60% mean removal. The removal was increased from 40 to 55% when the pH varied from 2 to 5. The Langmuir and Freundlich linear isotherm models were applied to describe the adsorption equilibrium. The kinetic of the process was studied using the pseudo-first order and pseudo-second order models. Thermodynamics parameters such as {delta}G, {delta}S and {delta}H were calculated. In concentration range of 50 - 500 mg.L{sup -1}, the adsorption process was described better by the Freundlich equation. The adsorption capacity at equilibrium of uranium ions was determined from the Langmuir equation, and it was found 11.50 mg.g{sup -1} at 25 {+-} 2 deg C. The kinetic was better represented by the pseudo-second order model. The bio sorption process for uranium removal from the solutions was considered an exothermic reaction, and the values of {delta}H and {delta}S obtained were -9.61 kJ.mol''-{sup 1} and 1.37 J.mol''-{sup 1}, respectively. The values of the Gibbs free energy changed from -10.03 to -10.06 kJ.mol{sup -1} when the temperature was increased from 30 to 50 deg C. This study showed the potential application of the banana pith as bio sorbent of uranium ions. (author)

  12. Biossorption of uranium on banana pith; Biossorcao de uranio nas cascas de banana

    Energy Technology Data Exchange (ETDEWEB)

    Boniolo, Milena Rodrigues

    2008-07-01

    Banana pith was characterized by Fourier Transformed Infrared Spectroscopy and Scanning Electron Microscopy, and investigated as a low cost bio sorbent for the removal of uranium ions from nitric solutions. Influences variable as were studied: adsorbent particle size, contact time, pH and temperature were studied. The removal percentage was increased from 13 to 57% when the particle size was decreased from 6.000 to 0.074 mm. The determined contact time was 40 minutes with 60% mean removal. The removal was increased from 40 to 55% when the pH varied from 2 to 5. The Langmuir and Freundlich linear isotherm models were applied to describe the adsorption equilibrium. The kinetic of the process was studied using the pseudo-first order and pseudo-second order models. Thermodynamics parameters such as {delta}G, {delta}S and {delta}H were calculated. In concentration range of 50 - 500 mg.L{sup -1}, the adsorption process was described better by the Freundlich equation. The adsorption capacity at equilibrium of uranium ions was determined from the Langmuir equation, and it was found 11.50 mg.g{sup -1} at 25 {+-} 2 deg C. The kinetic was better represented by the pseudo-second order model. The bio sorption process for uranium removal from the solutions was considered an exothermic reaction, and the values of {delta}H and {delta}S obtained were -9.61 kJ.mol''-{sup 1} and 1.37 J.mol''-{sup 1}, respectively. The values of the Gibbs free energy changed from -10.03 to -10.06 kJ.mol{sup -1} when the temperature was increased from 30 to 50 deg C. This study showed the potential application of the banana pith as bio sorbent of uranium ions. (author)

  13. Uranium dissolution from calciothermic and magnesiothermic; Disolucion de uranio en escorias de calciotermia y magnesiotermia

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigo Otero, A; Rodrigo Vilaseca, F; Morales Calvo, G; Mendez Mendez, J

    1976-07-01

    A laboratory study to recover uranium from the slags in a production process, has been undertaken. Main variables considered are concentrations of nitric acid, temperature, etc. Likewise, and according to the attack variables the slags slurries filtration has been studied. As a result, the optimum work conditions for a treatment plant, are fixed. (Author) 8 refs.

  14. Processing of Sierra Albarrana uranium ores; Tratamiento de los minerales de uranio de Sierra Albarrana

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez Jodra, L; Perez Luina, A; Perarnau, M

    1960-07-01

    Uranium recovery by hydrometallurgy from brannerite, found in Hornachuelos (Cordoba) is described. It has been studied the acid and alkaline leaching and salt roasting, proving as more satisfactory the acid leaching. Besides the uranium solubilization by acid leaching, is described the further process to obtain pure uranyl nitrate. (Author)

  15. Fluorescence uranium determination; Determinacion de uranio por fluorescencia. I. Proyecto de equipo y comprobacion

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez Cellini, R; Crus Castillo, F. de la; Barrera Pinero, R

    1960-07-01

    An equipment for analysis of uranium by fluorescence was developed in order to determine it at such a low concentration that it can not be determined by the most sensible analytical methods. this new fluorimeter was adapted to measure the fluorescence emitted by the phosphorus sodium fluoride-sodium carbonate-potasium carbonate-uranyl, being excited by ultraviolet light of 3,650 A the intensity of the light emitted was measure with a photomultiplicator RCA 5819 and the adequate electronic equipment. (Author) 19 refs.

  16. Heap leaching of clay ish uranium ores; Lixiviacion estatica de minerales arcillosos de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, E; Sedano, A

    1973-07-01

    This paper describes an experimental facility, built near El Lobo mine. In it we study the beneficiation of low-grade uranium ore. The mineral has a great amount of clay and fines. The flow-sheet used has four steps: head leaching, ph-ajustement, ion-exchange and participation. We show, also, the most interesting results. (Author)

  17. Internal dosimetric evaluation due to uranium aerosols; Evaluacion dosimetrica interna debido a aerosoles de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Juan, Garcia Aguilar; Gustavo, Delgado Avila [Instituto Nacional de Investigaciones Nucleares, Salazar (Mexico)

    1991-07-01

    The present work has like object to carry out the internal dosimetric evaluation to the occupationally exposed personnel, due to the inhalation of aerosols of natural uranium and enriched in the pilot plant of nuclear fuel production of the National Institute of Nuclear Research.

  18. Efectos de la cobertura vacunal previa en la dinamica de un brote de sarampion

    OpenAIRE

    Luna Sánchez Antonio

    1997-01-01

    FUNDAMENTO: La eficacia de una vacuna debería medirse mediante ensayos clínicos controlados, no obstante, aspectos éticos lo impiden. Orenstein sugiere que se estime la eficacia de una vacuna mediante, entre otros métodos, el estudio de los brotes epidémicos de la enfermedad caso de ser posible. El presente estudio plantea el cálculo de la eficacia vacunal en el terreno y de los efectos protectores de un programa de vacunación mediante el análisis de un brote epidémico de sarampión. MATERIAL ...

  19. Mecanismos fisiológicos implicados en la ansiedad previa a exámenes

    Directory of Open Access Journals (Sweden)

    Annia Yolanda del Toro Añel

    2014-10-01

    Full Text Available En el campo de la salud mental, llama la atención de clínicos e investigadores la situación de los estudiantes universitarios en cuanto al estrés académico, puesto que las exigencias en este sentido, particularmente la presión ante los exámenes, es reconocida por los propios jóvenes como uno de los factores más estresantes que genera estados de ansiedad en ellos y, por ende, afecta su rendimiento académico. En este artículo se destacan las interacciones entre el sistema nervioso y endocrino, así como las influencias del estrés psicológico sobre el rendimiento académico

  20. Profilaxis antimicrobiana previa a procedimientos dentales. Situación actual y nuevas perspectivas

    OpenAIRE

    Rodríguez-Campos, LF; Ceballos-Hernández, H; Bobadilla-Aguirre, A

    2017-01-01

    Resumen La bacteremia secundaria a los procedimientos dentales puede dar origen a episodios de endocarditis infecciosa. La implementación de la profilaxis antimicrobiana tiene como finalidad aminorar la bacteremia transitoria reduciendo la posibilidad de desarrollar endocarditis infecciosa, por lo que es indispensable conocer qué antibióticos son de elección y en qué casos o situaciones administrarlos u omitirlos. Existen múltiples guías para aplicar profilaxis antimicrobiana, éstas difieren ...

  1. Profilaxis antimicrobiana previa a procedimientos dentales. Situación actual y nuevas perspectivas

    Directory of Open Access Journals (Sweden)

    Luis Fernando Rodríguez-Campos

    2017-08-01

    Full Text Available La bacteremia secundaria a los procedimientos dentales puede dar origen a episodios de endocarditis infecciosa. La implementación de la profilaxis antimicrobiana tiene como finalidad aminorar la bacteremia transitoria reduciendo la posibilidad de desarrollar endocarditis infecciosa, por lo que es indispensable conocer qué antibióticos son de elección y en qué casos o situaciones administrarlos u omitirlos. Existen múltiples guías para aplicar profilaxis antimicrobiana, éstas difieren en sus recomendaciones, a tal grado que pueden confundir al facultativo al momento de determinar si el paciente requiere antibiótico profiláctico y a elegir el antimicrobiano adecuado.   OBJETIVO: comparar las diferentes guías de profilaxis antimicrobiana y recomendaciones para converger en una recopilación única con las aportaciones destacadas de cada guía revisada; de la misma manera, exponer el régimen utilizado en nuestra institución por el servicio de estomatología.   CONCLUSIÓN: el estomatólogo se puede basar principalmente en las guías de la American Heart Association (AHA y el Centro Nacional de Excelencia Tecnológica en Salud (CENETEC para condiciones cardiacas que ameriten profilaxis antimicrobiana, y para pacientes con enfermedades sistémicas sobre la guía de la American Academy of Pediatric Dentistry (AAPD y las recomendaciones de nuestra institución. La administración de profilaxis antimicrobiana se da por razones científicas consolidadas y por carácter de tipo médico-legal, en un futuro se espera establecer criterios para aumentar los métodos no antibióticos preventivos de endocarditis infecciosa y aminorar el uso de antimicrobianos, reduciendo el uso de antibiótico profiláctico, sin exponer al paciente a infecciones diseminadas y con mínimos efectos secundarios posibles.

  2. Profilaxis antimicrobiana previa a procedimientos dentales. Situación actual y nuevas perspectivas

    OpenAIRE

    Luis Fernando Rodríguez-Campos; Hilda Ceballos-Hernández; Alfredo Bobadilla-Aguirre

    2017-01-01

    La bacteremia secundaria a los procedimientos dentales puede dar origen a episodios de endocarditis infecciosa. La implementación de la profilaxis antimicrobiana tiene como finalidad aminorar la bacteremia transitoria reduciendo la posibilidad de desarrollar endocarditis infecciosa, por lo que es indispensable conocer qué antibióticos son de elección y en qué casos o situaciones administrarlos u omitirlos. Existen múltiples guías para aplicar profilaxis antimicrobiana, éstas difieren en sus r...

  3. Efectos de la cobertura vacunal previa en la dinamica de un brote de sarampion

    Directory of Open Access Journals (Sweden)

    Luna Sánchez Antonio

    1997-01-01

    Full Text Available FUNDAMENTO: La eficacia de una vacuna debería medirse mediante ensayos clínicos controlados, no obstante, aspectos éticos lo impiden. Orenstein sugiere que se estime la eficacia de una vacuna mediante, entre otros métodos, el estudio de los brotes epidémicos de la enfermedad caso de ser posible. El presente estudio plantea el cálculo de la eficacia vacunal en el terreno y de los efectos protectores de un programa de vacunación mediante el análisis de un brote epidémico de sarampión. MATERIAL Y MÉTODOS: Estudio de cohortes retrospectivo. La población de estudio la constituyó el grupo de niños nacidos en el municipio de Aznalcollar (localidad de 5.571 habitantes perteneciente al Distrito Sanitario Aljarafe-Sevilla entre dos brotes epidémicos de sarampión ocurridos en dicha localidad en los años 1986 y 1994. Se excluyeron de la cohorte a aquellos niños que a comienzos del brote de 1994 no habían cumplido la edad de vacunación y también a quienes tuvieron exposición anterior al virus, es decir los nacidos antes y durante la epidemia de 1986. El estudio incluyó a vacunados y no vacunados. Todos los casos cumplían los criterios diagnósticos establecidos. A todos los niños en seguimiento se les revisó sus antecedentes vacunales. Tras el cálculo de las tasas de ataque en vacunados y no vacunados, se determinaron la eficacia vacunal y los efectos indirectos totales y medios del programa de vacunación. RESULTADOS: La vacuna resultó eficaz en el 91'5 % de los vacunados. El programa de vacunación produjo una reducción del número de casos en los no vacunados del 78'9%, del 98% en los vacunados y del 92% en el conjunto de la cohorte estudiada, siendo la cobertura vacunal de la misma del 66'4%. CONCLUSIONES: Los efectos de la vacunación y la eficacia vacunal pueden y deben ser calculados aprovechando la aparición de brotes epidémicos caso de ser posible. Se recomienda incrementar las coberturas de vacunación de la población y mejorar así los efectos protectores del programa.

  4. Hidroxiapatita en defectos óseos craneales: Comunicación previa

    Directory of Open Access Journals (Sweden)

    Susana A Fernández Benítez

    1997-12-01

    Full Text Available Se exponen los resultados iniciales de un ensayo experimental y clínico, con gránulos de hidroxiapatita como implante en defectos óseos craneales aun radiológicos y microscópicos (BAAF el tiempo de los pasos de osificación craneal. Hubo crecimiento de fibroblasto en 7 días; en 2 meses y medio, crecimiento de osteoblastos y de hueso intramembranoso. En 3 meses la plastia presentaba consistencia ósea palpableThe initial results of an experimental and clinical assay using hydroxyapatite granules as implants in skull defects over 3 cm are exposed. An attempt is made to verify by clinical, radiological and microscopic examinations (BAAF the time of the cranial ossification steps. It was observed a growth of fibroblasts in 7 days, and of osteoblasts and intramembranous bone in 2 months and a half. 3 months later the plastic presented a palpable osteal consistency

  5. Embarazo deseado y planificado, lactancia previa, aptitud para lactar y conocimientos de las madres sobre lactancia

    Directory of Open Access Journals (Sweden)

    Remigio Rafael Gorrita Pérez

    Full Text Available Introducción: la OMS y la Unicef recomiendan lactancia materna exclusiva durante los primeros 6 meses de vida, y complementada, al menos, hasta los 2 años; sin embargo, los resultados no son los esperados. Objetivo: evaluar la relación entre la planificación del embarazo, la lactancia en hijos anteriores, la aptitud referida para lactar y los conocimientos sobre lactancia materna de las gestantes en su tercer trimestre, de los Policlínicos "Luis Augusto Turcios Lima" y "Mártires del 9 de Abril", del municipio San José de las Lajas. Métodos: se realizó un estudio analítico y transversal, entre marzo de 2010 y marzo de 2011. De 192 gestantes en su tercer trimestre, y que cumplieron los criterios de inclusión, se estudiaron: hijos previos y si recibieron lactancia materna, planificación, deseos del embarazo, aptitudes referidas, así como conocimientos sobre la lactancia. Se aplicaron 22 preguntas y se estableció un sistema de puntaje. Resultados: algo más de la mitad de las madres se consideraron aptas para la lactancia, y asumieron que poseían los conocimientos necesarios para lograrlo, pero menos de la quinta parte mostró poseerlos. Las gestantes que obtuvieron valores superiores en el cuestionario fueron: las que tenían un hijo previo, las que ya habían ofrecido lactancia materna exclusiva de 4 a 6 meses, y las que deseaban y habían planificado su embarazo. Conclusiones: aunque la mayoría de las gestantes consideraron que estaban aptas para la lactancia materna, no demostraron tener los conocimientos necesarios para asumirla exitosamente.

  6. Optimización y validación metodológica de la cuantificación de arsénico por inyección en flujo-generación de hidruros- espectrometría de absorción atómicas (IF-GH-EAA previa derivatizacíon con L-Cisteína Optimización and validation method for arsenic quantification by flow injection-hydride generation - atomic absorption spectrometry (fi-hg-aas after L-Cysteine derivatization

    Directory of Open Access Journals (Sweden)

    Julio A Navoni

    2009-12-01

    Full Text Available El arsénico (As es un contaminante natural que afecta una amplia zona de Argentina. El nivel de As en agua de consumo es utilizado para evaluar la fuente de exposición y en orina para evaluar exposición a este tóxico. El presente trabajo tuvo como objetivo la optimización y validación metodológica de una técnica para la cuantificación de As [As suma = As inorgánico (AsI + especies metiladas: ácido monometilarsónico (MMA y ácido dimetilarsínico (DMA], producto del metabolismo del AsI, por inyección en flujo- generación de hidruros- espectrometría de absorción atómica (IF-GH-EAA, previa derivatización con L-cisteína. La recuperación de las especies estudiadas: AsI (AsIII y AsV, MMA y DMA fue cercana al 100% en todos los casos. Los límites de detección y cuantificación encontrados fueron para agua y orina: 2 y 3 μg/L; 5 y 8 μg/L respectivamente y el rango dinámico de trabajo establecido fue desde 5 a 75 μg/L, permitiendo cuantificar As en muestras de agua cercanos a los estándares internacionales vigentes para valores máximos de As en agua de consumo y en orina en niveles comparables con los establecidos en población laboralmente no expuesta. Esta propuesta metodológica es una alternativa para evaluar la exposición al As en muestras de agua y orina, sin necesidad de utilizar prolongados pre-tratamientos de muestra, de forma más rápida y económica.Arsenic (As is a natural contaminant that affects a large area of Argentina. Quantification of As in drinking water has been used to evaluate the source of exposure and As in urine to assess exposure to this toxic. This study aimed to optimize and validate a methodological technique for the quantification of As [As sum = inorganic As (AsI + methylated species: monometilarsonic acid (MMA and dimetilarsinic acid (DMA], product of AsI metabolism by flow injectionhydride generation-atomic absorption spectrometry (FI-GH-AAS, after derivatization with L-cysteine. The recovery

  7. Geochemistry study of orientation made in the Uranio mission context[Geochemical prospection of Uranium in Uruguay]; Estudios geoquimicos de orientacion realizados en el marco de la mision Uranio

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1982-07-01

    The objective of the geochemical study or guidance study, is to select the three main parameters of strategic a geochemical prospection: place election for samples extraction, king of material to sample, the average density of sampling. Also throughout the tours, complementary studies can take place in order to improve the chosen techniques initially. Inspiring by results obtained by Alain Lambert to us by the end of 1981 in diverse tactics done in known indications, we have come to a preliminary study days 7 and 8 of January of 1982 in the South Long Hill region. During the campaign of strategic prospection, two complementary studies were realised: one in the region of Yerba Sola and another one in Paso Severino from the 6 to the 9 of October of 1982.

  8. Dry uranium tetrafluoride process preparation using the uranium hexafluoride reconversion process effluents; Processo alternativo para obtencao de tetrafluoreto de uranio a partir de efluentes fluoretados da etapa de reconversao de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Silva Neto, Joao Batista da

    2008-07-01

    It is a well known fact that the use of uranium tetrafluoride allows flexibility in the production of uranium suicide and uranium oxide fuel. To its obtention there are two conventional routes, the one which reduces uranium from the UF{sub 6} hydrolysis solution with stannous chloride, and the hydro fluorination of a solid uranium dioxide. In this work we are introducing a third and a dry way route, mainly utilized to the recovery of uranium from the liquid effluents generated in the uranium hexafluoride reconversion process, at IPEN/CNEN-SP. Working in the liquid phase, this route comprises the recuperation of ammonium fluoride by NH{sub 4}HF{sub 2} precipitation. Working with the solid residues, the crystallized bifluoride is added to the solid UO{sub 2}, which comes from the U mini plates recovery, also to its conversion in a solid state reaction, to obtain UF{sub 4}. That returns to the process of metallic uranium production unity to the U{sub 3}Si{sub 2} obtention. This fuel is considered in IPEN CNEN/SP as the high density fuel phase for IEA-R1m reactor, which will replace the former low density U{sub 3}Si{sub 2}-Al fuel. (author)

  9. Thermogravimetric control of intermediate compounds in uranium metallurgy; Control termogravimetrico de productos intermedios de la metalurgia del uranio

    Energy Technology Data Exchange (ETDEWEB)

    Gasco Sanchez, L; Fernandez Cellini, R

    1959-07-01

    The thermal decomposition of some intermediate compounds in the metallurgy of the uranium as uranium peroxide, ammonium uranate, uranium and ammonium penta-fluoride, uranium tetrafluoride and uranous oxide has been study by means of the Chevenard's thermo balance. Some data on pyrolysis of synthetic mixtures of intermediate compounds which may occasionally appear during the industrial process, are given. Thermogravimetric methods of control are suggested, usable in interesting products in the uranium metallurgy. (Author) 20 refs.

  10. Sedimentary rocks Uranium in Cerro Largo Province; Uranio en rocas sedimentarias en el departamento de Cerro Largo

    Energy Technology Data Exchange (ETDEWEB)

    Scaron, P; Garau Tous, M

    1976-07-01

    With the aim of the uranium minerals exploration has been carried out several studies by UTE technicians in Cerro Largo Province from 1968 to 1969. In uranium concentration has been found pyrite, phosphate, iron oxides and manganese in uranium. Furthermore in La Divisa Ore were studied concentration Uranium enrichment has been studied in La Divisa ore.

  11. Uranium deposits obtention for fission chambers; Obtencion de depositos de uranio para fabricacion de camaras de fision

    Energy Technology Data Exchange (ETDEWEB)

    Artacho Saviron, E

    1972-07-01

    The obtention of uranium deposits of the required quality for small cylindrical fission chambers presents some difficulties. With the method of electroplating here described the uniformity, reproducibility and adherence of the obtained deposits were satisfactory. (Author) 6 refs.

  12. Preparation, characterization and certification of uranium isotope reference materials; Preparacao, Caracterizacao e certificacao de materiais de referencia isotopicos de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira Junior, Olivio Pereira de

    2006-07-01

    This work describes the preparation, characterization and certification of a set of uranium isotope reference materials ranging from 0.5 to 20.0 % of {sup 235}U in mass. The most important concepts of metrology in chemical measurements were applied so that the certified quantities in these materials could be directly traceable to the International System of Units (SI). As a consequence of this approach, these materials can be used in the instruments calibration, estimation of measurement uncertainty, method validation, assessment of performance of analysts, quality control routines and interlaboratory comparison programmes. The most advanced methods and techniques in mass spectrometry, that is, gas source mass spectrometry (GSMS), thermal ionisation mass spectrometry (TIMS) and inductively coupled plasma mass spectrometry (ICPMS) were investigated to identify which are the dominant components in the uncertainty and to quantify its contribution to the final value of the measurement uncertainty of the isotopic ratio. The results obtained were then compared to verify which are the methods and techniques associated to the lowest measurement uncertainty values. The isotope amount ratio n({sup 235}U)/n({sup 238}U) was certified in the materials produced to expanded uncertainties ranging from 0.02 to 0.10 % and the ratios n({sup 234}U)/n({sup 238}U) and n({sup 236}U)/n({sup 238}U), to uncertainties ranging from 0.03 to 2.20 %. These values fully comply to the requirements of the isotopic characterization of nuclear fuel as well as the analysis of environmental samples for nuclear safeguards. (author)

  13. Contribution to the study of gaseous Carburization of Uranium; Contribucion al estudio de la Carburacion gaesosa del uranio

    Energy Technology Data Exchange (ETDEWEB)

    Esteban Hernandez, J A; Jimenez Moreno, J M; Villota Ruiz, P de

    1966-07-01

    Thermal decomposition of uranium hydride powder obtained by hydrogenation of uranium turnings is studied on the first part of this paper. Carburization of the uranium hydride or metallic uranium powder with methane is studied in the second part. A method of uranium monocarbide fabrication under static atmosphere is described. On this method hydrogen is removed by means of an uranium getter. (Author) 6 refs.

  14. Fluorimetric determination of uranium in zirconium and zircaloy alloys; Determinacion fluorimetrica de uranio en aleaciones de zirconio y zircaloy

    Energy Technology Data Exchange (ETDEWEB)

    Acosta L, E [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    1991-05-15

    The objective of this procedure is to determine microquantities of uranium in zirconium and zircaloy alloys. The report also covers the determination of uranium in zirconium alloys and zircaloy in the range from 0.25 to 20 ppm on 1 g of base sample of radioactive material. These limit its can be variable if the size of the used aliquot one is changed for the final determination of uranium. (Author)

  15. Uranium project in Cerro Largo south orientation[Geochemical prospection of Uranium in Uruguay]; Proyecto uranio: orientacion Cerro Largo Sur

    Energy Technology Data Exchange (ETDEWEB)

    Pradier, B

    1982-07-01

    This study of orientation was realized with the purpose of recognizing the extension of the anomalies from a known source , and of being able to determine the choice of the places and the quality of the material to sampling to obtain an ideal response. We have chosen the introduction of this study in a place that offers a source in power of Uranium located accurately and that presents a sequence pedology that group the main types of soils.

  16. Marine mollusks as bio concentrators of uranium and plutonium; Moluscos marinos como bioconcentradores de uranio y plutonio

    Energy Technology Data Exchange (ETDEWEB)

    Ordonez R, E.; Almazan T, M. G.; Escalante G, D. C., E-mail: eduardo.ordonez@inin.gob.mx [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2017-09-15

    The sudden presence of certain radionuclides in the marine environment has been of global concern and has raised concerns about the nature and abundance of these, in an attempt to establish dispersion patterns from their discharge points. In the particular case of our country, there are few data on the presence and concentration of alpha emitters, such as uranium and plutonium in the littorals and due to this fact there is a need to establish their reference levels in some specific points of the Mexican littoral. This work thus raises the study of part of the biota that grows and develops in sites near the sampling points. Is known that bivalve mollusks are natural bio-concentrators due to their capacity to absorb some metals dissolved in water, being able to find contaminating metals in their soft bodies, but they also accumulate large quantities when they generate their shells from dissolved carbonates that are complex with uranium and plutonium. The shells of the mollusks were studied to determine the physicochemical characteristics of their shells and the U and Pu were also separated by means of radiochemical techniques, being then electrodeposited in steel discs and evaluated by means of alpha spectroscopy. The results of the methodology prototype are presented to determine the U and Pu dispersed in the littoral by means of the analysis of some mollusks of the zone. (Author)

  17. Uranium potentiometer determination in inactive atmosphere with ferric sulfate; Determinacion poteniometrica de uranio en atmosfera inerte con sulfato ferrico

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez Cellini, R; Alonso Lopez, J

    1956-07-01

    Potentiometric titration of Uranium with (SO{sub 4}){sub 3} Fe{sub 2}, using Cd as reducing agent has been studied; acidity and sensibility of this reaction are fixed. This method yields good results for uranite group, removing previously phosphate by ion exchange with Amberlite IR-120. (Author)

  18. Radiation hazard surveillance in spanish uranium mines; Control de los peligros de la radiactividad en las minas de uranio espanolas

    Energy Technology Data Exchange (ETDEWEB)

    Iranzo, E; Liarte, J

    1963-07-01

    The regulations applied in the uranium mines which belong to the Junta de Energia Nuclear to control the radioactive hazards, and to get the personal protection avoiding overexposures in the external radiation and inhalation of radioactive dust and gases are given. The Radon daughters concentration in the atmosphere of Avery one of the mines and the external radiation exposure and uranium excretion in urine of the miners during 1962 are specified. (Author) 9 refs.

  19. Determination of carbon in uranium and its compounds; Determinacion de carbono en uranio metal y sus compuestos

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Garcia, M M

    1972-07-01

    This paper collects the analytical methods used our laboratories for the determination of carbon in uranium metal, uranate salts and the oxides, fluorides and carbides of uranium. The carbon is usually burned off in a induction or resistance oven under oxygen flow. The CO{sub 2} is collected in barite solution. Where it is backtitrated with potassium biphthalate. (Author)

  20. Program of Environmental monitoring in uranium and thorium mines; Programa de monitoreo ambiental en minereas de uranio y torio

    Energy Technology Data Exchange (ETDEWEB)

    Perreira, E G [Centro de Desenvolvimento da Tecnologia Nuclear, Divisao de Engenharia Ambiental, Belo Horizonte, MG (Brazil)

    1991-07-01

    This work suggests a plan for the elaboration of a program of environmental monitoring of radioactive pollutants around mining of uranium and thorium with the purpose of protecting the man and the environment.

  1. Thermogravimetric control of intermediate compounds in uranium metallurgy; Control termogravimetrico de productos intermedios de la metalurgia del uranio

    Energy Technology Data Exchange (ETDEWEB)

    Gasco Sanchez, L.; Fernandez Cellini, R.

    1959-07-01

    The thermal decomposition of some intermediate compounds in the metallurgy of the uranium as uranium peroxide, ammonium uranate, uranium and ammonium penta-fluoride, uranium tetrafluoride and uranous oxide has been study by means of the Chevenard's thermo balance. Some data on pyrolysis of synthetic mixtures of intermediate compounds which may occasionally appear during the industrial process, are given. Thermogravimetric methods of control are suggested, usable in interesting products in the uranium metallurgy. (Author) 20 refs.

  2. Chemical vapor deposition (CVD) of uranium for alpha spectrometry; Deposicion quimica de vapor (CVD) de uranio para espectrometria alfa

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez V, M. L.; Rios M, C.; Ramirez O, J.; Davila R, J. I.; Mireles G, F., E-mail: luisalawliet@gmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)

    2015-09-15

    The uranium determination through radiometric techniques as alpha spectrometry requires for its proper analysis, preparation methods of the source to analyze and procedures for the deposit of this on a surface or substrate. Given the characteristics of alpha particles (small penetration distance and great loss of energy during their journey or its interaction with the matter), is important to ensure that the prepared sources are thin, to avoid problems of self-absorption. The routine methods used for this are the cathodic electro deposition and the direct evaporation, among others. In this paper the use of technique of chemical vapor deposition (CVD) for the preparation of uranium sources is investigated; because by this, is possible to obtain thin films (much thinner than those resulting from electro deposition or evaporation) on a substrate and comprises reacting a precursor with a gas, which in turn serves as a carrier of the reaction products to achieve deposition. Preliminary results of the chemical vapor deposition of uranium are presented, synthesizing and using as precursor molecule the uranyl acetylacetonate, using oxygen as carrier gas for the deposition reaction on a glass substrate. The uranium films obtained were found suitable for alpha spectrometry. The variables taken into account were the precursor sublimation temperatures and deposition temperature, the reaction time and the type and flow of carrier gas. Of the investigated conditions, two depositions with encouraging results that can serve as reference for further work to improve the technique presented here were selected. Alpha spectra obtained for these depositions and the characterization of the representative samples by scanning electron microscopy and X-ray diffraction are also presented. (Author)

  3. Separation of uranium in bone rest for their dating; Separacion de uranio en restos oseos para la datacion de estos

    Energy Technology Data Exchange (ETDEWEB)

    Garcia R, G.; Ordonez R, E.; Tenorio, D.; Cordoba, L. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, Mexico D.F. (Mexico)

    2001-07-01

    The uranium (U) and thorium (Th) recovery, as fundamental part of the 'uranium serie' technique is an alternative method for dating of bone rests in Mexico. That so is how it has been possible its application for dating geological material and in this research it has been determined the age of some mammoth samples from the basin of Mexico valley. (Author)

  4. Spectrographic determination of impurities in enriched uranium solutions; Determinacion espectrografica de impurezas en soluciones de uranio enriquecido

    Energy Technology Data Exchange (ETDEWEB)

    Capdevila, C; Roca, M

    1980-07-01

    A spectrographic procedure for the determination of trace amounts of Al, B, Ba, Be, Bi, Ca, Cd, Co, Cr, Cu, Fe, K, L i , Hg, Mn, Mo, Na, Nb, Ni, P, Pb, Ru, Sb, Sn, Sr, Ti, V, Zn, and Zr in enriched uranyl nitrate solutions from the reprocessing of spent nuclear fuels is described. After removal of uranium by either TBP or TNOA solvent extraction, the aqueous phase Is analysed by the graphite spark technique. TBP is adequate for all impurities, excepting boron and phosphorus; both of these elements can sat is factory be determined by using TNOA after the addition of mannitol to avoid boron losses. (Author) 4 refs.

  5. Derechos colectivos y consulta previa: territorio cucapá y recursos pesqueros en Baja California, México

    Directory of Open Access Journals (Sweden)

    Alejandra Navarro Smith

    2014-07-01

    Full Text Available Las demandas de reconocimiento de derechos territoriales y de uso de los recursos naturales que los pescadores cucapás le hacen al Estado mexicano, desde 1993, después de la creación de la Reserva del Alto Golfo de California y Delta del Río Colorado (en adelante, la Reserva, son unas más en el panorama de los problemas socioambientales y de despojo territorial, que afectan a los pueblos originarios en México. La característica particular en este caso es que el Estado mismo es quien construye los marcos legales en materia de protección a las especies —sin consultar debidamente a dichos pueblos—, volviendo ilegal la presencia cucapá en esa zona y vulnerando sus derechos como población indígena del delta. En consecuencia, las autoridades medioambientales y de pesca mexicanas han constituido la zona del delta del río Colorado como un territorio en disputa, al implementar esquemas de protección ambiental y de pesca, sustentados en modelos disciplinarios, que únicamente se alimentan de información biológica y pesquera. El conflicto se genera cuando se deja al elemento humano fuera de los análisis, como si las comunidades asentadas en los territorios protegidos y usuarias de los recursos no formaran parte de los ecosistemas. Al crear el núcleo de la Reserva en el mismo lugar donde se encontraban los campamentos de pesca del pueblo cucapá se volvió ilegal el aprovechamiento de los recursos pesqueros en la zona. En este contexto se han criminalizado las acciones de resistencia con las que los cucapás responden ante la regulación medioambiental del delta del río Colorado. Al ver imposibilitada la continuidad de su práctica pesquera, los habitantes se organizan para defender su acceso al territorio y, en un sentido más amplio, sus formas de vida y de trabajo. Este caso, en particular, visibiliza maneras contemporáneas por las que el Estado despoja el territorio y desaparece prácticas culturales propias de los pueblos naturales, a través de ciertos discursos y prácticas legales —en este caso los de conservación—.

  6. Ideas previas en el aprendizaje del efecto invernadero y el calentamiento global en estudiantes universitarios de ciencias exactas y naturales

    OpenAIRE

    Gulizia, Carla; Zazulie, Natalia

    2012-01-01

    El calentamiento global es un tema presente en la mayoría de los cursos iniciales de Ciencias de la Atmósfera y representa una problemática a nivel social que es ampliamente discutida tanto por científicos expertos, tomadores de decisiones, comunidades educativas y de protección ambiental. Es por esto que adquiere real importancia que este tema sea correctamente entendido por los estudiantes de niveles medio y superior que podrían eventualmente cumplir diversos roles en la sociedad. En este t...

  7. La erosión de las certezas previas: significados, percepciones e impactos del desempleo en la experiencia argentina

    Directory of Open Access Journals (Sweden)

    María Cristina Bayón

    2003-06-01

    Full Text Available In Argentina, the disruptive effects of unemployment acquire particularly serious dimensions because of the context of disintegration of what was previously a relatively well established social and employment structure.This article examines the experience, meanings and perceptions of work and unemployment, with particular emphasis on their dynamic and heterogeneous nature. The article offers a critical review of the literature on unemployment and an analysis of the major transformations of the employment market from the 1980s on, before proceeding to demonstrate, through in–depth interviews, the concrete repercussions of these processes on “ordinary people”. It thus aims to provide an appreciation of unemployment from a broad perspective, and contribute to a reformulation of welfare politics with a comprehensive, overall vision.

  8. Ranges of Iodine and Bromine Isotopes Produced in the Interaction of High-Energy Protons with Uranium; Isotopes de l'Iode et du Brome Produits par l'Interaction de Protons de Haute Energie avec l'Uranium; 041f 0420 041e 0411 0415 0413 0418 0418 0417 041e 0422 041e 041f 041e 0412 0419 041e 0414 0410 0418 0411 0420 041e 041c 0410 , 041f 041e 041b 0423 0427 0415 041d 041d 042b 0425 041f 0420 0418 0412 0417 0410 0418 041c 041e 0414 0415 0419 0421 0422 0412 0418 0418 041f 0420 041e - 0422 041e 041d 041e 0412 0411 041e 041b 042c 0428 041e 0419 042d 041d 0415 0420 0413 0418 0418 0421 0423 0420 0410 041d 041e 041c ; Alcance de los Isotopos del Yodo y del Bromo Producidos en la Interaccion de Protones de Alta Energia con el Uranio

    Energy Technology Data Exchange (ETDEWEB)

    Brandt, R. [CERN, Geneva (Switzerland); Max Planck Institut fuer Kernphysik, Heidelberg, Federal Republic of Germany (Germany)

    1965-07-15

    fission. L'auteur examine ces resulta es compte tenu des modeles de ' spallation 'et de ' fragmentation ' et donne de nouvelles definitions de ces deux termes. (author) [Spanish] En los dos aceleradores del CERN se llevan a cabo experimentos de tipo tradicional sobre determinacion del alcance de protones de 0,55 GeV y de 18, 2 GeV, utilizando una gruesa lamina de uranio juntamente con captadores de aluminio y contadores. En el separador de radioisotopos del mismo centro se procede a la separacion, previo aislamiento por procedimientos quimicos, del yodo (o del bromo). Esta operacion proporciona muestras Ubres de portador que en esencia se componen de un solo radioisotopo puro. Tambien se determina el rendimiento quimico. El analisis de los datos proporciona directamente el alcance de cada isotopo en el uranio. Para una energia protonica de 0,55 GeV, todos los isotopos del yodo tienen el mismo alcance, es decir, que todos ellos se producen en un proceso de fision. Se sabia ya que loe isotopos del yodo ricos en neutrones tienen aproximadamente el mismo alcance - tanto si la energia de los protones es superior a 1 GeV o inferior a este valor - y que el alcance de los isotopos de ese mismo elemento deficientes en neutrones disminuye a la mitad aproximadamente, cuando la energia de los protones supera 1 GeV. El autor pone de manifiesto que esta disminucion del alcance se produce de una manera bastante brusca, proporcionando una funcion escalonada para la curva del alcance en funcion de la masa isotopica del yodo. Los isotopos deficientes en neutrones cuyo alcance disminuye para una energia de los protones superior a 1 GeV son los mismos para los que se ha observado un fuerte aumento de su funcion de excitacion por encima de 1 GeV. De forma analoga, se comportan, en cuanto al alcance, los isotopos del bromo. La curva de rendimiento isotopico del bromo procedente del uranio presenta las mismas caracteristicas principales que la curva correspondiente al yodo. El fuerte aumento en

  9. Determination of uranium fission products interference factors in neutron activation analysis; Determinacao de fatores de interferencia de produtos de fissao de uranio na analise por ativacao neutronica

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro Junior, Ibere Souza

    2014-09-01

    Neutron activation analysis is a method used in the determination of several elements in different kinds of matrices. However, when the sample contains high U levels the problem of {sup 235}U fission interference occurs. A way to solve this problem is to perform the correction using the interference factor due to U fission for the radionuclides used on elemental analysis. In this study was determined the interference factor due to U fission for the radioisotopes {sup 141}Ce, {sup 143}Ce, {sup 140}La, {sup 99}Mo, {sup 147}Nd, {sup 153}Sm and {sup 95}Zr in the research nuclear reactor IEA-R1 on IPEN-CNEN/SP. These interference factors were determined experimentally, by irradiation of synthetic standards for 8 hours in a selected position in the reactor, and theoretically, determining the epithermal to neutron fluxes ratio in the same position where synthetic standards were irradiated and using reported nuclear parameters on the literature. The obtained interference factors were compared with values reported by other works. To evaluate the reliability of these factors they were applied in the analysis of studied elements in the certified reference materials NIST 8704 Buffalo River Sediment, IRMM BCR- 667 Estuarine Sediment e IAEA-SL-1 Lake Sediment. (author)

  10. Isotopic characterization of uranium in soils of the Ipanema National Forest (FLONA-Ipanema); Caracterizacao isotopica de uranio em solos da Floresta Nacional de Ipanema (FLONA-Ipanema)

    Energy Technology Data Exchange (ETDEWEB)

    Silva, F.B.; Marques, F.H., E-mail: fernandobaliani@yahoo.com.br, E-mail: fernando_henrique06@hotmail.com [Laboratorio de Pocos de Caldas (LAPOC/CNEN-MG), Pocos de Caldas, MG (Brazil); Enzweiler, J.; Ladeira, F.S.B., E-mail: Jacinta@ige.unicamp.br, E-mail: fsbladeira@ige.unicamp.br [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Instituto de Geociencias

    2015-07-01

    The National Forest of Ipanema (FLONA) is situated on a geological anomaly, known as 'Domo de Aracoiaba'. The soils of the area include Oxisols, Inceptsols and Alfisols. The amount of uranium and respective isotope activities in a soil depend on the parental rock and on the pedologic processes. The aim of this study was to investigate the activities for uranium isotopes ({sup 238}U, {sup 234}U, {sup 235}U) and the activity ratio (AR) {sup 234}U/ {sup 238}U or secular equilibrium for different soil types of the area collected at horizons A and B. The amount of uranium showed no significant differences for soils generated from alkaline intrusive rocks and sandstone, however, secular equilibrium was observed for Oxisol (RA = 1), while Inceptsol presented RA> 1 and the other soils, Alfisols, presented RA values <1. (author)

  11. Licensing of the Process Uranium Plant Mineral, Retortillo-Santidad; Licenciamiento de la Planta de Proceso de Mineral de Uranio Retortillo-Sanidad

    Energy Technology Data Exchange (ETDEWEB)

    Blazquez Arroyo, E.; Colilla Peletero, J.; Bellon del Rosal, F.; Mancipe Jimenez, D. C.; Garrido Delgado, C.; Garcia-Bermejo Fernandez, R.

    2013-07-01

    Berkeley Minera Spain, S.A. provides for the operation of the concession Retortillo-Santidad (Salamanca) mining and construction of a beneficiation plant of uranium ore, for the production of uranium concentrate (Yellow cake). In Spain, the project Quercus, ENUSA, obtained the last prior authorization in 1979. Since then, there has been a continuous evolution in the aspects technical and regulatory. This paper is the documentation and content necessary for the licensing of a uranium production plant. In particular, to obtain the prior authorization as radioactive installation of 1st category (RINR).

  12. Evaluation of parameters associated with monitoring in vivo of uranium isotopes in the lungs; Avaliacao de parametros associados a monitoracao in vivo de isotopos de uranio nos pulmoes

    Energy Technology Data Exchange (ETDEWEB)

    Juppa, Silvia P.; Lucena, Eder A.; Dantas, Bernardo M.; Dantas, Ana Leticia A., E-mail: adantas@ird.gov.br [Instiluto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Laboratorio de Monitoracao In Vivo. Divisao de Dosimetria

    2013-11-01

    The objective of this study is to evaluate the parameters associated with the technique of monitoring individuals exposed to uranium isotopes, aiming to optimize the technique and reduced uncertainties associated.

  13. Analysis of uncertainty of the uranium safeguard in CORAL-I; Analisis de incertidumbre de la Salvaguardia del Uranio en Coral-I

    Energy Technology Data Exchange (ETDEWEB)

    Blazquez, J.; Barrado, J. M.

    2013-07-01

    In this work is described the experimental procedure safeguard of U-235, it is possible to measure the enrichment and self-absorption coefficient of gamma discs using a Nal scintillation detector. Details are in the uncertainty analysis.

  14. Influence of the temperature in the uranium (Vi) sorption in zirconium diphosphate; Influencia de la temperatura en la sorcion de uranio (VI) en difosfato de circonio

    Energy Technology Data Exchange (ETDEWEB)

    Garcia G, N.; Solis, D. [Universidad Autonoma del Estado de Mexico, Facultad de Quimica, Paseo Colon y Paseo Tollocan, 50120 Toluca, Estado de Mexico (Mexico); Ordonez R, E., E-mail: nidgg@yahoo.com.mx [ININ, Departamento de Quimica, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2012-10-15

    In the present work was evaluated the uranium (Vi) sorption at 10, 20, 30, 40 and 60 C on the zirconium diphosphate (ZrP{sub 2}O{sub 7}). They were carried out kinetic and isotherms using the method by lots, these will allow to fix the sorption time (kinetic) and to explain the behavior of this sorption in different ph conditions and temperature (isotherm). The quantity of retained uranium in the surface was quantified by means of the fluorescence technique. (Author)

  15. Closure of mines uranium Haba (Badajoz) and Saelices El Chico (Salamanca); Clausura de las minas de uranio de la Haba (Badajoz) y Saelices El chico (Salamanca)

    Energy Technology Data Exchange (ETDEWEB)

    Lozano, F.; Ruiz Sanchez, J.

    2015-07-01

    The closure of the uranium mines of La Haba and Saelices el chico (Badajoz y Salamca provinces, respectively) are two examples of environmental restoration of mining uranium and dismantling of uranium concentrates plants. Activities carried out are described with the aim of ensuring that, once completed, environmental and radiological conditions are as similar as possible to the existing pre-exploitation, as well as the current situation in both sites with actions current and/or planned. (Author)

  16. Uranium and main oxides in soil in the Northeast part of Parana basil; Uranio e principais oxidos em solo na porcao nordeste da bacia do Parana, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Fagundes, I.C.; Bonotto, D.M.; Jimenez-Rueda, J.R., E-mail: fagundes.isabella@gmail.com, E-mail: dbonotto@rc.unesp.br, E-mail: jairorjr@rc.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Sao Paulo, SP (Brazil)

    2015-07-01

    Uranium is a litophile element that migrates to crust together with other light silicates. This work evaluated the relationships among the concentrations of uranium, major oxides (SiO{sub 2}, Al{sub 2}O{sub 3}, Na{sub 2}O, K{sub 2}O, CaO, MgO, Fe{sub 2}O{sub 3}, MnO, TiO{sub 2}, P{sub 2}O{sub 5}) and organic matter in different horizons of a soil profile located over siltstone from Tatui Formation, Piracicaba River sub-basin, Sao Paulo State, Brazil. Different techniques were utilized for data acquisition, for instance, alpha spectrometry, X-ray fluorescence spectrometry and smectrophotometry. The major U concentrations were found in horizons enriched in Fe{sub 2}O{sub 3}, indicating its tending to be retained in iron oxides. (author)

  17. Reuse of ammonium fluoride generated in the uranium hexafluoride conversion; Reutilizacao do fluoreto de amonio gerado na reconversao do hexafluoreto de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Silva Neto, J.B.; Carvalho, E.F. Urano de; Durazzo, M., E-mail: jbsneto@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Riella, H.G [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil)

    2010-07-01

    The Nuclear Fuel Centre of IPEN / CNEN - SP develops and manufactures dispersion fuel with high uranium concentration to meet the demand of the IEA-R1 reactor and future research reactors planned to be constructed in Brazil. The fuel uses uranium silicide (U{sub 3}Si{sub 2}) dispersed in aluminum. For producing the fuel, the processes for uranium hexafluoride (UF{sub 6}) conversion consist in obtaining U{sub 3}Si{sub 2} and / or U{sub 3}O{sub 8} through the preparation of intermediate compounds, among them ammonium uranyl carbonate - AUC, ammonium diuranate - DUA and uranium tetrafluoride - UF{sub 4}. This work describes a procedure for preparing uranium tetrafluoride by a dry route using as raw material the filtrate generated when producing routinely ammonium uranyl carbonate. The filtrate consists primarily of a solution containing high concentrations of ammonium (NH{sub 4}{sup +}), fluoride (F{sup -}), carbonate (CO{sub 3}{sup --}) and low concentrations of uranium. The procedure is basically the recovery of NH{sub 4}F and uranium, as UF{sub 4}, through the crystallization of ammonium bifluoride (NH{sub 4}HF{sub 2}) and, in a later step, the addition of UO{sub 2}, occurring fluoridation and decomposition. The UF{sub 4} obtained is further diluted in the UF{sub 4} produced routinely at IPEN / CNEN-SP by a wet route process. (author)

  18. Transport of uranium concentrates: low specific activity versus logistic complexity; Transporte de concentrado de uranio: baixa atividade especifica versus complexidade logistica

    Energy Technology Data Exchange (ETDEWEB)

    Dias, Pedro L.S.; Macedo, Eclesio F; Carvalho, Leonardo B; Carvalho, Renata R., E-mail: pedroluis@inb.gov.b, E-mail: eclesio@inb.gov.b, E-mail: leonardobernadino@inb.gov.b, E-mail: renatarangel@inb.gov.b [Industrias Nucleares do Brasil S.A., Caetite, BA (Brazil)

    2011-10-26

    This paper describes the case of radioactive material transport, according to pertinent documentation - nuclear material specifically in the form op ammonium diuranate, produced by Industrias Nucleares do Brasil S.A. - from the mine and physic-chemical processing at Caetite, Bahia, to the port of Salvador, state of Bahia, approaching the radiological protection aspects

  19. Study of the total uranium in underground water in the city of Jimenez, Chihuahua; Estudio del uranio total en agua subterranea en la Ciudad de Jimenez, Chihuahua

    Energy Technology Data Exchange (ETDEWEB)

    Renteria V, M. [Centro de Investigacion de Materiales Avanzados (CIMAV), Av. Miguel de Cervantes Saavedra 120, 31109 Chihuahua (Mexico)]. e-mail: marusia.renteria@cimav.edu.mx

    2004-07-01

    Samples of water of wells in the city of Jimenez, Chihuahua were analyzed, and its were determined the content of total uranium. It was used the technique of extraction of uranium from water adding Bis ( 2- ethylexyl) phosphate and scintillating Beta plate Hi safe, and the measures of the activities were carried out in the portable scintillation detector Thiathler- O Y HIDEX. The obtained interval of concentrations was 0.12 to 0.26 Bq/l that it is finds below the maximum permissible limits that it manages the Mexican regulation. It was found a significant correlation among the concentration of uranium and those total solid dissolved present in the samples. (Author)

  20. Overview of the uranium prospecting in Uruguay[Study of Uranium prospection in Uruguay]; Panorama de la prospeccion de Uranio en el Uruguay

    Energy Technology Data Exchange (ETDEWEB)

    Rossi, P; Vaz Chaves, N; Pirelli, H

    1985-07-01

    The report is about Uranium prospection in Uruguay by DINAMIGE experts. They were explained the radioactive properties elements in Uranium and its importance as a fuel oil for electric energy generation.

  1. Detection of sulphate reducer bacteria in effluents and sediment from uranium mine; Deteccao de bacterias redutoras de sulfato em efluente e sedimento em mina de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Sheila Kenia de

    2005-07-01

    One of the most serious environmental problems created by the mining industry is acid mine drainage. In one plant of Nuclear Industries of Brazil - INB, this problem is a matter of concern. The presence of iron sulfites, such as pyrite, generates water with acidity above the levels allowed by the legislation and therefore, inappropriate for releasing straight into the environment. The industry maintain a high cost treatment in acid water from mines and waste disposal which consists in neutralizing and precipitating heavy metals. The treatment of acid water sing SR B (sulfate-reducing bacteria) has been used in other countries with quite good technical results as well as economical advantages and thus, the object of this research. The use Sulfate Reducing Bacteria takes to a decreasing of the acidity by reducing sulfate to sulfite and precipitating the stable metals as sulfides. A seasonal study was carried out on the sulfate-reducing bacteria present in the liquid effluent discharged from two wastes disposal of the uranium mine, in phase of decommission, in Caldas/MG, Brazil. This study shows the presence of SRB in the analyzed environmental, as well as some factors that are related with the amount of SRB presents, such as: dissolved oxygen, pH and organic matter. SRB was presented in water samples with high concentrations of heavy metals and low pH values, as well as in samples with high oxygen levels. The sediment samples were the preferential place for SRB occurrence and site BF8 presented the highest values of SRB. (author)

  2. Diagram of the uranium prospection perforation[Study of the Uranium prospection in Uruguay]; Diagrama de las perforaciones de prospeccion de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Perrin, J

    1982-07-01

    We call diagrams to the drawn up one continuous of parameters physicists of the formation trimmed by a perforation based on the depth. The method is interesting not only for the putting in evidence of the mineralized levels but also it stops to determine the variations of lithology had by one part to the intrinsic properties of minerals (quartz, clays, carbonates) and to their variation of tenor and by another one, to variations of porosity and permeability of the formation.

  3. Recovery treatment for the non fissioned uranium in the production of Mo-99; Tratamiento de recuperacion del uranio no fisionado en la produccion de Mo-99

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez S, A.; Acosta C, A.L.; Lopez M, B.E

    1991-09-15

    An effective modification of the chemical processes has been obtained to dissolve at the uranium-IV and to extract it as uranyl triperoxidate that facilitates its manipulation and final conversion to uranyl nitrate like a concentrate of high purity. (Author)

  4. Exploration of Uranium. Report to the Government of the Eastern Republic of Uruguay; Prospeccion de uranio. Informe al gobierno de la Republica Oriental del Uruguay

    Energy Technology Data Exchange (ETDEWEB)

    Muset, J A [International Atomic Energy Agency, Vienna (Austria)

    1979-07-01

    The Government of Uruguay with IAEA assistance carried out the Uranium prospection project and the evolution of uraniferous minerals resources on this country soil. Several arrangement were did such as the recollection and analysis of the geologic material. The Uranium project began with radiometric anomalies and out crops.

  5. Uranium prospection programme: Paso de las Piedras mission. Technical report[Geochemical prospection of Uranium in Uruguay]; Programa prospeccion uranio: Mision Paso de las Piedras. Informe tecnico

    Energy Technology Data Exchange (ETDEWEB)

    Bossi, J; Mujica, H; Umpierre, M; Galipolo, N

    1966-07-01

    The mission of Paso de las Piedras was due of the radioactive values found by the French mission of the CE.A. found in a few former polls .Analyzed the samples its gave values that range between 2.500 and 3.000 ppm in uranium. The need to come to prospectar this zone was immediate, to determine if wil be before a deposit of uranium. The later studies prove that the extension was limited and not concluded yet. There were compiled 5 classes of numerical information in order of increasing detail: a) Chemical analysis of samples of alluvium b) chemical analysis of water samples c) report radiometric d) chemical analysis and radiometric report of soils e) chemical and radiometric analysis of the perforations.

  6. Uranium project. Borehole cutting with drill core[Study of Uranium prospection in Uruguay]; Proyecto uranio. cortes de los sondeos con testigos

    Energy Technology Data Exchange (ETDEWEB)

    Massa, J; Pirelli, H

    1984-07-01

    The topics included in these report are: explanatory note, number of wells and perforated length, key for the location of areas of perforation for the uranium prospection, maps of location of areas of perforation. The list of the drawn perforations and the references and drawings of the perforations.

  7. Irradiation of an uranium silicide prototype in RA-3 reactor; Irradiacion de un elemento combustible prototipo de siliciuro de uranio en el RA-3

    Energy Technology Data Exchange (ETDEWEB)

    Calabrese, R; Estrik, G; Notari, C [Comision Nacional de Energia Atomica, San Martin (Argentina). Unidad de Actividad Reactores y Centrales Nucleares

    1997-12-31

    The factibility of irradiation of an uranium silicide (U{sub 3} Si{sub 2}) prototype in the RA-3 reactor was studied. The standard RA-3 fuel element uses U{sub 3} O{sub 8} as fissible material. The enrichment of both standard and prototype is the same: 20% U{sub 235} and also the frame geometry and number of plates is identical. The differences are in the plate dimensions and the fissile content which is higher in the prototype. The cooling conditions of the core allow the insertion of the prototype in any core position, even near the water trap, if the overall power is kept below 5Mw. Nevertheless, the recommendation was to begin irradiation near the periphery and later on move the prototype towards more central positions in order to increase the burnup rate. The prototype was effectively introduced in a peripheral position and the thermal fluxes were measured between plates with the foil activation technique. These were also evaluated with the fuel management codes and a reasonable agreement was found. (author). 5 refs., 3 figs., 3 tabs.

  8. Preparation of uranium dioxide by thermal decomposition and direct reduction of ammonium uranate; Preparacion del dioxido de uranio por descomposicion termica y reduccion directa del uranato de amonio

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez R, R

    1996-12-31

    The thermal decomposition of ammonium uranate has been studied by infrared spectroscopy, and X-ray diffraction. It has been show that ammonia remains in the solid until substantially 350 Centigrade degrees, when gaseous nitrogen is released. It is concluded that compounds derived from the calcination of ammonium uranate at atmospheric pressure, produced amorphous U O{sub 3} at about 350-400 Centigrade degrees and transform to U{sub 3} O{sub 8} via {alpha} - U O{sub 3} and/or {alpha} - U O{sub 3}. The object of this study was to obtain reliable fundamental information regarding the character of the pure carbon monoxide-ammonium uranate-uranium trioxide-uranium octaoxide reaction, in the range of temperatures that has been used in commercial reduction processes. Through the use of high-purity samples and by the proper control of incidental variable, this object was realized. (Author).

  9. Analytical strategies for uranium determination in natural water and industrial effluents samples; Estrategias analiticas para determinacao de uranio em amostras de aguas e efluentes industriais

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Juracir Silva

    2011-07-01

    The work was developed under the project 993/2007 - 'Development of analytical strategies for uranium determination in environmental and industrial samples - Environmental monitoring in the Caetite city, Bahia, Brazil' and made possible through a partnership established between Universidade Federal da Bahia and the Comissao Nacional de Energia Nuclear. Strategies were developed to uranium determination in natural water and effluents of uranium mine. The first one was a critical evaluation of the determination of uranium by inductively coupled plasma optical emission spectrometry (ICP OES) performed using factorial and Doehlert designs involving the factors: acid concentration, radio frequency power and nebuliser gas flow rate. Five emission lines were simultaneously studied (namely: 367.007, 385.464, 385.957, 386.592 and 409.013 nm), in the presence of HN0{sub 3}, H{sub 3}C{sub 2}00H or HCI. The determinations in HN0{sub 3} medium were the most sensitive. Among the factors studied, the gas flow rate was the most significant for the five emission lines. Calcium caused interference in the emission intensity for some lines and iron did not interfere (at least up to 10 mg L{sup -1}) in the five lines studied. The presence of 13 other elements did not affect the emission intensity of uranium for the lines chosen. The optimized method, using the line at 385.957 nm, allows the determination of uranium with limit of quantification of 30 {mu}g L{sup -1} and precision expressed as RSD lower than 2.2% for uranium concentrations of either 500 and 1000 {mu}g L{sup -1}. In second one, a highly sensitive flow-based procedure for uranium determination in natural waters is described. A 100-cm optical path flow cell based on a liquid-core waveguide (LCW) was exploited to increase sensitivity of the arsenazo 111 method, aiming to achieve the limits established by environmental regulations. The flow system was designed with solenoid micro-pumps in order to improve mixing and minimize reagent consumption, as well as waste generation. A linear response was observed from 5.0 to 150.0 {mu}g L{sup -1}, with a detection limit, RSD, and sampling rate estimated as 1.3 {mu}g L{sup -1} (99.7% confidence level), 0.7% (n = 20), and 40 determinations per hour, respectively. The consumption of arsenazo 111 was reduced in 1250-fold in comparison to a procedure with preconcentration in solid phase. The accuracy of the methods was confirmed by analysis of two laboratory reference materials. In addition, an effluent sample was analyzed by inductively coupled plasma mass spectrometry (ICP-MS), and the observed recovery was satisfactory. The developed methods were applied to the determination of uranium in river, well and drinking water and industrial effluent collected from uranium-producing mine in Caetite city, Brazil. The results for uranium in drinking water samples from Caetite city were below the limit of quantification of methods, except for well water (17.0 +- 0.8 mg L{sup -1}) and a river water collected near of the mine (9.6 +- 0.8 mg L{sup -1}). (author)

  10. Study and development of refractory coatings for metallic uranium fusion and evaporation; Estudo e desenvolvimento de suportes refratarios para a fusao e a evaporacao de uranio metalico

    Energy Technology Data Exchange (ETDEWEB)

    Vasconcelos, Getulio de

    2004-07-01

    In melting process or evaporation of metallic uranium, the reaction with the crucible and the possible contamination of the molten metal should be avoided. This effect can be reduced using an inert and protective coating on the crucible walls. The selection of the coating should be based on the chemical inertia and the kinetic of the reaction products. By avoiding chemical reactions, the amount of impurities in the molten metal can be reduced, leading to an increased crucible lifetime. This work presents a comparative study among different crucible coatings used in the melting process of metallic uranium, at temperatures above its melting point. Samples of metallic uranium are melted in contact with different materials in a vacuum furnace. The reactions occur at a given temperature during a certain time interval; samples are then cooled down to room temperature. Finally, samples are characterized by optical and electronic microscopy, dispersive X-ray spectroscopy, surface roughness and X-ray diffraction. Samples preparation consists of polishing selected areas, and milling the reaction products originated from the corroded interfaces. The extent of the reactions is determined as a function of the temperature by optical microscopy and roughness analyses. The compositions of the reacted products are determined by Energy Dispersive Spectroscopy, and the phase changes by X-ray diffraction. The results indicate that alumina presented higher activation energy (39 kcal.mol{sup -1}) than magnesia (12 kcal.mol{sup -1}), otherwise, it is corroded faster. On the other hand, the alumina could be protected by a thick coating of titanium nitride, because no rection between titanium nitride and uranium was observed at temperatures near to 1700 K. After cooling to the room temperature, there is stress concentration between the graphite and the TiN layer, generating a compressive stress of 0,5 GPa. When uranium is deposited on the TiN, a tensile stress is generated in this new layer, which is inversely proportional to the layer thickness. By increasing the uranium layer thickness, TiN loosens itself from the graphite. (author)

  11. Fluor determination by alkaline hydrolysis of the uranium and thorium fluorides; Determinacion de fluor por hidrolisis alcalina en fluoruros de uranio y torio

    Energy Technology Data Exchange (ETDEWEB)

    Barrachina Gomez, L; Gasco Sanchez, L

    1961-07-01

    The alkaline hydrolysis of the uranium and thorium fluorides is studded and a new method for the determination of the fluoride, on the basis of a indirect volumetric titration with standard soda, is proposed. The compounds that may influence the hydrolysis of the uranium fluoride and that may be occasionally found in it as impurities are also studied. the method can be applied to the uranium fluoride except when there is a great quantity of F{sub 2}UO{sub 2} or UO{sub 3} present in the sample. (Author) 20 refs.

  12. Technological study of electrochemical uranium fuel reprocessing in fused chloride bath; Estudo tecnologico do reprocessamento eletroquimico de combustiveis de uranio em meio de cloretos fundidos

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Damaris

    2002-07-01

    This study is applied to metallic fuels recycling, concerning advanced reactor concept, which was proposed and tested in LMR type reactors. Conditions for electrochemical non-irradiated uranium fuel reprocessing in fused chloride bath in laboratory scale were established. Experimental procedures and parameters for dehydration treatment of LiCl-KCl eutectic mixture and for electrochemical study of U{sup 3+}/U system in LiCl-KCl were developed and optimized. In the voltammetric studies many working electrodes were tested. As auxiliary electrodes, graphite and stainless steels crucibles were verified, with no significant impurities inclusions in the system. Ag/AgCl in Al{sub 2}O{sub 3} with 1 w% in AgCl were used as reference electrode. The experimental set up developed for electrolyte treatment as well as for the study of the system U{sup 3+}/U in LiCl-KCl showed to be adequate and efficient. Thermogravimetric Techniques, Scanning Electron Microscopy with Energy Dispersive X-Ray Spectrometry and cyclic voltametry showed an efficient dehydration method by using HCl gas and than argon flux for 12 h. Scanning Electron Microscopy, with Energy Dispersive X-Ray Spectrometry and Inductively Coupled Plasma Emission Spectrometry and DC Arc Emission Spectrometry detected the presence of uranium in the cadmium phase. X-ray Diffraction and also Inductively Coupled Plasma Emission Spectrometry and DC Arc Emission Spectrometry were used for uranium detection in the salt phase. The obtained results for the system U{sup 3+}/U in LiCl-KCl showed the viability of the electrochemical reprocessing process based on the IFR advanced fuel cycle. (author)

  13. Measurement of uranium concentration by molecular absorption spectrophotometry by means optical fibers; Medicion continua de concentracion de uranio por espectrofotometria de absorcion molecular mediante fibras opticas

    Energy Technology Data Exchange (ETDEWEB)

    Gauna, Alberto C.; Pascale, Ariel A. [Comision Nacional de Energia Atomica, Buenos Aires (Argentina). Centro Atomico Ezeiza. Agencia Minipost

    1996-07-01

    An on-line method for measuring the concentration of uranium in uranyl nitrate-nitric acid aqueous solutions is described. The method is based on molecular absorption spectrophotometry with transmission of light by means of optical fibers. It is ideally suited for control and processes development applications. (author)

  14. Uranium recovery and uranium remove from acid mine waters by ion exchange resin; Remocao e recuperacao de uranio de aguas acidas de mina com resina de troca ionica

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, Marcos R.L. [Comissao Nacional de Energia Nuclear (CNEN), Pocos de Caldas, MG (Brazil). Coordenacao do Laborarorio; Fatibello Filho, Orlando [Sao Carlos Univ., SP (Brazil). Dept. de Quimica

    1999-11-01

    Ion exchange using resins is one of few processes capable of reducing contaminants in effluents to very low levels according to environmental legislation. In this study the process was used to remove and recovery uranium from acid mine waters at Pocos de Caldas-MG Uranium Mining and Milling Plant. The presence of pyrite in the waste rock piles, resulting acid drainage with several pollutants. Including uranium ranging from 6 to 14 mg/l, as sulfate complex, that can be removed by an anionic exchanger. Studies of uranium sorption without treatment, and with lime pretreatment of water to precipitate the iron and recovery uranium as commercial product, are presented. Uranium elution was done with NaCl solutions. Saline concentration and retention time were the parameters studied. the uranium decontaminations level in the effluents from acid mine water was 94%. (author) 10 refs., 6 tabs., 3 figs.

  15. Electrocoagulation applied to the decontamination of stainless steel parts contaminated with uranium; Electrocoagulacion aplicada a la descontaminacion de piezas de acero inoxidable contaminadas con uranio

    Energy Technology Data Exchange (ETDEWEB)

    Pujol P, A. A.; Monroy G, F. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Bustos B, E., E-mail: apujol@cideteq.mx [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, S. C., Parque Sanfandila s/n, Pedro Escobedo, 76703 Santiago de Queretaro, Qro. (Mexico)

    2017-09-15

    The decontamination of non-compact able radioactive waste, such as tools and equipment, has the purpose of removing surface radioactive waste from waste, in order to reduce its volume to be conditioned and stored. The application of treatment techniques based on electrochemistry, such as electro-coagulation (Ec) in the decontamination of waste or non-compact able radioactive materials of stainless steel containing uranium, was studied in the present work and its technical feasibility was evaluated. For this, tests were carried out, first with stainless steel plates coated with WO{sub 3}, to simulate a fixed contamination and to determine the best conditions of tungsten removal by Ec as: ph, support electrolyte, cell potential, type of counter electrode material and distance between the anode/cathode electrodes. In addition, different arrangements of configurations were tested for a rectangular acrylic cell and for a circular configuration cell, using flat plate electrodes and cylindrical electrodes to perform the removal process of the contaminant with the best conditions. In the case of the Ec, the mechanism that occurs is an electrodisolution of the iron plate, with the release of oxygen at the anode and detachment of the WO{sub 3} layer, all the material passing to the solution with the formation of iron hydroxides. Subsequently, from the best experimental conditions to remove WO{sub 3}, UO{sub 2} (NO{sub 3}) {sub 2} was used as radioactive contaminant to evaluate the feasibility of the decontamination process. Removal efficiencies of 90% uranium were obtained in 1 hour, ph = 1, using a molar solution of H{sub 2}SO{sub 4} as support electrolyte and potential of 2.4 V. Finally, after testing the different electrochemical cell (Ec) arrays at the laboratory level, radioactive decontamination of real pieces contaminated with U-238 was performed using the circular configuration arrangement under the best experimental conditions previously determined. (Author)

  16. Uranium determination by spectrophotometry, in chloride solutions, using titanium (III) as reducer; Determinacao de uranio por espectrofotometria, em solucoes cloridricas, utilizando titanio (III) como redutor

    Energy Technology Data Exchange (ETDEWEB)

    Bastos, E T.R.; Bastos, M B.R.

    1986-08-01

    A simple method for determining uranium in uranium (VI) solutions with the presence of uranium (IV), iron (II), and titanium (IV) in chloridic solution is described. The method comprises in uranium (VI) reduction with titanium (III), acidity adjustment and uranium (IV) spectrophotometry in hydrochloric acid 2 M. (C.G.C.).

  17. Potentiometric titration of uranium reduced by chromic salts in chloridic solutions; Titulacao potenciometrica de uranio reduzido por sais cromosos em solucoes cloridricas

    Energy Technology Data Exchange (ETDEWEB)

    Coutinho, C M.C.; Bastos, E T.R.

    1986-06-01

    The utilization of chromic salts for reducing the uranium (VI) from chloridic solutions, for potentiometric dosage is described. This method is used in the range of 0,002 to 1,0 M of uranium. (C.G.C.).

  18. Direct determination of uranium in human urine by Icp-SFMS; Determinacion directa de uranio en orina humana por ICP-SFMS

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez M, H. [ININ, Departamento de Quimica, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Yllera de Ll, A., E-mail: hector.hernandez520@gmail.com [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, Departamento de Medio Ambiente, Av. Complutense 22, 28040 Madrid (Spain)

    2013-10-15

    The success of the measurement and the evaluation of the internal exposure are highly dependent of the effective capacities for the radiation measurement in biological samples (mainly urine and the feces). Usually, during the samples bioassay of human urine, a pre-concentration and purification of the radionuclides is carried out previously to the quantitative analysis. These stages, as the analysis time are the main source of uncertainty in the measurement process. In the uranium case, this is not necessary when are used mass spectrometry techniques, in particular, Mass Spectrometry of Magnetic Sector with Inductively Coupled Plasma (Icp-SFMS). This work presents the results obtained for the uranium analysis in samples of human urine during the participation in the inter-comparison exercises of the Association pour la Promotion de Controle de Qualite des Analyses de Biologie Medicale en Radiotoxicologie (PROCORAD) in the period 2010 and 2011. The analyses were realized directly in the diluted urine samples (dilution factor 1:20) in 5% of HNO{sub 3}. The obtained results, were normalized to the total urine sample (V = 0.5 L), these values coincide with the waited reference values of uranium in the urine sample. Additionally, were calculated the detection limits of {sup 235}U= 0.049 x 10{sup -3} μg L{sup -1} and {sup 238}U= 7.37 x 10{sup -3} μg L{sup -1}. (author)

  19. Environmental conditioning on uranium surface distribution in the tropical region; Condicionantes ambientais sobre a distribuicao superficial de uranio numa regiao de climatologia tropical

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Heitor Evangelista da; Licinio, Marcus V.S.; Miranda, Marcio R. [Universidade do Estado, Rio de Janeiro, RJ (Brazil). Lab. de Ciencias Radiologicas

    2001-07-01

    Based on a high resolution aerogammaspectrometer survey over the State of Rio de Janeiro, it is presented an associative study of equivalent uranium concentration and environmental parameters. The aspects considered in this study included geological domains like Sandys, Gnaisses, Granites, Xists; soils domains like Organic and Alluvial ones, Litolic, Glei, Podzolic, Red-yellow, Latossolo, Planossolo, Red bruizem, Cambissolo, Hidromorphic Podzol, Yellow latossolo; geomorphology (Coast Plains and River Accumulation Land, Coast Tabulators, Pomba-Muriae Rivers Spread Depression, Northern Mantiqueira, main Hills and Coastal Rock Massifs, Steep slopes and Reverses of Serra do Mar Mountain Range ,Serra dos Orgaos Mountain Range and Bocaina Tablelands), Paraiba do Sul Crests Alignment, Medium Paraiba do Sul Depression); influence of mean annual rain intensity and hydrographical categories were also evaluated. Geoprocessing of each environmental data base at the same cartographical base of uranium surface distribution was the basic methodology employed. (author)

  20. Effect of anaerobic contributions to the uranium content in marine sediments; Efecto de aportes anaerobios en el contenido de uranio en sedimentos marinos

    Energy Technology Data Exchange (ETDEWEB)

    Ordonez R, E. [ININ, Departamento de Quimica, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Ruiz F, A. C. [UNAM, Instituto de Ciencias del Mar y Limnologia, Unidad Academica Mazatlan, Cap. Joel Montes Camarena, Cerro del Vigia, 82040 Mazatlan, Sinaloa (Mexico); Jimenez D, E.; Guerrero J, M., E-mail: eduardo.ordonez@inin.gob.mx [Universidad Autonoma del Estado de Mexico, Facultad de Planeacion Urbana y Regional, Paseo Tollocan esq. Mariano Matamoros, 50130 Toluca, Estado de Mexico (Mexico)

    2014-10-15

    In this work a sediment group obtained in the seabed near the mouth of the Santiago River, physical analyzes show that there is little activity of microscopic marine life, revealed by exoskeletons of foraminifera. Although the amount of organic matter occurs normally, around 20%, is assumed that this contribution is due to the large amount of organic waste scattered by the effluent of the river, causing an abnormally high anaerobic activity, clearly shown by the large amount of pyrite specific framboids found along the nucleus profile of 23 cm of sediment. In the analyzed fractions the uranium concentration and its isotope ratio was studied: which vary from 3.19 Bq/kg for the more superficial fractions down gradually to less than 1 Bq/kg for deeper fractions. An outstanding fact is that the surface fractions have an isotope ratio {sup 234}U/{sup 238}U unusually low for fractions 1-4 cm of deep, close to 0.4, indicating a strong reaction of few years ago on the radiogenic descendants of {sup 238}U, leaching essentially the {sup 234}Th and causing this abnormal radioactive imbalance. The plutonium has become an element found commonly in the surface layers of the sea and coastlines, finding in the top layer an activity of 2.78 Bq/kg ({sup 239}Pu + {sup 240}Pu). The high contamination of the mouth of Santiago River has changed the conditions of the micro fauna as well as of the chemical equilibrium of the natural elements. (Author)

  1. Preparation of mixed oxides (Th,U)O{sub 2}: an evaluation of different techniques; Estudos de diferentes rotas de preparacao de oxidos binarios de torio e uranio

    Energy Technology Data Exchange (ETDEWEB)

    Ayoub, Jamil Mahmoud Said

    1999-07-01

    An evaluation of different ways of obtaining (Th-U)O{sub 2} mixed oxides is described. Coprecipitation, mechanical mixing of uranium and thorium powders, and the sol-gel technique were studied in order to get a large spectrum of knowledge of the process performance. The use of ultrasonic waves for the homogenization of the hydroxide mixture and microwave heating for powder drying was also investigated. Sol-gel showed the best results regarding the specific area for obtained samples. Oxide drying by microwave is an effective method to get mixed oxides for fuel fabrication. Neither coprecipitation nor mechanical mixing of the thorium and uranium oxide powders is suitable for the purpose. The obtained data are less than 70% than those achieved when sol-gel process is performed. Electronic microscopy, X-ray fluorescence and diffraction, thermogravimetry, specific gravidity and specific area determination (BET) used for sample characterization were convenient and accomplished good results. (author)

  2. Model for the behaviour of thorium and uranium fuels at pelletization; Modelo para o comportamento de microesferas combustiveis de torio e uranio na peletizacao

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira Neto, Ricardo Alberto

    2000-11-15

    In this work, a model for the behaviour of thorium-uranium-mixed oxide microspheres in the pelletizing process is presented. This model was developed in a program whose objective was to demonstrate the viability of producing fissile material through the utilization of thorium in pressurized water reactors. This is important because it allows the saving of the strategic uranium reserves, and makes it possible the nuclear utilization of the large brazilian thorium reserves. The objective was to develop a model for optimizing physical properties of the microspheres, such as density, fracture strength and specific surface, so as to produce fuel pellets with microstructure, density, open porosity and impurity content, in accordance with the fuel specification. And, therefore, to adjust the sol-gel processing parameters in order to obtain these properties, and produce pellets with an optimized microstructure, adequate to a stable behaviour under irradiation. The model made it clear that to achieve this objective, it is necessary to produce microspheres with density and specific surface as small as possible. By changing the sol-gel processing parameters, microspheres with the desired properties were produced, and the model was experimentally verified by manufacturing fuel pellets with optimized microstructures, density, open porosity and impurity content, meeting the specifications for this new nuclear fuel for pressurized water reactors. Furthermore it was possible to obtain mathematical expressions that enables to calculate from the microspheres properties and the utilized compaction pressure, the sinter density that will be obtained in the sintered pellet and the necessary compaction pressure to reach the sintered density specified for the fuel. (author)

  3. Individual monitoring program for internal contamination by inhaled uranium. Programacion de los controles dosimetricos individuales para contaminacion interna por inhalacion de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez, C.; Chapel, M.L.; Saenz, R.

    1988-02-01

    The metabolic behaviour of inhaled uranium is studied. using a particular analytical method applied to the models and dose assessment methods recommended by ICRP, The organ committed equivalent dose and effective equivalent dose are calculated. The exact ALI and DAC are derived from there. In the paper, the influence that various parameters have on those results are considered for the specific case of a particular nuclear element fabrication factory. Different AMAD and solubility type of inhaled material are specially analyzed. The results show the paramount importance of some of these parameters on the secondary and derived dose limits. Relationships between the real intake, as a fraction of ALI, and the lung retention or urine excretion are ahown for different cases ands intake forms hypothesis. Minimum dsetectable intakes with the available experimental techniques are then established.

  4. The determination of phosphorus in uranium minerals and resulting solutions; Determinacion de fosforo en minerales de uranio y soluciones procedentes de su beneficio

    Energy Technology Data Exchange (ETDEWEB)

    Petrement Eguiluz, J C; Rarellada Bellod, R; Fernandez Cellini, R

    1964-07-01

    Interferences of several elements present in Spanish uranium minerals in the phosphorus determination by the spectrophotometrical method of the molibdovanada te phosphoric acid are studied. A method is described with a previous separation of these element by a cationic resin. This method is successfully applied to the phosphorus determination in acid or alkaline lixiviation solutions of uranium minerals, as well as in the evaluates of ion exchange resins used used technically for the concentration of solutions with a low uranium content. (Author) 11 refs.

  5. Methods of Uranium Determination in solutions of Tributyl Phosphate and Kerosene; Metodos de determinacion de uranio en soluciones de fosfato de tributilo y queroseno

    Energy Technology Data Exchange (ETDEWEB)

    Petrement Eguiluz, J; Palomares Delgado, F

    1962-07-01

    A new analytical method for the determination of uranium in organic solutions of tributyl phosphate and kerosene is proposed. In this method the uranium is reectracted from the aqueous phase by reduction with cadmium in acid solution. The uranium can be determined in this solution by the usual methods. In case of very diluted solutions, a direct spectrophtometrical determination of uranium in the organic phase with dibenzoylmethane is proposed. (Author) 21 refs.

  6. Control estructural sobre el plutón Los Ratones y la mineralización de uranio en la Sierra de Fiambalá, Sierras Pampeanas, Catamarca

    International Nuclear Information System (INIS)

    Hongn, F.; Kirschbaum, A.; Ferreira, L.; Morello, O.; Guidi, F.; Anesa, J.; Rubinstein, N.

    2010-01-01

    The Carboniferous Los Ratones pluton is composed by two main facies: equigranular and porphyric. The uranium mineralization hosted by the metamorphic rock on the NW border of the pluton is related to a fluor- rich greisen related to the equigranular facies. The detailed mapping of the pluton host rock and the uranium mineralization shows a well-defined structural control on both the granite emplacement, particularly on the porphyric facies, and on the migration of the mineralized fluids. Four sets of fractures participate on this control. The two main with N and NE trends coincide clearly with the west and northwest border of the pluton as well as with the high-grade uranium manifestations. The third and fourth ones respectively corresponds to E-W and NW striking fractures, which are less developed in relation to the main fractures considering their frequency and size. Fractures of the four sets are high dipping close to vertical, attitude corroborated by geophysical studies in the area where the NE fractures are the best developed. In addition to the mentioned features, granite-related acidic and basic dikes follow mainly these orientations. The fracture sets seem to be related to a high-east dipping meridian fault system with right horizontal main movement component and subordinate normal displacement. These faults partially reactivated heterogeneities of the metamorphic rocks, mainly the dominant foliation. Changes on the strike of these fractures formed dilatant zones where magmatism and related mineralization were concentrated. (authors) [es

  7. Norms of radiation protection in uranium and thorium production cycles. Normas de protecao radiologica nos ciclos de producao do uranio e torio

    Energy Technology Data Exchange (ETDEWEB)

    1975-01-01

    A deliberation aiming to complement the basic norms of radiation protection for applying to uranium and thorium production cycle is presented. The activitires of excavation, remotion, storage, and physical and chemical processing of the ores, are included. The transport of radioactive materials into the establishments is governed by these norms. (M.C.K.).

  8. Considerations on the analytic control of sulphide tracks in metal uranium; Consideraciones osbre el control analitico de trazas de azufre (sulfuro) en uranio metal

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez Cellini, R; Gasco Sanchez, C

    1956-07-01

    Volumetric and colorimetric determinations of sulphur (sulphide) in uranium have been carried out by acid treatment and evaluation of SH{sub 2}. According to the experimental results a discussion of both methods has been made. (Author)

  9. Uranium reserves and the economic factors for their transformation in electricity; Reservas de uranio y los factores economicos para su transformacion en electricidad

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz M, J. R. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2009-07-01

    In diverse national and international forums, it is has come discussing the idea that the nuclear energy can offer a valuable contribution to the electricity demand and the gases emission of greenhouse effect, due to its unique characteristics in terms of energy density, environmental sustainable and economic viability. Before this panorama it is convenient to meditate about the current situation of the uranium reserves and the economic factors that impact in their conversion to arrive to the nuclear fuel and of there to the electric generation, with the purpose of establishing the available levels of sufficiency, considering the current consumption tendencies, as the increase scenarios. Starting from an analysis about the uranium reserves, the purpose of this work is to make a description of the phases of the nuclear fuel cycle, considering the technological options that there is, as well as the repercussion of its economic aspects. (Author)

  10. Determination of uranium traces in fuel cans of nuclear reactors; Determinacion de trazas de uranio en vainas de combustible de reactores nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Acosta L, C.E.; Benavides M, A.M.; Sanchez P, L.A.; Nava S, G.F. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1997-07-01

    The objective of this work is to quantify the uranium content that as impurity can be found in zircon and zircaloy alloys which are used in the construction of fuel cans. The determination of this serves as a quality control measure due to that the increment of uranium content in alloy, diminishing the corrosion resistance. The fluorimetric method was used to do this determination. It is a very sensitive, reliable, rapid method also high reproducibility and repeatability as well as low detection limits (0.25 mg/kg). (Author)

  11. Environmental monitoring of the Uranium Concentrate Unity (URA) at Caetite - Bahia State - Brazil; Monitoracao ambiental da Unidade de Concentrado de Uranio (URA) em Caetite - BA - Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Wagner de Souza; Py Junior, Delcy de Azevedo [Industrias Nucleares do Brasil SA, Resende, RJ (Brazil). Gerencia de Licenciamento em Meio Ambiente]. E-mail: glima@inb.gov.br

    2002-07-01

    The pre operational monitoring program has been executed in order to set a baseline, on which comparisons with the same points and the same radionuclides will be made after beginning of operation, having the objective of environmental impact evaluation, in the vicinity of the installation. The program was held in the period of 1982 to 1999, collecting non biological environmental samples (aerosol, rain water, surface water, underground water soil and sediment) and samples that are related to the human food chain (manioc, manioc flour, milk, browse, fish, been, corn, cactus and silage). The analyzed radionuclides are natural uranium, natural thorium, Ra-226, Ra-228, Rn-222 and Pb-210. This work intends to analyze data from the last ten years, program (1989 - 1999), analyzing approximately 350 biological samples and 3500 non biological samples, in order to establishing the baseline to be used in future studies of environmental impact. (author)

  12. Fabrication procedures for manufacturing high uranium concentration dispersion fuel elements; Procedimentos de fabricacao de elementos combustiveis a base de dispersoes com alta concentracao de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Souza, J.A.B.; Durazzo, M., E-mail: jasouza@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2010-07-01

    IPEN developed and made available for routine production the technology for manufacturing dispersion type fuel elements for use in research reactors. However, the fuel produced at IPEN is limited to the uranium concentration of 3.0 gU/cm{sup 3} by using the U{sub 3}Si{sub 2}-Al dispersion. Increasing the uranium concentration of the fuel is interesting by the possibility of increasing the reactor core reactivity and lifetime of the fuel. It is possible to increase the concentration of uranium in the fuel up to the technological limit of 4.8 gU/cm{sup 3} for the U{sub 3}Si{sub 2}-Al dispersion, which is well placed around the world. This new fuel will be applicable in the new Brazilian-Multipurpose Reactor RMB. This study aimed to develop the manufacturing process of high uranium concentration fuel, redefining the procedures currently used in the manufacture of IPEN. This paper describes the main procedures adjustments that will be necessary. (author)

  13. Fabrication procedures for manufacturing high uranium concentration dispersion fuel elements; Procedimentos de fabricacao de elementos combustiveis a base de dispersoes com alta concentracao de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Jose Antonio Batista de

    2011-07-01

    IPEN-CNEN/SP developed the technology to produce the dispersion type fuel elements for research reactors and made it available for routine production. Today, the fuel produced in IPEN-CNEN/SP is limited to the uranium concentration of 3.0 gU/cm{sup 3} for U{sub 3}Si{sub 2}-Al dispersion-based and 2.3 gU/cm{sup 3} for U{sub 3}O{sub 8}-Al dispersion. The increase of uranium concentration in fuel plates enables the reactivity of the reactor core reactivity to be higher and extends the fuel life. Concerning technology, it is possible to increase the uranium concentration in the fuel meat up to the limit of 4.8 gU/cm{sup 3} in U{sub 3}Si{sub 2}-Al dispersion and 3.2 gU/cm{sup 3} U{sub 3}O{sub 8}-Al dispersion. These dispersions are well qualified worldwide. This work aims to develop the manufacturing process of both fuel meats with high uranium concentrations, by redefining the manufacturing procedures currently adopted in the Nuclear Fuel Center of IPEN-CNEN/SP. Based on the results, it was concluded that to achieve the desired concentration, it is necessary to make some changes in the established procedures, such as in the particle size of the fuel powder and in the feeding process inside the matrix, before briquette pressing. These studies have also shown that the fuel plates, with a high concentration of U{sub 3}Si{sub 2}-Al, met the used specifications. On the other hand, the appearance of the microstructure obtained from U{sub 3}O{sub 8}-Al dispersion fuel plates with 3.2 gU/cm{sup 3} showed to be unsatisfactory, due to the considerably significant porosity observed. The developed fabrication procedure was applied to U{sub 3}Si{sub 2} production at 4.8 gU/cm{sup 3}, with enriched uranium. The produced plates were used to assemble the fuel element IEA-228, which was irradiated in order to check its performance in the IEA-R1 reactor at IPEN-CNEN/SP. These new fuels have potential to be used in the new Brazilian Multipurpose Reactor - RMB. (author)

  14. Inorganic oxides as alternative in the separation of non fissioned residual uranium; Oxidos inorganicos como alternativa en la separacion del uranio residual no fisionado

    Energy Technology Data Exchange (ETDEWEB)

    Baca G, A

    1997-07-01

    The Al{sub 2}O{sub 3}, SiO{sub 2} and SnO{sub 2} as well as vegetable carbon have been studied for its possible use as sorbent in the concentration and separation of non fissioned residual uranium of some fission products such as: {sup 141} Ce, {sup 134} Cs, {sup 125} Sb, {sup 103} Ru, {sup 95} Zr, {sup 95} Nb of alkaline aqueous systems. The separation efficiency has been evaluated using natural uranium and radionuclides in static and dynamic processes, through liquid scintillation and gamma spectrometry. Therefore Al{sub 2}O{sub 3}, SiO{sub 2}, SnO{sub 2} and carbon were pre-treated thermic and chemically and characterized through the technique of Nitrogen absorption analysis, X-ray diffraction and IR spectroscopy. By means of the p H determination and the aqueous system potential the present hydrolysis products were determined. The inorganic oxides show structural and surface changes due to the treatment. The adsorption process is realized by different mechanism depending of the sorbent. The results show that the retention capacity is a dependence of the oxides pre-treatment and of the hydrolysis products in the aqueous system, as well as of the experimental conditions. Not in this way for carbon in which the results show the treatment and the experimental conditions significantly have not influence in its adsorption capacity. (Author)

  15. Control of radiological impacts in deactivated uranium mine - the portuguese experience; Controlo dos impactes radiologicos em minas de uranio desactivadas - a experiencia portuguesa

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Alcides; Neves, Luis, E-mail: apereira@dct.uc.p, E-mail: luis.neves@dct.uc.p [Universidade de Coimbra (Portugal). Dept. de Ciencias da Terra. Instituto do Mar

    2011-10-26

    The exploration of radioactive ores occurred in Portugal during around 100 years, and on that period 4370 tons were produced of uranium concentrate, and an estimated total of 13 millions of tons of residues, of various type and variable dangerous grade. From the year 2000 that the government has been performed studies on environmental characterization at the mining areas and remediation project as well. The precise evaluation of the environmental impacts implies the the knowledge of prior work situation, nonexistent for the case of Portuguese mines. This work proposes a methodology for exceeding that limitation focused on selection of area sited at the same metallogenetic province, and considered representative of background. The radiological impacts are checked by the effective dose calculated for reference groups of the exposed population, at this region and in the principal mining area at Portugal (Urgeirica), at the end of exploration and after the finalization of some remediation works

  16. Analytical control of reducing agents on uranium/plutonium partitioning at purex process; Controle analitico dos agentes redutores na particao uranio/plutonio no processo purex

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Izilda da Cruz de

    1995-07-01

    Spectrophotometric methods for uranium (IV), hydrazine (N{sub 2}H{sub 4}) and its decomposition product hydrazoic acid(HN{sub 3}), and hydroxylamine (NH{sub 2} OH) determinations were developed aiming their applications for the process control of CELESTE I installation at IPEN/CNEN-SP. These compounds are normally present in the U/Pu partitioning phase of the spent nuclear treatment via PUREX process. The direct spectrophotometry was used for uranium (IV) analysis in nitric acid-hydrazine solutions based on the absorption measurement at 648 nm. The azomethine compound formed by reaction of hydrazine and p-dimethylamine benzaldehyde with maximum absorption at 457 nm was the basis for the specific analytical method for hydrazine determination. The hydrazoic acid analysis was performed indirectly by its conversion into ferric azide complex with maximum absorption at 465 nm. The hydroxylamine detection was accomplished based on its selective oxidation to nitrous acid which is easily analyzed by the reaction with Griess reagent. The resulted azocompound gas a maximum absorption at 520 nm. The sensibility of 1,4x10{sup -6}M for U(IV) with 0,8% of precision, 1,6x10{sup -6}M for hydrazine with 0,8% of precision, 2,3x10{sup -6}M hydrazoic acid with 0,9% of precision and 2,5x10{sup -6}M for hydroxylamine with 0,8% of precision were achieved. The interference studies have shown that each reducing agent can be determined in the presence of each other without any interference. Uranium(VI) and plutonium have also shown no interference in these analysis. The established methods were adapted to run inside glove-boxes by using an optical fiber colorimetry and applied to process control of the CELESTE I installation. The results pointed out that the methods are reliable and safety in order to provide just-in-time information about process conditions. (author)

  17. X-Ray Fluorescence Spectrometry. II Determination of Uranium in ores; Espectrometria de fluorescencia de Rayos X. II-Aplicacion a la determinacion de uranio en minerales

    Energy Technology Data Exchange (ETDEWEB)

    Bermudez Polonio, J; Crus Castillo, F. de la; Fernandez Cellini, R

    1961-07-01

    A method of analysis of uranium in ores by X-ray spectrometry was developed, using the internal standard technique. Strontium was found to be the most suitable internal standard for general use. A Norelco Philips X-ray fluorescent spectrometer was used in this work, equipped with a lithium fluoride crystal acting as a diffraction grating analyzer. The intensity of the uranium-L {alpha}{sub 1} spectral line is calculated and related to corresponding strontium-K{sub {alpha}} spectral line, both detected with a Scintillation Counter. (Author) 31 refs.

  18. Scale-up of mixer-settler for uranium extraction; Determinacao das relacoes de `scale-up` em misturador-decantador tipo caixa utilizado na extracao de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Santana, A.O. de

    1990-05-01

    The aim of this work was to obtain scale-up relations for a box type mixer-settler used in uranium extraction process for chloridric leaches. Three box type units with different sizes and with the same geometry were used for scale-up of the mixer. The correlation between extraction rate and specific power input, D/T ratio (stirrer diameter/mixer length) and residence time were experimentally obtained. The results showed that the extraction increases with power input for a constant value of D/T equal to 1/3, remaining however independent from mixer sizes for a specific value of power input. This behavior was observed for power input values ranging from 100 to 750 w/m{sup 9}. (author). 23 refs, 22 figs, 23 tabs.

  19. ISO 14006. Experiencias previas de estudios de arquitectura que han adoptado el estándar de ecodiseño UNE 150301:2003

    Directory of Open Access Journals (Sweden)

    Arana-Landín, G.

    2012-09-01

    Full Text Available This paper aims to analyze the pioneer UNE 150301 standard, as well as its adoption process and its practical results in the sector of architecture studios. First, the structure, the aim and the scope of norm UNE 150301 have been analysed. Second, the standard's implementation has been examined, concluding that 73% of the companies that have obtained the certificate are architecture studios. A case study has therefore been carried out with the participation of five architecture studios pioneers. These experiences have let us know the main aspects and difficulties of the process. In conclusion, the adoption of the standard UNE 150301 can be a helpful tool in order to reduce the environmental impact of the products and obtain some competitive advantages such as cost reduction, improvement in energy efficiency of the product and a better adaptation to acts and regulations.

    En este artículo se analiza la experiencia de implantación de la norma UNE 150301 de ecodiseño en el sector de los estudios de arquitectura. Tras el examen de la estructura de norma UNE 150301, de sus objetivos y de su alcance, se analiza su difusión, destacándose que el 73% de las empresas certificadas en España son estudios de arquitectura. A continuación se estudia el proceso de implantación real, mediante el estudio de caso que lo analiza en cinco estudios de arquitectura. El estudio realizado permite conocer de primera mano las principales claves y dificultades del proceso de implantación del estándar, así como los resultados obtenidos, entre los que destaca una reducción del impacto ambiental. Se constata, en suma, que la norma UNE 150301 es una herramienta que puede proporcionar ventajas competitivas interesantes a las empresas del sector de los estudios de arquitectura.

  20. La necesaria comprensión previa de la realidad constructiva del monumento: el caso singular de la Cripta de la Colonia Güell

    Directory of Open Access Journals (Sweden)

    Casals Balagué, Albert

    1993-10-01

    Full Text Available The Crypt of the Güell Colony is a building of a unique importance in the history of architecture although it is only a part of the church which Antoni Gaudí designed for Eusebio Güell. It owes its fame to the perfect conjunction of the expressive will of the author and the demands of statics it represents. This conjunction was achieved by using the design method based on the properties of funicular lines. This is where the great paradox of the Crypt lies: it is arable in spite of being a part of a whole which, logically thinking, should have reached the balance only after being completed, which, consequentially, casts doubt on whether the building would have been stable had it been finished. This article presents the conclusions of a study which was carried out by the authors who allow this paradox to be understood. The study is a part of another complete physical-constructive analysis which compiles the necessary information for the restoration of the monument ordered by the Servei de Patrimoni Arquitectonic Local de la Diputación de Barcelona under the direction of the architec Antoni González. The methods for building modelling used in the study range from graphic statics, which does not explain the paradox, to the finite element method, which contributes a sufficient number of facts for such on explanation. The finally developed model is a powerful and reliable tool which allows us to forsee the effects of any modification of the present state of the monument, including those produced by its hypothetical completion.

    La Cripta de la Colonia Güell es un edificio de similar relevancia en la historia de la arquitectura, a pesar de tratarse sólo de una parte de la iglesia que proyectó Antoni Gaudí para don Eusebio Güell. Debe su notoriedad a la conjunción perfecta que en ella se dan entre la voluntad expresiva de su autor y los requerimientos de la estática, conjunción que se consiguió gracias al método de proyecto basado en las propiedades de las líneas funiculares. Y en ello reside la gran paradoja que envuelve a la cripta: ser estable a pesar de ser una parte de un conjunto que, en buena lógica, debería haber alcanzado el equilibrio al haberse completado, lo que, en consecuencia, pone en duda la estabilidad de éste si se hubiera finalizado. El estudio realizado por los autores que permite entender esta paradoja ha utilizado como métodos para modelizar el edificio desde la estática gráfica, que no la explica hasta el método de los elementos finitos, que aporta suficientes datos para comprenderla. El modelo desarrollado finalmente es una herramienta potente y fiable que permite prever los efectos de cualquier modificación del estado actual del monumento, incluidos los producidos por su hipotética finalización.

  1. Limpieza del vidrio por erosión iónica, previa a la deposición del recubrimiento decorativo

    Directory of Open Access Journals (Sweden)

    Vershinin, N.

    2000-10-01

    Full Text Available Sputter cleaning is the most reliable way for the pre-treatment of substrates before the deposition of coatings with the aid of magnetron sputtering or vacuum arc deposition. In this work, a large-aperture Hall current accelerator was developed for the sputter cleaning of large-area glasses, metals and plastics sheets. The main advantage of the Hall current accelerator is the possibility to use reactive gases. The Hall accelerator developed is able to work with argon, oxygen, nitrogen and carbon dioxide. The accelerator has the form of a very elongated loop with a large aperture (1400 mm in the vertical direction. The maximum power of the Hall current accelerator is 10 kW. The current-voltage characteristic measured for argon is presented. It allows one to optimise the regime of sputter cleaning by finding the maximum power value at a stable discharge.

    La erosión iónica es el método más eficaz para la eliminación de la capa superficial de los substratos en su fase de preparación para la deposición de recubrimientos en vacío. En el presente trabajo se describe la construcción y características de un acelerador Hall de la corriente eléctrica de abertura larga, diseñado para la limpieza, mediante erosión iónica, de superficies de substratos de vidrio, metal y plástico en forma de láminas con área extensa. Una de las ventajas del acelerador Hall es la posibilidad de uso de gases reactivos. El acelerador aquí descrito es capaz de trabajar con argón, oxígeno, nitrógeno y dióxido de carbono. Este acelerador tiene una forma de bucle muy alargado y, por tanto, dispone de una abertura larga (1400 mm en vertical. La potencia máxima del acelerador es de 10 kW. Se presenta la característica corriente-tensión del acelerador en atmósfera de argón que permite optimizar el régimen de limpieza por erosión, encontrando el máximo de potencia para la descarga estable.

  2. EL AGOTAMIENTO DE LA VIA ADMINISTRATIVA PREVIA EN EL DERECHO CHILENO. EL ARTICULO 54 DE LA LEY N°19.880, Y EL REGIMEN EN LOS PROCEDIMIENTOS ESPECIALES

    OpenAIRE

    BETANCOURT SOLAR, RICARDO ALONSO; BETANCOURT SOLAR, RICARDO ALONSO

    2012-01-01

    El presente trabajo pretende determinar si existe en Chile una regla general sobre la obligatoriedad o no de agotar la vía administrativa, previo a intentar la acción contenciosa administrativa, lo que nos llevará a analizar las reglas contenidas en el artículo 54 de la ley N° 19.880, y luego revisar lo que ocurre en algunos de los innumerables procedimientos especiales. Antes de ello, ciertamente, es necesario efectuar ciertas precisiones a la institución del agotamiento de la vía prev...

  3. Glaucoma maligno en paciente con cirugía previa de catarata traumática e implante valvular: reporte de caso

    Directory of Open Access Journals (Sweden)

    Juan Carlos Serna-Ojeda

    2015-07-01

    Full Text Available El glaucoma maligno es un glaucoma secundario asociado con un bloqueo ciliar y dirección equivocada del flujo del humor acuoso. Se presenta el caso de un paciente masculino de 19 años con antecedente de explosión de filtro metálico en ojo derecho. Se encuentra con una presión intraocular de 52 mmHg y cristalino luxado a cámara anterior. Se inicia terapia máxima para glaucoma y se realiza facoemulsificación con posterior colocación de válvula de Ahmed, y 3 semanas después de la cirugía presenta hallazgos clínicos compatibles con glaucoma maligno. Se presenta el seguimiento del paciente y los estudios de imagen indicados

  4. EFECTO ANALGESICO DEL LASER EN PUNTOS ASHI, EN PACIENTES GERIATRICOS CON GONOARTROSIS, EVALUANDO EL DOLOR CON ESCALA VISUAL ANALOGA. PREVIA APERTURA DE CANALES TENDINOMUSCULARES

    OpenAIRE

    LUENGAS CRUCES, SARA ELIZABETH

    2010-01-01

    LA GONOARTROSIS, ES EL PADECIMIENTO MAS FRECUENTE EN LA PRACTICA CLINICA REUMATOLOGICA. TIENE UNA PREVALENCIA ALTA EN PERSONAS MAYORES DE 30 ANOS, POR LO QUE YA CONSTITUYE UN PROBLEMA DE SALUD Y FORMA PARTE DE UNA PANDEMIA DE ENFERMEDADES CRONICO-DEGENERATIVAS (VAZQUEZ MARTINEZ F Y ORTIZ ALVAREZ O. LA INVESTIGACION LATINOAMERICANA SOBRE OSTEOARTROSIS. GAC.MED. VOL. IV,1990 PG. 131)EN LOS REPORTES ESTADISTICOS DEL INEGI Y EN LOS SERVICIOS DE CONSULTA EXTERNA DE ESPECIALIDADES DEL IMSS LA PREVA...

  5. ¿Se están alcanzando las metas en el perfil lipídico de personas con enfermedad coronaria previa?

    Directory of Open Access Journals (Sweden)

    Alonso Merchán, MD

    2011-08-01

    Conclusiones: después de nueve años de la publicación de las guías del NCEP-ATPIII y de las recomendaciones posteriores sobre las metas del perfil lipídico en pacientes con enfermedad coronaria y a pesar de la divulgación de las mismas a través de conferencias, congresos y publicaciones, estas metas las cumple un porcentaje bajo de pacientes, tal como lo demuestra este estudio observacional en sujetos hospitalizados por causas diferentes a la enfermedad coronaria pero con este antecedente. Una de las explicaciones para este pobre resultado es el uso de lovastatina, estatina de baja efectividad para reducir el cLDL. Se analizan otras posibles causas y se hacen propuestas para lograr los objetivos.

  6. Introducción a los Materiales de Construcción: Revisión de experiencia previa y nuevas propuestas metodológicas

    OpenAIRE

    Chinchón Yepes, Servando; Prado Govea, Raúl Hugo; Chinchón Payá, Servando; Piedecausa García, Beatriz

    2015-01-01

    El Curso Académico 2010-2011 comenzaron los estudios de Grado de Ingeniería de la Edificación en la Universidad de Alicante. Cuatro años después, la Titulación ha retomado de nuevo el nombre de Grado en Arquitectura Técnica sin que haya habido modificación en las enseñanzas. Después de solo cuatro años, la asignatura de Introducción a los Materiales de Construcción no presenta un recorrido tan extenso como para hacer una evaluación exhaustiva. Pero sí lo suficiente como para revisar algunos t...

  7. The Uterine Sandwich Method for Placenta Previa Accreta in Mullerian Anomaly: Combining the B-Lynch Compression Suture and an Intrauterine Gauze Tampon

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    Mustafa Kaplanoğlu

    2013-01-01

    Full Text Available Mullerian duct anomalies may cause obstetric complications, such as postpartum hemorrhage (PPH and placental adhesion anomalies. Uterine compression suture may be useful for controlling PPH (especially atony. In recent studies, uterine compression sutures have been used in placenta accreta. We report a case of PPH, a placenta accreta accompanying a large septae, treated with B-Lynch suture and intrauterine gauze tampon.

  8. Resistencia transmitida del virus de la inmunodeficiencia humana en pacientes sin exposición previa a tratamiento antirretroviral, Cali, Colombia, 2010

    Directory of Open Access Journals (Sweden)

    Pablo Galindo-Orrego

    Full Text Available Introducción: En Colombia, existe poca información publicada sobre farmacorresistencia transmitida en el virus de inmunodeficiencia humana (VIH, y actualmente, las pruebas genotípicas de resistencia no son recomendadas por las guías colombianas para pacientes nunca expuestos ( naïve a terapia antirretroviral (TAR. Se condujo un estudio para determinar la frecuencia de resistencias transmitidas en pacientes naïve a TAR, quienes fueron atendidos en una clínica especializada en VIH/síndrome de inmunodeficiencia adquirida en Cali, Colombia. Metodología: Se realizó un estudio transversal en 152 pacientes adultos elegibles, con infección confirmada por VIH, naïve a TAR, con pruebas genotípicas de resistencia disponibles, y que accedieron a participar. El período de reclutamiento fue de 2008 a 2010. Las mutaciones de resistencias incluidas en el análisis fueron las definidas por la Organización Mundial de la Salud 2009 e International AIDS Society-USA 2010. Adicionalmente, se recolectó información sociodemográfica y condiciones relacionadas con el VIH. Resultados: La edad promedio fue 32 ± 10,2 años, 76% fueron hombres. La frecuencia de resistencia primaria fue de 6,6% (según la lista de Bennett-Organización Mundial de la Salud 2009, pero se encontró algún nivel de resistencia hasta en un 11,8% de los casos (al considerar mutaciones de la lista International AIDS Society-USA 2010. Las mutaciones más comunes fueron K103N/S (2%, F77L (2% y M46L (2%. Mutaciones a los inhibidores no nucleosídicos de transcriptasa reversa fueron encontradas en 5,3%, mutaciones a los inhibidores no nucleosídicos de transcriptasa reversa en 3,9% y mutaciones a inhibidor de proteasa en 2% de las secuencias. El único factor relacionado con la resistencia primaria fue la duración de la infección por VIH. Conclusiones: La frecuencia de resistencia transmitida es similar a la encontrada en estudios previos en Colombia y en otros países con amplio uso de antirretrovirales, y está por encima del umbral sobre el cual sería costo-efectivo incluir el estudio genotípico de resistencias como test de rutina antes de la iniciación de la TAR, especialmente en pacientes con infección por VIH de menos de un año de duración.

  9. La cultura de la información como institución previa a la sociedad de la información

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    Alfons Cornella Solans

    2015-02-01

    Las economías occidentales se están convirtiendo en economías de la información. Quizás sea el caso norteamericano el más claro exponente del proceso de informacionalización de las economías. El discurso tradicional señala a la inversión en tecnologías de la información como principal causa de este proceso. Sin embargo, puede que existan factores culturales, como por ejemplo la existencia de una cultura de la información desarrollada, que expliquen porque la evolución hacia la sociedad de la información se produce más aceleradamente en algunos países. Conseguir una economía de la información sería, pues, distinto de alcanzar la sociedad de la información. La cultura informacional de los ciudadanos sería un requisito necesario para conseguir este último objetivo. Y la cultura de la información no puede alcanzarse simplemente mediante el establecimiento de políticas y acciones, sino que requiere de una evolución del orden espontáneo. La cultura de la información se constituiría, pues, como una institución necesaria en las sociedades modernas.

  10. Eficiencia de la implantación del cultivo de maíz (Zea mays l.) en secuencias de siembra directa y labranza previa

    OpenAIRE

    Soza, Eduardo Leonardo; Tourn, Mario César; Agnes, Diego Wilfredo; Botta, Guido Fernando

    2008-01-01

    p.11-17 El cultivo de maíz requiere una correcta implantación para la obtención de un buen rendimiento y la siembra directa es una técnica que no siempre está unida al cumplimiento de este objetivo, siendo la sembradora, su alistamiento y regulación, una herramienta clave para ese propósito. En siembra directa la cuchilla labrasurco y surcador doble disco generan mínima remoción de suelo, obteniéndose emergencias inferiores a la siembra convencional. Utilizando una misma máquina sembradora...

  11. El Derecho a la Consulta Previa de los Pueblos Indígenas y Ciudadanía Multicultural en Brasil

    Directory of Open Access Journals (Sweden)

    Germana Aguiar Ribeiro do Nascimento

    2016-06-01

    Full Text Available Desde finales del siglo XX, las reclamaciones de los pueblos indígenas se tornaran frequentes, lo que contribuyó para los cambios legislativos. En efecto, derechos indígenas son ahora garantizados, es el caso del derecho a consulta. El objetivo de este artículo es analizar el acceso de este derecho, observando en qué medida está protegido y su relación con la construcción de una ciudadanía multicultural. La investigación es de carácter cualitativo: son analizados la legislación y jurisprudencia. Se puede observar que a pesar de la legislación, él no es respectado, lo que impide la realización de una ciudadanía multicultural en Brasil.

  12. Desarrollo de un nuevo modelo de Aspergilosis Pulmonar en rata consideraciones previas, estudio comparativo y aplicaciones al diagnóstico de la enfermedad

    OpenAIRE

    Caballero de Toro, Jesús

    2005-01-01

    Aspergilosis incluye una gran cantidad de enfermedades, incluida la Aspergilosis Invasora. El objetivo de esta tesis es el estudio de la Aspergilosis invasora en humanos. En primer lugar se evalúan los perfiles proteicos de A. fumigatus crecidos en diferentes medios y su capacidad antigénica. Posteriormente se realiza una evaluación de la capacidad de infección de A. fumigatus en modelos animales en ratones y ratas. Se desarrolla un nuevo modelo de infección transtorácia con hifas. Finalmente...

  13. Plan de mejoramiento financiero previa realización de auditoría de estados financieros de la empresa Tobamac S.A., ejercicio fiscal 2010

    OpenAIRE

    León Llanos, Andrés Paúl

    2012-01-01

    El presente trabajo de investigación en la empresa Tobamac S.A., tiene por objetivo sugerir recomendaciones respecto 4 temas influyentes en la situación financiera de la compañía consideradas críticas por la administración: Liquidez, impacto de los gastos no deducibles en el cálculo del Impuesto a la renta causado, apreciación de los estados financieros y evaluaciones de centros de costos. Previo a realizar el análisis, se ejecuta un trabajo de Auditoría a Estados Financieros del año 2010 con...

  14. Uranium prospecting program: memorandum of request United Nations Assistance Rotatory Fund for Naturals resources in Uranium Prospecting; Programa prospeccion Uranio: memorando de solicitud de asistencia al fondo Rotatorio de Naciones Unidas para el estudio de los Recursos Naturales para la prospeccion de Uranio

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1976-07-01

    The Uruguayan government required assistance to Unit Nations funds with the aim of studies the Natural resources in Uranium prospecting, their antecedent, actual and projected works, equipment and end considerations.

  15. Critical analysis of the management of waste system originated at the uranium mining and processing. A case study of the Concentrated Unit of Uranium - INB; Analise critica do sistema de gerenciamento de rejeitos provenientes de mineracao e beneficiamento de uranio. Um estudo de caso da Unidade de Concentrado de Uranio/INB

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Valeska Peres de

    2005-07-01

    The uranium world market faced a depreciation of this commodity during the last decades. Recently, decreases in the secondary supply (represented by highly enriched uranium - HEU - stocks detained by the former Soviet Union) turned out the market dependent upon primary supply again. In order to cope with this changing demands and market conditions, new uranium mining/milling projects must start operation, or at least, former uranium production plants must be improved. Environmental questions have been and certainly will continue to be a determinant factor concerning the operational feasibility of these facilities. Mining/milling activities have the potential to cause risks to the human health and to the environment. In case of uranium projects, radiological impacts shall also be taken into consideration. Amongst the most relevant environmental aspects associated with the operation of a uranium project, generated wastes are usually of major concern and deserve appropriate management strategies. As a result the objective of the present work was to examine the waste management system of the Brazilian uranium production unity located at the municipality of Caetite, northeast region of the country. An open pit mine and a milling facility compose this unit. The extraction method employed is acid heap leach (using H{sub 2}SO{sub 4}). It could be assessed that the overall conceptual management strategy is in agreement with the practices adopted worldwide. Atmospheric impacts, caused by the emissions of radon and aerosols must be investigated in more details. Mathematical simulation revealed that no significant impact in groundwater is expected due to mobilization and transport of radionuclides from the milling wastes. However, the impacts of drainage water, accumulated in the open pit, into groundwater cannot be discarded yet. Screening techniques were applied to assess the potential contribution of the leached ore piles as a {sup 226}Ra source of pollution. Our results did not allow to exclude these sources from further investigations. Optimization in the drainage water management strategy shall also be put in place and chemical treatment of these waters, prior to their release into the environment, shall be considered. Finally, it is advisable to introduce an Environmental Management System (EMS) for the whole facility in order to reach a better environmental performance. (author)

  16. Manufacture of uranium compounds for research reactors fuel elements. Participation of the UCPP (Uranium compound production plant) in the Egyptian project; Elaboracion de compuestos de uranio para ser utilizados en elementos combustibles de reactores de investigacion. Participacion de la planta de fabricacion de compuestos de uranio (PFPU) en el proyecto Egipto

    Energy Technology Data Exchange (ETDEWEB)

    Boero, Norma L; Cinat, Enrique; Yorio, Daniel; Cincotta, Daniel; Ramella, Jose L; Bruno, Hernan R; Camacho, Esteban F; Pertossi, Fernando; Panunzio, Leonardo D; Fernandez, Carlos A; Sassone, Ariel [Comision Nacional de Energia Atomica, General San Martin (Argentina). Dept. de Combustibles Nucleares

    1999-07-01

    UCPP is an international qualified supplier of U{sub 3}O{sub 8} with up to 20 % enrichment in U-235. The characteristics of this powder are those specified for fuel plates manufacture for test reactors. This paper describes the works performed in the plant since its beginning, emphasising those undertaken during the last years. The transference of U{sub 3}O{sub 8} manufacturing technology to INVAP SE, the enterprise that installed a plant of similar characteristics in the Arabian Republic of Egypt, is especially described. (author)

  17. Acid drainages of the pyritic sterile from the Pocos de Caldas uranium mine: environmental interpretation and implications; Drenagens acidas do esteril piritoso da mina de uranio de Pocos de Caldas: interpretacao e implicacoes ambientais

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Vicente Paulo de

    1995-12-01

    Considering the planned closure of the first uranium mine and milling plant operating in Brazil, located in the Pocos de Caldas Plateau, in the State of Minas Gerais, in the next two years, there is the need to obtain basic information for its decommissioning. Special attention has been directed to the following critical areas: open pit, tailing, dam and waste rock piles, because these are the main sources of acid drainage generation. These waters cannot be allowed to flow in the external environment because in addition to sulphuric acid, there is a number of elements in concentration above those allowed by regulations. Among the waste piles (bota-foras BF) two of them BF-4 and BF-8, are in a process of acid generation, thus requiring more attention. The objective of this work was to simulate at the laboratory scale the oxidation and the reduction zones of BF-4. The experiments were conducted in acrylic columns, where the waste sample was kept under aerated and saturated conditions, in different columns. The control of the chemical (solubilized chemical species), physico-chemical (redox potential, pH, conductivity) and biological (bacterial activity) parameters has been carried out on the acid solutions generated by the chemical and biological reactions that occur at the waste. Although the results refer to a four month period, some relevant points can be highlighted, which will serve as a basis for further research. The mineralogical characterization identified the existence of other sulphides associated to pyrite with lower oxidation potential than the latter. The results obtained with the biological characterization for the two conditions studied revealed that the bacterial activity is more intense in the region in contact with air, than in saturated region. (author) 30 refs., 29 figs., 8 tabs.

  18. Evaluation of iron phosphate (III) as reactive material for removal of uranium in water; Evaluacion del fosfato de hierro (III) como material reactivo para la remocion de uranio en agua

    Energy Technology Data Exchange (ETDEWEB)

    Solis M, L

    2004-02-01

    The levels of toxic metals in the atmosphere are topic of growing interest. This has provoked that the legislation is stricter, for that that the industry and centers of investigation has worried and busy of to look for and to develop more effective methods for the control of the contamination, with the purpose of being inside this levels. The phosphate compounds are being investigated for the removal of pollutants of the water and soil. In this work, it was synthesized to the ferric phosphate in a simple way in the laboratory, obtaining high grade of purity and yield. The characterization of this product was in a physicochemical way and of surface, through diverse analytical techniques. In the first place, the physicochemical characterization was carried out for Scanning Electron Microscopy of High Vacuum, X-ray diffraction, Infrared Spectroscopy with Fourier Transform, and Thermal gravimetric Analysis, the surface characterization was carried out for analysis of the surface area, determination of the isoelectric point by potentiometric and of mass titrations. The previous techniques allowed to identify the ferric phosphate synthesized as a compound amorphous beige color, with a relationship of atoms Fe:1, P:1, O:4, which showed connections P-O and went stable to changes of temperature. The surface area it was of 21 g / m{sup 2}, the isoelectric point corresponded to a p H of 1.5, which coincided so much by potentiometric like by mass titration. The number of active sites was of 106 sites /nm{sup 2}. After the characterization of the ferric phosphate the compound was evaluated as reactive material for the removal of uranyl ions through sorption tests. The kinetics of hydration showed that the product requires of 24 hours to saturate the sites capable of to be hydrated. The sorption kinetics required 22 hours of contact to reach the maximum sorption of uranyl ions for the ferric phosphate. The sorption isotherms showed that not significant difference exists when using 0.05, 0.1, 0.15 and 0.2 g of ferric phosphate, for that 0.1 g of material was used. The isotherms were carried out in function of the p H of the uranyl solutions and of the mass of the ferric phosphate where is observed that to p H 3.5-5 the percentage of removal is the highest reaching bigger values to 90%. Finally the data of the sorption of uranium was adjusted to the pattern of Langmuir. (Author)

  19. Determination of the ratio between phosphorus and uranium in surface waters selected in the State of Mexico; Determinacion de la relacion entre fosforo y uranio en cuerpos de agua seleccionados en el Estado de Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Ordonez R, E

    2001-07-01

    The agricultural regions lately, they have suffered a severe contamination for the big ones quantities of chemical fertilizers and of pesticides applied to improve their production and quality, increasing these in areas with temperatures but you lower that the average. For the importance of the physicochemical processes that they are made in the waters to settle down surface near to agricultural fields, the physicochemical characteristics were analysed of these waters to determine the contributions that they carry out the phosphate fertilizers that are carried by the escorrentia toward the borders and to make a pursuit of their variability during an agricultural cycle, in times of the summertime and of rains, as well as to observe the effect of the depth in these physicochemical properties. Its were sampling three borders and a spring that it served of white, all them located in the suburbs of the Xinantecatl (Nevado de Toluca), municipality of Zinacantepec, State of Mexico, area with the temperatures but drops registered in the region. They were carried out samplings in the first days of the months of April, July and November. The points of those sampled borders were the influent, the effluent and 3 different depths (lm, 3m and 5m). where was not possible sampling all the points, its were sampling only the one influent and the effluent. The selected physicochemical parameters were the temperature, the pH, the conductivity electric and the one oxygenates dissolved This determination in situ you carries out with a team portable of type Check-Mate, of interchangeable electrodes. The certain anions they were phosphates, nitrates, sulfates and bicarbonates; the measurement of the concentration of anions, one carries out for ultraviolet-visible light spectroscopy and titration. The cations analysed they were sodium, potassium, iron, calcium and magnesium. The cations concentration was determined by atomic absorption spectroscopy. The determination of the uranium concentration it was made by means of neutron activation analysis. The physicochemical parameters diminished of value in the temporary analysis, as long as those anions and the cations didn't show a behavior defined in this same analysis, while in the analysis in depth these parameters presented minimum changes. In the modelling one for computer packages, the results of the speciation analysis chemistry, by means of the Medusa program, they revealed that the species of uranium in solution but abundant they were phosphate uranyl monoacid, tris uranyl carbonate and bis uranyl carbonate and, in smaller proportion, the species of aqueous uranyl hydroxide. The characterization of waters for the program GWW gave as a result that the facies but representative it was the bicarbonate magnesia. In the study of the quality of the one it dilutes with ends of agricultural watering, they were classified as capable for this purpose. The analysis statistical one carries out with base in the correlation coefficient whose value among the uranium and the match is moderated in three sampling points. (Author)

  20. Metallogenetic modeling for uranium exploration in rocks of the Abaira-Jussiape Anticlinal nucleus, Chapada Diamantina, Bahia; Modelagem metalogenetica para prospeccao de uranio nas rochas do nucleo da Anticlinal Abaira-Jussiape, Chapada Diamantina, Bahia

    Energy Technology Data Exchange (ETDEWEB)

    Santana, Jocilene dos Santos; Cruz, Simone Cerqueira Pereira; Barbosa, Johildo Salomao Figueiredo [Universidade Federal da Bahia (PPGG/UFBA), Salvador, BA (Brazil); Abram, Maisa Bastos; Martins, Adriano Alberto Marques, E-mail: jocilenesanttana@yahoo.com.br, E-mail: simonecruzufba@gmail.com, E-mail: johildo@cpgg.ufba.br, E-mail: maisa.abram@cprm.gov.br, E-mail: adriano1952@gmail.com [Companhia de Pesquisas de Recursos Minerais (CPRM), Salvador, BA (Brazil). Superintendencia Regional de Salvador. Servico Geologico do Brasil

    2011-06-15

    The NNW-SSE-trending Abaira-Jussiape Anticlinal is an antiformal culmination of folding and shearing in the Paramirim Corridor of the Western Chapada Diamantina. In its core paleoproterozoic, mylonitized Caraguatai Suite, tonalites-granodiorites, alkali-feldspar granites, syenites to quartz-syenites and Jussiape Suite granites crop out. Compressional and distensional stresses mark the structural geology of the area. The compressional structures are related to two distinct deformation phases, named D1a and D1b. The main compressional phase is ductile D1a, which is related to the nucleation of dextral to dextral-reverse shearing zones. Deformation and syn-D1a recrystallization involving plagioclase and the K-feldspar suggest deformation temperature conditions above 550 deg C. The following phase D2 is of ductilebrittle nature and culminates in reverse shearing zones. The distensional structures correspond to the D3 phase and are represented by frontal shear zones with normal movement. The petrographic study helped identify a pre-D1a hydrothermal alteration process related to albitization and potassification, syn-D1 oxidation process, and hydration and saussuritization related to phases D2 and D3. The integration of lithological, petrographic, structural and geophysical data by means of the logic Fuzzy, plus the existing information regarding structural and lithologic controls of the known uranium mineralization in the Paramirim Corridor, led us to identify two promising areas for radioactive element exploration in the nucleus of Abaira-Jussiape Anticlinal. (author)

  1. The biography of Uranium: from the Proto-solar cloud to the beginning of the oxygenic atmosphere; La biografia del Uranio. Desde la nube protosolar hast el comienzo de la atmosfera oxigenica

    Energy Technology Data Exchange (ETDEWEB)

    Garzon Ruiperez, L.; Cavero Cavero, A.

    2000-07-01

    The geo-chemical properties of uranium and its materials have allowed us to consistently describe this element's characteristics in the evolution of matter from the proto-solar nebula to the formation and subsequent evolution of the Earth. The formation of the most primitive deposits is considered , and it is inferred that they were of a detrital nature. The ionizing radiations emitted by these deposits and the existence of critical episodes in them have been considered. The low concentration of O{sub 2} until some 2.4 Ga ago was the reason why uranium deposits were not widespread and why their typology and the typology of their minerals were not very diversified. Uranium evolution, deposits, minerals, radiation, criticality. (Author)

  2. Evaluation of cell number and DNA content in mouse embryos cultivated with uranium; Evaluacion del numero de celulas y el contenido de DNA en embriones murinos cultivados con uranio

    Energy Technology Data Exchange (ETDEWEB)

    Kundt, Mirian S; Cabrini, Romulo L [Comision Nacional de Energia Atomica, General San Martin (Argentina). Dept. de Radiobiologia

    2000-07-01

    The evaluation of the degree of development, the number of cells and the DNA content, were used to evaluate the embryotoxicity of uranium. Embryos at a one cell stage were cultured with uranyl nitrate hexahydrate (UN) at a final concentration of uranium (U) of 26, 52 and 104 {mu}gU/ml. At 24 hs of culture, the embryos at the 2 cell stage, were put in new wells with the same concentrations of U as the previous day, until the end of the period of incubation at 72 hs. At 72 hs of culture, 87% of the original one cell embryos were at morula stage, and in those cultivated with uranium, the percentage decreased significantly to 77; 63.24 and 40.79% respectively for the different U concentrations. Those embryos that exhibited a normal morphology, were selected and fixed on slides. The number of cells per embryo was evaluated in Giemsa stained preparations. The DNA content was evaluated cytophotometrically in Feulgen stained nuclei. The number of cells decreased significantly from 20,3 {+-} 5.6 in the control to 19 {+-} 6; 14 {+-} 3 and 13.9 {+-} 5.6 for the different concentrations. All the embryos evaluated showed one easy recognizable polar body, which was used a haploid indicator (n). The content of DNA was measured in a total of 20 control embryos and 16 embryos cultivated with UN. In control embryos, 92,7% of the nuclei presented a normal ploidy from 2n to 4n, 2,9% nuclei were hypoploid and 4,4% were hyperploid. The percentage of hypoploid nuclei rose in a dose-dependent fashion to 3.45; 44.45 and 50.34% respectively for the embryos cultured at the different U concentrations. The results indicate that U is embryotoxic, that its effects are dose dependent at the concentrations used in this study and that even those embryos that show a normal morphology, can be genetically affected. We show that the model employed is extremely sensitive. It is possible to use the preimplantation embryos, as a model to test the effect of possibly mutagenic agents of the nuclear industry. (author)

  3. Design of an equilibrium nucleus of a BWR type reactor based in a Thorium-Uranium fuel; Diseno de un nucleo de equilibrio de un reactor tipo BWR basado en un combustible de Torio-Uranio

    Energy Technology Data Exchange (ETDEWEB)

    Francois, J.L.; Nunez C, A. [Laboratorio de Analisis en Ingenieria de Reactores Nucleares, Facultad de Ingenieria-UNAM, Paseo Cuauhnahuac 8532, Jiutepec, Morelos (Mexico)

    2003-07-01

    In this work the design of the reactor nucleus of boiling water using fuel of thorium-uranium is presented. Starting from an integral concept based in a type cover-seed assemble is carried out the design of an equilibrium reload for the nucleus of a reactor like that of the Laguna Verde Central and its are analyzed some of the main design variables like the cycle length, the reload fraction, the burnt fuel, the vacuum distribution, the generation of lineal heat, the margin of shutdown, as well as a first estimation of the fuel cost. The results show that it is feasible to obtain an equilibrium reload, comparable to those that are carried out in the Laguna Verde reactors, with a good behavior of those analyzed variables. The cost of the equilibrium reload designed with the thorium-uranium fuel is approximately 2% high that the uranium reload producing the same energy. It is concluded that it is convenient to include burnable poisons, type gadolinium, in the fuel with the end of improving the reload design, the fuel costs and the margin of shutdown. (Author)

  4. Uranium accumulation in Brassica rapa L. and effect of citric acid and humic acids as chelating agents; Acumulacion de uranio en Brassica rapa L. y efecto del acido citrico y acidos humicos como agentes quelantes

    Energy Technology Data Exchange (ETDEWEB)

    Lopez del R, H.; Perez C, G. A.; Davila R, J. I.; Mireles G, F. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98060 Zacatecas, Zac. (Mexico); Rodriguez H, G., E-mail: hlopezdelrio@hotmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Agronomia, Carretera Zacatecas-Guadalajara Km 15.5, Cieneguillas, Zacatecas (Mexico)

    2016-09-15

    Phyto extraction is a technique that makes use of plants for the remediation of soils contaminated with heavy metals. In this study the uranium incorporation in the Brassica rapa L. species was evaluated, in artificially contaminated inert soils with 40 mg U/kg, and the effect of adding of the natural chelating agents citric acid and humic acids in the accumulation of uranium was analyzed. Soil free of organic matter and biologically inert was obtained by controlled calcination s of natural soil. Cultures in the prepared soil consisted of five growth treatments: 1) cultivation without uranium or additives; 2) cultivation in the uranium presence; 3) cultivation with uranium and citric acid (2 g/kg); 4) cultivation with uranium and humic acids (10 g/kg); 5) uranium cultivation and combination of citric and humic acids at the same concentrations. There was no adverse effect on plant growth with the presence of uranium at the given concentration. Regarding the controls, the total biomass in the presence of uranium was slightly higher, while the addition of humic acids significantly stimulated the production of biomass with respect to the citric acid. The combined action of organic acids produced the highest amount of biomass. The efficiency of phyto extraction followed the order Humic acids (301 μg U/g) > Non-assisted (224 μg U/g) >> Citric acid + Humic acids (68 μg U/g) > Citric acid (59 μg U/g). The values of uranium concentration in the total biomass show that the species Brassica rapa L. has the capacity of phyto extraction of uranium in contaminated soils. The addition of humic acids increases the uranium extraction while the addition of citric acid disadvantages it. (Author)

  5. Determination of rare earth and uranium in reference biological materials certified by the method of neutron activation analysis; Determinacao de terras raras e de uranio em materiais biologicos de referencia certificados pelo metodo de analise por ativacao com neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Lais H.P.; Saiki, Mitiko, E-mail: laispaciulli@gmail.com, E-mail: mitiko@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    The objective of this study was to evaluate the precision and accuracy of the determinations of Sc, La, Ce, Nd, Sm, Eu, Tb, Yb, Lu and U in certified reference materials (CRMs). To solve the problem of interference from fission products of U in the determination of lanthanides were obtained correction factors for this interference for {sup 140}La, {sup 141}Ce, {sup 143}Ce, {sup 153}Sm and {sup 147}Nd. The experimental procedure of Neutron Activation Analysis consisted of irradiating aliquots of each of the CRMs with synthetic standards of elements under thermal neutron flux of the IEA-R1 nuclear reactor, followed by gamma-ray spectrometry using a high-resolution hyperpurity GE detector. The analyzes of CRMs indicate good accuracy and precision of results, demonstrating the feasibility of applying of established procedure in NAA of elements studied in organic vegetable matrices.

  6. Fluorinated compounds in the uranium conversion process: risk analysis and proposition of pictograms; Os compostos fluorados nos processos da conversao do uranio: analise de riscos e proposicao de pictogramas

    Energy Technology Data Exchange (ETDEWEB)

    Jeronimo, Adroaldo Clovis; Oliveira, Wagner dos Santos, E-mail: acejota18@yahoo.com.br, E-mail: oliveira@feq.unicamp.br [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Fac. de Engenharia Quimica; Aquino, Afonso Rodrigues de, E-mail: araquino@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2012-03-15

    In the process of uranium hexafluoride production there are risks that must be taken into account since the time of completing the project chemist, in its conceptual stage, until to the stage of detailed design and are associated with the handling of chemicals, especially fluoride hydrogen and fluorine. This paper aims to address issues related to the prevention of risks related to industrial safety and health and the environment, considering the different stages of the uranium conversion. Take into account the safety warnings of the plant and, accordingly, make the proposition of pictograms adequate to alert operators of care to be taken during the proposition of pictograms adequate to alert operators of care to be taken during the conduct of these chemical processes. (author)

  7. Event classification related to overflow of solvent containing uranium according to the INES scale (International Nuclear and Radiological Event Scale); Classificacao do evento de transbordamento de solvente contendo uranio segundo a escala INES (International Nuclear and Radiological Event Scale)

    Energy Technology Data Exchange (ETDEWEB)

    Dourado, Eneida R.G.; Assis, Juliana T. de; Lage, Ricardo F., E-mail: cneida@inb.gov.br, E-mail: julianateixeira@inb.gov.br, E-mail: rlage@inb.gov.br [lndustrias Nucleares do Brasil S/A (CLISE.P/INB), Rio de Janeiro, RJ (Brazil). Coordenacao de Licenciamento Nuclear e Ambiental, Saude e Seguranca; Lopes, Karina B., E-mail: karina@inb.gov.br [lndustrias Nucleares do Brasil S/A (CPRAD/INB), Rio de Janeiro, RJ (Brazil). Coordenacao de Protecao Radiologica

    2013-11-01

    This paper aims to frame the event overflow organic solvent rich in uranium, from a decanter of ore beneficiation plant, caused by the fall in the supply of electricity, according to the criteria established by the International Nuclear Event Scale and radiological (INES), facilitating the understanding of the occurrence and communication with the public regarding the radiation safety aspects involved. With the fall of electricity, routine procedures in situations of installation stop were performed, however, due to operational failure, the valve on the transfer line liquor was not closed. Thus, the mixer continued being fed with liquor, that led the consequent leakage of solvent loaded with uranium. It reached the drainage system, and the box of rainwater harvesting of the plant. However, immediately after the detection of the event, corrective actions were initiated and the overflow was contained. Regulatory agencies followed the removal of the solvent and on the results of the analysis of environmental monitoring, found that the event did not provide exposure to workers or any other impact. Therefore, comparing the characteristics of the event and the guidelines proposed by the INES scale, it is concluded that the classification of the event is below scale/level 0, confirming the absence of risk to the local population, workers and the environment.

  8. Identification of uranium signatures in swipe samples on verification of nuclear activities for nuclear safeguards purposes; Identificacao de assinaturas de uranio em amostras de esfregacos (swipe samples) para verificacao de atividades nucleares para fins de salvaguardas nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Pestana, Rafael Cardoso Baptistini

    2013-07-01

    The use of environmental sampling for safeguards purposes, has been applied by the International Atomic Energy Agency–IAEA since 1996 and are routinely used as a complementary measure to strengthen the traditional nuclear safeguards procedures. The aim is verify if the states signatory to the safeguards agreements are not diverging their peaceful nuclear activities for undeclared nuclear activities. This work describes a new protocol of collect and analysis of the swipe samples for identification of nuclear signatures that may be related to the nuclear activities developed in the inspected facility. This work was used as a case of study a real uranium conversion plant of the nuclear fuel cycle of IPEN. The strategy proposed uses different analytical techniques, such as alpha radiation meter, SEM-EDX and ICP-MS to identify signatures of uranium adhered to the swipe samples. In the swipe samples analysis, it was possible to identify particles of UO{sub 2}F{sub 2} and UF4 through the morphological comparison and semi-quantitative analyses performed by SEM-EDX technique. In this work, methods were used that as a result has the average isotopic composition of the sample, in which the enrichment ranged from 1.453 ± 0.023 to 18.24 % ± 0.15 % in the {sup 235}U isotope. Through these externally collections, a non-intrusive sampling, it was possible to identify enriched material handling activities with enrichment of 1.453 % ± 0.023 % to 6.331 ± 0.055 % in the isotope {sup 235}U, as well as the use of reprocessed material, through the identification of the {sup 236}U isotope. The uncertainties obtained for the n({sup 235}U)/n({sup 238}U) ratio varied from 0.40% to 0.86 % for the internal swipe samples. (author)

  9. Fuel densification study about uranium- 7% nanostructured gadolinium (Gd{sub 2}O{sub 3}); Estudo da densificacao do combustivel uranio - 7% gadolinio (Gd{sub 2}O{sub 3}) nanoestruturado

    Energy Technology Data Exchange (ETDEWEB)

    Serafim, Antonio da Costa

    2016-11-01

    The sintering process of UO{sub 2}-Gd{sub 2}O{sub 3} pellets has been investigated in this work for its importance in the nuclear industry and for its complex behavior during sintering. Sintering blockage occurs from 1300 deg C upwards, when densification is shifted toward higher temperatures and the final density obtained is decreased. This research includes the development of nuclear fuel for power reactors in order to increase its efficiency inside the reactor core by raising the burnup. The use of nanosized Gd{sub 2}O{sub 3} was studied in the range from 10 to 30nm, which was added to UO{sub 2}, trying to verify the occurrence of characteristic sintering blockage due to Kirkendall sintering effect observed in previous research. The samples were produced by dry mechanical mixture of UO{sub 2} powder and 7% Gd{sub 2}O{sub 3} (macro- and nanostructured). The powders were compacted and the pellets were sintered at 1700 deg C under H{sub 2} atmosphere. These results indicate that the characteristic blockage during sintering in macrostructured system UO{sub 2}-Gd{sub 2}O{sub 3} occurred in the temperature range of 1300-1500 deg C, which slows down the densification. It was observed a less intense effect when using the nanostructured Gd{sub 2}O{sub 3}; it took place at the temperature of 900 deg C, then facilitating to get an additional densification. The dilatometric tests indicated shrinkage of 22, 18 and 20% respectively in UO{sub 2} pellets, macrostructured UO{sub 2}-7% Gd{sub 2}O{sub 3} and nanostructured UO{sub 2}-7%Gd{sub 2}O{sub 3}. We detected 2% higher shrinkage, when nanostructured Gd{sub 2}O{sub 3} was used instead of macrostructured Gd{sub 2}O{sub 3}, which is used commercially. Then, the nanostructured results showed more adequate density for nuclear fuel usage. (author)

  10. No fluorinated compounds in the uranium conversion process: risk analysis and proposition of pictograms; Os compostos nao fluorados nos processos da conversao do uranio: analise de riscos e proposicao de pictogramas

    Energy Technology Data Exchange (ETDEWEB)

    Jeronimo, Adroaldo Clovis; Oliveira, Wagner dos Santos, E-mail: acejota18@yahoo.com.br, E-mail: oliveira@feq.unicamp.br [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Fac. de Engenharia Quimica; Aquino, Afonso Rodrigues de, E-mail: araquino@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2012-03-15

    The plants comprising the chemical conversion of uranium, which are part of the nuclear fuel cycle, present some risks, among others, because are associated with the non-fluorinated compounds handled in these processes. This study is the analysis of the risks associated with these compounds, i e, the non-fluorinated reactants and products, handled in different chemical processing plants, which include the production of uranium hexafluoride, while emphasizing the responsibilities and actions that fit to the chemical engineer with regard to minimizing risks during the various stages. The work is based on the experience gained during the development and mastery of the technology of production of uranium hexafluoride, the IPEN/ CNEN-SP, during the '80s, with the support of COPESP -Navy of Brazil. (author)

  11. Validation of the technique of kinetic fosforimetria induced by laser for the determination of the concentration of uranium in urine; Validacion de la tecnica de fosforimetria cinetica inducida por laser para la determinacion de la concentracion de uranio en orina

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, C.; Sierra, I.; Benito, P.; Lopez, C.

    2013-07-01

    This paper describes the methodology used to conduct the validation of the method of determination of uranium using the technique of Kinetic Phosphorescence Analyser (KPA) The technical requirements of the standard 17025 stresses the need for validation samples KPA urine of workers exposed to risk of internal contamination. (Author)

  12. Use of radioanalytical methods for determination of uranium, neptunium, plutonium, americium and curium isotopes in radioactive wastes; Utilizacao de metodos radioanaliticos para a determinacao de isotopos de uranio, plutonio, americio e curio em rejeitos radioativos

    Energy Technology Data Exchange (ETDEWEB)

    Geraldo, Bianca

    2012-07-01

    Activated charcoal is a common type of radioactive waste that contains high concentrations of fission and activation products. The management of this waste includes its characterization aiming the determination and quantification of the specific radionuclides including those known as Difficult-to-Measure Radionuclides (RDM). The analysis of the RDM's generally involves complex radiochemical analysis for purification and separation of the radionuclides, which are expensive and time-consuming. The objective of this work was to define a methodology for sequential analysis of the isotopes of uranium, neptunium, plutonium, americium and curium present in a type of radioactive waste, evaluating chemical yield, analysis of time spent, amount of secondary waste generated and cost. Three methodologies were compared and validated that employ ion exchange (TI + EC), extraction chromatography (EC) and extraction with polymers (ECP). The waste chosen was the activated charcoal from the purification system of primary circuit water cooling the reactor IEA-R1. The charcoal samples were dissolved by acid digestion followed by purification and separation of isotopes with ion exchange resins, extraction and chromatographic extraction polymers. Isotopes were analyzed on an alpha spectrometer, equipped with surface barrier detectors. The chemical yields were satisfactory for the methods TI + EC and EC. ECP method was comparable with those methods only for uranium. Statistical analysis as well the analysis of time spent, amount of secondary waste generated and cost revealed that EC method is the most effective for identifying and quantifying U, Np, Pu, Am and Cm present in charcoal. (author)

  13. Availability of uranium present in the sludge generated at two stations of potable water treatment; Disponibilidad del uranio presente en el fango generado en dos estaciones de tratamiento de agua potable

    Energy Technology Data Exchange (ETDEWEB)

    Munoz-Serrano, A.; Baeza, A.; Salas, A.; Guillen, J.

    2013-07-01

    During the treatment is carried out in a Station Potable Water Treatment Plant sludge enriched are produced in components that have been removed from the water. The concentration and availability of radionuclides accumulated in a sludge during coagulation-flocculation will condition possible later use, so it is essential to carry out the characterization of sludge and its chemical speciation. (Author)

  14. Behavior of uranium isotopes along a tidal cycle in a study affected by acid mine drainage; Comportamiento de los isotopos de uranio a lo largo de un ciclo mareal en un estuario afectado por denaje acido de minas

    Energy Technology Data Exchange (ETDEWEB)

    Hierro, A.; Martin, J. e.; Olias, M.; Garcia, C.; Bolivar, J. P.

    2013-07-01

    The Tinto and Odiel rivers converge in an estuarine system known as the Ria de Huelva, which is an ecosystem of great interest, conditioned by hydrochemical facts. The main objective of this study was to analyze the behavior of uranium isotopes in the waters of the Red River estuary in a tidal cycle under hydrochemical conditions of high gradients of salinity and pH generated by the acidic waters of the Rio Tinto and seawater. (Author)

  15. Determination of uranium and thorium isotopes and polonium in sediment profiles from Baixada Santista, SP; Determinacao de isotopos de uranio e torio e polonio em perfis de sedimento da Baixada Santista, SP

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, Guilherme da Franca

    2010-07-01

    The objective of the present work is to determine the activity concentration of uranium and thorium isotopes and polonium in estuarine sediments from Baixada Santista. The area comprehends nine cities in the Brazilian coast (Bertioga, Guaruja, Santos, Sao Vicente, Cubatao, Praia Grande, Mongagua, Itanhaem and Peruibe). It is one of the most important industrial areas in Brazil due to the large number of industries operating in Cubatao, such as steel, petrochemical and fertilizer industries. That, together with a large population, causes a negative impact on the marine biota. In the present work 10 profiles of sediment cores, with depth varying from 41 to 98 cm, were analyzed. The cores were obtained from Santos, Cubatao, Sao Vicente and Bertioga. The cores were sliced every 2 cm and were treated with both physical and chemical processes, including drying, grinding and sieving. The samples were dissolved by acid digestion, till total dissolution and destruction of organic matter. After the acid digestion, the samples were filtered and evaporated till dryness. The radiochemical techniques used to separate the radionuclides and to prepare the final source for alpha counting were ion exchange chromatography and spontaneous deposition for polonium and electrodeposition for U and Th. The final sources were counted in a surface barrier alpha spectrometer. Values obtained for the radionuclides analyzed were similar to the activity concentrations of sediments in non polluted areas, with the exception of a few samples that showed anthropic influence. (author)

  16. Study of internal exposure to uranium compounds in fuel fabrication plants in Brazil; Estudo da exposicao interna a compostos de uranio na fabricacao do elemento combustivel nuclear no Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Maristela Souza

    2006-07-01

    The International Commission on Radiological Protection (ICRP) Publication 66 and Supporting Guidance 3) strongly recommends that specific information on lung retention parameters should be used in preference to default values wherever appropriate, for the derivation of effective doses and for bioassay interpretation of monitoring data. A group of 81 workers exposed to UO{sub 2} at the fuel fabrication facility in Brazil was selected to evaluate the committed effective dose. The workers were monitored for determination of uranium content in the urinary and faecal excretion. The contribution of intakes by ingestion and inhalation were assessed on the basis of the ratios of urinary to fecal excretion. For the selected workers it was concluded that inhalation dominated intake. According to ICRP 66, uranium oxide is classified as insoluble Type S compound. The ICRP Supporting Guidance 3 and some recent studies have recommended specific lung retention parameters to UO{sub 2}. The solubility parameters of the uranium oxide compound handled by the workers at the fuel fabrication facility in Brazil was evaluated on the basis of the ratios of urinary to fecal excretion. Excretion data were corrected for dietary intakes. This paper will discuss the application of lung retention parameters recommended by the ICRP models to these data and also the dependence of the effective committed dose on the lung retention parameters. It will also discuss the problems in the interpretation of monitoring results, when the worker is exposed to several uranium compounds of different solubilities. (author)

  17. The fluorimetry for control of internal contamination of exposed workers to natural and enriched uranium; A fluorimetria para o controle da contaminacao interna dos trabalhadores expostos a uranio natural e enriquecido

    Energy Technology Data Exchange (ETDEWEB)

    Gaburo, J.C.; Todo, A.S.; Sordi, G.M.A.A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)]. E-mail: janetegc@net.ipen.br

    2000-07-01

    This study is a part of bioassay program revision applied to the uranium processing plants at IPEN-CNEN/SP. The workers of these facilities handle both natural uranium and uranium compounds with different isotopic composition which could reach up to 20% in 235 U. The most commonly employed techniques for the determination of uranium in urine at IPEN are fluorimetry and alpha spectrometry with detection limit of 1.0 mgL-1. and 1,0 mBqL-1 , respectively. Based in advantages and disadvantages of each technique it is very important to identify the workers groups that should be submitted for these analysis. In this report a limiting value of uranium concentration in urine, mgL-1, obtained by fluorimetry is proposed. All the results greater than these limiting value indicate the necessity to carry out a additional measurement by alpha spectroscopy. The uranium mass that result in a pre-determined limit committed effective dose is function of isotopic composition. Consequently, the predicted value of the measured of urinary excretion is function of isotopic composition also and depends of absorption characteristics when inhaled and of the monitoring interval considered. In this report the uranium concentration values for reference levels and limits doses are determined. Based on these results the procedures to use the fluorimetry or both fluorimetry and alpha-spectrometry were adopted. (author)

  18. Solvent-extraction methods applied to the chemical analysis of uranium. III. Study of the extraction with inert solvents; Metodos de extraccion con disolventes aplicados al analisis quimico del uranio. III. Estudio de la extraccion con disolvente inertes

    Energy Technology Data Exchange (ETDEWEB)

    Vera Palomino, J; Palomares Delgado, F; Petrement Eguiluz, J C

    1964-07-01

    The extraction of uranium on the trace level is studied by using tributylphosphate as active agent under conditions aiming the attainment of quantitative extraction by means of a single step process using a number of salting-out agents and keeping inside the general lines as reported in two precedent papers. Two inert solvents were investigated, benzene and cyclohexane, which allowed to derive the corresponding empirical equations describing the extraction process and the results obtained were compared with those previously reported for solvents which, like ethyl acetate and methylisobuthylketone, favour to a more or less extend the extraction of uranium. (Author) 4 refs.

  19. Determination of the ratio between phosphorus and uranium in surface waters selected in the State of Mexico; Determinacion de la relacion entre fosforo y uranio en cuerpos de agua seleccionados en el Estado de Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Ordonez R, E

    2001-07-01

    The agricultural regions lately, they have suffered a severe contamination for the big ones quantities of chemical fertilizers and of pesticides applied to improve their production and quality, increasing these in areas with temperatures but you lower that the average. For the importance of the physicochemical processes that they are made in the waters to settle down surface near to agricultural fields, the physicochemical characteristics were analysed of these waters to determine the contributions that they carry out the phosphate fertilizers that are carried by the escorrentia toward the borders and to make a pursuit of their variability during an agricultural cycle, in times of the summertime and of rains, as well as to observe the effect of the depth in these physicochemical properties. Its were sampling three borders and a spring that it served of white, all them located in the suburbs of the Xinantecatl (Nevado de Toluca), municipality of Zinacantepec, State of Mexico, area with the temperatures but drops registered in the region. They were carried out samplings in the first days of the months of April, July and November. The points of those sampled borders were the influent, the effluent and 3 different depths (lm, 3m and 5m). where was not possible sampling all the points, its were sampling only the one influent and the effluent. The selected physicochemical parameters were the temperature, the pH, the conductivity electric and the one oxygenates dissolved This determination in situ you carries out with a team portable of type Check-Mate, of interchangeable electrodes. The certain anions they were phosphates, nitrates, sulfates and bicarbonates; the measurement of the concentration of anions, one carries out for ultraviolet-visible light spectroscopy and titration. The cations analysed they were sodium, potassium, iron, calcium and magnesium. The cations concentration was determined by atomic absorption spectroscopy. The determination of the uranium concentration it was made by means of neutron activation analysis. The physicochemical parameters diminished of value in the temporary analysis, as long as those anions and the cations didn't show a behavior defined in this same analysis, while in the analysis in depth these parameters presented minimum changes. In the modelling one for computer packages, the results of the speciation analysis chemistry, by means of the Medusa program, they revealed that the species of uranium in solution but abundant they were phosphate uranyl monoacid, tris uranyl carbonate and bis uranyl carbonate and, in smaller proportion, the species of aqueous uranyl hydroxide. The characterization of waters for the program GWW gave as a result that the facies but representative it was the bicarbonate magnesia. In the study of the quality of the one it dilutes with ends of agricultural watering, they were classified as capable for this purpose. The analysis statistical one carries out with base in the correlation coefficient whose value among the uranium and the match is moderated in three sampling points. (Author)

  20. Concentration of uranium in the urine of the staff of a nuclear power plant. [Personnel engaged in chemistry and metallurgy of uranium]. Concentrazione d'uranio nelle urine del personale di un centro nucleare

    Energy Technology Data Exchange (ETDEWEB)

    Camera, V.; Giubileo, M.

    1962-07-01

    The concentration of natural uranium in the urine of 78 workers from the groups of industrial chemistry and metallurgy of uranium, was followed for 3 years. A total of 1471 analyses were done with the fluorometric method. The urine checks were done every week, or every 15 days or more according to the amount of exposure, which was evaluated by investigations done at the place of work and on the basis of information collected from the workers during the periodical medical examinations. The validity of this criterion was proved by the data obtained: the majority (74%) of the analyses of personnel least exposed revealed levels equal to or inferior to 1 gamma/liter, whereas (66%) the group with an intermediate risk showed 1 to 5 gamma/liter, and in the group most exposed levels of 5-10 gamma/liter were found in 37% of the cases; from 10-20 gamma/liter in 19%; and from 20-50 gamma/liter in 7% of the cases. Only 1% of the samples had a level superior to 50 gamma/liter. The attempt to establish a correlation between the level of uranium found in the air and in the urine gave no tenable indication concerning the real work risk, due to the variability of atmospheric contamination with time and the incessant movement of almost all the workers from one laboratory to another during the day.

  1. An outline of the application of an environmental management system to the PRAMU (Uranium Mining Environmental Restitution Project); Ejemplo de aplicacion de un sistema de gestion ambiental en el PRAMU: Proyecto de Restitucion Ambiental de la Mineria del Uranio

    Energy Technology Data Exchange (ETDEWEB)

    Smetniansky de De Grande, Nelida; Avila Cadena, Guadalberto; Cardozo, Damian [Comision Nacional de Energia Atomica, Buenos Aires (Argentina). Unidad Ejecutora del Proyecto PRAMU

    2000-07-01

    In Argentina the National Atomic Energy Commission (CNEA) has the responsibility to restore uranium mining facilities, when milling operations have been shut down. To carry out this clean up actions CNEA created the Project for Uranium Mining Environmental Restoration (PRAMU in Spanish). To take into account the environmental aspects of the restoration activities, the PRAMU includes in its management an Environmental Management System (SGA in Spanish), which is of central importance in determining the environmental policy, objectives and targets. In this work a general view of the Environmental Management System is presented and an example of one of the environmental programs to be implemented is detailed. (author)

  2. The uranium works prospection developed since 1976 in the Republica Oriental del Uruguay[Geochemical prospection of Uranium in Uruguay]; Los trabajos de prospeccion de uranio desarrollados a partir de 1976 en la Republica Oriental del Uruguay

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1979-07-01

    In this report there are described the works of exploration of uranium developed in the Oriental Republic of the Uruguay from 1976.Then do the precedents and of an analysis of the big zones. Dates structural that compose the geology of the Uruguay, describe the works carried out in general exploration, towards the North-East of the country and of detail in the same zone: Districts Long Hill South and The Canes. Finally, a series of considerations are carried out on the perspectives of uranium in the Uruguay, in relation by the sedimentary areas: Devonian (formation Cerrezuelo) and Gondwana (formation San Gregorio and Three Islands) and, on the crystalline areas, of the center, southwest and this one.

  3. Method of semi-automatic high precision potentiometric titration for characterization of uranium compounds; Metodo de titulacao potenciometrica de alta precisao semi-automatizado para a caracterizacao de compostos de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Cristiano, Barbara Fernandes G.; Dias, Fabio C.; Barros, Pedro D. de; Araujo, Radier Mario S. de; Delgado, Jose Ubiratan; Silva, Jose Wanderley S. da, E-mail: barbara@ird.gov.b, E-mail: fabio@ird.gov.b, E-mail: pedrodio@ird.gov.b, E-mail: radier@ird.gov.b, E-mail: delgado@ird.gov.b, E-mail: wanderley@ird.gov.b [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Lopes, Ricardo T., E-mail: ricardo@lin.ufrj.b [Universidade Federal do Rio de Janeiro (LIN/COPPE/UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-Graduacao de Engenharia. Lab. de Instrumentacao Nuclear

    2011-10-26

    The method of high precision potentiometric titration is widely used in the certification and characterization of uranium compounds. In order to reduce the analysis and diminish the influence if the annalist, a semi-automatic version of the method was developed at the safeguards laboratory of the CNEN-RJ, Brazil. The method was applied with traceability guaranteed by use of primary standard of potassium dichromate. The standard uncertainty combined in the determination of concentration of total uranium was of the order of 0.01%, which is better related to traditionally methods used by the nuclear installations which is of the order of 0.1%

  4. Detection of outliers by neural network on the gas centrifuge experimental data of isotopic separation process; Aplicacao de redes neurais para deteccao de erros grosseiros em dados de processo de separacao de isotopos de uranio por ultracentrifugacao

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Monica de Carvalho Vasconcelos

    2004-07-01

    This work presents and discusses the neural network technique aiming at the detection of outliers on a set of gas centrifuge isotope separation experimental data. In order to evaluate the application of this new technique, the result obtained of the detection is compared to the result of the statistical analysis combined with the cluster analysis. This method for the detection of outliers presents a considerable potential in the field of data analysis and it is at the same time easier and faster to use and requests very less knowledge of the physics involved in the process. This work established a procedure for detecting experiments which are suspect to contain gross errors inside a data set where the usual techniques for identification of these errors cannot be applied or its use/demands an excessively long work. (author)

  5. Contribution to the spectrographic determination of impurities in uranium by the carrier distillation method; Nuevas aportaciones a la determinacion espectrografica de impurezas en materiales de uranio por el metodo de distilacion fraccionada con portador

    Energy Technology Data Exchange (ETDEWEB)

    Capdevila, C

    1967-07-01

    The carrier distillation method for the determination of impurities in uranium has been modified in order to get a greater sensitivity. Electrodes 9.5 mm. diam. with a crater 7 mm. diam. and 10 mm. deep have been used, being the weigh of charge 300 mg.. The elements considered were: Al, As, B, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, P, Pb, Si, Sn, Ti and V, over the range 0.01 to 30 ppm. (Author) 13 refs.

  6. Bomb reduction of uranium tetrafluoride. Part II: Influence of the addition elements in the reduction process; Reduccion del tetrafluoruro de uranio en bomba cerrada. Parte II: Influencia de elementos de adicion en la reducion

    Energy Technology Data Exchange (ETDEWEB)

    Anca Abati, R; Lopez Rodriguez, M

    1962-07-01

    This work shows the influence of uranium oxide and uranyl fluoride in the reduction of uranium with Ca and Mg. These additions are more harmful when using smaller bombs. The uranyl fluoride has influence in the reduction process; the curves yield-concentration shows two regions depending upon the salt concentration. The behaviour of this addition in these regions can be explained following the different decompositions that can take place during the reduction process. (Author) 9 refs.

  7. Projects development for mining-metallurgical units for production of uranium concentrates. An analysis an a methodology; Desarrollo de proyectos para unidades minero-metalurgicas para produccion de concentrados de uranio. Un analisis y una metodologia

    Energy Technology Data Exchange (ETDEWEB)

    Ajuria G, S; Blanco P, B; Manzanera Q, C; Pena A, J [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    1978-07-15

    An analysis and a methodology for the complete development of a mining- metallurgist project is presented, from the sampling and the evaluation of a deposit until the outburst of a metallurgical plant. The main objectives of this work are three: On one hand it is to establish a methodology for standardize the internal activities of the Sub management of Benefits. It is convenient standardize the experimental procedures, the evaluation approaches and the form of presentation of results so that they are directly comparable and that it is easy their interpretation and use. Given the nature so variable of the minerals this document cannot be but that a guide and it is indispensable that in all moment the personnel that develops these activities uses his knowledge, experience and professional approach to obtain the best results. On the other hand it is to establish a base to facilitate the coordination of the activities of the Sub management of Benefit with other work groups, inside of and outside of the INEN that should collaborate in the projects. Finally it is to present a vision of group of the whole project like reference base for the participant personnel. Many of the specialists that contribute to the project would not be metallurgists, but rather they practice other disciplines. It is therefore convenient to facilitate the one that are formed an image of the complete project. (Author)

  8. Attachment GEO 1 Permic basin geology in northeast of Uruguay: deposit exam about Uranium traces; Anexo GEO 1 Geologia de la Cuenca Permica del nordeste del Uruguay: examen sedimentologico sobre los indicios de Uranio

    Energy Technology Data Exchange (ETDEWEB)

    L' Homer, A; Manigault, B; Doyhenart, A; Rossi, P

    1983-07-01

    The article is about different deposit of Uranium traces and their Sedimentology analysis. A revision of main works have been given and Durazno and Gondwana groups, Cerrezuelo, Cordobes, La Paloma, San Gregorio, Tres Islas formations.

  9. Geology of permian basin in the northeast of Uruguay: Sedimentology exam about uranium trace[Study of Uranium geochemical prospection in Uruguay]; Geologia de la cuenca permica del nordeste del Uruguay: examen sedimentologico sobre los indicios de uranio

    Energy Technology Data Exchange (ETDEWEB)

    L' Homer, A; Manigault, B; Doyhernart, A; Rossi, P; Spoturno, J; De Santana, H; Vaz Chaves, N

    1982-07-01

    The Uranium project was prepared from BRGM to DINAMIGE. Its has got three zones of investigation: zone 1 composed by precambrian basin in the N W; zone 2 the precambrian insular shelf and rocks belts; zone 3 wich include parts of the basin Cretaceous in Salto and Santa Lucia.

  10. Qualitative evaluation of environmental radiological impact in a phosphate associated uranium conventional mine: Santa Quiteria Project, CE, Brazil; Avaliacao qualitativa do impacto radiologico ambiental em uma mineracao convencional de fosfato com uranio associado: o Projeto Santa Quiteria

    Energy Technology Data Exchange (ETDEWEB)

    Reis, Rocio G. dos; Santo, Aline Sa E., E-mail: rocio@ird.gov.br, E-mail: alinesah@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    The aim of this study is to identify and evaluate qualitatively the main potential sources of mineral and installation terms of Santa Quiteria, CE, Brazil, evaluating their possible impacts on the environment. The key terms sources in the production of phosphoric acid are usually: the dig of the mines, tailings dams and phospho plaster stack. Thus, this work intends to inform the academic community about this issue, as well as the population in general and also, acting proactively in order to warn about the possible environmental impacts, so that actions to compensate, minimize or avoid these radiological impacts on the environment, can be included in the planning of the industrial mineral project of Santa Quiteria (author)

  11. Uranium, radon-222 and polonium-210 in drinking waters from metropolitan area of Recife, PE, Brazil; Uranio, radonio-222 e polonio-210 em aguas de abastecimento publico da regiao metropolitana do Recife

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Cleomacio Miguel da

    2000-04-01

    There is only scarce information on the presence of radionuclides in water for public consumption in Brazil. A recently issued federal regulation requires that waters from public supplies be screened to determine their content of alpha and beta emitters. In order to comply with this requirement the present work was carried out with the purpose of determining the concentration of natural uranium, {sup 222} Rn and {sup 210} Po in water supplies in the metropolitan region of Recife, Brazil. The analyses were performed in 17 points of supply of superficial water and 94 points of groundwater supply. The concentrations of uranium were determined by the fluorimetric method, whereas the liquid scintillation method was used to determine the concentration of {sup 222} Rn. Polonium-210, on the other hand, was determined by alpha spectrometry, following its spontaneous deposition on copper disks. The water analyzer presented uranium concentrations varying from 35.3 to 1146.5 mBq/L for superficial resources and from 20.2 to 919.15 mBq/L for underground sources. The concentration of uranium in superficial water showed significant correlation with some parameters such as conductivity, alkalinity and total hardness, as well as, with the concentrations of Ca, Mg, Cl, K, SO{sub 4} and Mn. No correlation, however, was shown with the concentrations of Fe, NO{sub 2} and NO{sub 3}. The concentrations of {sup 222} Rn varied from 5.3 to 83.7 Bq/L in the groundwater analyzer. Radon concentration was not measured in superficial water due to the high emanation rate of radon in open air conditions. As far as {sup 210} Po is concerned, the analyses showed concentrations ranging from <22 mBq/L (the lowest limit of detection) to 57.4 mBq/L for superficial water and from <22 to 813 mBq/L for ground water samples. The concentrations of {sup 210} Po did not show and correlation with physico-chemical parameters. The average concentrations of uranium and {sup 210} Po in superficial water were of 44.7 mBq/L, respectively. These values correspond to effective doses of 5.8 x 10{sup -4} mSv/yr and 4.5 x 10{sup -2} mSv/yr, for uranium and {sup 210} Po, respectively. The average values for the concentrations of uranium, {sup 222} Rn and {sup 210} Po in ground samples, on the other hand, were 106.6 mBq/L, 24,3 Bq/L and 30 mBq/L, respectively, corresponding to effective doses of 8.0 x 10{sup -4} mSv/yr, 1.3 mSv/yr and 0.47 mSv/yr, respectively. (author)

  12. Validation of methods to measure uranium isotopes using magnetic sector mass spectrometry with inductively coupled plasma source; Validacion de metodos para medir isotopos de uranio usando espectrometria de masas de sector magnetico con fuente de plasma acoplado inductivamente

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez M, H. [Universidad del Centro de Mexico, Capitan Caldera 75, Col. Tequixquiapan, 78250 San Luis Potosi, SLP (Mexico); Rios L, M. J. [Universidad Autonoma de San Luis Potosi, Facultad de Enfermeria y Nutricion, Unidad de Posgrado, Av. Nino Artillero 130, 78210 San Luis Potosi, SLP (Mexico); Romero G, E. T., E-mail: hector.hernandez520@gmail.com [ININ, Departamento de Quimica, Laboratorio Forense Nuclear, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2017-10-15

    The mass spectrometry technique with inductively coupled plasma source (Icp-Ms) has been widely used to measure isotopic ratios of elements toxic to human health. Reason for which, in this work several measurement methods for the analysis of uranium isotopes in different matrices were implemented using magnetic sector mass spectrometry with inductively coupled plasma source (Icp-SFMS). Groundwater, sediment, soil and urine were the matrices analyzed, which were supplied by intercomparison tests conducted by the IAEA and Association for the Promotion of Quality Control of Medical Biology Analysis in Radio-toxicology. The procedures used in the treatment of soil, sediment and water samples were based on US EPA methods. In the case of the urine sample, the preparation was rapid (1:20 dilution). The average of the results obtained in yield of each matrix was 94, 71, 72 and 78% for water, urine, soil and sediment respectively. In addition, the precision in terms of standard relative deviation was less than 5% and the accuracy was less than 4%. In conclusion, the Icp-SFMS is a very sensitive technique for measuring isotopes of U in different matrices. However, careful tuning is necessary, especially in the mass regions of interest 234, 235 and 238 if an external quantification is considered using natural U solutions. (Author)

  13. Quantification of uranium levels in groundwater in the municipality of San Diego de la Union Mexico; Cuantificacion de los niveles de uranio en agua subterranea en el municipio de San Diego de la Union Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez M, H. [Universidad del Centro de Mexico, Capitan Caldera 75, Col. Tequixquiapan, 78250 San Luis Potosi, SLP (Mexico); Rios L, M. J.; Gaytan H, D. [Universidad Autonoma de San Luis Potosi, Facultad de Enfermeria y Nutricion, Unidad de Posgrado, Av. Nino Artillero 130, 78210 San Luis Potosi, SLP (Mexico); Romero G, E. T., E-mail: hector.hernandez520@gmail.com [ININ, Departamento de Quimica, Laboratorio Forense Nuclear, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2017-10-15

    The objective of this work was to quantify the levels of uranium (U) in groundwater from 22 wells in the municipality of San Diego de la Union Mexico. The sampled wells were classified as not regularized and regularized according to records of the National Water Commission and classified by zones A, B, C, D and E. Samples were collected in triplicate in 1 L bottles, then acidified with ultra pure HNO{sub 3} at 2% v/v and conserved at 4 degrees Celsius until analysis by mass spectrometry with magnetic sector with inductively coupled plasma source (Icp-SFMS). The preparation method was the acid digestion in the open system and re-concentration of the sample. In addition, 1 μg L{sup -1} of indium (In) was used as a tracer to know the performance of the method. Finally, the samples were diluted in 10 ml and introduced to the Icp-SFMS to measure in low resolution the U isotopes (U-234, U-235 and U-238). The average results obtained from total U were: A= 3.65 ± 1.89 μg L{sup -1}, B= 6.37 ± 1.46 μg L{sup -1}, C= 3.20 ± 2.27 μg L{sup -1}, D= 3.87 ± 1.31 μg L{sup -1} and E= 4.44 ± 1.17 μg L{sup -1}. According to the official Mexican standard NOM-014-CONAGUA-2003, the U levels found in the groundwater of San Diego de la Union Mexico do not exceed the permissible limits of 30 μg/L. (Author)

  14. Evaluation exposure to the ionizing radiation of workers during the operation of first Brazilian uranium mine; Avaliacao da exposicao de trabalhadores a radiacao ionizante durante a operacao da primeira mina de uranio do Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Wagner de S.; Oliveira, Sergio Q. de; Py Junior, Delcy de A.; Dantas, Marcelino V.A.; Silva, Ana Claudia A.; Garcia Filho, Oswaldo, E-mail: wspereira@inb.gov.b, E-mail: sergioquinet@inb.gov.b, E-mail: delcy@inb.gov.b, E-mail: marcelino@inb.gov.b, E-mail: anasilva@inb.gov.b, E-mail: ogarcia@inb.gov.b [Industrias Nucleares do Brasil (UTM/INB), Pocos de Caldas, MG (Brazil). Unidade de Tratamento de Minerios. Servico de Radioprotecao

    2011-10-26

    The production of uranium in Brazil initiated, in industrial scale, in the year of 1982, in the Miner-Industrial Complex at Pocos de Caldas, Minas Gerais, Brazil. This paper analysed the data of 13410 individual historic of dose, registered along the years of work, bay the radioprotection service of installation. Descriptive statistics and frequency histograms based on dose historic, and the annual distribution doses and the accumulated doses were evaluated during the functioning period of the CIPC, and his adequacy to the in force legislation at the time of it operation

  15. Development of a high density fuel based on uranium-molybdenum alloys with high compatibility in high temperatures; Desenvolvimento de um combustivel de alta densidade a base das ligas uranio-molibdenio com alta compatibilidade em altas temperaturas

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Fabio Branco Vaz de

    2008-07-01

    This work has as its objective the development of a high density and low enriched nuclear fuel based on the gamma-UMo alloys, for utilization where it is necessary satisfactory behavior in high temperatures, considering its utilization as dispersion. For its accomplishment, it was started from the analysis of the RERTR ('Reduced Enrichment for Research and Test Reactors') results and some theoretical works involving the fabrication of gamma-uranium metastable alloys. A ternary addition is proposed, supported by the properties of binary and ternary uranium alloys studied, having the objectives of the gamma stability enhancement and an ease to its powder fabrication. Alloys of uranium-molybdenum were prepared with 5 to 10% Mo addition, and 1 and 3% of ternary, over a gamma U7Mo binary base alloy. In all the steps of its preparation, the alloys were characterized with the traditional techniques, to the determination of its mechanical and structural properties. To provide a process for the alloys powder obtention, its behavior under hydrogen atmosphere were studied, in thermo analyser-thermo gravimeter equipment. Temperatures varied from the ambient up to 1000 deg C, and times from 15 minutes to 16 hours. The results validation were made in a semi-pilot scale, where 10 to 50 g of powders of some of the alloys studied were prepared, under static hydrogen atmosphere. Compatibility studies were conducted by the exposure of the alloys under oxygen and aluminum, to the verification of possible reactions by means of differential thermal analysis. The alloys were exposed to a constant heat up to 1000 deg C, and their performances were evaluated in terms of their reaction resistance. On the basis of the results, it was observed that ternary additions increases the temperatures of the reaction with aluminum and oxidation, in comparison with the gamma UMo binaries. A set of conditions to the hydration of the alloys were defined, more restrictive in terms of temperature, time and pre-treatment to stabilize the gamma structure. The addition of a bit low ternary excess and formation of an intergranular phase, the increase in stability, it was demonstrated that there is not a damage in the formation of their powders.(author)

  16. Training of secondary phases on UO{sub 2}. Uranyl phosphates and uranium peroxide; Formacion de fases secundarias sobre UO{sub 2}. Fosfatos de uranilo y peroxido de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Gimenez, J.; Rey, A.; Pablo, J. de; Casas, I.

    2008-07-01

    One of the main processes that can control radionuclides migration is mineral phase precipitation, known as secondary phases. The formation of one of these phases more stable than UO{sub 2} at repository conditions, could act as a barrier between nuclear waste and groundwater. This modifies the radiation that arrives to the dissolution, blocking dissolution of UO{sub 2} matrix and affecting to radionuclide release. So, is important to know the possible secondary phases to precipitate during SNF (spent nuclear fuel) alteration and its stability at repository conditions. Several experiments of SNF dissolution in groundwater have observed the formation of uranium secondary phases. Nevertheless, these experiments have been developed in specific conditions and they haven't arrived to study the effect of several parameters, such as complexions as phosphate. The rol of phosphate on to dissolution of UO{sub 2} and uranium-phosphate phase formation is necessary to know repository assessment. Uranyl peroxides have been found also in several studies about lixiviation in presence of hydrogen peroxide, which is the expected oxidant for med from the water radiolysis. In this work we performed a study about the stability of these phases. The phases obtained have been characterized with X ray diffraction (XRD). The particle size, shape and chemical composition have been studied by scanning electron microscopy (SEM). A topographic analysis of UO{sub 2} surface in contact with ground water and phosphate media have been performed by means of atomic force microscopy (AFM). The uranium concentration evolution in solution have been followed with ICP-MS. Stability in relation to radiation of uranyl peroxide have been developed with electron transmission microscopy (TEM), and thermal stability with a thermo gravimetry device (TG) and Differential scanning calorimetry (DSC). (Author)

  17. Modification of zirconium diphosphate with salicylic acid and its effect on the uranium (Vi) sorption; Modificacion del difosfato de circonio con acido salicilico y su efecto sobre la sorcion de uranio (VI)

    Energy Technology Data Exchange (ETDEWEB)

    Almazan T, M. G.; Garcia G, N. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Simoni, E., E-mail: guadalupe.almazan@inin.gob.mx [Universidad Paris Sud, Instituto de Fisica Nuclear, Georges Clemenceau No. 15, Orsay (France)

    2014-10-15

    The surface of zirconium diphosphate (ZrP{sub 2}O{sub 7}) was modified with salicylic acid and its effect was evaluated on the uranium (Vi) sorption. The modified surface of the material was analyzed with different analytical techniques among which are included the atomic force microscopy, scanning electron microscopy and X-ray photoelectron spectroscopy. This analysis allowed showing that the salicylic acid is being held on the surface of the zirconium diphosphate. The reactivity of modified zirconium diphosphate compared with uranium (Vi) was investigated using the classical method of batch sorption. The analysis of sorption isotherms shows that the salicylic acid has an important effect in the uranium (Vi) sorption. According to the study conducted, the interaction among the uranium (Vi) and the surface of zirconium diphosphate modified with the salicylic acid most likely leads to the complexes formation of binary (U(Vi)/ZrP{sub 2}O{sub 7}) and ternary (U(Vi)/salicylate/ZrP{sub 2}O{sub 7}) surface. (Author)

  18. Removing and recovering of uranium from the acid mine waters by using ion exchange resin; Remocao e recuperacao de uranio de aguas acidas de mina por resina de troca ionica

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, Marcos Roberto Lopes do

    1998-07-01

    Ion exchange using resins is one of the few processes capable of reducing ionic contaminants in effluents to very low levels. In this study the process was used to remove and recovery uranium from acid mine waters at Pocos de Caldas-MG Uranium Mining and Milling Plant. The local mineralogical features, allied to the biogeochemical phenomena, owing to presence of pyrite in the rock piles, moreover another factors, resulting acid drainage with several pollutants, including uranium ranging from 6 to 14 mg/l, as sulfate complex, that can be removed by anionic exchanger. The iron interference is eliminated by lime pretreatment of water, increasing pH from 2.6 to 3.3-3.8 to precipitate this cation, without changing the uranium amount. Eight anionic resins were tested, based on the uranium loading, in sorption studies. Retention time, and pH influence was verified for the exchanger chose. With breakthrough of 1 mg U/L and 10 mg U/l in the feed solution, the uranium decontamination level was 94%. Typical values of loading resin were 20-30 g U/l and 70-90 g SO{sub 4}/l. Uranium elution was done with Na Cl solution. Retention time, saline, and acid concentration were the parameters studied. The concentrate, obtained from the eluate by ammonia precipitation, presented uranium (86,8% as U{sub 3} O{sub 8}) and impurities within commercial specifications. (author)

  19. Concentration of uranium in the urine of the staff of a nuclear power plant. [Personnel engaged in chemistry and metallurgy of uranium]. Concentrazione d'uranio nelle urine del personale di un centro nucleare

    Energy Technology Data Exchange (ETDEWEB)

    Camera, V.; Giubileo, M.

    1962-07-01

    The concentration of natural uranium in the urine of 78 workers from the groups of industrial chemistry and metallurgy of uranium, was followed for 3 years. A total of 1471 analyses were done with the fluorometric method. The urine checks were done every week, or every 15 days or more according to the amount of exposure, which was evaluated by investigations done at the place of work and on the basis of information collected from the workers during the periodical medical examinations. The validity of this criterion was proved by the data obtained: the majority (74%) of the analyses of personnel least exposed revealed levels equal to or inferior to 1 gamma/liter, whereas (66%) the group with an intermediate risk showed 1 to 5 gamma/liter, and in the group most exposed levels of 5-10 gamma/liter were found in 37% of the cases; from 10-20 gamma/liter in 19%; and from 20-50 gamma/liter in 7% of the cases. Only 1% of the samples had a level superior to 50 gamma/liter. The attempt to establish a correlation between the level of uranium found in the air and in the urine gave no tenable indication concerning the real work risk, due to the variability of atmospheric contamination with time and the incessant movement of almost all the workers from one laboratory to another during the day.

  20. Uranium tetrafluoride reduction closed bomb. Part I: Reduction process general conditions; Reduccion del tetrafluoruro de uranio en bomba cerrada. Part I. estudio de las variables generales del proceso de reduccion

    Energy Technology Data Exchange (ETDEWEB)

    Anca Abati, R; Lopez Rodriguez, M

    1961-07-01

    General conditions about the metallo thermic reduction in small bombs (250 and 800 gr. of uranium) has been investigated. Factors such as kind and granulometry of the magnesium used, magnesium excess and preheating temperature, which affect yields and metal quality have been considered. magnesium excess increased yields in a 15% in the small bomb, about the preheating temperature, there is a range between which yields and metal quality does not change. All tests have been made with graphite linings. (Author) 18 refs.

  1. Study of new complexes of uranium and comba radical. I.- Complexes defective in sodium carbonate; Estudio de nuevos complejos entre el uranio y el radical CDMBA. I. Complejos con defectos de carbonato sodico

    Energy Technology Data Exchange (ETDEWEB)

    Vera Palomino, J; Galiano Sedano, J A; Parellada Bellod, R; Bellido Gonzalez, A

    1975-07-01

    Some complexes formed in presence of defect of sodium carbonate with respect to the stoichiometric ratio (U): (C0{sub 3}) = 1:3 are studied. This ratio corresponds to the main complex which is responsible for the uranium extraction with CDMBAC organic solutions and from U(VI) aqueous solutions with an excess of sodium carbonate. (Author) 10 refs.

  2. A study of the efficiency of different spectrochemical buffers applied to the uranium ore analysis; Estudio de la eficiencia de diversos reguladores espectroqimicos aplicados al analisis de minerales de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Roca, M; Diaz Guerra, J P

    1981-07-01

    A direct-reading emission spectroscopy method allowing the determination of Al, Ca, Fe, Mg, Mn, Na, P, Si and Ti in geological materials, that are of interest for the prospecting and recovery of uranium, is proposed. Direct-current are between graphite electrodes Is used as the excitation source. Efficiency of Ag{sub 2}O, BaCO{sub 3}, Bi{sub 2}O{sub 3}, CuF{sub 2}, CuO, Ga{sub 2}0{sub 3}, Ge0{sub 2}, graphite, K{sub 2}CO{sub 3}, H{sub 2}B{sub 4}O{sub 7}, Li{sub 2}CO{sub 3}, Ni, PbS, Sb{sub 2}o{sub 4} , SrC0{sub 3}, Ti{sub 2}O{sub 3} and ZnO as spectrochemical buffers has been studied. It has been inferred that through a sample dilution with Li{sub 2}CO{sub 3}, SrC0{sub 3} and graphite powder in the rations 1:10:10:20, respectively, the highest reduction of the matrix effects is achieved. Phosphorus determination Is better performed with PbS as spectrochemical buffer Instead of the indicated above. The action of the selected compounds Is completed by using Co, In, Li and Sr as internal standards, and, as a whole, satisfactory accuracy and reproducibility are attained. (Author) 7 refs.

  3. Program VODAM for treatment of mineral physico-chemical data, with a special application to the uranium case; Programa VODAM para tratamiento de datos de fisico-quimica mineral. Ejemplo de aplicacion al caso del uranio

    Energy Technology Data Exchange (ETDEWEB)

    Santoma Juncadella, L

    1972-07-01

    The VODAM program is written in FORTRAN IV language and makes a physico-chemical analysis of waters, for an element or a number of them, under investigation. A thermodynamical data files is incorporated, and is useful for a low temperature range. It is the basic nucleus for a series of programs of physico-chemical interpretation of hydrogeochemical data and automatic construction of equilibrium diagrams. (Author) 13 refs.

  4. Experimental study of the uranium mobility due to the weathering action at the uraniferous district of Caetite/Lagoa Real, Bahia, Brazil; Estudo experimental da mobilidade do uranio por acao intemperica, distrito uranifero de Caetite/Lagoa Real, Bahia, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Scislewski, Alexandro Rocha

    2004-01-15

    In the present research, the proposal was to develop a preliminary study about the geochemical behavior of determined chemical elements, mainly the uranium, during the action of weathering processes in the rocks that bear the uranium mineralizations of the Caetite-Lagoa Real region, State of Bahia, more specifically of the Jazida Cachoeira uranium mine. To reach this purpose were used samples that represent several stages of the milling process of the uranium ore, so selecting representatives of the host rock, the ore and the treated ore (waste from the milling plant) to be used in the laboratory-controlled experiments. The samples were dried, sieved and finally introduced in the reactors, these adapted from the Flow-Through Reactor of Brantley and Chen. In the geochemical point of view, the results of the experiments showed a distinct behavior between the samples. It was observed that the treated ore, in relation to the host rocks of the ore and the own ore, shown a faster and homogeneous interaction with the leaching solution; it was also noted that in the output solution of the treated ore samples existed a significant complexation of the uranium by the sulfate (S0{sub 4}{sup -2}), ), instead of the non treated samples (host rock and ore) that were complexed mainly by the carbonate (C0{sub 3}{sup -2}). These different results are attributed to the alterations imposed to the rock during the milling process, and occur mainly, during the acid attack in the leaching process of the milling plant. The results and conclusions of this research, in spite of been preliminary, are essential to understand the behavior of the geochemical speciation of the effluent solutions; to understand the alterations of a rock matrix, and finally, to understand the migration chemical behavior of the related chemical elements. It is expected that these results contribute, in the future, to a deeper knowledge of the processes that control the chemical composition of the natural waters from this region in the southwest of Bahia, sites of important and strategic mineral exploitation activities. (author)

  5. Uranium Determination in Samples from Decommissioning of Nuclear facilities Related to the First Stage of Nuclear Fuel Cycle; Determinacion de Uranio en Muestras Procedentes del Desmantelamiento de Instalaciones de la Primera Parte del Cielo del Combustible Nuclear

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, A; Correa, E; Navarro, N; Sancho, C [Ciemat, Madrid (Spain); Angeles, A

    2000-07-01

    An adequate workplace monitoring must be carried out during the decommissioning activities, to ensure the protection of workers involved in these tasks. In addition, a large amount of waste materials are generated during the decommissioning of nuclear facilities. Clearance levels are established by regulatory authorities and are normally quite low. The determination of those activity concentration levels become more difficult when it is necessary to quantify alpha emitters such as uranium, especially when complex matrices are involved. Several methods for uranium determination in samples obtained during the decommissioning of a facility related to the first stage of the nuclear fuel cycle are presented in this work. Measurements were carried out by laboratory techniques. In situ gamma spectrometry was also used to perform measurements on site. A comparison among the different techniques was also done by analysing the results obtained in some practical applications. (Author)

  6. Nuclear minerals prospect ion activity report Period 1985-1987-Uranium prospect ion in Uranium; Informe sobre las actividades del Programa de prospeccion de minerales nucleares Periodo 1985 - 1987 Prospeccion de Uranio en el Uruguay

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1988-07-01

    In framework of Mineral Inventory and Nuclear minerals program in the article has been carried out the following aims: strategic level, synthesis and results reached, evaluation conclusions and trends.

  7. Measurement methodology of vegetable samples from an area affected by residual contamination due to uranium mining sterile; Metodologia de medida de muestras vegetales procedentes de un terreno afectado por contaminacion residual debida a esteriles de mineria de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Navarro, N.; Suarez, J. A.; Yague, L.; Ortiz Gandia, M. I.; Marijuan, M. J.; Garcia, E.; Ortiz, T.; Alvarez, A.

    2013-07-01

    This paper presents the methodology established for radiological characterization of plant material generated during the first stage of the realization of a movement of land in an area of land affected by residual contamination due to the burial of sterile of uranium mining. (Author)

  8. Calculations of received dose for different points in the enrichment uranium oxide warehouse at 4%; Calculos de dosis recibida para diferentes puntos en el almacen de oxido de uranio enriquecido al 4%

    Energy Technology Data Exchange (ETDEWEB)

    Alonso V, G. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    1990-06-15

    In order to verifying that the received dose so much inside as outside of the warehouse of enriched uranium dioxide to 4% it doesn't represent risk to the personnel, the modelling of this and the corresponding calculations for the extreme case of dose at contact are made. (Author)

  9. Dating by fission track method: study of neutron dosimetry with natural uranium thin films; Datacao com o metodo dos tracos de fissao: estudo da dosimetria de neutrons com filmes finos de uranio natural

    Energy Technology Data Exchange (ETDEWEB)

    Iunes, P J

    1990-06-01

    Fission track dating is described, focalizing the problem of the decay constant for spontaneous fission of {sup 238} U and the use of neutron dosimetry in fission track analysis. Experimental procedures using thin films of natural uranium as neutron dosimeters and its results are presented. The author shows a intercomparison between different thin films and between the dosimetry with thin film and other dosimetries. (M.V.M.). 52 refs, 12 figs, 9 tabs.

  10. Uranium hexafluoride reconversion used for dispersion fuel elements fabrication for IEAR-1/SP reactor; Reconversao de hexafluoreto de uranio para a fabricacao de combustiveis na forma de dispersoes para o reator IEA-R1/SP

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, E.F. Urano de; Lainetti, P.E.; Gomes, R.P. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

    1996-07-01

    In this paper are described the main chemical process employed in the Chemical Processes Division of the Fuel Technology Department - IPEN for conversion of enriched UF{sub 6} in ammonium diuranate - DUA and uranium tetrafluoride - UF{sub 4}. These activities have assured the continuity of fuel elements production at IPEN since 1984. The uranium recovery from scraps of the fuel elements production and the purification processes are also described. Those compounds are important intermediate products in the fabrication routine and in development dispersed fuel elements with higher uranium loading for IEA{sub R}1 research reactor power increase program. (author)

  11. Advances of the low enriched uranium utilization project in CNA-1 during 1998 and 1999; Avances del proyecto de utilizacion de uranio levemente enriquecido en la CNA-I en 1998 y 1999

    Energy Technology Data Exchange (ETDEWEB)

    Fink, Jose M; Higa, Manabu; Sidelnik, Jorge I [Nucleoelectrica Argentina SA (NASA), Buenos Aires (Argentina); Perez, Ramon A [Nucleoelectrica Argentina SA (NASA), Lima (Argentina). Central Nuclear Atucha I; Casario, Jose A; Alvarez, Luis A [Comision Nacional de Energia Atomica, San Martin (Argentina). Centro Atomico Constituyentes

    1999-07-01

    In this work, a general description of advances of the Enriched Fuel Introduction Project in CNA-1 and the main tasks performed during 1998 and 1999 are presented. The program is being satisfactorily developed and during that period the number of slightly enriched fuels (LEU) introduced had significantly increased in relation to previous years. At present, there are 181 LEU fuel elements in the core and 125 LEU fuel elements have been extracted. The number of full power burnt fuel elements per day decreased from 1.31 FE/dpp in 1994 (when all fuel was natural) to 0.92 in 1998 and 0.83 in 1999, reaching the predicted value for homogeneous LEU core of 0.7. The cost of burnt fuel in 1998 was 25% lower that if only natural fuel would have been used. (author)

  12. Rare earth elements and uranium in groundwater under influence of distinct aquifers in Campinas, SP, Brazil; Elementos terras raras e uranio em aguas subterraneas sob influencia de aquiferos distintos em Campinas (SP)

    Energy Technology Data Exchange (ETDEWEB)

    Bulia, Isabella Longhi; Enzweiler, Jacinta, E-mail: isabellalonghi@ige.unicamp.br, E-mail: jacinta@ige.unicamp.br [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Instituto de Geociencias

    2015-07-01

    The composition of groundwaters results mainly from water-rock reactions within aquifers. Among the various constituents of water, the rare earth elements (REE) and uranium can serve as tracers of geochemical processes and hydrological flow paths. The main objective of this study was to associate the chemical composition of groundwaters extracted from three distinct aquifer systems (crystalline, diabase and sedimentary) with that of the respective hosts rocks. The area of the study is located at the campus of University of Campinas (Campinas, SP). Samples of groundwater collected from four tubular wells were used to determine physicochemical parameters, major ions and trace elements, including the REE. The results confirm that the water of two wells (IMECC and IB) is predominantly influenced by the crystalline and diabase aquifers, while the other two (GM and FEF) by the sedimentary aquifer. Both the individual and normalized REE values of the four wells are distinct from each other, pointing to the heterogeneity of the local geology. The uranium concentration in the water of one well (GM) exceeded the guideline value for this element in drinking water. The U probably results from the oxidative dissolution of U-bearing phases in the sedimentary aquifer. However, the hydrochemical modeling indicated Ca{sub 2}UO{sub 2}(CO{sub 3}){sub 3} and CaUO{sub 2}(CO{sub 3}){sub 2}{sup 2-} as the major U dissolved species, which are considered non-toxic and non-bioavailable according to literature data. (author)

  13. Uranium and radium activities in samples of aquifers of the main cities of the Estado de Chihuahua; Actividades de uranio y radio en muestras de agua subterranea de las principales ciudades del Estado de Chihuahua

    Energy Technology Data Exchange (ETDEWEB)

    Villalba, L.; Colmenero S, L.; Montero C, M.E. [CIMAV, Av. Miguel de Cervantes Saavedra 120, 31109 Chihuahua (Mexico)]. e-mail: lourdes.villalba@cimav.edu.mx

    2003-07-01

    The natural uranium is in four valence states +3, +4, +5 and +6 being the hexavalent state the more soluble, which plays an important role in the transport of the uranium in the environment. The high concentrations of uranium in water not only in near waters to uranium mines, but also are in some mineral waters or in waters that are extracted of deep wells as it happens in the State of Chihuahua, where the underground waters are the fundamental source of consumption. The radium is a disintegration product of the uranium, the radio content in water is considered the second source of natural radioactivity. The distribution of radium in water is in function of the uranium content present in the aquifer. It was determined the uranium and radium content in samples of underground water of the main cities of the State of Chihuahua according to their number of inhabitants. The extraction methods for uranium and sulfates precipitation of Ba-Ra by means of the addition of barium carriers for the radium were used. The measures of the activities of uranium and radium were carried out by means of a portable liquid scintillation detector trade mark Thiathler-OY HIDEX. The obtained results have demonstrated that the content of uranium and radium in dissolution are in most of the sampling wells above the permissible maximum levels that manage the Mexican regulations. The high contents of uranium and radio can be attributed since to the influence of the geologic substrate characteristic of the zone in the State of Chihuahua they exist but of 50 uranium deposits. (Author)

  14. Solvent. I. Extraction systems applied to uranium analysis. I. Extraction studies with Tributyl phosphate-Methyl-isobutyl-ketone; Metodos de extraccion don disolventes aplicados al analisis quimico del uranio. I. Estudio de la extraccion con fosfato de tributilo-metilisobutilcetano

    Energy Technology Data Exchange (ETDEWEB)

    Vera Palomino, J; Palomares Delgado, F; Petrement Eguiluz, J C

    1964-07-01

    A factorial study of the selective extraction of uranium with a mixture of TBP-MIC was carried out using 0,8 N nitric acid and different salting agents. We use the most suitable salting agent to develop new factorial experiments in order to get an equation involving the percent of extracted uranium, E, the concentration of the extraction agent in the organic phase, c, and the concentration of the slating agent in the aqueous phase, n. (Author) 3 refs.

  15. Suporte articulado para o tratamento cirúrgico da escoliose: nota prévia Soporte articulado para el tratamiento quirúrgico de la escoliosis: nota previa Support for surgical treatment of scoliosis: foreword

    Directory of Open Access Journals (Sweden)

    Francisco Limeira dos Santos Neto

    2009-03-01

    Full Text Available Foi desenvolvido um suporte para ser utilizado nas cirurgias de correção da escoliose que permite a realização de manobras para a correção da deformidade. O objetivo deste relato inicial é a apresentação do conceito do suporte desenvolvido e os resultados iniciais com a sua utilização.Fue desarrollado un soporte para ser utilizado en las cirugías de corrección de la escoliosis. El soporte desarrollado permite la realización de maniobras para la corrección de la deformidad y el objetivo de este relato inicial es la presentación del concepto del soporte desarrollado y los resultados iniciales con su utilización.One support was developed for use in surgery for correction of scoliosis. This support allows the execution of surgery for the correction of the deformity, and the initial purpose of this report is the presentation of the concept support development and the initial results with its use.

  16. Persistencia de las ideas previas sobre potencial eléctrico, intensidad de corriente y ley de Ohm en los estudiantes de segundo curso de Ingeniería

    OpenAIRE

    Periago Oliver, María Cristina; Bohigas Janoher, Xavier

    2005-01-01

    El objetivo del trabajo que se presenta es la evaluación y el análisis de los conocimientos previos sobre los contenidos conceptuales de Teoría de circuitos que tienen los alumnos de segundo curso de Ingeniería Industrial e Ingeniería Química, con la finalidad de detectar la persistencia de estos conocimientos desde niveles educativos anteriores. Concretamente, nos hemos centrado en los conceptos básicos de potencial eléctrico e intensidad de la corriente, así como la relación fundamental ent...

  17. Territorialidad y autonomía, proyectos minero-energéticos y consulta previa: el caso de los pueblos indígenas de la Amazonía ecuatoriana

    Directory of Open Access Journals (Sweden)

    Fernando García Serrano

    2014-07-01

    Full Text Available From the review of two areas of relative state / indigenous peoples, territoriality, mining and energy projects and consultation, is to analyze the progress, setbacks and dissections lived in this relationshipduring the period 1990-2013, to contribute to the discussion of this problem in other countries experiencing similar circumstancesin Latin America. Of particular importance is the case of Ecuador to the constitutions of 1998 and 2008, in which the multiethnic and multicultural nature of the Ecuadorian State acknowledged at the first, and the plurinational and intercultural character in the second. Likewise, the indigenous movement since its emergence as an actor in national politics since 1990, has not only been a pioneer and leader in the region, but has been challenger extractivismo process carried outby the state.

  18. La Investigación Básica. La Investigación en Ciencias Fisiológicas: Bioquímica, Biología Molecular y Fisiología. Cuestiones Previas

    Directory of Open Access Journals (Sweden)

    Constancio González Martínez

    Full Text Available La conferencia impartida los últimos días de enero de 2004 en las Dependencias del Instituto Carlos III (Madrid ante un grupo de colegas latinoamericanos, y que transcribo en el escrito que sigue, ha tenido como objetivo fundamental tratar de conjugar algunas ideas sobre investigación con la realidad socioeconómica de los países de Latinoamérica. En la primera parte de la conferencia he dado un concepto de Investigación y he enfatizado el valor que la consideración de la teleología de los fenómenos biológicos tiene en el avance de las propias ciencias biológicas. A continuación, he pasado revista de forma muy rápida a las Normas del Bien Hacer en le Laboratorio o Good Laboratory Practices, y he presentado unos pocos datos objetivos sobre la realidad económica de los países latinoamericanos. En una segunda parte, he tratado de promover en nuestros colegas latinoamericanos una actitud reivindicativa que les ayude a pedir a sus gobernantes y a defender frente a sus conciudadanos, la necesidad de implementar una política científica clara como una prioridad nacional. Tal reivindicación estaría apoyada en el reconocimiento de que la investigación es una herramienta para aprovechar la capacidad intelectual de los ciudadanos de cada país, de que la investigación es un medio para aprovechar recursos de organismos internacionales, de que la investigación es una fuente de cultura que contribuye a la creación de una identidad nacional y, finalmente, de que la investigación es una actividad generadora de riqueza y bienestar. Concluyo la conferencia señalando que la investigación básica, y por tanto la investigación en Ciencias Fisiológicas, está ensamblada tan estrechamente con la investigación aplicada que constituyen una realidad única.

  19. Efecto de la presión ambiental en la efectividad del lanzamiento al aro y la ansiedad previa a la ejecución en basquetbolistas principiantes y avanzados

    Directory of Open Access Journals (Sweden)

    Guadalupe Delgado Socatelli

    2003-01-01

    Full Text Available Con el objetivo de determinar si las condiciones de presión ambiental dadas por: el tiempo de ejecución, y la ausencia o presencia de público afectaban el rendimiento de 10 jugadores de baloncesto principiantes y 10 jugadores avanzados al ejecutar 10 tiros libres al aro lo cual permitiría conocer los cambios en la ansiedad grupal e individual de los participantes mediante la aplicación de los instrumentos POMS de McNair, Loor y Droppleman (1971 y el CSAI-2 de Martens y Vealey (1990. El análisis estadístico se efectuó mediante la aplicación de un ANOVA de medidas repetidas para buscar diferencias entre los intentos según el tipo de presión. La determinación de las diferencias entre grupos, entre las mediciones, según el nivel de presión ambiental, y la interacción de la presión de los grupos, se hizo mediante la aplicación de un ANOVA Factorial Mixto. Los resultados de la investigación permitieron corroborar la individualidad de las respuestas de la ansiedad ante distintas situaciones y la importancia de la personalización del afrontamiento para el manejo de la ansiedad competitiva

  20. Evaluación higiénica previa de acrilamida en aire durante la preparación de gel de poliacrilamida (PAA en un laboratorio de genética

    Directory of Open Access Journals (Sweden)

    Antonio Blein Sánchez de León

    2007-06-01

    Full Text Available Objetivos: Conocer el nivel aproximado de concentración en aire de Acrilamida, cancerígeno y mutagénico tipo 2, durante la preparación del gel de Poliacrilamida en el Laboratorio, para verificar si la situación higiénica es tolerable, o si no lo es, para tomar medidas preventivas inmediatamente, antes de llevar a cabo una evaluación detallada con arreglo a UNE-EN 689, con un coste notablemente mayor. Metodología: Una vez seleccionadas las etapas de preparación del gel donde hay emisión de Acrilamida, el método higiénico seguido ha sido el PV2004, de NIOSH, para la toma de muestra y el análisis. Resultados: La concentración de Acrilamida detectada en la fase de pesada es de 723% del Valor Limite de Exposición Profesional para exposición diaria y del 145% del Valor Limite de Exposición Profesional para Corta Exposición. En la fase de agitación no se detecto Acrilamida en la muestra. Conclusiones: Es necesario tomar medidas preventivas inmediatamente. Se proponen varias medidas. Una vez aplicadas, se recomienda realizar la evaluación higiénica según UNE-EN 689.Aims: To know the approximate level of Acrylamide, carcinogenic type 2, in air, during the preparation of Polyacrylamide-Gel in the laboratory, in order to determine if the occupational hygiene situation is acceptable or not, in order to, if not, to implement immediately preventive measurements, before carring out an hygienical assessment following the UNE-EN 689 standard, with much higher costs. Methods: After the selection of the gel-preparation stages, where evaporation of Acrylamide takes place, the followed method was PV2004, from NIOSH, for the sample collection and for the analyse. Results: The detected level of Acrylamide in the weighting stage is 723 % of the TLV-TWAand 145% of the TLV-C. In the stirring stage there was found no Acrylamide. Conclusions: It is necessary to implement immediately preventive measurements. Some of them are proposed. Once implemented it is recommended to carry out an hygienical assessment according to UNE-EN 689.

  1. Pocket book {sup E}xpectations of operating personnel action and card criteria, previous meeting and precursor of error; Libro de bolsillo expectativas de actuacion del personal de operacion y tarjeta criterios reunion previa y precursores de error

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigo Gonzalez, M.

    2012-07-01

    We have developed a pocket manual of performance expectations of operating personnel. Additionally, it has created a card pocket systematizing the application of previous meetings (pre-job) depending on the existence of error precursors and following the commission of an error. This manual serves to communicate expectations and performance expected to the Operation Staff. The results show a positive change in a short period of time working practices, both in training (simulator) and control room.

  2. Case report

    African Journals Online (AJOL)

    abp

    2015-05-18

    May 18, 2015 ... Abstract. Vasa previa is a rare but clinically important obstetrical complication that can be associated with a low-lying placenta or placenta previa. We aim to present one case of vasa previa diagnosed during the placenta examination after the caesarean indicated for triple uterus scar. A 26-year-old.

  3. A representação social do risco “urânio empobrecido”

    Directory of Open Access Journals (Sweden)

    Bruna ZANI

    2012-08-01

    Full Text Available Negli ultimi decenni, ambientalisti, giornalisti, politici e parte dell?opinione pubblica si sono schierati contro l?uso dell?uranio impoverito nelle munizioni e nelle corazzature difensive, chiamando in causa gli effetti potenziali nocivi sulla salute. Ma quali informazioni e conoscenze hanno le persone comuni? Per ovviare ai limiti del paradigma psicometrico, che si è focalizzato prevalentemente sui processi cognitivi trascurando il contesto sociale nel quale la persona è inserita, il presente studio si è proposto di esplorare il contenuto e il campo delle rappresentazioni sociali del rischio ?uranio impoverito?. Si è fatto ricorso alla tecnica delle associazioni libere, chiedendo ai partecipanti (N= 1158, età media 26.7 anni, DS = 11.04, 42% uomini, con diverso orientamento politico di esprimere fino a 3 parole pensando a ?uranio impoverito? e di valutarne la positività/negatività su scala a cinque punti da 1 (molto positiva a 5 (molto negativa. Le analisi condotte sia mediante l?analisi del contenuto tematica che l?analisi delle corrispondenze lessicali hanno evidenziato l?organizzazione delle rappresentazioni intorno a differenti nuclei tematici, a carattere prevalentemente negativo: malattia/mortalità,, armi e guerra, catastrofe e esplosione atomica. Sono emerse inoltre differenze interessanti nelle rappresentazioni in base al genere, all?età e all?orientamento politico dei partecipanti: le persone più anziane sono più informate e consapevoli, associano termini carichi emotivamente, evocatori anche di un alone di colpevolezza intorno alla ?faccenda? dell?uranio impoverito. I giovanissimi invece, poco più che bambini quando il caso uranio impoverito è esploso all?attenzione delle cronache, sono meno esposti alle informazioni e fanno riferimenti a immagini quali bomba atomica e disastro nucleare. Coerentemente con l?effetto dell?uomo bianco, le donne tendono a riportare una maggiore percezione dei rischi associati all?uranio

  4. Geochemical behaviour of uranium and thorium in the waste of a uranium conversion facility

    OpenAIRE

    Fernandes, Teresa

    2017-01-01

    Los residuos contenidos en las balsas de decantación de la planta de conversión de uranio de Comurhex - Malvési, Francia, han sido caracterizados con el objectivo de investigar el comportamiento de uranio y torio en este entorno específico. El residuo es una sucesión de estratos heterogénea que comprende una mezcla de los efluentes del proceso con el suelo (que han tenido su origen en la re-construcción de los diques de las balsas, el efluente de lodo, y los antiguos desechos d...

  5. Pulsed-Source Experiments with Multiplying and Non-Multiplying Heavy Water Systems; Experiences a l'Aide de Sources Pulsees sur des Systemes Multiplicateurs et Non Multiplicateurs a Eau Lourde; Ehksperimenty s pul'siruyushchim istochnikom na nerazmnozhayushchikh i razmnozhayushchikh ustrojstvakh s tyazheloj vodoj; Experimentos con Fuentes Pulsadas en Sistemas de Agua Pesada Multiplicadores y No Multiplicadores

    Energy Technology Data Exchange (ETDEWEB)

    Utzinger, E.; Heer, W.; Lutz, H. R. [Swiss Federal Institute for Reactor Research, Wuerenlingen (Switzerland)

    1965-10-15

    paralleles de diverse dimension, en nombres differents. Les auteurs ont mesure le flux de neutrons thermiques variable dans le temps pour chaque systeme a differentes positions axiales en vue d'obtenir les constantes de decroissance des modes de neutrons instantanes pour differents laplaciens axiaux (analyse de Fourier) sans modifier la hauteur du niveau de D{sub 2}O. Ils ont compare les valeurs experimentales avec les parametres obtenus a l'aide d'une theorie a deux groupes. Ils discutent les limitations de la technique. En outre, ils ont mesure directement la reactivite dans des systemes fortement sous-critiques ou p Greater-Than-Or-Equal-To -40$ en utilisant la queue des bouffees constituee par des neutrons retardes. Enfin, ils comparent les resultats avec ceux de mesures statiques et montrent qu'ils sont en assez bon accord. (author) [Spanish] Los autores utilizaron la instalacion subcritica ' MINOR' del Eidgenoessisches Institut fuer Reaktorforschung de Wuerenlingen para una larga serie de mediciones con una fuente de neutrones pulsados utilizando la reaccion {sup 3}T(d, n){sup 4}He. Llevaron a cabo tres clases de experimentos a fin de medir: 1. Las constantes de decrecimiento de los modos correspondientes a los neutrones instantaneos en reticulados de uranio natural y ligeramente enriquecido. 2. La reactividad en el estado subcritico, partiendo del decrecimiento de los neutrones instantaneos y de los datos proporcionados por las 'colas' de neutrones retardados en reticulados de uranio natural y ligeramente enriquecido. 3. La anisotropia de la constante de difusion termica en D{sub 2}O previa introduccion de un numero variable de tubos paralelos de diversos tamaflos. Se midio el flujo de neutrones termicos en funcion del tiempo en cada uno de los sistemas con distintas posiciones del eje, a fin de obtener las constantes de decrecimiento de los modos de los neutrones instantaneos para distintos laplacianos axiales (analisis de Fourier) sin modificar el nivel real del D

  6. Behaviour of the pH adjustment, Ion exchange and concentrate precipitation stages in the acid leaching of uranium phosphate ores; Tratamiento de disoluciones de lixiviacion de minerales de uranio en presencia de fosfatos. Comportamiento en las etapas de ajuste de PH, cambio de ion y precipitacion de concentrados

    Energy Technology Data Exchange (ETDEWEB)

    Estrada Aguilar, J; Uriarte Hueda, A

    1962-07-01

    The uranium recovery from acid leach solutions of uranium-phosphate ores has been studied. Relations have been found between the solution characteristics and the results obtained at different stages of the process. The following data can thus be predicted: solids to remove and uranium recovery in the pH adjustment stage, uranium capacity of the resin, more suitable eluating agent, elution velocity and uranium concentration in the eluate in the ion exchange stage, and composition of the concentrate produced by direct precipitation of the eluate in the concentrate precipitation stage. (Author) 8 refs.

  7. Temporal behavior of {sup 222}Radon, {sup 226}Radium and {sup 238}Uranium in deep water wells which provide Valle de Toluca with drinking water; Comportamiento temporal de {sup 222}Radon, {sup 226}Radio y {sup 238}Uranio en pozos profundos que abastecen de agua potable al Valle de Toluca

    Energy Technology Data Exchange (ETDEWEB)

    Pena, P; Tamez, E; Iturbe, J L; Acosta, A; Segovia, N [Instituto Nacional de Investigaciones Nucleares, Mexico City (Mexico); Carrillo, J; Armienta, M [Universidad Nacional Autonoma de Mexico, Mexico City (Mexico). Inst. de Geofisica

    1994-12-31

    The presence of radionuclides in underground waters may be an indication of its origin and also the sign of the hydraulic properties of the aquifers layers where circulate. Additionally, the ingestion by human beings of water with radioactive elements (Radon 222, Radium 226, Uranium 238) can give as a result the accumulation of such elements in several organs of the body producing then health damages. In this work, the concentrations of Radon 222, Radium 226 and Uranium 238, in waters coming from deep wells which provide with drinking water the Toluca Valley, were determined. For this purpose, during a year (june 1991 to August 1992) ten wells were sampled with a tracking of the radionuclides concentration as well as the physical-chemical components of water; it was established the relationship presented by the analyzed waters with the local geology and the local and regional systems. (Author).

  8. Development of an analytical method for the direct determination of uranium isotopes in occupationally exposed personnel urine samples using Icp-SFMS; Desarrollo de un metodo analitico para la determinacion directa de isotopos de uranio en muestras de orina de personal ocupacionalmente expuesto (POE) usando ICP-SFMS

    Energy Technology Data Exchange (ETDEWEB)

    Torres C, C. O.; Hernandez M, H.; Romero G, E. T. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Vega C, H. R., E-mail: hector.hernandez@inin.gob.mx [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98060 Zacatecas, Zac. (Mexico)

    2016-09-15

    The development of an analytical method for measuring actinides in radioactive waste, environmental and biological samples has been a major challenge in institutions dedicated to the nuclear sector. Is for this reason that the developed and validated methods to measure isotopes of elements belonging to the actinide family have as main objective the characterization of radioactive wastes, the monitoring of radioactive installations and the dosimetric evaluation of occupationally exposed personnel, this for the purpose to prevent incidents or radiological accidents and to safeguard workers. This research work is focused on determining isotopes of uranium (U) and obtaining isotope ratios in urine samples of occupationally exposed personnel using a Magnetic Sector Mass Spectrometer with Inductively Coupled Plasma Source (Icp-SFMS), which is a versatile and promising technique for a large number of applications. The urine samples are acidified in order to favor the dissolution of the analytes in the samples, minimizing as much as possible their loss by sorption in the walls of the sampling bottle. For the determination of U in urine samples, dilution was performed, taking 2 ml of the urine samples and weighing it to 100 ml with 2% ultra pure HNO{sub 3} and finally performing the measurement by Icp-SFMS. The results obtained in the measurements of U show an order of magnitude in terms of sensitivity offered by Icp-SFMS. The isotopic ratios {sup 234}U/{sup 238}U, {sup 235}U/{sup 238}U are very close to the results reported by the literature and the quantification of the isotopes of said element show be within the concentration range of U, indicating that is exposed to depleted U. Additionally, Limit of Detection and Quantification Limit calculations were performed, which are of the order of pg mL{sup -1}. (Author)

  9. Study of the temperature influence during the uranium (Vi) sorption on surface of ZrP{sub 2}O{sub 7} in presence of oxalic and salicylic acid; Estudio de la influencia de la temperatura durante la sorcion de uranio (VI) en la superficie del ZrP{sub 2}O{sub 7} en presencia de acidos oxalico y salicilico

    Energy Technology Data Exchange (ETDEWEB)

    Garcia G, N.

    2013-07-01

    This work studies the effect of temperature on the uranium (Vi) sorption onto zirconium diphosphate in the presence of organic acids (oxalic and salicylic acids). Zirconium diphosphate was synthesized by a chemical condensation reaction and characterized using several analytical techniques, in order to check its purity. This point is very important because the presence of any impurities or secondary phases may interfere with the hydration and sorption process. Prior to the sorption experiments, three batches of zirconium diphosphate were pre-equilibrated with NaClO{sub 4}, oxalic acid or salicylic acid solutions. The hydrated solids were washed and dried and then again characterized in order to study the interactions between organic acids and zirconium diphosphate surface. Uranium sorption onto zirconium diphosphate (pre-equilibrated with NaClO{sub 4}, oxalic acid and salicylic acid solutions) was investigated as a function of ph, organic acid and temperature (20, 40 y 60 grades C). Thermodynamic parameters for the sorption reactions (enthalpy change, entropy change and Gibbs free energy change) were determined from temperature dependence of distribution coefficient by using the Vant Hoff equation. Solids characterization after hydration shows that exist an interaction between organic acids and ZrP{sub 2}O{sub 7}. This fact was confirmed with the microcalorimetry study, the reaction heat for hydration of zirconium diphosphate in NaClO{sub 4} solution was exothermic (-269.59 mJ) and for hydration of zirconium diphosphate in oxalic acid solution was endothermic (53.64 mJ). The experimental results showed important differences in the sorption mechanisms for the reaction of Uranium with ZrP{sub 2}O{sub 7} in the presence and absence of organic acids. For the zirconium diphosphate hydrated with oxalic acid, the sorption percentage was 50% from lowest ph values. For the zirconium diphosphate hydrated with salicylic acid, the initial concentration of uranium was 6 x 10{sup -4} M and a percentage of 10% was observed in the initial reaction and it reached 100% at ph 5.5. A similar behavior was observed for the zirconium diphosphate hydrated with NaClO{sub 4}, but the initial concentration of uranium was 5 x 10{sup -4} M. The temperature had an important effect on the sorption of uranium onto ZrP{sub 2}O{sub 7}. The reaction of uranium with the solid hydrated with NaClO{sub 4} was exothermic from 20 to 60 grades C, and the reaction with the solid hydrated with organic acids was exothermic from 20 to 40 grades C and endothermic from 40 to 60 grades C. In conclusion, the thermodynamic study indicated that the sorption process was activated chemisorption s. (Author)

  10. Application of the probe Horiba U-23 in the analysis of physical-chemical parameters of groundwater influences on the Osamu Utsumi uranium mine in Caldas-MG; Aplicacao da sonda Horiba U-23 na analise de parametros fisico-quimicos das aguas subterraneas sobre influencia da mina de uranio Osamu Utsumi em Caldas-MG

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Flavio H.S., E-mail: flaviohsmoreira2@gmail.com [Universidade Federal de Alfenas (UNIFAL), Pocos de Caldas, MG (Brazil); Alberti, Heber L.C.; Silva, Nivaldo C., E-mail: heber@cnen.gov.br, E-mail: ncsilva@cnen.gov.br [Comissao Nacional de Energia Nuclear (LAPOC/CNEN-MG), Pocos de Caldas, MG (Brazil). Laboratorio de Pocos de Caldas; Fleming, Peter Marshall, E-mail: pmf@cnen.gov.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, BH (Brazil)

    2013-07-01

    This study presents data on the analysis of physical-chemical parameters of groundwater in the uranium mine Osamu Utsumi, belonging to the Industrias Nucleares do Brasil - INB, in the municipality of Caldas. This work is part of the team responsible for the evaluation of Plano de Recuperacao de Areas Degradadas (PRAD), team consists of researchers from Laboratorio de Pocos de Caldas - LAPOC and of the Centro de Desenvolvimento Tecnologico Nuclear - CDTN, units of the Comissao Nacional de Energia Nuclear - CNEN. Sampling was carried out in eleven wells in the 'bota-fora 4' area and digs mine. Analyses of groundwater quality were performed using the multiparameter probe Horiba U23, recent acquisition of LAPOC. The results characterize the groundwater of ten wells monitored as acidic and with a high electrical conductivity, due to the impacts caused by drainage Mining Acid (DAM)

  11. Determination {sup 230}Th by ICP-MS for the control of activities of restoration of an area of land contaminated with uranium mining sterile; Determinacion de {sup 230}Th mediante ICP-MS durante el control de las actividades de restauracion de un area de terreno contaminada con esteriles de mineria de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Yague, L.; Conde, E.; Navarro, N.; Fernandez, M.; Ortiz, M. I.; Noguerales, C.; Gasco, C.

    2013-07-01

    In 2012, within the activities for the Project PIMIC (CIEMAT) took out the first stage of restoration of a contaminated area. This is an area which had a residual contamination due to burial tailings uranium mining. The activities have been: elimination of the arboreal mass, excavation of the ground and earthmoving. The methodology applied is described in this work and is based on the combination of gamma spectrometry technique and development of a method of analysis {sup 230}Th by ICP-MS. (Author)

  12. Statistic analysis of grouping in evaluation of the behavior of stable chemical elements and physical-chemical parameters in effluent from uranium mining; Analise de agrupamento na avaliacao do comportamento de elementos quimicos estaveis e parametros fisico-quimicos em efluente de mineracao de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Wagner de S., E-mail: wspereira@inb.gov.br, E-mail: pereirarsj@gmail.com [Universidade Federal Fluminense (GETA/LARARA-PLS/UFF), Niteroi, RJ (Brazil). Grupo de Estudos em Temas Ambientais. Laboratorio de Radiobiologia e Radiometria Pedro Lopes dos Santos; Py Junior, Delcy de A.; Dores, Luis A. de C.B.; Campelo, Emanuele L.C.; Morais, Gustavo F. de; Kelecom, Alphonse, E-mail: delcy@inb.gov.br, E-mail: kclecom@uol.com.br [lndustrias Nucleares do Brasil (UTM/INB), Pocos de Caldas, MG (Brazil). Unidade de Tratamento de Minerios; Pereira, Juliana R. de S., E-mail: pereirarsj@gmail.com [Universidade Federal de Alfenas, Pocos de Caldas, MG (Brazil)

    2013-10-01

    The Ore Treatment Unit (UTM) is a uranium mine off. The statistical analysis of clustering was used to evaluate the behavior of stable chemical elements and physico-chemical variables in their effluents. The use of cluster analysis proved effective in the evaluation, allowing to identify groups of chemical elements in physico-chemical variables and group analyzes (element and variables ). As a result, we can say, based on the analysis of the data, a strong link between Ca and Mg and between Al and TR{sub 2}O{sub 3} (rare earth oxides) in the UTM effluents. The SO{sub 4} was also identified as strongly linked to total solids and dissolved and these linked to electrical conductivity. Other associations existed, but were not as strongly linked. Additional collections for seasonal evaluation are required so that assessments can be confirmed. Additional statistics analysis (ordination techniques) should be used to help identify the origins of the groups identified in this analysis. (author)

  13. Spectrographic determination of boron and silicon in uranium tetrafluoride: Study of the chemical reactions in the electrode cavity when ZnO is used as a uranium excitation suppressor; Determinacion espectrografica de Boro y Silicio en Tetrafluoruro de Unraio: Estudio de las reacciones quimicas que tienen lugar en el crater del electrodo al autilizar ZnO como supresor de la excitacion del Uranio

    Energy Technology Data Exchange (ETDEWEB)

    Alduan, F. A.; Capdevila, C.; Rosa, M.

    1973-07-01

    A method has been developed for determining traces of boron and silicon in uranium tetrafluoride. Use is made of zinc oxide to decrease the volatilization of uranium and achieve high sensitivities. The thermochemical reactions which occur in the anode cavity during the arcing process have been investigated. UO{sub 2} and a uranium, zinc and fluorine compound, both less volatile than uranium tetrafluoride, are formed. (Author)

  14. Determination of uranium and {sup 2}10Po in the river Odiel to assess the radioactive impact of acid mine drainage; Determinacion de uranio y {sup 2}10Po en el rio Odiel para valorar el impacto radiactivo de los drenajes acidos mineros

    Energy Technology Data Exchange (ETDEWEB)

    Manjon, G.; Lehritani, M.; Mantero, J.; Diaz Frances, I.; Garcia-Tenorio, R.

    2013-07-01

    Since 1986 this research group has been monitoring of radioactive environmental impact in the estuary of the river Odiel, generated by the factories of production of phosphoric acid from Huelva, that emitting NORM waste. Once closed factories, is observed a second source of contamination: mining drains. To verify this source have been studied concentration levels of natural radionuclides in the waters and sediments of the river Odiel, in areas that are incorporated drains. (Author)

  15. Determination of the isotopic ratio {sup 234} U/{sup 238} U and {sup 235} U/{sup 238} U in uranium commercial reagents by alpha spectroscopy; Determinacion de la relacion isotopica {sup 234} U/{sup 238} U y {sup 235} U/{sup 238} U en reactivos comerciales de uranio por espectrometria alfa

    Energy Technology Data Exchange (ETDEWEB)

    Iturbe G, J L

    1990-02-15

    In this work the determination of the isotope ratio {sup 234} U/{sup 238} U and {sup 235} U/{sup 238} U obtained by means of the alpha spectroscopy technique in uranium reagents of commercial marks is presented. The analyzed uranium reagents were: UO{sub 2} (*) nuclear purity, UO{sub 3} (*) poly-science, metallic uranium, uranyl nitrate and uranyl acetate Merck, uranyl acetate and uranyl nitrate Baker, uranyl nitrate (*) of the Refinement and Conversion Department of the ININ, uranyl acetate (*) Medi-Lab Sigma of Mexico and uranyl nitrate Em Science. The obtained results show that the reagents that are suitable with asterisk (*) are in radioactive balance among the one {sup 234} U/{sup 238} U, since the obtained value went near to the unit. In the case of the isotope ratio {sup 235} U/{sup 238} U the near value was also obtained the one that marks the literature that is to say 0.04347, what indicates that these reagents contain the isotope of {sup 235} U in the percentage found in the nature of 0.71%. The other reagents are in radioactive imbalance among the {sup 234} U/{sup 238} U, the found values fluctuated between 0.4187 and 0.1677, and for the quotient of activities {sup 235} U/{sup 238} U its were of 0.0226, and the lowest of 0.01084. Also in these reagents it was at the {sup 236} U as impurity. The isotope of {sup 236} U is an isotope produced artificially, for what is supposed that the reagents that are in radioactive imbalance were synthesized starting from irradiated fuel. (Author)

  16. Study on the preparation and stability of uranium carbide samples for the determination of oxygen, hydrogen and nitrogen by fusion under high vacuum; Estudio sobre la preparacion y estabilidad de las muestras de carburo de uranio para la determinacion de oxigeno, hidrogeno y nitrogeno por fusion en alto vacio

    Energy Technology Data Exchange (ETDEWEB)

    Perez Garcia, M

    1966-07-01

    In view of the high reactivity of uranium carbide, the method employed for the preparation of the sample for the analysis of its gas content: oxygen, hydrogen and nitrogen, has a decisive influence on the analytical results. The variation in the O{sub 2}, H{sub 2} and N{sub 2} content of the uranium carbide has been studied in this paper with the methods utilized for the sample preparation (grinding and cutting). (Author) 9 refs.

  17. Communication Received from France Concerning its Policies regarding the Management of Plutonium. Statements on the Management of Plutonium and of High Enriched Uranium; Comunicacion recibida de Francia en relacion con sus politicas referentes a la gestion del plutonio. Declaraciones sobre la gestion del plutonio y del uranio muy enriquecido

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-09-17

    The Director General has received a note verbale dated 24 August 2010 from the Permanent Mission of France to the IAEA in the enclosures of which the Government of France, in keeping with its commitment under the Guidelines for the Management of Plutonium (contained in INFCIRC/549 of 16 March 1998 and hereinafter referred to as the 'Guidelines'), and in accordance with Annexes B and C of the Guidelines, has made available annual figures for holdings of civil unirradiated plutonium and the estimated amounts of plutonium contained in spent civil reactor fuel as of 31 December 2009 [Spanish] El Director General ha recibido una nota verbal, de fecha 24 de agosto de 20010, de la Mision Permanente de Francia ante el OIEA, en cuyos anexos el Gobierno de Francia, en cumplimiento de su compromiso contraido en virtud de las Directrices para la gestion del plutonio (transcritas en el documento INFCIRC/549 de 22 de junio de 1998 y en adelante denominadas 'directrices') y, de conformidad con los Anexos B y C de las directrices, ha presentado las cifras anuales de sus existencias nacionales de plutonio no irradiado de uso civil y las cantidades estimadas de plutonio contenido en el combustible gastado de reactores de uso civil, al 31 de diciembre de 2009.

  18. Communication Received from France Concerning its Policies regarding the Management of Plutonium. Statements on the Management of Plutonium and of High Enriched Uranium; Comunicacion recibida de Francia en relacion con sus politicas referentes a la gestion del plutonio. Declaraciones sobre la gestion del plutonio y del uranio muy enriquecido

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-09-04

    The Director General has received a Note Verbale dated 17 July 2007 from the Permanent Mission of France to the IAEA in the enclosures of which the Government of France, in keeping with its commitment under the Guidelines for the Management of Plutonium (contained in INFCIRC/549 of 16 March 1998 and hereinafter referred to as the 'Guidelines'), and in accordance with Annexes B and C of the Guidelines, has made available annual figures for holdings of civil unirradiated plutonium and the estimated amounts of plutonium contained in spent civil reactor fuel as of 31 December 2006 [Spanish] El Director General ha recibido una nota verbal, de fecha 17 de julio de 2007, de la Mision Permanente de Francia ante el OIEA, en cuyos anexos el Gobierno de Francia, en cumplimiento de su compromiso contraido en virtud de las Directrices para la gestion del plutonio (contenidas en el documento INFCIRC/549 de 16 de marzo de 1998 y en adelante denominadas 'directrices') y, de conformidad con los anexos B y C de las directrices, ha presentado las cifras anuales de sus existencias nacionales de plutonio no irradiado de uso civil y las cantidades estimadas de plutonio contenido en el combustible gastado de reactores de uso civil, al 31de diciembre de 2006.

  19. Communication Received from France Concerning Its Policies regarding the Management of Plutonium. Statements on the Management of Plutonium and of High Enriched Uranium; Comunicacion recibida de Francia en relacion con sus politicas referentes a la gestion del plutonio. Declaraciones sobre la gestion del plutonio y del uranio muy enriquecido

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-12-29

    The Secretariat has received a note verbale dated 2 May 2013 from the Permanent Mission of Switzerland to the IAEA in the enclosures of which the Government of Switzerland, in keeping with its commitment under the Guidelines for the Management of Plutonium (contained in INFCIRC/549 of 16 March 1998 and hereinafter referred to as 'Guidelines') and in accordance with Annexes B and C of the Guidelines, has made available annual figures for its holdings of civil unirradiated plutonium and the estimated amounts of plutonium contained in spent civil reactor fuel as of 31 December 2012 [Spanish] El Director General ha recibido una nota verbal, de fecha 13 de noviembre de 2006, de la Mision Permanente de Francia ante el OIEA, en cuyos anexos el Gobierno de Francia, en cumplimiento de su compromiso contraido en virtud de las Directrices para la gestion del plutonio (contenidas en el documento INFCIRC/549 de 22 de junio de 1998 y en adelante denominadas 'directrices') y, de conformidad con los anexos B y C de las directrices, ha presentado las cifras anuales de sus existencias nacionales de plutonio no irradiado de uso civil y las cantidades estimadas de plutonio contenido en el combustible gastado de reactores de uso civil, al 31 de diciembre de 2005.

  20. Method for determining microamounts of uranium in solutions from copper ores, by liquid-liquid extraction and spectrophotometry with arsenazo III.; Metodo para determinar microcantidades de uranio en disoluciones de minerales de cobre, por extraccion liquido-liquido y espectrofotometria con arsenazo III

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, B.

    1972-07-01

    A spectrophotometric method is described for determining small amounts of uranium in aqueous solutions from copper ores. Uranium is quantitatively separated in a single extraction by a solution of tri-n-octylphosphine oxide in benzene, using ethylendiaminetetracetic acid and sodium fluoride as complexing agents, for improving the selectivity of the procedure. An aliquot of the extract is diluted with a hydrocolloidal solution of arsenazo III. Optical density is measured at 650 nm. (Author) 3 refs.

  1. Nondestructive analysis of the natural uranium mass through the measurement of delayed neutrons using the technique of pulsed neutron source; Analise nao destrutiva da massa de uranio natural atraves da medida de neutrons atrasados com o uso da tecnica de fonte pulsada de neutrons rapidos

    Energy Technology Data Exchange (ETDEWEB)

    Coelho, Paulo Rogerio Pinto

    1979-07-01

    This work presents results of non destructive mass analysis of natural uranium by the pulsed source technique. Fissioning is produced by irradiating the test sample with pulses of 14 MeV neutrons and the uranium mass is calculated on a relative scale from the measured emission of delayed neutrons. Individual measurements were normalised against the integral counts of a scintillation detector measuring the 14 MeV neutron intensity. Delayed neutrons were measured using a specially constructed slab detector operated in anti synchronism with the fast pulsed source. The 14 MeV neutrons were produced via the T(d,n) {sup 4}He reaction using a 400 kV Van de Graaff accelerated operated at 200 kV in the pulsed source mode. Three types of sample were analysed, namely: discs of metallic uranium, pellets of sintered uranium oxide and plates of uranium aluminium alloy sandwiched between aluminium. These plates simulated those of Material Testing Reactor fuel elements. Results of measurements were reproducible to within an overall error in the range 1.6 to 3.9%; the specific error depending on the shape, size and mass of the sample. (author)

  2. Data integration from gamma radiation decay from uranium: a case-study in the region of Santa Maria, Rio Grande do Sul-Brazil;Integracao de dados de decaimento radiometrico de uranio: estudo de caso na regiao de Santa Maria (RS)

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Joao Eduardo; Silva, Jose Luiz Silverio da; Pires, Carlos Alberto, E-mail: jesp61@gmail.co, E-mail: silverio@smail.ufsm.b, E-mail: calpires@base.ufsm.b [Universidade Federal de Santa Maria (CCNE/UFSM), RS (Brazil). Centro de Ciencias Naturais e Exatas. Dept. de Geociencias; Strieder, Adelir Jose, E-mail: adelir@ufrgs.b [Universidade Federal do Rio Grande do Sul (DEM/UFRGS), Porto Alegre, RS (Brazil). Dept. de Engenharia de Minas

    2008-09-15

    This work consists of data integration of uranium concentrations, parts per million (ppm), associated to the different rock formations belonging to Parana Basin in the region of Santa Maria, in the Rio Grande do Sul state southern Brazil. This study was developed from primary data generated by the Companhia de Pesquisas de Recursos Minerais as part of the AERO/Camaqua; Project, 1010 code series, digitalized in the 1997 Geosoft XYZ format. Through an irregular net of values of uranium concentration, with 25806 observations were spatially oriented by Universal Transverse Mercator/ UTM coordinates. Which were varied from west to east 206190 to 276813 E, and from north to south 6670888 to 6735665 N, totalizing an area of 4574.75 km{sup 2}. Using Statistica 7.1 software licensed to the Department of Statistics at the Federal University of Santa Maria, the mean values of and the confidence limits with alpha = 0.05, the standard deviations of uranium concentrations for each rock formation. The comparisons between the mean values were made through the Tuckey's Test and the spatial variation of the concentrations in relation to the geographical coordinates were adjusted to a polynomial model. The results obtained showed that the uranium concentrations occur in a distinct way in the different geological formations studied (aluvionar unconsolidated sediments, sandstones and igneous volcanic acid and basic rocks). The uranium variable, when spatialized in relation to the geographical coordinates UTM were adjusted to a second order polynomial model. (author)

  3. Determination of the equivalent doses due to the ingestion of radionuclides from the uranium and thorium series presents in drinking waters of the region of Santa Luzia, Paraiba state, Brazil; Determinacao das doses equivalentes devido a ingestao de radionuclideos das series do uranio e torio presentes em aguas de consumo do municipio de Santa Luzia, estado da Paraiba

    Energy Technology Data Exchange (ETDEWEB)

    Pastura, Valeria F. da S., E-mail: vpastura@cnen.gov.b [Comissao Nacional de Energia Nuclear (DRSN/CNEN), Rio de Janeiro, RJ (Brazil). Diretoria de Radioprotecao e Seguranca Nuclear. Coordenacao de Materias Primas e Minerais; Campos, Thomas F. da C.; Petta, Reinaldo A., E-mail: thomascampos@geologia.ufrn.b, E-mail: petta@geologia.ufrn.b [Universidade Federal do Rio Grande do Norte (LARANA/UFRN), Natal, RN (Brazil). Lab. de Radioatividade Natural

    2011-10-26

    This paper determined the original dose equivalents from radionuclides of uranium and thorium series in a drinking water of well which is supplied to the population of Santa Luzia, Paraiba state, Brazil. The collected waters are near to the mineralized phlegmatic bodies in rose quartz and amazonite feldspar. Radiometric measurements performed on the feldspar vein point out counting ratios surrounding 30000 cps and the analysis of collected samples of minerals presented tenors for the {sup 226}Ra and {sup 219}Pb varying from 0.50 to 2.30 Bq/sw. For determination of concentration of radionuclides U{sub Total}, {sup 226}Ra, {sup 228}Ra and {sup 219}Pb, found in the not desalinated, two methods were used, spectrophotometry with arsenazo and radiochemistry, both realized in the CNEN-LAPOC laboratories. For the calculation of dose equivalent it was taken into consideration the following parameters: the dose coefficients for incorporation by ingestion for public individuals with ages over 17 years (Norma CNEN-NN-3.01, Regulatory Position 3.01/011) and daily ingestion of 4 liters of water, which is over the recommended by the WHO of 2L/day - 1993. The obtained values were compared with the reference value for compromised dose equivalent established by WHO for evaluate the risk potential to the health of population, by ingestion. The radionuclide concentrations in the wells varies from 0.054 to 0.21 Bq/L, resulting dose equivalents of 3.94 x 10{sup -3} mSv/year and 0.17 mSv/year in the studied population

  4. Aspects of radiological safety and protection in the decontamination of the Benefit plant of uranium in Ciudad Aldama and in the storage of its residues in Pena Blanca, Chihuahua, Mexico; Aspectos de seguridad y proteccion radiologica en la descontaminacion de la planta de beneficio de uranio en Ciudad Aldama y en el almacenamiento de sus residuos en Pena Blanca, Chihuahua, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz C, M A [Facultad de Quimica, UNAM (Mexico)

    1998-07-01

    Between 1969 and 1971 the National Commission of Nuclear Energy and the Mining Fostering Commission operated coordinately a production plant of uranium and molybdenum concentrates (Benefit plant) at Ciudad Aldama, Chihuahua, Mexico. During two years of operation some 45 tonnes of uranium concentrate and approximately 35,000 tonnes of uranium wetlands were produced. These last were stored in a dam to 120 m. toward West of the plant. Due to the nearness of the population with respect to what was the Benefit plant and over all to the wetland dam, the objective of this work had two main aspects: On the one hand, to carry out the works of radiological decontamination of the benefit plant of uranium, according to the established normative by the Regulatory organization in matter of radiological safety and protection (CNSNS) for the population and the hard workers. After that the works mentioned were realized it was considered that the estate which comprises what was the Benefit plant did not reach the established criteria by the CNSNS for being considered of unrestricted use such estate and it was not allowed any type of construction in the zone which could be showed the residual contamination which remains there. On the other hand, to determine the site where could be stored the radioactive wastes generated by the radiological decontamination and the wetland mobilization for its definitive storage in benefit of the present population and of the future generations due to the radionuclides which are in a such material. The site more adequate technical and economically to storage the wastes generated by this activity was evaluated. Whereby studies about demography, use of soil and water, meteorology, hydrology and ecology were realized. The site selected being in the Pena Blanca mountains, Chihuahua, place where is located one of the uranium zones and the most important of the country. In this work, specific objectives also were treated such as: knowing the radiological conditions of the benefit plant before and after of the decontamination; realizing indirect measurements which allowing to measure the Ra-226 concentrations and its migration once reached the level of natural estate where was the wetland in the Benefit plant of Ciudad Aldama and in this way to determine the velocity of migration toward freatic mantles in the 25 years which were in the open air without any internal and external protection. (Author)

  5. Analysis of the uranium price predicted to 24 months, implementing neural networks and the Monte Carlo method like predictive tools; Analisis del precio del uranio pronosticado a 24 meses, implementando redes neuronales y el metodo de Monte Carlo como herramientas predictivas

    Energy Technology Data Exchange (ETDEWEB)

    Esquivel E, J.; Ramirez S, J. R.; Palacios H, J. C., E-mail: jaime.esquivel@fi.uaemex.mx [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2011-11-15

    The present work shows predicted prices of the uranium, using a neural network. The importance of predicting financial indexes of an energy resource, in this case, allows establishing budgetary measures, as well as the costs of the resource to medium period. The uranium is part of the main energy generating fuels and as such, its price rebounds in the financial analyses, due to this is appealed to predictive methods to obtain an outline referent to the financial behaviour that will have in a certain time. In this study, two methodologies are used for the prediction of the uranium price: the Monte Carlo method and the neural networks. These methods allow predicting the indexes of monthly costs, for a two years period, starting from the second bimonthly of 2011. For the prediction the uranium costs are used, registered from the year 2005. (Author)

  6. Impact of uranium concentration reduction in side plates of the fuel elements of IEA-R1 reactor on neutronic and thermal hydraulic analyses; Impacto da reducao na concentracao de uranio nas placas laterais dos elementos combustiveis do reator IEA-R1 nas analises neutronica e termo-hidraulica

    Energy Technology Data Exchange (ETDEWEB)

    Rios, Ilka Antonia

    2013-09-01

    This master thesis presents a study to verify the impact of the uranium concentration reduction in the side plates of the reactor IEA-R1 fuel elements on the neutronic and thermal-hydraulic analyses. To develop such study, a previous IPEN-CNEN/SP research was reproduced by simulating the fuel elements burn-up, with side plate uranium density reduced to 50, 60 and 70% of the standard fuel element plates. This research begins with the neutronic analysis using the computer code HAMMER and the first step consists in the calculation of the cross section of all materials presented at the reactor core, with their initial concentration; the second step consists in the calculation of the fast and thermal neutron group fluxes and power densities for fuel elements using the computer code CITATION. HAMMER output data is used as input data. Once the neutronic analysis is finished and the most critical fuel elements with highest power density have been defined, the thermal-hydraulics analysis begins. This analysis uses MCTR-IEA-R1 thermal-hydraulics model, which equations are solved by commercial code EES. Thermalhydraulics analysis input is the power density data calculated by CITATION: it is considered the highest power density on each fuel element, where there is a higher energy release and, consequently, higher temperatures. This data is used on energy balance equations to calculate temperatures on critical fuel element regions. Reactor operation comparison for three different uranium densities on fuel side plates is presented. Uranium density reduction contributes to the cladding surface temperature to remain below the established limit, as reactor operation safety requirement and it does not affect significantly fuel element final burn-up nor reactor reactivity. The reduction of uranium in the side plates of the fuel elements of the IEA-R1 showed to be a viable option to avoid corrosion problems due to high temperatures. (author)

  7. Determination of uranium isotopes ({sup 235}U, {sup 238}U) and trace elements (Cd, Pb, Cu and As) in bottled drinking water by Icp-SFMS; Determinacion de isotopos de uranio ({sup 235}U, {sup 238}U) y elementos traza (Cd, Pb, Cu y As) en agua embotellada para beber por ICP-SFMS

    Energy Technology Data Exchange (ETDEWEB)

    Lara A, N.; Hernandez M, H.; Romero G, E. T.; Kuri de la C, A.; Perez B, M. A., E-mail: nancy.lara@inin.gob.mx [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2016-09-15

    In the present work we propose an optimized method for the quantification of uranium isotopes ({sup 235}U, 2{sup 38}U) and the elements Cd, Pb, Cu and As in bottled water for drinking at trace levels of concentration. Based on the multi-element detection capability, the high sensitivity and resolution that the Mass Spectrometry with Magnetic Sector with Inductively Coupled Plasma Source (Icp-SFMS) technique offers; the high, medium and low resolution analysis conditions for the elements under study were established and optimized using and Element 2/Xr equipment and the 23 multi-elemental Certified Reference Material (CRM). The analysis method was validated using the standard reference material Nist 1643d and CRM mono-elemental s as external standards for the quantification of the analytes. Samples, targets and CRM were acidified with 2% of HNO{sub 3} and analyzed without pretreatment under the established analysis conditions. The results obtained show concentrations of {sup 235}U, {sup 238}U, {sup 111}Cd, {sup 208}Pb, {sup 63}Cu and {sup 75}As in the range of μg L{sup -1}, the linearity obtained from the calibration curves for each element has correlation coefficients < 0.99 in all cases, the accuracy of the method in terms of percent relative standard deviation (RSD %) was less than 5%, the mean recovery rate of Nist 1643d ranged from 96.46% to 101.12%. The optimization of the method guarantees the stability and calibration of the equipment throughout the analysis, as well as the ability to resolve interferences. In conclusion, the method proposed using Icp-SFMS offers the advantages of being fast and simple for the multi-elemental analysis in water at trace levels, with low limits of quantification and detection, with good linearity, accuracy, precision and reproducibility to a degree of reliability of 95%. (Author)

  8. Contributions te the study of methods and factors affecting the spectrophotometric determination of boron traces with carmin uranium compounds; Contribucion al estudio del metodo y factores que afectan a la determinacion espectrofotometrica de trazas de boro con Carmin en compuestos de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez Cellini, R; Gasco Sanchez, L

    1956-07-01

    The study of some factors affecting the spectrophotometric determination of boron traces with carmin is made; the influence of carmin from different origin, the stability of complex carmin-boric acid in relation with the sulphuric acid concentration, the interference produced by ion nitrate, and the ion uraline and light influence are discussed. (Author) 36 refs.

  9. Determination of {sup 2}30Th (Ionium) in uranium ores and wastes from uranium reprocessing. IV. Calculation of ionium separation yield; Determinacion de {sup 2}39Th (Ionio) en minerales y residuos del procesado de Uranio. IV: Determinacion del rendimiento en la separacion del {sup 2}30 Th

    Energy Technology Data Exchange (ETDEWEB)

    Galiano Sedano, J A; Acena Barrenechea, M L

    1974-07-01

    For determining ionium ({sup 2}30Th) in minerals and uranium processing wastes by precipitation with fluorhidric acid, using lanthanum as carrier, and selective extraction with tenoytrifluoroacetone (TTA) followed by radiometric determination of the isolated nuclide, it is necessary the use of a tracer since the chemical yield of the separation ranges between wide limits. In this paper, the use of the beta-emitter {sup 2}34Th as the most convenient tracer is discussed. Equations are derived for correcting for counting errors introduced by other thorium isotopes which are present either in the sample or in the tracer, as well as for calculating the chemical yield of the separation. These equations have been experimentally checked by ionium determinations carried out with different types of samples. (Author) 18 refs.

  10. Uses of complexone III and ion exchange resins in colorimetric determination with o-phenanthroline of Fe traces in uranium compounds; Aplicacion de la complexona III y resinas combadoras a la determinacion colorimetrica con orto-fenantro-lina de trazas de dhierro en compuesto de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez Cellini, R; Ruiz Sanchez, F

    1956-07-01

    The determination of small quantities of iron using o-phenanthroline, assumes the elimination of some cations interference by means of pH control before the formation of a coloured complex. We have eluded that difficulty by the connected action of complexones III and ion exchange. the previous forms quelate with the iron (III) with a stability constant high enough to permit the pass of an iron solution through a cation resin column without being fixed which never occurs with the interferer cations. Mercury is the only element with a similar stability, but it has been eliminated previously. (Author) 16 refs.

  11. Mortality and cancer incident among residents in an area with a geological occurrence of uranium: the municipality of Monte Alegre, PA, Brazil; Avaliacao da incidencia e mortalidade por cancer na populacao residente em regiao com anomalia geologica na ocorrencia de uranio: estudo de caso: Monte Alegre, PA

    Energy Technology Data Exchange (ETDEWEB)

    Melo, Leticia Rodrigues

    2009-04-15

    The municipality of Monte Alegre, located in the Amazonian State of Para, Brazil, presents scattered areas with increased levels of natural radiation due to uranium rocks. The objectives of this dissertation were: to evaluate the mortality trend among Monte Alegre residents, and to compare it with that observed in neighbor municipalities (Alenquer and Prainha) without natural radiation sources; and to determine the impact of cancer distribution either in Monte Alegre or control counties population, taking into account their estimates of cancer incidence and mortality. The dissertation was organized in two papers. The first one aimed to evaluate the mortality trend for all causes of death, cancer, and unknown causes of death occurred between 1981-2005. Analyzed data was provided by the Brazilian National Mortality Information System (SIM), being the general population of the State of Para used as reference. In the second paper, cancer mortality risks at selected sites were ascertained using standardized mortality ratios (SMR) and mortality odds ratios (MOR). Additionally, cancer mortality risk ratios of Monte Alegre and control counties were obtained towards the ratio between SMRs of selected cancer sites in both areas. Three different sources of data were used to retrieve all cancer cases in the studied area, and therefore, to estimate cancer incidence in the studied populations: the diagnosed cancer cases at the regional reference centers for oncological care settled in Santarem, Belem and Manaus; the cancer-related hospitalization authorization records obtained at the Brazilian National Health System (SUS) registries; and primary data of cancer reported by local residents at a population-based health survey conducted by our research team in 2007-2008. A declining trend for all causes of death mortality in Monte Alegre general population, as well as for the unknown causes of death, was observed along the studied time series for both gender. Cancer mortality trend in Monte Alegre and at the control counties remained stable, but the high proportion of unascertained causes of death at the mortality database does not allow a conclusive ascertainment. SMR for all causes of death in Monte Alegre was similar to that observed at the control counties, respectively, SMR=72.9, 95% CI 70,5-75,3 and SMR=75.2 , 95% CI 76,2-77,3. No excess of cancer deaths was observed in Monte Alegre or at the control populations, and cancer mortality by gender also did not reveal statistically significant differences at the different tumor sites. Despite the use of three different approaches to estimate cancer incidence in Monte Alegre and the control counties, similar patterns were observed in the studied areas. To conclude, no evidence supporting an increase of cancer deaths in Monte Alegre was observed. (author)

  12. Levels of potassium, uranium, thorium and rate of radiogenic heat production in the bedrock adjacent to Camamu and Almada sedimentary basins, Bahia, Brazil; Teores de potassio, uranio, torio e taxa de producao de calor radiogenico no embasamento adjacente as bacias sedimentares de Camamu e Almada, Bahia, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Sapucaia, Najara Santos; Barbosa, Johildo Salomao Figueiredo [Instituto de Geociencias, Universidade Federal da Bahia, Salvador, BA (Brazil); Argollo, Roberto Max de, E-mail: nss@cpgg.ufba.br, E-mail: johildo@cpgg.ufba.br, E-mail: robmax@ufba.br [Laboratorio de Fisica Nuclear Aplicada, Instituto de Fisica, Universidade Federal da Bahia, Salvador, BA (Brazil)

    2005-10-15

    The bedrock adjacent to Camamu and Almada sedimentary basins is characterized mainly by rocks of granulite and amphibolite facies, with archaean and paleoproterozoic ages, which belong to orogen Itabuna-Salvador-Curaca. The units in major proportion in this context are the metatonalites associated with basic and metamonzonites belonging to Itabuna belt. In smaller area occur the Teolandia granite and the Moenda granodiorite associated with the Ipiau band amphibolites, the charnockites and charnoenderbites of Jequie bloc, the neoproterozoic sienites and the mafic dikes. The K, U and Th contents of the rocks vary from 0,02 to 6,33% for K, from < 0,2 to 9,10 ppm for U and from < 0,4 to 64,38 ppm for Th. These contents are higher in the charnockites, Moenda granodiorite, Teolandia granite and sienites, intermediate in the metatonalites and metamonzonites and lower in the basic granulites. The heat production rates are higher in the lithologies where K, U and Th are also higher, varying from 0,58 to 5,57 {mu}W m{sup -3}. The coverage areas of such lithologies are, however, small compared with that of the metatonalitic granulites, metamonzonitic granulites and sienites where the rates vary from 0,10 to 1,44 {mu}W m{sup -3}, 0,23 to 5,55 {mu}W m{sup -3} and 0,60 to 2,24 {mu}W m{sup -3}, respectively. In this case, the heat production rates vary from 0,10 to 1,44 {mu}W m{sup -3}. The basic granulites have the smaller rates, from 0,06 to 0,36 {mu}W m-3. The observation of the lithologies in the margins of the two basins suggest that, in the bedrock under the younger sediments, may predominate the metatonalites, followed by the metamonzonites, with some significant participation of sienites in the Almada basin. In those lithologies, the volumetric heat production rates, with one standard deviation range, are 0,41 +- 0,30 {mu}W m{sup -3} for metatonalites, 0,71 +- 0,57 {mu}W m{sup -3} for metamonzonites and 1,20 +- 0,51 {mu}W m{sup -3} for sienites. (author)

  13. Determination of ingestion levels of arsenic, antimony, cadmium, thorium and uranium in children diets by duplicate portion method; Determinacao dos niveis de ingestao dietetica dos elementos arsenio, antimonio, cadmio, torio, tungstenio e uranio em dietas de criancas pelo metodo da porcao em duplicata

    Energy Technology Data Exchange (ETDEWEB)

    Maihara, Vera T.; Vasconcellos, Marina B.A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Supervisao de Radioquimica

    1996-07-01

    A study was made with a group of 19 pre-school children at the central nursery of the University of Sao Paulo with the aim of evaluating the toxic elements contents present in diets of this group. The diet samples were collected by duplicate portion method. A radiochemical was applied to the determination of Cd, Sb, Th, U and W by means of retention of these elements in the chelating resin Chelex 100, in 0,1 M H Ac-NH{sub 4}Ac medium, followed by retention of As in the inorganic exchanger tin dioxide, in HCl 6 M medium. (author)

  14. Effects of the radiation gamma on the activity and selectivity of the Al{sub 2} O{sub 3} in the retention of uranium and fission products; Efectos de la radiacion gamma sobre la actividad y selectividad del Al{sub 2} O{sub 3} en la retencion de uranio y productos de fision

    Energy Technology Data Exchange (ETDEWEB)

    Duran B, J M

    1997-12-31

    The study that here comes constitute a contribution for the treatment of based on waste the properties of retention of the inorganic oxides. The effect induced of the radiation has been determined gamma of the {sup 60} Co in the Al{sub 2} O{sub 3} and their influence in their capacity of retention of uranium and products of fission of watery solutions strongly alkaline. In order to obtain useful information it made the superficial characterizations, structural, crystalline and of retention by means of the techniques of superficial adsorption, spectroscopy infrared, rays-X diffraction, liquid twinkling and {gamma}- spectrometry. The obtained results show that the treatment of the Al{sub 2} O{sub 3} this associated with slight changes in their structural characteristics and superficialities concluding that the molecular water present in the crystalline net of the oxide was not displaced radiolytic for effect, but rather, this spread in the volume of the oxide, blocking the change in the contribution to crystalline of the oxide. (Author).

  15. Study of an X-ray fluorescence thin film method for the determination of uranium in low activity solutions; Estudio de un metodo de fluorescencia de rayos X en capa delgada para la determinacion del uranio en soluciones de baja actividad

    Energy Technology Data Exchange (ETDEWEB)

    Diaz-Guerra, J P

    1980-07-01

    The application of the X-ray fluorescence thin film technique to the uranium determination in nitric solutions for a concentration range from 1 g/l to 100 g/l and activity levels under 5 mCi/ml is studied. The most suited excitation and measurement conditions are also studied and the uranium matrix effect correction, which is performed through the double dilution, {alpha}{sub U}U interaction coefficient calculation and internal standard methods, is discussed. The specimen preparation is satisfactorily accomplished by using P.V.C. filters fixed on aluminium supports. (Author) 18 refs.

  16. Metallogenetic characterization of granitoid rocks through geochemical prospection: the Lagoa Real example related to uranium mineralization in Bahia state, Brazil; Caracterizacao metalogenetica de corpos gratinoides atraves de prospeccao geoquimica: o exemplo da suite intrusiva Lagoa Real relacionada a mineralizacoes de uranio no Estado da Bahia

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, J.E., E-mail: cprmsa@bahianet.com.br [Servico Geologico do Brasil (GEREMI/SUREG/SA/CPRM), Salvador, BA (Brazil)

    2011-07-01

    Within a broad metallogenetic evaluation program carried out by CPRM - Geological Survey of Brazil in covenant with the CBPM - Companhia Baiana de Pesquisa Mineral in the central part of the Sao Francisco Craton, the Lagoa Real granitoid rocks was one of the selected targets. The work included geochemical exploration supplemented by follow-in survey and integrated 1:200.000 scale geochemical cartography. The Lagoa Real granitoid was recognized with composition ranging from monzogranitic to alcaligranitic type. The geochemical surveying led to the definition of the metallogenetic specialization of the granitoid rock, with characteristic geochemical and mineralogic associations. These associations are related to uranium mineralization. The genetic model using stream sediment and pan concentrate data, show similarity with the metallogenetic model of zonal partitioning proposed by Routhier (1963), for plutonogenic lode deposits with potential for Sn, W, Nb, Be, REE, Au, and U. In this work emphasis is given to the importance of the integrated use of different prospective methods toward the evaluation of granitoid systems, particularly the combination of geochemical surveying methods with results for a better understanding of the geologic and metallogenetic settings. (author)

  17. El impacto del Flipped Classroom como proceso para la revisión previa de los contenidos y materiales de los cursos o talleres de capacitación del personal administrativo del Instituto Tecnológico y de Estudios Superiores de Monterrey, Campus Guadalajara

    OpenAIRE

    Robledo Martínez, Rosario Sarahí

    2015-01-01

    La presente investigación se llevó a cabo en la ciudad de Guadalajara, Jalisco, México, en las instalaciones del Tecnológico de Monterrey. El estudio se dirigió en su totalidad a los empleados administrativos que laboran en las distintas áreas de la institución, como lo son los profesionistas de apoyo, los auxiliares, las secretarias, los jefes de área, entre otros, con el firme propósito de involucrar la metodología basada...

  18. Multinodular goiter treatment with radioiodine aided by recombinant human TSH in different doses: a randomized, double-blind, placebo-controlled study;Administracao previa do TSH humano recombinante, em diferentes doses, no tratamento do bocio multinodular com iodo radioativo: um estudo randomizado, duplo cego, controlado com placebo

    Energy Technology Data Exchange (ETDEWEB)

    Albino, Claudio Cordeiro

    2009-07-01

    Background: There is not an optimal treatment for multinodular goiter (MNG). Surgery is the main therapeutic option because it decreases thyroid volume, reduces compression symptoms and provide histological diagnosis. Radioiodine ({sup 131}I) is an efficient therapeutic option for the treatment of MNG mainly when surgery is not indicated or when the patient refused it. However, high activities of {sup 131}I are frequently required for clinically significant results. This procedure increases the body radiation exposure and the hospitalization costs. Recombinant human TSH (rh TSH) allows a reduction in the administered activity of {sup 131}I with effective thyroid volume (TV) reduction. However, this combination therapeutic can increase collateral effects. Objective: To evaluate the efficacy and safety of low and intermediate doses of rh TSH compared to placebo, associated with a fixed activity of {sup 131}I in MNG treatment. Patients and Methods: Thirty patients with MNG received 0.1 mg of rh TSH (group I, n=10), 0.01 mg of rh TSH (group II, n=10), or placebo (control group, n=10). After 24 hours, 30 mCi of {sup 131}I was given to all patients. Radioactive iodine uptake (RAIU) was determined before and 24 hours after rh TSH. Before and 2, 7, 180 and 360 days after the TV was measured by magnetic resonance image (MRI). The smallest cross-sectional area of tracheal lumen (Scat) was also measured with MRI before, 2 and 7 days after treatment. Antithyroid antibodies, TSH, T3 and free T4 were assessed regularly. Results: After 6 months, the decrease in TV was more significant in groups I (30.3 +- 16.5%) and II (22.6 +- 14.5%), than in control group (5.0 +- 14.6%; p=0.01). After 12 months, TV decreased more in group I (39.2 +- 16.9%) and group II (38.8 +- 24.4%) than in group III (23.4 +- 23.59%) but it was not statistically significant (p=0.205). During the first 30 days,total T3 and free T4 increased, without reaching thyrotoxic levels and TSH decreased. After 12 months, 8 patients developed hypothyroidism (3 in group I, 3 in group II and 2 in group III). Anti-thyroglobulin antibodies (anti-TG) titers increased after 6 months and returned to basal levels after 12 months similarly in all groups. There was more patients with anti-thyroperoxidase antibodies (anti-TPO) titers increased after 12 months on group I. There was not TV increase after {sup 131}I on the first week ,with or without rh TSH. Conclusion: The previous stimulus with rh TSH using a fixed {sup 131}I activity lead to a greater and more significant goiter reduction after six months of treatment than {sup 131}I alone. After twelve months this tendency was maintained, but without statistic relevance. (author)

  19. Quality of previous diabetes care among patients receiving services at ophthalmology hospitals in Mexico Calidad de la atención previa de los pacientes diabéticos atendidos en hospitales de oftalmología en México

    Directory of Open Access Journals (Sweden)

    Joel Rodríguez-Saldana

    2010-12-01

    Full Text Available OBJECTIVE: To survey a large sample of type 2 diabetes mellitus (T2DM patients in Mexico City to determine if patient experience, access to basic services, treatment, and outcomes differed between those with social security coverage and those without. METHODS: From 2001-2007 a total of 1 000 individuals with T2DM were surveyed in outpatient clinics of the three largest public ophthalmology hospitals in Mexico City. Patients reported information about their health status and receipt of basic diabetes services, such as laboratory glycemic monitoring and diabetes education. Rates were compared between those with (n = 461 and without (n = 539 social security. RESULTS: Almost half of the patients (46% in these public facilities were social security patients that were unable to access other services and had to pay out-of-pocket for care. Half of respondents were originally identified as potentially diabetic based on symptom complaints (51%, including 11% with visual impairment. Most patients (87.9% reported that their glycemic level was being monitored exclusively via fasting blood glucose testing or random capillary blood glucose tests; only 5.3% reported ever having a glycated hemoglobin test. While nearly all respondents reported an individual physician encounter ever, only 39% reported ever receiving nutrition counseling and only 21% reported attending one or more sessions of diabetes education in their lifetime. Processes of care and outcomes were no different in patients with and those without social security coverage. CONCLUSIONS: In Mexico, the quality of diabetes care is poor. Despite receiving social security, many patients still have to pay out-of-pocket to access needed care. Without policy changes that address these barriers to comprehensive diabetes management, scientific achievements in diagnosis and pharmacotherapy will have limited impactOBJETIVO: Determinar si hay diferencias en cuanto a las experiencias de atención de la diabetes, el acceso a los servicios básicos, el tratamiento y la evolución clínica entre las personas que disponen o no de seguro social de salud mediante la encuesta de una muestra amplia de pacientes que padecen diabetes mellitus tipo 2 en la Ciudad de México. MÉTODOS: Se encuestó a 1 000 pacientes con diabetes tipo 2 en la consulta externa de los tres hospitales públicos de oftalmología más importantes de la Ciudad de México. Los pacientes proporcionaron información acerca de su estado de salud y su experiencia respecto de la atención básica de diabetes; por ejemplo, el control de la glucemia mediante análisis de laboratorio y la información que recibieron acerca de la enfermedad. Se compararon los datos estadísticos entre quienes disponían de un seguro social de salud (n = 461 y quienes carecían de este tipo de seguro (n = 539. RESULTADOS: Casi la mitad de los pacientes (46% que se atienden en estos hospitales públicos disponen de seguro social de salud, pero no pudieron acceder a otros servicios y debieron pagar de su bolsillo para recibir atención. La mitad de los entrevistados (51% eran pacientes que habían sido considerados presuntos diabéticos a partir de los síntomas que habían referido, de los cuales 11% presentaron discapacidad visual. La mayoría de los pacientes (87,9% refirieron que solo se controlaban mediante análisis glucemia en ayunas o análisis aleatorios (sin ayunar de una muestra de sangre capilar; solo 5,3% refirieron que alguna vez se habían efectuado el análisis de glucohemoglobina (HbA1c. Si bien prácticamente la totalidad de los encuestados refirieron haber tenido alguna consulta médica, solo 39% informaron haber recibido orientación nutricional en alguna ocasión y solo 21% refirieron haber asistido a una o más sesiones informativas sobre la diabetes. No se registraron diferencias en la atención ni la evolución clínica entre los pacientes que disponen de un seguro social de salud y aquellos que carecen de este tipo de seguro. CONCLUSIONES: En México, es deficiente la calidad de la atención en materia de diabetes. A pesar de contar con un seguro social de salud, muchos pacientes deben pagar de su bolsillo para acceder a la atención que necesitan. De no modificarse las políticas con el fin de abordar los obstáculos que encuentran los pacientes para acceder al tratamiento integral de la diabetes, serán limitadas las repercusiones de los avances científicos que tengan lugar en materia de diagnóstico y farmacoterapia

  20. Información financiera al servicio de la imagen. Estados contables del nuevo banco español de San Fernando y su sucesor el Banco de España, en la etapa previa al privilegio de emisión (1847-1873

    Directory of Open Access Journals (Sweden)

    Rafael Moreno Fernández

    2008-12-01

    cualitativo y diferente del puramente contable o legalista, que es el que se practicaba en la época, y también con posterioridad. En el mundo actual con la normalización contable de los estados financieros, no puede hacerse, en general, este tipo de análisis directo, si bien la imagen exterior que se transmite en la Memorias de cualquier empresa no suele dejarse al azar, puesto que es componente de su reputación.

  1. Influence of the Previous History of the Raw Material on Sintering of UO{sub 2}; Influence des antecedents de la matiere premiere sur le frittage de UO{sub 2}; Vliyanie obrabotki iskhodnogo veshchestva na spekanie UO{sub 2}; Influencia de la historia previa de la materia prima sobre la sinterizacion del UO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Aparicio, E.; Alonso, J. A.; Pedregal, J. D. [Junta de Energia Nuclear Madrid (Spain)

    1963-11-15

    An account is given of the experimental principles underlying the production process of a UO{sub 2} pellet plant. In this process, advance determination of the particle-size distribution characteristics of the raw material is secured not by means of controlled precipitation but by the crushing and grading of powders. The uranium oxides tested in this work are conventional materials, representing types of fabrication which differ by origin and method used. A study of the pellets obtained shows the potentialities and limitations of each type of oxide in the process adopted. A description is given of the characteristics of the powders as regards specific area, particlesize distribution, differential and thermogravimetric thermal analyses, and stoichiometry, and of the density, contraction, structure and stoichiometry of the pellets. (author) [French] Les auteurs decrivent les experiences qui ont servi de base aux operations d'une installation de fabrication de pastilles d'UO{sub 2}. Selon la methode employee, pour fixer a l'avance les caracteristiques granulometriques de la matiere premiere, on ne procede pas a une precipitation controlee, mais a un broyage et a un criblage des poudres. Les uranes qui ont fait l'objet de ce travail sont des produits classiques provenant de fabrications qui different par l'origine et le procede de transformation. De l'etude des pastilles obtenues, on deduit les possibilites et les limites de chaque type d'urane par rapport au procede adopte. On controle les caracteristiques suivantes: pour les poudres, la surface specifique, la granulometrie; les proprietes thermiques differentielles et thermogravimetrique et la stoechiometrie; pour les pastilles, la densite, la contraction, la structure et la stoechiometrie des pastilles. (author) [Spanish] Se exponen los fundamentos experimentales sobre los que se basa el proceso de una planta de fabricacion de pastillas de UO{sub 2} . En este proceso no se emplea la precipitacion controlada como medio de prefijar las caracteristicas granulometricas de la materia prima, sino la molienda y clasificacion de los polvos. Las uranias ensayadas en este trabajo son materiales convencionales representantes de tipos diferentes de fabricacion por el origen y metodo operatorio. Del estudio de las pastillas obtenidas se deducen las posibilidades y limitaciones de cada tipo de urania en el proceso adoptado. Se controlan las caracteristicas de superficie especifica, granulometria, analisis termico diferencial y termogravimetricoy estequiometria de los polvos, asi como la densidad, contraccion, estructura y estequiometria de las pastillas. (author) [Russian] Izlagayutsya ehksperimental'nye dannye, na kotorykh osnovan primenyaemyj odnim zavodom metod izgotovleniya tabletok UO{sub 2}. Soglasno ehtomu metodu granulometricheskaya kharakteristika iskhodnogo veshchestva opredelyaetsya zaranee ne putem upravlyaemogo osazhdeniya, a razmel'cheniem i sortirovkoj poroshka. V dannoj rabote ispol'zovalis' obraztsy obychnoj okisi urana, otlichayushchiesya po sposobu izgotovleniya i po proiskhozhdeniyu. Issledovanie privelo k nekotorym vyvodam otnositel'no vozmozhnostej i ogranichenij metoda v zavisimosti ot tipa ispol'zuemoj okisi urana. Privodyatsya rezul'taty izmereniya udel'noj poverkhnosti, granulometrii, termicheskikh differentsial'nogo i termogravimetricheskogo analizov i stekhiometrii poroshkov, a takzhe po plotnosti usadki, strukture i stekhiometrii tabletok. (author)

  2. La Investigación Básica. La Investigación en Ciencias Fisiológicas: Bioquímica, Biología Molecular y Fisiología. Cuestiones Previas Basic Research. Research in Physiological Sciences: Biochemistry, Biophysics, Molecular Biology and Physiology. Some prior considerations

    Directory of Open Access Journals (Sweden)

    Constancio González Martínez

    2004-03-01

    Full Text Available La conferencia impartida los últimos días de enero de 2004 en las Dependencias del Instituto Carlos III (Madrid ante un grupo de colegas latinoamericanos, y que transcribo en el escrito que sigue, ha tenido como objetivo fundamental tratar de conjugar algunas ideas sobre investigación con la realidad socioeconómica de los países de Latinoamérica. En la primera parte de la conferencia he dado un concepto de Investigación y he enfatizado el valor que la consideración de la teleología de los fenómenos biológicos tiene en el avance de las propias ciencias biológicas. A continuación, he pasado revista de forma muy rápida a las Normas del Bien Hacer en le Laboratorio o Good Laboratory Practices, y he presentado unos pocos datos objetivos sobre la realidad económica de los países latinoamericanos. En una segunda parte, he tratado de promover en nuestros colegas latinoamericanos una actitud reivindicativa que les ayude a pedir a sus gobernantes y a defender frente a sus conciudadanos, la necesidad de implementar una política científica clara como una prioridad nacional. Tal reivindicación estaría apoyada en el reconocimiento de que la investigación es una herramienta para aprovechar la capacidad intelectual de los ciudadanos de cada país, de que la investigación es un medio para aprovechar recursos de organismos internacionales, de que la investigación es una fuente de cultura que contribuye a la creación de una identidad nacional y, finalmente, de que la investigación es una actividad generadora de riqueza y bienestar. Concluyo la conferencia señalando que la investigación básica, y por tanto la investigación en Ciencias Fisiológicas, está ensamblada tan estrechamente con la investigación aplicada que constituyen una realidad única.This article is a transcription of a conference addressed to a group of colleagues from Latin America at the end of January 2004, in the Instituto Carlos III (Madrid. Its main purpose was to conjugate some general ideas on scientific research with known facts on the socioeconomic reality of Latin American countries. In the initial part of the talk I put forward a definition of research, emphasizing the great value of considering the teleology of biological phenomena for the advance of biological sciences. A succinct consideration of the importance of Good Laboratory Practices, especially if there is not a tradition of research, drove my talk to the presentation of some basic data on the socioeconomic situation of the Latin American countries. In the second half of the conference my efforts were directed to incite our Latin American colleagues to demand from their politicians, and to justify in front of their fellow citizens, the necessity of implementing a program on scientific research as a national priority. Such demand should be justified on the basis of the recognition that research represents a way to correctly use the intellectual capital of the citizens of every country and a mean to profit from free international resources, that research is a source of culture, contributing to the national identity of any given country, and finally, on the fact that research is an activity that generates wealth. I concluded my talk pointing out that basic research, and therefore research in physiological sciences, is assembled so tight with basic research that they conform a unique reality.

  3. Application of the new requirements of safety of the IAEA for the previous management to the final disposal of radioactive waste in the region: a personal vision; Aplicacion de los nuevos requisitos de seguridad del OIEA para la gestion previa a la disposicion final de desechos radiactivos en la region: una vision personal

    Energy Technology Data Exchange (ETDEWEB)

    Sed, Luis Andres Jova, E-mail: jovaluis@gmail.com [Centro Nacional de Seguridad Nuclear (CNSN), La Habana (Cuba)

    2013-07-01

    The work includes the requirements for the responsibilities associated with the management prior to the final disposal of radioactive waste and as they are referred to in the Region. Also discusses the requirements for the main stages of the management prior to the final disposal of radioactive waste. A very important section of the new requirements is that establish requirements for safe operation of facilities management prior to the final disposal of radioactive wastes and the implementation of activities under conditions of safety and development. The work is emphatic on the importance of safety justification since the beginning of the development of a facility as a basis for the decision-making and approval process. Emphasis is also on the gradual approach which should provide for the collection, analysis and interpretation of the relevant technical data, plans for the design and operation, and the formulation of the justification of the security. This paper gives a personal view of the situation in the Region.

  4. humano en Costa Rica

    Directory of Open Access Journals (Sweden)

    Luis Guillermo Loría

    2007-01-01

    Full Text Available Usando la técnica de espectrometría gamma y protocolos estandarizados, a nivel latinoamericano, se midió la actividad específica en Bq kg-1 de productos alimentarios y agua, ambos productos fueron adquiridos directamente en los supermercados. Los descendientes de uranio y torio, así como isótopos antropogénicos, no fueron encontrados. K 40 es el único isótopo natural presente en los productos.

  5. Surface decontamination in the old storage shed number 99 of the General Plan of IPEN/CNEN-SP, containing production equipment of natural uranium hexafluoride (UF{sub 6}), aiming at its decommissioning; Descontaminacao de superficies no antigo galpao de estocagem numero 99 da planta geral do IPEN/CNEN-SP, contendo equipamentos da producao de hexafluoreto de uranio natural, (UF{sub 6}), visando seu descomissionamento

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Claudio C. de; Cambises, Paulo B.S.; Paiva, Julio E. de; Paiva, Julio E. de; Silva, Teresina M.; Rodrigues, Demerval L., E-mail: calmeida@ipen.br, E-mail: cambises@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

    2013-11-01

    This paper presents the steps adopted in the operation planned for the decontamination of surfaces in the old storage shed number 99 the general layout of the Energy Research and Nuclear IPEN-CNEN/SP, Brazil, and contained various types of equipment originating from production hexafluoride natural uranium (UF6). This operation involved the planning, training of operators of the facility, analysis of workplaces and radiometric surveys for monitoring of external radiation and surface contamination. The training involved the procedures for decontamination of surfaces, segregation of materials and practical procedures for individual monitoring of contamination outside of the body. Were also established rules for the transport of radioactive materials in the internal and external facility and release of material and sites already decontaminated.

  6. Communication Received from the United Kingdom of Great Britain and Northern Ireland Concerning its Policies Regarding the Management of Plutonium. Statements on the Management of Plutonium and of High Enriched Uranium; Comunicacion recibida del Reino Unido de Gran Bretana e Irlanda del Norte en relacion con sus politicas referentes a la gestion del plutonio. Declaraciones sobre la gestion del plutonio y del uranio muy enriquecido

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-19

    The Secretariat has received a note verbale dated 6 June 2011 from the Permanent Mission of the United Kingdom of Great Britain and Northern Ireland to the IAEA in the enclosures of which the Government, in keeping with its commitment under the Guidelines for the Management of Plutonium (contained in INFCIRC/549 of 16 March 1998 and hereinafter referred to as the 'Guidelines') and in accordance with Annexes B and C of the Guidelines, has made available annual figures for its holdings of civil unirradiated plutonium and the estimated amounts of plutonium contained in spent civil reactor fuel as of 31 December 2010 [Spanish] La Secretaria ha recibido una nota verbal, de fecha 6 de junio de 2011, de la Mision Permanente del Reino Unido de Gran Bretana e Irlanda del Norte ante el OIEA, en cuyos anexos el Gobierno, en cumplimiento de su compromiso contraido en virtud de las Directrices para la gestion del plutonio (transcritas en el documento INFCIRC/549 de 22 de junio de 1998 y denominadas en adelante las 'directrices') y de conformidad con los anexos B y C de las directrices, presenta las cifras anuales de sus existencias de plutonio no irradiado de uso civil y las cantidades estimadas de plutonio contenido en el combustible gastado de reactores de uso civil, a 31 de diciembre de 2010.

  7. Communication Received from the United Kingdom of Great Britain and Northern Ireland Concerning its Policies Regarding the Management of Plutonium. Statements on the Management of Plutonium and of High Enriched Uranium; Comunicacion recibida del Reino Unido de Gran Bretana e Irlanda del Norte en relacion con sus politicas referentes a la gestion del plutonio. Declaraciones sobre la gestion del plutonio y del uranio muy enriquecido

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-09-13

    The Secretariat has received a note verbale dated 28 July 2010 from the Permanent Mission of the United Kingdom of Great Britain and Northern Ireland to the IAEA in the enclosures of which the Government, in keeping with its commitment under the Guidelines for the Management of Plutonium (contained in INFCIRC/549 of 16 March 1998 and hereinafter referred to as the 'Guidelines'), and in accordance with Annexes B and C of the Guidelines, has made available annual figures for its holdings of civil unirradiated plutonium and the estimated amounts of plutonium contained in spent civil reactor fuel as of 31 December 2009 [Spanish] La Secretaria ha recibido una nota verbal, de fecha 28 de julio de 2010, de la Mision Permanente del Reino Unido de Gran Bretana e Irlanda del Norte ante el OIEA, en cuyos anexos el Gobierno, en cumplimiento de su compromiso contraido en virtud de las Directrices para la gestion del plutonio (transcritas en el documento INFCIRC/549 de 16 de marzo de 1998 y denominadas en adelante las 'directrices') y de conformidad con los anexos B y C de las directrices, presenta las cifras anuales de sus existencias de plutonio no irradiado de uso civil y las cantidades estimadas de plutonio contenido en el combustible gastado de reactores de uso civil, a 31 de diciembre de 2009.

  8. Communication Received from the United Kingdom of Great Britain and Northern Ireland Concerning its Policies Regarding the Management of Plutonium. Statements on the Management of Plutonium and of High Enriched Uranium; Comunicacion recibida del Reino Unido de Gran Bretana e Irlanda del Norte en relacion con sus politicas referentes a la gestion del plutonio. Declaraciones sobre la gestion del plutonio y del uranio muy enriquecido

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-10-30

    The Secretariat has received a note verbale dated 26 June 2009 from the Permanent Mission of the United Kingdom of Great Britain and Northern Ireland to the IAEA in the enclosures of which the Government, in keeping with its commitment under the Guidelines for the Management of Plutonium (contained in INFCIRC/549 of 16 March 1998 and hereinafter referred to as the 'Guidelines') and in accordance with Annexes B and C of the Guidelines, has made available annual figures for its holdings of civil unirradiated plutonium and the estimated amounts of plutonium contained in spent civil reactor fuel as of 31 December 2008 [Spanish] La Secretaria ha recibido una nota verbal, de fecha 26 de junio de 2009, de la Mision Permanente del Reino Unido de Gran Bretana e Irlanda del Norte ante el OIEA, en cuyos anexos el Gobierno, en cumplimiento de su compromiso contraido en virtud de las Directrices para la gestion del plutonio (transcritas en el documento INFCIRC/549 de 22 de junio de 1998 y denominadas en adelante las 'directrices') y de conformidad con los anexos B y C de las directrices, presenta las cifras anuales de sus existencias de plutonio no irradiado de uso civil y las cantidades estimadas de plutonio contenido en el combustible gastado de reactores de uso civil, a 31 de diciembre de 2008.

  9. Communication Received from the United Kingdom of Great Britain and Northern Ireland Concerning Its Policies Regarding the Management of Plutonium. Statements on the Management of Plutonium and of High Enriched Uranium; Comunicacion recibida del Reino Unido de Gran Bretana e Irlanda del Norte en relacion con sus politicas referentes a la gestion del plutonio. Declaraciones sobre la gestion del plutonio y del uranio muy enriquecido

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-09-25

    The Secretariat has received a Note Verbale dated 23 August 2007 from the Permanent Mission of the United Kingdom of Great Britain and Northern Ireland to the United Nations and the International Organizations in Vienna in the enclosures of which the Government, in keeping with its commitment under the Guidelines for the Management of Plutonium (contained in INFCIRC/549 of 16 March 1998 and hereinafter referred to as the 'Guidelines') and in accordance with Annexes B and C of the Guidelines, has made available annual figures for its holdings of civil unirradiated plutonium and the estimated amounts of plutonium contained in spent civil reactor fuel as of 31 December 2006 [Spanish] La Secretaria ha recibido una nota verbal, de fecha 23 de agosto de 2007, de la Mision Permanente del Reino Unido de Gran Bretana e Irlanda del Norte ante las Naciones Unidas y las Organizaciones Internacionales con sede en Viena, en cuyos anexos el Gobierno, en cumplimiento de su compromiso contraido en virtud de las Directrices para la gestion del plutonio (transcritas en el documento INFCIRC/549 de 16 de marzo de 1998 y denominadas en adelante las 'Directrices') y de conformidad con los anexos B y C de las Directrices, presenta las cifras anuales de sus existencias de plutonio no irradiado de uso civil y las cantidades estimadas de plutonio contenido en el combustible gastado de reactores de uso civil, a 31 de diciembre de 2006.

  10. Report about drilling works made in 13 Anomaly de Taylor and in the N- NE of its, around Fraile Muerto (Cerro Largo district): Uranium project[Study of Uranium prospection in Uruguay]; Informe sobre los trabajos de perforacion efectuados en la Anomalia 13 de Taylor y al N-NE de la misma , en los alrededores de Fraile Muerto (Departamento de Cerro Largo). Proyecto Uranio

    Energy Technology Data Exchange (ETDEWEB)

    Massa, J; Pirelli, H

    1983-07-01

    The perforations were carried out to investigate in depth denominated anomaly 13 detected during the Taylor Mission (1975) and extended the punch area of study during you are suitable DINAMIGE-BRGM (Project the present report details the activities realised in the environs Fraile Muerto (Cerro Largo district) by the command team of perforations of the uranium project. Previously and contemporarily to the executed works, prospection became geophysical ground geochemistry geology and, works. (Uranium)

  11. Study of new complexes of uranium and comba radical. II-Complexes formed in the presence of OH{sup -}, CO{sub 3}H{sup -}, CH{sub 3}-COO{sup -}, and B{sub 4}={sub 7}; Estudio de nuevos complejos entre uranio y el radical CADMBA. II. Complejos formados en presencia de OH{sup -}, CO{sub 3}H, CH{sub 3}-COO{sup -} y B{sub 4}O{sub 7}

    Energy Technology Data Exchange (ETDEWEB)

    Vera Palomino, V; Galiano Sedano, J A; Parellada Bellod, R; Bellido Gonzalez, A

    1975-07-01

    Several complexes extracted with CDMBAC organic solutions from uranium aqueous solutions, in presence of sodium and ammonium hydroxides, are studied. These complexes fit to the general formula: U0{sub 2}(OH){sub n}(CDMBA){sub n}-2 . The uranium extraction in presence of an excess of sodium bicarbonate is also studied. From aqueous solutions of uranyl acetate we have isolated the complex U0{sub 2}(CH{sub 3}-C00){sub n} (CDMBA){sub n}-2. In presence of boric acid and sodium tetraborate an U-CDMBA compound containing boron in its molecule has being obtained by precipitation and liquid-liquid extraction. (Author) 5 refs.

  12. Medline Plus

    Full Text Available ... head is too large to fit through the birth canal If labor is prolonged and the mother's ... placenta previa, where the placenta is blocking the birth canal If there are signs of fetal distress ...

  13. Placenta: How It Works, What's Normal

    Science.gov (United States)

    ... placental problems include placental abruption, placenta previa and placenta accreta. These conditions can cause potentially heavy vaginal bleeding. ... health care provider will recommend a C-section. Placenta accreta. This condition occurs when the blood vessels and ...

  14. Role of MRI versus ultras

    Directory of Open Access Journals (Sweden)

    Lamiaa Bassam Hashem

    2016-06-01

    Conclusion: Magnetic resonance imaging is complementary to Ultrasound and it is important for the accurate diagnosis of placental abnormalities especially placenta previa and the seriously co-existing placenta accreta.

  15. Aplicación de un sistema de monitorización de la concentración de gas radón en el agua de una instalación termal

    OpenAIRE

    Rábago Gómez, Daniel

    2013-01-01

    Se han analizado los niveles de radón (222Rn) en el agua y en el aire del balneario Las Caldas de Besaya de forma continua a lo largo de un año aproximadamente. El radón es un gas noble de origen natural procedente de la desintegración del radio (226Ra) ambos constituyentes de la serie radiactiva del uranio 238. Dicho gas ha sido reconocido como agente carcinógeno de pulmón por la Organización Mundial de la Salud (WHO) y la Agencia Internacional de Investigación del Cáncer (...

  16. Royal Decree 1899/1984 of 1 August amending Royal Decree 2967/1979 of 7 December on the organisation of activities in the nuclear fuel cycle

    International Nuclear Information System (INIS)

    1984-01-01

    Under the Decree of 1979 the ''Empresa Nacional del Uranio SA'' (National Uranium Enterprise - ENUSA) was responsible for spent management while the Junta de Energia Nuclear (JEN) was responsible for the final storage of radioactive waste. However, these provisions do not cover waste resulting from activities outside the fuel cycle or the dismantling of nuclear and radioactive installations, nor do they provide a global solution to the different problems involved in organising the overall management of radioactive waste. Therefore, this Decree authorises the National Enterprise for Radioactive Waste (ENRESA) to perform the tasks prescribed in this field by the 1964 Nuclear Energy Act and the 1979 Decree. (NEA) [fr

  17. Process system of radiometric and magnetometric aerial information

    International Nuclear Information System (INIS)

    Bazua Rueda, L.F.

    1985-01-01

    The author has been working first in the National Institute of Nuclear Energy (Mexico) and then in URAMEX (Uranio Mexicano) since 1975 to 1983, integrated to radiometric and magnetometric aerial prospecting projects in computerized processing of information aspects. During this period the author participated in the work out of computing systems, information processing and mathematical procedures definition for the geophysical reduction of the calibration equipment data. With cumulated experience, in this thesis are presented aspects concerning to management and operation of computerized processing of information systems. Operation handbooks of the majority of modules are presented. Program lists are not included. (Author)

  18. Estudio preliminar de la mineralización uranífera en la cordillera oriental, San Ramón, Oxapampa

    OpenAIRE

    Valencia, Jacinto

    2014-01-01

    Rocas intrusivas del magmatismo permo-triásico de la cordillera oriental, constituidas por granitos de San Ramón y Oxapampa, presentan buena favorabilidad como rocas fértiles en uranio, un granito de facie roja denominado monzo-granito; esta condición es el resultado de la ejecución del proyecto de cooperación del OIEA PER 2/16, a cargo de IPEN, “Mejora del conocimiento del potencial uranífero del Perú”. Los trabajos de campo han consistido en la revisión geológico-radiométrica y toma de mues...

  19. 18536 - Royal Decree 813/1988 of 15 July amending Royal Decree 1611/1985 of 17 July on the organization of nuclear fuel cycle activities

    International Nuclear Information System (INIS)

    1988-07-01

    The 1985 Decree had amended a 1979 Decree on the organisation of activities in the nuclear fuel cycle by providing in particular that the National Uranium Undertaking (Empresa Nacional del Uranio - ENUSA) should progressively reduce its stockpile of nuclear fuels. This Decree amends the 1985 Decree providing inter alia, that after the first nuclear fuel loading, pressurized water and boiling water reactors (PWR and BWR) in nuclear power plants should have a stockpile of fuel elements available at all times. The number of elements will be fixed for each plant by the Ministry of Industry and Energy [fr

  20. Análisis geoestadístico en el estudio de la explotación de los recursos minerales

    OpenAIRE

    Chica Olmo, Mario

    2013-01-01

    La Tesis Doctoral del Sr. Chica Olmo constituye una aproximación geoestadística al estudio de explotación de los recursos minerales de modo que en la memoria se recogen las principales conclusiones metodológicas teóricas y practicas alcanzadas a través de diferentes estudios y proyectos llevados a cabo en el dominio minero referentes a depósitos de naturaleza variada como carbón uranio plomo plata... En gran medida los anteriores estudios han sido realizados en el centro de geoestadística de ...

  1. An??lisis geoestad??stico en el estudio de la explotaci??n de los recursos minerales

    OpenAIRE

    Chica Olmo, Mario

    1987-01-01

    La Tesis Doctoral del Sr. Chica Olmo constituye una aproximaci??n geoestad??stica al estudio de explotaci??n de los recursos minerales de modo que en la memoria se recogen las principales conclusiones metodol??gicas te??ricas y practicas alcanzadas a trav??s de diferentes estudios y proyectos llevados a cabo en el dominio minero referentes a dep??sitos de naturaleza variada como carb??n uranio plomo plata... En gran medida los anteriores estudios han sido realizados en el centro de geoestad??...

  2. El desarrollo nuclear de Argentina y el régimen de no proliferación

    OpenAIRE

    Colombo, Sandra; Guglielminotti, Cristian; Vera, María Nevia

    2017-01-01

    Resumen: El desarrollo y la transferencia de tecnología nuclear han sido puestos bajo estrictos controles debido a su posible derivación hacia el uso bélico, lo que ha llevado a crear un régimen internacional de no proliferación. Una de las últimas propuestas ha sido la fundación de bancos multilaterales de uranio levemente enriquecido (ule). Este artículo plantea que el objetivo de no proliferación puede contribuir a acentuar la asimetría en la distribución del poder económico-político mundi...

  3. Prevention of criticality accidents. Fuel elements storage; Prevencion de accidentes de criticidad. Almacenamiento de elementos combustibles

    Energy Technology Data Exchange (ETDEWEB)

    Canavese, S I; Capadona, N M

    1991-12-31

    Before the need to store fuel elements of the plate type MTR (Materials Testing Reactors), produced with enriched uranium at 20% in U235 for research reactors, it requires the design of a deposit for this purpose, which will give intrinsic security at a great extent and no complaints regarding its construction, is required. (Author). [Espanol] Partiendo de la necesidad de almacenar elementos combustibles tipo placa MTR (Materials Testing Reactors), producidos con uranio enriquecido al 20% en U235 para reactores de investigacion, se requiere el diseno de un deposito para tal fin que brinde esencialmente un alto grado de seguridad intrinseca y que no ofrezca complicaciones en cuanto a su construccion. (Autor).

  4. Risk factors for blood transfusion in patients undergoing high-order Cesarean delivery.

    Science.gov (United States)

    Spiegelman, Jessica; Mourad, Mirella; Melka, Stephanie; Gupta, Simi; Lam-Rachlin, Jennifer; Rebarber, Andrei; Saltzman, Daniel H; Fox, Nathan S

    2017-11-01

    The objective was to identify risk factors associated with blood transfusion in patients undergoing high-order Cesarean delivery (CD). This was a retrospective cohort study of patients undergoing third or more CD by a single maternal-fetal medicine practice between 2005 and 2016. We compared risk factors between women who did and did not receive a red blood cell transfusion during the operation or before discharge. Repeat analysis was performed after excluding women with placenta previa. A total of 514 patients were included, 18 of whom (3.5%; 95% confidence interval [CI], 2.2%-5.5%) received a blood transfusion. Placenta previa was the most significant risk factor for transfusion (61.1% of patients who received a transfusion vs. 1% of patients who did not; p blood transfusion. After women who had placenta previa were excluded, the incidence of blood transfusion was seven of 498 (1.4%; 95% CI, 0.7%-2.9%). Risk factors significantly associated with blood transfusion in the absence of previa were prophylactic anticoagulation during pregnancy and having labored. The incidence of transfusion in patients with no placenta previa, no anticoagulation, and no labor was 0.7% (95% CI, 0.3%-2.1%). Placenta previa was the most predictive risk factor for transfusion with a positive predictive value of 68.8% and a negative predictive value of 98.4%. In patients undergoing a third or more CD, only placenta previa, prophylactic anticoagulation during pregnancy, and having labored are independently associated with requiring a blood transfusion. These data can be used to guide physician ordering of prepared blood products preoperatively. © 2017 AABB.

  5. El proyecto de El Berrocal: síntesis preliminar

    Directory of Open Access Journals (Sweden)

    Pardillo, J.

    1993-08-01

    mineralización filoniana epitermal de uranio. El objetivo del proyecto es conocer los aspectos estructurales, litológicos, geoquímicos, hidroquímicos e hidrogeológicos del sistema granito-mineralización de U, a fin de establecer un modelo de migración de los radionucleidos naturales del medio. La convergencia de procesos tectónicos, hidrotermales y supergénicos ha dado lugar a sucesivas removilizaciones del uranio durante las fases deutérica, hidrotermal y supergénica, que afectaron al sistema. Estas fases son las responsables de la mineralogía y distribución actual de dicho elemento en el sistema. La removilización del torio es mucho más restringida debido a su diferente comportamiento geoquímico. Los procesos actuales de interacción agua-roca están condicionando los tipos de aguas existentes en el sistema que son: sulfatadas, en las zonas más superficiales y bicarbonatadas cálcicas, en las más profundas. Los contenidos en uranio en estas aguas están comprendidos entre 1 y 100 ppb. La hidrogeología de la zona está controlada, a nivel local, por la topografía y la red de fracturación, siendo el dique de cuarzo mineralizado un accidente con repercusión importante en la circulación de las aguas subterráneas. El análisis isotópico de las series del uranio y del torio en rellenos fisurales parece indicar procesos recientes de sorción-desorción de uranio y coprecipitación con carbonatos.

  6. Características musculares y producción de fuerza máxima/explosiva durante acciones isométricas/dinámicas de los músculos extensores de los miembros inferiores en jóvenes no entrenados

    OpenAIRE

    Izquierdo, M.; Aguado, X.; González, J. L.; López, J. L.; Ribas, T.; Linares, F.; Vila, L.; Voces, J. A.; Álvarez, A. I.; Prieto, J. G.

    1997-01-01

    Participaron en el estudio, de forma voluntaria cinco sujetos de sexo masculino, estudiantes de educación Física (22-26 años). El objetivo fue observar las relaciones entre el test de salto horizontal con los tests de salto vertical con contramovimiento y con flexión previa, tests de fuerza isométrica máxima y la distribución de los tipos de fibras musculares. Los resultados en la distancia y altura de vuelo conseguidas en los tests de salto horizontal, salto desde flexión previa sin cont...

  7. Formación cognoscitiva y rendimiento táctico

    OpenAIRE

    Solà Santesmases, Josep

    1998-01-01

    Este trabajo experimental trata de demostrar que la formación cognoscitiva previa (variable independiente) a la acción táctica deportiva (variable dependiente) es significativamente positiva para el correcto desarrollo de la misma. Esta formación cognoscitiva previa consistirá en la muestra de gráficos y dibujos de los movimientos tácticos a realizar. De esta manera, se ofrece a cada jugador del grupo experimental el conocimiento cognoscitivo que tendrá que guiar sus acciones tácticas en el j...

  8. The Determination of the Half-Life of U{sup 238} by Absolute Counting of {alpha} Particles in a 4 {pi}-Liquid Scintillation Counter; Determination de la periode de l'U{sup 238} au moyen du comptage absolu de particules {alpha} dans un comtpeur 4 {pi} a scintillateur liquide; Opredelenie perioda poluraspadda U{sup 238} posredstvom absolyutnogo scheta {alpha}-chastits v zhidkostnom stsintillyatsionnom schetchike 4 {pi}; Determinacion del periodo del U{sup 238} por recuento absoluto de las particulas {alpha} con un contador 4 {pi} de centelleador liquido

    Energy Technology Data Exchange (ETDEWEB)

    Steyn, J; Strelow, F W. E. [Council of Scientific and Industrial Research, Pretoria (South Africa)

    1960-06-15

    The specific activity of natural uranium was determined by liquid scintillation {alpha}-counting. Uranium was extracted from its decay products by methyl isobutyl ketone extraction and samples of this solution were added directly to the liquid scintillator. A quantitative investigation was made of the separation of uranium from thorium by the extraction method employed. Assuming that U{sup 238} and U{sup 234} were in equilibrium, and correcting for the presence of U{sup 235}, the specific activity and the half-life of the isotope U{sup 238} were calculated. (author) [French] L'activite specifique de l'uranium naturel est determinee au moyen d'un comptage a par scintillateur liquide. L'uranium est separe de ses produits de desintegration par une extraction a la methylisobutylceton e et des echantillons de cette solution sont ajoutes directement au scintillateur liquide. On fait une etude quantitative de la separation de l'uranium et du thorium par le procede d'extraction utilise. En admettant que U{sup 238} et U{sup 234} sont en equilibre et en faisant la correction voulue pour tenir compte de la presence de U{sup 235}, on calcule l'activite specifique et la periode de U{sup 238}. (author) [Spanish] La actividad especifica del uranio natural se determino con un contador {alpha} de centelleador liquido. El uranio se separo de productes de desintegracion por extraccion con metilisobutilcetona, y muestras de esta solucion se anadieron directamente al centelleador liquido. Se estudio cuantitativament e el grado de separacion uranio/torio alcanzado con el metodo de extraccion empleado. Introduciendo correcciones para tener en cuenta la presencia de U{sup 235}, se calculo la actividad especifica y el periodo de semidesintegracio n del U{sup 238} suponiendo que este isotopo se encontraba en equilibrio con el U{sup 234}. (author) [Russian] Spetsificheskaya aktivnost' estestvennogo urana byla opredelena s pomoshch'yu zhidkostnogo stsintillyatsionnog o schetchika {alpha

  9. The Association Between Interpersonal Relationships and the Mental and Physical Health of Postpartum Active Duty Military Women

    Science.gov (United States)

    2011-05-25

    diabetes , preeclampsia, placenta previa, placental abruption, and anemia, and these complications may have lasting effects (Adams et al., 1993...8217l’o: Chair, Insti tutional Review Soard 24 SEP 0? Subj : REQUEST TO ADD/ MODI FY RECRUITMENT BROCHURES INMCS0.2007.01C)2 Encl : (1) Recruitment Pos

  10. 77 FR 19155 - Federal Motor Vehicle Safety Standards; Seat Belt Assembly Anchorages; Incorporation by Reference

    Science.gov (United States)

    2012-03-30

    ... LeSabre, MY 2002 Toyota MR-2, MY 1995 Plymouth Neon, MY 1995 Toyota Previa, MY 2000 Chevrolet S-10, MY... FAD2 2005 VW Passat Pass Pass. 2005 Acura RL Pass Pass. 2005 Toyota Avalon Pass Pass. 2005 Buick... levels of government.'' NHTSA rules can preempt in two ways. First, the National Traffic and Motor...

  11. Placenta accreta: MRI antenatal diagnosis and surgical correlation.

    Science.gov (United States)

    Ha, T P; Li, K C

    1998-01-01

    We describe a case of a placenta previa accreta that was diagnosed antenatally by MRI with subsequent surgical confirmation. We show the advantages of ultrafast MRI single shot (SS) fast spin echo (FSE) techniques for accurate diagnosis with minimal scan time and fetal motion artifacts.

  12. Cesarean scar defects and placental abnormalities; a 3 year survey study

    Directory of Open Access Journals (Sweden)

    Denisa O. Bălălău

    2017-10-01

    Full Text Available The placenta is an essential organ for embryonic and fetal development, ensuring nutrient uptake, gas exchange (via the mother's blood supply, waste elimination, thermo-regulation, immunological and hormonal factors, etc. The most common placental abnormalities are represented by placenta previa, and a morbidly adherent placenta (in the form of accreta, increta, and percreta placenta. This study was performed on a sample of 99 patients diagnosed with abnormalities of placentation who underwent cesarian delivery during a period of 3 years in Bucur Maternity Hospital. Seven patients were diagnosed with morbidly adherent placenta (5 accreta and 2 percreta subtypes, the others having placenta previa (65 with lateral disposition, 18 marginal, and 9 central insertion. All patients had been diagnosed by ultrasound (which was also used for general monitoring, being confirmed during operation and histopathologically. Complications required 4 emergency peripartum hysterectomies, with no maternal mortality but with fetal death in one case. The research literature shows that about half of women with placenta previa have several episodes of bleeding, being the leading cause of antepartum hemorrhage. For some women with placenta previa/accrete, hemorrhaging is severe and requires hysterectomy as a necessary step to control the life-threatening situation. Thus, such patients should be carefully monitored to avoid as much as possible the medical, social, and psychological implications of this critical therapeutic procedure.

  13. Montelukast reduces asthma exacerbations in 2- to 5-year-old children with intermittent asthma

    DEFF Research Database (Denmark)

    Bisgaard, Hans; Zielen, Stefen; Garcia-Garcia, María Luz

    2005-01-01

    The PREVIA study was designed to investigate the role of montelukast, a leukotriene receptor antagonist, in the prevention of viral-induced asthma exacerbations in children aged 2 to 5 years with a history of intermittent asthma symptoms. The study was a 12-month multicenter, double-blind, parall...

  14. Protracted People’s War in the Philippines: A Persistent Communist Insurgency

    Science.gov (United States)

    2007-03-01

    regarding both public and private sector corruption within Metro Manila, Metro Cebu and Metro Davao, Cavite- Laguna -Batangas, and Cagayan de Oro...his family such as a Toyota Previa, a Mitsubishi L-300 Van de Luxe, and a 1997 Honda Civic. Additionally, deposits and investments he made in the

  15. Repercusión de los esguinces de tobillo sobre el equilibrio postural

    Directory of Open Access Journals (Sweden)

    Laura Martín-Casado

    2015-09-01

    Full Text Available Objetivo. Analizar las diferencias intrasujeto en el equilibrio postural durante la realización de test de equilibrio estáticos y dinámico – funcionales, entre una extremidad que presentó signo de bostezo articular en el tobillo, fruto de una lesión previa de esguince lateral, frente a una extremidad sin bostezo.

  16. Los refranes en el quijote (Estudio critico de la traducción al esloveno

    Directory of Open Access Journals (Sweden)

    Juan Carlos Oven

    1991-12-01

    Full Text Available Antes de afrontar el tema de los refranes en el Quijote será útil acercarnos a este campo específico de la literatura con algunasconsideraciones previas que nos ayuden a iluminar determinados aspectos de este estudio.

  17. Impact of Cesarean Section Number on Maternal and Obstetric Outcome

    Directory of Open Access Journals (Sweden)

    Deniz Arıkan

    2009-12-01

    CONCLUSION: Among the causes of morbidity clinically most important was the triad of placenta previa, placenta accreta and hysterectomy, was also responsible for the most serious risk to the mother with increasing number of C/S.

  18. Immobilization of preconditioned spent fuel from nuclear research reactors in a ceramic matrix

    International Nuclear Information System (INIS)

    Russo, Diego O.; Rodriguez, Diego S.; Heredia, Arturo D.; Sanfilippo, Miguel; Sterba, Mario E.; Mateos, Patricia

    2002-01-01

    The fuel elements from nuclear research reactors consist in a laminated sandwich of aluminum with a core of some uranium compound. To process this material its necessary to previously eliminate the aluminum covering the fuel, before the conditioning of the rest of the fuel in a stable matrix, in order to obtain an acceptable waste form for a subsequent disposition in a geological repository. Normally, mechanical and chemical methods are proposed for that purpose. One of the most developed techniques for immobilization of the radioactive elements above mentioned, is the vitrification. In this work we propose a method named CERUS (in Spanish Ceramizacion de Elementos Radiactivos con Uranio Sinterizado - Ceramization of radioactive elements with sintered uranium). This is a sinterization of the pre-treated fuel elements mixed with natural uranium oxide. The properties of the blocks obtained are adequate for final disposal in a deep geological reservoir. (author)

  19. Lithium extractive metallurgy

    International Nuclear Information System (INIS)

    Josa, J.M.; Merino, J.L.

    1985-01-01

    The Nuclear Fusion National Program depends on lithium supplies. Extractive metallurgy development is subordinate to the localization and evaluation of ore resources. Nowadays lithium raw materials usable with present technology consist of pegmatite ore and brine. The Instituto Geologico y Minero Espanol (IGME) found lepidolite, ambligonite and spodrimene in pegmatite ores in different areas of Spain. However, an evaluation of resources has not been made. Different Spanish surface and underground brines are to be sampled and analyzed. If none of these contain significant levels of lithium, the Junta de Energia Nuclear (JEN) will try an agreement with IGME for ENUSA (Empresa Nacional del Uranio, S.A.) to explore pegmatite-ore bodies from different locations. Different work stages, laboratory tests, pilots plants tests and commercial plant, are foreseen, if the deposits are found. (author)

  20. Las negociaciones con Irán sobre la cuestión nuclear

    Directory of Open Access Journals (Sweden)

    José Antonio Sainz de la Peña

    2012-05-01

    Full Text Available El artículo expone de forma resumida las conversaciones recientes entre Irán y la AIEA y el G5+1, mostrando las posiciones y las dificultades para alcanzar un acuerdo sobre el programa nuclear iraní. Las sanciones tienen, a su vez importantes efectos en la economía iraní, pero no está claro que Irán esté dispuesto a ceder en su programa de enriquecimiento de uranio, ni que se hayan adoptado por ambas partes o se puedan adoptar serias medidas de fomento de confianza, estando ya Irán bajo crecientes sanciones y no habiendo clarificado por completo su programa nuclear.

  1. On the Conversion of UF{sub 6} to UO{sub 2}; Conversion de UF{sub 6} en UO{sub 2}; O prevrashchenii UF{sub 6} v UO{sub 2}; Transformacion del UF{sub 6} en UO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Kolar, D.; Slivnik, J.; Volavsek, B. [Jozef Stefan Nuclear Institute, Ljubljana, Yugoslavia (Slovenia)

    1963-11-15

    A complex ammonium uranium fluoride was prepared by the reduction of uranium hexafluoride with ammonia in the gaseous phase at 40 deg. C. The very fine product was retained in electrical precipitators and converted into uranium dioxide by pyrohydrolysis with water vapour and hydrogen in the temperature interval between 500 and 600 deg. C. The reaction was followed by differential thermal and thermogravimetrical analysis. The uranium dioxide was analysed for fluorine and oxygen content and the crystal structure was checked by X-ray analysis. Several physico-chemical characteristics, such as specific surface area, particle size and tap density of the powder, have been determined. From the powder, the pellets have been pressed and sintered at 1350 deg. C. Depending on the various conditions of preparation, densities up to 94% of the theoretical values were achieved. (author) [French] Les auteurs ont prepare un fluorure complexe d'uranium et d'ammonium par reduction d'hexafluorure d'uranium avec du gaz ammoniac a 40 deg. C. Le produit obtenu, tres fin, a ete retenu dans des precipitateurs electriques et transforme en bioxyde d'uranium par hydrolyse a chaud avec de la vapeur d'eau et de l'hydrogene, a des temperatures se trouvant entre 500 et 600 deg. C. La reaction a ete suivie d'une analyse thermique et thermogravimetrique differentielle. Les auteurs ont aussi analyse le bioxyde d'uranium pour determiner la teneur en oxygene et en fluor et ils ont verifie la structure des cristaux par une analyse aux rayons X. Ils ont determine plusieurs caracteristiques physico-chimiques de la poudre, telles que la surface specifique, la grosseur des particules et la densite apparente apres vibration. A partir de cette poudre, les pastilles ont ete frittees sous pression a 1350 deg. C. Les densites obtenues atteignaient 94% des valeurs theoriques, suivant les diverses conditions de preparation. (author) [Spanish] Los autores prepararon un fluoruro de uranio y amonio complejo por

  2. Development of a dry transport and storage cask for spent LWR fuel assemblies in Spain

    International Nuclear Information System (INIS)

    Melches, C.; Uriarte, A.; Espallardo, J.A.

    1982-01-01

    One of the advantages of the cask storage concept is its flexibility which makes it specially attractive in the case of the Spanish circumstances. For these reasons the Empresa Nacional del Uranio, S.A. (ENUSA), Junta de Energia Nuclear (JEN) and Equipos Nucleares, S.A. (ENSA) initiated in 1981 a joint program for the development of a prototype cask for the dry transport and storage of spent fuel assemblies. This program includes as main steps the analysis of the conceptual design, the detailed design and experimental tests, the fabrication of a prototype and its licencing and safety testing. The mentioned program, which started in the early 1981, is scheduled to be completed at the end of 1984

  3. Sonetos

    Directory of Open Access Journals (Sweden)

    Milan Jesih

    1996-12-01

    Full Text Available Poeta, dramaturgo y traductor Milan Jesih nació el 14 de abril de 1950. Estudió Literatura comparada en Ljubljana. Ha sido miembro del grupo vanguardista 442. Vive en Ljubljana. Su primer libro de poesía se publica en el año 1972 bajo el título Uran v urinu, gospodar! (iUranio en la orina, señor!. A este le siguen: Legende (1974, Leyendas, Kobalt (1976, Cobalto, Volfram (1980, Volframio, Usta (1985, Boca, Soneti (1989, Sonetos, Soneti drugi (1993, Sonetos segundos. Su poesía se basa en los juegos de palabras, sonoridad enfatizada, ironía, sátira y parodia, sus últimos libros de poesía estan dedicados al soneto

  4. Cerus process modified with glass addition (Vitrocerus)

    International Nuclear Information System (INIS)

    Arboleda, P.A.; Rodriguez, D.S.; Prado, M.O.

    2009-01-01

    A processing method for spent fuels type Mtr from research reactors has developed in Nuclear Materials Division of Bariloche Atomic Center, this process involved the creation of ceramic matrix containing fuel and natural uranium in an isotopic solution, this project has named CERUS (Spanish acronym of 'Ceramización de Elementos Radioactivos en Uranio Sinterizado': Ceramming of radioactive elements with sintered uranium ). This process works with reduced volumes than a conventional vitrification, however because of some issues on the material resistance; we propose the addition of small amounts of glass with the idea to enhance the lixiviation properties of the final material. In this process is not considered the reprocessing possibility of the spent fuel. (author)

  5. Chemical process for recovery of uranium values contained in phosphoric mineral lixivia

    International Nuclear Information System (INIS)

    Conceicao, E.L.H. da; Awwal, M.A.; Coelho, S. V.

    1980-01-01

    A recovery process of uranium values from phosporic mineral lixivia for obtaining uranio oxide concentrate adjusted to specifications of purity for its commercialization the process consists of the adjustment of electromotive force of lixiviem to suitable values for uranium extraction, extraction with organic solvent containing phosphoric acid ester and oxidant reextraction from this solvent with phosphoric acid solution, suggesting a new solvent extraction containing synergetic mixture of di-2-ethyl hexyl phosphoric acid and tri-octyl phosphine, leaching this solvent with water and re-extraction/precipitation with ammonium carbonate solution, resulting in the formation of uranyl tricarbonate and ammonium, that by drying and calcination gives the uranium oxide with purity degree for commercialization. (M.C.K.) [pt

  6. Preliminary evaluations of social and environmental impacts from mine-industrial project - uranium of Lagoa Real, Bahia, Brazil

    International Nuclear Information System (INIS)

    Negrao, F.I.; Oliveira, G.G. de; Zanetti, J.C.; Cunha, R.P.P. da.

    1990-01-01

    The Uranium Province of Lagoa Real is situated in the central south of the State of Bahia and constitutes at the moment the second uranium resource of Brazil, containing, in several anomalies, as available resource, 93.850 ton. of U sub(3) O sub(8). The Uranio do Brasil S.A. develops a mine-industrial complex in this Province with the aim to extract and benefit uranium and intending to improve in 1992. The project is considered with high hazard, because involves te management of radioactive material, and becomes necessary an available of environmental impact, in accordance with CONAMA 001/86 and an active participation of the society. This paper aims to indentify the social and environmental impacts of this process, as a contribution of this important discussion. (author)

  7. Experiments by the Mexican NNEC on the Control of Airborne Radioactive Contamination; Experiencias Realizadas en la CNEN de Mexico Sobre El Control de Contaminaciones Radiactivas Arrastradas por el Aire

    Energy Technology Data Exchange (ETDEWEB)

    Bravo S, E. [Comision Nacional de Energia Nuclear, Mexico D.F. (Mexico)

    1968-12-15

    The installations of the Mexican National Nuclear Energy Commission have to deal with the problem of environmental contamination caused by dust and aerosols suspended in the air and originating mainly with such uranium-bearing ores as tyuyamunite, carnotite, betafite, technical-grade sodium uranate, ammonium uranate concentrate, uranium tetrafluoride and uranium dioxide. To prevent environmental contamination by these radioactive materials, the Commission has experimented with three different systems, based on the principle of extracting the dust from the environment, passing it through a cyclone system, separating the particles of larger size and controlling the small particles or aerosols by means of filtration, dilution in liquid columns and dilution in liquid curtains. On the basis of the results obtained, plans have been made for supplementing the systems with an adsorption column and an ion exchange column, depending on the specific requirements of each laboratory. (author) [Spanish] En las instalaciones de la Comision Nacional de Energia Nuclear de Mexico existe el problema de la contaminacion ambiental producida por polvos y aerosoles suspendidos en el aire, de minerales uraniferos tales como tyuyamunita, carnotita, betafita, uranato de sodio tecnico, concentrado de uranato de amonio, tetrafluoruro de uranio y bioxido de uranio fundamentalmente. Para evitar dicha contaminacion del medio ambiente con los materiales radiactivos mencionados, se han experimentado tres diferentes sistemas cuyo principio consiste en la extraccion de los polvos del medio ambiente, pasandolos a un sistema de ciclon, separando las particulas de mayor tamano y controlando las particulas pequenas o aerosoles por medio de filtracion, dilucion en columnas liquidas y dilucion en cortinas liquidas. Sobre la base de los resultados obtenidos se ha proyectado completar los sistemas de acuerdo a las necesidades especificas de cada laboratorio con una columna de adsorcion y otra de intercambio

  8. Acciones de rehabilitación frente a la entrada de gas radón Rehabilitation Measures against radon gas entry

    Directory of Open Access Journals (Sweden)

    Borja Frutos Vázquez

    2011-01-01

    Full Text Available El gas radón es un agente patológico para los usuarios de los edificios en donde se manifiesta su presencia. Por su origen, en la cadena de desintegración del uranio, conlleva efectos radiactivos que, en el organismo humano, determinan un aumento de riesgo en la generación de cáncer pulmonar. Procedente de suelos donde hay masas de granito u otros sustratos con contenidos de uranio, penetra a través de los materiales habitualmente usados en la construcción; como es el caso de las soleras de hormigón, muros de sótano, etc. Para impedir la inmisión de este gas en los espacios habitados, se pueden considerar varias actuaciones en edificios ya construidos. El objeto de este trabajo consiste en mostrar los resultados sobre reducciones de radón conseguidas por distintas soluciones constructivas que se han diseñado y ejecutado con el fin de frenar la inmisión de gas radón al interior de un prototipo de vivienda construido al efecto.Radon gas is a pathological agent for inhabitants of buildings where it is present. Due to its origin in uranium decay chain, it bears radioactive effects that inside human body lead to higher risks of developing lung cancer. It comes from soils containing granite masses or other substrates containing uranium. It enters through common material used in constructions, such as concrete ground slabs, basement walls, etc. In order to avoid such gas immission into inhabited rooms, several measurements cab be considered for existing buildings. This study intends to show the results obtained for radon reductions by means of different constructive solutions, already designed and executed so as to stop radon gas immission into a prototype building constructed for this specific purpose.

  9. El gas radón como contaminante atmosférico

    Directory of Open Access Journals (Sweden)

    Luis Santiago Quindós Poncela

    2010-12-01

    Full Text Available En este trabajo se abordan distintos aspectos acerca de la problemática del radón en viviendas. Este gas de origen natural se encuentra prácticamente en la totalidad de los suelos de la corteza terrestre debido a la presencia de uranio y radio en la composición de los mismos. En función de factores arquitectónicos y de hábitos de ocupación de la vivienda pueden alcanzarse concentraciones elevadas del gas en interiores. En estas situaciones existe un incremento cuantificable del riesgo de desarrollar cáncer de pulmón en los habitantes de la vivienda. En los últimos años, las mejoras metodológicas en la realización de estudios epidemiológicos han conducido a la obtención de evidencias científicas de la relación entre la presencia de radón en interiores y el riesgo de cáncer de pulmón. Esta relación, encontrada hace años en trabajadores de minas de uranio, ha sido corroborada en el caso del radón residencial a la luz de los metaanálisis realizados recientemente a partir de estudios epidemiológicos agrupados. Durante los últimos 25 años se han realizado más de 6.000 medidas de radón en interiores. Se presentan los principales resultados de las mayores campañas de medida llevadas a cabo, así como los criterios recientemente establecidos por el Consejo de Seguridad Nuclear acerca de los niveles de intervención en viviendas y lugares de trabajo.

  10. Soluble FLT-1 rules placental destiny.

    Science.gov (United States)

    Yamashita, Michiko; Kumasawa, Keiichi; Nakamura, Hitomi; Kimura, Tadashi

    2018-02-19

    Placenta previa is an abnormality in which the placenta covers the internal uterine os, and it can cause serious morbidity and mortality in both mother and fetus due to catastrophic hemorrhage. Some pregnant women recover from placenta previa due to a phenomenon called "migration." However, the mechanism of "migration" of the placenta has not been elucidated. Human placentas were collected from patients with placenta previa and those with no abnormal placentation (control). A microarray analysis was performed to detect the genes up- or down-regulated only in the caudal part in the previa group. Specific mRNA expression was evaluated using real-time quantitative reverse transcription PCR (qRT-PCR). Unilateral uterine artery ablation of 8.5 dpc mice was performed to reproduce the reduction of placental blood supply, and weights of the placentas and fetuses were evaluated in 18.5 dpc. Specific mRNA expression was also evaluated in mice placentas. According to the result of the microarray analysis, we focused on soluble fms-like tyrosine kinase-1 (sFLT-1) and hypoxia-inducible factor-1 (HIF-1) alpha. The sFLT-1 expression level is locally high in the caudal part of the human placenta in patients with placenta previa. In mice experiments, the weights of the placentas and fetuses were significantly smaller in the ablation side than those in the control side, and the sFlt-1 expression level was significantly higher in the ablation side than in the control side. Our study suggests that "migration" of the placenta is derived from placental degeneration at the caudal part of the placenta, and sFlt-1 plays a role in this placental degeneration. Copyright © 2018 Elsevier Inc. All rights reserved.

  11. Maternal plasma levels of cell-free β-HCG mRNA as a prenatal diagnostic indicator of placenta accrete.

    Science.gov (United States)

    Zhou, J; Li, J; Yan, P; Ye, Y H; Peng, W; Wang, S; Wang, X Tong

    2014-09-01

    Several biomarkers, including maternal serum creatinine kinase and α-fetoprotein, have been described as potential tools for the diagnosis of placental abnormalities. This study aimed to determine whether maternal plasma mRNA levels of the β subunit of human chorionic gonadotropin (β-HCG) could predict placenta accreta prenatally. Sixty-eight singleton pregnant women with prior cesarean deliveries (CDs) were classified into three groups: normal placentation (35 women, control group); placenta previa alone (21 women, placenta previa group); and both placenta previa and placenta accreta (12 women, placenta previa/accreta group). Maternal plasma concentrations of cell-free β-HCG mRNA were measured by real-time reverse-transcription polymerase chain reaction and were expressed as multiples of the median (MoM). Cell-free β-HCG mRNA concentrations (MoM, range) were significantly higher in women with placenta accreta (3.65, 2.78-7.19) than in women with placenta previa (0.94, 0.00-2.97) or normal placentation (1.00, 0.00-2.69) (Steel-Dwass test, P accreta group, the concentration of cell-free β-HCG mRNA was significantly higher among women who underwent CDs with hysterectomy (4.41, 3.49-7.19) than among women whose CDs did not result in hysterectomy (3.20, 2.78-3.70) (Mann-Whitney U test, P = 0.012). An increased level of cell-free β-HCG mRNA in the maternal plasma of women with placenta accreta may arise from direct uteroplacental transfer of cell-free placental mRNA molecules. The concentration of cell-free β-HCG mRNA in maternal plasma may be applicable to the prenatal diagnosis of placenta accreta, especially to identify women with placenta accreta likely to require hysterectomy. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. An Appraisal of Analytical Methods for Plutonium and their Applications to the Analysis of Nuclear Materials; Evaluation des Methodes Analytiques de Dosage du Plutonium et de Leur Application a l'Analyse des Matieres Nucleaires; Otsenka analiticheskikh metodov opredeleniya plutoniya i ikh primenenie dlya analiza yadernykh materialov; Metodos Analiticos de Determinacion del Plutonio y su Empleo en el Analisis de Materiales Nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Milner, G. W.C.; Phillips, G. [Atomic Energy Research Establishment, Harwell, Berks. (United Kingdom)

    1966-02-15

    respectifs de la dissolution dans des melanges d'acides mineraux courants et de la dissolution faisant appel a des procedes de fusion, avec des exemples a l'appui. Les auteurs decrivent aussi les procedes utilises et les resultats obtenus, pour l'analyse des alliages Pu-U, Pu-Ce-Co et Pu-U-Mo, des oxydes et carbures de Pu-U, et des cermets de carbure de Pu-U contenant Fe, Mo et Cr. Ces matieres sont l'aboutissement de recherches metallurgiques destinees a mettre au point des combustibles nucleaires. (author) [Spanish] Para determinar el contenido de plutonio de los materiales nucleares existen diversos metodos. Si se trata de cantidades del orden del miligramo se pueden emplear la espectrofotometria diferencial por el color del Pu (III), la gravimetria basada en el PuO2{sub ,} si recuento gamma y metodos de oxidorreduccion como las valoraciones potenciometricas o amperimetricas y la culombiometria de potencial controlado. Si se trata de microgramos son preferibles el recuento alfa, la dilucion isotopica o las tecnicas polarograficas. Teniendo en cuenta que unos metodos son mas adecuados que otros para ciertos tipos de muestra, el analista tiene que resolver un dificil problema de seleccion a fin de obtener ios mejores resultados posibles. Los autores exponen las ventajas y las limitaciones puestas de manifiesto por los anos de experiencia en la A.E.R.E. y formulan observaciones acerca de la exactitud y la precision de los metodos, su sensibilidad y otras cuestiones de especial interes. Como algunos de esos metodos exigen la separacion previa del plutonio, los autores estudian el empleo de las tecnicas de intercambio anionico y de cromatografia en fase inversa, y en particular su conveniencia para el analisis de muestras radiactivas. Examinan los muchos problemas que han surgido al analizar por estos metodos, aleaciones, productos ceramicos y cermets de plutonio en diversos sistemas que contenian uranio, torio, hierro, cromo, molibdeno, cerio y cobalto. La memoria trata

  13. The Problem of Storing Fission Products Arising from the Processing of Irradiated Uranium-Molybdenum Alloys; Probleme du Stockage des Produits de Fission en Provenance du Traitement des Alliages Uranium-Molybdene Irradies; 041f 0420 041e 0411 041b 0415 041c 0410 0425 0420 0410 041d 0415 041d 0418 042f 041e 0422 0425 041e 0414 041e 0412 041f 041e 0421 041b 0415 041f 0415 0420 0415 0420 0410 0411 041e 0422 041a 0418 041e 0411 041b 0423 0427 0415 041d 041d 041e 0413 041e 0421 041f 041b 0410 0412 0410 0423 0420 0410 041d - 041c 041e 041b 0418 0411 0414 0415 041d ; El Problema del Almacenamiento de los Productos de Fision Procedentes del Tratamiento de las Aleaciones Uranio-Molibdeno Irradiadas

    Energy Technology Data Exchange (ETDEWEB)

    Faugeras, P.; Kikindai, T. [Commissariat a l' Energie Atomique, Paris (France)

    1963-02-15

    Uranium-molybdenum alloys are of value thanks to their in-pile behaviour but serious disadvantages arise in connection with the storing of fission products resulting from the processing of these alloys. Because of the insolubility of molybdenum it is impossible to concentrate a solution of fission products by evaporation, and for this reason we have directed our efforts towards the solubilization of molybdenum through the addition of reagents such as iron or phosphoric ions. In this way one can obtain final solutions of 60 g/l Mo with Fe 100 g/l Mo with PO{sub 4}H{sub 3}. The volumes to be stored are still considerable (especially with Fe) and the possibility of nitrate calcination in a fluidized bed was considered. The reaction takes place at about 400 Degree-Sign C. The behaviour of the ruthenium and the friability of the calcined solid (formation of considerable amounts of fine material) have led us to abandon this process in favour of the preparation of phosphate glasses. (author) [French] Les alliages U-Mo sont interessants par leur tenue en pile, mais ils presentent des inconvenients serieux quant au stockage des produits de fission resultant de leur traitement. L'insolubilite du molybdene interdit toute concentration par evaporation de la solution de produits de fission. C'est pourquoi les auteurs ont oriente leurs etudes vers la solubilisation du molybdene par addition de reactifs tels que le fer ou les ions phosphoriques. Ainsi, on peut obtenir les solutions finales a 60 g/l Mo avec Fe, 100 g/l Mo avec PO{sub 4}H{sub 3} Les volumes a stocker sont encore importants (surtout avec Fe) et la calcination des nitrates dans un lit fluidise a ete etudiee. La reaction a lieu vers 400 Degree-Sign C. Le comportement du ruthenium et la friabilite du solide calcine (formation importante de fines) a conduit a abandonner ce procede au profit de la confection de verres phosphates. (author) [Spanish] Las aleaciones U-Mo son interesantes por la forma en que se comportan en el reactor, pero presentan serios inconvenientes en lo que respecta al almacenamiento de los productos de fision resultantes de su tratamiento. La insolubilidad del molibdeno impide concentrar por evaporacion las soluciones de los productos de fision. Por tal motivo, los autores han estudiado la posibilidad de solubilizar el molibdeno agregandole reactivos tales como el hierro o los iones fosforicos. De este modo, es posible obtener soluciones finales de 60 g/l Mo con hierro, 100 g/l Mo con PO{sub 4}H{sub 3}. Los volumenes que es preciso almacenar siguen siendo importantes (sobre todo con el hierro) y por eso se ha estudiado la calcinacion de los nitratos en un lecho fluidizado. La reaccion tiene lugar a los 400 Degree-Sign C aproximadamente. El comportamiento del rutenio y la friabilidad del solido calcinado (importante formacion de particulas menudas) ha inducido a los autores a reemplazar este procedimiento por el de preparacion de vidrios fosfAtados. (author) [Russian] Povedenie splavov uran-molibden v reaktore predstavljaet prakticheskij interes. Odnako voznikaet problema hranenija produktov delenija, kotorye poluchajutsja v rezul'tate ih pererabotki. V tom sluchae, kogda molibden nahoditsja v nerastvorennom sostojanii, ljuboe koncentrirovanie produktov delenija putem isparenija rastvora prakticheski nevozmozhno. Vot pochemu my orientirovalis' na izuchenie rastvorenija mo'libdena pribavleniem takih reagentov, kak zhelezo idi fosfat-iony. Mozhno poluchit' rastvor sostava: 60 g/l Mo s Re ili. 100 g/l Mo sPO{sub 4}H{sub 3} V jetom sluchae ob'edy, prednaznachennye dlja hranenija, uvelichivajutsja (osobenno pri dobavlenii Fe). Bylo izucheno prokalivanie nitratov v dvizhushhemsja sdoe. Reakcija prohodit pri temperature okolo 400 Degree-Sign C. Letuchest' rutenija i hrupkost' tverdogo prokalennogo veshhestva (vsledstvie obrazovanija znachitel'nogo kolichestva uglja) zastavila'nas otkazat'sja ot'jetogo processa i'perejti k izgotovleniju fosfatnyh stekol. (author)

  14. Valoración Médica de Psitácidas y Primates Neotropicales

    OpenAIRE

    Nestor Varela

    2008-01-01

    La evaluación clínica comienza desde el proceso de recepción, ya que permite hacer una apreciación sobre la urgencia del problema, si es que la hay. Aunque no es común en la práctica con especies silvestres, la comunicación telefónica previa al arribo del animal al consultorio, es útil para recolectar información y para dar recomendaciones sobre el transporte del espécimen. En muchos casos la recolección previa de datos importantes no sólo es útil para realizar un examen adecuado, sino tambié...

  15. El regreso a la escuela: evidencias para México

    Directory of Open Access Journals (Sweden)

    Guadalupe Fabiola Pérez Baleón

    2014-01-01

    Full Text Available El regreso a la escuela es una transición que forma parte de las trayectorias escolares de una parte de la población mexicana. Puede ser un punto de inflexión en la vida de las personas y una estrategia de avance socioeconómico. Los factores positivamente asociados con este retorno son: ser joven, tener una escolaridad previa de secundaria o más, no estar casado, haber vivido en zonas urbanas, tener experiencia migratoria previa, tener padres profesionistas o que se dediquen a actividades no manuales y pertenecer a cohortes jóvenes. Hay algunas diferencias en las tendencias del retorno por género que se pueden explicar por la influencia de los roles tradicionales.

  16. Effect of maternal age on maternal and neonatal outcomes after assisted reproductive technology

    DEFF Research Database (Denmark)

    Wennberg, Anna Lena; Opdahl, Signe; Bergh, Christina

    2016-01-01

    weeks), low birth weight (LBW; mortality (≥28 weeks). Adjusted odds ratios (AORs) were calculated. Associations between maternal age and outcomes were analyzed. RESULT(S): The risk of placenta previa (AOR 4.11-6.05), cesarean delivery (AOR 1......OBJECTIVE: To compare the effect of maternal age on assisted reproductive technology (ART) and spontaneous conception (SC) pregnancies regarding maternal and neonatal complications. DESIGN: Nordic retrospective population-based cohort study. Data from national ART registries were cross.......18-1.50), PTB (AOR 1.23-2.19), and LBW (AOR 1.44-2.35) was significantly higher in ART than in SC pregnancies for most maternal ages. In both ART and SC pregnancies, the risk of HDP, placenta previa, cesarean delivery, PTB, LBW, and SGA changed significantly with age. The AORs for adverse neonatal outcomes...

  17. Effects of Interviewee's Job Experience and Gender on Ratings and Reliability in a Behavioral Interview

    Directory of Open Access Journals (Sweden)

    Beata Choragwicka

    2009-01-01

    Full Text Available En este artículo se analiza si el uso de la entrevista de descripción de conducta (EDC puede implicar discriminación indirecta. Doce entrevistados, 6 con previa experiencia laboral y 6 sin experiencia, la mitad de ellos hombres y la mitad mujeres, fueron evaluados mediante una EDC. Se han calculado las puntuaciones medias de los entrevistados, al igual que la fiabilidad interjueces de la entrevista, utilizando un panel de 12 y de 6 evaluadores. No se han encontrado diferencias significativas entre los entrevistados con y sin experiencia laboral previa, al igual que entre hombres y mujeres. Se debaten las implicaciones de estos resultados para el uso de la EDC en los procesos de selección de personal.

  18. Efecto del montelukast sobre la concentración de mediadores inflamatorios en el modelo de artritis gotosa múrida

    OpenAIRE

    Ponce, Loida; Bermúdez, Mariangélica; Miranda, Jorgelin; Verzura, Julie; Tovar, Robert; Corado, José

    2016-01-01

    El tratamiento de la artritis gotosa controla parcialmente la enfermedad con efectos secundarios importantes. El montelukast es un antagonista selectivo de los receptores de leucotrienos LTD4, útil en el tratamiento de rinitis alérgica y asma bronquial. Investigaciones previas han reportado un potente efecto antiinflamatorio de montelukast en el modelo de artritis gotosa múrida. Este estudio investigó el efecto de montelukast sobre la concentración de leucotrienos cisteinil y LTB4, interleuci...

  19. Procesos de ozonación fotocatalítica para eliminar contaminantes emergentes de aguas residuales urbanas

    OpenAIRE

    Espejo Morán, María Azahara

    2016-01-01

    En este trabajo se ha estudiado la degradación de distintos contaminantes emergentes (CEs) añadidos a un agua residual urbana mediante procesos químicos integrados secuencialmente como etapa previa o etapa terciaria a un tratamiento biológico aerobio convencional por fangos activos. Los compuestos seleccionados son acetaminofeno, antipirina, bisfenol A, cafeína, carbamazepina, diclofenaco, hidroclorotiazida, ketorolaco, metoprolol, sulfametoxazol y testosterona. Estos CEs se eligieron ya que ...

  20. Real increasing incidence of hysterectomy for placenta accreta following previous caesarean section.

    LENUS (Irish Health Repository)

    Higgins, Mary F

    2013-11-01

    Placenta accreta, morbid adherence to the uterus to the myometrium, is commonest in association with placenta previa in women previously delivered by caesarean section (CS). It has become proportionally a greater cause of major maternal morbidity and mortality as the frequency of other serious obstetric complications has declined. The aim of this study was to examine the incidence of placenta accreta in the context of a rising caesarean delivery rate.

  1. Obstetric management after infertility treatment

    African Journals Online (AJOL)

    Les mesures de résultat obstétriques analysés comprennent : les complications antenatal et des enfants, le nombre de bébés livrées et le mode de livraison. Les données a été entrées dans la base .... became pregnant after assisted reproduction.[9,10]. Intrapartum complications like placenta previa and placental abruption ...

  2. El discurso en la mirada: los Españoles y la visión del Tawantinsuyo

    Directory of Open Access Journals (Sweden)

    Martha Barriga Tello

    2011-05-01

    Full Text Available El estudio ofrece las diversas lecturas de los monumentos del Imperio Inca realizadas por los primeros españoles. Sus apreciaciones varían de acuerdo a su experiencia previa, sus conocimientos y aquello con que les era posible compararlos. La primera impresión quedará como eje para las opiniones que posteriormente ofrecerán en sus escritos.

  3. Una propuesta para la implementación de un Taller de Desarrollo de Proyectos en una carrera de Ingeniería en Informática bajo el Modelo por Competencias

    Directory of Open Access Journals (Sweden)

    López, Gustavo

    2010-01-01

    Full Text Available El presente trabajo propone una innovación curricular en cuanto al dictado de un Taller de Desarrollo de Proyectos, enfocado desde la perspectiva del Modelo por Competencias. Por tratarse el Taller de una asignatura de carácter integrador respecto de las asignaturas previas, se hace necesario definir Competencias que resulten también integradoras. Este es el desafío que enfrenta la presente propuesta.

  4. Predicción del riesgo individual de alto coste sanitario para la identificación de pacientes crónicos complejos

    Directory of Open Access Journals (Sweden)

    Jordi Coderch

    2014-07-01

    Conclusiones: El consumo sanitario elevado se relaciona con la morbilidad crónica compleja. Un modelo basado en la edad, la morbilidad y la utilización previa es válido para predecir el riesgo de alto consumo, y así identificar la población diana de estrategias de atención proactiva para pacientes crónicos complejos.

  5. Derecho a la consulta y participación de los pueblos indígenas, la experiencia constitucional en los casos de México y Chile

    OpenAIRE

    Rea Granados, Sergio Alejandro

    2015-01-01

    En este artículo se analiza la importancia y los retos de la constitucionalización de los derechos a la consulta previa y la participación de los pueblos indígenas en los casos de México y Chile. This article analyses the importance and challenges of rights to previous consultation and participation of indigenous peoples in the Constitution of Mexico and Chile.

  6. Research

    African Journals Online (AJOL)

    abp

    18 août 2013 ... Apoyo nutricional perioperatorio en pacientes con neoplasia colorrectal. Nutr Hosp. 2010; 25(5):. 797-805. PubMed| Google Scholar. 13. Cid Conde L, Fernández López T, Neira Blanco P, Arias Delgado. J et al. Prevalencia de desnutrición en pacientes con neoplasia digestiva previa cirugía. Nutr Hosp.

  7. OUTCOME OF PREGNANCIES COMPLICATED BY THREATENED ABORTION IN THE SECOND TRIMESTER OF PREGNANCY - PROSPECTIVE STUDY

    OpenAIRE

    Rajeswary

    2015-01-01

    AIM: To compare the outcome of pregnancies complicated by bleeding per vaginum between 14- 20 weeks with those not complicated by bleeding per vaginum before 20 weeks. To evaluate the potential determinants of outcome such as gestational age at bleeding, number of bleeding episodes, extent of placental separation or sub chorionic bleed, incidence of complications as placenta previa, abruptio placenta, development of gestational hypertension and pre eclampsia, intra uterine gro...

  8. The SMILE Program: Does Timing and Dosing of Nurse Home Visits Matter in Reducing Adverse Birth Outcomes for African American Women

    Science.gov (United States)

    2013-03-13

    aspiration, prenatal drug exposure, anemia , sickle cell trait, or identification of any other adverse health condition to include premature birth...p=.840), preeclampsia (LBW: χ 2 = .034, df= 1, p=.967; Premature: χ 2 =.087, df= 1, p=.920), placenta previa (LBW: χ 2 = .173, df= 1, p=.845...interdisciplinary approaches to research and practice (1st ed.). San Francisco, CA: Jossey-Bass. HOME VISITATION & BIRTH OUTCOMES 29 Fry-Johnson, Y . W

  9. Registros adicionales del carrao (Aramus guarauna en el estado de Jalisco, México

    Directory of Open Access Journals (Sweden)

    Carlos Palomera-García

    2015-06-01

    Full Text Available Se reportan registros adicionales del carrao (Aramus guarauna para el interior del Estado de Jalisco, México. Esta información, en conjunto con la previa conocida, apoya la idea que dice que la distribución de la especie podría está relacionada con la del caracol (Pomacea flagellata, Gastropoda: Ampullaridae que le sirve de alimento.

  10. Validación de los modelos de predicción de Framingham y PROCAM como estimadores del riesgo cardiovascular en una población colombiana

    Directory of Open Access Journals (Sweden)

    Oscar M. Muñoz

    2014-07-01

    Conclusiones: La función de riesgo de Framingham debería usarse con precaución en población colombiana de riesgo bajo e intermedio sin historia previa de eventos cardiovasculares dado que sobrestima el riesgo y tiene baja capacidad de discriminación. La función de riesgo de PROCAM ajustada por sexo es una mejor opción para estimar el riesgo de enfermedad cardiovascular dura.

  11. Escuela de la Espalda. Factores Predictivos.

    OpenAIRE

    Ibáñez Campos, Teresa

    2017-01-01

    Una gran parte de los padecimientos dolorosos de la columna lumbar tiene su origen, en un envejecimiento prematuro de sus discos y segmentos asociados. Este proceso se acelera en los países industrializados, debido a una serie de factores negativos que conlleva la vida moderna: esfuerzos grandes o pequeños repetitivos sin preparación previa, abuso de las posturas erectas o sedentarias, obesidad, escaso uso de la movilidad vertebral, flexión incorrecta y, otros fa...

  12. EN BUSCA DE LA PALABRA EXACTA. OBSERVACIÓN DEL PROCESO TRASLATIVO

    OpenAIRE

    Schäpers, Andrea

    2008-01-01

    El objeto del presente estudio observacional es describir las estrategias aplicadas por un grupo de estudiantes españoles para resolver problemas léxicos que se plantean cuando han de traducir un texto desde su lengua materna al alemán. Se trata de un estudio cualitativo motivado por la investigación previa sobre métodos introspectivos y retrospectivos empleados para describir los procesos cognitivos inherentes a la traducción ...

  13. Endocarditis por Streptococcus bovis: ¿sólo una endocarditis?

    OpenAIRE

    Angelini, Julieta María; Díaz Perera, Rodrigo; Garay, María Eugenia; Martínez, Camilo; Occhiuzzi, Silvina; Rodríguez Russo, Paula; Sarlo, Ana Julia

    2012-01-01

    Paciente varón de 74 años de edad, con antecedentes de cáncer de vejiga en plan de tratamiento quimioterápico, que ingresa al servicio de guardia por presentar fiebre de 38,5º astenia, adinamia e hiporexia asociado a disnea clase funcional II. Refiere al ingreso haber realizado la última sesión de quimioterapia una semana previa a la consulta.

  14. Contribución al estudio de los reacciones de hidratación del cemento portland por espectroscopia infrarroja II. Estudio de clínkeres y de cementos portland anhidros

    Directory of Open Access Journals (Sweden)

    Vázquez-Moreno, Tomás

    1976-06-01

    Full Text Available Not availableEn un artículo anterior (1 se dio cuenta de los trabajos realizados sobre la aplicación de la espectroscopia IR al estudio de las principales fases sintetizadas del clínker de cemento portland como fase previa al estudio de diversos clínkeres, obtenidos por nosotros en el laboratorio a partir de crudos industriales, y de distintos cementos portland comerciales anhidros.

  15. Singleton pregnancy outcomes after assisted and non-assisted reproductive technology in infertile patients.

    Science.gov (United States)

    Tsutsumi, Ryo; Fujimoto, Akihisa; Osuga, Yutaka; Ooi, Nagisa; Takemura, Yuri; Koizumi, Minako; Yano, Tetsu; Taketani, Yuji

    2012-07-01

    Singleton pregnancy after assisted reproductive technology (ART) has been associated with higher risks of adverse pregnancy outcome than naturally conceived singleton pregnancy. This study was to elucidate whether the ART procedure is responsible for abnormal pregnancy outcome comparing those after ART and non-ART in infertile patients. We compare the singleton pregnancy outcome of infertile patients in our university hospital between 2000 and 2008 following ART (351 pregnancies) and non-ART (213 pregnancies) procedures. Pregnancy outcome parameters were incidence of pregnancy induced hypertension, placenta previa, placental abruption, cesarean delivery, preterm birth, very preterm birth, stillbirth, low birth weight and very low birth weight. Most of the pregnancy outcome parameters were not significantly different between the ART group and the non-ART group. Only placenta previa was significantly higher in the ART group than in the non-ART group (odds ratio 4.0; 95 % CI 1.2-13.7). ART procedure may itself be a risk factor for the development of placenta previa. Some of the abnormal perinatal outcomes that had been previously attributed to ART, however, may be due to the baseline characteristics of infertile patients.

  16. Relationship between first trimester aneuploidy screening test serum analytes and placenta accreta.

    Science.gov (United States)

    Büke, Barış; Akkaya, Hatice; Demir, Sibel; Sağol, Sermet; Şimşek, Deniz; Başol, Güneş; Barutçuoğlu, Burcu

    2018-01-01

    The aim of this study is to determine whether there is a relationship between first trimester serum pregnancy-associated plasma protein A (PAPP-A) and free beta human chorionic gonadotropin (fβhCG) MoM values and placenta accreta in women who had placenta previa. A total of 88 patients with placenta previa who had first trimester aneuploidy screening test results were enrolled in the study. Nineteen of these patients were also diagnosed with placenta accreta. As probable markers of excessive placental invasion, serum PAPP-A and fβhCG MoM values were compared in two groups with and without placenta accreta. Patients with placenta accreta had higher statistically significant serum PAPP-A (1.20 versus 0.865, respectively, p = 0.045) and fβhCG MoM (1.42 versus 0.93, respectively, p = 0.042) values than patients without accreta. Higher first trimester serum PAPP-A and fβhCG MoM values seem to be associated with placenta accreta in women with placenta previa. Further studies are needed to use these promising additional tools for early detection of placenta accreta.

  17. El radón: ¿riesgo para la salud?

    Directory of Open Access Journals (Sweden)

    Juan Miguel Barros Dios

    2011-12-01

    Full Text Available El radón (Rn222 es un gas noble radiactivo que procede directamente del radio (Ra226 cuando este emite una partícula alfa (dos protones y dos neutrones o núcleo de helio, y que a su vez se transforma en otro elemento radiactivo (Po218 al desprenderse de otra partícula alfa. Desde hace varias décadas se conoce su efecto como factor de riesgo del cáncer primario pulmonar, primero en mineros del uranio y posteriormente en la población general expuesta al radón residencial en hogares construidos sobre suelos de rocas ricas en uranio (U238, elemento inicial de la cadena de degradación radiactiva de la que procede el radón. Áreas geológicamente constituidas por granitos o pizarras, como son las de gran parte de Galicia y todo el noroeste y oeste de la península ibérica, han sido catalogadas como de alto riesgo de exhalación de radón al interior de edificios y domicilios. En numerosos países de América y Europa existen desde hace varios lustros, políticas de prevención del cáncer pulmonar en aquellas zonas de riesgo basadas en programas de reducción de radón en los domicilios y edificios públicos. Desde finales de los años 80, la radiación alfa procedente del radón y sus descen- dientes de vida media corta han sido clasificados como agentes cancerígenos por la Internacional Agency of Research on Cancer (Lyon, 1988 y el Nacional Research Council (BEIR IV, 1988, constituyendo la segunda causa de cáncer pulmonar después del tabaco, y responsable del 10 al 15 % de todas las muertes por esa neoplasia. Estudios realizados en Galicia confirman esta evidencia, con riesgos de 2 a 3 en expuestos a concentraciones del gas en domicilios y la responsabilidad directa del 9% de todos los casos de cáncer pulmonar del área estudiada y una interacción radón/tabaco que multiplica por 45 el riesgo.

  18. History of the future; Historia del futuro

    Energy Technology Data Exchange (ETDEWEB)

    Manzini, Fabio [Centro de Investigacion en Energia (CIE) de la UNAM, Temixco, Morelos (Mexico)

    2010-07-01

    The desired future is to imagine a world energized by energy sources that do not infringe against our environmental heritage, because the environment is the determining factor in the equation of human sustainability: without environment there is neither society nor economy. In this document are mentioned the energy reserves in Mexico of uranium as a fuel for the Laguna Verde nuclear power plant, Veracruz; coal, oil and natural gas. It also mentions the renewable resources and existing energy scenarios in Mexico. [Spanish] El futuro deseado es imaginarnos un mundo energizado por fuentes de energia que no atenten en contra de nuestro patrimonio ambiental, porque el ambiente es el factor determinante en la ecuacion de la sustentabilidad humana; sin ambiente no existe ni sociedad ni economia. En este documento se mencionan las reservas energeticas en Mexico de uranio como combustible para la central nuclear Laguna Verde, Veracruz; de carbon, de petroleo y gas natural. Se mencionan tambien los recursos renovables existentes y los escenarios energeticos en Mexico.

  19. MODELACIÓN DE ELEMENTOS TRAZA EN EL HORIZONTE A DE SUELOS, PLANCHA 170 (VÉLEZ, DEPARTAMENTOS DE SANTANDER Y BOYACÁ

    Directory of Open Access Journals (Sweden)

    LUIS HERNÁN SÁNCHEZ

    2008-01-01

    Full Text Available En este estudio, se analizó la distribución espacial de varios metales potencialmente tóxicos o peligrosos (EPP en suelos de la plancha 170 (Vélez. Se empleó una metodología de muestreo de baja densidad y se tomaron muestras de suelos del horizonte A, que fueron analizadas para 48 elementos químicos, usando plasma acoplado a masas y activación neutrónica. Los primeros tres componentes representan el 88% de la variabilidad total de los datos, identificándose las siguientes asociaciones: CP1= V-Sb-Mo-Cr-Ni-Zn-Cu-U, la cual representa el 73% de la varianza, incluye el mayor número de elementos y puede estar relacionado con la presencia de lodolitas y areniscas ricas en uranio y otros metales. El segundo componente principal CP2 = Ni-Zn-Cu podría representar la presencia de depósitos con sulfuros y por último CP3 = Mo-V-Ni-Sb-Cr indicaría una asociación natural derivada de shales que acumulan estos metales. Aplicando técnicas geoestadísticas se generó el mapa krigeado para el primer componente principal (CP1.

  20. Caracterización de rellenos fisurales por desequilibrios isotópicos de series radiactivas naturales. El caso del batolito granítico de El Berrocal

    Directory of Open Access Journals (Sweden)

    Hernández Benítez, A.

    1993-08-01

    Full Text Available The isotopic ratios obtained for geological materials from the granitic batholith of El Berrocal show values very close to equilibrium, like in a geochemically closed system, for the fresh granitic rock. The fracture fillings studied present values with a disequilibrium between radionuclides. This is due to the existance in the system of mobilization/retention phenomena for these elements. The fracture fillings have been sequentially leached and the results show that Uranium is preferently bound to the adsorbed and iron-rich phases. Thorium, with a lower geochemical mobility, is related mainly to the residual or detritical phases.Las relaciones isotópicas obtenidas en materiales del batolito granítico de El Berrocal muestran valores cercanos al equilibrio propios de un sistema geoquímicamente estable para la roca granítica sin alterar, mientras que en los rellenos fisurales se observan desequilibrios isotópicos que indican fenómenos actuales de movilización/retención de estos radisótopos. Los rellenos se han sometido a una lixiviación secuencial donde se observa que el uranio está asociado preferentemente a las fases adsorbidas y ricas en oxi-hidróxidos de hierro, mientras que el torio se moviliza con mayor dificultad y está asociado a la fase residual del relleno.

  1. Spatial analysis techniques applied to uranium prospecting in Chihuahua State, Mexico

    Science.gov (United States)

    Hinojosa de la Garza, Octavio R.; Montero Cabrera, María Elena; Sanín, Luz H.; Reyes Cortés, Manuel; Martínez Meyer, Enrique

    2014-07-01

    To estimate the distribution of uranium minerals in Chihuahua, the advanced statistical model "Maximun Entropy Method" (MaxEnt) was applied. A distinguishing feature of this method is that it can fit more complex models in case of small datasets (x and y data), as is the location of uranium ores in the State of Chihuahua. For georeferencing uranium ores, a database from the United States Geological Survey and workgroup of experts in Mexico was used. The main contribution of this paper is the proposal of maximum entropy techniques to obtain the mineral's potential distribution. For this model were used 24 environmental layers like topography, gravimetry, climate (worldclim), soil properties and others that were useful to project the uranium's distribution across the study area. For the validation of the places predicted by the model, comparisons were done with other research of the Mexican Service of Geological Survey, with direct exploration of specific areas and by talks with former exploration workers of the enterprise "Uranio de Mexico". Results. New uranium areas predicted by the model were validated, finding some relationship between the model predictions and geological faults. Conclusions. Modeling by spatial analysis provides additional information to the energy and mineral resources sectors.

  2. Conflictos socioambientales en torno a la energía nuclear. Perspectivas desde la Investigación para la Paz

    Directory of Open Access Journals (Sweden)

    Luis Sánchez Vázquez

    2011-06-01

    Full Text Available En los últimos años se ha reactivado el debate sobre la energía nuclear. Esta opción ha reemergido amparada en la etiqueta de «energía limpia», por la no emisión de gases de efecto invernadero en su proceso productivo. Sin embargo, la incertidumbre sobre las fases de tratamiento necesarias para administrar con seguridad los residuos, incluyendo, en su caso, el reprocesado del combustible; los problemas ambientales derivados de la minería del uranio; e incluso los riesgos laborales derivados del trabajo con material fisionables, componen un panorama de situaciones conflictivas de carácter complejo que continúa siendo el principal caballo de batalla de la oposición antinuclear y ecologista. En este artículo se pretenden identificar los distintos conflictos socioambientales aparejados a la energía nuclear teniendo en cuenta su ciclo de vida completo, con el objetivo aportar soluciones al debate sobre la problemática ambiental en torno a la energía nuclear desde la perspectiva de la Investigación para la Paz.

  3. Asymptotic energies and sustainable electrical development; Energias asintoticas y desarrollo electrico sustentable

    Energy Technology Data Exchange (ETDEWEB)

    Velez O, Carlos [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2003-07-01

    A review is made of the energy resources in use existing at the moment for the electricity production (hydraulic, coal, oil, gas and uranium). The asymptotic energies (solar, geothermal and nuclear fission and fusion) are described and the state of development in which they are up to the moment. One concludes that in the case of Mexico it would be convenient to make flexible and to reinforce the electrical systems in forecast of a greater participation of the distributed generation and to orient the extensions of the electrical generation to make a greater use of the three asymptotic energies already used: the solar (in its forms hydraulic and wind power), geothermal and the nuclear fission. [Spanish] Se pasa revista a los recursos existentes en las energias actualmente en uso para la produccion de electricidad (hidraulica, carbon, petroleo, gas y uranio). Se describen las energias asintoticas (solar, geotermia y fision y fusion nucleares) y el estado de desarrollo en que se encuentran hasta el momento. Se concluye que en el caso de Mexico convendria flexibilizar y reforzar el sistema electrico en prevision de una mayor participacion de la generacion distribuida y orientar las ampliaciones de la generacion electrica para hacer un mayor uso de tres de las energias asintoticas ya utilizadas: la solar (en sus formas hidraulica y eolica), la geotermia y la fision nuclear.

  4. Assessing Kazakhstan´s Proposal to Host a Nuclear Fuel Bank

    Directory of Open Access Journals (Sweden)

    Caitlin A. Buckley

    2012-01-01

    Full Text Available Los defensores del control de armamentos buscan mecanismos para desincentivar la extensión de tecnologías sensibles para la proliferación. La mayoría de planes consideran situar las tecnologías del ciclo de combustible nuclear bajo un mayor control multilateral. Las propuestas para establecer uno o más bancos de combustible nuclear encajan claramente en este enfoque. Bajo este sistema, los países pueden "tomar prestado" el combustible que necesiten para sus reactores nucleares de un repositorio bajo control de la AIEA. Kazajstán ha ofrecido considerar el establecimiento de un banco internacional de combustible nuclear en su territorio. El país cuenta con ciertas características que podrían convertirlo en un buen candidato para un banco de combustible. Por ejemplo, Kazajstán es un actor destacado en el mercado internacional de uranio, tiene buenas relaciones con muchos países, y su gobierno cuenta con un historial sólido de no proliferación. Sin embargo, existe preocupación entre los observadores nacionales e internacionales acerca del ambicioso programa del gobierno kazajo, sus relaciones con países propensos a la proliferación, y la oposición de la sociedad en Kazajstán a las actividades nucleares.

  5. Diagnosis and suggestions for the knowledge management applied to a nuclear installation: the uranium hexafluoride production unit

    International Nuclear Information System (INIS)

    Marchesini, Paulo Roberto de Andrade

    2008-01-01

    It has been more than 25 years since Brazilian Navy started applying resources and staff in a nuclear power program in which the main objective is the necessary technology for project and construction of a nuclear power reactor and nuclear fuel production for naval propulsion. A long period project tends to be susceptible to loss of essential parcels of knowledge. The objective of the present research is to identify actions and initiatives that may improve learning and dissemination of knowledge in an organization that develops complexes projects during a long period of time. The revision of the literature about Knowledge Management allowed the researcher to select a reference that indicates how people involved in a project gets the necessary information and knowledge for developing their activities and uses them to add value and to learn how to contribute for the organization, in order to prevent nature difficulties. The adopted methodology was a case study on the implantation of the U nidade de Hexafluoreto de Uranio , which is being developed by the Centro Tecnologico da Marinha in Sao Paulo. With the application of structured and opened interviews, it was possible to identify some factors related with the attainment and dissemination of knowledge that can be developed. The result of this work was a proposal of action and initiatives that will improve the attainment of the knowledge, its structure and maintenance by the organization and the contribution by the people, of the knowledge acquired. (author)

  6. Uranium mining operations in Spain

    International Nuclear Information System (INIS)

    Rios, J.-M.; Arnaiz, J.; Criado, M.; Lopez, A.

    1995-01-01

    The Empresa Nacional del Uranio, SA (ENUSA) was founded in 1972 to undertake and develop the industrial and procurement activities of the nuclear fuel cycle in Spain. Within the organisation of ENUSA, the Uranium Division is directly responsible for the uranium mining and production operations that have been carried out since 1973 in the area of Ciudad Rodrigo in the province of Salamanca. These activities are based on open pit mining, heap leaching and a hydrometallurgical plant (Elefante) for extracting uranium concentrates from the ore. This plant was shut down in 1993 and a new plant was started up on the same site (Quercus) with a dynamic leaching process. The nominal capacity of the new plant is 950 t U 3 O 8 per year. Because of the historically low uranium prices which have recently prevailed, the plant is currently running at a strategic production rate of 300 t U 3 O 8 per year. From 1981 to 1990, in the area of La Haba (Badajoz province), ENUSA also operated a uranium production site, based on open pit mining, and an experimental extraction plant (Lobo-G). ENUSA is currently decommissioning these installations. This paper describes innovations and improvements that ENUSA has recently introduced in the field of uranium concentrates production with a view to cutting production costs, and to improving the decommissioning and site restoration processes in those sites where production is being shut down or resources have been worked out. (author)

  7. A Survey of the Fuel Cycles Operated in the United Kingdom; Etude d'ensemble sur les cycles de combustible au Royaume-Uni; Obzor toplivnykh tsiklov, ispol'zuemykh v soedinennom korolevstve; Estudio de los ciclos de combustible utilizados en el Reino Unido

    Energy Technology Data Exchange (ETDEWEB)

    Allday, C. [United Kingdom Atomic Energy Authority, Risley, Warrington, Lancs (United Kingdom)

    1963-10-15

    'un combustible au plutonium et ses incidences sur le prix de revient et le cycle du combustible. Enfin, il precise la place qu'occupent les reacteurs a l'uranium naturel gaine de magnox et les reacteurs AGR dans le programme britannique d'energie d'origine nucleaire. (author) [Spanish] a) El ciclo uranio natural/Magnox. En el Reino Unido se ha adoptado el reactor de uranio natural moderado con grafito y refrigerado con gas como base del respectivo programa de energia nucleoelectrica. Se explotan desde hace siete afios los reactores de Calder Hall y Chapelcross; ahora han comenzado a funcionar los reactores de Berkeley y Bradwell, de la Central Electricity Generating Board, y hay reactores en construccion o en proyecto en otros siete emplazamientos. El combustible destinado a esos reactores se prepara y elabora en el establecimiento de Springfields de la Atomic Energy Authority y de alli se transporta al reactor para efectuar la carga. Una vez irradiado y descargado, el combustible se lleva al establecimiento de la AEA en Windscale, para separar el uranio y el plutonio de los productos de fision. El autor resena la experiencia en el Reino Unido en materia de calculo y elaboracion de elementos combustibles, explotacion de reactores, transporte de combustible irradiado y regeneracion del mismo. Alude al comportamiento del combustible en un reactor y a los programas de carga y descarga alternada, tema que se desarrolla mas' extensamente en otra memoria. b) Reactores de combustible enriquecido. En el Reino Unido se viene probando un reactor avanzado refrigerado con gas, cuyo prototipo comenzo a desarrollar potencia en 1963. El combustible se elabora con oxido de uranio enriquecido revestido de acero inoxidable y sera regenerado en una seccion especial que se agregara al establecimiento de separacion de combustible Magnox en Windscale. El uranio enriquecido para el reactor avanzado (AGR) se produce en la planta de difusion gaseosa en Capenhurst. En lugar del oxido de uranio

  8. El comportamiento residencial de los mayores. Análisis biográfico de la movilidad en la vejez.

    Directory of Open Access Journals (Sweden)

    DOLORES PUGA

    2004-01-01

    Full Text Available En las actuales sociedades europeas envejecidas, los comportamientos residenciales de las personas de edad están adquiriendo una importancia creciente. En este artículo se exploran las relaciones causales entre la biografía migratoria previa y las pautas residenciales adoptadas tras los 55 años, usando Event History Analysis. Los resultados demuestran que el lugar de nacimiento marca la trayectoria migratoria posterior de los individuos, llegando a afectar incluso al comportamiento residencial en la vejez. La existencia de migraciones previas, el hábitat de residencia, así como la duración del período sedentario, ejercen también una importante influencia sobre la decisión de movilidad en la vejez. Finalmente, se demuestra que la reducción de la movilidad entre las generaciones de mayores más recientes es un efecto de su biografía migratoria previa. Las trayectorias migratorias protagonizadas por los individuos a lo largo de su vida, joven y adulta, se revelan más decisivas respecto a los comportamientos residenciales en la vejez que las circunstancias coyunturales. Por ello, posibles cambios en las biografías migratorias de las generaciones más jóvenes podrían traducirse en cambios en los niveles de movilidad en la vejez, independientemente de las circunstancias coyunturales. A este respecto se pueden observar diferencias por género, mostrándose las mujeres más vulnerables frente a las circunstancias históricas que los hombres.

  9. Preimplantation genetic diagnosis: a national multicenter obstetric and neonatal follow-up study.

    Science.gov (United States)

    Bay, Bjorn; Ingerslev, Hans Jakob; Lemmen, Josephine Gabriela; Degn, Birte; Rasmussen, Iben Anne; Kesmodel, Ulrik Schiøler

    2016-11-01

    To study whether women conceiving after preimplantation genetic diagnosis (PGD) and their children have greater risks of adverse pregnancy and birth outcomes compared with children conceived spontaneously or after IVF with or without intracytoplasmic sperm injection (ICSI). Historical cohort study. Not applicable. All deliveries following PGD treatment for single gene and sex-linked disorders or structural chromosomal aberrations (n = 126 deliveries/149 children), IVF/ICSI treatment (n = 30,418 deliveries/36,115 children), and spontaneous conception (n = 896,448 deliveries/909,624 children). None. Adverse obstetric and neonatal outcomes, such as pre-eclampsia, preterm primary rupture of membranes, placenta previa, abruption of placenta, preterm birth, low birth weight, malformations, and neonatal admission. Compared with spontaneously conceived pregnancies, PGD pregnancies were at significantly increased risk of placenta previa (adjusted odds ratio [ORa] 9.1; 95% confidence interval [95% CI] 3.4, 24.9), cesarean section (ORa 2.0; 95% CI 1.3, 2.9), preterm birth (ORa 1.6; 95% CI 1.0, 2.7), shorter gestation (mean difference -3.4 days; 95% CI -5.7, -1.1 days), and longer neonatal admission (mean difference 21 days; 95% CI 15, 28 days). The risks were comparable to that of pregnancies following IVF/ICSI. In subanalyses, adverse outcomes were only present in children conceived by PGD owing to parental monogenetic disorder and comparable to those of children born to parents with monogenic disorders conceiving without PGD, except for a higher risk of placenta previa. In this cohort study, the risk of adverse obstetric and neonatal outcomes was mainly related to the underlying parental condition rather than the PGD procedure. Copyright © 2016 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  10. Cervical Length in Patients at Risk for Placenta Accreta.

    Science.gov (United States)

    Rac, Martha W F; McIntire, Donald D; Wells, C Edward; Moschos, Elysia; Twickler, Diane D

    2017-07-01

    To evaluate cervical length measurements in women with placenta accreta compared to women with a nonadherent low-lying placenta or placenta previa and evaluate this relationship in terms of vaginal bleeding, preterm labor, and preterm birth. We conducted a retrospective cohort study between 1997 and 2011 of gravidas with more than 1 prior cesarean delivery who had a transvaginal ultrasound examination between 24 and 34 weeks for a low-lying placenta or placenta previa. Cervical length was measured from archived images in accordance with national guidelines by a single investigator, who was blinded to outcomes and ultrasound reports. The diagnosis of placental accreta was based on histologic confirmation. For study purposes, preterm birth was defined as less than 36 weeks, and cervical lengths of 3 cm or less were considered short. Standard statistical analyses were used. A total of 125 patients met inclusion criteria. The cohort was divided into patients with (n = 43 [34%]) and without (n = 82 [66%]) placenta accreta and stratified by gestational age at the ultrasound examinations. Women with placenta accreta had shorter cervical length measurements during their 32- to 34-week ultrasound examinations (mean ± SD, 3.23 ± 0.98 versus 3.95 ± 1.0 cm; P accreta had shorter cervical lengths at 32 to 34 weeks than women with a nonadherent low-lying placenta or placenta previa, but this finding did not correlate with a higher risk of vaginal bleeding or preterm labor resulting in preterm birth before 36 weeks. © 2017 by the American Institute of Ultrasound in Medicine.

  11. Viajando a la Tierra del Pasado. (pág. 19-33

    Directory of Open Access Journals (Sweden)

    David Esteban Lastra Romero

    2009-12-01

    Full Text Available Este documento presenta el diseño y la ejecución de una actividad educativa producto de un proceso de contextualización e indagación de ideas previas realizado en el IED Campestre Monte Verde en el curso 502. La actividad está centrada en el cuento como estrategia para el desarrollo de contenidos referentes al registro fósil como evidencia de la evolución y el cambio de los seres vivos a través del tiempo. En el diseño de la actividad y el cuento se asume la propuesta de Egan (1999 en la cual es fundamental presentar dentro de la historia conceptos que sean pares opuestos y que se relacionen  directamente con el tema que se desea enseñar. Estos pares opuestos buscan que los estudiantes encuentren situaciones complejas desde el punto de vista afectivo de tal manera que se genere un conflicto entre las ideas previas y los conceptos a enseñar.  El trabajo con los pares opuestos seleccionados en el diseño del cuento, facilitó la comprensión de fenómenos como la supervivencia y el cambio de los seres vivos desde la dimensión afectiva y el conflicto entre las ideas previas y los conceptos trabajados. No obstante, para evidenciar resultados en cuanto a actitudes y comportamientos que reflejen la utilidad del conocimiento adquirido, se requiere de un periodo de trabajo más prolongado.

  12. Variantes del concepto de renta en los países miembros de la CAN

    OpenAIRE

    Chuquimarca Chuquimarca, Jorge Luis

    2013-01-01

    El concepto de renta ha presentado en todo momento de la historia tributaria un análisis variado no sólo producto del Derecho, sino a su entendimiento han concurrido diversas ciencias, como actores; en las primeras constan la Economía, Finanzas Públicas, Contabilidad; y en los segundos doctrinarios, juristas, empíricos e incluso personas sin experiencia previa en la materia. El Impuesto a la Renta, corazón de un sistema tributario, impuesto dominante de los restantes tributo...

  13. Cuatrocientos setenta y siete casos de uretritis masculina

    Directory of Open Access Journals (Sweden)

    Federico Díaz González

    1985-12-01

    Full Text Available En el año de 1985 se estudiaron, desde el punto de vista del laboratorio, 477 casos de uretritis masculina; 49 de ellos (10.3% fueron de uretritis gonocócica (UG y 428 (89.7% de uretritis no gonocócica (UNG. Estos resultados concuerdan con los obtenidos en series previas; se discute la importancia de la UNG y se plantea la posibilidad de que muchos de los casos de esta entidad sean de la modalidad postgonocócica (UPG.

  14. El impacto del Plan Colombia a la asistencia internacional en Carchi, Sucumbíos y Esmeraldas 1998-2001

    OpenAIRE

    Guzmán León, Alicia

    2003-01-01

    La presente tesis tiene como propósito principal plantear las tendencias de asistencia internacional registradas en las provincias del norte previa la aplicación del Plan Colombia y posterior a la misma. El objetivo central de esta investigación es determinar cómo está conformada la asistencia en estas tres provincias, quiénes son los donantes, agencias ejecutoras e instituciones beneficiarias para establecer las dinámicas que se generan a partir del Plan Colombia en esta zona ...

  15. Análisis estadístico del control de calidad en las empresas

    OpenAIRE

    Galicia Andrés, Eduardo

    2013-01-01

    La aplicación de la estadística en la verificación del cumplimiento de determinadas exigencias de calidad en la industria está basada en el estudio y evaluación de la variabilidad, materia objeto de la Estadística. En el presente proyecto de fin de carrera en el que se van a aplicar 2 herramientas muy útiles para un amplio sector empresarial, como son el muestreo de aceptación y el control del proceso de fabricación, se exponen, de forma previa, algunos conceptos teóricos en...

  16. Efectividad del Caldo Lactosado con Azul de Bromotimol en el control bacteriológico de las desinfecciones profilácticas en instalaciones bovinas

    OpenAIRE

    Cepero Rodríguez, Omelio:; Silveira Prado, Enrique A.:; Suárez Fernández, Yolanda E.:; González García, Oraida:

    2008-01-01

    Con la finalidad de evaluar la efectividad del medio de cultivo CaldoLactosado con Azul de Bromotimol (CLAB) en el control bacteriológico de las desinfecciones profilácticas se realizó un estudio en unidades bovinas cuyos resultados se compararon en paralelo con los obtenidos con el medio de Heifetz Modificado (HM), establecido en Cuba para esta actividad. Previa limpieza mecánica se aplicaron las soluciones desinfectantes mediante una unidad móvil y después de tres horas de exposición se rea...

  17. Estudo fitoqu?mico e biol?gico de guatteria citriodora ducke

    OpenAIRE

    Rabelo, Diego de Moura

    2008-01-01

    A Guatteria citriodora Ducke ? uma esp?cie amaz?nica da fam?lia Annonaceae, conhecida popularmente como envira-amarela ou laranjinha, a qual ocorre em floresta pluvial de terra firme com distribui??o nos estados do Amazonas e Par?, bem como nas Guianas, Suriname, Bol?via, Equador, Col?mbia, Peru e Venezuela. O estudo fitoqu?mico da casca do caule dessa planta resultou no isolamento de tr?s alcal?ides oxoaporf?nicos, O-metilmoshatolina, liriodenina e oxoputerina, essas subst?ncias foram previa...

  18. Cuando los mundos chocan

    Directory of Open Access Journals (Sweden)

    García-Borrás, F.J.

    2006-04-01

    Full Text Available Desde una perspectiva netamente didáctica, en este artículo se pretende analizar las posibilidades e incidencias que la ciencia-ficción2 puede tener en el aula. El período de la adolescencia encuentra en la ciencia-ficción una forma de explicar sus necesidades y sus ideas previas. Por tanto, para facilitar sus procesos de aprendizaje, al mismo tiempo que los profesores pueden ver enriquecida su metodología de enseñanza, se muestran diversas fórmulas de acercamiento al alumno por medio de un motivador entorno de aprendizaje.

  19. Métodos de búsqueda y resultados en países en desarrollo: el caso de Venezuela

    OpenAIRE

    Gustavo Márquez; Cristobal Ruiz-Tagle

    2004-01-01

    (Disponible en idioma inglés únicamente) En este trabajo se emplean datos de panel de Venezuela recabados recientemente correspondientes al período de 1994 a 2002 para analizar tres cuestiones básicas: la primera tiene que ver con la influencia de las características individuales y la experiencia previa en el mercado laboral en la elección de métodos de búsqueda distintos. La segunda se refiere a la eficacia de diversos métodos de búsqueda para salir del desempleo y se controlan las caracterí...

  20. Parto vaginal tras cesárea

    OpenAIRE

    San Martín Bragado, María

    2016-01-01

    Cuando una mujer ha sido sometida a una cesárea previa existen dos opciones para ella en el caso de que se quede embarazada: repetir cesárea o intentar un parto vaginal. A pesar de los riesgos, el parto vaginal después de una cesárea es una situación atractiva para muchas pacientes y dará lugar a un resultado exitoso en un alto porcentaje de casos. Se ha de tener en cuenta que la realización de una cesárea electiva no está exenta de riesgos Grado en Medicina

  1. La dimension etica de la gestion de compra: un caso venezolano en el sector petrolero

    OpenAIRE

    Abreu, J. L.

    2004-01-01

    El trabajo de investigación tuvo como objetivo determinar la relación que existe entre los elementos de la gestión de compra y los factores éticos involucrados, previa identificación de estos elementos y factores. Se efectuó un tipo de investigación de carácter descriptivo. La población estuvo conformada por compradores de 46 empresas constructorascontratistas que prestan servicio a Petróleos de Venezuela en la Costa Oriental del Lago de Maracaibo, Venezuela. El diseño de la investigación fue...

  2. Inteligencia emocional como alternativa para la prevención del maltrato psicológico en la pareja

    OpenAIRE

    Blázquez Alonso, Macarena; Moreno Manso, Juan Manuel; García-Baamonde Sánchez, Mª Elena

    2009-01-01

    El artículo destaca la necesidad del empleo de la inteligencia emocional como una alternativa constructiva para la prevención del mal-trato psicológico en la pareja. Basándonos en las investigaciones que afir-man que habitualmente las manifestaciones de maltrato psicológico en la pareja son previas a las físicas (Follingstad, Rutledge, Berg, Hause y Polek, 1990; Loring, 1994; O´Leary, 1999) y que el impacto en las víctimas es igual o superior al ocasionado por el maltrato fisico (Henning y Kl...

  3. El idealismo en la filosofía medieval: el caso de Juan Escoto Eriúgena

    OpenAIRE

    Moran, Dermont

    2012-01-01

    Quiero sostener en este artículo (en contra de la posición de Myles Burnyeat) que el idealismo es una posibilidad filosófica genuina previa a Descartes. En efecto, podemos encontrar una versión del idealismo que supone un concepto desarrollado de subjetividad en una sofisticada versión del  Periphyseon de Escoto Eriúgena. El inmaterialismo intelectualista extremo de Eriúgena difiere del idealismo moderno en la medida en que aquél no está motivado tanto por una consideración epistemológica de ...

  4. Masonería y Sociabilidad en el centro y sur de la campaña bonaerense: Fines del siglo XIX principios del XX

    OpenAIRE

    Yolanda de Paz Trueba

    2011-01-01

    El objetivo de este trabajo es reflexionar en torno a la relación establecida entre la sociabilidad política derivada de la influencia masónica y otras formas de sociabilidad previas ligadas al catolicismo, en el marco de la construcción del Estado en sus diversos niveles a fines del siglo XIX. Este abordaje será realizado a través del análisis de pueblos de la campaña bonaerense, espacios no estudiados en este sentido hasta el momento.

  5. Los nuevos productos y las marcas olfativas

    OpenAIRE

    Hernández Alfaro, Mati

    2008-01-01

    I. Consideraciones previas. II. La aptitud de los olores para distinguir productos o servicios en el mercado. III. Clasificación de los productos de acuerdo con la función que cumple el aroma que incorporan. IV. El carácter genérico, habitual o funcional de algunos signos olfativos. V. La definición de marca y el reconocimiento de la posibilidad de emplear signos olfativos como marcas. VI. El uso de signos atípicos como marcas y el principio de publicidad registral: VI.1. ...

  6. Prevalencia del consumo de medicamentos en la población adulta de Cataluña

    OpenAIRE

    Sans S.; Paluzie G.; Puig T.; Balañá L.; Balaguer-Vintró I.

    2002-01-01

    Objetivos: Describir la prevalencia de la utilización de medicamentos según factores sociodemográficos y estado de salud autopercibido en la población adulta. Métodos: Examen de salud transversal del estudio CRONICAT/MONICA-Cataluña realizado en 1994-1996 en una muestra aleatoria de la población general de 25 a 64 años. Se interrogó a 3.421 participantes (tasa de respuesta del 72%) con cuestionario abierto sobre los medicamentos consumidos durante las dos semanas previas y otros hábitos de sa...

  7. La filosofía práctica y el método dialéctico aristotélicos: ¿Es la argumentación práctica una especie de dialéctica?

    OpenAIRE

    Bieda, Esteban

    2012-01-01

    Es sabido que Aristóteles suele comenzar la mayor parte de sus investigaciones con un relevamiento de posiciones y/o concepciones previas relativas al tema a tratar. En el presente trabajo trataremos de mostrar que tanto las referencias a autores anteriores como a las opiniones corrientes sobre el tema tratado responden a las exigencias de cierto proceder metódico que las necesita como elementos constitutivos. Nuestra tarea concreta consistirá en intentar develar el valor metódicoepistemológi...

  8. El georrádar como técnica de diagnóstico de presas mineras abandonadas. El distrito de Linares (Jaén, España)

    OpenAIRE

    Martínez, Julián; Rey Arrans, Javier; Hidalgo Estévez, Mari Carmen; Luque Espinar, Juan Antonio

    2013-01-01

    En Linares (Jaén) existió una gran actividad minera asociada a un cortejo filoniano de sulfuros metálicos. Estas antiguas labores mineras generaron grandes volúmenes de residuos acumulados sin ningún tipo de actuación correctora previa. En este trabajo se han seleccionado dos presas mineras de finos de lavadero (La Cañada I y La Mejor 1ª-2ª). La caracterización interna de estas estructuras se ha realizado mediante técnicas de prospección electromagnética, en concreto, con ge...

  9. Economic impact of infectious Laryngotracheitis in a commercial layer farm in Lima, Peru

    OpenAIRE

    Alvarado E, Jessica; Icochea D, Eliana; Reyna S, Pablo; Angulo J, Carlos; Zegarra V, Raúl

    2013-01-01

    El objetivo del estudio fue evaluar el impacto económico causado por la laringotraqueitis infecciosa aviar (LT) en una granja de ponedoras comerciales, ubicada en el distrito de Chilca, Lima, con una población de 14 415 gallinas, que fue afectada por la LT entre agosto de 2008 hasta marzo de 2009. Se elaboró una encuesta y se recolectaron datos sobre bioseguridad, producción y costos de producción del lote afectado con LT así como de la campaña previa sin LT. El impacto económico causado por ...

  10. Políticas de buenas prácticas relacionadas con la seguridad informática y la continuidad del negocio en el mall del centro

    OpenAIRE

    Erazo Parra, José Luis

    2016-01-01

    Al realizar una búsqueda en la biblioteca de UNIANDES, se encontró un trabajo, que sirve como antecedente al presente trabajo investigativo, al que destaco el trabajo realizado por la Master, Viera Zambrano, con su tema” Plan administrativo de red interna para mejorar la seguridad de la información de la Escuela de perfeccionamiento de aerotécnicos de la Fuerza Aérea”, trabajo presentado en el año 2015, previa a la obtención del título de Magister en Informática Empresarial. ...

  11. Juegos matemáticos en Educación Infantil

    OpenAIRE

    Pino de Ávila, Concepción

    2013-01-01

    Los niños, desde edades muy tempranas se encuentran en contacto permanente con las matemáticas. Las metodologías de enseñanza educativa deben regular estas experiencias previas que los niños traen convirtiéndolas en aprendizajes significativos para ellos, pero gradualmente, de manera que los niños puedan identificar, nominar y representar los números, así como identificar los demás contenidos matemáticos, es decir, las formas, tamaños, medidas y colores reconociéndolos por sus ...

  12. Prevalencia de deshidratación en futbolistas profesionales chilenos antes del entrenamiento

    OpenAIRE

    Castro-Sepúlveda, Mauricio; Astudillo, Sebastián; Álvarez, Cristian; Zapata-Lamana, Rafael; Zbinden-Foncea, Hermann; Ramírez-Campillo, Rodrigo; Jorquera, Carlos

    2015-01-01

    Introducción: existen pocos estudios relacionados con el estado de hidratación pre-entrenamiento en futbolistas profesionales. Objetivo: determinar la prevalencia de deshidratación pre-entrenamiento en jugadores profesionales de fútbol. Metodos: se incluyeron un total de 156 jugadores de fútbol (edad 25,4 ± 5,2 años) de seis clubes profesionales chilenos. No se hicieron recomendaciones previas de hidratación ni de ingesta de alimentos, con el objetivo de evaluar el estado de hidratación bajo ...

  13. La experiencia de las enfermeras ante la muerte

    OpenAIRE

    Alvarez de Arriba, Daniel

    2016-01-01

    Trabajo fin de grado en Enfermería Introducción: Las enfermeras han heredado de la sociedad un concepto histórico de la muerte que en la actualidad se ha convertido en tabú. Esto produce sentimientos negativos cuando enfrentan la muerte de sus pacientes en la práctica diaria. Esta experiencia es común a todas las enfermeras y se encuentra influenciada por diversos factores: la experiencia laboral, unidad de trabajo, creencias religiosas, educación previa y edad del fallecido. Objetivo: ...

  14. Generalization in chess thinking

    OpenAIRE

    D'Eredit??, Giuliano; Ferro, Mario

    2015-01-01

    En este trabajo abordamos la generalizaci??n en el pensamiento en el juego del ajedrez. La generalizaci??n es un complejo proceso basado en informaci??n adquirida durante experiencias previas. En el campo del ajedrez, los libros de ajedrez, la educaci??n en el ajedrez y la pr??ctica personal con el juego aportan la informaci??n que posibilita la generalizaci??n. La forma en que la generalizaci??n se produce en el ajedrez es todav??a un tema que merece m??s investigaci??n. En este art??culo...

  15. Contaminación aguda por vertidos textiles: Tratamiento de carpines dorados (Carassius auratus) con dicromato potásico; determinación de la toxicidad y niveles de cromo en branquias.

    OpenAIRE

    Riva Juan, María del Carmen; Flos Bassols, Rosa; Crespi Rosell, Martí; Balash, J.

    1980-01-01

    El cromo es el metal pesado cuantitativamente más importante en el vertido de la Industria Textil; procede esencialmente de los procesos de tintura con colorantes cromatables. Hemos sometido carpines dorados al tratamiento agudo con dicromato potásico disuelto en el agua de tanques experimentales. Se determina la toxicidad y los niveles de cromo en branquias. La concentración de cromo en el tejido branquia1 se halla mediante espectrofotometría de absorción atómica, previa digestión c...

  16. Lecciones y desafíos para la transición hacia la paz. Reporte ejecutivo

    OpenAIRE

    Giraldo Ramírez, Jorge; Leyva, Santiago; Mejía Arango, Juan Luis

    2015-01-01

    El seminario internacional “Retos y desafíos de la transición hacia la paz” realizado en Medellín por la alianza constituida por Proantioquia, Fescol y la Universidad EAFIT entre el 16 y el 17 de abril de 2015, se propuso discutir aprendizajes y retos de experiencias previas que puedan contribuir a que la transición de la guerra a la paz en el país siente las bases de un postconflicto pacífico y sostenible. El presente documento sintetiza las reflexiones suscitadas en el marco del seminario. ...

  17. Materiales cementicios de baja energía : Activación térmica de arcillas, relación entre estructura y actividad puzolánica

    OpenAIRE

    Tironi, Alejandra

    2013-01-01

    El objetivo general de la presente tesis es estudiar la relación entre la composición mineralógica y estructural de diferentes arcillas argentinas, el proceso de calcinación y la actividad puzolánica cuando se las utiliza como reemplazo parcial del cemento; con el fin de desarrollar materiales cementicios de baja energía y aceptables propiedades ingenieriles. Sus objetivos específicos: Seleccionar arcillas para su potencial uso como material puzolánico, previa activación ...

  18. La cirugía periapical de los molares

    OpenAIRE

    Gay Escoda, Cosme; Paredes García, Jordi; Berini Aytés, Leonardo

    1993-01-01

    Se han estudiado 65 pacientes sometidos a intervención quirúrgica periapical en 72 molares ( 120 raíces y 155 conductos radiculares). Se analizó una serie de características preoperatorias (edad, antecedentes patológicos, patologías asociadas, distribución de dientes afectados, tamaño de la lesión periapical, tipo de endodoncia ortógrafa y calidad radiológica de la endodoncia previa), peroperatorias (tipo de incisión, existencia de comunicación oroantral, afectación cortical, tamaño de la res...

  19. Estructura atómica : análisis y estudio de las ideas de los estudiantes (8º de EGB)

    OpenAIRE

    Fuente, Ana María de la; Perrotta, María Teresa; Dima, Gilda; Gutiérrez, Elena; Capuano, Vicente; Follari, Beatriz

    2003-01-01

    Este trabajo se propone indagar las ideas de los estudiantes del tercer ciclo de la educación general básica (EGB) en la República Argentina, jóvenes de 12 a 14 años, con el propósito de conocer lo que piensan sobre la estructura atómica. Utilizando una metodología cuantitativa, se implementó una encuesta que se llevó a cabo con 78 alumnos. El cuestionario utilizado, validado en dos oportunidades, fue elaborado por los autores de este trabajo, tomando resultados de entrevistas previas llevada...

  20. Análisis económico financiero para el traslado de personal operativo hacia una empresa outsourcing o hacia un servicio técnico inhouse

    OpenAIRE

    González Orellana, Humberto Javier

    2008-01-01

    La presente tesis previa a la obtención del título de Master en Dirección de Empresas tiene como objetivo principal el analizar dos posibles modelos a ser implementados en la unidad de negocios NESCAFE® de la empresa NESTLE ECUADOR S.A. con el fin de disminuir los costos operativos que impactaron drásticamente en el estado de pérdidas y ganancias de 2006. Para lograr esto, como primera instancia se describirá el modelo actual con el que viene trabajando la unidad NESACFE® en el Ecuador. Pa...

  1. Factores predictores del consumo de tabaco entre adolescentes del Colegio Universitario Santiago de Cali, 2005

    OpenAIRE

    Yamileth Ortiz-Gómez; Jorge Martín Rodríguez-Hernández

    2009-01-01

    Objetivos: Identificar los factores predictores del consumo de tabaco entre los adolescentes del Colegio Santiago de Cali. Materiales y métodos: Estudio transversal con una muestra de 286 adolescentes matriculados y activos de grado 6 a 9 en el año lectivo 2005. A partir de la prevalencia del consumo de tabaco, se estimaron diferencias para las variables independientes con Ji2 y valores P. Los factores predictores fueron establecidos con un modelo logístico no condicional, previa evaluación d...

  2. Relación entre Estilos de Liderazgo y Clima Organizacional en una Empresa de Servicios de Topografía en Arequipa, 2014

    OpenAIRE

    Araujo Chávez, Susan Analí

    2017-01-01

    RESUMEN Esta investigación titula “Relación entre estilos de liderazgo y clima organizacional en un empresa de servicios de topografía en Arequipa 2014”, el objetivo es determinar la relación que existe entre estilos de liderazgo y clima organizacional. Previa revisión de la literatura afín existente, se conjeturó que los estilos de liderazgo tienen relación significativa con el clima organizacional de la empresa en estudio. La presente investigación nace de la propia sensibilidad de la a...

  3. Diseño de un sistema de control interno administrativo financiero para los departamentos.....

    OpenAIRE

    Paz Novoa, Lorena María

    2012-01-01

    RESUMEN Resumen Ejecutivo de la Tesis previa a la obtención del título de: INGENIERA COMERCIAL CON MENCIÓN EN CONTABILIDAD Y AUDITORÍA Para que sea esto posible se realizó una propuesta de Control Interno que cuenta con un grupo de políticas de control para los departamentos analizados, procedimientos y actividades que la compañía tendrá a su disposición para realizar una posterior implementación El trabajo consta de cinco capítulos, en lo que se encuentran contenidos todos ...

  4. Centralidad, valores y ética protestante del trabajo en población urbana ocupada Centrality, values and protestant work ethic in employed urban population

    OpenAIRE

    Graciela Filippi; Elena Zubieta; Valeria Calvo; M. Laura Napoli; Samantha Ceballos; Yamila Iun Ferrero; Maite Beramendi; Paula Furlano; Esteban Cordoba

    2007-01-01

    Desde una perspectiva psicosocial que ahonda en la dimensión subjetiva de la cultura se indaga en creencias y valores asociadas al trabajo. A partir de investigaciones previas y los presupuestos de la teoría de los valores, la centralidad del trabajo y la ética protestante del trabajo, se ha realizado un estudio empírico de naturaleza exploratoria descriptiva. El objetivo general de la investigación marco es explorar en diferentes muestras urbanas aspectos psicosociales relacionados con el tr...

  5. Dificultades de los menores en protección ante la superación de etapas escolares y la emancipación

    OpenAIRE

    Xosé Manuel Cid; Deibe Simo

    2014-01-01

    En el trabajo educativo diario con jóvenes en riesgo observamos como frecuentemente se repite una historia de fracaso escolar que repercute intensamente cuando se inicia el proceso de tránsito a la vida adulta. La escuela reproduce situaciones de exclusión y contribuye con su rigidez académica a alejar a adolescentes que en su etapa previa a la emancipación, cuentan con  pretensiones y necesidades principalmente prácticas. Las experiencias negativas vinculadas al sistema educativo se suman a ...

  6. Determinación de la evaluación del desempeño en Estadística Aplicada con análisis ROC

    OpenAIRE

    Oliver Germes, Amparo; Vivo, Juana-María; Galiana, Laura; Sancho, Patricia

    2013-01-01

    Las dificultades en la enseñanza y el aprendizaje de la estadística han sido objeto de interés de los investigadores. Muchos estudios han intentado describir los factores que influyen en los resultados de la asignatura estadística. El objetivo de esta investigación es doble: a) evaluar los efectos de asistir presencialmente a las clases de estadística, del interés por la asignatura, del feedback colectivo, de la satisfacción y de la experiencia previa sobre el rendimiento en asignaturas de es...

  7. Masonería y Sociabilidad en el centro y sur de la campaña bonaerense: Fines del siglo XIX principios del XX

    Directory of Open Access Journals (Sweden)

    Yolanda de Paz Trueba

    2011-12-01

    Full Text Available El objetivo de este trabajo es reflexionar en torno a la relación establecida entre la sociabilidad política derivada de la influencia masónica y otras formas de sociabilidad previas ligadas al catolicismo, en el marco de la construcción del Estado en sus diversos niveles a fines del siglo XIX. Este abordaje será realizado a través del análisis de pueblos de la campaña bonaerense, espacios no estudiados en este sentido hasta el momento.

  8. Sonographic monitoring of complications and anomalies in twin gestations

    International Nuclear Information System (INIS)

    Coleman, B.G.; Grumbach, K.; Arger, P.H.; Mintz, M.C.; Arenson, R.L.; Mennuti, M.T.; Gabbe, S.G.

    1986-01-01

    One hundred sixty-eight twin gestations were evaluated to assess the role of US in the diagnosis of obstetric complications and anomalies. US revealed the following complications: symptomatic polyhydramnios (eight cases), myomas (seven), placenta previa (three), and abruption (five). Fetal anomalies included twin-twin transfusion syndrome (two), acardiac anomaly (two), chromosomal abnormality (two), anencephaly (one), hydrocephaly (one), and conjoined twins (two). In 26 gestations intrauterine fetal demise or neonatal death involved one or both twins for a total of 42 deaths, constituting a mortality of 12.5%. No maternal deaths occurred. The impact of sonographic monitoring on the obstetric management of twin gestations is emphasized

  9. Neuromitos de los profesores chilenos: orígenes y predictores

    OpenAIRE

    Varas-Genestier, Paulina; Ferreira, Roberto A

    2017-01-01

    El presente estudio investigó la prevalencia de neuromitos y el conocimiento general de neurociencia de profesores chilenos. Se encuestó a 91 profesores de enseñanza básica y media de diferentes establecimientos. En línea con las investigaciones previas, los resultados demostraron que los profesores poseen cierto conocimiento general de neurociencia, pero también tienen muchas concepciones erróneas o neuromitos como los referentes a las metodologías VAK, Brain Gym® y la dominancia hemisférica...

  10. Fabricación de nanopartículas metálicas por métodos físicos con tamaño, composición química y estructura contraolados. Nanopartículas de Co, Au, Ag, aleación Ag-Au y Ag-Au-Pd, y Ag@Au

    OpenAIRE

    Ruano Díaz, Manuel

    2013-01-01

    La técnica de fabricación de nanopartículas ICS utilizada ha demostrado ser capaz de generar nanopartículas de alta pureza con gran precisión, pero presenta una principal limitación: el uso de un único blanco. Esta condición de trabajo impide la generación de nanopartículas heteroestructuradas, formadas por varios elementos distintos, controlando la composición química. Nuestra experiencia previa con la ICS estándar motiva que nuestro grupo de investigación desarrolle una versión mejorada de ...

  11. Supuestos ontológicos, epistemológicos y éticos que subyacen a la disciplina contabilidad y ubicación de la misma dentro de la tecnofilosofía

    OpenAIRE

    Piacquadio, Cecilia; Centro de Investigaciones en Auditoría y Responsabilidad Social

    2011-01-01

    La contabilidad entendida en sentido amplio es una tecnología que se nutre de diversas ciencias y, en ocasiones, aún del resultado de previas investigaciones contables, constituyendo las modelizaciones contables el principal artefacto de esta sociotecnología. Asimismo, nos apartamos de la tajante divergencia empirista hechos-marco teórico y asumimos que el mundo de los hechos-sociales, en este caso- dista de ser independiente del marco teórico empleado por el tecnólogo social para su estudio....

  12. Estudio de prevención de riesgos laborales para una obra de edificación en fase de estructuras

    OpenAIRE

    Romero López, Xavier

    2011-01-01

    La realización de este proyecto sintetizará y agrupará los riesgos laborales de cada tipo de estructura citadas para este estudio, estructura de hormigón armado, metálica y de madera. En base a esto se propondrán una serie de medidas adecuadas, ya sean de protección colectiva y/o individual o medidas de prevención. El estudio de los diferentes tipos de estructuras abarca una investigación previa de los diferentes tipos de trabajos, donde se analizan minuciosamente las act...

  13. Estudio de factibilidad financiera y económica para la creación de una planta productora de eco fundas basadas en el bioplástico en el cantón Cuenca

    OpenAIRE

    Loja Sarmiento, David Esteban; Muñoz Coronel, Willian Andrés

    2013-01-01

    Previa la instalación de cualquier tipo de empresa, negocio u organismo se gubernamental, privado o mixto, unipersonal o sociedad se requiere un estudio de pre factibilidad, con esa visión este presente trabajo tiene por finalidad servir como herramienta básica de guía y consulta sobre los aspectos que deben considerarse para evaluar la factibilidad financiera y económica de proyectos cuya finalidad sea instaurar una manufactura de tipo PYMES y que sirva de punto de para evaluar los objetivos...

  14. Reconstrucción estructuralista de la Teoría del envejecimiento por radicales libres

    OpenAIRE

    O'Lery, María de las Mercedes

    2013-01-01

    O'Lery, M. de las M. (2013). Reconstrucción estructuralista de la Teoría del envejecimiento por radicales libres (Tesis de Doctorado). Universidad Nacional de Quilmes, Bernal, Argentina. Este trabajo pretende, principalmente, ofrecer una reconstrucción de la teoría del envejecimiento por radicales libres, a partir de un enfoque estructuralista y en lo que respecta a sus aspectos sincrónicos. Dicha tarea, exigirá el análisis y la reconstrucción previa de un modelo de reacciones de óxido-red...

  15. Os filhos de desaparecidos políticos da ditadura civil-militar da Argentina e sua produção cinematográfica : um olhar geracional

    OpenAIRE

    Bruna Borges da Silva

    2016-01-01

    Resumo: A pesquisa tem como proposta central abordar e analisar a cinematografia produzida e idealizada por filhos de desaparecidos políticos da última ditadura civil-militar da Argentina (1976-1983). Foram selecionados dois filmes (Los Rubios, 2003 e Infancia Clandestina ¿ 2012) que abordam a temática ditatorial, a partir das memórias de seus diretores, ambos são considerados marcos culturais e políticos no país, pois surgem como rupturas dos discursos memorialístico e cinematográfico previa...

  16. Oclusión temporal de arterias ilíacas internas en cesárea-histerectomía por placenta acreta: enfoque multidisciplinario

    OpenAIRE

    Hasbun H, Jorge; Palaviccini R, Jaime; Osorio P, Raúl; Cerda SM, Sergio; Castro L, Magdalena; Carreño T, Laura; Valdevenito S, Raúl

    2012-01-01

    Objetivo: Evaluar la eficacia y resultados del tratamiento de la placenta acreta previa central en un caso clínico. Durante el embarazo los métodos diagnósticos por imágenes (ultrasonido y resonancia nuclear magnética) precisaron la localización y penetración de la placenta en la pared uterina. En el período inmediato antes del parto, para disminuir la hemorragia, evitar la hipotensión materna y facilitar el procedimiento quirúrgico, se colocaron balones intraarteriales en ambas ilíacas inter...

  17. El camino del ‘desarrollo armonioso’ de China

    OpenAIRE

    Zhou, Hang

    2013-01-01

    Las dos cuestiones esenciales que se plantean en este programa, tanto el crecimiento de la economía como la armonía interna en la sociedad necesaria para conseguirlo, se han convertido en el foco del futuro desarrollo social chino. La aparición de la ‘armonía’ como condición previa por primera vez en el diseño de camino de este país socialista atraído la atención de los estudiosos.

  18. La motivación del aprendizaje en la universidad : Una mirada a las prácticas de los docentes para activar el interés de los estudiantes en disciplinas básico- aplicadas y aplicadas

    OpenAIRE

    Lampugnani, Gladys Adelma; Paso, Mónica

    2012-01-01

    Esta ponencia socializa los resultados de un relevamiento de opinión a docentes del ciclo terminal de la carrera de ingeniería agronómica realizado con el fin de comprender aspectos relativos a la motivación por aprender materias de aplicación. Tal acción fue impulsada por la recurrencia observada en la falta de lectura previa y la pasividad de los estudiantes frente a la propuesta didáctica de un curso particular, el de Terapéutica Vegetal, aunque luego los interrogantes vinculados con el pr...

  19. Antecedentes de la autoeficacia en profesores y estudiantes universitarios: un modelo causal

    OpenAIRE

    MARISA SALANOVA; EVA CIFRE; ROSA M.ª GRAU; SUSANA LLORENS; ISABEL M. MARTÍNEZ

    2005-01-01

    La investigación previa sobre autoeficacia se ha centrado fundamentalmente en sus consecuencias (ej. estrés y desempeño), existiendo pocos estudios empíricos sobre sus antecedentes, por ejemplo los obstáculos y facilitadores situaciones que influyen en las creencias de eficacia. En el presente estudio se pone a prueba un modelo teórico en el que los principales obstáculos y facilitadores en el ámbito de la educación influyen en la autoeficacia vía bienestar psicológico (burnout y engagement) ...

  20. Auto–eficacia docente, motivación del profesor y estrategias de enseñanza

    OpenAIRE

    Rodríguez, Susana; Núñez Perez, José Carlos; Valle, Antonio; Blas, Rebeca; Rosário, Pedro

    2009-01-01

    Según los resultados de la investigación previa, los logros de los profesores en relación con sus actividades docentes van a depender, en buena medida, de la confianza que tengan en sí mismos para abordar todos estos cambios que conlleva su nuevo rol. En el presente estudio se han pretendido dos objetivos: a) aportar información sobre cómo los profesores coordinan diferentes ámbitos de autoeficacia (para optimizar el proceso instruccional, para gestionar el aula y para implicar al estudiante ...

  1. New sample treatment strategies for the determination of organic contaminants in environmental matrices.

    OpenAIRE

    Casas Ferreira, Ana María

    2011-01-01

    [ES] El objeto general de esta memoria consiste en proponer y desarrollar nuevas estrategias de tratamiento de muestra para la determinación de contaminantes orgánicos en matrices medioambientales. En muchos casos, cuando se trabaja con diferentes matrices, tales como aguas o suelos, es necesaria la utilización de técnicas de pretratamiento de muestra previas al análisis instrumental, cuyo objetivo principal es aislar los analitos de interés del resto de componentes presentes en la matriz...

  2. Mujer en la publicidad televisiva franquista de los años 60: caso Soberano

    Directory of Open Access Journals (Sweden)

    Patricia Pujante Crespo

    2015-07-01

    Full Text Available El presente artículo da cuenta de una investigación previa que analiza el papel atribuido a la mujer española en la década de 1960 en la publicidad televisiva. Lo que se pretende es demostrar la influencia de la dictadura franquista en los medios de comunicación y en la publicidad, utilizándolos como estrategia propagandística del régimen y convirtiéndolos en un reflejo de la sociedad.

  3. Imagenoligía para el siglo XXI resonancia magnetica

    OpenAIRE

    Mejía González, Mauricio; Fundación Valle de Lili

    1998-01-01

    ¿Qué es la resonancia magnetica?/¿Cómo funciona la resonancia magnética?/¿Para que se utiliza la resonancia magnética?/¿En que casos no se debe hacer resonancia magnética?/¿Se puede hacer resonancia a niños o mujeres embarazadas?/¿Qué se siente durante el examen?/¿Se requiere de medio de contraste?/¿Qué preparación previa se debe tener?/¿Que ventajas tiene la resonancia sobre otros métodos para imágenes diagnósticas?

  4. La estructura de la unidad de Malpica-Tui ( Cordillera Varisca en Iberia)

    OpenAIRE

    Llana Fúnez, Sergio

    2000-01-01

    La Unidad de Malpica-Tui(UMT) está constituída por una secuencia metasedimentaria que incluye diversos cuerpos estratiformes de rocas ortoderivadas ácidas y básicas. Todo el conjunto de rocas muestra una fábrica tectónica muy penetrativa. El carácter heterogéneo de la deformación durante el desarrollo de la fábrica ha permitido la preservación parcial de la historia previa de las rocas, como: estructuras sedimentarias, texturas ígneas y asociaciones minerales de AP-BIT. E...

  5. Osteonecrosis de los maxilares y bifosfonatos : revisión

    OpenAIRE

    Bongiovanni, Isabel

    2012-01-01

    La osteonecrosis de los maxilares es la necrosis y exposición del hueso de la mandíbula y el maxilar, asociada al consumo de bifosfonatos. Estos son una familia de drogas que se utiliza en el tratamiento de alteraciones óseas causadas principalmente por tumores malignos (mama y próstata) y osteoporosis. No existe irradiación previa. El hueso macroscópicamente se ve sucio avascular. El objetivo de este artículo es profundizar el conoc...

  6. Osteonecrosis of the jaw associated to bisphosphonates treatment in osteoporosis patients: a review

    OpenAIRE

    Gutiérrez Restrepo, Johnayro

    2013-01-01

    La osteonecrosis de mandíbula es una entidad que se viene describiendo desde 2003 y se define como la presencia de un defecto en la mucosa oral que lleva a exposición del hueso de la mandíbula y del maxilar que falla en cicatrizar en un periodo de ocho semanas, en un paciente en tratamiento con bifosfonatos y sin exposición previa a radioterapia en cuello o en la cabeza. En este artículo se hace una revisión de la literatura respecto a la epidemiología, la fisiopatología, los estudios diagnós...

  7. Estructura y legitimación del delito de colusión e impunidad en el distrito judicial de Huánuco

    OpenAIRE

    Vásquez Solís, Leoncio

    2015-01-01

    El delito de colusión es un tipo penal especial, que exige para la determinación correcta de imputación el conocimiento de normas extrapenales para configurar el ilícito, sin embargo, debido a la complejidad de las normas previas a la tipificación del delito de colusión, y la necesidad de punibilidad este tipo de delitos que afecta gravemente el normal desarrollo del sistema financiero público del Estado, el legislador ha tenido de recurrir a un conjunto de modificatorias...

  8. Nuevas evidencias geofísicas de la existencia de una caldera cubierta en laguna Pozuelos: Puna norte

    OpenAIRE

    Claudia B Prezzi; Federico Lince Klinger

    2010-01-01

    En el extremo sur de la cuenca de laguna de Pozuelos aflora el complejo volcánico Pan de Azúcar. El mismo está integrado por varios centros eruptivos de composición dacítica y morfología dómica que poseen una edad de ~12 Ma. Interpretaciones previas de líneas sísmicas y un relevamiento magnetométrico detallado indicaron la presencia de cuerpos intrusivos no aflorantes. La determinación de la existencia de nuevos cuerpos intrusivos no aflorantes en la zona resulta de interés debido a que: 1) e...

  9. Motivaciones de los jóvenes uninorteños para participar en elecciones locales y regionales en 2011

    OpenAIRE

    Diana Rico Revelo

    2013-01-01

    Este estudio describe algunas motivaciones vinculadas a la intención de voto de 262 estudiantes de la Universidad del Norte (Barranquilla, Colombia) en las elecciones para la Alcaldía de Barranquilla y la Gobernación del Atlántico en 2011. Se utilizó una metodología descriptiva con un instrumento mixto aplicado una semana previa a las elecciones. Las dimensiones analizadas fueron: interés en la política, socialización política primaria, confianza en el partido y en el candidato, ideología y b...

  10. Determinación de metabolitos secundarios en Physalis angulata (L) 1758 "mullaca" y su importancia en el efecto hipoglucemiante en Rattus norvegicus "rata albina", Iquitos - Perú;

    OpenAIRE

    Donayre Ramirez, Marjorie Raquel; Carrasco Montañez, Daniel Diomedes

    2013-01-01

    El presente trabajo se desarrolló en el laboratorio de Química Analítica de la Universidad Nacional de la Amazonía Peruana (UNAP) y en el Instituto de Medicina Tradicional (IMET) de la Ciudad de !quitos - Perú. Se evaluó la actividad hipoglucemiante de los extractos, etanólico y metanólico de raíz, tallo y hoja de Physalis angulata (Linneo) "mullaca", en ratas albinas machos Rattus norvegicus cepa Holtzman, previa inducción de un estado de hiperglicemia con alloxano al 5% (125mg/kg de masa co...

  11. Dibujo arquitectónico : La representación analítico-descriptiva de un tema vivido o documentado por los alumnos: mosaico

    OpenAIRE

    Carbonari, Fabiana Andrea

    1999-01-01

    El espacio arquitectónico tiene una morfología definida, de la misma manera que los elementos, fijos o móviles, que forman parte de él. El mosaico es un ornamento de ese hecho arquitectónico que se manifiesta y organiza bidimensionalmente integrándose al soporte brindado por la arquitectura. La existencia, tanto del espacio arquitectónico como del mosaico, puede ser real o imaginaria. Estas dos posibilidades dependen deque la obra haya sido o no ejecutada en forma previa a su dibujo. Será rea...

  12. Dificultades en la investigación preparatoria en delitos de trata de personas por explotación sexual de menores en la ciudad de Iquitos durante los años 2013 y 2014.

    OpenAIRE

    Vegas Pérez, María Luisa

    2016-01-01

    Problema: ¿Cuáles son las dificultades en la Investigación Preparatoria en Delitos de Trata de Personas por Explotación Sexual de menores en la ciudad de Iquitos durante los años 2013 y 2014? Objetivo: Identificar las dificultades en la investigación preparatoria en Delitos de Trata de Personas por Explotación Sexual de menores en la ciudad de Iquitos durante los años 2013 y 2014. Material y método: Se aplicó un cuestionario estructurado a una muestra de 500 sujetos, previa ...

  13. Cerclaje pericostal en el tórax batiente con construcción de costillas externas artificiales

    OpenAIRE

    Bruk Bekele Jembere; Orestes N Mederos Curbelo; Jesús Valdés Jiménez; Juan Carlos Barreras Ortega; Carlos Alberto Romero Díaz; Alexis Cantero Ronquillo

    2002-01-01

    Se presenta un prototipo de fijador costal externo construido con duroaluminio maleable mediante la utilización del sistema de cerclaje AO, basado en una experiencia previa con un tórax inestable, en la cual se utilizó el sistema AO con costillas externas fabricadas de yeso y láminas de acero. La evolución de la enferma fue excelente lo que motivó a confeccionar el fijador costal reutilizable, el cual se usó después en otros 2 pacientes con resultados similares, uno de ellos con un tórax bati...

  14. On the notion of fuzzy adjunctions between fuzzy orders

    OpenAIRE

    Cabrera, Inma P.; Cordero-Ortega, Pablo; García-Pardo, Francisca; Ojeda-Aciego, Manuel

    2015-01-01

    Las adjunciones (también denominadas conexiones de Galois isótonas) entre dos estructuras matemáticas proporcionan una manera de conectar ambas teorías que permite compartir las ventajas de ambas. Hay varios resultados en la literatura previa acerca de las condiciones necesarias y suficientes para la existencia de conexiones de Galois entre dos conjuntos parcialmente ordenados. En otros trabajos anteriores, los autores han estudiado la existencia y construcción del adjunto por la derecha de u...

  15. Diagnostic accuracy of the ultrasonography in complicated pregnancy

    International Nuclear Information System (INIS)

    Cha, Kyung Soo; Kim, Kun Sang; Park, Soo Soung

    1983-01-01

    Ultrasonography is an invaluable diagnostic method in Obstetrics. It provides safe, speedy and repeatable way to obtain image of normal and abnormal pregnancy. The ultrasonograms of 167 patients with suspicion of complicated pregnancy were analyzed. The results were as follows. 1. 86 patients showed normal ultrasonogram(50.9%). 100% in intrauterine fetal death and gross fetal anomaly, 100% in abnormal fetal position and number, 95% in pregnancy with pelvic mass, 83% in ectopic pregnancy, 81% in abortion, 78% in molar pregnancy, 74% in plancenta previa. 3. Ultrasonic diagnosis of abrupto placenta was difficult. 4. Diagnostic accuracy was 80% in bicornuate uterus and double vagina

  16. Cuerpos singulares: Una lectura desde el pensamiento de Judith Butler

    OpenAIRE

    Galé Moyano, María José; Burgos Díaz, Elvira

    2013-01-01

    La aproximación que constituye este trabajo se inicia en la vacilación al respecto de la inserción del propio cuerpo, mi cuerpo, en distintos contextos vitales, de un cuestionamiento de la identidad a lo largo de la vida. Ello supondría un alejamiento de la pretendida objetividad en función de la cual el cuerpo vivo que investiga se comprende como algo ajeno a lo estudiado, una abstracción capaz de aproximarse sin una biografía previa, sin una configuración corporal concreta, a aquello que co...

  17. Lo que el ojo no ve: la burbuja de las "TIC" conquista la Educación

    OpenAIRE

    Garnica Hoz, José Luis

    2012-01-01

    RESUMEN: Durante mi experiencia como alumno de la Universidad de Cantabria he vivenciado una modernización de los recursos tecnológicos usados por el docente. Para muchos, esto ha supuesto un cambio de paradigma en la educación. Para otros, una simple transposición de medios adaptados a las prácticas preexistentes. Este TFG analizará cómo el boom revolucionario de las TIC se ha instalado en la Educación, sin previa preparación y justificación de por qué estos nuevos medios pueden facilitar la...

  18. Factores clínicos asociados a multirresistencia bacteriana en un hospital de cuarto nivel

    Directory of Open Access Journals (Sweden)

    Eliana Saldarriaga Quintero

    Full Text Available Introducción: Las infecciones causadas por bacterias multirresistentes aumentan la morbilidad, la mortalidad, los costos de la atención y ocasionan dificultades para el tratamiento. Conocer los factores asociados a la infección por bacterias multirresistentes es clave para una adecuada vigilancia y control que permita mejorar la atención de los pacientes en los hospitales. Objetivo: Determinar factores clínicos asociados a infección por bacterias multirresistentes en un hospital de alta complejidad. Materiales y métodos: Se realizó un estudio de casos y controles utilizando las historias clínicas de pacientes hospitalizados. La selección de los controles se hizo por muestreo aleatorizado simple. Los análisis de los datos se realizaron en el software SPSS 21.0, se calcularon medidas descriptivas y de asociación (U de Mann-Whitney, chi-cuadrado y OR, y se realizó un modelo multivariado mediante regresión logística para el cálculo del OR ajustado. Resultados: Se encontraron asociaciones significativas con inmunosupresión por medicamentos (OR = 2,58, trasplante (OR = 2,88, hospitalización (OR = 1,73 o cirugía (OR = 1,78 en los 3 meses previos a la infección, diálisis (OR = 3,53, catéter venoso central (OR = 2,16, nutrición parenteral (OR = 2,06 y terapia antibiótica en las 48 h previas a la infección (OR = 1,86. En el modelo multivariado fueron importantes la hospitalización previa (OR = 1,83 y tener EPOC (OR = 3,07. Conclusiones: La hospitalización previa y la EPOC son factores de riesgo independientes para adquirir infección por bacterias multirresistentes. Además, aunque no fue posible estimar el riesgo debido a que no se encontraron controles expuestos, la nutrición parenteral y el uso de quinolonas en las 48 h previas a la infección fueron importantes en la ocurrencia del evento.

  19. Assessing the links among adolescent and youth offending, antisocial behaviour, victimization, drug use, and gender

    OpenAIRE

    Estefanía Estévez; Nicholas P. Emler

    2011-01-01

    Este estudio ex post facto se centra en el análisis de tres factores de riesgo relacionados con la delincuencia juvenil: la implicación en comportamientos antisociales,el hecho de haber sido víctima de algún acto delictivo, y el consumo de drogas. La investigación previa sobre estos factores de riesgo sigue presentando cuestiones no resueltas sobre las direcciones de influencia. Además, los estudios con población femenina son mucho más escasos que aquellos desarrollados con población masculin...

  20. La representación de la violencia en los tráileres de las películas de Walt Disney Pictures

    OpenAIRE

    Garrido Lora, Manuel

    2010-01-01

    Esta investigación analiza la representación de la violencia en los tráileres de 23 películas de animación producidas por Walt Disney Pictures. Mediante la metodología del análisis de contenido y las utilidades propias de la morfología y analítica narrativas, el investigador, con la experiencia previa del análisis de la violencia en los spots publicitarios, expone en este trabajo las cualidades de las acciones violentas presentes en dichos tráileres, y concluye que, atendiendo a investigacion...